Biological evaluation of indirect restorations in endodontically treated posterior teeth with deeply located proximal margins following deep margin elevation versus surgical crown lengthening: a randomized controlled trial.

OBJECTIVE: The current clinical trial was conducted to evaluate the effect of proximal indirect restorations in endodontically treated posterior teeth with deeply located margins following deep margin elevation compared to surgical crown lengthening. MATERIAL AND METHODS: Deep proximal cavities in endodontically treated posterior teeth were randomly assigned into two groups; deep margin elevation (DME) or crown lengthening (CL). The clinical attachment level (CAL), probing depth (PD), bleeding on probing (BOP), crestal bone level (CBL), and secondary caries were evaluated at the baseline, 1, 3, 6, 9, and 12 months. RESULTS: A total of 20 proximal cavities were included in the study; there was no significant difference between the two groups regarding mean CAL values at the baseline and 1 month, while there was a significant difference between the two groups in all other periods. Regarding the PD, there was no statistical significance between the two groups except at 9 and 12 months, where CL showed higher mean PD values than DME. There was no statistically significant difference in BOP or CBL between the two groups. CONCLUSIONS: DME and CL are considered clinically successful with favorable biologic responses. CLINICAL RELEVANCE: The deep margin elevation approach could provide a more conservative solution when relocating deeply seated cervical margins in a more coronal position. DME reduced the number of visits and time needed for the restoration of endodontically treated teeth. Surgical crown lengthening remains a gold standard procedure in the re-establishment of the supracrestal tissue attachment, especially in cases where cervical margins are beyond the elevation capacity.

Different Designs of Deep Marginal Elevation and Its Influence on Fracture Resistance of Teeth with Monolith Zirconia Full-Contour Crowns.

Background and objectives: Even with the demand for high esthetics, the strength of the material for esthetic applications continues to be important. In this study, monolith zirconia (MZi) crowns fabricated using CAD/CAM were tested for fracture resistance (FR) in teeth with class II cavity designs with varying proximal depths, restored through a deep marginal elevation technique (DME). Materials and Methods: Forty premolars were randomly divided into four groups of ten teeth. In Group A, tooth preparation was conducted and MZi crowns were fabricated. In Group B, mesio-occluso-distal (MOD) cavities were prepared and restored with microhybrid composites before tooth preparation and the fabrication of MZi crowns. In Groups C and D, MOD cavities were prepared, differentiated by the depth of the gingival seat, 2 mm and 4 mm below the cemento-enamel junction (CEJ). Microhybrid composite resin was used for DME on the CEJ and for the restoration of the MOD cavities; beforehand, tooth preparations were conducted and MZi crowns were and cemented using resin cement. The maximum load to fracture (in newtons (N)) and FR (in megapascals (MPa)) were measured using the universal testing machine. Results: The average scores indicate a gradual decrease in the load required to fracture the samples from Groups A to D, with mean values of 3415.61 N, 2494.11 N, 2108.25 N and 1891.95 N, respectively. ANOVA revealed highly significant differences between the groups. Multiple group comparisons using the Tukey HSD post hoc test revealed that Group D had greater DME depths and showed significant differences compared with Group B. Conclusions: FR in teeth decreased when more tooth structure was involved, even with MZi crowns. However, DME up to 2 mm below the CEJ did not negatively influence the FR. Strengthening the DME-treated teeth with MZi crowns could be a reasonable clinical option, as the force required to fracture the samples far exceeded the maximum recorded biting force for posterior teeth.