Inlay (dentistry)
An inlay ( English for insert filling ) is in a dental prepared laboratory tooth filling , which in the tooth , usually is used to caries effects to treat and to reconstruct the tooth defect characterized incurred. An inlay is a precisely fitting workpiece that is glued into the tooth, in contrast to plastic filling material, which is introduced into the tooth in a soft consistency using molding aids and then hardens. An inlay can be made of various materials, such as gold , ceramic , galvanic ceramic (combination of gold and ceramic), plastic and more recentlyTitanium .
Gold inlay
Dental care by means of a gold inlay places high demands on the dentist, as a shape in the tooth has to be created freehand using diamond grinders, which does not have any undercuts and at the same time ensures adequate retention, and on the dental technician who does the manufacturing process must adhere exactly. Two-surface and three-surface inlays can also be used as bridge anchors . As a result, the tooth substance of the abutment teeth is significantly spared compared to a full crown. The perfection of gold inlays is only surpassed by gold hammer fillings (gold leaf fillings ).
Dental gold alloy
Pure gold is too soft to be able to make permanent gold inlays from it. To improve the properties, an alloy is used that guarantees both durability and the necessary processing properties . Gold (Au) is added to palladium (Pd), platinum (Pt), silver (Ag), zinc (Zn) and, in small amounts, tin (Sn), iridium (Ir), rhenium (Re) and indium (In). Depending on the application, gold alloys with different degrees of hardness can be processed. Soft to medium-hard gold alloys are used for gold inlays. Copper as an alloy component has not been used since the 1970s, as the copper components oxidize and can thus turn dark. The alloy components also influence the gold color, whether it looks more yellow or reddish.
Alloy components of soft, copper-free dental gold alloys
- Au 78-96%
- Pd 0-4%
- Pt 0-10%
- Ag 0-18%
- Ir, Sn, Zn <1%
Alloy components of medium-hard, copper-free dental gold alloys
- Au 78-92%
- Pd 0-3%
- Pt 3–14%
- Ag 1-10%
- Zn 0-3%
- Ir, Sn, Re, In <1%
Fine gold is 24 carats . Dental gold alloys, on the other hand, are 20 to 22-carat alloys. The cost of one gram of a dental gold alloy is nevertheless higher than that of a gram of fine gold, because on the one hand the additional costs of alloy development and production are included and on the other hand dental gold is stamped, hallmarked and sold in 1 gram plates .
Dental preparation
First, the caries is completely removed from the cavity - if necessary under local anesthesia (local anesthesia) . The tooth is then prepared (ground) in order to receive an inlay. A "box" should be created, which is why this form of tooth preparation is called box preparation . The box consists of slightly conically prepared tooth walls (cone angle approx. 6 °), which are intended to create a retention shape. The problem area in production is the so-called preparation margin, the area that separates the prepared part from the unprepared. With gold inlays, special preparations, u. a. a feathered edge, or the carving of sharp edges and angles (chugging technique, see illustration), as well as the resulting possibility of finishing, a precise edge fit is possible, which ensures the tightness of the inlay. An impression of the tooth is then taken, which is used to make the model.
Dental production
The inlay is first modeled from wax on this model. The wax inlay is then embedded in a casting mold and melted out. The liquid gold alloy is introduced into the cavity created in this way. The blank is then finished and polished. The production of an inlay places high demands on the dental technician, because the numerous individual work steps are all prone to errors. The trick is that all occurring "errors" cancel each other out at the end of the manufacturing process, thereby guaranteeing the accuracy of fit of the finished inlay. The following example should be mentioned as representative of the manufacturing problems: The setting process of the plaster of paris for embedding the wax inlay must lead to a larger cavity than the size of the final inlay, since the gold alloy shrinks after the casting process when it cools. Otherwise it would end up being too small.
