4-META/MMA-TBB resin containing nano hydroxyapatite induces the healing of periodontal tissue repair in perforations at the pulp chamber floor.

We aimed to evaluate the materials based on 4-methacryloxyethyl trimellitate anhydride/methyl methacrylate tri-n-butylborane (Super-bond [SB]) and nano hydroxyapatite (naHAp) for the repair of perforation at pulp chamber floor (PPF) in vitro and in vivo models. SB and naHAp were mixed in the mass ratio of 10% or 30% to produce naHAp/SB. Human periodontal ligament stem cells (HPDLSCs) were cultured on resin discs of SB or naHAp/SB to analyze the effects of naHAp/SB on cell adhesion, proliferation, and cementoblastic differentiation. A rat PPF model was treated with SB or naHAp/SB to examine the effects of naHAp/SB on the healing of defected cementum and periodontal ligament (PDL) at the site of PPF. HPDLSCs were spindle-shaped and adhered to all resin discs. Changing the resin from SB to naHAp/SB did not significantly alter cell proliferation. Both 10% and 30% naHAp/SB were more effective than SB in promoting cementoblastic differentiation of HPDLSCs. In the rat PPF model, 30% naHAp/SB was more effective than SB in promoting the formation Sharpey's fiber-like structures with expression of the PDL-related marker and cementum-like structures with expression of cementum-related markers. In conclusion, 30% naHAp/SB can be the new restorative material for PPF because it exhibited the abilities of adhering to dentin and healing of defected periodontal tissue.

Ultrasonic agitation reduces the time of calcium hydroxide antimicrobial effect and enhances its penetrability.

OBJECTIVES: The objective of the present work was to evaluate the ultrasonic agitation, time and vehicle (propylene glycol or distilled water) on the antimicrobial potential and penetrability of calcium hydroxide pastes on infected dentin by means of Confocal Laser Scanning Microscopy (CLSM) and microbiological culture (MC). MATERIALS AND METHODS: Dentin specimens were infected with Enterococcus faecalis using a new contamination protocol of 5 days. The specimens were divided into eight groups and dressed with the pastes for 7 or 15 days: G1) calcium hydroxide (CH) + propylene glycol (prop)/7 days (d), G2) CH + prop/7d + ultrasonic agitation (U), G3) CH + distilled water (dw)/7d, G4) CH + dw/7d + U, G5) CH + prop/15d, G6) CH + prop/15d + U, G7) CH + dw/15d, G8) CH + dw/15d + U. The ultrasonic activation was made for 1 min in both directions with a plain point insert. After medications removal, the images obtained by CLSM showed the viable (green) and dead (red) bacteria with Live and Dead dye. By the MC, the dentinal wall debris obtained by burs were collected for colony counts. For the penetration test, the Rodamine B dye was added to the CH pastes and analyzed by CLSM. RESULTS: The 7 and 15-days CH + prop+U pastes performed better antimicrobial efficacy, followed by the CH + dw+U/15d paste. CONCLUSIONS: All pastes demonstrated better penetration and antimicrobial activity against E. faecalis when agitated with ultrasound, even in periods of up to seven days. The propylene glycol vehicle showed better results. CLINICAL RELEVANCE: Agitation of the dressing that remains for less time inside the root canal can optimize the decontamination of endodontic treatment.

Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal.

To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I-saline; group II-propolis 100 µg/mL; group III-propolis 300 µg/mL; group IV-propolis nanoparticle 100 µg/mL; group V-propolis nanoparticle 300µg/mL; group VI-6% sodium hypochlorite; group VII-2% chlorhexidine. Dentin shavings were collected at 200 and 400 µm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and ß-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm-1 band and an increase in the 870 cm-1 band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.

Effect of different laser types on bonding strength of CAD/CAM-customized zirconia post to root canal dentin: an experimental study.

