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Medication-related osteonecrosis of the jaw (MRONJ) is an uncommon and severe condition in patients who are receiving treatment with antiresorptive and/or antiangiogenic drugs, which are frequently used to treat or prevent cancer metastases. The treatment of MRONJ is challenging because the choice of a specific dental treatment depends on several factors, including the systemic condition of the patient, type and dosage of medications, and clinical and radiographic characteristics of the dental lesions. This case report describes the conservative endodontic treatment of an odontogenic infection in a patient at risk of developing MRONJ owing to bisphosphonate treatment. Endodontic retreatment was performed to control the odontogenic infection and avoid tooth extraction. Certain factors favor the use of a conservative approach, such as a localized and small infection, the absence of systemic factors (such as metabolic disorders or medications) that can impair bone healing, and good oral hygiene. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the influence of cervical preflaring on the choice of reciprocating file size (Reciproc system) and the difficulty in reaching the working length for Instrumentation of molar root canals. A total of 352 human molars were divided into 2 groups of 176 molars each. In the no preflaring (NPF) group, no cervical preflaring was performed. A reciprocating file (R25, R40, or R50) was selected, and instrumentation was performed in accordance with the manufacturer's recommendations. In the preflaring (PF) group, a file was selected, and cervical preflaring was performed with the use of No. 30/.10 or No. 25/.08 orifice shaper instruments. The clinician then selected a new reciprocating file or used the originally selected file to perform the instrumentation as done in the NPF group. Any changes in choice of file after preflaring were documented for the PF group, and the number of insertions required to reach the working length was recorded for both groups. After preflaring, the selected file was changed from R25 to R40 in 20.08% of canals, from R25 to R50 in 0.40% of canals, and from R40 to R50 in 42.14% of canals. After preflaring, 2.88% of the canals with an initial selection of an R50 file required an instrument with a larger diameter for effective preparation. There was a statistically significant difference between the groups for all file size changes (P < 0.001; x² test). The mean numbers of instrument insertions needed for the NPF and PF groups, respectively, were 4.09 and 2.42 (R25); 3.49 and 2.31 (R40); and 2.70 and 1.81 (R50). There was a statistically significant difference between the groups for all file sizes (P < 0.001; Kruskal-Wallis test). Under the conditions of this study, preflaring enabled a more suitable selection of reciprocating instrument, which, in turn, allowed for fewer insertions of the file up to the working length. [ABSTRACT FROM AUTHOR]

Introduction: The aim of this study was to evaluate the bending and cyclic fatigue resistance of Wave One Gold (WOG) and XI Blue (X1B) instruments when tested at body temperature (36°C ± 1°C) with and without subjected to an alloy cooling protocol. Materials and Methods: A total of sixty instruments (n=30) were tested. Forty instruments (n=20) were randomly selected and divided into two groups: body temperature (BT; n=20) and body temperature with cooling protocol (CP; n=20). Cyclic fatigue test was performed until fracture in a conventional stainless-steel device with water bath equipment to simulate body temperature. CP group instruments were subjected to 5 seconds of spray cooling every 30 seconds. Time to fracture was recorded in seconds. Resistance to bending at an angle of 45 degrees was evaluated using twenty instruments (n=10). Fractured surfaces were examined under scanning electron microscopy (SEM). Statistical analysis was performed at a 5% significance level. Results: There was no difference in the cyclic fatigue resistance between instruments in BT groups (P>0.05). Cooling protocol significantly increased the cyclic fatigue resistance of X1B instruments (P=0.0003) and WOG instruments (P=0.0003). Results: WOG instruments had a significantly lower cyclic fatigue resistance compared to X1B instruments in CP group (P=0.0001). There were no significant differences between the values of resistance increase presented by the instruments after cooling (P>0.05). Bending test presented no statistically significant differences between the tested instruments (P>0.05). Both instruments in both groups showed typical features of cyclic fatigue behavior under SEM. Conclusions: XI Blue #25.06 and WaveOne Gold #25.07 instruments presented similar cyclic fatigue resistance. The investigated clinical-replicable cooling protocol improved the cyclic fatigue resistance of the tested instruments, with XI Blue #25.06 presenting a greater cyclic fatigue resistance after cooling. Both instruments presented a similar bending capacity. [ABSTRACT FROM AUTHOR]

The Nickel-Titanium (NiTi) alloy was developed by the metallurgist William Buehler, and it has since been introduced into various fields of knowledge due to its properties of super elasticity and shape memory effect. The introduction of NiTi revolutionized endodontics as it enhanced safety in the biomechanical preparation of curved root canals, even in larger diameters. Its utilization offered advantages over stainless steel files. This study aimed to conduct a literature review of the advancements in the mechanical properties of the NiTi alloy used in the manufacturing of endodontic instruments. The bibliographical research was conducted from the electronic search of articles indexed in English in electronic databases (PubMed, Scopus, and Web of Science) without time restrictions. Articles were identified by crossing the following descriptors: NiTi, Nitinol, and Endodontics. The initial endodontic instruments made of NiTi were austenitic, and, therefore, less flexible. The incorporation of new manufacturing methods, such as electropolishing and heat treatments allowed the creation of instruments with higher amounts of martensitic phase, resulting in greater flexibility and enhanced fracture resistance and ensuring safety in treating curved canals. The introduction of NiTi in the manufacturing of endodontic instruments is associated with an improved safety and efficiency in biomechanical preparation compared to stainless steel files. Heat treatments enabled the production of more flexible and fracture-resistant instruments for curved canal preparation. [ABSTRACT FROM AUTHOR]