Volume fraction and location of voids and gaps in ultraconservative restorations by X-ray computed micro-tomography

Abstract

Background: Volume fraction (Vf) and location of internal voids and gaps in relation to material

type and cavity dimensions in ultraconservative restorations were investigated in this study.

Materials and Methods: Forty-eight round cavities of 1.3 mm mean diameter and 2.6 mm mean

depth were made on buccal and lingual surfaces of recently extracted human teeth. These were fi lled

and thermocycled with two low viscosity composites (AeliteFlo LV [AF], PermaFlo [PF]), one high

viscosity composite (Aelite aesthetic enamel [AA]) and one glass-ionomer (GCFuji IX GP). X-ray

microtomography, following a specifi c procedure, was applied to all cavities before and after their

restoration, using SkyScan-1072 microtomographer. Vf percent (Vf%) and location of voids and gaps

were recorded and analysed statistically at a = 0.05. Kruskal-Wallis nonparametric analysis of variance,

post-hoc analysis, Mann-Whitney test, Spearman’s correlation analysis were used to analyze data.

Results: Cavities fi lled with AF and PF showed signifi cantly lower Vf% of voids and gaps than all other

restorations (P < 0.05). Only for the cavities fi lled with AA, cavity width and depth was signifi cantly

correlated with Vf% (P < 0.05). 50-75% of the fi lled cavities contained internal voids regardless of

the restorative material (P > 0.05). The proportion of cavities with gaps at the bottom and side

walls was lower in those fi lled with AF and PF (P < 0.05).

Conclusion: Cavities fi lled with low viscosity composites presented the lowest amount of internal

voids and gaps. Glass-ionomer and high viscosity composite restorative materials showed the highest

amount of interfacial gaps. Only in the high viscosity composite restorations the amount of voids

and gaps correlated with the cavity depth, width and volume.

Key Words: Cavity preparations, composite resin, dental, dental marginal adaptations, microcomputed tomography, x-ray