Endodontic techniques with Nickel Titanium instruments: analysis of quality and efficiency of instrumentation in primary molars / Técnicas endodônticas com instrumentos de Níquel Titânio: análise da qualidade e eficiência da instrumentação em molares decíduos

ABSTRACT Objective: The purpose of the present in vitro study was to evaluate the efficiency of three different instruments in the root canals of artificial primary molars as well as the quality of the fillings. Methods: Sixty artificial primary molars were divided into three groups of 20 teeth. Each group was submitted to a different technique: Group 1 - conventional manual technique using Kerr files; Group 2 - manual technique with nickel-titanium files; Group 3 - NiTi rotary technique. The root canals were filled with calcium hydroxide paste. Aspects such as homogeneity of the fillings, taper and flowability of the preparations were considered comparatively to assess the quality of the instrumentations. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the efficiency of the preparation of the root canal considering the preparation times of them. Results: All three techniques were equally effective at shaping the root canals of primary teeth. The working time was shorter with the rotary instrument (p=0.000). In the pairwise comparisons, working time was shorter with the rotary instrument compared to the manual techniques with steel files (p=0.000) and NiTi files (p=0.000). Comparing the manual techniques, the working time was shorter with NiTi files compared to steel files (p=0.011). Moreover, less variability in the preparation time was found when the rotary instrument was used. Conclusions: The mechanized rotary method led to a shorter operating time in comparison to the manual techniques and is therefore a preferable option for the preparation of the root canals of primary teeth.

RESUMO Objetivo: Avaliar a eficiência de três instrumentos diferentes nos canais radiculares de molares decíduos artificiais, bem como a qualidade das obturações. Métodos: Sessenta molares decíduos artificiais foram divididos em três grupos de 20 dentes. Cada grupo foi submetido a uma técnica diferente: Grupo 1 - técnica manual convencional com limas Kerr; Grupo 2 - técnica manual com limas de níquel-titânio; Grupo 3 - Técnica rotatória de níquel-titânio. Os canais radiculares foram preenchidos com pasta de hidróxido de cálcio. Aspectos como homogeneidade das obturações, conicidade e fluidez das preparações foram considerados comparativamente para avaliar a qualidade das instrumentações. Os testes não paramétricos de Kruskal-Wallis e Mann-Whitney foram utilizados para comparar a eficiência do preparo do canal radicular considerando os tempos de preparo dos mesmos. Resultados: Todas as três técnicas foram igualmente eficazes na modelagem dos canais radiculares. O tempo de trabalho foi menor com o instrumento rotatório (p=0,000). Nas comparações pareadas, o tempo de trabalho foi menor com o instrumento rotatório em comparação com as técnicas manuais com limas de aço (p=0,000) e limas de NiTi (p=0,000). Comparando as técnicas manuais, o tempo de trabalho foi menor com as limas de NiTi em comparação com as limas de aço (p=0,011). Além disso, foi encontrada menor variabilidade no tempo de preparo quando o instrumento rotatório foi utilizado. Conclusão: O método rotatório levou um menor tempo operatório em comparação com as técnicas manuais e, portanto, é uma opção preferível para o preparo dos canais radiculares de dentes decíduos.

Antimicrobial Photodynamic Therapy in the Endodontic Treatment of Deciduous Teeth: In Vivo Pilot Study

Abstract Objective: To evaluate the Antimicrobial Photodynamic Therapy (aPDT) in infected deciduous teeth by quantifying the viable bacteria in root canal treatment. Material and Methods: Radicular canal cultures were collected (n= 10). Four intra-canal samples were collected at four different times in each of the sampled teeth, as follows: Time 1 (T1), baseline: After opening the pulp-chamber; Time 2 (T2): After application of aPDT; Time 3 (T3): After mechanical, chemical manipulation; Time 4 (T4): After a second application of aPDT. The aPDT was performed with a 4J/cm energy low-intensity diode, together with 0.005% methylene blue as a photosensitizer. The clinical specimens were taken to the laboratory for a bacteria count (colony forming units) and the results were statistically analyzed using the Friedman and Wilcoxon tests, with a significance level of α=0.05. Results: Statistical differences were seen between the numbers of bacteria at times T1-T2, T1-T3 and T1-T4 on the cultivated plates. However, no significant statistical differences were observed between the number of bacteria in samples T2-T3, T2-T4 and T3-T4. Conclusion: Antimicrobial photodynamic therapy can be a good co-adjuvant in root canal decontamination of necrotic primary teeth.

Agreement Between Working Length Measurements in Primary Teeth Obtained by Radiographs or Apical Locators

Abstract Objective: To perform an in vivo evaluation on the agreement between measurements of working length obtained by conventional radiographic examinations and an apex locator in deciduous teeth with or without root resorption. Material and Methods: Nine canals of teeth from children ranging from 3 to 5 years old were selected. Endodontic access was performed with a spherical diamond tip, the pulp was removed with Kerr-type steel files, and the canal was irrigated with 1% sodium hypochlorite. A file, compatible with the channel gauge, was then used to measure the length of the root canal with the apex locator. Conventional radiographs were also performed and, using a millimeter endodontic ruler, the length of the canal was determined. The differences between the measurements obtained between the two methods were analyzed using the Student's t-test. Results: The mean canal length for conventional radiography was 9.83 mm and 9.67 mm for the apex locator. The results of this study did not show significant differences (p=0.641), independent of the presence or absence of physiological root resorption. Conclusion: The similarity in measurements obtained with X-ray or an apex locator indicates that it is not necessary to use X-rays as a complement to obtain the working length. The use of the apex locator can provide a quicker treatment, reducing the clinical time and stress of the child.