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.

Materials

Gold is the best inlay material for patients without aesthetic needs. Reliability and durability have been proven over more than a century of use. Soft, high-carat gold is used for the inlays. This gold is rolled around the edges of the restoration, preventing bacteria from penetrating into the target between the inlay and the tooth. Ceramics is a material with excellent aesthetic properties. However, it is fragile - requiring more tooth preparation (compared to gold) to reduce the risk of fractures and chips (which can occur from time to time). Like gold, ceramic inlays are not quite cheap. Feldspar ceramics, E.max, zirconium oxide are the most common components of ceramic inlays. Composite is a less expensive material with good aesthetics. Its hardness is lower than that of ceramics and the enamel of your own tooth - therefore, such inlays wear out more over time. May slightly lose color (darken) over time. Due to less fragility, chips are less common (than with ceramics). Ceramic composite is a combined material whose properties are closer to a composite than to ceramics. Hardness and color stability are higher than composites, but lower than ceramics.

Stump inlays can be metal (gold, cobalt-chromium, nickel-chromium, silver-palladium and other alloys), ceramic (zirconium oxide) and combined (metal lined with ceramics). Metal stump inlays are the strongest and most durable. There is no significant difference between the alloys. For more information about the properties of dental alloys, see Selecting an alloy for a metal-ceramic crown. In terms of price/quality ratio, the optimal material for stump inlays is chromium-cobalt alloy. Simply the best (if you don’t pay attention to the price) is gold.

Compliance with indications, correct form and manufacturing accuracy have a much greater influence on the success of the restoration than the metal ingredient. Stump inlays made of zirconium oxide and metal, lined with ceramics, are positioned as a necessity to create a stump that matches the color for subsequent tooth restoration with an all-ceramic crown. But nowadays it is not a problem to cover a metal stump with a metal-free crown, creating excellent aesthetics. Stump inlays made of zirconium oxide are extremely unpleasant because they can break, and it is extremely difficult to get broken pieces of the pin in the canal. For more information, see the article Why zirconium oxide inlays are contraindicated.

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.

Advantages of inlay onlay ceramic inlays

Compared to filling, the use of inlays allows you to:

qualitatively restore the features of the relief, taking into account the anatomical and age-related features of the structure of the teeth;
achieve strength and reliability of the connection with a perfectly precise fit of the inlay material to the tissues of the living tooth;
ensure wear resistance and durability of the structure, using materials that form a durable structure;
carry out effective prevention of recurrent caries due to the absence of shrinkage of the product during operation;
provide an aesthetic appearance: inserts are difficult to distinguish from natural fabrics, the structure of the material makes the color of the product resistant to coloring pigments.

As a consequence of the above-described advantages, this procedure has a higher price, takes more time and requires the involvement of additional specialists. Among the disadvantages is the impossibility of repairing the structure (only replacement).

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.

Manufacturing technology

For the manufacture of inlays (like any other laboratory structures) a minimum of 2 visits is required. CEREC tabs are no exception, only both visits occur on the same day (1-2 hours apart). On the first visit, the doctor prepares the tooth, takes impressions, and installs a temporary filling or inlay. In the second, the finished restoration is tried on in the mouth, adjusted, and, if the doctor and patient are completely satisfied with it, fixed with cement. If you don’t like something, the tab is returned to the dental laboratory for revision (the CEREC tab is corrected by the dentist himself), and its delivery is postponed to the next visit. Making a stump inlay can be done in exactly the same way, but the doctor himself can model it directly in the mouth from plastic or wax. Then the stage of taking impressions is not needed; in the laboratory, the stump inlay will be made according to the obtained model.

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.

Indications and contraindications

Depending on the functional purpose and capabilities of the tabs, direct indications for their use are:

the need to restore the relief with a high percentage of destruction;
manifestations of caries in those clinical situations when other methods of therapy, including filling, will not bring the desired result.
In particular, this is the presence of cavity fragments in the cervical zone of the tooth, sharp edges at the frontal units of the jaw row, as well as pronounced tuberosity and angularity of shapes;
pathologies of hard tissues , the result of which are non-carious lesions - wedge-shaped anomalies, defects due to mechanical trauma, the tendency of organs to excessive abrasion of the enamel surface;
creating support for pins or an artificial stump with a pin during prosthetics;
the need to form a base for bridge structures when the length of the destroyed fragment is no more than three dental units in a row;
as a component of splinting systems in the treatment of periodontal lesions.

Indications for which the use of tabs is impossible or inappropriate:

minor damage to organ tissue by caries fragments;
destructive degree of more than 0.6 with IROPZ indicators;
violations of the structural composition of tooth tissues , leading to its fragility and tendency to discalcification;
difficult access to cavity fragments.

Causes of pathological abrasion of hard dental tissues and ways to eliminate the problem.

In this publication we will talk about metal alloys used in orthopedic dentistry.

Here https://www.vash-dentist.ru/protezirovanie/nesemnyie-p/etapyi-podgotovki-zubov.html detailed information about preparing the oral cavity for dental prosthetics.

