Influence of different stool types on muscle activity and lumbar posture among dentists during a simulated dental screening task

Whereas in the past dental stools typically facilitated a 90° hip angle, a number of currently available alternative designs allow for a more extended hip posture. The present study investigated the influence of different stool types on muscle activity and lumbar posture. Twenty five participants completed a simulated dental procedure on a standard stool, a saddle and the Ghopec. The latter stool comprises a seat pan consisting of a horizontal rear part for the pelvis and an inclinable sloping down front part for the upper legs, with a vertically and horizontally adjustable back rest. Lumbar posture was most close to neutral on the Ghopec, whereas sitting on a standard/saddle stool resulted in more flexed/extended postures respectively. Sitting with a 90° angle (standard stool) resulted in higher activation of back muscles while sitting with a 125° angle (saddle and Ghopec) activated abdominal muscles more, although less in the presence of a backrest (Ghopec). To maintain neutral posture during dental screening, the Ghopec is considered the most suitable design for the tasks undertaken

Lack of evidence for central sensitization in idiopathic, non-traumatic neck pain : a systematic review

Background: Chronic neck pain is a common problem with a poorly understood pathophysiology. Often no underlying structural pathology can be found and radiological imaging findings are more related to age than to a patient's symptoms. Besides its common occurrence, chronic idiopathic neck pain is also very disabling with almost 50% of all neck pain patients showing moderate disability at long-term follow-up. Central sensitization (CS) is defined as "an amplification of neural signaling within the central nervous system that elicits pain hypersensitivity," "increased responsiveness of nociceptive neurons in the central nervous system to their normal or subthreshold afferent input," or "an augmentation of responsiveness of central neurons to input from unimodal and polymodal receptors." There is increasing evidence for involvement of CS in many chronic pain conditions. Within the area of chronic idiopathic neck pain, there is consistent evidence for the presence and clinical importance of CS in patients with traumatic neck pain, or whiplash-associated disorders. However, the majority of chronic idiopathic neck pain patients are unrelated to a traumatic injury, and hence are termed chronic idiopathic non-traumatic neck pain. When comparing whiplash with idiopathic non-traumatic neck pain, indications for different underlying mechanisms are found. Objective: The goal of this article was to review the existing scientific literature on the role of CS in patients with chronic idiopathic non-traumatic neck pain. Study Design: Systematic review. Setting: All selected studies were case control studies. Methods: A systematic search of existing, relevant literature was performed via the electronic databases Medline, Embase, Web of Science, Cinahl, PubMed, and Google Scholar. All titles and abstracts were checked to identify relevant articles. An article was considered eligible if it met following inclusion criteria: (1) participants had to be human adults (> 18 years) diagnosed with idiopathic non-traumatic chronic (present for at least 3 months) neck pain; (2) papers had to report outcomes related to CS; and (3) articles had to be full-text reports or original research (no abstracts, case-reports, reviews, meta-analysis, letters, or editorials). Results: Six articles were found eligible after screening the title, abstract and - when necessary the full text for in- and exclusion criteria. All selected studies were case-control studies. Overall, results regarding the presence of CS were divergent. While the majority of patients with chronic traumatic neck pain (i.e. whiplash) are characterized by CS, this is not the case for patients with chronic idiopathic neck pain. The available evidence suggests that CS is not a major feature of chronic idiopathic neck pain. Individual cases might have CS pain, but further work should reveal how they can be characterized. Limitations: Very few studies available. Conclusions: Literature about CS in patients with chronic idiopathic non-traumatic neck pain is rare and results from the available studies provide an inconclusive message. CS is not a characteristic feature of chronic idiopathic and non-traumatic neck pain, but can be present in some individuals of the population. In the future a subgroup with CS might be defined, but based on current knowledge it is not possible to characterize this subgroup. Such information is important in order to provide targeted treatment

Influence of hip angle on muscle activity and lumbar posture in dentists during a dental screening task

Introduction: To avoid potentially painful end-range positions and to facilitate activation of trunk muscles, adopting neutral lumbar spine postures has been emphasized. Such a neutral posture is obtained through positioning the lower lumbar spine into slight anterior tilt and slight lumbar lordosis while relaxation of the thoracic spine is maintained. Maintaining this neutral posture was found to be easier while sitting with an open hip angle. Whereas in the past dental stools facilitated a 90° hip angle, recently different stools have been developed to allow a greater hip angle. Next to saddle stools, for dentistry also the Ghopec stool has been developed. The latter stool comprises a seat pan consisting of a horizontal rear part for the pelvis and an inclinable sloping down front part for the upper legs, with a vertically and horizontally adjustable back rest. Aim: to evaluate the influence of different sitting modes on muscle activity and lumbar posture in dentists during work. M&M: This study compared muscle activity and lumbar posture on a standard stool with, a saddle stool without and the Ghopec with back rest. Twenty five participants completed a dental screening task on all stools in one session. Muscle activity was assessed with surface electromyography and lumbar posture using the BodyGuardTM. Results: Lumbar posture was most close to neutral on the Ghopec stool, whereas sitting on a standard or saddle stool resulted in a respectively more flexed or extended posture. Generally, sitting with a 90° hip angle (standard stool) resulted in higher activation of back muscles while sitting with a 125° hip angle (saddle stool and Ghopec) activated abdominal muscles to a higher degree, although less in the presence of a backrest (Ghopec). Conclusion: To maintain neutral posture, the Ghopec is considered the most suitable of the 3 stools investigate