Effect of Photobiomodulation on Pain Following Single Visit Non-surgical Root Canal Treatment of Molar Teeth with Symptomatic Irreversible Pulpitis

ABSTRACT Objective: To assess the effect of Photobiomodulation (PBM) on post-endodontic pain of mandibular molar teeth with symptomatic irreversible pulpitis. Material and Methods: In this clinical trial, mandibular molars with symptomatic irreversible pulpitis underwent primary endodontic treatment in 90 systemically healthy patients. After root canal treatment, the patients were randomly divided into two groups of PBM with diode laser at 940 nm wavelength and 200 mW output power and placebo (mock PBM therapy). Level of pain was recorded at 6, 12, 24, 48, and 72 hours postoperatively using a visual analog scale (VAS). The data were analyzed using the Mann-Whitney test and the Kruskal-Wallis test. Results: The results showed that post-endodontic pain at all time points was significantly lower in the PBM group compared with the placebo group. The pain score in the PBM group was significantly lower than the placebo group (p<0.05). However, this difference was not significant at 48 h (p=0.18) and 72 h (p=0.12) postoperatively. Also, the results showed that the mean pain score in males and females in the PBM group was significantly lower than in males and females in the placebo group. Conclusion: Photobiomodulation can effectively decrease post-endodontic pain in mandibular molar teeth with symptomatic irreversible pulpitis.

Assessment of Cytotoxicity and Odontogenic/Osteogenic Differentiation Potential of Nano-Dentine Cement Against Stem Cells from Apical Papilla.

OBJECTIVE: Assessment of the cytotoxicity of novel calcium silicate-based cement is imperative in endodontics. This experimental study aimed to assess the cytotoxicity and odontogenic/osteogenic differentiation potential of a new calcium silicate/pectin cement called Nano-dentine against stem cells from the apical papilla (SCAPs). MATERIALS AND METHODS: In this experimental study, the cement powder was synthesized by the sol-gel technique. Zirconium oxide was added as opacifier and Pectin, a plant-based polymer, and calcium chloride as the liquid to prepare the nano-based dental cement. Thirty-six root canal dentin blocks of human extracted single-canal premolars with 2 mm height, flared with #1, 2 and 3 Gates-Glidden drills were used to prepare the cement specimens. The cement, namely mineral trioxide aggregate (MTA), Biodentine, and the Nano-dentine were mixed according to the manufacturers' instructions and applied to the roots of canal dentin blocks. The cytotoxicity and odontogenic/osteogenic potential of the cement were evaluated by using SCAPs. RESULTS: SCAPs were characterized by the expression of routine mesenchymal cell markers and differentiation potential to adipocytes, osteoblasts, and chondrocytes. Cement displayed no significant differences in cytotoxicity or calcified nodules formation. Gene expression analysis showed that all three types of cement induced significant down- regulation of COLA1; however, the new cement induced significant up-regulation of RUNX2 and SPP1 compared to the control group and MTA. The new cement also induced significant up-regulation of TGFB1 and inducible nitric oxide synthase (iNOS) compared with Biodentine and MTA. CONCLUSION: The new Nano-dentin cement has higher odontogenic/osteogenic potential compared to Biodentine and MTA for differentiation of SCAPs to adipocytes, osteoblasts, and chondrocytes.

Pulp sensibility tests responses in patients with anxiety and depression.

Background: In view of the importance of pulp sensibility tests in clinical decision-making and the impact of psychological factors on test results, we evaluated in this study dental pulp responses to pulp sensibility tests (ie, cold and electric) in patients with anxiety and depression. Material and Methods: A number of 90 people age 20 to 30 participated in the study, including 30 healthy and 60 with anxiety and depression, whose disorder was approved by a psychiatrist based on the Symptom Checklist 90-R questionnaire. Pulp sensibility tests included electric and cold ones were performed on lateral mandibular teeth. The cold test results were recorded based on the visual analogue scale (VAS) pain scoring (0 no response, 10 worst pain). Electric pulp test was performed using a digital pulp tester. The lowest current that stimulated a pulp response was recorded. The data were analyzed using the Mann-Whitney and Kruskal-Wallis tests. Results: The cold test pain intensity was significantly higher in patients than in healthy subjects and was significantly associated with the severity of anxiety and depression. In addition, the electric pulp test current to evoke a response was significantly lower in patients than in healthy subjects and was also significantly associated with the severity of anxiety and depression. Conclusions: Given the limitations of this study, anxiety and depression significantly affect the results of pulp sensibility tests. Key words:Anxiety, Cold pulp test, depression, electric pulp testing.

