Inflammatory and degenerative effects of induced osteoarthritis/rheumatoid arthritis models on temporomandibular joint of rats.

OBJECTIVE: The present study compared three models of induction of osteoarthritis (OA) and rheumatoid arthritis (RA) in the temporomandibular joint (TMJ) of rats. DESIGN: The induction method was by injection of complete Freund's adjuvant (CFA) + type II bovine collagen (CII). Twenty-four adult male rats were divided into four groups (n = 6): G1: Sham, 50 µL of 0.9% sodium chloride at the base of the tail and in each TMJ; G2: OA, 50 µL CFA+CII in each TMJ; G3: RA+OA, 100 µL of CFA+CII at the base of the tail and 50 µL CFA+CII in each TMJ; G4: RA, 100 µL of CFA+CII at the base of the tail. All injections were repeated 5 days later. Twenty-three days after the first injection, the animals were sacrificed and the TMJs were submitted to histomorphometric analysis and measurement of cytokines. The Kruskal-Wallis and Dunn tests were used (alpha=0.05). RESULTS: The total thickness of the condylar cartilage increased in G2 in relation to the other groups, G3 and G4 reduced in relation to G1; and G2 and G4 reduced in relation to G2 and G3. The levels of IL-1ß, IL-6 and TNF-α increased in the three induction models compared to G1. The level of IL-10 increased in G2 compared to the other groups and reduced in G3 and G4 compared to G1. CONCLUSION: CFA+CII induced inflammation and degeneration compatible with RA (advanced chronic stage) when injected in the tail, and compatible with OA (acute stage or early disease) when injected only in the TMJ.

Biofilm formation on complete denture liners

AIM: To clinically evaluate biofilm growth on 4 liners in complete denture base surfaces of 20 geriatric patients. MATERIAL AND METHODS: Patients received new complete maxillary dentures prepared with 4 chambers (10x10x2 mm) in the tissue surface of acrylic denture base. Each of the 4 chambers was randomly filled with the following denture liners: Eversoft (M1); Kooliner (M2); GC Reline Extra Soft (M3); Elite Soft Relining (M4). Patients were randomly separated into 2 treatment groups: T1- sanitization with soft brush and dentifrice; T2- similar to T1 with daily immersion in cleansing chemical solution (Ortoform). Patients had 8 follow-up sessions over a 3-month period. The internal denture surface was stained with a dental plaque dye at each of the follow-up visits. Standardized photographs were taken, and biofilm growth was scored. Data were tabulated and submitted to Analysis of Variance. Means were compared by Tukey (p<0.05) and T tests. RESULTS: Kooliner (M2) means were significantly different from the others for both groups T1 and T2. Treatment 1 promoted higher biofilm growth scores than treatment 2. The highest score after treatment 1 was Kooliner (M2) and the lowest was Elite Soft Relining (M4). As for treatment 2, Eversoft (M1) was statistically different from Elite Soft Relining (M4). Again, Kooliner (M2) presented the highest score and Elite Soft Relining (M4) the lowest. Kooliner (M2) was statistically different from both GC Reline Extra Soft (M3) and Elite Soft Relining (M4). CONCLUSION: Of the materials and treatments studied, the best clinical selection for lower biofilm growth scores would be Elite Soft Relining (M4) with treatment 2.

Comparison of the Accuracy of Different Transfer Impression Techniques for Osseointegrated Implants.

