Influência da espessura e opacidade dos materiais restauradores na reabilitação estética de dentes escurecidos

Abstract

Aim: To evaluate the thickness and opacity influence of the resin and ceramics on restoration of darkened dental fragments. Material and methods: 150 specimens were prepared, being 90 with lithium disilicate ceramic in the BL-1 and 0 colours (IPS E.max Press – Ivoclar Vivadent), and 60 with composite resin in the BL-L colour (IPS Empress Direct - Ivoclar Vivadent), with size 4mmx4mm and thickness ranging from 0.7mm, 1mm and 1.2mm. In order to obtain the 150 dental fragments in the sizes of 4mm x 4mm x 3mm (width x length x thickness), 150 human premolars teeth were used. (Article 1): The groups were assigned according into material used and your respective opacity levels: E.max HT; E.max LT; E.max MO; IPS Empress Direct of Resin; IPS Empress Direct of Enamel. All the opacity levels was tested in three thicknesses (0.7mm, 1mm and 1.2mm), resulting into 15 groups (n = 10 per group). The dental fragments were pigmented and, thereafter, had their colour has been evaluated by spectrophotometry. The specimens were randomly assigned among the 15 groups for the cementation of ceramic and resinous laminates with glassy photoactivated cement (Rely X venner - 3M ESPE). Then follow, the restored entirety were evaluated by spectrophotometry, to compare the colorimetric data of the darkened fragment before and after the restoration. (Article 2): A specimen test of each group, typical of the average value of the respective group, was chose to compose the digital pictures frame rated by 200 individuals (professionals and laymen), who selected the clearest and darkest specimen. All data were tabulated and statistically analysed, with a significance level of 5%. Results: In Article 1, higher values of total colour variation (ΔE) were observed for dentin resin, followed by LT and MO ceramics. Regarding thicknesses, it is observed that for the three ceramic opacities, the thickness of 1.2mm showed ΔE significantly higher than the others. On the other hand, dentin resin showed similarity in ΔE related to thicknesses of 1.2 and 1.0mm; which were more highted compared to the thickness of 0.7mm. In relation to Article 2, the concordance between professionals and laymen was considered faint, according Kappa coefficient. Conclusions: The better thickness/opacity arrangements to mask a darkened substrate were watched for the thickness of 1.2mm associated with low translucency and medium opacity, or even by for dentin resin; the instrumental evaluation, luminosity value (L*), showed coherence with the visual evaluation of the professionals, nevertheless, professional and non- professional present different perceptions, mainly in regard to dark.