Clinical Outcomes of Monolithic Zirconia Crowns on Posterior Natural Abutments Performed by Final Year Dental Medicine Students: A Prospective Study with a 5-Year Follow-Up

Abstract

The conventional metal–ceramic is still considered the gold standard in fixed prosthetics especially in terms of longevity. Among alternative materials used, Monolithic Zirconia has shown the capability to reconcile excellent biomechanical properties with acceptable aesthetic performance and to overcome several inconveniences related to veneer restorations. This study aims to clinically evaluate Monolithic Zirconia prosthetic crowns on natural abutments in the posterior sectors, performed by final-year dental medicine students (undoubtedly with less experience in the management of such material) by the standardized California Dental Association score system evaluation, to better understand the viability of Monolithic Zirconia. This prospective study was carried out at the Dental School of the University of Bari “Aldo Moro”, Italy. Prosthetic rehabilitation included single crowns or a short pontic prosthesis with maximum one intermediate. Final-year dental students performed tooth reduction under the supervision of three expert tutors. The California Dental Association systematics (based on color, surface, anatomical shape, and marginal integrity) were adopted to evaluate the prosthetic maintenance status over time. Annual follow-up visits were re-evaluated by the same parameters each year. Univariate logistic regression analysis was performed to evaluate outcomes and the Kaplan–Meier plot to report survival. The sample consists of 40 crowns performed on 31 patients, 15 males (48.4%) and 16 females (51.6%) with an average age of 59.3 years. The clinical cases subjected to experimental study were found to be “Excellent” (1a/2a/3a/4a) in 34 cases (85%), “Acceptable” in 4 cases (10%), and “To be re-done” in 2 cases (failures) (5%). Our conclusive data support the predictability of Monolithic Zirconia restorations on natural posterior abutments at a long-term follow-up of five years, even when performed by less-experienced clinicians.

Clinical outcomes of tooth-supported monolithic zirconia vs. porcelain-veneered zirconia fixed dental prosthesis, with an additional focus on the cement type: a systematic review and meta-analysis

“…The full-text reports of the remaining 114 articles led to the exclusion of 40 articles because they did not meet the inclusion criteria: shorter follow-up report with an already published longer follow-up report with the same cohort group of patients ( n = 16), not enough or no clinical outcome data available ( n = 4), no separate information on clinical outcomes between tooth- and implant-supported prostheses ( n = 3), endocrowns ( n = 3), inlay-retained restorations ( n = 3), more than one type of restoration material included in the study, but no separate data on the zirconia restorations ( n = 1), restorations made of zirconia-reinforced lithium silicate ( n = 1), technical complications not investigated ( n = 1), restorations in abutment teeth for partial removable dentures ( n = 1), 3D-printed zirconia crowns ( n = 1), no follow-up ( n = 1), not providing clinical information regarding the number of prosthesis, but the number of prosthetic units ( n = 1), lab study ( n = 1), single-retainer prostheses ( n = 1), partial crowns ( n = 1), and study of post-cementation occlusion with no follow-up ( n = 1). Thus, 74 publications were included in the review [ 13 – 86 ].

Fig.

…”