PubMed Health⌕ Search

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 667 records · Page 37Linked to original sources
PubMed2003

Evaluation of root-end cavity preparation using ultrasonic retrotips.

AIM: To evaluate and compare the efficiency of root-end preparations using ultrasonic retrotips coated with diamond and zirconium nitride. METHODOLOGY: Eighty-five extracted single-rooted teeth were root filled, and then resected 3 mm from their apices. Root-end cavities were prepared with KiS (zirconium nitride-coated retrotip), CT-5 (stainless steel tip) or diamond-coated (DC) ultrasonic retrotips, and 10 teeth served as controls. Thirty teeth were used for evaluation of the time required to prepare the root-end cavity, the number of microcracks produced on the resected surface and the number of dentinal tubule openings on the root-canal wall using scanning electron microscope (SEM) images. A further 55 teeth were used for evaluation of dye penetration following filling of the root-end cavities with Super EBA. The degree of dye penetration in millimetres was measured under the microscope after 7 days of immersion in India ink. Statistical analyses were performed using the one-way ANOVA and Scheffe's F-test as the post hoc test. RESULTS: There was no significant difference in the number of microcracks and dentinal tubule openings present in the root apices prepared by the three retrotips. The time required for root-end cavity preparation using the DC retrotip was significantly less than that using the other groups (P<0.01). Positive controls showed dye penetration throughout the length of the root-end cavity, and negative controls showed no dye penetration. There was no significant difference between the three experimental groups in dye penetration. CONCLUSIONS: In this laboratory study, the time required to prepare root-end cavities using KiS retrotips was the same as that using CT-5 retrotips, and longer than that using DC retrotips. There was no significant difference in the number of microcracks or dye penetration between the three kinds of retrotips.

Analysis of Variance↗
PubMed2003

Investigation of the marginal adaptation of root-end filling materials in root-end cavities prepared with ultrasonic tips.

AIM: To compare the surface topography of root apices following ultrasonic root-end preparation, and again after root-end fillings submitted to three different finishing techniques. METHODOLOGY: Eighty-one root-end cavities prepared ultrasonically in human canines, were divided at random into three test groups of 27 each. The cavities were filled with Super-EBA, IRM, or ProRoot-MTA and finished by ball burnishing. Eighteen roots from each group received a final finish with either a 30-fluted tungsten carbide finishing bur, or a Zekrya carbide 28 mm bur after storage in water at 37 degrees C for 24 h. The root-end surface topographies were reproduced by means of polyvinylsiloxane impressions and epoxy resin replicas. Scanning electron micrography (SEM) images of each replica were taken prior to and after root-end filling. An image analysis system was used to compare the alteration of the marginal chipping areas and to calculate the gaps located in the dentine/root-end filling interface. RESULTS: When a bur was used to finish the set materials, a significant (P < 0.05) area of marginal chipping was eliminated. The finishing technique did not significantly (P > 0.05) affect the incidence of gaps in groups root-end filled with MTA or IRM. Super-EBA and IRM retrofillings finished with a ball burnisher or a Zekrya bur displayed a significantly (P < 0.05) larger calculated gap area than roots filled with MTA. CONCLUSION: Under this in vitro study, the marginal adaptation of MTA was good with or without finishing procedures. Applying a finishing bur over the condensed and set IRM and Super-EBA created better marginal adaptation.

Aluminum Compounds↗
PubMed2003

A comparison of the minimum canal wall thickness remaining following preparation using two nickel-titanium rotary systems.

