Robert S Roda DDS MS
The Purpose of Root Canal Therapy: to prevent and cure Apical Periodontitis
Goals of Endodontic Therapy
 Removal of Organic Substrate
 Prevention of Re-Infection
Post-Treatment Disease Etiology
1.Intraradicular Infection
2.Extraradicular Infection
Actinomyces israelii
Propionibacterium propionicum
3.Foreign Body Reaction
4.Cysts
Causes of Post-Treatment Disease
 Improper Diagnosis and Treatment Planning
 Inadequate Removal of Organic Substrate
 Inability to Maintain Asepsis
Etiology of Cracked Teeth
 Acute Trauma
 Iatrogenic
 TFO
Diagnosis
 Nomenclature Needed
 No Universal Agreement
 Multiple names for the same entities
Prognosis
 If the discontinuity in the tooth structure can be completely covered by the restoration, then the prognosis is improved.
 The question is: How far apically does the fracture progress?
Extent of Fracture
 Periodontal probing
 Radiograph
 Direct visualization

Radiograph
 rarely see fracture
 look for vertical perio defect
 “J”-shaped radiolucency
CBCT
 No better than radiographs
 Metal posts obscure detection
Direct visualization
 after endodontic access, C & S
 stain
 use microscope
 Surgical Exposure (Flap Diagnosis)
Bottom Line
Cracked teeth are unpredictable. Retain only if :
 other options are less desirable
 fracture is able to be covered
 occlusal forces can be minimized
“Epidemic” of Cracked Teeth
 Not an infection per se
 Allows introduction of bacteria to the periradicular tissues
 Leads to periradicular periodontitis
A “Modern Epidemic”
 Average Lifespan in 1900 was 45 years old
 Early to mid-20 th century o Life spans increased o Preventive dental care non-existent o Extensive tooth loss
 Current Status o People living longer o Keeping most all teeth o Effects of dental wear (including tooth fracture) increasing
Tooth Fracture
 Universal diagnostic system needed
 Diagnosis of ignorance in many cases
 Impossible to predictably treat with today’s technology

Prevention
 Minimize access prep size
 Minimize canal prep size
 Minimize forces of obturation
 Avoid intra-radicular posts
 Minimize occlusal stresses
Straight Line Access
Advantages:
 Greater visibility
 Minimizes Canal Curvature
 Minimizes Stress on Instruments
 Minimizes Risk of Separation
Disadvantages
 More tooth structure removed
 Increased risk of tooth fracture
Tapered Rotary Instumentation
 Select taper objective (.04 or .06)
 based on canal / root morphology
 Concern for root fracture
.04 vs .06 Taper
Concern: .06 Taper may over enlarge coronal preparation
.06 taper preparation
 use in large root with minimal curvature
 canal is better debrided
 deeper irrigant penetration
 canal is easier to obturate
 easier to prepare post space
 more removal of coronal tooth structure
.04 taper preparation
 use in thinner roots
 less likelihood of strip perforation
 more severe curvatures
 more flexible
 less likelihood of overstressing instrument
 less irrigant penetration
 harder to obturate
 more difficult to prepare post space

 Less removal of tooth structure
Obturation Fracture
 Compaction forces can result in lateral stress
 Potential for root fracture
 Both cold lateral and warm vertical compaction
Final Restoration
 Full Cuspal Coverage
 Minimize Delay
 No Post unless it is needed to retain a crown
 Frequent re-inspection and maintenance
The AAE Cracked Tooth Initiative
The Goal:
To eliminate cracked teeth as a major cause of tooth loss by 2050
The Plan:
Research Phase
Implementation Phase
Public Awareness Phase
Research Phase
 Diagnostic Consensus Conference
 Multidisciplinary
 Create Diagnostic Terminology
 Develop Universally Accepted Diagnostic Criteria
 Epidemiology
 Develop Surveys (Incidence and Costs to Society)
 Global Perspective
 Discover Critical Factors Affecting Incidence
Implementation Phase
Preventive Strategies
Immediate
 Minimize Removal of Tooth Structure During
 Operative Dentistry
 Endodontics
 Periodontics
Future
 Preventive Occlusal Therapies

 Regenerative Endodontics
Public Awareness Phase
 Advocate for Government/Private Funding
 Public Service Announcements
 Media Integration
 News
 Internet
 Movies/Television