Partial Glass-Ceramic Posterior Restorations with Margins Beyond or Above the Cemento-Enamel Junction: a Case-Controlled Clinical Study

Rijksuniversiteit Groningen, Groningen, Netherlands

Objective: This case-controlled clinical study aimed to investigate the survival and success of partial indirect lithium disilicate restorations with margins extending above or beyond the cemento-enamel junction (CEJ).

Material and Methods: Patients who received partial indirect lithium disilicate restorations with Immediate Dentin Sealing (IDS) between January 2008 and October 2018 were included. All restorations were placed in a single general dental practice according to a set protocol. The impact of multiple predictor variables on survival was assessed and the modified USPHS criteria were used to evaluate the quality of survival.

Results: 1146 partial indirect lithium disilicate restorations were evaluated in 260 patients over an average period of 7.5 years. The cumulative survival and success rates were 97.3% and 95.3% respectively. Margins extending beyond the cemento-enamel junction did not increase the risk of survival failure (p=0.43). However, factors such as 'high caries risk', 'male' gender, and 'non-vital teeth' significantly increased the risk of restoration failure with hazard ratios of 3.26, 2.95, and 2.54 respectively (p<0.001). Restorations with longer clinical service time (>6 years) exhibited slightly worse marginal adaptation, reduced polished surface, and increased likelihood of surface staining (p<0.001).

Conclusion: Partial lithium disilicate restorations exhibit an excellent survival rate of 97.3%. The location of the margin, beyond or above the CEJ, does not significantly influence clinical survival in the studied population. Partial lithium disilicate restorations are a viable treatment option for severely biomechanically compromised teeth, but notable risk factors for restoration survival failure include a high caries risk, males and non-vital teeth.

Funding/Conflict of Interest: This study was not funded and there is no conflict of interest.

Keywords: immediate dentin sealing, lithium disilicate, adhesive, partial indirect restoration, posterior

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