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Quantitative evaluation of cortical bone thickness with computed tomographic scanning for orthodontic implants
Toru Deguchi1, Miho Nasu, Kaoru Murakami
1Department of Orthodontics and Dentofacial Orthopedics, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Summary
Miniscrew placement for orthodontic anchorage is safest mesial or distal to the first molar. Optimal miniscrew dimensions are under 1.5mm diameter and 6-8mm length for safe bone anchorage.
Area of Science:
- Orthodontics
- Dental Implantology
- Oral and Maxillofacial Surgery
Background:
- Cortical bone thickness and root proximity are critical for successful orthodontic miniscrew anchorage.
- Quantitative data on these parameters in the maxilla and mandible are essential for safe implant placement.
Purpose of the Study:
- To quantitatively evaluate cortical bone thickness in the maxilla and mandible.
- To measure distances from intercortical bone to root surfaces and between tooth roots.
- To determine optimal miniscrew dimensions (length and diameter) for orthodontic anchorage.
Main Methods:
- Reconstruction of 3D computed tomographic images from 10 patients.
- Measurement of cortical bone thickness at various buccal and lingual sites and angles.
- Assessment of intercortical bone to root surface distances and root proximity.
Main Results:
- Mandibular bone was significantly thicker than maxillary bone, particularly distal to the second molar.
- Cortical bone thickness varied with location, angle, and level (anterior nasal spine vs. Point A).
- Greater distances from bone to root surfaces were found lingually and distally to molars.
Conclusions:
- Mesial or distal to the first molar appears to be the safest location for miniscrew placement.
- Miniscrews with a diameter less than approximately 1.5 mm and length of 6-8 mm are recommended.
- These findings provide crucial data for optimizing miniscrew anchorage in orthodontic treatment.