Anatomic Apex Research Articles

Morphology of apical foramen in permanent molars and premolars in a Turkish population

Objective: To determine the number, shape and diameter of minor apical foramina, the distance between apical foramina and anatomical apex and the frequency of accessory foramina in a Turkish population. Materials and methods: Eight hundred permanent maxillary and mandibular teeth were collected. The roots were stained with methylene blue and the apices were examined with a stereomicroscope (×40) and transferred to a computer to perform the measurements using Adobe Photoshop software. Results: The incidence of one apical foramen was highest in distobuccal roots of the maxillary first molars and was lowest in the maxillary first premolars with single roots. The distance of deviation in all the teeth was between 0.271–0.519 mm. The frequency of accessory foramina was between 30–70% for the various tooth types. Conclusions: The results of this in vitro study indicate that the morphology of apical foramina in this Turkish population may present highly complex anatomical variations.

Incidence of Apical Root Cracks and Apical Dentinal Detachments after Canal Preparation with Hand and Rotary Files at Different Instrumentation Lengths

IntroductionThe aim of this study was to compare the incidence of apical root cracks and dentinal detachments after canal preparation with hand and rotary files at different instrumentation lengths. MethodsTwo hundred forty mandibular incisors were mounted in resin blocks with simulated periodontal ligaments, and the apex was exposed. The root canals were instrumented with rotary and hand files, namely K3, ProTaper, and nickel-titanium Flex K files to the major apical foramen (AF), short AF, or beyond AF. Digital images of the apical surface of every tooth were taken during the apical enlargement at each file change. Development of dentinal defects was determined by comparing these images with the baseline image. Multinomial logistic regression test was performed to identify influencing factors. ResultsApical crack developed in 1 of 80 teeth (1.3%) with hand files and 31 of 160 teeth (19.4%) with rotary files. Apical dentinal detachment developed in 2 of 80 teeth (2.5%) with hand files and 35 of 160 teeth (21.9%) with rotary files. Instrumentation with rotary files terminated 2 mm short of AF and did not cause any cracks. Significantly less cracks and detachments occurred when instrumentation with rotary files was terminated short of AF, as compared with that terminated at or beyond AF (P < .05). The AF deviated from the anatomic apex in 128 of 240 teeth (53%). Significantly more apical dentinal detachments appeared in teeth with a deviated AF (P = .033). ConclusionsRotary instruments caused more dentinal defects than hand instruments; instrumentation short of AF reduced the risk of dentinal defects.

Canal and Isthmus Debridement Efficacy of the VPro EndoSafe Negative-pressure Irrigation Technique

IntroductionThis study compared canal and isthmus debridement efficacies between side-vented needle irrigation (SNI) and the VPro EndoSafe (VPro) negative-pressure device (Vista Dental, Racine, WI) in mesial roots of mandibular first molars with narrow isthmuses in a closed-canal design. MethodsTwenty teeth with narrow isthmuses were selected using micro–computed tomography scanning. Collagen solution was reconstituted with 1% NH4OH to simulate debris and injected into canals via vacuum. Canals were instrumented to size 40/.04. Final irrigation was performed with 17% EDTA and 6% NaOCl using SNI with a 30-G needle or the VPro system. Roots were demineralized, and Masson trichrome–stained sections were prepared at 1.2 to 3.2 mm from the anatomic apex for a total of 6 canal levels. Debris-filled areas within the canals and isthmuses were measured using ImageJ software (National Institutes of Health, Bethesda, MD) and statistically analyzed using repeated-measures analysis. ResultsThere was no significant difference between techniques and debridement efficacy among the 6 levels within the canal (P = .108). The debridement efficacy at 1.6 mm differed significantly from that at 3.2 mm. VPro had significantly more debris at isthmus levels 2.0 and 2.4 mm than SNI (P = .009). A significant difference was observed between the canal and the isthmus (P < .001). Neither VPro nor SNI removed debris completely from the apical third or isthmus. ConclusionsVPro EndoSafe did not differ significantly from SNI in the overall debridement efficacy in the apical third of mesial roots of mandibular first molars.

Microcomputed tomography analysis of mesiobuccal orifices and major apical foramen in first maxillary molars.

