The effect of antibiotic use on endodontic post-operative pain and flare-up rate: a systematic review with meta-analysis.

Aim Antibiotics are widely used to prevent flare-ups after endodontic treatment of non-vital teeth. This systematic review assessed the effect of antibiotic administration on post-endodontic treatment pain and flare-up rate.Methods Five major databases including Web of Science, Cochrane Library, PubMed, Scopus and Embase were searched to identify randomised clinical trials (RCTs) published until September 2020. Retrieved papers were critically appraised using the revised Cochrane risk of bias tool (RoB 2). To reduce the clinical heterogeneity, the included studies were divided into two groups: studies on symptomatic non-vital teeth and studies on asymptomatic non-vital teeth. The primary outcomes were 'post-operative pain' and 'flare-up rate'. The data of included studies were statistically combined through meta-analysis using random-effect model. The Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach was used to assess the quality of evidence.Results Six RCTs involving two RCTs (N = 61) on symptomatic teeth and four RCTs (N = 310) on asymptomatic teeth were included. In two RCTs on asymptomatic teeth, prophylactic antibiotic had been used, while in the remaining two RCTs, antibiotics had been administered after treatment. Quantitative synthesis of the RCTs showed that antibiotic administration following endodontic treatment of symptomatic non-vital teeth has no effect on pain severity at 24 hours following treatment (weighted mean difference [WMD] = -0.03; 95% confidence interval [CI]: -0.53 to 0.47), and the use of antibiotics before endodontic treatment of asymptomatic non-vital teeth has no effect on flare-up rate (relative risk [RR] = 0.58; 95% CI: 0.22-1.54). The GRADE approach revealed that the overall quality of evidence on the topic is low.Conclusions The antibiotic administration following endodontic treatment of symptomatic non-vital teeth has no effect on pain severity at 24 hours following treatment. Also, prophylactic antibiotics are ineffective in reducing the flare-up rate following treatment of asymptomatic non-vital teeth. However, to evaluate the effect of post-treatment antibiotics on flare-up rate in asymptomatic non-vital teeth, more high-quality RCTs are needed.

Volume of Anesthetic Agents and IANB Success: A Systematic Review.

The aim of this study was to provide an evidence-based answer to the question: "Is 3.6-mL volume of an anesthetic agent more effective than 1.8-mL volume in providing anesthesia for mandibular molars?" Following formulation of research question and keyword selection, a comprehensive search of the following databases was conducted: Cochrane library, PubMed, Scopus, Google Scholar, ProQuest, and Clinicaltrials.gov. Three-phase eligibility appraisal and quality assessment of the studies were carried out by 2 independent reviewers. To reduce clinical heterogeneity, the included studies were divided into 2 groups: studies on healthy teeth and studies on teeth with pulpitis. The data of included studies were statistically combined through meta-analysis using a fixed-effects model. A total of 20,778 records were initially retrieved from the search. Following screening and eligibility assessment, 8 studies met the eligibility criteria and were included for qualitative synthesis. Of those, 5 studies were qualified for meta-analysis. In the irreversible pulpitis group, increasing the volume of anesthetic agent from 1.8 to 3.6 mL significantly increased the success rate of inferior alveolar nerve block (risk ratio = 2.45, 95% CI: 1.67-3.59, p < .001). However, there was insufficient evidence to draw a conclusion regarding healthy teeth.

Effect of electric currents on antibacterial effect of chlorhexidine against Entrococcus faecalis biofilm: An in vitro study.

BACKGROUND: This in vitro study was mainly aimed to evaluate the effect of high-frequency alternating currents (AC) applied by an electronic apex locator (EAL) on the antibacterial properties of chlorhexidine (CHX) on E. faecalis biofilm. MATERIAL AND METHODS: The root canals of 120 extracted human single-rooted teeth were prepared using Gates-Glidden drills and hand K-files. After contaminating the root canals with E. faecalis, they were incubated for 60 days. Then, the teeth were randomly divided into six experimental groups (n=20). Group 1, 2% CHX; group 2, normal saline (NS) with direct current (DC); group 3, normal saline (NS) with high-frequency alternating current (AC); group 4, 2% CHX with DC; group 5, 2% CHX with AC; group 6, control (normal saline). The samples were collected from the root canal walls of 16 teeth in each group and 1:10 serial dilutions were prepared and added to Muller-Hinton agar (MHA) plates and incubated at 37°C for 48 h. The longitudinal sections of the other 4 teeth used to observe under a scanning electron microscope (SEM). A classic colony counting technique was used for counting the vital E. faecalis bacteria in MHA. Two-way ANOVA was used for statistical analysis of the data. The level of significance was set at P<0.05. RESULTS: The electric current significantly changed the colony-forming units (CFU) values (P<0.001). According to pair-wise comparisons, the highest CFU difference was observed between the AC group and the group without electric current (P<0.001); furthermore, the difference between the DC group and the group without electric current was not significant (P=0.823). CONCLUSIONS: The highest bioelectric effect occurred with the use of high-frequency alternating electric current in the form of an apex locator with CHX as a canal irrigant. Key words:Biofilm, Chlorhexidine, Direct current, Electric current, Enterococcus faecalis.

