CLASS III CAVITY cont.

Restoration of
primary incisors and
canines

Restoration due to :
o Caries
o Trauma
o Developmental defects
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CLASS III CAVITY
• Carious lesions on the proximal surfaces of anterior
primary teeth .
• If the carious lesion has not involve or weaken the
incisal angle, a small conventional class III cavity .
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CLASS III CAVITY cont.
•Mandibular primary incisors with small
proximal carious lesions may not require
conventional restorations.
• Enameloplasty of the affected proximal
surface (usually described as "disking") to open
the proximal contacts and to remove most, if
not all, of the cavitations, followed by topical
treatments with fluoride varnish.

Class III adhesive restoration
Conservative restoration for small
interproximal lesions must be kept very small
due to large size of the pulps.
Retention is achieved by using:
a. Retentive locks.
b. Bevel of cavo surface margin.
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Schematic drawing of carious lesions on the mesial surfaces of maxillary
primary central incisors that do not undermine the mesial angles of the
teeth. The dotted line indicates the proposed labial outline of the class III
cavitypreparation.
B, Proximal view illustrates that the class III preparation is limited to the
cervical two thirds of the primary incisor.
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MODIFIED CLASS III CAVITY
PREPARATION
The modified class III preparation uses a
dovetail on the lingual or occasionally on the
labial surfaces of the tooth.
The preparation allows for additional retention
and access necessary to insert the restorative
material properly.
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Lingual and labial views of a modified class III preparation for a maxillary
primary canine. The dovetail improves retention form of the preparation
and allows access for placing the restorative material to ensure
adequate contact with the adjacent tooth.
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Lingual and labial views of a modified class III
preparation for a mandibular primary canine.
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Steps in prep. Of a class III
Anesthesia and rubber dam application.
Place wooden wedge to minimize gingival
hemorrhage.
Access using No 330 bur or No 2 round bur.
Axial wall 0.5 mm in dentin.
Round bur on low speed to remove deep
decay.
Just break contact and keep incisal one third.
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Steps in prep. Of a class III Cont.
Dove tail or lock on the labial surface.
Place a short bevel 0.5 mm at the cavosurface
margin using fine taper diamond or flame-
shaped composite finishing burs.
Clean and dry the preparation.
Place a plastic or sectional metal matrix.
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Class V restoration for incisors and
canines
It may be adhesive ( most frequently) or
amalgam.
Most frequently on facial surface of canines.
Using bur No 330 until reaching denin.
Pulpal wall parallel to outer enamel surface.
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Lateral walls slightly flared.
Mechanical retention achieved by creating
smally undercuts at:
i. Gingivoaxial line angel.
ii. Incisoaxial line angle.
Short bevel for resin-based composite.

Adhesive
materials in
primary molars

Advantages of adhesive restorations in
1. Improved esthetic.
2. Low thermal conductivity.
3. Elimination of mercury.
4. More conservative .
primary molars:
5. Bonding of restorative material tooth
structure.
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Disadvantages of adhesive restoration
1. Increased operating time.
2. Technique sensitive.
3. Potential marginal leakage and postoperative
sensitivity.
4. Tendency to open or loss contact.
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General principles for resin based
composite restoration
• Composite resin restoration very negatively
affected by moisture.
• Preparation very conservative.
• No need for mechanical retention
(micromechanical retention) .
• Common sense and knowledge of dental
materials.
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Rubber dam placement prior to restoration of aproximal lesions with composite resin.

Class I and II prep. For adhesive
restorative material.
• The steps very similar to amalgam except:
1. Absolute moisture control.
2. Narrow ismuth (1/4).
3. Prep. restricted to the region of caries (no occlusal
extension and no extension to self cleansing areas).
4. Short bevel is highly desirable.
5. Dentin bonding or glass ionomer lining placed before
matrix band and adhesive material.
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