Avaliação da interface entre o componente protético reto e a conexão interna tipo Cone Morse do implante dentário por meio da microscopia eletrônica de varredura / Evaluation of the interface between the straight prosthetic component and the Morse Cone-type internal connection of the dental implant in cross section by scanning electron microscopy

Resumo Introdução A interface implante-pilar protético e a formação dos seus microgaps são aspectos relevantes na transferência das cargas e na resposta biológica, estando ligadas ao sucesso da reabilitação. Objetivo Avaliar microgaps na interface entre a conexão interna do implante do tipo Cone Morse e a superfície do componente protético por meio da microscopia eletrônica de varredura (MEV). Material e método Foram utilizados 20 implantes dentários de tamanho 3,75 × 11,0mm do tipo Cone Morse com seus respectivos pilares protéticos da Singular® (Singular Implants, RN, Brasil). Os munhões retos foram acoplados aos implantes com torque de 32N/cm2 e o conjunto resultante foi emergido em base de Resina Epóxi ES260, para permitir secção longitudinal da amostra. As amostras foram analisadas e os microgaps mensurados no MEV (JEOL JCM-5700, MA, USA), e posteriormente os dados foram analisados. Resultado A média e o desvio padrão dos maiores microgaps foram observados na parte apical do implante nos lados direito e esquerdo, sendo 1,44±2,68 e 1,16±1,49 μm, respectivamente. Os menores microgaps foram na parte superior do implante nos lados direito e esquerdo, sendo 0,60±0,73 e 0,66±0,67 μm, respectivamente. Contudo, no teste de Kruskal-Wallis, não houve diferença estatisticamente significativa entre as regiões dos implantes, tanto para o lado esquerdo (p=0,692) como para o direito (p=0,865). No teste de Mann-Whitney, não houve diferenças estatisticamente significativas entre os lados para as diferentes regiões dos implantes. Conclusão Mesmo com a presença de microgaps na interface implante-pilar protético, estes apresentam tamanho inferior ao que causaria problemas biológicos e mecânicos. As amostras analisadas quanto à sua compatibilidade de encaixe foram satisfatórias.

Abstract Introduction The implant-prosthetic abutment interface and the formation of its microgaps are relevant aspects in load transfer and biological response and are linked to the success of the rehabilitation. Objective To evaluate microgaps at the internal connection interface of the Cone Morse implant and the prosthetic component surface by means of scanning electron microscopy (SEM). Material and method Twenty 3.75 x 11.0 mm Cone Morse dental implants with their respective Singular® prosthetic abutments were used (Singular Implants, RN, Brazil). The straight trunnions were attached to the implants with a 32N/cm2 torque and the ES260 Epoxy Resin-based set emerged to allow longitudinal sectioning of the sample. The samples were analyzed and the microgaps measured in SEM (JEOL JCM-5700, MA, USA), and later the data were analyzed. Result The mean and standard deviation of the largest microgaps were observed in the apical part of the right and left side 1.44±2.68 and 1.16±1.49 μm, respectively. The smallest microgaps were on the upper implant right and left sides 0.60±0.73 and 0.66±0.67 μm, respectively. However, in the Kruskal-Wallis test there was no statistically significant difference between the implant regions, both for the left side (p=0.692) and right side (p=0.865). The Mann-Whitney test, there were no statistically significant differences between the sides for the different regions of the implants. Conclusion Even with the presence of microgaps in the implant-post interface, it presents a smaller size than the one presenting biological and mechanical problems. The samples analyzed for their fitting compatibility were satisfactory.

