Comparative effectiveness of preemptive administration of ibuprofen and ibuprofen-arginine on the anesthetic success of inferior alveolar nerve block in teeth with symptomatic irreversible pulpitis - A double-blind randomized clinical trial.

OBJECTIVES: This study examined the impact of premedication with ibuprofen and ibuprofen-arginine and the influence of preoperative pain and anxiety on inferior alveolar nerve block (IANB) efficacy in cases of symptomatic irreversible pulpitis. MATERIALS AND METHODS: The study involved 150 SIP patients who were randomly assigned to receive ibuprofen (600 mg), ibuprofen-arginine (1,155 mg), or a placebo 30 min before IANB. Preoperative anxiety and pain levels were assessed using the Modified Dental Anxiety Scale and the Heft-Parker visual scale. IANB efficacy was determined by the absence of or mild pain during the procedure. Statistical analysis included chi-square, z-tests, Analysis of Variance, and Student's t tests. RESULTS: The ibuprofen and ibuprofen-arginine groups exhibited significantly higher IANB success rates (62% and 78%, respectively) compared to the placebo group (34%). However, no significant difference was observed between the ibuprofen and ibuprofen-arginine groups. Patients with successful IANB in the ibuprofen and ibuprofen-arginine groups displayed lower median anxiety scores (8) than those with failed blocks (15) and lower mean preoperative pain scores (118.3). CONCLUSION: In cases of symptomatic irreversible pulpitis the preemptive medication with ibuprofen-arginine effectively increased the efficacy of the inferior alveolar nerve block The inferior alveolar nerve block efficacy was influenced by preoperative anxiety levels and the intensity of pain. CLINICAL RELEVANCE: This research underscores the potential benefits of oral premedication with ibuprofen and ibuprofen-arginine in improving anesthesia outcomes in cases of symptomatic irreversible pulpitis.

Impact XP-endo finisher on the 1-year follow-up success of posterior root canal treatments: a randomized clinical trial.

OBJECTIVE: To evaluate the clinical relevance of using the XP-endo Finisher as a supplementary tool to improve the success of root canal treatment of posterior teeth with apical periodontitis, as assessed by 1-year follow-up. METHODS: A randomized clinical trial was conducted with 92 posterior teeth with apical periodontitis. Root canal treatment was performed using a single reciprocating file, with or without the supplementary use of the XP-endo Finisher. The status of apical periodontitis was assessed using the periapical index (PAI) at baseline and 1 year follow-up. Changes on PAI indicated that the lesions were healed, healing, or not healed. Successful treatments were defined as healed or healing lesions without clinical symptoms. Chi-square analysis and logistic regression were used for data analysis (α = 0.05). RESULTS: There was no significant difference in the distribution of healing status between the XP-endo Finisher group and the control group (p = 0.690). The success rates were also similar, with 81% in the XP-endo Finisher group and 78% in the control group. However, gender had a significant impact on success rates, with higher rates observed in females. CONCLUSIONS: The use of the XP-endo Finisher file as a supplementary tool did not affect the success rate of root canal treatment in posterior teeth with apical periodontitis. The findings indicate that the XP-endo Finisher file has limited clinical relevance in improving treatment outcomes for root canal treatment in posterior teeth with apical periodontitis. CLINICAL TRIAL REGISTRATION: The study protocol was registered in the Brazilian Clinical Trials Registry under identification number RBR-76w7cj (June 19, 2018).

Development and validation of a method for creating incomplete vertical root fracture in extracted teeth.

