Influence of acidic pH on antimicrobial activity of different calcium silicate based–endodontic sealers

Objective

To investigate the antibacterial activity of calcium silicate–based sealers (CSBSs) against Enterococcus faecalis biofilm in a neutral or acidic condition.

Materials and methods

Dentin cylinders (4 mm length) were prepared and infected with 3-week-old E. faecalis. The samples were filled with BioRoot RCS (BR), EndoSequence BC (ES), and NeoMTA Plus (NMTA) and incubated in either neutral or acidic conditions for 7 days (n=10/group). Sterile or infected samples alone were used as the positive and negative control. The root canal sealers were removed after 7 days, and the remaining bacteria on dentinal walls were determined by colony-forming units (CFUs/ml), and three samples from each group were visualized under a confocal laser scanning microscope (CLSM). The pH was also measured (n=3/group) after 4 h and 7 days of incubation at 37°C in both conditions.

Results

In the neutral condition, all sealers significantly decreased the log-CFU values (p<0.05), while in the acidic condition, the log-CFU reduction was less for ES and NMTA, but a higher reduction was observed in BR (p<0.05). The antibacterial activity of CSBSs was similar in neutral conditions (p>0.05), and BR showed a greater antibacterial effect than ES and NMTA in the acidic condition (p<0.05). The pH of BR, ES, and NMTA ranged from 8.2 to 8.8 in the neutral condition in the presence of dentin after 7 days. However, acidic conditions reduced the pH values to 7.8 for BR, 6.0 for ES, and 5.8 for NMTA.

Conclusions

All CSBSs showed similar antibacterial activity in neutral conditions, while acidic pH had a reducing antibacterial effect on CSBSs.

Clinical relevance

Inflammatory pH decreased the antibacterial properties of CSBSs depending on the sealer type.

     

Impacts of different Nickel–Titanium rotary and reciprocating root canal preparation systems on the amount of apically extruded debris

This study aimed to evaluate the amount of apically extruded debris caused by different NiTi files. One hundred mandibular premolars were included in this study. The specimens were divided into five groups (n = 20): (i) TruNatomy, (ii) WaveOne Gold, (iii) 2Shape, (iv) ProTaper Next and (v) Reciproc Blue. The extruded debris was collected into preweighed Eppendorf tubes. These tubes were weighed again, and the net weight of debris was calculated. Data were statistically analysed, and the significance level was set at 5%. The least amount of extruded debris was observed in the TruNatomy group (p < 0.05). Statistically significant differences were not found among (iii), (iv) and (v) groups (p > 0.05). However, these groups resulted in significantly higher amounts of debris when compared to (i) and (ii) groups (p < 0.05). The results lead us to conclude that all instrumentation systems caused apical extrusion of debris at varying weights.     

Impact of nickel–titanium instrumentation of the root canal on clinical outcomes: a focused review

Nickel-titanium (NiTi) root canal instruments have improved the technical quality of enlarging and shaping. These instruments have been shown to prepare even severely curved root canal with fewer procedural errors than traditional stainless steel hand instruments. While it would appear that these instruments might enhance clinical outcomes, very few studies have assessed their impact when used in primary root canal treatment. Clinical studies investigating the outcome of primary root canal treatment using nickel-titanium hand or rotary instruments were identified (MEDLINE database) using appropriate key words in an attempt to determine if there have been enhanced outcomes with these instruments. Evidence from one clinical trial suggests that (i) better maintenance of the original canal curvature and shape results in increased success rates and (ii) that ledging of root canals results in reduced success rates. Evidence from two studies indicates that the use of NiTi-either hand or rotary-instruments significantly increases success rates of primary nonsurgical root canal treatment compared with the use of stainless steel hand instruments, while three investigations failed to show any significant differences.     

Cytotoxicity and the Effect of Temperature on Physical Properties and Chemical Composition of a New Calcium Silicate–based Root Canal Sealer

IntroductionThe suitability of EndoSequence BC Sealer (BC Sealer; Brasseler USA, Savannah, GA) for warm vertical compaction has been questioned. The aim was to evaluate the cytotoxicity and the effect of heating on the physicochemical properties of a new calcium-based root canal sealer (EndoSequence BC Sealer HiFlow [HiFlow]) in comparison with EndoSequence BC Sealer.MethodsHuman periodontal ligament fibroblasts were incubated for 1, 2, or 3 days with material extracts of different concentrations, and cell viability was evaluated by Cell Counting Kit-8 (Enzo Life Sciences Inc, Burlington, Ontario, Canada). The setting time, flow, film thickness, microhardness, radiopacity, and radiopacity of the 2 sealers were measured according to ISO 6786/2012. The continuous changes in viscosity were tested by a stress-controlled rheometer at shear rates ranging from 0.01–10 s⁻¹ and different temperatures, and chemical composition was assessed by Fourier-transform infrared spectroscopy.ResultsCell viability was significantly decreased on day 3 for the 1:4 diluted extract from both materials. The setting time, microhardness, and solubility of HiFlow were similar to BC Sealer at 37°C and 100°C. HiFlow had significantly higher flow and radiopacity than BC Sealer at room temperature (P < .05), and when heated, HiFlow retained its higher flow and lower film thickness (P < .05). Both sealers showed decreasing viscosity with increasing shear rate, and at a shear rate of 0.01 and 0.1 s⁻¹, HiFlow exhibited lower viscosity than BC Sealer at all temperatures measured. The chemical composition of the 2 sealers was not changed by heating.ConclusionsHiFlow showed better performance on flow/viscosity and film thickness, especially under high temperatures, which are generated by the commonly used warm vertical compaction technique.     

