Filling therapy
The restorative treatment is part of the dental work and has the aim of carious lesions or other types of defects on individual teeth to fix. It is also called conservative or restorative therapy . Fillings (also: tooth fillings ) can be necessary both in the crown part and in the root part of a tooth.
Fill types
According to Greene Black , five cavity classes were distinguished, which was later expanded to include a sixth:
- I dimples and fissures in the occlusal surface (posterior teeth occlusal )
- II contact surfaces of the molars (posterior teeth approximal and possibly occlusal)
- III contact surfaces of cutting u. Canines, incisal edge not involved
- IV like III, but the incisal edge involved
- V tooth neck surface
- VI cusps of the molars (rarely affected alone)
In addition, the fillings are divided into one, two, three and multi-surface fillings according to the number of tooth surfaces affected.
Tooth fillings in the root part can be divided into external root fillings and internal root canal fillings . Root canal fillings can be placed from the coronal or from the apical angle. Apical root fillings are also called retrograde fillings .
Rules for cavity preparation
Black already defined criteria according to which a filling must be shaped:
Retention form
The filling must be shaped so that it is held in the tooth. In the case of amalgam fillings, this is done by preparing the cavity like an inverted light cone, i.e. the cavity becomes wider in the direction of the cavity floor.
In the case of “adhesively” attached fillings, the cavity does not need to be retained as these fillings adhere to the contact surface. Low-viscosity dentin bonding agent can penetrate into the surface structures and produce after chemical curing by microretention a micromechanical composite via tags ( engl. : Pin ) in the tubules between enamel, dentin and the composite resin (plastic filling). As a result, macromechanical retention, as with amalgam filling, can be dispensed with, which results in a greater loss of tooth substance.
Resistance form
The filling must be shaped so that it can withstand chewing pressure. However, the form of resistance relates not only to the filling, but also to the tooth itself. After preparation, the filling and the tooth should have sufficient "resistance" or stability under pressure from chewing.
Extension shape
The filling should be shaped in such a way that it encloses the areas where tooth decay is likely to occur ( predilection sites ). The rule established by Black is: "Extension for prevention" ( English : extension for the prevention [of caries]). Since the introduction of micro-invasive or adhesive filling therapy, this requirement has been viewed in a more differentiated manner.
Filling materials
A basic distinction must be made between plastic and rigid filling materials .
Plastic filling materials are those that are inserted into the tooth in a deformable state and harden there. The remaining fillings are molded outside of the mouth and then inserted into the tooth.
In the past, this distinction was made between direct and inlay fillings , but the CAD - CAM processes have led to forms of therapy that work without an impression, i.e. that should actually be added to the direct fillings, but are not plastic fillings.
Plastic filling materials
A classic example is the amalgam filling , which, as a Chinese amalgam recipe from the 7th century AD shows, has been used for centuries. The amalgam filling is indicated for fillings of cavity classes I and II.
Other plastic filling materials are composites (referred to in practice as plastic ), compomers , glass ionomer cement and other cements, as well as the gold hammer filling . Of these, only the composites are indicated for adhesive cementation in the chewed area. Compomers and glass ionomer cements can be used for definitive fillings in areas that are not subject to chewing. All other cements are now only used as temporary filling materials.
Plastics were available in the early 1940s at the latest, when the dentist Ernst Schnebel († 1942) invented a corresponding material that was suitable for crowns and bridges in addition to fillings.
Action
Once the caries has been removed, the dentine wound must be closed. In the case of shallow cavities, this can be done by painting (for example with Copal resin ); in the case of deeper cavities, it is done with cement underfilling (usually glass ionomer cement or zinc oxide-phosphate cement ). With adhesively attached fillings, the dentin wound is treated by bonding .
If the caries goes so deep that it penetrates into the immediate vicinity of the pulp , the formation of new dentin must be stimulated with a drug containing calcium hydroxide before the lining is placed. This covering of the pulp by the drug is called capping ; if the dentin layer above the pulp is still intact, it is referred to as indirect capping ; if it is open, it is referred to as direct capping . According to various studies, mineral trioxide aggregate (MTA) has proven to be superior to calcium hydroxide for direct capping .
Matrices , wedges and other aids are used to shape the filling .
Freshly mixed silver amalgam is then added in portions and condensed (“stuffed”). The latter can be done with hand instruments or by machine. The cavity is overfilled and the excess is then carved out again in the shape of a tooth.