In clinical dentistry, the strength of bonding zirconia posts to root canal dentinal walls currently needs enhancement, and laser application can be an important contribution owing to its features that accommodate adjustable modifications on dental materials. Herein, the effect of different laser treatments applied to dentin surfaces on the strength of bonding zirconia posts to root canal dentinal walls is evaluated by using the pull-out bond strength test in a laboratory setting. A total of 40 single-rooted permanent mandibular premolar teeth that were freshly extracted were used here. The root canal preparation steps were performed using the crown-down technique. Custom-made zirconia posts were produced using CAD/CAM technology. Prior to the application of resin cement, the internal surfaces of the root canals were irradiated using Nd:YAG, Er:YAG, and KTP lasers. Pull-out tests were performed on each specimen by using a universal testing machine. One-way analysis of variance and Tukey post hoc tests were used to compare the pull-out bond strength data. The bond strengths of the laser-treated specimens were greater than those of the untreated controls (p < 0.05). While the value of the pull-out bond strength after Nd:YAG laser treatment was significantly higher than the values obtained after the applications of the Er:YAG and KTP lasers (p < 0.05), the pull-out bond strength after Er:YAG laser treatment was considerably greater than that after KTP laser treatment (p < 0.05). The bond strength between the root canal dentin and the CAD/CAM custom-made zirconia post was improved upon using all the laser modalities in current laboratory settings, among which, application of the Nd:YAG laser was the most successful.

The effects of various irrigation protocols on root canal wall adaptation and apical microleakage in primary teeth.

Objective: The objective of this study is to evaluate the wall adaptation and apical microleakage values following the application of various irrigation protocols in primary teeth.Material and methods: For the two parts of the study, extracted upper incisor primary teeth were randomly included to the 1% sodium hypochlorite (NaOCl), 10% ethylenediaminetetraacetic acid (EDTA)+1% NaOCl, 6% citric acid (CA)+1% NaOCl and 0.9% physiological saline (PS) groups. Canal wall adaptation and apical microleakage were assessed by scanning electron microscopy (SEM) and stereomicroscope, respectively.Results: 6% CA + 1% NaOCl group was found to be the most successful irrigation protocol in providing strong canal wall adaptation and less apical microleakage, followed by 10% EDTA +1% NaOCl. 6% CA +1% NaOCl was significantly superior regarding apical microleakage (p < .05).Conclusions: Due to the ability to provide appropriate changes in the root canal walls to make a well-adapted and leak-proof canal filling, 6% CA + 1% NaOCl can be recommended as an irrigation protocol in primary teeth.

Development of Chlorhexidine Digluconate and Lippia sidoides Essential Oil Loaded in Microemulsion for Disinfection of Dental Root Canals: Substantivity Profile and Antimicrobial Activity.

The dental intracanal disinfection is crucial to achieve the success of endodontic treatment, avoiding the maintenance of endodontic infections. Chlorhexidine digluconate can act as an irrigating agent for it. However, it can cause tissue irritation in high concentrations. Therefore, combinations with other antimicrobial agents and more efficient therapeutic alternatives are studied, which make it possible to administer drugs more safely and with minimal adverse effects. Thus, the objective of this study was the development of a microemulsion containing chlorhexidine digluconate and essential oil of Lippia sidoides to be used for disinfection of dental root canals and to evaluate its profile of substantivity and antimicrobial activity. The microemulsions were obtained through phase diagrams, using the spontaneous formation method. We completed a physical-chemical characterization and evaluate the stability of the microemulsions, in addition to the substantivity profile in a bovine root dentin model, and in vitro antibacterial effect on Enterococcus faecalis. A method for quantifying chlorhexidine was developed using UV-Vis spectroscopy. The microemulsions showed acid pH, conductivity above 1.3 µScm-1, and dispersion index similar to water. The microemulsions showed antimicrobial inhibition halos similar to the commercial gel conventionally used, but with four times more substantivity to dentinal tissues. Microemulsions were obtained as a therapeutic alternative to formulations available on the market, presenting themselves as a system with great potential for the administration of drugs for disinfection of root canals.

Sonic irrigant activation for root canal disinfection: power modes matter!

