Objective: The purpose of this study was to evaluate root strengthening abilities of intracanal flowable composite, glass ionomer cement and conventional gutta percha obturation after apexification with mineral trioxide aggregate (MTA).
Methods: One hundred extracted human incisors were obtained in this in vitro analysis. Teeth were radiographed by a standardized operator to ensure no fractures or anatomical abnormalities were present. Two millimeters of the apical tip of each root were resected to remove any apical deltas and standardize the canal exit to the center of the root. Coronal access was made with #330 bur and an Endo-Z bur. A divergent open apex was prepared by instrumenting the canals with a #6 gates-glidden bur until this bur passed freely out the apex. Root diameter was measured by a standardized operator with digital calipers (General Tools, New York, NY, USA) in both a buccal-lingual and mesial-distal dimension. Teeth were stratified into similar dimension groups to identify and eliminate outliers of original tooth dimensions. Teeth of all dimension groups were included in all experimental and control groups. Working length was determined visually with a stainless steel hand file flush with the apical opening. A 4mm apical barrier of gray MTA was placed in each tooth (except for the negative control group). The teeth were mounted in a block of Jet acrylic (Lang Dental Wheeling, IL, USA) and subjected to fracture resistance using an Instron Universal Testing Machine.
Results: No statistically significant differences (P > .05) were found between any of the control or experimental groups.
Conclusions: It seems clear that with the current protocol, fracture resistance was minimally affected by preparation or restoration. We cannot conclude as to the reinforcing ability of the materials tested. The current protocol will need to be modified in future research to yield a statistically significant difference between the control groups before any conclusions about the experimental groups can be made