Abrasion of hard tooth tissues. Treatment of increased tooth wear. Abrasion of baby teeth
CHAPTER 6. ORTHOPEDIC TREATMENT OF PATIENTS WITH INCREASED TEETH WEAR
CHAPTER 6. ORTHOPEDIC TREATMENT OF PATIENTS WITH INCREASED TEETH WEAR
6.1. DEFINITION OF THE CONCEPTS "PHYSIOLOGICAL", "DELAYED" WASH, "INCREASED" WASH. ETIOLOGY AND PATHOGENESIS. CLASSIFICATION OF CLINICAL FORMS OF INCREASED ERASE. PRINCIPLES OF PATHOGENETIC ORTHOPEDIC TREATMENT
The loss of enamel and dentin as a result of their abrasion occurs throughout a person’s life. This is a natural process, and it begins immediately after teething. The rate of abrasion of hard dental tissues depends on many reasons: the hardness of enamel and dentin, the type of closure of teeth, the amount of chewing pressure, dietary habits, a person’s lifestyle, etc.
Natural (physiological) erasure enamel occurs in horizontal and vertical planes. In the horizontal plane, the cutting surfaces of the incisors and canines are erased, and the severity of the tubercles of premolars and molars is reduced. This can be considered as an adaptive reaction of the body: the decrease in the functional capabilities of the periodontium is compensated by a decrease in the height of the clinical crown of the tooth. With the vertical form of abrasion, flattening of the contact surfaces of the teeth occurs and, as a result, their mesial displacement and shortening of the dental arch. it's the same adaptive reaction, which provides a reduction in triangular gaps in the area (atrophy) of gum retraction. Under certain conditions (consumption of soft food, deep incisal occlusion, tooth mobility, etc.), physiological abrasion may be delayed and the anatomical shape of the crowns is preserved.
In addition to natural abrasion, there is increased tooth wear. It is characterized significant loss enamel and dentin in a short time. Depending on the bite, either the cutting surfaces of the incisors and canines, the tubercles of premolars and molars, or the oral and labial surfaces of the crowns are worn away.
Increased tooth abrasion is a polyetiological disease, identified in the International Classification of Diseases as a separate nosological form (according to ICD-10C K03.0).
The reasons for abrasion may be:
Functional deficiency of hard dental tissues due to their morphological inferiority:
Congenital (due to disorders of enamelo- and dentinogenesis in diseases of the mother and child);
Hereditary (Stainton-Capdepont syndrome);
Endogenous in nature (neurodystrophic diseases, disorders of the endocrine apparatus, in particular parathyroid glands, metabolic disorders of various etiologies);
Functional occlusal overload of teeth or dentition caused by:
Defects of the dentition (reduction in the number of antagonizing pairs of teeth);
Parafunction of the masticatory muscles (bruxism, foodless chewing, etc.);
Harmful physical or chemical factors (vibration, physical stress, acid and alkaline necrosis, dustiness);
The combined influence of these factors.
It can be assumed that the term “increased abrasion” combines various conditions of the dental system, often with unclear etiology, but with a pathoanatomical characteristic common to all: rapid loss of hard tissues of all or only part of the teeth.
With increased abrasion, the structure of the hard tissues of the tooth is disrupted: there is a decrease in the clarity of the interprismatic spaces of the enamel, a disruption of the connection between the prisms, and obliteration of the dentinal tubules. Fibrous degeneration and the formation of petrificates are observed in the pulp. If the process of formation of replacement dentin occurs slowly, then hyperesthesia (increased sensitivity) of the teeth appears. The severity of hyperesthesia depends on the rate of hard tissue abrasion, pulp reaction and threshold pain sensitivity human body.
With the first degree of loss of hard tissues, the tubercles and cutting edges of the teeth are erased, with the second, the crowns are erased to the contact areas, with the third, to the level of the gums.
There are three clinical forms increased erasure: vertical, horizontal and mixed (Fig. 6-1).
With a vertical form with normal overlap of the anterior teeth, wear is observed on the palatal surface of the anterior teeth upper jaw and the labial surface of the antagonist teeth on the lower jaw. The situation changes with reverse overlap: the labial surface of the upper front teeth and the lingual surface of the lower ones are erased. The horizontal form is characterized by shortening of the crowns along the horizontal plane: horizontal wear facets appear on the cutting and chewing surfaces. At mixed form increased abrasion develops in both vertical and horizontal planes.
Increased abrasion can be limited and diffuse; accordingly, localized and generalized forms of abrasion are distinguished. The localized form is more common in the area of the anterior teeth, the generalized (diffused) form is noted throughout the entire dental arch.
Depending on the compensatory-adaptive reaction of the masticatory apparatus, two clinical forms of increased abrasion of hard dental tissues should be distinguished: uncompensated and compensated. These forms can be observed in both localized and generalized forms of increased tooth abrasion.
Rice. 6-1. Forms of increased tooth abrasion: a - horizontal; b - vertical; in - mixed
When examining patients for proper planning preparation of the oral cavity and orthopedic treatment must be carried out:
Careful history taking;
X-ray of all teeth;
Electroodontodiagnosis of all teeth;
Study of diagnostic models;
Determination of the height of the lower part of the face, and in case of a decrease of more than 4 mm, X-ray examination of the temporomandibular joints (if possible, an X-ray cephalometric analysis of the facial skeleton should also be performed).
Due to the difference in microhardness of enamel and dentin, worn teeth (II and III degrees of wear) have a typical shape with crater-shaped areas: sharp higher edges of hard enamel and a concave bottom of softer dentin.
With increased abrasion of hard dental tissues, a pathogenetic “vicious circle” arises. Violation anatomical shape teeth (erasure of the cutting edge of the front teeth, chewing tubercles of the lateral teeth) leads to the need for a reflexive compensatory increase in strength muscle contraction, i.e. to increase masticatory pressure to perform the normal function of biting or chewing food. This, in turn, leads to even more tooth wear. The circle is closed (see diagram).
Therefore, orthopedic treatment with restoration of the shape of the occlusal surface of worn teeth is pathogenetic therapy.
In orthopedic treatment of patients with increased abrasion, it is necessary to eliminate the causes and replace the loss of hard dental tissues, breaking the vicious pathogenetic circle. If possible, it is necessary to slow down or stop the abrasion process, and relieve increased tooth sensitivity (a course of complex remineralizing therapy). Methods of orthopedic treatment are determined by the form of increased tooth abrasion, the degree of tooth abrasion, the presence of associated complications: distal displacement of the lower jaw, partial loss of teeth, dysfunction of the temporomandibular joints.
6.2. LOCALIZED FORM OF INCREASED ERASE
Localized formIncreased abrasion affects only individual teeth or groups of teeth, without spreading throughout the entire arch of the dentition. It is most often observed on the front teeth, but sometimes the process can also spread to premolars or molars.
Localized uncompensated formIt is rare and is characterized by a decrease in the height of the crowns of individual teeth with the presence of a gap between them (interocclusal space). Height of the lower part of the face in in this case does not decrease. Orthopedic treatment is carried out with fixed or removable dentures within the interocclusal space.
Localized compensatedthe form is also characterized by a decrease in the height of the crowns of individual teeth, but with the absence of an interocclusal gap due to hypertrophy of the alveolar bone (vacuate hypertrophy) in the abrasion zone. The height of the lower part of the face remains unchanged. In this situation, it is necessary to carry out special preparation (reconstruction of the alveolar part) using bite blocks or orthopedic devices, creating an interocclusal gap to restore worn-out dental tissues. To do this, worn teeth (usually the front ones) are covered with plastic
mass kappa, the lateral ones are disconnected. The functional load in the area of worn teeth causes a restructuring of the antagonist teeth in the alveolar bone, creating space for the prosthesis.
