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At least 397 records · Page 22Linked to original sources
PubMed1999

An in vitro comparison of two modern apex locators.

Two apex locators were compared regarding their ability to accurately locate the apical constriction in the presence of various canal fluids at different meter readings. Forty-one root canals were filled with 1% NaOCl, 3% H2O2, and 0.9% NaCl, respectively. Electronic working length (EWL) measurements were recorded with the apex locators Root ZX (meter readings: "Apex", "0.5", and "1") and Apit (meter readings: "Apex" and "3"). The deviation of the EWL from the apical constriction was determined. The proportion of measurements within +/- 0.5 mm of the apical constriction ranged between 0.76 and 0.85 for Root ZX at the meter readings "Apex" and "0.5," regardless of the canal contents. Apit consistently displayed shorter measurement values than Root ZX and reached the highest proportions at the meter reading "Apex": 0.59 (1% NaOCl), 0.61 (3% H2O2), and 0.68 (0.9% NaCl). In the presence of NaOCl, Root ZX provides the more accurate EWL measurements at the meter reading "0.5" and "Apex."

Dental Instruments↗
PubMed1996

Effects of aging on the endodontic system, reserve crown, and roots of equine mandibular cheek teeth.

OBJECTIVE: To document age-related changes in the morphology of the endodontic system, reserve crown, and roots of equine mandibular cheek teeth. DESIGN: Equine mandibular cheek teeth from horses of various ages were compared, using radiography, x-ray computed tomography, and histologic examinations. SAMPLE POPULATION: 48 right hemi-mandibles from horses 2 to 9 years old. PROCEDURE: Hemi-mandibles were radiographed, imaged by computed tomographic reconstruction, and reformatted. Histologic examination was used to identify and correlate tissue types. RESULTS: Permanent mandibular cheek teeth of the horse, at the time of eruption, consisted of an exposed crown and a reserve crown with a widely dilated apex. The endodontic system consisted of 5 or 6 pulp horns that connected to an expansive pulp in the reserve crown, which was confluent with the primordial pulp bulb surrounding the tooth's apex. At the time of eruption, mandibular cheek teeth did not have a distinct pulp chamber, roots, or evidence of root formation. However, within 2 years after eruption, mesial and distal roots and a pulp chamber were present. A distinct pulp chamber, communicating with the pulp horns and both root pulp canals, was identifiable for 4 to 5 years from the time of root formation. The endodontic system of cheek teeth, 6 to 8 years after eruption, consisted of 2 unattached compartments, made up of a root canal, pulp chamber, and 2 or 3 pulp horns. CLINICAL RELEVANCE: The age-related morphologic changes in equine mandibular cheek teeth have important implications for application of endodontic therapy in horses.

Aging↗
PubMed1997

Accuracy of apex locator.

An evaluation of the accuracy of the "Root ZX" apex locator was conducted on 20 single-rooted teeth that had been extracted because of severe disease or orthodontic treatment. After the pulp chamber had been accessed and the tooth length determined using the Root ZX apparatus, the file was fixed to the tooth with light-cured composite resin. After extraction, the tooth was longitudinally ground with a diamond bur until the file was visible. The distance between the file tip and the apical foramen was measured under a microscope (x 100). The results showed that the tip of the instrument reached the apical foramen in all teeth.

Adult↗
PubMed1998

Apical limit of root canal instrumentation and obturation, part 1. Literature review.

One of the major controversies in root canal therapy concerns the apical limit of instrumentation and obturation. The results of longitudinal prognostic studies, basic anatomical knowledge of the apical third of the root canal, and the histological pulp reaction to caries progression demonstrated the presence of a vital apical pulp remnant, even in the presence of a periapical lesion. Finally necrosis and bacteria establish themselves in the periapical lesion. All valid prognosis studies confirm the practice of staying short of the apex with a homogeneous obturation to obtain the highest success rate of 90-94% (when done by or under supervision of specialists; results in the general population had a failure rate greater than 50%). The location of the apical foramen(ina) related to root canal treatment most frequently ends short of the apex, often by several millimetres.

Dental Pulp↗
PubMed2006

Ex vivo accuracy of three electronic apex locators: Root ZX, Elements Diagnostic Unit and Apex Locator and ProPex.