AIM: To examine in vitro whether Profile or Hero 642 nickel-titanium rotary instrument systems substantially reduce the minimum canal wall thickness present following root-canal preparation. METHODOLOGY: The canal anatomy of 26 mesial roots from mandibular molars with separate buccal and lingual canals was evaluated before and after instrumentation using the Endodontic Cube. Following access, working lengths were determined and then samples invested within the cube using acrylic resin. Canal cross-sections were subsequently prepared. Samples were then instrumented within the cube and pre- and post-instrumentation images of the sections were compared to determine the minimum canal wall thickness remaining after preparation. RESULTS: Buccal and lingual canals within the sections from each level (coronal to apical) showed a reduction in minimum canal wall thickness after instrumentation. No statistically significant differences in canal wall thickness were found between the two systems at any level of the root. CONCLUSIONS: Instrumentation with either of the two systems under investigation did not compromise canal wall thickness. Pre-operative canal wall thickness was found to be the most significant factor determining the minimum canal wall thickness after preparation.

Analysis of Variance↗
PubMed2001

Quantitative analysis of apical root resorption by means of digital subtraction radiography.

OBJECTIVE: This study was performed to assess the diagnostic and quantifying ability of digital subtraction images for simulated apical root resorption, as well as to compare the diagnostic accuracy of conventional intraoral radiographs with digital subtraction images for this condition. STUDY DESIGN: Digital and intraoral radiographs of 10 sound maxillary central incisors and those with simulated apical root resorption were taken with varying horizontal and vertical angulations of the x-ray beam. Paired t tests were used to compare the lengths of the sound teeth on the images with their actual lengths, and the estimated amount of simulated apical root resorption was compared with the actual amount of tooth loss by means of Emago software. The diagnostic accuracy for detecting lesions was also evaluated on conventional intraoral radiographs and digital subtraction images through receiver operating characteristic (ROC) analysis. RESULTS: There were no statistically significant differences between the actual lengths and those measured on the reconstructed images of the sound teeth. The calculated amounts of apical root resorption showed no statistically significant differences in comparison with the actual amounts (P >.05). The diagnostic accuracy of the conventional intraoral radiographs in detecting the lesions was low (ROC area = 0.6446). CONCLUSION: A quantitative analysis of small amounts of apical root resorption can be performed by means of digital subtraction radiography.

Humans↗
PubMed2001

An in vitro experiment on the effect of an attempt to create an apical matrix during root canal preparation on coronal leakage and material extrusion.

OBJECTIVE: A common approach to creating an apical matrix (apical stop) in the apical dentin is to enlarge the root canal to 3 sizes greater than that of the first file that binds at the working length. The aim of this study was to test the hypothesis that this procedure will reduce the amount of material extruded and the leakage along the apical root fillings. STUDY DESIGN: The canals of half of 120 maxillary and mandibular canines were prepared to the apical foramen through use of the serial shaping technique; the apical matrix creation procedure was not used. Each of the other 60 canals was prepared to 1 mm short of the apical foramen, and the canal was enlarged to at least 3 sizes greater than that of the first binding file to create an apical matrix. All the canals prepared with and all the canals prepared without the apical matrix creation procedure were obturated with laterally or vertically compacted cold or warm gutta-percha. In the leakage test, after post space preparation, the amount of fluid transport along the apical root fillings was measured. In the material extrusion test, the number of teeth with gutta-percha extrusion was recorded and the weight of the apically extruded materials was measured. RESULTS: In both the leakage and the extrusion tests, no significant difference was found between canals prepared with and canals prepared without the apical matrix creation procedure. CONCLUSION: The hypothesis that a procedure to enlarge root canals to 3 sizes greater than that of the first binding file will reduce the amount of filling materials extruded and the leakage was not proved, as our results show.

Chi-Square Distribution↗
PubMed2002

A comparison of phosphor-plate digital images with conventional radiographs for the perceived clarity of fine endodontic files and periapical lesions.

