Bone Mapping for Mini-Implant Placement with Various Facial Growth Patterns using Three Dimensional Volumetric Tomography

Abstract

Introduction: Cortical bony morphology is influenced by force applications and stresses and strains produced by functional load of associated muscles of mastication. Also, Facial Growth Pattern is related to muscular function and there is a relationship between cortical bone thickness and facial divergence. Aim: To compare the thickness of cortical bone and interradicular distance in both the jaws among hypo divergent, hyper divergent and normal facial growth pattern. Materials and Methods: Total 45 individuals classified into hyper divergent, hypo divergent and normal facial growth pattern were selected for the study. Three-Dimensional Volumetric Tomography (DVT) scan was conducted for both the jaws and 3-DVT images were generated for each patient by using digital software, curved slicing images with sections of 76 μm thickness were chosen for measurements. The images were oriented in three planes of space so that the inter-radicular space and buccal cortical plates could be measured from the Cemento Enamel Junction (CEJ). One-way ANOVA test was used to analyse the data with statistical significance considered at a p-value lower than 0.05 at 95% confidence interval. Results: The average cortical bone thickness in hypo, hyper and normal facial divergent pattern was 1.16 to 1.5 mm, 0.92 to 1.28 mm and 0.96 to 1.5 mm respectively in maxilla whereas it was 1.48 to 2.82 mm, 1.14 to 2.30 mm and 1.24 to 2.62 mm respectively in mandible. The average inter-radicular space in hypo, hyper and normal divergent facial profile ranged from 1.7 to 4.32 mm,1.62 to 4.06 mm and 1.36 to 3.7 mm respectively in maxilla and 1.66 to 4.5 mm,1.52 to 4.32 mm and 1.86 to 3.4 mm respectively in mandible. Conclusion: Findings of the present study suggests that cortical bone thickness in the maxilla and mandible variably increases from anterior to posterior in different levels and mandibular cortical bone is thicker than maxillary cortical bone in all facial growth pattern individuals.

Keywords

• cortical bone
• facial patterns
• inter-radicular bone thickness
• orthodontics