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1

Comminution of food by complete-denture wearers.  

PubMed

A method for quantifying the comminution of an artificial test food (Optosil) was evaluated with respect to its suitability for measurements of masticatory performance in complete-denture wearers. Reference was made to subjects with natural dentitions. The description of particle size distributions generated by complete-denture wearers by a Rosin-Rammler equation was subject to limitations, due to the presence of large proportions of almost-intact particles, which had hardly been damaged or broken during chewing. This finding might be explained by: (i) the relatively high fracture strength of Optosil as compared with natural foods; and (ii) the limitations of complete-denture wearers in exerting bite forces. The particle size distributions obtained after repeated measurements and described by linear interpolation of data points were reproducible. In comparison with young adults with natural dentitions, the denture-wearers needed approximately seven times more chewing strokes to achieve an equivalent reduction in particle size. PMID:1556296

Slagter, A P; Olthoff, L W; Steen, W H; Bosman, F

1992-02-01

2

Occurrence rate of oral Candida albicans in denture wearer patients  

Microsoft Academic Search

Purpose: The aim was to determine the fungi occurrence rate in the oral cavity of denture wearer patients in compari- son to those without dentures. Material and methods: The examinations were conducted in patients treated in two clinical departments of the Univer- sity Hospital. Demographic data and those connected with basic diseases were collected and the evaluation concerning dentition and

Daniluk T; Tokajuk G; Stokowska W; Fiedoruk K; Cylwik-Rokicka D

2006-01-01

3

Maximum bite force in elderly indigenous and non-indigenous denture wearers.  

PubMed

The aim of this study was to compare the measures of maximum bite force (MBF) in elderly edentulous indigenous (Mapuche) and non-indigenous individuals with new complete dentures at two different measuring times. A sample of 100 elderly subjects was divided into two groups: 50 indigenous and 50 non-indigenous, each including 25 females and 25 males. All individuals were totally edentulous, with new maxillary and mandibular removable complete dentures. Measurements were taken at the time of new prosthesis placement and after 1 month of use. Subjects were asked to perform with maximum effort three bites per side at maximum intercuspidation, with a rest time of 2 minutes in between. Statistics were analyzed with Student 's t-test. The MBF values were significantly higher in indigenous than non-indigenous subjects. Force after 1 month of wearing the new prosthesis was significantly higher than at the time of new prosthesis placement. No significant difference was found between sides. Elderly indigenous complete denture wearers had the greatest MBF values. Denture wearers were observed to undergo an adaptation process to the new prosthesis, with MBF increasing considerably after one month of use. PMID:25560689

Borie, Eduardo; Orsi, Iara A; Fuentes, Ramón; Beltrán, Víctor; Navarro, Pablo; Pareja, Felipe; Raimundo, Lariça B

2014-01-01

4

Decreasing of residual alveolar ridge height in complete denture wearers. A five year follow up study.  

PubMed

The resorption of the residual alveolar ridges is a chronic and continuous process of bone remodeling. The aim of this study was to analyse the rate of residual ridge resorption at different sites in the both jaws in complete denture wearers, through a five-year period of denture wearing. Residual ridge changes were measured on successive lateral cephalograms at 5 measurement points of the maxilla and the mandible. The first lateral radiograph was obtained at the delivery of complete dentures. The second lateral cephalogram was obtained after five years of denture wearing. Measurements were performed using a calibrated grid. The results of this study showed the existence of a significant alveolar ridge resorption at all five measurement points of the maxilla and the mandible. The observed variables, such as body mass index and the night time denture wearing had no significant influence on the rate of residual alveolar ridge resorption (p > 0.05). The duration of edentulousness had a significant influence on the rate of residual ridge resorption with significantly higher amounts of alveolar bone height decrease in those patients who had lost the last remaining teeth more recently. PMID:20977102

Kovaci?, Ivan; Celebi?, Asja; Zlatari?, Dubravka Knezovi?; Petricevi?, Nikola; Bukovi?, Dino; Bitanga, Petar; Mikeli?, Branimira; Tadin, Antonija; Mehuli?, Ketij; Ognjenovi?, Marina

2010-09-01

5

In vitro activities of natural products against oral Candida isolates from denture wearers  

PubMed Central

Background Candida-associated denture stomatitis is a frequent infectious disease. Treatment of this oral condition is difficult because failures and recurrences are common. The aim of this study was to test the in vitro antifungal activity of pure constituents of essentials oils. Methods Eight terpenic derivatives (carvacrol, farnesol, geraniol, linalool, menthol, menthone, terpinen-4-ol, and ?-terpineol), a phenylpropanoid (eugenol), a phenethyl alcohol (tyrosol) and fluconazole were evaluated against 38 Candida isolated from denture-wearers and 10 collection Candida strains by the CLSI M27-A3 broth microdilution method. Results Almost all the tested compounds showed antifungal activity with MIC ranges of 0.03-0.25% for eugenol and linalool, 0.03-0.12% for geraniol, 0.06-0.5% for menthol, ?-terpineol and terpinen-4-ol, 0.03-0.5% for carvacrol, and 0.06-4% for menthone. These compounds, with the exception of farnesol, menthone and tyrosol, showed important in vitro activities against the fluconazole-resistant and susceptible-dose dependent Candida isolates. Conclusions Carvacrol, eugenol, geraniol, linalool and terpinen-4-ol were very active in vitro against oral Candida isolates. Their fungistatic and fungicidal activities might convert them into promising alternatives for the topic treatment of oral candidiasis and denture stomatitis. PMID:22118215

2011-01-01

6

[Resin-bonded fixed partial dentures].  

PubMed

A resin-bonded fixed partial denture is a prosthetic construction which can replace I or several teeth in an occlusal system and which comprises a pontic element which is adhesively attached to 1 or more abutment teeth. To compensate for the limited shear strength of the adhesive layer, the Jixed partial denture is occlusally supported by the abutment(s). A direct resin-bonded fixed partial denture is made of composite, reinforced or not by a frame of flexible metal or fiber material. For an indirect resin-bonded fixed partial denture, a metal, fibre-reinforced composite or ceramic substructure is fabricated in a dental laboratory. The basic principle of a resin-bonded fixed partial denture is minimal invasiveness. However, a restoration in an abutment tooth requires a certain occlusal space which is realized by tooth preparation. Resistance preparations may be performed to improve the longevity of resin-bonded fixed partial dentures. Both financially and biologically, a resin-bonded bridge is a cost-effective prosthetic construction. The longevity is limited, but when the construction fails the negative consequences for the abutments are generally limited, which leaves open several types of other treatments. PMID:23495569

Kreulen, C M; Creugers, N H J

2013-02-01

7

Evaluation of the influence of blood glucose level on oral candidal colonization in complete denture wearers with Type-II Diabetes Mellitus: An in vivo Study  

PubMed Central

Background: Candidal colonization in complete denture wearers is a commonly encountered condition that worsens in the presence of untreated Diabetes Mellitus. The aim of this study was to evaluate the correlation between oral candidiasis in denture-bearing mucosa and elevated blood glucose levels in complete denture wearers and to evaluate the effect of oral hypoglycemic drug therapy in controlling oral candidal colonization in denture-bearing mucosa of complete denture wearers with Type II Diabetes Mellitus. Materials and Methods: This prospective observational study involved the participation of 15 complete denture wearers with Type II Diabetes Mellitus. The sample collection was made prior and after oral hypoglycaemic drug intervention, by swabbing the rugal surfaces of palatal mucosa, cultured and the density of the candidal colony formed was analyzed and interpreted as colony forming units (CFU) per mL. The candidal samples CFU and corresponding pre- and post-prandial blood glucose levels were estimated, analyzed and compared using Karl Pearson correlation analysis and paired t-test (? = 0.05). Results: The Karl Pearson correlation analysis showed that there was a positive correlation between the blood glucose levels (PPS and FBS) and the candidal colonization (CFU) (P < 0.05). The mean values of all the variables were analyzed using the paired t-test. There was significant reduction in the mean values of blood glucose levels (P < 0.001) and the mean values of the CFU (P < 0.001) following oral hypoglycemic drug therapy. Conclusion: Positive correlation was observed between oral candidiasis in complete denture-bearing mucosa and elevated blood glucose levels and oral hypoglycemic drug therapy has a positive effect in controlling oral candidal colonization in complete denture wearers with Type II Diabetes Mellitus. PMID:23878569

Ganapathy, Dhanraj Muthuveera; Joseph, Sajeesh; Ariga, Padma; Selvaraj, Anand

2013-01-01

8

Removable partial denture design: a photoelastic study.  

PubMed

Quantifiable frozen-stress photoelastic techniques were used to analyze stresses induced in mandibular models by a conventional free-end saddle removable partial denture. Four quasi-anatomical mandibular models were constructed for processing, together with their respective calibration specimens, through identical time/temperature stress-freezing cycles. After processing and slicing, an unloaded control model demonstrated some low-order fringes adjacent to the coronal third of the abutment tooth roots, but was otherwise stress free. A lower bilateral free-end saddle partial denture was constructed and fitted in turn to each of the remaining three models. Each denture/model combination was then loaded and processed through a stress-freezing cycle. After processing, 6-mm slices were cut from selected regions for analysis for the presence of stresses. Using a polariscope with circular polarized, monochromatic light, values for maximum shear stress were calculated at selected points in the slices taken from the three loaded models. Variations up to 28% of the mean were obtained for the three experimental models as compared with the consistent results for the material fringe values obtained from the calibration specimens. The study pointed out the problems involved in using photoelastic stress analysis on complicated anatomical models. The interpretation of the results from such studies should be approached with caution. PMID:6544800

Stewart, B L; Edwards, R O

1984-01-01

9

Denture Adhesives  

MedlinePLUS

... Multiple-Use Dental Dispenser Devices Dental Amalgam Denture Adhesives Background Zinc and Potential Risk Reports of Problems ... Wearers Reporting Problems to the FDA Background Denture adhesives are pastes, powders or adhesive pads that may ...

10

[Stress analysis of distal free-end removable partial denture].  

PubMed

The study of the force distribution in distal free-end removable partial denture is complicated by the great difference of biomechanical property between the supporting tissue of the distal free-end removable partial denture, abutment tooth and alveolar mucosa under the denture base. Finite element method (FEM) was used in this study to estimate the effect on the abutment tooth and alveolar mucosa under various load conditions. The model is composed of the second premolar, the first molar and the second molar in acrylic resin teeth with the first premolar serving as the abutment. The stress on the abutment tooth was found reduced by 15% on comparing the load condition 3 (222 newton vertical force on each denture acrylic tooth) with the load condition 2 (222 newton vertical force on the second premolar and the first molar), and it can be further reduced by 22% in comparison to load condition 4 (222 newton vertical force on each denture tooth but shared equally to two occlusal contact points per denture tooth). The maximum displacement of the alveolar mucosa was found adjacent to the load area, and the maximum vertical displacement of the alveolar mucosa at load condition 4 is only 0.015 mm greater than load condition 3. It is concluded that when the number of occlusal contacts in distal free-end removable partial denture is increased and evenly distributed, the load on the abutment tooth will be decreased, with only minor effect on the alveolar mucosa. PMID:2282568

Liau, Y S; Chen, P S

1990-12-01

11

Multiple Logistic Regression Analysis of Risk Factors Associated with Denture Plaque and Staining in Chinese Removable Denture Wearers over 40 Years Old in Xi’an – a Cross-Sectional Study  

PubMed Central

Background Removable dentures are subject to plaque and/or staining problems. Denture hygiene habits and risk factors differ among countries and regions. The aims of this study were to assess hygiene habits and denture plaque and staining risk factors in Chinese removable denture wearers aged >40 years in Xi’an through multiple logistic regression analysis (MLRA). Methods Questionnaires were administered to 222 patients whose removable dentures were examined clinically to assess wear status and levels of plaque and staining. Univariate analyses were performed to identify potential risk factors for denture plaque/staining. MLRA was performed to identify significant risk factors. Results Brushing (77.93%) was the most prevalent cleaning method in the present study. Only 16.4% of patients regularly used commercial cleansers. Most (81.08%) patients removed their dentures overnight. MLRA indicated that potential risk factors for denture plaque were the duration of denture use (reference, ?0.5 years; 2.1–5 years: OR?=?4.155, P?=?0.001; >5 years: OR?=?7.238, P<0.001) and cleaning method (reference, chemical cleanser; running water: OR?=?7.081, P?=?0.010; brushing: OR?=?3.567, P?=?0.005). Potential risk factors for denture staining were female gender (OR?=?0.377, P?=?0.013), smoking (OR?=?5.471, P?=?0.031), tea consumption (OR?=?3.957, P?=?0.002), denture scratching (OR?=?4.557, P?=?0.036), duration of denture use (reference, ?0.5 years; 2.1–5 years: OR?=?7.899, P?=?0.001; >5 years: OR?=?27.226, P<0.001), and cleaning method (reference, chemical cleanser; running water: OR?=?29.184, P<0.001; brushing: OR?=?4.236, P?=?0.007). Conclusion Denture hygiene habits need further improvement. An understanding of the risk factors for denture plaque and staining may provide the basis for preventive efforts. PMID:24498369

Chai, Zhiguo; Chen, Jihua; Zhang, Shaofeng

2014-01-01

12

The postantifungal effect and phospholipase production of oral Candida albicans from smokers, diabetics, asthmatics, denture wearers and healthy individuals following brief exposure to subtherapeutic concentrations of chlorhexidine gluconate.  

PubMed

Candida albicans is the major aetiological agent of oral candidosis and one of its important virulent factors is the production of extracellular phospholipases, which can be modulated by subtherapeutic concentrations of antifungal agents thus decreasing their pathogenicity. Hence, considering that chlorhexidine gluconate (CG) is a common antimicrobial mouthwash used in dentistry and that its concentration in the mouth reaches subtherapeutic levels during dosage intervals due to the diluent effect of saliva and cleansing effect of the oral musculature, the postantifungal effect (PAFE) and the phospholipase production of oral C. albicans following brief exposure to subtherapeutic concentrations of CG was studied. Fifty C. albicans planktonic oral isolates obtained from smokers, diabetics, asthmatics using steroid inhalers, partial denture wearers and healthy individuals were exposed to three subtherapeutic concentrations of CG (0.005%, 0.0025% and 0.00125%) for 1 h. Isolates unexposed to CG was the control group. Thereafter the antiseptic was removed and the PAFE and phospholipase production was determined by a turbidometric method and a plate assay using an egg yolk agar medium respectively. Mean PAFE (hours) of 50 oral isolates of C. albicans following 1-h exposure to 0.005%, 0.0025% and 0.00125% CG was 6.97, 1.85 and 0.62 respectively. The phospholipase production of these isolates was significantly suppressed with a percentage reduction of 21.68, 18.20 and 14.04% following exposure to 0.005%, 0.0025% and 0.00125% CG respectively. Brief exposure of C. albicans isolates to subtherapeutic concentrations of CG would wield an antifungal effect by suppressing growth and phospholipase production, thereby quelling its pathogenicity. PMID:24655219

Ellepola, Arjuna N B; Joseph, Bobby K; Khan, Z U

2014-09-01

13

Prediction of mandibular bone remodelling induced by fixed partial dentures  

Microsoft Academic Search

Fixed partial dentures (FPD) or dental bridges have been extensively utilised in prosthodontic restoration. Despite considerable clinical success to date, there has been limited fundamental understanding of the biomechanical consequences induced by FPD treatment. It is noted that FPD construction significantly alters the biological and mechanical environment in the supporting bone region. Thus, the surrounding bones will be engaged to

Clarice Field; Qing Li; Wei Li; Mark Thompson; Michael Swain

2010-01-01

14

Oral health-related quality of life in complete denture wearers depending on their socio-demographic background, prosthetic-related factors and clinical condition  

PubMed Central

Objectives: To investigate the differences in impact on oral health-related quality of life (OHRQoL) among complete denture wearers depending on their socio-demographic characteristics, prosthetic-related factors and oral status. Study Design: 51 patients aged 50-90 years treated, from 2005 to 2010, with at least one complete denture at the Department of Buccofacial Prostheses of the Complutense University (Madrid) were enrolled in this cross-sectional study. All of the participants answered the Oral Health Impact Profile (OHIP-14sp) questionnaire. The additive scoring method was used. The prevalence of impacts was calculated by using the occasional threshold (OHIP-14sp score?2). Socio-demographic and prosthetic-related variables were gathered. Patients underwent clinical examination to assess their oral condition. Descriptive probes and Chi-Square tests were run (p?0.05). Results: The predominant participants’ profile was that of a man with a mean age of 69 years wearing complete dentures in both the maxilla and the mandible. The prevalence of impact was 23.5%, showing an average score of 19±9.8. The most affected domains were “functional limitation” and “physical pain”, followed by “physical disability”. Minor impacts were recorded for the psychological and social subscales (“psychological discomfort”, “psychological disability”, “social disability” and “handicap”). The prosthesis’ location significantly influenced the overall patient satisfaction, the lower dentures being the less comfortable. Having a complete removable denture as antagonist significantly hampered the patient satisfaction. Patients without prosthetic stomatitis and those who need repairing or changing their prostheses, recorded significantly higher OHIP-14sp total scores. Conclusions: The use of conventional complete dentures brings negative impacts in the OHRQoL of elderly patients, mainly in case of lower prostheses that required reparation or substitution, with a removable total denture as antagonist. The prosthetic stomatitis in this study was always associated to other severe illness, which may have influenced the self-perceived discomfort with the prostheses, as those patients were daily medicated with painkillers. Key words:Oral Health Impact Profile (OHIP), oral health-related quality of life (OHRQoL), patient satisfaction, complete denture, elderly patients. PMID:23385509

Perea, Carmen; Suárez-García, María J.; Del Río, Jaime; Torres-Lagares, Daniel; Montero, Javier

2013-01-01

15

Biomechanical considerations on tooth-implant supported fixed partial dentures  

PubMed Central

This article discusses the connection of teeth to implants, in order to restore partial edentulism. The main problem arising from this connection is tooth intrusion, which can occur in up to 7.3% of the cases. The justification of this complication is being attempted through the perspective of biomechanics of the involved anatomical structures, that is, the periodontal ligament and the bone, as well as that of the teeth- and implant-supported fixed partial dentures. PMID:23255882

Calvani, Pasquale; Hirayama, Hiroshi

2012-01-01

16

Masticatory efficiency in complete denture wearers with reduced dental arches--a randomised cross-over study.  

PubMed

One obstacle to placing artificial posterior teeth in manufacturing complete dentures is a reduction of the space between the maxilla and the mandible. Occasionally, second molar placement is not performed, as it does not affect aesthetics, phonetics or comfort. The aim of this study was to compare the masticatory efficiency between patients wearing maxillary and mandibular complete dentures with reduced dental arches (without second molars) (WSM) and with full dental arches (FDA). Twenty subjects were divided into two groups and randomly received new complete dentures. Patients in Group 1 were given dentures WSM, and those in Group 2 were given dentures with FDA. After the post-placement visits, an initial masticatory efficiency test was performed with Optocal, an artificial test food. Fifteen days later, second molars were placed in Group 1 and removed from Group 2, and a new test was performed. Comminuted material was treated and sieved under vibration. The mean and standard deviation of masticatory efficiency with FDA were 10.4 and 8.1, respectively. In the tests WSM, the mean and standard deviation were 8.4 and 3.3, respectively. After removing the second molars in Group 2 and adding them in Group 1, the mean and standard deviation were 15.7 and 14.7 for Group 1 and 12.5 and 10.4 for Group 2, respectively. Within the limitations of this study, placing artificial teeth up to the first molars can be performed when needed without compromising masticatory efficiency. PMID:24779746

Iegami, C M; Barbosa, W F; Furuyama, R J; Lima, J R B; de Campos, T T; Minagi, S; Tamaki, R

2014-08-01

17

The relationship between facial morphology and the structure of the alveolar part of the mandible in edentulous complete denture wearers. A preliminary study.  

PubMed

Abstract Objective. Although the effect of involutional processes that occurs in the maxilla and mandible of edentulous subjects is obvious, the problem of factors definitely determining the direction of changes still remains unsolved. This study was aimed at determining the relationship between facial morphology and the structure of the alveolar part and the body of the mandible in edentulous complete denture wearers. Materials and methods. Twenty-five healthy edentulous Caucasian patients in the 70.5 ± 9 years of age group were examined. All patients underwent tele-X-ray examination with the presence of currently used dentures in the oral cavity. To assess morphological parameters of the facial skeleton, cephalograms were analyzed according to Ricketts and Mc Namara method. To assess the mandible morphology, the films were measured using the method of Tallgren. Results. The period of edentulism was found to be negatively correlated with the anterior segment of the body of the mandible within its symphysis. The parameter corresponding to the location of the first lower molar showed a directly proportional correlation with G'-Sn', G'-Me', Sn'-Me', N-Ans, N-Me, Ans-Me, Co-Gn and Co-Go. Positive correlations were found between the parameters describing contour of the alveolar part of the body of the mandible and mandibular symphysis and G'-Me', Sn'-Me', N-Me, Ans-Me describing the height of the occlusal vertical dimension. Conclusion. The study showed a directly proportional correlation between the vertical occlusal dimension of the lower face conditioned by prosthetic rehabilitation and the height of the alveolar part in the lateral regions of the mandible. PMID:25183253

Ku?, Joanna; Sierpi?ska, Teresa; Go??biewska, Maria

2015-01-01

18

[A systematic approach for removable partial denture design].  

PubMed

Patients' attitudes, medical, surgical and financial considerations lead to the use of a removable partial denture (RPD) as the chosen prosthetic restoration even in the "dental implant era". The aim of this article is to describe a systematic approach to RPD design, so the RPD will be a long-term solution that will not harm the remaining oral tissues. There is an unlimited RPD design options. Choosing the right one involves considering biochemical factors, aesthetics and patients' comfort. A systematic approach starts with a correct diagnosis of the remaining hard and soft tissues, followed by a careful planning of support, stability and retention in that order. Additional elements should be added only at a later stage. A systematic track starting with a preliminary design, surveying of the model and analyzing the preliminary design on that surveyed model. If needed, that track should be reversed until an acceptable design is found. Support should ideally be achieved by using metal rests on healthy tooth structure. Tooth supported RPD are the most convenient ones and have a very good long-term prognosis. Old restorations or caries might impose changes from the ideal supporting rests. When posterior teeth are missing or when the edentulous area is vast, tooth-tissue supported RPD are used. In these cases one should gain initial support from the teeth and an additional support from the soft tissues. A denture base that is similar to a full denture base that would have been prepared for a fully edentulous patient should achieve this. If the prognosis of the potential supporting teeth is poor, a tissue-tooth supported RPD is considered. In these cases, the denture base is the primary supporting element, and stress relieving clasp-assemblies such as the RPI/RPA should be considered. Stability is achieved primarily by metal contacts between teeth and the metal framework of the RPD. In fact, any embracing part of the clasp assembly and a correct denture base can contribute to the stability. The distal parts of the retentive clasps produce the active retention. Since these parts generate lateral forces on the abutment teeth, a reciprocating element should be used. True reciprocation can only be achieved if the reciprocating element touches the tooth before the retentive clasp. After designing support, stability and retention, other parts should be considered. When a distal extension RPD is considered, an indirect retainer should be incorporated into the framework in order to prevent upward rotational movement of the denture. The major connector converts forces from one side to the other. In the upper jaw, that part acts also as a supporting element in Kennedy class I and class II cases. In other cases, a minimal type of a major connector should be chosen. As for minor connectors, these should only be added if other parts--such as guiding planes--couldn't be used for the purpose of connecting functional elements to the major connector. In any case, a 5 mm distance between two adjacent minor connectors should be allowed in order to prevent food from being trapped in that space. A systematic approach starts with diagnosis of the remaining tissues and with finding the correct prosthetic solution with the patient. If a RPD is the chosen solution, start designing with analysis of support, followed by stability and only then, decide upon the necessary retentive elements. All other parts should be considered later. Such a systematic approach will ensure a long-term solution and a happy patient. PMID:12830496

Samet, N; Shohat, M

2003-04-01

19

Fixed partial dentures investigated by optical coherent tomography  

NASA Astrophysics Data System (ADS)

Fixed partial prostheses as integral ceramics, integral polymers, metal ceramics or metal polymers bridges, are mainly used in the frontal part of the dental arch (especially the integral bridges). They have to satisfy high stress requirements as well as esthetic. The masticatory stress may induce fractures of the bridges. These may be triggered by initial materials defects or by alterations of the technological process. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of en-face optical coherence tomography (OCT) in detection and analysis of possible fractures in several integral fixed partial dentures. The materials used were represented by several fixed partial prostheses, integral ceramics, integral polymers, metal ceramics and metal polymers bridges. In order to discover the defects, scanning was performed from incisal, vestibular, oral and cervical directions material defects such as fractures and pores were investigated using OCT. In conclusion, en-face OCT has proven as a valuable non invasive method to investigate fixed partial prostheses before their insertion in the oral cavity.

Sinescu, Cosmin; Negrutiu, Meda; Todea, Carmen; Hughes, Mike; Tudorache, Florin; Podoleanu, Adrian G.

2008-02-01

20

Resin-bonded, glass fiber-reinforced composite fixed partial dentures: A clinical study  

Microsoft Academic Search

Statement of problem. Resin-bonded, glass fiber-reinforced composite fixed partial dentures (FPDs) have been under development for some time. There is a lack of data regarding the clinical usefulness of such prostheses. Purpose. The clinical performance of 31 resin-bonded, glass fiber-reinforced composite fixed partial dentures was evaluated in a preliminary study. Material and methods. The prostheses were made to replace 1

Pekka K. Vallittu; Camilla Sevelius

2000-01-01

21

Removable partial denture supported by implants with prefabricated telescopic abutments - a case report.  

PubMed

Implants have been designed to rehabilitate edentulous patients with fixed prosthesis or implant supported overdentures. Implant-supported single crowns and fixed partial dentures have become successful treatment alternatives to removable and fixed partial dentures. However, it is common to have clinical situations which make it impossible to use conventional as well as implant supported fixed partial dentures. The implant supported removable partial dentures can be a treatment modality that offers the multitude of benefits of implant-based therapy-biologic, biomechanical, social, and psychological to such patients. The aim of this article is to present a case report describing the fabrication and advantages of removable partial denture supported by teeth and implants for a patient with long edentulous span. The patient was satisfied with his dentures in terms of function and aesthetics. Regular follow-up visits over a period of three years revealed that the periodontal condition of remaining natural dentition and peri-implant conditions were stable. There was no evidence of excessive residual ridge resorption or mobility of the teeth, nor were any visible changes in the bone levels of the natural teeth or implants noted on radiographs. PMID:25121066

Kumar, Lalit; Sehgal, Komal

2014-06-01

22

A method for fabrication of implant-supported fixed partial dentures.  

PubMed

When restoring a partially edentulous arch with an implant-supported fixed partial denture, the optimal fit and function of the final restoration depend on the fabrication of an accurate impression and the registration of the interocclusal relationship. The present case report presents a method for the fabrication of impressions and the registration of the interocclusal relationship for implant-supported partial dentures. The described method allows the accurate transfer of the implant position and the registration of the interocclusal relationship using transfer key and electroformed gold copings. The key and copings were used to transfer the intraoral implant position to the cast, to position the abutments intraorally, and to facilitate the fabrication of the final partial denture. PMID:24914913

Zafiropoulos, Gregory-George; Hoffmann, Oliver; Deli, Georgio

2014-06-01

23

Prosthetic Rehabilitation of Hypophosphatasia with Precision Attachment Retained Unconventional Partial Denture: A Case Report  

PubMed Central

Deficiency of the alkaline phosphatase isoenzyme can lead to a rare hereditary disorder called Hypophosphatasia. It is characterized by defective mineralization of the skeletal and dental structures of the body. Hypophophatasia is classified into six clinical forms namely, perinatal lethal, perinatal benign, infantile, childhood, adult and odontohypophosphatasia. This clinical report describes the prosthetic rehabilitation of an 18-year-old girl with Hypophosphatasia with partial anodontia and no occlusion. A precision attachment retained unconventional removable partial denture in the maxillary arch and conventional removable partial denture in the mandibular were fabricated to establish an acceptable masticatory function, speech, occlusion and aesthetics for the patient. PMID:25654044

Nadiger, Ramesh Khandurao; Guttal, Satyabodh Shesharaj; Shetty, Omkar

2014-01-01

24

Adaptation of all-ceramic fixed partial dentures  

PubMed Central

Objectives To measure the marginal and internal fit of three-unit fixed partial dentures (FPDs) using the micro-CT technique, testing the null hypothesis that there is no difference in the adaptation between the ceramic systems studied. Methods Stainless steel models of prepared abutments were fabricated to design the FPDs. Ten FPDs were produced from each framework ceramic (YZ - Vita In-Ceram YZ and IZ - Vita In-Ceram Zirconia) using CEREC inLab according to the manufacturer instructions. All FPDs were veneered using the recommended porcelain. Each FPD was seated on the original model and scanned using micro-CT. Files were processed using NRecon and CTAn software. Adobe Photoshop and Image J software were used to analyze the cross-sections images. Five measuring locations were used as follows: MG – marginal gap; CA - chamfer area; AW - axial wall; AOT - axio-occlusal transition area; OA - occlusal area. The horizontal marginal discrepancy (HMD) was evaluated in another set of images. Results were statistically analyzed using ANOVA and Tukey tests (?=0.05). Results The mean values for MG, CA, AW, OA and HMD were significantly different for all tested groups (p<0.05). IZ exhibited greater mean values than YZ for all measuring locations except for AW and AOT. OA showed the greatest mean gap values for both ceramic systems. MG and AW mean gap values were low for both systems. Significance The ceramic systems evaluated showed different levels of marginal and internal fit, rejecting the study hypothesis. Yet, both ceramic systems showed clinically acceptable marginal and internal fit. PMID:21920595

Borba, Márcia; Cesar, Paulo F.; Griggs, Jason A.; Della Bona, Álvaro

2011-01-01

25

Marginal Integrity of CAD/CAM Fixed Partial Dentures  

PubMed Central

Objectives Computer-aided design (CAD) and manufacturing (CAM) allows the milling of high strength zirconia fixed partial dentures (FPD), however bonding to an inert ZrO2 ceramic surface may effect the marginal integrity of the FPDs. The aim of this investigation was to evaluate the marginal adaptation of zirconia FPDs at the interfaces between zirconia, cement, and tooth. Methods 32 3-unit FPDs were fabricated of the CAD/CAM Y-TZP zirconia (Lava, 3M Espe, Germany) according to the manufacturers’ instructions. Resin cements with corresponding primer and bonding systems were used to lute the FPDs: Compolute/EBS multi (3M Espe, Germany), Panavia F/ED (Kuraray, Japan), Variolink 2/Syntac classic (Ivoclar-Vivadent, FL) and RelyX Unicem/without treatment (3M Espe, Germany). Aualloy FPDs (BioPontostar, Bego, Germany) were cemented with RelyX Unicem and Harvard (Harvard, Germany) as the control. Marginal adaptation was evaluated with scanning electron microscopy using replica specimen before and after artificial aging. After aging, microleakage tests were performed with fuchsine solution. The interfaces between cement-tooth and cement-FPD were examined. Results At the interfaces (cement-tooth and cement-FPD), the systems showed a 95% or higher perfect margin before and after aging. Only Variolink2/Syntac had a marginal adaptation, lower than a 70% perfect margin. Generally, the fuchsine penetration was below 20%, only BioPontstar/Harvard andLava/Variolink2 showed penetration results between 80% and 100%. Conclusion The success of the adhesive cementation of zirconia FPDs depends on the cement system. Under the conditions of this study, zirconia FPDs showed good to sufficient marginal integrity in combination with Panavia/ED, Compolute/EBS and RelyX Unicem. PMID:19212494

Rosentritt, Martin; Behr, Michael; Kolbeck, Carola; Handel, Gerhard

2007-01-01

26

Relevance of Variations in the Opposing Dentition for the Functionality of Fixed and Removable Partial Dentures: A Systematic Review  

PubMed Central

The aim of this systematic review was to evaluate the functionality of fixed and removable partial dentures as test interventions in relation to variations in the opposing dentition and their prosthetic restoration. The abstracts identified in the respective databases were screened independently by two investigators. RCTs and uncontrolled studies were considered, provided the patients were included consecutively and the confounding variables were adequately monitored. Seventeen papers were included. The study and publication quality was assessed using a “biometric quality” tool showing an overall poor quality. The reported outcomes, such as survival rates, were in each case obtained from a single study. Two possible trends could be deduced for the endpoint longevity: (a) the first trend in favor of removable partial dentures, compared to fixed partial dentures, with a fully edentulous opposing arch fitted with a removable prosthesis; (b) the second trend in favor of implant-supported partial dentures, compared to conventionally fixed partial dentures, with natural opposing dentition or with a removable partial denture in the opposing arch. No evidence could be generated as to whether, and if so how, variations in the opposing dentition have a bearing on the decision to fit a partially edentulous arch with a fixed or removable partial denture. PMID:23193407

Pommer, Bernhard; Krainhöfner, Martin; Watzek, Georg; Tepper, Gabor; Dintsios, Charalabos-Markos

2012-01-01

27

Thermal cycling distortion of porcelain fused to metal fixed partial dentures  

Microsoft Academic Search

Statement of problem. The initial fit of porcelain fused to metal restorations deteriorates during the firing cycle of porcelain. Purpose. This study evaluated thermal cycling distortion of 3-unit porcelain fused to metal frameworks at different firing stages. Material and methods. A master model was designed to represent the 2 abutments of a 3-unit fixed partial denture replacing a missing mandibular

Deniz Gemalmaz; Semih Berksun; Hasan Necdet Alkumru; Cigdem Kasapoglu

1998-01-01

28

Viscoelastic finite element analysis of an all-ceramic fixed partial denture  

Microsoft Academic Search

In recent years metal-free ceramic systems have become increasingly popular in dental practice because of their superior aesthetics, chemical durability and biocompatibility. Recently, manufacturers have proposed new dental ceramic systems that are advertized as being suitable for posterior fixed partial dentures (FPDs). Reports indicate that some of these systems have exhibited poor clinical performance. The objective of this study was

Paul H. DeHoff; Kenneth J. Anusavice; Nils Götzen

2006-01-01

29

Two-dimensional photoelastic simulation of a castable ceramic fixed partial denture.  

PubMed

Two-dimensional photoelastic models were used to determine the optimum design and loading conditions for a three-unit castable ceramic fixed partial denture. Findings relating to design and material variables can be summarized as follows. 1. Higher modulus cements impart more rigidity to the fixed partial denture design and result in lower stresses. 2. A short connector results in higher stress than a long connector; however, the length of the connector should not exceed one half the mesial-to-distal length of the pontic. 3. An intermediate thickness of cement results in the best stress distribution. 4. The male connector is best attached to the bulkier abutment. 5. Occlusal cement eccentricity is less desirable than cervical eccentricity. 6. The most undesirable loading site is directly above the connector. PMID:3276881

Farah, J W; Craig, R G; Eden, G T; Grossman, D G

1988-01-01

30

Failure of All-ceramic Fixed Partial Dentures in vitro and in vivo: Analysis and Modeling  

Microsoft Academic Search

Hertzian cone cracks visible at the loading site of 20 all-ceramic fixed partial dentures (FPDs), tested in vitro, led to the hypotheses that failure was due to the propagation of localized contact damage crack systems (Hertzian stress state) and that such damage was an unlikely clinical failure mode. Fractographic analysis of the 20 laboratory-failed and nine clinically-failed all-ceramic FPDs allowed

J. R. Kelly; J. A. Tesk; J. A. Sorensen

1995-01-01

31

Cyclic mechanical pressure-loading alters epithelial homeostasis in a three-dimensional in vitro oral mucosa model: clinical implications for denture-wearers.  

PubMed

Denture-wearing affects the quality and quantity of epithelial cells in the underlying healthy oral mucosa. The physiologic mechanisms, however, are poorly understood. This study aimed to compare histologic changes and cellular responses of an epithelial cell layer to cyclic mechanical pressure-loading mimicking denture-wearing using an organotypic culture system to develop a three-dimensional in vitro oral mucosa model (3DOMM). Primary human oral keratinocytes and fibroblasts were serially grown in a monolayer culture, and cell viability was measured under continuous cyclic mechanical pressure (50 kPa) for 7 days (cycles of 60 min on, 20 s off to degas and inject air). Upon initiation of an air-liquid interface culture for epithelial stratification, the cyclic pressure, set to the mode above mentioned, was applied to the 3DOMMs for 7 days. Paraffin-embedded 3DOMMs were examined histologically and immunohistochemically. In the monolayer culture, the pressure did not affect the viability of oral keratinocytes or fibroblasts. Few histologic changes were observed in the epithelial layer of the control and pressure-loaded 3DOMMs. Immunohistochemical examination, however, revealed a significant decrease in Ki-67 labelling and an increase in filaggrin and involucrin expression in the suprabasal layer of the pressure-loaded 3DOMMs. Pressure-loading attenuated integrin ?1 expression and increased matrix metalloproteinase-9 activity. Incomplete deposition of laminin and type IV collagen beneath the basal cells was observed only in the pressure-loaded 3DOMM. Cyclic pressure-loading appeared to disrupt multiple functions of the basal cells in the 3DOMM, resulting in a predisposition towards terminal differentiation. Thus, denture-wearing could compromise oral epithelial homeostasis. PMID:25472623

Shiomi, A; Izumi, K; Uenoyama, A; Saito, T; Saito, N; Ohnuki, H; Kato, H; Kanatani, M; Nomura, S; Egusa, H; Maeda, T

2015-03-01

32

Epidemiology and etiology of denture stomatitis.  

PubMed

Denture stomatitis, a common disorder affecting denture wearers, is characterized as inflammation and erythema of the oral mucosal areas covered by the denture. Despite its commonality, the etiology of denture stomatitis is not completely understood. A search of the literature was conducted in the PubMed electronic database (through November 2009) to identify relevant articles for inclusion in a review updating information on the epidemiology and etiology of denture stomatitis and the potential role of denture materials in this disorder. Epidemiological studies report prevalence of denture stomatitis among denture wearers to range from 15% to over 70%. Studies have been conducted among various population samples, and this appears to influence prevalence rates. In general, where reported, incidence of denture stomatitis is higher among elderly denture users and among women. Etiological factors include poor denture hygiene, continual and nighttime wearing of removable dentures, accumulation of denture plaque, and bacterial and yeast contamination of denture surface. In addition, poor-fitting dentures can increase mucosal trauma. All of these factors appear to increase the ability of Candida albicans to colonize both the denture and oral mucosal surfaces, where it acts as an opportunistic pathogen. Antifungal treatment can eradicate C. albicans contamination and relieve stomatitis symptoms, but unless dentures are decontaminated and their cleanliness maintained, stomatitis will recur when antifungal therapy is discontinued. New developments related to denture materials are focusing on means to reduce development of adherent biofilms. These may have value in reducing bacterial and yeast colonization, and could lead to reductions in denture stomatitis with appropriate denture hygiene. PMID:21463383

Gendreau, Linda; Loewy, Zvi G

2011-06-01

33

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

PubMed Central

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 (?Strain). 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 ?Strain values of the different loading conditions. Results. During unilateral and bilateral loading the maximum ?Strain was predominantly observed in a buccal direction. As the load was moved anteriorly the ?Strain 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

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

2013-01-01

34

Effect of framework design on fracture resistance of zirconium oxide posterior fixed partial dentures  

PubMed Central

Introduction: The effect of framework design modifications in all-ceramic systems is not fully understood. The aim of this investigation was to evaluate the effect of different framework designs on fracture resistance of zirconium oxide posterior fixed partial dentures (FPD). Materials and Methods: Thirty two posterior zirconia FPD cores were manufactured to replace a second premolar. The specimens were divided into four groups; I: 3 × 3 connector and standard design, II: 3 × 3 connector and modified design, III: 4 × 4 connector dimension, and standard design and IV: 4 × 4 connector dimension and modified design. After storing for one week in artificial saliva and thermocycling (2000 cycles, 5-55°C), the specimens were loaded in a universal testing machine at a constant cross-head speed of 0.5 mm/min until failure occurred. The Weibull, Kruskal-Wallis, and Mann-Whitney tests were used for statistical analysis (? = 0.05). Results: The mean fracture resistance of groups with 4 × 4 mm connector was significantly higher than groups with 3 × 3 mm connector (P < 0.001). Although, the fracture resistance of the modified frameworks was increased in the present study (1.1 times), they were not significantly different from anatomic specimens (P = 0.327). Conclusions: The fracture resistance of the zirconia posterior-fixed partial dentures was significantly affected by the connector size; it was not affected by the framework modification. PMID:23559956

Salimi, Hadi; Mosharraf, Ramin; Savabi, Omid

2012-01-01

35

Theoretical role of adjunctive implant positional support in stress distribution of distal-extension mandibular removable partial dentures.  

PubMed

This preliminary study evaluated the adjunctive supporting role of diverse implant positions on stress distribution in a Class I removable partial denture (RPD) design. Nine three-dimensional finite element models were prepared to simulate mandibular RPD designs with three different loading conditions applied. Implant supported designs demonstrated lower stress value concentrations and mucosal displacement. PMID:25390876

Xiao, Wei; Li, Zhiyong; Shen, Shiqian; Chen, Shaowu; Wang, Yining; Wang, Jiawei

2014-01-01

36

Fracture resistance of inlay-retained fixed partial dentures reinforced with fiber-reinforced composite.  

PubMed

In this study, the effect on the fracture load of inlay-retained composite fixed partial dentures (FPDs) caused by reinforcing them with fiber-reinforced composite (FRC) in different positions was examined. Experimental FPDs were fabricated using Estenia/EG Fiber (Kuraray Medical). Pontic reinforcement was then performed in one of the following three ways: reinforced the central area in a single line or in double straight lines, or reinforced the bottom in a curved line. The finding was that, when the area ranging from the connector to the bottom of the pontic was reinforced with FRC in a curved line, the fracture load of the FPDs tended to become higher. In addition, the FPDs fractured mainly at the veneering composite of the connector area. Based on the results of this study, it was concluded that reinforcement using FRC is effective, and that the veneering composite in the connector area needs to have sufficient strength to prevent the fractures. PMID:16706289

Waki, Tomonori; Nakamura, Takashi; Nakamura, Toshio; Kinuta, Soichiro; Wakabayashi, Kazumichi; Yatani, Hirofumi

2006-03-01

37

Aesthetic Rehabilitation of Oligodontia in Primary Dentition with Adhesive Partial Denture  

PubMed Central

The primary teeth are essential for bone development and establishment of the arches on occlusion. Thus, the congenitally absence of teeth may trigger a shift in the balance of the occlusion, promoting disharmony in the structures of the maxilla-mandibular system. However, some interventions are possible to be performed in these cases even in pediatric patients, to redirect growth, preventing growth deviations and reestablishing the aesthetic. The aim of this paper is to report the treatment of a 4-year-old child presenting congenitally absence of mandibular central and lateral incisors and maxilla lateral incisors, which consequently compromises aesthetics, occlusal function, and the development and the functional growth of the bones. The oral rehabilitation was performed with an adhesive partial denture, which was able to restore the aesthetic and the occlusal function, therefore being a viable alternative in the treatment of this patient of little age. PMID:24319602

Correia, Marília Ferreira; Nogueira, Marianne Nicole; Bedran, Telma Blanca; Palomari Spolidorio, Denise Madalena

2013-01-01

38

Biomechanical Response in Mandibular Bone due to Mastication Loading on 3-Unit Fixed Partial Dentures  

PubMed Central

An understanding of functional responses in oral bone is a crucial component of dental biomechanics. The purpose of this study was to investigate the potential biological remodelling response during mastication on the mandibular pre- and post-insertion of a fixed partial denture (FPD). A series of three-dimensional (3D) finite element analysis (FEA) models were presented pre- and postextraction to determine the biomechanical responses to masticatory loading in the anterior mandible. Equivalent strains were analysed at lingual/buccal and mesial/distal areas of the premolar to molar region and quantified to anticipate bone remodelling response. Mandibular bone incorporating an FPD experienced substantially greater stress/strain magnitudes than that prior to placement of fixed prosthodontics, which is suggestive of engagements of bone remodelling. The results suggest similar outcomes to those reported clinically. Developing a simulation reflecting the outcomes of restorative treatment can provide meaningful insight into restorative treatment planning, clinical outcomes, and fixed prosthodontics designs. PMID:20981154

Field, Clarice; Li, Qing; Li, Wei; Swain, Michael

2010-01-01

39

Single Tooth Replacement Using InCeram Resin Bonded Fixed Partial Denture: A Clinical Report  

PubMed Central

This clinical report describes a treatment option for replacement of a missing mandibular anterior tooth using InCeram resin bonded fixed partial denture (RBFPD). The conventional approach for replacing mandibular incisors dictates the placement of either a conventional porcelain-fused-to-metal (PFM) bridge, Maryland bridge, or fiber-reinforced composite veneer bridge and several appearance-related disadvantages have been reported in the use of a prosthesis that incorporates a metal substructure. The InCeram bridge is a minimally invasive restoration and eliminates undesirable incisal graying frequently observed in metal RBFPDs. This method was successfully clinically applied to overcome shortcomings of other approaches that may require a minimal invasive technique to preserve lasting sound tooth structure. PMID:24910683

Moslehifard, Elnaz; Farid, Farzaneh

2014-01-01

40

Influence of implant inclination associated with mandibular class I removable partial denture.  

PubMed

The aim of this study was to use two-dimensional finite element method to evaluate the displacement and stress distribution transmitted by a distal extension removable partial denture (DERPD) associated with an implant placed at different inclinations (0, 5, 15, and 30 degrees) in the second molar region of the edentulous mandible ridge. Six hemimandibular models were created: model A, only with the presence of the natural tooth 33; model B, similar to model A, with the presence of a conventional DERPD replacing the missing teeth; model C, similar to the previous model, with a straight implant (0 degrees) in the distal region of the ridge, under the denture base; model D, similar to model C, with the implant angled at 5 degrees in the mesial direction; model E, similar to model C, with the implant angled at 15 degrees in the mesial direction; and model F, similar to ME, with the implant angled at 30 degrees in the mesial direction. The models were created with the use of the AutoCAD 2000 program (Autodesk, Inc, San Rafael, CA) and processed for finite element analysis by the ANSYS 8.0 program (Swanson Analysis Systems, Houston, PA). The force applied was vertical of 50 N on each cusp tip. The results showed that the introduction of the RPD overloaded the supporting structures of the RPD and that the introduction of the implant helped to relieve the stresses of the mucosa alveolar, cortical bone, and trabecular bone. The best stress distribution occurred in model D with the implant angled at 5 degrees. The use of an implant as a support decreased the displacement of alveolar mucosa for all inclinations simulated. The stress distribution transmitted by the DERPD to the supporting structures was improved by the use of straight or slightly inclined implants. According to the displacement analysis and von Mises stress, it could be expected that straight or slightly inclined implants do not represent biomechanical risks to use. PMID:21415633

de Freitas Santos, Ciandrus Moraes; Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; de Moraes, Sandra Lúcia Dantas; Falcón-Antenucci, Rosse Mary

2011-03-01

41

Veneering technique for a Ti-6Al-7Nb framework used in a resin-bonded fixed partial denture with a highly filled indirect composite.  

PubMed

This article presents a veneering technique for fixed partial denture frameworks made from a Ti-6Al-7Nb alloy. The fixed partial denture framework was prepared with a magnesia-based mold material and a centrifugal casting machine. An esthetic veneer was fabricated with a highly filled dual-polymerized composite material and a metal-conditioning agent. This technique can be applied as a standardized veneering procedure for the titanium alloy, for which porcelain fusing is currently difficult. PMID:12488858

Matsumura, Hideo; Yoneyama, Takayuki; Shimoe, Saiji

2002-12-01

42

Titanium alloy removable partial denture framework in a patient with a metal allergy: a case study.  

PubMed

This article describes a mandibular bilateral free-end saddle case in a 63-year-old female with a metal allergy. Conventional denture alloys are contraindicated and acrylic mucosa-borne dentures were not tolerated. The use of a titanium alloy framework is shown to be a successful alternative in this case. PMID:22878308

Oluwajana, F; Walmsley, A D

2012-08-01

43

Predoctoral prosthodontic curricula on removable partial dentures: survey of Turkish dental schools.  

PubMed

This study was conducted to evaluate the predoctoral removable partial denture (RPD) curricula in Turkish dental schools in regards to materials, techniques, and approaches. A questionnaire consisting of eighteen multiple-choice questions was sent by e-mail to the senior members of the prosthodontic departments of seventeen long-established dental schools in Turkey. The response rate was 100 percent. All schools (100 percent) used custom trays for making final impressions of partially dentate arches, taught border molding of the custom tray for the edentulous areas, used modeling plastic impression compound in border molding the final impression trays, and used base metal alloys for RPD frameworks. None of the schools had an in-house laboratory that fabricates RPD frameworks, and none of the students cast the frameworks of their own RPDs. The majority of schools used irreversible hydrocolloid as a final impression (70.6 percent) and dental surveyor (76.5 percent) in the designing of RPDs. The majority of schools did not flask their own RPDs (64.7 percent), did not treat patients using RPDs with attachments (76.5 percent), and did not perform the altered cast technique in bilateral and unilateral distal extension RPD cases (76.5 percent). Six teen schools (94.1 percent) had a minimum number of RPD arches that a student must complete in order to graduate. It was found that predoctoral RPD curricula in Turkish dental schools were both variable and similar. PMID:23314471

Dikbas, Idil; Ozkurt, Zeynep; Kazazoglu, Ender

2013-01-01

44

Short-term retrospective case series of implant-assisted removable partial dentures with locator abutments.  

PubMed

The purpose of this retrospective case series was to report on the clinical performance of implant-assisted removable partial dentures (IARPDs) with Locator abutments in different partial edentulism situations, with a mean follow-up period of 28.6 months. Twelve consecutive patients were treated with IARPDs. A total of 24 implants were placed in the edentulous area. Minimum follow-up period was 12 months. Overall patient satisfaction, health of peri-implant tissues, survival of implants and abutments, and prosthetic complications were reported. Overall implant survival was 91.6%; two implants failed. No major complications were reported-only one IARPD metal framework broke. No Locator abutment loosening was reported. Within the limitations of this retrospective study, treatment with IARPDs can improve the patient's function, phonetics, and esthetics without the need for extensive bone regeneration surgeries and prosthodontic rehabilitations. However, well-designed prospective clinical studies on IARPDs are needed to support their long-term use. PMID:25411746

Ortiz-Puigpelat, Octavi; Gargallo-Albiol, Jordi; Hernández-Alfaro, Federico; Cabratosa-Termes, Josep

2014-01-01

45

Comparative evaluation of retentive properties of acid etched resin bonded fixed partial dentures  

PubMed Central

Background Little consensus exist in suitable tooth preparation design and alloy pre-treatment methods for improving the retention of resin bonded fixed partial dentures (RBFPDs). Methods An in-vitro experiment was done with four designs. Group A: standard form, B: wings and proximal slices, C: wings, proximal slice and grooves, D: wings, proximal slice, grooves and occlusal coverage. Alloys were subjected to pre-treatment procedures like Group I: control, II: sand blasting, III: electro etching, IV: tin plating. Debonding forces of the castings were recorded in a universal testing machine and results were analyzed by student's ‘t’ test. Results Group B, C and D showed higher debonding forces compared to A. However, there were no significant differences in mean force values among Groups B, C and D. Group II, III and IV with different alloy pre-treatment methods demonstrated higher values against control. Inter group variations among Group II, III and IV were not significant. Conclusion Tooth preparation with adequate surface extensions and pre-treatment procedures of casting alloys are two parameters that play important role in determining the retentive features of RBFPDs. Different types of tooth preparation designs and alloy pre-treatment methods exert almost similar influence in increasing the retention of acid etched RBFPDs. PMID:24623948

Arora, Vimal; Sharma, M.C.; Dwivedi, Ravi

2013-01-01

46

Fracture resistance of fixed partial dentures supported by different abutment combinations: an ex vivo study.  

