Crowns for teeth: types, indications and contraindications, prices. Indications and contraindications for the manufacture of combined crowns Indications and contraindications for the manufacture of combined crowns

Family and relationships 05.10.2021

Destruction or traumatic breakage of a significant part of the crowns of the anterior teeth and premolars, when it is impossible to restore them with fillings or inlays;

Anomalies in the development and position of the anterior teeth in adults, which for any reason cannot be eliminated by orthodontic methods; - pathological abrasion of hard tissues of teeth;

Fluorosis, wedge-shaped defects;

Anomalies in the development of hard dental tissues (impaired amelogenesis);

Aesthetic defect of the crowns of natural teeth (discoloration, distortion of shape, loss of gloss, etc.);

Non-compliance of existing artificial crowns (metal, plastic, combined) and bridges with aesthetic and other requirements;

Included dentition defects.

Metal-ceramic crowns and bridges can also be used as a splinting structure for mild to moderate periodontitis. Each of these indications should be linked to a specific situation.

For example, with significant carious destruction or traumatic fracture of most of the crowns of natural teeth, it is necessary to make cast stump pin tabs before using metal-ceramic prostheses.

This is due to the fact that with a significant carious destruction of the anterior teeth and premolars, the hard tissues of their crowns are very weakened and, under the influence of an occlusal load, can break off along with the metal-ceramic structure reinforced on them.

The risk of such a complication increases dramatically in patients with anomalies of teeth and bite, parafunctions of masticatory muscles (bruxism). In case of traumatic breakage of a significant part of the tooth crown, a cast stump pin insert is necessary to improve the fixation of metal-ceramic crowns and bridges.

Anomalies in the development of the anterior teeth (size and shape) in adults are undoubtedly an indication for the use of metal-ceramic crowns, since plastic crowns do not meet the increased functional, preventive and aesthetic requirements.

Porcelain crowns meet aesthetic standards to the greatest extent, surpassing even metal-ceramic structures in this respect. However, porcelain is brittle, and they break under bending forces under the influence of occlusal loading.

This is especially true for patients with deep bite, prognathic and progenic ratio of dentition with deep incisal overlap, masticatory muscle parafunctions (bruxism) and pathological abrasion of hard dental tissues.

In these cases, preference should be given to metal-ceramic crowns, which have not only the high aesthetic qualities of porcelain crowns, but also the advantages of solid cast prostheses. With regard to anomalies in the position of the anterior teeth in adults, orthodontic treatment is indicated here.

However, due to age-related changes in the bone tissue of the jaws, hardware correction of the position of the teeth is longer than in children, does not always give positive results, more often than in childhood, relapses and other complications are observed.

All this makes many adult patients refuse such treatment. In these cases, after depulpation of the teeth, metal-ceramic crowns and bridges and cast stump pin tabs with a changed axis of inclination of these teeth are used.

With pathological abrasion of hard tissues of teeth, porcelain is not the only material for facing cast prostheses. Along with ceramics, high-strength plastics (isosite, etc.) are used in such cases.

Due to the fact that in this pathology there is a danger of ceramic chipping, in order to achieve a high aesthetic effect, it is sufficient to veneer only those crowns and facets that are visible in a given patient when talking and smiling. Most often, these are prostheses in the area of incisors, canines and first premolars, less often second premolars, even less often - first molars.

Therefore, when deciding which crowns and facets of a solid-cast metal-ceramic prosthesis in this patient should be veneered with ceramics, you need to talk with him and determine the teeth that will be visible. It is these crowns and facets that it is advisable to veneer with porcelain, and it is better to leave the remaining parts of the prosthesis in the area of the molars of the upper and lower jaws completely metal.

Occlusal contact on metal crowns and facets in the area of the indicated teeth of the upper and lower jaws ensures the stability of the interalveolar distance (bite height) and favorable conditions for the construction of metal-ceramic prostheses in the area of the anterior teeth and premolars. In addition, to prevent porcelain chipping, we recommend that the surfaces of the closure of crowns and facets in the area of molars and second premolars be left metal.

Vestibular and chewing surfaces of the first, and sometimes the second premolars and all anterior teeth, it is advisable to veneer with ceramics. Such prostheses, fully satisfying aesthetic requirements, can withstand increased occlusal load and abrasion for a long time.

For the same purpose, it is better to first make removable, non-removable or a combination of them (according to indications) in the area of the posterior teeth, restore the height of the bite, and then make and strengthen metal-ceramic crowns or bridges in the area of the anterior teeth.

As for fluorosis, wedge-shaped defects and impaired amelogenesis, in these types of pathology, the indications for the use of metal-ceramic crowns and bridges are quite wide.

If with wedge-shaped defects it is still possible to restore the integrity of the crowns of natural teeth with various filling and composite materials, then with fluorosis and impaired amelogenesis, this is not possible. With these types of pathology, metal-ceramic crowns are indicated.

Porcelain crowns are less durable and break more often. The aesthetic defect of the crowns of natural teeth, especially the anterior ones (discoloration, shape disturbance, loss of gloss, etc.), is currently one of the most common indications for the use of metal-ceramic crowns and bridges.

