Site-specific Multivariate Analysis of Periodontal Attachment after Tooth Crowning

Objectives: In order to overcome problems with correlation of multiple observations within the oral cavity, an ecological approach of data reduction has frequently been advocated, accepting immediate loss of valuable information. In contrast, the present study was conducted to determine the influence of intracrevicular crown margins on the level of periodontal attachment using multivariate analyses of site-specific data. Methods: In 11 periodontally healthy patients 44 maxillary anterior teeth and/or premolars had to be crowned. A total of 36 teeth (82%) had, after crown placement, an intracrevicular crown margin (mean ± standard deviation 0.57 ± 0.47 mm). 39 teeth without restorations served as a control. Immediately after incorporation as well as after 3, 6, 9 and 12 months periodontal examinations were carried out. Results: Gingival thickness was determined sonometrically and averaged 1.25 ± 0.40 mm. Mean periodontal probing depth as measured with an electronic probe was 1.80 ± 0.54. Twelve months later, crowned teeth had experienced a mean attachment loss of 0.17 ± 0.99 mm as compared to an attachment gain of 0.18 ± 0.46 mm at control teeth. At test teeth, the gingival margin had receded a mean 0.43 ± 0.74 mm. In multivariate analyses considering the correlated structure of the data employing Generalized Estimating Equation methods, crown placement was identified a major factor for attachment loss (p<0.001) and development of gingival recession (p=0.016). In addition, a shallow probing depth as well as a narrow band of gingiva negatively influenced the level of periodontal attachment. Conclusions: Present results point to the importance of a more detailed periodontal diagnosis of the dentogingival region before placement of artificial crowns.