Masticatory Side-switch and Mixing Ability.
Condition: Chewing Problem; Mastication Disorder
Study type: Interventional

Summary: 
      The main aim of this cross-over intervention study is to assess the effect of masticatory
      side-switch frequency on different aspects of masticatory function, including masticatory
      mixing ability and rhythm. A secondary aim is to explore the subjective perception of taste,
      muscular fatigue, and saliva production through a VAS. Thirty-six volunteers recruited for
      convenience, among students of the Degree of Dentistry of the Faculty of Medicine and Health
      Sciences of the University of Barcelona, will perform 6 tests, each consisting of 2 assays,
      chewing a two-coloured chewing gum, during 40 masticatory cycles. The tests will be
      randomised masticatory sequences of "free-style", "unilateral-right", "unilateral-left",
      switching the chewing side at 5% "G05", at 15% "G15" and at 25% "G25". Video recordings of
      these tests will be made to later assess, on slow playback, the change of the chewing side
      and the masticatory rhythm. The masticatory mixing ability will be determined through the
      scanning and posterior analysis of the red-channel in the histogram plug-in in "ImageJ" (R).
    

Detailed description: 
      This this cross-over intervention study aims to assess the effect of masticatory side-switch
      frequency on different objective aspects of masticatory function, including masticatory
      mixing ability and rhythm, as well as the subjective perception of taste, muscular fatigue,
      and saliva production through a VAS. Each of the thirty-six volunteers recruited for
      convenience, among students of the Degree of Dentistry of the Faculty of Medicine and Health
      Sciences of the University of Barcelona, will perform 6 tests, each consisting of 2 assays,
      chewing a two-coloured chewing gum, during 40 masticatory cycles. One test involves freestyle
      mastication in which the participant will be asked to masticate the chewing gum. Two tests
      involve chewing the gum unilaterally (i.e., only on the right-hand side, and only on the
      left) varying the order of these assays. In the last three tests, the volunteer will switch
      chewing side in 5% (G05), 15% (G15), or 25% (G25) respectively; the sequence of the assays
      will be randomized. Twenty-four of these volunteers will be randomly selected to repeat these
      tests after a period of two weeks. The masticatory mixing ability will be determined through
      the "mixing capacity index" (MCI), obtained from through the scanning and posterior analysis
      of the red-channel in the histogram plug-in in "ImageJ" (R), and the masticatory rhythm will
      be assessed through the masticatory frequency as the ratio of masticatory cycle number to
      masticatory time. The control variables will include age and sex.
    

Intervention name(s): F; R; L; G05; G15; G25
Intervention type(s): Behavioral; Behavioral; Behavioral; Behavioral; Behavioral; Behavioral
Intervention description(s): The participant will be asked to chew the two-coloured chewing gum naturally.; The participant will be asked to chew the two-coloured chewing gum on the right-side.; The participant will be asked to chew the two-coloured chewing gum on the left-side.; The participant will be asked to chew the two-coloured chewing gum changing the side in 5%.; The participant will be asked to chew the two-coloured chewing gum changing the side in 15%.; The participant will be asked to chew the two-coloured chewing gum changing the side in 25%.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: Chewing side; Masticatory side-switch; Mastication; Masticatory rhythm; Masticatory performance; Masticatory mixing ability