6.3. GENERALIZED COMPENSATED FORM OF INCREASED ABRASION OF HARD TISSUES OF TEETH
The generalized compensated form of increased abrasion of hard dental tissues is manifested by a decrease vertical dimensions crowns of all teeth, but the height of the lower part of the face does not change, as it is compensated by an increase in the alveolar process or alveolar part of the jaws (vacuate hypertrophy).
The facial skeleton in this form is characterized by:
Reducing the vertical dimensions of all teeth;
No changes in the position of the lower jaw and preservation of the vertical dimensions of the face;
Deformation of the occlusal surface and a decrease in the depth of the incisal overlap;
Dental alveolar elongation in the area of all tooth crowns;
Reducing the interalveolar distance;
Shortening the length of the dental arches.
When treating this group of patients, restoration of the anatomical form and function of worn teeth, as well as the appearance of the face, must be carried out without changing the height of the lower part of the face.
When erasing the first degree, you can limit yourself to creating a three-point contact on opposing crowns or inlays. The task becomes more complicated when teeth are worn down to 1/2 the height of the crown or more. Such patients require special preparation, which consists of restructuring the alveolar bone and the myostatic reflex. After creating the optimal interocclusal gap, fixed or removable denture structures are manufactured. In case of abrasion of tooth crowns III degree After special preparation, it is possible to make fixed structures on stump inlays or removable ones. If the above treatment plan is not possible, the roots of the worn teeth are removed, partially with excision of the alveolar bone; treatment is carried out in two stages - immediate and remote.
6.4. GENERALIZED UNCOMPENSIBLE FORM
HIGH ERASE
The generalized uncompensated form of increased abrasion is characterized by a decrease in the height of the crowns of the teeth with a decrease in the height of the lower part of the face. In this case, vacate hypertrophy of the alveolar process is absent or weakly expressed and does not compensate for the loss of crown height. Reducing the height of the lower part of the face, as a rule, leads to shortening upper lip, pronounced nasolabial and chin folds, drooping corners of the mouth, which gives the face an senile expression. Distal displacement of the lower jaw is possible.
Treatment of uncompensated generalized abrasion is as follows:
In restoring the anatomical shape and size of tooth crowns;
Restoration of the occlusal surface of teeth;
Restoring the height of the lower part of the face;
Normalization of the position of the lower jaw.
Among orthopedic structures, preference should be given to inlays, solid artificial crowns and bridges, as well as removable structures with occlusal overlays. According to indications, it is possible to manufacture metal-ceramic and metal-plastic structures. If counter removable and fixed dentures are used in the area of the lateral teeth, then in the area of the front teeth it is permissible to restore the anatomical shape with composite materials. In case of III degree of abrasion, it is necessary to make crowns on an artificial stump. Due to obliteration of the root canals, endodontic treatment is often difficult, so an artificial stump can be fixed using parapulp pins, taking into account safety zones.
It is necessary to take a responsible approach to restoring the occlusal surface. Modeling should be carried out in an individual articulator or according to individual occlusal curves obtained using intraoral recordings of mandibular movements on occlusal ridges made of hard wax. With a two-stage technique, at the first stage, temporary plastic crowns and bridges can be made, and then after 1-3 months they can be replaced with permanent ones, taking into account the abrasion of the occlusal surface.
Restoring the height of the lower part of the face and the position of the lower jaw in the uncompensated generalized form can be carried out simultaneously or gradually. In the absence of diseases of the temporomandibular joint and masticatory muscles, you can immediately increase the height of the lower part of the face in the area of the lateral teeth by 4-6 mm.
When the height of the lower part of the face is reduced by 6 mm or more, its gradual restoration using therapeutic bite dentures is required in order to avoid pathological processes in the masticatory muscles and the temporomandibular joint. Changing the position of the lower jaw (if necessary) can be done using inclined planes(platforms) on the occlusal surface of the therapeutic bite device. IN last years For this purpose, periodontal mouthguards made by vacuum thermoforming are successfully used (Fig. 6-2).
All changes in the position of the lower jaw must be carried out under x-ray control of the temporomandibular joints.
6.5. FEATURES OF WRITING A CASE HISTORY FOR VARIOUS
FORMS OF INCREASED TEETH ABRASION
When writing a medical history, it is necessary to note the patient’s complaints about changes in the anatomical shape of the teeth (horizontal, vertical, mixed forms of abrasion), increased sensitivity, changes in the appearance of the face, functional changes in chewing and in the temporomandibular joint. Then, when collecting an anamnesis, you should find out the most
Rice. 6-2. The relationship of the dentition with increased abrasion: a - before applying a periodontal mouthguard; b - after applying a periodontal mouthguard
probable etiological factors (exogenous and endogenous causes- functional insufficiency or overload of hard dental tissues, occupational hazards). During an external examination, the doctor should pay attention to signs of a decrease in the height of the lower part of the face, when examining the oral cavity - to the shape and degree of abrasion (localized, generalized, compensated, uncompensated), conduct additional studies: x-ray condition of the crowns of teeth and periodontal tissue, condition of the pulp, muscles and temporomandibular joint. Particular attention should be paid to determining the quality of the dentures present in the oral cavity.
Examination of the patient, questioning, objective and additional (special) research methods allow us to formulate a diagnosis and prescribe a treatment plan. In addition to orthopedic measures, the treatment plan may include therapeutic, surgical, orthodontic and preventive measures. A complex approach to treatment contributes to a favorable prognosis for the functioning of the dental system in the future.
TEST TASKS
Indicate the number of the correct answer.
1. Increased (pathological) abrasion of hard dental tissues is called abrasion, which:
1) does not correspond to the type of bite of the patient;
2) does not correspond to the patient’s age;
3) leads to dentin exposure;
4) leads to the appearance of dental hyperesthesia;
5) leads to deformation of the occlusal surfaces of the dentition.
2. The absence of a decrease in the height of the lower part of the face with a compensated form of increased abrasion of hard dental tissues is due to:
1) displacement of the lower jaw;
2) growth of the alveolar part of the jaw;
3) changes in the relationships of the elements of the temporomandibular joint;
4) movement of teeth.
3. For all forms of increased tooth abrasion, it is preferable orthopedic structures:
1) soldered;
2) stamped;
3) removable;
4) non-removable;
5) solid cast.
4. For all forms of increased tooth wear, crowns are contraindicated:
1) stamped;
2) plastic;
3) cast;
4) porcelain;
5) metal-ceramic.
5. The most difficult problem to solve in the orthopedic treatment of increased tooth wear, accompanied by a decrease in the height of the lower part of the face, is:
1) improvement of chewing function;
2) prevention of further tooth wear;
3) normalization of the position of the heads of the lower jaw in the articular fossae;
4) establishing the optimal height of the lower part of the face.
6. The height of the lower part of the face decreases:
1) always with generalized increased tooth wear;
2) if there is generalized increased abrasion of the III degree;
3) if the generalized increased wear of teeth is not compensated by the growth of the alveolar part of the jaw.
Indicate the numbers of all correct answers.
7. For degree I of increased abrasion of hard dental tissues, the following is indicated:
1) tabs;
2) filling;
3) plate prostheses;
4) pin structures;
5) artificial crowns;
6) arc prostheses.