Objective:Aim of the study was to determined by microcomputed tomography (µCT) the horizontal distance between the main (MB1) and the second mesiobuccal canal (MB2) orifices, the vertical distance between the MB1 and MB2 orifices planes, and the distance between the anatomic apex and major apical foramen (AF). Furthermore, we characterized the entire internal and external anatomy of the MB, distalbuccal (DB) and palatal (P) maxillary first molars roots.Materials and Methods: Twenty-two intact extracted first maxillary molars were scanned by X-ray computed transaxial µCT and then 2D and 3D images were processed and analyzed.Results:The results showed that 77.27% of the mesiobuccal (MB) roots presented a second MB canal, and 29.41% of the MB2 were independent from the MB1 canals. In 15 teeth, there were three root canal orifices on the chamber floor, and 10 of these teeth presented MB2 canals. The mean vertical distance between the MB1 and MB2 planes was 1.68 ± 0.83 mm. Seven teeth had four orifices. The mean horizontal interorificial distance between the MB1 and MB2 orifices was 1.21 ± 0.5 mm. Accessory canals were observed in 33.33% of the roots, loops in 6.06%, while isthmuses were found in 15 of the 22 MB roots. Of the total roots, 74.24% presented one foramen, while all of the roots showed a major apical foramen that was not coincident with the anatomic apex. Conclusions:Our µCT analysis provided interesting features on the horizontal and vertical distance between the MB1 and MB2 orifices and on the distance of AF and anatomic apex.Clinical Relevance:These results have an important clinical value because might support the endodontist in the recruitment, negotiation and obturation of maxillary first molar canal system.

Canal and Isthmus Debridement Efficacy Using a Sonic Irrigation Technique in a Closed-canal System

IntroductionThis in vitro study compared debridement efficacies of a sonic irrigation technique (Vibringe; Cavex Holland BV, Haarlem, The Netherlands) with side-vented needle irrigation (SNI) in the mesiobuccal root of maxillary first molars. MethodsTwenty roots with narrow isthmuses (≤1/4 canal diameter) were selected using micro–computed tomography scanning. Collagen solution was injected into canals/isthmuses and reconstituted with NH4OH to simulate canal debris. Each root was sealed apically and embedded in polyvinyl siloxane simulating a closed-canal system. Canals were instrumented to size 40/.04 taper 1 mm short of the anatomic apex. The final irrigation was performed with the Vibringe or SNI. Roots were demineralized, sectioned at 6 levels (1.2–3.2 mm) from the anatomic apex, and stained using Masson trichrome stain. The areas occupied by canals and isthmus and the debris-containing areas were statistically analyzed with repeated-measures analyses using “irrigation technique” as the between factor and “canal level” as the within factor (α = 0.05). ResultsCanals had significantly more debris at 1.2 and 1.6 mm (P < .001), but there was no overall difference between the 2 techniques (P = .561). Significant differences were found between the Vibringe and SNI at 2.4, 2.8, and 3.2 mm (P < .05). There was no significant difference in the remaining debris in the isthmus for SNI at all (P > .05). Considerably more debris remained at 1.2 and 2.0 mm for the Vibringe (P < .05). A significant difference was observed between the canal and the isthmus (P < .001). ConclusionsThere is no difference between the Vibringe and SNI in their overall debridement efficacy in apical one third of the mesiobuccal root of maxillary first molars.

Assessing apical transportation in curved canals: comparison between cross-sections and micro-computed tomography

The aim of this study was to compare two methods of assessing apical transportation in curved canals after rotary instrumentation, namely, cross-sections and micro-computed tomography (µCT). Thirty mandibular molars were divided into two groups and prepared according to the requirements of each method. In G1 (cross-sections), teeth were embedded in resin blocks and sectioned at 2.0, 3.5, and 5.0 mm from the anatomic apex. Pre- and postoperative sections were photographed and analyzed. In G2 (µCT), teeth were embedded in a rubber-base impression material and scanned before and after instrumentation. Mesiobuccal canals were instrumented with the Twisted File (TF) system (SybronEndo, Orange, USA), and mesiolingual canals, with the EndoSequence (ES) system (Brasseler, Savannah, USA). Images were reconstructed, and sections corresponding to distances 2.0, 3.5, and 5.0 mm from the anatomic apex were selected for comparison. Data were analyzed using Mann-Whitney's test at a 5% significance level. The TF and ES instruments produced little deviation from the root canal center, with no statistical difference between them (P > 0.05). The canal transportation results were significantly lower (0.056 mm) in G2 than in G1 (0.089 mm) (p = 0.0012). The µCT method was superior to the cross-section method, especially in view of its ability to preserve specimens and provide results that are more closely related to clinical situations.

