Edentulism

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Edentulism is the condition of being completely toothless. The relevance and functionality of the teeth we all possess can be easily overlooked, amongst the extensive list of beneficial properties ascribed to teeth we shall be looking at:

1. the aid to facial structure
2. the impact upon the aesthetics of the face
3. the symbiotic relationship with the tempero-mandibular joint
4. the importance with regards to speech
5. how it forms the foundation for the alveolar ridge
6. mastication

“The natural teeth and their supporting bone make an important contribution to the contours of the face.” (Owall, Kayser, Carlson, (1996))

Contents 1 Facial Structure 2 Aesthetics 3 Tempero-Mandibular Joint 4 Speech 5 Ridge Resorption 6 Masticatory Efficiency 7 Bibliography

[edit] Facial Structure

After four to five years of untreated edentulist muscle tone and skin elasticity will have greatly diminished, the follow on of this is the appearance of a shrunken like effect of the face paired with wrinkling. After such a long period of time it can be difficult to make accurately fitting dentures.

“The resulting tightness of the lips and oral musculature leads to difficulty in placing teeth in the neutral zone- that is, a zone where there is equality of pressure acting on the polish surfaces of the denture.” (Full Dentures (1971) – Alan Mack pg 11)

[edit] Aesthetics

As noted above a collapse in facial structure leads to a deteriation of facial aesthetics. The way we outwardly present ourselves is important to most people and an absence of a denture is clearly visible to others. So to the endentulous person aesthetics is probably the most important issue to be resolved when a person becomes edentulous, as more time passes the face continues to shrink and aesthetics gets worse, so avoiding the dentist makes matters worse. The normal reaction to being edentulous is to try and hide it, most people are very conscious of the way they look and the effects mentioned earlier will have an impact on anyone with this condition. This can be from covering the mouth with the hand, to more extreme cases such as avoiding social events. Eating and drinking also pose an aesthetic problem, as food and drink can dribble, obviously embarrassing.

[edit] Tempero-Mandibular Joint

Medically, when a person goes from the state of being fully dentate to that of toothless there is a void that has been created inside the oral cavity, this contributes towards a diminished combination of pressures, onto the temporal-mandibular joint(TM). These “pressures” would normally be transmitted from the teeth and onto the alveolar ridges and mandible, instead these masticatory forces are absent. A lack of teeth means the mouth can close further than is within normal limits, until upper and lower alveolar ridges meet. In the short term this does not pose a problem, however, if allowed to go untreated for a long period of time the tendons and ligaments of the TM joint and of mastication will, under these new environmental conditions, morph shape in order to meet the new oral configuration. This transfiguration occurs gradually causing no physical discomfort to the patient, a great contributor to attention not being sought. Problems occur when the patient decides to be fitted with dentures, the mouth will be subjected to a varying vertical dimension, stretching the concerned tendons, ligaments and muscles. This will cause severe discomfort to the patient, with mastication causing pain due to extra stress now being relayed onto the TM joint, resulting in inflammation and more suffering. If this edentulous state has progressed too far it is possible that whilst treatment would proceed it is quite possible it would ultimately end up in failure, i.e. removal of the denture, due to the obstacles being too great to overcome.

[edit] Speech

The teeth play a major role in the mouth during speech. When we pronounce different words our mouth and tongue move in a different way, often making contact with the teeth in order to make different sounds and words. This is especially the case with the anterior teeth. These act as a surface for the tip on the tongue to touch and strike, making sounds like “la” and “th”. The teeth are also important with respect for support of the lips. This support allows the lips to glide over the surface of the teeth in order to make different shapes with the lips and mouth, again to produce different sounds. Our edentulous patient has no anterior teeth so has trouble with the aforementioned sounds, resulting in a slight lisp. The patient also has trouble pronouncing “r’s” “p’s” and “w’s” amongst others. This is due to a lack of support for the lips which cannot move as accurately and cannot glide into as many positions. This results in slight speech defects varying in severity from patient to patient. The teeth in the mouth have their roots buried into structures known as alveolar ridges which are present on the maxilla and the mandible. These structures are essentially the supporting structures for the teeth and make up a sizable portion of the vertical dimension. When a person becomes edentulous these ridges begin to resorb, shrinking in size and hastened by the repair of the alveolar ridges after extraction.

