The effect of glide path preparation on the shaping ability of XP-endo® Shaper in simulated canals

Aims: To compare the shaping efficiency of the XP-endo Shaper with or without glide path preparation with sequenced Scout Race files in J-shaped resin blocks Material and Methods: Forty simulated J-shaped root canals were classified into two groups (n=20). While the root canals were shaped with XPS after a glide path was created with Scout Race files in Group 1, the same procedures were done without the glide path preparation in Group 2. The pre-and post-instrumentation images were taken and superimposed. Transportation value (TV), centering ability (CA) and the total amount of resin removed (TRR) was calculated by using the obtained images with Adobe Photoshop CS5 software. These parameters were calculated based on 18 reference points (9 inner/9 outer walls) with 1-mm intervals according to 3 sections (coronal, middle, and apical of the canals). The data were analyzed with Kruskal-Wallis and then Dunn's multiple comparison tests (p ≤ 0.05). Results: More resin was removed in Group 2 apical and coronal sections than in Group 1 (p=0.036). In Group 2, a higher transportation value was obtained in apical and middle sections compared to Group 1 (p<0.001). Group 1 showed a higher centering ratio in apical and middle sections than in Group 2 (p<0.001). The centering ability of the instruments was decreased in the curvature part (middle section) of the canals. Conclusions: Within the limits of this study, glide path preparation using Scout Race instruments improved the shaping ability of XPS instrument by leading to less transportation and maintaining centering ability.

A CBCT based digital analysis of shaping ability of Max Wire® alloy file in the treatment of large and curved root canals

Aim: To evaluate the limits of the shaping ability of MaxWire® alloy file in the treatment of pre-created large and curved root canals with different apical sizes by using cone-beam computed tomography (CBCT). Materials and methods: Forty-five permanent maxillary first molars with moderately curved palatal roots (20°-30°) were divided into three groups, and large root canals were created with apical diameter #35 (Group 1), #40 (Group 2) or #50 (Group 3) by using BioRace NiTi System. Then, they were reshaped with the MaxWire alloy file, XP-endo Shaper®. Canals were scanned before and after instrumentation by using the CBCT scanner. Canal transportation (CT), centering ratio (CR), % increased prepared area (PA), and % increased prepared outline (PO) at 2, 3, and 4 mm from the apex were calculated. Data were statistically analyzed at P < 0.05. Results: There was a significant difference in the mean increase in PO in all apical sizes and all three levels. At both 3 mm and 4 mm levels the maximum PA and PO were achieved in apical size 35, while at 2 mm level the maximum values were obtained in apical size 40. There was no statistically significant difference in CT and CR within groups at 2 mm distance from the apex. Conclusion: Max Wire alloy technology of this novel instrument makes it possible to clean and touch the dentin walls of large and curved root canals. Small FOV and small voxel size of CBCT could also be used in shaping ability studies in endodontics.

Differences in endodontic emergency management by endodontists and general dental practitioners in COVID-19 times

Abstract The aim of this study was to assess the differences, if any, between general dental practitioners (GDPs) and endodontists, in the diagnosis and treatment of endodontic emergencies during the worldwide outbreak of COVID-19. An online questionnaire was randomly sent by social media to clinicians in different countries from 24 April, 2020 to May 4, 2020. The survey consisted of a series of questions about demographic characteristics, endodontic emergency diagnoses, approaches to prevent aerosol formation, drug prescriptions in case of symptomatic irreversible pulpitis, and the ways in which dentists managed endodontic emergencies during the COVID-19 lockdown. A total of 1,058 dentists responded to the questionnaire; 344 (32.6%) of the participants were endodontists. Slightly less than half of the participants (n = 485, 45.8%) worked during the lockdown, but only 303 participants (28.6%) treated endodontic cases/emergencies. The responses showed agreement between endodontists and GDPs regarding the diagnosis of symptomatic irreversible pulpitis (SIP), symptomatic apical periodontitis (SAP), reversible pulpitis, and asymptomatic irreversible pulpitis (AIP). SIP and SAP were considered an emergency, whereas reversible pulpitis and AIP were not considered an emergency (p > 0.05). Non-aerosol-generating procedures and treatment approaches differed between the groups (p < 0.05). One-third of the participants did not use rubber dam (p > 0.05). Ibuprofen and amoxicillin-clavulanic acid were the most frequently prescribed drugs for pain associated with SIP. In conclusion, the most relevant findings in our survey were the differences between endodontists and GDPs in diagnosis, precheck triage, deep caries excavation procedures, and endodontic emergency pain relief strategies.

Effects of MTAD on the bond strength of bioceramic root canal sealer

Aim: The aim of this in-vitro study was to investigate the effects of MTAD (a mixture of doxycycline, citric acid, and a detergent) on the bond strength of AH Plus (Dentsply DeTrey GmbH, Konstanz, Germany) and EndoSequence BC sealer (Brasseler USA, Savannah, Georgia, USA). Materials & Methods: Eighty-four decoronated single-rooted human incisor teeth were prepared with Reciproc R25 files (VDW, Munich, Germany), and the canal was irrigated with 5 mL 1.3% NaOCl. The roots were randomly assigned to four groups (n = 21), according to the final irrigation protocol and sealer selection: Group 1: distilled water-AH Plus; Group 2: distilled water-EndoSequence BC; Group 3: MTAD-AH Plus; Group 4: MTAD-EndoSequence BC. For the final flush, in Groups 1 and 2, the root canals were irrigated with 5mL of distilled water; in Groups 3 and 4, 5mL of MTAD was used for 1 minute. After root canal obturation, specimens was embedded in an acrylic block and sectioned horizontally at three levels (coronal, middle, apical). Bond strength of sealer to root canal dentin was assessed via push-out test using a universal testing machine. Results: There were no significant differences among the groups in coronal and apical thirds. In the middle root third, Group 4 showed significantly lower push-out bond strength values than Group 2 (p=0.023). No significant difference was found between the two root canal sealers. Conclusions: Overall, MTAD final irrigation caused lower push-out bond strenght values than distilled water with no significancy.