Accuracy of Root ZX in teeth with simulated root perforation in the presence of gel or liquid type endodontic irrigant

ObjectivesTo evaluate the accuracy of the Root ZX in teeth with simulated root perforation in the presence of gel or liquid type endodontic irrigants, such as saline, 5.25% sodium hypochlorite (NaOCl), 2% chlorhexidine liquid, 2% chlorhexidine gel, and RC-Prep, and also to determine the electrical conductivities of these endodontic irrigants.Materials and MethodsA root perforation was simulated on twenty freshly extracted teeth by means of a small perforation made on the proximal surface of the root at 4 mm from the anatomic apex. Root ZX was used to locate root perforation and measure the electronic working lengths. The results obtained were compared with the actual working length (AWL) and the actual location of perforations (AP), allowing tolerances of 0.5 or 1.0 mm. Measurements within these limits were considered as acceptable. Chi-square test or the Fisher's exact test was used to evaluate significance. Electrical conductivities of each irrigant were also measured with an electrical conductivity tester.ResultsThe accuracies of the Root ZX in perforated teeth were significantly different between liquid types (saline, NaOCl) and gel types (chlorhexidine gel, RC-Prep). The accuracies of electronic working lengths in perforated teeth were higher in gel types than in liquid types. The accuracy in locating root perforation was higher in liquid types than gel types. 5.25% NaOCl had the highest electrical conductivity, whereas 2% chlorhexidine gel and RC-Prep gel had the lowest electrical conductivities among the five irrigants.ConclusionsDifferent canal irrigants with different electrical conductivities may affect the accuracy of the Root ZX in perforated teeth.

The Evaluation of Three Electronic Apex Locators in Teeth with Simulated Horizontal Oblique Root Fractures

ABSTRACT Aim The accuracy of three electronic apex locators (EALs) to locate the apical limit in teeth with simulated horizontal oblique root fractures was investigated. Material and Methods A horizontal oblique incomplete root fracture was simulated on 30 freshly extracted maxillary anterior teeth by means of a notch made on the vestibular root plane 8 mm from the anatomic apex. The EALs investigated were the ProPex II (Dentsply Maillefer, Ballaigues, Switzerland), the Mini Apex Locator (Sybron Endo, Orange CA), and the Dentaport ZX (J. Morita Corp, Kyoto, Japan). The electronic measurements were compared with the real “working length.” Results The accuracy obtained was Dentaport ZX in 66.66% (n=20), the Mini Apex Locator in 63.33% (n=4) and the Propex II in 53.34% (n=4). The analysis of variance and chi-square test showed no statistical significant differences between Propex and Dentaport ZX EALs (Elecronic Apex Locators) at 0.5 mm and 1.0 mm tolerance levels. These results suggest that electronic apex locators can effectively and reproducibly detect oblique root fractures. Conclusion Although Propex II apex locator was not able to determine the working length accurately, but Dentaport ZX and Mini Apex Locator were able to determine the working length within acceptable range.

Microscopic computerized tomographic evaluation of root canal transportation prepared with twisted or ground nickel-titanium rotary instruments

The aim of this study was to evaluate, ex vivo, canal transportation and the centering ability of nickel-titanium rotary instruments manufactured by twisting and by traditional grinding, with the use of microscopic computerized tomography (μCT). Fifteen mandibular molars were embedded in a rubber-based impression material and submitted to μCT before and after instrumentation. Images were reconstructed, and cross-sections corresponding to distances 1, 2, 3, 4, 5, 6, and 7 mm from the anatomic apex were selected for analysis. Statistical analysis was performed with Mann-Whitney test. Canal transportation and centering ability results were similar for both instruments. Statistically significant differences (P < .05) were observed only at the 3 and 4 mm cross-sections, with lower levels of apical transportation and a better centering ratio associated with twisted instruments than with ground instruments. Our findings showed that twisted and ground instruments behaved similarly, allowing the preparation of curved canals with little transportation, which occurred in both mesial and distal directions.