PubMed

This study sought to compare the fracture resistance of and categorize failure modes exhibited by fixed partial dentures (FPDs) supported by natural teeth, implants, or mixed tooth-implant abutments. Three groups utilized three different abutment combinations: all natural teeth, all implants, and a mixture of teeth and implants. The teeth were prepared and zero-angled titanium abutments were installed over the implants. Standardized conventional three-unit porcelain-fused-to-metal FPDs were fabricated, following the conventional ceramic build-up technique. The inner surfaces of the bridges were air-abraded (50 ?m Aluminum Oxide at 80 psi), cleaned in an ultrasonic bath for 10 minutes, and cemented over abutments using glass ionomer cement. The FPDs were fixed in a universal testing machine and compressed to fracture using a three-unit metal block at a 5 mm/minute crosshead speed. Fracture loads ranged from 460 to 5,700 N. Bridges supported by either implant abutments only or mixed implant-tooth abutments showed higher fracture loads (2,940 and 3,390 N, respectively) than those supported entirely by natural teeth (1,386 N) (p < 0.05). However, fracture of the veneering porcelain was common among all types of abutments. PMID:23032236

Al-Wahadni, Ahed; Al-Saleh, Hussain; Al-Quran, Firas; Hatamleh, Muhanad M

2012-01-01

47

Finite element analysis of a four-unit all-ceramic fixed partial denture.  

PubMed

All-ceramic restorations are known to be prone to brittle fracture. However, a previously performed in vitro study indicates that four-unit fixed partial dentures (FPDs) with a zirconia framework are sufficiently strong to withstand occlusal forces in the posterior region. The aim of this study was to determine the stress distribution in such a four-unit FPD made of yttria-stabilized polycrystalline tetragonal zirconia (Y-TZP), under an occlusal load. A three-dimensional finite element model was constructed and a stress analysis performed with a force of 1630 N applied at the centre of the middle connector area. The location of maximum tensile stress according to finite element analysis coincided with the fracture origin of all 10 specimens fractured within the previous in vitro study. The maximum tensile stress in the area of the middle connector amounted to 633 MPa. It increased with the load being applied from the oral towards the buccal side (648 MPa) and decreased with the load being applied from the buccal towards the oral side (570 MPa). These stresses are of the same order as the flexural strength of Y-TZP, determined under standardized test conditions to be 600-1000 MPa. The model presented is intended to be used for further investigations, including thermally induced stresses during veneering. PMID:19117821

Dittmer, Marc Philipp; Kohorst, Philipp; Borchers, Lothar; Stiesch-Scholz, Meike

2009-05-01

48

Reassessing the presence of Candida albicans in denture-related stomatitis  

Microsoft Academic Search

Objective. The aim of this study was to reevaluate the link between Candida albicans and denture-related stomatitis according to a modified Newton classification, which reflects the classic types of inflammation as well as the extent to which the tissue is affected. Study design. Two groups of denture wearers were evaluated for denture-related stomatitis. The presence and number of yeasts on

Jean Barbeau; Jacynthe Séguin; Jean Paul Goulet; Louis de Koninck; Sylvie Louise Avon; Benoit Lalonde; Pierre Rompré; Noëlla Deslauriers

2003-01-01

49

A critically appraised topic review of computer-aided design/computer-aided machining of removable partial denture frameworks.  

PubMed

A critically appraised topic (CAT) review is presented about the use of computer-aided design (CAD)/computer-aided machining (CAM) removable partial denture (RPD) frameworks. A systematic search of the literature supporting CAD/CAM RPD systems revealed no randomized clinical trials, hence the CAT review was performed. A PubMed search yielded 9 articles meeting the inclusion criteria. Each article was characterized by study design and level of evidence. No clinical outcomes research has been published on the use of CAD/CAM RPDs. Low levels of evidence were found in the available literature. Clinical research studies are needed to determine the efficacy of this treatment modality. PMID:24286656

Lang, Lisa A; Tulunoglu, Ibrahim

2014-01-01

50

Comparative Evaluation of Marginal Accuracy of a Cast Fixed Partial Denture Compared to Soldered Fixed Partial Denture Made of Two Different Base Metal Alloys and Casting Techniques: An In vitro Study.  

PubMed

The periodontal health of abutment teeth and the durability of fixed partial denture depends on the marginal adaptation of the prosthesis. Any discrepancy in the marginal area leads to dissolution of luting agent and plaque accumulation. This study was done with the aim of evaluating the accuracy of marginal fit of four unit crown and bridge made up of Ni-Cr and Cr-Co alloys under induction and centrifugal casting. They were compared to cast fixed partial denture (FPD) and soldered FPD. For the purpose of this study a metal model was fabricated. A total of 40 samples (4-unit crown and bridge) were prepared in which 20 Cr-Co samples and 20 Ni-Cr samples were fabricated. Within these 20 samples of each group 10 samples were prepared by induction casting technique and other 10 samples with centrifugal casting technique. The cast FPD samples obtained were seated on the model and the samples were then measured with travelling microscope having precision of 0.001 cm. Sectioning of samples was done between the two pontics and measurements were made, then the soldering was made with torch soldering unit. The marginal discrepancy of soldered samples was measured and all findings were statistically analysed. The results revealed minimal marginal discrepancy with Cr-Co samples when compared to Ni-Cr samples done under induction casting technique. When compared to cast FPD samples, the soldered group showed reduced marginal discrepancy. PMID:24605006

Jei, J Brintha; Mohan, Jayashree

2014-03-01

51

[Treatment of removable partial dentures. 2. Causes and consequences of a reduced occlusal system  

Microsoft Academic Search

The occlusal system is part of the orofacial system and consists of the maxillary and mandibular alveolar ridge and teeth which are occluding or not or the removable denture teeth. The most prevalent causes of loss of teeth are insufficient oral self care or inadequate professional oral healthcare service. A reduced dentition can be described in terms of diastemas in

D. J. Witter; J. C. Barel; C. de Baat; H. M. A. M. Keltjens; N. H. J. Creugers

2011-01-01

52

Photoelastic stress analysis of different designs of cement-retained fixed partial dentures on Morse taper oral implants.  

PubMed

There is no consensus in literature regarding the best plan for prosthetic rehabilitation with partial multiple adjacent implants to minimize stress generated in the bone-implant interface. The aim of this study was to evaluate the biomechanical behavior of cemented fixed partial dentures, splinted and nonsplinted, on Morse taper implants and with different types of coating material (ceramic and resin), using photoelastic stress analysis. A photoelastic model of an interposed edentulous space, missing a second premolar and a first molar, and rehabilitated with 4 different types of cemented crowns and supported by 2 adjacent implants was used. Groups were as follows: UC, splinted ceramic crowns; IC, nonsplinted ceramic crowns; UR, splinted resin crowns; and IR, nonsplinted resin crowns. Different vertical static loading conditions were performed: balanced occlusal load, 10 kgf; simultaneous punctiform load on the implanted premolar and molar, 10 kgf; and alternate punctiform load on the implanted premolar and molar, 5 kgf. Changes in stress distribution were analyzed in a polariscope, and digital photographs were taken of each condition to allow comparison of stress pattern distribution around the implants. Cementation of the fixed partial dentures generated stresses between implants. Splinted restorations distributed the stresses more evenly between the implants than nonsplinted when force was applied. Ceramic restorations presented better distribution of stresses than resin restorations. Based on the results obtained, it was concluded that splinted ceramic restorations promote better stress distribution around osseointegrated implants when compared with nonsplinted crowns; metal-ceramic restorations present less stress concentration and magnitude than metal-plastic restorations. PMID:21415635

Menani, Luiz Ricardo; Tiossi, Rodrigo; de Torres, Érica Miranda; Ribeiro, Ricardo Faria; de Almeida, Rossana Pereira

2011-03-01

53

International telephone code used for citizenship identification in a denture.  

PubMed

This case report describes a simple method for identifying the citizenship of a denture wearer by marking the telephone country code number inside the denture base. A wax pattern for the denture framework was prepared on the refractory cast. A piece of embossing tape, containing the country code (81, Japan), Japanese prefectural code, and abbreviation of the dental clinic where the denture was fabricated, was placed on the metal framework. A titanium-aluminum-niobium (Ti-6Al-7Nb) alloy was cast in the mold, and the denture was then fabricated by the conventional method. The casting satisfactorily reproduced the embossed letters, and the plate was identifiable through the gingiva-colored acrylic denture base resin. Since an embossed metal plate integrated with the skeleton is embedded in the denture base resin material, the current denture marking technique serves as a simple procedure for insertion of an undegradable denture identification mark which makes it possible to identify the nationality of the denture wearer. PMID:18195519

Matsumura, Hideo; Shimoe, Saiji; Nagano, Kiyoshi; Tanoue, Naomi

2007-12-01

54

Effects of mechanical properties of adhesive resin cements on stress distribution in fiber-reinforced composite adhesive fixed partial dentures.  

PubMed

Using finite element analysis (FEA), this study investigated the effects of the mechanical properties of adhesive resin cements on stress distributions in fiber-reinforced resin composite (FRC) adhesive fixed partial dentures (AFPDs). Two adhesive resin cements were compared: Super-Bond C&B and Panavia Fluoro Cement. The AFPD consisted of a pontic to replace a maxillary right lateral incisor and retainers on a maxillary central incisor and canine. FRC framework was made of isotropic, continuous, unidirectional E-glass fibers. Maximum principal stresses were calculated using finite element method (FEM). Test results revealed that differences in the mechanical properties of adhesive resin cements led to different stress distributions at the cement interfaces between AFPD and abutment teeth. Clinical implication of these findings suggested that the safety and longevity of an AFPD depended on choosing an adhesive resin cement with the appropriate mechanical properties. PMID:22447051

Yokoyama, Daiichiro; Shinya, Akikazu; Gomi, Harunori; Vallittu, Pekka K; Shinya, Akiyoshi

2012-01-01

55

Influence of Implant Position on Stress Distribution in Implant-Assisted Distal Extension Removable Partial Dentures: A 3D Finite Element Analysis  

PubMed Central

Objective: Distal extension removable partial denture is a prosthesis with lack of distal dental support with a 13-fold difference in resiliency between the mucosa and the periodontal ligament, resulting in leverage during compression forces. It may be potentially destructive to the abutments and the surrounding tissues. The aim of this study was to assess the effect of implant location on stress distribution, in distal extension implant assisted removable partial dentures. Materials and Methods: Three-dimensional models of a bilateral distal extension partially edentulous mandible containing anterior teeth and first premolar in both sides of the arch, a partial removable denture and an implant (4×10mm) were designed. With the aid of the finite element program ANSYS 8.0, the models were meshed and strictly vertical forces of 10 N were applied to each cusp tip. Displacement and von Mises Maps were plotted for visualization of results. Results: When an implant was placed in the second premolar region, the highest stress on implant, abutment tooth and cancellous bone was shown. The lowest stress was shown on implant and bone in the 1st molar area. Conclusion: Implants located in the first molar area showed the least distribution of stresses in the analyzed models. PMID:25628678

Memari, Yeganeh; Geramy, Allahyar; Fayaz, Amir; Rezvani Habib Abadi, Shirin; Mansouri, Yasaman

2014-01-01

56

Ageing exacerbates damage of systemic and salivary neutrophils from patients presenting Candida-related denture stomatitis  

Microsoft Academic Search

BACKGROUND: Ageing leads to a decline in the function of the immune system, increasing the body's susceptibility to infections through the impairment of T-cells, macrophages, neutrophils and dendritic cells Denture stomatitis is a primary oral disease affecting elderly denture wearers. The major etiologic factor involved in this pathology is the infection by Candida albicans, an opportunistic pathogen that causes local

Thaís Helena Gasparoto; Narciso Almeida Vieira; Vinicius Carvalho Porto; Ana Paula Campanelli; Vanessa Soares Lara

2009-01-01

57

Using CAD/CAM technology to create a 10-unit zirconia fixed partial denture--a UTHSCSA dental school case report.  

PubMed

From diagnosis and treatment planning to the materials being used, technology is changing dentistry. New materials are providing dentists greater options for treatment, while technology is streamlining the workflow in the office and dental laboratory. Traditionally the creation of a long-span fixed partial denture was a labor intense project--from waxing up the prosthesis--to stacking of the porecelain. For larger frameworks, it was recommended for the dentist to bring in the patient in for a framework try-in. However, advances in both CAD/CAM technology and dental materials are revolutionizing the way dentistry is being done. The following describes the fabrication of a 10-unit full contour zirconia fixed partial denture completed in the pre-doctorate program at UTHSCSA Dental School. PMID:24354167

Zimmermann, Richard; Seitz, Stefanie; Magness, Brent; Wieck, Blaine

2013-10-01

58

Effect of the Number of Implants on Stress Distribution of Anterior Implant-Supported Fixed Prostheses Combined with a Removable Partial Denture: A Finite Element Analysis  

PubMed Central

Objective: The main goal of this study was to evaluate differences in stress distribution relevant to the number of implants under an anterior bridge when combined with a removable partial denture in the posterior region. Materials and Methods: Four three-dimensional finite element models (3D FEM) were designed from a mandible containing an implant-supported bridge extending between canines, and a bilateral distal extension removable partial denture. A nonrigid connection was selected as the attachment method between the partial denture and the anterior implant-supported fixed prosthesis; 2, 3, 4 and 5 implants supporting the bridge all with 10mm length and 3.8 mm diameter were assessed. With the aid of the finite element program ANSYS 8.0, the models were loaded and von Mises stresses were evaluated. Results: In spongy bone, stress forces showed a decrease from 2 implants to 4 implants but showed an increase in the 5-implant model. Stresses on cortical bone of terminal implants were in similar range in the 2-, 3- and 4-implant models. While, in the 5-implant model the amount of stresses on terminal implants increased dramatically. The stresses on implants were nearly similar in all models, with the greatest amount on terminal implants. Conclusion: Within the limitations of this study, 2-, 3- and 4-implant models showed less stress on cortical and spongy bone in comparison with the 5-implant model. The stresses transferred to implants were nearly similar.

Mahshid, Minoo; Geramy, Allahyar; Ejlali, Massoud; Sedaghat Monfared, Majid; Rezvani Habib Abadi, Shirin

2014-01-01

59

Dislodgement resistance of modified resin-bonded fixed partial dentures utilizing tooth undercuts: an in vitro study  

PubMed Central

STATEMENT OF PROBLEM Over the years, resin-bonded fixed partial dentures (RBFPDs) have gone through substantial development and refinement. Several studies examined the biomechanics of tooth preparation and framework design in relation to the success rate of RBFPDs and considered retention and resistance form essential for increase of clinical retention. However, these criteria required preparations to be more invasive, which violates not only the original intentions of the RBFPD, but may also have an adverse effect on retention due to loss of enamel, an important factor in bonding. PURPOSE The object of this in vitro study was to compare the dislodgement resistance of the new types of RBFPDs, the conventional three-unit fixed partial denture, and conventional design of RBFPD (Maryland bridge). MATERIAL AND METHODS Fifty resin mandibular left second premolars and second molars were prepared on dentiforms, according to the RBFPD design. After model fabrication (five group, n = 10), prostheses were fabricated and cemented with zinc phosphate cement. After cementation, the specimens were subjected to tensile loading at a cross head speed of 4 mm/min in a universal testing machine. The separation load was recorded and analyzed statistically using one-way analysis of variance followed by Duncan's multiple range test. RESULTS Group V, the pin-retained RBFPDs, had the highest mean dislodgement resistance, whereas specimens of group II, the conventional RBFPDs, exhibited a significantly lower mean dislodgement resistance compared to the other 4 groups (P < .05). There were no significant differences between group I, III, and IV in terms of dislodgement resistance (P > .05). Group V had the highest mean MPa (N/mm2) (P < .05). There was no significant difference between groups I, II, III and IV (P > .05). CONCLUSION Within the limits of the design of this in vitro study, it was concluded that: 1. The modified RBFPDs which utilizes the original tooth undercuts and requires no tooth preparation, compared with the conventional design of RBFPDs, has significantly high dislodgement resistance (P < .05). 2. The modified RBFPDs which utilizes the original tooth undercuts and requires minimal tooth preparation, compared with the conventional FPDs, has significantly no difference in retention and dislodgement resistance)(P > .05). 3. The pin-retained FPDs showed a high dislodgement resistance compared to the conventional three-unit FPDs (P < .05). PMID:21165260

Doh, Re-Mee

2009-01-01

60

Effect of connector design on fracture resistance in all-ceramic fixed partial dentures for mandibular incisor region.  

PubMed

Yttrium tetragonal zirconia polycrystal frameworks were prepared for all-ceramic fixed partial dentures (FPDs) for the mandibular incisor region. The effects of the cross-sectional area and morphology of the connector on its strength were evaluated by fracture tests. Nine types of zirconia framework for a 3-unit FPD for a defect of 1 mandibular central incisor were prepared, each differing in cross-sectional area and morphology. Fracture tests were performed by loading until fracture using a universal testing machine. Fracture load was determined and fracture site examined. Significant differences were observed in fracture load according to the morphology and cross-sectional area of the connector (p<0.05, p<0.01, p<0.001). Fracture load differed significantly among all groups according to cross-sectional area, and was also greater when the shape of the connector formed an isosceles triangle widest at the base and the connector had the same height and width. These values still far exceeded 311 N, however, which is the average occlusal force in the incisor region. The results of this study suggest that connector design affects fracture load. PMID:25212560

Murase, Toshihiko; Nomoto, Syuntaro; Sato, Toru; Shinya, Akimasa; Koshihara, Teruyoshi; Yasuda, Hiromitsu

2014-01-01

61

In Vitro Assessment of Single-Retainer Tooth-Colored Adhesively Fixed Partial Dentures for Posterior Teeth  

PubMed Central

The purpose of this paper was to investigate, by means of marginal adaptation and fracture strength, three different types of single retainer posterior fixed partial dentures (FPDs) for the replacement of a missing premolar. Two-unit cantilever FPDs were fabricated from composite resin, feldspathic porcelain, and fiber-reinforced composite resin. After luting procedures and margin polishing, all specimens were subjected to a Scanning Electron Microscopic marginal evaluation both prior to and after thermomechanical loading with a custom made chewing simulator comprising both thermal and mechanical loads. The results indicated that the highest score of marginal adaptation, that is, the closest score to 100% of continuous margins, at the tooth-composite resin interface was attained by the feldspathic porcelain group (88.1% median), followed by the fiber-reinforced composite resin group (78.9% median). The worse results were observed in the composite resin group (58.05% median). Fracture strength was higher in feldspathic porcelain (196N median) when compared to resin composite (114.9 N median). All the fixed prostheses made of fiber-reinforced composite resin detached from the abutment teeth before fracturing, suggesting that the adhesive surface's retainer should be increased. PMID:20652071

Bortolotto, Tissiana; Monaco, Carlo; Onisor, Ioana; Krejci, Ivo

2010-01-01

62

The effect of four sprue shapes on the quality of cobalt-chromium cast removable partial denture frame-works  

PubMed Central

Statement of Problem: Sprue design is a factor that controls the velocity and adequate supply of metal to the mould. Currently various manufacturers recommend different shapes of sprue, which have not been advocated in textbooks and literature is lacking for their routine applications. Purpose: This in vitro study was carried out to determine the efficacy of four sprue shapes in producing complete, void free cobalt-chrome removable partial denture frameworks. Materials and Methods: A brass metal die with a Kennedy class III, modification 1, partially edentulous arch was used and four sprue shapes (Group A-Ribbon, Group B-Square, Group C-Round and Group D- Round with reservoir) were evaluated. 40 refractory casts were made, 10 wax patterns for each sprue design were waxed up, invested with phosphate bonded investment material and castings done with induction casting machine by the same operator under standardized protocols. The cast frameworks were evaluated for 1. The defects observed visually before finishing and polishing procedures, 2. Fit on the master die as seen with naked eye and 3. Defects on radiographic evaluation. Data were tabulated and statistically analyzed with 1-way ANOVA followed by Student ‘t’ test. Results: The results differed significantly (P < 0.0001) between the Groups with maximum defects in the castings of Group A followed in decreasing order by Group B, Group C and Group D. When comparing between the Groups (P < 0.05), the defects in Groups C and D was significantly lower than Group A and Group B. Conclusions: Round sprues with reservoir produced most satisfactory fit of castings with minimum number of internal and external defects. PMID:24014998

Viswambaran, M.; Agarwal, S. K.

2013-01-01

63

Residual ridge resorption, lower denture stability and subjective complaints among edentulous individuals.  

PubMed

Residual ridge resorption in the mandible after tooth loss may lead to worsening of complete denture stability and to various subjective complaints. The aim was to evaluate the association between radiologically assessed residual ridge resorption in the mandible, clinically assessed stability of lower complete denture and subjective complaints among elderly denture wearers. The study population consisted of 326 (115 men and 211 women) edentulous subjects aged 60-78years, all of whom were wearing complete dentures in the mandible. Data on subjective complaints were obtained from questionnaires and interviews. Denture stability was assessed clinically. Residual ridge resorption was analysed from panoramic radiographs. The results showed that women were significantly more often satisfied with their lower dentures and reported fewer problems with eating than men. They also had significantly more often residual ridge resorption than men. Among women, residual ridge resorption was significantly associated with poor chewing ability, low satisfaction with dentures and poor denture stability. Among men, residual ridge resorption did not associate with subjective complaints or denture stability. Poor satisfaction with dentures associated significantly with poor denture stability in both genders. In conclusion, these results highlight the importance of denture maintenance treatment. As the extent of residual ridge resorption in the mandible was the most important factor that increased dissatisfaction with lower complete dentures, it is also important to inhibit the progression of resorption by preventing tooth loss or by using implant-retained dentures. PMID:22289034

Huumonen, S; Haikola, B; Oikarinen, K; Söderholm, A-L; Remes-Lyly, T; Sipilä, K

2012-05-01

64

Biting and Chewing in Overdentures, Full Dentures, and Natural Dentitions  

Microsoft Academic Search

It has been suggested that the provision of dental implants can improve the oral function of subjects with severely resorbed mandibles, possibly restoring function to the level experienced by satisfied wearers of conventional complete dentures. Nevertheless, a quantitative comparison has never been made and can be drawn from the literature only with difficulty, since studies differ greatly in methodology. To

F. A. Fontijn-Tekamp; A. P. Slagter; A. Van Der Bilt; M. A. Van'T Hof; D. J. Witter; W. Kalk; J. A. Jansen

2000-01-01

65

Living with Your Dentures  

MedlinePLUS

... Relining and Rebasing Adjusting to Your Dentures Denture Adhesives When people get dentures for the first time, ... will slip or fall out. Using a denture adhesive can ease some of these worries and can ...

66

Alternative complete-arch cement-retained implant-supported fixed partial denture  

Microsoft Academic Search

Early implant prostheses designs, which used screw-retained metal and acrylic resin structures, frequently left a space between the prosthesis and the soft tissue. Common deficiencies of this design included phonetic and esthetic problems and screw loosening. Cement-retained implant prostheses are also used in partially and completely edentulous patients, and are thought to have optimal occlusion and esthetics. Moreover, cement-retained prostheses

Theresa M. Hofstede; Carlo Ercoli; Michael E. Hagan

1999-01-01

67

Conservative and esthetic cast gold fixed partial dentures-inlay, onlay, and partial veneer retainers, custom composite pontics, and stress-breakers: part I: fundamental design principles.  

PubMed

Although in today's dental world implant restorations are considered the standard of care in the replacement of missing teeth, clinical contraindications and patient nonacceptance of implant placement can be encountered. Several scenarios are discussed here in which a single missing tooth can be restored with conservative fixed partial dentures (FPD) that employ cast gold retainers; each with a customized design in order to preserve tooth structure, maintain esthetics, and provide a long-term prognosis. The abutment teeth are prepared for conservative partial coverage restorations by using Brasseler burs (Brasseler USA, Savannah, GA, USA). Impressions are taken of the preparations, along with any retentive features, utilizing either the Vented Pin Channel technique or the Shooshan Plastic Pin technique. The latter technique utilizes Kodex twist drills and corresponding impression pins (Coltene Whaledent Inc., Mahwah, NJ, USA). The conservative FPD with non-rigid connectors is fabricated by using type III gold alloy. The pontic cage portion is chemically prepared utilizing the Panavia F2.0 cement kit (Kuraray America Inc., Houston, TX, USA) or other dual-polymerizing resin cement and restored with any type of direct composite resin material. A palette of opaquers and tints are used for chairside characterization of the esthetic pontic facing. The final polish of the pontic is completed by using FlexiDisc and FlexiBuff discs (Cosmedent Inc., Chicago, IL, USA). CLINICAL SIGNIFICANCE In cases where an implant restoration is contraindicated for replacement of a single tooth, a semi-precision FPD is a conservative, functional, and esthetic alternative. PMID:20002922

Stevenson, Richard G; Refela, Jane A

2009-01-01

68

Fracture strength of three-unit fixed partial denture cores (Y-TZP) with different connector dimension and design.  

PubMed

True crystalline ceramic materials presently used in restorative dentistry are Al2O3 (alumina) and yttrium-oxide stabilised tetragonal polycrystalline zirconium-dioxide (Y-TZP). To ensure optimal clinical performance, the dimensions of the Fixed Partial Denture (FPD) framework in general and of the connectors in particular, must be adequate. Considered recommendations for connector dimensions for Y-TZP FPDs vary from 2 to 4 mm in occluso-gingival height and 2 to 4 mm in bucco-lingual width. In order to reduce the fracture probability when designing all-ceramic FPDs, the shape of the connector is an important factor to consider. The radius of curvature at the gingival embrasure plays a significant role in the load-bearing capacity. FPDs with small gingival embrasure radii are subjected to high stress concentrations in the connector area during loading, compared to FPDs with large embrasure radii. The aim of this in-vitro study was to investigate how different radii of curvature in the embrasure of the connector area and different connector dimensions could affect the fracture resistance of 3-unit all-ceramic FPDs made of Y-TZP. Forty-eight FPDs in 6 groups of 8 FPDs with different connector design were produced in Procera Zirconia Bridge material. The FPD cores were subjected to heat treatment to simulate veneering. Following cementation, the FPDs were firstly thermocycled for 5,000 cycles, then preloaded for 10,000 cycles and finally loaded to fracture. All the FPDs fractured in the connector area. All the crack propagation which led to fracture started at the gingival embrasure of the connector. Within the limitations of this in-vitro study,the recommended minimum dimension of an anterior 3-unit all-ceramic FPD of Y-TZP is 3 mm in incisal-cervical direction and 2 mm in buccal-lingual direction. By increasing the radius of the gingival embrasure from 0.6 to 0.9 mm, the fracture strength for a Y-TZP FPD with connector dimension 3 x 3 mm increases by 20%. PMID:19994565

Bahat, Zdravko; Mahmood, Deyar J Hadi; Vult von Steyern, Per

2009-01-01

69

[The mechanical behavior and biocompatibility of different modern ideas of partial fixed free-end saddle dentures].  

PubMed

This research is aimed to check the mechanical holding and the biocompatibility at various conceptions of removable partial dentures with free saddles, constituted from satellite alloys. As a matter of fact, the duality of the supporting surface in this kind of dental prosthesis sets biological problems, that one must try to sort out in the best way. It consists of three in vitro experimentations to point out the type or the types of framework answering in the best way to biomechanical and biological requirements. The very same equipment has been used on that three experimentations adapting it to the needs. It's "a machine to overdrive", imagined into the building of "L'Ecole supérieure d'Aéronautique de Toulouse"; this machine is made of an electric engine with an axis of rotation, of two speed reducers giving a motion, of one turn by second, of a knee-joint converting a rotary motion to an alternating motion, of a lever-arm enclosing supporting the weights, of a needle with a foam point which secure the saddles or the strategic zones, of two supporting mandibular and maxillary framework resin patterns, and on the areas representing the osteo-mucosa support capped uniformly with a compressible silicone material of on millimetre thick, of one dynamometer and of an accurate comparator to check the strength used, and the displacement tested zones. The first part consists in testing the amplitude of the saddle displacement and the mobilization of strategic joining areas from various frameworks used. So we can infer the impact on the mucosa during the function. That is why six types of frameworks have been achieved in Wironit satellite alloy showing mechanical qualities admitted to be excellent and to be subject to very accurate experiment conditions with 30 Kz strength (Lundeen and Gibbs, 1982). The results are interpreted through the reading of histograms which X-AXIS represent the points where motions have been located and the Y-AXIS represent the motion at 1/100th millimetre. It allows to show the existence more or less important of the saddle displacement which is not far from the mucosa one and constitute therefore on the biological view point a favourable component but also the existence of tensions in level of some strategic zones which let foresee, for same, a risk of weariness.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:1477512

Lubespere, A; Lebig, A; Jourdan, P

1992-01-01

70

Trial of an experimental castor oil solution for cleaning dentures.  

PubMed

Denture hygiene is essential because denture biofilm is involved in oral infections and systemic diseases. Although there are chemical agents available on the market, none of them have ideal properties and research on such products is still necessary. The aim of this study was to evaluate the efficacy of a castor bean (Ricinus communis)-based solution for removing denture biofilm, compared to two traditional products (sodium hypochlorite and alkaline peroxide). Fifty maxillary complete denture wearers were instructed to brush their dentures after meals and to immerse their dentures once a day in the following solutions: Saline (20 min; control), Polident alkaline peroxide (3 min), NaOCl (20 min) and 2% castor oil solution (20 min). Participants used each solution for a period of 7 consecutive days, according to a random sequence. After each period, the internal surfaces of maxillary complete dentures were stained with a disclosing solution (1% neutral red), photographed and the disclosed biofilm was quantified with the aid of specific software. The influence of treatments on results was verified by the Friedman test (?=0.05). Tested solutions presented significant difference (Fr=51.67; p<0.001). Saline and NaOCl were significantly different (median: 2.0% and 0.0%) whereas Polident and castor oil presented intermediate results (median: 1.0% and 1.5%, respectively). It can be concluded that the castor oil solution tested in this study was comparable to alkaline peroxide in terms of efficiency in denture biofilm removal. PMID:24789291

Andrade, Ingrid Machado de; Andrade, Kelly Machado de; Pisani, Marina Xavier; Silva-Lovato, Cláudia Helena; de Souza, Raphael Freitas; Paranhos, Helena de Freitas Oliveira

2014-01-01

71

Biomechanical comparison of implant retained fixed partial dentures with fiber reinforced composite versus conventional metal frameworks: a 3D FEA study.  

PubMed

Fiber reinforced composite (FRC) materials have been successfully used in a variety of commercial applications. These materials have also been widely used in dentistry. The use of fiber composite technology in implant prostheses has been previously presented, since they may solve many problems associated with metal alloy frameworks such as corrosion, complexity of fabrication and high cost. The hypothesis of this study was that an FRC framework with lower flexural modulus provides more even stress distribution throughout the implant retained fixed partial dentures (FPDs) than a metal framework does. A 3-dimensional finite element analysis was conducted to evaluate the stress distribution in bone, implant-abutment complex and prosthetic structures. Hence, two distinctly different models of implant retained 3-unit fixed partial dentures, composed of Cr-Co and porcelain (M-FPD model) or FRC and particulate composite (FRC-FPD model) were utilized. In separate load cases, 300 N vertical, 150 N oblique and 60 N horizontal forces were simulated. When the FRC-FPD and M-FPD models were compared, it was found that all investigated stress values in the M-FPD model were higher than the values in the FRC-FPD model except for the stress values in the implant-abutment complex. It can be concluded that the implant supported FRC-FPD could eliminate the excessive stresses in the bone-implant interface and maintain normal physiological loading of the surrounding bone, therefore minimizing the risk of peri-implant bone loss due to stress-shielding. PMID:21094484

Erkmen, Erkan; Meriç, Gökçe; Kurt, Ahmet; Tunç, Yahya; Eser, At?l?m

2011-01-01

72

The role of friction in the mechanism of retaining the partial removable dentures with double crown system.  

PubMed

Cylindrical telescopic crowns belong to bolt dentures, because their adhesion strength is based on the friction force. The magnitude of static and slide friction forces depends on the strain within the contact area and properties of materials employed. Friction force value between telescope elements declines in the first phase of wearing period and, subsequently, maintains particular constant value of 8 to 10 N. In the telescopic technique, homo and heterogenic joints are used. The following prosthodontic materials have been examined: goldbase alloys (Degudent Kiss, Degulor M), cobalt-base alloy (Brealloy 270), ceramics (Zircon Oxide, Zirconia) during tribological investigations on FGP composite resin. The cooperating surfaces were moistened with synthetic saliva. The research confirmed the dependence of the static friction coefficient on the contact pressure for the analyzed pairs of materials used in prosthodontics. The biggest effect of the contact pressure on the coefficient of friction value occurs when the ceramic rubs on FGP composite resin. The most stable friction coefficient in the context of contact pressure changes as well as life has been found in the case of the cobalt alloy Brealloy 270. An interesting material is a gold alloy Degulor M, for which the coefficient of friction varies only slightly with pressure in the range of 0.6 to 0.9 MPa. PMID:24479667

D?browa, Tomasz; Dobrowolska, Anna; Wieleba, Wojciech

2013-01-01

73

Zirconia-based dental crown to support a removable partial denture: a three-dimensional finite element analysis using contact elements and micro-CT data.  

PubMed

Veneer fracture is the most common complication in zirconia-based restorations. The aim of this study was to evaluate the mechanical behavior of a zirconia-based crown in a lower canine tooth supporting removable partial denture (RPD) prosthesis, varying the bond quality of the veneer/coping interface. Microtomography (?CT) data of an extracted left lower canine were used to build the finite element model (M) varying the core material (gold core - MAu; zirconia core - MZi) and the quality of the veneer/core interface (complete bonded - MZi; incomplete bonded - MZi-NL). The incomplete bonding condition was only applied for zirconia coping by using contact elements (Target/Contact) with 0.3 frictional coefficients. Stress fields were obtained using Ansys Workbench 10.0. The loading condition (L = 1 N) was vertically applied at the base of the RPD prosthesis metallic support towards the dental apex. Maximum principal (?max) and von Mises equivalent (?vM) stresses were obtained. The ?max (MPa) for the bonded condition was similar between gold and zirconia cores (MAu, 0.42; MZi, 0.40). The incomplete bonded condition (MZi-NL) raised ?max in the veneer up to 800% (3.23 MPa) in contrast to the bonded condition. The peak of ?vM increased up to 270% in the MZi-NL. The incomplete bond condition increasing the stress in the veneer/zirconia interface. PMID:25331825

Rocha, Eduardo Passos; Anchieta, Rodolfo Bruniera; de Almeida, Erika Oliveira; Freitas, Amilcar Chagas; Martini, Ana Paula; Sotto-Maior, Bruno Sales; Luersen, Marco Antonio; Ko, Ching Chang

2014-10-21

74

Effect of tea, coffee and turmeric solutions on the colour of denture base acrylic resin: an in vitro study.  

PubMed

Discoloration of acrylic resin denture base when it comes in contact with various food materials and beverages in the oral cavity may cause aesthetic concern to a denture wearer. The objective of this study was to evaluate the effect of tea, coffee and turmeric solutions on the colour of different brands of heat cure acrylic resin denture base materials commonly used in India. Spectrophotometer was used to evaluate the colour change. A significant difference was found when change in colour was statistically analysed. PMID:23997464

Singh, S V; Aggarwal, Priyanki

2012-09-01

75

Processing complete dentures.  

PubMed

The processing of acrylic resin dentures is an exacting art but is relatively simple to carry out to perfection day after day, even when several dentures are processed at the same time. Nine salient factors in the proper processing of acrylic resin dentures were sequentially listed. Unfortunately, a number of these technical procedures are frequently overlooked or shortcuts may be substituted. Herein lie the causes of some hitherto unexplained clinical failures attributed to the acrylic resin denture base material. The acrylic resin denture base materials have been and are currently the best plastic for making dentures. This material has many unique assets and few faults. Its fine properties are often overlooked by the dentist who has several edentulous patients experiencing problems with dentures he made for them. Sore spots, faulty occlusion, looseness, and even breakage are most likely due to inadequate mouth conditioning or poor impressions, incorrect jaw relations, or the dentist's failure to remount the dentures prior to insertion. We have sufficient knowledge and scientific evidence to realize that most, if not all, denture problems are caused by the dentist's technique or by dentist-patient relationship. These problems should not be attributed to the acrylic resin material nor to the hard-working, conscientious dental laboratory technician. I doubt that more than 2 per cent of all complete denture difficulties experienced by frustrated patients would be solved by the introduction and availability of a new perfect denture base material. PMID:321278

Woelfel, J B

1977-04-01

76

[Photoelastic stress analysis of fixed-removable partial denture which had bar and Ceka-Anchor attachment].  

PubMed

In our study, we constructed fixed-removable partial prosthesis, which are supported by teeth and tissue for patients who exhibited extensive tissue loss. In these prosthesis the localization of the precision attachments on the bar and the stress conducted to the abutment teeth by changing the number of splinted teeth and inclination of the bar were compared with photoelastic analyses and the results were evaluated. The photoelastic material used was Araldite/B and its catalyst was HT 901 fitalic anhydrate. The models constructed with these materials were examined in photoelastic polariscope and fringes occurred due to the force applied were photographed and analyzed. PMID:2700117

Yurdukoru, B; Uçta?li, S

1989-05-01

77

Effect of Patient's Personality on Satisfaction with Their Present Complete Denture and after Increasing the Occlusal Vertical Dimension: A Study of Edentulous Egyptian Patients  

PubMed Central

Complete denture wearers often find it difficult to accept a new denture. Personality traits are among the factors that possibly affect patient satisfaction with a complete denture. Our aim was to investigate the influence of patients' personality on satisfaction with their present denture and after an increase in the occlusal vertical dimension (OVD). Sixty edentulous patients with complete dentures (22 men and 38 women, mean age 66 years, and range 50–75 years) participated in the study. The age of their complete dentures ranged from 5 to 16 years. Patients' personalities were evaluated using the Arabic version of the Eysenck Personality Questionnaire. Their satisfaction with their dentures before and after restoration of the OVD and relining of the mandibular denture was evaluated using two questionnaires (I and II), Patients with a high score of neuroticism were less satisfied with their original dentures and after relining and an increase of OVD compared with patients with an average score in that trait. The personality trait of psychoticism was significant to patients' acceptance of an increase in OVD; that is, patients with a high score were less satisfied with their dentures after increase of OVD than patients with an average score. It is concluded that personality traits affect patients' acceptance of their complete dentures. PMID:25110475

Fouda, Shaimaa M.; Al-Attar, Mohamed S.; Virtanen, Jorma I.; Raustia, Aune

2014-01-01

78

Metal-ceramic screw-retained implant fixed partial denture with intraoral luted framework to improve passive fit.  

PubMed

Passive fit of a long-span screw-retained implant prosthesis is an important criteria for the success of the restoration. This article describes a technique for fabricating a ceramometal implant fixed dental prosthesis (FDP) for a long-span partially edentulous situation by altering the conventional screw-retained design. The possibility of a passive fit is maximized by intraoral luting of the cast frame to milled abutments, and the potential framework distortion during fabrication is compensated to a major extent. Retrievability is ensured by screw retention of the prosthesis to the implants. Compared with conventional porcelain fused to metal screw-retained FDP, this prosthesis is relatively inexpensive to fabricate. PMID:20932151

Baig, Mirza Rustum; Gunaseelan, Rajan

2012-04-01

79

Effect of Denture-Related Stomatitis Fluconazole Treatment on Oral Candida albicans Susceptibility Profile and Genotypic Variability  

PubMed Central

Denture-related stomatitis (DRS) is the most common condition affecting removable-denture wearers, and Candida albicans the most frequent pathogenic agent. Systemic antifungal treatment is indicated but recurrences are frequent. The aim of this study was to characterize the oral load, fluconazole susceptibility profile and genotypic variability of oral C. albicans isolates from patients with DRS before (T0), immediately after fluconazole treatment (Tat) and after 6-months follow-up (T6m). Eighteen patients presenting DRS and treated with fluconazole were followed at the Faculty of Dentistry of Oporto University. Seventy C. albicans isolates were obtained and identified using standard cultural and biochemical multi-testing. Fluconazole susceptibility was tested by E-test®. Microsatellite-primed PCR was performed to assess the genotypic variability of C. albicans isolates. The patients’ mean age was 58.0±3.2 years, and 55.6%/44.4% had total/partial dentures. Before treatment, 22.2%, 44.4% and 33.3% of the patients presented DRS type I, II or III, respectively. Fluconazole treatment healed or improved DRS in 77.8% of the patients, accompanied by an 83.5% reduction in oral C. albicans load. However, after 6-months, oral C. albicans load increased significantly and DRS severity was similar to the one observed before treatment. Moreover, the prevalence of patients presenting fluconazole resistant isolates of C. albicans increased significantly throughout the study: T0-5.6%, Tat-10.0% and T6m-42.9%. A change in the genotypic variability of C. albicans isolates was also verified, being mostly associated to fluconazole susceptibility profile change. In conclusion, fluconazole presents a good short-term DRS treatment efficiency, but may be associated to a long-term emergence of C. albicans fluconazole resistance.

Figueiral, Maria Helena; Fonseca, Patrícia; Lopes, Maria Manuel; Pinto, Eugénia; Pereira-Leite, Teresa; Sampaio-Maia, Benedita

2015-01-01

80

Influence of denture plaque biofilm on oral mucosal membrane in patients with chronic obstructive pulmonary disease.  

PubMed

Patients with chronic obstructive pulmonary disease (COPD) have the lower airways colonized with pathogenic bacteria in a stable period of the disease and during exacerbations. The etiology of bacterial exacerbations of COPD depends on the underlying disease, the frequency of exacerbations and antibiotic therapy. Microorganisms can be aspirated off the denture plaque biofilm into the lower respiratory tract and could reduce the patient's immunity and cause pneumonia. COPD patients, who are using acrylic dentures in oral cavity, are exposed to denture stomatitis and oral candidiasis. The aim of this study was to establish the composition of denture plaque biofilm and its impact on the oral mucosa in COPD patients. The study included patients in a stable phase of COPD using removable denture and the control group included healthy wearer's appliances. Examinations concerned the oral mucosal membrane and the hygienic condition of prosthetic restorations. Microbiological examinations were performed by taking a direct swab from the surface of acrylic dentures. Seventeen bacterial and fungal strains were isolated from denture plaque of COPD patients, which could be a reservoir of pathogens in the upper and lower airways. The results showed a greater frequency of prosthetic stomatitis complicated by mucosal infections among COPD patients compared to healthy subjects. PMID:25252900

Przyby?owska, D; Mierzwi?ska-Nastalska, E; Rubinsztajn, R; Chazan, R; Rolski, D; Swoboda-Kope?, E

2015-01-01

81

Conservative and esthetic cast gold fixed partial dentures-inlay, onlay, and partial veneer retainers, custom composite pontics, and stress breakers: part II: utilization of additional retentive features and fabrication of custom pontic facings.  

PubMed

Although in today's dental world implant restorations are considered the standard of care in the replacement of missing teeth, clinical contraindications and patient nonacceptance of implant placement can be encountered. Several scenarios are discussed here in which a single missing tooth can be restored with conservative fixed partial dentures (FPD) that employ cast gold retainers; each with a customized design in order to preserve tooth structure, maintain esthetics, and provide a long-term prognosis. The abutment teeth are prepared for conservative partial coverage restorations by using Brasseler burs (Brasseler USA, Savannah, GA, USA). Impressions are taken of the preparations, along with any retentive features, utilizing either the Vented Pin Channel technique or the Shooshan Plastic Pin technique. The latter technique utilizes Kodex twist drills and corresponding impression pins (Coltene Whaledent Inc., Mahwah, NJ, USA). The conservative FPD with non-rigid connectors is fabricated by using type III gold alloy. The pontic cage portion is chemically prepared utilizing the Panavia F2.0 cement kit (Kuraray America Inc., Houston, TX, USA) or other dual-polymerizing resin cement and restored with any type of direct composite resin material. A palette of opaquers and tints are used for chairside characterization of the esthetic pontic facing. The final polish of the pontic is completed by using FlexiDisc and FlexiBuff discs (Cosmedent Inc., Chicago, IL, USA). CLINICAL SIGNIFICANCE In cases where an implant restoration is contraindicated for replacement of a single tooth, a semi-precision FPD is a conservative, functional, and esthetic alternative. PMID:20002923

Stevenson, Richard G; Refela, Jane A

2009-01-01

82

ACANTHAMOEBA GUIDANCE DOCUMENT FOR CONTACT LENS WEARERS  

EPA Science Inventory

The document reviews the risk of Acanthamoeba Keratitis for contact lens wearers. The document also reviews Granulomatous Amebic Encephalitis, another disease associated with Acanthamoeba in immune compromised individuals. Reports indicate that keratitis due to Acanthamoeba is a ...

83

Prosthodontic Management of Flat Mandibular Ridge by Mini Implant Supported Over Denture  

PubMed Central

Loosening of lower denture has always been a common complaint of denture wearer, particularly in case of severe bone resorption. Various treatment modalities including preprosthetic surgery or ridge augmentation therapy to improve the ridge height and conventional implant treatments are available. But many patients are not willing to undergo through such extensive surgical procedure or conventional twin stage implant therapy owing to the chronic old age ailment and cost factor. So mini implant (SENDAX MDI) supported over denture is a boon for them who want a quick and minimally invasive solution, with a much lower cost. In this article we shall discuss the case report of a 60-year-old female patient with atropic mandibular ridge rehabilitated with MDI, (mini dental implant), Sendax mini implant. PMID:25177653

Garhnayak, Lokanath; Dev, Shruti; Kar, Aswini Kumar; Mohapatra, Abhijita

2014-01-01

84

Denture-Induced Stomatitis  

MedlinePLUS

... cleaning habits A build-up of the yeast Candida albicans , which can cause an infection Denture-induced ... They are more likely to be infected with Candida . People who smoke and those who do not ...

85

Management of flabby ridges using liquid supported denture: a case report  

PubMed Central

Flabby ridges commonly occur in edentulous patients. Inadequate retention and stability of a complete denture are the often encountered problems in these patients. A liquid supported denture due to its flexible tissue surface allows better distribution of stress and hence provides an alternate treatment modality in such cases. This case report presents the use of a liquid supported denture in a patient with completely edentulous maxillary arch with flabby tissue in anterior region opposing a partially edentulous mandibular arch. PMID:21503193

Aras, Meena Ajay; Chitre, Vidya

2011-01-01

86

Antifungal activity, biofilm-controlling effect, and biocompatibility of poly(N-vinyl-2-pyrrolidinone)-grafted denture materials.  

PubMed

Colonization and biofilm-formation of Candida species on denture surfaces cause Candida-associated denture stomatitis (CADS), a common, recurring disease affecting up to 67% of denture wearers. We developed poly(N-vinyl-2-pyrrolidinone)-grafted denture materials that can be repeatedly recharged with various antifungal drugs to achieve long-term antifungal and biofilm-controlling effects. The monomer, N-vinyl-2-pyrrolidinone (NVP), was grafted onto poly(methyl methacrylate) denture resins through plasma-initiated grafting polymerization. The physical properties and biocompatibility of the resulting resins were not negatively affected by the presence of up to 7.92% of grafted poly (N-vinyl-2-pyrrolidinone) (PNVP). Miconazole and chlorhexidine digluconate (CD) were used as model antifungal drugs. PNVP grafting significantly increased the drug absorption capability of the resulting denture materials. Further, the new materials showed sustained drug release and provided antifungal effects for weeks (in the case of CD) to months (in the case of miconazole). The drug-depleted resins could be recharged with the same or a different class of antifungal drug to further extend antifungal duration. If needed, drugs on the PNVP-grafted denture materials could be "washed out" (quenched) by treating with PNVP aqueous solutions to stop drug release. These results point to great potentials of the new materials in controlling biofilm-formation in a wide range of device-related applications. PMID:23708753

Sun, Xinbo; Cao, Zhengbing; Yeh, Chih-Ko; Sun, Yuyu

2013-10-01

87

Antifungal activity, biofilm-controlling effect, and biocompatibility of poly(N-vinyl-2-pyrrolidinone)-grafted denture materials  

PubMed Central

Colonization and biofilm-formation of Candida species on denture surfaces cause Candida-associated denture stomatitis (CADS), a common, recurring disease affecting up to 67% of denture wearers. We developed poly(N-vinyl-2-pyrrolidinone)-grafted denture materials that can be repeatedly recharged with various antifungal drugs to achieve long-term antifungal and biofilm-controlling effects. The monomer, N-vinyl-2-pyrrolidinone (NVP), was grafted onto poly(methyl methacrylate) denture resins through plasma-initiated grafting polymerization. The physical properties and biocompatibility of the resulting resins were not negatively affected by the presence of up to 7.92% of grafted poly (N-vinyl-2-pyrrolidinone) (PNVP). Miconazole and chlorhexidine digluconate (CD) were used as model antifungal drugs. PNVP grafting significantly increased the drug absorption capability of the resulting denture materials. Further, the new materials showed sustained drug release and provided antifungal effects for weeks (in the case of CD) to months (in the case of miconazole). The drug-depleted resins could be recharged with the same or a different class of antifungal drug to further extend antifungal duration. If needed, drugs on the PNVP-grafted denture materials could be “washed out” (quenched) by treating with PNVP aqueous solutions to stop drug release. These results point to great potentials of the new materials in controlling biofilm-formation in a wide range of device-related applications. PMID:23708753

Sun, Xinbo; Cao, Zhengbing; Yeh, Chih-Ko; Sun, Yuyu

2013-01-01

88

The bond strength of a visible light-cured reline resin to acrylic resin denture base material.  

PubMed

The introduction of Triad visible light-cured denture resin has led to several applications. Among them is direct intraoral relining of complete and partial dentures. This study investigated the bonding characteristics of Triad reline resin to four commonly used heat-cured denture base resins. The shear and tensile bond strengths of Triad resin and four denture base resins were determined and compared with intact tensile strengths. The findings of this study indicate that the bond strength of Triad resin to denture base resin is sufficiently high to suggest its clinical applicability. PMID:2184235

Razavi, R; Khan, Z; von Fraunhofer, J A

1990-04-01

89

Hollow maxillary complete denture.  

PubMed

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. The resorption occurs at a faster rate in mandibular arch as compared to the maxillary arch; but severely atrophic maxillae with large interridge distance often pose a clinical challenge during fabrication of a successful maxillary complete denture. This clinical report describes a simple technique of fabricating a hollow maxillary complete denture in a patient with resorbed maxillary and mandibular ridges with increased interridge distance which reduces the weight of the prosthesis and thereby enhances the retention. PMID:23204735

Radke, Usha; Mundhe, Darshana

2011-12-01

90

Infective keratitis in soft contact lens wearers.  

PubMed Central

Eight cases of infective keratitis are reported in wearers of soft contact lenses. Four of them had normal eyes and were wearing lenses on a continual basis. One was wearing a lens continually for therapeutic reasons. Three others were wearing lenses daily or intermittently. The four latter cases were using contaminated lens solutions. Two of the continual lens wearers lost vision to the point of blindness. A significant factor in their bad outcome was the fact that both lived in areas remote from adequate ophthalmic services. Serratia liquefaciens was implicated in one case. This is thought to be the only reported case of corneal abscess due to this organism in the past 16 years. S. marcescens was grown in another case from the lens solutions and carrying case. Images PMID:403931

Cooper, R L; Constable, I J

1977-01-01

91

Superior limbic keratoconjunctivitis in contact lens wearers.  

PubMed

Forty patients with daily wear, cosmetic contact lenses (CL) presented with symptoms of ocular irritation and a keratoconjunctivitis clinically resembling superior limbic keratoconjunctivitis (SLK). Typically the patients were either successful hard CL wearers who changed to soft lenses and used a chemical aseptisizing solution or preserved saline solution, or successful soft CL wearers using salt tablets who switched to a preservative-containing system. In all cases, exposure to thimerosal-preserved solutions was documented. Upon discontinuation of lens wear, all signs and symptoms slowly resolved without permanent sequelae. Positive skin and ocular sensitivity reactions to thimerosal were present in one-third (5/15) of patients tested. Light and transmission electron microscopic examination of conjunctival specimens disclosed intercellular epithelial edema, pseudoepitheliomatous hyperplasia, acute and chronic inflammation, and decreased numbers of goblet cells. Exposure to thimerosal is implicated in the etiology of contact lens-superior limbic keratoconjunctivitis (CL-SLK). PMID:6888855

Sendele, D D; Kenyon, K R; Mobilia, E F; Rosenthal, P; Steinert, R; Hanninen, L A

1983-06-01

92

The denture box. An aid to denture hygiene.  

PubMed

This paper re-visits the need for patients or their carers to maintain as low a level of denture biofilm as possible. It notes that the handling of dentures is unpleasant to carers and suggests a method of reducing this contact to a minimum but yet allow efficient cleaning by means of brushing. It also highlights the potential damage that can occur due to mishandling or accident. The denture box acts as a safe storage unit and finally, it suggests that its 'footprint' allows accurate recovery in an institution where dentures can be inadvertently mingled. PMID:25571813

Faigenblum, M J

2015-01-01

93

Tear analysis in contact lens wearers.  