The aim of this study was to evaluate 3 transfer techniques used to obtain working casts of implant-supported prostheses through the marginal misfit and strain induced to metallic framework. Thirty working casts were obtained from a metallic master cast, each one containing 2 implant analogs simulating a clinical situation of 3-unit implant-supported fixed prostheses according to the following transfer impression techniques: group A, squared transfers splinted with dental floss and acrylic resin, sectioned, and re-splinted; group B, squared transfers splinted with dental floss and bis-acrylic resin; and group N, squared transfers not splinted. A metallic framework was made for marginal misfit and strain measurements from the metallic master cast. The misfit between the metallic framework and working casts was evaluated with an optical microscope following the single-screw test protocol. In the same conditions, the strain was evaluated using strain gauges placed on the metallic framework. The data were submitted to one-way analysis of variance followed by the Tukey test (α = 5%). For both marginal misfit and strain, there were statistically significant differences between groups A and N (P < .01) and groups B and N (P < .01), with greater values for group N. According to the Pearson test, there was a positive correlation between the misfit and strain variables (r = 0.5642). The results of this study showed that the impression techniques with splinted transfers promoted better accuracy than the nonsplinted technique, regardless of the splinting material used.

Stress evaluation of implant-abutment connections under different loading conditions: a 3D finite element study.

This study evaluated the effects of axial and oblique occlusal loading on implant-supported partial dentures with different connection systems (external hexagon, internal hexagon, and Morse taper). Upon axial loading, all systems presented similar stress values. Stress values increased under oblique loading. Stress distribution changed for some of the internal connection structures. It can be concluded that oblique load increases stress on bone structures and prosthetic components. Internal connection system implants present more favorable stress distribution patterns than do external connection system implants.

Influence of the casting technique and dynamic loading on screw detorque and misfit of single unit implant-supported prostheses.

OBJECTIVE: This study aimed to evaluate the influence of the casting procedure and cyclic loading of prosthetic frameworks on detorque of prosthetic screws and marginal misfit of single unit implant-supported prostheses. MATERIALS AND METHODS: Twenty specimens were obtained, each one consisting of a set of an implant (external hexagon 3.75 × 13 mm - Branemark type), a prosthetic abutment (entirely calcinable or overcasted UCLA) and a prosthetic screw. After the specimens were obtained, the prosthetic screws were tightened with 30 Ncm torque and released 24 h later in order to evaluate initial detorque. The screws were retightened and marginal gaps were assessed. All specimens were submitted to 10(6) loading cycles, performed with 2 Hz frequency and 130 N load. The specimens were re-evaluated for marginal misfit and detorque after the mechanical loading (final marginal misfit/final detorque). The results were submitted to analysis of variance for repeated measurements, followed by Tukey HSD test (α = 0.05). RESULTS: No statistically significant differences were found on detorque values of the prosthetics screws for all groups and intervals evaluated (p = 0.8922). The entirely calcinable abutments showed higher initial marginal misfit compared to the overcasted ones (p = 0.0438). There was no statistically significant difference on marginal misfit before and after mechanical loading for both groups (p > 0.05). CONCLUSIONS: It can be concluded that the overcasted abutments showed lower misfit values when compared to the entirely casted abutments. No difference was observed on detorque values of prosthetic screws. After mechanical loading there was no difference on marginal misfit and detorque between the groups.

Adhesive bonding of resin cements to cast titanium with adhesive primers.

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 µ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

The influence of master cast technique on the cast precision of implant-retained fixed prostheses.

The aim of this study was to evaluate the precision of three different mold filling techniques in order to obtain a cast simulating a three-unit, implant-retained, fixed prosthesis. Thirty casts (n = 10) were obtained using three different mold filling techniques. Group 1 used a unique fulfillment technique, Group 2 used a two-step fulfillment technique, and Group 3 used a latex cylinder technique. Using a metallic matrix, a titanium substructure was created to simulate a three-unit fixed prosthesis used as reference to evaluate the marginal misfit and tension forces in each cast. The vertical misfit was measured by an optical microscope with an increase of 120X and by an analysis unit using the one-screw test. The tension was quantified using strain gauges. The strain results showed a statistical difference between Group 3 and the other groups. The Tukey test showed no difference between the different treatment groups (p = 0.05). All three techniques were deemed efficient; however, considering that the cylinder latex technique induced less force toward the implants, it is the preferable technique for daily clinical practice.

