Mastication, Deglutition, & Dysphagia PDF

Mastication, Deglutition & Dysphagia Oral and Dental Science Miss Felix GDC Learning Outcomes 1.1.5 Describe relevant and appropriate dental, oral, craniofacial and general anatomy and explain their application to patient management 1.1.6 Describe relevant and appropriate physiology and e...

Mastication, Deglutition & Dysphagia Oral and Dental Science Miss Felix GDC Learning Outcomes 1.1.5 Describe relevant and appropriate dental, oral, craniofacial and general anatomy and explain their application to patient management 1.1.6 Describe relevant and appropriate physiology and explain its application to patient management Related topics:  Muscles of mastication  Tongue  Saliva & Salivation  Palate  Xerostomia  Regional anatomy Intended Learning Outcomes By the end of this lecture you should be able to: 1. Describe the processes of mastication and deglutition, in both health and disease 2. Outline the structures involved in both processes 3. Outline the disorders that may affect the normal process of deglutition 4. Outline considerations in the dental management of patients with dysphagia Make sure you have a drink and some food as you work through this lecture! Mastication What do you understand by the term ‘mastication’? Why is it important? What role do these structures play in this process? Muscles of Teeth Tongue Lips mastication If a patient is limited by one or more of these structures, how might this impact on their ability to eat? Masticatory Cycle Occurs in 3 phases: Opening Phase Closing Phase Occlusal Phase  Food is broken down by the teeth and the digestive process begins Which enzyme is present in saliva to start the digestive process? Mixing with saliva, the food is formed into a bolus ready for swallowing The length of time that food stays in the mouth is greatly dependent on the consistency of the food Deglutition [The normal swallow] Deglutition (the normal swallow) The action of swallowing It takes about 7 seconds for the bolus to go from the oral cavity into the stomach Simultaneously, the openings between the oropharynx & nasopharynx and between the laryngopharynx & larynx are closed Two types of swallow: Automatic swallow (dry swallow) Voluntarily initiated swallow (food and drink) The co-ordination of the components of swallowing is considered to be the function of a swallow centre situation in the medulla (brain stem) Swallowing is a reflex initiated by the stimulation of tactile receptors in the area of the oropharynx Afferent impulses travel through the trigeminal and glossopharyngeal nerves to the swallow centre Here they initiate motor stimuli and accessory nerves to the soft palate and pharynx to start rising so as to close off the nose and pharynx Swallowing begins This involves: 25 skeletal muscles Multiple components working together: Arousal of Food Saliva flow appetite stimulates Taste buds Sensation on the tongue Swallowing Structures What oral structures do you think play a role in swallowing? Go on, take another bite of food, or a sip of drink! This time see if you can identify any of the structures involved in swallowing… Lips Closure of the mouth and lips is necessary to create intra-oral pressure Tongue Forms bolus of food and channels it down a groove made in the tongue and propels the bolus towards the fauces Soft palate Rises to block off the nasopharynx Hyoid bone A horseshoe shaped bony arch It supports the tongue and gives During swallowing the larynx is suspended from the tip of the attachment to its numerous elevated by contraction of the styloid process of the temporal muscles hyoid musculature bone by stylohyoid ligaments Epiglottis Is lowered by the moving bolus to help protect the airway Vocal cords Close Cricoid cartilage (cricopharyngeal sphincter) Relaxes to allow food to enter the oesophagus Phases of Swallowing 1. Ninja Nerd Lectures- this video gives a good level of detail about each of the swallowing stages without being overwhelming incorporating the use of great diagrams. Would recommend watching before continuing! It also incorporates other regional anatomy such as: Muscles of Muscles of Nerve the tongue mastication innervations 2. This video by Sam Webster is a good one to follow on from after the one above as he uses anatomical models in his explanation which helps give a 3D perspective. He also takes a look at the gag reflex. Swallowing occurs in three phases Swallowing occurs in three phases: 1. Oral phase 3. 