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PubMedDate not supplied

[Study of the possibility of utilizing the transpired mositure condensate from sweet potato for growing plants in biological life support systems].

The effect of nonpurified condensate obtained during prolonged cultivation of batata in a sealed chamber upon batata cuttings and seedlings of garden cress, radish and Chinese cabbage was studied. It was shown that nonpurified condensate produced an inhibitory effect on the formation of roots in batata cuttings and on the growth of previously developed roots of batata cuttings and seedlings. The studies which used a chemical model of 3,4-dihydroxy phenylalanine indicated that the condensate contained biologically active substance of organic origin. However, only experiments with the real continuous culture of batata, using real dilutions of the condensate that depend on the size of the greenhouse and the amount of the nutrient solution would clarify wheather condensate of transpiration water of batata plants can be repeatedly utilized in life support systems.

Ecological Systems, Closed↗
PubMed1990

A long-term study of 370 autotransplanted premolars. Part II. Tooth survival and pulp healing subsequent to transplantation.

The purpose of the present investigation was to determine the long-term prognosis of autotransplanted premolars with respect to tooth survival and pulpal healing. The material consisted of 195 patients aged 7 to 35 years, with a total of 370 autotransplanted premolars with observation period ranged from 1 to 13 years. Teeth transplanted with incomplete and complete root formation showed 95 per cent and 98 per cent long-term survival respectively: Pulp healing as evaluated by sensibility testing and radiographic signs of partial pulp canal obliteration was usually verified 6 months after transplantation. The frequency of pulpal healing (versus pulp necrosis), appeared to be closely related to stage of root development at time of transplantation. Teeth transplanted with incomplete and complete root formation showed 96 per cent and 15 per cent pulp healing respectively. Another and associated factor which could equally well predict pulpal healing was the diameter of the apical foramen of the graft. Finally, in teeth with completed root formation, the use of bursa with internal cooling and no extra-alveolar storage prior to transplantation seemed to increase the chance for pulpal healing. The present study indicates, that the size of the apical foramen and possibly the avoidance of bacterial contamination during the surgical procedure are explanatory factors for pulpal healing.

Adolescent↗
PubMed1992

Mineral-associated adhesion proteins are linked to root formation.

There is a general agreement that the extracellular environment plays a critical role in controlling cell behavior. Thus, significant research efforts have focused on understanding the effects of extracellular matrix proteins on cell function. In particular we have focused on determining the role of adhesion proteins in the regulation of root formation. Using an OPN antibody, 2arN (generously provided by Drs Craig and Denhardt), the expression of OPN during root formation was determined. OPN (osteopontin) is a bone-associated adhesion protein. OPN was expressed in the dental follicle region of molars obtained from 3 day old CD-1 mice, but was not expressed in the odontoblast layer. In contrast by day 8, positive staining was noted in the odontoblast layer, as well as in the area of Hertwig's epithelial root sheath. However, at this same time point no positive labeling for 2arN was observed in the enamel organ or in the dental papillae cells. By day 15 positive staining for OPN was seen in the area of the periodontal ligament, as well as the region of primary deposition of extracellular matrix onto dentin. Also determined was the ability of fibronectin, OPN and dentin sialoprotein (DSP) to promote the attachment of dental ectomesenchymal cells, in vitro. Interestingly, these cells attached remarkable well on bacteriological dishes (control) in the absence of an adhesion protein. DSP did not increase cell attachment beyond that observed for control cells. In contrast, both fibronectin and OPN enhanced cell attachment. These studies, while preliminary indicate that OPN is expressed in a unique fashion during root development, thus suggesting a regulatory role for such adhesion proteins during root formation.

Animals↗
PubMed1991

The development and structure of principal fibers and cellular cementum in rat molars.

The principal fibers and cellular cementum were examined in various developmental stages in rat molars by light and electron microscopy, and their development and structure were studied. The principal fibers increased in thickness with root development. At any given stage, the principal fibers consisted of small fiber bundles on the cementum surface and showed a branching structure. Sharpey's fibers also showed a similar branching structure and increased in thickness, as traced superficially in the cementum. It was suggested that the principal fibers increased in thickness by means of the aggregation of fiber bundles. The development of cellular cementum was divided into two (early and late) phases on the basis of the fiber arrangement. The early cementum was believed to contain a few Sharpey's fibers and many randomly arranged intrinsic fibers. The late cementum contained thicker Sharpey's fibers with branches and the intrinsic fibers which appeared to encircle Sharpey's fibers and/or meander among them.

Animals↗
PubMed1985

Dental development in precocious puberty.