The present study reported a method for inducing incomplete root fracture in human extracted teeth for the purpose of evaluating the merits of different diagnostic imaging techniques. Thirty-five single-rooted teeth were inspected under magnification and transillumination to exclude previously fractured teeth. Tooth crowns were removed, and the root canals were prepared up to the ProTaper Next X4 (40.06) file. Each root was lined with wax and embedded in a polystyrene resin block. The setup was attached to a universal testing machine for pressing a customized conical wedge (diameter at tip: 0.6 mm; taper: 0.2 mm/mm) into the instrumented canal with a 2 kN load at 5 mm/min. The machine was programmed to stop after a sudden 10% drop in loading force. Each specimen was removed from the resin block and inspected under × 20 magnification and transillumination to identify the fracture characteristics (pattern, surfaces and root-third affected). The gap width of each specimen was measured at different locations along the fracture line. The protocol induced incomplete vertical root fractures in all specimens. Fracture widths were < 100 µm in all specimens (mean gap width: 34.9 µm). The proposed methodology was successful in inducing incomplete vertical root fractures with characteristics that resemble the clinical presentation of these conditions. The method is easy to execute, highly reproducible and helps to minimize bias in laboratory studies that aims to mimic vertical root fractures.

Dentin thickness as a risk factor for vertical root fracture in endodontically treated teeth: a case-control study.

OBJECTIVES: This study evaluated factors associated with vertical root fracture in endodontically treated teeth, using a cone-beam computed tomography (CBCT) image database. MATERIALS AND METHODS: The sample for this case-control study consisted of 81 CBCT scans of teeth with vertical root fracture (VRF) and 81 CBCT scans of non-fractured teeth, matched by age, sex, and tooth position. The analyzed variables included dentin thickness, an intraradicular post, an adjacent implant, and a missing adjacent tooth. Student's t test test was used to compare the quantitative variables. The chi-square test was used to compare the categorical variables. Logistic regression was performed to evaluate the association between the presence of VRF and the independent factors assessed. RESULTS: The mean dentin thickness of fractured teeth was 1.3 mm, whereas that of non-fractured ones was 1.5 mm (p < 0.001). There was no difference between the fractured and non-fractured groups, regarding implant frequency or missing adjacent tooth (p > 0.05). There were a significantly larger number of teeth with posts in the fractured versus non-fractured group (p = 0.007). However, dentin thickness ≤ 1.3 mm was the only factor associated with VRF in the multiple regression model (OR = 3.60, 95%CI = 1.76-7.37). CONCLUSIONS: Dentin thickness may influence the development of VRF. Dentin thickness ≤ 1.3 mm is associated with a greater likelihood of fracture than ≥ 1.4 mm. CLINICAL RELEVANCE: This study suggests there may be a minimum amount of safe dentin thickness that should be preserved after endodontic instrumentation.

Evolution of endodontic medicine: a critical narrative review of the interrelationship between endodontics and systemic pathological conditions.

Endodontics has gained emphasis in the scientific community in recent years due to the increase in clinical and in animal models studies focused on endodontic medicine, which aims to evaluate the interrelationship between systemic and periapical tissues pathological conditions. These studies have shown that systemic changes can boost the pathogenesis of endodontic infection, favoring its development and progression. A contrary relationship is reported in numerous studies that affirm the potential of endodontic infection to trigger systemic damage and may lead to the worsening of pre-existing pathologies. Recently, the potential of filling materials to develop systemic changes such as neurological alterations had been evaluated, also showing that systemic diseases can negatively influence tissue responses to filling materials after endodontic treatment. Despite advances in endodontic medicine studies, there are still gaps in knowledge on the mechanisms of interactions between apical periodontitis (AP) and systemic diseases and much research to be done. In this sense, this critical narrative literature review aimed to show the evolution of studies in endodontic medicine to help the endodontist to know the role of systemic diseases in the pathogenesis of AP and the possible interference in the repair of periapical tissues after endodontic treatment, as well as to evidence the systemic complications that can be triggered or aggravated in the presence of endodontic infection.

Comparison of Dimensions of the Nasopharynx and Oropharynx Using Different Anatomical References: Is There Equivalence?