BACKGROUND: Sonic irrigant activation has gained widespread popularity among general dentists and endodontists alike in recent years. This in vitro study aimed to evaluate the impact of three power modes of a sonic activation device (EDDY) on its antimicrobial effectiveness in infected root canals. METHODS: The root canals of straight, human roots (n = 120) were prepared to size 40/.06. In a short-term infection experiment, the root canals were inoculated with different microbial species for three days. The following irrigation protocols, using 4 ml of normal saline as irrigant, were performed: negative control, manual rinsing, sonic irrigant activation at power modes "low", "medium" and "high". In a second, long-term experiment, testing the same irrigation protocols, inoculation lasted 21 days and sodium hypochlorite was used as irrigant. Sequential infection control samples were assessed using culture assays. The statistical analysis included one-way analysis of variance of log10-scaled counts of colony-forming units (CFU) with post-hoc comparisons using Bonferroni corrections and Chi2 tests (α = 0.05). RESULTS: In the short-term experiment, the sonic irrigation protocols decreased the number of CFUs by 1.88 log10 units compared with the negative control (p < 0.001). The power modes "medium" and "high" achieved the most effective reduction of the microbial load. In the long-term experiment, microbial regrowth occurred after 7 days unless the device was used at its highest power setting. CONCLUSIONS: The power modes of the sonic irrigation device have a significant impact on the effectiveness for endodontic disinfection. The sonic irrigation device should always be used at the highest power setting in order to maximize its antimicrobial effectiveness.

The Clinical Effectiveness of Calcium Hydroxide in Root Canal Disinfection of Primary Teeth: A Meta-Analysis.

BACKGROUND The aim of this research was to systematically analyze the effectiveness of calcium hydroxide compared to formocresol (FC) and camphor phenol (CP) in root canal disinfection of primary teeth. MATERIAL AND METHODS The meta-analysis was based on the participants, interventions, control, outcome (PICO) study design principle and 16 randomized-controlled clinical trials published from January 2000 to August 2018. The data heterogeneity of each study was assessed by the Q-test. The odds ratio and 95% confidence interval (CI) were calculated based on the heterogeneity results by Revman software. RESULTS Sixteen randomized-controlled clinical trials of 3047 primary teeth were included in this meta-analysis. There were significant differences of clinical effectiveness between calcium hydroxide and FC in root canal disinfection of primary teeth (OR=3.37; 95% CI range: 2.54-4.48, P<0.01) and endodontic inter-appointment emergencies (EIAE) after disinfection for 7 days (OR=0.26; 95% CI range: 0.16-0.42, P<0.01). However, there was no statistical difference of EIAE, after disinfection of primary teeth for 48 hours, between calcium hydroxide and FC (OR=0.62; 95% CI range: 0.34-1.11, P=0.11). There were significant differences of clinical effectiveness between the calcium hydroxide and CP in root canal disinfection of primary teeth (OR=5.50; 95% CI range: 3.36-8.98, P<0.01). CONCLUSIONS This meta-analysis indicated that the effectiveness of calcium hydroxide as root canal disinfectant in primary teeth was more effective than that of FC and CP.

Bactericidal efficacy of three parameters of Nd:YAP laser irradiation against Enterococcus faecalis compared with NaOCl irrigation.

The success of endodontic treatment depends on the thorough removal of microorganisms from the root canal system. The search for new ways to eliminate the microorganisms is therefore justified. Nd:YAP is a laser that uses yttrium aluminum perovskite, doped with neodymium crystal, as active laser medium. We used the Nd:YAP laser in an in vitro experiment to evaluate the bactericidal effect of three parameters of Nd:YAP laser-activated irrigation on biofilms of Enterococcus faecalis in root canals. The canals of 45 extracted human single-root teeth were prepared on a #35 Mtwo instrument and contaminated with E. faecalis for 14 days. Forty infected single-root teeth were then randomly divided into four groups according to the irrigation agitation protocols as follows: 5.25% sodium hypochlorite (NaOCl), Nd:YAP laser (180 mJ) + NaOCl, Nd:YAP laser (280 mJ) + NaOCl, and Nd:YAP laser (360 mJ) + NaOCl. The remaining bacteria were counted immediately using the cell count method. Teeth were firstly spilt and one half examined by scanning electron microscopy (SEM). The other half involved examination of bacterial colonization in dentinal tubules using confocal laser scanning microscopy (CLSM). Nd:YAP laser (280 mJ) + NaOCl and Nd:YAP laser (360 mJ) + NaOCl completely removed the E. faecalis biofilms from the root canal walls and made it the cleanest among the treatment groups. Bacterial reductions in the treatment groups for dentinal tubules are presented in a descending order as follows: Nd:YAP laser (360 mJ) (53.7%), Nd:YAP laser (280 mJ) (51.5%) > Nd:YAP laser (180 mJ) (45.3%) > 5.25% NaOCl (31.9%) > control (19.3%) (p < 0.05). Nd:YAP laser of 280 mJ and 360 mJ showed effective bactericidal effect in removing E. faecalis biofilm from the root canal walls and dentinal tubules.

