Comparison of propolis and calcium hydroxide in terms of mineralization and cytotoxicity using dental pulp stem cells

Objectives: this study aimed to compare the in vitro cytotoxic activity of propolis, a bioactive material made by the honeybee, and calcium hydroxide [CH] and their effect on formation of mineralized nodules by human dental pulp stem cells [HDPSCs]

Methods: in this in vitro study, HDPSCs were obtained from the Cellular and Molecular Oral Biology Laboratory of School of Dentistry, Shahid Beheshti University of Medical Sciences. In order to evaluate the proliferative effect of propolis and CH, HDPSCs were incubated with different concentrations of propolis [0-32mg/mL] and CH [0-4.8 mg/mL]. Twenty-four and 48 hours later, the methylthiazolyl diphenyl-tetrazolium bromide [MTT] assay was carried out to evaluate the proliferation potential and viability of HDPSCs treated with propolis and CH. The effect of propolis and CH on mineralization of HDPSCs was assessed by alizarin red staining

Results: the MTT assay revealed that propolis at its highest concentration caused the greatest proliferation after 24 and 48 hours. Alizarin test showed that the lowest concentrations of CH and propolis at 14 days induced the formation of calcium nodules but at 21 days, propolis was deposited on the cells and calcification was not well recognizable

Conclusion: propolis led to higher cell vitality at all concentrations in comparison to CH. However, due to its deposition on the cells, its effects on mineralization at 48 hours could not be determined

effect of propolis as a biological storage media on periodontal ligament cell survival in an avulsed tooth: an in vitro study

Both the length of extra-alveolar time and type of storage media are significant factors that can affect the long-term prognosis of replanted teeth. This study aims to compare propolis 50%, propolis 10%, Hank's balanced salt solution [HBSS], milk and egg white on periodontal ligament [PDL] cell survival for different time points. In this in vitro experimental study, we divided 60 extracted teeth without any periodontal diseases into five experimental and two control groups that consisted each experimental group with 10 and each control group with 5 teeth. The storage times were one and three hours for each media. The controls corresponded to 0-minute [positive] and 12-hour [negative] dry time. Rinsing in the experimental media, the teeth were treated with dispase and collagenase for one hour. Cell viability was determined by using trypan blue exclusion. Statistical analysis of the data was accomplished by using two-way analysis of variance [ANOVA] complemented by the Tukey's HSD post-hoc. Within one hour, there was no significant difference between the two propolis groups, however these two groups had significantly more viable PDL cells compared to the other experimental media [p<0.05]. The results of the three-hour group showed that propolis 10% was significantly better than egg white, whereas both propolis 10% and 50% were significantly better than milk [p<0.05]. Based on PDL cell viability, propolis could be recommended as a suitable biological storage media for avulsed teeth

Effect of propolis on dentin regeneration and the potential role of dental pulp stem cell in guinea pigs

Evaluation of the effect of Propolis as a bioactive material on quality of dentin and presence of dental pulp stem cells. For conducting this experimental split-mouth study, a total of 48 maxillary and mandibular incisors of male guinea pigs were randomly divided into an experimental Propolis group and a control calcium hydroxide group. Cutting the crowns and using Propolis or calcium hydroxide to cap the pulp, all of the cavities were sealed. Sections of the teeth were obtained after sacrificing 4 guinea pigs from each group on the 10th, 15th and 30th day. After they had been stained by hematoxylin and eosin [H and E], specimens underwent a histological evaluation under a light microscope for identification of the presence of odontoblast-like cells, pulp vitality, congestion, inflammation of the pulp and the presence of remnants of the material used. The immunohistochemistry [IHC] method using CD[29] and CD[146] was performed to evaluate the presence of stem cells and the results were statistically evaluated by Kruskal-Wallis, Chi Square and Fisher tests. In H and E stained specimens, there was no difference between the two groups in the presence of odontoblast-like cells, pulp vitality, congestion, inflammation of the pulp and the presence of remnants of used material[p>0.05]. There was a significant difference between the quality of regenerative dentin on the 15[th] and 30[th] days [p<0.05]: all of the Propolis cases presented tubular dentin while 14% of the calcium hydroxide cases produced porous dentin. There was no significant difference between Propolis and calcium hydroxide in stimulation of dental pulp stem cells [DPSCs]. This study which is the first one that documented the stimulation of stem cells by Propolis, provides evidence that this material has advantages over calcium hydroxide as a capping agent in vital pulp therapy. In addition to producing no pulpal inflammation, infection or necrosis this material induces the production of high quality tubular dentin

Evaluation of the distance of apical constriction from anatomic and radiographic apices in extracted maxillary second premolars using the clearing technique