Old designs of artificial crowns (metal, plastic, combined) and soldered bridges must be replaced not only for aesthetic reasons, but also because they also do not meet functional and preventive requirements.

Concerning the indications for the use of metal-ceramic prostheses for defects in the dentition, it must be remembered that it is advisable to use them only with the included defects in the dentition (Class III and IV according to Kennedy) and the absence of 1-2 teeth.

With large defects in the dentition, the use of metal-ceramic prostheses is associated with the risk of chipping of the ceramic veneer. In patients with intact periodontium in the area of the anterior teeth, such prostheses can also be used in the absence of three teeth, since the occlusal load in this section of the dental arch is less than in the area of premolars and molars.

It is not advisable to use cantilever metal-ceramic prostheses, especially with end defects in the lateral parts of the dental arches. The risk of using such prostheses is less when the antagonists are artificial teeth of removable dentures.

We cannot agree with the authors who consider periodontitis a contraindication to the use of metal-ceramic prostheses and are convinced that metal-ceramic crowns and bridges can be used for mild and moderate periodontitis.

Clinical, radiological and functional studies conducted at our department have shown that ceramic-metal prostheses provide reliable immobilization of mobile teeth, do not adversely affect marginal periodontal tissues and meet aesthetic requirements.

In 96.8% of patients with mild to moderate periodontitis, the use of ceramic-metal constructions leads to stabilization of the pathological process, as evidenced by the results of X-ray and functional studies.

The resorption of the bone tissue of the alveolar process at the same time slows down or stops. The results of reoparodontography indicate an improvement in regional blood circulation in the tissues of the marginal periodontium.

Oral hygiene is also significantly improved, since there is practically no plaque (plaque) on the glazed surface of metal-ceramic prostheses.

This is evidenced by the change after orthopedic treatment of the average values of the plaque index PI, which characterizes the hygienic state of the oral cavity.

However, it should be remembered that, firstly, the indication for the use of such prostheses is mild to moderate periodontitis in remission, after anti-inflammatory therapy and appropriate orthopedic preparation of the dentition.

Secondly, metal-ceramic prostheses must meet certain design requirements.

The edges of metal-ceramic crowns should be located on a circular ledge of 135°, formed at the level of the gums. The body of the bridge should not be adjacent to the cervical part of the abutment teeth in order to avoid injury to the marginal periodontal tissues.

Before glazing, it is necessary to carefully align the closure of crowns and facets with antagonists in the central, anterior and transverse occlusions and in different phases of articulation.

Finished metal-ceramic prostheses should first be strengthened temporarily for 2-3 months. to identify and eliminate their shortcomings and possible complications. Patients with periodontitis with metal-ceramic prostheses should be under dispensary observation, if necessary, anti-inflammatory periodontal treatment and occlusion correction should be carried out.

The use of metal-ceramic crowns and bridges in accordance with the listed indications is possible only in cases where an interocclusal space of 1.8 mm can be created in the process of preparing teeth or restoring the bite height.

The use of metal-ceramic prostheses is contraindicated: in the presence of teeth with live pulp in patients younger than 18-20 years; with severe periodontitis.

The first contraindication is associated with the need for deep preparation (up to 1.8 mm) of hard tissues of the teeth and the risk of damage and death of the pulp due to the large size of the tooth cavity with thin walls, its proximity to the tooth surface and wide dentinal tubules in children, adolescents and young people.

The second contraindication is explained by the high hardness of ceramics, its indelibility, as well as the rigidity of the ceramic-metal structure, which can cause functional traumatic overload of the periodontium of supporting teeth or their antagonists and aggravate its condition.

Relative contraindications to the use of ceramic-metal fixed prostheses are: bite anomalies with deep incisal overlap; small size of the incisors of the lower jaw; pathological abrasion of teeth; parafunction of masticatory muscles (bruxism); insufficient height of the crowns of natural teeth, especially in the presence of defects in the dentition.

In the presence of these factors, the manufacture and use of metal-ceramic prostheses is difficult or even impossible due to the risk of damage to the tooth pulp and the development of all kinds of complications at different times after strengthening the structure.

In patients with a deep blocking bite, the mandibular incisors completely overlap with the maxillary incisors.

The latter have an oral inclination and fit snugly to the antagonists, embracing them from the vestibular side. The crowns of the incisors of the upper jaw are often worn and thinned from the oral surface, so it is impossible to grind them to the desired depth without damaging the pulp and create a gap between the upper and lower front teeth for constructing a metal-ceramic crown.

Certain difficulties also arise with prognathic and progenic occlusion with deep incisal overlap.

With these types of bite, there is also a risk of functional traumatic overload of the abutment teeth and their antagonists, which can lead to pathological changes in periodontal tissues, loosening of the teeth and chipping of the ceramic veneer.

The incisors of the lower jaw have thin, fragile crowns, as a result of which during their preparation, especially when creating a ledge in the cervical region, there is a real danger of pulp damage.

