Effect of splinting in accuracy of two implant impression techniques.

Because there is no consensus in the literature about the need for a splint between copings, the aim of this study was to evaluate, in vitro, the accuracy of 2 impression techniques for implant-supported prostheses. A master cast was fabricated with four parallel implant abutment analogs and a passive framework. Two groups with 5 casts each were formed: Group 1 (squared impression copings with no splint: S) and Group 2 (splinted squared impression copings, using metal drill burs and Pattern resin: SS). The impression material used was polyvinyl siloxane with open trays for standard preparation of the casts. For each cast, the framework was positioned, and a titanium screw was tightened with 10 N·cm torque in analog A, after which measurements of the abutment-framework interface gaps were performed at analogs C and D. This process was repeated for analog D. These measurements were analyzed using software. A one-way analysis of variance (ANOVA) with a confidence interval of 95% was used to analyze the data. Significant differences were detected between S and SS in relation to the master cast (P ≤ 0.05). The median values of the abutment-framework interface gaps were as follows: master cast: 39.64 µm; squared impression copings with no splint: 205.86 µm; splinted squared impression copings: 99.19 µm. Under the limitations of this study, the technique presented for Group 2 produces better results compared with the technique used for Group 1.

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.

O design inteligente e a estratificação biomimética em restaurações diretas posteriores: consolidando a era pós-amálgama / Rational design and biomimetic layering of posterior composite restorations: consolidating the postamalgam era

No campo da dentística restauradora, muitas conquistas têm sido alcançadas, principalmente em relação à crescente conscientização dos pacientes quanto à possibilidade de se obterem restaurações mais funcionais e estéticas. O grande dilema tem sido como raciocinar clinicamente com esses novos conceitos, ou seja, modificar a abordagem antiga, que era baseada na ausência da verdadeira união. Quais conceitos clássicos devem permanecer vigentes nesse novo contexto? Mimetizar, em ciência, envolve permitir a cópia de um modelo que, na área odontológica, sem dúvida, é o dente intacto. Este artigo aborda a associação desse conceito com a técnica e a seleção dos materiais na prática clínica.

The increased awareness of patients for more functional and esthetic restorations led to a number of archievements that occurred in Restorative Dentistry. A major concern is how to clinically thinking on these new concepts, changing the old approach which was based on the lack of true adhesion. Which classical concepts should be maintained in this new context? Mimicking in science, involves a process of copying a model that, in the dental field, is in most cased an intact tooth. This article discusses the association of this concept with the technique and selection of materials in clinical practice.

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 Μm; tapered metal, 44 ± 10 Μm; splinted metal, 69 ± 28 Μm; tapered plastic, 164 ± 58 Μm; splinted plastic, 128 ± 47 Μm. 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.

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 (I), 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 3100 magnification. The results were evaluated statistically (analysis of variance, Holm-Sidak method, α = .05). RESULTS: The mean abutment/framework interface gaps were: master cast = 31.63 µm; group I = 45.25 µm; group S = 96.14 µm; group MS = 51.20 µm. 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.

Comparison of impression techniques and materials for an 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 µm (SD 2.16); SI, 38.03 µm (SD 9.29); ASI, 46.80 µm (SD 8.47); SE, 151.21 µm (SD 22.79); and ASE, 136.59 µm (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.

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 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. 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 3100 magnification. The results were analyzed statistically (t test). RESULTS: The mean values of abutment/framework interface gaps were: master cast = 32 Μm (SD 2), group D =165 Μm (SD 60), and group M = 69 Μm (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.

Precisão das técnicas de moldagem para próteses implantossuportadas / Accuracy of impression techniques for an osseointegrated implant-supported prosthesis

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...

Técnicas de moldagem em prótese sobre implantes / Impressions techniques for dental implants

A obtenção de um modelo de trabalho fiel em implantodontia está relacionada principalmente às técnicas de moldagem e aos materiais utilizados. O objetivo desta revisão de literatura é apresentar os materiais e as técnicas de moldagem mais precisas utilizados em prótesesimplantossuportadas. Com base nos artigos revisados, verifica-se que a técnica de moldagem mais precisa é a de arrasto com transferentes quadrados unidos por meio de barras pré-fabricadas de resina auto ou fotopolimerizável associada a um material elastomérico (poliéter ou silicona por adição).

The accuracy of dental implants is related to impression materials and dental impression techniques. This paper presents, according to scientific literature, the most precise impression materials and dental impression techniques used in implant prosthodontic rehabilitations. Based on the reviewed manuscripts, an elastomeric material (polyether and polyvinyl siloxane) associated to an open-tray pick-up impression technique (square transfer copings splinted) should be used in implant-supported dental prosthesis.

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 microm. With the conventional pouring technique, the mean gap values were 116.97 microm for the tapered group, 57.84 microm for the squared group, and 73.17 microm for the squared splinted group. With pouring using latex tubes, the mean gap values were 65.69 microm for the tapered group, 38.03 microm for the squared group, and 82.47 microm for the squared splinted group. With pouring after joining the analogs with acrylic resin, the mean gap values were 141.12 microm for the tapered group, 74.19 microm for the squared group, and 104.67 microm for the squared splinted group. No significant difference was detected among Index, square/latex 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.

Carga imediata e carga tardia em overdentures sobre implante / Immediate loading and delayed loading on implant overdentures

A estabilidade primária e o período de cicatrização sem carga dos implantes dentais por aproximadamente 3 a 6 meses têm sido considerados, por anos, importante para permitir a osseointegração dos implantes. Entretanto, estudos recentes têm encorajado o encurtamento do período de cicatrização e o carregamento imediato tem sido proposto para pacientes completamente edêntulos. Altas taxas de sucesso são geralmente relatadas no carregamento imediato. Apesar das evidências, muitas controvérsias ainda existem sobre aconfiabilidade dos dados relatados, freqüentemente devido ao insuficiente acompanhamento, inadequado tamanho da amostra e falta decritérios de sucesso bem definidos. O objetivo dessa investigação foi revisar a literatura para avaliar estudos sobre o carregamento imediato ou precoce de implantes em mandíbulas e maxilas edêntulas e reabilitadas com overdentures implanto-suportadas. As taxas de sucesso encontradas na literatura odontológica sugerem que o carregamento imediato ou precoce de implantes dentais pode ser aplicado sob condições controladas.

The primary stability and the healing period without loading of dental implants for approximately 3 to 6 months have been considered for years important to allow osseointegration of dental implants. However, recent studies have encouraged a shortening of the healing period and immediate loading has been proposed for completely edentulous patients. High survival rates were generally reported in the immediate loading. In spite of evidences, much controversy still exists over the reliability of the reported data, frequently due to insufficient follow-up, inadequate sample size and lack of well defined success criteria. The objective of this investigation was to review the literature to evaluate studies about early and immediate loading of implants placed in the edentulous mandible and maxilla and rehabilitated with implant-supported overdentures. The success rates achieved in dental literature suggest that immediate orearly loading of dental implants can be applied under controlled conditions.