異なる不正咬合特性が全体的な矯正治療期間に及ぼす影響

To identify pretreatment malocclusion traits that may influence treatment duration and to assess the correlation between these factors and overall treatment duration.

This retrospective study included 1430 patients who completed orthodontic treatment between July 2013 and March 2022. A comprehensive evaluation of patient records was conducted, and data related to the initial malocclusion and its associated traits were extracted, including 13 parameters such as Angle's classification, overjet, overbite, open bite, and crowding.

Severe overjet (>9 mm) and reverse overjet were significantly associated with longer treatment duration. Increased overbite was also associated with longer treatment duration, with deep impinging overbite requiring an additional 6 months compared with an average overbite (P < .001). Bilateral posterior crossbite significantly increased mean treatment duration by 4.76 months (P < .001). Additionally, a midline shift > 3 mm was associated with a 2.3-month increase in mean treatment duration (P = .009).

Severe malocclusion traits including increased overjet, reverse overjet, deep overbite, and open bite were strongly linked to longer treatment duration. Similarly, crowding, crossbites, and midline shifts also contributed to extended treatment duration. The presence of missing or impacted teeth, particularly impacted canines and central incisors, led to significant delays in treatment.