Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometre

Introduction: Manufacturers offer gutta-percha (GP) cones matched with different sizes of endodontic files as an attempt to simplify the obturation process and create a tight seal in the canal. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different levels using laser micrometre. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R40 (40/0.06) (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo 40/0.06 (VDW, Munich, Germany) were examined using laser micrometre (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. The data was analysed using the independent t-test. The differences were considered at 0.05. Results: The diameter of GP master cones was significantly larger than that of the corresponding files at all levels in all brands. ProTaper GP diameter was closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, File=0.49). Conclusion: Within the same manufacturer, GP cone diameters do not match the diameters of their corresponding files. Clinicians are advised to use a GP gauge to cut the tip so as to appropriate the diameter from a smaller sized GP cone.Keywords: Diameter; Gutta-Percha; Root Canal; Rotary File; Size 

The Intra-Manufacture Diameter Variability of Rotary Files and Their Corresponding Gutta-Percha Cones Using Laser Scan Micrometer

Introduction: As an attempt to simplify the obturation process and create a tight seal, manufacturers offer gutta-percha (GP) cones matching different sizes of endodontic files. The purpose of this study was to evaluate whether intra-manufacture GP diameters matched the diameters of their corresponding files at different horizontal levels of the canal. Methods and Materials: Twenty files and corresponding GP master cones of Reciproc R 40/0.08 (VDW, Munich, Germany), WaveOne Large (40/0.08) (Dentsply Maillefer, Ballaigues, Switzerland), ProTaper F3 (30/0.09) (Dentsply Maillefer, Ballaigues, Switzerland), and Mtwo (40/0.06) (VDW, Munich, Germany) were examined using laser micrometer (LSM 6000 by Mitutoyo, Japan) with accuracy of 1 nm to establish their actual diameter at D0, D1, D3 and D6. Data were analysed using the independent t-test. The differences were considered as significant for P<0.05. Results: The diameter of GP master cones was significantly larger than the corresponding files at all levels with all the above brands. ProTaper GP diameter were closest to the file diameter at D1 (GP=0.35, File=0.35 mm), and D3 (GP=0.48, file=0.49). Conclusion: This in vitro study showed that within the same manufacturer GP cone diameters do not match the diameters of their corresponding files.Keywords: Diameter; Gutta-percha Cone; Laser Scan Micrometer; Rotary File; Tape

Reduction of dual‐species biofilm after sonic‐ or ultrasonic‐activated irrigation protocols: A laboratory study

Aim: To evaluate the antibacterial effect of sonic- and ultrasonic-activated irrigation on bacterial reduction of a dual-species biofilm in root canals compared to nonactivated irrigation in a laboratory study. Methodology: Two hundred and forty extracted human single-rooted maxillary anterior teeth were divided into two main groups (G, n = 120) according to the initial preparation size of the root canal (G1: size 25, 0.06 taper, G2: size 40, 0.06 taper). Root canals were inoculated with Enterococcus faecalis and Streptococcus oralis. After 5 days, G1 received combined instrumentation (up to size 40, 0.06 taper) and irrigation/activation, whereas G2 received solely irrigation/activation protocols. In both groups, irrigation was performed with sodium hypochlorite (NaOCl 1%) or physiological saline (NaCl 0.9%), using nonactivated syringe irrigation, sonic activation (2 x 30 s) or ultrasonic activation (2 x 30 s). Logarithmic reduction factors (LRFs) of colony-forming units were analysed separately for dentine-adherent and planktonic bacteria immediately after irrigation/activation protocols (time-point 1) or after 5 days of further incubation (time-point 2) by analysis of variance (anova) and post hoc tests (Tukey's HSD, t-test). The significance level was set at 0.05. Results: In G1 subgroups (combined instrumentation with irrigation/activation), LRFs were significantly affected by the applied irrigation solution (p .05; anova). In G2 subgroups (solely irrigation/activation), both, irrigant solution and activation, significantly affected LRFs (p < .0001, anova). Sonic activation resulted in significantly higher LRFs than ultrasonic activation (p < .0001) which had significantly greater reductions than nonactivated irrigation (p < .05; Tukey's HSD). At T2, strong bacterial regrowth was observed in all groups; however, a significant bacterial reduction was detected for factors instrumentation, irrigant solution and activation (p < .0001; anova). Similar LRFs were found for dentine-adherent and planktonic bacterial cells in all groups (r = 0.91 at T1, r = 0.8 at T2). Conclusions: In this laboratory study on extracted maxillary anterior teeth high-frequency sonic activation resulted in a greater bacterial reduction compared to ultrasonic activation in groups receiving solely irrigation/activation protocols; however, irrigation using NaOCl and ultrasonic activation also contributed significantly to bacterial reduction compared to the control groups