One hundred and one children with precocious puberty were given an oral examination. Dental root development was assessed using panoramic radiographs. All mandibular canines, pre-molars, and molars which could be visualized without apparent distortion were included. The patients were grouped for analysis according to the etiology of their precocity, e.g., McCune-Albright syndrome, familial male, congenital adrenal hyperplasia, central nervous system lesions, and idiopathic precocious puberty. Dental development was significantly retarded relative to their chronological age in patients with idiopathic precocious puberty. However, no significant abnormal dental development was detected in any of the other groups. Individual oral-facial growth and development remain the primary considerations for timing orthodontic treatment.

Age Determination by Skeleton↗
PubMed1991

Establishment of acellular extrinsic fiber cementum on human teeth. A light- and electron-microscopic study.

The present study describes for the first time the development of early acellular extrinsic fiber cementum (AEFC) until its establishment on human teeth. Precisely selected premolars with roots developed to 50%-100% of their final length were prefixed in Karnovsky's fixative and most of them were decalcified in EDTA. Their roots were subdivided into about 10 blocks each, cut from the mesial and distal root surfaces. Following osmication, these blocks were embedded in Epon and sectioned for light- and transmission electron microscopy. Some blocks were cut non-demineralized. From semithin stained sections, the density of the collagenous fiber fringe protruding from the root surface was measured by using the Videoplan-system. After initiation of this fiber fringe and its attachment to the dentinal root surface followed by mineralization, the fringe gradually increased in length and subsequently became mineralized. Fringe elongation and the advancement of the mineralization front appeared to progress proportionally. Thus, in all stages of AEFC development, a short fiber fringe covered the mineralized AEFC. Its density remained constant, irrespective of AEFC thickness. The latter gradually increased and reached an early maximum of 15-20 microns in the cervical region. At this stage, the AEFC fringe appeared to fuse with the future dentogingival or other collagen fibers of the tooth supporting apparatus. Mineralization of the fringe commenced with isolated, spherical or globular centers, which later fused with the mineralization front and became incorporated in AEFC.

Adolescent↗
PubMed1991

Acute pulpal-alveolar cellulitis syndrome V. Apical closure of immature teeth by infection control: case report and a possible microbial-immunologic etiology. Part 1.

Das with Matusow and Goodall previously noted the rapid clinical apexogenesis of nonvital immature permanent teeth that are involved with an acute endodontic cellulitis. This apexogenesis was achieved by control of infection and by nonspecific intracanal medication without the use of calcium hydroxide. The case report confirms the clinical observations. The experimental canine endodontic cellulitis in a Cebus primate was induced as an immunologic pulp infection with a facultative Streptococcus species. The noted epithelial proliferation and organization into lacelike strands and bilaminar loops, similar to Hertwig's epithelial root sheath in root development, appear to be immunologic and genetic in origin, with an acceleration of the root maturation process.

Animals↗
PubMed1988

Evaluation of the effects of F in acidified gelatin gel on root surface lesion development in vitro.

Oral exposed, natural root surfaces of extracted human teeth were subjected to artificial lesion formation in gels of dialyzed gelatin that contained 75 mM lactic and 25 mM acetic acid and 1, 3, 10, 32, 100, 320, 550, or 1,000 mg F/l at pH 4.3-4.4 and at 36 degrees C. Ca and PO4 demineralization per square millimeter exposed surface and lesion depth decreased with increased F concentrations, except for the levels above 320 mg/l. Quantitative microradiographic image analyses showed that the mean percent mineral content of the entire lesions relative to the adjacent sound tissue was constant at about 64% for the F levels less than 320 mg/l. F above 3 mg/l changed the mineral density profile of the lesions by eliminating subsurface lamination. This showed that sufficient F incorporated at the site of demineralization prevented lesion progression and that the best effect would be obtained for F levels between 100 and 320 mg/l. Higher levels of F may also prove to be beneficial by providing labile F from CaF2 formed in the root surface.

Acids↗
PubMed1988

Oral condition in children treated with bone marrow transplantation.

Oral health was studied in 49 children below 12 years of age treated with bone marrow transplantation (BMT). Dental treatment prior to BMT was required in 41% of the children. Ulceration of the mucous membranes in the mouth was observed in 37% of the patients during treatment. Those given methotrexate as prophylaxis against graft-versus-host disease (GVHD) exhibited oral ulcerations more frequently (p less than 0.05) than those given cyclosporin. One year after BMT all patients with a clinical chronic GVHD exhibited changes in the oral mucosa. During the first year after BMT 31% of the children developed carious lesions. Children treated with 10 Gy total body irradiation (TBI) had a significantly (p less than 0.05) reduced salivary secretion rate. Dental development was severely affected in children treated with TBI. These disturbances consisted of arrested root development, enamel hypoplasias and microdontia.

