title: Influence of experimental palatal plate on mandibular position during continuous phonation of [n].
abstract: OBJECTIVE
  This study aimed to determine the influence of the thickness of a palatal plate on the mandibular position during continuous phonation of the sound [n].
  
  
  METHODS
  Eleven healthy volunteers (10 males and 1 female; 24-36 years of age, mean age 26.4 years) were recruited from dental students. They were instructed to pronounce [n] continuously under six conditions: wearing a palatal plate with a thickness of 0.3, 1.5, 3.0, 5.0, and 10.0mm, and without a plate (control). Mandibular movement during pronunciation was simultaneously recorded by a K-7 mandibular kinesiograph. Their mandibular positions in the physiologic rest position were also recorded. The distance between the incisal edge of maxillary and mandibular anterior teeth both in vertical and antero-posterior directions during continuous phonation of [n] (interocclusal distance) under all six conditions were measured and compared.
  
  
  RESULTS
  Interocclusal distance tended to increase in both vertical and antero-posterior directions as the thickness of the palatal plates increased. There were statistically significant differences in the mandibular position both in vertical and antero-posterior directions during continuous phonation of [n] between the control condition and those wearing a palatal plate with a thickness of 10.0mm.
  
  
  CONCLUSIONS
  The mandibular position determined by the phonetic method employing continuous [n] as a test pronunciation was affected by the thickness of the palatal plates inserted into the mouth. However, its influence was not significant when the thickness of the palatal plates was 5mm or less.
authors.affiliation: Department of Prosthodontics, Peking University, School of Dentistry, Beijing, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.forename: Mineyo
authors.initials: M
authors.lastname: Sone
authors.forename: Hironobu
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Katsura
authors.initials: K
authors.lastname: Ohmori
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Yaka
authors.forename: Shuji
authors.initials: S
authors.lastname: Ohkawa