Effect of Topical Anesthesia with Lidocaine-prilocaine (EMLA) Cream and Local Pressure on Pain during Infiltration Injection for Maxillary Canines: A Randomized Double-blind clinical trial.

OBJECTIVES: This study compared the effect of local pressure and topical lidocaine-prilocaine (EMLA) cream on pain during infiltration injection for maxillary canine teeth. MATERIALS AND METHODS: A total of 140 volunteer students participated in this split-mouth design randomized clinical trial. The subjects were randomly divided into four groups (n = 35). Before administration of anesthesia, in each group, one side was randomly selected as the experimental and the opposite side as the control. In group 1, finger pressure was applied on the alveolar mucosa on the experimental side and on the tooth crown on the control side. In group 2, 5% EMLA cream and placebo; in group 3, finger pressure and 5% EMLA cream; and in group 4, 5% EMLA cream and 20% benzocaine gel were applied. In all the groups, a buccal infiltration procedure was carried out. Pain during injection was recorded with visual analog scale (VAS). Wilcoxon and McNemar tests were used for statistical analysis of the results. Statistical significance was set at p < 0.05. RESULTS: The results showed that EMLA reduced the injection pain significantly more than benzocaine (p = 0.02). Also, injection pain was significantly lower with the use of EMLA in comparison to placebo (p = 0.00). Application of local pressure reduced the injection pain, but the difference from the control side was not significant (p = 0.05). Furthermore, the difference between application of local pressure and EMLA was not statistically significant (p = 0.08). CONCLUSION: Topical anesthesia of 5% EMLA was more effective than 20% benzocaine in reducing pain severity during infiltration injection. However, it was not significantly different in comparison to the application of local pressure.

Antimicrobial activity of tetraacetylethylenediamine-sodium perborate versus sodium hypochlorite against Enterococcus faecalis.

Background. This study evaluated the antimicrobial activity of Tetraacetylethylenediamine-sodium perborate (TAED-SP) in comparison to 2.5% and 5% sodium hypochlorite (NaOCl) against Enterococcus faecalis. Methods. A standard suspension of E. faecalis was inoculated on 60 plates containing Mueller-Hinton agar culture medium. Four sterile disks of Beckman filtration paper were placed on each plate. TAED-SP, 5% and 2.5% NaOCl were placed on three disks. Sterile physiologic saline was placed on the fourth disk as negative control. After 24-hour incubation, the diameter of the inhibition zone around the disks was measured using a transparent ruler. One-way Analysis of Variance (ANOVA) was used to compare the mean zone of microbial growth in the groups. P-values less than 0.05 were considered statistically significant. Results. There was a significant difference in the diameter of the inhibition zones between groups (P < 0.05). The Tukey post hoc test showed a higher diameter of the inhibitory zone with TAED-SP than that of 2.5% NaOCl. However, there were no significant differences between the inhibitory zones of TAED-SP and 5% NaOCl. Conclusion. TAED-SP and 5% NaOCl have similar antibacterial activity against E. faecalis; however, TAED-SP has a greater antibacterial effect compared to 2.5% NaOCl.

The effect of temporary restorative materials on fracture resistance of endodontically treated teeth.

This study was designed to investigate the fracture strength of endodontically treated teeth temporarily restored with some commonly used interim materials. Of 90 extracted maxillary premolars used in this study, 15 were left intact as the positive control. Endodontic treatment was performed on the remaining 75 teeth. The endodontically treated teeth were then randomly assigned to 5 groups (n = 15). One group was not restored and served as the negative control. In the remaining 4 experimental groups, the teeth were restored with a temporary cement: Zonalin, IRM, Coltosol, or Fuji II LC resin-modified glass ionomer (RMGI). The fracture strengths of all teeth were measured with a universal testing machine. The fracture strength of teeth restored with RMGI was significantly greater than that of other groups (P < 0.001), including intact teeth (P = 0.025). The fracture strength of teeth restored with other temporary materials was significantly lower than that of intact teeth (P < 0.05) but not significantly different from that of the negative control. From a structural resistance standpoint, RMGI may be the best choice for short-term temporary restoration of endodontically treated teeth. Other types of temporary restorative material had no reinforcing effect on tooth structure.

