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Sample records for early loaded implants

  1. Numerical assessment of bone remodeling around conventionally and early loaded titanium and titanium-zirconium alloy dental implants.

    PubMed

    Akça, Kıvanç; Eser, Atılım; Çavuşoğlu, Yeliz; Sağırkaya, Elçin; Çehreli, Murat Cavit

    2015-05-01

    The aim of this study was to investigate conventionally and early loaded titanium and titanium-zirconium alloy implants by three-dimensional finite element stress analysis. Three-dimensional model of a dental implant was created and a thread area was established as a region of interest in trabecular bone to study a localized part of the global model with a refined mesh. The peri-implant tissues around conventionally loaded (model 1) and early loaded (model 2) implants were implemented and were used to explore principal stresses, displacement values, and equivalent strains in the peri-implant region of titanium and titanium-zirconium implants under static load of 300 N with or without 30° inclination applied on top of the abutment surface. Under axial loading, principal stresses in both models were comparable for both implants and models. Under oblique loading, principal stresses around titanium-zirconium implants were slightly higher in both models. Comparable stress magnitudes were observed in both models. The displacement values and equivalent strain amplitudes around both implants and models were similar. Peri-implant bone around titanium and titanium-zirconium implants experiences similar stress magnitudes coupled with intraosseous implant displacement values under conventional loading and early loading simulations. Titanium-zirconium implants have biomechanical outcome comparable to conventional titanium implants under conventional loading and early loading.

  2. Early versus delayed loading of mandibular implant-supported overdentures: 5-year results.

    PubMed

    Turkyilmaz, Ilser; Tözüm, Tolga F; Tumer, Celal

    2010-05-01

    Because of poor retention of complete removable dentures for edentulous patients, implant-supported mandibular overdentures have lately become a popular alternative for them. The aims of this prospective study were to evaluate treatment outcomes of mandibular overdentures supported by two unsplinted early-loaded implants and compare these results with those for delayed-loaded implants. A total of 26 edentulous patients were treated with two unsplinted implants supporting a mandibular overdenture. All implants were placed in the canine regions of each mandible according to the one-stage surgical protocol. There were two groups: test group, in which the overdenture was connected 1 week after surgery, and control group, in which the overdenture was connected 3 months after surgery. Standardized clinical and radiographic parameters were recorded at surgery, and after 3, 6, 12, and 18 months, and 2, 3, 4, and 5 years. No implants were lost, and 0.93 +/- 0.3 mm marginal bone resorption was noted for all implants after 5 years. Clinical implant stability measurements, clinical peri-implant parameters, and marginal bone resorptions showed no statistically significant differences between the two groups over 5 years. The results of this prospective clinical study suggest that there is no significant difference in the clinical and radiographic state of patients treated with implant supported mandibular overdentures loaded either 1 week or 3 months after surgery.

  3. Clinical outcomes of immediate/early loading of dental implants. A literature review of recent controlled prospective clinical studies.

    PubMed

    Sennerby, L; Gottlow, J

    2008-06-01

    Two previous reviews have evaluated the clinical outcomes of immediate/early loading of dental implants based on studies published until 2005.(1,2) The aim of the present paper was to review controlled clinical studies on the subject published since 2005 including at least 10 patients in each group followed for at least one year in function. Six comparative studies were found and none of these showed any differences in survival rates or marginal bone loss after one to five years. Most authors used specified inclusion criteria to avoid known risk factors such as soft bone, short implants and bruxism. Data from one randomized study in the edentulous maxilla showed no differences between early and delayed loading in consecutive clinical routine cases including short implants and soft bone. Three additional studies comparing different surfaces or implant designs under immediate loading were reviewed. No differences between implants with a moderately rough or smooth surface topography were observed. The data add to the previous bulk of evidence that various designs of implants can be loaded shortly after their placement in both the mandible and the maxilla. However, one study reported on marginal bone loss around a novel one-piece implant design leading to implant failure which was not seen for control two-piece implants.(3).

  4. Mandibular single-implant overdentures: preliminary results of a randomised-control trial on early loading with different implant diameters and attachment systems.

    PubMed

    Alsabeeha, Nabeel H M; Payne, Alan G T; De Silva, Rohana K; Thomson, W Murray

    2011-03-01

    To determine surgical and prosthodontic outcomes of mandibular single-implant overdentures, opposing complete maxillary dentures, using a wide diameter implant and large ball attachment system compared with different regular diameter implants with standard attachment systems. Thirty-six edentulous participants (mean age 68 years, SD 9.2) were randomly assigned into three treatment groups (n=12). A single implant was placed in the mandibular midline of participants to support an overdenture using a 6-week loading protocol. The control group received Southern regular implants and standard ball attachments. One group received Southern 8-mm-wide implants and large ball attachments. Another group received Neoss regular implants and Locator attachments. Parametric and non-parametric tests of a statistical software package (SPSS) were used to determine between groups differences in marginal bone loss, implant stability, implant, and prosthodontic success (P<0.05). Implant success after 1 year was 75% for Southern regular implant (control) group; and 100% for the Southern wide and Neoss regular implant groups (P=0.038). Mean marginal bone loss at 1 year was 0.19 mm (SD 0.39) without significant differences observed. Implant stability quotient (ISQ) at baseline was significantly lower for the Southern regular (control) group than the other two groups (P=0.001; P=0.009). At 1 year, no significant difference in implant stability was observed (mean ISQ 74.6, SD 6.1). The change in implant stability from baseline to 1 year was significant for the control group (P=0.025). Prosthodontic success was comparable between the groups but the maintenance (41 events overall, mean 1.2) was greater for the Locator and the standard ball attachments. Mandibular single-implant overdentures are a successful treatment option for older edentulous adults with early loading protocol using implants of different diameters and with different attachment systems. © 2010 John Wiley & Sons A/S.

  5. Effects of Early Moderate Loading on Implant Stability: A Retrospective Investigation of 634 Implants with Platform Switching and Morse-Tapered Connections.

    PubMed

    Romanos, Georgios; Grizas, Eleftherios; Laukart, Elena; Nentwig, Georg-Hubertus

    2016-04-01

    This retrospective investigation aimed to evaluate the effect of early moderate loading (EML) on implant stability. Following 6 weeks of conventional healing, 634 dental implants (Ankylos®, Dentsply Implants, Mannheim, Germany) inserted in 247 patients were uncovered. Provisional restorations were placed in infra-occlusion in partially edentulous patients and in full occlusion in edentulous patients. Patients were instructed to consume a soft/liquid diet until final restorations were delivered after approximately 6 weeks. Periotest values (PTVs) at the time of uncovering and after EML were assessed in order to calculate the change in PTV (ΔPTV). Improvement of the PTV was analyzed to account for dependencies between measurements on multiple implants of a single patient, along with other factors. No implant was lost during the EML. After a mean loading time of 3 years (± 1.7 years), the implant survival rate was 98.74%. The PTV of 556 implants decreased (improved) over the course of the study. The ΔPTV was statistically significant (p = .0001), and none of the factors analyzed appeared to influence it. The EML of implants does not impair the implants' stability, as determined by Periotest. On the contrary, early moderate loading seems to be beneficial at compromised bone qualities. © 2015 Wiley Periodicals, Inc.

  6. Immediate versus early loading of two implants placed with a flapless technique supporting mandibular bar-retained overdentures: a single-blinded, randomised controlled clinical trial.

    PubMed

    Cannizzaro, Gioacchino; Leone, Michele; Esposito, Marco

    2008-01-01

    To evaluate the efficacy of immediate loading versus early loading at 6 weeks of bar-retained mandibular overdentures supported by two implants placed with a flapless technique. Sixty patients were randomised: 30 to the immediately loaded group and 30 to the early loaded group. To be immediately loaded, implants had to be inserted with a minimum torque > 48 Ncm. Outcome measures were prosthesis and implant failures, biological and biomechanical complications, patient satisfaction, and Implant Stability Quotient (ISQ) assessed with a resonance frequency analysis instrument. Sixty implants were placed in each group. Flaps had to be raised in nine patients to check drill direction or to better visualise the area after multiple teeth extraction. Two implants in two patients did not reach the planned insertion torque and were immediately replaced by larger diameters ones. After 1 year no drop out occurred and two early loaded implants failed in two patients. There were no statistically significant differences between groups for prosthesis failures, implant losses, complications, and mean ISQ values; however, patients in the immediately loaded group were significantly more satisfied than those loaded early. When comparing mean ISQ values taken 6 weeks after placement with 1-year data within each group, values decreased significantly. Mandibular overdentures can be successfully loaded the same day of implant placement with a minimally invasive surgery, increasing patient satisfaction while decreasing treatment time and patient discomfort. No apparent advantages were seen when loading the overdentures at 6 weeks.

  7. Immediate versus early non-occlusal loading of dental implants placed flapless in partially edentulous patients: a 3-year randomized clinical trial.

    PubMed

    Merli, Mauro; Moscatelli, Marco; Mariotti, Giorgia; Piemontese, Matteo; Nieri, Michele

    2012-02-01

    To compare immediate versus early non-occlusal loading of dental implants placed flapless in a 3-year, parallel group, randomized clinical trial. The study was conducted in a private dental clinic between July 2005 and July 2010. Patients 18 years or older were randomized to receive implants for fixed partial dentures in cases of partial edentulism. The test group was represented by immediate non-occlusal implant loading, whereas the control group was represented by early non-occlusal implant loading. The outcome variables were implant failure, complications and radiographic bone level at implant sites 3 years after loading, measured from the implant-abutment junction to the most coronal point of bone-to-implant contact. Randomization was computer-generated with allocation concealment by opaque sequentially numbered sealed envelopes, and the measurer was blinded to group assignment. Sixty patients were randomized: 30 to the immediately loaded group and 30 to the early loaded group. Four patients dropped out; however, the data of all patients were included in the analysis. No implant failure occurred. Two complications occurred in the control group and one in the test group. The mean bone level at 3 years was 1.91 mm for test group and 1.59 mm for control group. The adjusted difference in bone level was 0.26 mm (CI 95% -0.08 to 0.59, p = 0.1232). The null hypothesis of no difference in failure rates, complications and bone level between implants that were loaded immediately or early at 3 years cannot be rejected in this randomized clinical trial. © 2011 John Wiley & Sons A/S.

  8. Marginal Bone Loss Around Early-Loaded SLA and SLActive Implants: Radiological Follow-Up Evaluation Up to 6.5 Years.

    PubMed

    Şener-Yamaner, Işil Damla; Yamaner, Gökhan; Sertgöz, Atilla; Çanakçi, Cenk Fatih; Özcan, Mutlu

    2017-08-01

    The aim of this study was to compare marginal bone loss around early-loaded SLA and SLActive tissue-level implants (Straumann Dental Implants; Institut Straumann AG, Basel, Switzerland) after a mean of 81-month follow-up period. One hundred seven SLA and 68 SLActive implants were placed in 55 patients and loaded with final restoration after 8 and 3 weeks of healing time, respectively. Marginal bone loss around implants was determined radiographically at initial and after a mean observation time ranging between 20 and 81 months. The effect of location (mandible vs maxilla), smoking habit, sex, implant length and diameter, and the type of prosthesis on the marginal bone loss was evaluated. The overall cumulative survival rate was 98.2% being 99% for SLA implants and 97% for SLActive implants. After 20-month follow-up period, mean marginal bone loss values for the SLA and SLActive implants were 0.24 and 0.17 mm, respectively. After 81 months, mean marginal bone loss for the SLA and SLActive implants reached 0.71 and 0.53 mm, respectively. Marginal bone loss was affected by the length and type of implant and patients' smoking habit after a mean observation time of 20 months. However, none of the parameters had any significant effect on the marginal bone loss after a follow-up period of 81 months. With both SLA and SLActive implants, successful clinical results could be achieved up to 6.5 years of follow-up period.

  9. Positive effects of cell-free porous PLGA implants and early loading exercise on hyaline cartilage regeneration in rabbits.

    PubMed

    Chang, Nai-Jen; Lin, Chih-Chan; Shie, Ming-You; Yeh, Ming-Long; Li, Chien-Feng; Liang, Peir-In; Lee, Kuan-Wei; Shen, Pei-Hsun; Chu, Chih-Jou

    2015-12-01

    The regeneration of hyaline cartilage remains clinically challenging. Here, we evaluated the therapeutic effects of using cell-free porous poly(lactic-co-glycolic acid) (PLGA) graft implants (PGIs) along with early loading exercise to repair a full-thickness osteochondral defect. Rabbits were randomly allocated to a treadmill exercise (TRE) group or a sedentary (SED) group and were prepared as either a PGI model or an empty defect (ED) model. TRE was performed as a short-term loading exercise; SED was physical inactivity in a free cage. The knees were evaluated at 6 and 12 weeks after surgery. At the end of testing, none of the knees developed synovitis, formed osteophytes, or became infected. Macroscopically, the PGI-TRE group regenerated a smooth articular surface, with transparent new hyaline-like tissue soundly integrated with the neighboring cartilage, but the other groups remained distinct at the margins with fibrous or opaque tissues. In a micro-CT analysis, the synthesized bone volume/tissue volume (BV/TV) was significantly higher in the PGI-TRE group, which also had integrating architecture in the regeneration site. The thickness of the trabecular (subchondral) bone was improved in all groups from 6 to 12 weeks. Histologically, remarkable differences in the cartilage regeneration were visible. At week 6, compared with SED groups, the TRE groups manifested modest inflammatory cells with pro-inflammatory cytokines (i.e., TNF-α and IL-6), improved collagen alignment and higher glycosaminoglycan (GAG) content, particularly in the PGI-TRE group. At week 12, the PGI-TRE group had the best regeneration outcomes, showing the formation of hyaline-like cartilage, the development of columnar rounded chondrocytes that expressed enriched levels of collagen type II and GAG, and functionalized trabecular bone with osteocytes. In summary, the combination of implanting cell-free PLGA and performing an early loading exercise can significantly promote the full

  10. Early Loading of Fluoridated Implants Placed in Fresh Extraction Sockets and Healed Bone: A 3- to 5-Year Clinical and Radiographic Follow-Up Study of 39 Consecutive Patients.

    PubMed

    Oxby, Gert; Oxby, Fredrik; Oxby, Johan; Saltvik, Tomas; Nilsson, Peter

    2015-10-01

    Immediate placement of implants in extraction sockets for early loading is an attractive treatment modality due to reduced treatment time. However, the outcome of fluoridated implants in this situation with regard to bone levels and health of soft tissues is not well documented. To evaluate the outcome of early loading of OsseoSpeed(™) dental implants placed into fresh extraction sockets and healed bone in consecutive patients treated in a private clinic. A total of 182 OsseoSpeed(™) implants (Astra Tech Implant System, DENTSPLY Implants, Mölndal, Sweden), 72 in immediate extraction sockets and 110 in healed sites, were placed in 39 consecutive patients. The implants were loaded with permanent restorations within 60 days (average 31 days). Clinical and radiographic follow-up examinations were performed annually for at least 3 years (mean 55 months). An aesthetic index was used to evaluate the soft tissues adjacent to the prosthetic restorations. No implant was lost during the observation period, giving a survival rate of 100%. Bone level changes during the observation period were minimal, with a mean marginal bone loss of 0.3 ± 0.9 mm around the delayed implants and a mean marginal bone gain of 0.3 ± 1.4 mm around the immediate implants (p = .0036). The frequency distribution of bone level revealed that 85% of implants placed in fresh extraction sockets and 84% of implants in healed bone did not show any loss of bone level during follow-up (p = NS). Soft tissue complications were observed at two immediate implant sites in one patient. The remaining 180 implants received the highest aesthetic score. Moreover, no signs of peri-implant purulent infection or aggressive bone loss were found during the follow-up period. Early loading of fluoridated implants with permanent constructions appears to be a viable therapy for implants placed immediately in extraction sites and in healed bone. © 2014 Wiley Periodicals, Inc.

  11. Development of implant loading device for animal study about various loading protocol: a pilot study

    PubMed Central

    Yoon, Joon-Ho; Park, Young-Bum; Cho, Yuna; Kim, Chang-Sung; Choi, Seong-Ho; Moon, Hong-Seok; Lee, Keun-Woo

    2012-01-01

    PURPOSE The aims of this pilot study were to introduce implant loading devices designed for animal study and to evaluate the validity of the load transmission ability of the loading devices. MATERIALS AND METHODS Implant loading devices were specially designed and fabricated with two implant abutments and cast metal bars, and orthodontic expansion screw. In six Beagles, all premolars were extracted and two implants were placed in each side of the mandibles. The loading device was inserted two weeks after the implant placement. According to the loading protocol, the load was applied to the implants with different time and method,simulating early, progressive, and delayed loading. The implants were clinically evaluated and the loading devices were removed and replaced to the master cast, followed by stress-strain analysis. Descriptive statistics of remained strain (µε) was evaluated after repeating three cycles of the loading device activation. Statistic analysis was performed using nonparametric, independent t-test with 5% significance level and Friedman's test was also used for verification. RESULTS The loading devices were in good action. However, four implants in three Beagles showed loss of osseointegration. In stress-strain analysis, loading devices showed similar amount of increase in the remained strain after applying 1-unit load for three times. CONCLUSION Specialized design of the implant loading device was introduced. The loading device applied similar amount of loads near the implant after each 1-unit loading. However, the direction of the loads was not parallel to the long axis of the implants as predicted before the study. PMID:23236575

  12. Efficacy of standard (SLA) and modified sandblasted and acid-etched (SLActive) dental implants in promoting immediate and/or early occlusal loading protocols: a systematic review of prospective studies.

    PubMed

    Chambrone, Leandro; Shibli, Jamil Awad; Mercúrio, Carlos Eduardo; Cardoso, Bruna; Preshaw, Philip M

    2015-04-01

    To assess the survival percentage, clinical and radiographic outcomes of sandblasted and acid-etched (SLA) dental implants and its modified surface (SLActive) in protocols involving immediate and early occlusal loading. MEDLINE, EMBASE and the Cochrane Oral Health Group's Trials Register CENTRAL were searched in duplicate up to, and including, June 2013 to include randomised controlled trials (RCTs) and prospective observational studies of at least 6-month duration published in all languages. Studies limited to patients treated with SLA and/or SLActive implants involving a treatment protocol describing immediate and early loading of these implants were eligible for inclusion. Data on clinical and/or radiographic outcomes following implant placement were considered for inclusion. Of the 447 potentially eligible publications identified by the search strategy, seven RCTs comprising a total of 853 implants (8% titanium plasma-sprayed, 41.5% SLA and 50.5% SLActive) and 12 prospective observational studies including 1394 SLA and 145 SLActive implants were included in this review. According to the Cochrane Collaboration's tool for assessing risk of bias, one of the studies was considered to be at a low risk of bias, whereas the remaining studies were considered to be at an unclear risk. Regarding the observational studies, all of them presented a medium methodological quality based on the Modified Newcastle-Ottawa scale. There were no significant differences reported in the studies in relation to implant loss or clinical parameters between the immediate/early loading and delayed loading protocols. Overall, 95% of SLA and 97% of SLActive implants still survive at the end of follow-up. Despite of the positive findings achieved by the included studies, few RCTs were available for analysis for SLActive implants. Study heterogeneity, scarcity of data and the lack of pooled estimates represent a limitation between studies' comparisons and should be considered when interpreting

  13. Critical review of immediate implant loading.

    PubMed

    Gapski, Ricardo; Wang, Hom-Lay; Mascarenhas, Paulo; Lang, Niklaus P

    2003-10-01

    Implant dentistry has become successful with the discovery of the biological properties of titanium. In the original protocol, studies have advocated a 2-stage surgical protocol for load-free and submerged healing to ensure predictable osseointegration. However, the discomfort, inconvenience, and anxiety associated with waiting period remains a challenge to both patients and clinicians. Hence, loading implant right after placement was attempted and has gained popularity among clinicians. Issues/questions related to this approach remain unanswered. Therefore, it is the purpose of this review article to (1). review and analyze critically the current available literature in the field of immediate implant loading and (2). discuss, based on scientific evidence, factors that may influence this treatment modality. Literature published over the past 20 years was selected and reviewed. Findings from these studies were discussed and summarized in the tables. The advantages and disadvantages associated with immediate implant loading were analyzed. Factors that may influence the success of immediate implant loading, including patient selection, type of bone quality, required implant length, micro- and macrostructure of the implant, surgical skill, need for achieving primary stability/control of occlusal force, and prosthesis guidelines, were thoroughly reviewed and discussed. Various studies have demonstrated the feasibility and predictability of this technique. However, most of these articles are based on retrospective data or uncontrolled cases. Randomized, prospective, parallel-armed longitudinal human trials are primarily based on short-term results and long-term follow-ups are still scarce in this field. Nonetheless, from available literature, it may be concluded that anatomic locations, implant designs, and restricted prosthetic guidelines are key to ensure successful outcomes. Future studies, preferably randomized, prospective longitudinal studies, are certainly needed

  14. The dynamic natures of implant loading.

    PubMed

    Wang, Rui-Feng; Kang, Byungsik; Lang, Lisa A; Razzoog, Michael E

    2009-06-01

    A fundamental problem in fully understanding the dynamic nature of implant loading is the confusion that exists regarding the torque load delivered to the implant complex, the initial force transformation/stress/strain developed within the system during the implant complex assembly, and how the clamping forces at the interfaces and the preload stress impact the implant prior to any external loading. The purpose of this study was to create an accurately dimensioned finite element model with spiral threads and threaded bores included in the implant complex, positioned in a bone model, and to determine the magnitude and distribution of the force transformation/stress/strain patterns developed in the modeled implant system and bone and, thus, provide the foundational data for the study of the dynamic loading of dental implants prior to any external loading. An implant (Brånemark Mark III), abutment (CeraOne), abutment screw (Unigrip), and the bone surrounding the implant were modeled using HyperMesh software. The threaded interfaces between screw/implant and implant/bone were designed as a spiral thread helix assigned with specific coefficient of friction values. Assembly simulation using ABAQUS and LS-DYNA was accomplished by applying a 32-Ncm horizontal torque load on the abutment screw (Step 1), then decreasing the torque load to 0 Ncm to simulate the wrench removal (Step 2). The postscript data were collected and reviewed by HyperMesh. A regression analysis was used to depict the relationships between the torque load and the mechanical parameters. During the 32-Ncm tightening sequence, the abutment screw elongated 13.3 mum. The tightening torque generated a 554-N clamping force at the abutment/implant interface and a 522-N preload. The von Mises stress values were 248 MPa in the abutment at the abutment-implant interface, 765 MPa at the top of the screw shaft, 694 MPa at the bottom of the screw shaft, 1365 MPa in the top screw thread, and 21 MPa in the bone at the

  15. Effect of cyclic loading and retightening on reverse torque value in external and internal implants

    PubMed Central

    Cho, Woong-Rae; Huh, Yoon-Hyuk; Park, Chan-Jin

    2015-01-01

    PURPOSE The aim of this study was to evaluate the effect of cyclic loading and screw retightening on reverse torque value (RTV) in external and internal type implants. MATERIALS AND METHODS Cement-retained abutments were connected with 30 Ncm torque to external and internal type implants. Experimental groups were classified according to implant connection type and retightening/loading protocol. In groups with no retightening, RTV was evaluated after cyclic loading for 100,000 cycles. In groups with retightening, RTV was measured after 3, 10, 100 cycles as well as every 20,000 cycles until 100,000 cycles of loading. RESULTS Every group showed decreased RTV after cyclic loading. Before and after cyclic loading, external type implants had significantly higher RTVs than internal type implants. In external type implants, retightening did not affect the decrease in RTV. In contrast, retightening 5 times and retightening after 10 cycles of dynamic loading was effective for maintaining RTV in internal type implants. CONCLUSION Retightening of screws is more effective in internal type implants than external type implants. Retightening of screws is recommended in the early stage of functional loading. PMID:26330975

  16. Effect of cyclic loading and retightening on reverse torque value in external and internal implants.

    PubMed

    Cho, Woong-Rae; Huh, Yoon-Hyuk; Park, Chan-Jin; Cho, Lee-Ra

    2015-08-01

    The aim of this study was to evaluate the effect of cyclic loading and screw retightening on reverse torque value (RTV) in external and internal type implants. Cement-retained abutments were connected with 30 Ncm torque to external and internal type implants. Experimental groups were classified according to implant connection type and retightening/loading protocol. In groups with no retightening, RTV was evaluated after cyclic loading for 100,000 cycles. In groups with retightening, RTV was measured after 3, 10, 100 cycles as well as every 20,000 cycles until 100,000 cycles of loading. Every group showed decreased RTV after cyclic loading. Before and after cyclic loading, external type implants had significantly higher RTVs than internal type implants. In external type implants, retightening did not affect the decrease in RTV. In contrast, retightening 5 times and retightening after 10 cycles of dynamic loading was effective for maintaining RTV in internal type implants. Retightening of screws is more effective in internal type implants than external type implants. Retightening of screws is recommended in the early stage of functional loading.

  17. In Vivo Response of Laser Processed Porous Titanium Implants for Load-Bearing Implants.

    PubMed

    Bandyopadhyay, Amit; Shivaram, Anish; Tarafder, Solaiman; Sahasrabudhe, Himanshu; Banerjee, Dishary; Bose, Susmita

    2017-01-01

    Applications of porous metallic implants to enhance osseointegration of load-bearing implants are increasing. In this work, porous titanium implants, with 25 vol.% porosity, were manufactured using Laser Engineered Net Shaping (LENS™) to measure the influence of porosity towards bone tissue integration in vivo. Surfaces of the LENS™ processed porous Ti implants were further modified with TiO 2 nanotubes to improve cytocompatibility of these implants. We hypothesized that interconnected porosity created via additive manufacturing will enhance bone tissue integration in vivo. To test our hypothesis, in vivo experiments using a distal femur model of male Sprague-Dawley rats were performed for a period of 4 and 10 weeks. In vivo samples were characterized via micro-computed tomography (CT), histological imaging, scanning electron microscopy, and mechanical push-out tests. Our results indicate that porosity played an important role to establish early stage osseointegration forming strong interfacial bonding between the porous implants and the surrounding tissue, with or without surface modification, compared to dense Ti implants used as a control.

  18. In vivo response of laser processed porous titanium implants for load-bearing implants

    PubMed Central

    Bandyopadhyay, Amit; Shivaram, Anish; Tarafder, Solaiman; Sahasrabudhe, Himanshu; Banerjee, Dishary; Bose, Susmita

    2016-01-01

    Applications of porous metallic implants to enhance osseointegration of load-bearing implants are increasing. In this work, porous titanium implants, with 25 volume% porosity, were manufactured using Laser Engineered Net Shaping (LENS™) to measure the influence of porosity towards bone tissue integration in vivo. Surfaces of the LENS™ processed porous Ti implants were further modified with TiO2 nanotubes to improve cytocompatibility of these implants. We hypothesized that interconnected porosity created via additive manufacturing will enhance bone tissue integration in vivo. To test our hypothesis, in vivo experiments using a distal femur model of male Sprague-Dawley rats were performed for a period of 4 and 10 weeks. In vivo samples were characterized via micro-computed tomography (CT), histological imaging, scanning electron microscopy, and mechanical push-out tests. Our results indicate that porosity played an important role to establish early stage osseointegration forming strong interfacial bonding between the porous implants and the surrounding tissue, with or without surface modification, compared to dense Ti implants used as a control. PMID:27307009

  19. Technique of after-loading interstitial implants.

    PubMed

    Syed, A M; Feder, B H

    1977-01-01

    Interstitial implants are either removable or permanent (and occasionally a combination of both). Permanent implants are generally utilized where tumors are not accessible enough to permit easy removal of sources or where accurate source distribution is less critical. They are useful for cancers of the lung, pancreas, prostate, bladder, lymph nodes, etc. Radon and gold-198 have been largely replaced by iodine-125. Our major interests are in the removable after-loading iridium-192 implant techniques. Template (steel guide) and non-template (plastic tube) techniques are utilized. Templates are preferred where the tumor volume can only be approached from one side and where accurate positioning of sources would otherwise be difficult. They are useful for cancers of the cervix, vagina, urethra, and rectum. Non-template (plastic tube) techniques are preferred where the tumor volume can be approached from at least two sides and where templates are either not feasible or not essential for accurate positioning of sources. The single needle non-template approach is useful for cancers of lip, nodes, and breast (plastic button) and for cancers of the oral cavity and oropharynx (gold button). The paired needle non-template approach is useful for cancers of the gum, retromolar trigone, and base of tongue (loop technique) and for cancers of the palate (arch technique). Procedures for each technique are described in detail.

  20. Barriers to early cochlear implantation.

    PubMed

    Dettman, Shani; Choo, Dawn; Dowell, Richard

    2016-01-01

    Identify variables associated with paediatric access to cochlear implants (CIs). Part 1. Trends over time for age at CI surgery (N = 802) and age at hearing aid (HA) fitting (n = 487) were examined with regard to periods before, during, and after newborn hearing screening (NHS). Part 2. Demographic factors were explored for 417 children implanted under 3 years of age. Part 3. Pre-implant steps for the first 20 children to receive CIs under 12 months were examined. Part 1. Age at HA fitting and CI surgery reduced over time, and were associated with NHS implementation. Part 2. For children implanted under 3 years, earlier age at HA fitting and higher family socio-economic status were associated with earlier CI. Progressive hearing loss was associated with later CIs. Children with a Connexin 26 diagnosis received CIs earlier than children with a premature / low birth weight history. Part 3. The longest pre-CI steps were Step 1: Birth to diagnosis/identification of hearing loss (mean 16.43 weeks), and Step 11: MRI scans to implant surgery (mean 15.05 weeks) for the first 20 infants with CIs under 12 months. NHS implementation was associated with reductions in age at device intervention in this cohort.

  1. Influence of controlled immediate loading and implant design on peri-implant bone formation.

    PubMed

    Vandamme, Katleen; Naert, Ignace; Geris, Liesbet; Vander Sloten, Jozef; Puers, Robert; Duyck, Joke

    2007-02-01

    Tissue formation at the implant interface is known to be sensitive to mechanical stimuli. The aim of the study was to compare the bone formation around immediately loaded versus unloaded implants in two different implant macro-designs. A repeated sampling bone chamber with a central implant was installed in the tibia of 10 rabbits. Highly controlled loading experiments were designed for a cylindrical (CL) and screw-shaped (SL) implant, while the unloaded screw-shaped (SU) implant served as a control. An F-statistic model with alpha=5% determined statistical significance. A significantly higher bone area fraction was observed for SL compared with SU (p<0.0001). The mineralized bone fraction was the highest for SL and significantly different from SU (p<0.0001). The chance that osteoid- and bone-to-implant contact occurred was the highest for SL and significantly different from SU (p<0.0001), but not from CL. When bone-to-implant contact was observed, a loading (SL versus SU: p=0.0049) as well as an implant geometry effect (SL versus CL: p=0.01) was found, in favour of the SL condition. Well-controlled immediate implant loading accelerates tissue mineralization at the interface. Adequate bone stimulation via mechanical coupling may account for the larger bone response around the screw-type implant compared with the cylindrical implant.

  2. Immediate Versus Delayed Loading of Implant for Replacement of Missing Mandibular First Molar: A Randomized Prospective Six Years Clinical Study.

    PubMed

    Chidagam, Prudhvi Raj Lakshmi Venkata; Gande, Vijaya Chandra; Yadlapalli, Sravanthi; Venkata, Ramani Yarlagadda; Kondaka, Sudheer; Chedalawada, Sravya

    2017-04-01

    Emergence of dental implants made the replacement of missing tooth easy. During the early days of introduction, implants were loaded three to six months after implant insertion, but understanding of healing cascade and improved production technology has changed the phase of restoration from delayed to immediate loading. To evaluate and compare the clinical outcome of immediate and delayed loaded implant supported prosthesis for missing mandibular first molar. The objectives were bleeding on probing, probing depth, implant mobility, marginal bone level and peri-implant radiolucency were evaluated during follow up period. Twenty patients were included in this study who were in the need of fixed implant supported prosthesis for missing mandibular first molar. Single tooth implant with immediate loading done within two days of implant insertion in one group and another group were loaded after three months of implant insertion. These groups were evaluated clinically and radiographically over a period of 72 months after loading using Wilcoxon matched pairs test and Mann-Whitney U test. The study consists of 14 male and six female patients with the age range of 19 to 31 years. There was no bleeding on probing and probing depth remained well within the normal range even after 72 months of loading among both the groups. Minimal marginal bone loss observed with no mobility and peri-implant radiolucency. Implant supported prosthesis for missing mandibular first molar with immediate loading can be used as a successful treatment modality. It reduces treatment time, provides early function and prevents undue migration of adjacent tooth. Immediate loading showed similar clinical and radiographic results as that of delayed loading, indicating it as an equally efficient technique for implant supported prosthesis.

  3. Comparison of load distribution for implant overdenture attachments.

    PubMed

    Porter, Joseph A; Petropoulos, Vicki C; Brunski, John B

    2002-01-01

    The aim of this study was to compare the force and moment distributions that develop on different implant overdenture attachments when vertical compressive forces are applied to an implant-retained overdenture. The following attachments were examined: Nobel Biocare bar and clip (NBC), Nobel Biocare standard ball (NSB), Nobel Biocare 2.25-mm-diameter ball (NB2), Zest Anchor Advanced Generation (ZAAG), Sterngold ERA white (SEW), Sterngold ERA orange (SEO), Compliant Keeper System with titanium shims (CK-Ti), Compliant Keeper System with black nitrile 2SR90 sleeve rings (CK-70), and Compliant Keeper System with clear silicone 2SR90 sleeve rings (CK-90). The attachments were tested using custom strain-gauged abutments and 2 Brånemark System implants placed in a test model. Each attachment type had one part embedded in a denture-like housing and the other part (the abutment) screwed into the implants. Compressive static loads of 100 N were applied (1) bilaterally, over the distal midline (DM); (2) unilaterally, over the right implant (RI); (3) unilaterally, over the left implant (LI); and (4) between implants in the mid-anterior region (MA). Both the force and bending moment on each implant were recorded for each loading location and attachment type. Results were analyzed using 2-way analysis of variance and the Duncan multiple-range test. Both loading location and attachment type were statistically significant factors (P < .05). In general, the force and moment on an implant were greater when the load was applied directly over the implant or at MA. While not significant at every loading location, the largest implant forces tended to occur with ZAAG attachments; the smallest were found with the SEW, the SEO, the NSB, the CK-70, and the CK-90. Typically, higher moments existed for NBC and ZAAG, while lower moments existed for SEW, SEO, NSB, CK-90, and CK-70. For different loading locations, significant differences were found among the different overdenture attachment

  4. A comparative study of the effectiveness of early and delayed loading of short tissue-level dental implants with hydrophilic surfaces placed in the posterior section of the mandible-A preliminary study.

    PubMed

    Makowiecki, Arkadiusz; Botzenhart, Ute; Seeliger, Julia; Heinemann, Friedhelm; Biocev, Peter; Dominiak, Marzena

    2017-07-01

    The objective of the present study was to compare the primary and secondary stability of tissue-level short dental titanium implants with polished necks and hydrophilic surfaces of two different designs and manufacturers. The first implant system used (SPI ® ELEMENT RC INICELL titanium implants, Thommen Medical AG, Grenchen, Switzerland), allowed functional loading 6 weeks after its placement, whereas the second implant system (RN SLActiv ® tissue-level titanium implants, Straumann GmbH, Fribourg, Germany), was loaded after 15 weeks. The degree of primary and secondary stability was determined using an Osstell ISQ measuring device. Marginal bone loss (MBL) was evaluated radiographically 12 and 24 weeks after implantation and the Wachtel's healing index as well as the patient's satisfaction with the treatment was registered on a VAS scale. The intergroup comparison revealed significant differences in terms of primary stability as well as differences in MBL 3 months after the procedure, but no significant differences could be found after 6 months and for secondary stability. The primary stability was significantly higher for Thommen ® compared to Straumann ® implants. Insertion of short dental implants with a hydrophilic conditioned surface significantly shortens patient treatment time. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. Bone healing response in cyclically loaded implants: Comparing zero, one, and two loading sessions per day.

    PubMed

    de Barros E Lima Bueno, Renan; Dias, Ana Paula; Ponce, Katia J; Wazen, Rima; Brunski, John B; Nanci, Antonio

    2018-05-31

    When bone implants are loaded, they are inevitably subjected to displacement relative to bone. Such micromotion generates stress/strain states at the interface that can cause beneficial or detrimental sequels. The objective of this study is to better understand the mechanobiology of bone healing at the tissue-implant interface during repeated loading. Machined screw shaped Ti implants were placed in rat tibiae in a hole slightly bigger than the implant diameter. Implants were held stable by a specially-designed bone plate that permits controlled loading. Three loading regimens were applied, (a) zero loading, (b) one daily loading session of 60 cycles with an axial force of 1.5 N/cycle for 7 days, and (c) two such daily sessions with the same axial force also for 7 days. Finite element analysis was used to characterize the mechanobiological conditions produced by the loading sessions. After 7 days, the implants with surrounding interfacial tissue were harvested and processed for histological, histomorphometric and DNA microarray analyses. Histomorphometric analyses revealed that the group subjected to repeated loading sessions exhibited a significant decrease in bone-implant contact and increase in bone-implant distance, as compared to unloaded implants and those subjected to only one loading session. Gene expression profiles differed during osseointegration between all groups mainly with respect to inflammatory and unidentified gene categories. The results indicate that increasing the daily cyclic loading of implants induces deleterious changes in the bone healing response, most likely due to the accumulation of tissue damage and associated inflammatory reaction at the bone-implant interface. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  6. Loading capacity of zirconia implant supported hybrid ceramic crowns.

    PubMed

    Rohr, Nadja; Coldea, Andrea; Zitzmann, Nicola U; Fischer, Jens

    2015-12-01

    Recently a polymer infiltrated hybrid ceramic was developed, which is characterized by a low elastic modulus and therefore may be considered as potential material for implant supported single crowns. The purpose of the study was to evaluate the loading capacity of hybrid ceramic single crowns on one-piece zirconia implants with respect to the cement type. Fracture load tests were performed on standardized molar crowns milled from hybrid ceramic or feldspar ceramic, cemented to zirconia implants with either machined or etched intaglio surface using four different resin composite cements. Flexure strength, elastic modulus, indirect tensile strength and compressive strength of the cements were measured. Statistical analysis was performed using two-way ANOVA (p=0.05). The hybrid ceramic exhibited statistically significant higher fracture load values than the feldspar ceramic. Fracture load values and compressive strength values of the respective cements were correlated. Highest fracture load values were achieved with an adhesive cement (1253±148N). Etching of the intaglio surface did not improve the fracture load. Loading capacity of hybrid ceramic single crowns on one-piece zirconia implants is superior to that of feldspar ceramic. To achieve maximal loading capacity for permanent cementation of full-ceramic restorations on zirconia implants, self-adhesive or adhesive cements with a high compressive strength should be used. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  7. Prospective randomized clinical trial of hydrophilic tapered implant placement at maxillary posterior area: 6 weeks and 12 weeks loading

    PubMed Central

    2016-01-01

    PURPOSE Early loading of implant can be determined by excellent primary stability and characteristic of implant surface. The implant system with recently improved surface can have load application 4-6 weeks after installing in maxilla and mandible. This study evaluated the effect of healing period to the stability of hydrophilic tapered-type implant at maxillary posterior area. MATERIALS AND METHODS This study included 30 patients treated by hydrophilic tapered-type implants (total 41 implants at maxilla) and classified by two groups depending on healing period. Group 1 (11 patients, 15 implants) was a control group and the healing period was 12 weeks, and Group 2 (19 patients, 26 implants) was test group and the healing period was 6 weeks. Immediately after implant placement, at the first impression taking, implant stability was measured using Osstell Mentor. The patients also took periapical radiographs after restoration delivery, 12 months after restoration and final followup period. The marginal bone loss around the implants was measured using the periapical radiographs. RESULTS All implants were survived and success rate was 97.56%. The marginal bone loss was less than 1mm after 1 year postoperatively except the one implant. The stabilities of the implants were not correlated with age, healing period until loading, insertion torque (IT), the diameter of fixture and the location of implant. Only the quality of bone in group 2 (6 week) was correlated with the stability of implant. CONCLUSION Healing period of 6 weeks can make the similar clinical prognosis of implants to that of healing period of 12 weeks if bone quality is carefully considered in case of early loading. PMID:27826390

  8. Osseous adaptation to continuous loading of rigid endosseous implants

    NASA Technical Reports Server (NTRS)

    Roberts, W. E.; Smith, R. K.; Mozsary, P. G.; Zilberman, Y.; Smith, R. S.

    1984-01-01

    The effect of loading on etched Ti implants in the femurs of young (3 mo) and adult (6 mo) rabbits is investigated experimentally. The results are presented in photographs, fluorescence and polarization micrographs, radiographs, and drawings and discussed. Implantation is followed by formation of coarse woven bone within 3 d and mature lamellar bone by 6 wks, with nonspecific subperiosteal bony hypertrophy in the young rabbits only. Spring loading at 100 g produces spontaneous spiral-type fractures when applied immediately, but the implants remain rigid when loads are applied after 6-12 wks of healing. The mechanisms of bone formation involved are examined, and the potential of endosseous implants as anchors in orthodontics or dentofacial-orthopedics is confirmed.

  9. Clinical evaluation of immediate loading of titanium orthodontic implants

    PubMed Central

    Chopra, S.S.; Chakranarayan, A.

    2015-01-01

    Background Skeletal anchorage using dental implants, miniplates, miniscrews and microscrews provides an absolute anchorage for tooth movement. Miniscrew and microscrew implants have many benefits such as ease of placement and removal and immediate orthodontic force application. Methods Fifteen subjects in the permanent dentition with an overjet ≥6 mm received treatment with the 0.018-inch pre-adjusted edgewise appliance system (Roth prescription) and extraction of all first premolars. Titanium orthodontic implants were placed in both the upper quadrants and were immediately loaded with elastic chain from the implant head to the sectional arch wire. Result The overall success rate of immediate loaded titanium orthodontic micro implants (OMI) in the present study was 83.33%, with a mean chairside time of 15.33 min of placing two implants in each patient. Peri-implant inflammation was the only complication observed. Most failures were in the initial part of the study. There was no significant difference in the success rate of implants based on sex, side of placement (right or left) and type of malocclusion. Conclusion The OMIs used in the present study proved to be effective and well tolerated in producing immediate orthodontic anchorage for the retraction. PMID:25859080

  10. Optimally oriented grooves on dental implants improve bone quality around implants under repetitive mechanical loading.

    PubMed

    Kuroshima, Shinichiro; Nakano, Takayoshi; Ishimoto, Takuya; Sasaki, Muneteru; Inoue, Maaya; Yasutake, Munenori; Sawase, Takashi

    2017-01-15

    The aim was to investigate the effect of groove designs on bone quality under controlled-repetitive load conditions for optimizing dental implant design. Anodized Ti-6Al-4V alloy implants with -60° and +60° grooves around the neck were placed in the proximal tibial metaphysis of rabbits. The application of a repetitive mechanical load was initiated via the implants (50N, 3Hz, 1800 cycles, 2days/week) at 12weeks after surgery for 8weeks. Bone quality, defined as osteocyte density and degree of biological apatite (BAp) c-axis/collagen fibers, was then evaluated. Groove designs did not affect bone quality without mechanical loading; however, repetitive mechanical loading significantly increased bone-to-implant contact, bone mass, and bone mineral density (BMD). In +60° grooves, the BAp c-axis/collagen fibers preferentially aligned along the groove direction with mechanical loading. Moreover, osteocyte density was significantly higher both inside and in the adjacent region of the +60° grooves, but not -60° grooves. These results suggest that the +60° grooves successfully transmitted the load to the bone tissues surrounding implants through the grooves. An optimally oriented groove structure on the implant surface was shown to be a promising way for achieving bone tissue with appropriate bone quality. This is the first report to propose the optimal design of grooves on the necks of dental implants for improving bone quality parameters as well as BMD. The findings suggest that not only BMD, but also bone quality, could be a useful clinical parameter in implant dentistry. Although the paradigm of bone quality has shifted from density-based assessments to structural evaluations of bone, clarifying bone quality based on structural bone evaluations remains challenging in implant dentistry. In this study, we firstly demonstrated that the optimal design of dental implant necks improved bone quality defined as osteocytes and the preferential alignment degree of biological

  11. The effect of varying implant position in immediately loaded implant-supported mandibular overdentures.

    PubMed

    Shaarawy, Mohammed A; Aboelross, Ehab M

    2013-06-01

    This study was carried out to evaluate the effect of varying implant position in immediately loaded implant-supported mandibular overdentures on peri-implant bone density, muscle activity, and patient satisfaction. Fourteen completely edentulous patients were selected for the study. After complete denture construction, patients were divided into 2 equal groups. Four dental implants were installed bilaterally in the interforaminal region in the first group, while in the second group, 4 dental implants were inserted bilaterally: 2 in the interforaminal region and 2 in the first molar area. Immediately after suturing, telescopic abutments were screwed to the implants, and the retaining caps were picked up into the fitting surface of the lower denture, which was delivered to the patient. Patients were recalled for radiographic bone density evaluation just after denture delivery and then at 3, 6, and 12 months thereafter. Muscle activities of masseter and temporalis muscles as well as patient satisfaction were also evaluated. The results of the study showed a high success rate approximating 98.2% of the immediately loaded implants. The electromyographic (EMG) records of both muscles in group 1 were significantly higher during chewing hard food after 3 months compared with group 2 (P < .05). Bone density changes were comparable in the 2 groups except at the end of the follow-up period, when group 2 showed a significant increase in peri-implant bone density values of the posteriorly placed implants compared with group 1 (P < .05). From the results of this study, it may be concluded that wide distribution of immediately loaded implants used for supporting mandibular overdentures through posterior placement beyond the interforaminal area results in a favorable response in terms of increased peri-implant bone density as well as decreased EMG activity of masseter and temporalis muscles.

  12. Starflo glaucoma implant: early experience in Hungary

    PubMed Central

    István, Cseke; Péter, Vámosi; Mária, Bausz

    2016-01-01

    Aim: To present the early experience with the implantation technique, safety and efficiency of STARflo™ device for open angle glaucoma (OAG). Methods: referring intra- and postoperative clinical experience with a series of seven cases in three glaucoma centers in Hungary. Results: No intraoperative complications were observed. Postoperative inflammatory signs disappeared rapidly. The mean IOP reduction was from 27,6 ± 5,0 mmHg to 18,9±3,4 mmHg (32% reduction/ patient) at six months postoperatively. Conclusion: STARflo™ implant was safe and (except for one case with neovascular glaucoma) effective in our cases. The learning curve for experienced anterior segment surgeons was short. PMID:27220226

  13. Implant Mandibular Overdentures Retained by Immediately Loaded Implants: A 1-Year Randomized Trial Comparing the Clinical and Radiographic Outcomes Between Mini Dental Implants and Standard-Sized Implants.

    PubMed

    Zygogiannis, Kostas; Aartman, Irene Ha; Parsa, Azin; Tahmaseb, Ali; Wismeijer, Daniel

    The aim of this 1-year randomized trial was to evaluate and compare the clinical and radiographic performance of four immediately loaded mini dental implants (MDIs) and two immediately loaded standard-sized tissue-level (STL) implants, placed in the interforaminal region of the mandible and used to retain mandibular overdentures (IODs) in completely edentulous patients. A total of 50 completely edentulous patients wearing conventional maxillary dentures and complaining about insufficient retention of their mandibular dentures were divided into two groups; 25 patients received four MDIs and 25 patients received two STL implants. The marginal bone loss (MBL) at the mesial and distal sides of each implant was assessed by means of standardized intraoral radiographs after a period of 1 year. Implant success and survival rates were also calculated. Immediate loading was possible for all patients in the first group. In the second group, an immediate loading protocol could not be applied for 10 patients. These patients were treated with a delayed loading protocol. A mean MBL of 0.42 ± 0.56 mm for the MDIs and 0.54 ± 0.49 mm for the immediately loaded STL implants was recorded at the end of the evaluation period. There was no statistically significant difference between the MDIs and the immediately loaded STL implants. Two MDIs failed, resulting in a survival rate of 98%. The success rate was 91%. For the immediately loaded conventional implants, the survival rate was 100% and the success rate 96.7% after 1 year of function. However, in 10 patients, the immediate loading protocol could not be followed. Considering the limitations of this short-term clinical study, immediate loading of four unsplinted MDIs or two splinted STL implants to retain mandibular overdentures seems to be a feasible treatment option. The marginal bone level changes around the MDIs were well within the clinically acceptable range.

  14. Simulation of peri-implant bone healing due to immediate loading in dental implant treatments.

    PubMed

    Chou, Hsuan-Yu; Müftü, Sinan

    2013-03-15

    The goal of this work was to investigate the role of immediate loading on the peri-implant bone healing in dental implant treatments. A mechano-regulatory tissue differentiation model that takes into account the stimuli through the solid and the fluid components of the healing tissue, and the diffusion of pluripotent stem cells into the healing callus was used. A two-dimensional axisymmetric model consisting of a dental implant, the healing callus tissue and the host bone tissue was constructed for the finite element analysis. Poroelastic material properties were assigned to the healing callus and the bone tissue. The effects of micro-motion, healing callus size, and implant thread design on the length of the bone-to-implant contact (BIC) and the bone volume (BV) formed in the healing callus were investigated. In general, the analysis predicted formation of a continuous layer of soft tissue along the faces of the implant which are parallel to the loading direction. This was predicted to be correlated with the high levels of distortional strain transferred through the solid component of the stimulus. It was also predicted that the external threads on the implant, redistribute the interfacial load, thus help reduce the high distortional stimulus and also help the cells to differentiate to bone tissue. In addition, the region underneath the implant apex was predicted to experience high fluid stimulus that results in the development of soft tissue. The relationship between the variables considered in this study and the outcome measures, BV and BIC, was found to be highly nonlinear. A three-way analysis of variance (ANOVA) of the results was conducted and it showed that micro-motion presents the largest hindrance to bone formation during healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Immediate loading of implants in the aesthetic zone: comparison between two placement timings.

    PubMed

    Carini, Fabrizio; Longoni, Salvatore; Pisapia, Valeria; Francesconi, Manuel; Saggese, Vito; Porcaro, Gianluca

    2014-01-01

    for the evaluation of aesthetic outcome, immediate/early placement and loading of a single TSA® Advance, Phibo® may be considered a valuable and predictable option in terms of implant success as well as hard and soft tissue stability.

  16. Long-Term Survival of Dental Implants with Different Prosthetic Loading Times in Healthy Patients: A 5-Year Retrospective Clinical Study.

    PubMed

    Muelas-Jiménez, M Isabel; Olmedo-Gaya, Maria Victoria; Manzano-Moreno, Francisco J; Reyes-Botella, Candela; Vallecillo-Capilla, Manuel

    2017-02-01

    To compare survival rates among dental implants restored with immediate, early, and conventional loading protocols, also comparing between maxillary and mandibular implants, and to evaluate the influence of implant length and diameter and the type of prosthesis on treatment outcomes. This retrospective cohort study initially included all 52 patients receiving dental implants between July 2006 and February 2008 at a private oral surgery clinic in Granada (Southern Spain). Clinical and radiographic examinations were performed, including periapical or panoramic radiographs, and incidences during completion of the restoration were recorded at 1 week, 3 months, 6 months, and at 1, 2, 3, 4, and 5 years. After a 5-year follow-up, 1 patient had died, 3 were lost to follow-up, and 6 required grafting before implant placement; therefore, the final study sample comprised 42 patients with 164 implants. Variables associated with the survival/failure of the restoration were: number of implants (higher failure rate with fewer implants), bone type (higher failure rate in type III or IV bone), and type of prosthesis (higher failure rate with single crowns). No significant association was found in univariate or multivariate analyses between survival rate and the loading protocol, implant length or diameter, or maxillary/mandibular location. Immediate occlusal loading, immediate provisionalization without occlusal loading, and early loading are viable treatment options with similar survival rates to those obtained with conventional loading. Bone quality and number of implants per patient were the most influential factors. © 2015 by the American College of Prosthodontists.

  17. Influence of immediate loading on provisional restoration in dental implant stability

    NASA Astrophysics Data System (ADS)

    Ikbal, M.; Odang, R. W.; Indrasari, M.; Dewi, R. S.

    2017-08-01

    The success of dental implant treatment is determined by the primary stability at placement. One factor that could influence this stability is occlusal loading through provisional restoration. Two types of loading protocols are usually used: immediate and delayed loading. However, some controversies remain about the influence of occlusal loading on implant stability. Therefore, the influence of immediate loading on implant stability must be studied. An animal study was conducted by placing nine dental implants in the mandibular jaw of three Macaca fascicularis. Provisional restorations with various occlusal contacts (no, light, and normal contact) were placed on the implant. The implant stability was measured using the Ostell ISQ three times: immediately (baseline) and at the first and second months after implant placement. The implant stability between implants with no and normal occlusal contact as well as light and normal occlusal contact showed significant differences (p < 0.05) at the first and second months after implant placement. However, no significant increase (p > 0.05) in implant stability was seen at the baseline and the first and second months after implant placement for all occlusal contact groups. Immediate loading influenced the implant stability, and provisional restoration of implant without occlusal contact showed the highest implant stability.

  18. Immediate occlusal loading of NanoTite PREVAIL implants: a prospective 1-year clinical and radiographic study.

    PubMed

    Ostman, Pär-Olov; Wennerberg, Ann; Albrektsson, Tomas

    2010-03-01

    Recently, a new implant surface texture, featuring application of nanometer-scale calcium phosphate has been shown to enhance early bone fixation and formation in preclinical studies and in human histomorphometric studies, which may be beneficial in immediate loading situations. The purpose of the present prospective clinical study was to, during 1 year, clinically and radiographically evaluate a nanometer scale surface modified implant placed for immediate loading of fixed prostheses in both maxillary and mandibular regions. Thirty-five out of 38 patients who needed implant treatment and met inclusion criteria agreed to participate in the study and were consecutively enrolled. Surgical implant placement requirements consisted of a final torque of a least 25 Ncm prior to final seating and an implant stability quotient above 55. A total of 102 NanoTite PREVAIL (NTP) implants (BIOMET 3i, Palm Beach Gardens, FL, USA) (66 maxillary and 36 mandibular) were placed by one investigator, and the majority of these were placed in posterior regions (65%) and in soft bone (69%). A total of 44 prosthetic constructions were evaluated consisting of 14 single-tooth restorations, 26 fixed partial dentures, and four complete fixed restorations. All provisional constructions were delivered within 1 hour, and the final constructions placed after 4 months. Implants were monitored for clinical and radiographic outcomes at follow-up examinations scheduled for 3, 6, and 12 months. Of the 102 study implants, one implant failed. The simple cumulative survival rate value at 1 year was 99.2%. The average marginal bone resorption was 0.37 mm (SD 0.39) during the first year in function. According to the success criteria of Albrektsson and Zarb, success grade 1 was found with 93% of the implants. Although limited to the short follow-up, immediate loading of NanoTite Prevail implants seems to be a viable option in implant rehabilitation, at least when a good initial fixation is achieved.

  19. Numerical investigation of bone remodelling around immediately loaded dental implants using sika deer (Cervus nippon) antlers as implant bed.

    PubMed

    He, Yun; Hasan, Istabrak; Keilig, Ludger; Fischer, Dominik; Ziegler, Luisa; Abboud, Marcus; Wahl, Gerhard; Bourauel, Christoph

    2018-03-01

    This study combines finite element method and animal studies, aiming to investigate tissue remodelling processes around dental implants inserted into sika deer antler and to develop an alternative animal consuming model for studying bone remodelling around implants. Implants were inserted in the antlers and loaded immediately via a self-developed loading device. After 3, 4, 5 and 6 weeks, implants and surrounding tissue were taken out. Specimens were scanned by μCT scanner and finite element models were generated. Immediate loading and osseointegration conditions were simulated at the implant-tissue interface. A vertical force of 10 N was applied on the implant. During the healing time, density and Young's modulus of antler tissue around the implant increased significantly. For each time point, the values of displacement, stresses and strains in the osseointegration model were lower than those of the immediate loading model. As the healing time increased, the displacement of implants was reduced. The 3-week immediate loading model (9878 ± 1965 μstrain) illustrated the highest strains in the antler tissue. Antler tissue showed similar biomechanical properties as human bone in investigating the bone remodelling around implants, therefore the use of sika deer antler model is a promising alternative in implant biomechanical studies.

  20. Finite element analysis of different loading conditions for implant-supported overdentures supported by conventional or mini implants.

    PubMed

    Solberg, K; Heinemann, F; Pellikaan, P; Keilig, L; Stark, H; Bourauel, C; Hasan, I

    2017-05-01

    The effect of implants' number on overdenture stability and stress distribution in edentulous mandible, implants and overdenture was numerically investigated for implant-supported overdentures. Three models were constructed. Overdentures were connected to implants by means of ball head abutments and rubber ring. In model 1, the overdenture was retained by two conventional implants; in model 2, by four conventional implants; and in model 3, by five mini implants. The overdenture was subjected to a symmetrical load at an angle of 20 degrees to the overdenture at the canine regions and vertically at the first molars. Four different loading conditions with two total forces (120, 300 N) were considered for the numerical analysis. The overdenture displacement was about 2.2 times higher when five mini implants were used rather than four conventional implants. The lowest stress in bone bed was observed with four conventional implants. Stresses in bone were reduced by 61% in model 2 and by 6% in model 3 in comparison to model 1. The highest stress was observed with five mini implants. Stresses in implants were reduced by 76% in model 2 and 89% increased in model 3 compared to model 1. The highest implant displacement was observed with five mini implants. Implant displacements were reduced by 29% in model 2, and increased by 273% in model 3 compared to model 1. Conventional implants proved better stability for overdenture than mini implants. Regardless the type and number of implants, the stress within the bone and implants are below the critical limits.

  1. Immediate loading of subcrestally placed dental implants in anterior and premolar sites.

    PubMed

    Henningsen, Anders; Smeets, Ralf; Köppen, Kai; Sehner, Susanne; Kornmann, Frank; Gröbe, Alexander; Heiland, Max; Gerlach, Till

    2017-11-01

    Immediate loading of dental implants has been evolving into an appropriate procedure for the treatment of partially edentulous jaws. The purpose of this study was to evaluate the clinical success and radiological outcome of immediately and delayed loaded dental implants in anterior and premolar sites. In this retrospective study, data of 163 individuals requiring tooth removal with subsequent implant placement in anterior and premolar sites were analyzed. Implants were immediately loaded by provisional acrylic resin bridges or loaded with delay. Implants were followed up annually for up to 9 years including intraoral radiographs. A total of 285 implants in 163 patients were placed. 218 implants were immediately loaded and 67 implants with delay. Fifteen implants failed during the follow-up period resulting in survival rates of 94.5% for immediate loading and 95.5% for delayed loading. After an initial decrease of 0.3 mm in the first 12 months the marginal bone level remained stable. No statistically significant differences were found in marginal bone loss between immediately and delayed loaded implants (P = 0.518, 95% CI). Within the limits of this study, immediate loading of immediately subcrestally placed dental implants in anterior and premolar sites is a reliable treatment option for dental rehabilitation. Copyright © 2017 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  2. Implant-bone interface stress distribution in immediately loaded implants of different diameters: a three-dimensional finite element analysis.

    PubMed

    Ding, Xi; Zhu, Xing-Hao; Liao, Sheng-Hui; Zhang, Xiu-Hua; Chen, Hong

    2009-07-01

    To establish a 3D finite element model of a mandible with dental implants for immediate loading and to analyze stress distribution in bone around implants of different diameters. Three mandible models, embedded with thread implants (ITI, Straumann, Switzerland) with diameters of 3.3, 4.1, and 4.8 mm, respectively, were developed using CT scanning and self-developed Universal Surgical Integration System software. The von Mises stress and strain of the implant-bone interface were calculated with the ANSYS software when implants were loaded with 150 N vertical or buccolingual forces. When the implants were loaded with vertical force, the von Mises stress concentrated on the mesial and distal surfaces of cortical bone around the neck of implants, with peak values of 25.0, 17.6 and 11.6 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains (5854, 4903, 4344 muepsilon) were located on the buccal cancellous bone around the implant bottom and threads of implants. The stress and strain were significantly lower (p < 0.05) with the increased diameter of implant. When the implants were loaded with buccolingual force, the peak von Mises stress values occurred on the buccal surface of cortical bone around the implant neck, with values of 131.1, 78.7, and 68.1 MPa for 3.3, 4.1, and 4.8 mm diameters, respectively, while the maximum strains occurred on the buccal surface of cancellous bone adjacent to the implant neck, with peak values of 14,218, 12,706, and 11,504 microm, respectively. The stress of the 4.1-mm diameter implants was significantly lower (p < 0.05) than those of 3.3-mm diameter implants, but not statistically different from that of the 4.8 mm implant. With an increase of implant diameter, stress and strain on the implant-bone interfaces significantly decreased, especially when the diameter increased from 3.3 to 4.1 mm. It appears that dental implants of 10 mm in length for immediate loading should be at least 4.1 mm in diameter, and uniaxial

  3. Assessment of different polymers and drug loads for fused deposition modeling of drug loaded implants.

    PubMed

    Kempin, Wiebke; Franz, Christian; Koster, Lynn-Christine; Schneider, Felix; Bogdahn, Malte; Weitschies, Werner; Seidlitz, Anne

    2017-06-01

    The 3D printing technique of fused deposition modeling® (FDM) has lately come into focus as a potential fabrication technique for pharmaceutical dosage forms and medical devices that allows the preparation of delivery systems with nearly any shape. This is particular promising for implants administered at application sites with a high anatomical variability where an individual shape adaption appears reasonable. In this work different polymers (Eudragit®RS, polycaprolactone (PCL), poly(l-lactide) (PLLA) and ethyl cellulose (EC)) were evaluated with respect to their suitability for FDM of drug loaded implants and their drug release behaviour was evaluated. The fluorescent dye quinine was used as a model drug to visualize drug distribution in filaments and implants. Quinine loaded filaments were produced by solvent casting and subsequent hot melt extrusion (HME) and model implants were printed as hollow cylinders using a standard FDM printer. Parameters were found at which model implants (hollow cylinders, outer diameter 4-5mm, height 3mm) could be produced from all tested polymers. The drug release which was examined by incubation of the printed implants in phosphate buffered saline solution (PBS) pH 7.4 was highly dependent on the used polymer. The fastest relative drug release of approximately 76% in 51days was observed for PCL and the lowest for Eudragit®RS and EC with less than 5% of quinine release in 78 and 100days, respectively. For PCL further filaments were prepared with different quinine loads ranging from 2.5% to 25% and thermal analysis proved the presence of a solid dispersion of quinine in the polymer for all tested concentrations. Increasing the drug load also increased the overall percentage of drug released to the medium since nearly the same absolute amount of quinine remained trapped in PCL at the end of drug release studies. This knowledge is valuable for future developments of printed implants with a desired drug release profile that might be

  4. Immediate loading of titanium hexed screw-type implants in the edentulous patient: case report.

    PubMed

    Calvo, M P; Muller, E; Garg, A K

    2000-01-01

    Histologic and histomorphometric studies in both animals and humans have shown that more rapid and greater bone-to-implant contact can be achieved with implants that incorporate certain surface characteristics compared with the original machined-surface implants. Such findings are significant because various implant designs may allow the fixtures to sufficiently resist functional loading sooner than originally thought. The case report presented here indicates that immediate loading of hexed titanium screw-type implants in the anterior mandible can lead to successful osseointegration and clinical outcome. The number of implants placed, their distribution, and the type of rigid connection are critical considerations for immediate loading. A bone height that can accommodate dental implants > or = 10 mm long is recommended. Biomechanically, the implants to be immediately loaded must be stable and resistant to macromovement to ensure good osseointegration.

  5. In-vivo orthopedic implant diagnostic device for sensing load, wear, and infection

    DOEpatents

    Evans, III, Boyd McCutchen; Thundat, Thomas G.; Komistek, Richard D.; Dennis, Douglas A.; Mahfouz, Mohamed

    2006-08-29

    A device for providing in vivo diagnostics of loads, wear, and infection in orthopedic implants having at least one load sensor associated with the implant, at least one temperature sensor associated with the implant, at least one vibration sensor associated with the implant, and at least one signal processing device operatively coupled with the sensors. The signal processing device is operable to receive the output signal from the sensors and transmit a signal corresponding with the output signal.

  6. Early diagnosis of orthopedic implant failure using macromolecular imaging agents.

    PubMed

    Ren, Ke; Dusad, Anand; Zhang, Yijia; Purdue, P Edward; Fehringer, Edward V; Garvin, Kevin L; Goldring, Steven R; Wang, Dong

    2014-08-01

    To develop and evaluate diagnostic tools for early detection of wear particle-induced orthopaedic implant loosening. N-(2-Hydroxypropyl)methacrylamide (HPMA) copolymer was tagged with a near infrared dye and used to detect the inflammation induced by polymethylmethacrylate (PMMA) particles in a murine peri-implant osteolysis model. It was established by inserting an implant into the distal femur and challenging with routine PMMA particles infusion. The osteolysis was evaluated by micro-CT and histological analysis at different time points. Significant peri-implant osteolysis was found 3-month post PMMA particle challenge by micro-CT and histological analysis. At 1-month post challenge, when there was no significant peri-implant bone loss, the HPMA copolymer-near infrared dye conjugate was found to specifically target the femur with PMMA particles deposition, but not the contralateral control femur with phosphate buffered saline (PBS) infusion. The results from this study demonstrate the feasibility of utilizing the macromolecular diagnostic agent to detect particle-induced peri-implant inflammation prior to the development of detectable osteolysis. Recognition of this early pathological event would provide the window of opportunity for prevention of peri-implant osteolysis and subsequent orthopaedic implant failure.

  7. A glass fiber-reinforced composite - bioactive glass cranioplasty implant: A case study of an early development stage implant removed due to a late infection.

    PubMed

    Posti, Jussi P; Piitulainen, Jaakko M; Hupa, Leena; Fagerlund, Susanne; Frantzén, Janek; Aitasalo, Kalle M J; Vuorinen, Ville; Serlo, Willy; Syrjänen, Stina; Vallittu, Pekka K

    2015-03-01

    This case study describes the properties of an early development stage bioactive glass containing fiber-reinforced composite calvarial implant with histology that has been in function for two years and three months. The patient is a 33-year old woman with a history of substance abuse, who sustained a severe traumatic brain injury later unsuccessfully treated with an autologous bone flap and a custom-made porous polyethylene implant. She was thereafter treated with developmental stage glass fiber-reinforced composite - bioactive glass implant. After two years and three months, the implant was removed due to an implant site infection. The implant was analyzed histologically, mechanically, and in terms of chemistry and dissolution of bioactive glass. Mechanical integrity of the load bearing fiber-reinforced composite part of the implant was not affected by the in vivo period. Bioactive glass particles demonstrated surface layers of hydroxyapatite like mineral and dissolution, and related increase of pH was considerably less after two and three months period than that for fresh bioactive glass. There was a difference in the histology of the tissues inside the implant areas near to the margin of the implant that absorbed blood during implant installation surgery, showed fibrous tissue with blood vessels, osteoblasts, collagenous fibers with osteoid formation, and tiny clusters of more mature hard tissue. In the center of the implant, where there was less absorbed blood, only fibrous tissue was observed. This finding is in line with the combined positron emission tomography - computed tomography examination with (18F)-fluoride marker, which demonstrated activity of the mineralizing bone by osteoblasts especially at the area near to the margin of the implant 10 months after implantation. Based on these promising reactions found in the bioactive glass containing fiber-reinforced composite implant that has been implanted for two years and three months, calvarial

  8. Load fatigue performance of four implant-abutment interface designs: effect of torque level and implant system.

    PubMed

    Quek, H C; Tan, Keson B; Nicholls, Jack I

    2008-01-01

    Biomechanical load-fatigue performance data on single-tooth implant systems with different implant-abutment interface designs is lacking in the literature. This study evaluated the load fatigue performance of 4 implant-abutment interface designs (Brånemark-CeraOne; 3i Osseotite-STA abutment; Replace Select-Easy abutment; and Lifecore Stage-1-COC abutment system). The number of load cycles to fatigue failure of 4 implant-abutment designs was tested with a custom rotational load fatigue machine. The effect of increasing and decreasing the tightening torque by 20% respectively on the load fatigue performance was also investigated. Three different tightening torque levels (recommended torque, -20% recommended torque, +20% recommended torque) were applied to the 4 implant systems. There were 12 test groups with 5 samples in each group. The rotational load fatigue machine subjected specimens to a sinusoidally applied 35 Ncm bending moment at a test frequency of 14 Hz. The number of cycles to failure was recorded. A cutoff of 5 x 10(6) cycles was applied as an upper limit. There were 2 implant failures and 1 abutment screw failure in the Brånemark group. Five abutment screw failures and 4 implant failures was recorded for the 3i system. The Replace Select system had 1 implant failure. Five cone screw failures were noted for the Lifecore system. Analysis of variance revealed no statistically significant difference in load cycles to failure for the 4 different implant-abutment systems torqued at recommended torque level. A statistically significant difference was found between the -20% torque group and the +20% torque group (P < .05) for the 3i system. Load fatigue performance and failure location is system specific and related to the design characteristics of the implant-abutment combination. It appeared that if the implant-abutment interface was maintained, load fatigue failure would occur at the weakest point of the implant. It is important to use the torque level

  9. The effect of implant macro-thread design on implant stability in the early post-operative period: a randomized, controlled pilot study.

    PubMed

    McCullough, Jeffrey J; Klokkevold, Perry R

    2017-10-01

    of this study, macro-thread design appears to play a role in implant stability in the early post-operative healing period as assessed by RFA. These findings may have important implications related to immediate or early loading protocols. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  10. Random spectrum loading of dental implants: An alternative approach to functional performance assessment.

    PubMed

    Shemtov-Yona, K; Rittel, D

    2016-09-01

    The fatigue performance of dental implants is usually assessed on the basis of cyclic S/N curves. This neither provides information on the anticipated service performance of the implant, nor does it allow for detailed comparisons between implants unless a thorough statistical analysis is performed, of the kind not currently required by certification standards. The notion of endurance limit is deemed to be of limited applicability, given unavoidable stress concentrations and random load excursions, that all characterize dental implants and their service conditions. We propose a completely different approach, based on random spectrum loading, as long used in aeronautical design. The implant is randomly loaded by a sequence of loads encompassing all load levels it would endure during its service life. This approach provides a quantitative and comparable estimate of its performance in terms of lifetime, based on the very fact that the implant will fracture sooner or later, instead of defining a fatigue endurance limit of limited practical application. Five commercial monolithic Ti-6Al-4V implants were tested under cyclic, and another 5 under spectrum loading conditions, at room temperature and dry air. The failure modes and fracture planes were identical for all implants. The approach is discussed, including its potential applications, for systematic, straightforward and reliable comparisons of various implant designs and environments, without the need for cumbersome statistical analyses. It is believed that spectrum loading can be considered for the generation of new standardization procedures and design applications. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. An instrumented implant for vertebral body replacement that measures loads in the anterior spinal column.

    PubMed

    Rohlmann, Antonius; Gabel, Udo; Graichen, Friedmar; Bender, Alwina; Bergmann, Georg

    2007-06-01

    Realistic loads on a spinal implant are required among others for optimization of implant design and preclinical testing. In addition, such data may help to choose the optimal physiotherapy program for patients with such an implant and to evaluate the efficacy of aids like braces or crutches. Presently, no implant is available that can measure loads in the anterior spinal column during activities of daily life. Therefore, an implant instrumented for in vivo load measurement was developed for vertebral body replacement. The aim of this paper is to describe in detail a telemeterized implant that measures forces and moments acting on it. Six load sensors, a nine-channel telemetry unit and a coil for inductive power supply of the electronic circuits were integrated into a modified vertebral body replacement (Synex). The instrumented part of the implant is hermetically sealed. Patients are videotaped during measurements, and implant loads are displayed on and off line. The average accuracy of load measurement is better than 2% for force and 5% for moment components with reference to the maximum value of 3000 N and 20 Nm, respectively. The measuring implant described here will provide additional information on spinal loads.

  12. Displacement of dental implants in trabecular bone under a static lateral load in fresh bovine bone.

    PubMed

    Engelke, Wilfried; Müller, Alois; Decco, Oscar A; Rau, María J; Cura, Andrea C; Ruscio, Mara L; Knösel, Michael

    2013-04-01

    The study aims to provide objective data for the displacement of titanium screw implants in trabecular bone specimens. One hundred Semados implants (Bego, Bremen, Germany) were inserted in bovine type IV bone specimens. All implants had a diameter of 3.75 mm; 50 implants had a length of 8.5 mm and 50 implants had a length of 15 mm. Insertion torque was determined at intervals of 10, 20, and 30 Ncm. Implants were loaded horizontally with 10, 20, and 30 N for 2 seconds. An indicator strip was attached to the implant abutment to allow direct observation of implant movement relative to the bone surface. Horizontal displacement was assessed with an accuracy of measurement of 10 µm. Seven implants got lost by visible loosening. Degree of displacement was subject to evaluation with all others. Those implants showed a mean displacement of 59 µm for 10 N (n = 100), 173 µm for 20 N (n = 99), and 211 µm for 30 N (n = 93). The mean displacement of 15-mm implants (16, 37, 51 µm) was significantly lower compared with 8.5-mm implants (103, 311, 396 µm) corresponding to 10, 20, and 30 N as lateral loads. Displacement of screw implants in trabecular bone can be detected and visualized using commercially available endoscopes with a high magnification. A lateral load of 20 N indicates a mean displacement of over 100 µm and therefore results in a critical displacement. © 2011 Wiley Periodicals, Inc.