PURPOSE: To evaluate the equivalence of the volumes obtained using different anatomic references to measure the nasopharynx and oropharynx on cone-beam computed tomography (CBCT) scans. We hypothesized that no variations would be found in the nasopharynx and oropharynx dimensions when measured using different measurement methods. MATERIALS AND METHODS: A total of 40 CBCT scans of patients with skeletal Class I (age range, 20 to 50 years) were measured independently by 2 of us. The nasopharynx and oropharynx subregions were volumetrically measured using the adopted limits of 5 different measurement methods (3 for the nasopharynx and 2 for the oropharynx) and InVivoDental software, version 5.4 (Anatomage, San Jose, CA). The minimum area and the minimum area of localization were also evaluated. The intra- and interexaminer concordance for the measurements from the different methods were verified using the interclass correlation coefficient (ICC). The analysis of variance for repeated measures was used to compare the measurements from the 3 nasopharynx methods. The paired t test was used to compare the measurements from the 2 oropharynx methods. The statistical tests were performed at the 5% significance level using SPSS software, version 22.0 (IBM Corp, Armonk, NY). RESULTS: The intra- and interexaminer ICC values were greater than 0.8. We found a statistically significant difference in the volume measurements among the 3 nasopharynx methods (P = .001). However, no differences were found in the minimum area or minimum area of localization comparisons. Statistically significant differences were also observed for the volume, minimum area, and minimum area of localization between the 2 oropharynx methods (P = .001). CONCLUSIONS: Studies that have used different methods of measurement should not be directly compared. The different measurement methods used for nasopharynx and oropharynx evaluations should not be compared.

Dental trauma on primary teeth at different root resorption stages-A dynamic finite element impact analysis of the effect on the permanent tooth germ.

BACKGROUND/AIM: Dental trauma is a common emergency in children with primary teeth. The aim of this study was to determine stress propagation to the permanent tooth germ and surrounding bone and soft tissues during dental trauma to primary central incisors with three levels of physiological root resorption. MATERIAL AND METHODS: Stresses were determined using finite element analysis (FEA). Cross-sectional models were created using cone-beam computed tomography images of 3.5, 5, and 6 years olds, representing three different physiological root resorption stages of a maxillary primary central incisor. The models included periodontal ligament, bone, and soft tissues. An impact with an asphalt block moving at 1 m/s,was simulated for two impact two directions, frontal on the labial tooth surface, and on the incisal edge. Stresses and strains were recorded during impact. RESULTS: The impact caused stress concentrations in the surrounding bone and soft tissues and permanent tooth germ, regardless of the direction of impact and the primary tooth resorption stage. Impact stresses in dental follicles and surrounding bone increased in models with more physiological root resorption of the primary tooth. Incisal impact generated higher stress concentrations in surrounding bone and soft tissues and permanent tooth germ regardless of physiological root resorption stage. The primary incisor with no physiological root resorption showed high stress concentrations at its root apex. CONCLUSION: During impact to a primary incisor, stresses most significant for potential damage to the formation of permanent enamel and dentin were at the dental follicle and surrounding bone tissue with the three levels of physiological root resorption.

Low-level laser therapy as adjunctive treatment for a sodium hypochlorite accident: a case report.

A 39-year-old woman sought specialized treatment complaining of a large, painful oral ulcer in the right buccal vestibule after receiving emergency endodontic treatment 3 days earlier. The patient reported that the tooth, the mandibular right first premolar, was not isolated with a rubber dam and that she felt the extrusion of a liquid in the buccal tissues. Clinically, a necrotic area with raised erythematous borders was observed in the mandibular right side. The clinical diagnosis was a chemically induced ulcer caused by a sodium hypochlorite accident. Dexamethasone and amoxicillin were prescribed to control pain and prevent secondary infection. The large size of the lesion was an indication for application of low-level laser therapy (LLLT), which was delivered at a wavelength of 685 nm (output power, 30 mW; power density, 0.5 mW/cm2 ; energy density, 6 J/cm2 ) every 2 days for a total of 6 sessions. The LLLT was applied to the necrotic area with a punctual mode (2 points) for 12 seconds per point. The patient reported a substantial reduction in pain after the second application, and the wound was completely healed after 6 sessions. The results observed in this patient suggest that LLLT could aid patients in recovering from NaOCl-related lesions.

Nonconventional Therapeutic Protocol for Type III Dens Invaginatus.

