Root Canal Length Research Articles

Coronal preflaring’s influence on the accuracy of root canal length determination by electronic apex locators

Coronal preflaring’s influence on the accuracy of root canal length determination by electronic apex locators

Do the apical limit and diameter of the instrumentation influence the extrusion of sodium hypochlorite solution? A micro-CT study.

This study evaluated the influence of the apical limit and the diameter of the instrumentation on the extrusion of the irrigating solution. Sixty human lower premolars were distributed into 5 groups according to the apical limit and diameter of the root canal instrumentation (n = 12): (G-140) R40 instrument 1mm above the tooth length (TL) (Control); (G-150) R50 instrument 1mm above the TL; (GF25) R25 instrument at the TL; (GF40) R40 instrument at the root canal length and (GF50) R50 instrument at the TL. A space of 33.5 ± 1 mm3 was created for storage of the extruded solution. Omnipaque contrast was added to the NaOCl solution in a 1:2 ratio, totaling 15mL of solution to allow its visualization when extruded in microcomputed tomography. Final irrigation was performed with a syringe and needle and activated with a passive ultrasonic irrigation (PUI). Three activation cycles were performed. Data were tabulated and statistically analyzed (one-way ANOVA) with a significance level set at 5%. It was observed irrigating solution extrusion after final irrigation in all groups. However, there were no statistically significant differences among experimental groups, regardless of the diameter or apical limit of root canal instrumentation (p > 0.05). The different apical limits and diameters of root canal instrumentation did not influence the volume of extruded irrigating solution using passive ultrasonic irrigation.

Procedure for Determining Root Canal Length in Endodontics: A Mathematical Approach

Intraoral and extraoral radiographic investigations play a fundamental role in all dental disciplines. For endodontic treatment it is necessary, in addition to measuring with apex locators, also various radiographs in the preoperative, operative, and final control phase. Even in surgical practice, and especially in implantology, the radiographic investigation remains essential to limit errors or complications. The mathematical approach for the determination of the length of work in endodontics is a simple and costless procedure. This work intends to expose the reasons why it should, in certain cases, be taken into consideration.

Construction and Evaluation of an AI-based CBCT Resolution Optimization Technique for Extracted Teeth

IntroductionIn dental clinical practice, cone-beam computed tomography (CBCT) is commonly used to assist practitioners to recognize the complex morphology of root canal systems; however, because of its resolution limitations, certain small anatomical structures still cannot be accurately recognized on CBCT. The purpose of this study was to perform image super-resolution (SR) processing on CBCT images of extracted human teeth with the help of a deep learning model, and to compare the differences among CBCT, super-resolution computed tomography (SRCT), and micro-computed tomography (Micro-CT) images through three-dimensional reconstruction. MethodsThe deep learning model (Basicvsr++) was selected and modified. The dataset consisted of 171 extracted teeth that met inclusion criteria, with 40 maxillary first molars as the training set and 40 maxillary first molars as well as 91 teeth from other tooth positions as the external test set. The corresponding CBCT, SRCT, and Micro-CT images of each tooth in test sets were reconstructed using Mimics Research 17.0, and the root canal recognition rates in the 3 groups were recorded. The following parameters were measured: volume of hard tissue (V1), volume of pulp chamber and root canal system (V2), length of visible root canals under orifice (VL-X, where X represents the specific root canal), and intersection angle between coronal axis of canal and long axis of tooth (∠X, where X represents the specific root canal). Data were statistically analyzed between CBCT and SRCT images using paired sample t-test and Wilcoxon test analysis, with the measurement from Micro-CT images as the gold standard. ResultsImages from all tested teeth were successfully processed with the SR program. In 4-canal maxillary first molar, identification of MB2 was 72% (18/25) in CBCT group, 92% (23/25) in SRCT group, and 100% (25/25) in Micro-CT group. The difference of hard tissue volume between SRCT and Micro-CT was significantly smaller than that between CBCT and Micro-CT in all tested teeth except 4-canal mandibular first molar (P < .05). Similar results were obtained in volume of pulp chamber and root canal system in all tested teeth (P < .05). As for length of visible root canals under orifice, the difference between SRCT and Micro-CT was significantly smaller than that between CBCT and Micro-CT (P < .05) in most root canals. ConclusionsThe deep learning model developed in this study helps to optimize the root canal morphology of extracted teeth in CBCT. And it may be helpful for the identification of MB2 in the maxillary first molar.

