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The main biological goal in clinical dentistry remains to prevent micro-organisms from exerting pathogenic effects by establishing non-commensal biofilms or entering the wrong niches [...]

In 2011, the first consensus conference on guidelines for the use of cone-beam computed tomography (CBCT) was convened by the Swiss Society of Dentomaxillofacial Radiology (SGDMFR). This conference covered topics of oral and maxillofacial surgery, temporomandibular joint dysfunctions and disorders, and orthodontics. In 2014, a second consensus conference was convened on guidelines for the use of CBCT in endodontics, periodontology, reconstructive dentistry and pediatric dentistry. The guidelines are intended for all dentists in order to facilitate the decision as to when the use of CBCT is justified. As a rule, the use of CBCT is considered restrictive, since radiation protection reasons do not allow its routine use. CBCT should therefore be reserved for complex cases where its application can be expected to provide further information that is relevant to the choice of therapy. In periodontology, sufficient information is usually available from clinical examination and periapical radiographs; in endodontics alternative methods can often be used instead of CBCT; and for implant patients undergoing reconstructive dentistry, CT is of interest for the workflow from implant planning to the superstructure. For pediatric dentistry no application of CBCT is seen for caries diagnosis.

Transforming growth factor beta 1 (TGF-β1) is a key morphogen in regenerative endodontics; yet, its location within the hard tissue phase of dentin and its availability in mature roots have not been fully elucidated.Young mature (n = 8) and immature (n = 11) roots from sound premolars were obtained from 13 orthodontic patients aged 17 ± 1 and 12 ± 1 years, respectively. Roots were cleaned of organic remnants in 5% sodium hypochlorite. The width of the minor foramen was measured using a digital microscope. TGF-β1 distribution was assessed in 3 roots per group by immunostaining combined with confocal laser scanning microscopy. The root dentin of the remaining 13 roots was powdered and decalcified in 17% EDTA to determine the overall levels of hard tissue-embedded TGF-β1 by enzyme-linked immunosorbent assay. Data were compared between groups using the Student t test (α = .05).The minor foramen was 168 ± 49 μm versus 557 ± 295 μm in mature compared with immature roots (P.05). TGF-β1 was highly stainable toward the pulp space in both groups. It was clearly associated with peritubular dentin and apparently absent in nontubular outer dentin. TGF-β1 content was 115 ± 31 pg and 74 ± 35 pg/100 mg mature versus immature root dentin, respectively (P.05).TGF-β1 is deposited into the peritubular dentin. It should be possible to release this molecule in regenerative endodontic procedures from young mature roots as well as immature roots.

The conditioning of the root canal wall during chemo-mechanical root canal treatment differentially affects the adhesion of root canal sealers. This investigation evaluated the impact of sodium hypochlorite (NaOCl) concentration as used in a root canal irrigation concept called continuous chelation, with 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) contained in the NaOCl solution that is applied. Fourier-transform infrared spectra of the dentinal wall were gathered. The consequential effects on push-out bond strength of an epoxy resin (AH Plus) versus a hydraulic CaSi sealer (BioRoot RCS) were assessed. Single-rooted extracted human teeth were used and irrigated with pure NaOCl at a concentration of 0% (physiological saline), 2.5%, or 5.25%. Dual Rinse HEDP (9%) was added to the solutions, or not added for further control. Pure NaOCl solutions caused a decrease in the amide III: phosphate ratios, which was counter-acted by the addition of HEDP. It was observed that the adhesion of the epoxy resin sealer under investigation was negatively affected by this NaOCl deproteinization of the canal wall in a dose-dependent manner, while the opposite was observed with the CaSi sealer. HEDP when used in conjunction with NaOCl was beneficial for the adhesion of both sealers.

