Lucila Piasecki

Accuracy of Root ZX II in Locating Foramen in Teeth with Apical Periodontitis: An In Vivo Study

INTRODUCTIONnThis study was conducted in vivo to investigate the accuracy of Root ZX II in locating the apical foramen in teeth with apical periodontitis (AP).nnnMETHODSnTwenty-seven single-root teeth scheduled for extractions were selected; in AP group, there were 12 teeth with pulp necrosis and radiographic evidence of apical lesions, and VT group consisted of 15 vital teeth. After endodontic access, the coronal portion of the canal was flared, and electronic measurement was performed by using a 15 K-file until the device level reading APEX was reached. The file was fixed in place, and the tooth was extracted. The apical third of the root was shaved until exposure of the file. The distance from the file tip to the most coronal border of the apical foramen was obtained.nnnRESULTSnThe mean distance in AP group was +0.117 (standard deviation, 0.373) and in VT group was -0.105 (standard deviation, 0.218). The unpaired t test showed no difference between the groups when comparing the mean distances (P > .05). The apical foramen was accurately located within ±0.5 mm in 83% of the teeth in AP group and in 100% of VT group. Statistical analysis showed no difference between the groups (P = .1092).nnnCONCLUSIONSnThe Root ZX II device was accurate in locating the apical foramen regardless of the presence of AP.

Cyclic fatigue of instruments for endodontic glide path.

Endodontic glide path is the creation of a smooth patency from canal orifice to apex, which can be performed manually or with small tapered NiTi rotary instruments. The use of stainless steel (SS) hand K-files inserted in a reciprocating handpiece can be a possible alternative to create a mechanical glide path. The aim of this study was to compare the cyclic fatigue resistance between SS K-files used in a reciprocating motion and NiTi rotary instruments in artificial curved canals. Ten SS size 15xa0K-files used with the M4 handpiece (SybronEndo, Glendora, CA, USA) and ten PathFiles (Maillefer-Dentsply, Ballaigues, CH, Switzerland) NiTi rotary instruments size 16, 0.02 taper were tested for resistance to cyclic fatigue. The time to fracture inside an artificial curved canal was recorded for each instrument. Data were analyzed by one-way ANOVA and Tukey HSD test. Mean time (and SD) to failure was 464xa0s (±40.4) for the Group PF (NiTi rotary PathFile), and 1049xa0s (±24.8) for the Group M4 (SS K-files reciprocating) with a statistically significant difference between the two groups (pxa0=xa00.033). The SS 15xa0K-files used with the M4 handpiece showed a significant greater resistance to cyclic fatigue when compared to the NiTi rotary PathFiles. Therefore, the use of small size SS files in a reciprocating motion might be a rational choice for the creation of a mechanical endodontic glide path in curved root canals.

The Use of Micro-Computed Tomography to Determine the Accuracy of 2 Electronic Apex Locators and Anatomic Variations Affecting Their Precision.

INTRODUCTIONnThe aim of this study was to compare the accuracy of 2 electronic apex locators (EALs), Apex ID (SybronEndo, Glendora, CA) and Root ZX (J. Morita, Tokyo, Japan), by means of micro-computed tomographic (micro-CT) imaging and to determine anatomic variations that may affect their accuracy.nnnMETHODSnThe root canal length (RCL) and working length (WL) of 33 single-rooted premolars were measured using a visual method, 3-dimensional micro-CT reconstructions, and 2 different EALs. Two different measurements were recorded for each EAL: at the APEX/0.0 mark and at the 0.5 mark. The WL was determined using 2 different methods: method 1: at the 0.5 mark of the apex locator and method 2: subtracting 0.5xa0mm from the APEX/0.0 mark. The precision of measurements was compared with those recorded by micro-CT imaging. Apical foramen (AF) position and diameter, apical constriction (AC) diameter, distance between the AC and the AF, and the presence/absence of accessory canals were recorded from the micro-CT scans, and their correlation to the accuracy of EALs was determined.nnnRESULTSnThere was no statistically significant difference in the RCL measurements by any of the different methods. There was a statistically significant difference in the WL recorded by micro-CT imaging compared with those by the visual method and at the APEX/0.0 mark - 0.5xa0mm (Pxa0=xa0.031). There was no difference in the measurements acquired by any of the EALs. The APEX/0.0 mark - 0.5xa0mm was less accurate than the 0.5 mark. However, the results were not statistically significant (Pxa0>xa0.05). The position of the AF and the AC-AF distance affected the accuracy of the RCL (Pxa0=xa0.003) and the 0.5 mark (Pxa0=xa0.013).nnnCONCLUSIONSnRoot ZX and Apex ID are equally precise in determining the RCL and WL. The 0.5 mark can be used to determine the WL with high precision. Some anatomic variations may influence the accuracy of EALs.

