This article provides information regarding the many ways that removable partial dentures (RPDs) may be used to solve restorative problems in the esthetic zone without displaying metal components or conspicuous acrylic resin flanges. The esthetic zone is defined and described, as are methods for recording it. Six dental categories are presented that assist the dentist in choosing a variety of RPD design concepts that may be used to avoid metal display while still satisfying basic principles of RPDs. New materials that may be utilized for optimal esthetics are presented and techniques for contouring acrylic resin bases and tinting denture bases are described. PMID:15544224
This article describes a simple and efficient technique for increasing the occlusal vertical dimension of removable denture wearers. Functionally generated path technique is carried out by using gothic arch tracing, and the existing mandibular overdenture is modified for interim use. PMID:22409139
Sulun, Tonguc; Geckili, Onur
The success of a removable partial denture, the comfort for the patient, stability and especially the psychological acceptance depend on a series of essential technicals factors. Probably the more delicate stage of the prosthetic technology is the transfer of informations from the mouth of the patient to the prothesist through the impression. In removable partial denture, impression have to take account into the balance between uncompressible hard tissue and soft structures with variable compressibilities. The diversity of clinical cases is responsible for a large diversity of techniques. The aim of this article is to describe the more common technics used in every day practice. PMID:16193853
Prapotnich, R; Domken, O
... 11.14 Read More Find a Cosmetic Dentist Teeth Whitening Accredited and General Member Dental Patients ? Cosmetic Procedures ? Dentures Dentures Partial Dentures For many years, partial dentures have been used to replace groups of teeth or a few teeth scattered across the lower ...
No single occlusal morphology, scheme, or material will successfully treat all patients. Many patients have been treated, both successfully and unsuccessfully, using widely varying theories of occlusion, choices of posterior tooth form, and restorative materials. Therefore, experience has demonstrated that there is no one righ r way to restore the occlusion of all patients. Partially edentulous patients have many and varied needs. Clinicians must understand the healthy physiologic gnathostomatic system and properly diagnose what is or may become pathologic. Henderson  stated that the occlusion of the successfully treated patient allows the masticating mechanism to carry out its physiologic functions while the temporomandibular joints, the neuromuscular mechanism, the teeth and their supporting structures remain in a good state of health. Skills in diagnosis and treatment planning are of utmost importance in treating these patients, for whom the clinician's goals are not only an esthetic and functional restoration but also a lasting harmonious state. Perhaps this was best state by DeVan  more than 60 years ago in his often-quoted objective. "The patient's fundamental need is the continued meticulous restoration of what is missing, since what is lost is in a sense irretrievably lost." Because it is clear that there is no one method, no one occlusal scheme, or one material that guarantees success for all patients, recommendations for consideration when establishing or reestablishing occlusal schemes have been presented. These recommendations must be used in conjunction with other diagnostic and technical skills. PMID:15261799
Ivanhoe, John R; Plummer, Kevin D
Conventional fixed partial dentures, implant supported Fixed Partial Dentures (FDPs) and removable partial dentures are the most common treatment modalities for the aesthetic and functional rehabilitation of partially edentulous patients. Although implants and FDP have certain advantages over removable partial dentures, in some cases, removable partial dentures may be the only choice which is available. Removable cast partial dentures are used as definitive removable prostheses when indicated, but location of clasps may affect aesthetics. So, when patient is concerned about aesthetics, flexible partial dentures which is aesthetically superior to flipper and cast partial dentures, may be considered. But for the success of flexible removable partial denture, proper diagnosis, treatment planning and insertion technique of this prosthesis is very important, which have been thoroughly described in this article. PMID:24298532
Singh, Kunwarjeet; Aeran, Himanshu; Kumar, Narender; Gupta, Nidhi
Conventional fixed partial dentures, implant supported Fixed Partial Dentures (FDPs) and removable partial dentures are the most common treatment modalities for the aesthetic and functional rehabilitation of partially edentulous patients. Although implants and FDP have certain advantages over removable partial dentures, in some cases, removable partial dentures may be the only choice which is available. Removable cast partial dentures are used as definitive removable prostheses when indicated, but location of clasps may affect aesthetics. So, when patient is concerned about aesthetics, flexible partial dentures which is aesthetically superior to flipper and cast partial dentures, may be considered. But for the success of flexible removable partial denture, proper diagnosis, treatment planning and insertion technique of this prosthesis is very important, which have been thoroughly described in this article.
Singh, Kunwarjeet; Aeran, Himanshu; Kumar, Narender; Gupta, Nidhi
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
Partial or complete edentulism impairs mastication. However, it is unclear how the chewing cycle is affected by prosthetics. We evaluated the chewing movements of patients fitted with complete (CD) or removable partial denture (RPD). A total of 29 subjects were kinesiographically evaluated during chewing of peanuts and Optocal portions in a random sequence. The subjects were divided into two groups according to prosthesis type. Group RPD was composed of 14 partially edentulous patients using a lower distal extension RPD (mean age 61 ± 8 years), and group CD contained 15 completely edentulous patients using CD (mean age 65·9 ± 7·9 years) in both jaws. Opening, closing, occlusal and masticatory cycle times, movement angle (opening and closing), maximum velocity (opening and closing), total area and chewing cycle amplitudes were evaluated. The results were subjected to anova and Tukey's HSD test at a significance level of 5%. The RPD group exhibited shorter opening and closing phases and masticatory cycle time (P < 0·05). Maximum velocities were also higher in the RPD group, irrespective of the test material (P < 0·05). The area and amplitude of the chewing envelope was smaller in the CD group (P < 0·0001). The test material did not influence chewing cycles in any of the parameters evaluated (P > 0·05). RPD wearers use a faster chewing sequence with greater vertical and lateral jaw excursions compared with CD wearers. PMID:24372333
Gonçalves, T M S V; Vilanova, L S R; Gonçalves, L M; Rodrigues Garcia, R C M
Implants have been designed to provide edentulous patients with fixed prostheses or overdentures. Recently, implant-supported fixed partial prostheses and single crowns have become successful treatment alternatives to removable and fixed partial dentures. However, few researchers have examined "removable partial dentures on implants and natural teeth". In this article, we report two patients fitted with "removable partial dentures on implants and natural teeth". The patients were satisfied with their dentures in terms of function and aesthetics. Regular follow-up visits revealed that the periodontal and peri-implant conditions were stable. There was no evidence of excessive intrusion or mobility of the teeth, nor were any visible changes in the bone levels of the natural teeth or implants noted on radiographs. Since the average duration of observation was about 38 months, further follow-up examinations are necessary to determine whether these dentures remain stable long-term. PMID:17760280
Chang, Li-Ching; Wang, Jen-Chyan; Tasi, Chi-Cheng
Most of the removable partial denture castings examined showed radiographic evidence of internal porosity. In general the porosity ocurred in characteristic regions associated with abrupt changes in cross-sectional thickness. These were located either within the partial denture framework or at the casting-sprue junctions. The porosity is due to metal shrinkage caused by a premature solidification at some point, which in turn interferes with a controlled unidirectional soldification of the casting. PMID:273090
Lewis, A J
The impact of oral disorders and interventions on individuals' perceived oral health and oral-health-related quality of life (OHRQoL) is being increasingly recognized as an important health component. This study examined the association between denture quality and OHRQoL in individuals wearing removable partial dentures (RPDs). The study participants were 245 consecutive patients (mean age: 63.3 ± 8.7 yrs) at a university-based
M. Inukai; K. Baba; M. T. John; Y. Igarashi
Our aim is to report an application of a prefabricated light-polymerizing plastic pattern to construction of removable partial denture framework without the use of a refractory cast. A plastic pattern for the lingual bar was adapted on the master cast of a mandibular Kennedy class I partially edentulous patient. The pattern was polymerized in a light chamber. Cobalt-chromium wires were employed to minimize the potential distortion of the plastic framework. The framework was carefully removed from the master cast and invested with phosphate-bonded investment for the subsequent casting procedures. A retentive clasp was constructed using 19-gauge wrought wire and was welded to the framework by means of laser welding machine. An excellent fit of the framework in the patient's mouth was observed in the try-in and the insertion of the denture. The result suggests that this method minimizes laboratory cost and time for partial denture construction. PMID:22346178
Takaichi, Atsushi; Wakabayashi, Noriyuki; Igarashi, Yoshimasa
The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt-chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998-2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76.3%) actually attended. For a total of 292 RPDs fitted for these 254 patients, 218 (74.7%) were still being worn at the time of the check-up. Seventy-four dentures were considered to be 'failures', either because they were replaced by another RPD or by a complete denture, or because they had actually never been worn. The statistical analysis (Mantel-Haenszel and Kaplan-Meier) shows that the number of failures is significantly higher at the lower jaw compared with the upper jaw. Most of the failures are attributable to RPDs with free-end saddles and, in particular, to class I mandibular dentures. The patients are wearing their denture(s) mostly continuously (63.6%) and award a high degree of satisfaction to their denture. In general, the results recorded may be considered as very satisfactory, all the more so as we have no regular recall procedures established at our school and as check-up asked for spontaneously by the patients in the course of the period of observation are most of the time occasional or non-existent. PMID:12752923
Vanzeveren, C; D'Hoore, W; Bercy, P; Leloup, G
Commonly observed complications associated with a conventional fixed partial denture (FPD) include loss of retention and tooth fracture. This report describes the occurrence of an unusual FPD abutment fracture and subsequent treatment. The distal abutment of an FPD developed severe periodontal disease with mobility. The anterior abutment fractured in the middle of the clinical crown and experienced cement failure. PMID:15623993
Verrett, Ronald G; Kaiser, David A
This article describes a technique to enhance resistance form in the construction of anterior resin-bonded fixed partial dentures. The technique is simple and conserves tooth structure. It uses a cingulum pin when an opposing axial groove cannot be adequately incorporated into the preparation. PMID:2066879
Lankford, R J; Christensen, L C
The casting removable partial denture (RPD) is one of most commonly prosthesis methods in present. Vitallium is one kind of dental alloy with cobalt, chromium and molybdenum etc. It has three ranks respectively: Vitallium, Vitallium 2000 and Vitallium 2000 plus. Although the traditional casting RPD are commonly used, but it has been limited in the physical capabilities of traditional dental alloy. It would not been done to flexible design on denture especially on denture base. The elasticity of casting clasp is not good, the volume is thick. Because of the Vickers hardness and elongation of Vitallium 2000 and Vitallium 2000 plus are better than traditional dental alloys, so the RPD with Vitallium 2000 has good bending control, deformation rebound and fracture resistance. The benefit of Vitallium 2000 or Vitallium 2000 plus is the RPD with splitting can be designed for some free end clinical cases, to solve some clinical problems. PMID:19472868
The joining procedure for uniting metal structures is very important in the dental clinic, and various kinds of metal joining methods have been performed for clinical application. The conventional torch soldering method using a blow torch has been generally adopted. However, it has several clinical problems, especially in the construction of removable partial dentures. The base metal wires made of a chromium-cobalt alloy are subject to changes in their mechanical properties caused by heating, when wrought wire clasps are joined to rests or frameworks. In addition to the flexibility of wrought wire clasps, damage to acrylic resin denture bases and acrylic resin teeth occurs in the repair of removable partial dentures. In this paper, the electric resistance welding and soldering methods were applied to attach wrought wire components to a removable partial denture framework to resolve the problems of the torch soldering method. As a result, it is suggested that these electric resistance welding and soldering methods have the following advantages, as compared with the conventional torch soldering method. 1. When using this electric resistance welding method, it is possible to fix metals temporarily to each other more securely and strongly than the conventional temporary fixation methods using sticky wax or acrylic resin. 2. The electric resistance soldering method does not require any heat insulation or a partition as the torch soldering method does, because the soldered area is only heated partially. 3. In the case of soldering electrically wrought wire clasps to metal structures such as rests and connectors, there is no fear of of overheating a wide area of wires.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1983722
Nakamura, S; Nokubi, T; Ono, T; Ikebe, K; Okuno, Y; Taga, Y
The inaccuracies of the casting and fitting processes associated with semiprecision intracoronal attachment systems may compromise the fit of the completed prosthesis. The objective of using metal prefabricated intracoronal semiprecision attachments is to improve the adaptation between the matching attachment surfaces used in the fabrication of removable partial dentures. In milled dovetail or waxed dowel rests, the attachment of one side is completed and the other is cast to match. The prefabricated attachment system presented uses a matching component cast directly against the precast metal rest-mandrel. This reduces the inaccuracies resulting from waxing, investing, and casting. PMID:2700629
Zinner, I D; Miller, R D; Parker, H M; Panno, F V
Statement of problem. Burs with guide pins may be used to limit the depth of tooth preparation for fixed partial dentures. The effects of guide pins on tooth structure apical to the finish line after tooth preparation for fixed partial dentures has not been recorded.Purpose. This in vitro study recorded loss of tooth structure within 1.0 mm apical to the
Merrie H. Ramp; Michael S. McCracken; Raquel B. Mazer
This article describes the use of an all ceramic resin-bonded fixed partial denture as a conservative solution for the replacement of an incisor. It is a minimally invasive technique that does not discolor the abutment teeth.
Kara, Haluk Baris; Aykent, Filiz
Fixed partial dentures can be fabricated by means of different materials and with different manufacturing processes. In order to establish possible differences among them, their behaviour, as fatigue life or cement shear bond strength, have to be evaluated. This article presents a modular, economic and robust device to evaluate fixed partial dentures and dental crowns. A base to support the fixed partial dentures and a device to simulate masticatory loads have been developed. The device has got a simple design. It is based on a pneumatic piston, with a pressure regulator to control masticatory loads. On a first stage, only vertical forces have been taking into account. However, the device will allow simulating tangential masticatory loads on the other axis, studying the behaviour of the fixed partial dentures submerged in a solution similar to saliva, changing masticatory load application, etc. with little modifications.
Gutierrez, S. C.; Meseguer, M. D.; Estal, R.; Folguera, F.; Vidal, V.
SUMMARY Objective The aim of this study is a systematic review of the literature on the strength and long-term behavior of zirconia FPDs. Methods The literature search was performed using as the primary source the Medline database. Were also imposed a set of inclusion and exclusion criteria in order to narrow the search to differentiate the two distinct parts in which it was structured the review. In addition, MeSH terms were applied to further refine the choice of articles more relevant to the review. In the part of the review concerning the long-term behavior of zirconia fixed partial dentures were considered useful only those studies with a minimum follow-up of one year. Results The search provided a total of 813 articles, but only 25 were considered for the review because they were the only ones who satisfied search criteria. In particular, 13 items relate to the mechanical strength of zirconia prostheses and 12 regarding the long term behavior of zirconia FPDs. The resistance values also exceed the 2000 N while the survival rate reaches to almost 94%. Conclusions Based on this review, Zirconia FPDs can be considered reliable products in both the anterior and posterior fields with survival rates comparable to traditional metal-ceramic prostheses.
GARGARI, M.; GLORIA, F.; CAPPELLO, A.; OTTRIA, L.
Twelve patients were followed for 15 years after treatment with a 12-unit cantilever fixed partial denture on the mandibular canines opposite to a complete maxillary denture. Four constructions failed and had to be removed but four were still in function after 15 years. Four patients died during the observation period still wearing their constructions. Endodontic complications, pulpal necrosis and loss of retention of posts were the most frequent, while caries and periodontal lesions were rare. The maintenance costs over the years were fairly low even compared to maintenance costs for patients treated with implants. Extensive mandibular cantilever fixed partial dentures may be used in the rehabilitation of patients with a very reduced dentition and a history of difficulties adapting to removable dentures. PMID:8667121
Carlson, B R; Yontchev, E
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.
Borba, Marcia; Cesar, Paulo F.; Griggs, Jason A.; Della Bona, Alvaro
The aim of this study was to evaluate the effectiveness of an oral rehabilitation by removable partial denture (RPD). Between 1983 and 1994, 629 patients were provided with an RPD at the Dental School of the Université catholique de Louvain. All the RPDs were constructed with a cobalt-chromium framework. All the treatments were provided by dental students under the supervision of clinical instructors. At recall time (1998-2000), 269 patients could not be reached neither by telephone nor by mail and 27 had died. Consequently, 333 patients were called for clinical examination and 254 of these (76.3%) actually attended. For a total of 292 RPDs checked 1893 persistent teeth were listed, with 804 serving as abutments; more than half (57.6%) of these were crowned, for which 51 debondings were recorded. For the period of observation we listed 79 abutments lost (37 at the upper jaw and 42 at the lower jaw), i.e. 9.8% of the total number of abutments. No relation could be established between the type of the abutments (natural or crowned teeth) and the losses observed (Test of Mantel-Haenszel: P=0.9496). In the upper jaw, the percentage of abutments lost was significantly higher in the presence of free-end edentulous areas as compared with bounded edentulous areas (Test of Mantel-Haenszel: P=0.0002); this difference does not appear for the lower jaws (P=0.9558). If we deduct the 25 abutments related with the 11 non-worn RPDs and the 79 abutments lost, no change becomes apparent for 92.2% of the maxillary abutments and for 85.8% of the mandibular abutments. For the 1089 other teeth, we observed the loss of 40 teeth and the appearance of caries or new fillings for 95 teeth. The fractures of cast clasps represent 3.4%. PMID:12752924
Vanzeveren, C; D'Hoore, W; Bercy, P; Leloup, G
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.
Rosentritt, Martin; Behr, Michael; Kolbeck, Carola; Handel, Gerhard
The aim of this in vitro study was to determine the thermal mechanical properties of veneering composites after polymerization with the appropriate polymerization device. Fracture tests were performed to investigate the effect on fixed partial dentures (FPDs). Dynamic mechanical thermal analysis was used to determine the temperature-dependent mechanical properties. To approximate the clinical situation, the fracture resistance of three-unit metal-based FPDs with different composite veneering was investigated after a simulated 5-year oral wearing period. The restorations were made of a high gold alloy and veneered with three different composites. To determine the influence of fabrication, one composite was used in a light-polymerizing and a heat/pressure-curing version and, in addition, a newly developed heat protection paste was used. After a 5-year simulation period, the fracture resistance was determined. The storage modulus varied between 14268 N mm(-2) (Belleglass) and 6616 N mm(-2) (Sinfony). Adoro showed no significant differences between light curing (9155 N mm(-2)) and heat curing (8184 N mm(-2)) variations. The Adoro-veneering with the heat protection paste showed the highest median fracture strength (1700 N), followed by Adoro LC (1555 N), Belleglass (1051 N), Adoro HP (1150 N) and Sinfony (909 N). The most common failure type occurring in all FPDs was a cracking of the composite, exposing the metal framework. All FPDs showed stress cracking of the composite. The heat protection paste seemed to reduce the crack formation after fabrication and increased the fracture resistance of the composite veneering. Stress cracking after thermal cycling and mechanical loading affected all composites, but all veneered three-unit alloy FPDs showed a fracture resistance sufficient for posterior application. PMID:16011641
Rosentritt, M; Behr, M; Brückner, H; Handel, G
The aim of this study was to investigate the clinical outcome of removable partial dentures (RPDs) designed to minimize denture mobility during function. Using archived files of the undergraduate program between 2003 and 2005 at Tokyo Medical and Dental University, a list of 169 patients treated with 184 RPDs was created. The RPDs had either an acrylic resin-base or a cobalt-chrome framework-base. Two examiners telephoned all the listed patients and interviewed 118 patients (70%) regarding the use of their RPDs. Of 118 patients, 42 (36%) had stopped using, mainly due to problems with abutment teeth in resin-based dentures, and replacement in cobalt-chrome-based dentures. There was no significant difference in mean age, gender distribution, mean number of remaining/abutment teeth, distribution of denture arch, and Kennedy classification between denture use and nonuse groups (p>0.05). The nonuse group showed a significantly higher percentage of resin-base compared to the use group (p = 0.006). Logistic regression analysis indicated that resin-base was a significant risk factor for nonuse (p = 0.008). The present findings suggest that abutment teeth should be selected carefully, especially in this type of resin-based RPDs, and that the denture base material may be a critical factor which determines denture use. PMID:23896787
Yoshida, Eiko; Fueki, Kenji; Igarashi, Yoshimasa
The joining procedure for uniting metal structures is very important in the construction of removable partial dentures. However, it has several restricted problems in joining wrought wire clasps to rests or major connectors. For example, the base metal wires made of chromium-cobalt alloy are subject to changes in their mechanical properties caused by heating, and damage to acrylic resin materials (denture base and artificial teeth) occurs in the repair of removable partial dentures by using the torch soldering method. In this paper, in order to resolve these problems, an electric resistance welding machine was applied to attach wrought wire components to a removable partial denture framework. This welding machine was used to attach metal structures temporarily to each other, and to solder the welded joint with hard solder. Consequently, some problems of the conventional torch soldering method were improved by using the electric resistance welding and soldering methods. It was suggested that the clinical application of the electric welding and soldering methods was very useful in the construction of removable partial dentures. PMID:1983361
Nokubi, T; Nakamura, S; Ono, T; Ikebe, K; Kita, S; Okuno, Y; Taga, Y
Aim of this study was to determine the prevalence of removable denture (complete and partial) deliveries through Croatian Public Health Service (covered by insurance) in different districts of Croatia and to compare the two periods: 1996 to 2001 and 2002. Number of dentures delivered was obtained from Croatian Institute for Health Insurance for the district of Zagreb, Rijeka, Split and Karlovac. Information of the population living in the same districts was obtained from the National Institute for Statistics. The percentage of fully edentulous inhabitants varied from more than 13% to more than 20%, dependent on the district, while the percentage of partial edentulism reconstructed with removable partial dentures varied from more than 13% to more than 30%. The highest percentage (average for living population) of complete and removable partial dentures was delivered in Zagreb in the both observed periods. In all districts, the number of complete denture wearers increased in 2002, except in Split. The percentage of removable partial denture deliveries increased significantly in all examined districts. Partial and complete denture deliveries increased in higher percentage in population younger than 70 years than in older population. The percentage of metal framework removable partial dentures increased significantly in all districts. The prevalence of removable denture deliveries increased, especially in patients younger than 70 years. This was attributed not only to the consequences of the 1991-1995 war, the migrations from rural to urban areas, decrease of economic status, but also to the new rules of the Croatian Insurance System. PMID:16117310
Poljak-Guberina, Renata; Celebi?, Asja; Catovi?, Adnan; Zivkovi?, Ognjen
BACKGROUND Though implant dentistry is very successful and predictable in treatment of patients with destroyed dentition, there are some cases with limitations to implant therapy. In these cases, alternative treatment modality should be considered. CASE DESCRIPTION A patient with destroyed dentition was rehabilitated with a lateral rotational path removable partial denture. According to the diagnosis, we determined to raise vertical dimension for esthetic and functional restoration. The final restoration was performed after four months of provisional period. CLINICAL IMPLICATION The edentulous patients with compromised esthetics and functions can be successfully treated with a rotational path removable partial denture through adequate treatment planning and precise laboratory procedure.
Kim, Moon-Hyoung; Heo, Seong-Joo; Kim, Seong-Kyun
The provision of patients with removable partial dentures on all-ceramic primary crowns with electroplated gold secondary parts is described as an alternative worthy of consideration in dental journals, lectures and in further training courses. The mode of operation is based on a precise, frictionless, passive fit between female and male components. To guarantee this even over large spans, intraoral joining of the individual components is necessary. However, this requires a different sequence of the treatment steps. The different procedures (conventional, procedure by Weigl, modified concept) are described in the following article. Clinical considerations, design principles, and special characteristics involved in producing the partial denture are explained. PMID:19119547
Bär, C; Reich, S
For patients with shortened dental arches, many treatment options are available. The existing situation can be maintained by stabilizing the present dentition and improving the occlusion without extending the arch. Alternatively, the shortened dental arch can be extended by either a free-end saddle removable partial denture, cantilevered fixed bridge, or by an implant-supported prosthesis. The free-end saddle removable partial denture can be considered a simple, non-invasive, and relatively cheap treatment option for the shortened dental arch. It was believed that such prosthodontic rehabilitation would be beneficial for the patients in terms of improving oral functions. However, the existing literature indicates that the prognosis of free-end saddle removable partial denture is not predictable, it is problematic, and its contribution to oral functions in patients with shortened dental arches is considered to be dubious. This paper reviews and summarizes the current literature about the outcome of extending the shortened dental arch by a free-end saddle removable partial denture. It also outlines factors that may affect the prognosis of this prosthetic treatment.
Nassani, Mohammad Zakaria; Tarakji, Bassel; Baroudi, Kusai; Sakka, Salah
Techniques for treating a fully or partially edentulous patient with microstomia have been developed to overcome the challenge of accessing the oral cavity. Management of the problems associated with providing implant-supported fixed partial dentures for patients with microstomia has not been well reported. This article describes a solution for the transfer problem that occurs when making an impression of an implant-supported fixed partial dentures for patients with microstomia. PMID:22103246
Uludag, Bulent; Polat, Serdar; Sahin, Volkan; Tokar, Emre; Ertug, Omer
The aesthetic replacement of anterior teeth in cases of immediate partial denture is always a challenging work for prosthodontists. There is always problem of matching size, colour, shade and shape of the replaced tooth with those of the natural teeth. It was most difficult to satisfy the patients who have high aesthetic demands. Here is a report of a case where patient's own natural tooth was used for replacement in an immediate partial denture. An immediate denture is defined as "any removable dental prosthesis which is fabricated for placement immediately, following the removal of a natural tooth/teeth" . Patients with missing anterior teeth lack an impressive appearance aesthetically and as well as psychologically. Tooth loss leads to a certain degree of loss of function. This loss of function might lead to an impairment of oral health which is related to quality of life. An immediate denture can replace 1-16 teeth in either the maxillary or the mandibular arch, or in both arches. The need for the immediate replacement of a missing tooth is more in case of an anterior tooth, where aesthetics is of prime concern. The replacement of an anterior tooth is most technique sensitive, as it includes the patient's expectations, which include, matching with proper shade, shape and size as those of his/her natural teeth. So, here is a case presentation where modern day patient expectations were taken into consideration. PMID:24086926
Satapathy, Sukanta Kumar; Pillai, Ajay; Jyothi, Ramya; Annapurna, P Durga
The aesthetic replacement of anterior teeth in cases of immediate partial denture is always a challenging work for prosthodontists. There is always problem of matching size, colour, shade and shape of the replaced tooth with those of the natural teeth. It was most difficult to satisfy the patients who have high aesthetic demands. Here is a report of a case where patient’s own natural tooth was used for replacement in an immediate partial denture. An immediate denture is defined as “any removable dental prosthesis which is fabricated for placement immediately, following the removal of a natural tooth/teeth” . Patients with missing anterior teeth lack an impressive appearance aesthetically and as well as psychologically. Tooth loss leads to a certain degree of loss of function. This loss of function might lead to an impairment of oral health which is related to quality of life. An immediate denture can replace 1-16 teeth in either the maxillary or the mandibular arch, or in both arches. The need for the immediate replacement of a missing tooth is more in case of an anterior tooth, where aesthetics is of prime concern. The replacement of an anterior tooth is most technique sensitive, as it includes the patient’s expectations, which include, matching with proper shade, shape and size as those of his/her natural teeth. So, here is a case presentation where modern day patient expectations were taken into consideration.
Satapathy, Sukanta Kumar; Pillai, Ajay; Jyothi, Ramya; Annapurna, P. Durga
Resin-bonded fixed partial dentures have been in use for over 30 years, since the concept was first introduced in the 1970s. Initial efforts in this field suffered frequent early debond, but advances in metal alloys, treatment of the fitting surface and bonding techniques have made the resin-bonded fixed partial denture a predicable treatment modality. Design principles have also evolved. Originally these restorations were retained purely through adhesion, but now minimal preparation of the abutment teeth may be undertaken to optimise mechanical resistance and retention forms. This facilitates delivery of a more predicable medium- to long-term restoration. Alternative materials such as ceramic, zirconia and fibre-reinforced composite resin have emerged for retainers. While these alternatives show promise, they are not without their disadvantages and do not yet have long-term data regarding their use for this application. PMID:23420968
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
The fabrication of a new crown to replace an existing abutment tooth for a removable partial denture is one of the most labor-intensive chairside and laboratory procedures. The process can become more complicated when the patient requests a tooth-colored esthetic restoration. Numerous techniques are described in the literature, some for all-metallic restorations and others for metal-ceramic restorations. This article describes a simplified technique that makes use of a polymer ceramic material. PMID:12011850
Helvey, Gregg A
The effects of four sequential modifications to improve occlusion, vertical dimension, retention, and stability of poorly fitting dentures, and of placing new dentures, on the EMG activity were investigated in 21 denture wearers with a mean age of 67.7 years. Electromyographic recordings of right and left masseter muscles were made while the subjects performed masticatory and swallowing threshold tests and
Neal R Garrett; Paul Perez; Charles Elbert; Krishan K Kapur
Interim partial dentures are used often to temporarily restore a patient's dentition to create a satisfactory phonetic, esthetic, and occlusal relationship. This article presents a case involving a patient with an aging self-maintained provisional. A modified technique for interim prosthesis fabrication was utilized that involves decoronation of the teeth prior to extraction, so that the anatomical soft tissues can be visualized. This technique is a cost-effective, expeditious approach to restore function in a single appointment for patients with tooth loss who do not wish to be partially edentulous. PMID:24983165
Rammal, M; Alfonso, C
The aim of this study was to compare the quality of fixed partial dentures (FPDs) made in a Chinese dental laboratory with corresponding FPDs made in Swedish dental laboratories. Twenty-one patients were fitted with FPDs between March 2007 and December 2008. Single crowns and prostheses of up to seven units were made. All dentures, gold and CoCr alloys covered with ceramic, were produced in duplicate: one by a dental technician in China and the other by a dental technician in Sweden. The dentures were blind-tested with regard to marginal integrity, anatomic form and color, approximal and occlusal contacts, and time taken for adjustments. The composition of dentures was analyzed, and the material used, framework weight, compliance of the laboratories, and costs (material and labour) were recorded. There was no difference in the quality of marginal integrity, anatomic form, color, approximal and occlusal contacts, or in the time taken for adjustments. The bridge frameworks made in China were thinner and lighter (p<0.01) than those made in Sweden. Three FPDs from China showed elastic deformation when tested clinically and were considered too thin for clinical use. In 11 out of 14 orders from the Chinese laboratory, the gold alloy specified was not delivered and the cobalt-chromium alloy contained small amounts (0.19%) of nickel.The prostheses with gold-alloy frameworks from China cost 47% of those from Sweden (p<0.01) and those with cobalt/chromium frameworks 44% (p<0.01). In conclusion, the quality of the FPDs made in Sweden and China was comparable, with the exception of the dimension of the Chinese bridges, which in some cases was considered too weak. The gold alloy ordered from the Chinese laboratory was often not the alloy delivered and the CoCr alloy contained small amounts of nickel. FPDs from China cost less than half the price of those from Sweden. PMID:22135942
Ekblom, Karin; Smedberg, Jan-Ivan; Moberg, Lars-Erik
The objective of this study was to determine the flexural properties and the release of chlorhexidine digluconate (CHX) of CHX laced unidirectional E-glass fibre reinforced provisional fixed partial denture polymer. Bar shaped test specimens (3.3 x 10.0 x 65.0 mm) were fabricated from provisional fixed partial denture polymer (mixture of poly[ethylmethacrylate] powder and n-poly[butyl methacrylate] monomer liquid) with E-glass fibre reinforcements. Poly(methyl methacrylate) preimpregnated continuous unidirectional glass fibre reinforcement was laced with CHX. The glass fibre reinforcements were incorporated into the polymer and the polymerised to the form of test specimens. In addition test specimens without CHX in glass fibre reinforcement were made for comparison. Control specimens did not contain glass fibres in the test specimens. Flexural strength and modulus of test specimens (n = 6) was tested with three-point bending test after storing the specimens dry or in water (two weeks). Released CHX was determined with high performance liquid chromatography during 180 days water immersion. In dry conditions, the flexural strength and the modulus of the polymer was 43 MPa and 1.7 GPa, and with glass fibre reinforcement 96 MPa and 3.5 GPa. With the reinforcement laced with CHX, the strength was 92 MPa and the modulus was 3.2 GPa. The water storage of test specimens did not weaken the reinforced polymer. The majority of the CHX released from the glass fibre reinforced polymer during the first days of storage in water. Flexural properties of provisional fixed partial denture polymer were increased using glass fibre reinforcement. The fibre reinforcement that was laced with CHX resulted in similar reinforcing effect. PMID:15747188
Lahdenperä, Milla S; Puska, Mervi A; Alander, Pasi M; Waltimo, Tuomas; Vallittu, Pekka K
This clinical report described the oral rehabilitation of a cleft lip and palate patient with removable partial denture. Although implant-supported fixed treatment was presented as part of the optimum treatment plan to achieve the best result, the patient declined this option due to the significant financial burden. Persons with a congenital or craniofacial defect are unique, and oral problems must be evaluated individually to the most ideal treatment. The changes in appearance, function, and psychological wellbeing have an enormous impact on patients' personal lives and are rewarding for the maxillofacial prosthodontist providing this care.
The change of oral residual alveolar ridge showing in X-ray films before and after wearing unilateral distal extension partial dentures for ten cases was observed by the image processing technique. It was demonstrated that the image processing technique is an available method for evaluating the degree of alveolar ridge resorption both quantatively and qualitatively. By the technique of pantomography of X-ray we can control the coincidence of the corresponding part of the X-ray film taking at different time. So we can use this method to study the regularity of the residual alveolar ridge resorption. PMID:1815857
Liu, W M
The microleakage at the interface between the metal infrastructure and the veneering part of the fixed partial dentures are a common problem of aesthetic dentistry. It is possible to use the method of laser microspectral analysis for investigations of microleakage at the metal-veneering material interfaces in fixed partial prostheses. The laser microspectral analysis device LMA-10 (Carl Zeiss, Jena) was used equipped with a diffraction spectrometer PGS-2 (Carl Zeiss, Jena). Different fixed partial dentures were used to determine the microleakage between the metal infrastructure and the veneering material. The distribution of chemical elements at interface infiltration was investigated, making a series of craters and establishing the spectra of the vapours emitted from the craters. Data was gathered in various tables of chemical elements showing the quality and the quantity of microleakage. The laser microspectral analysis is a punctual method of analysis, which allows to investigate small quantities of materials of around 0.1 ?g. This method allows to establish the content of atoms and molecules and to perform semi-quantitative and quantitative analysis. By this method it is possible to establish trace elements, i. e. with concentration of ppm (parts per million).
Negrutiu, Meda L.; Sinescu, Cosmin; Draganescu, Gheorghe; Todea, Carmen; Dodenciu, Dorin; Rominu, Roxana
OBJECTIVES: This study measured swallowing threshold parameters and nutrient intake in partially dentate subjects rehabilitated by conventional free-end removable partial dentures (RPD) and by RPD over posterior implant retainers and ball attachments (BA). MATERIALS AND METHODS: Eight subjects (two men and six women; mean age 60.1 ± 6.6 years old) received conventional total maxillary dentures and free-end RPD in the mandible. Two months after denture insertion, swallowing threshold and nutrient intake assessments occurred, which included an evaluation of the number of masticatory cycles and medium particle size (X50 ) of a silicone test material (Optocal). A 3-day food diary verified nutrient intake based on a standard Brazilian Food Composition Table. Then, osseointegrated implants were placed bilaterally in the mandibular first molar region, followed by BA, which was fitted in the RPD bases after healing. After 2 months of the RPD over implants and BA use, variables were again assessed. Wilcoxon signed rank tests evaluated the data (P < 0.05). RESULTS: Masticatory cycles did not differ (P > 0.05); however, subjects showed decreased X50 values at the swallowing moment (P = 0.008) and increased daily energy (P = 0.008), carbohydrate (P = 0.016), protein (P = 0.023), calcium (P = 0.008), fiber (P = 0.016), and iron (P = 0.016) intake with RPD implants and BA inserts. No differences were found in fat consumption (P > 0.05). CONCLUSION: Implants and BA retainers over a free-end RPD resulted in smaller swallowed median particle size and improved nutrient intake. PMID:23560748
Campos, Camila Heitor; Gonçalves, Thais Marques Simek Vega; Rodrigues Garcia, Renata Cunha Matheus
This article describes the treatment of a patient for whom a fiber-composite laminate dowel and core and polyethylene fiber were used as a conservative alternative to provide a dowel-and-core and fixed partial denture foundation. The treatment plan included removing the existing restoration on the maxillary right first molar, placing a fiber-reinforced resin dowel and core for retention and reinforcement of the maxillary first premolar, and fabricating a definitive restoration using polyethylene fiber to reinforce the fixed partial denture. PMID:15867748
Ayna, Emrah; Celenk, Sema
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.
