Aims of Tooth Preparation
- Remove defects and provide protection to pulp.
- Extend restoration conservatively.
- Increase resistance to fracture.
- Allow esthetic and functional placement of material.
Stages of Tooth Preparation
- Initial tooth preparation
- Final tooth preparation
Factors Affecting Tooth Preparation
- Diagnosis: pulpal and periodontal status, occlusal relationships, esthetics, relationship of restorative procedure to other treatment, risk potential.
- Knowledge of Dental Anatomy: knowledge of the external and internal structures of the tooth, and the relationship with surrounding tissues.
- Patient: patient’s knowledge, economic status, age.
- Conservation of tooth structure.
- Restorative material factors.
Tooth Prep Terminology
- Simple tooth prep: 1 surface involved.
- Compound tooth prep: 2 surfaces involved.
- Complex tooth prep: 3 surfaces involved.
- Internal wall: Prepared (cut) surface that does not extend to external tooth surface.
- Axial wall: Internal wall parallel to long axis of the tooth.
- Pulpal wall: Internal wall perpendicular to long axis of the tooth, occlusal to pulp.
- External wall: Prepared surface that extends to the external tooth surface.
- Floor/seat: Flat prepared wall perpendicular to occlusogingival occlusal force.
- Line angle: Junction of 2 planar surfaces.
- Point angle: Junction of 3 planar surfaces.
- Cavosurface angle: Angle of tooth structure formed by the junction of prepared wall and the external surface.
- Cavosurface margin: Junction of prepared wall and the external surface.
Classification of Tooth Prep
- Class 1:All pits and fissures restorations.
- Class 2: Proximal surfaces of posterior teeth.
- Class 3: Proximal surfaces of anterior teeth.
- Class 4: Proximal surfaces of anterior teeth involving incisal angle.
- Class 5: Gingival third of facial or lingual surfaces of all teeth.
- Class 6: Cusps of posterior teeth.