Association between IL-8 (-251T/A) and IL-6 (-174G/C) Polymorphisms and Oral Cancer Susceptibility: A Systematic Review and Meta-Analysis.

BACKGROUND AND OBJECTIVE: Inflammation and cell-mediated immunity can have significant roles in different stages of carcinogenesis. The present meta-analysis aimed to evaluate the association between the polymorphisms of IL-8 (-251T/A) and IL-6 (-174G/C) and the risk of oral cancer (OC). METHODS: PubMed/MEDLINE, Web of Science, Cochrane Library, and Scopus databases were searched until December 18, 2020 without any restrictions. RevMan 5.3 software was used to calculate the results of forest plots (odds ratios (ORs) and 95% confidence intervals (CIs)); CMA 2.0 software was used to calculate funnel plots (Begg's and Egger's tests), and SPSS 22.0 was used for the meta-regression analysis. Moreover, trial sequential analysis was conducted to estimate the robustness of the results. RESULTS: Eleven articles including twelve studies were selected for the meta-analysis. The pooled ORs for the association between IL-8 (-251T/A) polymorphism and the risk of OC in the models of A vs. T, AA vs. TT, TA vs. TT, AA + TA vs. TT, and AA vs. TT + TA were 0.97 (p = 0.78), 0.86 (p = 0.55), 0.78 (p = 0.37), 0.83 (p = 0.45), and 1.10 (p = 0.34), respectively. The pooled ORs IL-6 (-174G/C) polymorphism and the risk of OC in the models of C vs. G, CC vs. GG, GC vs. GG, CC + GC vs. GG, and CC vs. GG + GC were 1.07 (p = 0.87), 1.17 (p = 0.82), 1.44 (p = 0.38), 1.28 (p = 0.61), and 0.96 (p = 0.93), respectively. There was no association between IL-8 (-251T/A) polymorphism and OC susceptibility, but the C allele and GC and CC genotypes of IL-6 (-174G/C) polymorphism were associated with the risk of OC based on subgroup analyses, that is to say, the source of control and the genotyping method might bias the pattern of association. CONCLUSIONS: The meta-analysis confirmed that there was no association between the polymorphisms of IL-6 (-174G/C) and IL-8 (-251T/A) and the susceptibility of OC. However, the source of control and the genotyping method could unfavorably impact on the association between the polymorphisms of IL-6 (-174G/C) and the risk OC.

Endodontic Rotary Systems: Comparison between Gentlefile and Pro Taper Universal for removal of Enterococcus faecalis.

Background: As a resistant bacterium species in infected root canals, Enterococcus faecalis needs to be removed in any endodontic treatment. So, we aimed to compare the effectiveness of two rotary systems, Gentlefile and Pro Taper Universal, in removing Enterococcus faecalis (E. faecalis) from the infected root canal system. Material and Methods: Forty single-root premolar teeth were collected and randomly divided into two groups: Gentlefile (n=18) and Pro Taper Universal (n=18). In addition, four teeth were used as a negative control. The root canals were prepared and infected with E. faecalis and incubated for 4 weeks. Samples were obtained from the root canal immediately before and after instrumentation. A reduction in bacteria was determined by the colony count method. Results: Colony numbers of E. faecalis were significantly different before and after instrumentation in all groups (p<0.001). Furthermore, Gentlefile group illustrated a higher percentage of bacterial reduction (96.1%) compared to Pro Taper Universal group (90%). Accordingly, Gentlefile group was found to be significantly (p<0.001) more effective in decreasing bacterial populations than Pro Taper Universal group. Conclusions: Although both rotary systems were highly effective in bacterial reduction from root canals, Gentlefile demonstrated better bacterial reduction percentage from root canals than Pro Taper Universal. Key words:Enterococcus faecalis, Gentlefile, Pro Taper Universal, Rotary systems.

Simulated Evaluation of Tooth Fracture Resistance during Instrumentation with Single-and Multi-file Rotary Systems.