2. Pharyneal (inc executive Oesophageal phase phase) phase It is initiated voluntarily and then completed by an involuntary (reflex) action. Where do you think the process moves from voluntary in involuntary? Oral Phase (feeding stage) Lips are closed & the bolus is Nasal breathing prepared continues, the (mastication and larynx is open and drenching in saliva the hypopharyngeal shapes the bolus) sphincter is closed Voluntary- can be It is kept to the Soft palate is stopped at will front of the mouth lowered away from the discouraging food nasopharynx area from the nasopharynx Oral Phase (executive phase) The bolus is propelled backwards along tongue. When it arrives on the base of the From now on the subsequent tongue it is projected past the pillars of 01 the fauces into the pharynx. The fauces contract and the swallow reflex is activity is controlled by reflex and cannot be interrupted 04 activated (initiating the pharyngeal phase) voluntarily The soft palate rises and 02 blocks off the nasopharynx Respiration ceases 03 Pharyngeal Phase (swallowing phase) The swallow reflex has been initiated by receptors in the pillars of fauces in the oropharynx Breathing has ceased and the soft palate has closed the nasopharynx The larynx is elevated by the raising of the hyoid bone and associated muscles The glottis is closed (the opening between vocal cords). As the tongue forces food back, the bolus also tilts the epiglottis backwards for further protection of the trachea At the same time the hypopharyngeal sphincter is opened by contraction of the skeletal muscles at the beginning of the oesophagus and allows the bolus to pass The sphincter is closed when not swallowing by passive elastic tension Oesophageal Phase Bolus is transported down the oesophageal tube to the stomach by ‘perastaltic waves’ of the smooth muscle Nerve Innervation Olfactory Nerve I Smell Trigeminal Nerve V Sensation from the face and muscles of mastication Motor function to the muscles of mastication Facial Nerve VII Taste from the anterior two thirds of the tongue Motor function to the muscles of the face Glossopharyngeal Nerve IX General sensation from the: posterior one third of the tongue soft palate palatine tonsils pillars of fauces pharynx Taste sensation from the posterior one third of the tongue Motor function to the: pharyngeal constrictors stylopharyngeus muscle Vagus Nerve X General sensation from the larynx Motor function to the: Palate pharynx (part) Larynx Autonomic to the oesophagus Accessory Nerve XI Motor function supply supplementary to vagus Motor function supply to the: Sternomastoid trapezius (muscles of head control) Hypoglossal Nerve XII Motor function to the intrinsic and extrinsic muscles of the tongue Dysphagia [Swallowing difficulties] What do you understand by the term ‘dysphagia’? What do you think the most common cause of dysphagia might be? Clue: When might you have experienced problems with swallowing? The most common cause is due to infection of the throat, producing pain on swallowing and inflammatory swelling of the mucosa. According to the Stroke Association, some of the possible signs of dysphagia include: Food or drink going Coughing when Still having food or down the wrong Feeling that food is drink left in your you’re eating or way stuck in your throat mouth after you’ve drinking swallowed Taking a long time Having to Being short of Dribbling to swallow or finish swallowing a lot to breath while a meal clear your throat swallowing A croaky or ‘wet’ Not being able to sounding voice chew food properly Causes Dysphagia can be caused by: A condition that results in weakening, or damaging, the muscles and nerves used in swallowing Stroke Cerebral Palsy Parkinson’s disease Head Injury A structural abnormality Cleft Palate Bony outgrowths Can you come up with an example for each cause? Other causes include: Head and neck cancer, including their treatments Infections or irritations Dementia, memory loss and cognitive decline Drugs (professional and recreational) and alcohol use Age related changes Disorders of the Pharyngeal Stage If there is a delay in the swallow reflex this can lead to material being able enter the pharynx before the reflex has been triggered. This leaves the patient at risk of items falling into an unprotected airway. What protective measures won’t have occurred? Reduced pharyngeal peristalsis can lead to residue remaining in the pharynx and then potentially entering the airway after the swallow has been completed and normal breathing