To Örebro University

The maxillary permanent canine usually erupts in the mouth between the ages of 11 and 12 years. Sometimes the canines are displaced toward the palatal side of the dental arch and eruption is disturbed. Palatally displaced canines (PDCs) are a frequent dental anomaly, present in 2% of the young population. If untreated, there is risk of damage to the roots of the adjacent teeth and potential tooth loss. Thus, early interceptive treatment with extraction of the deciduous canine should be undertaken, with the aim to improve the PDC eruption path. If the eruption path does not improve within about a year, surgical exposure and orthodontic treatment is indicated.

The two different main techniques of surgical exposure in PDCs are the open and the closed techniques. Retrospective studies of the exposure techniques have shown differences in outcomes, which high-lights the need for evidence-based research.

The overall aim of this thesis was to compare outcomes of treatment duration, complications and side effects, patients’ perceptions and health economic aspects of the two surgical techniques, in PDCs. Moreover, a comparison of PDC position between the two radiographic methods commonly used in PDC cases; panoramic radiograph and CBCT, aimed to evaluate agreement between the actual measures. 

This thesis was based on a multicentre randomised controlled trial with two parallel groups, including 120 consecutive patients, aged 9 to 16 years, who were randomly allocated to open or closed surgical exposure. 

The following conclusions were drawn:

The agreement of PDC mesiodistal position was fair (weighted kappa 0.36 (95%CI0.24–0.49) and the mean difference in angle to midline was almost 7˚ (95%CI 5.9˚–7.9˚) higher in panoramic radiographs compared with CBCT. Surgery time, treatment time, root resorption or periodontal measures showed no clinically significant differences between the exposure groups. The open group reported higher pain intensity up to one week post surgery. A higher proportion of bilateral open group cases experienced complications, and weremore frequently wakened at night post surgery. The closed group reported higher pain and discomfort during the orthodontic traction. All PDCs were successfully aligned in the dental arch. A cost-minimization analysis showed no differences in healthcare or societal costs.