The use of a magnetic attachment in a removable partial denture of a patient with periodontal tissue loss

O uso dos magnetos em prótese parcial removível é uma alternativa viável para eliminar a estrutura metálica que pode interferir na estética sem perder retenção e estabilidade. Os magnetos podem ser recomendados para pacientes com perda de tecido periodontal, desde que eles diminuam a transmissão de forças ao dente remanescente. O objetivo deste relato de caso clínico foi apresentar uma alternativa de tratamento protético para dentes pilares comprometidos periodontalmente e descrever as vantagens e desvantagens do uso dos magnetos em prótese parcial removível sobre os pontos de vista funcionais, biológicos e estéticos.

Reabilitação Oclusal com Prótese Parcial Removível Provisória Tipo “Overlay” – Relato de Caso

An appropriate design of a prosthetic rehabilitation should not impute the restoration of occlusal vertical dimension (OVD) to new prostheses, at the risk of the patient does not adapt to a new condition, since a certain amount of time is often necessary for adaptation to a new OVD. This article performed prosthetic rehabilitation with an overlay provisional removable partial denture prior to definitive treatment because the patient showed a considerable decrease in the OVD. Three techniques for OVD determination were used. It is possible to conclude that the use of interim removable partial dentures is of great importance at the beginning of the rehabilitation treatment in order to adapt the patient to a new occlusal condition.

Reabilitação Oclusal com Prótese Parcial Removível Provisória Tipo “Overlay” – Relato de Caso

An appropriate design of a prosthetic rehabilitation should not impute the restoration of occlusal vertical dimension (OVD) to new prostheses, at the risk of the patient does not adapt to a new condition, since a certain amount of time is often necessary for adaptation to a new OVD. This article performed prosthetic rehabilitation with an overlay provisional removable partial denture prior to definitive treatment because the patient showed a considerable decrease in the OVD. Three techniques for OVD determination were used. It is possible to conclude that the use of interim removable partial dentures is of great importance at the beginning of the rehabilitation treatment in order to adapt the patient to a new occlusal condition.

Estudo Clínico Longitudinal Comparativo da Condição Periodontal de Pilares Diretos de Próteses Parciais Removíveis Dento- Suportada e Dento-Muco-Suportada

Objective: To perform a long-term clinical evaluation of the periodontium of removable parti al denture (RPD) wearers, comparing the direct pillar teeth of tooth-supported and toothtissue supported RPDs. Method: Fifty patients with mean age of 45 years were enrolled in the study. The individuals were examined by a single examiner at the moment of denture installation and after 3, 6, 9 and 12 months. In each exam, the following parameters were verified: gingival recession (GR), probing depth (PD), plaque index (PI), gingival index (GI) e amount kerati nized mucosa (KM). All patients received oral hygiene instructions and prophylaxis and, when necessary, scaling and root planing. An analysis from the confidence interval was done to evaluate the endpoints regarding the type of denture in the direct pillar group. Results: The tooth-tissue supported dentures showed significantly higher GR, GI and PI values, and significantly lower KM values. Over time, neither of the types of denture presented statistically significant difference from the initial to the final examination for the parameters GR, PD, KM and GI, while the PI was significant only for the tooth-supported dentures. Conclusion: Pillar teeth adjacent to free ends presented a less favorable periodontal conditi on than the pillar teeth adjacent to intercalated spaces. However, the use of RPD did not aggravate the initial condition, after a follow-up period of 12 months. The findings of the study indicate that, within 1 year, there were no significant differences between the direct pillars of the toothsupported and tooth-ti ssue supported dentures, and suggest the need of professional follow up for a longer period.

