Photoelastic Stress Analysis in Screwed and Cemented Implant-Supported Dentures With External Hexagon Implants

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Prevalence of removable partial dentures users treated at the Aracatuba Dental School - UNESP

Objectives: The aim of this study was to evaluate the frequency of removable partial dentures (RPD) at the Aracatuba Dental School.Methods: The study was conducted by analysing 412 clinical history of patients attended at the RPD clinics in the period from 2000 to 2007.Results: 412 charts were analysed: 148 (35.9%) men and 264 (64.1%) women. The mean age was 53.8 years (men) and 52.4 years (women). A total of 556 dentures were made; of these, 233 (41.90%) were maxillary and 323 (58.09%) were mandibular dentures. The most frequent Kennedy classification found was Class III (maxilla) and Class I (mandible). In the maxilla, 55% (126) of the major connectors were of the anterior-posterior palatal bar, while in the mandible, 64% (202) were the lingual bar. As regards the claps, 401 were circumferential and 318 were bar claps.Conclusion: The mean age of the patients was 52.9 years with higher prevalence of female patients; the most frequent Kennedy's classification was Class I in mandible and Class III in maxilla; the most common major connector was anterior-posterior palatal bar for maxilla and lingual bar for mandible; the circumferential clasps were the most common retainer used in both jaws.

Insertion and follow-up of complete dentures: a literature review

Insertion and follow-up of complete dentures: a literature reviewObjective: The aim of this study was to present the importance of clinical procedures related to insertion and follow-up of complete dentures in elderly patients.Materials and Methods: The success of rehabilitation with complete dentures results from the accuracy of clinical and laboratorial procedures that makes the denture insertion an important step of treatment.Conclusion: The follow-up and professional maintenance of function and hygiene facilitates long-term efficiency.

A comparison of patient satisfaction between treatment with conventional complete dentures and overdentures in the elderly: a literature review

Background:It has been stated that mandibular overdentures are more satisfactory than conventional dentures, but problems relating to the use of retrospective ratings, lack of control group and sequential provision of treatment may compromise the findings.Objective:To establish a comparison between treatment with conventional complete dentures and implant-retained overdentures in elderly patients by conducting a literature review.Materials and methods:A search of English language peer-review literature was completed using Medline up to 2008 focusing on evidence-based research. Randomised clinical trials (RCTs) and longitudinal prospective studies were favoured in the review, using a general hierarchical classification. Articles that did not focus exclusively on the comparison of patient satisfaction between complete dentures and overdentures were excluded from further evaluation. The last search was conducted in February 2008. Key terms included quality of life, patient satisfaction, edentulism, complete denture and overdenture.Results:Among the 90 articles found in the initial search, 27 met the inclusion criteria. This included 18 RCTs and eight prospective and one cohort study. Most of the articles stated superiority of the mandibular implant-retained overdenture therapy over the conventional complete denture regarding patient satisfaction and quality of life.Conclusion:Even with implant treatment presenting higher patient satisfaction and improvement of quality of life, it was not possible to establish a direct comparison between the studies due to differences in adopted methodologies.

Evaluation of the influence of location of osseointegrated implants associated with mandibular removable partial dentures

Purpose: The aim of this research was to assess, by means of, the bi-dimensional finite element method, the best implant location in the alveolar edge, through stress distribution and support structure displacement of a distal extension removable partial denture associated with an osseointegrated implant of 10.0 x .75 mm, acting as abutment for the denture base.Methods and Materials: Five models in sagittal cut were used to represent: model A-hemi arch containing natural tooth 33 and the distal alveolar edge; model B-similar to model A, but with a conventional removable partial denture to replace the absent teeth; model C (MC)-similar to the previous one, with an implant in the distal region of the edge under the denture base; model D-similar to MC, with the implant in the central region of the edge; model E-similar to MC, with an implant in the mesial region of the edge. With the aid of the finite element program ANSYS 8.0, the models were loaded with strictly vertical forces of 50 N on each cusp tip. Displacement and von Mises Maps were plotted for visualization of results.Results: The introduction of implant diminished the tendency of intrusion of the removable partial denture in all situations. The maximum stress was observed on implant in all situations. Approximating implant in direction of support teeth was benefit for stress distribution.Conclusion: Model D presented the lowest value for maximum tendency to displacement when compared with those found in the other models; model E demonstrated better relief with regard to demand from the abutment tooth; locating the implant near of the abutment tooth influenced positively the distribution of stresses on the analyzed structures.

