Evaluation of the clinical performance of endocrown and overlay restorations: A 4-year retrospective study

Abstract

Objectives: This retrospective study aimed to evaluate and compare the clinical performance, plaque indices, and cemented surface areas of feldspathic ceramic endocrown and overlay restorations in endodontically treated premolars and molars over a 2- to 4-year follow-up.

Methods: Fifty-one restorations (24 endocrowns, 27 overlays) delivered between January 2019 and September 2022 were examined. All were fabricated in a single session using CEREC system (Omnicam AC scanner, CEREC Software v3.85, and MCXL milling unit; Sirona Dental Systems GmbH, Bensheim, Germany) from feldspathic ceramic blocks (CEREC Blok PC; Sirona Dental Systems GmbH, Bensheim, Germany) and cemented with a dual-cure adhesive resin cement (G-CEM LinkForce; GC Corporation, Tokyo, Japan). Clinical performance was assessed using modified FDI criteria, including esthetic, functional, and biological parameters. Plaque index was recorded, and cemented surface area was measured using archived STL files. Statistical analyses included the Mann-Whitney U test, chi-square test, Fisher's exact test, and two-way ANOVA (p < 0.05).

Results: All endocrown and overlay restorations showed a 100 % survival rate, with no failures. No significant differences were found in esthetic, functional, or biological performance (p > 0.05). Plaque index scores were similar (p = 0.253), but a strong negative correlation was observed between plaque accumulation and periodontal response (Spearman's rho = -0.846, p < 0.001). Endocrowns had a significantly larger cemented surface area than overlays (p = 0.020), but this did not impact clinical success.

Conclusions: Endocrowns and overlays provided reliable, minimally invasive treatment options for endodontically treated premolars and molars, ensuring high survival rates. Although endocrowns presented a larger cemented surface area, overlays showed similar success, supporting a conservative approach. Periodontal health was not significantly affected by restoration type, but clinical success was influenced by patient hygiene (clinicaltrials.gov ID: NCT06734806).

Clinical significance: Endocrowns and overlay restorations fabricated from feldspathic and cemented with a dual-polymerized resin cement used with a bonding agent can be safely applied in a single session for endodontically treated posterior teeth.

Keywords: Ceramics; Clinical trial; Dental cements; Dental marginal adaptation; Dental materials; Dental restoration failure; Dental restoration, permanent.