Precise knowledge regarding the topography of the tooth apex and location of the apical assessing the constriction are necessary for good and efficient root canal treatment and its long term prognosis. Since radiography is among the most commonly used methods for termination point, it is essential to be able to determine the exact location of apical constriction by radiography. The aim of this study is to evaluate the distance of apical constriction from anatomic and radiographic apices in extracted maxillary second premolars using clearing technique. It also compared the reliability of radiographic results with that of histologic findings. In this in-vitro experimental study, 50 extracted maxillary second premolars of patients presenting to various dental care centers in Tehran were selected. After cleaning and disinfecting the root surfaces and preparing the access cavity, 2% methylene blue was injected into the canals along with the use of negative pressure. Then, demineralization and clearing process were done using 5% nitric acid and methyl salicylate. Samples were evaluated under stereomicroscope at X16 magnification. In order to evaluate the distance between apical constriction and radiographic apex, a #10 file was fixed at the apical constriction under the stereomicroscope. Covering the apices with sealer, radiographs were taken from all samples. The reliability of radiographic results was compared with that of histologic findings. The mean distance of apical constriction from the anatomic and radiographic apices was 0.9 and 1.05 mm, respectively. Sensitivity, specificity, positive and negative predictive values of radiographic results were 87.8%, 88.8%, 93% and 62%, respectively. The likelihood ratio for positive and negative radiographic results was 7.9 and 0.1%, respectively. The diagnostic odds ratio was 57.6% which is indicative of the acceptable accuracy and validity of the radiographic results in assessing the distance of apical constriction from the anatomic apex. This study demonstrated that the distance of apical constriction from the anatomic and radiographic apices in the maxillary second premolars was approximately 1 mm and therefore, the process of cleaning, shaping and obturation should end at this point. This study emphasizes on the accuracy of radiographic findings and importance of having sufficient anatomic knowledge for achieving a good treatment outcome in a clinical setting

Coronal sealing ability of three temporary filling materials

Providing adequate coronal seal of temporary filling materials is critical for the success of root canal therapy. The aim of this in vitro study was to compare coronal seal ability of three restorative materials over different periods of time. Ninety-eight molar teeth were selected. Once access cavities were prepared, teeth were divided randomly into three time groups [1 day, 1 week, and 4 weeks]. Each group was then subdivided into three groups of 10 teeth. Each subgroup was restored using one of three restorative materials including Coltosol, Cavizol and Zonalin and then incubated in distilled water at 37[degree]C. The samples were then immersed in 2% methylene blue dye. After rinsing and drying, teeth were sectioned longitudinally and examined for dye penetration. Kruskal-Wallis and Mann Whitney U tests were used to analyze the data. All experimented materials showed increasing leakage from the 1[st] day to the 4[th] week. Zonalin showed more leakage than Coltosol and Cavizol at each time interval [P<0.05], but there was no significant difference between Coltosol and Cavizol. Coltosol and Cavizol are suitable temporary materials for up to 1 week

Relation between pulpal neuropeptides and dental caries

Dental pulp has neural fibers that produce neuropeptides like Substance P [SP] and calcitonin gene-related peptide [CGRP]. The inflammation of dental pulp can lead to an increase amount of SP and CGRP release, especially in symptomatic irreversible pulpitis. Therefore, it can be assumed that neuropeptides have some role in the progression of inflammation of the dental pulp. The aim of this study was to determine the relation between the presence and concentration of neuropeptides in dental pulps of carious teeth caries. For this purpose, pulpal tissues were collected from 40 teeth [20 carious and 20 intact]. Pulpal samples were cultured for 72 hours. ELISA reader was used for the detection of SP and CGRP in supernatant fluids. Statistical analysis was made by Mann-Whitney U and Chi square tests. SP and CGRP were present in 65% and 20% of inflamed pulpal samples, respectively and 40% and 5% of normal pulpal samples, respectively. Level of SP was significantly higher in inflamed pulp samples compared to intact pulps; however, there was no statistical difference when the other groups and neuropeptides were compared. The mean concentration of SP in normal pulps was 3.4 times greater than that of CGRP; interestingly in inflamed pulps the concentration of SP was 22.3 times greater than CGRP. We can conclude that in inflamed dental pulps, the concentration of SP is higher than CGRP. It can be hypothesized that CGRP has less effect on the inflammatory changes of dental pulps

Antimicrobial activity of three root canal irrigants on Enterococcus faecalis: an in vitro study

The aim of this study was to compare the antimicrobial effects of 2.5% Sodium hypochlorite [NaOCl], 2% Chlorhexidine Gluconate [CHX] and BioPure MTAD [MTAD] on Enterococcus [E] faecalis-contaminated root canals of human extracted teeth. Seventy human intact extracted single-rooted teeth with straight root canal randomly divided into 5 groups: positive control [n=5], negative control [n=5], 2.5% NaOCl [n=20], 2% CHX [n=20], and MTAD [n=20]. Each tooth was instrumented using the passive step-back technique hand and rotary instruments. E. faecalis incubated into the canals and grew for 4 weeks. Canals irrigated using three mentioned solutions for 5 minutes. Samples were taken from canal walls and transferred into Brain Heart Infusion [BHI] culture medium and placed in an incubator at 37??C for 96 hours and bacteriological evaluations were done. Chi- Square test and SPSS software were used for the statistical analysis of the results. Bacterial growth was seen in only one sample of MTAD group [5%], but in 4 of CHX group [20%] and 5 of NaOCl group [25%]. Chi-Square test showed no statistically difference between groups. Based on the results of this study, it seems that all three solutions have acceptable antimicrobial effect on E. faecalis