The Apical File Size according to the Root Canal System of Premolars with Single Root

Purpose: To investigate the discrepancies between the apical root canal diameter and initial apical file according to the shape of apical foramen. Materials and Methods: Sixty extracted premolars were assigned to three groups according to the root canal system (type 1, 2, 3) of 20 teeth each. After chamber opening, the initial apical file (IAF) was inserted into root canal until the file tip was just visible through apical foramen under the microscope and fixed with methaacrylate in the root canal. The root tip was cut horizontally 1 mm from the anatomical apex and the apical cross-section was visualized using microscope at ×50 magnification. Results: 1. Mean diameter of IAF was 0.36 mm in type 1, 0.34 mm in type 2, and 0.29 mm in type 3. There were no significant differences among groups. 2. The ratio between the area of apical root canal and IAF was 40.05% in type 1, 27.05% in type 2, and 34.63% in type 3. There was a significant difference between group 1 and 2 (p<0.05). Conclusion: The IAF of premolar was more than size 30 regardless the root canal system, and it was much smaller than real apical canal size in view of the ratio between the area of apical root canal and IAF.

Histologic Evaluation of Canal and Isthmus Debridement Efficacies of Two Different Irrigant Delivery Techniques in a Closed System

Introduction This study compared canal and isthmus debridement efficacies between side-vented needle irrigation (SNI) and continuous ultrasonic irrigation (CUI) in the mesial root of mandibular first molars with narrow isthmuses using a closed-canal design. Methods Micro–computed tomography scanning was used to select 20 teeth, each containing a narrow isthmus. Each root was sealed at the apex; embedded in polyvinylsiloxane to simulate a closed-canal system; and instrumented to size 40, 0.04 taper. Final irrigation was performed with either SNI or CUI ( N = 10). Masson trichrome-stained sections were prepared from demineralized roots at 10 canal levels between 1.0 and 2.8 mm from the anatomic apex. The areas and debris occupied by the canals and isthmus were measured using ImageJ software (National Institutes of Health, Bethesda, MD) and statistically analyzed using repeated-measures analysis. Results Overall, a significant difference was identified between SNI and CUI in the amount of debris remaining in the isthmus ( P = .006) but not in the canal ( P = .940). There was significantly more debris in the most apical three canal levels (1.0–1.4 mm) regardless of the irrigation technique ( P < .001). The isthmus harbored significantly less debris in the CUI group between isthmus levels 1.0 to 2.2 mm when compared with SNI ( P < .001 and P = .029). Neither technique removes debris completely from the canal or isthmuses. Conclusions Compared with SNI, CUI removes significantly more debris from narrow isthmuses of mandibular mesial roots.

Increases of intracanal and root surface temperatures during the obturation of canal using the E&Q master system and the system

Objectives: The purpose of our study is to assess the increases of intracanal and root surface temperatures during the obturation of canal system using the E&Q Master System and the System B. Materials and methods: A split-tooth model was built. To measure the temperature, 6 grooves for the placement of thermocouples were made in the buccal half of the model. On the mesial side, three grooves were made at 2, 4 and 6 mm from the anatomical apex and were extended to the root surface, while on the distal side three grooves were made at 2, 4 and 6 mm up to the intracanal portion. In each of these grooves was inserted a type T thermocouple (Copper-Costantana) with a diameter of 0.076 mm. 40 canal obturations were done: 20 using the E&Q Master System and 20 using the System B, set at 250 °C, both with plugger FM increased to 3.5 mm from WL. The temperatures were recorded at 1 s intervals for a period of 200 s. Results: During the continuous wave obturation technique two peaks in temperature occurred, the first caused by the plugger in the canal, the second during the separation phase. In the E&Q Master System the highest increases were recorded in the thermocouple N.6, which reported average increases of 6.30 °C, while the lowest were recorded in the thermocouple N.1, which reported a value of 2.11 °C. In the System B group the highest increases were recorded in the thermocouple N.6, which reported average increases of 2.80 °C, while the lowest were recorded in the thermocouple N.1, which reported a value of 0.4 °C. Conclusions: Analysis of the obtained results showed that both systems allow us to get a good thermal mass increase of gutta-percha. Results show that the use of E&Q Master System and System B, in vitro , appears to cause a dangerous increase in temperature along the surface of the root that may create iatrogenic injury.

