dentures
Dentures (abbreviation ZE ) is the collective term for any form of replacement of missing natural teeth . The planning, manufacture and integration of dental prostheses falls under the dental prosthetics specialty . A removable denture is called a denture .
history
The earliest dentures were false teeth made of ivory , wood or the bones of animals or deceased people. These were tied to remaining healthy front teeth with gold wires. This only had an aesthetic effect and improved pronunciation without being able to restore the chewing function. Teeth loosened by periodontitis, for example, were fixed with a similar procedure . Such artificial teeth and devices, which the Phoenicians and Etruscans were already familiar with, often led to inflammation in the mouth area, as bacteria easily attach themselves to the wires and replacement teeth. The dentures of Roman antiquity, which can be traced back to Etruscan influences, consisted of calf's or human teeth. One of the earliest archaeological finds in Central Europe comes from the Slavic burial ground of Sanzkow (Demmin district) from the 12th century. The first porcelain bites appeared at the end of the 18th century. The French pharmacist Alexis Duchâteau made the first porcelain teeth together with the French dentist Nicolas Dubois de Chémant in 1774. Dubois de Chémant later received a monopoly on the production of porcelain bites and introduced the porcelain pin crown in 1802. In 1785, New York dentist John Greenwood also introduced porcelain-based dentures. On March 9, 1822, Charles M. Graham from New York was granted a US patent for his invention of an improvement in the construction of artificial teeth. It was not until the 19th century that the raw material rubber made it possible to manufacture functioning dentures. Today replaced teeth are mostly made of plastic or ceramic materials. Dental restorations made of rubber are no longer used due to the increasing brittleness and porous surface as well as the poor aesthetics of the gums. Well-known prosthodontists have developed special procedures in order to achieve the best possible result. These include Albert Gerber , Alfred Gysi , Alexander Gutowski and Arne Lauritzen .
Systematics and distinguishing features
Dentures are divided into different classes: Fixed dentures include crowns, partial crowns and bridges, and removable dentures are divided into full dentures and partial dentures, which in turn can be divided into several subgroups. Either the design or the extent of the partial prosthesis can be used as a criterion. Combined dentures consist of a permanently cemented part and a removable part.
Dentures should restore the chewing performance of the partially or edentulous jaw. Other aspects concern aesthetics and speaking performance, as the pronunciation of some letters often depends on the presence and the correct position of the teeth.
Fixed dentures
Fixed dentures are attached to existing teeth, which then also carry the chewing forces of the replacement. The rule of thumb here is that each tooth can absorb the chewing pressure of another tooth. For two teeth to be replaced, two abutment teeth should also be available. The usability of abutment teeth as bridge anchors depends on the value of the abutments .
Fixed dentures come closest to the natural situation and are therefore - unlike removable dentures - able to almost completely restore normal chewing and speaking functions.
Bridges and crowns only stay in the mouth for a limited time - an average of around 15 to 20 years. Since the gums can recede as part of periodontitis , the main reason for the insufficiency of a crown or bridge is that the then exposed tooth neck becomes accessible again as a predilection for caries . Loosening of the teeth due to overloading can also lead to the loss of fixed dentures (especially in the upper jaw). The previous damage to the abutment teeth before the crowning is also important.
bridges
Bridges consist of bridge piers (fixing elements) and bridge body (s) (bridge members). Bridges can be made of metal, ceramic or a combination of both materials (veneer-metal-ceramic, abbreviated VMK) and are attached to the appropriately prepared (ground) abutment teeth with a special cement .
Telescoping bridge
A telescopic bridge is understood to be a bridge whose bridge piers are telescopic crowns (double crowns). Their wearing comfort corresponds to that of fixed dentures, as this construction is carried by the abutment teeth and the oral mucosa has no supporting function.
Adhesive bridge
In dentistry, an adhesive bridge is a bridge that is attached to the neighboring teeth with an adhesive bond . Such a bridge is also known as the Maryland Bridge after its place of origin . The great advantage of this type of gap closure is that, in contrast to the conventional bridge, the abutment teeth do not have to be ground all around, but only very little tooth substance has to be ground off. The procedure was therefore particularly suitable when the neighboring teeth were free of caries and fillings. An adhesive bridge is attached using the adhesive technique. Through a combination of surface treatment of the metal (sandblasting, silicatising, earlier also etching) and the use of special metal primers, an adhesive bond to the metal is also achieved (Käyser et al., 1997). In contrast to conventional bridge technology, the process saves a lot of tooth substance. The procedure did not prevail in Germany, which is mainly due to the fact that it never became a cash benefit (and there is now a better solution for such cases). Bridges of this type are less resilient than conventional bridges and also less durable. The adhesive bridge had a narrow range of indications and has therefore remained a niche application. In the meantime, implantology has largely replaced the adhesive bridge.
