DE19924116A1 - Plastic filled ceramic cap, for use as tooth crown, manufacture comprises a plastic secondary part, introduced into the interior of a primary part, placed over a tooth stump, before curing the plastic and fixing both parts in position - Google Patents

Abstract

A ceramic cap is produced with an open interior to form a primary part. A secondary material is then introduced into the interior of the primary part and both are then pressed onto the tooth stump where the secondary material is cured to form a secondary part. Both primary and secondary parts are removed from the stump and then securely reattached.

Description

Problem

The restoration of a large tooth defect with a crown, to restore the healthy chewing function, is due to the physiological situation of the chewing organ, as before a exhausting procedure for patient, dentist and dental technician.

High demands on precision, material properties and aesthetic feeling are prerequisites for the demands of To satisfy customers. This requires a variety of Steps that are time consuming and device intensive by Specialists are to be provided.

State of the art

Only parts that have a relevant reference to are mentioned Have invention.

Assembled sleeve crowns

Metallic flexible caps are on the tooth stump cemented on. They don't last long and can Perforations, gingivitis and secondary caries result. They are still used in some developing countries, and also tolerated on the milk teeth as a short-term solution.

Frasacco teeth

A ceramic facet is mechanically set on a full cast crown (Rech, drum).

Poor durability and poor aesthetics have the Change led by the full-coat ceramic (VMK) crown.

Metal crown veneered (general)

The course of tooth preparation by tangential, fillet or Step cut with subsequent precision impression and Bite registration at the dentist, as well as subsequent preparation a precisely fitting sleeve on the tooth stump through the laboratory on which the ceramic / plastic veneer can be applied as known to be assumed.

Systematic, creeping mistakes Multiple trials on the patient necessary (scaffolding, raw fire and individualized fittings).

As a rule, the patient's cooperation consists in tolerating the earth the procedure. The patient is usually in a stressed state Color selection of the crown included.  

Form, position and characteristic color inlays are mostly left to the dentist and dental technician, and if necessary in Corrected afterwards.

Overall, the effort in terms of staff, materials and equipment as well "Tolerance cooperation" of the patient is not insignificant.

Ceramic veneer

It is currently the most common type of use. The main advantage of ceramics is their permanent gloss and color stability, as well as compatibility. Your disadvantage in the unyielding hardness (brittle with less Tensile strength) and thus risk of breakage (chipping of the ceramic), especially where their thickness cannot withstand the chewing pressure can (scaffold bend) or where there is only one for cosmetic reasons thin ceramic veneering takes place (tooth necks etc.). The possibility of repairs in the mouth has so far been unsatisfactory.

Plastic facing

It is aesthetically equivalent to ceramics. It is easier and requires fewer devices than ceramics. Their disadvantage is the lower hardness and therefore less Abrasion resistance (Janda), which results in a decreasing gloss and noticeable blunting of the crown.

Daylight can also cause a gradual change in color cause.

Hydrolysis can cause swellings of moisture, which too leads to a decrease in bond strength.

The roughness of the Plastic led to a reduced polishability and Impairment of the surface zeta potential and thus Increase in plaque liability.

Tissue compatibility is also possible with the elimination of undisputed residual monomers.

The new tooth-colored adhesive plastics in the form of the The finest particle composites seem to be the ones that were in effect up to then To counter prejudice.

There will be abrasion resistance from hard amalgams or medium-hard gold-based alloys found (Körber). Hydrolysing phenomena do not seem to occur at all (Ludwig; Zabghellini).

Jacket Crowns (General)

They don't have a metallic core; they consist entirely of Plastic or all ceramic. This allows one achieve high-quality aesthetics (fluorescence, opacity, Depth effect, chameleon effect, ect.).  

All-plastic crowns (e.g. Ivoclar-Targis / Ceromer)

In principle, the disadvantages of plastics are the new ones Fine particle composite cleared. But since long-term experiences are missing, the all-ceramic crown is first replaced by dentists as before preferred.

In developing countries, where close cooperation with a high-quality dental laboratory is not always given, this is experienced System of relatively light manufacture with high aesthetic Result, brisk demand.

All-ceramic crown (e.g. Empress-Ivoclar)

Their gloss and color stability, as well as tissue compatibility, are second to none.

However, it requires precise tooth preparation (risk of Predetermined breaking provocation by preparation edges) and is of their required minimum layer thickness in their Indication area restricted (Lower jaw front teeth; large pulpy teeth, ect.). In addition, there is considerable technical and human resources Manufacturing effort added, which discourages many interested parties.