8. For degrees II and III of increased abrasion of hard dental tissues, the following is indicated:
1) filling;
2) tabs;
3) solid crowns;
4) stump crowns;
Abrasion of tooth tissue occurs in every person, which is the result physiological function chewing. Physiological abrasion manifests itself primarily on the mounds of the chewing surface of small and large molars, as well as along the cutting edge and knobs of the fangs. In addition, the physiological surface of the teeth normally leads to the formation of a small area on the convex part of the crown at the point of contact (point contact) with the adjacent tooth.
Physiological tooth abrasion observed in both temporary and permanent dentition. In the temporary dentition, when the incisors erupt, they have 3 teeth on the cutting edges, which are worn away by the age of 2–3 years.
Depending on age, the degree of physiological tooth wear increases. If up to 30 years of age, abrasion is limited to the enamel, then by the age of 40, dentin is also involved in the process, which, due to exposure, becomes pigmented in yellow. By the age of 50, the process of dentin wear intensifies, and its pigmentation takes on a brown color. By the age of 60, significant abrasion of the anterior teeth is observed, and by the age of 70 it often extends to the coronal cavity of the tooth, that is, sometimes even the contours of this cavity filled with newly formed tertiary dentin are visible on the worn surface.
Along with physiological pathological erasure, when there is an intense loss of hard tissue in one, in a group or in all teeth (Fig. 5.11).
Clinical picture. Pathological abrasion (abrasion) of hard dental tissues is quite common and is observed in 11.8% of people. Complete abrasion of the chewing cusps of large and small molars and partial abrasion of the cutting edges of the front teeth are more often observed in men (62.5%). In women, this process occurs much less frequently (22.7%). The reasons for increased abrasion may be the state of the bite, overload due to loss of teeth, improper design of dentures, household and professional harmful effects, as well as the formation of defective tissue structures.
With a straight bite, the chewing surface of the lateral teeth and the cutting edges of the front teeth are subject to wear.
As the cusps of the chewing surface wear away with age, the wear of the incisors progresses intensively. The length of the crowns of the incisors decreases and by the age of 35–40 it decreases by 1/3-1/2. In this case, instead of a cutting edge, significant areas are formed on the incisors, in the center of which dentin is visible. After dentin is exposed, its abrasion occurs more intensely than enamel, resulting in the formation of sharp edges of enamel, which often injure the mucous membrane of the cheek and lips. If treatment is not carried out, tissue abrasion progresses rapidly and the crowns of the teeth become significantly shorter. In such cases, there are signs of a decrease in the lower third of the face, which is manifested in the formation of folds at the corners of the mouth. In persons with a significant decrease in bite, changes in the temporomandibular joint may occur and, as a result, burning or pain in the oral mucosa, hearing loss and other symptoms characteristic of low bite syndrome may occur.
With further progression of the process, the abrasion of the incisors reaches up to the necks. IN in such cases through dentin The tooth cavity is visible, but its opening does not occur due to the deposition of replacement dentin.
With a deep bite, the labial surface of the lower incisors comes into contact with the palatal surface of the upper incisors and these surfaces are significantly erased.
The most pronounced tissue abrasion is observed in the absence of part of the teeth. In particular, in the absence of large molars, which normally determine the relationship of the dentition, intensive wear of the incisors and canines is observed, as they are overloaded. In addition, due to overload, tooth displacement and resorption may occur. bone tissue at the tips of the roots, interdental septa. Often, tooth wear is caused by improper design of removable and fixed dentures. When using a tooth under a clasp without an artificial crown, abrasion of the enamel and dentin at the neck often occurs. As a rule, patients complain of severe pain from mechanical and chemical stimuli.
As is known, the specific conditions of some industries cause the occurrence of occupational diseases. In a number of industries, teeth are damaged and frequently worn out. In workers engaged in the production of organic and especially inorganic acids, examination reveals more or less uniform abrasion of all groups of teeth, and there are no sharp edges. In some places exposed dense smooth dentin is visible. In people with extensive experience working in acid production enterprises, the teeth are worn down to the neck. One of the first signs of abrasion of enamel under the influence of acid is the appearance of a feeling of soreness and roughness of the surface of the teeth. The change from a feeling of soreness to pain indicates the progression of the process. Chewing conditions may change. Upon examination, a loss of the natural color of the tooth enamel is revealed, which is especially visible when dried; a slight waviness of the enamel surface may be observed.
Individuals working in enterprises where there are excess mechanical particles in the air also experience increased tooth wear.
Often, increased tooth abrasion occurs with a number of endocrine disorders- dysfunction of the thyroid, parathyroid glands, pituitary gland, etc. The mechanism of erasure in this case is due to a decrease in the structural resistance of tissues. In particular, increased abrasion is observed in fluorosis, marble disease, Stainton-Candepont syndrome, primary underdevelopment of enamel and dentin.
For therapeutic dentistry, according to M.I. Groshikova, the most convenient clinical-anatomical classification is based on localization and degree of erasure.
Grade I- slight abrasion of the enamel of the cusps and cutting edges of the crowns of the teeth.
Degree II - abrasion of the enamel of the cusps of the canines, small and large molars and cutting edges of the incisors with exposure surface layers dentin.
Grade III- abrasion of enamel and a significant part of dentin to the level of the coronal cavity of the tooth.
Abroad, the Bracco classification is most widespread. He distinguishes 4 degrees of abrasion: the first is characterized by abrasion of the enamel of the cutting edges and tubercles, the second - complete abrasion of the tubercles with exposure of dentin to 1/3 of the height of the crown, the third - a further decrease in the height of the crowns with the disappearance of the entire middle third of the crown, the fourth - the spread of the process to the level of the neck tooth
Beginners clinical manifestation The abrasion of teeth is caused by their increased sensitivity to temperature stimuli. As the process deepens, pain from chemical irritants, and then mechanical ones, may occur.
In most patients, despite pronounced degrees of abrasion, the sensitivity of the pulp remains within normal limits or is slightly reduced. Thus, in 58% of patients with tooth wear, the pulp response to electric current turned out to be normal, in 42% it was reduced to various levels (ranging from 7 to 100 μA or more). Most often, the decrease in electrical excitability of teeth ranged from 6 to 20 μA.
Treatment. The degree of abrasion of hard dental tissues largely determines the treatment. Thus, with degrees I and II of abrasion, the main goal of treatment is to stabilize the process and prevent further progression of abrasion. For this purpose, inlays (preferably from alloys) can be made for antagonist teeth, mainly large molars. long time not susceptible to abrasion. You can also make metal crowns (preferably from alloys). If the abrasion is caused by the removal of a significant number of teeth, then it is necessary to restore the dentition with a prosthesis (removable or fixed according to indications).
Often, the abrasion of tooth tissue is accompanied by hyperesthesia, which requires appropriate treatment (see. Hyperesthesia of hard dental tissues).
Significant treatment difficulties arise with grade III abrasion, accompanied by a pronounced decrease in bite height. In such cases, the previous bite height is restored with fixed or removable dentures. Direct indications for this are complaints of pain in the temporomandibular joints, burning and pain in the tongue, which is a consequence of changes in position articular head in the articular fossa.
Treatment is usually orthopedic, sometimes long-term, with intermediate production of medical devices. The main goal is to create a position of the dentition that would ensure the physiological position of the articular head in the articular fossa. It is important that this jaw position be maintained in the future.