Dental crowns and partial crowns
Individual tooth crowns are not replacements , but serve to preserve the teeth. In connection with the replacement of teeth, dental crowns become part of dentures. In Germany, however, no distinction is made when billing a crown, but each crown is subsumed under dental prosthesis , which leads to the patient's own financial contribution. A tooth crown completely covers the tooth in question (like a thimble). Partial crowns do not completely cover the tooth in question.
Implants
An implant is a tooth root replacement onto which a crown or denture is attached. The function of implants corresponds to that of natural teeth. They can be used as bridge abutments, but also as holding and supporting elements for combined dentures. An implant can be indicated if a single tooth is missing, the neighboring teeth are healthy and these should not be prepared for a bridge, i.e. should not be ground. The dental implant is then crowned with a single crown.
Veneer
A veneer is a thin, translucent ceramic shell for the teeth that is glued to the tooth surface with a special adhesive.
Removable dentures (dentures)
Full denture
In dentistry, a full denture is the replacement of all teeth in a jaw with removable dentures that consist of a plastic base and the artificial teeth attached to it. The full denture is held on the jaw by negative pressure, adhesion and cohesion forces. For this purpose, the edge of the prosthesis is designed with the help of a functional impression.
A special form is the immediate prosthesis (immediate prosthesis). If a row extraction is necessary, a prosthesis is prepared in advance of the extractions , which is inserted immediately after the extraction of the teeth. Such a prosthesis is corrected after a few weeks, e.g. B. by relining, because the jaw changes significantly as the extraction wounds heal. A side effect of an immediate supply is that such a prosthesis also serves as a bandage plate. If it is not possible to wear a full denture due to bone loss, a jaw augmentation is indicated.
Partial denture
Differentiation according to the execution
In dentistry, partial dentures represent a tooth replacement that can be produced in the case of a set of teeth with residual teeth. A partial prosthesis (lat .: pars part) can be produced in different designs. The simplest version, the clasp prosthesis, consists of a plastic base, the teeth to be replaced and curved holding and support elements. These are the so-called clamps as holding elements and, at best, additional support spikes as support elements that are intended to prevent the prosthesis from sinking. If necessary, the prosthesis can be reinforced with an integrated wire or bracket. A clasp prosthesis is an interim prosthesis (transitional prosthesis, e.g. to wait a few weeks for the wound to heal after a tooth extraction ) and not a permanent solution, because it can damage the remaining natural teeth as well as the gums and the underlying bones (mechanical atrophy ). After the healing phase, the manufactured prosthesis must either be adapted or a new prosthesis made.
In the case of a partial denture model cast , a metal framework together with the holding and support elements is first produced in one cast on a jaw model. This process ensures a high degree of accuracy of fit and stability. As a rule, a chromium-cobalt-molybdenum alloy is used - but in recent years it has also been increasingly pure titanium , as this is particularly tissue-compatible. Plastic and teeth are then built up on this basis. It is important that a model cast prosthesis is designed to be periodontal -free, which means that a distance of several millimeters should be maintained between the natural teeth and the prosthesis wherever possible in order to avoid "dirty corners". Overall, such a partial denture model cast is more durable than the simple partial prosthesis described above and, above all, due to the better accuracy of fit and support, it can also be used as a permanent denture. Even with this version, long-term success is only guaranteed through regular and intensive care of the teeth and dentures .
Classification according to the scope
Partial dentures can also be classified according to the position of the replaced teeth:
A switching prosthesis closes a tooth gap . This means that there are natural teeth in front of ( mesial ) and behind ( distal ) the missing teeth. (See figure: Simple prosthesis )
A cantilever prosthesis ends with a prosthesis saddle that is not limited to the rear (distal) by a natural tooth. (See figure: model cast prosthesis )
Both switching prostheses and free-end prostheses can have prosthetic saddles on one or both sides. A combination is therefore also possible if, for. B. in the left lower jaw a tooth gap is enclosed by teeth at the front and back, and in the right lower jaw the row of teeth ends from the first premolar .
Combined dentures
In this section, no distinction is made between crowns on natural teeth or on dental implants, as both perform very similar functions in terms of design.
As the name suggests, a combined tooth replacement consists of a fixed and a removable part. The fixed part can consist of crowns - possibly also as part of a bridge, telescopic and / or conical crowns , bars or attachments or (only rarely) joints. A partial prosthesis is held precisely by this fixed construction. With telescopic and conical crowns, the hold is achieved by friction , with bars also often by friction, sometimes also by a "rider" that grips the bar like a clamp. Attachments consist of a male part on the fixed part and a female part on the removable part. They are available in very different designs and sizes: with small friction pins, with cone-like T-shaped latches or as a push-button-like ball head. (See pictures!) Often the "clamping effect" can also be adjusted or readjusted (activated) with a small screw. It is not always necessary to provide all remaining teeth with telescopic crowns; instead, individual teeth can also be included with cast holding and support elements to optimize the hold and support of the prosthesis. This also prevents the remaining teeth that are not crowned from tipping. The rest of the framework construction does not differ from a model cast prosthesis .
