This document discusses the principles of caries treatment and cavity preparation. It outlines how treatment differs based on lesion depth - shallow lesions may remineralize with hygiene, while deep lesions require invasive procedures. Cavity preparation considers lesion location/size, remaining tooth structure, and restorative material. Techniques are described for establishing outline, resistance, retention and convenience forms. Moderate lesions have dentin involvement but not pulp exposure, while deep lesions approximate the pulp. Options for deep caries include temporary fillings, pulp capping or removal. Indirect and direct pulp capping techniques aim to maintain pulp vitality and promote remineralization.

1. Basic Principles of Caries
Treatment as Manifested in Cavity
Preparation

2. Introduction
The 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.

3. 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.

4. 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.

5. 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.

6. 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.

7. 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.

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

9. Retention Form
• It refers to the features given to the
cavity preparation to prevent
dislodgment of the restoration.

10. 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

11. 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.

12. • Obtaining the Convenience Form.
• Removing any remaining carious
dentin.
• Finishing the enamel walls.
• Debridement.

13. 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.

14. 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.

15. 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.

16. 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%.

17. 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.

18. Treatment of the Deep Carious
Lesions

19. 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.

20. 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.

21. Faced With A Deep Caries, The
Operator Has Several Options
Indirect Pulp Capping

22. • 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.

23. • 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.

24. Faced With A Deep Caries, The
Operator Has Several Options
Direct Pulp Capping

25. • Is the procedure that should be limited to:-
• Accidental or traumatic exposures ( during
cavity preparations ).
• Pin point carious exposures surrounded by
sound dentin.

26. 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.

27. 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.

28. Thank you for your Attention