Shaping ability of three nickel-titanium rotary instruments in simulated L-shaped canals: OneShape, Hero Shaper, and Revo-S.

BACKGROUND: Shaping ability of a file plays an important role during instrumentation in an endodontic treatment. This study aimed to compare the shaping ability of OneShape (OS), Hero Shaper (HS), and Revo-S (RS) instruments in simulated L-shaped canals. METHODS: Forty-eight simulated L-shaped canals were prepared to an apical size of 25 using OS, HS, and RS (all from Micro-Mega SA, Besançon, France), (n = 16 canals/group) systems. The amount of resin removed after each canal's preparation was measured and compared after producing a composite image made from the superimposition of pre and post-instrumented canals. Canal aberrations and the preparation time were also recorded. The data were statistically analysed by using ANOVA, Tukey, and Chi-square tests. RESULTS: One file fractured during instrumentation in the RS group. A significant difference was found at the apical end of the prepared simulated canal between the groups, with RS showing the least amount of resin removal from the inner side of the canals and HS showing the highest amount of resin removal from the outer side (P < 0.05). Regarding the total width of the canals after preparation, a significant difference was found between the groups at the apical end and the straight portion of the canals, and RS removed the least amount of resin at the straight portion of the canals (P < 0.05). No statistically significant differences were found between the different instruments regarding canal aberrations' incidence (P > 0.05). CONCLUSIONS: All of the files showed a tendency to straighten the canals, whereas OS files maintained the original canal curvatures well.

Intraoperative Blood Loss in Maxillofacial Trauma Surgery.

BACKGROUND AND OBJECTIVES: This study is aimed to assess the intraoperative blood loss of patients with maxillofacial bone fracture surgical intervention and to assess their need for blood transfusion. MATERIALS AND METHODS: In this retrospective study, intraoperative blood loss of 206 patients with facial bone fractures, who underwent surgery between 2017 and 2018, was retrieved. The patient's demographic information, the amount of blood loss, the type of facial bone fracture, and the patient's requirement for blood products were evaluated. RESULTS: The average amount of intraoperative blood loss was 77.6 ml, and none of the patients required a blood transfusion during the operation in this group of patients. maxillofacial bone fracture was most common in young males. The leading cause of fractures was motor vehicle accident. There was a reverse correlation between the patient's age and surgical blood loss, but there was no statistically significant relationship between the patient's gender and intraoperative surgical blood loss. CONCLUSION: The results of the present study show that preparation for blood transfusion in patients with maxillofacial traumatic bone fracture requiring surgery is uncommon if patients have no systemic disease or specific blood dyscrasias preoperatively.

Effect of Different Instrumentation Techniques on Vertical Root Fracture Resistance of Endodontically Treated Teeth.

STATEMENT OF THE PROBLEM: Vertical root fractures are catastrophic events that often result in tooth extraction. Many contributing factor are associated with increasing incidence of vertical root fracture. Root canal preparation is one of the predisposing factors which can increase the root susceptibility to vertical fracture. PURPOSE: The aim of this study was to compare the effects of three different instrumentation techniques on vertical root fracture resistance of endodontically treated teeth. MATERIALS AND METHODS: In this study, 120 freshly extracted mandibular premolar teeth of similar dimensions were decoronated and randomly divided into control (n=30), nickel-titanium hand K-file (HF, n=30), BioRaCe rotary file (BR, n=30), and WaveOne reciprocating single-file (WO, n=30) groups. After cleaning and shaping the root canals, AH26 was used as canal sealer, and obturation was completed using the continuous wave technique. The root canals were embedded vertically in standardised autopolymerising acrylic resin blocks, and subjected to a vertical load to cause vertical root fracture. The forces required to induce fractures were measured using a universal testing machine. ANOVA and Tukey's post-hoc test were used to analyse the data. RESULTS: All experimental groups showed statistically significant reductions in fracture resistance as compared with the control group. There was a statistically significant difference between the HF and BR groups. The WO group did not differ significantly from the HF group or the BR group. CONCLUSION: All three instrumentation techniques caused weakening of the structure of the roots, and rendered them susceptible to fracture under lesser load than unprepared roots. The fracture resistance of roots prepared with the single-file reciprocating technique was similar to that of those prepared with NiTi hand and rotary instrumentation techniques.