Discus Dental Research Articles

The Effect of Apical Positive and Negative Pressure Irrigation Methods on Postoperative Pain in Mandibular Molar Teeth with Symptomatic Irreversible Pulpitis: A Randomized Clinical Trial

IntroductionThis study compared the effect of conventional needle irrigation (positive pressure) and the EndoVac system (Discus Dental, Culver City, CA) (negative pressure) on postoperative pain in mandibular molar teeth with symptomatic irreversible pulpitis. MethodsOne hundred sixteen patients with symptomatic irreversible pulpitis were selected. Teeth were randomly assigned to 2 groups according to the irrigation methods performed during root canal preparation. In group 1, root canal irrigation was performed using a syringe and a 31-G side-port needle (NaviTip; Ultradent, South Jordan, UT). In group 2, the EndoVac system was used for irrigation. Teeth were then obturated with gutta-percha and a resin-based sealer using the cold lateral compaction technique. The presence of postoperative pain was assessed after 6, 24, 48, and 72 hours and 1 week. ResultsAt 6-, 24-, and 48-hour time intervals, group 1 patients reported more intense postoperative pain than patients in group 2 (P < .05). There was no significant difference between the 2 groups at the other time intervals (P > .05), and in both groups the intensity of postoperative pain decreased over time. ConclusionsApical positive pressure irrigation caused greater postoperative pain after endodontic therapy of mandibular molar teeth with symptomatic irreversible pulpitis compared with the apical negative pressure irrigation system.

Supplementary Steps for Removing Hard Tissue Debris from Isthmus-containing Canal Systems

IntroductionThe purpose of this ex vivo study was to evaluate the percentage reduction of accumulated hard tissue debris (AHTD) in the mesial root canal system of mandibular molars under different final irrigation regimens by means of micro–computed tomographic imaging. MethodsSixty curved mesial roots of mandibular molars with 2 independent canals joint apically by an isthmus (Vertucci type II) were selected. Specimens were scanned at a resolution of 12.5 μm, anatomically matched, and distributed into 3 groups (n = 20) according to the preparation protocol: Self-Adjusting File (SAF; ReDent Nova, Ra'anana, Israel), Reciproc (VDW GmbH, Munich, Germany), and Revo-S (Micro-Mega, Besançon, France) systems. Then, each group was subdivided into 2 subgroups (n = 10) according to the final irrigation protocol with the SAF or EndoVac system (Discus Dental, Culver City, CA). The percentage volume and percentage reduction of AHTD after root canal preparation and final irrigation protocols were statistically compared using 1-way analysis of variance, the paired sample and the independent Student's t tests. The level of significance was set at 5%. ResultsWithin groups, the mean percentage volume was significantly reduced after the final irrigation procedures in either the SAF (from 1.52%–1.78% to 1.01%–1.20%) or EndoVac (from 2.11%–2.23% to 1.31%–1.52%) subgroups (P < .05). In the experimental groups, the mean percentage reduction of AHTD ranged from 29.15%–39.90% after the irrigation protocols, with no statistical difference between groups (P > .05). ConclusionsNone of the irrigation approaches succeeded in rendering the mesial root canal system free of AHTD. A similar percentage reduction of AHTD was achieved after final irrigation protocols using either the SAF or EndoVac system.

Stain removal effect of novel papain- and bromelain-containing gels applied to enamel.

The aims of the study are to prepare novel stain removal gel-based formulations containing papain or bromelain and to investigate their stain removal effect when applied to enamel. Experimental bromelain- and papain-based stain removal gels were prepared. Next, enamel/dentin tooth samples (6×6mm2, 4mm in thickness) were obtained from bovine teeth, stained in coffee solution for 1week, and measured with a digital spectrophotometer (Easyshade, Vita Zahnfabrik) for color assessment (baseline). The samples were then randomly allocated into four groups (n=7), according to the stain removal agent applied: ContrastPM+ (Discus Dental, LLC), which is based on 20wt.% carbamide peroxide (positive control); bromelain-based; papain-based; and no agent (negative control). The materials were applied once a week, three times per day, during 4weeks, and following the directions of use from positive control. The samples were measured again with the Easyshade and using the CIEL * a * b * color system. The color change (ΔE *) results were obtained by subtracting the baseline values from the final color values obtained at each time point. The data were statistically analyzed using two-way repeated-measures analysis of variance and Student Newman Keuls's test as a post hoc test (α=5%). All stain removal agents produced greater color change than the negative control (p<.001), with the positive control demonstrating greater ΔE * values when compared to the experimental gels (p≤.004). The second application of all gels resulted in greater ΔE * values compared to the first application (p≤.025), although no color change was observed after the third application (p≥.051), regardless of the material evaluated. The proposed gels containing proteolytic enzymes (bromelain or papain) of vegetal origin may hold significant clinical potential as active agents for the preparation of stain removal agents free of hydrogen/carbamide peroxide.