Gaps at the interface between dentine and self‐adhesive resin cement in post‐endodontic restorations quantified in 3D by phase contrast‐enhanced micro‐CT

Aim: To assess the extent of gaps between root dentine and titanium or fibreglass post restorations following cementation with a self-adhesive resin cement. Methodology: Fourteen root filled maxillary central incisors restored with prefabricated posts made of Fibreglass (n = 7) or Titanium (n = 7) and cemented with RelyX Unicem 2 were imaged by rapid, high-resolution phase contrast-enhanced micro-CT (PCE-CT) in a synchrotron X-ray imaging facility (ID19, ESRF, 34 KeV, 0.65 µm pixel resolution). Reconstructions were used to measure canal, cement and post perimeters and cross-sectional areas and interfacial gaps at 0.1 mm increments in the root canal space, along the cervical region of the tooth. Remnants of endodontic sealer (AH Plus), when present, were also quantified. Mann–Whitney and 2-way ANOVA tests were used to compare findings within slices and between the two post groups. Pearson correlation coefficients (r) were determined between the interfacial gaps and the other measured parameters. Results: Clearly detectable gaps were found in 45% (±14%) of the interfaces between dentine and cement, along the canal in the cervical area of the tooth beneath the core. The length of interfacial gaps was moderately correlated to the canal cross-sectional area, to the canal perimeter and to the canal area filled by cement (R = 0.52 ~ 0.55, P 0.01). Both post types had defect-free interfaces with cement. Endodontic sealer remnants were found on ~10% of the canal walls and were moderately correlated to the presence of gaps. Approximately 30% of the sealer-affected interfaces exhibited no detachment between dentine, sealer and cement. Conclusions: Self-adhesive cements had interfacial gaps along substantial regions of the root canal surface, which was not correlated with the amount of cement in the canal. PCE-CT proved to be an excellent non-destructive method to study root canal restorations of hydrated samples in 3D

Porosity distribution in single cone root canal fillings performed by operators with different clinical experience: a microCT assessment /

The objective of this study was to assess the porosity distribution of BioRoot RCS/singlegutta-percha point root-canal fillings performed by a general dental practitioner and endodontist.Fourteen plastic models of maxillary premolars with two roots were selected and shaped with HyFlexEDM instruments to a size 40/0.04 taper and randomly divided into two experimental groups. Atotal of 14 canals in each group were obturated by two different operators with one HyFlex EDM size40 gutta-percha point and BioRoot RCS sealer. The specimens were scanned with a high-resolutionmicro-computed tomography scanner, and the porosity of the fillings at the coronal, middle, andapical thirds of the root canals was qualified and quantified. The differences between groups androot-canal thirds were compared using Mann–Whitney, Friedman, and Wilcoxon tests with thesignificance level set atp 0.05). Statistically significant differenceswere determined only in the coronal third (p 0.05)

The effect of root dentin conditioning protocols on the push-out bond strength of three calcium silicate sealers

© 2015 Elsevier Ltd. All rights reserved.Objectives: To compare the effects of irrigation protocols on the push-out bond strength of calcium silicate materials at two different time periods (7-days and 3-months). Materials and methods: Root canals (n=300) were irrigated with one of the following (n=60): group 1 (3% NaOCl-17% EDTA); group 2 (17% EDTA-3% NaOCl); group 3 (1:1 mixture of 6% NaOCl and 18% etidronic acid); group 4 (3% NaOCl-QMix 2in1); group 5 (3% NaOCl-2% chlorhexidine). Specimens were subdivided into three subgroups (n=20): A, Endosequence BC sealer [EBC]; B, MTA Plus [MTA-P]; C, Tech Biosealer Endo [TECH]. Specimens were suspended in phosphate buffered saline [PBS] for 7 days or 3 months (n=10 per sealer). Push-out bond strength was measured and data were analyzed (P=0.05). Results: MTA-P: showed the highest bond strength at both time periods, when NaOCl+EA was used as an irrigant. This was not significantly different from the strength produced when NaOCl-QMix was used for 7 days (P>0.05). There was no significant difference between the bond strengths of the three materials when irrigated with group 1, 2 or 5 (P>0.05), but these groups showed significantly lower bond strengths than groups 3 and 4 (P<0.05). While the bond strength of EBC and MTA-P in specimens irrigated with groups 3 and 4 improved significantly with time [P<0.05], this was not true for TECH. Conclusions: Push-out bond strength of calcium silicate cements was differentially influenced by irrigation protocol and time. MTA Plus showed the highest bond strength at both time periods, when root canals were irrigated with NaOCl+EA. The bond strength of Tech Biosealer Endo did not improve with time immaterial of the irrigation protocols.Link_to_subscribed_fulltex

