Clinical Evaluation of Ceramic Single Crowns

Long-term, practice-based clinical evaluations of various contemporary ceramic crown res­torations from multiple practitioners are limited.

A study by Dhjma et al evaluated the clinical performance of ceramic single crowns after at least 5 years and identified factors that influence their clinical performance. Included in the study were ceramic single crowns that had been placed at the Mayo Clinic and in function since 2005. The restorations were examined clinically, radiographically, and with photographs. Clinical evaluation used criteria modified from United States Public Health Ser­vices criteria. The ceramic systems evaluated were bilayer and monolayer. The study involved 59 patients (41 women, 18 men) with 226 single teeth and im­plants restored with single ce­ra­mic crowns. The mean duration from insertion date to study ex­amination date was 6.1 years. Thirteen restorations (6%) were replaced at a mean 3.3 years after insertion date (range, 0.1 to 6.1 years). Estimated replacement-free survival rates (95% confidence interval [CI]; number of teeth/implants still at risk) at 5 years after insertion date were 95.1% (95% CI, 92.2 to 98.1; 153) and at 10 years were 92.8% (95% CI, 89.1 to 96.8; 8). The study found that the most common reason for replacement was fracture to the core of layered ceramic crowns in the posterior areas of the mouth. The most commonly used luting agent was resin-modified ionomer cement. Most res­torations exhibited clinically ac­ceptable marginal integrity, shade, no caries recurrence, and no periapical pathology.

The study concluded that the clinical performance of ceramic single crowns at 5 and 10 years supports their application in all areas of the mouth. However, due to the finding that the majority of fractures to the core occurred early in the lifetime of layered ceramic posterior crowns, consideration of other monolithic cera­mic systems for posterior crowns is advised.

(Source: Journal of Pros­thetic Dentistry, February 2014, Volume 111)