Authors: Strindberg L.
Title: The Dependence of the Results of Pulp Therapy on Certain Factors.
Journal: Acta Odontol Scand
Date: Jan 1956
Citation: Volume 14, Supplement 21
Category: Success and Failure
Evidence-based Ranking: 2
Purpose/Objectives: To study a broad range of factors relative to RCT treatment and determine their influence on ultimate success or failure of the treatment.

Materials & Methods: 254 patients with 529 teeth with 775 canals were included. Teeth were treated with pulpotomy and RCT over a six year period and followed for a four year period and later. Success and failure were determined by a combination of clinical exams and radiological exams. Statistical analysis was preformed and the factors having a significant influence on success or failure were reported.

Results: 1. Age – No difference between younger (< 35) or older 2. Number of teeth treated – Higher success for 4 or less than for 5 or more 3. Pulpal anatomy – Higher success for 3 roots than 2 roots than 1 root; Higher success for teeth that could not be prepared to the apex than for those that could. 4. Pulp status – Higher success for necrotic pulps than for pulpitis. 5. Periradicular status – Lower success rates for teeth with periapical radiolucencies; The larger the area the lower the chance for success. 6. Apical resorption – Lower success for teeth with apical resorption. 7. Forms of pulpectomy – No difference between vital, paraformaldehyde or arsenical paste. 8. Antibacterial treatment – Larger numbers of sterile dressings did not increase success rate. 9. Clinical and technical complication – Presence of acute symptoms did not decrease success. Broken file fragments left in canal decreased success. 10. Canal preparation – Wider apical preparation led to higher success rate. 11. Root filling material – No difference. 12. Type of root filling – Pronounced overfilling decreased success. Poor adaptation or shrinkage of filling reduces success.

Author’s Conclusion: Many factors can influence the success and failure of root canal treatment.

Validity of Conclusion: Valid but possibly outdated.

Reviewer’s Comments: A well designed, long term study that took a huge effort to fulfill. At the time it was certainly extremely relevant.