Prevalence of House Dust Mites and Presence of Der p 1 and Der f 1 in Ordu, Giresun, Trabzon and Rize Provinces.

OBJECTIVE: This study was carried out to detect house dust mites in houses and to investigate group 1 antigens of Dermatophagoid species in Ordu, Giresun, Trabzon and Rize provinces of the Central and Eastern Black Sea Region. METHODS: Dust samples obtained from the beds were subjected to both microscopic and antigenic examination. Samples prepared by the lactic acid method for microscopic examination were evaluated under a light microscope. Antigenic analysis was performed by investigating Der p 1 and Der f 1 belonging to D. pteronyssinus and D. farinae by ELISA test. RESULTS: 90.3% of the dust samples were evaluated positive by microscopic examination (10x, 40x) and 149 mites were detected. D. pteronyssinus 74%, D. farinae 13%, Dermatophagoides spp. growth forms 5%, Cheyletus spp. 1%, E. maynei 1%, C. arcuatus 1%, T. putrescentiae 1%, L. destructor 1% and unidentified mites were detected at the rate of 3% respectively. Der p 1 antigen was detected in 93% and Der f 1 antigen in 84.7%. The highest amount of antigen detected in one gram of powder was 1,272 µg for Der p 1 and 0,482 µg for Der f 1. CONCLUSION: No difference was observed between mite species and distribution in the provinces where the study was conducted (p<0.05). Dermatophagoides were found in 93% of the population. The low (4%) rate of storage/food mites is related to the fact that samples were not taken from the floors. Antigen accumulation may be important in the beds since the activity of the mites is observed throughout the year in temperate and humid regions. It is thought that this diagnosis method can be used and can be taken into account in terms of the environments in which sensitive people live.

Cryptococcal meningitis in a non-HIV patient with solid organ transplantation.

Cryptococcal meningitis (CM) is often associated with human immunodeficiency virus (HIV). Recently, this microorganism has been increasingly identified in HIV-negative patients. CM cases are encountered in HIV-negative individuals, especially secondary to liver disease, solid organ transplantation (SOT), tuberculosis, lymphoproliferative diseases with T-cell-mediated immunological disorders, long-term corticosteroid use, malignancies, diabetes mellitus, and sarcoidosis. Our patient is an HIV-negative, SOT case with CM. It should be considered that CM can also occur in HIV-negative patients. As in our case, patients receiving long-term immunosuppressive therapy should be evaluated for CM, and renal functions should be closely monitored during treatment. There is a need for more case reports on the subject, especially in CM detected HIV-negative patients, due to the different treatment protocols and challenging clinical conditions compared to HIV-positive cases.

The BDNF-TrkB signaling pathway is partially involved in the neuroprotective effects of hydrogen sulfide in Parkinson's disease.

Recent studies have demonstrated that hydrogen sulfide (H2S) has a neuroprotective effect in neurodegenerative diseases. It is possible that this effect is supported by brain-derived neurotrophic factor (BDNF). Our aim is to examine the effects of H2S on neural damage in Parkinson's disease (PD) and to reveal the role of the BDNF-TrkB pathway in its possible effect. PD model was created with 1-methyl-phenyl-1,2,3,6-tetrahydropyridine (MPTP). C57BL/6 breed male mice were randomly divided into six groups: control, K252a, MPTP, MPTP + K252a, MPTP + NaHS, and MPTP + NaHS + K252a. TrkB receptor antagonist K252a and sodium hydrosulfide (NaHS) as a H2S donor were administered intraperitoneally. An increase was observed in the motor behavior tests in MPTP group, but NaHS treatment shortened the time spent on the balance beam and pole tests. It was also noticed that the BDNF-pathway played a role in the shortening of this period. Mice that received NaHS were found to have less MPTP-induced cellular damage. A positive effect of BDNF was also detected in the protection of these neurons. BDNF levels in the SN were significantly increased in MPTP group, compared to control group. Tissue CBS levels decreased in the groups that received K252a, compared to MPTP group. The findings of the present study display that the BDNF-TrkB pathway partially plays a role in the protective effect of H2S in the experimental mouse model of PD. This effect is probably due to changes in intracellular signaling pathways, rather than TrkB receptor expression.