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.

This is interesting: Metal-ceramics or ceramics: what is the difference, what is better to choose for installing crowns

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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Terminology

“Tab” is a semantic translation into Russian of the English “inlay”. This is a restoration surrounded by 2-4 walls, with preserved tooth cusps. In a broader sense, tabs also include the English “onlay”, “overlay” and “pinlay”. However, for “onlay” and “overlay” the term “overlay” has recently been more often used. For “pinlay” there is no stable equivalent in Russian yet, since this construction is not widespread. The presence of a pin makes it somewhat similar to the “stump tab”. A stump inlay is a laboratory restoration that restores not the anatomical shape of the tooth, but only the stump for future covering with a crown. For brevity, many Russian dentists also call it simply a “tab.” Therefore, in this article, under the “inlay” we will consider a coronal restoration of the “inlay” type, the stump inlay will be called by its full name, and there is a separate article about onlays. Another special type of tab is the CEREC tab. Its main feature is that there is no dental technician or dental laboratory involved in its production - their roles are assumed by the dentist himself and his office. But according to other characteristics, the CEREC tab is a full representative of this family.

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 the use of restoration tabs

Indications for the use of restorative inlays
Microprosthetics allows you to solve several dental problems .

For example, you can use it:

Fill a large carious cavity.
Increase crown height that is too low.
Avoid depulping a healthy tooth (which is always carried out when installing an artificial crown).
Completely restore the tooth structure and its ability to chew food effectively.
Ensure high aesthetic results of dental treatment.
Reduce the time spent in the dental chair while maintaining the quality of treatment .

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.

Advantages and disadvantages

Some of the positive aspects noted by specialists who use the tab installation technique include:

Strength of fixation of the prosthesis with dental tissue, achieved through optimal contact of surfaces in all areas;
Possibility of high-quality restoration of segments of the interdental area, taking into account the specific anatomical structure and age-related changes in the dentition;
A preventive effect that eliminates the manifestations of recurrent caries, caused by compensatory shrinkage and preservation of the volume of the product;
Long service life, the duration of which is ensured by the resistance of the insert to the influence of food dyes and pigments;
Increased resistance to mechanical wear, preservation of natural shine and reliable protection of dental tissue, which acts as a base for installation.

Among the disadvantages characteristic of dental inlays, it is worth noting the inability to repair a structure that has been subjected to mechanical damage. Chips and cracks cannot be repaired and require replacement of the product. In addition, the manufacture and installation of a composite inlay is more expensive than conventional fillings.

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

Service life

The service life of products largely depends on the material from which they are made. Gold products are considered the most durable.

With high-quality installation and careful use, they will last at least 7-8 years.

Ceramic structures show good performance in terms of durability - they account for more than 80% of all microprostheses.

The following factors can shorten the operating period:

incorrect actions of the doctor during the fastening process;
non-compliance by the patient with the rules of hygiene, care and wearing of the structure;
violations of the structural composition of bone tissue.

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

Scheme of installation of microprostheses

The production and installation of a restorative inlay requires a minimum of two visits to the dentist. At the first stage, the doctor prepares the tooth (removes carious tissue and forms a cavity for the inlay), selects the color of the microprosthesis, makes an impression and then places a temporary filling. During the second visit, the finished inlay is installed on the tooth using special glue and dental cement. After this, the gluing area is polished.

Methods for making restoration inlays

Direct method . The inlay is modeled from wax inserted into the prepared cavity. The impression is then removed from the tooth using a metal pin and sent to the laboratory. There the wax is replaced with the base material.
Indirect (indirect) method . First, a double impression of the prosthetic bed is made. Then, in the laboratory, a plaster structure is modeled, reproducing not only the tooth , but also the jaw. This allows you to try on the insert without the direct participation of the patient. After subsequent fitting of the microprosthesis in the tooth cavity, it is checked and polished.
Computer milling of ceramic inlays . The use of this technology eliminates the clinical (taking impressions) and technical (making models) stages of the process. This saves the time of the doctor, the technician and the patient himself, and increases the accuracy of manufacturing the microprosthesis. Computer milling takes about 15 minutes, so this method of microprosthetics requires only one visit to the dentist.

Composite tabs onlay and inlay

The choice of technique for restorative procedures quite often becomes a cause of doubt, confusion and indecision among dentists. We, as members of the Style Italiano community, firmly believe that in posterior restorations, the direct approach should be preferred whenever possible. But in clinical cases requiring cuspal coverage and multiple cavities involving one quadrant or more, an indirect approach can reduce the time required to model and create correct shapes. All contact areas can be perfectly formed from the plaster model, which will help the clinician solve one of the biggest problems in multi-cavity restorations.

The described clinical case shows how to treat one quadrant with the production of composite onlay and inlay inlays in a modern and simple way.

Image 1 – Picture before the intervention with old restorations that need to be replaced due to secondary caries.

Image 2 – Isolation of the surgical field with a rubber dam.

Image 3 – Removal of caries and preliminary preparation.

