The impact of force magnitude on the first and second maxillary molars in cervical headgear therapy

Abstract

Summary Aim To study the effect of force magnitude on the maxillary first and second molars in cervical headgear (CHG) therapy. Material and methods In this controlled clinical trial, patients (n = 40) were treated with CHG with a light (L, 300 g, n = 22) or a heavy force (H, 500 g, n = 18) magnitude. The subjects were asked to wear CHG for 10 hours a day for 10 months. The outer bow of the CHG facebow was lifted up for 10–20 degrees and the inner bow was expanded 3–4 mm. Adherence to instructions and force magnitude were monitored using an electronic module (Smartgear, Swissorthodontics, Switzerland). Panoramic and lateral radiographs before (T1) and after treatment (T2) were analysed using a Romexis Cephalometric module (Planmeca, Finland) focussing on the angular, sagittal, and vertical positions of the permanent first and second molars. Results According to the cephalometric analysis of the maxillary first and second molars, distal tipping occurred during T1–T2 in the H group (P = 0.010 and 0.000, respectively), and the change was greater in the H group compared to the L group (P = 0.045 and 0.019, respectively). Based on the panoramic analysis, tipping occurred in the distal direction during therapy in the H group in the second molars compared to the midline or condylar line (P = 0.001 and 0.001; P = 0.008 and 0.003 on the right and left, respectively). Conclusion With heavy force magnitude, the maxillary first and second molars can tilt more easily in the distal direction even if the CHG was used less. Distal tipping of the molar can be considered to be a side effect of CHG therapy.

Effects of force magnitude on dental arches in cervical headgear therapy

“…The maxillary molar movement in the distal direction is not all bodily movement, but tilting can also occur during HG therapy ( 23 , 28 , 29 , 50 ). In our previous study, maxillary first and second molars were found have tipped more distally with heavy force than with light force ( 50 ).…”

“…The maxillary molar movement in the distal direction is not all bodily movement, but tilting can also occur during HG therapy ( 23 , 28 , 29 , 50 ). In our previous study, maxillary first and second molars were found have tipped more distally with heavy force than with light force ( 50 ). The follow-up period in this study was rather short, 10 months, and thus not all patients had early permanent dentition by the end of the study.…”

“…The subjects and methods have been presented in our previous studies ( 43 , 49 , 50 ) but for clarification they are also presented here. The study subjects were recruited from a pool of children appropriate for the orthodontic treatment at the Health Care Center of Turku, in Turku, Finland.…”

Tratamiento temprano ortodóncico/ortopédico en pacientes con anomalías sagitales de clase II. Una revision.

“…Talvitie et al . 21 mencionan que la aplicación de fuerzas moderada (500 g) produce una mayor inclinación distal de los primeros y segundos molares en el tratamiento con arnés cervical.…”

Manejo ortodóntico interceptivo de los problemas oclusales resultantes de segundos molares primarios anquilosados. Reporte de caso

“…Algunos estudios reportan que el uso del arco extraoral es un dispositivo eficaz cuando se utiliza para la distalización de los primeros molares superiores para lograr una relación molar de clase I o para recuperar el espacio perdido por la pérdida prematura de piezas deciduas, no obstante, es común evidenciar que este movimiento distal es acompañado por una inclinación distal de la corona, por ello algunos autores recomiendan utilizar 300 gramos [40][41][42] .…”