With pathological tooth wear, bruxism and other parafunctions of the masticatory muscles, accompanied by a displacement of the lower jaw, there is a high excitability and increased muscle tone and, as a result, a strong compression of the dentition.

The use of metal-ceramic crowns and bridges in these conditions can lead to overloading of the abutment teeth and spalling of the ceramic veneer. In addition, with pathological abrasion of teeth, a decrease in the interalveolar distance (bite height) and crowns is observed.

Without preliminary orthopedic treatment and the creation of an interocclusal gap, the design of metal-ceramic prostheses is impossible.

We attribute these contraindications to relative ones, since with appropriate orthopedic (orthodontic) preparation of the dentition and restoration of the interalveolar distance, it is possible to create more favorable conditions for prosthetics and use metal-ceramic crowns or bridges.

At the same time, it is necessary to strictly monitor the correct implementation of all clinical stages and the technology for manufacturing prostheses.

Special care must be taken when preparing mandibular incisors with live pulp: a deep ledge should not be created - you can limit yourself to the ledge symbol or prepare without a ledge.

It is not uncommon to attempt to create a circular ledge on these teeth resulting in pulpal injury.

It must be remembered that ceramic-metal bridges are used mainly for small defects in the dentition (1-2 teeth). With large defects (3-4 teeth), the slightest deformation of the intermediate part of the bridge can lead to cracking and spalling of the ceramic veneer. At the same time, the use of cantilever metal-ceramic prostheses should also be sharply limited or completely excluded.

Teeth are normal Dental prosthetics What are the advantages of cast crowns over stamped crowns?

Modern dental technologies make it possible to produce two types of metal crowns: cast and stamped. Advantages and features of cast crowns, as well as their estimated cost in Moscow dental clinics: here is a list of questions, the answers to which you will find after reading this publication to the end.

Cast crowns: indications and contraindications

Metal is an ancient and popular material used in the manufacture of dentures, because medical alloys are durable and resistant to destruction in an acid-base environment.

A cast crown is an excellent option for prosthetics of chewing teeth.

It may seem incomprehensible to some that, given the rapid development of medicine, offering patients in dental clinics more advanced methods of restoring teeth, some people still turn to morally and technologically obsolete metal dental structures. In fact, a simple metal in dentistry has its own indications for use:

The need for prosthetics of molars, which are practically invisible from the side. If a patient needs to get a large number of dentures, then this saves an impressive amount of money, while at the same time he receives functionally restored teeth.
for the installation of the bridge.
Restoration of teeth (including incisors) with a very short crown part. Such a pathology is not only an aesthetic disadvantage, but also makes prosthetics impossible with the help, since it has thicker walls and requires significant preparation.
Limited financial resources of the patient. Unfortunately, every year the cost of dental services increases, which does not completely eliminate the need for timely professional care for the oral cavity.

There are also contraindications, which in almost all respects coincide with the general contraindications for prosthetics:

poor condition of the roots;
periodontal disease;
untreated carious lesions;
mental and neurological abnormalities;
diseases of the heart and blood vessels;
viral infections;
individual allergic reactions to alloy components.

Any type of prosthetics, except for the most urgent cases that cannot be postponed, is contraindicated during gestation and during breastfeeding.

5 main advantages of cast crowns over stamped crowns

The two types of metal crowns that exist today - both cast and stamped - for all their visual similarity, have many differences, and the first type wins both in terms of quality and aesthetic characteristics:

More advanced manufacturing method, allowing to achieve maximum fit to the tooth, at the same time without squeezing the gum mucosa. This became possible due to the fact that the cast structure is cast according to a previously made mold, while the stamped one acquires the desired shape by extrusion. The second way is much more difficult to restore the tooth in its original form, and this has a positive effect, including on the quality of chewing food, and on the absence of periodontal inflammation.
Durability: the service life of the product is about 10 years, which significantly exceeds the service life of stamped structures. The reason lies in the source material - the blank for the stamp is thinner and softer, therefore it is erased and deformed faster.
Manufactured from more advanced alloys- chrome cable (KHS), nickel-chromium (NHS), titanium, with the use of precious metals and stainless steel, but the first is most often used. The cast KHS crown contains special additives, due to which its surface is particularly smooth and does not accumulate bacteria.
Allows maximum preservation of dental tissue- due to increased strength, orthopedic treatment with cast all-metal crowns is carried out with minimal tooth preparation, which is especially important in cases where a healthy tooth has to be taken under the crown for the installation of a bridge.
Affordable price: unlike many more modern methods of prosthetics (metal ceramics, implantation), the cost of a cast crown makes it a truly budget option, available even to pensioners. And given the fact that the main visitors of orthopedic dentists are precisely this segment of the population, the price factor cannot be discarded when listing the advantages of products.

If the treatment requires the installation of a bridge of cast crowns, then it is possible to use various combinations - in this case, cast crowns with ceramic lining are placed in the smile zone, and ordinary metal prostheses are placed on the chewing teeth.