PubMed Central

Tear analysis in contact lens wearers was compared with tear analysis in aphakics without contact lens wear and normal phakic patients. Subjects were divided into five groups: group 1, aphakic without contact lens; group 2, phakic with daily-wear hard contact lens; group 3, phakic with daily-wear soft contact lens; group 4, phakic with extended-wear soft contact lens; and group 5, aphakic with extended-wear soft contact lens. The experimental groups were compared with age- and sex-matched control groups for statistical analysis of tear variables by means of the Student's t-test. The variables measured were tear osmolarity, tear albumin, and lysozyme and lactoferrin concentrations in basal and reflex tears. Highly significant elevations of tear osmolarity were found in aphakic subjects without contact lenses. Less significant differences in tear osmolarity were found in phakic subjects with hard daily-wear lenses or with extended-wear soft lenses. Tear albumin, lysozyme, and lactoferrin in basal and reflex tears were not significantly different in the different groups of contact lens wearers or in the group of aphakic subjects without contact lenses compared with their control groups. Individual variations in tear albumin, lysozyme, and lactoferrin appeared to be responsible for the inability to demonstrate significant differences in tear composition in association with the wearing of different types of contact lenses. Older and aphakic patients demonstrated a tendency to have increased concentrations of proteins in the tears compared with younger, phakic contact lens wearers and normal controls without contact lenses. PMID:3914131

Farris, R L

1985-01-01

94

Bonding of acrylic denture teeth to resin denture bases.  

PubMed

Anterior teeth debonding from dentures is a common problem. This study tested the bond strength of denture teeth to two types of denture resin, with and without grooving the ridge-lap surface. Bond strength and fracture type of three different groups were compared: 1. Teeth bonded to heat-cured polymethyl methacrylate (PMMA); 2. Teeth bonded to pour-type PMMA; 3. Grooved teeth bonded to pour-type PMMA. Specimens were manufactured following ISO standard 22112. Force values at failure were analysed using one-way analysis of variance, using the mixed procedure with confidence interval of 95%. Types of failure were identified as adhesive, cohesive or combination. In descending order, mean failure forces were 418.55N (Group One), 367.55N (Group Two) and 290.05N (Group Three). There was no significant difference between the means of groups 1 and 2 (p = 0.0627). Group Three differed from both other groups (p < 0.001). Groups One and Two showed predominantly cohesive fractures wthin denture teeth (83% and 72% respectively); group Three showed predominantly cohesive fractures within the denture PMMA (75%). Without ridge-lap modification, the bond strengths of denture teeth to pour-type and heat-cured denture resin were similar. Failures were predominantly of cohesive nature within the teeth themselves. Grooving the ridge-lap reduced fracture resistance and led to breakages predominantly in denture PMMA. PMID:23185939

Geerts, G A V M; Stuhlinger, M E

2012-07-01

95

Hollow Maxillary Complete Denture  

Microsoft Academic Search

Residual ridge resorption is the reduction in size of the bony ridge under the mucoperiosteum. The resorption occurs at a\\u000a faster rate in mandibular arch as compared to the maxillary arch; but severely atrophic maxillae with large interridge distance\\u000a often pose a clinical challenge during fabrication of a successful maxillary complete denture. This clinical report describes\\u000a a simple technique of

Usha Radke; Darshana Mundhe

96

Zinc toxicity: denture adhesives, bone marrow failure and polyneuropathy.  

PubMed

A 36-year-old female developed bone marrow failure diagnosed as myelodysplastic syndrome (MDS) (Sidebar), followed shortly by a peripheral neuropathy and a gait disturbance. While waiting for a bone marrow transplant, she reported to us that she had seen attorney-generated, televised advertisements concerning the role of denture adhesives relating to her malady. Labs were then obtained demonstrating she had dramatic and unsuspected hypocupremia and hyperzincemia. Administration of copper and cessation of denture adhesives resulted in recovery of her hematopoietic system and partial resolution of the neurological sequela. PMID:22375440

Crown, Loren A; May, Jeffery A

2012-02-01

97

Foldable Denture: For Microstomia Patient  

PubMed Central

Microstomia may result from surgical treatment of orofacial neoplasms, cleft lips, maxillofacial trauma, burns, radiotherapy, or scleroderma. A maximal oral opening that is smaller than the size of a complete denture can make prosthetic treatment challenging. This clinical paper presents the prosthodontic management of a total edentulous patient with microstomia. Sectional mandibular and maxillary trays and foldable mandibular and maxillary denture were fabricated for the total edentulous patient. PMID:22957279

Kumar, Sandeep; Arora, Aman; Yadav, Reena

2012-01-01

98

Investigating Biofilm Production, Coagulase and Hemolytic Activity in Candida Species Isolated From Denture Stomatitis Patients  

PubMed Central

Objective: Oral candidiasis, in the form of Candida-associated denture stomatitis, represents a common disease in a large percentage of denture wearers, and Candida albicans remains the most commonly isolated species. In this study, we aimed to evaluate biofilm production, coagulase and hemolytic activity of Candida species isolated from denture stomatitis patients. Materials and Methods: This study included 70 patients (31 female, 39 male). Forty-eight of the patients were found to have a positive culture. A total of 48 Candida isolates representing five species, C. albicans (n=17), C. glabrata (n=10), C. krusei (n=9), C. kefyr (n=7) and C. parapsilosis (n=5), were tested. Their coagulase activities were evaluated by a classical tube coagulase test with rabbit plasma. A blood plate assay on 3% enriched sheep blood Sabouraud-dextrose agar (SDA) was used to determine their in vitro hemolytic activities. Biofilm production was determined by a visual tube method. Results: Twenty-one Candida isolates exhibited coagulase activity, and the coagulase activities of the C. albicans (64.7%) isolates were higher than other species. C. albicans, C. glabrata, C. kefyr and C. krusei species demonstrated beta hemolysis. C. parapsilosis strains failed to demonstrate any hemolytic activities. Fifteen (88.0%) of the C. albicans strains were biofilm positive. Six (35.2%) of these strains were strongly positive, 8 (47.0%) C. albicans strains were moderately positive and 1 (5.8%) C. albicans strain was weakly positive. Sixteen (51.6%) of the non-albicans Candida strains were biofilm positive while 15 (48.3%) did not produce biofilms. Conclusion: The results of this present study indicate coagulase, hemolytic activity and biofilm production by Candida spp. isolated from patients with denture stomatitis. Investigations of these virulence factors might be helpful in gaining information about the possible virulence of oral Candida species related to denture stomatitis.

Yigit, Nimet; Aktas, Esin; Dagistan, Saadettin; Ayyildiz, Ahmet

2011-01-01

99

19th century denture base materials revisited.  

PubMed

Dentistry in the 19th century witnessed the development of a variety of denture base materials, the aim being to find a suitable substitute for the expensive and technique-sensitive noble metal denture bases. The century was marked by the introduction of natural and plastic materials for use as denture bases. Naturally-occurring materials, especially vulcanite, enjoyed great popularity for over 100 years. This article makes an attempt to summarize the historical 19th-century denture base materials. PMID:21563724

Ladha, Komal; Verma, Mahesh

2011-01-01

100

The physical properties of a polyacetal denture resin.  

PubMed

A polyacetal injection-moulded resin is being marketed for the construction of retentive and supportive components of removable partial dentures (RPDs). Specimens of poly(oxymethylene) cast by commercial laboratories were tested to examine the following physical characteristics: the modulus of elasticity in compression, extension and flexure, stress relaxation, the force displacement behaviour of clasp forms, impact strength and glass transition temperature. Results showed that the material has a flexural modulus lower than that of poly(methylmethacrylate) and is insufficiently rigid to be used as a supporting element for partial dentures. Resin clasps may be resilient enough to engage undercuts for the retention of RPDs but the low flexural modulus requires that the resin be used in greater cross-sectional area than metal alloys in order to gain useful retention. This greater bulk has implications for plaque accumulation and maintenance of periodontal health. PMID:10150599

Fitton, J S; Davies, E H; Howlett, J A; Pearson, G J

1994-01-01

101

21 CFR 872.3590 - Preformed plastic denture tooth.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Preformed plastic denture tooth. 872.3590 Section...Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated...

2011-04-01

102

21 CFR 872.3590 - Preformed plastic denture tooth.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Preformed plastic denture tooth. 872.3590 Section...Prosthetic Devices § 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated...

2010-04-01

103

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2014 CFR

...2014-04-01 2014-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2014-04-01

104

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2012-04-01

105

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2011-04-01

106

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2010-04-01

107

21 CFR 872.3580 - Preformed gold denture tooth.  

Code of Federal Regulations, 2013 CFR

...2013-04-01 2013-04-01 false Preformed gold denture tooth. 872.3580 Section 872...Prosthetic Devices § 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of...

2013-04-01

108

21 CFR 872.3300 - Hydrophilic resin coating for dentures.  

Code of Federal Regulations, 2010 CFR

... 2010-04-01 false Hydrophilic resin coating for dentures. 872.3300 ...Prosthetic Devices § 872.3300 Hydrophilic resin coating for dentures. (a) Identification. A hydrophilic resin coating for dentures is a device...

2010-04-01

109

Problems Faced by Complete Denture-Wearing Elderly People Living in Jammu District  

PubMed Central

Context: Poor oral health is increasing dramatically among old people especially those living in rural and remote areas. Various factors such as low education background, low income, poor living conditions, unhealthy lifestyle, inadequate oral hygiene and tobacco use lead to poor oral health among older people which in turn lead to risks to their general health. The older people especially from rural areas are apprehensive about seeing a dentist and do not visit them regularly. This may lead to various problems which may have a detrimental influence on their quality of life. Aim: To know the problems faced by complete denture wearers in rural areas in Jammu district. Materials and Methods: Fifty patients from rural area Bishna, initially treated with a complete denture in the maxilla or mandibles were examined. The data were collected with the help of a questionnaire. Results: The results revealed that majority of respondents were in the age – group of 65-70 y. Majority of respondents complained of "difficulty chewing", "sore spots”, “painful and swollen gums". Majority of respondents had difficulty in speech, it was difficult for them to interact and communicate with their dentures on. Most of the respondents had lost confidence and had low self esteem. Clinical observations revealed that the commonest condition associated with denture wearing was Oral Stomatitis/ Burning mouth Syndrome, Superimposed infection and Angular cheilitis. Conclusion: Older people should Communicate and visit dentists, regularly, so that the dentists can adjust the treatment and pace according to their needs. Behavioural therapy techniques can make dental visits relatively anxiety and pain-free. PMID:25654025

Sharma, Sumeet; Singh, Sarbjeet; Wazir, Nikhil; Raina, Rajiv

2014-01-01

110

Immunoglobulin Concentration in Tears of Contact Lens Wearers  

PubMed Central

Purpose: To evaluate changes in the concentration of tear immunoglobulins in contact lens wearers. Methods: A total of 45 cases including 23 contact lens wearers (43 eyes) and 22 age and sex matched healthy controls having no ocular pathology were studied for immunoglobulins (IgA, IgG, IgM) in their tears by single radial immunodiffusion method. Results: Most of the cases used soft (56.6%) and semi-soft gas permeable (30.4%) contact lenses. Tear IgM was detected in only 17.4% and tear IgG in 43.6% of contact lens wearers, while in controls IgG was detected in 9.1% but none of the controls had IgM. There was a significant rise in total tear IgA (13.17 ± 4.44 mg/dl) in contact lens wearer as compared to controls (8.93 ± 3.79 mg/dl). Rise of tear IgA was more in symptomatic patients (15.38 ± 5.28 mg/dl) and in those wearing hard (19.73 ± 5.43 mg/dl) and semi-soft contact lenses (13.31 ± 5.43 mg/dl). A significant increase in tear IgA was noticed in subjects wearing lenses for >3 years (15.69 ± 5.39 mg/dl). About 43.4% of lens wearers were symptomatic and 80% of their lenses showed deposits and/or haziness. All cases with IgM in tear were symptomatic. Conclusion: The relation of immunoglobulin concentration with increasing duration of wear and material of contact lens shows that tear immunoglobulin rise accrues due to mechanical stimulation, hence contact lenses should not be used for a long period and lenses of hard nature should be discouraged. The maintenance, cleaning and deproteinization of the lenses are of high importance to avoid immunostimulation.

Maurya, Rajendra P.; Bhushan, Prashant; Singh, Virendra P.; Singh, Mahendra K.; Kumar, Prakash; Bhatia, Ravindra P.S.; Singh, Usha

2014-01-01

111

Development of an in vitro denture plaque biofilm to model denture malodour.  

PubMed

This study aimed to develop an in vitro denture plaque biofilm to model denture malodour. No previous studies have attempted to characterize the malodour associated with dentures and the effect of Candida spp. (main aetiological agent of denture-related stomatitis) on malodour. Pooled denture plaque microcosms and 'model' denture plaque biofilms (pooled saliva supplemented with additional microbial species) with and without addition of candida were grown aerobically at 37 °C for up to 13 days in a constant depth film fermenter (CDFF) on denture acrylic discs. Sample discs were removed, rinsed in sterile water and placed in phosphate buffered saline (PBS). The discs were vortex mixed to remove the biofilms, diluted in PBS and plated in duplicate onto general and selective media. The composition and stability of the biofilms over time were assessed. CDFF-grown microcosms and 'model' denture plaque biofilms were relatively stable in composition, with streptococci remaining the dominant microbial group. Model denture plaque biofilms were comparable in composition to denture plaque microcosms. This model system has the potential for evaluation of agents that might affect these parameters such as denture cleansers and other oral hygiene treatments. PMID:21386148

Coulthwaite, L; Verran, J

2008-03-01

112

Effect of denture adhesive on retention of the mandibular and maxillary dentures during function.  

PubMed

The purpose of this study was to determine the effect of denture adhesive on retention of mandibular and maxillary dentures over a four-hour period. Denture movements were measured using an alternating magnetic field tracking device that determines the position of magnetic receiver coils relative to a transmitter coil positioned over the head. Ten adults with complete maxillary dentures and complete mandibular implant overdentures were enrolled in the study. Specially fabricated mandibular dentures contained a relief area that exposed the implant post which no longer anchored the denture, but now served as an attachment point for a receiver coil that measured mandibular movement. The denture coil was attached lateral to the post coil on a shelf cut into the denture. Mandibular denture movements were recorded as the difference between the mandible movement signal and the mandible + mandibular denture signals. Measurements of denture movements were made at baseline (no adhesive) and at 0, 2, 4 hours post-adhesive application with Fixodent cream for standardized chewing and biting. The MoveTrack signals were recorded on a digital data cassette recorder for subsequent computer analysis. The results of the measurements were analyzed using paired sample t-tests. Specifically, the following comparisons of movement means were made: mandibular vs. maxillary, baseline vs. post-baseline and successive changes (e.g., baseline vs. hour 0, hour 0 vs. hour 2, etc.). Results of these analyses showed that: 1) mandibular denture movements under both adhesive and non-adhesive conditions were significantly greater than maxillary denture movements; 2) the adhesive significantly reduced movement of the maxillary and mandibular dentures during both chewing and biting; and 3) the improvement occurred immediately post-application of the adhesive and was maintained for the four hours of follow-up. PMID:11460279

Grasso, J; Gay, T; Rendell, J; Baker, R; Knippenberg, S; Finkeldey, J; Zhou, X; Winston, J L

2000-01-01

113

Epidemiology of Pseudomonas aeruginosa keratitis in contact lens wearers.  

PubMed Central

This study evaluated the epidemiology of Pseudomonas aeruginosa keratitis in contact lens (CL) wearers; the relationships between CL storage case contamination and CL hygiene practice and between CL hygiene and the development of keratitis. Sixteen CL wearers with keratitis were compared with 44 asymptomatic controls. Lens hygiene practice was assessed and CL care materials, domestic water sites and endogenous sites were evaluated microbiologically. Poor CL hygiene was not associated with Ps. aeruginosa keratitis. There was an association between keratitis and bacterial contamination of the CL and storage case (P < 0.0005). Lens and storage case contamination were not significantly associated with poor hygiene. No domestic or endogenous source for Ps. aeruginosa was found. Causative organisms may be derived from other sources, but CLs and CL storage cases provide a favourable environment for Ps. aeruginosa colonization. Changing the CL care environment to one less favourable for Ps. aeruginosa may help to eliminate this problem. PMID:7781727

Stapleton, F.; Dart, J. K.; Seal, D. V.; Matheson, M.

1995-01-01

114

The conjunctival sensitivity in soft contact lens wearers.  

PubMed

We determined the influence of soft contact lenses (SCLs) on conjunctival sensitivity. A total of 26 volunteers (11 males, 15 females; mean age 28.3 ± 4.6 years; range 22-39 years) without dry eye were enrolled in the study. Subjects with a low corneal touch threshold, atopic keratoconjunctivitis, or vernal keratoconjunctivitis were excluded. In 26 participants, 12 were disposable SCL wearers. Touch thresholds were determined using a Cochet-Bonnet esthesiometer with a 0-60 mm nylon monofilament in 5 mm increments. The length (mm) was converted to tension (g/mm(2)). Mean touch sense thresholds in the SCL wearers (n = 12) and non-wearers (n = 14) were 10.7 ± 2.57 and 24.6 ± 7.3 g/mm(2) in the whole conjunctiva, and 9.07 ± 3.02 and 19.2 ± 7.8 g/mm(2) in the upper palpebral conjunctiva, respectively. Significant differences were observed in all locations (p < 0.01). The enhanced conjunctival sensitivity associated with SCL use may contribute to the dry eye-like symptoms in SCL users who do not have dry eye. PMID:25194462

Igarashi, Tsutomu; Ono, Masafumi; Fujimoto, Chiaki; Suzuki, Hisaharu; Takahashi, Hiroshi

2014-09-01

115

A Novel Mechanism of Increased Infections in Contact Lens Wearers  

PubMed Central

Purpose. It is well documented that contact lens wearers have much higher incidences of corneal infections compared with those of non–contact lens wearers, although the exact cause(s) of this increased susceptibility has not been identified. A distinct subset of mucins (MUCs) is present on the ocular surface, acting to protect the integrity of the corneal epithelium. This study was performed to determine whether multipurpose contact lens solutions (MPCLSs) can cause increased infections in the cornea by destroying the protective cell-bound mucin layer. Methods. An immortalized human corneal limbal epithelial cell line was treated in the presence of four commonly used MPCLSs or PBS and the expression and release of MUC-16 was assessed. Cells were also cultured with Pseudomonas aeruginosa after MPCLS treatment and internalization of bacteria was assessed by quantitative genomic PCR. Loss of MUC-16 was then correlated with infection rates. Results. Each of the four commonly used MPCLSs examined in this study differentially affected mucin release. The relative effect was correlated with an increase in infection of corneal epithelial cells by P. aeruginosa. Conclusions. The results of this study are consistent with the hypothesis that MPCLSs cause increased infections in the cornea by destroying the protective cell-bound mucin layer. PMID:22039229

Gordon, Gabriel M.; Moradshahi, Navid; Jeong, Shinwu; Lane, Christianne

2011-01-01

116

21 CFR 872.3530 - Mechanical denture cleaner.  

Code of Federal Regulations, 2013 CFR

...AC-powered, that consists of a container for mechanically agitating a denture cleansing solution. The device is intended to clean a denture by submersion in the agitating cleansing solution in the container. (b) Classification. Class I...

2013-04-01

117

21 CFR 872.3530 - Mechanical denture cleaner.  

Code of Federal Regulations, 2010 CFR

...AC-powered, that consists of a container for mechanically agitating a denture cleansing solution. The device is intended to clean a denture by submersion in the agitating cleansing solution in the container. (b) Classification. Class I...

2010-04-01

118

21 CFR 872.3530 - Mechanical denture cleaner.  

Code of Federal Regulations, 2014 CFR

...AC-powered, that consists of a container for mechanically agitating a denture cleansing solution. The device is intended to clean a denture by submersion in the agitating cleansing solution in the container. (b) Classification. Class I...

2014-04-01

119

21 CFR 872.3530 - Mechanical denture cleaner.  

Code of Federal Regulations, 2011 CFR

...AC-powered, that consists of a container for mechanically agitating a denture cleansing solution. The device is intended to clean a denture by submersion in the agitating cleansing solution in the container. (b) Classification. Class I...

2011-04-01

120

21 CFR 872.3530 - Mechanical denture cleaner.  

Code of Federal Regulations, 2012 CFR

...AC-powered, that consists of a container for mechanically agitating a denture cleansing solution. The device is intended to clean a denture by submersion in the agitating cleansing solution in the container. (b) Classification. Class I...

2012-04-01

121

Setting and stress relaxation behavior of resilient denture liners  

Microsoft Academic Search

Statement of problem. Resilient denture liners are widely used for the patients who are not comfortable with correctly made conventional hard-based dentures because of thin and relatively nonresilient mucosa or severe alveolar resorption. There are several materials used for denture liners and the efficacy in their use is influenced by their viscoelastic properties. Purpose. This study evaluated the setting behavior

Hiroshi Murata; Rosalina C. Haberham; Taizo Hamada; Norihiro Taguchi

1998-01-01

122

Clinical morbidity and sequelae of treatment with complete dentures  

Microsoft Academic Search

Wearing complete dentures may have adverse effects on the health of both the oral and the denture-supporting tissues. This article is a review of selected literature on the sequelae of treatment with complete dentures in the specific areas of residual ridge resorption, mucosal reactions, burning mouth syndrome, temporomandibular disorders, and patient satisfaction. Recent literature found with a Medline search from

Gunnar E. Carlsson

1998-01-01

123

Factors Related to Patient Satisfaction With Complete Denture Therapy  

Microsoft Academic Search

Background. Except for denture quality, many other factors are related to a patient's satisfaction with complete dentures (CDs). Methods. A total of 222 patients with CDs took a part in this study. A questionnaire divided into 3 parts was completed by both the patients and the dentist, independently. The patients rated their dentures using a scale ranging from 1 to

Asja Celebic; Dubravka Knezovicc-Zlataric; Milan Papic; Vlado Carek; Ivo Baucic; Jasmina Stipetic

124

Light weight dentures: An innovative technique  

PubMed Central

Retention, stability and support are the basic principles on which the success of a complete denture relies. The severely resorbed maxillary and mandibular edentulous arches that are narrow and constricted with increased interarch space provide decreased support, retention and stability. To decrease the leverage, reduction in the weight of the prosthesis was recommended and also found beneficial. This article describes a simple procedure to reduce the weight of maxillary complete denture by use of an autopolymerizing acrylic resin shell which is incorporated during the packing stage. This method has the advantage of being easy and requires very little additional time. Hollow maxillary complete denture considerably reduces the weight of the prosthesis, which in turn prevents transmission of detrimental forces by reducing leverage action. This results in increased retention and stability and up to some extent it also preserves the existing residual alveolar ridge. The technique uses a clear matrix of trial denture to facilitate shaping of dough spacer to ensure an even thickness of acrylic to resist deformation and prevent seepage of saliva into the cavity making this technique more predictable. An autopolymerizing acrylic resin shell which creates hollow space and also has strength. Technique is simple to execute, easy economical and matching the shade of autopolymerizing acrylic resin with heat cures acrylic resin enhances esthetics. Light weight hollow dentures provide healthy and comfortable living for the geriatric edentulous patient. PMID:24808715

Gundawar, Sham; Zamad, Aakanksha; Gundawar, Sneha

2014-01-01

125

Restoration of the partially edentulous mouth — a comparison of overdentures, removable partial dentures, fixed partial dentures and implant treatment  

Microsoft Academic Search

Objectives: Loss of posterior teeth may result in the loss of neuromuscular stability of the mandible, reduced masticatory efficiency, loss of vertical dimension of occlusion and poor aesthetics. Prosthetic rehabilitation should aim at restoring the vertical dimension and increasing the occlusal contact area in the premolar\\/molar region. Overdentures are particularly indicated in patients with a severe loss of periodontal attachment,

E. Budtz-Jörgensen

1996-01-01

126

Stress analysis techniques in complete dentures.  

PubMed

The fracture of acrylic resin dentures remains an unresolved problem. It is known that eventual fracture of an appliance occurs due to crack initiation and propagation from areas of high stress concentration. In order to understand and overcome the problem of fracture, it is important to identify the regions of stress concentration. A number of different methods are used in stress analysis. However, the finite element method, a numerical technique, appears to overcome most of the problems associated with the earlier experimental methods. This article reviews the different techniques and their application to examining stresses in dentures. PMID:7962903

Darbar, U R; Huggett, R; Harrison, A

1994-10-01

127

21 CFR 872.3420 - Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture adhesive.  

Code of Federal Regulations, 2012 CFR

...cationic polyacrylamide polymer denture adhesive. 872.3420 Section 872.3420...cationic polyacrylamide polymer denture adhesive. (a) Identification. A carboxymethylcellulose...cationic polyacrylamide polymer denture adhesive is a device composed of...

2012-04-01

128

21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.  

Code of Federal Regulations, 2011 CFR

...borate with or without acacia denture adhesive. 872.3400 Section 872.3400...borate with or without acacia denture adhesive. (a) Identification. A karaya...borate with or without acacia denture adhesive is a device composed of karaya...

2011-04-01

129

21 CFR 872.3480 - Polyacrylamide polymer (modified cationic) denture adhesive.  

Code of Federal Regulations, 2012 CFR

...polymer (modified cationic) denture adhesive. 872.3480 Section 872.3480...polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture adhesive is a device composed of...

2012-04-01

130

21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.  

Code of Federal Regulations, 2013 CFR

...carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410...carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene...carboxymethylcellulose sodium denture adhesive is a device containing ethylene...

2013-04-01

131

21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.  

Code of Federal Regulations, 2013 CFR

...oxide homopolymer and/or karaya denture adhesive. 872.3450 Section 872.3450...oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of...

2013-04-01

132

21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.  

Code of Federal Regulations, 2012 CFR

...oxide homopolymer and/or karaya denture adhesive. 872.3450 Section 872.3450...oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of...

2012-04-01

133

21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.  

Code of Federal Regulations, 2010 CFR

...borate with or without acacia denture adhesive. 872.3400 Section 872.3400...borate with or without acacia denture adhesive. (a) Identification. A karaya...borate with or without acacia denture adhesive is a device composed of karaya...

2010-04-01

134

21 CFR 872.3420 - Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture adhesive.  

Code of Federal Regulations, 2014 CFR

...cationic polyacrylamide polymer denture adhesive. 872.3420 Section 872.3420...cationic polyacrylamide polymer denture adhesive. (a) Identification. A carboxymethylcellulose...cationic polyacrylamide polymer denture adhesive is a device composed of...

2014-04-01

135

21 CFR 872.3420 - Carboxymethylcellulose sodium and cationic polyacrylamide polymer denture adhesive.  

Code of Federal Regulations, 2013 CFR

...cationic polyacrylamide polymer denture adhesive. 872.3420 Section 872.3420...cationic polyacrylamide polymer denture adhesive. (a) Identification. A carboxymethylcellulose...cationic polyacrylamide polymer denture adhesive is a device composed of...

2013-04-01

136

21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.  

Code of Federal Regulations, 2014 CFR

...borate with or without acacia denture adhesive. 872.3400 Section 872.3400...borate with or without acacia denture adhesive. (a) Identification. A karaya...borate with or without acacia denture adhesive is a device composed of karaya...

2014-04-01

137

21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.  

Code of Federal Regulations, 2011 CFR

...oxide homopolymer and/or karaya denture adhesive. 872.3450 Section 872.3450...oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of...

2011-04-01

138

21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.  

Code of Federal Regulations, 2013 CFR

...borate with or without acacia denture adhesive. 872.3400 Section 872.3400...borate with or without acacia denture adhesive. (a) Identification. A karaya...borate with or without acacia denture adhesive is a device composed of karaya...

2013-04-01

139

21 CFR 872.3400 - Karaya and sodium borate with or without acacia denture adhesive.  

Code of Federal Regulations, 2012 CFR

...borate with or without acacia denture adhesive. 872.3400 Section 872.3400...borate with or without acacia denture adhesive. (a) Identification. A karaya...borate with or without acacia denture adhesive is a device composed of karaya...

2012-04-01

140

21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.  

Code of Federal Regulations, 2011 CFR

...carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410...carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene...carboxymethylcellulose sodium denture adhesive is a device containing ethylene...

2011-04-01

141

21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.  

Code of Federal Regulations, 2010 CFR

...carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410...carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene...carboxymethylcellulose sodium denture adhesive is a device containing ethylene...

2010-04-01

142

21 CFR 872.3480 - Polyacrylamide polymer (modified cationic) denture adhesive.  

Code of Federal Regulations, 2014 CFR

...polymer (modified cationic) denture adhesive. 872.3480 Section 872.3480...polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture adhesive is a device composed of...

2014-04-01

143

21 CFR 872.3480 - Polyacrylamide polymer (modified cationic) denture adhesive.  

Code of Federal Regulations, 2013 CFR

...polymer (modified cationic) denture adhesive. 872.3480 Section 872.3480...polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture adhesive is a device composed of...

2013-04-01

144

21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.  

Code of Federal Regulations, 2010 CFR

...oxide homopolymer and/or karaya denture adhesive. 872.3450 Section 872.3450...oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of...

2010-04-01

145

21 CFR 872.3450 - Ethylene oxide homopolymer and/or karaya denture adhesive.  

Code of Federal Regulations, 2014 CFR

...oxide homopolymer and/or karaya denture adhesive. 872.3450 Section 872.3450...oxide homopolymer and/or karaya denture adhesive. (a) Identification. Ethylene oxide homopolymer and/or karaya denture adhesive is a device composed of...

2014-04-01

146

21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.  

Code of Federal Regulations, 2012 CFR

...carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410...carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene...carboxymethylcellulose sodium denture adhesive is a device containing ethylene...

2012-04-01

147

21 CFR 872.3410 - Ethylene oxide homopolymer and/or carboxymethylcellulose sodium denture adhesive.  

Code of Federal Regulations, 2014 CFR

...carboxymethylcellulose sodium denture adhesive. 872.3410 Section 872.3410...carboxymethylcellulose sodium denture adhesive. (a) Identification. An ethylene...carboxymethylcellulose sodium denture adhesive is a device containing ethylene...

2014-04-01

148

21 CFR 872.3760 - Denture relining, repairing, or rebasing resin.  

Code of Federal Regulations, 2010 CFR

...Denture relining, repairing, or rebasing resin. 872.3760 Section 872.3760...Denture relining, repairing, or rebasing resin. (a) Identification. A denture relining, repairing, or rebasing resin is a device composed of...

2010-04-01

149

Modified functional impression technique for complete dentures  

Microsoft Academic Search

This report describes the use of a removable acrylic resin tray handle that can be easily attached to custom impression trays to produce an improved peripheral sealing zone. This device can be indicated to develop functional impressions for complete dentures using the patient-conducted muscular motion technique. In upper trays, the handle is fixed in the midline with acrylic resin, while

Alexandre Malachias; Cláudia Helena; Valdir Antônio MUGLIA; Carla MORETO

2005-01-01

150

Occupational Health Concerns in the Denture Industry  

Microsoft Academic Search

Concerns were raised by several denturists regarding potential exposure to methyl methacrylate, respirable and inhalable particulate mass, and noise in the processing of dentures. Both the national and provincial denturist associations encouraged testing to be conducted. The American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) time-weighted average (TWA) for methyl methacrylate is 410 mg\\/m. Personal exposures for

Rita E. Korczynski

1998-01-01

151

Tongue support of complete dentures in the elderly  

Microsoft Academic Search

This study aimed to evaluate the tongue’s role in supporting maxillary denture retention, in providing additional stabilization for the mandibular denture, and the tongue’s relationship with the oral health related well-being in elderly complete denture patients. Four hundred elderly subjects, 263 males and 137 females, were enrolled in this study. All were older than 65 years of age, and wore

Yu-Fen Chen; Yi-Hsin Yang; Ji-Hua Lee; Jen-Hao Chen; Huey-Er Lee; Tsau-Mau Chou

152

Effect of surface treatments on shear bond strength of denture teeth to denture base resins  

PubMed Central

Background: Debonding of denture teeth from denture bases is the most common failure in removable dentures. The purpose of this study was to evaluate the effect of surface treatments on shear bond strength of denture teeth to heat-polymerized and autopolymerized denture base resins. Materials and Methods: In this experimental in vitro study, 60 maxillary central incisor acrylic teeth were divided into two groups. Group M was polymerized with heat-polymerized acrylic resin (Meliodent) by compression molding technique and group F was processed by autopolymerized acrylic resin (Futura Gen) by injection molding technique. Within each group, specimens were divided into three subgroups according to the teeth surface treatments (n = 10): (1) ground surface as the control group (M1 and F1), (2) ground surface combined with monomer application (M2 and F2), and (3) airborne particle abrasion by 50 ?m Al2O3 (M3 and F3). The shear bond strengths of the specimens were tested by universal testing machine with crosshead speed of 5 mm/min. Data were analyzed by two-way analysis of variance (ANOVA) and Tukey's honestly significant difference (HSD) tests (P < 0.05). Results: The mean shear bond strengths of the studied groups were 96.40 ± 14.01, 124.70 ± 15.64, and 118 ± 16.38 N for M1, M2, and M3 and 87.90 ± 13.48, 117 ± 13.88, and 109.70 ± 13.78 N for F1, F2, and F3, respectively. The surface treatment of the denture teeth significantly affected their shear bond strengths to the both the denture base resins (P < 0.001). However, there were no significant differences between the groups treated by monomer or airborne particle abrasion (P = 0.29). The highest percentage of failure mode was mixed in Meliodent and adhesive in Futura Gen. Conclusion: Monomer application and airborne particle abrasion of the ridge lap area of the denture teeth improved their shear bond strengths to the denture base resins regardless of the type of polymerization. PMID:24688570

Bahrani, Farideh; Khaledi, Amir Ali Reza

2014-01-01

153

Comparison of the Effect of two Denture Cleansers on Tensile bond Strength of a Denture Liner  

PubMed Central

Statement of Problem: One of the most clinical challenging issues in prosthodontics is debonding of soft liners from the denture base. Purpose: The aim of this study was to evaluate and compare tensile bond strength between soft liner and heat-cured acrylic resin when immersed in two different types of denture cleanser and distilled water, at different period of times. Materials and Method: In this experimental in vivo study, 238 heat-cured acrylic blocks were made. A soft liner was embedded between the acrylic blocks. Samples were divided into four groups: 17 samples were in the control group and were not soaked in any solution .The remaining samples were divided into 3 groups (Distilled water, Calgon and Fittydent). Each group was then subdivided into two subcategories, regarding the immersion time variable; 15 and 45 minutes. All samples were placed in tension force and tensile bond strength was recorded with the testing machine. One- way ANOVA and Tucky HSD post-hoc test were adopted to analyze the yielded data (?> 0.05). Results: Specimens which were immersed in two denture cleansers (Fittydent and Calgon) and in distilled water showed significant difference (p= 0.001) in bonding strength when compared to the control group. The subjects immersed in denture cleanser solutions and distilled water did not reveal any significant difference (p= 0.90). For all groups; most of the bonding failures (72%) were cohesive type. Conclusion: The effect of the denture cleansers and distilled water on the bond strength was not statistically different; however, the difference was significant between the immersed groups with the non-immersed group. Moreover, type of the denture cleanser did not show any effect on the tensile strength. The tensile strength increases with time of immersion. PMID:24724134

Farzin, M; Bahrani, F; Adelpour, E

2013-01-01

154

Myopia progression in adolescent wearers of soft contact lenses and spectacles.  

PubMed

The purpose of this 3-year, randomized clinical trial was to determine the difference in myopia progression in adolescents wearing soft contact lenses over a control group wearing spectacles. A total of 175 adolescents between the ages of 11 and 14 years were randomized into 2 groups, spectacle wearers and soft contact lens wearers. The main result was that the spherical equivalent change between the groups showed no clinical or statistically significant difference. However, when a power vector analysis was used, which uses all the refractive error data, a small but statistically significant (F test = 4.24, T2 = 17.35, p < 0.01) difference between the groups was found (i.e., the refractive error of the spectacle wearers had a slight increase in astigmatism). It can be concluded that soft contact lens wear does not lead to additional myopia progression in adolescents. PMID:10445639

Horner, D G; Soni, P S; Salmon, T O; Swartz, T S

1999-07-01

155

Dry eye symptoms and signs in long-term contact lens wearers.  

PubMed

The aim of this study is to analyze the relationship between the self-reported symptoms and objective signs of dry eye disease in long-term rigid gas-permeable (RGP) or soft contact lens (SCL) wearers. The study included 32 eyes of Caucasian RGP and SCL wearers between the age of 21 and 42 who wore contact lenses continuously on a daily basis for more than 2 years. Symptoms were assessed according to the Ocular Surface Disease Index (OSDI). Clinical assessments included corneal fluorescein staining according to the National Eye Institute (NEI) staining grid, tear film break-up time (TBUT) and Schirmer II test. There were more male (62.5%) than female (37.5%) patients with a higher proportion of RGP wearers among males (40% vs. 17%) in the study. The mean duration of daily lens wear was 10.6 +/- 5.37 hours, with a significantly higher proportion of patients who wore their lenses for prolonged hours in the soft contact lens group (p < 0.05). There was a trend towards a higher proportion of self reported mild and moderate dry eye in females and soft contact lens wearers. No RGP wearer in this study had a NEI corneal staining grid score higher than 2. A moderate negative correlation was found between daily lens wear duration and TBUT (Pearson's coefficient, r = -0.47) as well as Schirmer II values and higher OSDI score, i.e. mild and moderate dry eye categories (r = -0.50). A strong positive correlation was found between and TBUT and Schirmer II values (r = 0.74). The results of the study emphasize the importance of early and accurate diagnosis of dry eye disease for successful long term RGP and SCL contact lens wear which will hopefully motivate future larger scale investigations on dry eye related problems in contact lens wearers. PMID:23837244

Kastelan, Snjezana; Lukenda, Adrian; Salopek-Rabati?, Jasminka; Pavan, Josip; Gotovac, Marta

2013-04-01

156

Effect of Surface Treatment on the Flexural Strength of Denture Base Resin and Tensile Strength of Autopolymerizing Silicone Based Denture Liner Bonded to Denture Base Resin: An In Vitro Study  

Microsoft Academic Search

Silicone based denture liners are superior to acrylic based denture liners but it has a problem of failure of adhesion with\\u000a the denture base. To evaluate the effect on the tensile bond strength of silicone based liner and flexural strength of denture\\u000a base resin when the latter is treated with different chemical etchants prior to the application of the resilient

Saloni Gupta

2010-01-01

157

Reservoir Complete Denture in a Patient with Xerostomia Secondary to Radiotherapy for Oral Carcinoma: A Case Report and Review of Literature  

PubMed Central

Xerostomia refers to a subjective sensation of dry mouth. A variety of factors can cause xerostomia including radiotherapy (RT) given for the treatment of oral carcinoma. Depending on the cause, treatment is provided to a patient suffering from xerostomia. In severe xerostomia salivary substitutes can be used and if the xerostomic patient is edentulous, then reservoir space for artificial salivary substitute can be created in partial as well as complete upper or lower dentures. The methods advocated so far for incorporating reservoir space in mandibular complete denture are costly, time consuming and require extra-laboratory steps. Therefore, the purpose of this article is to report a simpler method for fabrication of mandibular reservoir denture in a 67-year-old edentulous male patient suffering from xerostomia due to RT for oral carcinoma. PMID:24761252

Ladda, R; Kasat, VO; Gangadhar, SA; Baheti, S; Bhandari, AJ

2014-01-01

158

An alternative impression technique for complete dentures.  

PubMed

This article describes a technique for creating adequate space for an even thickness of polyvinyl siloxane (PVS) impression material at the periphery during complete denture impression making. A PVS border molding material is injected around the borders of a custom tray, a 17-?m-thick stretch wrap film is folded into 4 layers, and a tray-shaped piece slightly larger than the size of the custom tray is placed on the tray covering the borders. After the border molding procedure is completed, the film is removed and the definitive impression completed with a medium-viscosity PVS impression material. PMID:24286641

Yilmaz, Burak; Özçelik, Tuncer Burak

2014-02-01

159

Effect of biofilm formation, and biocorrosion on denture base fractures  

PubMed Central

PURPOSE The aim of this study was to investigate the destructive effects of biofilm formation and/or biocorrosive activity of 6 different oral microorganisms. MATERIALS AND METHODS Three different heat polymerized acrylic resins (Ivocap Plus, Lucitone 550, QC 20) were used to prepare three different types of samples. Type "A" samples with "V" type notch was used to measure the fracture strength, "B" type to evaluate the surfaces with scanning electron microscopy and "C" type for quantitative biofilm assay. Development and calculation of biofilm covered surfaces on denture base materials were accomplished by SEM and quantitative biofilm assay. According to normality assumptions ANOVA or Kruskal-Wallis was selected for statistical analysis (?=0.05). RESULTS Significant differences were obtained among the adhesion potential of 6 different microorganisms and there were significant differences among their adhesion onto 3 different denture base materials. Compared to the control groups after contamination with the microorganisms, the three point bending test values of denture base materials decreased significantly (P<.05); microorganisms diffused at least 52% of the denture base surface. The highest median quantitative biofilm value within all the denture base materials was obtained with P. aeruginosa on Lucitone 550. The type of denture base material did not alter the diffusion potential of the microorganisms significantly (P>.05). CONCLUSION All the tested microorganisms had destructive effect over the structure and composition of the denture base materials. PMID:23755339

Ergin, Alper; Ayyildiz, Simel; Cosgun, Erdal; Uzun, Gulay

2013-01-01

160

Assessment of Candida species colonization and denture-related stomatitis in bar- and locator-retained overdentures.  

PubMed

The aim of this study was to assess the prevalence of denture-related stomatitis (DRS) in different attachment-retained overdenture wearers and its association with particular colonizing Candida species. Thirty-seven edentulous patients with implant-supported maxillary or mandibular overdentures were enrolled. A full clinical history was obtained, including details of patients' oral hygiene practices and the levels of erythema based on Newton's classification scale. Swabs were taken from the palate and investigated mycologically to identify the yeast colonies. Quantitative and qualitative microbiological assessments were performed, which included recording the total numbers of colonies (cfu), their color, and their morphological characteristics. Significant differences were found in cfu values between the attachment and inner surfaces of locator- and bar-retained overdentures (P < .05). Candida albicans was the most common species in both evaluations, being isolated from 81.3% of bar-retained overdentures and 38.1% of locator-retained overdentures. DRS developed in all patients using bar-retained overdentures but in only 71.4% of those using locator-retained overdentures. No statistically significant relationship was found between bar and locator attachments according to smoking habit, overnight removal, or plaque and gingival indices (P > .05). PMID:25295886

Kilic, Kerem; Koc, Ayse Nedret; Tekinsen, Fatma Filiz; Yildiz, Pinar; Kilic, Duygu; Zararsiz, Gokmen; Kilic, Erdem

2014-10-01

161

The effect of denture design and fixatives on the retention of mandibular complete dentures tested on a novel in-vitro edentulous model.  

PubMed

The aim of this study was to evaluate the effect of the design (extension and adaptation) of a mandibular complete acrylic denture and the use of denture adhesives using a novel in-vitro edentulous model. The model is a highly anatomically accurate replica based on a moderately resorbed human mandibular edentulous arch. The model has been designed and fabricated by means of an elaborate clinical and technical process that employs synthetic elastomeric materials with properties that attempts to reproduce in-vitro characteristics of the soft tissues overlying the ridges and immediate reflected tissues. This model was used to measure and compare the retention of mandibular dentures ofvarying designs (well-fitting, over- and under-extended) with and without the aid of denture fixatives. Retention tests were conducted with different volumes of artificial saliva at a cross head speed of 50 mm/min with 4 equidistant holding points on the denture occlusal surface, using a universal tensile testing machine in an axial pull direction. The effect of three denture adhesives on denture retention was also tested on the same denture types at different times over a period of 5 hours and beyond. The in-vitro model presented can be effectively used to test the retention of mandibular complete dentures. The speed of dislodgement force and amount of saliva are important variables in mandibular denture retention. The retention of well-fitting dentures was statistically higher than that of ill-fitting dentures. A significantly higher retention force was needed to dislodge mandibular dentures (well and ill-fitting dentures) when using a denture adhesive. PMID:23888529

Johnson, A; Al-Kaisy, N; Miller, C A; Martin, N

2013-06-01

162

21 CFR 872.3520 - OTC denture cleanser.  

Code of Federal Regulations, 2014 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3520...to remove debris from removable prosthetic dental appliances, such as bridges or dentures. The dental appliance is removed from the...

2014-04-01

163

21 CFR 872.3520 - OTC denture cleanser.  

Code of Federal Regulations, 2011 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3520...to remove debris from removable prosthetic dental appliances, such as bridges or dentures. The dental appliance is removed from the...

2011-04-01

164

21 CFR 872.3520 - OTC denture cleanser.  

Code of Federal Regulations, 2013 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3520...to remove debris from removable prosthetic dental appliances, such as bridges or dentures. The dental appliance is removed from the...

2013-04-01

165

21 CFR 872.3520 - OTC denture cleanser.  

Code of Federal Regulations, 2012 CFR

...SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3520...to remove debris from removable prosthetic dental appliances, such as bridges or dentures. The dental appliance is removed from the...

2012-04-01

166

The various methods and benefits of denture labeling  

PubMed Central

Labeled dentures can be important in identifying the owners in case of an accident, loss of memory, states of unconsciousness, being inadvertently misplaced on admission to a hospital or, in identifying the bodies of those who have died in a calamity. Positive identification through labeled dentures plays a key role in forensic scenario. Marking dentures has been considered as an important part of forensic dentistry, although no standardized method is followed. A number of labeling systems are available and can be broadly separated into either surface marking methods or inclusion systems. Each of the commonly described techniques is assessed with respect to their strengths and weaknesses. The more contemporary methods, though hi-tech, are expensive and may not be suitable for all dental practitioners to use. This article reviews the strengths and weaknesses of various methods involved in labeling dentures concluding by recommending that this valuable topic be included in the dental curriculum in India. PMID:21731340

Datta, Pankaj; Sood, Sonia

2010-01-01

167

Subscriber identity module: A new method for denture identification  

PubMed Central

This article describes a technique for placing subscriber identity module into a complete denture. The cards stores information in the form of text messages and contacts which is easily accessible with all mobile devices, thus enabling quicker identification. PMID:24130595

Colvenkar, Shreya

2013-01-01

168

Reactive dentures: a novel approach to decrease residual ridge resorption.  

PubMed

The need for reduction of traumatic forces transmitted through the prosthesis has long been recognised and studies have shown that either a soft acrylic resin/silicone rubber can serve as a stress distributor and absorb some of the forces applied to the teeth. These dentures permit reaction to impacting forces which allows independent movement of one or more teeth in function unlike the conventional dentures. A completely edentulous patient with adequate inter-ridge distance was selected for the case, the dentures with soft liner placed between the patient's teeth and denture base were fabricated. This report presents a completely new technique to reduce the ridge resorption and facilitate patient comfort. PMID:23576651

Reddy, Kesava K; Prasanna, Renuka G S; Sundaresh, K J; Mallikarjuna, Rachappa

2013-01-01

169

The oral hygiene and denture status among residential home residents  

Microsoft Academic Search

The aim of this study was to investigate the oral hygiene practices and denture status of elderly people living in a residential\\u000a home. One hundred one elderly people living in Gurcesme Zubeyde Hanim Residential Home, Izmir—52 women (mean age 75.5?±?7.8)\\u000a and 49 men (mean age 75.3?±?8.8)—participated in an interview. Their oral hygiene practices, self-perceived oral health, denture\\u000a status, and needs

Gülcan Coskun Akar; Safak Ergül

2008-01-01

170

Denture identification using unique identification authority of India barcode  

PubMed Central

Over the years, various denture marking systems have been reported in the literature for personal identification. They have been broadly divided into surface marking and inclusion methods. In this technique, patient's unique identification number and barcode printed in the patient's Aadhaar card issued by Unique Identification Authority of India (UIDAI) are used as denture markers. This article describes a simple, quick, and economical method for identification of individual. PMID:23960418

Mahoorkar, Sudhindra; Jain, Anoop

2013-01-01

171

Clinical gap changes after porcelain firing cycles of zirconia fixed dentures  

PubMed Central

PURPOSE The aim of this study was to measure the changes on the marginal and internal adaptation of zirconia based anterior fixed partial dentures after the porcelain firing process. MATERIALS AND METHODS A total of 34 anterior fixed partial dentures using LAVA CAD/CAM system (3M ESPE, Germany) were applied. Two silicone replicas were obtained: one is obtained before porcelain firing process (initial) and the other is obtained after porcelain firing process (final), followed by the examination under a binocular stereomicroscope. Kruskal Wallis and Wilcoxon Signed Ranks tests were used for the statistical analysis (P<.05). RESULTS No statistically significant difference was found between initial and final marginal gap values (P>.05). At the internal gap measurements, final marginal area values (59.54 µm) were significantly lower than the initial marginal area values (68.68 µm)(P<.05). The highest and the lowest internal gap values were observed at the incisal/occlusal area and at the marginal area, respectively. In addition, lower internal gap values were obtained for canines than for central incisors, lateral incisors and premolars at the incisal area (P<.05). CONCLUSION The firing cycles did not affect the marginal gap of Lava CAD/CAM system, but it is controversial for the internal gap. PMID:25006381

Bugurman, Bugurman Burcu

2014-01-01

172

Analysis of abutment teeth in partially edentulous patients.  

PubMed

The aim of the study was to examine changes in the position of the abutment teeth (AT), size of undercuts for a denture clasp, as well as an existence of an adequate preparation of abutment teeth. A total of 156 casts of partially edentulous jaws, with 460 AT, were analyzed. The size of undercuts, a degree of abutment rotation, inclination and migration were measured using a dental parallelometer. The abutment teeth position was related to the level of occlusal plane in a dental articulator. Furthermore, the existence of an adequate preparation of abutment teeth, as well as a type of a denture and a type of a denture retention element were also considered. Analysis were carried out twice on casts made from a hard stone, the first time before the denture treatment had begun and the second time on the new casts obtained after new dentures had been delivered. The first analysis (prior dental treatment) revealed that a total of 33.9% of the analyzed AT were rotated, 31.3% were inclined, 12.1% had migrated, and 57.3% were elongated above the occlusal plane. On the casts obtained after the new dentures had been made, it was observed that none of the AT had an adequate preparation. Only 37.6% of all retention elements were located in adequate undercut positions on the AT. Upon the results of the present study a conclusion can be established that many abutment teeth are rotated, elongated, inclined, and migrated, which point to a requirement for AT preparation prior the manufacture of new denture; however none of the AT was adequately prepared considering insertion plane and many denture elements were located in an inadequate undercut size. PMID:25145006

Stanci?, Ivica; Popovac, Aleksandra; Rodi?, Teodora; Stipeti?, Jasmina; Strajni?, Ljiljana; Persi?, Sanja

2014-06-01

173

Remedy for Repeated Implant Retained Denture Fracture-A Challenging Case Report  

PubMed Central

The most common site of fracture in a maxillary or a mandibular complete denture is along an anteroposterior line that coincides with the labial notch in in the denture which used to provide the frenum relief. Osseointegrated implants have been a boon to the patients who are completelly edentulous and are not satisfied with the conventional removable complete denture approach.Implant supported dentures have proven to provide superior retention and support for removable complete dentures. Nevertheless, fracture of the denture bases is a common complication of implant-supported mandibular overlay dentures,ecspecially when the artificial denture is opposing natural dentition. This article describes and illustrates a method of reinforcing implant-supported mandibular overdentures to overcome this problem. PMID:25584333

Reddy M, Ramu; Metta, Kiran Kumar; Charry N, Sudheer; B, Chittaranjan

2014-01-01

174

A Randomised Controlled Trial of complete denture impression materials  

PubMed Central

Objectives There is continuing demand for non-implant prosthodontic treatment and yet there is a paucity of high quality Randomised Controlled Trial (RCT) evidence for best practice. The aim of this research was to provide evidence for best practice in prosthodontic impressions by comparing two impression materials in a double-blind, randomised, crossover, controlled, clinical trial. Methods Eighty-five patients were recruited, using published eligibility criteria, to the trial at Leeds Dental Institute, UK. Each patient received two sets of dentures; made using either alginate or silicone impressions. Randomisations determined the order of assessment and order of impressions. The primary outcome was patient blinded preference for unadjusted dentures. Secondary outcomes were patient preference for the adjusted dentures, rating of comfort, stability and chewing efficiency, experience of each impression, and an OHIP-EDENT questionnaire. Results Seventy-eight (91.8%) patients completed the primary assessment. 53(67.9%) patients preferred dentures made from silicone impressions while 14(17.9%) preferred alginate impressions. 4(5.1%) patients found both dentures equally satisfactory and 7 (9.0%) found both equally unsatisfactory. There was a 50% difference in preference rates (in favour of silicone) (95%CI 32.7–67.3%, p < 0.0001). Conclusion There is significant evidence that dentures made from silicone impressions were preferred by patients. Clinical significance Given the strength of the clinical findings within this paper, dentists should consider choosing silicone rather than alginate as their material of choice for secondary impressions for complete dentures. Trial Registration: ISRCTN 01528038.?? This article forms part of a project for which the author (TPH) won the Senior Clinical Unilever Hatton Award of the International Assocation for Dental Research, Capetown, South Africa, June 2014. PMID:24995473

Hyde, T.P.; Craddock, H.L.; Gray, J.C.; Pavitt, S.H.; Hulme, C.; Godfrey, M.; Fernandez, C.; Navarro-Coy, N.; Dillon, S.; Wright, J.; Brown, S.; Dukanovic, G.; Brunton, P.A.