Proliferation, odontogenic/osteogenic differentiation, and cytokine production by human stem cells of the apical papilla induced by biomaterials: a comparative study.

INTRODUCTION: Clinical applications of bioactive materials are increasing in biomedical tissue engineering. This study sought to assess the effect of calcium enriched mixture (CEM) cement, Biodentine, mineral trioxide aggregate (MTA), octacalcium phosphate (OCP), and Atlantik on proliferation, odontogenic/osteogenic differentiation, and pro-inflammatory cytokine production by human stem cells of the apical papilla (SCAPs). MATERIALS AND METHODS: Proliferation of SCAPs treated with different biomaterials was evaluated using trypan blue exclusion test and flow cytometry. Differentiation of cells was evaluated using ALP activity, alizarin red staining, and RT-PCR. The expression of genes of pro-inflammatory cytokines was also evaluated using RT-PCR. RESULTS: The SCAPs treated with biomaterials showed significantly higher proliferation, increased ALP activity, higher number of calcified nodules, and up-regulation of genes related to odontogenic/osteogenic markers compared to the control group. The expression of pro-inflammatory cytokines increased in all groups compared to the control group. CONCLUSION: The tested biomaterials could induce odontogenic/osteogenic differentiation in SCAPs. MTA had a greater potential for induction of differentiation of SCAPs to odontoblast-like cells while OCP had higher potential to induce differentiation of SCAPs to osteoblast-like cells (MTA↔ BD↔ CEM↔ Atlantik↔ OCP).

Interaction of intracanal medicaments with apical papilla stem cells: quantitative cytotoxicity assessment by methyl thiazolyl tetrazolium, trypan blue and lactate dehydrogenase.

BACKGROUND: Chemical residues often have cytotoxic effects on the stem cells. This study aimed to assess the cytotoxic effects of intracanal medicaments on stem cells of the apical papilla (SCAPs) using methyl thiazolyl tetrazolium (MTT), trypan blue exclusion (TBE) and lactate dehydrogenase release (LDHR) assays. METHODS: SCAPs were cultured and exposed to 0.125, 0.25, 1, 5 and 10 mg/mL concentrations of modified triple antibiotic paste (mTAP)/distilled water (DW), mTAP/chlorhexidine (CHX), calcium hydroxide(Ca(OH)2)/CHX and Ca(OH)2/DW. Cell viability was quantitatively analyzed using the MTT, LDHR and TBE assays. Data were analyzed using one-way ANOVA and Tukey's test. RESULTS: All three assessment methods yielded the same results. Ca(OH)2/ DW resulted in the highest and mTAP/CHX resulted in the lowest cell viability. In contrast to Ca(OH)2, mTAP decreased cell viability in a dose-dependent manner. Also, addition of CHX to mTAP and Ca(OH)2 increased their cytotoxicity. CONCLUSIONS: In contrast to the proliferative effects of Ca(OH)2, even low concentrations of mTAP have cytotoxic effects on SCAPs.

Difference between the Actual and Labeled Concentrations of Several Domestic Brands of Sodium Hypochlorite.