Effect of tooth-bleaching agents on phosphate concentration in dental enamel by means of Raman spectroscopy

ObjectiveTo analyze concentration of phosphate ν1 molecule in dental enamel by means of Raman spectroscopy after applying dental bleaching materials at different concentrations. Methodology30 recently extracted human teeth were selected. Teeth were free of caries and pigmentations. Raman specters were obtained from each tooth before application of bleaching agents. Specimens were divided into three experimental groups according to the chemical activation of the used bleaching material concentration (Day White®, Discus Dental). Group 1: 9.5% hydrogen peroxide, group 2: 14% hydrogen peroxide, and group 3: 38% hydrogen peroxide. With a Raman spectroscope ν1 phosphate molecule concentration was measured in the dental enamel before application as well as at second and fourth week of bleaching procedure. For repetitive measurements (p ≤ 0.05) ANOVA variance analysis was conducted. ResultsIn experimental groups 2 and 3 (p ≤ 0.05), a decrease in concentration of phosphate ν1 molecule was observed during treatment execution and at treatment completion group 1 did not reveal statistically significant reduction. ConclusionsWithin the limitations inherent to the present study, it was possible to conclude that the bleaching agent caused loss of concentration of the phosphate ν1 molecule. This loss was greater in higher concentration bleaching procedures.

Efecto de agentes de blanqueamiento dental sobre la concentración de fosfato en el esmalte dental por medio de espectroscopia Raman

Objective: To analyze concentration of phosphate ν1 molecule in dental enamel by means of Raman spectroscopy after applying dental bleaching materials at different concentrations. Methodology: 30 recently extracted human teeth were selected. Teeth were free of caries and pigmentations. Raman specters were obtained from each tooth before application of bleaching agents. Specimens were divided into three experimental groups according to the chemical activation of the used bleaching material concentration (Day White®, Discus Dental). Group 1: 9.5% hydrogen peroxide, group 2: 14% hydrogen peroxide, and group 3: 38%hydrogen peroxide. With a Raman spectroscope ν1 phosphate molecule concentration was measured in the dental enamel before application as well as at second and fourth week of bleaching procedure. For repetitive measurements (p ≤ 0.05) ANOVA variance analysis was conducted. Results: In experimental groups 2 and 3 (p ≤ 0.05), a decrease in concentration of phosphate ν1 molecule was observed during treatment execution and at treatment completion group 1 did not reveal statistically significant reduction. Conclusions: Within the limitations inherent to the present study, it was possible to conclude that the bleaching agent caused loss of concentration of the phosphate ν1 molecule. This loss was greater in higher concentration bleaching procedures.

Micro–Computed Tomographic Evaluation of Hard Tissue Debris Removal after Different Irrigation Methods and Its Influence on the Filling of Curved Canals