INTRODUCTION: This study discusses a nonconventional therapeutic protocol for type III dens invaginatus. This condition is a disorder of dental development, caused by the invagination of enamel into coronal and/or radicular dentin structure. This promotes several structural alterations within the dental organ, which offers challenges and difficulties to perform the endodontic treatment when needed. This article reports a clinical case where a conservative approach was adopted to preserve the invagi-nated tooth, and endodontic treatment was performed in the main necrotic canal. Following 21 years of observation, a complete root formation could be seen, with dental pulp preservation of the pulpotomized tooth. Considering the reported difficulties for the treatment of dens invaginatus, conservative measures, such as pulpotomy to preserve the remaining dental pulp may be an excellent alternative to allow less invasive procedures, thus avoiding endodontic surgery. This study discusses a nonconventional therapeutic protocol for type III dens invaginatus. A conservative approach adopted preserved the invaginated tooth, and root canal treatment was performed in the main necrotic canal. Following 21 years of observation, there was complete root formation, with dental pulp preservation of the pulpotomized tooth.

Flute and Shank Dimensions of Reciprocating Instruments before and after Simulated Root Canal shaping.

AIM: This study analyzed the effect of the dimensions of the flute and shank in the first 4 mm of instrument tips on the deformation and dimensional changes of reciprocating instruments after root canal shaping (RCS). MATERIALS AND METHODS: The reciprocating instruments used were Reciproc® R25, R40, and R50; WaveOne® Small, Primary, and Large; and Unicone® #20, #25, and #40. Scanning electron microscopy images of the first 4 mm of the tip were acquired at 30× magnification before and after simulated curved root canals were shaped. Each instrument was used only once. The images were transferred to the AxioVision® software to measure the flute area (µm2), shank area (µm2), flute length (µm), and cross-sectional diameter (µm). Student's t test for paired samples was used to compare differences before and after RCS, and analysis of variance followed by the Tukey test, to compare differences between instruments of similar sizes. The instruments were classified according to deformations after RCS. RESULTS: Reciproc® instruments had larger flutes and smaller shanks. The Reciproc® R40 had significant differences in cross-sectional diameter at 0.5 mm from the tip. Reciproc® had no plastic deformations. Unicone® #20 instruments had significant differences in cross-sectional diameter at 1.5 and 3.0 mm from the tip, and #25 instruments had differences at 1.5 and 3.0 mm and in length of the second and third flutes. One #20 and three #40 instruments had plastic deformations. The differences in length of the first and fourth flutes of WaveOne® Primary and in cross-sectional diameter at 2.0 mm from the tip of WaveOne® Large were significant. Two of three WaveOne® Large instruments had plastic deformations. CONCLUSION: Reciproc® instruments had greater flute areas and lengths and smaller shanks than Unicone® and WaveOne® instruments of similar sizes. Reciproc® instruments had a greater flute-to-shank ratio. WaveOne® instruments had the lowest flute-to-shank ratio. Unicone® instruments had the most plastic deformations. Instruments with larger flutes and smaller shanks had fewer plastic deformations after curved RCS. CLINICAL SIGNIFICANCE: The knowledge of mechanical behavior before choosing the endodontic instrument may avoid fracture, regardless of the clinical condition, and it is essential to the success of root canal treatment.

Presence of Metallic Microfragments on Dentinal Walls and Instrument Defects following Root Canal Preparation.

AIM: To determine the presence of metallic microfragments and their elemental composition in the dentinal walls of root canals following preparation using different endodontic instruments and to assess the active cutting edges of instruments with regard to structural defects. MATERIALS AND METHODS: A total of 108 molar teeth were selected and prepared using different endodontic instruments. Teeth were randomly divided into nine groups of 12 teeth each, according to the instruments employed: Manual systems -K-FlexoFile, K-File, and Hedstroem; rotary systems - ProTaper Next, Mtwo, BioRaCe; and reciprocating systems - Reciproc, Unicone, and WaveOne. Both root canals and instruments were assessed using scanning electron microscopy, and the elemental composition of metallic microfragments was determined using energy-dispersive X-ray spectroscopy. RESULTS: Metallic microfragments were found in the groups prepared with both manual and reciprocating instruments, with no statistically significant differences between groups, thirds, or presence of metallic microfragments (p ≥ 0.05). Moreover, all groups presented structural defects in both new and used instruments; however, rotary instruments (ProTaper Next, Mtwo 702, BioRaCe) were the ones with the lowest number of defects, at statistically significant differences in comparison with other instruments (p < 0.05). CONCLUSION: The presence of metallic microfragments on dentinal walls following root canal preparation was associated with manual and reciprocating instrumentation. Furthermore, rotary instruments were the ones with the lowest number of defects. Considering the outcomes measured in this study, rotary instruments performed better than the other two groups, as they were associated with the lowest number of metallic microfragments and structural defects. CLINICAL SIGNIFICANCE: During root canal preparation, operative procedures may induce changes to the root canal shape, as well as the release of metallic fragments resulting from the action of instruments on dentinal walls. Therefore, it is important to determine, among the different techniques used for this purpose, which ones are least susceptible to this occurrence.

