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At least 973 records · Page 54Linked to original sources
PubMed1994

Digitized slice interposition in forensic dental radiographic identification. An in vitro study.

Traditional methods of comparison involving the presence of missing teeth, dental restorations, and other pathological features may be difficult due to the reduction in dental restorations in today's population. This study demonstrates an alternative method of identification using digitized images. It utilizes anatomical structures such as dental root morphology and spatial relations of teeth roots and their supporting structures on simulated antemortem and postmortem radiographs as the basis for identification. A total of 39 mandibular specimens were used and two radiographs representing the antemortem and postmortem radiographs of each hemimandible were exposed by two operators using different x-ray generators. The radiographs were scanned and digitized. The identities of the antemortem and postmortem radiographs were kept from the operator. Following this, horizontal sections were digitally cut from the antemortem radiographs through the roots approximately halfway between the neck of the tooth and the root apex. This section was manipulated onto the postmortem radiograph by using a computer graphics program and a quantitative comparison of the alignment of normal dental anatomical landmarks was undertaken. The technique enabled perfect matching of all 39 specimens by antemortem and postmortem dental radiographs. The mean number of identifying points was 17.5 and the mean number of nonmatching points was 0.1. The mean concordance was 99.2% between the antemortem and postmortem radiographs.

Forensic Dentistry↗
PubMed2005

Facial and oral reconstruction following trauma and failed chin implant: a case report.

Functional and esthetic reconstruction of a patient with microgenia who sustained traumatic injury was successfully accomplished using Brånemark System osseointegrated implants (Nobel Biocare USA, Inc., Yorba Linda, CA) to support a permanent dental prosthesis following mechanical and biologic reconstruction of the anterior mandible and chin. A 25-year-old glycine chin implant previously used for facial esthetic enhancement had eroded the anterior cortical plate and migrated through the medullary bone, compressing the periosteum into the apex of the anterior tooth roots. Further destruction of the lingual cortex with risk of fracture was imminent. After removal of the chin implant, a cancellous bone graft was held in place with a titanium mesh frame. The prosthetic rehabilitation consisted of two phases of mandibular implant placement followed by the construction of a porcelain-fused-to-gold implant-supported fixed prosthesis, restoring the occlusal vertical dimension as well as appropriate lip support. Restoration of function was superior to the pretreatment condition.

Bone Resorption↗
PubMedDate not supplied

Case report: a large radicular cyst involving the entire maxillary sinus.

Cysts of the maxillary sinus of odontogenic origin have been well-documented in the literature. Most of these lesions involve the apex of the offending tooth and appear as a well-defined periapical radiolucency. Presented here is a case of an unusually large lesion, which involved the entire maxillary sinus and extended into the floor of the nose. The lesion also caused paresthesia on the affected side. The lesion was removed with conservative treatment without any postoperative complications.

Adult↗
PubMed2005

Accuracy of electronic apex locators in comparison to actual length--an in vivo study.

OBJECTIVES: The measurement precision of four electronic apex locators (Root ZX, Morita, Tokyo, Japan; Endy, Loser, Leverkusen, Germany; Justy II, Hager-Werken, Duisburg, Germany; Endox Lysis, Milan, Italy) was examined in the present in vivo study. METHODS: The root canal length of 40 single-rooted and multi-rooted teeth was determined with the four devices prior to tooth extraction. To determine the actual root canal length, the apical third was longitudinally sectioned, the root canal instrument was positioned and the apex was examined using a microscope. RESULTS: The average measurement deviation (+/-SD) in relation to the apical constriction was 0.3 mm (+/-0.6) for the Root ZX, 0.7 mm (+/-1.0) for the Endy, 0.2 mm (+/-0.7) for the Justy II and 1.3 mm (+/-1.7) for the Endox. The limit of +/-0.5 mm from the apical constriction was attained by the Root ZX in 78%, by the Endy in 67%, by the Justy II in 80% and by Endox in 31% of all measurements. CONCLUSIONS: The latest generation of apex locaters provide the clinician with an accurate and useful adjunct for the determination of root canal length.

Dental Pulp Cavity↗
PubMed1987

Three-dimensional presentation of the fibroblast progenitor compartment in the periodontal ligament of the rat incisor.