"In the edentulous mouth, resorption of the residual ridge is a continuing process, which manifests itself through anatomical changes.” (Atwood, 1971; Tallgren, 1972)

[edit] Ridge Resorption

There is a variety of ridge types throughout the edentulous community. “The ‘normal’ ridge is smoothly contoured and moulded, offering good resistance to the lateral forces of mastication.” (Mack, 1971)

There is a ‘flat’ or resorbed ridge, this means that there is little structure for the dentures to sit and secure to. Lateral forces can cause the denture to become unstable and move out of position, this can make eating certain things very difficult and sometimes impossible.

“Narrow, sharp, or V-shaped ridges offer poor support for the vertical pressures placed on them by the masticatory load.” (Mack, 1971)

A sharp fibrous ridge can buckle under pressure if a large force is placed onto the denture, e.g. during mastication. This would be very painful for the patient and could result in an alveolectomy to remove excess or damages tissue in order to relieve pain and to improve denture wearing comfort, a sharp bony ridge could also fracture at the tip, again extremely painful in reality as both bone and tissue are broken. Impression techniques can be implemented to try to avoid such occurrences, this will make the denture more comfortable and provide some protection to the affected ridge. The final ridge type we come to is that of the prominent bulbous or undercut ridges. If this type is too severe and is present on both sides of the maxilla or mandible, then treatment of the patient by the dentist has to cease until surgery has been performed to repair the ridges so that dentures can be fitted.

[edit] Masticatory Efficiency

The final area of discussion is probably the most important of all, physiologically. The main function of our teeth is to allow us to masticate food thoroughly, working in saliva to aid digestion, in order so it can be formed into a bolus, pushed to the back of the throat and swallowed. After four to five years of endentulism, it becomes impossible for the afflicted to chew food normally, in such cases, if the patient wanted to continue with their regular diet, then they would have to mash their food up first. Some people will not want to do this and will instead eat things which are naturally soft and unabrasive.

“Harder and more coarse foods such as fruits, vegetables and meats, which are typically major sources of vitamins, minerals and proteins, come to be regarded as either difficult or nearly impossible to chew. Consequently, a tendency to favour softer, more processed foods develops.” (Hutton, Feine, Morais, 2002)

As a consequence of this lack of certain nutrition, various problems can occur, from the mild to the extreme. Lack of certain vitamins (A, E and C) and low levels of riboflavin and thyamin can produce a variety of conditions, ranging from constipation, weight loss, arthritis and rheumatism. There are more serious conditions such as heart disease and Parkinson’s disease and even to the extreme, certain types of Cancer.

“Numerous studies linking edentulism with instances of disease and medical conditions have been reported. In a cross-sectional study, Hamasha and others found significant differences between edentulous and dentate individuals with respect to rates of atherosclerotic vascular disease, heart failure, ischemic heart disease and joint disease.” (Hutton, Feine, Morais, 2002).

Elderly edentulous patients are most prone to nutritional problems and contribute towards infirmity due to osteoporosis and reduced muscle tone.

[edit] Bibliography

Full Dentures – A Dental Practitioners Handbook (1971) – Alan Mack

Prosthodontics – Principles and Management Strategies (1996) – Owall B., Kayser A. F., Carlsson G. E.

Clinical Dental Prosthetics – Third Edition (1989) – Macgregor A. R.

Is There an Association Between Edentulism and Nutritional State? (March 2002, Vol. 68, No. 3) - Brian Hutton, BSc, Jocelyne Feine, DDS, HDR, José Morais, MD, FRCPC, CSPG - Journal of the Canadian Dental Association (http://www.cda-adc.ca/jcda/vol-68/issue-3/182.pdf)