Construção e validação de dispositivo de transluminação dental para avaliação de trincas geradas pela contração de polimerização

Abstract

The aim of this study was to develop and validate the device of the transillumination method for evaluating the cracking generated by polymerization shrinkage and to analyze the effect of the resin composite type when used in molar teeth with large structural loss. Twenty molars were collected and received MOD cavity preparation and were randomly divided into 2 groups (n = 10): a) Z100- Filtek Z100 (3M ESPE) using incremental oblique filling technique; b) XTRA- X-Trafil “Bulk-fil” VOCO (Cuxhaven, Germany). Both composites were used following manufacture’s. For detecting the crack using transillumination method was developed the specific device that stabilize the professional camera for capturing images with standard parameters. The tooth is stabilized into the dedicated device space and the distance between camera and the tooth is controlled by millimetric measurement. Additionally, the device has the LED light illumination in a standard position used to transilumination the samples to detect crack. The teeth were evaluated in four moments: a) intact tooth, before cavity preparation; b) after cavity preparation; c) 24 hours after filling technique; d) after storing in water for 7 days simulating hygroscopic expansion. The crack evaluation was performed using 3 aspects: a) calculating the crack size using ImageJ software; b) qualifying the crack orientation and c) qualifying the location of the crack. Z100 showed significant higher occurrence of the crack formation with higher size than XTRA (P = 0,012). The crack formation tends to be horizontal, located at the base of the cavity preparation, involving mainly the central and distal region of the cervical area of both cusps. The crack propagation was higher after hygroscopic expansion. The developed device showed to be efficient to standardize the transillumination method.