Regressive Alterations of Teeth l Oral pathology MCQ

 

Regressive Alterations of Teeth (abrasion , physiologic and pathological attrition , erosion and tooth resorption l Oral pathology MCQ for dental students

Regressive Alterations of Teeth

• Regressive alterations are the group of retrogressive changes in the teeth, which occur

• due to non-bacterial causes and results in wear and tear of the tooth structures with impairment of function.

• Some of these regressive changes in teeth result from generalized ageing process and others occur due to chronic persistent tissue injury.

ATTRITION

• Attrition is a constant form of retrogressive change in teeth, characterized by wear of tooth substance or restoration as a result of tooth - to–tooth contact during mastication or parafunction.
• It is an age related process and older individuals often exhibit more attrition in their teeth as compared to the young.
• The rate and severity of attrition depends upon several factors such as: Diet quality, dentition, force of the masticatory muscles and chewing habits, etc.

Types of Attrition

• Although clinical distinction is difficult to make, attrition may be divided into two types:

1. Physiological attrition
2. Pathological attrition

Physiological Attrition

• The tooth loss in physiological attrition is fairly constant and is proportionate to the age of the individual.

• Physiological attrition begins with wearing of the incisal edge of incisors; it is followed by the palatal cusp of maxillary molars and buccal cusp of mandibular molars.

• Attrition also occurs in the proximal surfaces of teeth in the contact point areas.

Pathological Attrition

• Pathological attrition occurs due to certain abnormalities in occlusion, chewing pattern or due to some structural defects in the teeth.

• The tooth wear in this type of attrition does not maintain a consistant pattern and the amount of tooth loss is not proportionate to the age of the individual.

Causes of Pathological attrition

1. Abnormal occlusion May be developmental, e.g. crowding of teeth or malposed teeth. In these cases abnormal occlusal positioning of teeth many lead to traumatic contact during chewing which may lead to more tooth wear.
2. May be acquired, e.g. extraction of teeth, extraction of some teeth from the dental arch
3. will increase the occlusal load on the remaining teeth as the chewing force for the individual remains constant.
4. Abnormal chewing habits Para-functional chewing habits, e.g. Bruxism (habitual grinding of teeth) and chronic persistent chewing of coarse and abrasive foods or other substance, e.g. tobacco and betel nut, etc.
5. Structural defects in teeth : Amelogenesis imperfect and Dentinogenesis imperfect . In these situations, the hardness of enamel or dentin is much more inferior as compared to the normal teeth and therefore, the rate of tooth wear is high even in normal chewing pressures.

Clinical Features of Attrition

1. Attrition of tooth is clinically manifested by the formation of well-polished facets on the tip of the cusps, incisal edges and on the proximal contact areas of the teeth.
2. In advanced cases, attrition may lead to severe reduction in the cuspal height with complete wearing of enamel and flattening of the occlusal surface.
3. When dentin becomes exposed it generally becomes discolored brown.
4. When the enamel is lost on the occlusal surface, the dentin becomes attrited at a faster rate and the lesion may become cap shaped, surrounded by a rim of enamel at the periphery.
5. Attrition in the proximal surfaces of teeth causes transformation of proximal “contact points” to relatively broader “ contact areas” and it may even lead to mesial migration of
6. the teeth in the dental arch.
7. Normally men often show more severe attritions of teeth than women.
8. Exposure of dentinal tubules in severe cases of attrition may lead to hypersensitivity.
9. On some occasions, attrition may even result in pulp exposure.
10. Attrition may also occur on the restorations of teeth. A common example in this regard, is the development of shiny facets on the amalgam filled surfaces.
11. Attrition may even possibly lead to fracture of the cusps of teeth or restorations.

Treatment of attrition :

• Treatment of attrition is difficult, however certain things can be done to reduce further tooth wear.

1. Corrections of developmental abnormalities causing traumatic occlusion.
2. Correction of Para functional chewing habits.
3. Protection of tooth by metal or metal–ceramic crowns where structural defects (e.g. Amelogenesis or dentinogenesis imperfecta) exit.
4. Construction of occlusal guard if bruxism habit is persisting.

ABRASION

• Abrasion is the pathological wearing of dental tissues by friction with the foreign substances independent of occlusion.

Etiology and Pathogenesis

• Different foreign substances produce different patterns of tooth abrasion. However, the process of tooth wear is similar in every case.

