When planning a design, you should consider the possibility of abrasion against standing tooth or the potential for abrasion of the opposing restoration. If the opposing tooth was previously restored, then it is best to select a similar material for the restoration of the opposing tooth. This compromise only improves the tooth contour, protrusion profile and reduces the difficulties associated with plaque retention. This also applies to bulbous molars where a shoulder has to be formed on the root dentin. Typically, porcelain restorations are not strong enough to be used on their own. chewing teeth and as part of bridge prostheses.
Why are wisdom teeth more often removed than treated? Third molars are rudiments that have long lost their functions. If the patient has a narrow jaw, then there is no room left in the row for the eighth tooth. Chewing molars shift towards the central incisors, causing crowding in the smile area. If the tooth has curved roots or impassable channels, requires full treatment of pulpitis, periodontitis and others inflammatory diseases. If the third molar grows normally, without damaging neighboring teeth or disturbing the bite, it is worth saving it. If you remove one “figure eight”, for example, on the lower jaw, then the antagonist on the upper row is deprived of the chewing load. Dental surgeons use potent analgesics - a solution of lidocaine, ultracaine, etc. To extract several “eights” at once they use general anesthesia. Orthodontic correction with braces involves moving teeth to align the entire row. Third molars interfere with this process, so they are eliminated. Do I need to remove or treat wisdom teeth?
What causes improperly growing wisdom teeth?
Eights do not have predecessors in the form of milk teeth, and therefore the process of their appearance is more complex and painful. A focus of infection appears in the oral cavity, which can cause inflammation and even lead to complications.
It is the last, both in terms of eruption time and jaw position, appears mainly or at the end adolescence, or shortly after the 20th birthday. In 25% of people, the “eights” do not appear at all, and no one suffers from this.
Usually wisdom teeth, when they grow, bring a person very painful sensations and discomfort. Patients often turn to their doctors with complaints and questions about how to relieve pain. In this case, the dentist may remove the hood over the molar to facilitate the teething process. When wisdom teeth erupt, you can also use folk remedies.
But if wisdom teeth grew without complications and took their rightful place in the row, then there is no point in removing them: what if they come in handy? Treatment for a wisdom tooth is longer than for “regular” teeth. As a rule, it takes 2-3 months. and requires multiple visits to the dentist. If the carious process has destroyed the crown of the tooth almost to the base, then there is nothing left to save, and all that remains is to get rid of the problematic third molar. It happens that a wisdom tooth turns out to be the most “promising” among its “colleagues”. Then the wisdom tooth is left as a safety net. It is impossible to remove such teeth one by one, because this will lead to gradual curvature of the remaining ones.
In turn, a wisdom tooth growing towards the seven can cause its destruction and the development of pathologies. With the following complaints: upper jaw, With right side, the first incisor is pushed forward relative to the dentition, which disrupts the aesthetic appearance of the patient’s smile and teeth. Left upper tooth wisdom poses a danger to the state of the neighboring seven.
In Russian clinics you can see approximately the following prices: Temporary filling – 420 rubles. Reflective filling (which requires ultraviolet or infrared light before complete hardening) - from 2,750 to 5,000 rubles.
In these cases, preserving the wisdom tooth can sometimes guarantee permanent prosthetics. An exception may be a situation when high-quality dental treatment is impossible (for example, due to impassable root canals).
1. Antagonist teeth are preserved in three points (in the form of a triangle): in the area of the frontal and chewing teeth on the right and left sides. 3then index fingers placed on the occlusal surface of the lower teeth or a roller in the area of the molars so that they simultaneously touch the corners of the mouth, slightly pushing them to the sides. After this, the patient is asked to raise the tip of his tongue and touch the posterior parts of the tongue. hard palate and at the same time make a swallowing movement. This technique almost always ensures that the mandible is placed in a central position.