The Investigation of the Prevalance and Epidemiology of House Dust Mites in Giresun

Objective: The aim of this study was to determine the species of house dust mites and their prevalence in Giresun. Methods: Dust samples taken from 15 houses which were visited monthly for one year were examined by the lactic acid method. Results: A total of 2251 mites were detected in the study. The distribution of mites was as follows: 81.8% Dermatophagoides pteronyssinus, 0.5% Dermatophagoides farinae, 0.04% Euroglypus maynei (E. maynei), 4.2% Dermatophagoides spp. 0.06% A. siro, 2.4% Glycphagus domesticus, 0.9 % Lepidoglyphus destructor, 1.4% Tyrophagus putrescentiae, 4.5% Campunatus arcuatus, 1.3% Cheyletus spp. Pyroglyphid species were detected in all houses (100%). Dermatophagoides pteronyssinus was found in 100%, D. farinae 5% and E. maynei 4% of the houses. Conclusion: The mites in Giresun were found in all houses throughout the year and were detected in all of the samples. Although they were detected in greater amounts in the spring and summer, only a moderate relationship could be detected with temperature. In August-October period, mite existence was significantly higher than the January-March period (p<0,05). D. pteronyssinus was found in higher numbers on the mezzanine floors between May and August and on the ground floors in September and October (p<0,05). We think that the climate characteristics of Giresun are suitable for the development and proliferation of house dust mites and this can pose a risk for sensitive people.

The Prevalence of Mixed Genotype Infections in Turkish Patients with Hepatitis C: a Multicentered Assessment.

BACKGROUND: HCV virus infections are one of the major health problems in the world that can cause cirrhosis and liver cancer at a higher rate than other hepatitis data. The aim of this study was to determine the prevalence of mixed infections with different HCV genotypes in Turkey and also to evaluate the current HCV genotype and sub-type distributions by a multicentered assessment. METHODS: The HCV genotype data of 17,578 hepatitis C patients collected from 23 centers from different geographic regions covering all Turkey were collected. The data included information about the HCV genotypes in the last 10 years (between 2007 and 2016), demographic properties of the patients and the methods/systems used to determine the genotypes. RESULTS: Two hundred twenty-eight of the patients (1.3%) had mixed genotype. The most common mixed genotype combination was 1b + 4 (0.83%) followed by 1a + 1b (0.26%). Genotype distribution varies according to geographical regions. However, genotype 1 (82.92%) was the most common genotype in all regions and all years. This was followed by genotype 3 (7.07%) and genotype 4 (5.43%). A variety of methods were used by the centers including sequencing, pyrosequencing, real-time PCR, in-house RFLP, reverse hybridization (LIPA), and hybridization. CONCLUSIONS: Infection with mixed HCV genotypes in Turkey is uncommon. Genotype distribution varies according to geographic regions; the most common genotype 1 is encountered all over the country, while genotypes 3 and 4 are only in some of the centers. Since there is limited information about mixed HCV infection, further investigations are needed to determine the clinical importance of mixed HCV infection.

Fracture Resistance of Teeth with Simulated Perforating Internal Resorption Cavities Repaired with Different Calcium Silicate-based Cements and Backfilling Materials.

INTRODUCTION: This study assessed the fracture resistance (FR) of teeth with simulated perforating internal resorption cavities repaired with different calcium silicate-based cements (CSCs) and backfilling materials. METHODS: Ninety-six mandibular premolar teeth were used. Twelve of the teeth were assigned as negative control group. Remaining roots were instrumented with rotary files, and standardized internal resorption cavities were prepared on the middle half of roots with burs. Twelve of the samples were not further interfered and were assigned as a positive control group. The apical 4 mm of the remaining 72 root canals was obturated with single-cone technique and divided into 6 groups according to CSCs used for repairing of cavities and backfilling materials as follows: MTA + MTA, MTA + gutta-percha/sealer, Biodentine + Biodentine, Biodentine + gutta-percha/sealer, MTA Plus + MTA Plus, and MTA Plus + gutta-percha/sealer. Specimens were embedded in acrylic resin and then subjected to fracture testing. The forces when the fracture occurred were analyzed with analysis of variance and Bonferroni tests at P = .05. RESULTS: No significant difference was found among CSCs irrespective of backfilling materials (P > .05). Groups MTA + gutta-percha/sealer, Biodentine + gutta-percha/sealer, and MTA Plus + gutta-percha/sealer showed significantly lower FR compared with groups MTA + MTA, Biodentine + Biodentine, and MTA Plus + MTA Plus, respectively (P < .05). The highest FR was observed in group Biodentine + Biodentine, and the lowest was in group MTA Plus + gutta-percha/sealer. FR of positive control group was statistically lower than groups completely filled with CSCs (P < .05), whereas FR of negative control group was statistically higher than the groups combined with gutta-percha and sealer (P < .05). CONCLUSIONS: The backfilling with CSCs may be a preferable material rather than gutta-percha/sealer combination for the roots with perforated internal resorptions.