Dental insertion
Gold inlays are attached to the tooth with luting cements or resins. The dentist checks and corrects the correct clenching of the teeth ( occlusion ), checks the contact points with the neighboring teeth so that no food can be bitten between the teeth and finishes the edges of the tooth enamel in order to achieve the greatest possible tightness.
rating
Among all the materials currently available, the classic inlay material gold, which is processed in the form of a gold alloy , has so far been unmatched in terms of its durability and oral resistance. However, if the inlay preparation expands too much, a tooth cusp can break off, as conventionally cemented gold inlays, unlike cemented ceramic inlays, do not stabilize the natural tooth substance (internal splinting).
The durability of a precisely manufactured gold inlay is basically unlimited, provided that there is no caries elsewhere on the tooth or a piece of the tooth breaks off.
Ceramic inlay
Ceramic inlays consist of break-proof ceramic that can be manufactured in different ways. The advantage over a gold inlay is in particular the color, as the ceramic inlay can be adapted to the tooth color of the tooth. Furthermore, the dentine- adhesive bond between dentine and ceramic and the mechanical-retentive bond between tooth enamel and ceramic create a stabilization of weakened (too thin) tooth walls (cavity walls).
Dental procedure
The removal of carious substance and the preparation of the tooth cavity do not initially differ from the preparation for a gold inlay. However, there are a few special features to consider. Thinly tapering edges, as desired in the form of a so-called spring edge for gold inlays, should be avoided. Corners and edges are to be avoided, i. H. the preparation shape differs from the gold inlay in that it is rounded on the bottom of the cavity. The thickness of the ceramic inlay, like that of the remaining hard tooth substance, should be at least 2 mm. The preparation angle should be somewhat more conical than with the gold inlay (6 ° to 10 °). All of the measures mentioned are intended to minimize the risk of breakage. The tooth color is determined using a color scale. Mixed colors are only possible for hand-made inlays.
Dental procedure
A distinction must be made between different processes depending on the manufacturing process:
Fired ceramic inlay
There are different types of ceramics available for all-ceramic restorations:
- Silicate glass ceramic
- Alumina ceramic
- Zirconium oxide ceramic
Ceramic inlays are produced either by firing in layers in a ceramic furnace or by pressing a heated glass ceramic blank into a hollow mold.
Cerec procedure
CEREC (Chairside Economical Restoration of Esthetic Ceramics or CEramic REConstruction) is a CAD / CAM method for reconstructing dental occlusal surfaces. Using an intraoral camera, an optical impression instead of a conventional impression with impression material of the tooth to be restored is scanned and a three-dimensional model is calculated. This can be displayed and edited on the monitor. The inlay is then milled from a ceramic block by a robot. Alternatively, the optical impression can also be taken from the plaster model by a dental technician and made by the latter, because Cerec systems are only available in a few dental practices, as their acquisition and maintenance are cost-intensive.
A detailed color design, as it is done by a dental technician during production, is not given when milling from a given ceramic block. It is chosen from a range of ceramic shades. The accuracy of fit of a Cerec inlay is - also because of the still imprecise digital impression - less than that of a hand-made inlay. One relies on the fixing plastic here. A friction of the workpiece to hold and an exact edge fit is not aimed at (cannot be achieved due to manufacturing reasons), since edge gaps are filled by the plastic.
Dental insertion
Ceramic inlays are usually glued into the tooth with composites . For this, the inner surface of the ceramic inlay is silanized , the tooth enamel is slightly etched with phosphoric acid and the dentine is provided with a dentine adhesive. The light-curing composites are irradiated with halogen light. The further adjustment corresponds to the procedure for inserting a gold inlay.
rating
With greater effort and costs of the inlay compared to a plastic filling with composite, one often expects a longer service life. However, this cannot be shown in all long-term studies in the case of ceramic inlays.
