[Clinical characteristics and comprehensive treatment of patients with cleidocranial dysplasia]

Objective: To summarize the clinical characteristics of patients with cleidocranial dysplasia (CCD) and analyze their treatment methods. Methods: From January 2000 to December 2020, patients with CCD who completed comprehensive treatment in the Department of Orthodontics and the First Dental Clinic, School and Hospital of Stomatology, China Medical University were retrospectively analyzed. A total of 14 CCD patients [7 males and 7 females, aged (16.1±4.5) years] were collected. There were 153 impacted permanent teeth in this study. In addition to the teeth that needed to be extracted due to special conditions, 147 impacted teeth were pulled into the dentition using closed traction. Patients were divided into adolescent group (≥12 years and<18 years, 10 patients) and adult group (≥18 years, 4 patients). Failure rate of traction was compared between the two groups. Factors affecting the success rate of closed traction such as vertical position of teeth (high, middle and low) and horizontal position of the teeth (palatal, median and buccal) were analyzed. Results: The incidence of maxillary impacted teeth [69.3% (97/140)] was higher than that of mandibular impacted teeth [40% (56/140)]. The difference was statistically significant (χ²=24.22, P<0.001). The supernumerary teeth were mainly located in the premolar area 61.4% (21/44), and most of them were in the palatal region of the permanent teeth 95.5% (42/44). They were generally located at the same height or the occlusal side of the corresponding permanent teeth. The success rate of closed traction was 93.9% (138/147). The success rate in the adolescent group [98.2% (108/110)] was higher than that in the adult group [81.1% (30/37)], and the difference was significant (χ²=14.09, P<0.05). Failure after closed traction of 9 teeth was found totally, including 7 second premolars. The success rate of traction in impacted second premolars at different vertical (χ²=11.44, P<0.05) and horizontal (χ²=9.71, P<0.05) positions in alveolar bone was different significantlly. The success rates of the second premolars were high (15/16), middle (12/13), low (2/7), and lingual palatine (10/17), median (19/19), lip-buccal (0/0), respectively. Conclusions: The closed traction of impacted teeth in patients with CCD was effective, and the age was the main variable affecting the outcome. The success rate of traction in impacted second premolars located in low position vertically or in palatal position was low, which required close observation during treatment.