Adhesive bonding of resin cements to cast titanium with adhesive primers

The purpose of this study was to evaluate the effects of adhesive primer applications on the bond strength of resin cements to cast titanium. Four adhesive primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - and their respective resin cements - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - were tested. Cast plates were prepared from titanium ingots (n=6 specimens/cement) and had their surfaces airborne-particle abraded with Al2O3 (50 μ m). Three resin cement cylinders were built on each bonded titanium surface, using a cylindrical translucent tubing mold and were subjected to micro-shear testing. Data were analyzed statistically by two-way ANOVA and Tukey's post-hoc test (α=0.05). The application of Metal Primer II and Ceramic Primer resulted in significant higher bond strength for Link Max and RelyX Unicem resin cements, respectively, than nonuse of adhesive primers. Panavia F 2.0 and RelyX ARC yielded high bond strength means with or without adhesive primers. The use of adhesive primers might increase the bond strength to cast titanium depending on the resin cement used.

O objetivo deste estudo foi avaliar o efeito da aplicação de primers na resistência de união de cimentos resinosos ao titânio. Quatro primers - Metaltite, Metal Primer II, Alloy Primer and Ceramic Primer - e seus respectivos cimentos resinosos - Bistite II DC, Link Max, Panavia F 2.0, RelyX Unicem and RelyX ARC - foram testados. Placas de titânio foram preparadas a partir da fundição de lingotes (n=6 espécimes/cimento) e as superfícies dessas placas foram jateadas com partículas de Al2O3 (50 μ m). Três cilindros de cimento resinoso foram construídos em cada placa de titânio, utilizando moldes transparentes com formato de cilindro e foram submetidos ao teste de microcisalhamento. Os dados foram analisados pela ANOVA (dois fatores) e teste de Tukey (α=0,05). A aplicação do Metal Primer II e do Ceramic Primer resultou no aumento significativo da resistência de união para os cimentos resinosos Link Max e RelyX Unicem, respectivamente. Os cimentos Panavia F 2.0 e o RelyX ARC mostraram altos valores de resistência de união com ou sem o uso dos primers. A aplicação dos primers pode aumentar a resistência de união dos cimentos resinosos ao titânio, dependendo do tipo de cimento resinoso utilizado.

Photoelastic analysis of the distribution of stress in different systems of overdentures on osseous-integrated implants.

OBJECTIVE: The aim of this study was to evaluate the distribution of generated stress around implants and adjacent bone tissue using different implant-retained overdenture designs through photoelastic analysis. METHODS: Over an edentulous human mandible, achieved from a human model, 2 or 4 microunit analog abutments were embedded (Master; Conexao Systems Prosthodontics, São Paulo, Brazil), settled in the interforaminal region. Three models of photoelastic resin (Araltec Chemicals Ltda, Hunstman, Guarulhos, São Paulo, Brazil), with 2 or 4 incorporated implants and microunit abutments, were obtained from molds using silicone for duplication. Inclusion, finishing, and polishing procedures were applied on the frameworks. This study was based on 3 different mechanisms of implant-retained mandibular overdentures: O'ring (GI), bar-clip (GII) (both with 2 implants), and their association (GIII) (with 4 implants). After the adaptation of each overdenture system on the photoelastic models, 100-N alternate occlusal loads were applied on back-side and front-side regions. The photoelastic analysis was made with the aid of a plain polariscope linked to a digital camera, Sony Cybershot α100, which allowed visualization of the fringes and registration of images on digital photographs. RESULTS: The results demonstrated higher tension concentrated over the GIII, with a flat distribution of stress to the posterior ridge and overload on the posterior implants. GI showed the smaller stress level, and GII, intermediate level; there was distribution of stress to the posterior ridge in these 2 groups. CONCLUSION: The use of bar attachment proved to be a better alternative, because it showed a moderate level of tension with a more uniform stress distribution and possessed higher retention than did the ball system.