Ceramic is generally well tolerated. The plastic-based adhesive used to attach the ceramic inlays poses a very low risk of allergy for the patient. If the color of the ceramic inlay has been perfectly matched, it is difficult to remove it again if this should become necessary. The transition between tooth substance and ceramic inlay is then difficult to see. A slight color deviation (hardly noticeable by the layperson) is therefore desirable. The greater hardness of the ceramic inlay can damage the opposing teeth. The radioactivity of ceramic inlays mentioned in some places based on the element zirconium as a component is negligibly low (approx. 0.01 mSievert based on 1 gram of inlay versus 2 - 3 mSievert from natural radioactive background radiation ) per year.
Galvanic inlay
The electroplated inlay is produced by applying a layer of pure gold to the model of the tooth to be restored using an electroplating process , which is then veneered with ceramic. The higher manufacturing costs result in higher costs. The thin but visible gold rim is perceived as annoying by patients.
Plastic inlay
Plastic inlays are made of composite and are similar in function and aesthetics to ceramic inlays. The material is somewhat softer, which is why a shorter service life of the inlay is to be expected due to higher abrasion . Plastic inlays can be adapted to the natural tooth color. They are pressed under high pressure in the laboratory. The fixation is carried out in a similar way to ceramic inlays with dentin / enamel adhesive materials.
rating
Similar to ceramic inlays, the durability of composite inlays compared to plastic composite fillings is rated in some long-term studies as not more durable or as only minimally more durable, but this was not seen as justifying the higher price and effort.
Titanium inlay
Titanium inlays are well tolerated in terms of their material, but have a silver-gray color. The processing of titanium requires special equipment in the dental laboratory . The technology is not yet mature. Titanium inlays are veneered (coated) with ceramic for a better look.
costs
Inlays are not part of the contract dental care to which a statutory health insurance patient would be entitled. However, he is entitled to the health insurance benefits if he opts for a more complex supply. The additional cost agreement for restorative therapy is regulated in Section 28 (2) SGB V. There it says:
“If insured persons choose additional care for dental fillings, they have to bear the additional costs themselves. In these cases, the health insurance companies must invoice the comparable, cheapest plastic filling as a contribution in kind. In the cases of sentence 2, a written agreement must be made between the dentist and the insured person before treatment begins. The additional cost regulation does not apply to cases in which intact plastic fillings are replaced. "
Billing for inlays is based on the fee schedule for dentists (GOZ). In the case of statutory health insurance patients, the cost of a statutory health insurance service will be deducted from the invoice by the dentist and settled with the health insurance company via the statutory health insurance association . If the insured person has chosen to reimburse the costs , he can have the costs of the contractual service reimbursed by his health insurance company. Additional dental insurance can reimburse inlay costs depending on the tariff.
Number of areas of inlays
Inlays, like other dental fillings, are differentiated according to their size. Teeth in the posterior region ( premolars , molars ) have five surfaces:
- outside (vestibular or buccal ),
- inside ( oral or lingual in the lower jaw, palatally in the upper jaw),
- Chewing surface ( occlusal ) and
- front and back ( approximal , or mesial and distal ).
Tooth neck fillings and inlays are made in the edge area of the tooth towards the gums. These are called cervical .
The areas are abbreviated with the first letters of the Latin names. For example, a mod inlay is an inlay that encompasses the tooth surfaces mesially, occlusally and distally.
Depending on whether one, two or more surfaces of the tooth have to be provided with an inlay, a distinction is made between single, double and multi-surface inlays.
