Unilateral and bilateral corticotomies for correction of maxillary transverse discrepancies

Surgically-assisted rapid maxillary expansion in adults has been proved effective in overcoming the strong resistance of the maxillary complex after growth is completed, particularly after the second decade of life. The aim of this study was to describe the dental and the skeletal expansion and relapse, as well as the amount of tipping of the two maxillary bones and first permanent molars, during a rapid maxillary expansion procedure combined with unilateral and bilateral corticotomies. The sample consisted of four adult patients, two presenting with bilateral and two with unilateral cross-bite. Records were taken before and after rapid maxillary expansion, at the end of retention and at least 12 months post-retention. In the cases of bilateral cross-bite the same amount of skeletal expansion was observed on both sides. The angular changes measured at the upper first molars indicated important tipping on both sides, which tended to relapse moderately during the retention and post-retention period. Following unilateral surgery, the operated side showed more than twice the amount of skeletal expansion than the non-operated side. The angular changes presented twice as much tipping and relapse on the operated side. The results of this study demonstrate that unilateral cross-bites in adults can be corrected with unilateral corticotomy and rapid maxillary expansion using the contralateral non-operated side as anchorage. Stability appeared satisfactory in all case

Skeletal and dental changes following surgically assisted rapid palatal expansion

The purpose of this study was to analyse the changes produced by surgically assisted rapid palatal expansion (SARPE) longitudinally on 14 patients aged between 18 and 41 years. A pre-fabricated Hyrax appliance was cemented prior to the surgical intervention, which consisted of a maxillary buccal corticotomy with pterygoid separation. Models and postero-anterior (PA) headfilms were taken before expansion (T1), at the end of expansion (T2), at the end of retention (T3) and at least 1 year post-surgery (T4). Overall expansion and relapse were measured directly on the casts. Transverse distances increased more at the first molars (8.7 mm) and premolars (8.1 and 8.3 mm) than in the canine (5.2 mm) and second molar (5.5 mm) region. Minimal relapse occurred during the retention phase. The arch width decreased more during the post-retention period, with more pronounced reduction at the teeth used as anchorage during the expansion procedure (−2.0 mm for the first premolars and −2.6 mm for the first molars). The mean total dental relapse was 28 per cent. PA radiographic analysis for angular changes showed 9.6 degrees of lateral tipping per side during expansion. One-third of this movement relapsed during the retention period (−3.3 degrees) and this trend (−6.0 degrees) continued during the post-retention phase to reach practically the original value at T1. Skeletal changes monitored on the PA headfilms were minimal with great individual variation. The mean expansion measured in the proximity of the osteotomy site was only 1.3 mm. From this amount, 0.4 mm was lost during the retention and post-retention periods. Based on these findings, it appears that maxillary skeletal expansion by SARPE is mainly a lateral rotation of the two maxillary halves with only minimal horizontal translatio

Avaliação cefalométrica das alterações dentoesqueléticas de jovens com má oclusão de Classe II dentária tratados com distalizadores Jones jig Cephalometric evaluation of dentoskeletal changes in Class II young patients treated with Jones jig appliances

OBJETIVO: esta pesquisa objetivou avaliar cefalometricamente as alterações dentoesqueléticas de jovens com Classe II dentária tratados com o distalizador Jones jig. METODOLOGIA: foram avaliados 30 pacientes, sendo 15 de cada gênero, com média de idades iniciais de 13,63 anos; brasileiros, naturais da cidade de Bauru/SP, caracterizados por má oclusão de Classe II, 1ª e 2ª divisões de Angle sem comprometimento esquelético. Os jovens foram tratados com aparelho Jones jig a fim de distalizar os molares superiores a uma relação molar de "super Classe I"; sendo que esse dispositivo permaneceu, em média, por 0,55 anos. Ao final da sobrecorreção, os molares distalizados receberam um botão de Nance e, como ancoragem extrabucal, o aparelho extrabucal (AEB) com tração média-alta, com o intuito de verticalizar e corrigir a angulação radicular dos molares distalizados. Foram realizadas telerradiografias em normal lateral inicial (T1) e pós-distalização (T2). As medidas cefalométricas foram submetidas ao teste t dependente de Student para avaliar as alterações de T1 para T2. RESULTADOS: com base nos resultados obtidos e a partir da metodologia empregada, observou-se alterações dentárias significativas, como a movimentação distal linear e angular, assim como a intrusão dos segundos e primeiros molares superiores no sentido vertical. Também se confirmou efeitos indesejáveis, como a perda de ancoragem refletida em mesialização, extrusão e angulação mesial dos segundos pré-molares, a protrusão dos incisivos superiores e o aumento do trespasse vertical e horizontal. Pode-se confirmar que certas movimentações dentárias promovem significativas alterações esqueléticas de estruturas localizadas à distância, ou seja, observou-se extrusão significativa dos segundos pré-molares superiores, o que resultou em rotação mandibular, aumento significativo da altura facial anteroinferior e protrusão do lábio inferior. CONCLUSÃO: pode-se concluir que o distalizador Jones jig promove, basicamente, alterações dentárias.<br>AIM: This research aimed to evaluate dentoskeletal changes in Class II young patients treated with Jones jig appliances. METHODS: Thirty patients were evaluated in this study, 15 males and 15 females, Brazilian, natural from Bauru city with average age of 13.63 years. They were characterized by Angle Class II division I and II malocclusions without skeletal compromising. The patients were treated with the Jones jig appliance. The treatment lasted for 0.55 years. It's purpose was the distalization of the first maxillary molars to normal molar relationship. After this movement, the maxillary molars were anchored with Nance button, and extraoral headgear was used to correct the tipping of the distalized molars. Lateral cephalograms were obtained at two observation stages: before treatment, and after distalization, to evaluate dental and skeletal changes induced by the Jones jig appliance. Cephalometric values were submitted to dependent sample Student t test to identify changes between T1 and T2. RESULTS: Based on the obtained results and the applied methodology, significant dental changes were observed, such as distalization, distal tipping, and intrusion of first maxillary molars. Anchorage loss was also observed, characterized by significant extrusion; mesial movement and tipping of the maxillary second premolar; protrusion of the maxillary incisors; and increase of overbite and overjet. CONCLUSIONS: It can be concluded that some dental movements promote significant skeletal changes, such as significant extrusion of the second maxillary premolars resulted in clockwise mandibular rotation, increase of the lower anterior face height, and protrusion of the lower lip. Then, it was concluded that the Jones jig appliance promotes basically dental changes