Primary molar pulp therapy—histological evaluation of failure

Author(s): Waterhouse PJ, Nunn JH, Whitworth JM, Soames JV.
Journal: International Journal of Paediatric Dentistry
Volume (number): Volume 10
Month, Year: 2000
Major topic: Pulpal histology
Minor topic(s): Formocresol vs. Calcium Hydroxide pulpotomies
Type of Article: Research article
Purpose: This paper compares the histological, clinical, and radiographic features of primary molar teeth that showed evidence of clinical and/ or radiographic failure. Further histolgical findings were described in terms of reactionary dentin deposition and internal resorption of the dentin in these involved teeth..
Overview of method of research: The study evaluated 26 female and 26 male patients aged 3.3 to 12.5 years with primary molars requiring vital pulp therapy using either 20% Buckley’s formocresol for 5 minutes or Calcium hydroxide powder. Treated teeth were assessed clinically at 1 month, 6 months, and 12 months then annually thereafter for pain, defective restorations or signs of mobility. Radiographically these teeth were also evaluated for restoration failure, periapical pathology, and resorption. In cases of clinical or readiographic failure, the six teeth that exhibited failure were extracted and five were examined histologically because one tooth fractured during extraction.
Findings: Key points/Summary: Of the 5 teeth extracted, two teeth were from the formocresol group and three teeth were from the calcium hydroxide group. The formocresol specimens showed no dentin bridge formation but showed appositional dentin formation, whereas the other teeth showed dentin bridging in 4 of the 6 canals and the remaining two canals showed appositional dentin formation. Post extraction readiographs of the five teeth revealed pulpal obliteration in 4 of the 5 teeth.
Discussion: The extracted teeth demonstrated a consistent pattern of pulpal obliteration. Interestingly in the successful cases, calcific barriers and dentin bridging were evident in less than 25% of the cases. It was suggested that this may be related to the superimposition of healthy bone and soft tissue masking the bridging inside the pulp. Histologically, the failures may show more reactionary dentin formation as a result of an attempted repair process within pulp tissue. The author suggested that coronal leakage through a leaking restoration and penetration through a porous calcific barrier may cause a clinical failure. Also a tooth that is a poor candidate for a pulpotomy, i.e. an inflamed radicular pulp lacking proper hemorrhage control may lead to failure.
Recommendations/ Conclusions: The author makes the following recommendations based on the findings of this report: 1 Periodic radiographs are needed to monitor pulp healing after vital pulp therapy. 2. If hemorrhage persists after coronal amputation then a pulpotomy is a poor choice for treatment. And 3. A well sealed restoration is essential to prevent bacterial leakage.
Assessment of article: Interesting article with little scientific merit due to the small sample size. However, recommendations are useful.