Association between rheumatoid arthritis and pulpal-periapical pathology: a systematic review.

OBJECTIVES: Rheumatoid arthritis (RA) is a debilitating disease where numerous pro-inflammatory cytokines have a proven role in its pathology. These cytokines are also involved in the pathogenesis of apical periodontitis (AP) where they have a pro-inflammatory role and induce bone resorption. Patients with RA may therefore be more prone to develop pulpal-periapical pathology (PPP). This study systematically reviewed the existing literature evaluating the association between RA and PPP. MATERIALS AND METHODS: Studies including human participants with both RA and PPP were included. The search was performed in PubMed, Web of Science, and The Cochrane Library databases using keywords and Medical Subject Headings (MeSH) search terms. The risk of bias was assessed using Newcastle-Ottawa Quality Assessment Scale. The following parameters were extracted and analyzed by the reviewers; author, journal, year, design of the study, diagnostic criteria for periapical pathology, the association between rheumatoid arthritis and periapical pathology, and the evidence level. RESULTS: The search identified 142 records. Inclusion criteria were as follows; studies in the English language, including human participants only, including patients with RA and PPP, cohort studies, cross-sectional studies, clinical trials, and case-control studies. According to the inclusion criteria, 5 studies were included in this systematic review. Three of the five studies reported significant association between RA and PPP. CONCLUSIONS: Existing evidence suggests there may be an association between RA and PPP. CLINICAL RELEVANCE: Clinicians should be aware that RA patients can be more prone to develop PPP which may result in a reduced quality of life.

Effect of calcium hydroxide alone or in combination with ibuprofen and ciprofloxacin on postoperative pain and periapical prostaglandin E2 level: A randomized clinical study.

AIM: The aim of the present study was to compare pure Ca(OH)2, Ca(OH)2 + ibuprofen and Ca(OH)2 + ciprofloxacin in terms of postoperative pain and prostaglandin E2 (PGE2) level in previously treated teeth with periapical lesions. MATERIALS AND METHODS: Sixty-six patients were randomly assigned into 3 groups according to the intracanal medication (Ca(OH)2, Ca(OH)2 + ibuprofen and Ca(OH)2 + ciprofloxacin). After removing gutta-percha from the root canals, the PGE2 sample collection was obtained by introducing three sterile paper points into the root canals through the root apex (2 mm). Selected intracanal medicament was placed into the root canal and the participants were told to record postoperative pain levels at 24, 48, and 72 h and on 1 week after treatment using visual analog scale (VAS). At the second appointment, the medicaments were removed and second sampling was performed using the same method. The PGE2 levels measured by enzyme-linked immunosorbent assay kits, and the data were statistically analyzed. RESULTS: All the tested Ca(OH)2 pastes were found to be significantly effective in lowering the preoperative PGE2 levels. However, intergroup analyses revealed that the Ca(OH)2 + ciprofloxacin group had the highest effectiveness in lowering PGE2 with a significant difference when compared with the pure Ca(OH)2 group. There was no statistically significant difference among the groups in terms of pre- and post-operative pain levels. CONCLUSION: The Ca(OH)2 + ciprofloxacin medication is more effective than the pure Ca(OH)2 medication in lowering periapical PGE2 level. However, addition of ibuprofen or ciprofloxacin to the Ca(OH)2 paste does not provide extra benefit in terms of post-operative pain relief.

Effect of intracanal medicaments on matrix metalloproteinase-9 and vasoactive intestinal peptide secretion in periapical lesions of re-treated canals: a randomized controlled clinical study.