Bone Marrow Transplantation↗
PubMed1992

Initial formation of cellular intrinsic fiber cementum in developing human teeth. A light- and electron-microscopic study.

The present study describes the formative process of the initiation of cellular intrinsic fiber cementum (CIFC) in still growing human teeth. From 29 premolars and molars with incomplete roots developed to 60-90% of their final length, 8 premolars (with roots formed to three quarters of their final length) were selected for electron-microscopic investigation. All teeth were clinically intact and prefixed in Karnovsky's fixative immediately after extraction. Most of them were decalcified in ethylene diaminetetraacetic acid (EDTA), and the apical part of the roots was divided axially into mesial and distal portions that were subdivided in about 5 slices each. Following osmication and embedding in Epon, these blocks were cut for light- and electron-microscopic examination. In addition, 5 teeth with incomplete roots were freed from organic material and processed for scanning electron microscopy. It was found that CIFC-initiation commenced very close to the advancing root edge and resulted in a rapid cementum thickening. Thereafter, appositional growth continued on the already established cementum surface. Large, basophilic and rough endoplasmic reticulum-rich cementoblasts, some of which became cementocytes, were responsible for both fast and slow CIFC-formation. The CIFC-matrix was free of Sharpey's fibers and composed of more or less organized intrinsic collagen fibrils, in part fibril bundles, that ran roughly parallel to the root surface. Initially, the cementum fibrils intermingled with those of the dentinal collagen fibrils, which were not yet mineralized. This boundary subsequently underwent calcification. The development of collagen fibril bundles and their extracellular arrangement were associated with cytoplasmic processes probably involved in fibril formation and fibril assembly. Many cementoblasts contained intracytoplasmic, membrane-bounded collagen fibrils, which probably were related to fibril formation rather than degradation.

Adolescent↗
PubMed1992

Ehlers Danlos syndrome type I with novel dental features.

The clinical, radiographic and histologic findings are described in two cases of Ehlers Danlos Syndrome Type I with novel dental features. Defective dentinogenesis principally affecting the mandibular incisors result in aplasia or hypoplasia of root development predisposing to localized periodontal disease. A striking radiographic appearance with a bulbous enlargement of the roots together with pulp stones is seen in other teeth. 'Giant channels' and vascular inclusions resembling 'intermediate cementum' are prominent within this area. No evidence of Type III procollagen or collagen was detected with indirect immunofluorescence. It is suggested that an inherited collagen abnormality in a component common to dentin, skin, ligament and tendon probably explains both EDS I and the dentin dysplasia.

Adult↗
PubMed1992

Growth of acellular extrinsic fiber cementum (AEFC) and density of inserting fibers in human premolars of adolescents.

The present study describes for the first time the changes of both AEFC thickness and the numerical density of collagen fibers inserting into AEFC at specified levels and sites of human premolars at different stages of development. The investigation was based on 45 premolars (25 maxillary, 20 mandibular; 25 first and 20 second), extracted from adolescents and young adults. All teeth were free of disease and presented with roots developed from 30-100% of their final length. They were prefixed in Karnovsky's fixative, decalcified in EDTA and subdivided into about 14 slices each, cut from mesial and distal root surfaces, vertical to and along the root axis. The slices were postfixed in OsO4, embedded in Epon and cut for light-microscopic study. AEFC thickness (4086 measurements) and the density of the collagenous fiber fringe (454 counts) inserting in AEFC were measured at 1, 3, 5 and 7 mm apical to the cementoenamel junction. The data obtained showed: AEFC thickness increased with age and varied between 0 and 57.5 microns. Between 9 and 17 years, cervical AEFC thickness increased in maxillary first premolars from an average of 5 to 30 microns, and in mandibular second premolars from 6 to 20 microns, i.e., AEFC grew at approximately the same rate as later in life. Depending on the differences in tooth development, AEFC on maxillary first premolars became thicker than that on mandibular second premolars. Due to the corono-apically decreasing gradient of AEFC development, its increase in mid-root regions lagged behind that in cervical regions of all teeth in people younger than about 14 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Autotransplantation of teeth].