  13. Immediately loaded mini dental implants as overdenture retainers: 1-Year cohort study of implant stability and peri-implant marginal bone level.

    PubMed

    Šćepanović, Miodrag; Todorović, Aleksandar; Marković, Aleksa; Patrnogić, Vesna; Miličić, Biljana; Moufti, Adel M; Mišić, Tijana

    2015-05-01

    This 1-year cohort study investigated stability and peri-implant marginal bone level of immediately loaded mini dental implants used to retain overdentures. Each of 30 edentulous patients received 4 mini dental implants (1.8 mm × 13 mm) in the interforaminal mandibular region. The implants were immediately loaded with pre-made overdentures. Outcome measures included implant stability and bone resorption. Implant stability was measured using the Periotest Classic(®) device immediately after placement and on the 3rd and 6th weeks and the 4th, 6th and 12th months postoperatively. The peri-implant marginal bone level (PIBL) was evaluated at the implant's mesial and distal sides from the polished platform to the marginal crest. Radiographs were taken using a tailored film holder to reproducibly position the X-ray tube at the 6th week, 4th and 12th months postoperatively. The primary stability (Periotest value, PTV) measured -0.27 ± 3.41 on a scale of -8 to + 50 (lower PTV reflects higher stability). The secondary stability decreased significantly until week 6 (mean PTV = 7.61 ± 7.05) then increased significantly reaching (PTV = 6.17 ± 6.15) at 12 months. The mean PIBL measured -0.40 mm after 1 year of functional loading, with no statistically significant differences at the various follow-ups (p = 0.218). Mini dental implants placed into the interforaminal region could achieve a favorable primary stability for immediate loading. The follow-up Periotest values fluctuated, apparently reflecting the dynamics of bone remodeling, with the implants remaining clinically stable (98.3%) after 1 year of function. The 1-year bone resorption around immediately loaded MDIs is within the clinically acceptable range for standard implants. Copyright © 2014 Elsevier GmbH. All rights reserved.

  14. Time Course of Peri-Implant Bone Regeneration around Loaded and Unloaded Implants in a Rat Model

    PubMed Central

    Jariwala, Shailly H.; Wee, Hwabok; Roush, Evan P.; Whitcomb, Tiffany L.; Murter, Christopher; Kozlansky, Gery; Lakhtakia, Akhlesh; Kunselman, Allen R.; Donahue, Henry J.; Armstrong, April D.; Lewis, Gregory S.

    2018-01-01

    The time-course of cancellous bone regeneration surrounding mechanically loaded implants affects implant fixation, and is relevant to determining optimal rehabilitation protocols following orthopaedic surgeries. We investigated the influence of controlled mechanical loading of titanium-coated polyether-ether ketone (PEEK) implants on osseointegration using time-lapsed, non-invasive, in vivo micro-computed tomography (micro-CT) scans. Implants were inserted into proximal tibial metaphyses of both limbs of eight female Sprague-Dawley rats. External cyclic loading (60 μm or 100 μm displacement, 1 Hz, 60 seconds) was applied every other day for 14 days to one implant in each rat, while implants in contralateral limbs served as the unloaded controls. Hind limbs were imaged with high-resolution micro-CT (12.5 μm voxel size) at 2, 5, 9, and 12 days post-surgery. Trabecular changes over time were detected by 3D image registration allowing for measurements of bone-formation rate (BFR) and bone-resorption rate (BRR). At day 9, mean %BV/TV for loaded and unloaded limbs were 35.5 ± 10.0 % and 37.2 ± 10.0 %, respectively, and demonstrated significant increases in bone volume compared to day 2. BRR increased significantly after day 9. No significant differences between bone volumes, BFR, and BRR were detected due to implant loading. Although not reaching significance (p = 0.16), an average 119 % increase in pull-out strength was measured in the loaded implants. PMID:27381807

  15. Does aquatic exercise reduce hip and knee joint loading? In vivo load measurements with instrumented implants

    PubMed Central

    Kutzner, Ines; Dymke, Jörn; Damm, Philipp; Duda, Georg N.; Günzl, Reiner; Bergmann, Georg

    2017-01-01

    Aquatic exercises are widely used for rehabilitation or preventive therapies in order to enable mobilization and muscle strengthening while minimizing joint loading of the lower limb. The load reducing effect of water due to buoyancy is a main advantage compared to exercises on land. However, also drag forces have to be considered that act opposite to the relative motion of the body segments and require higher muscle activity. Due to these opposing effects on joint loading, the load-reducing effect during aquatic exercises remains unknown. The aim of this study was to quantify the joint loads during various aquatic exercises and to determine the load reducing effect of water. Instrumented knee and hip implants with telemetric data transfer were used to measure the resultant joint contact forces in 12 elderly subjects (6x hip, 6x knee) in vivo. Different dynamic, weight-bearing and non-weight-bearing activities were performed by the subjects on land and in chest-high water. Non-weight-bearing hip and knee flexion/extension was performed at different velocities and with additional Aquafins. Joint forces during aquatic exercises ranged between 32 and 396% body weight (BW). Highest forces occurred during dynamic activities, followed by weight-bearing and slow non-weight-bearing activities. Compared to the same activities on land, joint forces were reduced by 36–55% in water with absolute reductions being greater than 100%BW during weight-bearing and dynamic activities. During non-weight-bearing activities, high movement velocities and additional Aquafins increased the joint forces by up to 59% and resulted in joint forces of up to 301%BW. This study confirms the load reducing effect of water during weight-bearing and dynamic exercises. Nevertheless, high drag forces result in increased joint contact forces and indicate greater muscle activity. By the choice of activity, movement velocity and additional resistive devices joint forces can be modulated individually in

  16. Does aquatic exercise reduce hip and knee joint loading? In vivo load measurements with instrumented implants.

    PubMed

    Kutzner, Ines; Richter, Anja; Gordt, Katharina; Dymke, Jörn; Damm, Philipp; Duda, Georg N; Günzl, Reiner; Bergmann, Georg

    2017-01-01

    Aquatic exercises are widely used for rehabilitation or preventive therapies in order to enable mobilization and muscle strengthening while minimizing joint loading of the lower limb. The load reducing effect of water due to buoyancy is a main advantage compared to exercises on land. However, also drag forces have to be considered that act opposite to the relative motion of the body segments and require higher muscle activity. Due to these opposing effects on joint loading, the load-reducing effect during aquatic exercises remains unknown. The aim of this study was to quantify the joint loads during various aquatic exercises and to determine the load reducing effect of water. Instrumented knee and hip implants with telemetric data transfer were used to measure the resultant joint contact forces in 12 elderly subjects (6x hip, 6x knee) in vivo. Different dynamic, weight-bearing and non-weight-bearing activities were performed by the subjects on land and in chest-high water. Non-weight-bearing hip and knee flexion/extension was performed at different velocities and with additional Aquafins. Joint forces during aquatic exercises ranged between 32 and 396% body weight (BW). Highest forces occurred during dynamic activities, followed by weight-bearing and slow non-weight-bearing activities. Compared to the same activities on land, joint forces were reduced by 36-55% in water with absolute reductions being greater than 100%BW during weight-bearing and dynamic activities. During non-weight-bearing activities, high movement velocities and additional Aquafins increased the joint forces by up to 59% and resulted in joint forces of up to 301%BW. This study confirms the load reducing effect of water during weight-bearing and dynamic exercises. Nevertheless, high drag forces result in increased joint contact forces and indicate greater muscle activity. By the choice of activity, movement velocity and additional resistive devices joint forces can be modulated individually in the

  17. Immediate versus conventional loading of implant-supported maxillary overdentures: a finite element stress analysis.

    PubMed

    Akca, Kivanc; Eser, Atilim; Eckert, Steven; Cavusoglu, Yeliz; Cehreli, Murat Cavit

    2013-01-01

    To compare biomechanical outcomes of immediately and conventionally loaded bar-retained implant-supported maxillary overdentures using finite element stress analysis. Finite element models were created to replicate the spatial positioning of four 4.1 × 12-mm implants in the completely edentulous maxillae of four cadavers to support bar-retained overdentures with 7-mm distal extension cantilevers. To simulate the bone-implant interface of immediately loaded implants, a contact situation was defined at the interface; conventional loading was simulated by "bonding" the implants to the surrounding bone. The prostheses were loaded with 100 N in the projected molar regions bilaterally, and strain magnitudes were measured at the buccal aspect of bone. The amplitude of axial and lateral strains, the overall strain magnitudes, and the strain magnitudes around anterior and posterior implants in the immediate loading group were comparable to those seen in the conventional loading group, suggesting that the loading regimens created similar stress/strain fields (P > .05). Conventional and immediate loading of maxillary implants supporting bar-retained overdentures resulted in similar bone strains.

  18. Advanced immediate functional loading: requirements for long-term success in modern implant dentistry.

    PubMed

    Romanos, Georgios E

    2014-01-01

    There are benefits to be derived from the use of advanced surgical protocols in conjunction with immediate functional loading using various dental implant designs and implant-abutment connections. Clinical protocols with simultaneous bone grafting, immediate implant placement, and/or sinus augmentations when a shortened treatment period is needed are included in this report, with the aim of providing understanding of the main protocol characteristics and prerequisites for long-term success in implant dentistry. This article presents three clinical cases that illustrate possibilities for advanced immediate loading using different implant designs. It demonstrates treatment of severe bone defects and the facilitation of placing implants in regenerated bone that can be immediately loaded.

  19. Instant loading with intraoral welding technique and PRAMA implants: a new prosthetic approach.

    PubMed

    Celletti, R; Fanali, S; Laici, C U; Santori, C; Pignatelli, P; Sinjari, B

    2017-01-01

    When splinting multiple implants passive fit of the framework should be achieved to avoid excessive force distribution on the implants. Recently, a protocol was suggested for immediate loading of multiple implants by welding a titanium bar to implant abutments directly in the oral cavity so as to create a customized, precise and passive metal-reinforced provisional restoration. The intraoral welding technique subsequently proves to be a successful option in the full-arch immediate restorations of the mandible and maxilla. The aim of this article is to present a case report in which a new prosthetic approach, using trans-mucosal implants, is described. Dental implants are instantly loaded with a provisional prosthesis supported by an intraoral welded titanium framework to obtain a precise passive fit of the immediate loaded prosthesis.

  20. Characteristics of early versus late implant failure: a retrospective study.

    PubMed

    Manor, Yifat; Oubaid, Saheer; Mardinger, Ofer; Chaushu, Gavriel; Nissan, Joseph

    2009-12-01

    Implant failures can be divided into early and late according to the timing of failure. The purpose of this study was to characterize and compare both types. A retrospective cohort study was conducted in 194 patients (98 men and 96 women) who presented after dental implant failures during a 6-year period (2000 to 2006). The patient served as the unit of analysis. A history of at least 1 failed and removed dental implant served as the inclusion criterion. Patients were excluded from this study whenever their files had missing data. The collected data included a patient's characteristics, failure characteristics, and the anatomic status of the alveolar ridge after failure. Late failures were associated with moderate to severe bone loss, a larger number of failed implants per patient, a higher incidence in men, and mostly in posterior areas. Early failures were associated with minimal bone loss, occurred more in women, at a younger age, and in most cases the implants were intended to support single crowns. Meticulous follow-up is needed to reveal and treat failing or ailing implants. Once established as hopeless, they should be removed as soon as possible to prevent further bone loss.

  1. Biomechanical optimization of implant diameter and length for immediate loading: a nonlinear finite element analysis.

    PubMed

    Kong, Liang; Gu, Zexu; Li, Tao; Wu, Junjie; Hu, Kaijin; Liu, Yanpu; Zhou, Hongzhi; Liu, Baolin

    2009-01-01

    A nonlinear finite element method was applied to examine the effects of implant diameter and length on the maximum von Mises stresses in the jaw, and to evaluate the maximum displacement of the implant-abutment complex in immediate-loading models. The implant diameter (D) ranged from 3.0 to 5.0 mm and implant length (L) ranged from 6.0 to 16.0 mm. The results showed that the maximum von Mises stress in cortical bone was decreased by 65.8% under a buccolingual load with an increase in D. In cancellous bone, it was decreased by 71.5% under an axial load with an increase in L. The maximum displacement in the implant-abutment complex decreased by 64.8% under a buccolingual load with an increase in D. The implant was found to be more sensitive to L than to D under axial loads, while D played a more important role in enhancing its stability under buccolingual loads. When D exceeded 4.0 mm and L exceeded 11.0 mm, both minimum stress and displacement were obtained. Therefore, these dimensions were the optimal biomechanical selections for immediate-loading implants in type B/2 bone.

  2. Satisfaction and Clinical Outcomes Among Patients with Immediately Loaded Mandibular Overdentures Supported by One or Two Dental Implants: Results of a 5-Year Prospective Randomized Clinical Trial.

    PubMed

    Kronstrom, Mats; Davis, Ben; Loney, Robert; Gerrow, Jack; Hollender, Lars

    The purpose of this study was to evaluate patient satisfaction and clinical outcomes among subjects with mandibular overdentures supported by one or two immediately placed dental implants 5 years after loading. Thirty-six subjects (16 men and 20 women) received one or two dental implants in the anterior mandible, and all implants were loaded the day of surgery. Subjects were scheduled for follow-up 3-, 6-, and 12 months after implant placement and thereafter annually for 4 more years. Patient satisfaction scores were measured with the Oral Health Impact Profile-EDENT (OHIPEDENT) questionnaire. Seventeen subjects (7 male and 10 female) with a mean age of 59.4 years (range, 44 to 74 years) were available for the 5-year follow-up examination. Nine subjects with 10 failing implants were excluded during the first year and nine subjects were lost to follow-up. No implants failed between the 12- and 60-month follow-up examinations, and the need for denture maintenance was low. Mean peri-implant bone change was 0.92 mm, and the Spearman test failed to show correlation between the insertion torque value and implant stability quotient. Patient satisfaction scores increased significantly when compared with baseline values and continued to be high for both groups, with no significant differences. Ten implants in nine subjects failed early, but no failures were observed after the 12-month examination. No significant differences were found between subjects in the two groups with respect to implant survival rates and peri-implant bone loss, and patient satisfaction scores continued to be high. Although patient satisfaction and implant success were high during the 12- to 60-month period, the results should be interpreted with caution because of the high number of failing implants and patients lost to follow-up. More research is needed to study outcomes of treatment with immediately loaded mandibular implant overdentures.

  3. Properties of axially loaded implant-abutment assemblies using digital holographic interferometry analysis.

    PubMed

    Brozović, Juraj; Demoli, Nazif; Farkaš, Nina; Sušić, Mato; Alar, Zeljko; Gabrić Pandurić, Dragana

    2014-03-01

    The aim of this study was to (i) obtain the force-related interferometric patterns of loaded dental implant-abutment assemblies differing in diameter and brand using digital holographic interferometry (DHI) and (ii) determine the influence of implant diameter on the extent of load-induced implant deformation by quantifying and comparing the obtained interferometric data. Experiments included five implant brands (Ankylos, Astra Tech, blueSKY, MIS and Straumann), each represented by a narrow and a wide diameter implant connected to a corresponding abutment. A quasi-Fourier setup with a 25mW helium-neon laser was used for interferometric measurements in the cervical 5mm of the implants. Holograms were recorded in two conditions per measurement: a 10N preloaded and a measuring-force loaded assembly, resulting with an interferogram. This procedure was repeated throughout the whole process of incremental axial loading, from 20N to 120N. Each measurement series was repeated three times for each assembly, with complete dismantling of the implant-loading device in between. Additional software analyses calculated deformation data. Deformations were presented as mean values±standard deviations. Statistical analysis was performed using linear mixed effects modeling in R's lme4 package. Implants exhibited linear deformation patterns. The wide diameter group had lower mean deformation values than the narrow diameter group. The diameter significantly affected the deformation throughout loading sessions. This study gained in vitro implant performance data, compared the deformations in implant bodies and numerically stated the biomechanical benefits of wider diameter implants. Copyright © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  4. Micro finite element analysis of dental implants under different loading conditions.

    PubMed

    Marcián, Petr; Wolff, Jan; Horáčková, Ladislava; Kaiser, Jozef; Zikmund, Tomáš; Borák, Libor

    2018-05-01

    Osseointegration is paramount for the longevity of dental implants and is significantly influenced by biomechanical stimuli. The aim of the present study was to assess the micro-strain and displacement induced by loaded dental implants at different stages of osseointegration using finite element analysis (FEA). Computational models of two mandible segments with different trabecular densities were constructed using microCT data. Three different implant loading directions and two osseointegration stages were considered in the stress-strain analysis of the bone-implant assembly. The bony segments were analyzed using two approaches. The first approach was based on Mechanostat strain intervals and the second approach was based on tensile/compression yield strains. The results of this study revealed that bone surrounding dental implants is critically strained in cases when only a partial osseointegration is present and when an implant is loaded by buccolingual forces. In such cases, implants also encounter high stresses. Displacements of partially-osseointegrated implant are significantly larger than those of fully-osseointegrated implants. It can be concluded that the partial osseointegration is a potential risk in terms of implant longevity. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Clinical evaluation of a novel dental implant system as single implants under immediate loading conditions - 4-month post-loading results from a multicentre randomised controlled trial.

    PubMed

    Esposito, Marco; Trullenque-Eriksson, Anna; Blasone, Rodolfo; Malaguti, Giuliano; Gaffuri, Cristiano; Caneva, Marco; Minciarelli, Armando; Luongo, Giuseppe

    To evaluate the safety and clinical effectiveness of a novel dental implant system (GENESIS Implant System, Keystone Dental, Massachusetts, USA) using another dental implant system by the same manufacturer as a control (PRIMA Implant System, Keystone Dental). A total of 53 patients requiring at least two single crowns had their sites randomised according to a split-mouth design to receive both implant systems at six centres. If implants could be placed with a torque superior to 40 Ncm they were to be loaded immediately with provisional crowns, otherwise after 3 months of submerged healing. Provisional crowns were replaced by definitive crowns 4 months after initial loading, when the follow-up period for the initial part of this study was completed. Outcome measures were crown/implant failures, complications, pink esthetic score (PES), peri-implant marginal bone level changes, plaque score, marginal bleeding, patients and preference of the clinician. In total 53 PRIMA and 53 GENESIS implants were placed. Three patients dropped out but all of the remaining patients were followed up to 4-months post-loading. No PRIMA implant failed whereas four GENESIS implants failed. Only two complications were reported for PRIMA implants. There were no statistically significant differences for crown/implant failures (difference in proportions = 0.080; P (McNemar test) = 0.125) and complications (difference in proportions = -0.04; P (McNemar test) = 0.500) between the implant systems. There were no differences at 4-months post-loading for plaque (difference = -0.54, 95% CI: -3.01 to 1.93; P (Paired t-test) = 0.660), marginal bleeding (difference = -3.8, 95% CI: -7.63 to 0.019; P (Paired t-test) = 0.051), PES (difference = 0.47, 95% CI: -0.56 to 1.50; P (Paired t-test) = 0.365) and marginal bone level changes (difference in mm = -0.04, 95% CI: -0.33 to 0.26; P (Paired t-test) = 0.795). The majority of the patients (46) had no

  6. Influence of abutment design on the success of immediately loaded dental implants: experimental and numerical studies.

    PubMed

    Hasan, I; Röger, B; Heinemann, F; Keilig, L; Bourauel, C

    2012-09-01

    The aim of the present study was to investigate experimentally and numerically the influence of a fine threaded- against a roughened-cervical region of immediately loaded dental implants in combination with straight and 20°-angled abutments on the implant primary stability. A total of 30 implants were inserted in bovine rib-segments, 14 cervically roughened implants and 16 implants with fine cervical threads. Each implant system received two abutments, straight and 20°-angled. Implant displacements and rotations were measured using a biomechanical measurement system. Subsequently, eight samples were selected for geometrical reconstruction and numerical investigation of stress and strain distributions in the bone by means of the finite element method. Experimentally, both implant systems showed similar behaviour with the straight abutments concerning displacements and rotations. However, fine threaded implants showed much less displacement and rotation against roughened implants when angled abutments were considered. Numerically, stresses were within 35-45 MPa in the cortical bone for both implant systems. The strains showed highest values within the spongious bone with the roughened implants connected to angled abutments. The results indicate that implants with fine cervical threads could be recommended in particular with angled abutments. The outcomes of this study are currently confirmed by long-term clinical investigations. Copyright © 2011 IPEM. Published by Elsevier Ltd. All rights reserved.

  7. Success and High Predictability of Intraorally Welded Titanium Bar in the Immediate Loading Implants

    PubMed Central

    Fogli, Vaniel; Camerini, Michele; Carinci, Francesco

    2014-01-01

    The implants failure may be caused by micromotion and stress exerted on implants during the phase of bone healing. This concept is especially true in case of implants placed in atrophic ridges. So the primary stabilization and fixation of implants are an important goal that can also allow immediate loading and oral rehabilitation on the same day of surgery. This goal may be achieved thanks to the technique of welding titanium bars on implant abutments. In fact, the procedure can be performed directly in the mouth eliminating possibility of errors or distortions due to impression. This paper describes a case report and the most recent data about long-term success and high predictability of intraorally welded titanium bar in immediate loading implants. PMID:24963419

  8. Esthetic Outcomes of Immediately Loaded Locking Taper Implants in the Anterior Maxilla: A Case Series Study.

    PubMed

    Lombardo, Giorgio; Corrocher, Giovanni; Pighi, Jacopo; Mascellaro, Anna; Marincola, Mauro; Nocini, Per Francesco

    2016-06-01

    The purpose of this study was to evaluate the esthetic outcome of single-tooth locking taper connection implants placed in the anterior maxilla following a postextractive nonfunctional loading protocol. This preliminary clinical study involving 16 patients evaluated the results of 21 implants placed in areas with high esthetic value. For each implant the pink esthetic score, white esthetic score, cumulative survival rate, and health status of peri-implant tissues were evaluated. The cumulative survival rate was 100% 2 years after prosthetic loading, and the mean total pink esthetic score/white esthetic score was 16.9 ± 1.14 on a maximum value of 20. There was excellent plaque control in all patients, and inflammation indices were within the norm. Within the limits of this study, this immediate nonfunctional loading protocol seems to be a successful procedure esthetically and for the maintenance of peri-implant soft tissues.

  9. Effect of radial head implant shape on joint contact area and location during static loading.

    PubMed

    Shannon, Hannah L; Deluce, Simon R; Lalone, Emily A; Willing, Ryan; King, Graham J W; Johnson, James A

    2015-04-01

    To examine the effect of implant shape on radiocapitellar joint contact area and location in vitro. We used 8 fresh-frozen cadaveric upper extremities. An elbow loading simulator examined joint contact in pronation, neutral rotation, and supination with the elbow at 90° flexion. Muscle tendons were attached to pneumatic actuators to allow for computer-controlled loading to achieve the desired forearm rotation. We performed testing with the native radial head, an axisymmetric implant, a reverse-engineered patient-specific implant, and a population-based quasi-anatomic implant. Implants were inserted using computer navigation. Contact area and location were quantified using a casting technique. We found no significant difference between contact locations for the native radial head and the 3 implants. All of the implants had a contact area lower than the native radial head; however, only the axisymmetric implant was significantly different. There was no significant difference in contact area between implant shapes. The similar contact areas and locations of the 3 implant designs suggest that the shape of the implant may not be important with respect to radiocapitellar joint contact mechanics when placed optimally using computer navigation. Further work is needed to explore the sensitivity of radial head implant malpositioning on articular contact. The lower contact area of the radial head implants relative to the native radial head is similar to previous benchtop studies and is likely the result of the greater stiffness of the implant. Radial head implant shape does not appear to have a pronounced influence on articular contact, and both axisymmetric and anatomic metal designs result in elevated cartilage stress relative to the intact state. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  10. Immediate vs non-immediate loading post-extractive implants: a comparative study of implant stability quotient (ISQ)

    PubMed Central

    MILILLO, L.; FIANDACA, C.; GIANNOULIS, F.; OTTRIA, L.; LUCCHESE, A.; SILVESTRE, F.; PETRUZZI, M.

    2016-01-01

    SUMMARY Purpose This study aims to evaluate differences in implant stability between post-extractive implants vs immediately placed post-extractive implants by resonance frequency analysis (RFA). Materials and methods Patients were grouped into two different categories. In Group A 10 patients had an immediate post-extractive implant, then a provisional, acrylic resin crown was placed (immediate loading). In Group B (control group) 10 patients only had an immediate post-extractive implant. Both upper and lower premolars were chosen as post-extractive sites. Implant Stability Quotient (ISQ) was measured thanks to RFA measurements (Osstell®). Five intervals were considered: immediately after surgery (T0) and every four weeks, until five months after implant placement (T1, T2, T3, T4,T5). A statistical analysis by means of Student’s T-test (significance set at p<0.05) for independent sample was carried out in order to compare Groups A and B. Results The ISQ value between the two groups showed a statistically significant difference (p<0.02) at T1. No statistically significant difference in ISQ was assessed at T0, T2, T3, T4 and T5. Conclusions After clinical assessment it is possible to confirm that provisional and immediate prosthetic surgery in post-extraction sites with cone-shaped implants, platform-switching abutment and bioactive surface can facilitate osseointegration, reducing healing time. PMID:28042440

  11. Effect of implant number and distribution on load transfer in implant-supported partial fixed dental prostheses for the anterior maxilla: A photoelastic stress analysis study.

    PubMed

    Lee, Jae-In; Lee, Yoon; Kim, Yu-Lee; Cho, Hye-Won

    2016-02-01

    The 4-, 3- or even 2-implant-supported partial fixed dental prosthesis (PFDP) designs have been used to rehabilitate the anterior edentulous maxilla. The purpose of this in vitro study was to compare the stress distribution in the supporting tissues surrounding implants placed in the anterior maxilla with 5 PFDP designs. A photoelastic model of the human maxilla with an anterior edentulous region was made with photoelastic resin (PL-2; Vishay Micro-Measurements), and 6 straight implants (OsseoSpeed; Astra Tech AB) were placed in the 6 anterior tooth positions. The 5 design concepts based on implant location were as follows: model 6I: 6 implants; model 2C2CI: 4 implants (2 canines and 2 central incisors); model 2C2LI: 4 implants (2 canines and 2 lateral incisors); model 2C1CI: 3 implants (2 canines and 1 central incisor); and model 2C: 2 canines. A load of 127.4 N was applied on the cingulum of 3 teeth at a 30-degree angle to the long axis of the implant. Stresses that developed in the supporting structure were recorded photographically. The 6-implant-supported PFDP exhibited the most even and lowest distribution of stresses in all loading conditions. When the canine was loaded, the 2- or 3-implant-supported PFDP showed higher stresses around the implant at the canine position than did the 4- or 6-implant-supported PFDP. When the central incisor or lateral incisor was loaded, the two 4-implant-supported PFDPs exhibited similar levels of stresses around the implants and showed lower stresses than did the 2- or 3-implant-supported PFDP. Implant number and distribution influenced stress distribution around the implants in the anterior maxilla. With a decrease in implant number, the stresses around the implants increased. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  12. Immediate Loading of Tapered Implants Placed in Postextraction Sockets and Healed Sites.

    PubMed

    Han, Chang-Hun; Mangano, Francesco; Mortellaro, Carmen; Park, Kwang-Bum

    2016-07-01

    The aim of the present study was to compare the survival, stability, and complications of immediately loaded implants placed in postextraction sockets and healed sites. Over a 2-year period, all patients presenting with partial or complete edentulism of the maxilla and/or mandible (healed site group, at least 4 months of healing after tooth extraction) or in need of replacement of nonrecoverable failing teeth (postextraction group) were considered for inclusion in this study. Tapered implants featuring a nanostructured calcium-incorporated surface were placed and loaded immediately. The prosthetic restorations comprised single crowns, fixed partial dentures, and fixed full arches. Primary outcomes were implant survival, stability, and complications. Implant stability was assessed at placement and at each follow-up evaluation (1 week, 3 months, and 1 year after placement): implants with an insertion torque (IT) <45 N·cm and/or with an implant stability quotient (ISQ) <70 were considered failed for immediate loading. A statistical analysis was performed. Thirty implants were placed in postextraction sockets of 17 patients, and 32 implants were placed in healed sites of 22 patients. There were no statistically significant differences in ISQ values between the 2 groups, at each assessment. In total, 60 implants (96.8%) had an IT ≥45 and an ISQ ≥70 at placement and at each follow-up control: all these implants were successfully loaded. Only 2 implants (1 in a postextraction socket and 1 in a healed site, 3.2%) could not achieve an IT ≥45 N·cm and/or an ISQ ≥70 at placement or over time: accordingly, these were considered failed for stability, as they could not be subjected to immediate loading. One of these 2 implants, in a healed site of a posterior maxilla, had to be removed, yielding an overall 1-year implant survival rate of 98.4%. No complications were reported. No significant differences were reported between the 2 groups with respect to implant

  13. Bone microstrain values of 1-piece and 2-piece implants subjected to mechanical loading.

    PubMed

    Harel, Noga; Eshkol-Yogev, Inbar; Piek, Dana; Livne, Shiri; Lavi, David; Ormianer, Zeev

    2013-06-01

    The purpose of this study was to measure and compare the strain levels in peri-implant bone as generated by 1-piece (1P) and 2-piece (2P) implant systems. The implants (1P and 2P) were placed into bovine bone according to the manufacturer's protocol. Four linear strain gauges were placed around each implant neck and apex. Each model was loaded in static loading by a material testing machine in ascending forces ranging from 20 to 120 N. Microstrains (μ[Latin Small Letter Open E]) generated in the surrounding bone were measured by a strain gauge and recorded. Recorded microstrains were significantly higher for 1P implants than for 2P implants. Average recorded microstrain values were significantly lower in the neck (71.6 and 17.3 µs) compared with the apical (132 and 60 µs) regions of 1P and 2P implants, respectively (P < 0.0001). Within the limitations of this study, highest microstrains were generated in apical regions regardless of implant design, but the 2P implant ap-peared to provide a stress-damping effect in both the cervical and apical regions compared with the 1P implant.

  14. Load Transfer Characteristics of Three-Implant-Retained Overdentures with Different Interimplant Distances.

    PubMed

    Tokar, Emre; Uludag, Bulent; Karacaer, Ozgul

    Implant-retained overdentures are the first choice of rehabilitation for edentulous mandibles. Bone morphology and anatomical landmarks may be influenced by the location and angulation of implants and distances between the implants. The purpose of this study was to investigate stress distribution characteristics and to compare stress levels of three different attachment designs of three-implant-retained mandibular overdentures with three different interimplant distances. Three photoelastic mandibular models with three implants were fabricated using an edentulous mandible cast with moderate residual ridge resorption. The center implants were embedded parallel to the midline, and the distal implants were aligned at a 20-degree angulation corresponding to the center implants. Distances between the center and distal implants were set at 11, 18, and 25 mm at the photoelastic models. Bar, bar-ball, and Locator attachment-retained overdentures were prepared for the models. Vertical loads were applied to the overdentures, and stress levels and distribution were evaluated by a circular polariscope. The greatest observed stress level was moderate for the tested overdenture designs. The Locator attachment system showed the lowest stress level for the 11-mm and 25-mm photoelastic models. The bar attachment design transmitted less stress compared with the other tested designs for the 18-mm photoelastic model. Stresses were observed on the loaded side of the photoelastic models. The lowest stress was found with the Locator and bar attachments for the 11-mm photoelastic model, which transmitted little or no discernible stress around the implants.

  15. Biomechanics and strain mapping in bone as related to immediately-loaded dental implants

    PubMed Central

    Du, Jing; Lee, Jihyun; Jang, Andrew; Gu, Allen; Hossaini-Zadeh, Mehran; Prevost, Richard; Curtis, Don; Ho, Sunita

    2015-01-01

    The effects of alveolar bone socket geometry and bone-implant contact on implant biomechanics, and resulting strain distributions in bone were investigated. Following extraction of lateral incisors on a cadaver mandible, immediate implants were placed and bone-implant contact area, stability and bone strain were measured. In situ biomechanical testing coupled with micro X-ray microscope (μ-XRM) illustrated less stiff bone-implant complexes (701-822 N/mm) compared with bone-periodontal ligament (PDL)-tooth complexes (791-913 N/mm). X-ray tomograms illustrated that the cause of reduced stiffness was due to reduced and limited bone-implant contact. Heterogeneous elemental composition of bone was identified by using energy dispersive X-ray spectroscopy (EDS). The novel aspect of this study was the application of a new experimental mechanics method, that is, digital volume correlation, which allowed mapping of strains in volumes of alveolar bone in contact with a loaded implant. The identified surface and subsurface strain concentrations were a manifestation of load transferred to bone through bone-implant contact based on bone-implant geometry, quality of bone, implant placement, and implant design. 3D strain mapping indicated that strain concentrations are not exclusive to the bone-implant contact regions, but also extend into bone not directly in contact with the implant. The implications of the observed strain concentrations are discussed in the context of mechanobiology. Although a plausible explanation of surgical complications for immediate implant treatment is provided, extrapolation of results is only warranted by future systematic studies on more cadaver specimens and/or in vivo small scale animal models. PMID:26162549

  16. Assessment of Embedded Conjugated Polymer Sensor Arrays for Potential Load Transmission Measurement in Orthopaedic Implants

    PubMed Central

    Micolini, Carolina; Holness, Frederick Benjamin; Johnson, James A.

    2017-01-01

    Load transfer through orthopaedic joint implants is poorly understood. The longer-term outcomes of these implants are just starting to be studied, making it imperative to monitor contact loads across the entire joint implant interface to elucidate the force transmission and distribution mechanisms exhibited by these implants in service. This study proposes and demonstrates the design, implementation, and characterization of a 3D-printed smart polymer sensor array using conductive polyaniline (PANI) structures embedded within a polymeric parent phase. The piezoresistive characteristics of PANI were investigated to characterize the sensing behaviour inherent to these embedded pressure sensor arrays, including the experimental determination of the stable response of PANI to continuous loading, stability throughout the course of loading and unloading cycles, and finally sensor repeatability and linearity in response to incremental loading cycles. This specially developed multi-material additive manufacturing process for PANI is shown be an attractive approach for the fabrication of implant components having embedded smart-polymer sensors, which could ultimately be employed for the measurement and analysis of joint loads in orthopaedic implants for in vitro testing. PMID:29186079

  17. Load Fatigue Performance Evaluation on Two Internal Tapered Abutment-Implant Connection Implants Under Different Screw Tightening Torques.

    PubMed

    Jeng, Ming-Dih; Liu, Po-Yi; Kuo, Jia-Hum; Lin, Chun-Li

    2017-04-01

    This study evaluates the load fatigue performance of different abutment-implant connection implant types-retaining-screw (RS) and taper integrated screwed-in (TIS) types under 3 applied torque levels based on the screw elastic limit. Three torque levels-the recommended torque (25 Ncm), 10% less, and 10% more than the ratio of recommended torque to screw elastic limits of different implants were applied to the implants to perform static and dynamic testing according to the ISO 14801 method. Removal torque loss was calculated for each group after the endurance limitation was reached (passed 5 × 10 6 cycles) in the fatigue test. The static fracture resistance results showed that the fracture resistance in the TIS-type implant significantly increased (P < .05) when the abutment screw was inserted tightly. The dynamic testing results showed that the endurance limitations for the RS-type implant were 229 N, 197 N, and 224 N and those for the TIS-type implant were 322 N, 364 N, and 376 N when the screw insertion torques were applied from low to high. The corresponding significant (P < .05) removal torque losses for the TIS-type implant were 13.2%, 5.3%, and 2.6% but no significant difference was found for the RS-type implant. This study concluded that the static fracture resistance and dynamic endurance limitation of the TIS-type implant (1-piece solid abutment) increased when torque was applied more tightly on the screw. Less torque loss was also found when increasing the screw insertion torque.

  18. In vivo evaluation of an antibacterial coating containing halogenated furanone compound-loaded poly(l-lactic acid) nanoparticles on microarc-oxidized titanium implants.

    PubMed

    Cheng, Yicheng; Gao, Bo; Liu, Xianghui; Zhao, Xianghui; Sun, Weige; Ren, Huifang; Wu, Jiang

    2016-01-01

    To prevent peri-implant infection, a new antibacterial coating containing a halogenated furanone compound, (Z-)-4-bromo-5-(bromomethylene)-2(5H)-furanone-loaded poly(l-lactic acid) nanoparticles, has been fabricated. The current study was designed to evaluate the preventive effect of the antibacterial coating under a simulated environment of peri-implant infection in vivo. Microarc-oxidized titanium implants treated with minocycline hydrochloride ointment were used as positive control group, and microarc-oxidized titanium implants without any treatment were used as blank control group. Three kinds of implants were implanted in dogs' mandibles, and the peri-implant infection was simulated by silk ligation and feeding high sugar diet. After 2-month implantation, the results showed that no significant differences were detected between the experimental and positive control groups (P>0.05), but the data of clinical measurements of the blank control group were significantly higher than those of the other two groups (P<0.05), and the bone-implant contact rate and ultimate interfacial strength were significantly lower than those of the other two groups (P<0.05). Scanning electron microscope observation and histological examination showed that more new bone was formed on the surface of the experimental and positive control groups. It can be concluded that the antibacterial coating fabricated on implants has remarkable preventive effect on peri-implant infection at the early stage.

  19. Effects of mechanical repetitive load on bone quality around implants in rat maxillae

    PubMed Central

    Uto, Yusuke; Nakano, Takayoshi; Ishimoto, Takuya; Inaba, Nao; Uchida, Yusuke; Sawase, Takashi

    2017-01-01

    Greater understanding and acceptance of the new concept “bone quality”, which was proposed by the National Institutes of Health and is based on bone cells and collagen fibers, are required. The novel protein Semaphorin3A (Sema3A) is associated with osteoprotection by regulating bone cells. The aims of this study were to investigate the effects of mechanical loads on Sema3A production and bone quality based on bone cells and collagen fibers around implants in rat maxillae. Grade IV-titanium threaded implants were placed at 4 weeks post-extraction in maxillary first molars. Implants received mechanical loads (10 N, 3 Hz for 1800 cycles, 2 days/week) for 5 weeks from 3 weeks post-implant placement to minimize the effects of wound healing processes by implant placement. Bone structures, bone mineral density (BMD), Sema3A production and bone quality based on bone cells and collagen fibers were analyzed using microcomputed tomography, histomorphometry, immunohistomorphometry, polarized light microscopy and birefringence measurement system inside of the first and second thread (designated as thread A and B, respectively), as mechanical stresses are concentrated and differently distributed on the first two threads from the implant neck. Mechanical load significantly increased BMD, but not bone volume around implants. Inside thread B, but not thread A, mechanical load significantly accelerated Sema3A production with increased number of osteoblasts and osteocytes, and enhanced production of both type I and III collagen. Moreover, mechanical load also significantly induced preferential alignment of collagen fibers in the lower flank of thread B. These data demonstrate that mechanical load has different effects on Sema3A production and bone quality based on bone cells and collagen fibers between the inside threads of A and B. Mechanical load-induced Sema3A production may be differentially regulated by the type of bone structure or distinct stress distribution, resulting in

  20. Effects of mechanical repetitive load on bone quality around implants in rat maxillae.

    PubMed

    Uto, Yusuke; Kuroshima, Shinichiro; Nakano, Takayoshi; Ishimoto, Takuya; Inaba, Nao; Uchida, Yusuke; Sawase, Takashi

    2017-01-01

    Greater understanding and acceptance of the new concept "bone quality", which was proposed by the National Institutes of Health and is based on bone cells and collagen fibers, are required. The novel protein Semaphorin3A (Sema3A) is associated with osteoprotection by regulating bone cells. The aims of this study were to investigate the effects of mechanical loads on Sema3A production and bone quality based on bone cells and collagen fibers around implants in rat maxillae. Grade IV-titanium threaded implants were placed at 4 weeks post-extraction in maxillary first molars. Implants received mechanical loads (10 N, 3 Hz for 1800 cycles, 2 days/week) for 5 weeks from 3 weeks post-implant placement to minimize the effects of wound healing processes by implant placement. Bone structures, bone mineral density (BMD), Sema3A production and bone quality based on bone cells and collagen fibers were analyzed using microcomputed tomography, histomorphometry, immunohistomorphometry, polarized light microscopy and birefringence measurement system inside of the first and second thread (designated as thread A and B, respectively), as mechanical stresses are concentrated and differently distributed on the first two threads from the implant neck. Mechanical load significantly increased BMD, but not bone volume around implants. Inside thread B, but not thread A, mechanical load significantly accelerated Sema3A production with increased number of osteoblasts and osteocytes, and enhanced production of both type I and III collagen. Moreover, mechanical load also significantly induced preferential alignment of collagen fibers in the lower flank of thread B. These data demonstrate that mechanical load has different effects on Sema3A production and bone quality based on bone cells and collagen fibers between the inside threads of A and B. Mechanical load-induced Sema3A production may be differentially regulated by the type of bone structure or distinct stress distribution, resulting in

  1. Early Implantation of Primary Prevention Implantable Cardioverter Defibrillators for Patients with Newly Diagnosed Severe Nonischemic Cardiomyopathy.

    PubMed

    Voskoboinik, Aleksandr; Bloom, Jason; Taylor, Andrew; Mariani, Justin

    2016-09-01

    Primary prevention implantable cardioverter defibrillators (ICDs) reduce mortality in selected patients with severe systolic dysfunction. Current guidelines suggest a 3- to 6-month waiting period before implantation. We retrospectively studied 29 consecutive patients with newly diagnosed nonischemic cardiomyopathy (NICM) who underwent primary prevention ICD implantation within 6 months of diagnosis between January 2008 and April 2014. Cardiac MRI (CMR) evaluated left ventricular ejection fraction (LVEF) and regional fibrosis preimplant. The primary end point was "failure to qualify for an ICD at 12 months postimplant," either due to LVEF ≥ 35% or deterioration necessitating mechanical support or transplantation, without appropriate ICD therapy. Secondary end points were appropriate and inappropriate ICD therapy. Baseline mean age was 44.2 ± 14.8 years and median LVEF 16.4%. Median time from diagnosis to implant was 32 days. At 12 months, 17 patients (58.6%) no longer qualified for an ICD, mainly due to LVEF improvement. At follow-up (mean 32.0 ± 20.6 months), three patients received appropriate therapy (one for ventricular fibrillation). All three had CMR late gadolinium enhancement (LGE) and nonsustained ventricular tachycardia (NSVT) preimplant. Cardiac resynchronization at implant predicted LVEF improvement. Early appropriate therapy, particularly for ventricular fibrillation, is infrequent for patients with very severe NICM who have ICDs implanted within 6 months of diagnosis. The majority of these patients would not qualify for an ICD at 12 months postinsertion. In the absence of a multimodality risk score, early ICD insertion should only be considered in selected cases (presence of LGE and NSVT). Wearable cardioverter defibrillators may have a role as a bridge to ICD decision. © 2016 Wiley Periodicals, Inc.

  2. Stress on external hexagon and Morse taper implants submitted to immediate loading

    PubMed Central

    Odo, Caroline H.; Pimentel, Marcele J.; Consani, Rafael L.X.; Mesquita, Marcelo F.; Nóbilo, Mauro A.A.

    2015-01-01

    Background/Aims This study aimed to evaluate the stress distribution around external hexagon (EH) and Morse taper (MT) implants with different prosthetic systems of immediate loading (distal bar (DB), casting technique (CT), and laser welding (LW)) by using photoelastic method. Methods Three infrastructures were manufactured on a model simulating an edentulous lower jaw. All models were composed by five implants (4.1 mm × 13.0 mm) simulating a conventional lower protocol. The samples were divided into six groups. G1: EH implants with DB and acrylic resin; G2: EH implants with titanium infrastructure CT; G3: EH implants with titanium infrastructure attached using LW; G4: MT implants with DB and acrylic resin; G5: MT implants with titanium infrastructure CT; G6: MT implants with titanium infrastructure attached using LW. After the infrastructures construction, the photoelastic models were manufactured and a loading of 4.9 N was applied in the cantilever. Five pre-determined points were analyzed by Fringes software. Results Data showed significant differences between the connection types (p < 0.0001), and there was no significant difference among the techniques used for infrastructure. Conclusion The reduction of the stress levels was more influenced by MT connection (except for CT). Different bar types submitted to immediate loading not influenced stress concentration. PMID:26605142

  3. Load Transfer Characteristics of Various Designs of Three-Implant-Retained Mandibular Overdentures.

    PubMed

    Tokar, Emre; Uludag, Bulent

    2015-01-01

    Many different attachment systems (eg, bars, studs, magnets, telescopic copings) have been used to retain overdentures. The current study aimed to investigate the load transfer characteristics and to compare the stress levels of four attachment designs for mandibular overdentures retained by one central implant and two inclined distal implants. Photoelastic mandibular models fabricated with three screw-type implants (Tapered Screw-Vent, 3.75 × 13 mm) were placed in the parasymphyseal area. The center implant was vertically oriented to the midline, and the other implants were embedded in the canine areas with a 20-degree angulation relative to the center implant. Four overdentures with different attachment designs (bar, bar/ball, bar/distally placed Rk-1s, and Locators) were studied in the context of this model. Vertical loads (100 N) were applied to the central fossa of the right first molar area of each overdenture. Stress levels that developed in the denture-bearing areas and around the implants were observed photoelastically and evaluated visually. The studied attachment designs showed low and moderate stress levels. The greatest stress was found with the bar/ball design, while the lowest stress levels were observed with the Locator attachment design. Stresses were concentrated on the loaded side for each design. All tested designs experienced moderate stress around the posterior edentulous area. None of the designs experienced more than moderate stress. The lowest stress was noted with the Locator attachments, which transmitted little discernible stress around the implants.

  4. A Randomized Case-Series Study Comparing the Stability of Implant with Two Different Surfaces Placed in Fresh Extraction Sockets and Immediately Loaded

    PubMed Central

    Vanden Bogaerde, Leonardo; Sennerby, Lars

    2016-01-01

    Background. Hydrophilic and moderately rough implant surfaces have been proposed to enhance the osseointegration response. Aim. The aim of this study was to compare early changes of stability for two implants with identical macrodesign but with different surface topographies. Materials and Methods. In 11 patients, a total of 22 implants (11 bimodal (minimally rough, control) and 11 proactive (moderately rough and hydrophilic, test), Neoss Ltd., Harrogate, UK) were immediately placed into fresh extraction sockets and immediately loaded. The peak insertion torque (IT) was measured in Ncm at placement. Resonance Frequency Analysis (RFA) measurements were made at baseline and 2, 4, 6, and 12 weeks after surgery. Results. The two implant types showed similar IT and RFA values at placement (NS). A dip of RFA values after 2 weeks followed by an increase was observed, where the test implant showed a less pronounced decrease and a more rapid recovery than the control implant. The test implants were significantly more stable than the control ones after 12 weeks. Conclusions. The results from the present study indicated that the hydrophilic and rougher test implant was more resistant to immediate loading and showed a significantly higher stability than the smoother control implant after 12 weeks. PMID:27042180

  5. Does implant coating with antibacterial-loaded hydrogel reduce bacterial colonization and biofilm formation in vitro?

    PubMed

    Drago, Lorenzo; Boot, Willemijn; Dimas, Kostantinos; Malizos, Kostantinos; Hänsch, Gertrud M; Stuyck, Jos; Gawlitta, Debby; Romanò, Carlo L

    2014-11-01

    Implant-related infections represent one of the most severe complications in orthopaedics. A fast-resorbable, antibacterial-loaded hydrogel may reduce or prevent bacterial colonization and biofilm formation of implanted biomaterials. We asked: (1) Is a fast-resorbable hydrogel able to deliver antibacterial compounds in vitro? (2) Can a hydrogel (alone or antibacterial-loaded) coating on implants reduce bacterial colonization? And (3) is intraoperative coating feasible and resistant to press-fit implant insertion? We tested the ability of Disposable Antibacterial Coating (DAC) hydrogel (Novagenit Srl, Mezzolombardo, Italy) to deliver antibacterial agents using spectrophotometry and a microbiologic assay. Antibacterial and antibiofilm activity were determined by broth microdilution and a crystal violet assay, respectively. Coating resistance to press-fit insertion was tested in rabbit tibias and human femurs. Complete release of all tested antibacterial compounds was observed in less than 96 hours. Bactericidal and antibiofilm effect of DAC hydrogel in combination with various antibacterials was shown in vitro. Approximately 80% of the hydrogel coating was retrieved on the implant after press-fit insertion. Implant coating with an antibacterial-loaded hydrogel reduces bacterial colonization and biofilm formation in vitro. A fast-resorbable, antibacterial-loaded hydrogel coating may help prevent implant-related infections in orthopaedics. However, further validation in animal models and properly controlled human studies is required.

  6. Effect of Cyclic Loading on Micromotion at the Implant-Abutment Interface.

    PubMed

    Karl, Matthias; Taylor, Thomas D

    2016-01-01

    Cyclic loading may cause settling of abutments mounted on dental implants, potentially affecting screw joint stability and implant-abutment micromotion. It was the goal of this in vitro study to compare micromotion of implant-abutment assemblies before and after masticatory simulation. Six groups of abutments (n = 5) for a specific tissue-level implant system with an internal octagon were subject to micromotion measurements. The implant-abutment assemblies were loaded in a universal testing machine, and an apparatus and extensometers were used to record displacement. This was done twice, in the condition in which they were received from the abutment manufacturer and after simulated loading (100,000 cycles; 100 N). Statistical analysis was based on analysis of variance, two-sample t tests (Welch tests), and Pearson product moment correlation (α = .05). The mean values for micromotion ranged from 33.15 to 63.41 μm and from 30.03 to 42.40 μm before and after load cycling. The general trend toward reduced micromotion following load cycling was statistically significant only for CAD/CAM zirconia abutments (P = .036) and for one type of clone abutment (P = .012), with no significant correlation between values measured before and after cyclic loading (Pearson product moment correlation; P = .104). While significant differences in micromotion were found prior to load cycling, no significant difference among any of the abutment types tested could be observed afterward (P > .05 in all cases). A quantifiable settling effect at the implant-abutment interface seems to result from cyclic loading, leading to a decrease in micromotion. This effect seems to be more pronounced in low-quality abutments. For the implant system tested in this study, retightening of abutment screws is recommended after an initial period of clinical use.

  7. 2D FEA of evaluation of micromovements and stresses at bone-implant interface in immediately loaded tapered implants in the posterior maxilla

    PubMed Central

    Desai, Shrikar R.; Singh, Rika; Karthikeyan, I.

    2013-01-01

    Aim: The aim of the study is to evaluate the influence implant length on stress distribution at bone implant interface in single immediately loaded implants when placed in D4 bone quality. Materials and Methods: A 2-dimensional finite element models were developed to simulate two types of implant designs, standard 3.75 mm–diameter tapered body implants of 6 and 10 mm lengths. The implants were placed in D4 bone quality with a cortical bone thickness of 0.5 mm. The implant design incorporated microthreads at the crestal part and the rest of the implant body incorporated Acme threads. The Acme thread form has a 29° thread angle with a thread height half of the pitch; the apex and valley are flat. A 100 N of force was applied vertically and in the oblique direction (at an angle of 45°) to the long axis of the implants. The respective material properties were assigned. Micro-movements and stresses at the bone implant interface were evaluated. Results: The results of total deformation (micro-movement) and Von mises stress were found to be lower for tapered long implant (10 mm) than short implant (6 mm) while using both vertical as well as oblique loading. Conclusion: Short implants can be successfully placed in poor bone quality under immediate loading protocol. The novel approach of the combination of microthreads at the crestal portion and acme threads for body portion of implant fixture gave promising results. PMID:24174759

  8. 2D FEA of evaluation of micromovements and stresses at bone-implant interface in immediately loaded tapered implants in the posterior maxilla.

    PubMed

    Desai, Shrikar R; Singh, Rika; Karthikeyan, I

    2013-09-01

    The aim of the study is to evaluate the influence implant length on stress distribution at bone implant interface in single immediately loaded implants when placed in D4 bone quality. A 2-dimensional finite element models were developed to simulate two types of implant designs, standard 3.75 mm-diameter tapered body implants of 6 and 10 mm lengths. The implants were placed in D4 bone quality with a cortical bone thickness of 0.5 mm. The implant design incorporated microthreads at the crestal part and the rest of the implant body incorporated Acme threads. The Acme thread form has a 29° thread angle with a thread height half of the pitch; the apex and valley are flat. A 100 N of force was applied vertically and in the oblique direction (at an angle of 45°) to the long axis of the implants. The respective material properties were assigned. Micro-movements and stresses at the bone implant interface were evaluated. The results of total deformation (micro-movement) and Von mises stress were found to be lower for tapered long implant (10 mm) than short implant (6 mm) while using both vertical as well as oblique loading. Short implants can be successfully placed in poor bone quality under immediate loading protocol. The novel approach of the combination of microthreads at the crestal portion and acme threads for body portion of implant fixture gave promising results.

  9. Immediate loading of unsplinted implants in the anterior mandible for overdentures: 3-year results.

    PubMed

    Roe, Phillip; Kan, Joseph Y K; Rungcharassaeng, Kitichai; Lozada, Jaime L

    2011-01-01

    This 3-year study evaluated the implant survival rate, peri-implant tissue response, prosthetic maintenance, and prosthetic complications in a series of patients who received two immediately loaded unsplinted threaded implants to retain a mandibular overdenture. Eight completely edentulous patients were evaluated clinically and radiographically immediately after implant placement, at 3 months, and at 1, 2, and 3 years after implant placement. Data were analyzed using repeated-measures one-way analysis of variance and the Wilcoxon signed rank test at a significance level of α = .05. At 3 years, all implants remained osseointegrated (16/16), with an overall mean marginal bone change of -0.58 ± 0.39 mm and a mean Periotest value of -7.19 ± 0.54. The modified Plaque Index scores showed marked improvement in oral hygiene during the first year, but some relapse was observed thereafter. Prosthetic maintenance and complications included replacement of the attachment inserts, abutment loosening, dislodgement of the attachment housing, overdenture reline, denture tooth fracture, and overdenture base fracture. This 3-year study suggests that, despite less than ideal oral hygiene and a high incidence of complete/partial fracture of overdentures, favorable implant survival rate and peri-implant tissue responses can be achieved in mandibular overdentures retained with two immediately loaded unsplinted threaded implants.

  10. Pre-load on oral implants after screw tightening fixed full prostheses: an in vivo study.

    PubMed

    Duyck, J; Van Oosterwyck, H; Vander Sloten, J; De Cooman, M; Puers, R; Naert, I

    2001-03-01

    The fit of implant supported fixed prostheses is said to be of clinical concern because of the rigid fixation of an oral implant in its surrounding bone. The influence of the torque sequence of the set screws during fixation of implant supported fixed full prostheses on the final pre-load was investigated in vitro. No significant effect of the torque sequence of the set screws on the final pre-load was observed. The main objective of this study was to quantify and qualify the pre-load in vivo on implants supporting a fixed full prosthesis. This was performed when the prostheses were supported by all five or six implants and was repeated when the prostheses were supported by only four and three implants. A total of 13 patients with a fixed full implant supported prosthesis were selected. The existing abutments were changed for strain gauged abutments. After tightening the set screws with a torque of 10 N cm, the pre-load conditions were registered. The average (SEM) axial forces and bending moments in case of five or six, four and three supporting implants were 323 N (43 N), 346 N (59 N), 307 N (60 N) 21 N cm (3 N cm) and 21 N cm (2 N cm), 23 N cm (5 N cm), respectively. In addition, the pre-load was registered after fixation of a machined gold cylinder, as delivered by the manufacturer, on each of the supporting implants, representing the 'optimal fit' situation. The corresponding average (SEM) axial forces and bending moments in case of five or six, four and three supporting implants were 426 N (36 N), 405 N (40 N), 413 N (46 N) and 8 N cm (1 N cm), 8 N cm (1 N cm), 8 N cm (1 N cm), respectively. The induced axial forces after tightening the prostheses were significantly lower then after tightening the gold cylinder in case of five or six supporting implants (P < 0.02). The induced bending moments after tightening the prostheses were statistically significantly higher (P < 0.0001) then after tightening the gold cylinder in all test conditions (five or six, four or

  11. Influence of occlusal loading on peri-implant clinical parameters. A pilot study

    PubMed Central

    Pellicer-Chover, Hilario; Viña-Almunia, José; Romero-Millán, Javier; Peñarrocha-Oltra, David; Peñarrocha-Diago, María

    2014-01-01

    Objectives: To investigate the relation between occlusal loading and peri-implant clinical parameters (probing depth, bleeding on probing, gingival retraction, width of keratinized mucosa, and crevicular fluid volume) in patients with implant-supported complete fixed prostheses in both arches. Material and Methods: This clinical study took place at the University of Valencia (Spain) dental clinic. It included patients attending the clinic for regular check-ups during at least 12 months after rehabilitation of both arches with implant-supported complete fixed ceramo-metallic prostheses. One study implant and one control implant were established for each patient using the T-Scan®III computerized system (Tesco, South Boston, USA). The maxillary implant closest to the point of maximum occlusal loading was taken as the study implant and the farthest (with least loading) as the control. Occlusal forces were registered with the T-Scan® III and then occlusal adjustment was performed to distribute occlusal forces correctly. Peri-implant clinical parameters were analyzed in both implants before and two and twelve months after occlusal adjustment. Results: Before occlusal adjustment, study group implants presented a higher mean volume of crevicular fluid (51.3±7.4 UP) than the control group (25.8±5.5 UP), with statistically significant difference. Two months after occlusal adjustment, there were no significant differences between groups (24.6±3.8 UP and 26±4.5 UP respectively) (p=0.977). After twelve months, no significant differences were found between groups (24.4±11.1 UP and 22.5±8.9 UP respectively) (p=0.323). For the other clinical parameters, no significant differences were identified between study and control implants at any of the study times (p>0.05). Conclusions: Study group implants receiving higher occlusal loading presented significantly higher volumes of crevicular fluid than control implants. Crevicular fluid volumes were similar in both groups two and

  12. Effect of cyclic load on vertical misfit of prefabricated and cast implant single abutment

    PubMed Central

    DE JESUS TAVAREZ, Rudys Rodolfo; BONACHELA, Wellington Cardoso; XIBLE, Anuar Antônio

    2011-01-01

    Objective The purpose of this in vitro study was to evaluate misfit alterations at the implant/abutment interface of external and internal connection implant systems when subjected to cyclic loading. Material and Methods Standard metal crowns were fabricated for 5 groups (n=10) of implant/abutment assemblies: Group 1, external hexagon implant and UCLA cast-on premachined abutment; Group 2, internal hexagon implant and premachined abutment; Group 3, internal octagon implant and prefabricated abutment; Group 4, external hexagon implant and UCLA cast-on premachined abutment; and Group 5, external hexagon implant and Ceraone abutment. For groups 1, 2, 3 and 5, the crowns were cemented on the abutments and in group 4 crowns were screwed directly on the implant. The specimens were subjected to 500,000 cycles at 19.1 Hz of frequency and non-axial load of 133 N in a MTS 810 machine. The vertical misfit (μm) at the implant/abutment interface was evaluated before (B) and after (A) application of the cyclic loading. Data were analyzed statistically by using two-away ANOVA and Tukey’s post-hoc test (p<0.05). Results Before loading values showed no difference among groups 2 (4.33±3.13), 3 (4.79±3.43) and 5 (3.86±4.60); between groups 1 (12.88±6.43) and 4 (9.67±3.08), and among groups 2, 3 and 4. However, groups 1 and 4 were significantly different from groups 2, 3 and 5. After loading values of groups 1 (17.28±8.77) and 4 (17.78±10.99) were significantly different from those of groups 2 (4.83±4.50), 3 (8.07±4.31) and 5 (3.81±4.84). There was a significant increase in misfit values of groups 1, 3 and 4 after cyclic loading, but not for groups 2 and 5. Conclusion The cyclic loading and type of implant/abutment connection may develop a role on the vertical misfit at the implant/abutment interface. PMID:21437464

  13. Removal torque evaluation of three different abutment screws for single implant restorations after mechanical cyclic loading.

    PubMed

    Paepoemsin, T; Reichart, P A; Chaijareenont, P; Strietzel, F P; Khongkhunthian, P

    2016-01-01

    The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer's recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, P<.05). After cyclic loading, removal torque in all groups decreased significantly (P<.05). Group C revealed significantly less removal torque than groups A and B (P<.005). Tensile force in all groups significantly increased after cyclic loading (P<.05), group A had significantly less tensile force than groups B and C (P<.005). Removal torque reduced significantly after cyclic loading. Before cyclic loading, tapered screws maintained more preload than did flat head screws. After cyclic loading, tapered and flat head screws maintained even amounts of preload. The tensile force that dislodged abutment from implant fixture increased immensely after cyclic loading.

  14. Removal torque evaluation of three different abutment screws for single implant restorations after mechanical cyclic loading

    PubMed Central

    PAEPOEMSIN, T.; REICHART, P. A.; CHAIJAREENONT, P.; STRIETZEL, F. P.; KHONGKHUNTHIAN, P.

    2016-01-01

    SUMMARY Purpose The aim of this study was to evaluate the removal torque of three different abutment screws and pull out strength of implant-abutment connection for single implant restorations after mechanical cyclic loading. Methods The study was performed in accordance with ISO 14801:2007. Three implant groups (n=15) were used: group A, PW Plus® with flat head screw; group B, PW Plus® with tapered screw; and group C, Conelog® with flat head screw. All groups had the same implant-abutment connection feature: cone with mandatory index. All screws were tightened with manufacturer’s recommended torque. Ten specimens in each group underwent cyclic loading (1×106 cycles, 10 Hz, and 250 N). Then, all specimens were un-tightened, measured for the removal torque, and underwent a tensile test. The force that dislodged abutment from implant fixture was recorded. The data were analysed using independent sample t-test, ANOVA and Tukey HSD test. Results Before cyclic loading, removal torque in groups A, B and C were significantly different (B> A> C, P<.05). After cyclic loading, removal torque in all groups decreased significantly (P<.05). Group C revealed significantly less removal torque than groups A and B (P<.005). Tensile force in all groups significantly increased after cyclic loading (P<.05), group A had significantly less tensile force than groups B and C (P<.005). Conclusions Removal torque reduced significantly after cyclic loading. Before cyclic loading, tapered screws maintained more preload than did flat head screws. After cyclic loading, tapered and flat head screws maintained even amounts of preload. The tensile force that dislodged abutment from implant fixture increased immensely after cyclic loading. PMID:28042450

  15. Cognitive load effects on early visual perceptual processing.

    PubMed

    Liu, Ping; Forte, Jason; Sewell, David; Carter, Olivia

    2018-05-01

    Contrast-based early visual processing has largely been considered to involve autonomous processes that do not need the support of cognitive resources. However, as spatial attention is known to modulate early visual perceptual processing, we explored whether cognitive load could similarly impact contrast-based perception. We used a dual-task paradigm to assess the impact of a concurrent working memory task on the performance of three different early visual tasks. The results from Experiment 1 suggest that cognitive load can modulate early visual processing. No effects of cognitive load were seen in Experiments 2 or 3. Together, the findings provide evidence that under some circumstances cognitive load effects can penetrate the early stages of visual processing and that higher cognitive function and early perceptual processing may not be as independent as was once thought.

  16. Zirconia-implant-supported all-ceramic crowns withstand long-term load: a pilot investigation.

    PubMed

    Kohal, Ralf-J; Klaus, Gerold; Strub, Jörg R

    2006-10-01

    The purpose of this pilot investigation was to test whether zirconia implants restored with different all-ceramic crowns would fulfill the biomechanical requirements for clinical use. Therefore, all-ceramic Empress-1 and Procera crowns were cemented on zirconia implants and exposed to the artificial mouth. Afterwards, the fracture strength of the all-ceramic implant-crown systems was evaluated. Conventional titanium implants restored with porcelain-fused-to-metal (PFM) crowns served as controls. Sixteen titanium implants with 16 PFM crowns and 32 zirconia implants with 16 Empress-1 crowns and 16 Procera crowns each--i.e., three implant-crown groups--were used in this investigation. The titanium implants were fabricated using the ReImplant system and the zirconia implants using the Celay system. The upper left central incisor served as a model for the fabrication of the implants and the crowns. Eight samples of each group were submitted to a long-term load test in the artificial mouth (1.2 million chewing cycles). Subsequently, a fracture strength test was performed with seven of the eight crowns. The remaining eight samples of each group were not submitted to the long-term load in the artificial mouth but were fracture-tested immediately. One loaded and one unloaded sample of each group were evaluated regarding the marginal fit of the crowns. All test samples survived the exposure to the artificial mouth. Three Empress-1 crowns showed cracks in the area of the loading steatite ball. The values for the fracture load in the titanium implant-PFM crown group without artificial loading ranged between 420 and 610 N (mean: 531.4 N), between 460 and 570 N (mean: 512.9 N) in the Empress-1 crown group, and in the Procera crown group the values were between 475 and 700 N (mean: 575.7 N) when not loaded artificially. The results when the specimens were loaded artificially with 1.2 million cycles were as follows: the titanium implant-PFM crowns fractured between 440 and 950 N

  17. Parafunctional loading and occlusal device on stress distribution around implants: A 3D finite element analysis.

    PubMed

    Borges Radaelli, Manuel Tomás; Idogava, Henrique Takashi; Spazzin, Aloisio Oro; Noritomi, Pedro Yoshito; Boscato, Noéli

    2018-04-30

    An occlusal device is frequently recommended for patients with bruxism to protect implant-supported restorations and prevent marginal bone loss. Scientific evidence to support this treatment is lacking. The purpose of this 3-dimensional (3D) finite element study was to evaluate the influence of an acrylic resin occlusal device, implant length, and insertion depth on stress distribution with functional and parafunctional loadings. Computer-aided design software was used to construct 8 models. The models were composed of a mandibular bone section including the second premolar and first and second molars. Insertion depths (bone level and 2 mm subcrestal) were simulated at the first molar. Three natural antagonist maxillary teeth and the placement or not of an occlusal device were simulated. Functional (200-N axial and 10-N oblique) and parafunctional (1000-N axial and 25-N oblique) forces were applied. Finite element analysis (FEA) was used to determine the maximum principal stress for the cortical and trabecular bone and von Mises for implant and prosthetic abutment. Stress concentration was observed at the abutment-implant and the implant-bone interfaces. Occlusal device placement changed the pattern of stress distribution and reduced stress levels from parafunctional loading in all structures, except in the trabecular bone. Implants with subcrestal insertion depths had reduced stress at the implant-abutment interface and cortical bone around the implant abutment, while the stress increased in the bone in contact with the implant. Parafunctional loading increased the stress levels in all structures when compared with functional loading. An occlusal device resulted in the lowest stress levels at the abutment and implant and the most favorable stress distribution between the cortical and trabecular bone. Under parafunctional loading, an occlusal device was more effective in reducing stress distribution for longer implants inserted at bone level. Subcrestally, implant

  18. In situ microradioscopy and microtomography of fatigue-loaded dental two-piece implants.

    PubMed

    Wiest, Wolfram; Zabler, Simon; Rack, Alexander; Fella, Christian; Balles, Andreas; Nelson, Katja; Schmelzeisen, Rainer; Hanke, Randolf

    2015-11-01

    Synchrotron real-time radioscopy and in situ microtomography are the only techniques providing direct visible information on a micrometre scale of local deformation in the implant-abutment connection (IAC) during and after cyclic loading. The microgap formation at the IAC has been subject to a number of studies as it has been proposed to be associated with long-term implant success. The next step in this scientific development is to focus on the in situ fatigue procedure of two-component dental implants. Therefore, an apparatus has been developed which is optimized for the in situ fatigue analysis of dental implants. This report demonstrates both the capability of in situ radioscopy and microtomography at the ID19 beamline for the study of cyclic deformation in dental implants. The first results show that it is possible to visualize fatigue loading of dental implants in real-time radioscopy in addition to the in situ fatigue tomography. For the latter, in situ microtomography is applied during the cyclic loading cycles in order to visualize the opening of the IAC microgap. These results concur with previous ex situ studies on similar systems. The setup allows for easily increasing the bending force, to simulate different chewing situations, and is, therefore, a versatile tool for examining the fatigue processes of dental implants and possibly other specimens.

  19. Immediate functional loading of single implants: a multicenter study with 4 years of follow-up

    PubMed Central

    Raes, Filiep; Eccellente, Tammaro; Lenzi, Carolina; Ortolani, Michele; Luongo, Giuseppe; Mangano, Carlo; Mangano, Francesco

    2018-01-01

    Background. In the current scientific literature there are only few studies on the immediate functional loading of single implants. The aim of the present present study was to evaluate the 4-year survival rate, complication rate and peri-implant marginal bone loss (PIMBL) of immediately loaded single implants inserted in healed ridges and fresh post-extraction sites. Methods. Six centers were involved in this prospective study. The surgical and prosthetic protocol was defined in detail, before the start of recruiting patients. Recruitment of patients and performance of surgeries took place between February 2012 and February 2013. Criteria for inclusion were single-tooth gaps in healed ridges and fresh post-extraction sockets. All the fixtures (Anyridge®, Megagen Corporation, Gyeongbuk, South Korea) were functionally loaded immediately after insertion and followed for a period of 4 years. Outcome measures were implant survival, complications and PIMBL. Results. Forty-six patients (18‒73 years of age) were selected. In total, 57 fixtures were placed (10 in fresh post-extraction sockets). After 4 years of functional loading, only one fixture was lost; therefore, high survival rates (97.6% patient-based; 98.1% implant-based) were reported. In addition, a limited incidence of biologic (4.8% patient-based; 3.8% implant-based) and prosthetic (9.7% patient-based; 7.6% implant-based) complications was reported. The overall 4-year PIMBL amounted to 0.38±0.21 mm (healed ridges: 0.4±0.21 mm; fresh post-extraction sockets: 0.33±0.20 mm). Conclusion. Loading single implants immediately seems to be a highly successful treatment modality. However, long-term data are needed to confirm these positive outcomes. PMID:29732018

  20. Comparative Microstrain Study of Internal Hexagon and Plateau Design of Short Implants Under Vertical Loading.

    PubMed

    Nishioka, Renato Sussumu; Rodrigues, Vinicius Anéas; De Santis, Leandro Ruivo; Nishioka, Gabriela Nogueira De Melo; Santos, Vivian Mayumi Miyazaki; Souza, Francisley Ávila

    2016-02-01

    To quantify microstrain development during axial loading using strain gauge analysis for short implants, varying the type of fixture-abutment joint and thread design. An internal hexagon implant (4 × 8 mm) and a plateau design implant (4 × 8 mm) were embedded on the center of 10 polyurethane blocks with dimensions of 190 × 30 × 12 mm. The respective abutments were screwed onto the implants. Four strain gauges (SGs) were bonded onto the surface of each block, and 4 vertical SGs were bonded onto the side of each block. Axial load of 30 kgf was applied for 10 seconds in the center of each implant. The data were analyzed statistically by analysis of variance for repeated measures and Tukey test (P < 0.05). The interaction between implant and region factors have been statistically significant (P = 0.0259). Tukey test revealed a difference on plateau's horizontal region. The cervical region presented higher microstrain values, when compared with the medium and apical regions of the implants. Within the purpose of the study, the type of fixture-abutment joint is a relevant factor to affect the amount of stress/strain in bone simulation. The microstrain development was concentrated on the cervical region of the implant.

  1. Effect of anabolic implants on adrenal cortisol synthesis in feedlot beef cattle implanted early or late in the finishing phase.

    PubMed

    Gifford, C A; Branham, K A; Ellison, J O; Gómez, B I; Lemley, C O; Hart, C G; Krehbiel, C R; Bernhard, B C; Maxwell, C L; Goad, C L; Hallford, D M; Hernandez Gifford, J A

    2015-01-01

    Implantation of anabolic steroids to increase growth rate in beef cattle impacts adrenal glucocorticoid production. The mechanism by which combination androgen and estrogen implants reduce cortisol biosynthesis in heifers is not clear. The objective of this study was to identify whether pituitary or adrenal gene expression and liver enzyme activity may contribute to altered serum cortisol concentrations in heifers receiving a combination implant. On d 0 of a 122-d finishing phase, 187 predominantly Angus heifers (361 kg) approximately 14 months old were randomly assigned to one of three implant groups: (1) non-implanted control, (2) implanted at the beginning of the finishing phase (d 0; early implant) with a combination implant (200mg TBA+20mg E2; Revalor 200®), and (3) implanted during the late stage of the finishing phase (d 56; late implant) with Revalor 200®. At d 56, body weight (BW) was greater (P<0.0001) for the early implanted heifers (456 ± 1.9 kg) compared to 437 and 435 (± 1.8) kg for control and late implanted heifers, respectively. Final BW (d 122) was similar between both implanted groups and heavier than non-implanted controls (P<0.0001). Serum cortisol was similar among groups at d 0 (P=0.86) however, by d 28 heifers receiving the combination implant had reduced (P<0.05) serum cortisol concentrations (31.2 ng/mL) compared to controls (49.4 ng/mL) and late (48.2 ng/mL) groups. On d 84 cortisol was similar (P=0.75) among implanted heifers and was less (P<0.01) than non-implanted heifers. Expression of pituitary and adrenal genes involved in glucocorticoid synthesis was evaluated at d 28/29 or 84/85; however, despite decreased serum cortisol in implanted heifers, no change in mRNA expression was demonstrated. Liver CYP3A enzyme activity at d 28/29 was decreased 59% in early implanted heifers compared to control heifers (P=0.01). Additionally, at d 84/85 AKR1C activity was greatest (P=0.01) in control heifers compared to both implanted groups. Data

  2. Strain Distribution in a Kennedy Class I Implant Assisted Removable Partial Denture under Various Loading Conditions

    PubMed Central

    Shahmiri, Reza; Aarts, John M.; Bennani, Vincent; Swain, Michael V.

