Mineral trioxide aggregate used after root canal preparation favoured the occurrence of the apexification and periapical healing. The initial use of calcium hydroxide paste was not necessary for apexification to occur, and has shown to be strongly related to the extrusion of MTA and formation of barriers beyond the limits of the root canal walls.

The Tri Auto ZX was accurate to +/-0.5 mm in more than 80% of teeth following removal of root fillings.

This paper describes a case in which pulp therapy was provided in a fused maxillary primary central incisor in a 4-year-old patient with a history of fistula on the gingival mucosa. The tooth involved was larger than expected, suggesting fusion. The diagnosis of fusion was confirmed on radiographical examination. The clinical management of the case is described and the diagnosis and treatment discussed.

More intense and profound the infection, more severe is the dental destruction. The groups of residual roots showed the most severe bacterial infection compared to other groups.