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Tooth surfaces. For the convenience of describing the features of the relief or localization pathological processes Conventionally, there are 5 surfaces of the tooth crown (Fig. 1).
Rice. 1 . Surfaces (a), edge (b) and axis (c) of the tooth
1. Occlusal surface(fades occlusalis) facing the teeth of the opposite jaw. It is present in molars and premolars. The incisors and canines at the ends facing the antagonists have cutting edge (margo incisalis).
2. Vestibular surface(facies vestibularis) is oriented towards the vestibule of the mouth. In the front teeth that touch the lips, this surface may be called labial (facies labialis), and in the hind ones, adjacent to the cheek, - buccal (facies buccalis).
The continuation of the tooth surface to the root is designated as vestibular surface of the root, and the wall of the dental alveolus, covering the root from the side of the vestibule of the mouth, is like vestibular wall of the alveoli.
3. Lingual surface(facies lingualis) facing the oral cavity towards the tongue. For upper teeth title applies palatal surface(facies palatinalis). The surfaces of the root and walls of the alveoli directed into the oral cavity are also called.
4. Approximal surface(facies approximalis) adjacent to adjacent tooth. There are two such surfaces: mesial surface (facies mesialis), facing the middle of the dental arch, and distal (facies distalis). Similar terms are used to refer to the roots of teeth and the corresponding parts of the alveoli. On these surfaces there is contact zone (area contingens).
Terms denoting directions in relation to the tooth are also common: medial, distal, vestibular, lingual, occlusal and apical.
When examining and describing teeth, the terms “vestibular norm”, “occlusal norm”, “lingual norm”, etc. are used. The norm is the position established during the study. For example, the vestibular norm is the position of the tooth in which its vestibular surface faces the researcher.
Crown and root of the tooth It is customary to divide into thirds. Thus, when dividing a tooth by horizontal planes, the crown is divided into occlusal, middle and cervical (cervical) thirds, and in the root - cervical (cervical), middle and apical (apical) thirds. Using the sagittal planes, the crown of the anterior teeth is divided into medial, middle and distal third, and by the frontal planes - the vestibular, middle and lingual third.
The dental system as a whole. The protruding parts of the teeth (crowns) are located in the jaws, forming dental arches (or rows): upper ( arcus dentalis maxillaris (superior) And lower (arcus dentalis mandibularis (inferior). Both dental arches contain 16 teeth in adults: 4 incisors, 2 canines, 4 small molars, or premolars, and 6 large molars, or molars. When the jaws are closed, the teeth of the upper and lower dental arches are in certain relationships with each other. Thus, the tubercles of the molars and premolars of one jaw correspond to the depressions on the teeth of the same name in the other jaw. In a certain order, opposite incisors and canines come into contact with one another. This ratio of the closed teeth of both dentitions is called occlusion (Fig. 2).
Rice. 2. The relationship between the upper and lower dentition in central occlusion:
a - direction of the teeth axes; b - diagram of the location of antagonist teeth
The touching teeth of the upper and mandible called antagonist teeth. As a rule, each tooth has two antagonists - the main and additional ones. The exceptions are the medial lower incisor and the 3rd upper molar, which usually have one antagonist each. The teeth of the same name on the right and left sides are called antimeres.
Dental formula. The order of the teeth is recorded in the form of a dental formula, in which individual teeth or their groups are written in numbers or letters and numbers. In the complete dental formula, the teeth of each half of the jaws are written down Arabic numerals. This formula for an adult looks as if the recorder is examining the teeth of the person sitting in front of him. This formula is called clinical. When examining patients, clinicians note missing teeth. If all teeth are preserved, the dentition is called complete.
Each tooth is in accordance with the complete clinical formula can be designated separately: upper right - with ; top left ; bottom right; lower left. For example, the left lower second molar is called , and the right upper second premolar.
The World Health Organization (WHO) has adopted a complete clinical dental formula in a different form:
Milk teeth in the full formula are designated by Roman numerals:
Individual baby teeth are pointed in the same way.