An in vivo evaluation of the Auto Apical Reverse function of the Root ZX II

AIMnTo evaluate in vivo the accuracy of the Root ZX II (J. Morita) apex locator in controlling the apical extent of rotary instrumentation when using the Auto Apical Reverse (AAR) set at the levels 0.5, 1.0 and 1.5.nnnMETHODOLOGYnThirty single-rooted premolar teeth scheduled for extraction were divided into three groups (n = 10), according to the AAR setting 0.5, 1.0 and 1.5. The root canals were prepared using ProTaper (Dentsply Maillefer). After rotary instrumentation, the last file used (F3) was manually introduced into the extent of the root canal preparation and fixed before tooth extraction. The apical third of the root was dissected until exposure of the file. The distance from the file tip to the major apical foramen was obtained.nnnRESULTSnMeasurements within the range -1.0 to 0.0 mm were obtained in 30% of the teeth with AAR 0.5, 50% with AAR 1.0 and in 0% with AAR 1.5. The proportions test revealed a significant difference between the AAR settings 1.0 and 1.5 (P = 0.0188). Overinstrumentation occurred in 70% of the teeth with AAR 0.5 and in 40% with AAR 1.0. The measurements short of the acceptable range occurred in 10% of the teeth with setting AAR 1.0 and in 100% of the cases with AAR 1.5. A significant difference was found when comparing the percentage of teeth in which the file tip was short and beyond the established range between groups, except when comparing AAR 0.5 and AAR 1.0.nnnCONCLUSIONnThe AAR function of the Root ZX II was not an accurate method for controlling the apical extent of rotary instrumentation in vivo. The setting 0.5 presented overinstrumentation in most of the canals, the setting 1.5 was short in all cases, and the setting 1.0 provided an adequate working length in only 50% of the teeth.

XP Shaper, A Novel Adaptive Core Rotary Instrument: Micro–computed Tomographic Analysis of Its Shaping Abilities

Introduction The aim of this study was to investigate the shaping abilities of the XP Shaper (FKG, La Chaux‐de‐Fonds, Switzerland) and compare the findings with Vortex Blue (Dentsply Tulsa Dental Specialties, Tulsa, OK) using micro–computed tomographic imaging. Methods Twenty matched, extracted, mandibular, central incisors with a single, oval canal were scanned preoperatively at 25‐&mgr;m resolution and postoperatively after instrumentation with either Vortex Blue in a crown‐down manner up to size 30.04 or XP Shaper. The percent of untouched walls, changes in canal volume and surface area, the amount of dentin removed, debris remaining in the canal, and the preparation taper were determined. The total time required for instrumentation using each technique was calculated in seconds. Statistical analysis was used to compare between both groups using repeated measures multivariate analysis of variance with Bonferroni correction for post hoc comparison and independent sample t tests. Results The XP Shaper significantly increased the canal volume (F = 77.948, P < .001), surface area (F = 5.543, P = .030), and amount of dentin removed (F = 10.044, P = .001) and had significantly less untouched walls (38.6% ± 8.1%) compared with VB (58.8% ± 8.5%). There was less debris at all levels of the canal in the XP Shaper group. Results were almost significant (P = .059). The XP Shaper was also significantly faster in completing the mechanical preparation of the root canal space by almost 1 minute (t = 6.216, P < .001). Conclusions The XP Shaper can expand beyond its core size to adapt to the anatomy of the root canal space. The XP Shaper can prepare and touch more canal walls in oval‐shaped canals compared with Vortex Blue. However, the final preparation taper will vary according to the anatomy of the treated tooth. HighlightsThe XP Shaper represents a new generation of rotary files that can expand beyond its core size.The XP Shaper can touch more canal walls than Vortex Blue in oval‐shaped canals.Mechanical preparation of the canal can be completed with the XP shaper in a shorter duration compared with Vortex Blue.The final preparation taper of the XP Shaper will vary from one case to the other depending on the original canal anatomy.