2014-01-01

175

Microbial contamination of contact lens storage cases and domestic tap water of contact lens wearers.  

PubMed

Contact lenses have been widely used as an alternative to spectacles both in developed and developing countries. However, under certain circumstances, adverse responses can occur during contact lens wear and several microorganisms--including bacteria, fungi, and free living amoebae--can cause several eye infections in wearers. Extended wear of contact lenses is the major risk factor of eye infections such as microbial keratitis, besides contaminated contact lens storage case, contaminated lens care solutions, and inaccurate contact lens handling. In this study, we collected contact lens storage case and domestic tap water samples from 50 asymptomatic contact lens wearers. We determined that total aerobic mesophilic bacteria were isolated in 45 (90 %), Gram negative rod bacteria were isolated in 20 (40 %), Pseudomonas spp. were isolated in 2 (4 %) and fungi were isolated in 18 (36 %) out of 50 contact lens storage cases. Free living amoebae were not detected in investigated contact lens storage cases. At the same time, out of 50, total aerobic mesophilic bacteria were isolated in 34 (68 %), fungi were isolated in 15 (30 %) and free living amoebae were isolated in 15 (30 %) domestic tap water samples. No Gram-negative rod bacteria and Pseudomonas spp. were detected in investigated water samples. Two contact lens case samples and two tap water samples were excluded from the analysis for Pseudomonas spp. for technical reasons. According to our findings, inadequate contact lens maintenance during lens wear may result in the contamination of contact lens storage cases. This situation can lead to severe eye infections in contact lens wearers over time. PMID:23064864

Üstüntürk, Miray; Zeybek, Zuhal

2012-11-01

176

Acanthamoeba species Keratitis in a Soft Contact Lens Wearer Molecularly Linked to Well Water  

PubMed Central

Acanthamoeba species keratitis has been associated with soft contact lens wear. In the present report, an epidemiological link was established between the patient’s isolate and well water from the home using molecular methods. To the authors’ knowledge, this is the first case in Canada where such a link has been established. Primary care practitioners and specialists, including ophthalmologists and infectious diseases specialists, must maintain a high degree of clinical suspicion in soft contact lens wearers with keratitis unresponsive to conventional topical and systemic treatment. PMID:18418487

Mubareka, Samira; Alfa, Michelle; Harding, Godfrey K; Booton, Gregory; Ekins, Marilyn; VanCaeseele, Paul

2006-01-01

177

Use of a digitally planned and fabricated mandibular complete denture for easy conversion to an immediately loaded provisional fixed complete denture. Part 1. Planning and surgical phase.  

PubMed

This article describes a unique prosthetically driven protocol that uses computeraided engineering to develop sophisticated, scientific algorithms that guide the fabrication of a conversion denture using the AvaDent Digital Denture system (Global Dental Science). This system is combined with Nobel Clinician (Nobel Biocare) implant-planning software to optimize accuracy and to make it easier and faster to convert a denture to an immediately loaded provisional implant supported fixed complete denture following implant placement, using a NobelGuide surgical template. PMID:25191881

Lozada, Jaime L; Garbacea, Antoanela; Goodacre, Charles J; Kattadiyil, Mathew T

2014-01-01

178

A comparison of the fitting accuracy of thermoplastic denture base resins used in non-metal clasp dentures to a conventional heat-cured acrylic resin.  

PubMed

Abstract Objective. To incorporate a metal framework into removable partial dentures, the dimensional accuracy of thermoplastic resins requires precision equivalent to conventional acrylic resins. This study aimed to evaluate the fitting accuracy of thermoplastic resins compared to heat-cured acrylic resin. Materials and methods. Four thermoplastic resins (polyethylene terephthalate [EstheShot, ES; EstheShot Bright, ES-B], polyamide [Lucitone FRS, LF], polycarbonate [Reigning Resin N, RN] and a heat-curing acrylic resin [Acron, AC]) were used. The specimens were created on master casts constructed of high-strength stone that simulated a maxillary edentulous ridge. Additionally, high-expansion stone was used as the master cast for RN specimens. The ES-B, LF and RN specimens were prepared with and without annealing after injection molding. The gaps between the molded resin and the cast were measured. Results. ES had the smallest gap and was significantly smaller than AC (p < 0.05). The gap sizes of ES-B, LF and RN (high-expansion stone) without annealing were similar to AC (p > 0.05), while the gap size of RN (high-strength stone) with and without annealing was significantly greater than AC (p < 0.001). The gap sizes of ES-B and LF with annealing were significantly less than AC (p < 0.05). Further, the gap sizes of ES-B, LF and RN with annealing were significantly smaller than the gaps without annealing (p < 0.05). Conclusions. The results suggested that ES, ES-B and LF have adequate fitting accuracy for incorporating metal framework into dentures and that annealing effectively improved the fitting accuracy of ES-B, LF and RN. PMID:25314120

Wada, Junichiro; Fueki, Kenji; Yatabe, Masaru; Takahashi, Hidekazu; Wakabayashi, Noriyuki

2015-01-01

179

Comparative Evaluation of Sorption, Solubility and Microhardness of Heat Cure Polymethylmethacrylate Denture Base Resin & Flexible Denture Base Resin  

PubMed Central

Aim: The aim of the study was to evaluate and compare sorption, solubility and microhardness of heat cure polymethylmethacrylate (PMMA) denture base resin and flexible (thermoplastic polyamide nylon) denture base resin. Materials and Methods: Sorption, solubility and microhardness were assessed to determine compliance with ADA Specification no. 12. Results were assessed using statistical and observational analyses. Result: All materials satisfied ADA requirements for sorption, solubility and microhardness. Heat cure PMMA showed more sorption, solubility and microhardness than flexible (thermoplastic polyamide nylon). Conclusion: Flexible (thermoplastic polyamide nylon) resin absorbs less water, is less soluble and is more flexible than PMMA. PMID:25302291

Bulbule, Nilesh; Kulkarni, Shilpa; Shah, Riddhi; Kakade, Dilip

2014-01-01

180

Bacteria and parasites in contact lenses of asymptomatic wearers in Nigeria  

PubMed Central

Purpose This is to determine the prevalence of bacterial and parasitic flora in asymptomatic disposable and extended contact lens wearers in Lagos State, Nigeria. Methods The study was carried out on 156 contact lenses from 78 asymptomatic wearers between the ages of 12 to 38 years. Eighty two disposable daily wear (DWCL) and 74 extended wear (EWCL) contact lenses were examined. The contact lenses’ swabs and the trays were transferred to the laboratory for microbial examination. Results Fifty two (70.27 %) extended wear contact lenses and 50 (60.98 %) disposable contact lenses examined were contaminated. Streptococcus spp. (4.23 %) were found in extended contact lenses and (3.9 %) in disposable contact lenses. Escherichia coli (15.49 %) were more in the extended contact lenses and were in higher proportion (14.74 %) than the other microorganisms in all the contact lenses. Klebsiella spp. (12.99 %) were more in the disposable lenses than in the extended wear lenses (12.69 %). there were more disposable lenses (41.56 %) with ‘no growth’. Amoebae were isolated from (6.49 %) disposable and (4.23 %) extended wear contact lenses. Seventeen (32.69 %) DWCL had mixed flora. There were significant differences between disposable and extended contact lenses, p < 0.05. Conclusions EWCL present more microorganisms and pose threat to the users. DWCL had more amoebae, which calls for suitable lens care methods. Further studies may be needed to determine the level of care required for contact lens users in developing countries.

Emina, Michael Osita; Idu, Faustina Kemdinum

2011-01-01

181

Clinical and microbial evaluation of treatment regimens to reduce denture stomatitis.  

PubMed

This study evaluated the effect of an antimicrobial mouthrinse, denture soft relines, and a placebo rinse on the clinical findings and microbial flora of 78 patients with denture stomatitis. For 28 days the study and control groups performed oral rinses and denture soaks. Reline group patients had maxillary denture soft relines that were changed every 7 days. At the end of the study, the mean severity of denture stomatitis was significantly less in the groups that used the study rinse (P less than 0.01) and received denture relines (P less than 0.05) compared to the control. Analysis of variance revealed significant differences in ranked adjusted percentage counts in two out of 13 denture plaque organisms investigated (Fusobacterium nucleatum [P less than 0.05] and total Bacteroides [P less than 0.05]), with the antiseptic rinse producing the lowest count. Yeast populations were reduced, but not significantly (P = 0.07). In the absence of other mechanical denture hygiene procedures, the antiseptic rinse and relines were equally effective in reducing denture stomatitis and potential pathogens of denture plaque flora. PMID:2088373

DePaola, L G; Minah, G E; Elias, S A; Eastwood, G W; Walters, R A

1990-01-01

182

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2012 CFR

...b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the patient applies to the...the OTC denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the intended use of the...

2012-04-01

183

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2011 CFR

...b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the patient applies to the...the OTC denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the intended use of the...

2011-04-01

184

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2010 CFR

...b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the patient applies to the...the OTC denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the intended use of the...

2010-04-01

185

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2013 CFR

...b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the patient applies to the...the OTC denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the intended use of the...

2013-04-01

186

21 CFR 872.3540 - OTC denture cushion or pad.  

Code of Federal Regulations, 2014 CFR

...b) Classification. (1) Class I if the device is made of wax-impregnated cotton cloth that the patient applies to the...the OTC denture cushion or pad is made of a material other than wax-impregnated cotton cloth or if the intended use of the...

2014-04-01

187

Shear bond strength of microwaveable acrylic resin for denture repair.  

PubMed

Microwaveable acrylic denture resins are believed to provide an effective means of repairing fractured dentures. This in vitro investigation compared the bond strength of a microwaveable acrylic resin as a denture repair material to two established auto-polymerized resins. Fifty-one specimens were made using Lucitone 199 as a simulated denture base, and were then divided into three groups of 17 samples each. Each test group was bonded with the following acrylic resins: Acron Mc, Rapid Repair and Palapress. A shear bond strength test was carried out 24 h after the samples were bonded. Fracture analysis showed that bond failure was adhesive for all groups. Shear bond values showed a statistically significant difference at P < 0.05 level between Acron Mc and Rapid Repair; Palapress and Rapid Repair, and indicated that Acron Mc and Palapress were superior to Rapid Repair as a repair material. However, there was no statistical difference found between Acron Mc and Palapress. Microwaveable acrylic resins produce repaired junctions of adequate strength. PMID:15265217

Ng, E T L; Tan, L H H; Chew, B S H; Thean, H P Y

2004-08-01

188

Computerized cephalometric evaluation of changes following treatment with complete dentures.  

PubMed

The aim of this study was to provide longitudinal evaluation of the changes after complete dentures therapy and the rate of residual ridge resorption through a six-year period of denture wearing. The authors presented the case of a 76-year-old patient, edentulous for twelve years, wearing complete dentures for six years, with the eugnat jaw relationship. Cephalometric radiograph was carried out in the process of new complete denture production, while the evaluation was carried out after six years. Cephalometric analysis was performed by using "Dr. Ceph" computer software (FYI Technologies, GA, USA). After six years, the reduction of anterior total facial height was 5.5 mm and the anterior lower facial height was 5.5 mm, the vertical residual ridge reduction of the maxilla was 1.4 mm and the reduction of the mandible was 3mm. The study confirms the reliability and advantages of cephalometric analyses and reveals their application possibilities in prosthetic diagnostics and therapy, as well as in evaluation of rehabilitative results in edentulous patients and longitudinal analysis of changes on the orofacial complex tissues and intemaxillary relationships. PMID:22788068

Strajni?, Ljiljana; Miskovi?, Branka

2012-01-01

189

Cytotoxicity of four denture adhesives on human gingival fibroblast cells.  

PubMed

Abstract Objective. The purpose of this study was to compare the cytotoxicity of four denture adhesives on human gingival fibroblast cells. Materials and methods. Immortalized human gingival fibroblasts were cultured with one of four different denture adhesives, Polident, Protefix, Staydent or Denfix-A, which was placed in insert dishes (10% w/v concentration) for 48 h. The MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay and flow cytometric apoptosis assay were used to evaluate cell viability and apoptosis rates. The fibroblasts were also examined under a scanning electron microscope. Results. The MTT assay showed that all denture adhesives resulted in a significantly lower cell viability compared to the control cells propagated in normal culture medium (p < 0.05), with Staydent demonstrating the lowest cell viability. According to the flow cytometric apoptosis assay, Staydent and Protefix showed significantly higher apoptosis rates than the control group (p < 0.05), whereas Polident and Denfix-A did not demonstrate any significant differences (p > 0.05). Staydent showed the highest apoptosis rate. Scanning electron microscopy showed that the cells of the Staydent group underwent cytoplasmic membrane shrinkage, with cell free areas containing residual fragments of the membrane of dead cells. Conclusions. The four denture adhesives evaluated in this study imparted cytotoxic effects on human gingival fibroblast cells. Staydent showed the highest toxicity. PMID:25220520

Lee, Yoon; Ahn, Jin-Soo; Yi, Young-Ah; Chung, Shin-Hye; Yoo, Yeon-Jee; Ju, Sung-Won; Hwang, Ji-Yun; Seo, Deog-Gyu

2015-02-01

190

1 Lotion strengths on wearers of bathing 8D 5 Big interview for a reporter for 19A  

E-print Network

'25D 32 Chip dip at a 14A 34 Students seeking these degrees may have to draw a model on a 22A (abbr in a series of 2003 articles in 19A 54 1943 event involving wearers of 55D 8D 55 Popular clothing items

Krebs, Mike

191

Objective evaluation of the quality of the retinal image in contact lens wearers  

NASA Astrophysics Data System (ADS)

A double-pass method is applied to determine the optical image quality in contact lens (CLs) wearers. This is an objective optical non-invasive technique that permits us to test 'in vivo' the optical performance of CLs wearing eyes. The retinal image quality was measured for three subjects wearing two types of monofocal CLs. The results show the effectiveness of the technique to determine the optical performance of the CL and the CL-eye system. The importance of the ocular astigmatism on the MTF is also discussed. In eyes presenting corneal astigmatism, the best results are obtained when wearing RGP CLs. When the astigmatism is corrected, slightly better results were obtained with RGP lenses.

Pujol, Jaume; Torrents, Aurora G.; Gispets, J.

1996-01-01

192

First Report of Hartmannella keratitis in a Cosmetic Soft Contact Lens Wearer in Iran  

PubMed Central

Background Poor hygiene will provide good condition for corneal infections by opportunistic free-living amoebae (FLA) in soft contact lens wearers. In the present study an amoebic keratitis due to Hartmannella has been recognized in a 22-year-old girl with a history of improper soft contact lens use. She had unilateral keratitis on her left eye. Her clinical signs were eye pain, redness, blurred vision and photophobia. The round cysts of free-living amoebae were identified in non-nutrient agar medium by light microscopy. These cysts were suspected to be Hartmannella using morphological criteria. A PCR assay has been confirmed that the round cysts were belonged to H. vermiformis. PMID:24454444

ABEDKHOJASTEH, Hoda; NIYYATI, Maryam; RAHIMI, Firoozeh; HEIDARI, Mansour; FARNIA, Shohreh; REZAEIAN, Mostafa

2013-01-01

193

Water sorption by maxillary acrylic resin denture base and consequent changes in vertical dimension.  

PubMed

Many kinds of materials have been tried in the Laboratory and to some extent clinically prior to introduction of acrylic resin. With the introduction of acrylic resin as denture base material, continuous attempts have been made to evaluate its physical properties. To observe the changes in vertical measurements of acrylic resin dentures due to water sorption and to assess variations of vertical movements of individual teeth within dentures due to water sorption; present study was carried out on 25 maxillary acrylic dentures. From results, the maximum water sorption appears to take place within 24 hours and after 28 day of water sorption; there is no change in vertical dimension if the denture is placed for further more time. With the introduction of acrylic resin as denture base material continued attempts have been made to evaluate physical properties so as to determine its suitability as an ideal nonmetalic denture base materials. Several investigations have been carried out on physical properties of this material such as compressive strength, tensile strength, solubility and colour stability. These have proved their superiority over other nonmetalic denture base materials used so far. Also several studies have been carried out to assess dimensional changes that occur in acrylic resin during processing, but very few studies have been carried out about the water sorption changes in the acrylic resin and still few about the vertical dimensional changes in acrylic resin due to water sorption. While fabricating the denture base from the acrylic resin, it comes in contact with water during polishing as well as cleaning, consequently during the use of denture it is constantly wetted by oral fluids. It is the hypothesis that water sorption by denture base acrylic may effect the retention and stability of the denture. It has been shown that water molecules act according to the laws of diffusion. The diffusion presumably occurs between the macromolecules which are forced slightly apart. This separation renders the molecules mobile and the inherent stresses created during heat curing of the acrylic resin can be relieved with consequent intermolecular relaxation and possible changes in the shape of the denture. Exposure time also plays a significant role in water sorption. The present investigation was therefore, carried out by keeping the following objectives: (1) The primary objective was to observe the changes in vertical measurements of acrylic resin dentures due to water sorption. (2) To assess the variations of vertical movement of individual teeth within the dentures due to water sorption. PMID:9791250

Joshi, N P; Sanghvi, S J

1994-09-01

194

The effect of retention grooves in acrylic resin teeth on tooth denture-base bond.  

PubMed

A progressive shear compressive load was applied at an angle to the lingual surface of acrylic resin teeth bonded to denture base acrylic resin. No statistically significant advantage was derived by preparing retention grooves of different shapes in the ridge lap surface of the denture teeth. PMID:3514898

Cardash, H S; Liberman, R; Helft, M

1986-04-01

195

Introduction of a denture injection system for use with microwaveable acrylic resins.  

PubMed

Recently, an injection system for use with microwaveable denture base resins was introduced. Preliminary evaluation of this system was performed a university-based dental laboratory. This article provides a description of the complete denture fabrication technique, as well as observations regarding its design and practicality. PMID:9563329

Phoenix, R D

1997-12-01

196

Aerobic bacteria in the oral cavity of patients with removable dentures  

Microsoft Academic Search

Purpose: Determination of bacterial composition in the oral cavity of patients with removable dentures and with own dentition (without dentures). Material and methods: Bacteriological investigations were performed in 55 patients from the department of inter- nal medicine (32 diabetic patients) and 40 patients treated in surgical department (25 patients with malignancy). Pal- ate mucosa and tongue dorsa swabs were collected

Daniluk T; Fiedoruk K; Cylwik-Rokicka D; Tokajuk G; Stokowska W

2006-01-01

197

Cytological response of palatal epithelium to TiN-coated CoCr alloy denture.  

PubMed

The aim of this study was to assess the impact of titanium nitride coatings on CoCr alloy metal parts in framework dentures on human palatal epithelium cytology compared to framework dentures made with the same alloy but without titanium nitride coating, and to acrylic dentures. Every prosthetic restoration introduced into the oral cavity and remaining in direct contact with the palate exhibits a varied and harmful effect on the state of the palatal epithelium by disturbing its keratinization. CoCr alloy dentures produce a significantly greater perturbation of keratinization compared to acrylic dentures. There is no evidence showing that a titanium nitride coating of the CoCr alloy plays a protective role in the environment of the oral cavity. PMID:22532144

Lukomska-Szyma?ska, Monika; Brzezi?ski, Piotr M; Zieli?ski, Andrzej; Soko?owski, Jerzy

2012-01-01

198

A comparative analysis of the effect of three types of denture adhesives on the retention of maxillary denture bases: an in vivo study.  

PubMed

There are many factors involved in the success of a good quality complete dentures, one of them is retention. There are some forcing situations where providing optimal retention may be a problem, in which use of denture adhesives is recommended. In the present study, primary and secondary impressions were made on 20 completely edentulous patients, master cast was fabricated. Master cast was duplicated; heat-cured denture base was fabricated. The retention test for control group, powder group, wafer group, paste group was done using a customized force sensor device. Readings was subjected to ANOVA followed by post hoc test. Results show that the retention force value of the paste group was the maximum, followed by powder group, wafer group and the least retention force value was observed with control group. Within the limitations of the study it can be concluded that the paste form of denture adhesive has the best retentive property compared to the powder and wafer. PMID:25489160

Pachore, Nivedita J; Patel, J R; Sethuraman, Rajesh; Naveen, Y G

2014-12-01

199

Tensile and shear bond strength of hard and soft denture relining materials to the conventional heat cured acrylic denture base resin: An In-vitro study  

PubMed Central

Background: The condition of the denture bearing tissues may be adversely affected by high stress concentration during function. Chairside Denture (Hard and Soft) reliners are used to distribute forces applied to soft tissues during function. Tensile and shear bond strength has been shown to be dependent on their chemical composition. A weak bond could harbor bacteria, promote staining and delamination of the lining material. To investigate tensile and shear bond strength of 4 different commercially available denture relining materials to conventional heat cured acrylic denture base resin. Materials & Methods: 4 mm sections in the middle of 160 Acrylic cylindrical specimens (20 mm x 8 mm) were removed, packed with test materials (Mollosil, G C Reline Soft, G C Reline Hard (Kooliner) and Ufi Gel Hard and polymerized. Specimens were divided into 8 groups of 20 each. Tensile and shear bond strength to the conventional heat cured acrylic denture base resin were examined by Instron Universal Tensile Testing Machine using the equation F=N/A (F-maximum force exerted on the specimen (Newton) and A-bonding area= 50.24 mm2). One-way ANOVA was used for multiple group comparisons followed by Bonferroni Test and Hsu’s MCB for multiple pairwise comparisons to asses any significant differences between the groups. Results: The highest mean Tensile bond strength value was obtained for Ufi Gel Hard (6.49+0.08 MPa) and lowest for G C Reline Soft (0.52+0.01 MPa). The highest mean Shear bond strength value was obtained for Ufi Gel Hard (16.19+0.1 MPa) and lowest for Mollosil (0.59+0.05 MPa). The Benferroni test showed a significant difference in the mean tensile bond strength and the mean shear bond strength when the two denture soft liners were compared as well as when the two denture hard liners were compared. Hsu’s MCB implied that Ufi gel hard is better than its other closest competitors. Conclusion: The Tensile and Shear bond strength values of denture soft reliners were significantly lower than denture hard reliners. How to cite the article: Lau M, Amarnath GS, Muddugangadhar BC, Swetha MU, Das KA. Tensile and shear bond strength of hard and soft denture relining materials to the conventional heat cured acrylic denture base resin: An In-vitro study. J Int Oral Health 2014;6(2):55-61. PMID:24876703

Lau, Mayank; Amarnath, G S; Muddugangadhar, B C; Swetha, M U; Das, Kopal Anshuraj Ashok Kumar

2014-01-01

200

Evaluation of adhesive properties of three resilient denture liners by the modified peel test method.  

PubMed

The characteristics of adhesive properties between a denture base and resilient denture liner were investigated by a modified peel test with an L-shaped metal attachment. Three commercially resilient denture lining materials, namely GC Reline Soft (S), GC Reline Extra Soft (ES), and GC Reline Ultra Soft (US), were evaluated. Acrylic resin (GC Acron) was used as denture base material. Peel specimens consisting of the denture base acrylic resin and resilient denture liner were tested after storage for 1 and 30 days in distilled water at 37 degrees C. The modified peel test method gave load-displacement curves and work of adhesion (W(A)) values of the denture base material and resilient denture liner. The W(A) of specimens after 1 day of storage ranged from 1.71 to 2.55 N mm(-1) and increased in the order from US to S to ES. On the other hand, the W(A) of specimens after 30 day of storage ranged from 1.44 to 2.47 N mm(-1) and increased in the order from US to ES to S. US had significantly lower W(A) after 1 and 30 days of storage than did S and ES (P<0.05). Comparison of the W(A) between 1 and 30 days, reveals large differences for ES and US, but not for S. This could be explained by the difference in failure modes. Within the limitations of this investigation, it was concluded the modified peel test is effective for evaluating the adhesion between denture base material and a resilient denture liner. PMID:18829404

Tanimoto, Yasuhiro; Saeki, Hiroyuki; Kimoto, Suguru; Nishiwaki, Tsuyoshi; Nishiyama, Norihiro

2009-02-01

201

Microwave polymerization of denture base materials. A comparative study.  

PubMed

A comparison of some properties of denture base polymers processed by both microwave and water-bath methods demonstrated that, in general, water-bath polymerization with a long curing cycle and a 3-h terminal boil produced superior properties. Although these two methods were inter-changeable for the conventionally heat cured material, consistently superior results were produced by following the method recommended by the manufacturer. Microwaving of autopolymerizing resin improved mechanical properties and reduced residual monomer. The clinical significance of these results remains to be tested. PMID:10564437

Blagojevic, V; Murphy, V M

1999-10-01

202

Bonding auto-polymerising acrylic resin to acrylic denture teeth.  

PubMed

This study investigated the effect of surface treatments on the shear bond strength of an auto-polymerising acrylic resin cured to acrylic denture teeth. The surface treatments included a combination of grit-blasting and/or wetting the surface with monomer. Samples were prepared and then stored in water prior to shear testing. The results indicated that the application of monomer to the surface prior to bonding did not influence the bond strength. Grit blasting was found to significantly increase the bond strength. PMID:19839190

Nagle, Susan; Ray, Noel J; Burke, Francis M; Gorman, Catherine M

2009-09-01

203

Impacts of wearing complete dentures on bolus transport during feeding in elderly edentulous.  

PubMed

Prosthetic treatment with dentures is often required for the elderly who have reduced swallowing function. Therefore, it is important to understand the relationship between denture-wearing and feeding function from the perspective of swallowing. To clarify changes in bolus transport during feeding in elderly edentulous patients with or without complete dentures. Subjects were 15 elderly edentulous volunteers who were treated with maxillary and mandibular complete dentures. The test food was 10 g of minced agar jelly containing barium sulphate with a particle diameter of 4·0-5·6 mm. Lateral videofluoroscopy was performed to assess the position of the leading edge of the bolus, the bolus volume in each area at swallow onset, bolus transit time and the mandibular position during pharyngeal swallowing. There were significant changes between the bolus transport with and without dentures. Without dentures, the leading edge of the bolus at swallow onset fell from the valleculae area to the hypopharynx, and the bolus volume in the hypopharynx increased. Bolus transit time increased in the oral cavity, valleculae and hypopharynx. The mandibular position shifted anterosuperior direction. The results arose owing to anatomical changes in the oral and pharyngeal structure and the following functional changes: poor food manipulation, poor bolus formation and delayed swallowing reflex. Removing dentures in elderly edentulous individuals influences bolus transport during feeding, resulting in the exacerbation of the reduced swallowing reserve capacity that accompanies ageing, and may increase the risk of dysphagia. PMID:24237359

Yamamoto, H; Furuya, J; Tamada, Y; Kondo, H

2013-12-01

204

Effect of chewing on dental patients with total denture: an experimental study.  

PubMed

In this study, we have explored the prospect of assessing and following level of total denture adaptation by use of EMG signals recorded during gum chewing. Total of 14 edentulous patients, 6 women and 8 men, with an average age of 63±9 years, were recruited. Separate EMG recordings were obtained from left and right temporalis and masseter muscles of the patients for a period of 10 seconds, while they were chewing a sugar-free gum on their left and right sides. EMG recordings were repeated at three times: before, right after, and six months after the placement of the denture. We have tried to standardize environmental and individual factors during EMG recordings. The EMG data have been pre-processed and analyzed using Discrete Wavelet Transform (DWT) and obtained features were statistically evaluated using the paired sample t-test. Chewing activity on the right and left side is analyzed by making comparisons of muscle activity between before and right-after cases and before and six-months-after denture fixation cases. A comparison between right and left side mastication is also made at different time points. We have suggested and implemented a new test and comparison procedure in order to assess adaptation to denture fixation using EMG analysis. In this study, the results indicate that DWT based EMG analysis is instrumental in evaluating denture adaptation and as time progresses the adaptation to denture and hence chewing efficiency increases in patients with total denture replacement. PMID:23504412

Tokmakci, Mahmut; Zortuk, Mustafa; Asyali, Musa Hakan; Sisman, Yildiray; Kilinc, Halil Ibrahim; Ertas, Elif Tarim

2013-12-01

205

The tooth-denture base bond: stress analysis using the finite element method.  

PubMed

Although acrylic resin teeth are the most popular artificial teeth used for denture construction, a high number fracture away at the tooth-denture base interface. Various causes have been documented for this failure; however, it is logical that eventual fracture occurs due to localised tensile stresses at this interface. Examination of these stresses using the finite element method showed that on load application to the upper incisors, the maximum tensile stresses were concentrated within the body of the tooth and not at the tooth-denture base interface. Stresses encountered at the interface were relatively low and introduction of a crack made no significant difference to their magnitude. PMID:8148790

Darbar, U R; Huggett, R; Harrison, A; Williams, K

1993-03-01

206

Creep and stress relaxation behavior of two soft denture liners.  

PubMed

Numerous investigators stated the indications of soft denture lining materials; but no one determined the indications of these materials according to their chemical structure. The purpose of this investigation was to evaluate the viscoelastic properties of acrylic and silicon lining materials. This study investigated and compared viscoelastic properties of two resilient denture lining materials. Tested materials were laboratory processed; one of them was silicone-based liner product (Molloplast-B), and the other was plasticized acrylic resin (Vertex™ Soft). Twenty cylindrical specimens (10-20 mm in length, 11.55 mm in diameter) were fabricated in an aluminum mold from each material for creep and stress relaxation testing (the study of viscoelastic properties). Tests were performed by using the universal testing machine DY-34. Collected data were analyzed with t test statistics for statistically significant differences at the 95 % confidence level. There was a clear difference in creep and stress relaxation behavior between acrylic and silicone liners. Statistical study of Young's moduli illustrated that Vertex™ Soft was softer than Molloplast-B. On the other hand, the results explained that the recovery of silicone material was better than of acrylic one. The creep test revealed that the plasticized acrylic resin lining material exhibited considerable creep, whereas silicone-based liner exhibited elastic behavior. Besides, the stress relaxation test showed that relaxation of the plasticized acrylic resin material was bigger than of the silicone-based liner. PMID:24605004

Salloum, Alaa'a M

2014-03-01

207

Dynamic viscoelastic properties of vinyl polysiloxane denture soft lining materials.  

PubMed

The aim of this study was to investigate the dynamic viscoelastic properties of seven commercially available vinyl polysiloxane denture soft lining materials. Five rectangular specimens (2 x 10 x 30 mm) were prepared from each material. The complex modulus E* (MPa) and loss tangent (tan delta) of each specimen were determined with a non-resonance forced vibration method using an automatic dynamic viscoelastometer at 1 Hz after 1 day of dry storage, and after 1, 30, 60, 90 and 180 days of wet storage at 37 degrees C. All data were analysed using one-way anova and Bonferroni/Dunn's test for multiple comparisons with a significance level of P < 0.01. All materials varied widely in terms of viscoelasticities and showed both an increase in E* and a decrease in tan delta at 1 Hz after the 1-day wet storage. After 60 days of wet storage, both E* and tan delta did not change significantly. The stiffer materials (>30% filler content) with high E* values (>2.00 MPa) showed elastic behaviour with tan delta values of around 0.03. The softer materials (6% filler content) with high tan delta values (initial value > 0.10) showed viscous behaviour and were easily affected by water absorption after the 1-day wet storage. It can be concluded that for the proper selection of vinyl polysiloxane denture soft lining materials, it is very important to evaluate the viscoelastic properties after 60 days of wet storage. PMID:19840358

Abe, Y; Taji, T; Hiasa, K; Tsuga, K; Akagawa, Y

2009-12-01

208

Long-term follow-up of conical crown-retained dentures fabricated using different technologies.  

PubMed

This study presents the results of a long-term clinical evaluation of conical crown-retained dentures fabricated using different technologies. Four different material connections between the outer and inner crowns were used: cast gold/cast gold, cast gold/electroforming, nonprecious alloy/electroforming, and titanium abutment/electroforming. Technical failures and retention values were assessed. The best clinical outcome was found with dentures in which both crowns were cast from gold alloy. The most frequent technical failures were observed in restorations with electroformed outer crowns. Better clinical outcomes were noted when the electroformed outer crowns were used in dentures retained by implants as compared to dentures on natural dentition. PMID:22577653

Pietruski, Jan K; Pietruska, Malgorzata D; Sajewicz, Eugeniusz

2012-08-01

209

[Polyurethane denture base material "Pentalur" and modified polyurethane compositions: comparative study of mechanical properties].  

PubMed

Results of laboratory tests of polyurethane based material "Pentalur" conducted to determine its mechanical properties proved the material to meet basic requirements for removable dentures materials. The introduction of simple poluethers with certain molecular weight as well as 1,4-butanediol allows varying polyurethane properties in a fairly wide range. This range of polyurethane mechanical properties along with good biocompatibility opens new possibilities in creation of removable dentures with improved functional properties as well as maxillofacial prosthesis. PMID:23528393

Al'ter, Iu M; Tkachuk, A-M P; Poiurovskaia, I Ia; Sutugina, T F; Ogorodnikov, M Iu

2013-01-01

210

Peel strength of denture liner to PMMA and polyamide: laser versus air-abrasion  

PubMed Central

PURPOSE This study investigated the effect of laser parameters and air-abrasion on the peel strength of silicon-based soft denture liner to different denture resins. MATERIALS AND METHODS Specimens (N=180) were prepared out of three different denture base resins (Rodex, cross-linked denture base acrylic resin; Paladent, heat-cured acrylic resin; Deflex, Polyamide resin) (75 mm × 25 mm × 3 mm). A silicon-based soft denture liner (Molloplast B) was applied to the denture resins after the following conditioning methods: a) Air-abrasion (50 µm), b) Er,Cr:YSGG laser (Waterlase MD Turbo, Biolase Technology) at 2 W-20 Hz, c) Er,Cr:YSGG laser at 2 W-30 Hz, d) Er,Cr:YSGG laser at 3 W-20 Hz, e) Er,Cr:YSGG laser at 3 W-30 Hz. Non-conditioned group acted as the control group. Peel test was performed in a universal testing machine. Failure modes were evaluated visually. Data were analyzed using two-way ANOVA and Tukey's test (?=.05). RESULTS Denture liner tested showed increased peel strength after laser treatment with different parameters (3.9±0.4 - 5.58±0.6 MPa) compared to the control (3.64±0.5 - 4.58±0.5 MPa) and air-abraded groups (3.1±0.6 - 4.46±0.3 MPa), but the results were not statistically significant except for Paladent, with the pretreatment of Er,Cr:YSGG laser at 3 W-20 Hz. Polyamide resin after air-abrasion showed significantly lower peel strength than those of other groups (3.1±0.6 MPa). CONCLUSION Heat-cured acrylic resin, PMMA, may benefit from Er,Cr:YSGG laser treatment at 3 W-20 Hz irradiation. Air-abrasion of polyamide resins should be avoided not to impair their peel bond strengths to silicon-based soft denture liners. PMID:24049570

Bagis, Bora; Özcan, Mutlu; Durkan, Rukiye; Turgut, Sedanur; Ates, Sabit Melih

2013-01-01

211

Factors affecting wear of composite resin denture teeth--24-month results from a clinical study.  

PubMed

The objectives of this study were to measure the occlusal wear of composite resin denture teeth in patients wearing a complete denture and to evaluate factors affecting wear. Fifty participants provided with complete dentures in at least one jaw were included. Gypsum casts were made from preliminary vinyl polysiloxane impressions 4 weeks after insertion, then after 6 (t(1)), 12 (t(2)), and 24 months (t(3)). Three-hundred and three posterior denture teeth were evaluated after 24 months. Wear was measured indirectly, from the casts, by means of a three-dimensional laser scanner device. Sequential images of the occlusal surfaces were digitized and superimposed (occlusal matching). Statistical analysis was performed by the use of mixed regression models, with the patient being a random effect. Mean wear (median, interquartile range; micrometer) of the entire occlusal surface was 8 (19) at t(1), 18 (34) at t(2), and 40 (61) at t(3). Maximum vertical loss (median, interquartile range; micrometer) was 92 (112) at t(1), 146 (148) at t(2), and 226 (184) at t(3). The dental status of the opposing jaw and the nature of the opposing material significantly affected the wear of denture teeth at t (3). Gender, daily wearing time, jaw, and type of tooth had no significant effects on the extent of wear. Clinically relevant vertical loss of composite resin denture teeth occurs after 24 months. Considering the limitations of this study, wear of denture teeth was affected by dental status and opposing material. The results suggest that wear of composite resin denture teeth exceeds that of enamel. PMID:21384126

Stober, Thomas; Geiger, Andreas; Rues, Stefan; Dreyhaupt, Jens; Rammelsberg, Peter; Ohlmann, Brigitte

2012-04-01

212

A histomorphometric analysis on bone dynamics in denture supporting tissue under continuous pressure.  

PubMed

The purpose of this study was to investigate bone dynamics under a denture base, in relation to the intensity of continuous pressure exerted through it to the denture supporting tissue. Two hundred and fifty male rats of Wistar strain were divided into five groups, four of which wore experimental dentures to load continuous pressure of 0.0, 1.0, 10.0 or 20.0 kPa to the molar region of the hard palate. The fifth group was the non-denture-wearing group. Fluorescent labelled palatal bone tissue was stained with Villanueva bone stain and was prepared for the undecalcified grinding section. In the 0.0 kPa group whose mucosa was covered with denture base, although no bone resorption was observed, bone formation was inhibited up to 4 weeks after the denture insertion. Bone dynamics in the 1.0 kPa group was similar to those in the 0.0 kPa group. In the 10.0 and 20.0 kPa groups, bone resorption was observed until 3 and 2 weeks after the denture insertion, and the amount of bone resorption (AoBR) was 24 +/- 17 and 35 +/- 21 lm, respectively. After bone resorption in these groups, although osteoid formation increased earlier than 0.0 kPa group, mineralization showed a similar time course with 0.0 kPa group. In conclusion, bone dynamics under a denture base caused by continuous pressure exerted through it was revealed to show a time course depending on the intensity of the initial pressure. Amount of bone resorption was also revealed to correspond to the intensity of the initial pressure. Bone formation following bone resorption did not cause equivalent recovery of the bone surface level to the level observed in the case without bone resorption. PMID:11844035

Imai, Y; Sato, T; Mori, S; Okamoto, M

2002-01-01

213

Finite Element Analysis of Soft-lined Mandibular Complete Denture and its Supporting Structures  

PubMed Central

Background and aims There are many edentulous people with severely resorbed residual ridges and non-resilient lin-ing mucosa that are unable to tolerate occlusal forces during functional and parafunctional movements. Lining the tissue surface of dentures with a flexible material can theoretically distribute and absorb forces with cushioning effect. The aim of this study was to evaluate the effect of a soft liner on stress levels in mandibular complete denture and its supporting struc-tures by finite element analysis. Materials and methods A simplified 3-dimensional finite element model of relatively resorbed mandible, mucosa, denture and a soft liner was prepared. Then the model, with and without soft liner, underwent normal vertical and lateral occlusal forces. The stresses were analyzed using the ANSYS 12 software. Results Using the soft liner increased stress levels up to 18.5% and 30% in the cortical bone and mucosa, respectively, after vertical load was applied in the incisor region. Application of bilateral vertical load on the molar area increased stress in cortical bone u to 44% and in the mucosa up to 29%. Unilateral loading in the canine area increased stress level in the mucosa up to 63.5%. The highest stress was seen at denture base followed by the cortical bone. Conclusion Use of soft liners increased stress in denture supporting structures. Higher level of stress concentration was observed primarily in the denture base followed by the cortical bone. PMID:22991634

Sadr, Katayoun; Alipour, Jahangir; Heidary, Fateme

2012-01-01

214

The effect of occlusal contact localization on the stress distribution in complete maxillary denture.  

PubMed

The fracture of acrylic resin dentures is an unresolved problem in removable prosthodontics despite many efforts to determine its cause. Unfavourable occlusion could be playing an important role in the fracture of the denture. The aim of this study was to investigate the effect of occlusal contact localization on the stress distribution in complete maxillary denture bases utilizing two-dimensional finite element analysis. The results of this study have shown that maximum compressive stresses in a complete maxillary denture under functional masticatory forces concentrates always on the artificial tooth/denture base junction irrespective to the occlusal contact localization. Tensile stresses were observed in areas toward the midline, although the midline itself usually had lower stresses. Shifting the occlusal contacts to a more buccal localization resulted in an increase of the calculated stresses. As a conclusion, it can be speculated that the buccal placement of the occlusal contacts may play a role in the fatigue fracture of the complete maxillary denture. PMID:16774509

Ate?, M; Cilingir, A; Sülün, T; Sünbülo?lu, E; Bozda?, E

2006-07-01

215

The use of computed tomography in the detection of radiolucent denture base material in the chest.  

PubMed

With the introduction of acrylic resin denture base materials to the dental profession, radiolucency was recognized as a significant deficiency at an early stage. Continuous research into the production of a radiopaque material has been directed at including radiopaque glasses, salts or metals powders in an otherwise radiolucent polymer. However, the majority of new dentures are still made in radiolucent material which is notoriously difficult to locate by conventional radiography and reports continue to appear relating to the inhalation or ingestion of dentures (or fragments of them), occasionally leading to the death of the patient. Advances in radiographic techniques and equipment have seen the development of computed tomography (CT). This has proved invaluable as a diagnostic aid for disease and therapy but little attention appears to have been given to the use of this sophisticated technique in the detection of foreign bodies, in particular those of dental origin. This study investigates the use of CT in the detection of radiolucent denture base material. The results suggest that CT has substantial advantages over conventional radiography in the detection of this material and should be considered as a valuable diagnostic aid in those patients thought to have inhaled dentures or fragments of dentures. PMID:3470468

Newton, J P; Abel, R W; Lloyd, C H; Yemm, R

1987-03-01

216

The impact of frenulum height on strains in maxillary denture bases  

PubMed Central

PURPOSE The midline fracture of maxillary complete dentures is a frequently encountered complication. The purpose of this study was to assess the effect of frenulum height on midline strains of maxillary complete dentures. MATERIALS AND METHODS A removable maxillary complete denture was fabricated and duplicated seven times. Four different labial frenulum heights were tested for stresses occurring on the palatal cameo surface. The strains were measured with strain gauges placed on 5 different locations and the stresses were calculated. To mimic occlusal forces bilaterally 100 N of load was applied from the premolar and molar region. RESULTS A statistically significant association between the height of the labial frenulum and the calculated stresses and strains was shown (P<.05) predominantly on the midline and especially on the incisive papilla. The results showed that stress on the anterior midline of the maxillary complete denture increases with a higher labial frenulum. CONCLUSION Within the limitations of this in vitro study, it can be concluded that the stress on the anterior midline of the maxillary complete denture increases with a higher labial frenulum. Surgical or mechanical precautions should be taken to prevent short-term failure of maxillary complete dentures due to stress concentration and low cycle fatigue tendency at the labial frenulum region. PMID:24353878

Bilhan, Hakan; Baysal, Gokhan; Sunbuloglu, Emin; Bozdag, Ergun

2013-01-01

217

A long term study on residual monomer release from denture materials.  

PubMed

The aim of this long term study was to investigate the release of residual monomer from different denture materials, throughout a 38 months time period after curing and storage in water Specimens made of four denture base resins (three heat polymerizing, one auto polymerizing) and one hard liner were subjected to residual monomer determination using gas liquid chromatography. The residual monomer estimation carried out on three occasions: one week, 12 months and 38 months after curing. The data obtained were analyzed using two-way Anova followed by Scheffe's test for post hoc multiple comparisons at alpha=0.05. Heat polymerized denture base acrylic resins showed less residual monomer than auto polymerized ones (p<0.001) and released no statistically significant amounts of monomer (p>0.05), during the 38 months storage time period. Auto polymerized denture materials, which had higher residual monomer content, released statistically significant amounts of monomer (p<0.001) during the first twelve months storage, but not during the last twenty six months period (p>0.05). Heat polymerized denture base acrylic resins released insignificant amounts of residual monomer during the storage period, whereas both the auto polymerized denture base resin and the hard liner released significant amounts of residual monomer during the initial storage time period but insignificant ones during the remainder of the storage period. PMID:18637384

Zissis, Alcibiades; Yannikakis, Stavros; Polyzois, Gregory; Harrison, Alan

2008-06-01

218

Tensile bond strength of four denture resins to porcelain teeth with different surface treatment  

PubMed Central

PURPOSE This study evaluated the bond strength between porcelain denture teeth (Bioblend 43D) and four different polymerized denture resins (Lucitone 199, Palapress, Acron MC, Triad) with and without a bonding agent and after four different types of surface treatment (polished, HF etched, sandblasted, air-abraded). MATERIALS AND METHODS Central incisor porcelain denture teeth were divided into 32 groups of 5 each. Tensile bond strength (MPa) was determined using a testing machine at crosshead speed of 0.5 mm/min. Mean and standard deviation are listed. Data were analyzed by two-way ANOVA. Means were compared by Tukey-Kramer intervals at 0.05 significance level. RESULTS All surface treatment increased bond strength compared to polished surface and the highest bond strength was found with Palapress resin with etched porcelain surface (8.1 MPa). Bonding agent improved the bond strength of all denture resins to porcelain teeth. Superior bonding was found with Palapress and air-abraded porcelain (39 MPa). CONCLUSION Resins with different curing methods affect the bond strength of porcelain teeth to denture bases. Superior bonding was found with auto-polymerized resin (Palapress). Application of ceramic primer and bonding agent to porcelain teeth with and without surface treatment will improve the bond strength of all denture resins to porcelain teeth. PMID:24353880

Powers, John

2013-01-01

219

Partial Eval Partial Eval  

E-print Network

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Sumii, Eijiro

220

Finite element analysis of stress distribution at the tooth-denture base interface of acrylic resin teeth debonding from the denture base.  

PubMed

Acrylic resin teeth present a problem when they detach unexpectedly from the denture base resin. Detachment is caused by stress concentrations at the tooth/denture base resin interface. In this study, the finite element method was used to examine the stress distribution at this interface when a single static force that resembled incisal bite force was applied. The results indicated that irrespective of the type of acrylic resin teeth used, maximum tensile stresses were found at the palatal aspect of the interface. It is suggested that boxing the tooth in the acrylic resin will help redistribute stress concentrations favorably. PMID:8778382

Darbar, U R; Huggett, R; Harrison, A; Williams, K

1995-12-01

221

Effect of various chemicals on the bond strength of acrylic tooth and denture base -An Invitro comparative study  

PubMed Central

Background: Debonding of acrylic teeth from the denture base is a common problem. Certain clinical conditions like ridge prominence leads to excess trimming of acrylic teeth and base, resulting in a weak interface. The denture base polymer debonds adhesively in the region of the highly cross –linked matrix of the teeth. To compare the effect of different chemical surface treatments on the bond between cross-linked acrylic teeth and different types of denture base material. Materials & Methods: A total of 180 wax specimens were fabricated and divided into 3 groups: Heat-cure, high impact heat-cure, flexible denture base material bonded to acrylic teeth. Each group was further subdivided into 6 subgroups with 10 specimens each according to the surface treatment ofthe ridge lap area: control, monomer, acetone 99%, chloroform 99%, acrylic adhesive cyanoacrylate, ethyl acetate 99%. After processing, specimens were tested for bond strength using a universal testing machine. The resulting bond strengths were recorded, statistically analyzed and compared. Results: Among all the 3types of denture base resins, highimpact heat-cure denture base resin gave highest bond strength. There was no bonding of teeth with flexible denture base material. Chemical surface treatment of acrylic teeth with ethyl acetate gave highest bond strength followed by control, chloroform, acetone and cyanoacrylate groups. Conclusion: Among all the 3types of denture base materials, high-impact heat-cure denture base resin gave highest bond strength with ethyl acetate surface treatment. Simple and quick tooth chemical surface treatment with ethylacetate could be an effective option in decreasing bonding failures and also avoid repeated denture repairs improving patient satisfaction. How to cite the article: Krishna VP, Premalatha A, Babu PJ, Raju DS, Kumar MP, Rao DB. Effect of various chemicals on the bond strength of acrylic tooth and denture base -An In-vitro comparative study. J Int Oral Health 2014;6(1):100-5. PMID:24653612

Krishna, V Pridhvi; Premalatha, Averneni; Babu, P Jithendra; Raju, D Srinivasa; Kumar, M Praveen; Rao, D Bheemalingeswara

2014-01-01

222

Effects of offset values for artificial teeth positions in CAD/CAM complete denture.  

PubMed

Recently, computer-aided design/computer-aided manufacturing (CAD/CAM) technology has been applied to the field of removable complete denture prosthodontics. We developed a system for fabricating complete dentures applying CAD/CAM technology. In this system, artificial teeth were bonded to the recesses of a milled denture base. However, the offset values needed for the recesses are not known. The purpose of the present study was to evaluate the accuracy of bonded artificial teeth positions in 0.00 (control), 0.10, 0.15, 0.20, and 0.25mm offset recess groups. Four types of artificial teeth, upper left central incisor (UL1), upper left canine (UL3), upper left first premolar (UL4), and upper left first molar (UL6), were used. Each type of artificial tooth was arranged at regular intervals on the denture base model with the CAD software. These data were defined as the master data. The artificial teeth parts were subtracted from the denture base model by Boolean logic operations in order to make recesses, and the recesses were then offset in five values. Based on these denture base data, prepolymerized resin blocks were milled (n=3). After bonding artificial teeth on the milled denture base model, a cone beam computed tomography (CBCT) scan was performed to obtain scanned data. Deviations between the master data and the scanned data were calculated. Based on the results, the optimal offset values were found to be 0.15-0.25mm for UL1, 0.15 and 0.25mm for UL3, 0.25mm for UL4, and 0.10-0.25mm for UL6. PMID:24981734

Yamamoto, Shinta; Kanazawa, Manabu; Iwaki, Maiko; Jokanovic, Ana; Minakuchi, Shunsuke

2014-09-01

223

Characterization and bacterial anti-adherent effect on modified PMMA denture acrylic resin containing platinum nanoparticles  

PubMed Central

PURPOSE This study characterized the synthesis of a modified PMMA (Polymethyl methacrylate) denture acrylic loading platinum nanoparticles (PtN) and assessed its bacterial inhibitory efficacy to produce novel antimicrobial denture base material. MATERIALS AND METHODS Polymerized PMMA denture acrylic disc (20 mm × 2 mm) specimens containing 0 (control), 10, 50, 100 and 200 mg/L of PtN were fabricated respectively. The obtained platinum-PMMA nanocomposite (PtNC) was characterized by TEM (transmission electron microscopy), SEM/EDX (scanning electron microscope/energy dispersive X-ray spectroscopy), thermogravimetric and atomic absorption spectrophotometer analysis. In antimicrobial assay, specimens were placed on the cell culture plate, and 100 µL of microbial suspensions of S. mutans (Streptococcus mutans) and S. sobrinus (Streptococcus sobrinus) were inoculated then incubated at 37? for 24 hours. The bacterial attachment was tested by FACS (fluorescence-activated cell sorting) analysis after staining with fluorescent probe. RESULTS PtN were successfully loaded and uniformly immobilized into PMMA denture acrylic with a proper thermal stability and similar surface morphology as compared to control. PtNC expressed significant bacterial anti-adherent effect rather than bactericidal effect above 50 mg/L PtN loaded when compared to pristine PMMA (P=.01) with no or extremely small amounts of Pt ion eluted. CONCLUSION This is the first report on the synthesis and its antibacterial activity of Pt-PMMA nanocomposite. PMMA denture acrylic loading PtN could be a possible intrinsic antimicrobial denture material with proper mechanical characteristics, meeting those specified for denture bases. For clinical application, future studies including biocompatibility, color stability and warranting the long-term effect were still required. PMID:25006385

2014-01-01

224

The prevalence of denture wearing and the impact on the oral health related quality of life among elderly in Kota Bharu, Kelantan  

Microsoft Academic Search

This study aims to determine the prevalence of denture wearing among elderly and to compare the oral health related quality of life (OHRQoL) between elderly with dentures and those without dentures. This cross sectional study involved 506 randomly selected edentulous elderly in the district of Badang, Kota Bharu, Kelantan. Consented participants were interviewed in the Kelantanese dialect at their homes

S. Zainab; N. M. Ismail; T. H. Norbanee; A. R. Ismail

2008-01-01

225

Preventing falls in older multifocal glasses wearers by providing single-lens distance glasses: the protocol for the VISIBLE randomised controlled trial  

Microsoft Academic Search

BACKGROUND: Recent research has shown that wearing multifocal glasses increases the risk of trips and falls in older people. The aim of this study is to determine whether the provision of single-lens distance glasses to older multifocal glasses wearers, with recommendations for wearing them for walking and outdoor activities, can prevent falls. We will also measure the effect of the

Mark J Haran; Stephen R Lord; Ian D Cameron; Rebecca Q Ivers; Judy M Simpson; Bonsan B Lee; Mamta Porwal; Connie Severino

2009-01-01

226

Plasmin and Epidermal Growth Factor in the Tear Fluid of Contact-Lens Wearers: Effect of Wearing Different Types of Contact Lenses and Association with Clinical Findings  

Microsoft Academic Search

The concentrations of plasmin and epidermal growth factor were determined in tear fluid (TF) samples from wearers of different types of contact lenses (CLs) during and after cessation of CL wear (CLW). TF samples of 50 healthy eyes served as controls. The plasmin concentrations in the control group (0.4 ± 0.1 ?g\\/ml; mean ± SEM) were significantly lower (p <

G.-B. van Setten; T. Tervo; R. Andersson; J. Perheentupa; A. Tarkkanen

1990-01-01

227

Investigation of bonding properties of denture bases to silicone-based soft denture liner immersed in isobutyl methacrylate and 2-hydroxyethyl methacrylate  

PubMed Central

PURPOSE The purpose of this study was to investigate the bonding properties of denture bases to silicone-based soft denture liners immersed in isobutyl methacrylate (iBMA) and 2-hydroxyethyl methacrylate (HEMA) for various lengths of time. MATERIALS AND METHODS Polymethyl methacrylate (PMMA) test specimens were fabricated (75 mm in length, 12 mm in diameter at the thickest section, and 7 mm at the thinnest section) and then randomly assigned to five groups (n=15); untreated (Group 1), resilient liner immersed in iBMA for 1 minute (Group 2), resilient liner immersed in iBMA for 3 minutes (Group 3), resilient liner immersed in HEMA for 1 minute (Group 4), and resilient liner immersed in HEMA for 3 minutes (Group 5). The resilient liner specimens were processed between 2 PMMA blocks. Bonding strength of the liners to PMMA was compared by tensile test with a universal testing machine at a crosshead speed of 5 mm/min. Data were evaluated by 1-way ANOVA and post hoc Tukey-Kramer multiple comparisons tests (?=0.05). RESULTS The highest mean value of force was observed in Group 3 specimens. The differences between groups were statistically significant (P<.05), except between Group 1 and Group 4 (P=.063). CONCLUSION Immersion of silicone-based soft denture liners in iBMA for 3 minutes doubled the tensile bond strength between the silicone soft liner and PMMA denture base materials compared to the control group. PMID:24843397

Tugut, Faik; Mutaf, Burcu; Guney, Umit

2014-01-01

228

The effect of impurities on the stress distribution at the tooth/denture base resin interface.  