Teeth begin to wear out almost immediately after erupting. This is a natural process that allows all systems and organs to adapt to constant load. Thanks to the physiological abrasion of teeth, the work of the entire dentofacial apparatus occurs evenly, without local overload and with normal periodontal activity. As a result of this natural process, there is a gradual change in contacts from point to plane, the angle of inclination of the teeth changes to make these contacts as physiological as possible. Physiological abrasion affects only the enamel, does not extend to dentin and is localized in the area of the contact planes of the teeth.
Baby teeth are just as susceptible to wear as molars. By the age of three or four years, the teeth of the incisors and cusps of the fangs and molars are worn away, and by the age of six, deep abrasion of the enamel is acceptable, up to partial exposure of the dentin. From the age of six until the complete change of teeth, which on average is completed by the age of thirteen to fourteen years, abrasion of the dentinal layer of milk teeth is permissible. Increased abrasion of primary teeth is diagnosed if the tooth cavity becomes visible or the entire crown is lost, which is indicated by degrees IV and V of abrasion.
Diagnosis of pathological tooth abrasion
If the crowns of your teeth wear down faster than the population average, this may indicate that you have increased, or pathological, tooth wear. During the examination upon consultation, the doctor not only assesses the condition of the enamel, the decrease in the volume of dental tissue and exposure of dentin, but also checks the functioning of the temporomandibular joint (TMJ), skin, the condition of the mucous membranes of the cheeks and tongue, the severity of the nasolabial folds, palpates the masticatory muscles for pain. The doctor checks the symmetry of the opening of the mouth and the position of the jaws in central occlusion. In addition, the lower part of the face is examined and its height is assessed. The sound heard when the teeth are closed is also diagnosed. central position. Normally, this sound should be clear, sonorous and short, but if it is dull and prolonged, then there is a gradual movement of the teeth to a normal position after premature contact, while creaking indicates disturbances in the functioning of the TMJ or problems with the nervous system.
Tooth hypersensitivity is often considered the first sign of increased wear of tooth enamel. The severity of pain depends on the rate of enamel thinning, dentin abrasion, pulp reactivity, the rate of formation of secondary dentin, as well as the number of open dentinal tubules.
Causes of tooth wear
Among the causes of pathological tooth wear, the central place is occupied by the presence of bad habits, such as holding objects in the mouth (needles, paper clips, pipe mouthpieces and musical instruments), love of seeds, consumption of drinks and foods with high acidity (citrus fruits, lemonades, vinegar, etc.), bruxism, expressed in the habit of clenching teeth during the day and grinding teeth at night. Increased abrasion of tooth enamel can be caused by taking certain medications, diseases of the gastrointestinal tract associated with the reverse release of stomach contents, reflux or frequent vomiting, diseases of the cardiovascular, endocrine, and nervous systems. In addition, pathological abrasion of hard dental tissues can be caused by the nature of the work: in metallurgical, granite, cement production, mining, and so on. Poorly manufactured orthopedic structures and malocclusion also cause wear. In this case, the antagonist tooth of the one that was restored with crowns or composite materials suffers.
Classification of tooth abrasion - degrees and forms
The most current classification of pathological tooth abrasion is considered to be that of the authors A.G. Moldovanov and L.M. Demner, who took into account the natural abrasion of dental tissues, which is normally up to 0.042 millimeters per year. As a rule, by the age of fifty it reaches the border of the enamel and more fragile dentin and makes it possible to diagnose the naturalness of the process if ten pairs of teeth interacting during chewing are preserved. In addition, it was highlighted age norm- There are three degrees of tooth wear:
First degree observed by the age of twenty-five to thirty and corresponds to the smoothing of the tubercles, as well as the cutting edges.
Second degree is achieved by the age of forty-five to fifty and reflects the wear of the enamel.
Third degree , as mentioned above, manifests itself by the age of fifty.
In Russian clinical practice, the Bushan classification has gained the greatest popularity. It distinguishes between physiological tooth wear (affects only enamel), transitional (enamel + dentin) and pathological, or increased (dentin), it also considers surfaces that have undergone changes (vertical, horizontal, mixed), the prevalence of the disease (limited or generalized) and emerging increased sensitivity of teeth.
Treatment of tooth wear
If you have been diagnosed with tooth wear, what should you do? Depending on the complexity of the individual case, the doctor may offer one of two options for treating tooth wear: therapeutic or orthopedic. The first is the application of drugs to strengthen enamel and dentin, as well as reduce tooth sensitivity. These are all kinds of pastes, gels, solutions and foams, as well as desensitizers and dentin adhesives. This also includes dental restoration, which involves restoring the dental surface with composite materials.
In orthopedic treatment of pathological tooth wear, the doctor selects prostheses: crowns, bridges, removable and fixed dentures, which will adjust the height of the bite and stop the progression of the disease. It is especially important to choose the right dentures when there is increased abrasion as a result of the absence of molars and premolars in a row. Similar cases lead to the fact that the entire dentition changes position, incisors and fangs are worn out, the temporomandibular joint suffers, and hearing loss is observed. Properly reproduced dentures help preserve the dentition and prevent the development of associated complications.
Mouth guards for tooth wear
If the disease progresses significantly, it is necessary to restore the bite height before installing permanent crowns, otherwise the treatment will not be effective and the dentures will have to be restored after a short period of time. During the adaptation period, which usually lasts three months, all tissues involved in chewing get used to the new bite height: muscles, periodontium, temporomandibular joint. Making a mouth guard against tooth wear during bruxism is a method that significantly slows down the process of destruction.
Tooth wear is a process that affects all people. However, if abrasion becomes excessive, you should definitely consult a doctor, since the consequences of this disease lead not only to aesthetic problems. Incorrect operation muscles leads to dislocation of the temporomandibular joint, which can cause headaches, loss of hearing and vision. And the inability to chew food well is fraught with gastrointestinal diseases. Therefore, do not neglect regular preventive examinations see a dentist, especially if your relatives have experienced increased tooth wear.
DONETSK STATE MEDICAL UNIVERSITY. M. GORKY
DEPARTMENT OF ORTHOPEDIC DENTISTRY
ABSTRACT
Topic: “Excessive abrasion (pathological abrasion) of hard dental tissues. Etiology, pathogenesis. Clinical forms. Diagnostics. Classification. Orthopedic treatment."
The work was completed by a 5th year student
3 groups of the Faculty of Dentistry
DonNMU im. M. Gorky
Lyalka E.V.
DONETSK 2014
Introduction
Pathological abrasion of teeth is a relatively rapidly progressing process, accompanied by a number of morphological, aesthetic and functional disorders. Characterized by excessive loss of enamel or enamel and dentin of all or only individual teeth. The most serious complication of pathological tooth wear is TMJ dysfunction, which, in addition to pain and other dysfunction of the joint, often manifests itself in the form of severe, debilitating pain in the face, head, neck, back of the head, shoulders, tinnitus, hearing loss, and secretory disorders.
Pathological tooth wear occurs in middle-aged people, reaching the highest frequency (35%) in 40-50 year olds, and is more common in men than in women.
In recent years, certain successes have been achieved in the treatment of pathological abrasion of hard dental tissues, however, many issues of etiology, pathogenesis and treatment remain insufficiently studied and controversial.
Classification of pathological abrasion of hard dental tissues
Bracco classification.
The Bracco classification is the most widely used. He distinguishes 4 degrees of erasure:
1. Erasure of the enamel of the cutting edges and tubercles.
2. Complete erasure of the cusps up to 1/3 of the crown height with exposure of dentin.
3. Reducing the crown height to 2/3.
4. The process spreads to the level of the tooth neck.
Classification by A.L. Grozovsky.