The purpose of this study was to determine the shape, size, and spatial configuration of the fibroblast progenitor compartment (PC) of the tooth-related periodontal ligament (PDL). Five albino rats (weight 200 gm) were killed 1 hr following intraperitoneal injection of 3H-thymidine. The incisors were decalcified, embedded in glycol-methacrylate, and sectioned serially, perpendicularly to the long axis of the tooth. Ten 2-microns-thick sections along each tooth were selected, processed autoradiographically, and the distance from the apex measured. Labeled and unlabeled fibroblasts were counted in 8 x 80-microns consecutive layers. Cell density (CD) and labeling index (LI) were plotted on a three-dimensional system of coordinates depicting the directions: apex to incisal edge, cementum to bone, and cemento-enamel junction (CEJ) to lingual tooth surface. The CD along the tooth was constant, except at 2-6 mm distant from the apex, where it was significantly higher. The highest concentration of cells around the tooth was in the 20-microns region adjacent to the cementum. The PC on the mesial and lateral tooth sides extended 1-4 mm from the apex, with the LI peak (6.5%) occurring at 2 mm. The PC on the lingual tooth side was located at 2-6 mm from apex, peaking (14%) at 4 mm. On the cementum-bone coordinate, the PC extended to about 50 microns from the cementum on all sides, the LI peak appearing at a distance of 20-40 microns from the tooth. The LI was consistently higher on the lingual side than on the mesial and lateral aspects.

Animals↗
PubMed1993

Expression of neural cell adhesion molecule (NCAM) during the first molar development in the mouse.

NCAM, the neural cell adhesion molecule, was immunolocalized in the mandibular first molar tooth germ of the mouse. NCAM was first detected in the tooth germ of the late bud stage, where only the cells in the outer part of the condensed mesenchyme (primitive dental follicle) exhibited faint immunoreactivity. The entire dental follicle was intensely immunostained for NCAM from cap stage to the stage when root formation started. During root formation, NCAM disappeared from the follicular tissue surrounding the cervical root as well as from the part covering the crown top. This loss of NCAM proceeded in the direction of the root apex, but even after the tooth had achieved functional occlusion, NCAM was still expressed by the mesenchymal cells adjacent to the root apex. On the other hand, NCAM was negative in the dental papilla until birth. After birth, NCAM-immunoreactivity appeared in the basal portion of the dental papilla, but this NCAM-positive area gradually diminished in width during the root elongation. Instead, another NCAM-positive zone appeared in the core of the pulp during root formation. Even in the tooth that had already erupted, the pulp core contained cells that were strongly positive for NCAM immunostaining. In addition to its expression in the above two mesenchymal cell lineages, NCAM was transiently expressed by epithelial components of the tooth germ, some of the cells of the dental lamina and the enamel organ. The results suggest that NCAM participates in several processes of tooth development.

Aging↗
PubMed1989

[Changes in the microvascular pattern of the periodontal ligament in an experimental tooth extrusion].

Forty eight adult cats were employed to investigate the serial changes of vascular patterns of the periodontal ligament on tooth extrusion. The right upper canines have been successively extruded (initial load 40 gr) with a open coil spring. The experimental periods were set on 1, 2, 3, 4 and 6 weeks respectively. On each experimental period, the microvascular casts of the periodontal ligament and alveolar bone around the experimental tooth were prepared for the scanning electron microscopy, utilizing the acrylic plastic injection method (Taniguchi and Ohta, et al. 1952 and 1955). And the serial sections of the surrounding tissues of the experimental tooth were made. In order to elucidate the mode of the tooth movement, the load of applied force and the distance of extrusion were measured. Results obtained were as follows: 1. The experimental tooth was extruded rapidly during first two weeks. The speed reduced gradually afterwards. 2. The new vascularization was seen around the apex first, then widely spread in the periodontal ligament. And the remarkable trabecula-shaped bone formation were observed around the venous networks of the root apex after two week period. 3. The tissue reactions after the tooth extrusion delayed in comparison with the movement of the tooth. 4. Although the tissue reactions of the root apex of the extruded tooth were originally similar to the one in the transverse tooth movement, slight differences were found in timing of the tissue change and shape of the capillary network. The findings of the tissue change showed that the light force was indicated in extrusion of the tooth. And the range of action of the force applied should be limited in orthodontic clinic.

Alveolar Process↗
PubMed2002

Accuracy of a new apex locator: an in vitro study.

