ANATOMY OF PULP AND ACCESS OPENING .pptx

ANATOMY OF PULP AND ACCESS OPENING

1. ANATOMY OF PULP & ACCESS OPENING

2. CONTENTS INTRODUCTION ANATOMY APICAL ROOT ANATOMY PULP OF MAXILLARY AND MANDIBULAR TEETH CLASSIFICATION OF CANALS ISTHMUS CLASSIFICATION ACCESS CAVITY PREPERATION OBJECTIVES PRINCIPLES STEPS ERRORS LAWS OF PULP CHAMBER BURS FOR ACCESS CAVITY PREPARATION

3. INTRODUCTION Pulp is a connective tissue which is present in central portion of the tooth As it is central portion it is also known as "Heart of the tooth" This connective tissue is highly vascularised and unique and dose not resemble any of the tissues in the human body

4. ANATOMY Each pulp organ resides in pulp chamber which is surrounded by dentin Total volumes of all pulp organs is 0.38cc, mean volume is 0.02cc Molar pulps are 3-4 times larger than incisor pulps Pulp organ: coronal pulp radicular pulp

5. APICAL ROOT ANATOMY

6. Pulps of maxillary teeth MAXILLARY CENTRAL INCISOR : Average length 22.5mm

7. MAXILLARY LATERAL INCISOR: Average length of root : 21mm

8. MAXILLARY CUSPID: Average root length :26.5mm, longest root

9. MAXILLARY FIRST PREMOLAR: Average length: 21mm

10. MAXILLARY SECOND PREMOLAR: Average length 21.6mm

11. MAXILLARY FIRST MOLAR: Average length 21.3mm

12. MAXILLARY SECOND MOLAR: Average length: 21.7mm

13. MANDIBULAR CENTRAL INCISOR: average length 20.8mm

14. MANDIBULAR LATERAL INCISOR: Average length : 22.6mm

15. MANDIBULAR CANINE: Average length: 25mm

16. MANDIBULAR FIRST PREMOLAR: Average length: 21.9mm

17. MANDIBULAR SECOND PREMOLAR: Average length: 22.3mm

18. MANDIBULAR FIRST MOLAR: Average length: 21.9mm

19. MANDIBULAR SECOND MOLAR: Average length: 22.4mm

20. CLASSIFICATION OF CANALS According to Vertucci’s canal configuration

21. ISTHMUS CLASSIFICATION

22. ACCESS CAVITY PREPERATION DEFINITION Access cavity preparation is defined as endodontic coronal preparation which enables unobstructed access to the canal orifices, a straight-line access to the apical foramen, complete control over instrumentation and accommodate obturation technique. According to Stephen Cohen, "it generally refers to the part of the preparation from the occlusal table to the root canal orifices."

23. OBJECTIVES According to R.E Walton:- Straight line access Improved instrument control Improved obturation Decreased procedural errors Conservation of tooth structure Minimal weakening of tooth Prevention of perforation Un-roofing the chamber and exposure of pulp horns Maximum visibility Location of canals

24. PRINCIPLES Outline form. Convenience form. Removal of remaining carious dentin and defective restorations. Toilet of the cavity.

25. ACCESS CAVITY PREPARATION IN ANTERIOR TEETH Outline form of central and lateral incisors are triangular with the base of the triangle towards the incisal edge and the apex towards the cingulum. Incisal edge

26. STEPS Entrance is gained through the middle of the middle third of the palatal surface Initial entrance Is prepared with a round bur at a high speed operated at a right angle to the long axis of the tooth. Only enamel is penetrated. The bur is positioned in a 45 degree to the long axis of the tooth then advanced to penetrate the pulp chamber. Removal of pulp chamber(deroofing) Removal of lingual shoulder

27. In canine the access cavity is oval

28. ERRORS Gouging Perforation Missed canal Ledge

29. In premolars: Maxillary: oval Mandibular: ovoid

30. Initial penetration is made parallel to the long axis of the tooth the exact centre of the central groove A round bur is used to open into the pulp chamber. The bur will feel "drop" when it reaches the pulp chamber Endodontic explorer is used to locate the orifice. A round bur is used to deroof the chamber Finishing and flaring of the cavity walls

31. ERRORS Under extended access cavity Over extended access cavity Perforation

32. ACCESS CAVITY PREPERATION IN MOLARS MB1 is located under the buccal cusp tip. MB2 is located mesial and palatal to MB1 (at the end of a comma tail). DB is located under the central fossa. Palatal is located at the junction of mesiopalatal cusp and oblique ridge. Point of entry is the centre of the occlusal table.

33. Access cavity outline in maxillary first molar and mandibular molar

34. ERRORS Over extended Underextended Failure to locate all the canals Perforation

35. LAWS OF THE PULP CHAMBER ANATOMY Law of centrality: The floor of the pulp chamber is always located in the centre of the tooth at the level of the CEJ. Location of CEJ: The distance from the external surface of the clinical crown to the wall of the pulp chamber is the same throughout the circumference of the tooth at the level of the CEJ, making the CEJ is the most consistent repeatable landmark for locating the position of the pulp chamber.

36. First law of symmetry: Except for the maxillary molars, canal orifices are equidistant from a line drawn in a mesiodistal direction through the centre of the pulp chamber floor. Second law of symmetry: Except for the maxillary molars, canal orifices lie on a line perpendicular to a line drawn in a mesiodistal direction across the centre of the pulp chamber floor.

37. Law of colour change: The pulp chamber floor is always darker in colour than the walls

38. LAW OF ORIFICE LOCATION The orifices of the root canals are always located at the junction of the walls and the floor. Law of orifice location 2: the orifices of the root canals are located at the angles in the floor wall junction. Law of orifice location 3: the orifices of the root canals are located at the terminus of the root development fusion lines

39. BURS FOR ACCESS CAVITY PREPARATION Access Opening Burs: They are round burs with 16 mm bur shank (3 mm longer than standard burs). Access Refining Burs :These are coarse grit flame-shaped, tapered round and diamonds for refining the walls of access cavity preparation. Surgical Length Burs: These are long 32 mm burs. They are useful in teeth which present problems with access and visibility. With there burs, visibility of cutting tip of instrument is increased because of displacement of handpiece away from incisal or occlusal surface of tooth..

40. CONCLUSION In conclusion, access cavity preparation is a vital step in root canal treatment which requires meticulous attention . Understanding the anatomy of pulp helps in better access cavity preparation.