Precisão das técnicas de moldagem e vazamento para próteses implantossuportadas

Dentre as inúmeras fases clínicas e laboratoriais de um tratamento protético, as técnicas de moldagem e vazamento para próteses implantossuportadas são ainda responsáveis por grande preocupação e controvérsia entre os pesquisadores. Este estudo in vitro teve como objetivo avaliar a precisão de uma técnica de registro (Index) e de três técnicas de moldagem (transferentes Cônicos, Quadrados e Quadrados unidos) associadas a três técnicas de vazamento (Convencional, com tubos de Látex e com análogos unidos com Duralay) para próteses implantossuportadas. Todos os componentes protéticos utilizados foram da empresa Conexão (Conexão Sistemas de Prótese). Foi construído um modelo mestre de latão simulando um arco inferior desdentado onde foram fixados provisoriamente quatro análogos de pilares Micro-Unit perpendicularmente à superfície e paralelos entre si, sendo denominados análogos A, B, C e D. Uma estrutura metálica foi confeccionada e parafusada a quatro novos análogos. Este conjunto foi cimentado passivamente no modelo mestre com resina epóxica. Foram confeccionadas (com 2 mm de alívio) uma moldeira individual de alumínio para a técnica com os transferentes quadrados unidos e outra para as técnicas com os transferentes cônicos e quadrados. O material de moldagem utilizado foi um poliéter (Impregum Soft Média Viscosidade - 3M ESPE) e o gesso empregado foi um gesso tipo IV (Vel-Mix, Kerr), espatulado à vácuo. Foi obtido um total de cinquenta modelos, sendo cinco por técnica. A estrutura metálica foi parafusada com um torque de 10 Ncm em todos os modelos no análogo A, enquanto as medições das fendas formadas foram feitas nos análogos C e D. Este processo foi repetido no análogo D, anotando-se as medidas dos análogos A e B. Estas medições foram feitas por um programa (Leica QWin) que recebia as imagens de uma câmara de vídeo...Among the countless clinical and laboratories procedures of a prosthetic treatment, the implant impression and pouring techniques for implant-supported restorations are still responsible for great concern and controversy among the researches. This study in vitro investigated the accuracy of a stone Index and of three impression techniques (tapered impression copings, squared impression copings and squared impression copings splinted with Duralay resin) associated to three pouring techniques (Conventional, with tubes of Latex and joining the analogs with Duralay resin) for an osseointegrated implant-supported prostheses. Conexão (Conexão Systems of Prosthesis) prosthetic components were used. A mandibular brass cast was constructed with four stainless steel implant abutments analogs 90° to the surface and parallel among themselves, being denominated analog A, B, C and D. A master framework was made and screwed to four new analogs, which were cemented passively into the model master with epoxy resin. This formed a metal implant cast with a passive implant framework fitted to it. An aluminum custom tray was fabricated for the technique copings splinted with Duralay and other for the techniques tapered and squared copings. Polyether impression material (Impregum Soft medium consistency - 3M ESPE) was used for all impressions. A total of fifty stone casts were formed by carefully vibrating improved dental stone (Vel-Mix, Kerr), mixed under vacuum, being five for technique. The standard framework was seated on each cast and guide pin was tightened in the analog A to 10 Ncm using a torque driver, while the measurements of abutment / framework interface gaps were made in analogs C and D. This process was repeated in analog D, being written down the measures of the analogs ones A and B. These measurements were analyzed using software (Leica QWin) that received the images of a video ...(Complete abstract, click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Precisão das técnicas de moldagem para próteses implantossuportadas

