Retrospective study of glass-ceramic single tooth restorations after up to 15 years

Introduction: Glass-ceramic single-tooth restorations count among the standard treatments in dental practice at present owing to their good esthetics, biocompatibility and survival rates. The aim of this study was to investigate the occurrence of various long-term complications based on data collected from a general dental practice. Material and methods: A retrospective analysis of 1132 posterior single-tooth restorations made of Empress 2 and IPS e.max ceramic from 251 patients was performed. The restorations were placed between 2000 and 2015 by a single dental practitioner in a private general dental practice. The minimum observation period was 2 years. The patient records were examined for the following complications: fracture, root canal treatment, periodontal complications, occlusal adjustment procedures to correct occlusal interferences, postoperative hypersensitivity, secondary caries and decementation. The statistical analysis was based on the ceramic used (Empress 2 and IPS e.max) and the type of restoration (inlay, partial crown, or crown). Results: Twelve of the 769 Empress 2 and 3 of the 363 IPS e.max restorations failed due to bulk fracture. There was no significant difference between the materials (p = 0.411). Crowns displayed a significantly higher fracture rate compared to inlays or partial crowns (p = 0.02 and p = 0.04), irrespective of material. Empress 2 restorations showed a significantly higher incidence (3.6 %) of premature occlusal contacts requiring adjustment compared to IPS e.max restorations (1.4 %) (p = 0.037). No correlation between occlusal adjustment procedures and fracture was observed (p = 0.426). Empress 2 crowns had a significantly higher probability of decementation (p 0.001) compared to Empress 2 inlays or partial crowns. Teeth with IPS e.max restorations exhibited significantly more postoperative hypersensitivitity (p 0.001) and required root canal treatment significantly more frequently (p = 0.041) than teeth with Empress 2 restorations. Periodontal complications occurred significantly more often in teeth with IPS e.max crowns than in teeth with IPS e.max inlays or partial crowns (p = 0.005). The incidence of secondary carious lesions was not significantly higher neither with respect to material nor type of restoration. Conclusion: Both glass-ceramic materials are suitable for everyday use in dentistry; IPS e.max and Empress 2 restorations demonstrated good long-term clinical results and an acceptable amount of complications. The most common complications were postoperative hypersensitivity, fractures and peri-odontal complications. The number of complications was higher for crowns than for inlays or partial crowns. Keywords: complications, Empress 2, fracture rate, glass-ceramic, IPS e. max, long-term performance, retrospective, single-tooth restorations