SEARCH · PubMed Health

Results for “Tooth Apex”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 469 records · Page 26Linked to original sources

PubMed2004

Influence of instrument size on root canal debridement.

Files of Greater Taper (GT) are rotary nickel-titanium files of three tapers (0.06, 0.08, 0.10) with file tips of sizes 20, 30, and 40. The purpose of this study was to compare in an in situ model the efficacy of root canal debridement in the apical 3 mm when instrumenting to a GT size 20 or a GT size 40 at working length. Twenty matched human cadaver teeth with 32 canals were decoronated at the cementoenamel junction and instrumented with rotary Files of GT to either GT size 20 or GT size 40. Sodium hypochlorite, EDTA, and RC Prep were chemical aids for debridement. The teeth were extracted; decalcified; sectioned at 0.5 mm, 1.5 mm, and 2.5 mm from the apex; and prepared for histologic examination and quantification of remaining debris. No differences were found between each level within each apex size group; however, the GT size 20 group left significantly more debris in the apical third compared with the GT size 40 group. A regression analysis showed that the apical third cleanliness could be predicted mainly by instrument size and to a lesser extent by the canal length. Irrigant volume, number of instrument changes, and depth of penetration of irrigation needle were not likely to explain differences in debridement.

Cadaver↗

PubMedDate not supplied

A closer look at diagnosis in clinical dental practice: part 4. Effectiveness of nonradiographic diagnostic procedures and devices in dental practice.

This article, the fourth in a series, examines nonradiographic procedures and devices such as standard clinical and visual examination, apex locators, vitality testers and colour shade guides in light of the tools described in the first 2 articles in the series. A variety of nonradiographic indices and scales are used in detecting periodontal disease and monitoring and assessing its treatment. The reliability of these diagnostic procedures directly affects treatment success, decisions to initiate more aggressive clinical interventions, and the ability to make an informed prognosis about the course of the disease. However, in many instances, the dependability of the measurements remains to be established.

Benzoylarginine-2-Naphthylamide↗

PubMed2001

[In vitro comparison of an electronic root canal length measuring device and the radiographic determination of working length].

The objective of this study was to evaluate the accuracy of an electronic root canal length measuring device (AFA Apex Finder, Analytic Technology, Orange, USA) and to compare the results with those obtained using handfiles evaluated radiographically using 146 extracted teeth with mature single roots. Root canal lengths were determined electronically with files cemented to their lengths. A radiograph in long cone technique with the inserted root canal instrument was performed. The apical point of working length was determined 1 mm coronally of the radiographic apex. The apical part of root surfaces was removed to expose the root canal with the inserted probe tip. The distance between measuring file tip and the apical constriction was measured using a microscope. In 77.2% of the evaluated radiographs the determined apical point of working length was found in a range of +-0.5 mm from the apical constriction. In 98.5% of the results of electronic determination of working length, the distance between file tip and the apical constriction was less than 0.5 mm. The electronic root canal length measuring device provided significantly more accurate results than the radiographs.

Dental Pulp Cavity↗

PubMed2004

Topographic anatomy of the inferior wall of the maxillary sinus in Koreans.

Knowledge of the relationship between the root apex and the inferior wall of the maxillary sinus are crucial for diagnosing and treating a sinus pathosis as well as in assisting in dental implantation. Therefore, identifying the proximity between the root apex and the inferior wall of the sinus and clarifying the cortical thickness of the inferior wall of the sinus is essential for determining the topography of a spreading dental infection into the maxillary sinus. Accordingly, knowledge of the topography between the root apex and the inferior wall of maxillary sinus is important for diagnosing and planning dental implantation, endodontic procedures, and orthodontic treatment. This study was undertaken to clarify the morphological and clinical characteristics of the maxillary sinus, particularly the inferior wall of the sinus in Koreans, and to identify the relationship between the inferior wall of the maxillary sinus and the roots of the maxillary teeth. Twenty-four sides of the maxillae of hemi-sectioned Korean heads were used in this study. All specimens were decalcificated and sectioned coronally. On the sectioned specimens, 21 items were measured using an image analyzing system. The distances between the each root apex and the inferior wall of the maxillary sinus were measured. The distance from the root apex to the inferior wall of the sinus was the shortest in the second molar area and the longest in the first premolar area. The thickness of the cortical plate of the inferior wall of the maxillary sinus was thinnest in the first premolar area but it was thickest in the second premolar area. The vertical relationship between the inferior wall and the roots of the maxillary molars was classified into five types. Type I (the inferior wall of the sinus located above the level connecting the buccal and lingual root apices) dominated (54.5% in the first molar area, 52.4% in the second molar area). The horizontal relationship between the inferior wall of the sinus and the root apex was classified into three types. Type 2 (the alveolar recess of the inferior wall of the sinus was located between the buccal and lingual roots) was most common (80% in the first and second molar area). Overall, this study demonstrated the many anatomical characteristics and determined the relationships between the maxillary sinus and their surrounding structures. These findings may have an impact on the clinical management of patients.