PubMed

The most common cause of teeth detaching from the denture base is the presence of impurities along the tooth denture-base interface. However detachment after a period of wear of the denture probably occurs due to the presence of stress concentrations along the interface from which cracks may initiate. The presence of the impurity will inevitably lower the stress threshold for cracks to propagate thereby increasing the risk of tooth detachment. Although this is obvious, there is no evidence to show the effect of impurities on the stress distribution at this interface. This pilot study utilised the finite element method to examine stresses at the tooth-denture base interface in the presence of simulated impurities interspersed along different positions on the interface. Within the limitations of the two-dimensional model used, it was concluded that the presence of an impurity at the edge of the palatal aspect of the interface has a significant effect on the stress magnitude. However, the presence of impurities elsewhere along the interface had no significant effect on the stress magnitude. This would have important implications during the processing of dentures. PMID:9063108

Darbar, U R; Huggett, R; Harrison, A; Williams, K

1994-01-01

229

The impact of polymerization method on tensile bond strength between denture base and acrylic teeth.  

PubMed

Failure of the bond between acrylic teeth and the denture base resin interface is one of the major concern in prosthodontics. The new generation of denture bases that utilize alternate polymerization methods are being introduced in the market. The aim of the study is to evaluate the influence of polymerization methods on bonding quality between the denture base and artificial teeth. Sixty test specimens were prepared (20 in each group) and were polymerized using heat, microwave and visible light curing. The tensile strength was recorded for each of the samples, and the results were analyzed statistically. The light-activated Eclipse™ System showed the highest tensile strength, followed by heat curing. The microwave-cured samples exhibited the least bonding to the acrylic teeth. Within the limitations of this study, it can be concluded that the new generation of light-cured denture bases showed significantly better bonding to acrylic teeth and can be used as an alternative to the conventional heat-polymerized denture base. PMID:25307813

Hashem, Mohamed; Binmgren, Mohammed A; Alsaleem, Samah O; Vellappally, Sajith; Assery, Mansour K; Sukumaran, Anil

2014-01-01

230

Clinical success of implant-supported and tooth-implant-supported double crown-retained dentures.  

PubMed

The objective of this retrospective study was to compare biological and technical complications of implant-supported and tooth-implant-supported double crown-retained dentures (DCRDs) with those of tooth-supported DCRDs. Sixty-three DCRDs were monitored. One study group included 16 prostheses with a combination of implants and natural teeth as double crowns (ti group), whereas in the second study group, 19 dentures were retained exclusively on implants (ii group); a third study group with 28 exclusively tooth-supported dentures served as controls (tt group). Tooth loss, implant failure, and technical complications (loss of retention of primary crown, abutment screw loosening, loss of facing, fracture of resin denture teeth and fracture of saddle resin) were analysed. During the observation period of 24 months, no implants or teeth were lost in the ti group and three technical complications were recorded. In the ii group, two implants were lost, two cases of peri-implantitis occurred and four technical complications were observed. In the tt group, two cases of tooth loss and seven technical complications were observed. At the time of the last examination, all prostheses of the ti group and the ii group were functional. Patients of these two study groups reported high satisfaction with both function and aesthetics with no significant difference between the two groups. Treatment with DCRDs showed comparable results in the three study groups. The 2-year results indicate that double crowns can be recommended for implant and combined tooth-implant-retained dentures. PMID:21789591

Bernhart, Gunda; Koob, Andreas; Schmitter, Marc; Gabbert, Olaf; Stober, Thomas; Rammelsberg, Peter

2012-08-01

231

Elastic modulus and flexural strength comparisons of high-impact and traditional denture base acrylic resins  

PubMed Central

Background Fractures of acrylic resin dentures are a common occurrence in clinical dentistry. The denture may be fractured accidentally when dropped or while in service in the mouth due to flexural fatigue. Objectives The aim of this study was to compare the elastic modulus and the flexural strength between two heat-cured acrylic resins used in denture bases: a high-impact resin (Lucitone 199) and a traditional resin (Rodex). Materials and methods Rectangular strips of Lucitone 199 and Rodex (10 samples each) were fabricated and stored in artificial saliva at 37 °C for 2 weeks. The specimens were subjected to a three-point flexural test. The data were statistically analysed with Student’s t-test (p ? .05). Results The high-impact acrylic resin had a lower elastic modulus (p = .000) and higher flexural strength (p = .001) compared to the traditional acrylic resin. Conclusion Within the limitations of this study, it can be concluded that the high-impact acrylic resin is a suitable denture base material for patients with clinical fracture of the acrylic denture. PMID:24532960

Ajaj-ALKordy, Nour M.; Alsaadi, Mohannad H.

2013-01-01

232

Addition of a pontic to all-ceramic Turkom-Cera fixed partial denture restorations.  

PubMed

High-strength all-ceramic materials are commonly used in dentistry. When complications occur in an all-ceramic restoration, the restoration is usually replaced. This article describes the time-saving ability and cost-effectiveness of this novel technique for the addition of a pontic in two complicated clinical cases. Turkom-Cera(™) [Turkom-Ceramic (M) Sdn. Bhd.] with aluminum oxide (99.98%) is an all-ceramic system that offers the option of addition of a new pontic to the sintered framework. The new pontic was cut off from an alumina blank [Turkom-Ceramic (M) Sdn. Bhd.], moistened, and attached to the framework using alumina gel [Turkom-Ceramic (M) Sdn. Bhd.]. The framework was veneered with veneering porcelain (Vita VM 7; VITA Zahnfabrik). The two cases presented here involving the addition of a pontic to sintered framework were followed up for at least 1 year. No complication was detected or reported by the patients. Alumina- and zirconia-based ceramics are particularly suitable for for all-ceramic restorations in high-stress bearing areas. However, replacement of a failed all-ceramic restoration is not the most practical solution, considering both cost and tooth-related factors. This attractive feature of the Turkom-Cera allows the repair of a fractured ceramic coping or the addition of a new pontic to restorations. PMID:24883033

Uludag, Bulent; Tokar, Emre; Polat, Serdar

2013-04-01

233

The effect of aluminium on the metallography of a nickel base removable partial denture casting alloy.  

PubMed

Three special nickel-chromium alloys were prepared in which the aluminum levels were adjusted both above and below that of a commercial nickel base dental casting alloy. Tensile and metallographic evaluation of representative samples of the alloys were made and the changes in the properties of the alloys are reported. PMID:285671

Lewis, A J

1978-12-01

234

Mechanical evaluation and fem analysis of stress in fixed partial dentures zirconium-ceramic  

PubMed Central

SUMMARY Objective. Over the last several years, the Finite Element Analysis (FEM) has been widely recognized as a reference method in different fields of study, to simulate the distribution of mechanical stress, in order to evaluate the relative distribution of loads of different nature. The aim of this study is to investigate through the FEM analysis the stress distribution in fixed prostheses that have a core in Zirconia and a ceramic veneer supported by implants. Materials and methods. In this work we investigated the mechanical flexural strength of a ceramic material (Noritake®) and a of zirconium framework (Zircodent®) and the effects of the manufacturing processes of the material commonly performed during the production of fixed prostheses with CAD/CAM technology. Specifically three point bending mechanical tests were performed (three-point-bending) (1–3), using a machine from Test Equipment Instron 5566®, on two structures in zirconium framework-ceramic (structures supported by two implant abutments with pontic elements 1 and 2). A further in-depth analysis on the mechanical behavior in flexure of the specimens was conducted carrying out FEM studies in order to compare analog and digital data. Results. The analysis of the data obtained showed that the stresses are distributed in a different way according to the intrinsic elasticity of the structure. The analysis of FPD with four elements, the stresses are mainly concentrated on the surface of the load, while, in the FPD of three elements, much more rigid, the stresses are concentrated near the inner margins of the abutments. The concentration of many stresses in this point could be correlated to chipping (4) that is found in the outer edges of the structure, as a direct result of the ceramic brittleness which opposes the resilience of the structure subjected to bending. Conclusions. The analysis of the UY linear displacement confirms previous data, showing, in a numerical way, that the presence of the ceramic is related to the lowering of the structure. So, the reference values are those of the linear lowering obtained in the Mechanical Test and in our FEM analysis. zirconium framework with four elements 4,227 10?2mm.zirconium framework with ceramic structure with four elements 2,266 10?2 mm.That suggests that the presence of ceramics halves the flexion capabilities of the prosthetic materials. PMID:24772262

CARDELLI, P.L.; VERTUCCI, V.; BALESTRA, F.; MONTANI, M.; ARCURI, C.

2013-01-01

235

The effect of carbon on the metallography of a nickel base removable partial denture casting alloy.  

PubMed

This study has demonstrated the pattern of carbide development associated with progressive increases in carbon content in a series of six nickel chromium alloys. The carbon content is critical since it influences the production and distribution of carbides, which have been shown to alter the mechanical properties, of the nickel chromium alloys, that are dependent upon the development of gamma prime. Furthermore, it has been shown that the attainment of suitable strength is invariably associated with an unacceptable level of ductility. PMID:288385

Lewis, A J

1979-04-01

236

Addition of a pontic to all-ceramic Turkom-Cera fixed partial denture restorations  

PubMed Central

High-strength all-ceramic materials are commonly used in dentistry. When complications occur in an all-ceramic restoration, the restoration is usually replaced. This article describes the time-saving ability and cost-effectiveness of this novel technique for the addition of a pontic in two complicated clinical cases. Turkom-Cera™ [Turkom-Ceramic (M) Sdn. Bhd.] with aluminum oxide (99.98%) is an all-ceramic system that offers the option of addition of a new pontic to the sintered framework. The new pontic was cut off from an alumina blank [Turkom-Ceramic (M) Sdn. Bhd.], moistened, and attached to the framework using alumina gel [Turkom-Ceramic (M) Sdn. Bhd.]. The framework was veneered with veneering porcelain (Vita VM 7; VITA Zahnfabrik). The two cases presented here involving the addition of a pontic to sintered framework were followed up for at least 1 year. No complication was detected or reported by the patients. Alumina- and zirconia-based ceramics are particularly suitable for for all-ceramic restorations in high-stress bearing areas. However, replacement of a failed all-ceramic restoration is not the most practical solution, considering both cost and tooth-related factors. This attractive feature of the Turkom-Cera allows the repair of a fractured ceramic coping or the addition of a new pontic to restorations. PMID:24883033

Uludag, Bulent; Tokar, Emre; Polat, Serdar

2013-01-01

237

Bonded Orthodontic Retainer and Fixed Partial Denture Made with Fiber Reinforced Composite Resin  

PubMed Central

Retention is the phase of orthodontic treatment which maintains teeth in their orthodontically corrected positions, following the cessation of active orthodontic tooth movement. Development of resin-impregnated, fiber-reinforced composite materials has provided the potential to develop new approaches for stabilizing teeth and replacing teeth conservatively. This case report describes the rehabilitation of a patient with orthodontic and prosthetic problems. The long-term behavior of glass fibers splint must be evaluated in clinical studies. PMID:21494395

Kumbuloglu, Ovul; Saracoglu, Ahmet; Cura, Cenk; User, Atilla

2011-01-01

238

Resin-bonded fixed partial dentures. I. Proposed standardized criteria for evaluation.  

PubMed

Since etched cast resin-bonded prostheses were introduced in 1980, many articles have been written about them. Most state that the reported clinical success of these bonded restorations has been based primarily on the longevity of the bonding. For a comprehensive evaluation, however, it is important not only to examine the bonding but also to evaluate the periodontal response. The proposed standard method provides a consistent and comprehensive evaluation of resin-bonded prostheses that is applicable for researchers and clinicians alike. PMID:8897291

Wood, M; Thompson, V P; Romberg, E; Morrison, G V

1996-10-01

239

Unusual Case of Acanthamoeba polyphaga and Pseudomonas aeruginosa Keratitis in a Contact Lens Wearer from Gauteng, South Africa  

PubMed Central

Acanthamoeba species can cause a chronic, progressive ulcerative keratitis of the eye which is not responsive to the usual antimicrobial therapy and is frequently mistaken for stromal herpes keratitis. An unusual case of coinfection with Acanthamoeba polyphaga and Pseudomonas aeruginosa as causes of corneal keratitis in a contact lens wearer from Gauteng, South Africa, is reported. These two pathogens have previously been assumed to be selectively exclusive. Cysts of the isolated acanthameba tolerated an incubation temperature of 40°C, indicating a pathogenic species. This case highlights the importance of culture methods in the diagnosis of corneal infection and the choice of treatment regimen. The patient's history of careless contact lens-disinfecting habits emphasizes the need to adhere strictly to recommended methods of contact lens care. PMID:10655392

Dini, L. A.; Cockinos, C.; Frean, J. A.; Niszl, I. A.; Markus, M. B.

2000-01-01

240

Denture marking for forensic identification using memory card: an innovative technique.  

PubMed

Identification of individuals in crime or mass disaster is a daunting task for the forensic experts. The purpose of this study is to evaluate the feasibility of using a memory card for the forensic identification of dentures. The memory card was programmed with all the relevant information regarding the patient identification and the photograph of the patient. A recess was made in the maxillary denture's polished surface on the palatal aspect. The card was wrapped in cellophane, placed in the recess and then covered with pink auto polymerizing acrylic resin. On retrieval of the card from the denture, the entire data could be read as before without any distortion. The identification cards did not pose any problems in function and speech and were esthetically acceptable by the patients. PMID:24293920

Luthra, Reena; Arora, Saryu; Meshram, Suresh

2012-12-01

241

Effect of microwave disinfection on mechanical properties of denture base acrylic resin.  

PubMed

The microwave oven was used for sterilizing dentures contaminated with Candida albicans and other communicable diseases instead of disinfectant solutions. This study was carried out to evaluate the flexural properties, toughness, and impact strength of heat-cured acrylic resin sterilized by microwave oven either immersed in water or non-immersed for 5 and 15 min at full power. The results indicated that the microwave oven sterilization technique resulted in reduction of the load necessary to fracture the specimens, deformation at fracture, transverse strength, modulus of elasticity except disinfection at 5 min dry condition, toughness, and impact strength. This study concluded that the microwave oven is not acceptable for sterilization of dentures because of its weakening effects on the dentures that prone for fracture during clinical use. This method of sterilization increased the brittleness of acrylic resin specimens. PMID:20696412

Hamouda, Ibrahim M; Ahmed, Sabry A

2010-10-01

242

Physical Properties of Polyamide-12 versus PMMA Denture Base Material  

PubMed Central

Objectives. Polyamide-12 (PA) is a flexible material suited for denture bases and clasping. This study investigated its potential aging effects with a focus on surface roughness, color stability, and elasticity. Methods. PA specimens (Valplast) of 40 × 10 × 2?mm and equally measuring PMMA specimens (Palapress) as control were fabricated. Color changes after storage in air, water, coffee, and red wine (n = 10) were measured using the CIE L*a*b* color specification. Elasticity after thermocycling (1000, 3000, and 7000 cycles,??n = 15) was measured by three-point bending testing. Mean surface roughness (Ra) was determined after storage in the liquids mentioned above and thermocycling (n = 10). Results. Tukey's HSD test (P < 0.05) revealed statistically significant color changes of PA in red wine (?E = 4.27 after 12 days, ?E = 6.90 after 12 days) and coffee (?E = 3.93 after 36 days) but no color changes in PMMA. Elastic modulus of PA was 845?MPa and not affected by thermocycling (Tukey's HSD test,??P > 0.81). Dry specimens showed significantly decreased elasticity (P < 0.001). Mean surface roughness (PA 0.20??m, PMMA 0.28??m) did not change significantly after thermocycling or storage (Mann-Whitney U-test,??0.16 < P < 0.65). Significance. PA exhibited a higher susceptibility to discoloration than PMMA. Neither surface roughness nor elasticity of PA was altered by artificial aging. PMID:24734225

Wieckiewicz, Mieszko; Richter, Gert; Boening, Klaus W.

2014-01-01

243

A comparative study on complete and implant retained denture treatments - A biomechanics perspective.  

PubMed

Although implant-retained overdenture allows edentulous patients to take higher occlusal forces than the conventional complete dentures, the biomechanical influences have not been explored yet. Clinically, there is limited knowledge and means for predicting localized bone remodelling after denture treatment with and without implant support. By using finite element (FE) analysis, this article provides an in-silico approach to exploring the treatment effects on the oral mucosa and potential resorption of residual ridge under three different denture configurations in a patient-specific manner. Based on cone beam computerized tomography (CBCT) scans, a 3D heterogeneous FE model was created; and the supportive tissue, mucosa, was characterized as a hyperelastic material. A measured occlusal load (63N) was applied onto three virtual models, namely complete denture, two and four implant-retained overdentures. Clinically, the bone resorption was measured after one year in the two implant-retained overdenture treatment. Despite the improved stability and enhanced masticatory function, the implant-retained overdentures demonstrated higher hydrostatic stress in mucosa (43.6kPa and 39.9kPa for two and four implants) at the posterior ends of the mandible due to the cantilever effect, than the complete denture (33.4kPa). Hydrostatic pressure in the mucosa signifies a critical indicator and can be correlated with clinically measured bone resorption, pointing to severer mandibular ridge resorption posteriorly with implant-retained overdentures. This study provides a biomechanical basis for denture treatment planning to improve long-term outcomes with minimal residual ridge resorption. PMID:25560272

Chen, Junning; Ahmad, Rohana; Suenaga, Hanako; Li, Wei; Swain, Michael; Li, Qing

2015-02-01

244

Effect of denture cleansers on Candida albicans biofilm formation over resilient liners  

PubMed Central

PURPOSE The purpose of this study was to analyze the effect of denture cleansers on Candida albicans biofilm formation over resilient liners and to evaluate compatibility between resilient liners and denture cleansers. MATERIALS AND METHODS Acrylic resin (Lucitone 199®) and 3 resilient liners (COE-SOFT™, GC RELINE™ and SOFRELINER TOUGH TOUGH®) were incubated in denture cleansers (Polident® and Cleadent®) for 8 hours a day and in unstimulated saliva for 16 hours a day (n=25/gp) for 60 days. Two-way and three-way repeated measures ANOVA were performed to compare the surface roughness (Ra), pH and C. albicans binding level by radioisotope (?=0.05). The statistical significance of the relation between Ra and adhesion was evaluated by correlation analysis. RESULTS The degree of Ra was significantly decreased in the following order: COE-SOFT™, acrylic resin, GC RELINE™ and SOFRELINER TOUGH®. The immersion in denture cleansers significantly increased Ra of resilient liners, except for SOFRELINER TOUGH® in Cleadent®. No significant differences in pH curves were observed among groups immersed in distilled water and denture cleansers. The binding levels of C. albicans were significantly decreased in the following order: COE-SOFT™, GC RELINE™, SOFRELINER TOUGH®, and acrylic resin. The immersion in Cleadent® seemed to decrease C. albicans binding level on GC RELINE™ and SOFRELINER TOUGH®. CONCLUSION Based on the C. albicans binding levels results, it is not recommended to immerse COE-SOFT™ in denture cleansers, and GC RELINE™ and SOFRELINER TOUGH® should be immersed in Cleadent®. PMID:24843395

Huh, Jung-Bo; Lim, Younghun; Youn, Hye-In; Chang, Brian Myung; Lee, Jeong-Yol

2014-01-01

245

Hinged and sectional complete dentures for restricted mouth opening: A case report and review  

PubMed Central

Restricted mouth opening is a definite prosthodontic hindrance to carry out treatment successfully. Restricted mouth opening can be due to many reasons such as microstomia, oral submucous fibrosis, some genetic disorder, and as a result of some surgical treatment. In the past, various techniques for prosthetic rehabilitation of limited oral opening have been tried such as surgeries, use of dynamic opening devices, magnetic devices, and modification of denture design. Here we present; a simplified technique and simple design for fabrication of maxillary hinged and mandibular hinged and sectional complete denture for a patient with restricted mouth opening due to oral submucous fibrosis. PMID:23853457

Sharma, Aditi; Arora, Pallak; Wazir, Sartaj Singh

2013-01-01

246

The method of manufacture of nylon dental partially removable prosthesis using additive technologies  

NASA Astrophysics Data System (ADS)

The article is devoted to the topic of creating new methods of dental prosthesis. The aim of this work is to investigate the possibility of using additive technology to create nylon prosthesis. As a result of experimental studies, was made a sample of nylon partially removable prosthesis using 3D printing has allowed to simplify, accelerate and reduce the coat of manufacturing high-precision nylon dentures.

Kashapov, R. N.; Korobkina, A. I.; Platonov, E. V.; Saleeva, G. T.

2014-12-01

247

Stress analysis of a complete maxillary denture under various drop impact conditions: a 3D finite element study.  

PubMed

Complete maxillary dentures are one of the most economic and easy ways of treatment for edentulous patients and are still widely used. However, their survival rate is slightly above three years. It is presumed that the failure reasons are not only due to normal fatigue but also emerge from damage based on unavoidable improper usage. Failure types other than long-term fatigue, such as over-deforming, also influence the effective life span of dentures. A hypothesis is presumed, stating that the premature/unexpected failures may be initiated by impact on dentures, which can be related to dropping them on the ground or other effects such as biting crispy food. Thus, the behavior of a complete maxillary denture under impact loading due to drop on a rigid surface was investigated using the finite element method utilizing explicit time integration and a rate-sensitive elastoplastic material model of polymethylmethacrylate (PMMA). Local permanent deformations have been observed along with an emphasis on frenulum region of the denture, regardless of the point of impact. Contact stresses at the tooth-denture base were also investigated. The spread of energy within the structure via wave propagation is seen to play a critical role in this fact. Stress-wave propagation is also seen to be an important factor that decreases the denture's fatigue life. PMID:24945936

Sunbuloglu, Emin

2015-11-01

248

Evaluation of Cellular Toxicity of Three Denture Base Acrylic Resins  

PubMed Central

Objective This study aimed to evaluate the cellular toxicity of two newly-released acrylic resins (Futura Gen and GC Reline Hard) in comparison with the conventional heat-cure resin (Meliodent). Materials and Methods: Sample discs from each acrylic resin were placed in 24-well culture plates along with L929 mouse fibroblast cell line. A mixture of the RPMI 1640 medium, antibiotics and 10% FBS was added to the plates and the specimens were incubated in a CO2 incubator. The amount of light absorption by each plate was determined after 1 hour, 24 hours and 1 week by the MTT assay and ELISA. The cytotoxic effect of the resins was compared among groups using the two-way ANOVA and further paired comparison was performed using the post-hoc Tukey’s test. Results: After 1 hour, Futura Gen displayed a significantly lower level of light absorption in comparison with Meliodent (P=0.03). After 24 hours, GC Reline Hard rendered a significantly lower level of light absorption compared to Meliodent (P=0.02). After one-week of incubation, the mean absorption rates for GC Reline Hard, Meliodent and Futura Gen were relatively similar (P>0.05). The lowest and highest level of cytotoxicity among all resins were observed after one week and 1 hour of immersion in water, respectively. Conclusion: All the tested resins induced some degree of cytotoxicity. Cytotoxicity of Futura Gen, GC Reline Hard and Meliodent resins failed to show any significant reduction from 24 hours to one week. Thus, it is recommended to immerse the dentures in water for 24 hours prior to delivery to the patient. PMID:23323179

Ebrahimi Saravi, M.; Vojdani, M.; Bahrani, F.

2012-01-01

249

Influence of two functional complete-denture impression techniques on patient satisfaction: dentist-manipulated versus patient-manipulated.  

PubMed

This preliminary clinical study aimed to identify the impact of two border-molding techniques (dentist-manipulated and patient-manipulated) on patient satisfaction, the occlusal force at denture dislodgment, and number of pressure sores. Salivary flow rate and residual ridge resorption were analyzed as covariates. Thirty-six edentulous patients in need of a relining of their existing maxillary denture were included. After relining, no significant influence of the border-molding technique on any of the variables investigated could be identified. It can be concluded that the impact of the border-molding technique on patient satisfaction and denture function probably has been overestimated in the past. PMID:22146253

Wegner, Kerstin; Zenginel, Martha; Buchtaleck, Jochen; Rehmann, Peter; Wostmann, Bernd

2011-01-01

250

Studies on the effects of the spillway on the occlusal table of complete dentures upon the bearing of masticatory force.  

PubMed

We studied the effect of spillways in the posterior artificial teeth of complete dentures in reducing masticatory pressure on the basal mucosa by making completely edentulous patients masticate food. Using two kinds of experimental dentures, one with spillways on the occlusal table and the other without, five subjects wearing complete dentures were instructed to masticate four different types of test food. The results showed that the mastication time and the number of masticatory strokes were not much affected by the existence of spillways. However, the masticatory force of artificial teeth with spillways was slightly smaller than that of artificial teeth without spillways. PMID:9566124

Watanabe, K; Mizokami, T

1997-05-01

251

Incorporation of Radio Frequency Identification Tag in Dentures to Facilitate Recognition and Forensic Human Identification  

PubMed Central

Forensic identification using odontology is based on the comparison of ante-mortem and post mortem dental records. The insertion of a radio frequency identification (RFId) tag into dentures could be used as an aid to identify decomposed bodies, by storing personal identification data in a small transponder that can be radio-transmitted to a reader connected to a computer. A small passive, 12 x 2,1 mm, read-only RFId-tag was incorporated into the manufacture of three trial complete upper dentures and tested for a signal. The aim of this article is to demonstrate the feasibility of manufacturing such a dental prosthesis, the technical protocols for its implantation in the denture resin and its working principles. Future research and tests are required in order to verify human compatibility of the tagged denture and also to evaluate any potential deterioration in strength when subjected to high temperatures, or for damage resulting from everyday wear and tear. It should also be able to withstand the extreme conditions resulting from major accidents or mass disasters and procedures used to perform a forensic identification. PMID:20657641

Nuzzolese, E; Marcario, V; Di Vella, G

2010-01-01

252

A Denture with Hollow to Make Weight Shallow: A Case Report with a New Putty Method  

PubMed Central

To minimize the weight of the prosthesis various techniques that create a hollow prosthesis have been known. There are a lot of drawbacks of these techniques as they are complex, time consuming, and of high cost. Here is a technique that utilizes putty material for fabricating hollow denture prosthesis. PMID:25214742

Indrakumar, H S; Amarnath, G S; Shavi, Girish R; Hariprasad, A; Hilal, S Mohammed; Anand, M

2014-01-01

253

Factors affecting the bond strength of denture base and reline acrylic resins to base metal materials  

PubMed Central

Objective The shear bond strengths of two hard chairside reline resin materials and an auto-polymerizing denture base resin material to cast Ti and a Co-Cr alloy treated using four conditioning methods were investigated. Material and Methods Disk specimens (diameter 10 mm and thickness 2.5 mm) were cast from pure Ti and Co-Cr alloy. The specimens were wet-ground to a final surface finish of 600 grit, air-dried, and treated with the following bonding systems: 1) air-abraded with 50-70-µm grain alumina (CON); 2) 1) + conditioned with a primer, including an acidic phosphonoacetate monomer (MHPA); 3) 1) + conditioned with a primer including a diphosphate monomer (MDP); 4) treated with a tribochemical system. Three resin materials were applied to each metal specimen. Shear bond strengths were determined before and after 10,000 thermocycles. Results The strengths decreased after thermocycling for all combinations. Among the resin materials assessed, the denture base material showed significantly (p<0.05) greater shear bond strengths than the two reline materials, except for the CON condition. After 10,000 thermocycles, the bond strengths of two reline materials decreased to less than 10 MPa for both metals. The bond strengths of the denture base material with MDP were sufficient: 34.56 MPa for cast Ti and 38.30 for Co-Cr alloy. Conclusion Bonding of reline resin materials to metals assessed was clinically insufficient, regardless of metal type, surface treatment, and resin composition. For the relining of metal denture frameworks, a denture base material should be used. PMID:24037070

TANOUE, Naomi; MATSUDA, Yasuhiro; YANAGIDA, Hiroaki; MATSUMURA, Hideo; SAWASE, Takashi

2013-01-01

254

Flexural strength,water sorption and solubility of a methylmethacrylate-free denture base polymer reinforced with glass fibre reinforcement.  

PubMed

A methylmethacrylate-free denture base polymer (Eclipse) in comparison to a conventional denture base polymer (Palapress vario) was evaluated after water saturation and Stick glass fibre reinforcement. The data were analysed with ANOVA at a = 0.05. Water-storage caused a decrease in the flexural strength and stiffness of the materials (p > 0.05). Conventional denture base material with fibre reinforcement gave highest flexural strength (201.1 MPa) compared to fibre reinforced Eclipse (79.1 MPa) (p < 0.05). Water sorption after 76 days was 2.08% (Palapress vario) and 1.55% (Eclipse). Fibre-reinforcement of methylmethacrylate-free material was not as successful as conventional denture base and needs to be further optimized. PMID:24479210

Mutluay, M M; Tezvergil-Mutluay, A; Vallittu, P; Lassila, L

2013-12-01

255

Frequency of Traumatic Ulcerations and Post-insertion Adjustment Recall Visits in Complete Denture Patients in an Iranian Faculty of Dentistry  

PubMed Central

Background and aims The first few days following the insertion of complete dentures are critical for the patients since they are struggling to adapt to their new dentures. This study aimed to evaluate the most common locations of traumatic ulcerations, their frequency and also the duration and number of adjustment visits required to achieve patient comfort fol-lowing placement of complete dentures. Materials and methods Sixty patients were selected from edentulous patients referring to a removable prosthodontics department. Complete dentures were fabricated for the patients. After placement of dentures, all the patients were evaluated from the day after placement until patient comfort was achieved. Descriptive analysis was performed and chi-squared test was used to evaluate the associations between lesions, post-insertion visits and gender. Results A total of 85.8% of patients required denture adjustment because of mucosal injuries during their first visit fol-lowing denture placement. Maxillary and mandibular dentures did not require further adjustments after fourth and sixth visits, respectively. No significant differences were detected between males and females in the number of mucosal injuries in the anatomical areas evaluated in the maxilla and mandible using Fisher's exact test (P > 0.05). Furthermore, the number of mandibular dentures requiring adjustments was significantly higher than maxillary dentures in all the post-insertion ap-pointments (P < 0.001). Conclusion Since most mucosal injuries are located in the vestibule, adequate extension of denture flanges, especially during border molding, and use of pressure indicators that reveal over-extended borders, play an important role in decreas-ing mucosal injuries and improving patient comfort following complete denture placement. PMID:23019508

Sadr, Katayoun; Mahboob, Farhang; Rikhtegar, Elaheh

2011-01-01

256

Influence of Prosthetic Screw Material on Joint Stability in Passive and Non-Passive Implant-Supported Dentures  

PubMed Central

Objectives: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit. Methods: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures. Four groups (n=10) were tested, according to the vertical fit of the dentures [passive and non-passive] and prosthetic screw materials [titanium (Ti) or gold (Au) alloy]. The one-screw test was performed to quantify the vertical misfits using an optic microscope. The loosening torque for the prosthetic screws was measured 24 hours after the tightening torque (10 Ncm) using a digital torque meter. Data were analyzed by two-way ANOVA and Tukey’s test (?=0.05). Results: Overall, dentures with passive fit and Ti screws resulted in significantly higher loosening torque of the prosthetic screws (p<0.05). No significant interaction was found between fit level and screw material (p=0.199). The prosthetic screw material and fit of implant-supported dentures have an influence on screw joint stability. Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint. PMID:20148135

Spazzin, Aloísio Oro; Henriques, Guilherme Elias Pessanha; de Arruda Nóbilo, Mauro Antônio; Consani, Rafael Leonardo Xediek; Correr-Sobrinho, Lourenço; Mesquita, Marcelo Ferraz

2009-01-01

257

Effect of Simulated Microwave Disinfection on the Mechanical Properties of Three Different Types of Denture Base Resins  

PubMed Central

Statement of problem: Disinfection of prostheses with chemical solutions has deleterious effects on dentures. The appropriate power setting of microwave for disinfection, without affecting denture base properties, is a controversy. Purpose: To evaluate and compare the effect of simulated microwave disinfection at a recommended power setting on the mechanical properties of three denture base heat polymerized acrylic resins. Material and Methods: Ninety rectangular specimens of each acrylic resin of 65mm × 10mm × 3 mm dimensions were divided into three groups. Group A (Trevalon), Group B (Trevalon- HI), Group C (Ivocap). In each group, thirty specimens were divided into three subgroups with ten specimens in each and they were submitted to MicroVickers hardness, flexural strength, and impact strength tests. In each subgroup, five specimens were tested before the simulated microwave disinfection and they served as the control group. The remaining five were tested after simulated microwave disinfection and they were considered as the experimental group. Simulated microwave disinfection was done in a domestic microwave oven at 650 W for 5 minutes. Results: The data were analyzed using One-way ANOVA and t-test. The mechanical properties of the three denture base resins were not altered after simulated microwave disinfection, as compared to those of the controls. Conclusion: Microwave irradiation at 650 W for 5 min did not affect the mechanical properties of the three denture base resins. Domestic microwave oven, at the prescribed setting, can be used as an alternative method of disinfection for complete dentures without affecting their properties. PMID:24551725

Konchada, Jagadish; Karthigeyan, Suma; Ali, Syed Asharaf; R, Venkateshwaran; Amirisetty, Ramesh; Dani, Anurag

2013-01-01

258

Complete denture secondary impression technique to minimize distortion of ridge and border tissues.  

PubMed

A technique has been described with which a physiologic and anatomic registration of the attached and unattached tissue of the denture-bearing areas can be attained. Clear acrylic resin trays aid in eliminating excessive displacement at the secondary impression phase. Inadequacies of the mucostatic concept include: Failure to register the tissues, which are important for retention and stability Certain metal bases that are part of this procedure can be implemented by only a small number of technicians Increased cost There are two shortcomings of the tissue-loading technique for complete denture impressions. Resulting retention and stability lasts only for a short period of time. Unwanted ridge resorption and tissue changes occur. PMID:3903136

Klein, I E; Broner, A S

1985-11-01

259

Incorporation of antimicrobial macromolecules in acrylic denture base resins: a research composition and update.  

PubMed

Contemporary research in acrylic denture base materials focuses on the development of a novel poly(methyl methacrylate) (PMMA) resin with antimicrobial properties. Although PMMA resin has fulfilled all the requirements of an ideal denture base material, its susceptibility to microbial colonization in the oral environment is a formidable concern to clinicians. Many mechanisms including the absence of ionic charge in the methyl methacrylate resins, hydrophobic interactions, electrostatic interactions, and mechanical attachment have been found to contribute to the formation of biofilm. The present article outlines the basic categories of potential antimicrobial polymer (polymeric biocides) formulations (modified PMMA resins) and considers their applicability, biological status, and usage potential over the coming years. PMID:24138425

Sivakumar, Indumathi; Arunachalam, Kuthalingam Subbiah; Sajjan, Suresh; Ramaraju, Alluri Venkata; Rao, Bheemalingeshwara; Kamaraj, Bindu

2014-06-01

260

Magnet Retained Cheek Plumper in Complete Denture Esthetics: A Case Report  

PubMed Central

This clinical report describes a technique to improve support for sunken cheeks using magnet retained detachable acrylic cheek plumpers. The new generation of magnets with improved technology provides sufficient denture retention for clinical application. However, further follow-up may be necessary to ascertain the long-term usefulness of the magnet-retained prosthesis, because of corrosion and further loss of magnetism. PMID:24910682

Deogade, Suryakant Chhagan

2014-01-01

261

An In Vitro Analysis of Wear Resistance of Commercially Available Acrylic Denture Teeth  

Microsoft Academic Search

Posterior denture teeth wear faster than the anterior teeth, causing occlusal prematurities and loss of vertical dimension\\u000a of occlusion. The loss of vertical dimension of occlusion lays more stress on the anterior alveolar ridge, which in turn increases\\u000a the rate of residual ridge resorption and causes loss of alveolar ridge height in the anterior segment and compromises esthetics.\\u000a Hence it

Mallika S. Shetty; K. Kamalakanth Shenoy

2010-01-01

262

The effect of cleaning substances on the surface of denture base material  

PubMed Central

Bakcground The aim of this study was to evaluate the effect of substances used for hygienic cleaning of dentures on the surface of the denture base material. Material/Methods Meliodent Heat Cure (Heraeus-Kulzer, Germany) heat-polymerized acrylic resin was used to produce plates with all the characteristics of removable denture bases (subsequently, “plates”). Oral-B Complete toothbrushes of various brush head types were fixed to a device that imitated tooth brushing movements; table salt and baking soda (frequently used by patients to improve tooth brushing results), toothpaste (“Colgate Total”), and water were also applied. Changes in plate surfaces were monitored by measuring surface reflection alterations on spectrometry. Measurements were conducted before the cleaning and at 2 and 6 hours after cleaning. Results No statistically significant differences were found between the 3 test series. All 3 plates used in the study underwent statistically significant (p<0.05changed) – the reflection became poorer. The plates were most affected by the medium-bristle toothbrush with baking soda – the total reflection reduction was 4.82±0.1%; among toothbrushes with toothpaste, the hard-type toothbrush had the greatest reflection-reducing effect – 4.6±0.05%, while the toothbrush with table salt inflicted the least damage (3.5 ± 0.16%) due to the presence of rounded crystals between the bristles and the resin surface. Toothbrushes with water had a uniform negative effect on the plate surface – 3.89±0.07%. Conclusions All substances used by the patients caused surface abrasion of the denture base material, which reduced the reflection; a hard toothbrush with toothpaste had the greatest abrasive effect, while soft toothbrushes inflicted the least damage. PMID:24326781

Žilinskas, Juozas; Junevi?ius, Jonas; ?esaitis, K?stutis; Junevi?i?t?, Gabriel?

2013-01-01

263

Effect of surface treatments on the bond strength of different resin teeth to complete denture base material.  

PubMed

Although different commercial brands of artificial teeth are available in the market, debonding from the denture base is still an issue when rehabilitating edentulous patients with conventional or implant-supported complete dentures. The purpose of this study was to investigate the effect of surface treatments on the bond strength of four artificial teeth brands to a denture base material polymerized by microwave energy. Forty anterior artificial teeth of each brand (Biolux, Trilux, Biotone IPN, and Vipi Dent Plus) were bonded to denture base material (VipiWave). Before processing, groups often specimens of each brand received surface treatment: control, monomer application (MA), air abrasion (AA) or diatoric cavity (DC). After processing, a blinded examiner conducted the bond test by applying load to the specimens (0.5 mm/min, to 45 degrees). Data were analyzed by one-way ANOVA followed by Tukey's test (alpha = 0.05). Biolux teeth have stronger bonding to denture base than Trilux (p < 0.05) in control group; higher bond values than Biotone IPN (p < 0.05) in MA group; and higher bond strength than Vipi Dent Plus and Trilux (p < 0.01) in DC group; AA had no differential effect for any of the brands. With regard to the effect of the surface treatments on bond strength within groups of commercial brand, statistical analysis revealed no difference among them. According to results in general, Biolux teeth had the strongest bonding to the denture base material polymerized by microwave energy. Results may assist dentists in selecting denture teeth from the standpoint of shear bond strength. PMID:24294822

Meloto, Carolina B; Silva-Concílio, Laís R; Rodrigues-Garciai, Renata C M; Canales, Giancarlo T; Rizzatti-Barbosa, Célia M

2013-01-01

264

The role of surface treatments on the bond between acrylic denture base and teeth.  

PubMed

The aim of this study was to compare the bond strength between acrylic denture base and teeth subjected to 6 surface treatments. Ninety-six specimens were made with poly(methylmethacrylate) teeth bonded to a microwave-polymerized acrylic denture base material. The specimens were distributed into 6 groups (n=16) according to surface treatments: CT - no treatment (control); MN - methylmethacrylate monomer etching; AO - 50-microm-particle aluminum oxide air abrasion; BR - glaze removal with a round bur; ST - surface grinding with an aluminum oxide abrasive stone; group CV - cavity preparation (diatorics). The control and surface-treated groups were subjected to a compressive load at 45 masculine angle to the long axis of the teeth. Data were analyzed by one-way ANOVA, followed by Scheffé's test (p<0.05). Bond strength means and (SD) in kgf for groups were: CT: 18.19 (7.14), MN: 18.34 (5.28), AO: 23.82 (5.40), BR: 23.30 (4.79), ST: 25.39 (7.80) and CV: 17.48 (7.17). There was statistically significant difference (p=0.037997) only between ST and CV. In conclusion, ridge lap surface grinding with an aluminum oxide abrasive stone provided the highest bond strength, though it differed significantly only when compared to diatorics. The other surface treatments provided similar bond between the acrylic denture base and teeth. PMID:19738950

Bragaglia, Lauro Egídio; Prates, Luiz Henrique Maykot; Calvo, Maria Cristina Marino

2009-01-01

265

Photoelastic analysis to compare implant-retained and conventional obturator dentures  

NASA Astrophysics Data System (ADS)

The use of photoelastic analysis contributes to the rehabilitation of patients with oral-sinus-nasal sequelae, which in turn affect important functions such as chewing, swallowing, and speech. The prosthetic rehabilitation with implant-retained dentures is a suitable treatment option. The purpose of this study was to verify, by using a photoelastic analysis, the stress distribution in implant-retained palatal obturator dentures (relined or not) associated with different attachment systems (O-ring, bar-clip, and bar-clip associated with distally placed O-rings). Two photoelastic models were obtained from an experimental maxillary cast presenting an oral-nasal communication. One model had two 13-mm length implants placed on the left region. A total of eight colorless maxillary obturators were fabricated and subsequently four of them were relined with soft silicone soft, and three had attachment systems associated. The assembly (model/attachment system/prosthesis) was positioned in a circular polariscope and a 100-N load was applied at 10 mm/s. The results showed that the denture relining influenced the distribution and amount of stress on the models. The O-ring group displayed the lowest stress levels, followed by bar-clip system associated with distally placed O-rings and bar-clip groups.

Goiato, Marcelo Coelho; Prado Ribeiro, Paula do; Pellizzer, Eduardo Piza; Pesqueira, Aldiéris Alves; Haddad, Marcela Filiè; dos Santos, Daniela Micheline; Moreno, Amália

2012-06-01

266

[Influence of retainer design on fixation strength of resin-bonded glass fiber reinforced composite fixed cantilever dentures].  

PubMed

Fiber-reinforced composite (FRC) fixed partial dentures (FPD) have become an accepted part of the restorative dentist's armamentarium. The aim of this study was to evaluate in vitro the influence of retainer design on the strength of two-unit cantilever resin-bonded glass FRC-FPDs. Four retainer designs were tested: a dual wing, a dual wing + horizontal groove, a dual wing + occlusal rest and a step-box. Of each design on 7 human mandibular molars, FRC-FPDs of a premolar size were produced. The FRC framework was made of resin Revolution (Kerr) impregnated glass fibers (GlasSpan, GlasSpan) and veneered with hybrid resin composite (Charisma, Kulzer). Revolution (Kerr) was used as resin luting cement. FRC-FPDs were loaded to failure in a universal testing machine. T (Student's)-test was used to evaluate the data. The four designs were analyzed with finite element analysis (FEA) to reveal the stress distribution within the tooth/restoration complex. Significantly lower fracture strengths were observed with inlay-retained FPDs (step-box: 172±11 N) compared to wing-retained FPDs (p<0.05) (a dual wing + horizontal groove 222±9 N). The highest fracture strengths were observed with dual wing + occlusal rest FPDs: 250±10 N compared to inlay-retained FPDs (p<0.001) and wing-retained FPDs (p<0.001). FEA showed more favorable stress distributions within the tooth/restoration complex for dual wing retainers+ occlusal rest FPDs. There was stress concentration around connectors and retainers near connectors. A dual-wing retainer with occlusal rest is the optimal design for replacement of a single premolar by means of a two-unit cantilever FRC-FPDs. PMID:23715455

Petrikas, O A; Voroshilin, Iu G; Petrikas, I V

2013-01-01

267

The simulation and calculation of the fatigue of the lower complete denture in function by means of the finite element analysis.  

PubMed

This paper presents a finite element analysis, by which the stress distribution during function of a lower jaw acrylic-resin complete denture can be shown. The geometry of a prosthesis has been approximated by measuring, its elementary dimensions, as well as the dimensions of the characteristic cross-sections, on an already completed denture. Based upon these dimensions a mesh, (a three-dimensional network diagram) of finite elements was made. The results obtained are presented both graphically and numerically. The equivalent fatigue stresses, according to von Mises' energetic theory of firmness, expressed in MPa (or in N/mm2), are also shown. The results obtained enable us to gain an insight into lower complete denture fatigue, and could also be used when optimizing the shape of a denture. Furthermore, they could indicate possible causes of the fatigue fractures of a denture, particularly in the area between the left and the right canines. PMID:9722104

Panduri?, J; Husnjak, M; Guljas, K; Kraljevi?, K; Zivko-Babi?, J

1998-07-01

268

[New use of pulse-oximeter as a prophylactic Stimulator to the wearer and a lifesaving tools for prevention of hypoxic mishaps].  

PubMed

Pulse-oximeter has been widely used for the clinical assessment of physical status of a patient and as an alarming tool of hypoxia to medical personnel at the bedside or in the observation center. However, it has never been used for direct stimulation of the wearer. We considered innovation of pulse-oximeter as a prophylactic alarm-oximeter for the wearer. If SPO2 goes down to unfavorable level, the alarm-oximeter starts to send signal through a control box to a stimulator, such as an electrical nerve stimulator, a cold thermal tip, or mechanical device like a vibrator or compressor. The dermal stimulator is usually fixed to the right or left wrist with a Velcro band. The control box is affixed to the wristband by using Velcro. The alarm may be sent to an earphone or speaker with a verbal command like "take a deep breath". Alarm-oximeter will be combined to an oxygen inhaler or mechanical ventilatory assist device, or a drug administration system through electric line or wireless transmitter to start or change its function before the arrival of medical personnel. It will prevent hypoxic mishaps during medical intervention or sleep apnea syndrome. It will be also applicable to stop snoring. PMID:24724452

Morioka, Tohru; Terasaki, Hidenori

2014-03-01

269

Frequency of internal derangement of the temporomandibular joint in elderly individuals.  

PubMed

Elderly patients suffer from various systemic diseases and are likely to neglect their problems with functional disorders in the masticatory system, which are of crucial importance for successful prosthetic treatment. The purpose of the study was to establish the frequency of symptoms, clinical signs and tissue-specific diagnoses of internal derangement of the temporomandibular joint in elderly subjects and their relation with respect to gender and type of prosthetic replacement. The study was conducted on 96 subjects, 48 complete denture wearers and 48 removable partial denture wearers, whose average age was 75.8 years. The diagnostic procedure used in this study was manual functional analysis consisting of specific techniques of dynamic compressions and translations in diagnosing internal derangement of the temporomandibular joint. Chi-square test for independent samples was used for statistical analysis of the results. The symptoms of internal derangement of the temporomandibular joint were found in 9.3% of the subjects, and tissue-specific diagnoses were established in 52.1% of the subjects. The most common diagnoses were osteoarthrosis, total disk displacement with stable reposition and partial anterolateral disk displacement. No statistically significant differences in the frequency of symptoms, clinical signs and tissue-specific diagnoses were found between genders (P>.05) and complete and removable partial denture wearers (P>.05). The frequency of subjective symptoms of internal derangement in the temporomandibular joint of elderly subjects was low in relation to the frequency of intracapsular tissue-specific diagnoses. PMID:14594653

Dulci?, Niksa; Panduri?, J; Kraljevi?, S; Badel, T; Celi?, R

2003-10-22

270

Isolation of epithelial cells from acrylic removable dentures and gender identification by amplification of SRY gene using real time PCR  

PubMed Central

This study evaluates the usefulness of acrylic dentures as the source of DNA for forensic analysis. Thirty-eight samples (21 males and 17 females) were collected and stored for different time periods. The epithelial cells adhered to the dentures were retrieved and the genomic DNA was extracted. All the samples yielded sufficient amount of DNA for analysis irrespective of the storage time. Gender determination was done by amplification of the sex determining region on the Y chromosome (SRY) using real-time polymerase chain reaction with 100% accuracy, within minimal time. With this study, we conclude that saliva-stained acrylic dentures can act as a source of forensic DNA and co-amplification of SRY gene with other routine sex typing markers will give unambiguous gender identification. PMID:21189988

George, Renjith; Sriram, G; Saraswathi, TR; Sivapathasundharam, B

2010-01-01

271

A comparative study of retention of complete denture base with different types of posterior palatal seals – an in vivo study  

PubMed Central

Aim To evaluate retention of complete denture base with different types of posterior palatal seals. Material and methods Ten male patients between the age group of 50 years to 60 years were selected for the study. After the primary and secondary impressions were taken, five casts were made including a cast without posterior palatal seal, a cast with single bead posterior palatal seal, a cast with double bead posterior palatal seal, a cast with butterfly shaped posterior palatal seal, and a cast with posterior palatal seal with low fusing compound by functional method. Results It was observed that retention increased up to 108% in the posterior palatal seal with low fusing compound with functional method and the posterior palatal seal that was obtained by using functional method provided greater retention than a denture base without posterior palatal seal. Conclusion It was concluded that the incorporation of a posterior palatal seal is important for obtaining optimum retention of the maxillary complete denture. PMID:25473314

Chandu, GS; Hema, BS; Mahajan, Harsh; Azad, Antriksh; Sharma, Ipsita; Azad, Anurag

2014-01-01

272

In vitro evaluation of the bonding of auto-polymerizing soft denture liner to cobalt-chromium alloy.  

