Toothlessness or edentulism is the condition of having no teeth. In organisms that naturally have teeth, it is the result of tooth loss. Organisms that never possessed teeth can also be described as edentulous. Examples are the members of the former zoological classification order of Edentata, which included anteaters and sloths, as they possess no anterior teeth and no or poorly developed posterior teeth.
In naturally dentate species, edentulism is more than just the simple presence or absence of teeth. It is biochemically complex because the teeth, jaws, and oral mucosa are dynamic. Processes such as bone remodeling (loss and gain of bone tissue) in the jaws and inflammation of soft tissue in response to the oral microbiota are clinically important for edentulous people. For example, bone resorption in the jaw is frequently how the teeth were able to detach in the first place. The jaw in an edentulous area undergoes further resorption even after the teeth are gone; and the insertion of dental implants can elicit new bone formation, leading to osseointegration. Meanwhile, bacteria and yeasts of the oral cavity and the immune system of their host create an immensely complicated and constantly changing interplay that presents clinically as gingivitis, caries, stomatitis, and other periodontal pathology.
Signs and symptoms
For people, the relevance and functionality of teeth can be easily taken for granted, but a closer examination of their considerable significance will demonstrate how they are actually very important. Among other things, teeth serve to:
support the lips and cheeks, providing for a fuller, more aesthetically pleasing appearance
Tooth loss also has a psychological impact: it has been shown to generally lower a patient's quality of life, with this compromised oral function leading to decreased self-esteem and a decline in psychological well-being. Patients may be embarrassed to smile, eat and talk.[1]
Facial support and aesthetics
When an individual's mouth is at rest, the teeth in the opposing jaws are nearly touching; there is what is referred to as a "freeway space" of roughly 2–3mm. However, this distance is partially maintained as a result of the teeth limiting any further closure past the point of maximum intercuspidation. When there are no teeth present in the mouth, the natural vertical dimension of occlusion is lost and the mouth has a tendency to overclose. This causes the cheeks to exhibit a "sunken-in" appearance and wrinkle lines to form at the commissures. Additionally, the anterior teeth, when present, serve to properly support the lips and provide for certain aesthetic features, such as an acute nasiolabial angle. Loss of muscle tone and skin elasticity due to old age, when most individuals begin to experience edentulism, tend to further exacerbate this condition.
The tongue, which consists of a very dynamic group of muscles, tends to fill the space it is allowed, and in the absence of teeth, will broaden out.[2] This makes it initially difficult to fabricate both complete dentures and removable partial dentures for patients exhibiting complete and partial edentulism, respectively; however, once the space is "taken back" by the prosthetic teeth, the tongue will return to a narrower body.
Vertical dimension of occlusion
As stated, the position of maximal closure in the presence of teeth is referred to as maximum intercuspidation, and the vertical jaw relationship in this position is referred to as the vertical dimension of occlusion. With the loss of teeth, there is a decrease in this vertical dimension, as the mouth is allowed to overclose when there are no teeth present to block the further upward movement of the mandible towards the maxilla. This may contribute, as explained above, to a sunken-in appearance of the cheeks, because there is now "too much" cheek than is needed to extend from the maxilla to the mandible when in an over closed position. If this situation is left untreated for many years, the muscles and tendons of the mandible and the TMJ may manifest with altered tone and elasticity.
Pronunciation
The teeth play a major role in speech. Some letter sounds require the lips and/or tongue to make contact with teeth for proper pronunciation of the sound, and lack of teeth will obviously affect the way in which an edentulous individual can pronounce these sounds.
For example, the consonant sounds of the English languages, z, j, and x are achieved with tooth-to-tooth contact; d, n, l, t, and th are achieved with tongue-to-tooth contact; the fricatives f and v are achieved through lip-to-tooth contact. The edentulous individual finds these sounds very difficult to enunciate properly.
The green line indicates the faciolingual dimensions of a newly edentulous ridge, while the blue line indicates these dimensions after the occurrence of very severe resorption.