Anatomy, Cross-Sectional↗

PubMed1998

Coexpression of vasoactive intestinal polypeptide and substance P in reinnervating pulpal nerves and in trigeminal ganglion neurones after axotomy of the inferior alveolar nerve in the rat.

The effect of this axotomy on the expression of vasoactive intestinal polypeptide (VIP) in trigeminal ganglion neurones and nerve fibres in the first molar was examined immunohistochemically 3 weeks postsurgically in rats. A distinct upregulation of VIP-like immunoreactivity was found in 3 to 4% of the neurones (mean dia., 20.9 +/- 0.45 microns; mean cross-sectional area, 367 +/- 13.2 microns 2) in the mandibular region after axotomy. An almost complete coexpression was registered in neurones upregulated for VIP and growth-associated protein 43. Coexpression of VIP and substance P (SP) was found in a small number of the immunoreactive (IR) small-sized neurones, mainly in those in which VIP and SP were both weakly immunoreactive. In the uninjured ganglion, weakly labelled VIP-positive granules were frequently traced at high magnification in the cytoplasm of small neurones. No VIP-IR fibres were found in the control molar pulp, except for a few in the root pulp near the apex. However, 3 weeks after axotomy, a number of VIP-containing nerve fibres were found in the molar pulp and apical periodontium. Coarse VIP-IR fibres directed towards the odontoblast layer were a common finding. In some of these fibres VIP was shown to colocalize with SP. These results indicate that VIP is clearly expressed and transported in regenerating primary afferent neurones after axotomy of the inferior alveolar nerve.

Animals↗

PubMed2005

Effects of intracanal carbon dioxide laser irradiation on cultured human fibroblasts.

OBJECTIVE: The purpose of this study was to evaluate, under various conditions, the damage that might occur to viable cells after CO2 laser irradiation of the root canal. STUDY DESIGN: A laser tip was placed within the root canal of extracted human teeth that were positioned above cultured fibroblasts (NB cells), and then irradiation was applied. The irradiation modes used were either pulse (40 pps) or super-pulse (151 pps). The laser energy was set at 32 J in both modes, and the tip of the laser beam was positioned to a point 2 mm from the fibroblasts. RESULTS: When the pulse mode irradiation was applied, there was significant difference (P < .05) in the percentage of viable cells between teeth with closed apical foramen (1-mm wall between root canal and root apex) and the #15 group (No. 15 K-file used), #30 group (No. 30 K-file), or #50 group (No. 50 K-file). The difference between the #30 group and the #50 group (P < .05) was also significant. The larger the diameter of the apical foramen became, the lower was the percentage of viable cells. CONCLUSION: If a CO2 laser irradiates a root canal system enlarged to within 1 mm of the root canal length, little damage to the periapical tissues would be expected to occur.

Carbon Dioxide↗

PubMed1998

Shaping ability of Quantec Series 2000 rotary nickel-titanium instruments in simulated root canals: Part 2.