The morphology of the apical foramen in posterior teeth in a North Indian population

To determine the position and shape of the apical foramina in posterior teeth derived from an Indian population. A total of 800 freshly extracted maxillary and mandibular premolar and molar teeth from a native Haryana population were collected. Apices of teeth were stained with methylene blue and then examined stereomicroscopically (40x). The following observations were made: number of apical foramina; size and shape of the minor apical foramen; accessory foramina frequency, and deviation of the minor apical foramina (frequency and distance) from the apex. The mean maximum and minimum diameter of the minor apical foramina ranged from 0.158 to 0.323 mm. The most common minor apical foramen shape was oval (81%). Frequency of accessory foramina was between 2% and 41% for the various tooth types. The frequency of deviation of the minor apical foramina from the anatomic apex varied from 43% to 83% and the distance of deviation in all the teeth was between 0.052 and 2.921 mm. The incidence of oval canals was higher in this Indian population compared to other populations. In 92% and 96% of teeth the difference between the maximum and the minimum diameter of all foramina was less than or equal to 0.20 and 0.25 mm, respectively. Therefore, four to five instrument sizes larger than the first binding file would have been necessary to shape the minor apical foramen of more than 95% of the teeth included in this study to make them round.

Topographical evaluation of the major apical foramen in permanent human teeth

To determine the distance from the anatomical root apex to the major apical foramen and the position of the major foramen on the root apex. Crowns of 926 human teeth were sectioned at the cementum-enamel junction. Specimens were mounted on microscope slides for measurement parallel to the long axis of the teeth. The major foramen was identified as the largest-diameter opening at the root apex. A total of 1331 root specimens were evaluated using an optical stereomicroscope to an accuracy of 0.01 mm at 40 x (+/-10) magnification. The distance from the anatomical apex to the most apical point of the major foramen was measured, and its location (central, buccal, lingual, mesial and distal) was recorded. The mean distance between the major foramen and the anatomical root apex was 0.69 mm; the mean distance was larger in posterior teeth (0.82 mm) and smaller in anterior teeth (0.39 mm). A wide range of anatomical apex to major foramen distances were observed in all tooth groups: the greatest distance was in maxillary molars (0.95 mm) followed by mandibular pre-molars (0.87 mm) and mandibular molars (0.80 mm). The major foramen was at the tip of the root in 40% of teeth. The most frequent deviations of the foramen were to the buccal (20%) and distal (14%). In this sample of teeth without apical resorption the distance between the major foramen and the anatomical root apex was always <1 mm. Deviation of the major foramen from the anatomic apex varied widely amongst tooth groups.

The Evaluation of Four Electronic Apex Locators in Teeth with Simulated Horizontal Oblique Root Fractures

The accuracy of four electronic apex locators (EALs) to locate the apical limit in teeth with simulated horizontal oblique root fractures was investigated. A horizontal oblique incomplete root fracture was simulated on 20 freshly extracted maxillary anterior teeth by means of a notch made on the vestibular root plane 8 mm from the anatomic apex. The EALs investigated were the ProPex (Dentsply Maillefer, Ballaigues, Switzerland), the NovApex (Forum Technologies, Rishon Le-Zion, Israel), the Root ZX (J. Morita Corp, Kyoto, Japan), and the Elements Apex Locator (SybronEndo, Orange CA). The electronic measurements were compared with the real “working length.” The accuracy obtained was of 80% ( n = 16) and 95% ( n = 19) with the ProPex, 70% ( n = 14) and 95% ( n = 19) with the NovApex, 60% ( n = 12) and 90% ( n = 18) with the Root ZX, and 60% ( n = 12) and 85% ( n = 17) with the Elements Apex Locator when tolerances of 0.5-mm and 1.0-mm tolerance were, respectively, allowed. The analysis of variance (p > 0.05) and chi-square test (0.5 mm/p = 0.47 and 1.0 mm/p = 0.63 tolerances) showed no statistical significant differences between the EALs at either tolerance level.

Root Canal Systems in Mandibular First Premolars with C-shaped Root Configurations. Part I: Microcomputed Tomography Mapping of the Radicular Groove and Associated Root Canal Cross-sections

The purpose of this study was to investigate the morphology of the radicular grooves and root canal cross-sections in mandibular first premolars that exhibit a C-shaped root. Eighty-six mandibular first premolars with C-shaped roots were scanned from the coronal to anatomical apex using μCT80. The location, length, and depth of the radicular grooves were measured. The cross-sectional morphology of root canal systems was evaluated at 11 levels. Results were subject to the Kruskal-Wallis test. Of the 86 C-shaped roots, a total of 93 radicular grooves were noted. Most of the grooves (78.5%) were located on the mesiolingual surface of the root. The C-shaped canal could vary considerably in shape at different levels, and the incidence of two canals at the middle and apical was 21% and 80%, respectively. This study shows that radicular grooves may present relevant morphologic variations in the root canal system when the C-shaped root is present.