OBJECTIVE: The aim of this study was to evaluate the effect of calcium hydroxide (Ca[OH]2) and chlorhexidine (CHX) gel on matrix metalloproteinase-9 (MMP-9) and vasoactive intestinal peptide (VIP) secretion in periapical lesions. MATERIALS AND METHODS: A total of 60 patients were randomly divided into two groups that were to receive different medications. Pre-and post-treatment samples were collected from the interstitial fluid of periapical lesions using sterile paper points. VIP and MMP-9 levels were measured by enzyme-linked immunosorbent assay kits, and the data were statistically analyzed. RESULTS: Gender and smoking habits had no effect on the pre- and post-treatment VIP and MMPs levels. Intragroup analyses revealed that in the Ca(OH)2 group, the post-treatment VIP level was found to be significantly higher than the pre-treatment VIP level. In the CHX group, the post-treatment MMP-9 level was significantly higher than the pre-treatment MMP-9 level. CONCLUSION: According to the results of the present study, the type of the medication affected the amount of periapical VIP and MMP-9 secretion. CLINICAL RELEVANCE: VIP is a neuropeptide that promotes new bone formation. Thus, intracanal Ca(OH)2 medication may accelerate the repair process of bone tissue.

The effect of various occlusal reduction levels on postoperative pain in teeth with symptomatic apical periodontitis using computerized analysis: a prospective, randomized, double-blind study.

OBJECTIVE: The objective of this study was to evaluate the effect of various occlusal reduction levels on the postoperative pain in teeth diagnosed as symptomatic apical periodontitis by using a computerized analysis system. MATERIALS AND METHODS: Thirty-nine molar teeth with symptomatic apical periodontitis were included. After the root canal preparation and filling was performed, the subjects were divided into three groups according to the level of occlusal reduction determined by using T-Scan (T-Scan III for Windows, Tekscan Inc., South Boston, MA) as follows: (1) no reduction (control), (2) semi-reduction, and (3) full-reduction groups. Preoperative and postoperative pain levels using visual analogue scale, percussion pain, and analgesic intake were recorded for each subject. The data were evaluated statistically using two-way analysis of variance and Holm-Sidak post hoc tests at a 95 % confidence level (P = 0.05). RESULTS: There was no significant difference between the groups in terms of occlusal reduction (P > 0.005). CONCLUSION: Within the limitation of the present study, there were no significant differences among the no reduction, semi-reduction, and full-reduction groups at 1, 3, 5, and 7 days in terms of postoperative pain levels. CLINICAL RELEVANCE: Occlusal reduction, determined using a computerized analysis system, did not influence the postoperative pain in teeth diagnosed as symptomatic apical periodontitis.

The Effect of Diode Laser With Different Parameters on Root Fracture During Irrigation Procedure.

The aim of this study is to compare the effect of a single diode laser application and agitation of EDTA with diode laser with different parameters at different time intervals on root fracture. Ninety mandibular incisors were instrumented except the negative control group. The specimens were divided randomly into 10 groups according to final irrigation procedure: (G1) non-instrumented; (G2) distilled water; (G3) 15% EDTA; (G4) ultrasonically agitated EDTA; (G5) single 1.5W/100 Hz Diode laser; (G6) single 3W/100 Hz Diode laser; (G7) 1.5W/100 Hz Diode laser agitation of EDTA for 20 s; (G8) 1.5W/100 Hz Diode laser agitation of EDTA for 40 s; (G9) 3W/100 Hz Diode laser agitation of EDTA for 20 s; and (G10) 3W/100 Hz Diode laser agitation of EDTA for 40 s. The specimens were filled, mounted in acrylic resin, and compression strength test was performed on each specimen. Statistical analysis was carried out using one way ANOVA and Tukey's post hoc tests (P = 0.05). The statistical analysis revealed that there were statistically significant differences among the groups (P < 0.05). Laser-agitated irrigation with a 3W/100 Hz Diode laser for both 20 s and 40 s decreased the fracture resistance of teeth.

Influence of Instruments Used in Root Canal Preparation on Amount of Apically Extruded Debris.

