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Purpose: To evaluate biologic and prosthetic outcomes of implant-supported mandibular full-arch fixed prostheses treated with the All-on-4 treatment concept after 7 years. Materials and Methods: Patients were selected to receive full-arch fixed immediate prostheses supported by four implants up to 72 hours after surgery. The following biologic aspects were evaluated: Plaque Index (PI) and Bleeding Index (BI), implant stability by resonance frequency, and marginal bone loss (MBL) measured with the aid of periapical radiographs. The prosthetic complications evaluated were related to screw loosening, framework or acrylic teeth fractures, or fractures of implants. The means of implant stability and MBL were subjected to analysis of variance and the Tukey test (P < .05). For PI and BI, the Friedmann test was used (P < .05). Results: Sixteen patients (12 women and 4 men; mean age: 59.1 years) received 64 implants, and in all patients, two implants were positioned axially at the incisor region and two distally tilted implants at the region of the second premolars or molars. Patients were evaluated immediately after surgery and at 1, 2, and 7 years. Fifteen patients attended the recall after 2 years; one patient could not attend the scheduled follow-up visit and was excluded from the sample. In the 7-year evaluation, the sample size decreased to 12 patients; one could not attend because of a severe disease, and two were deceased. The cumulative implant survival rate was 100%. There was a significant (P < .0162) decrease in PI at the 1- and 7-year evaluations (71.87% and 47.92%, respectively), while the BI was the same at 1 and 7 years (43.75%). There was no statistical difference in MBL (P = .12) and implant stability (P = .48) between axial and tilted implants (P = .48). The survival rate of prostheses was 100%. The following technical complications were observed: tooth fracture occurred in one patient (6.25%); loosening of prosthetic screws and abutments were observed in three patients (18.75%); after 5 years, three patients (18.75%) had changed the denture acrylic teeth because of the replacement of the removable total maxillary prostheses with fixed implant prostheses. Conclusion: For the 12 patients who attended the recall after 7 years, implant loss was not found, the implant stability was high, MBL was low, and prosthetic complications were easily solved. Thus, it can be concluded that rehabilitation with implant-supported mandibular full-arch fixed prostheses with four implants has proved to be a treatment with a high survival rate.

BACKGROUND To evaluate the influence of thermal and mechanical fatigue on the shear bond strength of different all-ceramic cores and veneering porcelain interfaces. MATERIAL AND METHODS All-ceramic systems tested were lithium disilicate and zirconia veneered by layering technique. Sixty specimens (n=20) were subjected to shear bond strength. Ten of them were thermal and mechanical cycled. Fracture analysis was performed with stereomicroscopy and scanning electron microscopy. Energy dispersive X-ray spectroscopy analysis was performed across core/veneer interfaces. RESULTS Thermal and mechanical cycling did not influence on bond strength. However, there was significant difference among systems (

The biomechanical properties of post systems may become more important as the amount of remaining tooth structure decreases, thus different materials may influence the characteristic strength of fatigued endodontically treated teeth.The purpose of this study was to assess the characteristic strength and probability of survival of endodontically treated teeth restored with different intraradicular post systems.Forty human maxillary canines with similar root lengths were randomly divided into 4 groups (n=10): cast post and core, stainless-steel prefabricated post, carbon-fiber post, and glass-fiber post. Cores and metallic crowns were fabricated for all specimens. Restored teeth were exposed to mechanical fatigue (250,000 cycles) in a controlled chewing simulator. Each intact specimen was mounted in a special device and aligned at a 45-degree angle to the long axis of the tooth. A universal testing machine was used to apply a static load at a crosshead speed of 0.5 mm/min until specimen failure. The maximum value was recorded in newtons (N). Probability Weibull curves (2-sided 90% confidence bounds) were calculated for each group, and a probability of survival as a function of load at failure was plotted for the groups.A significantly higher characteristic strength was observed for groups carbon-fiber post (755.82 N) and cast post and core (750.6 N) (P.05) compared with glass-fiber post (461.35 N) and stainless-steel prefabricated post (524.78 N) groups. All the roots in the cast post and core group demonstrated catastrophic fracture, whereas the remaining groups had no root fractures.Prefabricated posts made of glass fiber and stainless steel showed significantly lower characteristic strength and probability of survival than cast post and core, whereas crowns with carbon-fiber posts presented a single load similar to the fracture values of cast posts.

