When you are dealing with the occurrence of cavities, it does not mean necessarily that you need a filling. Consult with your dentist, he may propose as an alternative to the usual filling a much better solution: inlay/encrustation.
Inlays are restorations (fillings) cast in the dental laboratory. Also known as indirect fillings, is a traditional method of restoring teeth, but due to the emerge of a wide variety of filling materials is frequently applied in dental offices, most often opting for glass ionomers and photopolymerizable composites because of the lower price and the less time needed to finish the work.
When the occlusal surface of the tooth has been damaged and is not suitable for normal filling, inlays provides the ability to restore severe substance losses suffered in the tooth.
What are actually inlays?
Dental inlays are the inlays, onlays and pinlays.
Inlay is a part of reconstruction that can recover 1-2 walls of a tooth, one side interdental and one is occlusal, made in the laboratory from materials that provide the same resistance to dental tissue and the same thermal expansion, optionally – the same color and appearance – as the tooth on which it is applied.
A dental inlay is larger than a regular filling but smaller than a dental crown. Cement is applied into the clean cavity. It is similar to a filling, but is positioned between the tooth cusps.
Onlay recover, unlike the inlay, a vestibular or orally side wall too covering the tooth as covers 2-3 up to 4 of the five walls of the tooth. High resistance makes it be the last resort before coronary the vital tooth.
An onlay is larger than an inlay and cover more dental cusps, therefore is known as partial crowns. In this way, is covering more of the tooth’s occlusal surface, but not entirely like dental crowns.
Pinlay is an inlay of devitalized tooth, has all the elements of the onlay’s outfit with the addition of one or more root.
Maintains and restores the tooth contact points of adjacent tooth better than traditional fillings, the interdental papilla is protected from the mastication pressure, restores tooth physiognomy and functionality.
These are necessary in cases such as:
1. proximal caries teeth (interdental) with more extensive destructions than 1mm;
2. proximal cavities difficult to access with composite fillings;
3. the lack of contact point or hardly to be created contacts;
4. cavities in mirror (the two neighboring teeth) vital teeth;
5. papilla affected by mastication forces that has to be rebuilt;
6. destruction of more than 60% of the crown of a tooth vital.
They can be used in most situations where can be made fillings when teeth have suffered injuries and damages caused by caries or fractures, and the damage is not large enough to require dental crown. Usually inlays are preferred when dental tissue loss is large and the dentist wants to protect the remaining tooth tissue.
Dental inlays can be made from ceramics, various alloys (CrNi, CrCo) or zirconium. (see image below)
Because they can be made from materials that mimic the natural color of teeth, inlays and onlays are preferred by patients to replace unsightly fillings in order to achieve a more natural look.
Zirconium is the preferred material in cosmetic dentistry and natural aesthetics due to its many qualities: it is durable, resistant (higher than ceramics), bio-compatible and is identical to the natural tooth structure.
The differences between the metal inlays and the zirconium inlays can be found in the aesthetic achievement.
Also zirconium inlays are more resistant than the ceramical ones.
Bear in mind that by patients with low caries activity (fewer cavities) and good oral hygiene, the inlays of zirconium may even have a longevity of 25-40 years.
The type of used materials influences the following factors: aesthetics, strength, durability and cost.
Types of inlay:
Depending on the production technique and application method inlays can be of two types:
– Direct – they are made in the dental practice and installed in a single dental visit
– Indirect – are made in dental laboratories and requires at least two visits to complete the restoration.
The chosen type depends on the integrity of tooth structure (how much remained from the tooth affected by caries) and the desired look after the procedure.
How many sessions are needed for an inlay?
For a direct inlay a single session is required (the dental practice must have its own dental lab to be processed on the spot inlays).
Obtaining an indirect inlay requires at least two treatment sessions. In the first session the dentist prepares the cavity and takes the shape model and send it to the lab. The technician pours the received shape model encrustation. The second session is dedicated to cementing encrustation or dental bonding.