The authors of this narrative review aimed to address various experimental methods and make recommendations for how research should move forward in the context of studying biomarkers in clinical Endodontic research. The approach adopted is exemplified using two prominent clinical problems, namely (a) the 'reversible' versus 'irreversible' pulpitis conundrum and (b) persistent idiopathic dentoalveolar pain (PIDAP). Pulpitis under deep caries or dentinal cracks is understood from a histological perspective, but clinical assessment tools to indicate irreversibly inflamed aspects of the dental pulp are elusive. PIDAP, on the other hand, is a diagnosis of exclusion; its pathophysiology is complex and not understood sufficiently to avoid unnecessary dental treatments. This review addresses how diagnostic biomarkers could further our understanding of those and other clinical problems, and how issues can be tackled from a methodological point of view. Hence, different methodological approaches to identify suitable diagnostic biomarker(s) or use known biomarkers are presented. The importance of asking a relevant research question, collecting the most suitable fluid and using the ideal collection vehicle for the research question under investigation is discussed based on the defined clinical problems.

The addition of Dual Rinse HEDP, an etidronate powder, to a sodium hypochlorite (NaOCl) solution can create a combined single endodontic irrigant with a soft tissue-dissolving and a decalcifying effect, which can replace traditional alternating irrigation with chemically non-compatible solutions. While the short-term compatibility between NaOCl and 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) has been shown, it remains unclear whether ultrasonic activation of a combined NaOCl &amp, HEDP solution immediately reduces the available chlorine and/or renders the NaOCl ineffective in dissolving organic tissue remnants. This was tested in three experiments: (1) direct activation in test tubes in an ultrasonic bath and then the activation by an ultrasonically oscillating tip (IrriSafe) in (2) an epoxy resin model containing a simulated isthmus filled with gelatin, and (3) extracted teeth with simulated resorption cavities filled with soft tissue. The control solutions were physiological saline and 2.5% NaOCl without HEDP. In (1), available chlorine after 30 s of ultrasonic activation (37 kHz) of test and control solution was assessed, as well as shrimp tissue weight loss in direct exposure. In (2) and (3), the ultrasonic tip was driven at 1/3 of full power using the respective unit, and areas of removed gelatin from the isthmus and tissue weight loss were used as the outcomes, respectively. Experiment (1) revealed no negative impact by HEDP on available chlorine (1), while all three experiments showed a highly significant (p &gt, 0.001) synergistic effect, which was not hampered by HEDP, between NaOCl and ultrasonic activation regarding tissue weight loss (1, 3) and dissolution of gelatin (2).

Introduction Hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl) solutions are similar in that they contain oxidizing agents with a bleaching effect. NaOCl solutions are stable at high pH, at which they also exert increased cleansing/proteolysis. H2O2 solutions, on the other hand, are natively acidic, yet gain bleaching power on organic stains when alkalized. It was investigated whether alkalizing a H2O2 solution would also let it dissolve soft tissue or increase its bleaching power on blood-stained dentin. Methods The stability of alkalized H2O2 solutions was assessed by iodometric titration. Soft tissue dissolution was investigated on porcine palatal mucosa. The bleaching effect (ΔL*) after 60 min of exposure was monitored in blood-stained human dentin using a calibrated spectrophotometer. To compare similar molarities, 2.5% H2O2 solutions were used here, and 5.0% NaOCl was used as the positive control, while non-buffered saline solution served as the negative control. Results Adding alkali (NaOH) to the H2O2 solutions rendered them unstable in a dose-dependent manner. A H2O2 solution of pH 11.2 was chosen for the main experiments (tissue dissolution and bleaching effect) and compared to a native counterpart (pH 4.7). Alkalizing the H2O2 solution had no discernible effect on its soft tissue dissolution or bleaching power (P = .75 compared to the native H2O2 solution). The NaOCl solution of similar strength had a considerably (P < .001) higher tissue dissolving and bleaching effect under current conditions. Conclusions The proteolytic/bleaching effects of NaOCl solutions are unique, and cannot be achieved by altering the pH of peroxide solutions., Journal of endodontics, 47 (2), ISSN:0099-2399, ISSN:1878-3554

