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At least 19 recordsLinked to original sources
PubMed1995

[Prospective comparative randomized study of tooth apex resection and orthograde root filling with Guttapercha and titanium pins].

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.

Adult↗
PubMed1998

Calculus-like deposit at apex of tooth with refractory apical periodontitis.

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.

Chronic Disease↗
PubMed1991

Distribution and morphological characteristics of axons in the periodontal ligament of cat canine teeth and the changes observed after reinnervation.

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.

Animals↗
PubMed2004

Photoelastic study of the effects of occlusal surface morphology on tooth apical stress from vertical bite forces.

The aim of the study was to determine how the morphology of occlusal surfaces might affect occlusal loading that is transferred to the tooth apex. Photoelastic methods were used to assess apical stress generated by seven variations of occlusions. A test assembly with a 2 kg weight was applied to teeth to create a vertical load. By analyzing the direction and magnitude of the apical principle stress under the polar light that was measured at the apexes of mandibular teeth, the occlusal loading position of each tooth and its direction was obtained based on general mechanical principles. It was found distal incline planes (or slopes) of cusps and lingual incline planes (or slope) of buccal cusps of mandibular posterior teeth carried the greatest occlusal load in normal occlusion. In the other six variations of occlusion presented in this study, the principle apical stresses changed more or less as a result of the different occlusal contact relationships. The magnitude of principle apical stress increased considerably in the flat surface occlusion because of the lack of distribution of occlusion loading by the smooth dentition surface. It is concluded the occlusal surface morphology has a significant effect on the direction and magnitude of apical stress. To establish a suitable relationship of occlusion that can conduct favorable occlusal loading physiologically is very important.

Bite Force↗
PubMed1999

Long-term radiographic and histological observations of endodontically treated teeth.

Endodontic therapy was performed on 14 teeth in juveniles with inflamed or necrotic pulps. The patients were recalled at 6-month intervals for radiological and clinical examinations. After 1 yr, periapical surgery was performed on six teeth. After 18 months, 5 more patients were subjected to periapical surgery and, after 2 1/2 years, 3 more patients had periapical surgery. A small block section containing the root tip and surrounding tissues was removed from all of the patients. Radiographs showed reductions in size, but not elimination, of periapical lesions. Histological examinations revealed that most root canals were overfilled. Inflammation persisted around zinc oxide-eugenol particles beyond the tooth apexes. In addition, gutta-percha overfilling enhanced the proliferation of cell rests of Malassez. In some cases, dentin filings were found at and beyond the tooth apexes. The formation of new hard tissue was stimulated by the presence of dentin chips.

Extravasation of Diagnostic and Therapeutic Materi↗
PubMed1987

Structural changes in the dental and periodontal tissues of the rat incisor following application of orthodontic loads.

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.

Alveolar Process↗
PubMed2001

Ultrastructural changes in postcapillary-sized venule morphology in aged mouse periodontal ligament.

The aim of this study was to compare the postcapillary-sized venule (PCV) morphology of four young ALCA mice (35 days) and four colony-related aged mice (365 days) using the transmission electron microscope (TEM). Right and left mandibular first molar mesial roots with associated periodontal ligament (PDL) and bony socket, were used for TEM assessment. Five PCV profiles were selected at each 160 microm interval, from the alveolar crest to the tooth apex. PCV profile dimensions were measured on standardised micrographs magnified x2900. Age affects were tested using multiple regression analysis. The number of PCV profiles in the tooth third of the PDL was higher in aged mice (p < 0.01) and comprised predominantly apericytic vessels (p < 0.001). The number of PCV profiles increased significantly (p < 0.001) in aged mice in the PDL middle circumferential third halfway down the molar root. Age had no significant affect on PCV diameter. Aged PDL permeability studies are needed to investigate whether the changes in aged PCV profile number are associated with functional modification of the PDL microvasculature.

Aging↗