Objective.The purpose of this study was to histologically evaluate the effect of low-level laser (LLL) on the healing of critical size defects (CSD) in rat calvaria, filled with autogenous or inorganic bovine bone grafts.Methods.Sixty rats were divided into 6 groups(n=10): C (control—filled with blood clot), LLL (low-level laser—GaAlAs,λ780 nm, 100 mW, 210 J/cm2,Φ0.05 cm2; 6 J/point), AB (autogenous bone), ABL (autogenous bone + low-level laser), OB (inorganic bovine bone), and OBL (inorganic bovine bone + LLL).Material and Methods.The animals were killed after 30 days. Histological and histometric analyses were performed by light microscopy.Results.The groups irradiated with laser, LLL (47.67% ± 8.66%), ABL (39.15% ± 16.72%), and OBL (48.57% ± 28.22%), presented greater area of new bone formation than groups C (9.96% ± 4.50%), AB (30.98% ± 16.59%), and OB (11.36% ± 7.89%), which were not irradiated. Moreover, they were significantly better than group C (Kruskal-Wallis test followed by Dunn test,P<0.05).Conclusion.The laser accelerated the healing of bone defects and the resorption of particles of the graft material.

Endodontically treated teeth are known to have reduced structural strength. Glass fiber posts may influence fracture resistance and should be evaluated.The purpose of this study was to evaluate the influence of glass fiber post length on the fracture resistance of endodontically treated teeth.Forty intact human maxillary canines were selected and divided into 4 groups, the control group consisting of teeth restored with a custom gold cast post and core, with a length of two-thirds of the root. Other groups received prefabricated glass fiber posts in different lengths: group 1/3, removal of one-third of the sealing material (5 mm); group 1/2, removal of one-half of the sealing material (7.5 mm); and group 2/3, removal of two-thirds of the sealing material (10 mm). All the posts were cemented with resin cement, and the specimens with glass fiber posts received a composite resin core. All the specimens were restored with a metal crown and submitted to a compressive load until failure occurred. The results were evaluated by 1-way ANOVA, and the all pairwise multiple comparison procedures (Tukey honestly significantly difference test) (α=.05).The ANOVA showed significant differences among the groups (P.002). The Tukey test showed that the control group presented significantly higher resistance to static load than the other groups (control group, 634.94 N; group 1/3, 200.01 N; group 1/2, 212.17 N; and group 2/3, 236.08 N). Although teeth restored with a cast post and core supported a higher compressive load, all of them fractured in a catastrophic manner. For teeth restored with glass fiber posts, the failure occurred at the junction between the composite resin core and the root.The length of glass fiber posts did not influence fracture load, but cast post and cores that extended two-thirds of the root length had significantly greater fracture resistance than glass fiber posts.

The aim of this study was to evaluate the tensile resistance of mineralized and demineralized bones. Twelve mice were used. Specimens were collected and divided into groups 1 and 2, mineralized and demineralized calvarial bone, and groups 3 and 4, mineralized and demineralized femoral bone. There was not a statistically significant difference (analysis of variance) between the regions; however, when comparing the demineralized and mineralized groups, a statistically significant difference (Student test) for the mineralized group was noticed.