The alveolar ridges are columns of bone that surround and anchor the teeth and run the entire length, mesiodistally, of both the maxillary and mandibular dental arches. The alveolar bone is unique in that it exists for the sake of the teeth that it retains; when the teeth are absent, the bone slowly resorbs. The maxilla resorbs in a superioposterior direction, and the mandible resorbs in an inferioanterior direction, thus eventually converting an individual's occlusal scheme from a Class I to a Class III. Loss of teeth alters the form of the alveolar bone in 91% of cases.[3]
In addition to this resorption of bone in the vertical and anterioposterior dimensions, the alveolus also resorbs faciolingually, thus diminishing the width of the ridge. What initially began as a tall bell curve (in the faciolingual dimension) eventually becomes much shorter and broader. Resorption is exacerbated by pressure on the bone; thus, long-term complete denture wearers will experience more drastic reductions to their ridges than non-denture wearers. Those individuals who do wear dentures can decrease the amount of bone loss by retaining some tooth roots in the form of overdenture abutments or have implants placed. Note that the depiction above shows a very excessive change and that this many take many years of denture wear to achieve.
Ridge resorption may also alter the form of the ridges to less predictable shapes, such as bulbous ridges with undercuts or even sharp, thin, knife-edged ridges, depending on the many possible factors that influenced the resorption.
Bone loss with missing teeth, partials and complete dentures is progressive. According to Wolff's law, bone is stimulated, strengthened and continually renewed directly by a tooth or an implant. Teeth and implants provide this direct stimulation which develops stronger bone around them.
A 1970 research study of 1012 patients by Jozewicz showed denture wearers had a significantly higher rate of bone loss.[citation needed] Tallgren's 25-year study in 1972 also showed denture wearers have continued bone loss over the years.[citation needed] The biting force on the gum tissue irritates the bone and it melts away with a decrease in volume and density. Carlsson's 1967 study showed a dramatic bone loss during the first year after a tooth extraction which continues over the years, even without a denture or partial on it.[citation needed]
Effects on jawline and facial structure due to complete edentulism
The longer people are missing teeth, wear dentures or partials, the less bone they have in their jaws. This may result in decreased ability to chew food well, a decreased quality of life, social insecurity and decreasing esthetics because of a collapsing of the lower third of their face.
The bone loss also results in a significant decrease in chewing force, prompting many denture and partial wearers to avoid certain kinds of food. Food collecting under the appliance takes their enjoyment out of eating so they make their grocery and restaurant choices by what they can eat. There are several reports that correlate the quality and length of peoples lives with their ability to chew.[citation needed]
Dental implant studies from 1977 by Branemark and countless others show dental implants stop this progressive loss and stabilize the bone over the long term.[citation needed] Implanted teeth provide a stable, effective tooth replacement that feels natural. They also provide an improved ability to chew comfortably and for those missing many teeth an improved sense of well being. Dental implants have become the standard for replacing missing teeth in dentistry.
Masticatory efficiency
Physiologically, teeth provide for greater chewing ability. They allow us to masticate food thoroughly, increasing the surface area necessary to allow for the enzymes present in the saliva, as well as in the stomach and intestines, to digest our food. Chewing also allows food to be prepared into small boli that are more readily swallowed than haphazard chunks of considerable size. For those who are even partially endentulous, it may become extremely difficult to chew food efficiently enough to swallow comfortably, although this is entirely dependent upon which teeth are lost. When an individual loses enough posterior teeth to make it difficult to chew, he or she may need to cut their food into very small pieces and learn how to make use of their anterior teeth to chew. If enough posterior teeth are missing, this will not only affect their chewing abilities, but also their occlusion; posterior teeth, in a mutually protected occlusion, help to protect the anterior teeth and the vertical dimension of occlusion and, when missing, the anterior teeth begin to bear a greater amount of force than they are structurally prepared for. Thus, loss of posterior teeth will cause the anterior teeth to splay. This can be prevented by obtaining dental prostheses, such as removable partial dentures, bridges or implant-supported crowns. In addition to reestablishing a protected occlusion, these prostheses can greatly improve one's chewing abilities.
