Clinical and radiographical evaluation of CAD-CAM crowns with and without deep margin elevation: 10-year results

Current in vitro and short-term clinical studies suggest that deep margin elevation (DME) is a suitable approach to relocate subgingival margins to a supragingival position. However, long-term clinical results are lacking.

The purpose of this retrospective multicenter practice-based study was to assess the long-term clinical performance and periodontal health of teeth restored with computer-aided design and computer-aided manufacturing (CAD-CAM) crowns with or without DME.

Patients who had received CAD-CAM lithium disilicate (LD) crowns with or without DME in 2013 were invited for a follow-up appointment. When indicated, DME had been performed using resin-based restoration. A total of 275 LD crowns had been fabricated chairside, and 151 crowns had been laboratory milled. The crowns had been cemented with 3 different adhesive and self-adhesive resin cements. Clinical and radiographical assessment of the crowns and supporting periodontal structures were performed according to the modified United States Public Health Service (USPHS) criteria. Linear mixed effect models were used to assess the effect of the follow-up time on repeated measurements (α=.05). The Kaplan-Meier survival analyses were determined.

A total of 380 patients with 426 crowns (153 with DME and 273 without DME) were examined with a follow-up period of 10 years. Overall, 15 teeth with secondary caries, 4 with loss of vitality, 4 crown fractures, and 3 crowns with lost retention were observed. The DME profile was rated good in 74%, acceptable in 17.5%, and poor in 8.5% of crowns. The periodontal parameters of teeth with DME were not significantly different from teeth without DME (P>.05). The 10-year survival rates for the DME and without DME groups were 95.8% and 94.7%, respectively, while the 10-year success rates for the DME and without DME groups were 94.1% and 93%, respectively.

The use of DME and lithium disilicate crowns as well as adhesive bonding is considered a safe and reliable treatment option. The integrity of periodontal tissue was not affected by the DME or by the crowns.