Interdental bone changes after orthodontic treatment: A 5-year longitudinal study

Abstract

Two groups of 20 adolescents, one treated and one untreated, were followed longitudinally for 5 years. The interdental alveolar bone level was estimated as the distance between the cementoenamel junction and the alveolar bone crest on bite-wing radiographs of the upper and lower premolars and molars on three occasions, the first at the start of treatment, the second after 2.8 years, and the third at the end of the 5-year study period. Between the first and second examination, the subjects in the treatment group were orthodontically treated in the upper arch with magnets and superelastic coils succeeded by straight-wire appliances in both arches. At the start of this study, no significant difference in alveolar bone level between treated and untreated groups was found. It was demonstrated that there was a small but significant decrease in interdental alveolar bone support ranging between 0.1 and 0.5 mm during the 5-year observation period both in the treated and untreated group. Neither group had any sites with clinically significant bone loss, i.e., a distance > 2 mm between the cementoenamel junction and the alveolar bone crest. The treated group exhibited a statistically significantly larger increase of cementoenamel junction and the alveolar bone crest distance at the mesial surfaces of the first and second maxillary molars than did the untreated group. This was thought to be a direct consequence of the orthodontic treatment, either as a result of band placement, tipping, or extrusive effects, or due to tooth morphology leading to plaque accumulation. (Am J Orthod Dentofacial Orthop 1998;114:25-31)