Introduction: Use of rotary files in root canal preparation is inevitable due to their high speed and reduced duration of treatment. However, microcracks and even root fracture may sometimes occur in teeth where canal(s) is/are prepared using these devices. The purpose of the current study was to compare NeoNiti single-file with RaCe multi-file rotary systems. Materials and Methods: An accurate scanner designed detailed three-dimensional file models, and a simulated model was developed using canal-specific features; including dentin thickness, root canal length, taper rate and root canal curvature. Cleaning and shaping conditions were simulated with appropriate speed and crack conditions for both types of files on the computer. Strain accumulation sites in the root dentin wall where microcracks was likely to occur were simulated and investigated. Abaqus and ANSYS software were used to perform finite element simulations. Results: RaCe files with 0.04 taper caused the lowest level of stress (34.33 MPa) to the simulated canal. Conversely, the highest level of stress (62.35 MPa) was applied by 8% NeoNiti file to the simulated canal. Conclusions: Based on the present experimental study, it can be concluded that RaCe multi-file rotary system may better be used in endodontic therapy, and the risk of microcracks in the tooth wall is less than that of NeoNiti single-file rotary system.

The Most Common Vitamin D Receptor Polymorphisms (ApaI,FokI, TaqI, BsmI, and BglI) in Children with Dental Caries: A Systematic Review and Meta-Analysis.

Vitamin D participates in the calcification of enamel and dentin and the appropriate immune responses to oral microbial infections. We aimed to assess the association between the most common vitamin D receptor (VDR) polymorphisms (ApaI,FokI, TaqI, BsmI, and BglI) and the risk of dental caries in children. METHODS: PubMed/MEDLINE, Cochrane Library, Web of Science, and Scopus databases were comprehensively searched until 19 January 2021. Meta-analysis with odds ratios as the effect estimate along with 95% confidence intervals and subgroup analysis were conducted using Review Manager 5.3 software. Publication bias and sensitivity analyses were conducted by Comprehensive Meta-Analysis, version 2.0 software. RESULTS: Seventy-eight studies were retrieved from the databases, with nine studies included in the final analysis. Based on five genetic models, there was no association between ApaI (rs7975232), TaqI (rs731236), BsmI (rs1544410), FokI (rs2228570), and BglI (rs739837) polymorphisms and susceptibility to dental caries, except for the FokI (rs10735810) polymorphism. CONCLUSION: Among the VDR polymorphisms considered, an association was found between the FokI (rs10735810) polymorphism and the risk of dental caries, with a protective role of the f allele and ff genotype.

Hydrophilic Natural Polymers for Sustained-controlled Release of Calcium Hydroxide.

Calcium Hydroxide (CH) is commonly employed as intracanal medicament in endodontics. In order to maximize its therapeutic effects, it is essential to develop new approaches for preparing the controlled drug release systems which, in turn, facilities the dissociation of CH into calcium and hydroxyl ions. This work studies the sustained-controlled release of calcium ions and the effect of pH changes on the different formulation of CH with hydrophilic natural polymers over a period of 30 days. Various formulations were prepared by combining CH with gelatin, aloe vera and gum tragacanth. Root canals of 60 human teeth were instrumented and filled with a different formulation of CH and suspended in plastic tubes containing distilled water. Three formulas of polymer/CH were evaluated, and pure CH powder was used as a control. At specific time intervals, the calcium ions release and the pH changes of the medium in different formulations were analyzed. The main interactions between the studied polymers and CH were investigated using FTIR spectra. The antibacterial activity of formulations against Enterococcus faecalis was also studied. Faster release of CH was observed for aloe vera/CH. Gum tragacanth/CH showed a slow-release during the first 15 days. In contrast, only Gelatin/CH formulation showed a prolonged release with statistically significant differences (P < 0.05). The pure CH showed significantly higher pH values than the other formulations. The Gelatin/CH formulation was a better sustained-release system than the pure CH, and it can be used as a promising vehicle for CH in the root canal treatment.

In vitro evaluation of coronal discoloration following the application of calcium-enriched mixture cement, Biodentine, and mineral trioxide aggregate in endodontically treated teeth.

BACKGROUND: This study sought to assess and compare coronal discoloration following the application of white mineral trioxide aggregate, Biodentine, and calcium-enriched mixture cement in endodontically treated teeth. MATERIALS AND METHODS: In this in vitro experimental study, 64 freshly extracted sound human premolars were selected, cleaned, and stored in saline. After cleaning, shaping, and obturation the root canal of the teeth, the teeth were randomly assigned to one control (n = 4) and three experimental (n = 20) groups. In the experimental groups, the cement were applied over the canal orifices in 3-mm thickness. All teeth were then restored with composite resin. Color parameters, according to the CIE L*a*b* system, were measured using Vita Easyshade spectrophotometer before application of cement and at 1 week, 1 month, 2 months, and 3 months after the application of cement. The recorded values were statistically analyzed using descriptive and analytical statistics. For analytical statistics, Kolmogorov-Smirnov test was applied to assess normal distribution of data. ANOVA was used to compare the results at baseline and repeated measures. P < 0.05 was considered statistically significant. RESULTS: Significant differences were noted in color change (ΔE) between all time points except between ΔE4 (2 months) and ΔE5 (3 months) (P < 0.01). However, tooth discoloration caused by the three cement was not significantly different (P = 0.343). CONCLUSION: The three tested cement were not significantly different in terms of causing coronal discoloration in endodontically treated teeth.

