Endodontics

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This is a learning resource about endodontics (endodontology) which will focus on practical aspects. The project is an on-going work in progress and any contributions or feedback is welcome. For encyclopedic coverage of the topic, see the Wikipedia articles:

Treatment planning[edit]

It is sometimes said "Good surgeons know how to cut, better surgeons know when to cut, and the best Surgeons know when not to cut." Really, this adage can be applied to any irreversible treatment in medicine. Modern endodontic techniques mean that virtually any tooth can be root filled, but not everything that can be root filled should be root filled. Endodontic treatment takes time and effort for both operator and patient and should never be carried out in the absence of an evidence-based, overall restorative plan for the whole mouth.

Indications for RCT:

  • Irreversibly damaged or necrotic pulp +/- clinical and/or radiologic findings of apical periodontitis
  • Elective devitalization, e.g. prior to construction of a post crown, overdenture, doubtful pulp health prior to restorative procedures, likelihood of exposure when restoring a misaligned tooth, and prior to root resection or hemisection

Contra-indications for RCT:

  • Unrestorable and/or nonfunctioning teeth
  • Teeth with compromised periodontal status
  • Teeth with otherwise poor prognosis, uncooperative patients of persons in whom dental treatment cannot be carried out
  • Teeth of patients with poor oral condition that cannot be improved withing a reasonable time period

Frequently clinicians and patients are faced with the choice of either root canal treatment or dental extraction. This is a simplified version of an evidence-based decision making protocol to help with this decision (National Health Service, UK):

RCT possible Extraction
Medical history Fit and well Conscious dental treatment contra-indicated/ potential foci infection undesirable
Attendance pattern Regular Irregular
Patient reliability Good Poor/unknown
Patient motivation Good Poor
Oral hygiene Excellent or good Poor
Reason for RCT Trauma/acute minimal caries Gross caries, chronic pathology, crown fracture
General periodontal condition Excellent or good Poor
Number of missing teeth None, or only a few >5
Prosthesis No Yes
Tooth functioning Not in function
Existing coronal restoration Plastic, no cusp involvement Post crown, bridge abutment
Pulp Irreversible pulpitis, but not yet necrosis Dentoalveolar abscess, discharging sinus
Proposed coronal restoration Plastic, or crown without post Post crown
Full coverage crown accepted? Yes No
Radiographic pathology Early/none Large lesion with periodontal involvement
Existing RCT No Yes
Existing RCT status Successful Unsuccessful
Canal shape Favorable Unfavorable
Canal patency on radiograph Clear sclerosed
Root Straight Curved
Bone support >80% <50%
5 year survival chance Good Poor

Access cavity[edit]

EndoCheatSheet.png
Maxillary teeth Mean root length (mm) Number of roots Number of canals (%ge cases) Notes
Central incisor 23 1 1 Triangular access cavity. Start at cingulum, widen towards incisal edge. In the crown, pulp chamber is wider mesiodistally and flattened buccopalatally. At apex root canal is round.
Lateral incisor 22 1 1 Apical 3-4 mm of root has palatal curve
Canine 26 1 1 Longest tooth. Access cavity is rounder than upper 1 and 2 since only 1 pulp horn.
First premolar 21 2 1 (5%), 2 (90% B, P), 3 (5% MB, DB, P) Access cavity starts in center of occlusal groove, then widen buccopalatally to locate canal orifices under P and B cusp tips
Second premolar 21 1 1 (75%), 2 (75% B, P) Orifice centrally located, if not widen buccopalatally to look for 2 orifi under cusp tips. Separate canals usually reunite apically.
First molar 22 3 P longer than MB and DB, 3 (40% MB, DB, P), 4 (60% MB1, MB2, DB, P) Rhomboid access cavity, with distal edge on mesial aspect of transverse ridge. Palatal orofice largest and easiest to locate. DB and P orifi rounder, MB orofice ovoid since ribbon shape of MB root. MB2 between MB1 and P. Can use ultrasonic tip to locate MB2.
Second molar 20 3 P longer than MB and DB 3 (60% MB, DB, P), 4 (40% MB1, MB2, DB, P) Less chance of MB2, more chance of fusion of canals in 7 and 8's (1 Buccal 1 Palatal)
Mandibular teeth Mean root length (mm) Number of roots Number of canals Notes
Central incisor 21 1 1 (60%), 2 (40% B, L) Start cavity at base of cingulum, extend nearly to incisal edge to confirm presence/absence of 2 canals
Lateral incisor 21 1 1 (90%), 2 (10% B, L) Similar to central except may have distal curve
Canine 24 1 1 (90%), 2 (10% B, L) Access cavity starts at base of cingulum
First premolar 22 1 1 (75%), 2 (25% B, L) Access cavity is oval-shaped, wider buccolingually
Second premolar 22 1 1 (90%), 2 (10% B, L)
First molar 21 2 3 (65% ML, MB, D), 4 (35% ML, MB, DL, DB) Mesial canal orifices found under respective cusp tips. Larger distal orifice is more centered, if not then increased chance of 2 distal canals.
Second molar 20 2 2 (10% M, D), 3 (90% MB, ML, D) Increased chance of fused canals in 7s and 8s.

References and further reading[edit]

Access cavities table

  • Manogue M, Patel S, Walker R, 2013 The Principles of Endodontics 2nd Edition; Oxford; Oxford University Press
  • Garg N, Garg A, 2010; Textbook of Endodontics 2nd Edition; Jaypee Brothers Medical Publishers

Resources