Introduction: Sodium hypochlorite (NaOCl) is extensively used in root canal treatment and its efficacy depends on the concentration of free available chlorine (FAC). This study aimed to assess the chlorine content of 10 domestically manufactured household bleach products available in the Iranian market and evaluate the effect of temperature, time and daily bottle uncapping on FAC concentration and pH of these products. Methods and Materials: One-liter bottles of 10 available brands of household bleach (n=4 of each brand) were collected and randomly divided into four groups (n=10). Two groups were refrigerated at 4°C while the remaining two were stored at room temperature. One group of refrigerated and one group of room temperature samples were subjected to daily bottle uncapping followed by agitation and recapping for 3 months (six times a week to simulate weekly office work). The remaining bottles remained untouched and served as controls. The concentration of FAC in each sample was measured using the iodometric titration assay, and the pH was measured using a calibrated pH-meter at baseline and 1, 2 and 3 months. The results were analyzed using the one-way ANOVA and t-test. Results: The mean concentration of FAC in the solutions was 4.87±0.19% at baseline. The measured concentration of sodium hypochlorite was different from the labeled value. The concentration of FAC decreased over time in all samples; the greatest reduction occurred in room temperature samples subjected to daily uncapping while the smallest reduction occurred in refrigerated, capped bottles (19% and 1.9%, respectively). The pH of all products decreased over time. The mean reduction in pH was 1.1 for the samples stored at room temperature for 3 months and 0.8 for the refrigerated samples. Conclusion: This in vitro study showed that the expected concentration of sodium hypochlorite solution made of household bleach for endodontic purposes is different from its actual concentration.

Endodontic and Surgical Management of Iatrogenic Root Injury Caused by Orthodontic Miniscrew Placement: A Case Report.

One of the potential serious complications, associated with the inter-radicular placement of an orthodontic miniscrew, is root injury. This article reports the endodontic and surgical treatments of an iatrogenic root perforation in a mandibular first molar caused by the placement of an orthodontic miniscrew anchorage. The 24-month follow-up showed a successful treatment outcome.

Comparative Evaluation of Root Canal Transportation by Three NiTi Single-File Systems in Curved Canals: A Cone Beam Computed Tomography Study.

INTRODUCTION: This study is aimed at evaluating root canal transportation in the mesiobuccal canal of mandibular first molars prepared with One Shape, Reciproc, and M-One nickel titanium (NiTi) single-file rotary systems using cone beam computed tomography (CBCT). MATERIALS AND METHODS: In this ex vivo study, CBCT scans of 45 extracted human mandibular first molars with 20-40° curvature were obtained. The teeth were randomly divided into three groups (n=15) for preparation of the mesiobuccal canal with One Shape, Reciproc, and M-One rotary systems according to the manufacturers' instructions. CBCT scans were obtained again after canal preparation. Changes caused by preparation in the coronal, middle, and apical thirds were determined on CBCT scans and analyzed using the Kruskal-Wallis test at P ≤ 0.05 level of significance. RESULTS: No significant difference was noted in the amount of canal transportation among the three groups (P > 0.05). M-One caused greater transportation in the apical third compared with Reciproc and One Shape, and One Shape caused greater transportation in the coronal third compared with other groups, although its magnitude was less than 0.3 mm. CONCLUSION: Reciproc, One Shape, and M-One are not significantly different in terms of canal transportation.

Arg753gln and Arg677 Trp Polymorphisms of Toll-Like Receptor 2 In Acute Apical Abscess.

STATEMENT OF THE PROBLEM: Genetic polymorphisms can alter immunity response against pathogens, which in turn influence individuals' susceptibility to certain infections. PURPOSE: Our aim was to determine the association of Arg753Gln (rs5743708) and Arg677Trp (rs12191786) polymorphisms of toll like receptor-2 gene with the two clinical forms of apical periodontitis: acute apical abscess (AAA) and asymptomatic apical periodontitis (AAP). MATERIALS AND METHOD: There were 50 patients with AAA as case group and 50 with AAP as control group. Genotyping was done using Tetra-ARMS (amplification refractory mutation system) PCR. RESULTS: Heterozygous genotype of Arg677Trp polymorphism was associated with risk of AAA (OR=1.9, 95% CI: 0.7-5.5, p= 0.05). Although statistically insignificant, Arg677Trp polymorphism promoted the risk of AAA in dominant model (OR=2.1, 95% CI: 0.7-5.9, p> 0.05). The frequency of mutant allele (T) of Arg677Trp polymorphism was higher in AAA (14%) than AAP (7%) subjects (OR=1.7, 95% CI: 0.6-4.7). For Arg753Gln polymorphism, wild homozygous (GG) represented the dominant genotype in both cases (96%) and controls (100%). Variant allele (A) of Arg753Gln polymorphism was identified in 2% of AAA, while no individual represented with this allele in AAP subjects. Individuals with Arg753Gln; Arg677Trp (GG; TC) combination showed an elevated risk of AAA (OR=1.6, 95% CI: 0.5- 4.2, p> 0.05). CONCLUSION: Arg677Trp polymorphism of TLR-2 rendered a higher risk for the development of abscesses in apical periodontitis. It is recommended to explore role of this polymorphism in other populations.

