title: Neck and shoulder muscle activation patterns among dentists during common dental procedures.
abstract: BACKGROUND
  Dental practitioners often suffer musculoskeletal disorders (MSDs) in the upper extremity due to the static, repetitive and precise nature of work. Knowledge regarding muscle activation patterns in that region is essential in understanding the mechanism behind the upper extremity MSDs. However, the literature review has revealed few studies with such a focus.
  
  
  OBJECTIVE
  This study aims to examine the inter-relationship of the exertion levels of eleven upper extremity muscles during common dental procedures. This provides insights into the interactive utilization patterns of the targeted muscles and their implications in the development of MSDs.
  
  
  METHODS
  Twelve dentists were recruited. Electromyography (EMG) signals of sampled muscles were collected for 32 trials, i.e. combinations of independent variables (IVs) (and levels): posture (2), precision (2), line of vision (4), and grip type (2). Multivariate statistical methods were used to analyze the effects of IVs on muscle coactivity patterns.
  
  
  RESULTS
  MANOVA showed significant main effects and a 2-way interaction between precision and grip type. Most notably, the upper trapezius exhibited consistently higher utilization than other muscles during a seated posture.
  
  
  CONCLUSIONS
  Seated postures, preferred by dentists as a way to relieve back stress, may contribute to the development of shoulder or neck MSDs due to elevated upper trapezius exertions.
authors.affiliation: Industrial and Manufacturing Engineering and Technology Department, Bradley University, Peoria, IL, USA.
authors.forename: Regina
authors.initials: R
authors.lastname: Pope-Ford
authors.affiliation: The Ergonomics and Biomechanics Laboratory, Department of Industrial and Systems Engineering, North Carolina A&T State University, Greensboro, NC, USA.
authors.forename: Zongliang
authors.initials: Z
authors.lastname: Jiang
mesh_terms: D003813:Dentistry; D004576:Electromyography; D005260:Female; D006225:Hand / Q000502:physiology; D006801:Humans; D008297:Male; D009334:Neck Muscles / Q000502:physiology*; D011187:Posture / Q000502:physiology; D012782:Shoulder; D064171:Superficial Back Muscles / Q000502:physiology*
keywords: Electromyography; musculoskeletal disorders; myoelectric; neck and shoulder pain; upper trapezius