IntroductionThe aim of this study was to compare the efficacy of passive ultrasonic irrigation (PUI) and the EndoVac (EV) System (Discus Dental, Culver City, CA) in hard tissue debris removal and its influence on the quality of the root canal filling with the aid of micro–computed tomographic scanner. MethodsTwenty-four mandibular molars were subjected to 4 microtomographic scannings (ie, before and after instrumentation, after final irrigation, and after obturation) using the SkyScan 1176 X-ray microtomograph (Bruker microCT, Kontich, Belgium) at a resolution of 17.42 μm. Mesial canals were prepared using R25 Reciproc instruments (VDW GmbH, Munich, Germany) and divided into 2 groups according to the final irrigation method: the PUI group (n = 12) and the EV group (n = 12). All specimens were filled with the continuous wave of condensation technique. CTAn and CTvol software (Bruker microCT) were used for volumetric analysis and 3-dimensional model reconstruction of the root canals, hard tissue debris, and the filling material. Data were statistically analyzed using the Student t test. ResultsAnalysis of the micro–computed tomographic scans revealed debris accumulated inside the root canals, occupying an average of 3.4% of the canal's volume. Irrigation with PUI and the EV system reduced the volume of hard tissue debris in 55.55% and 53.65%, respectively, with no statistical difference between them (P > .05). Also, there was no difference among the groups with regard to the volume of filling material and voids (P > .05). ConclusionsPUI and the EV system were equally efficient in the removal of hard tissue debris and the quality of root canal filling was similar in both groups, with no influence from the irrigation method.

Comparison of Different Irrigation Activation Regimens and Conventional Irrigation Techniques for the Removal of Modified Triple Antibiotic Paste from Root Canals

IntroductionThe aim of this study was to compare the efficacy of irrigation activation regimens and conventional syringe irrigation technique in the removal of modified triple antibiotic paste (mTAP) from root canal walls. MethodsFifty-six extracted human mandibular premolars were prepared using ProTaper rotary files (Dentsply Maillefer, Ballaigues, Switzerland) up to size F4. The root canals were filled with mTAP medicament, and after 21 days, the roots were randomly assigned to 5 groups (n = 10) according to the irrigation regimens used: conventional syringe irrigation (CI), Self-Adjusting File (SAF; ReDent-Nova, Ra'anana, Israel), EndoVac (Discus Dental, Culver City, CA), EndoActivator (Dentsply, Tulsa, OK), and passive ultrasonic irrigation (PUI). In 3 teeth, mTAP was not removed (positive controls), and another 3 teeth were not filled with mTAP (negative controls). The roots were sectioned, and the amount of remaining medicament at each root half (n = 20) was evaluated at 30× magnification using a 4-grade scoring system. Data were evaluated using the Kruskal-Wallis and Mann-Whitney U tests. ResultsThere were statistically significant differences among all experimental groups; of which, the CI group was the significantly least efficient in removing mTAP from the root canal (P < .05). At the apical and middle third, the PUI, SAF, EndoVac, and EndoActivator groups removed significantly more mTAP medicament than the CI group (P < .05); however, there were no significant differences between these groups (P > .05). The SAF and PUI showed significantly better performances in removing mTAP from the coronal third (P < .05). ConclusionsThe use of irrigation activation regimens significantly improves the removal of mTAP from root canals when compared with CI.

A case report on fluorosed teeth whitening without microabrasion - Is it possible?

Whitening of fluorosis stains ranging from yellow to dark brown presents a great challenge to the dentists. The aim of this study was to report the clinical case of a 32-year-old female patient with moderate fluorosis, who was treated using the combination of light-assisted in-office and at-home whitening system. The in-office whitening was performed using 25% hydrogen peroxide (Zoom DayWhite, Discus Dental, Stamford, USA) for four 15-min sessions with supplemental light (Philips Zoom, Stamford, USA) immediately followed by home whitening with a take-home custom tray using 22% carbamide peroxide (Zoom NiteWhite, Discus Dental, Stamford, USA) worn for 6 h a day for 1 week. Color measurements using a dental spectrophotometer (Spectroshade, MHT Optic Research AG, Niederhasli, Switzerland) after the first week showed that the suggested combination technique provided a fast whitening result with a high degree of patient satisfaction. The in-office whitening with light exhibited to be an efficient method for removing yellow and brown fluorosis stains, while the at-home whitening was useful for obtaining a uniform tooth shade. At the 6-month and 1-year recall, the teeth shade and appearance were evaluated. The results of this case report clearly show an effective esthetic result in the long term; however, the question of whether appropriate color stability would be provided by the technique still remains to be answered.