Salimi, Hadi; Mosharraf, Ramin; Savabi, Omid
Cobalt-based alloys (Co-Cr-Mo) are usually used in dentistry as frameworks for removable partial dentures. In their basic form these structures function successfully. However, modifications or repairs of the frameworks may reduce their resistance to corrosion and, as a consequence, may provoke biologic reactions in the soft tissues. These reactions may be the result of different types of alloys that contact each other and, in the presence of saliva (based on potential differences), produce a galvanic cell. In this study, a clinical situation after repair of a removable partial denture was examined. The metallographic study of the prosthesis revealed a brazed zone where a gold braze was joining the Co-Cr-Mo framework with a Co-Cr-Ni type alloy (without Mo). The latter revealed signs of corrosion. Various electrochemical parameters (Ecorr, Ecouple, icorr, icouple) of these alloys were analyzed in the laboratory. The Co-Cr-Ni alloy had the lowest nobility and underwent galvanic corrosion in a galvanic couple with gold braze. PMID:8709017
Luthy, H; Marinello, C P; Reclaru, L; Scharer, P
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.
Moslehifard, Elnaz; Farid, Farzaneh
Statement of Problem. Indirect composite or ceramic fixed partial dentures (FPDs) have become an alternative to conventional metal-ceramic adhesive fixed partial dentures (AFPDs). Little information about the adequate restorative material and tooth preparation design for inlay-anchored AFPDs is available to the clinician. Purpose. The purposes of this simulation study were: (1) to use 2-dimensional finite element modeling to simulate stresses
Pascal Magne; Nikolaos Perakis; Urs C. Belser; Ivo Krejci
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
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
PURPOSE The purpose of this study was to investigate the diametral tensile strength of polymer-based temporary crown and fixed partial denture (FPD) materials, and the change of the diametral tensile strength with time. MATERIAL AND METHODS One monomethacrylate-based temporary crown and FPD material (Trim) and three dimethacrylate-based ones (Protemp 3 Garant, Temphase, Luxtemp) were investigated. 20 specimens (ø 4 mm × 6 mm) were fabricated and randomly divided into two groups (Group I: Immediately, Group II: 1 hour) according to the measurement time after completion of mixing. Universal Testing Machine was used to load the specimens at a cross-head speed of 0.5 mm/min. The data were analyzed using one-way ANOVA, the multiple comparison Scheffe test and independent sample t test (? = 0.05). RESULTS Trim showed severe permanent deformation without an obvious fracture during loading at both times. There were statistically significant differences among the dimethacrylate-based materials. The dimethacrylate-based materials presented an increase in strength from 5 minutes to 1 hour and were as follows: Protemp 3 Garant (23.16 - 37.6 MPa), Temphase (22.27 - 28.08 MPa), Luxatemp (14.46 - 20.59 MPa). Protemp 3 Garant showed the highest value. CONCLUSION The dimethacrylate-based temporary materials tested were stronger in diametral tensile strength than the monomethacrylate-based one. The diametral tensile strength of the materials investigated increased with time.
Ha, Seung-Ryong; Yang, Jae-Ho; Lee, Jai-Bong; Han, Jung-Suk
Aim: The record of path of insertion on the dental cast is part of the dentist's work authorization to the dental laboratory technician. The path of insertion record enables the dental technician to replace the cast on a surveyor in the same position that the dentist selected. Analysis of factors that influence the path of insertion should determine a path of insertion that will reduce the potential for dislodgement and promote stability of removable partial denture (RPD). Materials and Methods: The recording of the relation of a cast to a dental surveyor and the transfer of this relationship to the dental laboratory may be done by tripodization, by scoring the base of the cast, or by cementing a reference pin on the cast. Conclusion: Recording the established path of insertion can be difficult when the procedure uses a cemented pin and the casts are mounted in an articulator. This article describes a procedure for innovative dowel pin and sleeve device to record the path of insertion of RPDs, which serves the same purpose as the cemented pin but can be easily removed and replaced. PMID:24992864
Kamble, Vaibhav D; Parkhedkar, Rambhau D
The treatment modality, a continuous occlusal rest removable partial denture, not only restored missing teeth but also stabilized the remaining dentition in a patient with advanced periodontal attachment loss. By engaging the guiding planes at the mesial surfaces of the abutments anteriorly and also the distal surfaces of the abutments posteriorly, the remaining teeth, with varying amounts of mobility, were splinted together by the framework. This conservative treatment option allows flexibility for easy repair during the life span of the prosthesis. PMID:18922254
Ma, Polly S; Brudvik, James S
Resin-bonded fixed partial dentures (RBFPD) are used as a minimal invasive, tooth-preventing alternative for replacing anterior teeth. Zirconia cantilever restorations were supposed to show sufficient strength for a clinical application. The aim of this investigation was to determine the fracture characteristics of cantilever and two-retainer RBFPD, which are fabricated by computer-manufactured high-strength zirconia. Human incisors and canines were used to form three groups of 14 RBFPDs with different types of preparation: group 1, an invasive cantilever; group 2, a minimal-invasive cantilever and group 3, a two-retainer RBFPD control. After thermal cycling and mechanical loading, which was performed to simulate oral service, all restorations were loaded to fracture in a universal testing machine. One half of the specimens were investigated as a control without simulated service. Mode of failure was determined for the three designs. Both cantilever groups showed comparable fracture resistance of 227 N (no. 1) and 210 N (no. 2) before thermal cycling and mechanical loading. The resistance after aging was reduced to 210 N for the invasive cantilever RBFPD and to 179 N for the minimal invasive group. Three-unit RBFPDs showed a significantly higher (p < 0.02) fracture resistance than cantilever bridges before (426 N) as well as after aging (360 N). Predominant failure was FPD and retainer fracture for the invasive cantilever design, debonding for the minimal cantilever design and RBFPD fracture for the two-retainer design. The present study revealed a significantly higher fracture resistance for two-retainer RBFPDs than for cantilever RBFPDs. The frequency of adhesive debonding increased for non-retentive prepared cantilever RBFPDs. PMID:19221810
Rosentritt, Martin; Ries, Stefan; Kolbeck, Carola; Westphal, Maria; Richter, Ernst-Jürgen; Handel, Gerhard
PURPOSE Zirconia has been used in clinical dentistry for approximately a decade, and there have been several reports regarding the clinical performance and survival rates of zirconia-based restorations. The aim of this article was to review the literatures published from 2000 to 2010 regarding the clinical performance and the causes of failure of zirconia fixed partial dentures (FPDs). MATERIALS AND METHODS An electronic search of English peer-reviewed dental literatures was performed through PubMed to obtain all the clinical studies focused on the performance of the zirconia FPDs. The electronic search was supplemented by manual searching through the references of the selected articles for possible inclusion of some articles. Randomized controlled clinical trials, longitudinal prospective and retrospective cohort studies were the focuses of this review. Articles that did not focus on the restoration of teeth using zirconia-based restorations were excluded from this review. RESULTS There have been three studies for the study of zirconia single crowns. The clinical outcome was satisfactory (acceptable) according to the CDA evaluation. There have been 14 studies for the study of zirconia FPDs. The survival rates of zirconia anterior and posterior FPDs ranged between 73.9% - 100% after 2 - 5 years. The causes of failure were veneer fracture, ceramic core fracture, abutment tooth fracture, secondary caries, and restoration dislodgment. CONCLUSION The overall performance of zirconia FPDs was satisfactory according to either USPHS criteria or CDA evaluations. Fracture resistance of core and veneering ceramics, bonding between core and veneering materials, and marginal discrepancy of zirconia-based restorations were discussed as the causes of failure. Because of its repeated occurrence in many studies, future researches are essentially required to clarify this problem and to reduce the fracture incident.
Triwatana, Premwara; Nagaviroj, Noppavan
Fracture of interim fixed partial dentures (FPD) is of important concern to the dental surgeon, especially with long-span fixed partial dentures or areas of heavy occlusal stress. Polymers used in interim FPDs, reinforced with glass fibers have shown to have a positive effect on the fracture resistance of interim FPDs. Since little research has been done on the influence of silane treated glass fibers on the fracture resistance of interim FPDs, this study was conducted to evaluate the effect of silane treatment of glass fibers on the fracture resistance of interim FPDs and its correlation with the position of fiber reinforcement and length of the span of the interim FPD. Interim FPDs were fabricated from an autopolymerizing polymethyl methacrylate (PMMA) resin. Seven FPDs were made in each group. The FPDs in the control group were unreinforced, and in the other groups the FPDs were reinforced either with non silane treated glass fiber or with silane treated glass fiber. The fibers were placed in two different locations in the FPDs. Three length of span of FPDs were tested. The load was applied to the FPD by a steel ball placed in the center of the pontic space. One Way Anova, Two Way Anova, Studentized range test (Scheffe's). Results showed that the load required for fracturing the unreinforced FPDs varied from 272 to 998 N. Mean fracture load of reinforced FPDs varied from 536 to 1642 N. One-way analysis of variance showed that the position of fibers and the silane treatment fibers significantly affected the fracture load. The results of this study suggested that the silane treatment of glass fibers had a marked improvement in the fracture resistance of FPDs as compared to untreated glass fibers. Selective placement of the glass fibers at the undersurface of the pontic and the occlusal surface of the interim fixed partial denture showed more increase in the fracture resistance as compared to the randomly distributed glass fibers. The glass fiber reinforcement is effective in increasing the fracture resistance with the effectiveness most evident in interim FPDs with long spans. With increase in the length of span of interim fixed partial denture the fracture resistance was shown to decrease significantly in all the groups. PMID:22379305
Basant, Gupta; Reddy, Y G
The rotational path of insertion concept for removable partial dentures (RPDs) can be used in esthetically demanding situations. This clinical report describes the treatment of a patient with an anterior maxillary edentulous area using a rotational path RPD. To optimally improve gingival esthetics and to allow proximal retention on the surveyors, a crown-lengthening surgical procedure was performed prior to prosthetic treatment on all teeth involved in this rehabilitation. When correctly planned and fabricated, this prosthesis allows excellent functional and esthetic results, minimizes tooth preparation, and reduces the tendency toward plaque accumulation. PMID:21903542
Goncalves, Leticia Machado; Bezerra-Junior, Jose Ribamar Sabino; Benatti, Bruno Braga; Santana, Ivone Lima
Base metal alloys have been used for over 60 years to cast removable partial denture frameworks. Among other elements, these alloys principally contain nickel, chromium and cobalt, and may be divided into the nickel-containing and nickel-free alloys. Because of the potential biocompatibility hazard created by these and other elements found in the alloys, this group of materials has come under ever increasing scrutiny in the literature. This paper reviews pertinent literature and reports on the findings of a survey on the base metal alloys used in Alberta for the casting of removable partial denture frameworks. PMID:1739881
Wolfaardt, J F; Peters, E
Free-end saddles are liable to be displaced under occlusal pressure. This is as a result of the displaceability of the mucosa. The altered cast technique is employed to try and prevent this by making an impression of the mucosa under controlled pressure. The metal framework was constructed on a cast produced by a mucostatic impression material. Base plates were then constructed in self-cured acrylics on the framework in the saddle areas, and these are close fitting. Border molding was carried out; impression was made with zinc oxide eugenol impression paste.In the laboratory, the free-end saddle areas on the master cast are sectioned off. The denture is then positioned on the model and the new saddle areas are poured. The resulting model represents the free-end saddle areas under conditions, which mimic functional load. Denture construction then continues as normal. The distribution of loading of the free-end saddles is improved and denture is more stable. PMID:22114393
Objective Removable partial dentures (RPD) require different hygiene care, and association of brushing and chemical cleansing is the most recommended to control biofilm formation. However, the effect of cleansers has not been evaluated in RPD metallic components. The aim of this study was to evaluate in vitro the effect of different denture cleansers on the weight and ion release of RPD. Material and Methods Five specimens (12x3 mm metallic disc positioned in a 38x18x4 mm mould filled with resin), 7 cleanser agents [Periogard (PE), Cepacol (CE), Corega Tabs (CT), Medical Interporous (MI), Polident (PO), 0.05% sodium hypochlorite (NaOCl), and distilled water (DW) (control)] and 2 cobalt-chromium alloys [DeguDent (DD), and VeraPDI (VPDI)] were used for each experimental situation. One hundred and eighty immersions were performed and the weight was analyzed with a high precision analytic balance. Data were recorded before and after the immersions. The ion release was analyzed using mass spectrometry with inductively coupled plasma. Data were analyzed by two-way ANOVA and Tukey HSD post hoc test at 5% significance level. Results Statistical analysis showed that CT and MI had higher values of weight loss with higher change in VPDI alloy compared to DD. The solutions that caused more ion release were NaOCl and MI. Conclusions It may be concluded that 0.05% NaOCl and Medical Interporous tablets are not suitable as auxiliary chemical solutions for RPD care.
FELIPUCCI, Daniela N.B.; DAVI, Leticia R.; PARANHOS, Helena F.O.; BEZZON, Osvaldo L.; SILVA, Rodrigo F.; BARBOSA JUNIOR, Fernando; PAGNANO, Valeria O.
PURPOSE: To assess the value of removable partial dentures (RPDs) in subjects with shortened dental arches (SDAs) with regard to quality of life. MATERIALS AND METHODS: Subjects from 2 university dental centers (82 men, 78 women; mean age: 54 +\\/- 18 years) were categorized into the following groups: (1) SDA with intact anterior regions (SDA-1, n = 44); (2) SDA
D. B. Armellini; G. Heydecke; D. J. Witter; N. H. J. Creugers
Provision of partial and complete dentures constructed from resin is commonplace and a satisfactory outcome requires the consideration of the properties of the resin, the oral tissues and prosthodontic principles. This second of a two-part series examines the advantages and disadvantages of flexible nylon denture base resins, which have found popularity for the provision of partial dentures. Adverse effects of denture base resins are examined and the benefits and shortcomings of softliners are explored. Chairside adjustment and polishing, and denture hygiene are also discussed. Clinical Relevance: Knowledge of contemporary denture base resin systems will help to achieve optimal outcomes in removable prosthodontics. PMID:22675889
Rickman, Luke J; Padipatvuthikul, Pavinee; Satterthwaite, Julian D
The relevance of a new generation of monobloc posts and impression copings for implant-supported fixed partial dentures: a 2-year clinical prospective study with the FM-Clip system on EVL implants (SERF).
The use of monobloc posts for implant-supported fixed partial dentures is interesting for biomechanical and biological reasons, but it suffers from a lack of precision during the impression phase. The use of a new generation of monobloc posts associated with individual impression copings with a piston offers a simple and efficient impression procedure for small and medium implant-supported fixed partial dentures. This article presents the FM-Clip system for EVL implants composed of new straight monobloc posts and small impression copings with a piston for precise impressions and easy production of implant-supported fixed partial dentures. PMID:17069170
Leclercq, Philippe; Zenati, Charlotte; Dohan, David M
Mini dental implants (MDIs) in dentistry are recommended for cases with adequate bone quality and height, but a lack of alveolar bone width. Some studies well documented successful usage of MDIs for a removable denture support, but studies of MDIs supporting fixed prosthodontic restorations are scarce. We aimed to study the effect of fixed partial dentures (FPD) therapy supported by MDIs or by MDIs and natural teeth, on patients self perceived oral health related quality of life (OHRQoL), self perceived oral aesthetics and self perceived chewing function. A total of 23 patients (10 female and 13 men, age range from 54 to 78 years) were included and 61 MDIs were inserted, 10 in the maxilla and 51 in the mandible. In 14 patients FPDs were constructed only on MDIs and in 9 patients FPDs were constructed on both, MDIs and natural teeth. FPDs on MDIs were replacing mostly mandibular incisors, the second maxillary incisors and the first maxillary premolars. Those FPDs supported by both, MDIs and natural teeth had some MDIs inserted in frontal regions to allow a FPD construction. The three questionnaires: the OHIP-CRO14 for the assessment of OHRQoL, the OES-CRO for assessment of oral aesthetics and the Chewing function questionnaire (CFQ) for assessment of chewing function have been administrated twice:prior to the MDIs insertion and three months after the FPD treatment supported by MDIs had been finished. The CFQ and the OHIP summary scores significantly decreased revealing better OHRQoL and better chewing ability after treatment, and the OES scores significantly increased indicating increased self perceived oral aesthetics (p < 0.01). Clinical examination revealed no periimplant inflammation. Patients' data supplement the initially promising clinical findings. However, further follow ups will be necessary to finally confirm the long term clinical benefit of MDIs. PMID:24851629
Persi?, Sanja; Palac, Antonija; Vojvodi?, Denis; Celebi?, Asja
This position paper reviews physical and mechanical properties of thermoplastic resin used for non-metal clasp dentures, and describes feature of each thermoplastic resin in clinical application of non-metal clasp dentures and complications based on clinical experience of expert panels. Since products of thermoplastic resin have great variability in physical and mechanical properties, clinicians should utilize them with careful consideration of the specific properties of each product. In general, thermoplastic resin has lower color-stability and higher risk for fracture than polymethyl methacrylate. Additionally, the surface of thermoplastic resin becomes roughened more easily than polymethyl methacrylate. Studies related to material properties of thermoplastic resin, treatment efficacy and follow-up are insufficient to provide definitive conclusions at this time. Therefore, this position paper should be revised based on future studies and a clinical guideline should be provided. PMID:24746524
Fueki, Kenji; Ohkubo, Chikahiro; Yatabe, Masaru; Arakawa, Ichiro; Arita, Masahiro; Ino, Satoshi; Kanamori, Toshikazu; Kawai, Yasuhiko; Kawara, Misao; Komiyama, Osamu; Suzuki, Tetsuya; Nagata, Kazuhiro; Hosoki, Maki; Masumi, Shin-ichi; Yamauchi, Mutsuo; Aita, Hideki; Ono, Takahiro; Kondo, Hisatomo; Tamaki, Katsushi; Matsuka, Yoshizo; Tsukasaki, Hiroaki; Fujisawa, Masanori; Baba, Kazuyoshi; Koyano, Kiyoshi; Yatani, Hirofumi
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
Sectional dentures are constructed in separate parts which join together intra-orally to create a single prosthesis. They are used to exploit undercuts around teeth, hard and soft tissues which require more than one path of insertion, and are usually of split pin or locking bolts design. By using two case studies, we aim to illustrate the provision of sectional dentures and to which situations their uses are best suited. A 30-year-old male was referred to the Department of Prosthetics at the Birmingham Dental Hospital for a replacement upper partial cobalt chrome denture of a Kennedy Class IV bounded saddle. The patient had a history of failed upper cobalt chrome removable partial dentures owing to loss of retention and poor stability over the previous 12 months. A 40-year-old female patient was referred by her GDP for restoration of a bounded saddle in the lower right quadrant with a history of intolerance to previous dentures. These two cases demonstrate the successful use of sectional dentures in the aesthetic zone. Although more technically demanding, they lie well within the scope of general practice and offer patients alternative solutions from dental implants and bridgework. These cases highlight the importance of the use of alternative prosthetic techniques which can be simple and achievable for all practitioners. Clinical Relevance: Sectional dentures are a treatment modality for the edentulous space where the presence of one or more undercuts prevents restoration by more conventional techniques. This paper highlights some of the situations in which sectional dentures can be employed and emphasizes their use in general practice. PMID:22675891
Karir, Naveen; Hindocha, Vishali; Walmsley, A Damien
It is well known that shortened dental arch decreases masticatory function. However, its potential to change brain activity during mastication is unknown. The present study investigates the effect of a shortened posterior dental arch with mandibular removable partial dentures (RPDs) on brain activity during gum chewing. Eleven subjects with missing mandibular molars (mean age, 66.1 years) on both sides received experimental RPDs with interchangeable artificial molars in a crossover trial design. Brain activity during gum chewing with RPDs containing (full dental arch) and lacking artificial molars (shortened dental arch) was measured using functional magnetic resonance imaging. Additionally, masticatory function was evaluated for each dental arch type. Food comminuting and mixing ability and the perceived chewing ability were significantly lower in subjects with a shortened dental arch than those with a full dental arch (P < 0.05). Brain activation during gum chewing with the full dental arch occurred in the middle frontal gyrus, primary sensorimotor cortex extending to the pre-central gyrus, supplementary motor area, putamen, insula and cerebellum. However, middle frontal gyrus activation was not observed during gum chewing with the shortened dental arch. These results suggest that shortened dental arch affects human brain activity in the middle frontal gyrus during gum chewing, and the decreased middle frontal gyrus activation may be associated with decreased masticatory function. PMID:24697794
Shoi, K; Fueki, K; Usui, N; Taira, M; Wakabayashi, N
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.
Bortolotto, Tissiana; Monaco, Carlo; Onisor, Ioana; Krejci, Ivo
Denturism, an organized movement by dental laboratory technicians to increase their control over the provision of denture services to the public, has generated a great deal of controversy among members of organized dentistry, the National Denturist Association, the Federal Trade Commission, consumer groups, and prepaid dental plans. Denturism is currently legal in Arizona, Colorado, Maine, and Oregon. In the first three States, the denturist must practice under the supervision of a dentist, but in Oregon the denturist is able to enter independent practice. The American Dental Association has held that a denturist is educationally unqualified to provide denture services directly to the consumer, Representatives of organized dentistry have characterized denturists as untrained and unskilled persons who would endanger the public's health and return one phase of dentistry to the apprentice system. They see denturism as constituting a major step backward in health care delivery and having an adverse effect on preventive dental care. The National Denturist Association, however, defines a denturist as a highly skilled person who specializes in the making of full and partial dentures. Denturists maintain that the dentist is an unnecessary middleman in the provision of denture services and is the primary cause of the high cost of dental prostheses. They contend that State dental laws providing that only dentists may render denture services have led to the high cost of these services without contributing significantly to the health and safety of the public. Organized dentistry in the United States has been fighting denturism in a number of ways. One that has met with considerable success has been the establishment of programs to provide people access to dental care, especially denture services, at lower costs. A second alternative under consideration is to license denturists but require them to practice under the supervision of a dentist. A third alternative under discussion is to expand the duties of existing dental auxiliary personnel. The final decision on denturism, however, will not be made by the dental profession or the denturists, but by the voting public and their elected representatives, based on the evidence they have before them.
Flanders, Raymond A.
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
PURPOSE: To evaluate 1-year implant survival and marginal bone loss around implants that support fixed partial dentures loaded immediately or after 3 months, and effects from abutment usage. MATERIALS AND METHODS: In this 2005 to 2009 randomized, parallel-group, clinical trial, 50 partially edentulous patients each received three Brånemark TiUnite™ implants (Nobel Biocare®, Göteborg, Sweden), mostly in the posterior maxilla. Two implants were fitted with abutments: a TiUnite™ surface and a machine-milled surface; the suprastructure was attached directly at implant level for the third implant. After randomized allocation, implants were immediately loaded with a fixed temporary bridge (test group) or left unloaded for 3 months (control group). A permanent fixed suprastructure replaced the temporary bridge after 6 months (test). Hard and soft tissues were examined during pretreatment and surgery plus 2 days, 14 days, 4 weeks, 3 months, and 1 year after surgery. RESULTS: After 1 year, four implants were lost in the test and two in the control groups (1-year survival rates of 94.9% [test] and 97.2% [control], with no significant intergroup difference). Resonance frequency analysis values indicated a similar pattern in both groups, with implant stability quotient (ISQ) reduction between 2 and 4 weeks. The test group had a significantly lower ISQ than the control group at these appointments. After 1 year, marginal bone losses around the implants were, on average, 1.32?mm (test, standard error of the mean [SEM] 0.08) and 1.24?mm (control, SEM 0.08), with no significant intergroup difference. Significantly larger marginal bone loss was observed at implants without abutment compared with implants with abutment. CONCLUSIONS: For both groups, this study showed similar implant survival rates and marginal bone loss. Larger bone loss was found at implants loaded without attached abutments. PMID:23295099
Göthberg, Catharina; André, Ulrika; Gröndahl, Kerstin; Ljungquist, Birgit; Thomsen, Peter; Slotte, Christer
The use of resilient denture liners in complete denture construction has become increasingly popular for providing comfort for denture wearers. The primary disadvantage of these materials is that the physical and mechanical properties change rapidly with time in a service environment. The purpose of this study is to evaluate the color stability of five commercially available soft denture liners as a function of accelerated aging. Color measurements were made before aging with a colorimeter and data processor. The samples were then weathered for 100 hours in an accelerated aging chamber in the presence of a xenon ultraviolet visible-light source, an intermittent water spray at 110 degrees F, and 90% humidity. After aging, color measurements were made again and color differences (delta E) were calculated. Results were statistically tested with analysis of variance and Scheffé intervals were calculated at 0.96. It was concluded that accelerated aging can be used to evaluate color stability of soft denture liners. PMID:1432811
Shotwell, J L; Razzoog, M E; Koran, A
The purposes of this study were to photoelastically measure the biomechanical behavior of 4 implants retaining different cantilevered bar mandibular overdenture designs and to compare a fixed partial denture (FPD). A photoelastic model of a human edentulous mandible was fabricated, which contained 4 screw-type implants (3.75 × 10 mm) embedded in the parasymphyseal area. An FPD and 3 overdenture designs with the following attachments were evaluated: 3 plastic Hader clips, 1 Hader clip with 2 posterior resilient cap attachments, and 3 ball/O-ring attachments. Vertical occlusal forces of 100 N were applied between the central incisor and unilaterally to the right and left second premolars and second molars. Stresses that developed in the supporting structure were monitored photoelastically and recorded photographically. The results showed that the anterior loading, the overdenture with 3 plastic Hader clips, displayed the largest stress concentration at the medium implant. With premolar loading, the FPD and overdenture with 3 plastic Hader clips displayed the highest stresses to the ipsilateral terminal implant. With molar loading, the overdenture with 3 ball/O-ring attachments displayed the most uniform stress distribution in the posterior edentulous ridge, with less overloading in the terminal implant. It was concluded that vertical forces applied to the bar-clip overdenture and FPD created immediate stress patterns of greater magnitude and concentration on the ipsilateral implants, whereas the ball/O-ring attachments transferred minimal stress to the implants. The increased cantilever in the FPD caused the highest stresses to the terminal implant. PMID:22067869
Mazaro, José Vitor Quinelli; Filho, Humberto Gennari; Vedovatto, Eduardo; Pellizzer, Eduardo Piza; Rezende, Maria Cristina Rosifini Alves; Zavanelli, Adriana Cristina
The aim of this study was to evaluate the biomechanical behavior of a mandibular distal extension removable partial denture (DERPD) associated with an implant and different retention system, by bidimensional finite element method. Five hemimandible models with a canine and external hexagon implant at second molar region associated with DERPD were simulated: model A, hemimandible with a canine and a DERPD; model B, hemimandible with a canine and implant with a healing abutment associated to a DERPD; model C, hemimandible with a canine and implant with an ERA attachment associated to a DERPD; model D, hemimandible with a canine and implant with an O'ring attachment associated to a DERPD; and model E, hemimandible with a canine and implant-supported prosthesis associated to a DERPD. Cusp tips were loaded with 50 N of axial or oblique force (45 degrees). Finite element analysis was performed in ANSYS 9.0. model E showed the higher displacement and overload in the supporting tissues; the patterns of stress distribution around the dental apex of models B, C, and D were similar. The association between a DERPD and an osseointegrated implant using the ERA or O'ring systems shows lower stress values. Oblique forces showed higher stress values and displacement. Oblique forces increased the displacement and stress levels in all models; model C displayed the best stress distribution in the supporting structures; healing abutment, ERA, and O'ring systems were viable with RPD, but DERPD association with a single implant-supported prosthesis was nonviable. PMID:20485037
Pellizzer, Eduardo Piza; Verri, Fellippo Ramos; Falcón-Antenucci, Rosse Mary; Goiato, Marcelo Coelho; Gennari Filho, Humberto
Background and aims The mechanical properties of fiber-reinforced composite fixed partial dentures (FPDs) are af-fected by fiber impregnation. The aim of this in vitro study was to compare the fracture resistance of composite fixed partialdentures reinforced with pre-impregnated and non-impregnated fibers. Materials and methods Groups (n=5) of three-unit fiber-reinforced composite FPDs (23 mm in length) from maxillary second premolar to maxillary second molar were fabricated on two abutments with pontic width of 12 mm. One group was fabricated as the control group with composite (Gradia) and the other two groups were fabricated with composite (Gradia) reinforced with pre-impregnated fiber (Fibrex ribbon) and non-impregnated fiber (Fiber braid), respectively. The specimens were stored in distilled water for one week at 37°C and then tested in a universal testing machine by means of a three-point bending test. Statistical analysis consisted of one-way ANOVA and a post hoc Scheffé’s test for the test groups (?=0.05). Results Fracture resistance (N) differed significantly between the control group and the other two groups (P<0.001), but there were no statistically significant differences between the pre-impregnated and non-impregnated groups (P=0.565). The degree of deflection measured (mm) did not differ significantly between the three groups (P=0.397), yet the mean deflection measured in pre-impregnated group was twice as that in the other two groups. Conclusion Reinforcement of composite with fiber might considerably increase the fracture resistance of FPDs; how-ever, the type of the fiber used resulted in no significant difference in fracture resistance of FPD specimens.
Mosharraf, Ramin; Torkan, Sepideh
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
This study compared the levels of biofilm in maxillary and mandibular complete dentures and evaluated the number of colony-forming units (cfu) of yeasts, after using auxiliary brushing agents and artificial saliva. Twenty-three denture wearers with hyposalivation and xerostomia were instructed to brush the dentures 3 times a day during 3 weeks with the following products: Corega Brite denture dentifrice, neutral liquid soap, Corega Brite combined with Oral Balance (artificial saliva) or tap water. For biofilm quantification, the internal surfaces of the dentures were disclosed, photographed and measured using a software. For microbiological analysis, the biofilm was scrapped off, and the harvested material was diluted, sown in CHROMagar™ Candida and incubated at 37°C for 48?h. Data were analyzed statistically by two-way ANOVA and Tukey's test (?=0.05). Mandibular dentures presented a mean biofilm percentage (µ=26.90 ± 21.10) significantly greater than the maxillary ones (µ=18.0 ± 15.0) (p<0.05). Brushing using Corega Brite combined with Oral Balance (µ=15.87 ± 18.47) was more effective (p<0.05) than using the denture dentifrice (µ=19.47 ± 17.24), neutral soap (µ=23.90 ± 18.63) or tap water (control; µ=32.50 ± 20.68). For the microbiological analysis, the chi-square test did not indicate significant difference between the hygiene products for either type of denture. The more frequently isolated species of yeasts were C. albicans, C. tropicalis and C. glabrata. In conclusion, mandibular dentures had more biofilm formation than maxillary ones. Denture brushing with Corega Brite dentifrice combined with the use of Oral Balance was the most effective method for reduction of biofilm levels, but the use of products did not show difference in yeast cfu counts. PMID:23657413
Paranhos, Helena de Freitas Oliveira; Salles, Antônio Eduardo Sparça; Macedo, Leandro Dorigan de; Silva-Lovato, Cláudia Helena da; Pagnano, Valéria Oliveira; Watanabe, Evandro
Denture stomatitis (DS) is a fungal infection characterized by inflammation of the oral mucosa in direct contact with the denture and affects up to 50% of denture wearers. Despite the prevalence, very little is known about the role of fungal or host factors that contribute to pathogenesis. Recently, we developed a novel intraoral denture system for rodent research. This denture system consists of custom-fitted fixed and removable parts to allow repeated sampling and longitudinal studies. The purpose of this study was to use this denture system to develop a clinically relevant animal model of DS. To establish DS, rats were inoculated with pelleted Candida albicans, which resulted in sustained colonization of the denture and palate for 8 weeks postinoculation. Biofilm formation on the denture was observed by week 4 and on the palate by week 6 postinoculation. Rats were monitored for clinical signs of disease by assigning a clinical score after macroscopic examination of the palate tissue according to Newton's method. By week 4 postinoculation, the majority of inoculated rats with dentures exhibited a clinical score of 1 (pinpoint erythema). By week 6 and week 8 postinoculation, increasing percentages of rats exhibited a clinical score of 2 (diffuse erythema/edema). Histological analysis of palate tissue demonstrated progressively increasing inflammatory cell recruitment throughout the time course of the infection. Palatal biofilm formation was commensurate with development of palatal erythema, which suggests a role for biofilm in the inflammatory response.
Johnson, Clorinda C.; Yu, Alika; Lee, Heeje; Fidel, Paul L.
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
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
Over the last decade, there has been a dramatic rise in patients' esthetic expectations with regard to both conventional and implant prosthodontics. The loss of hard and/or soft tissue dimensions, often unpredictably, around implants, can result in potential embarrassment due to the display of metal components. Patients are understandably reluctant to accept visibility of metal abutments and/or the implant substructures, especially in the esthetic zone, even if biologically sound. The use of 1-piece zirconia implant frameworks or, alternatively, custom zirconia abutments with a zirconia framework, has enabled both a good biological response as well as the ability to improve the esthetic outcome. This clinical report demonstrates the use of a 1-piece zirconia implant-supported fixed partial denture in the anterior maxilla, with minimal soft tissue dimension above the implant shoulder level, which dictated the need for prosthetic soft tissue augmentation. PMID:19033025
Dunn, David B
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
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 ...
