title: Masticatory efficiency and muscular activity in removable partial dental prostheses with different cusp angles.
abstract: BACKGROUND
  The loss of posterior teeth has a negative effect on the masticatory efficiency and activity of mastication muscles. How these muscles are affected by partial removable dental prostheses (PRDPs) with different cusp angles is unknown.
  
  
  OBJECTIVE
  The purpose of this clinical study was to evaluate the influence of different cusp angles, with anatomic (33 degrees), semianatomic (20 degrees), and nonanatomic teeth (0 degree), on the masticatory efficiency and muscular activity of participants receiving mandibular bilateral distal PRDPs.
  
  
  METHODS
  Fifteen participants consented to the evaluation of masticatory efficiency and electromyographic (EMG) activity with a PRDP with a unified bilateral design. The cusp angles of the artificial teeth were randomly changed from anatomic (33 degrees), semianatomic (20 degrees), and nonanatomic teeth (0 degree). Masticatory efficiency was evaluated by recording 5 parameters, including number of strokes, and time of mastication while the EMG activities of the masseter and temporalis muscles, measured using surface electromyography. The data were analyzed with 1-way ANOVA and the Tukey multiple post hoc test with statistical software (α=.05).
  
  
  RESULTS
  With regard to masticatory efficiency, PRDPs with anatomic and semianatomic teeth exhibited higher masticatory efficiency than those with nonanatomic teeth, whereas no significant differences were found between PRDPs with anatomic and semianatomic teeth. With respect to EMG activity, the least EMG activity was observed in PRDPs with anatomic teeth, whereas the highest activity was observed with nonanatomic teeth. No significant differences were found between the effect of PRDPs with anatomic and semianatomic teeth on masseter activity.
  
  
  CONCLUSIONS
  Changing the cusp angle from 33 to 20 degrees in PRDPs did not influence the masticatory efficiency or the EMG activity of the masseters. However, it did lead to increased EMG activities of the temporalis muscle. PRDPs with nonanatomic teeth were associated with a significant decrease in masticatory efficiency accompanied by a significant increase in EMG activity.
authors: Lecturer, Department of Prosthodontics, College of Dentistry, Aljouf University, Sakakah, Saudi Arabia. Electronic address: dr.mohammed.assayed@gmail.com.
authors: Mohammed Assayed
authors: MA
authors: Mousa
authors: Assistant Professor, Department of Radiology and Oral Medicine, College of Dentistry, Aljouf University, Aljouf University, Sakakah, Saudi Arabia.
authors: Santosh
authors: S
authors: Patil
authors: Professor, Department of Restorative Dentistry, Warwick Medical School, University of Warwick, Warwick, United Kingdom.
authors: Edward
authors: E
authors: Lynch
mesh_terms: D000328:Adult; D003766:Dental Occlusion; D003832:Denture, Partial, Removable / Q000009:adverse effects*; D004576:Electromyography; D005502:Food; D006801:Humans; D008409:Mastication / Q000502:physiology*; D008410:Masticatory Muscles / Q000502:physiology*; D008875:Middle Aged; D055815:Young Adult