Semester

Spring

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Orthodontics

Committee Chair

Peter Ngan

Committee Member

Khaled Alsharif

Committee Member

Guoqiang Guan

Abstract

Abstract

The Impact of Normal Growth on the AP Relationships of the Jaws and Incisors to the Forehead: A Serial Cephalometric Analysis of Untreated Individuals

Adam Rudmann D.D.S. M.S.

Background and Objectives

Growth of the craniofacial complex is a critical factor to consider when treatment planning an orthodontic case. The ability to predict how the forehead and jaws will change over time depends on the ability to find predictable landmarks either radiographically or clinically, and use them to gauge the relative growth of various facial structures. This data can then be integrated with other diagnostic information such as occlusion and facial esthetics to arrive at an appropriate diagnosis and treatment plan. The purpose of this investigation was to evaluate the impact on the facial profile of normal jaw growth after the complete eruption of the permanent incisors in untreated individuals using soft tissue glabella as the primary landmark.

Materials and Methods

Serial lateral cephalograms of 74 untreated growing individuals (3 female, 39 male) from the Oregon, Iowa, and Bolton-Brush Growth Studies were obtained from the AAOF Legacy Collection. Cephalometric superimpositions were used to assess AP jaw and incisor displacement during the growth period using a novel method of superimposition centered on the external surface of the forehead (glabella).

Results

The mean age of the sample at the beginning of the observation period (T1) was 10.1 years and 17.7 at the end of the observation period (T2). The AP position of the maxillary incisor showed an average of 0.34mm anterior displacement in relation to Glabella in untreated subjects between T1 and T2 with no significant difference between males or females. The AP position of the mandibular incisor showed an average of 0.96mm anterior displacement in relation to Glabella in untreated subjects between T1 and T2 with a significant difference between male and female subjects (p=.04); male subjects had a greater lower incisor displacement (1.35mm vs. 0.57mm) relative to Glabella than female subjects. No other statistically significant differences were found in means of other measurements between sexes.

Conclusion

Based on the findings of this research, the null hypothesis of: After the complete eruption of the permanent incisor teeth, and in the absence of orthodontic treatment, growth anomalies, or other significant environmental influences, normal growth will significantly affect the AP positions of the jaws and incisors relative to the external surface of the forehead, can be rejected. After the complete eruption of the permanent incisor teeth, and in the absence of orthodontic treatment, growth anomalies, or other significant environmental influences, normal growth will not significantly affect the AP positions of the jaws and incisors relative to the external surface of the forehead (glabella).

Embargo Reason

Publication Pending

Available for download on Friday, April 04, 2025

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