Carriere Motion Appliance* Versus In-office Sectional Appliance (CMA)

A Comparison of Class II Correction Using the Carriere Motion Appliance Versus an In-Office Sectional Appliance: Treatment Effects and Efficiency

The "sagittal first" approach to Class II correction in orthodontic treatment involves correcting the antero-posterior (AP) relationship of the maxillary and mandibular dentition prior to the leveling and aligning phase of orthodontic treatment. The Carriere Motion Appliance (CMA) was made to provide sagittal correction prior to orthodontic treatment with minimal secondary tooth movements that are typically seen with Class II correction. The aim in this study is to explore the efficacy and efficiency of Class II molar correction in adolescent patients using the sagittal first approach with either a sectional, in-office fabricated appliance or the CMA, by measuring total treatment duration (in months) as well as comparing dental and skeletal measurements taken from lateral cephalometric radiographs obtained prior to Class II correction (T0) and immediately after removal of the appliance (T1). The investigators will also be comparing secondary molar and canine rotational movements after Class II correction by comparing digital dental casts obtained at T0 and T1.

The investigators will be recruiting 12 to 17-year 11-month old patients with a Class II molar relationship,who are presenting for comprehensive orthodontic treatment at the Postgraduate orthodontic clinic at University at Buffalo School of Dental Medicine. Recruited subjects will be randomized into one of 2 groups. Both groups will be receiving a method of Class II correction using the Sagittal First approach, which means the Class II molar relationship will be corrected prior to the leveling and aligning phase of orthodontic treatment. Subjects will be treated using either the Carriere Motion Appliance (CMA), or a sectional appliance fabricated with materials that are commonly found in orthodontic practice. Both appliances will be used according to the CMA guidelines. After Class II correction and removal of appliance, and prior to the next stage of treatment, an additional digital scan of the mouth and a lateral cephalometric radiograph will be taken. Dental and skeletal measurements from initial cephalometric radiographs and models will be subtracted from the corresponding measurements taken on radiographs and models obtained after Class II correction, and comparisons will be made between the two treatment treatment groups. Efficiency will be determined by number of months until Class II molar and canine correction was obtained, and efficacy will be determined by the skeletal and dental measurements obtained.

Subjects participating in the study and will then be randomly assigned to one of two treatment interventions: Sagittal first approach using the CMA Sagittal first approach using an in-office fabricated custom appliance At the bonding appointment, the appliance will be bonded and AP correction will begin. Both treatment groups will have a button bonded to the mandibular first molars, and Essix retainers with 2 mm thickness will require to be worn at all times for mandibular anchorage during AP correction (only taken out to brush and eat). Both treatment groups will follow the CMA protocol for Class II correction, which consists of wearing Force 1 (1/4, 6 oz) Class II elastics for the first month of treatment, and Force 2 (3/16, 8 oz) Class II elastics for the remainder of Class II correction. Once Class II correction is complete, the appliance will be removed and a lateral cephalometric radiograph and digital model will be obtained

Lateral cephalometric radiographs and digital study models will be de-identified prior to landmarking and obtaining measurements. The appliances will not be present on the patient when these records are obtained and therefore, when taking measurements, the outcomes assessor will not know which intervention the subjects received.

A customized in-office fabricated appliance using the printed digital model of the subject will be used for AP correction. AP correction will be completed following CMA protocol (see model description)

The appropriate length appliance will be placed as directed in the CMA handbook on the maxillary first molar and canine. AP correction will be completed following CMA protocol (see model description)

A 0.022 Slot MBT™ second molar mini tube that has been modified to have a 2 mm length will be placed on the maxillary first molar and a 0.018 slot MBT™ maxillary canine bracket will be placed on the maxillary canine, with a 0.016x0.022 stainless-steel wire spanning from the maxillary first molar to the maxillary canine. A bayonet bend will be placed mesial to the molar tube. A curve will be bent into the wire, so that the wire is able to passively rest on the buccal surface of the maxillary canine. A stainless-steel closed coil will span the molar to canine and lay flush to the mesial portion of the molar tube and the distal portion of the canine bracket. The wire will be cinched mesial to the maxillary canine tie-wing and also 2-3 mm distal to the maxillary first molar to ensure that the molar can rotate during treatment, if needed. A stainless-steel tie will be used to secure the wire into the canine bracket. AP correction will be completed following CMA protocol

A bar spanning from the maxillary first molar to canine with a ball and socket joint at the molar and a canine pad at the canine. A slight bend is present between the molar and canine bracket. The ball and socket is designed to allow the molar to rotate to -15 degrees along it's longitudinal axis. The appliance claims that it allows for Class II correction with minimal secondary tooth movements when used with mandibular anchorage.

From date of Class II correction appliance delivery to date of removal of Class II correction appliance after Class I molar and canine relationship has been established (approximately 120-180 days).

From date of Class II correction appliance delivery to date of removal of Class II correction appliance after Class I molar and canine relationship has been established (approximately 120-180 days).

From date of Class II correction appliance delivery to date of removal of Class II correction appliance after Class I molar and canine relationship has been established (approximately 120-180 days).

From date of Class II correction appliance delivery to date of removal of Class II correction appliance after Class I molar and canine relationship has been established (approximately 120-180 days).

Inclusion Criteria: Males and Females Presenting for comprehensive orthodontic treatment at the Postgraduate orthodontic clinic at the University at Buffalo School of Dental Medicine Unilateral or bilateral ½-cusp to full-cusp Class II molar and canine relationship Growing Patients (~12-17y 11m) Subjects who do not require extractions as part of treatment mechanics Mild to moderate crowding Exclusion Criteria: Patients in mixed dentition Any missing teeth up to and including permanent first molars Bilateral molar relationship of less than ½ cusp Class II prior to appliance cementation