The aim of the present study was to compare the effects of ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne instruments on the amount of apically extruded debris. Eighty mandibular premolar teeth with straight root canals were selected and assigned to four groups (n = 20). The root canals were instrumented using ProTaper Gold, WaveOne Gold, ProTaper Universal, and WaveOne systems. Eppendorf tubes containing apically extruded debris were weighed three times, and mean values were calculated. The net mass of the extruded debris was calculated by subtracting the initial mass from the final mass. The groups were compared using one-way analysis of variance and Tukey's post hoc tests at a significance level of P < 0.05. The PTG group extruded less debris than the PTU group, and the WOG group extruded less debris than the WO group (P < 0.05). All the instrumentation systems tested in the present study were associated with apical extrusion of debris.

Influence of ultrasonic and sonic activation of epoxy-amine resin-based sealer on penetration of sealer into lateral canals.

OBJECTIVES: The aim of this study was to evaluate the efficacy of sonic and ultrasonic activation of epoxy-amine resin-based root canal sealer (2Seal; VDW GmbH, München, Germany) on penetration of the sealer into lateral canals compared to non-activated filling. MATERIALS AND METHODS: Thirty-six single-rooted human anterior teeth were decoronated and prepared, using the ProTaper rotary system (Dentsply Maillefer, Ballaigues, Switzerland) to F4. After the completion of the clearing procedures, lateral canals were created at 2, 4, and 6 mm from the working length. The specimens were randomly divided into a control group (non-activated sealer application) and two experimental groups that received a sealer application with either sonic or ultrasonic activation. The root canals were filled using cold lateral compaction and images were obtained from each lateral canals at 40× magnification using a stereomicroscope. The sealer penetration was evaluated using a four-grade scoring system. The data were evaluated statistically using the Kruskal-Wallis and Mann-Whitney U tests with a 95 % confidence level (P = 0.05). RESULTS: The ultrasonic activation resulted in a better sealer penetration compared with the non-activated and sonically activated groups (P < 0.001). Sonic activation also resulted in better sealer penetration compared to the non-activated group (P < 0.001). CONCLUSIONS: The use of the ultrasonic activation of an epoxy-amine resin-based sealer promoted greater sealer penetration into the lateral canals. Sonic activation was not effective as ultrasonic activation, but was more effective than the non-activated group. CLINICAL RELEVANCE: The ultrasonic activation of an epoxy-amine resin-based sealer could be beneficial in filling procedures.

Effect of agitation of EDTA with 808-nm diode laser on dentin microhardness.

The aim of this study is to analyze the effect of agitation of ethylenediaminetetraacetic acid (EDTA) with diode laser at different agitation times on root dentin microhardness. Eighty-four specimens were divided randomly into seven groups, as follows: (1) distilled water, (2) 17% EDTA, (3) EDTA with 60 s ultrasonic agitation, (4) EDTA with 10 s laser agitation, (5) EDTA with 20 s laser agitation, (6) EDTA with 30 s laser agitation, and (7) EDTA with 40 s laser agitation. All of the specimens were irrigated with 5% NaOCl and distilled water except the distilled water group. Microhardness values were calculated before and after the procedures. Statistical analyses were performed using one-way ANOVA and Tukey post hoc tests. Statistically significant differences were determined between the distilled water and other groups. Also, statistically significant differences were observed between EDTA with 40 s laser agitation and EDTA, and EDTA with 10 and 20 s laser agitations. Ultrasonic agitation of EDTA affected microhardness of root dentin similar to EDTA (p > .05). All applications decreased the microhardness of root dentin when compared with distilled water. Agitation of EDTA with diode laser for 40 s caused more reduction in microhardness of root dentin when compared with EDTA.

Efficacy of different treatments of root canal walls on the pull-out bond strength of the fiber posts.

