Dental inlays: Inlay, Onlay, Overlay. Their role in eliminating defects in hard dental tissues

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The possibilities of modern dentistry make it possible to save even a fairly badly damaged tooth, replacing the radical method of eliminating the problem, that is, removing the organ, with a more gentle procedure - its treatment through the use of fillings and inlays.

They allow you to return the tooth to its original functionality and qualitatively improve its aesthetics. And if everything is more or less clear with filling materials, then the use of inlays raises a number of questions among patients.

What kind of devices are these, what they are made of and how they are used - this will be discussed in this article.

General overview

Dental inlays are orthopedic micro-prosthetic structures that replace cavities in the crowns of damaged teeth.
As a result of the restoration, the organs acquire an anatomical shape and relief that is as close as possible to nature. In fact, this is another type of filling, but the only difference is that the production is carried out outside the patient’s mouth , and in the laboratory using a plaster cast.

This process allows you to get rid of shrinkage of the composite material , which inevitably occurs during classical filling.

Also, using the tab, it is possible to recreate an exact copy of the missing fragment of a destroyed tooth. All the tubercles on the surface of the product perfectly follow the contours of natural elements.

Microprostheses are characterized by a fairly strong macro and microstructure, which is resistant to abrasion. The products are installed already formed, while the filling material has a plastic consistency.

Inlays are a more progressive method of restoring the integrity of teeth. They provide longer and more stable operation compared to standard treatment.

Advantages and disadvantages

Practice shows that the use of inlays for prosthetics provides a number of advantages, including:

Strong connection between the microprosthesis and the base, determined by maximum contact of surfaces;
The possibility of using products to correct interdental gaps that arise due to the development of pathologies or congenital defects, as well as age-related changes in the body;
Prevention of caries development - a positive effect occurs due to the absence of shrinkage and preservation of the full structure of the tooth, eliminating the accumulation of bacteria;
Duration of operation of products that are resistant not only to mechanical loads, but also to the effects of coloring elements contained in food and drinks.

Speaking of disadvantages, it is worth mentioning that composite inlays cannot be repaired if damaged. Any chips and cracks that appear in the structure of the microprosthesis are the basis for its replacement. In addition, the technique is more expensive than the traditional installation of fillings, which is determined by the aesthetics and functionality of the installed products.

Product advantages

The use of inlays for dental reconstruction has several undeniable advantages that make the use of this technique optimally preferable in comparison with other restoration methods:

Precise connection . Fastening of the microprosthesis with the hard tissues of the coronal part is guaranteed by the ideal abutment of the walls of the structure.
Tabs are more reliable and durable than, for example, a filling . To create it, materials are used (ceramics, metal alloys), which in all respects are comparable to enamel.
High-quality reproduction of interdental segments, cusps, depressions, angular coronal zonal surfaces, taking into account the age and anatomy of natural units.
Wear-resistant. This is possible due to the compliance of the load indicators with the requirements for this element.
The material does not shrink . It is precisely because the filling tends to shrink over time that they often fall out, which never happens with inlays.
Durable . The service life of structures significantly exceeds that of conventional fillings. The average duration of operation is 8-10 years.
Convenient to install . During the placement of microprostheses, the patient does not need to constantly keep his mouth open so that saliva does not penetrate into the treated cavity. They fix quickly in a few minutes.
Retains shade . Even after a long period of time, the tabs do not darken and cannot be stained with food coloring.
They are the prevention of recurrent caries . Achieved due to the absence of shrinkage during operation, the ability to maintain original parameters and complete edge contact.

Manufacturing Features

For good retention, the walls of the inlay should be approximately parallel. A carious cavity never has this shape. There are almost always undercuts. When placing a filling, the filling material is introduced into the cavity in a plastic form, so undercuts not only do not pose any problem, but on the contrary, they help to retain the restoration that subsequently hardens. The inlay must be placed in the prepared cavity in a solid state, so undercuts must be eliminated. This can be done in two ways: either remove healthy tooth tissue above the undercut, or fill the undercut with filling material. The first option is cheaper, but more invasive. The second increases the cost of treatment, but treats the tooth as carefully as possible.