Mineral content analysis of root canal dentin using laser-induced breakdown spectroscopy.

OBJECTIVES: This study aimed to introduce the use of laser-induced breakdown spectroscopy (LIBS) for evaluation of the mineral content of root canal dentin, and to assess whether a correlation exists between LIBS and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS) methods by comparing the effects of irrigation solutions on the mineral content change of root canal dentin. MATERIALS AND METHODS: Forty teeth with a single root canal were decoronated and longitudinally sectioned to expose the canals. The root halves were divided into 4 groups (n = 10) according to the solution applied: group NaOCl, 5.25% sodium hypochlorite (NaOCl) for 1 hour; group EDTA, 17% ethylenediaminetetraacetic acid (EDTA) for 2 minutes; group NaOCl+EDTA, 5.25% NaOCl for 1 hour and 17% EDTA for 2 minutes; a control group. Each root half belonging to the same root was evaluated for mineral content with either LIBS or SEM/EDS methods. The data were analyzed statistically. RESULTS: In groups NaOCl and NaOCl+EDTA, the calcium (Ca)/phosphorus (P) ratio decreased while the sodium (Na) level increased compared with the other groups (p < 0.05). The magnesium (Mg) level changes were not significant among the groups. A significant positive correlation was found between the results of LIBS and SEM/EDS analyses (r = 0.84, p < 0.001). CONCLUSIONS: Treatment with NaOCl for 1 hour altered the mineral content of dentin, while EDTA application for 2 minutes had no effect on the elemental composition. The LIBS method proved to be reliable while providing data for the elemental composition of root canal dentin.

Fracture resistance of simulated immature teeth after internal bleaching procedures.

The aim of this study was to evaluate the fracture resistance of simulated immature teeth after internal bleaching. The teeth were assigned as follows (n = 12/group); Group-1: The pulp chamber was filled with ProRootMTA and bleached intracoronally with sodium perborate mixed with 37% carbamide peroxide gel; Group-2: The pulp chamber was filled with ProRootMTA without bleaching; Group-3: The pulp chamber was filled with Biodentine and bleached intracoronally as Group-1; Group-4: The pulp chamber was filled with Biodentine without bleaching; and Group-5: Teeth received no intervention (control). The specimens were loaded vertically until root fracture occurred. The data were analysed with Kruskal-Wallis and Dunn tests. There was no significant difference between the fracture resistances of the experimental groups (P > 0.05). However, all experimental groups had significantly lower fracture resistance than the control group (P < 0.05). Neither the tested calcium silicate cements nor the bleaching procedures had a significant impact on fracture resistance values.

Effect of Low-surface Tension EDTA Solutions on the Bond Strength of Resin-based Sealer to Young and Old Root Canal Dentin.

