Immediate periodontal bone plate changes induced by rapid maxillary expansion in the early mixed dentition: CT findings

original article Immediate periodontal bone plate changes induced by rapid maxillary expansion in the early mixed dentition: CT findings Daniela Gamba Garib1, Maria Helena Ocké Menezes2, Omar Gabriel da Silva Filho3, Patricia Bittencourt Dutra dos Santos4 DOI: http://dx.doi.org/10.1590/2176-9451.19.3.036-043.oar Objective: This study aimed at evaluating buccal and lingual bone plate changes caused by rapid maxillary expansion (RME) in the mixed dentition by means of computed tomography (CT). Methods: The sample comprised spiral CT exams taken from 22 mixed dentition patients from 6 to 9 years of age (mean age of 8.1 years) presenting constricted maxillary arch treated with Haas-type expanders. Patients were submitted to spiral CT scan before expansion and after the screw activation period with a 30-day interval between T1 and T2. Multiplanar reconstruction was used to measure buccal and lingual bone plate thickness and buccal bone crest level of maxillary posterior deciduous and permanent teeth. Changes induced by expansion were evaluated using paired t test (p < 0.05). Results: Thickness of buccal and lingual bone plates of posterior teeth remained unchanged during the expansion period, except for deciduous second molars which showed a slight reduction in bone thickness at the distal region of its buccal aspect. Buccal bone dehiscences were not observed in the supporting teeth after expansion. Conclusion: RME performed in mixed dentition did not produce immediate undesirable effects on periodontal bone tissues. Keywords: Palatal expansion technique. Periodontium. Spiral computed tomography. Objetivo: o presente estudo teve como objetivo avaliar alterações das tábuas ósseas vestibulares e linguais decorrentes da expansão rápida da maxila (ERM), em pacientes na dentição mista, por meio de tomografia computadorizada (TC). Métodos: a amostra foi constituída por exames de TC helicoidal, realizados de 22 pacientes com dentição mista, dos 6 aos 9 anos de idade (média de 8,1 anos), com atresia maxilar, tratados com expansores do tipo Haas. Os pacientes foram submetidos a tomografia computadorizada helicoidal antes da expansão e após o período de ativação de parafuso expansor, com 30 dias de intervalo entre as fases T1 e T2. A reconstrução multiplanar foi usada para medir a espessura da tábua óssea vestibular e lingual e a altura da crista óssea alveolar dos dentes posteriores decíduos e dos dentes permanentes. As alterações induzidas pela expansão foram avaliadas usando o teste t pareado (p < 0,05). Resultados: a espessura das tábuas ósseas vestibular e lingual dos dentes posteriores permaneceu inalterada durante o período de expansão, com exceção dos segundos molares decíduos, que mostraram uma ligeira redução da espessura do osso na região distal. Deiscências ósseas vestibulares não foram observadas nos dentes de suporte após a expansão. Conclusão: a ERM, realizada na dentição mista, não produziu efeitos imediatos indesejáveis sobre os tecidos ósseos periodontais. Palavras-chave: Técnica de expansão palatina. Periodonto. Tomografia computadorizada espiral. » Patients displayed in this article previously approved the use of their facial and intraoral photographs. How to cite this article: Garib DG, Menezes MHO, Silva Filho OG, Santos PBD. Immediate periodontal bone plate changes induced by rapid maxillary expansion in the early mixed dentition: CT findings. Dental Press J Orthod. 2014 May-June;19(3):36-43. DOI: http://dx.doi.org/10.1590/2176-9451.19.3.036043.oar Submitted: April 10, 2012 - Revised and accepted: August 30, 2012 Full professor, School of Dentistry — University of São Paulo/Bauru.(FOBUSP). 2 MSc in Orthodontics, University São Paulo, UNICID. 3 MSc in Orthodontics, São Paulo State University (UNESP). 4 PhD resident in Applied Dental Sciences (FOB-USP). 1 © 2014 Dental Press Journal of Orthodontics » The authors report no commercial, proprietary or financial interest in the products or companies described in this article. Contact address: Daniela Gamba Garib Faculdade de Odontologia de Bauru – Al. Octávio Pinheiro de Brisola 9-75 CEP: 17.012-901 – Bauru/SP – Brazil — E-mail: 36 Dental Press J Orthod. 2014 May-June;19(3):36-43 original article Garib DG, Menezes MHO, Silva Filho OG, Santos PBD orthopedic effects14,23 and transfers anchorage to deciduous molars and canines. A classic implant study showed that, in adolescents, skeletal effects corresponded to 35% of expansion, whereas dental effects accounted for 65%.23 On the other hand, in young children, the proportion between skeletal and dental effects was 1:1. Baccetti et al5 also observed that RME performed before the peak of skeletal maturation produced more skeletal effects than RME performed after the peak. Thus, the periodontal changes related to the orthodontic effect of RME in the early phases of mixed dentition deserve to be differentiated from those observed in late mixed dentition or even in permanent dentition. Therefore, the aim of this study was to investigate, by means of spiral CT, the periodontal bone changes of RME in early mixed dentition using deciduous teeth as anchorage. introduction During rapid maxillary expansion, orthopedic effect is produced by midpalatal suture splitting. Additionally, a dental effect characterized by buccal movement of supporting teeth is also produced.19-22,27,33 As a result, maxillary posterior teeth are buccally displaced by an association of inclination and translation. The literature evinces that buccal tooth movement is associated with the occurrence of bone dehiscences. Engelking and Zachrisson,15 Steiner et al,28 Thilander et al29 and Wennströn et al32 conducted animal investigations and demonstrated that buccal tooth movement with mild forces increases the distance between the cementoenamel junction and the buccal alveolar crest. Wehrbein et al31 reached a similar conclusion when conducting a cadaver study. Buccolingual tooth movement seems to occur through the alveolar bone and not along the bone. It leads to bone dehiscences in the short-term15,28,29,31,32 and to gingival recession in the long-term.1-4 Recent studies conducted with CT have shown apical migration of buccal alveolar crest of posterior teeth after RME is performed in permanent dentition patients.18,25 By means of CT methodology, Garib et al18 assessed a sample of eight female adolescents before RME and after the removal of the expander following a 3-month retention period. The authors concluded that RME induced bone dehiscences on the buccal aspect of supporting teeth (first premolars and first molars), especially in subjects who initially presented thinner buccal bone plate. Rungcharassaeng et al25 found similar results in a sample of thirty consecutive RME patients with a mean age of 13.8 years. Their findings included buccal bone loss in both horizontal and vertical dimensions for all posterior teeth after expansion, and displayed a significant correlation with age, amount (...truncated)