Comparison of the Clinical Biological Width with the Published Standard Histologic Mean Values

Biologic width (BW) as defined by Cohen is the part of the supracrestal gingival tissues that occupy the space between the base of the gingival crevice and the alveolar crest; it includes the junctional epithelium and the connective tissue element. Interactions between dental crowns and the marginal periodontal tissues analyzed in many review papers concluded that the recognition of the BW, in terms of crown margin placement, is beneficial for periodontal health. Therefore, knowledge of the dimensions of the sum of the junctional epithelium and connective tissue attachment as well as the sulcus depth (SD) is of clinical relevance. The aim of the study is to compare the average SD and BW clinically measured around teeth with the standard application of a mean value of 0.69 mm and 2.04 mm, respectively, found by Gargiulo et al.in a histological study on cadavers.

Forty-two healthy patients with age ranging from 20 to 50 years presented to the Multidisciplinary Department at the Lebanese University. A total of 504 tooth sites of 126 teeth were selected and measured by two periodontists. All measurements were done on teeth requiring infiltration anesthesia for surgical, restorative, or endodontic procedures on neighboring tooth/teeth, which eliminate any ethical concerns. The SD and the distance from gingival margin to bone crest at four sites per tooth; mesial, midbuccal, distal, and midlingual/palatal were measured. Clinical, BW was calculated by subtracting SD from the distance between gingival margin to bone crest.

Friedman's ANOVA test, independent samples t-tests, and one-sample t-tests were applied. The IBM^® SPSS^® statistics 20.0 statistical package was used to carry out all statistical analyses.

The BW is statistically significantly lower than the value stated by Gargiulo et al. (2.04 mm) with a mean value of 1.13 mm, whereas the SD is statistically significantly greater than the value stated by Gargiulo et al. (0.69 mm) with a mean value of 1.96 mm.

It can be concluded that there is a need to create a patient/site-specific distance from the proposed margin of the restoration to the bone crest when restoring subgingivally fractured or carious teeth. This leads to more stable and healthy tissues when performing crown lengthening procedures. Therefore, using the term clinical, BW is more reliable and it should be used to reestablish stability and integrity of periodontal tissues around restored teeth.