    2013-01-01

    Purpose. This in vitro study investigates how unilateral and bilateral occlusal loads are transferred to an implant assisted removable partial denture (IARPD). Materials and Methods. A duplicate model of a Kennedy class I edentulous mandibular arch was made and then a conventional removable partial denture (RPD) fabricated. Two Straumann implants were placed in the second molar region, and the prosthesis was modified to accommodate implant retained ball attachments. Strain gages were incorporated into the fitting surface of both the framework and acrylic to measure microstrain (μStrain). The IARPD was loaded to 120Ns unilaterally and bilaterally in three different loading positions. Statistical analysis was carried out using SPSS version 18.0 (SPSS, Inc., Chicago, IL, USA) with an alpha level of 0.05 to compare the maximum μStrain values of the different loading conditions. Results. During unilateral and bilateral loading the maximum μStrain was predominantly observed in a buccal direction. As the load was moved anteriorly the μStrain increased in the mesial area. Unilateral loading resulted in a twisting of the structure and generated a strain mismatch between the metal and acrylic surfaces. Conclusions. Unilateral loading created lateral and vertical displacement of the IARPD. The curvature of the dental arch resulted in a twisting action which intensified as the unilateral load was moved anteriorly. PMID:23737788

  3. Early Sign Language Exposure and Cochlear Implantation Benefits.

    PubMed

    Geers, Ann E; Mitchell, Christine M; Warner-Czyz, Andrea; Wang, Nae-Yuh; Eisenberg, Laurie S

    2017-07-01

    Most children with hearing loss who receive cochlear implants (CI) learn spoken language, and parents must choose early on whether to use sign language to accompany speech at home. We address whether parents' use of sign language before and after CI positively influences auditory-only speech recognition, speech intelligibility, spoken language, and reading outcomes. Three groups of children with CIs from a nationwide database who differed in the duration of early sign language exposure provided in their homes were compared in their progress through elementary grades. The groups did not differ in demographic, auditory, or linguistic characteristics before implantation. Children without early sign language exposure achieved better speech recognition skills over the first 3 years postimplant and exhibited a statistically significant advantage in spoken language and reading near the end of elementary grades over children exposed to sign language. Over 70% of children without sign language exposure achieved age-appropriate spoken language compared with only 39% of those exposed for 3 or more years. Early speech perception predicted speech intelligibility in middle elementary grades. Children without sign language exposure produced speech that was more intelligible (mean = 70%) than those exposed to sign language (mean = 51%). This study provides the most compelling support yet available in CI literature for the benefits of spoken language input for promoting verbal development in children implanted by 3 years of age. Contrary to earlier published assertions, there was no advantage to parents' use of sign language either before or after CI. Copyright © 2017 by the American Academy of Pediatrics.

  4. Effect on Bone Architecture of Marginal Grooves in Dental Implants Under Occlusal Loaded Conditions in Beagle Dogs.

    PubMed

    Kato, Hatsumi; Kuroshima, Shinichiro; Inaba, Nao; Uto, Yusuke; Sawase, Takashi

    2018-02-01

    The aim of this study was to clarify whether marginal grooves on dental implants affect osseointegration, bone structure, and the alignment of collagen fibers to determine bone quality under loaded conditions. Anodized Ti-6Al-4V alloy dental implants, with and without marginal grooves (test and control implants, respectively), were used (3.7 × 8.0 mm). Fourth premolars and first molars of 6 beagle mandibles were extracted. Two control and test implants were placed in randomly selected healed sites at 12 weeks after tooth extraction. Screw-retained single crowns for first molars were fabricated. Euthanasia was performed at 8 weeks after the application of occlusal forces. Implant marginal bone level, bone to implant contact (BIC), bone structure around dental implants, and the alignment of collagen fibers determining bone quality were analyzed. The marginal bone level in test implants was significantly higher than that in control implants. Occlusal forces significantly increased BIC in test implants ( P = .007), whereas BIC did not change in control implants, irrespective of occlusal forces ( P = .303). Moreover, occlusal forces significantly increased BIC in test implants compared with control implants ( P = .032). Additionally, occlusal forces preferentially aligned collagen fibers in test implants, but not control implants. Hence, marginal grooves on dental implants have positive effects on increased osseointegration and adapted bone quality based on the preferential alignment of collagen fibers around dental implants under loaded conditions.

  5. Assessment of Various Risk Factors for Success of Delayed and Immediate Loaded Dental Implants: A Retrospective Analysis.

    PubMed

    Prasant, M C; Thukral, Rishi; Kumar, Sachin; Sadrani, Sannishth M; Baxi, Harsh; Shah, Aditi

    2016-10-01

    Ever since its introduction in 1977, a minimum of few months of period is required for osseointegration to take place after dental implant surgery. With the passage of time and advancements in the fields of dental implant, this healing period is getting smaller and smaller. Immediate loading of dental implants is becoming a very popular procedure in the recent time. Hence, we retrospectively analyzed the various risk factors for the failure of delayed and immediate loaded dental implants. In the present study, retrospective analysis of all the patients was done who underwent dental implant surgeries either by immediate loading procedure or by delayed loading procedures. All the patients were divided broadly into two groups with one group containing patients in which delayed loaded dental implants were placed while other consisted of patients in whom immediate loaded dental implants were placed. All the patients in whom follow-up records were missing and who had past medical history of any systemic diseases were excluded from the present study. Evaluation of associated possible risk factors was done by classifying the predictable factors as primary and secondary factors. All the results were analyzed by Statistical Package for the Social Sciences (SPSS) software. Kaplan-Meier survival analyses and chi-square test were used for assessment of level of significance. In delayed and immediate group of dental implants, mean age of the patients was 54.2 and 54.8 years respectively. Statistically significant results were obtained while comparing the clinical parameters of the dental implants in both the groups while demographic parameters showed nonsignificant correlation. Significant higher risk of dental implant failure is associated with immediate loaded dental implants. Tobacco smoking, shorter implant size, and other risk factors play a significant role in predicting the success and failure of dental implants. Delayed loaded dental implant placement should be preferred

  6. Survival of Implants in Immediate Extraction Sockets of Anterior Teeth: Early Clinical Results

    PubMed Central

    Sabir, Mohammad

    2015-01-01

    Background The aims and objectives of this study were placement of implants in freshly extracted sockets of anterior teeth and to evaluate the implant stability, peri-implant radiolucency and gingival inflammation around implant over a short period of 30 months. Materials and Methods A total of 12 patients (8 male and 4 female), ranging in the age from 20 to 50 years, from March 2007 to June 2007, were evaluated for immediate implant placement into 22 fresh extraction sockets. Only maxillary and mandibular anterior teeth/roots (central incisors, lateral incisors and canines) were considered for replacement with implants. One piece implant with integrated abutment and integrated surface, non-submerged, threaded and tapered at apical 5 mm, sand-blasted and acid etched surfaced implants (HI-TEC TRX-OP Implants of Life Care Company) were used. Results The mobility was not present in any of the implants at all the follow up visits. There were 2 implants at 6 month, 1 implant at 12 month, 1 implant at 18 month visits, showing peri-implant radiolucency at some sites at bone to implant contact site. Severe gingival inflammation was not observed in any of the implant site. At every follow-up visit, every implant met the criteria of success and none was found to be failed over a 30 months duration i.e. 100% success rate was achieved by implants in immediate extraction socket. Conclusion The success rate of implant survival in this study was found 100%. These implants have fulfilled all the criteria of implant success and based on the defined criteria, the success rate of implants placed in immediate extraction sockets of anterior teeth compared favorably with the conventional implants. The early results of the present study showed that high survival rates with the implants in immediate extraction sockets can be achieved. PMID:26266220

  7. Survival of Implants in Immediate Extraction Sockets of Anterior Teeth: Early Clinical Results.

    PubMed

    Sabir, Mohammad; Alam, Mohammad Nazish

    2015-06-01

    The aims and objectives of this study were placement of implants in freshly extracted sockets of anterior teeth and to evaluate the implant stability, peri-implant radiolucency and gingival inflammation around implant over a short period of 30 months. A total of 12 patients (8 male and 4 female), ranging in the age from 20 to 50 years, from March 2007 to June 2007, were evaluated for immediate implant placement into 22 fresh extraction sockets. Only maxillary and mandibular anterior teeth/roots (central incisors, lateral incisors and canines) were considered for replacement with implants. One piece implant with integrated abutment and integrated surface, non-submerged, threaded and tapered at apical 5 mm, sand-blasted and acid etched surfaced implants (HI-TEC TRX-OP Implants of Life Care Company) were used. The mobility was not present in any of the implants at all the follow up visits. There were 2 implants at 6 month, 1 implant at 12 month, 1 implant at 18 month visits, showing peri-implant radiolucency at some sites at bone to implant contact site. Severe gingival inflammation was not observed in any of the implant site. At every follow-up visit, every implant met the criteria of success and none was found to be failed over a 30 months duration i.e. 100% success rate was achieved by implants in immediate extraction socket. The success rate of implant survival in this study was found 100%. These implants have fulfilled all the criteria of implant success and based on the defined criteria, the success rate of implants placed in immediate extraction sockets of anterior teeth compared favorably with the conventional implants. The early results of the present study showed that high survival rates with the implants in immediate extraction sockets can be achieved.

  8. Biomechanical behaviour of a jawbone loaded with a prosthetic system supported by monophasic and biphasic implants.

    PubMed

    Inchingolo, F; Paracchini, L; DE Angelis, F; Cielo, A; Orefici, A; Spitaleri, D; Santacroce, L; Gheno, E; Palermo, A

    2016-01-01

    Modern implantology is based on the use of endosseous dental implants and on the study of osseointegration processes. The loss of marginal bone around a dental implant can be caused by many factors; the proper distribution of the masticatory loads is important and is closely dependent on the quality and quantity of bone tissue surrounding the implant. In fact, bone has the ability to adapt its microstructure, through processes of resorption and neoformation of new bone matrix, as a result of the mechanical stimuli that are generated during the chewing cycles. The purpose of this article is to redefine in a modern key and in light of current industrial and engineering technology, clinical and biomechanical concepts that characterize the monophasic implants, in order to assess proper use by evaluating the biomechanical differences with the biphasic implants.

  9. Sensitivity and Specificity of Stability Criteria for Immediately Loaded Splinted Maxillary Implants.

    PubMed

    Wentaschek, Stefan; Scheller, Herbert; Schmidtmann, Irene; Hartmann, Sinsa; Weyhrauch, Michael; Weibrich, Gernot; Lehmann, Karl Martin

    2015-10-01

    To assess the suitability of dental implants for immediate loading, primary stability is usually evaluated intraoperatively. This retrospective study aimed to assess the suitability of three stability parameters - namely, insertion torque (IT), implant stability quotient (ISQ; measured by resonance frequency analysis), and Periotest (PT) values - as potential predictors for the risk of nonosseointegration of immediately loaded splinted implants. The stability parameters were routinely collected under immediate loading. Nineteen patients with 11 edentulous and 8 partially edentulous maxillae were treated with 105 dental implants, which were immediately loaded using temporary fixed dentures. The IT results, PT values, and ISQ results were recorded. Receiver operating characteristic analysis was performed to assess the quality of each parameter as a diagnostic test. After a 3-month observation period, 11 implants in four patients were not osseointegrated. The IT and ISQ (IT 25.0 ± 12.5 Ncm and 8.4 ± 2.3 Ncm; PT -1.5 ± 3.0 and +2.7 ± 3.0; and ISQ 62.6 ± 6.7 and 54.7 ± 6.2) differed significantly between the osseointegrated and failed implants (p < .005). The IT showed the greatest specificity at a sensitivity of 1 and the greatest area under the curve (AUC; 0.929), followed by the PT value (AUC = 0.836) and ISQ (AUC = 0.811). Among the intraoperative parameters analyzed, IT showed the highest specificity at a high sensitivity of 1. Therefore, the IT can be considered the most valid prognostic factor for osseointegration of immediately loaded splinted dental implants. © 2014 Wiley Periodicals, Inc.

  10. Peak insertion torque values of five mini-implant systems under different insertion loads.

    PubMed

    Quraishi, Erma; Sherriff, Martyn; Bister, Dirk

    2014-06-01

    To assess the effect of 1 and 3 kg insertion load on five makes of self-drilling mini-implants on peak insertion torque values to establish risk factors involved in the fracture of mini-implants. Two different loads were applied during insertion of 40 mini-implants from five different manufacturers (Dual Top(™) (1·6×8 mm), Infinitas(™) (1·5×9 mm), Ortho Easy(™) (1·7×8 mm), Spider Screw(™) (1·5×8 mm) and Vector TAS(™) (1·4×8 mm)) into acrylic blocks at 8 rev/min utilizing a Motorized Torque Measurement Stand. Peak insertion torque values for both loads were highest for Vector TAS followed by Ortho Easy and Dual Top and were nearly three times higher than Infinitas (original version) and Spider Screws(TM). The log-rank test showed statistically significant differences for both loads for Vector TAS, Ortho Easy and Spider Screws. Unlike other designs tested, both tapered mini-implant designs (Spider Screw and Infinitas) showed a tendency to buckle in the middle of the body but fractured at the tip. Non-tapered mini-implants fractured at significantly higher torque values compared to tapered designs under both loads. Increased pressure resulted in slightly higher maximum torque values at fracture for some of the mini-implant designs, although this is unlikely to be of clinical relevance. Tripling insertion pressure from 1 to 3 kg increased the risk of bending tapered mini-implants before fracture. © 2014 British Orthodontic Society.

  11. In-vitro development of a temporal abutment screw to protect osseointegration in immediate loaded implants.

    PubMed

    García-Roncero, Herminio; Caballé-Serrano, Jordi; Cano-Batalla, Jordi; Cabratosa-Termes, Josep; Figueras-Álvarez, Oscar

    2015-04-01

    In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous®; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at 30° in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%. Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes. Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants.

  12. In-vitro development of a temporal abutment screw to protect osseointegration in immediate loaded implants

    PubMed Central

    2015-01-01

    PURPOSE In this study, a temporal abutment fixation screw, designed to fracture in a controlled way upon application of an occlusal force sufficient to produce critical micromotion was developed. The purpose of the screw was to protect the osseointegration of immediate loaded single implants. MATERIALS AND METHODS Seven different screw prototypes were examined by fixing titanium abutments to 112 Mozo-Grau external hexagon implants (MG Osseous®; Mozo-Grau, S.A., Valladolid, Spain). Fracture strength was tested at 30° in two subgroups per screw: one under dynamic loading and the other without prior dynamic loading. Dynamic loading was performed in a single-axis chewing simulator using 150,000 load cycles at 50 N. After normal distribution of obtained data was verified by Kolmogorov-Smirnov test, fracture resistance between samples submitted and not submitted to dynamic loading was compared by the use of Student's t-test. Comparison of fracture resistance among different screw designs was performed by the use of one-way analysis of variance. Confidence interval was set at 95%. RESULTS Fractures occurred in all screws, allowing easy retrieval. Screw Prototypes 2, 5 and 6 failed during dynamic loading and exhibited statistically significant differences from the other prototypes. CONCLUSION Prototypes 2, 5 and 6 may offer a useful protective mechanism during occlusal overload in immediate loaded implants. PMID:25932315

  13. Influence of matrix attachment installation load on movement and resultant forces in implant overdentures.

    PubMed

    Goto, Takaharu; Nagao, Kan; Ishida, Yuichi; Tomotake, Yoritoki; Ichikawa, Tetsuo

    2015-02-01

    This in vitro study investigated the effect of attachment installation conditions on the load transfer and denture movements of implant overdentures, and aims to clarify the differences among the three types of attachments, namely ball, Locator, and magnet attachments. Three types of attachments, namely ball, Locator, and magnetic attachments were used. An acrylic resin mandibular edentulous model with two implants placed in the bilateral canine regions and removable overdenture were prepared. The two implants and bilateral molar ridges were connected to three-axis load-cell transducers, and a universal testing machine was used to apply a 50 N vertical force to each site of the occlusal table in the first molar region. The denture movement was measured using a G(2) motion sensor. Three installation conditions, namely, the application of 0, 50, and 100 N loads were used to install each attachment on the denture base. The load transfer and denture movement were then evaluated. The resultant force decreased with increasing installation load for all attachments. In particular, the resultant force on implants on the loading side of the Locator attachment significantly decreased when the installation load was increased from 0 to 50 N, and that for magnetic attachment significantly decreased when the installation load was increased from 50 to 100 N. For the residual ridges on the loading side, the direction of the forces for all attachments changed to downward with increasing installation load. Furthermore, the yaw Euler angle increased with increasing installation load for the magnetic attachment. Subject to the limitations of this study, the use of any installation load greater than 0 N is recommended for the installation of ball and Locator attachments on a denture base. Regarding magnetic attachments, our results also recommend installation on a denture base using any installation load greater than 0 N, and suggest that the resultant force acting on the implant can be

  14. Social conversational skills development in early implanted children.

    PubMed

    Guerzoni, Letizia; Murri, Alessandra; Fabrizi, Enrico; Nicastri, Maria; Mancini, Patrizia; Cuda, Domenico

    2016-09-01

    Social conversational skills are a salient aspect of early pragmatic development in young children. These skills include two different abilities, assertiveness and responsiveness. This study investigated the development of these abilities in early implanted children and their relationships with lexical development and some language-sensitive variables. Prospective, observational, nonrandomized study. Participants included 28 children with congenital profound sensorineural hearing loss. The mean age at device activation was 13.3 months (standard deviation [SD] ±4.2). The Social-Conversational Skills Rating Scale was used to evaluate assertiveness and responsiveness. The MacArthur-Bates Communicative Development Inventory (Words and Sentences form) was used to analyze the lexical development. The device experience was 12 months for each child, and the mean age at testing was 25.9 months (SD ±4.6). Assertiveness and responsiveness scores were within the normal range of normal-hearing age-matched peers. Age at cochlear implant activation exerted a significant impact, with the highest scores associated to the youngest patients. The residual correlations between assertiveness and responsiveness with the lexical development were positive and strongly significant (r = 0.69 and 0.73, respectively). Preoperative hearing threshold demonstrated an associated significant coefficient on the assertiveness score. Age at diagnosis and maternal education level were not correlated with the social conversational skills. Early-implanted children developed social conversational skills that are similar to normal-hearing peers matched for age 1 year after device activation. Social conversational skills and lexical development were strongly correlated, but the present study design cannot specify the direction of this relationship. Children with better preoperative residual hearing exhibited better assertive ability. 4 Laryngoscope, 126:2098-2105, 2016. © 2015 The American Laryngological

  15. Revival of pure titanium for dynamically loaded porous implants using additive manufacturing.

    PubMed

    Wauthle, Ruben; Ahmadi, Seyed Mohammad; Amin Yavari, Saber; Mulier, Michiel; Zadpoor, Amir Abbas; Weinans, Harrie; Van Humbeeck, Jan; Kruth, Jean-Pierre; Schrooten, Jan

    2015-09-01

    Additive manufacturing techniques are getting more and more established as reliable methods for producing porous metal implants thanks to the almost full geometrical and mechanical control of the designed porous biomaterial. Today, Ti6Al4V ELI is still the most widely used material for porous implants, and none or little interest goes to pure titanium for use in orthopedic or load-bearing implants. Given the special mechanical behavior of cellular structures and the material properties inherent to the additive manufacturing of metals, the aim of this study is to investigate the properties of selective laser melted pure unalloyed titanium porous structures. Therefore, the static and dynamic compressive properties of pure titanium structures are determined and compared to previously reported results for identical structures made from Ti6Al4V ELI and tantalum. The results show that porous Ti6Al4V ELI still remains the strongest material for statically loaded applications, whereas pure titanium has a mechanical behavior similar to tantalum and is the material of choice for cyclically loaded porous implants. These findings are considered to be important for future implant developments since it announces a potential revival of the use of pure titanium for additively manufactured porous implants. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Surgical Treatment of Implants Affected by Periimplantitis After 15 Years of Loading: A Case Report.

    PubMed

    Nícoli, Lélis Gustavo; Pigossi, Suzane Cristina; Marcantonio, Cláudio; Leal Zandim-Barcelos, Daniela; Marcantonio, Elcio

    2016-04-01

    The aim of this case report is to describe the surgical treatment of 2 implants affected by periimplantitis after 15 years of loading. The treatment included mechanical and chemical decontamination with topical application of tetracycline associated with a regenerative approach. Both defects were filled with particulate autogenous bone from tuber and covered with resorbable collagen membrane. The follow-up of 30 and 13 months of the implants 24 and 14, respectively, showed an absence of clinical signs of periimplant inflammation and near-complete bone regeneration. The therapy approach was effective in eliminating periimplant inflammation and promoting bone gain around the implants.

  17. Gene expression of inflammation and bone healing in peri-implant crevicular fluid after placement and loading of dental implants. A kinetic clinical pilot study using quantitative real-time PCR.

    PubMed

    Slotte, Christer; Lennerås, Maria; Göthberg, Catharina; Suska, Felicia; Zoric, Neven; Thomsen, Peter; Nannmark, Ulf

    2012-10-01

    Early detection of healing complications after placement of dental implants is a pressing but elusive goal. This paper proposes a non-invasive diagnostic tool for monitoring healing- and peri-implant disease specific genes, complementary to clinical evaluations. Eighteen partially edentulous patients were recruited to this pilot study. Three Brånemark TiUnite® implants/patient (Nobel Biocare) were placed in a one-stage procedure. Abutments with smooth or rough (TiUnite®) surface were placed. The test group (n = 9) received fixed bridges (immediate loading), whereas the control group (n = 9) implants were loaded 3 months after surgery. In addition to clinical measurements, crevicular fluid was collected using paper strips at the implant abutments 2, 14, 28, and 90 days postoperative. mRNA was extracted, purified, and converted to cDNA. Quantitative PCR assays for IL-1β, TNF-α, Osteocalcin (OC), Alkaline Phosphatase (ALP), Cathepsin K, Tartrate Resistant Acid Phosphatase, and 18S ribosomal RNA were designed and validated. Relative gene expression levels were calculated. One implant was lost in the control group and three in the test group. In one test patient, one implant showed lowered stability after 2 to 4 weeks and was unloaded. Later implant stability improved which allowed for loading after 3 to 4 months. TNF-α and ALP most commonly showed correlation with clinical parameters followed by IL-1β and OC. The strongest correlation was found for TNF-α with clinical complications at 2 and 14 days (p = .01/r = -048, and p = .0004/r = -0.56, respectively; test and control groups together). In some cases, gene expression predicted clinical complications (TNF-α, ALP, CK). This study is based on samples from few individuals; still, some genes showed correlation with clinical findings. Further studies are needed to refine and optimize the sampling process, to find the appropriate panel, and to validate gene expression for monitoring implant healing. © 2010 Wiley

  18. Risk factors associated with early implant failure: A 5-year retrospective clinical study.

    PubMed

    Olmedo-Gaya, Maris Victoria; Manzano-Moreno, Francisco J; Cañaveral-Cavero, Esther; de Dios Luna-del Castillo, Juan; Vallecillo-Capilla, Manuel

    2016-02-01

    The replacement of lost teeth with dental implants is a widespread treatment whose associated problems are also frequently encountered. Nevertheless, the factors associated with early implant failure have not been well documented. Further analyses of the factors influencing osseointegration establishment are required to maximize the predictability of the procedure and minimize implant failures. The purpose of this retrospective clinical study was to explore the association between possible risk factors and early implant failure. This retrospective clinical study evaluated 142 participants who received 276 external connection BTI implants between 2007 and 2011. Participant variables (age, sex, systemic disease, tobacco use, alcohol consumption, bruxism, and degree of periodontal disease), implant variables (type of edentulism, localization, area, diameter, length, and bone quality), intervention variables (expansion mechanisms, sinus augmentation techniques, bone regeneration, and implant insertion), and postoperative variables (presence of pain/inflammation at 1 week postsurgery) were studied. A multilevel logistic regression model (mixed effects-type model) was used to determine the influence of variables on early implant failure. Early implant failure was significantly associated with the male sex (P=.001), severe periodontal disease (P=.005), short implants (P=.001), expansion technique (P=.002), and postoperative pain/inflammation at 1 week postsurgery (P<.001). Early dental implant failure is more frequent in men and in individuals with severe periodontal disease, short implants, pain/inflammation at 1 week postsurgery, or bone expansion treatment. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  19. The mechanical response of a polyetheretherketone femoral knee implant under a deep squatting loading condition.

    PubMed

    de Ruiter, Lennert; Janssen, Dennis; Briscoe, Adam; Verdonschot, Nico

    2017-12-01

    The current study was designed to investigate the mechanical response of a polyetheretherketone-on-polyethylene total knee replacement device during a deep squat. Application of this high-demand loading condition can identify weaknesses of the polyetheretherketone relative to cobalt-chromium. This study investigated whether the implant is strong enough for this type of loading, whether cement stresses are considerably changed and whether a polyetheretherketone femoral component is likely to lead to reduced periprosthetic bone loss as compared to a cobalt-chromium component. A finite element model of a total knee arthroplasty subjected to a deep squat loading condition, which was previously published, was adapted with an alternative total knee arthroplasty design made of either polyetheretherketone or cobalt-chromium. The maximum tensile and compressive stresses within the implant and cement mantle were analysed against their yield and fatigue stress levels. The amount of stress shielding within the bone was compared between the polyetheretherketone and cobalt-chromium cases. Relative to its material strength, tensile peak stresses were higher in the cobalt-chromium implant; compressive peak stresses were higher in the polyetheretherketone implant. The stress patterns differed substantially between polyetheretherketone and cobalt-chromium. The tensile stresses in the cement mantle supporting the polyetheretherketone implant were up to 33% lower than with the cobalt-chromium component, but twice as high for compression. Stress shielding was reduced to a median of 1% for the polyetheretherketone implant versus 56% for the cobalt-chromium implant. Both the polyetheretherketone implant and the underlying cement mantle should be able to cope with the stress levels present during a deep squat. Relative to the cobalt-chromium component, stress shielding of the periprosthetic femur was substantially less with a polyetheretherketone femoral component.

  20. Stability Development of Immediately Loaded Hybrid Self-Tapping Implants Inserted in the Posterior Maxilla: 1-Year Results of a Randomized Controlled Trial.

    PubMed

    Todorovic, Vladimir S; Vasovic, Miroslav; Beetge, Mia-Michaela; van Zyl, Andre W; Kokovic, Vladimir

    2017-02-01

    The objective of the present study was to elucidate stability development of immediately loaded hybrid self-tapping implants inserted in the posterior maxilla. Forty-eight hybrid self-tapping implants with a chemically modified surface (∅4.1; length: 8 mm) were inserted bilaterally in the maxillary first and second premolar and first molar sites of 8 patients. In each patient, both sides of the maxilla were assigned randomly to either immediate (IL) or early (EL) loading group. Implant stability was evaluated by means of resonance frequency analysis immediately after implant placement and after 1, 2, 3, 4, 5, 6, 12, 26, and 52 weeks. High values of primary stability were found in both groups (71.91 ± 6.52 implant stability quotient [ISQ] in IL group; 73.87 ± 6.5 ISQ in EL group), with significant differences between the groups at the different time points. Initial decrease in stability was observed between the first and fifth weeks in the IL group and between the first and third weeks for the EL group. In the IL group 1 implant was removed after 3 weeks due to lack of stability. Early results of this study showed the ability of hybrid self-tapping dental implants with a chemically modified surface to achieve sufficient primary stability and to maintain high values of secondary implant stability in bone type 3 and 4, even when loaded immediately. Minimal alterations in stability were observed for both investigated groups, but the EL group showed faster recovery after an initial drop in stability.

  1. Simulation of the mechanical behavior of a HIP implant. Implant fixed to bone by cementation under arbitrary load

    NASA Astrophysics Data System (ADS)

    Oldani, C. R.; Dominguez, A. A.

    2007-11-01

    In a previous work a finite elements model was constructed to simulate a fatigue assay according to the norm IRAM 9422-3. Three materials were studied, two of them are the most used in this type of implant (Stainless steel 3161 and alloy T16A14V) and the third was a new developed titanium alloy (Ti35Nb7Zr5Ta). Static loads were applied to the model according to the highest requirements of the norm and the stress - strain distribution were determined. In this study a simplified analysis of the material's fatigue was done according to the previous work. The best behavior of the titanium alloys vs. the stainless steel was evident. With the objective of studying the behavior of both: the implant and the femur bone, new finite elements models were realized, in which the presence of the bone was considered. Inside the bone, the femoral component of the implant was placed in a similar way of a cemented prosthesis in a total hip arthroplasty. The advantage of the titanium implant related to the stainless steel one, was very clear.

  2. Influence of the implant abutment types and the dynamic loading on initial screw loosening

    PubMed Central

    Kim, Eun-Sook

    2013-01-01

    PURPOSE This study examined the effects of the abutment types and dynamic loading on the stability of implant prostheses with three types of implant abutments prepared using different fabrication methods by measuring removal torque both before and after dynamic loading. MATERIALS AND METHODS Three groups of abutments were produced using different types of fabrication methods; stock abutment, gold cast abutment, and CAD/CAM custom abutment. A customized jig was fabricated to apply the load at 30° to the long axis. The implant fixtures were fixed to the jig, and connected to the abutments with a 30 Ncm tightening torque. A sine curved dynamic load was applied for 105 cycles between 25 and 250 N at 14 Hz. Removal torque before loading and after loading were evaluated. The SPSS was used for statistical analysis of the results. A Kruskal-Wallis test was performed to compare screw loosening between the abutment systems. A Wilcoxon signed-rank test was performed to compare screw loosening between before and after loading in each group (α=0.05). RESULTS Removal torque value before loading and after loading was the highest in stock abutment, which was then followed by gold cast abutment and CAD/CAM custom abutment, but there were no significant differences. CONCLUSION The abutment types did not have a significant influence on short term screw loosening. On the other hand, after 105 cycles dynamic loading, CAD/CAM custom abutment affected the initial screw loosening, but stock abutment and gold cast abutment did not. PMID:23509006

  3. Porous, Dexamethasone-loaded polyurethane coatings extend performance window of implantable glucose sensors in vivo.

    PubMed

    Vallejo-Heligon, Suzana G; Brown, Nga L; Reichert, William M; Klitzman, Bruce

    2016-01-01

    Continuous glucose sensors offer the promise of tight glycemic control for insulin dependent diabetics; however, utilization of such systems has been hindered by issues of tissue compatibility. Here we report on the in vivo performance of implanted glucose sensors coated with Dexamethasone-loaded (Dex-loaded) porous coatings employed to mediate the tissue-sensor interface. Two animal studies were conducted to (1) characterize the tissue modifying effects of the porous Dex-loaded coatings deployed on sensor surrogate implants and (2) investigate the effects of the same coatings on the in vivo performance of Medtronic MiniMed SOF-SENSOR™ glucose sensors. The tissue response to implants was evaluated by quantifying macrophage infiltration, blood vessel formation, and collagen density around implants. Sensor function was assessed by measuring changes in sensor sensitivity and time lag, calculating the Mean Absolute Relative Difference (MARD) for each sensor treatment, and performing functional glucose challenge test at relevant time points. Implants treated with porous Dex-loaded coatings diminished inflammation and enhanced vascularization of the tissue surrounding the implants. Functional sensors with Dex-loaded porous coatings showed enhanced sensor sensitivity over a 21-day period when compared to controls. Enhanced sensor sensitivity was accompanied with an increase in sensor signal lag and MARD score. These results indicate that Dex-loaded porous coatings were able to elicit an attenuated tissue response, and that such tissue microenvironment could be conducive towards extending the performance window of glucose sensors in vivo. In the present article, a coating to extend the functionality of implantable glucose sensors in vivo was developed. Our study showed that the delivery of an anti-inflammatory agent with the presentation of micro-sized topographical cues from coatings may lead to improved long-term glucose sensor function in vivo. We believe that

  4. Early Vocabulary Development in Children with Bilateral Cochlear Implants

    ERIC Educational Resources Information Center

    Välimaa, Taina; Kunnari, Sari; Laukkanen-Nevala, Päivi; Lonka, Eila

    2018-01-01

    Background: Children with unilateral cochlear implants (CIs) may have delayed vocabulary development for an extended period after implantation. Bilateral cochlear implantation is reported to be associated with improved sound localization and enhanced speech perception in noise. This study proposed that bilateral implantation might also promote…

  5. Effects of lateral cortical anchorage on the primary stability of implants subjected to controlled loads: an in vitro study.

    PubMed

    Xiao, Jian-rui; Li, Yong-Qi; Guan, Su-Min; Kong, Liang; Liu, Baolin; Li, Dehua

    2012-03-01

    Our aim was to evaluate the effects of lateral cortical anchorage on the primary stability of implants subjected to immediate loading. Implants were placed into bovine bones with monocortical anchorage (implant placed through the cortical bone of the crest) and bicortical anchorage (the crest cortical bone plus one cortical bone on the lateral side). Loads of 25N and 50N were applied to the implants in different cycles. The implant stability quotient (ISQ) was measured before and after the cyclic loadings. Under 25N load there was no difference in ISQ between 1800 cyclic loading and preloading, but the values decreased significantly after 3600 cyclic loading in both groups (p<0.05). Under a 50N load the ISQ value after 1800 and 3600 cyclic loading decreased in the monocortical group (p<0.05), but there was no difference between 1800 cyclic loading and preloading in the bicortical group, and the ISQ in the bicortical group was higher than in the monocortical group after 1800 cyclic loading (p<0.05). Our results suggest that the stability of implants with bicortical anchorage decreased more slowly under higher loads. Copyright © 2011 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

  6. No influence of simultaneous bone-substitute application on the success of immediately loaded dental implants: a retrospective cohort study.

    PubMed

    Kopp, Sigmar; Behrend, Detlef; Kundt, Günther; Ottl, Peter; Frerich, Bernhard; Warkentin, Mareike

    2013-06-01

    To examine the influence of bone-substitute application during implantation on the success of immediately placed and loaded dental implants. A total of 147 consecutive patients (age, 16.5-80.4 years) were provided with 696 immediately loaded implants. The mean follow-up time was 34.1 months. Of these implants, 50.4% (n=351) were immediately placed into extraction sockets. A total of 119 implants were added by simultaneous bone-substitute application (NanoBone, Artoss GmbH, Rostock Germany), whereas the other implants were placed in healed bone. Univariate and multivariate analysis was performed using IBM SPSS V.20. The overall implant success rate was 96.1%. Implants with simultaneous bone replacement had a hazard ratio of 0.877 (p=0.837); 95% CI, 0.253-3.04). Factors found to be statistically significant modifiers of success on multivariate analysis (p<0.05) included type of superstructure (p<0.001), implant-abutment connection (p<0.001), membrane use (p=0.010), and jaw (p=0.026). None of the other factors investigated were significant modifiers. The present study demonstrates high success rates for immediately loaded implants and their superstructures independent of the simultaneous application of bone substitute. The declared aim of socket preservation, the prevention avoiding bone loss, is achieved in the immediate implant placement scenario under immediate-loading conditions.

  7. Phelligridin D-loaded oral nanotube titanium implant enhances osseointegration and prevents osteolysis in rat mandible.

    PubMed

    Kim, Ji-Eun; Takanche, Jyoti Shrestha; Kim, Jeong-Seok; Lee, Min-Ho; Jeon, Jae-Gyu; Park, Il-Song; Yi, Ho-Keun

    2018-04-12

    Poor bone quality and osteolysis are the major causes of implant failure in dentistry. Here, this study tested the effect of phelligridin D-loaded nanotubes titanium (Ti) for bone formation around the dental implants. The purpose of this study was to enhance osseointegration of phelligridin D-loaded implant into the bone for bone formation and prevention of osteolysis. Cell viability, crystal violet staining, Western blot, alizarin red S staining, alkaline phosphatase activity, tartrate-resistant acid phosphatase staining, micro-computed tromography (μ-CT), hematoxylin and eosin (H&E) and immunohistochemical staining were used in vitro and in vivo to test the biocompatibility of phelligridin D. Phelligridin D enhanced osteoblast differentiation and mineralization by increasing bone morphogenic protein-2/7 (BMP-2/7), Osterix, Runx-2, osteoprotegerin (OPG), alkaline phosphatase and inhibited osteoclast differentiation by decreasing receptor activator of nuclear factor kappa-B ligand (RANKL) in MC-3T3 E1 cells. Further, phelligridin D promoted bone regeneration around nanotube Ti implant surface by increasing the levels of BMP-2/7 and OPG in a rat model. Phelligridin D also inhibited osteolysis by suppressing the expression of RANKL. These findings strongly suggest that phelligridin D is a new compound representing a potential therapeutic candidate for implant failure caused by osteolysis and poor bone quality of teeth.

  8. Micromotion and stress distribution of immediate loaded implants: a finite element analysis.

    PubMed

    Fazel, A; Aalai, S; Rismanchian, M; Sadr-Eshkevari, P

    2009-12-01

    Primary stability and micromotion of the implant fixture is mostly influenced by its macrodesign. To assess and compare the peri-implant stress distribution and micromotion of two types of immediate loading implants, immediate loaded screw (ILS) Nisastan and Xive (DENTSPLY/Friadent, Monnheim, Germany), and to determine the best macrodesign of these two implants by finite element analysis. In this experimental study, the accurate pictures of two fixtures (ILS: height = 13, diameter = 4 mm and Xive: height = 13, diameter = 3.8 mm) were taken by a new digital camera (Nikon Coolpix 5700 [Nikon, Japan], resolution = 5.24 megapixel, lens = 8x optical, 4x digital zoom). Following accurate measurements, the three-dimensional finite element computer model was simulated and inserted in simulated mandibular bone (D(2)) in SolidWorks 2003 (SolidWork Corp., MA, USA) and Ansys 7.1 (Ansys, Inc., Canonsburg, PA, USA). After loading (500 N, 75 degrees above horizon), the displacement was displayed and von Mises stress was recorded. It was found that the primary stability of ILS was greater (152 microm) than Xive (284 microm). ILS exhibited more favorable stress distribution. Maximum stress concentration found in periapical bone around Xive ( approximately 30 MPa) was lesser than Nisastan ( approximately 37 MPa). Macrodesign of ILS leads to better primary stability and stress distribution. Maximum stress around Xive was less.

  9. Dopamine-assisted fixation of drug-loaded polymeric multilayers to osteoarticular implants for tuberculosis therapy.

    PubMed

    Li, Dan; Li, Litao; Ma, Yunlong; Zhuang, Yaping; Li, Dawei; Shen, Hong; Wang, Xing; Yang, Fei; Ma, Yuanzheng; Wu, Decheng

    2017-03-28

    Currently, the major issues in the treatment of osteoarticular tuberculosis (TB) after implant placement are low drug concentration at the infected focus and drug resistance resulting from the long-term chemotherapy. The application of drug-loaded polymeric multilayers on implantable devices offers a promising solution to the problems. Herein, a poly(ethylene glycol)-based hydrogel film embedded with isoniazid (INH)-loaded alginate microparticles was fixed to Ti implants via adhesive polydopamine, subsequently capped by poly(lactic-co-glycolic acid) membranes for the sustained and localized delivery of the anti-TB drug. The antibacterial efficacy of the released INH was confirmed by a 4.5 ± 0.8 cm inhibition zone formed in the fourth week after inoculation of Mycobacterium tuberculosis. The INH-loaded Ti implants showed no toxicity to the osteoblast cell and provided a consistent drug release for nearly one week in vitro. The release profile in vivo showed a high local concentration and low systemic exposure. The local INH concentration could be kept higher than its minimum inhibitory concentration over a period of 8 weeks, which proves that it is a promising strategy to improve the severe osteoarticular TB treatment.

  10. In vivo tissue distribution and efficacy studies for cyclosporin A loaded nano-decorated subconjunctival implants.

    PubMed

    Yavuz, Burçin; Bozdağ Pehlivan, Sibel; Kaffashi, Abbas; Çalamak, Semih; Ulubayram, Kezban; Palaska, Erhan; Çakmak, Hasan Basri; Ünlü, Nurşen

    2016-11-01

    Biodegradable implants are promising drug delivery systems for sustained release ocular drug delivery with the benefits such as minimum systemic side effects, constant drug concentration at the target site and getting cleared without surgical removal. Dry eye syndrome (DES) is a common disease characterized with the changes in ocular epithelia surface and results in inflammatory reaction that might lead to blindness. Cyclosporin A (CsA) is a cyclic peptide that is frequently employed for the treatment of DES and it needs to be applied several times a day in tear drops form. The aim of this study was to evaluate in vivo behavior and efficacy of the developed nano-decorated subconjunctival implant systems for sustained release CsA delivery. Biodegradable Poly-ɛ-caprolactone (PCL) implant or micro-fiber implants containing CsA loaded poly-lactide-co-glycolide (85:15) (PLGA) or PCL nanoparticles were prepared in order to achieve sustained release. Two of the formulations PCL-PLGA-NP-F and PCL-PCL-NP-I were selected for in vivo evaluation based on their in vitro characteristics determined in our previous study. In this study, formulations were implanted to Swiss Albino mice with induced dry eye syndrome to investigate the ocular distribution of CsA following subconjunctival implantation and to evaluate the efficacy. Tissue distribution study indicated that CsA was present in ocular tissues such as cornea, sclera and lens even 90 days after the application and blood CsA levels were found lower than ocular tissues. Efficacy studies also showed that application of CsA-loaded fiber implant formulation resulted in faster recovery based on their staining scores.

  11. Early fluid loading for septic patients: Any safety limit needed?

    PubMed

    Gong, Yi-Chun; Liu, Jing-Tao; Ma, Peng-Lin

    2018-02-01

    Early adequate fluid loading was the corner stone of hemodynamic optimization for sepsis and septic shock. Meanwhile, recent recommended protocol for fluid resuscitation was increasingly debated on hemodynamic stability vs risk of overloading. In recent publications, it was found that a priority was often given to hemodynamic stability rather than organ function alternation in the early fluid resuscitation of sepsis. However, no safety limits were used at all in most of these reports. In this article, the rationality and safety of early aggressive fluid loading for septic patients were discussed. It was concluded that early aggressive fluid loading improved hemodynamics transitorily, but was probably traded off with a follow-up organ function impairment, such as worsening oxygenation by reduction of lung aeration, in a part of septic patients at least. Thus, a safeguard is needed against unnecessary excessive fluids in early aggressive fluid loading for septic patients. Copyright © 2017 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.

  12. Macroscopic and microscopic evaluation of a new implant design supporting immediately loaded full arch rehabilitation

    PubMed Central

    Tetè, Stefano; Zizzari, Vincenzo; De Carlo, Alessandro; Sinjari, Bruna; Gherlone, Enrico

    2012-01-01

    Summary The purpose of this study is to evaluate macroscopic and microscopic appearance of a new implant design, with particular emphasis given to the type of prosthesis connection. Two dental implants of the same type (Torque Type®, WinSix®, BioSAFin. S.r.l. - Ancona, Italy), with sandblasted and acid etched surfaces (Micro Rough Surface®), but differing from each other for the prosthesis connection system, were examined by scanning electron microscope (SEM) analysis at different magnifications: TTI implant, with a hexagonal internal connection, and TTX implant, with a hexagonal external connection. SEM analysis showed that the Torque Type® implant is characterized by a truncated cone shape with tapered tips. The implant body showed a double loop thread and double pitch with blunt tips. For both types of connection, the implant neck was 0.7 mm in height with a 3% taper. This implant design may be able to guarantee osteotomic properties at the time of insertion in a surgical site suitably prepared, a facilitated screwing, thanks to the thread pitch and to the broad and deep draining grooves, thereby ensuring a good primary stability. The different connection design appears defined and precise, in order to ensure a good interface between the fixture and the prosthetic components. Therefore, this design appears to be particularly suitable in cases where a good primary stability is necessary and a precise coupling between endosseous and prosthetic components, as it allows an easy insertion of the fixture even in conditions of reduced bone availability, and in cases of immediately loaded full-arch rehabilitations. PMID:23087785

  13. Macroscopic and microscopic evaluation of a new implant design supporting immediately loaded full arch rehabilitation.

    PubMed

    Tetè, Stefano; Zizzari, Vincenzo; De Carlo, Alessandro; Sinjari, Bruna; Gherlone, Enrico

    2012-04-01

    The purpose of this study is to evaluate macroscopic and microscopic appearance of a new implant design, with particular emphasis given to the type of prosthesis connection. Two dental implants of the same type (Torque Type(®), WinSix(®), BioSAFin. S.r.l. - Ancona, Italy), with sandblasted and acid etched surfaces (Micro Rough Surface(®)), but differing from each other for the prosthesis connection system, were examined by scanning electron microscope (SEM) analysis at different magnifications: TTI implant, with a hexagonal internal connection, and TTX implant, with a hexagonal external connection. SEM analysis showed that the Torque Type(®) implant is characterized by a truncated cone shape with tapered tips. The implant body showed a double loop thread and double pitch with blunt tips. For both types of connection, the implant neck was 0.7 mm in height with a 3% taper. This implant design may be able to guarantee osteotomic properties at the time of insertion in a surgical site suitably prepared, a facilitated screwing, thanks to the thread pitch and to the broad and deep draining grooves, thereby ensuring a good primary stability. The different connection design appears defined and precise, in order to ensure a good interface between the fixture and the prosthetic components. Therefore, this design appears to be particularly suitable in cases where a good primary stability is necessary and a precise coupling between endosseous and prosthetic components, as it allows an easy insertion of the fixture even in conditions of reduced bone availability, and in cases of immediately loaded full-arch rehabilitations.

  14. Misfit of Three Different Implant-Abutment Connections Before and After Cyclic Load Application: An In Vitro Study.

    PubMed

    Gehrke, Sergio Alexandre; Delgado-Ruiz, Rafael Arcesio; Prados Frutos, Juan Carlos; Prados-Privado, María; Dedavid, Berenice Anina; Granero Marín, Jose Manuel; Calvo Guirado, José Luiz

    This study aimed to evaluate the misfit of three different implant-abutment connections before and after cycling load. One hundred twenty dental implants and correspondent prefabricated titanium abutments were used. Three different implant-abutment connections were evaluated: Morse taper (MT group), external hexagon (EH group), and internal hexagon (IH group). Forty implants and 40 abutments were used per group. The parameters for the mechanical evaluation were set as: 360,000 cycles, load of 150 N, and frequency of 4 Hz. Samples were sectioned in their longitudinal and transversal axes, and the misfit of the implant-abutment connection was evaluated by scanning electron microscopy analysis. One-way analyses of variance, Tukey post hoc analyses (α = .05), and t test (P < .05) were used to determine differences between groups. At the longitudinal direction, all the groups showed the presence of microgaps before cycling load; after cycling load, microgaps were reduced in all groups (P > .05). Transversally, only the MT group showed full fitting after cycling load compared with the other groups (EH and IH) (P < .0001). The application of cycling load produces an accommodation of the implant-abutment connection in internal, external, and Morse taper connections. In the longitudinal direction, the accommodation decreases and/or eliminates the gap observed initially (before load). In the horizontal direction, Morse cone implant-abutment connections experience a complete accommodation with the elimination of the gap.

  15. Fracture mode during cyclic loading of implant-supported single-tooth restorations.

    PubMed

    Hosseini, Mandana; Kleven, Erik; Gotfredsen, Klaus

    2012-08-01

    Fracture of veneering ceramics in zirconia-based restorations has frequently been reported. Investigation of the fracture mode of implant-supported ceramic restorations by using clinically relevant laboratory protocols is needed. This study compared the mode of fracture and number of cyclic loads until veneering fracture when ceramic and metal ceramic restorations with different veneering ceramics were supported by implants. Thirty-two implant-supported single-tooth restorations were fabricated. The test group was composed of 16 ceramic restorations of zirconia abutment-retained crowns with zirconia copings veneered with glass-ceramics (n=8) and feldspathic ceramics (n=8). The control group was composed of 16 metal ceramic restorations of titanium abutment-retained crowns with gold alloy copings veneered with glass (n=8) and feldspathic ceramics (n=8). The palatal surfaces of the crowns were exposed to cyclic loading of 800 N with a frequency of 2 Hz, which continued to 4.2 million cycles or until fracture of the copings, abutments, or implants. The number of cycles and the fracture modes were recorded. The fracture modes were analyzed by descriptive analysis and the Mann-Whitney test (α=.05). The differences in loading cycles until veneering fracture were estimated with the Cox proportional hazards analysis. Veneering fracture was the most frequently observed fracture mode. The severity of fractures was significantly more in ceramic restorations than in metal ceramic restorations. Significantly more loading cycles until veneering fracture were estimated with metal ceramic restorations veneered with glass-ceramics than with other restorations. The metal ceramic restorations demonstrated fewer and less severe fractures and resisted more cyclic loads than the ceramic restorations, particularly when the metal ceramic crowns were veneered with glass-ceramics. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All

  16. Subgingival Microbiome Colonization and Cytokine Production during Early Dental Implant Healing.

    PubMed

    Payne, Jeffrey B; Johnson, Paul G; Kok, Car Reen; Gomes-Neto, João C; Ramer-Tait, Amanda E; Schmid, Marian J; Hutkins, Robert W

    2017-01-01

    Little is known about longitudinal development of the peri-implant subgingival microbiome and cytokine production as a new sulcus forms after dental implant placement. Therefore, the purpose of this observational study was to evaluate simultaneous longitudinal changes in the oral microbiome and cytokine production in the developing peri-implant sulcus compared to control natural teeth. Four and 12 weeks after implant placement and abutment connection, a dental implant and a natural tooth were sampled in 25 patients for subgingival plaque and gingival crevicular fluid (GCF [around teeth] and peri-implant crevicular fluid [PICF] around implants). DNA from plaque samples was extracted and sequenced using Illumina-based 16S rRNA sequencing. GCF and PICF samples were analyzed using a customized Milliplex human cytokine and chemokine magnetic bead panel. Beta diversity analysis revealed that natural teeth and implants had similar subgingival microbiomes, while teeth had greater alpha diversity than implants. At the genus level, however, few differences were noted between teeth and dental implants over 12 weeks. Specifically, Actinomyces and Selenomonas were significantly elevated around teeth versus dental implants at both 4 weeks and 12 weeks, while Corynebacterium and Campylobacter were significantly elevated only at 4 weeks around teeth. The only difference between PICF and GCF biomarkers was significantly elevated granulocyte-macrophage colony-stimulating factor levels around teeth versus dental implants at the 4-week visit. The subgingival microbiome and cytokine production were similar between teeth and implants during early healing, suggesting that these profiles are driven by the patient following dental implant placement and are not determined by anatomical niche. IMPORTANCE Dental implants are a common treatment option offered to patients for tooth replacement. However, little is known regarding initial colonization of the subgingival microbiome and

  17. Pain and discomfort following immediate and delayed loading by overdentures in the single mandibular implant study (SMIS).

    PubMed

    Mundt, T; Passia, N; Att, W; Heydecke, G; Freitag-Wolf, S; Luthardt, R G; Kappel, S; Konstantinidis, I K; Stiesch, M; Wolfart, S; Kern, M

    2017-03-01

    This randomized clinical trial compares immediate and delayed loading of single implants to support mandibular overdentures. The aim of this preliminary analysis is to test the hypothesis whether patients with immediate loading will experience less pain and discomfort through the intervention than patients with delayed loading. Edentulous patients in nine German dental schools received a midline implant with a length of 11 mm. Implants with a minimum insertion torque of 30 Ncm and an implant stability quotient of ≥60 were randomly allocated to group A for immediate loading using ball attachments or to group B for delayed loading after 3 months. Patients completed questionnaires with 100-mm visual analogue scales about the items pain, pain during chewing, swelling, bleeding, and perception of the intervention at the day of surgery and 1, 2, 3, and 7 days, thereafter. Groups were compared by Wilcoxon-Mann-Whitney tests (P ≤ 0.05). The questionnaires of 81 patients in group A and 74 patients in group B were completed. The medians for pain and discomfort were moderate (<30). Participants of group A felt significantly more pain from the first day and more swelling from the third day after implantation than participants of group B. The individual perception of interventions showed no significant differences between groups. Immediate loading evoked more postoperative pain and swelling than the two stages of delayed loading. Immediate loading of a single mandibular midline implant supporting overdentures should be carefully considered.

  18. Micromotion-induced strain fields influence early stages of repair at bone-implant interfaces

    PubMed Central

    Wazen, Rima M.; Currey, Jennifer A.; Guo, Hongqiang; Brunski, John B.; Helms, Jill A.; Nanci, Antonio

    2013-01-01

    Implant loading can create micromotion at the bone-implant interface. The interfacial strain associated with implant micromotion could contribute to regulating the tissue healing response. Excessive micromotion can lead to fibrous encapsulation and implant loosening. Our objective was to characterize the influence of interfacial strain on bone regeneration around implants in mouse tibiae. A micromotion system was used to create strain under conditions of (1) no initial contact between implant and bone, and (2) a direct bone-implant contact. Pin- and screw-shaped implants were subjected to displacements of 150 μm or 300 μm, 60 cycles/day, for 7 days. Pin-shaped implants placed in 5 animals were subjected to 3 sessions of 150 μm displacement per day, with 60 cycles per session. Control implants in both types of interfaces were stabilized throughout the healing period. Experimental strain analyses, microtomography, image-based displacement mapping, and finite element simulations were used to characterize interfacial strain fields. Calcified tissue sections were prepared and stained with Goldner to evaluate tissue reaction in higher and lower strain regions. In stable implants, bone formation occurred consistently around the implants. In implants subjected to micromotion, bone regeneration was disrupted in areas of high strain concentrations (e.g. > 30%), whereas lower strain values were permissive of bone formation. Increasing implant displacement or number of cycles per day also changed the strain distribution and disturbed bone healing. These results indicate that not only implant micromotion but also the associated interfacial strain field contributes to regulating the interfacial mechanobiology at healing bone-implant interfaces. PMID:23337705

  19. Fracture resistance of the implant-abutment connection in implants with internal hex and internal conical connections under oblique compressive loading: an in vitro study.

    PubMed

    Coppedê, Abílio Ricciardi; Bersani, Edmilson; de Mattos, Maria da Gloria Chiarello; Rodrigues, Renata Cristina Silveira; Sartori, Ivete Aparecida de Mattias; Ribeiro, Ricardo Faria

    2009-01-01

    The objective of this study was to verify if differences in the design of internal hex (IH) and internal conical (IC) connection implant systems influence fracture resistance under oblique compressive forces. Twenty implant-abutment assemblies were utilized: 10 with IH connections and 10 with IC connections. Maximum deformation force for IC implants (90.58 +/- 6.72 kgf) was statistically higher than that for IH implants (83.73 +/- 4.94 kgf) (P = .0182). Fracture force for the IH implants was 79.86 +/- 4.77 kgf. None of the IC implants fractured. The friction-locking mechanics and the solid design of the IC abutments provided greater resistance to deformation and fracture under oblique compressive loading when compared to the IH abutments.

  20. Dissolution behavior and early bone apposition of calcium phosphate-coated machined implants

    PubMed Central

    Hwang, Ji-Wan; Lee, Eun-Ung; Lee, Jung-Seok; Jung, Ui-Won; Lee, In-Seop

    2013-01-01

    Purpose Calcium phosphate (CaP)-coated implants promote osseointegration and survival rate. The aim of this study was to (1) analyze the dissolution behavior of the residual CaP particles of removed implants and (2) evaluate bone apposition of CaP-coated machined surface implants at the early healing phase. Methods Mandibular premolars were extracted from five dogs. After eight weeks, the implants were placed according to drilling protocols: a nonmobile implant (NI) group and rotational implant (RI) group. For CaP dissolution behavior analysis, 8 implants were removed after 0, 1, 2, and 4 weeks. The surface morphology and deposition of the coatings were observed. For bone apposition analysis, block sections were obtained after 1-, 2-, and 4-week healing periods and the specimens were analyzed. Results Calcium and phosphorus were detected in the implants that were removed immediately after insertion, and the other implants were composed mainly of titanium. There were no notable differences between the NI and RI groups in terms of the healing process. The bone-to-implant contact and bone density in the RI group showed a remarkable increase after 2 weeks of healing. Conclusions It can be speculated that the CaP coating dissolves early in the healing phase and chemically induces early bone formation regardless of the primary stability. PMID:24455442

  1. Fracture load of implant-supported zirconia all-ceramic crowns luted with various cements.

    PubMed

    Lim, Hyun-Pil; Yoo, Jeong-Min; Park, Sang-Won; Yang, Hong-So

    2010-01-01

    This study compared the fracture load and failure types of implant-supported zirconia all-ceramic crowns cemented with various luting agents. The ceramic frameworks were fabricated from a presintered yttria-stabilized zirconium dioxide block using computer-aided design/computer-assisted manufacturing technology, and were then veneered with feldspathic porcelain. Three luting agents were used. Composite resin cement (1,560.78 +/- 39.43 N) showed the highest mean fracture load, followed by acrylic/urethane cement (1,116.20 +/- 77.32 N) and zinc oxide eugenol cement (741.21 +/- 41.95 N) (P < .05). The types of failure varied between groups.

  2. Load to failure of different zirconia implant abutments with titanium components.

    PubMed

    Mascarenhas, Faye; Yilmaz, Burak; McGlumphy, Edwin; Clelland, Nancy; Seidt, Jeremy

    2017-06-01

    Abutments with a zirconia superstructure and a titanium insert have recently become popular. Although they have been tested under static load, their performance under simulated mastication is not well known. The purpose of this in vitro study was to compare the cyclic load to failure of 3 types of zirconia abutments with different mechanisms of retention of the zirconia to the titanium interface. Fifteen implants (n=5 per system) and abutments (3 groups: 5 friction fit [Frft]; 5 bonded; and 5 titanium ring friction fit [Ringfrft]) were used. Abutments were thermocycled in water between 5°C and 55°C for 15000 cycles and then cyclically loaded for 20000 cycles or until failure at a frequency of 2 Hz by using a sequentially increased loading protocol up to a maximum of 720 N. The load to failure for each group was recorded, and 1-way analysis of variance was performed. The mean load-to-failure values for the Frft group was 526 N, for the Bond group 605 N, and for the Ringfrft group 288 N. A statistically significant difference was found among all abutments tested (P<.05). Abutments with the bonded connection showed the highest load-to-failure value, and the abutment with the titanium ring friction fit connection showed the lowest load-to-failure value. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  3. Effects of Food Texture on Three-Dimensional Loads on Implants During Mastication Based on In Vivo Measurements.

    PubMed

    Yoda, Nobuhiro; Ogawa, Toru; Gunji, Yoshinori; Vanegas, Juan R; Kawata, Tetsuo; Sasaki, Keiichi

    2016-08-01

    The mechanisms by which the loads exerted on implants that support prostheses are modulated during mastication remain unclear. The purpose of this study was to evaluate the effects of food texture on 3-dimensional loads measured at a single implant using a piezoelectric transducer. Two subjects participated in this study. The transducer and the experimental superstructure, which had been adjusted to the subject's occlusal scheme, were attached to the implant with a titanium screw. The foods tested were chewing gum and peanuts. The mean maximum load on the implant in each chewing cycle was significantly higher during peanut chewing than during gum chewing. The direction of maximum load was significantly more widely dispersed during peanut chewing than during gum chewing. The range of changes in load direction during the force-increasing phase of each chewing cycle was significantly wider during peanut chewing than during gum chewing. The load on the implant was affected by food texture in both subjects. This measurement method can be useful to investigate the mechanisms of load modulation on implants during mastication.

  4. Comparative histomorphometry and resonance frequency analysis of implants with moderately rough surfaces in a loaded animal model.

    PubMed

    Al-Nawas, B; Groetz, K A; Goetz, H; Duschner, H; Wagner, W

    2008-01-01

    Test of favourable conditions for osseointegration with respect to optimum bone-implant contact (BIC) in a loaded animal model. The varied parameters were surface roughness and surface topography of commercially available dental implants. Thirty-two implants of six types of macro and microstructure were included in the study (total 196). The different types were: minimally rough control: Branemark machined Mk III; oxidized surface: TiUnite MkIII and MkIV; ZL Ticer; blasted and etched surface: Straumann SLA; rough control: titanium plasma sprayed (TPS). Sixteen beagle dogs were implanted with the whole set of the above implants. After a healing period of 8 weeks, implants were loaded for 3 months. For the evaluation of the BIC areas, adequately sectioned biopsies were visualized by subsurface scans with confocal laser scanning microscopy (CLSM). The primary statistical analysis testing BIC of the moderately rough implants (mean 56.1+/-13.0%) vs. the minimally rough and the rough controls (mean 53.9+/-11.2%) does not reveal a significant difference (P=0.57). Mean values of 50-70% BIC were found for all implant types. Moderately rough oxidized implants show a median BIC, which is 8% higher than their minimally rough turned counterpart. The intraindividual difference between the TPS and the blasted and etched counterparts revealed no significant difference. The turned and the oxidized implants show median values of the resonance frequency [implant stability quotients (ISQ)] over 60; the nonself-tapping blasted and etched and TPS implants show median values below 60. In conclusion, the benefit of rough surfaces relative to minimally rough ones in this loaded animal model was confirmed histologically. The comparison of different surface treatment modalities revealed no significant differences between the modern moderately rough surfaces. Resonance frequency analysis seems to be influenced in a major part by the transducer used, thus prohibiting the comparison of

  5. Early speech perception in Mandarin-speaking children at one-year post cochlear implantation.

    PubMed

    Chen, Yuan; Wong, Lena L N; Zhu, Shufeng; Xi, Xin

    2016-01-01

    The aim in this study was to examine early speech perception outcomes in Mandarin-speaking children during the first year of cochlear implant (CI) use. A hierarchical early speech perception battery was administered to 80 children before and 3, 6, and 12 months after implantation. Demographic information was obtained to evaluate its relationship with these outcomes. Regardless of dialect exposure and whether a hearing aid was trialed before implantation, implant recipients were able to attain similar pre-lingual auditory skills after 12 months of CI use. Children speaking Mandarin developed early Mandarin speech perception faster than those with greater exposure to other Chinese dialects. In addition, children with better pre-implant hearing levels and younger age at implantation attained significantly better speech perception scores after 12 months of CI use. Better pre-implant hearing levels and higher maternal education level were also associated with a significantly steeper growth in early speech perception ability. Mandarin-speaking children with CIs are able to attain early speech perception results comparable to those of their English-speaking counterparts. In addition, consistent single language input via CI probably enhances early speech perception development at least during the first-year of CI use. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Bone quality and the immediate loading of implants-critical aspects based on literature, research, and clinical experience.

    PubMed

    Romanos, Georgios E

    2009-06-01

    Immediate loading of oral implants has been extensively described in the international literature and the requirements for long-term success are evaluated. The author presents here the critical aspects of the criteria for success as well as describes the characteristics of an implant macro- and microdesign for immediate loading to control the periimplant crestal bone loss and secure the long-term stability. Information from the literature and the clinical experience will be presented.

  7. Settling of abutments into implants and changes in removal torque in five different implant-abutment connections. Part 1: Cyclic loading.

    PubMed

    Kim, Ki-Seong; Han, Jung-Suk; Lim, Young-Jun

    2014-01-01

    The aim of this study was to evaluate and compare the settling of abutments into implants and the removal torque values (RTVs) before and after cyclic loading. Five different implant-abutment connections were tested: Ext = external butt joint + two-piece abutment; Int-H2 = internal hexagon + two-piece abutment; Int-H1 = internal hexagon + one-piece abutment; Int-O2 = internal octagon + two-piece abutment; and Int-O1 = internal octagon + one-piece abutment. Ten abutments from each group were secured to their corresponding implants (total n = 50). All samples were tested in a universal testing machine with a vertical load of 250 N for 100,000 cycles of 14 Hz. The amount of settling of the abutment into the implant was calculated from the change in the total length of the implant-abutment sample before and after loading, as measured with an electronic digital micrometer. The RTV after cyclic loading was compared to the initial RTV with a digital torque gauge. Statistical analysis was performed at a 5% significance level. A multiple-comparison test showed specific significant differences in settling values in each group after 250 N cyclic loading (Int-H1, Ext < Int-H2 < Int-O2 < Int-O1). There were statistically significant decreases in RTVs after loading compared to the initial RTVs in the Int-H2 and Int-O2 groups. No statistically significant differences were found in the Ext, Int-H1, and Int-O1 groups. The results of this study demonstrated that the settling amount and RTV (loss of preload) after cyclic loading were specific to the abutment type and related to the design characteristics of the implant-abutment connection.

  8. Persistent Language Delay versus Late Language Emergence in Children with Early Cochlear Implantation

    ERIC Educational Resources Information Center

    Geers, Ann E.; Nicholas, Johanna; Tobey, Emily; Davidson, Lisa

    2016-01-01

    Purpose: The purpose of the present investigation is to differentiate children using cochlear implants (CIs) who did or did not achieve age-appropriate language scores by mid-elementary grades and to identify risk factors for persistent language delay following early cochlear implantation. Materials and Method: Children receiving unilateral CIs at…

  9. Changes in Speech Production in an Early Deafened Adult with a Cochlear Implant

    ERIC Educational Resources Information Center

    Wong, Patrick C. M.

    2007-01-01

    Background and Aims: The current study is a first investigation reporting the speech production characteristics of an early deafened adult cochlear implant user after a course of speech-language treatment. Methods and Procedures: The participant is culturally deaf and received the cochlear implant when she was 43 years old. A 24-week ABCABC…

  10. Immediate loading of tapered implants placed in postextraction sockets: retrospective analysis of the 5-year clinical outcome.

    PubMed

    Mura, Priamo

    2012-08-01

    The use of immediate implant loading protocols delivers obvious benefits to the patient. When applied in healed sites, this has not only been well documented in the totally edentolous mandible but has also been documented and reported to be predictable in the upper jaw, and in cases of partial edentoulism, as well. A further application of immediate loading protocol, although still controversial, especially when replacing single maxillary teeth in the anterior zone, is the immediate implant placement and provisionalization in postextractive sockets. In consideration of the oxidized surface promoting bone healing and the tapered shape of the implant body, the Replace Select Tapered TiUnite implants have been used for many years in our clinic when facing these clinical situations. This article will report about our long-term clinical experience with such implants and the relevant role of a correct surgical and prosthetic treatment planning. The aim of this retrospective study was to report on the 5-year clinical and radiologic outcome of patients treated with Replace Select Tapered TiUnite implants when used according to an immediate loading protocol in postextraction sites. In routine practice, 56 consecutive patients were treated with 79 implants. The patients, 23 males and 33 females, had a mean age of 50.9 years, range 21-76 years, at implant placement. Forty-seven implants were placed in the maxilla and 32 implants were placed in the mandible. All implants were placed in postextraction sites and were immediately loaded. Provisional restorations were delivered within 2 hours from surgery and all were in occlusion. Forty-three patients received a single implant while in the remaining 13 patients the implants were splinted. Definitive prosthetic restoration was delivered within 1 to 4 months following implant placement. Evaluations of soft tissue health and marginal bone remodeling were conducted. An independent radiologist performed the radiographic evaluation

  11. Mesoporous TiO2 implants for loading high dosage of antibacterial agent

    NASA Astrophysics Data System (ADS)

    Park, Se Woong; Lee, Donghyun; Choi, Yong Suk; Jeon, Hoon Bong; Lee, Chang-Hoon; Moon, Ji-Hoi; Kwon, Il Keun

    2014-06-01

    We have fabricated mesoporous thin films composed of TiO2 nanoparticles on anodized titanium implant surfaces for loading drugs at high doses. Surface anodization followed by treatment with TiO2 paste leads to the formation of mechanically stable mesoporous thin films with controllable thickness. A series of antibacterial agents (silver nanoparticles, cephalothin, minocycline, and amoxicillin) were loaded into the mesoporous thin films and their antibacterial activities were evaluated against five bacterial species including three oral pathogens. Additionally, two agents (silver nanoparticles and minocycline) were loaded together on the thin film and tested for antibacterial effectiveness. The combination of silver nanoparticles and minocycline was found to display a wide range of effectiveness against all tested bacteria.

  12. Near-infrared fluorescence imaging platform for quantifying in vivo nanoparticle diffusion from drug loaded implants.

    PubMed

    Markovic, Stacey; Belz, Jodi; Kumar, Rajiv; Cormack, Robert A; Sridhar, Srinivas; Niedre, Mark

    2016-01-01

    Drug loaded implants are a new, versatile technology platform to deliver a localized payload of drugs for various disease models. One example is the implantable nanoplatform for chemo-radiation therapy where inert brachytherapy spacers are replaced by spacers doped with nanoparticles (NPs) loaded with chemotherapeutics and placed directly at the disease site for long-term localized drug delivery. However, it is difficult to directly validate and optimize the diffusion of these doped NPs in in vivo systems. To better study this drug release and diffusion, we developed a custom macroscopic fluorescence imaging system to visualize and quantify fluorescent NP diffusion from spacers in vivo. To validate the platform, we studied the release of free fluorophores, and 30 nm and 200 nm NPs conjugated with the same fluorophores as a model drug, in agar gel phantoms in vitro and in mice in vivo. Our data verified that the diffusion volume was NP size-dependent in all cases. Our near-infrared imaging system provides a method by which NP diffusion from implantable nanoplatform for chemo-radiation therapy spacers can be systematically optimized (eg, particle size or charge) thereby improving treatment efficacy of the platform.

  13. The role of single immediate loading implant in long Class IV Kennedy mandibular partial denture.

    PubMed

    Mohamed, Gehan F; El Sawy, Amal A

    2012-10-01

    The treatment of long-span Kennedy class IV considers a prosthodontic challenge. This study evaluated the integrity of principle abutments in long Kennedy class IV clinically and radiographically, when rehabilitated with conventional metallic partial denture as a control group and mandibular partial overdentures supported with single immediately loaded implant in symphyseal as a study group. Twelve male patients were divided randomly allotted into two equal groups. First group patients received removable metallic partial denture, whereas in the second group, patients received partial overdentures supported with single immediately loaded implant in symphyseal region. The partial dentures design in both groups was the same. Long-cone paralleling technique and transmission densitometer were used at the time of denture insertion, 3, 6, and 12 months. Gingival index, bone loss, and optical density were measured for principle abutments during the follow-up. A significant reduction in bone loss and density were detected in group II comparing with group I. Gingival index had no significant change (p-value < 0.05). A single symphyseal implant in long span class IV Kennedy can play a pivotal role to improve the integrity of the principle abutments and alveolar bone support. © 2010 Wiley Periodicals, Inc.

  14. Numerical verification of two-component dental implant in the context of fatigue life for various load cases.

    PubMed

    Szajek, Krzysztof; Wierszycki, Marcin

    2016-01-01

    Dental implant designing is a complex process which considers many limitations both biological and mechanical in nature. In earlier studies, a complete procedure for improvement of two-component dental implant was proposed. However, the optimization tasks carried out required assumption on representative load case, which raised doubts on optimality for the other load cases. This paper deals with verification of the optimal design in context of fatigue life and its main goal is to answer the question if the assumed load scenario (solely horizontal occlusal load) leads to the design which is also "safe" for oblique occlussal loads regardless the angle from an implant axis. The verification is carried out with series of finite element analyses for wide spectrum of physiologically justified loads. The design of experiment methodology with full factorial technique is utilized. All computations are done in Abaqus suite. The maximal Mises stress and normalized effective stress amplitude for various load cases are discussed and compared with the assumed "safe" limit (equivalent of fatigue life for 5e6 cycles). The obtained results proof that coronial-appical load component should be taken into consideration in the two component dental implant when fatigue life is optimized. However, its influence in the analyzed case is small and does not change the fact that the fatigue life improvement is observed for all components within whole range of analyzed loads.

  15. Effect of surface treatment on stress distribution in immediately loaded dental implants--a 3D finite element analysis.

