关键词: 正畸托槽, 数字化间接粘接, 三维配准, 精准度

Abstract: Objective    To compare the accuracy of the digital indirect bonding technique（IDB）with that of the traditional IDB for in vitro orthodontic bracket bonding. Methods    A total of 20 patients scheduled for fixed orthodontic treatment at the Department of Orthodontics，Stomatological Hospital of Xi'an Jiaotong University between September and November 2023 were enrolled. Three dentition plaster models were fabricated for each patient. These models were allocated for use in the experimental and clinical stages of the traditional IDB protocol，as well as the clinical stage of the digital IDB protocol. In the experimental phase of the traditional IDB protocol，brackets were manually positioned and bonded on the plaster models. These were then digitally scanned to create a working model. Using a double-layer transfer tray，the brackets were subsequently transferred and bonded onto the clinical-stage plaster models. Finally，these models were digitally scanned to form the patient model，which was designated as the traditional group. The clinical-stage plaster models for the digital IDB protocol were scanned to obtain digital models，on which the brackets were virtually positioned（creating a digital working model）. Subsequently，using digital light processing（DLP）printing and a double-layer transfer tray，the brackets were fabricated and bonded onto the clinical-stage plaster models. These models were then digitally scanned to create the patient model，which was designated as the digital group. The working model served as the control for three-dimensional registration with the respective patient model. Subsequently，compare and analyze linear deviations（gingival-occlusal，mesial-distal，labial/buccal-lingual/palatal）and angular deviations（rotation，torque，angulation）between the two groups，followed by the calculation of the overall bracket pass rate. Results    A total of 20 working models were included respectively in the digital group and traditional group. Brackets were bonded to the incisors，canines，premolars，and first molars，resulting in 480 brackets per group. Among them, thirteen brackets that debonded during the transfer process were excluded，yielding a final analysis of 473 brackets in the traditional group and 474 in the digital group. The digital group demonstrated significantly smaller deviations in the linear（gingival-occlusal，mesial-distal，labial/buccal-lingual/palatal）and angular（rotation，angulation）measurements，along with a significantly higher overall bracket success rate，compared to the traditional group（all P < 0.05）. No statistically significant differences were observed in the bracket torque deviation or its bracket success rate between the two groups（P > 0.05）. A statistically significant difference between the two groups was observed only in the mesial-distal direction. The digital group exhibited a predominantly mesial offset，with mesially brackets accounting for 72.8%（χ² = 18.342，P < 0.001）. Except for the gingival-occlusal and torque measurements，comparisons of other bracket deviation parameters between the two groups showed statistically significant differences across all tooth positions（all P < 0.05）.  Conclusion    Compared to the traditional technique，the digital IDB protocol demonstrates superior accuracy for in vitro orthodontic bracket bonding and achieves a higher clinically acceptable success rate. However，further improvements are warranted in torque control，individualized tooth positioning，and clinical application.

Key words: orthodontic brackets, digital indirect bonding, three-dimensional registration, accuracy