Accuracy of two orthodontic mini-implant templates in the infrazygomatic crest zone: a prospective cohort study

BACKGROUND: In the clinic, most computer-aided design and manufacturing orthodontic mini-implant guides are suitable for the position between the tooth roots, and few templates are designed and used for the infrazygomatic crest zone. In this study, we took into account the structure of the infrazygomatic crest and 3D printing technology, developed two kinds of templates, and evaluated their clinical effects. METHODS: Seventeen patients who accepted 30 mini-implant insertions in the infrazygomatic crest were selected. According to different implantation methods, three groups were divided. In Groups A and B, the mini-implants were positioned with an A-type or B-type template designed by EXOCAD software. In Group C, the mini-implants were inserted by an experienced orthodontist without any guides. We simulate the bucco-palatal, mesio-distal, and vertical head positions in the Segma implant guide software and measure the deviation from the virtual design position of the mini-implant. The linear deviation of the mini-implant tip and cap and the angular deviation of the long axis of the mini-implant in the bucco-palatal direction, mesio-distal direction, and vertical direction were also measured. The results were statistically analysed by SPSS software. RESULTS: The deviations of Group A and Group C’s miniscrew cap in the bucco-palatal direction, Group A and Group B, Group A and Group C’s miniscrew tip in the mesio-distal direction, and Group B and Group C’s miniscrew tip and cap in the vertical direction were statistically significant (P < 0.05). There was a significant difference in the deviations of Group A and Group C’s miniscrew tip and cap in the vertical direction (P < 0.01). CONCLUSIONS: In the vertical direction, the accuracy of implantation with the template is higher than that of the traditional method without the template to avoid piercing the maxillary sinus mucosa in the infrazygomatic crest zone.