No universal dimension of the biologic width appears to exist .
BACKGROUND Consideration of the biologic width in restorative dentistry seems to be important for maintaining periodontal health .
OBJECTIVE To evaluate the dimensions of the biologic width in humans .
Effect of posterior crown margin placement on gingival health.
STATEMENT OF PROBLEM The clinical impact of  posterior crown margin placement on gingival health has not been thoroughly quantified . PURPOSE This study evaluated the effect of posterior crown margin placement with multivariate analysis . MATERIAL AND METHODS Ten general dentists review ed 240 patients with 480 metal-ceramic crowns in a prospect i ve clinical trial . The alloy was r and omly selected from 2 high gold , 1 low gold , and 1 palladium alloy . Variables were the alloy used , oral hygiene index score before treatment , location of crown margins at baseline , and plaque index and sulcus bleeding index scores recorded for restored and control teeth after 1 year . The effect of crown margin placement on sulcular bleeding and plaque accumulation was analyzed with regression models ( P<.05 ) . RESULTS The probability of plaque at 1 year increased with increasing oral hygiene index score before treatment . The lingual surfaces demonstrated the highest probability of plaque . The risk of bleeding at intrasulcular posterior crown margins was approximately twice that at supragingival margins . Poor oral hygiene before treatment and plaque also were associated with sulcular bleeding . Facial sites exhibited a lower probability of sulcular bleeding than lingual surfaces . Type of alloy did not influence sulcular bleeding . CONCLUSION In this study , placement of crown margins was one of several parameters that affected gingival health
No universal dimension of the biologic width appears to exist .
BACKGROUND Consideration of the biologic width in restorative dentistry seems to be important for maintaining periodontal health .
OBJECTIVE To evaluate the dimensions of the biologic width in humans .