Since the introduction of glass fiber posts, irreversible vertical root fractures have become a rare occurrence; however, adhesive failure has become the primary failure mode.The purpose of this study was to evaluate the push-out bond strength of glass fiber posts cemented with different luting agents on 3 segments of the root.Eighty human maxillary canines with similar root lengths were randomly divided into 8 groups (n=10) according to the cement assessed (Rely X luting, Luting and Lining, Ketac Cem, Rely X ARC, Biscem, Duo-link, Rely X U100, and Variolink II). After standardized post space preparation, the root dentin was pretreated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into post spaces with a spiral file and applied to the post surface that was seated into the canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections. The push-out test was performed at a speed of 0.5 mm/min until extrusion of the post occurred. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05).ANOVA showed that the type of interaction between cement and root location significantly influenced the push-out strength (P.05). The highest push-out strength results with root location were obtained with Luting and Lining (S3) (19.5 ±4.9 MPa), Ketac Cem (S2) (18.6 ±5.5 MPa), and Luting and Lining (S1) (18.0 ±7.6 MPa). The lowest mean values were recorded with Variolink II (S1) (4.6 ±4.0 MPa), Variolink II (S2) (1.6 ±1.5 MPa), and Rely X ARC (S3) (0.9 ±1.1 MPa).Self-adhesive cements and glass ionomer cements showed significantly higher values compared to dual-polymerizing resin cements. In all root segments, dual-polymerizing resin cements provided significantly lower bond strength. Significant differences among root segments were found only for Duo-link cement.

To assess the dentine/fibreglass-bonded interface by scanning electron microscopy and the push-out bond strength of four luting cements.Forty root-filled human canines, with similar root lengths, were restored with fibreglass posts and randomly divided into four groups according to the cements employed (CG Gold Label I, RelyX ARC, BisCem and RelyX U100). After standardized post-space preparation, the root dentine was pre-treated for dual-polymerizing resin cements and untreated for the other cements. The mixed luting cement paste was inserted into root canals with a spiral filler and applied to the post-surface that was seated into the root canal. After 7 days, the teeth were sectioned perpendicular to their long axis into 1-mm-thick sections and submitted to a push-out test (1 mm min(-1)). Statistical analyses were carried out by two-way anova and Tukey's tests (P0.05).The bond strength was significantly affected by the type of cement (P0.001) and by the longitudinal region of the root canal (P0.031). All cements exhibited gaps at the dentine/cement interface.The self-adhesive materials and the glass ionomer cements had the highest push-out bond strength values when compared with the dual-curing resin cement.

Objective: This study evaluated the influence of low concentration acid treatment on the shear bond strength between lithium disilicate (LD) infrastructure and veneering porcelain. The surface morphology characteristic after this acid treatment was also examined. Study Design: LD reinforced ceramic cylinders (n=10) (IPS e.max Press, Ivoclar-Vivadent, Schaan, Liechtenstein) were treated (LD-treated) with a low concentration acid solution (Invex Liquid – Ivoclar-Vivadent, Schaan, Liechtenstein) or not treated with the acid solution (LD-untreated). They were veneered with a glass ceramic (IPS e.max Ceram, Ivoclar-Vivadent, Schaan, Liechtenstein). A metal ceramic group (CoCr) was tested as control. Shear bond strength (SBS) was conducted using a universal testing machine at 0.5 mm/min. Surface morphology characteristics after acid treatment were analyzed using scanning electron microscopy. Results: The acid treatment at low concentrations did not influence the SBS of the LD/veneering porcelain interface. The CoCr group showed the significant higher SBS value (35.59 ± 5.97 MPa), followed by LD-untreated group (27.76 ± 3.59 MPa) and LD-treated (27.02 ± 4.79 MPa). The fracture modes were predominantly adhesive for CoCr group and cohesive within the infrastructure for DL groups. Scanning Electron Microscopy (SEM) analysis showed no morphological differences between treated and untreated LD surfaces. Conclusions: Low concentration acid treatment did not improved SBS of veneering ceramic to LD and did not cause morphological changes on the LD surface. Key words:Lithium disilicate, glass ceramics, acid etching, shear bond strength, scanning electron microscopy.

