Evaluation of the accuracy of two apex locators in endodontic treatment and retreatments: an ex vivo study

Introduction: Working length determination is important in successful endodontic treatment and retreatment. This study evaluated the accuracy of two electronic apex locators Root ZX and Raypex®6 (EALs) in determining the electronic working length (EWL) of the root canals in endodontic treatment and retreatment. Materials &Methods: Access cavities were prepared on forty extracted, single-rooted human teeth and the actual working length (AWL) of the canals was determined. In the first phase of the study, primary EWL of un-instrumented teeth was measured and compared between two EALs. In phase II, all of the teeth were pre-flared and divided into the control (n=10) and the retreatment groups (n=30). Canals in the retreatment group were obturated by the lateral condensation technique using Gutta percha and sealer. After 15 days, gutta-percha was removed, and then the secondary EWL was recorded and compared between the two devices, in treatment and retreatment groups. Data were analysed by paired t-test and t-test. Results: Significant differences were found between both EALs in treatment and retreatment phases of the study (p<0.001). Both EALs showed increased accuracy in retreatment group (p<0.001). However, no statistically significant differences were found between the control and retreatment groups in the second phase of the study for Root ZX (p=0.929), and Raypex®6 (p=0.937). Conclusion: Accuracy of the two EALs was similar and acceptable. EWLs determined by Root ZX were closer to the AWL. The EWL determination after pre-flaring improved the accuracy of EALs and root canal obturation remnant materials did not have any clear effect on the accuracy of these EALs

Effect of 4% articaine and 2% lidocaine both with 1:100,000 epinephrine on hemodynamic changes in impacted mandibular third molar surgery: prospective, double-blinded, randomized clinical trial

Hemodynamic effect of local anestheticshould be investigated to prevent unwantedcomplications. The presentstudy assessed the hemodynamic alterations after injectingtwo of the most commonly used local anestheticformulations for impacted mandibular third molar surgery.A prospective, double-blinded, randomized clinicaltrial were designed, and patients that attended theoral and maxillofacial surgery department for surgicalremoval of impacted mandibular third molar were askedto participate. Patients were divided into two groups andrandomly received one of the two interventions; 2% lidocainewith 1:100,000 epinephrine (LE) and group 2: 4%articaine with 1: 100,000 epinephrine (AE). Pulse rate,oxygen saturation, and systolic/diastolic blood pressurewere assessed at three different times: before the procedure,five minutes after injecting local anesthetics, andafter finishing the surgery. Eighty patients between theage of 18 to 45 years old participated in the study which44 (55%) were female, and 36 (45%) male. The pulserate significantly increased when comparing three differentmeasurement intervals for each local anesthetic.Oxygen saturation in the LE group was statistically differentcomparing each interval, but there was no significantdifference in the AE group. There were changes insystolic and diastolic blood pressure at each measurementpoint, but it was not statistically significant. Therewas no significant difference in hemodynamic changesbetween the two groups. Hemodynamic alteration afterlocal anesthetic administration should be expected. Thetwo formulations were safe and showed no statisticallysignificant hemodynamic changes in healthy patients

Fracture resistance of upper central incisors restored with different posts and cores

Objectives To determine and compare the fracture resistance of endodontically treated maxillary central incisors restored with different posts and cores. Materials and Methods Forty-eight upper central incisors were randomly divided into four groups: cast post and core (group 1), fiber-reinforced composite (FRC) post and composite core (group 2), composite post and core (group 3), and controls (group 4). Mesio-distal and bucco-lingual dimensions at 7 and 14 mm from the apex were compared to ensure standardization among the groups. Twelve teeth were prepared for crown restoration (group 4). Teeth in other groups were endodontically treated, decoronated at 14 mm from the apex, and prepared for posts and cores. Resin-based materials were used for cementation in groups 1 and 2. In group 3, composite was used directly to fill the post space and for core build-up. All samples were restored by standard metal crowns using glass ionomer cement, mounted at 135° vertical angle, subjected to thermomechanical aging, and then fractured using a universal testing machine. Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data. Results Fracture resistance of the groups was as follows: Control (group 4) > cast post and core (group 1) > fiber post and composite core (group 2) > composite post and core (group 3). All samples in groups 2 and 3 fractured in restorable patterns, whereas most (58%) in group 1 were non-restorable. Conclusions Within the limitations of this study, FRC posts showed acceptable fracture resistance with favorable fracture patterns for reconstruction of upper central incisors

