Evaluation of the effect of different medicament agents and coronal barrier materials used in regenerative endodontic treatment on the fracture resistance of simulated immature teeth

The aim of this in-vitro study was to evaluate the effects of different intracanal medicaments (Ca(OH)₂, double antibiotic paste, triple antibiotic paste) and coronal barrier materials (MTA, Biodentine) widely used in regenerative endodontic treatment on fracture resistance in simulated immature teeth. One hundred and five extracted maxillary central teeth were sectioned 7 mm above and 10 mm below the cementoenamel junction. 5 teeth were the positive control group; they were prepared using Peeso Reamers from apical to coronal to simulate immature teeth without any access cavity preparation. Access cavities of the 100 teeth were prepared, and the canals were instrumented with Peeso Reamers. 10 teeth served as negative control group without medicament application. 90 teeth were randomly assigned into one of the following groups with respect to the intracanal medicament applied (n=30/group): Group 1. Calcium hydroxide (Jefix WooCal, Istanbul, Turkey); Group 2. A mixture of metronidazole, ciprofloxacin, and doxycycline (Triple Antibiotic Paste); Group 3. A mixture of metronidazole and ciprofloxacin (Double Antibiotic Paste). The samples were kept in an incubator at 37 ºC and >95% humidity for 4 weeks. Following irrigation, the specimens were divided into two subgroups according to the coronal barrier material applied (n=15/experimental group, n=5/negative control group): 1. ProRoot MTA (Dentsply Tulsa Dental, Tulsa, OK, USA) and 2. Biodentine (Septodont, Saint-Maur-des-Fosses, France). After 1 week of incubation at 37 ºC and >95% humidity, the samples' roots were covered with liquid latex and embedded in self-curing acrylic resin blocks. Each specimen was then subjected to fracture testing using Universal Testing Machine (UTC). The specimens examined under the stereomicroscope were evaluated as favorable and non-favorable according to the fracture modes. The data of fracture resistance test were analyzed by Kruskal Wallis test, the data of fracture modes were analyzed by Chi-square test. There was no significant difference in the fracture resistance and fracture modes between the groups of different intracanal medicaments and coronal barrier materials (p > 0.05). Different coronal barrier materials and intracanal medicaments used in our study can be used as alternatives to each other in terms of their effect on fracture resistance in immature teeth.