The aim of this laboratory based study was to determine the shaping ability of Quantec Series 2000 nickel-titanium rotary instruments in simulated root canals. A total of 40 canals with four different shapes in terms of angle and position of curve were prepared with Quantec Series 2000 instruments using the technique recommended by the manufacturer. Part 2 of this report describes the efficacy of the instruments in terms of prevalence of canal aberrations, the amount and direction of canal transportation and overall post-operative shape. Pre- and post-operative images of the canals were taken using a video camera attached to a computer with image analysis software. The pre- and post-operative views were superimposed to highlight the amount and position of material removed during preparation. Twenty-one zips and elbows were created during preparation with a significant difference (P < 0.005) between canal shapes in terms of the incidence of aberrations. Four perforations were created, with significant differences (P < 0.005) between the canal shapes; three ledges were also created but no danger zones. Highly significant differences (P < 0.001) were apparent between the canal shapes in total canal width at specific points along the canal length and in the amount of resin removed from the inner and outer aspects of the curve. Canal transportation at the end-point of preparation was most frequently directed towards the outer aspect of the curve, and without exception in canals with 40 degrees curves. At the beginning of the curve, transportation became more evenly balanced between the inner and outer aspect of the curve, although predominated towards the outer. Transportation was generally directed towards the outer at the orifice, especially in canals with 40 degrees curves. Mean absolute transportation at the various measurement points was less than 0.11 mm; significant differences occurred between canal shapes at the end-point of preparation (P < 0.0001), at the zips (P < 0.005), at the apex (P < 0.0001) and beginning of the curve (P < 0.05) and at the orifice (P < 0.0001). Under the conditions of this study, Quantec Series 2000 rotary nickel-titanium instruments created a relatively large number of aberrations including four perforations. The aberrations were created by the larger instruments implying that these should be used with caution at the full working distance. Scanning electron micrographs of these instruments revealed sharp instrument tips which appeared likely to predispose to transportation and the creation of defects along the outer aspect of severely curved canals.

Dental Instruments↗

PubMed1996

Endodontic retreatment: a rational approach to non-surgical root canal therapy of immature teeth.

The specificity of retreating immature teeth involves generally a broadly wide open apex and/or an inverted root canal conicity (apical opening wider than the root canal orifice), a periapical pathology leading often to a continuous canal exudation and thin and fragile dentinal walls. Nonsurgical endodontic retreatment of immature teeth consists at first in removing coronal and root canal iatrogenic obstructions in order to regain total canal patency. Apexification is then the treatment of choice, preceding a final gutta-percha obturation. The present article outlines a step-by-step rational approach to the root canal retreatment of immature teeth, pertaining to their biomechanical and pathological specificity.

Calcium Hydroxide↗

PubMed1997

Comparative in vitro study of apically extruded material after four different root canal Instrumentation techniques.

Forty newly extracted human upper central incisors were submitted to root canal instrumentation 1 mm from the apex using four different techniques: standard, step-preparation, crown-down, and ultrasound, with distilled and deionized water as the irrigating solution. The extrusion product was collected into a collecting device constructed for this purpose. Extrusion was calculated by the determination of the mass of extruded material. The step-preparation technique caused a larger amount of extrusion than the standard technique, which in turn caused greater extrusion than the crown-down and ultrasound techniques. All techniques used caused extrusion of material beyond the apical foramen.

Dental Leakage↗

PubMed1996

Apical canal sealing ability of calcium phosphate based cements.

The apical canal sealing ability of newly developed calcium phosphate cement (TDM-C), an equimolar mixture of tetracalcium and dicalcium phosphate dihydrate kneaded with McIlvain's buffer solution containing sodium carboxymethyl cellulose, was evaluated in a relative comparison with several recognized available products. The latter included BONETRIX (alpha-tricalcium phosphate mixed with citric acid and tannic acid), ARS (alpha-tricalcium phosphate and hydroxyapatite mixed with polyacrylic acid), and zine oxide eugenol sealer (ZOE). Canals of forty extracted human maxillary central incisors were prepared to the file size #70, divided into four groups, and obturated with each of the four above materials. Setting of all sealers took place either in 30% bovine serum solution or in phosphate buffered saline solution. Teeth were then decalcified and cleared to measure linear penetration of India ink from the apex into the canal. Results were statistically analyzed by Student's t-test. Surfaces of all materials, after setting, were also observed by scanning electron microscopy (SEM). We found that TDM-C, BONETRIX, and ZOE all showed excellent apical sealing ability whereas ARS was less effective in this regard. SEM analysis revealed micropores on the surface of every apatitic product, but ZOE was free of such porosity. It was concluded that TDM-C and BONETRIX may prove clinically useful as root canal sealant materials.

Calcium Phosphates↗

PubMed2001

An in vitro evaluation of the accuracy of the root ZX in the presence of various irrigants.