Estudo Clínico Longitudinal Comparativo da Condição Periodontal de Pilares Diretos de Próteses Parciais Removíveis Dento- Suportada e Dento-Muco-Suportada

Objective: To perform a long-term clinical evaluation of the periodontium of removable parti al denture (RPD) wearers, comparing the direct pillar teeth of tooth-supported and toothtissue supported RPDs. Method: Fifty patients with mean age of 45 years were enrolled in the study. The individuals were examined by a single examiner at the moment of denture installation and after 3, 6, 9 and 12 months. In each exam, the following parameters were verified: gingival recession (GR), probing depth (PD), plaque index (PI), gingival index (GI) e amount kerati nized mucosa (KM). All patients received oral hygiene instructions and prophylaxis and, when necessary, scaling and root planing. An analysis from the confidence interval was done to evaluate the endpoints regarding the type of denture in the direct pillar group. Results: The tooth-tissue supported dentures showed significantly higher GR, GI and PI values, and significantly lower KM values. Over time, neither of the types of denture presented statistically significant difference from the initial to the final examination for the parameters GR, PD, KM and GI, while the PI was significant only for the tooth-supported dentures. Conclusion: Pillar teeth adjacent to free ends presented a less favorable periodontal conditi on than the pillar teeth adjacent to intercalated spaces. However, the use of RPD did not aggravate the initial condition, after a follow-up period of 12 months. The findings of the study indicate that, within 1 year, there were no significant differences between the direct pillars of the toothsupported and tooth-ti ssue supported dentures, and suggest the need of professional follow up for a longer period.

Análise mecânica e microestrutural das ligas de cobalto-cromo de uso odontológico após sucessivas refundições

The cobalt-chromium alloy is extensively used in the Odontology for the confection of metallic scaffolding in partial removable denture. During the last few years, it has been reported an increasing number of premature imperfections, with a few months of prosthesis use. The manufacture of these components is made in prosthetic laboratories and normally involves recasting, using parts of casting alloy and parts of virgin alloy. Therefore, the objective of the present study was to analyze the mechanical properties of a commercial cobalt-chromium alloy of odontological use after successive recasting, searching information to guide the dental prosthesis laboratories in the correct manipulation of the cobalt-chromium alloy in the process of casting and the possible limits of recasting in the mechanical properties of this material. Seven sample groups were confectioned, each one containing five test bodies, divided in the following way: G1: casting only with virgin alloy; G2: casting with 50% of the alloy of the G1 + 50% of virgin alloy; G3: casting with 50% of the alloy of the G2 + 50% of virgin alloy; G4: casting with 50% of the alloy of the G3 + 50% of virgin alloy; G5: 50% of alloy of the G4 + 50% of virgin alloy; G6: 50% of alloy of the G5 + 50% of virgin alloy and finally the G7, only with recasting alloy. The modifications in the mechanical behavior of the alloy were evaluated. Moreover, it was carried the micro structural characterization of the material by optic and electronic scanning microscopy, and X ray diffraction.and fluorescence looking into the correlatation of the mechanical alterations with structural modifications of the material caused by successive recasting process. Generally the results showed alterations in the fracture energy of the alloy after successive recasting, resulting mainly of the increasing presence of pores and large voids, characteristic of the casting material. Thus, the interpretation of the results showed that the material did not reveal significant differences with respect to the tensile strength or elastic limit, as a function of successive recasting. The elastic modulus increased from the third recasting cycle on, indicating that the material can be recast only twice. The fracture energy of the material decreased, as the number of recasting cycles increased. With respect to the microhardness, the statistical analyses showedno significant differences. Electronic scanning microscopy revealed the presence of imperfections and defects, resulting of the recasting process. X ray diffraction and fluorescence did not show alterations in the composition of the alloy or the formation of crystalline phases between the analyzed groups. The optical micrographs showed an increasing number of voids and porosity as the material was recast. Therefore, the general conclusion of this study is that the successive recasting of of Co-Cr alloys affects the mechanical properties of the material, consequently leading to the failure of the prosthetic work. Based on the results, the best recommendadition is that the use of the material should be limited to two recasting cycles

Análise mecânica e microestrutural das ligas de cobalto-cromo de uso odontológico após sucessivas refundições