Ozone Gas Effect on Mineral Content of Dentin exposed to Streptococcus mutans Biofilm: An Energy-dispersive X-ray Evaluation.

AIM: This study aims to assess the effect of ozone gas on dentin exposed to Streptococcus mutans biofilm by evaluation of mineral content [log calcium-to-phosphorus (Ca/P)] using energy-dispersive X-ray (EDX) spectroscopy. MATERIALS AND METHODS: Five human third molars were sectioned into four slices of dentin and distributed in four groups: I - control (no treatment); II - ozone therapy; III - biofilm development; IV - ozone therapy followed by biofilm development. Mineral content (log Ca/P) was evaluated by EDX. Data were analyzed by analysis of variance and Tukey's test (p < 0.05). RESULTS: Results showed that the mineral content of control group (I) was similar to ozone group (II), and was statistically higher than biofilm (III) and ozone + biofilm (IV). The lowest log Ca/P was determined in biofilm group (III). CONCLUSION: It can be concluded that ozone gas did not grant preventive effects of demineralization by S. mutans biofilm on dentin surface. CLINICAL SIGNIFICANCE: Ozone gas therapy may be an alternative noninvasive treatment aiming to reduce the levels of caries-associated microorganisms. This therapy may, thereby, be an alternative and/or complementary treatment strategy in preventive dentistry.

Correlation of Crown Angulation and Inclination Based on Occlusal, Camper's, and Frankfurt Planes Using Digital Models.

This study provided the measures of crown angulations and inclinations which were evaluated using 3D cephalometry. This study was conducted to demonstrate the relationship between the main planes : Camper's, Frankfurt, and occlusalplanes for guiding the positioning ofthe skull and orthodontic planning.

Cone-beam computed tomography as a diagnostic method for determination of gingival thickness and distance between gingival margin and bone crest.

The objective of the present study was to assess cone-beam computed tomography (CBCT) as a diagnostic method for determination of gingival thickness (GT) and distance between gingival margin and vestibular (GMBC-V) and interproximal bone crests (GMBC-I). GT and GMBC-V were measured in 348 teeth and GMBC-I was measured in 377 tooth regions of 29 patients with gummy smile. GT was assessed using transgingival probing (TP), ultrasound (US), and CBCT, whereas GMBC-V and GMBC-I were assessed by transsurgical clinical evaluation (TCE) and CBCT. Statistical analyses used independent t-test, Pearson's correlation coefficient, and simple linear regression. Difference was observed for GT: between TP, CBCT, and US considering all teeth; between TP and CBCT and between TP and US in incisors and canines; between TP and US in premolars and first molars. TP presented the highest means for GT. Positive correlation and linear regression were observed between TP and CBCT, TP and US, and CBCT and US. Difference was observed for GMBC-V and GMBC-I using TCE and CBCT, considering all teeth. Correlation and linear regression results were significant for GMBC-V and GMBC-I in incisors, canines, and premolars. CBCT is an effective diagnostic method to visualize and measure GT, GMBC-V, and GMBC-I.

Determination of Root Canal Cleanliness by Different Irrigation Methods and Morphometric Analysis of Apical Third.