INTRODUCTION: The purpose of this study was to evaluate the effect of low-surface tension EDTA solutions on the push-out bond strength of resin-based sealer to young and old root canal dentin. METHODS: Root canals from 64 (n = 32 age <30 years old and n = 32 >60 years old) extracted, decoronized, single-rooted human teeth were prepared with ProTaper rotary instruments (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4 using 3 mL 2.5% sodium hypochlorite (NaOCl) between each file. Each group was divided into 4 subgroups as follows: 3 mL EDTA, REDTA (17% EDTA + 0.84 g cetyltrimethylammonium bromide; Sigma-Aldrich, St Louis, MO), EDTA-T (17% EDTA + 1.25% sodium lauryl ether sulfate, Sigma-Aldrich), and saline as the control (n = 8). The final irrigation was completed with 3 mL saline after 3 mL NaOCl in the experimental groups and 3 mL saline in the control group. After root canal filling with gutta-percha (GP) cones/AH Plus sealer (Dentsply, Petropolis, RJ, Brazil), samples were stored at 37°C and 100% humidity for 2 weeks. One-millimeter-thick horizontal sections from the coronal and midthirds of each root were sliced, and push-out bond strength values were measured using a universal testing machine. Data were analyzed using 2-way analysis of variance followed by the Bonferroni test (P < .05). RESULTS: EDTA-T, REDTA, and EDTA significantly increased the bond strength values of GP/AH Plus to the root canal dentin compared with saline in both young and old groups (P < .05). EDTA-T treatment provided higher bond strength values in young dentin compared with EDTA and EDTA-T-treated old dentin (P < .05). CONCLUSIONS: The bond strength values of GP/AH Plus could be altered depending on age and the type of EDTA compounds.

Evaluation of dentinal tubule penetration depth and push-out bond strength of AH 26, BioRoot RCS, and MTA Plus root canal sealers in presence or absence of smear layer.

Background. This study compared the effect of smear layer on the penetration depth and push-out bond strength of various root canal sealers. Methods. A total of 90 extracted human mandibular premolars were assigned into 2 groups: smear layer preserved and smear layer removed. Then the roots were further divided into 3 subgroups according to the sealer tested: AH 26, BioRoot RCS and MTA Plus. Obturation was performed with gutta-percha and the relevant sealer was mixed with 0.1% rhodamine B. Three 1-mm-thick slices were obtained from the mid-third area of each root. Two slices were selected for the push-out test and the remaining slice was used to calculate the dentinal tubule penetration depth and percentage. Results. The retention of MTA Plus and BioRoot RCS was higher than that of AH 26 when the smear layer was preserved (P<0.05). BioRoot RCS showed the lowest penetration depth when the smear layer was removed (P<0.05). Conclusion. Dentinal tubule penetration of root canal sealers had a limited effect on their adhesion to root canal wall.

Interaction of backfilling techniques and MTA plugs with additives: Fracture strength and adaptation analyses.

The aims were to evaluate the effects of different additives on the adaptation of mineral trioxide aggregate (MTA) plugs before and after different backfilling techniques and analyze the interference of filling procedures on the fracture resistance of simulated immature teeth. The apical parts of 60 teeth were filled with MTA mixed with distilled water (DW), propylene glycol (PG) or calcium chloride (CaCl2) and backfilled with cold lateral condensation (CLC) or warm vertical compaction (WVC). The specimens were subjected to adaptation analysis and fracture testing. CaCl2 addition resulted in poor marginal adaptation, while PG addition significantly decreased the fracture values (p<0.05). WVC technique negatively affected the marginal adaptation of MTA-CaCl2 plugs and decreased the fracture values of teeth with MTA-PG plugs (p<0.05). Mixing MTA with DW can be recommended as apical plug when the remaining root canal space is going to be filled with either CLC or WVC techniques.

Clinical and Epidemiological Features of Paederus Dermatitis Among Nut Farm Workers in Turkey.

Paederus dermatitis is an acute irritant dermatitis resulting from contact with the hemolymph of Paederus beetles. This dermatitis mimics other infectious skin disorders, often resulting in diagnostic dilemmas. This study of 46 patients was conducted to increase awareness about Paederus dermatitis. Possible causes of a number of cases of Paederus dermatitis in Giresun, Turkey, were investigated using climate data and telephone interviews with the patients about risk factors. Insects caught by patients were identified at the species level. All patients were hazelnut farm workers and admitted to the hospital in the months during which the hazelnut harvesting occurs. Of the patients, 11 (23.91%) presented with painful and burning skin lesions, and 35 (70.09%) complained of itching. The neck was the most involved site (47.83%). The predominant type of lesion was erythematous plaque (84.78%). No pathological findings were detected by laboratory testing. Patients reported coming into contact with the insect during the daytime. Captured insects were identified as Paederus fuscipes. Although the weather and climate were optimal for P. fuscipes during June-October, patients were admitted to the hospital only during the hazelnut harvesting season (August-September). The only risk factor identified among patients was occupation; hence we believe our study is the first to suggest that Paederus dermatitis is an occupational disease among hazelnut farm workers. We suggest that Paederus spp. may become a substantial threat due to global warming, especially among farm workers. Paederus dermatitis is not included in classic medical textbooks. It is necessary to increase awareness about this condition.