The purpose of this study was to evaluate the accuracy of the Root ZX in vitro in the presence of a variety of endodontic irrigants. The in vitro model, described by Donnelly, consisted of refrigerated gelatin made with 0.9% sodium chloride instead of water. The following irrigants were tested: 2% lidocaine with 1:100,000 epinephrine, 5.25% sodium hypochlorite, RC Prep, liquid EDTA, 3% hydrogen peroxide, and Peridex. A total of 30 extracted, single-rooted teeth were used. The experimental measurements in the presence of the various irrigants were compared with the actual canal lengths. The present data indicate that the Root ZX electronic apex locator reliably measured canal lengths to within 0.31 mm and that there was virtually no difference in the length determination as a function of the seven irrigants used. These results strongly support the concept that the Root ZX is a useful, versatile, and accurate device for the determination of canal lengths over a wide range of irrigants commonly used in the practice of endodontics.

Analysis of Variance↗

PubMed1999

A method of adapting gutta-percha master cones for obturation of open apex cases using heat.

CLINICAL TECHNIQUE: It is generally accepted that the success of root-canal treatment is mainly dependent on the proper cleaning, shaping and hermetic obturation of root canals. Obturation of the root canal is of importance as 60% of endodontic failures are attributable to incomplete obliteration of the root-canal system. The clinical application of many obturation techniques used today demands the preservation of the natural apical construction or the preparation of an artificial equivalent during chemo-mechanical preparation. However, in clinical practice there are cases where the apical foramen is wide because of over-instrumentation, root-end resection during periradicular surgery, root resorption or because the apex of the root is incompletely formed. Thus the preparation of an artificial apical stop is very difficult to achieve. It is a common experience that performing usual gutta-percha condensation techniques in such canals often results in overfilling and therefore special obturation techniques are needed. Some clinical cases of teeth with wide apical foramen treated by a special obturation method are presented in this paper. In this method the end point of the primary gutta-percha cone is elasticized with a heated instrument and inserted into the root canal to record the internal morphology of the apical portion.

Gutta-Percha↗

PubMed2001

Methodological considerations in the determination of working length.

AIM: The aim of this study was to evaluate the diagnostic efficacy of an electronic system for the determination of working length, in comparison with two radiological methods (conventional film and digital radiography). METHODOLOGY: The study sample consisted of 28 root canals belonging to 20 human mandibular teeth. A comparison was made between the working length measurements obtained by two radiological methods (conventional film and digital radiography) and an apex locator, using as gold standard the observation of the file position within the root following selective grinding of the root tissue. RESULTS: The electronic method was satisfactory in 67.8% of cases, versus 50.6% and 61.4% for the conventional and digital radiological methods. respectively. No statistically significant differences occurred between the techniques according to the chi-squared and Kruskal-Wallis nonparametric tests. CONCLUSIONS: None of the techniques was totally satisfactory in establishing the true working length. There were no differences between the techniques investigated.

Analysis of Variance↗

PubMed1996

Examination of external apical root resorption with scanning electron microscopy.

UNLABELLED: External apical root resorption may be evident histologically but not visible radiographically until it is advanced. If working length is determined without considering this resorption, overinstrumentation or overfilling may occur. OBJECTIVE: This study used scanning electron microscopy to examine the appearance and to compare the incidence of external apical root resorption in 40 teeth with differing pulpal and periapical diagnoses. STUDY DESIGN: After extraction, 46 roots were sectioned horizontally 6 mm from the anatomic apex and prepared for scanning electron microscopy examination. Photomicrographs were scored by two blinded independent examiners. Apical resorption was categorized as: none, partial, or complete. Presence or absence of a funneling appearance of the resorption was also recorded. RESULTS: Kruskal Wallis showed a significant difference in resorption between groups; teeth with irreversible pulpitis/normal periapex had the least resorption. Duncan's multiple range test found radiographic apical lesions to have more resorption than those without lesions; teeth with necrotic pulps had more resorption than those with vital pulps. CONCLUSION: Pulp necrosis with radiolucent apical pathosis is more likely to demonstrate resorption.

Chi-Square Distribution↗

PubMed2005

Buccal bone plate thickness of the Asian people.