A.L. Grozovsky (1946) identifies 3 clinical forms of increased tooth wear:
1. Horizontal
2. Vertical
3. Mixed
Classification by V.Yu. Kurlyandsky.
During the pathological process, V.Yu. Kurlyandsky (1962) distinguishes:
Localized
Generalized
Classification by M.G. Bushana.
One of the most fully reflecting the clinical picture of tooth wear is the classification proposed by M.G. Bhushan (1979). It includes various clinical aspects of a functional and morphological nature: stage of development, depth, extent, plane of the lesion and functional impairment.
Depth of tooth damage:
I degree – complete dentin exposure and shortening that does not reach the equator (within 1/3 of the length of the tooth crown);
II degree – shortening from 1/3 to 2/3 of the crown length;
III degree – shortening of the tooth crown by 2/3 or more
Development stage:
I (physiological) – within the enamel;
II (transitional) – within the enamel and partially dentin;
III (increased) – within dentin
Damage plane:
I – horizontal;
II – vertical;
III – mixed
Length of lesion:
I – limited (localized);
II – generalized
Classification by A.G. Moldovanova, L.M. Demner.
The most modern classification of increased and physiological abrasion of permanent teeth can be considered the classification proposed by A.G. Moldovanov, L.M. Demner (1979). Long-term clinical studies and observations have shown that with an optimal course of physiological abrasion, the natural loss of hard dental tissues per year ranges from 0.034 to 0.042 millimeters. Studies have also shown that abrasion within the enamel-dentin boundary at the age of 50 years and older with a preserved dentition, in which there are at least 10 pairs of antagonist teeth, is a natural process.
1. I form - abrasion of the incisor teeth and smoothing of the cusps of molars and premolars (up to 25-30 years).
2. II form - abrasion within the enamel (up to 45-50 years).
3. III form - abrasion within the enamel-dentin border and partially dentin (50 years and older).
The classification of increased abrasion of hard tissues of teeth includes localized and generalized increased abrasion of hard tissues:
1. I degree - within the enamel, partially dentin.
2. II degree - within the main dentin (without transillumination of the tooth cavity).
3. III degree - within the replacement dentin (with translucency of the tooth cavity).
4. IV degree - abrasion of the entire tooth crown.
Forms of abrasion: horizontal, vertical, faceted, notched, stepped, cellular, mixed.
Classification by A.G. Moldovanova.
As a result of the research, A.G. Moldovanov (1992) proposed a classification of increased and physiological abrasion of primary (temporary) teeth.
Physiological abrasion of hard tissues of temporary (baby) teeth:
1. By the age of 3-4 years of a child’s life, the teeth of the incisors and the cusps of the canines and molars wear out (I form).
2. By 6 years - abrasion within the enamel layer, up to a point opening of the enamel-dentin border (II form).
3. Over 6 years - abrasion within the dentinal layer of teeth before replacement with permanent teeth (III form).
Increased abrasion of hard tissues of temporary (baby) teeth:
1. Transillumination of the tooth cavity (IV form).
2. Abrasion of the entire tooth crown (V shape).
Etiology and pathogenesis
The occurrence of pathological tooth abrasion is associated with the action of various etiological factors, as well as their various combinations. Conventionally, we can distinguish 3 groups of causes of pathological tooth abrasion:
Functional deficiency of hard dental tissues;
Excessive abrasive effect on hard dental tissues;
Functional overload of teeth;
Functional deficiency of hard dental tissues.
This deficiency may be a consequence of endogenous and exogenous factors. Endogenous factors include congenital or acquired pathological processes in the human body that disrupt the process of formation, mineralization and vital activity of dental tissue.
Congenital functional deficiency of hard dental tissues may be a consequence pathological changes ectodermal cell formations (enamel deficiency) or pathological changes in mesodermal cell formations (dentin deficiency) or a combination thereof. At the same time, such a developmental disorder can be observed in some general somatic hereditary diseases: marble disease (congenital diffuse osteosclerosis or osteoporosis of almost the entire skeleton); Porac-Durant syndrome, Frolik syndrome (congenital osteogenesis imperfecta) and Lobstein syndrome (late osteogenesis imperfecta). This group of hereditary lesions includes Capdepont dysplasia.
With marble disease, slow development of teeth, their late eruption and changes in structure with pronounced functional deficiency of hard tissues are noted. The roots of the teeth are underdeveloped, the root canals are usually obliterated. Odontogenic inflammatory processes are characterized by severity and often develop into osteomyelitis.
In Frolik and Lobstein syndromes, the teeth are of normal size and regular shape. The characteristic color of the crowns of the teeth is from gray to brown with a high degree of transparency. The degree of staining of different teeth in the same patient is different. Wear is more pronounced in incisors and first molars. Dentin of teeth in this pathology is not sufficiently mineralized, the enamel-dentin junction looks like a straight line, which indicates its insufficient strength.
The same picture can be observed with Capdepont syndrome. Teeth normal values and shape, but with a changed color, different for different teeth of the same patient. Most often the color is watery-gray, sometimes with a pearlescent sheen. Soon after teeth erupt, the enamel chips off, and the exposed dentin, due to its low hardness, quickly wears out. Impaired mineralization of dentin leads to a decrease in its microhardness by almost 1.5 times compared to the norm. The tooth cavity and root canals are obliterated. The electrical excitability of the pulp of worn teeth is sharply reduced. Affected teeth react poorly to chemical, mechanical and temperature stimuli. Obliteration of the tooth cavity and root canals with this dysplasia begins during the process of tooth formation, and is not a compensatory reaction to pathological abrasion. In the area of the root tips, bone loss is often noted. In contrast to functional dental deficiency in Frolik and Lobstein syndromes, Capdepont dysplasia is inherited as a permanent dominant trait.
Acquired etiological endogenous factors of pathological tooth abrasion include a large group of endocrinopathies in which mineral, mainly phosphorus-calcium, and protein metabolism are disrupted.
Hypofunction of the pituitary gland of the anterior lobe, accompanied by a deficiency of somatotropic hormone, inhibits the formation of the protein matrix in the elements of the mesenchyme (dentin, pulp). A deficiency of pituitary gonadotropic hormone has the same effect. Violation of the secretion of adrenocorticotropic hormone from the pituitary gland leads to activation of protein catabolism and demineralization.
Pathological changes in hard tissues teeth in cases of dysfunction of the thyroid gland are associated mainly with hyposecretion of thyrocalcitonin. In this case, the transition of calcium from the blood to the tooth tissue is disrupted, i.e., the plastic mineralizing function of the dental pulp changes.
The most pronounced disturbances in the hard tissues of teeth are observed when the function of the parathyroid glands changes. Parathyroid hormone stimulates osteoclasts, which contain proteolytic enzymes (acid phosphatase), which contribute to the destruction of the protein matrix of hard dental tissues. At the same time, calcium and phosphorus are excreted in the form of soluble salts - citrate and calcium lactic acid. Due to a deficiency in the activity of the enzymes lactate dehydrogenase and isocitrate dehydrogenase in osteoblasts, carbohydrate metabolism is delayed in the stage of formation of milk and citric acid. As a result, highly soluble calcium salts are formed, the leaching of which leads to a significant decrease in the functional value of hard dental tissues.
