Effect of White-Colored Mineral Trioxide Aggregate in Different Concentrations on Candida albicans In Vitro
Khalid Al-Hezaimi, BDS, Khalid Al-Hamdan, BDS, MS, Jafar Naghshbandi, DDS, Samuel Oglesby, DDS, James H.S. Simon, DDS, and Ilan Rotstein, DDS
The antifungal action of different concentrations of white-colored mineral trioxide aggregate (MTA) against Candida albicans was assessed in vitro. Fresh mix of MTA was prepared at concentrations varying from 0.78 mg/ml to 50 mg/ml by dilution with 10 ml molten agar at 45°C. The MTA-agar compound was thoroughly mixed and the uniform mix was then poured into sterile Petri dishes and allowed to set. A total of 348 agar plates were prepared and divided into experimental groups of 11 plates each and control groups of 5 plates each. Plates of agar without MTA served as positive control and plates without C. albicans served as negative control. Fresh inoculate of C. albicans was prepared by growing an overnight culture from a stock culture. Aliquots of C. albicans were then taken from the stock culture and plated on the agar compound of the experimental and positive control groups. All plates were incubated at 37°C for 1, 24, 48, and 72-h periods. At each time period, the presence of C. albicans colonies was assessed and recorded. A direct correlation was found between MTA concentration and its inhibition effect on C. albicans growth. Plates containing MTA in concentration of 50 mg/ml showed significantly better killing action against C. albicansin all of the time periods tested (p < 0.001). Plates containing MTA in concentration of 25 mg/ml showed antifungal activity only at 1 and 24-h time periods. Plates containing lower concentrations of MTA did not show any antifungal activity. It appears that under the conditions of this study, white-colored MTA in concentration of 50 mg/ml is effective in killing C. albicans for periods of up to 3 days. Lower MTA concentrations may not be effective.
Induction of Interleukin-6 and Interleukin-8 Gene Expression by Root Canal Sealers in Human Osteoblastic Cells
Fu-Mei Huang, DDS, MS, Chung-Hung Tsai, DDS, MPH, Shun-Fa Yang, MS, and Yu-Chao Chang, DDS, MS, PhD
Histological investigations have demonstrated that root canal sealers can induce mild to severe inflammatory alternations. However, there is little information on the precise mechanisms about root canal sealers-induced inflammatory reaction. Dysregulated cytokine productions at local disease sites have been considered to be major contributors to the development of inflammatory diseases. Interleukin (IL)-6 and IL-8 released have been reported to play an important role in the pathogenesis of inflammation. The aim of this study was to investigate the effects of root canal sealers N2 (zinc-oxide eugenol based) and AH Plus (epoxy resin based) on the expression of IL-6 and IL-8 mRNA gene in human osteoblastic cell line U2OS cells. The levels of mRNAs were measured by the semi-quantitative reverse-transcriptase polymerase chain reaction analysis. The exposure of quiescent U2OS cells to N2 and AH Plus resulted in the induction of IL-6 and IL-8 mRNA gene expression (p < 0.05). The intensity of IL-8 mRNA gene was found to be significant higher than IL-6 mRNA gene (p < 0.05). Taken together, the activation of IL-6 and IL-8 mRNA gene expression may be one of the pathogenesis of zinc oxide-eugenol based and epoxy resin based root canal sealers-induced periapical inflammation.
In Vitro Evaluation of the Ability of Three Apex Locators to Determine the Working Length During Retreatment
Fernando Goldberg, DDS, PhD, Benjamín Briseño Marroquín, DMD, Santiago Frajlich, DDS, and Cristian Dreyer, DDS
The purpose of this in vitro study was to evaluate the accuracy of three apex locators in determining the working length during the retreatment process. Twenty extracted single-rooted human teeth with mature apices were used in this study. The root canal length of each tooth was measured placing a #15 file until the tip was visible at the apical foramen. The direct visual measurement was reduced by 0.5 mm and recorded. The root canals were instrumented and filled to the direct visual measurement using lateral compaction technique. After 7 days the teeth were retreated using three apex locators: ProPex, NovApex, and Root ZX, for determining the retreatment working length. Afterward, comparison between the visual working length and the retreatment working length were made. ProPex, NovApex, and Root ZX were accurate within 0.5 mm 80, 85, and 95% of the time, and within 1 mm 95, 95, and 100%, respectively. No significant differences were detected between the three apex locators (p > 0.05).
