Objectives

To assess the infrazygomatic crest (IZC) and palatal bone width, height, and angulation in patients with different vertical facial growth types as potential miniscrew insertion sites.

Materials and Methods

In this retrospective cone-beam computed tomography study, 162 subjects (81 males and 81 females, mean age 16.05 ± 0.65 years) were included. They were divided into three groups (hypodivergent, normodivergent, and hyperdivergent) based on the Frankfort mandibular plane angle. Ten buccal bone measurements were made at two different coronal sections: maxillary first molar mesiobuccal and distobuccal roots (bilaterally). Six palatal bone measurements were made on a sagittal section at the maxillary central incisors (bilaterally). A total of 32 measurements per subject were considered in the study.

Results

No significant difference was observed for the IZC (width and angle) at the maxillary first molar mesiobuccal root. A comparison of normodivergent and hyperdivergent groups for buccal width at the distobuccal root of the first molar showed significant differences. Palatal bone thickness at the level of 2 mm distal to the apex of the central incisor was significantly higher for the hyperdivergent group (10.43 mm) compared with the normodivergent (7.58 mm) and hypodivergent groups (7.83 mm).

Conclusions

Hyperdivergent subjects tend to present a longer and deeper IZC and increased palatal bone thickness compared with other groups. The recommended insertion angle for the IZC mini-implant at 3 mm from the alveolar crest should be between 75.5° and 77°.

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Author notes

a

Private Practice, Macon, GA, USA.

b

Private Practice, Windsor, Canada.

c

Private Practice, Charleston, SC, USA.

d

Assistant Professor, Department of Bioinformatics and Biostatistics, University of Louisville, Louisville, KY, USA.

e

Clinical Instructor, Department of Orthodontics, University of Louisville, Louisville, KY, USA.

f

Professor and Chair, Department of Orthodontics, University of Louisville, Louisville, KY, USA.

g

Assistant Professor, Department of Orthodontics, University of Louisville, Louisville, KY, USA.

h

Private Practice, Calgary, Canada.