Impact of access cavities on root canal preparation, restorative protocol quality, and fracture resistance of teeth

Abstract The survival of endodontically treated teeth depends on the remaining tooth structure. The aim of this study was to evaluate the impact of different access cavities on root canal preparation, restorative protocol, and fracture resistance of endodontically treated teeth. Fifty-six mandibular molars were divided into control (n=8) and experimental (n=16) groups according to access cavity: Traditional, Conservative, and Truss; and redistributed (n=8) according to instrumentation protocols: Reciproc Blue and R-motion. After, teeth were scanned in micro-CT and then filled and redistributed according to composite resin restoration (n=8): Filtek One BulkFill and Filtek Z350. A new micro-CT scan was performed to analyze the restorative material. Then, samples were submitted to fracture resistance testing and the failure pattern was determined. Data were analyzed using paired T-test, ANOVA, Tukey, and chi-square tests (α=0.05). In Truss, R-Motion promoted less transportation in different thirds of root canals. Higher percentages of voids (5.05%) and filling material (11.7%) were observed in Truss. Fracture resistance values were higher for the control group, followed by Truss, Conservative, and Traditional. The predominant failure pattern was type-II. In Truss, reciprocating instruments with smaller taper showed less canal transportation. Also, Truss provided higher values of fracture resistance, although it presented a higher percentage of voids and remaining filling material. Thus, in Truss, reciprocating files with smaller taper showed less canal transportation, and these cavities provided higher values of fracture resistance, although it presented a higher percentage of voids and remaining filling material.

Avanço tecnológico no tratamento de canais radiculares de molares: apresentação de técnica / Technological advance in the treatment of root canals of molars – presentation of a technique

Nos últimos 20 anos, considerados como “época contemporânea da Endodontia”2, ocorreu uma evolução técnica nessa especialidade de intensa magnitude que está atingindo patamares não observados em toda a sua história. Os sistemas rotatórios3 que utilizam instrumentos de níquel/titânio acionados por diferentes e sofisticados motores elétricos representam um dos avanços mais significativos dessa especialidade. Na presente apresentação de técnica, o tratamento (biopulpectomia) foi realizado em primeiro molar inferior esquerdo (36) com diagnóstico clínico de pulpite aguda irreversível. Utilizando-se o motor Dentaport ZX e instrumentos do sistema FKG RaCe, os canais radiculares foram instrumentados, proporcionando ao profissional maior ergonomia, melhor qualidade no tratamento, maior ganho de tempo e, principalmente, maior conforto para o paciente