Efficacy of 3 Different Irrigation Systems on Removal of Calcium Hydroxide from the Root Canal: A Scanning Electron Microscopic Study

IntroductionThe purpose of this study was to evaluate the effectiveness of different irrigation systems on removing calcium hydroxide (Ca[OH]2) from the root canal by using a scanning electron microscope. MethodsForty extracted single-rooted teeth were divided randomly into 4 groups. Canal instrumentation was done, and the teeth were filled with Ca(OH)2 paste. One week later, 4 techniques were used for Ca(OH)2 removal. In the first group, the canals were cleaned with a master apical file. The second, third, and fourth groups were irrigated using the EndoVac (Discus Dental, Culver City, CA), EndoActivator (Dentsply Tulsa Dental Specialties, Tulsa, OK), and ProUltra (Dentsply Tulsa, Tulsa, OK) systems, respectively. All the groups were irrigated with 3 mL (18%) EDTA and 3 mL (1%) NaOCl for 1 minute. The canal walls were viewed, and the remaining amount of Ca(OH)2 was evaluated using a scanning electron microscope. A scoring system was used to assess the amount of residue Ca(OH)2 on each third of the canal. The obtained data for comparisons between the conventional irrigation needle and each device were statistically analyzed using the Mann-Whitney U test. ResultsTo compare the 4 devices, the results were statistically analyzed using the analysis of variance test. ConclusionsNone of the investigated techniques removed the Ca(OH)2 dressing completely. However, the EndoActivator System showed better results in removing Ca(OH)2 in each third of the root canals in comparison with the other techniques.

Efficacy of three different irrigation techniques in the removal of smear layer and organic debris from root canal wall: a scanning electron microscope study

AimAim of this study was to compare the removal of smear layer and organic debris within the tooth canal among conventional needle irrigation, EndoVac and Endoactivator. MethodologyEighty single-rooted extracted human teeth were prepared with rotary NiTi instrumentation and randomly separated into 4 groups. Twenty teeth were used as positive control (Group 1), irrigated with only saline. Teeth assigned to Group 2 (n=20) received irrigation with a conventional syringe and a 30-gauge needle (NaviTip, Ultradent, South Jordan, UT); samples in Group 3 (n=20) were rinsed with an irrigation device based on apical negative pressure (EndoVac, Discus Dental, Culver City, CA) and teeth in Group 4 (n=20) were treated with a sonic irrigation system (EndoActivator, Dentsply Tulsa Dental, Tulsa, OK, USA). The amount of residual smear layer and debris was evaluated under a scanning electron microscope, and a semi-quantitative score was assigned to each root at the coronal, middle and apical thirds; the chi-square test was used to compare the results of the S.E.M. analysis. ResultsEndoActivator performed the best cleansing for both smear layer and organic debris in all root canal thirds, followed by EndoVac and conventional irrigation (p>0.001). EndoVac and conventional irrigation showed better cleaning in the coronal area, whereas EndoActivator performed an homogeneous cleansing at all levels. ConclusionsThe EndoVac system and the EndoActivator system demonstrated significantly more efficacy in cleansing root canal walls than conventional needle irrigation.

Comparative Evaluation of Canal Isthmus Debridement Efficacy of Modified EndoVac Technique with Different Irrigation Systems

IntroductionThe purpose of this study was to evaluate the canal isthmus debridement efficacy of a new modified EndoVac (Discus Dental, Culver City, CA) irrigation protocol in comparison with EndoVac, passive ultrasonic irrigation (PUI), and conventional needle irrigation in mesial roots of mandibular molars. MethodsThe mesial roots of 64 extracted mandibular molars mounted in resin using Kuttler's endodontic cube, sectioned at 2 and 4 mm from the working length, were randomly divided into 4 groups (n = 16): group 1: Max-I-Probe (Dentsply Tulsa Dental, York, PA), group 2: EndoVac (EVI), group 3: modified EndoVac, and group 4: PUI. The specimens were reassembled and instrumented. A standard irrigation protocol was used during cleaning and shaping and final irrigation with the 4 irrigation/agitation techniques. Images of the isthmus region were taken before and after cleaning and shaping and after final irrigation. The percentage reduction of debris in the isthmus region was calculated by using the software program Image J (v1.43; National Institutes of Health, Bethesda, MD). Intergroup analysis was performed using the Kruskal Wallis and Mann-Whitney U tests. Intragroup analysis was performed using Friedman and Wilcoxon signed rank tests. The level of significance was set at P < .05. ResultsIntragroup analysis revealed a statistically significant difference in the percentage reduction of debris after cleaning and shaping and after final irrigation protocol in all the groups (P < .001). The final irrigation protocol produced significantly cleaner canal isthmuses in all the groups (P < .001). On intergroup analysis, the modified EVI group performed significantly better than the other groups. The EVI and PUI groups performed better than the Max-I-Probe group. There was no statistical significance between the EVI and PUI groups. ConclusionsCanal isthmuses were significantly cleaner with the modified EndoVac irrigation technique when compared with the cleanliness seen with the other irrigation systems.