The aim of this study was to evaluate the efficacy of different irrigation protocols, including laser, on the retention of the fiber-reinforced composite posts to root canal dentinal walls using pull-out tests. Root canals of 60 single-rooted human teeth were filled and post spaces were prepared. Finally, specimens were divided randomly into five groups, each consisting of 12 specimens as follows: 5% NaOCl (control group), 17% EDTA, ultrasonic with 17% EDTA, single 1.5-W Er:YAG laser application, and the combined use of Er:YAG laser and 17% EDTA. After the root canal procedures, fiber posts were cemented to the root canal. Pull-out tests were performed using a universal testing machine at a crosshead speed of 2 mm/min. The data were analyzed using a one-way ANOVA and Bonferroni post hoc test (p = 0.05). Irradiation by the Er:YAG laser with/without EDTA positively affected the pull-out bond strength (p < 0.001). The pull-out strength was significantly higher in the ultrasonic group than that of the single irrigation with NaOCl or EDTA (p < 0.001). Er:YAG laser irradiation with/without EDTA enhanced the bond strength of fiber posts to root canal dentin walls. Additionally, ultrasonic-EDTA combination increased the bond strength.

Effects of post surface treatments including Er:YAG laser with different parameters on the pull-out bond strength of the fiber posts.

This study aims to evaluate the effects of Er:YAG laser irradiation under different power settings on the pull-out bond strengths of fiber-reinforced composite posts. The crowns of single-rooted 60 teeth were removed by separation and the root canals were cleaned and shaped. Root canals were filled and post spaces were prepared. Sixty fiber posts were divided into five groups according to surface treatment methods as follows: an untreated control group, a sandblasting-coated group, and three groups undergoing surface preparation with Er:YAG laser under three different power settings (150, 300, and 450 mJ at 10 Hz for 60 s at 100-µs pulse duration). After root canal procedures, fiber posts were cemented to the root canal. After all of the specimens were set, pull-out tests were performed using a universal testing machine at a crosshead speed of 2 mm/min. The data were analyzed using one-way ANOVA and Tukey post-hoc test (p < 0.05). The pull-out strength values ranged between 5.26 and 6.76 Mpa. The lowest values were observed in the groups without surface treatment. Surface treatment applied by 4.5-W Er:YAG laser increased the pull-out bond strength compared to the control group (p < 0.05). 4.5-W Er:YAG laser irradiation increased the pull-out bond strength of fiber posts to resin cement.

Association Between Single-nucleotide Polymorphisms in Candidate Genes and Success of Pulpal Anesthesia after Inferior Alveolar Nerve Block.

INTRODUCTION: The present study aimed to investigate the possible association between the single-nucleotide polymorphisms (SNPs) in the SCN9A, SCN10A, SCN11A, OPRM1, and COMT genes and the success rate of pulpal anesthesia after inferior alveolar nerve block (IANB). METHODS: A total of 70 patients (45 females and 25 males) presenting mandibular molar teeth with symptomatic irreversible pulpitis were included. Saliva samples were collected from the participants before the application of IANB. A standard IANB was performed with 1.8 mL 4% articaine with 1:100,000 epinephrine. Endodontic treatment was initiated 15 minutes after injection, and the patients were asked to report their pain level during the procedure on a 170-mm Heft-Parker visual analog scale. If the patient recorded a pain level of lower than 54 on the visual analog scale (no pain or mild pain), the anesthesia was considered successful. The DNA isolation and genotyping were performed, and the association between rs4286289, rs6746030, rs6795970, rs6801957, rs11709492, rs1799971, rs1799973, rs4680, rs6269, rs4633, and rs740603 SNPs and the success rate of anesthesia was investigated. RESULTS: The anesthesia success rate was significantly lower for the GG genotypes (45%) than the GA and AA genotypes (90%) for rs6795970 in the SCN10A gene. Additionally, the A allele for rs6795970 and the T allele for rs6801957 in the SCN10A gene were significantly associated with higher anesthesia success rates. CONCLUSIONS: SNPs in the SCN10A gene affect the success rate of pulpal anesthesia after IANB.

Postoperative Pain After the use of Sodium Hypochlorite gel and Solution Forms: A Randomized Clinical Study.