Solução protética para implantes mal posicionados: relato de caso clínico / Prosthetic solution for misplaced implants: a case report

Reabilitações protéticas sobre implantes ainda é um desafio para Odontologia. Existem situações em que os implantes são colocados em locais não compatíveis com o posicionamento dos dentes no arco, sendo necessário utilizar compensações protéticas capazes de corrigir essa dificuldade. Este trabalho tem como objetivo, relatar um caso clínico que apresenta uma opção protética para compensar o mau posicionamento dos implantes, pelo uso de uma mesoestrutura metálica. O paciente apresentava uma deformação óssea na região anterior de maxila onde foram instalados quatro implantes, posicionados de tal forma que os acessos aos parafusos protéticos ocorriam em áreas estética e biomecanicamente desfavoráveis. Portanto, foi planejado a confecção de uma mesoestrutura metálica, alterando a região de acesso aos parafusos protéticos, o que proporcionou ótimo resultado estético e satisfação do paciente.

Prosthetic rehabilitation on implants is still a challenge for Dentistry. There are situations where the implants are placed in locations that are not compatible with the positioning of the teeth in the arch, prosthetic compensation is necessary to be able to fix this problem. This study aims, report a clinical case that presents a prosthetic option to compensate the poor positioning of implants, by using a metallic mesostructure.The patient had a bone deformation in the anterior maxilla where four implants were installed, positioned so that access to prosthetic screws occurred in areas aesthetics and biomechanically unfavorable. So it was planned the construction of a metallic mesostructure, changing the area of access to prosthetic screws, which provided excellent aesthetic results and patient satisfaction.

Análise da influência de diferentes técnicas de preenchimento do molde com gesso na precisão de modelos de próteses fixas implanto-retidas / Evaluation of master cast techniques influence of implant fixed prostheses cast precision

Objetivo: Este estudo teve por objetivo avaliar a precisão de três técnicas de preenchimento do molde com gesso para obtenção de modelos de trabalho a partir de um modelo mestre simulando uma situação clínica de uma prótese fixa implanto-retida de três elementos. Materiais e métodos: Foram obtidos trinta modelos (n = 10) a partir do modelo mestre, por meio de três técnicas de preenchimento do molde com gesso. Assim, o Grupo 1 foi obtido pela técnica de preenchimento único (PU); o Grupo 2, pelo preenchimento do molde com gesso em duas porções (DP); o Grupo 3, utilizando-se a técnica do cilindro de latex (CL). Sobre a matriz metálica foi obtida uma infraestrutura fundida em titânio comer-cialmente puro simulando uma prótese fixa implanto-retida de três elementos, utilizada como referência para a avaliação de desajustes verticais em cada modelo. O desajuste vertical foi avaliado segundo a técnica do parafuso único. Para a análise dos resultados foi aplicada a análise de variância, seguida do teste de Tukey. Resultados: De acordo com os resultados obtidos, observou-se maior valor médio entre as amostras do grupo em que o molde foi preenchido com gesso pela técnica do preenchimento único (média = 0,14), ao passo que as amostras dos grupos 2 e 3 apresentaram os mesmos valores médios (média = 0,10). Porém, de acordo com o teste de Tukey, não houve diferença estatística entre os três diferentes grupos de tratamento. Conclusão: Assim, pode-se afirmar que as três técnicas foram eficientes, sendo, de acordo com a praticidade, a mais indicada a técnica de preenchimento único.

Effect of accelerated aging on permanent deformation and tensile bond strength of autopolymerizing soft denture liners.

PURPOSE: The aim of this study was to evaluate the effect of different accelerated aging times on permanent deformation and tensile bond strength of two soft chairside liners, acrylic resin (T) and silicone (MS) based. MATERIALS AND METHODS: Different specimens were made for each test of each reliner. The specimens (n = 10) were submitted to accelerated aging for 2, 4, 8, 16, 32, and 64 cycles. Tensile bond strength testing was performed at a crosshead speed of 5 mm/min and permanent deformation with a compressive load of 750 gf. Data were submitted to Mann-Whitney test to compare the materials at different times, and Kruskal-Wallis and Dunn tests were used for comparing aging intervals within a given reliner. RESULTS: MS presented a lower percentage of permanent deformation (p < 0.0001) and higher tensile bond strength (p < 0.0001) than T in all time intervals and was not affected by the accelerated aging process, which reduced the permanent deformation and increased tensile bond strength of T (p < 0.05). CONCLUSION: MS presented lower permanent deformation and higher tensile bond strength than T. Although T presented changes in those properties after accelerated aging, both materials might be suited for long-term use.