The aim of this clinical trial was to assess satisfaction, as well as the frequency and type of prosthetic complications in terms of several variables, in patients with complete dentures that had been supplied at private clinics. The study subjects were 64 patients with a mean age of 63.48 years wearing complete dentures provided at private clinics, and requesting new ones. The degree of patient satisfaction with their dentures was assessed, as well as complications and parameters related to the dentures such as the accuracy of vertical dimensions and centric relation, arrangement and possible malposition of the artificial teeth, and the border length of the denture bases. The most common complication was loss of retention (85.9%), followed by ulceration (44.2%). Mandibular dentures with long vestibular borders showed a significantly higher incidence of epulis fissuratum (P = 0.017), and denture-related sore spots influenced patients' speech ability (P = 0.023). Routine recalls seem to be important for wearers of complete dentures, as several insidious complications may develop and cause damage to the dentures as well as the patients' oral tissues. PMID:23485598
Bilhan, Hakan; Geckili, Onur; Ergin, Selen; Erdogan, Ozge; Ates, Gokcen
Treatment options for patients with severe attrition resulting in reduced occlusal vertical dimension are often limited to fixed prosthesis to reestablish proper occlusal vertical dimension and functional occlusion. In some cases such as when there are limited finances, minimal esthetic concerns, and medical considerations fixed prosthesis may not be the ideal treatment option. Overlay removable partial dentures (ORPDs) can be used as a provisional or interim prosthesis as well as permanent prosthesis in these cases. While ORPDs can provide a reversible and relatively inexpensive treatment for patients with a significantly compromised dental status, there is not much scientific evidence in the literature on ORPDs. Most studies published on ORPDs to date are primarily reviews and clinical reports. In this article, literatures on ORPDs are summarized and a patient treated with interim and permanent ORPDs is presented. This article reviews previously published literatures on the use of ORPDs. Indications, advantages and disadvantages are discussed. Treatment protocol with an example of the prosthodontic treatment of a patient with severely worn dentition with an interim ORPD and later a permanent ORPD are discussed in details. PMID:19915723
Patel, Mit B; Bencharit, Sompop
The mucosa that covers the residual ridges of edentulous patients may present some distortion or displacement when occlusal loading is applied in complete dentures. This distortion and movement of the denture can result in acceleration of residual ridge resorption and loss of retention and stability. The aim of this study was to analyze the pattern of upper complete denture movement related to underlying mucosa displacement. A sample of 10 complete denture wearers was randomly selected, which had acceptable upper and lower dentures and normal volume and resilience of residual ridges. The kinesiographic instrument K6-I Diagnostic System was used to measure denture movements, according to the method proposed by Maeda et al.7, 1984. Denture movements were measured under the following experimental conditions: (A) 3 maximum voluntary clenching cycles and (B) unilateral chewing for 20 seconds. The results showed that under physiological load, oral mucosa distortion has two distinct phases: a fast initial displacement as load is applied and a slower and incomplete recovery when load is removed. Intermittent loading such as chewing progressively reduces the magnitude of the denture displacement and the recovery of the mucosa is gradually more incomplete. PMID:15107919
Compagnoni, Marco Antonio; de Souza, Raphael Freitas; Leles, Cláudio Rodrigues
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
Cooper, R L; Constable, I J
METHODS. Twenty children (13.1 6 0.9 years of age) were recruited who had successfully worn tinted lenses for at least 6 months and were compared with an age-matched control group (12.6 6 2.2 years of age) of 21 children who were not lens wearers. A range of psychophysical tasks was adapted to identify specific anomalous visual perceptions. Spatiotemporal contrast sensitivity
Anita J. Simmers; Peter J. Bex; Fiona K. H. Smith; Arnold J. Wilkins
Denture stomatitis presents as a chronic disease in denture-bearing patients, especially under maxillary prosthesis. Despite the existence of a great number of antifungal agents, treatment failure is observed frequently. Propolis, a natural bee product, possesses well-documented antifungal and anti-inflammatory activities. The purpose of this study was to evaluate the clinical efficacy of a new Brazilian propolis gel formulation in patients diagnosed with denture stomatitis. Thirty complete-denture wearers with denture stomatitis were enrolled in this pilot study. At baseline, clinical evaluation was performed by a single clinician and instructions for denture hygiene were provided. Fifteen patients received Daktarin (Miconazole gel) and 15 received Brazilian propolis gel. All patients were recommended to apply the product four times a day during one week. Clinical evaluation was repeated by the same clinician after treatment. All patients treated with Brazilian propolis gel and Daktarin had complete clinical remission of palatal edema and erythema. This new Brazilian propolis gel formulation had efficacy comparable to Daktarin and could be an alternative topical choice for the treatment of denture stomatitis. PMID:18696746
Santos, Vagner R; Gomes, Rafael T; de Mesquita, Ricardo A; de Moura, Mariela D G; França, Esdras C; de Aguiar, Evandro G; Naves, Marcelo D; Abreu, José A S; Abreu, Sheila R L
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.
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
The aim of the article is to assist practitioners in the diagnosis and management of complete denture problems by addressing the problems from a theoretical viewpoint and in a clinically diagnostic way. Clinical Relevance: To assist practitioners and undergraduates to understand the clinical basis of complete denture prosthodontics. PMID:24839714
McCord, J Fraser; Smith, Philip; Jauhar, Sachin
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
Aim: To determine the incidence of non-severe keratitis (NSK) and severe keratitis (SK) among wearers of current generation contact lenses.Methods: A 12 month, prospective, hospital based epidemiological study was conducted by examining all contact lens wearers presenting with a corneal infiltrate\\/ulcer to a hospital centre in Manchester. A clinical severity matrix was used to differentiate between NSK and SK, based
P B Morgan; N Efron; E A Hill; M K Raynor; M A Whiting; A B Tullo
When multiple tooth loss causes loss of occlusal-masticatory function, functional recovery is normally obtained with the help of removable dentures. After resection of the jawbone or tongue because of tumors, the movement of the tongue and its surrounding tissues is limited, and patients exhibit a more pronounced loss of chewing and swallowing than that observed in other cases of multiple tooth loss. In such cases, it is necessary to take extra care in determining the position of the mandible, arrangement of artificial teeth, and morphology of the palate. In the present case, the left lower jawbone was resected because of a gingival tumor, and when the new denture was manufactured, the intercuspal position was based on the resting position of the mandible. The stability of the lower complete denture was a priority and the artificial teeth were partially arranged on the lingual side. The new denture, however, caused insufficient closing of the mouth aperture and insufficient impact between tongue and palate, resulting in dysphagia. Therefore, the vertical dimension of occlusion was reduced multiple times to improve chewing and swallowing function. PMID:23318922
Hotta, Hiromi; Kanai, Yuki; Yamashita, Shuichiro
Objective: This study presents the incidence of denture impaction in the oesophagus, and discusses the difficulties of managing such cases. Method: A total of 262 patients with a history of foreign body ingestion (between 1999 and 2010) were reviewed; 46 of these patients had dentures impacted in the oesophagus. Results: The cervical section of the oesophagus was the commonest site of impaction. Dysphagia and tracheal tenderness were the most consistent features when dentures became impacted in the upper oesophagus. In most cases, rigid oesophagoscopy enabled successful removal of the impacted denture. Locating an impacted denture hidden within the oesophageal mucosal folds sometimes proved difficult. Conclusion: In cases of impacted dentures in the oesophagus, a positive history helps in the diagnosis, but a high degree of clinical suspicion aids early detection. Conventional radiographs are important but may not always be of assistance. Early intervention reduces complications. Dentures that are poorly maintained and old are more likely to be swallowed accidentally. The inclusion of radiopaque filler within dentures would assist localisation following accidental swallowing. PMID:24759356
Bandyopadhyay, S N; Das, S; Das, S K; Mandal, A
The pre-prosthetic treatments of two female patients with osteoarthritis of the temporomandibular joints were presented in this paper. In the first case report, an 83-year-old patient wore complete dentures (CDs) for 30 years. The second patient (71 years of age) wore a three-year-old upper CD and a lower removable partial denture with a two-unit fixed dental prosthesis. Pain was successfully eliminated by the stabilization splint on the upper CD. Magnetic resonance imaging was used to confirm the diagnosis and clinical follow-up of the splint treatment. PMID:22474931
Badel, T; Jerolimov, V; Marotti, M; Krolo, I
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 and disseminated diseases in immunosuppressed humans. Neutrophils play a critical role in the immune response against C. albicans and are continually present in the salivary fluid and in the blood. The aim of this study was to determine ageing-related changes in salivary and blood neutrophils and their potential implications in Candida-related denture stomatitis. Results Our results showed a lower number of neutrophils in the saliva from patients presenting Candida-related denture stomatitis in comparison to their matched controls. Furthermore, fewer neutrophils were isolated from the saliva of aged control individuals in comparison to matched younger subjects. CXCR1, CD62L and CD11b expression were significantly greater on systemic neutrophils from younger control individuals. Elderly individuals showed more apoptotic salivary neutrophils and lower GM-CSF levels than younger ones, regardless of the occurrence of Candida infection. On the other hand, CXCL-8 concentrations were higher in the saliva from elderly individuals. Besides, TNF-? was detected at elevated levels in the saliva from infected elderly subjects. Salivary neutrophils from elderly and young patients presented impaired phagocytic activity against C. albicans. However, just systemic neutrophils from elderly showed decreased phagocytosis when compared to the younger ones, regardless of the occurrence of infection. In addition, neutrophils from aged individuals and young patients presented low fungicidal activity. Conclusion The data suggests that the Candida related-denture stomatitis is associated to neutrophils function deficiency, and ageing drastically appears to alter important characteristics of such cells, facilitating the establishment of this infection.
Gasparoto, Thais Helena; Vieira, Narciso Almeida; Porto, Vinicius Carvalho; Campanelli, Ana Paula; Lara, Vanessa Soares
The aim of this study was to evaluate the clinical long-term performance of a visible light-cured resin (VLCR) denture base material and to compare it to a well-established polymethylmethacrylate (PMMA)-based denture acrylic in a randomized split-mouth clinical long-term study. One hundred removable partial dentures in 90 patients, with at least two saddles each, were investigated. One saddle was made of VLCR, while the other was made of PMMA at random. Plaque adhesion, tissue reaction, and technical parameters of the dentures were assessed 6, 12, and 18 months after treatment. Statistical analysis was performed using the Wilcoxon rank-sum test. Though VLCR showed higher plaque adhesion than PMMA after 6, 12, and 18 months (p < 0.001), there were no important differences with regard to tissue reaction. Concerning plaque adhesion, surface quality with regard to the lower side, interfaces between denture acrylic and metal and the boundary between denture acrylic and denture tooth PMMA was rated higher than VLCR. The surface quality of the upper side of the denture saddles showed no significant differences (p > 0.05). Neither VLCR nor PMMA showed discoloration at any point in time (p > 0.05). It can be concluded that VLCR is a viable alternative for the production of removable dentures. Especially in patients with hypersensitivities to PMMA, VLCR is particularly suitable for clinical use. PMID:21655910
Gohlke-Wehrße, Hanna-Lena; Giese-Kraft, Katja; Wöstmann, Bernd
Visible light-cured composite resins have become popular in prosthetic dentistry for the replacement of fractured/debonded denture teeth, making composite denture teeth on partial denture metal frameworks, esthetic modification of denture teeth to harmonize with the characteristics of adjacent natural teeth, remodelling of worn occlusal surfaces of posterior denture teeth etc. However, the researches published on the bond strength between VLC composite resins and acrylic resin denture teeth is very limited. The purpose of this study is to investigate the effect of five different methods of surface treatments on acrylic resin teeth on the shear bond strength between light activated composite resin and acrylic resin denture teeth. Ninety cylindrical sticks of acrylic resin with denture teeth mounted atop were prepared. Various treatments were done upon the acrylic resin teeth surfaces. The samples were divided into six groups, containing 15 samples each. Over all the treated and untreated surfaces of all groups, light-cured composite resin was applied. The shear strengths were measured in a Universal Testing Machine using a knife-edge shear test. Data were analyzed using one way analysis of variance (ANOVA) and mean values were compared by the F test. Application of bonding agent with prior treatment of methyl methacrylate on the acrylic resin denture teeth resulted in maximum bond strength with composite resin. PMID:22379301
Chatterjee, Nirmalya; Gupta, Tapas K; Banerjee, Ardhendu
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.
Kumar, Sandeep; Arora, Aman; Yadav, Reena
Candida albicans is a dimorphic yeast strongly gram positive able to live as normal commensal organism in the oral cavity of healthy people. It is the yeast more frequently isolated in the oral cavity. Under local and systemic factors related to the host conditions, it becomes virulent and responsible of oral diseases known as oral candidiasis. It has been shown that the presence of denture is a predisposing factor to the onset of pathologies related to C. albicans. Clinical studies have shown that C. albicans is not only able to adhere to the mucous surfaces, but also to stick to the acrylic resins of the dental prostheses. Both the plaque accumulated on the denture and the poor oral hygiene contribute to the virulence of Candida, offering the clinical picture of Candida-associated denture stomatitis. The therapeutic strategies currently adopted in the clinical practice to overcome these fungal infections provide for the use of topical and/or systemic antifungal and topical antiseptics and disinfectants, the irradiation with microwaves and the accurate mechanical removal of the bacterial plaque from the denture surfaces and from the underlying mucosa. A correct oral hygiene is important for the control of the bacterial biofilm present on the denture and on the oral mucosa and it is the fundamental base for the prophylaxis and the therapy of the Candida-associated denture stomatitis. PMID:20711156
Salerno, Carmen; Pascale, Michelangelo; Contaldo, María; Esposito, Vincenzo; Busciolano, Maurizio; Milillo, Lucio; Guida, Agostino; Petruzzi, Massimo; Serpico, Rosario
The aim of the present clinical report was to describe the use of a patient's extensive fixed prosthesis, where the supporting teeth were hopeless, for fabricating an interim immediate complete denture. The present procedure was used to replicate the vertical dimension, phonetic and aesthetic of the existing fixed prostheses as part of an immediate denture and a final complete denture. PMID:24611094
Caputi, Sergio; Murmura, Giovanna; Ricci, Laura; Varvara, Giuseppe; Sinjari, Bruna
Summary The aim of the present clinical report was to describe the use of a patient’s extensive fixed prosthesis, where the supporting teeth were hopeless, for fabricating an interim immediate complete denture. The present procedure was used to replicate the vertical dimension, phonetic and aesthetic of the existing fixed prostheses as part of an immediate denture and a final complete denture.
Caputi, Sergio; Murmura, Giovanna; Ricci, Laura; Varvara, Giuseppe; Sinjari, Bruna
Purpose: To determine whether tear osmolarity contributes to the assessment of the ocular surface in soft contact lens (CL) wearers. Methods: Prospective, case-control series in 44 CL wearers (28 tolerant and 16 intolerant) and 34 healthy subjects. Every patient underwent a thorough ophthalmic examination with a tear osmolarity test (TearLab System), conjunctival impression cytology and meibomian lipid sampling. Symptoms, break-up time (BUT), tear osmolarity, conjunctival expression of HLA-DR and meibomian fatty acid composition were evaluated. Results: Tear osmolarity did not differ between controls and CL wearers (p?=?0.23). Flow cytometry results expressed in antibody-binding capacity (ABC) units and percentage of positive cells revealed a significant difference between the intolerant CL wearer group and the control group (p?0.0001). Comparisons between tolerant and intolerant CL wearers showed only a significant difference for mean fluorescence levels expressed in ABC units (p?0.0001). The BUT was significantly shorter in intolerant and tolerant CL wearers subjects than in healthy subjects (p?0.0001), whereas there was no significant difference in meibomian fatty acid composition (p?=?0.99) between the two groups. Conclusion: Contact lens wear is responsible for ocular surface alterations whose patterns are very similar to those reported in early dry-eye syndrome. However, tear osmolarity was not modified in these selected CL wearers. The yield of tear osmolarity with TearLab™ in assessing ocular surface disorders in CL wearers deserves further investigation. PMID:23506409
Muselier-Mathieu, Aurore; Bron, Alain M; Mathieu, Bénigne; Souchier, Maxime; Brignole-Baudouin, Françoise; Acar, Niyazi; Brétillon, Lionel; Creuzot-Garcher, Catherine
Goal: To measure change in a quality of life after treatment with removable dentures and to describe differences in quality of life in patients with new and worn out dentures. Materials and methods: Measuring instrument was OHIP-49, translated from English into one of the languages in Bosnia-Herzegovina. Sample consisted of patients who wanted to make/replace mobile dentures or came to repair a broken dentures. Comprehensibility of the OHIP-BH49 was tested on a sub-sample of patients. Three measurements were made: before and after the insertion of dentu res and when patients came to repair their mobile dentures. Results: Sample consisted of 67 patients: 32 patients who sought prosthetic treatment, and 35 who came to repair their broken dentures. We received 89.7% correctly filled questionnaires. Minor changes were made in four (4) questions. Statistical analysis performed with the T-test revealed the significant differences, before and after the treatment with mobile dentures (t=39.5, p<0.001). There was a significant difference in OHIP scores in patients with a new dentures, compared to the patients who had worn out dentures (t=44.30, p<0.001). Substantial differences, between OHIP scores, regarding the time of wearing dentures or patients’ age were not observed. Discussion: Patients who wore dentures longer than 5 years, showed better quality of life, because they became accustomed to the dentures. Conclusions: Self-reported life quality improved considerably after insertion of a new dentures. Patients with a new dentures showed significantly better quality of life than patients with worn out dentures. One part of OHIP validation in Bosnia-Herzegovina has been done.
Study casts on thirty-five partially edentulous patients were analysed at their arch level and at the interarch levels. At the arch level the crest of the residual ridge is located lingually to the position of the remaining teeth in the maxilla as well as in the mandible. The spatial interarch relationship between the residual edentulous ridge and the antagonist natural teeth in the buccolingual plane indicated that the crest of the residual ridge is lingual to the occlusal surfaces of the antagonist teeth. In the maxilla the positioning of the artificial teeth in the area previously occupied by the natural extracted teeth will place the denture teeth far buccal as well as away from the crest of the residual ridge. Other possibilities are to place the artificial teeth in a cross bite relation or to eliminate the buccal cusps of the replacement teeth. In the mandible the denture teeth can be placed at the position occupied formerly by the natural teeth. PMID:268416
Pietrokovski, J; Mejias, J E
Purpose Multifactorial etiological factors contribute to denture stomatitis (DS), a type of oral candidiasis; however, unlike other oral candidiasis, DS can occur in a healthy person wearing a denture. In this study, we therefore attempt to explore the association between candida, denture, and mucosal tissue using 1) exfoliative cytology, 2) the candidal levels present in saliva, on mucosal tissues and on denture surfaces, and 3) the salivary flow rate and xerostomic symptoms. Materials and Methods A cross-sectional study enrolled 32 edentulous participants, 17 without DS as controls and 15 with DS (Newton’s classification type II and III). Participants with systemic or other known oral conditions were excluded. Participants completed a xerostomia questionnaire, and salivary flow rates were measured. Samples of unstimulated whole saliva (UWS) and stimulated whole saliva (SWS) were collected. UWS was used for fungal culturing. Periodic acid-Schiff (PAS) stain and quantitative exfoliative cytology were performed on samples from affected and unaffected mucosa from each participant. Levels of Candida species (albicans and non-albicans) were determined in salivary samples (expressed as colony-forming units, CFU), as well as from swab samples obtained from denture fitting surfaces, in addition to affected and unaffected mucosa. Results There were no significant differences in salivary flow rates, mucosal wetness, or frequency of reported dry mouth comparing participants with and without DS. Exfoliative cytology of mucosal smears demonstrated significantly higher (P = 0.02) inflammatory cell counts in DS patients, as compared with smears of healthy denture-wearers. C. albicans was significantly more prevalent in saliva (P = 0.03) and on denture surfaces (P = 0.002) of DS participants, whereas mucosal candidal counts and the presence of cytological hyphae did not show significant difference comparing DS to healthy participants. Conclusions In this investigation, we presented a unique group of healthy edentulous patients. This population may reflect the general DS population without systemic or other oral diseases. The prominent etiological factor for DS in this population is the presence of candida in denture and saliva. We found that other factors such as saliva flow/xerostomia, fitting of the denture, and the presence of candida in the mucosa, are less important in this population. Therefore, DS treatments in healthy patients should first focus on sanitization of an existing denture and/or fabrication of a new denture.
AlTarawneh, Sandra; Bencharit, Sompop; Mendoza, Luisito; Curran, Alice; Barrow, David; Barros, Silvana; Preisser, John; Loewy, Zvi G.; Gendreau, Linda; Offenbacher, Steven
A major problem commonly observed in denture wearer is the detachment of artifcial tooth/teeth from acrylic denture base. The problem was grave when porcelain teeth used along with the then available denture base materials. The bond formed was purely mechanical and hence debonding of teeth from denture base was a frequent occurrence. Inspite of chemical union between acrylic resin teeth and acrylic denture base material, detachment of teeth particularly anterior teeth is a frequent observation. The objective of the study is to study the effect of change in the surface treatment and surface confguration of ridge lap surface of the teeth on retention of cross-linked acrylic teeth on cross-linked acrylic resin denture base. Sixty specimens were tested for the shear compressive bond strength using instron universal testing machine in KN. Statistical analysis is used. The fndings were analyzed using one-way analysis of variance (ANOVA) and 't' test. Slight modifcation in the ridge lap surface of artifcial teeth alters the strength of the shear compressive bond. Sand papering of ridge lap surfaces improves the shear compressive bond then the one without any modifcation. Maximum shear compressive bond strength can be increased by application of monomer. PMID:24685795
Sadar, Leena; Dhume, Swaroop; Maniar, Neena; Prakash Patil, Jeevan; Rane, Prasad; Gandhewar, Mahesh
... 2012-04-01 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 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...
... 2011-04-01 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...
...2013-04-01 2013-04-01 false Preformed plastic denture tooth. 872.3590 Section...Prosthetic Devices Â§ 872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated...
...2012-04-01 false Preformed plastic denture tooth. 872.3590 Section 872.3590 Food...872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed...
...2010-04-01 false Preformed plastic denture tooth. 872.3590 Section 872.3590 Food...872.3590 Preformed plastic denture tooth. (a) Identification. A preformed plastic denture tooth is a prefabricated device, composed...
...2009-04-01 false Preformed gold denture tooth. 872.3580 Section 872.3580 Food...Devices Â§ 872.3580 Preformed gold denture tooth. (a) Identification. A preformed gold denture tooth is a device composed of austenitic...
...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...
...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...
...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...
One partially dentate person, his remaining teeth being 44, 43, 42, 41, 31, 32 and 33, was simultaneously provided with one maxillary complete denture and three mandibular free end saddle dentures having cobalt chromium alloy skeletons of different design. One denture was constructed with a lingual plate, another with a sublingual and a secondary bar, while on a third denture the major connector consisted of an enlarged secondary bar. On all the dentures occlusal rests were placed on teeth nos 44 and 33. Rosette strain gauges were placed in the midlines of all the major connectors. The gauges were calibrated on the master cast placed in a universal testing machine. The clinical recordings were taken from the gauges during one session under repeated loading conditions. Readings were repeated on one denture after removal of (1) the secondary bar and (2) the secondary bar and the occlusal rests. The recordings were used to calculate (1) the principal maximum and minimum strains and (2) the direction of the strains at the points of the bases beneath the centre of the gauges. The results show that studies of relevant functional deformation patterns of dentures can only be made in clinical experiments. Furthermore, they show that the base with an enlarged secondary bar exhibits more deformation than the other two types of base. Removal of the secondary bar did not significantly increase the deformation of the denture also equipped with a sublingual bar, neither did the removal of the occlusal rests. Both these changes, however, caused changes of the deformation patterns. PMID:7009809
Glantz, P O; Stafford, G D
The use of a silicone base under a total prosthesis makes possible the solution of certain problems of tolerance or maintenance of such denture. I.--Full denture in patients who have received radiotherapy. II.--Full denture with intolerant mucosa. III.--Following failure of classical prosthesis. IV--Prosthesis fitted following pre-prosthetic surgery. The technical problems associated with the fabrication of such prosthesis and possible adjustements are discussed. PMID:1058518
Cros, P; Achard, R; Brugirard, J
Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin
Z. Cao; X. Sun; C.-K. Yeh; Y. Sun
This is a 5-year retrospective survey of corneal infection in wearers of optical contact lenses (OCL). 23 of the 61 patients (38%; Hasharon Hospital) with positive cultures wore OCL. Visual acuity improved in 15 (65%), no change was noted in 4 (17.5%) and there was deterioration in 4 (17.5%), as compare with status on admission. Pseudomonas aeruginosa was the most common cause of infections among OCL wearers. The improvement in visual acuity expected due to wearing OCL was affected by infections. Those after Staphylococcus albus infections had the highest rate (100%) of improvement in visual acuity and after Ps. aeruginosa the lowest rate (57.2%) of improvement, as well as the highest rate of deterioration (42.8%) found following recovery. OCL wearers are at higher risk for damage to visual acuity following corneal infection, and highly virulent infections in OCL wearers are responsible for a high risk of damage to visual acuity. PMID:11062967
Domniz, Y; Avisar, R; Savir, H
Background: Candidiasis is common in denture wearers. Rough surfaces of dentures promote denture plaque formation and maturation, thus justifying the need for smooth surfaces. Proper finishing and polishing of dentures provide smooth surfaces. Thus, this study was done to assess the adherence of Candida to heat polymerized acrylic resin surfaces which were subjected to different stipulated polishing methods. Material and Methods: A total of 48 acrylic resin specimens of dimension 10x10x3 mm(3) were fabricated and divided into four groups, A, B,C and D, with 12 specimens in each group, according to method of polishing step which was employed. Subsequently, they were subjected to an adherence assay. All the data was statistically analyzed by using One-way ANOVA and differences within the groups were analyzed by using independent sample t-test. Results: Results revealed that group A which was unpolished had a mean adherence of 2.92 and it was finished by using sand papers. Group B had a mean adherence of 0.5 and it was finished by using sand papers, followed by polishing with pumice. Group C had a mean adherence of 2.92 and finishing was done by using sandpaper which was followed by polishing with the use of pumice and rouge. Group D had a mean adherence of 37.1667. Conclusion: Finishing specimens of heat cure denture base resin with sand paper of progressive grits alone exhibited minimum Candidal adherence. Specimens which were finished by using sand papers of progressive grits, followed by polishing with pumice reduced Candidal adherence marginally as compared to that in control group. Finishing specimens of heat cure denture base resin by using above steps, followed by rouge, showed maximum Candidal adherence. PMID:24298529
Satpathy, Ashish; M R, Dhakshaini; Gujjari, Anil Kumar
Background: Candidiasis is common in denture wearers. Rough surfaces of dentures promote denture plaque formation and maturation, thus justifying the need for smooth surfaces. Proper finishing and polishing of dentures provide smooth surfaces. Thus, this study was done to assess the adherence of Candida to heat polymerized acrylic resin surfaces which were subjected to different stipulated polishing methods. Material and Methods: A total of 48 acrylic resin specimens of dimension 10x10x3 mm3 were fabricated and divided into four groups, A, B,C and D, with 12 specimens in each group, according to method of polishing step which was employed. Subsequently, they were subjected to an adherence assay. All the data was statistically analyzed by using One-way ANOVA and differences within the groups were analyzed by using independent sample t-test. Results: Results revealed that group A which was unpolished had a mean adherence of 2.92 and it was finished by using sand papers. Group B had a mean adherence of 0.5 and it was finished by using sand papers, followed by polishing with pumice. Group C had a mean adherence of 2.92 and finishing was done by using sandpaper which was followed by polishing with the use of pumice and rouge. Group D had a mean adherence of 37.1667. Conclusion: Finishing specimens of heat cure denture base resin with sand paper of progressive grits alone exhibited minimum Candidal adherence. Specimens which were finished by using sand papers of progressive grits, followed by polishing with pumice reduced Candidal adherence marginally as compared to that in control group. Finishing specimens of heat cure denture base resin by using above steps, followed by rouge, showed maximum Candidal adherence.
Satpathy, Ashish; M.R., Dhakshaini; Gujjari, Anil Kumar
...homopolymer and/or carboxymethylcellulose sodium denture adhesive...homopolymer and/or carboxymethylcellulose sodium denture adhesive...homopolymer and/or carboxymethylcellulose sodium denture adhesive...
Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin discs were sustained for a prolonged period of time (weeks and months). Drug release was much faster at acidic conditions (pH 5) than at pH 7. Drugs bound to the denture materials could be “washed out” by treatment with EDTA, and the drug-depleted resins could be recharged with the same or a different class of anticandidal drugs. These results suggest clinical potential of the newly developed antifungal denture materials in the management of CADS and other infectious conditions.
Cao, Z.; Sun, X.; Yeh, C.-K.; Sun, Y.
Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin discs were sustained for a prolonged period of time (weeks and months). Drug release was much faster at acidic conditions (pH 5) than at pH 7. Drugs bound to the denture materials could be "washed out" by treatment with EDTA, and the drug-depleted resins could be recharged with the same or a different class of anticandidal drugs. These results suggest clinical potential of the newly developed antifungal denture materials in the management of CADS and other infectious conditions. PMID:20940361
Cao, Z; Sun, X; Yeh, C-K; Sun, Y
The aim of this investigation was to explore the relative importance of psychologic variables in explaining the degree of denture satisfaction in full denture patients. A group of 125 patients who were on a waiting list to have new dentures constructed participated in this study. The patients completed the Dutch version of the Hopkins Symptom Checklist, the Dutch Personality Inventory, a denture satisfaction questionnaire and a denture complaint questionnaire. No relation was found between the personality variables and denture satisfaction as measured by the denture satisfaction questionnaire. When the different aspects of denture satisfaction were measured by means of complaint scales, satisfaction was related to personality traits. Functional complaints of the mandibular denture and complaints about a hollow face were related to the personality trait "extraversion-introversion". Vague denture complaints and complaints about a bulbous face were related to "neuroticism". PMID:2019090
Vervoorn, J M; Duinkerke, A S; Luteijn, F; van de Poel, A C
Although clinician's skills and experience play a major role in designing and fabrication of the optimum prosthodontic restorations, the selection of denture resins is equally important, especially when the patient has been using the prostheses since long. Eighteen cases who were not satisfied with their conventional acrylic dentures were selected. They were provided flexible dentures along with a questionnaire to precisely evaluate the advantages of new material. Prosthodontic planning & observations regarding this material are discussed on various parameters.
Singh, J. P.; Dhiman, R. K.; Bedi, R. P. S.; Girish, S. H.
Objective To investigate the relationship between removable dentures and swallowing and describe risks. Methods Twenty-four patients with removable dentures who were referred for videofluoroscopic swallowing study (VFSS) were enrolled. We evaluated the change of swallowing function using VFSS before and after the removal of the removable denture. The masticatory performance by Kazunori's method, sensation of oral cavity by Christian's method, underlying disease, and National Institutes of Health Stroke Scale for level of consciousness were collected. Functional dysphagia scales, including the oral transit time (OTT), pharyngeal transit time (PTT), percentage of oral residue, percentage of pharyngeal residue, oropharyngeal swallow efficiency (OPSE), and presence of aspiration were measured. Results Four patients dropped out and 20 patients were analyzed (stroke, 13 patients; pneumonia, 3 patients; and others, 4 patients). The mean age was 73.3±11.4 years. There were significant differences before and after the removal of the denture for the OTT. OTT was significantly less after the removal of the denture (8.87 vs. 4.38 seconds, p=0.01). OPSE increased remarkably after the removal of the denture, but without significance (18.24%/sec vs. 25.26%/sec, p=0.05). The OTT and OPSE, while donning a removable denture, were correlated with the masticatory performance (OTT, p=0.04; OPSE, p=0.003) and sensation of oral cavity (OTT, p=0.006; OPSE, p=0.007). Conclusion A removable denture may have negative effects on swallowing, especially OTT and OPSE. These affects may be caused by impaired sensation of the oral cavity or masticatory performance induced by the removable denture.
Son, Dae-Sik; Seong, Jin Wan; Kim, Younghoon; Chee, Youngjoon
Patients with thin, nonresilient mucosa, poor ridge morphology, chronic xerostomia, and acquired or congenital defects are candidates for soft denture liners. Soft denture liners may be placed during fabrication of the new denture or during relining of the existing dentures. Soft mandibular denture liners are ideal for senior patients with resorbed mandibular ridges who need replacement of existing dentures to correct excessively closed vertical dimension of occlusion and for patients who have maxillary complete dentures and mandibular natural teeth, severe loss of maxillary ridge, and clenching habits. Soft denture liners should be used only when needed because of their short service life. However, for those patients who cannot tolerate hard denture bases, soft liners are an appropriate alternative treatment. PMID:8602422
Williamson, R T
Background: The high number of computer workers wearing contact lenses raises the question whether the sum of these two risk factors for eye health may cause a worsening of Computer Vision Syndrome. The aim of this review is to synthesize the knowledge about ocular and visual alterations related with computer use in contact lens wearers. Methods: International review of scientific papers (2003-2013) in Spanish and English, using Scoping Review method, in Medline through PubMed and in Scopus. Results: The initial search provided 114 references, after applying inclusion/exclusion criteria six of them were included. All of them reveal that symptoms when using computer are more prevalent in contact lens wearers, with values of symptoms presentation prevalence ranging from 95.0% to 16.9% in wearers and from 57.5% to 9.9% in non-wearers, and four times more likely to develop dry eye [OR: 4.07 (95% CI: 3.52 to 4.71)]. Conclusion: Computer workers suffer more ocular and visual disturbances if they also are contact lens users, but studies are few and non conclusive. Likewise, further research regarding contact lens type and their conditions of use, both in symptoms and tear quality and ocular surface are needed. Silicone hydrogel lenses are associated with more comfort. PMID:24914860
Tauste Francés, Ana; Ronda-Pérez, Elena; Seguí Crespo, María Del Mar
...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...
...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...
...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...
The materials and technologies for fabrication of denture bases have developed during the last 150 years. The requirements of the ideal material are versatile and include functional, physical and esthetical demands. The current manuscript classifies denture base materials according to their chemical characteristics into polymers, reinforced polymers and light cured polymers. Poly Methyl Metacrylate (PMMA) was developed 70 years ago, and is still the major material for fabrication of denture bases due to its esthetic characteristics, high processing and polishing abilities, relining and rebasing possibility and low cost. The main disadvantages of PMMA are its dimensional changes during polymerization, porosity and allergic/cytotoxic effects. PMMA may be reinforced by metal, polyethylene or glass fibers. Other materials used for fabrication of denture bases are Nylon and Urethane dimethacrylate. Their advantages are better esthetics, low modulus of elasticity and reduced cytotoxicity. This review presents the advances in materials and techniques used for denture bases, the different materials, their advantages and disadvantages, the chemical reactions associated with their production, and their allergic and cytotoxic side effects. PMID:22471154
Pietrokovski, Y; Pilo, R; Shmidt, A
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.