The cobalt-chromium alloy is extensively used in the Odontology for the confection of metallic scaffolding in partial removable denture. During the last few years, it has been reported an increasing number of premature imperfections, with a few months of prosthesis use. The manufacture of these components is made in prosthetic laboratories and normally involves recasting, using parts of casting alloy and parts of virgin alloy. Therefore, the objective of the present study was to analyze the mechanical properties of a commercial cobalt-chromium alloy of odontological use after successive recasting, searching information to guide the dental prosthesis laboratories in the correct manipulation of the cobalt-chromium alloy in the process of casting and the possible limits of recasting in the mechanical properties of this material. Seven sample groups were confectioned, each one containing five test bodies, divided in the following way: G1: casting only with virgin alloy; G2: casting with 50% of the alloy of the G1 + 50% of virgin alloy; G3: casting with 50% of the alloy of the G2 + 50% of virgin alloy; G4: casting with 50% of the alloy of the G3 + 50% of virgin alloy; G5: 50% of alloy of the G4 + 50% of virgin alloy; G6: 50% of alloy of the G5 + 50% of virgin alloy and finally the G7, only with recasting alloy. The modifications in the mechanical behavior of the alloy were evaluated. Moreover, it was carried the micro structural characterization of the material by optic and electronic scanning microscopy, and X ray diffraction.and fluorescence looking into the correlatation of the mechanical alterations with structural modifications of the material caused by successive recasting process. Generally the results showed alterations in the fracture energy of the alloy after successive recasting, resulting mainly of the increasing presence of pores and large voids, characteristic of the casting material. Thus, the interpretation of the results showed that the material did not reveal significant differences with respect to the tensile strength or elastic limit, as a function of successive recasting. The elastic modulus increased from the third recasting cycle on, indicating that the material can be recast only twice. The fracture energy of the material decreased, as the number of recasting cycles increased. With respect to the microhardness, the statistical analyses showedno significant differences. Electronic scanning microscopy revealed the presence of imperfections and defects, resulting of the recasting process. X ray diffraction and fluorescence did not show alterations in the composition of the alloy or the formation of crystalline phases between the analyzed groups. The optical micrographs showed an increasing number of voids and porosity as the material was recast. Therefore, the general conclusion of this study is that the successive recasting of of Co-Cr alloys affects the mechanical properties of the material, consequently leading to the failure of the prosthetic work. Based on the results, the best recommendadition is that the use of the material should be limited to two recasting cycles

Longitudinal Clinical Evaluation of Undercut Areas and Rest Seats of Abutment Teeth in Removable Partial Denture Treatment

PURPOSE: Adequate preparation of abutment teeth for removable partial denture (RPD) rest seats allows appropriate masticatory force transmission, retention, and stability of supporting structures. It follows that careful preparation will be important for the longevity of the rehabilitation. The present study aimed to clinically evaluate rest seats and undercut areas of abutment teeth in RPD wearers after 2 years of use. MATERIALS AND METHODS: A total of 193 occlusal, incisal, and cingulum rest seats were evaluated in terms of shape, rest adaptation, wear, caries, fractures, and surface type (enamel, composite resin, or amalgam). Two hundred and fourteen undercut areas were evaluated in terms of surface type (enamel or restoration) and integrity. This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, resolution 196/1996, protocol number 11/05. RESULTS: Intact preparations accounted for 92.2% of the total. Application of the Pearson test (p= 0.289) found no statistically significant differences among the materials on which the rest seats were prepared. For the undercut areas, 20.7% of those obtained on restorative material were nonintact. In addition, Fisher's exact test showed a statistically significant difference (p= 0.001) in surface type; enamel surfaces were shown to be 14 times more stable than restored surfaces. CONCLUSIONS: The results of this study suggest that rest seats are stable, regardless of the material on which they are prepared. Retentive areas were shown to be more stable when they were located in enamel.

Longitudinal Clinical Evaluation of Undercut Areas and Rest Seats of Abutment Teeth in Removable Partial Denture Treatment

PURPOSE: Adequate preparation of abutment teeth for removable partial denture (RPD) rest seats allows appropriate masticatory force transmission, retention, and stability of supporting structures. It follows that careful preparation will be important for the longevity of the rehabilitation. The present study aimed to clinically evaluate rest seats and undercut areas of abutment teeth in RPD wearers after 2 years of use. MATERIALS AND METHODS: A total of 193 occlusal, incisal, and cingulum rest seats were evaluated in terms of shape, rest adaptation, wear, caries, fractures, and surface type (enamel, composite resin, or amalgam). Two hundred and fourteen undercut areas were evaluated in terms of surface type (enamel or restoration) and integrity. This study was approved by the Research Ethics Committee of the Federal University of Rio Grande do Norte, resolution 196/1996, protocol number 11/05. RESULTS: Intact preparations accounted for 92.2% of the total. Application of the Pearson test (p= 0.289) found no statistically significant differences among the materials on which the rest seats were prepared. For the undercut areas, 20.7% of those obtained on restorative material were nonintact. In addition, Fisher's exact test showed a statistically significant difference (p= 0.001) in surface type; enamel surfaces were shown to be 14 times more stable than restored surfaces. CONCLUSIONS: The results of this study suggest that rest seats are stable, regardless of the material on which they are prepared. Retentive areas were shown to be more stable when they were located in enamel.