The ability of working length determination of the electronic apex locator Propex Pixi in the presence of various irrigants - an in vitro study

Background: To achive success in endodontic treatment, the clinicians have to completely control the depth of penetration of instruments inside the root canal called the working length. Determining the working length by using electronic apex loactors have been increasingly popular and gradually become an indispensable tool in endodontics. The purposes of this study was to compare the working length determined by Propex Pixi with the actual canal length as well as evaluate the effect of various intracanal irrigants on the accuracy of Propex Pixi. Materials and method: 45 human incisors extracted for periodontal reasons were selected for this in vitro study. Standard access preprations were prepared, then digital Caliper was used to meassure the actual root canal length. Teeth were imbedded in alginate model. The working length was determined by using the Propex Pixi in the presence of different irrigant solutions: distilled water, 2.5% NaOCl and 2% Chlorhexidine. The working length meassurements obtained with Propex Pixi were compaired with the actual root canal length and then evaluating the effect of irrigation solutions on the accuracy of Propex Pixi. Results: There was no significant differences between the actual canal length and the WL determined by Propex Pixi (p &gt; 0.05). Root canal irrigants has no effect on the accuracy of Propex Pixi. Conclusion: There was no significant differences between actual root canal length with the measurements obtained by Propex Pixi. The accuracy of Propex Pixi was not affected by the irrigants used. Key words: working length, electronic apex locator, Propex Pixi.

Ex-vivo Evaluation of the Accuracy of Three Different Apex Locators in the Presence of Sodium Hypochlorite in Root Canals

Objective: To evaluate the precision of three endodontic apex locators-Propex Pixi, Woodpex III, and VDW Gold Reciproc-in vitro and under clinical conditions. Materials and Methods: Thirty-six single-rooted teeth were decoranated, and actual root canal lengths were measured and recorded with an operating microscope at x20 magnification. The teeth were then embedded in an ex-vivo model, and the measurement of the root canal length was obtained electronically. Each measurement was performed in triplicate, and the mean value was recorded. Data were analyzed statistically. Two paired sample t-tests were used for normally distributed data, and the Wilcoxon test was used for data that did not show normal distribution. A chi-squared test was used to compare categorical variables according to the experimental groups. Results: Woodpex III showed significantly more accurate results than the other apex locators. Propex Pixi and VDW Gold Reciproc apex locators showed no significant difference. Conclusions: Under the circumstances of the present study, Woodpex III allowed for more accurate measurements compared with the other tested devices.

Influence of Different Apical Foramen Morphologies on the Accuracy of Four Electronic Foramen Locators.