Gundawar, Sham; Zamad, Aakanksha; Gundawar, Sneha
Colonisation of denture soft lining materials by Candida albicans can result in clinical problems. The presence of Candida albicans on the upper fitting surface of the denture is a major causative factor in denture-associated chronic atrophic candidosis (denture stomatitis). The fitting surface of denture can act as a reservoir of Candida albicans. The goal of our experiment was to determine of candidal adherence to two soft lining materials -- Ufi gel C temporary and Ufi gel P permanent. Results of experiment show that adherence of Candida albicans to the Ufi gel C temporary was significantly move than for Ufi gel P permanent. PMID:15477833
Rostoka, D; Kro?cha, Iu; Kuznetsova, V; Re?nis, A; Tre?mane, R; Uikovskaia, T; Vanka, A
The main objective of a complete removable denture is to re-establish the function and aesthetics that lead to an acceptable soft tissue as well as psychologic integration. The fabrication of complete removable denture is a rather complex procedure being composed of several clinical and laboratory steps. All these steps are interdependant and governed by a certain level of empirism. The impression taking, the first part of the procedure, is crucial for the success of the whole prosthetic rehabilitation. The aim of this article is to describe in detail the impression taking procedures for complete removable dentures, in order to help solve a number of pitfalls encountered in daily clinical practice. PMID:16193854
Domken, O; Chichoyan, F; Prapotnich, R
In removable complete dentures, the occlusal vertical dimension is an important factor for patients' satisfaction with aesthetics. An excessively reduced occlusal vertical dimension is especially likely to lead to complaints about aesthetics, whereas an increased occlusal vertical dimension may lead to discomfort and a decision not to wear the complete dentures. There are various methods for determining the occlusal vertical dimension in complete dentures, based on the vertical dimension in the rest position of the mandible or on phonetics. However, none of the methods have proven to be clearly superior, in terms of reliability, than the others. The assessment of the occlusal vertical dimension will become more reliable if several methods are used simultaneously. Moreover, knowledge of the characteristics of the ageing face is essential. PMID:22292357
den Haan, R; Witter, D J
The author studied the problem of improving the quality of prosthetic removable prostheses through the development of new basic material based on polypropylene copolymer. To this end, we examined the physical and chemical structure and hygienic properties of the produced material. The studies found that the developed material of polypropylene optimal solution for the partial plate denture bases, without flaws acrylic prosthesis and improves the properties of the previously used polypropylene plastics. PMID:24214589
Shturminski?, V G
The goal of the study was to make a comparative assessment of the effect of the partial removable polypropylene and acrylic dentures on the prosthetic bed epithelium. The material of this study was smears-scrapes of the oral mucosa obtained from 316 patients. The results of the investigation of the morphological cell composition of the oral mucosa epithelium obtained from the prosthesis field and after prosthesis show a negative influence of the acrylic denture bases on the epithelium of the oral mucosa. The most optimal was the correlation of epithelial cells in the oral mucosa in the patients with dentures from "Tipplen R 359", processed in plasma of the glow discharge. PMID:24423673
Shuturminskiy, V; Chulack, L
Visual field testing of subjects wearing a niqab was carried out using the approved (Esterman) test on a Humphrey perimeter to determine if visually normal subjects met the European driving standard. Measurement of aperture dimensions of the niqab when worn was recorded. When wearing the niqab, all subjects achieved a visual field adequate to satisfy UK/European driving standards. A measurement of the limiting aperture size was obtained and a self-test method for niqab wearers was determined. PMID:18565085
Pearce, E Ian; Walsh, Glyn; Dutton, Gordon N
Abstract 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 their 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, recording the total numbers of colonies (cfu), their color, and their morphological characteristics. Significant differences were found in cfu values from the attachment and inner surfaces of locator- and bar-retained overdentures (P < 0.05). 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 > 0.05). PMID:23020624
Kilic, Kerem; Koc, Ayse Nedret; Tekinsen, Fatma Filiz; Yildiz, Pinar; Kilic, Duygu; Zararsiz, Gokmen; Kilic, Erdem
With an increase in the number of dependent elderly, there is a need to introduce few natural products for denture cleansing, which are easily and economically available. Hence the aim of this study was to compare the anticandidal efficacy of denture cleansing tablet (sodium bicarbonate and sodium perborate monohydrate), Triphala (Phyllanthus emblica, Terminalia chebula and Terminalia belerica fruits powders in equal proportion), cashew leaf, Aloe vera and water (control) on complete dentures of institutionalized elderly. Study population consisted of 50 institutionalized elderly of Mangalore, Karnataka, with 10 in each group. Swabs were collected from the dentures before and after the use of denture cleansing tablet, Triphala, cashew leaf, Aloe vera, and water (control). Thereafter, the swabs were cultured on Sabouraud dextrose agar and the total candida counts were determined. Denture cleansing tablet and Triphala Churna showed a statistically significant reduction in Candida counts (P < 0.05). Denture cleansing tablet and Triphala Churna were found to be more effective. PMID:24812470
Shetty, Pooja J; Hegde, Vijaya; Gomes, Leslie
With an increase in the number of dependent elderly, there is a need to introduce few natural products for denture cleansing, which are easily and economically available. Hence the aim of this study was to compare the anticandidal efficacy of denture cleansing tablet (sodium bicarbonate and sodium perborate monohydrate), Triphala (Phyllanthus emblica, Terminalia chebula and Terminalia belerica fruits powders in equal proportion), cashew leaf, Aloe vera and water (control) on complete dentures of institutionalized elderly. Study population consisted of 50 institutionalized elderly of Mangalore, Karnataka, with 10 in each group. Swabs were collected from the dentures before and after the use of denture cleansing tablet, Triphala, cashew leaf, Aloe vera, and water (control). Thereafter, the swabs were cultured on Sabouraud dextrose agar and the total candida counts were determined. Denture cleansing tablet and Triphala Churna showed a statistically significant reduction in Candida counts (P < 0.05). Denture cleansing tablet and Triphala Churna were found to be more effective.
Shetty, Pooja J.; Hegde, Vijaya; Gomes, Leslie
Aim of our paper is to present a case of painless Acanthamoeba keratitis in a soft contact lens wearer. A 17-year-old male, highly myopic, prolonged soft contact lens wearer, presented to us with painless red watery right eye having remarkably diminished vision. Last six weeks he was treated elsewhere for the microbial keratitis with no improvement. No pain was reported and on the direct questionnaire about it he denied it. There was marked mixed conjunctival and ciliary injection. A central stromal opacity with a pronounced surrounding corneal ring of inflammatory infiltration and epithelial defect was seen on biomicroscopy of the right eye. Circular pannus was already formed reaching epithelial defect overlying corneal ring infiltrate. Acanthamoeba spp in the corneal sample was confirmed. Prolonged therapy with 0.02% chlorhexidine digluconate solution combined with 0.1% hexamidine solution resulted in corneal healing left with a large central dense stromal opacity with circular pannus reaching peripheral third of the cornea but with very thin blood vessels and the best corrected visual acuity of 0.1 tested on Snellen chart. In conclusion, even in a lack of typical symptom for Acanthamoeba keratitis such as pain, this amoeba should be ruled out especially in a soft contact lens wearer. PMID:19860131
Elabjer, Biljana Kuzmanovi?; Busi?, Mladen; Sviben, Mario; Elabjer, Esmat; Predovi?, Jurica
...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...
...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...
...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 false Polyacrylamide polymer (modified cationic) denture adhesive...Devices § 872.3480 Polyacrylamide polymer (modified cationic) denture adhesive. (a) Identification. A polyacrylamide polymer (modified cationic) denture...
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.
Bahrani, Farideh; Khaledi, Amir Ali Reza
Severely atrophic ridges provide decreased retention, support, and stability and pose a clinical challenge to the success of complete denture prostheses. Extreme ridge resorption also increases the interridge distance. Restoration of the vertical dimension and esthetics thus demands increased height of the prosthesis and in turn leads to an increase in prosthesis weight. Reducing the weight of the denture enhances stability and retention and reduces further resorption of the jaw, thereby favoring the prognosis of the denture. This report describes the rehabilitation of an edentulous patient with resorbed maxillary and mandibular ridges and an increased interridge distance using simplified techniques of fabricating hollow dentures. PMID:22985439
Caculo, Shweta Pandurang; Aras, Meena Ajay; Chitre, Vidya
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
Multifocal lens glasses (MfLs) negatively affect vision, increase falling risk and contribute to gait changes during stepping. Previous studies on the effects of MfLs on gait have focused on experienced wearers. Thus, the initial response of first-time wearers, who may face significant challenges in adapting to these glasses, is not well understood. This study aimed to quantify the effects of MfLs on novice wearers during stepping up and down. Additionally, young adults were compared against a middle-aged adults to determine the validity of convenience sampling in testing novice response to MfLs. Fifteen young adults (18-34 y.o.) and seven middle-aged adults (46-56 y.o.) were recruited to perform stepping trials while wearing progressive MfLs and blank single lens glasses. Participants stepped up and down from a 75 mm and 150 mm step in randomized order. Step placement, minimum toe clearance, lower body kinematics and stepping time were measured during step up. Step placement, minimum heel clearance, vertical forces and stepping time were measured during step down. MfLs significantly increased toe clearance in the lead and trailing legs, hip flexion, knee flexion and stepping time during step up and increased vertical forces and stepping time during step down. Step placement and hip angle explained 17% of the toe clearance variability. Changes during step up suggest a more conservative adaptation while increased forces during step down suggest a reduced level of control. No age group effects were observed, which supports the use of convenience sampling for evaluating the novice response to MfLs. PMID:23770232
Beschorner, Kurt E; Milanowski, Autumn; Tomashek, Dennis; Smith, Roger O
One light-polymerized, three heat-polymerized, and three autopolymerized denture base polymers were exposed to coffee, tea, water at 50 degrees C +/- 1 degree C, as well as artificial sunlight and water, and evaluated for color stability. The color characteristics were determined using a computer-controlled spectrophotometer. Water sorption and solubility were assessed, and the materials were also chemically characterized. Coffee and tea stained the denture base materials superficially. Brushing with toothpaste and moderate grinding reduced discoloration to an acceptable level. All materials were relatively color stable when immersed in water at 50 degrees C +/- 1 degree C. The materials behaved differently when exposed to artificial sunlight and water. PMID:7993550
Buyukyilmaz, S; Ruyter, I E
The objective of this study was to characterize in vitro selected acrylic resin denture base materials by water-contact angle measurements. The sessile drop method and the underwater-bubble method were used. The results obtained from these measurements are discussed in terms of contact angle and polymer-water work of adhesion hysteresis. On polished heat-polymerized samples this hysteresis results from the reorientation of superficial polymer chains. The combined effect of increased sample roughness and of the entrapment of water droplets in the pores of material gives rise to the highest contact-angle hysteresis observed on sand-abraded samples. On the basis of physical analysis of the mechanism involved in complete denture retention, developed in Part I of this work, it is believed that the sand-abraded material is the most convenient for the retention of the complete denture. PMID:2681700
Monsénégo, P; Baszkin, A; Costa, M L; Lejoyeux, J
In order to chemically remove the calculus adhering to a denture, new denture cleaner was prepared on an experimental basis. The principal ingredient of this solution was a chilating agent which contained the phosphoric acid. This study consisted of the fundamental and the clinical examinations of this solution the purpose of which was to test the solvent power of this solution on the calculus and to evaluate its influence on the denture materials and its effectiveness in clinical practice. 1. the fundamental study 1) method (1) The test for the solvent power of this solution. The powder of tricalcium phosphate (T.C.P. powder: Wakohjunyaku Co.) was substituted for the calculus adhering to a denture. (1) The influence of the solution temperature on the solvent power. The T.C.P. powder was dissolved at 20 degrees C, 30 degrees C, 40 degrees C, 50 degrees C and 60 degrees C temperature in 10 g of the solution within 10 minutes and the amount of dissolved powder was weighted. The time was measured with a stop watch (Seiko Co.) until 0.5 g of T.C.P. powder had been dissolved in 10 g of the solution. (2) The effect of using it with an ultrasonic cleaner. The time to dissolve 0.1 g of T.C.P. powder in 10 g of this solution was compared with that of the 15% EDTA solution. The measurement was repeated 5 times and the arithmetic mean of the 5 sample values was calculated in order to show the experimental results. The room temperature was 19 +/- 2 degrees C, the humidity was 56 +/- 3%. (2) The influence of this solution on the denture materials. (1) resin specimen. In order to test the transverse strength, transverse deflection, Young's modulus and Knoop hardness, resin specimens were processed in the manner specified in I.S.O. 1567. The data were compared the resin specimens steeped in this solution and with the control sample that was steeped in water. The specimens were immersed up to 24 hours. Furthermore the existence of tarnish was observed with a 40 times microscope. (2) metal specimen. In order to test the corrosion, metal specimens were produced according to the manner of a corrosion test. The metal specimens were held vertically and the end immersed to 20 mm in this solution for 24 hours and 120 hours each. After steeping, each specimen was measured for loss in weight. The data were calculated as the loss in weight per hour (mg/cm) and the depth of corrosion per year (mm/yr).(ABSTRACT TRUNCATED AT 400 WORDS) PMID:2486722
Ishikawa, C; Hosoi, T; Morito, M; Miwa, E; Tsuchida, F; Ohtsuki, M; Hirono, I; Sawada, O
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.
Farzin, M; Bahrani, F; Adelpour, E
The porosity of denture base resins continues to be one of the undesirable characteristics of acrylic resins. It is commonly accepted that porosity of the denture not only often leads to denture fractures, but also may function as a reservoir of potential pathogens. The purpose of this study was to present the first OCT images of finished dentures using a
Yasunori Sumi; Nobuyoshi Ozawa; Shuichiro Nagaosa; Shunsuke Minakuchi; Osami Umemura
Characterization of an artificial denture is required to give the denture a more natural appearance. This article describes the laboratory procedures for internal characterization of denture base in a removable prosthesis using acrylic stains and absorbent tissue paper incorporated in the heat cure polymerizing denture base resin at the stage of packing. PMID:22942582
Pattanaik, Seema; Pattanaik, Bikash
Acrylic resin denture teeth often exhibit rapid occlusal wear, which may lead to a loss of chewing efficiency and a loss of vertical dimension of occlusion. The use of metal occlusal surfaces on the acrylic resin denture teeth will minimize occlusal wear. Several articles have described methods to construct metal occlusal surfaces; however, these methods are time-consuming, costly, and sometimes
Carlos Eduardo Vergani; Eunice Teresinha Giampaolo; Ana Lucia Machado Cucci
This paper describes a previously unknown denture constructed from hippopotamus ivory. The denture is unusual in that it is anatomically correct in terms of tooth morphology. It is believed that it was a demonstration item for the Great Exhibition of 1851. PMID:24620435
This study categorizes older adults living in rural areas by denture status, assesses the frequency of wearing dentures during meals, and determines whether denture status or use is associated with dietary quality or the number of foods avoided. A multi-ethnic population-based sample of adults ?60 years (N = 635) in the rural United States was interviewed. Survey included denture use, removing dentures
Margaret R. Savoca; Thomas A. Arcury; Xiaoyan Leng; Haiying Chen; Ronny A. Bell; Andrea M. Anderson; Teresa Kohrman; Gregg H. Gilbert; Sara A. Quandt
Data sourcesThe Cochrane database of systematic reviews, the Cochrane Central Register of Controlled Trials (CENTRAL), Medline and Embase databases and reference lists of identified articles were searched with no language restriction.Study selectionRandomised controlled trials that compared the efficacy of antifungal medications with other treatments of denture-related erythematous stomatitis in adults wearing conventional acrylic removable complete dentures were included. Trials of seven days or fewer were excluded.Data extraction and synthesisStudy assessment and data extraction were carried out independently by at least two reviewers. Study quality was assessed using Cochrane methodology. Odds Ratios (OR) and 95% Confidence Interval (CI) were calculated to compare results across studies using a random effects model.ResultsFourteen randomised controlled trials were included in the review, with eight studies contributing to the meta-analysis. No statistically significant difference between antifungal treatment and disinfection methods was found for both clinical and microbiological outcomes. Meta-analysis showed a statistically significant difference between an antifungal and a placebo for the microbiological outcome (OR=0.32; 95% CI: 0.12-0.89; Z=-2.2; p=0.028), favouring the antifungals. There was no statistically significant difference between antifungal and placebo for the clinical outcome (OR=0.2; 95% CI: 0.04-1.04; Z=-1.9; p=0.056).ConclusionsThe findings of this review and meta-analysis suggest that disinfection methods could be considered as an adjunct or alternative to antifungal medications in the treatment of denture stomatitis. PMID:24971864
Lalla, Rajesh V; Dongari-Bagtzoglou, Anna
(Full text is available at http://www.manu.edu.mk/prilozi). While utilizing removable dentures, regardless of whether the dentures are acrylic or fabricated of eclipse resin, the need for their filling-relining or their repair frequently arises. The purpose of this study is to display the technicalities of the procedure for rebasing and relining of removable light curing eclipse denture resin. Material and methods: This study presents cases of relining and repairing of removable dentures fabricated from light curing ECLIPSE resin on patients at the Department for Removable Prosthodontics at the University Dental Clinic Centre in Skopje. Conclusion: One of the most significant features of this method of fabrication of removable eclipse dentures and their relining and repairing is the shortened duration of work in the dental laboratory. The displayed mode of rebasing also allows us to maintain one of the advantages of this type of dentures - the absence of allergy stomatitis symptoms. Key words: Removable dentures, repairing, relining, light polymeric eclipse resin. PMID:24802203
Bundevska, J; Panchevska, S; Kovacevska, G
Colonization of denture lining materials by microorganisms including Candida albicans can result in deterioration of the material, as observed by a previous in vitro study by the authors. The current in vivo study monitored the microbial colonisation and penetration of five types of denture liners and their topography over six months. There was no significant difference in the microbial colonisation on the denture liners and no penetration observed, indicating a slower rate of deterioration of materials in vivo. However the surface roughness of all materials increased during use, which might alter susceptibility to subsequent microbial colonisation. PMID:18637378
Taylor, Rebecca L; Bulad, Khaled; Verran, Joanna; McCord, J Fraser
This study categorizes older adults living in rural areas by denture status, assesses the frequency of wearing dentures during meals, and determines whether denture status or use is associated with dietary quality or the number of foods avoided. A multi-ethnic population-based sample of adults ?60 years (N=635) in the rural US was interviewed. Survey included denture use, removing dentures before eating, and foods avoided due to oral health problems. Dietary intakes were converted into Healthy Eating Index-2005 scores. Sixty percent wore removable dentures of some type; 55% never, 27% sometimes, and 18% always removed dentures when eating. More frequent removal was associated with lower dietary quality and more foods avoided. Those with severe tooth loss had the lowest dietary quality and avoided the most foods. Many rural older adults wear dentures. Learning how they adapt to denture use will offer insight into their nutritional self-management and help explain differences in dietary quality.
Savoca, Margaret R.; Arcury, Thomas A.; Leng, Xiaoyan; Chen, Haiying; Bell, Ronny A.; Anderson, Andrea M.; Kohrman, Teresa; Gilbert, Gregg H.; Quandt, Sara A.
Six thermoplastic resins and conventional acrylic resin were examined to characterize their mechanical and physical properties, water sorption, solubility, flexural strength, modulus of elasticity, tensile strength and color stability. Thermoplastic resins for non-metal clasp dentures exhibiting low water sorption and solubility offer hygienic advantages. Since they have a low modulus of elasticity and are easily manipulated, these materials make it possible for larger undercuts to be used for retention compared to acrylic resin. Not all of the thermoplastic resins tested fractured after the bending test in contrast to the conventional denture base resin, which fractured when tested beyond its proportional limit. It was also found that clinically noticeable staining may occur on the polyamide resins and polyethylene terephtalate resins. PMID:20644329
1. There was a high incidence of the personality traits of hypochondriasis, depression, hysteria, and manifest anxiety in the 70 complete denture patients of this study. 2. Most patients in this study were satisfied with the complete dentures received. 3. There was no significant relationship between the personality traits of hypochondriasis, depression, hysteria, and manifest anxiety and the degree of patient satisfaction with dentures. 4. There was no significant relationship between the personality traits of hypochondriasis, depression, hysteria, and manifest anxiety and the techinical quality of dentures. 5. There was no significant relationship between the technical quality of complete dentures and the degree of patient satisfaction with the same dentures. PMID:775057
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
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
A 68 years edentulous female, wearing unsuccessful complete dentures, was treated by making a new set of dentures. The main initial complains were unaesthetic teeth, excessive gums display, speech impairment and severe difficulties in mastication. With the patient's full collaboration and following sound established prosthodontics principles, a successful set of full dentures was provided. The main changes performed with the new set of dentures were: A. Provision of three millimeters interocclusal rest space between the vertical dimension while in occlusion and the vertical dimension of rest. B. The full anterior and premolars maxillary teeth and the incisal's third of the mandibular anterior teeth were displayed when patient was speaking, smiling and laughing. No artificial gums were displayed during any normal facial or oral activities. C. The occlusal plane was established after the selection of the anterior teeth. The plane was made parallel to the ala tragus (Camper's) line. PMID:20162988
Zini, A; Pietrokovski, Y; Pietrokovski, J
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.
Hereditary ectodermal dysplasia is a rare group of inherited disorders characterized by aplasia or dysplasia of two or more tissues of ectodermal origin such as hair, nails, teeth, and skin. The dental characteristics of this syndrome include anodontia or hypodontia of the primary and/or permanent teeth, hypoplastic conical teeth, and underdevelopment of the alveolar ridges. The options for a definitive treatment plan include fixed, removable or implant-supported prostheses, singly or in combination. This clinical report describes the prosthetic rehabilitation of an 11-year-old boy with hereditary ectodermal dysplasia. Maxillary flexible removable partial denture and mandibular conventional complete denture were fabricated to establish an acceptable masticatory function, speech, and esthetics for the patient.
Jain, Neha; Naitam, Dinesh; Wadkar, Arti; Nemane, Anuradha; Katoch, Shiva; Dewangan, Ashish
Nylon denture base material could be a useful alternative to poly (methyl methacrylate) (PMMA) in special circumstances such as patient allergy to the monomer. The aim of this study was to evaluate the flexural properties of a nylon denture base material (Lucitone FRS), a conventional compression-moulded heat-polymerized (Meliodent), a compression-moulded microwave-polymerized (Acron MC) and an injection-moulded microwave-polymerized (Lucitone 199) PMMA
N. Yunus; A. A. Rashid; L. L. Azmi; M. I. Abu-Hassan
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.
Bugurman, Bugurman Burcu
This article describes a method of converting an interim maxillary removable complete denture to an interim implant-supported fixed complete denture. The advantages of this method are that it provides the opportunity to evaluate the patient's function and esthetics, and helps the accurate transfer of the maxillomandibular relationship to the laboratory. Consequently, the fabrication of the definitive prostheses is accurate, and the final result is predictable. PMID:21438961
Michalakis, Konstantinos X; Touloumi, Foteini; Calvani, Lino; Bedi, Abheyjit; Hirayama, Hiroshi
A test rig has been designed for transverse bend testing on the Instron machine. The rig is a robust, accurately machined piece of equipment that enables this test to be carried out with accuracy and ease. A range of denture base polymers has been tested under similar conditions to the ISO standard recommendations (ISO/R 1567, 1974), and in this series all the materials except 3 satisfied the criteria laid down in the standard. The specimens were tested in water after 1 month because it has been shown previously that the materials are almost fully saturated at that time (Stafford and Huggett, 1973). Nevertheless, this immersion in water may also weaken the material and this could account for the failure of some materials to pass the standards criteria. PMID:1059644
Stafford, G D; Handley, R W
Dentures made of 2 different types of injection-molded thermoplastic resins (polyamide resin and polyester resin) and a denture made of conventional heat-polymerized resin were used to create an experimental model of a mandibular molar region with a two-tooth gap. In the experimental model, a force of 100 N was applied onto the mesial fossa of the first molars of the dentures, and comparisons were performed by measuring the pressure applied under the denture base and the subsidence rate of the denture. The polyamide resin denture showed the highest subsidence, exerted the highest pressure on the underlying mucosa, and showed significant differences with the other types of dentures. The findings showed that polyamide resins have the lowest degree of elasticity, and that when resins with such low elasticities are used in the denture base, they should preferably be reinforced with metals. PMID:23719015
Wadachi, Juro; Sato, Masayuki; Igarashi, Yoshimasa
Denture cleansers are frequently found in the American household since there are in excess of 16 million people wearing dentures. These ubiquitous products were thought to be without serious complications, but this belief was recently changed when a dentu...
A. L. Abramson R. L. Eason W. H. Pryor E. J. Messer
Statement of problem. Previous studies have investigated possible associations between the accuracy of intermaxillary relations and complete denture usage with variable results. Purpose. This study investigated the association between the intermaxillary relations in new complete dentures and the use of these dentures for daily wear and eating. Methods. A prospective study of patients (n = 523) attending Guy’s Dental Hospital
Michael R. Fenlon; Martyn Sherriff; John D. Walter
Objectives Candida-associated denture stomatitis is a recurrent and debilitating oral mucosal disease. Development of anticandidal denture materials represents a promising strategy to manage this condition. We have previously shown that miconazole incorporated in methacrylic acid (MAA) copolymerized diurethane dimethacrylate (UDMA) denture materials has long-term anticandidal activity. In this study, we examined the ability of culture medium conditioned with drug-free- or miconazole-MAA-UDMA discs to prevent Candida infection in an in vitro oral epithelial cell/Candida albicans co-culture system. Material and Methods Candida albicans (C. albicans) induced OKF6/TERT-2 cell damage was quantified by the release of lactate dehydrogenase from epithelial cells, cytokine production was quantified using protein cytokine arrays, and the expression of C. albicans genes was measured by RT-qPCR. Results C. albicans had limited growth with altered expression levels of secreted aspartyl proteinase-2 and -5 in culture medium conditioned by miconazole-MAA-UDMA discs. Significantly, the ability of C. albicans to induce oral epithelial cell damage and trigger epithelial proinflammatory cytokine production was also inhibited by miconazole disc conditioned media. Conclusion Miconazole released from MAA-UDMA denture materials effectively prevents the development of candidal infection in an in vitro oral epithelial system. Further characterization of this drug-rechargeable denture material is warranted.
Villar, Cristina C.; Lin, Alan L.; Cao, Zhengbing; Zhao, Xiang-Ru; Wu, Li-An; Chen, Shuo; Sun, Yuyu; Yeh, Chih-Ko
When multiple anterior teeth are missing, many options of replacement are available. Traditionally, the choice was between a fixed or removable prostheses. Today, with the predictability of dental implants, the options of tooth replacement range from removable partial dentures to implant-supported fixed prostheses. The choice of which restoration that will best provide occlusion and esthetics depends on multiple factors including the number and location of missing teeth, the residual ridge form in relation to the replacement teeth, the relationship of the maxillary and mandibular anterior teeth, the condition of teeth adjacent to the edentulous span, the amount of bone available for implant placement, the patients "smile line" and display of teeth, lip support, and financial constraints. When there is minimal loss of the ridge contour, restorations that emerge from the ridge are the most functional and esthetic restorations, adhesive-type fixed partial dentures, conventional fixed partial dentures, and implant-supported restorations can be indicated with the choice of restoration dependent on a risk benefit and cost benefit analysis. When there is a loss of ridge contour due to residual ridge resorption or trauma, the decision becomes more complex as not only does the tooth structure need to be replaced, the ridge form also has to be replaced. (Figures 1 and 2). This can be assessed clinically as illustrated by Figures 1 and 2 where a dis crepancy in arch form and ridge form in relation to the adjacent teeth and/or opposing arch can be observed. Other considerations are lip support and display of the teeth when smiling. This article presents a case and rationale for implant-supported par tial overdentures. Many authors have written on the merits of com plete overdentures. The complete overdenture has proven to be an improvement over conventional complete prostheses with respect to chewing efficiency, patient comfort and satisfaction. In partial edentulism, the implant-supported overdenture has several advantages, some in common with a removable partial denture. PMID:15915882
Chee, Winston W L
Fungal keratitis represents one of the most difficult forms of microbial keratitis to diagnose and treat successfully. It is difficult to obtain correct diagnosis and topical antifungal preparations. Fungi can cause severe stromal necrosis and enter the anterior chamber by penetrating an intact Descemet membrane. The most common pathogens are filamentous fungi (Aspergillus and Fusarium spp.) and Candida albicans. The incidence of Trichophyton spp. keratitis is 5%. A 22 years old female contact lenses wearer after keratitis developed corneal melting syndrome, spontaneous perforation of the cornea and complicated cataract of the left eye. Conjunctival swab was sterile as well as first sample of corneal tissue and sample from the anterior chamber. Urgent therapeutic perforating keratoplasty (PK), was performed together with extracapsular cataract extraction and the implantation of the intraocular lens in the posterior chamber. The patient was treated with ciprofloxacin and diflucan (systemic therapy); with dexamethason and atropin (subconjunctivaly) and chlorhexidine, brolene, levofloxacin, polimyxin B, and dexamethason/neomycin (topically). Microbiology evaluation was performed once again following excisional biopsy of the intracameral portion of the lesion. The presence of Trichophyton spp. was finally confirmed. Itraconazole and garamycin were included in the systemic therapy. Corneal graft was clear for 17 days but decompensated 28 days after the PK. After two weeks microorganisms invaded the vitreous and caused endophthalmitis. Despite urgent pars plana vitrectomy patient developed endophthalmitis, lost light sensation and developed phthysis. Evisceration and the implantation of silicon prosthesis was done. Perforating keratoplasty is a method of choice in treating severe infectious keratitis unresponsive to conservative treatment but without the eradication of microorganisms it cannot restore the vision or save the eye. Trichophyton spp. may cause a severe disease of the anterior and posterior part of the eye which may finish with the lost of vision/eye. Prompt diagnosis and treatment of Trichophyton spp. keratitis are essential for a good visual outcome. PMID:21302731
Mravici?, Ivana; Dekaris, Iva; Gabri?, Nikica; Romac, Ivana; Glavota, Vlade; Sviben, Mario
Purpose. We characterized electrically elicited visual evoked potentials (eVEPs) in Argus II retinal implant wearers. Methods. eVEPs were recorded in four subjects, and analyzed by determining amplitude and latency of the first two positive peaks (P1 and P2). Subjects provided subjective feedback by rating the brightness and size of the phosphenes. We established eVEP input–output relationships, eVEP variability between and within subjects, the effect of stimulating different areas of the retina, and the maximal pulse rate to record eVEPs reliably. Results. eVEP waveforms had low signal-to-noise ratios, requiring long recording times and substantial signal processing. Waveforms varied between subjects, but showed good reproducibility and consistent parameter dependence within subjects. P2 amplitude overall was the most robust outcome measure and proved an accurate indicator of subjective threshold. Peak latencies showed small within-subject variability, yet their correlation with stimulus level and subjective rating were more variable than that of peak amplitudes. Pulse rates of up to 2/3 Hz resulted in reliable eVEP recordings. Perceived phosphene brightness declined over time, as reflected in P1 amplitude, but not in P2 amplitude or peak latencies. Stimulating-electrode location significantly affected P1 and P2 amplitude and latency, but not subjective percepts. Conclusions. While recording times and signal processing are more demanding than for standard visually evoked potential (VEP) recordings, the eVEP has proven to be a reliable tool to verify retinal implant functionality. eVEPs correlated with various stimulus parameters and with perceptual ratings. In view of these findings, eVEPs may become an important tool in functional investigations of retinal prostheses. (ClinicalTrials.gov number NCT00407602.) Dutch Abstract
Stronks, H. Christiaan; Barry, Michael P.; Dagnelie, Gislin
Bar and clip attachments significantly improve the level of satisfaction of denture-wearing patients by enhancing the retention and stability of the prosthesis. These attachments have been most commonly used for connecting the prosthesis to implants, but they can be effectively used to retain tooth-supported prosthesis as well. The primary functions of bar attachments are splinting the abutments together, even distribution of forces to the abutments and supporting areas, guiding the prosthesis into place, improving the retention, stability, support and comfort of the patient. The primary requirement for the use of bar attachments is the availability of sufficient vertical and buccolingual space for the proper placement of the bar, sleeves, teeth arrangement and sufficient thickness of acrylic denture base to minimise incidence of denture fracture in the area of bar assembly. PMID:24145505
Singh, Kunwarjeet; Gupta, Nidhi; Kapoor, Vikram; Gupta, Ridhimaa
Conventional manufacturing of individual ceramic dental prosthesis implies a handmade metallic framework, which is then veneered with ceramic layers. In order to manufacture all-ceramic dental prosthesis a CAD/CAM system is necessary due to the three dimensional shaping of high strength ceramics. Most CAD/CAM systems presently grind blocks of ceramic after the construction process in order to create the prosthesis. Using high-strength ceramics, such as Hot Isostatic Pressed (HIP)-zirconia, this is limited to copings. Anatomically shaped fixed dentures have a sculptured surface with small details, which can't be created by existing grinding tools. This procedure is also time consuming and subject to significant loss in mechanical strength and thus reduced survival rate once inserted. Ultra-short laser pulses offer a possibility in machining highly complex sculptured surfaces out of high-strength ceramic with negligible damage to the surface and bulk of the ceramic. In order to determine efficiency, quality and damage, several laser ablation parameters such as pulse duration, pulse energy and ablation strategies were studied. The maximum ablation rate was found using 400 fs at high pulse energies. High pulse energies such as 200?J were used with low damage in mechanical strength compared to grinding. Due to the limitation of available laser systems in pulse repetition rates and power, the use of special ablation strategies provide a possibility to manufacture fully ceramic dental prosthesis efficiently.
Werelius, Kristian; Weigl, Paul
Over the years various methods of denture marking have been reported in the literature. They include surface marking and inclusion techniques using metallic or non-metallic materials, microchips and microlabels. The microchips are preferred because of their small size and aesthetic acceptability. They are not however widely used due to the high cost of manufacture and data incorporation. This article details the procedures involved in inscribing a microchip using the photochemical etching process used in the electronics industry. The resulting microchip was cosmetically appealing, cost effective and was able to satisfy all the forensic requirements for a suitable denture marker. PMID:12085521
Rajan, M; Julian, R
Conventional complete denture prosthetics require several appointments to register the maxillomandibular relationship and evaluate the esthetics. The fabrication of milled complete dental prostheses with digital scanning technology may decrease the number of appointments. The step-by-step method necessary to obtain impressions, maxillomandibular relation records, and anterior tooth position with an anatomic measuring device is described. The technique allows the generation of a virtual denture, which is milled to exact specifications without the use of conventional stone casts, flasking, or processing techniques. PMID:24461946
Infante, Luis; Yilmaz, Burak; McGlumphy, Edwin; Finger, Israel
Objective To determine whether the provision of single lens distance glasses to older wearers of multifocal glasses reduces falls. Design Parallel randomised controlled trial stratified by recruitment site and source of referral, with 13 months’ follow-up and outcome assessors blinded to group allocation. Setting Community recruitment and treatment room assessments in Sydney and Illawarra regions of NSW, Australia. Participants 606 regular wearers of multifocal glasses (mean age 80 (SD 7) years). Inclusion criteria included increased risk of falls (fall in previous year or timed up and go test >15 seconds) and outdoor use of multifocal glasses at least three times a week. Interventions Provision of single lens distance glasses with recommendations for wearing them for walking and outdoor activities compared with usual care. Main outcome measures Number of falls and injuries resulting from falls during follow-up. Results Single lens glasses were provided to 275 (90%) of the 305 intervention group participants within two months; 162 (54%) of the intervention group reported satisfactory use of distance glasses for walking and outdoor activities for at least 7/12 months after dispensing. In the 299 intervention and 298 control participants available to follow-up, the intervention resulted in an 8% reduction in falls (incidence rate ratio 0.92, 95% confidence interval 0.73 to 1.16). Pre-planned sub-group analyses showed that the intervention was effective in significantly reducing all falls (incidence rate ratio 0.60, 0.42 to 0.87), outside falls, and injurious falls in people who regularly took part in outside activities. A significant increase in outside falls occurred in people in the intervention group who took part in little outside activity. Conclusions With appropriate counselling, provision of single lens glasses for older wearers of multifocal glasses who take part in regular outdoor activities is an effective falls prevention strategy. The intervention may be harmful, however, in multifocal glasses wearers with low levels of outdoor activity. Trial registration Clinical trials NCT00350855.
Oral inflammation, such as periodontitis, can lead to endothelial dysfunction, accelerated atherosclerosis, and vascular dysfunction. The relationship between vascular dysfunction and other common forms of oral infections such as denture-related stomatitis (DRS) is unknown. Similar risk factors predispose to both conditions including smoking, diabetes, age, and obesity. Accordingly, we aimed to investigate endothelial function and major vascular disease risk factors in 44 consecutive patients with dentures with clinical and microbiological features of DRS (n = 20) and without DRS (n = 24). While there was a tendency for higher occurrence of diabetes and smoking, groups did not differ significantly in respect to major vascular disease risk factors. Groups did not differ in main ambulatory blood pressure, total cholesterol, or even CRP. Importantly, flow mediated dilatation (FMD) was significantly lower in DRS than in non-DRS subjects, while nitroglycerin induced vasorelaxation (NMD) or intima-media thickness (IMT) was similar. Interestingly, while triglyceride levels were normal in both groups, they were higher in DRS subjects, although they did not correlate with either FMD or NMD. Conclusions. Denture related stomatitis is associated with endothelial dysfunction in elderly patients with dentures. This is in part related to the fact that diabetes and smoking increase risk of both DRS and cardiovascular disease.