    PubMed

    Bahrami, Babak; Shahrbaf, Shirin; Mirzakouchaki, Behnam; Ghalichi, Farzan; Ashtiani, Mohammed; Martin, Nicolas

    2014-04-01

    To investigate, by means of FE analysis, the effect of surface roughness treatments on the distribution of stresses at the bone-implant interface in immediately loaded mandibular implants. An accurate, high resolution, digital replica model of bone structure (cortical and trabecular components) supporting an implant was created using CT scan data and image processing software (Mimics 13.1; Materialize, Leuven, Belgium). An anatomically accurate 3D model of a mandibular-implant complex was created using a professional 3D-CAD modeller (SolidWorks, DassaultSystèmes Solid Works Corp; 2011). Finite element models were created with one of the four roughness treatments on the implant fixture surface. Of these, three were surface treated to create a uniform coating determined by the coefficient of friction (μ); these were either (1) plasma sprayed or porous-beaded (μ=1.0), (2) sandblasted (μ=0.68) or (3) polished (μ=0.4). The fourth implant had a novel two-part surface roughness consisting of a coronal polished component (μ=0.4) interfacing with the cortical bone, and a body plasma treated surface component (μ=1) interfacing with the trabecular bone. Finite element stress analysis was carried out under vertical and lateral forces. This investigation showed that the type of surface treatment on the implant fixture affects the stress at the bone-implant interface of an immediately loaded implant complex. Von Mises stress data showed that the two-part surface treatment created the better stress distribution at the implant-bone interface. The results from this FE computational analysis suggest that the proposed two-part surface treatment for IL implants creates lower stresses than single uniform treatments at the bone-implant interface, which might decrease peri-implant bone loss. Future investigations should focus on mechanical and clinical validation of these FE results. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  16. Roughness evolution of metallic implant surfaces under contact loading and nanometer-scale chemical etching.

    PubMed

    Ryu, J J; Letchuman, S; Shrotriya, P

    2012-10-01

    Surface damage of metallic implant surface at taper lock and clamped interfaces may take place through synergistic interactions between repeated contact loading and corrosion. In the present research, we investigated the influence of surface roughness and contact loading on the mechanical and chemical damage phenomena. Cobalt-chromium (CoCrMo) specimens with two different roughness configurations created by milling and grinding process were subjected to normal and inclined contact loading. During repeated contact loading, amplitude of surface roughness reached a steady value after decreasing during the first few cycles. During the second phase, the alternating experiment of rough surface contact and micro-etching was conducted to characterize surface evolution behavior. As a result, surface roughness amplitude continuously evolved-decreasing during contact loading due to plastic deformation of contacting asperities and increasing on exposure to corrosive environment by the preferential corrosion attack on stressed area. Two different instabilities could be identified in the surface roughness evolution during etching of contact loaded surfaces: increase in the amplitude of dominant wavenumber and increase in amplitude of a small group of roughness modes. A damage mechanism that incorporates contact-induced residual stress development and stress-assisted dissolution is proposed to elucidate the measured instabilities in surface roughness evolution. Copyright © 2012 Elsevier Ltd. All rights reserved.

  17. Load-Bearing Capacity and Retention of Newly Developed Micro-Locking Implant Prosthetic System: An In Vitro Pilot Study.

    PubMed

    Choi, Jae-Won; Choi, Kyung-Hee; Chae, Hee-Jin; Chae, Sung-Ki; Bae, Eun-Bin; Lee, Jin-Ju; Lee, So-Hyoun; Jeong, Chang-Mo; Huh, Jung-Bo

    2018-04-06

    The aim of this study was to introduce the newly developed micro-locking implant prosthetic system and to evaluate the resulting its characteristics. To evaluate load-bearing capacity, 25 implants were divided into five groups: external-hexagon connection (EH), internal-octagon connection (IO), internal-hexagon connection (IH), one-body implant (OB), micro-locking implant system (ML). The maximum compressive load was measured using a universal testing machine (UTM) according to the ISO 14801. Retention was evaluated in two experiments: (1) a tensile test of the structure modifications of the components (attachment and implant) and (2) a tensile test after cyclic loading (total 5,000,000 cycles, 100 N, 2 Hz). The load-bearing capacity of the ML group was not significantly different from the other groups ( p > 0.05). The number of balls in the attachment and the presence of a hexagonal receptacle did not show a significant correlation with retention ( p > 0.05), but the shape of the retentive groove in the implant post had a statistically significant effect on retention ( p < 0.05). On the other hand, the retention loss was observed during the initial 1,000,000 cycles, but an overall constant retention was maintained afterward. Various preclinical studies on this novel micro-locking implant prosthetic system should continue so that it can be applied in clinical practice.

  18. Load-Bearing Capacity and Retention of Newly Developed Micro-Locking Implant Prosthetic System: An In Vitro Pilot Study

    PubMed Central

    Choi, Kyung-Hee; Chae, Hee-Jin; Chae, Sung-Ki; Bae, Eun-Bin; Lee, Jin-Ju; Lee, So-Hyoun; Jeong, Chang-Mo; Huh, Jung-Bo

    2018-01-01

    The aim of this study was to introduce the newly developed micro-locking implant prosthetic system and to evaluate the resulting its characteristics. To evaluate load-bearing capacity, 25 implants were divided into five groups: external-hexagon connection (EH), internal-octagon connection (IO), internal-hexagon connection (IH), one-body implant (OB), micro-locking implant system (ML). The maximum compressive load was measured using a universal testing machine (UTM) according to the ISO 14801. Retention was evaluated in two experiments: (1) a tensile test of the structure modifications of the components (attachment and implant) and (2) a tensile test after cyclic loading (total 5,000,000 cycles, 100 N, 2 Hz). The load-bearing capacity of the ML group was not significantly different from the other groups (p > 0.05). The number of balls in the attachment and the presence of a hexagonal receptacle did not show a significant correlation with retention (p > 0.05), but the shape of the retentive groove in the implant post had a statistically significant effect on retention (p < 0.05). On the other hand, the retention loss was observed during the initial 1,000,000 cycles, but an overall constant retention was maintained afterward. Various preclinical studies on this novel micro-locking implant prosthetic system should continue so that it can be applied in clinical practice. PMID:29642407

  19. Influence of implant diameter in the displacement of dental implants in trabecular bovine bone under a static lateral load: experimental results and computational modeling.

    PubMed

    Engelke, Wilfried; Decco, Oscar A; Cura, Andrea C; Maldonado, Isai; Crippa, Federico G

    2014-12-01

    Primary stability and micromovement of dental implants depend on structural properties of the surrounding bone and on implant dimension and design. The purpose of this study was to provide objective data for the influence of implant diameter on the displacement of titanium screw implants. Ninety Semados implants (length 15 mm, diameter 3.25, 3.75, and 4.5 mm; Bego, Bremen, Germany) were inserted in trabecular bone specimens. All implants were inserted with a torque up to 30 N·cm and loaded horizontally with 10, 20, and 30 N for 2 seconds. All implants showed primary stability. With increasing force, a gradual increase of micromovement was observed (Kruskal-Wallis test, P = 0.000). No significant differences were found (Kruskal-Wallis test, P = 0.148) comparing different diameters for every force. Variation of the diameter of standard implants between 3.25 and 4.5 mm does not seem to influence the primary stability in trabecular bone specimen. Differences between experimental and computational results may be due to the simplification used when modeling.

  20. Early infection risk with primary versus staged Hemodialysis Reliable Outflow (HeRO) graft implantation.

    PubMed

    Griffin, Andrew S; Gage, Shawn M; Lawson, Jeffrey H; Kim, Charles Y

    2017-01-01

    This study evaluated whether the use of a staged Hemodialysis Reliable Outflow (HeRO; Merit Medical, South Jordan, Utah) implantation strategy incurs increased early infection risk compared with conventional primary HeRO implantation. A retrospective review was performed of 192 hemodialysis patients who underwent HeRO graft implantation: 105 patients underwent primary HeRO implantation in the operating room, and 87 underwent a staged implantation where a previously inserted tunneled central venous catheter was used for guidewire access for the venous outflow component. Within the staged implantation group, 32 were performed via an existing tunneled hemodialysis catheter (incidentally staged), and 55 were performed via a tunneled catheter inserted across a central venous occlusion in an interventional radiology suite specifically for HeRO implantation (intentionally staged). Early infection was defined as episodes of bacteremia or HeRO infection requiring resection ≤30 days of HeRO implantation. For staged HeRO implantations, the median interval between tunneled catheter insertion and conversion to a HeRO graft was 42 days. The overall HeRO-related infection rate ≤30 days of implantation was 8.6% for primary HeRO implantation and 2.3% for staged implantations (P = .12). The rates of early bacteremia and HeRO resection requiring surgical resection were not significantly different between groups (P = .19 and P = .065, respectively), nor were age, gender, laterality, anastomosis to an existing arteriovenous access, human immunodeficiency virus status, diabetes, steroids, chemotherapy, body mass index, or graft location. None of the patient variables, techniques, or graft-related variables correlated significantly with the early infection rate. The staged HeRO implantation strategy did not result in an increased early infection risk compared with conventional primary implantation and is thus a reasonable strategy for HeRO insertion in hemodialysis patients

  1. Machined versus roughened immediately loaded and finally restored single implants inserted flapless: Preliminary 6-month data from a split- mouth randomised controlled trial.

    PubMed

    Cannizzaro, Gioacchino; Felice, Pietro; Loi, Ignazio; Viola, Paolo; Ferri, Vittorio; Leone, Michele; Lazzarini, Matteo; Trullenque-Eriksson, Anna; Esposito, Marco

    To compare the outcome of immediately loaded single implants with a machined or a roughened surface. Fifty patients had two implant sites randomly allocated to receive flaplessplaced single Syra implants (Sweden & Martina), one with a machined and one with a roughened surface (sand-blasted with zirconia powder and acid etched), according to a split-mouth design. To be loaded immediately, implants had to be inserted with a torque superior to 50 Ncm. Implants were restored with definitive crowns in direct occlusal contact within 48 h. Patients were followed for 6 months after loading. Outcome measures were prosthetic and implant failures and complications. Two machined implants and four roughened implants were not loaded immediately. Six months after loading no dropout occurred. One implant loaded late, which had a rough implant surface, failed 20 days after loading (P (McNemar test) = 0.625; difference in proportions = -0.04; 95% CI: -0.15 to 0.07). Three crowns had to be remade on machined implants and four on roughened implants (P (McNemar test) = 1.000; difference in proportions = -0.02; 95% CI: -0.12 to 0.08). Three machined and five roughened implants experienced complications (P (McNemar test) = 0.625; difference in proportions = -0.04; 95% CI: -0.15 to 0.07). There were no statistically significant differences between groups for crown and implant losses as well as complications. Up to 6 months after loading both machined and roughened flapless-placed and immediately loaded single implants provided good and similar results, however, longer follow-ups are needed to evaluate the long-term prognosis of implants with different surfaces.

  2. Antibiotic loaded calcium sulfate bead and pulse lavage eradicates biofilms on metal implant materials in vitro.

    PubMed

    Knecht, Cory S; Moley, James P; McGrath, Mary S; Granger, Jeffrey F; Stoodley, Paul; Dusane, Devendra H

    2018-03-30

    Pulse lavage (PL) debridement and antibiotic loaded calcium sulfate beads (CS-B) are both used for the treatment of biofilm related periprosthetic joint infection (PJI). However, the efficacy of these alone and in combination for eradicating biofilm from orthopaedic metal implant surfaces is unclear. The purpose of the study was to understand the efficacy of PL and antibiotic loaded CS-B in eradicating bacterial biofilms on 316L stainless steel (SS) alone and in combination in vitro. Biofilms of bioluminescent strains of Pseudomonas aeruginosa Xen41 and a USA300 MRSA Staphylococcus aureus SAP231 were grown on SS coupons for 3 days. The coupons were either, (i) debrided for 3 s with PL, (ii) exposed to tobramycin (TOB) and vancomycin (VAN) loaded CS-B for 24 h, or (iii) exposed to both. An untreated biofilm served as a control. The amount of biofilm was measured by bioluminescence, viable plate count and confocal microscopy using live/dead staining. PL alone reduced the CFU count of both strains of biofilms by approximately 2 orders of magnitude, from an initial cell count on metal surface of approximately 10 9 CFU/cm 2 . The antibiotic loaded CS-B caused an approximate six log reduction and the combination completely eradicated viable biofilm bacteria. Bioluminescence and confocal imaging corroborated the CFU data. While PL and antibiotic loaded CS-B both significantly reduced biofilm, the combination of two was more effective than alone in removing biofilms from SS implant surfaces. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 9999:1-6, 2018. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  3. Surface modification and fatigue behavior of nitinol for load bearing implants

    NASA Astrophysics Data System (ADS)

    Bernard, Sheldon A.

    Musculoskeletal disorders are recognized amongst the most significant human health problems that exist today. Even though considerable research and development has gone towards understanding musculoskeletal disorders, there is still lack of bone replacement materials that are appropriate for restoring lost structures and functions, particularly for load-bearing applications. Many materials on the market today, such as titanium and stainless steel, suffer from significantly higher modulus than natural bone and low bioactivity leading to stress shielding and implant loosening over longer time use. Nitinol (NiTi) is an equiatomic intermetallic compound of nickel and titanium whose unique biomechanical and biological properties contributed to its increasing use as a biomaterial. An innovative method for creating dense and porous net shape NiTi alloy parts has been developed to improve biological properties while maintaining comparable or better mechanical properties than commercial materials that are currently in use. Laser engineered net shaping (LENS(TM)) and surface electrochemistry modification was used to create dense/porous samples and micro textured surfaces on NiTi parts, respectively. Porous implants are known to promote cell adhesion and have a low elastic modulus, a combination that can significantly increase the life of an implant. However, porosity can significantly reduce the fatigue life of an implant, and very little work has been reported on the fatigue behavior of bulk porous metals, specifically on porous nitinol alloy. High-cycle rotating bending and compression-compression fatigue behavior of porous NiTi fabricated using LENS(TM) were studied. In cyclic compression loading, plastic strain increased with increasing porosity and it was evident that maximum strain was achieved during the first 50000 cycles and remained constant throughout the remaining loading. No failures were observed due to loading up to 150% of the yield strength. When subjected

  4. Feasibility of early discharge after implantable cardioverter-defibrillator procedures.

    PubMed

    Choudhuri, Indrajit; Desai, Dipan; Walburg, Jon; August, Phyllis; Keller, Seth I; Suri, Ranjit

    2012-10-01

    Registry data demonstrate considerably low complication rates after implantable cardioverter-defibrillator (ICD) procedures for primary prevention of sudden death. Yet standard of care includes postimplant overnight in-hospital observation that may levy substantial unnecessary financial burden on health care systems. In appropriate patients, discharge soon after implant could translate into significant cost savings, if such practice does not result in complications. We applied a simple clinical algorithm to assess feasibility of discharge on the same day of ICD implantation in patients at low risk for procedural complications. We prospectively randomized primary prevention ICD candidates at low risk for complications (not pacing-dependent or requiring bridging heparin anticoagulation) to next-day discharge with overnight in-hospital observation, or same-day discharge with remote monitoring for 24 hours after ICD implant. Implants were performed via cephalic vein access, and randomization occurred after 4-hours clinical observation and device interrogation. All patients were followed for a minimum of 6 weeks to assess acute procedural complications. 71 patients comprised the study cohort (mean age 62, 79% male) after 3 were excluded. The most common indication for ICD implant was ischemic cardiomyopathy with ejection fraction ≤35%. Device data obtained through 24-hour remote monitoring was comparable to 4-hour postimplant parameters in same-day discharge patients. No acute complications occurred in same-day discharge patients; 1 next-day discharge patient developed pneumothorax. ICD implantation with same-day discharge is reasonable in patients at low risk for complications. Remote monitoring can be useful in indicating lead-parameter stability during the immediate postoperative period. © 2012 Wiley Periodicals, Inc.

  5. Effects of immediate and delayed loading on peri-implant trabecular structures: a cone beam CT evaluation.

    PubMed

    Huang, Yan; Van Dessel, Jeroen; Liang, Xin; Depypere, Maarten; Zhong, Weijian; Ma, Guowu; Lambrichts, Ivo; Maes, Frederik; Jacobs, Reinhilde

    2014-12-01

    To develop a method for characterizing trabecular bone microarchitecture using cone beam computed tomography (CBCT) and to evaluate trabecular bone changes after rehabilitation using immediate versus delayed implant protocols. Six mongrel dogs randomly received 27 titanium implants in the maxillary incisor or mandibular premolar areas, following one of four protocols: (1) normal extraction socket healing; (2) immediate implant placement and immediate loading; (3) delayed implant placement and delayed loading; (4) delayed implant placement and immediate loading. The animals were euthanized at 8 weeks, and block biopsies were scanned using high resolution CBCT. Standard bone structural variables were assessed in coronal, middle, and apical levels. Coronal and middle regions had more compact, more platelike, and thicker trabeculae. Protocols (2), (3), and (4) had significantly higher values (p < 0.001) than protocol (1) for bone surface density, bone surface volume ratio, and connectivity density, while significantly lower values (p < 0.001) were found for trabecular separation and fractal dimension. However, protocols (2), (3), and (4) did not show significantly different bone remodeling. Compared with normal extraction healing, the implant protocols have an improved bone structural integration. Results do not suggest a different bone remodeling pattern when a delayed versus an immediate implant protocol is used. © 2013 Wiley Periodicals, Inc.

  6. Immediate and early function of Brånemark System implants placed in the esthetic zone: a 1-year prospective clinical multicenter study.

    PubMed

    Maló, Paulo; Friberg, Bertil; Polizzi, Giovanni; Gualini, Federico; Vighagen, Torbjörn; Rangert, Bo

    2003-01-01

    Immediate/early implant function means great benefits for patients and therapists because treatment time and cost can be substantially reduced. This concept has become an accepted alternative for complete arch fixed restorations in the mandible, and clinical documentation is emerging for other indications. The purpose of this prospective clinical multicenter study was to evaluate the outcome of implants placed in incisor, canine, and premolar regions in maxillas or mandibles. Implants were loaded with provisional crowns and bridges on the same day or within a few days and were followed up for 1 year during function. Four centers treated 76 patients each in need of an implant-retained prosthesis in the anterior and premolar regions in the maxilla or mandible. A total of 116 titanium implants with machined surfaces (Brånemark System , Nobel Biocare AB, Gothenburg, Sweden) were placed: 74 in maxillas and 42 in mandibles. Eighty-seven prostheses were made, of which 63 were single crowns and 24 were bridges (supported by 53 splinted implants). Twenty-two implants in 14 patients were placed in fresh extraction sites. The goal with the preparation and insertion technique was to achieve good primary implant stability and a minimum implant insertion torque of 30 Ncm before the implant was completely seated. The occlusion was adjusted to eliminate direct contact with the provisional prostheses. After 6 months, the patients received their permanent prostheses. Sixty-seven patients were followed for 1 year. Five implants were lost in five patients, three in the maxilla and two in the mandible. Four of the lost implants were single-tooth replacements and one was splinted. The cumulative survival rate (CSR) was 95.7% for all implants after 1 year and 93.7% and 98.1% for single-tooth and splinted implants, respectively. There were no implant losses in the extraction sites. The CSR of 96% at 1 year indicates that immediate function of Brånemark System implants placed in incisor

  7. Influence of semipermanent cement application used in immediately loaded, implant-supported restorations on crestal bone resorption.

    PubMed

    Błaszczyszyn, Artur; Kubasiewicz-Ross, Paweł; Gedrange, Tomasz; Dominiak, Marzena

    2013-01-01

    The paper presents clinical-radiological research on the impact of the new semi-cement luting agent in the immediately loaded implant-supported restoration on alveolar ridge resorption. 25 patients with a partially edentulous alveolar ridge in the anterior section of the maxilla or mandible were included in the study. The implants were inserted with the application of traditional burs or with a Piezosurgery device supplied by Mectron. Taking into account the method of implant bed preparation, the scientific material was divided into two groups. The implants were loaded immediately with single crown restorations cemented with the Implantlink semi cement application. The following indices were taken into consideration: pocket depth around implant calculated at four measuring points, marginal alveolar bone loss measured using radio-visiography, the 3-degree Wachtel scale of healing of the soft tissue. In addition, the presence and possible width or height of any recession around the implants was measured. The success of the implant treatment was assessed according to the Albrektsson success criteria. The research results were subjected to statistical analysis. The results of our study revealed no influence of the Implant-link semi cement on the crestal bone level, regardless of the bone bed preparation technique.

  8. Marginal bone-level alterations of loaded zirconia and titanium dental implants: an experimental study in the dog mandible.

    PubMed

    Thoma, Daniel S; Benic, Goran I; Muñoz, Fernando; Kohal, Ralf; Sanz Martin, Ignacio; Cantalapiedra, Antonio G; Hämmerle, Christoph H F; Jung, Ronald E

    2016-04-01

    The aim was to test whether or not the marginal bone-level alterations of loaded zirconia implants are similar to the bone-level alterations of a grade 4 titanium one-piece dental implant. In six dogs, all premolars and the first molars were extracted in the mandible. Four months later, three zirconia implants (BPI, VC, ZD) and a control titanium one-piece (STM) implant were randomly placed in each hemimandible and left for transmucosal healing (baseline). Six months later, CAD/CAM crowns were cemented. Sacrifice was scheduled at 6-month postloading. Digital X-rays were taken at implant placement, crowns insertion, and sacrifice. Marginal bone-level alterations were calculated, and intra- and intergroup comparisons performed adjusted by confounding factors. Implants were successfully placed. Until crown insertion, two implants were fractured (one VC, one ZD). At sacrifice, 5 more implants were (partly) fractured (one BPI, four ZD), and one lost osseointegration (VC). No decementation of crowns occurred. All implant systems demonstrated a statistically significant (except VC) loss of marginal bone between baseline and crown insertion ranging from 0.29 mm (VC; P = 0.116) to 0.80 mm (ZD; P = 0.013). The estimated marginal bone loss between baseline and 6 months of loading ranged between 0.19 mm (BPI) and 1.11 mm (VC), being statistically significant for STM and VC only (P < 0.05). The changes in marginal bone levels were statistically significantly different between zirconia implants and control implants (STM vs. BPI P = 0.007; vs. VC P = 0.001; vs. ZD P = 0.011). Zirconia implants were more prone to fracture prior to and after loading with implant-supported crowns compared to titanium implants. Individual differences and variability in the extent of the bone-level changes during the 12-month study period were found between the different implant types and materials. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. Efficient antitumor effect of co-drug-loaded nanoparticles with gelatin hydrogel by local implantation

    PubMed Central

    Zhang, Hao; Tian, Yong; Zhu, Zhenshu; Xu, Huae; Li, Xiaolin; Zheng, Donghui; Sun, Weihao

    2016-01-01

    Tetrandrine (Tet) could enhance the antitumor effect of Paclitaxel (Ptx) by increasing intracellular Reactive Oxygen Species (ROS) levels, which leads to the possibility of co-delivery of both drugs for synergistic antitumor effect. In the current study, we reported an efficient, local therapeutic strategy employing effective Tet and Ptx delivery with a nanoparticle-loaded gelatin system. Tet- and Ptx co-loaded mPEG-PCL nanoparticles (P/T-NPs) were encapsulated into the physically cross-linked gelatin hydrogel and then implanted on the tumor site for continuous drug release. The drug-loaded gelatin hydrogel underwent a phase change when the temperature slowly increased. In vitro study showed that Tet/Ptx-loaded PEG-b-PCL nanoparticles encapsulated within a gelatin hydrogel (P/T-NPs-Gelatin) inhibited the growth and invasive ability of BGC-823 cells more effectively than the combination of free drugs or P/T-NPs. In vivo study validated the therapeutic potential of P/T-NPs-Gelatin. P/T-NPs-Gelatin significantly inhibited the activation of p-Akt and the downstream anti-apoptotic Bcl-2 protein and also inducing the activation of pro-apoptotic Bax protein. Moreover, the molecular-modulating effect of P/T-NPs-Gelatin on related proteins varied slightly under the influence of NAC, which was supported by the observations of the tumor volumes and weights. Based on these findings, local implantation of P/T-NPs-Gelatin may be a promising therapeutic strategy for the treatment of gastric cancer. PMID:27226240

  10. Two Bilateral Zygomatic Implants Placed and Immediately Loaded: A Retrospective Chart Review with Up-to-54-Month Follow-up.

    PubMed

    Neugarten, Jay; Tuminelli, Frank J; Walter, Leora

    To report on the outcome of placement of two bilateral zygomatic implants with an immediately loaded prosthesis. A retrospective chart review was conducted of all patients treated with zygomatic implants between August 1, 2011 and June 6, 2016. All patients had at least two zygomatic implants placed bilaterally and immediately loaded with a provisional prosthesis the same day of implant placement. The implants were Nobel Biocare TiUnite or machined surface with lengths of 30 to 52.5 mm. All patients were treated by a team consisting of one surgeon, a restorative dentist or prosthodontist, an anesthesiologist, and a laboratory technician. Implant success was defined as successful integration of the implant; prosthetic success was defined as retention of the prosthesis under normal function. One hundred five zygomatic implants were placed and immediately loaded in 28 patients over a period of 1 to 60 months. Ages ranged from 46 to 81 years, with 26 female and 2 male patients. All the implants were placed by one surgeon. The immediate load on the day of implant placement was completed by either one of 2 prosthodontists or 11 restorative dentists. Implant success was 96% (101/105). All four failed implants were in one patient and were TiUnite surface coated. This study demonstrated that two zygomatic implants bilaterally placed and immediately loaded with a full-arch splinted prosthesis will provide a predictable outcome.

  11. Magnesium alloys as body implants: fracture mechanism under dynamic and static loadings in a physiological environment.

    PubMed

    Choudhary, Lokesh; Raman, R K Singh

    2012-02-01

    It is essential that a metallic implant material possesses adequate resistance to cracking/fracture under the synergistic action of a corrosive physiological environment and mechanical loading (i.e. stress corrosion cracking (SCC)), before the implant can be put to actual use. This paper presents a critique of the fundamental issues with an assessment of SCC of a rapidly corroding material such as magnesium alloys, and describes an investigation into the mechanism of SCC of a magnesium alloy in a physiological environment. The SCC susceptibility of the alloy in a simulated human body fluid was established by slow strain rate tensile (SSRT) testing using smooth specimens under different electrochemical conditions for understanding the mechanism of SCC. However, to assess the life of the implant devices that often possess fine micro-cracks, SCC susceptibility of notched specimens was investigated by circumferential notch tensile (CNT) testing. CNT tests also produced important design data, i.e. threshold stress intensity for SCC (KISCC) and SCC crack growth rate. Fractographic features of SCC were examined using scanning electron microscopy. The SSRT and CNT results, together with fractographic evidence, confirmed the SCC susceptibility of both smooth and notched specimens of a magnesium alloy in the physiological environment. Copyright © 2011 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  12. Immediate Functional Loading of One-Piece Zirconia Implants in a Full-Arch Maxillary Restoration: A Five-Year Case Report.

    PubMed

    Peter, Burghard

    Immediate loading has proven to be a predictable modality for restorations with titanium dental implants. An increasing number of articles indicate that zirconia implants might osseointegrate to a similar extent in this context. This 5-year case report describes an outpatient maxillary restoration with eight immediately loaded zirconia implants. Implantation followed extensive bone augmentation. At the 5-year follow-up, all implants were still well osseointegrated clinically and radiologically. No major bone loss or peri-implantitis had occurred in spite of temporary insufficient patient compliance. More research and studies are needed to confirm these results.

  13. Immediate loading of implants placed in patients with untreated periodontal disease: a 5-year prospective cohort study.

    PubMed

    Maló, Paulo; Nobre, Miguel de Araújo; Lopes, Armando; Ferro, Ana; Gravito, Inês

    2014-01-01

    To report the 5-year outcome of immediately loaded dental implants in patients with untreated periodontal disease. This prospective cohort study included 103 consecutive patients (51 females and 52 males) with an average age of 52 years (range: 22 to 80 years) who were rehabilitated with 380 implants supporting 145 prostheses in both jaws (40 single; 33 partial and 72 complete rehabilitations). The implants were inserted in patients with active and untreated periodontitis. The patients did not receive any previous periodontal treatment before implant surgery, except for an oral hygiene session immediately before the implant surgery. In maintenance (every 6 months) patients received periodontal treatment as needed. Outcome measures were: prostheses failures; implant failures; complications; and marginal bone level changes. Fifteen patients dropped out of the study (14.6%). Two patients lost two implants (FDI positions nos.12 and 42), rendering a cumulative survival rate of 97.9% and 99.4% at 5 years of followup using the patient and implant as unit of analysis, respectively. The average (standard deviation) marginal bone resorption was 0.71 mm (0.42 mm) at 5 years. Mechanical complications occurred in 14 patients, consisting of prostheses fractures (10 provisional prostheses and 4 definitive prostheses). Thirteen implants (3.9%) in 13 patients (14.8%) presented peri-implant pathology. Within the limitations of this study, it is possible to conclude that the rehabilitation of patients with untreated periodontitis using immediately loaded dental implants is feasible in the medium-term, when periodontal therapy is provided after rehabilitation and the patients are regularly maintained.

  14. Biodegradation and cytotoxicity of ciprofloxacin-loaded hydroxyapatite-polycaprolactone nanocomposite film for sustainable bone implants.

    PubMed

    Nithya, Rajendran; Meenakshi Sundaram, Nachiappan

    2015-01-01

    In recent years there has been a steep increase in the number of orthopedic patients for many reasons. One major reason is osteomyelitis, caused by pyrogenic bacteria, with progressive infection of the bone or bone marrow and surrounding tissues. So antibiotics must be introduced during bone implantation to avoid prolonged infection. The objective of the study reported here was to prepare a composite film of nanocrystalline hydroxyapatite (HAp) and polycaprolactone (PCL) polymer loaded with ciprofloxacin, a frequently used antibiotic agent for bone infections. Nanocrystalline HAp was synthesized by precipitation method using the precursor obtained from eggshell. The nanocomposite film (HAp-PCL-ciprofloxacin) was prepared by solvent evaporation. Drug-release and biodegradation studies were undertaken by immersing the composite film in phosphate-buffered saline solution, while a cytotoxicity test was performed using the fibroblast cell line NIH-3T3 and osteoblast cell line MG-63. The pure PCL film had quite a low dissolution rate after an initial sharp weight loss, whereas the ciprofloxacin-loaded HAp-PCL nanocomposite film had a large weight loss due to its fast drug release. The composite film had higher water absorption than the pure PCL, and increasing the concentration of the HAp increased the water absorption. The in vitro cell-line study showed a good biocompatibility and bioactivity of the developed nanocomposite film. The prepared film will act as a sustainable bone implant in addition to controlled drug delivery.

  15. Single dental implant retained mandibular complete dentures – influence of the loading protocol: study protocol for a randomized controlled trial

    PubMed Central

    2014-01-01

    Background Over the years, there has been a strong consensus in dentistry that at least two implants are required to retain a complete mandibular denture. It has been shown in several clinical trials that one single median implant can retain a mandibular overdenture sufficiently well for up to 5 years without implant failures, when delayed loading was used. However, other trials have reported conflicting results with in part considerable failure rates when immediate loading was applied. Therefore it is the purpose of the current randomized clinical trial to test the hypothesis that immediate loading of a single mandibular midline implant with an overdenture will result in a comparable clinical outcome as using the standard protocol of delayed loading. Methods/design This prospective nine-center randomized controlled clinical trial is still ongoing. The final patient will complete the trial in 2016. In total, 180 edentulous patients between 60 and 89 years with sufficient complete dentures will receive one median implant in the edentulous mandible, which will retain the existing complete denture using a ball attachment. Loading of the median implant is either immediately after implant placement (experimental group) or delayed by 3 months of submerged healing at second-stage surgery (control group). Follow-up of patients will be performed for 24 months after implant loading. The primary outcome measure is non-inferiority of implant success rate of the experimental group compared to the control group. The secondary outcome measures encompass clinical, technical and subjective variables. The study was funded by the Deutsche Forschungsgemeinschaft (German research foundation, KE 477/8-1). Discussion This multi-center clinical trial will give information on the ability of a single median implant to retain a complete mandibular denture when immediately loaded. If viable, this treatment option will strongly improve everyday dental practice. Trial registration The trial

  16. Histologic and histomorphometric evaluation of peri-implant bone of immediate or delayed occlusal-loaded non-splinted implants in the posterior mandible--an experimental study in monkeys.

    PubMed

    Stokholm, Rie; Isidor, Flemming; Nyengaard, Jens R

    2014-11-01

    The primary aim of this study was to compare the bone reaction around immediate-loaded non-splinted single implants vs. delayed loaded non-splinted single implants placed in healed ridges in the posterior mandible. Six adult Macaca Fascicularis monkeys were used in this study. The first and second premolars and the first molar were extracted in both sides of the mandible. After 3 months of healing, four implants (Replace Select Tapered; Nobel Biocare, Gothenburg, Sweden) with a moderately rough surface (TiUnite, Nobel Biocare) were placed in the edentulous areas of each monkey, two in each side. The implants had a length of 10 mm and a diameter of 3.5 mm. Four groups of varying time and occlusal loading aspects were created: (i) control group: implant placed non-loaded for 3 months; (ii) immediate loaded: implant placed and loaded immediately for 3 months; (iii) immediate loaded: implant placed and loaded immediately for 6 months; and (iv) delayed loaded: implant placed submerged for 3 months and then loaded for 3 months. At the loaded implants, after a second stage surgery, a composite crown was made directly on an abutment mounted on the implant reinsuring simultaneous occlusal contact on the implant crown and the neighboring teeth. After euthanization of the animals, histologic specimens were quantified in the light microscope. All implants were clinically, radiographically, and histologically osseointegrated at the time of euthanization and with only mild signs of inflammation in the peri-implant mucosa. The histologic marginal bone level was located on average 1.14-1.74 mm apical to the margin of the implants in the various groups. The average bone-to-implant contact (BIC) varied between 55% and 65% and the average bone density (i.e., the proportion of mineralized bone tissue from the implant surface and to a distance of 1 mm lateral to the implant) varied between 30.6% and 34.2%. No statistical significant differences between groups were observed in

  17. Electrophoretic deposition of gentamicin-loaded bioactive glass/chitosan composite coatings for orthopaedic implants.

    PubMed

    Pishbin, Fatemehsadat; Mouriño, Viviana; Flor, Sabrina; Kreppel, Stefan; Salih, Vehid; Ryan, Mary P; Boccaccini, Aldo R

    2014-06-11

    Despite their widespread application, metallic orthopaedic prosthesis failure still occurs because of lack of adequate bone-bonding and the incidence of post-surgery infections. The goal of this research was to develop multifunctional composite chitosan/Bioglass coatings loaded with gentamicin antibiotic as a suitable strategy to improve the surface properties of metallic implants. Electrophoretic deposition (EPD) was applied as a single-step technology to simultaneously deposit the biopolymer, bioactive glass particles, and the antibiotic on stainless steel substrate. The microstructure and composition of the coatings were characterized using SEM/EDX, XRD, FTIR, and TGA/DSC, respectively. The in vitro bioactivity of the coatings was demonstrated by formation of hydroxyapatite after immersion in simulated body fluid (SBF) in a short period of 2 days. High-performance liquid chromatography (HPLC) measurements indicated the release of 40% of the loaded gentamicin in phosphate buffered saline (PBS) within the first 5 days. The developed composite coating supported attachment and proliferation of MG-63 cells up to 10 days. Moreover, disc diffusion test showed improved bactericidal effect of gentamicin-loaded composite coatings against S. aureus compared to control non-gentamicin-loaded coatings.

  18. Enduring Advantages of Early Cochlear Implantation for Spoken Language Development

    PubMed Central

    Geers, Ann E.; Nicholas, Johanna G.

    2013-01-01

    Purpose To determine whether the precise age of implantation (AOI) remains an important predictor of spoken language outcomes in later childhood for those who received a cochlear implant (CI) between 12–38 months of age. Relative advantages of receiving a bilateral CI after age 4.5, better pre-CI aided hearing, and longer CI experience were also examined. Method Sixty children participated in a prospective longitudinal study of outcomes at 4.5 and 10.5 years of age. Twenty-nine children received a sequential second CI. Test scores were compared to normative samples of hearing age-mates and predictors of outcomes identified. Results Standard scores on language tests at 10.5 years of age remained significantly correlated with age of first cochlear implantation. Scores were not associated with receipt of a second, sequentially-acquired CI. Significantly higher scores were achieved for vocabulary as compared with overall language, a finding not evident when the children were tested at younger ages. Conclusion Age-appropriate spoken language skills continued to be more likely with younger AOI, even after an average of 8.6 years of additional CI use. Receipt of a second implant between ages 4–10 years and longer duration of device use did not provide significant added benefit. PMID:23275406

  19. Levetiracetam-loaded biodegradable polymer implants in the tetanus toxin model of temporal lobe epilepsy in rats.

    PubMed

    Halliday, Amy J; Campbell, Toni E; Nelson, Timothy S; McLean, Karen J; Wallace, Gordon G; Cook, Mark J

    2013-01-01

    Approximately one-third of people with epilepsy receive insufficient benefit from currently available anticonvulsant medication, and some evidence suggests that this may be due to a lack of effective penetration into brain parenchyma. The current study investigated the ability of biodegradable polymer implants loaded with levetiracetam to ameliorate seizures following implantation above the motor cortex in the tetanus toxin model of temporal lobe epilepsy in rats. The implants led to significantly shorter seizures and a trend towards fewer seizures for up to 1 week. The results of this study indicate that drug-eluting polymer implants represent a promising evolving treatment option for intractable epilepsy. Future research is warranted to investigate issues of device longevity and implantation site. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Load-bearing capacity of screw-retained CAD/CAM-produced titanium implant frameworks (I-Bridge®2) before and after cyclic mechanical loading.

    PubMed

    Dittmer, Marc Philipp; Nensa, Moritz; Stiesch, Meike; Kohorst, Philipp

    2013-01-01

    Implant-supported screw-retained fixed dental prostheses (FDPs) produced by CAD/ CAM have been introduced in recent years for the rehabilitation of partial or total endentulous jaws. However, there is a lack of data about the long-term mechanical characteristics. The aim of this study was to investigate the failure mode and the influence of extended cyclic mechanical loading on the load-bearing capacity of these frameworks. Ten five-unit FDP frameworks simulating a free-end situation in the mandibular jaw were manufactured according to the I-Bridge®2-concept (I-Bridge®2, Biomain AB, Helsingborg, Sweden) and each was screw-retained on three differently angulated Astra Tech implants (30º buccal angulation/0º angulation/30º lingual angulation). One half of the specimens was tested for static load-bearing capacity without any further treatment (control), whereas the other half underwent five million cycles of mechanical loading with 100 N as the upper load limit (test). All specimens were loaded until failure in a universal testing machine with an occlusal force applied at the pontics. Load-displacement curves were recorded and the failure mode was macro- and microscopically analyzed. The statistical analysis was performed using a t-test (p=0.05). All the specimens survived cyclic mechanical loading and no obvious failure could be observed. Due to the cyclic mechanical loading, the load-bearing capacity decreased from 8,496 N±196 N (control) to 7,592 N±901 N (test). The cyclic mechanical loading did not significantly influence the load-bearing capacity (p=0.060). The failure mode was almost identical in all specimens: large deformations of the framework at the implant connection area were obvious. The load-bearing capacity of the I-Bridge®2 frameworks is much higher than the clinically relevant occlusal forces, even with considerably angulated implants. However, the performance under functional loading in vivo depends on additional aspects. Further studies are

  1. Load-bearing capacity of screw-retained CAD/CAM-produced titanium implant frameworks (I-Bridge®2) before and after cyclic mechanical loading

    PubMed Central

    DITTMER, Marc Philipp; NENSA, Moritz; STIESCH, Meike; KOHORST, Philipp

    2013-01-01

    Implant-supported screw-retained fixed dental prostheses (FDPs) produced by CAD/ CAM have been introduced in recent years for the rehabilitation of partial or total endentulous jaws. However, there is a lack of data about the long-term mechanical characteristics. Objective The aim of this study was to investigate the failure mode and the influence of extended cyclic mechanical loading on the load-bearing capacity of these frameworks. Material and Methods Ten five-unit FDP frameworks simulating a free-end situation in the mandibular jaw were manufactured according to the I-Bridge®2-concept (I-Bridge®2, Biomain AB, Helsingborg, Sweden) and each was screw-retained on three differently angulated Astra Tech implants (30º buccal angulation/0º angulation/30º lingual angulation). One half of the specimens was tested for static load-bearing capacity without any further treatment (control), whereas the other half underwent five million cycles of mechanical loading with 100 N as the upper load limit (test). All specimens were loaded until failure in a universal testing machine with an occlusal force applied at the pontics. Load-displacement curves were recorded and the failure mode was macro- and microscopically analyzed. The statistical analysis was performed using a t-test (p=0.05). Results All the specimens survived cyclic mechanical loading and no obvious failure could be observed. Due to the cyclic mechanical loading, the load-bearing capacity decreased from 8,496 N±196 N (control) to 7,592 N±901 N (test). The cyclic mechanical loading did not significantly influence the load-bearing capacity (p=0.060). The failure mode was almost identical in all specimens: large deformations of the framework at the implant connection area were obvious. Conclusion The load-bearing capacity of the I-Bridge®2 frameworks is much higher than the clinically relevant occlusal forces, even with considerably angulated implants. However, the performance under functional loading in vivo

  2. Early bone anchorage to micro- and nano-topographically complex implant surfaces in hyperglycemia.

    PubMed

    Ajami, Elnaz; Bell, Spencer; Liddell, Robert S; Davies, John E

    2016-07-15

    The aim of this work was to investigate the effect of implant surface design on early bone anchorage in the presence of hyperglycemia. 108 Wistar rats were separated into euglycemic (EG) controls and STZ-treated hyperglycemic (HG) groups, and received bilateral femoral custom rectangular implants of two surface topographies: grit blasted (GB) and grit-blast with a superimposed calcium phosphate nanotopography (GB-DCD). The peri-implant bone was subjected to a tensile disruption test 5, 7, and 9days post-operatively (n=28/time point); the force was measured; and the residual peri-implant bone was observed by scanning electron microscopy (SEM). Disruption forces at 5days were not significantly different from zero for the GB implants (p=0.24) in either metabolic group; but were for GB+DCD implants in both metabolic groups (p<0.001). Contact osteogenesis was greater on GB-DCD than the GB surface. The nano-and micro-surfaced implants showed significantly different disruption forces at all time points (e.g. >15N and <5N respectively at 9days). Such differences were not seen within the GB implants, as all values were very low (<5N). Even in hyperglycemia the GB-DCD surface outperformed the GB surfaces in both metabolic groups. Significantly, SEM of peri-implant bone showed compromised intra-fibrillar collagen mineralization in hyperglycemia, while inter-fibrillar and cement line mineralization remained unaffected. Enhanced bone anchorage to the implant surfaces was observed on the nanotopographically complex surface independent of metabolic group. The compromised intra-fibrillar mineralization observed provides a mechanism by which early bone mineralization is affected in hyperglycemia. It is generally accepted that the hyperglycemia associated with diabetes mellitus compromises bone quality, although the mechanism by which this occurs is unknown. Uncontrolled hyperglycemia is therefore a contra-indication for bone implant placement. It is also known that nano

  3. Life prediction of different commercial dental implants as influence by uncertainties in their fatigue material properties and loading conditions.

    PubMed

    Pérez, M A

    2012-12-01

    Probabilistic analyses allow the effect of uncertainty in system parameters to be determined. In the literature, many researchers have investigated static loading effects on dental implants. However, the intrinsic variability and uncertainty of most of the main problem parameters are not accounted for. The objective of this research was to apply a probabilistic computational approach to predict the fatigue life of three different commercial dental implants considering the variability and uncertainty in their fatigue material properties and loading conditions. For one of the commercial dental implants, the influence of its diameter in the fatigue life performance was also studied. This stochastic technique was based on the combination of a probabilistic finite element method (PFEM) and a cumulative damage approach known as B-model. After 6 million of loading cycles, local failure probabilities of 0.3, 0.4 and 0.91 were predicted for the Lifecore, Avinent and GMI implants, respectively (diameter of 3.75mm). The influence of the diameter for the GMI implant was studied and the results predicted a local failure probability of 0.91 and 0.1 for the 3.75mm and 5mm, respectively. In all cases the highest failure probability was located at the upper screw-threads. Therefore, the probabilistic methodology proposed herein may be a useful tool for performing a qualitative comparison between different commercial dental implants. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  4. Implant Dentistry: Monitoring of Bacteria Along the Transmucosal Passage of the Healing Screw in Absence of Functional Load

    PubMed Central

    MEYNARDI, F.; PASQUALINI, M.E.; ROSSI, F.; DAL CARLO, L.; NARDONE, M.; BAGGI, L.

    2016-01-01

    SUMMARY Purpose To assess the changes in bacterial profile along the transmucosal path of healing screws placed immediately after insertion of two-piece endosseus implants during the 4-month osseointegration phase, in absence of functional load. Materials and methods Two site-specific samples were collected at the peri-implant mucosa of the healing screws of 80 two-piece implants, for a total of 640 samples. Implants placement was performed following a single protocol with flapless technique, in order to limit bacterial contamination of the surgical site. Identical healing screws (5 mm diameter/4 mm height) were used for each of the 80 implants. During the 4 months of the study, the patients followed a standard oral care regimen with no special hygiene maneuvers at the collection sites. Results The present research documents that during the 4-month period prior to application of function load the bacterial profile of all sites exhibited a clear prevalence of cocci at the interface between implant neck and osteoalveolar crest margin. Conclusions A potentially pathogenic bacterial flora developed only along the peri-implant transmucosal path. PMID:28280528

  5. The effects of dynamic compressive loading on biodegradable implants of 50-50% polylactic Acid-polyglycolic Acid.

    PubMed

    Thompson, D E; Agrawal, C M; Athanasiou, K

    1996-01-01

    Biodegradable implants that release growth factors or other bioactive agents in a controlled manner are investigated to enhance the repair of musculoskeletal tissues. In this study, the in vitro release characteristics and mechanical properties of a 50:50 polylactic acid/polyglycolic acid two phase implant were examined over a 6-week period under no-load conditions or under a cyclic compressive load, such as that experienced when walking slowly during rehabilitation. The results demonstrated that a cyclic compressive load significantly slows the decrease of molecular chain size during the first week, significantly increases protein release for the first 2-3 weeks, and significantly stiffens the implant for the first 3 weeks. It was also shown that protein release is initially high and steadily decreases with time until the molecular weight declines to about 20% of its original value (approximately 4 weeks). Once this threshold is reached, increased protein release, surface deformation, and mass loss occurs. This study also showed that dynamic loading and the environment in which an implant is placed affect its biodegradation. Therefore, it may be essential that in vitro degradation studies of these or similar implants include a dynamic functional environment.

  6. Does antibiotic prophylaxis at implant placement decrease early implant failures? A Cochrane systematic review.

    PubMed

    Esposito, Marco; Grusovin, Maria Gabriella; Loli, Vasiliki; Coulthard, Paul; Worthington, Helen V

    2010-01-01

    Marco Esposito is the first author of two of the included studies; however, he was not involved in the quality assessment of these trials. This review is based on a Cochrane systematic review entitled 'Interventions for replacing missing teeth: antibiotics at dental implant placement to prevent complications' published in The Cochrane Library (see http://www.cochrane.org for more information). Cochrane systematic reviews are regularly updated to include new research, and in response to comments and criticisms from readers. If you wish to comment on this review, please send your comments to the Cochrane website or to Marco Esposito. The Cochrane Library should be consulted for the most recent version of the review. The results of a Cochrane Review can be interpreted differently, depending on people's perspectives and circumstances. Please consider the conclusions presented carefully. They are the opinions of the review authors, and are not necessarily shared by the Cochrane Collaboration. To assess the beneficial or harmful effects of systemic prophylactic antibiotics at dental implant placement versus no antibiotic/placebo administration and, if antibiotics are of benefit, to find which type, dosage and duration is the most effective. The Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE were searched up to 2 June 2010 for randomised controlled clinical trials (RCTs) with a follow-up of at least 3 months comparing the administration of various prophylactic antibiotic regimens versus no antibiotics to patients undergoing dental implant placement. Outcome measures were prosthesis failures, implant failures, postoperative infections and adverse events (gastrointestinal, hypersensitivity, etc.). Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were conducted in duplicate and independently by two review authors. Meta-analyses were

  7. Pacemaker implantation rate after transcatheter aortic valve implantation with early and new-generation devices: a systematic review.

    PubMed

    van Rosendael, Philippe J; Delgado, Victoria; Bax, Jeroen J

    2018-06-01

    The incidence of new-onset conduction abnormalities requiring permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) with new-generation prostheses remains debated. This systematic review analyses the incidence of PPI after TAVI with new-generation devices and evaluates the electrical, anatomical, and procedural factors associated with PPI. In addition, the incidence of PPI after TAVI with early generation prostheses was reviewed for comparison. According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist, this systematic review screened original articles published between October 2010 and October 2017, reporting on the incidence of PPI after implantation of early and new-generation TAVI prostheses. Of the 1406 original articles identified in the first search for new-generation TAVI devices, 348 articles were examined for full text, and finally, 40 studies (n = 17 139) were included. The incidence of a PPI after the use of a new-generation TAVI prosthesis ranged between 2.3% and 36.1%. For balloon-expandable prostheses, the PPI rate remained low when using an early generation SAPIEN device (ranging between 2.3% and 28.2%), and with the new-generation SAPIEN 3 device, the PPI rate was between 4.0% and 24.0%. For self-expandable prostheses, the PPI rates were higher with the early generation CoreValve device (16.3-37.7%), and despite a reduction in PPI rates with the new Evolut R, the rates remained relatively higher (14.7-26.7%). When dividing the studies according to the highest (>26.0%) and the lowest (<12.1%) quintile of PPI rate, patients within the highest quintile were more frequently women when compared with the lowest quintile group (50.9% vs. 46.3%, P < 0.001). Pre-existent conduction abnormalities (electrical factor), calcification of the left ventricular outflow tract (anatomical factor), and balloon valvuloplasty and depth of implantation (procedural factors) were associated

  8. Effect of abutment screw length and cyclic loading on removal torque in external and internal hex implants.

    PubMed

    Mohammed, Hnd Hadi; Lee, Jin-Han; Bae, Ji-Myung; Cho, Hye-Won

    2016-02-01

    The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading.

  9. Effect of abutment screw length and cyclic loading on removal torque in external and internal hex implants

    PubMed Central

    Mohammed, Hnd Hadi; Lee, Jin-Han; Bae, Ji-Myung

    2016-01-01

    PURPOSE The purpose of this study was to evaluate the effects of abutment screw length and cyclic loading on the removal torque (RTV) in external hex (EH) and internal hex (IH) implants. MATERIALS AND METHODS Forty screw-retained single crowns were connected to external and internal hex implants. The prepared titanium abutment screws were classified into 8 groups based on the number of threads (n = 5 per group): EH 12.5, 6.5, 3.5, 2.5 and IH 6.5, 5, 3.5, 2.5 threads. The abutment screws were tightened with 20 Ncm torque twice with 10-minute intervals. After 5 minutes, the initial RTVs of the abutment screws were measured with a digital torque gauge (MGT12). A customized jig was constructed to apply a load along the implant long axis at the central fossa of the maxillary first molar. The post-loading RTVs were measured after 16,000 cycles of mechanical loading with 50 N at a 1-Hz frequency. Statistical analysis included one-way analysis of variance and paired t-tests. RESULTS The post-loading RTVs were significantly lower than the initial RTVs in the EH 2.5 thread and IH 2.5 thread groups (P<.05). The initial RTVs exhibited no significant differences among the 8 groups, whereas the post-loading RTVs of the EH 6.5 and EH 3.5 thread groups were higher than those of the IH 3.5 thread group (P<.05). CONCLUSION Within the limitations of this study, the external hex implants with short screw lengths were more advantageous than internal hex implants with short screw lengths in torque maintenance after cyclic loading. PMID:26949489

  10. Radiographic and clinical outcomes of implants placed in ridge preserved sites: a 12-month post-loading follow-up.

    PubMed

    Patel, K; Mardas, N; Donos, N

    2013-06-01

    The aim of this clinical study was to evaluate the interproximal radiographic bone levels and the survival/success rate of dental implants placed in alveolar ridges previously preserved with a synthetic bone substitute or a bovine xenograft. Alveolar ridge preservation was performed in 27 patients who were randomly assigned in two groups. In the test group (n = 14), the extraction socket was treated with a synthetic bone graft Straumann Bone Ceramic; SBC and a collagen barrier, whereas in the control group (n = 13) a deproteinized bovine bone mineral (DBBM) and the same collagen barrier were used. After 8 months of healing, titanium dental implants with a hydrophilic surface were placed in the preserved ridges. During surgery, 9/13 implants in the SBC group and 8/12 implants in the DBBM group presented with either dehiscence or fenestration defects and required additional bone augmentation. The implants were loaded at 4 months following placement and were followed up for 1 year post-loading. Interproximal radiographic bone levels were evaluated in standardized periapical radiographs at loading and 1 year post-loading. Probing pocket depth, gingival recession and bleeding upon probing were recorded at implants and neighbouring teeth. The success rate of the implants was evaluated according to criteria set by Albrektsson et al. (1986). The survival rate of the implants in both groups was 100% at 1-year post-loading. No statistically significant differences in any of the clinical and radiographic measurements were detected between the two groups (P < 0.05). The success rate of the implants was 84.6% (11/13) in the SBC group and 83.3% (10/12) in the DBBM group. Equivalent success and survival rates (as well as similar radiographic changes) of dental implants placed in alveolar ridges previously preserved with SBC or DBBM should be anticipated. © 2012 John Wiley & Sons A/S.

  11. Long-Term Mortality Effect of Early Pacemaker Implantation After Surgical Aortic Valve Replacement.

    PubMed

    Greason, Kevin L; Lahr, Brian D; Stulak, John M; Cha, Yong-Mei; Rea, Robert F; Schaff, Hartzell V; Dearani, Joseph A

    2017-10-01

    The need for pacemaker implantation is a well-described complication of aortic valve replacement. Not so well described is the effect such an event has on long-term outcome. This study reviewed a 21-year experience at the Mayo Clinic (Rochester, Minnesota) with aortic valve replacement to understand the influence of early postoperative pacemaker implantation on long-term mortality rates more clearly. This study retrospectively reviewed the records of 5,842 patients without previous pacemaker implantation who underwent surgical aortic valve replacement from January 1993 through June 2014. The median age of these patients was 73 years (range, 65 to 79 years), the median ejection fraction was 62% (range, 53% to 68%), 3,853 patients were male (66%), and coronary artery bypass graft operation was performed in 2,553 (44%) of the patients studied. Early pacemaker implantation occurred in 146 patients (2.5%) within 30 days of surgical aortic valve replacement. The median follow-up of patients was 11.1 years (range, 5.8 to 16.5 years), and all-cause mortality rates were 2.4% at 30 days, 6.4% at 1 year, 23.1% at 5 years, 48.3% at 10 years, and 67.9% at 15 years postoperatively. Early pacemaker implantation was associated with an increased risk of death after multivariable adjustment for baseline patients' characteristics (hazard ratio, 1.49; 95% confidence interval, 1.20, 1.84; p < 0.001). Early pacemaker implantation as a complication of surgical aortic valve replacement is associated with an increased risk of long-term death. Valve replacement-related pacemaker implantation rates should be important considerations with respect to new valve replacement paradigms, especially in younger and lower-risk patients. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  12. [An assessment tool for analysing the early vocal development of young children with cochlear implant].

    PubMed

    Lang, S; Leistner, S; Sandrieser, P; Kröger, B J

    2009-05-01

    Early vocal development of German-speaking cochlear implant recipients has rarely been assessed so far. There-fore the purpose of this study was to describe the early vocal development following successful implantation. A case study was designed to assess the temporal progression of early vocal development in a young cochlear implant recipient who was bilaterally implanted at the age of 8;3 months. Data were collected during one year by recording parent-child interactions on a monthly basis. The first recording was made before the onset of the signal-processors, the 12 following recordings were made during the first year of implant use. The child's vocalizations were classified according to the vocalization categories and developmental levels from the Stark Assessment of Early Vocal Development--Revised (SAEVD-R). This assessment tool was translated into German in this study and used with German-speaking children for the first time. It allows a coding of prelinguistic utterances via auditory perceptual analysis. The results show an overall decrease of early vocalizations and an increase of speech-like vowels and consonants. In the first six months no apparent progress took place; The child produced almost exclusively vocalizations from Levels 1-3. In the second half of the year an increase of canonical utterances (Level 4) and advanced forms (Level 5) was observed. However, vocalizations beyond the canonical babbling phase, especially vocants and closants as well as their combinations, continued to be dominant throughout the first year of implant use. The progress of development of the child investigated in this study is comparable to other children implanted at young age who had also been assessed with the SAEVD-R. In comparison to normal-hearing children, the implanted child's development seemed to progress slightly faster. Interrater- and intrarater-reliability using the SAEVD-R were measured for two independent observers and for a first and second coding

  13. The effect of number and distribution of unsplinted maxillary implants on the load transfer in implant-retained maxillary overdentures: an in vitro study.

    PubMed

    Damghani, Sahar; Masri, Radi; Driscoll, Carl F; Romberg, Elaine

    2012-06-01

    There is little information as to how the number and distribution of implants affect the amount of load transmitted to the palate in implant-retained maxillary overdentures. The purpose of this study was to evaluate the effect of the number and distribution of dental implants on the load transmitted to the palate. Eight implant analogues were placed in a replica of an average sized edentulous maxilla corresponding to the position of canines, first and second premolars, and first molars. The anteroposterior distance between the centers of implants in each quadrant was 8 mm. Fifteen denture bases were fabricated to fit the edentulous maxilla analogue. The denture bases were attached to the oral analogue using 6 different configurations of attachments (6 groups): Either no Locator attachments were used (control group), or the 2 most anterior attachments were attached, or 4 implants were engaged with a distance of 8, 16, or 24 mm between the centers of implants on left and right side, and finally, when all 8 attachments were activated. A force-measuring sensor was used to measure the force transmitted to the palate when a static force of 245 N was applied on the occlusal rims of the denture bases. Data (Newtons) were analyzed using 1-way ANOVA and Tukey's HSD test α=.05). The mean (SD) amount of force measured on the palate when the overdentures were supported by 4 Locator attachments; [49.84 (26.52) at 8 mm spacing], [24.42 (15.05) at 16 mm spacing], [35.66 (22.94) at 24 mm spacing] was significantly lower than when no attachments [90.98 (20.20), control], or when 2 Locator attachments were used [76.07 (27.63)] (P<.001). When the overdentures were supported by 8 Locator attachments, the force measured on the palate [20.67(16.06) N] was significantly lower than that for the control group (P<.001), overdentures supported by 2 Locator attachments (P<.001), and overdentures supported by 4 Locator attachments when the distance between the anterior and posterior implants

  14. [Osteoclasts and early bone remodeling after orthodontic micro-implant placement].

    PubMed

    Zhang, Wei; Guo, Jia-jia; Zhu, Wen-qian; Tang, Guo-hua

    2013-08-01

    To observe the incidence of osteoclasts during early bone remodeling after orthodontic micro-implant placement. Twenty New Zealand rabbits were randomly allotted into 4 groups. One micro-implant was implanted proximal to the epiphyseal plate of the tibia. Animals were sacrificed on day 3, 7, 14 and 28 (n=5). The sequence of histological changes around the micro-implants were evaluated by hematoxylin and eosin (HE) staining. Osteoclasts were identified by TRAP staining. The differences of the number of the osteoclasts among each time point were analyzed by one way ANOVA with SPSS 19.0 software package. After 3 days of implantation, a large number of erythrocytes, inflammatory cells, mesenchymal cells and bone debris were seen at the implant bone interfaces. Few osteoclasts were observed. On day 7, granular woven bone was formed and some osteoclasts were found in the Howship's lacunae. New bone formation and mineralization were apparent on day 14. Meanwhile, large amounts of osteoclasts were found in the latticed woven bone. On day 28, woven trabeculae with lamellate structures connected to lamellar bone and fewer osteoclasts were identified. Semi-quantitative analysis showed that the number of the osteoclasts was at peak on day 14. There were significant differences among each time point (P<0.01). Osteoclast activity is closely related to bone formation and remodeling after micro-implant insertion.

  15. Comparison of patient-reported outcomes between immediately and conventionally loaded mandibular two-implant overdentures: A preliminary study.

    PubMed

    Omura, Yuri; Kanazawa, Manabu; Sato, Daisuke; Kasugai, Shohei; Minakuchi, Shunsuke

    2016-07-01

    The aim of this preliminary study is to compare patient-reported outcomes between immediately and conventionally loaded mandibular two-implant overdentures retained by magnetic attachments. Nineteen participants with edentulous mandibles were randomly assigned into either an immediate loading group (immediate group) or a conventional loading group (conventional group). Each participant received 2 implants in the inter-foraminal region by means of flapless surgery. Prostheses in the immediate and conventional groups were loaded using magnetic attachments on the same day as implant placement or 3 months after surgery, respectively. All participants completed questionnaires (the Japanese version of the Oral Health Impact Profile for edentulous [OHIP-EDENT-J], the patient's denture assessment [PDA], and general satisfaction) before implant placement (baseline) and 1, 2, 3, 4, 5, 6, and 12 months after surgery. The median differences between baseline and each monthly score were compared using the Mann-Whitney U test. The differences in median and 95% confidence interval between two groups were analyzed. The immediate group showed slightly lower OHIP-EDENT-J summary score at 1 and 3 months than the conventional group (P=0.09). In the lower denture domain of PDA, the immediate group showed a statistically higher score at 3 months (P=0.04). There was no statistically significant difference in general satisfaction between the two groups. Based on this preliminary study, immediate loading of mandibular two-implant overdentures with magnetic attachments tends to improve oral health-related quality of life and patient assessment earlier than observed with a conventional loading protocol. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  16. Sources of variability in language development of children with cochlear implants: age at implantation, parental language, and early features of children's language construction.

    PubMed

    Szagun, Gisela; Schramm, Satyam A

    2016-05-01

    The aim of the present study was to analyze the relative influence of age at implantation, parental expansions, and child language internal factors on grammatical progress in children with cochlear implants (CI). Data analyses used two longitudinal corpora of spontaneous speech samples, one with twenty-two and one with twenty-six children, implanted between 0;6 and 3;10. Analyses were performed on the combined and separate samples. Regression analyses indicate that early child MLU is the strongest predictor of child MLU two and two-and-a-half years later, followed by parental expansions and age at implantation. Associations between earliest MLU gains and MLU two years later point to stability of individual differences. Early type and token frequencies of determiners predict MLU two years later more strongly than early frequency of lexical words. We conclude that features of CI children's very early language have considerable predictive value for later language outcomes.

  17. Finite Element Simulation of NiTi Umbrella-Shaped Implant Used on Femoral Head under Different Loadings.

    PubMed

    Mehrabi, Reza; Dorri, Milad; Elahinia, Mohammad

    2017-03-12

    In this study, an umbrella-shaped device that is used for osteonecrosis treatment is simulated. The femoral head is subjected to various complex loadings as a result of a person's daily movements. Implant devices used in the body are made of shape memory alloy materials because of their remarkable resistance to wear and corrosion, good biocompatibility, and variable mechanical properties. Since this NiTi umbrella-shaped implant is simultaneously under several loadings, a 3-D model of shape memory alloy is utilized to investigate the behavior of the implant under different conditions. Shape memory and pseudo-elasticity behavior of NiTi is analyzed using a numerical model. The simulation is performed within different temperatures and in an isothermal condition with varied and complex loadings. The objective of this study is to evaluate the performance of the device under thermal and multi-axial forces via numerically study. Under tensile loading, the most critical points are on the top part of the implant. It is also shown that changes in temperature have a minor effect on the Von Mises stress. Applied forces and torques have significant influence on the femoral head. Simulations results indicate that the top portion of the umbrella is under the most stress when embedded in the body. Consequently, the middle, curved portion of the umbrella is under the least amount of stress.

  18. Finite Element Simulation of NiTi Umbrella-Shaped Implant Used on Femoral Head under Different Loadings

    PubMed Central

    Mehrabi, Reza; Dorri, Milad; Elahinia, Mohammad

    2017-01-01

    In this study, an umbrella-shaped device that is used for osteonecrosis treatment is simulated. The femoral head is subjected to various complex loadings as a result of a person’s daily movements. Implant devices used in the body are made of shape memory alloy materials because of their remarkable resistance to wear and corrosion, good biocompatibility, and variable mechanical properties. Since this NiTi umbrella-shaped implant is simultaneously under several loadings, a 3-D model of shape memory alloy is utilized to investigate the behavior of the implant under different conditions. Shape memory and pseudo-elasticity behavior of NiTi is analyzed using a numerical model. The simulation is performed within different temperatures and in an isothermal condition with varied and complex loadings. The objective of this study is to evaluate the performance of the device under thermal and multi-axial forces via numerically study. Under tensile loading, the most critical points are on the top part of the implant. It is also shown that changes in temperature have a minor effect on the Von Mises stress. Applied forces and torques have significant influence on the femoral head. Simulations results indicate that the top portion of the umbrella is under the most stress when embedded in the body. Consequently, the middle, curved portion of the umbrella is under the least amount of stress. PMID:28952502

  19. [Local injection of exogenous nerve growth factor improves early bone maturation of implants].

    PubMed

    Yao, Yang; Du, Yu; Gu, Xia; Guang, Meng-Kai; Huang, Bo; Gong, Ping

    2018-04-01

    To investigate the effects of nerve growth factor (NGF) in the osteogenic action of implants and the maturation and reconstruction changes in bone tissues in the early stage of osseointegration. The mouse implant model was established by placing titanium in the femoral head of the mouse and locally injecting NGF in the implant zone. On 1, 2 and 4 weeks after operation, stain samples were collected from animals using hematoxylin-eosin (HE) staining and Masson staining. The effect of NGF on the bone maturation was compared at different time points of early stage osseointegration. The results of HE and Masson staining indicated that the local injection of external NGF can up-regulate bone mass, amount of bone trabecula, and bone maturity in the mouse model. The mature bone rate in treatment group of 1 week and 4 weeks after operation were significantly higher than those in the control group (P<0.05). NGF can shorten the period of bone maturation.

  20. Efficiency of Nanotube Surface-Treated Dental Implants Loaded with Doxycycline on Growth Reduction of Porphyromonas gingivalis.

    PubMed

    Ferreira, Cimara Fortes; Babu, Jegdish; Hamlekhan, Azhang; Patel, Sweetu; Shokuhfar, Tolou

    The prevalence of peri-implant infection in patients with dental implants has been shown to range from 28% to 56%. A nanotube-modified implant surface can deliver antibiotics locally and suppress periodontal pathogenic bacterial growth. The aim of this study was to evaluate the deliverability of antibiotics via a nanotube-modified implant. Dental implants with a nanotube surface were fabricated and loaded with doxycycline. Afterward, each dental implant with a nanotube surface was placed into 2-mL tubes, removed from solution, and placed in a fresh solution daily for 28 days. Experimental samples from 1, 2, 4, 16, 24, and 28 days were used for this evaluation. The concentration of doxycycline was measured using spectrophotometric analysis at 273-nm absorbance. The antibacterial effect of doxycycline was evaluated by supplementing Porphyromonas gingivalis (P gingivalis) growth media with the solution collected from the dental implants at the aforementioned time intervals for a period of 48 hours under anaerobic conditions. A bacterial viability assay was used to evaluate P gingivalis growth at 550-nm absorbance. Doxycycline concentration varied from 0.33 to 1.22 μg/mL from day 1 to day 28, respectively. A bacterial viability assay showed the highest P gingivalis growth at day 1 (2 nm) and the lowest at day 4 (0.17 nm), with a gradual reduction from day 1 to day 4 of approximately 87.5%. The subsequent growth pattern was maintained and slightly increased from baseline in approximately 48.3% from day 1 to day 24. The final P gingivalis growth measured at day 28 was 29.4% less than the baseline growth. P gingivalis growth was suppressed in media supplemented with solution collected from dental implants with a nanotube surface loaded with doxycycline during a 28-day time interval.

  1. Load transfer in the proximal tibia following implantation with a unicompartmental knee replacement: a static snapshot.

    PubMed

    Simpson, D J; Kendrick, B J L; Dodd, C A F; Price, A J; Gill, H S; Murray, D W

    2011-05-01

    Unicompartmental knee replacement (UKR) is an appealing alternative to total knee replacement when the patient has isolated medial compartment osteoarthritis. A common observation post-operatively is radiolucency between the tibial tray wall and the bone. In addition, some patients complain of persistent pain over the proximal tibia antero-medially; this may be related to elevated bone strains in the tibia. Currently, there is no intentionally made mechanical bond between the vertical wall of an Oxford UKR and the adjacent bone; whether one exists or not will influence the load transmission in the proximal tibia and may affect the elevated tibia strain. The aim of this study was to investigate how introducing a mechanical tie between the tibial tray wall and the adjacent bone might alter the load carried into the tibia for both cemented and cementless UKRs. Strain energy density in the region of bone adjacent to the tray wall was considerably increased when a mechanical tie was introduced; this has the potential of reducing the likelihood of a radiolucency occurring in that region. Moreover, a mechanical tie had the effect of reducing proximal tibia strain, which may decrease the incidence of pain following implantation with a UKR.

  2. Strains in trussed spine interbody fusion implants are modulated by load and design.

    PubMed

    Caffrey, Jason P; Alonso, Eloy; Masuda, Koichi; Hunt, Jessee P; Carmody, Cameron N; Ganey, Timothy M; Sah, Robert L

    2018-04-01

    Titanium cages with 3-D printed trussed open-space architectures may provide an opportunity to deliver targeted mechanical behavior in spine interbody fusion devices. The ability to control mechanical strain, at levels known to stimulate an osteogenic response, to the fusion site could lead to development of optimized therapeutic implants that improve clinical outcomes. In this study, cages of varying design (1.00 mm or 0.75 mm diameter struts) were mechanically characterized and compared for multiple compressive load magnitudes in order to determine what impact certain design variables had on localized strain. Each cage was instrumented with small fiducial sphere markers (88 total) at each strut vertex of the truss structure, which comprised of 260 individual struts. Cages were subjected to a 50 N control, 1000 N, or 2000 N compressive load between contoured loading platens in a simulated vertebral fusion condition, during which the cages were imaged using high-resolution micro-CT. The cage was analyzed as a mechanical truss structure, with each strut defined as the connection of two vertex fiducials. The deformation and strain of each strut was determined from 50 N control to 1000 N or 2000 N load by tracking the change in distance between each fiducial marker. As in a truss system, the number of struts in tension (positive strain) and compression (negative strain) were roughly equal, with increased loads resulting in a widened distribution (SD) compared with that at 50 N tare load indicating increased strain magnitudes. Strain distribution increased from 1000 N (+156 ± 415 με) to 2000 N (+180 ± 605 με) in 1.00 mm cages, which was similar to 0.75 mm cages (+132 ± 622 με) at 1000 N load. Strain amplitudes increased 42%, from 346με at 1000 N to 492με at 2000 N, for 1.00 mm cages. At 1000 N, strain amplitude in 0.75 mm cages (481με) was higher by 39% than that in 1.00 mm cages. These amplitudes

  3. The early days of the multi channel cochlear implant: efforts and achievement in France.

    PubMed

    Chouard, C H

    2015-04-01

    On September 10th 2013, the clinical medical research Lasker award winners were rewarded for their work on multichannel cochlear implant. It has been my pleasure to see that such a major topic had caught the attention of the Members of the Jury for this prestigious award. That is why I accepted an invitation to participate in a special issue of Hearing Research devoted to the three winners. Here I highlight four scientific contributions made by the French team in late 1970s and early 1980s to modern multichannel cochlear implant development. 1) Chouard and MacLeod plotted an approximate frequency map of the whole length of the human cochlea, including its "hidden face" corresponding to speech frequencies. Moreover MacLeod suggested a sequential display of electrical stimulation as a function of each electrode, a precursor to today's electrodogram and interleaved stimulation. 2) Chouard performed total cochlear implantation in a deaf adult male with 8 electrically independent electrodes that were evenly distributed along the cochlea. 3) Chouard and MacLeod described in a patent detailed sound signal processing for a functional multichannel cochlear implant and reported speech discrimination without help of lip reading in some totally deafened patients. 4) Chouard experimentally demonstrated in the guinea pig the advantage of early cochlear implantation in treating profound neonatal deafness. This article is part of a Special Issue entitled . Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Impact of early complications on outcomes in patients with implantable cardioverter-defibrillator for primary prevention.

