No abstract

A reabilitação oral com prótese total removível (PTR) visa à devolução de estética e função aos pacientes desdentados, apesar de ser considerada facilitadora de várias patologias bucais. Assim, o objetivo deste estudo foi conhecer os hábitos de higiene bucal dos usuários de PTR, o estado de conservação associado à presença de lesões bucais e o recebimento de orientação profissional. Sessenta usuários de PTR foram entrevistados e suas próteses avaliadas quanto à higiene, conservação e saúde bucal. Observou-se que 96,7% dos pesquisados não receberam orientação profissional, o método mecânico foi o mais utilizado para higienização e realizado três vezes ao dia (36,7%). A higiene das PTR apresentou-se moderada e as características funcionais estavam insatisfatórias. A queilite angular não teve significância estatística, quando associada ao nível de higiene. A ausência de retenção e estabilidade estática associou com as lesões no maxilar inferior (p=0,02). As características deficientes das PTR representam uma tendência para a ocorrência de lesões bucais e os participantes, apesar da higiene frequente, não conheciam a forma correta de higienização e não receberam orientação que a PTR poderia causar lesões bucais.

No abstract

This study aimed to compare the effect of four irrigation solutions for post space cleaning on the bond strength between glass fiber post and root dentine. Forty bovine roots were root-filled and randomly divided into four groups (n=10), according to the irrigation solution: CG (Control Group): saline solution; SH (Sodium Hypochlorite Group); CLX (Chlorhexidine group) and EDTA (ethylenediaminetetraacetic acid group). Specimens were submitted to mechanical aging and push-out test. Statistical analysis (ANOVA two-way and Tukey test; p<0.05) was performed. A stereomicroscope was used for failure mode classification. EDTA showed higher bond strength values, differing statistically from SH and CG (p<0.05). Adhesive failure between dentin and resinous cement was predominant, followed by mixed failures. SEM images showed pronounced smear layer removal in the EDTA group. 17 % EDTA was better than other solutions for cleaning of post space when using glass fiber posts.

O conhecimento do comportamento mecânico do sistema de implante corresponde a um importante parâmetro no prognóstico de uma reabilitação protética. Objetivo: avaliar a influência do formato de tecido ósseo na distribuição de tensões no implante do tipo cone morse e tecido ósseo por meio do método dos elementos finitos tridimensionais. Materiais e método: foram utilizados três tipos de formatos de modelos para tecidos ósseos: a) paralelepípedo; b) tronco elíptico; c) gerado a partir dos dados de uma tomografia. Nos modelos tridimensionais, foram instalados implantes que receberam aplicação de duas cargas de 100 N no sentido craniocaudal: 1) na direção vertical ao longo do eixo axial e 2) na direção oblíqua a 45° do eixo axial de vestibular para lingual. Resultados: as tensões de von Mises máximas (MPa) nos modelos do implante cone morse (CM) e do tecido ósseo do tipo paralelepípedo foram de 14.30 no carregamento vertical e de 60.78 no carregamento oblíquo; no modelo de tecido ósseo elíptico, foram de 14.69 no carregamento vertical e de 71.66 no carregamento oblíquo; no modelo de tecido ósseo com a configuração originada da tomografia, foram de 15.04 no carregamento vertical e de 79.15 no carregamento oblíquo. Conclusão: o formato dos modelos de tecido ósseo influenciou no comportamento e na distribuição das tensões, sendo que o modelo gerado pelos dados da tomografia apresentou os maiores valores de tensões.

<p><strong>Objetive</strong>: This research aimed to verify the performance of thermally activated acrylic resin (TAAR) combined with a mix of glass and aramid fibers and/or composite resin of indirect use by a tree point bending test. <strong>Material and Methods:</strong> Ten samples, with 65 x 10 x 2.5 mm, were prepared for each group (n = 10): CO, control of only TAAR; CR, in which an 60 mm indirect composite resin was polymerized together with the acrylic resin during the thermo-polymerization cycle; SS, in which ceramic glass mixed with aramid fibers cut 60 mm in length were incorporated into the samples; and SC, in which the same fibers were incorporated with addiction of the indirect composite resin. A three-point flexural strength test was performed with a universal testing machine with a load of 50KgF at a speed of 5 mm/min in the center of the samples supported by a suitable device. The reinforced face was placed to the tensile side. The statistical one-way ANOVA and Tukey tests were made with a significance level of 95%. <strong>Results</strong>: The mean value for the CO was 60,27 ± 24,18 MPa, for CR it was 38,39±12,75 MPa, for SS it was 79,97±12,75 Mpa and for CS it was 32,40±9,05 MPa. <strong>Conclusion</strong>: The use of glass and aramid fibers at the base of a TAAR increased the three-point flexural strength, however when indirect composite resin was incorporated, a significant drop of this mechanical property was observed.</p><p> </p><p><strong>Keywords</strong></p><p>Acrylic resin; Complete denture; Composite resin.</p>

The aim of this study was compare the effect of two in vitro ageing protocols to intraoral aging on the flexural strength of a lithium disilicate (LD) ceramic bars with clamped ends. After polishing and crystallization, the both ends of the bars were cemented to a metallic device and subjected to mechanical cycling, thermomechanical cycling, or intraoral ageing. Ten volunteers used an intraoral device - similar to an occlusal splint with a balanced contact condition on the occlusal surface of the ceramic bar - during 8 h night time / 30 days. Both in vitro and intraoral ageing decreased the flexural residual strength of LD, with the lowest values obtained after intraoral ageing. Thus, the in vitro ageing protocols tested in this study revealed to be less deleterious than intraoral ageing of LD.

The aim of this study was to determine if multiple processing (heat-pressing) of a dental ceramic influences flexural strength, hardness, and microstructure. Ninety bar-shaped specimens (15 mm × 4 mm × 2 mm) of a pressed ceramic (Vita PM9) were fabricated and randomly divided into 6 groups (n = 15) according to the factors "number of pressings" (C1, C2, and C3, fired 1, 2, and 3 times, respectively) and "mechanical cycling" (M). Half of the specimens were mechanically cycled (10 6 cycles, 45 N, 3.4 Hz, in water) and all specimens were tested for 3-point bending (0.5 mm/min, load 1000 kgf) and Vickers hardness (19.6 N for 20 s). X-ray diffraction was used to characterize the phases and scanning electron microscopy to characterize the microstructure. The flexural strength data was statistically analyzed with Weibull analysis, ANOVA, and Tukey test. Hardness data was evaluated by 2-way ANOVA and Fisher test. All tests were performed with a significance level of 0.05. Two-way ANOVA revealed that neither "number of pressings" (p=0.085) or "mechanical cycling" (0.055) significantly affected flexural strength. But Weibull analysis showed significant difference for Weibull moduli and characteristic strength between groups. For hardness, a statistical difference was seen for the interaction "Number of pressings * Mechanical cycling", (p = 0.016). Hardness decreased in the following order: C1 (775±17.2), CM3 (751±101), CM2 (735±45), C3 (701±82), CM1 (671±82), and C2 (663±92). Fewer defects were observed with an increased number of firings. Therefore, the possibility of recycling PM9 ceramic does not interfere in the evaluated mechanical properties and improves microstructure.