cavity prep for final yr

Dr. Fazal ur Rehman QaziBDS,FCPS

FCPS training Incharge

MDS Supervisor

Asst. Prof DIKIOHS, Dept of Op Dentistry

Dow University

Consultant Restorative Dentist,

FAZAL DENTAL PRACTICE

Khans Dental Clinic and KIHDE

Definition of Operative DentistryDefinition of Operative Dentistry

Operative dentistry is

the ART and SCIENCE of the

diagnosis, treatment, prognosis of defects of teeth which do not require full coverage restorations for correction.

Indication of Operative DentistryIndication of Operative Dentistry

Caries; Malformed, discolored,

or fractured teeth; Restoration replacement.

Program of Operative TreatmentProgram of Operative Treatment

Patient assessment Examination and diagnosis Treatment planning Pain control: local anesthetic Isolation of the operating field

Cavity preparation Matrix application Preparation of materials Insertion and carving of materials Finishing and Polishing


Cavity PreparationCavity Preparation

The mechanical alteration of a defective, injured, or diseased tooth in order to best receive a restorative material which will re-establish a healthy state for the tooth including esthetic corrections where indicated, along with normal form and function.

Cavity StructureCavity Structure

walls angles cavity

Classification of cavityClassification of cavity

Class I Class II Class III Class IV Class V Class VI

—G.V.Black in 1908

CavityCavity

Simple cavity: only one tooth surface is involved.

Compound cavity: two surfaces are involved.

Complex cavity: three or more surfaces are involved.

Class 1

Class 2

Class 1

Class 2

Class 3

Class 4

Class 5

Class 6

Stages and Steps in Cavity Preparation

Initial cavity preparation stage

Final cavity preparation stage


Step 1 Outline form and initial depth

Step 2 Primary resistance form

Step 3 Primary retention form

Step 4 Convenience form


Step 5 Removal of any remaining infected

dentin if indicated

Step 6 Pulp protection

Step 7 Secondary resistance & retention form

Step 8 Procedure for finishing external walls

Step 9 Final procedures

Outline Form and Initial Depth Ⅰ

Definition: placing the cavity margins in the positions they will occupy in the final preparation;

preparing an initial depth of 0.2~0.8 mm pulpally of the dentinoenamel junction position

Maxillary Class Ⅰ outline form

Mandibular Class Ⅰ outline form

Maxillary Class Ⅱ outline form

Mandibular Class Ⅱ outline form

Common Error

Outline Form and Initial Depth Ⅱ

Principles: without any exception all friable and/or weakened enamel should be removed

all faults should be included

all margins should be placed in a position to afford good finishing of

the margins of the restoration.

Outline Form and Initial Depth Ⅲ

Features: preserving cuspal strength

preserving marginal ridge strength

minimizing facio-lingual extension

using enameloplasty

connecting two close faults or cavities

restricting the depth of the preparation into dentin.

Primary Resistance Form ⅠPrimary Resistance Form Ⅰ

Definition: The shape and placement of the cavity

walls that best enable both the restoration and the tooth to withstand, without fracture, masticatory forces delivered principally in the long axis of the the tooth.

Primary Resistance Form ⅡPrimary Resistance Form Ⅱ

Principles: To utilize the box shape with a relatively flat floor to resist occlusal loading by virtue of being at right angles to mastication force;

To restrict the extension of the external walls (keep as small as possible) to allow strong cusp and ridge areas to remain with sufficient dentin support;

Primary Resistance Form ⅢPrimary Resistance Form Ⅲ

Principles:To have a slight rounding of internal line angles to reduce stress concentration in tooth structure;

To provide enough thickness of restorative material to prevent its fracture under load.

Primary Resistance Form ⅣPrimary Resistance Form Ⅳ

Feature: Box shape

Relatively flat floors

Inclusion of weakened tooth structure

Preservation of cusps and marginal ridges

Rounded internal line angles

Adequate thickness of restorative materials

Reduction of cusps for capping if indicated

Primary Retention Form ⅠPrimary Retention Form Ⅰ

Definition: The shape or form of the prepared

cavity that resists displacement or removal of the restoration from tipping or lifting forces.

In many respects retention and resistance form are accomplished in the same cutting procedure.

Primary Retention Form ⅡPrimary Retention Form Ⅱ

Principles: depending on the materials Amalgam restoration:

developing external cavity walls that converge occlusally and dovetail design

The devotail design provides retention form to the occlusal portion of the cavity.