According to WHO classification, full clinical dental formula for primary dentition it is written as follows:
In this case, the lower left canine is designated 73, and the upper right first molar is designated 54.
There are group dental formulas that reflect the number of teeth in each group in the halves of the jaw, which can be used in anatomical studies (for example, in comparative anatomical studies). This formula is called anatomical. The group dental formulas of an adult and a child with milk teeth look like this:
This group formula of teeth means that in each half of the upper and lower jaws (or half of the dentition) there are 2 incisors, 1 canine, 2 premolars, 3 molars. Since both halves of the dental arches are symmetrical, you can write one half or a quarter of the formula.
The group dental formula can be written using the initial letters of the Latin names of teeth (I - incisors, C - canines, P - premolars, M - molars). Permanent teeth are designated in capital letters, while baby teeth are designated in lowercase letters. The dental formulas are as follows:
You can write down the complete formula of teeth using letters and numbers:
It is convenient to use such an alphanumeric formula when examining children with baby teeth that have partially erupted. permanent teeth. For example, complete formula The teeth of a 10-year-old child may be as follows:
Individual teeth according to this formula are indicated with an angle sign, an indication of the tooth group and its serial number. For example, the right upper second premolar should be written as follows: , left lower second molar: , primary right upper first molar: t 1 .
Human anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin
In our daily practice, restoration of cavities in the chewing group of teeth occurs quite often. These restorations also occupy an important place in the StyleItalian philosophy: restoration of occlusion, contact surfaces, marginal ridges and indirect restorations of posterior teeth. There are many techniques for recreating the anatomy of the surface of chewing teeth. However, the nuances of occlusion have not yet been resolved.
The same problem always arises: you spend time modeling the chewing surface, checking the occlusion and realizing that the filling is too high. Your previous efforts are in vain. Another problem we often encounter is that after the dental dam is removed, the patient is unable to clench the teeth properly due to the effects of anesthesia and muscle strain. And even after checking with articulation paper, sometimes slight overshoots are still present, which can cause pain in the patient the next day.
When I fabricate restorations, I prefer to have the patient clench the teeth until the composite cures. I realized that having an imprint of the occlusal surface of the opposing teeth is a great way to determine occlusion. This is the method illustrated in this clinical case— technique for making a key for antagonist teeth.
Photo 1: A 22-year-old female patient came to the clinic for an examination. We performed an oral examination and a bitewing x-ray. Caries was detected in teeth 4.6 (MOD cavity) and 4.7.
Photo 2: Antagonist teeth.
Photo 3: Checking occlusion before treatment.
Photo 4: Making a key for antagonist teeth using C-silicone.
Photo 5: Duplicate of antagonist teeth made of plastic.
Photo 6: Checking the manufactured duplicate in occlusion.
Photo 7: Second check.
Photo 8: Removing the etching gel with an air/water gun for 30 seconds.
Photo 9: Adaptation of sectional matrices using plastic wedges and rings for restoration of proximal walls.
Photo 10: Treatment with 2% chlorhexidine for 30 seconds before bonding.
Photo 11: Two layers of a universal adhesive system were applied to the surface of the enamel and dentin.
Photo 12: Polymerization 40 seconds.
Photo 13: The bottom of the cavity was filled with a low-shrinkage flowable composite and cured for 20 seconds.
Photo 14: Proximal walls.
Photo 15: The resulting class I cavities are filled with bulk fill composite (color A2).
Photo 16: The duplicate print is made through Teflon tape for two purposes:
1) to avoid the composite sticking to the acrylic duplicate
2) to compensate for volumetric shrinkage of acrylic plastic.
Photo 17: Fissures and pits appeared on the occlusal surface under the influence of the palatal cusps of the imprint.
Photo 18: Excess filling material was removed, the anatomy of the chewing surfaces was recreated using the fissura instrument. To ensure that the occlusal relationship was not compromised, we again used an acrylic duplicate at this stage.