Ceramic inlays can be made by two methods: layer-by-layer application of ceramics or painting a monochrome block. The first option is more aesthetically pleasing and more expensive. Just as in your own tooth, different layers of enamel and dentin have a personal color, so in the inlay made in this way, their color is recreated. A painted inlay can also look very nice, but it requires a very colossal talent of a dental technician. CEREC inlays are machined from a factory-made block of ceramic and then painted. A dentist can, of course, succeed in this matter better than a dental technician, but still these are two different professions, and there are few such unique people who can work equally well as both a doctor and a dental technician. If the patient’s requirements for the aesthetics of the inlay are low and there is a shortage of time, the CEREC inlay can be called the optimal choice.

Stump inlays are either monolithic or collapsible (composite). Collapsible inlays are made for multi-rooted teeth. An additional pin, not parallel to the insertion path, significantly increases the retention of the core insert. But the need for its use does not arise so often: in molars, even a single-pin inlay is most often retained well, and in premolars, the divergence of the canals is in most cases weakly expressed or absent. Using the third and fourth pins is completely irrational. For a stump inlay, the most important parameter is the length of the intracanal pin. A stump with a short post often becomes uncemented and can fracture the root. The optimal length of the pin is from 1/2 to 2/3 of the length of the root and not less than the height of the intracoronal part of the stump tab.

Flaws

The primary disadvantage of microprostheses is the impossibility of repairing them. If the material is partially destroyed or chipped, the tab must be replaced with a new one.

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In addition, the design disadvantages include the following characteristics:

high cost of installation (compared to conventional filling);
other specialists are additionally involved in the process, for example, a technician;
It takes more time to complete the entire complex of recovery manipulations.

It is also necessary to consider the professional factor - incorrect work of the doctor increases the likelihood of complications such as inflammation, tissue infection, poor adhesion of the inlay to the tissues.

What are the inlays made of?

Composite inlays are also easy to manufacture, quickly installed and allow you to accurately select a shade that matches the color of the tooth being restored.
Metal, composite material or ceramics are used to make microprostheses. They all have their own characteristics:

Metal tabs are durable and easy to manufacture. They can serve for decades. But their aesthetic characteristics are low, so these designs are used only on teeth located deep in the mouth.
Composite inlays are also easy to manufacture, quick to install, and allow you to accurately select a shade that matches the color of the tooth being restored. They are not as durable as metal ones, but if damaged they can be repaired right in the mouth.
The most promising type of dental prosthetics with restorative inlays involves the use of ceramics as a manufacturing material. The professorial clinic “22nd Century” installs durable ceramic inlays with stable aesthetic properties. They are practically indistinguishable from the rest of the tooth surface.

Classification

There are several types of dental inlays, depending on the parameters, range of applications, and structural content.

Based on specific characteristics, all occlusal devices are classified according to three main criteria:

restorative - devices that bring the chewing load applied to the periodontal fragments back to normal;
loading - used as incomplete replacement of elements of the jaw row. Serve as support for bridge-like prosthetic structures;
distributing – normalize mechanical pressure during fragmentary splinting of organs.

According to the topography of the defect

The main factor that negatively affects the position of the coronal area of the tooth is carious processes. That is why dividing the disease according to the principle of topography is important from the point of view of microprosthetics.

Within this classification, all pathologies are divided into 6 classes. This simplifies the specialist’s work. Having determined the class affiliation of the clinical situation, it is enough to simply identify the specifics of cavity formation, provide optimal conditions for attaching the lining and eliminating the risk of developing secondary caries.

Letter designations

Cavity diagnosis proceeds more easily using alphabetic symbols according to Boyanov’s method:

O – cavity localized on the chewing surface;
M – medial cavity;
D – damage to the distal zone;
MO is a complex clinical picture in which the cavity partially involves several surfaces. In this case – medial and chewing;
MOD – lesions of all superficial segments.

By design

Based on the degree of damaging effects of caries manifestations on the coronal zone of the tooth, for high-quality replacement of elements of destroyed tissues, the following design options for inlays are distinguished:

Inlay is a system fixed in the central region of the less invasive part of the organ, preserving the tubercular integrity of the relief;
Onley is a prosthesis that affects the superficial slopes by applying overlays to the tubercles;
Overlay is a device that, with its parameters, can completely cover internal slopes and uneven terrain with an overlay;
Pinley – a device that is securely fixed inside the cavity using special pins located in hard dental areas.
During the production of such microprostheses, all tubercles are completely covered.
On the frontal elements it is possible to manufacture a pin while maintaining the integrity of the cutting edge segment and vestibular relief. Visually, such structures resemble a half-crown pin model.

