Class V cavity
Location:
Cervical area
Class V cavities include caries or defects of non-carious origin (erosions, abrasions, and wedge
defects).
All hard dental tissues meet in the cervical area, a continuous flow of liquid from gingival sulcus
makes it difficult to keep a dry working field. Dental tissue layers are very thin here and there is a
considerable risk of opening the pulp chamber.
Fig. 1: A scheme of possible layout of dental tissues in the cervical area and localisation of the cavity
Materials:
Amalgam (in the side part of teeth)
Composite (for cavities primarily in the enamel, especially in the frontal part of teeth, excellent
hygiene, a dry working field is easily kept).
Glass ionomer cement (for cavities located mainly elsewhere than in enamel, difficulties to keep the
working field dry, average oral hygiene).
Combination of glass ionomer cement and composite (sandwich filling)
.Access to the defect – the defect is directly accessible.
Cavosurface margin
PREPARATION FOR AMALGAM
The cavity is extended by ca 0.5 mm below the gingiva, it reaches mesially and distally up to the wall
which is located between the vestibular (oral) surface and proximal surface. (axial wall). Occlusal
surface lies below maximal convexity.
We prepare undercuts.
The depth of the cavity is 0.75 mm gingivally and 1.2 mm occlusally.
The pulpal wall follows the convexity of the tooth.
We start the preparation with a diamond pear-shaped bur with standard grit (blue code). We
smoothen the walls with a fine bur of the same shape (red code).
Fig. 2: A cavity for amalgam
PREPARATION FOR COMPOSITE
The cavity is located supragingivally, it is limited to the carious lesion and has a box shape with
rounded walls. Pulp wall again follows the convexity of the tooth. We bevel the enamel in order to
remove the aprismatic enamel and achieve good retentive pattern. If the cavity exceeds the enamel,
then we do not bevel walls in that part of cavity.
We start the preparation with a diamond pear-shaped bur with standard grit (blue code). We bevel
the walls of the cavity in enamel by a fine diamond cylindrical pointed bur (red code), we only
smoothen the walls outside the enamel with the same type of bur.
Fig. 3: A cavity for composite localised in enamel, the enamel is bevelled
Fig. 4: A cavity for composite localised only partly in the enamel. The enamel is bevelled, and the
edge of the cavity outside of the enamel is only smoothen. A suitable material is composite or glass
ionomer cement in combination with composite (sandwich filling). The glass ionomer cement
replaces the lost dentin while composite the enamel.
We prepare the cavity for glass ionomer cement in the extent of the carious lesion, we smoothen the
walls.
Fig. 5: A cavity for glass ionomer cement located outside of the enamel. The walls are only
smoothened.
MAKING OF THE FILLING
Dry working field and a matrix
It is difficult to keep the working field dry in the cervical area. Sometimes it is difficult to apply
cofferdam even if the retraction clamp is used. It is recommended to place the retraction thread into
the gingival sulcus.
Transparent cervical matrices of various sizes can be used for composite. The same matrices may also
be used for glass ionomer cement, although there are special matrices for glass ionomer cement
made of soft metal with a special surface treatment.
For securing a dry working field, we can use Belvedere matrix it is placed around the tooth, into the
gingival sulcus and sealed with wedges. It is suitable for composite filling.
Amalgam
We condense the filling material in layers, and in the end we smoothen it with a burnisher so that the
transition between the filling and the tooth is smooth. We polish the filling during the next
appointment.
Composite
We make the filling according to the rules for working with composite (etching, rinsing, application of
primer and bond, polymerisation, depositing in layers, thorough polymerisation, shaping and
polishing).
Glass ionomer cement
We treat the cavity by a conditioner, rinse it, apply cement in excess, and after its solidification we
cover it with a protective varnish. We shape it as little as possible, we leave that preferably to the
next appointment.