Presence Of Gutta-percha Research Articles

Do different irrigating solutions affect the dislodgement resistance of bioceramic-based root canal sealers? A systematic review and meta-analysis

This review aimed to appraise and evaluate the effect of different irrigating solutions on the dislodgement resistance of bioceramic-based sealers to root dentine walls using a push-out bond strength test. Ten electronic databases (PubMed, Google Scholar, Web of Science, ScienceDirect, Cochrane, EMBASE, EBSCO, Open Gray, Library Genesis, LILACS) and five textbooks were searched for English-language articles published between January 1970 to March 2021. Only in-vitro, in-vivo or ex-vivo articles were included and assessed using the modified OHAT Risk of Bias assessment tool. Data were analyzed using the DerSimonian-Laird random-effect model. Eleven articles were included. All studies were in-vitro experiments, and they were classified as Tier 1 based on their risk of bias assessments. Single-arm meta-analysis revealed that the highest mean pooled bond strength was noted in samples irrigated with 2.5–3% NaOCl, followed by 17% EDTA, 2% CHX, MTAD, and lastly saline. Two-arm meta-analysis showed that 17% EDTA and 2% CHX increase the bond strength of bioceramic sealers by more than 2.5–3% NaOCl, but no significant differences were noted (p > 0.05). Moreover, no significant differences (p > 0.05) were also found when comparing 17% EDTA with 2% CHX and saline, respectively. Substantial heterogeneity was observed with the overall I 2 ranging from 0% to 99.49%. Although using 2.5–3% NaOCl as irrigating solution yielded higher dislodgement resistance of bioceramic-based root canal sealers, other factors such as the type of bioceramic sealer used, presence of gutta-percha, sample thickness, and various methodological approaches significantly affected the push-out bond strength results.

Endodontic Irrigants and Their Activation Efficacy on Cleansing Post-Space Root Canal Walls

The aim of this study was to evaluate the efficacy of activated irrigants (EDTA e NaOCL) during the cleansing of root walls, of the smear layer, of the debris, and gutta-percha after the preparation of the restorative space. Twenty single and multi-rooted (n = 20) have been collected. All samples were prepared by the same operator, using Nickel-titanium rotating instruments (Mtwo) through the Simultaneous Shaping Technique. The continuous-wave of condensation technique of obturation was used. To all specimens, the restorative space has been made, leaving 5 mm of apical gutta-percha, and postoperative periapical X-rays were performed. The samples were randomly divided into two groups: Group (A): cleansing of the root walls with ultrasonic activation of the irrigants (NEWTRON P5 XS; Satelec Acteon); Group (B): radicular walls wash without ultrasonic activation of endodontic irrigants (NaOCl 5.25% and EDTA 17%). Both dental sample groups were cut longitudinally with a low-speed saw (Isomet); the samples were observed by using a scanning electron microscope (Jeol, Jsm-6060LV) in order to evaluate: (1) the amount of debris/smear layer; (2) the mount of obstruction of dentinal tubules found in the two groups; and (3) evaluation of the presence of gutta-percha. Then, the other five samples each group (with and without ultrasonic activation) were prepared following the same protocol. Then, a universal bonding system (G-Praemio Bond, GC) and a layer of a flowable resin composite (Gaenial Flow, GC) were light-cured and used on top of the prepared root canal walls. The samples were cut in two pieces along the long axis of the root. Then, half sample teeth were kept in an acidic solution (37% HCl) for 48 h in order to completely dissolve dental structures and to have a direct view of resin tags formation under SEM. The other half was prepared to observe the adhesive interface under SEM. The amount of debris was not satisfactory in 9 out of 10 cases in Group B, while in Group A, which has been treated with ultrasounds, the result was either good or great in most of the samples. For the sample group treated with ultrasound, the tubules were evaluated as perfectly clean in 9 out of 10 cases, instead, the results are unsatisfactory for 9 out of 10 cases of group B not treated with ultrasound. Differences between Group A and B were statistically significant. With respect to the presence of debris and tubules obstruction treatment with ultrasonic activation, it offers with no doubt better results. When ultrasonic activation is used in combination with endodontic irrigants, a clean dentin substrate is be obtained for the adhesion of restorative materials, but in order to confirm the findings of this study, further in vivo trials are needed.

