The pulp
Inside the tooth, under enamel an dentin, is a soft tissue called the pulp Extends from the crown of the tooth to the tip of the roots where it connects to the tissues surrounding the root
Contains
blood vessels
nerves
connective tissue
Creates the surrounding hard tissues of the tooth during development The pulp is important during a tooth's growth and development.
Once a tooth is fully mature it can survive without the pulp, because the tooth continues to be nourished by the tissues surrounding it.
Function of the pulp :
1 - Nutrition
2 - Formation of dentine
3 - Innervation
4 - Defense mechanism
Pulp reactions to injurious stimuli:
Dentinal sclerosis
Reparative dentine
Inflammation
Necrosis
ROOT CANAL SYSTEM
The pulp chamber in the coronal part of a tooth consists of a single cavity with projections (pulp horns) into the cusps of the tooth.
The entrances (orifices) to the root canals are to be found on the floor of the pulp chamber.
In cross-section, the canals are ovoid, having their greatest diameter at the orifice or just below it.
The canals taper towards the apex.
The narrowest part of the canal is to be found at the apical constriction, which then opens out as the apical foramen and exits to one side between 0.5 and 1.0 mm from the anatomical apex .
Deposition of secondary cementum may place the apical foramen as much as 2.0 mm from the anatomical apex.
ACCESS CAVITY PREPARATION " DEFINITION "
Access cavity preparation is defined as: endodontic coronal preparation which enables unobstructed access to the canal orifices, a straight line access to apical foramen, complete control over instrumentation and to accommodate obturation technique.
It is a well established fact that success of endodontic therapy depends on the main three factors:
a. Cleaning and shaping
b. Disinfection
c. Three-dimensional obturation of the root canal system.
Before going for access cavity preparation, after evaluating other factors, a study of preoperative periapical radiograph is necessary with a paralleling technique.