AIM: The purpose of this study was to test in an in vitro model the accuracy of a Bingo 1020 electronic apex locator, to compare the results to those of a well known apex locator, Root ZX, as well as to those of the radiographic method of tooth length determination. METHODOLOGY: A total of 120 extracted teeth, preserved in Thymol solution and kept refrigerated, was used for the study. The experiment was performed on single-rooted teeth and on one-root canal, chosen randomly, in multirooted teeth. The teeth were randomly divided into 12 groups of 10 teeth each. After access preparation, the actual length (AL) was measured. The teeth were embedded in an alginate model specially developed for testing apex locators. Electronic tooth length measurements (EL) were carried out prior to root canal preparation using the two electronic apex locators (EAL) - Root ZX and Bingo 1020; three measurements were taken and an average computed. After the third measurement, the file was left in the root canal and a periapical radiograph was taken. The radiographic length (RL) was recorded by measuring the file length from the coronal reference point to the tip of the file. Each root canal was then prepared to a no. 40 K-file diameter using a standardized technique; saline was used for irrigation. Upon completion of the root canal preparation, EL measurements were taken by each EAL in dry conditions and with different irrigation solutions. Each measurement was repeated three times. The RL was recorded according to the last EL measurement. Results were subjected to statistical analysis. RESULTS: In all parameters tested, a significant statistical difference was found between Bingo 1020 and the Root ZX. Measurements obtained using the Bingo 1020 were consistently closer to the AL (0.08 mm) than those obtained using the Root ZX. Both EALs measured the tooth length with great accuracy and a positive correlation of 0.76 (P = 0.00) existed between the two devices. No significant difference was found between the two apex locators when measurements were taken with the different irrigants (P = 0.34) and the content of the root canal did not affect the accuracy of the measurements. Lengths obtained by calculations from the radiographs were longer than the AL as well as the length obtained by both EALs (P = 0.00). CONCLUSIONS: The Bingo 1020 proved to be as reliable as Root ZX and was user friendly. Under the experimental conditions, electronic measurements were more reliable than radiographs in the process of root length determination.

Analysis of Variance↗
PubMed1985

The pathogenesis of excessive wear in the permanent teeth of sheep.

The two central pairs of permanent incisor teeth (l1P, I2P) were compared post mortem in sheep from two flocks, one of which showed excessive wear. Sheep were usually killed in groups of six. Excessive wear occurred during the winter and spring after the eruption of l1P. When l1P erupted at an early age it was also subject to that season;s wear but when it erupted at a later age, it was subject to less wear according to the amount of time it was in apposition with the dental pad during the high wear season. A small amount of compensatory growth at the root of the tooth occurred in some sheep when cementum was deposited on the apex. Apparent eruption of the crown of the tooth was actually due to gum recession. Normal reparative dentine was laid down in the pulp cavity of the crown of the tooth in anticipation of wear, but where wear was excessive unstructured dentine was deposited. In two cases the rate of wear was so great that the reparative dentine could not keep up and infection was able to gain access to the pulp cavity. There was no evidence of difference in the rate of wear of the molar teeth between the two flocks.

Journal Article↗
PubMed1989

[Anatomical study on the root apex in the maxillary anterior teeth].

This study was undertaken to anatomically investigate the apical portion of root canal. Teeth used in this study were thirty maxillary central incisors, thirty maxillary lateral incisors and thirty maxillary cuspids extracted from patients between the ages of 11 and 73. All of the teeth had periodontal disease, but none had periapical disease. Resorption of the root surface could not be seen with the naked eye. The results obtained were as follows: 1. Deviations of the root apex and the apical foramen. Both of the root apex and apical foramen of the central incisors and cuspids were displaced distolabially from the tooth axis. Those of the lateral incisors were displaced distolingually from the tooth axis. The coincidence between the root apex and apical foramen was found in 16.7 per cent of both the central incisors and the cuspids, and in 6.7 per cent of the lateral incisors. 2. Diameters of the apical foramen and perpendicular distances between the root apex and apical foramen. The labiolingual diameters in the apical foramen of the central incisors, the lateral incisors and the cuspids were 0.504 mm, 0.452 mm and 0.425 mm respectively. Those diameters were larger than the mesiodistal diameters in the maxillary anterior teeth. Both the labiolingual and mesiodistal diameters in the central incisors were the largest. The perpendicular distances between the root apex and the apical foramen of the central incisors, lateral incisors and cuspids were 0.450 mm, 0.440 mm and 0.510 mm respectively. Those in the cuspids were the largest. The apical foramen in the cuspids was located slightly closer to the cervical side. 3. Diameters of the apical constriction and perpendicular distances between the root apex and apical constriction. The apical constriction of the root canal was located in either cementum or dentin. The labiolingual diameters of the root canal in the apical constriction of the central incisors, the lateral incisors and the cuspids were 0.425 mm, 0.369 mm and 0.425 mm respectively. The root canal labiolingual diameters in the maxillary anterior teeth was approximately 0.050 mm larger than mesiodistal diameters. The shapes of the root canal in the apical constriction were mostly the circular, oval and ovoid, while a few irregular shapes were observed. The perpendicular distances between the root apex and the apical constriction of the root canal in the central incisors, the lateral incisors and the cuspids were 0.863 mm, 0.825 mm and 1.010 mm respectively. 4. The stricture ratio of diameter between the apical foramen and the apical constriction of the root canal.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1999

