Operative Dentistry

department

Motamiz OPRD 42

Lecture 1

WED 11-3-2020

Management of deep

carious lesions

Dental caries

- Is a progressive infectious microbial

disease of the calcified tissues of the

teeth characterized by demineralization

of the inorganic component and

destruction of the organic substance.

- It is the most prevalent disease

affecting the modern human race

- The major problem with carious lesions is that

once it starts, it progresses and the resultant

effect persists throughout life even though it

has been treated.

- The tooth st affected by it / or removed during

cavity prep. can’t regenerate.

- The severity of the disease dictates the strategy

applied by the operator to overcome it.

- The techniques used to confront the lesion may

vary from simple preventive measures to more

serious and complicated vital pulp therapy

technique.

Management of a deep carious lesion constitute a real

challenge for:-

- The skill

- Knowledge

- Experience

- Armamentarium

- Professional capabilities of the operator.

Preservation of pulp vitality and protection against

further insults are the main concern of vital pulp therapy.

Pulp – dentin organ reacts to the carious process as early

as starting of the lesion in enamel.

1- Biological irritation from the bacteria and their toxins.

2- Chemical irritation from acids.

3- Physico-mechanical irritation resulting from the gradual diminution of the effective dentine bridge due to the advancing carious process

The irritation of carious process results from three

distinct causes:

1- Type of decay, whether acute or chronic.

2- Duration of the decay process.

3- Depth of the cavity ( involvement).

4- Number and pathogenicity of micro-organisms.

5- Tooth dentinal resistance.

6-The individual reaction of pulp dentin organ

Factors guiding the reaction of pulpo-dentinal

organ to caries process

Acute decay

Chronic decay

- Causes rapid destruction of the tooth St. The longer the acute lesion

remains untreated, the more the effects on the pulpo-dentinal organ.

Extensive acid production and virulence of the micro-organisms

makes longer acute caries very destructive to tooth and inducing pulp

exposure.

- The longer the duration of the process, the greater the chances for

repair provided that the pulp tissue is not directly involved .Although

chronic caries is considered to be irritant in regards to its microbial

content, yet, as long as chronic caries is separated by sound /

reparative dentine from the under lying pulp, the carious process can

stimulate repair in Pulp tissue.

Acute decay

Chronic decay

2-Duration of the decay

3-Depth of the decay ( involvement) :-

The deeper is the carious process, the greater the intensity of

irritation and the greater the possibility for pulpal destruction.

A- The actual depth:- the distance between CSA and cavity floor

(depth of cavity in enamel and dentin). i.e. the amount of tooth

structure clinically destructed by the carious process.

B- The clinical cavity depth:- the thickness of the dentin bridge

separating the pulp from the floor of the cavity.

- The determination of the remaining amount of dentin bridge is

more reliable evaluation. which is the protective separation of

dentine overlying the pulp.

C- The effective depth:- it is the most important cavity

depth → it expresses the length of the pathway of

irritants to the pulp. So, effective depth is termed.

Is the dentin bridge thickness along the course of

dentinal tubules.

The No. and Pathogenicity of the bacteria invading the carious

dentine determines to great extent the activity of the lesion in terms

of acuteness or chronicity. The type and metabolic activities of the

bacteria in the carious lesion affects the rate of demineralization.

5-Tooth dentinal resistance:- Resistance of dentine to spread of decay is affected by:- - Dentin Thickness:- through which the caries pass to initiate its

effect.

- Permeability of dentinal tubules.

- Solubility of dentin in acids, which is controlled by its content of

calcium and fluoride.

- Architecture of dentin & tubular arrangement.

4-Number and pathogenicity of micro-organisms:-

6-The individual reaction of the pulp-dentine organ:- The ability of the tissues to defend the carious process differs from

case to another . This is due to individual variations which are

related to:-

- The differences in age and the general health of pt.

- The structural and periapical condition of the affected tooth.

- The cellularity & vascularity of the pulpal tissues and immune

response.

This makes the standardization of the reaction of the pulp – dentine

organ to decay is difficult the lack of correlation between the

irritant cause and its tissue effects. This is called lack of cause –

effect relationship.

Reaction of P – D organ ranges from a healthy reparative reaction

to an unhealthy reparative reaction / pulp destruction.