AIM: The aim of this study was to determine the root canal area before and after the instrumentation 1 mm short of the apical foramen by clinical and cone beam computed tomography (CBCT) methods, and to evaluate the cleanliness of the apical region in mesiodistal flattened teeth by using optical microscopy. MATERIALS AND METHODS: Forty-two human single-canal mandibular incisors were instrumented using the Free Tip Preparation technique up to three, four or five instruments from the initial. Cone beam computed tomography scans were acquired of the samples before and after root canal preparation (RCP). Irrigation was performed by conventional or hydrodynamic means, using 2.5% sodium hypochlorite. The samples were prepared for observation under an optical microscope. Images were digitally obtained, analyzed and the results were submitted to statistical analysis (two-way ANOVA complemented by Bonferroni's post-test). RESULTS: There was no significant difference between the studied anatomical areas with both CBCT and clinical methods. There were no differences between irrigation methods. It was verified differences between instrumentation techniques. Instrumentation with four instruments from the initial instrument determined a significant increase in the contact area when compared to preparation with three instruments, but RCP with 5 instruments did not result in a better cleanliness. CONCLUSION: The analysis with CBCT was not capable to determine the precise shape of surgical apical area comparing to the clinical method. CLINICAL SIGNIFICANCE: Both the conventional and hydrodynamic irrigation techniques were not able to promote root canals debris-free. The instruments action in root canal walls was proportional to the number of instruments used from the initial apical instrument.

Sealing ability of root-end filling materials.

BACKGROUND: The aim of this research was to compare the apical sealing ability of different root-end filling materials (SuperEBA(®), ProRoot MTA(®), thermoplasticized gutta-percha + AH-Plus(®), thermoplasticized RealSeal(®)), by means of microbial indicators. MATERIALS AND METHODS: Thus, 50 human single-rooted teeth were employed, which were shaped until size 5 0, retro - prepared with ultrasonic tips and assigned to 4 groups, retro-filled with each material or controls. A platform was employed, which was split in two halves: upper chamber-where the microbial suspension containing the biological indicators was introduced (E. faecalis + S. aureus + P. aeruginosa + B. subtilis + C. albicans); and a lower chamber containing the culture medium brain, heart influsion, where 3 mm of the apical region of teeth were kept immersed. Lectures were made daily for 60 days, using the turbidity of the culture medium as indicative of microbial contamination. Statistical analyses were carried out at 5% level of significance. RESULTS: The results showed microbial leakage at least in some specimens in all of the groups. RealSeal(®) has more microbial leakage, statistically significant, compared to ProRoot(®) MTA and SuperEBA(®). No significant differences were observed when compared ProRoot(®) MTA and SuperEBA(®). The gutta-percha + AH Plus results showed no statistically significant differences when compared with the other groups. CONCLUSIONS: All the tested materials showed microbial leakage. Root-end fillings with Super-EBA or MTA had the lowest bacterial filtration and RealSeal shows highest bacterial filtration.

Effect of Instrumentation Techniques, Irrigant Solutions and Artificial accelerated Aging on Fiberglass Post Bond Strength to Intraradicular Dentin.

OBJECTIVE: To evaluate the effect of instrumentation techniques, irrigant solutions and specimen aging on fiberglass posts bond strength to intraradicular dentine. MATERIALS AND METHODS: A total of 120 bovine teeth were prepared and randomized into control and experimental groups resulting from three study factors (instrumentation techniques, irrigant solutions, specimen aging). Posts were cemented with RelyX U100. Samples were submitted to push-out test and failure mode was evaluated under a confocal microscope. RESULTS: In specimens submitted to water artificial aging, nickel-titanium rotary instruments group presented higher bond strength values in apical third irrigated with NaOCl or chlorhexi-dine. Irrigation with NaOCl resulted in higher bond strength than ozonated water. Artificial aging resulted in significant bond strength increase. Adhesive cement-dentin failure was prevalent in all the groups. CONCLUSION: Root canal preparation with NiTi instruments associated with NaOCl irrigation and ethylenediaminetetra acetic acid (EDTA) increased bond strength of fiberglass posts cemented with self-adhesive resin cement to intraradicular dentine. Water artificial aging significantly increased post-Clinical significance: The understanding of factors that may influence the optimal bond between post-cement and cement-dentin are essential to the success of endodontically treated tooth restoration.