Properties of a New Root-End Filling Material
Hui Kheng Chng, MDSc, Intekhab Islam, MSc, Adrian U Jin Yap, PhD, Yen Wah Tong, PhD, and Eng Tiong Koh, MSc
The purposes of this investigation were 2-fold: to study the physical properties and sealing ability of Viscosity Enhanced Root Repair Material (VERRM); and, to compare them with Mineral Trioxide Aggregate (MTA). VERRM has a composition similar to mineral trioxide aggregate, with handling characteristics and consistency similar to commercially available materials such as IRM and Super EBA. The pH, setting times, solubility, radiopacity, dimensional change upon setting, and apical sealing ability of VERRM were evaluated and compared to that of ProRoot MTA (GMTA) and ProRoot MTA (Tooth Colored Formula) (WMTA). The results showed that VERRM had physical properties similar to WMTA. VERRM and WMTA showed significantly greater dye penetration than GMTA (p < 0.05) when used as a root-end filling material. There was no significant difference in depth of dye penetration between VERRM and WMTA. Further development of VERRM is indicated to produce a biocompatible root-end filling material with superior handling characteristics.
An In Vitro Evaluation of the Antibacterial Efficacy of Chlorine Dioxide on E. faecalis in Bovine Incisors
Russell S. Eddy, DMD, Anthony P. Joyce, DDS, Steven Roberts, DDS, Thomas B. Buxton, PhD, and Frederick Liewehr, DDS, MS
This study investigated the ability of chlorine dioxide to eliminate Enterococcus faecalis from dentinal tubules of bovine incisors. Thirty-seven extracted bovine incisor roots were sectioned into seventy-four 5 mm disks. Standardized lumens were filled with either sterile Brain Heart Infusion Broth (contamination controls, n= 10) or BHI containing E. faecalis (1.0 × 10⁸ cfu/ml). Disks were incubated in 5% CO₂ at 37°C for 72 h. To simulate endodontic instrumentation the lumens were again enlarged. Sixty disks were randomly divided into four experimental groups and filled with one of the following irrigants: 10% Clidox-S (chlorine dioxide),13.8% BioClenz (chlorine dioxide), 5.25% Clorox, or saline. The disks were incubated for 30 min and were then frozen, pulverized, serially diluted in phosphate buffered saline, and plated on BHI plates in triplicate. Total colony forming units were counted macroscopically. Statistical analysis of the data was performed with a Kruskal-Wallis one-way ANOVA on ranks (p < 0.05, n = 60). Bacterial counts, expressed in log10 cfu/disk were as follows (“>” denotes significant differences): Saline > Clidox-S = BioClenz > Clorox. All negative controls were sterile. Chlorine dioxide and NaOCL were both effective in eliminating E. faecalis from the dentinal disks within 30 min.
The Effects of Temperature on Sodium Hypochlorite Short-Term Stability, Pulp Dissolution Capacity, and Antimicrobial Efficacy
George Sirtes, DMD, Tuomas Waltimo, DMD, PhD, Marc Schaetzle, DMD, and Matthias Zehnder, DMD
The purpose of this study was to test some effects of preheating NaOCl solutions using a commercially available syringe heating device. Irrigating solution temperatures in 10-ml syringes were measured. Stability of 5.25, 2.62, and 1% NaOCl solutions for 60 min at 20, 45, and 60°C was assessed using iodine/thiosulfate titration. Human pulp tissue dissolution capacity of a 1% NaOCl solution was gauged at the latter temperatures, and compared to corresponding values with a 5.25% solution at 20°C. Killing efficacy of diluted NaOCl solutions against 48-h incubations of Enterococcus feacalis ATCC 29212 was compared at 45°C and 20°C. Using the heating device, a 20°C solution reached 45°C and 60°C in 7 and 20 min, respectively. Solutions remained stable during the observation period. The 1% NaOCl solution at 45°C dissolved pulp tissues as effectively as the 5.25% solution at 20°C, while the 60°C/1% solution was significantly more effective (p <0.05). A 100-fold increase in killing efficacy was observed between corresponding NaOCl solutions at 20°C and 45°C.