Toothbrush Abrasion

• It is the most common type of abrasion and is mostly associated with faulty tooth brushing technique.

• Abrasion occurs when the tooth brushing is done in a horizontal rather than a vertical direction and excessive force is applied during brushing.

• The condition is made even worse when an abrasive dentifrice is used.

Habitual Abrasion

• Habitual pipe smokers may develop abrasion on the incisal edges of upper and lower anterior teeth.

• Improper and habitual use of tooth prick or dental floss, etc. can cause abrasions on the proximal surfaces of teeth.

Occupational Abrasions

• Occupational abrasion develops when objects or instruments are habitually held between the teeth by people during work.

• Hairdressers often grip the hairpins between their teeth during work and this can cause tooth abrasions.

• Carpenters often keep small tools or nails between their teeth when they are at work and this type of practice cause notching on the tooth surface especially at the incisal edges of the anterior teeth.

• Similar occupational abrasions can also be seen among tailors and shoemakers.

Abrasions by Prosthetic Appliances

• Faulty clasp design in removable partial denture prosthesis may also cause abrasion of tooth.

Ritual Abrasions

• Ritual abrasions of tooth are uncommon nowadays and is mainly confined in Africa.

• For example ancient people used to believe in some pragmatic concepts and according to that they often used to mutilate their teeth with some instruments.

• These practices were aimed at making themselves immune from evil spirits.

Clinical Features of Abrasions

1. In abrasion of tooth, the type and severity of surface wear will depend upon the duration and the type of faulty habit adopted by the person.
2. Clinical manifestations differ in different types of habit, for example a defect in the tooth due to toothbrush abrasion will differ from that of the occupational abrasion or from the habitual abrasion.
3. Toothbrush abrasions commonly occur in the cervical regions of the labial surfaces of
4. incisors, canines and premolars.
5. Teeth on the left side of the arch are more severely involved in right-handed persons and vice-versa.
6. Maxillary teeth are more commonly affected than mandibular teeth.
7. The abrasion produces a ‘v’ shaped or wedge shaped grove on the tooth with sharp angles and highly polished dentine surfaces.
8. In cervical abrasion, lesions are more often wide than deep.
9. Toothbrush abrasion may also cause gingival recession.
10. In pipe smokers, abrasion develops on the insical surfaces of upper and lower anterior teeth. The lesion is characterized by a wellpolished notch, whose shape typically
11. matches with the shape of the pipe stem used by the smoker.
12. Abrasion caused by habitual holding of nails or needles or other small tools by the tailors or shoe makers or carpenters, etc. often produces a small, deep, well polished ‘ditch’ on the incisal edge of teeth.
13. Severe abrasion (of any type) may cause opening up of the dentinal tubules and therefore the patient may experience sensitivity in the affected teeth due to hot and cold substances.
14. Secondary or reactionary dentin usually forms on the pulpal surfaces to protect the teeth from pulp exposures.
15. In untreated cases, the lesion may deepen further and it may eventually expose the dental pulp with subsequent of pulpitis and other associated manifestations.

Treatment of abrasions

• Avoidance of abnormal brushing habits prevent abrasions, however in already developed cases, restorative treatment helps to keep the tooth surface intact and also it prevents further tooth wear.

EROSION

• Erosion can be defined as progressive irreversible loss of hard dental tissues by some chemical process that does not involve bacterial action.

• In erosion, dissolution of the mineralized tooth structure occurs upon contact with acids, which are introduced into the oral cavity either from intrinsic sources or from extrinsic sources.

• However, it is important to note that erosion may render the teeth more susceptible to other retrogressive changes like attrition and abrasion, etc.

Extrinsic Factors for Erosion

• Acidic Foods and Beverages
• Acids from extrinsic sources (source is outside the body), which can cause erosion of tooth usually, come from acidic beverages, foods, and medications, etc. or from the environment itself.

1. Most of the fruits and fruits juices have a low pH and these can cause erosion of tooth if consumed regularly.
2. Carbonated soft drinks and sports drinks are also very acidic in nature and frequent consumption of these drinks may result in erosion of tooth.
3. Rate of erosion of tooth is proportional to the amount and frequency of consumption of acidic beverages/foods.
4. Erosive potential of acidic foods/beverages can be reduced if
5. They contain large amount of calcium, phosphate and fluoride, etc. which help in tooth remineralization.
6. If tooth brushing is done after every intake of beverage.
7. If drinks are taken by a straw rather than from a glass (it minimizes contact time).