Calculation according to GOZ
In Germany, the calculation is based on the GOZ.
| GOZ no. | Insert filling | 1-way | 2.3 times | 3.5 times |
|---|---|---|---|---|
| 2150 | single surface | € 64.17 | € 147.60 | € 224.60 |
| 2160 | two-sided | € 76.26 | € 175.41 | € 266.91 |
| 2170 | multi-surface | € 96.12 | € 221.07 | € 336.42 |
The multiplier (1 to 3.5 times) is calculated according to the following criteria:
"Within the fee framework, the fees are to be determined at reasonable discretion, taking into account the difficulty and the time required for the individual lines as well as the circumstances during the execution. The difficulty of the individual performance can also be due to the difficulty of the illness; Dimensioning criteria that have already been taken into account in the specification of services have to be disregarded. The 2.3 times the fee rate represents the average performance in terms of difficulty and time required; exceeding this fee rate is only permissible if special features of the assessment criteria specified in sentence 1 justify this; Services with a below-average level of difficulty or expenditure of time are to be calculated with a lower fee rate. "
By means of a written fee agreement according to § 2 GOZ, a higher multiplier than 3.5 times can be agreed in Germany before the start of the treatment. In this case, two written agreements are to be made for patients with statutory health insurance: on the one hand, an agreement that care will be provided according to the additional cost regulation (see above) and, on the other hand, that the maximum rate will be exceeded.
total cost
The total costs of an inlay are made up of several factors:
- the dental fee for the inlay (see table)
- the dental fee for accompanying services (e.g. local anesthesia, removal of deep caries, special measures, etc.)
- the material costs (e.g. impression material, ceramic blank)
- the dental technology costs plus. VAT
- the cost of the gold alloy (according to the current price) plus. VAT
In the dental technology area and for dental expenses, the reduced VAT rate of 7% applies in Germany.
Demarcation
The inlay is usually used to restore cavities in the posterior region and replaces parts of the occlusal surface, but not the cusps of the tooth . If the cusps bearing the chewing force are also covered, one speaks of an onlay (dome filling). Defective, weakened tooth walls are replaced by additional coupling (only) of those cusps of the tooth that carry the chewing force. It's kind of a bigger inlay. The overlay covers all the cusps of the tooth and replaces the entire chewing surface. The partial crown also partially includes the tooth walls. The definitions are not always clear, as the size differences between the inlay, the onlay, the overlay and the partial crown are partially fluid.
Web links
Individual evidence
- ^ Rau, Ströbel, basic knowledge for dental technicians, p. 159.
- ↑ DGZMK, statement, ceramic restorations (PDF; 135 kB)
- ^ WH Mörmann: Ceramic inlay - the posterior filling of the future. Lecture on March 30, 1985, Karlsruhe, “25 Years Academy for Dental Training, Karlsruhe”. 4th International Quintessence Symposium 1985.
- ^ WH Mörmann et al.: Marginal adaptation of adhesive porcelain inlays in vitro. In: Switzerland Mschr Zahnmed. 1985; 95, pp. 1118-1129.
- ↑ S. Windisch, A. Bindl: Accuracy of fit of all-ceramic Cerec-CAD / CIM anterior crowns and anterior crown caps. In: Acta Med Dent Helv. 4 (1999), pp. 29-37
- ↑ DGZMK, Tooth-colored restorations (PDF; 135 kB)
- ^ RT Lange, P. Pfeiffer: Clinical evaluation of ceramic inlays compared to composite restorations. In: Opera Dent. 34 (3) (2009), pp. 263-272, doi : 10.2341 / 08-95 .
- ↑ naturaldentistry.us
- ^ Klaus M. Lehmann; Elmar Hellwig; Hans-Jürgen Wenz. Dental Propaedeutics: Introduction to Dentistry; with 32 tables . German medical publisher; 2012. ISBN 978-3-7691-3434-6 , pp. 183-.
- ^ U. Pallesen, V. Qvist: Composite resin fillings and inlays. An 11-year evaluation. In: Clin Oral Invest. 7 (2003), pp. 71-79, doi : 10.1007 / s00784-003-0201-z
- ↑ JWV Van Dijken: Direct resin composite inlays / onlays: an 11 year follow-up. In: J Dent. 28 (2000), pp. 299-306, PMID 10785294 .
- ↑ § 28 SGB V
- ↑ Schedule of Fees for Dentists
- ↑ Section 12, Paragraph 2, No. 6 of the Sales Tax Act