The aim of this study was to evaluate the accuracy of the Root ZX II (RZX), Raypex 6 (RAY), EPex Pro (EPEX), and CanalPro (CNP) electronic foramen locators (EFLs) in different foraminal morphologies (fully formed foramen, immature foramen with parallel walls, and immature foramen with divergent walls); this article also evaluated the influence of different penetration levels (0.0 mm and -1.0 mm). Thirty single-rooted human premolars were accessed and had their cervical/middle thirds prepared with SX ProTaper files. The apical foramens (AF) were standardized to 250 µm and the initial root canal length (RCL1) was measured under 16x magnification with aid of a digital caliper. Using the alginate model, electronic measurements (EM) were taken 1.0 mm up to AF (EM1/-1) and at AF (EM1/0), always using adjusted hand K-files. The root apexes were then cross-sectioned 3.0 mm from the foramen; then, new RCL (RCL2) and electronic measurements were performed (EM2/-1 and EM2/0.0). Finally, retropreparations were performed with instruments SX ProTaper files introduced 4.0 mm in the apicocervical direction. Then new RCL (RCL3) and electronic measurements (EM3/-1 and EM3/0) were performed. Values were tabulated and tested for normality using the Shapiro-Wilk test, which yielded nonparametric distributions of the data. Data were subjected to the Kruskal-Wallis and Dunn tests to estimate possible differences between devices as a function of foramen morphology and/or apical limit. The significance level was set at 5.0%. In general, the EFLs were accurate in determining the RCL. Statistically significant differences were observed between EPEX and RAY at 0.0, when measuring the divergent AF canals (p < 0.05). Regarding the different foramen morphologies in each EFL, RZX and EPEX showed no interference (p > 0.05), whereas RAY and CNP had lower accuracy levels at 0.0 with divergent AF (p < 0.05). The four devices evaluated are accurate to determine the RCL in the conditions tested. The apical limit of penetration did not have significant influence on their accuracy. Conversely, the presence of divergence in the AF walls negatively influenced de RAY and CNP precisions at the foraminal level.

Accuracy of an Electronic Apex Locator (EAL) in Measuring the Working Length of Root Canals in Comparison WithRadiographs: An In Vivo Study.

Traditionally, radiographs were used to assess the working length of root canals. However, the use of Electronic Apex Locators (EAL) may be a non-invasive alternative. This study aimed to evaluate the accuracy of the electronic apex locator (EAL) compared to radiographic measurements in determining the working length of root canals. The study assessed the performance of EALs in different scenarios, including the presence of blood and pulp tissue, the use of ethylenediaminetetraacetic acid (EDTA), sodium hypochlorite (NaOCl) as an irrigant, and post-instrumentation with normal saline. An electronic apex locator(DTE DPEX-V; Woodpecker, China) was used alongside traditional radiographs to measure the working length in 144 root canal treatments. Bland-Altman analysis was used to compare the measurements between EAL and radiographs using Jamovi software, v2.4.8 (https://www.jamovi.org/). The findings revealed strong correlations between EAL and radiographic measurements across all testing environments, with Pearson's correlation coefficients ranging from 0.944 to 0.998. The Bland-Altman analysis suggests bias; the average difference was negative and close to zero (Pulp: -0.354, EDTA: -0.0972, NaOCl: -0.0382, Saline: -0.0139) when EAL measurements were compared to radiographic measurements. The working length measurement of root canals using an electronic apex locator such as DTE DPEX-V is comparable to traditional radiographic measurements. The use of irrigants improves the measurement. The EAL has the potential to be an alternative to the invasive radiograph for root canal length measurement.

An Ex-Vivo Study Comparing the Accuracy of the E-Connect S+ and Morita Tri Auto ZX2+ Endodontic Handpieces in Root Canal Length Determination

IntroductionThis ex vivo study evaluated the accuracy of the Electronic Apex Locator (EAL) and Automatic Apical Stop (AAS) functions of the E-Connect S+ and Morita Tri Auto ZX2+ cordless apex locators in determining patency length. MethodsSixty-four human teeth with a single root were randomly allocated into E-connect or Morita groups (n = 32). The canals were accessed and preflared, after which a size 15 K-file was inserted into the canal to the major foramen and recorded as the actual length (AL). Matched measurements were taken using the AAS and EAL functions and visually confirmed with confocal microscopy. The variance between canal length (mm), the persons correlation (ρ) between function and AL, and the accuracy (%) of the canal length relative to the AL (Δmm) between devices and functions were assessed. ResultsRegardless of device or function, all measurements were within 1±Δmm and correlated strongly (ρ > 0.97) with the AL. When considering a more stringent clinically acceptable range of 0.5±Δmm from the AL, all devices and functions demonstrated similar accuracy levels (84%–94%). However, at lower tolerance ranges, the E-connect device with the EAL function exhibited the highest accuracy. On average, all devices and functions stopped short of the AL (mean Δmm>0). ConclusionThe E-Connect S+ and Morita Tri Auto ZX2+ apex locators provided reliable accuracy in determining the position of the major foramen. These findings demonstrate a high level of reproducibility in canal length measurements using both cordless endodontic handpieces, regardless of whether the EAL or AAS functions were employed.