OBJECTIVE: The present study aimed to compare the effect of sodium hypochlorite (NaOCl) gel and solution forms on postoperative pain level. METHODS: Fifty-two patients were divided into two groups according to the root canal irrigation solution. In the NaOCl solution group, the root canals were irrigated with 2 mL of 5.25% NaOCl between each pecking motion. In the NaOCl gel group, 5.25% NaOCl gel was used according to the manufacturer's instructions. The root canal treatments were completed and the participants were given instructions to record postoperative pain levels on 24, 48, and 72 hours and 1 week after treatment using VAS. RESULTS: Intergroup analyses revealed that the NaOCl gel group resulted in significantly less postoperative pain than the NaOCl solution group on day 1. CONCLUSION: It can be concluded that using NaOCl gel during root canal preparation results in less postoperative on day 1 when compared with the NaOCl solution.

Effect of final irrigation with sodium hypochlorite at different temperatures on postoperative pain level and antibacterial activity: a randomized controlled clinical study.

OBJECTIVE: To evaluate the effect of final irrigation of root canals with NaOCl solution at different temperatures on postoperative pain level and antimicrobial activity. METHODOLOGY: 45 patients were randomly divided into three groups using a web program according to the irrigation selected: NaOCl 2ºC, NaOCl 25ºC and NaOCl 45ºC. First root canal samples were collected before treatment (S1). After chemo-mechanical preparation, final irrigation was performed with the selected irrigant (NaOCl 2ºC, NaOCl 25ºC and NaOCl 45ºC) and second samples were collected (S2). Samples were subjected to quantitative real-time polymerase chain reaction to evaluate the levels of total bacteria. The root canal treatments were completed and the participants were given instructions to record postoperative pain levels at 24, 48 and 72 hours, 5 days and 1 week after treatment using a visual analog scale (VAS). RESULTS: The reduction in the number of total bacterial cell equivalents from S1 to S2 was statistically significant in all groups (p<0.001). The NaOCl 2˚C group reported significantly less postoperative pain than the NaOCl 45˚C group (p<0.05). Postoperative analgesic intake was significantly higher in the NaOCl 45˚C group than in the NaOCl 2˚C group (p<0.05). CONCLUSION: We conclude that final irrigation with NaOCl at different temperatures results in similar antibacterial effectiveness. Final irrigation with cold NaOCl (2˚C) is better than NaOCl 45˚C when comparing postoperative pain levels.

Association between Rheumatoid Arthritis and Apical Periodontitis: A Cross-sectional Study.

Objective: The present cross-sectional study aimed to investigate possible association between Rheumatoid Arthritis (RA) and Apical Periodontitis (AP). Methods: In table one it is mentioned 48 patients diagnosed with RA were included in the experimental group. Another 48 healthy age- and gender-matched participants who reported no history of any systemic disease were selected to form the control group. All the patients were examined radiographically and clinically to diagnose the presence of AP. The following data was recorded for all patients; the number of teeth present, the number of teeth with AP, the number of patients with AP, the number of patients with root canal treated teeth (RCT) and the number of patients with RCT+AP. The chi-square test and logistic regression analysis were used to determine the possible association between RA and AP. Results: A total of 1026 teeth were examined in the RA group and 45 of them was diagnosed as AP. In the control group, 1025 teeth were examined and 21 teeth were diagnosed as AP. It was found that the prevalence of teeth with AP (4.3%) was significantly higher in the RA group than the control (2%) (odds ratio [OR]=2.193, P=0.003). Logistic regression analysis showed that RA is significantly associated with AP. Conclusion: It can be concluded that patients with RA can be more prone to develop AP.

Association of ankylosing spondylitis with radiographically and clinically diagnosed apical periodontitis: A cross-sectional study.