Effect of Blood Contamination on Marginal Adaptation and Surface Microstructure of Mineral Trioxide Aggregate: A SEM Study.

BACKGROUND AND AIMS: In various clinical situations, mineral trioxide aggregate (MTA) may come into direct contact or even be mixed with blood. The aim of the present study was to evaluate the effect of exposure to blood on marginal adaptation and surface microstructure of MTA. MATERIALS AND METHODS: Thirty extracted human single-rooted teeth were used. Standard root canal treatment was carried out. Root-ends were resected, and retrocavities were prepared. The teeth were randomly divided into two groups (n = 15): in group 1, the internal surface of the cavities was coated with fresh blood. Then, the cavities were filled with MTA. The roots were immersed in molds containing fresh blood. In group 2, the aforementioned procedures were performed except that synthetic tissue fluid (STF) was used instead of blood. To assess the marginal adaptation, "gap perimeter" and "maximum gap width" were measured under scanning electron microscope. The surface microstructure was also examined. Independent samples t-test and Mann-Whitney U test were used to analyze the data. RESULTS: Maximum gap width and gap perimeter in the blood-exposed group were significantly larger than those in the STF-exposed group (p < 0.01). In the blood-exposed group, the crystals tended to be more rounded and less angular compared with the STF-exposed group, and there was a general lack of needle-like crystals. CONCLUSION: Exposure to blood during setting has a negative effect on marginal adaptation of MTA, and blood-exposed MTA has a different surface microstructure compared to STF-exposed MTA.

Mixing with propylene glycol enhances the bond strength of mineral trioxide aggregate to dentin.

INTRODUCTION: Mixing mineral trioxide aggregate (MTA) with different proportions of propylene glycol (PG) improves its handling property. The aim of this study was to evaluate the effect of PG on MTA-dentin push-out bond strength. METHODS: Seventy-five 2-mm-thick midroot sections were prepared from single-rooted human extracted teeth. The lumen of each slice was enlarged with Gates-Glidden burs. The slices were randomly divided into 3 groups (n = 25). In each group, 0.3 mL of the liquid was mixed with 1 g MTA (Angelus, Londrina, Brazil). The liquid vehicles used in groups 1-3 were 100% distilled water (DW), 20% PG-80% DW, and 100% PG, respectively. After incubation, the push-out strength of the samples was measured using a universal testing machine. The samples were then cut in halves and examined under a stereomicroscope to determine the failure pattern. One-way analysis of variance followed by the Tukey post hoc test was used to compare the push-out strength among groups. RESULTS: There were statistically significant differences between groups (P < .001). The push-out strength in group 1 (DW) was significantly lower than groups 2 and 3 (P < .001 and P = .022, respectively). However, there was no significant difference between groups 2 (DW-PG) and 3 (PG). CONCLUSIONS: Mixing MTA with PG increased its push-out bond strength to dentin. In the present study, the most suitable ratio was 80% DW-20% PG.

Treatment of Strip Perforation Using Root MTA: A Case Report.

Root perforations are an undesired complication of endodontic treatment which result in loss of integrity of the root, and adversely affect the prognosis of the treatment. Recently, Iranian mineral trioxide aggregate [Root MTA] has been introduced as an ideal material for perforation repair. In this article a successful repair of strip root perforation of mandibular molar using Root MTA is presented with 15-month follow-up. This case suggests that Root MTA may be a substitute material for the treatment of strip perforation; however, more clinical studies with larger sample size and longer follow-ups are needed.

Effect of blood contamination on the retention characteristics of two endodontic biomaterials in simulated furcation perforations.