Chemical and structural characterization of glass ionomer cements indicated for atraumatic restorative treatment.

Glass ionomer cements (GICs) are restorative materials, which clinical use has increased significantly during the last decade. The aim of the present study was to analyze the chemical constitution and surface morphology of four glass ionomer cements: Maxxion R, VitroFill, Vidrion R and Vitremer. Twelve polyethylene tubes with an internal diameter of 3 and 3 mm in length were prepared, filled and then transferred to a chamber with 95% relative humidity and a temperature of 37°C. The surface morphology of the tested materials was examined by scanning electron microscopy (SEM) and main components were investigated by energy-dispersive X-ray microanalysis (EDX). Scanning electron microscopy revealed irregular and rough external surface. Cracking was not observed. The main constituents were found to be aluminum, silicon, calcium, sodium and fluoride. Phosphorus, sulfur and barium were only observed in Vidrion R, while chlorine were only observed in Maxxion R. Elemental mapping of the outer surface revealed high concentration of aluminum and silicon. Significant irregularities on the surface of the tested materials were observed. The chemical constitution of all GIC was similar.

Antibacterial Potential of 2.5% Sodium Hypochlorite in Distinct Irrigation Protocols on Enterococcus faecalis Biofilm.

OBJECTIVE: The aim of this study was to evaluate the effect of irrigation methods on antibacterial potential of 2.5% NaOCl on Enterococcus faecalis biofilm. MATERIALS AND METHODS: Enterococcus faecalis biofilms were prepared during 60 days on 48 human root canals and randomized into control and experimental groups using positive and negative pressure irrigation. Bacterial growth was analyzed using turbidity of culture medium followed by UV spectrophotometry, and scanning electron microscopy (SEM) analyses were performed. Mean and standard deviations were used for evaluate the mean optical densities associated to the number of bacteria present culture, and Scheirer-Ray-Hare (an extension of the Kruskal-Wallis test) and Tamhane test to analyze the SEM images in the groups and thirds. Significance was set at 5%. RESULTS: Enterococcus faecalis was still present after root canal cleaning regardless of irrigation methods or bacterial identification methods. CONCLUSION: Positive and negative pressure irrigation protocols using 2.5% NaOCl show a similar capacity to reduce E. faecalis in infected root canals.

Determination of chemical components derived from 2% chlorhexidine gel degradation using gas chromatography-mass spectrometry.

OBJECTIVE: This study determined the chemical components derived from degradation of 2% chlorhexidine (CHX) gel and solution by using gas chromatography-mass spectrometry. MATERIALS AND METHODS: Three 2% CHX gels were used to identify the products of CHX gel degradation using gas chromatography-mass spectrometry. A solution of CHX was also evaluated to compare the degradation between gel and solution. Degradation was evaluated in four storage situations (on the worktable with light: on the worktable without light; in the Pasteur oven at 36.5°C without light; and in the refrigerator at 8°C without light). Measurements were made at four time points: initial analysis and 1, 3 and 6 months after. The conversion of CHX into para-chloroaniline in storage situations and in different periods was analyzed statistically using chi-square test (α = 5%). RESULTS: The 2% CHX gel or solution had already degraded vial found within the period of validity, at all time points and for all storage conditions. The amount of para-chloroaniline (pCA) was directly proportional to time in the case of CHX solution, but not in CHX gel due to lack of homogeneity. CHX homogeneity in hydroxyethylcellulose gel was directly dependent on compounding mode. CONCLUSIONS: Degradation products, such as para-chloroaniline (pCA), orto- chloroaniline (oCA), meta-chloroaniline (mCA), reactive oxygen species (ROS) and organochlorines (ortho-chlorophenyl isocyanate and 2-amino-5-clorobenzonitrila) were found in 2% CHX gel and solution, regardless of storage conditions or time. In relationship to gel homogenization an alternative to produce 2% CHX gel and a new homogenization method have been developed.