Preemptive use of piroxicam on tooth sensitivity caused by in-office bleaching: a randomized clinical trial

Abstract This clinical trial evaluated the effect of preemptive use of the non-steroidal anti-inflammatory drug piroxicam in a single dose 30 min prior to in-office bleaching on the prevention of tooth sensitivity (TS) reported by patients. Fifty patients were submitted to two sessions of in-office tooth bleaching with 35% hydrogen peroxide used for 2 sessions, each consisting of a single 45-min application, with an interval of 7 days between session. Thirty minutes prior to the procedure, the patient randomly received a single dose of piroxicam (200 mg) or placebo in a double-blind, randomized, crossover design. The TS was evaluated using verbal rate (VRS) and visual analog (VAS) scales during the bleaching procedure and at 24 h after each session. The color changes were assessed by the Vita Bleachedguide scale 1 week after each bleaching session. Risk of TS was calculated from the VRS and analyzed by the McNemar test, while the level of TS was analyzed by the Mann-Whitney test. For the VAS, t-tests were used to compare data from the treatments at each assessment time. Data regarding color changes were subjected to Wilcoxon and Mann-Whitney tests (α=0.05). The preemptive administration of piroxicam did not affect the risk and level of TS compared to placebo, irrespective of the assessment time. The treatment sequence did not affect bleaching effectiveness. In conclusion, the administration of a single dose of piroxicam prior to in-office tooth bleaching was unable to significantly reduce the risk and level of TS.

Resumo Este ensaio clínico avaliou o efeito do uso preemptivo do anti-inflamatório não-esteroidal piroxicam em dose única 30 minutos antes do clareamento de consultório na prevenção de sensibilidade dentária (SD) relatada pelos pacientes. Cinquenta pacientes foram submetidos a duas sessões de clareamento dental em consultório com peróxido de hidrogênio a 35% por 2 sessões, consistindo de aplicação única de 45 minutos, com um intervalo de 7 dias entres as sessões. Trinta minutos antes do procedimento, o paciente recebia aleatoriamente dose única de piroxicam (200 mg) ou do placebo em um desenho duplo-cego, randomizado e cruzado. A SD foi avaliada usando a escalas de gradação verbal (EGV) e visual analógica (EVA) durante o procedimento clareador e 24h após o procedimento. As mudanças de cor foram avaliadas usando a escala Vita Bleachedguide uma semana após cada sessão de clareamento. O risco de SD foi calculado a partir de EGV a analisado pelo teste de McNemar, enquanto o nível de SD foi analisada pelo teste de Mann-Whitney. Para EVA, testes T foram usados para comparar dados dos tratamentos em cada tempo de avaliação. Dados de mudança de cor foram submetidos aos testes de Wilcoxon e Mann-Whitney (α=0.05). A administração preemptiva de piroxicam não afetou o risco e nível de SD quando comparado ao placebo, independentemente do tempo de avaliação. A sequencia de tratamento não afetou a efetividade do clareamento. Como conclusão, a administração de dose única de piroxicam previamente ao clareamento dental de consultório não foi efetiva em reduzir significantemente o risco e nível de SD.

High-concentration carbamide peroxide can reduce the sensitivity caused by in-office tooth bleaching: a single-blinded randomized controlled trial

Abstract Objectives A single-blinded, randomized, parallel clinical trial evaluated the use of 37% carbamide peroxide (CP) on bleaching effectiveness and tooth sensitivity reported by patients undergoing in-office tooth bleaching, in comparison with the results of using 35% hydrogen peroxide. Material and Methods Forty patients were allocated to receive two sessions of in-office tooth bleaching using either 35% hydrogen peroxide (HP) or 37% CP. Each patient's sensitivity level was evaluated during and up to 24 h after bleaching. The effectiveness of the bleaching procedures was evaluated with a spectrophotometer one week after each session and 30 days after the last session. The impact of tooth bleaching on the patients' perceptions regarding smile changes, in addition to the bleaching procedures and their results, were also recorded. Absolute and relative sensitivity risks were calculated. Data on sensitivity level were analyzed using the Mann-Whitney or T-test, and data from the color evaluation were subjected to 2-way repeated measures ANOVA. Results The use of CP reduced the risk and level of tooth sensitivity to values close to zero, whereas the difference between the bleaching agents disappeared after 24 h. An increased bleaching effect was observed for HP, mainly due to an improved reduction of redness and yellowness. Participants perceived improved tooth bleaching for HP and reduced sensitivity for CP, but no differences regarding the comfort of the techniques were noted. Conclusions In our study, 37% CP resulted in reduced tooth sensitivity but decreased the tooth bleaching effectiveness. However, both bleaching agents resulted in high levels of patient satisfaction.