OBJECTIVE: We sought to compare digital images with radiographs for the perceived clarity of small endodontic file tips at 2 different working lengths, as well as for the visualization of periapical bone lesions. STUDY DESIGN: Standardized conventional radiographic and phosphor-plate digital images were taken of 20 extracted permanent mandibular molars with 06 K-files placed in the distal root canal either 2 mm short or flush with the apical foramen. Similar images were obtained from mandibles with teeth that demonstrated large (n = 10) or small (n = 10) periapical lesions. Four evaluators ranked the clarity of the digital image with that of the radiograph. Results were analyzed by using the 2-sided sign test, ordinal logistic regression, and the kappa test. RESULTS: The perceived clarity of an endodontic file tip, at any position, and of a small or large periapical lesion was significantly (P < .01) less on all digital images compared with conventional films. CONCLUSION: Evaluator ratings indicated that the perceived clarity of fine endodontic files and periapical lesions was significantly less with phosphor-plate digital images than with conventional radiographs.

Dental Instruments↗
PubMed2002

Ciliated epithelium-lined radicular cysts.

OBJECTIVE: This report describes 3 cases of ciliated epithelium-lined radicular cysts among 256 apical periodontitis lesions and also illustrates the occurrence of an Actinomyces-infected periapical cyst. STUDY DESIGN: Serial and step serial sections of 256 plastic-embedded root apices with attached apical periodontitis lesions that were prepared for a previous investigation were reviewed for the presence of ciliated epithelium-lined radicular cysts. The lesions that were found to have such epithelial lining were examined in a transmission electron microscope to elaborate the fine structure of the ciliated cells. RESULTS: A total of 3 ciliated columnar epithelium-lined cysts was found among the 256 apical periodontitis lesions examined. Two of the lesions also contained stratified squamous epithelium. All 3 lesions affected maxillary premolars. One of the lesions was a true cyst, and the other 2 were periapical pocket cysts. The lumen of 1 of the latter revealed the presence of typical "ray-fungus" actinomycotic colonies. CONCLUSION: Although the stratified squamous component of the epithelia that lined the radicular cysts reported here may be derived from the cell rests of Malassez, the ciliated epithelial cells may be of sinus origin. Microbial agents from diseased root canals can advance into radicular cysts, particularly in pocket cysts, with the possible threat of such infection in upper posterior teeth spreading into the maxillary sinus.

Actinomyces↗
PubMed2002

An 18-month longitudinal study on a new silicon-based sealer, RSA RoekoSeal: a leakage study in vitro.

OBJECTIVE: Because leakage along root fillings may increase or decrease during the long period after filling, the accumulated leakage data measured repeatedly after filling are clinically more relevant than the data measured just once shortly after filling. The aim of this study was to determine the long-term sealing ability of a recently developed root canal sealer RSA RoekoSeal (Roeko Dental Products, Langenau, Germany). STUDY DESIGN: Eighty extracted human mandibular premolars were equally divided into 4 groups (n = 20) and root canal instrumented. Canals in group 1 were obturated with laterally compacted gutta-percha points and RSA, in groups 2 to 4 with vertically compacted warm gutta-percha using RSA in group 2, Pulp Canal Sealer (Kerr, Romulus, Mich) in group 3, and no sealer in group 4. With the use of a fluid transport model, leakage along entire root fillings was measured before post space preparation. After post space preparation, leakage along the remaining apical root fillings was measured repeatedly at 1 week, 1, 2, 6, 12, and 18 months respectively and recorded in microliters per day. RESULTS: Before post space preparation, groups 1 and 2 leaked significantly less than groups 3 and 4 (P = .001), whereas no significant difference existed between the groups 1 and 2 (P = .317) or between the groups 3 and 4 (P = .074). For each group, a summation of the leakage at all time intervals after the post space preparation showed that the 2 RSA groups leaked significantly less than the other 2 groups (P =.000). However, no significant difference existed between the 2 RSA groups (P = .993) and between the groups 3 and 4 (P = .149). CONCLUSION: RSA used in combination with either cold laterally compacted or warm vertically compacted gutta-percha provided a consistent seal during a period of 18 months.

Bicuspid↗
PubMed2005

Development and characterization of an animal model of dental sinusitis.