Role of Thr399Ile and Asp299Gly polymorphisms of toll-like receptor-4 gene in acute dental abscess.

BACKGROUND: Apical Periodontitis (AP) is an inflammatory disease that affects the tissues surrounding the root end of a tooth. The disease which is caused by endodontic infections presents in different clinical ways including development of an acute abscess. Recent studies have provided information suggesting role of a multitude of factors in pathogenesis of acute apical abscess (AAA). In this case-control study, our goal was to evaluate the frequency and potential role of two common polymorphisms of toll like receptor-4 (TLR-4) gene; Thr399Ile (1196 C>T) and Asp299Gly (+896 A>G), in 50 patients with AAA as cases and 50 patients with asymptomatic apical periodontitis (AAP) as controls. MATERIAL AND METHODS: Saliva sample containing mucosal epithelial cells was used for DNA extraction. Polymorphisms were detected by Tetra-ARMS (Amplification Refractory Mutation System) PCR method. Statistical analyses were carried out in SPSS 21 software. RESULTS: Homozygous wild type (CC) and heterozygous (CT) genotypes of Thr399Ile polymorphism were detected in 84% and 16% of AAA patients respectively. In controls, respective ratios were 94% (CC) and 6% (CT). Observed difference was not statistically significant (P>0.05) for distribution of these genotypes. The mutant homozygous (TT) genotype of this polymorphism was identified in neither of the participants. Overall, T allele frequency was obtained 8% in AAA and 3% in AAP (OR=2.6, 95% CI; 0. 6-10.6, p>0.05). For Asp299Gly polymorphism, no individual was detected with the mutant allele in case or control groups. CONCLUSIONS: Our results indicated a possible role for Thr399Ile polymorphism in acute presentations of abscess in AAA. However, the impact of this polymorphism needs to be more assessed in future studies. Key words:Genetic polymorphism, periapical abscess, periapical periodontitis, toll-like receptor 4.

Evaluation of Cytotoxic Effects of Various Endodontic Irrigation Solutions on the Survival of Stem Cell of Human Apical Papilla.

INTRODUCTION: Root canal disinfection is an important step in regenerative endodontic treatments. An ideal irrigating solution must have high antimicrobial activity and minimum cytotoxicity. This study sought to assess the effect of some irrigating solutions on stem cells from the human apical papilla (SCAP) after different periods of exposure. METHODS AND MATERIALS: Stem cells were isolated from immature, impacted mandibular third molars, transferred to 24-well plates, randomly divided into 6 experimental groups and exposed to BioPure MTAD Cleanser, QMix, 17% EDTA, 2% chlorhexidine (CHX), 5.25% sodium hypochlorite (NaOCl), sterile saline and untreated control group. Cytotoxicity of these solutions was assessed after 1, 5 and 15 min of exposure using the methyl thiazol tetrazolium (MTT) assay. Data were statistically analyzed using repeated measures ANOVA. Level of significance was set at 0.05. RESULTS: The mean percentage of viable cells in all experimental groups was significantly different from the control and sterile saline groups at all the time points (P<0.0001). The mean percentage of viable cells significantly decreased over time in NaOCl, QMix, EDTA and MTAD groups, but no significant reduction was noted in CHX group. At all the time points the highest and the lowest cytotoxicity were seen in MTAD and normal saline groups, respectively. Cytotoxicity of the understudy materials from the highest to the lowest was as follows: MTAD>EDTA>QMax=NaOCl>CHX> sterile saline. CONCLUSION: Chlorhexidine had the lowest cytotoxicity compared to EDTA, MTAD, QMix and NaOCl and its cytotoxicity did not change over time compared to other solutions.

Antifungal Efficacy of Green Tea Extract against Candida Albicans Biofilm on Tooth Substrate.