Effect of Topical Application of Dentol Drop on the Success of Inferior Alveolar Nerve Block for Teeth with Irreversible Pulpitis: A Double-blind Randomized Clinical Trial.

Introduction: The failure rate of inferior alveolar nerve (IAN) block is high for mandibular molars with irreversible pulpitis. This double-blind, randomized, clinical trial aimed to assess the effect of topical application of Dentol drop on the rate of successful anaesthesia of mandibular molars with irreversible pulpitis due to deep carious lesions. Methods and Materials: Seventy-two patients with mandibular first and second molars with irreversible pulpitis and deep cavitated carious lesions participated in this study. The patients were randomly assigned to the test and control groups (n=36). In the test group, a cotton pellet, dipped in Dentol drop, was placed in the cavity for 10 min. A placebo was used _in the same manner_ in the control group. Level of pain was measured before the intervention, 15 min after anaesthesia (when patients reported numbness at the corner of the mouth), during access cavity preparation, upon pulp exposure and after introduction of the initial file into the root canal; using a Heft-Parker "Visual Analog Scale" (VAS). Data were analysed using ANCOVA. Results: Levels of pain were recorded during access cavity preparation (P<0.001), pulp exposure (P<0.001) and file introduction into the canal (P=0.018). In the test (Dentol) group, the obtained levels of pain were significantly lower than those of the corresponding values in the control group. Conclusion: Topical application of Dentol drop increased the success rate of IAN block for root canal treatment of mandibular molars with irreversible pulpitis.

Performance of Cone Beam Computed Tomography Systems in Visualizing the Cortical Plate in 3D Image Reconstruction: An In Vitro Study.

INTRODUCTION: Cortical bone is an important anatomical structure and its thickness needs to be determined prior to many dental procedures to ensure treatment success. Imaging modalities are necessarily used in dentistry for treatment planning and dental procedures. Three-dimensional image reconstruction not only provides visual information but also enables accurate measurement of anatomical structures; thus, it is necessarily required for maxillofacial examination and in case of skeletal problems in this region. AIMS: This study aimed to assess the ability of three Cone Beam Computed Tomography (CBCT) systems including Cranex 3D, NewTom 3G and 3D Promax for Three-Dimensional (3D) image reconstruction of the cortical plate with variable thicknesses. METHODS: Depending on the cortical bone thickness, samples were evaluated in three groups of ≤ 0. 5 mm, 0.6 -1 mm and 1.1-1.5 mm cortical bone thickness. The CBCT scans were obtained from each sample using three systems, their respective FOVs, and 3D scans were reconstructed using their software programs. Two observers viewed the images twice with a two-week interval. The ability of each system in the 3D reconstruction of different thicknesses of cortical bone was determined based on its visualization on the scans. The data were analyzed using SPSS and Kappa test. RESULTS: The three systems showed the greatest difference in the 3D reconstruction of cortical bone with < 0.5 mm thickness. Cranex 3D with 4×6 cm2 FOV had the highest and 3D Promax with 8×8 cm2 FOV had the lowest efficacy for 3D reconstruction of cortical bone. Cranex 3D with 4×6 cm2 and 6×8 cm2 FOVs and NewTom 3G with 5×5 cm2 and 8×5 cm2 FOVs showed significantly higher efficacy for 3D reconstruction of cortical bone with 0.6-1mm thickness while 3D Promax followed by NewTom 3G with 8×8 cm2 FOV had the lowest efficacy for this purpose. CONCLUSION: Most CBCT systems have high efficacy for 3D image reconstruction of cortical bone with thicknesses over 1 mm while they have poor efficacy for image reconstruction of cortical bone with less than 0.5 mm thickness. Thus, for accurate visualization of anatomical structures on CBCT scans, systems with smaller FOVs and consequently smaller voxel size are preferred.