Impact on quality of life of removable partial denture wearers after 2 years of use

The use of clinical indicators of satisfaction (OHIP) can be applied to evaluate the impact of denture use on patient quality of life, since dental problems and disorders interfere in the normal life of individuals. Aim: This study aimed at evaluating the satisfaction level of patients rehabilitated with removable partial dentures (RPD) after 2 years of use. Methods: An observational study was carried out on 28 patients with a mean age of 45 years, treated with RPD at the Department of Dentistry of the Federal University of Rio Grande do Norte in 2005. Patients signed informed consent and answered the Oral Health Impact Profile (OHIP) questionnaire on three occasions: prior to rehabilitation and at 3 months and 2 years of denture use. Repeated-measures ANOVA was applied for data analysis. Results: A difference was found between data obtained at the moment of fitting and three months after denture use (p<0.001). However, no variation was observed when comparing data from 3 months and 2 years of use (p>0.05). The variables of gender and age did not interfere in the result (p>0.05). Conclusions: The degree of patient satisfaction after RPD installation was significant at the moment of fitting and 3 months after denture use, but no significant difference was found between 3 months and 2 years of denture use.

Impact on quality of life of removable partial denture wearers after 2 years of use

The use of clinical indicators of satisfaction (OHIP) can be applied to evaluate the impact of denture use on patient quality of life, since dental problems and disorders interfere in the normal life of individuals. Aim: This study aimed at evaluating the satisfaction level of patients rehabilitated with removable partial dentures (RPD) after 2 years of use. Methods: An observational study was carried out on 28 patients with a mean age of 45 years, treated with RPD at the Department of Dentistry of the Federal University of Rio Grande do Norte in 2005. Patients signed informed consent and answered the Oral Health Impact Profile (OHIP) questionnaire on three occasions: prior to rehabilitation and at 3 months and 2 years of denture use. Repeated-measures ANOVA was applied for data analysis. Results: A difference was found between data obtained at the moment of fitting and three months after denture use (p<0.001). However, no variation was observed when comparing data from 3 months and 2 years of use (p>0.05). The variables of gender and age did not interfere in the result (p>0.05). Conclusions: The degree of patient satisfaction after RPD installation was significant at the moment of fitting and 3 months after denture use, but no significant difference was found between 3 months and 2 years of denture use.

Dual path: a concept to improve the esthetic replacemente of missing anterior teeth with removable partial denture

The dual path of insertion concept for removable partial denture (RPD) design may be used in esthetically demanding situations. When compared to conventional RPDs, the main advantage of this design is the minimal use of clasps. This clinical report describes the treatment of a patient with an anterior maxillary edentulous area using a dual path RPD. The diagnostic cast was surveyed to ensure the adequacy of the undercuts on the mesial surfaces of the anterior abutments, where rigid minor connectors were placed. Inverted V-shaped canine cingulum rest seats were prepared to provide resistance to tooth movement during function. The dual path RPD concept allows excellent esthetic results, minimizes tooth preparation, and reduces the tendency toward plaque accumulation in a Kennedy class IV partially edentulous arch.