Apical transportation revisited or 'where did the K-file go'?

CASE REPORT: This case report describes the outcome of a number of retreatments on a failed root filling in a maxillary first molar. The patient wanted all amalgams replaced by tooth-coloured Cerec restorations, including one in a symptomless maxillary molar. This tooth had a pulpotomy or a poorly done root-canal treatment 10 years earlier. The molar was root-canal retreated before placing the Cerec restoration and the palatal canal was filled 5 mm short of the radiographic apex. About 1 year later the patient presented with pain. Suspecting that a second mesiobuccal canal (MB-2) had not been located, a second non-surgical retreatment was instituted. MB-2 was not found and the palatal canal was retreated a third time, setting the working length 2 mm short of the radiographic apex. Because pain persisted palatally an apicectomy was performed and the tooth became symptomless. The resected palatal root apex was subsequently serially cross-sectioned, photographed and the canals analysed. Obvious apical transportation occurred during the cleaning and shaping procedures. Analyses of the canals showed that despite the retreatments, 11% of the canal cross-sectional area remained uncleaned although 7% of the root area was 'shaped'. Radiographically, the obturated palatal canal appeared reasonably well centred. However, this was disproved by the cross-sections, indicating that in this case, the clinician did not know where the K-Files had 'gone'. Apically, the obturated canal was certainly not within the natural canal. The pain located palatally was probably due to inadequate cleaning and shaping of the apical part of the root canal and its accessory canals.

Apicoectomy↗
PubMed2000

Prevalence and extent of long oval canals in the apical third.

OBJECTIVE: The aim of this study was to investigate the canal diameters in the apical roots of human teeth to determine prevalence and extent of long oval canals. STUDY DESIGN: This investigation was carried out on 180 extracted human teeth, 20 for each tooth group. Each root was horizontally sectioned at 1, 2, 3, 4, and 5 mm from the apex. Canal diameters were measured with a measuring microscope. RESULTS: In 293 (25%) of the 1181 cross sections investigated, a long oval canal (the long canal diameter was at least 2 times the short canal diameter) was identified. In some tooth groups, the percentage of long oval canals exceeded 50%. In most cases, the long diameter decreased apically; that is, the canal tended toward a rounder cross section. A wide range of diameters existed in all canals. CONCLUSION: Long oval canal is common in the apical 5 mm in human teeth. Many long and narrow oval canals would be impossible to instrument completely without perforating or significantly weakening the roots. Care should be taken in cleaning, shaping, and obturating these oval canals.

Adult↗
PubMed1999

External apical root resorption of posterior teeth in asthmatics after orthodontic treatment.

External apical root resorption is an undesirable sequela of orthodontic treatment, resulting in loss of tooth structure from the root apex. It has been proposed that systemic factors, such as the inflammatory mediators produced in asthma, may enter the periodontal ligament and act synergistically to enhance root resorption. The aim of this study was to determine if asthmatic patients exhibited a higher incidence or severity of external apical root resorption compared with healthy (no medical conditions) patients after fixed orthodontic treatment. Records were obtained from patients treated with fixed appliances; 99 were healthy and 44 had asthma. Using OPGs (panoral films), posterior external apical root resorption was measured on all first and second premolars, mesiobuccal and distobuccal roots of the upper first molars, and mesial and distal roots of the lower first molars, giving 4 measurements per quadrant. A 4-grade ordinal scale was used to determine the degree of external apical root resorption. Combined tooth analysis (adjusted for treatment time, appliance, and extractions) showed that asthmatics had significantly more external apical root resorption of posterior teeth after treatment compared with the healthy group (P =.0194). Tooth-by-tooth analysis (adjusted for treatment time, appliance, extractions, headgear, overbite, overjet, sex, and age at start of treatment) found the upper first molars were most susceptible to external apical root resorption. Although the incidence of external apical root resorption was elevated in the asthma group, both asthmatics and healthy patients exhibited similar amounts of grade 2 (moderate) and grade 3 (severe) resorption.

