Andréa Cruz Câmara

Evaluation of the centreing ability of the ProTaper Universal™ rotary system in curved roots in comparison to Nitiflex™ files

The aim of the present study was to assess the centreing ability of the ProTaper Universal rotary system in curved roots in comparison to Nitiflex files, by means of preoperative and postoperative imaging of a cross-section of the apical third. Twenty mesiobuccal canals of human first mandibular molars with a degree of curvature ranging from 35 degrees to 60 degrees were divided into two groups of 10 specimens each: group 1, ProTaper Universal rotary system; group 2 (control), Nitiflex files. All instruments produced morphological alterations. The Students t-test and Kruskal-Wallis test showed that the differences were not statistically significant, except for the specimens instrumented by Nitiflex file #30. The ProTaper Universal showed the capacity for producing centered preparations in curved and thin root canals with low proportions of apical deviation.

In vitro antimicrobial activity of 0.5%, 1%, and 2.5% sodium hypochlorite in root canals instrumented with the ProTaper Universal system.

OBJECTIVE The purpose of this in vitro study was to evaluate the antimicrobial activity of 0.5%, 1% and 2.5% sodium hypochlorite in root canals instrumented with the ProTaper Universal system. STUDY DESIGN Fifty human mandibular premolar teeth with single root canals were infected with a mixture of C. albicans, P. aeruginosa, E. faecalis, and S. aureus. The specimens were randomly divided into 5 groups with 10 root canals each according to the irrigant used: group 1: 0.5% NaOCl; group 2: 1% NaOCl; group 3: 2.5% NaOCl; group 4 (positive control): 0.85% sterile saline solution; group 5 (negative control, without microorganisms): 0.85% sterile saline solution. All root canals were instrumented with the ProTaper Universal system. The assessment of the antimicrobial action of the irrigant was performed before the biomechanical preparation (0), and after instrumentation with S1 (1), S2 (2), F1 (3), F2 (4), and F3 (5) files. RESULTS All positive control samples showed microbial growth, whereas negative control samples showed no microbial growth before the biomechanical preparation and after the instrumentation with S1, S2, F1, F2, and F3 files. The microorganisms were eliminated after the instrumentation with S1 file in all tested irrigants, except for 1 sample in S1 at 0.5% NaOCl which showed positive growth. There was no significant statistical difference (P = 1.000) among the tested irrigants. CONCLUSION Sodium hypochlorite, at all tested concentrations, was effective in eliminating C. albicans, P. aeruginosa, E. faecalis, and S. aureus in combination with the NiTi rotary instrumentation with the ProTaper Universal system.

Comparison of Smear Layer Removal Using the Nd:YAG Laser, Ultrasound, ProTaper Universal System, and CanalBrush Methods: An In Vitro Study

INTRODUCTION The aim of this study was to compare the efficacy of the Nd:YAG laser, ultrasound, the ProTaper Universal system (Dentsply Maillefer, Ballaigues, Switzerland), and the CanalBrush (Coltene Whaledent, Langenau, Germany) methods for the removal of the smear layer from the apical third of root canals. METHODS Fifty distal root canals from extracted human mandibular first molars were instrumented up to ProTaper Universal F5 and divided randomly into 5 groups (n = 10) according to the following final irrigation agitation techniques: no agitation (control), ProTaper Universal file, ultrasound, CanalBrush, and Nd:YAG laser. Specimens were observed under a scanning electron microscope. The presence of the smear layer was evaluated using a 3-grade scoring system. The data were analyzed with Cohen kappa, Kruskal-Wallis, and Mann-Whitney U tests. A level of significance of .05 was adopted. RESULTS The ultrasound group performed significantly better than the rest of the groups; 56.6% of the specimens revealed no smear layer, 44.4% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In the Nd:YAG laser group, 30% of the specimens presented with no smear layer, 70% showed the presence of a moderate smear layer, and no heavy smear layers were observed. In contrast, a heavy smear layer was observed on the surfaces of the root canals in the CanalBrush (23.4%), ProTaper Universal (13.4%), and control (86.6%) groups. Statistically significant differences were observed (P < .05). CONCLUSIONS None of the agitation methods completely removed the smear layer. However, the ultrasound method performed significantly better followed by the Nd:YAG laser, the CanalBrush, and the ProTaper Universal system. Agitation of the irrigant improved smear layer removal in the apical third of the canal.