Ion release and physical properties of CPP–ACP modified GIC in acid solutions

A new glass-ionomer cement (GIC) (Fuji VII? EP) includes 3% (w/w) casein phosphopeptide–amorphous calcium phosphate (CPP–ACP) to enhance ion release.ObjectivesTo assess this new GIC compared with a GIC without CPP–ACP (Fuji VII?) with respect to ion release, changes in surface hardness and in mass under a variety of acidic and neutral conditions.MethodsEighty blocks of Fuji VII? (F7) and Fuji VII? EP (F7EP) were subjected to three acidic solutions (lactic and citric acids pH 5.0, hydrochloric acid pH 2.0) and water (pH 6.9) over a three-day period. Ion release, surface hardness and weight measurements were carried out every 24 h.ResultsHigher calcium ion release from F7EP was observed under all acidic conditions. Increased inorganic phosphate ion release was observed for F7EP in hydrochloric and citric acids. Fluoride ion release was similar between F7 and F7EP under all conditions but was significantly higher in acids compared with water. After three days there was no significant difference in surface hardness (p > 0.05) between the two materials under all conditions except hydrochloric acid. Minimal change in mass was observed for F7 and F7EP in water, lactic and hydrochloric acids, however citric acid caused significantly more mass loss compared with water (p < 0.001).ConclusionIncorporation of 3% (w/w) CPP–ACP into F7 enhanced calcium and phosphate ion release, with no significant change in fluoride ion release and no adverse effects on surface hardness or change in mass.Clinical significance statementGICs have the potential to release fluoride ions particularly under acidic conditions associated with dental caries and erosion. A new GIC containing CPP–ACP and fluoride releases not only fluoride ions but also calcium and phosphate ions under acidic conditions which should help to inhibit demineralisation associated with caries and erosion.     

Altered physical–chemical properties of home bleaching gels after an accelerated stability study and their effects on tooth enamel

Clinical Oral Investigations - To investigate the physical–chemical properties of home bleaching gels based on Carbamide Peroxide (CP) and Hydrogen Peroxide (HP) after accelerated stability...     

Do chlorhexidine and ethanol improve bond strength and durability of adhesion of fiber posts inside the root canal?

Objectives

The aim was to investigate the effects of chlorhexidine and ethanol pretreatment of the root canal on push-out bond strengths and durability of adhesion of fiber posts luted with two different adhesive strategies.

Materials and methods

One hundred twenty human anterior teeth were endodontically treated. After post space preparation, the root canals were irrigated using 1 % sodium hypochlorite (NaOCl) applied with passive ultrasonic irrigation followed by distilled water (control). In pretreatment (PT) group, chlorhexidine (CHX) root canals were irrigated using 2 % chlorhexidine; and in the PT group, 99 % ethanol was used prior application of the luting agent. Two different post-and-luting systems with an etch-and-rinse (CX) adhesive approach (n?=?60) and a self-adhesive resin cement (RX; n?=?60) were inserted into the root canals. Bond strengths were evaluated initially and after thermocycling and storage for 6 months using push-out tests.

Results

Bond strength was significantly affected by the adhesive strategy (p?<?0.0005), the pretreatment (p?<?0.0005) and the location inside the root canal (p?<?0.0005; repeated measurement ANOVA). Ethanol significantly increased bond strengths irrespective of the luting agent used compared to the control and CHX group (p?<?0.05; Tukey's B).

Conclusion

Ethanol significantly increased bond strength of the CX and the RX system inside the root canal and could be recommended as a final rinse for luting fiber posts using an ethanol-based etch-and-rinse adhesive system or self-adhesive resin cement.

Clinical relevance

PT of the root canal using ethanol seems to facilitate adhesive luting of fiber posts with the tested adhesive system and luting cements.     

Root fillings with a matched-taper single cone and two calcium silicate–based sealers: an analysis of voids using micro-computed tomography

Clinical Oral Investigations - To compare the percentage of voids in matched-taper single-cone fillings with GuttaFlow Bioseal or BioRoot RCS root canal sealers, using micro-computed tomography....     

