In Vitro Evaluation of a Recently Developed Rotary File: AF Rotary / Avaliação in vitro de um arquivo rotativo desenvolvido recentemente: AF Rotary

Objective: Aim of the present study is to evaluate mechanical properties of a newly developed rotary file, AF Rotary (Fanta Dental, Shanghai, China), and to compare these features with a worldwide spread rotary file, Protaper Gold F2 (PTG F2; Dentsply Maillefer, Ballaigues, Switzerland). Material and Methods: 60 AF Rotary 25.06 and 60 PTG F2 were divided in three groups of 20 files each. A group underwent to cyclic fatigue resistance tests, second group underwent to torsional resistance tests, third group underwent to bending tests. The statistical analysis was performed using t student test with significance level set at 95% (p < 0.05). Results: AF Rotary showed significantly higher torsional resistance and cyclic fatigue resistance (p < 0.05) when compared to the PTG F2. AF Rotary also showed significantly lower bending resistance (p < 0.05) when compared to the PTG F2. Conclusion: Therefore, within the limitations of this study, the results show better performances for AF Rotary compared to PTG F2 regarding the cyclic fatigue test, the torsional test and the bending test. Since the PTG F2 is a commonly used and widely investigated instrument it could be possible to state that the AF Rotary exhibits remarkable in vitro performances. (AU)

Objetivo: O objetivo do presente estudo é avaliar as propriedades mecânicas de uma lima rotativa recém-desenvolvida, AF Rotary (Fanta Dental, Shanghai, China), e comparar essas características com uma lima rotativa mundialmente difundida, Protaper Gold F2 (PTG F2; Dentsply Maillefer, Ballaigues, Suíça). Material e Métodos: 60 AF Rotary 25.06 e 60 PTG F2 foram divididos em três grupos de 20 arquivos cada. Um grupo foi submetido a testes de resistência à fadiga cíclica, o segundo grupo foi submetido a testes de resistência à torção, o terceiro grupo foi submetido a testes de flexão. A análise estatística foi realizada por meio do teste t student com nível de significância de 95% (p <0,05). Resultados: AF Rotary apresentou resistência torcional e resistência à fadiga cíclica significativamente maiores (p <0,05) quando comparado ao PTG F2. AF Rotary também apresentou resistência à flexão significativamente menor (p <0,05) quando comparado ao PTG F2. Conclusão: Portanto, dentro das limitações deste estudo, os resultados mostram melhores desempenhos do AF Rotary em relação ao PTG F2 no que diz respeito ao teste de fadiga cíclica, ao teste de torção e ao teste de flexão. Uma vez que o PTG F2 é um instrumento comumente usado e amplamente investigado, pode-se afirmar que o AF Rotary exibe desempenhos in vitro notáveis. (AU)

Torsional Resistance of Two New Heat Treated Nickel Titanium Rotary Instruments: An in Vitro Evaluation

Abstract Objective: To evaluate the difference in torsional resistance, angular deflection and fragment length between two new rotary instruments: AF Blue S4 and S-One. These files share all features except cross-sectional design. Material and Methods: A total of 40 new Nickel-Titanium instruments of 25 mm in length were tested in this study and divided in two groups: 20 AF Blue S4, tip 25 and constant 6% taper and 20 AF-Blue S4 tip 25 and constant 6% taper. The torsional test was performed by the use of a torque recording endodontic motor (KaVo, Biberac, Germany). Torque to Fracture (TtF), Angular Deflection (AD) and Fragment Length (FL) was recorded for each instrument. To ensure an immovable block at 3mm of the instrument tip, an auto-polymerizing resin (DuraLay; Reliance Dental Mfg Co, Worth, IL) was used. Each file was rotated clockwise at a speed of 300 rpm until fracture occurred. Results: Group A (AF Blue S4) showed higher TtF and AD than Group B (S-One), and statistical analysis found significant differences between the two instruments (p<0.05). The mean values for FL showed no significant differences (p>0.05) between the two instruments. Conclusion: The AF Blue S4 seems to have a higher resistance to torsional stress in vitro. Clinically, the use of AF Blue S4 could be safer in narrow canals.

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.

