Onlays/partial crowns versus full crowns in restoring posterior teeth: a systematic review and meta-analysis

Abstract

Background Tooth-colored onlays and partial crowns for posterior teeth have been used increasingly in clinics. However, whether onlays/partial crowns could perform as well as full crowns in the posterior region was still not evaluated thoroughly. Methods A literature search was conducted without language restrictions in Pubmed, Embase, Cochrane Central Register of Controlled Trial and Web of science until September 2021. RCTs, prospective and retrospective observational studies with a mean follow-up of 1 year were selected. Cochrane Collaboration’s tool was adopted for quality assessment of the RCT. The quality of observational studies was evaluated following Newcastle-Ottawa scale. The random-effects and fixed-effects model were employed for meta-analysis. Results Four thousand two hundred fifty-seven articles were initially searched. Finally, one RCT was identified for quality assessment and five observational studies for qualitative synthesis and meta-analysis. The RCT was of unclear risk of bias while five observational studies were evaluated as low risk. The meta-analysis indicated no statistically significant difference in the survival between onlays/partial crowns and full crowns after 1 year (OR = 0.55, 95% CI: 0.02-18.08; I2 = 57.0%; P = 0.127) and 3 years (OR = 0.65, 95% CI: 0.20-2.17; I2 = 0.0%; P = 0.747). For the success, onlays/partial crowns performed as well as crowns (OR = 0.58, 95% CI: 0.20-1.72; I2 = 0.0%; P = 0.881) at 3 years. No significant difference of crown fracture existed between the two methods (RD = 0.00, 95% CI: − 0.03-0.03; I2 = 0.0%; P = 0.972). Conclusions Tooth-colored onlays/partial crowns performed as excellently as full crowns in posterior region in a short-term period. The conclusions should be further consolidated by RCTs with long-term follow-up.

Minimally invasive CAD/CAM lithium disilicate partial‐coverage restorations show superior in‐vitro fatigue performance than single crowns

“…A systematic review of clinical studies, which compared onlays and full‐coverage crowns confirmed high survival rates of 93.5% and 95.38% with no statistical difference between the groups after five years 40 . Another recently published review with meta‐analysis, found equally survival and success rates for both treatment options of onlays/partial crowns and complete crowns after one and 3 years of service 41 . Clinical long‐term studies of heat pressed and CAD/CAM‐fabricated monolithic LDS crowns, occlusal veneers with a shoulder preparation and partial‐coverage restorations reported also high survival rates of 80.1%–96.75% after 15–16.9 years, 100% after 11–13 years and 95.27% after 16.9 years of function 29,31,33,48 …”

“…40 Another recently published review with meta-analysis, found equally survival and success rates for both treatment options of onlays/partial crowns and complete crowns after one and 3 years of service. 41 Clinical long-term studies of heat pressed and CAD/CAM-fabricated monolithic LDS crowns, occlusal veneers with a shoulder preparation and partial-coverage restorations reported also high survival rates of 80.1%-96.75% after 15-16.9 years, 100% after 11-13 years and 95.27% after 16.9 years of function. 29,31,33,48 The results of the present in-vitro study showed that PCRs revealed higher failure load values compared to complete coverage crowns.…”

“…28 Ceramic bulk fractures are still the most common complication for onlays, PCRs, and crowns in clinical observations. 40,41 Failure modes after SLF revealed more bulk fractures with involvement of the fractures without involvement of the tooth for thin restorations. 24,49 In depth fractographic analysis with telltale markings such as hackle lines and compression curls showed that the fracture origin after SLF started for both types of restorations mainly from the loading area.…”

“…Nonetheless, the manufacturers' guidelines suggest a minimum restoration thickness of 1.0 mm for posterior crowns and partial‐coverage restorations to avoid restoration fractures during clinical service 34–37 . Compared to traditional crown preparations with a recommended occlusal reduction of 1.5–2 mm, minimally invasive preparation designs require a less invasive tooth preparation 38–41 . LDS CAD occlusal veneers with an average occlusal reduction of 0.4–0.6 mm in the central groove and 1.0–1.3 mm at the cusp tips presented a survival rate of 100% after 3 years 42 .…”

“…[34][35][36][37] Compared to traditional crown preparations with a recommended occlusal reduction of 1.5-2 mm, minimally invasive preparation designs require a less invasive tooth preparation. [38][39][40][41] LDS CAD occlusal veneers with an average occlusal reduction of 0.4-0.6 mm in the central groove and 1.0-1.3 mm at the cusp tips presented a survival rate of 100% after 3 years. 42 High survival rates of 96.49% after 16.9 years were also reported for LDS posterior crowns and partial-coverage restorations (IPS e.max Press) (≥1 or < than 1 mm).…”