Effectiveness of Resin-Coated Gutta-Percha Cones and a Dual-Cured, Hydrophilic Methacrylate Resin-Based Sealer in Obturating Root Canals
Franklin R. Tay, BDSc (Hons), PhD, Robert J. Loushine, DDS, Francesca Monticelli, DDS, R. Norman Weller, DMD, MS, Lorenzo Breschi, DDS, PhD, Marco Ferrari, DDS, PhD, and David H. Pashley, DMD, PhD
The introduction of a polybutadiene-diisocyanatemethacylate resin-coating of gutta-percha enables the polyisoprene to be chemically coupled to methacrylatebased resin root canal sealers. This study examined the effectiveness of using passively fitting cones of this type of gutta-percha with a dual-cured version of EndoREZ sealer in obturating cleaned and shaped root canals. The hydrophilic nature of the sealer enabled the creation of an extensive network of 800 to 1200 _m long sealer resin tags after removal of the endodontic smear layer. Although no adhesive was employed, thin hybrid layers in root dentin were observed when EDTA was used as the final rinse. Nevertheless, interfacial gaps and silver leakage could be observed along the sealerdentin interfaces that might be attributed predominantly to polymerization shrinkage of the sealer. Gaps and silver leakage were also identified between the gutta-percha resin-coating and the sealer.
Effect of Iontophoretical Application of NK1 Receptor Antagonists on Pulpal Blood Flow in Cats
Young-Kyung Kim, DDS, PhD, Wan-sik Chu, DDS, MsD, Ho-Jeong Lee, BSc, Dong-Kuk Ahn, DDS, PhD, and Sung Kyo Kim, DDS, PhD
The influence of NK1 receptor antagonists applied iontophoretically on pulpal blood flow (PBF) was investigated. Along with substance P (SP, 0.8_20.0 ng/kg) administration to the canine pulp through the catheterized lingual artery, two NK1 receptor antagonists, [D-Pro2,D-Trp7,9]-SP and [D-Pro2,D-Phe7,D-Trp9]-SP (0.2_3.4 mM) were applied iontophoretically (cathodal current, 0.02_0.1 mA, 1 min) to the prepared class V dentinal cavity of ipsilateral teeth in 11 generally anesthetized cats. A paired t-test showed that SP administration caused significant increases of PBF (p < 0.05) without changing systemic blood pressure, and that SP and SP antagonist administration caused significantly less increase of PBF than in control of SP and 0.9% saline administration (p < 0.05). These data provide evidence that the iontophoretic application of NK1 receptor antagonists effectively attenuates SP-induced vasodilatation and show the possibility of their use in the control of neurogenic inflammation in the dental pulp.
Detection of a Residual Foreign Body During Root Canal Treatment
Emmanuel Mazinis, DDS, Theodore Lambrianidis, DDS, and John Margelos, DDS
A 25-yr old female with a 12-month history of orofacial trauma was referred to us with acute pain with positive percussion of the left mandibular first premolar and swelling in the left-posterior mandibular area. The diagnosis was pulpal necrosis with acute apical abscess. Both preoperative and length determination radiographs revealed a semi-opaque area on the root of the first premolar that was later identified as a residual fragment of windshield left in the soft tissues. Thorough medical record, clinical and radiographic examination may be helpful in the detection of foreign bodies in the orofacial region.
Levels of Evidence for the Outcome of Nonsurgical Endodontic Treatment
Mahmoud Torabinejad, DMD, MSD, PhD, Diana Kutsenko, DMD, Tanya K. Machnick, DDS, MS, Amid Ismail, BDS, MPH, DPH, and Carl W. Newton, DDS, MSD
The purpose of this systematic review was (a) to search for clinical articles pertaining to success and failure of nonsurgical root canal therapy, and (b) to assign levels of evidence to these studies. Electronic and manual searches were conducted to identify studies published between January 1966 and September 2004 with information on the success and failure of nonsurgical root canal therapy. Articles were reviewed and graded for strength of level of evidence (LOE) from one (highest level) to five (lowest level). This review resulted in the identification of 306 clinical studies related to this topic area. Six articles were randomized controlled trials (RCTs, LOE 1). This search also identified 12 low-quality RCTs (LOE 2), 14 cohort studies (LOE 2), five casecontrol and eight cross sectional studies (LOE 3), four low-quality cohort studies (LOE 4), and five low-quality case-control studies (LOE 4). The majority (73) of the often-quoted “success and failure” studies were case series (LOE 4). The rest of the articles were descriptive epidemiological studies (42), case reports (114), expert opinions (18), literature reviews (4), and one metaanalysis. Based on these findings, it appears that a few high-level studies have been published in the past four decades related to the success and failure of nonsurgical root canal therapy. The data generated by this search can be used in future studies to specifically answer questions and test hypotheses relevant to the outcome of nonsurgical root canal treatment.