CONCLUSION: The results of this study confirm that the present rabbit model of dental maxillary sinusitis (dMxS) is reproducible and simulates human dental sinusitis with respect to initiation, progression and inflammation. It is applicable to further studies of sinusitis of odontogenic origin. OBJECTIVES: To induce acute dMxS in rabbits by using their own oral microflora to create a periapical infection and to follow morphological, radiographic, bacteriological and histological changes to the sinus mucosa. MATERIAL AND METHODS: The experimental animals comprised 26 New Zealand White rabbits. Maxillary premolar root canals were identified bilaterally and the continuously growing germs of the roots were severed by diathermy. The animals were randomized into 2 groups: in Group 1 (n=20) the teeth were left open for the entire study period; in Group 2 (n=6) the root canals were sealed 1 week after the initial intervention. The animals in Group 1 were sacrificed at intervals ranging from 2 h to 9 months after intervention. All animals in Group 2 were sacrificed 6 months after intervention. After macroscopic and radiographic examination, post-mortem inspection of the paranasal sinus cavity and maxillary complex and microbiological sampling, the entire nasal sinus complex with the hard palate in situ was resected and processed for serial coronal sectioning. RESULTS: In Group 1, after 3 months, the radiographic changes ranged from widening of the periodontal space to bone reaction. At sacrifice, changes in the sinus mucosa ranged from signs of mucosal inflammation to purulent dMxS. Microbial growth, predominantly Gram-negative aerobes, increased over time. In Group 2, the findings were generally more pronounced. Anaerobic microorganisms were predominant. In both groups the findings were consistent with dMxS.

Animals↗
PubMed1997

The carbon dioxide laser as an aid in apicoectomy: an in vitro study.

OBJECTIVE: To achieve the required goal of optimally sealing the apical section and the root-canal when performing an apicoectomy, the authors decided to use the CO2 laser as an additional aid. SUMMARY BACKGROUND DATA: The CO2 laser has previously shown to have an excellent sealing effect on dentin surfaces. METHODS: In this in vitro study, the authors examined the effects of CO2 laser application in apicoectomies with the help of color penetration tests and scanning electron microscopic (SEM) examinations. Sections and root canals were irradiated with low power (0.5 W) in continuous wave mode for totally 20 sec. The thermal stress for the adjacent tissues attaching thereto is moderate as shown by infrared-spectroscopy. RESULTS: A comparison with nonirradiated samples revealed that CO2 laser irradiation reduced color penetration at the section to a minimum. Also, irradiation of the root-canal wall resulted in satisfactory sealing of the surface. These findings were supported by the results of the SEM examinations. CONCLUSIONS: CO2 laser treatment optimally prepares the tooth for final intraoperative filling because of sealing of the dentinal tubules, the resultant elimination of niches for bacteria and the sterilizing effect of the laser.

Apicoectomy↗
PubMed1998

Studies on the removal of debris near the apical seats by Er:YAG laser and assessment with a fiberscope.

OBJECTIVES: The purposes of this study were to investigate the effect of Er:YAG laser to remove debris near the apical seats in root canals and to evaluate the efficacy of a fiberscope for the assessment of remnant debris on the root canal wall in vitro. SUMMARY BACKGROUND DATA: There has been no report to evaluate residual debris in root canals after Er:YAG laser irradiation using a fiberscope. METHODS: After cleansing and shaping by a one step back method with the alternative irrigation of hydrogen peroxide and sodium hypochlorite solution, 80 extracted single root human teeth with straight canals were randomly divided into four groups. The teeth of groups 1, 2, and 3 were irradiated by Er:YAG laser at the parameters of 1 W, 2 W, and 3 W, respectively. Group 4 was comprised of control specimens that were not lased. After laser irradiation, the remnant debris on the apical portions of all root canals was evaluated by fiberscopy. The teeth were then bisected longitudinally, and the specimens were observed by stereoscopy and scanning electron microscopy (SEM). The degree of remaining debris on the apical seats was scored. RESULTS: The degree of remaining debris observed by fiberscopy coincided with the results by SEM. There was no significant difference between groups 1 and 4, and also between groups 2 and 4, but the remaining debris in group 3 was significantly decreased after Er:YAG laser irradiation compared with that in group 4 (p < 0.01). CONCLUSIONS: These results suggest that Er:YAG laser irradiation is effective for removal of debris near the apical seats and that a fiberscope is useful for the evaluation of the remaining debris near the apical seats of intact teeth.

