ALVEOLAR BONE LOSS OF MAXILLARY ANTERIOR TEETH IN ADULT ORTHODONTIC PATIENTS

The purpose of this study was to evaluate prevalence and severity of a lveolar bone loss in adult orthodontic patients, and to identify risk factors for such bone loss. Standardized periapical radiographs of max illary anterior teeth and cephalograms made before (T-1) and after (T- 2) treatment and treatment charts of 343 adults aged 20.0 to 70.1 year s (mean 34.5, SD 9.0) before treatment, representing groups of consecu tively treated patients from four orthodontic practices, were examined . Alveolar bone loss was calculated by subtracting the distance from t he cementoenamel junction (CEJ) to the alveolar crest (AC) at each int erproximal tooth surface from the mesial of one maxillary canine to th e mesial of the other. Changes in bone level were calculated by subtra cting the distance CEJ-AC at T-1 from the corresponding distance at T- 2. Tooth movement was calculated from measurements of superimposed tra cings of pretreatment and posttreatment cephalograms. Hygiene level wa s scored subjectively as adequate or inadequate on the basis of gingiv al appearance on posttreatment intraoral color slides. Sample means of averaged bone loss of all six anterior teeth and of the surface with the most severe bone loss per patient were 0.54 mm (SD 0.62) and 1.82 mm (SD 1.01), respectively. Only 2.5% of the patients had averaged bon e loss of greater than or equal to 2 mm, whereas 36% of the patients h ad one or more surfaces with bone loss of greater than or equal to 2 m m. Multiple linear regression analyses revealed a positive relationshi p between age and bone loss, and a negative relationship between initi al bone level and subsequent bone loss. No association was found betwe en bone loss and length of treatment, posttreatment gingival appearanc e, amount of horizontal or vertical tooth movement, or treatment with maxillary osteotomy.