Influence of Irrigation Sequence on the Adhesion of Root Canal Sealers to Dentin: A Fourier Transform Infrared Spectroscopy and Push-out Bond Strength Analysis

© 2015 American Association of Endodontists.Introduction There is a lack of evidence on the chemical interaction between sealers and dentin. The influence of irrigation on the chemical interaction between root canal sealers and dentin was analyzed by using Fourier transform infrared spectroscopy (FTIRS) and measurement of dislocation resistance. Methods Single-rooted teeth (n = 120) were instrumented with 3% NaOCl as the irrigant and divided into 4 groups (n = 30) on the basis of irrigation protocol: group 1, 3% NaOCl, 17% EDTA, water; group 2, 17% EDTA, 3% NaOCl, water; group 3, 3% NaOCl, QMix, water; group 4, 3% NaOCl, water. Each group was divided into 3 subgroups (n = 10) on the basis of the root canal sealer: A, epoxy resin (AH Plus); B, silicone (RoekoSeal); C, calcium hydroxide (Sealapex). The dislocation resistance was assessed by using push-out bond strength test. The data were statistically analyzed by three-way analysis of variance and Holm-Sidak tests (P =.05). Dentin powder treated as per the conditioning protocols mentioned was mixed with the sealers and analyzed by FTIRS. Results A significant interaction was observed between irrigation protocol, type of sealer, and root segment (P .05). AH Plus showed the highest bond strength (P <.05). FTIRS showed chemical bonding between AH Plus and dentinal collagen. In groups 2 and 4, no chemical bonding was observed. Conclusions Bond strength of sealers is differentially affected by the irrigation protocol. The epoxy resin sealer AH Plus chemically bonds to dentinal collagen. This interaction is influenced by the irrigation protocols.Link_to_subscribed_fulltex

Porosity Distribution in Apically Perforated Curved Root Canals Filled with Two Different Calcium Silicate Based Materials and Techniques: A Micro-Computed Tomography Study

The present study evaluated the porosity distribution of BioRoot RCS/single gutta-percha point (BR/SC) and MTA flow (MF) fillings, which were used as plugs for the apical perforation repair in curved canals of extracted mandibular molars using micro-computed tomography (&#956;CT). Forty mesial root canals of mandibular first molars were shaped with ProTaper NEXT X1&#8722;X5 files 2 mm beyond the apex to simulate apical perforations that were randomly divided into two groups (n = 20) according to the material and technique used for the apical plug: BR/SC or MF. The specimens were scanned before and after canal filling at an isotropic resolution of 9.9 &#956;m. The volumetric analysis of voids in the apical 5 mm of the fillings was performed. Data were analyzed using one-way ANOVA with Bonferroni correction (p &lt; 0.05). Micro-computed tomography (&#181;CT) evaluation revealed significant differences between the groups in terms of porosity: the total volume and percentage volume of voids was lower in the BR/SC group in comparison with the MF group (p &lt; 0.05), with the predominance of open pores in both groups. Neither of the materials and/or application techniques were able to produce void-free root fillings in the apical region of artificially perforated curved roots of mandibular molars

Porosity Distribution in Single Cone Root Canal Fillings Performed by Operators with Different Clinical Experience: A microCT Assessment

The objective of this study was to assess the porosity distribution of BioRoot RCS/single gutta-percha point root-canal fillings performed by a general dental practitioner and endodontist. Fourteen plastic models of maxillary premolars with two roots were selected and shaped with HyFlex EDM instruments to a size 40/0.04 taper and randomly divided into two experimental groups. A total of 14 canals in each group were obturated by two different operators with one HyFlex EDM size 40 gutta-percha point and BioRoot RCS sealer. The specimens were scanned with a high-resolution micro-computed tomography scanner, and the porosity of the fillings at the coronal, middle, and apical thirds of the root canals was qualified and quantified. The differences between groups and root-canal thirds were compared using Mann–Whitney, Friedman, and Wilcoxon tests with the significance level set at p &lt; 0.05. The highest number of pores was observed in the apical third of root-canal fillings in both groups; however, the porosity distribution between the two groups was not significantly different in the apical and middle thirds (p &gt; 0.05). Statistically significant differences were determined only in the coronal third (p &lt; 0.05). The predominance of open pores was detected in all root-canal thirds and groups, with no significant differences in the number of open pores between the coronal and middle thirds (p &gt; 0.05)