Impact of different file systems on the amount of apically extruded debris during endodontic retreatment.

OBJECTIVE: The goal of present study was to determine the effect of different nickel-titanium file systems on the amount of apically extruded debris during endodontic retreatment: D-RaCe retreatment systems, EdgeFile XR retreatment rotary files, and Reciproc R40. MATERIALS AND METHODS: Thirty-six single-rooted prepared mandibular premolar teeth were filled with Gutta-percha and AH Plus sealer. The teeth were then randomly assigned into three groups (n = 12) for retreatment. The endodontic retreatment was performed as follows: D-RaCe, EdgeFile XR, Reciproc 40. Debris extruded apically during the retreatment was collected into preweighed Eppendorf tubes. An incubator was used to store tubes at 70(°) C for 5 days. The initial weight was subtracted from final weight of the Eppendorf tubes to calculate the weight of the dry extruded debris for each group. The data obtained were evaluated using Welch analysis of variance and Games-Howell post-hoc tests (P < 0.05). RESULTS: All files resulted in apical extrusion of debris. Reciproc caused significantly less debris extrusion compared to D-RaCe and EdgeFile XR (P < 0.05). CONCLUSIONS: The findings revealed that during endodontic retreatment, number, and taper of files might have an influence on the amount of apically extruded debris during endodontic retreatment.

Final Irrigation Regimens Affect Fracture Resistance Values of Root-filled Teeth.

INTRODUCTION: The purpose of this study was to compare the effect of different final irrigation solutions on fracture resistance values (FRVs) of endodontically treated teeth. METHODS: Eighty extracted decoronated human incisors were used. Ten randomly selected roots were used as the negative control group. The remaining roots were prepared by the ProTaper system (Dentsply Maillefer, Ballaigues, Switzerland) up to F2. Ten prepared roots were selected as the positive control. The other prepared roots were divided into 6 (n = 10) groups according to the final irrigation solution used: 5 mL saline, 17% EDTA, EDTA with a surfactant (REDTA), chlorhexidine, QMix (Dentsply Tulsa Dental Specialties, Tulsa, OK), and BioPure MTAD (Dentsply Tulsa Dental Specialties). In all groups, the final irrigation was performed for 1 minute except for the BioPure MTAD group; in this group, it was applied for 5 minutes according to the manufacturer's instructions. The specimens were filled with a single gutta-percha cone and AH 26 sealer (Dentsply, De Trey, Konstanz, Germany). After being stored under 37 °C and 100% humidity for a week, the specimens were loaded in a vertical direction at 1 mm/min speed until they were vertically fractured. The results were analyzed by the Kruskal-Wallis and Siegel Castellan tests. RESULTS: The negative control group showed the highest FRV. There were statistically significant differences between the negative and positive control groups (P < .05). Specimens irrigated with REDTA and QMix showed a higher FRV compared with the positive control group (P < .05). Specimens exposed to chlorhexidine and BioPure MTAD showed a lower FRV compared with the negative control group (P < .05). CONCLUSIONS: Root canal preparation weakens the tooth. The final irrigation regimen has an impact on the FRV. A short time exposure to irrigation solutions (REDTA and QMix) that include surfactants probably contributed to the higher FRV, instead of a long time exposure as done with BioPure MTAD.

Efficacy of Combined Use of Different Nickel-Titanium Files on Removing Root Canal Filling Materials.