Evaluation of the Accuracy in Four Electronic Apex Locators toward determination of working length of root canal: an in-vitro study

Evaluation of the Accuracy in Four Electronic Apex Locators toward determination of working length of root canal: an in-vitro study

Ex vivo evaluation of the accuracy of four electronic foraminal locators during endodontic retreatment.

The present study aimed to evaluate the accuracy of four different Electronic Foraminal Locators (EFLs): Root ZX II (J. Morita, Tokyo, Japan), RomiApex A15 (Romidan, Kiryat-Ono, Israel), FinePex (Schuster, Porto Alegre, Brazil) and VDW Gold (VDW, Munich, Germany), in determining root length during endodontic retreatment steps. Twenty-seven human unirooted teeth had their crowns sectioned to standardize the teeth to 17 mm. The actual tooth length was visualized with an operating microscope and a #15 file juxtaposed to the apical foramen. Teeth were instrumented with files R25 and R40, and at the end of each instrumentation, measurements of root canal lengths were made with files #25 and #40. Then, the teeth had their root canals filled with standardized Gutta-Percha R40 cones and Endofill cement, and after seven days, they were uncovered with R25 and R40 files, respectively. New measurements were made with #25 and #40 files between the uncovering with each file. The data were statistically analyzed by ANOVA and Chi-square tests, considered significant when P<0.05. All devices tended to under-measurement when the obturating material was partially removed with the R25 file. When the canals were uncovered with the R40 instrument, the effectiveness of the appliances increased significantly (P<0.05). At 0.40 mm diameter, the mean accuracy of the Romiapex A15 appliance was statistically lower than the other EFLs (P<0.001), showing a tendency to over-measurement. In conclusion, all the tested appliances showed similar efficacy when acceptable limits were observed. The permanence of the remaining filling material in the apical third influenced the accuracy and efficacy of EFLs in endodontic retreatment cases. Key words:Endodontics, odontometry, apical foramen.

Accuracy of an Endodontic Rotary Motor with Integrated Apex Locator to Determine the Root Canal Length

Aim: The purpose of this study was to evaluate the efficacy to determine the root canal length, in vitro, of both the electronic apex locator (M2) and the autostop (AS - M3) functions of the Endus Duo Gnatus endodontic motor (Gnatus, São Paulo, SP, Brazil). Methods: Thirty extracted human single-rooted premolars had their root canal lengths (TLs) up to the apical foramen determined using the Endus Duo Gnatus in two ways: (1) In the stainless steel (SS) control group, the measurement was obtained using a stainless steel hand instrument with the electronic locator mode (M2 function) connected to a stainless-steel hand instrument (K-file #15). In the NiTi rotary instrument (NiTi RI) intervention group, the measurement was obtained during the instrumentation (M3 function) of the root canals with a nickel-titanium rotary instrument (Hyflex CM: Coltene Whaledent, Cuyahoga Falls, OH, USA), size 25/.06. The NiTi manually used instrument (NiTi MUI) Intervention group performed the measurement in locator mode using a Hyflex instrument, placed to true length manually. Statistical analysis was performed using ANOVA followed by the Tukey post-hoc test with a significance level of p &lt; 0.05. Results: The true mean length and standard deviation (SD) of the standardized root canals were 18.40 ± 2.14mm, while the mean lengths and standard deviations (SD) were 18.29 ± 1.89mm, 18.22 ± 1.85mm, and 17.24 ± 2.09mm for the SS, NiTi RI, and NiTi MUI groups, respectively. However, data from the NiTi MUI Intervention group indicated shorter root canal lengths when compared to the SS control group and the NiTi RI Intervention group values, and were significantly shorter than the true canal length (p &lt; 0.001). Conclusions: The use of the motor in NiTi RI Intervention group showed acceptable results. However, the NiTi MUI Intervention group resulted in unacceptable short measurements.

