Structural and ultra-structural features of the first mandibular molars of young rats submitted to pre and postnatal protein deficiencies.

The effects of protein malnutrition, both in utero and prior to weaning, on formation of the first mandibular molars were evaluated by phase-contrast and electron microscopy in rats. The nourished group (GI) received a diet that included 20% casein, while the malnourished group (GII) received 5% casein. The first mandibular molars from GII exhibited low density of cells and odontoblasts, which lacked regular organization compared with molars from GI. In addition, a difference in collagen type was observed between the groups, with a prevalence of Type III collagen fibers detected in the dentin, periodontal ligament, and alveolar bone of GII, and a prevalence of Type I collagen fibers in GI. Finally, examination of surface area in molar sagittal sections indicated 30% less dentin in GII, compared with GI. Our results suggest that structural and ultra-structural features of the dentin-pulp complex and periodontal components of rat molars are affected by protein deficiency.

Contribuiçäo ao estudo da anatomia do sistema de canais radiculares de caninos inferiores utilizando-se de cortes macroscópicos e da diafanizaçäo / Anatomy study of root system of lower canines using macroscopic cuts and clarifying technique

A anatomia dos canais radiculares tem sido tema de estudos desde 1942 e mesmo com as diversas observaçöes descritas por vários autores, permaneceu-se dúvidas a respeito dos aspectos morfológicos internos de vários grupos de dentes. O presente trabalho utilizou-se de 103 (cento e três) caninos interiores extraídos, onde se analisou os aspectos macroscópicos da cavidade pulpar, utilizando-se de cortes sagital, frontal e transversais, assim como da diafanizaçäo. Notamos que, em 100 po cento dos espécimes haviam uma raiz e um único canal radicular, sendo que em 83 por cento das amostras evidenciou-se permeabilidade dentinária. Os canais secundários foram verificados em 47 por cento dos dentes, assim com 3 por cento de canais laterais, 1 por cento canal acessório e 15 por cento co delta apical. fator importante que observamos também foi que, em 42 dos espécimes o forame apical coincidia-se com o ápice radicular; 23 por cento, abria-se para vestibular, 8 por cento, para distal; 8 por cento, para mesial e 4 por cento para lingual

The structure of the bilaminar zone in the human temporomandibular joint: a light and scanning electron microscopy study in young and elderly subjects.

The bilaminar zone (BZ) in the human temporomandibular joint (TMJ) of toothed adults (GI) and toothless, elderly humans (GII) were analysed using light and scanning electron microscopy (SEM). In both groups the BZ consists of an upper and a lower stratum of connective tissue separated by a vascularized middle region. The superior stratum contains bundles of collagen fibres disposed in different directions. The fibres are fairly thick and transversely oriented immediately posterior to the TMJ disc. The initial part of the inferior stratum contains curved bundles of collagen fibres oriented anterio-posteriorly. From the middle to the posterior part of the inferior stratum, the fibres are right-aligned in GI and clearly sinuous in nature in GII. In both groups, the middle and posterior portions of the middle region are distinguished by the presence of vessels and vascular spaces. Loosely arranged connective and adipose tissues are also evident. The vascular spaces are wider in GII than in GI. The predominance of type I collagen fibres is clear in all regions of the BZ in both groups. The elastic fibres lie parallel to the collagen fibres in both groups and they are thicker and more abundant in GI, apparently decreasing in GII.

The structure of the bilaminar zone in the human temporomandibular joint: a light and scanning electron microscopy study in young and elderly subjects / Estrutura da zona bilaminar na articulação temporomandibular humana: um estudo leve e microscopia eletrônica de varredura e assuntos antigos

The bilaminar zone (BZ) in the human temporomandibular joint (TMJ) of toothed adults (GI) and toothless, elderly humans (GII) were analysed using light and scanning electron microscopy (SEM). In both groups the BZ consists of an upper and a lower stratum of connective tissue separated by a vascularized middle region. The superior stratum contains bundles of collagem fibres disposed in diferent directions. The fibres are fairly thick and transversely oriented immediately posterior to the TMJ disc. The initial part of the inferior stratum contains curved bundles of collagem fibres oriented anterio-posteriorly. From the middle to the posterior part of the inferior stratum, the fibres are right-aligned in GI and clearly sinuous in nature in GII. In both groups, the middle and posterior portions of the middle region are distinguished by the presence of vessels and vascular spaces. Loosely arranged conective and adipose tissues are also evident. The vascular spaces are wider in GII than in GI. The predominance of type I collagen fibres is clear in all regions of the BZ in both groups. The elastic fibres lie parallel to the collagen fibres in both groups and they are thicker and more abundant in GI, apparently decreasing in GII

The arrangement of the trabecular bone in the vestibular surface of the human fetus mandible. A scanning electron microscopy study.