Photo 19: Curing for 40 seconds, applying brown dye.
Photo 20: Applying glycerin gel and curing for 20 seconds.
Photo 21: Final appearance of the restorations before removal of the rubber dam.
Photo 22: Checking occlusal contacts after rubber dam removal.
Photo 23: Final view of the restorations after polishing.
conclusions
This method has the following advantages:
1) Simplicity: no need for complex material, only C-silicone (impression material) and acrylic plastic are used.
2) Speed of the process: for the production of a silicone key and an acrylic duplicate
it only takes a few minutes.
3) Time-saving technique: if the patient has two or three cavities at once, then sometimes it takes about 15 minutes to correct the occlusion.
4) We can use this method with any modeling technique.
5) We can use it in case of very large cavities.
6) The time spent on modeling the anatomy of the chewing surface of the teeth will now not be wasted: we will not have to adjust the chewing surface at the stage of checking the occlusion.
7) The risk of postoperative sensitivity caused by overestimation of occlusion is reduced.
Special thanks to my teammate Dr. Sarah Dabagh for her contribution to this technique.
The translation was carried out by T. Skovorodko. Please, when copying material, do not forget to provide a link to the current page.
Occlusion Restoration - Technique for Making a Key to Antagonist Teeth updated: June 3, 2018 by: Valeria Zelinskaya
When planning a design, the potential for abrasion of the opposing tooth or the potential for abrasion of the opposing restoration should be considered. If the opposing tooth was previously restored, then it is best to select a similar material for the restoration of the opposing tooth. Metal (especially gold) is the least abrasive material for the antagonist tooth, although in most cases porcelain can be used if there is no potential risk of abrasion, as discussed above. Obviously, if there is no contact with the antagonist tooth, then the restoration will not experience any loads (or they will be minimal) and there will be no concern about abrasion, therefore, you can choose the restoration material as desired. The ability to achieve stable occlusal contacts using available materials should also be assessed. In cases where multiple occlusal surfaces are to be restored, multiple interdental contacts must be restored to create or maintain occlusal stability. Ideally, these conditions should not influence the choice of material. Since multiple contacts are difficult to achieve with porcelain restorations, the restoration must be fabricated by a highly trained dental technician.
Space
(in the intercuspal contact position) is necessary for placing any restoration. Ceramic restorations have a larger volume (hence, require more space) than metal (gold) restorations, which are characterized by strength in thinner sections. The interocclusal space is created after excision of part of the hard tissue. As a rule, the degree of preparation of the occlusal surface of the tooth, which does not affect the retention and stability of the restoration or the health of the tooth, determines the possibility of installing a porcelain restoration on the occlusal surface. Problems arising from limited height clinical crown tooth, will be decided later. There is also a relationship between the height of the clinical crown and the choice of material, especially when working with anterior teeth. Restoration on teeth with a high clinical crown, when the ledge has to continue under the gum, can be performed with a metal crown, otherwise, if you plan to make a porcelain crown, the ledge may extend into the pulp cavity. This compromise only improves the tooth contour, protrusion profile and reduces the difficulties associated with plaque retention. This also applies to bulbous molars where a shoulder has to be formed on the root dentin.Aesthetics and patient wishes
Aesthetic requirements for restorations have increased significantly. The need for an aesthetically satisfying restoration should never be ignored. With any porcelain restoration, you can create ideal aesthetics, this is due to the best optical properties and transparency of the material. Despite the love of some clinicians for metal restorations, it is obvious that they do not meet esthetic requirements, but in some situations (for example, if space for restorative material is limited and a durable material is required) there is no alternative to them. When deciding which material to use, it should be determined whether the patient's wishes are the most important or the only one. important factor when other arguments are questionable. In situations where there is an indication for the use of metal (unaesthetic material) and the main goal of treatment is to provide a functional rather than an aesthetic result, then this should be explained to the patient. All-porcelain restorations are more susceptible to fracture. However, if sufficient space can be provided for an esthetic porcelain restoration without excessive grinding of healthy tissue, and there is no doubt about the durability and fragility of the crown, then there is little argument against making such a restoration.Thus, despite great amount available materials, choose between metal (gold), porcelain or a combination of both (cermets).