PubMed

This study evaluated the effects of surface pre-treatments on the bonding of auto-polymerizing silicone soft denture liner to a Co-Cr alloy denture base after cyclic thermal stressing. The bonding surfaces of Co-Cr alloy cylinders (8 mm diameter and 4 mm high) were polished with a 600-grit silicon carbide paper. The bonding surfaces received one of three pre-treatments, which included either the application of a metal primer, a metal primer after air abrasion, or a resin primer after adhesive resin coating. Tensile specimens were fabricated by polymerizing a 2-mm thickness of soft denture liner between a pair of pre-treated denture base cylinders. Failure loads were measured by tensile testing after subjecting the specimen to 0, 5, 10, 20, and 30 thousand thermal cycles. Seven specimens were fabricated for 15 groups, including three pre-treatments and five thermal cycle groups. Failure loads of resin-bonded specimens, which were formerly reported, were used as references. All data were statistically analysed by two-way anova and Bonferroni test at the 95% confidence level. Adhesive resin coating of the metal surface was effective in enhancing the failure loads up to 5000 thermal cycles. However, failure loads of all metal-bonded groups were significantly lower than those of resin-bonded groups at all thermal cycling intervals. The results of this in vitro study implied that polymerizing adhesive resin on the Co-Cr alloy might be a promising method, when the clinicians need to acquire improved bonding of an auto-polymerizing soft denture liner to Co-Cr alloy denture bases. PMID:15899025

Minami, H; Suzuki, S; Ohashi, H; Minesaki, Y; Tanaka, T

2005-06-01

273

Influence of high expansion dental stone used as investing medium on the changes in occlusal vertical dimension of complete dentures  

PubMed Central

Problem statement Despite advances in materials and techniques, complete dentures made of acrylic resin experience an increase in the occlusal vertical dimension (OVD) during processing. Many factors that affect the OVD of complete dentures are known. However, no study has examined the effect of using high-expansion dental stone (type V) as an investing material on the OVD. Purpose This study investigated the effects of using a high-expansion dental stone as an investing material on changes in the OVD of complete dentures. Material and methods Twenty sets of simulated upper and lower dentures were processed by the compression molding technique. Specimens were equally divided into 2 groups. In the dental stone type III (DST III) group, the lower, middle, and upper parts of a flask were filled with DST III. In the dental stone type V (DST V) group, the procedure was the same as in the DST III group, except that the middle layer was made of high-expansion DST V. Changes in the OVD were measured before and after denture processing. Collected data were analyzed with t-test statistics. Differences were considered statistically significant at the 95% confidence level. Results Both groups showed a small increase in the OVD as a result of processing, but the OVD increase was significantly less in the DST V group compared to the DST III group. Conclusion High-expansion DST V can be recommended as an investing material to reduce the increase in the OVD that may occur while processing complete dentures. PMID:24371379

Salloum, Alaa’a M.

2013-01-01

274

Longitudinal analysis of taurine induced effects on the tear proteome of contact lens wearers and dry eye patients using a RP-RP-Capillary-HPLC-MALDI TOF/TOF MS approach.  

PubMed

Tear proteomic studies revealed distinct similarities between contact lens wearers and dry eye patients. AMO Complete® multipurpose contact lens cleaning solutions containing taurine seem to have a beneficial effect regarding contact lens induced dry eye. To illuminate the effect of taurine on the tear proteome of contact lens wearers and sicca patients we developed a gel-based RP-RP capillary HPLC-MALDI TOF/TOF MS strategy. Two contact lens wearer groups, one using eye drops containing 0.05% taurine; the other for control physiological NaCl solution were monitored. Also, a third group of sicca patients using taurine solution was studied (N=4 individuals/group). Tear pools of each group at six time points over 5 weeks were analyzed. In summary 267 tear proteins were identified. We found a protein subset showing a linear taurine response with R(2) values ?0.5. Taurine effects were detected predominantly in the contact lens group demonstrated by distinct level decreases. Most protein candidates were related to inflammation. Since levels of these proteins differentiate from those of a healthy non-contact lens wearer reference they are supposed to be involved in contact lens induced dry eye and should be focused on in further studies. PMID:22480906

Funke, Sebastian; Azimi, Diana; Wolters, Dominik; Grus, Franz H; Pfeiffer, Norbert

2012-06-18

275

Effect of aging on tear strength and cytotoxicity of soft denture lining materials; in vitro  

PubMed Central

PURPOSE The aim of this in vitro study was to evaluate the effect of aging on the tear strength and cytotoxicity of four soft denture lining materials. MATERIALS AND METHODS Four commonly used soft denture lining materials, (Coe-Comfort™ GC America Inc., Alsip, IL, USA; Coe-Soft™ GC America Inc., Alsip, IL, USA; Visco-gel Dentsply Caulk Milford, DE, USA; and Sofreliner Tough M Tokuyama Dental Corporation Tokyo, Japan) were selected. Sixty trouser-leg designed specimens per lining material were fabricated using a stainless steel mold for tear strength testing. The specimens were divided into non-thermocycling and 1000-, and 3000- thermocycling groups. For the cytotoxicity test, twenty-four disk shaped specimens per material were fabricated using a stainless steel mold. The specimens were soaked in normal saline solution for 24 h, 48 h and 72 h. Cytotoxicity was measured by XTT assay in L929 mouse fibroblasts. Data were analyzed by two way analysis of variance and Dunnett's test (P<.05). RESULTS Before thermocycling, Sofreliner Tough M (10.36 ± 1.00 N) had the highest tear strength value while Coe-Comfort™ (0.46 ± 0.10 N) had the lowest. After 3000 cycles, Sofreliner Tough M (9.65 ± 1.66 N) presented the highest value and Coe-Comfort™ (0.42 ± 0.08 N) the lowest. Sofreliner Tough M, in all incubation periods was the least toxic with significant differences compared to all other materials (P<.05). Coe-Comfort™, Coe-Soft™, and Sofreliner Tough M did not show any significant differences within their material group for all incubation periods. CONCLUSION This in vitro study revealed that aging can affect both the tear strength and cytotoxicity of soft denture materials depending on the composition. PMID:24843396

Landayan, Jordi Izzard Andaya; Manaloto, Adrian Carlos Francisco; Shin, Sang-Wan

2014-01-01

276

[The causes of longitudinal fracture of the upper complete denture base].  

PubMed

Laying the strain gauge on the design areas of palatal base and frenum labiorum of complete dentures and simulating the different shapes of notch of frenums by the photoelastic mould. The test of the base condition under static and dynamic load by electrical measurement method was carried out. The longitudinal breaking line on the front part of the palatal base was first observed. The causes of breaking may be due to: the weak effect of notch of frenum labiorum; stress concentration on the front part of the base; material fatigue caused by the repeated alternate force and the strength of base material reduced by unsuitable processing. PMID:1306440

Li, G Z

1992-09-01

277

The effect of accelerated ageing on the mechanical properties of soft denture lining materials.  

PubMed

The purpose of this study was to determine the effect of simulated ageing on the physical properties of some soft denture liners. The hardness, tensile strength and percentage elongation values were determined before and after ageing treatment. At the end of the experimental ageing process softening was observed only in Simpa and Ufigel L materials. It was established that ageing had insignificant effect on the hardness of other materials. It can be presumed that there will not be significant time-related changes in the hardness of these materials. Molloplast B preserved its highest value after the ageing process, whilst that of Simpa decreased to become comparable with Ufigel P. PMID:10520150

Hekimo?lu, C; Anil, N

1999-09-01

278

Usage of low-intensity laser radiation for the treatment of the inflammatory processes of the oral cavity mucosa after applying removable plate dentures  

NASA Astrophysics Data System (ADS)

Effective methods of reveling overload zones of the oral mucosa under the bases of plane dentures, the effect of low intensity laser radiation ont he increase of its resistance are discussed. At present removable plate dentures of different modifications to a certain degree restore aesthetic proportions of the face, phonetics and malfunction of the teeth and jaws. Besides, removable bridge are known not to secure even distribution of mastication pressure along the whole dentures bed which results in the development of inflammatory and dystrophic processes, and, finally in the accelerated atrophy of the oral mucosa and bony tissue of the alveolar process of upper and alveolar parts of the mandible. Many papers are devoted to the anti-inflammatory effect of laser therapy. Improvement of metabolic processes and revascularization of the dentures bed mucosa, normalization of the oral microflora structure, anesthetizing effect is noted too. At the same time there are no papers about studying the therapeutic effect of low intensity laser radiation intraumatic dentures stomatitis, inflammation of the oral mucosa in the literature available for us. To increase the functional effectiveness of removable plate dentures, profilaxy of inflammation and dystrophic phenomena and to decrease adaptation period we have developed methods of early detection of overload zone of oral mucosa at the initial stages of acute inflammation with the help of macrohistochemical reaction. Visible with the naked eye for the timely and precise correction of the dentures.

Kalivradzhiyan, Edvard; Lesnykh, Nikolay; Kunin, Vadim; Mutafyan, Mikhail

1995-04-01

279

Efficacy of citric acid denture cleanser on the Candida albicans biofilm formed on poly(methyl methacrylate): effects on residual biofilm and recolonization process  

PubMed Central

Background It is well known that the use of denture cleansers can reduce Candida albicans biofilm accumulation; however, the efficacy of citric acid denture cleansers is uncertain. In addition, the long-term efficacy of this denture cleanser is not well established, and their effect on residual biofilms is unknown. This in vitro study evaluated the efficacy of citric acid denture cleanser treatment on C. albicans biofilm recolonization on poly(methyl methacrylate) (PMMA) surface. Methods C. albicans biofilms were developed for 72 h on PMMA resin specimens (n?=?168), which were randomly assigned to 1 of 3 cleansing treatments (CTs) overnight (8 h). CTs included purified water as a control (CTC) and two experimental groups that used either a 1:5 dilution of citric acid denture cleanser (CT5) or a 1:8 dilution of citric acid denture cleanser (CT8). Residual biofilms adhering to the specimens were collected and quantified at two time points: immediately after CTs (ICT) and after cleaning and residual biofilm recolonization (RT). Residual biofilms were analyzed by quantifying the viable cells (CFU/mL), and biofilm architecture was evaluated by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). Denture cleanser treatments and evaluation periods were considered study factors. Data were analyzed using two-way ANOVA and Tukey’s Honestly Significant Difference (HSD) test (??=?0.05). Results Immediately after treatments, citric acid denture cleansing solutions (CT5 and CT8) reduced the number of viable cells as compared with the control (p?denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this CT did not prevent biofilm recolonization. PMID:24957210

2014-01-01

280

Comparison of Graphoanalysis with House Method in Prediction of Complete Denture Patient's Mental Attitude: A Prospective Comparative Study.  

PubMed

To compare and evaluate House classification and graphoanalysis for the assessment of emotional status of complete denture patients. Fifty complete denture patients were included in the study. These patients were classified according to House classification as philosophical, exacting, indifferent and hysterical based on their behaviour during the course of the complete denture fabrication. Handwriting samples of these patients were obtained independently and the patient's emotional status was again classified by graphoanalysis. Statistical analyses like Chi-square, Spearman rank correlation, and Mann-Whitney U test were used to assess the expediency of both the methods in classifying complete denture patients. A significant correlation was found between results of graphoanalysis and those of clinical experience. Chances of observing highly difficult patients like hysterical were more from graphoanalysis than by clinical experience. Graphoanalysis is a useful tool for identification of difficult patients. Classification or categorization of patients by graphoanalysis and by clinical experience of patients differs significantly and graphoanalysis when coupled with clinical experience is more helpful in identification of difficult patients than merely by clinical experience alone. PMID:24431703

Murthy, J Varsha; Singh, Shyam; Shakila, R; Shastri, Mahadev

2013-03-01

281

Effect of thermal cycling on denture base and autopolymerizing reline resins  

PubMed Central

Objective: This study evaluated the fracture toughness (FT) of denture base and autopolymerizing reline resins, with and without thermocycling (T). Material and Methods: Specimens of each material (denture base acrylic resin - Lucitone 550 - L; autopolymerizing reline resins - Ufi Gel Hard-UH, Tokuyama Rebase II-TR, New Truliner- NT and Kooliner-K), were produced, notched and divided into two groups (n=10): CG (control group of autopolymerizing reline resins and L): FT tests were performed after polymerization; TG (thermocycled group): FT tests were performed after T (5ºC and 55ºC for 5,000 cycles). Results: Results (MPa.m(1/2)) were analyzed by two-way ANOVA and Tukey's test (p=0.05). L exhibited the highest FT mean values in both groups (CG - 2.33; TG - 2.17). For the CG groups, NT showed the highest FT (1.64) among the autopolymerizing reline resins, and K the lowest (1.04). After T, when the autopolymerizing reline resins were compared, a statistically significant difference in FT was found only between the NT (1.46) and TR (1.00). Conclusions: Thermocycling increased the FT of K and did not influence the FT of L, UH, TR and NT. PMID:23857648

SILVA, Cíntia de Souza; MACHADO, Ana Lucia; CHAVES, Carolina de Andrade Lima; PAVARINA, Ana Cláudia; VERGANI, Carlos Eduardo

2013-01-01

282

Biological effects of soft denture reline materials on L929 cells in vitro  

PubMed Central

Soft denture reline materials have been developed to help patients when their oral mucosa is damaged or affected due to ill-fitting dentures or post-implant surgery. Although reports have indicated that these materials leach monomers and other components that do affect their biocompatibility, there is little information on what cell molecules may be implicated in these material/tissue interactions. The biocompatibility of six soft liners (Ufi Gel P, Sofreliner S, Durabase Soft, Trusoft, Softone and Coe Comfort) was evaluated using a mouse fibroblast cell line, L929. Within 2 h of material disc preparation, each of the materials was exposed by direct contact to L929 cells for periods of 24 and 48 h. The effect of this interaction was assessed by alamarBlue assay (for cell survival). The expression of integrin ?5?1 and transforming growth factor ?1 was also assessed using plate assays such as enzyme-linked immunosorbent assay. Trusoft, Softone and Coe Comfort showed significantly reduced cell survival compared with the other soft lining materials at each incubation period. Furthermore, there were significant differences with these same materials in the expression of both integrin ?5?1 and transforming growth factor ?1. Soft liner materials may affect cell viability and cellular proteins that have important roles in wound healing and the preservation of cell viability and function in the presence of environmental challenges and stresses. PMID:25383166

Chaves, Carolina AL; Vergani, Carlos E; Thomas, Dominique; Young, Anne; Costa, Carlos AS; Machado, Ana L

2014-01-01

283

Dimensional Changes of Acrylic Resin Denture Bases: Conventional Versus Injection-Molding Technique  

PubMed Central

Objective: Acrylic resin denture bases undergo dimensional changes during polymerization. Injection molding techniques are reported to reduce these changes and thereby improve physical properties of denture bases. The aim of this study was to compare dimensional changes of specimens processed by conventional and injection-molding techniques. Materials and Methods: SR-Ivocap Triplex Hot resin was used for conventional pressure-packed and SR-Ivocap High Impact was used for injection-molding techniques. After processing, all the specimens were stored in distilled water at room temperature until measured. For dimensional accuracy evaluation, measurements were recorded at 24-hour, 48-hour and 12-day intervals using a digital caliper with an accuracy of 0.01 mm. Statistical analysis was carried out by SPSS (SPSS Inc., Chicago, IL, USA) using t-test and repeated-measures ANOVA. Statistical significance was defined at P<0.05. Results: After each water storage period, the acrylic specimens produced by injection exhibited less dimensional changes compared to those produced by the conventional technique. Curing shrinkage was compensated by water sorption with an increase in water storage time decreasing dimensional changes. Conclusion: Within the limitations of this study, dimensional changes of acrylic resin specimens were influenced by the molding technique used and SR-Ivocap injection procedure exhibited higher dimensional accuracy compared to conventional molding. PMID:25584050

Gharechahi, Jafar; Asadzadeh, Nafiseh; Shahabian, Foad; Gharechahi, Maryam

2014-01-01

284

Effect of Nanosilver on Thermal and Mechanical Properties of Acrylic Base Complete Dentures  

PubMed Central

Objective: Polymethyl methacrylate (PMMA), widely used as a prosthodontic base, has many disadvantages, including a high thermal expansion coefficient and low thermal conductivity, a low elasticity coefficient, low impact strength and low resistance to fatigue. This study aimed to make an in vitro comparison of the thermal conductivity, compressive strength, and tensile strength of the acrylic base of complete dentures with those of acrylic reinforced with nanosilver. Materials and Methods: For this study, 36 specimens were prepared. The specimens were divided into three groups of 12; which were further divided into two subgroups of control (unmodified PMMA) and test (PMMA mixed with 5 weight% nanosilver).The results were analysed by Independent t-test. Results: This study showed that the mean thermal conductivity and compressive strength of PMMA reinforced with nanosilver were significantly higher than the unmodified PMMA (P<0.05), while the tensile strength decreased significantly after the incorporation of nanosilver (P<0.05). Conclusion: Considering our results suggesting the favorable effect of silver nanoparticles on improving the thermal conductivity and compressive strength of PMMA, use of this material in the palatal area of maxillary acrylic resin dentures is recommended.

Hamedi-Rad, Fahimeh; Ghaffari, Tahereh; Rezaii, Farzad; Ramazani, Ali

2014-01-01

285

In vitro comparison of two different materials for the repair of urethan dimethacrylate denture bases  

PubMed Central

PURPOSE The purpose of this in vitro study was to investigate the flexural properties of a recently introduced urethane dimethacrylate denture base material (Eclipse) after being repaired with two different materials. MATERIALS AND METHODS Two repair groups and a control group consisting of 10 specimens each were generated. The ES group was repaired with auto-polymerizing polymer. The EE group was repaired with the Eclipse. The E group was left intact as a control group. A 3-point bending test device which was set to travel at a crosshead speed of 5 mm/min was used. Specimens were loaded until fracture occurred and the mean displacement, maximum load, flexural modulus and flexural strength values and standard deviations were calculated for each group and the data were statistically analyzed. The results were assessed at a significance level of P<.05. RESULTS The mean "displacement", "maximum load before fracture", "flexural strength" and "flexural modulus" rates of Group E were statistically significant higher than those of Groups ES and EE, but no significant difference (P>.05) was found between the mean values of Group ES and EE. There was a statistically significant positive relation (P<.01) between the displacement and maximum load of Group ES (99.5%), Group EE (94.3%) and Group E (84.4%). CONCLUSION The more economic and commonly used self-curing acrylic resin can be recommended as an alternative repair material for Eclipse denture bases. PMID:24353876

Cilingir, Altug; Bilhan, Hakan; Sulun, Tonguc; Bozdag, Ergun; Sunbuloglu, Emin

2013-01-01

286

Comparison of immediate complete denture, tooth and implant-supported overdenture on vertical dimension and muscle activity  

PubMed Central

PURPOSE To compare the changes in the occlusal vertical dimension, activity of masseter muscles and biting force after insertion of immediate denture constructed with conventional, tooth-supported and Implant-supported immediate mandibular complete denture. MATERIALS AND METHODS Patients were selected and treatment was carried out with all the three different concepts i.e, immediate denture constructed with conventional (Group A), tooth-supported (Group B) and Implant-supported (Group C) immediate mandibular complete dentures. Parameters of evaluation and comparison were occlusal vertical dimension measured by radiograph (at three different time intervals), Masseter muscle electromyographic (EMG) measurement by EMG analysis (at three different positions of jaws) and bite force measured by force transducer (at two different time intervals). The obtained data were statistically analyzed by using ANOVA-F test at 5% level of significance. If the F test was significant, Least Significant Difference test was performed to test further significant differences between variables. RESULTS Comparison between mean differences in occlusal vertical dimension for tested groups showed that it was only statistically significant at 1 year after immediate dentures insertion. Comparison between mean differences in wavelet packet coefficients of the electromyographic signals of masseter muscles for tested groups was not significant at rest position, but significant at initial contact position and maximum voluntary clench position. Comparison between mean differences in maximum biting force for tested groups was not statistically significant at 5% level of significance. CONCLUSION Immediate complete overdentures whether tooth or implant supported prosthesis is recommended than totally mucosal supported prosthesis. PMID:22737309

Shah, Farhan Khalid; Gebreel, Ashraf; Elshokouki, Ali hamed; Habib, Ahmed Ali

2012-01-01

287

The Effect of Different Chemical Surface Treatments of Denture Teeth on Shear Bond Strength: A Comparative Study  

PubMed Central

Background: The development of better cross linked acrylic resin teeth has solved the problems related to wearing and discoloration of acrylic teeth. The same cross linking at ridge lap region acts as a double edge sword as it weakens the bond between denture base and tooth. Aim of Study: The purpose of study was to evaluate the effect of surface treatment on the bond strength of resin teeth to denture base resin using monomethyl methacrylate monomer and dichloromethane with no surface treatment acting as control. Settings and Design:Denture base cylinder samples in wax (n=180) were made with maxillary central incisor attached at 450 (JIST 6506). These samples were randomly and equally divided into three groups of 60 each. These specimens were then flasked, dewaxed as per the standard protocol. Materials and Methods: Before acrylization, ridge lap area was treated as follows: Group A- no surface treatment act as control, Group B treated with monomethyl methacrylate monomer, Group C treated with dichloromethane. Digitally controlled acryliser was used for acrylization as per manufacturer’s instructions and shear bond strength was tested on Universal Testing Machine (Servo Hydraulic, 50kN High Strain, BISS Research). Statistical Analysis used: Result was statistically analyzed with One-way analysis of variance (ANOVA) and Post-hoc ANOVA Tukey’s HSD test at 5% level of significance. Results: The application of dichloromethane showed increased bond strength between cross linked acrylic resin teeth and heat cure denture base resin followed by monomethyl methacrylate monomer and control group. Conclusion: The application of dichloromethane on the ridge lap surface of the resin teeth before packing of the dough into the mold significantly increased the bond strength between cross linked acrylic resin teeth and heat cure denture base resin. PMID:25121057

Palekar, Umesh; Awinashe, Vaibav; Mishra, Sunil Kumar; Kawadkar, Abhishek; Rahangdale, Tripti

2014-01-01

288

Mathematical Methods for Assessing the Prognostic of Fixed Partial Dentures Resulting from Evaluating a Group of Dental Patients in Romania  

PubMed Central

Based on some mathematical and statistical approaches, our study leads to some conclusions concerning the procedures related to the orodental prosthetics. Occlusal equilibration in orodental prosthetics is a major issue because besides motivating patients for a regular daily oral hygiene, it could significantly increase the longevity of FPR. More dental hygiene information should be given after prosthetic treatment and patients should be motivated to attend recalls on a regular basis for professional teeth-cleaning. Interdental cleaning aids should be explained and the patients have to be motivated to use them at least once a day and the using technique should be individualized. Regarding the application of the deformable models theory, implemented in the context of an expert type software environment, it is known that the fact that modelling by advanced methods and techniques based on the deformable surfaces theory increases the efficiency of the dentofacial prosthetics procedures is a domain of great interest in the actual medical research. PMID:25013455

Mitrea, Alexandru I.; Badea, Iulia Clara; Chifor, Radu; Badea, Mindra Eugenia; Mitrea, Paulina; Popa, Sever; Crisan, Maria; Avram, Ramona

2014-01-01

289

Root canal therapy, fixed partial dentures and implant-supported crowns, have similar short term survival rates  

Microsoft Academic Search

Data sourcesSearches using the Medline, Cochrane and Embase databases and ‘citation mining’ (identifying references from included studies) were carried out. In addition, experts' recommendations for data sources were followed, and the table of contents of every issue of the most recent 2 years of a given list of dental journals were reviewed, the latter representing half of the total number

Ben Balevi

2008-01-01

290

[Partial algodystrophy].  

PubMed

Two patients are described with parcellar algodystrophy, a special form of algodystrophy. Bone biopsy in one patient revealed increased bone resorption and irregular new bone formation. Parcellar algodystrophy is characterized by the very localized pathological changes in the region of a joint. Only a small area of demineralization may be visible on X-ray. Skeletal scintigraphy shows hyperfixation of technetium-99m already in an early stage. Although the inflammatory signs are clinically impressive, the ESR may be normal. History may reveal previous involved joints. Parcellar algodystrophy normally runs a benign course. The difficulty of correct diagnosis is discussed. The changes are compared to those of partial algodystrophy and algodystrophy with no radiological abnormality throughout the course of the disease. PMID:2432654

Diethelm, U; Schlumpf, U; Musy, J P

1986-11-29

291

Technique of framework cemented on prepared abutments to obtain passive fit at fixed complete denture: a 2-year follow-up report.  

PubMed

The passive fit of implant-supported dentures is fundamental to the rehabilitation success due the absence of the periodontal ligament in osseointegrated implants. Many techniques to obtain passive fit have been reported in the literature, some inaccessible for the clinicians and dental laboratories. This case report presents a technique to fabricate fixed complete dentures aiming at obtain passive fit with reduced time and cost, but without demerit for the aesthetics, function and longevity. A 40-year-old woman was referred for treatment presenting some teeth in the maxilla and an edentulous mandible, reporting eating problems related to instability and little retention of the mandibular complete denture. Treatment based on the reverse planning was performed to guide the rehabilitation with a complete mandibular fixed complete denture and maxillary occlusal plane adjustment. The framework of the fixed complete denture was manufactured luting a cast metal bar above the prepared titanium cylinder abutments using resin cement. The aim of this technique was to obtain a fixed complete denture with passive fit presenting positive esthetic and functional outcomes after 2 years of follow-up. PMID:25590207

Spazzin, Aloísio Oro; Spazzin, Wagner Oro; Schuh, Christian; Bacchi, Ataís; Tosta, Vitória Bombig; Marcaccini, Andrea M

2014-12-01

292

A simplified numerical simulation method of bending properties for glass fiber cloth reinforced denture base resin.  

PubMed

The purpose of this study was to propose a new numerical modeling of the glass fiber cloth reinforced denture base resin (GFRP). The proposed model is constructed with an isotropic shell, beam and orthotropic shell elements representing the outmost resin, interlaminar resin and glass fiber cloth, respectively. The proposed model was applied to the failure progress analysis under three-point bending conditions, the validity of the numerical model was checked through comparisons with experimental results. The failure progress behaviors involving the local failures, such as interlaminar delamination and resin failure, could be simulated using the numerical model for analyzing the failure progress of GFRP. It is concluded that the model was effective for the failure progress analysis of GFRP. PMID:12238780

Tanimoto, Yasuhiro; Nishiwaki, Tsuyoshi; Nishiyama, Norihiro; Nemoto, Kimiya; Maekawa, Zen-ichiro

2002-06-01

293

Colour stability of acrylic resin denture teeth after immersion in different beverages.  

PubMed

The colour stability of acrylic resin denture teeth in beverages was investigated. A spectrophotometer measured the colour (CIE-L*a*b* system) of all specimens after storage in distilled water/for 24 h at 37 degrees C (T0). Specimens were then immersed in various beverages. After 15 days (T1) and 30 days (T2), for each material, the mean deltaE values were calculated and compared by two-way ANOVA and Tukey intervals (alpha = 0.05). In the deltaT0T1 period, specimens stored in red wine were significantly discoloured, compared to distilled water (P = 0.003). There was no difference between immersion solutions in deltaET0T2 (P = 0.772) and in deltaET1T2 (P = 0.058), and no difference between materials in all immersion periods. PMID:25134362

Arana-Correa, B E; Sepúlveda-Navarro, W F; Florez, F L E; Urban, V M; Jorge, J H; Campanha, N H

2014-06-01

294

Basic study on the application of novel functional monomers to a denture base resin.  

PubMed

To improve the mechanical properties and to reduce the water sorption amount of denture base resins, the polymerization characteristics of three novel fluoro-substituted monomers (MAF-TBN, MAF-MAE, MAF-TBN) and three styrene-type monomers (PTBS, PEES, PACS) were studied, as well as the copolymerization of these monomers with MMA. Subsequently, the mechanical properties and water sorption of the copolymers prepared from these monomers and MMA were evaluated. The polymerization reactivity of the monomers by BPO was lower than MMA, except for PACS. However, the copolymerization reactivity of the monomers with MMA was good, except for MAF-TBN. The copolymer of MAF-MAE and MMA in three fluoro-substituted monomers and PACS and MMA in three styrene-type monomers showed similar mechanical properties and extremely low water sorption compared with those of PMMA. PMID:18540403

Kurata, Shigeaki; Morishita, Kumiko; Shimoyama, Kazuo; Umemoto, Kozo

2008-03-01

295

Mechanical and thermal properties of polyamide versus reinforced PMMA denture base materials  

PubMed Central

PURPOSE This in vitro study intended to investigate the mechanical and thermal characteristics of Valplast, and of polymethyl methacrylate denture base resin in which different esthetic fibers (E-glass, nylon 6 or nylon 6.6) were added. MATERIALS AND METHODS Five groups were formed: control (PMMA), PMMA-E glass, PMMA-nylon 6, PMMA-nylon 6.6 and Valplast resin. For the transverse strength test the specimens were prepared in accordance with ANSI/ADA specification No.12, and for the impact test ASTM D-256 standard were used. With the intent to evaluate the properties of transverse strength, the three-point bending (n=7) test instrument (Lloyd NK5, Lloyd Instruments Ltd, Fareham Hampshire, UK) was used at 5 mm/min. A Dynatup 9250 HV (Instron, UK) device was employed for the impact strength (n=7). All of the resin samples were tested by using thermo-mechanical analysis (Shimadzu TMA 50, Shimadzu, Japan). The data were analyzed by Kruskal-Wallis and Tukey tests for pairwise comparisons of the groups at the 0.05 level of significance. RESULTS In all mechanical tests, the highest values were observed in Valplast group (transverse strength: 117.22 ± 37.80 MPa, maximum deflection: 27.55 ± 1.48 mm, impact strength: 0.76 ± 0.03 kN). Upon examining the thermo-mechanical analysis data, it was seen that the E value of the control sample was 8.08 MPa, higher than that of the all other samples. CONCLUSION Although Valplast denture material has good mechanical strength, its elastic modulus is not high enough to meet the standard of PMMA materials. PMID:23755341

Bolayir, Giray; Boztug, Ali

2013-01-01

296

Aesthetic analysis of an implant-supported denture at the cleft area.  

PubMed

Objective : To evaluate the aesthetics of an implant-supported denture at the cleft area, comparing the peri-implant tissues and prosthetic crown with the contralateral tooth. Settings : Hospital for Rehabilitation of Craniofacial Anomalies, Bauru, São Paolo, Brazil. Patients : A total of 39 individuals of both genders, with complete unilateral cleft lip and palate, who received secondary alveolar bone graft and were rehabilitated with single implant-supported dentures at the area of the missing maxillary lateral incisor after completion of orthodontic treatment. Interventions : The following parameters were analyzed in follow-up sessions: length and width of prosthetic crown and contralateral tooth, characteristics of implants, filling of interproximal space by the papilla, and smile height of the patients. Results : The implant-supported prosthetic crowns were longer than the contralateral tooth (p < .001). Among the 78 papillae analyzed, 29 (37.17%) received a score of 3; 32 (41.02%) papillae had a score of 2; and 17 (21.79%) received a score of 1. Concerning the smile height, among the 39 patients analyzed, 23 (56.41%) had a medium smile, 15 (38.46%) had a high smile, and two (5.12%) presented a low smile. Conclusion : The use of dental implants to rehabilitate the edentulous cleft area is an excellent option. However, adequate evaluation of the bone quantity and quality, positioning and shape of adjacent teeth, smile height, and patient expectations should be considered to achieve success and avoid aesthetic deformities such as elongated teeth and absence of gingival papillae. PMID:22616760

Filho, Jorge Francisco Fiamengui; de Almeida, Ana Lúcia Pompéia Fraga

2013-09-01

297

Analysis of the dependence of the stress state of cermet dentures on the sizes of the carcass span and bridges  

Microsoft Academic Search

A solution of the problem of rational design of cermet dental bridges is presented. An analysis of the stress-strain state\\u000a and a computer-aided solution of the boundary nonuniform elastic-plastic problem give the proportion of the bridge span size\\u000a to the height of the bridges of the metallic carcass at which the denture functions reliably up to the appearance of irreversible

E. N. Chumachenko; S. D. Arutynov; A. N. Gorbunova; V. A. Kozlov; I. V. Logashina

1998-01-01

298

Patterns of cell death induced by eluates from denture base acrylic resins in U-937 human monoblastoid cells.  

PubMed

The purpose of this study was to investigate in vitro the apoptosis- and necrosis-inducing potential of eluates from three heat-polymerized and four autopolymerized poly(methyl methacrylate)-based denture base resins. Our hypothesis was that the rate of cell death by apoptosis and/or necrosis induced by such denture base resins could be an important indicator of their cytotoxicity degree. U-937 human monoblastoid cells were exposed for 24 h and 48 h to eluates of 0.1 g/ml, 0.2 g/ml, 0.4 g/ml, and 0.8 g/ml extracted for 24 h and 48 h. The characteristics of apoptosis and necrosis were evaluated by flow cytometry and light and electron microscopy. Eluates from all resins enhanced cell death by apoptosis and necrosis in U-937 cells in a dose- and time-dependent fashion. Eluates from autopolymerized resins yielded higher percentages of apoptosis and necrosis than the heat-polymerized ones. The results support our hypothesis that eluates of poly(methyl methacrylate)-based denture base acrylic resins activate death-signaling pathways, and that the extent of this process reflects their biocompatibility degree. PMID:10706479

Cimpan, M R; Cressey, L I; Skaug, N; Halstensen, A; Lie, S A; Gjertsen, B T; Matre, R

2000-02-01

299

Live broadcast lectures on complete denture prosthodontics at Tokyo Medical and Dental University: comparison of two years.  

PubMed

A live broadcasting system was developed as part of dental education with Information and Communication Technology (ICT) at Tokyo Medical and Dental University. The purpose of this study was to utilize this system in complete denture prosthodontics, especially for the procedure of making a definitive impression with custom tray border molding in edentulous patients, and to evaluate its effectiveness. Live broadcast lectures on complete denture prosthodontics were given to fourth-year students in 2009 (fifty-nine students) and in 2010 (sixty-five students). To evaluate this lecture, a questionnaire was distributed to the students and faculty members after the lecture. Almost all the students and faculty members rated the lecture as good. Students commented that the lecture was "intelligible," "inspiring," "improved understanding," "good because they could ask questions in real time," "helped to know the actual time," "good for all the students to see the same case," and "close to real experience and induced a sense of tension." The results of this study suggested that a live broadcast lecture would help students experience the real clinical situation and aid in teaching complete denture prosthodontics. PMID:23486896

Iwaki, Maiko; Kanazawa, Manabu; Sunaga, Masayo; Kinoshita, Atsuhiro; Minakuchi, Shunsuke

2013-03-01

300

An optical coherence tomography investigation of materials defects in ceramic fixed partial dental prostheses  

NASA Astrophysics Data System (ADS)

Metal ceramic and integral ceramic fixed partial prostheses are mainly used in the frontal part of the dental arch because for esthetics reasons. The masticatory stress may induce fractures of the bridges. There are several factors that are associated with the stress state created in ceramic restorations, including: thickness of ceramic layers, mechanical properties of the materials, elastic modulus of the supporting substrate material, direction, magnitude and frequency of applied load, size and location of occlusal contact areas, residual stresses induced by processing or pores, restoration-cement interfacial defects and environmental defects. The fractures of these bridges lead to functional, esthetic and phonetic disturbances which finally render the prosthetic treatment inefficient. The purpose of this study is to evaluate the capability of optical coherence tomography (OCT) in detection and analysis of possible material defects in metal-ceramic and integral ceramic fixed partial dentures.

Sinescu, Cosmin; Negrutiu, Meda; Hughes, Michael; Bradu, Adrian; Todea, Carmen; Rominu, Mihai; Laissue, Philippe L.; Podoleanu, Adrian Gh.

2008-04-01

301

Cost-effectiveness of silicone and alginate impressions for complete dentures  

PubMed Central

Objective The aim of this study was to assess the cost effectiveness of silicone and alginate impressions for complete dentures. Methods Cost effectiveness analyses were undertaken alongside a UK single centre, double blind, controlled, crossover clinical trial. Taking the perspective of the healthcare sector, effectiveness is measured using the EuroQol (EQ-5D-3L) which provides a single index value for health status that may be combined with time to produce quality adjusted life years (QALYs); and Oral Health Impact Profile (OHIP-EDENT). Incremental cost effectiveness ratios are presented representing the additional cost per one unit gained. Results Mean cost was higher in the silicone impression group (£388.57 vs. £363.18). Negligible between-group differences were observed in QALY gains; the silicone group had greater mean OHIP-EDENT gains. The additional cost using silicone was £3.41 per change of one point in the OHIP-EDENT. Conclusions The silicone group was more costly, driven by the cost of materials. Changes in the EQ-5D and QALY gains over time and between arms were not statistically significant. Change in OHIP-EDENT score showed greater improvement in the silicone group and the difference between arms was statistically significant. Given negligible QALY gains and low level of resource use, results must be treated with caution. It is difficult to make robust claims about the comparative cost-effectiveness. Clinical significance Silicone impressions for complete dentures improve patients’ quality of life (OHIP-EDENT score). The extra cost of silicone impressions is £30 per patient. Dentists, patients and health care funders need to consider the clinical and financial value of silicone impressions. Different patients, different dentists, different health funders will have individual perceptions and judgements. ISRCTN01528038. NIHR-RfPB grant PB-PG-0408-16300.?? This article forms part of a project for which the author (TPH) won the Senior Clinical Unilever Hatton Award of the International Assocation for Dental Research, Capetown, South Africa, June 2014. PMID:24995472

Hulme, C.; Yu, G.; Browne, C.; O’Dwyer, J.; Craddock, H.; Brown, S.; Gray, J.; Pavitt, S.; Fernandez, C.; Godfrey, M.; Dukanovic, G.; Brunton, P.; Hyde, T.P.

2014-01-01

302

Silver colloidal nanoparticle stability: influence on Candida biofilms formed on denture acrylic.  

PubMed

Our aim in this study was to evaluate how the chemical stability of silver nanoparticles (SNs) influences their efficacy against Candida albicans and C. glabrata biofilms. Several parameters of SN stability were tested, namely, temperature (50ºC, 70ºC, and 100ºC), pH (5.0 and 9.0), and time of contact (5 h and 24 h) with biofilms. The control was defined as SNs without temperature treatment, pH 7, and 24 h of contact. These colloidal suspensions at 54 mg/L were used to treat mature Candida biofilms (48 h) formed on acrylic. Their efficacy was determined by total biomass and colony-forming unit quantification. Data were analyzed using analysis of variance and the Bonferroni post hoc test (? = 0.05). The temperature and pH variations of SNs did not affect their efficacy against the viable cells of Candida biofilms (P > 0.05). Moreover, the treatment periods were not decisive in terms of the susceptibility of Candida biofilms to SNs. These findings provide an important advantage of SNs that may be useful in the treatment of Candida-associated denture stomatitis. PMID:24951722

Monteiro, Douglas Roberto; Takamiya, Aline Satie; Feresin, Leonardo Perina; Gorup, Luiz Fernando; de Camargo, Emerson Rodrigues; Delbem, Alberto Carlos Botazzo; Henriques, Mariana; Barbosa, Debora Barros

2014-08-01

303

Oral health-related quality of life in patients with removable dentures.  

PubMed

The purpose of this study was to determine factors that affected oral health-related quality of life (Oral Health Related Quality of Life = OHRQoL) in patients with removable dentures (RD). Quality of life was evaluated by using the Geriatric Oral Health Assessment Index (GOHAI). We analysed data of 250 patients aged 63 ± 11.6 years. After excluding patients lacking relevant analysis data, 243 patients remained in the study, including 129 males and 114 females. Relevant parameters for good OHRQoL were: patient satisfaction with their RD (r = -0.317), higher age (r = 0.222), greater number of remaining teeth (r = 0.357), higher income (r = 0.175), higher frequency of dental visits (r = -0.212), tobacco abstinence (r = -0.181), and residence in a rural area (r = -0.420). Also, marital status had an impact on OHRQoL. Widowed and married patients showed the highest values and unmarried patients the lowest. Frequently mentioned problem areas considered within the survey were: the patient's fear of further tooth loss, concerns about functional aspects such as the decrease in chewing efficiency and dissatisfaction with the aesthetics of the dental prostheses. The results showed that the OHRQoL is apparently not only influenced by dental factors, but also by psychosocial and economic factors, the relevance of which would have to be shown in further studies. PMID:24420442

Pistorius, Jutta; Horn, Jan G; Pistorius, Alexander; Kraft, Joachim

2013-01-01

304

[Denture stomatitis: epidemiological study of 6,302 patients with removable dental prostheses].  

PubMed

This research was performed with the purpose of being acquainted with the frequency of onset of subprosthetic stomatitis in a large group of individuals and to determine some causal variables derivative of personal customs and habits of using prosthesis. The universe of study was represented by all the patients carrier of denture-plate for six months or more, who attended to 36 stomatologic clinics during a period of three uninterrupted weeks. A total of 6,302 individuals was examined and 2,952 of them were recorded as affected by subprosthetic stomatitis, for a rote of 46.84%; corresponding 50.47% to female sex and 39.96% to male sex. The most involved decade of life was that of 30 years, for 49.8%, and higher affection was observed in individuals using prosthesis with acrylic base, accounting for 48.45%. The largest amount of lesions, 63.04%, corresponded to clinical grade I. Of the individuals who estimated at the beginning of using fixed prosthesis, that such prosthesis were suitable and well fitted, 47.14% presented alterations. Of the individuals examined, 83.38% had the habit of sleeping with prosthesis, and 51.07% of them was affected by lesions. PMID:2639463

Díaz, E M; Baláez, A B; Vélez, J U; Lesa, J M

1989-01-01

305

Sorption, Solubility, Bond Strength and Hardness of Denture Soft Lining Incorporated with Silver Nanoparticles  

PubMed Central

The colonization of denture soft lining material by oral fungi can result in infections and stomatitis of oral tissues. In this study, 0 ppm to 200 ppm of silver nanoparticles was incorporated as an antimicrobial agent into composites to reduce the microbial colonization of lining materials. The effect of silver nanoparticle incorporation into a soft lining material on the sorption, solubility, hardness (on the Shore A scale) and tensile bond strength of the composites was investigated. The data were statistically analyzed using two-way ANOVA and Newman-Keuls post hoc tests or the chi-square Pearson test at the p < 0.05 level. An increase in the nanosilver concentration resulted in a decrease in hardness, an increase in sorption and solubility, a decrease in bond strength and a change in the failure type of the samples. The best combination of bond strength, sorption, solubility and hardness with antifungal efficacy was achieved for silver nanoparticle concentrations ranging from 20 ppm to 40 ppm. These composites did not show properties worse than those of the material without silver nanoparticles and exhibited enhanced in vitro antifungal efficiency. PMID:23271371

Chladek, Grzegorz; Kasperski, Jacek; Barszczewska-Rybarek, Izabela; ?mudzki, Jaros?aw

2013-01-01

306

Effect of Repeated Simulated Disinfections by Microwave Energy on the Complete Denture Base Adaptation  

PubMed Central

This study evaluated the effect of repeated microwave disinfections on the adaptation of the maxillar denture base using 2 different flask closure methods. Twenty stone cast-wax base sets were prepared for flasking by traditional cramp or RS system methods. Five bases for each method were submitted to 5 repeated simulated disinfections in a microwave oven with 650W for 3 minutes. Control bases were not disinfected. Three transverse cuts were made through each stone cast-resin base set, corresponding to canine, first molar, and posterior region. Measurements were made using an optical micrometer at 5 points for each cut to determine base adaptation: left and right marginal limits of the flanges, left and right ridge crests, and midline. Results for base adaptation performed by the flask closure methods were: traditional cramp (non-disinfected = 0.21 ± 0.05mm and disinfected = 0.22 ± 0.05mm), and RS system (non-disinfected = 0.16 ± 0.05 and disinfected = 0.17 ± 0.04mm). Collected data were submitted to ANOVA and Tukey test (?=.05). Repeated simulated disinfections by microwave energy did not cause deleterious effect on the base adaptation, when the traditional cramp and RS system flask closure methods were compared. PMID:19088884

Consani, Rafael L.X.; Iwasaki, Rose Y; Mesquita, Marcelo F; Mendes, Wilson B; Consani, Simonides

2008-01-01

307

Effect of repeated simulated disinfections by microwave energy on the complete denture base adaptation.  

PubMed

This study evaluated the effect of repeated microwave disinfections on the adaptation of the maxillar denture base using 2 different flask closure methods. Twenty stone cast-wax base sets were prepared for flasking by traditional cramp or RS system methods. Five bases for each method were submitted to 5 repeated simulated disinfections in a microwave oven with 650W for 3 minutes. Control bases were not disinfected. Three transverse cuts were made through each stone cast-resin base set, corresponding to canine, first molar, and posterior region. Measurements were made using an optical micrometer at 5 points for each cut to determine base adaptation: left and right marginal limits of the flanges, left and right ridge crests, and midline. Results for base adaptation performed by the flask closure methods were: traditional cramp (non-disinfected = 0.21 +/- 0.05mm and disinfected = 0.22 +/- 0.05mm), and RS system (non-disinfected = 0.16 +/- 0.05 and disinfected = 0.17 +/- 0.04mm). Collected data were submitted to ANOVA and Tukey test (alpha=.05). Repeated simulated disinfections by microwave energy did not cause deleterious effect on the base adaptation, when the traditional cramp and RS system flask closure methods were compared. PMID:19088884

Consani, Rafael L X; Iwasaki, Rose Y; Mesquita, Marcelo F; Mendes, Wilson B; Consani, Simonides

2008-01-01

308

Impact strength of denture base and reline acrylic resins: An in vitro study  

PubMed Central

This study evaluated the impact strength of a denture base resin (Lucitone 550—L) and four reline resins (Tokuyama Rebase II—T; Ufi Gel Hard—U; New Truliner—NT, and Kooliner—K), both intact and in a reline combination (L/L, L/T, L/U, L/NT, and L/K). For each group (n = 20), half of the specimens were thermocycled before testing. Charpy tests were performed, and the impact strengths were calculated. Data were analyzed by two-way analyses of variance and Tukey’s test (p = 0.05). For the intact groups, mean impact strength values for L (1.65 and 1.50) were significantly higher than those of the reline resins (0.38–1.17). For the relined groups, the highest mean impact strength values were produced by L/T (5.76 and 5.12), L/NT (6.20 and 6.03), and L/K (5.60 and 5.31) and the lowest by L/U (0.76 and 0.78). There were no significant differences between L and L/L. Thermocycling reduced the impact strength of T (from 0.73 to 0.38) and L/L (from 1.82 to 1.56). PMID:22977461

Bochio, Bruna C; Wady, Amanda F; Jorge, Janaina H; Canevarolo, Sebastião V; Vergani, Carlos E

2012-01-01

309

Effect of retorque on loosening torque of prosthetic screws under two levels of fit of implant-supported dentures.  

PubMed

This study evaluated the influence of retorque on loosening torque (Lt) of prosthetic screws in implant-supported dentures with different fit levels. Ten mandibular implant-supported dentures were fabricated and then 20 cast models were then prepared using prosthetic structures to create 2 fit levels: passive fit (Pf) and misfit (Mf). Two tightening techniques were also evaluated: initial torque only (T1); and initial torque and retorque after 10 min (T2). Gold or titanium screws were used, resulting in 4 groups to each one: Pf/T1, Pf/T2, Mf/T1, Mf/T2. The Lt was measured 24 h after the tightening torque using digital torque meter. Data were analyzed statistically by two-way ANOVA and Tukey's test (alpha=0.05), separately for each screw material. For titanium screws, no significant difference (p>0.05) was found between Pf/T1 and Pf/T2, or between Pf/T2 and Mf/T2. However, statistically significant difference (p<0.05) was found between Pf/T1 and Mf/T1, and between Mf/T1 and Mf/T2. Mf reduced the Lt using T1, while and T2 increased the Lt for Mf. Retorque and fit were shown to have no significant influence on the Lt of the gold screws. Retorque application made insignificant the misfit effect on the Lt of the titanium screws, suggesting that this procedure should be performed routinely during the screw tightening in multi-unit dentures. PMID:20464315

Spazzin, Aloísio Oro; Henrique, Guilherme Elias Pessanha; Nóbilo, Mauro Antônio de Arruda; Consani, Rafael Leonardo Xediek; Correr-Sobrinho, Lourenço; Mesquita, Marcelo Ferraz

2010-01-01

310

Effects of cleansing methods on 3-D surface roughness, gloss and color of a polyamide denture base material.  

PubMed

Abstract Objective. The purpose of this study was to determine the effects of two denture cleansing methods on 3-D surface roughness, gloss and color of denture base materials. Materials and methods. Thirty disks from nylon (Valplast) and 30 from heat-polymerized acrylic denture base material (Paladon 65) were made and 10 of each material were immersed in water (control), Val-Clean (peroxide cleanser) and Corega Extradent (peroxide cleanser) plus microwaving for a period simulating 30 days of daily cleansing. 3-D surface roughness, gloss and color parameters were measured before and after cleansing using an interferometric profilometer, a gloss meter and a colorimeter. The results were statistically analysed by regression, paired-t, Mann-Whitney and Kruskal-Wallis tests at ? = 0.05 level of significance. Results. The results showed significant differences at baseline in L* and b* parameters between materials (p < 0.01), with a significantly lower gloss (p < 0.05) and higher roughness (p < 0.05) for Valplast. After cleansing, ??* was significantly greater in Valplast than Paladon 65 (p < 0.05). Gloss of both materials decreased significantly within the Corega Extradent plus microwave solution (p < 0.05), while roughness increased significantly only for Paladon 65 (p < 0.05). Conclusions. Valplast was found to have a significantly lower gloss and a higher roughness than Paladon 65 before cleansing. After cleansing, ?E* increased more in Valplast than in Paladon 65, gloss of both materials decreased and roughness only of Paladon 65 increased within the Corega extradent plus microwaving method. PMID:25367196

Polychronakis, Nick C; Polyzois, Gregory L; Lagouvardos, Panagiotis E; Papadopoulos, Triantafillos D

2014-11-01

311

Effect of ridge lap surface treatment and thermocycling on microtensile bond strength of acrylic teeth to denture base resins.  

PubMed

This study evaluated the effect of denture base polymer type (heat- and microwave-polymerized), ridge lap surface treatment (with and without methyl methacrylate-MMA etching) and thermocycling on the microtensile bond strength (microTBS) of Biotone acrylic teeth. Flat-ground, ridge-lap surface of posterior artificial teeth were bonded to cylinders of each denture base resin, resulting in the following groups (n=6): G1a - Clássico/with MMA etching; G1b - Clássico/without MMA etching; G2a - OndaCryl/with MMA etching; G2b - OndaCryl/without MMA etching. Rectangular bar specimens with a cross-sectional area of 1 mm(2) were prepared. Half of the bars in each group were thermocycled (5,000 cycles between 4 degrees C and 60 degrees C). microTBS testing was performed in an universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically by three-way ANOVA (alpha=0.05). There was no statistically significant difference (p>0.05) for the factors (resin, surface treatment,and thermocycling) or their interactions. The mean microTBS values (MPa) and standard deviations were as follows: Thermocycling - G1a: 41.00 (14.00); G1b: 31.00 (17.00); G2a: 50.00 (27.00); G2b: 40.00 (18.00); No thermocycling - G1a: 37.00 (14.00); G1b: 43.00 (25.00); G2a: 43.00 (14.00); G2b: 40.00 (27.00). The microTBS of Biotone artificial teeth to the denture base acrylic resins was not influenced by the polymer type, surface treatment or thermocycling. PMID:19738945

Chaves, Carolina de Andrade Lima; Regis, Rômulo Rocha; Machado, Ana Lucia; Souza, Raphael Freitas de

2009-01-01

312

The effect of carbon fiber orientation on the fatigue resistance and bending properties of two denture resins.  

PubMed

The following conclusions were made concerning the effects of carbon fiber orientation on the flexural fatigue resistance and bending properties of two denture base acrylic resins. Hi-I resin, regardless of fiber presence or orientation, was more resistant to flexural fatigue than Lucitone resin. Carbon fibers placed perpendicular to the direction of applied stress produced the most favorable combination of increased resistance to bending and to flexural fatigue. Production of properly oriented fibers that are well centered within the resin is technically difficult and yields less predictable property improvements than result from randomly dispersed fibers. PMID:6583382

DeBoer, J; Vermilyea, S G; Brady, R E

1984-01-01

313

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

PubMed Central

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 has been registered at Deutsches Register Klinischer Studien (German register of clinical trials) under DRKS-ID: DRKS00003730 since 23 August 2012. (http://www.germanctr.de). PMID:24884848

2014-01-01

314

Numerical Simulation of Functional Evaluation for Implant-Supported Complete Maxillary Denture with an Efficient CT Image Segmentation and Mesh Creation Technique  

Microsoft Academic Search

Objective: This study aims to create twelve numerical models of implant-supported attachment-retained complete maxillary dentures by an efficient CT image segmentation and mesh creation technique, as well as evaluate mechanical characteristics of Model 1. Methods: Masks were first created after identifying regions of interest on CT scan images of maxillary prosthesis, then integrated with CAD models of implant, and finally

Lulu Gong; Xiaomei Li; Zuquan Ding

2010-01-01

315

[Effects of mold preheating temperatures and the time of melt casting on the structure of cast denture frameworks].  