Osmenda, Grzegorz; Nowakowski, Daniel; Wilk, Grzegorz; Maciag, Anna; Mikolajczyk, Tomasz; Sagan, Agnieszka; Filip, Magdalena; Drozdz, Miroslaw; Guzik, Tomasz J.
The porosity of denture base resins continues to be one of the undesirable characteristics of acrylic resins. It is commonly accepted that porosity of the denture not only often leads to denture fractures, but also may function as a reservoir of potential pathogens. The purpose of this study was to present the first OCT images of finished dentures using a new advanced-type OCT scanner we have developed, and to discuss the application of our new OCT system for nondestructive inspection of dentures. Ten newly fabricated full dentures of outpatient of the National Center for Geriatrics and Gerontology in Japan were selected for this study. Two types of denture base resins were used for inspection by OCT, which provided clear images of all the dentures examined. Internal structures, not visually detectable, inspection, can be observed using this OCT system. It is concluded that OCT can detect nonvisible internal structures in dentures, a finding not reported to date. OCT may, therefore, be an appropriate method for detecting interior defects in dentures nondestructively. PMID:21163538
Sumi, Yasunori; Ozawa, Nobuyoshi; Nagaosa, Shuichiro; Minakuchi, Shunsuke; Umemura, Osami
Complete denture services at comprehensive care public health clinics are not common in part because of clinician concerns regarding outcomes. Educational debt forgiveness has attracted recent dental graduates to public health dentistry; however, not all recent graduates receive denture education experiences necessary to attain proficiency. While fundamental patient assessment and denture construction are taught, psychological assessment and communication with denture patients requires experience. A thorough understanding of occlusion, phonetics, esthetics and laboratory steps is also necessary. Expecting recent dental graduates to become proficient providing complete dentures at minimal reimbursement levels, with no mentorship or on-site laboratory support, is unrealistic. Public health dental clinics operate at full capacity performing emergency, preventive and restorative procedures. Complete dentures come with a laboratory fee approximately one-half the total reimbursement, meaning a remake drops clinic revenue to zero while doubling expenses. It is understandable that full schedules, marginal reimbursement, unpredictability and the risk of an occasional failure block clinician interest in providing denture services. This one-year report of services describes a three-appointment complete denture technique offering improved patient and laboratory communication, reduced chair time and controlled cost, resulting in high-quality complete dentures. PMID:22013657
In the absence of any clearly identifiable pathologic condition, the prosthodontic patient demonstrating speech problems after insertion of complete dentures is having difficulty with loss of turbulence, because of the diminution of tactile location skills in speaking, or both. Potential aids to speech improvement are a nonanatomic papilla placed on the oral surface of the denture just posterior to the location of the incisive papilla, a transversely elongated rugae-like papilla at about the same location, a roughened region at that spot, or an identation sufficient for the patient's tongue to identify. The location and effectiveness of such structural changes can be planned and judged with the cooperation of a qualified speech pathologist. PMID:374711
Palmer, J M
This study aimed to investigate the shear bond strength of an autopolymerizing resin to a nylon denture base polymer (Lucitone FRS: LT) subjected to different surface treatments, and the results thereof compared with a heat-polymerizing resin and a polycarbonate polymer. Specimens were divided into five groups according to the surface treatment method: polishing (#600), sandblasting, adhesive primer application (resin primer), sandblasting + adhesive primer application, and tribochemical coating (Rocatec system). Following which, specimens were subjected to a shear bond strength test and Si concentrations were measured using an electron probe microanalyzer (EPMA). On shear bond strength, that of LT with tribochemical coating was significantly higher than the other groups. On EPMA results, the surface of LT with tribochemical coating was found to be covered with a silica film. Therefore, findings in this study indicated that silica-coating by Rocatec system was effective in improving the bond strength of nylon denture base polymer to autopolymerizing repair resin. PMID:19721277
Katsumata, Yuki; Hojo, Satoru; Hamano, Naho; Watanabe, Tomonaga; Yamaguchi, Hiroaki; Okada, Shusaku; Teranaka, Toshio; Ino, Satoshi
The aim of the present study was to measure various mechanical properties of acrylic denture base resins, including flexural modulus, flexural strength, fracture toughness, Barcol and Vickers hardness and their related properties, and to investigate correlations between different mechanical properties. Resin specimens were prepared according to manufacturers' recommended instructions. The mechanical properties were measured under specified standards. Data from the mechanical tests were examined using correlation tests. In general, the mean results for mechanical properties of each specimen group were differently ranked depending on the tested mechanical property. The flexural modulus value showed strong or reasonable positive correlation with those of proportional limit, flexural strength, and surface hardness. In contrast, fracture toughness revealed strong negative correlations with the flexural parameters and hardness values. Results of correlation tests for the different parameters can be used for estimation of mechanical performance of acrylic denture bases in clinical situation and for quality control purposes. PMID:22277620
Lee, Hae-Hyoung; Lee, Chung-Jae; Asaoka, Kenzo
The psychological status of a geriatric patient undergoing complete denture treatment is one of the key determinants of the success of prosthesis. Hence, the understanding and behavior management of such patients is of paramount importance for any clinician aspiring to be a successful in practice. Even though several attempts have been made to understand the effects of psychology of patients undergoing this particular treatment on the final outcome of treatment, no single theory or classification has been proposed so far as to be able to completely understand the thought process of geriatric patients. The aim of this paper is to propose a theoretical approach, a step by step guide to clinicians to better understand the thoughts, aspirations and expectations of complete denture patients and their effects and consequences in different patients, when not met with. PMID:22665758
Sudheer, A; Reddy, G Vivekananda; Reddy, Giridhar
A replica of an atrophied mandible was constructed in which two Brånemark implants were embedded to simulate osseointegration. Ferromagnetic keepers were then attached to the implants. A complete overdenture was constructed which had magnets positioned directly over the keepers. The denture was then subjected to different loads and the stresses were photographically recorded. The denture was also tested for its retention capabilities. Because of the equitable stress distribution with the absence of high foci of concentration, a magnetically-retained overdenture with osseointegrated supports lends itself well as a prosthetic replacement. In addition, the magnets exhibit sufficient retention without unduly loading the implants or residual ridge. It may be concluded that in a similar in vivo situation, magnets could be an alternative to other attachment systems; however, there are many variables to be considered on an individual patient basis. PMID:3054071
Highton, R; Caputo, A A; Kinni, M; Matyas, J
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
PURPOSE To compare the effect of sodium hypochlorite and microwave disinfection on the dimensional stability of denture bases without and with relining. MATERIALS AND METHODS A brass die was prepared by simulating an edentulous maxillary arch. It was used to fabricate 1.5 mm and 3 mm of thickness denture bases (n = 40). The 1.5 mm of thickness-specimens (n = 20) were relined with 1.5 mm of autopolymerizing relining resin. Five holes were prepared over crest of ridge of brass die with intimately fitting stainless steel pins which were transferred to the intaglio surface of specimens during fabrication of denture bases. For calculation of dimensional changes in denture bases, differences between the baseline area before and after disinfection of the specimens were used. The denture bases without and with relining were divided into 2 groups (each n = 20). Data were analyzed using student paired 't' and unpaired 't' test. RESULTS Microwave disinfection produces significant shrinkage in both denture bases without relining (t = 17.16; P<.001) and with relining (t = 14.9; P<.001). Denture bases without relining showed more shrinkage when compared with relined denture bases after microwave disinfection (t = 6.09; P<.001). The changes in dimensional stability after sodium hypochlorite disinfection were not significant for both denture bases without relining (t = 2.19; P=.056) and denture bases with relining (t = 2.17; P=.058). CONCLUSION Microwave disinfection leads to increased shrinkage of denture bases without and with relining. Chemical disinfection with sodium hypochlorite seems to be a safer method of disinfection with regards to physical properties such as changes in dimensional stability.
Thombre, Ram; Kubasad, Girish
Nylon denture base material could be a useful alternative to poly (methyl methacrylate) (PMMA) in special circumstances such as patient allergy to the monomer. The aim of this study was to evaluate the flexural properties of a nylon denture base material (Lucitone FRS), a conventional compression-moulded heat-polymerized (Meliodent), a compression-moulded microwave-polymerized (Acron MC) and an injection-moulded microwave-polymerized (Lucitone 199) PMMA polymers. The effect of aldehyde-free, oxygen releasing disinfectant solution (Perform) on these properties was also investigated. The flexural modulus and the flexural strength were assessed with a three-point bending test. Specimens were stored in water at a temperature of 37 degrees C for 30 days. For each material, half of the prepared specimens were randomly selected and immersed in the disinfectant 24 h prior to testing. Results were compared statistically at a confidence level of 95%. The result showed that in both the control and disinfected groups, the flexural modulus of nylon was significantly lower than the three PMMA polymers. The flexural strength of nylon was significantly lower than those of Meliodent and Acron MC but was comparable with Lucitone 199. A 24-h immersion in the disinfecting solution increased the rigidity of nylon denture base material. PMID:15634304
Yunus, N; Rashid, A A; Azmi, L L; Abu-Hassan, M I
Objective This study investigated the effects of different surface treatments on the tensile bond strength of an autopolymerizing silicone denture liner to a denture base material after thermocycling. Material and Methods Fifty rectangular heat-polymerized acrylic resin (QC-20) specimens consisting of a set of 2 acrylic blocks were used in the tensile test. Specimens were divided into 5 test groups (n=10) according to the bonding surface treatment as follows: Group A, adhesive treatment (Ufi Gel P adhesive) (control); Group S, sandblasting using 50-µm Al2O3; Group SCSIL, silica coating using 30-µm Al2O3 modified by silica and silanized with silane agent (CoJet System); Group SCA, silica coating and adhesive application; Group SCSILA, silica coating, silane and adhesive treatment. The 2 PMMA blocks were placed into molds and the soft lining materials (Ufi Gel P) were packed into the space and polymerized. All specimens were thermocycled (5,000 cycles) before the tensile test. Bond strength data were analyzed using 1-way ANOVA and Duncan tests. Fracture surfaces were observed by scanning electron microscopy. X-ray photoelectron spectrometer (XPS) and Fourier Transform Infrared spectrometer (FTIR) analysis were used for the chemical analysis and a profilometer was used for the roughness of the sample surfaces. Results The highest bond strength test value was observed for Group A (1.35±0.13); the lowest value was for Group S (0.28±0.07) and Group SCSIL (0.34±0.03). Mixed and cohesive type failures were seen in Group A, SCA and SCSILA. Group S and SCSIL showed the least silicone integrations and the roughest surfaces. Conclusion Sandblasting, silica coating and silane surface treatments of the denture base resin did not increase the bond strength of the silicone based soft liner. However, in this study, the chemical analysis and surface profilometer provided interesting insights about the bonding mechanism between the denture base resin and silicone soft liner.
ATSU, Saadet; KESKIN, Yasemin
To evaluate and compare the porosities in the acrylic mandibular denture bases processed by two different polymerization techniques, using two different brands of commercially available denture base resins - an in vitro study
Background: The aim of this study was to evaluate and compare the porosities in the mandibular acrylic denture bases processed by heat and microwave polymerization techniques, using two different brands of commercially available denture base resins. Materials & Methods: Two brands of heat activated denture base resins, DPI plain and Acralyn H cross linked denture base resins designed for conventional water bath polymerization, were used to prepare 48 test specimens of mandibular acrylic denture bases. The test specimens were processed using one cycle of conventional water bath polymerization and one cycle of microwave polymerization. The absolute density of acrylic resin was used to calculate the percent mean porosity of each mandibular acrylic denture base by use of various equations. Results: Anova analysis reveals highly significant difference between mean percent porosity values of whole denture bases of all groups. Statistics reveals that heat polymerized groups have lesser mean percent porosity values than microwave polymerized groups. It also reveals that denture bases processed with Acralyn H cross linked denture base resin have lesser mean percent porosity values than denture bases processed with DPI Plain denture base resin. Conclusion: Specimens processed with Acralyn H cross linked denture base resin by conventional heat polymerization technique has the least mean percent porosity and specimens processed with DPI Plain denture base resin by microwave polymerization technique has the highest mean percent porosity. How to cite the article: Kasina SP, Ajaz T, Attili S, Surapaneni H, Cherukuri M, Srinath HP. To evaluate and compare the porosities in the acrylic mandibular denture bases processed by two different polymerization techniques, using two different brands of commercially available denture base resins - an in vitro study. J Int Oral Health 2014;6(1):72-7.
Kasina, Sitaram Prasad; Ajaz, Tarannum; Attili, Sirisha; Surapaneni, Hemchand; Cherukuri, Muralikrishna; Srinath, H P
This article introduces a technique for modifying an existing mandibular complete denture for use as a radiographic template with a radiopaque light-activated calcium hydroxide (Ca(OH)2) preparation. This allows prosthetically-driven treatment planning and surgical placement of 2 implants to support the existing mandibular denture.
Huynh-Ba, G; Alexander, P; Vargas, A; Vierra, M; Oates, TW
Statement of problem. Acrylic resin complete dentures undergo dimensional changes during polymerization. Techniques with injection molding and polymerization and microwave polymerization are reported to reduce these changes and thereby improve clinical fit. These dimensional changes need to be quantified. Purpose. The purpose of this study was to compare differences in dimensional changes of simulated maxillary complete dentures during polymerization and
Phillip L. J. Keenan; David R. Radford; Robert K. F. Clark
Statement of problem. A clinically significant incisal pin opening may occur after processing complete dentures if a compression molding technique is used. To recover the proper vertical dimension of occlusion, a time-consuming occlusal adjustment is necessary that often destroys the anatomy of the artificial teeth. A new injection molding process claims to produce dentures that require few, if any, occlusal
Sergio S. Nogueira; Robert E. Ogle; Elaine L. Davis
Denture biofilms represent a protective reservoir for oral microbes. The study of the biology of Candida in these biofilms requires a reliable model. A reproducible model of C. albicans denture biofilm was developed and used to determine the susceptibility of two clinically relevant C. albicans isolates against 4 antifungals. C. albicans, growing as a biofilm, exhibited resistance to amphotericin B,
J. Chandra; P. K. Mukherjee; S. D. Leidich; F. F. Faddoul; L. L. Hoyer; L. J. Douglas; M. A. Ghannoum
The aim of this study was to investigate the composition of microcosm denture plaque biofilms and the susceptibility of Candida spp. within these biofilms to antifungal agents. An in vitro model was employed to grow oral biofilms derived from denture associated stomatitis (DAS) patient samples to assess fungal growth in the presence and absence of antifungal agents. The compositions of
Hanadi Lamfon; Zubaida Al-Karaawi; Michael McCullough; Stephen R. Porter; Jonathan Pratten
Wear of the occlusal surface of the denture is a known fact which leads to subsequent changes in jaw relation, vertical dimension, loss of aesthetics, aged looks, and decrease in masticatory efficiency. Treatment modalities includes, change of denture set after a regular interval of 4-5 years, use of wear resistant denture teeth that includes wear resistant resin or porcelain teeth, teeth with cast metal occlusal surface, and altering occlusal contact areas of denture teeth by use of silver amalgam fillings. A case report of a patient who had increased tendency of occlusal wear was treated with custom made metal occlusal surface of denture teeth to enhance wear resistance and to improve the masticatory efficiency.
Shivji, Rizwan Ali; Kamble, Vaibhav D.; Khan, Mohd. Atif
The clinical impression procedures described in this article provide a method of recording the morphology of the intaglio and cameo surfaces of complete denture bases and also identify muscular and phonetic locations for the prosthetic teeth. When the CAD/CAM technology for fabricating complete dentures becomes commercially available, it will be possible to scan the denture base morphology and tooth positions recorded with this technique and import those data into a virtual tooth arrangement program where teeth can be articulated and then export the data to a milling device for the fabrication of the complete dentures. A prototype 3-D tooth arrangement program is described in this article that serves as an example of the type of program than can be used to arrange prosthetic teeth virtually as part of the overall CAD/CAM fabrication of complete dentures. PMID:22230914
Goodacre, Charles J; Garbacea, Antoanela; Naylor, W Patrick; Daher, Tony; Marchack, Christopher B; Lowry, Jean
Wear of the occlusal surface of the denture is a known fact which leads to subsequent changes in jaw relation, vertical dimension, loss of aesthetics, aged looks, and decrease in masticatory efficiency. Treatment modalities includes, change of denture set after a regular interval of 4-5 years, use of wear resistant denture teeth that includes wear resistant resin or porcelain teeth, teeth with cast metal occlusal surface, and altering occlusal contact areas of denture teeth by use of silver amalgam fillings. A case report of a patient who had increased tendency of occlusal wear was treated with custom made metal occlusal surface of denture teeth to enhance wear resistance and to improve the masticatory efficiency. PMID:22997592
Shivji, Rizwan Ali; Kamble, Vaibhav D; Khan, Mohd Atif
'Dentures: A question of grinning and bearing it' is not just the title of a 25-year-old thesis, but it also reflects the content well. Dissatisfaction with complete dentures is not only determined by the quality of the dentures and the oral conditions, but also and just as much by the patient's capacity to adapt to and accept the dentures. In order to treat an edentulous patient adequately, an oral healthcare provider should pay special attention to these aspects. After 25 years of further scientific study, this conclusion is still true. The current care standard for edentulous patients with atrophy of the residual mandibular alveolar ridge is an overdenture supported by 2 implants. For edentulous patients with a solid residual mandibular alveolar ridge, conventional complete dentures are the first choice of treatment. Only in cases of obvious remaining complaints, should an implant-supported overdenture be considered. PMID:21661249
van Waas, M A J
The removal of dentures before having an anaesthetic can be an undignified and distressing event. However, there has been a gradual change in practice and dentures are now often left in place during an anaesthetic. This enquiry into patients' preferences was carried out to find out what patients would like to happen to their dentures, and to see if there were any differences in opinions among age groups. A postal questionnaire was sent out to patients who wore dentures following discharge after surgery. One hundred replies were analysed. There was a spread of opinions across the age groups and by gender. Nurses need to allow patients the choice of what to do in relation to their dentures when going to theatre, although the anaesthetist must make the final decision of whether or not to remove them immediately before the anaesthetic if they feel patient safety could be compromised. PMID:12181510
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
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.
Lau, Mayank; Amarnath, G S; Muddugangadhar, B C; Swetha, M U; Das, Kopal Anshuraj Ashok Kumar
The purpose of this study was to determine which factors related to patient self-assessment of dentures are associated with changes in oral health-related quality of life (OHRQoL) among edentulous patients after replacement of complete dentures, and to determine whether masticatory performance as determined using an objective method affects the changes in OHRQoL among edentulous patients. As a preliminary study, the existing questionnaire regarding self-assessment of dentures consisting of 39 question items, measured with a 100-mm visual analogue scale, was analysed by factor analysis. Then a questionnaire, composed of 22 question items, was developed containing six subscales of 'function', 'lower denture', 'upper denture', 'expectation', 'aesthetic and speech' and 'importance'. Final participants in the present study comprised 93 edentulous patients requiring new conventional complete dentures (44 men, 49 women; mean age, 75·0 years). These patients were asked to complete the Japanese version of the Oral Health Impact Profile (OHIP)-EDENT, comprising 19 question items for assessment of OHRQoL in edentulous patients, along with the developed questionnaire regarding self-assessment of dentures. Moreover, masticatory performance was measured using a colour-changeable chewing gum. The questionnaire and measurement were completed twice; before and after replacement of complete dentures. Stepwise multiple regression analysis identified 'lower denture' and 'aesthetic and speech' as significant independent variables besides OHIP-EDENT scores before replacement. These results suggest that sufficient retention of lower dentures and appropriate appearance may lead to improved OHRQoL in edentulous patients. PMID:22943500
Komagamine, Y; Kanazawa, M; Kaiba, Y; Sato, Y; Minakuchi, S; Sasaki, Y
Overdenture principles can be applied to dentitions that are relatively complete without preparation or alteration of the existing teeth. Such overdentures may cover the traditional denture-bearing tissues as well as the unaltered remaining teeth. The primary advantages derived are reversibility, simplicity, and cost effectiveness. The primary indications are restoration of congenital and acquired anomalies. A detailed clinical and laboratory technique for fabricating these overdentures is presented. Effective restorations require care and attention to detail using the principles of conventional prosthodontics. No special equipment or material is needed. Two patient histories are presented, illustrating use of the technique. PMID:2083008
Rogoff, G S; Graser, G N
The purpose of this paper is to evaluate the incidence of denture repairs in different districts of Croatia through the year of 2002. and to analyse the percentage of different repairs (relinings, simple repairs up to 2 elements and complicated repairs-more than 2 elements) in relation to prosthodontic teams. Data on the number of dentures, and the number and types of denture repairs delivered in the Croatian regions of Zagreb, Rijeka, Split and Karlovac were obtained from the Croatian Institute for Health Insurance for the whole of the year 2002. Information of the number of prosthodontic teams operating in those regions was also obtained. Proportionally more denture repairs were carried out in Karlovac (18%) than Split (5%). The smallest percantage of dentures that required relining was registered in Split and the highest in Rijeka (chi2 = 36.7, p < 0.01). The smallest percentage of simple repairs was registered in Rijeka and the highest in Split (chi2 = 24.3, p < 0.01). The smallest percentage of complicated repairs was registered in Split and the highest in Karlovac. In each region the proportion of denture repairs and types of repairs were correlated with a number of prosthodontic teams in that region. Karlovac had the smallest percentage of specialistic prosthodontic teams and the highest rate of denture repairs. PMID:17058526
Poljak-Guberina, Renata; Celebi?, Asja; Zivkovi?, Ognjen; Guberina, Marko; Muljaci?, Antun
This article evaluated a drug-free oral hydrogel wound dressing composed entirely of natural food ingredients for its ability to relieve pain in immediate denture patients. Evaluation occurred at a 24-hour postoperative appointment. For this crossover study, 44 patients who were taking oral narcotics evaluated their discomfort (using a scale of 0-10) at 1, 3, 5, and 10 minutes after denture insertion with no topical treatment and again after SockIt! Oral Pain Gel was applied to the dentures. The gel provided statistically significant pain relief at all time points beyond that provided by oral narcotic alone (p < 0.0001). PMID:19903626
Kennedy, Thomas J; Hall, John E
Overlay complete dentures are simple, reversible and economical treatment modality for patients with congenital or acquired disorders that severely affect the tooth development. It satisfies both the esthetic and functional demands where the extraction of teeth is not generally indicated. In pediatric patients, the overlay dentures establish a relatively stable occlusion that improves patient's tolerance to the future treatment procedures for worn dentition. This clinical report highlights the imperative need of appropriate treatment strategy and application of maxillary and mandibular overlay dentures in a pediatric patient who suffered from congenitally mutilated and worn dentition. PMID:23236577
Kumar, Prince; Rastogi, Jyoti; Jain, Chandni; Singh, Harkanwal Preet
Overlay complete dentures are simple, reversible and economical treatment modality for patients with congenital or acquired disorders that severely affect the tooth development. It satisfies both the esthetic and functional demands where the extraction of teeth is not generally indicated. In pediatric patients, the overlay dentures establish a relatively stable occlusion that improves patient's tolerance to the future treatment procedures for worn dentition. This clinical report highlights the imperative need of appropriate treatment strategy and application of maxillary and mandibular overlay dentures in a pediatric patient who suffered from congenitally mutilated and worn dentition.
Rastogi, Jyoti; Jain, Chandni; Singh, Harkanwal Preet
The loss of screw is one of the clinic complication in MDIC implant denture cases. The purpose of this study is to find the cause of loss of screw. The authors has studied MDIC implant denture with SEM before and after employ of the screw and found that the causes of screw loss were crevice corrosion and friction pressure. Crevice corrosion may promote the loss of screw. Base the above condition, it is necessary to select Ti-alloy screw and associat with anticorrosive measure in MDIC implant denture construction. PMID:10677963
Song, Y; Xu, J; Ma, X
This study compared the effectiveness of Ricinus communis (RC) with Nystatin (NYS) and Miconazole (MIC) in the treatment of institutionalised elderly with denture stomatitis (DS). They (n = 30) were randomly distributed into three groups: MIC, NYS or RC. Clinical and mycological evaluations were performed prior to the use of the antifungal (baseline) and repeated after 15 and 30 days of treatment. The sample was clinically examined for oral mucosal conditions. Standard photographs were taken of the palate, and the oral candidiasis was classified (Newton's criteria). Mycological investigation was performed by swabbing the palatal mucosa, and Candida spp. were quantified by counting the number of colony-forming units (cfu mL?¹). The clinical and mycological data were analysed, respectively by Wilcoxon and Student's t-test (? = 0.05). Significant improvement in the clinical appearance of DS in the MIC and RC groups was observed between the 1st and 3rd collections (MIC - P = 0.018; RC - P = 0.011) as well as between the 2nd and 3rd collections (MIC - P = 0.018; RC - P = 0.011). Neither groups showed a statistically significant reduction in cfu mL?¹ at any time. Although none of the treatments decreased the cfu mL?¹, it was concluded that Ricinus communis can improve the clinical condition of denture stomatitis in institutionalised elderly patients, showing similar results to Miconazole. PMID:23438045
Pinelli, L A P; Montandon, A A B; Corbi, S C T; Moraes, T A; Fais, L M G
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
The aim of this study was to investigate the composition of microcosm denture plaque biofilms and the susceptibility of Candida spp. within these biofilms to antifungal agents. An in vitro model was employed to grow oral biofilms derived from denture associated stomatitis (DAS) patient samples to assess fungal growth in the presence and absence of antifungal agents. The compositions of genera present in vitro were found to be similar to those exhibited on the mucosa and denture fitting surfaces of DAS samples. Exposure to single agents, e.g., miconazole, fluconazole or chlorhexidine did not inhibit growth of Candida spp. when used in clinically relevant doses. Combinations of miconazole and chlorhexidine, pulsed into the system to mimic patient use, did reduce bacterial and candidal growth for several days. Hence, the use of dual-therapy appeared to be useful in reducing the number of viable organisms within denture plaque grown in vitro although resistance to these agents was also evident. PMID:15621458
Lamfon, Hanadi; Al-Karaawi, Zubaida; McCullough, Michael; Porter, Stephen R; Pratten, Jonathan
Suction cups, which provide high retention, are not being recommended anymore because of the destructive effect of the negative pressure on the palatal tissues. It is known that dentures with suction cups can cause perforations in the palate. In this case report, an oronasal communication caused by a denture with suction cup in a patient who had previously undergone pleomorphic adenoma excision of the palate is presented. Disadvantages of suction cups are emphasized. PMID:16922027
Ordulu, Melike; Emes, Yusuf; Ates, Muzaffer; Aktas, Irem; Yalçin, Serhat
Impacted foreign bodies in the oesophagus are common. Because of their large size, rigidity and pointed edges, dentures get frequently impacted in the oesophagus and are difficult for endoscopic retrieval. Traditional thoracotomy for retrieval of impacted foreign bodies in the thoracic oesophagus is associated with significant morbidity. We present a case of impacted denture in the mid-oesophagus successfully removed using minimal access thoracoscopic procedure.
Dalvi, Abhay N; Thapar, Vinay K; Jagtap, Sachin; Barve, Devyani J; Savarkar, Dattaraj P; Garle, Mahadev N; Shukla, Akash P
A method is presented for measuring interalveolar dimension (IAD) of existing dentures using a caliper. Directions for construction of an IAD gauge are included. This device is easy to construct and "zeroes out" in the closed position. The measurement is useful for determining occlusal vertical dimension (OVD) in new dentures and for monitoring changes over time. Its dimension is entered in the patient record for future reference. PMID:18544134
Pitigoi-Aron, Gabriela; Labarre, Eugene; Giusti, Lola; Leknius, Casimir
Objectives: Given the need to ensure that dentists are sufficiently skilled to offer the best possible care to their patients, this study aims to evaluate the teaching methods and clinical experience achieved by undergraduate dental students in Spain and Portugal as regards complete dentures. Study design: In February 2011, a questionnaire seeking information about the preclinical and clinical teaching of complete dentures was e-mailed to all Spanish and Portuguese dental schools with fully developed undergraduate degree dental programs. Results: A response rate of 82.6% was obtained. The distribution of lectures and hours spent at the laboratory and in clinical activities revealed that teaching complete dentures is eminently a practical issue, this being mostly performed by full-time prosthodontists. All surveyed schools teach the design of the record base, and most of them instruct students in the mounting of teeth in wax. Most schools (94.7%) used a semiadjustable articulator, alginate for primary impressions (73.7%) and elastomeric materials in border-molded custom trays for final impressions (68.4%). In most schools, within the clinical setting students work in pairs, the mean student/ professional staff member ratio being 2.3 ± 0.7. Most schools perform a competence-based assessment (83.3%), although innovative techniques such as problem-based learning are still rarely applied. On average, the students emplaced 1.8 ± 1.2 complete dentures during their clinical training, ranging from 0 to 4, although no clear trend was seen as regards the minimum number of dentures to be made for graduating. Conclusions: Variations in teaching programs and clinical experience concerning complete denture curricula among Spanish and Portuguese dental schools are evident, but all the schools base their teaching mainly on preclinical and clinical practice. However, the low number of dentures made by student per year seems insufficient to ensure clinical skills and cope with social needs. Key words:Dental education, questionnaires, complete dentures, curricula.
Castillo-de Oyague, Raquel; Albaladejo, Alberto
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.
Bagis, Bora; Ozcan, Mutlu; Durkan, Rukiye; Turgut, Sedanur; Ates, Sabit Melih
The main goal of prosthetic treatment is to restore masticatory function. However, insufficient evidence supports the recommendation of one specific prosthetic intervention for partially edentulous patients. Function after the use of three different prostheses by the same partially edentulous subject. Mastication was assessed in 12 subjects (mean age 62·6 ± 7·8 years) after they had used removable partial dentures (RPDs), implant-supported partial dentures (IRPDs) and implant-fixed partial dentures (IFPDs). Masticatory ability (MA) was estimated by visual analogue scale questionnaire, while the mandibular chewing motion was evaluated by kinesiographic device, representing an objective measurement of masticatory function. Data were analysed by repeated-measures anova followed by Tukey-Kramer (P < 0·05). MA improved after IRPD and IFPD use (P < 0·05). Opening, closing and total cycle time duration were reduced after both IRPD and IFPD use (P < 0·05), irrespectively the implant prosthesis type. IFPDs and IRPDs restore the masticatory function of partially edentulous patients better than RPDs. PMID:24750471
Gonçalves, T M S V; Campos, C H; Rodrigues Garcia, R C M
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®.
Huh, Jung-Bo; Lim, Younghun; Youn, Hye-In; Chang, Brian Myung; Lee, Jeong-Yol
This work attempted to integrate the technologies of computer-aided design and computer-aided manufacture (CAD/CAM) and laser rapid forming (LRF) for the fabrication of the titanium plate of a complete denture. By the combination of laser scan and reverse engineering software, the standard triangulation language (STL)-formatted denture base plate was finally designed and sliced into a sequence of numerical controlled codes. The titanium (Ti) complete denture plate was finally built, layer-by-layer, on the LRF system. To evaluate the quality of fit, a virtual adaptation test that measured and compared the profiles of the laser free formed denture plate and those of the edentulous plaster cast had been conducted, and the mean deviation was found to be 0.34 mm. After traditional dental finishing techniques, a complete denture with a Ti base plate was then made and judged to be acceptable. The CAD/CAM/LRF system is a potential candidate and a new platform for the design and manufacture of custom-made Ti denture plates and restorations. PMID:18716825
Wu, Jiang; Gao, Bo; Tan, Hua; Chen, Jing; Tang, Chak-Yin; Tsui, Chi-Pong
The aim of this study was to isolate, quantify, identify, and compare opportunistic microorganisms (Candida and Staphylococcus genera and Enterobacteriaceae/Pseudomonadaceae families) from prosthesis-fitting surfaces, the hard palate, and mouth rinses of individuals wearing removable maxillary prosthesis with (50) and without (50) lesions of denture stomatitis (DS). The strains were collected and identified using phenotypic, biochemical and molecular tests. The counts of microorganisms were significantly higher in the group of individuals with DS (P < 0.05). C. albicans was the most frequently isolated yeast species in both groups, following by C. tropicalis and C. glabrata. Six isolates were identified as C. dubliniensis. S. aureus and S. epidermidis were the most frequent Staphylococcus species in both groups. Klebsiella pneumoniae was the predominant species in both groups. The association between Candida spp. and bacteria isolated in this study with DS suggests that these microorganisms may play important roles in the establishment and persistence of this disease. PMID:23747028
Pereira, Cristiane Aparecida; Toledo, Bruna Costa; Santos, Camila Teles; Pereira Costa, Anna Carolina Borges; Back-Brito, Graziella Nuernberg; Kaminagakura, Estela; Jorge, Antonio Olavo Cardoso
The prosthodontic treatment must provide for the edentulous patients bio-functional prosthetic restorations, bio-prophylactic for the surrounding tissues. In this aim, an edentulous patient must be submitted to a methodical clinical examination in order to establish the quality of hard and soft tissues, which will indicate the degree of difficulty of the prosthetic treatment. Additional investigation as a microbiologic examination and cephalometric radiographs can be useful in a modern investigation. In our daily practice, we are rarely confronted with a normal morphology of the denture bearing oral structures. The problem of managing abused tissues in a patient with morphologic abnormalities due to faulty prostheses is sometimes difficult to solve. Preventing the deterioration of oral status must be a condition in providing a chance for the success of the following rehabilitations, mainly in the situation when the complete edentulousness succeeds in a young or middle age patient. PMID:19942970
Babiuc, Iuliana; P?una, Mihaela; Mali?a, M?d?lina Adriana; Ariton, Simona Georgiana; Damian, Maria; Ungureanu, Vasilica; Petrini, Anca
Follow-up, maintenance, and treatment of complications of 81 mandibular subperiosteal implants placed at the University of Southern California Advanced Prosthodontic Clinic were recorded for periods up to 21 years. Few patients were lost to follow-up, but a significant number of patients died before termination of the study. A 10-year survival rate of 79% was calculated for 63 patients, and a 15-year survival rate of 60% was calculated for 34 patients. It was found that subperiosteal implants have a low long-term survival rate, and the rate of loss of subperiosteal implants increases over time without reaching a steady state. However, subperiosteal implant therapy did provide function for patients who otherwise could not use dentures. PMID:8196000
Yanase, R T; Bodine, R L; Tom, J F; White, S N
Complete dentures often fracture during normal masticatory function. The reason could be due to the shape of the palate, i.e. deep, medium or shallow palatal vault. This in vitro study was performed to determine the relationship of palatal vault depth and fexural strength of two different permanent denture base resins. Edentulous maxillary casts of patients were collected from the department of prosthodontics, among these the cast with the deepest palatal vault was selected. The specimens were then subjected for fexural strength on universal testing machine. The results revealed that the denture bases fabricated on medium palatal vault depth were best in the fexural strength and denture bases on shallow palatal vault depth faired the least. Among the resins the denture bases fabricated using high impact heat cure resin, were better than the denture bases fabricated using regular heat cure resin. All these results were statistically signifcant except the results between the regular heat cure denture bases and high impact heat cure denture bases fabricated on the deep palatal vault depth. Also the comparison of fracture energies of denture bases fabricated on deep palatal vault with high impact heat cure resin to denture bases fabricated on medium and shallow palatal vaults with high impact heat cure resin were not signifcant. It was also observed that all the specimens have fractured in the midline. Clinical implications: Palatal vault depth signifcantly affected the fexural strength of heat cure resin. The most frequent mechanical failure of heat cure resin is fracture especially at the midline. The denture bases fabricated using high impact heat cure resin had best fexural strength than the denture bases fabricated using regular heat cure resin which reduced the fractures. Keywords: Flexural strength, Palatal vault, Denture base resins, Complete dentures. How to cite this article: Reddy BMM, Himabindu M, Padmaja BI, Sunil M, Reddy NR. Palatal Vault Depth Infuence on the Flexural Strength of Two Heat Cure Acrylic Denture Base Resins: An in vitro Study. J Contemp Dent Pract 2013;14(6):1131-1136. Source of support: Nil Confict of interest: None. PMID:24858763
Reddy, B Madan Mohan; Himabindu, M; Padmaja, B Indira; Sunil, M; Reddy, N Raja
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
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.
