Cone-beam computed tomography evaluation of bone plate and root length after maxillary expansion using tooth-borne and tooth-tissue-borne banded expanders

• Published in: American journal of orthodontics and dentofacial orthopedics 2018-10, Vol.154 (4), p.504-516
• Main Authors: Lemos Rinaldi, Mariana Roennau, Azeredo, Fabiane, Martinelli de Lima, Eduardo, Deon Rizzatto, Susana Maria, Sameshima, Glenn, Macedo de Menezes, Luciane
• Format: Article
• Language: English
• Subjects: Adolescent; Alveolar Bone Loss; Alveolar Process - diagnostic imaging; Analysis of Variance; Bone Plates - adverse effects; Brazil; Child; Cone-Beam Computed Tomography - methods; Dental Arch - anatomy & histology; Dental Arch - diagnostic imaging; Dentistry; Female; Humans; Imaging, Three-Dimensional; Male; Maxilla - anatomy & histology; Maxilla - diagnostic imaging; Molar - anatomy & histology; Molar - diagnostic imaging; Orthodontic Anchorage Procedures - adverse effects; Orthodontic Anchorage Procedures - instrumentation; Orthodontics, Corrective - instrumentation; Orthodontics, Corrective - methods; Palatal Expansion Technique - adverse effects; Palatal Expansion Technique - instrumentation; Tooth - anatomy & histology; Tooth - diagnostic imaging; Tooth Root - anatomy & histology; Tooth Root - diagnostic imaging; Tooth Root - pathology
• ISSN: 0889-5406; 1097-6752
• DOI: 10.1016/j.ajodo.2017.12.018

The objective of this research was to evaluate the buccal bone plate and root length of maxillary permanent first molars using cone-beam computed tomography after maxillary expansion with different activation protocols. Cone-beam computed tomography images of growing patients were obtained from the orthodontic department of Pontifical Catholic University of Rio Grande do Sul in Brazil. The groups were Haas-type 2/4 turns, Haas-type 4/4 turns, hyrax-type 2/4 turns, and hyrax-type with alternate rapid maxillary expansions and constrictions (alt-RAMEC) 4/4 turns a day. Tooth length, periodontal insertion, alveolar bone thickness, and intermolar distances were evaluated. The data at the start of treatment and 6 months later were compared using generalized linear models. The intergroup differences were determined by univariate analysis of variance with the Bonferroni adjustment. Tooth length was significantly shortened after expansion in all groups (−0.28 to −0.51 mm), except for the alt-RAMEC group. Bone level variables (bone level and bone level at the tooth tip) changed statistically in all groups, except for the Haas 4/4 turns group. There was significant periodontal attachment loss after rapid maxillary expansion with the hyrax/alt-RAMEC (5.09 mm). The hyrax/alt-RAMEC and hyrax groups had more dehiscences, fenestrations, and exposures of the root. The consequence of rapid maxillary expansion using the hyrax was alveolar bone resorption, especially in the hyrax/alt-RAMEC group, whereas the Haas expander caused mild root resorption. •We evaluated buccal bone plate and maxillary first molar root length after RME.•The hyrax groups showed more alveolar bone resorption.•The hyrax/alt-RAMEC group also showed more attachment loss.•The hyrax groups had more dehiscences, fenestrations, and root exposure.•The Haas group had more root resorption.