Tomographic late evaluation of xenogeneic bone grafts in sockets of impacted third molars

Abstract It is necessary to preserve height and thickness of the alveolar bone to facilitate rehabilitation with osteointegratable implants or simply to maintain bone integrity after extraction. Biomaterials associated with resorbable or non-resorbable membranes, when placed in the region of the socket, may contribute to avoid this unwanted reabsorption. Objective The objective of this study was to evaluate the distance of the crest of alveolar ridge to the cementoenamel junction (CEJ) of the lower second molars and the bone density of the third molar socket filled with Gen-Tech®, 5 years after an exodontia using cone beam computed tomography (CBCT) to visualize the central region of the sockets, without overlapping of the buccal and lingual cortical bones. Material and Methods A total of 12 individuals from an initial group of 39 patients submitted to extraction of the unruptured lower third molars and grafting of an association of inorganic bovine bone matrix, organic bovine bone matrix, collagen and bone morphogenetic proteins (BMP) (Gen-Tech®) on one side and the contralateral sockets filled only by clot, returned to control after 5 years, and were submitted to CBCT. The distance from the crest of alveolar bone to the CEJ and the bone density (BD) were measured using the i-CAT Vision Software. Results The results showed that the distance from the crest of alveolar bone to the CEJ in the control group was similar to that observed before the exodontia; in the experimental group, this distance was smaller. Considering the BD measurement, a significantly higher density was observed in the experimental group (p<0.05). Conclusion Part of the biomaterial was not absorbed and allowed the stability of the evaluated parameters after 5 years, being able to be used as a bone substitute in the socket.

Low-concentrated nonvital bleaching effect on bond strength of composite resin restorations / Efeito de clareadores não-vitais pouco concentrados sobre a força de cisalhamento de restaurações de resina composta

Objective: To investigate if short-term dentin bleaching with low-concentrated substances affects the bond strength of immediate resin composite restorations. Material and Methods: The buccal surfaces of fifty molar crowns were ground for dentin exposure and randomly assigned into 5 groups (n=10), according to the following treatments: sodium perborate + water; sodium perborate + 6% hydrogen peroxide; 6% hydrogen peroxide; 35% hydrogen peroxide (positive control), or no bleaching agent (negative control). The specimens were immediately restored with resin composite. Seven days after treatments, the shear bond test was performed in a universal test machine at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukey’s HSD test (α = 0.05). Results: The shear bond strength mean values for the negative control group were higher than all experimental and positive control groups (p < 0.000), whose differences were not statistically significant (p > 0.05). Conclusion: Short-term dentin bleaching with sodium perborate+water, 6% hydrogen peroxide, or sodium perborate mixed with 6% hydrogen peroxide reduced the shear bond strength of immediate resin composite restorations.

Objetivo: Investigar se o clareamento rápido da dentina com substâncias de baixa concentração afeta a resistência de união ao cisalhamento de restaurações imediatas de resina composta. Material e Métodos: As superfícies vestibulares de cinquenta molares foram desgastadas para exposição da dentina e então aleatoriamente alocadas em 5 grupos (n = 10), de acordo com as substâncias clareadoras: perborato de sódio + água; perborato de sódio + peróxido de hidrogênio a 6%; peróxido de hidrogênio a 6%; peróxido de hidrogênio a 35% (controle positivo); ou nenhum agente clareador (controle negativo). Os espécimes foram imediatamente restaurados com resina composta. Sete dias após os tratamentos, testes de resistência ao cisalhamento foram realizados em uma máquina de ensaios universal a uma velocidade de cruzeta de 0,5 mm/min. Os dados foram analisados com os testes ANOVA e Tukey HSD (α = 0,05). Resultados: Os valores de resistência ao cisalhamento do grupo controle negativo foram maiores do que os dos grupos experimentais e controle positivo (p < 0,001), cujas diferenças não foram estatisticamente significativa (p > 0,05). Conclusão: Clareamentos dentinários rápidos com perborato de sódio, peróxido de hidrogênio 6% ou perborato de sódio misturado com peróxido de hidrogênio 6% reduziram a força de resistência ao cisalhamento de restaurações imediatas de resina composta.