Introduction A clinically useful all-in-one endodontic irrigant with combined proteolytic and decalcifying properties is still elusive. In this study, the chemical effects of dissolving the tetrasodium salts of 1-hydroxyethane 1,1-diphosphonic acid (Na 4 HEDP) or Na 4 EDTA directly in sodium hypochlorite (NaOCl) irrigants in polypropylene syringes were assessed during the course of 1 hour. Methods The solubility of the salts in water was determined. Their compatibility with 1% and 5% NaOCl was measured by iodometric titration and in a calcium complexation experiment by using a Ca 2+ -selective electrode. Results The salts dissolved within 1 minute. The dissolution maximum of Na 4 HEDP in water (wt/total wt) was 44.6% ± 1.6%. The corresponding dissolution maximum of Na 4 EDTA was 38.2% ± 0.8%. Na 4 HEDP at 18% in 5% NaOCl caused a mere loss of 16% of the initially available chlorine during 1 hour. In contrast, a corresponding mixture between NaOCl and the Na 4 EDTA salt caused 95% reduction in available chlorine after 1 minute. Mixtures of 3% Na 4 EDTA with 1% NaOCl were more stable, but only for 30 minutes. Na 4 HEDP lost 24% of its calcium complexation capacity after 60 minutes. The corresponding loss for Na 4 EDTA was 34%. Conclusions The compatibility and solubility of particulate Na 4 HEDP with/in NaOCl solutions are such that these components can be mixed and used for up to 1 hour. In contrast, short-term compatibility of the Na 4 EDTA salt with NaOCl solutions was considerably lower, decreasing at higher concentrations of either compound. Especially for Na 4 HEDP but also for Na 4 EDTA, the NaOCl had little effect on calcium complexation.

Objectives This study aimed to investigate bleaching effects of common endodontic irrigants on human whole blood and blood-stained dentin. Specifically, it was assessed whether sodium hypochlorite at a clinically recommended concentration (2.5% NaOCl) would bleach with similar efficacy as a peroxide-based irrigant at higher molarity (5% H2O2). Furthermore, the effects of a NaOCl-compatible chelator with a high affinity to iron (Dual Rinse HEDP) were investigated. Methods Human whole blood was mixed at a 1:20 ratio with either phosphate-buffered saline, 9% HEDP, 2.5% NaOCl, 2.5% NaOCl containing 9% HEDP, or 5% H2O2. Effects were assessed spectrometrically and photographically. Human dentin specimens were prepared with a methacrylate reservoir for liquids and a polished assessment side over 1 mm dentin thickness. Dentin was stained using human whole blood for 3 weeks and subsequently exposed to the irrigants for 60 min. Measurements were performed in the CIELAB color space. Results were compared using parametric tests with the alpha-type error set to 5%. Results When directly exposed, the solutions containing NaOCl completely discolored the blood, while the 5% H2O2 exerted a bleaching effect without complete dissolution of dissolved matter, and the pure 9% HEDP had no effect at all. The NaOCl solutions bleached blood-stained dentin more efficiently than H2O2 (p < 0.05). Conclusions Under the current conditions, the 2.5% NaOCl solution had a stronger bleaching effect on blood and blood-stained dentin than 5% H2O2. HEDP did not have any direct impact on blood color or NaOCl-derived bleaching., Heliyon, 5 (5)

The application of biomaterials used in regenerative endodontics should be traceable. In this study, we checked some basic effects of rendering a fibrin hydrogel radiopaque using an iodine-based contrast agent (iodixanol) approved for systemic application. Fibrin hydrogels were prepared from a fibrin sealant (Tisseel) using either an isotonic iodixanol solution (Visipaque 320, test) or Tris buffer (control) as a diluent. Gelation kinetics, radiopacity, and swelling of lyophilized hydrogels were tested using standard methods. Hydrogel structure was evaluated using scanning electron microscopy (SEM). Furthermore, iodixanol release from the test gels was assessed using spectrophotometry, and tissue compatibility was compared between test and control hydrogels using the chick chorioallantoic membrane (CAM) assay. Results were compared using pairwise t-test, p < 0.05. Iodixanol caused a 70-fold delay in gelation to 26 min in the test compared to the control hydrogels (22 ± 1 s). Radiopacity of the test gels was 1.9 ± 0.2 mm Al/mm, compared to zero in the control hydrogels. Lyophilized hydrogel swelling was strongly reduced when iodixanol was added to the hydrogel (p < 0.05). Test hydrogels had an altered SEM appearance compared to controls, and exhibited a reduced porosity. Iodixanol release from the test hydrogels reached 14.5 ± 0.5% after 120 h and then ceased. This release did not have any apparent toxic effect and neither affected the viability, nor the physiology or vascularization of the CAM of fertilized chicken eggs. Iodixanol can render a fibrin hydrogel radiopaque and maintains its tissue compatibility, yet impacts gelation kinetics and hydrogel porosity.