Comparison of Apical Extrusion of Debris by Using Single-File, Full-Sequence Rotary and Reciprocating Systems

Objectives: During root canal preparation, apical extrusion of debris can cause inflammation, flare-ups, and delayed healing. Therefore, instrumentation techniques that cause the least extrusion of debris are desirable. This study aimed to compare apical extrusion of debris by five single-file, full-sequence rotary and reciprocating systems. Materials and Methods: One hundred twenty human mandibular premolars with similar root lengths, apical diameters, and canal curvatures were selected and randomly assigned to six groups (n=20): Reciproc R25 (25, 0.08), WaveOne Primary (25, 0.08), OneShape (25, 0.06), F360 (25, 0.04), Neoniti A1 (25, 0.08), and ProTaper Universal. Instrumentation of the root canals was performed in accordance with the manufacturers’ instructions. Each tooth's debris was collected in a pre-weighed vial. After drying the debris in an incubator, the mass was measured three times consecutively; the mean was then calculated. The preparation time by each system was also measured. For data analysis, one-way ANOVA and Games-Howell post hoc test were used. Results: The mean masses (±standard deviation) of the apical debris were as follows: 2.071±1.38mg (ProTaper Universal), 1.702±1.306mg (Neoniti A1), 1.295±0.839mg (OneShape), 1.109±0.676mg (WaveOne), 0.976±0.478mg (Reciproc) and 0.797±0.531mg (F360). Compared to ProTaper Universal, F360 generated significantly less debris (P=0.02). The ProTaper system required the longest preparation time (mean=88.6 seconds); the Reciproc (P=0.008), OneShape (P=0.006), and F360 (P=0.001) required significantly less time (P<0.05). Conclusions: All instruments caused extrusion of debris through the apex. The F360 produced significantly less debris than did the ProTaper Universal

Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets

Objectives: White spots and enamel demineralization around orthodontic brackets are among the most important complications resulting from orthodontic treatments. Since the antibacterial properties of metals and metallic particles have been well documented, the aim of this study was to assess the antibacterial effect of stainless steel orthodontic brackets coated with silver (Ag) particles. Materials and Methods: In this study, 40 standard metal brackets were divided into two groups of 20 cases and 20 controls. The brackets in the case group were coated with Ag particles using an electroplating method. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to assess the adequacy of the coating process. In addition, antibacterial tests, i.e., disk diffusion and direct contact tests were performed at three, six, 24and 48 hours, and 15 and 30 days using a Streptococcus mutans strain. The results were analyzed using Student’s t-test and repeated measures ANOVA. Conclusions: Brackets coated with Ag, via an electroplating method, exhibited antibacterial properties when placed in direct contact with Streptococcus mutans. This antibacterial effect persisted for 30 days after contact with the bacteria

Influence of operator's experience level on lifespan of the WaveOne Primary file in extracted teeth

Objectives The aim of this study was to assess the influence of operator experience level on the lifespan of the WaveOne Primary file (Dentsply Maillefer, Ballaigues, Switzerland) in extracted teeth. Materials and Methods Moderately curved canals of extracted maxillary and mandibular molars were randomly distributed into 2 groups: experienced and inexperienced operators. Ten files were allocated to each group (n = 10). Each canal was prepared until the working length was reached, and the same file was used to prepare additional canals until it separated. The number of canals prepared before file separation was recorded. The fragment length of each file was measured, and the location of the fragment in the canal was determined. Data were statistically analysed using the independent 2-sample t-test. Results The 2 operators prepared a total of 324 moderately curved canals of maxillary and mandibular molars. There was no significant intergroup difference in the mean number of canals prepared (p = 0.27). The average lifespan of the WaveOne Primary file was 17.1 and 15.3 canals, and the longest lifespan was 25 and 20 canals, when used by experienced and inexperienced operators, respectively. There were no statistically significant intergroup differences in separated fragment length and location. Conclusions Within the limitations of this study, operator experience level appears to have no effect on the lifespan of the WaveOne Primary file in preparation of moderately curved canals. Single teeth with multiple canals can be prepared safely even by a novice operator by using a single file