Epithelial attachment at diseased human tooth-apex.
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The prospective randomised study on the root apex resections with orthograde root filling comparing Guttapercha with Titan pins encompasses 500 patients with 633 operations on all front teeth and premolars. The patients were divided into three preoperative stages so that for this broadly defined diagnoses comparable collectives could be built. After an average postoperative interval of 21 months, 258 patients with 298 resected teeth could be evaluated. From these, 188 root apex resections had been treated with Guttapercha and 110 with Titan pins. 73.5% of the root apex resections were successful, whereby the group treated with Guttapercha was more successful by 7%. The comparatively high failure rate of 26.5% is attributable to the broadly defined diagnosis and the long follow-up period.
It is generally accepted that bacteria in or outside the root canal are the reason for apical periodontitis and endodontic failures. This case report presents a 60-year-old woman with a periapical lesion and a fistulous tract which did not respond to conventional root canal treatment. During periapical surgery, granulomatous tissue was removed and a calculus-like deposit was observed on the root surface. A radicular cyst was diagnosed. Nine months after this calculus-like deposit had been removed and the cyst enucleated, complete recovery of the bone had occurred. It is suggested that the presence of the calculus-like deposit at the apex of the tooth or its effects may in part have delayed the healing of the periapical inflammation in spite of apparently adequate endodontic treatment.
The distribution and morphological characteristics of myelinated and non-myelinated axons innervating the lower canine periodontal ligament (PDL) in adult cats have been analysed. After perfusion fixation and decalcification, the teeth were slit transversely, divided into segments, and embedded in plastic. Ultrathin sections of each segment were examined in the electron microscope and used to reconstruct the whole PDL at 1, 4, 7, and 9 mm from the tooth apex. One millimeter from the tooth apex there were a mean of 920 myelinated axons and 1,415 non-myelinated axons. The numbers of axons declined toward the tooth crown. Bundles of myelinated and small non-myelinated axons lay adjacent to the blood vessels midway between the bone and cementum. Isolated myelinated axons appeared to have split away from these main nerve bundles and entered the avascular zone of the ligament, where they lost their myelin sheaths to become large non-myelinated axons rich in mitochondria. These non-myelinated axons sometimes appeared to be linked to collagen fibres and were thought to be the mechanoreceptor terminals. Twelve weeks after sectioning and inferior alveolar nerve, the total number of axons innervating the periodontal ligament was 50% of that found in the contralateral controls. The large non-myelinated axons had smaller mean diameters and contained fewer mitochondria, a change which may be consistent with a reduction in mechanoreceptor excitability.
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The present study deals with the morphometric changes in the loaded rat incisor and its supporting structures 3 months after load removal. The material examined was limited to that part of the tooth that is located between 8 and 20 mm from the tooth apex. Of the ten albino rats in whom laterointrusive loads (19 +/- 0.6 g) were applied to the lower left incisor for a period of 2 weeks, the rate of tooth eruption returned to normal in four animals (group A); in six rats, eruption remained grossly impaired (group B). These two groups were compared with a control group of four rats in whom the incisors were allowed to erupt normally during the 3 months of the experiment. The left mandibles were dissected and fixed; the incisors were demineralized, embedded in paraplast, and cut into transverse serial sections of 6 micron, which were used to produce a three-dimensional reconstruction of all tissue components by means of computerized histomorphometry. The parameters of pulp and dentin, and the total tooth size and shape in group A were similar to those of the control group. In group B, pulp and dentin were changed significantly, tooth size increased, and the oval shape was altered into a more rounded contour, together with a significant enlargement of the socket. Although the total PDL volumes remained similar in all three groups, the tooth/socket relation, as expressed by PDL width and PDL area at the different tooth sides and at varying distances from tooth apex, diverged from normal significantly in all teeth that had been subjected to loading.
OBJECTIVE: To confirm that compensatory eruption (supereruption) of teeth past a stable periodontium occurs in response to severe occlusal attrition. DESIGN: Regression analysis study from radiographs and direct measurements. SETTING: Archaeological material at the University of Aberdeen. SUBJECTS: 47 individuals > 21 years old and dating from Late Mediaeval times (1300-1600 AD). MAIN OUTCOME MEASURES: Occlusal attrition was recorded on the first permanent mandibular molars. Measurements on radiographs of the teeth from the fixed point of the inferior dental canal were taken to the occlusal surface, the alveolar crest and the tooth apex. Regression analysis was undertaken between these variables and related to attrition (age). RESULTS: Continuous eruption of the permanent human dentition past a stable periodontium does occur in response to tooth height lost by wear, despite the fact that supereruption may lead to the eventual self destruction of the dentition. This mechanism was primarily responsible for the early loss (at 40-45 years of age) of dentitions in Mediaeval times. CONCLUSIONS: Stability of occlusal height appears to be an important function of the dentition and if triggered by severe wear will lead to increasing root exposure and eventual exfoliation of the teeth. It is important not to confuse bone loss due to periodontitis with root exposure due to supereruption of the teeth.
Image quality is limited by the information capacity of the image-forming system and can be computed from three parameters: contrast, resolution, and noise. These parameters can be combined to yield a single measure which determines the maximum amount of information obtainable from any x-ray system and is called the noise-equivalent number of quanta (NEQ) per unit area. The effects of image quality, expressed as noise-equivalent number of quanta (NEQ) per unit area, on the radiographic performance by dentists reading the position of an endodontic file in a root canal were studied. Three different speed films were used in conjunction with a fixed screen. NEQ values ranged between 0.64 x 10(4) and 14.3 x 10(4) per square millimeter. Components of variance associated with the position of the tooth apex and the tip of an endodontic file in a root canal were compared for the effect of different NEQs and observers. Results show that the standard deviation in locating a file tip and tooth apex may be a linear function of log NEQ. The estimated standard deviation associated with changes in NEQ was found to be relatively small compared to that observed among dentists. These findings indicate that a significant reduction in exposure would have a relatively small effect on the precision of endodontic distance measurements.
Cutaneous manifestations of a periradicular inflammation are now uncommon. In most cases the periradicular infection results in the development of an apical granuloma. If there is proliferation of resting epithelial cells in this granuloma a cyst will develop, the so-called radicular cyst. A rare form of periradicular inflammation is the so-called chronisch granulierende Entzündung nach Partsch [Partsch's chronic granulomatous inflammation]. In this case the granulation tissue spreads through the bone and results in a cutaneous odontogenic sinus. We report on a female patient in whom complete healing was obtained by removal of the periradicular process and excision of the sinus tract.
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