Case Model 1
Large Composite vs Crown
Case Summary
Posterior molar
Existing large MOD composite
Loss of both marginal ridges
No symptoms
No radiographic pathology
Patient reports clenching
1. Structure Assessment
Both marginal ridges absent
Dentin thickness moderate
Early crack line on mesiobuccal cusp
Periodontal support intact
Structural reserve: Moderate to Low
2. Force Assessment
Bruxism present
Heavy occlusal contacts
Lateral excursion contact on affected cusp
Force risk: High
3. Time Projection
Restoration age: 6 years
Fatigue accumulation significant
Compliance with night guard inconsistent
Time risk: Moderate to High
4. Long-Term Stability Projection
Under Preservation (large composite only)
Increased flexural strain
Elevated cusp fracture probability
High likelihood of future catastrophic fracture
Under Escalation (cuspal coverage)
Additional structural reduction required
Reduced flexural strain
Improved projected durability
5. Threshold Position
Projected force across projected time exceeds structural tolerance under preservation.
Threshold convergence present.
Decision: Crown indicated.