OBJECTIVEThis prospective study was to observe the correlation between the mesial papilla's height of single implant-supported maxillary central incisor and the distance from the base of the contact point to the alveolar bone crest.

METHODS56 patients involved in single implant-supported maxillary central incisor were included in this study. The distances from the base of the contact point to the alveolar bone crest in the digital periapical film of maxillary central incisor were measured using the software Planmeca Dimaxis Version 3.3.2. The time of measurements were as follows: The pre-surgical and post-surgical periods, before and after the crown installation, the follow-up examination of more than 0.5 year. To analyze the factor of influencing distance, and the correlation between the distance and the height of gingival papilla during the whole restored period. Correlation analysis between the distance and the height of gingival papilla during the whole restoration was done by the statistical software SPSS 12.0.

RESULTSThe results demonstrated that the ratio of esthetic papilla can achieve 54.5% at the crown installation and 95.5% at the follow-up examination when the distance was between 3 mm and 5 mm. When the distance was between 5 mm and 6 mm, they dropped to 30.0% and 75.0%, respectively. However, when the distance increased to above 7 mm, the papilla could hardly be in an esthetic outcome. There was a significant change of the distance was found during the periods from the post-surgery to pre-restoration, and the scope of the changes was between -0.13 mm and 0.46 mm. A negative correlation was found between the distance and the index of papilla. The correlation coefficient r was -0.715 (P < 0.01).

CONCLUSIONIt is proposed that the pre-surgery distance of maxillary central incisor from the base of the contact point to the alveolar bone crest can be used as one of the important reference indexes to assess and predict the height conditions of gingival papilla.