Changes in alveolar bone support induced by the Herbst appliance: a tomographic evaluation.
OBJECTIVE
This study evaluated alveolar bone loss around mandibular incisors, induced by the Herbst appliance.


METHODS
The sample consisted of 23 patients (11 men, 12 women; mean age of 15.76 ± 1.75 years), Class II, Division 1 malocclusion, treated with the Herbst appliance. CBCT scans were obtained before treatment (T0) and after Herbst treatment (T1). Vertical alveolar bone level and alveolar bone thickness of mandibular incisors were assessed. Buccal (B), lingual (L) and total (T) bone thicknesses were assessed at crestal (1), midroot (2) and apical (3) levels of mandibular incisors. Student's t-test and Wilcoxon t-test were used to compare dependent samples in parametric and nonparametric cases, respectively. Pearson's and Spearman's rank correlation analyses were performed to determine the relationship of changes in alveolar bone thickness. Results were considered at a significance level of 5%.


RESULTS
Mandibular incisors showed no statistical significance for vertical alveolar bone level. Alveolar bone thickness of mandibular incisors significantly reduced after treatment at B1, B2, B3, T1 and significantly increased at L2. The magnitude of the statistically significant changes was less than 0.2 mm. The changes in alveolar bone thickness showed no statistical significance with incisor inclination degree.


CONCLUSIONS
CBCT scans showed an association between the Herbst appliance and alveolar bone loss on the buccal surface of mandibular incisors; however, without clinical significance.
PhD resident, Universidade Estadual Paulista (UNESP), Department of Orthodontics, Araraquara, São Paulo, Brazil., Universidade Estadual Paulista, Universidade Estadual Paulista, Department of Orthodontics, Araraquara São Paulo , Brazil.
João Paulo
JP
Schwartz
PhD resident, Universidade Estadual Paulista (UNESP), Department of Orthodontics, Araraquara, São Paulo, Brazil., Universidade Estadual Paulista, Universidade Estadual Paulista, Department of Orthodontics, Araraquara São Paulo , Brazil.
Taisa Boamorte
TB
Raveli
Adjunct Professor, Universidade Federal do Paraná (UFPR), Department of Stomatology, Curitiba, Paraná, Brazil., Universidade Federal do Paraná, Universidade Federal do Paraná, Department of Stomatology, Curitiba Paraná , Brazil.
Humberto Osvaldo
HO
Schwartz-Filho
Professor, Universidade Estadual Paulista (UNESP), Department of Orthodontics, Araraquara, São Paulo, Brazil., Universidade Estadual Paulista, Universidade Estadual Paulista, Department of Orthodontics, Araraquara São Paulo , Brazil.
Dirceu Barnabé
DB
Raveli
D000293:Adolescent; D016301:Alveolar Bone Loss / Q000000981:diagnostic imaging*; D001938:Brazil; D054893:Cone-Beam Computed Tomography; D005260:Female; D005500:Follow-Up Studies; D005881:Gingiva / Q000000981:diagnostic imaging; D006801:Humans; D007180:Incisor / Q000000981:diagnostic imaging; D008297:Male; D008312:Malocclusion, Angle Class II / Q000000981:diagnostic imaging* / Q000628:therapy*; D008334:Mandible / Q000000981:diagnostic imaging; D016382:Orthodontic Appliance Design; D017289:Orthodontic Appliances, Functional; D010519:Periodontium / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014087:Tooth Movement Techniques