As a consequence of a lack of certain nutrition due to altered eating habits, various health problems can occur, from the mild to the extreme. Lack of certain vitamins (A, E and C) and low levels of riboflavin and thiamin 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. Treatments include changing approaches to eating such as cutting food in advance to make eating easier and less likely to avoid as well as consumer health products such as multivitamins and multi-minerals specifically designed to support the nutritional issues experienced by denture wearers.[citation needed]
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.[4]
Cause
Edentulism is a condition which can have multiple causes. In exceedingly rare cases, toothlessness may result from the teeth not developing in the first place (anodontia).[5] However, in most cases it is as a result of permanent tooth extraction in adulthood.[5] This may or may not be due to dental caries, periodontal disease (gum disease), trauma or other pathology of the face and mouth (i.e. cysts, tumours).[5] In those under 45 years of age, dental caries is considered to be the main cause of toothlessness, whereas periodontal disease is the primary cause of tooth loss in older age groups.[6]
Replacing missing teeth
There are three main ways in which missing teeth can be replaced:
Bridges: Used to replace one or more missing teeth. False teeth are supported by the remaining, adjacent natural teeth.
Advantages:
They are fixed, they do not require removal on a frequent basis. Therefore, they are easily maintained.
Can be cleaned by normal brushing procedures.
Unlike dentures, they do not require skill in their use. They will not move about.[7]
Disadvantages:
They generally require the preparation of adjacent teeth. This is destructive and not required for the placement of a denture.
They have a higher rate of failure than either Dentures or Implants.[7]
Dentures: False teeth are mounted onto an acrylic base. These may be partial (to replace some missing teeth) or complete (where all the natural teeth are missing).[8] Dentures may be removable, or fixed in the mouth by dental implants.
Advantages:
This is the least expensive option for the replacement of teeth.
The least invasive, no surgery needed (usually).
Disadvantages:
Quite often rely solely on the mucosa for support, do not tend to be as stable as the other options.
Very difficult to keep clean and can exacerbate any oral hygiene issues.
They are difficult to learn to use. Quite often require complex muscular control to hold them in place.
Not as efficient as other options. Foods such as apples and nuts will often have to be avoided.[citation needed]
Dental Implants: To replace a single tooth, a screw (the implant) is placed into the jaw bone, which a false tooth is screwed onto. Implants can also be used to support bridges or dentures.[9]
Advantages:
They are much more realistic than the other options. They have similar efficiency and aesthetics to an actual tooth.
They do not require the destruction of the adjacent teeth like bridges.
They last 5-8 times longer than both bridges and dentures. Despite the initial higher cost, it pays off in the long term.
Much easier to maintain, with oral hygiene procedures being rather similar to an actual tooth.[citation needed]
Disadvantages:
Cost: they are very expensive. A single implant will cost between £2000-3000 on average.
Surgery: Their placement requires quite invasive surgery. With surgery comes risks (e.g. infection, swelling, bleeding).[citation needed]
Replacement: The actual implant itself rarely requires replacement, but the actual abutment, or tooth sitting on top of the implant will. This needs replacing on average every 10–15 years.
Time: Once an implant has been placed, the tooth replacement does not occur immediately. Implants take time for bone integration. The majority require 3 to 6 months before the final restoration is placed.[citation needed]
Clinical classification
A classification system has been developed by the American College of Prosthodontists. The classification are based on diagnostic findings, which is used to help practitioners determine appropriate treatments for patients.
The diagnostic criteria used to classify edentulism are:
There are four categories which are Class I, II, III and IV.
Class I: Minimally compromised
This class is most likely to be successfully treated with complete dentures. The characteristics include:
Residual bone height of 21mm or more measured at the lowest vertical height of the mandible shown on a panoramic radiograph.
Residual ridge morphology resists horizontal and vertical movement of the denture base
Location of muscle attachments that arc conducive to denture base stability and retention
Class I maxillomandibular relationship.
Class II: Moderately compromised
This class is distinguished by the continued degradation of the denture‐supporting anatomy. It is also characterised by specific patient management and lifestyle considerations as well as systemic disease interactions. Characteristics include:
Residual bone height of 16 to 20mrn measured at the lowest vertical height of the mandible on a panoramic radiograph.