OBJECTIVES: Biomechanical preparation and irrigation with antimicrobial solutions are necessary to disinfect the root canal space. This in vitro study aimed to examine the antifungal effect of green tea extract on Candida albicans biofilm formed on tooth substrate. MATERIALS AND METHODS: Minimum fungicidal concentration (MFC) and minimum inhibitory concentration at which 90% of the isolates were inhibited (MIC90) were studied using green tea extract and sodium hypochlorite with the broth macro-dilution method. Then, anti-candida effects of this extract were tested on tooth substrates of 45 extracted single-canal premolar teeth. After biomechanical cleaning of the root canals, the teeth were sectioned vertically and randomly divided into three groups of 30. All the samples were infected with C. albicans (PTCC 5027) and exposed to the test solutions (sodium hypochlorite, green tea, normal saline) for five, 10 and 15 minutes. Data analyses of the samples were performed using two-way ANOVA. RESULTS: The average number of microorganisms showed a significant decrease after five, 10 and 15 minutes of exposure to green tea extract and sodium hypochlorite. The average number of C. albicans in green tea extract and sodium hypochlorite groups decreased to 1/3 and 1/2 of the initial values, respectively. CONCLUSION: Antifungal activity of green tea extract was time-dependent and its inhibitory action did not decrease significantly over time. It is recommended to consider other properties of green tea such as tissue solubility, impact on dentin structure and use as an intracanal medicament or for smear layer removal in the clinical setting.

The Efficacy of FlexMaster's IntroFile, PreRaCe and Gates Glidden Drills in Straight-Line Access: A CBCT Assessment.

INTRODUCTION: An overlooked but important part of successful root canal treatment is a straight-line access (SLA). The purpose of this in vitro study was to compare the efficacy of IntroFile and PreRaCe rotary instruments with Gates Glidden (GG) drills in gaining SLA by cone-beam computed tomography (CBCT). METHODS AND MATERIALS: A total of forty five extracted mandibular first molars were selected and mounted in dental like arches. Subsequently, they were randomly classified into three groups (n=15). After preparation of a standard access cavity, orifices of the mesiobuccal canal was reached and a #10 file was inserted to explore the canals until the file tip was visible at the apex. Then, preoperative CBCT images were taken. SLA was gained in three groups; group 1, FlexMaster's IntroFile (FM); group 2, PreRaCe (RC) and group 3, GG. Again, the first binding file at the working length (WL) was placed in the canal and postoperative CBCT images in similar positions were taken. The pre/post operative morphology of the canal was evaluated for changes. Data was analyzed using the one-way ANOVA and post-hoc Bonferroni analysis. RESULTS: The average amount of reduction in coronal canal curvature in FM, RC and GG groups was 2.43±1.79, 3.17±2.05 and 8.7±3.45, respectively. This descending trend was statistically significant. The difference between pre/post SLA changes in FM and RC groups was significant compared to GG group, while there were no significant differences between RC and FM. CONCLUSION: GG drills produced extraordinary results in reducing coronal curvature of the canal and achieving SLA. They are also more effective than nickel-titanium (NiTi) rotary instruments in canals with coronal curvature.

Evaluation of the effect of tooth type and canal configuration on crown size in mandibular premolars by cone-beam computed tomography.

INTRODUCTION: To achieve success in treatment, one cannot ignore the knowledge of pulp anatomy. Mandibular premolars are considered to be the most difficult teeth for endodontic therapy due to high variability in their canal morphology. It is possible that a relation exists between the crown size and the number of extra canals in these teeth, so this in vitro study aims to investigate the relationship between the crown size and the uncommon morphology of mandibular premolars using Cone-Beam Computed Tomography (CBCT). MATERIALS AND METHODS: Eighty three extracted mandibular human premolars were exposed to radiation using the CBCT device. Root canal configuration was categorized according to the Vertucci's classification. The crown size was measured in three axial, coronal and sagittal sections. Finally, the relation between these two factors was evaluated with variance analysis (two-way ANOVA) and chi-square. RESULTS: The most common canal type in the mandibular first and second premolars are type I (71% and 76%, respectively), followed by type V (29% and 22%, respectively). No significant relationship was found between the crown size and extra canals in mandibular premolars (P>0.05). CONCLUSION: In this in vitro study, the average crown size in two-canalled second premolars was less than that in first premolars with a single canal; although the difference was not statistically significant. The research hypothesis was therefore rejected in both first and second mandibular premolars.