Periodontal and endodontic infectious/inflammatory profile in primary periodontal lesions with secondary endodontic involvement after a calcium hydroxide-based intracanal medication.

OBJECTIVE: The aim of the present study was to investigate the effects of a calcium hydroxide-based intracanal medication (ICM) on periodontal and endodontic infectious/inflammatory contents and on periodontal clinical parameters in teeth with primary periodontal lesion and secondary endodontic involvement. MATERIALS AND METHODS: Ten patients with abnormal pulp test results and deep probing depth derived from primary periodontal disease with secondary endodontic involvement were included. Samples were collected from root canals (RC) and periodontal pockets (PP) in order to investigate the microbiological status, levels of endotoxin (LPS), cytokines, and matrix metalloproteinases (MMP), before and after ICM. PCR was used for microbiological assessment. The kinetic-chromogenic LAL assay was used for LPS quantification. Quantikine ELISA kits were used for measurement of IL-1 α, IL-1 ß, TNF-α, PGE2, MMP-2, MMP-3, MMP-8, MMP-9, and MMP-13 levels. The statistical analyses were made using the Friedman and Wilcoxon tests (p < 0.05). T test was used to compare data on periodontal characteristics. RESULTS: ICM did not reduce the number of microorganisms in PP and RC, except for Fusobacterium nucleatum in RC. There was a significant reduction in LPS, MMPs, IL-1 ß, and TNF-α levels in PP after ICM. In RC, LPS, MMP13, PGE2, and IL-1ß levels remained unaltered (p > 0.05); however, the levels of the other MMPs and cytokines were reduced (p < 0.05). After 1 year of the root canal treatment, tooth mobility was significantly reduced (p ≤ 0.05). CONCLUSIONS: The use of a calcium hydroxide-based ICM showed positive effects for periodontal treatment prognosis, as it reduced LPS, cytokine, and MMP levels in periodontal pockets. CLINICAL SIGNIFICANCE: Patients presenting deep probing depth and undergoing periodontal treatment for at least 6 months, with no positive response to periodontal therapy, might benefit with the endodontic treatment.

The effect of different irrigation protocols on smear layer removal in root canals of primary teeth: a SEM study.

OBJECTIVE: The purpose of this study was to compare the efficacy of different irrigation protocols on smear layer removal in root canals of primary teeth by scanning electron microscopy (SEM). MATERIAL AND METHODS: The study was conducted with 40 extracted maxillary primary incisor teeth divided into four groups (n = 10) as 1% sodium hypochlorite (NaOCl), 10% ethylenediaminetetraacetic acid (EDTA)+1% NaOCl, 6% citric acid (CA)+1% NaOCl, and 0.9% physiological saline (PS). After the irrigation procedures, root canal walls were examined by SEM and the efficacies of irrigation solutions in smear layer removal were scored and compared. Data were analyzed using Kruskal-Wallis, Friedman and Siegel Castellan tests. RESULTS: The smear layer removal was found to be statistically more effective in groups of 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl when compared with the other groups (p < .05). Smear removal efficacy was statistically significantly higher in coronal and medium thirds when compared with the apical regions in the experimental groups. CONCLUSIONS: It was concluded that 10% EDTA + 1% NaOCl and 6% CA + 1% NaOCl could be alternative irrigation protocols regarding smear layer removal. However, due to the absence of erosive dentinal changes, it might be suggested that using 6% CA + 1% NaOCl can be recommended compared to 10% EDTA + 1% NaOCl in primary root canals.

Assessment of antibacterial activity of 2.5% NaOCl, chitosan nano-particles against Enterococcus faecalis contaminating root canals with and without diode laser irradiation: an in vitro study.