Kinetics of the thermal decomposition of Eucommia ulmoides Oliver leaves and its fermentation products

ABSTRACTThe pyrolysis characteristics of Eucommia ulmoides Oliver leaves untreated and treated by biological fermentation were investigated using thermogravimetric analysis. The derivative thermogravimetry curves, kinetic characteristics, and activation energy of the samples were significantly different from other biomass. The average activation energies (253.40 and 268.77 kJ/mol, 257.71, and 270.82 kJ/mol) were close almost similar to that obtained from Kissinger–Akahira–Sunose and Flynn–Wall–Ozawa methods and were higher due to the presence of gutta-percha. Meanwhile, the decomposition and kinetic characteristics could be changed by fermentation technology. Besides, Coats–Redfern revealed that second-order model (f(α) = (1–α)2) could be used to better describe the decomposition mechanism of these samples.

Influence of Tooth Orientation on the Detection of Vertical Root Fracture in Cone-beam Computed Tomography

IntroductionThe purpose of this study was to assess the influence of tooth orientation in relation to the projection plane of the x-rays on the detection of vertical root fracture (VRF) with different filling materials using cone-beam computed tomographic (CBCT) imaging. MethodsThirty single-rooted human teeth were endodontically instrumented, and VRF was induced in half of the sample. The roots were individually placed in the dental socket of a phantom head composed of a dry human skull and mandible, and CBCT images were obtained of each root with the longitudinal axis in 2 orientations: perpendicular and parallel to the projection plane of the x-rays. Also, each root was scanned under 3 filling conditions: without filling material, with gutta-percha, and with a metal post. Radiation doses at specific anatomic regions of the phantom were obtained for the 2 orientations. Five radiologists evaluated all images and rated the fractures on a 5-point scale. The sensitivity, specificity, accuracy, and positive and negative predictive values were calculated. The area under the receiver operating characteristic curve and the dosimetric outcomes for each root orientation and filling material were compared, respectively, with 2-way and 1-way analysis of variance with the post hoc Tukey test (α = 0.05). ResultsThere was no significant difference (P ≥ .05) in the detection of VRF between root orientations regardless of the filling material. Az values were significantly lower (P < .05) in the presence of gutta-percha and a metal post. The root orientation varied the absorbed dose at some anatomic regions. ConclusionsThe orientation of the tooth in relation to the projection plane of the x-rays does not influence the detection of VRF using CBCT imaging irrespective of the intracanal material.

The Performance of a Zirconium-based Root Filling Material with Artifact Reduction Properties in the Detection of Artificially Induced Root Fractures Using Cone-beam Computed Tomographic Imaging

IntroductionLimited field of view cone-beam computed tomographic (CBCT) imaging has been used to augment clinical testing of vertical root fractures (VRFs); however, the presence of gutta-percha (GP) in the canal space generates substantial imaging artifacts that make fracture detection difficult. The purpose of this study was to evaluate the influence of a zirconium (Zr)-based root filling material with radiologic properties that reduce beam hardening (BH) artifacts using CBCT imaging in the in vitro diagnosis of VRFs. MethodsOne hundred seventy-six single-rooted mandibular premolar teeth were obtained, and half of these teeth were filled with GP or Zr (CPoint; EndoTechnologies, LLC, Shrewsbury, MA). VRFs were induced in 44 decoronated teeth in each group using an Instron (Norwood, MA) Universal Testing Machine. Each root was then placed in a dry human mandible and imaged with the Carestream 9000 3D CBCT system (Carestream Dental, Atlanta, GA). The images were evaluated by 6 oral maxillofacial radiologists (OMRs) and residents. ResultsThe sensitivity was greater for detecting VRFs in the Zr group than the GP group (P = .035). However, the specificity was greater for the GP group than the Zr group (P = .028). Receiver operating characteristic area under the curve values were greater for the Zr group than the GP group, but these differences were not statistically significant. The OMRs outperformed the residents in the detection of VRFs in the Zr group with respect to specificity (P = .006) and positive predictive value (P = .012). ConclusionsThe reduced BH of the Zr group improved the sensitivity of the detection of artificially induced VRFs. The ability to detect VRFs in the Zr group was further enhanced by clinical experience.