The occlusal convergence of the walls offers retention in the proximal portion of the cavity against displacement occlusally.

Primary Retention Form ⅢPrimary Retention Form Ⅲ

Principles: depending on the materialsComposite restoration:

a mechanical bond between the material

and conditioned, prepared tooth structure.

Convenience Form ⅠConvenience Form Ⅰ

Conception: The shape or form of the cavity that

provides for adequate observation, accessibility, and ease of operation in preparing and restoring the cavity.

Convenience Form ⅡConvenience Form Ⅱ

Principles:

Allow access for caries removalAllow access for restoration placementAllow access to margins for finishing,

evaluation and cleaning

Convenience Form



dentin if indicated





Removal of any remaining infected Removal of any remaining infected dentin if indicateddentin if indicated

Definition: The elimination of any infected carious

tooth structure or faulty restorative material left in the tooth after initial cavity preparation.

Removal of dentinal caries using round burs and spoon excavators



dentin if indicated





Pulp protectionPulp protection

Using liners or bases

to protect the pulp or

to aid pulpal recovery or both.



dentin if indicated





Secondary resistance and retention Secondary resistance and retention forms Ⅰforms Ⅰ

Most compound and complex cavity preparations require additional resistance and retention form.

The exception being those preparations that are very conservative.

Secondary resistance and retention Secondary resistance and retention forms Ⅱforms Ⅱ

Mechanical forms

Cavity wall conditioning form

Mechnical form:

Proximal locks Proximal slots

Proximal locks

Slot on gingival wall



dentin if indicated



Step 8 Finishing external walls


Finishing the external walls ⅠFinishing the external walls Ⅰ

Definition: is the further development of a

specific cavosurface design and degree of smoothness that produces the maximum effectiveness of the restorative material being used.

Finishing the external walls ⅡFinishing the external walls Ⅱ

Objectives: To create the best marginal seal possible

between the restorative material and tooth structure;

To afford a smooth marginal junction; To provide maximum strength of both the

tooth and the restorative material at and near the margin.

The strongest enamel margin is that marginwhich is composed of full-length enamel rodsthat are supported on the cavity side by shorterenamel rods, all of which extend to sound dentin.

Finishing the external walls ⅢFinishing the external walls Ⅲ

The design of the cavosurface angle

The degree of smoothness of the wall

The design of the cavosurface angle: depending on the material

amalgam: 90°

composite: beveling 30°~ 40°



dentin if indicated





Final proceduresFinal procedures

cleaning inspecting varnishing conditioning

Matrix Application

Tofflemire Matrix System

Ivory Matrix System

Matrix retainer, Band & Wedge

Matrix in Retainer

Contour Matrix

Rounded instrumentsuch as a spoon excavator

Matrix on Tooth

Occlusal View

Wedge place

Contour Band

Ready for restoration

Armamentarium

Amalgam Capsule Amalgamator Squeeze Cloth Amalgam carrier

Activate Mercury

Insertion and carving

Class Ⅰ

Class Ⅱ

Armamentarium

Amalgam Condensers Anatomic Burnishers Carves

— Cleoid or Discoid

Check condenser fit

First increment

Start with the smallest condenser

Step condenser over mass

Continue adding increment

Condense toward walls

Use alternative instruments

Overpacked

Create initial grooves

Carve to margin

Enhance grooves

Remove flash

Final shape and burnishing

Completed restoration

Initial Increment

Initial Condensation

Lateral Condensation

Overpacking

Marginal Ridge Condensation

Condense to Margins

Create Occlusal Embrasure

Occlusal Embrasure

Removing Ridge

Removing Band

Flash & Excess

Moving Excess

Check with interproximal carve

Instrument on Tooth Structure

Completed Restoration

Rubber dam removal

Polishing

Dr. Fazal

Evaluate the restoration Class I

Verify that cavosurface margin can be seen

— Flash— Underfilled— Voids

Check the overall shape of the anatomy

— Look for bulky ridges that might be high in occlusion

Evaluate the restoration Class II

Check proximal contact

Check flash and overhangs proximally

Check underfill proximally

Check outline form

Check Occlusion

Evaluate carefully with marking paper or ribbon in Miller forceps

Check gently in centric occlusion

Check all excursive movement

cavity prep for final yr

Health & Medicine

cavity class

outline form

class v class

maxillary class

mandibular class

initial depth step

convenience form

primary retention form