Effect of Conventional Versus Passive Self-Ligating Vestibular Appliances on Torque, Tip and Transverse Dental Changes in Patients Affected by Class I Malocclusion: A Retrospective Study

Abstract

Objective: To evaluate the effects of passive self-ligating appliances (PSLAs) and conventional ligating appliances (CLAs) during orthodontic treatment regarding torque, tip, and transversal dental changes. Material and Methods: Dental parameters were digitally acquired from pre- and post-treatment models of each subject belonging to two groups of patients treated with PSLAs (23 patients; 11 females and 12 males with a mean age of 14.2 ± 1.6 years) and CLAs (18 patients; 10 females and 8 males with a mean age of 14.3 ± 1.9 years), respectively. All subjects had Class I or slight Class II malocclusion (≤ 2mm), permanent dentition and no previous orthodontic treatment. After normality of data was assumed, a paired sample t-test rejected any side differences at T0 and, therefore, the data were grouped by tooth group. Statistical analyses were performed using a linear mixed-effect framework, assuming the appliance, time, and interactions as fixed effects and the tooth type as random effects. Finally, post-hoc effect analysis was used to contrast modeled marginal effects (p<0.05). Results: For both appliances, there is a general increase of both torque and transverse values at T1, especially for PSLAs. Tip shows a general reduction in the lateral sectors for both appliances is registered. The only significant statistical difference referred to appliances’ efficacy is located to mandibular intermolar width. Conclusion: Both appliances have an expansive potential for both torque and transverse dental changes. No evident differences are detectable between appliances except for the rate of the mandibular intermolar width increase.

Keywords

• Orthodontics
• Malocclusion, Angle Class I
• Torsion, Mechanical
• Orthodontic Brackets