Desde que não há consenso em relação a técnica de moldagem mais precisa, foi objetivo deste estudo in vitro avaliar a precisão de 1 técnica de registro (Index de resina composta) e de 5 técnicas de moldagem para próteses implantossuportadas (transferentes quadrados, quadrados jateados, quadrados com extensão lateral, quadrados unidos com Duralay e quadrados unidos com barra de metal) empregando-se 3 materiais de moldagem: silicone de polimerização por adição consistência densa/fluida com moldeira de estoque de inox, poliéter média viscosidade e silicone de polimerização por adição consistência regular com moldeira individual. Foram construídos 1 modelo mestre com 4 análogos de pilares Micro-Unit e 1 estrutura metálica. Obteve-se do modelo mestre um total de 45 modelos, sendo 5 por técnica. A estrutura metálica foi parafusada utilizando-se a técnica de mensuração de fendas por um parafuso. Estas medições foram feitas com o auxílio do programa Leica QWin que recebeu as imagens de uma câmara de vídeo acoplada a uma lupa com um aumento de 100 x. Os resultados obtidos foram analisados estatisticamente utilizando o teste de Kruskal-Wallis seguido pelo método de Dunn, !=0,05. Dentro das condições experimentais deste estudo, podese concluir que não houve diferença estatística entre: modelo mestre (31,63 !m), quadrado Impregum (38,03 μm), quadrado jateado Impregum (46,80 μm), Index (45,25 μm) e quadrado com extensão lateral Express consistência densa/fluida (51,20 μm), sendo esta a eleita. Devido aos piores resultados obtidos com as técnicas quadrado Express regular (151,21 μm) e quadrado jateado Express regular (136,59 μm), o material de moldagem Express consistência regular não deve ser empregado, sendo escolhido então para ser utilizado com moldeiras individuais o Impregum viscosidade média. Caso o cirurgião-dentista pretenda realizar...Since there is still no consensus regarding the most accurate impression techniques, it was the purpose of this study compared the dimensional accuracy of stone index and of 5 impression techniques for implant-supported prostheses (squared impression copings, modified squared, !squared sandblasted and coated with impression adhesive, modified squared, Duralay splinted and metal splinted) using 3 impression materials: vinyl polysiloxane putty/light body with a metal stock tray and polyether medium consistency and vinyl polysiloxane regular body were used with a custom aluminum tray. A master cast with 4 parallel implant abutment analogs and a framework were fabricated. Nine groups (n=5) were tested. The gap measurement method employed was just one titanium screw tightened to the framework. Group’s measurements were analyzed using LeicaQWin software that received the images of a video camera coupled to a stereomicroscope at x100 magnification. The results were statistically analyzed with Kruskal-Wallis One Way ANOVA on Ranks test followed by Dunn's Method, !=.05. Under the conditions of this study the following conclusions could be drawn: no significant difference was detected among Master Cast (31.63 !m), Squared Impregum (38.03 !m), Sandblasted-Adhesive Squared Impregum (46.80 !m), Index (45.25 μm) and Modified Squared techniques (51.20 μm) (P=.05), being the elected. Due to the worst results with the techniques Squared Express Regular (151.21 μm) and Sandblasted-Adhesive Squared Express Regular (136.59 μm), the Express regular body impression material should not be used, and then chosen to be used Impregum Soft medium consistency with custom tray. If the dentist wishes to perform the technique with splinted copings (Metal Splinted = 68.55 !m and Duralay Splinted = 165.03 !m), the splint should be made with bars of metal. The impression technique using sandblasted-adhesive squared... (Complete abstract click electronic access below)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

Accuracy of Impression Techniques for an Implant-Supported Prosthesis

Purpose: This in vitro study compared the dimensional accuracy of a stone index and of two impression techniques (squared impression copings and modified squared impression copings) for implant-supported prostheses. Materials and Methods: A master cast with four parallel implant-abutment analogs and a passive framework were fabricated. Vinyl polysiloxane impression material was used for all impressions with a metal stock tray. Three groups of impressions were tested (n = 5): index (1), squared (S), and modified squared (MS). The measurement method employed was just one titanium screw tightened to the framework. The measurements (60 gap values) were analyzed using software that received the images from a video camera coupled to a stereomicroscope at x 100 magnification. The results were evaluated statistically (analysis of variance, Holm-Sidak method, alpha = .05). Results: The mean abutment/framework interface gaps were: master cast = 31.63 mu m; group I = 45.25 mu m; group S = 96.14 mu m; group MS = 51.20 mu m. No significant difference was detected among the index and modified squared techniques (P = .05). Conclusion: Under the limitations of this study, the techniques modified squared and index generated more accurate casts than the squared technique. INT J ORAL MAXILLOFAC IMPLANTS 2010;25:715-72

Accuracy of impression and pouring techniques for an implant-supported prosthesis