Cast metal crown(gold) is considered by many clinicians as the most successful material for extra-coronal restorations, its strength is similar to tooth enamel, it does not deform in the oral cavity under constant load, it can be carefully cast, and preliminary wax modeling allows for good detailing and contouring of the future crown. Such a crown can be thin-walled with a thin edge, so hard fabrics Can be co-sanded slightly. Gold is an unaesthetic material, but despite this, some clinicians prefer it.
All-porcelain crowns are the most aesthetic, although they are fragile and prone to cracks, especially if the crown is thin-walled; the layer thickness should be greater than that of a gold crown. As a rule, the strength of porcelain restoration is not sufficient for it to be used independently on chewing teeth and as part of bridges. Despite this, restorations made from a high-strength crystalline framework can be used as single elements or as continuous bridges when the clinical crown height is sufficient to accommodate the additional pontic mass. Cracks may arise from surface micropores, which may then open under stress and bending, especially if supporting tissue is missing. All this affects how the edge of the crown will be. Dental porcelains are harder than enamel, and if the finished restoration is not glazed, it can wear away the surface of the opposing tooth.
Metal-ceramic restorations (mainly full crowns) have good axial strength and esthetics, but require much more extensive hard tissue preparation than other restorations, due to the need to create sufficient space for the metal frame and more porcelain for an excellent esthetic result. Although porcelain is often used on work surfaces, it is ideal to use metal in these cases to protect the tooth structure (there is no need for extensive hard tissue removal to provide space for a porcelain crown). A metal occlusal surface also does not require the overly contoured, extended occlusal field typically found with porcelain occlusal surfaces, and thus reduces the potential for balancing occlusion (non-working contacts), resulting in a better functional surface that is less likely to cause wear on the opposing teeth.
From this article you will learn:
- whether wisdom teeth are treated or removed,
- indications and contraindications for treatment,
- Is it possible to remove a wisdom tooth - while it has not yet erupted.
But very often the question: is it worth removing wisdom teeth - is asked in relation to already erupted, for example, partially destroyed eighth teeth. Whether such wisdom teeth are treated depends, for example, on the correct position of the tooth in the dentition, or on the presence of an antagonist tooth (with which the closure occurs), etc. Moreover, the opinion of dentists of different specializations may differ radically. For example, when you visit a dental surgeon, the doctor may immediately recommend that you remove it, just so as not to sit idle. The same applies to dental therapists.
It is best for the decision on the need to remove or treat a wisdom tooth to be made by an orthopedic dentist (prosthetist), because the most important thing is to make this decision precisely from the point of view of the need for this tooth for prosthetics in the future. As for the issue of removing figure eights if their eruption is difficult, it is advisable that such a decision be made by an orthodontist. Because, again, when you have an appointment with a dental surgeon, often such doctors do not even look at the length of the jaws, but immediately recommend removing the eights, although they could have erupted quite normally.
Treatment of wisdom teeth –
In this section we will talk about the indications for the treatment of wisdom teeth that have erupted correctly but are partially destroyed. Despite the fact that, due to their nature, these teeth are difficult to treat - in some cases they can be last hope for permanent prosthetics in the future (using bridges), and also serve for good fixation of removable clasp dentures. Therefore, the most competent approach to resolving the issue of removal is an assessment from the point of view of the need and possibility of using it for prosthetics.
Of course, it is worth considering that treatment of wisdom teeth is always more labor-intensive (unless we are talking about banal caries). After all, in in this case treatment and filling of 3-4 sometimes severely curved root canals will require more time and money compared to the treatment of any other teeth..
