Influence of customization and light-curing device on the bond strength of glass fiber posts - in vitro study / Influência da reanatomização e do aparelho fotopolimerizador na resistência de união de pinos de fibra de vidro - estudo in vitro

Introduction: Endodontically treated teeth are usually affected by extensive structure loss requiring the use of intraradicular posts to provide retention and restoration. Objective: An in vitro assessment was performed on the bonding of glass fiber posts to the root dentin. Material and method: Ninety (n = 10) single bovine roots were used in a 3 x 3 x 3 factorial study with subdivided plots: post customization varying the presence and type of resin (without customization, conventional resin, and Bulk Fill resin), light-curing device (Valo, Radii-Cal, Rainbow), and root third (cervical, middle, and apical). Result: For the customization factor, Tukey's test (5%) showed the superiority of the Bulk Fill (8.16 MPa) and Z350 (7.40 MPa) groups compared to the control group (4.92 MPa), without differing from each other. All light-curing devices differed, showing the superiority of Valo (9.36 MPa), Radii (6.96 MPa) as an intermediate, and the inferiority of Rainbow (4.17 MPa). The cervical root third (7.81 MPa) was superior, the apical third was inferior (5.80 MPa), and the middle third (6.88 MPa) was an intermediate without differing from the others. Conclusion: The customization of glass fiber posts increases the bond strength to the root dentin, regardless of the resin used. There was a compromise in the apical third and when using light-curing devices with lower light intensity.

Introdução: Dentes com extensa perda de estrutura podem comprometer a retenção das restaurações ao remanescente dental, onde pinos intraradiculares são indicados. Objetivo: Avaliou-se in vitro a união de pinos de fibra de vidro à dentina radicular em função de diferentes modos de reanatomização, fotopolimerizadores e regionalização radicular. Material e método: Noventa (n=10) raízes bovinas uniradiculares foram usadas num estudo fatorial 3 x 3 x 3 com parcelas subdivididas: Reanatomização do pino, variando a presença e tipo de resina (Sem reanatomização, Resina Convencional e Resina Bulkfill); Fotopolimerizador (Valo, Radii-cal, Rainbow); e Terço radicular (cervical, médio e apical). Resultado: O teste de Tukey (5%) evidenciou para o Fator Reanatomização superioridade dos grupos BulkFill (8.16MPa) e Z350 (7.40MPa) ao grupo Controle (4.92MPa), sem diferirem entre si. Todos os fotopolimerizadores diferiram entre si, com superioridade de Valo (9.36MPa), Radii (6.96MPa) intermediário, e inferioridade de Raiwbow (4.17MPa). O terço radicular cervical (7.81MPa) foi superior e o apical inferior (5.80MPa), com o terço médio (6.88MPa) intermediário e sem diferir dos demais. Conclusão: Conclui-se que a reanatomização de pinos de fibra de vidro aumenta a resistência de união à dentina radicular, independentemente da resina utilizada, havendo prejuízo no terço apical e quando são empregados fotopolimerizadores com menor intensidade luminosa.

Estudio de la relación de los terceros molares superiores retenidos y el seno maxilar en radiografías panorámicas y tomografía (CBCT) / Study of the relationship of retained upper third molars and maxillary sinus in panoramic radiographs and tomography (CBCT)

Objetivo: Evaluar la eficacia de la radiografía panorámica para establecer la relación de los terceros molares superiores y la cortical inferior del seno maxilar, en comparación con la tomografía computarizada de haz cónico (CBCT). Material y métodos: El trabajo incluyó 72 pacientes, se estudiaron 34 terceros molares superiores retenidos izquierdos y 38 derechos. Se realizaron mediciones con el programa para establecer la distancia entre la cortical inferior del seno maxilar y el ápice del tercer molar superior a partir de la imagen de la radiografía panorámica en lo que se estableció como parámetros: «a distancia, en contacto y dentro del piso de seno maxilar¼. Luego, con los cortes oblicuos o paraaxiales de la tomografía computarizada (CBCT) se observó la verdadera ubicación en el plano bucopalatino. Resultados: Del total de los terceros molares superiores 34 fueron izquierdas (47.22%) y 38 derechas (52.78%). En la Rx. Panorámica, 18 casos (25%) se encontraron a distancia al seno maxilar, 12 en contacto (16.7%) y 42 por dentro (58.3%) del seno maxilar. En la tomografía se observaron 20 casos (27.8%) a distancia del conducto, 16 (22.2%) en contacto y 36 (50%) por dentro del seno maxilar. Se observaron diferencias estadísticamente significativas (p < 0.05) entre la Rx. panorámica y la tomografía (CBCT) de los terceros molares que se hallan por dentro del seno maxilar. Conclusión: A partir de los resultados obtenidos, podemos establecer que la radiografía panorámica no permite conocer la verdadera relación entre la cortical inferior del seno maxilar y los terceros molares superiores (AU)