Objective: This study was done to evaluate the antibacterial effect of chitosan nano-particles (CNPs) root canal irrigant as a new alternative to Sodium hypochlorite (NaOCl) for disinfection of root canals inoculated with Enterococcus faecalis, with and without laser activation.Methodology: Sixty single rooted human premolars were decoronated, prepared and had their apical foramina sealed. E. faecalis were incubated in the root canals for 15 days. The teeth were then randomly divided into two experimental groups (n = 30) according to the disinfection protocol used. In Group I: disinfection was performed using the irrigant solutions only (Saline, 2.5% NaOCl, CNPs). Whereas in Group II, disinfection was done using the same irrigants followed by Diode laser at (980-nm) at 2 W output for 5 × 5 s. Intra-canal bacterial samples were taken before and after canal disinfection to determine the CFU count.Results: In group I, 2.5% NaOCl was as effective as CNP in eradication and significantly more effective than Saline (p = 0.008) in eradication of E. faecalis. In Group II, either 2.5% NaOCl or CNP in combination with diode laser irradiation showed a similarly high effect in bacterial eradication.Conclusions: Within the parameters used in this study, a combination therapy consisting of irrigation followed by diode laser irradiation should be utilized as an effective treatment modality for eliminating E. faecalis from root canal systems.

Evaluation of SmearOFF, maleic acid and two EDTA preparations in smear layer removal from root canal dentin.

Objectives: To evaluate SmearOFF, 7% maleic acid (MA) and two different preparations of ethylenediaminetetraacetic acid (EDTA) in smear layer removal.Materials and methods: Fifty single-rooted teeth were separated into five groups, instrumented and irrigated as follows: (1) SmearOFF, (2) 7% MA, (3) 18% EDTA (pH 11.4), (4) 17% EDTA (pH 8.5) and (5) 0.9% saline. Teeth samples were blinded and examined by scanning electron microscopy with Image J software.Results: Eighteen percent EDTA was less efficient when compared to SmearOFF and MA at all thirds of the root canal system. There was no difference between SmearOFF and MA in the coronal and middle thirds. In the apical third, MA removed more smear layer. Seventeen percent EDTA was as efficient as SmearOFF and MA in coronal and middle third but not in the apical third. Eighteen percent EDTA removed smear layer less efficiently in the coronal and middle thirds than 17% EDTA; in the apical third, there was no difference observed. In the saline group, all specimens were heavily smeared. There was no significant difference between 18% EDTA and saline at all canal thirds.Conclusions: SmearOFF and 17% EDTA (pH 8.5) had better smear layer removal capability in the coronal and middle thirds of the root canal system. In the apical third, 7% MA was superior. 18% EDTA (pH 11.4) and saline had poor smear layer removal ability.

The effect of different irrigation protocols on elastic modulus of dentine and biomechanics of single-rooted premolar tooth: A nano-indentation and finite element analysis study.

AIM: This study evaluated the effect of different irrigation protocols on elastic modulus and biomechanics of single-rooted premolar tooth using with nano-indentation and finite element analysis (FEA). MATERIALS AND METHODS: Root canals of single-rooted human teeth were prepared, divided into eight groups, and irrigated with (1) 2.5% NaOCl + 17% EDTA; (2) 2.5% NaOCl + 17% EDTA + 2.5% NaOCl; (3) 2.5% NaOCl + SmearClear; (4) 2.5% NaOCl + 2% chlorhexidine; (5) 1.3% NaOCl + MTAD; (6) 5.25% NaOCl; (7) 17% EDTA; and (8) saline. The roots were vertically sectioned, and elastic modulus of the root dentine was measured using nano-indenter device at coronal, middle, and apical third. Data were recorded as megapascal and statistically analyzed (one-way analysis of variance, Tukey tests). Three-dimensional FEA model of a premolar tooth was created, and the inner root dentine was modified to simulate the effect of irrigation protocols on root dentine. The elastic properties of inner root dentine layer in the FEA models were modified for each group according to the data obtained with nano-indentation. A 300-N load was applied at the buccal cusp and central fossa of the models with a 45° angle. The stresses were calculated using von Mises stress criteria. RESULTS: All irrigation protocols affected the elastic modulus of root dentine. Groups 2 and 3 showed similar elastic modulus values (P > 0.05), whereas the lowest values were obtained in group 7 (P < 0.05). No statistically significant differences were found between groups 4, 5, and 8 (P > 0.05). CONCLUSION: Despite the effect of different clinically used irrigation protocols on elastic modulus of the inner dentine, this does not affect the biomechanics of the roots.

Antimicrobial photodynamic therapy (light source; methylene blue; titanium dioxide): Bactericidal effects analysis on oral plaque bacteria: An in vitro study.

