Dimensions of hard and soft tissue around adjacent, compared with single-tooth, zirconia implants.

Preservation or regeneration of the papilla has always been a challenge around consecutive implants or with implants next to teeth, and many studies have evaluated the papilla's behaviour and patterns based on surgical technique and prosthetic design, though evidence about its behaviour around zirconia implants is scarce. The aim of this study was to evaluate papilla behaviour between implants and teeth (tooth-implant group) and between consecutive implants (implant-implant group). Ninety patients with 122 zirconia implants (Straumann® PURE Ceramic Implant) were examined at the one-year follow up. We measured the effect of the distance: first from the base of the contact point of the crowns to the contact with bone at the implant site (D1); secondly, to the contact with the bone at the neighbouring tooth or implant site (D2); and thirdly on the papillary deficit (D3). In both the tooth-implant group and the implant-implant group, D1 and D2 correlated significantly with the papillary deficit (D3), whereas D2 was the major determinant factor (Spearman's rho=0.60). In both groups, when D1 and D2 were <6mm, the papilla was present every time. The papillary deficit was significantly greater in the tooth-implant group than in the implant-implant group (p=0.048). We conclude that the ideal distance from the base of the contact point to the bone contact at the implant and to the bone contact at the adjacent tooth in both groups is <6mm. The height of the bone on the teeth adjacent to implants has a significant impact on that of the papilla.