Root and root canal variations of the human maxillary and mandibular third molars in a Chinese population: A micro–computed tomographic study

ObjectivesTo investigate the anatomical variations of the root and root canal configuration of the human third molars.DesignsA total of 130 maxillary and 130 mandibular third molars were collected from a native Chinese population. All teeth were scanned by micro–computed tomography. After 3D reconstruction, the root and canal morphology of each tooth was examined both qualitatively and quantitatively.ResultsFor maxillary molars, a single fused root (67 cases, 51.5%) and a single root canal system (64 cases, 49.2%) was most common root/canal form; the typical three-rooted molars were detected only in 33 cases (25.4%), and the secondary MB canals were detected only in 9 molars (6.9%). For mandibular molars, 62 teeth were single-rooted (47.7%) and 42 had a single root canal system (32.3%); 20 singled-rooted and 60 double-rooted molars exhibited independent mesial and distal root canal systems (61.5%), and the type 1-1 canal was the most common configuration for mesial (57 cases) and distal (81 cases) root canal systems. C-shaped canals were detected in 11 maxillary and 36 mandibular single-rooted molars. The mean root surface area, root and crown volume of mandibular third molars were significantly higher than the maxillary third molars (P < 0.01).ConclusionThe root canal system of the third molars may exhibit several anatomic variations. Whereas in most of cases, the degree of the canal differentiation was at a low level, and the canal form was not complicate.     

Radiographic features and outcome of root canal treatment carried out in the Łódź region of Poland

AIM: The aim of this study was to assess the radiographic features and factors affecting the long-term results of root canal treatment in the Lód? region of Poland. METHODOLOGY: Three hundred and fifty-five periapical radiographs of previously endodontically treated teeth (282 root-filled teeth and 73 teeth with pulpotomy) from 236 patients were evaluated in the study. The patients were aged from 15 to 76 years and randomly selected amongst subjects referred to the Institute of Dentistry. Medical University of Lód? and two private dental practices. The radiographs were examined by the authors according to criteria proposed by De Cleen et al. (1993) using an illuminated viewbox in a dark room. The Fisher's exact test was used to compare the frequencies in teeth groups. RESULTS: Amongst root-filled teeth, 49% were adequately filled within 0-2 mm of the radiographic apex. Periapical radiolucencies were observed in 25% of root-filled teeth. Teeth without periapical pathosis were more often filled within 0-2 mm of the apex (59%) than teeth with pathosis (17%). Teeth were most often adequately filled (64%) in patients attending the Institute of Dentistry. In patients attending the dental outpatients' departments, 71% of teeth were inadequately filled. Amongst the teeth treated with pulpotomy, 67% had a periapical radiolucency. CONCLUSION: The radiographic technical quality of the root canal treatment was associated with the outcome that root fillings of adequate standard were associated with health more often than inadequate root fillings. Pulpotomy was associated with periapical disease in the majority of cases.     

Characterization of two Ni–Cr dental alloys and the influence of casting mode on mechanical properties

PurposeThe aim of this study was to evaluate the tensile strength, elongation, microhardness (MHV), composition and microstructure of two Ni–Cr based alloy, cast under different casting conditions.MethodsBefore casting, the alloy ingots were evaluated as regards composition (EDX) and microstructure (Optical microscopy, SEM and EDX). The casting conditions were as follows: electromagnetic induction in an environment controlled with argon (EWA), electromagnetic induction in an environment under vacuum (EWV), electromagnetic induction without atmosphere control (EWNC) and blowtorch (BT). For each condition, 16 specimens were obtained, each measuring 25 mm high and 2.5 mm in diameter. The ultimate tensile strength (UTS) and elongation (EL) tests were performed in a Kratos machine (1.0 mm/min). Fractured specimens were embedded in bakelite resin and polished for Vickers Microhardness analysis (1000 g/10 s) with 4 penetrations in each specimen. The UTS, EL and MHV results were evaluated for two-way ANOVA and Tukey's test (α = 0.05).ResultsThe cross-product interaction was statistically significant for all properties evaluated (p < 0.0001), lower UTS, VHN and higth elongation means were observed for the Ni–Cr–Mo–Be alloy tested when cast under the induction/argon (p < 0.05). Higher UTS means were found for Ni–Cr–Mo–Ti alloy tested when cast under the induction/vacuum, and induction/air and flame/air condition (p < 0.05). The two alloys show a microstructure with a dendritic formation with the presence of eutectic presence.ConclusionThe Ni–Cr–Mo–Ti alloy showed higth UTS, MHV and lowest EL comparaded with the tradicional Ni–Cr–Mo–Be, that show lowest UTS, MHV and higter EL when cast on induction/argon.     

Effects of toothbrush abrasion on surface and antibacterial properties of hydroxyapatite–tryptophan complex with gray titania

Odontology - Photocatalysts have attracted attention in the medical field for their antibacterial effects. However, typical photocatalysts are activated by ultraviolet rays, which may have adverse...     

Comparative chemical properties,bioactivity, and cytotoxicity of resin-modified calcium silicate–based pulp capping materials on human dental pulp stem cells

Clinical Oral Investigations - This study investigated the cytotoxicity, the residual monomer release, degree of conversion (DC), calcium ion (Ca2+) release, and crystal structure of TheraCal PT...