BACKGROUND: There are no studies evaluating the possible association between ankylosing spondylitis (AS) and apical periodontitis (AP). OBJECTIVES: The aim of the present cross-sectional study was to investigate the possible association between AS and AP. MATERIAL AND METHODS: Fifty patients diagnosed with AS, receiving treatment at the Rheumatology Clinic in Erzurum, Turkey, were included in the experimental group. Another 50 ageand gender-matched individuals without any history of systemic disease were included in the study as the control group. All patients were examined radiographically and clinically to diagnose the presence of AP. The following data was recorded for all patients: the smoking habit, the number of teeth present, the number of teeth with AP, the number of root canal-treated (RCT) teeth, and the number of RCT teeth with AP. RESULTS: There were 1,283 teeth in the AS group and 1,305 in the control group. There was a significant association between teeth with AP and AS, as the prevalence of teeth with AP was significantly lower in the control group (1.3%) than in the AS group (2.9%) (OR (odds ratio) = 2.250; p = 0.005). There was no statistically significant difference between the groups in terms of the number of RCT teeth and RCT teeth with AP (p > 0.05). CONCLUSIONS: Ankylosing spondylitis is significantly associated with an increased prevalence of AP. It can be concluded that patients with AS can be more prone to develop AP. However, AS does not reduce the success rate of endodontic treatment, because there was no significant difference between the AS and control groups in terms of RCT teeth with AP.

Micro-computed Tomographic Assessment of the Residual Filling Volume, Apical Transportation, and Crack Formation after Retreatment with Reciproc and Reciproc Blue Systems in Curved Root Canals.

INTRODUCTION: The purpose of the present study was to evaluate the remaining root canal filling material, apical transportation, and crack formation after retreatment with M-Wire Reciproc (VDW GmbH, Munich, Germany) and Reciproc Blue (VDW GmbH) systems in curved root canals. METHODS: Twenty-six mandibular first and second molars with mesial roots that had 2 separate canals with angles between 20° and 40° were selected for this study. The root canals were prepared with M-Wire Reciproc size 25 instruments (VDW GmbH), and they were filled with gutta-percha and AH Plus sealer (Dentsply Sirona, Tulsa, OK). The samples were randomly divided into 2 groups (n = 13 each) according to the retreatment system used: an M-Wire Reciproc group and a Reciproc Blue group. The canals were retreated up to instrument size 25 and then to size 40 in both groups. After the retreatment procedures, the residual filling material volume, apical transportation, and crack formation were assessed using micro-computed tomographic imaging. RESULTS: There were no significant differences between the groups in the amount of residual filling material (P > .05). The apical canal transportation values were significantly higher in the M-Wire Reciproc group than in the Reciproc Blue group at 1 mm. No significant differences were observed between the groups at any of the other levels with regard to apical transportation (P > .05) The new uncompleted and completed cracks were observed in both groups. There were no statistically significant differences between the groups in terms of crack and fracture formation (P > .05). CONCLUSIONS: The Reciproc Blue system is as effective as the M-Wire Reciproc system in terms of the retreatment of the curved mesial roots of mandibular molars. However, the formation of new uncompleted and completed cracks was found during the retreatment procedures.

Effects of continuous irrigation at room temperature or +4ºC on the cyclic fatigue resistance of K3XF instruments.

Background. The present study aimed to evaluate the impact of continuous irrigation with saline solution at room temperature or +4°C on the cyclic fatigue resistance of K3XF files. Methods. Forty-eight new K3XF files (#30, .04 taper) were randomly assigned to three groups: control group (no irrigation), continuous irrigation with saline solution at room temperature, and continuous irrigation with saline solution at +4°C. The instruments were tested in an artificial, stainless steel root canal with a double curvature at body temperature (37±1°C). Time to fracture was converted to the number of cycles to fracture (NCF). The lengths of the fractured fragments were recorded. Kruskal-Wallis H test and one-way ANOVA were used to analyze data. Results. K3XF files' cyclic fatigue resistance was significantly higher in the continuous irrigation groups than in the control group. Continuous irrigation with saline solution at +4°C resulted in higher cyclic fatigue resistance than continuous irrigation with saline solution at room temperature. There were no significant differences between the groups in terms of the fractured fragments' length. Conclusion. Within this study's limitations, continuous irrigation with saline solution increased the NCF of NiTi instruments; decreasing the saline solution's temperature increased this effect.

