Full‐Arch, Implant‐Supported Monolithic Zirconia Rehabilitations: Pilot Clinical Evaluation of Wear Against Natural or Composite Teeth

Purpose To clinically evaluate the amount of contact wear generated between full‐arch monolithic zirconia implant‐supported restorations and natural or composite antagonists, over a 1‐year period. Materials and Methods Forty‐seven teeth from clinically functional, full‐arch monolithic zirconia screw‐retained implant prostheses (FDPs) and their antagonists were investigated. The first group (“Zirconia‐E”) was opposed to natural teeth (“Enamel”), whereas the other one (“Zirconia‐CR”) was opposed to nano‐hybrid composite teeth (“Composite Resin”). Replicas of the restorations and their antagonists were obtained immediately after delivery (T0) and after 1 year of clinical service (T1). Each tooth surface was individually evaluated three‐dimensionally by software to quantify the vertical distance between the two scans (Hausdorff distance), which was considered as contact wear. Data obtained for each arch were subjected to one‐way ANOVA test and a post hoc analysis (Tukey's test) at a 5% level of significance. Furthermore, the influence of the location of the teeth (anterior or posterior) was analyzed. Minimum post hoc statistical power between statistically different groups was 99.6%. Results Mean values were 63 ± 23 μm for Zirconia‐E, 76 ± 29 μm for enamel, 70 ± 38 μm for composite resin; Zirconia‐CR had a mean value of 19 ± 4 μm and significantly differed from the other groups. Contact wear between anterior and posterior teeth differed significantly only in the composite resin arch, with a mean of 39 ± 22 μm for anterior teeth versus 101 ± 19 μm for posterior ones. Conclusions Within the limitations of this preliminary evaluation, monolithic zirconia full‐arch rehabilitations induced a clinically acceptable wear on natural and composite antagonists over a 1‐year period; they might be considered a viable solution for implant‐supported rehabilitations.