Dental Pulp Cavity↗
PubMed1999

Study on apical leakage of the teeth after argon laser treatment and obturation.

OBJECTIVE: This study was performed to compare the apical leakage degree after laser treatment and obturation with that without laser treatment, and to evaluate the efficiency of argon laser irradiation in removing debris and smear layer from the prepared root canal walls in vitro. SUMMARY BACKGROUND DATA: There has been no report of laser effect on apical leakage after laser treatment and obturation. METHODS: Fifty-six human extracted single root teeth were used in this study. Teeth were divided into four groups of 14 teeth each and prepared up to a #60 K-file size at 1 mm short of the apical foramen using a step-back technique. Argon laser at the wavelength of 470 nm and at the output of 0.3 W was irradiated at apical stop for 1, 2, or 3 seconds at the continuous mode. In each group, ten teeth for the microleakage study were obturated and immersed in rhodamine B solution for 48 hours at 37 degrees C, and the others were used for the observation by scanning electron microscopy (SEM). All teeth were bisected longitudinally and observed by stereoscopy or SEM. RESULTS: The apical leakage degree after laser treatment and obturation was reduced compared to that in the control, but not significantly (p > 0.05). However, debris and smear layer in the laser-treated groups were removed from apical stop even at low energy density. CONCLUSIONS: These results suggest that apical leakage after argon laser treatment is not reduced significantly, but that argon laser is useful for removing debris and smear layer from root canals.

Dental Leakage↗
PubMed1999

A comparative study on the effects of three types of laser irradiation at the apical stop and apical leakage after obturation.

OBJECTIVE: The purposes of this study were to determine the degree of apical leakage using a dye penetration method after argon, pulsed Nd:YAG with or without black ink, or Er:YAG laser treatment and obturation, and to compare the results of three types of laser irradiation in vitro. SUMMARY BACKGROUND DATA: There have been only a few reports of the laser effect on apical leakage after laser treatment and obturation. METHODS: Seventy-five human extracted single root teeth were divided into five groups of 15 teeth each and prepared up to a #60 K-file size. One group served as the control and was not irradiated. The other four groups were irradiated with an argon laser at 0.3 W for 3 seconds at continuous mode, pulsed Nd:YAG laser at 2 W and 20 Hz for 4 seconds with or without black ink, and Er:YAG laser at 50 mJ per pulse and 4 Hz for 5 seconds. In each group, ten teeth for the apical leakage study were obturated and immersed in rhodamine B solution for 48 hours at 37 degrees C, and the others were used for the observation by scanning electron microscopy (SEM). All teeth were longitudinally bisected and observed by stereoscopy or SEM. RESULTS: After pulsed Nd:YAG laser treatment with black ink and obturation, the apical leakage degree (mean score: 0) was reduced compared to that in the control (mean score: 1.2) significantly (p < 0.05). SEM findings showed that specimens irradiated by pulsed Nd:YAG laser with black ink presented clean root canal walls with debris and smear layer evaporated, melted, fused, and recrystallized in most cases. CONCLUSION: These results suggest that pulsed Nd:YAG laser irradiation with black ink at the apical stop is useful for the reduction of apical leakage after obturation.

Dental Leakage↗
PubMed1996

A method of measuring the apical base.