Therefore, you need to clearly understand whether this tooth is necessary for the dental-jaw system or whether it can be sacrificed. The dentist, of course, will make money from you in any case (both during treatment and during removal), but the main thing is that the intervention brings you benefit. In what cases is it necessary to fight to preserve a wisdom tooth, even if it is seriously damaged by caries?
Indications for preservation of wisdom teeth –
- A wisdom tooth is necessary for prosthetics –
for example, in situations where you are missing the 7th tooth in front, or 6-7 teeth are missing on this side. Or when 6-7 teeth have not yet been removed, but they may soon be removed (for example, due to the presence of inflammatory foci at the apexes of the roots - in the absence of the possibility of re-treatment of these teeth).In all these cases, preserving a wisdom tooth can sometimes guarantee permanent prosthetics with a bridge, or ensure good fixation of a removable one (otherwise, only dental implantation will come to your aid). Therefore, sometimes even if complex and expensive treatment of pulpitis or periodontitis of a wisdom tooth is necessary, this tooth certainly needs and can be saved.
- Other factors –
a wisdom tooth is definitely worth treating if it occupies correct position in the dentition and has an antagonist tooth (participates in chewing). The fact is that tooth extraction always leads to the advancement of the antagonist tooth from the jaw, because in this case, the antagonist will not be exposed to the chewing load when the teeth are closed. Therefore, if a given wisdom tooth occupies right place in the dentition, is involved in the act of chewing and has an antagonist tooth, then it is not advisable to remove it. An exception may be a situation when high-quality dental treatment is impossible (for example, due to the presence of severely curved and impassable root canals).
In what situations is it worth removing a wisdom tooth?
Let's figure it out - why remove wisdom teeth when they have just begun or are about to begin to erupt (after all, sometimes dentists refer for their removal - even in the absence of complaints from the patient). So, in what situations is it necessary to remove a wisdom tooth:
- Wrong position
(Fig. 3-4) –
In dentistry, there is the concept of impacted and dystopic wisdom teeth. A dystopic wisdom tooth is when the tooth has fully erupted, but at the same time it has a violation of its position in the dentition. For example, such a tooth may be located too buccally or tilted towards the cheek, which, therefore, leads to biting when the teeth are closed. If the problem cannot be solved by a little grinding of the hard tissues on the buccal surface of the tooth, then it is preferable to remove it.An impacted wisdom tooth is when a tooth has an eruption pathology, i.e. due to certain reasons, either only part of the tooth crown has erupted, or it cannot erupt at all. For example, a tooth can lie completely horizontally in the jaw or erupt at a strong angle to the 7th tooth in front (in this case, the eighth tooth can only erupt through the distal part of the crown, only partially protruding above the mucous membrane).
- Lack of space for teething
–
if there is not enough space in the dentition for the eruption of eighth teeth, then it is also advisable to remove them. The need to remove wisdom teeth in this case is due to the fact that when they erupt, they contribute to the displacement of the front teeth, which can lead to crowding of the anterior dentition.
- Destruction of the 7th tooth in front
–
Wisdom teeth often erupt in such a way that they are slanted. In this case, with their anterior tubercles they rest against the 7th tooth in front, approximately in the area of its neck (Fig. 6-7). The constant pressure of the wisdom tooth on the enamel of the tooth in front causes destruction of the enamel and the occurrence of caries. Below you can see x-rays, which shows that at the point of contact of the wisdom tooth with the tooth in front, there is a darkening of the crown (the area of destruction of hard tissues).
Sources:
1. Higher prof. author's education in surgical dentistry,
2. Based on personal experience work as a dental surgeon,
3. National Library of Medicine (USA),
4. “Pathology of wisdom teeth eruption” (Rudenko A.),
5. “Qualified removal of third molars” (Asanami S.).