Many clinicians use household bleach to irrigate root canals. Sodium hypochlorite solutions are also available from dental suppliers. We compared physicochemical features of these products and investigated their impact on pulp tissue dissolution.Six different brands of household bleach were bought from drugstores. These were compared with Chlor-XTRA and technical NaOCl solutions of controlled concentration and alkalinity regarding their chlorine content (wt% NaOCl), pH, alkaline capacity, osmolarity, surface tension (Wilhelmy plate method), and price. Bovine pulp tissue (n = 10 specimens per group) dissolution at 37°C by test and control solutions adjusted to 1.0% NaOCl was assessed. Reduction in tissue weight was compared between groups by one-way analysis of variance, followed by Bonferroni correction (P.05).The pH of undiluted solutions ranged between 11.1 and 12.7. Batches of the same product differed in NaOCl content. No product contained more than an equivalent of 0.1 mol/L NaOH. One household bleach brand (Safeway Bleach Summit Fresh) was slightly alkalized; the other solutions under investigation were not. Osmolarity was similar between products. The surface tension of Chlor-XTRA and Safeway Bleach Summit Fresh was about half that of the other solutions. Tissue dissolution was statistically similar (P.05) among all solutions. Price was about 100-fold higher per liter of Chlor-XTRA compared with household bleach.Other than its price, the Chlor-XTRA solution had no unique features. In contrast to an earlier report, reduced surface tension did not result in greater soft tissue dissolution by NaOCl.

When sodium hypochlorite solutions react with tissue, their pH drops and tissue sorption decreases. We studied whether stabilizing a NaOCl solution at a high pH would increase its soft-tissue dissolution capacity and effects on the dentin matrix compared with a standard NaOCl solution of the same concentration and similar initial pH.NaOCl solutions were prepared by mixing (1:1) a 10% stock solution with water (standard) or 2 mol/L NaOH (stabilized). Physiological saline and 1 mol/L NaOH served as the controls. Chlorine content and alkaline capacity of NaOCl solutions were determined. Standardized porcine palatal soft-tissue specimens and human root dentin bars were exposed to test and control solutions. Weight loss percentage was assessed in the soft-tissue dissolution assay. Three-point bending tests were performed on the root dentin bars to determine the modulus of elasticity and flexural strength. Values between groups were compared using one-way analysis of variance with the Bonferroni correction for multiple testing (α.05).Both solutions contained 5% NaOCl. One milliliter of the standard and the stabilized solution consumed 4.0 mL and 13.7 mL of a 0.1-mol/L HCl solution before they reached a pH level of 7.5, respectively. The stabilized NaOCl dissolved significantly more soft tissue than the standard solution, and the pH remained high. It also caused a higher loss in elastic modulus and flexure strength (P.05) than the control solutions, whereas the standard solution did not.NaOH-stabilized NaOCl solutions have a higher alkaline capacity and are thus more proteolytic than standard counterparts.

Pulpal diagnostics might be improved by using molecular markers found in dentinal fluid. In the current pilot study, we tested whether matrix metallopeptidase 9 (MMP-9) levels in dentinal fluid were detectable and differed between pulps from symptomatic teeth diagnosed with irreversible pulpitis and healthy counterparts.Thirty-one patients participated; 19 were diagnosed with irreversible pulpitis, and 12 were in need of replacement of a filling close to the pulp space in a clinically healthy tooth. Dentinal fluid was collected during a period of 2 minutes from dentin cavities by using folded polyvinylidene difluoride (PVDF) membranes, which were then transferred to microcentrifugation tubes containing physiologic saline solution. Total MMP-9 levels in these solutions were assessed by using a human MMP-9 fluorescent assay, detection limit 0.25 ng/mL. MMP-9 levels between groups were compared by using Mann-Whitney U test (alpha0.05).Three specimens from the symptomatic teeth were not included because coronal pulps proved to be necrotic on access. Dentinal fluid samples from symptomatic teeth had significantly higher MMP-9 levels than those from clinically healthy counterparts (P.05). However, merely 7 of the 16 pulpitis samples contained detectable levels of MMP-9. None of the clinically healthy control specimens contained any detectable amounts of MMP-9.With a sensitive assay, it was possible to detect an enzyme linked with pulp tissue destruction (MMP-9) in dentinal fluid. However, the collection method needs to be improved to provide predictable fluid yields. Longitudinal studies should be performed to assess the predictive value of molecular markers in dentinal fluid on pulpal pathosis.

