A dental matrix is a band that adapts to the surface of the tooth to be restored, reproducing its anatomical contours, replacing the missing wall or walls while the restoration is being performed, thus transforming a composite cavity into a simple cavity for easy restoration.
Dental matrices basic features
To achieve this function, it is necessary that the dental matrices comply with certain requirements such as:
- Restrain the restorative material.
- Dental matrices must be able to withstand the force required to insert the filling without the material overflowing.
- Protecting the restorative material.
- Contributing to the surface finish.
- Allow a suitable point of contact.
In order to perform the functions described above, dental matrices need to have a number of properties besides the requirements we mentioned above. The role of the dentist is to choose the most suitable dental matrix for each case having all this aspects in mind.
What to look for when choosing dental matrix?
- Rigidity : Adequate stiffness for insertion in proximal areas
- Compatibility between the restoration material and the matrix :The interaction between the restoration material and the matrix will invalidate the matrix for the correct exercise of its functions, by preventing an adequate restoration from being achieved. This incompatibility may be of a chemical nature, as in the case of celluloid matrices, which may inhibit the setting reaction of acrylic resins, or of a physical-chemical nature, as in the case of the latest generation of adhesives: Certain adhesive techniques may result in the adhesion of the restorative material to the matrix, which prevents its subsequent disinsertion without the removal of the filling material. It is necessary to package the internal side of the matrix to avoid this.
- Easy adaptability to the tooth: this feature is related to the flexibility of the dental matrix to wrap the tooth with just the amount of pressure needed.
- Ability to be contoured and flexibility for perfect adaptation to the margins of the restoration
- Prevention of gingival access
- Strenght to offer resistance to condensation pressure: Non-slip stability once in place
- Easy removal of the tooth and minimum thickness to avoid separation between adjacent teeth.
Types of matrices
There are many features about dental matrices in which we can base to clasify them, here is a few parameters that help us categorize them.
According to material:
Metallic: Silver, Bronze, Copper, Titanium, Steel,
Plastic: Acetate, Celluloid, Vinyl, Cellophane
According to their stabilization
Matrices that do not need a matrix holder: they have great stability and rigidity; the latter is a disadvantage for their conformation, especially at the gingival level.
According to their manufacture
Conformed: these have the disadvantage of not allowing a correct contact relationship to be re-established in ratio to their location and shape, this is due to the fact that they cannot be modified to carry elastic memory.
Laminates: these dental matrices are versatile and can be modified, obtaining contact ratio, shapes and contours closer to the individual reality of the case.
According to their tailoring:
Universals:these are made by industrial manufacturers, standarized, can be metallic or non-metallic. Some of these are: Tofflemire, Automatrices, Mylar Matrix, Omnimatrix, Optramatrix, Sectional Matrixes, Cervical Matrixes.
Individuals: these are made by the Dentist, according to the case being treated, so they are called individual. Some of these are: Individual Hollemback Matrix and Black Matrix.