Optimization of Tube Current in Cone-beam Computed Tomography for the Detection of Vertical Root Fractures with Different Intracanal Materials

IntroductionThere is no consensus about the accuracy of cone-beam computed tomography (CBCT) for detecting vertical root fractures (VRFs), nor is there certainty about the isolated effect of different tube current parameters on the diagnosis of VRF through CBCT scans. This study aimed to evaluate how tube current affects the detection of VRF on CBCT examinations in the absence of intracanal materials and in the presence of gutta-percha (GP) and metal (MP) or fiberglass (FP) intracanal posts. MethodsThe sample consisted of 320 CBCT scans of tooth roots with and without VRF divided into 8 groups: no fracture/no intracanal material; no fracture + GP; no fracture + MP; no fracture + FP; fracture/no intracanal material; fracture + GP; fracture + MP; fracture + FP. The scans were acquired with an OP300 unit using 4 different milliamperes (4 mA, 8 mA, 10 mA, 13 mA). Five oral radiologists analyzed the images. The area under the receiver operating characteristic curve (Az), sensitivity, specificity, positive and negative predictive values, and interobserver agreement were calculated. ResultsDiagnostic performance for the different milliamperes tested was similar for teeth without root filling materials or with FP. Teeth with GP and MP showed the highest Az values for 8 mA and 10 mA, respectively. For teeth with MP, specificity was significantly higher when 10 mA was used. ConclusionsFor teeth without root filling materials or with FP, the use of a reduced milliampere does not seem to influence the detection of VRF in a significant manner. For teeth with GP and MP, an increased milliampere may lead to increased diagnostic performance.

Assessment of vertical root fracture using cone-beam computed tomography

PurposeThe aim of this study was to investigate the accuracy of cone-beam computed tomography (CBCT) in the diagnosis of vertical root fractures in a tooth with gutta-percha and prefabricated posts.Materials and MethodsThis study selected 96 extracted molar and premolar teeth of the mandible. These teeth were divided into six groups as follows: Groups A, B, and C consisted of teeth with vertical root fractures, and groups D, E, and F had teeth without vertical root fractures; groups A and D had teeth with gutta-percha and prefabricated posts; groups B and E had teeth with gutta-percha but without prefabricated posts, and groups C and F had teeth without gutta-percha or prefabricated posts. Then, the CBCT scans were obtained and examined by three oral and maxillofacial radiologists in order to determine the presence of vertical root fractures. The data were analyzed using IBM SPSS 20.0 (IBM Corp., Armonk, NY, USA).ResultsThe kappa coefficient was 0.875±0.049. Groups A and D showed a sensitivity of 81% and a specificity of 100%; groups E and B, a sensitivity of 94% and a specificity of 100%; and groups C and F, a sensitivity of 88% and a specificity of 100%.ConclusionThe CBCT scans revealed a high accuracy in the diagnosis of vertical root fractures; the accuracy did not decrease in the presence of gutta-percha. The presence of prefabricated posts also had little effect on the accuracy of the system, which was, of course, not statistically significant.

Influence of thermo-curing on the flexural strength of GIC

(ISO/TS11405:2003) and immersion in a 2% methylene-blue (24h). The null-hypothesis is an absence of infiltration, voids after thermocycling. After the image steromicroscope acquisition (13×), the macrostructural analysis exploited a digital automated software (Jmicrovision), in order to assess the degree of infiltration, presence of guttapercha, micro or macrovoids. The data were statistically analysed using Chisquared and t-student test (p=0.05). Results: The etching procedure improves the compositedentin bond by reducing the rate of infiltration: we observed a significant infiltration in sections until 5mm in group B (p<0.05). The presence of voidswas due only to operator errors or anatomical variables, since the self-mixing application system ensures no air bubbles within the material. Conclusion: A further etching step could be a reliable method to improve the cement-dentin adhesion in post luting.

