Award Date

5-15-2026

Degree Type

Thesis

Degree Name

Master of Science (MS)

Department

Dental Medicine

First Committee Member

Brian Chrzan

Second Committee Member

Charles Hill

Third Committee Member

Kory Grahl

Fourth Committee Member

Maxim Gakh

Number of Pages

65

Abstract

Background:

Accurate assessment of transverse maxillary dimensions and surrounding bone morphology is critical for safe orthodontic treatment planning. Orthodontic expansion should remain within the biological limits of the alveolar housing and palatal bone to prevent adverse periodontal outcomes, including dehiscence, fenestration, and gingival recession. Standard diagnostic methods, such as dental casts and two-dimensional radiographs, offer limited information about the three-dimensional anatomy that restricts orthodontic tooth movement. Cone-beam computed tomography (CBCT) provides detailed evaluation of skeletal dimensions and cortical bone boundaries. This study aimed to examine the relationships among maxillary transverse width, alveolar housing thickness, and palatal thickness using CBCT imaging.

Methods:

This retrospective cross-sectional study analyzed pretreatment CBCT scans from 65 adult patients at the University of Nevada, Las Vegas School of Dental Medicine orthodontic clinic. Scans were obtained using an iCAT FLX CBCT unit and analyzed with Anatomage Invivo 5 software, following standardized image orientation protocols. Measurements were taken in coronal slices at the levels of the maxillary first molars, second premolars, and first premolars. External maxillary transverse width was defined as the distance between the outer aspects of the buccal cortical plates, and internal transverse width as the distance between the internal palatal cortical boundaries. Alveolar housing thickness was measured as the buccal-to-palatal cortical distance at each tooth level. Palatal thickness was measured lateral to the midpalatal suture from the nasal floor cortex to the palatal cortex. Descriptive statistics and Pearson correlation coefficients were used to evaluate associations among variables. Spearman correlations were performed as a sensitivity analysis. False discovery rate (FDR) correction addressed multiple comparisons. Exploratory linear regression models evaluated predictors of palatal thickness.

Results:

The mean external transverse width was 54.94 mm, and the mean internal transverse width was 29.86 mm. Mean alveolar housing thickness measured 12.74 mm, and mean palatal thickness was 5.45 mm. External transverse width showed strong positive correlations with alveolar housing thickness at all tooth levels (r = 0.69–0.77, FDR-adjusted p < 0.0001). Alveolar housing thickness had modest positive correlations with palatal thickness (r = 0.28–0.34, FDR-adjusted p < 0.05). Internal transverse width did not show significant associations with alveolar housing thickness after FDR correction. Neither external nor internal transverse width consistently predicted palatal thickness. Exploratory regression models identified alveolar housing thickness as the strongest predictor of palatal thickness, but overall model explanatory power was modest, reflecting significant inter-individual variability.

Conclusions:

External maxillary transverse width is strongly associated with alveolar housing thickness and may indicate the size of the alveolar envelope. However, transverse width alone does not reliably predict palatal bone thickness. Palatal morphology and alveolar dimensions vary considerably among adult orthodontic patients. These findings highlight the need for individualized three-dimensional CBCT assessment when evaluating anatomical limits for transverse orthodontic expansion and planning biologically sound treatment.

Controlled Subject

Orthodontics--Practice; Orthodontic appliances; Bones

Disciplines

Dentistry | Medicine and Health Sciences | Osteopathic Medicine and Osteopathy

File Format

PDF

File Size

10500 KB

Degree Grantor

University of Nevada, Las Vegas

Language

English

Rights

IN COPYRIGHT. For more information about this rights statement, please visit http://rightsstatements.org/vocab/InC/1.0/

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