Chitosan/gelatin as a new nano-carrier system for calcium hydroxide delivery in endodontic applications: Development, characterization and process optimization.

The main aim of this study is preparation, optimization and in vitro characterization of Chitosan/Gelatin nano-carriers (NCs) for calcium hydroxide (CH) to improve its therapeutic potential. The designed system can be used in the endodontic applications demanding a sustained release of calcium and hydroxyl ions. Modeling and optimization of CH loaded polymeric NCs were performed using response surface methodology (RSM) based on central composite surface statistical design. The effect of Chitosan concentration (0.1-1% w/v), Gelatin concentration (0.1-1% w/v) and CH concentration (0.05-0.4% w/v) on the particle size, polydispersity index (PDI), drug loading (DL) and encapsulation efficiency (EE) of CH loaded polymeric NCs were investigated. Optimized CH loaded polymeric NCs formulation which obtained using RSM showed spherical and smooth surface with a particle size of 292 nm, PDI of 0.32, DL of 88.8% and EE of 99%. Optimized formulation was evaluated for in vitro calcium ion release in phosphate buffer solution (PBS) at pH 7.4 for 14 days. The presence of hydrogen bonding and some intermolecular interactions between Chitosan/Gelatin polymeric materials were confirmed using Fourier transform infrared (FTIR) analysis. These interactions enable Chitosan/Gelatin NCs to load CH and maintain sustained release of Calcium ions from CH during experimental period.

Apical Microleakage in Root Canals Containing Broken Rotary Instruments.

INTRODUCTION: Broken instruments in root canals complicate routine endodontic treatment. This study aimed to compare apical microleakage in root canals containing broken rotary instruments filled with mineral trioxide aggregate (MTA), calcium-enriched mixture (CEM) cement, laterally compacted gutta-percha and injected gutta-percha. METHODS AND MATERIALS: In this in vitro, experimental study, 80 extracted human premolars were decoronated and then the roots were randomly divided into four groups (n=20). Root canals were instrumented with Mtwo rotary files. The files were scratched 3 mm from the tip by a high speed handpiece and they were intentionally broken in the apical third of the canals. The middle and coronal thirds of the canals were then filled with MTA, CEM cement, gutta-percha with lateral compaction technique and injected gutta-percha. Apical microleakage was measured using dye penetration method. Data were analyzed using ANOVA and Tukey's test. RESULTS: Root canals filled with CEM cement showed the lowest and those filled with injected gutta-percha showed the highest microleakage according to dye penetration depth. No significant difference was noted between the microleakage of CEM cement and MTA or between lateral compaction of gutta-percha and injected gutta-percha (P>0.05). However, CEM cement and MTA groups had significantly lower microleakage than laterally compacted and injected gutta-percha groups (P<0.05). CONCLUSION: Due to their superior sealing ability, MTA and CEM cement are suitable for filling of root canals containing a broken instrument compared to laterally compacted and injected gutta-percha.

Comparison of the Antibacterial Effect of 810 nm Diode Laser and Photodynamic Therapy in Reducing the Microbial Flora of Root Canal in Endodontic Retreatment in Patients With Periradicular Lesions.

INTRODUCTION: The aim of this study was to compare the antibacterial efficacy of diode laser 810nm and photodynamic therapy (PDT) in reducing bacterial microflora in endodontic retreatment of teeth with periradicular lesion. METHODS: In this in vivo clinical trial, 20 patients who needed endodontic retreatment were selected. After conventional chemo mechanical preparation of root canals, microbiological samples were taken with sterile paper point (PP), held in thioglycollate broth, and then were transferred to the microbiological lab. In the first group, PDT with methylene blue (MB) and diode laser (810 nm, 0.2 W, 40 seconds) was performed and in the second group diode laser (810 nm, 1.2 W, 30 seconds) was irradiated. Then second samples were taken from all canals. RESULTS: CFU/ml amounts showed statistically significant reduction in both groups (P < 0.001). CFU/ml amounts were compared between the two groups and there was no statistical difference. CONCLUSION: PDT and diode laser 810 nm irradiation are effective methods for root canal disinfection. PDT is a suitable alternative for diode laser 810 nm irradiation, because of lower thermal risk on root dentin.

