Cyclic Fatigue Resistance of Heat-Treated Nickel-Titanium Instruments

Introduction: This study compared the cyclic fatigue resistance (CFR) of new instruments manufactured by heat-treated nickel-titanium wire. Methods and Materials: Ninety-six new instruments from HyFlex CM (HF), Edge File (EF), Pro Design S (PDS/L) and Mtwo (MT) (20/0.06 and 25/0.06) (n=12) systems were evaluated. A stainless steel device was used and time and number of cycles to fracture (NCF) were observed. Fragments were measured and fracture surface was evaluated using scanning electron microscope (SEM). ANOVA and Tukey’s tests were applied with the level of significance set at 0.05. Results: PDS 20/0.06 and PDL 25/0.06 instruments presented the highest CFR. MT 20/0.06 and MT 25/0.06 showed the lowest CFR (P<0.05). The length of fragments was similar for 25/0.06 instruments and HF presented the highest one for 20/0.06 instruments. SEM analyses showed morphology suggestive of ductile fracture. Conclusion: Heat treatment increased resistance to cyclic fatigue differently for each type of instrument. PDS 20/0.06 and PDL 25/0.06 present higher cyclic fatigue resistance.Keywords: Cyclic Fatigue; Instrumentation; Nickel-Titanium; Rotary Syste

Evaluation of physicochemical properties of root-end filling materials using conventional and Micro-CT tests

Objective To evaluate solubility, dimensional stability, filling ability and volumetric change of root-end filling materials using conventional tests and new Micro-CT-based methods. Material and Methods 7 Results The results suggested correlated or complementary data between the proposed tests. At 7 days, BIO showed higher solubility and at 30 days, showed higher volumetric change in comparison with MTA (p;0.05) at 7 days. At 30 days, they presented similar solubility. BIO and MTA showed higher dimensional stability than ZOE (

Solubility and bacterial sealing ability of MTA and root-end filling materials

Objective To evaluate solubility and sealing ability of Mineral Trioxide Aggregate (MTA) and root-end filling materials. Material and Methods The materials evaluated were: MTA, Calcium Silicate Cement with zirconium oxide (CSC/ZrO2), and zinc oxide/eugenol (ZOE). Solubility test was performed according to ANSI/ADA. The difference between initial and final mass of the materials was analyzed after immersion in distilled water for 7 and 30 days. Retrograde cavities in human teeth with single straight root canal were performed by using ultrasonic tip CVD 9.5107-8. The cavities were filled with the evaluated materials to evaluate sealing ability using the bacterial leakage test with Enterococcus faecalis. Bacterial leakage was evaluated every 24 hours for six weeks observing the turbidity of Brain Heart infusion (BHI) medium in contact with root apex. Data were submitted to ANOVA followed by Tukey tests (solubility), and Kruskal-Wallis and Dunn tests (sealing ability) at a 5% significance level. Results For the 7-day period, ZOE presented highest solubility when compared with the other groups (

Solubility, porosity, dimensional and volumetric change of endodontic sealers

Made available in DSpace on 2019-10-06T15:51:21Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-07-01. Added 1 bitstream(s) on 2019-10-09T18:34:58Z : No. of bitstreams: 1 S0103-64402019000400368.pdf: 231317 bytes, checksum: 55f93b71e9cc966f98ddf8025bcd31c8 (MD5)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)The aim Of this study was to evaluate physical properties Of endodontic sealers (AH Plus, MTA Fillapex and Endofill), by conventional and micro-CT tests. Dimensional stability was evaluated after immersion Of materials in distilled water for 30 days. Solubility and volumetric change were evaluated after 7 and 30 days Of immersion in distilled water. Solubility was evaluated by means Of mass loss and volumetric change was assessed by micro-CT. Porosity was evaluated under a microscope after 7 days Of immersion in distilled water, and by using micro-CT after setting and immersion in distilled water for 7 and 30 days. Statistical analysis was performed by ANOVA and Tukey’s test with 5% significance level. MTA Fillapex presented the highest solubility (p0,05). In conclusion, MTA Fillapex presented higher solubility, dimensional and volumetric change besides porosity compared to the Other evaluated sealers. The assessed physical properties of sealers are related, and the different tests provided complementary data. Micro-CT is a valuable method for assessment Of physical properties Of endodontic materials.Department of Restorative Dentistry School of Dentistry UNESP – Universidade Estadual PaulistaDepartment of Dentistry School of Dentistry UFBA – Universidade Federal da BahiaSchool of Dentistry Institute of Clinical Sciences College of Clinical and Medical Sciences University of Birmingham, EdgbastonDepartment of Restorative Dentistry School of Dentistry UNESP – Universidade Estadual PaulistaCAPES: 2014/16510-0FAPESP: 2014/16510-0CAPES: 2015/03437-6FAPESP: 2015/03437-6CAPES: 2016/00321-0FAPESP: 2016/00321-0CAPES: 2017/19049-0FAPESP: 2017/19049-

Atividade antimicrobiana residual de pastas à base de hidróxido de cálcio e associações como medicação intracanal