Breaking the error chain with SEE: cascade analysis of endodontic errors in clinical training

ABSTRACT The ongoing endeavors to uncover the link between the prevalent errors in clinical endodontic training and undergraduate education are founded on tentative assumptions. This investigation was aimed at determining if cascade analysis can provide an understanding of the origins and causes of errors and if the sensitivity of student reports to the impact of errors on treatment outcomes can be established.In 2021, a group of investigators from the endodontics department concerned with clinical dental education launched the Study of Endodontic Errors (SEE). Sixty-six undergraduate dental students at one dental teaching hospital submitted anonymous narratives of problems they witnessed in their root canal treatment practices. The reports were examined to determine the sequence of events and the major errors. We kept track of the consequences of treatment outcomes, both as reported by students and as deduced by investigators.In 77% of the narratives, a chain of errors was recorded. The majority of the errors that took place were related to the working length or width of root canals. A substantial portion, 86%, of these errors could have been prevented through a deeper comprehension of the concepts that underlie working length and width. 75% of the errors that initiated cascades involved losing the correct working length. When asked whether the treatment outcome was compromised, students answered affirmatively in 16% of cases in which their narratives described compromised outcomes. Unacceptable outcomes necessitating re-treatment accounted for only 3% of student-reported consequences, but when investigator-inferred consequences were considered, the percentage more than doubled (7%).Cascade analysis of student error narratives is useful in understanding the triggering chain of events, but students provide insufficient information about how treatment outcomes are affected. Misconceptions about working length and width appear to play a significant role in the propagation of procedural errors.

Evaluation the Marginal Adaptation for the Bio C Repair and Other Root end Filling Material by Using Scanning Electron Microscope (A Comparative In Vitro Study)

АBSTRАCT:‏‏‏‏‏‏ Background: The ability of the retrograde filling material to adhere to dentin has a substantial impact on the success of endodontic procedures. the marginal adaptation of the rᴏᴏt end filling materials considered important factor, since it demonstrates the materials adaptation to the dentinal walls. Objective: Assess the marginal adaptation of Biᴏ-C reparative materials in contrast to MTA (АNGELUS) and Amalgam. Material and method: A total of thirty human maxillary central incisors teeth that each had a single root were chosen. To keep the root canal length at 15mm, the crown was resected. The teeth underwent endodontic treatment, along with the resection of their root ends and preparation of root-end cavities. On the basis of the type of filling, the teeth were categorized into one of three groups, as follows: (А) Bio-C repair (Bioceramic reparative material), (B) MTА АNGELUS, (C) Amalgam. teeth were sectioned in longitudinal manner, marginal gabs measured by the use of a scanning electron microscope. Data was statically analyzed using АNOVА and Tukey Honestly Significant Difference (Tukey's HSD). Results: Bio-C Repair material and MTA show better marginal adaptation with significant difference between them and amalgam, no significant different between Bio-C repair group and MTA group. Conclusion: marginal adaptation better for Bio-C repair in comparison to Amalgam and MTА АNGELUS

Evaluation of changes in root canal length and accuracy of the electronic apex locator during different stages of endodontic treatment and retreatment.

This study evaluated changes in the root canal length (RCL) and the accuracy of the electronic apex locator (EAL) during the different stages of endodontic treatment and retreatment. Fifty-six mesial root canals of mandibular molars were selected. The actual root canal length (AL) of the canals was obtained by inserting a size 15 hand file up to the apical foramen, under magnification. The electronic lengths were obtained at the "APEX" mark of Root ZX II, using an alginate model. Both measurements were performed at three different stages of the initial root canal treatment-unflared, flared, and concluded-and at two stages of retreatment, after achieving patency and repreparation. Data were statistically analyzed and the significance level established was 5%. All stages produced a significant reduction in the AL (p < 0.05). The greatest variation was observed between the unflared-flared stages (0.2mm) and between concluded-patency stages (0.09mm), with no difference between them (p > 0.05). The accuracy of Root ZX II was negatively affected after achieving patency, presenting statistically significant difference compared to the other stages (p < 0.05). A significant reduction in the RCL was observed along the different stages of endodontic treatment and retreatment. The EAL was accurate to measure the root canals in most stages, except after achieving patency for endodontic retreatment. Determining and monitoring the RCL is an essential step towards a favorable prognosis, since it reduced along the different stages evaluated. Root ZX II was not accurate for endodontic retreatment.