Cost in Moscow clinics

Clinic	Address	Price
Dr. DostaLet	st. Nametkina, 3	From 86USD
Denta Bravo	st. Nelidovskaya, 16	84-127 USD
Ilatan	Marksistskiy pereulok, 3	From 79USD
Denta Prestige	Leningradsky prospekt, 77, bldg. four	From 82USD
Apollonia	Simferopol Boulevard, 24, bldg. 2	From 84USD
CJSC "Medical Services"	st. Builders, d.6, bldg. one	43-93 USD

Step by step installation technology

Expert opinion. Dentist Avdeev P.N.: “The process of prosthetics itself takes place in several stages. Very often, the patient's teeth are in a deplorable state, therefore, first of all, the dentist treats all carious cavities. In aged patients, cases of periodontal disease are also not uncommon, which, as already mentioned above, are a direct contraindication to any orthopedic manipulations in the oral cavity. Therefore, the first step is the treatment of mucous and diseased teeth and the removal of those that can no longer be restored.

Further actions practically do not differ from the general protocol of dental prosthetics:

As a rule, dental prosthetics with cast structures are not difficult, but still, when choosing a doctor, take an interest in his experience - it should be at least 5-6 years.

Dental crowns are fixed prostheses that restore damaged teeth or replace lost ones. Experts recommend using crowns for prosthetics if the tooth is significantly destroyed - at least 70%. If it is necessary to correct damage that is smaller in volume, fillings or dental inlays are used.

The crown restores the anatomical shape of the tooth and its functionality.

The crown resembles a cap in appearance; the design is made in a dental laboratory according to individual casts. The product can be used as an independent prosthesis, and can be used as a support for fixing clasp and bridge prostheses. Designs are widely used in the process of implantation.

For prosthetics of damaged and lost teeth, crowns are used according to the following testimony:

restoration of a tooth with a significant destruction of its crown part by more than half,
pathological abrasion of enamel,
implantation,
restoration of the anatomical shape of the tooth,
fluorosis,
restoration of a tooth that has suffered from chips and cracks,
anomalies in the shape and arrangement of teeth in a row,
for support and protection against tooth decay with bulk filling.

Crowns are also used in pediatric dentistry to protect teeth that have been severely damaged by a carious process, when it is impossible to install a filling.

Contraindications to the installation of dental crowns:

tooth mobility in advanced stages of periodontal disease,
allergy to construction materials,
thin tooth walls
periodontal disease,
low crown part of the tooth,
abnormal bite.

Types of prostheses

There are several types of crowns depending on the materials and manufacturing technology:

Metal-ceramic is still the most popular type of dentures due to the optimal price-quality ratio. High strength indicators make metal ceramics an ideal option for restoring chewing teeth.

Here you can see metal ceramics on the front teeth.

A ceramic-metal product consists of a metal frame, on top of which a ceramic cladding is applied. The design is bulky and heavy. Before installing the prosthesis, the tooth is depulpated and grinded from all sides, this is necessary for a tight fit of the crown.

Metal ceramics can be used for the restoration of anterior teeth, but some nuances should be taken into account:

the metal base is enlightened,
a dark rim may appear at the junction with the gum,
a single crown will stand out noticeably against the background of the patient's native teeth.

Ceramics

This is a modern type of crowns that does not have metal elements. made according to individual impressions. The product has high aesthetic qualities and is excellent for prosthetics of the smile line.

Metal-free ceramics

This is the most durable and expensive type of dental crowns. For their manufacture, zirconium dioxide is used - a material unique in its properties, which is identical in appearance and structure to natural enamel. They refract light in the same way as natural tooth enamel, so often even dentists cannot distinguish a crown from a tooth. Metal-free crowns are produced using innovative technologies and modern equipment.

Metal-plastic

The frame of the structure is made of metal, the cladding is made of composite plastic. This is not the best option for prosthetics, as the plastic absorbs odors, quickly darkens and cracks.

Plastic crowns (temporary)

Such crowns have their purpose - they close and protect the turned tooth for a period while a permanent crown or other prosthesis is being made. Temporary crowns are light, aesthetic, help the patient avoid discomfort and get used to the prosthesis in the oral cavity.

Hardware

Metal crowns are now rarely used, but gold products remain popular despite the development of technology and the introduction of new high-quality materials. Gold crowns are durable, they do not cause allergies and withstand high chewing loads.

What are the advantages and disadvantages of crowns?

We offer you a comparative table that shows the advantages and disadvantages of different types of crowns:

Product type	Advantages	Flaws
cermet	· Affordable price. · Durability, durability. Good aesthetic performance.	Before installation, a significant layer of hard tooth tissues is ground. The product is heavy. The metal frame is translucent, so it is undesirable to put metal ceramics on the front teeth.
Ceramics	High aesthetic performance. The material transmits light, very similar in structure to enamel. Can be installed without removing the nerve.	Not recommended for use with bridges. · High price.
Metal-free ceramics (oxide, zirconium dioxide)	The product is durable and lightweight. Perfect appearance, indistinguishable from a real tooth. Maximum tight fit to the tooth and gum line. · Long service life. Can be used on both anterior and posterior teeth.	The most expensive type of crowns.
Metal-plastic	· Affordable cost. · Fast production.	· Outdated technology. · Service life about 2 years. · Plastic changes color, cracks.
Metal crowns	· Durability, reliability. · Service life — up to 5 years. · Affordable price.	Due to its unaesthetic appearance, it is rarely used for anterior teeth. Not suitable for patients with metal allergies.