Image 4 – After cleaning and disinfecting the dentin, the enamel is etched for 20 seconds.

Image 5 – Adhesive preparation using the 8th generation universal adhesive system, as it has outstanding performance characteristics and simplifies operative procedures. We use the adhesive in self-etching mode.

Image 6 – The adhesive is applied with an applicator into the cavity of each tooth for 20 seconds.

Image 7 – Each tooth is then illuminated for 40 seconds.

Image 8 – Using a fluid volumetric filling composite, we build up the teeth to be restored.

Image 9 – We carry out the final preparation with finishing burs.

Image 10 – Making impressions from polyvinylsiloxane (Imprint 4).

Figure 11 – First, the restorations are fitted without insulation. Then a rubber dam is applied and the teeth are sandblasted with aluminum oxide particles.

Image 12 – Next, we again fit the restorations with the applied cofferdam.

Image 13 – Close-up of the restorations, the internal surfaces of which have also been sandblasted.

Image 14 – Selective enamel etching for 20 seconds.

Image 15 – Application of universal adhesive to both the enamel surface and the composite superstructure areas.

Image 16 – Application of adhesive to the inner surface of the restorations.

Image 17 – Cementation of two indirect restorations with dual-curing cement.

Image 18 – Close-up view of the cementation of the other two indirect restorations.

Image 19 – After sanding, we polish the surfaces using a spiral polishing system.

Image 20 – Anatomy details at the end of the work.

Image 21 – Parts after grinding and polishing.

Image 22 – View after removal of the rubber dam.

Image 23 – Checking occlusion.

Image 24 – Follow-up examination after 2 years.

Image 7 – Each tooth is then illuminated for 40 seconds.

Types of tabs

Depending on the material of manufacture, they come in the following types:

metal-ceramic
- the most budget-friendly;
ceramic
– the most aesthetic;
made of zirconium dioxide
- the most durable.

These microprostheses are also classified depending on their position in the tooth. According to this criterion, the following varieties are distinguished:

Inlay
– the hole in the tooth is box-shaped, the inlay is installed inside it;
Onlay
– the overlay has an external side;
Overlay
– only one wall is preserved, the overlay replaces almost the entire crown;
Pinlay
– the inlay has additional cavities or pin inclusions for better fixation.

The type of inlay based on its position in the tooth is selected by the dentist after an initial consultation.

Contraindications

This type of microprosthesis cannot be installed in the following cases:

bruxism (grinding teeth in sleep);
steep slopes of hillocks;
rapidly progressing caries;
deep cavity extending into dentin;
inability to ensure complete dryness of the field.

A relative contraindication is poor oral hygiene. In what cases is it not advisable to use:

A cavity less than 1.5 mm deep (you can get by with a filling);
The damage has affected the cervical area of the tooth (the inlay will no longer help);
The tooth is more than 60% destroyed (a crown is required);
Milk tooth. It makes no sense to restore it using an inlay, since the life of the tooth is less than the durability of the microprosthesis. In addition, a vlkadka costs much more than a filling. Spending so much money to restore a tooth that will soon fall out is not advisable.

Advantages of inlays over fillings

Our doctors have long received confirmation that restoring teeth with inlays is more effective and reliable than traditional light-curing fillings.
Our doctors have long received confirmation that restoring teeth with inlays is more effective and reliable than traditional light-curing fillings. Even the least durable composite microprosthesis has much fewer disadvantages than a filling. If we talk about ceramics, then this material allows you to create almost ideal designs . In addition to the fact that inlays are much stronger than fillings, they have other advantages over fillings:

No need to sit in a chair for a long time with your mouth open.
The ability to completely restore the chewing function of the tooth (which not only kneads, but also thoroughly grinds food).
Higher design precision: the size between the ceramic or metal inlay and the dental tissue is measured in microns. With a filling, this indicator is significantly lower, so there is always a risk of secondary caries occurring underneath it.
Stability of high aesthetic properties . Composite fillings darken and lose their shine after 3-4 years . In our professorial clinic, we install ceramic inlays that closely match the color and structure of the tooth. We completely restore the chewing surface of your damaged tooth, returning or even improving its previous appearance. At the same time, our prices are quite affordable.

In the 22nd Century Professorial Dentistry, consultations with the chief physician are completely free . If necessary, you will get an explanation from your doctor about the specifics of installing restoration inlays specifically in your case.

We will treat your teeth while preserving as much of their healthy tissue as possible. The experience and qualifications of our doctors allow us to accurately select the optimal methods of treatment and dental prosthetics, even in very complex cases. Come to us and you will see for yourself!

Indications

The main use case is the treatment of caries. A ceramic inlay for a tooth is needed if its crown is destroyed by 25–60%. If the cavity occupies less than a quarter of the surface, then you can get by with a filling, but if more than 60%, then a crown is needed. Other indications for installation:

Destruction of non-carious origin;
The need to install a bridge prosthesis (microprostheses are placed on abutment teeth to increase their strength);
Increased abrasion of enamel.