    PubMed

    Ascoeta, Maria Soledad; Marijon, Eloi; Defaye, Pascal; Klug, Didier; Beganton, Frankie; Perier, Marie-Cécile; Gras, Daniel; Algalarrondo, Vincent; Deharo, Jean-Claude; Leclercq, Christophe; Fauchier, Laurent; Babuty, Dominique; Bordachar, Pierre; Sadoul, Nicolas; Boveda, Serge; Piot, Olivier

    2016-05-01

    The lifesaving benefit of implantable cardioverter-defibrillators (ICDs) has been demonstrated. Their use has increased considerably in the past decade, but related complications have become a major concern. The purpose of this study was to assess the incidence and effect on outcomes of early (≤30 days) complications after ICD implantation for primary prevention in a large French population. We analyzed data from 5539 patients from the multicenter French DAI-PP (Défibrillateur Automatique Implantable-Prévention Primaire) registry (2002-2012) who had coronary artery disease or dilated cardiomyopathy and were implanted with an ICD for primary prevention. Overall, early complications occurred in 707 patients (13.5%), mainly related to lead dislodgment or hematoma (57%). Independent factors associated with occurrence of early complications were severe renal impairment (odds ratio [OR] 1.66, 95% confidence interval [CI] 1.17-2.37, P = .02), age ≥75 years (OR 1.01, 95% CI 1.00-1.02, P = .03), cardiac resynchronization therapy (OR 1.58, 95% CI 1.16-2.17, P = .01), and anticoagulant therapy (OR 1.28, 95% CI 1.02-1.61, P = .03). During a mean ± SD follow-up of 3.1 ± 2.3 years, 824 (15.8%) patients experienced ≥1 late complication (>30 days), and 782 (14.9%) patients died. After adjustment, early complications remained associated with occurrence of late complications (OR 2.15, 95% CI 1.73-2.66, P < .0001) and mortality (OR 1.70, 95% CI 1.34-2.17, P = .003). Early complications are common after ICD implantation for primary prevention, occurring in 1 in 7 patients, and are associated with an increased risk of late complications and overall mortality. Further studies are needed to investigate the underlying mechanisms of such associations. Copyright © 2016 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

  5. Teicoplanin-loaded borate bioactive glass implants for treating chronic bone infection in a rabbit tibia osteomyelitis model.

    PubMed

    Zhang, Xin; Jia, Weitao; Gu, Yifei; Xiao, Wei; Liu, Xin; Wang, Deping; Zhang, Changqing; Huang, Wenhai; Rahaman, Mohamed N; Day, Delbert E; Zhou, Nai

    2010-08-01

    The treatment of chronic osteomyelitis (bone infection) remains a clinical challenge. In this work, pellets composed of a chitosan-bonded mixture of borate bioactive glass particles (<50microm) and teicoplanin powder (antibiotic), were evaluated in vitro and in vivo for treating chronic osteomyelitis induced by methicillin-resistant Staphylococcus aureus (MRSA) in a rabbit model. When immersed in phosphate-buffered saline, the pellets showed sustained release of teicoplanin over 20-30 days, while the bioactive glass converted to hydroxyapatite (HA) within 7 days, eventually forming a porous HA structure. Implantation of the teicoplanin-loaded pellets in a rabbit tibia osteomyelitis model resulted in the detection of teicoplanin in the blood for about 9 days. The implants converted to a bone-like HA graft, and supported the ingrowth of new bone into the tibia defects within 12 weeks of implantation. Microbiological, histological and scanning electron microscopy techniques showed that the implants provided a cure for the bone infection. The results indicate that the teicoplanin-loaded borate bioactive glass implant, combining sustained drug release with the ability to support new bone ingrowth, could provide a method for treating chronic osteomyelitis. Copyright 2010 Elsevier Ltd. All rights reserved.

  6. Calcium phosphate-titanium composites for articulating surfaces of load-bearing implants.

    PubMed

    Bandyopadhyay, Amit; Dittrick, Stanley; Gualtieri, Thomas; Wu, Jeffrey; Bose, Susmita

    2016-04-01

    Calcium phosphate (CaP)-titanium (Ti) composites were processed using a commercial laser engineered net shaping (LENS™) machine to increase wear resistance of articulating surfaces of load-bearing implants. Such composites could be used to cover the surface of titanium implants and potentially increase the lifetime of a joint replacement. It was hypothesized that adding calcium phosphate to commercially pure titanium (CP-Ti) and Ti6Al4V alloy via laser processing would decrease the material loss when subjected to wear. This added protection would be due to the in situ formation of a CaP tribofilm. Different amounts of CaP were mixed by weight with pure Ti and Ti6Al4V powders. The mixed powders were then made into cylindrical samples using a commercial LENS™-750 system. Microstructures were observed and it was found the CaP had integrated into the titanium metal matrix. Compression test revealed that CaP significantly increased the 0.2% offset yield strength as well as the ultimate compressive strength of CP-Ti. It was found that the addition of CaP to pure titanium reduced the material loss and increased wear resistance. This was due to the formation of CaP tribofilm on the articulating surface. The in situ formed tribofilm also lowered the coefficient of friction and acted as a solid lubricant between the two interacting metal surfaces. Overall, CaP addition to Ti and its alloy Ti6Al4V show an effective way to minimize wear induced damage due to the formation of in situ tribofilm at the articulating surface, a strategy that can be utilized in various biomedical devices. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Timing Discrepancies of Early Intervention Hearing Services in Urban and Rural Cochlear Implant Recipients

    PubMed Central

    Bush, Matthew L.; Burton, Mary; Loan, Ashley; Shinn, Jennifer B.

    2013-01-01

    Objective The purpose of this study was to examine the timing of early intervention diagnostic and therapeutic services in cochlear implant recipients from rural and urban areas. Study design Retrospective case series review Setting Tertiary referral center Patients Cochlear implant recipients from a single comprehensive hearing institute born with severe congenital sensorineural hearing loss were examined. Timing of diagnostic and therapeutic services was examined. Intervention(s) Diagnosis, amplification, and eventual cochlear implantation for all patients in the study Main outcome measure(s) Time points of definitive diagnosis, amplification, and cochlear implantation for children from urban and rural regions were examined. Correlation analysis of distance to testing center and timing of services was also assessed. Results 40 children born with congenital hearing loss were included in the study and were diagnosed at a median age of 13 weeks after birth. Children from rural regions obtained amplification at a median age of 47.7 weeks after birth, while urban children were amplified at 26 weeks after birth. Cochlear implantation was performed at a median age of 182 weeks after birth in those from rural areas and at 104 weeks after birth in urban-dwelling patients. A linear relationship was identified between distance to the implant center and timing of hearing aid amplification (r=0.5, p=0.033) and cochlear implantation (r=0.5, p=0.016). Conclusions Children residing outside of metro areas may be at higher risk of delayed rehabilitative services and cochlear implantation than those residing in urban areas that may be closer in proximity to tertiary care centers. PMID:24136305

  8. Enhanced antitumor efficacy of poly(D,L-lactide-co-glycolide)-based methotrexate-loaded implants on sarcoma 180 tumor-bearing mice

    PubMed Central

    Gao, Li; Xia, Lunyang; Zhang, Ruhui; Duan, Dandan; Liu, Xiuxiu; Xu, Jianjian; Luo, Lan

    2017-01-01

    Purpose Methotrexate is widely used in chemotherapy for a variety of malignancies. However, severe toxicity, poor pharmacokinetics, and narrow safety margin of methotrexate limit its clinical application. The aim of this study was to develop sustained-release methotrexate-loaded implants and evaluate antitumor activity of the implants after intratumoral implantation. Materials and methods We prepared the implants containing methotrexate, poly(D,L-lactide-co-glycolide), and polyethylene glycol 4000 with the melt-molding technique. The implants were characterized with regards to drug content, morphology, in vitro, and in vivo release profiles. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) were carried out to investigate the physicochemical properties of the implants. Furthermore, the antitumor activity of the implants was tested in a sarcoma 180 mouse model. Results The implants were prepared as solid rods. Scanning electron microscopy images showed a smooth surface of the implant, suggesting that methotrexate was homogeneously dispersed in the polymeric matrix. The results of DSC and FTIR indicated that no significant interaction between methotrexate and the polymer was observed in the implants. Both in vitro and in vivo release profiles of the implants were characterized by burst release followed by sustained release of methotrexate. Intratumoral implantation of methotrexate-loaded implants could efficiently delay tumor growth. Moreover, an increase in the dose of implants led to a higher tumor suppression rate without additional systemic toxicity. Conclusion These results demonstrate that methotrexate-loaded implants had significant antitumor efficacy in a sarcoma 180 mouse model without dose-limiting side effects, and suggest that the implants could be potentially applied as an intratumoral delivery system to treat cancer. PMID:29118572

  9. Analysis of load distribution in tooth-implant supported fixed partial dentures by the use of resilient abutment.

    PubMed

    Glisić, Mirko; Stamenković, Dragoslav; Grbović, Aleksandar; Todorović, Aleksandar; Marković, Aleksa; Trifković, Branka

    2016-01-01

    Differences between the tooth and implant response to load can lead to many biological and technical implications in the conditions of occlusal forces. The objective of this study was to analyze load distribution in tooth/implant-supported fixed partial dentures with the use of resilient TSA (Titan Shock Absorber, BoneCare GmbH, Augsburg, Germany) abutment and conventional non-resilient abutment using finite element method. This study presents two basic 3D models. For one model a standard non-resilient abutment is used, and on the implant of the second model a resilient TSA abutment is applied. The virtual model contains drawn contours of tooth, mucous membranes, implant, cortical bones and spongiosa, abutment and suprastructure. The experiment used 500 N of vertical force, applied in three different cases of axial load. Calculations of von Mises equivalent stresses of the tooth root and periodontium, implants and peri-implant tissue were made. For the model to which a non-resilient abutment is applied, maximum stress values in all three cases are observed in the cortical part of the bone (maximum stress value of 49.7 MPa). Measurements of stress and deformation in the bone tissue in the model with application of the resilientTSA abutment demonstrated similar distribution; however, these values are many times lower than in the model with non-resilient TSA abutment (maximum stress value of 28.9 MPa). Application of the resilient TSA abutment results in more equal distribution of stress and deformations in the bone tissue under vertical forces. These values are many times lower than in the model with the non-resilient abutment.

  10. Aesthetic outcome of single-tooth implant restorations following early implant placement and guided bone regeneration: crown and soft tissue dimensions compared with contralateral teeth.

    PubMed

    Cosyn, Jan; De Rouck, Tim

    2009-10-01

    The aim of this study was to compare crown and soft tissue dimensions of single-tooth implant restorations following early implant placement and guided bone regeneration (GBR) with contralateral non-restored teeth. Twenty-seven patients treated by one and the same surgeon and prosthodontist to restore a single-tooth gap with a class I bone defect in the premaxilla by means of an implant-supported restoration were reviewed. Patients were examined at least 6 months following placement of the crown. All implants had been inserted 6-8 weeks following tooth extraction in conjunction with GBR. At evaluation, crown dimensions, soft tissue dimensions, clinical conditions and patients' aesthetic satisfaction were assessed by one clinician who had not been involved in the treatment. Implant-supported crowns were not significantly longer than contralateral teeth and midfacial soft tissues showed comparable levels after on average 21 months of function. Our data also indicated significant papilla loss especially at the distal aspect of the implants. As the patient's aesthetic appreciation was favourable in 88% of the cases, this appeared to be of trivial importance. Favourable aesthetics may be achieved for single-tooth implant restorations following early implant placement and GBR. The impact of the latter on papilla levels, however, remains to be determined in longitudinal studies.

  11. In vitro and in vivo investigation of bisphosphonate-loaded hydroxyapatite particles for peri-implant bone augmentation.

    PubMed

    Kettenberger, Ulrike; Luginbuehl, Vera; Procter, Philip; Pioletti, Dominique P

    2017-07-01

    Locally applied bisphosphonates, such as zoledronate, have been shown in several studies to inhibit peri-implant bone resorption and recently to enhance peri-implant bone formation. Studies have also demonstrated positive effects of hydroxyapatite (HA) particles on peri-implant bone regeneration and an enhancement of the anti-resorptive effect of bisphosphonates in the presence of calcium. In the present study, both hydroxyapatite nanoparticles (nHA) and zoledronate were combined to achieve a strong reinforcing effect on peri-implant bone. The nHA-zoledronate combination was first investigated in vitro with a pre-osteoclastic cell assay (RAW 264.7) and then in vivo in a rat model of postmenopausal osteoporosis. The in vitro study confirmed that the inhibitory effect of zoledronate on murine osteoclast precursor cells was enhanced by loading the drug on nHA. For the in vivo investigation, either zoledronate-loaded or pure nHA were integrated in hyaluronic acid hydrogel. The gels were injected in screw holes that had been predrilled in rat femoral condyles before the insertion of miniature screws. Micro-CT-based dynamic histomorphometry and histology revealed an unexpected rapid mineralization of the hydrogel in vivo through formation of granules, which served as scaffold for new bone formation. The delivery of zoledronate-loaded nHA further inhibited a degradation of the mineralized hydrogel as well as a resorption of the peri-implant bone as effectively as unbound zoledronate. Hyaluronic acid with zoledronate-loaded nHA, thanks to its dual effect on inducing a rapid mineralization and preventing resorption, is a promising versatile material for bone repair and augmentation. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

  12. Clinical evaluation of satisfaction in patients rehabilitated with an immediately loaded implant-supported prosthesis: a controlled prospective study.

    PubMed

    Scala, Rudy; Cucchi, Alessandro; Ghensi, Paolo; Vartolo, Francesco

    2012-01-01

    The purpose of this controlled prospective study was to compare the satisfaction of patients rehabilitated with an immediately loaded implant-supported prosthesis and patients rehabilitated with a conventional denture in the mandible. Selected mandibular partially or totally edentulous patients were included in this prospective study. Patients' mandibles were completely rehabilitated with immediately loaded implants supporting a screw-retained full-arch prosthesis (test group) or with a conventional denture (control group). The Satisfaction Profile (SAT-P), which investigates a number of psychologic aspects related to the function and esthetics of the stomatognathic apparatus, was administered to each patient 1 month before and 3 months after provisional prosthetic rehabilitation. The questionnaire comprised four different SAT-P items: quality of eating, eating behavior, mood, and self-confidence. A visual analog scale was used to elicit patient responses. SAT-P item scores were analyzed statistically by means of the Student t test and the chi-square test (or the Mann-Whitney nonparametric test), with P < .05 considered significant. Forty-one patients were consecutively treated with 205 immediately loaded implants supporting a screw-retained full-arch prosthesis (test group); 38 patients were consecutively treated with a conventional denture (control group). Statistically significant differences were observed between the test and control groups for all four SAT-P items. The test group reported greater satisfaction for all items versus the control group. In both groups, the differences between pre- and postrehabilitation values were statistically significant. Each patient was satisfied with their treatment outcomes, but patients who received an implant-supported prosthesis were more satisfied than the patients who received a conventional denture. The results suggest that a screw-retained full-arch prosthesis on immediately loaded implants is a predictable means of

  13. A Radiographic Comparison of Progressive and Conventional Loading on Crestal Bone Loss and Density in Single Dental Implants: A Randomized Controlled Trial Study

    PubMed Central

    Ghoveizi, Rahab; Alikhasi, Marzieh; Siadat, Mohammad-Reza; Siadat, Hakimeh; Sorouri, Majid

    2013-01-01

    Objective: Crestal bone loss is a biological complication in implant dentistry. The aim of this study was to compare the effect of progressive and conventional loading on crestal bone height and bone density around single osseointegrated implants in the posterior maxilla by a longitudinal radiographic assessment technique. Materials and Methods: Twenty micro thread implants were placed in 10 patients (two implants per patient). One of the two implants in each patient was assigned to progressive and the other to conventional loading groups. Eight weeks after surgery, conventional implants were restored with a metal ceramic crown and the progressive group underwent a progressive loading protocol. The progressive loading group took different temporary acrylic crowns at 2, 4 and 6 months. After eight months, acrylic crowns were replaced with a metal ceramic crown. Computer radiography of both progressive and conventional implants was taken at 2, 4, 6, and 12 months. Image analysis was performed to measure the height of crestal bone loss and bone density. Results: The mean values of crestal bone loss at month 12 were 0.11 (0.19) mm for progressively and 0.36 (0.36) mm for conventionally loaded implants, with a statistically significant difference (P < 0.05) using Wilcoxon sign rank. Progressively loaded group showed a trend for higher bone density gain compared to the conventionally loaded group, but when tested with repeated measure ANOVA, the differences were not statistically significant (P > 0.05). Conclusion: The progressive group showed less crestal bone loss in single osseointegrated implant than the conventional group. Bone density around progressively loaded implants showed increase in crestal, middle and apical areas. PMID:23724215

  14. Mechanical torque measurement predicts load to implant cut-out: a biomechanical study investigating DHS anchorage in femoral heads.

    PubMed

    Suhm, Norbert; Hengg, Clemens; Schwyn, Ronald; Windolf, Markus; Quarz, Volker; Hänni, Markus

    2007-08-01

    Bone strength plays an important role in implant anchorage. Bone mineral density (BMD) is used as surrogate parameter to quantify bone strength and to predict implant anchorage. BMD can be measured by means of quantitative computer tomography (QCT) or dual energy X-ray absorptiometry (DXA). These noninvasive methods for BMD measurement are not available pre- or intra-operatively. Instead, the surgeon could determine bone strength by direct mechanical measurement. We have evaluated mechanical torque measurement for (A) its capability to quantify local bone strength and (B) its predictive value towards load at implant cut-out. Our experimental study was performed using sixteen paired human cadaver proximal femurs. BMD was determined for all specimens by QCT. The torque to breakaway of the cancellous bone structure (peak torque) was measured by means of a mechanical probe at the exact position of subsequent DHS placement. The fixation strength of the DHS achieved was assessed by cyclic loading in a stepwise protocol beginning with 1,500 N increasing 500 N every 5,000 cycles until 4,000 N. A highly significant correlation of peak torque with BMD (QCT) was found (r = 0.902, r (2) = 0.814, P < 0.001). Peak torque correlated highly significant with the load at implant cut-out (r = 0.795, P < 0.001). All specimens with a measured peak torque below 6.79 Nm failed at the first load level of 1,500 N. The specimens with a peak torque above 8.63 Nm survived until the last load level of 4,000 N. Mechanical peak torque measurement is able to quantify bone strength. In an experimental setup, peak torque identifies those specimens that are likely to fail at low load. In clinical routine, implant migration and cut-out depend on several parameters, which are difficult to control, such as fracture type, fracture reduction achieved, and implant position. The predictive value of peak torque towards cut-out in a clinical set-up therefore has to be carefully validated.

  15. High-strength, surface-porous polyether-ether-ketone for load-bearing orthopedic implants.

    PubMed

    Evans, Nathan T; Torstrick, F Brennan; Lee, Christopher S D; Dupont, Kenneth M; Safranski, David L; Chang, W Allen; Macedo, Annie E; Lin, Angela S P; Boothby, Jennifer M; Whittingslow, Daniel C; Carson, Robert A; Guldberg, Robert E; Gall, Ken

    2015-02-01

    Despite its widespread clinical use in load-bearing orthopedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface-porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer was 399.6±63.3 μm thick and possessed a mean pore size of 279.9±31.6 μm, strut spacing of 186.8±55.5 μm, porosity of 67.3±3.1% and interconnectivity of 99.9±0.1%. Monotonic tensile tests showed that PEEK-SP preserved 73.9% of the strength (71.06±2.17 MPa) and 73.4% of the elastic modulus (2.45±0.31 GPa) of as-received, injection-molded PEEK. PEEK-SP further demonstrated a fatigue strength of 60.0 MPa at one million cycles, preserving 73.4% of the fatigue resistance of injection-molded PEEK. Interfacial shear testing showed the pore layer shear strength to be 23.96±2.26 MPa. An osseointegration model in the rat revealed substantial bone formation within the pore layer at 6 and 12 weeks via microcomputed tomography and histological evaluation. Ingrown bone was more closely apposed to the pore wall and fibrous tissue growth was reduced in PEEK-SP when compared to non-porous PEEK controls. These results indicate that PEEK-SP could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopedic applications. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. High strength, surface porous polyether-ether-ketone for load-bearing orthopaedic implants

    PubMed Central

    Evans, Nathan T.; Torstrick, F. Brennan; Lee, Christopher S.D.; Dupont, Kenneth M.; Safranski, David L.; Chang, W. Allen; Macedo, Annie E.; Lin, Angela; Boothby, Jennifer M.; Whittingslow, Daniel C.; Carson, Robert A.; Guldberg, Robert E.; Gall, Ken

    2015-01-01

    Despite its widespread clinical use in load-bearing orthopaedic implants, polyether-ether-ketone (PEEK) is often associated with poor osseointegration. In this study, a surface porous PEEK material (PEEK-SP) was created using a melt extrusion technique. The porous layer thickness was 399.6±63.3 µm and possessed a mean pore size of 279.9±31.6 µm, strut spacing of 186.8±55.5 µm, porosity of 67.3±3.1%, and interconnectivity of 99.9±0.1%. Monotonic tensile tests showed that PEEK-SP preserved 73.9% of the strength (71.06±2.17 MPa) and 73.4% of the elastic modulus (2.45±0.31 GPa) of as-received, injection molded PEEK. PEEK-SP further demonstrated a fatigue strength of 60.0 MPa at one million cycles, preserving 73.4% of the fatigue resistance of injection molded PEEK. Interfacial shear testing showed the pore layer shear strength to be 23.96±2.26 MPa. An osseointegration model in the rat revealed substantial bone formation within the pore layer at 6 and 12 weeks via µCT and histological evaluation. Ingrown bone was more closely apposed to the pore wall and fibrous tissue growth was reduced in PEEK-SP when compared to non-porous PEEK controls. These results indicate that PEEK-SP could provide improved osseointegration while maintaining the structural integrity necessary for load-bearing orthopaedic applications. PMID:25463499

  17. Three-Dimensional Nonlinear Finite Element Analysis and Microcomputed Tomography Evaluation of Microgap Formation in a Dental Implant Under Oblique Loading.

    PubMed

    Jörn, Daniela; Kohorst, Philipp; Besdo, Silke; Borchers, Lothar; Stiesch, Meike

    2016-01-01

    Since bacterial leakage along the implant-abutment interface may be responsible for peri-implant infections, a realistic estimation of the interface gap width during function is important for risk assessment. The purpose of this study was to compare two methods for investigating microgap formation in a loaded dental implant, namely, microcomputed tomography (micro-CT) and three-dimensional (3D) nonlinear finite element analysis (FEA); additionally, stresses to be expected during loading were also evaluated by FEA. An implant-abutment complex was inspected for microgaps between the abutment and implant in a micro-CT scanner under an oblique load of 200 N. A numerical model of the situation was constructed; boundary conditions and external load were defined according to the experiment. The model was refined stepwise until its load-displacement behavior corresponded sufficiently to data from previous load experiments. FEA of the final, validated model was used to determine microgap widths. These were compared with the widths as measured in micro-CT inspection. Finally, stress distributions were evaluated in selected regions. No microgaps wider than 13 μm could be detected by micro-CT for the loaded implant. FEA revealed gap widths up to 10 μm between the implant and abutment at the side of load application. Furthermore, FEA predicted plastic deformation in a limited area at the implant collar. FEA proved to be an adequate method for studying microgap formation in dental implant-abutment complexes. FEA is not limited in gap width resolution as are radiologic techniques and can also provide insight into stress distributions within the loaded complex.

  18. Early healing of nanothickness bioceramic coatings on dental implants. An experimental study in dogs.

    PubMed

    Coelho, Paulo G; Cardaropoli, Giuseppe; Suzuki, Marcelo; Lemons, Jack E

    2009-02-01

    Thick bioceramic coatings like plasma sprayed hydroxyapatite have been shown to increase the overall tissue response and biomechanical fixation of dental implants. However, the presence and potential fracture of a bone-coating-metallic substrate interface at long times after implantation led these implants to fall from favor in clinical practice. The purpose of this study was to evaluate the biomechanical fixation and biological response of Ca- and P-based, 20-50 nm thickness bioceramic deposition on a previously alumina-blasted/acid-etched Ti-6Al-4V implant surface in a dog model. Cylindrical alumina-blasted/acid-etched (AB/AE) (Control, n = 16), and Nanothickness bioceramic coated AB/AE(Nano, n = 16) implant surfaces were surgically placed in dogs proximal tibia and remained for 2 and 4 weeks in vivo. Following euthanization, the implants-in-bone were mounted in epoxy and pullout at a 0.5 mm/min rate. Following mechanical testing, the specimens were decalcified and processed (Hematoxylin and Eosin) for standard transmitted light microscopy evaluation. Percent bone-to-implant contact (BIC) to the pulled out implant surface was determined through computer software. Statistical analyses were performed by one-way ANOVA at 95% level of significance and Tukey's post-hoc multiple comparisons. No significant differences in pullout force were observed (p > 0.88): 2W Control (212.08 +/- 42.96 N), 2W Nano (224.35 +/- 42.97 N), 4W Control (207.07 +/- 42.97 N), and 4W Nano (190.15 +/- 45.94 N). No significant differences in %BIC were observed (p > 0.94): 2W Control (72.66 +/- 8.51), 2W Nano (69.44 +/- 8.51), 4W Control (70.44 +/- 8.51), and 4W Nano (69.11 +/- 9.09). It is shown that 20-50 nm thickness bioceramic depositions onto previously alumina-blasted/acid-etched substrates did not improve the biomechanical fixation and the BIC at early implantation times, and studies concerning shorter and longer implantation times are recommended for confirmation or before a conclusion

  19. Evolution and acceptability of medical applications of RFID implants among early users of technology.

    PubMed

    Smith, Alan D

    2007-01-01

    RFID as a wireless identification technology that may be combined with microchip implants have tremendous potential in today's market. Although these implants have their advantages and disadvantages, recent improvements how allowed for implants designed for humans. Focus was given to the use of RFID tags and its effects on technology and CRM through a case study on VeriChip, the only corporation to hold the rights and the patent to the implantable chip for humans, and an empirically based study on working professionals to measure perceptions by early adopters of such technology. Through hypotheses-testing procedures, it was found that although some resistance to accept microchip implants was found in several applications, especially among gender, it was totally expected that healthcare and medical record keeping activities would be universally treated in a positive light and the use of authorities (namely governmental agencies) would be equally treated in a negative light by both sexes. Future trends and recommendations are presented along with statistical results collected through personal interviews.

  20. Adhesive strength of bone-implant interfaces and in-vivo degradation of PHB composites for load-bearing applications.

    PubMed

    Meischel, M; Eichler, J; Martinelli, E; Karr, U; Weigel, J; Schmöller, G; Tschegg, E K; Fischerauer, S; Weinberg, A M; Stanzl-Tschegg, S E

    2016-01-01

    Aim of this study was to evaluate the response of bone to novel biodegradable polymeric composite implants in the femora of growing rats. Longitudinal observation of bone reaction at the implant site (BV/TV) as well as resorption of the implanted pins were monitored using in vivo micro-focus computed tomography (µCT). After 12, 24 and 36 weeks femora containing the implants were explanted, scanned with high resolution ex vivo µCT, and the surface roughness of the implants was measured to conclude on the ingrowth capability for bone tissue. Scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) were used to observe changes on the surface of Polyhydroxybutyrate (PHB) during degradation and cell ingrowth. Four different composites with zirconium dioxide (ZrO2) and Herafill(®) were compared. After 36 weeks in vivo, none of the implants did show significant degradation. The PHB composite with ZrO2 and a high percentage (30%) of Herafill® as well as the Mg-alloy WZ21 showed the highest values of bone accumulation (increased BV/TV) around the implant. The lowest value was measured in PHB with 3% ZrO2 containing no Herafill®. Roughness measurements as well as EDX and SEM imaging could not reveal any changes on the PHB composites׳ surfaces. Biomechanical parameters, such as the adhesion strength between bone and implant were determined by measuring the shear strength as well as push-out energy of the bone-implant interface. The results showed that improvement of these mechanical properties of the studied PHBs P3Z, P3Z10H and P3Z30H is necessary in order to obtain appropriate load-bearing material. The moduli of elasticity, tensile strength and strain properties of the PHB composites are close to that of bone and thus promising. Compared to clinically used PLGA, PGA and PLA materials, their additional benefit is an unchanged local pH value during degradation, which makes them well tolerated by cells and immune system. They might be used

  1. Influence of surgical and prosthetic techniques on marginal bone loss around titanium implants. Part I: immediate loading in fresh extraction sockets.

    PubMed

    Berberi, Antoine N; Tehini, Georges E; Noujeim, Ziad F; Khairallah, Alexandre A; Abousehlib, Moustafa N; Salameh, Ziad A

    2014-10-01

    Delayed placement of implant abutments has been associated with peri-implant marginal bone loss; however, long-term results obtained by modifying surgical and prosthetic techniques after implant placement are still lacking. This study aimed to evaluate the marginal bone loss around titanium implants placed in fresh extraction sockets using two loading protocols after a 5-year follow-up period. A total of 36 patients received 40 titanium implants (Astra Tech) intended for single-tooth replacement. Implants were immediately placed into fresh extraction sockets using either a one-stage (immediate loading by placing an interim prosthesis into functional occlusion) or a two-stage prosthetic loading protocol (insertion of abutments after 8 weeks of healing time). Marginal bone levels relative to the implant reference point were evaluated at four time intervals using intraoral radiographs: at time of implant placement, and 1, 3, and 5 years after implant placement. Measurements were obtained from mesial and distal surfaces of each implant (α = 0.05). One-stage immediate implant placement into fresh extraction sockets resulted in a significant reduction in marginal bone loss (p < 0.002) compared to the traditional two-stage technique. Whereas mesial surfaces remained stable for the 5-year observation period, significant marginal bone loss was observed on distal surfaces of implants after cementation of interim prostheses (p < 0.007) and after 12 months (p < 0.034). Within the limitations of this study, immediate loading of implants placed into fresh extraction sockets reduced marginal bone loss and did not compromise the success rate of the restorations. © 2014 by the American College of Prosthodontists.

  2. Effect of macro-design of immediately loaded implants on micromotion and stress distribution in surrounding bone using finite element analysis.

    PubMed

    Fazel, Akbar; Aalai, Shima; Rismanchian, Mansour

    2009-08-01

    Macro-design influences the initial stability of implant and reduces micromotions. The aim of this study was to determine and compare micromotions and stress distribution in the bone around immediately loaded Maestro and Xive implants using finite element analysis. In this experimental study, accurate, clear photos were prepared of Xive and Maestro implants 12 and 13 mm long and 4 and 3.8 mm in diameter, respectively, using a Nikon Digital Camera with a resolution 5.24-megapixels with 8x Optical Zoom and 4x Digital Zoom. After accurate measurements, 3-D models of the implants inside the lower mandible (D2) were processed in Solidworks Version 2003 environment and transferred into Ansys for finite element analysis. After loading of 500 N angled at 70 degrees from the horizontal plane, the micromotion of the implant and Von Misses stresses around the bone were measured. The measured micromotion in Maestro implant was 148 mum and that in Xive was 284 mum. Stress distribution in the bone surrounding Maestro implant was better than Xive, but maximum stress surrounding Xive implants (30 MPa) was lower than Maestro (33 MPa). Based on the results obtained in the present study, maximum micromotion in maestro was less than that in Xive implants. This finding can guarantee the application of maestro implants for immediate loading.

  3. Word learning in deaf children with cochlear implants: effects of early auditory experience.

    PubMed

    Houston, Derek M; Stewart, Jessica; Moberly, Aaron; Hollich, George; Miyamoto, Richard T

    2012-05-01

    Word-learning skills were tested in normal-hearing 12- to 40-month-olds and in deaf 22- to 40-month-olds 12 to 18 months after cochlear implantation. Using the Intermodal Preferential Looking Paradigm (IPLP), children were tested for their ability to learn two novel-word/novel-object pairings. Normal-hearing children demonstrated learning on this task at approximately 18 months of age and older. For deaf children, performance on this task was significantly correlated with early auditory experience: Children whose cochlear implants were switched on by 14 months of age or who had relatively more hearing before implantation demonstrated learning in this task, but later implanted profoundly deaf children did not. Performance on this task also correlated with later measures of vocabulary size. Taken together, these findings suggest that early auditory experience facilitates word learning and that the IPLP may be useful for identifying children who may be at high risk for poor vocabulary development. © 2012 Blackwell Publishing Ltd.

  4. Word learning in deaf children with cochlear implants: effects of early auditory experience

    PubMed Central

    Houston, Derek M.; Stewart, Jessica; Moberly, Aaron; Hollich, George; Miyamoto, Richard T.

    2013-01-01

    Word-learning skills were tested in normal-hearing 12- to 40-month-olds and in deaf 22- to 40-month-olds 12 to 18 months after cochlear implantation. Using the Intermodal Preferential Looking Paradigm (IPLP), children were tested for their ability to learn two novel-word/novel-object pairings. Normal-hearing children demonstrated learning on this task at approximately 18 months of age and older. For deaf children, performance on this task was significantly correlated with early auditory experience: Children whose cochlear implants were switched on by 14 months of age or who had relatively more hearing before implantation demonstrated learning in this task, but later implanted profoundly deaf children did not. Performance on this task also correlated with later measures of vocabulary size. Taken together, these findings suggest that early auditory experience facilitates word learning and that the IPLP may be useful for identifying children who may be at high risk for poor vocabulary development. PMID:22490184

  5. Clinical and Radiographic Evaluation of Brånemark Implants with an Anodized Surface following Seven-to-Eight Years of Functional Loading

    PubMed Central

    Gelb, David; McAllister, Bradley; Nummikoski, Pirkka; Del Fabbro, Massimo

    2013-01-01

    The aim of this study was to evaluate the clinical and radiographic long-term outcomes of dental implants with an anodized TiUnite surface, placed in routine clinical practice. Two clinical centers participated in the study. One hundred and seven implants (80 in the maxilla and 27 in the mandible) in 52 patients were followed in the long term. Both one- and two-stage techniques were used for 38 and 69 implants, respectively. Thirty-eight single tooth restorations and 22 fixed partial prostheses were delivered, according to a delayed loading protocol, within 4 to 12 months since implant placement. All implants were stable at insertion and at the long-term follow-up visit, which occurred between 7 and 8 years of functional loading. The mean followup was 7.33 ± 0.47 years. The mean marginal bone level change at the long-term followup as compared to baseline was 1.49 ± 1.03 mm. No implant failure occurred. Healthy peri-implant mucosa was found around 95% of implants, whereas 91% of implants showed no visible plaque at the implant surfaces at the long-term followup. The study showed that dental implants with the TiUnite anodized surface demonstrate excellent long-term clinical and radiographic outcomes. PMID:23533412

  6. Characterization of wear debris from metal-on-metal hip implants during normal wear versus edge-loading conditions.

    PubMed

    Kovochich, Michael; Fung, Ernest S; Donovan, Ellen; Unice, Kenneth M; Paustenbach, Dennis J; Finley, Brent L

    2018-04-01

    Advantages of second-generation metal-on-metal (MoM) hip implants include low volumetric wear rates and the release of nanosized wear particles that are chemically inert and readily cleared from local tissue. In some patients, edge loading conditions occur, which result in higher volumetric wear. The objective of this study was to characterize the size, morphology, and chemistry of wear particles released from MoM hip implants during normal (40° angle) and edge-loading (65° angle with microseparation) conditions. The mean primary particle size by volume under normal wear was 35 nm (range: 9-152 nm) compared with 95 nm (range: 6-573 nm) under edge-loading conditions. Hydrodynamic diameter analysis by volume showed that particles from normal wear were in the nano- (<100 nm) to submicron (<1000 nm) size range, whereas edge-loading conditions generated particles that ranged from <100 nm up to 3000-6000 nm in size. Particles isolated from normal wear were primarily chromium (98.5%) and round to oval in shape. Edge-loading conditions generated more elongated particles (4.5%) (aspect ratio ≥ 2.5) and more CoCr alloy particles (9.3%) compared with normal wear conditions (1.3% CoCr particles). By total mass, edge-loading particles contained approximately 640-fold more cobalt than normal wear particles. Our findings suggest that high wear conditions are a potential risk factor for adverse local tissue effects in MoM patients who experience edge loading. This study is the first to characterize both the physical and chemical characteristics of MoM wear particles collected under normal and edge-loading conditions. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 986-996, 2018. © 2017 Wiley Periodicals, Inc.

  7. Biomechanics and load resistance of small-diameter and mini dental implants: a review of literature.

    PubMed

    Hasan, Istabrak; Bourauel, Christoph; Mundt, Torsten; Stark, Helmut; Heinemann, Friedhelm

    2014-02-01

    In recent years, the application of small-diameter and mini dental implants to support removable and fixed prosthesis has dramatically increased. However, the success of these implants under functional biting forces and the reaction of the bone around them need to be analyzed. This review was aimed to present studies that deal with the fatigue life of small-diameter and mini dental implants under normal biting force, and their survival rate. The numerical and experimental studies concluded that an increase in the risk of bone damage or implant failure may be assumed in critical clinical situations and implants with <3 mm diameter have a risk of fracture in clinical practice. The survival rate of the small-diameter and mini dental implants over 5 years was 98.3-99.4%.

  8. Genome Wide assessment of Early Osseointegration in Implant-Adherent Cells

    NASA Astrophysics Data System (ADS)

    Thalji, Ghadeer N.

    Objectives: To determine the molecular processes involved in osseointegration. Materials and methods: A structured literature review concerning in vitro and in vivo molecular assessment of osseointegration was performed. A rat and a human model were then used to identify the early molecular processes involved in osseointegration associated with a micro roughened and nanosurface superimposed featured implants. In the rat model, 32 titanium implants with surface topographies exhibiting a micro roughened (AT-II) and nanosurface superimposed featured implants (AT-I) were placed in the tibiae of 8 rats and subsequently harvested at 2 and 4 days after placement. Whereas in the human model, four titanium mini-implants with either a moderately roughened surface (TiOblast) or super-imposed nanoscale topography (Osseospeed) were placed in edentulous sites of eleven systemically healthy subjects and subsequently removed after 3 and 7 days. Total RNA was isolated from cells adherent to retrieved implants. A whole genome microarray using the Affymetrix 1.1 ST Array platform was used to describe the gene expression profiles that were differentially regulated by the implant surfaces. Results: The literature review provided evidence that particular topographic cues can be specifically integrated among the many extracellular signals received by the cell in its signal transduction network. In the rat model, functionally relevant categories related to ossification, skeletal system development, osteoblast differentiation, bone development and biomineral tissue development were upregulated and more prominent at AT-I compared to AT-II. In the human model, there were no significant differences when comparing the two-implant surfaces at each time point. However, the microarray identified several genes that were differentially regulated at day 7 vs. day 3 for both implant surfaces. Functionally relevant categories related to the extracellular matrix, collagen fibril organization and

  9. Evaluation of early bone response to fluoride-modified and anodically oxidized titanium implants through continuous removal torque analysis.

    PubMed

    Kwon, Taek-Ka; Lee, Hyo-Jung; Min, Seung-Ki; Yeo, In-Sung

    2012-10-01

    To compare between a bioactive and a bioinert implant with different geometries by continuous measurement of the removal torque and calculation of the angular momentum of each surfaced implant. Six New Zealand white rabbits were used in the study. Each rabbit received 2 implants. A bioactive fluoride-modified implant with a conical connection and microthread design was inserted into one tibia, and a bioinert anodically oxidized implant with an external connection design was inserted into the other. After 2 weeks of implant insertion, the removal torque values were continuously measured according to time. Using the time-torque curve resulting from the measurements, the maximum values were determined, and the angular momenta were calculated. The anodically oxidized implant had significantly higher peak removal torque and angular momentum values than the fluoride-modified implant (P < 0.05). The impact of the fluoride-modified bioactive implant on early bone response remains unclear. Considering the angular momentum of dental implants may assist in the elucidation of the effect of implant geometry on bone response.

  10. Survival rates and bone loss after immediate loading of implants in fresh extraction sockets (single gaps). A clinical prospective study with 4 year follow-up

    PubMed Central

    Wojtovicz, Eduardo; España-Lopez, Antonio; Jimenez-Guerra, Alvaro; Monsalve-Guil, Loreto; Ortiz-Garcia, Ivan; Serrera-Figallo, Maria-Angeles

    2018-01-01

    Background The aim of this prospective study was to report the outcome of treatment with implants inserted after tooth extraction and immediately loaded. Material and Methods Fifty-six patients with single tooth loss were treated with 116 IPX Galimplant® implants with internal connections and a sandblasted, acid-etched surface. All implants were placed after tooth extraction using a flapless approach without bone regeneration, and they were then immediately loaded with cemented acrylic prostheses. After a period of three months, definitive cemented ceramic prostheses were placed. Patients were examined throughout a total of 4 years of follow-up. Marginal bone loss and survival rates were evaluated using digital periapical radiographs, taking into account clinical variables such as age, gender, smoking, history of periodontitis, etiology of extraction, placement site, diameter, and implant length. The Mann-Whitney U and Kruskal-Wallis non-parametric tests were used to compare differences between subgroups created based on the different clinical variables identified. Results Clinical results indicate an implant survival and success rate of 97.4%. Three implants were lost. Of the 116 immediate acrylic single crowns initially placed, 113 were replaced with definitive ceramic crowns after 3 months. A total of 77.8% of implants were inserted in the maxilla, while 22.2% were inserted in the mandible. No further complications were reported after the follow-up period (4 years). The mean marginal bone loss was 0.67 mm ± 0.40 mm. No differences were found among the subgroups of study patients. Conclusions This study indicates that dental implants that are inserted after tooth extraction and immediately loaded may constitute a successful and predictable alternative implant treatment. Key words:Dental implants, post-extraction implants, fresh sockets, immediate loading, immediate prostheses, implant dentistry. PMID:29476669

  11. Immediate loading of mandibular overdentures supported by one-piece, direct metal laser sintering mini-implants: a short-term prospective clinical study.

    PubMed

    Mangano, Francesco G; Caprioglio, Alberto; Levrini, Luca; Farronato, Davide; Zecca, Piero A; Mangano, Carlo

    2015-02-01

    Only a few studies have dealt with immediately loaded, unsplinted mini-implants supporting ball attachment-retained mandibular overdentures (ODs). The aim of this study is to evaluate treatment outcomes of ball attachment-retained mandibular ODs supported by one-piece, unsplinted, immediately loaded, direct metal laser sintering (DMLS) mini-implants. Over a 4-year period (2009 to 2012), all patients referred to the Dental Clinic, University of Varese, and to a private practice for treatment with mandibular ODs were considered for inclusion in this study. Each patient received three or four DMLS mini-implants. Immediately after implant placement, a mandibular OD was connected to the implants. At each annual follow-up session, clinical and radiographic parameters were assessed, including the following outcome measures: 1) implant failures; 2) peri-implant marginal bone loss; and 3) complications. Statistical analysis was conducted using a life-table analysis. A total of 231 one-piece DMLS mini-implants were inserted in 62 patients. After 4 years of loading, six implants failed, giving an overall cumulative survival rate of 96.9%. The mean distance between the implant shoulder and the first visible bone-to-implant contact was 0.38 ± 0.25 and 0.62 ± 0.20 mm at the 1- and 4-year follow-up examinations, respectively. An incidence of 6.0% of biologic complications was reported; prosthetic complications were more frequent (12.9%). Within the limits of this study, it can be concluded that the immediate loading of one-piece, unsplinted, DMLS titanium mini-implants by means of ball attachment-supported mandibular ODs is a successful treatment procedure. Long-term follow-up studies are needed to confirm these results.

  12. Immediate occlusal loading of double acid-etched surface titanium implants in 41 consecutive full-arch cases in the mandible and maxilla: 6- to 74-month results.

    PubMed

    Ibañez, Juan C; Tahhan, Marcelo J; Zamar, Juan A; Menendez, Alicia B; Juaneda, Agustina M; Zamar, Nicolas J; Monqaut, Jose L

    2005-11-01

    The high success rate of dental implants has changed the quality of life for many patients. Immediate loading finds its application in some clinical cases and certainly adds another modality of treatment for the implant patient. Starting with a few implants immediately loaded with a bar overdenture in the mandible, the concept of immediate loading evolved to loading multiple implants in both the maxilla and mandible. In this investigation, 41 consecutive patients who needed full-arch restorations were treated with 343 double acid-etched surface implants between May 1998 and March 2004. The sample included smokers and bruxers. Twenty-three mandibular and 26 maxillary cases were treated, loading the implants within 48 hours, by using resin provisional prostheses, metal-reinforced provisional prostheses, or definitive prostheses (metal-acrylic or metal-ceramic). All implants were followed for 12 to 74 months. Follow-up consisted of clinical as well as radiographic examination. Furthermore, resonance frequency analysis was done in most of the implants during the last 2 years. The success rate obtained was 99.42% (only two mandibular implants that are still surviving were considered failures). The bone level was measured every year. The average radiographic bone level change was 0.56 mm at 12, 0.76 mm at 24, 0.84 mm at 36, 0.82 mm at 48, 0.83 mm at 60, and 0.94 mm at 72 months. A high success rate can be achieved when double acid-etched surface implants are immediately loaded with fixed full-arch restorations in the maxilla and mandible.

  13. Influence of artificial aging on the load-bearing capability of straight or angulated zirconia abutments in implant/tooth-supported fixed partial dentures.

    PubMed

    Nothdurft, Frank P; Doppler, Klaus E; Erdelt, Kurt J; Knauber, Andreas W; Pospiech, Peter R

    2010-01-01

    The aim of the study was to evaluate the influence of artificial aging on the fracture behavior of straight and angulated zirconia implant abutments used in ZirDesign (Astra Tech) implant/tooth-supported fixed partial dentures (FPDs) in the maxilla. Four different test groups (n = 8) representing anterior implant/tooth-supported FPDs were prepared. Groups 1 and 2 simulated a clinical situation with an ideal implant position (maxillary left central incisor) from a prosthetic point of view, which allowed for the use of a straight, prefabricated zirconia abutment. Groups 3 and 4 simulated a situation with a compromised implant position that required an angulated (20-degree) abutment. OsseoSpeed implants (4.5 3 13 mm, Astra Tech) as well as metal tooth analogs (maxillary right lateral incisor) with simulated periodontal mobility were mounted in polymethyl methacrylate. The FPDs (chromium-cobalt alloy) were cemented with glass ionomer. Groups 2 and 4 were thermomechanically loaded and subjected to static loading until failure. Statistical analysis of force data at the fracture site was performed using nonparametric tests. All samples survived thermomechanical loading. Artificial aging did not lead to a significant decrease in load-bearing capacity in either the straight abutments or the angulated abutments. The restorations that used angulated abutments exhibited higher fracture loads than the restorations with straight abutments (group 1: 209.13 ± 39.11 N; group 2: 233.63 ± 30.68 N; group 3: 324.62 ± 108.07 N; group 4: 361.75 ± 73.82 N). This difference in load-bearing performance was statistically significant, both with and without artificial aging. All abutment fractures occurred below the implant shoulder. Compensation for angulated implant positions with an angulated zirconia abutment is possible without reducing the load-bearing capacity of implant/tooth-supported anterior FPDs.

  14. Influence of the overall stiffness of a load-bearing porous titanium implant on bone ingrowth in critical-size mandibular bone defects in sheep.

    PubMed

    Schouman, T; Schmitt, M; Adam, C; Dubois, G; Rouch, P

    2016-06-01

    The aim of this work was to assess the influence of reduction of the apparent mechanical properties of fully load-bearing porous titanium implants used in mandibular bone defects. Segmental 18mm long bone defects were created bilaterally in the lower jaws of adult ewes. One group of 6 ewes (group A) was treated with load-bearing 'rigid' (high stiffness) porous implants on the right side, and with control on the left side. A second group of 6 ewes (group B) was treated with 'flexible' porous and control implants exhibiting apparent mechanical properties ten times lower than the rigid implants. The mechanical behavior of the reconstructed hemi-mandibles was assessed by cantilever testing and bone ingrowth into the segmental defects was assessed by BV/TV measurement within the implant using micro-CT 12 weeks after implantation. A significantly higher rigidity was identified for porous implants compared with control implants at the anterior interface in group B. BV/TV of porous implants was significantly higher than that of control implants in group A. BV/TV differences were significant between porous and control implants in group B and were homogeneous along the main axis. Significantly higher BV/TV was identified in most sub-volumes of group B porous implants compared with group A. This work highlights the critical importance of the tuning of scaffolds to promote bone ingrowth with reference to the local strains occurring within the porous scaffold, which in this application was achieved using fully load-bearing low-stiffness porous titanium implants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Clinical evaluation of immediate loading of electroeroded screw-retained titanium fixed prostheses supported by tilted implant: a multicenter retrospective study.

    PubMed

    Acocella, Alessandro; Ercoli, Carlo; Geminiani, Alessandro; Feng, Changyong; Billi, Mauro; Acocella, Gabriele; Giannini, Domenico; Sacco, Roberto

    2012-05-01

    Immediate occlusal loading of dental implants in the edentulous mandible has proven to be an effective, reliable, and predictable treatment protocol. However, there is limited long-term data available in the literature, when an electroeroded definitive cast-titanium fixed prosthesis is used for this treatment protocol. The aim of this study was to evaluate the clinical effectiveness of dental implants (Astra Tech Dental, Mölndal, Sweden) in the edentulous mandible immediately loaded with an electroeroded cast-titanium screw-retained fixed prosthesis. Forty-five patients received five implants each in the interforaminal area. All the implants were inserted with torque up to 40 Ncm and the distal implants were distally tilted approximately 20 to 30 degrees to minimize the length of posterior cantilevers. Implants were loaded within 48 hours of placement with an acrylic resin-titanium screw-retained prosthesis fabricated by electroerosion. Two of the 225 inserted implants failed after 3 and 16 months of healing, respectively, with a cumulative survival rate of 99.1% and a prosthetic survival rate of 97.8%. Immediate loading of tilted dental implants inserted in the edentulous mandible with a screw-retained titanium definitive prosthesis fabricated with electrical discharge machining provide reliable and predictable results. © 2011 Wiley Periodicals, Inc.

  16. In vivo evaluation of the anti-infection potential of gentamicin-loaded nanotubes on titania implants

    PubMed Central

    Yang, Ying; Ao, Hai-yong; Yang, Sheng-bing; Wang, Yu-gang; Lin, Wen-tao; Yu, Zhi-feng; Tang, Ting-ting

    2016-01-01

    Titanium-based implants have been widely used in orthopedic surgery; however, failures still occur. Our in vitro study has demonstrated that gentamicin-loaded, 80 nm-diameter nanotubes possessed both antibacterial and osteogenic activities. Thus, the aim of this study was to further investigate the in vivo anti-infection effect of the titanium implants with gentamicin-loaded nanotubes. Thirty-six male Sprague Dawley rats were used to establish an implant-associated infection model. A volume of 50 μL Staphylococcus aureus suspension (1×105 CFU/mL) was injected into the medullary cavity of the left femur, and then the titanium rods without modification (Ti), titanium nanotubes without drug loading (NT), and gentamicin-loaded titanium nanotubes (NT-G) were inserted with phosphate-buffered saline-inoculated Ti rods as a blank control. X-ray images were obtained 1 day, 21 days, and 42 days after surgery; micro-computed tomography, microbiological, and histopathological analyses were used to evaluate the infections at the time of sacrifice. Radiographic signs of bone infection, including osteolysis, periosteal reaction, osteosclerosis, and damaged articular surfaces, were demonstrated in the infected Ti group and were slightly alleviated in the NT group but not observed in the NT-G group. Meanwhile, the radiographic and gross bone pathological scores of the NT-G group were significantly lower than those of the infected Ti group (P<0.01). Explant cultures revealed significantly less bacterial growth in the NT-G group than in the Ti and NT groups (P<0.01), and the NT group showed decreased live bacterial growth compared with the Ti group (P<0.01). Confocal laser scanning microscopy, scanning electron microscopy, and histopathological observations further confirmed decreased bacterial burden in the NT-G group compared with the Ti and NT groups. We concluded that the NT-G coatings can significantly prevent the development of implant-associated infections in a rat model

  17. Semantic and syntactic reading comprehension strategies used by deaf children with early and late cochlear implantation.

    PubMed

    Gallego, Carlos; Martín-Aragoneses, M Teresa; López-Higes, Ramón; Pisón, Guzmán

    2016-01-01

    Deaf students have traditionally exhibited reading comprehension difficulties. In recent years, these comprehension problems have been partially offset through cochlear implantation (CI), and the subsequent improvement in spoken language skills. However, the use of cochlear implants has not managed to fully bridge the gap in language and reading between normally hearing (NH) and deaf children, as its efficacy depends on variables such as the age at implant. This study compared the reading comprehension of sentences in 19 children who received a cochlear implant before 24 months of age (early-CI) and 19 who received it after 24 months (late-CI) with a control group of 19 NH children. The task involved completing sentences in which the last word had been omitted. To complete each sentence children had to choose a word from among several alternatives that included one syntactic and two semantic foils in addition to the target word. The results showed that deaf children with late-CI performed this task significantly worse than NH children, while those with early-CI exhibited no significant differences with NH children, except under more demanding processing conditions (long sentences with infrequent target words). Further, the error analysis revealed a preference of deaf students with early-CI for selecting the syntactic foil over a semantic one, which suggests that they draw upon syntactic cues during sentence processing in the same way as NH children do. In contrast, deaf children with late-CI do not appear to use a syntactic strategy, but neither a semantic strategy based on the use of key words, as the literature suggests. Rather, the numerous errors of both kinds that the late-CI group made seem to indicate an inconsistent and erratic response when faced with a lack of comprehension. These findings are discussed in relation to differences in receptive vocabulary and short-term memory and their implications for sentence reading comprehension. Copyright © 2015

  18. A multicenter prospective study to assess the effect of early cleavage on embryo quality, implantation, and live-birth rate.

    PubMed

    de los Santos, Maria José; Arroyo, Gemma; Busquet, Ana; Calderón, Gloria; Cuadros, Jorge; Hurtado de Mendoza, Maria Victoria; Moragas, Marta; Herrer, Raquel; Ortiz, Agueda; Pons, Carme; Ten, Jorge; Vilches, Miguel Angel; Figueroa, Maria José

    2014-04-01

    To investigate the impact of early cleavage (EC) on embryo quality, implantation, and live-birth rates. Prospective cross-sectional study. Multicenter study. Seven hundred embryo transfers and 1,028 early-stage human embryos. None. Implantation according to the presence of EC and embryo quality. The presence of EC is associated with embryo quality, especially in cycles with autologous oocytes. However, the use of EC as an additional criterion for selecting an embryo for transfer does not appear to significantly improve likelihood of implantation. Furthermore, embryos that presented EC had live-birth rates per implanted embryo similar to those that did not show any sign of cleavage. At least for conventional embryo culture and morphologic evaluations, the additional evaluation of EC in embryos may not be valuable to improve embryo implantation. Copyright © 2014 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  19. Early Bimodal Stimulation Benefits Language Acquisition for Children With Cochlear Implants.

    PubMed

    Moberly, Aaron C; Lowenstein, Joanna H; Nittrouer, Susan

    2016-01-01

    Adding a low-frequency acoustic signal to the cochlear implant (CI) signal (i.e., bimodal stimulation) for a period of time early in life improves language acquisition. Children must acquire sensitivity to the phonemic units of language to develop most language-related skills, including expressive vocabulary, working memory, and reading. Acquiring sensitivity to phonemic structure depends largely on having refined spectral (frequency) representations available in the signal, which does not happen with CIs alone. Combining the low-frequency acoustic signal available through hearing aids with the CI signal can enhance signal quality. A period with this bimodal stimulation has been shown to improve language skills in very young children. This study examined whether these benefits persist into childhood. Data were examined for 48 children with CIs implanted under age 3 years, participating in a longitudinal study. All children wore hearing aids before receiving a CI, but upon receiving a first CI, 24 children had at least 1 year of bimodal stimulation (Bimodal group), and 24 children had only electric stimulation subsequent to implantation (CI-only group). Measures of phonemic awareness were obtained at second and fourth grades, along with measures of expressive vocabulary, working memory, and reading. Children in the Bimodal group generally performed better on measures of phonemic awareness, and that advantage was reflected in other language measures. Having even a brief period of time early in life with combined electric-acoustic input provides benefits to language learning into childhood, likely because of the enhancement in spectral representations provided.

  20. Immediate versus delayed loading of strategic mini dental implants for the stabilization of partial removable dental prostheses: a patient cluster randomized, parallel-group 3-year trial.

    PubMed

    Mundt, Torsten; Al Jaghsi, Ahmad; Schwahn, Bernd; Hilgert, Janina; Lucas, Christian; Biffar, Reiner; Schwahn, Christian; Heinemann, Friedhelm

    2016-07-30

    Acceptable short-term survival rates (>90 %) of mini-implants (diameter < 3.0 mm) are only documented for mandibular overdentures. Sound data for mini-implants as strategic abutments for a better retention of partial removable dental prosthesis (PRDP) are not available. The purpose of this study is to test the hypothesis that immediately loaded mini-implants show more bone loss and less success than strategic mini-implants with delayed loading. In this four-center (one university hospital, three dental practices in Germany), parallel-group, controlled clinical trial, which is cluster randomized on patient level, a total of 80 partially edentulous patients with unfavourable number and distribution of remaining abutment teeth in at least one jaw will receive supplementary min-implants to stabilize their PRDP. The mini-implant are either immediately loaded after implant placement (test group) or delayed after four months (control group). Follow-up of the patients will be performed for 36 months. The primary outcome is the radiographic bone level changes at implants. The secondary outcome is the implant success as a composite variable. Tertiary outcomes include clinical, subjective (quality of life, satisfaction, chewing ability) and dental or technical complications. Strategic implants under an existing PRDP are only documented for standard-diameter implants. Mini-implants could be a minimal invasive and low cost solution for this treatment modality. The trial is registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00007589 ( www.germanctr.de ) on January 13(th), 2015.

  1. In vivo evaluation of teicoplanin- and calcium sulfate-loaded PMMA bone cement in preventing implant-related osteomyelitis in rats.

    PubMed

    Tuzuner, T; Sencan, I; Ozdemir, D; Alper, M; Duman, S; Yavuz, T; Yildirim, M

    2006-12-01

    The objective of this study was to evaluate the efficacy of teicoplanin- and calcium sulphate-loaded polymethylmethacrylate (PMMA) bone cements in preventing experimental implant-related osteomyelitis in rats. Four groups of antibiotic-loaded rods were prepared and were implanted into the lateral condylus of the rat femur after inoculation of Staphylococcus aureus. The effectiveness of these were assessed microbiologically, radiographically, and histopathologically. Radiographic evaluation revealed a significant reduction of periostal reaction and osteolysis in rats that received calcium sulphate- and teicoplanin-loaded rods. Histopathological evaluation confirmed these results. Acute infection and bone necrosis were found to be significantly lower in rats that had received calcium sulphate- and teicoplanin-loaded rods. The addition of calcium sulfate to teicoplanin-loaded PMMA bone cement appeared satisfactory as an antibiotic-carrying system for prophylaxis of experimental implant-related osteomyelitis, but further investigations are needed to reach definitive statements for clinical applications.

  2. A 5-year comparison of marginal bone level following immediate loading of single-tooth implants placed in healed alveolar ridges and extraction sockets in the maxilla

    PubMed Central

    Berberi, Antoine N.; Sabbagh, Joseph M.; Aboushelib, Moustafa N.; Noujeim, Ziad F.; Salameh, Ziad A.

    2014-01-01

    Purpose: The aim of present investigation was to evaluate marginal bone level after 5-year follow-up of implants placed in healed ridges and fresh extraction sockets in maxilla with immediate loading protocol. Materials and Methods: Thirty-six patients in need of a single-tooth replacement in the anterior maxilla received 42 Astra Tech implants (Astra Tech Implant system™, Dentsply Implants, Mölndal, Sweden). Implants were placed either in healed ridges (group I) or immediately into fresh extraction sockets (group II). Implants were restored and placed into functional loading immediately by using a prefabricated abutment. Marginal bone level relative to the implant reference point was recorded at implant placement, crown cementation, 12, 36, and 60 months following loading using intra-oral radiographs. Measurements were made on the mesial and distal sides of each implant. Results: Overall, two implants were lost from the group II, before final crown cementation: they were excluded from the study. The mean change in marginal bone loss (MBL) after implant placement was 0.26 ± 0.161 mm for 1 year, and 0.26 ± 0.171 mm for 3 years, and 0.21 ± 0.185 mm for 5 years in extraction sockets and was 0.26 ± 0.176 mm for 1 year and 0.21 ± 0.175 mm for 3 years, and 0.19 ± 0.172 mm for 5 years in healed ridges group. Significant reduction of marginal bone was more pronounced in implants inserted in healed ridges (P < 0.041) compared to fresh surgical extraction sockets (P < 0.540). Significant MBL was observed on the mesial side of the implant after cementation of the provisional (P < 0.007) and after 12 months (P < 0.034) compared to the distal side which remained stable for 3 and 5 years observation period. Conclusions: Within the limitations of this study, responses of local bone to immediately loaded implants placed either in extraction sockets or healed ridges were similar. Functional loading technique by using prefabricated abutment placed during the surgery time

  3. A 5-year comparison of marginal bone level following immediate loading of single-tooth implants placed in healed alveolar ridges and extraction sockets in the maxilla.

    PubMed

    Berberi, Antoine N; Sabbagh, Joseph M; Aboushelib, Moustafa N; Noujeim, Ziad F; Salameh, Ziad A

    2014-01-01

    The aim of present investigation was to evaluate marginal bone level after 5-year follow-up of implants placed in healed ridges and fresh extraction sockets in maxilla with immediate loading protocol. Thirty-six patients in need of a single-tooth replacement in the anterior maxilla received 42 Astra Tech implants (Astra Tech Implant system™, Dentsply Implants, Mölndal, Sweden). Implants were placed either in healed ridges (group I) or immediately into fresh extraction sockets (group II). Implants were restored and placed into functional loading immediately by using a prefabricated abutment. Marginal bone level relative to the implant reference point was recorded at implant placement, crown cementation, 12, 36, and 60 months following loading using intra-oral radiographs. Measurements were made on the mesial and distal sides of each implant. Overall, two implants were lost from the group II, before final crown cementation: they were excluded from the study. The mean change in marginal bone loss (MBL) after implant placement was 0.26 ± 0.161 mm for 1 year, and 0.26 ± 0.171 mm for 3 years, and 0.21 ± 0.185 mm for 5 years in extraction sockets and was 0.26 ± 0.176 mm for 1 year and 0.21 ± 0.175 mm for 3 years, and 0.19 ± 0.172 mm for 5 years in healed ridges group. Significant reduction of marginal bone was more pronounced in implants inserted in healed ridges (P < 0.041) compared to fresh surgical extraction sockets (P < 0.540). Significant MBL was observed on the mesial side of the implant after cementation of the provisional (P < 0.007) and after 12 months (P < 0.034) compared to the distal side which remained stable for 3 and 5 years observation period. Within the limitations of this study, responses of local bone to immediately loaded implants placed either in extraction sockets or healed ridges were similar. Functional loading technique by using prefabricated abutment placed during the surgery time seems to maintain marginal bone around implant in both

  4. Optimization in multi-implant placement for immediate loading in edentulous arches using a modified surgical template and prototyping: a case report.

    PubMed

    Jayme, Sérgio J; Muglia, Valdir A; de Oliveira, Rafael R; Novaes, Arthur B Júnior

    2008-01-01

    Immediate loading of dental implants shortens the treatment time and makes it possible to give the patient an esthetic appearance throughout the treatment period. Placement of dental implants requires precise planning that accounts for anatomic limitations and restorative goals. Diagnosis can be made with the assistance of computerized tomographic scanning, but transfer of planning to the surgical field is limited. Recently, novel CAD/CAM techniques such as stereolithographic rapid prototyping have been developed to build surgical guides in an attempt to improve precision of implant placement. The aim of this case report was to show a modified surgical template used throughout implant placement as an alternative to a conventional surgical guide.

  5. Early Retinal and Choroidal Coat Thickness Changes After Intravitreal Dexamethasone Implant Injection for Diabetic Macular Edema.

    PubMed

    Horozoğlu, Fatih; Sever, Özkan

    2018-06-05

    Intravitreal steroid injection is one of the treatment choices in diabetic macular edema (DME). Dexamethasone (Dx) implant is the most novel form of intravitreal steroid therapy. Macular thickness improvement is well known effect of Dx implant however; subfoveal choroidal coat thickness (SFCT) changes need to be investigated. To evaluate the early central macular thickness (CMT) and SFCT alterations after single dose dexamethasone implant injection in DME. Retrospective cross-sectional study. We identified 29 patients with DME (29 eyes) who underwent optical coherence tomography (OCT) and fundus fluoroscein angiography (FFA). All patients received a single dose intravitreal Dx implant and were followed for CMT and SFCT alterations for the post-injection first hour, first day, first week, first month and third month. The preoperative mean CMT and SFCT measurements were 592.3±122.3 (412-879) μm and 264.8±53.7 (165-397) μm, respectively. CMT measurements significantly decreased from the first hour (p<0.050) and kept decreasing till 3 month (p<0.001); while SFCT decrement was just significant at the first day (p<0.05). When we compared the decrease in SFCT and CMT, 1 hour was similar, however not significant, 1.5% SFCT and 5% CMT decrease was, respectively (p>0.050). CMT decrease rate was significantly higher than SFCT at 1 day, 1 week, 1 month and 3 month (p<0.001). Intravitreal Dx implant has got a meaningful effect on CMT in patients with DME while SFCT decreases significantly at first hour and first day.

  6. A novel open-tray impression technique for fabrication of a provisional prosthesis on immediate load implants in a completely edentulous arch.

    PubMed

    Kaneko, Takahiro; Yamagishi, Kiyoshi; Horie, Norio; Shimoyama, Tetsuo

    2013-01-01

    To evaluate the clinical outcome of a novel open-tray impression technique for fabrication of a provisional prosthesis supported by immediately loaded implants in a completely edentulous arch. An open-tray impression technique was evaluated in this retrospective study that included patients treated between March 2006 and October 2009. Preoperatively, a diagnostic prosthesis was delivered, and a novel open tray was fabricated based on this prosthesis. After implant placement, the impression and interocclusal record were taken simultaneously using the novel open tray. Laboratory-fabricated, screw-retained, all-acrylic resin provisional restorations were delivered on the same day of surgery. The prosthesis was assessed from the day of surgery until replacement with a definitive prosthesis. The study included 21 patients (mean age, 64.5 years) and a total of 125 implants. Of these, 104 implants were immediately loaded. In all patients, well-fitting provisional restorations supported by a minimum of four implants were delivered. Fracture of the first molar cusp was observed in one case after 30 days. However, there was no extensive fracture in the framework or functional disorder of the prosthesis. No implant failed during the follow-up after implant surgery. This protocol enabled fabrication of a well-fitting acrylic resin provisional prosthesis supported by immediately loaded implants because the impression was taken while in centric occlusion and an occlusion identical to the diagnostic prosthesis could be reconstructed.

  7. Surgical factors in pediatric cochlear implantation and their early effects on electrode activation and functional outcomes.

    PubMed

    Francis, Howard W; Buchman, Craig A; Visaya, Jiovani M; Wang, Nae-Yuh; Zwolan, Teresa A; Fink, Nancy E; Niparko, John K

    2008-06-01

    To assess the impact of surgical factors on electrode status and early communication outcomes in young children in the first 2 years of cochlear implantation. Prospective multicenter cohort study. Six tertiary referral centers. Children 5 years or younger before implantation with normal nonverbal intelligence. Cochlear implant operations in 209 ears of 188 children. Percent active channels, auditory behavior as measured by the Infant Toddler Meaningful Auditory Integration Scale/Meaningful Auditory Integration Scale and Reynell receptive language scores. Stable insertion of the full electrode array was accomplished in 96.2% of ears. At least 75% of electrode channels were active in 88% of ears. Electrode deactivation had a significant negative effect on Infant Toddler Meaningful Auditory Integration Scale/Meaningful Auditory Integration Scale scores at 24 months but no effect on receptive language scores. Significantly fewer active electrodes were associated with a history of meningitis. Surgical complications requiring additional hospitalization and/or revision surgery occurred in 6.7% of patients but had no measurable effect on the development of auditory behavior within the first 2 years. Negative, although insignificant, associations were observed between the need for perioperative revision of the device and 1) the percent of active electrodes and 2) the receptive language level at 2-year follow-up. Activation of the entire electrode array is associated with better early auditory outcomes. Decrements in the number of active electrodes and lower gains of receptive language after manipulation of the newly implanted device were not statistically significant but may be clinically relevant, underscoring the importance of surgical technique and the effective placement of the electrode array.

  8. The molecular bacterial load assay replaces solid culture for measuring early bactericidal response to antituberculosis treatment.

    PubMed

    Honeyborne, Isobella; Mtafya, Bariki; Phillips, Patrick P J; Hoelscher, Michael; Ntinginya, Elias N; Kohlenberg, Anke; Rachow, Andrea; Rojas-Ponce, Gabriel; McHugh, Timothy D; Heinrich, Norbert

    2014-08-01

    We evaluated the use of the molecular bacterial load (MBL) assay, for measuring viable Mycobacterium tuberculosis in sputum, in comparison with solid agar and liquid culture. The MBL assay provides early information on the rate of decline in bacterial load and has technical advantages over culture in either form. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  9. Clinical and Radiographic Assessment of Three-Implant-Supported Fixed-Prosthesis Rehabilitation of the Edentulous Mandible: Immediate Versus Delayed Loading.

    PubMed

    Primo, Bruno Tochetto; Mezzari, Leonardo Marcos; da Fontoura Frasca, Luís Carlos; Linderman, Raquel; Rivaldo, Elken Gomes

    To evaluate and compare the clinical and radiographic outcomes of mandibular rehabilitation with fixed prostheses on three implants with immediate versus delayed loading. The sample comprised 21 patients who underwent treatment with immediate loading and 23 who received delayed loading. All had worn their prostheses for at least 18 months. Radiographic evaluation of bone loss was carried out in Adobe Photoshop CS5 by a single calibrated examiner using digitized panoramic radiographs. Clinical examination of the technical conditions of the prosthetic device assessed the condition of the acrylic resin base, dental occlusion, metal framework, presence of cover screws, screw fixation of the prosthesis and abutments, length of cantilever (effort) and resistance arms, presence of plaque on prosthetic abutments, and hygiene of the prosthesis. One implant failed in each group, resulting in a 95.23% treatment success rate with immediate loading and 95.65% with delayed loading (no statistically significant between-group difference). In the immediate-loading group, the mean bone loss was 1.96 ± 0.73 mm around central implants and 1.64 ± 0.84 mm at distal implants. In the delayed-loading group, the mean bone loss was 1.85 ± 0.67 mm around central implants and 1.70 ± 0.77 mm at distal implants. According to Student t test, there was no significant within-group difference in bone loss and no difference between the immediate-loading and delayed-loading groups. The only prosthesis-related complications that differed significantly between groups were "condition of the acrylic base," "occlusion," and "presence of right cover screw." There was no statistically significant association of lever arm ratio with peri-implant bone loss or bone loss on the mesial surfaces compared to the distal surfaces of the distal implants. The three-implant-supported fixed prosthesis protocol tested in this study proved to be a viable therapeutic strategy for mandibular edentulous patients with

  10. Sinus Floor Elevation with Modified Crestal Approach and Single Loaded Short Implants: A Case Report with 4 Years of Follow-Up

    PubMed Central

    Perelli, Michele; Abundo, Roberto; Corrente, Giuseppe; Saccone, Carlo

    2017-01-01

    Tooth extraction is usually followed by bone reduction. In the maxillary posterior region, this remodelling combined with sinus pneumatisation and periodontal defects may lead to a reduced basal bone height available for implant placement. Sinus floor elevation can be performed with different surgical techniques. Crestal approach has demonstrated to be effective, less invasive, and associated with a reduced morbidity. This article reports a modified sinus floor elevation by means of rotary, noncutting instruments, addition of xenograft, and 2 short-threaded implant placements. The aim of the study was to evaluate the implant's success and intrasinus radiographical bone gain after 4 years of functional loading. The premolar implant site presented a starting basal bone height of 6 mm, while the molar site was of 2 mm. In the first surgical step, sinus floor elevation was performed mesially and the implant was inserted, and distally only sinus floor elevation was performed. After 6 months, the mesial implant was uncovered and the second implant was inserted; 4 months later, the second fixture was uncovered, and both fixtures were loaded with single provisional screw-retained crowns and later with single screw-retained porcelain fused to metal crowns. Implants integrated successfully, and crestal bone remodelling did not exceed the smooth collar. Bone gain was 3 mm for the mesial implant and more than 5 mm for the distal one. PMID:29403665

  11. Sinus Floor Elevation with Modified Crestal Approach and Single Loaded Short Implants: A Case Report with 4 Years of Follow-Up.

    PubMed

    Perelli, Michele; Abundo, Roberto; Corrente, Giuseppe; Saccone, Carlo; Arduino, Paolo G

    2017-01-01

    Tooth extraction is usually followed by bone reduction. In the maxillary posterior region, this remodelling combined with sinus pneumatisation and periodontal defects may lead to a reduced basal bone height available for implant placement. Sinus floor elevation can be performed with different surgical techniques. Crestal approach has demonstrated to be effective, less invasive, and associated with a reduced morbidity. This article reports a modified sinus floor elevation by means of rotary, noncutting instruments, addition of xenograft, and 2 short-threaded implant placements. The aim of the study was to evaluate the implant's success and intrasinus radiographical bone gain after 4 years of functional loading. The premolar implant site presented a starting basal bone height of 6 mm, while the molar site was of 2 mm. In the first surgical step, sinus floor elevation was performed mesially and the implant was inserted, and distally only sinus floor elevation was performed. After 6 months, the mesial implant was uncovered and the second implant was inserted; 4 months later, the second fixture was uncovered, and both fixtures were loaded with single provisional screw-retained crowns and later with single screw-retained porcelain fused to metal crowns. Implants integrated successfully, and crestal bone remodelling did not exceed the smooth collar. Bone gain was 3 mm for the mesial implant and more than 5 mm for the distal one.