By material

To produce structures, dental technicians use the following materials:

titanium alloys;
gold;
plastic - acrylic and semi-acrylic components, as well as derivatives of the nylon series;
ceramics - made on the basis of zirconium, titanium oxides, standard porcelain composition;
combined - include metal-composite compounds and ceramic-containing metal mixtures.

Dental inlays inlay, onlay, overlay

Dental inlays inlay, onlay, overlay, which are types of microprostheses, are the optimal way to restore damaged tooth crowns.
The materials used, as well as the methods of manufacturing and installation of such structures provide a number of advantages of their use compared to traditional methods of treatment. The use of inlays in dentistry is one of the progressive methods of restoring damaged teeth. A dental inlay is an orthopedic micro-prosthetic structure installed to replace the damaged or lost crown part of a tooth. By creating tubercles of the chewing surface, specialists achieve compliance with the natural anatomical shape and relief. This method, which in its purpose is between the use of a filling and a complete crown replacement, combines reliable restoration of the integrity of the teeth with the absence of radical intervention. Depending on the degree of destruction of the crown, the following design options for inlays are distinguished:

Inlay (inlay tab) is the least invasive system, fixed in the central area and does not affect the tubercular integrity of the tooth relief;
Onlay - a more voluminous prosthesis that affects the internal slopes of the masticatory tubercles;
Overlay is a product that completely covers the chewing tubercles.

Inlay onlay and overlay tabs will be a reliable replacement for fillings and will restore the aesthetics of your teeth.

Installation of ceramic inlays occurs in several stages

During the first visit, the patient’s teeth are prepared for filling: carious tissue is removed, a cavity is formed for the inlay, and an impression is taken.

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Using impressions, the dental laboratory first makes a model of the future filling, and then the ceramic insert itself. The process consists of layer-by-layer application of the material, periodic firing and subsequent polishing of the formed inlay.

During the second visit, the patient is fitted with and then glued into the prepared area, and the interface between the ceramic and the tooth surface is carefully polished.

Ceramic dental restoration is often the only opportunity to reconstruct a seriously damaged tooth in the most gentle way. Using ceramic inlays, you can increase the life of your teeth and avoid having to install crowns.

The creation of special adhesive compositions - the so-called adhesives - has brought dental restoration to a completely new level. Adhesives allow you to glue filling materials made from a wide variety of materials, including ceramic inlays, to the tooth surface.

The use of ceramic inlays, glued with adhesives, has become an ideal replacement for conventional fillings - especially for patients with severe tooth decay, when conventional filling is not possible, for example, when the pulp is damaged.

Restoration ONLAY.OVERLAY.INLAY

These are types of “fillings” made not in the oral cavity, but in the laboratory on a plaster model. Since production occurs outside the oral cavity, all the disadvantages inherent in the direct method disappear - the absence of stress shrinkage, the ideal, correct anatomical shape of the tooth, achieved by building based on the shape teeth of the opposite jaw. These onlays have an ideal, indelible macro and microstructure, where each cusp and fissure is built in the correct physiological place, which ultimately leads to the full chewing efficiency of the tooth. They have an ideal stable color and shine that does not disappear over time.

ONLAY OERLAY INLAY - can be made of reinforced composite material, ceramic and gold. Which material is better?

The best material in all respects except aesthetics is gold. Due to the plasticity of gold, the linings made from it are rolled over the edges of the tooth, enveloping them, thus strengthening and preventing microorganisms from penetrating into the thickness of the tooth. In the past, composite fillings replaced gold from dentistry, now gold is returning and for those patients who want the most long-term treatment results, “gold fillings” are the best treatment option.

In second place in terms of longevity are ceramic linings - their main trump card is ideal aesthetics and the shape of macro and micro relief, but unlike gold, ceramics do not have plasticity. But this disadvantage is compensated by the ideal manufacturing precision. Ceramic onlays currently make up 90% of all onlays manufactured in our clinic.

In the last place we placed occlusal linings made of composite reinforced material - in essence, this is the same filling material from which fillings in the oral cavity are made. But laboratory production allows us to talk about complete polymerization of the material using powerful laboratory lamps in a vacuum environment. And the shrinkage inherent in all composites is eliminated when the onlay is glued to the tooth. Of course, this type of onlay is much better than a direct filling, but due to the high price, which is close to ceramic onlays, we do not produce this type of restoration (composite occlusal onlays) in our clinic. Our alternative to fillings is OVERLAY, INLAY, ONLAY onlays made of gold and made of pressed ceramic E.Max

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Installation and operation of dental inlays

The procedure for such dental prosthetics takes place in two stages. At the first appointment, the patient’s teeth are prepared: removal of carious tissue, preparation for an inlay onlay overlay, taking an impression. Based on the impressions, the dental laboratory makes the prosthesis. During the second visit, the doctor glues the already formed structure using special adhesives - so-called adhesives, and the seam is thoroughly polished.

