Long-term evaluation of pulpotomized primary molars using MTA or Formocresol

Objective: To assess the long-term success rate of pulpotomy in primary molars with carious pulp exposure using Mineral Trioxide Aggregate (MTA) or formocresol (FC) as pulp dressing agents Methods: 64 primary molars of 35 children were treated by a conventional pulpotomy technique and randomly assigned to the MTA or FC group by the toss of a coin. Following removal of the coronal pulp and hemostasis, the pulp stumps were covered with an MTA paste in the experimental group. In the control group FC was placed with a cotton pellet over the pulp stumps for 5 minutes. The pulp stumps were then covered by zinc-oxide-eugenol. The teeth were covered with a stainless steel crown, with the exception of 8 teeth of both groups that were restored with an amalgam restoration. Thirty-three children with 62 teeth (29 treated with FC and 33 with MTA) were available for long-term clinical and radiographic evaluation. Follow-up ranged between 4 and 74 months. The mean follow-up time was 38 months with no difference between the groups. Twenty-nine teeth were followed till natural exfoliation (mean: 33 months). Failures were detected after a mean period of 16 months (range 4-30). Results: Success rate of pulpotomy was 97% for MTA (1 failure) and 83% for FC (5 failures). Eight teeth presented internal resorption. In four of them (two of each group) the resorption process stopped and the pulp tissue has been replaced by a radio-opaque calcified tissue. Pulp canal obliteration was observed in 55% (34/62) of the evaluated molars. This finding was detected in 58% (19/33) of the MTA and in 52% (15/29) of the FC group. Conclusion: MTA showed a higher (though not statistically significant) long-term clinical and radiographic success rate than formocresol, and can be recommended as a suitable replacement for formocresol.