| 1. |
- Eriksson, Per-Olof, et al.
(författare)
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Deranged jaw-neck motor control in whiplash-associated disorders
- 2004
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 112:1, s. 25-32
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Tidskriftsartikel (refereegranskat)abstract
- Recent findings of simultaneous and well coordinated head-neck movements during single as well as rhythmic jaw opening-closing tasks has led to the conclusion that 'functional jaw movements' are the result of activation of jaw as well as neck muscles, leading to simultaneous movements in the temporomandibular, atlanto-occipital and cervical spine joints. It can therefore be assumed that disease or injury to any of these joint systems would disturb natural jaw function. To test this hypothesis, amplitudes, temporal coordination, and spatiotemporal consistency of concomitant mandibular and head-neck movements during single maximal jaw opening-closing tasks were analysed in 25 individuals suffering from whiplash-associated disorders (WAD) using optoelectronic movement recording technique. In addition, the relative durations for which the head position was equal to, leading ahead of, or lagging behind the mandibular position during the entire jaw opening-closing cycle were determined. Compared with healthy individuals, the WAD group showed smaller amplitudes, and changed temporal coordination between mandibular and head-neck movements. No divergence from healthy individuals was found for the spatiotemporal consistency or for the analysis during the entire jaw opening-closing cycle. These findings in the WAD group of a 'faulty', but yet consistent, jaw-neck behavior may reflect a basic importance of linked control of the jaw and neck sensory-motor systems. In conclusion, the present results suggest that neck injury is associated with deranged control of mandibular and head-neck movements during jaw opening-closing tasks, and therefore might compromise natural jaw function.
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| 2. |
- Häggman-Henrikson, Birgitta, et al.
(författare)
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Endurance during chewing in whiplash-associated disorders and TMD.
- 2004
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 83:12, s. 946-50
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Tidskriftsartikel (refereegranskat)abstract
- We have previously shown an association between ncck injury and disturbed jaw function. This study tested the hypothesis of a relationship between neck injury and impaired endurance during chewing. Fifty patients with whiplash-associated disorders (\VAD) were compared with 50 tcmporomandibular disorders (TMD) patients and 50 healthy subjects. Endurance was evaluated during unilateral chewing of gum for 5 min when participants reported fatigue and pain. Whereas aH healthy suhjects complcted the task, 1/4 of the TMD and a majority of the \VAD patients discontinued the task. A majority of the WAD patients also reported fatigue and paln. These ndings suggest an association between neck injury and reduced functional capacity of the jaw motor system. From the results, we propose that routinc cxamination of ‘VAD patients should include jaw function and that an endurance test as described in this study could also be a useful tool for nondental professionals.
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| 3. |
- Häggman-Henrikson, Birgitta, et al.
(författare)
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Head Immobilization can Impair Jaw Function
- 2006
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 85:11, s. 1001-1005
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Tidskriftsartikel (refereegranskat)abstract
- Findings that jaw-opening/-closing relies on both mandibular and head movements suggest that jaw and neck muscles are jointly activated in jaw function. This study tested the hypothesis that rhythmic jaw activities involve an active repositioning of the head, and that head fixation can impair jaw function. Concomitant mandiular and head-neck movements were recorded during rhythmic jaw activities in 12 healthy adults, with and without fixation of the head. In four participants, the movement recording was combined with simultaneous registration of myoelectric activity in jaw and neck muscles. The results showed neck muscle activity during jaw opening with and without head fixation. Notably, head fixation led to reduced mandibular movements and shorter duration of jaw-opening/-closing cycles. The findings suggest recruitment of neck muscles in jaw activities, and that head fixation can impair jaw function. The results underline the jaw and neck neuromuscular relationship in jaw function.
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| 4. |
- Häggman-Henrikson, Birgitta, et al.
(författare)
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Head movements during chewing : relation to size and texture of bolus.
