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The masseteric reflex evoked by tooth and denture tapping
P Brodin1, F Fløystrand, J Orstavik
1Department of Physiology and Biochemistry, University of Oslo, Norway.
Journal of Oral Rehabilitation
|July 1, 1991
Summary
Immediate dentures alter the masseter reflex response to tooth tapping. Mucosal mechanoreceptors under the denture may compensate for lost periodontal input, influencing reflex pathways.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Dental Prosthetics
Background:
- The masseter reflex, crucial for mastication, is typically modulated by periodontal mechanoreceptors in natural teeth.
- Immediate dentures replace teeth instantly but alter the sensory input to the trigeminal system.
Purpose of the Study:
- To compare the masseter reflex evoked by tapping natural incisors versus immediate denture teeth.
- To investigate the impact of immediate denture insertion and relining on reflex characteristics.
Main Methods:
- Electromyography (EMG) was used to record the masseter reflex.
- Tapping stimuli were applied to maxillary incisors and then to corresponding immediate denture teeth.
- Thresholds for inhibitory (I-1, I-2, I-3) and excitatory phases were measured before and after denture insertion and after relining.
Main Results:
- Averaged EMG revealed three inhibitory phases (I-1, I-2, I-3) followed by excitation.
- Denture insertion increased the tapping force thresholds for all inhibitory phases and the latency for I-1.
- Relining the denture decreased the threshold for the I-1 phase.
Conclusions:
- Mucosal mechanoreceptors beneath the denture base can functionally substitute for periodontal mechanoreceptors in evoking the masseter reflex.
- These mucosal afferents likely connect to the same central interneurons as periodontal afferents.