The characteristics of trabecular bone in human fetuses at seven to nine months of intra-uterine life were studied in the vestibular surface of the mental and body portions of the mandible. In the mental portion, many circular trabeculae joined by "bridges" were observed in the alveolar region (AR). In the 8-month old fetus are trabeculae with tortuous disposition in the medium region (MR). Oblique trabeculae with superior and inferior dispositions defining a triangular area (future mental fossae) are verified in 9-month old fetuses. Trabeculae circularly disposed and vascular foramina are present close to the apex of this area. In the basilar region (BR) some trabeculae obliquely oriented are observed disposed near to the mandibular symphysis. The longitudinal bundles of collagen fibers assume an antero-posterior direction. At 9-month age the vascular foramina range from 6 to 20 microns and the osteocyte lacunae ranging from 1 to 4 microns diameter, are present in mandibles from all ages examined. In the body portion the presence of circular trabeculae joined by "bridges" is the main characteristic of the AR. In the MR most of the trabeculae are circular and the longitudinal trabeculae of this region assume an antero-posterior direction. The laminar, antero-posterior and juxtaposed trabeculae lying parallel to mandible base are a characteristic of the BR. The bundles of collagen fibers exhibit the same pattern of the trabeculae. The vascular foramina of the BR are smaller than that of the precedent regions. In the body portion of the mandible from all ages examined the osteocyte lacunae range from 1 to 4 microns in diameter.

The arrangement of the trabecular bone in the vestibular surface of the human fetus mandible. I. A scanning electron microscopy study (1).

The characteristics of trabecular bone in human fetuses at three to six months intra-uterine life were studied in the vestibular surface of the mental and body portions of the mandible. Rounded trabeculae disposed vertically were observed in the alveolar region of the mental portion until 3 months of age. Bundles of collagen fibers were present longitudinally in the alveolar region of the mandibular body: laminar and longitudinal trabeculae lying parallel to the mandible base were seen in the basilar region. In 4 to 6-month old fetuses rounded trabeculae were observed in the alveolar region of the mental portion; in the medium region, the trabeculae were oblique while in the basilar region they were longitudinal and parallel to mandible base. In the alveolar region of the mandibular body, trabeculae with a rounded aspect were seen: in the medium region, they were straight, oblique and longitudinal to the mandible ramus: in the basilar region, the trabeculae were longitudinal and parallel to mandible base. The alveolar foramina exhibit differing diameters and shapes in the mental and body portions: thick bundles of collagen fibers and osteocyte lacunae of varying diameters were present in the bone surface.

Light and scanning electron microscopic studies of the effects of CO2 laser on the palatine mucosa of rats.

In order to verify the effects of CO2 laser on the palatine mucosa of rats, 15 animals were utilized. The animals were anaesthetized with thionembutal by intra-peritoneal injection and the palatine mucosa of each animal was irradiated with a single pulse of 10 W. The results showed that immediately after the irradiation of CO2 laser, the formation of small cavities is observed. The wound healing post operationem is gradually in 1 week. The region is totally occupied by neoformed connective tissue and epithelial cells. Numerous polymorphonuclear cells and fibroblasts may be seen between the neoformed collagen fibres.

[Anatomical variations of the clinoid process of the human sphenoid bone]. / Variação anatômica do processo clinóide do osso esfenóide humano.

The authors analysed 270 human adult skulls of both sexes, in order to demonstrate the fusion of clinoid process of sphenoid. It was verified only 38 cases under several shapes. According to our results obtained, may be concluded: a) the fusion between the anterior and medium clinoid processes occurred in 17 cases (6.27%), being that in 11 cases (4.05%) bilaterally; b) between the medium and posterior clinoid processes occurred in six cases (2.22%); c) between the anterior and posterior clinoid processes occurred bilaterally in six cases (2.22%); d) between the three processes occurred in nine cases (3.04%).