RESUMEN
AIM: The aim of this study was to verify if the three-dimensional implant position in fresh alveolar socket may influence the maintenance of stable gingival margins around single premolar restorations with immediate implant placement. METHODS: After 16 weeks of healing, implants were loaded with single crowns. Documentation consisted in peri-apical radiographs taken: before treatment; at the time of implant placement; at the time of prosthetic rehabilitation and 12 months after the start of prosthetic function. Parameters assessed were: the presence/absence of inter-proximal papilla; the inter-implant-tooth distance (ITD); the distance from the base of the crown contact-point to the inter-dental bone crest (CPB); and the buccal-gingival tissue modifications. ITD, CPB values and the modification of buccal-gingival tissue were determined using an image processing software. RESULTS: Twenty-one healthy patients with thick gingival biotype, with a total of 21 maxillary premolars scheduled for extractions were enrolled. Following extraction, implants were immediately positioned. A 100% of implant survival rate was observed after 12 months of function. The presence of the mesial papilla was significantly correlated with the mean mesial CPB value (P = 0.0519 by means of two-tailed Mann-Whitney U-test). No significant correlation was found between the mesial papilla presence and the mean mesial ITD score (P = 0.7722 by means of two-tailed Mann-Whitney U-test). Furthermore, the presence of the distal papilla was not significantly correlated with the mean distal ITD and CPB values: scores of 0.7195 and 0.8225 were calculated respectively. CONCLUSION: In the premolar area, the relationship between the presence of a complete inter-proximal papilla and ITD parameter was not significant (P > 0.05). The relationship between the presence of a complete inter-proximal papilla and CPB parameter still remain unclear. Nevertheless, a more large sample size is required to confirm this trend. Moreover, it was observed that the buccal-gingival tissue withdrew in the range 0-1 mm after 1 year of prosthetic function.