Retrospective clinical study on the performance and aesthetic outcome of pressed lithium disilicate restorations in posterior teeth up to 8.3 years

Abstract

Objectives: Evaluation of cumulative survival and complication rate of monolithic lithium disilicate inlays and partial crowns performed by supervised undergraduate students up to 8.3 years of clinical service.

Materials and methods: In this retrospective clinical study 143 lithium disilicate posterior restorations (IPS e.max Press) were examined according to the FDI criteria. A standardised questionnaire was used to determine patient satisfaction. The aesthetic outcome was evaluated by dentists and dental technicians using intraoral photographs. Data were descriptively analysed. Cumulative survival and success rates were calculated using Kaplan-Meier estimation.

Results: The cumulative survival rate of lithium disilicate restorations was 97.5% after a mean service time of 5.9 years and 95.0% after 8.3 years. The cumulative success rate decreased from 94.4% after 5.9 years to 30.7% after 8.3 years. Repairs were required for 7 restorations (4.9%), and 5 (3.5%) were classified as failures. The results of the questionnaire indicate a high level of patient satisfaction. The subjective aesthetics were assessed more critically by dental technicians compared to dentists.

Conclusion: Lithium disilicate posterior restorations survived successfully up to 8.3 years when carried out by undergraduate students.

Clinical relevance: Pressed lithium disilicate glass ceramic inlays and partial crowns are reliable treatment options in posterior teeth.

Keywords: Ceramic; FDI criteria; Inlay; Partial crown; Survival rate.

Fig. 1

Partial crown 24 with pronounced marginal staining after 65 months

Fig. 2

Successful repair of the partial crown 24. Marginal staining was removed by minimally invasive interventions using a very thin bur. The resulting small cavity was filled with flowable composite due to its good rheology

Fig. 3

Kaplan–Meier cumulative survival curve for IPS e.max Press restorations in posterior teeth

Fig. 4

Kaplan–Meier cumulative success curve for IPS e.max Press restorations in posterior teeth

Fig. 5

Evaluation of patient satisfaction in terms of aesthetics and function of the indirect restorations. Patient satisfaction of one failure (total loss of the restoration) was not assessed

Fig. 6

Average values of the subjective evaluation of restorations` aesthetics by two independent dentists and dental technicians