3. INITIAL TOOTH PREPARATION STAGE
STEP 1: Outline Form and Initial depth
STEP 2: Primary Resistance Form
STEP 3: Primary Retention Form
STEP 4: Convenience Form
4. STEP 1: OUTLINE FORM AND INITIAL DEPTH
To determine and develop the outline form while establishing the initial depth.
Extend the preparation to maintain sound tooth structure.
Initial depth should be 0.2 -0.8 mm from dentinoenamel junction.
Cuspal strength and marginal ridge strength should be preserved.
If the distance between two defects or tooth preparation is less than 0.5mm then
both the preparation of the tooth should be connected.
Restrict the depth of preparation from dentin.
ENAMELOPLASTY: It involves removal of shallow enamel developmental fissure
or pit to create smooth ,saucer shaped surface that is self cleansing or easily
cleaned.
5. ENAMELOPLASTY
It involves removal of shallow enamel developmental fissure or pit to create smooth ,saucer
shaped surface that is self cleansing or easily cleaned.
6. STEP 2: PRIMARY RESISTANCE FORM
It is that form/shape of tooth preparation that enables the restoration to
withstand the masticatory forces without fracture.
The pulpal floors should be relatively horizontal.
Box like shape preparation
Rounded internal line angles so that no dislodgement or fracture of
restoration.
Adequate thickness of restorative material.
7. STEP 3: PRIMARY RETENTION FORM
It is that form/shape of tooth preparation that prevents displacement or removal of
restorations by lifting forces.
The material should remain in the tooth preparation.
Because retention needs are related to restorative material used, the principles of
primary retention form vary ,depending on material.
For amalgam restorations, occlusal convergence and dove tail is given.
8. STEP 4: CONVENIENCE FORM
The tooth preparation should be convenient to operator to handle.
Preparation should have accessibility and visibility.
Width of the preparation should be increased.
9. FINAL TOOTH PREAPARATION STAGE
STEP 5: Removal of any remaining enamel pit or fissure,
infected dentin or old restorative material, if indicated.
STEP 6: Pulp protection, if indicated.(use of liners and
bases)
STEP 7: Secondary retention and resistance form.
STEP 8: Procedures for finishing the external walls of
tooth preparation
STEP 9: Final procedure- cleaning, inspecting and
desensitizing.