Adult↗
PubMed1976

The rodent incisor tooth proliferon.

The rodent incisor tooth is the site of five cell populations proliferating in harmony: amelocytes, odontocytes, pulp cells, endothelial cells and the periodontal ligament. Their proliferating regions are located in the apex tip, where the various cells originate. Cells displaced from the tooth origin at the apex toward the periphery, mature to perform their specified function. The proliferative events in the tooth are summarized in a conceptual model of the incisor proliferon. The proliferon is an oriented structure with an origin and periphery. It consists of four basic elements: parenchyma, connective tissue, blood vessels and nerve fibres, all interacting continuously. All four are indispensable in the definition of the proliferon.

Ameloblasts↗
PubMed2003

An in vivo comparison of two frequency-based electronic apex locators.

The purpose of this study was to compare the accuracy of a two-frequency (Root ZX) and a five-frequency (Endo Analyzer Model 8005) electronic apex locator under clinical conditions. Thirty-two teeth planned for extraction were used. The coronal portion of each canal was flared using Gates Glidden drills and Orifice Shapers. The canals were irrigated with 2.6% sodium hypochlorite. A K-type file was used to determine a separate working length in each canal using the electronic apex locators. The teeth were extracted and the apical 4 mm of each root canal was exposed along the long axis of the tooth. Photographic slides of each canal were projected and the file position in relation to the minor diameter was determined by two investigators. The mean distance between the electronic apex locator working length and minor diameter was 1.03 mm for the Endo Analyzer and 0.19 mm for the Root ZX. A paired sample t test showed that the Endo Analyzer had significantly longer readings beyond the minor diameter than the Root ZX (p < 0.0001). The ability to locate the minor diameter (+/- 0.5 mm) was 90.7% for the Root ZX and 34.4% for the Endo Analyzer Model 8005.

Adult↗
PubMed1994

Root perforations. A review of literature.

Root perforations that result in a communication of the root space with the periodontal tissues occasionally occur during endodontic procedures. They may be induced iatrogenically, by resorptive process, or by caries. Identification of root perforations is possible by direct observation of bleeding, indirect bleeding assessment using a paper point, radiography, and an apex locator. Prognosis of a tooth with root perforation depends on the time lapsed before obturation of the perforation, location and size of the lesion, and the sealability of the repair material. Perforation defects may be repaired by nonsurgical or surgical techniques. A review of causes, diagnosis, prognosis, and management of root perforations provides information for avoiding, detecting, and treating of such defects.

Apicoectomy↗
PubMed1994

Low level laser therapy for dentinal tooth hypersensitivity.

A comparative double blind study testing low level laser therapy (Gallium/Aluminium/Arsenide laser [GaAlAs]) against placebo was carried out in the management of dentinal tooth hypersensitivity. Subjects demonstrating dentinal hypersensitivity and complying with strict selection criteria were randomly assigned to an active and placebo group. Low level laser therapy was applied for one minute to both the apex and cervical area of the tooth; and reapplied at one week, two-week and eight-week intervals. Dentinal hypersensitivity was rated at each visit. There were 28 subjects in the placebo group and 22 and 21 subjects, respectively, in the tactile sensitivity and thermal sensitivity groups. Comparisons between the groups were conducted using independent groups t-test. In both the tactile and thermal sensitivity groups differences between the active and placebo groups were significant from the first week and increased further in the second and eighth weeks. The mean value of thermal sensitivity decreased 67 per cent (p < 0.001) compared with placebo (17 per cent) and tactile sensitivity decreased 65 per cent (p = .002) compared with placebo (21 per cent) at eight weeks. Results demonstrate that the GaAlAs laser is an effective method for the treatment of both thermal and tactile dentinal hypersensitivity. There were no reported adverse reactions or instances of oral irritation.

Adolescent↗