Abstract:
The external apical root resorption is often seen as an undesirable effect of
orthodontic treatment, being an iatrogenic factor predictable but not avoidable. The
aim of this study was to evaluate the factors common to patients who developed
external root resorption moderate or severe (Malmgren's grades 3 and 4), on the
maxillary incisors, during fixed orthodontic treatment in the permanent dentition. It
was selected 99 patients of both genders, who began orthodontic treatment with
fixed edgewise technique. Patients were divided into two groups: G1 - comprising 50
patients who completed treatment with no root resorption or presenting only apical
irregularities (Malmgren's grades 0 and 1), with mean initial age of 16.79 years and
mean treatment time of 3.21 years; G2 - comprising 49 patients who finished
treatment presenting external apical root resorption moderate or severe (Malmgren's
grades 3 and 4) on the maxillary incisors, with mean initial age of 19.92 years and
mean treatment time of 3.98 years. The evaluated periapical radiographs were
obtained at the beginning (T1) and at the end (T2) of orthodontic treatment. The
following variables was analyzed in this study: gender, age, treatment time, type of
malocclusion, treatment with or without extractions, previous trauma, degree of initial
resorption, shape and root length, shape of the alveolar crest; crown:root ratio; PTV-
1 apical and incisal, ANB, Wits; 1.NA; UP + UA, overjet, overbite, FMA; PFH/AFH
and H-11. Statistical analysis included chi-square tests, Fisher exact test and
independent t tests. The results demonstrated the presence of a significant difference
between the groups for the variables: treatment with or without extractions, initial
degree of root resorption, root length and crown:root ratio at the beginning, at the end
of treatment and changes with treatment, and cortical thickness of the alveolar bone.
It can be concluded that are risk factors for severe root resorption in maxillary
incisors during orthodontic treatment: presence of root resorption before the
beginning of treatment, extractions, diminished root length, crown:root ratio
decreased and thin alveolar bone at the beginning of treatment.