Radiographic inspection of porosity in pure titanium dumbbell castings.

BACKGROUND: Titanium frameworks are frequently indicated for implant supported prostheses; however, voids are usually encountered inside cast titanium. OBJECTIVE: This study aimed to confirm the efficacy of a radiographic technique for inspection of porosity in commercially pure titanium castings with different diameter. MATERIALS AND METHODS: Sixty dumbbell rods (n=20) with a central 1.5, 2.0 and 3.5mm diameter were prepared by lost-wax casting. Cast specimens were finished and polished and submitted to radiographic examination (90kV, 15mA, 0.6s and 10-13mm of distance) using periapical film. The radiographs were visually analysed for the presence of porosity in the extension of the dumbbell or in the central portion of the rods. Data were submitted to Pearson Chi-square test (5%). RESULTS: The tested radiographic method proved to be suitable for the evaluation of cast frameworks. Internal porosities were observed in most of the specimens (91.7%) (p=0.0005); however, only 20% occurred on the central portion of the rods (p=0.612). CONCLUSION: Internal porosities can be visualised through radiographs and occur mostly in small diameter structures. The radiographic evaluation of metal structures can improve the quality of frameworks and thereby potentially increase the longevity of the rehabilitation.

Implant-supported titanium framework: photoelastic analysis before and after spark erosion procedure

Aim: This study used a photoelastic analysis to evaluate the passive fit of titanium cast laserwelding frameworks before and after spark erosion procedure. Methods: A stainless steel castwas used in order to reproduce a human mandible. Five Multi-Unit abutment analogs wereattached to this cast and 6 frameworks were produced in commercial pure titanium. The cast wasmolded and a photoelastic matrix was produced incorporating 5 dental implants with Multi-Unitabutments. All samples were subjected to a laser welding. The precision of adjustments within arange of 0.5 ìm was evaluated under microscope observation. The best fitted framework wasselected and subjected to a photoelastic analysis (Group I). The tightening of the screws was in 3predetermined sequences (1,2,3,4,5/ 5,4,3,2,1/ 3,2,4,1,5). Then the same framework wassubjected to a refinement by spark erosion technique (Group II) and evaluated by photoelasticanalysis. Results: The sequence (3,2,4,1,5) achieved better results in both groups. A largernumber of fringes were observed around the median implants in all sequences in both groups.Conclusions: The titanium cast laser welded frameworks processes associated with spark erosionprocedure improves significantly the marginal framework adaptation and is effective for its passive fit.

The service life of implant-retained overdenture attachment systems.