The maxillary and mandibular apical base areas were measured, using a gnathograph, on the study casts of 156 adults and children representing Class II division 1, Class II division 2 and Class III malocclusions. There were significant differences between the groups at each age. The maxillary apical base areas tended to be smaller for the adults than for the children in all three occlusal classes. By contrast, the mandibular apical base areas tended to be larger for the adults than for the children, except in Class II division 1 malocclusion. Following a logarithmic transformation to stabilize the variance, regression lines were fitted to relate the size of the maxillary and mandibular apical bases to one another, for the malocclusion groups within each age group. The method gives additional information regarding the degree of apical base discrepancy in a given case, but more work is required before it can be used as a diagnostic tool.

Adolescent↗
PubMed1998

Apical root resorption during orthodontic treatment of patients with multiple aplasia: a study of maxillary incisors.

The aim of this study was to evaluate the risk of root resorption during orthodontic treatment of patients with aplasia, and to analyse the relative importance of some anamnestic and treatment variables. The subjects comprised 68 orthodontically treated patients with 1-16 congenitally missing teeth. The age of the patients was 11-20 years (mean 15 years). All patients were treated with fixed edgewise appliances. The purpose of the orthodontic treatment varied: to create optimal conditions for prosthetic restorations or osseointegrated implants, or to achieve aesthetic and functional alignment of teeth in less severe cases. The degree of root resorption was assessed before and after treatment from intra-oral radiographs of the maxillary incisors using a scale of 0-4. In all, 186 maxillary incisors were evaluated. The degree of apical root resorption was significantly greater in cases of multiple aplasia (4-16 missing teeth) than in those with only one to three missing teeth. Root form, treatment time with rectangular wires and intermaxillary elastics, and total treatment time were significantly related to root resorption. Discriminant analysis disclosed that the following variables were the most important determinants of root resorption: number of missing teeth, root form, and time with rectangular archwires and intermaxillary elastics. It is concluded that there is a high risk of apical root resorption during orthodontic treatment in patients with multiple aplasia (four or more teeth), in particular in teeth with an abnormal root form and lengthy treatment with elastics and rectangular archwires.

Adolescent↗
PubMed2003

The effect of Fränkel's function regulator type III on the apical base.

Dento-alveolar and skeletal effects of orthopaedic treatment have always been the subject of controversial scientific discussions. The objective of this retrospective study was to demonstrate the changes in the dental arch and the apical base of both jaws following therapy with Fränkel's function regulator type III (FR III). For this purpose, 42 Class III patients (28 females, 14 males, mean age 7.5 years) were selected according to strict criteria. The control group consisted of 16 patients (eight females, eight males, mean age 8.3 years) with minor malocclusion symptoms. Study models of all patients at the beginning and end of treatment were evaluated using a sophisticated measuring system. Apart from common parameters of model analysis, cusp inclination of the first molars, and apical bases of the maxilla and mandible were recorded to facilitate a comprehensive evaluation of treatment effects (including growth). The FR III stimulated the development of the maxilla, thus resulting in a more physiological growth pattern. Mandibular prognathism, however, was still discernible after therapy in the Class III patients, even though mandibular growth did not differ significantly between the two groups.

Case-Control Studies↗
PubMed2000

Three-dimensional reconstruction: a new method for the evaluation of apical microleakage.

The purpose of this study was the evaluation of a new method for studying apical microleakage by using a three-dimensional (3-D) reconstruction method. Fourteen human single-rooted mandibular teeth were used for this work. The canals were prepared with hand instruments by using the step-back technique. To supply a focus to the study of the method, the teeth were divided into two groups that were obturated using two different sealers. India ink was used for passive stain. Serial cross-sections 0.75 mm thick were taken from each specimen by using a special microtome. Each section was photographed under a stereoscopic microscope. Each photograph was digitized and processed to obtain a 3-D reconstruction of the external surface of the teeth, their corresponding prepared root canals, and their apical microleakage. Sample size and experimental methods were not designed to make valid groups; however, apical microleakage was observed in both groups ranging between 2.25 to 8.25 mm height. The 3-D reconstruction method has proved to be a useful tool in the study of apical microleakage.

Carbon↗