Background: Evaluate the influence of different hybridization bonding techniques of a self-adhesive resin cement. Material and Methods: 30 human health molars were divided into six groups (n=10). The specimens received three longitudinal sections, allowing insertion of central cuts in PVC matrices. Each group received a different dentin pretreatment according to the manufacturerâ s recommendations, except the control group (G1), as follows. G2 - a 3-step total-etch adhesive system (Optibondâ ¢ FL, Kerr); G3 - a 3-step total-etch adhesive system (Adperâ ¢ Scotchbondâ ¢ Multi-Purpose, 3M ESPE); G4 - a 2-step total-etch adhesive system (Adperâ ¢ Single Bond 2, 3M ESPE); G5 - a single-step self-etching system (Bond Force, Tokuyama); and G6 - universal bonding system (Single Bond Universal, 3M ESPE). Then, cylinders made of self-adhesive resin cement with polypropylene matrix was cemented in all groups (RelyX U200, 3M ESPE). Bond strength was assessed by submitting the specimens to micro-shear test and was characterized according to the fracture pattern observed through optical microscopy. Results: The results were submitted to the Kruskal-Wallis test, which indicated a statistically significant difference between the groups (p=0.04), and Tukeyâ s multiple comparisons, which indicated a statistically significant difference between G1 and G3 (p

This study evaluated the fracture resistance of weakened roots restored with glass fiber posts, composite resin cores and complete metal crowns. Thirty maxillary canines were randomly divided into 3 groups of 10 teeth each: teeth without weakened roots (control); teeth with partially weakened roots (PWR) and teeth with and largely weakened roots (LWR). The control group was restored with glass fiber posts and a composite resin core. Teeth in the PWR and LWR groups were flared internally to standardized dimensions in order to simulate root weakness. Thereafter, the roots were partially filled with composite resin and restored in the same way as in the control group. The specimens were exposed to 250,000 cycles in a controlled chewing simulator. All intact specimens were subjected to a static load (N) in a universal testing machine at 45 degrees to the long axis of the tooth until failure. Data were analyzed by one-way ANOVA and Dunnett's test for multiple comparisons (p=0.05). There were statistically significant difference differences (p0.05) between the weakened groups. The results of this study showed that thicker root dentin walls significantly increase the fracture resistance of endodontically treated teeth. Este estudo avaliou a resistência à fratura de raízes fragilizadas restauradas com pinos de fibra de vidro, núcleos de resina composta e coroas totais metálicas. Trinta caninos superiores foram aleatoriamente divididos em 3 grupos. Dentes sem enfraquecimento (grupo controle); grupo de raízes parcialmente enfraquecidas e amplamente enfraquecidas. O grupo controle foi restaurado com pinos de fibra de vidro e núcleo em resina composta. Os dentes dos grupos de raízes parcialmente e amplamente enfraquecidas foram internamente preparadas de maneira padronizada simulando enfraquecimento. Após isto, as raízes foram parcialmente preenchidas com resina composta e restauradas como no grupo controle. Os espécimes foram expostos a 250.000 ciclos em uma máquina de ciclagem mecânica. Todos os dentes intactos foram submetidos à carga estática (N) em uma máquina de ensaio universal a 45 graus ao longo eixo do dente até a sua falha. Os resultados foram analisados através do teste ANOVA a 1 critério e teste de Dunnett para comparações múltiplas (p=0,05). A análise estatística revelou diferenças significantes (p

