<?xml version='1.0' encoding='UTF-8'?><xml><records><record><source-app name="HighWire" version="7.x">Drupal-HighWire</source-app><ref-type name="Journal Article">17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Lambert, Cynthia A.</style></author><author><style face="normal" font="default" size="100%">Sanders, Anne</style></author><author><style face="normal" font="default" size="100%">Wilder, Rebecca S.</style></author><author><style face="normal" font="default" size="100%">Slade, Gary D.</style></author><author><style face="normal" font="default" size="100%">Van Uum, Stan</style></author><author><style face="normal" font="default" size="100%">Russell, Evan</style></author><author><style face="normal" font="default" size="100%">Koren, Gideon</style></author><author><style face="normal" font="default" size="100%">Maixner, William</style></author></authors><secondary-authors></secondary-authors></contributors><titles><title><style face="normal" font="default" size="100%">Chronic HPA Axis Response to Stress in Temporomandibular Disorder</style></title><secondary-title><style face="normal" font="default" size="100%">American Dental Hygienists Association</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">2013-04-01 00:00:00</style></date></pub-dates></dates><pages><style  face="normal" font="default" size="100%">73-81</style></pages><volume><style face="normal" font="default" size="100%">87</style></volume><issue><style face="normal" font="default" size="100%">2</style></issue><abstract><style  face="normal" font="default" size="100%">Purpose: Perceived stress is associated with temporomandibular disorder (TMD), but whether cortisol levels are elevated in individuals with TMD is unknown. We hypothesized that cortisol concentration, a biomarker of hypothalamic-pituitary-adrenal (HPA) axis function, was elevated in TMD cases relative to controls, and that perceived stress was positively correlated with cortisol concentration. Methods: In this case control study, TMD case status was determined by examiners using TMD Research Diagnostic Criteria. Participants (n=116) aged 18 to 59 years were recruited from within a 50 mile radius of the University of North Carolina at Chapel Hill. Following examination, cases (n=45) and controls (n=71) completed the 14-item Perceived Stress Scale using a reference interval of the past 3 months. Approximately 100 strands of hair were cut from the posterior vertex segment of their scalp. The 3 centimeters of hair most proximal to the scalp was analyzed with a commercially available salivary cortisol enzyme immunoassay adapted for hair cortisol. This length corresponds to the last 3 months of systemic HPA axis activity. Results: TMD cases perceived higher stress than controls (p=0.001). However, hair cortisol concentration was lower in TMD cases than controls (p&lt;0.001). The correlation coefficient revealed a weak negative relationship (r=-0.188) between perceived stress and hair cortisol concentration (p=0.044). In analysis stratified by case status, the relationship of perceived stress and hair cortisol concentration was non-significant for cases (p=0.169) and controls (p=0.498). Conclusion: Despite greater perceived stress, TMD cases had lower hair cortisol concentrations than controls and the 2 measures of stress were weakly and negatively correlated.</style></abstract></record></records></xml>