What crowns are better to put on chewing teeth?

Metal crowns can be placed on chewing teeth - they are reliable and durable.

What type of crown is best for prosthetics of chewing teeth? Before making a choice, the dentist will take into account a number of factors:

a damaged tooth can be restored and protected by metal-free ceramics,
if the walls of the tooth are thin, in this case it is advisable to use cermet,
if the patient is limited in finances, the doctor may offer him a metal structure.

The main purpose of chewing teeth is to grind food, therefore, during prosthetics, the main task of the dentist is to restore this function. The ideal option in this case is cermet, since the ratio of aesthetics and functionality is optimal here.
Of course, if the patient has the money, he can supply metal-free ceramics. In any case, the final decision is made by your doctor.

Restoration of anterior teeth

You can fix the crown on the frontal tooth, provided that its root remains intact. If the tooth is missing, the product is fixed on the implant. You can still save money on the restoration of chewing teeth, but this option will not work with the front teeth, since they are visible when smiling and talking.

Of course, ceramics would be ideal in this case, and metal-free ceramics would be better. It is durable and aesthetic. If the patient cannot afford a ceramic crown, the dentist will offer a classic - ceramic-metal. This is also a good option, since well-made and well-installed metal-ceramic crowns on the front teeth look very good.

No, it is not painful, since all manipulations are carried out under the influence of a local anesthetic, the type and amount of which is selected individually. In order for you to understand what the doctor will do at each stage of prosthetics, we will acquaint you with the procedure for installing crowns in more detail:

Training

This is the first and very important stage on which the quality of prosthetics depends. At the first visit, the specialist will examine the oral cavity and also direct you to an x-ray. According to the results of the examination and the picture, the doctor will determine the condition of the mucosa, teeth, and, if necessary, prescribe treatment. Plaque and stone are removed without fail.

Preparing a tooth for a crown is as follows:

Turning is a prerequisite for prosthetics with crowns, and more hard tissues are removed for metal ceramics than for ceramics.

Laboratory stage

An impression is taken from the turned tooth, it is needed by a dental technician, who, on its basis, makes a crown. During the production of the prosthesis on the turned stump, the patient is fixed with a temporary plastic crown, which protects the turned tooth and hides the defect.

Direct crown placement

First, the crown is tried on and fixed with temporary cement. If the patient feels comfortable, the product does not interfere with him and does not disturb the general bite, he is fixed with permanent cement.

Why a tooth can hurt under a crown: possible complications

Pain under the crown is a common complaint of patients. But one thing is the discomfort immediately after installation and a few days after it, when anesthesia comes out and getting used to the crown. But if the patient begins to have a toothache after a few months, and sometimes even years after the installation of the crown, this indicates the development complications:

Poor preparation for prosthetics (poorly disinfected instruments, poorly sealed root canals). As a result, an infection begins to multiply in the channels, which causes the development of the inflammatory process.
The dentist perforated the walls of the canals during their processing. This can happen both due to the fault of the doctor, and due to the pathological curvature of the root canals. Perforation can also occur during insertion in the pin channels.
Tool break. Yes, and such troubles sometimes happen in dental practice. Most often, the reason is the same curvature of the root canals. A piece of the instrument remains in the canal, and if the dentist does not notice this immediately and leaves it there, inflammation will occur over time. The tooth will have to be re-treated.

Not all patients know that you can play it safe from such troubles if you take an x-ray after installing the crown. In case of poor-quality treatment, everything will be visible on the picture: not completely filled root canals and the same broken piece of the instrument. In this case, the clinic must pay for your re-treatment of the tooth. If the complication appears after a while, you will have to treat the tooth at your own expense.

Price and service life

We offer you to get acquainted with the average cost of different types of crowns and their service life:

What determines the cost of the crown, what does the price consist of? Factors that affect pricing:

pricing policy of the clinic: each dental clinic focuses on a specific segment of consumers,
staff qualifications: an orthopedist (paying him 20% of the cost of the prosthesis), a dental technician (paying him about 25% of the cost of the prosthesis),
type of materials (the most expensive is zirconium dioxide),
the presence of a dental laboratory in the clinic (if not, the clinic will have to conclude an agreement and cooperate with a third-party laboratory, which will affect the price formation).

Send your good work in the knowledge base is simple. Use the form below

Students, graduate students, young scientists who use the knowledge base in their studies and work will be very grateful to you.

Hosted at http://www.allbest.ru/

St. Petersburg State University Academician I.P. Pavlova

Department of Orthopedic Dentistry

on the topic "Artificial crowns"

Performed

Ponomarenko A.A.

377 group

Checked by: Bystrova Yu.A.