Proper selection of the luting agent is fundamental to avoid failure due to lack of retention in post-retained crowns. The objective of this study was to investigate the tensile bond strength and failure mode of glass fiber posts luted with different cements. Glass fiber posts were luted in 40 mandibular premolars, divided into 4 groups (n = 10): Group 1 - resin-modified glass ionomer RelyX Luting; Group 2 - resin-modified glass ionomer Fuji Plus; Group 3 - resin cement RelyX ARC; Group 4 - resin cement Enforce. Specimens were assessed by tensile strength testing and light microscopy analysis for observation of failure mode. The tensile bond strength values of each group were compared by ANOVA and Tukey test. The significance level was set at 5%. The failure modes were described as percentages. The following tensile strength values were obtained: Group 1 - 247.6 N; Group 2 - 256.7 N; Group 3 - 502.1 N; Group 4 - 477.3 N. There was no statistically significant difference between Groups 1 and 2 or between Groups 3 and 4, yet the resin cements presented significantly higher tensile bond strength values than those presented by the glass ionomer cements. Group 1 displayed 70% of cohesive failures, whereas Groups 2, 3 and 4 exhibited 70% to 80% of adhesive failures at the dentin-cement interface. We concluded that resin cements and glass ionomer cements are able to provide clinically sufficient retention of glass fiber posts, and that glass ionomer cements may be especially indicated when the application of adhesive techniques is difficult.

OBJECTIVE: This study evaluated the fracture strengths of endodontically treated teeth restored with prefabricated posts with different post lengths. MATERIAL AND METHODS: Thirty freshly extracted canines were endodontically treated. They were randomly divided into groups of 10 teeth and prepared according to 3 experimental protocols, as follows; Group 1/3 PP: teeth restored with prefabricated post and composite resin core (Z250) with post length of 5.0mm; Group 1/2 PP and Group 2/3 PP: teeth restored with prefabricated post and composite resin core (Z250) with different combinations of post length of 7.5mm and 10mm, respectively. All teeth were restored with full metal crowns. The fracture resistance (N) was measured in a universal testing machine (crosshead speed 0.5mm/min) at 45 degrees to the tooth long axis until failure. Data were analyzed by one-way analysis of variance (alpha=.05). RESULTS: The one-way analysis of variance demonstrated no significant difference among the different post lengths (P>.05) (Groups 1/3 PP = 405.4 N, 1/2 PP = 395.6 N, 2/3 PP = 393.8 N). Failures occurred mainly due to core fracture. CONCLUSIONS: The results of this study showed that an increased post length in teeth restored with prefabricated posts did not significantly increase the fracture resistance of endodontically treated teeth.

Analisou-se a percepção de mães ou responsáveis sobre a saúde-doença bucal de seus filhos, com idade de 2 a 6 anos, matriculados em uma creche filantrópica de Bauru (SP). Foram realizadas 26 entrevistas, analisadas por metodologia qualitativa. Os entrevistados foram ouvidos sobre a presença de cárie dentária em suas crianças e como compreendiam sua causalidade. Foi realizado o exame de cárie das crianças, utilizando critérios epidemiológicos para o diagnóstico. Na maioria das entrevistas (65,4%) houve concordância de respostas com a condição bucal verificada no exame das crianças. A percepção dos entrevistados sobre a presença da cárie dentária foi relacionada à aparência do dente ("furadinho") e à dor. A compreensão quanto à causalidade da doença fez referência ao cuidado dispensado às crianças pelos entrevistados, acesso ao cirurgião-dentista, ingestão de doces e à fatalidade ("Todo mundo tem cárie, pelo menos um pouquinho tem"). A maneira pela qual as pessoas percebem o processo saúde-doença influencia as práticas e os cuidados em saúde bucal. Buscar compreender estas construções e valores é essencial para se trabalhar, de forma contextualizada, a falta de informação e os conceitos que ainda persistem, como a crença que a cárie dentária é um fenômeno "natural" e não um processo patológico.

summary The aim of this study was to evaluate the fracture resistance of endodontically maxillary premolars restored with mesio-occlusal-distal (MOD) inlays made with ceramic (IPS-Empress 2) and ceromer (Targis) and luted with three different dual-cured resin cements (Enforce, Variolink II, Panavia F). Sixty maxillary premolars were randomly distributed into six groups, according to their mesio-distal and facio-lingual dimensions. The teeth were endodontically treated and MOD cavities prepared. After the restorations were cemented, the samples were thermocycled and submitted to an axial compressive load by the action of a rounded end steel cylinder contacting the incline planes of occlusal surfaces of the teeth. The mode of fracture was analysed with a microscope. The best results were found with the combinations (cement/restorative material) Enforce/Targis (107·57 kgf) and Enforce/Empress (90·21 kgf) followed by Variolink II/Targis (86·44 kgf)–Variolink II/Empress (84·07 kgf) and Panavia F/Targis (82·43 kgf)–Panavia F/Empress (76·73 kgf). Analysis of variance (P

