Читать книгу Practical Procedures in Dental Occlusion - Ziad Al-Ani - Страница 23

This follows mastication, and is a complex co‐ordination of more than 25 pairs of muscles involving the mouth, pharynx, larynx and oesophagus (Miller 1982). The CPG for swallowing is located in the medulla oblongata that contains neurons which trigger, shape, and control the rhythmic swallowing patterns.

Deglutition comprises two phases as discussed by Miller (1982).

1 Oral preparatory phase including the pharyngeal phase (voluntary) – the bolus is formed and the positioning of the bolus posteriorly by the extrinsic muscles of the tongue and mylohyoid muscle propels the food further down.

2 Oesophageal phase (involuntary) – irreversible once initiated and consists of peristaltic contractions.

Once the food enters the stomach, the process of extracting the nutrients begins. Therefore, the impact of not breaking our food down properly does not just stop at missing teeth and aesthetic concerns; there is a greater impact on the overall health of the patient, especially gut health, and this can lead to disturbed sleep and possible triggers for parafunction.

If the input system is the same (we all have PDMRs, etc.), why is there such variability amongst individuals? The variability starts at the higher order level in the brain within the somatosensory system. This is continuously modulated and is not hardwired but plastic, meaning it has the ability to adapt to functional demand which can be affected by cognitive and emotional factors such as stress, etc. The term ‘neuroplasticity’ attempts to clarify this and underlines the need to expand our view of occlusion. Just because we have some individuals with greater adaptability, that does not give us carte blanche to perform less than optimal occlusal treatment. Then we have patients who are occlusally hypervigilant whom you would assume have a greater occlusal perception but that doesn't appear to be case; rather, the thoughts and emotions accompanying the altered occlusion appear to be more significant (Klineberg and Eckert 2015).