STATEMENT OF PROBLEM: Implant-retained overdentures are a treatment option for patients who are not satisfied with conventional complete dentures. Although implant-retained overdentures are widely used, little data are available or provided by implant manufacturers about retentive strength and wear of attachments. PURPOSE: The purpose of this study was to evaluate retentive strength and fatigue resistance of 4 overdenture bar-and-clip attachment systems. MATERIAL AND METHODS: Forty bar-and-clip attachment system specimens were tested (n=10): Conexão Bar Clip (polymer clip), Sterngold Hader Bar (polymer clip), 3i Gold Hader Type Clip (metal clip), or SIN Clipo (metal clip). Specimens immersed in artificial saliva were tested to 5500 cycles at 0.8 Hz using a servohydraulic universal testing machine. Retention strength values (N) were recorded initially and after 1100, 2200, 3300, 4400, and 5500 insertion and removal cycles during the tensile test using a speed of 1 mm/min and a load cell of 1 kN. Data were submitted to a 2-way repeated-measures ANOVA and the Tukey A post hoc test (alpha = .05). RESULTS: An increase in retention strength values was observed during the fatigue test after 5500 cycles of insertion and removal. No significant difference in retentive strength was observed in the groups using polymer clips (Conexão Bar Clip and Sterngold Hader Bar) (P=.729); the same occurred with metal clip systems (SIN Clipo and 3i Gold Hader Type Clip) (P=.068). The SIN Clipo system demonstrated the smallest retention strength values, which were significantly different from the other 2 attachment systems, the Sterngold Hader Bar (P<.01) and the Conexão Bar Clip (P<.01). Although the 3i Gold Hader Type Clip did not differ significantly, in terms of retentive strength, from the Sterngold Hader Bar (P=.258), its retentive strength was significantly lower than the retentive strength of the Conexão Bar Clip system (P=.030). CONCLUSIONS: The systems evaluated demonstrated satisfactory retention for all time periods tested, as retention strengths from 5 to 7 N should be sufficient to stabilize overdentures. No component fracture or compromise in retention was found for any of the systems tested.

Correlação entre o desajuste marginal e a tensão gerada sobre os implantes / Correlation between marginal misfit and strains around implants

A indução de tensões ao implante e ao tecido ósseo peri-implantar pode ser responsável pela reabsorção tecidual e pela perda do implante. Próteses com o mínimo desajuste marginal são desejadas, acreditando-se na geração de menores valores de tensão às fixações .No entanto, não se tem certeza desta correlação, uma vez que a literatura não apresenta resultados confiáveis que venham a elucidar tal aspecto. Assim, o objetivo deste trabalho foi verificar se existe correlação entre os valores de desajuste marginal e de tensão gerados às fixações pelo parafusamento de infraestruturas implanto-retidas. Foram obtidas dez infraestruturas em titânio fundido, utilizando-se matriz metálica contendo dois implantes conectados a pilares cônicos para construções múltiplas. As infraestruturas foram aleatoriamente avaliadas quanto aos desajustes marginais mediante o teste do parafuso único e observação em microscópio ótico(120X). As tensões nas fixações foram avaliadas por extensometria. A média de desajuste marginal foi 118,07(58,61) μm e a média de tensão, 580,06 (253,93) gf.O teste de Pearson foi utilizado, mostrando não haver correlação entre desajuste marginal e tensão (-0,072),com p = 0,842. A presença e a intensidade do desajuste marginal, por si só, não são indicadores seguros no prognóstico da geração de tensões às fixações

Influence of prosthetic screw material on joint stability in passive and non-passive implant-supported dentures.

OBJECTIVES: This study evaluated the influence of prosthetic screw material on joint stability in implantsupported dentures at two levels of fit. METHODS: Ten mandibular implant-supported dentures were fabricated. Twenty cast models were fabricated using these dentures. Four groups (n=10) were tested, according to the vertical fit of the dentures [passive and non-passive] and prosthetic screw materials [titanium (Ti) or gold (Au) alloy]. The one-screw test was performed to quantify the vertical misfits using an optic microscope. The loosening torque for the prosthetic screws was measured 24 hours after the tightening torque (10 Ncm) using a digital torque meter. Data were analyzed by two-way ANOVA and Tukey's test (alpha=0.05). RESULTS: Overall, dentures with passive fit and Ti screws resulted in significantly higher loosening torque of the prosthetic screws (p<0.05). No significant interaction was found between fit level and screw material (p=0.199). The prosthetic screw material and fit of implant-supported dentures have an influence on screw joint stability. Ti screws presented higher joint stability than Au screws and minimum of misfit should be found clinically to improve the mechanical behavior of the screw joint.

Effects of thermocycling on the tensile bond strength of three permanent soft denture liners.