Evaluation of The Accuracy of Two Apex Locators For Determining The Working Length of Endodontically Retreated Curved Mesial Roots of Maxillary Molar Teeth : An Ex Vivo Study

Objective: To evaluate the accuracy of PROPEX PİXİ (Dentsply Sirona, Ballaigues, Switzerland) and Apex ID (Sybron Endo, Orange, CA, USA) in determining the working lengths of curved mesial roots of upper molars during the retreatment procedure. Method: Twenty curved mesial roots of upper molar teeth were selected. Canals were shaped with ProTaper Next instruments (Dentsply Sirona) up to X3. The canal lengths were determined with a microscope (Carl Zeiss GmbH, Oberkochen, Germany) at 2,5X magnification (DM) and then also detected electronically (EM1P and EM1A) with PROPEX PİXİ (Dentsply Sirona) and Apex ID (Sybron Endo) in an alginate model. Specimens were then obturated using a size X3 master gutta-percha cone and an epoxy resin-based root canal sealer. Seven days later, the coronal part of the filling was removed with a Gates Glidden drill size 3 and for the middle part Protaper Universal Retreatment File D2 used. Working lengths electronically were detected again by two different apex locaters (EM2P and EM2A). Data were analysed by using the Wilcoxon Signed Rank and Mann Whitney u test. The analyses were carried out with MedCalc Statistical Software. Results: No significant difference was found between direct measurements (DM) and electronic measurements before and during retreatment for PROPEX PİXİ (P=0.135) and Apex ID (P=0.232). Also there was no significant difference between two apex locaters before (P=0.108) and during retreatment (P=0.242) Conclusion: PROPEX PİXİ and Apex ID were considered accurate for the root canal length determination during retreatment procedure. Keywords: Apex locator, curved molar, retreatment, working lenght

Study of Root Canal Length Estimations by 3D Spatial Reproduction with Stereoscopic Vision

Extended Reality (XR) applications are considered useful for skill acquisition in dental education. In this study, we examined the functionality and usefulness of an application called “SR View for Endo” that measures root canal length using a Spatial Reality Display (SRD) capable of naked-eye stereoscopic viewing. Three-dimensional computer graphics (3DCG) data of dental models were obtained and output to both the SRD and conventional 2D display devices. Forty dentists working at the Kanagawa Dental University Hospital measured root canal length using both types of devices and provided feedback through a questionnaire. Statistical analysis using one-way analysis of variance evaluated the measurement values and time, while multivariate analysis assessed the relationship between questionnaire responses and measurement time. There was no significant difference in the measurement values between the 2D device and SRD, but there was a significant difference in measurement time. Furthermore, a negative correlation was observed between the frequency of device usage and the extended measurement time of the 2D device. Measurements using the SRD demonstrated higher accuracy and shorter measurement times compared to the 2D device, increasing expectations for clinical practice in dental education and clinical education for clinical applications. However, a certain percentage of participants experienced symptoms resembling motion sickness associated with virtual reality (VR).

In Vitro Evaluation of the Accuracy of Three Electronic Apex Locators Using Different Sodium Hypochlorite Concentrations.