PubMed

At casting temperatures of 1330 degrees to 1530 degrees C and preheating temperatures of 900 degrees to 1100 degrees C, 28 cast denture frameworks were manufactured using the cobalt chromium alloy Biosil f (Degussa). The inner defects were detected by X-ray defectoscopy and the grain numbers of clasp, connector and basis elements determined by metallography. The best results for compact castings were observed at a temperature range of 1410 degrees to 1480 degrees C. Casting previous to the melting of the last alloy cube results in a structure of clasps and connectors with 100-200 grains/mm2 and a high amount of defects; exceeding the liquidus temperature of 1380 degrees C produces grain numbers of 20-30/mm2, while a casting temperature of 1530 degrees C results in 3-5/mm2. Overheating of the melt, also in connection with low preheating temperatures, is probably a cause for the premature loss of clasp retention and fracture of many denture frameworks. PMID:2700705

Biffar, R; Balz, U

1989-11-01

316

A Multidisciplinary Approach to Full Mouth Rehabilitation and Solving the Dilemma of Wriggling Dentures- A Case Report  

PubMed Central

A successful management of full mouth rehabilitation demands a multi-disciplinary approach for its long lasting success. The present case report is intended to give an insight into the use of multiple treatment modalities to achieve a balanced, efficient and biomechanically successful prosthodontic treatment with acceptable aesthetics. Treatment of a maxillary and mandibular bilateral distal free end edentulous arch along with upper and lower anterior teeth requires plenty of contemporary and conventional prosthodontic treatment modalities. Management of distal extension situation provides complexity of biomechanical problems due to the three dimensional movements of the distal extension denture. A distal most implant can convert a distal extension RPD from a tooth and tissue supported prosthesis to a tooth and implant supported prosthesis which provides a definite stop thus enhancing the retention and stability of the prosthesis, eliminating the problems often associated with a tooth and tissue supported distal extension RPD. How to cite the article: Nidawani P, Galagali G, Reddy ES, Behera SS. A Multidisciplinary Approach to Full Mouth Rehabilitation and Solving the Dilemma of Wriggling Dentures- A Case Report. J Int Oral Health 2014;6(2):136-40. PMID:24876716

Nidawani, Prakash; Galagali, Girish; Reddy, E Srinivas; Behera, Sidhartha S P

2014-01-01

317

Partial tooth gear bearings  

NASA Technical Reports Server (NTRS)

A partial gear bearing including an upper half, comprising peak partial teeth, and a lower, or bottom, half, comprising valley partial teeth. The upper half also has an integrated roller section between each of the peak partial teeth with a radius equal to the gear pitch radius of the radially outwardly extending peak partial teeth. Conversely, the lower half has an integrated roller section between each of the valley half teeth with a radius also equal to the gear pitch radius of the peak partial teeth. The valley partial teeth extend radially inwardly from its roller section. The peak and valley partial teeth are exactly out of phase with each other, as are the roller sections of the upper and lower halves. Essentially, the end roller bearing of the typical gear bearing has been integrated into the normal gear tooth pattern.

Vranish, John M. (Inventor)

2010-01-01

318

[An attempt of introduction to prosthodontics of a non-contact device for measuring small configurations. Determining configurational changes during the individual steps of denture fabrication].  

PubMed

Denture fabrication involves a number of complex operations that have an effect on reproduction accuracy during each step of the process. Traditionally, metal patterns act as the standard for the mechanical properties of the main materials used in denture making. This means that doubts still remain in cases where the mucous membrane, with its complex configurations, is the object of investigation. The non-contact measuring instrument using laser light (known hereafter as "measuring instrument") enabled measuring small configurations. The measuring instrument enabled measurement of physical configurations that up to now were considered impossible to measure. The fabrication process up to creation of a denture base with the mucous membrane as the basic pattern was divided into four steps for measurement: mucous membrane, impression material, plaster and resin. The measuring device simultaneously carried out qualitative and quantitative analysis in three dimensions for all steps. Processing of test materials was unnecessary so that measurements could be accomplished in a very short time. Measurements revealed a variety of features, including those that are not affected by the physical properties of the materials for measurement. It was also possible to systematically investigate the various changes that take place during denture fabrication with the mucous membrane acting as the basic pattern. The following results were obtained: 1. The experiment confirmed possible application in dentistry of a non-contact device that uses laser light to measure extremely small configurations. 2. Results hint at the possibility of quantitative measurement of objects that cannot be directly measured with conventional methods. 3. During fabrication of dentures, it is very easy for changes in the total configuration to occur when taking impressions. Minute changes in the configuration occur on the surface when taking the plaster cast. During the final stage of the resin base, the tiny configurations became flat and resembled the configuration of the impression more than the original configuration of the mucous membrane. PMID:2134263

Morita, K

1990-06-01

319

Metallurgical evaluation of heat-treated nickel-chromium base denture alloy  

NASA Astrophysics Data System (ADS)

In this study, a combination of solution treatment at 1050°C for 60 min, quenching, and age hardening at 900°, 750° and 600°C for 6, 60, 600 min was carried out on as-east nickel-chromium-beryllium base denture alloy (Ticonium Premium 100 "Hard"). Changes in the microstructure following heat treatment have been investigated by light microscopy, while the composition of the microstructural constituents was determined by energy dispersive spectroscopy (EDS). The changes in the overall and dendritic Vickers hardness, which accompanied various heat treatments, were determined. X-ray diffraction, transmission electron microscopy and selected area diffraction were conducted to obtain direct crystallographic information about the phases present in the as-cast, solution-treated and aged conditions. It was shown that heat treatment has a profound effect on the microstructure of the as-cast Ticonium Premium 100 "Hard" alloy. In the as-cast condition, the alloy exhibited an inhomogeneous dendritic structure with oriented needle-like (Widmanstatten) precipitates and a discontinuous interdendritic eutectic structure. Solution treatment produced a homogenized structure as a result of dissolution of almost all the precipitates present in the as-cast condition. Aging of the solution-treated and quenched alloy, at 750°C and 600°C resulted in the precipitation of very fine precipitates in the dendritic matrix, whereas overaging was observed with aging at 900°C. There was a direct correlation between changes in the microstructure and the microhardness. The solution-treated alloy exhibited the lowest Vickers hardness value (200.5 +/- 6.5 kg/mm2), while the alloy aged at 750°C for 10 hours showed the highest value (359.1 +/- 8.1 kg/mm 2). Aging at 750° and 600°C showed a continuous increase in hardness with increasing the aging time. On the other hand the alloy aged at 900°C exhibited an increase followed by a decrease in hardness with increasing aging time. Changing the aging temperature for a given aging time caused a more pronounced effect on the microhardness than changing the aging time at a given temperature. There was no significant difference between the overall hardness and the dendritic hardness. Transmission electron microscopy and selected area diffraction in combination with x-ray diffraction studies revealed that this alloy consists of three phases in the as-cast and as-cast and aged conditions, the gamma (nickel rich) matrix phase, the NiBe eutectic phase and the gamma' (Ni3Al) precipitate phase. The strength and hardness properties of this alloy mainly depend on the precipitation of gamma' , which precipitates coherently with the gamma matrix phase.

Al Wakeel, Essam El Saeid

2000-10-01

320

Shear bond strength of resin teeth to heat-cured and light-cured denture base resin.  

PubMed

The failure of the bond between acrylic resin teeth and denture base material remains a considerable problem. Previous research has indicated that the introduction of a bonding agent to the tooth-resin interface significantly increased the tensile bond strength. To further investigate this finding, and to complement the earlier study, a shear strength assessment was carried out. Both a commercial and an experimental bonding agent were evaluated for tooth retention when applied to heat-cured and visible light-cured (VLC) resin. A significant increase in shear bond strength was obtained when bonding agents were applied. The experimental cement gave the greatest increase in strength, although the VLC resin failed to achieve the same degree of tooth attachment as the heat-cured resin. PMID:10792592

Cunningham, J L

2000-04-01

321

Standard of disocclusion in complete dentures supported by implants without free distal ends: analysis by the finite elements method  

PubMed Central

Objective The occlusal patterns are key requirements for the clinical success of oral rehabilitation supported by implants. This study compared the stresses generated by the disocclusion in the canine guide occlusion (CGO) and bilateral balanced occlusion (BBO) on the implants and metallic infrastructure of a complete Brånemark protocol-type denture modified with the inclusion of one posterior short implant on each side. Material and Methods A three-dimensional model simulated a mandible with seven titanium implants as pillars, five of them installed between the mental foramen and the two posterior implants, located at the midpoint of the occlusal surface of the first molar. A load of 15 N with an angle of 45º was applied to a tooth or distributed across three teeth to simulate the CGO or BBO, respectively. The commercial program ABAQUS® was used for the model development, before and after the processing of the data. The results were based on a linear static analysis and were used to compare the magnitude of the equivalent stress for each of the simulations. Results The results showed that the disocclusion in CGO generated higher stresses concentrated on the working side in the region of the short implant. In BBO, the stresses were less intense and more evenly distributed on the prosthesis. The maximum stress found in the simulation of the disocclusion in CGO was two times higher than that found in the simulation of the BBO. The point of maximum stress was located in the neck of the short implant on the working side. Conclusions Under the conditions of this study, it was concluded that the BBO pattern was more suitable than CGO for the lower complete denture supported by implants without free distal ends. PMID:22437680

GRECO, Gustavo Diniz; de LAS CASAS, Estevam Barbosa; CORNACCHIA, Tulimar P. Machado; de MAGALHÃES, Cláudia Silami; MOREIRA, Allyson Nogueira

2012-01-01

322

Partial Derivative Visualization Gallery  

NSDL National Science Digital Library

This resource is a small gallery of demos for illustrating partial derivatives geometrically. These animations can be used by instructors in a classroom setting or by students to aid in acquiring a visualization background for partial derivatives. Two file formats, gif and QuickTime files are used for the animations which can be downloaded.

Roberts, Lila F.

2004-11-11

323

Effect of surface preparation on the bond strength of heat-polymerized denture base resin to commercially pure titanium and cobalt-chromium alloy.  

PubMed

The aim of this study was to investigate the bond durability of heat-polymerized denture base resin to cast CP Ti and Co-Cr alloy. The alloy specimens were divided into five groups: 1) airborne-particle abraded with 50 µm alumina (SAND), 2) Rocatec tribochemical silica coating system (RO), 3) air-abraded followed by application of Epricord Opaque Primer (EP), 4) air-abraded followed by application of Super Bond C&B liquid (SB), 5) air-abraded followed by application of Alloy Primer (AL). Heat-polymerized denture resin was applied to the bonding area and polymerized according to the manufacturer's instructions. The halves of all specimens were thermocycled up to 10,000 cycles. Before thermocycling SB and AL showed significantly higher shear bond strengths than SAND, RO, EP for both metals. The shear bond strength of AL group after thermocycling was significantly higher than that of the other groups. PMID:21383520

Kawaguchi, Tomohiro; Shimizu, Hiroshi; Lassila, Lippo V J; Vallittu, Pekka K; Takahashi, Yutaka

2011-01-01

324

Strength of the bond between a silicone lining material and denture resin after Er:YAG laser treatments with different pulse durations and levels of energy  

Microsoft Academic Search

The purpose of this study was to investigate the tensile strength of the bond between a silicone lining material and heat-cured\\u000a polymethyl methacrylate (PMMA) denture base resin after Er:YAG laser treatment with different pulse durations and energy levels.\\u000a PMMA test specimens were fabricated and each received one of six surface treatments: no treatment (control), and five Er:YAG\\u000a laser treatments comprising

Faik Tugut; Hakan Akin; Burcu Mutaf; Gulsah Emine Akin; Ali Kemal Ozdemir

325

The Partial Derivative Machine  

NSDL National Science Digital Library

Research has shown that students struggle to understand the use of partial derivatives in thermodynamics. We have designed an apparatus, which we have called a Partial Derivative Machine, that serves as a mechanical analogue of a thermodynamic system. Using this device, students have a tangible way to wrestle with issues related to partial derivatives and thermodynamics, such as which variables are held fixed, how many variables are independent, and how energy can be added to a system. In this paper, we present a description of the apparatus, an introduction to the associated activities, and an overview of how this apparatus can be connected to thermodynamic systems.

Sherer, Grant; Kustusch, Mary B.; Manogue, Corinne A.; Roundy, David J.

2014-01-31

326

Partial Testing Design  

Cancer.gov

Statistical Software Partial Testing Design (Written by Stuart G. Baker) New Approach (with ROC curves): See Baker SG, Pinsky P. A proposed design and analysis for comparing digital and analog mammography: special ROC methods for cancer screening. JASA.

327

Partial Derivatives: Geometric Visualization  

NSDL National Science Digital Library

This write-pair-share activity presents Calculus III students with a worksheet containing several exercises that require them to find partial derivatives of functions of two variables. Afterwards, a series of Web-based animations are used to illustrate the surface of each function, the path of the indicated partial derivative for a specified value of the variable and the value of the derivative at each point along the path.

Rutledge, James

328

Laparoscopic Partial Nephrectomy  

Microsoft Academic Search

\\u000a Laparoscopic partial nephrectomy is an excellent management option for small, superficial renal masses. With experience, larger\\u000a and deeper tumors can be addressed as well. Intermediate-term follow-up (3- and 5-year) suggests cancer control similar to\\u000a that of open surgery. The benefit of laparoscopy over open surgery is a briefer and less intense convalescence. The disadvantage\\u000a of laparoscopic partial nephrectomy, at least

329

PARTIAL TORUS INSTABILITY  

SciTech Connect

Flux ropes are now generally accepted to be the magnetic configuration of coronal mass ejections (CMEs), which may be formed prior to or during solar eruptions. In this study, we model the flux rope as a current-carrying partial torus loop with its two footpoints anchored in the photosphere, and investigate its stability in the context of the torus instability (TI). Previous studies on TI have focused on the configuration of a circular torus and revealed the existence of a critical decay index of the overlying constraining magnetic field. Our study reveals that the critical index is a function of the fractional number of the partial torus, defined by the ratio between the arc length of the partial torus above the photosphere and the circumference of a circular torus of equal radius. We refer to this finding as the partial torus instability (PTI). It is found that a partial torus with a smaller fractional number has a smaller critical index, thus requiring a more gradually decreasing magnetic field to stabilize the flux rope. On the other hand, a partial torus with a larger fractional number has a larger critical index. In the limit of a circular torus when the fractional number approaches 1, the critical index goes to a maximum value. We demonstrate that the PTI helps us to understand the confinement, growth, and eventual eruption of a flux-rope CME.

Olmedo, Oscar; Zhang Jie, E-mail: oolmedo@gmu.ed [Department of Computational and Data Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)

2010-07-20

330

Finite element analysis to compare stress distribution of connector of lithia disilicate-reinforced glass–ceramic and zirconia-based fixed partial denture  

Microsoft Academic Search

This study used finite element method to analyze the stress distribution in connector of ceramic-based bilayer structures,\\u000a in simulation of dental crown-like structures with a functional but weak veneer layer bonded onto a strong core layer. The\\u000a purpose of this study was to evaluate the stress distribution at veneer\\/core interface of 2 different core materials [Yttria-stabilized\\u000a tetragonal zirconia polycrystals (Y-TZP)

Jie Lin; Akikazu Shinya; Harunori Gomi; Akiyoshi Shinya

331

Effect of Beverages on the Hardness and Tensile Bond Strength of Temporary Acrylic Soft Liners to Acrylic Resin Denture Base  

PubMed Central

Statement of Problem: Two potential problems commonly identified with a denture base incorporating a resilient liner are failure of the bond between acrylic resin and soft liner material, and loss of resiliency of the soft liner over time. Since patients may drink different beverages, it is important to evaluate their effects on physical properties of soft lining materials. Purpose: The objective of this in vitro study was to evaluate the effect of different beverages on the hardness of two temporary acrylic-based soft lining materials and their bond strength to the denture base resin. Materials and Method: For the hardness test; a total of 80 rectangular specimens (40mm×10mm×3mm) were fabricated from a heat-polymerized polymethylmethacrylate. Two commercially auto-polymerized acrylic resin-based resilient liners; Coe-Soft and Visco-gel were prepared according to the manufacturers’ instructions and applied on the specimens. For the tensile test, 160 cylindrical specimens (30mm×10mm) were prepared. The liners were added between specimens with a thickness of 3 mm. The specimens of both soft liners were divided into 4 groups (n=10) and immersed in distilled water as the control group, Coca-Cola, 8% and 50% ethanol. All groups were stored in separate containers at 37oC for 12 days. All beverages were changed daily. The hardness was determined using a Shore A durometer and tensile bond strength was determined in a ZwickRoell testing machine at a cross-head speed of 5mm/min. The results were analyzed using two-way ANOVA. Results: There was no significant interaction between the soft liners and the drinks for both hardness (p= 0.748) and bond strength (p= 0.902). There were statistically significant differences between all drinks for both hardness (p< 0.001) and bond strength (p< 0.05). Conclusion: Within the limitations of this study, it seems that drinking Coca-Cola and alcoholic beverages would not be potentially causing any problems for the temporary acrylic soft liners. PMID:24724142

Safari, A; Vojdani, M; Mogharrabi, S; Iraji Nasrabadi, N; Derafshi, R

2013-01-01

332

Methanol partial oxidation reformer  

DOEpatents

A partial oxidation reformer is described comprising a longitudinally extending chamber having a methanol, water and an air inlet and an outlet. An igniter mechanism is near the inlets for igniting a mixture of methanol and air, while a partial oxidation catalyst in the chamber is spaced from the inlets and converts methanol and oxygen to carbon dioxide and hydrogen. Controlling the oxygen to methanol mole ratio provides continuous slightly exothermic partial oxidation reactions of methanol and air producing hydrogen gas. The liquid is preferably injected in droplets having diameters less than 100 micrometers. The reformer is useful in a propulsion system for a vehicle which supplies a hydrogen-containing gas to the negative electrode of a fuel cell. 7 figs.

Ahmed, S.; Kumar, R.; Krumpelt, M.

1999-08-24

333

[Partial breast irradiation].  

PubMed

Owing to breast cancer screening, breast cancer is more and more diagnosed at early stage. For those breast cancer women, breast conserving treatment (breast conserving surgery followed by whole breast irradiation) is commonly used since many years. New radiation modalities have been recently developed in early breast cancers particularly accelerated partial breast irradiation (APBI). Among all techniques of radiotherapy, 3D-conformal APBI and intraoperative radiotherapy (IORT) are the main modalities of radiotherapy used. The present review states on indications, treatment modalities and updated results of local control and side effects of partial breast irradiation. PMID:24445657

Bourgier, Céline; Lemanski, Claire; Fenoglietto, Pascal; Riou, Olivier; Dubois, Jean Bernard; Azria, David

2014-01-01

334

Partial trisomy 3q  

Microsoft Academic Search

A new case of partial trisomy 3q is reported in a 5-year-old female with severe congenital malformations and psychomotor retardation. A review of the literature, with a total of 11 patients, allows us to conclude that the clinical picture reminiscent of the Cornelia de Lange syndrome is caused by the trisomic state.

E. Yunis; L. Quintero; A. Castefieda; E. Ramirez; M. Leibovici

1979-01-01

335

Partial Constraint Satisfaction  

Microsoft Academic Search

A constraint satisfaction problem involves finding values for variables subject to constraints on which combinations of values are allowed. In some cases it may be impossible or impractical to solve these problems completely. We may seek to partially solve the problem, in particular by satisfying a maximal number of constraints. Standard backtracking and local consistency techniques for solving constraint satisfaction

Eugene C. Freuder; Richard J. Wallace

1995-01-01

336

Implementing partial least squares  

Microsoft Academic Search

Partial least squares (PLS) regression has been proposed as an alternative regression technique to more traditional approaches such as principal components regression and ridge regression. A number of algorithms have appeared in the literature which have been shown to be equivalent. Someone wishing to implement PLS regression in a programming language or within a statistical package must choose which algorithm

M. C. Denham

1995-01-01

337

Familial partial 14 trisomy.  

PubMed Central

Four children in the same family have 47, +der (14), t(9;14) (p24;q21). Their mothers are sisters with 46,XX,t(9;14) (p24;q21). Clinical features of the children are similar to those of others reported to have partial 14 trisomy. Images PMID:469889

Miller, J Q; Willson, K; Wyandt, H; Jaramillo, M A; McConnell, T S

1979-01-01

338

SUPERCRITICAL WATER PARTIAL OXIDATION  

Microsoft Academic Search

In 2000, General Atomics was selected by DOE's Hydrogen Program to perform cooperatively- funded research on supercritical water partial oxidation (SWPO) of biomass, municipal solid waste (MSW), and high-sulfur coal to generate hydrogen. Phase I of this research is being performed in GA's privately-funded supercritical water (SCW) pilot plant at its San Diego, CA facilities. This pilot plant is a

N. W. Johanson; M. H. Spritzer; G. T. Hong; W. S. Rickman

339

Laparoscopic partial splenic resection.  

PubMed

Twenty domestic pigs with an average weight of 30 kg were subjected to laparoscopic partial splenic resection with the aim of determining the feasibility, reliability, and safety of this procedure. Unlike the human spleen, the pig spleen is perpendicular to the body's long axis, and it is long and slender. The parenchyma was severed through the middle third, where the organ is thickest. An 18-mm trocar with a 60-mm Endopath linear cutter was used for the resection. The tissue was removed with a 33-mm trocar. The operation was successfully concluded in all animals. No capsule tears occurred as a result of applying the stapler. Optimal hemostasis was achieved on the resected edges in all animals. Although these findings cannot be extended to human surgery without reservations, we suggest that diagnostic partial resection and minor cyst resections are ideal initial indications for this minimally invasive approach. PMID:7773460

Uranüs, S; Pfeifer, J; Schauer, C; Kronberger, L; Rabl, H; Ranftl, G; Hauser, H; Bahadori, K

1995-04-01

340

Partially-Filled Valley  

NASA Technical Reports Server (NTRS)

30 March 2006 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a valley which has become partially-filled with material. It is located west of Hellas Planitia. The valley, entering the scene from the east (right), turns toward the southwest (lower left) and splits to form a 'V'. Partially-filled depressions are common throughout the scene, including the circular feature near the top of the image. In each such case, the filling material is probably the remains of a material that once covered the entire scene.

Location near: 48.4oS, 318.1oW Image width: 3 km (1.9 mi) Illumination from: upper left Season: Southern Summer

2006-01-01

341

Influence of acrylamide monomer addition to the acrylic denture-base resins on mechanical and physical properties  

PubMed Central

The aim of the study was to evaluate the effect of adding acrylamide monomer (AAm) on the characterization, flexural strength, flexural modulus and thermal degradation temperature of poly(methyl methacrylate) (PMMA) denture-base resins. Specimens (n=10) were fabricated from a conventional heat-activated QC-20 (Qc-) and a microwave heat-activated Acron MC (Ac-) PMMA resins. Powder/liquid ratio followed the manufacturer's instructions for the control groups (Qc-c and Ac-c) and for the copolymer groups, the resins were prepared with 5% (?5), 10% (?10), 15% (?15) and 20% (?20) acrylamide contents, according to the molecular weight ratio, respectively. The flexural strength and flexural modulus were measured by a three-point bending test. The data obtained were statistically analyzed by Kruskal–Wallis test (?=0.05) to determine significant differences between the groups. The chemical structures of the resins were characterized by the nuclear magnetic resonance spectroscopy. Thermal stabilities were determined by thermogravimetric analysis (TGA) with a heating rate of 10 °C?min?1 from 35 °C to 600 °C. Control groups from both acrylic resins showed the lowest flexural strength values. Qc-15 showed significant increase in the flexural strength when compared to Qc-c (P<0.01). Ac-10 and Ac-15 showed significance when compared to Ac-c (P<0.01). Acrylamide incorporation increased the elastic modulus in Qc-10, Qc-15 and Qc-20 when compared to Qc-c (P<0.01). Also significant increase was observed in Ac-10, Ac-15 and Ac-20 copolymer groups when compared to Ac-c (P<0.01). According to the 1H-nuclear magnetic resonance (NMR) results, acrylamide copolymerization was confirmed in the experimental groups. TGA results showed that the thermal stability of PMMA is increased by the insertion of AAm. PMID:24030556

Aydogan Ayaz, Elif; Durkan, Rukiye

2013-01-01

342

Influence of various metal oxides on mechanical and physical properties of heat-cured polymethyl methacrylate denture base resins  

PubMed Central

PURPOSE To evaluate the effect of various metal oxides on impact strength (IS), fracture toughness (FT), water sorption (WSP) and solubility (WSL) of heat-cured acrylic resin. MATERIALS AND METHODS Fifty acrylic resin specimens were fabricated for each test and divided into five groups. Group 1 was the control group and Group 2, 3, 4 and 5 (test groups) included a mixture of 1% TiO2 and 1% ZrO2, 2% Al2O3, 2% TiO2, and 2% ZrO2 by volume, respectively. Rectangular unnotched specimens (50 mm × 6.0 mm × 4.0 mm) were fabricated and droptower impact testing machine was used to determine IS. For FT, compact test specimens were fabricated and tests were done with a universal testing machine with a cross-head speed of 5 mm/min. For WSP and WSL, discshaped specimens were fabricated and tests were performed in accordance to ISO 1567. ANOVA and Kruskal-Wallis tests were used for statistical analyses. RESULTS IS and FT values were significantly higher and WSP and WSL values were significantly lower in test groups than in control group (P<.05). Group 5 had significantly higher IS and FT values and significantly lower WSP values than other groups (P<.05) and provided 40% and 30% increase in IS and FT, respectively, compared to control group. Significantly lower WSL values were detected for Group 2 and 5 (P<.05). CONCLUSION Modification of heat-cured acrylic resin with metal oxides, especially with ZrO2, may be useful in preventing denture fractures and undesirable physical changes resulting from oral fluids clinically. PMID:24049564

Albayrak, Hamdi; Korkmaz, Turan; Turkyilmaz, Ilser

2013-01-01

343

A Prescription for Partial Synchrony  

E-print Network

Algorithms in message-passing distributed systems often require partial synchrony to tolerate crash failures. Informally, partial synchrony refers to systems where timing bounds on communication and computation may exist, but the knowledge...

Sastry, Srikanth

2012-07-16

344

Laparoscopic partial splenectomy  

Microsoft Academic Search

Background  The immunologic function of the spleen and its important role in immune defense has led to splenic-preserving surgery. This\\u000a study aimed to evaluate whether laparoscopic partial splenectomy is safe.\\u000a \\u000a \\u000a \\u000a Methods  Data on consecutive patients presenting with localized benign or malignant disease of the spleen were included in a prospective\\u000a database. The surgical technique consisted of six steps: patient positioning and trocar

S. Uranues; D. Grossman; L. Ludwig; R. Bergamaschi

2007-01-01

345

[Arthroscopic partial meniscectomy].  

PubMed

Partial closed meniscectomy under arthroscopic control is feasible in bucket handle tears and in some cases of L-shaped or longitudinal meniscal lesions. The operation is performed in general anesthesia but without hospitalization of the patient. Postoperative morbidity in 18 patients was surprisingly low, 16 patients being without disturbances two weeks after surgery. Mean duration of working inability was 6.5 days. For the experienced arthroscopist, low costs and decreased morbidity compared to arthrotomy recommend this procedure in selected cases of meniscal lesions. PMID:7440187

Glinz, W

1980-06-01

346

Partially segmented deformable mirror  

DOEpatents

A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp.

Bliss, Erlan S. (Danville, CA); Smith, James R. (Livermore, CA); Salmon, J. Thaddeus (Livermore, CA); Monjes, Julio A. (San Ramon, CA)

1991-01-01

347

Partially segmented deformable mirror  

DOEpatents

A partially segmented deformable mirror is formed with a mirror plate having a smooth and continuous front surface and a plurality of actuators to its back surface. The back surface is divided into triangular areas which are mutually separated by grooves. The grooves are deep enough to make the plate deformable and the actuators for displacing the mirror plate in the direction normal to its surface are inserted in the grooves at the vertices of the triangular areas. Each actuator includes a transducer supported by a receptacle with outer shells having outer surfaces. The vertices have inner walls which are approximately perpendicular to the mirror surface and make planar contacts with the outer surfaces of the outer shells. The adhesive which is used on these contact surfaces tends to contract when it dries but the outer shells can bend and serve to minimize the tendency of the mirror to warp. 5 figures.

Bliss, E.S.; Smith, J.R.; Salmon, J.T.; Monjes, J.A.

1991-05-21

348

Effect of leaching residual methyl methacrylate concentrations on in vitro cytotoxicity of heat polymerized denture base acrylic resin processed with different polymerization cycles  

PubMed Central

Objectives Residual methyl methacrylate (MMA) may leach from the acrylic resin denture bases and have adverse effects on the oral mucosa. This in vitro study evaluated and correlated the effect of the leaching residual MMA concentrations ([MMA]r) on in vitro cytotoxicity of L-929 fibroblasts. Material and Methods A total of 144 heat-polymerized acrylic resin specimens were fabricated using 4 different polymerization cycles: (1) at 74ºC for 9 h, (2) at 74ºC for 9 h and terminal boiling (at 100ºC) for 30 min, (3) at 74ºC for 9 h and terminal boiling for 3 h, (4) at 74ºC for 30 min and terminal boiling for 30 min. Specimens were eluted in a complete cell culture medium at 37ºC for 1, 2, 5 and 7 days. [MMA]r in eluates was measured using high-performance liquid chromatography. In vitro cytotoxicity of eluates on L-929 fibroblasts was evaluated by means of cell proliferation using a tetrazolium salt XTT (sodium 3´-[1-phenyl-aminocarbonyl)-3,4-tetrazolium]bis(4-methoxy-6-nitro)benzenesulphonic acid) assay. Differences in [MMA]r of eluates and cell proliferation values between polymerization cycles were statistically analyzed by Kruskal-Wallis, Friedman and Dunn's multiple comparison tests. The correlation between [MMA]r of eluates and cell proliferation was analyzed by Pearson's correlation test (p<0.05). Results [MMA]r was significantly (p?0.001) higher in eluates of specimens polymerized with cycle without terminal boiling after elution of 1 and 2 days. Cell proliferation values for all cycles were significantly (p<0.01) lower in eluates of 1 day than those of 2 days. The correlation between [MMA]r and cell proliferation values was negative after all elution periods, showing significance (p<0.05) for elution of 1 and 2 days. MMA continued to leach from acrylic resin throughout 7 days and leaching concentrations markedly reduced after elution of 1 and 2 days. Conclusion Due to reduction of leaching residual MMA concentrations, use of terminal boiling in the polymerization process for at least 30 min and water storage of the heat-polymerized denture bases for at least 1 to 2 days before denture delivery is clinically recommended for minimizing the residual MMA and possible cytotoxic effects. PMID:21956586

BURAL, Canan; AKTA?, Esin; DENIZ, Günnur; ÜNLÜÇERÇI, Ye?im; BAYRAKTAR, Gülsen

2011-01-01

349

Accelerated partial breast irradiation.  

PubMed

Local therapies to treat newly diagnosed breast cancer include a lumpectomy with radiation therapy or a mastectomy. The 20-year data from studies about the safety and efficacy of lumpectomy with full-breast radiation therapy support the safety of this regimen and its role to decrease the risk of ipsilateral recurrence and increase long-term survivorship of women with breast cancer. Accelerated partial breast irradiation (APBI) provides radiation therapy to the tumor bed but spares the remaining breast tissue. APBI accelerates the time required to complete the therapy regimen, with a range of one intraoperative session to five consecutive days compared to five to seven weeks. Several techniques exist to administer APBI, including the insertion of a balloon into the lumpectomy space. Of interest is the widespread use of APBI in community and academic settings that has preceded outcomes of large, randomized clinical trials. Because of selection bias in a number of small, single-institution, nonrandomized studies, published data are of limited value to ensure APBI as a standard of care. PMID:25253109

Bauer, Elfrida; Lester, Joanne L

2014-10-01

350

Partial disassembly of peroxisomes  

PubMed Central

Rat liver peroxisomes were subjected to a variety of procedures intended to partially disassemble or damage them; the effects were analyzed by recentrifugation into sucrose gradients, enzyme analyses, electron microscopy, and SDS PAGE. Freezing and thawing or mild sonication released some matrix proteins and produced apparently intact peroxisomal "ghosts" with crystalloid cores and some fuzzy fibrillar content. Vigorous sonication broke open the peroxisomes but the membranes remained associated with cores and fibrillar and amorphous matrix material. The density of both ghosts and more severely damaged peroxisomes was approximately 1.23. Pyrophosphate (pH 9) treatment solubilized the fibrillar content, yielding ghosts that were empty except for cores. Some matrix proteins such as catalase and thiolase readily leak from peroxisomes. Other proteins were identified that remain in mechanically damaged peroxisomes but are neither core nor membrane proteins because they can be released by pyrophosphate treatment. These constitute a class of poorly soluble matrix proteins that appear to correspond to the fibrillar material observed morphologically. All of the peroxisomal beta-oxidation enzymes are located in the matrix, but they vary greatly in how easily they leak out. Palmitoyl coenzyme A synthetase is in the membrane, based on its co-distribution with the 22-kilodalton integral membrane polypeptide. PMID:2989301

1985-01-01

351

Low partial discharge vacuum feedthrough  

NASA Technical Reports Server (NTRS)

Relatively discharge free vacuum feedthrough uses silver-plated copper conductor jacketed by carbon filled silicon semiconductor to reduce concentrated electric fields and minimize occurrence of partial discharge.

Benham, J. W.; Peck, S. R.

1979-01-01

352

Trigonometric Integrals via Partial Fractions  

ERIC Educational Resources Information Center

Parametric differentiation is used to derive the partial fractions decompositions of certain rational functions. Those decompositions enable us to integrate some new combinations of trigonometric functions.

Chen, H.; Fulford, M.

2005-01-01

353

A comparative evaluation of the dimensional accuracy of heat polymerised PMMA denture base cured by different curing cycles and clamped by R S technique and conventional method – An In-vitro study  

PubMed Central

Background: The aim of this study is to evaluate the dimensional accuracy of heat polymerized PMMA denture base clamped by the conventional method and by R.S technique and cured by a different curing cycle. Materials & Methods: In this study, a total of 40 standardized maxillary record bases were fabricated with seven reference points: Point A - Incisive papilla, Point B & C - Canine region on either side, Point E & G - Midpoint of tuberosities on either side, Point F- Midpoint of the line joining the two tuberosities, Point D- Midpoint between the line joining A and F. Group A: Ten maxillary record bases were fabricated by conventional clamping method and cured by long curing cycle. Group A1: Ten maxillary record bases were fabricated by R.S tension clamping method and cured by long curing cycle. Group B: Ten maxillary record bases were fabricated by conventional clamping method and cured by short curing cycle. Group B1: Ten maxillary record bases were fabricated by R.S tension clamping method and cured by short curing cycle. The distances between the reference points i.e. A-B, A-C, A-D, D-F, B-E, C-G, E-F, F-G, B-D, D-G, CD, D-E of all three thermoplastic denture base plates were measured and recorded with the help of a travelling microscope and were used for comparison with the measured and recorded readings of processed acrylic denture bases. The data obtained was analyzed by using the One Way Analysis of Variance. Results: The overall results of the in vitro study indicate that among all the PMMA bases cured by the two clamping systems and the different curing cycle, group A` was the most dimensionally stable, followed by control group A, then followed by B` and B was most unstable. Conclusion: The study concluded that the denture bases fabricated by the R.S Technique using the long curing cycle would produce the most dimensionally stable PMMA denture bases. How to cite the article: Babu MR, Rao CS, Ahmed ST, Bharat JS, Rao NV, Vinod V. A comparative evaluation of the dimensional accuracy of heat polymerised PMMA denture base cured by different curing cycles and clamped by R S technique and conventional method – An In-vitro study. J Int Oral Health 2014;6(2):68-75. PMID:24876705

Babu, Mandava Ramesh; Rao, C Satyanageswar; Ahmed, Syed Tauqheer; Bharat, J S V; Rao, N Venugopal; Vinod, V

2014-01-01

354

The effect of mechanical and chemical polishing techniques on the surface roughness of heat-polymerized and visible light-polymerized acrylic denture base resins  

PubMed Central

Objective The purpose of this study was to compare the effects of mechanical polishing (MP) and chemical polishing (CP) on the average surface roughness (Ra) of heat-cured (HC) and light-cured (LC) denture base acrylic resins. Methods A total of 120 specimens (30 × 15 × 3 mm) were prepared from one HC and one LC acrylic resin. To remove nodules and gross surface irregularities, all specimens were finished with a lathe-mounted small acrylic bur and 360-grit sandpaper. Ten finished specimens of each acrylic resin were randomly assigned to each of six polishing techniques: Resilit High-luster Polishing Liquid (RHPL), Universal Polishing Paste, Abraso-star K50, pumice, Jet Seal Liquid, or Acrypoint. MP was performed with an automatic polishing machine for 2 min, under 50 rpm and 500 g of load. CP was performed by immersing the HC and LC specimens in preheated methyl methacrylate at 75 ± 1 °C for 10 s. The surface roughness of the acrylic resin specimens was measured with a contact profilometer. The Ra values were analyzed by two-way analysis of variance, post hoc Scheffe's test, and paired t-test (p ? 0.05). Polished and tested acrylic resin surfaces were evaluated by scanning electron microscopy. Results MP was more effective than CP. The smoothest surface was obtained with the use of the RHPL on the LC (0.05 ± 0.01 ?m) or HC (0.07 ± 0.01 ?m) acrylic resin. Two-way ANOVA showed a statistically significant difference between MP and CP. Conclusions MP produced the smoothest surface of denture base acrylic resin. The mean surface roughness values after MP and CP were not influenced by the type of acrylic resin. PMID:25408597

Al-Kheraif, Abdul Aziz Abdullah

2014-01-01

355

Effect of adhesive primers on bonding strength of heat cure denture base resin to cast titanium and cobalt-chromium alloy  

PubMed Central

STATEMENT OF PROBLEM The poor chemical bonding of a denture base resin to cast titanium framework often introduces adhesive failure and increases microleakage. PURPOSE This study evaluated the shear bond strengths of a heat cure denture base resin to commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy using two adhesive primers. MATERIAL AND METHODS Disks of commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy were cast. Specimens without the primer were also prepared and used as the controls. The shear bond strengths were measured on a screw-driven universal testing machine. RESULTS The primers significantly (P < .05) improved the shear bond strengths of the heat cure resin to all metals. However, the specimens primed with the Alloy primer® (MDP monomer) showed higher bond strength than those primed with the MR bond® (MAC-10 monomer) on titanium. Only adhesive failure was observed at the metal-resin interface in the non-primed specimens, while the primed specimens showed mixed failure of adhesive and cohesive failure. CONCLUSIONS The use of appropriate adhesive metal primers makes it possible not only to eliminate the need for surface preparation of the metal framework before applying the heat cure resins, but also reduce the need for retentive devices on the metal substructure. In particular, the Alloy primer®, which contains the phosphoric acid monomer, MDP, might be clinically more acceptable for bonding a heat cure resin to titanium than a MR bond®, which contains the carboxylic acid monomer, MAC-10. PMID:21165254

Kim, Su-Sung; Yang, Hong-So; Park, Sang-Won; Lim, Hyun-Pil

2009-01-01

356

Analysis of stress on mucosa and basal bone underlying complete dentures with different reliner material thicknesses: a three-dimensional finite element study.  

PubMed

The aim of this study was to determine the optimal thickness of reliner material that provides the least amount of stress on thin mucosa and supporting bone in patients with complete removable dentures using a three-dimensional finite element analyses. The model was obtained from two CT scans of edentulous mandibles with dentures supported by the alveolar ridge. After virtual reconstruction, the three-dimensional models were exported to the solidworks cad software and divided into six groups based on the thickness of the reliner material as follows: (i) without material, (ii) 0·5 mm, (iii) 1 mm, (iv) 1·5 mm, (v) 2 mm and (vi) 2·5 mm. The applied load was 60 N and perpendicular to the long axis of the alveolar ridge of all the prosthetic teeth, and the mucosal thickness used was 1 mm. The analyses were based on the maximum principal stress in the fibromucosa and the minimum principal stress in the basal bone. Stress concentration was observed in the anterior zone of the mandible in the mucosa and in the bone. The maximum and minimum principal stress in the mucosa and bone, respectively, decreased, whereas the thickness of the reliner material increased until 2 mm, which transmitted the lowest stress, compared with the control. Reliner materials with a thickness of 2·5 mm showed higher stress values than those with a thickness of 2 mm. In conclusion, reliner material with a thickness of 2 mm transmitted the lowest amount of stress to the mucosa and bone in 1 mm of mucosa thickness. PMID:23889677

Lima, J B G; Orsi, I A; Borie, E; Lima, J H F; Noritomi, P Y

2013-10-01

357

C++ Templates as Partial Evaluation  

Microsoft Academic Search

This paper explores the relationship between C++ templates and partial evaluation. Templates were designed to support generic programming, but unintentionally provided the ability to perform compile-time computations and code generation. These features are completely accidental, and as a result their syntax is awkward. By recasting these features in terms of partial evaluation, a much simpler syntax can be achieved. C++

Todd L. Veldhuizen

1999-01-01

358

Partial confinement photonic crystal waveguides  

SciTech Connect

One-dimensional photonic crystal waveguides with an incomplete photonic band gap are modeled and proposed for an integration application that exploits their property of partial angular confinement. Planar apodized photonic crystal structures are deposited by plasma enhanced chemical vapor deposition and characterized by reflectivity as a function of angle and polarization, validating a partial confinement design for light at 850 nm wavelength. Partial confinement identifies an approach for tailoring waveguide properties by the exploitation of conformal film deposition over a substrate with angularly dependent topology. An application for an optoelectronic transceiver is demonstrated.

Saini, S.; Hong, C.-Y.; Pfaff, N.; Kimerling, L. C.; Michel, J. [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2008-12-29

359

Partial belief and expert testimony  

E-print Network

My dissertation investigates two questions from within a partial belief framework: First, when and how should deference to experts or other information sources be qualified? Second, how closely is epistemology related to ...

Briggs, Rachael (Rachael Amy)

2009-01-01

360

76 FR 4601 - Determinations Concerning Need for Error Correction, Partial Approval and Partial Disapproval...  

Federal Register 2010, 2011, 2012, 2013, 2014

...Partial Approval and Partial Disapproval, and Federal...for Error Correction, Partial Approval and Partial Disapproval, and Federal...information. Instructions. Direct your comments to Docket...know your identity or contact information unless...

2011-01-26

361

Are `Partial Cones' Aberrated Cones?  

NASA Astrophysics Data System (ADS)

`Partial cones' are classified as pulsars where the steepest gradient (SG) of the polarization-position angle (PPA) traverse lies towards one edge of the pulse profile. Here we present single pulse polarimetric observations of various `partial cones' observed with the Giant Meterwave Radio Telescope (GMRT) and the Arecibo Observatory(AO). We find several interesting emission properties for this class of pulsars: (a) in some cases we find sudden flarings where the dimmer part of the pulse profile becomes brighter; (b) We see evidence for drifting, signifying that the emission from this pulsar is possibly centered around the magnetic axis; and (c) the SG of the PPA tends to be towards the trailing edge of the profile. We conclude that the emission properties of partial cones are consistent with the relativistic beaming model of BCW, where the lagging PA traverse with respect to the total intensity profile is a natural prediction of the model.

Mitra, Dipanjan; Rankin, Joanna M.; Sarala, S.

2008-02-01

362

Full and partial gauge fixing  

SciTech Connect

Gauge fixing may be done in different ways. We show that using the chain structure to describe a constrained system enables us to use either a full gauge, in which all gauged degrees of freedom are determined, or a partial gauge, in which some first class constraints remain as subsidiary conditions to be imposed on the solutions of the equations of motion. We also show that the number of constants of motion depends on the level in a constraint chain in which the gauge fixing condition is imposed. The relativistic point particle, electromagnetism, and the Polyakov string are discussed as examples and full or partial gauges are distinguished.

Shirzad, A. [Institute for Studies in Theoretical Physics and Mathematics, P. O. Box 5531, Tehran 19395 (Iran, Islamic Republic of) and Department of Physics, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

2007-08-15

363

Marginal fit of anterior 3-unit fixed partial zirconia restorations using different CAD/CAM systems  

PubMed Central

PURPOSE Few studies have investigated the marginal accuracy of 3-unit zirconia fixed partial dentures (FPDs) fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) system. The purpose of this study was to compare the marginal fit of zirconia FPDs made using two CAD/CAM systems with that of metal-ceramic FPDs. MATERIALS AND METHODS Artificial resin maxillary central and lateral incisors were prepared for 3-unit FPDs and fixed in yellow stone. This model was duplicated to epoxy resin die. On the resin die, 15 three-unit FPDs were fabricated per group (45 in total): Group A, zirconia 3-unit FPDs made with the Everest system; Group B, zirconia 3-unit FPDs made with the Lava system; and Group C, metal-ceramic 3-unit FPDs. They were cemented to resin dies with resin cement. After removal of pontic, each retainer was separated and observed under a microscope (Presize 440C). Marginal gaps of experimental groups were analyzed using one-way ANOVA and Duncan test. RESULTS Mean marginal gaps of 3-unit FPDs were 60.46 µm for the Everest group, 78.71 µm for the Lava group, and 81.32 µm for the metal-ceramic group. The Everest group demonstrated significantly smaller marginal gap than the Lava and the metal-ceramic groups (P<.05). The marginal gap did not significantly differ between the Lava and the metal-ceramic groups (P>.05). CONCLUSION The marginal gaps of anterior 3-unit zirconia FPD differed according to CAD/CAM systems, but still fell within clinically acceptable ranges compared with conventional metal-ceramic restoration. PMID:24049561

Song, Tae-Jin; Kwon, Taek-Ka; Han, Jung-Suk; Lee, Jai-Bong; Kim, Sung-Hun

2013-01-01

364

MOMENTUM LIQUIDATION UNDER PARTIAL INFORMATION  

E-print Network

MOMENTUM LIQUIDATION UNDER PARTIAL INFORMATION ERIK EKSTR¨OM1 AND MARTIN VANNEST°AL Abstract information show that the assumption that the disappearance of the momentum effect is triggered by observable that performed well in the past typically continue to yield positive returns on a relatively short time horizon

Ekström, Erik

365

Designing a partially reconfigured system  

NASA Astrophysics Data System (ADS)

Partial reconfiguration is the ability of certain FPGAs to reconfigure only selected protions of the device while other portions contiue to operate undisturbed. When used in conjunction with the runtime reconfiguration (RTR) implementation strategy, the performance of the system can be greatly enhanced. RRANN2 is a RTR artifical neural network that uses partial reconfiguration. Its operation is divided into a series of sequentially executed stages with each stage implemented as a separate circuit module. System operation consists of sequencing through these modules at runtime, one configuraiton at a time. By carefully organizing each circuit module in order to establish a large number of functional and physical commonalities, partial reconfiguration is used to leave common circuitry resident on the FPGAs during system reconfiguration. Transitioning between configurations can then be accomplished by updating only the differences between circuit modules. This significantly enhances overall performance by reducing the amount of time the RTR application spends configuring. RRANN2 exhibited a 53.5% reduction in reconfiguration time through the use of partial reconfiguration. This paper presents the methodology used to design the RRANN2 system.

Hadley, J. D.; Hutchings, Brad L.

1995-09-01

366

Partially molten magma ocean model  

SciTech Connect

The properties of the lunar crust and upper mantle can be explained if the outer 300-400 km of the moon was initially only partially molten rather than fully molten. The top of the partially molten region contained about 20% melt and decreased to 0% at 300-400 km depth. Nuclei of anorthositic crust formed over localized bodies of magma segregated from the partial melt, then grew peripherally until they coverd the moon. Throughout most of its growth period the anorthosite crust floated on a layer of magma a few km thick. The thickness of this layer is regulated by the opposing forces of loss of material by fractional crystallization and addition of magma from the partial melt below. Concentrations of Sr, Eu, and Sm in pristine ferroan anorthosites are found to be consistent with this model, as are trends for the ferroan anorthosites and Mg-rich suites on a diagram of An in plagioclase vs. mg in mafics. Clustering of Eu, Sr, and mg values found among pristine ferroan anorthosites are predicted by this model.

Shirley, D.N.

1983-02-15

367

Partially implantable vibrating ossicular prosthesis  

Microsoft Academic Search

A partially implantable hearing prosthesis for sensorineural hearing loss patients has been developed using a novel electromagnetic actuator. The system is designed to couple acoustic frequency, vibrational energy into the ossicular structure of the middle ear. The complete system includes external signal processing and a transdermal telemetry system. The focus of this paper is to describe the transducer used to

Timothy G. Dietz; Geoffrey R. Ball; Bob H. Katz

1997-01-01

368

Partial Restriction Digests Leslie Vosshall  

E-print Network

of possible restriction sites for a given enzyme. · Method: A fixed amount of DNA will be cutPartial Restriction Digests 4/18/2001 Leslie Vosshall · Purpose: To generate DNA cut at a subset with progressively less enzyme for a fixed period of time (1 hour). Set up 6 tubes with the following components 2 ug

369

Partial discharge resistant enameled wire  

Microsoft Academic Search

Accompanied with the prevalence of motors controlled by the inverter, the problem of surge voltage arising from the inverter has become intensified. The high frequency components of the inverter switching pulse voltage lead to the overvoltages due to the impedance of the cable between the inverter and the motor, and the insulating materials have been damaged by the partial discharges.

T. Ozaki; T. Imai; F. Sawa; T. Shimizu; F. Kanemitsu

2005-01-01

370

The effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced acrylic resin denture base material on oral epithelial cells and fibroblasts.  

PubMed

Acrylic resin dentures may have cytotoxic effects on oral soft tissues. However, there is sparse data about the cytotoxic effect of fibre-reinforced acrylic resin denture base materials. The purpose of this in vitro study was to determine the effect of two fibre impregnation methods on the cytotoxicity of a glass and carbon fibre-reinforced heat-polymerized acrylic resin denture base material on oral epithelial cells and fibroblasts. One hundred acrylic resin discs were assigned to five experimental groups (n = 20). One of the groups did not include any fibre. Two groups consisted of silane and monomer treated glass fibres (Vetrolex) impregnated into acrylic resin (QC-20) discs. The other two groups consisted of silane and monomer treated carbon fibres (Type Tenox J, HTA). Untreated cell culture was used as positive control. The human oral epithelial cell line and buccal fibroblast cultures were exposed to test specimens. The cytotoxicity of the test materials was determined by succinic dehydrogenase activity (MTT method) after 24 and 72 h exposures. Data were analysed with a statistical software program (SPSSFW, 9.0). A one-way analysis of variance (anova) test and Bonferroni test were used for the comparisons between the groups. All statistical tests were performed at the 0.95 confidence level (P < 0.05). After 24 and 72 h incubation, cell viability percentages of all experimental groups showed significant decrease according to the positive control cell culture. Fibroblastic cell viability percentages of silane and monomer treated fibre-reinforced groups were lower than the unreinforced group. Cell viability of monomer-treated groups displayed the lowest percentages. Elapsed incubation time decreased epithelial cell viability in silane-treated groups. Fibroblastic cell viability was not influenced by elapsed time except the unreinforced group. PMID:16922740

Sipahi, Cumhur; Ozen, Julide; Ural, A Ugur; Dalkiz, Mehmet; Beydemir, Bedri

2006-09-01

371

Complex partial seizures in adults  

Microsoft Academic Search

Opinion statement  \\u000a \\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a Many disorders can mimic complex partial seizure (CPS), and clinicians must be careful to make an accurate diagnosis. Complex\\u000a partial seizures must be distinguished from generalized-onset seizures (such as absence seizures), which require a different\\u000a treatment regimen.\\u000a \\u000a \\u000a \\u000a \\u000a – \\u000a \\u000a Treatment of CPS should begin with monotherapy with a standard antiepileptic drug (AED), such as phenytoin or carbamazepine.\\u000a \\u000a \\u000a \\u000a \\u000a – 

Michael D. Privitera; Jerzy P. Szaflarski

1999-01-01

372

Partial domain wall partition functions  

NASA Astrophysics Data System (ADS)

We consider six-vertex model configurations on an ( n × N) lattice, n ? N, that satisfy a variation on domain wall boundary conditions that we define and call partial domain wall boundary conditions. We obtain two expressions for the corresponding partial domain wall partition function, as an ( N × N)-determinant and as an ( n × n)-determinant. The latter was first obtained by I Kostov. We show that the two determinants are equal, as expected from the fact that they are partition functions of the same object, that each is a discrete KP ?-function, and, recalling that these determinants represent tree-level structure constants in N = 4{SYM} , we show that introducing 1-loop corrections, as proposed by N Gromov and P Vieira, preserves the determinant structure.