AIM: To compare ex vivo the accuracy of three electronic apex locators (EALs): Root ZX, Elements Diagnostic Unit and Apex Locator and ProPex. METHODOLOGY: Electronic working length determination was carried out in 40 extracted teeth using an ex vivo model. After access preparation, a first operator determined the reference length (AL) for each tooth under a 30x stereomicroscope using the apical constriction as the apical landmark. All teeth were then measured with each EAL and the results obtained were compared with the corresponding AL. The AL was subtracted from the electronically determined distance. The measurements exceeding the AL were recorded as positive (long) and the measurements short of the AL were recorded as negative. Data were analyzed using the Friedman Test and Tukey multiple range test for nonparametric correlation amongst groups. Statistical significance was considered at P < 0.05. RESULTS: Comparing the differences between measurements obtained with the three EALs and those obtained with the stereomicroscope, the percentage of measurements within +/-0.5 mm of the AL was 97.37% (84.22% within 0.5 mm short of AL) for the Root ZX, 94.28% (88.57% within 0.5 mm short of AL) for the Elements and 100% (35.9% within 0.5 mm short of AL) for the ProPex. The mean difference between the AL and the lengths measured by the Root ZX, the Elements and the ProPex were, respectively, -0.157 +/- 0.228, -0.103 +/- 0.359 and 0.307 +/- 0.271 mm. CONCLUSIONS: The results of the present study confirm that the EALs determined the canal length within +/-0.5 mm from the apical constriction in the majority of cases. The majority of the ProPex readings were long.

Dental Pulp Cavity↗
PubMed2004

Electronic apex locators.

Prior to root canal treatment at least one undistorted radiograph is required to assess canal morphology. The apical extent of instrumentation and the final root filling have a role in treatment success, and are primarily determined radiographically. Electronic apex locators reduce the number of radiographs required and assist where radiographic methods create difficulty. They may also indicate cases where the apical foramen is some distance from the radiographic apex. Other roles include the detection of root canal perforation. A review of the literature focussed first on the subject of electronic apex location. A second review used the names of apex location devices. From the combined searches, 113 pertinent articles in English were found. This paper reviews the development, action, use and types of electronic apex locators.

Dental Instruments↗
PubMed2004

Electronic apex locator.

Locating the appropriate apical position always has been a challenge in clinical endodontics. The electronic apex locator (EAL) is used for working length determination as an important adjunct to radiography. The EAL helps to reduce the treatment time and the radiation dose, which may be higher with conventional radiographic measurements. According to recent publications, the accuracy of frequency-dependent EALs appears to be much higher compared with traditional-type EALs (simple resistance type or impedance type). This article reviews the history and the working mechanism of the currently available EALs, and suggests the correct usage of the apex locator for a better canal length measurement.

Dental Pulp Cavity↗
PubMed2006

Accuracy of the apex locating function of TCM Endo V in simulated conditions: a comparison study.

OBJECTIVE: The aim of this study was to evaluate the accuracy of the apex-locating function of the TCM Endo V and to compare the results to these of the Root ZX. STUDY DESIGN: Forty-seven extracted maxillary incisor teeth with mature apices and patent single root canals were used for the study. After the root surfaces were cleaned and access cavities were prepared, the true working lengths (TL) were determined with a #10 stainless steel file. All samples were mounted in an alginate model especially developed to test the apex locators. Both electronic apex locators were used according to the manufacturer's recommendations and adjusted to 0.5-mm accuracy to the apical foramen. EL(1) was designates as the working length measured with Root ZX and EL(2) was designated as the working length measured with TCM Endo V. A paired t test was used to statistically analyze the significance of the mean differences at the 95% confidence interval of the differences (P = .001) among TL, EL(1), and EL(2). RESULTS: There were no statistically significant differences between TL and EL(1), TL and EL(2), and EL(1) and EL(2) (P = .001). Both Root ZX and TCM Endo V gave similar results. CONCLUSIONS: TCM Endo V proved to be as reliable as Root ZX but the use of the device to determine the working length was not easy as Root ZX. Further studies are needed to compare TCM Endo V in clinical conditions with similar electric motor and apex locator combined devices.