Effect of 38% carbamide peroxide on the microleakage of silorane-based versus methacrylate-based composite restorations.

ObjectivesThis study aimed to assess the effect of 38% carbamide peroxide on the microleakage of class V cavities restored with either a silorane-based composite or two methacrylate-based composites.Materials and MethodsA total of 96 class V cavities were prepared on the buccal surface of extracted human teeth with both enamel and dentin margins and were randomly assigned into three groups of Filtek P90 (3M-ESPE) + P90 system adhesive (3M-ESPE)(group A), Filtek Z250 (3M-ESPE) + Adper Prompt L-Pop (3M-ESPE)(group B) and Filtek Z350XT (3M-ESPE) + Adper Prompt L-Pop (group C). Half of the teeth were randomly underwent bleaching (38% carbamide peroxide, Day White, Discus Dental, applying for 15 min, twice a day for 14 day) while the remaining half (control) were not bleached. Dye penetration was measured following immersion in basic fuchsine. Data were statistically analyzed using Kruskal-Wallis and Mann-Whitney U tests at a level of 0.05.ResultsNo significant differences were found between composites in the control groups in enamel (p = 0.171) or dentin (p = 0.094) margins. After bleaching, microleakage of Z250 (in enamel [p = 0.867] or dentin [p = 0.590] margins) and Z350 (in enamel [p = 0.445] or dentin [p = 0.591] margins) did not change significantly, but the microleakage of P90 significantly increased in both enamel (p = 0.042) and dentin (p = 0.002) margins.ConclusionsNo significant differences were noted between the bleached and control subgroups of two methacrylate-based composites in enamel or dentin margins. Microleakage of silorane-based composite significantly increased after bleaching.

Influence of whitening gel on pulp chamber temperature rise by in-office bleaching technique

INTRODUCTION: Dental bleaching is a conservative method for the aesthetic restoration of stained teeth. However, whitening treatments are likely to cause adverse effects when not well planned and executed. OBJECTIVE: This study evaluated the influence of whitening gel on temperature rise in the pulp chamber, using the in-office photoactivated dental bleaching technique. MATERIAL AND METHOD: The root portion of an upper central human incisor was sectioned 3mm below the cemento-enamel junction. The root canal was enlarged to permit the insertion of the K-type thermocouple sensor (MT-401) into the pulp chamber, which was filled with thermal paste to facilitate the transfer of heat during bleaching. Three photosensitive whitening agents (35% hydrogen peroxide) were used: Whiteness HP (FGM), Whiteness HP Maxx (FGM) and Lase Peroxide Sensy (DMC). An LED photocuring light (Flash Lite - Discus Dental) was used to activate the whitening gels. Six bleaching cycles were performed on each group tested. The results were submitted to one-way ANOVA and LSD t-test (α&lt;0.05). RESULT: The lowest mean temperature variation (ºC) was detected for Lase Peroxide Sensy (0.20), while the highest was recorded for Whiteness HP (1.50). CONCLUSION: The Whiteness HP and Whiteness HP Maxx whitening gels significantly affected the temperature rise in the pulp chamber during bleaching, and this variation was dependent on the type of whitening gel used.