Krishna, V Pridhvi; Premalatha, Averneni; Babu, P Jithendra; Raju, D Srinivasa; Kumar, M Praveen; Rao, D Bheemalingeswara
Several studies have compared complete dentures fabricated using conventional and neutral zone (NZ) techniques. However, studies comparing patient satisfaction with complete dentures fabricated using swallowing and phonetic NZ techniques are lacking in literature. To compare patient satisfaction with the complete dentures fabricated using the two NZ techniques. To compare the bucco-lingual dimensions of the NZ records obtained with these techniques. Ten completely edentulous subjects dissatisfied with their existing mandibular complete dentures participated in the study. Five subjects first received the swallowing neutral zone (SNZ) dentures and five the phonetic neutral zone (PNZ) dentures. Tissue conditioner was used as the recording material in both the techniques. After having worn the prosthesis for a minimum of 2 months, subjects responded to a questionnaire that measured their perceptions of various factors associated with the prosthesis. The prostheses were then changed and the procedures repeated. Student t test and non-parametric Mann-Whitney tests were used for statistical analysis. Level of statistical significance was set p < 0.05. There was no statistical significant difference in patient satisfaction with the SNZ and PNZ complete dentures for all the variables assessed. Statistical significant difference was observed for majority of the variables when the two NZ dentures were compared with patients' old dentures. The difference in the mean dimensions of the two NZ records was also found to be statistically insignificant except in the maxillary left premolar region. The study indicated that patient satisfaction with the complete dentures fabricated using SNZ technique did not significantly differ from that of the PNZ technique. Data gathered at the final appointment showed that SNZ dentures were preferred by the patients with regards to esthetics, stability, comfort and ability to chew. For ability to speak, mixed preferences were found. PMID:24757353
Ladha, Komal; Gupta, Rekha; Gill, Shubhra; Verma, Mahesh
The conventional fabrication of complete dentures involves two separate clinical sessions for functional impression making and jaw registration. The presented method combines both procedures in one session. The aim of this study was to survey the three-dimensional tooth positions in complete dentures with reference to the ridges to establish arbitrary guideline values that could be used for the manufacturing of tooth-position analogue plastic rims on functional impression trays. New complete dentures were fabricated by supervised undergraduate students in the conventional manner for 104 edentulous patients. The position of the maxillary teeth was surveyed in the horizontal plane using the Schmuth 'vizor-measuring plate'. The vertical dimension of occlusion, represented as the distance between opposing ridge areas of the dentures in maximum intercuspation, was measured at different sites by means of a Gutowski gauge. The tooth positions on the dentures varied widely, e.g. the horizontal distances between the incisive papilla and the maxillary incisors was 7.1 +/- 2.3 (3-14) mm. The vertical dimension of occlusion, which is most important in the jaw registration, varied equally with an anterior inter-alveolar distance between 12 and 33 (20.4 +/- 4.0) mm. Arbitrary moulding of the tooth position-analogue plastic rims does not seems to be an ideal method of pre-shaping functional impression trays, because the individual anatomical variation is considerable. Alternatively, the horizontal and vertical tooth positions of functionally and aesthetically pleasing dentures should be measured to pre-shape the rims of functional impression trays in the maxillary and the mandibular jaw. Such trays are a valuable tool for functional impressions and an immediate preliminary jaw registration in the fabrication of new complete dentures. This method allows a first try-in of the full set-up in the third clinical visit without loosing precision. PMID:15189312
Utz, K-H; Müller, F; Kettner, N; Reppert, G; Koeck, B
Dental rehabilitation of edentulous patients with complete dentures includes not only aesthetics and mastication of food, but also speech quality. It was the aim of this study to introduce and validate a computer-based speech recognition system (ASR) for automatic speech assessment in edentulous patients after dental rehabilitation with complete dentures. To examine the impact of dentures on speech production, the speech outcome of edentulous patients with and without complete dentures was compared. Twenty-eight patients reading a standardized text were recorded twice - with and without their complete dentures in situ. A control group of 40 healthy subjects with natural dentition was recorded under the same conditions. Speech quality was evaluated by means of a polyphone-based ASR according to the percentage of the word accuracy (WA). Speech acceptability assessment by expert listeners and the automatic rating of the WA by the ASR showed a high correlation (corr = 0.71). Word accuracy was significantly reduced in edentulous speakers (55.42 +/- 13.1) compared to the control group's WA (69.79 +/- 10.6). On the other hand, wearing complete dentures significantly increased the WA of the edentulous patients (60.00 +/- 15.6). Speech production quality is significantly reduced after complete loss of teeth. Reconstitution of speech production quality is an important part of dental rehabilitation and can be improved for edentulous patients by means of complete dentures. The ASR has proven to be a useful and easily applicable tool for automatic speech assessment in a standardized way. PMID:20085615
Stelzle, F; Ugrinovic, B; Knipfer, C; Bocklet, T; Nöth, E; Schuster, M; Eitner, S; Seiss, M; Nkenke, E
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.
Objective Chemical solutions have been widely used for disinfection of dentures, but their effect on color stability of denture tooth acrylic resins after repeated procedures is still unclear. The aim of this in vitro study was to evaluate whether repeated cycles of chemical disinfectants affected the color stability of two denture tooth acrylic resins. Material and Methods Sixty disc-shaped specimens (40 mm x 3 mm) were fabricated from two different brands (Artiplus and Trilux) of denture tooth acrylic resin. The specimens from each brand (n=30) were randomly divided into 6 groups (n=5) and immersed in the following solutions: distilled water (control group) and 5 disinfecting solutions (1% sodium hypochlorite, 2% sodium hypochlorite, 5.25% sodium hypochlorite, 2% glutaraldehyde, and 4% chlorhexidine gluconate). Tooth color measurements were made by spectrophotometry. Before disinfection, the initial color of each tooth was recorded. Further color measurements were determined after subjecting the specimens to 7, 21, 30, 45, 60, and 90 immersion cycles in each tested solution. Color differences (?E*) were determined using the CIE L*a*b* color system. Data were analyzed using two-way repeated measures analysis of variance (ANOVA) followed by Tukey tests. The significance level was set at 5%. Results There were statistically significant differences in ?E* among the 5 disinfectants and water during the 90 cycles of immersion for both denture tooth acrylic resins. Distilled water promoted the greatest color change in both denture tooth acrylic resins, nevertheless none of tested disinfectants promoted ?E* values higher than 1.0 on these acrylic materials during the 90 cycles of disinfection. Conclusions Repeated immersion cycles in disinfecting solutions alter ?E* values, however these values do not compromise the color of the tested denture tooth acrylic resins because they are imperceptible to the human eye.
da SILVA, Paulo Mauricio Batista; ACOSTA, Emilio Jose Tabare Rodriguez; JACOBINA, Matheus; PINTO, Luciana de Rezende; PORTO, Vinicius Carvalho
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.
Uludag, Bulent; Tokar, Emre; Polat, Serdar
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.
CARDELLI, P.L.; VERTUCCI, V.; BALESTRA, F.; MONTANI, M.; ARCURI, C.
Dental implants treatment have become a common modality of treatment nowadays for the replacement of missing tooth/teeth, but there have been failures due to a number of reasons; one of the rare problems is the fracture of the dental implants fixture. It is of prime importance to understand the type/system of the implant to be placed in a site and the amount and direction of occlusal forces incurred after the loading of prosthesis. PMID:23709559
Yadav, Ashish; Gupta, Aratee; Tandan, Amrit; Kumar, Sulabh
PURPOSE The objective of this study was to evaluate fracture strength of collarless metal-ceramic FPDs according to their metal coping designs. MATERIALS AND METHODS Four different facial margin design groups were investigated. Group A was a coping with a thin facial metal collar, group B was a collarless coping with its facial metal to the shoulder, group C was a collarless coping with its facial metal 1 mm short of the shoulder, and group D was a collarless coping with its facial metal 2 mm short of the shoulder. Fifteen 3-unit collarless metal-ceramic FPDs were fabricated in each group. Finished FPDs were cemented to PBT (Polybutylene terephthalate) dies with resin cement. The fracture strength test was carried out using universal testing machine (Instron 4465, Instron Co., Norwood MA, USA) at a cross head speed of 0.5 mm/min. Aluminum foil folded to about 1 mm of thickness was inserted between the plunger tip and the incisal edge of the pontic. Vertical load was applied until catastrophic porcelain fracture occurred. RESULTS The greater the bulk of unsupported facial shoulder porcelain was, the lower the fracture strength became. However, there were no significant differences between experimental groups (P > .05). CONCLUSION All groups of collarless metal-ceramic FPDs had higher fracture strength than maximum incisive biting force. Modified collarless metal-ceramic FPD can be an alternative to all-ceramic FPDs in clinical situations.
Yoon, Jong-Wook; Kim, Sung-Hun; Lee, Jai-Bong; Han, Jung-Suk
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
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.
Tugut, Faik; Mutaf, Burcu; Guney, Umit
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
Statement of problem. Despite the favorable properties of conventional PMMA used as a denture base material, its fracture resistance could be improved. Purpose. This in vitro study was performed to determine whether the flexural strength of a commercially available, heat-polymerized acrylic denture base material could be improved through reinforcement with 3 types of fibers. Material and methods. Ten specimens of
Jacob John; Shivaputrappa A. Gangadhar; Ila Shah
Eluates from poly(methyl methacrylate)-based denture base polymers have recently been found to enhance death by apoptosis and necrosis in U-937 human monoblastoid cells. The present study investigated the potential of such polymers to induce apoptosis and/or necrosis and to alter clonogenicity in L929 murine fibroblasts. A fibroblast cell line was chosen because the impairment of fibroblasts subjacent to denture bases may result in a weaker or more permeable mucosa. Two aspects were addressed: the effect of direct contact with the denture base polymers and the effect of eluates extracted from the polymers. For this purpose L929 fibroblasts were seeded on disks manufactured from three heat-polymerized and four autopolymerized denture base polymers or in different concentrations of their eluates. The effects were evaluated by light, fluorescent, confocal and electron microscopy, counting of colonies, and flow cytometry. Disks and eluates of all polymers enhanced cell death by apoptosis and necrosis in L929 cells and decreased their clonogenic potential in a dose-dependent manner. Apoptosis was the main form of cell death. In general, the deleterious effects were stronger when cells were plated directly on the polymer disks than in the eluates. The autopolymerized polymers, except one, yielded higher percentages of apoptosis and necrosis than the heat-polymerized polymers. The results of the study indicated that poly(methyl methacrylate)-based denture base polymers trigger death-signals in L929 fibroblasts and open doors for possible modulation of the cell/biomaterial interaction. PMID:11144873
Cimpan, M R; Matre, R; Cressey, L I; Tysnes, B; Lie, S A; Gjertsen, B T; Skaug, N
Poly(methyl methacrylate) dentures may exhibit dimensional changes when drying. Drying has been shown to destroy Candida albicans. This study investigates the effect of simulating overnight cyclic drying on dimensional changes of four complete denture base materials. Denture specimens used in this study had been prepared for a previous study. All dentures had been kept hydrated at room temperature for 2 years. The materials used were, group 1, conventionally packed and cured Trevalon, group 2 was injection moulded and conventionally cured (Trevalon Success), group 3 (Acron MC) and group 4 was Microbase, which is injection moulded and microwave cured. The measurements of the inter-molar and inter-premolar width, and anterior posterior dimension between the premolars and molars were recorded after 8 h drying and then after four cycles of dehydration and rehydration. The dentures were more dimensionally stable in the anterior posterior than the cross arch dimension. There was a statistically significant (P < 0.02) increase in the intermolar width for Trevalon, Trevalon Success and Acron after 8 h drying and after four cycles. There was a statistically significantly difference between Microbase and the other materials after 8 h drying and there was a significant difference between the injection moulded groups in the interpremolar width (Trevalon Success versus Acron, Trevalon Success versus Microbase) after cyclic drying. Although statistically significant dimensional changes were observed for all materials these were small and were considered not to be clinically significant. Microbase was the least dimensionally stable material during air-drying. PMID:16922738
Shukor, S S A B D; Juszczyk, A S; Clark, R K F; Radford, D R
The purpose of this study was to evaluate dental students' performance when fabricating a mandibular two-implant overdenture (OD) as compared to conventional dentures (CD) and to determine if these prostheses were successful. Twenty students and twenty patients were divided into two groups: complete denture group (CDG) and maxillary denture and two-implant OD group (ODG). Students' progress was evaluated at each appointment as they were given a clinical assessment score (CAS), which varied from 1 (unacceptable, needs to repeat procedure) to 4 (acceptable, no errors). The success of the prosthesis was evaluated by the patients using a visual analog scale (VAS) and an expert (a prosthodontist) using a denture quality assessment (DQA) form. Performance for both groups was not statistically different across all eight appointments (CDG 3.16 versus ODG 3.25; p=0.46). Patients with ODs reported greater stability with their dentures (p=0.048) and greater ability to chew than patients with CDs (p=0.03). There were no differences between the groups in terms of expert appraisal (ODG 71.1 versus CDG 67.5; p=0.59). The performance of dental students when fabricating a two-implant OD is thus not different from that of a CD. Students can successfully fabricate a two-implant OD as perceived by both patients and prosthodontists. PMID:20837741
Aragon, Cecilia E; Cornacchio, Angelica Lee Petrina; Ibarra, Lilia Marcela; Saad, Muhammed N; Zibrowski, Elaine
The paper presents the results of the study of the titanium implant-elastomeric membrane attachment, conducted from the point of view of potential utilization of the results in forecasting the durability of retention elements representing a new solution of dentures based on implants. The examination was carried out using a device designed by the author, which allowed the simulation of the process of inserting and removing dentures. Titanium counter specimens, simulating implants, were subjected to surface modification through their sandblasting with 350 um and 500 um abrasives, so as to diversify their roughness. The elastomeric membranes constituting a retention element of the attachment were made of a silicone material, Molloplast B. The influence of the number of cycles (one cycle meaning one insertion and removal of a denture) on the attachment's retention force was studied. In order to better reflect the natural conditions, the device was equipped with a chamber which made it possible to perform the examination in an artificial saliva environment. The study has shown that the application of the polymer material Molloplast B for constructing the new type retention elements of dentures based on implants ensures practically constant values of the attachment's retention force in the required 6-month utilization period. After the time of denture usage, being eight times longer than originally assumed, the loss of retention force does not exceed 43% in any of the attachments investigated and the retention force values still allow the attachments to operate, although their effectiveness is partly reduced. PMID:19152467
Purpose The addition of anionic charge on denture base resins has been shown to inhibit Candida albicans adhesion and to facilitate adsorption of salivary defense molecules. The aim of this study was to evaluate the physical properties of a modified denture base resin for denture fabrication. Materials and Methods Specimens made from heat polymerizing resin Lucitone 199 were used as the control group. The two experimental groups, E-10 and E-20, had 10% and 20%, respectively, of the monomer substituted with an experimental phosphate-containing monomer. Flexural strength and modulus, water sorption, solubility, and color stability tests were conducted to ensure compliance with ADA specification No. 12. Water diffusion coefficient into the resins and stainability were also assessed. ANOVA and Scheffe tests were performed for statistical significance. Results There was an overall decline in all properties with the addition of the experimental phosphate compound. The flexural strength and modulus, water sorption and solubility for E-10, as well as the control were, however, within the ADA specifications. The diffusion coefficients were significantly different (p < 0.05) for the three groups. Staining and color specimens showed no significant difference (p > 0.05) among the three groups. Conclusions Within the limitations of this study, the physical properties of the phosphate denture base resin at 10% should be suitable for denture fabrication based on the properties assessed.
Dhir, Gunjan; Berzins, David W.; Dhuru, Virendra B.; Periathamby, A. Raj; Dentino, Andrew
The objective of the study was to evaluate the hypothesis that the mechanical properties and fatigue behavior of removable partial dentures (RPD) made from cast titanium alloys can be improved by alloying with low-cost, low-melting elements such as Cu, Al, and Fe using commercially pure Ti (CP-Ti) and Ti-6Al-4V as controls. RPD specimens in the form of rest-shaped, clasp, rectangular-shaped specimens and round-bar tensile specimens were cast using an experimental Ti-5Al-5Cu alloy, Ti-5Al-1Fe, and Ti-1Fe in an Al2O3-based investment with a centrifugal-casting machine. The mechanical properties of the alloys were determined by performing tensile tests under a controlled displacement rate. The fatigue life of the RPD specimens was tested by the three-point bending in an MTS testing machine under a cyclic displacement of 0.5 mm. Fatigue tests were performed at 10 Hz at ambient temperature until the specimens failed into two pieces. The tensile data were statistically analyzed using one-way ANOVA (? = 0.05) and the fatigue life data were analyzed using the Kaplan-Meier survival analysis (? = 0.05). The experimental Ti-5Al-5Cu alloy showed a significantly higher average fatigue life than that of either CP-Ti or Ti-5Al-1Fe alloy ( p < 0.05). SEM fractography showed that the fatigue cracks initiated from surface grains, surface pores, or hard particles in surface grains instead of the internal casting pores. Among the alloys tested, the Ti-5Al-5Cu alloy exhibited favorable results in fabricating dental appliances with an excellent fatigue behavior compared with other commercial alloys.
Koike, Mari; Chan, Kwai S.; Hummel, Susan K.; Mason, Robert L.; Okabe, Toru
Background: The objectives of this study were to evaluate the prevalence of edentulousness, patient’s perception on dietary changes resulting from tooth loss and to identify the disparity between actual and patient perceived need to replace missing teeth in an elderly rural population in south India. Methods: A cross sectional study using the systematic cluster sampling method was used to select the study sample of 150 elderly men and women. Data were collected using questionnaires and oral examination. The data were statistically analyzed using chi square test and pearson correlation. Results: 15.6% of the rural elderly were completely edentulous and 54.7% were partially edentulous. Observed differences in distribution between the sampled elderly age groups were found to be statistically significant. Although 70.3% of the evaluated elderly actually required prosthodontic treatment, only 14.4% perceived the need to replace missing teeth. A small percentage of the elderly (18%) perceived a severe change in their diets due to tooth loss. Thirty three percent of them perceived a moderate change and 28% felt that there were no dietary changes because of tooth loss. Conclusions: It is essential to identify feasible strategies to provide primary dental health education and treatment to all rural elderly in the future. We suggest community dental health services as a general health need of the elderly rather than a special health need of the community.
Ariga, P; Bridgitte, A; Rangarajan, V; Philip, J M
The impact of oral health on the quality of life of older individuals have significantly increased over the last few decades. Edentulism substantially affect oral and general health and overall quality of life. Complete denture retention is the resistance to displacement of the denture base away from the ridge which is the main source of psychological comfort for the patient. Special retention problems are seen in patients exhibiting highly tapered steep palatal vault. In these cases a metal base or subsequent bench cure reline procedure would be incorporated into the initial treatment plan. In this article, we have derived a mathematical proof for the clinical experience that reduction in the palatal angle, results in lesser denture retention. PMID:24757354
Mathew, Liji; Unni, K N; Vijayakumar
Due to the changes in the composition and processing of acrylic resins, it seems appropriate to evaluate the influence of polymerization methods about the alteration of occlusal vertical dimension and the horizontal positioning of artificial teeth of total dentures. For this, 64 specimens were made, simulating a maxillary total denture waxed from a standard maxillary denture. The experimental samples were divided into two groups: Group 1 - The resins were submitted to polymerization in a hot water bath, Group 2 - The same resins were submitted to poly-merization by microwave energy. The samples were measured horizontally and vertically before and after the polymerization process. Based on the results, it can be concluded that there was no statistically significant difference between the conventional polymerization method and the polymerization method by microwave, related to the stability of occlusal vertical dimension and horizontal positioning of artificial teeth on the specimens evaluated. PMID:22165322
Slaviero, Thiago V S; Simon, Gabriel H P; Tagliari, Ivânio; Busato, Priscila M R; Sinhoreti, Mario A C; Camilotti, Veridiana; Mendonça, Marcio J
In this study, the wear resistance, hardness, elastic modulus, and the correlations between them of artificial denture teeth at the sub-enamel layer were examined. Four types of tested artificial denture teeth consisted of 3 conventional acrylic resin teeth (Cosmo HXL, Major Dent, and Yamahachi FX), 1 high cross-linked acrylic resin teeth (Trubyte Bioform IPN), 2 composite resin teeth (SR Orthosit PE, and Yamahachi PX), and 1 porcelain teeth (ACE Teeth). The two-body wear test was performed using a custom made pin on disc apparatus. Volume and weight loss were measured. Hardness and elastic modulus were also assessed by using a nanoindentation system. The results suggested wear resistance varied among the denture tooth materials. Wear resistance of high cross-linked acrylic resin teeth was the lowest. A definite relation between wear resistance and mechanical properties of materials could not be found in this study. PMID:21778606
Suwannaroop, Pii; Chaijareenont, Pisaisit; Koottathape, Natthavoot; Takahashi, Hidekazu; Arksornnukit, Mansuang
Background Poor oral health, chronic diseases, functional decline, and low cognitive ability can increase the risk of falls in the elderly. Objectives The current study aimed to show the effects of oral health, diabetes mellitus (DM), hypertension (HT), heart disease, functional status, and sociodemographic factors on the risk of falls in elderly with dementia. Materials and methods The sample comprised 1,210 Malaysian elderly who were demented and noninstitutionalized. This study was a national cross-sectional survey entitled “Determinants of Health Status among Older Malaysians”. The effects of age, ethnicity, sex differences, marital status, educational level, oral health, DM, HT, heart disease, and functional status on the risk of falls were evaluated. The multiple logistic regression model was used to estimate the effects of contributing variables on the risk of falls in samples. Results The prevalence of falls was approximately 17% in subjects. It was found that age (odds ratio [OR] 1.02), non-Malay ethnicity (OR 1.66), heart disease (OR 1.92), and functional decline (OR 1.58) significantly increased the risk of falls in respondents (P<0.05). Furthermore, having teeth (OR 0.59) and dentures (OR 0.66) significantly decreased the rate of falls (P<0.05). Conclusion It was concluded that age, non-Malay ethnicity, functional decline, heart disease, and oral health significantly affected falls in dementia.
Eshkoor, Sima Ataollahi; Hamid, Tengku Aizan; Nudin, Siti Sa'adiah Hassan; Mun, Chan Yoke
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.
Wieckiewicz, Mieszko; Richter, Gert; Boening, Klaus W.
Obtaining a satisfactory outcome for a patient with a severely resorbed maxilla can be extremely challenging. This clinical report describes the treatment of a patient with a history of multiple implant failures in the maxilla. A conventional upper complete denture had poor retention and so did not fulfil the patient's needs. Further surgery was not considered appropriate. A new upper complete denture was made with a fitting surface covered in multiple suction cups to attempt to improve the retention without surgery and resulted in a pleasing outcome for both the patient and authors. PMID:22576499
Vasant, R; Bassi, G S
Retention for a denture on a ramus frame implant is usually less satisfactory. The friction between the frame and denture is not reliable. Locking-type attachments require manual dexterity, which could be a problem for many patients. This article presents a technique of cementing the stud-type attachments to the ramus frame to convert the retention mechanism from one that uses the friction between the acrylic resin and ramus frame to a conventional resilient precision attachment. The retention can also be adjusted by changing the nylon inserts. PMID:22121945
Hsu, Yung-tsung; Sigurjonsson, Jon Olafur; Montes, Carlos A Polo
Background Demand for complete denture treatment is expected to rise over several decades. However, to date, no questionnaire on complete dentures, as evaluated by edentulous patients, has been shown to be reliable and valid. This study sought to assess the reliability and validity of Patient’s Denture Assessment (PDA), which provides a multidimensional evaluation of dentures among edentulous patients. Methods Patients, who had new complete dentures fabricated at the University Hospital of Dentistry, Tokyo Medical and Dental University through 2009 to 2010, were enrolled. The reliability of the PDA was determined by examining internal consistency and test-retest reliability. Internal consistency for all of the question items and the six subscales was measured using Cronbach’s ? and average inter-item correlation coefficients among 93 participants. For 33 of these participants, test-retest reliability was determined at a 2 month-interval using the interclass correlation coefficients (ICCs) and 95% confidence interval for the summary scores and the six subscale scores. The PDA was validated in 93 participants by examining the difference in the summary score and the six subscale scores of the PDA before and after replacement with new dentures by the paired t-test. Ability to detect change was also tested in 93 patients using effect size. Results The Cronbach’s ? for the PDA ranged from 0.56 to 0.93. The average inter-item correlation coefficients ranged from 0.28 to 0.83. ICCs for the PDA ranged from 0.37 to 0.83. The paired t-test showed a significant difference between the summary score and the six subscale scores before and after replacement with new dentures (p?0.05) and the effect size was 0.97. Conclusions The PDA demonstrated good reliability by assessing internal consistency and test-retest reliability. In addition, the PDA demonstrated good validity by assessing discriminant validity. Thus, the PDA could help dentists obtain a detailed understanding of the patients’ perceptions in using their dentures.
The use of computer-aided design and computer-aided manufacturing (CAD/CAM) has become available for complete dentures through the AvaDent and Dentca systems. AvaDent uses laser scanning and computer technology. Teeth are arranged and bases formed using proprietary software.The bases are milled from prepolymerized pucks of resin. Dentca uses computer software to produce virtual maxillary and mandibular edentulous ridges, arrange the teeth and form bases. The dentures are fabricated using a conventional processing technique. PMID:23875432
Kattadiyil, Mathew T; Goodacre, Charles J; Baba, Nadim Z
Acrylic resin is widely used for artificial teeth manufacturing due to several important characteristics; however, this material do not present acceptable colour stability over the course of time. This study evaluated the effect of different cleaning protocols and accelerated artificial aging on colour stability of denture teeth made of acrylic resin. Sixty denture teeth in dark and light shades were used, and separated according to the treatment to which they were submitted. Results demonstrated that colour stability of artificial teeth is influenced by the cleaning solution and artificial aging, being dark teeth more susceptible to colour alteration than lighter ones. PMID:24922996
Freire, T S; Aguilar, F G; Garcia, L da Fonseca Roberti; Pires-de-Souza, F de Carvalho Panzeri
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
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
Among the millions of edentulous Americans, a persistent minority have not been able to tolerate wearing dentures. Complicating factors may have precluded surgical intervention with grafts or dental implants to improve the physical and anatomic limitations of these unfortunate patients. A heat-cured polymer liner containing multiple small suction cups has been used for decades to successfully restore many such debilitated individuals. Two middle-aged female patients with edentulous maxillae and near fully dentate mandibles had both reached a point where they could no longer retain a maxillary complete denture, or function with it. Both had experienced multiple failed surgical attempts to improve their situations. They were both successfully restored with maxillary complete dentures containing heat-cured silicone liners with multiple small suction cups. Two young female maxillectomy patients had significant difficulties wearing maxillary obturators due to defect size and absence of defect undercuts. One had an edentulous maxilla, while the other had no axial undercuts on her few remaining maxillary teeth. Without an obturator, both suffered considerable air and fluid leaks, unintelligible speech, and swallowing problems. They too were successfully restored with obturators containing a heat-cured, multi-cup, silicone liner. The multi-cup, silicone denture liner has offered an economic, noninvasive alternative for patients unable or unwilling to undergo surgical intervention to facilitate prosthesis retention. PMID:17927734
Engelmeier, Robert L; Gonzalez, Maria L; Harb, Maribel
Soft denture-lining materials are an important treatment option for patients who have chronic soreness associated with dental prostheses. Three distinctly different types of materials are generally used. These are plasticized polymers or copolymers, silicones, or polyphosphazene fluoroelastomer. The acceptance of these materials by patients and dentists is variable. The objective of this study is to compare the tensile strength, percent elongation, hardness, tear strength, and tear energy of eight plasticized polymers or copolymers, two silicones, and one polyphosphazene fluoroelastomer. Tests were run at 24 hours after specimen preparation and repeated after 900 hours of accelerated aging in a Weather-Ometer device. The data indicated a wide range of physical properties for soft denture-lining materials and showed that accelerated aging dramatically affected the physical and mechanical properties of many of the elastomers. No soft denture liner proved to be superior to all others. The data obtained should provide clinicians with useful information for selecting soft denture lining materials for patients. PMID:8455156
Dootz, E R; Koran, A; Craig, R G
A technique for obtaining maxillomandibular registration for complete denture patients is presented. The maxillary rim is formed with the use of conventional techniques. The mandibular rim is made from modeling plastic impression compound on a record base formed by the patient into the neutral zone. The mandibular rim then is reheated, and the patient determines the occlusal vertical dimension by
Stephen G. Alfano; Richard J. Leupold
Edentulous orodyskinesia (ED) is a neglected source of aimless oral movements that may be confused with tardive dyskinesia (TD). We attempted to clarify the clinical features, significance, and orodental factors in relation to ED. Fourteen ED subjects, 13 TD patients, and 15 age-matched controls self-assessed their oral pain perception, condition, and function using a visual analogue scale. Dyskinesias were classified and rated by a neurologist. Perioral thermal and pressure pain threshold studies, and a standardized orodental examination, were conducted blind to subject group. The perceived oral pain level was low in all groups, and those reporting a significant intensity level of pain (>or=50th percentile) were few. The pain thresholds in both dyskinetic groups were comparable to control values. All ED cases wore a complete set of dentures, considered a current source of problems by 85.7% of them. ED cases commonly displayed inadequate dental occlusal relationship (P = 0.014 vs. controls; P = 0.036 vs. TD) and an overclosed vertical dimension (P = 0.006 vs. controls) as well as unstable and unretentive dentures. ED was limited to the oral region, spared the tongue when the mouth is open, and was never severe in our patients. ED has distinct movement characteristics and is often associated with inadequate dentures and biomechanical sources of denture instability. The contribution of the foregoing findings to the expression of oral dyskinesia warrants further studies. PMID:18759358
Blanchet, Pierre J; Popovici, Romana; Guitard, Francine; Rompré, Pierre H; Lamarche, Claude; Lavigne, Gilles J
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.
Deogade, Suryakant Chhagan
Background. The problems of fungal infections in edentulous have been discussed in literature. Findings show that oral mycosis has an influence on the mycosis of oesophageal mucosa. Based on this we started to follow from 2007 in patients who wear dentures mycological examination, to evaluate changes of yeasts numbers, the sensitivity to antibiotics and determine the impact of types of prosthesis, time of using, gender and age of patients. 1230 patients who were wearing dentures participated in the retrospective study. The material for mycological examination was sampled as a smear from the palate. After the mycological identification of Candida species and assessment of growth, the susceptibility testing with Fluconazole and Nystatin was made. The number of 23 Candida species was diagnosed microbiologically in five years. C. albicans and C. glabrata were increasing in number—from 33,7% to 46,9% and 6,7% to 14,0%, respectively. There was a significant statistical difference between yeasts growth and gender (P = 0, 017 < 0.05). The conclusion is that a large percentage of persons wearing removable denture has been affected by Candida species and that could lead to the mycosis of farther gastrointestinal tract sections. The mycological examination before treatment, especially in patients using acrylic denture, appears to be necessary.
Loster, Bartlomiej W.; Loster, Jolanta; Wieczorek, Aneta; Ryniewicz, Wojciech
The purpose of this paper is to study the effect of methacrylated polyhedralsilsesquioxanes (POSS) on the fracture toughness of poly(methyl methacrylate) (PMMA) based denture?based resins. POSS is a nanostructured material, that is, known to reinforce polymeric systems. Previous work has shown that POSS can improve the mechanical properties of dimethacrylate dental resin systems. Our work shows that there is no
Tamer Hamza; Alvin G. Wee; Satish Alapati; Scott R. Schricker
Statement of problem Acrylic resins are prone to microbial adherence, especially by Candida albicans. Surface-charged resins alter the ionic interaction between the denture resin and Candida hyphae, and these resins are being developed as a means to reduce microbial colonization on the denture surface. Purpose The purpose of this study was to investigate the physical and mechanical properties of phosphate-containing polymethyl methacrylate resins for their suitability as a denture material. Material and methods Using PMMA with cross-linker (Lucitone 199) as a control, 4 experimental groups containing various levels of phosphate with and without cross-linker were generated. The properties examined were impact strength, fracture toughness, wettability (contact angle), and resin bonding ability to denture teeth. Impact strength was tested in the Izod configuration (n=16), and fracture toughness (n=13) was measured using the single-edge notched bend test. Wettability was determined by calculating the contact angle of water on the material surface (n=12), while ISO 1567 was used for bonding ability (n=12). The data were analyzed by 1- and 2-way ANOVA (?=.05). Results A trend of increased hydrophilicity, as indicated by lower contact angle, was observed with increased concentrations of phosphate. With regard to the other properties, no significant differences were found when compared with the control acrylic resin. Conclusions No adverse physical effect due to the addition of a phosphate-containing monomer was found in the acrylic denture resins. Additional mechanical and physical properties, biocompatibility, and clinical efficacy studies are needed to confirm the in vivo anti-Candida activity of these novel resins.
Puri, Gaurav; Berzins, David W.; Dhuru, Virendra B.; Raj, Periathamby A.; Rambhia, Sameer K.; Dhir, Gunjan; Dentino, Andrew R.
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
Background Studies suggest that using a denture/bridge may prevent disability in older people. However, not all older people with few remaining teeth use a denture/bridge. This cross-sectional study aimed to examine the social determinants which promote denture/bridge use among older Japanese. Methods A total of 54,388 (25,630 males and 28,758 females) community-dwelling individuals aged 65 or over, living independently, able to perform daily activities, and with 19 or fewer teeth. The dependent variable was denture/bridge use. Socio-demographics, number of teeth, present illness, social participation, social support, and social networks were used as individual-level independent variables. Data for social capital were aggregated and used as local district (n?=?561 for males, n?=?562 for females) -level independent variables. Number of dentists working in hospitals/clinics per population and population density were used as municipality (n?=?28) -level independent variables. Three-level multilevel Poisson regression analysis was performed for each sex. Results High equivalent income, low number of teeth, present illness, and living in a municipality with high population density were significantly associated with denture/bridge use in both sexes in the fully adjusted models (p?0.05). Denture/bridge use was significantly associated with high educational attainment in males and participating in social groups in females in the fully adjusted model (p?0.05). No significant associations were observed between denture/bridge use and social capital. Conclusions Denture/bridge use was significantly associated with high economic status and present illness in both sexes, high educational attainment in males, and participation in social groups in females among community-dwelling older Japanese after adjusting for possible confounders.