INTRODUCTION: The aim of this study was to estimate the remaining amount of residual filling materials in root canals after retreatment using ProTaper Universal Retreatment (PTUR) files (Dentsply Maillefer, Ballaigues, Switzerland) alone or with the additional use of the Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel), Reciproc (VDW, Munich, Germany), or Hedström-files (H-file; VDW, Antaeos, Munich, Germany) with volumetric estimation using the stereologic method via cone-beam computed tomographic images. METHODS: Forty-eight mandibular premolars with single canals were used. The canals were instrumented with ProTaper rotary instruments up to F4 and filled with gutta-percha and AH26 sealer (Dentsply De Trey, Johnson City, TN). All the samples were placed into the silicone models. Samples were scanned with cone-beam computed tomographic imaging and assigned into 4 groups (n = 12) according to retreatment files: the PTUR system group, the PTUR system plus SAF group, the PTUR system plus Reciproc group, and the PTUR system plus H-file group. The specimens were rescanned after retreatment procedures, and the volume estimations of the remaining filling materials were performed using the stereologic method. Data were analyzed using Kruskal-Wallis and Dunn tests. RESULTS: There was no significant difference among the groups regarding mean percentage volumes of the filling materials before retreatment procedures (P > .05). None of the retreatment procedures provided complete removal of the filling materials. The additional use of the SAF did not significantly improve the removal of filling materials when compared with the PTUR system alone (P > .05). However, the additional use of Reciproc or hand H-files significantly improved the removal of filling materials when compared with the PTUR system alone (P < .05). CONCLUSIONS: The additional use of files with different motion kinetics improved the removal of root canal fillings; however, none of the systems completely removed the root canal filling material from the root canals.

Radiological, stereological, and microscopic evaluation of the quality of canal fillings in oval-shaped root canals prepared with self-adjusting file.

The aim of this study was to evaluate the quality of the canal fillings performed by thermoplastic technique (Herofill) and cold lateral condensation (CLC) techniques in oval shaped canals following self-adjusting file (SAF) preparation using radiological, stereological, and microscopic evaluation methods. Twelve pairs of oval-shaped root canals were prepared with SAF and filled using CLC (n = 12) or the Herofill system (n = 12). The quality of the root canal filling was evaluated by (i) scoring bidirectional storage phosphor plate images, (ii) stereological (volumetric) analysis of cone beam computerized tomography (CBCT) images, and (iii) microscopic analysis of the cross-sectioned area of the canal and gutta-percha via image analysis software. Chi-square test, t-test, and Mann-Whitney U-tests were used respectively (p < 0.05) for the aforementioned evaluations. 58.33% of the fillings (total n = 24) that were found to be sufficient in a bucco-lingual (BL) projection were considered insufficient in the mesio-distal (MD) projection according to radiological scoring. The difference in the findings between the two types of projections (BL and MD) was significant (p < 0.05). The results of the stereological evaluation of CBCT images and image analysis of cross-sections showed no statistically significant difference between the CLC and Herofill (p > 0.05). Herofill was not superior to cold lateral compaction. Stereology can be used to obtain unbiased information about the volume of root canal fillings. Both filling techniques failed to achieve the desirable goal of 0% empty volume in all of the cases and all evaluation systems confirmed this result. SCANNING 38:427-433, 2016. © 2015 Wiley Periodicals, Inc.

Effect of powder-to-water ratio on the push-out bond strength of white mineral trioxide aggregate.

AIM: To evaluate the effect of powder-to-water ratio on the retention characteristics of white mineral trioxide aggregate (MTA; Angelus, Londrina, Pr, Brazil) over time. METHODS: One hundred and thirty-five root dentin slices from extracted single-rooted human mandibular premolar teeth were instrumented to achieve a diameter of 1.3 mm. Three MTA groups were prepared using 4:1, 3:1, and 2:1 powder-to-water ratios. The samples were stored for 96 h and 7 and 28 days at 37°C. The push-out bond strengths were measured using an Instron testing machine. Data were analyzed using two-way analysis of variance (anova) with Bonferroni correction. RESULTS: There was a statistically significant difference between the experimental groups at the 96-h and 7-day study periods (P = 0.002). At 96 h, the materials prepared at 2:1 ratio had the lowest bond strength than the samples prepared at the other two ratios (P < 0.001). There was a significant difference between the findings at 96-h and 28-day study periods for 2:1 and 4:1 ratios. The highest bond strength value was found at 28 days of exposure (P < 0.001). CONCLUSION: The powder-to-water ratio significantly interfered with the bond strength properties of white MTA.