An In Vitro Evaluation of the Contents of Root Canals Obturated With Gutta Percha and AH-26 Sealer or Resilon and Epiphany Sealer

The purpose of this study was to compare the contents of root canals obturated with gutta percha and AH-26 sealer (Dentsply, Tulsa, OK) to canals obturated with the Resilon and Epiphany (Pentron, Wallingford, CT) system. Canal contents were assessed by determining the percentage of canal space occupied by core material, sealer, voids, and debris. Forty extracted human maxillary anterior teeth were instrumented, and the teeth were randomly assigned to either the gutta percha/AH 26 group or the Epiphany/Resilon group. Canals were obturated, and the teeth were subsequently embedded in resin and sectioned horizontally at 2, 4, and 6 mm from the anatomic apex. Sections were photographed by using a low vacuum scanning electron microscope. Image-J (Wayne Rasband; National Institute of Health, Bethesda, MD) software was used to quantify the proportion of core material, sealer, voids, and debris in each canal. Percentages and statistical comparisons for each method were compared. There were no significant differences found among the two groups in terms of the percentage of core (p = 0.9), sealer (p = 0.58), debris (p = 0.999), or voids (p = 1.00). Additionally, there were no differences in the percentage of core material, sealer, debris, or voids at any of the examined levels (2, 4, or 6 mm).

In vitro evaluation of endodontic debris removal as obtained by rotary instrumentation coupled with ultrasonic irrigation

The cleaning capacity of rotary Ni-Ti instrumentation using Profile GT files, coupled with irrigation energised by ultrasound, was evaluated. Thirty-six human mandibular incisors were instrumented in vitro using the crown-down technique with the Profile GT system to 1 mm from the anatomical apex to a size 30.04 taper file. The instrumented teeth were then divided randomly into four groups where various final irrigations were used: Group I: 100 ml of 1% NaOCl with a Luer-Lok syringe (control group); Group II, Group III and Group IV: final irrigation with 100 ml of 1% NaOCl energised by ultrasound for 1, 3 and 5 min, respectively. After biomechanical preparation, the apical thirds of the roots were submitted to histological processing and examination. The specimens were analysed at 40x magnification and the images submitted to morphometric analysis with an integration grid. anova showed a statistically significant difference (P < 0.01) between the irrigation techniques. Group I (Luer-Lok syringe) showed the highest percentage of debris (35.81 +/- 4.49) and was statistically different from the other groups energised by ultrasound: Group II (27.28 +/- 4.49), Group III (24.39 +/- 5.72) and Group IV (18.46 +/- 5.25). It was concluded that rotary instrumentation using Ni-Ti files associated with final irrigation of 1% NaOCl energised by ultrasound leads to better debris removal from the apical third of mesio-distally flattened root canal.

Evaluation of apical microleakage of teeth sealed with four different root canal sealers

Objectives:to compare the apical sealing ability of four root canal sealers. Materials and methods: forty extracted human maxillary canines were instrumented 1 mm short of the anatomical apex and randomly assigned to four groups (n=10), according to the root canal sealer used for obturation: Endofill, AH Plus, EndoREZ and Epiphany. Root canals were obturated with guttapercha points, except for the Epiphany group, in which resin points (Resilon) were used. The teeth were immersed in India ink for seven days and clarified using methyl salicylate. The extent of apical dye penetration was measured with a measuroscope in all aspects of the canal.Results:AH Plus (0.02 mm ± 0.07), Epiphany (0.00 mm ± 0.00) and EndoREZ (0.32 mm ± 0.62) did not differ statistically to each other (p>0.01). EndoFill presented the highest dye penetration mean (0.83 mm ± 0.73) and was statistically different from the other sealers (p<0.01).Conclusions:the resin-based root canal sealers presented lesser apical microleakage than the zinc oxide and eugenol based sealer. No statistical differences were observed among resin based sealers.

Morphology of the Physiological Foramen: I. Maxillary and Mandibular Molars

Information concerning the anatomy of the physiological foramen is limited. The aim of this study was to investigate the distance between the physiological and anatomical apex, accessory foramina frequency, and the shape and diameter of the physiological foramen in maxillary and mandibular molars. The apical anatomy of 523 maxillary and 574 mandibular molars from an Egyptian population was investigated by means of a computer-aided stereomicroscope (40 x magnification). The following results were obtained: