Comparison of 16.9-year survival of pressed acid etched e.max lithium disilicate glass-ceramic complete and partial coverage restorations in posterior teeth: Performance and outcomes as a function of tooth position, age, sex, and thickness of ceramic material

Abstract

Statement of problem. Long-term clinical data are lacking on the comparison of the survival of adhesively luted pressed e.max lithium disilicate glass ceramic complete and partial coverage restorations in posterior dentitions and the effect that different technical and clinical variables have on their survival. Purpose. The purpose of this clinical study was to examine and compare the 16.9-year survival of posterior pressed e.max lithium disilicate glass ceramic complete and partial coverage restorations and associated clinical parameters on the outcome. Material and methods. Patients requiring either single-unit posterior defect-specific partial coverage or complete coverage restorations were recruited in a clinical private practice. The participants were offered the options of direct restorations, partial coverage cast gold, or glass ceramic (lithium disilicate) restorations. Those requiring complete coverage restorations were given the options of complete cast gold, metal-ceramic, or glass ceramic restorations. Only participants who chose glass ceramic partial and complete coverage restorations were included in the study. The overall survival of the glass ceramic restorations was assessed by the clinical factors determined at recall. The effect of various clinical parameters (type of restoration, dental arch, tooth position in the dental arch, age and sex of participant, and ceramic thickness) was evaluated by using Kaplan-Meier survival curves to account for attrition bias and other reasons for failure. The statistical significance of differences between parameters was determined using the log rank test (a=.05). Results. A total of 738 participants requiring 2392 lithium disilicate restorations in posterior teeth were evaluated. The mean age of the participants at the time of restoration placement was 62 (range: 20-99 years, 302 men and 436 women). Of 2392 units, 1782 were complete and 610 were partial coverage restorations. A total of 22 failures (bulk fracture or large chip) requiring replacement were recorded with the average time to failure 3.5 (0.02-7.9) years. The total time at risk computed for these units was 13227.9 years, providing an estimated failure risk of 0.17% per year. The 16.9-year estimated cumulative survival was 96.49%. The estimated cumulative survival of posterior complete (n=1782) and posterior partial coverage restorations (n=610) was 96.75% at 10.5 years and 95.27% at 16.9 years (P<.05). Of the 22, 16 failures were recorded for the complete coverage restorations. The total time at risk for these restorations was 10144.5 years, providing an estimated risk of 0.16 per year. The other 6 failures recorded occurred for the partial coverage restorations. The total time at risk for these restorations was 3083.5 years, providing an estimated risk of 0.19% per year. No statistically significant difference was found in the survival of posterior complete and partial coverage restorations among men and women, different age groups, or posterior tooth position in the dental arch (P>.05). The thick...

Indirect ceramic overlay restorations as a minimally invasive alternative for posterior rehabilitation

“…Medium-and long-term studies are consistent in confirming that ceramic overlay restorations have an acceptable survival in both cases exceeding 90% [3,14,15,16] . Malament et al indicate in their study a survival rate of 96.49% for 16.9 years, without finding a significant difference with the survival rate of conventional full-coverage crowns [17] . The most frequently reported failure pattern is fracture of the ceramic and/or the tooth (76.2%), followed by decementation (42.9%) and, lastly, due to caries leakage (28.6%) [3] .…”

“…However, there are still beliefs to avoid the use of lithium disilicate in the posterior dentition because of the high occlusal loads that could lead to premature fractures. Nevertheless, studies have shown that lithium disilicate adhesive overlay restorations have adequate mechanical behavior under load [2,4,7,10,17,19,20,21,22,23,24,25] . Some authors argue that increasing the thickness of the material is one of the ways to increase its strength, however, this means increased removal of hard tissue, which is sometimes counterproductive.…”

“…Furthermore, current evidence supports that reducing the thickness of lithium disilicate to 1 mm does not affect its strength and warrants the use of minimally invasive preparations [6,26] . According to a study conducted this year, restorations with thickness <1 mm and ≥1 mm performed similarly for 16.9 years [17] . Overlay-type restorations are adhesively cemented, which not only protects the restorative material, but also reinforces the hard tissue of the tooth organ [2] .…”

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

“…Long-term clinical data on the survival of pressed lithium disilicate glassceramic restorations and the effect that different technical and clinical variables have on survival are lacking. With this in mind, a series of reports emerging from one private practice [206][207][208] involving a prospective database with controls for clinical and laboratory variables reported on recall findings of a substantial patient population. The purpose of the initial clinical report in this series 206 was to examine the 10-year survival of pressed lithium disilicate glass-ceramic monolithic and bilayer restorations and the relationship between clinical parameters and outcomes.…”

“…A third publication originating from the same private prosthodontic practice 208 sought to investigate the 16.9year survival of exclusively posterior pressed lithium disilicate complete and partial coverage restorations and the effects of associated parameters on clinical outcomes. Patients requiring either single-unit posterior partial coverage restorations, complete coverage restorations, or a combination were recruited.…”