Influence of a glide path on the dentinal crack formation of ProTaper Next system.

OBJECTIVES: The aim was to evaluate dentinal crack formation after root canal preparation with ProTaper Next system (PTN) with and without a glide path. MATERIALS AND METHODS: Forty-five mesial roots of mandibular first molars were selected. Fifteen teeth were left unprepared and served as controls. The experimental groups consist of mesiobuccal and mesiolingual root canals of remaining 30 teeth, which were divided into 2 groups (n = 15): Group PG/PTN, glide path was created with ProGlider (PG) and then canals were shaped with PTN system; Group PTN, glide path was not prepared and canals were shaped with PTN system only. All roots were sectioned perpendicular to the long axis at 1, 2, 3, 4, 6, and 8 mm from the apex, and the sections were observed under a stereomicroscope. The presence/absence of cracks was recorded. Data were analyzed with chi-square tests with Yates correction. RESULTS: There were no significant differences in crack formation between the PTN with and without glide path preparation. The incidence of cracks observed in PG/PTN and PTN groups was 17.8% and 28.9%, respectively. CONCLUSIONS: The creation of a glide path with ProGlider before ProTaper Next rotary system did not influence dentinal crack formation in root canals.

Is Pulp Inflammation a Prerequisite for Pulp Healing and Regeneration?

The importance of inflammation has been underestimated in pulpal healing, and in the past, it has been considered only as an undesirable effect. Associated with moderate inflammation, necrosis includes pyroptosis, apoptosis, and nemosis. There are now evidences that inflammation is a prerequisite for pulp healing, with series of events ahead of regeneration. Immunocompetent cells are recruited in the apical part. They slide along the root and migrate toward the crown. Due to the high alkalinity of the capping agent, pulp cells display mild inflammation, proliferate, and increase in number and size and initiate mineralization. Pulp fibroblasts become odontoblast-like cells producing type I collagen, alkaline phosphatase, and SPARC/osteonectin. Molecules of the SIBLING family, matrix metalloproteinases, and vascular and nerve mediators are also implicated in the formation of a reparative dentinal bridge, osteo/orthodentin closing the pulp exposure. Beneath a calciotraumatic line, a thin layer identified as reactionary dentin underlines the periphery of the pulp chamber. Inflammatory and/or noninflammatory processes contribute to produce a reparative dentinal bridge closing the pulp exposure, with minute canaliculi and large tunnel defects. Depending on the form and severity of the inflammatory and noninflammatory processes, and according to the capping agent, pulp reactions are induced specifically.

Apical root canal transportation of different pathfinding systems and their effects on shaping ability of ProTaper Next.

BACKGROUND: This study aimed to compare glide path preparation of different pathfinding systems and their effects on the apical transportation of ProTaper Next (Dentsply Maillefer, Ballaigues, Switzerland) in mesial root canals of extracted human mandibular molars, using digital subtraction radiography. MATERIAL AND METHODS: The mesial canals of 40 mandibular first molars (with curvature angles between 25° and 35°) were selected for this study. The specimens were divided randomly into 4 groups with 10 canals each. Glide paths were created in group 1 with #10, #15 and #20 K-type (Dentsply Maillefer, Ballaigues, Switzerland) stainless steel manual files; in group 2 with Path-File (Dentsply Maillefer) #1, #2, and #3 and in group 3 with #16 ProGlider (Dentsply Maillefer) rotary instruments; in group 4 no glide paths were created. All canals were instrumented up to ProTaper Next X2 to the working length. A double digital radiograph technique was used, pre and post-instrumentation, to assess whether apical transportation and/or aberration in root canal morphology occurred. Instrument failures were also recorded. The data were analyzed statistically using ANOVA and Tukey tests (p<0.05). RESULTS: No significant differences were found among groups regarding apical transportation (p>0.05). Two ProTaper Next instruments failed in-group 4. CONCLUSIONS: Within the parameters of this study, there was no difference between the performance of path-finding files and ProTaper Next system maintained root canal curvature well and was safe to use either with path-finding files or alone. Key words:Glide path, PathFile, ProGlider, ProTaper Next, transportation.