Influence of Implant Position on Clinical Crown Length and Peri-implant Soft Tissue Dimensions at Implant-Supported Single Crowns Replacing Maxillary Central Incisors

The aims of this study were to evaluate the influence of implant position on clinical crown length and marginal soft tissue dimensions at implant-supported single crowns of maxillary central incisors and to validate the papilla index score (PIS). Twenty-five patients were included. Standardized and clinical photographs and periapical radiographs from baseline were used to assess three-dimensional positional parameters. The contralateral central incisors were used as controls. Paired sample t test and Pearson correlation analysis were used to analyze implant position, dimension of crown, and papilla fill. Cohen κ and Spearman correlation were used to validate the PIS. The implant-supported crown was statistically significantly longer than the contralateral tooth, and there was significant correlation between the orofacial position of the implant and the crown length difference. The distal papilla was significantly shorter than the mesial papilla at implant-supported crowns, but this difference was not significant at the contralateral tooth. A significant relationship between the PIS and papilla fill was found. An implant protruding the mucosa in a buccal position will result in an increased implant crown length compared to the contralateral tooth. Minor buccal angulations of the implant could be corrected with customized angulated abutments and did not necessarily result in an increased crown length. The distal implant papilla height was obviously shorter, although the mesial papilla height was similar to that of the healthy dentition. The PIS was found to be a valid index for papilla fill.