Comparative Evaluation of Safe Zones in Interradicular Areas of Maxilla for Placement of Mini Orthodontic Implants in Different Vertical Facial Heights

Abstract

Background: The present study aimed to generate a high-resolution anatomical map of the buccal alveolar bone in the right maxillary arch to establish evidence-based guidelines for secure orthodontic miniscrew insertion, with a focused analysis of the interradicular zone between the second premolar and first molar. Cone-beam computed tomography volumes acquired from 90 maxillae using the Carestream 9600 system were processed and analyzed with dedicated Carestream imaging software. Within the targeted interradicular space on the right side, mesiodistal width and buccopalatal bone thickness were quantified at vertical levels of 2, 5, 8, and 11 mm apical to the alveolar crest. The data demonstrated substantial morphological variation across different vertical planes within this specific site, underscoring the necessity for level-specific surgical considerations. These anatomical insights inform a series of practical clinical recommendations for mini screw placement in the right posterior maxilla, encompassing optimal implant dimensions, insertion angulation, and site selection to enhance primary stability while mitigating the risk of root injury or cortical plate perforation.

Objectives: To determine safe zones in interradicular bone region in maxilla in patients with different vertical facial dimension& to determine appropriate sites and angles for insertion of the orthodontic mini-implant in the interradicular region of maxillary arch.

Materials and Methods: This retrospective CBCT-based study analysed images obtained from individuals categorized according to facial growth patterns. Measurements of interradicular distance and the distance from the buccal cortical bone surface to the narrowest interradicular space were recorded at multiple vertical levels from the cemento-enamel junction in the interdental region between the maxillary second premolar and 1st molars. Statistical analysis was performed to evaluate variations among different vertical levels and facial growth patterns.

Results: The mesiodistal interradicular width and buccopalatal bone thickness in the maxillary posterior region showed no significant variation across different vertical facial height groups, with the second premolar–first molar (6-5) region at 5–8 mm from the alveolar crest consistently providing the most favourable dimensions for safe mini-implant placement.

Conclusion: The mesiodistal interradicular width and buccopalatal bone thickness in the maxillary posterior region do not differ significantly across vertical facial height patterns, indicating that established safe zones are universally applicable irrespective of facial morphology. The second premolar–first molar (6-5) region at 5–8 mm from the alveolar crest consistently provides the most favourable dimensions for safe mini-implant placement, making site selection based on interradicular location the critical determinant rather than vertical facial height.