Neurodystrophic disorders are of particular importance in the occurrence of functional deficiency of hard dental tissues, leading to pathological wear. Irritation of various parts of the central nervous system (CNS) in the experiment led to increased abrasion of enamel and dentin of teeth in experimental animals.
Exogenous factors of functional deficiency of hard dental tissues include, first of all, nutritional deficiency. Malnutrition (lack of minerals, protein deficiency of foods, unbalanced diet) disrupts metabolic processes in the human body and, in particular, the mineralization of hard dental tissues.
Functional deficiency of hard dental tissues due to insufficient mineralization can result from delayed absorption of calcium in the intestine due to vitamin D deficiency, deficiency or excess of fat in food, colitis, and profuse diarrhea. These factors become most important during the formation and eruption of teeth.
Chemical damage to hard dental tissues occurs in chemical production and is an occupational disease. Acid necrosis of hard dental tissues is also observed in patients with achilic gastritis who take hydrochloric acid orally. Already in the initial stages of acid necrosis, patients develop a feeling of numbness and soreness in their teeth. Pain may occur when exposed to temperature and chemical stimuli, as well as spontaneous pain. Sometimes patients complain of a feeling of teeth sticking when they are closed. As replacement dentin is deposited and dystrophic and necrotic changes occur in the pulp of the affected teeth, these sensations become dull or disappear. Typically, acid necrosis affects the front teeth. The enamel disappears in the area of the cutting edges, and the underlying dentin is involved in the process of destruction. Gradually, the crowns of the affected teeth, being worn and destroyed, shorten and become wedge-shaped.
Among physical factors, radiation necrosis occupies a special place. This is explained by an increase in the number of patients subjected to radiation therapy in the complex treatment of oncological diseases of the head and neck region. In this case, radiation damage to the pulp is considered primary, which manifests itself in microcirculation disturbances with symptoms of pronounced plethora in the precapillaries, capillaries and venules, perivascular hemorrhages in the subodontoblastic layer. In odontoblasts, vacuolar degeneration and necrosis of individual odontoblasts are observed. In addition to diffuse sclerosis and petrification, the formation of denticles of different sizes and locations is observed. In all areas of dentin and cement, demineralization phenomena and areas of destruction are detected. The greatest changes in dental tissues are observed in the period from the 12th to the 24th month after radiation therapy for tumors in the head and neck area. As a result of significant destructive lesions of the pulp, changes in hard tissues are irreversible.
Excessive abrasive effect on hard dental tissues.
S. M. Remizov's long-term observations of the abrasive effect of toothbrushes, tooth powder and toothpastes of various designs convincingly showed that incorrect, irrational use of hygiene and dental care products can turn from a therapeutic and prophylactic agent into a formidable destructive factor leading to pathological abrasion of teeth. Normally, there is a significant difference in the microhardness of enamel (390 kgf/mm2) and dentin (80 kgf/mm2). Therefore, the loss of the enamel layer leads to irreversible wear of the teeth due to the significantly lower hardness of dentin.
Industrial dust in highly dusty enterprises (mining industry, foundry) also has a strong abrasive effect on the hard tissues of teeth. Significant pathological abrasion of teeth occurs among coal mine workers.
Recently, due to the widespread introduction of prostheses made of porcelain and metal-ceramics into orthopedic dental practice, cases of pathological abrasion of teeth have become more frequent, caused by excessive abrasive effects of poorly glazed surfaces of porcelain and ceramics.
Pathological abrasion of teeth may be a consequence of the nature of chewing, in which all teeth or only part of the teeth experience excessive functional load. In such cases, excessive functional load over time can lead to two types of complications: from supporting apparatus teeth - periodontal or from the side of hard tissues of teeth - pathological abrasion of teeth, which more often occurs against the background of functional insufficiency of hard tissues, although it can also be observed in teeth with normal structure and mineralization of enamel and dentin. Overload of teeth can be focal or generalized. One of the reasons for focal functional overload of teeth is occlusion pathology. In the presence of pathology during chewing in various phases of occlusion certain groups teeth experience excessive stress and, as a result, pathological tooth wear occurs. An example is the abrasion of the palatal surface of the anterior teeth of the upper row and the vestibular surface of the lower jaw incisors in patients with a deep blocking bite. Common cause Pathological abrasion of individual teeth is an anomaly in the position or shape of a tooth, leading to the occurrence of supercontact on this tooth during function.
The type of bite may also aggravate the development of pathological tooth wear. Thus, with a straight bite, the processes of erasing hard tissues proceed much faster than with other types of bite.
Partial adentia (primary or secondary), especially in the area of chewing teeth, leads to functional overload of the remaining teeth. With bilateral loss of chewing teeth, the front teeth experience not only excessive, but also unusual functional load. In this case, pathological abrasion of the remaining antagonizing teeth is observed.
Excessive functional load also leads to medical errors when prosthetizing defects in the dentition: the absence of multiple contacts of teeth in all phases of all types of occlusion causes overload of a number of teeth and their abrasion. Often there is abrasion of individual teeth that antagonize teeth that have protruding fillings made of composite materials, due to the inherent strong abrasive effect of composites.
One of the causes of generalized pathological wear of teeth is considered to be bruxomania, or bruxism - unconscious (usually at night) clenching of the jaws or habitual automatic movements of the lower jaw, accompanied by grinding of teeth. Bruxism occurs in both children and adults. The causes of bruxism are not well understood. It is believed that bruxism is a manifestation of a neurotic syndrome and is also observed with excessive nervous tension. Bruxism belongs to parafunctions, i.e. to a group of perverted functions.
Functional overload of teeth.
Typical for pathological abrasion of teeth with functional overload (more than 80%) is a compensatory increase in the thickness of the cement tissue - hypercementosis. In this case, the layering of cement occurs unevenly, the greatest is observed at the root apex.
Changes in the periodontium with pathological abrasion of teeth due to functional overload consist in the unevenness of the width of the periodontal gap from the gingival margin to the root apex. The expansion of the periodontal fissure occurs more in the cervical part and at the apex of the root and directly depends on the degree of functional overload. In the middle third of the root, the periodontal fissure is usually narrowed. Often, in response to excessive functional load, the periodontium of worn teeth develops chronic inflammation with the formation of granulomas and cystogranulomas, which must be taken into account when examining such patients and choosing a treatment plan. Pathological abrasion of teeth leads to a change in the shape of the crown part, which in turn contributes to a change in the direction of action of the functional load on the tooth and periodontium. At the same time, zones of compression and tension appear in the latter, which necessarily leads to characteristic pathological changes in the periodontium.
Thus, with pathological abrasion of teeth resulting from functional overload, a vicious circle is observed: functional overload leads to pathological abrasion of teeth, a change in the shape of the crowns, which in turn changes the functional load necessary for chewing food, increasing it, and this is even more promotes the destruction of hard tissues of teeth and periodontium, exacerbating pathological abrasion. Therefore, orthopedic treatment aimed at restoring the normal shape of worn teeth should be considered not symptomatic, but pathogenetic.
Clinical manifestations
The clinical picture of pathological tooth abrasion depends on the patient’s age, the reactivity of the body, the type of bite, the size and topography of the dentition, the severity of the pathological process and is therefore very diverse. And yet it is possible to identify common signs for this pathology. It is characteristic that the process of increased abrasion of tooth enamel and dentin is not accompanied by their softening.
To the most typical signs Pathological abrasion of teeth includes a violation of their anatomical shape (due to abrasion), dentin hyperesthesia, a decrease in the height of the bite, shortening of the lower third of the face, dysfunction of the masticatory muscles, and in severe cases - painful dysfunction of the temporomandibular joint. However, these signs are not always present simultaneously and clearly expressed - it all depends on the type of tooth wear.