  12. Early fixation of cobalt-chromium based alloy surgical implants to bone using a tissue-engineering approach.

    PubMed

    Ogawa, Munehiro; Tohma, Yasuaki; Ohgushi, Hajime; Takakura, Yoshinori; Tanaka, Yasuhito

    2012-01-01

    To establish the methods of demonstrating early fixation of metal implants to bone, one side of a Cobalt-Chromium (CoCr) based alloy implant surface was seeded with rabbit marrow mesenchymal cells and the other side was left unseeded. The mesenchymal cells were further cultured in the presence of ascorbic acid, β-glycerophosphate and dexamethasone, resulting in the appearance of osteoblasts and bone matrix on the implant surface. Thus, we succeeded in generating tissue-engineered bone on one side of the CoCr implant. The CoCr implants were then implanted in rabbit bone defects. Three weeks after the implantation, evaluations of mechanical test, undecalcified histological section and electron microscope analysis were performed. Histological and electron microscope images of the tissue engineered surface exhibited abundant new bone formation. However, newly formed bone tissue was difficult to detect on the side without cell seeding. In the mechanical test, the mean values of pull-out forces were 77.15 N and 44.94 N for the tissue-engineered and non-cell-seeded surfaces, respectively. These findings indicate early bone fixation of the tissue-engineered CoCr surface just three weeks after implantation.

  13. Early Fixation of Cobalt-Chromium Based Alloy Surgical Implants to Bone Using a Tissue-engineering Approach

    PubMed Central

    Ogawa, Munehiro; Tohma, Yasuaki; Ohgushi, Hajime; Takakura, Yoshinori; Tanaka, Yasuhito

    2012-01-01

    To establish the methods of demonstrating early fixation of metal implants to bone, one side of a Cobalt-Chromium (CoCr) based alloy implant surface was seeded with rabbit marrow mesenchymal cells and the other side was left unseeded. The mesenchymal cells were further cultured in the presence of ascorbic acid, β-glycerophosphate and dexamethasone, resulting in the appearance of osteoblasts and bone matrix on the implant surface. Thus, we succeeded in generating tissue-engineered bone on one side of the CoCr implant. The CoCr implants were then implanted in rabbit bone defects. Three weeks after the implantation, evaluations of mechanical test, undecalcified histological section and electron microscope analysis were performed. Histological and electron microscope images of the tissue engineered surface exhibited abundant new bone formation. However, newly formed bone tissue was difficult to detect on the side without cell seeding. In the mechanical test, the mean values of pull-out forces were 77.15 N and 44.94 N for the tissue-engineered and non-cell-seeded surfaces, respectively. These findings indicate early bone fixation of the tissue-engineered CoCr surface just three weeks after implantation. PMID:22754313

  14. Visualization of early post-implantation mouse embryogenesis using 3D imaging modality (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Hsu, Chih-Wei; Le, Henry H.; Li-Villarreal, Nanbing; Piazza, Victor G.; Kalaga, Sowmya; Dickinson, Mary E.

    2017-02-01

    Hemodynamic force is vital to cardiovascular remodeling in the early post-implantation mouse embryo. Here, we present work using microCT and lightsheet microscopy to establish the critical sequence of developmental events required for forming functional vasculature and circulation in the embryo, yolk sac, and placenta in the context of normal and impaired flow. A flow impaired model, Mlc2a+/- will be used to determine how hemodynamic force affects the specific events during embryonic development and vascular remodeling between the 4 and 29-somite stage using microCT. We have recently established high-resolution methods for the generation of 3D image volumes from the whole embryo within the deciduum (Hsu et al., in revision). This method enables the careful characterization of 3D images of vitelline and umbilical vessel remodeling to define how poor blood flow impacts both vitelline and umbilical vessel remodeling. Novel lightsheet live imaging techniques will be used to determine the consequence of impaired blood flow on yolk sac vasculature remodeling and formation of umbilical vessels using transgenic reporters: Flk-myr::mCherry, Flk1-H2B::YFP, or ɛGlobin-GFP. High-resolution 3D imaging of fixed and ScaleA2-cleared whole mount embryos labeled with Ki67 and Caspase3 will also be performed using lightsheet microscopy to quantify the proliferation and apoptotic indexes of early post-implanted embryos and yolk sac. This multi-modality approach is aimed at revealing further information about the cellular mechanisms required for proper vessel remodeling and the initial stages in placentation during early post-implantation development.

  15. 3D perfusion bioreactor-activated porous granules on implant fixation and early bone formation in sheep.

    PubMed

    Ding, Ming; Henriksen, Susan S; Martinetti, Roberta; Overgaard, Søren

    2017-11-01

    Early fixation of total joint arthroplasties is crucial for ensuring implant survival. An alternative bone graft material in revision surgery is needed to replace the current gold standard, allograft, seeing that the latter is associated with several disadvantages. The incubation of such a construct in a perfusion bioreactor has been shown to produce viable bone graft materials. This study aimed at producing larger amounts of viable bone graft material (hydroxyapatite 70% and β-tricalcium-phosphate 30%) in a novel perfusion bioreactor. The abilities of the bioreactor-activated graft material to induce early implant fixation were tested in a bilateral implant defect model in sheep, with allograft as the control group. Defects were bilaterally created in the distal femurs of the animals, and titanium implants were inserted. The concentric gaps around the implants were randomly filled with either allograft, granules, granules with bone marrow aspirate or bioreactor-activated graft material. Following an observation time of 6 weeks, early implant fixation and bone formation were assessed by micro-CT scanning, mechanical testing, and histomorphometry. Bone formations were seen in all groups, while no significant differences between groups were found regarding early implant fixation. The microarchitecture of the bone formed by the synthetic graft materials resembled that of allograft. Histomorphometry revealed that allograft induced significantly more bone and less fibrous tissue (p < 0.05). In conclusion, bone formation was observed in all groups, while the bioreactor-activated graft material did not reveal additional effects on early implant fixation comparable to allograft in this model. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2465-2476, 2017. © 2016 Wiley Periodicals, Inc.

  16. Auditory maturation in premature infants: a potential pitfall for early cochlear implantation.

    PubMed

    Hof, Janny R; Stokroos, Robert J; Wix, Eduard; Chenault, Mickey; Gelders, Els; Brokx, Jan

    2013-08-01

    To describe spontaneous hearing improvement in the first years of life of a number of preterm neonates relative to cochlear implant candidacy. Retrospective case study. Hearing levels of 14 preterm neonates (mean gestational age at birth = 29 weeks) referred after newborn hearing screening were evaluated. Initial hearing thresholds ranged from 40 to 105 dBHL (mean = 85 dBHL). Hearing level improved to normal levels for four neonates and to moderate levels for five, whereas for five neonates, no improvement in hearing thresholds was observed and cochlear implantation was recommended. Three of the four neonates in whom the hearing improved to normal levels were born prior to 28 weeks gestational age. Hearing improvement was mainly observed prior to a gestational age of 80 weeks. Delayed maturation of an immature auditory pathway might be an important reason for referral after newborn hearing screening in premature infants. Caution is advised regarding early cochlear implantation in preterm born infants. Audiological follow-ups until at least 80 weeks gestational age are therefore recommended. © 2013 The American Laryngological, Rhinological and Otological Society, Inc.

  17. Persistent Language Delay Versus Late Language Emergence in Children With Early Cochlear Implantation

    PubMed Central

    Nicholas, Johanna; Tobey, Emily; Davidson, Lisa

    2016-01-01

    Purpose The purpose of the present investigation is to differentiate children using cochlear implants (CIs) who did or did not achieve age-appropriate language scores by midelementary grades and to identify risk factors for persistent language delay following early cochlear implantation. Materials and Method Children receiving unilateral CIs at young ages (12–38 months) were tested longitudinally and classified with normal language emergence (n = 19), late language emergence (n = 22), or persistent language delay (n = 19) on the basis of their test scores at 4.5 and 10.5 years of age. Relative effects of demographic, audiological, linguistic, and academic characteristics on language emergence were determined. Results Age at CI was associated with normal language emergence but did not differentiate late emergence from persistent delay. Children with persistent delay were more likely to use left-ear implants and older speech processor technology. They experienced higher aided thresholds and lower speech perception scores. Persistent delay was foreshadowed by low morphosyntactic and phonological diversity in preschool. Logistic regression analysis predicted normal language emergence with 84% accuracy and persistent language delay with 74% accuracy. Conclusion CI characteristics had a strong effect on persistent versus resolving language delay, suggesting that right-ear (or bilateral) devices, technology upgrades, and improved audibility may positively influence long-term language outcomes. PMID:26501740

  18. Development of Environmental Load Estimation Model for Road Drainage Systems in the Early Design Phase

    NASA Astrophysics Data System (ADS)

    Park, Jin-Young; Lee, Dong-Eun; Kim, Byung-Soo

    2017-10-01

    Due to the increasing concern about climate change, efforts to reduce environmental load are continuously being made in construction industry, and LCA (life cycle assessment) is being presented as an effective method to assess environmental load. Since LCA requires information on construction quantity used for environmental load estimation, however, it is not being utilized in the environmental review in the early design phase where it is difficult to obtain such information. In this study, computation system for construction quantity based on standard cross section of road drainage facilities was developed to compute construction quantity required for LCA using only information available in the early design phase to develop and verify the effectiveness of a model that can perform environmental load estimation. The result showed that it is an effective model that can be used in the early design phase as it revealed a 13.39% mean absolute error rate.

  19. Early Postimplant Speech Perception and Language Skills Predict Long-Term Language and Neurocognitive Outcomes Following Pediatric Cochlear Implantation

    ERIC Educational Resources Information Center

    Hunter, Cynthia R.; Kronenberger, William G.; Castellanos, Irina; Pisoni, David B.

    2017-01-01

    Purpose: We sought to determine whether speech perception and language skills measured early after cochlear implantation in children who are deaf, and early postimplant growth in speech perception and language skills, predict long-term speech perception, language, and neurocognitive outcomes. Method: Thirty-six long-term users of cochlear…

  20. Botulinum Toxin Type A as Preoperative Treatment for Immediately Loaded Dental Implants Placed in Fresh Extraction Sockets for Full-Arch Restoration of Patients With Bruxism.

    PubMed

    Mijiritsky, Eitan; Mortellaro, Carmen; Rudberg, Omri; Fahn, Miri; Basegmez, Cansu; Levin, Liran

    2016-05-01

    The aim of the present report was to describe the use of Botulinum toxin type A as preoperative treatment for immediately loaded dental implants placed in fresh extraction sockets for full-arch restoration of patients with bruxism. Patients with bruxism who were scheduled to receive immediately loaded full-arch implant supported fixed restorations were included in this retrospective clinical report. To reduce the occlusal forces applied in patients with bruxism, Botulinum toxin type A was introduced prior to the implant placement procedure. Patients were followed and implant survival as well as peri-implant bone level was assessed in each periodic follow-up visit. Adverse effects were also recorded. A control group with no use of Botulinum toxin was evaluated as well. A total of 26 patients (13 test and 13 control), with bruxism, aged 59.15 ± 11.43 years on average were included in this retrospective report and received immediately loaded dental implants placed in fresh extraction sockets for full-arch restoration. The test group treatment preceded by Botulinum toxin type A injection. Maxillary arches were supported by 8 to 10 implants while the mandibular arch was supported by 6 implants. All surgeries went uneventfully and no adverse effects were observed. The average follow-up time was 32.5 ± 10.4 months (range, 18-51). In the test group, no implant failures were recorded. One patient presented with 1 to 2 mm bone loss around 4 of the implants; the other implants presented with stable bone level. In the control group 1 patient lost 2 implants and another demonstrated 2 mm bone loss around 3 of the implants. The preoperative use of Botulinum toxin in patients with bruxism undergoing full-arch rehabilitation using immediately loaded dental implants placed in fresh extraction sockets seems to be a technique that deserves attention. Further long-term, large-scale randomized clinical trials will help to determine the additional benefit of this suggested

  1. Hypertensive phase and early complications after Ahmed glaucoma valve implantation with intraoperative subtenon triamcinolone acetonide.

    PubMed

    Turalba, Angela V; Pasquale, Louis R

    2014-01-01

    To evaluate intraoperative subtenon triamcinolone acetonide (TA) as an adjunct to Ahmed glaucoma valve (AGV) implantation. Retrospective comparative case series. Forty-two consecutive cases of uncontrolled glaucoma undergoing AGV implantation: 19 eyes receiving intraoperative subtenon TA and 23 eyes that did not receive TA. A retrospective chart review was performed on consecutive pseudophakic adult patients with uncontrolled glaucoma undergoing AGV with and without intraoperative subtenon TA injection by a single surgeon. Clinical data were collected from 42 eyes and analyzed for the first 6 months after surgery. Primary outcomes included intraocular pressure (IOP) and number of glaucoma medications prior to and after AGV implantation. The hypertensive phase (HP) was defined as an IOP measurement of greater than 21 mmHg (with or without medications) during the 6-month postoperative period that was not a result of tube obstruction, retraction, or malfunction. Postoperative complications and visual acuity were analyzed as secondary outcome measures. Five out of 19 (26%) TA cases and 12 out of 23 (52%) non-TA cases developed the HP (P=0.027). Mean IOP (14.2±4.6 in TA cases versus [vs] 14.7±5.0 mmHg in non-TA cases; P=0.78), and number of glaucoma medications needed (1.8±1.3 in TA cases vs 1.6±1.1 in the comparison group; P=0.65) were similar between both groups at 6 months. Although rates of serious complications did not differ between the groups (13% in the TA group vs 16% in the non-TA group), early tube erosion (n=1) and bacterial endophthalmitis (n=1) were noted with TA but not in the non-TA group. Subtenon TA injection during AGV implantation may decrease the occurrence of the HP but does not alter the ultimate IOP outcome and may pose increased risk of serious complications within the first 6 months of surgery.

  2. Loss of Bmal1 decreases oocyte fertilization, early embryo development and implantation potential in female mice.

    PubMed

    Xu, Jian; Li, Yan; Wang, Yizi; Xu, Yanwen; Zhou, Canquan

    2016-10-01

    Biological clock genes expressed in reproductive tissues play important roles in maintaining the normal functions of reproductive system. However, disruption of female circadian rhythm on oocyte fertilization, preimplantation embryo development and blastocyst implantation potential is still unclear. In this study, ovulation, in vivo and in vitro oocyte fertilization, embryo development, implantation and intracellular reactive oxygen species (ROS) levels in ovary and oviduct were studied in female Bmal1+/+ and Bmal1-/- mice. The number of naturally ovulated oocyte in Bmal1-/- mice decreased (5.2 ± 0.8 vs 7.8 ± 0.8, P < 0.001), with an increasing abnormal oocyte ratio (20.4 ± 3.5 vs 11.7 ± 2.0%, P = 0.001) after superovulation. Significantly lower fertilization rate and obtained blastocyst number were observed in Bmal1-/- female mice either mated with wild-type in vivo or fertilized by sperm from wild-type male mice in vitro (all P < 0.05). Interestingly, in vitro fertilization rate of oocytes derived from Bmal1-/- increased significantly compared with in vivo study (P < 0.01). After transferring blastocysts derived from Bmal1+/+ and Bmal1-/- female mice to pseudopregnant mice, the implantation sites of the latter decreased 5 days later (8.0 ± 0.8 vs 5.3 ± 1.0, P = 0.005). The intracellular ROS levels in the ovary on proestrus day and in the oviduct on metestrus day increased significantly in Bmal1-/- mice compared with that of Bmal1+/+ mice. Deletion of the core biological clock gene Bmal1 significantly decreases oocyte fertilization rate, early embryo development and implantation potential in female mice, and these may be possibly caused by excess ROS levels generated in ovary and oviduct.

  3. The Effect of Non-Infectious Wound Complications after Mastectomy on Subsequent Surgical Procedures and Early Implant Loss

    PubMed Central

    Nickel, Katelin B; Fox, Ida K; Margenthaler, Julie A; Wallace, Anna E; Fraser, Victoria J; Olsen, Margaret A

    2016-01-01

    Background Non-infectious wound complications (NIWCs) following mastectomy are not routinely tracked and data are generally limited to single-center studies. Our objective was to determine the rates of NIWCs among women undergoing mastectomy and assess the impact of immediate reconstruction (IR). Study Design We established a retrospective cohort using commercial claims data of women aged 18–64 years with procedure codes for mastectomy from 1/2004–12/2011. NIWCs within 180 days after operation were identified by ICD-9-CM diagnosis codes and rates were compared among mastectomy with and without autologous flap and/or implant IR. Results 18,696 procedures (10,836 [58%] with IR) among 18,085 women were identified. The overall NIWC rate was 9.2% (1,714/18,696); 56% required surgical treatment. The NIWC rates were 5.8% (455/7,860) after mastectomy-only, 10.3% (843/8,217) after mastectomy + implant, 17.4% (337/1,942) after mastectomy + flap, and 11.7% (79/677) after mastectomy + flap and implant (p<0.001). The rates of individual NIWCs varied by specific complication and procedure type, ranging from 0.5% for fat necrosis after mastectomy-only to 7.2% for dehiscence after mastectomy + flap. The percentage of NIWCs resulting in surgical wound care varied from 50% (210/416) for mastectomy + flap to 60% (507/843) for mastectomy + implant. Early implant removal within 60 days occurred after 6.2% of mastectomy + implant; 66% of the early implant removals were due to NIWCs and/or surgical site infection. Conclusions The rate of NIWC was approximately two-fold higher after mastectomy with IR than after mastectomy-only. NIWCs were associated with additional surgical treatment, particularly in women with implant reconstruction, and with early implant loss. PMID:27010582

  4. Bone Response to Surface-Modified Titanium Implants: Studies on the Early Tissue Response to Implants with Different Surface Characteristics

    PubMed Central

    Larsson Wexell, C.; Thomsen, P.; Aronsson, B.-O.; Tengvall, P.; Rodahl, M.; Lausmaa, J.; Kasemo, B.; Ericson, L. E.

    2013-01-01

    In a series of experimental studies, the bone formation around systematically modified titanium implants is analyzed. In the present study, three different surface modifications were prepared and evaluated. Glow-discharge cleaning and oxidizing resulted in a highly stoichiometric TiO2 surface, while a glow-discharge treatment in nitrogen gas resulted in implants with essentially a surface of titanium nitride, covered with a very thin titanium oxide. Finally, hydrogen peroxide treatment of implants resulted in an almost stoichiometric TiO2, rich in hydroxyl groups on the surface. Machined commercially pure titanium implants served as controls. Scanning Auger Electron Spectroscopy, Scanning Electron Microscopy, and Atomic Force Microscopy revealed no significant differences in oxide thickness or surface roughness parameters, but differences in the surface chemical composition and apparent topography were observed. After surface preparation, the implants were inserted in cortical bone of rabbits and evaluated after 1, 3, and 6 weeks. Light microscopic evaluation of the tissue response showed that all implants were in contact with bone and had a large proportion of newly formed bone within the threads after 6 weeks. There were no morphological differences between the four groups. Our study shows that a high degree of bone contact and bone formation can be achieved with titanium implants of different surface composition and topography. PMID:24174936

  5. Early bone growth on the surface of titanium implants in rat femur is enhanced by an amorphous diamond coating.

    PubMed

    Jaatinen, Jarkko J P; Korhonen, Rami K; Pelttari, Alpo; Helminen, Heikki J; Korhonen, Hannu; Lappalainen, Reijo; Kröger, Heikki

    2011-08-01

    Amorphous diamond (AD) is a durable and compatible biomaterial for joint prostheses. Knowledge regarding bone growth on AD-coated implants and their early-stage osseointegration is poor. We investigated bone growth on AD-coated cementless intramedullary implants implanted in rats. Titanium was chosen as a reference due to its well-known performance. We placed AD-coated and non-coated titanium implants (R(a) ≈ 0.2 μm) into the femoral bone marrow of 25 rats. The animals were divided in 2 groups according to implant coating and they were killed after 4 or 12 weeks. The osseointegration of the implants was examined from hard tissue specimens by measuring the new bone formation on their surface. 4 weeks after the operation, the thickness of new bone in the AD-coated group was greater than that in the non-coated group (15.3 (SD 7.1) μm vs. 7.6 (SD 6.0) μm). 12 weeks after the operation, the thickness of new bone was similar in the non-coated group and in the AD-coated group. We conclude that AD coating of femoral implants can enhance bone ongrowth in rats in the acute, early stage after the operation and might be an improvement over earlier coatings.

  6. Histomorphometry and bone mechanical property evolution around different implant systems at early healing stages: an experimental study in dogs.

    PubMed

    Jimbo, Ryo; Anchieta, Rodolfo; Baldassarri, Marta; Granato, Rodrigo; Marin, Charles; Teixeira, Hellen S; Tovar, Nick; Vandeweghe, Stefan; Janal, Malvin N; Coelho, Paulo G

    2013-12-01

    Commercial implants differ at macro-, micro-, and nanolevels, which makes it difficult to distinguish their effect on osseointegration. The aim of this study was to evaluate the early integration of 5 commercially available implants (Astra OsseoSpeed, Straumann SLA, Intra-Lock Blossom Ossean, Nobel Active, and OsseoFix) by histomorphometry and nanoindentation. Implants were installed in the tibiae of 18 beagle dogs. Samples were retrieved at 1, 3, and 6 weeks (n = 6 for each time point) and were histologically and nanomechanically evaluated. The results presented that both time (P < 0.01) and implant system and time interaction (P < 0.02) significantly affected the bone-to-implant contact (BIC). At 1 week, the different groups presented statistically different outcomes. No significant changes in BIC were noted thereafter. There were no significant differences in rank elastic modulus (E) or in rank hardness (H) for time (E: P > 0.80; H: P > 0.75) or implant system (E: P > 0.90; H: P > 0.85). The effect of different implant designs on osseointegration was evident especially at early stages of bone healing.

  7. Morpho-syntactic reading comprehension in children with early and late cochlear implants.

    PubMed

    López-Higes, Ramón; Gallego, Carlos; Martín-Aragoneses, María Teresa; Melle, Natalia

    2015-04-01

    This study explores morpho-syntactic reading comprehension in 19 Spanish children who received a cochlear implant (CI) before 24 months of age (early CI [e-CI]) and 19 Spanish children who received a CI after 24 months (late CI [l-CI]). They all were in primary school and were compared to a hearing control (HC) group of 19 children. Tests of perceptual reasoning, working memory, receptive vocabulary, and morpho-syntactic comprehension were used in the assessment. It was observed that while children with l-CI showed a delay, those with e-CI reached a level close to that which was obtained by their control peers in morpho-syntactic comprehension. Thus, results confirm a positive effect of early implantation on morpho-syntactic reading comprehension. Inflectional morphology and simple sentence comprehension were noted to be better in the e-CI group than in the l-CI group. The most important factor in distinguishing between the HC and l-CI groups or the e-CI and l-CI groups was verbal inflectional morphology. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Flow Test to Predict Early Hypotony and Hypertensive Phase After Ahmed Glaucoma Valve (AGV) Surgical Implantation.

    PubMed

    Cheng, Jason; Beltran-Agullo, Laura; Buys, Yvonne M; Moss, Edward B; Gonzalez, Johanna; Trope, Graham E

    2016-06-01

    To assess the validity of a preimplantation flow test to predict early hypotony [intraocular pressure (IOP)≤5 mm Hg on 2 consecutive visits and hypertensive phase (HP) (IOP>21 mm Hg) after Ahmed Glaucoma Valve (AGV) implantation. Prospective interventional study on patients receiving an AGV. A preimplantation flow test using a gravity-driven reservoir and an open manometer was performed on all AGVs. Opening pressure (OP) and closing pressure (CP) were defined as the pressure at which fluid was seen to flow or stop flowing through the AGV, respectively. OP and CP were measured twice per AGV. Patients were followed for 12 weeks. In total, 20 eyes from 19 patients were enrolled. At 12 weeks the mean IOP decreased from 29.2±9.1 to 16.8±5.2 mm Hg (P<0.01). The mean AGV OP was 17.5±5.4 mm Hg and the mean CP was 6.7±2.3 mm Hg. Early (within 2 wk postoperative) HP occurred in 37% and hypotony in 16% of cases. An 18 mm Hg cutoff for the OP gave a sensitivity of 0.71, specificity of 0.83, positive predictive value of 0.71, and negative predictive value of 0.83 for predicting an early HP. A 7 mm Hg cutoff for the CP yielded a sensitivity of 1.0, specificity of 0.38, positive predictive value of 0.23, and negative predictive value of 1.0 for predicting hypotony. Preoperative OP and CP may predict early hypotony or HP and may be used as a guide as to which AGV valves to discard before implantation surgery.

  9. Metal Ion-Loaded Nanofibre Matrices for Calcification Inhibition in Polyurethane Implants

    PubMed Central

    Singh, Charanpreet; Wang, Xungai

    2017-01-01

    Pathologic calcification leads to structural deterioration of implant materials via stiffening, stress cracking, and other structural disintegration mechanisms, and the effect can be critical for implants intended for long-term or permanent implantation. This study demonstrates the potential of using specific metal ions (MI)s for inhibiting pathological calcification in polyurethane (PU) implants. The hypothesis of using MIs as anti-calcification agents was based on the natural calcium-antagonist role of Mg2+ ions in human body, and the anti-calcification effect of Fe3+ ions in bio-prosthetic heart valves has previously been confirmed. In vitro calcification results indicated that a protective covering mesh of MI-doped PU can prevent calcification by preventing hydroxyapatite crystal growth. However, microstructure and mechanical characterisation revealed oxidative degradation effects from Fe3+ ions on the mechanical properties of the PU matrix. Therefore, from both a mechanical and anti-calcification effects point of view, Mg2+ ions are more promising candidates than Fe3+ ions. The in vitro MI release experiments demonstrated that PU microphase separation and the structural design of PU-MI matrices were important determinants of release kinetics. Increased phase separation in doped PU assisted in consistent long-term release of dissolved MIs from both hard and soft segments of the PU. The use of a composite-sandwich mesh design prevented an initial burst release which improved the late (>20 days) release rate of MIs from the matrix. PMID:28644382

  10. Enhancing of Osseointegration with Propolis-Loaded TiO2 Nanotubes in Rat Mandible for Dental Implants

    PubMed Central

    Somsanith, Nithideth; Jang, Young-Seok; Lee, Young-Hee; Yi, Ho-Keun; Kim, Kyoung-A; Bae, Tae-Sung; Lee, Min-Ho

    2018-01-01

    TiO2 nanotubes (TNT) formation is beneficial for improving bone cell–material interaction and drug delivery for Ti dental implants. Among the natural drugs to be installed in TNT, selected propolis has antibacterial and anti-inflammatory properties. It is a resinous natural product which is collected by the honeybees from the various types of plants with their salivary enzymes. This study concludes that TNT loaded with a propolis (PL-TNT-Ti) dental implant has the ability to improve osseointegration. The propolis particles were embedded within the TNT or adhered to the top. In a cytotoxicity test using osteoblast, PL-TNT-Ti group exhibited an increased cell proliferation and differentiation. A Sprague Dawley rat mandibular model was used to evaluate the osseointegration and bone bonding of TNT or PL-TNT-Ti. From the µ-CT and hematoxylin and eosin (HE) histological results after implantation at 1 and 4 weeks to rat mandibular, an increase in the extent of new bone formation and mineral density around the PL-TNT-Ti implant was confirmed. The Masson’s trichrome staining showed the expression of well-formed collagenous for bone formation on the PL-TNT-Ti. Immunohistochemistry staining indicate that bone morphogenetic proteins (BMP-2 and BMP-7) around the PL-TNT-Ti increased the expression of collagen fibers and of osteogenic differentiation whereas the expression of inflammatory cytokine such as interleukin-1 beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) is decreased. PMID:29301269

  11. Unknown loads affect force production capacity in early phases of bench press throws.

    PubMed

    Hernández Davó, J L; Sabido Solana, R; Sarabia Marínm, J M; Sánchez Martos, Á; Moya Ramón, M

    2015-10-01

    Explosive strength training aims to improve force generation in early phases of movement due to its importance in sport performance. The present study examined the influence of lack of knowledge about the load lifted in explosive parameters during bench press throws. Thirteen healthy young men (22.8±2.0 years) participated in the study. Participants performed bench press throws with three different loads (30, 50 and 70% of 1 repetition maximum) in two different conditions (known and unknown loads). In unknown condition, loads were changed within sets in each repetition and participants did not know the load, whereas in known condition the load did not change within sets and participants had knowledge about the load lifted. Results of repeated-measures ANOVA revealed that unknown conditions involves higher power in the first 30, 50, 100 and 150 ms with the three loads, higher values of ratio of force development in those first instants, and differences in time to reach maximal rate of force development with 50 and 70% of 1 repetition maximum. This study showed that unknown conditions elicit higher values of explosive parameters in early phases of bench press throws, thereby this kind of methodology could be considered in explosive strength training.

  12. Can human mesenchymal stem cells survive on a NiTi implant material subjected to cyclic loading?

    PubMed

    Habijan, T; Glogowski, T; Kühn, S; Pohl, M; Wittsiepe, J; Greulich, C; Eggeler, G; Schildhauer, T A; Köller, M

    2011-06-01

    Nickel-titanium shape memory alloys (NiTi-SMAs) exhibit mechanical and chemical properties which make them attractive candidate materials for various types of biomedical applications. However, the high nickel content of NiTi-SMAs may result in adverse tissue reactions, especially when they are considered for load-bearing implants. It is generally assumed that a protective titanium oxide layer separates the metallic alloy from its environment and that this explains the good biocompatibility of NiTi. Cyclic loading may result in failure of the protective oxide layer. The scientific objective of this work was to find out whether cyclic dynamic strain, in a range relevant for orthopedic implants, diminishes the biocompatibility of NiTi-SMAs. In order to analyze the biocompatibility of NiTi-SMA surfaces subjected to cyclic loading, NiTi-SMA tensile specimens were preloaded with mesenchymal stem cells, transferred to a sterile cell culture system and fixed to the pull rods of a tensile testing machine. Eighty-six thousand and four hundred strain cycles at 2% pseudoelastic strain were performed for a period of 24 h or 7 days. Cytokines (IL-6, IL-8 and VEGF) and nickel ion release were determined within the cell culture medium. Adherent cells on the tensile specimens were stained with calcein-AM and propidium iodide to determine cell viability. Dynamic loading of the tensile specimens did not influence the viability of adherent human mesenchymal stem cells (hMSCs) after 24 h or 7 days compared with the non-strained control. Dynamic cycles of loading and unloading did not affect nickel ion release from the tensile specimens. The release of IL-6 from hMSCs cultured under dynamic conditions was significantly higher after mechanical load (873 pg ml(-1)) compared with static conditions (323 pg ml(-1)). The present work demonstrates that a new type of mechanical in vitro cell culture experiment can provide information which previously could only be obtained in large animal

  13. A Systematic Review on Immediate Loading of Implants Used to Support Overdentures Opposed by Conventional Prostheses: Factors That Might Influence Clinical Outcomes.

    PubMed

    Zygogiannis, Kostas; Wismeijer, Daniel; Aartman, Irene Ha; Osman, Reham B

    2016-01-01

    Different treatment protocols in terms of number, diameter, and suprastructure design have been proposed for immediately loaded implants that are used to support mandibular overdentures opposed by maxillary conventional dentures. The aim of this study was to investigate the influence of these protocols on survival rates as well as clinical and prosthodontic outcomes. Several electronic databases were searched for all relevant articles published from 1966 to June 2014. Only randomized controlled trials and prospective studies with a minimum follow-up of 12 months were selected. The primary outcomes of interest were the success and survival rates of the implants. Prosthodontic complications were also evaluated. Fourteen studies fulfilled the inclusion criteria. Of the studies identified, nine were randomized controlled trials and five were prospective studies. The mean follow-up period was 3 years or less for the vast majority of the studies. The reported survival and success rates were comparable to that of conventional loading for most of the included studies. No specific immediate loading protocol seemed to perform better in terms of clinical and prosthodontic outcomes. Immediate loading protocols of mandibular overdentures seem to be a viable alternative to conventional loading. It was not possible to recommend a specific treatment protocol related to the number, diameter of the implants, and attachment system used. Long-term, well-designed studies comparing different immediate loading modalities could help to establish a protocol that delivers the most clinically predictable, efficient, and cost-effective outcome for edentulous patients in need of implant overdentures.

  14. A prospective randomized study on the immediate loading of mandibular overdentures supported by one or two implants; a 3 year follow-up report.

    PubMed

    Kronstrom, Mats; Davis, Ben; Loney, Robert; Gerrow, Jack; Hollender, Lars

    2014-06-01

    The objective of the study was to evaluate and compare treatments with mandibular overdentures supported by one or two immediately placed implants 3 years after loading. Thirty-six edentulous subjects were eligible for inclusion. Using a random sampling system, one or two implants were placed in the mandible. Separate ball attachments were connected to the implants, and the denture was relined and delivered the day of surgery with the retentive components incorporated in the denture base. At the follow-up examinations peri-implant bone levels, implant and denture stability/retention, and need for maintenance and adjustments were evaluated. Moreover, the OHIP-EDENT questionnaire was used to measure patient satisfaction. Nineteen subjects (10 men and 9 women) with a mean age of 56 years were available for the 3-year follow-up examination. The group with 1 implant (Group 1) consisted of 11 subjects (5 women and 6 men) while the remaining 8 (5 women and 3 men) belonged to Group2. Nine subjects had been excluded during the first year due to failing implants, 6 had moved, 1 had died, and 1 reported severe illness. No implant failures between the 12-and 36 month follow-up were observed. The mean peri-implant bone change was.86 mm and the Implant Stability Quotient showed only minor changes with no significant difference between the groups when compared with the 12-month follow-up. Patient satisfaction scores increased significantly when compared with the baseline values and continued to be high for both groups and need for denture maintenance was low. No significant differences were found between subjects in the two groups with respect to implant survival and peri implant bone loss, and patient satisfaction scores continued to be high for both groups. Need for denture maintenance was low in both groups. © 2012 Wiley Periodicals, Inc.

  15. Early Listening and Speaking Skills Predict Later Reading Proficiency in Pediatric Cochlear Implant Users

    PubMed Central

    Spencer, Linda J.; Oleson, Jacob J.

    2011-01-01

    Objectives Previous studies have reported that children who use cochlear implants (CIs) tend to achieve higher reading levels than their peers with profound hearing loss who use hearing aids. The purpose of this study was to investigate the influences of auditory information provided by the CI on the later reading skills of children born with profound deafness. The hypothesis was that there would be a positive and predictive relationship between earlier speech perception, production, and subsequent reading comprehension. Design The speech perception and production skills at the vowel, consonant, phoneme, and word level of 72 children with prelingual, profound hearing loss were assessed after 48 mos of CI use. The children's reading skills were subsequently assessed using word and passage comprehension measures after an average of 89.5 mos of CI use. A regression analysis determined the amount of variance in reading that could be explained by the variables of perception, production, and socioeconomic status. Results Regression analysis revealed that it was possible to explain 59% of the variance of later reading skills by assessing the early speech perception and production performance. The results indicated that early speech perception and production skills of children with profound hearing loss who receive CIs predict future reading achievement skills. Furthermore, the study implies that better early speech perception and production skills result in higher reading achievement. It is speculated that the early access to sound helps to build better phonological processing skills, which is one of the likely contributors to eventual reading success. PMID:18595191

  16. Infants Understand Deceptive Intentions to Implant False Beliefs about Identity: New Evidence for Early Mentalistic Reasoning

    PubMed Central

    Scott, Rose M.; Richman, Josh C.; Baillargeon, Renée

    2015-01-01

    Are infants capable of representing false beliefs, as the mentalistic account of early psychological reasoning suggests, or are they incapable of doing so, as the minimalist account suggests? The present research sought to shed light on this debate by testing the minimalist claim that a signature limit of early psychological reasoning is a specific inability to understand false beliefs about identity: because of their limited representational capabilities, infants should be unable to make sense of situations where an agent mistakes one object for another, visually identical object. To evaluate this claim, three experiments examined whether 17-month-olds could reason about the actions of a deceptive agent who sought to implant in another agent a false belief about the identity of an object. In each experiment, a thief attempted to secretly steal a desirable rattling toy during its owner’s absence by substituting a less desirable silent toy. Infants realized that this substitution could be effective only if the silent toy was visually identical to the rattling toy (Experiment 1) and the owner did not routinely shake her toy when she returned (Experiment 2). When these conditions were met, infants expected the owner to be deceived and to mistake the silent toy for the rattling toy she had left behind (Experiment 3). Together, these results cast doubt on the minimalist claim that infants cannot represent false beliefs about identity. More generally, these results indicate that infants in the 2nd year of life can reason not only about the actions of agents who hold false beliefs, but also about the actions of agents who seek to implant false beliefs, thus providing new support for the mentalistic claim that an abstract capacity to reason about false beliefs emerges early in human development. PMID:26374383

  17. Right ventricular response to pulsatile load is associated with early right heart failure and mortality after left ventricular assist device.

    PubMed

    Grandin, E Wilson; Zamani, Payman; Mazurek, Jeremy A; Troutman, Gregory S; Birati, Edo Y; Vorovich, Esther; Chirinos, Julio A; Tedford, Ryan J; Margulies, Kenneth B; Atluri, Pavan; Rame, J Eduardo

    2017-01-01

    Right ventricular (RV) adaptation to afterload is crucial for patients undergoing continuous-flow left ventricular assist device (cf-LVAD) implantation. We hypothesized that stratifying patients by RV pulsatile load, using pulmonary arterial compliance (PAC), and RV response to load, using the ratio of central venous to pulmonary capillary wedge pressure (CVP:PCWP), would identify patients at high risk for early right heart failure (RHF) and 6-month mortality after cf-LVAD. During the period from January 2008 to June 2014, we identified 151 patients at our center with complete hemodynamics prior to cf-LVAD. Pulsatile load was estimated using PAC indexed to body surface area (BSA), according to the formula: indexed PAC (PACi) = [SV / (PA systolic - PA diastolic )] / BSA, where SV is stroke volume and PA is pulmonary artery. Patients were divided into 4 hemodynamic groups by PACi and CVP:PCWP. RHF was defined as the need for unplanned RVAD, inotropic support ≥14 days or death due to RHF within 14 days. Risk factors for RHF and 6-month mortality were examined using logistic regression and Cox proportional hazards modeling. Sixty-one patients (40.4%) developed RHF and 34 patients (22.5%) died within 6 months. Patients with RHF had lower PACi (0.92 vs 1.17 ml/mm Hg/m 2 , p = 0.008) and higher CVP:PCWP (0.48 vs 0.37, p = 0.001). Higher PACi was associated with reduced risk of RHF (adjusted odds ratio [adj-OR] 0.61, 95% confidence interval [CI] 0.39 to 0.94, p = 0.025) and low PACi with increased risk of 6-month mortality (adjusted hazard ratio [adj-HR] 3.18, 95% CI 1.40 to 7.25, p = 0.006). Compared to patients with low load (high PACi) and adequate right heart response to load (low CVP:PCWP), patients with low PACi and high CVP:PCWP had an increased risk of RHF (OR 4.74, 95% CI 1.23 to 18.24, p = 0.02) and 6-month mortality (HR 8.68, 95% CI 2.79 to 26.99, p < 0.001). A hemodynamic profile combining RV pulsatile load and response to load identifies patients at high

  18. Timed artificial insemination should be performed early when used norgestomet ear implants are applied for synchronizing ovulation in beef heifers.

    PubMed

    Sá Filho, M F; Penteado, L; Siqueira, G R; Soares, J G; Mendanha, M F; Macedo, G G; Baruselli, P S

    2013-10-01

    The present study evaluated the effect of the type of norgestomet ear implant (new vs. used) on the ovarian follicular response (experiment 1) and pregnancy per artificial insemination (AI) (P/AI; experiment 2) of beef heifers subjected to an estradiol plus progestin timed artificial insemination (TAI) program. In experiment 1, 57 cyclic beef heifers were randomly assigned to one of two groups according to the type (new or previously used for 9 days) of norgestomet ear (NORG) implant. At the time of NORG implant insertion, the heifers were treated with 2 mg of intramuscular estradiol benzoate. Eight days later, the NORG implants were removed, and the heifers received an intramuscular administration of 150 μg of d-cloprostenol, 300 IU of equine chorionic gonadotropin, and 0.5 mg of estradiol cypionate. The heifers had their ovaries scanned every 12 hours from the time of NORG implant removal to 96 hours after verifying the occurrence and timing of ovulation. No difference (P = 0.89) was observed in the ovulation rates between the two treatments (new = 80.0%; 24/30 vs. used = 81.5%; 22/27). However, the heifers treated with a used NORG implant had (P = 0.04) higher proportion (36.4%; 8/22) of early ovulation (between 36 and 48 hours after NORG implant removal) compared with the heifers treated with a new NORG implant (8.3%; 2/24). In experiment 2, at the beginning of the synchronization protocol, 416 beef heifers were randomly assigned into two groups, as described in the experiment 1. Two days after the NORG implant removal, the heifers were reassigned to be inseminated at 48 or 54 hours after NORG implant removal. There was an interaction (P = 0.03) between the type of NORG implant and the timing of TAI on P/AI. The timing of insemination only had an effect (P = 0.02) on the P/AI when the heifers were treated with a used NORG implant [(TAI 54 hours = 41.9% (44/105) vs. TAI 48 hours = 58.6% (58/99)]. In conclusion, beef heifers synchronized with a used NORG implant

  19. Randomized controlled multicenter study comparing short dental implants (6 mm) versus longer dental implants (11-15 mm) in combination with sinus floor elevation procedures. Part 2: clinical and radiographic outcomes at 1 year of loading.

    PubMed

    Schincaglia, Gian Pietro; Thoma, Daniel S; Haas, Robert; Tutak, Marcin; Garcia, Abel; Taylor, Thomas D; Hämmerle, Christoph H F

    2015-11-01

    To compare, clinically and radiographically, short dental implants (6 mm) to long implants (11-15 mm) placed with sinus grafting. Participants with 5-7 mm of bone height in the posterior maxilla were randomly allocated to receive short implants (GS) or long implants with sinus grafting (GG). Implants were loaded with single crowns 6 months after placement (PR). Patients were re-evaluated 12 months after loading (FU-1). Outcome variables included: Implant survival rate (CSR), marginal bone level alteration (MBL), periodontal probing depth (PPD), bleeding on probing (BoP), plaque control record (PCR) and crown-to-implant ratios (C/I). Statistical analysis was performed using parametric tests. In 97 subjects, 132 implants were re-evaluated at FU-1. The CSR was 100%. The MBL from implant placement (IP) to (PR) was -0.22 ± 0.4 mm for GG and -0.3 ± 0.45 mm for GS (p < 0.001). MBL from IP to FU-1 was -0.37 ± 0.59 mm for GG and -0.22 ± 0.3 mm for GS (p < 0.001). Intergroup comparisons showed non-significant differences for MBL (p > 0.05), PPD (p = 1) and PCR (p = 0.09). BoP was higher in the GS (p = 0.04). The C/I was 0.99 ± 0.17 for GG and 1.86 ± 0.23 for GS (p < 0.001). No correlation was observed between C/I and MBL, (GG: p = 0.13; GS: p = 0.38). Both treatment modalities provided similar outcomes. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Effect of abutment height on interproximal implant bone level in the early healing: A randomized clinical trial.

    PubMed

    Blanco, Juan; Pico, Alexandre; Caneiro, Leticia; Nóvoa, Lourdes; Batalla, Pilar; Martín-Lancharro, Pablo

    2018-01-01

    The aim of this randomized clinical trial was to compare the effect on the interproximal implant bone loss (IBL) of two different heights (1 and 3 mm) of definitive abutments placed at bone level implants with a platform switched design. Twenty-two patients received forty-four implants (6.5-10 mm length and 3.5-4 mm diameter) to replace at least two adjacent missing teeth, one bridge set to each patient-two implants per bridge. Patients were randomly allocated, and two different abutment heights, 1 and 3 mm using only one abutment height per bridge, were used. Clinical and radiological measurements were performed at 3 and 6 months after surgery. Interproximal bone level changes were compared between treatment groups. The association between IBL and categorical variables (history of periodontitis, smoking, implant location, implant diameter, implant length, insertion torque, width of keratinized mucosa, bone density, gingival biotype and antagonist) was also performed. At 3 months, implants with a 1-mm abutment had significantly greater IBL (0.83 ± 0.19 mm) compared to implants with a 3-mm abutment (0.14 ± 0.08 mm). At 6 months, a greater IBL was observed at implants with 1-mm abutments compared to implants with 3-mm abutments (0.91 ± 0.19 vs. 0.11 ± 0.09 mm). The analysis of the relation between patient characteristics and clinical variables with IBL revealed no significant differences at any moment except for smoking. Abutment height is an important factor to maintain interproximal implant bone level in early healing. Short abutments led to a greater interproximal bone loss in comparison with long abutments after 6 months. Other variables except smoking showed no relation with interproximal bone loss in early healing. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Misfit and fracture load of implant-supported monolithic crowns in zirconia-reinforced lithium silicate.

    PubMed

    Gomes, Rafael Soares; Souza, Caroline Mathias Carvalho de; Bergamo, Edmara Tatiely Pedroso; Bordin, Dimorvan; Del Bel Cury, Altair Antoninha

    2017-01-01

    In this study, marginal and internal misfit and fracture load with and without thermal-mechanical aging (TMA) of monolithic ZLS and lithium disilicate (LDS) crowns were evaluated. Crowns were milled using a computer-aided design/computer-aided manufacturing system. Marginal gaps (MGs), absolute marginal discrepancy (AMD), axial gaps, and occlusal gaps were measured by X-ray microtomography (n=8). For fracture load testing, crowns were cemented in a universal abutment, and divided into four groups: ZLS without TMA, ZLS with TMA, LDS without TMA, and LDS with TMA (n=10). TMA groups were subjected to 10,000 thermal cycles (5-55°C) and 1,000,000 mechanical cycles (200 N, 3.8 Hz). All groups were subjected to compressive strength testing in a universal testing machine at a crosshead speed of 1 mm/min until failure. Student's t-test was used to examine misfit, two-way analysis of variance was used to analyze fracture load, and Pearson's correlation coefficients for misfit and fracture load were calculated (α=0.05). The materials were analyzed according to Weibull distribution, with 95% confidence intervals. Average MG (p<0.001) and AMD (p=0.003) values were greater in ZLS than in LDS crowns. TMA did not affect the fracture load of either material. However, fracture loads of ZLS crowns were lower than those of LDS crowns (p<0.001). Fracture load was moderately correlated with MG (r=-0.553) and AMD (r=-0.497). ZLS with TMA was least reliable, according to Weibull probability. Within the limitations of this study, ZLS crowns had lower fracture load values and greater marginal misfit than did LDS crowns, although these values were within acceptable limits.

  2. [Early efficacy of dexamethasone implant (OZURDEX®) in diabetic macular edema: Real life study].

    PubMed

    Sarda, V; Fajnkuchen, F; Nghiem-Buffet, S; Grenet, T; Chaine, G; Giocanti-Auregan, A

    2017-05-01

    To assess early efficacy of dexamethasone intravitreal implant 0.7mg (OZURDEX ® ) at the time of peak efficacy (2 months after injection) in patients with decreased visual acuity secondary to diabetic macular edema (DME). Retrospective monocentric study. Inclusion criteria were best-corrected visual acuity (BCVA)≤70 letters (20/40) due to DME and central retinal thickness (CRT)≥300 microns (Cirrus 2, Carl Zeiss Meditec, Inc, Dublin). Enrolled patients could be treatment naive or not (after failure of laser photocoagulation and/or anti-VEGF therapy). Follow-up was at least 6 months. Our primary endpoint was BCVA gain at M2 after injection. Secondary endpoints were best-corrected visual acuity at 2 and 4 months, central retinal thickness at 2 and 4 months, mean interval between 2 injections, and adverse events. Nineteen eyes of 19 patients were included in this study. The mean age was 67.45 years, sex ratio was 2.17 men/women, and the patients were all type 2 diabetics. Three of 19 patients were treatment naive for anti-VEGF intravitreal injection, and 52.3% were pseudophakic (10/19 patients). The mean gain of BCVA at M2 was +7.7 letters. The mean BCVA was 51.1 ETDRS letters at baseline and 58.8 at M2. Mean CRT was 568.9μm at baseline and 291.2μm at M2. Treatment with dexamethasone implant was mainly a second-line treatment after failure of other treatments (macular laser photocoagulation and/or intravitreal injection of anti-VEGF). Three patients were naive of anti-VEGF treatment. Intraocular pressure≥25mmHg was found in 2 patients, and controlled medically. No glaucoma surgery was performed. The dexamethasone implant (OZURDEX ® ) allows an anatomical and functional improvement in patients suffering from vision loss due to DME. In this series, the implant was well tolerated. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  3. Hypertensive phase and early complications after Ahmed glaucoma valve implantation with intraoperative subtenon triamcinolone acetonide

    PubMed Central

    Turalba, Angela V; Pasquale, Louis R

    2014-01-01

    Objective To evaluate intraoperative subtenon triamcinolone acetonide (TA) as an adjunct to Ahmed glaucoma valve (AGV) implantation. Design Retrospective comparative case series. Participants Forty-two consecutive cases of uncontrolled glaucoma undergoing AGV implantation: 19 eyes receiving intraoperative subtenon TA and 23 eyes that did not receive TA. Methods A retrospective chart review was performed on consecutive pseudophakic adult patients with uncontrolled glaucoma undergoing AGV with and without intraoperative subtenon TA injection by a single surgeon. Clinical data were collected from 42 eyes and analyzed for the first 6 months after surgery. Main outcome measures Primary outcomes included intraocular pressure (IOP) and number of glaucoma medications prior to and after AGV implantation. The hypertensive phase (HP) was defined as an IOP measurement of greater than 21 mmHg (with or without medications) during the 6-month postoperative period that was not a result of tube obstruction, retraction, or malfunction. Postoperative complications and visual acuity were analyzed as secondary outcome measures. Results Five out of 19 (26%) TA cases and 12 out of 23 (52%) non-TA cases developed the HP (P=0.027). Mean IOP (14.2±4.6 in TA cases versus [vs] 14.7±5.0 mmHg in non-TA cases; P=0.78), and number of glaucoma medications needed (1.8±1.3 in TA cases vs 1.6±1.1 in the comparison group; P=0.65) were similar between both groups at 6 months. Although rates of serious complications did not differ between the groups (13% in the TA group vs 16% in the non-TA group), early tube erosion (n=1) and bacterial endophthalmitis (n=1) were noted with TA but not in the non-TA group. Conclusions Subtenon TA injection during AGV implantation may decrease the occurrence of the HP but does not alter the ultimate IOP outcome and may pose increased risk of serious complications within the first 6 months of surgery. PMID:25050061

  4. A novel aragonite-based scaffold for osteochondral regeneration: early experience on human implants and technical developments.

    PubMed

    Kon, Elizaveta; Robinson, Dror; Verdonk, Peter; Drobnic, Matej; Patrascu, Jenel Mariano; Dulic, Oliver; Gavrilovic, Gordon; Filardo, Giuseppe

    2016-12-01

    Chondral and osteochondral lesions represent a debilitating disease. Untreated lesions remain a risk factor for more extensive joint damage. The objective of this clinical study is to evaluate safety and early results of an aragonite-based scaffold used for osteochondral unit repair, by analysing both clinical outcome and MRI results, as well as the benefits of the procedure optimization through novel tapered shaped implants. A crystalline aragonite bi-phasic scaffold was implanted in patients affected by focal chondral-osteochondral knee lesions of the condyle and trochlea. Twenty-one patients (17 men, 4 women with a mean age of 31.0 ± 8.6 years) without severe OA received tapered shaped implants for the treatment of 2.5 ±1.7 cm 2 sized defects. The control group consisted of 76 patients selected according to the same criteria from a database of patients who previously underwent implantation of cylindrical-shaped implants. The clinical outcome of all patients was evaluated with the IKDC subjective score, the Lysholm score, and all 5 KOOS subscales administered preoperatively and at 6 and 12 months after surgery, while MRI evaluation was performed at the 12 month follow-up. A statistically significant improvement in all clinical scores was documented both in the tapered implants and the cylindrical group. No difference could be detected in the comparison between the improvement obtained with the two implant types, neither in the clinical nor in imaging evaluations. A difference could be detected instead in terms of revision rate, which was lower in the tapered implant group with no implant removal - 0% vs 8/76-10.5% failures in the cylindrical implants. This study highlighted both safety and potential of a novel aragonite-based scaffold for the treatment of chondral and osteochondral lesions in humans. A tapered shape relative to the cylindrical shaped implant design, improved the scaffold's safety profile. Tapered scaffolds maintain the clinical improvement

  5. The influence of repeated abutment changes on peri-implant tissue stability: 3-year post-loading results from a multicentre randomised controlled trial.

    PubMed

    Bressan, Eriberto; Grusovin, Maria Gabriella; D'Avenia, Ferdinando; Neumann, Konrad; Sbricoli, Luca; Luongo, Giuseppe; Esposito, Marco

    To evaluate the influence of at least three abutment disconnections in conventional loaded implants against placement of a definitive abutment in immediately non-occlusal loaded implants on hard and soft tissue changes. A secondary aim was to evaluate whether the presence of less than 2 mm of keratinised mucosa is associated with increased peri-implant marginal bone loss and soft tissue recessions. Eighty patients requiring one single crown or one fixed partial prosthesis supported by a maximum of three implants were randomised, after implants were placed with more than 35 Ncm, according to a parallel group design to receive definitive abutments that were loaded immediately (definitive abutment or immediate loading group) or transmucosal abutments, which were delayed loaded after 3 months and removed at least three times: 1. At impression taking (3 months after implant placement); 2. When checking the zirconium core on titanium abutments at single crowns or the fitting the metal structure at prostheses supported by multiple implants; 3. At delivery of the definitive prostheses (repeated disconnection or conventional loading group). Patients were treated at four centres and each patient contributed to the study, with only one prosthesis followed for 3 years after initial loading. Outcome measures were: prosthesis failures, implant failures, complications, pink aesthetic score (PES), buccal recessions, patient satisfaction, peri-implant marginal bone level changes and height of the keratinised mucosa. Forty patients were randomly allocated to each group according to a parallel group design. Six patients from the definitive abutment group dropped out or died, and one left from the repeated disconnection group. One implant, from the repeated disconnection group, fractured (difference = 3%; CI 95%: -2%, 8%; P = 1). Four provisional crowns and one definitive single crown had to be remade because of poor fitting, and one definitive crown and one definitive prosthesis

  6. A novel ropivacaine-loaded in situ forming implant prolongs the effect of local analgesia in rats

    PubMed Central

    Lu, Lei; Zhang, Wei; Wu, Xin; Wang, Xiaoyu; Zhang, Min; Zhu, Quangang; Ding, Xueying; Xu, Zhiyun

    2012-01-01

    Introduction Prolonged postoperative analgesia cannot be achieved by a single injection of local anesthetic solution. The objective of this study was to optimize the formulation of a ropivacaine hydrochloride (Ropi-HCl) loaded in situ forming implant (ISI) by addition of different co-solvents, and evaluate the in vitro release of Ropi-HCl, and the analgesic effect and toxicity of the optimized formulation in rats. Material and methods Triacetin (TA), benzyl benzoate (BB) and polyethylene glycol 400 (PEG 400) were used as additives and added to the solvent of N-methyl-2-pyrrolidone (NMP). Drug release to the surface and inner structural properties of the formed implant were evaluated by scanning electron microscopy (SEM). The analgesic effect was determined by injection near the rat sciatic nerve. Results The solvent system added with TA or BB significantly decreased the burst release, whereas PEG 400 increased the Ropi-HCl burst release from the formulation. Over 70% of the incorporated Ropi-HCl was released from all formulations in 14 days in the in vitro assay. The SEM showed that the surface of NMP-BB formulation was less porous and more homogeneous, compared with the other formulations. Compared with Ropi-HCl injection, the optimized formulation (NMP-BB) significantly prolonged the analgesic effect in 48 h (p < 0.05), with a mild degree of motor block from 3 h to 12 h. Histological evaluation of the injection site revealed only mild inflammatory infiltration without obvious pathological nerve alterations. Conclusions The biodegradable Ropi-HCl-loaded ISI system with NMP-BB may prove to be an attractive and safe alternative for the delivery of parenteral local anesthetics to prolong pain relief. PMID:24049519

  7. Anti-angiogenic drug loaded liposomes: Nanotherapy for early atherosclerotic lesions in mice

    PubMed Central

    Pont, Isabel; Calatayud-Pascual, Aracely; López-Castellano, Alicia; Albelda, Elena P.; García-España, Enrique; Martí-Bonmatí, Luis; Frias, Juan C.

    2018-01-01

    Fumagillin-loaded liposomes were injected into ApoE-KO mice. The animals were divided into several groups to test the efficacy of this anti-angiogenic drug for early treatment of atherosclerotic lesions. Statistical analysis of the lesions revealed a decrease in the lesion size after 5 weeks of treatment. PMID:29338009

  8. Misfit and fracture load of implant-supported monolithic crowns in zirconia-reinforced lithium silicate

    PubMed Central

    GOMES, Rafael Soares; de SOUZA, Caroline Mathias Carvalho; BERGAMO, Edmara Tatiely Pedroso; BORDIN, Dimorvan; DEL BEL CURY, Altair Antoninha

    2017-01-01

    Abstract Zirconia-reinforced lithium silicate (ZLS) is a ceramic that promises to have better mechanical properties than other materials with the same indications as well as improved adaptation and fracture strength. Objective In this study, marginal and internal misfit and fracture load with and without thermal-mechanical aging (TMA) of monolithic ZLS and lithium disilicate (LDS) crowns were evaluated. Material and methods Crowns were milled using a computer-aided design/computer-aided manufacturing system. Marginal gaps (MGs), absolute marginal discrepancy (AMD), axial gaps, and occlusal gaps were measured by X-ray microtomography (n=8). For fracture load testing, crowns were cemented in a universal abutment, and divided into four groups: ZLS without TMA, ZLS with TMA, LDS without TMA, and LDS with TMA (n=10). TMA groups were subjected to 10,000 thermal cycles (5-55°C) and 1,000,000 mechanical cycles (200 N, 3.8 Hz). All groups were subjected to compressive strength testing in a universal testing machine at a crosshead speed of 1 mm/min until failure. Student’s t-test was used to examine misfit, two-way analysis of variance was used to analyze fracture load, and Pearson’s correlation coefficients for misfit and fracture load were calculated (α=0.05). The materials were analyzed according to Weibull distribution, with 95% confidence intervals. Results Average MG (p<0.001) and AMD (p=0.003) values were greater in ZLS than in LDS crowns. TMA did not affect the fracture load of either material. However, fracture loads of ZLS crowns were lower than those of LDS crowns (p<0.001). Fracture load was moderately correlated with MG (r=-0.553) and AMD (r=-0.497). ZLS with TMA was least reliable, according to Weibull probability. Conclusion Within the limitations of this study, ZLS crowns had lower fracture load values and greater marginal misfit than did LDS crowns, although these values were within acceptable limits. PMID:28678947

  9. Early Complications of Immediate Loading in Edentulous Full-Arch Restorations: A Retrospective Analysis of 88 Cases.

    PubMed

    Cercadillo-Ibarguren, Iñaki; Sánchez-Torres, Alba; Figueiredo, Rui; Valmaseda-Castellón, Eduard

    To describe the clinical outcomes and complications related to provisional prostheses after full-arch implant-supported rehabilitation by means of an immediate loading protocol. This retrospective cohort study included patients who were consecutively treated with full-arch implant-supported restorations with a minimum of four implants (Replace Select Tapered TiUnite, Nobel Biocare AB) per arch and conical abutments (multi-unit, Nobel Biocare AB) by means of an immediate loading protocol. The surgical procedures were performed between May 2006 and June 2014 by a single oral surgeon. Demographic, surgical, and prosthetic variables were collected, and biologic and mechanical complications were registered. A total of 61 maxillae (57%) and 46 mandibles (43%) were treated in 88 patients (40 men and 48 women) with a mean age of 62.4 years. A total of 558 implants were placed, 295 in postextraction sockets. A total of 331 implants (59.3%) were placed in the maxilla and 227 (40.7%) in the mandible. Within a 9-month period, 18 prostheses (16.8%) fractured (15 maxillary and 3 mandibular); in nine of these patients the opposing dentition was a full-arch, implant-supported restoration, and in the remaining nine patients, it was natural dentition. Six (1.1%) maxillary and three (0.5%) mandibular implants failed. A high implant survival rate is expected in the short term following this immediate loading protocol. Fracture of the provisional prosthesis is a common finding, affecting 17% of patients, and is significantly more prevalent in patients with bruxism and in maxillary prostheses.

  10. Academic Outcomes for School-Aged Children with Severe-Profound Hearing Loss and Early Unilateral and Bilateral Cochlear Implants

    ERIC Educational Resources Information Center

    Sarant, Julia Z.; Harris, David C.; Bennet, Lisa A.

    2015-01-01

    Purpose: This study sought to (a) determine whether academic outcomes for children who received early cochlear implants (CIs) are age appropriate, (b) determine whether bilateral CI use significantly improves academic outcomes, and (c) identify other factors that are predictive of these outcomes. Method: Forty-four 8-year-old children with…

  11. Soft tissue around three different implant types after 1.5 years of functional loading without oral hygiene: a preliminary study in baboons.

    PubMed

    Watzak, Georg; Zechner, Werner; Tangl, Stefan; Vasak, Christoph; Donath, Karl; Watzek, Georg

    2006-04-01

    The purpose of this study was to determine the peri-implant soft tissue dimension (PSD) and peri-implant bone level (BL) of dental implants with different designs and surface modifications after functional loading without oral hygiene. Three types of dental implants were placed in the posterior jaws of adult baboons, three of the same design per quadrant, and fitted with fixed partial dentures. After 1.5 years of functional loading and plaque accumulation, all implants showed severe peri-implant mucositis and comparatively high BL. A histomorphometric evaluation of the sulcus depth (SD), the dimension of the junctional epithelium (JE) and the connective tissue contact (CTC) resulted in no significant differences between the three implant designs, neither in the maxilla nor in the mandible (P>0.05). The sum of SD, JE and CTC forming the PSD was nearly the same in the maxilla (commercially pure titanium, CpTi: 3.5 mm 2.9/4.1 confidence interval (CI); titanium plasma sprayed (TPS): 3.5 mm 2.9/4.2 CI; sand blasted acid-etched (GBAE): 3.2 mm 2.7/3.9 CI) and in the mandible (CpTi: 3.2 mm 2.6/3.8 CI; TPS: 3.2 mm 2.6/3.8 CI; GBAE: 3.2 mm 2.7/3.9 CI; P>0.05). There was no difference in BL around the three implant designs (maxilla: CpTi: 0.9 mm 0.5/1.6 CI; TPS: 0.9 mm 0.5/1.5CI; GBAE: 0.9 mm 0.5/1.6 CI; mandible: CpTi: 0.8 mm 0.5/1.2 CI; TPS: 0.6 mm 0.4/0.9 CI; GBAE: 0.7 mm 0.5/1.1 CI; P>0.05). Overall, the data presented did not show any significant differences in peri-implant soft tissue conditions in baboons. Moreover, plaque accumulation and propagation of peri-implant mucositis after 1.5 years of functional loading was not influenced by implant design and surface modifications in baboons.

  12. Understanding minds: early cochlear implantation and the development of theory of mind in children with profound hearing impairment.

    PubMed

    Sundqvist, Annette; Lyxell, Björn; Jönsson, Radoslava; Heimann, Mikael

    2014-03-01

    The present study investigates how auditory stimulation from cochlear implants (CI) is associated with the development of Theory of Mind (ToM) in severely and profoundly hearing impaired children with hearing parents. Previous research has shown that deaf children of hearing parents have a delayed ToM development. This is, however, not always the case with deaf children of deaf parents, who presumably are immersed in a more vivid signing environment. Sixteen children with CI (4.25 to 9.5 years of age) were tested on measures of cognitive and emotional ToM, language and cognition. Eight of the children received their first implant relatively early (before 27 months) and half of them late (after 27 months). The two groups did not differ in age, gender, language or cognition at entry of the study. ToM tests included the unexpected location task and a newly developed Swedish social-emotional ToM test. The tests aimed to test both cognitive and emotional ToM. A comparison group of typically developing hearing age matched children was also added (n=18). Compared to the comparison group, the early CI-group did not differ in emotional ToM. The late CI-group differed significantly from the comparison group on both the cognitive and emotional ToM tests. The results revealed that children with early cochlear implants solved ToM problems to a significantly higher degree than children with late implants, although the groups did not differ on language or cognitive measures at baseline. The outcome suggests that early cochlear implantation for deaf children in hearing families, in conjunction with early social and communicative stimulation in a language that is native to the parents, can provide a foundation for a more normalized ToM development. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  13. Finite element analysis of dental implant loading on atrophic and non-atrophic cancellous and cortical mandibular bone - a feasibility study.

    PubMed

    Marcián, Petr; Borák, Libor; Valášek, Jiří; Kaiser, Jozef; Florian, Zdeněk; Wolff, Jan

    2014-12-18

    The first aim of this study was to assess displacements and micro-strain induced on different grades of atrophic cortical and trabecular mandibular bone by axially loaded dental implants using finite element analysis (FEA). The second aim was to assess the micro-strain induced by different implant geometries and the levels of bone-to-implant contact (BIC) on the surrounding bone. Six mandibular bone segments demonstrating different grades of mandibular bone atrophy and various bone volume fractions (from 0.149 to 0.471) were imaged using a micro-CT device. The acquired bone STL models and implant (Brånemark, Straumann, Ankylos) were merged into a three-dimensional finite elements structure. The mean displacement value for all implants was 3.1 ±1.2 µm. Displacements were lower in the group with a strong BIC. The results indicated that the maximum strain values of cortical and cancellous bone increased with lower bone density. Strain distribution is the first and foremost dependent on the shape of bone and architecture of cancellous bone. The geometry of the implant, thread patterns, grade of bone atrophy and BIC all affect the displacement and micro-strain on the mandible bone. Preoperative finite element analysis could offer improved predictability in the long-term outlook of dental implant restorations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Early osteoblast responses to orthopedic implants: Synergy of surface roughness and chemistry of bioactive ceramic coating.

    PubMed

    Aniket; Reid, Robert; Hall, Benika; Marriott, Ian; El-Ghannam, Ahmed

    2015-06-01

    Pro-osteogenic stimulation of bone cells by bioactive ceramic-coated orthopedic implants is influenced by both surface roughness and material chemistry; however, their concomitant impact on osteoblast behavior is not well understood. The aim of this study is to investigate the effects of nano-scale roughness and chemistry of bioactive silica-calcium phosphate nanocomposite (SCPC50) coated Ti-6Al-4V on modulating early bone cell responses. Cell attachment was higher on SCPC50-coated substrates compared to the uncoated controls; however, cells on the uncoated substrate exhibited greater spreading and superior quality of F-actin filaments than cells on the SCPC50-coated substrates. The poor F-actin filament organization on SCPC50-coated substrates is thought to be due to the enhanced calcium uptake by the ceramic surface. Dissolution analyses showed that an increase in surface roughness was accompanied by increased calcium uptake, and increased phosphorous and silicon release, all of which appear to interfere with F-actin assembly and osteoblast morphology. Moreover, cell attachment onto the SCPC50-coated substrates correlated with the known adsorption of fibronectin, and was independent of surface roughness. High-throughput genome sequencing showed enhanced expression of extracellular matrix and cell differentiation related genes. These results demonstrate a synergistic relationship between bioactive ceramic coating roughness and material chemistry resulting in a phenotype that leads to early osteoblast differentiation. © 2014 Wiley Periodicals, Inc.

  15. Interferon-τ increases BoLA-I for implantation during early pregnancy in dairy cows.

    PubMed

    Zhu, Zhe; Li, Binbin; Wu, Yue; Wang, Xiao; Deng, GanZhen

    2017-11-10

    Interferon-τ (IFN-τ) signals pregnancy recognition in ruminants. We investigated the effects of IFN-τ produced by embryo trophoblastic cells (ETCs) on expression of bovine leukocyte antigen-I (BoLA-I), a bovine analogue of human MHC-I, in endometrial luminal epithelial cells (EECs) during early pregnancy in dairy cows. Expression of IFN-τ and BoLA-I was increased in endometrial tissues during early pregnancy. Expression of the anti-inflammatory cytokine IL-10 was increased in endometrial tissues, while expression of the pro-inflammatory cytokine IL-6 was decreased, indicating immunosuppression. Progesterone increased IFN-τ expression in EECs. IFN-τ increased p-STAT1 and p-STAT3 levels in EECs, but reduced TRAF3 levels. In addition, IFN-τ increased expression of BoLA-I and IL-10, but decreased expression of IL-6 in EECs. These results indicate that IFN-τ enables stable implantation in dairy cows by increasing expression of BoLA-I, and by immunosuppression mediated by increased IL-10 and decreased IL-6 expression.

  16. Interferon-τ increases BoLA-I for implantation during early pregnancy in dairy cows

    PubMed Central

    Zhu, Zhe; Li, Binbin; Wu, Yue; Wang, Xiao; Deng, GanZhen

    2017-01-01

    Interferon-τ (IFN-τ) signals pregnancy recognition in ruminants. We investigated the effects of IFN-τ produced by embryo trophoblastic cells (ETCs) on expression of bovine leukocyte antigen-I (BoLA-I), a bovine analogue of human MHC-I, in endometrial luminal epithelial cells (EECs) during early pregnancy in dairy cows. Expression of IFN-τ and BoLA-I was increased in endometrial tissues during early pregnancy. Expression of the anti-inflammatory cytokine IL-10 was increased in endometrial tissues, while expression of the pro-inflammatory cytokine IL-6 was decreased, indicating immunosuppression. Progesterone increased IFN-τ expression in EECs. IFN-τ increased p-STAT1 and p-STAT3 levels in EECs, but reduced TRAF3 levels. In addition, IFN-τ increased expression of BoLA-I and IL-10, but decreased expression of IL-6 in EECs. These results indicate that IFN-τ enables stable implantation in dairy cows by increasing expression of BoLA-I, and by immunosuppression mediated by increased IL-10 and decreased IL-6 expression. PMID:29221114

  17. A new approach to implant alignment and ligament balancing in total knee arthroplasty focussing on joint loads.

    PubMed

    Zimmermann, Frauke; Schwenninger, Christoph; Nolten, Ulrich; Firmbach, Franz Peter; Elfring, Robert; Radermacher, Klaus

    2012-05-06

    Preservation and recovery of the mechanical leg axis as well as good rotational alignment of the prosthesis components and well-balanced ligaments are essential for the longevity of total knee arthroplasty (TKA). In the framework of the OrthoMIT project, the genALIGN system, a new navigated implantation approach based on intra-operative force-torque measurements, has been developed. With this system, optical or magnetic position tracking as well as any fixation of invasive rigid bodies are no longer necessary. For the alignment of the femoral component along the mechanical axis, a sensor-integrated instrument measures the torques resulting from the deviation between the instrument's axis and the mechanical axis under manually applied axial compression load. When both axes are coaxial, the resulting torques equal zero, and the tool axis can be fixed with respect to the bone. For ligament balancing and rotational alignment of the femoral component, the genALIGN system comprises a sensor-integrated tibial trial inlay measuring the amplitude and application points of the forces transferred between femur and tibia. Hereby, the impact of ligament tensions on knee joint loads can be determined over the whole range of motion. First studies with the genALIGN system, including a comparison with an imageless navigation system, show the feasibility of the concept.

  18. The role of dental implant abutment design on the aesthetic outcome: preliminary 3-month post-loading results from a multicentre split-mouth randomised controlled trial comparing two different abutment designs.