INTRODUCTION: The aim of the present study was to compare the effect of blood contamination on retention characteristics of white mineral trioxide aggregate (WMTA) and calcium-enriched mixture (CEM) in reconstructions of the furcation area. METHODS: Furcal perforations, measuring 1.3 mm in diameter and 2 mm in height, were produced in 180 human mandibular first molars. The teeth were divided into 12 groups of 15. WMTA and CEM were used in groups 1-6 and 7-12, respectively, for perforation repair. In groups 1, 3, 5, 7, 9, and 11 the walls of the perforated area were contaminated with blood; normal saline was injected in the remaining groups. Push-out test was carried out in groups 1, 2, 7, and 8 after 24 hours, in groups 3, 4, 9, and 10 after 72 hours, and in the remaining groups 7 days after placement of the materials by using a Universal test machine. To evaluate the failure modes, the samples were sectioned at furcation floor area, divided in two in the vertical direction, and evaluated under a stereomicroscope at × 40 magnification. Data were analyzed with multivariate analysis of variance and post hoc Tukey tests. RESULTS: The highest (6.75 MPa) and lowest (1.77 MPa) bond strength values were recorded in groups CEM/no blood contamination at 7 days and MTA/blood contamination at 24 hours, respectively. There were no statistically significant differences in bond strength between MTA and CEM (P < .05). However, there were significant differences in bond strength between blood-contaminated and uncontaminated groups in both materials (P < .05); time had exerted a significant effect on the bond strength of the study groups (P < .05). Failure patterns were of the mixed type in all the samples. CONCLUSIONS: Resistance of both WMTA and CEM to displacement was similar, and elapse of time from 24 hours to 7 days and contamination resulted in an increase and decrease in bond strength of these 2 materials to dentin, respectively.

The effect of root canal preparation on the development of dentin cracks.

INTRODUCTION: Root fracture is not an instant phenomenon but a result of gradual development of tiny craze lines in tooth structure. Recent studies have shown that canal instrumentation has the potential to cause dentinal cracks. The purpose of this study was to evaluate and compare the formation of dentinal cracks caused by ProTaper rotary system to hand instrumentation. MATERIALS AND METHODS: This in vitro study was carried out using 57 mandible incisor teeth. The teeth were decoronated. The roots were then examined to exclude cracked samples. A standard model for PDL simulation was used. The teeth were randomly divided into two experimental and one control group (n=19). The teeth in the experimental groups were prepared using hand or ProTaper Universal rotary instrumentation. The teeth in the control group were left unprepared. The teeth were then sectioned horizontally 3 and 6 mm from the apex, and the number of various dentinal defects was recorded using a dental operating microscope. The differences between groups were analyzed with Fisher's exact test. RESULTS: The hand group demonstrated significantly more defects than the control group (P=0.001). However, there was no significant difference between the rotary compared to the control and hand groups (P>0.05). There was no significant difference between groups with regards to fracture (P>0.05). Other defects including internal, external and surface cracks were more frequent in the hand than in the control or rotary groups (P=0.02), but the difference was not significant between the rotary and control groups (P>0.05). CONCLUSION: Canal preparation, whether hand or rotary, produces structural defects in dentin. The ProTaper rotary system when used according to the manufacturer's instructions, tends to produce fewer cracks and can be considered a safe preparation technique.

Bactericidal effects of Nd:YAG laser irradiation and sodium hypochlorite solution on Enterococcus faecalis biofilm.

OBJECTIVE: The aim of this study was to evaluate the bactericidal effects of Nd:YAG laser on biofilm of Enterococcus faecalis. BACKGROUND DATA: It is difficult to eliminate bacterial biofilms with routine endodontic preparation techniques. It might be possible to eliminate biofilms remaining in the root canals of teeth with lasers. MATERIALS AND METHODS: The root canals of 60 extracted teeth were prepared and E. faecalis biofilms were formed within the root canals. Then the teeth were randomly divided into four groups of 15. Group 1 samples did not undergo any interventions, to serve as controls. Group 2 samples underwent a 3-W laser beam for 10 sec. The root canals in group 3 were irrigated with 1% sodium hypochlorite for 15 min and then irradiated with a 3-W laser beam for 10 sec. The root canals in group 4 were irrigated with 1% sodium hypochlorite for 15 min. Dentin chips were collected from the root canal walls and weighed. Then the chips were used to prepare a suspension. The classic colony-forming unit (CFU) counting technique was used to determine remaining bacterial counts. RESULTS: The bacterial counts in groups 2 and 4 had decreased to 54% and 2.39% of the control group, respectively. In group 3 no bacterial growth was observed. There were no significant differences between groups 1 and 2 (p>0.05). CONCLUSIONS: Based on the results of the present study, the effect of Nd:YAG laser beam on E. faecalis biofilm is less than that of sodium hypochlorite solution. A combination of laser and sodium hypochlorite results in complete elimination of E. faecalis biofilm.