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A prospective randomized controlled clinical study on treatment duration and early tooth movement in surgical exposure and orthodontic traction of impacted maxillary canines with intentional luxation (Intentional Luxation - Canine Exposure and Traction)

A prospective randomized controlled study of intentional luxation in the treatment of impacted maxillary canines (A prospective randomized controlled clinical study on treatment duration and early tooth movement in surgical exposure and orthodontic traction of impacted maxillary canines with intentional luxation)

Nishiguchi Yusuke

Second Department of Oral and Maxillofacial Surgery, Osaka Dental University

1-5-17 Otemae, Chuo-ku, Osaka, Osaka, Japan

nishiguchi-y@cc.osaka-dent.ac.jp

Nishiguchi Yusuke

Second Department of Oral and Maxillofacial Surgery, Osaka Dental University

1-5-17 Otemae, Chuo-ku, Osaka, Osaka, Japan

+81-6-6910-1076

nishiguchi-y@cc.osaka-dent.ac.jp

Recruiting

May. 06, 2026

Interventional

randomized controlled trial

open(masking not used)

active control

parallel assignment

treatment purpose

Patients aged 8 to 12 years who were diagnosed with unilateral or bilateral impacted maxillary canines at the orthodontic department of our institution.
Cases in which the impacted maxillary canine is located labial to the alveolar crest of the dental arch on CBCT.
Cases in which both preoperative and postoperative panoramic radiographs and CBCT images can be obtained.
Patients for whom written informed consent for participation in the study, including orthodontic treatment, has been obtained.
Cases in which the crown of the impacted canine is located in Sector 2 or 3 according to the Ericson and Kurol classification.
Cases in which the angle between the long axis of the canine and the occlusal plane is 90 degrees or less on panoramic radiographs, without severe inversion or horizontal impaction.
Cases in which the cusp tip of the maxillary canine is located between the cementoenamel junction of the ipsilateral lateral incisor and the nasal floor on panoramic radiographs, without marked low positioning.
Cases without odontogenic tumors, for example odontoma, or cystic lesions requiring additional surgical intervention on preoperative CBCT.
Cases in which there is no severe root resorption of adjacent teeth, and the operator judges that both conventional surgical exposure and exposure with intentional luxation can be performed with comparable safety.

Cases with odontogenic tumors (e.g., odontoma) or cystic lesions requiring additional surgical intervention.
Cases in which severe root resorption or ankylosis is suspected based on preoperative imaging.
Cases in which surgical treatment is considered inappropriate due to systemic conditions.
Cases in which written informed consent for participation in the study cannot be obtained.
Cases in which surgical exposure and orthodontic traction have already been initiated.
Cases deemed ineligible for randomization, or cases in which the operator determines that one of the treatment methods should be strongly recommended based on clinical judgment; such cases will be excluded from the randomized comparison and managed as part of routine clinical care.

Both

Impacted maxillary canines

After surgical exposure of the impacted canine, the spatial relationship with adjacent tooth roots and the direction of traction are evaluated based on CBCT findings. After removal of the bone surrounding the crown, controlled partial luxation is performed using an elevator to provide approximately 1 to 2 mm of mobility along the long axis of the canine. Successful luxation is determined by increased mobility and a corresponding rise in the Periotest value, with a reference range of PT 20 to 29 indicating clinically observable mobility. The procedure is immediately discontinued if signs such as a cracking sound, abnormal mobility, or severe pain are observed. A metal button with a ligature is then bonded at a position that allows traction in a direction away from adjacent tooth roots. Intraoral scanning is performed before and after luxation to record positional changes. Orthodontic traction is initiated 7 to 14 days after surgery using standardized light continuous force. Postoperative management is performed in the same manner as in the control group, with careful attention to avoiding pulp damage.

Impacted maxillary canine

Intentional luxation, impacted canine, surgical exposure, orthodontic traction, randomized controlled trial

D000077193

D013829

Primary outcomes are the treatment duration, defined as (1) the time from initiation of orthodontic traction to eruption of the canine crown into the oral cavity, and (2) the time required for complete alignment of the canine into the dental arch.

Early tooth movement at 4 weeks postoperatively, measured as the displacement of the canine crown.
Direction of tooth movement assessed by three-dimensional vector analysis relative to adjacent tooth roots.
Root resorption of the canine and adjacent teeth, evaluated by changes in the distance from the cemento-enamel junction to the root apex on CBCT.
Angular changes of the canine long axis relative to the occlusal plane on panoramic radiographs.
Intraoperative parameters, including operation time and intraoperative complications.
Tooth mobility assessed using Periotest values and quantitative positional changes measured by intraoral scanning in the intervention group.
Postoperative pain assessed using a visual analog scale (VAS) from postoperative day 1 to day 14, along with epithelialization and presence of postoperative infection.
Incidence of adverse events throughout the treatment period, including pulp necrosis and severe root resorption.

+81-669101076

Mar. 30, 2026

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