- 2004
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Ingår i: Journal of Dental Research. - : SAGE Publications. - 0022-0345 .- 1544-0591. ; 83:11, s. 864-868
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Tidskriftsartikel (refereegranskat)abstract
- Coordinated manibular and head-neck movements during jaw opening-closing activities suggest a close functionallinkage between the jaw (Th and the neck regions. The present study al., investigated whether size and texture of bolus can texl intluence head-neck behavior during chewing. Ho' Using an optoelectronic 3-D recording technique, et , we analyzed concomitant mandibular and head- and neck movements in 12 healthy adults chewing small (3 g) and large (9 g) boluses of chewing resl gum and Optosil. The main finding was a head sim extension during chewing, the amount of which cer' was related mainly to bolus size. Furthermore, suc each chewing cycle was accompanied not only by ya" mandibular movements, but a1so by head mol extension-flexion movements. Larger head the movement amplitudes were correlated with larger but size and, to some extent, also with harder texture yet of the bolus. The results suggest that head-neck of t behavior during chewing is modulated in response acCI to changes in jaw sensory-motor input.
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| 5. |
- Kalezic, Nebojsa, et al.
(författare)
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Cardiovascular and muscle activity during chewing in whiplash-associated disorders (WAD)
- 2010
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Ingår i: Archives of Oral Biology. - : Elsevier BV. - 0003-9969 .- 1879-1506. ; 55:6, s. 447-453
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Tidskriftsartikel (refereegranskat)abstract
- Objective. The present study aimed to elucidate possible physiological mechanisms behind impaired endurance during chewing as previously reported in WAD. We tested the hypothesis of a stronger autonomic reaction in WAD than in healthy subjects in response to dynamic loading of the jaw-neck motor system. Design. Cardiovascular reactivity, muscle fatigue indicies of EMG, and perceptions of fatigue, exhaustion and pain were assessed during standardised chewing. Twenty-one WAD subjects and a gender/age matched control group participated. Baseline recordings were followed by two sessions of alternating unilateral chewing of a bolus of gum with each session followed by a rest period. Results. More than half of the WAD subjects terminated the test prematurely due to exhaustion and pain. In line with our hypothesis the chewing evoked an increased autonomic response in WAD exhibited as a higher increase in heart rate as compared to controls. Furthermore, we saw consistently higher values of arterial blood pressure for WAD than for controls across all stages of the experiment. Masseter EMG did not indicate muscle fatigue nor were there group differences in amplitude and mean power frequency. Pain in the WAD group increased during the first session and remained increased, whereas no pain was reported for the controls. Conclusion. More intense response to chewing in WAD might indicate pronounced vulnerability to dynamic loading of the jaw-neck motor system with increased autonomic reactivity to the test. Premature termination and autonomic involvement without EMG signs of muscle fatigue may indicate central mechanisms behind insufficient endurance during chewing.
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| 6. |
- Zafar, Hamayun, et al.
(författare)
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Impaired positioning of the gape in whiplash-associated disorders
- 2006
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Ingår i: Swedish Dental Journal. - 0347-9994. ; 30:1, s. 9-15
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Tidskriftsartikel (refereegranskat)abstract
- We have previously introduced anew concept for natural jaw function suggesting that "functional jaw movements" are the result of coordinated jaw and neck muscle activation, leading to simultaneous movements in the temporomandibular, atlanto-occipital and cervical spine joints. Thus, jaw function requires a healthy state of both the jaw and the neck motor systems. The aim of this study was to examine the positioning of the gape in space during maximal jaw opening at fast and slow speed in healthy as well as whiplash-associated disorders (WAD) individuals. A wireless optoelectronic technique for three-dimensional movement recording was used. Subjects were seated in an upright position,with back support up to the mid-scapular level without headrest. The position of the gape in space was defined as the vertical midpoint position of the gape at maximal jaw opening (MP). In healthy, the MP generally coincided with the reference position at the start of jaw opening. In the WAD group, the MID was significantly lower than the reference position. No sex or speed related differences were found. The results suggest that both the width and orientation of the gape in space relies on coordinated jaw and neck muscle activation and mandibular and head-neck movements. This study also suggests an association between neck pain and dysfunction following trauma, and reduced width and impaired positioning of the gape in space. Finally, the MP seems to be a useful marker in evaluation of the functional state of the jaw-neck motor system.
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