Assessment of canal walls after biomechanical preparation of root canals instrumented with protaper universalTM rotary system

Objective: The aim of this study was to examine the instrumented walls of root canals prepared with the ProTaper Universal™ rotary system. Material and Methods: Twenty mesiobuccal canals of human first mandibular molars were divided into 2 groups of 10 specimens each and embedded in a muffle system. The root canals were transversely sectioned 3 mm short of the apex before preparation and remounted in their molds. All root canals were prepared with ProTaper Universal™ rotary system or with Nitiflex™ files. The pre and postoperative images of the apical thirds viewed with a stereoscopic magnifier (×45) were captured digitally for further analysis. Data were analyzed statistically by Fishers exact test and Chi-square test at 5% significance level. Results: The differences observed between the instrumented and the noninstrumented walls were not statistically significant (p<0.05). Conclusions: The Nitiflex™ files and the ProTaper Universal™ rotary system failed to instrument all the root canal walls.

Radiological evaluation of the morphological changes of root canals shaped with ProTaper™ for hand use and the ProTaper™ and RaCe™ rotary instruments

This study evaluated, by means of the radiography examination, the occurrence of deviations in the apical third of root canals shaped with hand and rotary instruments. Sixty mandibular human molars were divided into three groups. The root canals in group 1 were instrumented with ProTaper (Dentsply/Maillefer, Ballaigues, Switzerland) for hand use, group 2 with ProTaper and group 3 with RaCe. The images obtained by double superimposition of the pre- and postoperative radiographs were evaluated by two endodontists with the aid of a magnifier-viewer and a fivefold magnifier. Statistical analysis was performed using the Fisher-Freeman-Halton. The instrumentation using the ProTaper for hand use showed 25% of the canals with a deviation in the apical third, as did the ProTaper, while the corresponding figure for the RaCe (FKG Dentaire, La-Chaux-de-Fonds, Switzerland) was 20%, but these results were not statistically significant. There was no correlation between the occurrence of deviations in the apical third and the systems used.

Evaluation of the root dentine cutting effectiveness of the HERO 642®, HERO Apical® and HERO Shaper® Rotary Systems

Different HERO rotary systems were evaluated by pre- and postoperative images of a cross-section of their mesiobuccal root thirds with a stereoscopic magnifier (45x). Fifty mesiobuccal canals of human mandibular first molars were divided into five groups: 1--HERO 642; 2--HERO 642 and HERO Apical; 3--HERO Shaper; 4--HERO Shaper and HERO Apical; 5--NitiFlex files. The perimeter of the canal was calculated using Image Tool software (UTHSCA). Final, post-instrumentation perimeters were compared by Kruskal-Wallis test (P = 0.05). The distribution of the values of the final canal perimeter for each instrumentation method was not statistically significant in any of the thirds (P = 0.174, cervical third; P = 0.874, middle third; and P = 0.631, apical third). An increase in canal perimeter was observed in all groups. In the cervical third the greatest increase was Group 5; in the middle third, Group 4, and in the apical third, Group 2.

The efficacy of photodynamic therapy and sodium hypochlorite in root canal disinfection by a single-file instrumentation technique