Effect of Different Final Irrigation Methods on the Removal of Calcium Hydroxide from an Artificial Standardized Groove in the Apical Third of Root Canals

IntroductionThe aim of this study was to compare the efficacy of conventional syringe, ultrasonic, EndoVac (Discus Dental, Culver City, CA), and Self-Adjusting File (SAF) (Re-Dent-Nova, Ra'nana, Israel) irrigation systems in removing calcium hydroxide (Ca[OH]2) from simulated root canal irregularities. MethodsThe root canals of 88 extracted single-rooted teeth were prepared using ProTaper rotary instruments (Dentsply Maillefer, Ballagiues, Switzerland) up to size F4. The roots were split longitudinally, and a standardized groove was prepared in the apical part of 1 segment. The root halves were reassembled, and Ca(OH)2 medicament was placed into the root canals using a Lentulo spiral. The roots were randomly divided into 4 experimental groups and 2 control groups according to the different irrigation systems used: conventional syringe irrigation, continuous passive ultrasonic irrigation (PUI), EndoVac irrigation, and SAF irrigation. Each group was then divided into 2 subgroups (n = 10) according to the irrigation protocol: subgroup 1: 10 mL 2.5% NaOCl and subgroup 2: 10 mL 17% EDTA + 10 mL 2.5% NaOCl. The amount of remaining medicament was evaluated under a stereomicroscope at 30× magnification using a 4-grade scoring system. The influences of the different Ca(OH)2 medicament removal methods and irrigation protocols were statistically evaluated using 2-way analysis of variance and Tukey post hoc tests. ResultsIn the NaOCl-irrigated groups, PUI removed significantly more Ca(OH)2 medicament than the other techniques (P < .05). There was no significant difference among the other groups (P > .05). In the EDTA/NaOCl-irrigated groups, the SAF and PUI removed significantly more Ca(OH)2 than the other techniques (P < .05). ConclusionsThe use of the SAF system with the combination of EDTA and NaOCl enhanced Ca(OH)2 removal when compared with the use of only NaOCl irrigation with the SAF. Continuous PUI and SAF were more effective than EndoVac, and conventional syringe irrigation in the removal of the Ca(OH)2 medicament from an artificial standardized groove in the apical part of the root canal.

Smear Layer Removal and Canal Cleanliness Using Different Irrigation Systems (EndoActivator, EndoVac, and Passive Ultrasonic Irrigation): Field Emission Scanning Electron Microscopic Evaluation in an In Vitro Study

IntroductionThe purpose of this study was to evaluate the effectiveness of different irrigating methods in removing the smear layer at 1, 3, 5, and 8 mm from the apex of endodontic canals. MethodsSixty-five extracted single-rooted human mandibular premolars were decoronated to a standardized length of 16 mm. Specimens were shaped to ProTaper F4 (Dentsply Maillefer, Ballaigues, Switzerland) and irrigated with 5.25% NaOCl at 37°C. Teeth were divided into 5 groups (2 control groups [n = 10] and 3 test groups [n = 15]) according to the final irrigant activation/delivering technique (ie, sonic irrigation, passive ultrasonic irrigation [PUI], or apical negative pressure). Root canals were then split longitudinally and observed by field emission scanning electron microscopy. The presence of debris and a smear layer at 1, 3, 5, and 8 mm from the apex was evaluated. Scores were analyzed by Kruskal-Wallis and Mann-Whitney U tests. ResultsThe EndoActivator System (Dentsply Tulsa Dental Specialties, Tulsa, OK) was significantly more efficient than PUI and the control groups in removing the smear layer at 3, 5, and 8 mm from the apex. The EndoVac System (Discus Dental, Culver City, CA) removed statistically significantly more smear layer than all groups at 1, 3, 5, and 8 mm from the apex. At 5 and 8 mm from the apex, PUI and the EndoVac did not differ statistically significantly, but both performed statistically better than the control groups. ConclusionsIn our study, none of the activation/delivery systems completely removed the smear layer from the endodontic dentine walls; nevertheless, the EndoActivator and EndoVac showed the best results at 3, 5, and 8 mm (EndoActivator) and 1, 3, 5, and 8 mm (EndoVac) from the apex.