Purpose: The purpose of this in vitro study was to compare the dimensional accuracy of a stone index and of 3 impression techniques (tapered impression copings, squared impression copings, and squared impression copings splinted with acrylic resin) associated with 3 pouring techniques (conventional, pouring using latex tubes fitted onto analogs, and pouring after joining the analogs with acrylic resin) for implant-supported prostheses. Materials and Methods: A mandibular brass cast with 4 stainless steel implant-abutment analogs, a framework, and 2 aluminum custom trays were fabricated. Polyether impression material was used for all impressions. Ten groups were formed (a control group and 9 test groups formed by combining each pouring technique and impression technique). Five casts were made per group for a total of 50 casts and 200 gap values (1 gap value for each implant-abutment analog). Results: The mean gap value with the index technique was 27.07 mu m. With the conventional pouring technique, the mean gap values were 116.97 mu m for the tapered group, 5784 mu m for the squared group, and 73.17 mu m for the squared splinted group. With pouring using latex tubes, the mean gap values were 65.69 mu m for the tapered group, 38.03 mu m for the squared group, and 82.47 mu m for the squared splinted group. With pouring after joining the analogs with acrylic resin, the mean gap values were 141.12 jum for the tapered group, 74.19 mu m for the squared group, and 104.67 mu m for the squared splinted group. No significant difference was detected among Index, squarellatex techniques, and master cast (P > .05). Conclusions: The most accurate impression technique utilized squared copings. The most accurate pouring technique for making the impression with tapered or squared copings utilized latex tubes. The pouring did not influence the accuracy of the stone casts when using splinted squared impression copings. Either the index technique or the use of squared coping combined with the latex-tube pouring technique are preferred methods for making implant-supported fixed restorations with dimensional accuracy

The Effect of Splint Material Rigidity in Implant Impression Techniques

Purpose This in vitro study compared the dimensional accuracy of two impression techniques Duralay splinted impression copings (D) and metal splinted impression copings (M) for implant supported pros theses Materials and Methods A master cast with four parallel implant abutment analogs and a passive framework were fabricated Vinyl polysiloxane impression material was used for all impressions with a metal stock tray Two groups (D and M) were tested (n = 5) The measurement method employed was just one titanium screw tightened to the framework Each group s measurements were analyzed using software that received the images of a video camera coupled to a stereomicroscope at X100 magnification The results were analyzed statistically (t test) Results The mean values of abutment/framework interface gaps were master cast = 32 mu m (SD 2), group D = 165 mu m (SD 60), and group M = 69 mu m (SD 36) There was a statistically significant difference between the D and M groups (P <= 001) Conclusion Under the limitations of this study, it could be suggested that a more accurate working cast can be fabricated using metal splinted impression copings INT J ORAL MAXILLOFAC IMPLANTS 2010 25 1153-115

Comparison of impression techniques and materials for implant-supported prosthesis

Purpose: To investigate, in vitro, the dimensional accuracy of two impression techniques (squared impression copings and squared impression copings sandblasted and coated with impression adhesive) made of vinyl polysiloxane and polyether impression materials. Materials and Methods: A master cast (control group) with four parallel implant abutment analogs, a passive framework, and a custom aluminum tray was fabricated. Four groups (n = 5 each group) were tested: squared Impregum (SI), squared Express (SE), sandblasted adhesive squared Impregum (ASI), and sandblasted adhesive squared Express (ASE). The measurement method employed was just one titanium screw tightened to the framework. A stereomicroscope was used to evaluate the fit of the framework by measuring the size of the gap between the abutment and the framework. The results were analyzed statistically. Results: The mean values for the abutment/framework interface gaps were: master cast, 31.63 mu m (SD 2.16); SI, 38.03 mu m (SD 9.29); ASI, 46.80 mu m (SD 8.47); SE, 151.21 mu m (SD 22.79); and ASE, 136.59 mu m (SD 29.80). No significant difference was detected between the SI or ASI techniques and the master cast. No significant difference was detected between the SE and ASE techniques. Conclusion: Within the limitations of this study, it can be concluded that Impregum Soft medium consistency was the best impression material and the impression technique did not influence the accuracy of the stone casts. INT J ORAL MAXILLOFAC IMPLANTS 2010;25:771-77