Cerec crown (Sirona)

It is identical to the all-ceramic crown. Your difference lies in the manufacture of crowns by a milling machine from one Ceramic block. Before that, an optical impression is made using video from the tooth stump manufactured and by puncturing the Preparation margin and programming the milling crown milled from the block.

System-related inaccuracies are made with Aluminia Optimizer (Vita) and Tetric-Ceram (Vivadent) balanced.

The crown usually only consists of a ceramic layer. The laboratory equipment required for production can be sent to the Treatment place are brought.

For overall production (tooth preparation - recording and Programming - milling - treatment - glazing - insertion) are likely to be more than the length of time of anesthesia to be needed.  

Bulk

The method and procedure to be described enables To make dentists' crowns as large as possible eliminates the disadvantages described, without the desired advantages give up, and also handling qualities exhibits that were previously not given.

There are two kinds of tooth-like plastic materials used.

The primary part of the material represents a hardened molded one Crown sleeve, comparable to the amount of enamel on the tooth. The secondary part, serves in its kneadable processing as individually shaped adaptation part to the tooth stump, comparable to the proportion of dentin in natural teeth.

By occlusal pressing of the primary part against the tooth stump, the secondary mass in the primary section flows up to Preparation margins. It forms the outer raw form, and final precise inner shape of the secondary part.

In this state, the secondary mass on the tooth stump cured and at the same time the bond with the primary part achieved.

As a result, the primary crown sleeve (primary part) serves as Negative form for the production of a load bearing on the tooth Crown (secondary part).

The superficial impression that it is just that Cementing a badly fitting crown is misleading.

The sleeve (primary part) is not used as a crown, but it deliberately becomes a recessed cavity to the tooth stump towards the secondary mass, which after curing, a supporting crown (secondary part) results.

The secondary mass has all the necessary physical Material properties of a full-fledged crown that are already has proven itself as such in practice.

The specified method also makes it highly precise Fit the crown (secondary part) on the tooth stump Direct print reached.

In addition, there is an even contact surface for the primary part and thereby reduces the risk of breakage created preparation edges.  

Manufacturing process

A made-up crown cap (primary part), which in its Shape, color and surface correspond to the typical tooth pattern, with regard to its contact points with the neighboring teeth (front, Posterior and opposite teeth) adapted by grinding.

It should be able to be placed on the tooth stump without contact, without to reach down to the preparation margin.

The end should be the contours of a natural enamel rim same, so that the load-bearing crown (secondary part) on the protected Gumline comes to rest while exposed to abrasion Melting part, the primary part rests.

Because the most intimate connection possible from the primary to the secondary part to be educated, the inner part of the crown cap pre-treated.

The application of the modelable secondary mass in the inner part of the Primary part (possibly also on the tooth stump) should, if possible bubble free.

Before that are the undercuts on the tooth stump to be excluded with certainty (possibly sealing).

After that is an isolation of the tooth stump from the secondary mass to remove the hardened secondary crown to ensure.

When applying the secondary mass to the tooth stump, ensure:

• - That this reaches the preparation limit and is good there seals,
• - That the occlusal position of the primary part did not sag or was postponed
• - That no excess of the secondary mass in the approximal space flows in order not to block a crown withdrawal (secondary part),
• - That the secondary mass is not the front edge of the primary part covered, as this ver with an untreated gloss layer is see and is not suitable for the association.

After light curing of the secondary mass, the excess Part removed and shaped.

Then the sanded outer areas of the primary and secondary part polished to a high gloss, and with the known Method cemented on the tooth stump. (e.g. etching gel, Syntac, Variolink / dual cement).  

Use of materials

All required materials are commercially available and have already proven themselves in practice.

The materials of the primary and secondary parts should be as possible be like and equal.

It is important to coordinate the network and the WAK values.

Tooth-colored substances are only to the current state of the art achievable with ceramic or plastic materials, the latter as a very fine particle composite (plastic ceramic) Find.

For the primary part (cap) the new fine particle composites are out of the question for the time being, since their durability in gloss and hardness is questionable in the long run. Ceramic is used here.

For the secondary part (crown) cuts ceramic for manufacture in the oral cavity, on the ground its method of manufacture.

The new composites are used here.

