A retrospective study of root canal therapy in non-vital primary molars.

AIM: This study was performed to assess the clinical and radiographic success rates of a formocresol and zinc oxide eugenol (ZOE) primary molar root canal therapy (RCT) technique. The effects of this treatment on the permanent successors and on exfoliation times were also investigated.

MATERIALS AND METHODS: Study design: the retrospective study included 161 patients with 211 primary molars treated by RCT by a single operator in a private paediatric dental office in the Toronto area. Data were coded and entered into a Microsoft Excel database and analysis undertaken using SPSS software. Predominantly non-parametric tests were used to evaluate statistical differences (p < 0.05).

RESULTS: A clinical success rate of 90% (190/211) and a radiographic success rate of 77.3% (136/176) were obtained. Following RCT in a primary molar, enamel defects were found in 6.8% (7/103) of premolars, all of which occurred in first premolars, and in patients treated at a mean age of 54.1 months (p < 0.005). Treated molars exfoliated on average 7.6 months sooner than contralateral teeth (p < 0.005).

CONCLUSION: This formocresol and ZOE RCT is a viable treatment for necrotic primary molars and yielded very high clinical and acceptable radiographic success rates.