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Primary tooth ankylosis: report of case with histological analysis.

Two primary molars in infraclusion showing clinical and radiographic signs of ankylosis, were subject to histological examination by bright field and polarization microscopy. The roots revealed signs of ongoing resorptive and reparative processes and in some areas dentin with signs of resorption-or repair cementum-were fused with simple lamellar or osteonic bone. These results suggest that ankylosis of primary molars can result from a disturbance of root resorption, with repair processes prevailing over resorptive ones and leading to excessive deposition of bone besides cementum-as a consequence of bone-inductive properties of dentin.

Alveolar Process↗

Combined microautoradiographic and histopathologic analysis of the fate of challenge Schistosoma mansoni schistosomula in mice immunized with irradiated cercariae.

Combined microautoradiographic and histopathologic methods were used to locate and examine schistosomula of Schistosoma mansoni in the lungs of irradiated cercaria-immunized mice 21 days after percutaneous challenge infection with 75Se-labeled cercariae. Of 75 schistosomula examined in serial sections, 53% were located in the pulmonary microvasculature, 23% in alveolar spaces, 3% with one end in a vessel and the other in an alveolar space, and the locations of 21% were not identified. Inflammatory reactions of variable intensity were observed around schistosomula in both vascular and alveolar sites, although the most intense category of reactions was associated almost entirely with alveolar larvae. All autoradiographic foci contained recognizable schistosomula. Although the concentration of reduced silver grains precluded cyto-structural analysis, observations on schistosomular contour and shape provided no evidence of larval damage. Our findings suggest that immune elimination of schistosomula in mice immunized with irradiated cercariae is partly or largely effected by a process of alveolar extrusion of viable parasites during their lung migration.

Animals↗

Two-stage impression technique for overdentures.

Overdentures are supported by hard tissue and resilient tissue. Optimum distribution of functional load between these different tissue types is a challenge. A two-stage impression technique is proposed to eliminate much of the need for finished denture base modification. A first stage impression is made of the resting form of the soft tissue and is used to make a mucostatic metal base. A second impression is developed under occlusal pressure with modeling compound applied to the border and the surfaces of the metal base overlying the abutments. This procedure establishes border seal and relates ridge tissue displacement to the abutments. A final cast is made by using the metal base and modeling compound. Heat-cured acrylic resin is processed to the metal base on this cast. Adjustment of the tissue surface of the base is limited to surfaces overlying free marginal gingivae and axial surfaces of the abutments.

Alveolar Process↗

Assessing dental practice quality by evaluating radiology items.

The DEMCAD dental office assessment instrument was developed to evaluate practice quality using Donebedian's quality assessment model of structure, process, and outcome. This previously validated instrument takes about six hours to complete. Subsequent analysis was undertaken to determine whether an abbreviated office assessment based on the evaluation of radiology items was sufficiently sensitive, specific, and practical to be used as a screening instrument for identifying dental offices with very low evaluation scores. Data for this analysis were obtained from 300 volunteer general dental practices evaluated in the field testing of the DEMCAD instrument. The nine radiology structure items predicted very poorly the overall structure scores. However, 13 radiology process items predicted overall process scores quite accurately. Four of the 13 radiology process items (periodontal diagnoses recorded, interdental bone shown on x-rays, caries diagnoses recorded, and current x-rays mounted) produced a combined R2 of .58. These four radiology variables predicted the 10 percent of the dental practices with the lowest overall process score with 87 percent sensitivity and 93 percent specificity. This analysis showed that an abbreviated dental practice process quality assessment using oral radiology items in an audit of patients' records may be feasible as a screening test for dental office assessment.

Alveolar Process↗

[A clinical and experimental validation of the use of Stimuloss in patients with chronic generalized periodontitis].

The pharmacological effect of hydroxyapatite and a composition based on it in the form of Stimulos sponge has been studied in human osteogenic tissue culture. Hydroxyapatite stimulated the biosynthetic processes in the cells. Addition of chlorohexidine and thymogen to the composition in order to increase its antibacterial activity did not decrease the osteoinductive properties of the drug. Trials of Stimulos in 66 patients with chronic generalized periodontitis demonstrated its high efficacy, particularly of the compositions containing immunostimulants: inflammation disappeared and the height of alveolar osseous tissue increased, as did bone compactness.

Adjuvants, Immunologic↗

The role of CC chemokine receptor 2 in alveolar monocyte and neutrophil immigration in intact mice.

The CC chemokine ligand 2 (CCL2) (JE, monocyte chemotactic protein-1 [MCP-1]) and its CC chemokine receptor 2 (CCR2) are critical regulators of monocyte/macrophage trafficking. Recently, we demonstrated that application of exogenous CCL2 in the lungs of mice induced monocyte accumulation in the airspace, whereas combined bronchoalveolar instillation of CCL2 and Escherichia coli endotoxin provoked both enhanced monocyte accumulation and extensive neutrophil influx associated with loss of pulmonary endothelial/epithelial barrier function. In this study, we investigated the role of the CCL2 receptor CCR2 in alveolar leukocyte traffic. In CCR2 knockout mice or wild-type mice treated with the anti-CCR2-blocking monoclonal antibody MC21, monocyte accumulation in response to alveolar CCL2 or CCL2 plus endotoxin was inhibited by more than 90%. Unexpectedly, alveolar neutrophil accumulation in the CCL2/lipopolysaccharide (LPS) model was also drastically reduced by both approaches of CCR2 function interference. When wild-type mice treated with anti-Gr-1 monoclonal antibody to deplete neutrophils selectively or treated with antileukinate, a CXC receptor inhibitor, were challenged with alveolar CCL2 plus LPS, alveolar monocyte accumulation was markedly decreased. Wild-type mice treated with MC21 to block CCR2 function or with anti-Gr-1 to deplete neutrophils did not exhibit the vascular leakage that typically accompanies inflammation triggered by CCL2 and LPS in wild-type mice. These findings confirm a central role for CCR2 in the process of alveolar monocyte recruitment in response to CCL2 alone and combined CCL2 plus LPS and reveal a previously unobserved interdependence between monocyte and neutrophil trafficking that has important implications for the concomitant increase in vascular permeability.