Effect of Experience in Landmark Identification on 2D Lateral Cephalograms on Performance of Dental Students Concerning Landmark Identification on 3D Cone Beam Computed Tomography Scans

Abstract Objective: To assess the effect of experience in landmark identification on two-dimensional (2D) lateral cephalograms on performance of dental students concerning landmark identification on three-dimensional (3D) cone-beam computed tomography (CBCT) scans. Material and Methods: This quasi-experimental study evaluated 40 dental students in two groups (n=20). Group 1 included senior dental students who had experience in landmark identification on 2D lateral cephalograms and Group 2 included third-year dental students with no such experience. Both groups received instructions on identification of eight landmarks on 3D CBCT scans. The coordinates of the landmarks were determined in x, y and z axes. One orthodontist determined the mean coordinates of each landmark as a reference by twice measurements with a one-week interval. The mean distance from the identified points to the reference points was reported as the mean consistency (MC), and the standard deviation of the mean was considered as precision of landmark identification. Data were analyzed using independent samples t-test. Results: The mean distances from the points identified as nasion, point B, orbitale, anterior nasal spine (ANS), menton, coronoid process and pogonion in x, y and z axes and point A in x and z axes (p<0.001) to the reference points in Group 1 were greater than those in Group 2 with no such experience. Conclusion: Previous experience in landmark identification on 2D cephalograms does not help in landmark identification on 3D CBCT scans and may even adversely affect the results.

The comparison of the rate of apical displacement in curved root canals using Neoniti and RaCe files by cone beam CT Scan / Comparação da taxa de desvio apical em canais radiculares curvos utilizando limas Neoniti e RaCe por meio de tomografia computadorizada cone beam (TCCB)

Objective: There is a high prevalence of root canal transportation in the teeth with the curve. Effect of root canal transportation on the success of root canal therapy of tooth is negative and there is no study about comparing RaCe and Neoniti files in root canal transportation. The aim of this study is assessment and comparing two different RaCe and Neoniti files to determine transportation error in various parts of root using CBCT assessment and comparing them with each other. Material and Methods: In this experimental study 50 extracted mandibular molar teeth selected. Teeth were divided randomly into two groups i.e. 25 teeth threated with RaCe file (first group) and 25 teeth threated with Neonitu files (second group). CBCT images were used to measurement thickness of dentine, before and after instrumentation that obtain from NNT viewer 6.1.0 software. Results: In the first group, the mean tooth transportation in 5 mm of apex was 0.15 and, in the second group, the mean tooth transportation in 5 mm of apex was 0.18 mm. There was no statistically significant difference in canal transportation between RaCe and Neoniti files in five millimeters distant from apex area (p = 0.492) and the mean transportation from 9 mm of apex were 0.14 in the second group. There was no statistically significant difference in canal transportation between two groups (p = 0.911). Conclusion: In comparison of these two rotary files, both are equally safe regarding the extent of apical transportation. (AU)

Objetivo: Existe uma alta prevalência de desvio apical em canais radiculares curvos. O efeito do desvio apical no canal radicular sobre o sucesso da terapia endodôntica é desfvorável e não há nenhum estudo comparando as limas RaCe e Neoniti em relação ao desvio apical dos canais radiculares durante o preparo. O objetivo deste estudo é avaliar e comparar duas diferentes limas, RaCe e Neoniti, a fim de para determinar o erro de desvio em várias porções radiculares através de análise por TCCB e compará-los entre eles. Material e Métodos: Neste estudo experimental, 50 dentes molares mandibulares extraídos foram selecionados. Os dentes foram divididos aleatoriamente em dois grupos, ou seja, 25 dentes preparados com as limas RaCe (primeiro grupo) e 25 dentes preparados com limas Neoniti (segundo grupo). Neste estudo para medir a espessura da dentina através do escaneamento, antes e depois da instrumentação, ao mesmo tempo, usamos imagens axiais obtidas do software NNT viewer 6.1.0. Resultados: No primeiro grupo, o desvio apical médio a 5 mm do ápice foi de 0,15 e no segundo grupo o desvio apical médio a 5 mm do ápice foi de 0,18 mm, não havendo diferença estatisticamente significante entre as limas RaCe e Neoniti a cinco milímetros da porção apical (p = 0,492) e o transporte médio a 9 mm do ápice foi de 0,14 no segundo grupo não havendo diferença estatisticamente significante no desvio apical entre os dois grupos (p = 0,911). Conclusão: Os resultados indicaram que não houve diferença significativa no desvio apical médio entre dois sistemas de limas em 3, 9, 7, 5 e 11 mm do ápice e ambos as limas foram seguras (AU)