Prefabricated zirconia crown versus resin-bonded composite strip crown in the restoration of primary incisors: A 36-month parallel randomized controlled trial

Abstract

AimThe trial aimed to compare the gingival health and clinical performance of prefabricated zirconia crown (PZC) versus resin-bonded composite strip crowns (RCSC) in the restoration of primary maxillary incisors over 36-month. Materials and methodsA parallel randomized controlled trial included 200 maxillary primary incisors (100 teeth per group) restored either with PZCs or RSCS. The gingival health and plaque accumulation were assessed using gingival index (GI) and plaque index (PI) respectively. To evaluate the clinical performance, the modified United States Public Health Service (USPHS) criteria were used. Intergroup comparison was performed using a Chi-square test. Restoration longevity was assessed over the predetermined intervals using Kaplan-Meier analysis. Generalized Estimating Equation (GEE) with robust standard errors was used to test the effect of time over the changes of repeated measures. The significance level was set to 5%. ResultsThe gingival health around PZCs is significantly better than that of RCSCs after 6 months. However, at the following follow-ups, GI scores of both restorations were comparable (p > 0.05). All PZCs showed no plaque accumulation with a significant difference compared to the RCSCs over the follow-up intervals. The clinical performance of PZCs was significantly superior to that of RCSCs over the follow-ups in terms of retention and anatomical contour after 24 and 36 months. The survival rates of PZC and RCSC were 100% and 87% respectively. ConclusionsAfter 36 months, the gingival health of PZC and RCSC was comparable. The retention and anatomical continuity of PZC were superior compared to RCSC.