AIM To assess two contemporary rotary instrumenting systems subjectively and objectively in a pre-clinical student course setting. METHODOLOGY Undergraduate dental students (n = 44) prepared mesiolingual canals of 3D-printed mandibular molar replicas (RepliDens, Zurich, Switzerland). The HyFlex and BioRace rotary systems, both previously unknown to the students, were used according to the manufacturers' guidelines after a short theoretical introduction. For comparison, a first-generation rotary system (ProFile .04), which the students knew from their previous education, was then used in a third RepliDens. Questionnaires were issued to note subjective experiences immediately after instrumentation. Objectively, time to instrument to size 40, .04 taper and shaping outcomes were analysed. Categorical data were compared using chi-square and Fisher's exact tests, numerical data according to goodness of fit to the normal distribution, P < 0.05. RESULTS Subjectively, the students liked the file size and sequence designation in the BioRace system significantly (P < 0.05) better than in the HyFlex counterpart, whilst they found better controllability with the HyFlex (P < 0.05), and reported no difference in cutting efficiency. They preferred both systems to the ProFile. Objectively, canal transportation was significantly less with the HyFlex (and the ProFile) systems compared to BioRace (P < 0.05). Both systems under investigation were statistically similar in terms of file fractures (nil), length control, and instrumentation time, which was considerably faster than with the ProFile control system. CONCLUSIONS HyFlex and BioRace had perceived and quantifiable strengths and weaknesses. Both systems were equally liked by the students and preferred over the ProFile first-generation rotary system.

Objective. The goal of this study was to compare the dissolving potential of Dakin’s solution with that of equivalent buffered and unbuffered sodium hypochlorite solutions on fresh and decayed tissues. In addition, the antimicrobial effect of Dakin’s solution and equivalent unbuffered hypochlorite was tested. Study design. Tissue specimens were obtained from freshly dissected pig palates. Unbuffered 2.5% and 0.5% sodium hypochlorite solutions and 0.5% solutions buffered at a pH of 12 and a pH of 9 (Dakin’s solution) were tested on fresh and decayed tissue. Tissue decay was assessed histologically. Antimicrobial testing was performed with Enterococcus faecalis in dentin blocks and on filter papers. Results. The 2.5% NaOCl solution was substantially more effective than the three 0.5% solutions in dissolving the test tissues. Buffering had little effect on tissue dissolution, and Dakin’s solution was equally effective on decayed and fresh tissues. No differences were recorded for the antibacterial properties of Dakin’s solution and an equivalent unbuffered hypochlorite solution. Conclusions. In contrast to earlier statements, the results of this study do not demonstrate any benefit from buffering sodium hypochlorite with sodium bicarbonate according to Dakin’s method. An irrigation solution with less dissolving potential may be obtained by simply diluting stock solutions of NaOCl with water. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2002;94:756-62)

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 degrees 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 degrees C. Killing efficacy of diluted NaOCl solutions against 48-h incubations of Enterococcus feacalis ATCC 29212 was compared at 45 degrees C and 20 degrees C. Using the heating device, a 20 degrees C solution reached 45 degrees C and 60 degrees C in 7 and 20 min, respectively. Solutions remained stable during the observation period. The 1% NaOCl solution at 45 degrees C dissolved pulp tissues as effectively as the 5.25% solution at 20 degrees C, while the 60 degrees 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 degrees C and 45 degrees C.