An in vitro study of a combined patient-specific device for safe and accurate insertion of infrazygomatic crest miniscrews.

Objectives: To develop and assess the efficacy of a novel combined patient-specific device (CPSD) for the accurate and safe insertion of infrazygomatic crest miniscrews in orthodontic procedures.

Materials and methods: Twenty-eight miniscrews were placed in the infrazygomatic crest region of 28 cadaver maxillae using the direct manual method (n = 14) or the CPSD (n = 14) based on preset trajectories. The CPSD, designed based on the integration model, included a positioning guide, an insertion guide, and a depth-limiting groove. Deviations in the insertion site, tip location, insertion angle, and biting depth between the preset and real insertion trajectories were calculated to evaluate the accuracy of miniscrew insertion. Classification frequencies of root proximity, sinus penetration depth, and biting depth of the miniscrew after insertion were also calculated to evaluate the safety of miniscrew insertion.

Results: Regarding evaluation of accuracy, significant differences were observed in the deviation values of the insertion site, tip location, insertion angle, and biting depth between the CPSD and freehand groups (P = .001, P < .001, P < .001, P = .039, respectively). Regarding evaluation of safety, a significant difference was observed in the classification frequencies of root proximity between the two groups (P = .016).

Conclusions: Compared with manual insertion, CPSD could be a preferred method for safe and accurate insertion of infrazygomatic crest miniscrews for orthodontists.