Distances from the apex to the buccal bone plate were measured on the computed tomography (CT) images of 1806 teeth from 66 patients, using an image analyzer program (Image-Pro Plus, Ver. 4.0, Media Cybernetics). In the mandible, the mean distance from the distal apex of the mandibular second molar to the buccal bone plate was the largest distance measured, at 8.51 mm, followed by distance from the mesial root to the buccal bone (7.34 mm). In the mandibular first molar, the mean distal and mesial bone thicknesses were 5.18 mm and 4.09 mm, respectively. However, when there were two distal roots, the distance of the disto-lingual root to the buccal plate was found to be 9.52 mm, which constitutes the greatest measured thickness. In the maxillary buccal roots, the distances from the mesio-buccal and disto-buccal root of the second molar to the buccal bone plate were the largest, at 4.63 mm and 3.61 mm, respectively. The average distances from the palatal apex of the maxillary first and second molars to the buccal bone plate were 10.69 mm and 10.17 mm, respectively, while, from the palatal bone plate, average distances of 3.15 mm and 3.08 mm were measured. Special considerations, such as bony lid approach, lingual approach, or intentional replantation may be required, especially when a patient has a surgical need in the second molars and the disto-lingual root of the mandibular first molar, or in the palatal root of the maxillary molars.

Adolescent↗

PubMed1998

Apical extent of rotary canal instrumentation with an apex-locating handpiece in vitro.

PROBLEM: The Tri Auto ZX (J. Morita Co., Kyoto, Japan) is a cordless endodontic handpiece with a built-in apex locator that is programmed to reverse the direction of rotation when the file reaches a predetermined apical level or when torque becomes excessive. OBJECTIVE: The purpose of this investigation was to examine the apical extent of rotary canal instrumentation and the ability to maintain apical constriction with the Tri Auto ZX at different automated settings. STUDY DESIGN: In 60 extracted teeth, canals were measured to the apical constriction, first visually and then electronically with the Tri Auto ZX; then they were instrumented with nickel titanium rotary files. For the instrumentation, the automatic apical reverse mechanism of the handpiece was set to 1, 1.5, or 2; these settings correspond to different distances from the apical foramen. Instrumentation was carried out apically until rotation was reversed by the automatic apical reverse function; the instrumented length was then measured, and the canal was filled with gutta-percha and sealer. The integrity of the apical constriction was assessed by exposing the apical 4 mm of the canal and observing the dentin-cementum junction. Paired t-tests were used to compare the visually measured length, the electronically measured length, and the instrumented length for each tooth. RESULTS: On average, the electronically measured length was 0.54 mm shorter than the visually measured length (p < 0.05). When the automatic apical reverse mechanism's setting was 1, the instrumented length was 0.1 mm shorter than the electronically measured length; when the setting was 1.5, the instrumented length was 0.36 mm shorter than the electronically measured length (p < 0.01). Results were inconsistent when the setting was 2. CONCLUSION: Instrumentation with the automatic apical reverse feature set at 1 consistently approximated the apical constriction; however, the constriction was frequently enlarged.

Dental Alloys↗

PubMed1997

Prevalence of teaching apical patency and various instrumentation and obturation techniques in United States dental schools.

Maintaining an open apex beyond the apical constriction with an endodontic file during canal instrumentation is a concept that has been advocated by several authors and clinicians. To ascertain the prevalence of teaching the patency concept as well as various instrumentation and obturation techniques in the United States dental schools, a survey was conducted. Forty-eight out of a total of 53 dental schools (91%) responded to the survey. Results indicate that 50% of the schools surveyed teach the concept of patency to their undergraduates or graduates or both; 83% teach a step-back instrumentation technique; and 89.6% teach lateral condensation of gutta percha as their primary obturation technique.

Curriculum↗

PubMed1997

Effect of root canal contents on healing of teeth with dentin-bonded resin composite retrograde seal.

Healing results were compared among 551 infected roots apically sealed with a dentin-bonded resin composite (Gluma-Retroplast). These roots contained either 1) root filling to apex after resection, 2) insufficient root filling, or 3) empty root canals with necrotic pulp remnants. At 2- to 4-yr follow-up, complete bone healing was found to be 92%, 85%, and 81% in groups 1, 2, and 3, respectively. The results from groups 1 and 3 were significantly different, and the results from group 2 did not differ significantly from that of groups 1 or 3. Reasons for "Failures" were found to be mainly loose filling or uncovered canal. After 21 roots classified as "Failures" were reoperated, 76% of these showed "Complete Healing" after 1 yr.

Adult↗