Inlays can come off if the cement is eroded or combines with saliva when applied.
Inlays made of composite resin or porcelain can break if certain factors exert too much pressure on the tooth or if there is a contact with very hard particles.
The longevity of an inlay depends on the material from which it is made, on the resistance of the treated tooth, on the occlusion surface that is subject to restoration and on the patient’s cooperation to maintain a good oral hygiene and to make regular examinations.
Inlays are a better alternative than the glass ionomers restorations, composites or amalgams. Here are the main advantages of dental inlays:
** Fits to the upper edge (biocompatibility with gum tissue);
** Restoration of a perfect anatomical shape of the tooth by modeling in the laboratory;
** Restoration of perfect interdental contact points (maximum tightness against a composite filling);
** Unlike amalgam or metal fillings, the inlays are not coloring the tooth;
** The wear resistance is superior to any type of filling;
** Aesthetics in case of zirconium inlay (natural look);
** Does not require large time for adaptation, does not create discomfort: natural feeling installs from the beginning;
** The color does not change, what happens if the tooth restoration is made with composite materials;
** In some cases the encrustation provides protection for the remained dental tissues after removal of caries;
** Through the perfect restoration of contour, encrustation contributes to gum health maintenance;
** Helps eliminating tooth sensitivity;
** Determines a low or zero abrasion over opposite or adjacent tooth;
** Helps preventing tooth loss;
** The teeth can be more easily cleaned and maintained in terms of oral hygiene;
** Strengthens the tooth structure (approximately 75%);
** Minimizes risks of developing secondary caries (due to the optimal marginal closure );
** Unlike precious metal fillings, inlays and onlays are not shrinking or expanding at the influence of the temperature changes, action that weakens the tooth and cause a rupture or fracture;
** The longevity of such restorations reaches up to 40 years (due to resistance of materials and method of manufacture);
** Their superior strength and hardness is close to that of the tooth;
** Optimal restoration capacity: an onlay can recover 3, 4 fifths of a tooth crown.
** One of the greatest benefits in saving the damaged tooth is the avoidance of extensive dental restoration treatment (crowns, bridges, implants).
** Increased dental sacrifice compared with that required for application of a classic fillings or amalgam, glass ionomers and composites;
** On the unvital teeth the dental encrustation can act as a wedge, fracturing the tooth
** The high cost of this type of restoration is mainly due to the cost of inlay’s/onlay’s manufacturing in dental laboratory.
* The only alternative is the dental crown.
What to do:
Prior to the procedure, a local anesthetic is performed or the patient is given a sedative to help him / her to relax during the intervention.
Carious tissue is removed, then tooth surface is adequately prepared.
After preparing the tooth, it is applied a composite material to be molded in the cleaned place. Then encrustation is removed and hardened in a special oven. Now it is placed again in the prepared place and is cemented by the dentist and then sanded and polished to get a natural look.
Unlike those that are set and cemented in one day, the indirect inlays assume two sessions for finalisation. In the first session decay is removed and made a mold of the treated tooth and the adjacent ones – and the tooth receives a temporary filling. The mold comprises the treated tooth, the adjacent teeth and opposite tooth (to ensure correct occlusion).
In the second session, after removing the temporary filling and cleaning the tooth, it will placed encrustation processed in the laboratory after taken molding.
After sanding there are made the last adjustments for a complete and natural integration of the inlay to the dental whole and for avoiding the deficient or incorrect dental occlusion.
After the procedure’s completion, the patient can return to normal activities, experiencing only a slight tenderness in the treated area.
Four basic arguments for choosing dental inlays as a dental restoration method:
1 *. Dental inlays are much easier to clean and maintain than conventional dental crowns or fillings.
2 *. They provide effective preventive treatment against cavities.
3 *. They fit in perfect harmony in the mouth: they are fixed so well and naturally that will ensure the longevity and aesthetic dental restorations.
4 *. Ideal for repairing cavities appeared between teeth (decay that affected side walls of two adjacent teeth).