This clinical report describes the treatment of a patient in need of an immediate complete denture who presented with severe erosive lichen planus. In conjunction with an immediate complete denture, tacrolimus (0.1%) ointment, an immunosuppressive agent, was applied topically over the lesions. There was a significant reduction in the size of the lesions at the second week of treatment, allowing the patient to tolerate the prosthesis without pain, thereby improving her quality of life. PMID:17547941
Rabanal, Alejandro; Bral, Michael; Goldstein, Gary
This clinical report describes the treatment of a patient in need of an immediate complete denture who presented with severe erosive lichen planus. In conjunction with an immediate complete denture, tacrolimus (0.1%) ointment, an immunosuppressive agent, was applied topically over the lesions. There was a significant reduction in the size of the lesions at the second week of treatment, allowing the patient to tolerate the prosthesis without pain, thereby improving her quality of life. PMID:17936124
Rabanal, Alejandro; Bral, Michael; Goldstein, Gary
Statement of the problem The effect of long-term water immersion on the shear bond strength between denture base resin and Triad visible-light-polymerized (VLP) direct hard reline resin is not known. Purpose The aim of this study was to investigate the bonding characteristics of Triad VLP direct hard reline resin to heat-polymerized denture base resin subjected to long-term water immersion. Material and methods Ninety circular disks, 15 mm in diameter and 3 mm thick, of denture base resin were polymerized from a gypsum mold. Sixty specimens were subjected to water immersion and 30 were stored at ambient room temperature for 4 months. Thirty water-immersed specimens were dried with gauze (group 1), while the other 30 water-immersed specimens were dried with a hair dryer (group 2). The dry specimens (n = 30) represented the control group (group 3). All specimens were air abraded and painted with bonding agent before packing Triad VLP direct hard-reline resin. Specimens in each group were subjected to thermal cycling for 50,000 cycles between 4 °C and 60 °C water baths with 1-min dwell time at each temperature. The bond strength at which the bond failed under stress was recorded using a universal testing machine. One-way ANOVA and Tukey post hoc comparison were applied to find significant differences between groups (? = 0.05). Results Significant differences in mean shear bond strength among the specimens existed because of variable water content in the denture base resin (P < 0.05). Group 3 (dry) was higher than group 2 (desiccated), and the lowest was group 1 (saturated). Conclusion The shear bond strength of Triad VLP direct hard reline resin to denture base resin depended on the water content in the denture base resin. The dry denture base resin demonstrated superior bond strength compared with the desiccated and water-saturated denture base resins.
Al Rifaiy, Mohammad Q.
Six different cross-linking agents were added to the monomer component of an autopolymerizing denture base resin, and their effects on the water sorption and solubility were investigated. The results of this study suggested that the chemical nature of the polymer versus that of the water molecule directly affected the water sorption of denture base resin. The addition of a cross-linking agent decreased the solubility with increasing concentration. PMID:8814563
Arima, T; Murata, H; Hamada, T
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.
Konchada, Jagadish; Karthigeyan, Suma; Ali, Syed Asharaf; R, Venkateshwaran; Amirisetty, Ramesh; Dani, Anurag
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.
Salloum, Alaa'a M.
Fracture strength of denture base resins is of great concern and many approaches have been made to improve the fracture resistance\\u000a of acrylic resin dentures by strengthening them. Purpose of the study was to assess the effect of a Novel pre-impregnated\\u000a glass fiber reinforcement system and nylon fiber reinforcement on the flexural strength of conventional heat-polymerized poly(methylmethacrylate)\\u000a [PMMA] denture resin
Komal Ladha; Dipti Shah
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.
Sadr, Katayoun; Mahboob, Farhang; Rikhtegar, Elaheh
Role of complete dentures in reducing apnea-hypoapnea index in edentulous obstructive sleep apnea patient has shown promising results in previous studies. This study was undertaken to ascertain the role of complete denture and complete denture with slight increase in vertical dimension using custom made occlussal jig, on retropharyngeal space, posterior airway space, pharyngeal depth, and spirometric readings in comparison with those in edentulous group. Significant changes were observed in both intervention groups and thus, paving the way for doing further research for the consideration of using complete denture with modifications as an oral appliance in edentulous obstructive sleep apnea patient. PMID:21991477
Gupta, Prachi; Thombare, Ram; Pakhan, A J; Singhal, Sameer
Menopause is a normal developmental stage in a woman's life, marking the permanent cessation of menstruation resulting from irreversible changes in the hormonal and reproductive functions of the ovaries and is associated with a large number of symptoms ranging from physical to psychological. Some of the common oral manifestations are oral burning sensation with associated mucosal infections, pain, altered taste perception, and alveolar bone loss. These symptoms may unfavorably affect oral health and treatment needs requiring dentists to devise newer methods that would add along to the treatment modalities advised by gynecologists in relieving menopausal women from above symptoms. The present case report describes an innovative method of fabricating a metal base denture in an edentulous female that would help perimenopausal/menopausal/post-menopausal edentulous women feel hot/cold sensations of food/liquids, thereby giving them relief from pain, better taste perception, and relief from associated allergic and candidal infections that are common with conventional acrylic base dentures. PMID:24082754
Bhatia, Vishwas; Bhatia, Garima; Jain, Nitul; Jadon, Ashwani Kumar
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
Menopause is a normal developmental stage in a woman's life, marking the permanent cessation of menstruation resulting from irreversible changes in the hormonal and reproductive functions of the ovaries and is associated with a large number of symptoms ranging from physical to psychological. Some of the common oral manifestations are oral burning sensation with associated mucosal infections, pain, altered taste perception, and alveolar bone loss. These symptoms may unfavorably affect oral health and treatment needs requiring dentists to devise newer methods that would add along to the treatment modalities advised by gynecologists in relieving menopausal women from above symptoms. The present case report describes an innovative method of fabricating a metal base denture in an edentulous female that would help perimenopausal/menopausal/post-menopausal edentulous women feel hot/cold sensations of food/liquids, thereby giving them relief from pain, better taste perception, and relief from associated allergic and candidal infections that are common with conventional acrylic base dentures.
Bhatia, Vishwas; Bhatia, Garima; Jain, Nitul; Jadon, Ashwani Kumar
The coronomaxillary space defines the distal-most extension of the maxillary denture border, and it usually is tightened during mouth opening. It has been reported that its adequate filling or overfilling is helpful in prosthesis retention. Two types of individual anatomical variations can affect the size of this space: vertical or lateral. With vertical variations, the space increases or does not vary when the mouth is opened; therefore, the prosthesis border must be thicker to obtain adequate retention. With lateral variations, the coronomaxillary space is reduced when the mouth is opened; therefore, the prosthesis border must be thin. The case reports presented here show how complete denture retention can be augmented by the careful recording of the coronomaxillary space dimensions. PMID:22782062
Naveen, Y G; Patel, J R; Sethuraman, Rajesh; Prajapati, Paranjay
Failure of the bond between the acrylic resin and resilient liner material is commonly encountered in clinical practice. The\\u000a purpose of this study was to investigate the effect of different surface treatments (sandblasting, Er:YAG, Nd:YAG, and KTP\\u000a lasers) on tensile bond strength of silicone-based soft denture liner. Polymethyl methacrylate test specimens were fabricated\\u000a and each received one of eight surface
Hakan Akin; Faik Tugut; Burcu Mutaf; Gulsah Akin; A. Kemal Ozdemir
Background and objective Surfaces and fluids can affect oral bacterial colonization. The aim of this study was to compare re-developing biofilms on natural teeth and dentures. Methods Supragingival plaque samples were taken from 55 dentate subjects and the denture teeth of 62 edentulous subjects before and after professional cleaning. Also, samples from 7 “teeth” in randomly selected quadrants were collected after 1, 2, 4 and 7 days of no oral hygiene. Samples were analyzed using checkerboard DNA-DNA hybridization. Counts and proportions of 41 bacterial taxa were determined at each time point and significant differences were sought using the Mann-Whitney test. Ecological succession was determined using a modified moving window analysis. Results Mean total DNA probe counts were similar pre-cleaning but were higher in dentate subjects at all post-cleaning visits (p<0.01). Pre-cleaning edentate biofilms had higher counts and proportions of Streptococcus mitis, Streptococcus oralis and Streptococcus mutans, whereas dentate subjects had higher proportions of Tannerella forsythia, Selenomonas noxia and Neisseria mucosa. By 2 days, mean counts of all taxa were higher in natural teeth and most remained higher at 7 days (p<0.01). Succession was more rapid and complex in dentate subjects. Both groups demonstrated increased proportions of S. mitis and S. oralis by 1 day. N. mucosa, Veillonella parvula and Eikenella corrodens increased in both groups but later in edentate samples. Conclusions “Mature” natural and denture teeth biofilms have similar total numbers of bacteria but different species proportions. Post-cleaning biofilm re-development is more rapid and more complex on natural than denture teeth.
Teles, F.R.; Teles, R.P.; Sachdeo, A.; Uzel, N.G.; Song, X.Q.; Torresyap, G.; Singh, M.; Papas, A.; Haffajee, A.D.; Socransky, S.S.
Gagging is most common protective reflex that prevents the foreign bodies from entering trachea. But some patients have abnormally active gag reflex. The purpose of this paper was to describe method of managing gagging patients , based on modified treatment approaches, starting from impression making to design of the prosthesis i.e. palateless denture, to help the patient tolerate prosthesis in his/her mouth.
Jain, Anoop; V, Vijayalaxmi; Bharathi, R.M.; Patil, Veena; Alur, Jyoti
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
For dento-oral rehabilitation of edentulous (toothless) patients, speech intelligibility is an important criterion. 28 persons\\u000a read a standardized text once with and once without wearing complete dentures. Six experienced raters evaluated the intelligibility\\u000a subjectively on a 5-point scale and the voice on the 4-point Roughness-Breathiness-Hoarseness (RBH) scales. Objective evaluation\\u000a was performed by Support Vector Regression (SVR) on the word accuracy
Tino Haderlein; Tobias Bocklet; Andreas Maier; Elmar Nöth; Christian Knipfer; Florian Stelzle
This study was performed to determine whether some flexural properties of a denture base resin material could be improved\\u000a through reinforcement with five types of aesthetic fibers at 3% concentration by weight and in 2, 4, and 6 mm length. Five\\u000a specimens of similar dimensions were prepared for each of the test groups; base resin and the same resin with glass,
Orhan Murat Do?an; Giray Bolay?r; Selda Keskin; Arife Do?an; Bülent Bek
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. PMID:22734733
Goiato, Marcelo Coelho; Ribeiro, Paula do Prado; Pellizzer, Eduardo Piza; Pesqueira, Aldiéris Alves; Haddad, Marcela Filiè; dos Santos, Daniela Micheline; Moreno, Amália
The purpose of this study was to evaluate the effect of denture cleansers on the surface roughness, hardness and color stability of two polyamides (Valpast, Deflex), a butadiene styrene copolymer PMMA (Rodex), and PMMA polymer as a control group (Paladent). Each material was divided into 5 sub-groups (n=7) as two control and three test groups. Three test groups were immersed for 20 days in commercially available three denture cleansers (CO-Corega, PR-Protefix, VA-Valclean). Two-way analysis of variance and Tukey's post hoc HSD test were used to evaluate surface roughness and hardness data (?=0.05). ?E, ?L*, ?a*and ?b* mean values were used for ANOVA, Tamhane test was used as post hoc. Polyamides showed low hardness and high roughness before and after immersion. A significant decrease in hardness was observed for all resins except Rodex after immersion (p<0.05). The denture cleansers changed the roughness, hardness and color of some resins. PMID:23718995
Durkan, Rukiye; Ayaz, Elif Aydo?an; Bagis, Bora; Gurbuz, Ayhan; Ozturk, Nilgun; Korkmaz, Fatih Mehmet
Posterior denture teeth wear faster than the anterior teeth, causing occlusal prematurities and loss of vertical dimension of occlusion. The loss of vertical dimension of occlusion lays more stress on the anterior alveolar ridge, which in turn increases the rate of residual ridge resorption and causes loss of alveolar ridge height in the anterior segment and compromises esthetics. Hence it is important for the clinician to choose acrylic resin teeth with high wear resistance. The objective of the study is to investigate and compare the wear resistance of three different commercially available acrylic resin denture teeth. 60 specimens were tested for wear resistance in terms of loss of weight and loss in volume on a wear and friction monitor for 5,000 cycle wear periods (total of 10,000 cycles) under a 0.20 kg load. Statistical analysis used: The findings were analyzed using one way analysis of variance (ANOVA) and Tukey HSD test. Comparison of weight loss and volume loss between Surana ultradent, Premadent and Dentek showed highly significant difference, Surana ultraddent having better wear resistance. Surana ultradent acrylic resin denture had highest wear resistance amongst the three groups of tested samples. PMID:21886405
Shetty, Mallika S; Shenoy, K Kamalakanth
The purpose of this study was to evaluate the hardness and energy absorption properties of four commercially available chairside silicone denture soft lining materials and to compare their properties with those of a heat-polymerized silicone denture liner. The denture lining materials investigated were four auto-polymerising silicone soft liners (GC Reline Soft, Ufigel SC, Elite Soft Relining and Tokuyama Sofreliner S) and a heat-polymerised silicone liner (Molloplast B). The soft liners were processed according to manufacturers' instructions. The specimens for hardness testing were 38 x 38 x 3 mm. The specimens for energy absorption test were 10 x 10 x 3 mm. In each test ten samples of each material were tested. There was strong evidence that Tokuyama Sofreliner S and, to a lesser extent, Ufigel SC, were less stiff and more resilient than Molloplast B. There was also strong evidence that both GC Reline Soft and Elite Soft Relining were harder than Molloplast B, while Ufigel SC and Tokuyama Sofreliner S were softer In conclusion differences existed between hardness and energy absorption properties of the soft lining materials. PMID:21265439
Tasopoulos, Theodorus; Jagger, Robert G; Jagger, Daryll C; Griffiths, Alex E
This study examined the adaptation accuracy of acrylic denture base processed using fluid-resin (PERform), injection-moldings (SR-Ivocap, Success, Mak Press), and two compression-molding techniques. The adaptation accuracy was measured primarily by the posterior border gaps at the mid-palatal area using a microscope and subsequently by weighing of the weight of the impression material between the denture base and master cast using hand-mixed and automixed silicone. The correlation between the data measured using these two test methods was examined. The PERform and Mak Press produced significantly smaller maximum palatal gap dimensions than the other groups (p<0.05). Mak Press also showed a significantly smaller weight of automixed silicone material than the other groups (p<0.05), while SR-Ivocap and Success showed similar adaptation accuracy to the compression-molding denture. The correlationship between the magnitude of the posterior border gap and the weight of the silicone impression materials was affected by either the material or mixing variables. PMID:20675954
Lee, Chung-Jae; Bok, Sung-Bem; Bae, Ji-Young; Lee, Hae-Hyoung
The purpose of the current study was to investigate the effect of a chemical disinfectant (sodium hypochlorite 5.25 %) on color stability of a denture base acrylic resin and two processed soft denture lining materials of two different types (acrylic-based and silicone-based). Ten specimens from each type of materials tested were made (2 × 20 × 20 mm). All specimens were immersed in sodium hypochlorite (5.25 %). Colorimetric measurements for each specimen were taken before immersion, and after 24 h and 7 days of immersion. Color changes were evaluated using the CIE L*a*b* colorimetric system. Data were statistically analyzed with one-way analysis of variance (ANOVA) (? = 0.05). ANOVA was followed by Bonferroni test to determine which groups differed from each other. ?E and ?L* of the silicone-based liner at the 1st and 7th days of immersion were significantly more than of denture base acrylic resin and acrylic-based liner. Change in ?L* values of denture base acrylic resin and acrylic-based liner was small and statistically insignificant after 24 h of its immersion. However, the increase in ?L* values of the acrylic-based liner after 7 days of immersion was considerably more than of denture base acrylic resin. Color changes in denture base acrylic resin and soft denture liners tended to increase with longer immersion times, and the color stability of the soft denture liners was influenced by its chemical type. PMID:24757356
Salloum, Alaa'a M
The denture base which is made from the acrylic resin often occurs the fracture during function, and it is known that this fracture is mainly occured by the fatigue fracture, which is happened by the crack growth from the location of high stress. Until now, the author discussed on the fatigue properties about the specimens with semi-circular notch as the model of the remaining natural teeth, but these results are not easily applied to the design of denture base because the shape of denture base, considering its function and esthetics, is not changed. So, for the improvement of the strength of denture base, the denture base might be used the reinforcement. And, used as a trial the organic fiber as reinforcement, and their effects were investigated from the sides of the bending moment at fracture and the strain distribution occurs the fracture at the posterios palatal area, and its strength is improved 190%. And the fracture of the complete denture happens in general at the location between two central incisors, therefore this problem should be considered as the notched effect. So, reinforcing the lingual part of maxillary anterior teeth using the organic fiber, its strength is improved 53% comparing with the general complete denture. Therefore, the effects of reinforcement were enough appeared, and the improvement of the strength of denture base is very expected in dental use. PMID:1066409
Although many factors that generate changes in OVD of complete dentures are known, no information is available in the dental literature regarding the effect of using high expansion dental stone (type V) on changes in OVD. This study therefore investigated the effect of a high expansion dental stone on the changes in OVD of complete dentures. A compression moulding technique was used to process twenty sets of simulated upper and lower dentures. Sample was equally divided into two groups: group of type III dental stone (DST III), and group of type V dental stone (DST V). In DST III, the lower, middle and upper parts of flask were filled with type III dental stone; In DST V, the procedure was the same as DST III except for the middle layer that was made of type V high expansion dental stone. Changes in OVD were measured before and after denture processing. A Shapiro-Wilk Normality Test was applied, and then collected data were analysed with t-test statistics for statistically significant differences at the 95% confidence level. The two groups revealed small but statistically significant increase in OVD as a result of processing. The increase in OVD was significantly less in DST V than in DST III. The use of high expansion dental stone can be recommended as investing material to reduce the increase in OVD that occurs after processing complete dentures. PMID:24479215
Salloum, A M
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
Polymerization shrinkage is one of the major drawbacks of the acrylic resin. The present study was conducted to evaluate the dimensional changes occurring in the dentures, constructed on the casts having different configurations of the palatal vault, during processing and the effect of water sorption on the processed dentures. Eight maxillary edentulous casts having U, F and V configurations of palatal vault were selected and complete dentures were fabricated. Dimensional changes occurring in the processed dentures were studied in different regions during processing as well as after water sorption. It was observed that dimensional changes in frontal and vertical planes were maximum in V shaped palatal vault dentures. Water sorption partly compensated for the dimensional changes that occurred during processing. PMID:15751783
Hegde, Veena; Patil, Narendra
Introduction About 3% of people will be diagnosed with epilepsy during their lifetime, but about 70% of people with epilepsy eventually go into remission. Methods and outcomes We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of starting antiepileptic drug treatment following a single seizure? What are the effects of drug monotherapy in people with partial epilepsy? What are the effects of additional drug treatments in people with drug-resistant partial epilepsy? What is the risk of relapse in people in remission when withdrawing antiepileptic drugs? What are the effects of behavioural and psychological treatments for people with epilepsy? What are the effects of surgery in people with drug-resistant temporal lobe epilepsy? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically; please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). Results We found 83 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions. Conclusions In this systematic review we present information relating to the effectiveness and safety of the following interventions: antiepileptic drugs after a single seizure; monotherapy for partial epilepsy using carbamazepine, gabapentin, lamotrigine, levetiracetam, phenobarbital, phenytoin, sodium valproate, or topiramate; addition of second-line drugs for drug-resistant partial epilepsy (allopurinol, eslicarbazepine, gabapentin, lacosamide, lamotrigine, levetiracetam, losigamone, oxcarbazepine, retigabine, tiagabine, topiramate, vigabatrin, or zonisamide); antiepileptic drug withdrawal for people with partial or generalised epilepsy who are in remission; behavioural and psychological treatments for partial or generalised epilepsy (biofeedback, cognitive behavioural therapy (CBT), educational programmes, family counselling, relaxation therapy (alone or plus behavioural modification therapy, yoga); and surgery for drug-resistant temporal lobe epilepsy ( lesionectomy, temporal lobectomy, vagus nerve stimulation as adjunctive therapy).
The prevalence of abnormal (retracted) position of the tongue at rest was examined in subjects with varying number of natural lower teeth. The aim of the study was to explore the relationship between tongue retraction and state of dentition and to identify potentially related parameters. The resting tongue positions were recorded in subjects partially edentulous in the lower jaw (n = 164) and compared with those met in dentate (n = 57) and completely edentulous participants (n = 84). Potentially related parameters, such as age, sex, duration of edentulism, palate vault and signs of temporomandibular disorders were also recorded. Tongue retraction was observed in a small percentage (12.3%) of the dentate, almost half (45.7%) of the partially edentulous and in the majority (67.8%) of the completely edentulous participants. The number of natural lower teeth correlated with the resting tongue position in the partially edentulous group. The tongue position at rest was also found weakly related to signs of temporomandibular disorders in the dentate group and to the sex and duration of edentulism in the partially edentulous group. It was concluded that the abnormal positioning of the resting tongue is increasingly observed with decreasing number of natural teeth, possibly in accordance with the morphological and functional alterations that result from teeth loss. The presence of a retracted tongue affects the complete denture construction; however, its effect on denture function remains questionable. PMID:15899017
Kotsiomiti, E; Farmakis, N; Kapari, D
The purpose of this study was to clarify quantitatively the differences in tongue-tip motion among the dentulous elderly people and also among the elderly edentulous, both with and without their dentures and, to identify the influence of tooth loss and denture wear on tongue-tip motion. Fourteen young dentulous people, 12 elderly dentulous people and 13 elderly edentulous people participated in this study. Subjects were asked to swallow a 10 mL barium sulfate solution three times. The elderly edentulous people were asked to swallow the solution while wearing dentures and with dentures removed. Functional swallowing was recorded on cine-film with a digital subtraction angiography system. Lateral cinefluorography images were obtained from seated subjects. Using a cine-projector, the movements of the tongue surface were traced as dots and lines frame by frame on a single tracing sheet within a definite period of time from the beginning of the oral phase to the end of the pharyngeal phase. With counting the number of 'trajectories' of tongue-tip motion, tongue movements were classified as 'stable' and 'hyperactive' types. The results was that significantly more 'hyperactive' type subjects were found among the elderly edentulous who were not wearing dentures (12 of 13) compared with the dentulous young (1 of 14), the elderly dentulous (1 of 13) or the elderly edentulous wearing dentures (1 of 13) (P < 0.001). The tongue-tip motion for the 'hyperactive' type was very complex and the tongue-tip anchoring against the palate was always instable. PMID:19090906
Yoshikawa, M; Yoshida, M; Nagasaki, T; Tanimoto, K; Tsuga, K; Akagawa, Y
The rehabilitation of patients following maxillary & mandibular resection is challenging. A prosthesis supported with dental implants is often the treatment of choice, but implants cannot be used predictably in all clinical situations. A tissue supported post resection denture is usually the most acceptable treatment option left in these situations. This case report describes management of a patient who had undergone segmental mandibulectomy & subsequently rehabilitated with resection denture prosthesis. Conventional treatment planning was modified at various stages of fabrication to improve the quality of the final prosthesis. PMID:22645804
Shukla, P; Hegde, C; Rampal, N; Pawah, Salil; Gupta, A; Shukla, M
PURPOSE Polymethyl methacrylate (PMMA) is the most commonly used denture base material despite typically low in strength. The purpose of this study was to improve the physical properties of the PMMA based denture base resins (QC-20, Dentsply Ltd., Addlestone, UK; Stellon, AD International Ltd, Dentsply, Switzerland; Acron MC; GC Lab Technologies Inc., Alsip, Japan) by copolymerization mechanism. MATERIALS AND METHODS Control group specimens were prepared according to the manufacturer recommendations. In the copolymer groups; resins were prepared with 5%, 10%, 15% and 20% acrylamide (AAm) (Merck, Hohenbrunn, Germany) content according to the moleculer weight ratio, respectively. Chemical structure was characterized by a Bruker Vertex-70 Fourier transform infrared spectroscopy (FTIR) (Bruker Optics Inc., Ettlingen, Germany). Hardness was determined using an universal hardness tester (Struers Duramin, Struers A/S, Ballerup, Denmark) equipped with a Vickers diamond penetrator. The glass transition temperature (Tg) of control and copolymers were evaluated by Perkin Elmer Diamond DSC (Perkin Elmer, Massachusetts,USA). Statistical analyses were carried out using the statistical package SPSS for Windows, version 15.0 (SPSS, Chicago, IL, USA). The results were tested regarding the normality of distribution with the Shapiro Wilk test. Data were analyzed using ANOVA with post-hoc Tukey test (P<.01). RESULTS The copolymer synthesis was confirmed by FTIR spectroscopy. Glass transition temperature of the copolymer groups were higher than the control groups of the resins. The 10%, 15% and 20% copolymer groups of Stellon presented significantly higher than the control group in terms of hardness. 15% and 20% copolymer groups of Acron MC showed significantly higher hardness values when compared to the control group of the resin. Acrylamide addition did not affect the hardness of the QC-20 resin significantly. CONCLUSION Within the limitation of this study, it can be concluded that copolymerization of PMMA with AAm increased the hardness value and glass transition temperature of PMMA denture base resins.
Durkan, Rukiye; Bagis, Bora
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.
Landayan, Jordi Izzard Andaya; Manaloto, Adrian Carlos Francisco; Shin, Sang-Wan
Restoring the edentulous mandible with a removable prosthesis can be a challenging prospect for both the dentist and patient during and after treatment. Poor retention and support are the major problems reported with a mandibular complete denture and these can be significantly improved with the use of implants and retentive attachments. Utilizing implants requires careful planning from both the surgical and restorative aspects to ensure that the intended treatment aim and outcome is achieved. Clinical Relevance: This case highlights the importance of both restorative and surgical considerations when planning the rehabilitation of the mandible with dental implants. PMID:24783882
Patel, Upen; Walmsley, Damien
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
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?0.01). However, after 48 h, both CT groups (CT5 and CT8) showed biofilm recolonization (p?0.01). Residual biofilm recolonization was also detected by CLSM and SEM analysis, which revealed a higher biomass and average biofilm thickness for the CT8 group (p?0.01). Conclusion Citric acid denture cleansers can reduce C. albicans biofilm accumulation and cell viability. However, this CT did not prevent biofilm recolonization.
Presurgical prosthetic treatment planning is critical for the success of the implant prosthesis. Inadequate treatment plan, due to insufficient discussion between prosthodontist, and surgeon, may result in poor prognosis. A 26-year-old male patient was referred for prosthodontic treatment after implant was placed in the area of teeth #17, 16, 22, 25 and 27, without adequate discussion nor the treatment planning between oral surgeon and prosthodontist. It was found that the patient had two hopeless teeth, and a severely resorbed alveolar ridge. Additional tooth extraction was needed and the type of definitive prosthesis was shifted from fixed type to removable one. Proper pre-surgical treatment planning is essential for the good prognosis. Implant-supported removable prosthesis on milled bars may be a useful treatment option in patients with incorrect angled placement on severely resorbed alveolar ridge.
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.
Mitrea, Alexandru I.; Badea, Iulia Clara; Chifor, Radu; Badea, Mindra Eugenia; Mitrea, Paulina; Popa, Sever; Crisan, Maria; Avram, Ramona
The effect of Candida albicans biofilms and methyl methacrylate (MMA) pretreatment on the bond strength between soft denture liners and polymethyl methacrylate (PMMA) resin was analyzed. Specimens were prepared and randomly divided with respect to PMMA pretreatment, soft liner type (silicone-based or PMMA-based), and presence or absence of a C. albicans biofilm. Samples were composed of a soft denture liner bonded between two PMMA bars. Specimens (n = 10) were incubated to produce a C. albicans biofilm or stored in sterile PBS for 12 days. The tensile bond strength test was performed and failure type was determined using a stereomicroscope. Surface roughness (SR) and scanning electron microscopy (SEM) analysis were performed on denture liners (n = 8). Highest bond strength was observed in samples containing a silicone-based soft liner and stored in PBS, regardless of pretreatment (p < 0.01). Silicone-based specimens mostly underwent adhesive failures, while samples containing PMMA-based liners predominantly underwent cohesive failures. The silicone-based specimens SR decreased after 12 days of biofilm accumulation or PBS storage, while the SR of PMMA-based soft liners increased (p < 0.01). The PMMA-based soft liners surfaces presented sharp valleys and depressions, while silicone-based specimens surfaces exhibited more gentle features. In vitro exposure to C. albicans biofilms reduced the adhesion of denture liners to PMMA resin, and MMA pretreatment is recommended during relining procedures. PMID:25000598
Mendonça e Bertolini, Martinna de; Cavalcanti, Yuri Wanderley; Bordin, Dimorvan; Silva, Wander José da; Cury, Altair Antoninha Del Bel
The effects of four liquid components of denture acrylic resin on host cell activity and fungal adhesion were investigated in this study. The low concentration (1 micromol l(-1)) of the liquid components caused no change in the activities and morphologies of the gingival fibroblast cells, compared with control and dimethylsulphoxide-exposed cells. However, when the cells were exposed to high concentrations (1 mmol l(-1)) of benzqyl peroxide, morphological change was observed, implying that the exposure of the cells to high concentrations of the liquid components of denture acrylic causes the loss of adhesion proteins from the cells. Thus the amount of Candida adhesion to human gingival cells was analysed, and the adherence of fungi to the cell was significantly reduced when the cells were pre-exposed to methyl methacrylate, hydroquinone and benzoyl peroxide at a concentration of 1 micromol l(-1) (P < 0.01), which did not affect either the cell viability or the cell morphology. These results, taken together, suggested that the renewal of dentures could be a possible therapeutic and/or preventive aid for oral candidosis in denture-wearing patients. PMID:12572719
Makihira, S; Nikawa, H; Nishimura, M; Egusa, H; Sadamori, S; Rahayu, R P; Nishimura, H; Hamada, T
The effect of Candida albicans biofilms and methyl methacrylate (MMA) pretreatment on the bond strength between soft denture liners and polymethyl methacrylate (PMMA) resin was analyzed. Specimens were prepared and randomly divided with respect to PMMA pretreatment, soft liner type (silicone-based or PMMA-based), and presence or absence of a C. albicans biofilm. Samples were composed of a soft denture liner bonded between two PMMA bars. Specimens (n = 10) were incubated to produce a C. albicans biofilm or stored in sterile PBS for 12 days. The tensile bond strength test was performed and failure type was determined using a stereomicroscope. Surface roughness (SR) and scanning electron microscopy (SEM) analysis were performed on denture liners (n = 8). Highest bond strength was observed in samples containing a silicone-based soft liner and stored in PBS, regardless of pretreatment (p < 0.01). Silicone-based specimens mostly underwent adhesive failures, while samples containing PMMA-based liners predominantly underwent cohesive failures. The silicone-based specimens SR decreased after 12 days of biofilm accumulation or PBS storage, while the SR of PMMA-based soft liners increased (p < 0.01). The PMMA-based soft liners surfaces presented sharp valleys and depressions, while silicone-based specimens surfaces exhibited more gentle features. In vitro exposure to C. albicans biofilms reduced the adhesion of denture liners to PMMA resin, and MMA pretreatment is recommended during relining procedures. PMID:24964215
Bertolini, Martinna de Mendonça E; Cavalcanti, Yuri Wanderley; Bordin, Dimorvan; Silva, Wander José da; Del Bel Cury, Altair Antoninha
Aim: The aim of the study was to determine the clinical and histopathological effect on palatal hyperplasia caused by suction cups by different methods of management used for recovery of abused tissues. Materials and Methods: A total of 35 subjects agreed for biopsy procedure, from 50 patients who gave consent for the study. Out of the 35 subjects, 20 were randomly selected for treatment with discontinuation of denture (Group I) and 15 selected for denture relined with tissue conditioner (COE-comfort) (Group II). Punch biopsy procedure was performed on these patients to study the histopathology of the lesion before the two modalities of treatment was administered on them. Results: Inflammation caused by suction cup decreased considerably by both the treatment modalities, i.e., the use of tissue conditioner as well as discontinuation of denture (tissue rest) for a period of 2 weeks. Conclusion: It was concluded that wearing denture day and night considerably increased the severity of inflammatory papillary hyperplasia of palate. Healing was better with tissue conditioner when compared with tissue rest.
Rao, Yogesh; D'souza, Mariette; Porwal, Amit; Yadav, Pankaj; Kumar, Sheetal; Aggarwal, Amit
Purpose: To compare the flexural, tensile and compressive strengths of three denture base materials, namely, Lucitone 550, Bio Carbo Resin, and Eclipse. Materials and Methods: A total of 180 specimens were prepared, with 60 specimens of each material tested. The dimensions of the specimens for each test were made according to the ADA specification. They were stored in distilled water bath at 37°C for 48 hours before testing. Each specimen was fixed on the table of the Instron universal testing machine. A force was applied at a cross-head speed of 5 mm/min until fracture occurred. Data were analyzed using a one-way analysis of variance (ANOVA) and Tukey's test (p=0.05) for the flexural, tensile, and compressive strengths among all groups. Results: The flexural and compressive strength values showed significant differences between the three denture base materials. However, there was no significant difference in tensile strength between Lucitone 550 and Bio CarboResin. Conclusion: Eclipse showed significantly higher mechanical properties than polycarbonate reinforced and conventional heat cured acrylic resins, which suggests the use of Eclipse denture base materials as an alternative to traditional denture base resins. PMID:24984639
Hashem, Mohamed; Alsaleem, Samah O; Assery, Mansour K; Abdeslam, Emad Braka; Vellappally, Sajith; Sukumaran, Anil
The aim of this study was to compare the stress distribution induced by posterior functional loads on conventional complete dentures and implant-retained overdentures with different attachment systems using a two-dimentional Finite Element Analysis (FEA-2D). Three models representative of edentulous mandible were constructed on AutoCAD software; Group A (control), a model of edentulous mandible supporting a complete denture; Group B, a model of edentulous mandible supporting an overdenture over two splinted implants connected with the bar-clip system; Group C, a model of edentulous mandible supporting an overdenture over two unsplinted implants with the O-ring system. Evaluation was conducted on Ansys software, with a vertical force of 100 N applied on the mandibular left first molar. When the stress was evaluated in supporting tissues, groups B (51.0 MPa) and C (52.6 MPa) demonstrated higher stress values than group A (10.1 MPa). Within the limits of this study, it may be concluded that the use of an attachment system increased stress values; furthermore, the use of splinted implants associated with the bar-clip attachment system favoured a lower stress distribution over the supporting tissue than the unsplinted implants with an O-ring abutment to retain the mandibular overdenture. PMID:18482352
Assunção, W G; Tabata, L F; Barão, V A R; Rocha, E P
This finite element analysis compared stress distribution on complete dentures and implant-retained overdentures with different attachment systems. Four models of edentulous mandible were constructed: group A (control), complete denture; group B, overdenture retained by 2 splinted implants with bar-clip system; group C, overdenture retained by 2 unsplinted implants with o'ring system; and group D, overdenture retained by 2 splinted implants with bar-clip and 2 distally placed o'ring system. Evaluation was performed on Ansys software, with 100-N vertical load applied on central incisive teeth. The lowest maximum general stress value (in megapascal) was observed in group A (64.305) followed by groups C (119.006), D (258.650), and B (349.873). The same trend occurred in supporting tissues with the highest stress value for cortical bone. Unsplinted implants associated with the o'ring attachment system showed the lowest maximum stress values among all overdenture groups. Furthermore, o'ring system also improved stress distribution when associated with bar-clip system. PMID:19553853
Barão, Valentim Adelino Ricardo; Assunção, Wirley Gonçalves; Tabata, Lucas Fernando; Delben, Juliana Aparecida; Gomes, Erica Alves; de Sousa, Edson Antonio Capello; Rocha, Eduardo Passos
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.