Electromyographic activity of the mandible muscles at the beginning and end of masticatory cycles in patients with complete dentures

The aim of this study was to assess the electrical activity of the masseter and anterior temporal muscles in subjects with severe bone resorption at two different times: ( a) the initial period, with the complete dentures they had worn for over 10 years, and (b) the final period, 5 months after having new dentures put into place. Twelve asymptomatic subjects were asked to respond to the questionnaire, according to the research diagnostic criteria for temporomandibular disorders, before denture rehabilitation and 5 months after the new dentures were put in place. The electrical activity of the muscles was recorded during mastication in the initial and final period, using artificial food (Optocal). The operator monitored the 35 chewing cycles that were repeated to grind the artificial food. After wearing the new dentures for 5 months, the right anterior temporal muscle showed a statistical difference before and after denture rehabilitation at the beginning and end of mastication. Muscular capacity and ability reduced the electrical activity in the masseter muscles after rehabilitation. Copyright (c) 2008 S. Karger AG, Basel.

TMJ Vibrations in Asymptomatic Patients Using Old and New Complete Dentures

Purpose: The aim of this study was to assess the presence of temporomandibular joint (TMJ) noises in subjects with severe bone resorption, who have worn the same complete dentures for over 10 years, and 5 months after treatment with increments of acrylic resin on the occlusal surface after having new dentures in place.Methods: After applying the research diagnostic criteria (RDC)/temporomandibular disorder (TMD) questionnaire, 20 asymptomatic subjects were assessed before and 5 months after the new dentures were put in place. Joint vibrations were assessed by the Sono Pak program by selecting the vibrations that occurred during the opening and closing cycle.Results: The means of the results revealed a nonnormal distribution and were submitted to Kruskal-Wallis statistical analysis (p < 0.05). The vibration means were of low intensity (<= 9.96 Hz). After rehabilitation, there was a reduction in the vibrations (<= 5.2 Hz) statistically significant only at the end of mouth opening with the old dentures when compared with the other cycles.Conclusion: The intensity and number of occurrences of joint vibrations were reduced after 5 months of wearing new dentures.

Photoelastic analysis to compare implant-retained and conventional obturator dentures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effectiveness of microwave disinfection of complete dentures on the treatment of Candida-related denture stomatitis

The effectiveness of microwave disinfection of maxillary complete dentures on the treatment of Candida-related denture stomatitis was evaluated. Patients (n = 60) were randomly assigned to one of four treatment groups of 15 subjects each; Control group: patients performed the routine denture care; Mw group: patients had their upper denture microwaved (650 W per 6 min) three times per week for 30 days; group MwMz: patients received the treatment of Mw group in conjunction with topical application of miconazole three times per day for 30 days; group Mz: patients received the antifungal therapy of group MwMz. Cytological smears and mycological cultures were taken from the dentures and the palates of all patients before treatment at day 15 and 30 of treatment and at follow-up (days 60 and 90). The effectiveness of the treatments was evaluated by Kruskal-Wallis and Mann-Whitney tests. Microbial and clinical analysis of the control group demonstrated no significant decrease in the candidal infection over the clinical trial. Smears and cultures of palates and dentures of the groups Mw and MwMz exhibited absence of Candida at day 15 and 30 of treatment. on day 60 and 90, few mycelial forms were observed on 11 denture smears (36.6%) from groups Mw and MwMz, but not on the palatal smears. Miconazole (group Mz) neither caused significant reduction of palatal inflammation nor eradicated Candida from the dentures and palates. Microwaving dentures was effective for the treatment of denture stomatitis. The recurrence of Candida on microwaved dentures at follow-up was dramatically reduced.

Comparison of the occlusal vertical dimension after processing complete dentures made with lingualized balanced occlusion and conventional balanced occlusion

Statement of problem. An increase in occlusal vertical dimension (OVD) may occur after processing complete dentures. Although many factors that generate this change are known, no information is available in the dental literature regarding the effect that the occlusal scheme may have on the change in OVD.Purpose. This in vitro study compared the increase in OVD, after processing, between complete dentures with teeth arranged in lingualized balanced occlusion and conventional balanced occlusion.Material and methods. Thirty sets of complete dentures were evaluated as follows: 15 sets of complete dentures were arranged in conventional balanced occlusion (control) and 15 sets of complete dentures were arranged in lingualized balanced occlusion. All dentures were compression molded with a long polymerization cycle. The occlusal vertical dimension was measured with a micrometer (mm) before and after processing each set of dentures. Data were analyzed using an independent t test (alpha=.05).Results. The mean increase in the OVD, after processing, was 0.87 +/- 0.21 mm for the control group and 0.90 +/- 0.27 mm for the experimental group. There was no significant difference between the groups.Conclusion. After processing, dentures set in lingualized balanced occlusion showed an increase in OVD similar to those set in conventional balanced occlusion.

Photodynamic inactivation of microorganisms present on complete dentures. A clinical investigation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effectiveness of chlorhexidine on the disinfection of complete dentures colonised with fluconazole-resistant Candida albicans: in vitro study

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A cross-over randomised clinical trial of eccentric occlusion in complete dentures

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)