The amalgam filling is completely hardened after twenty-four hours at the earliest and should be polished. The polishing not only leads to a compensation of the surface, but also reduces the surface by several powers of ten, which reduces any pollutant emissions to the same extent ( diffusion laws ).
In class I and II cavities, even when composites or compomers are supplied, the material is introduced in a slight excess in order to be able to remove the oxygen inhibition layer during finishing . Alternatively, the formation of the oxygen inhibition layer can be prevented by using glycerin gel before curing. In the case of the other filling classes, the formation of an oxygen inhibition layer can be prevented by curing against the die.
Durability and other aspects
A report on a literature search by DIMDI from 2008 comes to the conclusion that amalgams have a longer shelf life than composite fillings, although the study results are very inconsistent. The durability of composites has increased significantly since the early 1990s.
"In addition to the shelf life of amalgam, other aspects such as (individual) safety concerns, environmental protection, aesthetic demands or the long-term possibility of filling replacement must also be taken into account when choosing the appropriate dental filling material", as well as the additional payment or assumption of costs by health insurance.
Inlay fillings and partial crowns
Inlays
An inlay (also insert filling is called) one by one impression produced in the dental laboratory tooth filling, which fits exactly into the cavity. Examples are gold cast fillings (gold inlays) and ceramic inlays. Alternatively, an optical impression is taken and a ceramic inlay is milled from a blank in a ceramic milling device, computer-controlled .
Onlays
An onlay (also called dome filling ) is the replacement of the defective, weakened tooth walls by reaching over the onlay over the cusps of the tooth, which carry the chewing force.
The transitions from the inlay to the onlay to the overlay to the partial crown are fluid.
Clinical performance
Plastic fillers that are cured by polymerizing will shrink through this step. This can lead to tension and very small gaps at the edge areas of the filling. This problem is to be avoided by the more complex and expensive inlays. In the case of inlay restorations, a distinction is made between gold inlays, ceramic inlays and composite inlays. Compared to composite fillings, a German study over eight years found no significant differences in durability compared to ceramic inlays; in a Danish eleven-year study, an equivalent restoration compared with composite inlays. An eleven-year Swedish study assessed a lower but insignificant failure rate of composite inlays as not justifying the greater effort.
See also
- Evaluation standard of dental services, BEMA numbers 13a to 13g
- CEREC
- Dental alloys
- History of dentistry
Individual evidence
- ^ Alfred Renk: Tooth fillings. 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 , p. 1517.
- ^ Wolfgang Bengel: Amalgam material and clinic. In: Die Quintessenz , Volume 41, Issue 7, July 1990, p. 1130.
- ↑ When the ravages of time gnaw your teeth…. In: Kleine Wiener Kriegszeitung , January 13, 1945, p. 5 (online at ANNO ).
- ↑ Kathrin Schönenberger Göhring, Birgit Lehnert, Matthias Zehnder: Indication areas of MTA, an overview. Part 2: Clinical Application . In: Swiss monthly for dentistry . Vol. 114, No. 3 , 2004, p. 223 ff . ( sso.ch [PDF]).
- ↑ Elmar Hellwig, Joachim Klimek, Thomas Attin: Introduction to dental conservation. 6th, revised edition. Deutscher Ärzte-Verlag, Cologne 2013, ISBN 978-3-7691-3448-3 , pp. 277 ff.
- ↑ HTA report 76 (PDF) Shelf life of dental amalgam compared to composite plastics, Section 4.7, DIMDI , 2008
- ^ LF Schneider, LM Cavalcante, N. Silikas: Shrinkage Stresses Generated during Resin-Composite Applications: A Review. In: J Dent Biomech. 2010 (open access) doi: 10.4061 / 2010/131630
- ^ RT Lange, P. Pfeiffer; Oper Dent: Clinical evaluation of ceramic inlays compared to composite restorations. +34 (3), May-Jun 2009, pp. 263-272. doi: 10.2341 / 08-95
- ^ U. Pallesen, V. Qvist: Composite resin fillings and inlays. An 11-year evaluation. In: Clinical Oral Investigations . Volume 7, Number 2, June 2003, pp. 71-79, ISSN 1432-6981 . doi: 10.1007 / s00784-003-0201-z . PMID 12740693 .
- ↑ JW van Dijken: Direct resin composite inlays / onlays: an 11 year follow-up. In: Journal of Dentistry . Volume 28, Number 5, July 2000, pp. 299-306, ISSN 0300-5712 . PMID 10785294 .