BACKGROUND: Incomplete eradication of plaque bacteria from the plaque retentive sites and the emerging problem of antibiotic resistance led the scientific community to explore new antimicrobial strategies for improved results and shun antibiotic resistance. OBJECTIVE: The purpose of this in-vitro study was to evaluate the antimicrobial effect of a novel light based therapy and to assess the susceptibility of oral plaque bacteria to light based technologies with and without photosensitizers. MATERIALS AND METHODS: Four oral plaque bacterial strains were isolated from the dental plaque sample collected from the patients and exposed to various light based technologies and photodynamic therapy (PDT) with and without photosensitizers. The cultures were analysed for viable colony forming unit (CFU) counts. One-way analysis of variance was used to statistically analyse differences and the Student-Newman-Keuls method to perform multiple comparison procedures. RESULTS: All groups showed remarkable reduction in the CFUs as compared to control group with use of light based technologies and PDT in this study. The difference of antimicrobial effect between all tested groups either with light based technologies and PDT with control group showed significant reduction in CFUs. CONCLUSIONS: From the results of this study, we concluded that light based technologies and PDT could be a valuable alternative therapy to mechanical debridement in the prevention of growth and recolonisation of oral plaque bacteria.

The efficacy of supplementary sonic irrigation using the EndoActivator® system determined by removal of a collagen film from an ex vivo model.

AIM: To evaluate the efficacy of sonic irrigation (EndoActivator® ) using various polymer tips and power settings in a stained collagen ex vivo model. METHODOLOGY: The root canals of fifty human, straight single-rooted extracted teeth were prepared to size 40, .08 taper. The roots were split longitudinally; stained collagen applied to the canal surfaces, photographed and re-assembled. The canals were subjected to syringe without supplementary (group 1, n = 10) or with supplementary sonic (groups 2-5, n = 10) irrigation. EndoActivator® tip sizes (size 15, .02 taper for groups 2 and 3; size 35, .04 taper for groups 4 and 5) and power settings (low for groups 2 and 4; high for groups 3 and 5) were tested. After irrigation, the canals were re-photographed and the area of residual stained collagen was quantified using the UTHSCA Image Tool program (Version 3.0). The data were analysed using Wilcoxon signed rank test and general linear mixed models. RESULTS: Supplementary sonic irrigation using EndoActivator® resulted in significantly (P < 0.0001) less residual collagen compared with syringe irrigation only. Agitation of irrigant using the large EndoActivator® tip with high power resulted in significantly less (22.4% - 29.5%) residual collagen compared to other combinations (large tip/low power P = 0.001; small tip/low power P = 0.01; small tip/high power P = 0.04). There was no significant difference amongst the latter three groups (P > 0.5). CONCLUSIONS: Supplementary sonic irrigation using the EndoActivator® system was significantly more effective in removing stained collagen from the canal surface than syringe irrigation alone. EndoActivator® used with large tip (size 35, .04 taper) and high power setting in size 40, .08 taper canals was more effective than other combinations.

Release of TGF-ß1 into root canals with various final irrigants in regenerative endodontics: an in vitro analysis.

AIM: To investigate the release of growth factors into the root canal space after various final irrigants during regenerative endodontic procedures. The residual cytotoxic effect of final irrigants on stem cells from the apical papilla (SCAP) was also examined. METHODOLOGY: To measure the release of TGF-ß1, root segments (8 mm long) were irrigated with 1.5% NaOCl followed by 20 mL of final irrigants; Saline, 17% EDTA, 10% citric acid, 10% or 37% phosphoric acid. Specimens were then immersed into culture medium for 24 h and the supernatants were collected to measure TGF-ß1 by ELISA. For the cytotoxicity of residual final irrigants, dentine chips (5 × 5 × 1 mm) treated with irrigants as above were placed in the upper chamber of transwell system. Stem cells from the apical papilla were incubated indirectly in the lower chamber for 24 h and MTS assay was performed after 24 h. The surfaces of irrigated root canals were examined for smear layer with a scanning electron microscope (SEM). Log transformation was performed for ELISA data to compare different groups (one-way ANOVA, α = 0.05). RESULTS: Ten percent citric acid released the greatest amount of TGF-ß1 amongst all groups, which was significantly different to 17% EDTA (P < 0.01). All dentine chips irrigated with the irrigants showed no significant difference of cytotoxicity on SCAP compared to nonirrigated dentine (P > 0.05). SEM revealed completely open dentinal tubules in 10% citric acid, whereas 17% EDTA was associated with partially open dentinal tubules. CONCLUSIONS: Ten percent citric acid was effective as a final irrigant for releasing TGF-ß1 with good biocompatibility in regenerative endodontics.

