Sciote, James J.; Godel, Jeffrey H.; Spannhake, Elizabeth; Hardigan, Patrick C. (Temple University. Libraries, 2015)
      Introduction: The purpose of this study was to subclassify the types of facial asymmetries present in a pre-surgical dentofacial deformity patient population to determine the prevalence of each subcategory. Associations between the craniofacial characteristics of each asymmetry and pre-surgical Jaw Pain and Function Questionnaire (JPFQ) scores, diagnosis of temporomandibular disorders (TMD), and posterior facial asymmetry (PFA) as determined by nasal septum deviation were analyzed. In addition, the data will aid in the development of a phenomics database to allow for subsequent genotyping and gene expression evaluation from patient saliva and masseter muscle samples that were obtained at the time of corrective orthognathic surgery. Methods: Pre-surgical posterio-anterior (PA) cephalograms, submentovertex (SMV) and panoramic (PAN) radiographs from 92 pre-surgical dentofacial deformity patients at the Department of Oral and Maxillofacial Surgery, University of Lille, France were collected to evaluate facial asymmetry. PAs were traced and analyzed according to the Grummons Simplified Frontal analysis and Ramal Height analysis (Dolphin Imaging). SMVs were analyzed by the refined clinical system of the Ritucci and Burstone analysis proposed by Arnold et al along with original angular measurements for maxillary, mandibular, and nasal septum deviations (ImageJ). PFA was determined by a nasal septum deviation greater than 15 degrees. Lastly, PANs were evaluated visually for condylar pathologies. A comprehensive diagnostic decision tree for facial asymmetry was formulated based upon the current literature for normal variation of landmarks and the study design. Patient diagnosis via the decision tree was compared to visual examination of the appropriate x-rays to verify accuracy. Using this decision tree, patients were classified into subtypes and prevalence of each was calculated to form a phenomics database for future research on genotyping and gene expression. Associations between the subclassifications, mean pre-surgical JPFQ scores, temporomandibular joint (TMJ) clinical examination results (TMD+ or TMD-), and the diagnosis of posterior facial asymmetry (PFA+ or PFA-) were completed. Results: Sixty-two patients were able to fulfill all radiographic requirements to arrive at a diagnosis. Eighteen patients demonstrated facial asymmetry that fell within normal biological variation while the other 44 were diagnosed as having a form of facial asymmetry – Cranial Base Asymmetry: 11 female, 6 male; Non-Condylar Mandibular Asymmetry: 5 female, 3 male; Hemimandibular Elongation: 2 female, 3 male; Maxillary Asymmetry: 3 female, 1 male; Idiopathic Condylar Resorption: 3 female, 1 male; Atypical Asymmetry: 3 female, 1 male; Hemimandibular Hyperplasia: 1 female, 0 male; and Maxillary Base & Mandibular Body Asymmetry: 0 female, 1 male. JPFQ scores for symmetric patients ((x ) ̅= 5.33) and asymmetric patients (x ̅= 4.57) were non-significant overall, however, differences between gender were noted (female symmetric (x ) ̅= 6.13, male symmetric (x ) ̅= 1.33, female asymmetric (x ) ̅= 5.36, male asymmetric (x ) ̅= 3.19). TMD was diagnosed by pre-surgical TMJ examinations and MRIs. Four symmetric patients (3 female, 1 male) were positively diagnosed with TMD while 14 asymmetric patients (11 female, 1 male) also were diagnosed. PFA was diagnosed when nasal septum deviation was greater than 15 degrees – 25⁰ to ≤35⁰: 9 patients; >35⁰ to ≤45⁰: 3 patients; >45⁰: 1 patient. Twenty patients with a positive PFA were asymmetric while the other 8 symmetric. Twenty-one patients with PFA were female while the other 7 were male. Conclusion: A comprehensive diagnostic decision tree for facial asymmetry classification was formulated and validated. With it, it was found that: Females have increased JPFQ scores and clinical diagnosis of TMD versus males. Asymmetric females have decreased JPFQ scores, but increased prevalence of TMD. Presence of PFA does not appear to be a strong influence on development of facial asymmetry but is significantly linked to the presence of TMD. PFA is present in nearly half of all dentofacial deformity subjects. Mandibular asymmetry is most commonly associated with increased JPFQ scores and presence of TMD. However, Hemimandibular Hyperplasia, a particular and less common form of mandibular asymmetry, never associated with TMD. One form of mandibular and mid-facial asymmetry, Atypical Asymmetry, had a relatively high prevalence of TMD. Future directions for this research include continuation of genotypic description of IGF1 and Nodal biologic pathways to determine how gene expression levels in masseter muscle and patient genotypes differ in the eight subclassifications of craniofacial asymmetry compared to the symmetric population.