Treatment Adherence With Twin-Blocks for Correction of Class II Malocclusion

Treatment Adherence With Twin-Blocks for Correction of Class II Malocclusion - a Randomized Controlled Trial on Two Check-up Prescriptions

To compare the effect of two control intervals (once every 4th week or once every 6th week) on the wear time of a Twin Block removable appliance.

If the patient fulfill the inclusion criteria, they will be asked to participate in the study. After being informed about the study and the planned treatment, participants and their guardians will give their written consent to participate in the study. Therafter they will be consecutively randomized into one of two groups with different control intervals, Group 1 (every 4th week) and Group 2 (every 6th week). They will recieve a clinical and radiological examination and then start treatment with a Twin Block appliance. The Twin Block appliance will be fitted with a digital timer module to measure the wear time of the appliance objectively.

This group was controlled every 6th week, in accordance with what is deemed to be "golden standard" for treatment with a Twin Block orthodontic appliance.

This group was controlled every 4th week, testing if a more frequent control interval would increase compliance with a Twin block orthodontic appliance.

Twin Block orthodontic appliance for treating patients with Angle class II molar relationship and a large horizontal overjet, often in combination with an incomplete lip closure

Wear time of the Twin Block appliance, compared between participants randomized into two groups with different check up intervals

To measure if the wear time of the Twin Block appliance would increase if the control interval increased from once every 6th week to once every 4th week. The wear time was registered using the TheraMon system, and was measured in hours per day.

Change in overjet, compared between participants randomized into two groups with different check up intervals

To see if change in overjet would differ between or within the groups before and after treatment was finished. Horizontal overjet was measured in millimetres on study casts before and after treatment was finished.

Change in overbite, compared between participants randomized into two groups with different check up intervals

To see if change in overbite would differ between or within the groups before and after treatment. Overbite was measured in millimetres on study casts taken before and after treatment.

Change in molar relationship, compared between participants randomized into two groups with different check up intervals

To see how molar relationship would be differ between or within the two groups before and after treatment, measured in Angle classification on study casts before and after treatment completion.

Inclusion Criteria: Healthy patients (ASA 1 and 2) Overjet of 6 mm or more Incomplete lip closure Exclusion Criteria: Severe chronic conditions such as asthma or allergies Neuroopsychiatric disorders Craniofacial syndromes Previous orthodontic treatment

Frilund E, Sonesson M, Magnusson A. Patient compliance with Twin Block appliance during treatment of Class II malocclusion: a randomized controlled trial on two check-up prescriptions. Eur J Orthod. 2023 Mar 31;45(2):142-149. doi: 10.1093/ejo/cjac046.