Irradiance–distance, beam uniformity, and heat generation of seven LED lights

(ISO/TS11405:2003) and immersion in a 2% methylene-blue (24h). The null-hypothesis is an absence of infiltration, voids after thermocycling. After the image steromicroscope acquisition (13×), the macrostructural analysis exploited a digital automated software (Jmicrovision), in order to assess the degree of infiltration, presence of guttapercha, micro or macrovoids. The data were statistically analysed using Chisquared and t-student test (p=0.05). Results: The etching procedure improves the compositedentin bond by reducing the rate of infiltration: we observed a significant infiltration in sections until 5mm in group B (p<0.05). The presence of voidswas due only to operator errors or anatomical variables, since the self-mixing application system ensures no air bubbles within the material. Conclusion: A further etching step could be a reliable method to improve the cement-dentin adhesion in post luting.

Diagnostic Ability of a Cone-Beam Computed Tomography Scan to Assess Longitudinal Root Fractures in Prosthetically Treated Teeth

Introduction This study evaluated the influence of cast-gold posts on the diagnostic ability of a cone beam computed tomography (CBCT) system in assessing longitudinal root fractures. In addition, the influence of gutta-percha and variations in voxel resolution were assessed. Methods One hundred eighty endodontically prepared teeth were divided into 3 experimental and 3 control groups and placed in a dry human skull. The teeth in the experimental groups were artificially fractured. Certain experimental and control groups were filled with gutta-percha cones. Other experimental and control groups were filled with cast-gold posts. All the teeth were viewed by using a tomography scan with 2 voxel resolution protocols (0.3-mm and 0.2-mm). A calibrated examiner, blinded to the protocol, assessed the images by using the nominated scan software. Results The kappa values obtained for intraobserver reproducibility were 0.84 and 0.93 for 0.3-mm and 0.2-mm voxel resolution, respectively. The presence of gutta-percha or posts reduced the overall sensitivity and specificity in both voxel resolutions, but with no significant association. The CBCT specificity values were similar and did not depend on the voxel resolution adopted. In contrast, the sensitivity values were significantly higher for 0.2-mm voxel resolution in nonfilled ( P < .05), gutta-percha ( P < .001), and overall ( P < .001) groups. Conclusions The CBCT diagnostic ability was not influenced by the presence of posts or gutta-percha, and the 0.3-mm voxel resolution images were demonstrated not to be a reliable protocol for the investigation of longitudinal root fractures.

Accuracy of two root canal length measurement devices integrated into rotary endodontic motors when removing gutta‐percha from root‐filled teeth

To evaluate ex vivo the accuracy of the integrated electronic root canal length measurement devices within TCM Endo V and Tri Auto ZX motors whilst removing gutta-percha and sealer from filled root canals. Forty freshly extracted maxillary and mandibular incisor teeth with mature apices were selected. Following access cavity preparation, the length of the root canals were measured visually 0.5 mm short of the major foramen (TL). The canals were prepared using the HERO 642 system and then filled with gutta-percha and AH26 sealer using a lateral compaction technique. After 7 days the coronal temporary filling was removed and the roots mounted in an alginate experimental model. The roots were then randomly divided in two groups. The access cavities were filled with chloroform to soften the gutta-percha and allow its penetration using the Tri Auto ZX and the TCM Endo V devices in groups 1 and 2, respectively. The 'automatic apical reverse function' (ARL) of both devices was set to start at the 0.5 setting and the rotary instrument inserted inside the root canal until a beeping sound was heard and the rotation of the file stopped automatically. Once the auto reverse function had been initiated, the foot pedal of the motor was inactivated and the rubber stop placed against the reference point. The distance between the file tip and rubber stop was measured using a digital calliper to 0.01 mm accuracy (ARL). Then, a size 20, 0.02 taper instrument was attached to each device and inserted into the root canals without rotary motion until the integrated ERCLMDs positioned the instrument tips at the 0.5 setting as suggested by the devices. This length was again measured using a digital calliper (EL). The Mann-Whitney U-test was used to investigate statistical differences between the true canal length and those indicated by the two devices when used in 'automatic ARL and when inserted passively (EL). In the presence of gutta-percha, sealer and chloroform, the auto-reverse function for the Tri Auto ZX and TCM Endo V, set to start at 0.5 level, was initiated beyond the foramen in 60% and 95% of the samples, respectively during active (rotary) penetration of the instruments. There was a statistically significant difference between the devices for the mean discrepancies between the length at which the auto reverse function was initiated and the true length (P < 0.001). Electronic detection of the apical terminus when the instruments were introduced passively (not rotating) was beyond the foramen in 20% and 37% of cases in the Tri Auto ZX group and the TCM Endo V group, respectively. There was a statistically significant difference between the devices for the mean discrepancies between the electronically determined (passive) length and true length (P < 0.01). The auto reverse function of the Tri Auto ZX and TCM Endo V devices, set to start at 0.5 level, were initiated beyond the foramen in the majority of root-filled teeth during active (rotating) penetration of root filling material. Thus, this automatic function must be used with caution when removing gutta-percha root fillings. There were significant differences between the accuracy of measurements in active (rotating) and passive (not-rotating) modes; both devices were more accurate when used in passive mode. However, the Tri Auto ZX was significantly more accurate in a greater proportion of cases.