Evaluation of metallic brackets adhesion after the use of bleaching gels with and without amorphous calcium phosphate (ACP): in vitro study

To evaluate in vitro the effects of tooth whitening using gel with Amorphous Calcium Phosphate (ACP) on the bond strength of metal brackets. Thirty-six bovine incisors were sectioned at the crown-root interface, and the crowns were then placed in PVC cylinders. The specimens were divided into 3 groups (n = 12) according to whitening treatment and type of gel used, as follows: G1 (control) - no whitening; G2 - whitening with gel not containing ACP (Whiteness Perfect - FGM), G3 - whitening with gel containing ACP (Nite White ACP - Discus Dental). Groups G2 and G3 were subjected to 14 cycles of whitening followed by an interval of 15 days before the bonding of metal brackets. Shear bond strength testing was performed on a Kratos universal test machine at a speed of 0.5 mm/min. After the mechanical test, the specimens were assessed to determine the adhesive remnant index (ARI). The results were subjected to ANOVA, Tukey's test and Kruskal-Wallis test (5%). Significant differences were noted between the groups. Control group (G1 - 11.10 MPa) showed a statistically higher shear bond strength than the groups that underwent whitening (G2 - 5.40 Mpa, G3 - 3.73 MPa), which did not differ from each other. There were no significant differences between the groups in terms of ARI. Tooth whitening reduces the bond strength of metal brackets, whereas the presence of ACP in the whitening gel has no bearing on the results.

Efficacy and Safety of Various Active Irrigation Devices When Used with Either Positive or Negative Pressure: An In Vitro Study

IntroductionThe purpose of this in vitro study was to evaluate and compare the efficacy and safety of different devices available for canal cleansing. MethodsThe following systems were tested: passive ultrasonic irrigation, EndoVac (Discus Dental, Culver City, CA), and the irrigation ultrasonic needle (ProUltra PiezoFlow Irrigation Ultrasonic Needle; Dentsply Tulsa Dental Specialties, Tulsa, OK) used in both the injection mode (IUNI) and the aspiration mode (IUNA). In the control group, traditional irrigation with a syringe and side-vented needle was used. A resin model was used with 4 lateral canals (respectively at 2, 5, 8, and 11 mm from the apical foramen) filled with bovine pulp stained with fuchsin. The model also included a 2-mm chamber in communication with the apex, again filled with bovine pulp, which enabled the measurement of the extrusion of NaOCl beyond the apex. ResultsWith regard to efficacy, the most effective systems were found to be those using the ultrasonic needle, either in aspiration or injection modes; EndoVac was the least effective. Conversely, IUNI was found to bring the highest risk with regard to the extrusion of sodium hypochlorite beyond the apex. EndoVac was the safest but only by a slight margin compared with IUNA and passive ultrasonic irrigation. ConclusionsBased on this study, the system that best reconciles efficacy and safety appears to be IUNA.

Success Rate of Single- versus Two-visit Root Canal Treatment of Teeth with Apical Periodontitis: A Randomized Controlled Trial

IntroductionThe aim of this study was to evaluate the outcome of single- versus 2-visit root canal treatment of teeth with apical periodontitis after a 2-year follow-up period. MethodsThree hundred maxillary and mandibular nonvital teeth with apical periodontitis were treated in either a single visit or 2 visits. The main inclusion criteria were radiographic evidence of apical periodontitis (minimum size ≥2.0 × 2.0 mm) and a diagnosis of pulpal necrosis confirmed by a negative response to hot and cold tests. Radiographically, all teeth showed small and irregular periapical radiolucencies before treatment. The canals were enlarged with LightSpeedLSX (Discus Dental, Culver City, CA) root canal instruments to a final apical preparation size #60 for anterior and premolar teeth and size #45 to #55 for molars. The EndoVac negative-pressure irrigation system (Discus Dental) was used for disinfecting irrigation, and all canals were filled by lateral compaction of gutta-percha and Sealapex sealer (SybronEndo, Orange, CA). The healing results were clinically and radiographically evaluated 2 years postoperatively. ResultsOf the 300 teeth treated, 18 were lost to follow-up, 9 in the 2-visit group and 9 in the 1-visit group. Of the 282 teeth studied, the randomization procedure had allocated 146 teeth to 1-visit treatment and 136 teeth to 2-visit treatment. Teeth with symptoms of persisting periapical inflammation were scored as not healed. Teeth with a reduced periapical rarefaction were judged as uncertain. Teeth with complete restitution of the periodontal contours were judged as healed. In the 1-visit group, 141 of 146 teeth (96.57%) were classified as healed as compared with 121 (88.97%) of 136 teeth in the 2-visit group. Eleven cases were classified as uncertain in the 2-visit group (8.08%) compared with 4 (2.73%) in the 1-visit group. Two of 10 teeth in the 2-visit group presented with pain before the 2-year follow-up and were classified as not healed. The hypothesis tests were conducted at the 0.05 level of significance. Statistical analysis of the healing results did not show any significant difference between the groups (P = .05). ConclusionsSeveral factors play an important role in the decision-making process of 1- versus 2-visit endodontics. Among these are objective factors like preoperative diagnosis, the ability to obtain infection control, root canal anatomy, procedural complications, and subjective factors like patients' signs and symptoms. This study provided evidence that with a treatment protocol with instrumentation to predefined larger apical instrumentation sizes and irrigation with a negative apical pressure system can lead to healing in cases of apical periodontitis, which is a significant finding compared with more dated studies that showed average healing of apical periodontitis cases. With the given sample size, there was no statistically significant difference between the 2 treatment modalities.