Objectives To evaluate the influence of different resin blends concentrations and nanofibers mass ratio on flexural properties of experimental Poliacrylonitrile (PAN) nanofibers reinforced composites. Materials and methods Poliacrylonitrile (PAN) nanofibers mats were produced by electrospinning and characterized by tensile testing and scanning electron microscopy (SEM). Experimental resin-fiber composite beams were manufactured by infiltrating PAN nanofiber mats with varied concentrations of BisGMA–TEGDMA resin blends (BisGMA/TEGDMA: 30/70, 50/50 and 70/30 weight%). The mass ratio of fiber to resin varied from 0% to 8%. Beams were cured and stored in water at 37 °C. Flexural strength (FS), flexural modulus (FM) and work of fracture (WF) were evaluated by three-point bending test after 24 h storage. Results The tensile properties of the PAN nanofibers indicated an anisotropic behavior being always higher when tested in a direction perpendicular to the rotation of the collector drum. Except for WF, the other flexural properties (FS and FM) were always higher as the ratio of BisGMA to TEGDMA increased in the neat resin beams. The addition of different ratios of PAN fibers did not affect FS and FM of the composite beams as compared to neat resin beams ( p > 0.05). However, the addition of fibers significantly increased the WF of the composite beams, and this was more evident for the blends with higher TEGDMA ratios ( p Significance The inclusion of PAN nanofibers into resin blends did not negatively affect the properties of the composite and resulted in an increase in toughness that is a desirable property for a candidate material for prosthodontics application.

Made available in DSpace on 2015-08-06T16:14:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2014-10-01. Added 1 bitstream(s) on 2015-08-06T16:44:21Z : No. of bitstreams: 1 S1678-77572014000500390.pdf: 2186068 bytes, checksum: 2a282f09bce82454a2c89a135ac0f0f8 (MD5) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) OBJECTIVE: The purpose of this study was to assess the push-out bond strength of glass fiber posts to root dentin after cementation with glass ionomer (GICs) and resinmodified glass ionomer cements (RMGICs). MATERIAL AND METHODS: Fifty human maxillary canines were transversally sectioned at 15 mm from the apex. Canals were prepared with a step back technique until the application of a #55 K-file and filled. Post spaces were prepared and specimens were divided into five groups according to the cement used for post cementation: Luting & Lining Cement; Fuji II LC Improved; RelyX Luting; Ketac Cem; and Ionoseal. After cementation of the glass fiber posts, all roots were stored at 100% humidity until testing. For push-out test, 1-mm thick slices were produced. The push-out test was performed in a universal testing machine at a crosshead speed of 0.5 mm/minute and the values (MPa) were analyzed by Kolmogorov-Smirnov and Levene's tests and by two-way ANOVA and Tukey's post hoc test at a significance level of 5%. RESULTS: Fiber posts cemented using Luting & Lining Cement, Fuji II LC Improved, and Ketac Cem presented the highest bond strength to root dentin, followed by RelyX Luting. Ionoseal presented the lowest bond strength values (P>0.05). The post level did not influence the bond strength of fiber posts to root dentin (P=0.148). The major cause of failure was cohesive at the cement for all GICs and RMGICs. CONCLUSIONS: Except for Ionoseal, all cements provided satisfactory bond strength values. Dental School Dental School Department of Prosthodontics Department of Prosthodontics University of Southern Santa Catarina Federal University of Rio Grande do Sul Department of Conservative Dentistry Univ. Estadual Paulista School of Dentistry Department of Endodontics University of São Paulo Bauru School of Dentistry Department of Pediatric Dentistry, Orthodontics and Community Health University of São Paulo Bauru School of Dentistry Department of Prosthodontics

