The formocresol technique in young permanent teeth. A histopathologic study

Twenty-six extractions were performed at random among seventy-six young, permanent teeth, treated by the formocresol technique, between 5 and 20 months after treatment: twenty-one with penetrating caries (nine vital and twelve nonvital) and five healthy. As a control group, thirteen permanent teeth with penetrating caries were removed: seven vital and six nonvital. The histopathologic analysis compared pretreatment and posttreatment radiographic examinations. In the control cases, there was almost always inflammation and/or necrosis in the entire root canal. In the experimental cases, fibrosis and osteodentin predominated in the apical third, diminishing gradually near the cervical third. Inflammation and necrosis, very low in the apical third, increased similarly near the cervical third. This response seems to be a stage in a process of evolution in biologic scar healing. The complete cure must require a greater lapse of time than that of this experiment--around 10 to 12 months.