Residual ridge morphology that does not show horizontal and vertical movement of the denture base.
Location of muscle attachments with limited influence on denture base stability and retention.
Class I maxillomandibular relationship.
Minor modifiers, psychosocial considerations, mild systemic disease with oral manifestation.
Class III: Substantially compromised
This classification level is where surgical revision of supporting structures is needed to allow for adequate prosthodontic function.
Residual alveolar bone height of 11 to 15mm measured at the least vertical height of the mandible on a panoramic radiograph.
Residual ridge morphology has minimum influence to resist horizontal or vertical movement of the denture base.
Location of muscle attachments with moderate influence on denture base stability and retention.
Class I, II or III maxillomandibular relationship.
The conditions that need preprosthetic surgery include:
minor soft tissue procedures
minor hard tissue procedures including alveoloplasty
simple implant placement, no augmentation required
multiple extractions leading to complete edentulism for immediate denture placement.
Class IV: Severely compromised
This classification level depicts the most debilitated edentulous condition. Surgical reconstruction is almost always indicated but cannot always be accomplished because of the patient's health, preferences, dental history, and financial considerations. When surgical revision is not an option, prosthodontic techniques of a specialized nature must be used to achieve an adequate treatment outcome.
Residual vertical bone height of 10mm or less measured at the least vertical height of the mandible on a panoramic radiograph.
Residual ridge offers no resistance to horizontal or vertical movement.
Muscle attachment location that can be expected to have significant influence on denture base stability and retention.
Class I, II, or III maxillomandibular relationships.
History of paresthesia or dysesthesia.
Major conditions requiring preprosthetic surgery
complex implant placement, augmentation required
surgical correction of dentofacial deformities
hard tissue augmentation required
major soft tissue revision required, i.e., vestibular extensions with or without soft tissue grafting.[10]
Edentulism affects approximately 158million people globally as of 2010 (2.3% of the population).[12] It is more common in women at 2.7% compared to the male rate of 1.9%.[12]
A cross-sectional analysis of data from the Survey of Health, Ageing and Retirement in Europe (SHARE) from 14 European countries (Austria, Belgium, Czech Republic, Denmark, Estonia, France, Germany, Italy, Luxembourg, the Netherlands, Slovenia, Spain, Sweden, and Switzerland) and Israel showed substantial variation in the age-standardized mean numbers of natural teeth amongst people aged 50 years and older, ranging from 14.3 teeth (Estonia) to 24.5 teeth (Sweden). The oral health goal of retaining at least 20 teeth at age 80 years was achieved by 25% of the population or less in most countries. A target concerning edentulism (≤15% in population aged 65–74 years) was reached in Sweden, Switzerland, Denmark, France, and Germany. Tooth replacement practices varied especially for a number of up to five missing teeth which were more likely to be replaced in Austria, Germany, Luxembourg, and Switzerland than in Israel, Denmark, Estonia, Spain, and Sweden.[13]
The prevalence of Kennedy Class III partial denture was predominant among younger population of 21-30 year and 31–40 years, whereas in group III between 41 and 50 years Class I was predominant. It can be stated that the need for prosthodontics care is expected to increase with age, and hence, more efforts should be made for improving dental education and motivation among patients.[14]
Edentulism occurs more often in people from the lower end of the socioeconomic scale.[15][16][17]
Society and culture
It is estimated that tooth loss results in worldwide productivity losses in the size of about US$63 billion yearly.[18]
Related Research Articles
Human teeth function to mechanically break down items of food by cutting and crushing them in preparation for swallowing and digesting. As such, they are considered part of the human digestive system. Humans have four types of teeth: incisors, canines, premolars, and molars, which each have a specific function. The incisors cut the food, the canines tear the food and the molars and premolars crush the food. The roots of teeth are embedded in the maxilla or the mandible and are covered by gums. Teeth are made of multiple tissues of varying density and hardness.
Dentures are prosthetic devices constructed to replace missing teeth, supported by the surrounding soft and hard tissues of the oral cavity. Conventional dentures are removable. However, there are many denture designs, some of which rely on bonding or clasping onto teeth or dental implants. There are two main categories of dentures, the distinction being whether they fit onto the mandibular arch or on the maxillary arch.
