Masticatory Side Change and Masticatory Function.

Study Overview
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Brief Summary
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The primary objective of this study is to establish the effect of the frequency of masticatory side switches on masticatory performance. We also want to know the effect of the frequency of masticatory side switches on the masticatory rhythm. Twenty-eight healthy volunteers will undertake masticatory tests, following a series of instructions given at the moment. These volunteers will take a re-test in two-weeks time. The sequence of these tests will be randomized in such a way that, each participant will initially perform an established sequence of freestyle, only-right, and only-left masticatory tests, and then will carry out one of the 6 possible combinations of A1, A3, and A5. These tests will be recorded on video to assess, on slow playback, the change of the chewing side, and the masticatory rhythm.Masticatory performance will be determined by sieving the silicone particles.

Detailed Description
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This crossover intervention study aims to assess the effect of the degree of alternance of the chewing side on various aspects of masticatory function, including masticatory performance and rhythm. Twenty-eight volunteers will take part, recruited for convenience, among friends and relatives of the teachers and students of the Degree of Dentistry of the Faculty of Medicine and Health Sciences of the University of Barcelona. These individuals will perform masticatory tests and, after a period of two weeks, will repeat them as a re-test. Each participant will perform 6 tests, each consisting of 5 assays, chewing a small latex bag containing a few silicone tablets (2 g) during 20 masticatory cycles. One test involves freestyle mastication in which the participant will be asked to chew the latex bag naturally. Two tests involve chewing the bag unilaterally (i.e., right-hand side in one and left-hand side in the other) and the order of their assays will be varied. For the last three tests, the participant will change the chewing side 1 (A1), 3 (A3), or 5 (A5) times respectively; the sequence of the assays will be randomized. The masticatory performance will be determined by the median particle size (MPS), 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.

Official Title
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Relationship Between the Frequency of Masticatory Side Switches and Aspects of Masticatory Function.

Conditions
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Chewing Problem, Mastication Disorder

Intervention / Treatment
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* Behavioral: F
* Behavioral: R
* Behavioral: L
* Behavioral: A1
* Behavioral: A3
* Behavioral: A5