Statement of problem The mechanical stability of the implant-abutment connection is of fundamental importance for successful implant-supported restorations. Therefore, understanding removal torque values is essential. Purpose The purpose of this study was to evaluate the reverse torque values of indexed and nonindexed abutments of the Morse Taper system. Material and methods Twelve Morse taper implants with their respective abutments were divided into 2 groups (n=6): group NI, nonindexed abutments; and group IN, indexed abutments. Each abutment received a sequence of 2 consecutive torques for insertion (15 Ncm) at an interval of 10 minutes, and 1 reverse torque, all measured with a digital torque wrench. The Student t test with a 5% significance level was used to evaluate the data. Results Statistical analysis showed no significant difference in reverse torque values between nonindexed and indexed abutments ( P =.57). When comparing insertion torque and reverse torque values between the groups, group NI presented a mean torque loosening percentage of 8% ( P =.013), whereas group IN presented a loosening of 15.33% ( P Conclusion The use of indexed abutments for the Morse taper system presented similar biomechanical stability when compared with nonindexed abutments, both with a significant reduction in reverse torque values.

A conservative treatment is presented for a patient with complex severe esthetic problems related to the presence of anomalous teeth. The patient showed a rare occurrence of macrodontia of the maxillary right lateral incisor and microdontia of the maxillary left lateral incisor. The treatment plan was conservative to avoid tooth extraction, periodontal tissue trauma, and the risk of an unpredictable esthetic outcome. A multidisciplinary treatment involving orthodontic extrusion, endodontic therapy, periodontal therapy, and minimally invasive restorations was performed. A successful outcome was observed after a 2-year follow-up.

Statement of the problem The connection between abutments and implants is fundamental to successful prosthetic rehabilitation, and the loosening or fracture of the parts are undesirable outcomes. Purpose The purpose of this study was to measure the reverse torque values of 2 different types of Morse taper implants. Material and methods Ten Morse taper implants were used, with their respective abutments. They were divided into 2 groups (n = 5): Group DH, implant interface with a double hexagon and Group OI, octagonal implant interface. Each abutment received 2 consecutive insertion torques (32 Ncm) at a 10-minute interval and 1 reverse torque after 5 minutes. The data were analyzed with the Student t test (α= .05). Results The Student t test demonstrated no significant differences between the values of the insertion and removal torques of the 2 groups (Group DH, P = .22 and Group OI, P = .42) or the removal torque values of the groups ( P = .12). Conclusion The results suggest that the strength required to loosen the abutment screws as measured by reverse torque is similar for both a double hexagon interface (DH) and an octagonal interface (OI).

