Adaptation of Class II Vitremer restorations with and without primer: a morphometric study

The aim of this study was to assess the adaptation of Vitremer with and without primer and compare to that of Z100 with Scotchbond Multi-Purpose.

Fifty-seven Class II cavities were prepared in 32 extracted or exfoliated primary molars. The cavities were randomly assigned to one of three groups and restored as follows: group A, Vitremer with primer (20 preps); group B, Vitremer without primer (19 preps); and group C, Z100 with Scotchbond Multi-Purpose (18 preps). The restored teeth were thermocycled, embedded in acrylic resin, and sectioned. At least three 1-mm thick sections were obtained from each restoration. Adaptation of the materials was assessed by computerized quantitative morphometry using an image analysis system. In addition to the margin, the entire contact length between the tooth and the restorative material was measured. Voids were recorded separately for the base and cavity margins, and the percentage of defected length was calculated. At least three sections of each restoration were assessed. The section with the worst results was selected as the representative of the restoration.

Margin defects were present in 14% of all the restorations, equally distributed between the three groups (A, 10%; B, 16%; C, 17%). A significant difference was found between groups B and C when the percentage of defects in the base was assessed.

Vitremer without primer presented considerably fewer voids when compared with Z100/Scotchbond Multi-Purpose. Although no difference in margin defects could be observed between the three groups a better adaptation to the cavity base was seen in the Vitremer restorations without primer. This finding might be of clinical importance and should be tested in other in-vitro and in-vivo studies.