St. Petersburg

1. Types of artificial crowns

3. Contraindications

Bibliography

1. Types of artificial crowns

The most common prostheses used to restore a destroyed tooth crown are full artificial crowns. Due to the fact that they have a different design and are designed for different purposes, they are systematized according to certain criteria:

I. By design or by size and method of covering the tooth:

1) complete, that is, covering all surfaces of the tooth;

2) equatorial, that is, reaching the equator of the tooth;

3) crowns with a pin;

4) telescopic crowns;

5) fenestrated or fenster crowns.

II. Manufacturing method:

1) stamped;

3) soldered (seam) - now they are practically not used.

III. Depending on the material:

1) metal (gold alloys, stainless steel, cobalt-chromium alloys (CCS), silver-palladium, titanium);

2) non-metallic (plastic, porcelain);

3) combined, that is, lined with plastic, porcelain or other ceramic masses (metal-plastic and metal-ceramic).

IV. By appointment:

1) recovery;

2) supporting (in bridges or other types of prostheses);

3) fixing (for holding medicines, orthodontic or maxillofacial devices);

4) splinting;

5) temporary and permanent.

2. Indications for the use of artificial crowns

1. An unconditional indication for the use of artificial crowns is a significant destruction of the tooth due to caries, its complications or other causes. That is, in other words, the indications are those defects in the crowns of the teeth that cannot be eliminated by a filling or inlay.

2. In some cases, metal crowns are used to cover the teeth, which serve as a support for clasps, especially if it is necessary to change their clinical shape.

3. For fixation in the treatment of bridges, i.e. abutment crowns.

4. With pathological abrasion to prevent the development of further abrasion.

5. With an abnormal shape, color, structure of the teeth.

6. For attaching various orthodontic or maxillofacial appliances.

7. For splinting in case of periodontal diseases and fractures of the jaws.

8. To hold medicines.

9. Aesthetic indications (porcelain, plastic and combined crowns).

3. Contraindications

1. The presence in the oral cavity of teeth with untreated foci of chronic inflammation in the region of the marginal or apical periodontium.

2. Significant mobile teeth.

3. Covering intact teeth with crowns, if this is not related to the design features of dentures.

4. Disease of the cardiovascular system in the acute stage.

5. Mental illnesses and diseases of the nervous system during the acute period.

4. Clinical and laboratory stages of prosthetics with stamped crowns

artificial tooth crown prosthetics

The quality of prosthetics with stamped metal crowns is determined by strict compliance with the requirements that apply to each clinical and laboratory stage.

The first clinical stage is the preparation of teeth and taking impressions.

The preparation of a tooth for a full metal stamped crown consists in grinding all five surfaces.

Tooth preparation begins with separation, that is, the separation of the tooth from the adjacent one. In order not to damage the neighboring tooth, the separation is carried out with a one-sided separation disc. A double-sided separation disc can be used to cover adjacent teeth with crowns.

The hand that holds the tip of the drill with an abrasive tool must be stable. This is achieved by holding the tip with three fingers of the right hand, like a pen, and resting the fourth and fifth fingers on the patient's teeth and chin. At the same time, the left hand, which holds the dental mirror, pushes back the soft tissues of the cheeks, lips, tongue or tissues of the floor of the mouth, protecting them from possible damage.

The separation is carried out in such a way that the proximal surfaces become parallel.

Then the occlusal surface or cutting edge is ground down to the thickness of the future crown (0.25 mm). The preparation of the chewing surface is carried out without significantly disturbing the surface relief, cutting off the tubercles and at the same time deepening the grooves. The contours of the medial and distal angles of the cutting edge of the anterior teeth are preserved.

Sharp angles that form after separation between the buccal and proximal surfaces are smoothed out by shaped heads. As a result of the preparation, the perimeter of the tooth in the cervical area should be equal to the perimeter of the chewing surface or incisal edge, while maintaining the anatomical shape of the occlusal surface or incisal edge. The control of the amount of hard tissues that are removed is carried out using carbon paper composed in 16 layers. This approximately corresponds to the thickness of the crown - 0.25-0.3 mm

After preparing the tooth for a stamped crown, it is necessary to obtain an impression that gives an exact imprint of the prepared tooth. Impressions are taken from both jaws. This allows the technician to fix the plaster models prepared after impressions in the articulator and easily navigate the relationship of the prepared tooth with its antagonists. The impression of the entire dentition allows the technician to evaluate the shape of the dentition, the position of each tooth on the alveolar process, and it is easy to install models in the position of central occlusion. In addition, the technician can facilitate the design of an artificial crown, especially when there is significant decay of the prosthetic tooth. Partial impressions are not suitable for this purpose.

The impression for the manufacture of stamped crowns is usually removed with plaster. Its use allows you to get a fairly accurate print, but requires certain skills. For the same purpose, other impression materials are also used - stomalgin, upin, etc. The so-called double impressions have special accuracy. Thermoplastic masses are not used for these needs, because they give braces and distort the shape of the tooth.

