Root resorption, marginal bone support and clinical crown length in orthodontically treated patients

Abstract

The study was carried out on 12 patients orthodontically treated with the edgewise technique in the upper jaw. The incidence and degree of root resorption, changes in marginal bone support and clinical crown length in the treated upper jaw were compared with the corresponding findings in the untreated lower jaw. Apical root resorption was found in 50% of the teeth in the upper jaw. In 88% of these teeth the resorption was less than 2 mm. A statistically significant reduction of the marginal bone was found for the upper jaw but not for the lower jaw. Large intra- and interindividual variations were observed. In only three patients was the reduction 0.3 mm or more. There was a significant increase in clinical crown length for the lower jaw, but not for the upper jaw. Variations were found from mean lengthening of 1.06 mm to shortening of 0.56 mm.