This article gives a review of autotransplantation of teeth. From being a method of rather poor prognosis, autotransplantation has developed to be a safe treatment procedure. Scientific criteria for selecting patients, donor teeth, surgical procedures and postoperative care has contributed to this. The surgical procedure and the endodontic treatment are discussed. The degree of root development is of importance. Complications may be extern root resorption and ankylosis because of damage to the periodontium.

Humans↗
PubMed1990

Evidence for rapid multipolar and slow unipolar production of human cellular and acellular cementum matrix with intrinsic fibers.

The genesis of root cementum has been studied infrequently in animal models, e.g., in mice, rats and dogs, but rarely in the human. The present study was based on 8 premolars (4 maxillary and 4 mandibular, 7 first and 1 second) selected from a large collection of freshly extracted human teeth. All teeth were free of disease and presented with roots developed to about 50-80% of their length. After decalcification in EDTA, the apical half of the roots was divided axially into mesial and distal portions. The latter were subdivided into 4 slices cut in the corono-apical direction. These slices were Epon-embedded and cut for examination in the light- and transmission electron microscope. It was found that 2 basically different modes of cementum matrix production occurred at or near the advancing root edge. These 2 modes, i.e., the multipolar versus unipolar matrix production, resulted in either cellular (CIFC) or acellular intrinsic fibre cementum (AIFC). Both varieties did not contain fibres of Sharpey and were restricted to regions of the root usually covered with cellular mixed stratified cementum (CMSC). By comparison with recently published data on the rate of cementum apposition, it is suggested that the multipolar mode is a rapid form, whereas the unipolar mode is a slow-rate form of producing intrinsic fibre cementum.

Adolescent↗
PubMed1978

The influence of alachlor, trifluralin, and diazinon on the development of endogenous mycorrhizae in soybeans.

Preplant incorporated treatments of 2 and 4 kg/ha of trifluralin and diazinon had no significant effect on growth, P accumulation or root colonization by mycorrhizal fungi in soybeans planted in an Andover clay loam. At 4 kg/ha, alachlor and trifluralin inhibited root development of 25 day-old plants. The 4 kg/ha alachlor treatment reduced shoot weight of 25 day old plants significantly and suppressed mycorrhizal development of 25 to 60 day old plants. At currently used commercial rates neither alachlor, trifluralin, nor diazinon affected mycorrhizal development under the conditions of the experiment.

Acetanilides↗
PubMed1991

Initiation of acellular extrinsic fiber cementum on human teeth. A light- and electron-microscopic study.

The development of acellular extrinsic fiber cementum (AEFC) has never before been studied in human teeth. We have therefore examined the initiation of AEFC in the form of a collagenous fiber fringe and its attachment to the underlying dentinal matrix, in precisely selected, erupting human premolars with roots developed to 50%-60% of their final length. Freshly extracted teeth were prefixed in Karnovsky's fixative, decalcified in EDTA and subdivided into about 10 blocks each, cut from the mesial and distal root surfaces, vertical to and along the root axis. The blocks were postfixed in osmium tetroxide, embedded in Epon and cut for light- and electron-microscopic investigation. Starting at the advancing edge of the root, within a region extending about 1 mm coronal to this edge, fibroblast-like cells were seen closely covering the external root surface. Along the first 100 microns from the root edge, these cells extended cytoplasmic processes and contacted the dentinal collagen fibrils. Between these cells and the dentinal matrix, new collagen fibrils and very short collagen fibers gradually developed. Within the second 100 microns from the root edge, this resulted in the formation of a cell-fiber fringe network. Newly formed fibers of the fringe were directly attached to the non-mineralized matrix containing dentinal collagen fibrils and could be distinguished from the latter by differences in fibril orientation. During the process of dentin mineralization, the transitional zone between the fiber-fringe base and the dentinal matrix, i.e., the future dentino-cemental junction, also mineralized. It is suggested that this fiber fringe is the base of AEFC, which later increases in thickness by fiber extension and subsequent mineralization.

Bicuspid↗
PubMedDate not supplied

Multiple localized root agenesis.

The cause of this condition is undetermined. Cessation of root development is associated with a variety of systemic, congenital or genetic disorders. External trauma, such as radiation and electrical burns, can arrest development.

Adolescent↗
PubMed1991

[The tooth transplant in orthodontic treatment planning].

The analysis of all examined transplant cases combined treated with orthodontics shows a success rate of 76%. It must be underlined that the germ development at the time of the transplantation is of utmost importance. The best possible time proved to be at a root development of 2/3 to 3/4. Exact indication position, a careful atraumatic operation method and a short time of operation are also important factors of a successful transplantation. If all these preconditions are met, this method can be recommended.

Adolescent↗