    PubMed

    Esposito, Marco; Cardaropoli, Daniele; Gobbato, Luca; Scutellà, Fabio; Fabianelli, Andrea; Mascellani, Saverio; Delli Ficorelli, Gianluca; Mazzocco, Fabio; Sbricoli, Luca; Trullenque-Eriksson, Anna

    To evaluate whether there are aesthetic and clinical benefits to using a newly designed abutment (Curvomax), over a conventional control abutment (GingiHue). A total of 49 patients, who required at least two implants, had two sites randomised according to a split-mouth design to receive one abutment of each type at seven different centres. The time of loading (immediate, early or delayed) and of prosthesis (provisional crowns of fixed prosthesis) was decided by the clinicians, but they had to restore both implants in a similar way. Provisional prostheses were replaced by definitive ones 3 months after initial loading, when the follow-up for the initial part of this study was completed. Outcome measures were: prosthesis failures, implant failures, complications, pink esthetic score (PES), peri-implant marginal bone level changes, and patient preference. In total, 49 Curvomax and 49 GingiHue abutments were delivered. Two patients dropped out. No implant failure, prosthesis failure or complication was reported. There were no differences at 3 months post-loading for PES (difference = -0.15, 95% CI -0.55 to 0.25; P (paired t test) = 0.443) and marginal bone level changes (difference = -0.02 mm, 95% CI -0.20 to 0.16; P (paired t test) = 0.817). The majority of the patients (30) had no preference regarding the two abutment designs; 11 patients preferred the Curvomax, while five patients preferred the GingiHue abutments (P (McNemar test) = 0.210). The preliminary results of the comparison between two different abutment designs did not disclose any statistically significant differences between the evaluated abutments. However the large number of missing radiographs and clinical pictures casts doubt on the reliability of the results. Longer follow-ups of wider patient populations are needed to better understand whether there is an effective advantage with one of the two abutment designs. Conflict of interest statement: This research project was originally partially funded by

  19. Reducing radiation exposure during CRT implant procedures: early experience with a sensor-based navigation system.

    PubMed

    Thibault, Bernard; Andrade, Jason G; Dubuc, Marc; Talajic, Mario; Guerra, Peter G; Dyrda, Katia; Macle, Laurent; Rivard, Léna; Roy, Denis; Mondésert, Blandine; Khairy, Paul

    2015-01-01

    Cardiac resynchronization therapy (CRT) implant procedures are often complex and prolonged, resulting in significant ionizing radiation (IR) exposure to the patient and operator. We report our early experience working with a novel sensor-based electromagnetic tracking system (MediGuide™, MDG, St. Jude Medical Inc., St. Paul, MN, USA), in terms of procedural IR exposure reduction. Information regarding patient demographics, procedural details, procedural duration, and IR exposure were prospectively collected on 130 consecutive CRT procedures performed between January 2013 and January 2014. Sixty procedures were performed with MDG guidance, and 70 were performed without MDG guidance. Despite a nonsignificant trend toward shorter procedure duration with the use of MDG (120 minutes vs 138 minutes with non-MDG, P = 0.088), a 66% reduction in total IR exposure (median 769 μGray · m(2) vs 2,608 μGray · m(2), P < 0.001) was found. This reduction was primarily driven by a >90% reduction in IR dose required to cannulate the coronary sinus (median 80 μGray · m(2) vs 922 μGray · m(2), P < 0.001), and to a lesser extent from a reduction in IR dose required for LV lead placement (median 330 μGray·m(2) vs 737 μGray · m(2), P = 0.059). In addition, a significant learning curve effect was observed with a significantly shorter procedural duration for the last 15 cases compared to the first 15 cases (median 98 minutes vs 175 minutes, P < 0.001). The nonfluoroscopic MDG positioning system is associated with a dramatic reduction in exposure to IR during CRT implant procedures, with a 90% decrease in the IR dose required to cannulate the coronary sinus. A steep learning curve was quantified. ©2014 Wiley Periodicals, Inc.

  20. Clinical Management of Implant Prostheses in Patients with Bruxism

    PubMed Central

    Komiyama, Osamu; Lobbezoo, Frank; De Laat, Antoon; Iida, Takashi; Kitagawa, Tsuyoshi; Murakami, Hiroshi; Kato, Takao; Kawara, Misao

    2012-01-01

    There is general agreement that excessive stress to the bone-implant interface may result in implant overload and failure. Early failure of the implant due to excessive loading occurs shortly after uncovering the implant. Excess load on a final restoration after successful implant integration can result in physical failure of the implant structure. Many clinicians believe that overload of dental implants is a risk factor for vertical peri-implant bone loss and/or may be detrimental for the suprastructure in implant prostheses. It has been documented that occlusal parafunction, such as, bruxism (tooth grinding and clenching) affects the outcome of implant prostheses, but there is no evidence for a causal relation between the failures and overload of dental implants. In spite of this lack of evidence, often metal restorations are preferred instead of porcelain for patients in whom bruxism is presumed on the basis of tooth wear. The purpose of this paper is to discuss the importance of the occlusal scheme used in implant restorations for implant longevity and to suggest a clinical approach and occlusal materials for implant prostheses in order to prevent complications related to bruxism. PMID:22701484

  1. [Study on the factors impacting on early cochlear implantation between the eastern and western region of China].

    PubMed

    Xiao, Hanqiong; Li, Wei; Ma, Ruixia; Gong, Zhengpeng; Shi, Haibo; Li, Huawei; Chen, Bing; Jiang, Ye; Dai, Chunfu

    2015-06-01

    To describe tne regional different factors which impact on early cochlear implantation in prelingual deaf children between eastern and western regions of China. The charts of 113 children who received the cochlear implantation after 24 months old were reviewed and analyzed. Forty-five of them came from the eastern region (Jiangsu, Zhejiang or Shanghai) while 68 of them came from the western region (Ningxia or Guizhou). Parental interviews were conducted to collect information regarding the factors that impact on early cochlear implantation. Result:Based on the univariate logistic regression analysis, the odds ratio (OR) value of universal newborn hearing screening (UNHS) was 5. 481, which indicated the correlation of UNHS with early cochlear implantation is significant. There was statistical difference between the 2 groups (P<0. 01). For the financial burden, the OR value was 3. 521(strong correlation) and there was statistical difference between the 2 groups (P<0. 01). For the communication barriers and community location, the OR value was 0. 566 and 1. 128 respectively, and there was no statistical difference between the 2 groups (P>0. 05). The multivariate analysis indicated that the UNHS and financial burden are statistically different between the eastern and western regions (P=0. 00 and 0. 040 respectively). The UNHS and financial burden are statistically different between the eastern reinforced in the western region. In addition, the government and society should provide powerful policy and more financial support in the western region of China. The innovation of management system is also helpful to the early cochlear implantation.

  2. Early Postimplant Speech Perception and Language Skills Predict Long-Term Language and Neurocognitive Outcomes Following Pediatric Cochlear Implantation

    PubMed Central

    Kronenberger, William G.; Castellanos, Irina; Pisoni, David B.

    2017-01-01

    Purpose We sought to determine whether speech perception and language skills measured early after cochlear implantation in children who are deaf, and early postimplant growth in speech perception and language skills, predict long-term speech perception, language, and neurocognitive outcomes. Method Thirty-six long-term users of cochlear implants, implanted at an average age of 3.4 years, completed measures of speech perception, language, and executive functioning an average of 14.4 years postimplantation. Speech perception and language skills measured in the 1st and 2nd years postimplantation and open-set word recognition measured in the 3rd and 4th years postimplantation were obtained from a research database in order to assess predictive relations with long-term outcomes. Results Speech perception and language skills at 6 and 18 months postimplantation were correlated with long-term outcomes for language, verbal working memory, and parent-reported executive functioning. Open-set word recognition was correlated with early speech perception and language skills and long-term speech perception and language outcomes. Hierarchical regressions showed that early speech perception and language skills at 6 months postimplantation and growth in these skills from 6 to 18 months both accounted for substantial variance in long-term outcomes for language and verbal working memory that was not explained by conventional demographic and hearing factors. Conclusion Speech perception and language skills measured very early postimplantation, and early postimplant growth in speech perception and language, may be clinically relevant markers of long-term language and neurocognitive outcomes in users of cochlear implants. Supplemental materials https://doi.org/10.23641/asha.5216200 PMID:28724130

  3. Temporary implant-supported prosthesis for immediate loading according to a chair-side concept: technical note and results from 37 consecutive cases.

    PubMed

    Ostman, Pär-Olov; Hellman, Mats; Sennerby, Lars; Wennerberg, Ann

    2008-05-01

    During the last years, focus has been paid to implant treatment using immediate function protocols, and different approaches to provide patients with temporary constructions have been presented. Most of these techniques involve dental technicians producing the temporary construction, for example, rebuilding existing dentures, acrylic bridges, etc. The purpose of this prospective clinical study was to evaluate the clinical outcome of a chair-side technique of a cost-effective temporary prosthesis. Fixture survival rate and risk of temporary bridge failure were analyzed. Thirty-seven partially or totally edentate patients (18 female and 19 male; mean age: 66.7 years) treated with chair-side manufactured temporary restorations (QuickBridge, BIOMET 3i, Palm Beach, Fl, USA) for immediate loading have been evaluated. The prostheses extended from two unit bridges supported by two implants to full-arch construction supported by six implants. The temporary prostheses were monitored from the day of surgery and delivery to the time of replacement with a permanent prosthetic construction 3 to 6 months later. No implants were lost during the observation time. One (3%) temporary prosthesis fractured and additional two (6%) loosened during the follow-up time. The study indicated that the tested chair-side concept for manufacturing of temporary prosthesis for immediate loading of dental implants is a viable approach.

  4. Fracture load of complete-arch implant-supported prostheses reinforced with nylon-silica mesh: An in vitro study.

    PubMed

    Gonçalves, Fernanda de Cássia Papaiz; Amaral, Marina; Borges, Alexandre Luiz Souto; Gonçalves, Luiz Fernando Martins; Paes-Junior, Tarcisio José de Arruda

    2018-04-01

    Complete-arch implant-supported prostheses without a framework have a high risk of failure: a straightforward and inexpensive reinforcement material, such as nylon mesh, could improve their longevity. The purpose of this in vitro study was to evaluate a nylon-silica mesh compound on the fracture strength of acrylic resin and the fracture load of complete-arch implant-supported prostheses. Twenty-four complete mandibular arch implant-supported prostheses were divided into 2 groups according to cantilever length (molar and premolar) and subdivided into another 2 subgroups according to the presence or absence of reinforcing mesh. The specimens were submitted to a maximum load-to-fracture test in a universal testing machine, with a 100-N load cell, a 2 mm/min crosshead speed, and a spherical metal tip diameter of 4 mm at different points (molar and premolar). These were submitted to 1-way analysis of variance for repeated measurement and the post hoc Tukey multiple comparison test (α=.05). The mean maximum load ±standard deviation for the molar group was 393.4 ±95.0 N with reinforcement and 305.4 ±76.3 N without reinforcement (P=.02); and for the premolar group was 1083.3 ±283.7 N with reinforcement and 605.3 ±90.5 N without reinforcement (P=.001). Reinforcement with nylon mesh increased the mean maximum load of implant-supported complete-arch prostheses at both cantilever lengths. The cantilever to the premolar (5 mm) presented the highest maximum load values to fracture. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  5. Stability of implants placed in fresh sockets versus healed alveolar sites: Early findings.

    PubMed

    Gehrke, Sergio Alexandre; da Silva Neto, Ulisses Tavares; Rossetti, Paulo Henrique Orlato; Watinaga, Sidney Eiji; Giro, Gabriela; Shibli, Jamil Awad

    2016-05-01

    The present study measured implant stability quotient (ISQ) values at three different time points after surgical procedures to compare whether the stability values differed between implants placed in fresh extraction sockets versus healed alveolar sites. To measure implant stability, resonance frequency analysis (RFA) was performed in 77 patients (53 women, 24 men) with a total of 120 dental implants. These implants were divided into two groups: Group 1 included 60 implants in healed alveolar sites (22 in the maxilla, 38 in the mandible), and Group 2 included 60 implants in fresh sockets (41 in the maxilla, 19 in the mandible). Implant stability was measured immediately at implant placement (baseline), 90, and 150 days later. Statistical analysis was made using a multivariate regression linear model at implant level (α = 0.05). Overall, the means and standard deviations of the ISQ values were 62.7 ± 7.14 (95% confidence interval [CI], 39-88) at baseline, 70.0 ± 6.22 (95% CI, 46-88) at 90 days, and 73.4 ± 5.84 (95% CI, 58-88) at 150 days. In Group 1, the ISQs ranged between 64.3 ± 6.20 and 75.0 ± 5.69, while in Group 2, presented lower values that ranged between 61.2 ± 8.09 and 71.9 ± 5.99 (P = 0.002). Anatomic location and times periods were the only identified variables with an influence on ISQ values at implant level (P < 0.0001). The stabilities of the implants placed in the fresh sockets and in healed sites exhibited similar evolutions in ISQ values and thus osseointegration; however, the implants in the healed alveolar sites exhibited superior values at all time points. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Imunohistological aspects of the tissue around dental implants

    NASA Astrophysics Data System (ADS)

    Nimigean, Victor; Nimigean, Vanda R.; Sǎlǎvǎstru, Dan I.; Moraru, Simona; BuÅ£incu, Lavinia; Ivaşcu, Roxana V.; Poll, Alexandru

    2016-03-01

    Objectives: study of soft and hard tissues around implants. Material and methods: For the immunohistochemical and histological study of the implant/soft tissue interface, we examined pieces of peri-implant mucosa harvested from 35 patients. The implant/bone interface was assessed using histologic and histomorphometric examination of hard tissues around unloaded, early loaded or delayed loaded dental implants with pre-established design, with a sandblasted and acid-etched surface, placed both in extraction sockets, or after bone healing following tooth removal. This study was performed on 9 common race dogs. Results: The histological study of the implant/soft tissue interface showed regenerative modifications and moderate chronic subepithelial inflammatory reactions. Immunohistochemical evaluation of the soft tissue biopsies revealed the presence of specific immunocompetent cells and proteins of the matrix metalloproteinase (MMP) expression. Bone-implants contacts were more obvious in the apical half of the implants and at the edges of the threads, than between them. A mature, lamelliform bone containing lacunae with osteocytes and lack of connective tissue were noticed around implants that were late placed and loaded. The new-formed bone was also abundant in the crestal zone, not only in the apical part of the implants. Conclusions: A thorough understanding of the microstructure of dental implant/soft and hard tissue interface will improve the longevity of osseointegrated implants.

  7. Does the presence of a Caesarean section scar affect implantation site and early pregnancy outcome in women attending an early pregnancy assessment unit?

    PubMed

    Naji, O; Wynants, L; Smith, A; Abdallah, Y; Saso, S; Stalder, C; Van Huffel, S; Ghaem-Maghami, S; Van Calster, B; Timmerman, D; Bourne, T

    2013-06-01

    Are there any differences in the location and distance to the internal cervical ostium of the implantation site of the intrauterine gestation sacs, early pregnancy symptoms and pregnancy outcome at 12 weeks gestation between women with and without a previous Caesarean section (CS)? The presence of a CS scar affects the site of implantation, and the distance between implantation site and the scar is related to the risk of spontaneous abortion. WHAT IS KNOWN ALREADY?: Little is known about the impact of a CS scar on implantation other than the risk of Caesarean scar pregnancy (CSP). Furthermore, there is a paucity of information on how the proximity of implantation to the scar impacts on pregnancy outcome in the first trimester. A prospective cohort study conducted over 15 months in the early pregnancy unit of a London Teaching Hospital. Three hundred and eighty women underwent a transvaginal scan at 6-11 weeks of gestation. A total of 170 women had undergone ≥1 CS, and 210 women had no history of CS. The 380 women were recruited as consecutive non-selected cases. The relationship between the implanted sac and the CS scar was assessed by quantifiable measures and by subjective impression. Logistic regression analysis was used to determine the influence of the presence of a CS scar on pregnancy outcome. The final outcome of the study was the viability of the pregnancy at 12 weeks. Implantation was most frequently posterior (53%) in the CS group and fundal in the non-CS group (42%). Gestation sac implantation was 8.7 mm lower in the CS group (95% confidence interval (CI) 6.7-10.7, P < 0.0001). Presenting complaints differed in women with and without a previous CS (P = 0.0009). More frequent vaginal bleeding [73 versus 55%, difference -18, 95% CI (-27 to -8%] yet no clearly increased spontaneous abortion rates were noted in the CS group compared with the non-CS group (adjusted odds ratio = 1.1, 95% CI 0.6-1.9, P = 0.74). Subjective impression showed that in eight

  8. Circumferential bone loss around splinted and nonsplinted immediately loaded implants retaining mandibular overdentures: A randomized controlled clinical trial using cone beam computed tomography.

    PubMed

    Elsyad, Moustafa Abdou; Khirallah, Ahmed Samir

    2016-11-01

    Circumferential marginal bone around 2 splinted and nonsplinted immediately loaded implants in the edentulous mandible has not been previously investigated. The purpose of this randomized controlled clinical trial was to assess circumferential bone loss around splinted and nonsplinted immediately loaded implants retaining mandibular overdentures, using cone beam computed tomography (CBCT). Thirty participants with complete edentulism were allocated to 2 groups and received 2 implants in the canine region of the mandible. Implants were either left nonsplinted (with ball attachment [BA]) or splinted (with bar attachment [RA]). Mandibular overdentures were connected to the implants 1 week later. CBCT was used to evaluate vertical bone loss (VBL) and horizontal bone loss (HBLo) bone loss at the distal (D), buccal (B), mesial (M), and lingual (L) sites of each implant upon overdenture insertion (baseline, T0), 1 year (T1) and 3 years (T3) after insertion. Repeated measures ANOVA was used for statistical analysis (α=.05). No significant difference in the survival rate (93.3% for BA and 100% for RA) was found between groups (P=.156). VBL and HBLo increased significantly at T3 compared with T1 for both groups (P<.005). After 3 years, VBL were 1.36 ±0.57 mm and 1.0 ±0.44 mm and HBLo were 0.88 ±0.48 mm for BA and 0.77 ±0.53 mm for RA. At T1 and T3, BA had more significant VBL than RA (P<.001), while HBLo did not differ significantly between groups. For both groups, a significant difference was found in VBL and HBLo between implant sites (P<.001). The B site recorded the highest VBL, and the L site recorded the lowest VBL. The M and D sites recorded the highest HBLo, and the B and L sites recorded the lowest HBLo. Two nonsplinted immediately loaded implants retaining mandibular overdentures were associated with significantly higher vertical and horizontal circumferential bone loss than those associated with splinted implants after a follow-up of 3 years. Copyright

  9. Chemotherapy drug extravasation in totally implantable venous access port systems: how effective is early surgical lavage?

    PubMed

    Azaïs, Henri; Bresson, Lucie; Bassil, Alfred; Katdare, Ninad; Merlot, Benjamin; Houpeau, Jean-Louis; El Bedoui, Sophie; Meurant, Jean-Pierre; Tresch, Emmanuelle; Narducci, Fabrice

    2015-01-01

    Totally implantable venous access port systems (TIVAPS) are a widely used and an essential tool in the efficient delivery of chemotherapy. Chemotherapy drug extravasation (CDE) can have dire consequences and will delay treatment. The purpose of this study is to both clarify the management of CDE and show the effectiveness of early surgical lavage (ESL). Patients who had presented to the Cancer Center of Lille (France) with TIVAPS inserted between January 2004 and April 2013 and CDE had their medical records reviewed retrospectively. Thirty patients and 33 events were analyzed. Implicated agents were vesicants (51.5%), irritants (45.5%) and non-vesicants (3%). Huber needle malpositionning was involved in 27 cases. Surgery was performed in 97% of cases, 87.5% of which were for ESL with 53.1% of the latter requiring TIVAPS extraction. Six patients required a second intervention due to adverse outcomes (severe cases). Vesicants were found to be implicated in four out of six severe cases and oxaliplatin in two others. Extravasated volume was above 50 ml in 80% of cases. Only one patient required a skin graft. CDEs should be managed in specialized centers. ESL allows for limited tissue contact of the chemotherapy drug whilst using a simple, widely accessible technique. The two main factors that correlate with adverse outcome seem to be the nature of the implicated agent (vesicants) and the extravasated volume (above 50 ml) leading to worse outcomes. Oxaliplatin should be considered as a vesicant.

  10. Drilling dimension effects in early stages of osseointegration and implant stability in a canine model

    PubMed Central

    Baires-Campos, Felipe-Eduardo; Jimbo, Ryo; Fonseca-Oliveira, Maiolino-Thomaz; Moura, Camila; Zanetta-Barbosa, Darceny; Coelho, Paulo-Guilherme

    2015-01-01

    Background This study histologically evaluated two implant designs: a classic thread design versus another specifically designed for healing chamber formation placed with two drilling protocols. Material and Methods Forty dental implants (4.1 mm diameter) with two different macrogeometries were inserted in the tibia of 10 Beagle dogs, and maximum insertion torque was recorded. Drilling techniques were: until 3.75 mm (regular-group); and until 4.0 mm diameter (overdrilling-group) for both implant designs. At 2 and 4 weeks, samples were retrieved and processed for histomorphometric analysis. For torque and BIC (bone-to-implant contact) and BAFO (bone area fraction occupied), a general-linear model was employed including instrumentation technique and time in vivo as independent. Results The insertion torque recorded for each implant design and drilling group significantly decreased as a function of increasing drilling diameter for both implant designs (p<0.001). No significant differences were detected between implant designs for each drilling technique (p>0.18). A significant increase in BIC was observed from 2 to 4 weeks for both implants placed with the overdrilling technique (p<0.03) only, but not for those placed in the 3.75 mm drilling sites (p>0.32). Conclusions Despite the differences between implant designs and drilling technique an intramembranous-like healing mode with newly formed woven bone prevailed. Key words: Histomorphometry, biomechanical, in vivo, initial stability, insertion torque, osseointegration. PMID:25858087

  11. Assessing the Effect of Dental Implants Thread Design on Distribution of Stress in Impact Loadings Using Three Dimensional Finite Element Method

    PubMed Central

    I, Zarei; S, Khajehpour; A, Sabouri; AZ, Haghnegahdar; K, Jafari

    2016-01-01

    Statement of Problem: Impacts and accidents are considered as the main fac- tors in losing the teeth, so the analysis and design of the implants that they can be more resistant against impacts is very important. One of the important nu- merical methods having widespread application in various fields of engineering sciences is the finite element method. Among its wide applications, the study of distribution of power in complex structures can be noted. Objectives: The aim of this research was to assess the geometric effect and the type of implant thread on its performance; we also made an attempt to determine the created stress using finite element method. Materials and Methods: In this study, the three dimensional model of bone by using Cone Beam Computerized Tomography (CBCT) of the patient has been provided. The implants in this study are designed by Solid Works software. Loading is simulated in explicit dynamic, by struck of a rigid body with the speed of 1 mm/s to implant vertically and horizontally; and the maximum level of induced stress for the cortical and trabecular bone in the ANSYS Workbench software was calculated. Results: By considering the results of this study, it was identified that, among the designed samples, the maximum imposed stress in the cortical bone layer occurred in the first group (straight threads) and the maximum stress value in the trabecular bone layer and implant occurred in the second group (tapered threads). Conclusions: Due to the limitations of this study, the implants with more depth thread, because of the increased contact surface of the implant with the bone, caused more stability; also, the implant with smaller thread and shorter pitch length caused more stress to the bone. PMID:28959748

  12. Assessing the Effect of Dental Implants Thread Design on Distribution of Stress in Impact Loadings Using Three Dimensional Finite Element Method.

    PubMed

    I, Zarei; S, Khajehpour; A, Sabouri; Az, Haghnegahdar; K, Jafari

    2016-06-01

    Impacts and accidents are considered as the main fac- tors in losing the teeth, so the analysis and design of the implants that they can be more resistant against impacts is very important. One of the important nu- merical methods having widespread application in various fields of engineering sciences is the finite element method. Among its wide applications, the study of distribution of power in complex structures can be noted. The aim of this research was to assess the geometric effect and the type of implant thread on its performance; we also made an attempt to determine the created stress using finite element method. In this study, the three dimensional model of bone by using Cone Beam Computerized Tomography (CBCT) of the patient has been provided. The implants in this study are designed by Solid Works software. Loading is simulated in explicit dynamic, by struck of a rigid body with the speed of 1 mm/s to implant vertically and horizontally; and the maximum level of induced stress for the cortical and trabecular bone in the ANSYS Workbench software was calculated. By considering the results of this study, it was identified that, among the designed samples, the maximum imposed stress in the cortical bone layer occurred in the first group (straight threads) and the maximum stress value in the trabecular bone layer and implant occurred in the second group (tapered threads). Due to the limitations of this study, the implants with more depth thread, because of the increased contact surface of the implant with the bone, caused more stability; also, the implant with smaller thread and shorter pitch length caused more stress to the bone.

  13. Combination of Heel-strike like Mechanical Loading with Deproteinized Cancellous Bone Scaffold Implantation to Repair Segmental Bone Defects in Rabbits.

    PubMed

    Huang, Guofeng; Liu, Guojun; Zhang, Feng; Gao, Jianting; Wang, Jiangze; Chen, Qi; Wu, Benwen; Ding, Zhenqi; Cai, Taoyi

    2017-01-01

    Under physiological conditions bone defects often occur at mechanical load bearing sites and bone substitutes used for regeneration should be similarly subjected to mechanical loading stress. In this study, we investigated whether a novel heel-strike like mechanical loading method can be used as a complementary therapy to promote bone regeneration following bone substitute grafting. To test this, three groups of rabbits with segmental bone defects in the tibia were implanted with bovine deproteinized cancellous bone scaffold (DCBS), with one group also receiving heel-strike like mechanical loading generated by a rap stress stimulator. From weeks 4-12 post-operation X-ray and micro-CT scanning showed that rabbits receiving combination therapy had significantly more callus at the bone defect. Moreover, bone defects in the combination group were completely replaced with new bone at week 12, while the DCBS implantation alone group healed only partially and rabbits receiving neither DCBS nor mechanical loading developed only small calluses throughout the observation period. Analysis of micro-CT scanning results demonstrated that new bone density in the combination group was significantly higher than the DCBS only group at weeks 4 and 12 ( p <0.05). H&E staining results also indicated a significantly higher percentage of new bone in the bone defect area and a lower percentage of residual scaffold in the combination group compared to the DCBS only group ( p <0.05). Thus, this heel-strike like mechanical loading method appears to accelerate bone regeneration following substitute implantation by restoring a local mechanical loading environment in segmental bone defects.

  14. Influence of rhBMP-2 on Guided Bone Regeneration for Placement and Functional Loading of Dental Implants: A Radiographic and Histologic Study in Dogs.

    PubMed

    Ben Amara, Heithem; Lee, Jung-Won; Kim, Jung-Ju; Kang, Yun-Mi; Kang, Eun-Jung; Koo, Ki-Tae

    Evidence on the outcomes of functional loading placed in recombinant human bone morphogenetic protein 2 (rhBMP-2)/acellular collagen sponge (ACS)-induced bone is lacking. The aim of this study was to verify whether guided bone regeneration (GBR) with rhBMP-2/ACS enhances regeneration of missing bone and osseointegration of dental implants subject to functional loading. Two bilateral standardized large saddle-type defects (≈10 × 10 × 6 mm) were surgically created in each mandible of seven beagle dogs 2 months after tooth extraction. Defects were immediately reconstructed randomly using rhBMP-2 (O-BMP or InFuse) soaked in ACS, deproteinized bovine bone mineral (DBBM) granules, or ACS alone as surgical control and subsequently covered with collagen membrane. Screw-type sand-blasted, acid-etched dental implants were placed 3 months later into the reconstructed defects and into adjacent bone. Osseointegration was allowed to progress for 3 months before functional loading of 3 months until sacrifice. Significantly more bone fill was radiographically observed for GBR with rhBMP-2/ACS (O-BMP: 92.5%, InFuse: 79%) in comparison to the DBBM (52%) and ACS alone groups (56.6%). Osseointegration was achieved and maintained in all experimental defects challenged by prostheses-driven functional load. The bone density ranged from 37.49% in the ACS group to 64.9% in the rhBMP-2/ACS (InFuse) group with no significance. The highest mean percentage of BIC was found in rhBMP-2/ACS (InFuse: 52.98%) with no statistical difference. Crestal bone resorption was observed around implants placed in reconstructed areas without any significant difference. GBR with rhBMP-2/ACS provided the greatest bone fill among the three treatment procedures. GBR with rhBMP-2/ACS showed efficacy for placement, osseointegration, and functional loading of titanium implants in alveolar ridge defects.

  15. A new platelet cryoprecipitate glue promoting bone formation after ectopic mesenchymal stromal cell-loaded biomaterial implantation in nude mice.

    PubMed

    Trouillas, Marina; Prat, Marie; Doucet, Christelle; Ernou, Isabelle; Laplace-Builhé, Corinne; Blancard, Patrick Saint; Holy, Xavier; Lataillade, Jean-Jacques

    2013-01-04

    This study investigated the promising effect of a new Platelet Glue obtained from Cryoprecipitation of Apheresis Platelet products (PGCAP) used in combination with Mesenchymal Stromal Cells (MSC) loaded on ceramic biomaterials to provide novel strategies enhancing bone repair. PGCAP growth factor content was analyzed by ELISA and compared to other platelet and plasma-derived products. MSC loaded on biomaterials (65% hydroxyapatite/35% beta-TCP or 100% beta-TCP) were embedded in PGCAP and grown in presence or not of osteogenic induction medium for 21 days. Biomaterials were then implanted subcutaneously in immunodeficient mice for 28 days. Effect of PGCAP on MSC was evaluated in vitro by proliferation and osteoblastic gene expression analysis and in vivo by histology and immunohistochemistry. We showed that PGCAP, compared to other platelet-derived products, allowed concentrating large amount of growth factors and cytokines which promoted MSC and osteoprogenitor proliferation. Next, we found that PGCAP improves the proliferation of MSC and osteogenic-induced MSC. Furthermore, we demonstrated that PGCAP up-regulates the mRNA expression of osteogenic markers (Collagen type I, Osteonectin, Osteopontin and Runx2). In vivo, type I collagen expressed in ectopic bone-like tissue was highly enhanced in biomaterials embedded in PGCAP in the absence of osteogenic pre-induction. Better results were obtained with 65% hydroxyapatite/35% beta-TCP biomaterials as compared to 100% beta-TCP. We have demonstrated that PGCAP is able to enhance in vitro MSC proliferation, osteoblastic differentiation and in vivo bone formation in the absence of osteogenic pre-induction. This clinically adaptable platelet glue could be of interest for improving bone repair.

  16. A new platelet cryoprecipitate glue promoting bone formation after ectopic mesenchymal stromal cell-loaded biomaterial implantation in nude mice

    PubMed Central

    2013-01-01

    Introduction This study investigated the promising effect of a new Platelet Glue obtained from Cryoprecipitation of Apheresis Platelet products (PGCAP) used in combination with Mesenchymal Stromal Cells (MSC) loaded on ceramic biomaterials to provide novel strategies enhancing bone repair. Methods PGCAP growth factor content was analyzed by ELISA and compared to other platelet and plasma-derived products. MSC loaded on biomaterials (65% hydroxyapatite/35% beta-TCP or 100% beta-TCP) were embedded in PGCAP and grown in presence or not of osteogenic induction medium for 21 days. Biomaterials were then implanted subcutaneously in immunodeficient mice for 28 days. Effect of PGCAP on MSC was evaluated in vitro by proliferation and osteoblastic gene expression analysis and in vivo by histology and immunohistochemistry. Results We showed that PGCAP, compared to other platelet-derived products, allowed concentrating large amount of growth factors and cytokines which promoted MSC and osteoprogenitor proliferation. Next, we found that PGCAP improves the proliferation of MSC and osteogenic-induced MSC. Furthermore, we demonstrated that PGCAP up-regulates the mRNA expression of osteogenic markers (Collagen type I, Osteonectin, Osteopontin and Runx2). In vivo, type I collagen expressed in ectopic bone-like tissue was highly enhanced in biomaterials embedded in PGCAP in the absence of osteogenic pre-induction. Better results were obtained with 65% hydroxyapatite/35% beta-TCP biomaterials as compared to 100% beta-TCP. Conclusions We have demonstrated that PGCAP is able to enhance in vitro MSC proliferation, osteoblastic differentiation and in vivo bone formation in the absence of osteogenic pre-induction. This clinically adaptable platelet glue could be of interest for improving bone repair. PMID:23290259

  17. Degradation of Zr-based bulk metallic glasses used in load-bearing implants: A tribocorrosion appraisal.

    PubMed

    Zhao, Guo-Hua; Aune, Ragnhild E; Mao, Huahai; Espallargas, Nuria

    2016-07-01

    Owing to the amorphous structure, Bulk Metallic Glasses (BMGs) have been demonstrating attractive properties for potential biomedical applications. In the present work, the degradation mechanisms of Zr-based BMGs with nominal compositions Zr55Cu30Ni5Al10 and Zr65Cu18Ni7Al10 as potential load-bearing implant material were investigated in a tribocorrosion environment. The composition-dependent micro-mechanical and tribological properties of the two BMGs were evaluated prior to the tribocorrosion tests. The sample Zr65-BMG with a higher Zr content exhibited increased plasticity but relatively reduced wear resistance during the ball-on-disc tests. Both BMGs experienced abrasive wear after the dry wear test under the load of 2N. The cross-sectional subsurface structure of the wear track was examined by Focused Ion Beam (FIB). The electrochemical properties of the BMGs in simulated body fluid were evaluated by means of potentiodynamic polarization and X-ray Photoelectron Spectroscopy (XPS). The spontaneous passivation of Zr-based BMGs in Phosphate Buffer Saline solution was mainly attributed to the highly concentrated zirconium cation (Zr(4+)) in the passive film. The tribocorrosion performance of the BMGs was investigated using a reciprocating tribometer equipped with an electrochemical cell. The more passive nature of the Zr65-BMG had consequently a negative influence on its tribocorrosion resistance, which induced the wear-accelerated corrosion and eventually speeded-up the degradation process. It has been revealed the galvanic coupling was established between the depassivated wear track and the surrounding passive area, which is the main degradation mechanism for the passive Zr65-BMG subjected to the tribocorrosion environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Sustained Zero-Order Release of Intact Ultra-Stable Drug-Loaded Liposomes from an Implantable Nanochannel Delivery System

    PubMed Central

    Celia, Christian; Ferrati, Silvia; Bansal, Shyam; van de Ven, Anne L.; Ruozi, Barbara; Zabre, Erika; Hosali, Sharath; Paolino, Donatella; Sarpietro, Maria Grazia; Fine, Daniel; Fresta, Massimo; Ferrari, Mauro

    2014-01-01

    Metronomic chemotherapy supports the idea that long-term, sustained, constant administration of chemotherapeutics, currently not achievable, could be effective against numerous cancers. Particularly appealing are liposomal formulations, used to solubilize hydrophobic therapeutics and minimize side effects, while extending drug circulation time and enabling passive targeting. As liposome alone cannot survive in circulation beyond 48 hrs, sustaining their constant plasma level for many days is a challenge. To address this, we developed, as a proof of concept, an implantable nanochannel delivery system and ultra-stable PEGylated lapatinib loaded-liposomes, and we demonstrate the release of intact vesicles for over 18 days. Further, we investigate intravasation kinetics of subcutaneously delivered liposomes and verify their biological activity post nanochannel release on BT474 breast cancer cells. The key innovation of this work is the combination of two nanotechnologies to exploit the synergistic effect of liposomes, demonstrated as passive-targeting vectors and nanofluidics to maintain therapeutic constant plasma levels. In principle, this approach could maximize efficacy of metronomic treatments. PMID:23881575

  19. Computer-assisted surgery in the lower jaw: double surgical guide for immediately loaded implants in postextractive sites-technical notes and a case report.

    PubMed

    De Santis, Daniele; Canton, Luciano Claudio; Cucchi, Alessandro; Zanotti, Guglielmo; Pistoia, Enrico; Nocini, Pier Francesco

    2010-01-01

    Computer-assisted surgery is based on computerized tomography (CT) scan technology to plan the placement of dental implants and a computer-aided design/computer-aided manufacturing (CAD-CAM) technology to create a custom surgical template. It provides guidance for insertion implants after analysis of existing alveolar bone and planning of implant position, which can be immediately loaded, therefore achieving esthetic and functional results in a surgical stage. The absence of guidelines to treat dentulous areas is often due to a lack of computer-assisted surgery. The authors have attempted to use this surgical methodology to replace residual teeth with an immediate implantoprosthetic restoration. The aim of this case report is to show the possibility of treating a dentulous patient by applying a computer-assisted surgical protocol associated with the use of a double surgical template: one before extraction and a second one after extraction of selected teeth.

  20. Allostatic Load Assessment for Early Detection of Stress in the Workplace in Egypt.

    PubMed

    Ali, Ola Sayed; Badawy, Nadia; Rizk, Sanaa; Gomaa, Hend; Saleh, Mai Sabry

    2016-09-15

    Workplace stress is hazardous for its harmful impact on employees' health and organizational productivity. The aim of the study is to apply the Allostatic Load Index (ALI) which is a multi-component measure for health risk assessment and early detection of stress among workers in Egypt. Sixty-two working adults randomly selected from two different working environments in Egypt were included in the study. Participants completed a self-reported questionnaire for socio-demographic and work variables. Andrews and Withey test for Job Satisfaction was filled and 3 ml blood samples were collected. Markers assessed for Allostatic Load were serum cortisol, c-reactive protein, dehydroepiandrosterone-sulphate, total thyroxine, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, total cholesterol to high-density lipoprotein ratio, systolic and diastolic blood pressures, waist to hip ratio and body mass index. The risk quartile method was used for calculation of ALI. ALI value of four or more indicates high Allostatic Load. Job satisfaction scale defined about a quarter of the study population (24%) to be dissatisfied with Allostatic Load of 2.4 as the mean value. Population percentage with ALI ≥4 reached 12.9% with 100% of them females. A significant association was found between Allostatic Load of primary mediators and age, the presence of chronic diseases, place of work and female gender. Female gender and the old age of the Egyptian workforce under study are at higher risk of chronic diseases. Using an alternative way -for example, the cut-point method- instead of the risk quartiles for dichotomization of markers used in ALI calculation could be more precise for early detection of stress among healthy individuals.

  1. Early Ahmed Glaucoma Valve Implantation after Penetrating Keratoplasty Leads to Better Outcomes in an Asian Population with Preexisting Glaucoma

    PubMed Central

    Tai, Ming-Cheng; Chen, Yi-Hao; Cheng, Jen-Hao; Liang, Chang-Min; Chen, Jiann-Torng; Chen, Ching-Long; Lu, Da-Wen

    2012-01-01

    Background To evaluate the efficacy of Ahmed Glaucoma Valve (AGV) surgery and the optimal interval between penetrating keratoplasty (PKP) and AGV implantation in a population of Asian patients with preexisting glaucoma who underwent PKP. Methodology/Principal Findings In total, 45 eyes of 45 patients were included in this retrospective chart review. The final intraocular pressures (IOPs), graft survival rate, and changes in visual acuity were assessed to evaluate the outcomes of AGV implantations in eyes in which AGV implantation occurred within 1 month of post-PKP IOP elevation (Group 1) and in eyes in which AGV implantation took place more than 1 month after the post-PKP IOP evaluation (Group 2). Factors that were associated with graft failure were analyzed, and the overall patterns of complications were reviewed. By their final follow-up visits, 58% of the patients had been successfully treated for glaucoma. After the operation, there were no statistically significant differences between the groups with respect to graft survival (p = 0.98), but significant differences for IOP control (p = 0.049) and the maintenance of visual acuity (VA) (p<0.05) were observed. One year after surgery, the success rates of IOP control in Group 1 and Group 2 were 80% and 46.7%, respectively, and these rates fell to 70% and 37.3%, respectively, by 2 years. Factors that were associated with a high risk of AGV failure were a diagnosis of preexisting angle-closure glaucoma, a history of previous PKP, and a preoperative IOP that was >21 mm Hg. The most common surgical complication, aside from graft failure, was hyphema. Conclusions/Significance Early AGV implantation results in a higher probability of AGV survival and a better VA outcome without increasing the risk of corneal graft failure as a result of post-PKP glaucoma drainage tube implantation. PMID:22629464

  2. Simplified procedure for the immediate loading of a complete fixed prosthesis supported by four implants in the maxillary jaw: a 2-year prospective study.

    PubMed

    Piano, Sergio; Romeo, Eugenio; Sbricoli, Luca; Pisoni, Gianluca; Cea, Niccoló; Lops, Diego

    2016-12-01

    The aim of this study was to verify the reliability of a system for the fixed retention of complete maxillary prostheses supported by four implants with a follow-up of 2 years. Patients were treated between September 2009 and December 2010 with four Straumann Bone Level SLActive implants supporting a complete prosthesis (CPs). The two distal implants were positioned mesially to the maxillary sinus and with a mesio-distal inclination ≤ 30° in order to reduce the distal prosthesis cantilever. An immediate loading surgical protocol was used. The CPs were planned to be fixed to multibase abutments to test their retention for a fixed rehabilitation. Clinical and radiographic parameters as probing pocket depth (PPD), bleeding score (mBI), plaque index (PI), and marginal bone loss (MBL) were assessed at a 1- and 2-year follow-up visits. Moreover, any biological and prosthodontic maintenance events were recorded. Clinical and radiographic parameters changes were analyzed. Twenty-one patients treated with a total of 84 implants completed the 2-year examination period. Four patients were lost to follow up. No technical complication was recorded. Also, no implant, reconstruction, or abutment failures were observed. Therefore, an implant and prosthetic survival rate of 100% were achieved after 2 years. The mean periodontal parameter scores after 2 years of function were 2.6 mm for PPD (SD 0.8 mm), 0.3 for mBI (SD 0.5 mm), and 1.2 for PI (SD 0.4 mm) indexes, respectively. In addition, the mean MBL score measured at the 2-year follow-up visit was -0.34 mm (SD of -0.45 mm). Furthermore, no peri-implant soft tissue inflammation or peri-implant infection was observed. It has been shown that immediate loading of four implants positioned anteriorly to the maxillary sinus could be a reliable treatment procedure to support fixed complete restorations. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. The effects of hydroxyapatite coating and bone allograft on fixation of loaded experimental primary and revision implants.

    PubMed

    Søballe, Kjeld; Mouzin, Olivier R G; Kidder, Louis A; Overgaard, Søren; Bechtold, Joan E

    2003-06-01

    We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability for the presence of particulate polyethylene. During this procedure, a sclerotic endosteal bone rim forms, and a dense fibrous membrane is engendered, having macrophages with ingested polyethylene and high levels of inflammatory cytokines. At the time of revision after 8 weeks, the cavity is revised with either a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included in each of the 8 treatment groups (total 64 implants in 32 dogs). The observation period was 4 weeks after revision. Outcome measures are based on histomorphometry and mechanical pushout properties. The revision setting was always inferior to its primary counterpart. Bone graft improved the revision fixation in all treatment groups, as also did the HA coating. The sole exception was revision-grafted HA implants, which reached the same fixation as primary Ti and HA grafted implants. The revision, which was less active in general, seems to need the dual stimulation of bone graft and HA implant surface, to obtain the same level of fixation associated with primary implants. Our findings suggest that the combination of HA implant and bone graft may be of benefit in the clinical revision implant setting.

  4. The effects of hydroxyapatite coating and bone allograft on fixation of loaded experimental primary and revision implants

    PubMed Central

    Søballe, Kjeld; Mouzin, Olivier R G; Kidder, Louis A; Overgaard, Søren; Bechtold, Joan E

    2015-01-01

    We used our established experimental model of revision joint replacement to examine the roles of hydroxyapatite coating and bone graft in improving the fixation of revision implants. The revision protocol uses the Søballe micromotion device in a preliminary 8-week period of implant instability for the presence of particulate polyethylene. During this procedure, a sclerotic endosteal bone rim forms, and a dense fibrous membrane is engendered, having macrophages with ingested polyethylene and high levels of inflammatory cytokines. At the time of revision after 8 weeks, the cavity is revised with either a titanium alloy (Ti) or a hydroxyapatite (HA) 6.0 mm plasma-sprayed implant, in the presence or absence of allograft packed into the initial 0.75 mm peri-implant gap. The contralateral limb is subjected to primary surgery with the same implant configuration, and serves as control. 8 implants were included in each of the 8 treatment groups (total 64 implants in 32 dogs). The observation period was 4 weeks after revision. Outcome measures are based on histomorphometry and mechanical pushout properties. The revision setting was always inferior to its primary counterpart. Bone graft improved the revision fixation in all treatment groups, as also did the HA coating. The sole exception was revision-grafted HA implants, which reached the same fixation as primary Ti and HA grafted implants. The revision, which was less active in general, seems to need the dual stimulation of bone graft and HA implant surface, to obtain the same level of fixation associated with primary implants. Our findings suggest that the combination of HA implant and bone graft may be of benefit in the clinical revision implant setting. PMID:12899541

  5. Changes in general and oral health-related quality of life in immediate or conventionally loaded dental implants: a nonrandomized clinical trial.

    PubMed

    Dolz, Javier; Silvestre, Francisco J; Montero, Javier

    2014-01-01

    To evaluate changes in the general and oral health-related quality of life (using the European Quality of Life indicator and the Oral Health Impact Profile-49 [OHIP-49], respectively) of patients treated with conventionally or immediately loaded implants. This clinical trial consisted of a clinical oral examination and a questionnaire-based interview carried out before and after both surgery and definitive prosthetic rehabilitation in a consecutive sample of patients requiring dental implants. According to the clinical diagnosis and patient preference, patients were assigned to the immediate loading group (IL group; n = 29) or the conventional loading group (CL group; n = 75). The change summary scores and effect sizes were calculated in the intermediate stage and at the final follow-up, taking baseline scores as reference. The oral health-related quality of life and oral satisfaction after implant therapy were significantly better than at baseline, with an even greater benefit when the implants were loaded immediately than when prosthetic rehabilitation was delayed. However, there were no significant differences in between-group comparisons in the ratings of general health status. The effect size for the OHIP-49 exceeded the threshold value of 0.8 for the domains functional limitation, pain/discomfort, and psychological discomfort in both groups and also for physical disability and psychological disability in the IL group. A gradual improvement in oral well-being scores, but not in those of general well-being, were observed for both groups from the intermediate stage to the final evaluation. This benefit was markedly greater for the IL group.

  6. Early experimental and clinical experience with a focal implant for lower extremity post-angioplasty dissection.

    PubMed

    Schneider, Peter A; Giasolli, Robert; Ebner, Adrian; Virmani, Renu; Granada, Juan F

    2015-02-01

    This study provides preliminary data on the safety and feasibility of the use of a novel focal implant for managing post-percutaneous transluminal balloon angioplasty (post-PTA) dissection. Post-PTA dissection of the lower extremity arteries is managed with stent placement. This provides an acceptable post-intervention result but has long-term disadvantages, such as in-stent restenosis. Focal treatment of post-PTA dissection and avoidance of stents are the objectives of the Tack-It (Intact Vascular, Inc., Wayne, Pennsylvania) device. A preclinical study and first-in-human data are presented. Seven swine underwent superficial femoral artery device placement, with a self-expanding nitinol stent on 1 side and a series of 4 Tack-It devices on the other side. Specimens were harvested at 28 days. The clinical study included 15 limbs that underwent revascularization for critical limb ischemia (n = 9) or claudication (n = 6). Twenty-five lesions were treated in the superficial femoral (n = 8), popliteal (n = 7), and tibial (n = 10) arteries. The preclinical study demonstrated a reduction in stenosis with the Tack-It (16.8 ± 2.6%) compared with stents (46.4 ± 9.8%). Neointimal thickness and injury score decreased with the Tack-It. Clinically, Tack-It placement resulted in acute technical success with resolution of the post-PTA dissection in 100% of lesions. There were no device-related complications or major amputations. Eighteen of the 25 lesions were available for angiographic follow-up at 1-year, and patency was 83.3%. Preclinical data suggest that the Tack-It device causes minimal vessel injury. Clinical use of the Tack-It to manage post-PTA dissection was safe and feasible in this early study and resulted in apposition of dissection flaps without stent placement. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  7. Early outcomes of percutaneous pulmonary valve implantation using the Edwards SAPIEN XT transcatheter heart valve system.

    PubMed

    Haas, Nikolaus A; Carere, Ronald Giacomo; Kretschmar, Oliver; Horlick, Eric; Rodés-Cabau, Josep; de Wolf, Daniël; Gewillig, Marc; Mullen, Michael; Lehner, Anja; Deutsch, Cornelia; Bramlage, Peter; Ewert, Peter

    2018-01-01

    Patients with congenital or acquired heart defects affecting the pulmonary valve and right ventricular outflow tract (RVOT) commonly require multiple surgical interventions, resulting in significant morbidity. A less invasive alternative is percutaneous pulmonary valve implantation (PPVI). Though studies have previously reported the safety and efficacy of the early generation transcatheter heart valves (THVs), data on more recent devices are severely lacking. We performed a multinational, multicentre, retrospective, observational registry analysis of patients who underwent PPVI using the Edwards SAPIEN XT THV. Of the 46 patients that were enrolled, the majority had tetralogy of Fallot as the underlying diagnosis (58.7%), and stentless xenograft as the most common RVOT anatomy (34.8%). Procedural success rate was high (93.5%), with a low frequency of periprocedural complications and adverse events (6.5% and 10.9%, respectively). At 30days post-procedure, NYHA class had improved significantly (90.6% were at NYHA I or II). The rate of moderate/severe pulmonary regurgitation had decreased from 76.1% at baseline to 5.0% at 30days, and the calculated peak systolic gradient had decreased from 45.2 (SD±21.3) mmHg to 16.4 (SD±8.0) mmHg, with these values remaining low up to 2years. The data suggest the efficacy and safety of the SAPIEN XT THV in PPVI in common anatomies in patients with conduits, as well as those with native pulmonary valves or transannular patches. Continued data collection is necessary to verify long-term findings. CLINICALTRIALS. NCT02302131. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. In vitro comparison of fracture load of implant-supported, zirconia-based, porcelain- and composite-layered restorations after artificial aging.

    PubMed

    Komine, Futoshi; Taguchi, Kohei; Fushiki, Ryosuke; Kamio, Shingo; Iwasaki, Taro; Matsumura, Hideo

    2014-01-01

    This study evaluated fracture load of single-tooth, implant-supported, zirconia-based, porcelain- and indirect composite-layered restorations after artificial aging. Forty-four zirconia-based molar restorations were fabricated on implant abutments and divided into four groups, namely, zirconia-based all-ceramic restorations (ZAC group) and three types of zirconia-based composite-layered restorations (ZIC-P, ZIC-E, and ZIC groups). Before layering an indirect composite material, the zirconia copings in the ZIC-P and ZIC-E groups were primed with Clearfil Photo Bond and Estenia Opaque Primer, respectively. All restorations were cemented on the abutments with glass-ionomer cement and then subjected to thermal cycling and cyclic loading. All specimens survived thermal cycling and cyclic loading. The fracture load of the ZIC-P group (2.72 kN) was not significantly different from that of the ZAC group (3.05 kN). The fracture load of the zirconia-based composite-layered restoration primed with Clearfil Photo Bond (ZIC-P) was comparable to that of the zirconia-based all-ceramic restoration (ZAC) after artificial aging.

  9. Understanding behavioral effects of early life stress using the reactive scope and allostatic load models

    PubMed Central

    HOWELL, BRITTANY R.; SANCHEZ, MAR M.

    2015-01-01

    The mechanisms through which early life stress leads to psychopathology are thought to involve allostatic load, the “wear and tear” an organism is subjected to as a consequence of sustained elevated levels of glucocorticoids caused by repeated/prolonged stress activations. The allostatic load model described this phenomenon, but has been criticized as inadequate to explain alterations associated with early adverse experience in some systems, including behavior, which cannot be entirely explained from an energy balance perspective. The reactive scope model has been more recently proposed and focuses less on energy balance and more on dynamic ranges of physiological and behavioral mediators. In this review we examine the mechanisms underlying the behavioral consequences of early life stress in the context of both these models. We focus on adverse experiences that involve mother–infant relationship disruption, and dissect those mechanisms involving maternal care as a regulator of development of neural circuits that control emotional and social behaviors in the offspring. We also discuss the evolutionary purpose of the plasticity in behavioral development, which has a clear adaptive value in a changing environment. PMID:22018078

  10. Short-Term and Working Memory Impairments in Early-Implanted, Long-Term Cochlear Implant Users Are Independent of Audibility and Speech Production.

    PubMed

    AuBuchon, Angela M; Pisoni, David B; Kronenberger, William G

    2015-01-01

    To determine whether early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated. Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions that differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing). Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response. Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory using phonological and linguistic strategies during memory tasks.

  11. Short-Term and Working Memory Impairments in Early-Implanted, Long-Term Cochlear Implant Users Are Independent of Audibility and Speech Production

    PubMed Central

    AuBuchon, Angela M.; Pisoni, David B.; Kronenberger, William G.

    2015-01-01

    OBJECTIVES Determine if early-implanted, long-term cochlear implant (CI) users display delays in verbal short-term and working memory capacity when processes related to audibility and speech production are eliminated. DESIGN Twenty-three long-term CI users and 23 normal-hearing controls each completed forward and backward digit span tasks under testing conditions which differed in presentation modality (auditory or visual) and response output (spoken recall or manual pointing). RESULTS Normal-hearing controls reproduced more lists of digits than the CI users, even when the test items were presented visually and the responses were made manually via touchscreen response. CONCLUSIONS Short-term and working memory delays observed in CI users are not due to greater demands from peripheral sensory processes such as audibility or from overt speech-motor planning and response output organization. Instead, CI users are less efficient at encoding and maintaining phonological representations in verbal short-term memory utilizing phonological and linguistic strategies during memory tasks. PMID:26496666

  12. A resonance frequency analysis of sandblasted and acid-etched implants with different diameters: a prospective clinical study during the initial healing period

    PubMed Central

    2017-01-01

    Purpose The possibility of immediate or early loading has become popular in implant dentistry. A prerequisite for the immediate or early loading of an implant prosthesis is the achievement of initial stability in the implant. Moreover, in response to clinicians' interest in verifying clinical stability to determine the optimal time point for functional loading, a non-invasive method to assess implant stability has been developed on the basis of resonance frequency analysis (RFA). The primary objective of this study was to monitor the stability of sandblasted, large-grit, and acid-etched (SLA) implants with different diameters during the early phases of healing by RFA. The secondary objective was to evaluate how the initial stability of implants varied depending on different surface modifications and other contributing factors. Methods Thirty-five implants (25 SLA implants and 10 resorbable blasting media [RBM] implants) placed in 20 subjects were included. To measure implant stability, RFA was performed at baseline and at 1, 2, 3, 4, 6, and 10 weeks after surgery. Results The longitudinal changes in the implant stability quotient (ISQ) values were similar for the SLA implants with different diameters and for the RBM implants. During the initial healing period, the ISQ decreased after installation and reached its lowest values at 1 week and 2 weeks, respectively. The mean ISQ values in the SLA implants were significantly higher in Ø 5.0 mm implants than in Ø 4.0 mm implants. Men showed a higher ISQ than women. Mandibular sites showed a higher ISQ than maxillary sites. Conclusions All implants used in this study are suitable for immediate or early loading under appropriate indications. A wider diameter and SLA surface treatment of implants could improve the stability, if the implant is fixed with at least 30 Ncm of insertion torque. PMID:28462009

  13. Literacy Skills in Children With Cochlear Implants: The Importance of Early Oral Language and Joint Storybook Reading

    PubMed Central

    Ambrose, Sophie E.; Eisenberg, Laurie S.

    2009-01-01

    The goal of this study was to longitudinally examine relationships between early factors (child and mother) that may influence children's phonological awareness and reading skills 3 years later in a group of young children with cochlear implants (N = 16). Mothers and children were videotaped during two storybook interactions, and children's oral language skills were assessed using the “Reynell Developmental Language Scales, third edition.” Three years later, phonological awareness, reading skills, and language skills were assessed using the “Phonological Awareness Test,” the “Woodcock–Johnson-III Diagnostic Reading Battery,” and the “Oral Written Language Scales.” Variables included in the data analyses were child (age, age at implant, and language skills) and mother factors (facilitative language techniques) and children's phonological awareness and reading standard scores. Results indicate that children's early expressive oral language skills and mothers’ use of a higher level facilitative language technique (open-ended question) during storybook reading, although related, each contributed uniquely to children's literacy skills. Individual analyses revealed that the children with expressive standard scores below 70 at Time 1 also performed below average (<85) on phonological awareness and total reading tasks 3 years later. Guidelines for professionals are provided to support literacy skills in young children with cochlear implants. PMID:18417463

  14. Heterogeneous nuclear ribonucleoprotein C1 may control miR-30d levels in endometrial exosomes affecting early embryo implantation.

    PubMed

    Balaguer, N; Moreno, I; Herrero, M; González, M; Simón, C; Vilella, F

    2018-05-29

    Is there a specific mechanism to load the microRNA, hsa-miR-30d, into exosomes to facilitate maternal communication with pre-implantation embryos? The heterogeneous nuclear ribonucleoprotein C1 (hnRNPC1) is involved in the internalization of endometrial miR-30d into exosomes to prepare for its subsequent incorporation into trophectoderm cells. Our group previously described a novel cell-to-cell communication mechanism involving the delivery of endometrial microRNAs (miRNAs) from the maternal endometrium to the trophectoderm cells of preimplantation embryos. Specifically, human endometrial miR-30d is taken up by murine blastocysts causing the overexpression of certain genes involved in embryonic adhesion (Itb3, Itga7 and Cdh5) increasing embryo adhesion rates. Transfer of maternal miR-30d to preimplantation embryos was confirmed by co-culture of Wild-type (WT) and miR-30d knockout (KO) murine embryos with primary cultures of human endometrial epithelial cells (hEECs) in which mir-30d was labelled with specific Molecular Beacon or SmartFlare probes. Potential molecules responsible for the miR-30d loading into exosomes were purified by pull-down analysis with a biotinylated form of miR-30d on protein lysates from human endometrial exosomes, identified using mass spectrometry and assessed by flow cytometry, western blotting and co-localization studies. The role of hnRNPC1 in the miR-30d loading and transportation was interrogated by quantification of this miRNA in exosomes isolated from endometrial cells in which hnRNPC1 was transiently silenced using small interference RNA. Finally, the transfer of miR-30d to WT and KO embryos was assessed upon co-culture with sihnRNPC1 transfected cells. Murine embryos from miR-30d WT and KO mice, (strain MirC26tm1Mtm/Mmjax), were obtained by oviduct flushing of superovulated females. Endometrial Exosomes were purified by ultracentrifugation of supernatants from primary cultures of hEECs or Ishikawa cells. Molecular beacon and

  15. In vivo dendritic cell depletion reduces breeding efficiency, affecting implantation and early placental development in mice.

    PubMed

    Krey, Gesa; Frank, Pierre; Shaikly, Valerie; Barrientos, Gabriela; Cordo-Russo, Rosalia; Ringel, Frauke; Moschansky, Petra; Chernukhin, Igor V; Metodiev, Metodi; Fernández, Nelson; Klapp, Burghard F; Arck, Petra C; Blois, Sandra M

    2008-09-01

    Implantation of mammalian embryos into their mother's uterus ensures optimal nourishment and protection throughout development. Complex molecular interactions characterize the implantation process, and an optimal synchronization of the components of this embryo-maternal dialogue is crucial for a successful reproductive outcome. In the present study, we investigated the role of dendritic cells (DC) during implantation process using a transgenic mouse system (DTRtg) that allows transient depletion of CD11c+ cells in vivo through administration of diphtheria toxin. We observed that DC depletion impairs the implantation process, resulting in a reduced breeding efficiency. Furthermore, the maturity of uterine natural killer cells at dendritic cell knockout (DCKO) implantation sites was affected as well; as demonstrated by decreased perforin expression and reduced numbers of periodic-acid-Schiff (PAS)-positive cells. This was accompanied by disarrangements in decidual vascular development. In the present study, we were also able to identify a novel DC-dependent protein, phosphatidylinositol transfer protein beta (PITPbeta), involved in implantation and trophoblast development using a proteomic approach. Indeed, DCKO mice exhibited substantial anomalies in placental development, including hypocellularity of the spongiotrophoblast and labyrinthine layers and reduced numbers of trophoblast giant cells. Giant cells also down-regulated their expression of two characteristic markers of trophoblast differentiation, placental lactogen 1 and proliferin. In view of these findings, dendritic cells emerge as possible modulators in the orchestration of events leading to the establishment and maintenance of pregnancy.

  16. Bioresorbable β-TCP-FeAg nanocomposites for load bearing bone implants: High pressure processing, properties and cell compatibility.

    PubMed

    Swain, S K; Gotman, I; Unger, R; Gutmanas, E Y

    2017-09-01

    In this paper, the processing and properties of iron-toughened bioresorbable β-tricalcium phosphate (β-TCP) nanocomposites are reported. β-TCP is chemically similar to bone mineral and thus a good candidate material for bioresorbable bone healing devices; however intrinsic brittleness and low bending strength make it unsuitable for use in load-bearing sites. Near fully dense β-TCP-matrix nanocomposites containing 30vol% Fe, with and without addition of silver, were produced employing high energy attrition milling of powders followed by high pressure consolidation/cold sintering at 2.5GPa. In order to increase pure iron's corrosion rate, 10 to 30vol% silver were added to the metal phase. The degradation behavior of the developed composite materials was studied by immersion in Ringer's and saline solutions for up to 1month. The mechanical properties, before and after immersion, were tested in compression and bending. All the compositions exhibited high mechanical strength, the strength in bending being several fold higher than that of polymer toughened β-TCP-30PLA nanocomposites prepared by the similar procedure of attrition milling and cold sintering, and of pure high-temperature sintered β-TCP. Partial substitution of iron with silver led to an increase in both strength and ductility. Furthermore, the galvanic action of silver particles dispersed in the iron phase significantly accelerated in vitro degradation of β-TCP-30(Fe-Ag) nanocomposites. After 1month immersion, the composites retained about 50% of their initial bending strength. In cell culture experiments, β-TCP-27Fe3Ag nanocomposites exhibited no signs of cytotoxicity towards human osteoblasts suggesting that they can be used as an implant material. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. PreImplantation Factor (PIF) correlates with early mammalian embryo development-bovine and murine models

    PubMed Central

    2011-01-01

    Background PreImplantation Factor (PIF), a novel peptide secreted by viable embryos is essential for pregnancy: PIF modulates local immunity, promotes decidual pro-adhesion molecules and enhances trophoblast invasion. To determine the role of PIF in post-fertilization embryo development, we measured the peptide's concentration in the culture medium and tested endogenous PIF's potential trophic effects and direct interaction with the embryo. Methods Determine PIF levels in culture medium of multiple mouse and single bovine embryos cultured up to the blastocyst stage using PIF-ELISA. Examine the inhibitory effects of anti-PIF-monoclonal antibody (mAb) added to medium on cultured mouse embryos development. Test FITC-PIF uptake by cultured bovine blastocysts using fluorescent microscopy. Results PIF levels in mouse embryo culture medium significantly increased from the morula to the blastocyst stage (ANOVA, P = 0.01). In contrast, atretic embryos medium was similar to the medium only control. Detectable - though low - PIF levels were secreted already by 2-cell stage mouse embryos. In single bovine IVF-derived embryos, PIF levels in medium at day 3 of culture were higher than non-cleaving embryos (control) (P = 0.01) and at day 7 were higher than day 3 (P = 0.03). In non-cleaving embryos culture medium was similar to medium alone (control). Anti-PIF-mAb added to mouse embryo cultures lowered blastocyst formation rate 3-fold in a dose-dependent manner (2-way contingency table, multiple groups, X2; P = 0.01) as compared with non-specific mouse mAb, and medium alone, control. FITC-PIF was taken-up by cultured bovine blastocysts, but not by scrambled FITC-PIF (control). Conclusions PIF is an early embryo viability marker that has a direct supportive role on embryo development in culture. PIF-ELISA use to assess IVF embryo quality prior to transfer is warranted. Overall, our data supports PIF's endogenous self sustaining role in embryo development and the utility of PIF

  18. Early Osteoarthritis of the Trapeziometacarpal Joint Is Not Associated With Joint Instability during Typical Isometric Loading

    PubMed Central

    Halilaj, Eni; Moore, Douglas C.; Patel, Tarpit K.; Ladd, Amy L.; Weiss, Arnold-Peter C.; Crisco, Joseph J.

    2015-01-01

    The saddle-shaped trapeziometacarpal (TMC) joint contributes importantly to the function of the human thumb. A balance between mobility and stability is essential in this joint, which experiences high loads and is prone to osteoarthritis (OA). Since instability is considered a risk factor for TMC OA, we assessed TMC joint instability during the execution of three isometric functional tasks (key pinch, jar grasp, and jar twist) in 76 patients with early TMC OA and 44 asymptomatic controls. Computed tomography images were acquired while subjects held their hands relaxed and while they applied 80% of their maximum effort for each task. Six degree-of-freedom rigid body kinematics of the metacarpal with respect to the trapezium from the unloaded to the loaded task positions were computed in terms of a TMC joint coordinate system. Joint instability was expressed as a function of the metacarpal translation and the applied force. We found that the TMC joint was more unstable during a key pinch task than during a jar grasp or a jar twist task. Sex, age, and early OA did not have an effect on TMC joint instability, suggesting that instability during these three tasks is not a predisposing factor in TMC OA. PMID:25941135

  19. Interdependence of Linguistic and Indexical Speech Perception Skills in School-Aged Children with Early Cochlear Implantation

    PubMed Central

    Geers, Ann; Davidson, Lisa; Uchanski, Rosalie; Nicholas, Johanna

    2013-01-01

    Objectives This study documented the ability of experienced pediatric cochlear implant (CI) users to perceive linguistic properties (what is said) and indexical attributes (emotional intent and talker identity) of speech, and examined the extent to which linguistic (LSP) and indexical (ISP) perception skills are related. Pre-implant aided hearing, age at implantation, speech processor technology, CI-aided thresholds, sequential bilateral cochlear implantation, and academic integration with hearing age-mates were examined for their possible relationships to both LSP and ISP skills. Design Sixty 9–12 year olds, first implanted at an early age (12–38 months), participated in a comprehensive test battery that included the following LSP skills: 1) recognition of monosyllabic words at loud and soft levels, 2) repetition of phonemes and suprasegmental features from non-words, and 3) recognition of keywords from sentences presented within a noise background, and the following ISP skills: 1) discrimination of male from female and female from female talkers and 2) identification and discrimination of emotional content from spoken sentences. A group of 30 age-matched children without hearing loss completed the non-word repetition, and talker- and emotion-perception tasks for comparison. Results Word recognition scores decreased with signal level from a mean of 77% correct at 70 dB SPL to 52% at 50 dB SPL. On average, CI users recognized 50% of keywords presented in sentences that were 9.8 dB above background noise. Phonetic properties were repeated from non-word stimuli at about the same level of accuracy as suprasegmental attributes (70% and 75%, respectively). The majority of CI users identified emotional content and differentiated talkers significantly above chance levels. Scores on LSP and ISP measures were combined into separate principal component scores and these components were highly correlated (r = .76). Both LSP and ISP component scores were higher for children

  20. Visual short-term memory load modulates the early attention and perception of task-irrelevant emotional faces

    PubMed Central

    Yang, Ping; Wang, Min; Jin, Zhenlan; Li, Ling

    2015-01-01

    The ability to focus on task-relevant information, while suppressing distraction, is critical for human cognition and behavior. Using a delayed-match-to-sample (DMS) task, we investigated the effects of emotional face distractors (positive, negative, and neutral faces) on early and late phases of visual short-term memory (VSTM) maintenance intervals, using low and high VSTM loads. Behavioral results showed decreased accuracy and delayed reaction times (RTs) for high vs. low VSTM load. Event-related potentials (ERPs) showed enhanced frontal N1 and occipital P1 amplitudes for negative faces vs. neutral or positive faces, implying rapid attentional alerting effects and early perceptual processing of negative distractors. However, high VSTM load appeared to inhibit face processing in general, showing decreased N1 amplitudes and delayed P1 latencies. An inverse correlation between the N1 activation difference (high-load minus low-load) and RT costs (high-load minus low-load) was found at left frontal areas when viewing negative distractors, suggesting that the greater the inhibition the lower the RT cost for negative faces. Emotional interference effect was not found in the late VSTM-related parietal P300, frontal positive slow wave (PSW) and occipital negative slow wave (NSW) components. In general, our findings suggest that the VSTM load modulates the early attention and perception of emotional distractors. PMID:26388763

  1. Sagittal and vertical load-deflection and permanent deformation of transpalatal arches connected with palatal implants: an in-vitro study.

    PubMed

    Crismani, Adriano G; Celar, Ales G; Burstone, Charles J; Bernhart, Thomas G; Bantleon, Hans-Peter; Mittlboeck, Martina

    2007-06-01

    The purposes of this laboratory investigation were to (1) measure the sagittal and vertical deflection of loaded transpalatal arches (TPAs) connected to a palatal implant, (2) measure the extent of permanent deformation of the connecting TPA in the sagittal and vertical directions, (3) test various wire dimensions in terms of deflection behavior, and (4) evaluate soldering vs laser welding vs adhesive bonding of TPAs in terms of load deflection behavior. Stainless steel wires of 6 dimensions were tested: 0.8 x 0.8, 0.9, 1, 1.1, 1.2, and 1.2 x 1.2 mm. For each dimension, 10 specimens were soldered to the palatal implant abutment, 10 were laser welded, and 10 were adhesively bonded to the implant abutment (total, 180 specimens). The measuring device applied increments of force of 50 cN, from 0 to 500 cN. Then the specimens were unloaded. The values were statistically described and analyzed with ANOVA and Wilcoxon rank sum tests. Absolute orthodontic anchorage without deformation of TPAs was not observed with the wire dimensions tested. To prevent loss of anchorage greater than 370 mum (sagittal deflection of 1.2 x 1.2 mm adhesively bonded TPA at 500 cN force level), wires thicker than 1.2 x 1.2 mm or cast anchorage elements must be considered for clinical practice. However, larger cross sections might cause more patient discomfort, and laboratory procedures increase costs.

  2. The effect of load on heat production, thermal effects and expenditure of time during implant site preparation - an experimental ex vivo comparison between piezosurgery and conventional drilling.

    PubMed

    Stelzle, Florian; Frenkel, Carsten; Riemann, Max; Knipfer, Christian; Stockmann, Philipp; Nkenke, Emeka

    2014-02-01

    Piezoelectric surgery (PS) is meant to be a gentle osteotomy method. The aim of this study was to compare piezosurgical vs. conventional drilling methods for implant site preparation (ISP) - focusing on load-dependent thermal effect on hard tissue and the expenditure of ISP time. Three hundred and sixty ISP were performed on ex vivo pig heads using piezosurgery, spiral burs (SB) and trephine burs (TB). The load applied was increased from 0 to 1000 g in 100-g intervals. Temperature within the bone was measured with a thermocouple, and duration was recorded with a stop watch. Thermal effects were histomorphometrically analysed. Twelve ISPs per technique were performed at the lateral wall of the maxillary sinus. PS yields the highest mean temperatures (48.6 ± 3.4°C) and thermal effects (200.7 ± 44.4 μm), both at 900-1000 g. Duration is reduced with a plus of load and significantly longer in either case for PS (P < 0.05). There is a correlation of the applied load with all other examined factors for PS and TB. Temperature and histological effects decrease for SB beyond 500 g. PS yields significantly higher temperatures and thermal tissue alterations on load levels higher than 500 g and is significantly slower for ISP compared to SB and TB. For ISP with PS, a maximum load of 400 g should be maintained. © 2012 John Wiley & Sons A/S.

  3. Risk factors for implant failure: a retrospective study in an educational institution using GEE analyses.

    PubMed

    Borba, Marcelo; Deluiz, Daniel; Lourenço, Eduardo José Veras; Oliveira, Luciano; Tannure, Patrícia Nivoloni

    2017-08-21

    This study aimed to evaluate dental implant outcomes and to identify risk factors associated with implant failure over 12 years via dental records of patients attending an educational institution. Dental records of 202 patients receiving 774 dental implants from 2002 to 2014 were analyzed by adopting a more reliable statistical method to evaluate risk factors with patients as the unit [generalized estimating equation (GEE)]. Information regarding patient age at implantation, sex, use of tobacco, and history of systemic diseases was collected. Information about implant location in the arch region and implant length, diameter, and placement in a grafted area was evaluated after 2 years under load. Systemic and local risk factors for early and late implant failure were studied. A total of 18 patients experienced 25 implant failures, resulting in an overall survival rate of 96.8% (2.84% and 0.38% early and late implant failures, respectively). The patient-based survival rate was 91.8%. GEE univariate and multivariate analyses revealed that a significant risk factor for implant failure was the maxillary implant (p = 0.006 and p = 0.014, respectively). Bone grafting appeared to be a risk factor for implant failure (p = 0.054). According to GEE analyses, maxillary implants had significantly worse outcomes in this population and were considered to be a risk factor for implant failure. Our results suggested that implants placed in a bone augmentation area had a tendency to fail.

  4. Word Learning in Deaf Children with Cochlear Implants: Effects of Early Auditory Experience

    ERIC Educational Resources Information Center

    Houston, Derek M.; Stewart, Jessica; Moberly, Aaron; Hollich, George; Miyamoto, Richard T.