Clinical assessment of whitening efficacy and safety of in-office tooth whitening system containing 15% hydrogen peroxide with or without light activation

Objectives: This clinical study evaluated the effect of light activation on the whitening efficacy and safety of in-office bleaching system containing 15% hydrogen peroxide gel. Materials and Methods: Thirty-three volunteers were randomly treated with (n = 17, experimental group) or without light activation (n = 16, control group), using Zoom2 white gel (15% , Discus Dental) for a total treatment time of 45 min. Visual and instrumental color measurements were obtained using Vitapan Classical shade guide and Shadepilot (DeguDent) at screening test, after bleaching, and 1 month and 3 month after bleaching. Data were analyzed using t-test, repeated measure ANOVA, and chi-squared test. Results: Zoom2 white gel produced significant shade changes in both experimental and control group when pre-treatment shade was compared with that after bleaching. However, shade difference between two groups was not statistically significant (p > 0.05). Tooth shade relapse was not detected at 3 months after bleaching. The incidence of transient tooth sensitivity was 39.4%, with being no differences between two groups. Conclusions: The application of light activation with Zoom2 white gel system neither achieved additional whitening effects nor showed more detrimental influences.

Postoperative Pain after the Application of Two Different Irrigation Devices in a Prospective Randomized Clinical Trial

Introduction The extrusion of irrigation solutions beyond the apical constriction may result in postoperative pain. Sodium hypochlorite can cause severe tissue irritation and necrosis outside the root canal system if extruded into the periodontal ligament (PDL) space. Different delivery techniques were discussed to reduce this potential risk. The aim of this study was to compare the postoperative level of pain after root canal therapy using either endodontic needle irrigation or a negative apical pressure device. Material and Methods In a prospective randomized clinical trial, 110 asymptomatic single-rooted anterior and premolar teeth were treated endodontically with two different irrigation techniques. The teeth were randomly assigned to two groups. In the MP group ( n = 55), procedures were performed using an endodontic irrigating syringe (Max-i-Probe; Dentsply Rinn, Elgin, IL). The EV group ( n = 55) used an irrigation device based on negative apical pressure (EndoVac; Discus Dental, Culver City, CA). Postoperatively, the patients were prescribed ibuprofen 200 mg to take every 8 hours if required. Pain levels were assessed by an analog scale questionnaire after 4, 24, and 48 hours. The amount of ibuprofen taken was recorded at the same time intervals. Results During the 0- to 4-, 4- to 24-, and 24- to 48-hour intervals after treatment, the pain experience with the negative apical pressure device was significantly lower than when using the needle irrigation (p < 0.0001 [4, 24, 48 hours]). Between 0 and 4 and 4 and 24 hours, the intake of analgesics was significantly lower in the group treated by the negative apical pressure device (p < 0.0001 [0-4 hours], p = 0.001 [4-24 hours]). The difference for the 24- to 48-hour period was not statistically different (p = 0.08). The Pearson correlation coefficient revealed a strongly positive and significant relationship for the MP group ( r = 0.851, p < 0.001) and the EV group ( r = 0.596, p < 0.0001) between pain intensity and the amount of analgesics. Conclusion The outcome of this investigation indicates that the use of a negative apical pressure irrigation device can result in a significant reduction of postoperative pain levels in comparison to conventional needle irrigation.