A preliminary assessment of a new dedicated endodontic software for use with CBCT images to evaluate the canal complexity of mandibular molars

AIMnTo investigate inxa0vivo the complexity of canals within mesial roots of mandibular molars using 3D Endo™ software linked to CBCT images.nnnMETHODOLOGYnThe CBCT images of 100 mandibular first molars were analysed using the 3D Endo™ software. The number of canals in the mesial roots, the presence of apical confluences, the canal lengths and the canal configurations using Vertuccis classification were evaluated in buccolingual (BL) and mesiodistal (MD) views. The software allowed the visualization of canal trajectories in three dimensions using a coloured outline, which was used to develop a new objective scoring system to provide an overall assessment of canal complexity. Data were analysed statistically using anova and t-tests with the significance set at Pxa0<xa00.05.nnnRESULTSnVertucci type IV canals were found in 44% of the cases, whilst 54% were type II. The mean distance from the apical foramen to the orifice was 13.15xa0mm (±1.21) and that between a confluence and the foramen, 2.81xa0mm (±1.13). The number of curvatures and the canal complexity scores in the MD view were significantly higher than in the BL view (Pxa0<xa00.05). The scores were not directly correlated to the canal (MB versus ML), to the canal length or to the presence of confluences.nnnCONCLUSIONSn3D Endo software features the automatic detection and measurement of several anatomical canal parameters, and is a promising tool for the study of canal complexity inxa0vivo. The unpredictable anatomy of the mesial roots of mandibular molars highlights the value of a three-dimensional preoperative evaluation of each case. The proposed scoring system aims to provide the clinician with an overall assessment of canal complexity.

Efficacy of protaper instruments during endodontic retreatment

Introduction: The effectiveness of ProTaper Universal and ProTaper Retreatment rotary instruments was compared to the Hedström files in the removal of filling material from root canals. Materials and Methods: Thirty-six extracted human mandibular premolars with a single straight root canal were shaped and filled with gutta-percha and AH Plus. The specimens were stored for 6 months at 37°C and at 100% relative humidity, and then randomly divided into three groups: PTU - removal of filling material performed with ProTaper Universal instruments; PTR - removal of filling material performed with ProTaper Retreatment instruments; HF – removal of filling material performed with Gates-Glidden burs, Hedström files and solvent. After the filling material removal and diaphanization, the specimens were longitudinally sectioned and images of the canal surfaces were scanned. The remaining areas of filling material were measured (Image Tool 3.0), and data was analyzed statistically (Kruskal-Wallis and Dunn tests). The time required for filling removal in each group was also recorded (one-way ANOVA and Tukeys HSD test). Results: All groups presented remnants of filling material; PTU had the smallest amount and HF group presented the highest mean value (P< 0.05) in all the thirds. The cervical third had the smallest amount of material when compared with the other thirds (P< 0.05). HF group required a longer mean time, presenting significant difference (P< 0.05). Conclusion: Considering the time required and the amount of the filling removal, ProTaper Retreatment were not superior to ProTaper Universal, but both rotary instruments were more effective and less time-consuming than Hedström manual files.