After the impressions of the upper and lower jaws obtained in the clinic, plaster models are cast (the first laboratory stage), which the dental technician makes in the position of central occlusion and fixes in the articulator or occluder, checking the degree of separation of the prepared tooth from the antagonists.

The second laboratory stage is the manufacture of a stamped metal crown. After that, the contours of the neck of the tooth are outlined with an eye scalpel. Engraving is carried out carefully to avoid damage to the cervical part of the tooth. The contours of the gingival margin should be clearly defined along the entire perimeter of the neck of the tooth. A sharply cut chemical pencil outlines the clinical neck of the tooth. The resulting line will serve as a guideline for determining the length and width of the edge of the crown, as well as the degree of immersion of its gum pocket.

Restoration of the anatomical shape of the tooth (modeling) is carried out by gradual layering of molten modeling wax on all surfaces of the gypsum tooth stump. To obtain the first layer, boiling wax is poured onto the stump of a plaster tooth. The plaster model is held with the base up, and the tip of the spatula with boiling wax is applied at a slight angle to the surface of the tooth from the neck to the cutting edge or chewing surface. This prevents melted wax from getting into the neck area and maintains the accuracy of its contours. Further, by layering the melted wax on the surface of the plaster tooth, they achieve an increase in the volume necessary to restore the anatomical shape. The chewing surface is modeled behind the antagonist teeth. The modeled tooth should be smaller than the future crown by the thickness of the metal (0.25-0.3 mm).

After the resumption of the anatomical form with wax, a plaster stamp is started to be made and replaced with a fusible alloy stamp. To do this, the modeled tooth is cut out of the plaster model with a jigsaw or plaster knife so that the surfaces of the so-called root part of the plaster die are parallel to the longitudinal axis of the tooth. Then, standing 1 mm away from the line of the clinical neck of the tooth and parallel to it, a groove is made with a depth of 0.5 mm. This groove serves as a guide to determine the length of the edge of the metal crown.

Plaster stamps are used to prepare metal stamps. To do this, the cut plaster die is immersed in water for 5-10 minutes, after which the plaster is kneaded, poured into a rubber ring with a diameter of 3-4 cm and a height of 4-5 cm (if 1 crown) - they are immersed strictly vertically and exactly in the center of the rubber ring ; plaster is placed in an even layer on the table or poured into special frames (moulds) (if there are several crowns) and the plaster die is immersed exactly halfway into it with the proximal surface.

The hardened gypsum block is pushed out of the rubber ring. On two opposite sides, wedge-shaped longitudinal grooves are made, oriented to the plaster stamp so that the fracture line passes strictly through its middle. After the gypsum stamp is released, all parts of the gypsum counter-mould are made up, placed in a rubber ring and filled with molten low-melting alloy, which is melted in a special spoon. For the manufacture of one artificial crown, two metal stamps are cast. The first, as the most accurate, is used for final stamping, and the second, less accurate, due to the loss of pieces of plaster counter-form during its re-compilation - for the previous stamping. The loss of pieces of a plaster counterform during the preparation of its parts leads to the formation of irregularities on the surface of the metal stamp, which are removed with a file.

In accordance with the diameter of the crown of the metal stamp, a metal sleeve is selected. To do this, use a special device for prosthetic sleeves (apparatus "Samson").

A properly selected sleeve should be put on the stamp with some effort.

The previous processing of the sleeve is carried out on a dental anvil, which has a number of punches with different tooth shapes. To do this, on the anvil, first round the edges of the sleeve on a round punch. Then, on the second punch, the sleeve is shaped into the corresponding tooth. To restore the properties of the alloy after pulling the sleeves (plasticity, ductility), they are subjected to heat treatment. The steel sleeve is heated to a temperature of 700-800°C, followed by cooling to room temperature. To prevent the formation of wrinkles on the sleeve, the hammer blows should be directed from the chewing surface to the edge.

To accurately recreate the chewing surface or incisal edge of a metal tooth in a socket, a separate technique can be recommended. The coronal part of the metal tooth is wrapped with one layer of adhesive plaster, leaving the occlusal surface free. A molten fusible alloy is poured into a metal cuvette 1.5 cm high and 3 cm in diameter with a catheter-like recess and a metal stamp is lowered into it with the chewing surface down to a depth of 1-2 mm. After the metal is approved, the tooth is easily removed, and the resulting image of the chewing surface is used for preliminary stamping occlusal surface of the crown. To do this, after removing the adhesive plaster from the stamp, a pre-stamped sleeve is hammered onto it and hammer blows are hammered into the recess of a plate of low-melting metal. By hammer blows, the sleeve is given an approximate shape of the future crown, achieving its tighter fit to the entire surface of the metal stamp. This completes the pre-stamping of the crown, which is carried out on the second die. Before the final stamping, the sleeve is again subjected to heat treatment in the same mode, and the first stamp is prepared for final stamping by an external or combined method.