PURPOSE: This study investigated the effect of in vitro accelerated aging reproduced with thermocycling on the bond strength of three commercially available permanent denture soft liners (PermaSoft, Dentuflex, Ufi-gel) with one heat-polymerized polymethyl methacrylate resin denture base (QC-20) by tensile test. MATERIAL AND METHODS: Ten specimens were prepared for control and test groups of each material for a total of 60 specimens. All controls were stored in water (37 degrees C) for 24 hours before testing. All test groups received 3000 thermal cycles consisting of 1 minute at 5 degrees C and 1 minute at 65 degrees C. All specimens were submitted to a tensile test using a universal testing machine at a crosshead speed of 5 mm/min. Results were statistically analyzed (ANOVA, p < or = 0.05, Tukey's post-hoc test). RESULTS: The mean bond strength of control specimens was (MPa): 0.32 (Ufi-gel), 0.49 (PermaSoft), and 1.19 (Dentuflex). There was no statistical difference (p > 0.05) between Ufi-gel and PermaSoft, but both were statistically different (p < 0.05) when compared to Dentuflex. After thermocycling, the mean bond strength was (MPa): 0.18 (Ufi-gel), 0.81 (PermaSoft), and 3.32 (Dentuflex). All materials were statistically different (p < 0.05). Ufi-gel had the lowest value and Dentuflex the highest in both control and test groups. Dentuflex presented only adhesive failure; in the remaining groups, there was no predominant failure mode, except Ufi-gel control with no adhesive failure. CONCLUSIONS: Despite presenting greater bond strength, thermocycling had a deleterious effect in Dentuflex; Ufi-gel may be adequate for short-term use.

Análise das tensões induzidas nos implantes quando submetidos ao parafusamento de próteses parciais com e sem intermediários / Analysis of stress induced in implants when submitted to the screwing of partial prosthesis with and without abutments

Tensões ao implante e ao tecido ósseo peri-implantar podem causar reabsorção e perda de componentes. A magnitude das tensões pode variar com o uso pilares intermediários entre a prótese e os implantes. Assim, o objetivo deste trabalho foi verificar as tensões induzidas aos implantes quando submetidos ao torqueamento de infraestruturas protéicas com e sem o uso de pilar intermediário. Vinte infraestruturas em titâneo (n=10) foram obtidas por fundição a partir de matriz metálica contendo dois implantes, simulando prótese fixa de três elementos. Dez peças foram confeccionadas utilizando copings calcináveis tipo UCLA diretamente sobre os implantes. Outras dez foram confeccionadas sobre pilares cônicos intermediários para construções múltiplas. As tensões foram aferidas após o torqueamento de cada estrutura mediante o uso de extensômetros calibrados. A média de tensão no grupo UCLA foi 665,35 (173,99) gf e no grupo minipilar cônico foi 580,06 (253,93) gf. O teste t de Student foi utilizado para a comparação intergrupos. Não houve diferença estatística para os valores de tensão entre os dois grupos (p > 0,3924). O uso do pilar intermediário em infraestruturas de três elementos em Ti c.p. fundido não reduziu as tensões induzidas aos implantes.

Técnicas simplificada de moldagem de implantes e tecidos peri-implantares simultaneamente / Simplifyed simultaneous impression techniqhe for implants and peri-implant tissues

O presente artigo descreve um método alternativo de moldagem de transferência na qual possibilita copiar os implantes bem como o contorno dos tecidos peri-implantares de forma simultânea. Para isso, utiliza-se resina composta fluída fotopolimerizável com o intuito de se reproduzir os tecidos gengivais no modelo funconal. Esta técnica tem como vantagem, a reprodução do perfil de emergência, fundamental na estética final da restauração.

The present article described an alternative impression technique for tranfer that is possible to simultaneous copy implants and gingival contours. For that, it used a flow composite resin, with the purpose to reestablish the gingival tissues to functional cast. The advantages to this technique is correctly replayed the emergency contour, considered very important in the final esthetic of the prosthetic restoration.