Influence of root canal sealer on the radiographic appearance of filling voids in maxillary single-rooted teeth

OBJECTIVE: This study compared the influence of three epoxy resin-based sealers with distinct radiopacities on the observers' ability to detect root canal filling voids during radiographic analysis. MATERIAL AND METHODS: The root canals of 48 extracted maxillary canines were prepared and divided into three groups. Each group was laterally condensed with one sealer (AH Plus®, Acroseal® or a non-radiopaque sealer), and a longitudinal void was simulated in half of the specimens from each group (n=8). Buccolingual radiographs were obtained and randomly interpreted for voids by a radiologist and an endodontist in a blinded fashion. Teeth were cut and inspected under a microscope to confirm the position of void. Differences in sensitivity and specificity between groups and examiners were compared using the Fisher's Exact and McNemar tests, respectively (α=0.05). RESULTS: Significantly lower sensitivity levels (p<0.05) were observed in the coronal portion of fillings performed with both radiopaque sealers. Specificity values for Acroseal® were significantly higher (p<0.05) in the coronal and apical portions of fillings. CONCLUSIONS: The type of root canal sealer can affect the observers' ability to detect root canal filling voids during radiographic analysis of upper single-rooted teeth.

Digital radiopacity measurement of different resin- and zinc oxide-based root canal sealers / Mensuração digital da radiopacidade de diferentes cimentos obturadores resinosos e de base zinco-enólica

Purpose: To evaluate the radiopacity produced by seven commercially available (AH Plus, Epiphany, Sealapex, Acroseal, Sealer 26, Endomethasone and Endofill) and one experimental (MBP) root canal sealers. Methods: Sealer radiopacity testing was performed according to ANSI/ADA Specification No. 57. Specimens were radiographed with an aluminum stepwedge, and the resulting images were digitalized. Radiographic densities expressed in Aluminum mm (mm Al) were compared using an ANOVA and Tukey test (alpha=0.05). Results: AH Plus (10 mm Al) and Epiphany (9.0 mm Al) were the most radiopaque root canal sealers, followed by Sealapex (8 mm Al), Endofill (7 mm Al), Endomethasone (7 mm Al), MBP (7 mm Al) and Sealer 26 (6 mm Al). Acroseal (5 mm Al) showed the smallest radiopacity among the tested sealers (P<0.05). Conclusion: The radiopacities of the tested sealers were above the minimum level recommended by ANSI/ADA Specification No. 57.

Objetivo: Avaliar a radiopacidade produzida por sete cimentos comercialmente disponíveis (AH Plus, Epiphany, Sealapex, Acroseal, Sealer 26, Endomethasone and Endofill) e um em estágio experimental (MBP). Metodologia: Depois de homogeneizados os materiais, o teste de radiopacidade foi executado conforme a especificação no 57 da ANSI/ADA. Radiografou-se os espécimes junto a uma escala de Alumínio e as imagens resultantes foram digitalizadas. As densidades radiográficas expressas em milímetros de Alumínio (mm Al) foram comparadas por meio da análise de variância e teste de Tukey (alfa=0.05). Resultados: Os cimentos AH Plus (10 mm Al) e Epiphany (9 mm Al) apresentaram as maiores radiopacidades seguidos pelo Sealapex (8 mm Al), Endofill (7 mm Al), Endométhasone (7 mm Al), MBP (7 mm Al) e Sealer 26 (6 mm Al). Acroseal (5 mm Al) mostrou a menor radiopacidade entre os cimentos testados (P<0.05). Conclusão: Concluiu-se que as diferentes radiopacidades dos cimentos testados estão acima do nível mínimo recomendado pela especificação nº 57 da ANSI/ADA.

Radiopacidade do cimento Portland adicionado de agentes radiopacificadores em diferentes proporções / Radiopacity of Portland cement added of radiopacifying agents in different proportions

Introdução - Este estudo avaliou o potencial radiopacificador de algumas substâncias adicionadas ao cimento Portland em diferentes concentrações. Material e Métodos - Oxido de bismuto, subnitrato de bismuto ou sulfato de bário foram incorporados ao cimento Portland nas seguintes proporções: 15, 20, 25 e 30% de peso. O cimento Portland puro e guta-percha obturadora serviram como controles. Depois de manipulados os compostos, o teste de radiopacidade foi conduzido conforme a especificação ANSI/ADA nº 57 (2000) (n=8). Radiografou-se os espécimes junto a uma escala de alumínio e em seguida as imagens resultantes foram digitalizadas para que as densidades radiográficas dos cimentos pudessem ser comparadas por meio da análise de variância (ANOVA) e do teste de Tukey. Resultados - O cimento Portland puro revelou radiopacidade significativamente inferior à das demais misturas testadas. Na proporção de 15% a densidade radiográfica resultante dos sais de bismuto foi superior à do sulfato de bário, mas inferior à da guta-percha. Na proporção de 20% somente o óxido de bismuto produziu radiopacidade similar à da guta-percha, resultado alcançado pelo subnitrato de bismuto somente nas proporções de 25 e 30%, mas nunca alcançado pelas combinações cimento Portlando/sulfato de bário (p<0,05). Conclusões - Todas as substâncias, nas proporções testadas, podem ser potencialmente adicionadas ao cimento Portland como agentes radiopacificadores.