SILVA, Cintia de Souza; MACHADO, Ana Lucia; CHAVES, Carolina de Andrade Lima; PAVARINA, Ana Claudia; VERGANI, Carlos Eduardo
The flasking and polymerization technique for resins can introduce stresses during processing which may lead to denture base distortions, artificial teeth displacement and increases in the occlusal vertical dimension (OVD). This study investigated whether the association of microwave heat-activation (MH) and bimaxillary flasking (BF) minimizes the possible increases in OVD after prostheses processing. Forty pairs of complete dentures were waxed with the artificial teeth in closed occlusion and divided into four groups according to investing and heating methods: G1 (control) = monomaxillary/water bath; G2 = monomaxillary/microwave; G3 = bimaxillary/water bath and G4 = bimaxillary/microwave. OVD was measured using a digital caliper before and after prostheses processing. Results were submitted to statistical analysis (Student's t-test for multiple comparisons and post hoc ANOVA, alpha = 0.05). Comparison of values before and after processing showed that OVD increased in all groups after polymerization (p < 0.001), regardless of flasking and polymerization methods. Statistically, G2 had the greatest difference in OVD when compared to G1 (p = 0.014), G3 (p = 0.019) and G4 (p = 0.024). G3 and G4 showed similar results statistically when compared to G1 (control). Both investing and heating methods resulted in an increase in OVD after processing. However, the prostheses invested in bimaxillary flasks showed the lowest changes in OVD, regardless of the polymerization method. PMID:23798079
Silva-Concílio, Lais R; Meloto, Carolina B; Neves, Ana Christina C; Cunha, Leonardo G; Rizzatti-Barbosa, Célia M
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.
Cilingir, Altug; Bilhan, Hakan; Sulun, Tonguc; Bozdag, Ergun; Sunbuloglu, Emin
Purpose – The purpose of this paper is to investigate the effects of nano-titanium dioxide and nano-silicon dioxide particles on the mechanical and antimicrobial properties of denture base resin. Design\\/methodology\\/approach – Nano-titanium dioxide and nano-silicon dioxide particles were introduced to heat-curing denture base resin to prepare composites. Electronic universal testing machine and friction tester were used to test tensile strength
Rong Song; Xiaohui Jiao; Long Lin
The denture bases made by using polymethyl methacrylates of Acrylic resin family have excellent physical properties, simple to process and easy to reline, rebase and repair. One of the inherent disadvantages of this material is the liability to break during function. The strength assessment of acrylic resins have been made generally by transverse defection tests. Aim: To evaluate the impact strength valves of certain brands of commercially available denture base resins and suggest their suitability. Materials and methods: The denture bases we made using polymethyl methacrylates of acrylic resin family because they have excellent physical properties, simple to process and easy to reline and rebase. Six commercial brands of polymethyl meth- acrylate, namely Stellon (DPI-India), Acralyn-H (Asian Acrylate, India), Trevalon (Dentsply-England), Lucitone 199 (Dentsply/ York division), Acralyn-H (Super Unbreakable), Trevalon HI (Dentsply, Detray division, England) were tested by breaking them using Analog Pendulum (ASTM D 256). Results: From the entire study the maximum impact strength was reported for Acralyn-H super unbreakable (Asian Acrylates, India) 62.19 joules. Conclusion: All the analysis led to conclusion that there is basic change in material composition within and among the different groups of denture base resins. Clinical implications: The complete dentures made using denture base resins with high impact strength valves (e.g. Acralyn-H super unbreakable) will be more durable and can be used by the patient for considerable period of time, i.e. beyond 4 to 5 years. Keywords: Denture base resins, Impact strength, Unbreakable. How to cite this article: Narendra R, Reddy NS, Reddy SD, Purna CRS, Shekar MC, Balasubramanyam S. A Comparative Evaluation of Impact Strength of Conventionally Heat Cured and High Impact Heat Cured Polymethyl Metharylate Denture Base Resins: An in vitro Study. J Contemp Dent Pract 2013;14(6): 1115-1121. Source of support: Nil Confict of interest: None. PMID:24858761
Narendra, R; Reddy, N Simhachalam; Reddy, Sashi Deepth; Purna, Cr Sashi; Shekar, M Chandra; Balasubramanyam, S
This study was performed to determine whether some flexural properties of a denture base resin material could be improved through reinforcement with five types of aesthetic fibers at 3% concentration by weight and in 2, 4, and 6 mm length. Five specimens of similar dimensions were prepared for each of the test groups; base resin and the same resin with glass, rayon, polyester, nylon 6 and nylon 6,6 fibers in three different lengths. Flexural properties were evaluated by using a 3-point bending test. A visual examination was also made to determine mode of fracture of the specimens. The incorporation of different fibers in varying lengths had no significant effect on flexural strength of the resin. The specimens reinforced with nylon 6,6 fibers of 6 mm length showed the highest flexural strength. Young's modulus and maximum load suggests that such reinforcement makes resin resistant to fracture. PMID:18157685
Do?an, Orhan Murat; Bolayir, Giray; Keskin, Selda; Do?an, Arife; Bek, Bülent
Forty-one complete mandibular subperiosteal implant-supported and retained dentures were consecutively inserted between 1952 and 1971, and patients were monitored through 1992. After variables and methods of follow-up were described, the implants were divided into three categories: 14 (34%) nonfunctional implants, 9 (22%) functioning implants, and 18 (44%) functional implants prematurely terminated by death or cause unrelated to implant condition. Five percent of the implants failed by 5 years, 22% failed by 10 years, 34% failed by 20 years, and none failed after 20 years. Nine implants were still functioning 21 to 36 years after insertion, of which five were functioning for more than 30 years. The implants that were developed later were notably superior to earlier implants. The results of this review could be interpreted to suggest consideration of mandibular subperiosteal implants for selected patients, particularly those with resorbed mandibles. PMID:8850449
Bodine, R L; Yanase, R T; Bodine, A
Background: The purpose of this study was to evaluate the release of chlorhexidine as an antifungal drug from doped self-cured poly (methyl methacrylate) (PMMA) acrylic resin and the effect of the drug released on the growth of Candida albicans. Methods: Release of chlorhexidine was evaluated using liquid chromatography, and the effect of the drug on the growth of C. albicans was investigated microbiologically using a “well” technique on Saboraud culture medium inoculated with a resistant strain of C. albicans. Results: Chlorhexidine leached steadily out of the acrylic resin into distilled water at mouth temperature, and the sustained drug release continued throughout the 28-day test period. The drug released also demonstrated antifungal activity against the resistant strain of C. albicans. Conclusion: The findings of this study support the use of chlorhexidine-impregnated self-cured PMMA chair-side resin as a new dosage form for the treatment of denture-induced stomatitis.
Ryalat, Soukaina; Darwish, Rula; Amin, Wala
Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Poly (methylmethacrylate) (PMMA)/montmorillonite (MMT) nanocomposites were prepared by in situ suspension polymerization with dodecylamine used as MMT-modifier. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were used to characterize the structures of the nanocomposites. Cytotoxicity test, hemolysis test, acute systemic toxicity test, oral mucous membrane irritation test, guinea-pig maximization test and mouse bone-marrow micronucleus test were used to evaluate the biocompatibility of PMMA/MMT nanocomposites. The results indicated that an exfoliated nanocomposite was achieved, and the resulting nanocomposites exhibited excellent biocompatibility as denture base material and had potential application in dental materials. PMID:21373810
Zheng, Junping; Su, Qiang; Wang, Chen; Cheng, Gang; Zhu, Ran; Shi, Jin; Yao, Kangde
The aim of this study was to evaluate the effect of thermocycling and immersion in mouthwash or beverage solutions on the color stability of four different acrylic resin-based dentures (Onda Cryl, OC; QC20, QC; Classico, CL; and Lucitone, LU). The factors evaluated were type of acrylic resin, immersion time, and solution (mouthwash or beverage). A total of 224 denture samples were fabricated. For each type of resin, eight samples were immersed in mouthwashes (Plax-Colgate, PC; Listerine, LI; and Oral-B, OB), beverages (coffee, CP; cola, C; and wine, W), and artificial saliva (AS; control). The color change (DE) was evaluated before (baseline) and after thermocycling (T1), and after immersion in solution for 1 h (T2), 3 h (T3), 24 h (T4), 48 h (T5), and 96 h (T6). The CIE Lab system was used to determine the color changes. The thermocycling test was performed for 5000 cycles. Data were submitted to three-way repeated-measures analysis of variance and Tukey's test (p<0.05). When the samples were immersed in each mouthwash, all assessed factors, associated or not, significantly influenced the color change values, except there was no association between the mouthwash and acrylic resin. Similarly, when the samples were immersed in each beverage, all studied factors influenced the color change values. In general, regardless of the solution, LU exhibited the greatest DE values in the period from T1 to T5; and QC presented the greatest DE values at T6. Thus, thermocycling and immersion in the various solutions influenced the color stability of acrylic resins and QC showed the greatest color alteration. PMID:24878668
Goiato, Marcelo Coelho; Nóbrega, Adhara Smith; dos Santos, Daniela Micheline; Andreotti, Agda Marobo; Moreno, Amália
The aim of this in-vivo study was to evaluate the temperature rise during polymerization of five chairside self-cured hard denture base reliners. For the same patient, 30 identical baseplates, exposing a space on their tissue surface to accommodate the lining material, were made of a light-cured denture base material. A hole was drilled in the center of this area to enable the thermocouple wire of the temperature measuring device to have direct access to the palatal surface of the baseplate. Six baseplates were used for each of the five lining materials tested. Temperature recordings were made every 15 seconds. Data were analyzed using single factor analysis of variance (ANOVA) and the Scheffe's post-hoc analysis for multiple comparisons. The mean maximum temperature values ranged from 40.2 degrees C to 45.7 degrees C being statistically different among the materials (P<0.001). The maximum peak temperature was 53 degrees C and the lowest 39 degrees C. Also the difference between the time each material reached the peak of temperature was statistically significant (P<0.0001). A temperature range of 5.5 degrees C was demonstrated among materials, with the highest polymerization temperatures recorded for Flexacryl Hard and the lowest for Rebase and GC Reline hard. Ufi-gel hard showed the fastest polymerization cycle and was the first to reach the maximum temperature. The available chairside hard liners must be chosen with care considering the thermal effect on the oral mucosa and the discomfort of patient. PMID:20698423
Yannikakis, Stavros; Polychronakis, Nick; Zissis, Alcibiades
The purpose of this study was to investigate whether dietary carbohydrates can modulate the development of Candida albicans biofilms on the denture material surface. Poly (methyl methacrylate) acrylic resin discs were fabricated and had their surface roughness measured. Biofilms of C. albicans ATCC 90028 were developed on saliva-coated specimens in culture medium without (control) or with carbohydrate supplementation by starch, starch+sucrose, glucose, or sucrose for 72 h. The cell count, metabolic activity, biovolume, average thickness, and roughness coefficient were evaluated at the adhesion phase (1.5 h) and after 24, 48, and 72 h. The secretion of proteinases and phospholipases, cell surface energy, and production of extra/intracellular polysaccharides were analyzed after 72 h of biofilm development. Data were analyzed by one- and two-way ANOVA followed by Tukey’s test at 5% significance level. In the early stages of colonization (adhesion and 24 h), the glucose group showed the highest cell counts and metabolic activity among the groups (p<0.05). After maturation (48 and 72 h), biofilms exposed to glucose, sucrose, or starch+sucrose showed higher cell counts and metabolic activity than the control and starch groups (p<0.001). Compared to the control group, biofilms developed on starch or starch+sucrose had more proteinase activity (p<0.001), whereas biofilms developed on glucose or sucrose had more phospholipase activity (p<0.05). Exposure to starch+sucrose increased the production of extracellular and intracellular polysaccharides (p<0.05). Biofilms developed on starch or without carbohydrate supplementation presented cells with more hydrophobic behavior compared to the other groups. Confocal images showed hyphae forms on biofilms exposed to starch or starch+sucrose. Within the conditions studied, it can be concluded that dietary carbohydrates can modulate biofilm development on the denture surface by affecting virulence factors and structural features.
Santana, Ivone Lima; Goncalves, Leticia Machado; de Vasconcellos, Andrea Araujo; da Silva, Wander Jose; Cury, Jaime Aparecido; Cury, Altair Antoninha Del Bel
Sensitivity or pain of the mucoperiosteum covering the mandibular edentulous ridge is often thought to limit bite forces in complete-denture wearers. Therefore, bite forces with mandibular implant-retained overdentures may depend on the degree of implant support. This study analyzed the effects of different degrees of support for the mandibular denture on bite forces measured four years after denture treatment as
EA Fontijn-Tekampl; A. P. Slagter; M. A. van't Hof; M. E. Geertman; W. Kalk
The effects of attachment clips on force transmission in two implant-stabilised over-dentures with cantilever extensions were investigated, using a previously developed in-vitro model, which simulated functional mandibular deformation. Two retentive configurations were used: an avoid gold bar cranked anteriorly with 13 mm distal cantilevers and the same configuration without attachment clips on the distal cantilevers. The dentures were loaded at individual tooth positions with a strain gauge beam and the forces exerted on the implants were measured using strain gauges mounted on their trans-mucosal abutments. The difference between the two retentive configurations was significant (P < 0.05) as tested by ANOVA. It is concluded that the retentive configuration without clips on the distal cantilevers results in a significant decrease in compressive forces on the implants. PMID:12526275
el-Sheikh, Ali M; Hobkirk, John A
This study is concerned with the construction of a mathematical model of mandibular movement on the Hanau articulator and a complete denture occlusion simulation system (CDOSS) in the field of dental restoration. On the basis of the theory of spatial mechanisms, degrees of freedom in the kinematic chain of the Hanau articulator are analysed, and a hypothesis of constraints is presented to obtain constrained motion. Then, a series of mathematical expressions are derived to describe the three dimensional mandibular movement on the Hanau articulator. By adopting techniques and tools such as laser scanning, computer graphics, and computer databases, a 3D digitized model of complete denture is reconstructed, and a CDOSS is developed. With the aid of this software, the visualization and diagnosis of mandibular movement can be easily realized. One edentulous case discussed in this study shows that CDOSS provides a useful tool to deal with the functional aspects of occlusal morphology in a diagnostic and therapeutic sense. PMID:16772218
Xiaojun, C; Rubo, L; Eryi, L; Chengtao, W
A novel kind of denture base nanocomposite was prepared by polymethyl methyacrylate(PMMA) and cethyltrimethylammonium bromide\\u000a modified organic montmorillonite (OMMT). The dispersion of montmorillonite in the polymer matrix was characterized by x-ray\\u000a diffraction (XRD) and transimission electron microscope (TEM).The content of residual MMA in nanocomposites and the amount\\u000a of MMA released to water from nanocomposites were determined by gas chromatography (GC).
Hongbo Li; Chao Zhang; Zhi’an Li; Yining Wang; Qun Xiao
The aim of this study was to evaluate the reinforcing effects of three types of fibers at various concentrations and in different combinations on flexural properties of denture base resin. Glass (GL), polyaromatic polyamide (PA) and ultra-high molecular weight polyethylene (PE) fibers were added to heat-polymerized denture base resin with volume concentrations of 2.6%, 5.3%, and 7.9%, respectively. In addition, hybrid fiber-reinforced composite (FRC) combined with either two or three types of fibers were fabricated. The flexural strength, modulus and toughness of each group were measured with a universal testing machine at a crosshead speed of 5 mm/min. In the single fiber-reinforced composite groups, the 5.3% GL and 7.9% GL had the highest flexural strength and modulus; 5.3% PE was had the highest toughness. Hybrid FRC such as GL/PE, which showed the highest toughness and the flexural strength, was considered to be useful in preventing denture fractures clinically. PMID:23207213
Yu, Sang-Hui; Lee, Yoon; Oh, Seunghan; Cho, Hye-Won; Oda, Yutaka; Bae, Ji-Myung
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
The distribution of epithelial E-cadherin, basement membrane type VII collagen, and underlying connective tissues fibronectin were investigated immunohistochemically and compared in normal palatal mucosa and in denture-related stomatitis (DRS) derivatives using monoclonal antibodies.Biopsies of palatal mucosa were obtained from twelve patients enrolled in this study, 8 with type II DRS and 4 with healthy mucosa. Our findings bring to the fore, using the expression of three components (E-cadherin, collagen type VII, fibronectin), the continuities of the disorder among epithelial, basement membrane and connective tissue in the case of DRS. In type II denture-related stomatitis, we found an expression of E-cadherinin all the strata of epithelia, and the diffuse and strong expression of type VII collagen at the interface between connective tissue and epithelial cells with discontinuities in BM. The strong expression of fibronectin in underlying connective tissue with penetration in some areas of the palatal mucosa may be an early consequence of advanced DRS. Nevertheless; no single change is pathognomonic of this inflammatory process. In normal tissues (healthy clinical aspect), E-cadherin was found to be restricted to the upper strata of the epithelia, and type VII collagen revealed thin linear staining in the basement membrane and fibronectin in underlying connective tissue combined epithelia. In the case of denture-related stomatitis DRS, these three markers reflect the immunohistological modifications from the superficial layer of the epithelium to the lamina propria.
Bars, Pierre Le; Soueidan, Assem
The development of different types of materials with application in practice dentistry is an area of intense growth and research due to its importance in oral health. Among the diverse materials currently used in restoration or in dentures, the acrylic based resins have been widely employed. The release of toxic components and the changes on their physical and mechanical properties actually represent a goal of intensive research. In vivo analysis showed that the surface roughness of the acrylic resin represents a factor that could stimulate bacteria colonization and soft tissue inflammation. For this purpose, in this work, we have analyzed the cell response to acrylic based resins Ivoclar, Tokuso and Coldpack in basal conditions, unpolished, and after the polished procedure performed to reduce the surface roughness. Our in vitro results using human gingival fibroblasts (HGFs) showed a decrease of cell growth, evaluated by MTT assay starting at 24 h of incubation, in samples seeded on resins in basal conditions and after the polished procedure. This cell growth reduction was associated to evident morphological changes in unpolished materials. After 24 h of culture in presence of polished and unpolished resins a spontaneous release was present of pro-inflammatory cytokines such as interleukin-6 (IL-6) and -8 (IL-8), which was higher in unpolished resins, indicating that the polished procedure, minimizing the cytotoxicity process, could contribute to reduce the gingival inflammation processes. PMID:23058014
Trubiani, O; Toniato, E; Di Iorio, D; Diomede, F; Merciaro, I; D' Arcangelo, C; Caputi, S
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
The purpose of this in vitro study was to evaluate the color stability of two brands of porcelain teeth and three brands of acrylic denture teeth. Samples were immersed into three staining drinks as test groups and distilled water as a control. Color measurements of teeth were performed by using a spectrophotometer. Before immersion, the initial color value of each tooth was recorded. Color change values were determined after 1 day, 1 week, 2 weeks, and 4 weeks of immersion. Color differences were characterized using the CIE L*a*b* color space. The color stability of all teeth was significantly affected by the immersion period (p<0.0001). Instant coffee was found to be the most chromogenic agent among the solutions tested (p<0.0001). Among the materials tested, porcelain was found to be more resistant to discoloration. It was concluded that acrylic teeth showed a higher degree of color change and that the amount of color change for each group increased proportionally with time. PMID:18309623
Koksal, Temel; Dikbas, Idil
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
Machado, Ana L; Bochio, Bruna C; Wady, Amanda F; Jorge, Janaina H; Canevarolo, Sebastião V; Vergani, Carlos E
This study was to evaluate the colour change of soft denture liners after thermocycling and storage in coffee and coke. Four liners, two silicone-based (Sofreliner S and Reline GS) and two acrylic resin-based (Soft Confort and Dentuflex), were evaluated in this study. Ten samples were obtained for each group. After 2000 cycles of thermocycling with baths of 5°C and 55°C, five samples were stored in coffee and the remaining samples in coke. The colour alteration was evaluated in a reflection spectrophotometer before and after thermocycling, and after 1, 3, 24, 48 and 96h of storage in coffee and coke. Data were submitted to anova and Tukey's HSD test (?=0.05). Thermocycling and storage period represented a higher statistically significant influence for the resin liners than for the silicone materials. Coke did not influence the colour stability of the materials during storage. However, the coffee solution generated statistically significant colour alteration in the material Soft Confort. In the comparison between the coffee and coke solutions, there was no statistically significant difference for colour alteration only for the material Dentuflex. The silicone liners presented better colour stability following thermocycling and storage independent of the solution. The coffee solution was a statistically significant factor for colour alteration of the material Soft Confort. PMID:20082643
Goiato, Marcelo Coelho; Zuccolotti, Bruna Carolina Rossatti; Moreno, Amália; dos Santos, Daniela Micheline; Pesqueira, Aldiéris Alves; Dekon, Stefan Fiuza de Carvalho
This in vitro study evaluated the wear effects of five posterior denture tooth materials on human enamel. The tooth specimen was cusp shaped and enamel specimen was formed as a 10 C 10 C 5 mm plate. All material-enamel combinations were tested using a machine designed to produce sliding contact 20 C 104 times at 60 cycles min-1 and a 4-mm sliding distance per stroke in the bucco-lingual direction under a load of 1 kg. Wear analysis was measured as the total height loss of each combination. In addition, the surface roughness (Ra) of each worn specimen was also evaluated. The least total height loss occurred with poly (methyl methacrylate) (PMMA) enamel pair, and the greatest did with porcelain (Po)-enamel pair. The lowest compound Ra value was measured in high-strength resin (HR)-enamel pair, and the highest in Po-enamel pair. These findings suggest that the best combination is PMMA-enamel, and the poorest combination is Po-enamel. PMID:11380779
Abe, Y; Sato, Y; Taji, T; Akagawa, Y; Lambrechts, P; Vanherle, G
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).
Bochio, Bruna C; Wady, Amanda F; Jorge, Janaina H; Canevarolo, Sebastiao V; Vergani, Carlos E
In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties. Objective This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). Material and Methods Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37ºC for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37ºC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (?=0.05) and the failure modes were visually classified. Results No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. Conclusions Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.
ALCANTARA, Cristiane S.; de MACEDO, Allana F.C.; GURGEL, Bruno C.V.; JORGE, Janaina H.; NEPPELENBROEK, Karin H.; URBAN, Vanessa M.
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)
The purpose of this study was to determine how elderly Japanese people subjectively value treatment options for missing molars. Subjects were 528 independently community-dwelling elderly people. They were presented with photographs and descriptions of the process and expected outcomes of five possible treatment options: cantilever fixed dental prosthesis (FDP); resin or metal removable partial denture prosthesis (RPDP); implant-supported fixed prosthesis; and no replacement (shortened dental arch: SDA) for missing lower bilateral first and second molars. The participants filled in the questionnaire on subjective importance for treatment and indicated on a visual analogue scale how they valued the treatment (utility value: UV). Values were analysed by Mann-Whitney U-tests and multiple logistic regression analyses. Overall, the UVs for the FDP and the metal RPDP were the highest, and the UV for the SDA was the lowest. With respect to subjective importance, 'chewing ability' and 'no pain during function' were significantly selected more frequently. Multiple logistic regression analyses showed that the UV for the resin RPDP had significant positive associations with denture wearers and low treatment cost, whereas the implant had significant negative associations with denture wearers and older age. The SDA had significant positive associations with men and low treatment cost and a negative association with appearance. In conclusion, these elderly Japanese preferred cantilever FDPs and metal RPDPs to implants and 'no replacement.' It suggests that the SDA as an oral health goal can be questionable from the patients' point of view, even if it is biologically correct. PMID:20633073
Ikebe, K; Hazeyama, T; Kagawa, R; Matsuda, K; Maeda, Y
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).
This clinical report describes the 5-year follow-up treatment of an 11-year-old boy with ectodermal dysplasia. The dentition was initially restored with a combination of maxillary anterior-bonded composite restorations and a mandibular complete denture. This individualized approach allowed successful management of the patient. PMID:20202100
Khazaie, Reza; Berroeta, Eva M; Borrero, Camila; Torbati, Arman; Chee, Winston
...dentist. (b) The Food and Drug Administration...misbranded under the Federal Food, Drug, and Cosmetic...home-repaired dentures may cause faster bone loss, continuing...injury to the gums and faster bone loss, which is...502(a) of the Federal Food, Drug, and...
...dentist. (b) The Food and Drug Administration...misbranded under the Federal Food, Drug, and Cosmetic...home-repaired dentures may cause faster bone loss, continuing...injury to the gums and faster bone loss, which is...502(a) of the Federal Food, Drug, and...
...dentist. (b) The Food and Drug Administration...misbranded under the Federal Food, Drug, and Cosmetic...home-repaired dentures may cause faster bone loss, continuing...injury to the gums and faster bone loss, which is...502(a) of the Federal Food, Drug, and...
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
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.
Nidawani, Prakash; Galagali, Girish; Reddy, E Srinivas; Behera, Sidhartha S P
Nonlinear Partial Least Squares Edward Carl Malthouse We propose a new nonparametric regression method for high-dimensional data, nonlinear partial least squares (NLPLS). NLPLS is motivated by projection-based regression methods, e.g., partial least squares (PLS), projection pursuit (PPR), and feedforward neural networks. The model takes the form of a composition of two functions. The first function in the composition projects the
Edward Carl Malthouse
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
For a long time, classification of partial discharges was performed by eye, by studying discharge patterns at the ellipse of an oscilloscope screen. The introduction of digital processing techniques allowed automation of the recognition procedure. These procedures are reported and applied to a number of actual HV constructions which suffer from partial discharges. The results of these tests show that
F. H. Kreuger; E. Gulski; A. Krivda
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.Â Two file formats, gif and QuickTime files are used for the animations which can be downloaded.
Roberts, Lila F.; Hill, David R.
Soft denture liners act as a cushion for the denture bearing mucosa through even distribution of functional load, avoiding local stress concentrations and improving retention of dentures there by providing comfort to the patient. The objective of the present study was to compare and evaluate the tensile bond strengths of silicone-based soft lining materials (Ufi Gel P and GC Reline soft) with different surface pre treatments of heat cure PMMA denture base acrylic resin. Stainless steel dies measuring 40 mm in length; 10 mm in width and 10 mm in height (40 × 10 × 10) were machined to prepare standardized for the polymethyl methacrylate resin blocks. Stainless steel dies (spacer for resilient liner) measuring 3 mm thick; 10 mm long and 10 mm wide were prepared as spacers to ensure uniformity of the soft liner being tested. Two types of Addition silicone-based soft lining materials (room temperature polymerised soft lining materials (RTPSLM): Ufi Gel P and GC Reline soft) were selected. Ufi Gel P (VOCO, Germany), GC Reline soft (GC America) are resilient, chairside vinyl polysiloxane denture reliners of two different manufacturers. A total of 80 test samples were prepared of which 40 specimens were prepared for Group A (Ufi Gel P) and 40 specimens for Group B (GC Reline soft). In these groups, based on Pre-treatment of acrylic resin specimens each group was subdivided into four sub groups of 10 samples each. Sub-group I-without any surface treatment. Sub-group II-sand blasted Sub-group III-treated with Methyl Methacrylate monomer Sub-group IV-treated with chemical etchant Acetone. The results were statistically analysed by Kruscal Wallis test, Mann-Whitney U test, and Independent t test. The specimens treated with MMA monomer wetting showed superior and significant bond strength than those obtained by other surface treatments. The samples belonging to subgroups of GC Reline soft exhibit superior tensile bond strength than subgroups of Ufi Gel P. The modes of failure of all specimens were mostly adhesive in nature. Surface pre treatments by chemical means improved the bond strength between the silicone liners and denture base. PMID:24431747
Surapaneni, Hemchand; Ariga, Padma; Haribabu, R; Ravi Shankar, Y; Kumar, V H C; Attili, Sirisha
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.
\\u000a Partial rotator cuff ruptures are not rare and occur mainly in the supraspinatus tendon and may extend to that of infraspinatus,\\u000a but rarely to the tendon of subscapularis. Isolated lesions in the tendons of infraspinatus, teres minor or subscapularis\\u000a are rare. Partial ruptures usually occur before the sixth decade of life and can be a cause of unexplained pain in
Various triglycerides (coconut oil, palm kernel oil, tallow) were ethoxylated with a proprietary catalyst (calcium\\/aluminum\\u000a alkoxide complex partially neutralized in an alcohol ethoxylate base) to obtain triglyceride ethoxylates. Triglyceride ethoxylates\\u000a were then partially saponified with sodium hydroxide to form mixtures of mono-, di-, and triglyceride ethoxylates, fatty acid\\u000a soap, and glycerol ethoxylate. These mixtures were characterized in terms of physical
Michael F. Cox; Upali Weerassoriya
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: email@example.com [Department of Computational and Data Sciences, George Mason University, 4400 University Drive, Fairfax, VA 22030 (United States)
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
Objectives and methods: The curing of several commercial powder\\/liquid mixtures of acrylic denture base materials was carried out at different temperatures and curing times. The levels of residual mononer, tensile strength, percentage elongation before break and water absorption were measured.Results and Conclusion: It was found that the level of residual monomer determined by gas-liquid chromatography decreased with curing time and
A. Do?an; B. Bek; N. N. Çevik; A. Usanmaz
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
Conventional lasers consist of two components: a gain material that is pumped in order to provide amplification of light and a cavity to provide feedback. Random lasers replace the traditional laser cavity with a random, multiple-scattering medium. This can give rise to complex lasing behavior, such as unpredictable multidirectional and multifrequency output. Controlling these systems has proved difficult and, until now, has consisted of material and structural manipulations. In random lasers, the most common pumping mechanism is an optical field, which can be applied uniformly or partially across the scattering medium. Partial pumping, referring to the restricted spatial extent of the pump applied to the gain material, is therefore quite ubiquitous in such systems. In contrast to conventional lasers, however, the impact of partial pumping can be significant in random lasers as a subset of the scattering medium is probed. In this review, we discuss state-of-the-art investigations of partially pumped random lasers. Numerical and experimental investigations of how even a simple spot profile of the pump can dramatically alter random laser output are presented. First, the simple case of partial pumping in strongly scattering systems where laser modes are spatially confined is described. Then the most common but more difficult case of weakly scattering random lasers is considered. Here, modes are spatially extended, forcing greater mode interaction and making the random laser output more difficult to predict. Finally, we review recent works that show how the pumping degree of freedom allows a general increase in control over random lasers.
Andreasen, Jonathan; Bachelard, Nicolas; Bhaktha, Shivakiran B. N.; Cao, Hui; Sebbah, Patrick; Vanneste, Christian
To investigate the influence of dentures on electromagnetic energy absorption during the daily use of a mobile phone, a high-resolution head phantom based on the Visible Chinese Human dataset was reconstructed. Simulations on phantoms with various dentures were performed by using the finite-difference time-domain method with a 0.47 wavelength dipole antenna and a mobile phone model as radiation sources at 900 and 1800 MHz. The Specific energy Absorption Rate (SAR) values including 1 and 10 g average SAR values were assessed. When the metallic dental crowns with resonance lengths of approximately one-third to one-half wavelength in the tissue nearby are parallel to the radiation source, up to 121.6% relative enhancement for 1 g average SAR and 17.1% relative enhancement for 10 g average SAR are observed due to the resonance effect in energy absorption. When the radiation sources operate in the normal configuration, the 10 g average SAR values are still in compliance with the basic restrictions established by the Institute of Electrical and Electronic Engineers (IEEE) and the International Commission on Non-Ionizing Radiation Protection (ICNIRP), indicating that the safety limits will not be challenged by the usage of dentures. PMID:22388567
Yu, Dong; Zhang, Ruoyu; Liu, Qian
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
Erkan Erkmen; Gökçe Meriç; Ahmet Kurt; Yahya Tunç; At?l?m Eser
Conventional implant protocols required a load-free healing period of three to six months between placement and functional loading of the implants. Many efforts have been made to minimize the duration of treatment time. Several literatures have documented immediate function with provisional or definitive prosthesis within a week of the placement in response to these demands. In addition, immediate implant placement has advantages such as shortened treatment time and preservation of soft tissue architectures. This article presents immediate implant placement into fresh extraction sockets followed by functional immediate loading with provisional prosthesis on canine and premolars for a patient having canine protected occlusion.
Hong, Jun-Won; Ahn, Seung-Geun; Leem, Dae-Ho
By means of finite element analysis, the optimal thickness of fiber framework placed in a fiber-reinforced composite bridge replacing the mandibular first molar was obtained. Test results demonstrated that more than 30% maximum principal stress was reduced by reinforcing with fiber framework in a thickness of up to 0.6 mm for 1.5-mm occlusal clearance. Indeed, maximum principal stress generated in lower embrasure of connectors was reduced from 107 MPa to 70 MPa by maximizing reinforcement effect. PMID:17621946
Ootaki, Masayuki; Shin-Ya, Akikazu; Gomi, Harunori; Shin-Ya, Akiyoshi; Nakasone, Yuji
In this paper, partial spread OFDM system has been presented and its performance has been studied when different detection techniques are employed, such as minimum mean square error (MMSE), grouped Maximum Likelihood (ML) and approximated integer quadratic programming (IQP) techniques . The performance study also includes applying two different spreading matrices, Hadamard and Vandermonde. Extensive computer simulation have been implemented and important results show that partial spread OFDM system improves the BER performance and the frequency diversity of OFDM compared to both non spread and full spread systems. The results from this paper also show that partial spreading technique combined with suboptimal detector could be a better solution for applications that require low receiver complexity and high information detectability.
Elghariani, Ali; Zoltowski, Michael D.
A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured.
Dees, Dennis W. (Downers Grove, IL)
A method for detecting oxygen partial pressure and an oxygen partial pressure sensor are provided. The method for measuring oxygen partial pressure includes contacting oxygen to a solid oxide electrolyte and measuring the subsequent change in electrical conductivity of the solid oxide electrolyte. A solid oxide electrolyte is utilized that contacts both a porous electrode and a nonporous electrode. The electrical conductivity of the solid oxide electrolyte is affected when oxygen from an exhaust stream permeates through the porous electrode to establish an equilibrium of oxygen anions in the electrolyte, thereby displacing electrons throughout the electrolyte to form an electron gradient. By adapting the two electrodes to sense a voltage potential between them, the change in electrolyte conductivity due to oxygen presence can be measured. 1 fig.
Partial liver transplantation, including reducedsize liver transplantation, split liver transplantation, and living donor liver transplantation, has been developed with several innovative techniques because of donor shortage. Reduced-size liver transplantation is based on Couinaud's anatomical classification, benefiting children and small adult recipients but failing to relieve the overall donor shortage. Split liver transplantation provides chances to two or even more recipients when only one liver graft is available. The splitting technique must follow stricter anatomical and physiological criteria either ex situ or in situ to ensure long-term quality. The first and most important issue involving living donor liver transplantation is donor safety. Before surgery, a series of donor evaluations-including anatomical, liver volume, and liver function evaluations-is indispensable, followed by ethnic agreement. At different recipient conditions, auxiliary liver transplantation and auxiliary partial orthotopic liver transplantation, which employ piggyback techniques, are good alternatives. Partial liver transplantation enriches the practice and knowledge of the transplant society. PMID:21681668
Gong, Nianqiao; Chen, Xiaoping
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.
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.
Safe sets are a basic ingredient in the strategy of partial control of chaotic systems. Recently we have found an algorithm, the sculpting algorithm, which allows us to construct them, when they exist. Here we define another type of set, an asymptotic safe set, to which trajectories are attracted asymptotically when the partial control strategy is applied. We apply all these ideas to a specific example of a Duffing oscillator showing the geometry of these sets in phase space. The software for creating all the figures appearing in this paper is available as supplementary material.
Sabuco, Juan; Sanjuán, Miguel A. F.; Yorke, James A.
Safe sets are a basic ingredient in the strategy of partial control of chaotic systems. Recently we have found an algorithm, the sculpting algorithm, which allows us to construct them, when they exist. Here we define another type of set, an asymptotic safe set, to which trajectories are attracted asymptotically when the partial control strategy is applied. We apply all these ideas to a specific example of a Duffing oscillator showing the geometry of these sets in phase space. The software for creating all the figures appearing in this paper is available as supplementary material. PMID:23278093
Sabuco, Juan; Sanjuán, Miguel A F; Yorke, James A