Cone-beam computed tomography in the assessment of periapical lesions in endodontically treated teeth

Objective: This study aimed to evaluate the relationship between the quality of the coronal restoration and the root canal filling on the periapical status of endodontically treated teeth using CBCT. Materials and Methods: CBCT data were obtained from the records of patients who deny any dental treatment in the 2 years prior to the CBCT examination. CBCT images (90 kVp and 7 mA, exposure time of 23 s, and a voxel size of 0.2 mm, with a field of view of 13 cm × 13 cm) of 1011 endodontically treated teeth were observed. A score was given to the quality of the root filling and the quality of the coronal restoration. Statistical Analysis Used: Data were statistically analyzed to correlate the periapical status with gender, dental group. and quality of endodontic treatment and restoration (Chi-square test with a significance level of P < 0.001). Results: Absence of periapical periodontitis was found in 54.9% of the cases. The periapical outcome was not related to gender or dental group (P > 0.05). A statistically significant factor (Chi-square test, P < 0.0001) resulted when different qualities of sealing were compared. Conclusions: CBCT showed that high-quality root canal treatments followed by an adequate coronal sealing restoration avoid the presence of periapical periodontitis in time.

Accuracy of 2 Endodontic Rotary Motors with Integrated Apex Locator

INTRODUCTIONnThe purpose of this study was to evaluate inxa0vitro the efficacy of both the electronic apex locator (EAL) and auto apical reverse (AAR) functions of the endodontic motor MM Control (Micro-Mega, Besançon Cedex, France) compared with Root ZX II (J Morita, Tokyo, Japan).nnnMETHODSnAfter cervical preflaring, the actual lengths (ALs) of 36 single-rooted teeth were obtained up to the apical foramen. The EAL measurements at the marks APEX and 0.5 of both devices were obtained using an alginate model. The teeth were divided randomly into 2 groups (nxa0=xa018), and root canal preparation was performed with rotary instruments using the AAR function (0.5 mark) of each motor. The length provided by the AAR was compared with the visual length after preparation (AL2). The differences between the electronic lengths and the respective visual measurements were assigned as negative for lower or positive when higher. The means of the absolute values and the percentages of distribution of the electronic measurements between devices were compared.nnnRESULTSnThere was no difference between the devices in terms of the means of the EAL measurements or AAR length (analysis of variance, Pxa0>xa0.05). However, the EAL function of MM Control presented a greater percentage of measurements >1.01xa0mm longer than AL (chi-square, Pxa0<xa0.01). The AAR function provided an acceptable apical limit in 83.3% of the cases for Root ZX and 77.8% of the cases for MM Control.nnnCONCLUSIONSnThe AAR function of both MM Control and Root ZX II provided an adequate apical limit of preparation inxa0vitro. However, the use of only the EAL function of MM Control resulted in significantly more cases of overextended readings.

Influence of the Calcium Hydroxide Intracanal Dressing on Dentinal Tubule Penetration of Two Root Canal Sealers

Objective: The aim of this study was to evaluate the effect of a calcium hydroxide (CH) dressing on the tubular penetration of two endodontic sealers, AH Plus (Dentsply Maillefer, Ballaigues, Switzerland) and MTA Fillapex (Angelus, Londrina, Brazil). Methods: Seventy-two mandibular premolars with a single root canal were prepared with ProFile.04 rotary instruments (Dentsply Maillefer) and divided into four groups. In two groups, an intracanal CH dressing was placed for 15 days. The obturations were performed with lateral condensation of gutta-percha in combination with one of the tested sealers. The roots were transversely sectioned at the apical and middle levels. The percentage of sealer penetration in the root canal walls and the percentage of impregnated dentin area in the transverse sections were obtained using confocal laser scanning microscopy. Statistical analysis was performed using one-way analysis of variance (ANOVA) and Games-Howell test. Results: The CH dressing reduced the mean value of tubular penetration in the middle third of teeth obturated with AH Plus (P<0.01), whereas no difference was observed at the apical sections for both sealers. Conclusion: The CH dressing did not interfere with the apical penetration of both tested sealers, however, decreased the tubular penetration in the middle third of the AH Plus root canal fillings. Overall, MTA Fillapex presented higher tubular penetration than AH Plus obturations.