Principles of Cavity Preparation PDF

Elsevier Inc. items and derived items © 2006 by Elsevier Inc. OBJECTIVES OF CAVITY PREPARATIONS Elsevier Inc. items and derived items © 2006 by Elsevier Inc. Elsevier Inc. items and derived items © 2006 by Elsevier Inc. THE PASSION OF BEAUTY  PRINCIPLES OF CAVIT...

Elsevier Inc. items and derived items © 2006 by Elsevier Inc. OBJECTIVES OF CAVITY PREPARATIONS Elsevier Inc. items and derived items © 2006 by Elsevier Inc. Elsevier Inc. items and derived items © 2006 by Elsevier Inc. THE PASSION OF BEAUTY  PRINCIPLES OF CAVITY PREPARATION ▶ Factors affecting cavity preparations 1) Dental factors :- a) Diagnosis b) Dental anatomy ▶ A- Diagnosis:- Assessment of pulpal and periodontal status. Assessment of occlusal status Assessment of the relationship of a specific restorative procedures to other treatment planes ▶ B- Dental Anatomy :- Direction of enamel rods Thickness of the enamel and dentin Size and Position of the pulp Relations between the tooth and its supporting structures 2) Patient Factors :- a) Esthetic concern b) Economic concerns c) Medical conditions d) Age of the patient e) Caries risk assessment  3) Restorative Materials Factors:- a) The patient inputs( economic &esthetic) b) The ability of isolation c) The extend of the lesions  PRINCIPLES OF CAVITY PREPARATION Classification II- Mechanical principles I- Biological principles The Adequate Synchronization Between Biological And Mechanical Principles Will Result In Durable Restorations Elsevier Inc. items and derived items © 2006 by Elsevier Inc. BIOLOGICAL PRINCIPLES  I-BIOLOGICAL PRINCIPLES Definition Steps followed during cavity preparation to minimize irritation to the vital tooth pulp. Forms of biological principles: 1-Pulp protection. 2-Prevention of caries recurrence. 3-Aseptic procedures. 4-Protection of gingival and periodontal tissues.  1-PULP PROTECTION. The main functions of the pulp are : - a) Formation of the dentin b) Nutrition of the dentin c) Sensory responses d) Defensive due to irritations 1-Pulp protection. Against irritation: Mechanical Thermal Chemical  Against mechanical irritation: Avoid direct traumatic injuries to the Pulp. Avoid unnecessary pressure and wrong direction of instruments. Avoid cutting through recessional lines of the pulp chamber. Avoid over cutting of dentine and weakening of tooth structure. Avoid sharp line angles with the cavity.  Against thermal irritation: Avoid heat generation during cavity preparation. Avoid working without coolant. Avoid long time working. Against chemical irritation: Avoid using chemicals and caustics for toilet of the cavity. Avoid using air jet for a long time. 2-PREVENTION OF CARIES RECURRENCE. Removal of all carious enamel and dentine. Proper extension of cavity margins to self-cleansable area. Removal of all undermined enamel. Proper inclination of CSA with the type of restoration. 3-ASEPTIC PROCEDURES. Using a sterile and clean instruments. Application of rubber dam to keep the fields clean and dry. 4-Protection of gingival and periodontal tissues. Avoid overhang gingival margins of the restoration. Proper matricing during restoration of compound cavities. Proper wedging of the matrix. Controlled cutting to avoid instrument slippage and soft tissues injury. Avoid using irritating chemicals near the gingival margins of the cavity. Elsevier Inc. items and derived items © 2006 by Elsevier Inc. MECHANICAL PRINCIPLES  II- Mechanical principles Definition ∙ Steps followed during cavity preparation for preservation of the structural integrity of both the tooth and restoration by decreasing the tensile stresses to be within the physical tolerance of these structures. OBJECTIVES 1. Provision of adequate RETENTION to the restoration. 2. Provision of correct RESISTANCE against fracture to both the tooth and restoration. 3. CONSERVATION of maximum amount of tooth structure.  steps of cavity preparation are Initial stages Final 1- caries removal stages 2- pulp protection 1- outline form 3- secondary resistance and retention 2- primary resistance form forms 3- primary retention form 4- finishing external walls 4- convenience form 5- cleaning, inspecting, and desensitizing According to G.V. Black , principles of cavity preparation are:- 1- Outline form 2- Resistance form 3- Retention form 4- Convenience form 5- Removal of carious lesions 6- Finishing of the cavity 7- Toilet of the cavity  N.B.: → If the cavity is too deep and caries is extensive, step (4) can be interchanged with step (2) to determine: → 1. The cavity depth. 2. The extent of lesion.  Thank you Elsevier Inc. items and derived items © 2006 by Elsevier Inc.