Advantages of the combined denture:
- very good hold on the remaining teeth and / or the implants
- very good support on the remaining teeth
- Compared to “normal” partial dentures, the teeth that are used for attachment are better protected against caries
- By blocking the remaining teeth, overloading of individual teeth can be avoided.
- To a certain extent, expansion or repair is possible.
The indication for a unilateral partial prosthesis without hold and support on the opposite side of the jaw should be made very cautiously, because tilting of the prosthesis - usually in the vestibular direction - often cannot be ruled out. In addition, a unilateral partial prosthesis should be designed in such a way that it can never come loose unintentionally, as it could otherwise be swallowed or get into the airways.
An example of a unilateral lower partial denture (special case)
Teeth 37, 36 and 35 will be replaced. Teeth 33 and 34 will be restored with VMK crowns. An activatable attachment attached to the crowns serves as a connecting element.
An example of a partial denture worn and held by implants
Total dentition reconstruction on dental implants, from vestibular
Total dentition reconstruction on dental implants, from the oral position - the entire construction can be removed for care and maintenance purposes
A special form of combined dentures is the cover or cover denture prosthesis, also known as a hybrid prosthesis . She is z. B. with telescopic crowns, bars on root post caps or spherical heads attached to the mostly only small remaining teeth. In addition to the limited load- bearing capacity of the rest of the teeth, the resilience of the denture bed also comes into play. When integrated, a cover denture prosthesis looks similar to a full prosthesis and is roughly the same size, but thanks to the "substructure" it is much more comfortable to wear and protects the prosthesis bed.
Bar prosthesis
A bar prosthesis is a partial prosthesis that is attached to a bar. The bar has a holding and supporting function and a round or rectangular cross-section. The bar blocks two or more teeth or implants.
Prosthetic material
Plastic is the material of choice as the prosthesis material for all types of prostheses . The denture teeth are usually made of largely abrasion-resistant plastic. Ceramic teeth were used earlier in particular because of their better aesthetics at the time, but are more prone to breakage and more difficult to grind, and they can only be polished to a limited extent after grinding. They can also generate an annoying rattling noise when you clench.
Polyetheretherketone (PEEK)
Polyetheretherketone (PEEK), a high-performance plastic , was developed by Imperial Chemical Industries (ICI) in England. The Victrex company took over the marketing until the material found its way into dentistry for the manufacture of dentures via Juvora in 2012 . In the solid state, PEEK can be machined with a CNC milling machine. Long-term studies are still pending.
In addition to CNC milling, there has been a PEEK filament that can be used for the manufacture of class IIa medical products since January 2016 . This can be processed with the material-efficient 3D printing process Fused Filament Fabrication .
Denture cleaning
For cleaning a prosthesis, the trade has special prosthesis brushes. Liquid soap, dishwashing detergent, but also curd soap can serve as cleaning agents . Toothpastes containing abrasives should not be used, as they roughen the denture plastic, thereby promoting the accumulation of tartar and plaque.
New processes in the manufacture of dentures
Dentures have also been manufactured using the CAD / CAM process for many years . This guarantees a high, constant quality and accuracy of fit at an acceptable cost.
Dental prostheses made of titanium alloys have been manufactured using the casting process for a relatively long time . Computer-aided production now makes it possible to produce crowns of very good quality at relatively low prices.
A relatively new material for fixed dentures is zirconium dioxide ( short name: zirconium oxide). The zirconium dioxide serves as a framework for all-ceramic crowns and all-ceramic bridges. A softer, temporomandibular joint-friendly ceramic material in the appropriate tooth color is fired onto this. In this way, natural teeth can be imitated much better than was possible with crowns and bridges with a metal framework. The costs are slightly higher than for veneering metal-ceramic work. However, because gold alloys have become increasingly expensive in recent years, the decision is now often in favor of ceramic restorations made from zirconium dioxide.
Advantages of all-ceramic crowns compared to precious metal restorations:
- the white base color
- lower raw material price compared to metals
- very good light transmission ( translucency )
- the biocompatibility .
Disadvantage:
- Elaborate cementation using the dentin adhesive technique
- lower stability than restorations with (precious) metal frameworks
The following are contraindications for all-ceramic dentures: Bruxism and allergic reactions to the materials used for dentine-adhesive cementation. If patients who suffer from bruxism are still provided with all-ceramic dentures, an occlusal splint is strongly recommended , especially at night .