For the production of microprostheses, onlay inlay overlay, metals (titanium alloys and gold), plastic (acrylic, etc.), ceramics (based on zirconium, titanium oxides, standard porcelain composition), combined materials (metal-composite compounds and ceramic-containing metal mixtures) are used. Ceramic inlays are the most in demand and most often used (in 80% of cases) due to their greater compliance with the characteristics of tooth enamel. The strongest and most durable are gold products, the average service life of which is 8-10 years. A long service life is also ensured by: the professionalism and quality of work of dentists, the patient’s compliance with the rules of hygiene, care and wearing of the device.

What are the alternatives?

If there is a volumetric lesion of the coronal part of the tooth, there are only four options for prosthetics. The first is the tabs themselves. The second is filling, but a large filling may not withstand the load, and there will be too few tooth walls for the composite material to adhere to, so it will be short-lived. The third method is to install a crown. But this option is an extreme option, when other methods are no longer effective. The fourth method is tooth restoration on a pin: a metal rod is installed inside the root, which serves as a support for restoring the coronal part (using an artificial crown or composite build-up). This option is cheaper, but less durable, and the pin can lead to root fracture.

Indications for installing inlay, onlay, overlay tabs

The use of ceramic and other onlay inlay overlay tabs is the best option in a number of cases:

restoration of relief with a high percentage of destruction;
treatment of caries in those clinical situations when other methods of therapy are not suitable;
replacement of old and bulky fillings;
treatment of hard tissue pathologies not related to caries;
creation of supports for prosthetics and the formation of bridge structures;
creation of splinting systems for the treatment of periodontal lesions.

The use of overlays and inlays is not advisable for mild carious lesions or, conversely, for significant destruction of the crown, for violations of the structural composition of tooth tissues, and for difficult access to cavity fragments.

Tabs lifespan

How long the inlays will last depends largely on the initial condition of the tooth. If a sufficient number of supports have been preserved to fix the prosthesis (that is, not only the base of the cavity, but also the walls of the tooth), its installation was carried out professionally, then the composite inlay will last from 3-4 years, ceramic or zirconium - from 10 years or more. Proper care of the restored tooth is also important (it is necessary to prevent the development of caries, since in this case the inlay will have to be removed and redone).

Regular care and periodic preventive examinations at the dentist will help extend the service life, the purpose of which is to assess the condition of the tooth and the quality of the fit of the prosthesis.

Indications and contraindications

Factors considered as a basis for inlay restoration include:

The need to restore the structure and topography of heavily damaged units;
Development of caries in circumstances where other restoration methods are ineffective;
The presence of pathologies in hard tissues caused by excessive abrasion, mechanical defects, wedge-shaped anomalies and other factors;
The need to create a base for installing a bridge;
Using a tab as an element when creating and placing a splinting system.

Among the limitations that exclude the possibility or cast doubt on the feasibility of restoration using this technique are:

Minor damage to dental tissue by caries;
The destruction index of IROPZ is over 0.6;
Changes in the natural structure of the tooth, leading to fragility;
Location of cavity fragments in hard-to-reach areas.

Prices

The average cost of a tab is determined by the material from which it is made.

Analyzing the pricing policy of many dental clinics that provide services for the restoration of hard dental tissues with microprostheses, the cost looks something like this:

Material	Average cost in thousand rubles. (for 1 piece)
metal	From 8
plastic	From 6.5
ceramic	From 17
combined	From 12

The process of manufacturing and installing inlays on a tooth

Dental prosthetics is performed in several stages:

Initial consultation
. The doctor assesses the extent of destruction and draws up a recovery plan;
Hygienic teeth cleaning
if necessary;
Selection of the required shade
to match the enamel color;
Removal of tissues affected by caries
, if the destruction was caused by this disease;
Taking an individual impression
, according to which a microprosthesis will be made;
Closing the cavity with temporary material
for the waiting period;
Making an inlay
based on an individual impression in a dental laboratory;
Installation
of the inlay and its fixation using special dental cement.

