UNC School of Dentistry - The University of North Carolina at ...

#35 Candidate Gene Analysis of a Persistent Pain DisorderS. SMITH, M. SIDDIQI, V. MILLER, D. GIBSON, R. ARUNASALAM, P. KASRAVI, G. SLADE, A. NEELY,E. BAIR, W. MAIXNER, and L. DIATCHENKOCenter for Neurosensory DisordersObjective: Although evidence supports a heritable basis for pain conditions such as temperomandibular joint disorders(TMJD) and fibromyalgia, few genetic determinants for persistent pain have been identified. We employed anextensive panel of genes critical for human pain perception to look for associations with TMJD prevalence. Methods:200 Caucasian females with a history of chronic TMJD were recruited as cases at a multidisciplinary pain clinic, withan equal number of corresponding controls. Subjects underwent comprehensive sensory and experimental paintesting, as well as a battery of psychosocial assessments. DNA from donated blood was genotyped using a ParalleleMIP technology microarray chip comprised of 3295 single-nucleotide polymorphisms (SNPs), representing over 300genes known to influence pain pathways. This panel was specifically designed to assay polymorphisms most likely toregulate gene expression and function. Statistical associations between genetic markers and disease phenotypes wereexamined using PLINK software. Allelic and genotypic tests were employed to determine associations betweencandidate genes and disease status, and linear regression was used for quantitative sensory and affective traits.Results: Numerous polymorphic genes were significantly or suggestively implicated in persistent TMJD or itsputative risk factors, including some involved in stress modulation and nociceptive neurotransmission. Associatedodds ratios for common (MAF>0.05) risk alleles for TMJD ranged up to 2.2. Haplotype analysis further revealedmultilocus effects contributing to genetic variability in these traits. The results of this study were then compared withassociations previously revealed in a separate incidence sample of 186 initially disease-free subjects. Several riskgenes identified in the smaller sample, including genes for adrenergic and opioid receptors, were replicated in thisstudy, supporting the likelihood that they are true associations. Conclusions: Genetic variants relevant to painamplification and psychological distress likely contribute to the complex pathology underlying the maintenance ofpersistent pain in TMJD. Using a candidate gene approach, we successfully implicated a number of pain-relevantgenes and pathways in susceptibility to a persistent pain disease. Supported by NIDCR and NINDS grants RO1-DE16558 (LD), UO1-DE017018(WM and LD), NS41670 (WM) and PO1 NS045685 (WM).#36 A comparison of radiographic intraoral techniques on preclinical skill performanceJ.L. BRAME and S.M. MAURIELLODepartment of Dental Ecology:Although beam alignment devices are recommended for intraoral radiographic imaging, the Stabe® is often taught toenhance the understanding of paralleling techniques. No studies have evaluated the effectiveness of this teachingmethod. Objectives: The purpose of this retrospective study was to assess the preclinical performance of dentalhygiene students using two radiographic techniques. Methods: Thirty six first year dental hygiene studentsparticipated in six weeks of learning and practicing intraoral periapical and bitewing projections using the Stabe®receptor-holding device on human skull manikins. Each student completed a competency exam by exposing a half fullseries of radiographs (n=10) on a human skull manikin. Following this instruction and competency with the Stabe®,each student was given three weeks of instruction and practice using the extension cone paralleling (XCP®) receptorholdingdevice. A competency exam was completed by exposing a half full series of radiographs (n=10) on a humanskull manikin using the XCP® holder. For both Stabe® and XCP® competency exams, the students were allotted 50minutes to expose the ten projections, and each student scanned in their own projections. The projection evaluationwas based on errors occurring in packet placement, horizontal angulation, vertical angulation, and cone centering, aswell as diagnostic acceptability. Each set of projections were evaluated by an experienced evaluator. Data wereanalyzed using a two tailed paired t-test. Results: Students performed significantly better (p=0.00007) on theircompetency exams using the Stabe® receptor holding device compared to their scores with the XCP® (means were88.1 and 83.9, respectively). Conclusion: Based on these retrospective findings, use of the Stabe® prior to the XCP®did not enhance performance with the XCP holder. Findings may have been influenced due to the sequence ofteaching the techniques and/or the time spent teaching each method; a prospective randomized trial should beconducted.26