Objective: To evaluate the effectiveness of panoramic radiography to establish the relationship of the upper third molars and the inferior cortical of the maxillary sinus, in comparison with the Cone Beam Computed Tomography (CBCT). Material and methods: The work included 72 patients, 34 upper left maxillary molars and 38 rights were studied. Measurements were made with the program to establish the distance between the lower cortex of the maxillary sinus and the apex of the upper third molar from the image of the panoramic radiograph in what was established as parameters: «at a distance, in contact and inside the floor of maxillary sinus¼. Then with the oblique or paraaxial slices of the computed tomography (CBCT) the true location in the bucco-palatal plane was observed. Results: Of the total upper third molars, 34 were left (47.22%) and 38 right (52.78%). In the panoramic X-ray 18 cases (25%) were found at distance to the maxillary sinus, 12 in contact (16.7%) and 42 inside (58.3%) of the maxillary sinus. The tomography showed 20 cases (27.8%) at a distance from the canal, 16 (22.2%) in contact and 36 (50%) inside the maxillary sinus. Statistically significant differences were observed (p < 0.05) between the Rx. panoramic and tomography (CBCT) of the third molars that are inside the maxillary sinus. Conclusion: From the results obtained, we can establish that the panoramic radiograph does not allow knowing the true relationship between the inferior cortical of the maxillary sinus and the upper third molars (AU)

Grinding of composite cores using diamond burs with different grit sizes: the effects on the retentive strength of zirconia crowns

Aim: To evaluate the retention of Y-TZP crowns cemented in aged composite cores ground with burs of different grit sizes. Methods: Sixty composite resin simplified full-crown preparations were scanned, while 60 Y-TZP crowns with occlusal retentions were milled. The composite preparations were stored for 120 days (wet environment-37°C) and randomly distributed into three groups (n=20) according to the type of composite core surface treatment. The groups were defined as: CTRL (control: No treatment), EFB (extra-fine diamond bur [25µm]), and CB (coarse diamond bur [107µm]). The grinding was performed with an adapted surveyor standardizing the speed and pressure of the grinding. The intaglio surfaces on the crowns were air-abraded with silica-coated alumina particles (30 µm) and then a silane was applied. The crowns were cemented with self-adhesive resin cement, thermocycled (12,000 cycles; 5/55°C), stored (120 days) and submitted to a retention test (0.5mm/min). The retentive strength data (MPa) were analyzed using one-way analysis of variance and Tukey test, as well as Weibull analysis. Failures were classified as 50C (above 50% of cement in the crown), 50S (above 50% of cement in the substrate) and COE (composite core cohesive failure). Results: No statistical difference was observed among the retention values (p=0.975). However, a higher Weibull modulus was observed in the CTRL group. The predominant type of failure was 50S (above 50% of cement in the substrate composite). Conclusion: The retention of zirconia crowns was not affected by grinding using diamond burs with different grit sizes (coarse/extra-fine) or when no grinding was performed

Análise dos acidentes e complicações em cirurgias de terceiros molares inferiores retidos ocorridos em Curitiba (PR) / Analysis of accidents and complications in surgical removal of impacted mandibular third molars occurred in Curitiba/PR

A retenção dentária, principalmente dos terceiros molares, apresenta-se como um problema de frequência relevante que atinge indivíduos de todas as camadas sociais. Em termos estatísticos, o maior volume dessas inclusões fica por conta dos terceiros molares, os infeiores com maior incidência que os superiores. Acidentes e/ou complicações são inerentes a qualquer ato cirúrgico bucal. Tendo isso em vista, o objetivo deste trabalho foi analisar os acidentes e as complicações em cirurgias de terceiros molares inferiores retidos, por intermédio de questionário direcionado aos especialistas em Cirurgia e Traumatologia Bucomaxilofacial. Neste estudo foram incluídos 28 cirurgiões-dentistas, cujo tempo médio como especialista em Cirurgia e Traumatologia Bucomaxilofacial foi de 15,1 anos, com desvio-padrão de 11,8 anos. O tempo mediano foi de 14,5 anos, o menor tempo de especialista observado foi de 1 ano e o maior foi de 47 anos. Considerando-se que o tempo como especialista apresentou grande dispersão entre os pesquisados, os resultados obtidos no estudo em relação às diversas perguntas do questionário foram analisados pelo número de casos por ano. Os resultados alcançados foram 61% de lesões do nervo alveolar inferior, 54% de hemorragia transoperatória e 50% de lesões do nervo lingual. Conclui-se com o presente estudo que o número de acidentes e complicações é baixo, tornando-se ainda menor quando o tempo do cirurgião-dentista na especialidade cresce

The dental retention, mainly of the third molar ones, is presented as a problem of relevant frequency that reaches individuals of all the social classes. In statistical terms, the highest volume of these inclusions is for account of the third molar ones, being the inferiors in higher incidence than the superiors. Accidents and/or complications are inherent to any buccal surgical act. In view of this importance, the objective of this work was to analyze the accidents and complications in surgeries of restrained inferior third molars through questionnaire directed to the specialists in Surgery and Bucomaxilofacial Traumatology. In this study 28 dental surgeons, whose average time of specialist in Surgery and Bucomaxilofacial Traumatology was of 15,1 years, with shunting line standard of 11,8 years have been enclosed. The medium time was of 14,5 years, the shortest time of observed specialist was of 1 year and the longest was of 47 years. Considering that the time as specialist presented great dispersion among the searched ones, the results gotten in the study in relation to the several questions of the questionnaire have been analyzed for the number of cases per year. The gotten results have been 61% of injuries of the inferior alveolar nerve, 54% of transoperation hemorrhage and 50% of injuries of the lingual nerve. It is concluded with the present study that the number of accidents and complications is low and getting even lower when the time of the dental surgeon in the specialty grows