Parker External Stamping Method

Parker's apparatus consists of two parts of a hollow base and a cylinder located in it, the outer end of which is a massive smooth platform. The base cavity is filled with molding or unvulcanized rubber. For the same purpose, mechanical, hydraulic or pneumatic presses can be used, which facilitate and speed up the process of stamping crowns. The annealed sleeve is put on a control metal die and placed with the coronal part inside the mass. By hammer blows on the cylinder, stamping is carried out. At the same time, molding or rubber act as a counter-stamp, which evenly transfers pressure in all directions, and contributes to a snug fit of the crown to the surface of the metal stamp.

Method of internal stamping of crowns

To understand the essence of the method of combined crown stamping, you need to have an idea about the method of internal stamping, which is currently not used due to complexity and insufficient accuracy.

For internal stamping, an apparatus is used that consists of three parts: a massive steel cuvette with protrusions inside to facilitate the splitting of a low-melting metal counter-stamp, a support for removing fusible metal from the cuvette and a rubber cone that makes up the bottom of the cuvette from a metal pin to strengthen the plaster tooth.

stamping technique. First, a plaster stamp with a ring is fixed on the pin, then a cuvette is placed on the cone and filled with metal. After that, the metal is removed, it is split between the counterstamp halves and introduced into the cuvette. The sleeve is filled with shot or soft rubber and driven inside the metal mold, first with wooden sticks, then with metal rods.

Combined crown stamping method

This method combines elements of external and internal stamping and is therefore called combined. The apparatus consists of a steel cell, the inner surfaces of which are brought into a cone and have two protrusions in the middle of the line, which facilitate the splitting of the counterstamp. The cuvette has a support in the form of a metal ring. The bottom of the cuvette has a hole with a diameter of 1 cm to remove the counterstamp from the cuvette. To center the metal stamp in the cell, a holder is added, which, fixing the stamp, is installed in the central notch of its upper surface.

stamping technique. The previous stamping is carried out in the manner described above to the second die. A metal counterstamp is obtained in this way. The first stamp is covered with a layer of adhesive plaster, leaving the chewing or palatal surface and the cutting edge open. Then, a molten low-melting alloy is poured into a special cuvette, the inner surface of which is brought into a cone, and a die covered with a plaster is immersed in it with the chewing surface down. After the metal hardens, it is taken out together with the die and split into 2-3 parts. A patch is removed from the metal counter-stamp, an annealed sleeve is put on it and inserted into the bed of the assembled counter-stamp, which is then placed in a cuvette and the crown is stamped with hammer blows, first on parts of the counter-stamp, and then on the stamp.

After stamping, the stamped crown is removed from the metal die by heating the latter. The crown is cut along the borders in the cervical area, put on a plaster die and transferred to the clinic for fitting.

The second clinical stage is the fitting of crowns. A properly made and fitted crown tightly covers the neck of the tooth and is often difficult to remove from the tooth. Then they take some cotton wool, cover the crown with it, grab the crown with one or two, and the molar with three fingers of the hand and with careful movements try to move the crown alternately in the vestibulo-oral direction. If it is not possible to remove the crown in this way, it is removed with the help of tools. To do this, use a spatula for mixing cement or a dental spatula. It is more convenient to use the special Koppa crown remover.

The third clinical stage is the fixation of the crown in the oral cavity.

The stamped metal crown tested in the patient's mouth is again transferred to the dental laboratory for polishing.

Before applying to the oral cavity, it is thoroughly washed with hydrogen peroxide and disinfected with alcohol. The abutment tooth is covered with cotton swabs and subjected to medical treatment. The tooth surface is thoroughly disinfected with alcohol and dried with ether. Best results can be achieved by drying with warm air, which is supplied through a special handpiece of the drill.

On a pre-prepared sterile glass plate (lash), a fixing cement of a liquid consistency is kneaded. The rules for preparing cement and its consistency depend on the brand and purpose to be achieved when strengthening the crown.

The prepared cement is introduced into the crown with a clinical spatula, filling it approximately one third. The inner walls are coated to the edges of the crown. The crown with cement is put on the tooth, making sure that cotton swabs do not fall under the edge of the crown. To do this, it is useful to fix them with the fingers of the left hand at a certain distance from the neck of the tooth, and to put on a stamped crown with the right hand.

After applying the crown with cement, it is necessary to immediately check the occlusal relationship according to the central occlusion. If the crown is in close contact with the opposing teeth, patients are asked to keep their teeth closed for 10-15 minutes until the cement sets.

Remains of cement are carefully removed from the surface of the crown and adjacent teeth. Particular care must be taken to remove the cement that fills the interdental spaces. Remains of cement on the surface of the polished crown can be easily removed with a cotton swab soaked in phosphate cement liquid. After removal of residual cement from the surface of the tooth, the patient is advised to keep the teeth closed for another 1-2 hours until the fixing material has completely hardened.

Bibliography

1) Konovalov A.P., Kuryakina N.V., Mitin N.E. Phantom Course in Orthopedic Dentistry / Ed. prof. N.V. Trezubova. - M.: Medical book; N. Novgorod: Publishing house of NGMA, 1999. - 344 p.

2) www.stom-portal.ru

Hosted on Allbest.ru

...