Insufficient luting of all-ceramic crowns - with conventional cement , for example - carries the risk of leaks over time as the cement washes out and, as a result, caries develops, which can irreversibly damage the tooth - often unnoticed because the defect of the crown is covered. In the case of insufficient cementation, however, the risk of fracture in all-ceramic restorations also increases significantly.
Research at the Otto Schott Institute for Glass Chemistry in Jena is aimed at producing novel glass ceramics based on magnesium, aluminum and silicon dioxide with a nanocrystalline structure, which are suitable for use in dentistry due to their high strength and optical properties.
costs
A treatment and cost plan (HKP) for dental prosthetic services in Germany presents a planned dental prosthesis and its expected costs in detail. It fulfills two different functions, on the one hand it presents the dental services in writing in a therapy plan and on the other hand a cost estimate. It is used to make costs transparent for the payer and to clarify the extent to which costs are to be borne by the patient, by health insurance companies , by private health insurers , by the allowance or by the social welfare office . Treatment and cost plans must be drawn up for statutory and privately insured patients according to different provisions.
According to a forsa survey commissioned by a direct insurer, the average co-payment for dentures in Germany in 2012 was 1286 euros.
swell
- Christoph Benz : Dental project - typical problems in old people's homes - solution approaches for practice. In: ProAlter. 3/2006: 63-66
- Wolfgang B. Freesmeyer: Clinical Prosthetics, Vol. 1: Fixed and implant-supported dentures . Heidelberg: Karl F. Haug Fachbuchverlag, 1995, ISBN 3-8304-0125-6
- Wolfgang B. Freesmeyer: Clinical Prosthetics, Vol. 2: Removable dentures and tissue replacement (epithetics) . Heidelberg: Karl F. Haug Fachbuchverlag, 1999, ISBN 3-8304-0126-4
- Holste, T., A. Renk: Adhesive bridges in dentistry. Hanser, Munich - Vienna 1985
- Käyser, Arnold F .: Crown and bridge prosthetics: treatment planning, indication, execution, long-term performance. German Übers. P. Bottenberg, Cologne: Dt. Doctors Publ. 1997 ISBN 3-7691-4063-X
Web links
Individual evidence
- ↑ John Woodforde: The Strange History of the False Teeth, with a foreword and an appendix by Annemarie Leibbrand-Wettley. Munich 1968.
- ↑ Jutta Kollesch , Diethard Nickel : Ancient healing art. Selected texts from the medical writings of the Greeks and Romans. Philipp Reclam jun., Leipzig 1979 (= Reclams Universal Library. Volume 771); 6th edition ibid 1989, ISBN 3-379-00411-1 , p. 35.
- ↑ Gerd C. Koenig: Shaman and blacksmith, medicus and monk - an overview of the archeology of Merovingian medicine in southern Europe. In: Helvetia Archaeologica. 51/52 Zurich 1982. pp. 135-136.
- ↑ See also Heinrich-Alfred Dilsen: Porcelain and its use in dentistry. A historical study. Medical dissertation Cologne 1965.
- ↑ The Henry J. McKellops Collection in Dental Medicine .
- ^ Alfred Renk: Material science, dental. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , pp. 1472 f .; here: p. 1472.
- ↑ The Rotarian Magazine, Jun 1985, Issue 146, No. 6, p . 24 . ISSN 0035-838X , accessed on March 8, 2010.
- ↑ Peter Force: The National Calendar and Annals of the United States for 1823 , Volume 4, page 168.Washington 1823 , accessed on March 8, 2010.
- ↑ The history of the rubber prosthesis .
- ↑ Tooth misalignments .
- ↑ Leempoel PJB et al .: An evaluation of crowns and bridges in a general dental practice. (2008) Journal of Oral Rehabilitation.
- ^ B. Siewert, M. Parra, A new class of materials in dentistry, PEEK as a framework material for 12-unit implant-supported bridges . Z Zahnärztl Implantol 2013; 29: 148−159. Retrieved July 13, 2015.
- ↑ Press release PEEK MedTec Filament from Indmatec ( Memento from January 28, 2016 in the Internet Archive ). Accessed on January 28, 2016
- ↑ Aesthetic Dentistry Josef Schmidseder Volume 15 of the color atlases of dentistry 1998 published by Thieme Verlag Stuttgart. New York p. 195 ff, p. 120 and p. 234.
- ↑ M. Dittmer, C. Rüssel .: Colorless and high strength MgO / Al2O3 / SiO2 glass-ceramic dental material using zirconia as nucleating agent, Journal of Biomedical Materials Research Part B: Applied Biomaterials, 2011 Nov 21, doi: 10.1002 / jbm .b.31972
- ↑ Look at my teeth, kid . In: Handelsblatt . No. 121 , June 27, 2013, ISSN 0017-7296 , p. 28 .