resumes. Disorders of the Oesophageal Stage If there is reduced peristalsis then material remaining in the oesophagus may be refluxed leading to potential aspiration. This is also a risk if the patient is positioned poorly during or after eating- why? Abnormal Swallow [Associated Problems] Infection Aspiration occurs when food or liquids enters the larynx and passes through the vocal chords which can result in a chest infection Whilst microscopic amounts may be aspirated in normal individuals, if a large volume of food or liquid is aspirated then there is an increased risk of pneumonia Aspiration can occur at any stage during swallowing: Before (if there is an impairment preventing material being maintained in the mouth) During (if there are any impairments, for example, to the tilting of the epiglottis or closing of the vocal chords) After (if residue remains in pharynx it may be inhaled) Dehydration If unable to swallow safely this may lead to an insufficient intake of fluids Why might this be? Dehydration can lead to other complications such as an increased susceptibility to infection, mental confusion and reduced saliva flow. Malnutrition Similar to dehydration, malnutrition (or a reduction in adequate nutrition) may result if an individual is unable to swallow safely leading to an insufficient intake. They may be embarrassed by their swallowing difficulties, which may cause them to withdraw from social interaction during mealtimes, or worry about choking. Risk of malnutrition may be compounded by the psychological effects of dysphagia. Gastric reflux and heartburn Contents from the stomach can be forced past the cardiac sphincter into the lower end of the oesophagus, to be returned to Cardiac sphincter the stomach by reflux peristalsis. The stratified squamous epithelium of the oesophagus has no protection against the acid contents of the stomach, and acid reflux produces inflammation and even ulceration of the oesophagus. This is felt as burning pain in the epigastrium and behind the sternum. Dental Management of Dysphagia Dental considerations What impacts do you think dysphagia can have on oral health? Dysphagia can contribute to: Increase plaque Reduced oral Increased caries and calculus Dry mouth clearance risk deposits Did you get anything else? Dental Management Based on your current knowledge and experience, what considerations would you make to the following areas for a patient presenting with dysphagia? Provision of Treatment Patient Assessment (Periodontal/Restorative) Patient Positioning Additional Considerations Preventative Advice This lecture by Grace Kelly might help get you started Patient Assessment Patient Positioning Provision of Treatment What is most Is dysphagia part of a wider (Periodontal/Restorative) medical condition? comfortable for the Careful use of water: What is the extent of their patient? Power driven scaler Semi-supine dysphagia? 3-in-1 Altered diet/OH Fast handpiece difficulties/impact on day-to- …avoid where possible day etc Good suction (saliva ejector Preventative Advice and HVS) Prevention is key to avoid Rubber dam to protect lengthy/complex dental airway procedures Fast setting materials Consider: Non-foaming toothpastes Not wetting toothbrush Additional Considerations Consider liquid preparations if AB needed Avoid mouthwashes Care with viscosity when taking impression Aspirating toothbrushes Communication/signalling Diet analysis and advice Frequent breaks Patient’s ability to swallow saliva Additional Resources Leaflets Dealing with swallowing problems. The Stroke Association. Available at: https://www.stroke.org.uk/sites/default/files/publications/f05_swallowing_proble ms_v3.1_may_2020.pdf A Complete Guide to Swallowing Problems After a Stroke. The Stroke Association. Available at: https://www.stroke.org.uk/sites/default/files/publications/f05cg_cg_to_swallowin g_problems_v2_may_2020.pdf YouTube Sam Webster- Swallowing anatomy (pharynx) https://youtu.be/0HklsPDqkmg Websites https://swallowingdisorderfoundation.com/ References Stroke Association. Available at: https://www.stroke.org.uk/ Dysphagia. National Institute on Deafness and Other Communication Diseases (updated March 2017). Accessed 1st Feb 2021. Available at: https://www.nidcd.nih.gov/health/dysphagia Matsuo, K., & Palmer, J. B. (2008). Anatomy and physiology of feeding and swallowing: normal and abnormal. Physical medicine and rehabilitation clinics of North America, 19(4), 691–vii. https://doi.org/10.1016/j.pmr.2008.06.001