Background and Objectives: The aim of this study was to compare the accuracy of three types of electronic apex locators (EALs) when two different concentrations of NaOCl irrigation solutions are used by two operators. Materials and Methods: After creating the access cavities for 20 single rooted extracted teeth, the actual canal length (ACL) of each canal was determined visually using a #10 file and magnification. The teeth were subsequently inserted in plastic molds filled with alginate. The electronic measurement of root canal length (EWL) was performed using three different electronic apex locators: Root ZX II, Apex ID, and Dual Pex. Two independent operators, an endodontic specialist with 20 years practice and an undergraduate student in the final year of study, performed the irrigation procedures with two different concentrations of NaOCl (2% and 5.25%), and then measured the EWL using each of the EALs. The accuracy of all EALs, was determined in each case by subtracting the EWL from the ACL. Statistical analyses were performed using one-way ANOVA test. Results: In the presence of 2% NaOCl solution, for a margin error of ±0.5 mm, Root ZX II, Apex ID, and Dual Pex presented an accuracy of 90%, 80%, and 85% respectively. The increase in the concentration of the irrigation solution affected the accuracy of Root ZX II and Apex ID for both operators, diminishing it to 75% for the same margin error, but improved Dual Pex's accuracy to 100%. Conclusions: The best accuracy in working length determination was obtained by Root ZX II for 2% NaOCl solution and by Dual Pex for 5.25% NaOCl solution with no significant statistical difference when compared.

Comparative SEM study of the marginal adaptation of MTA and Biodentine after apical resection (in vitro study)

Successful periapical surgery requires appropriate root resection, preparation, and adequate sealing. The aim of the present study was to assess the marginal adaptation of MTA and Biodentine after apical resection with an Er:YAG laser and a diamond turbine bur using a scanning electron microscope (SEM). The crown part of forty-eight extracted single-root human teeth was removed, and the root canal length of 15mm was standardized. The root canals were prepared using rotary Ni-Ti Revo-S files up to an apical stop - AS40 and filled with MTA Fillapex and gutta-percha points (cold lateral condensation). The teeth are divided into 2 main groups: group 1 (n=24) after apical resection with a turbine bur, ultrasonic preparation of the retrograde cavity at 3mm depth and retrograde obturation with Biodentine and MTA; group 2 (n=24) after apical resection with an Er:YAG laser, ultrasonic preparation of the retrograde cavity at a depth of 3mm and retrograde obturation with MTA and Biodentine. A SEM was used for assessment of the marginal adaptation of the material to the root dentin. The data was entered into and analyzed with IBM SPSS Statistics 22.0. In the group with apical resection with a turbine bur, a statistically significant difference in the gap size between the material and dentin was found in both materials we studied (MTA and Biodentine). The higher mean value was in MTA (1.72µm), in Biodentine it was 1.08µm. In the group with apical resection with Er:YAG laser, no statistically significant difference in the gap size between the material and dentin was found in both studied materials: MTA - 1.88µm, Biodentine - 1.32µm. In the present study, MTA and Biodentine showed good sealing capabilities after apical resection. Biodentine displayed better marginal adaptation when resecting the root tip using a turbine bur. The Er:YAG laser-assisted apical resection shows sealing of the open dentinal tubules around the resected root surface.

Prediction of root canal lengths and pulp volume of the maxillary permanent first molar based on stature, crown diameters, and facial morphometry.

This study purposed to develop statistical models to predict palatal (PRL), mesial (MRL), and distal (DRL) root canal length and pulp volume (PV) of the maxillary first permanent molar using stature, gender, mesiodistal (MD), and buccopalatal (BP) crown diameters and some facial morphometries. 57 individuals were included in the study. Cone beam computed tomography was used to measure root canal lengths and PV. The PV calculation was carried out using the software ITK-SNAP 3.4.0. PRL was positively correlated with BP, stature, middle facial height, interalar distance, and bicommissural distance (BCD) (p < 0.05). DRL was positively correlated with BP, MD, and stature (p < 0.05). MRL was positively correlated with BP, MD, stature, lower face height, bizygomatic distance, and BCD (p < 0.05). PV was negatively correlated with age and BCD (p < 0.05). Although all models have significant predictive power for the root lengths and PV, no model could explain variances greater than 30%. The highest and lowest predictive ability was obtained for PRL and DRL, respectively. While the most significant predictor was BP for PRL and DRL, it was the age for PV.