Expression and Characterization of Vanilloid Receptor Subtype 1 in Human Dental Pulp Cell Cultures
Rie Miyamoto, DDS, Masayuki Tokuda, DDS, PhD, Tetsuya Sakuta, DDS, PhD, Shigetaka Nagaoka, DDS, PhD, and Mitsuo Torii, DDS, PhD
The expression of the vanilloid receptor subtype 1 (VR1, TRPV1) was detected in human dental pulp fibroblasts (PF-10) using RT-PCR, Western blotting, and immunocytochemical analysis. As revealed by ELISA, capsaicin induced IL-6 expression in PF-10 cells, and the VR1 antagonist capsazepine dose-dependently inhibited capsaicin-induced IL-6 production, indicating that capsaicin- induced IL-6 expression is related to VR1 activation. The interaction between capsaicin and mitogenactivated protein kinases (MAPKs) was investigated. The phosphorylation of p38 MAPK and c-Jun NH₂- terminal kinase (JNK) were detected after capsaicin stimulation. p38 MAPK is involved in capsaicin-induced IL-6 production, as shown by the use of specific inhibitors of this kinase. The result of EMSA showed that capsaicin inhibited tumor necrosis factor-alpha (TNF- α)-induced nuclear factor-kappa B (NF-κB) activation in PF-10 cell cultures. These results suggest that the activation of VR1 plays an important role in dental pulp inflammation.
Homogeneity and Adaptation of a New Gutta-Percha Paste to Root Canal Walls
Ashraf ElAyouti, DMD, Christian Achleithner, DMD, Claus Lo¨st, DMD, and Roland Weiger, DMD
A new flowable root canal filling material (GuttaFlow) was tested. Under simulated clinical conditions, the middle and coronal thirds of 90 human teeth with 169 root canals were shaped with 6% taper rotary HERO instruments and the apical third with rotary LightSpeed instruments. The root canals were divided into three similar groups and were filled with GuttaFlow (GF), conventional cold laterally condensed gutta-percha (LC), and warm vertically condensed gutta-percha (VC). Roots were sectioned at five levels, digitally photographed and traced. The percentage of voids area showed a statistically significant difference between GF and both LC and VC [GF 1.9% (95% CI = 1.4 –2.4), LC 4.4% (95% CI = 2.2– 6.6), VC 6.8% (95% CI = 5.4– 8.1)]. The frequency of voids was significantly different between all groups [GF 37% (95% CI = 34%–40), LC 10% (95% CI = 8–12), VC 22% (95% CI = 19–24)]. In most sections, GuttaFlow completely filled the prepared root canal, but small voids were frequently present within the core of the filling material.
The Effect of Human Immunodeficiency Virus on Endodontic Treatment Outcome
Brian T. Quesnell, DDS, Mario Alves, DDS, MS, DSc, Robert W. Hawkinson, Jr., DDS, MS, Bradford R. Johnson, DDS, Christopher S. Wenckus, DDS, and Ellen A. BeGole, PhD
The purpose of this retrospective study was to compare periradicular healing between HIV positive and negative patients 1 yr after endodontic treatment of necrotic teeth with chronic apical periodontitis. The preoperative radiographs of 33 patients diagnosed with HIV and 33 medically healthy patients were scored by three endodontists using the Periapical Index (PAI) Scoring Method. Follow-up radiographs were taken 12 months after endodontic treatment and also scored with the PAI. The degree of healing, as determined by the mean PAI change, was compared between the two groups. There were no statistically significant differences between the two with respect to the degree of periradicular healing. In addition, the three evaluators were found to have very high inter-examiner agreement. The results indicate that clinicians do not have to alter their expectations for healing and resolution of periradicular lesions based solely on the HIV status of their patients.