Gate toward Operative Dentistry Dr. Hicham Nuaimi BDS, PG Dip in Operative and Esthetic Dentistry PGDip in Implantology MClin in Operative and Esthetic Dentistry

What are the objectives of Restorative Dentistry

Restorative Operation Non Cariogenic causes Abrasion / abfraction of tooth structure Erosion of tooth structure Cariogenic causes: Failure restorations Initial / recurring decay

What do We mean by Tooth Preparation? is the mechanical procedure for eliminating decay lesion and establish proper design for retention and resistance of dental restoration withdraw its functional and esthetical approach.

Categories for tooth preparation Eliminate decay lesion Function and Esthetic Protect the pulp Minimal invasive preparation Categories for tooth preparation

surface that does not extend to external tooth aspects Internal wall surface that does not extend to external tooth aspects Axial Wall is an internal wall that is parallel to the long axis of the tooth Pulpal Wall is an internal wall that is perpendicular to the long axis of the tooth.

is a prepared surface, which extends to the external tooth surface External Wall is a prepared surface, which extends to the external tooth surface Floor wall is a prepared wall, which is perpendicular to the occlusal forces (occluso-gingival), as pulpal and gingival walls.

is that portion of a prepared external wall consisting of enamel Enamel Wall is that portion of a prepared external wall consisting of enamel Dentinal Wall is that portion of a prepared external wall consisting of dentin.

is the junction of 3 plane surfaces of different orientation Line angle is the junction of 2 plane surfaces of different orientation along a line Point angle is the junction of 3 plane surfaces of different orientation

How can design our Preparation??

Classifications Black’s classification Charbeneu’s classification Sturdevant ’s classification Baume’s classification Mount and Hume s’ classification Classifications

Black’s Classification Class V Class III Class I Class II Class IV Class VI

Occlusal two-thirds of buccal and lingual surfaces Class I Posterior Teeth Occlusal surface Occlusal two-thirds of buccal and lingual surfaces Anterior Teeth Lingual surface

Class II Posterior Teeth proximal surfaces

proximal surfaces without removal of the incisal angle Class III Anterior Teeth proximal surfaces without removal of the incisal angle

Class III

on the proximal surfaces involves the incisal angle Class IV Anterior teeth on the proximal surfaces involves the incisal angle

Class IV

On the gingival third of the facial surface for both dentition. Class V On the gingival third of the facial surface for both dentition. Class VI Tips of cups and incisal edges of teeth for both dentition

Charbeneu’s classification

Modification of Charbeneu’s classification Class II: Cavities on single proximal surface of bicuspids and molars.

STURDEVANT ’S CLASSIFICATION Simple cavity cavity involving 1 tooth surface Compound cavity cavity involving 2 tooth surfaces Complex cavity cavity involving 2> tooth surfaces

Finn’s Modification For deciduous teeth

pits and fissures of the molar teeth Class i pits and fissures of the molar teeth buccal + lingual pits of all teeth Class ii proximal surface of molar teeth Class iii proximal surfaces of anterior teeth

Cavities of the proximal surface of an anterior tooth which involve the restoration of an incisal angle Class iv Cavities present on the cervical third of all teeth of all teeth including proximal surface where the marginal ridge is not included in the cavity preparation Class v

BAUME’S CLASSIFICATION

According to tooth surface Smooth surface cavities Pit and fissure cavities

Mount and Hume’s Classification They tried in 1998 to find classification according to conservative approach in the extent and complexity, which encourage tooth structure for healing

Size 1 involve minimally in dentin. Need for remineralization only Size 2 involve moderately in dentin. Need for restoration that supported by dentine. Tooth is strong no need for support Size 3 involve moderately in dentin, but the tooth is weakened according to splitting of cusps or incisal edges. Restoration need for support

bulk loss of tooth structure by caries extension Size 4 bulk loss of tooth structure by caries extension

INITIAL AND FINAL STAGES OF TOOTH PREPARATION Initial tooth preparation stage: Step 1: Outline form Step 2 Resistance form Step 3 Retention form Step 4 Convenience form

Final tooth preparation stage: Step 5 Eliminate any remaining infected dentin Step 6: Pulp protection, if indicated Step 7: Secondary resistance and retention forms Step 8: Procedures for finishing external walls Step 9: Final procedure--cleaning, inspecting sealing

Step 1 Remove weakened and unsupported enamel. Design the cavity wall to occupy the final restoration Remove weakened and unsupported enamel. Preserving cuspal strength Margins afford for good finishing

Step 2. Primary Resistance Form Design walls to shape the final restoration and enable restoration withstand without fracture either tooth structure or restorative materials. BY

keep appropriate enamel thickness for preventing fracture Primary Design create box shape at the floor that aids tooth structure to resist occlusal loading. create slightly round internal angles which reduce the stress concentration. restrict the extension in the external walls to get strong cusp and ridge areas keep appropriate enamel thickness for preventing fracture

Prepare round Internal Line angles

Step3: Primary Retention Form Is the form to obtain resistance of dental restorative from displacement during mastication forces.

Step4: Convenience Form. Is the step to provide a proper vision during decay removal.

Step 5: Remove any remaining enamel pit fissure infected dentin old Restorative material Remove any carious tooth Structure Step 5:

Cases for removal old restoration

negatively the esthetic result 2nd caries Default in restoration Symptomatic pulp

The ingress of noxious products & bacteria through microleakage Step 6: Pulp Protection Galvanic shock The ingress of noxious products & bacteria through microleakage thermal changes conducted through restorative materials ingredients of various materials

LINEAR USED FOR: protects the dentin from noxious agents fluids Some thermal protection LINEAR USED FOR: Initial electrical insulation

Mechanical preparation Secondary retention etching Mechanical preparation Step 7

Mechanical preparation Beveled Enamel Margins Groove Extensions pin, Amalgam pins steps, Slots

Etching Retention Enamel Wall Etching Dentin Treatment

Step 8: Procedure for Finishing the External Walls Finishing the preparation wall is the further development, when indicated, of a specific Cavo surface design & degree of smoothness or roughness that produces the maximum effectiveness of the restorative material being used.

Objectives: - 1) create the best marginal seal possible between the restorative material and the tooth structure. 2)afford a smooth marginal junction. 3) provide maximal strength of the tooth & the restorative materials.

Final preparation Cavo-surface angle degree of smoothness or roughness of wall Provide proper strength of restoration

Step 9: Final Procedure: Cleaning, Inspecting. & Sealing The usual procedure in cleaning is to decay free. Preparation of visible debris with warm water from the syringe & then to remove the visible moisture with a few light surges of air from the air syringe .

Thank You.