Basic Principles of Caries Treatment as Manifested in Cavity

Preparation Dr. Marwan A. Wahab Al Tamimi

B.D.SConservative Dentistry Department

Faculty of Dentistry University of Aden

Yemen

IntroductionThe treatment of a carious lesion will differ

according to it’s Manifestation ( clinical picture ),• Shallow Lesions will require a modification in the

oral hygiene of the patient which will permit them to be re-mineralized without any invasive procedures

• Deep Lesions will be treated through invasive procedures.

• Caries Lesions with pulp exposure, are treated with more complicated and extensive tooth lose.

Biological & Mechanical Principles of Cavity Preparation:- 1. Location of the Lesion.2. Amount of the lost tooth substance.3. The extension and amount of the lesion.4. The restorative material to be used.5. The presence of existing restoration.

General Principals of Cavity Preparations

According to G.V. Black• Establishing the Outline Form.• Establishing the Resistance Form.• Establishing the Retention Form.• Obtaining the Convenience Form.• Removing any remaining carious dentin.• Finishing the enamel walls.• Debridement.

Establishing the Outline Form

• It means carrying the margin of the cavity to the position it will occupy upon completion.

It depends on the following factors:

• Location and Extent of the lesion.• Healthy tooth structure.• Material of Restoration.• Tooth Morphology.

Resistance Form

Is defined as the architectural form given to a tooth preparation which enables both the restoration and the remaining tooth to

resist structural failure from occlusal load .

Resistance can be achieved through:-The walls must be smooth and thick.

Pulpal and gingival walls must be horizontal and plain.

The Buccal & lingual walls are perpendicular to occlusal while the mesial & distal are divergent to occlusal.

Pulpal Floor mesio-distally is flat and perpendicular to the long axis of the tooth

Retention Form• It refers to the features given to the

cavity preparation to prevent dislodgment of the restoration.

Retention Form can be achieved through:- The cavity should be deeper than wide or as deep as

wide.

Definitive angles. Dovetails extend into buccal, lingual and also by proximal grooves

Undercuts, Points and Grooves

• They are retention means made during cavity preparations which are usually made in dentin to avoid undermining the enamel.

• In Class I are made in facial & lingual walls.• In Class II are made in buccal & lingual walls of

the proximal box.• In Class V are made in incisal & gingival walls.• Never in the Axial or Pulpal.

• Obtaining the Convenience Form.

• Removing any remaining carious dentin.

• Finishing the enamel walls.

• Debridement.

Treatment of the Moderate Carious Lesions

• Moderate Lesions: lesions which have penetrated the enamel or has involved the dentin but not extended to the pulp.

• These lesions are differentiated from Deep Lesions, by it’s clinical penetration into the dentin and proximity to the pulp.

Mechanisms of Carious Removal• First, establish the Outline Form.• Second:-• determine the lateral penetration of caries by

using the dental probe.

• All undermined enamel is removed, which in turn will influence the final outline form.

• When considerable caries dentin is present, it should be removed either using large round bur on low speed handpeice or excavator.

Mechanisms of Carious Removal

• The color and texture of the remaining dentin serves as a guide to indicate proper removal.

• When the carious dentin is gone, the remaining surface will appear smooth and semi-polished, even though the dentin may still be discolored.

Cleansing The Prepared Surfaces

• Following cavity preparation the enamel and dentin surfaces are covered with a thin layer of debris, which very important to be removed. What and Why?

• This layer can be removed either by water – air syringe or by the use of medical solutions such as H2O2 of 3%.

Medicaments for Protecting Dentino-Pulpo Complex

For the Moderate Carious Lesion:-• Cavity Varnish.• Ca(OH).• Zinc Oxide Eugenol Cement.• Zinc Phosphate.• Poly Caboxylate Cement.• Glass Inomer Cement.

Treatment of the Deep Carious Lesions

Faced With A Deep Caries, The Operator Has Several Options

• For Emergency care, superficial carious dentin can be excavated and a temporary restoration is placed, any sharp edges of enamel is reduced with a diamond bur to avoid any injury to the tongue or cheek.

• With favorable prognosis the tooth can be permanently restored as though it were a Moderate Lesion.

Faced With A Deep Caries, The Operator Has Several Options

• If the lesion approximates the pulp, the pulp can be treated and a temporary restoration is placed, at a later period if the pulp health permits a final restoration is placed.

• Endodontic treatment can be followed by structural reinforcement. What is that?

• The tooth can be removed.

Faced With A Deep Caries, The Operator Has Several Options

Indirect Pulp Capping

• Is the procedure in which only the gross caries is removed and leave questionable carious dentin over the Pulpal area and seal it over.

• All the peripheral carious dentin is removed with large round bur or an excavator.

• Only teeth with deep caries that are free of symptoms ( pain , swelling ) should be selected.

• The remaining thin layer of caries in the base of the cavity is dried and covered with bactericidal dressing such as Ca(OH) or a thick mix of ZOE.

• The cavity is sealed with a durable interim restoration from 6 to 8 weeks.

• During the interim period the dentin undergoes remineralization and becomes harder.

Faced With A Deep Caries, The Operator Has Several Options

Direct Pulp Capping

• Is the procedure that should be limited to:-

• Accidental or traumatic exposures ( during cavity preparations ).

• Pin point carious exposures surrounded by sound dentin.

Steps

• Stop the bleeding.

• Apply Ca(OH) paste or powder over the Pulpal opening. ( site of exposure ).

• Fill the cavity preparation by a cement material which should provide a hermetic seal.

Prognosis

• Its preferable to wait for a period of 3 months.

• Remove the cement material and inspect the site of exposure for secondary dentin formation.

• If the pulp is vital with absence of inflammatory signs, the Prognosis is favorable to restore the tooth permanently.

Thank you for your Attention