Thus, a tooth can be restored in 2 visits to the clinic. The first visit is a consultation, treatment of caries and taking an impression, the second is the actual installation.

Reviews

Restoration of damaged teeth with inlays is classified by dentists as the most gentle treatment method. Despite the high cost, its effectiveness is high if there are indications for it.

If you have experience with such treatment and would like to express your opinion on its effectiveness and feasibility, please share your feedback in the comments to this article.

Sources:

https://zubovv.ru/protezirovanie/nesemnyie-p/vkladki/inlay-onlay-overlay.html
https://smile-at-once.ru/uslugi/vkladki.html
https://www.vash-dentist.ru/protezirovanie/nesemnyie-p/vkladki/inlay-onlay-overlay.html
https://doctorhollywood.ru/keramicheskie-vkladk
https://galadent.ru/protezirovanie/vkladkikeramicheskieonlayinlayoverlay

Different types of tabs and their comparison

An inlay is a microprosthesis that allows you to restore the anatomical shape of a tooth in case of damage to the coronal part. In essence, this is a filling created in the laboratory, but these two options have a clear difference: the filling material is introduced into the cavity in a soft state, and the inlay is in a hard state. A stump inlay with a pin is a simple but at the same time effective design.

Due to this factor, many advantages can be achieved:

– the mating surfaces are connected accurately, without gaps and cavities with air, which significantly weaken the structure;

– the scope of application of inlays is wider, due to the possibility of restoring areas between teeth, including in places where units come into contact, it is possible to work on complex elements, such as the corners and cusps of crowns, including the age and individual characteristics of each client;

– the characteristics of the material exclude relapses of caries, since there is no shrinkage after restoration, the volume of the element and an exact fit to the edge of the cavity being covered are preserved;

– mechanical strength is high, the surface is wear-resistant and maintains performance at a high level throughout the entire service life;

– in laboratory conditions it is possible to form a substance with maximum density, thereby preventing the penetration of coloring substances from food into the structure. This allows you to achieve a stable color, and also eliminates the possibility of pockets of development of potentially dangerous microorganisms.

No less complex in terms of manufacturing method is the zirconium dioxide abutment, which is mainly created as an individual restoration. A single-root tab is simpler for obvious reasons.

Due to this factor, many advantages can be achieved:

“Pin-stump inlays” (synonyms: “SHKV”, “Intraroot inlays”, “VKV”)

These are structures used to restore severely damaged teeth. With their help, a “tooth stump” is recreated, which is subsequently covered with an artificial crown. That is, in this case, the inlay is an intermediate stage in the manufacture of another non-removable orthopedic restoration - the tooth crown.

Comment: Intraroot inlays restore the tooth stump, which is covered with an artificial crown.

A pin-stump inlay is an excellent design that restores severely damaged teeth. In many cases, it is the only and last opportunity to do this. Once fixed with permanent cement, it cannot be removed from the tooth. If problems arise (crown decementation, root fracture, etc.), the tooth restored with an inlay often has to be removed. In the future, the missing tooth can be replaced with a bridge or an implant-supported crown.

Indications for installation

Teeth, under the influence of various factors, are destroyed, subject to caries, injured, or even need to be removed. When fillings and other methods of eliminating defects are not possible, crowns are placed.

This is one of the types of prosthetics. With the help of a non-removable structure made of special materials, pronounced anomalies are eliminated.

Severe destruction of one or more teeth due to extensive caries or trauma with preservation of the root – 70% of all cases. It is necessary to prevent splitting of the base and correctly distribute the chewing load;
The presence of pathological abrasion of enamel. All teeth are preserved, but protection from surrounding negative factors is required;
Periodontal disease resulting in noticeable loosening. Stability is achieved using temporary crowns;
Installation of a bridge structure: crowns for support can be fixed to healthy teeth;
Unsightly appearance caused by defects or significant discoloration of the enamel.

The decision in which cases to place a crown on a tooth is made based on the results of an individual consultation with a dentist. As a rule, in addition to examination, an x-ray examination is required.

Who should not get crowns?

There are no strict restrictions on installation, but there are a number of points that must be taken into account. If your own tooth crown is not high, then it will first have to be built up. And in the case of weakened periodontal disease and unstable teeth, it is first recommended to carry out a course of therapeutic treatment and only then carry out prosthetics.