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 the present 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, who had lost one of the maxillary central incisors after trauma and recieved one implant, were included.Standardized photographs of the cast models, clinical photographs and peri-apical radiographs from baseline examinationwere used to assess three-dimensional positional parameters. The contra-lateral central incisors were used as controls. Paired sample t-testand Pearson´s correlation analysis were used to analyze implant position, dimension of crownand papilla fill.Cohen’s ¿ andSpearman correlation were used to validate the PIS.The implant-supported crown was statistically longer than the contra-lateral tooth, and there was significant correlation between the oro-facial position of the implant and the crown length difference (r=.607, p=.001). The distalpapilla was significantly shorter than the mesialpapilla at implant-supported crowns (p<.0001), while this difference was not significant at contra-lateral tooth (p=.415). A significant relationship between the PIS and papilla fill was found (rs=.658, p<.0001). An implant protruding the mucosain abuccal position willresult inanincreasedimplant crown length compared to the contra-lateral 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 heightwas obviously shorter, althoughthe mesial papilla height was similar to thatof the healthy dentition.The papilla index score was tested to be a valid index for papilla fill.