Dental Instruments↗
PubMed2006

[Problems with working length determination during endodontic therapy].

Accurate working length (WL) determination is a crucial part of successful root canal therapy. Working length is the distance from the coronal reference plane to the apical constriction. The apical constriction, also referred to as cementodentinal junction, represents the transition between the pulpal and the periodontal tissues. It is widely accepted that canal preparation and filling should be terminated at that point. However, the location and form of the apical constriction are variable and not always detectable. Moreover, the available clinical methods used for WL measurements are also inaccurate. At present two methods are recommended in dental practice for determination of WL: radiographic technique, and by the means of electronic apex locators. Advantages and disadvantages of the two methods are discussed in this paper.

Electronics, Medical↗
PubMed1999

Effect of preflaring on Root ZX apex locators.

The Root ZX apex locator is an example of a generation of apex locators that identify the terminus of the canal by measuring a ratio between two electrical impedances. Studies have shown this device to have a high degree of accuracy. However, the manufacturer warns that the performance of these devices is limited by the presence of calcifications and dentinal shaving obstructions. An in vitro study was designed to determine if preflaring of canals would facilitate the passage of files to the apical foramen by eliminating cervical interferences and to see what effect this would have on the performance of the Root ZX apex locator. Thirty-two canals were divided into two groups. Group 1 was not manipulated before use of the Root ZX apex locator and served as control. In group 2, the canals were preflared before the use of the Root Zx apex locator. The working length files were secured in place and measured with the linear measurement tool used by the Visilog 5 imaging program. Results of this study suggest that preflaring of canals will allow working length files to more consistently reach the apical foramen (p = 0.015), which in turn increases the efficacy of the Root ZX apex locator.

Dental Instruments↗
PubMedDate not supplied

Determination of the morphological irregularities in the middle and apical 1/3rd region of the root canal system of permanent maxillary incisors.

A thorough knowledge of the root canal anatomy and an understanding of its variations from the normal are mandatory for the successful root canal therapy. The assessment and exploration of the accessory canal and apical delta is necessary to combat the persistent infection at the periapical area. The purpose of this study is to determine the morphological irregularities in the middle and apical 1/3rd region of the root canal system of maxillary incisors. A total of 100 maxillary incisors were decalcified, processed, sectioned at the middle and apical 1/3rd region and observed under an ordinary microscope. The frequency of accessory canals, apical delta and type of canal configuration were studied. Accessory canals were found in 5% of the teeth. There was absence of apical delta in all the specimens. Total specimens showed single canal extended from the pulp chamber to the apex (Type 1 canal configuration).

Coloring Agents↗
PubMed2003

Implementation of the two-stage operation technique for the autotransplantation of teeth with closed apexes--a preliminary report.

Transplantation of teeth with incompletely formed apexes demonstrates a statistically better retention than the transplantation of fully-formed teeth because of the possibilities for reinnervation and revascularisation. However, with regard to the autotransplantation of teeth with completely developed roots, routine endodontic treatment is proposed, as the possibility to retain the vitality of dental pulp is doubtful. In this work the author wishes to present the implementation of the two-stage technique for the transplantation of fully-formed teeth. Observations confirm the possibility for reinnervation and revascularisation occurring after autotransplantation of teeth with closed apexes, which should encourage a cautious approach to the question of routine endodontic treatment following autotransplantation.

Adolescent↗
PubMed2005

Determining the optimal obturation length: a meta-analysis of literature.

The purpose was to aid in determining termination of instrumentation and obturation. A meta-analysis was conducted as to success/failure of different obturation lengths. Inclusion criteria were (a) minimum follow-up of 2 yr, (b) data on obturation length, (c) definition of success/failure, (d) available data on success/failure, (e) radiographic evaluation. Correlations were made as to success/failure as related to length of obturation from the apex. When comparing group A (obturated 0-1 mm from apex) versus group C (obturated past apex) using the DerSimonian and Laird estimates, group A showed a marginally better (p < 0.10) success rate than group C by 28.8%. Group A had better success than group B (obturated >1 mm short); the difference was insignificant. The results were similar after controlling for study quality using a single random effects regression model. In conclusion, the meta-analysis indicated that a better success rate is achieved when treatment includes obturation short of the apex.