A bridge is a fixed dental restoration used to replace one or more missing teeth by joining an artificial tooth definitively to adjacent teeth or dental implants.
A dental technician is a member of the dental team who, upon prescription from a dental clinician, constructs custom-made restorative and dental appliances.
A dental implant is a prosthesis that interfaces with the bone of the jaw or skull to support a dental prosthesis such as a crown, bridge, denture, or facial prosthesis or to act as an orthodontic anchor. The basis for modern dental implants is a biological process called osseointegration, in which materials such as titanium or zirconia form an intimate bond to the bone. The implant fixture is first placed so that it is likely to osseointegrate, then a dental prosthetic is added. A variable amount of healing time is required for osseointegration before either the dental prosthetic is attached to the implant or an abutment is placed which will hold a dental prosthetic/crown.
A removable partial denture (RPD) is a denture for a partially edentulous patient who desires to have replacement teeth for functional or aesthetic reasons and who cannot have a bridge for any reason, such as a lack of required teeth to serve as support for a bridge or financial limitations.
Geriatric dentistry is the delivery of dental care to older adults involving diagnosis, prevention, management and treatment of problems associated with age related diseases. The mouth is referred to as a mirror of overall health, reinforcing that oral health is an integral part of general health. In the elderly population poor oral health has been considered a risk factor for general health problems. Older adults are more susceptible to oral conditions or diseases due to an increase in chronic conditions and physical/mental disabilities. Thus, the elderly form a distinct group in terms of provision of care.
The alveolar process or alveolar bone is the thickened ridge of bone that contains the tooth sockets on the jaw bones. The structures are covered by gums as part of the oral cavity.
A dental emergency is an issue involving the teeth and supporting tissues that are of high importance to be treated by the relevant professional. Dental emergencies do not always involve pain, although this is a common signal that something needs to be looked at. Pain can originate from the tooth, surrounding tissues or can have the sensation of originating in the teeth but be caused by an independent source. Depending on the type of pain experienced an experienced clinician can determine the likely cause and can treat the issue as each tissue type gives different messages in a dental emergency.
Anodontia is a rare genetic disorder characterized by the congenital absence of all primary or permanent teeth. It is divided into two subsections, complete absence of teeth or only some absence of teeth. It is associated with the group of skin and nerve syndromes called the ectodermal dysplasias. Anodontia is usually part of a syndrome and seldom occurs as an isolated entity. There is usually no exact cause for anodontia. The defect results in the dental lamina obstruction during embryogenesis due to local, systemic and genetic factors.
Tooth loss is a process in which one or more teeth come loose and fall out. Tooth loss is normal for deciduous teeth, when they are replaced by a person's adult teeth. Otherwise, losing teeth is undesirable and is the result of injury or disease, such as dental avulsion, tooth decay, and gum disease. The condition of being toothless or missing one or more teeth is called edentulism. Tooth loss has been shown to causally reduce overall health and wellbeing as it increases the probability of depression.
Occlusal trauma is the damage to teeth when an excessive force is acted upon them and they do not align properly.
Socket preservation or alveolar ridge preservation is a procedure to reduce bone loss after tooth extraction. After tooth extraction, the jaw bone has a natural tendency to become narrow, and lose its original shape because the bone quickly resorbs, resulting in 30–60% loss in bone volume in the first six months. Bone loss, can compromise the ability to place a dental implant, or its aesthetics and functional ability.
In dentistry, overeruption is the physiological movement of a tooth lacking an opposing partner in the dental occlusion. Because of the lack of opposing force and the natural eruptive potential of the tooth there is a tendency for the tooth to erupt out of the line of the occlusion.
The term All-on-4, also known as All‐on‐Four and All‐in‐Four, refers to 'all' teeth being supported 'on four' dental implants, a prosthodontics procedure for total rehabilitation of the edentulous (toothless) patient, or for patients with badly broken down teeth, decayed teeth, or compromised teeth due to gum disease. It consists of the rehabilitation of either edentulous or dentate maxilla and / or mandible with fixed prosthesis by placing four implants in the anterior maxilla, where bone density is higher. The four implants support a fixed prosthesis with 10 to 14 teeth, and it is placed immediately, typically within 24 hours of surgery.