Eight-Year Follow-Up of a Fixed-Detachable Maxillary Prosthesis Utilizing an Attachment System: Clinical Protocol for Individuals With Skeletal Class III Malocclusions

The aim of this article is to describe a successful clinical protocol for prosthodontic rehabilitation of a patient with a skeletal Class III malocclusion using a fixed-detachable maxillary prosthesis supported by 6 implants and the MK1 attachment system. The patient was followed up for 8 years. A 46-year-old edentulous woman with a skeletal Class III malocclusion expressed dissatisfaction with her old existing maxillary denture from an esthetic point of view and frustration regarding its function. A fixed-detachable maxillary prosthesis using the MK1 attachment system was made. The patient was followed up clinically and radiographically for 8 years. No bone loss, fracture of prosthetic components, or fracture of the prosthesis was detected in that period. A fixed detachable maxillary prosthesis using the MK1 attachment system is a treatment option for patients with Class III malocclusions who opt not to undergo orthognathic surgery

Comparison of the accuracy for three dental impression techniques and index: An in vitro study

Objectives: This in vitro study compared the dimensional accuracy of stone index (I) and three impression techniques: tapered impression copings (T), squared impression copings (S) and modified squared impression copings (MS) for implant-supported prostheses. Methods: A master cast, with four parallel implant abutment analogs and a passive framework, were fabricated. Vinyl polysiloxane impression material was used for all impressions with two metal stock trays (open and closed tray). Four groups (I, T, S and MS) were tested (n = 5). A metallic framework was seated on each of the casts, one abutment screw was tightened, and the gap between the analog of implant and the framework was measured with a stereomicroscope. The groups' measurements (80 gap values) were analyzed using software (LeicaQWin - Leica Imaging Systems Ltd.) that received the images of a video camera coupled to a Leica stereomicroscope at 100× magnification. The results were statistically analyzed with Kruskal-Wallis One Way ANOVA on Ranks test followed by Dunn's Method, 0.05. Results: The mean values of abutment/framework interface gaps were: Master Cast = 32 μm (SD 2); Group I = 45 μm (SD 3); Group T = 78 μm (SD 25); Group S = 134 μm (SD 30); Group MS = 143 μm (SD 27). No significant difference was detected among Index and Master Cast (P = .05). Conclusion: Under the limitations of this study, it could be suggested that a more accurate working cast is possible using tapered impression copings techniques and stone index. © 2013 Japan Prosthodontic Society

Comparison of the Accuracy of Plastic and Metal Stock Trays for Implant Impressions

Purpose: This in vitro study evaluated the dimensional accuracy of two impression techniques (tapered and splinted) with two stock trays (plastic and metal) for implant-supported prostheses. Materials and Methods: A master cast with four parallel abutment analogs and a passive framework were fabricated. Polyvinyl siloxane impression material was used for all impressions with two metal stock trays and two plastic stock trays (closed and open trays). Four groups (tapered plastic, splinted plastic, tapered metal, and splinted metal) and a control group (master cast) were tested (n = 5 for each group). After the framework was seated on each of the casts, one abutment screw was tightened, and the marginal gap between the abutment and framework on the other side was measured with a stereomicroscope. The measurements were analyzed with the Kruskal-Wallis one-way analysis of variance on ranks test followed by the Dunn method. Results: The mean values (+/- standard deviations) for the abutment/framework interface gaps were: master cast, 32 +/- 2 mu m; tapered metal, 44 +/- 10 mu m; splinted metal, 69 +/- 28 mu m; tapered plastic, 164 +/- 58 mu m; splinted plastic, 128 +/- 47 mu m. No significant difference was detected between the master cast, tapered metal, and splinted metal groups or between the tapered and splinted plastic groups. Conclusions: In this study, the rigidity of the metal stock tray ensured better results than the plastic stock tray for implant impressions with a high-viscosity impression material (putty). Statistically similar results were obtained using tapered impression copings and splinted squared impression copings. The tapered impression copings technique and splinted squared impression copings technique with a metal stock tray produced precise casts with no statistically significant difference in interface gaps compared to the master cast. INT J ORAL MAXILLOFAC IMPLANTS 2012;27:544-550