Clinical effect of resin hybrid ceramic onlay in repairing posterior tooth defects

To investigate the clinical effect of restoration of posterior teeth with machinable CAD/CAM resin hybrid ceramic (VITA Enamic) onlays after root canal treatment.

136 posterior teeth restored after root canal treatment in our hospital were selected as the research subjects. The posterior teeth were restored chairside with CAD / CAM ceramic onlays to recover occlusion relation and protect residual dental tissues. With 68 teeth in each group, one group was restored with a machinable CAD / CAM resin hybrid ceramic (VITA Enamic) while the control group received zirconia-reinforced lithium silicate ceramic (VITA Suprinity). Before bonding, all the onlays were examined for good adjacency, fitness and occlusion, and then the adhesive surface was etched with hydrofluoric acids. After isolating the rubber dams in the mouths, the onlays were bonded with dual-cure resin cements. The patients were followed up for 24 months to compare the degree of prosthesis integrity, marginal fitness, gingival health, dental integrity, color matching and secondary caries.

After restoration, all the onlays were in harmony with the surrounding teeth with good aesthetic effect and suitable marginal fit. Two years later, there were no significant differences in the marginal fitness, gingival health, dental integrity or secondary cavities between the two groups (P > 0.05). In terms of restoration integrity, the VITA Enamic onlays (100%) were intact and displayed good retention. The group that received VITA Suprinity had 6 onlay (9.23%) fractures and a success rate of 90.77%; however, the residual dental tissues did not break. The difference of prosthesis integrity between the two groups was statistically significant (χ² = 4.45, P < 0.05).

Chairside CAD/CAM resin hybrid ceramic (VITA Enamic) onlays can quickly restore posterior teeth after root canal therapy and better protect the residual dental tissue.