AIM The aim of this in vitro study was to evaluate the efficacy of photodynamic therapy (PDT) and sodium hypochlorite (NaOCl) in root canal disinfection by a single-file instrumentation technique. MATERIAL AND METHODS Seventy human single-rooted mandibular premolars were infected with Enterococcus faecalis, Pseudomonas aeruginosa, Staphylococcus aureus and Candida albicans, and divided into seven groups (n=10) according to the protocol of disinfection used. Group 1: 1% NaOCl; Group 2: 5.25% NaOCl; Group 3: saline+PDT; Group 4: 1% NaOCl+PDT; Group 5: 5.25% NaOCl+PDT; Group 6: positive control; Group 7: negative control. For PDT, methylene blue (15μg/mL) remained in the root canal for 2min, followed by irradiation with diode laser. Samples were collected before and after instrumentation and plated in specific media cultures, to assess the presence or absence of microbial growth and determine the average reduction of viable microorganisms. RESULTS 5.25% NaOCl+PDT resulted in the highest number of specimens with no microbial growth. Also, 1% NaOCl and 1% NaOCl+PDT exhibited similar antimicrobial effects. Saline+PDT was not able to eliminate all microorganisms. There was statistical significant differences between the groups and the microorganisms. CONCLUSION The association of 5.25% NaOCl with PDT was the most effective treatment against microorganisms from endodontic infection in root canals instrumented by a single-file instrumentation technique. This result shows that PDT can be useful to improve the root canal disinfection.

Soluções Irrigadoras Utilizadas para o Preparo Biomecânico de Canais Radiculares

Resumen pt: Introducao: Os microrganismos desempenham um importante papel na etiologia e manutencao das infeccoes endodonticas. Esta populacao microbiana devera ser ...

Micro–computed Tomographic Analysis of Apical Microcracks before and after Root Canal Preparation by Hand, Rotary, and Reciprocating Instruments at Different Working Lengths

Introduction: This study aimed to compare apical microcrack formation after root canal shaping by hand, rotary, and reciprocating files at different working lengths using micro–computed tomographic analysis. Methods: Sixty mandibular incisors were randomly divided into 6 experimental groups (n = 10) according to the systems and working lengths used for the root canal preparation: ProTaper Universal for Hand Use (Dentsply Maillefer, Ballaigues, Switzerland), HyFlex CM (Coltene‐Whaledent, Allstetten, Switzerland), and Reciproc (VDW, Munich, Germany) files working at the apical foramen (AF) and 1 mm short of the AF (AF − 1 mm). The teeth were imaged with micro–computed tomographic scanning at an isotropic resolution of 14 &mgr;m before and after root canal preparation, and the cross‐sectional images generated were assessed to detect microcracks in the apical portion of the roots. Results: Overall, 17 (28.3%) specimens presented microcracks before instrumentation. Apical microcracks were present in 1 (ProTaper Universal for Hand Use), 3 (Hyflex CM), and 2 (Reciproc) specimens when the instrumentation terminated at the AF. When instrumentation was terminated at AF − 1 mm, apical microcracks were detected in 3 (ProTaper Universal for Hand Use) and 4 (Hyflex CM and Reciproc) specimens. All these microcracks detected after root canal preparation were already present before instrumentation, and no new apical microcrack was visualized. For all groups, the number of slices presenting microcracks after root canal preparation was the same as before canal preparation. Conclusions: Root canal shaping with ProTaper Universal for Hand Use, HyFlex CM, and Reciproc systems, regardless of the working length, did not produce apical microcracks. HighlightsRoot sectioning studies have inconsistent reports on the impact on root dentin induced by instrumentation with hand, rotary, and reciprocating files.Micro–computed tomographic imaging was used to compare apical microcrack formation after root canal preparation with ProTaper Universal for Hand Use, HyFlex CM, and Reciproc systems working short or at the apical foramen.Neither the root canal preparation techniques nor the instrumentation lengths tested influenced the production of apical microcracks.

Comparison of the centring ability of the ProTaper™ and ProTaper Universal™ rotary systems for preparing curved root canals.

The aim of this in vitro study was to compare the centring ability of the ProTaper™ and ProTaper Universal™ rotary systems for preparing curved root canals, by means of preoperative and postoperative imaging of a cross-section of their coronal, middle and apical thirds. Twenty mesiobuccal root canals of human mandibular first molars with a degree of curvature ranging from 55° to 60° were randomly divided into two groups of 10 specimens each: Group 1, ProTaper™ rotary system; and Group 2, ProTaper Universal™ rotary system. The data were analysed statistically by Kruskal-Wallis and Students t-test at the 5% significance level. The results showed that the differences between the percentages of the presence of deviation observed were not statistically significant. Both systems showed the capacity for producing centred preparations in curved root canals with low proportions of deviation.