Does head protraction affect the range of vertical jaw opening? An experimental study.
Item
- Title
- Does head protraction affect the range of vertical jaw opening? An experimental study.
- Author(s)
- Tseng, F
- Abstract
- Does head posture affect the function of the TMJ? The TMJ and the C-spine are not directly linked by any muscles or ligaments, (Schunke, 2010) the existing literature contains two studies (Higbic, 1999) (La Touche, 2011) that measured whether there was a cause-and-effect relationship, between maximal head protraction and retraction, on vertical jaw opening. But those studies did not measure how gradual increments of head protraction may affect TMJ function. Therefore, this will be an experimental investigation to gather primary data. The aim: to investigate whether gradual increments of head protraction affects maximal jaw opening. There will be a hypothesis A and B, because two different approaches of inferential statistics were used to analyze the data: one to test for differences, one to test for correlation.Study design: a same subject, multiple conditions design. Methodology: Data was collected from 12 males and 25 females (41.6 + /- 15.7 years). A measurement of vertical jaw opening was performed on each subject with the head in neutral, then I.5cm protraction, and then 3cm protraction. The subject was asked to assume each of the three head postures three separate times; therefore, nine measurements were taken per subject. Therabite range of motion rulers with millimeter increments, were used to measure jaw opening. A cervical range of motion instrument (CROM) instrument with a forward head arm, and a vertebra locator (PAA, 2009), was used to determine head position. Results: A I -way ANOVA test yielded a p-value >0.05, which meant that there was no significant difference between any of the groups. The test for Pearson's correlation coefficient yielded an r-value of r=0.10l; the probability of the two data sets being uncorrelated was p=O.29, and a scatter graph showed that the data points were scattered a long way either side of the trend line all of this showed that there was little to no correlation between head protraction and vertical jaw opening. These results were not judged to be clinically significant either. The intraclass correlation coefficient for intra-rater reliability for repeated measurements of jaw opening was relatively high, at 0.927. which matched the reported rate of intra-rater reliability in published research that had used similar equipment. (Higbie 1999) (La Touche, 2011) Conclusions: Neither null hypothesis A nor B could be rejected. Head protraction was not found to cause a significant difference in a person's range of vertical jaw opening and the degree of head protraction was not found to correlate with changes in a person's range of vertical jaw opening. No definite conclusions can be drawn. The definition of "neutral" head posture in this study differed from the definition in the published research (Higbie, 1999) (La Touche, 2011 ), therefore it was difficult to draw direct comparisons with their findings. And although the intra-rater reliability was found to be high in this experiment, on retrospect, many aspects of the methodology could have been improved, to reduce the frequency of occurrence of various random errors. No generalization to the wider population could be made. The external validity of the results was low, due to the small sample size, with unbalanced representation across the different genders and ages. The sample group had also been taken from a population with characteristics that may have been slightly different to that of the general public.
- presented at
- European School of Osteopathy
- Date Accepted
- 2013
- Date Submitted
- 20.1.2015 16:42:59
- Type
- osteo_thesis
- Language
- English
- Submitted by:
- 62
- Pub-Identifier
- 15475
- Inst-Identifier
- 1229
- Keywords
- Jaw ROM.
- Recommended
- 0
- Item sets
- Thesis
Tseng, F, “Does head protraction affect the range of vertical jaw opening? An experimental study.”, Osteopathic Research Web, accessed May 17, 2024, https://www.osteopathicresearch.com/s/orw/item/689