Effects of a Peganum harmala (Zygophyllaceae) preparation for root canal disinfection.

The aim of this study was to determine the antimicrobial capacity, minimum inhibitory concentration (MIC), and cytotoxic effects of a Peganum harmala seed extract in comparison to 5.25% sodium hypochlorite (NaOCl). The oral pathogen Enterococcus faecalis was used to evaluate the antimicrobial capacity, and the MIC values were determined through serial dilution. Inhibition zones were measured in millimeter, and the data were analyzed statistically by analysis of variance and the Tukey HSD test. For cytotoxicity testing, P. harmala seed extract and 5.25% NaOCl solution were incubated with L929 fibroblast cells. After 1, 24, and 72 hr of incubation, cells were stained and the optical density determined with an enzyme-linked immunosorbent assay (ELISA) reader. Data were analyzed with Chi-Square statistical test. The significance level was set at p < .05. There was no significant difference between the antimicrobial capacity of 5.25% NaOCl and the P. harmala extract (p > .05; MIC 4 µg/ml). The Microculture Tetrazolium (MTT) assay test showed that the cytotoxic effects of the P. harmala extract were significantly lower than 5.25% NaOCl (p < .05). The results show that 5.25% NaOCl and P. harmala seed extract have similar antimicrobial activity against Enterococcus faecalis; but P. harmala, which shows reduced cytotoxicity, should be considered for further investigation as a safe, phytotherapeutic, intracanal irrigant.

Resistance to vertical root fracture of apicoected teeth using different devices during two root canal irrigation procedures.

The aim of the present work was to measure the fracture resistance of endodontically treated teeth that were apicoected with different procedures. Seventy-two extracted human maxillary anterior teeth were included in this study. The specimens were randomly assigned to three main groups according to the apical surgery procedures and then two subgroups according to the irrigation protocols during root canal treatment and total of six groups were obtained (n = 12). Group 1: served as a control and apical surgery process was not performed in this group. Group 2: apical surgery process was performed with tungsten carbide fissure bur Group 3: apical surgery process was performed with Er:YAG laser. Subgroup a: In this group, the specimens were irrigated with %5 NaOCl. Subgroup b: 15% EDTA solution was filled into the root canal and then agitated using a 1.5 W/100 Hz diode laser. The specimens were filled and mounted in acrylic resin blocks and compression strength test was performed. Statistical analysis was performed using two-way ANOVA. The statistical analysis revealed that there were no statistical significant differences between apical surgery procedures (groups 1, 2, and 3) (p < 0.05). Apical resection procedures did not affect the fracture resistance Significant differences were determined between the subgroups (p < 0.05). Agitation of the EDTA with the diode laser reduced the fracture resistance of the specimens. The different canal irrigation techniques altered resistance to fracture; however, apical surgery procedures did not altered the resistance to fracture when compared with the control group.

Bactericidal effect of a diode laser on Enterococcus faecalis in human primary teeth-an in vitro study.

BACKGROUND: In recent years, the diode laser (810 nm) has been used for root canal disinfection, which plays an important role in endodontic therapy. This study was undertaken to evaluate the disinfecting ability of a diode laser in experimentally infected root canals of primary teeth. METHODS: Human retained mandibular primary anterior teeth without apical foramen resorption were selected and contaminated with Enterococcus faecalis for 21 days. The specimens were randomly divided into four groups: the negative group (no treatment), positive group (5.25% NaOCl), diode laser group (diode laser), and diode-NaOCl group (diode laser combined with NaOCl). The disinfecting abilities of the treatments were measured by the numbers of bacteria, scanning electron microscopy and confocal laser microscopy (live-dead staining). RESULTS: Eighty teeth were selected. After irradiation and irrigation, the elimination of bacteria and the smear layer in the laser groups and positive group were significantly superior, compared with the negative group (p < 0.01). In the diode-NaOCl group, bacterial reduction reached nearly 100% on the surfaces of root canals; live bacteria were rarely observed, even in deeper dentinal tubules. CONCLUSION: Use of a diode laser, especially in combination with NaOCl, was effective for disinfecting infected root canals of primary teeth.