With pathological abrasion of teeth, aesthetic standards are first violated due to changes in the anatomical shape of the teeth. Subsequently, with the progression of the pathological process and significant shortening of the teeth, chewing and phonetic functions change. In addition, some patients, even in the initial stages of pathological tooth wear, experience hyperesthesia of the affected teeth, which interferes with the intake of hot, cold, sweet or sour foods.
The pathological process can affect the teeth of one or both jaws, on one or both sides. In practice there are cases varying degrees damage to the teeth of one or both jaws. The nature and plane of the lesion may be identical, but may also differ. All this determines the diversity of the clinical picture of pathological tooth wear, which becomes significantly more complicated when one or both jaws are partially edentulous.
Dysfunction of the masticatory muscles is manifested by pain when they contract. Raises them bioelectrical activity, and it is also observed in the phase of physiological rest, asynchronous contractions appear, and regional blood circulation in the periodontium is disrupted. These symptoms are observed mainly in cases of pronounced pathological abrasion of the hard tissues of the teeth and only in the decompensated form, when there is shortening of the lower third of the face. Patients with a compensated form of abrasion, accompanied by hypertrophy of the alveolar process of the jaws, do not have such disorders.
Diagnosis of pathological tooth abrasion
To make a correct diagnosis and choose the optimal treatment plan for such a diverse clinical picture of pathological tooth abrasion, it is necessary to carefully examine patients to identify the etiological factors of pathological tooth abrasion and concomitant pathology. The examination must be carried out in full according to the traditional scheme:
interviewing the patient, studying complaints, life history and medical history;
visual inspection;
examination of the oral cavity; palpation of the masticatory muscles, temporomandibular joint, etc.;
auscultation of the temporomandibular joint;
auxiliary methods: study of diagnostic models, targeted radiography of teeth, panoramic radiography of teeth and jaws, EDI, tomography, electromyography and electromyotonometry of masticatory muscles.
During an external examination of the patient’s face, the facial configuration, proportionality and symmetry are noted. The height of the lower part of the face is determined in a state of physiological rest and in central occlusion. The condition of the hard tissues of the teeth is carefully studied, establishing the nature, extent, and degree of wear. Pay due attention to the condition of the oral mucosa and periodontal teeth to identify concomitant pathologies and complications. Palpation of the masticatory muscles reveals pain, asymmetry of sensations, swelling of the muscles, their hypertonicity and suggests the presence of parafunctions in the patient. In the future, to clarify the diagnosis, it is necessary to conduct additional studies: electromyography and electromyotonometry of the masticatory muscles, consult with a neurologist about possible bruxism, carefully question the patient and his relatives about possible grinding of teeth in sleep. This is necessary to prevent complications and select the optimal comprehensive treatment for such a contingent of patients.
Palpation of the temporomandibular joint area, as well as auscultation of this area, allows us to identify pathology, which is often found in pathological abrasion of teeth, especially in a generalized or localized form, complicated by partial edentia. In these cases, careful analysis of diagnostic models and x-ray examination are necessary; frontal and lateral tomograms with closed jaws and physiological rest. Electroodontodiagnostics (EDD) is a mandatory diagnostic test for pathological tooth wear, especially grades II and III, as well as when choosing the design of fixed dentures. Often, pathological abrasion of teeth is accompanied by asymptomatic death of the pulp. As a result of the deposition of replacement dentin, partial or complete obliteration of the pulp chamber, the electrical excitability of the pulp is reduced. In case of pathological abrasion of teeth of the first degree, accompanied by hyperesthesia of hard tissues, EDI usually does not reveal deviations from the norm.
Just like EDI, radiography (sighted and panoramic) is a mandatory diagnostic method that allows us to establish the size and topography of the pulp chamber, topography, direction and degree of obliteration of the root canals, the severity of hypercementosis, the presence of cysts, which are often found with functional overload of teeth, and granulomas in worn teeth. All this is undoubtedly of great importance in choosing the right treatment plan.
Correct diagnosis and treatment planning for patients with pathological tooth wear, as well as monitoring the progress and results of treatment, is facilitated by a thorough study of diagnostic models. Using diagnostic models, the type, shape and degree of pathological abrasion of teeth, the state of the dentition are specified, and when analyzed in an articulator, the nature of the occlusal relationships of teeth and dentition in various phases of all types of occlusion, which is especially important when diagnosing concomitant pathology of the temporomandibular joint and choosing a treatment plan.
Treatment of pathological tooth abrasion
Restoring the anatomical shape of worn teeth depends on the degree, type and shape of the lesion. To restore the anatomical shape of teeth in case of pathological wear of teeth of the first degree, inlays, fillings (mainly on the front teeth), and artificial crowns can be used; II degree - inlays, artificial crowns, clasp dentures with occlusal overlays; III degree - stump crowns, stamped caps with occlusal soldering.
Abrasion is the process of loss of hard dental tissues. Tooth wear occurs both in the temporary and permanent dentition; both occlusal and proximal surfaces; both at reduced speed and at increased speed. Depending on the severity of this process, physiological and pathological abrasion are primarily distinguished.
Physiological abrasion of teeth
Physiological tooth wear is adaptive in nature and occurs as a result of regular contacts of antagonist teeth. The process begins from the moment teeth enter occlusal relationships and, being slow-moving, continues throughout life. The adaptive moment lies in the fact that the teeth adapt to various movements of the lower jaw, causing the smoothness of its movements, reduces the load on the periodontium and helps to increase the integrity of the dentition.
Due to the impact of the contact points of antagonizing teeth on each other, areas are formed in these places that increase the contact (or chewing) surface of the teeth, facilitating the sliding of these teeth, reducing the range of movements of the lower jaw and reducing the load on the temporomandibular joint.
Periodontal functions gradually decline over the course of a person’s life. This is caused by a decrease in the trophic abilities of the neurovascular component of the periodontium, which causes gradual atrophy of the alveolar bone, a decrease in the elasticity of the fibers and a change in the ratio between the intra- and extraosseous parts of the tooth. The tooth in the socket is a lever, and the larger its extraosseous part, the stronger the impact this tooth transmits to the periodontal tissue. Considering that there is a gradual loss of the bone part of the periodontium, the process should worsen over the years, even in people who do not have any pathological changes in the periodontium. But this does not happen normally. But it does not occur due to the fact that physiological abrasion of hard dental tissues reduces the height of the extraosseous part of the tooth. Thanks to this, the ratio of intra- and extraosseous parts of the tooth remains constant, and the load on the periodontium is adequate for age.
In addition to the occlusal surfaces, the proximal surfaces of the teeth are also subject to natural wear. Interdental papillae also undergo atrophy and a decrease in their height over time. But due to the transition of point contact between the teeth into a plane one, the increase in the area of this area and the approach of the lower edge of the area to the gum, no gaps are formed between the teeth and the gum. This allows the body to carry out adequate self-cleansing oral cavity and saves natural look teeth. Also, an increase in the contact surface increases stability in the dentition, and its shortening is compensated by the medial displacement of the teeth.
Thus, we can make a well-founded conclusion that physiological abrasion is interdependent with the state of human health, irreplaceable property of the human masticatory apparatus, contributing to the preservation of its functional and morphological integrity.