Dental Pulp Cavity↗
PubMed1997

Lower molar and incisor displacement associated with mandibular remodeling.

The purpose of this study was to quantify the amount of alveolar modeling at the apices of the mandibular incisor and first molar specifically associated with appositional and resorptive changes on the lower border of the mandible during growth and treatment. Cephalometric data from superimpositions on anterior cranial base, mandibular implants of the Björk type, and anatomical "best fit" of mandibular border structures were integrated using a recently developed strategy, which is described. Data were available at annual intervals between 8.5 and 15.5 years for a previously described sample of approximately 30 children with implants. The average magnitudes of the changes at the root apices of the mandibular first molar and central incisor associated with modeling/remodeling of the mandibular border and symphysis were unexpectedly small. At the molar apex, mean values approximated zero in both anteroposterior and vertical directions. At the incisor apex, mean values approximated zero in the anteroposterior direction and averaged less than 0.15 mm/year in the vertical direction. Standard deviations were roughly equal for the molar and the incisor in both the anteroposterior and vertical directions. Dental displacement associated with surface modeling plays a smaller role in final tooth position in the mandible than in the maxilla. It may also be reasonably inferred that anatomical best-fit superimpositions made in the absence of implants give a more complete picture of hard tissue turnover in the mandible than they do in the maxilla.

Adolescent↗
PubMed2002

Effect of electronic apex locators on cardiac pacemaker function.

The purpose of this study was to assess the effects of five electronic apex locators on pacemaker function in vitro. A Biotronik Actros DR+ pacemaker was evaluated at maximum sensitivity on a flat bench top. The pacemaker lead, electronic apex locator, and oscilloscope were connected across a 150-ohm resistor. Pace monitoring was carried out with a Biotronik EPR 1000 programmer and a Tektronix TDS 220 2-channel digital real-time oscilloscope. Four of five electronic apex locators tested did not cause inhibition or interfere with normal pacemaker function. It seems that electronic apex locators can be used safely in patients with pacemakers.

Dental Instruments↗
PubMed2002

SEM observations of resected root canal ends following apicoectomy.

The purpose of this study was to examine the apical foramen of root apices extracted during apicotomies. A total of 25 teeth extracted from 25 patients admitted to the Department of Conservative Dentistry at Tokyo Dental College's Chiba Hospital were used for the study. All patients were between 22 to 56 years of age at the time of the study, and each of the 25 cases was determined clinically on radiographs to be chronic apical suppurative periodontitis. Microsurgery was performed on all cases, and the extracted root apices were then observed using SEM. The results demonstrated a wide opening, greater than 350 microns as measured along the major axis, of the apical foramen in 80% of the cases. Various characteristics indicative of resorption were observed around the apical foramen. These features included those believed to have been caused by overinstrumentation during root canal treatment as well as irregularly shaped areas presumed to be apical lesions that had enlarged and eroded. We observed a high frequency of manifestations of cementum resorption surrounding the root apices of teeth with apical lesions. Furthermore, we concluded that in the majority of cases in the present study, due to the fact that the apical foramen exceeded normal opening dimensions as a result of overinstrumentation during root canal treatment or resorption around the root apex, prolongation of the lesions had occurred in response to direct contact of microbial infectious matter and tissues surrounding the root apex over a large area. The above finding suggested that, in cases in which the apical foramen is destroyed through overinstrumentation larger than #35 or in which the apical foramen opens up to dimensions greater than 350 microns due to pathologic resorption, surgical intervention may be indicated. On the other hand, in 64% of the cases, an accessory canal was observed in the root apical lesion. Based on this observation, the presence of an accessory canal in the root apex may contribute to some degree to the prolongation of the lesion.

Adult↗
PubMed2005

[Determination of canal length in endodontics].

Although the reliability of the electronic apex locator is agreed upon in the endodontic literature, the general practitioner has difficulties to integrate the device in his daily practice. The authors of this paper conclude that the apex locator should be used to confirm the information obtained from the pre-operatory radiograph (imperatively taken with the parallel technique) and they assert that the data obtained electronically have still to be interpretated. The apex locator can be considered an essential tool as long as its limitations are known.

Calibration↗