Cytotoxicity of materials used in perforation repair tested using the V79 fibroblast cell line and the granulocyte‐macrophage progenitor cells

To compare the cytotoxicity of materials used to repair perforations using permanent V79 fibroblasts and murine granulocyte-macrophage progenitor cells (CFU-GM). Set specimens from amalgam, glass-ionomer, SuperEBA, N-Rickert, MTA and gutta-percha were eluted with culture medium for 72 h and their cytotoxicities were assessed by incubating the extracts with V79 and bone marrow-derived progenitors for 24 h and 7 days, respectively. Cytotoxicity on V79 cells was judged using the total nucleic acid content (NAC), neutral red uptake (NRU) and reduction of the tetrazolium salt (MTT). The number of bone marrow CFU-GM colonies determined in clonal cultures stimulated with recombinant murine granulocyte-macrophage colony-stimulating factor was used to assess cytotoxicity to progenitor cells. Statistical analyses were conducted using the one-way analysis of variance and Tukey's test where appropriate. All materials were cytotoxic in both cell systems; however, CFU-GM was more sensitive to the extracts than V79 cells. A similar rank order of toxicity was observed in V79 cells using the NAC and the MTT assays: glass-ionomer > N-Rickert congruent with SuperEBA > gutta-percha > amalgam congruent with MTA (P < 0.05). In contrast, the NRU test exhibited a lower sensitivity to MTA, gutta-percha and amalgam extracts. In the clonal culture assay, the toxicity was less pronounced in the presence of gutta-percha, SuperEBA and MTA. Similar cellular responses were found by placing the set specimens directly in the clonal culture dishes. The sensitivity of toxicity depended on the choice of the endpoint and the cell-culture system. Nevertheless, MTA was ranked as the least cytotoxic cement in both cell systems.

Resistance of a Novel Root Canal Sealer to Bacterial Ingress In Vitro

A dentin-bonding root canal sealer (ZUT) has been developed, consisting of an experimental glass ionomer cement (KT-308) and an antimicrobial silver-containing zeolite (0.2% by weight). This in vitro study evaluated the ability of ZUT used with or without gutta-percha, to resist bacterial ingress of Enterococcus faecalis over a period of 90 days. Canals of 80 single-rooted teeth were prepared with apical patency and filled as follows (n = 10): KT-308 alone; KT-308 with a single gutta-percha cone (SCGP); ZUT alone; ZUT with SCGP; AH26 alone; AH26 with SCGP; positive control-no root canal filling; and negative control-no root canal filling, with the apices of this group sealed with C&B Metabond cement. Teeth were coated with nail polish except for the apical 2 mm, and each tooth was sealed in a 4-ml glass vial, with an 18-gauge needle inserted through the vial cover and bonded into the pulp chamber with C&B Metabond cement. After sterilization with 2.5 Mrad gamma-radiation, Brain Heart Infusion broth with phenol red was injected into each vial. An inoculum of E. faecalis was pipetted through the needle into the pulp chamber every 5 days, and the broth was monitored daily for color change and turbidity. When change occurred, the broth was cultured for growth of E. faecalis. Kaplan-Meier survival analysis and the log-rank test revealed no significant differences among the three sealers used. The presence of gutta-percha, however, significantly improved resistance to bacterial ingress through obturated root canals (X, p < 0.05). Under the conditions of this study, the hypothesized advantage of ZUT (0.2% zeolite) was not demonstrated.