Pathological abrasion of teeth
Pathological abrasion of teeth, or, as it is also called, increased abrasion, appears when tooth abrasion occurs according to a scenario different from physiological abrasion. With pathological abrasion, the process ceases to be slow, abrasion of other surfaces of the teeth occurs and, in addition to the enamel, dentin and, accordingly, the pulp of the tooth are involved in abrasion. Very often, pathological abrasion is accompanied by discomfort in the patient and the appearance of corresponding complaints, which almost never happens during a natural process.
At the moment when abrasion becomes a decompensated state, the height of the lower third of the face gradually decreases. This process is accompanied by dystrophic disorders in the temporomandibular joint, the appearance of pain in it and in the masticatory muscles, and decreased chewing function. Outwardly, this is manifested by the severity of nasolabial and chin folds, a decrease in the lower third of the face, protrusion of the chin, and the person acquires a so-called senile facial expression.
Further, due to the displacement of the lower jaw upward, it also shifts posteriorly. In this case, the breathing function also suffers. The volume of the oropharynx decreases due to the distal displacement of the jaw, and, accordingly, the ability to pass required volume air. A person reflexively begins to stoop, dystrophic disorders occur in the spine, and accordingly, primarily in the human musculoskeletal and nervous systems, as well as in the digestive, respiratory, cardiovascular and others.
By different estimates, due to disruption of the functions and condition of the masticatory apparatus and the changes described above, a decrease in human life expectancy can occur by 15 years or more. Against this background, smoking becomes harmless entertainment.
Causes of pathological tooth wear
The causes of pathological tooth wear are very diverse. All of them can be combined into the following groups.
- Functional inferiority of hard dental tissues , caused by a decrease in the qualitative and quantitative characteristics of enamel and dentin. In this case, the process can be:
- Hereditary (eg Capdepont-Stanton syndrome);
- Congenital (disorders of amelo- and dentinogenesis);
- Acquired (metabolic disorders of various etiologies, as well as dysfunctions of the endocrine, vascular, nervous and other systems)
Resistance to abrasion in teeth depends on the processes of calcification of hard dental tissues in the pre- and post-eruptive periods. The leading role in the processes of mineralization is occupied by the neurohumoral regulation of the body. The full function of the parathyroid glands, which are responsible for the balance of calcium and potassium in the body, is especially important.
Capdepont–Stanton syndrome
Disorders of amelo- and dentinogenesis
- Functional overload of teeth , which can occur when:
- Partial loss of teeth;
- Parafunctions (eg bruxism);
- Hypertonicity of the masticatory muscles of various origins;
- Chronic dental trauma;
- Bite disorders;
Pathology can be caused or aggravated in cases where there are defects in the dentition and parafunction of the masticatory muscles. Missing teeth assign their functions to the remaining teeth, and, accordingly, to their periodontium, causing its functional overload. Due to this, the adaptive capabilities of the supporting apparatus of the tooth are reduced, unable to compensate for the decrease in the height of the lower third of the face. With pathological abrasion, secondary cement is deposited on the surface of the tooth root, restructuring in the bone tissue of the alveoli and deformation of the periodontal fissure.
At the same time, a decrease in height may be accompanied by parafunctions of the masticatory muscles, manifested in the form of bruxism, hypertonicity, etc. A decrease in height will certainly lead to dystrophic changes in the temporomandibular joint. Since these processes are interconnected, a so-called “vicious circle” develops, when each of its elements aggravates the other and the entire process as a whole. In this case, establishing cause-and-effect relationships and creating prevention and treatment plans becomes very difficult.
- Occupational hazards may occur at work with the release of acids, alkalis and other substances, taking certain medications, etc. For example, acids reduce the quality characteristics of enamel and dentin, and fine dust is the most common abrasive, which, in combination with adequate dental system becomes aggressive, accelerating the processes of physiological erasure.
Increased abrasion can also be caused by iatrogenic factors, for example, the high hardness of some ceramic materials used in prosthetics and poor-quality polishing of restorations. Even in cases where the hardness of materials does not exceed the hardness of tooth tissue, their aggressive surface turns out to be incomparable with the endurance of enamel, and even more so, tooth dentin.
Classification of pathological tooth abrasion
If we distinguish physiological process From pathological is often not difficult for a doctor, but the manifestations of pathological abrasion are very diverse and need to be classified and specified in each specific case. Therefore, the classification of pathological tooth abrasion is as follows:
- By stage(M.R. Bhushan):
- Physiological – within the enamel;
- Transitional – within the enamel with partial involvement of dentin;
- Pathological – within the dentin.
Physiological abrasion always occurs within dentin, but in at a young age increased abrasion of only enamel along with etiological factor can be diagnosed by a doctor. Dentin wear is characteristic feature pathological abrasion. Dentin involvement may cause hypersensitivity and changes in the pulp, such as deposits of replacement dentin, narrowing of the lumen of root canals up to obstruction of the canals and pulp atrophy and the formation of calcifications (denticles) in the tooth cavity.
- By degree(M.R. Bhushan):
- I – wear down 1/3 of the length of the tooth crown;
- II – wear on 2/3 of the length of the tooth crown;
- III – wear of the tooth crown by more than 2/3.
In the absence of other factors contributing to periodontal disease, pathological abrasion is rarely accompanied by changes in the supporting apparatus of the tooth. This is due to a decrease in the extraosseous part of the tooth and a decrease in the length of the lever, which reduces the load on the periodontium when the teeth are loaded.
- By shape(A.L. Grozovsky):
- Horizontal;
- Vertical;
- Mixed.
With the horizontal form of abrasion, there is a loss of hard dental tissues in the horizontal plane with the formation of horizontal abrasion facets. The process most often occurs on both the lower and upper jaws. The vertical type of abrasion is most characteristic and obvious on frontal group teeth: on the palatal surface of the upper frontal teeth and the labial surface of the antagonists, which is determined by occlusal relationships. However, with, for example, a progenic relationship between the jaws and dentition, wear facets on the upper frontal teeth are observed on the labial side and on the lingual side of the antagonists.
Forms of increased tooth abrasion: a - horizontal; b - vertical; in - mixed
- By degree of compensation(E.I. Gavrilov):
- Compensated – without reducing the height of the lower third of the face;
- Decompensated – with a decrease in the height of the lower third of the face;
The dentofacial system has relatively high compensatory capabilities. Following the loss of hard dental tissues, a restructuring of the alveolar process of the jaws occurs and the teeth are displaced into the area of the defect or the area of absence of occlusal relationships. The so-called dento-alvelar lengthening, or the Popov-Godon phenomenon. Depending on the degree of such restructuring, pathological abrasion of teeth is differentiated into compensated, when tooth displacement prevents a decrease in the height of the lower third of the face, and decompensated, when compensatory restructuring is not able to fully eliminate the defect or is completely absent.
- By length(V.Yu. Kurlyandsky):
- Localized – increased wear of individual teeth or a group of teeth;
- Generalized.
Localized abrasion is more often observed in the frontal part of the dentition, for example, with a deep bite. This type of abrasion is also locally compensated by the body due to local hypertrophy of the alveolar process. In this case, the support points of the height of the lower third of the face, which fall on the chewing teeth, remain intact, without disturbing the occlusal relationships and the position of the elements of the temporomandibular joint.
In the generalized form of the process, the crowns of all teeth are captured, with a violation of the bite height. In this case, the degree of compensation depends on the individual characteristics of the organism.
The article was written by N.A. Sokolov. Please, when copying material, do not forget to provide a link to the current page.
Teeth wear updated: February 25, 2018 by: Valeria Zelinskaya
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