Should in future material development (INM, DE 197 19 948 A1) Let plastic seals develop on the surface show the same ceramic properties, so would the primary part conceivable from plastic.

It would also be desirable for the new composites to be one ceramic glaze firing (possibly with low-melting mass) to be able to apply.

From today's point of view, a combination of ceramic (primary part) with fine particle composite (secondary part) is still required:

• - The chemical bond is achieved by etching with Phosphoric acid, silanization with Monobond S / Rely X as Ceramic primer and subsequent application with Heliobond / Scotchbond as a compound initiator (Vivadent / 3M). 3M demands a high proportion of silicon / zirconium in the primary part.
• A tribochemical composite can also be generated, by radiating crystalline silica to the surface, which is equivalent to a "cold" silication and clearly has higher bond values (cojet system; aspen)
• - In addition, an attachment of grooves or undercut Places for the purely mechanical hold.

The multiple composite, given a wider and more uniform  Contact surface of the primary part, should be a secure bond guarantee.

The connection of the load-bearing plastic crown (secondary part) with the Tooth stump, can also be considered secured.

The advantages of the described method achieved in this way and methods of making dental crowns diverse.

The crown is made:

• - without large devices in one operation at the treatment chair
• - within a short time (adapting - milling - polishing)
• - Price significantly below previous costs (Elimination of impressions, temporaries, fittings, laboratory costs Etc.)
• - including patient selection, directly in the Oral cavity, with regard to crown, color, shape and position. Similar to the choice of glasses, the patient can his tooth stump, different crown models playful try out.

The above advantages are NOVUM in the dental Crown application.

In addition, the patient receives a multi-layer and Metal core-free HIGH AESTHETIC crown, its DURABILITY AT LEAST AS SAVED (full plastic crowns; chemical composite of Ceramics to "plastic ceramics") if not as improved, must be viewed (high-precision crown by direct impression; Multiple composite of different layers; wide and uniform Composite pad).

Characteristics of the invention Procedural feature

Achieving a high-precision crown by using a ready-made caps as a negative form, for the Direct impression of the tooth stump while using the Cap as the outer part of the final crown.

Claims (11)

1. A process for producing a dental crown for a tooth stump, characterized by the following process steps:

• Provision of a ceramic cap serving as the primary part and having an open interior area,
• Introduction of a deformable secondary mass into the interior of the primary part,
• Pressing the primary part with the secondary mass onto the tooth stump,
• Curing of the secondary mass to form a secondary part,
• Removing the primary part and the secondary part from the tooth stump,
• - Attach the primary part and the secondary part to the tooth stump.

2. The method according to claim 1, characterized in that before the introduction against the deformable secondary mass in the interior of the primary part fit the primary part such that the primary part is non-contact on the Tooth stump can be placed, with a between the primary part and the tooth stump continuous cavity is formed. 3. The method according to claim 1 or 2, characterized in that the Pri Market section before introducing the deformable secondary mass into the interior the primary part is adjusted so that it is not in its pressed position down to the preparation margin of the tooth stump. 4. The method according to any one of claims 1 to 3, characterized in that the primary part before introducing the deformable secondary mass into the interior Rich of the primary part is adjusted so that the peripheral edge of the open End of the primary part rests in the pressed position on the secondary part, see above that the primary part is not in contact with the tooth stump during any phase of the procedure is direct contact.   5. The method according to any one of claims 1 to 4, characterized in that before introducing the deformable secondary mass into the interior of the Pri areas or grooves in and / or on the inside of the Primary part - to increase the later mechanical hold between the primary part and secondary part - are trained. 6. The method according to any one of claims 1 to 5, characterized in that the tooth stump before pressing the primary part with the secondary mass on the Tooth stump is isolated from the secondary mass. 7. The method according to any one of claims 1 to 6, characterized in that before pressing the primary part with the secondary mass onto the tooth stump undercutting areas on the tooth stump are eliminated. 8. The method according to any one of claims 1 to 7, characterized in that during the curing of the secondary mass to form a secondary part at the same time a connection between the primary part and the secondary part is produced becomes. 9. The method according to any one of claims 1 to 8, characterized in that a full, load-bearing crown is formed by the secondary part. 10. The method according to any one of claims 1 to 9, characterized in that the attachment of the primary part and the secondary part on the tooth stump by a Cementing takes place. 11. The method according to any one of claims 1 to 10, characterized in that the secondary mass is a plastic material, preferably a very fine particle composite sit, is.