    2012-01-01

    Word-learning skills were tested in normal-hearing 12- to 40-month-olds and in deaf 22- to 40-month-olds 12 to 18 months after cochlear implantation. Using the Intermodal Preferential Looking Paradigm (IPLP), children were tested for their ability to learn two novel-word/novel-object pairings. Normal-hearing children demonstrated learning on this…

  5. Expressive Vocabulary, Morphology, Syntax and Narrative Skills in Profoundly Deaf Children after Early Cochlear Implantation

    ERIC Educational Resources Information Center

    Boons, Tinne; De Raeve, Leo; Langereis, Margreet; Peeraer, Louis; Wouters, Jan; van Wieringen, Astrid

    2013-01-01

    Practical experience and research reveal generic spoken language benefits after cochlear implantation. However, systematic research on specific language domains and error analyses are required to probe sub-skills. Moreover, the effect of predictive factors on distinct language domains is unknown. In this study, outcomes of 70 school-aged children…

  6. Expression of caveolin-1 in the early phase of beta-TCP implanted in dog mandible.

    PubMed

    Chou, Cherng-Tzeh; Bhawal, Ujjal K; Watanabe, Nobuyuki; Kuboyama, Noboru; Chang, Wei-Jen; Lee, Sheng-Yang; Abiko, Yoshimitsu

    2013-07-01

    Caveolin is an essential and signature protein of caveolae. Caveolin-1 participates in signal transduction processes by acting as a scaffolding protein that concentrates, organizes and functional regulates signalling molecules within caveolar membranes. Beta-tricalcium phosphate (β-TCP) has been widely used for scaffold in tissue engineering due to its high biodegradability, osteoconductivity, easy manipulation, and lack of histotoxicity. To better understand the role of caveolin-1 in bone homeostasis and response to β-TCP scaffold, β-TCP was implanted into the dog mandible defects in beagle dogs, and gene expression profiles were examined focused on the molecular components involved in caveolin-1 regulation. Here we showed the quantitative imageology analysis characterized using in vivo micro-computed tomography (CT) images at 4 and 7 days after β-TCP implanted in dog mandibles. The bone reformation by using the β-TCP scaffolds began within 4 days of surgery, and was healing well at 7 days after surgery. Higher mRNA level of caveolin-1 was observed in β-TCP-implanted Beagle dog mandibles compared with controls at day 4 and day 7 post-surgery. The enhancement of caveolin-1 by β-TCP was further confirmed by immunohistochemistry and immunofluorescence analysis. We further revealed increased Smad7 and Phospho Stat3 expression in β-TCP-implanted specimens. Taken together, these results suggest that the enhancement of caveolin-1 play an important role in accelerating bone formation by β-TCP. Copyright © 2013 Wiley Periodicals, Inc.

  7. Interdependence of linguistic and indexical speech perception skills in school-age children with early cochlear implantation.

    PubMed

    Geers, Ann E; Davidson, Lisa S; Uchanski, Rosalie M; Nicholas, Johanna G

    2013-09-01

    This study documented the ability of experienced pediatric cochlear implant (CI) users to perceive linguistic properties (what is said) and indexical attributes (emotional intent and talker identity) of speech, and examined the extent to which linguistic (LSP) and indexical (ISP) perception skills are related. Preimplant-aided hearing, age at implantation, speech processor technology, CI-aided thresholds, sequential bilateral cochlear implantation, and academic integration with hearing age-mates were examined for their possible relationships to both LSP and ISP skills. Sixty 9- to 12-year olds, first implanted at an early age (12 to 38 months), participated in a comprehensive test battery that included the following LSP skills: (1) recognition of monosyllabic words at loud and soft levels, (2) repetition of phonemes and suprasegmental features from nonwords, and (3) recognition of key words from sentences presented within a noise background, and the following ISP skills: (1) discrimination of across-gender and within-gender (female) talkers and (2) identification and discrimination of emotional content from spoken sentences. A group of 30 age-matched children without hearing loss completed the nonword repetition, and talker- and emotion-perception tasks for comparison. Word-recognition scores decreased with signal level from a mean of 77% correct at 70 dB SPL to 52% at 50 dB SPL. On average, CI users recognized 50% of key words presented in sentences that were 9.8 dB above background noise. Phonetic properties were repeated from nonword stimuli at about the same level of accuracy as suprasegmental attributes (70 and 75%, respectively). The majority of CI users identified emotional content and differentiated talkers significantly above chance levels. Scores on LSP and ISP measures were combined into separate principal component scores and these components were highly correlated (r = 0.76). Both LSP and ISP component scores were higher for children who received a CI

  8. Effect of framework material and vertical misfit on stress distribution in implant-supported partial prosthesis under load application: 3-D finite element analysis.

    PubMed

    Bacchi, Ataís; Consani, Rafael Leonardo Xediek; Mesquita, Marcelo Ferraz; Dos Santos, Mateus Bertolini Fernandes

    2013-09-01

    This study evaluated the influence of framework material and vertical misfit on stress created in an implant-supported partial prosthesis under load application. The posterior part of a severely reabsorbed jaw with a fixed partial prosthesis above two osseointegrated titanium implants at the place of the second premolar and second molar was modeled using SolidWorks 2010 software. Finite element models were obtained by importing the solid model into an ANSYS Workbench 11 simulation. The models were divided into 15 groups according to their prosthetic framework material (type IV gold alloy, silver-palladium alloy, commercially pure titanium, cobalt-chromium alloy or zirconia) and vertical misfit level (10 µm, 50 µm and 100 µm). After settlement of the prosthesis with the closure of the misfit, simultaneous loads of 110 N vertical and 15 N horizontal were applied on the occlusal and lingual faces of each tooth, respectively. The data was evaluated using Maximum Principal Stress (framework, porcelain veneer and bone tissue) and a von Mises Stress (retention screw) provided by the software. As a result, stiffer frameworks presented higher stress concentrations; however, these frameworks led to lower stresses in the porcelain veneer, the retention screw (faced to 10 µm and 50 µm of the misfit) and the peri-implant bone tissues. The increase in the vertical misfit resulted in stress values increasing in all of the prosthetic structures and peri-implant bone tissues. The framework material and vertical misfit level presented a relevant influence on the stresses for all of the structures evaluated.

  9. Long-Term Retrospective Clinical and Radiographic Follow-up of 205 Brånemark System Mk III TiUnite Implants Submitted to Either Immediate or Delayed Loading.

    PubMed

    Imburgia, Mario; Del Fabbro, Massimo

    2015-10-01

    Studies are needed to evaluate long-term performance of immediately loaded implants with moderately rough surface. This retrospective study evaluated long-term survival and periimplant soft and hard tissue conditions in patients treated with TiUnite implants. Forty-one consecutive patients (mean age, 52.6 years) received 205 Brånemark System Mk III TiUnite implants (145 maxillary, 60 mandibular). The indication was single tooth (n = 7 implants), partial (n = 94), or full arches (n = 104). One hundred thirteen implants were immediately loaded. Cumulative survival rate (CSR) of implants was assessed. Long-term marginal bone remodeling, probing pocket depth (PPD), and periimplant mucosa conditions were assessed. Follow-up averaged 8.8 years (range, 6.6-10.6 years). Eight implants in 5 patients failed. CSR was 96.1% (implant basis) and 87.8% (patient basis) up to 10 years. At the longest follow-up, bone loss averaged 0.43 ± 1.15 mm (n = 173), PPD averaged 3.64 ± 0.74 mm, and periimplant mucosa was healthy in 74.6% of cases. Furthermore, 50.3% and 35.5% of implants scored negative for plaque and bleeding, respectively. No significant difference in CSR and hard and soft tissue conditions was found in the long term between immediately and delayed loaded implants. Implants with TiUnite surface demonstrated excellent long-term survival, marginal bone response, and soft tissue conditions, despite a nonoptimal level of oral hygiene.

  10. Socket grafting with or without buccal augmentation with anorganic bovine bone at immediate post-extractive implants: 6-month after loading results from a multicenter randomised controlled clinical trial.

    PubMed

    Zuffetti, Francesco; Esposito, Marco; Capelli, Matteo; Galli, Fabio; Testori, Tiziano; Del Fabbro, Massimo

    2013-01-01

    To evaluate whether grafting with additional anorganic bovine bone to augment horizontally the buccal plate (internal and external grafting [IEG]) at single post-extractive implants preserves the alveolar ridge, improving aesthetics, better than internal socket grafting alone (ISGA). A total of 78 patients, treated in four Italian private practices, requiring a single immediate post-extractive implant, having at least 1 mm of implant-to-buccal bone gap after implant insertion and a preserved buccal bone, had the residual bone-to-implant gap filled with anorganic bovine bone. Thirty-nine randomly allocated patients received additional buccal horizontal augmentation of about 2 mm thickness with the same bone substitute (IEG group) covered with collagen resorbable membranes. Implants were submerged for 4 months before being loaded with provisional acrylic crowns. Definitive crowns were delivered after 6 months. Outcome measures were crown/implant failures, complications and aesthetics recorded by blinded assessors 6 months after initial loading, at delivery of definitive crowns. Six months after initial loading, 8 patients dropped out, did not complete the treatment or were treated twice and therefore had to be excluded (4 from each group). There were no statistically significant differences for implant failures and complications between the two groups. Two implants failed in the IEG group versus 1 in the ISGA group. Four complications occurred, 2 in each group. The mean implant aesthetic score (IAS) was 7.8 at ISGA sites and 8.0 at IEG sites. There were no statistically significant differences between the two groups (P = 0.492; difference 0.2 mm; 95% CI -0.769, 0.369) for IAS score. There were no statistically significant differences in the outcomes between the centres. The use of adjunctive anorganic bovine bone placed buccally at preserved buccal sites of immediate post-extractive implants may not improve the aesthetic outcome, however additional research is needed

  11. The perception of prosody and associated auditory cues in early-implanted children: the role of auditory working memory and musical activities.

    PubMed

    Torppa, Ritva; Faulkner, Andrew; Huotilainen, Minna; Järvikivi, Juhani; Lipsanen, Jari; Laasonen, Marja; Vainio, Martti

    2014-03-01

    To study prosodic perception in early-implanted children in relation to auditory discrimination, auditory working memory, and exposure to music. Word and sentence stress perception, discrimination of fundamental frequency (F0), intensity and duration, and forward digit span were measured twice over approximately 16 months. Musical activities were assessed by questionnaire. Twenty-one early-implanted and age-matched normal-hearing (NH) children (4-13 years). Children with cochlear implants (CIs) exposed to music performed better than others in stress perception and F0 discrimination. Only this subgroup of implanted children improved with age in word stress perception, intensity discrimination, and improved over time in digit span. Prosodic perception, F0 discrimination and forward digit span in implanted children exposed to music was equivalent to the NH group, but other implanted children performed more poorly. For children with CIs, word stress perception was linked to digit span and intensity discrimination: sentence stress perception was additionally linked to F0 discrimination. Prosodic perception in children with CIs is linked to auditory working memory and aspects of auditory discrimination. Engagement in music was linked to better performance across a range of measures, suggesting that music is a valuable tool in the rehabilitation of implanted children.

  12. Early life vitamin D depletion alters the postnatal response to skeletal loading in growing and mature bone

    PubMed Central

    Buckley, Harriet; Owen, Robert; Marin, Ana Campos; Lu, Yongtau; Eyles, Darryl; Lacroix, Damien; Reilly, Gwendolen C.; Skerry, Tim M.; Bishop, Nick J.

    2018-01-01

    There is increasing evidence of persistent effects of early life vitamin D exposure on later skeletal health; linking low levels in early life to smaller bone size in childhood as well as increased fracture risk later in adulthood, independently of later vitamin D status. A major determinant of bone mass acquisition across all ages is mechanical loading. We tested the hypothesis in an animal model system that early life vitamin D depletion results in abrogation of the response to mechanical loading, with consequent reduction in bone size, mass and strength during both childhood and adulthood. A murine model was created in which pregnant dams were either vitamin D deficient or replete, and their offspring moved to a vitamin D replete diet at weaning. Tibias of the offspring were mechanically loaded and bone structure, extrinsic strength and growth measured both during growth and after skeletal maturity. Offspring of vitamin D deplete mice demonstrated lower bone mass in the non loaded limb and reduced bone mass accrual in response to loading in both the growing skeleton and after skeletal maturity. Early life vitamin D depletion led to reduced bone strength and altered bone biomechanical properties. These findings suggest early life vitamin D status may, in part, determine the propensity to osteoporosis and fracture that blights later life in many individuals. PMID:29370213

  13. Prospective Single-Arm, Multi-Center Trial of a Patient-Specific Interpositional Knee Implant: Early Clinical Results

    PubMed Central

    Koeck, F.X; Luring, C; Goetz, J; Handel, M; Tingart, M; Grifka, J; Beckmann, J

    2011-01-01

    Background: The treatment of unicompartmental arthritis in younger patients is challenging. The aim of this study is to report final safety and efficacy analysis results for the iForma patient–specific interpositional device, which is designed for the treatment of isolated medial or lateral compartment arthritis of the knee. Methods: From June 2005 to June 2008 78 subjects (42 men, 36 women) received an iForma implant. The mean age was 53 years, the mean Body Mass Index 29.0. We surveyed the WOMAC scores, the visual analog pain scale and the Knee Society Scores. Results: The mean follow up was 16.4 months. The mean WOMAC knee scores increased from 48.3 before surgery to 71.3 after 24 months. A reduction in pain was achieved for all five pain measures using a standard visual analog scale (VAS). Knee Society Knee Score improved from 39.2 before to 61.9 24 month after surgery. The Knee Society Function Scores improved form preoperative 64.5 to 82.5 2 years postoperative. The preoperative range of motion could be restored. The overall revision rate was 24%. 15 implants were removed early, 4 knees were revised without implant removal. Conclusion: Within narrow indication of patients with unicompartmental disease, the iForma device can provide improvement in knee function and reduction in pain, however, with a significant higher risk of early revision compared to traditional arthroplasty. Respecting this limitation it may be an alternative option for arthritic patients with unicompartmental disease who have contraindications to High Tibial Osteotomy or are too young for knee replacement; the iForma device further has the distinct advantage of time and cost saving compared to those procedures. PMID:21552462

  14. Allostasis and Allostatic Load in the Context of Poverty in Early Childhood

    PubMed Central

    Blair, Clancy; Raver, Cybele; Granger, Douglas; Mills-Koonce, Roger; Hibel, Leah

    2014-01-01

    This paper examined the relation of early environmental adversity associated with poverty to child resting or basal level of cortisol in a prospective longitudinal sample of 1,135 children seen at 7, 15, 24, 35, and 48 months of age. We found main effects for length of time in poverty, poor housing quality, African American ethnicity, and low positive caregiving behavior in which each was uniquely associated with an overall higher level of cortisol from age 7 months to 48 months. We also found that two aspects of the early environment in the context of poverty, adult exits from the home and perceived economic insufficiency, were related to salivary cortisol in a time dependent manner. The effect for the first of these, exits from the home, was consistent with the principle of allostatic load in which the effects of adversity on stress physiology accumulate over time. The effect for perceived economic insufficiency was one in which insufficiency was associated with higher levels of cortisol in infancy but with a typical but steeper decline in cortisol with age at subsequent time points. PMID:21756436

  15. Shall we stay, or shall we switch? Continued anti-VEGF therapy versus early switch to dexamethasone implant in refractory diabetic macular edema.

    PubMed

    Busch, Catharina; Zur, Dinah; Fraser-Bell, Samantha; Laíns, Inês; Santos, Ana Rita; Lupidi, Marco; Cagini, Carlo; Gabrielle, Pierre-Henry; Couturier, Aude; Mané-Tauty, Valérie; Giancipoli, Ermete; Ricci, Giuseppe D'Amico; Cebeci, Zafer; Rodríguez-Valdés, Patricio J; Chaikitmongkol, Voraporn; Amphornphruet, Atchara; Hindi, Isaac; Agrawal, Kushal; Chhablani, Jay; Loewenstein, Anat; Iglicki, Matias; Rehak, Matus

    2018-05-05

    To compare functional and anatomical outcomes of continued anti-vascular endothelial growth factor (VEGF) therapy versus dexamethasone (DEX) implant in eyes with refractory diabetic macular edema (DME) after three initial anti-VEGF injections in a real-world setting. To be included in this retrospective multicenter, case-control study, eyes were required: (1) to present with early refractory DME, as defined by visual acuity (VA) gain ≤ 5 letters or reduction in central subfield thickness (CST) ≤ 20%, after a loading phase of anti-VEGF therapy (three monthly injections) and (2) to treat further with (a) anti-VEGF therapy or (b) DEX implant. Main outcome measures were change in visual acuity (VA) and central subfield thickness (CST) at 12 months. Due to imbalanced baseline characteristics, a matched anti-VEGF group was formed by only keeping eyes with similar baseline characteristics as those in the DEX group. A total of 110 eyes from 105 patients were included (anti-VEGF group: 72 eyes, DEX group: 38 eyes). Mean change in VA at 12 months was - 0.4 ± 10.8 letters (anti-VEGF group), and + 6.1 ± 10.6 letters (DEX group) (P = 0.004). Over the same period, mean change in CST was + 18.3 ± 145.9 µm (anti-VEGF group) and - 92.8 ± 173.6 µm (DEX group) (P < 0.001). Eyes in the DEX group were more likely to gain ≥ 10 letters (OR 3.71, 95% CI 1.19-11.61, P = 0.024) at month 12. In a real-world setting, eyes with DME considered refractory to anti-VEGF therapy after three monthly injections which were switched to DEX implant and had better visual and anatomical outcomes at 12 months than those that continued treatment with anti-VEGF therapy.

  16. Measuring the load-bearing ratio between mucosa and abutments beneath implant- and tooth-supported overdentures: an in vivo preliminary study.

    PubMed

    Ando, Takanori; Maeda, Yoshinobu; Wada, Masahiro; Gonda, Tomoya

    2011-01-01

    The aim of this study was to establish a method for in vivo examination of the load-bearing ratio between mucosa and abutments beneath an overdenture. Two patients wearing a four tooth-supported or a four implant-supported overdenture were enrolled in this study. Recordings were performed with the metal framework only or with a metal framework and a denture base. The force value with the framework only was designated as 100%, and the tissue-supporting ratio (TSR) with the denture base was calculated. The TSR was approximately 30% to 40% in both subjects, regardless of the load. These data suggest that measurement of a TSR beneath an overdenture is feasible.

  17. Mechanical characterization of structurally porous biomaterials built via additive manufacturing: experiments, predictive models, and design maps for load-bearing bone replacement implants.

    PubMed

    Melancon, D; Bagheri, Z S; Johnston, R B; Liu, L; Tanzer, M; Pasini, D

    2017-11-01

    Porous biomaterials can be additively manufactured with micro-architecture tailored to satisfy the stringent mechano-biological requirements imposed by bone replacement implants. In a previous investigation, we introduced structurally porous biomaterials, featuring strength five times stronger than commercially available porous materials, and confirmed their bone ingrowth capability in an in vivo canine model. While encouraging, the manufactured biomaterials showed geometric mismatches between their internal porous architecture and that of its as-designed counterpart, as well as discrepancies between predicted and tested mechanical properties, issues not fully elucidated. In this work, we propose a systematic approach integrating computed tomography, mechanical testing, and statistical analysis of geometric imperfections to generate statistical based numerical models of high-strength additively manufactured porous biomaterials. The method is used to develop morphology and mechanical maps that illustrate the role played by pore size, porosity, strut thickness, and topology on the relations governing their elastic modulus and compressive yield strength. Overall, there are mismatches between the mechanical properties of ideal-geometry models and as-manufactured porous biomaterials with average errors of 49% and 41% respectively for compressive elastic modulus and yield strength. The proposed methodology gives more accurate predictions for the compressive stiffness and the compressive strength properties with a reduction of the average error to 11% and 7.6%. The implications of the results and the methodology here introduced are discussed in the relevant biomechanical and clinical context, with insight that highlights promises and limitations of additively manufactured porous biomaterials for load-bearing bone replacement implants. In this work, we perform mechanical characterization of load-bearing porous biomaterials for bone replacement over their entire design

  18. The effects of early auditory-based intervention on adult bilateral cochlear implant outcomes.

    PubMed

    Lim, Stacey R

    2017-09-01

    The goal of this exploratory study was to determine the types of improvement that sequentially implanted auditory-verbal and auditory-oral adults with prelingual and childhood hearing loss received in bilateral listening conditions, compared to their best unilateral listening condition. Five auditory-verbal adults and five auditory-oral adults were recruited for this study. Participants were seated in the center of a 6-loudspeaker array. BKB-SIN sentences were presented from 0° azimuth, while multi-talker babble was presented from various loudspeakers. BKB-SIN scores in bilateral and the best unilateral listening conditions were compared to determine the amount of improvement gained. As a group, the participants had improved speech understanding scores in the bilateral listening condition. Although not statistically significant, the auditory-verbal group tended to have greater speech understanding with greater levels of competing background noise, compared to the auditory-oral participants. Bilateral cochlear implantation provides individuals with prelingual and childhood hearing loss with improved speech understanding in noise. A higher emphasis on auditory development during the critical language development years may add to increased speech understanding in adulthood. However, other demographic factors such as age or device characteristics must also be considered. Although both auditory-verbal and auditory-oral approaches emphasize spoken language development, they emphasize auditory development to different degrees. This may affect cochlear implant (CI) outcomes. Further consideration should be made in future auditory research to determine whether these differences contribute to performance outcomes. Additional investigation with a larger participant pool, controlled for effects of age and CI devices and processing strategies, would be necessary to determine whether language learning approaches are associated with different levels of speech understanding

  19. Sources of Variability in Language Development of Children with Cochlear Implants: Age at Implantation, Parental Language, and Early Features of Children's Language Construction

    ERIC Educational Resources Information Center

    Szagun, Gisela; Schramm, Satyam A.

    2016-01-01

    The aim of the present study was to analyze the relative influence of age at implantation, parental expansions, and child language internal factors on grammatical progress in children with cochlear implants (CI). Data analyses used two longitudinal corpora of spontaneous speech samples, one with twenty-two and one with twenty-six children,…

  20. Outflow resistance of the Baerveldt glaucoma drainage implant and modifications for early postoperative intraocular pressure control.

    PubMed

    Breckenridge, R Reid; Bartholomew, Luanna R; Crosson, Craig E; Kent, Alexander R

    2004-10-01

    To determine outflow resistance of the Baerveldt glaucoma implant using different tube configurations. Outflow resistance of 6 tube configurations (C1- C6) of Baerveldt implants was measured under conditions of constant pressure perfusion. Pressures ranged from 2 to 55 mm Hg. Venting slits were created using a 7-0 Vicryl, spatulated suture-needle. Seton tubes were occluded by threading a retrograde suture approximately 1.5 cm into the lumen. At pressures between 2 and 55 mm Hg, mean outflow resistance of the normally configured seton (ie, open tube; C1) was 0.41 (+/- 0.6) mm Hg/microL/min. Resistance was unchanged (mean 0.41 (+/- 0.4) mm Hg/microL/min) by the addition of 4 venting slits (C2) to the seton tube. Occlusion of the open seton tube with a 3-0 Supramid suture (C3) significantly increased (P < 0.001) mean outflow resistance to 14.99 (+/- 0.6) mm Hg/microL/min. Occlusion of the tube with a 4-0 Supramid suture (C4) significantly increased (P < 0.001) mean outflow resistance to 1.09 (+/- 0.5) mm Hg/microL/min. In implants where tubes were occluded with a 3-0 Supramid suture, the addition of venting slits (C5) significantly decreased (P = 0.038) mean outflow resistance to 8.98 (+/- 0.4) mm Hg/microL/min. In tubes occluded with a 4-0 Supramid suture, the addition of venting slits (C6) decreased mean outflow resistance to 0.98 (+/- 0.6) mm Hg/microL/min. Although these results cannot be directly correlated to the clinical setting, they do show that outflow resistance can be modified at the time of surgery by changing tube configuration of the Baerveldt glaucoma implant. Configuration C5 (3-0 Supramid with venting slits) closely approximates the outflow rate in the normal intraocular pressure range.

  1. The immunologic and antioxidant effects of L-phenylalanine on the uterine implantation of mice embryos during early pregnancy.

    PubMed

    Dong, Yulan; Bai, Yongping; Liu, Guanhui; Wang, Zixu; Cao, Jing; Chen, Yaoxing; Yang, Hongliang

    2014-10-01

    L-phenylalanine (L-PHE) is a synthetic precursor of catecholamines. Because it cannot be synthesised by an organism, it must be absorbed from the environment. Despite the wide use of L-PHE, whether L-PHE has a negative impact on embryo implantation and development is poorly understood. This study attempted to determine the roles of L-PHE in embryo implantation and development and in the immune response and antioxidant status of the uterus in early pregnancy mice injected intraperitoneally with 320 mg/kg L-PHE. The embryo number of treated mice decreased by 57.6%, and the size of their embryos was reduced by 2.8% (P⟩0.05) along the long diameter and 11.9% (P⟨0.05) along the short diameter at E9 compared with control mice. In addition, L-PHE significantly suppressed B lymphocyte proliferation. L-PHE increased IL-2 secretion but decreased the IL-4 concentration, thereby up-regulating the ratio of IL-2/IL-4 to 1.37-8.45. An analysis of the oxidant and antioxidant status showed that, compared with the control mice, the level of superoxide dismutase activity decreased by 21.54-39.94% and the glutathione peroxidase activity decreased by 15.27-18.96% among the L-PHE-treated mice at E1-E9. However, the malonaldehyde content increased by 14.29%-90.11% among the L-PHE-treated mice. Therefore, L-PHE impaired embryo implantation by disrupting cytokine-based immunity and oxidative stress in the uterus.

  2. Early implant placement for a patient with ectodermal dysplasia: Thirteen years of clinical care.

    PubMed

    Knobloch, Lisa A; Larsen, Peter E; Saponaro, Paola C; L'Homme-Langlois, Emilie

    2017-11-29

    Patients with ectodermal dysplasia have abnormalities of 2 or more structures that originate from the ectoderm. The oral manifestations often include the congenital absence of teeth and malformed teeth. This clinical report describes the interdisciplinary care from childhood through the definitive dental rehabilitation completed at skeletal maturation to replace the missing teeth in a patient with ectodermal dysplasia. Treatment began at 9 years of age with an implant-assisted mandibular overdenture to improve function and replace the missing mandibular teeth. Orthodontic treatment for the consolidation of space, composite resin restorations, and interim removable dental prostheses were provided to improve esthetics and replace the missing maxillary teeth. Skeletal growth was monitored, and orthognathic surgery was performed at the cessation of growth. The definitive rehabilitation consisted of a mandibular fixed dental prosthesis supported by dental implants and a maxillary removable dental prosthesis to restore the patient to esthetics and function. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  3. A PWM Buck Converter With Load-Adaptive Power Transistor Scaling Scheme Using Analog-Digital Hybrid Control for High Energy Efficiency in Implantable Biomedical Systems.

    PubMed

    Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik

    2015-12-01

    We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor.

  4. Comparison of Early versus Delayed Timing of Left Ventricular Assist Device Implantation as a Bridge-to-Transplantation: An Analysis of the UNOS Dataset

    PubMed Central

    Jin, Zhezhen; Clerkin, Kevin; Homma, Shunichi; Mancini, Donna M.

    2016-01-01

    Background Placement of left ventricular assist devices (LVAD) as a bridge-to-heart transplantation (HTx) has rapidly expanded due to organ donor shortage. However, the timing of LVAD implantation is variable and it remains unclear if earlier implantation improves survival. Methods We analyzed 14,187 adult candidates from the United Network of Organ Sharing database. Patients were classified by 3 treatment strategies including patients medically treated alone (MED, n=11,009), patients on LVAD support at listing (Early-LVAD, n=1588) and patients undergoing LVAD placement while awaiting HTx (Delayed-LVAD, n=1590). Likelihood of HTx and event-free survival were assessed in patients subcategorized by clinical strategies and UNOS status at listing. Results The device support strategy, despite the timing of placement, was not associated with increased likelihood of HTx compared to MED group. However, both LVAD implantation strategies showed better survival compared to MED group (Early-LVAD: HR 0.811 and 0.633, 95% CI 0.668-0.984 and 0.507-0.789, for 1A and 1B; p=0.034 and p<0.001, Delayed-LVAD: HR 0.553 and 0.696, 95% CI 0.415-0.736 and 0.571-0.847, for 1A and 1B; both p<0.001, respectively). Furthermore, there was no significant difference in survival between these LVAD implantation strategies in patients listed as 1B (p=0.500), although Early-LVAD implantation showed worse survival in patients listed as 1A (HR 1.467, 95% CI 1.076-2.000; p=0.015). Conclusion LVAD support strategies offer a safe bridge-to-HTx. Those candidates who receive urgent upfront LVAD implantation for HTx, and improve to 1B status, would achieve competitive survival with those who receive elective LVAD implantation. PMID:26618255

  5. Comparison of early versus delayed timing of left ventricular assist device implantation as a bridge-to-transplantation: An analysis of the UNOS dataset.

    PubMed

    Kitada, Shuichi; Schulze, P Christian; Jin, Zhezhen; Clerkin, Kevin; Homma, Shunichi; Mancini, Donna M

    2016-01-15

    Placement of left ventricular assist devices (LVAD) as a bridge-to-heart transplantation (HTx) has rapidly expanded due to organ donor shortage. However, the timing of LVAD implantation is variable and it remains unclear if earlier implantation improves survival. We analyzed 14,187 adult candidates from the United Network of Organ Sharing database. Patients were classified by 3 treatment strategies including patients medically treated alone (MED, n=11,009), patients on LVAD support at listing (Early-LVAD, n=1588) and patients undergoing LVAD placement while awaiting HTx (Delayed-LVAD, n=1590). Likelihood of HTx and event-free survival were assessed in patients subcategorized by clinical strategies and UNOS status at listing. The device support strategy, despite the timing of placement, was not associated with increased likelihood of HTx compared to MED group. However, both LVAD implantation strategies showed better survival compared to MED group (Early-LVAD: HR 0.811 and 0.633, 95% CI 0.668-0.984 and 0.507-0.789, for 1A and 1B; p=0.034 and p<0.001, Delayed-LVAD: HR 0.553 and 0.696, 95% CI 0.415-0.736 and 0.571-0.847, for 1A and 1B; both p<0.001, respectively). Furthermore, there was no significant difference in survival between these LVAD implantation strategies in patients listed as 1B (p=0.500), although Early-LVAD implantation showed worse survival in patients listed as 1A (HR 1.467, 95% CI 1.076-2.000; p=0.015). LVAD support strategies offer a safe bridge-to-HTx. Those candidates who receive urgent upfront LVAD implantation for HTx, and improve to 1B status, would achieve competitive survival with those who receive elective LVAD implantation. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  6. Early safety outcome following transcatheter aortic valve implantation: is the amount of contrast media used a matter of concern?

    PubMed

    Vontobel, Jan; Possner, Mathias; Schütz, Philipp; Müller, Beat; Taramasso, Maurizio; Binder, Roland K; Haueis, Sabine; Attinger-Toller, Adrian; Maisano, Francesco; Nietlispach, Fabian

    2015-01-01

    The study objective was to evaluate the impact of the amount of contrast medium used for transcatheter aortic valve implantation (TAVI) on short-term outcome. Patients undergoing TAVI are exposed to repeat contrast medium application both for preprocedural screening and during the TAVI procedure itself. Whether the amount of contrast media is associated with worse outcome is unclear. A total of 257 patients were included (median age 82.7 years) and divided into two groups with preserved and reduced kidney function (glomerular filtration rate <60 ml/min/1.73 m2), respectively. Total volume of contrast media administered during and within 5 days prior to TAVI was analysed. A combined early safety endpoint at 30 days was evaluated. The early safety endpoint was reached by 31 patients and acute kidney injury occurred in 22 patients. The median total volume of contrast media administered was 144 ml (interquartile range 81-225 ml). The amount of contrast did not independently predict the early safety endpoint in the overall population (odds ratio [OR] 0.93, 95% confidence interval [CI] 0.56 to 1.53, p = 0.774) and in subgroups with preserved and reduced kidney function. Change in creatinine was an independent strong predictor of the early safety endpoint in the overall population (OR 18.13, 95% CI 4.70 to 69.99, p <0.001), as well as in subgroups with preserved and reduced kidney function. The amount of contrast did not predict a change in creatinine within 72 hours following TAVI (r = 0.02, 95% CI -0.02 to 0.07, p = 0.368). Decreased kidney function after TAVI influences outcome. When rather small amounts of contrast media are used for screening and the TAVI procedure itself, the amount of contrast media seems not to be an independent predictor of outcome, further suggesting that decreased kidney function after TAVI is multifactorial.

  7. A longitudinal study of lexical and grammar development in deaf Italian children provided with early cochlear implantation.

    PubMed

    Chilosi, Anna Maria; Comparini, Alessandro; Scusa, Maria Flora; Orazini, Laura; Forli, Francesca; Cipriani, Paola; Berrettini, Stefano

    2013-01-01

    A growing number of studies on deaf children with cochlear implant (CI) document a significant improvement in receptive and expressive language skills after implantation, even if they show language delay when compared with normal-hearing peers. Data on language acquisition in CI Italian children are still scarce and limited to only certain aspects of language. The purpose of this study is to prospectively describe the trajectories of language development in early CI Italian children, with particular attention to the transition from first words to combinatorial speech and to acquisition of complex grammar in a language with rich morphology, such as Italian. Six children, with profound prelingual deafness, provided with CI, between 16 and 24 months of age were prospectively assessed and followed over a mean period of up to 34.8 months postimplant. During follow-up, each child received between four to five individual language evaluations through a combination of indirect procedures (parent reports of early lexical and grammar development) and direct ones (administration of standardized receptive and expressive language tests with Italian norms and collection of spontaneous language samples). In relation to chronological age, the acquisition of expressive vocabulary was delayed. However, considering the duration of hearing experience, most CI participants showed an earlier start and faster growth of expressive rather than receptive vocabulary in comparison with typically developing children. This quite atypical result persisted right up until the end of the follow-up. The acquisition of expressive grammar was delayed relative to chronological age, though all but one CI participant achieved the expected grammar level after approximately 3 years of CI use. In addition, the rate of grammar acquisition was not homogeneous during development, showing two different paces: one comparable with normal hearing in the transition from holophrastic to primitive combinatorial speech

  8. Early outcome of patients undergoing transcatheter aortic valve implantation (TAVI): The Auckland City Hospital experience 2011-2015.

    PubMed

    Wu, Sylvia S Y; Wang, Tom Kai Ming; Nand, Parma; Ramanathan, Tharumenthiran; Webster, Mark; Stewart, Jim

    2016-01-08

    Transcatheter aortic valve implantation (TAVI) is an alternative to surgical aortic valve replacement (AVR) in high-risk patients. We report the initial TAVI experience at Auckland City Hospital. The records of patients undergoing TAVI between 2011 and 2015 at Auckland City Hospital were reviewed. We report the procedural success and outcome, including major adverse events (death, stroke, myocardial infarction, bleeding, vascular complications and rehospitalisations), degree of aortic regurgitation and symptom status up to 1-year follow-up. Mean age was 80.7 years and mean Euroscore II and Society of Thoracic Surgeons' scores were 8.2% and 6.3% respectively; 50% had undergone previous cardiac surgery. Successful deployment of the valve was achieved in all patients. The cumulative mortality rates at 30 days, 6 months and 1 year were 2.4%, 6.1% and 12.2% and cumulative stroke rates 1.2%, 3% and 8.2% respectively. Severe aortic regurgitation occurred in 2.3% TAVI is available in the New Zealand public hospital system for patients who are high-risk candidates for AVR. Early results are excellent and indicate that the technology is being used appropriately, according to current access criteria. If the early cost effectiveness data are confirmed, the indications for TAVI may widen.

  9. Early Cochlear Implant Experience and Emotional Functioning during Childhood: Loneliness in Middle and Late Childhood

    ERIC Educational Resources Information Center

    Schorr, Efrat A.

    2006-01-01

    The importance of early intervention for children with hearing loss has been demonstrated persuasively in areas including speech perception and production and spoken language. The present research shows that feelings of loneliness, a significant emotional outcome, are affected by the age at which children receive intervention with cochlear…

  10. Decreased Knee Joint Loading Associated With Early Knee Osteoarthritis After Anterior Cruciate Ligament Injury.

    PubMed

    Wellsandt, Elizabeth; Gardinier, Emily S; Manal, Kurt; Axe, Michael J; Buchanan, Thomas S; Snyder-Mackler, Lynn

    2016-01-01

    Anterior cruciate ligament (ACL) injury predisposes individuals to early-onset knee joint osteoarthritis (OA). Abnormal joint loading is apparent after ACL injury and reconstruction. The relationship between altered joint biomechanics and the development of knee OA is unknown. Altered knee joint kinetics and medial compartment contact forces initially after injury and reconstruction are associated with radiographic knee OA 5 years after reconstruction. Case-control study; Level of evidence, 3. Individuals with acute, unilateral ACL injury completed gait analysis before (baseline) and after (posttraining) preoperative rehabilitation and at 6 months, 1 year, and 2 years after reconstruction. Surface electromyographic and knee biomechanical data served as inputs to an electromyographically driven musculoskeletal model to estimate knee joint contact forces. Patients completed radiographic testing 5 years after reconstruction. Differences in knee joint kinetics and contact forces were compared between patients with and those without radiographic knee OA. Patients with OA walked with greater frontal plane interlimb differences than those without OA (nonOA) at baseline (peak knee adduction moment difference: 0.00 ± 0.08 N·m/kg·m [nonOA] vs -0.15 ± 0.09 N·m/kg·m [OA], P = .014; peak knee adduction moment impulse difference: -0.001 ± 0.032 N·m·s/kg·m [nonOA] vs -0.048 ± 0.031 N·m·s/kg·m [OA], P = .042). The involved limb knee adduction moment impulse of the group with osteoarthritis was also lower than that of the group without osteoarthritis at baseline (0.087 ± 0.023 N·m·s/kg·m [nonOA] vs 0.049 ± 0.018 N·m·s/kg·m [OA], P = .023). Significant group differences were absent at posttraining but reemerged 6 months after reconstruction (peak knee adduction moment difference: 0.02 ± 0.04 N·m/kg·m [nonOA] vs -0.06 ± 0.11 N·m/kg·m [OA], P = .043). In addition, the OA group walked with lower peak medial compartment contact forces of the involved limb

  11. Early failure of total hip replacements implanted at distant hospitals to reduce waiting lists.

    PubMed Central

    Ciampolini, Jac; Hubble, Matthew J. W.

    2005-01-01

    AIM: In the years 1990-1993, in an effort to reduce waiting-list time, a small number of patients were sent from Exeter to hospitals in London to undergo elective total hip replacement. No medium- or long-term follow-up was arranged. Our aim was to audit the outcome of these hip replacements. PATIENTS AND METHODS: Review of the records of the referring medical practices, Regional Health Authority, local orthopaedic hospital and the distant centres at which the surgery was performed identified 31 cases. A total of 27 hip replacements in 24 patients were available for clinical and radiological review. RESULTS: 12 (44%) hips have so far required revision surgery, at a mean of 6.5 years. Of these, three (11%) have been for deep infection. A further three hips (11%) are radiologically loose and are being closely monitored. Two patients (7%) suffered permanent sciatic nerve palsy. CONCLUSIONS: Patients whose surgery was performed locally over a similar time period have a published failure rate of only 4.9%. This difference is highly statistically significant (P < 0.001). The causes for such a difference in outcome were analysed and include surgical technique, implant selection and absence of follow-up. In the light of this evidence, we would like to urge the government to address waiting list problems by investing in the local infrastructure. Expanding those facilities where properly audited and fully accountable surgeons operate must be the way forward. PMID:15720905

  12. Early Gains in Renal Function Following Implantation of HeartMate II Left Ventricular Assist Devices May Not Persist to One Year.

    PubMed

    Hasin, Tal; Grupper, Avishay; Dillon, John J; Maleszewski, Joseph J; Li, Zhuo; Topilsky, Yan; Frantz, Robert P; Edwards, Brooks S; Pereira, Naveen L; Maltais, Simon; Stulak, John M; Joyce, Lyle; Daly, Richard; Park, Soon J; Kushwaha, Sudhir S

    Renal function improves early after left ventricular assist device (LVAD) implantation but later decline has been observed. We sought to determine the occurrence and evaluate possible causes for this decline. In 62 consecutive patients with HeartMateII LVAD with available calculated glomerular filtration rate (GFR, ml/min/1.73 m) 1 year after implant, GFR was assessed repeatedly and possible predictors for decline from 3 to 12 months were investigated. Post-mortem renal specimens for patients supported with an LVAD were evaluated. GFR 54.5 ± 19.5 at admission increased to 66.4 ± 22.3 preoperatively and to 79.2 ± 30.1 ~1 month after implantation. Subsequently at ~3 months GFR declined to 74.7 ± 25.4, at ~6 months to 68.8 ± 23.1, and ~1 year after implant to 63.9 ± 17.7. Glomerular filtration rate at 1 year was significantly lower (p < 0.0001, p < 0.0001, p = 0.005) than GFR 1, 3, and 6 months after implant. Early rise in GFR after surgery was not associated with late decline. Shorter bypass time (β = -0.09, p = 0.048) and higher albumin 3 months after LVAD (β = 14.4, p = 0.025) were significantly associated with less later decline in GFR. Arteriosclerosis was identified in autopsy renal specimens. In conclusion, early gains in renal function after LVAD implant are not sustained in many patients. Patient, device, and operative factors may influence long-term renal function in these patients.

  13. Multiscale Analyses of the Bone-implant Interface

    PubMed Central

    Cha, J.Y.; Pereira, M.D.; Smith, A.A.; Houschyar, K.S.; Yin, X.; Mouraret, S.; Brunski, J.B.

    2015-01-01

    Implants placed with high insertion torque (IT) typically exhibit primary stability, which enables early loading. Whether high IT has a negative impact on peri-implant bone health, however, remains to be determined. The purpose of this study was to ascertain how peri-implant bone responds to strains and stresses created when implants are placed with low and high IT. Titanium micro-implants were inserted into murine femurs with low and high IT using torque values that were scaled to approximate those used to place clinically sized implants. Torque created in peri-implant tissues a distribution and magnitude of strains, which were calculated through finite element modeling. Stiffness tests quantified primary and secondary implant stability. At multiple time points, molecular, cellular, and histomorphometric analyses were performed to quantitatively determine the effect of high and low strains on apoptosis, mineralization, resorption, and collagen matrix deposition in peri-implant bone. Preparation of an osteotomy results in a narrow zone of dead and dying osteocytes in peri-implant bone that is not significantly enlarged in response to implants placed with low IT. Placing implants with high IT more than doubles this zone of dead and dying osteocytes. As a result, peri-implant bone develops micro-fractures, bone resorption is increased, and bone formation is decreased. Using high IT to place an implant creates high interfacial stress and strain that are associated with damage to peri-implant bone and therefore should be avoided to best preserve the viability of this tissue. PMID:25628271

  14. Implantation of preadipocyte-loaded hyaluronic acid-based scaffolds into nude mice to evaluate potential for soft tissue engineering.

    PubMed

    Hemmrich, Karsten; von Heimburg, Dennis; Rendchen, Raoul; Di Bartolo, Chiara; Milella, Eva; Pallua, Norbert

    2005-12-01

    The reconstruction of soft tissue defects following extensive deep burns or tumor resections remains an unresolved problem in plastic and reconstructive surgery since adequate implant materials are still not available. Preadipocytes, immature precursor cells found between mature adipocytes in adipose tissue, are a potential material for soft tissue engineering since they can proliferate and differentiate into adipose tissue after transplantation. In previous studies, we identified hyaluronan benzyl ester (HYAFF 11) sponges to be promising carrier matrices. This study now evaluates, in vitro and in vivo, a new sponge architecture with pores of 400 microm either made of plain HYAFF 11 or HYAFF 11 coated with the extracellular matrix glycosaminoglycan hyaluronic acid. Human preadipocytes were isolated, seeded onto carriers and implanted into nude athymic mice. Explants harvested after 3, 8, and 12 weeks were examined for macroscopical appearance, thickness, weight, pore structure, histology, and immunohistochemistry. Compared to previous studies, we found better penetration of cells into both types of scaffolds, with more extensive formation of new vessels throughout the construct but with only minor adipose tissue. Our encouraging results contribute towards a better seeded and vascularised scaffold but also show that the enhancement of adipogenic conversion of preadipocytes remains a major task for further in vivo experiments.

  15. Oral Health-related quality of life and clinical outcomes of immediately or delayed loaded implants in the rehabilitation of edentulous jaws: a retrospective comparative study.

    PubMed

    Cosola, Saverio; Marconcini, Simone; Giammarinaro, Enrica; Poli, Gian L; Covani, Ugo; Barone, Antonio

    2018-04-16

    Patient-centred outcomes are being given great attention by the dental scientific community. The Oral Health Impact Profile -14 questionnaire (OHIP-14) has been introduced to address patients' success criteria when describing the impact of oral rehabilitations on quality of life (OHrQoL). Thirty-five patients wearing a full-arch implant-prosthesis being in place between 4 and 6 years before this analysis were considered eligible and then enrolled in the present retrospective study. According to their prosthetic anamnesis, two groups were defined: delayed loading group (IL-group) and immediate loading group (IL-group). At the moment of analysis, clinical and radiographic parameters were collected, and patients were asked to complete the Oral Health Impact Profile -14 questionnaire (OHIP-14) in order to measure their OHrQoL. Independent t-test showed total OHIP-14 scores to be not significantly different between groups; however, the domains "Functional limitation" and "physical disability" resulted significantly higher in patients within the DL-group. On the contrary, social disability was higher in the IL-group. When the comparison was performed taking sex into account, no significant differences between groups were highlighted. Instead, the stratification for years of follow-up led to significant evidences. When the follow-up was shorter (less-than-5 years), the functional limitation reported scores were higher. Within the limitations of this study, the analysis supports the absence of significant differences between immediate loading and delayed loading full-arch protocol in term of clinical, radiological parameters and OHrQoL.

  16. Changing Trends within the Population of Children Who Are Deaf or Hard of Hearing in Flanders (Belgium): Effects of 12 Years of Universal Newborn Hearing Screening, Early Intervention, and Early Cochlear Implantation

    ERIC Educational Resources Information Center

    De Raeve, Leo; Lichtert, Guido

    2012-01-01

    The purpose of this study is to show the changing trends within the population of children who are deaf and hard of hearing in Belgium over the last 12 years. The combination of Universal Newborn Hearing Screening programs, early intervention, and cochlear implants have tremendously influenced the education and support of children who are deaf or…

  17. Front-loading with clopidogrel plus aspirin followed by dual antiplatelet therapy in the prevention of early stroke recurrence.

    PubMed

    Censori, Bruno

    2014-07-01

    Dual antiplatelet therapy with aspirin plus clopidogrel is not recommended for secondary stroke prevention because of lack of effectiveness and increased hemorrhagic risk. Recent studies show that in patients with a very recent transient ischemic attack or minor ischemic stroke loading with 300 mg clopidogrel plus aspirin, followed by clopidogrel 75 mg plus aspirin once daily for up to 90 days significantly decreases the rate of recurrent stroke, especially strokes that occur within few days from the event that led to medical attention, without an increase in severe bleedings. This article reviews the pharmacokinetics and pharmacodynamics of clopidogrel, focusing on loading doses, and summarizes the results of the studies that have shown the effectiveness of the front-loading approach in the early secondary prevention of stroke.

  18. Classic debates in selective attention: early vs late, perceptual load vs dilution, mean RT vs measures of capacity.

    PubMed

    Nelson, Michael D; Crisostomo, Marisa; Khericha, Alifiya; Russo, Francis; Thorne, Gary L

    2012-01-01

    We briefly summarize two important debates regarding selective attention (early vs late selection; perceptual load vs distractor dilution). Also, we report the results of an attempt to replicate Lavie (1995, Journal of Experimental Psychology: Human Perception and Performance 21 451-468). We suggest that measures capable of characterizing the capacity of information processing systems (compared to reporting only mean reaction time) could add great clarity to this literature.

  19. Relationship between early-life stress load and sleep in psychiatric outpatients: a sleep diary and actigraphy study.

    PubMed

    Schäfer, Valérie; Bader, Klaus

    2013-08-01

    The present study aimed to investigate whether stress experienced early in life is associated with actigraphic and subjective sleep measures in a sample of adult psychiatric outpatients. A total of 48 psychiatric outpatients completed self-report questionnaires assessing current depression, current anxiety symptoms and stress load during childhood (before the age of 13 years), adolescence (between the age of 13 and 18 years) and adulthood (between the age of 19 and current age). Sleep-related activity was measured using 24-h wrist actigraphy over a 7-day period at home, during which participants also kept a sleep diary. High stress load in childhood, but not in adolescence, was associated with shortened actigraphically assessed total sleep time, prolonged sleep onset latency, decreased sleep efficiency and an increased number of body movements in sleep, even after accounting for the effects of later occurring stress and psychopathological symptoms such as depression and anxiety scores. Unexpectedly, no significant associations between early-life stress load and subjective sleep measures were found. Results are consistent with findings from previous studies indicating an association between childhood adversities and higher levels of nocturnal activity. The findings suggest that high stress load during childhood might be a vulnerability factor for sleep continuity problems in adulthood. Copyright © 2012 John Wiley & Sons, Ltd.

  20. Microbiological outcome of two screw-shaped titanium implant systems placed following a split-mouth randomised protocol, at the 12th year of follow-up after loading.

    PubMed

    Van Assche, Nele; Pittayapat, Pisha; Jacobs, Reinhilde; Pauwels, Martine; Teughels, Wim; Quirynen, Marc

    2011-01-01

    To compare the subgingival microbiota around two differently designed implant systems that were in function for more than 12 years in a randomised split-mouth study design, and to compare the outcome with natural dentition. A total of 18 partially edentulous patients received at least two TiOblast™ (Astra Tech) and two Brånemark (Nobel Biocare) implants following a split-mouth design. At the last follow-up visit, periodontal parameters (probing depth, bleeding on probing and plaque) were recorded and intraoral radiographs were taken to calculate bone loss. Subgingival plaque samples were collected for culture, qPCR and checkerboard DNA-DNA hybridisation analysis. These data were related to implant design and bone loss. This study setup allowed a comparison of 34 Astra Tech (Impl A) with 32 Brånemark (Impl B) implants. During the 12-year follow up, five patients dropped out. One Brånemark implant was lost before abutment connection in a dropout patient. Mean bone loss between loading and year 12 was 0.7 mm (range: -0.8-5.8) (Impl A), and 0.4 mm (range: -1.1-4.1) (Impl B). No significant microbiological differences (qualitative and quantitative) could be observed between both implant types. Compared to teeth, subgingival plaque samples from implants did not reach the concentration of pathogens, even after 12 years of function. These data show that both implant systems (with differences in macro-design and surface characteristics), in patients with good oral hygiene and a stable periodontal condition, can maintain a successful treatment outcome without significant subgingival microbiological differences after 12 years of loading. The presence of periodontopathogens did not necessarily result in bone loss.

  1. The unsuitability of implantable Doppler probes for the early detection of renal vascular complications – a porcine model for prevention of renal transplant loss

    PubMed Central

    Jespersen, Bente; Møldrup, Ulla; Keller, Anna K.

    2017-01-01

    Background Vascular occlusion is a rare, but serious complication after kidney transplantation often resulting in graft loss. We therefore aimed to develop an experimental porcine model for stepwise reduction of the renal venous blood flow and to compare an implantable Doppler probe and microdialysis for fast detection of vascular occlusion. Methods In 20 pigs, implantable Doppler probes were placed on the renal artery and vein and a microdialysis catheter was placed in the renal cortex. An arterial flowprobe served as gold standard. Following two-hour baseline measurements, the pigs were randomised to stepwise venous occlusion, complete venous occlusion, complete arterial occlusion or controls. Results All parameters were stable through baseline measurements. Glutamate and lactate measured by microdialysis increased significantly (p = 0.02 and p = 0.03 respectively) 30 minutes after a 2/3 (66%) reduction in renal blood flow. The implantable Doppler probe was not able to detect flow changes until there was total venous occlusion. Microdialysis detected changes in local metabolism after both arterial and venous occlusion; the implantable Doppler probe could only detect vascular occlusions on the vessel it was placed. Conclusions We developed a new model for stepwise renal venous blood flow occlusion. Furthermore, the first comparison of the implantable Doppler probe and microdialysis for detection of renal vascular occlusions was made. The implantable Doppler probe could only detect flow changes after a complete occlusion, whereas microdialysis detected changes earlier, and could detect both arterial and venous occlusion. Based on these results, the implantable Doppler probe for early detection of vascular occlusions cannot be recommended. PMID:28542429

  2. Decreased Knee Joint Loading Associated With Early Knee Osteoarthritis After Anterior Cruciate Ligament Injury

    PubMed Central

    Wellsandt, Elizabeth; Gardinier, Emily S.; Manal, Kurt; Axe, Michael J.; Buchanan, Thomas S.; Snyder-Mackler, Lynn

    2015-01-01

    Background Anterior cruciate ligament (ACL) injury predisposes individuals to early-onset knee joint osteoarthritis (OA). Abnormal joint loading is apparent after ACL injury and reconstruction. The relationship between altered joint biomechanics and the development of knee OA is unknown. Hypothesis Altered knee joint kinetics and medial compartment contact forces initially after injury and reconstruction are associated with radiographic knee OA 5 years after reconstruction. Study Design Case-control study; Level of evidence, 3. Methods Individuals with acute, unilateral ACL injury completed gait analysis before (baseline) and after (posttraining) preoperative rehabilitation and at 6 months, 1 year, and 2 years after reconstruction. Surface electromyographic and knee biomechanical data served as inputs to an electromyographically driven musculoskeletal model to estimate knee joint contact forces. Patients completed radiographic testing 5 years after reconstruction. Differences in knee joint kinetics and contact forces were compared between patients with and those without radiographic knee OA. Results Patients with OA walked with greater frontal plane interlimb differences than those without OA (nonOA) at baseline (peak knee adduction moment difference: 0.00 ± 0.08 N·m/kg·m [nonOA] vs −0.15 ± 0.09 N·m/kg·m [OA], P = .014; peak knee adduction moment impulse difference: −0.001 ± 0.032 N·m·s/kg·m [nonOA] vs −0.048 ± 0.031 N·m·s/kg·m [OA], P = .042). The involved limb knee adduction moment impulse of the group with osteoarthritis was also lower than that of the group without osteoarthritis at baseline (0.087 ± 0.023 N·m·s/kg·m [nonOA] vs 0.049 ± 0.018 N·m·s/kg·m [OA], P = .023). Significant group differences were absent at posttraining but reemerged 6 months after reconstruction (peak knee adduction moment difference: 0.02 ± 0.04 N·m/kg·m [nonOA] vs −0.06 ± 0.11 N·m/kg·m [OA], P = .043). In addition, the OA group walked with lower peak

  3. Thermography Inspection for Early Detection of Composite Damage in Structures During Fatigue Loading

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N.; Burke, Eric R.; Parker, F. Raymond; Seebo, Jeffrey P.; Wright, Christopher W.; Bly, James B.

    2012-01-01

    Advanced composite structures are commonly tested under controlled loading. Understanding the initiation and progression of composite damage under load is critical for validating design concepts and structural analysis tools. Thermal nondestructive evaluation (NDE) is used to detect and characterize damage in composite structures during fatigue loading. A difference image processing algorithm is demonstrated to enhance damage detection and characterization by removing thermal variations not associated with defects. In addition, a one-dimensional multilayered thermal model is used to characterize damage. Lastly, the thermography results are compared to other inspections such as non-immersion ultrasonic inspections and computed tomography X-ray.

  4. Early serum interleukin-8 evaluation may prove useful in localizing abnormally implanted human gestations after in vitro fertilization.

    PubMed

    Morelli, Sara S; Keegan, Debbra A; Krey, Lewis C; Katz, Joseph; Liu, Mengling; Noyes, Nicole

    2008-12-01

    To determine whether early measurement of the serum cytokines interleukin-2 receptor (IL-2R), IL-6, and IL-8 along with human chorionic gonadotropin (hCG) and progesterone (P(4)) can differentiate an ectopic from an intrauterine gestation. Retrospective analysis. University-based fertility center. 75 women who underwent treatment with in vitro fertilization (IVF) and subsequently had an ectopic gestation (n = 15), spontaneous abortion (SAB) (n = 30), or term delivery (TD) (n = 30). Serum samples were obtained 14 (day 28) and 21 (day 35) days after oocyte retrieval. Serum concentrations of IL-2R, IL-6, IL-8, P(4), and hCG. Median hCG readings on day 28 and day 35 were statistically significantly lower in the ectopic gestation group than in those with spontaneous abortion or term delivery. On day 28, median IL-8 levels were lower in the ectopic gestation group when compared with all intrauterine gestations combined. No statistically significant differences in IL-2R or IL-6 levels were noted between groups. Despite P(4) supplementation, median day-35 P(4) levels were lower in ectopic gestation than in the spontaneous abortion and term delivery cycles. In the setting of a rise or plateau in hCG levels, low day-28 IL-8 and day-35 P(4) levels suggested an extrauterine implantation. This assay combination may facilitate earlier diagnosis of an ectopic gestation when pregnancy location is unclear.

  5. Constant strain rate and peri-implant bone modeling: an in vivo longitudinal micro-CT analysis.

    PubMed

    De Smet, Els; Jaecques, Siegfried V N; Wevers, Martine; Sloten, Jos Vander; Naert, Ignace E

    2013-06-01

    Strain, frequency, loading time, and strain rate, among others, determine mechanical parameters in osteogenic loading. We showed a significant osteogenic effect on bone mass (BM) by daily peri-implant loading at 1.600µε.s(-1) after 4 weeks. To study the peri-implant osteogenic effect of frequency and strain in the guinea pig tibia by in vivo longitudinal micro-computed tomography (CT) analysis. One week after implant installation in both hind limb tibiae, one implant was loaded daily for 10' during 4 weeks, while the other served as control. Frequencies (3, 10, and 30Hz) and strains varied alike in the three series to keep the strain rate constant at 1.600µε.s(-1) . In vivo micro-CT scans were taken of both tibiae: 1 week after implantation but before loading (v1) and after 2 (v2) and 4 weeks (v3) of loading as well as postmortem (pm). BM (BM (%) bone-occupied area fraction) was calculated as well as the difference between test and control sides (delta BM) RESULTS: All implants (n=78) were clinically stable at 4 weeks. Significant increase in BM was measured between v1 and v2 (p<.0001) and between v1 and v3 (p<.0001). A significant positive effect of loading on delta BM was observed in the distal peri-implant marrow 500 Region of Interest already 2 weeks after loading (p=.01) and was significantly larger (11%) in series 1 compared with series 2 (p=.006) and 3 (p=.016). Within the constraints of constant loading time and strain rate, the effect of early implant loading on the peri-implant bone is strongly dependent on strain and frequency. This cortical bone model has shown to be most sensitive for high force loading at low frequency. © 2011 Wiley Periodicals, Inc.

  6. Assessment of a polyelectrolyte multilayer film coating loaded with BMP-2 on titanium and PEEK implants in the rabbit femoral condyle

    PubMed Central

    Guillot, R.; Pignot-Paintrand, I.; Lavaud, J.; Decambron, A.; Bourgeois, E.; Josserand, V.; Logeart-Avramoglou, D.; Viguier, E.; Picart, C.

    2016-01-01

    The aim of this study was to evaluate the osseointegration of titanium implants (Ti-6Al-4V, noted here TA6V) and poly(etheretherketone) PEEK implants induced by a BMP-2-delivering surface coating made of polyelectrolyte multilayer films. The in vitro bioactivity of the polyelectrolyte film-coated implants was assessed using the alkaline phosphatase assay. BMP-2-coated TA6V and PEEK implants with a total dose of 9.3 µg of BMP-2 were inserted into the femoral condyles of New Zealand white rabbits and compared to uncoated implants. Rabbits were sacrificed 4 and 8 weeks after implantation. Histomorphometric analyses on TA6V and PEEK implants and microcomputed tomography on PEEK implants revealed that the bone-to-implant contact and bone area around the implants were significantly lower for the BMP-2-coated implants than for the bare implants. This was confirmed by scanning electron microscopy imaging. This difference was more pronounced at 4 weeks in comparison to the 8-week time point. However, bone growth inside the hexagonal upper hollow cavity of the screws was higher in the case of the BMP-2 coated implants. Overall, this study shows that a high dose of BMP-2 leads to localized and temporary bone impairment, and that the dose of BMP-2 delivered at the surface of an implant needs to be carefully optimized. PMID:26965394

  7. New phenotypic aspects of the decidual spiral artery wall during early post-implantation mouse pregnancy

    SciT

    Elia, Artemis; Charalambous, Fotini; Georgiades, Pantelis, E-mail: pgeor@ucy.ac.cy

    Highlights: Black-Right-Pointing-Pointer Spiral artery (SA) wall remodeling (SAR) is ill-defined and clinically important. Black-Right-Pointing-Pointer SA muscular phenotype prior to and during SAR in mice is underexplored. Black-Right-Pointing-Pointer SA muscular wall consists of contractile and non-contractile components. Black-Right-Pointing-Pointer SA wall non-contractile component may be synthetic smooth muscle. Black-Right-Pointing-Pointer Timing and extent of SA wall contractile component loss is revealed. -- Abstract: During pregnancy the walls of decidual spiral arteries (SAs) undergo clinically important structural modifications crucial for embryo survival/growth and maternal health. However, the mechanisms of SA remodeling (SAR) are poorly understood. Although an important prerequisite to this understanding is knowledgemore » about the phenotype of SA muscular wall prior to and during the beginning of mouse SAR, this remains largely unexplored and was the main aim of this work. Using histological and immunohistochemical techniques, this study shows for the first time that during early mouse gestation, from embryonic day 7.5 (E7.5) to E10.5, the decidual SA muscular coat is not a homogeneous structure, but consists of two concentric layers. The first is a largely one cell-thick sub-endothelial layer of contractile mural cells (positive for {alpha}-smooth muscle actin, calponin and SM22{alpha}) with pericyte characteristics (NG2 positive). The second layer is thicker, and evidence is presented that it may be of the synthetic/proliferative smooth muscle phenotype, based on absence ({alpha}-smooth muscle actin and calponin) or weak (SM22{alpha}) expression of contractile mural cell markers, and presence of synthetic smooth muscle characteristics (expression of non-muscle Myosin heavy chain-IIA and of the cell proliferation marker PCNA). Importantly, immunohistochemistry and morphometrics showed that the contractile mural cell layer although prominent at E7

  8. Report on the Clinical Outcomes of Permanent Breast Seed Implant for Early-Stage Breast Cancers

    SciT

    Pignol, Jean-Philippe, E-mail: j.p.pignol@erasmusmc.nl; Radiation Oncology Department, Erasmus Medical Center Cancer Institute, Rotterdam; Caudrelier, Jean-Michel

    Purpose: Permanent breast seed implant is an accelerated partial breast irradiation technique realizing the insertion of {sup 103}Pd seeds in the seroma after lumpectomy. We report the 5-year efficacy and tolerance for a cohort, pooling patients from 3 clinical trials. Methods and Materials: The trials accrued postmenopausal patients with infiltrating ductal carcinoma or ductal carcinoma in situ ≤3 cm and clear surgical margins, who were node negative, and had a planning target volume <120 cm{sup 3}. The outcomes included overall and disease-free survival and local and contralateral recurrence at 5 years. The true local recurrence rate was compared using 2-tailed paired t testsmore » for estimates calculated using the Tufts University ipsilateral breast tumor recurrence and Memorial Sloan Kettering ductal carcinoma in situ nomograms. Results: The cohort included 134 patients, and the observed local recurrence rate at a median follow-up period of 63 months was 1.2% ± 1.2%, similar to the estimate for whole breast irradiation (P=.23), significantly better than for surgery alone (relative risk 0.27; P<.001), and significantly lower than contralateral recurrence (relative risk 0.33; P<.001). The 5-year overall survival rate was 97.4% ± 1.9%, and the disease-free survival rate was 96.4% ± 2.1%. At 2 months, 42% of the patients had erythema, 20% induration, and 16% moist desquamation. The rate of mainly grade 1 telangiectasia was 22.4% at 2 years and 24% at 5 years. The rate of asymptomatic induration was 23% at 2 years and 40% at 5 years. Conclusions: The 5-year data suggest that permanent breast seed implantation is a safe accelerated partial breast irradiation option after lumpectomy for early-stage breast cancer with a tolerance profile similar to that of whole breast irradiation.« less

  9. Low elastic modulus Ti-Ta alloys for load-bearing permanent implants: enhancing the biodegradation resistance by electrochemical surface engineering.

    PubMed

    Kesteven, Jazmin; Kannan, M Bobby; Walter, Rhys; Khakbaz, Hadis; Choe, Han-Choel

    2015-01-01

    In this study, the in vitro degradation behaviour of titanium-tantalum (Ti-Ta) alloys (10-30 wt.% Ta) was investigated and compared with conventional implant materials, i.e., commercially pure titanium (Cp-Ti) and titanium-aluminium-vanadium (Ti6Al4V) alloy. Among the three Ti-Ta alloys studied, the Ti20Ta (6.3×10(-4) mm/y) exhibited the lowest degradation rate, followed by Ti30Ta (1.2×10(-3) mm/y) and Ti10Ta (1.4×10(-3) mm/y). All the Ti-Ta alloys exhibited lower degradation rate than that of Cp-Ti (1.8×10(-3) mm/y), which suggests that Ta addition to Ti is beneficial. As compared to Ti6Al4V alloy (8.1×10(-4) mm/y), the degradation rate of Ti20Ta alloy was lower by ~22%. However, the Ti30Ta alloy, which has closer elastic modulus to that of natural bone, showed ~48% higher degradation rate than that of Ti6Al4V alloy. Hence, to improve the degradation performance of Ti30Ta alloy, an intermediate thin porous layer was formed electrochemically on the alloy followed by calcium phosphate (CaP) electrodeposition. The coated Ti30Ta alloy (3.8×10(-3) mm/y) showed ~53% lower degradation rate than that of Ti6Al4V alloy. Thus, the study suggests that CaP coated Ti30Ta alloy can be a viable material for load-bearing permanent implants. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Lava heating and loading of ice sheets on early Mars: Predictions for meltwater generation, groundwater recharge, and resulting landforms

    NASA Astrophysics Data System (ADS)

    Cassanelli, James P.; Head, James W.

    2016-06-01

    Recent modeling studies of the early Mars climate predict a predominantly cold climate, characterized by the formation of regional ice sheets across the highland areas of Mars. Formation of the predicted "icy highlands" ice sheets is coincident with a peak in the volcanic flux of Mars involving the emplacement of the Late Noachian - Early Hesperian ridged plains unit. We explore the relationship between the predicted early Mars "icy highlands" ice sheets, and the extensive early flood volcanism to gain insight into the surface conditions prevalent during the Late Noachian to Early Hesperian transition period. Using Hesperia Planum as a type area, we develop an ice sheet lava heating and loading model. We quantitatively assess the thermal and melting processes involved in the lava heating and loading process following the chronological sequence of lava emplacement. We test a broad range of parameters to thoroughly constrain the lava heating and loading process and outline predictions for the formation of resulting geological features. We apply the theoretical model to a study area within the Hesperia Planum region and assess the observed geology against predictions derived from the ice sheet lava heating and loading model. Due to the highly cratered nature of the Noachian highlands terrain onto which the volcanic plains were emplaced, we predict highly asymmetrical lava loading conditions. Crater interiors are predicted to accumulate greater thicknesses of lava over more rapid timescales, while in the intercrater plains, lava accumulation occurs over longer timescales and does not reach great thicknesses. We find that top-down melting due to conductive heat transfer from supraglacial lava flows is generally limited when the emplaced lava flows are less than ∼10 m thick, but is very significant at lava flow thicknesses of ∼100 m or greater. We find that bottom-up cryosphere and ice sheet melting is most likely to occur within crater interiors where lavas

  11. Early diagnostic of concurrent gear degradation processes progressing under time-varying loads

    NASA Astrophysics Data System (ADS)

    Guilbault, Raynald; Lalonde, Sébastien

    2016-08-01

    This study develops a gear diagnostic procedure for the detection of multi- and concurrent degradation processes evolving under time-varying loads. Instead of a conventional comparison between a descriptor and an alarm level, this procedure bases its detection strategy on a descriptor evolution tracking; a lasting descriptor increase denotes the presence of ongoing degradation mechanisms. The procedure works from time domain residual signals prepared in the frequency domain, and accepts any gear conditions as reference signature. To extract the load fluctuation repercussions, the procedure integrates a scaling factor. The investigation first examines a simplification assuming a linear connection between the load and the dynamic response amplitudes. However, while generally valuable, the precision losses associated with large load variations may mask the contribution of tiny flaws. To better reflect the real non-linear relation, the paper reformulates the scaling factor; a power law with an exponent value of 0.85 produces noticeable improvements of the load effect extraction. To reduce the consequences of remaining oscillations, the procedure also includes a filtering phase. During the validation program, a synthetic wear progression assuming a commensurate relation between the wear depth and friction assured controlled evolutions of the surface degradation influence, whereas the fillet crack growth remained entirely determined by the operation conditions. Globally, the tested conditions attest that the final strategy provides accurate monitoring of coexisting isolated damages and general surface deterioration, and that its tracking-detection capacities are unaffected by severe time variations of external loads. The procedure promptly detects the presence of evolving abnormal phenomena. The tests show that the descriptor curve shapes virtually describe the constant wear progression superimposed on the crack length evolution. At the tooth fracture, the mean values of

  12. Tools for Early Prediction of Drug Loading in Lipid-Based Formulations

    PubMed Central

    2015-01-01

    Identification of the usefulness of lipid-based formulations (LBFs) for delivery of poorly water-soluble drugs is at date mainly experimentally based. In this work we used a diverse drug data set, and more than 2,000 solubility measurements to develop experimental and computational tools to predict the loading capacity of LBFs. Computational models were developed to enable in silico prediction of solubility, and hence drug loading capacity, in the LBFs. Drug solubility in mixed mono-, di-, triglycerides (Maisine 35-1 and Capmul MCM EP) correlated (R2 0.89) as well as the drug solubility in Carbitol and other ethoxylated excipients (PEG400, R2 0.85; Polysorbate 80, R2 0.90; Cremophor EL, R2 0.93). A melting point below 150 °C was observed to result in a reasonable solubility in the glycerides. The loading capacity in LBFs was accurately calculated from solubility data in single excipients (R2 0.91). In silico models, without the demand of experimentally determined solubility, also gave good predictions of the loading capacity in these complex formulations (R2 0.79). The framework established here gives a better understanding of drug solubility in single excipients and of LBF loading capacity. The large data set studied revealed that experimental screening efforts can be rationalized by solubility measurements in key excipients or from solid state information. For the first time it was shown that loading capacity in complex formulations can be accurately predicted using molecular information extracted from calculated descriptors and thermal properties of the crystalline drug. PMID:26568134

  13. Tools for Early Prediction of Drug Loading in Lipid-Based Formulations.

    PubMed

    Alskär, Linda C; Porter, Christopher J H; Bergström, Christel A S

    2016-01-04

    Identification of the usefulness of lipid-based formulations (LBFs) for delivery of poorly water-soluble drugs is at date mainly experimentally based. In this work we used a diverse drug data set, and more than 2,000 solubility measurements to develop experimental and computational tools to predict the loading capacity of LBFs. Computational models were developed to enable in silico prediction of solubility, and hence drug loading capacity, in the LBFs. Drug solubility in mixed mono-, di-, triglycerides (Maisine 35-1 and Capmul MCM EP) correlated (R(2) 0.89) as well as the drug solubility in Carbitol and other ethoxylated excipients (PEG400, R(2) 0.85; Polysorbate 80, R(2) 0.90; Cremophor EL, R(2) 0.93). A melting point below 150 °C was observed to result in a reasonable solubility in the glycerides. The loading capacity in LBFs was accurately calculated from solubility data in single excipients (R(2) 0.91). In silico models, without the demand of experimentally determined solubility, also gave good predictions of the loading capacity in these complex formulations (R(2) 0.79). The framework established here gives a better understanding of drug solubility in single excipients and of LBF loading capacity. The large data set studied revealed that experimental screening efforts can be rationalized by solubility measurements in key excipients or from solid state information. For the first time it was shown that loading capacity in complex formulations can be accurately predicted using molecular information extracted from calculated descriptors and thermal properties of the crystalline drug.

  14. The influence of direct laser metal sintering implants on the early stages of osseointegration in diabetic mini-pigs

    PubMed Central

    Tan, Naiwen; Liu, Xiangwei; Cai, Yanhui; Zhang, Sijia; Jian, Bo; Zhou, Yuchao; Xu, Xiaoru; Ren, Shuai; Wei, Hongbo; Song, Yingliang

    2017-01-01

    Background High failure rates of oral implants have been reported in diabetic patients due to the disruption of osseointegration. The aim of this study was to investigate whether direct laser metal sintering (DLMS) could improve osseointegration in diabetic animal models. Methods Surface characterizations were carried out on two types of implants. Cell morphology and the osteogenic-related gene expression of MG63 cells were observed under conditions of DLMS and microarc oxidation (MAO). A diabetes model in mini-pigs was established by intravenous injection of streptozotocin (150 mg/kg), and a total of 36 implants were inserted into the mandibular region. Micro-computed tomography (micro-CT) and histologic evaluations were performed 3 and 6 months after implantation. Results The Ra (the average of the absolute height of all points) of MAO surface was 2.3±0.3 µm while the DLMS surface showed the Ra of 27.4±1.1 µm. The cells on DLMS implants spread out more podia than those on MAO implants through cell morphology analysis. Osteogenic-related gene expression was also dramatically increased in the DLMS group. Obvious improvement was observed in the micro-CT and Van Gieson staining analyses of DLMS implants compared with MAO at 3 months, although this difference disappeared by 6 months. DLMS implants showed a higher bone–implant contact percentage (33.2%±11.2%) at 3 months compared with MAO group (18.9%±7.3%) while similar results were showed at 6 months between DLMS group (42.8%±10.1%) and MAO group (38.3%±10.8%). Conclusion The three-dimensional environment of implant surfaces with highly porous and fully interconnected channel and pore