A confecção de infra-estruturas metálicas em reabilitações orais, envolvem processos criteriosos principalmente no que concerne ao processo de fundição e soldagem das mesmas. O objetivo deste trabalho foi avaliar a resistência à tração de peças fundidas em monobloco com três diferentes métodos de soldagem: solda convencional (maçarico), solda a laser e solda TIG (tungstênio Inerte Gás). Oitenta padrões de plástico pré-fabricados (vinte para cada grupo) foram fundidos em liga de Ni-Cr, sendo o grupo controle (monobloco) unido previamente à fundição. Após, os corpos-de-prova do grupo teste foram divididos aleatoriamente para posterior soldagem e teste de resistência, realizado em uma máquina de ensaios mecânicos (Kratos). Os resultados médios (MPa) foram: monobloco 784,08, solda laser 588,42, solda convencional 366,80 e solda TIG 319,78. Os dados foram submetidos á analise estatística ANOVA e teste de Tukey (p,0,05), sendo que o grupo controle (monobloco) apresentou valores de resistência estatisticamente superior a todos os do grupo teste. Entre as peças soldadas, a solda laser apresentou valores de resistência estatisticamente superior em relação aos grupos (convencional e TIG), os quais não diferiram estatisticamente entre si. Concluí-se que apesar de ter havido diferenças estatísticas entre os grupos, os três métodos de soldagem podem ser indicadas pelos resultados altamente satisfatórios. The development of metallic prosthetic framework in oral rehabilitation, involves critical processes specially related to casting and welding. The objective of this work was to evaluate the tensile strength of cast plates (monobloc) with three different welding methods: conventional welding (torch), laser welding and TIG welding (tungsten inert gas). Eighty pre fabricated plastic patterns (twenty for each group), were welded in Ni-Cr alloy, being the control group (monobloc) jointed previously to welding. The specimens of the test group were randomly divided for posterior welding and tensile strength test, which were performed in an universal testing machine (Kratos). The mean values (Mpa) were: monobloc (control) - 785.08, laser welding - 588.42, conventional welding - 366.80 and TIG 319.78. Data were analyzed by One-way ANOVA and Tukey test (p.0.05). The control group (monobloc) presented tensile strength values statistically superior compared to all test groups. Between the welded patterns, the laser welding presented tensile strength values statistically superior compared to the other welding groups (conventional and TIG), which did not show any statistically difference between them. Therefore, it can be concluded that despite of the statistical difference between the groups, the three welding methods can be indicated by the highly satisfactory results.

Purpose: The purpose of this study was to evaluate the number of bubbles of hydrogen liberation from different polyvinylsiloxane impression materials. Material and Methods: A metallic stainless steel jig containing six receptacles, like trays, was constructed to accommodate the impression materials. The molds were poured immediately, and at 1 hour, 12 hours and 24 hours in order to evaluate the number of bubbles present in each sample. Each sample was made of improved stone (type IV), totaling 48 samples for each polyvinylsiloxane impression material. After setting, the surface of each sample was inspected under a light microscope at 40x magnification and the number of bubbles was recorded. Results were submitted to statistical analysis by ANOVA and Tukey Test (p=.05). Results: ANOVA test showed statistically significant differences among the polyvinylsiloxane impression materials, as determined by the number of bubbles (p

Resin cements are widely used to cement intraradicular posts, but bond strength is significantly influenced by the technique and material used for cementation.The purpose of this study was to evaluate the bond strength of 3 self-adhesive cements used to cement intraradicular glass fiber posts. The cements all required different application and handling techniques.Forty-five human maxillary canines were selected and randomly divided into 3 groups n= 15 by drawing lots: Group BIS - Biscem, Group BRE - Breeze, and Group MAX - Maxcem. Each group was divided into 3 subgroups according to application and handling techniques: Sub-group A - Automix/Point tip applicator, Sub-group L - Handmix/Lentulo, and Sub-group C - Handmix/Centrix. Cementation of the posts was performed according to the manufacturers' instructions. The push-out test was performed with a crosshead speed of 0.5 mm/min, and bond strength was expressed in megapascals. The results were evaluated by 2-way ANOVA and the all pairwise multiple comparison procedures (Tukey test) (α=.05).Breeze cement showed the highest average for the subgroups A, L, and C when compared to the Biscem cement and Maxcem Elite (P.05). Statistically significant differences among the subgroups were only observed for Biscem.This study shows that application and handling techniques may influence the bond strength of different self-adhesive cements when used for intraradicular post cementation.

ObjectivesThe purpose of this study was to evaluate the influence of thermal and mechanical cycling and veneering technique on the shear bond strength of Y-TZP (yttrium oxide partially stabilized tetragonal zirconia polycrystal) core–veneer interfaces.Materials and methodsCylindrical Y-TZP specimens were veneered either by layering (n=20) or by pressing technique (n=20). A metal ceramic group (CoCr) was used as control (n=20). Ten specimens for each group were thermal and mechanical cycled and then all samples were subjected to shear bond strength in a universal testing machine with a 0.5mm/min crosshead speed. Mean shear bond strength (MPa) was analysed with a 2-way analysis of variance and Tukey's test (p