Effect of Calcium Hydroxide Alone or in Combination with Ibuprofen and Ciprofloxacin on Nuclear Factor Kappa B Ligand and Osteoprotegerin Level in Periapical Lesions: A Randomized Controlled Clinical Study.

INTRODUCTION: The aim of the present study was to evaluate the effects of calcium hydroxide (Ca[OH]2), Ca(OH)2 + ibuprofen, and Ca(OH)2 + ciprofloxacin in terms of receptor activator of nuclear factor kappa B ligand (RANKL) and osteoprotegerin (OPG) levels in asymptomatic periapical lesions. METHODS: Sixty-six patients were randomly divided into 3 groups using a Web program according to the medication selected: Ca(OH)2, Ca(OH)2 + ibuprofen, and Ca(OH)2 + ciprofloxacin. After removing gutta-percha from the root canals, the RANKL and OPG samples were taken from the interstitial fluid of the apical tissues using 3 paper points. At the second appointment, medicaments were removed, and second sampling was performed using the same method. The RANKL and OPG levels were measured by the enzyme-linked immunosorbent assay, and the RANKL/OPG ratio was calculated. RESULTS: According to the intragroup analysis, there were no statistically significant differences between the preoperative and postoperative levels of the RANKL/OPG ratio in any of the groups. Intergroup analyses showed that there were no statistically significant differences among the Ca(OH)2, Ca(OH)2 + ibuprofen, Ca(OH)2 + ciprofloxacin groups in terms of the percentage change in RANKL/OPG levels before and after treatment. CONCLUSIONS: Within the limitations of the present study, it can be concluded that addition of ibuprofen or ciprofloxacin to Ca(OH)2 paste does not provide any extra benefit in terms of lowering RANKL and OPG levels.

Comparison of the cyclic fatigue resistance of ProGlider, PathGlider and One G path-finding instruments.

Background . The aim of the present study was to compare the cyclic fatigue resistance of novel nickel titanium rotary pathfinding instruments. Methods . Twenty instruments were selected for each file system. A simulated stainless steel root canal, with a 90° angle of curvature and a curvature radius of 3 mm, was used for cyclic fatigue test of the ProGlider (#16, progressive taper: 0.02‒ 0.085), PathGlider (#15, taper: .03), and One G (#14, taper: .03) instruments. Statistical analyses were performed with oneway ANOVA (P=0.05). Post hoc Tukey tests were used to determine any statistically significant differences between the groups. Results . The ProGlider instruments exhibited significantly more cyclic fatigue resistance than both PathGlider and One G instruments (P<0.001). One G instruments had significantly more resistance to fracture than PathGlider instruments (P<0.05). Conclusion . ProGlider instruments had better cyclic fatigue resistance than PathGlider and One G instruments.

Effect of the Simultaneous Working Length Control during Root Canal Preparation on Postoperative Pain.

AIM: The aim of this study was to evaluate the effect of simultaneous length control during root canal preparation on postoperative pain compared with separate working length determination and root canal preparation. The design was a parallel-group, randomized, controlled trial with 2 arms. METHODS: Forty-four molar teeth were randomly divided into 2 groups (n = 22), a control group (separate length determination and root canal preparation) and a simultaneous length control during root canal preparation group. The following variables were recorded: age; gender; tooth number; preoperative pain on the visual analog scale; pain level on days 1, 3, 5, and 7; and analgesic intake after the procedure and initial/final percussion pain. The data were analyzed with the χ2 test, independent samples t test, and Mann-Whitney U test. RESULTS: The simultaneous length control during root canal preparation group resulted in lower postoperative pain levels on day 1 than did the control group (P < .05). Despite 2 patients' intake of postoperative analgesics in the control group, no patient needed to use postoperative analgesics in the simultaneous length control during root canal preparation group (P > .05). CONCLUSIONS: Simultaneous length control during root canal preparation as a non-pharmacologic strategy for reducing postoperative pain is a beneficial technique for preventing postoperative pain.