Tooth ankylosis refers to a fusion between a tooth and underlying bony support tissues. In some species, this is a normal process that occurs during the formation or maintenance of the dentition. By contrast, in humans tooth ankylosis is pathological, whereby a fusion between alveolar bone and the cementum of a tooth occurs.
Alveoloplasty is a surgical pre-prosthetic procedure performed to facilitate removal of teeth, and smoothen or reshape the jawbone for prosthetic and cosmetic purposes. In this procedure, the bony edges of the alveolar ridge and its surrounding structures is made smooth, redesigned or recontoured so that a well-fitting, comfortable, and esthetic prosthesis may be fabricated or implants may be surgically inserted. This pre-prosthetic surgery which may include bone grafting prepares the mouth to receive a prosthesis or implants by improving the condition and quality of the supporting structures so they can provide support, better retention and stability to the prosthesis.
A complete denture is a removable appliance used when all teeth within a jaw have been lost and need to be prosthetically replaced. In contrast to a partial denture, a complete denture is constructed when there are no more teeth left in an arch, hence it is an exclusively tissue-supported prosthesis. A complete denture can be opposed by natural dentition, a partial or complete denture, fixed appliances or, sometimes, soft tissues.
Overdenture is any removable dental prosthesis that covers and rests on one or more remaining natural teeth, the roots of natural teeth, and/or dental implants. It is one of the most practical measures used in preventive dentistry. Overdentures can be either tooth supported or implant supported. It is found to help in the preservation of alveolar bone and delay the process of complete edentulism.
Occlusion according to The Glossary of Prosthodontic Terms Ninth Edition is defined as "the static relationship between the incising or masticating surfaces of the maxillary or mandibular teeth or tooth analogues".
↑ Mack A (1971). Full Dentures. Bristol: Wright. p.11. ISBN978-0723602996. 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
↑ Abrams H, Kopczyk RA, Kaplan AL (February 1987). "Incidence of anterior ridge deformities in partially edentulous patients". The Journal of Prosthetic Dentistry. 57 (2): 191–4. doi:10.1016/0022-3913(87)90145-4. PMID3470510.
1 2 3 Jahangiri, L., Choi, M., Moghadam, M. and Jawad, S. (2015). Interventions for missing teeth: Removable prostheses for the edentulous mandible. Cochrane Database of Systematic Reviews, (2).
↑ Papapanou, P. N. Periodontal diseases: epidemiology. Annals of periodontology/the American Academy of Periodontology 1, 1–36, doi: 10.1902/annals.1996.1.1.1 (1996).
↑ American Dental Association (ADA) Division of Science (June 2015). "FOR THE PATIENT. Bridges, implants, and dentures". Journal of the American Dental Association. 146 (6): 490. doi:10.1016/j.adaj.2015.04.004. PMID26025833.
↑ McGarry, Thomas J.; Nimmo, Arthur; Skiba, James F.; Ahlstrom, Robert H.; Smith, Christopher R.; Koumjian, Jack H.; Arbree, Nancy S. (2002). "Classification system for partial edentulism". Journal of Prosthodontics. 11 (3): 181–193. doi:10.1053/jopr.2002.126094. ISSN1532-849X. PMID12237799. S2CID41908478.
↑ Stock C, Jürges H, Shen J, Bozorgmehr K, Listl S (June 2016). "A comparison of tooth retention and replacement across 15 countries in the over-50s". Community Dentistry and Oral Epidemiology. 44 (3): 223–31. doi:10.1111/cdoe.12209. PMID26706945.
↑ Matsuyama Y, Jürges H, Listl S (January 2019). "The Causal Effect of Education on Tooth Loss: Evidence From United Kingdom Schooling Reforms". American Journal of Epidemiology. 188 (1): 87–95. doi:10.1093/aje/kwy205. PMID30203091.
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