Foda, O.; Wheeler, M.

2012-07-01

373

Partial Conway and iteration semirings  

E-print Network

A Conway semiring is a semiring $S$ equipped with a unary operation $^*:S \\to S$, always called 'star', satisfying the sum star and product star identities. It is known that these identities imply a Kleene type theorem. Some computationally important semirings, such as $N$ or $N^{\\rat}\\llangle \\Sigma^* \\rrangle$ of rational power series of words on $\\Sigma$ with coefficients in $N$, cannot have a total star operation satisfying the Conway identities. We introduce here partial Conway semirings, which are semirings $S$ which have a star operation defined only on an ideal of $S$; when the arguments are appropriate, the operation satisfies the above identities. We develop the general theory of partial Conway semirings and prove a Kleene theorem for this generalization.

Bloom, S L; Kuich, W

2007-01-01

374

Microflora of partially processed lettuce.  

PubMed Central

Bacteria, yeasts, and molds isolated from partially processed iceberg lettuce were taxonomically classified. The majority of bacterial isolates were gram-negative rods. Pseudomonas, Erwinia, and Serratia species were commonly found. Yeasts most frequently isolated from lettuce included members of the genera Candida, Cryptococcus, Pichia, Torulaspora, and Trichosporon. Comparatively few molds were isolated; members of the genera Rhizopus, Cladosporium, Phoma, Aspergillus, and Penicillium were identified. PMID:2082830

Magnuson, J A; King, A D; Török, T

1990-01-01

375

Tree reconstruction from partial orders  

SciTech Connect

The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n[sup 3]) time and from POM experiments in O(n[sup 4]) time.

Kannan, S.K. (Arizona Univ., Tucson, AZ (United States)); Warnow, T.J. (Sandia National Labs., Albuquerque, NM (United States))

1993-01-01

376

Tree reconstruction from partial orders  

SciTech Connect

The problem of constructing trees given a matrix of interleaf distances is motivated by applications in computational evolutionary biology and linguistics. The general problem is to find an edge-weighted tree which most closely approximates the distance matrix. Although the construction problem is easy when the tree exactly fits the distance matrix, optimization problems under all popular criteria are either known or conjectured to be NP-complete. In this paper we consider the related problem where we are given a partial order on the pairwise distances, and wish to construct (if possible) an edge-weighted tree realizing the partial order. In particular we are interested in partial orders which arise from experiments on triples of species, which determine either a linear ordering of the three pairwise distances (called Total Order Model or TOM experiments) or only the pair(s) of minimum distance apart (called Partial Order Model or POM experiments). The POM and TOM experimental model is inspired by the model proposed by Kannan, Lawler, and Warnow for constructing trees from experiments which determine the rooted topology for any triple of species. We examine issues of construction of trees and consistency of TOM and POM experiments, where the trees may either be weighted or unweighted. Using these experiments to construct unweighted trees without nodes of degree two is motivated by a similar problem studied by Winkler, called the Discrete Metric Realization problem, which he showed to be strongly NP-hard. We have the following results: Determining consistency of a set of TOM or POM experiments is NP-Complete whether the tree is weighted or constrained to be unweighted and without degree two nodes. We can construct unweighted trees without degree two nodes from TOM experiments in optimal O(n{sup 3}) time and from POM experiments in O(n{sup 4}) time.

Kannan, S.K. [Arizona Univ., Tucson, AZ (United States); Warnow, T.J. [Sandia National Labs., Albuquerque, NM (United States)

1993-03-01

377

Supersymmetric partially interacting dark matter  

NASA Astrophysics Data System (ADS)

We present a model of partially interacting dark matter within the framework of supersymmetry with gauge mediated symmetry breaking. Dark sector atoms are produced through Affleck-Dine baryogenesis in the dark sector while avoiding the production of Q -ball relics. We discuss the astrophysical constraints relevant for this model and the possibility of dark galactic disk formation. In addition, jet emission from rotating black holes is discussed in the context of this class of models.

Fischler, Willy; Lorshbough, Dustin; Tangarife, Walter

2015-01-01

378

Loosening torque of prosthetic screws in metal-ceramic or metal-acrylic resin implant-supported dentures with different misfit levels.  

PubMed

The aim of this study was to evaluate the effect of the prosthesis material (metal-acrylic resin or metal-ceramic) on loosening torque of the prosthetic screws in an implant-supported mandibular denture under two levels of vertical misfit. Ten frameworks were fabricated with commercially pure titanium, and five of them received acrylic resin and acrylic artificial teeth as veneering material and the other five were veneered with porcelain. Two levels of vertical fit were also created by fabricating 20 cast models to obtain four experimental groups according to the prosthesis material and misfit: Group 1 (metal-acrylic resin prosthesis with a passive fit); Group 2 (metal-acrylic resin prosthesis with a non-passive fit); Group 3 (metal-ceramic prosthesis with a passive fit); and Group 4 (metal-ceramic prosthesis with a non-passive fit). Two hundred prosthetic titanium-alloy screws were divided in 40 sets (five screws per set, n=10). After 24h, the loosening torque of the screws was evaluated using a digital torque meter. The results were submitted to two-way ANOVA analysis of variance followed by a Tukey's test (?=0.05). The mean values and standard deviations for each group were G1=7.05 (1.64), G2=5.52 (0.90), G3=6.46 (1.34), and G4=4.35 (0.99). Overall, the prosthesis material and misfit factors showed a statistically significant influence on the loosening torque (p<0.05). Metal-ceramic prosthesis and misfits decreased the loosening of the torque of the prosthetic screws. PMID:23477791

Bacchi, Ataís; Paludo, Litiane; Ferraz Mesquita, Marcelo; Schuh, Christian; Federizzi, Leonardo; Oro Spazzin, Aloísio

2013-04-26

379

The residual edentulous arches--foundation for implants and for removable dentures; some clinical considerations. A review of the literature 1954-2012.  

PubMed

The maxillary and mandibular arches are present before tooth eruption and will develop and mature with tooth activities. Following tooth extraction, the healing wound fills in, partly, the space occupied formerly by the natural tooth. The blood coagulum that occupies the healing wound will be replaced by the residual ridge, a scar tissue, which becomes part of the edentulous arch. After tooth loss, the resulting edentulous arches undergo extensive remodeling changes, but remain indispensable, vital oral structures. The resorptive process of the edentulous jaws is limited. The maxillary and mandibular bodies have never been known to recede completely. Furthermore, physiological spontaneous fracture of the jaws does not occur. One factor that helps preserve the jaws' integrity may be the enveloping muscle girdle attached to the external surfaces of the jawbones. The residual ridge develops after tooth extraction and continues to remodel, during the edentulous life of the individual. The ridge resorption is a chronic, progressive, irreversible process. The residual ridge may even disappear as an anatomic entity following an extended edentulous period, systemic and/or local factors. Resorption of the residual tissues seems to be hastened by, systemic affections, edentulousness time, denture wear, tobacco consumption and other unknown factors. In the edentulous patient, the maxillary ridge migration is centripetal and apical, whereas in the mandible, the remaining ridge shifts centrifugally and apically. Consequently the resulting edentulous maxillary arch is, mostly, internal or at the same vertical level with the facing toothless mandibular arch. The different individual inter arch spatial relations are to be considered for the positioning of the artificial teeth, for optional ridge augmentation procedures and for insertion of dental implants. PMID:23697296

Pietrokovski, J

2013-01-01

380

Preferential attachment with partial information  

NASA Astrophysics Data System (ADS)

We propose a preferential attachment model for network growth where new entering nodes have a partial information about the state of the network. Our main result is that the presence of bounded information modifies the degree distribution by introducing an exponential tail, while it preserves a power law behaviour over a finite small range of degrees. On the other hand, unbounded information is sufficient to let the network grow as in the standard Barabási-Albert model. Surprisingly, the latter feature holds true also when the fraction of known nodes goes asymptotically to zero. Analytical results are compared to direct simulations.

Carletti, Timoteo; Gargiulo, Floriana; Lambiotte, Renaud

2015-01-01

381

QoS enhancement with partial state  

E-print Network

@OS ENHANCEMENT WITH PARTIAL STATE A Thesis by DEYING TONG Submitted to the Office of Graduate Studies of Texas ASM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1999 Major Subject...: Electrical Engineering @OS ENHANCEMENT WITH PARTIAL STATE A Thesis by DEYING TONG Submitted to Texas ASM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved as to style and content by: A. L. N. Reddy...

Tong, Deying

2012-06-07

382

Partial Symmetry Breaking Iain McDonald  

E-print Network

Partial Symmetry Breaking Iain McDonald University of St Andrews, Fife, Scotland, iain@dcs.st-and.ac.uk Abstract. In this paper I de#12;ne partial symmetry breaking, a concept that has been used in many previous of partial symmetry breaking in constraint programming. I show experimentally that performing symmetry

Rossi, Francesca

383

Adult Partial Hospitalization JOHN DEMPSEY HOSPITAL  

E-print Network

." The Adult Partial Hospitalization Program is a day treatment program specifically designed for the diagnosisAdult Partial Hospitalization Program JOHN DEMPSEY HOSPITAL CONTACT US For further information.uchc.edu. The Adult Partial Hospitalization Program is available Monday through Friday from 9 a.m. to 2:05 p.m. OUR

Oliver, Douglas L.

384

Partial ACL rupture: an MR diagnosis?  

Microsoft Academic Search

Purpose. We sought to clarify the ability of magnetic resonance imaging (MR) to show partial ante- rior cruciate ligament (ACL) ruptures and to allow dis- tinction of partial from complete ACL ruptures. Materials and methods. Eighty-eight patients were stud- ied by arthroscopy and MR (36 with normal ACLs, 21 with partial ACL ruptures, and 31 with complete ACL ruptures). MR

Lawrence Yao; Amilcare Gentili; Leonard Petrus; Joong K. Lee

1995-01-01

385

Partial Wave Analysis at BESIII  

E-print Network

The BESIII experiment in Beijing takes data in $\\tau$-charm domain since 2009. For the moment the world largest samples of $J/\\psi$, $\\psi(3686)$, $\\psi(3770)$ and $\\psi(4040)$ data have been collected. Hadron spectroscopy is a unique way to access QCD, which is one of the most important physics goals of BESIII. Experimental search of new forms of hadrons and subsequent investigation of their properties would provide validation of and valuable input to the quantitative understanding of QCD. The key to success lies in high levels of precision during the measurement and high statistics in the recorded data set complemented with sophisticated analysis methods. Partial wave analysis (PWA) is a powerful tool to study the hadron spectroscopy, that allows one to extract the resonance's spin-parity, mass, width and decay properties with high sensitivity and accuracy. In this poster, we present the working PWA framework of BESIII -- GPUPWA and the recent results of PWA of $J/\\psi\\to\\gamma\\eta\\eta$. GPUPWA is a PWA framework for high statistics partial wave analyses harnessing the GPU parallel computing.

Beijiang Liu

2014-03-06

386

Partial Return Yoke for MICE  

SciTech Connect

The international Muon Ionization Cooling Experiment (MICE) is a large scale experiment which is presently assembled at the Rutherford Appleton Laboratory in Didcot, UK. The purpose of MICE is to demonstrate the concept of ionization cooling experimentally. Ionization cooling is an important accelerator concept which will be essential for future HEP experiments such as a potential Muon Collider or a Neutrino Factory. The MICE experiment will house up to 18 superconducting solenoids, all of which produce a substantial amount of magnetic flux. Recently it was realized that this magnetic flux leads to a considerable stray magnetic field in the MICE hall. This is a concern as technical equipment in the MICE hall may may be compromised by this. In July 2012 a concept called partial return yoke was presented to the MICE community, which reduces the stray field in the MICE hall to a safe level. This report summarizes the general concept, engineering considerations and the expected shielding performance.

Witte H.; Plate, S; ,

2013-05-03

387

Partial control of chaotic systems.  

PubMed

In a region in phase space where there is a chaotic saddle, all initial conditions will escape from it after a transient with the exception of a set of points of zero Lebesgue measure. The action of an external noise makes all trajectories escape faster. Attempting to avoid those escapes by applying a control smaller than noise seems to be an impossible task. Here we show, however, that this goal is indeed possible, based on a geometrical property found typically in this situation: the existence of a horseshoe. The horseshoe implies that there exist what we call safe sets, which assures that there is a general strategy that allows one to keep trajectories inside that region with control smaller than noise. We call this type of control partial control of chaos. PMID:18643119

Zambrano, Samuel; Sanjuán, Miguel A F; Yorke, James A

2008-05-01

388

Modeling Partial Attacks with Alloy  

NASA Astrophysics Data System (ADS)

The automated and formal analysis of cryptographic primitives, security protocols and Application Programming Interfaces (APIs) up to date has been focused on discovering attacks that completely break the security of a system. However, there are attacks that do not immediately break a system but weaken the security sufficiently for the adversary. We term these attacks partial attacks and present the first methodology for the modeling and automated analysis of this genre of attacks by describing two approaches. The first approach reasons about entropy and was used to simulate and verify an attack on the ECB|ECB|OFB triple-mode DES block-cipher. The second approach reasons about possibility sets and was used to simulate and verify an attack on the personal identification number (PIN) derivation algorithm used in the IBM 4758 Common Cryptographic Architecture.

Lin, Amerson; Bond, Mike; Clulow, Jolyon

389

Partially coherent lensfree tomographic microscopy?  

PubMed Central

Optical sectioning of biological specimens provides detailed volumetric information regarding their internal structure. To provide a complementary approach to existing three-dimensional (3D) microscopy modalities, we have recently demonstrated lensfree optical tomography that offers high-throughput imaging within a compact and simple platform. In this approach, in-line holograms of objects at different angles of partially coherent illumination are recorded using a digital sensor-array, which enables computing pixel super-resolved tomographic images of the specimen. This imaging modality, which forms the focus of this review, offers micrometer-scale 3D resolution over large imaging volumes of, for example, 10–15 mm3, and can be assembled in light weight and compact architectures. Therefore, lensfree optical tomography might be particularly useful for lab-on-a-chip applications as well as for microscopy needs in resource-limited settings. PMID:22193016

Isikman, Serhan O.; Bishara, Waheb; Ozcan, Aydogan

2012-01-01

390

Representations of partial derivatives in thermodynamics  

NSDL National Science Digital Library

One of the mathematical objects that students become familiar with in thermodynamics, often for the first time, is the partial derivative of a multivariable function. The symbolic representation of a partial derivative and related quantities present difficulties for students in both mathematical and physical contexts, most notably what it means to keep one or more variables fixed while taking the derivative with respect to a different variable. Material properties are themselves written as partial derivatives of various state functions (e.g., compressibility is a partial derivative of volume with respect to pressure). Research in courses at the University of Maine and Oregon State University yields findings related to the many ways that partial derivatives can be represented and interpreted in thermodynamics. Research has informed curricular development that elicits many of the difficulties using different representations (e.g., geometric) and different contexts (e.g., connecting partial derivatives to specific experiments).

Thompson, John R.; Manogue, Corinne A.; Roundy, David J.; Mountcastle, Donald B.

2012-05-15

391

Quantum states with strong positive partial transpose  

SciTech Connect

We construct a large class of bipartite M x N quantum states which defines a proper subset of states with positive partial transposes (PPTs). Any state from this class has PPT but the positivity of its partial transposition is recognized with respect to canonical factorization of the original density operator. We propose to call elements from this class states with strong positive partial transposes (SPPTs). We conjecture that all SPPT states are separable.

Chruscinski, Dariusz; Jurkowski, Jacek; Kossakowski, Andrzej [Institute of Physics, Nicolaus Copernicus University, Grudziadzka 5/7, 87-100 Torun (Poland)

2008-02-15

392

20% PARTIAL SIBERIAN SNAKE IN THE AGS.  

SciTech Connect

An 11.4% partial Siberian snake was used to successfully accelerate polarized proton through a strong intrinsic depolarizing spin resonance in the AGS. No noticeable depolarization was observed. This opens up the possibility of using a 20% to 30% partial Siberian snake in the AGS to overcome all weak and strong depolarizing spin resonances. Some design and operation issues of the new partial Siberian snake are discussed.

Huang, H; Bai, M; Brown, K A; Glenn, W; Luccio, A U; Mackay, W W; Montag, C; Ptitsyn, V; Roser, T; Tsoupas, N; Zeno, K; Ranjbar, V; Spinka, H

2002-11-06

393

Partial equilibrium approximations in Apoptosis  

E-print Network

Apoptosis is one of the most basic biological processes. In apoptosis, tens of species are involved in many biochemical reactions with times scales of widely differing orders of magnitude. By the law of mass action, the process is mathematically described with a large and stiff system of ODEs (ordinary differential equations). The goal of this work is to simplify such systems of ODEs with the PEA (partial equilibrium approximation) method. In doing so, we propose a general framework of the PEA method together with some conditions, under which the PEA method can be justified rigorously. The main condition is the principle of detailed balance for fast reactions as a whole. With the justified method as a tool, we made many attempts via numerical tests to simplify the Fas-signaling pathway model due to Hua et al. (2005) and found that nine of reactions therein can be well regarded as relatively fast. This paper reports our simplification of Hua at el.'s model with the PEA method based on the fastness of the nine ...

Huang, Ya-Jing

2012-01-01

394

Partial Wave Analysis at BESIII  

E-print Network

The BESIII experiment in Beijing takes data in $\\tau$-charm domain since 2009. For the moment the world largest samples of $J/\\psi$, $\\psi(3686)$, $\\psi(3770)$ and $\\psi(4040)$ data have been collected. Hadron spectroscopy is a unique way to access QCD, which is one of the most important physics goals of BESIII. Experimental search of new forms of hadrons and subsequent investigation of their properties would provide validation of and valuable input to the quantitative understanding of QCD. The key to success lies in high levels of precision during the measurement and high statistics in the recorded data set complemented with sophisticated analysis methods. Partial wave analysis (PWA) is a powerful tool to study the hadron spectroscopy, that allows one to extract the resonance's spin-parity, mass, width and decay properties with high sensitivity and accuracy. In this poster, we present the working PWA framework of BESIII -- GPUPWA and the recent results of PWA of $J/\\psi\\to\\gamma\\eta\\eta$. GPUPWA is a PWA fra...

Liu, Beijiang

2014-01-01

395

Partially entangled states bridge in quantum teleportation  

NASA Astrophysics Data System (ADS)

The traditional method for information transfer in a quantum communication system using partially entangled state resource is quantum distillation or direct teleportation. In order to reduce the waiting time cost in hop-by-hop transmission and execute independently in each node, we propose a quantum bridging method with partially entangled states to teleport quantum states from source node to destination node. We also prove that the designed specific quantum bridging circuit is feasible for partially entangled states teleportation across multiple intermediate nodes. Compared to two traditional ways, our partially entanglement quantum bridging method uses simpler logic gates, has better security, and can be used in less quantum resource situation.

Cai, Xiao-Fei; Yu, Xu-Tao; Shi, Li-Hui; Zhang, Zai-Chen

2014-10-01

396

Evaporation from partially covered water surfaces  

Microsoft Academic Search

Evaporative losses from large water bodies may exceed 20% of water used in irrigated agriculture, with losses from reservoirs estimated at 50% of storage capacity. Prominent among proposed methods to curtail these evaporative losses are various forms of partial covers placed over water surfaces. Studies show that evaporation through perforated covers and from partially covered water surfaces exhibit nonlinear behavior,

S. Assouline; K. Narkis; D. Or

2010-01-01

397

Discovering Injective Episodes with General Partial Orders  

Microsoft Academic Search

Frequent episode discovery is a popular framework for temporal pattern discovery in event streams. An episode is a partially ordered set of nodes with each node associated with an event type. Currently algorithms exist for episode discovery only when the associated partial order is total order (serial episode) or trivial (parallel episode). In this paper, we propose efficient algorithms for

Avinash Achar; Srivatsan Laxman; Raajay Viswanathan; P. S. Sastry

2012-01-01

398

Nested hierarchical controller with partial autonomy  

NASA Technical Reports Server (NTRS)

The problem of computer architecture for intelligent robots with partial autonomy is addressed. A robot with partial autonomy is considered a degenerated case of a fully autonomous robot. Thus, the problem of man-machine communication is formulated, and the conditions are determined for generating a language for such a communication. The duties of the master are determined.

Meystel, A.

1987-01-01

399

Modular polynomial arithmetic in partial fraction decomposition  

NASA Technical Reports Server (NTRS)

Algorithms for general partial fraction decomposition are obtained by using modular polynomial arithmetic. An algorithm is presented to compute inverses modulo a power of a polynomial in terms of inverses modulo that polynomial. This algorithm is used to make an improvement in the Kung-Tong partial fraction decomposition algorithm.

Abdali, S. K.; Caviness, B. F.; Pridor, A.

1977-01-01

400

Partial cubes: structures, characterizations, and constructions  

E-print Network

Partial cubes: structures, characterizations, and constructions Sergei Ovchinnikov San Francisco cubes are isometric subgraphs of hypercubes. Structures on a graph defined by means of semicubes, and Djokovi´c's and Winkler's relations play an important role in the theory of partial cubes

Ovchinnikov, Sergei

401

Exploring Partial Order of European Countries  

ERIC Educational Resources Information Center

Partial Order Theory has been recently more and more employed in applied science to overcome the intrinsic disadvantage hidden in aggregation, if a multiple attribute system is available. Despite its numerous positive features, there are many practical cases where the interpretation of the partial order can be rather troublesome. In these cases…

Annoni, Paola; Bruggemann, Rainer

2009-01-01

402

Directivity Index of Partially Random Sonobuoy Arrays  

Microsoft Academic Search

The directivity index, DI, of partially random arrays is analyzed. A partially random array is an array in which the element positions are random variables subject to constraints that create some degree of either non-randomness or interdependence. The analysis is based on the definition of DI as the ratio in decibels of the power received by a single omnidirectional hydrophone

J. Thorn; N. Booth; J. Lockwood

1979-01-01

403

The Postself and Richard Nixon's Partial Death.  

ERIC Educational Resources Information Center

Correlates Nixon's actions during his final days in office to the concepts of postself and partial death. Postself is the image one wants to remain after death. Partial death is a transitory state in which one faces a major alteration in his/her relationship to the world. (JMF)

Nelson, Phillips

1980-01-01

404

Removable partial overdentures for the irradiated patient  

SciTech Connect

Patients who have received radiotherapy to the head and neck area must avoid dental extractions and seek simplicity in treatment and home care follow-up. For partially edentulous patients, removable partial overdenture therapy can fulfill these goals while maintaining the high level of function and aesthetics desired by patients.11 references.

Rosenberg, S.W. (New York Univ. School of Dentistry, NY (USA))

1990-10-01

405

ACTIONS AND PARTIAL ACTIONS OF INDUCTIVE CONSTELLATIONS  

E-print Network

ACTIONS AND PARTIAL ACTIONS OF INDUCTIVE CONSTELLATIONS VICTORIA GOULD AND CHRISTOPHER HOLLINGS Abstract. Constellations were recently introduced by the authors as one- sided analogues of categories: a constellation is equipped with a partial multi- plication for which `domains' are defined but, in general

Gould, Victoria

406

Consensus in the presence of partial synchrony  

Microsoft Academic Search

The concept of partial synchrony in a distributed system is introduced. Partial synchrony lies between the cases of a synchronous system and an asynchronous system. In a synchronous system, there is a known fixed upper bound ? on the time required for a message to be sent from one processor to another and a known fixed upper bound &PHgr; on

Cynthia Dwork; Nancy A. Lynch; Larry J. Stockmeyer

1988-01-01

407

Partial rupture of the distal biceps tendon.  

PubMed

Partial rupture of the distal biceps tendon is a relatively rare event, and various degrees of partial tendon tears have been reported. In the current study four patients with partial atraumatic distal biceps tendon tears (mean age, 59 years; range, 40-82 years) are reported. In all four patients, a common clinical pattern emerged. Pain at the insertion of the distal biceps tendon in the radius unrelated to any traumatic event was the main symptom. In all patients the diagnosis was based on magnetic resonance imaging or computed tomography imaging. In three of four patients the partial rupture of the tendon caused a significant bursalike lesion. The typical appearance was a partially ruptured biceps tendon, with contrast enhancement signaling the degree of degeneration, tenosynovitis, and soft tissue swelling extending along the tendon semicircular to the proximal radius. In three patients, conservative treatment was successful. Only one patient needed surgery, with reinsertion of the tendon resulting in total functional recovery. PMID:10818980

Dürr, H R; Stäbler, A; Pfahler, M; Matzko, M; Refior, H J

2000-05-01

408

Urinary fistulae after partial nephrectomy  

PubMed Central

Objective To report the risk factors and natural history of urinary fistula (UF) after partial nephrectomy (PN), as their incidence has been reported to be 3–6% in large series of PN but there are few reports of the risk factors associated with the development of UF after PN, and the natural history of UF in a large group of patients. Patients and Methods This was a retrospective review of 1118PN at one tertiary-care institution. Most patients had a drain placed in the perinephric space after surgery. Fifty-two patients were identified as having a UF if they had persistent flank drainage for >14 days after surgery, or presented with evidence of a UF after the drain had been removed. Risk factors for development and the course of the UF are reported. Results Fifty-two patients developed a UF after PN (4.4%, 95% confidence interval, CI, 3.5–6.1%) The rate of a persistent urine leak (defined as drain fluid consistent with urine for >2 weeks after surgery) was 4.0 (95% CI 2.9–5.3)%. The overall rate of delayed UF presentation was only 0.4 (0.09–0.9)%. Patients who developed a UF had larger tumours (3.5 vs 2.6cm, P = 0.03), a higher estimated blood loss (400 vs 300mL, P < 0.001), and longer ischaemia time (50 vs 39min, P < 0.001) than patients who did not develop a UF. Differences in tumour histology, laterality, multifocality, type of surgery (laparoscopic vs open), and intraoperative collecting system entry were not statistically different in patients who did or did not develop a UF. Patients with tumours of >2.5cm were twice as likely to develop a UF than patients with tumours of <2.5cm (P = 0.02). Most patients were managed conservatively with a percutaneous drain until the UF resolved, if they were asymptomatic. Overall, in 36 patients (69%) the fistula resolved with no intervention, while 16 (31%) required intervention. Stenting was the commonest intervention (15%). No patient required re-operative open surgery. Conclusion The rate of development of UF after PN is low. Tumour size, blood loss and ischaemia time were all associated with the development of a UF. In most patients with a urine leak immediately after surgery the UF will resolve with no intervention, and can be managed conservatively with patience, in the absence of clinical symptoms. PMID:20230384

Kundu, Shilajit D.; Thompson, R. Houston; Kallingal, George J.; Cambareri, Gina; Russo, Paul

2015-01-01

409

theory of partial differential equations a. zagaris Theory of Partial Differential Equations (155010)  

E-print Network

theory of partial differential equations a. zagaris Theory of Partial Differential Equations (155010) (Some) Prerequisites & (Numerous) Remarks antonios zagaris | university of twente Guidelines://ocw.mit.edu/courses/mathematics/18-03-differential-equations-spring-2006.) 1 #12;theory of partial differential equations a. zagaris

Al Hanbali, Ahmad

410

Oral health-related quality of life in partially edentulous patients before and after implant therapy: a 2-year longitudinal study  

PubMed Central

SUMMARY Objectives. The aim of this study was to measure the Oral Health-Related Quality of Life (OHRQoL) before and after a prosthodontic implant therapy so to determine the physical and psychological impact of implant-supported fixed partial dentures (IFPD) rehabilitation among edentulous patients. Methods. 50 partially edentulous patients aged 40–70 years, treated with IFPD, completed the OHRQoL questionnaire before the implant surgery (Time 0) and 2 years after their whole implant-prosthetic rehabilitation (Time 1). The questionnaire was proposed in a short version of Oral Health Impact Profile (OHIP-14, range 0–56) and analyzed through the ‘additive method’. We evaluated statistical mean, standard deviation, median, variance and mode of all OHIP-14 domains and the statistical significance about oral changes at Time 0 and Time 1 using the Chi-square test (p-values < 0.05). Results. Patients reported significant changes in mean OHIP scores (Time 0: 2.15; Time 1: 0.65; p < 0.01). The most prevalently affected domain was “functional limitation”, followed by “psychological discomfort” and “physical pain”. There were no significant differences dependent on age, gender and antagonistic teeth (p > 0.05). Patients with I and IV Kennedy’s class edentulism showed better improvement (p < 0.05). Conclusions. Preoperative and post-treatment assessments of OHRQoL exhibited significant differences. The IFPD treatment had a positive effect on the OHRQoL, which improved better in patients with I and IV Kennedy’s edentulous class. PMID:24175052

BRAMANTI, E.; MATACENA, G.; CECCHETTI, F.; ARCURI, C.; CICCIÙ, M.

2013-01-01

411

Fluctuation theorem for partially masked nonequilibrium dynamics  

NASA Astrophysics Data System (ADS)

We establish a generalization of the fluctuation theorem for partially masked nonequilibrium dynamics. We introduce a partial entropy production with a subset of all possible transitions, and show that the partial entropy production satisfies the integral fluctuation theorem. Our result reveals the fundamental properties of a broad class of autonomous as well as nonautonomous nanomachines. In particular, our result gives a unified fluctuation theorem for both autonomous and nonautonomous Maxwell's demons, where mutual information plays a crucial role. Furthermore, we derive a fluctuation-dissipation theorem that relates nonequilibrium stationary current to two kinds of equilibrium fluctuations.

Shiraishi, Naoto; Sagawa, Takahiro

2015-01-01

412

Partially decentralized control for ALSTOM gasifier.  

PubMed

The gasifier plays a key role in the operation of the whole IGCC power plant. It is a typical multivariable control system with strict constraints on the inputs and outputs which makes it very difficult to control. This paper presents a partially decentralized controller design method based on the stabilizer idea. The method only requires identifying some closed-loop transfer functions and solving an H(?) optimization problem. The final partially decentralized controller is easy to implement and test in practice. Two partially decentralized controllers are designed for the ALSTOM gasifier benchmark problem, and simulation results show that they both meet the design specifications. PMID:21356534

Tan, Wen; Lou, Guannan; Liang, Luping

2011-07-01

413

Circulant states with positive partial transpose  

SciTech Connect

We construct a large class of quantum dxd states which are positive under partial transposition (so called PPT states). The construction is based on certain direct sum decomposition of the total Hilbert space displaying characteristic circular structure - that is why we call them circulant states. It turns out that partial transposition maps any such decomposition into another one and hence both original density matrix and its partially transposed partner share similar cyclic properties. This class contains many well-known examples of PPT states from the literature and gives rise to a huge family of completely new states.

Chruscinski, Dariusz; Kossakowski, Andrzej [Institute of Physics, Nicolaus Copernicus University, GrudziaPdzka 5/7, 87-100 Torun (Poland)

2007-09-15

414

Method for partially coating laser diode facets  

NASA Technical Reports Server (NTRS)

Bars of integral laser diode devices cleaved from a wafer are placed with their p regions abutting and n regions abutting. A thin BeCu mask having alternate openings and strips of the same width as the end facets is used to mask the n region interfaces so that multiple bars can be partially coated over their exposed p regions with a reflective or partial reflective coating. The partial coating permits identification of the emitting facet from the fully coated back facet during a later device mounting procedure.

Dholakia, Anil R. (Inventor)

1990-01-01

415

Microscopic Examination of Stools After Partial Gastrectomy  

PubMed Central

The present study was undertaken to determine the frequency with which undigested meat fibres in the stool could be found after partial gastrectomy. A sample of stool was examined in 61 patients who had undergone a partial gastrectomy and in 92 control patients. The age ranges and average ages of both groups were similar. The stools of 77 of the 92 control patients contained well-digested meat fibres, 14 showed partially digested fibres, and one patient had completely undigested meat fibres. In the postgastrectomy group, 44 of 61 patients had well-digested meat fibres and 17 showed partially digested fibres in their stools. None showed undigested fibres. The present study demonstrated that the finding of undigested meat fibres is as infrequent in postgastrectomy patients as in control patients. If undigested meat fibres are found in the stools of postgastrectomy patients, it is suggestive of pancreatic exocrine insufficiency. ImagesFig. 2 PMID:5842594

Lowry, R. B.; Tamboline, B. L.; Bogoch, A.

1965-01-01

416

Partial Knee with Personalized Patient Care  

MedlinePLUS Videos and Cool Tools

Oxford® Partial Knee with Signature™ Personalized Patient Care You must have Javascript enabled in your web browser. View Program Transcript Click Here to view the OR-Live, Inc. Privacy Policy and ...

417

Accommodating blind and partially sighted clients  

PubMed Central

Veterinary surgeons provide an important service to blind and partially sighted guide dog owners. By adopting basic disability awareness and visual impairment training, practices can ensure that the assistance needs of those clients are met, facilitating access to veterinary care.

England, Gary; Gebbels, Tim; Whelan, Chantelle; Freeman, Sarah

2014-01-01

418

THE CASE FOR PARTIAL INDEXES Michael Stonebraker  

E-print Network

THE CASE FOR PARTIAL INDEXES Michael Stonebraker Department of Electrical Engineering and Computer by [VALD87] and to the links in System R [ASTR76]. However, it appears that few people have suggested

California at Irvine, University of

419

Decision Making with Partially Consonant Belief Functions  

E-print Network

This paper studies decision making for Walley’s partially consonant belief functions (pcb). In a pcb, the set of foci are partitioned. Within each partition, foci are nested. The pcb class includes probability and possibility ...

Giang, Phan H.; Shenoy, Prakash P.

2003-08-01

420

Nonlinear Elliptic Partial Difference Equations on Graphs  

Microsoft Academic Search

This article furthers the study of nonlinear elliptic partial difference equations (PdE) on graphs. We seek solutions {\\\\small $u:V\\\\to\\\\R$} to the semilinear elliptic partial difference equation {\\\\small $-Lu + f(u) = 0$} on a graph {\\\\small $G=(V,E)$}, where\\u000a{\\\\small $L$} is the (negative) Laplacian on the graph {\\\\small $G$}. We extend techniques used to prove existence theorems and derive numerical

John M. Neuberger

2006-01-01

421

Gingival enlargement in partial hemifacial hyperplasia  

PubMed Central

Hemifacial hypertrophy is a rare developmental disorder, characterized by unilateral enlargement of facial tissues. The hemifacial hyperplasia is classified as true hemifacial hypertrophy and partial hemifacial hypertrophy. It is unilateral enlargement of viscerocranial condition in which not all structures are enlarged. We present a rare case of gingival enlargement in partial hemifacial hyperplasia highlighting the clinical and radiological findings with the corrective treatment offered for gingival enlargement.

Jagtap, Rasika Ravindra; Deshpande, Gaurav Shekhar

2014-01-01

422

Partial conservation of seniority in nuclei  

E-print Network

A review is given of the relation between pairing, quasi-spin algebras and seniority. The former two concepts are closely connected, the relation being that the quasi-spin formalism allows an efficient solution of the pairing problem. Seniority is of much wider applicability than either pairing or quasi-spin and applications can even be extended to encompass the notion of partial symmetry. A recent application of partial conservation of seniority and its importance for nuclear isomers is discussed.

P. Van Isacker

2010-12-09

423

Partial nitrification under limited dissolved oxygen conditions  

Microsoft Academic Search

Partial nitrification to nitrite is technically feasible and economically favourable, especially when wastewaters contained high ammonium concentrations or low C\\/N ratios. Partial nitrification can be obtained by selectively inhibiting nitrite-oxidizing bacteria (NOB) through appropriate regulation of the pH, temperature and dissolved oxygen (DO) concentrations. The effect of pH, DO levels and temperature on ammonia oxidation rate and nitrite accumulation was

Wang Jianlong; Yang Ning

2004-01-01

424

Spreading paths in partially observed social networks  

PubMed Central

Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using a static, structurally realistic social network as a platform for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Although partial observation inflates the length of the shortest path, the stochastic nature of the spreading process also frequently derails the dynamic path from the shortest path. We find that the partially observed shortest path does not necessarily give an inflated estimate of the length of the process path; in fact, partial observation may, counterintuitively, make the path seem shorter than it actually is. PMID:22587148

Onnela, Jukka-Pekka; Christakis, Nicholas A.

2012-01-01

425

40 CFR 721.10146 - Partially fluorinated condensation polymer (generic).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Partially fluorinated condensation polymer (generic). 721.10146...721.10146 Partially fluorinated condensation polymer (generic). (a) Chemical...generically as partially fluorinated condensation polymer (PMN P-07-87) is...

2013-07-01

426

40 CFR 721.10146 - Partially fluorinated condensation polymer (generic).  

Code of Federal Regulations, 2014 CFR

...2014-07-01 false Partially fluorinated condensation polymer (generic). 721.10146...721.10146 Partially fluorinated condensation polymer (generic). (a) Chemical...generically as partially fluorinated condensation polymer (PMN P-07-87) is...

2014-07-01

427

40 CFR 721.10146 - Partially fluorinated condensation polymer (generic).  

Code of Federal Regulations, 2012 CFR

...2012-07-01 false Partially fluorinated condensation polymer (generic). 721.10146...721.10146 Partially fluorinated condensation polymer (generic). (a) Chemical...generically as partially fluorinated condensation polymer (PMN P-07-87) is...

2012-07-01

428

Cubic inflation, mirror graphs, regular maps, and partial cubes  

E-print Network

Cubic inflation, mirror graphs, regular maps, and partial cubes Bostjan Bresar University, partial cubes Mailing address: Bostjan Bresar, University of Maribor, FEECS, Smetanova 17, 2000 Maribor, Slovenia 2 #12;Abstract Partial cubes are, by definition, isometric subgraphs of hypercubes. Cubic

Klavzar, Sandi

429

Incremental fusion of partial biometric information  

NASA Astrophysics Data System (ADS)

Existing face recognition schemes are mostly based on extracting biometric feature vectors either from whole face images, or from a fixed facial region (e.g., eyes, nose, and mouth). Extreme variation in quality conditions between biometric enrolment and verification stages badly affects the performance of face recognition systems. Such problems have partly motivated several investigations into the use of partial facial features for face recognition. Nevertheless, partial face recognition is potentially useful in several applications, for instance, it used in forensics for detectives to identify individuals after some accidents such as fire or explosion. In this paper, we propose a scheme to fuse the biometric information of partial face images incrementally based on their recognition accuracy (or discriminative power) ranks. Such fusion scheme uses the optimal ratio of full/partial face images in each different quality condition. We found that such scheme is also useful for full face images to enhance authentication accuracy significantly. Nevertheless, it reduces the required storage requirements and processing time of the biometric system. Our experiments show that the required ratio of full/partial facial images to achieve optimal performance varies from (5%) to (80%) according to the quality conditions whereas the authentication accuracy improves significantly for low quality biometric samples.

Abboud, Ali J.; Jassim, Sabah A.

2012-06-01

430

Partial volume correction in quantitative amyloid imaging.  

PubMed

Amyloid imaging is a valuable tool for research and diagnosis in dementing disorders. As positron emission tomography (PET) scanners have limited spatial resolution, measured signals are distorted by partial volume effects. Various techniques have been proposed for correcting partial volume effects, but there is no consensus as to whether these techniques are necessary in amyloid imaging, and, if so, how they should be implemented. We evaluated a two-component partial volume correction technique and a regional spread function technique using both simulated and human Pittsburgh compound B (PiB) PET imaging data. Both correction techniques compensated for partial volume effects and yielded improved detection of subtle changes in PiB retention. However, the regional spread function technique was more accurate in application to simulated data. Because PiB retention estimates depend on the correction technique, standardization is necessary to compare results across groups. Partial volume correction has sometimes been avoided because it increases the sensitivity to inaccuracy in image registration and segmentation. However, our results indicate that appropriate PVC may enhance our ability to detect changes in amyloid deposition. PMID:25485714

Su, Yi; Blazey, Tyler M; Snyder, Abraham Z; Raichle, Marcus E; Marcus, Daniel S; Ances, Beau M; Bateman, Randall J; Cairns, Nigel J; Aldea, Patricia; Cash, Lisa; Christensen, Jon J; Friedrichsen, Karl; Hornbeck, Russ C; Farrar, Angela M; Owen, Christopher J; Mayeux, Richard; Brickman, Adam M; Klunk, William; Price, Julie C; Thompson, Paul M; Ghetti, Bernadino; Saykin, Andrew J; Sperling, Reisa A; Johnson, Keith A; Schofield, Peter R; Buckles, Virginia; Morris, John C; Benzinger, Tammie L S

2015-02-15

431

FAST TRACK COMMUNICATION: Statistics of partial minima  

NASA Astrophysics Data System (ADS)

We study pseudo-optimal solutions to multi-objective optimization problems by introducing partial minima defined as follows. Point x k-dominates x' when at least k of the coordinates of x are smaller than the corresponding coordinates of x'. A point not k-dominated by any other point in the set is a k-minimum or a partial minimum, generalizing the global minimum. We study statistical properties of partial minima for a set of N points independently distributed inside the d-dimensional unit hypercube using exact probabilistic methods and heuristic scaling techniques. The average number of partial minima, A, decays algebraically with the total number of points, A ~ N-(d-k)/k, when 1 <= k < d. Interestingly, there are k - 1 distinct scaling laws characterizing the largest coordinates: the distribution P(yj) of the jth largest coordinate, yj, decays algebraically, {P(y_j)\\sim (y_j)^{-\\alpha_j-1}} , with {\\alpha_j=j\\frac{d-k}{k-j}} for 1 <= j <= k - 1. The average number of partial minima grows logarithmically, {A\\simeq \\frac{1}{(d-1)!}(\\ln N)^{d-1}} , when k = d. The full distribution of the number of minima is obtained in closed form in two dimensions.

Ben-Naim, E.; Hastings, M. B.; Izraelevitz, D.

2007-11-01

432

Partial summary measures of the predictiveness curve  

PubMed Central

In the evaluation of a biomarker for risk prediction, one can assess the performance of the biomarker in the population of interest by displaying the predictiveness curve. In conjunction with an assessment of the classification accuracy of a biomarker, the predictiveness curve is an important tool for assessing the usefulness of a risk prediction model. Inference for a single biomarker or for multiple biomarkers can be performed using summary measures of predictiveness curve. We propose two partial summary measures, the partial total gain and the partial proportion of explained variation, that summarize the predictiveness curve over a restricted range of risk. The methods we describe can be used to compare two biomarkers when there are existing thresholds for risk stratification. We describe inferencial tools for one and two-samples that are shown to have adequate power in a simulation study. The methods are illustrated by assessing the accuracy of a risk score for predicting the onset of Alzheimer's Disease. PMID:23508801

Sachs, Michael C.; Zhou, Xiao-Hua Andrew

2013-01-01

433

Treatment of partial distal biceps tendon tears.  

PubMed

Partial rupture of the distal biceps tendon exhibits features similar to that of complete disruption, including acute antecubital pain, weakness of elbow flexion, and forearm supination, and differs only in the fact that the biceps tendon is still palpable in the partial rupture. There are 2 etiologies, first acute traumatic (such as a sudden eccentric contracture) and second, chronic degenerative tendon disease. For accurate diagnosis, a high index of suspicion must be employed. Initial investigations should include plain x-ray and a magnetic resonance scan. Partial tears <50% may be treated with nonoperative management or with surgical debridement of the surrounding synovitis. Tears >50% should be treated with division of the remaining tendon and surgical repair of the entire tendon as a single unit. Surgical endoscopy provides the ability to further quantify the extent of a distal biceps tear and to treat with debridement. This technique, however, should only be used in experienced hands. PMID:18703975

Bain, Gregory I; Johnson, Luke J; Turner, Perry C

2008-09-01

434

Virtual environment application with partial gravity simulation  

NASA Technical Reports Server (NTRS)

To support manned missions to the surface of Mars and missions requiring manipulation of payloads and locomotion in space, a training facility is required to simulate the conditions of both partial and microgravity. A partial gravity simulator (Pogo) which uses pneumatic suspension is being studied for use in virtual reality training. Pogo maintains a constant partial gravity simulation with a variation of simulated body force between 2.2 and 10 percent, depending on the type of locomotion inputs. this paper is based on the concept and application of a virtual environment system with Pogo including a head-mounted display and glove. The reality engine consists of a high end SGI workstation and PC's which drive Pogo's sensors and data acquisition hardware used for tracking and control. The tracking system is a hybrid of magnetic and optical trackers integrated for this application.

Ray, David M.; Vanchau, Michael N.

1994-01-01

435

Does partial melting explain geophysical anomalies?  

NASA Astrophysics Data System (ADS)

The existence of partial melt is frequently invoked to explain geophysical anomalies such as low seismic wave velocity and high electrical conductivity. I review various experimental and theoretical studies to evaluate the plausibility of this explanation. In order for a partial melt model to work, not only the presence of melt, but also the presence of appropriate amount of melt needs to be explained. Using the mineral physics observations on the influence of melt on physical properties and the physics and chemistry of melt generation and transport, I conclude that partial melt model for the asthenosphere with homogeneous melt distribution does not work. One needs to invoke inhomogeneous distribution of melt if one wishes to explain observed geophysical anomalies by partial melting. However, most of models with inhomogeneous melt distribution are either inconsistent with some geophysical observations or the assumed structures are geodynamically unstable and/or implausible. Therefore partial melt models for the geophysical anomalies of the asthenosphere are unlikely to be valid, and some solid-state mechanisms must be invoked. The situation is different in the deep upper mantle where melt could completely wet grain-boundaries and continuous production of melt is likely by “dehydration melting” at around 410-km. In the ultralow velocity zone in the D? layer, where continuous production of melt is unlikely, easy separation of melt from solid precludes the partial melt model for low velocities and high electrical conductivity unless the melt density is extremely close to the density of co-existing solid minerals or if there is a strong convective current to support the topography of the ULVZ region. Compositional variation such as Fe-enrichment is an alternative cause for the anomalies in the D? layer.

Karato, Shun-ichiro

2014-03-01

436

Process for treating partially desulfurized coke  

SciTech Connect

The invention concerns a process for improving the strength properties of partially desulfurized coke, especially petroleum coke, and in such a way that it is then suitable as raw material for electrodes, in particular anodes for the fused salt electrolytic production of aluminum by the hall heroult process. The process according to the invention comprises an aftertreatment of the partially desulfurized coke at an elevated temperature for a duration of at least 30 minutes, as a result of which the strength of the coke increases.

Brandenberger, K.; Feichtinger, A.; Fischer, W.

1982-06-15

437

Partial shape memory effect of polymers  

NASA Astrophysics Data System (ADS)

A blend of PLA (80%) and PBS (20%) has been prepared first by extrusion, then by injection molding. Tensile, stress-relaxation and recovery tests have been performed on the samples at 70°C and 75°C. The results indicated that the blend can regain only 24% of its initial shape. This partial shape memory effect has been improved by successive cycles of shape memory tests. After a fourth cycle, the blend is able to regain 82% of its shape. These original results indicated that a polymer without (or with partial) shape memory effect may be transformed to a shape memory polymer without any chemical modification.

Tcharkhtchi, A.; Elhirisia, S. Abdallah; Ebrahimi, K. M.; Fitoussi, J.; Shirinbayan, M.; Farzaneh, S.

2014-05-01

438

[Simple partial frontal nonconvulsive status epilepticus].  

PubMed

Non convulsive status epilepticus (NCSE) of frontal origin is a rare cause of mental confusion. The present case of possible frontal-onset NCSE proved to have a neuropsychological examination that was suggestive either of a disruption of attentional function or a left prefrontal dysfunction, exhibiting disturbances of immediate memory and logical programmation, perseverations and affective disinhibition. Vigilance was not impaired. This case was therefore, on a nosographic point of view, more consistent with a simple partial status epilepticus with cognitive and affective symptomatology rather than with a complex partial status epilepticus of extra-temporal origin. PMID:9684010

Thomas, P; Mottin, Y

1997-07-01

439

Solute partial molal volumes in supercritical fluids  

SciTech Connect

A novel technique is described for the measurement of the partial molal volume at infinite dilution of solutes in supercritical fluids. Results are reported for five systems from 2/sup 0/C above the solvent critical temperature up to 15/sup 0/C above, at pressures from just above the critical pressure to 350 bars. The solute partial molal volumes are small and positive at high pressures, but very large and negative in the highly compressible near-critical region. The results are interpreted in terms of solvent structure and intermolecular forces.

Eckert, C.A.; Ziger, D.H.; Johnston, K.P.; Kim, S.

1986-06-05

440

Methods for producing partially digested restriction DNA fragments and for producing a partially modified PCR product  

DOEpatents

The present invention is an improved method of making a partially modified PCR product from a DNA fragment with a polymerase chain reaction (PCR). In a standard PCR process, the DNA fragment is combined with starting deoxynucleoside triphosphates, a primer, a buffer and a DNA polymerase in a PCR mixture. The PCR mixture is then reacted in the PCR producing copies of the DNA fragment. The improvement of the present invention is adding an amount of a modifier at any step prior to completion of the PCR process thereby randomly and partially modifying the copies of the DNA fragment as a partially modified PCR product. The partially modified PCR product may then be digested with an enzyme that cuts the partially modified PCR product at unmodified sites thereby producing an array of DNA restriction fragments.

Wong, Kwong-Kwok (Richland, WA)

2000-01-01

441

Methods for producing partially digested restriction DNA fragments and for producing a partially modified PCR product  

SciTech Connect

The present invention is an improved method of making a partially modified PCR product from a DNA fragment with a polymerase chain reaction (PCR). In a standard PCR process, the DNA fragment is combined with starting deoxynucleoside triphosphates, a primer, a buffer and a DNA polymerase in a PCR mixture. The PCR mixture is then reacted in the PCR producing copies of the DNA fragment. The improvement of the present invention is adding an amount of a modifier at any step prior to completion of the PCR process thereby randomly and partially modifying the copies of the DNA fragment as a partially modified PCR product. The partially modified PCR product may then be digested with an enzyme that cuts the partially modified PCR product at unmodified sites thereby producing an array of DNA restriction fragments.

Wong, K.K.

2000-04-04

442

Partially Decentralized Control Architectures for Satellite Formations  

NASA Technical Reports Server (NTRS)

In a partially decentralized control architecture, more than one but less than all nodes have supervisory capability. This paper describes an approach to choosing the number of supervisors in such au architecture, based on a reliability vs. cost trade. It also considers the implications of these results for the design of navigation systems for satellite formations that could be controlled with a partially decentralized architecture. Using an assumed cost model, analytic and simulation-based results indicate that it may be cheaper to achieve a given overall system reliability with a partially decentralized architecture containing only a few supervisors, than with either fully decentralized or purely centralized architectures. Nominally, the subset of supervisors may act as centralized estimation and control nodes for corresponding subsets of the remaining subordinate nodes, and act as decentralized estimation and control peers with respect to each other. However, in the context of partially decentralized satellite formation control, the absolute positions and velocities of each spacecraft are unique, so that correlations which make estimates using only local information suboptimal only occur through common biases and process noise. Covariance and monte-carlo analysis of a simplified system show that this lack of correlation may allow simplification of the local estimators while preserving the global optimality of the maneuvers commanded by the supervisors.

Carpenter, J. Russell; Bauer, Frank H.

2002-01-01

443

Transfer Matrix for Partially Quenched QCD  

E-print Network

We construct the transfer matrix for the ghost sector of partially quenched QCD. This transfer matrix is not hermitian, but we show that it is still bounded. We thus expect that all euclidean correlation functions will decay exponentially with distance (up to possible powers), and demonstrate that this is indeed the case for free ghost quarks.

Claude Bernard; Maarten Golterman

2010-10-31

444

Pseudo skin factor due to partial penetration  

Microsoft Academic Search

In this study the authors examine the pseudo skin factor due to partial penetration in a two-layer reservoir when only one layer is open to flow. They show that the pseudo skin factor can be correlated as a unique function of three reservoir parameters and in some cases can be accurately correlated as a function of two reservoir parameters. They

A. C. Reynolds; J. C. Chen; R. Raghavan