A resistência do biofilme endodôntico pode requerer um período maior de permanência da medicação intracanal a fim de prolongar sua ação antimicrobiana. O objetivo deste estudo foi avaliar a ação antimicrobiana residual das medicações intracanal: G1) hidróxido de cálcio + soro; G2) Calen; G3) Calen + PMCC; G4) Calen + clorexidina 0,4% e G5) clorexidina gel 2% frente à Enterococcus faecalis, Candida albicans, Pseudomonas aeruginosa, Staphylococcus aureus e Kocuria rhizophila em 60 canais radiculares bovinos. Os canais radiculares foram instrumentados e preenchidos com as medicações intracanal, as quais foram removidas após os períodos experimentais (15, 30, 60 e 90 dias) e empregadas na técnica de difusão em ágar. Os halos de inibição foram evidenciados por gel de TTC e então mensurados. Os dados de halos de inibição foram submetidos à análise estatística dos testes Kruskall-Wallis e Dunn, com nível de significância de 5%. O Ca(OH)2 + soro apresentou efeito até o período de 15 dias. A pasta Calen demonstrou efeito residual aos 60 dias frente ao S. aureus, enquanto Calen/PMCC até o período de 90 dias frente à S. aureus e K. rhizophila e aos 30 dias para E. faecalis. A pasta Calen associado à clorexidina foi efetiva frente à E. faecalis até o período de 60 dias. A clorexidina gel 2% apresentou ação residual em todos os períodos, com exceção de E. faecalis aos 90 dias, também apresentou atividade antimicrobiana mais prolongada, seguido das associações do hidróxido de cálcio com clorexidina e PMCC

Evaluation of physicochemical properties of root-end filling materials using conventional and Micro-CT tests

Abstract Objective To evaluate solubility, dimensional stability, filling ability and volumetric change of root-end filling materials using conventional tests and new Micro-CT-based methods. Material and Methods Solubility (loss of mass) after 7 and 30 days, and dimensional stability (in mm) were evaluated in accordance with Carvalho-Junior, et al. 7 (2007). The filling ability and volumetric change (in mm3) were evaluated by Micro-CT (Bruker-MicroCT, Kontich, Belgium) using resin models with cavities 3 mm deep and 1 mm in diameter. The cavities were filled with materials to evaluate filling ability, and then scanned by Micro-CT. After 7 and 30 days immersed in distilled water, the filled cavities were scanned again to evaluate the volumetric change. MTA Angelus (MTA), Biodentine (BIO) and zinc oxide-eugenol cement (ZOE) were evaluated. Data were submitted to analysis of variance (ANOVA) and Tukey's test with 5% significance level. Results The results suggested correlated or complementary data between the proposed tests. At 7 days, BIO showed higher solubility and at 30 days, showed higher volumetric change in comparison with MTA (p0.05) at 7 days. At 30 days, they presented similar solubility. BIO and MTA showed higher dimensional stability than ZOE (p<0.05). ZOE and BIO showed higher filling ability (p<0.05). Conclusions ZOE presented a higher dimensional change, and BIO had greater solubility after 7 days. BIO presented filling ability and dimensional stability, but greater volumetric change than MTA after 30 days. Micro-CT can provide important data on the physicochemical properties of materials complementing conventional tests

Micro-CT analysis of filling ability and porosity of root-end filling materials

<div><p>Abstract Introduction Filling ability of retrograde cavity and porosity are important properties for root-end filling materials and may be evaluated by using microcomputed tomography (micro-CT). Objective To evaluate filling ability and porosity of root-end filling materials using microcomputed tomography (micro-CT). Material and method Cavities with 1 mm internal diameter and 3 mm depth were prepared in bovine dentin sections by using ultrasonic tips (CVD No. 6.1107-6), and filled by Mineral Trioxide Aggregate (MTA); Sealer 26 (S26) and zinc oxide and eugenol cement (ZOE). Before and after filling, cavities were scanned by using micro-CT (SkyScan 1176). Filling and porosity were analyzed by using CTAn software. Filling ability was calculated based on volumetric percentage of the filled cavity. The number and percentage of closed pores were measured throughout entire extension of the filled cavity (total) and in each third (cervical, middle and apical), by using bi and tridimensional analyses. The filling data were submitted to ANOVA and Tukey statistical tests, and porosity data to Kruskall-Wallis and Dunn tests, at a 5% significance level. Result S26 and ZOE presented higher filling ability than MTA (p<0.05). S26 showed the highest total porosity (number and percentage) (p<0.05). In all thirds after 2D and 3D analyses, porosity was higher for S26 in comparison to MTA and ZOE (p<0.05). Conclusion Although Sealer 26 presented more porosity, the material was associated with a great filling ability. Micro-CT analysis showed no correlation between filling ability and porosity.</p></div

Solubility and bacterial sealing ability of MTA and root-end filling materials

ABSTRACT Objective To evaluate solubility and sealing ability of Mineral Trioxide Aggregate (MTA) and root-end filling materials. Material and Methods The materials evaluated were: MTA, Calcium Silicate Cement with zirconium oxide (CSC/ZrO2), and zinc oxide/eugenol (ZOE). Solubility test was performed according to ANSI/ADA. The difference between initial and final mass of the materials was analyzed after immersion in distilled water for 7 and 30 days. Retrograde cavities in human teeth with single straight root canal were performed by using ultrasonic tip CVD 9.5107-8. The cavities were filled with the evaluated materials to evaluate sealing ability using the bacterial leakage test with Enterococcus faecalis. Bacterial leakage was evaluated every 24 hours for six weeks observing the turbidity of Brain Heart infusion (BHI) medium in contact with root apex. Data were submitted to ANOVA followed by Tukey tests (solubility), and Kruskal-Wallis and Dunn tests (sealing ability) at a 5% significance level. Results For the 7-day period, ZOE presented highest solubility when compared with the other groups (p<0.05). For the 30-day period, no difference was observed among the materials. Lower bacterial leakage was observed for MTA and CSC/ZrO2, and both presented better results than ZOE (p<0.05). Conclusion MTA and CSC/ZrO2 presented better bacterial sealing capacity, which may be related to lower initial solubility observed for these materials in relation to ZOE