Efficacy of sonic and ultrasonic irrigation devices in the removal of debris from canal irregularities in artificial root canals

Abstract Objective To evaluate the efficacy of different sonic and ultrasonic devices in the elimination of debris from canal irregularities in artificial root canals. Materials and Methods A resin model of a transparent radicular canal filled with dentin debris was used. Five groups were tested, namely: Group 1 - ultrasonic insert 15.02; Group 2 - ultrasonic insert 25/25 IRRI K; Group 3 - ultrasonic insert 25/25 IRRI S; Group 4 - sonic insert 20/28 Eddy on a vibrating sonic air-scaler handpiece; Group 5 - 20.02 K-file inserted on a Safety M4 handpiece. Two different irrigants (5% sodium hypochlorite and 17% EDTA) and 3 different times of activation (20, 40, and 60 seconds) were tested. Means and standard deviations were calculated and statistically analyzed with the Kruskal-Wallis and Wilcoxon tests (p<0.05). Results No statistically significant differences were found between the two irrigants used. Group 4 removed more debris than the other groups (p<0.05). Groups 1, 2, and 3 removed more debris than group 5 (p<0.05). A statistically significant difference (p<0.05) was found for the time of activation in all groups and at all canal levels, except between 40 and 60 seconds in group 4 at coronal and middle third level (p>0.05). Conclusions No significant differences were found between 5% sodium hypochlorite and 17% EDTA. When the time of activation rises, the dentin debris removal increases in all groups. Both sonic and ultrasonic activation demonstrate high capacity for dentin debris removal.

New Technologies to Improve Root Canal Disinfection

Abstract Effective irrigant delivery and agitation are prerequisites to promote root canal disinfection and debris removal and improve successful endodontic treatment. This paper presents an overview of the currently available technologies to improve the cleaning of the endodontic space and their debridement efficacy. A PubMed electronic search was conducted with appropriate key words to identify the relevant literature on this topic. After retrieving the full-text articles, all the articles were reviewed and the most appropriate were included in this review. Several different systems of mechanical activation of irrigants to improve endodontic disinfection were analysed: manual agitation with gutta-percha cones, endodontic instruments or special brushes, vibrating systems activated by low-speed hand-pieces or by sonic or subsonic energy, use of ultrasonic or laser energy to mechanically activate the irrigants and apical negative pressure irrigation systems. Furthermore, this review aims to describe systems designed to improve the intracanal bacterial decontamination by a specific chemical action, such as ozone, direct laser action or light-activated disinfection. The ultrasonic activation of root canal irrigants and of sodium hypochlorite in particular still remains the gold standard to which all other systems of mechanical agitation analyzed in this article were compared. From this overview, it is evident that the use of different irrigation systems can provide several advantages in the clinical endodontic outcome and that integration of new technologies, coupled with enhanced techniques and materials, may help everyday clinical practice.

Resumo A irrigação do canal radicular é coadjuvante na desinfecção e remoção de debris, contribuindo para o sucesso do tratamento endodôntico. Este artigo apresenta uma visão geral das tecnologias atuais indicadas para melhorar a limpeza e desbridamento do canal radicular. Foi realizado um levantamento bibliográfico eletrônico no site Pubmed utilizando palavras-chave específicas ao tema a fim de abordar literatura relevante. Após busca eletrônica, artigos completos foram revisados e os mais apropriados ao tema foram incluídos nesta revisão. Diferentes sistemas de ativação mecânica foram considerados: agitação manual com cone de guta-percha, instrumentos e escovas endodônticas, sistemas de vibração ativados por peças manuais em baixa rotação ou por energia sônica e subsônica, ultrassom, laser, assim como sistemas de irrigação que utilizam pressão apical negativa. Além disso, esta revisão descreve outros meios indicados para ampliar a descontaminação endodôntica por meio de agentes químicos como ozônio e desinfeção por meio de luz. A ativação ultrassônica do hipoclorito de sódio ainda permanece o padrão ouro e nos estudos é usada como controle na comparação aos demais sistemas que empregam agitação mecânica. A presente revisão mostra vantagens de diversos sistema de irrigação e associações entre eles, podendo aumentar a efetividade da irrigação endodôntica.