Medications

• Some medicines can be highly acidic in nature (e.g. Vitamin C and Hydrochloric acid preparations etc) and they can cause erosion of teeth when chewed or kept in the mouth for a long time prior to swallowing.

Occupational Erosions

• Occupational erosions are seen among workers who often come in contact with acids at their place of work.

• Commonly vapors of different acids, e.g. chromic acid, hydrochloric acid, sulphuric acid and nitric acids, etc. are released into the work environment during industrial electrolyte process.

• These vapors can cause erosion of teeth, on those surfaces, which are normally exposed to the atmosphere (incisal third of incisors).

• Commonly the workers involved in manufacturing of lead acid batteries or sanitary cleansers or soft drinks etc. or those who are working in galvanizing or plating factories often develop occupational erosions of teeth.

• Occupational wine tasters often have erosion in their teeth.

• Swimmers who practice regularly in the pools can have erosion of their teeth if the pool water contains higher concentrations of acids.

Intrinsic Causes of Erosion

• The intrinsic causes (acid sources inside the body) for erosion of tooth include the gastroesophageal reflux diseases (GERD) and excessive vomiting related to eating disorders.

1. In these conditions, the gastric acids (having pH as low as below 1 are often regurgitated into the esophagus and mouth; and when these acids come in contact with the teeth extensive erosions occur.
2. In these types of conditions the erosion commonly occurs on the lingual or palatal surfaces of the maxillary teeth.

• Chronic alcoholism can also be a cause of erosion as it is associated with frequent vomiting.

• There are certain other conditions, which are commonly associated with chronic vomiting and thereby cause erosion of teeth.
• These conditions are peptic ulcers, gastritis, pregnancy, drug side effects, diabetics and nervous system disorders, etc.
• Patients with hyperthyroidism can have erosion of teeth, which is about three times higher than normal patients.

ROLE OF SALIVARY FUNCTION IN THE PREVENTION OF DENTAL EROSION

• Salivary function is an important factor in the prevention of erosion since buffering action of saliva can neutralize the intrinsic and extrinsic acids in the oral cavity and this in turn prevents erosion of teeth.

• Moreover, mineral ions in saliva can cause remineralization of the enamel damaged by the acids.

• However, there is a relationship between the salivary flow rate and its buffering capacity (i.e., buffering capacity of saliva increases as the flow rate increases.)

• Therefore, if the salivary flow rate is decreased either due to some medication or disease, there will be more and more chances of erosion of teeth if acids are present in the mouth.

• It has also been found that if there is an increase in the citric acid and mucin content in the saliva, these agents prevent the precipitation of mineral ions from saliva and hampers the remineralization process.

Clinical Features of Erosion

• Acids from extrinsic source cause erosion on the labial or buccal surfaces of teeth and acids from intrinsic source cause erosion on the lingual or palatal surfaces of teeth.

• The commonest site of dental erosion is the gingival third of the labial surfaces of maxillary incisors.

• In chronic severe cases of erosion, the disease can involve even the proximal surfaces of teeth besides involving the labial and lingual surfaces.

• Clinically the condition is manifested by shallow, broad, ‘scooped-out’ concavities on the enamel with highly polished surfaces.

• The shape and size of the lesion may vary considerably and it usually involves multiple teeth.

• There will be cupping of occlusal surfaces o molar teeth or grooving of the incisal edges of anterior teeth with exposure of dentin.

• Increased incisal translucency of teeth also occurs.

• Erosion of the enamel causes raised amalgam restorations wherever they are present.

• Amalgam restorations often have a clean, non-tarnished appearance due to action of acids on the metal surface.

• Preservation of enamel “cuff” on the gingival crevice is common.

• Loss of enamel often causes hypersensitivity in the teeth and it may also trigger secondary dentin formation.

• Severe cases of erosion can cause exposure of pulp in deciduous teeth.

• Micro-radiography shows a gradual demineralization of surface enamel to a depth of about 100 μm.

Treatment of erosion

• Prevention Identification of etiology is important in the management of erosion.

• Proper counseling is needed in case the patient is consuming excessive amount of carbonated beverages.

• Patients with chronic vomiting or GERD are to be referred to concerned specialists for initiation of proper therapy.

• Restorative treatment Depending upon the degree of tooth wear, restorative treatments can be undertaken to maintain the structural integrity of the eroded teeth.