Acessos endodônticos: o que todo endodontista deve saber / Endodontic accesses: what every endodontist should know

Introdução: Os acessos endodônticos minimamente invasivos (AEMI) surgiram com o intuito de, por meio da preservação de estrutura dentária, manter a resistência à fratura de dentes tratados endodonticamente. A partir do primeiro estudo, em 2010, vários trabalhos foram desenvolvidos buscando entender qual a influência dos AEMI na resistência à fratura de dentes tratados endodonticamente. No entanto, interferências coronárias causadas pelos AEMI poderiam prejudicar a realização dos procedimentos subsequentes à cavidade de acesso, como a localização, instrumentação, limpeza, descontaminação e obturação dos canais radiculares. Objetivo: Com base nessa premissa, a presente revisão teve como objetivo responder algumas perguntas para que o clínico entenda quais são as principais modalidades de AEMI, os impactos da sua abordagem no tratamento endodôntico e o verdadeiro papel do tratamento endodôntico na perda dos elementos dentários. Resultados: Considerando os dados disponíveis até o presente momento, faltam evidências robustas para apoiar a alegação de que os AEMIs preservem a resistência à fratura dos elementos tratados endodonticamente melhor do que nos dentes acessados de maneira tradicional. Além disso, cavidades de acesso minimamente invasivas podem interferir em outras etapas do tratamento endodôntico, podendo torná-lo imprevisível. Conclusão: Dessa forma, pode-se concluir que há uma falta de evidências que apoiem a utilização de cavidades de acesso minimamente invasivas na prática clínica de rotina e/ou no processo de formação de alunos de graduação e pós-graduação (AU).

Introduction: Minimally invasive access cavities emerged aiming to maintain the fracture resistance of endodontically treated teeth through the preservation of dental structure. Starting with the first study in 2010, several others were developed to evaluate the influence of minimally invasive access cavities in the fracture resistance of endodontically treated teeth. However, the coronal interference caused by those access cavities could impair the subsequent procedures of root canal treatment, such as the location, instrumentation, cleaning, disinfection and filling of the root canals. Objective: Based on this premise, the aim of the present review was to answer some questions so that the clinician knows the main modalities of minimally invasive access cavities, the impacts of this approach and the real role of endodontic treatment in the tooth loss. Results: Considering the available data, there is a lack of robust evidence in literature to support the claim that the minimally invasive access cavities preserve the fracture resistance of endodontically treated teeth better than the traditional one. In addition, these access cavities can interfere in other stages of endodontic treatment, making it unpredictable. Conclusion: Thus, it can be concluded that there is a lack of evidence to support the use of minimally invasive access cavities in routine clinical practice and/or in the process of training undergraduate and graduate students (AU).

Does the type of endodontic access influence in the cyclic fatigue resistance of reciprocating instruments?

INTRODUCTION: The aim of the present study was to compare the cyclic fatigue resistance of Reciproc R25 (R25) and Reciproc Blue R25 (R25B) instruments, after simulated clinical use in traditional (TradAC) and ultraconservative (UltraAC) endodontic access cavities. METHODS: Forty mandibular molars were randomly assigned into the following groups, according to the type of access and instrument to be used: TradAC and R25, TradAC and R25B, UltraAC and R25, and UltraAC and R25B. Teeth were accessed accordingly, and the root canals were prepared using "RECIPROC ALL" kinematics. The cyclic fatigue resistance of the forty used instruments was obtained measuring the time to fracture in an artificial stainless-steel canal. Ten brand new R25 and R25B were used as control groups. The fracture surfaces and the side cutting edges of the instruments were examined with a scanning electron microscope. Data were statistically analyzed using one-way ANOVA and post hoc Tukey tests with a significance level of P < 0.05. RESULTS: R25B instruments showed significantly higher cyclic fatigue resistance than R25, regardless of the access cavity type (P < 0.05). No differences were observed in the cyclic fatigue resistance between instruments without simulated clinical use and used in TradAC (P > 0.05). R25 and R25B used in UltraAC showed significantly lower cyclic fatigue resistance compared with the instruments used in TradAC and without simulated clinical use (P < 0.05). CONCLUSIONS: R25B files showed improved cyclic fatigue resistance than R25. The use of R25B and R25 files in mandibular molars with UltraACs decreased their cyclic fatigue resistance, compared with TradAC. CLINICAL RELEVANCE: The use of Reciproc and Reciproc Blue files in mandibular molars with ultra-conservative endodontic access cavities reduced their cyclic fatigue resistance. Clinicians should be aware about the reduced cyclic fatigue resistance of these files when used in mandibular molars with UltraAC, due to the synergistic effect of access angulation and severe curvature induced in the endodontic files.