title: Quantitative evaluation of toothbrush and arm-joint motion during tooth brushing.
abstract: OBJECTIVE
  It is very difficult for dental professionals to objectively assess tooth brushing skill of patients, because an obvious index to assess the brushing motion of patients has not been established. The purpose of this study was to quantitatively evaluate toothbrush and arm-joint motion during tooth brushing.
  
  
  METHODS
  Tooth brushing motion, performed by dental hygienists for 15 s, was captured using a motion-capture system that continuously calculates the three-dimensional coordinates of object's motion relative to the floor. The dental hygienists performed the tooth brushing on the buccal and palatal sides of their right and left upper molars. The frequencies and power spectra of toothbrush motion and joint angles of the shoulder, elbow, and wrist were calculated and analyzed statistically.
  
  
  RESULTS
  The frequency of toothbrush motion was higher on the left side (both buccal and palatal areas) than on the right side. There were no significant differences among joint angle frequencies within each brushing area. The inter- and intra-individual variations of the power spectrum of the elbow flexion angle when brushing were smaller than for any of the other angles.
  
  
  CONCLUSIONS
  This study quantitatively confirmed that dental hygienists have individual distinctive rhythms during tooth brushing. All arm joints moved synchronously during brushing, and tooth brushing motion was controlled by coordinated movement of the joints. The elbow generated an individual's frequency through a stabilizing movement.
  
  
  CONCLUSIONS
  The shoulder and wrist control the hand motion, and the elbow generates the cyclic rhythm during tooth brushing.
authors.affiliation: Department of Pediatric Dentistry, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima, 890-8544, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Inada
authors.forename: Issei
authors.initials: I
authors.lastname: Saitoh
authors.forename: Yong
authors.initials: Y
authors.lastname: Yu
authors.forename: Daisuke
authors.initials: D
authors.lastname: Tomiyama
authors.forename: Daisuke
authors.initials: D
authors.lastname: Murakami
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Takemoto
authors.forename: Ken
authors.initials: K
authors.lastname: Morizono
authors.forename: Tomonori
authors.initials: T
authors.lastname: Iwasaki
authors.forename: Yoko
authors.initials: Y
authors.lastname: Iwase
authors.forename: Youichi
authors.initials: Y
authors.lastname: Yamasaki
mesh_terms: D000328:Adult; D001132:Arm / Q000502:physiology*; D003756:Dental Hygienists; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D009068:Movement / Q000502:physiology*; D014099:Toothbrushing