Ethics in the provision of removable partial dentures

Aim: To investigate the construction of cobalt-chromium removable partial dentures by commercial private dental laboratories. Methods: Ninety master casts for fabrication of cobalt-chromium removable partial dentures were obtained from three commercial laboratories randomly selected. Casts were assessed for dental arch treated, Kennedy classification, cast surveying, denture design information provided by the dentist, and mouth preparation (rest seat, guiding plane and retentive area). Dental technicians answered a questionnaire regarding qualification of assisted dentists, monthly number of framework castings, and use of dental surveyor. Mouth preparation was compared among laboratories using Kruskal-Wallis test (α=0.05). Results: The percentage of Kennedy class I was 16%, class II 19%, class III 56%, and class IV 9%. The majority of master cats (51%) examined was sent to dental laboratories without any design information and did not comply with ethical guidelines in the provision of RPD. Approximately half of the casts were considered “inappropriate” for guiding planes and retentive areas. One of the laboratories presented all casts “inappropriate” for rest seat distribution (p<0.001). Conclusions: Mouth preparation frequently failed for guiding planes, retentive areas and distribution of rest seats. It is necessary to provide students with adequate clinical experience at the dental school environment, which will actually be carried into the practice of dentistry.

Ethics in the provision of removable partial dentures

Aim: To investigate the construction of cobalt-chromium removable partial dentures by commercial private dental laboratories. Methods: Ninety master casts for fabrication of cobalt-chromium removable partial dentures were obtained from three commercial laboratories randomly selected. Casts were assessed for dental arch treated, Kennedy classification, cast surveying, denture design information provided by the dentist, and mouth preparation (rest seat, guiding plane and retentive area). Dental technicians answered a questionnaire regarding qualification of assisted dentists, monthly number of framework castings, and use of dental surveyor. Mouth preparation was compared among laboratories using Kruskal-Wallis test (α=0.05). Results: The percentage of Kennedy class I was 16%, class II 19%, class III 56%, and class IV 9%. The majority of master cats (51%) examined was sent to dental laboratories without any design information and did not comply with ethical guidelines in the provision of RPD. Approximately half of the casts were considered “inappropriate” for guiding planes and retentive areas. One of the laboratories presented all casts “inappropriate” for rest seat distribution (p<0.001). Conclusions: Mouth preparation frequently failed for guiding planes, retentive areas and distribution of rest seats. It is necessary to provide students with adequate clinical experience at the dental school environment, which will actually be carried into the practice of dentistry.

Avaliação da desadaptação das selas de próteses parciais removíveis após 1 a 5 anos de uso

The non-adaptation of the removable partial prosthesis (RPP) base to fibromucosal tissue is caused by resorption of residual ridges (RRR). The onset of bone resorption, which occurs after tooth extraction and continues throughout life, is accelerated by local or systemic factors. Aim: Assess the degree of non-adaptation of removable partial prosthesis saddles and the factors that influence it. Methodology: A sectional study was conducted with 81 patients using RPP who had their prostheses installed between 2003 and 2007 (1 to 5 years of use) at the Faculty of Dentistry of the Universidade Federal do Rio Grande do Norte (UFRN). After anamnese and clinical examination, a cast was made with polyether-based material, using the base of the prosthesis to make the impression. The base of the saddle was loaded with the casting material and positioned in the mouth, applying pressure on the supports. After polymerization, the material was removed from the saddle and measurements were taken at 3 different points using a pachymeter. Results: The non-adaptation of the saddle increased significantly with years of use (p = 0.005). The tooth-tissue supported prostheses obtained higher mean non-adaptation values than those of tooth supported prostheses (p < 0.001). Flaccid mucosa showed the worst non-adaptation results, which were statistically different from resilient mucosa (p < 0.001). The greater the extension of the saddle, the greater the non-adaptation (p < 0.001). The natural tooth antagonistic arch yielded better results than did RPP and total prosthesis (p < 0.001). Saddle non-adaptation at the free end was less near the pillar tooth and greater in the more posterior region (p < 0.001). When adaptation of the supports to the niches was poor, greater saddle non-adaptation occurred than when it was good or fair (p < 0.001). Saddles located in the posterior region of the arch had greater non-adaptation than those in the anterior region (p = 0.023). Conclusion: The mean non-adaptation of the saddle to the residual ridges was 0.27 mm. It can be concluded that, even with the use of RPP, bone height reduction was slight within the 1-5-year period of use. The following are factors that influence adaptation of the RPP saddle base: years of use, age, force transmission path to the alveolar bone, location of the toothless area, antagonistic arch, type of mucosa, adaptation of supports to the niche and extension of the saddle