Operative Dentistry department Motamiz OPRD 42 Lecture 1 WED 11-3-2020
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.