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Older than 18 years old. Natural dentition (minimum 24 teeth). Exclusion Criteria: Active orthodontics treatment. Intraoral pain. Temporomandibular joint pain. Masticatory muscle pain. Large dental restorations. Dental prosthesis.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: F-R/L-A1/A3/A5 Sequence<br>First, 5 freestyle masticatory assays (F). Second, 5 only-right (R) and 5 only-left (L) masticatory assays in the following order (R-L-L-R-R-L-L-R-R-L) Third, 15 masticatory assays changing the side once (A1), three times (A3) or 5 times (A5) in the following order (A1-A3-A5-A5-A3-A1-A1-A3-A5-A5-A3-A1-A1-A3-A5) | Behavioral: F<br>* The participant will be asked to chew the latex bag naturally.<br>Behavioral: R<br>* The participant will be asked to chew the latex bag unilaterally on the right-side.<br>Behavioral: L<br>* The participant will be asked to chew the latex bag unilaterally on the left-side.<br>Behavioral: A1<br>* The participant will be asked to chew the latex bag changing the side once.<br>Behavioral: A3<br>* The participant will be asked to chew the latex bag changing the side three times.<br>Behavioral: A5<br>* The participant will be asked to chew the latex bag changing the side five times.<br>|
| Active Comparator: F-R/L-A1/A5/A3 Sequence<br>First, 5 freestyle masticatory assays (F). Second, 5 only-right (R) and 5 only-left (L) masticatory assays in the following order (R-L-L-R-R-L-L-R-R-L) Third, 15 masticatory assays changing the side once (A1), three times (A3) or 5 times (A5) in the following order (A1-A5-A3-A3-A5-A1-A1-A5-A3-A3-A5-A1-A1-A5-A3) | Behavioral: F<br>* The participant will be asked to chew the latex bag naturally.<br>Behavioral: R<br>* The participant will be asked to chew the latex bag unilaterally on the right-side.<br>Behavioral: L<br>* The participant will be asked to chew the latex bag unilaterally on the left-side.<br>Behavioral: A1<br>* The participant will be asked to chew the latex bag changing the side once.<br>Behavioral: A3<br>* The participant will be asked to chew the latex bag changing the side three times.<br>Behavioral: A5<br>* The participant will be asked to chew the latex bag changing the side five times.<br>|
| Active Comparator: F-R/L-A3/A1/A5 Sequence<br>First, 5 freestyle masticatory assays (F). Second, 5 only-right (R) and 5 only-left (L) masticatory assays in the following order (R-L-L-R-R-L-L-R-R-L) Third, 15 masticatory assays changing the side once (A1), three times (A3) or 5 times (A5) in the following order (A3-A1-A5-A5-A1-A3-A3-A1-A5-A5-A1-A3-A3-A1-A5) | Behavioral: F<br>* The participant will be asked to chew the latex bag naturally.<br>Behavioral: R<br>* The participant will be asked to chew the latex bag unilaterally on the right-side.<br>Behavioral: L<br>* The participant will be asked to chew the latex bag unilaterally on the left-side.<br>Behavioral: A1<br>* The participant will be asked to chew the latex bag changing the side once.<br>Behavioral: A3<br>* The participant will be asked to chew the latex bag changing the side three times.<br>Behavioral: A5<br>* The participant will be asked to chew the latex bag changing the side five times.<br>|
| Active Comparator: F-R/L-A3/A5/A1 Sequence<br>First, 5 freestyle masticatory assays (F). Second, 5 only-right (R) and 5 only-left (L) masticatory assays in the following order (R-L-L-R-R-L-L-R-R-L) Third, 15 masticatory assays changing the side once (A1), three times (A3) or 5 times (A5) in the following order (A3-A5-A1-A1-A5-A3-A3-A5-A1-A1-A5-A3-A3-A5-A1) | Behavioral: F<br>* The participant will be asked to chew the latex bag naturally.<br>Behavioral: R<br>* The participant will be asked to chew the latex bag unilaterally on the right-side.<br>Behavioral: L<br>* The participant will be asked to chew the latex bag unilaterally on the left-side.<br>Behavioral: A1<br>* The participant will be asked to chew the latex bag changing the side once.<br>Behavioral: A3<br>* The participant will be asked to chew the latex bag changing the side three times.<br>Behavioral: A5<br>* The participant will be asked to chew the latex bag changing the side five times.<br>|
| Active Comparator: F-R/L-A5/A1/A3 Sequence<br>First, 5 freestyle masticatory assays (F). Second, 5 only-right (R) and 5 only-left (L) masticatory assays in the following order (R-L-L-R-R-L-L-R-R-L) Third, 15 masticatory assays changing the side once (A1), three times (A3) or 5 times (A5) in the following order (A5-A1-A3-A3-A1-A5-A5-A1-A3-A3-A1-A5-A5-A1-A3) | Behavioral: F<br>* The participant will be asked to chew the latex bag naturally.<br>Behavioral: R<br>* The participant will be asked to chew the latex bag unilaterally on the right-side.<br>Behavioral: L<br>* The participant will be asked to chew the latex bag unilaterally on the left-side.<br>Behavioral: A1<br>* The participant will be asked to chew the latex bag changing the side once.<br>Behavioral: A3<br>* The participant will be asked to chew the latex bag changing the side three times.<br>Behavioral: A5<br>* The participant will be asked to chew the latex bag changing the side five times.<br>|
| Active Comparator: F-R/L-A5/A3/A1 Sequence<br>First, 5 freestyle masticatory assays (F). Second, 5 only-right (R) and 5 only-left (L) masticatory assays in the following order (R-L-L-R-R-L-L-R-R-L) Third, 15 masticatory assays changing the side once (A1), three times (A3) or 5 times (A5) in the following order (A5-A3-A1-A1-A3-A5-A5-A3-A1-A1-A3-A5-A5-A3-A1) | Behavioral: F<br>* The participant will be asked to chew the latex bag naturally.<br>Behavioral: R<br>* The participant will be asked to chew the latex bag unilaterally on the right-side.<br>Behavioral: L<br>* The participant will be asked to chew the latex bag unilaterally on the left-side.<br>Behavioral: A1<br>* The participant will be asked to chew the latex bag changing the side once.<br>Behavioral: A3<br>* The participant will be asked to chew the latex bag changing the side three times.<br>Behavioral: A5<br>* The participant will be asked to chew the latex bag changing the side five times.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Masticatory performance | The masticatory performance will be calculated for each test (free, only-right, only-left, and guided tests). The particles from the 5 assays (10g) will be allowed to dry for 24 h. They will then be passed through a series of 8 sieves of different sizes (sizes are: 0.25, 0.425, 0.85, 2, 2.8, 3.15, 4 and 5.6mm). To allow the particles to pass through the sieves, they will be stirred for 6 min. The weight of the remaining pieces of silicone in each sieve will be weighed and the Median Particle Size (MPS) will be calculated using the Rosin Rammler formula. The MPS or (X50) is the aperture in mm of a theoretic sieve through which 50% of the weight of the particles would pass, therefore, the smaller the value of MPS, the more masticatory performance the individual has. | 1 hour 30 minutes | 
| Masticatory Frequency | Masticatory frequency will be assessed as the ratio of masticatory cycle number to masticatory time (in cycles per minute). | 1 hour 30 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Side Switch Index | The number of side switches during the 20 masticatory cycles for each assay will be determined using slow playback of the video recordings of the freestyle mastication test. In the case that this switch is a change of side from left to right or right to left, we will assign a value of 1. If this switch consists of a change from the right or left to central or vice versa, we will assign a value of 0.5. If there is no change of side, the value assigned to this chewing cycle will be 0. To determine the Side Switch Index, the number of side changes will be divided by the maximum number of changes possible during these 5 assays (95). | 1 hour 30 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Chewing side, Masticatory side switch, Mastication, Masticatory rhythm, Masticatory performance