Acute Disease↗

[An experimental study on healing process of replanted mature permanent teeth. Changes of periodontal vascular network].

This study was conducted to clarify both changes of periodontal vascular architecture and concomitant remodelling phenomena associated with hard tissues in the healing process of replanted teeth of first premolar. Utilizing both vascular corrosive resin casts method, scanning electron microscopy, and histological examinations, 45 matured mongrel dogs were used for this study. The results were as follows: 1. 4 days after operation: Newly formed vascular networks with a exceedingly irregular course were observed on lower two thirds of the alveolar wall. They derived from comparatively less damaged periodontal vascular components. No vascular networks were observed surrounding in the crevicular area of the replanted tooth where the periodontal membrane tissue was thoroughly damaged when tooth was extracted. 2. 1 week after operation: Newly formed periodontal vascular networks with a slightly irregular course were observed over the entire alveolar bone surface. 3. 2 weeks after operation: Formation of Sharpey's fibers occurred. The surrounding alveolar bone was remodelled and rearrangement of periodontal vascular architecture was observed. Also, several Howship's lacunae were observed on the root surface where characteristic capillary loops with glomerular-like appearance penetrated into these lacunae. 4. 3 weeks after operation: Root resorption was advanced and capillary loops with glomerular-like appearance were extensively distributed in association with each lacunae. On the other hand, the less space where periodontal membrane vasculature occupied, the more space was occupied by osteoid tissue. 5. 4 weeks after operation: Blood vessels within the periodontal space were reduced in number and the osteoid tissue showed bony fusion adjacent to the extensively resorbing surface of dentin. 6. 12 weeks after operation: Functional arrangement of Sharpey's fibers was completed. Restoration of Howship's lacunae on the root surface and two layered arrangements of vascular network within the periodontal space were observed. Newly formed periodontal vascular architecture showed a fine meshwork pattern, which was somewhat different from that of the control (noreplantation) group. 7. 20 weeks after operation: Increased number of capillary loops was observed with leakage of methacrylate resin through the weakened endothelial linings of capillaries in one case. It is supposed that this leakage through capillaries is correlated with the inflammatory root resorption that occurs clinically in marginal periodontitis. Also in some cases, periodontal capillary network showed secondary occlusal traumatic changes. Above results indicated that periodontal vascular architecture varied depending upon the reactions of periodontium following tooth replantation and the prognosis of replanted tooth was deeply associated with repair of periodontal vascular network.

Alveolar Process↗

On the dynamics of periodontal tissue formation in degree III furcation defects. An experimental study in dogs.

The aim of the experiment was to describe the formation of periodontal tissues in degree III furcation defects following GTR therapy. The study was performed in 8 foxhound dogs. The 2nd and 4th premolars in both sides of the mandible were extracted. Furcation defects were produced in the 3rd mandibular premolars. 3 weeks later, reconstructive surgery was performed. The dogs were scheduled for sacrifice 2, 4, 8, and 20 weeks after GTR therapy. Tissue blocks containing the experimental teeth were excised, demineralized in EDTA and embedded in paraffin. Serial sections were cut in the mesio-distal plane and parallel with the long axis of the roots. The microtome was set at 7 microns. The sections were stained in hematoxyline and eosin. From each biopsy, 3 sections representing the central part of the furcation, were selected for light microscopic examination. In the healed furcation sites, descriptive histological analysis of the newly-formed tissues was performed and the relative proportions of the hard and soft tissues were determined. It was demonstrated that at 2 weeks, the furcation defect contained granulation tissue and cell-rich connective tissue, while at 4 weeks the furcation was mainly occupied by connective tissue. At 8 weeks, woven bone occupied the central portion of the furcation, whereas connective tissue and cementum were observed in the lateral portions. The furcation area at 20 weeks was comprised of newly-formed cementum, periodontal ligament and bone. The onset of cementum formation had started as early as 2 weeks after GTR therapy. The cementum formation apparently occurred in 3 phases: organisation of collagen fibers adjacent and perpendicular to the root surface (phase 1), assembly of the collagen fibers and deposition of matrix (phase 2), and addition of cells and collagen fibers organised parallel to the root surface (phase 3). Bone formation took place through a process that included (1) organisation of a fibrous connective tissue, (2) differentiation of this tissue into woven bone and, (3) maturation of the woven bone into lamellar bone and bone marrow.

Alveolar Process↗

Dimensional changes and pressure of dental stones set in silicone rubber impressions.

OBJECTIVES: A high expansion stone has been used for improving the adaptation of dentures. Although the method is based on the idea to compensate for the processing shrinkage of the denture base resin with the high expansion stone, there are few studies on the expansion behavior of stones in an impression. The purpose of this study is to clarify the dimensional changes of stones set in silicone rubber impressions using two types of impression tray. METHODS: Impressions of a master model that represents the alveolar ridge were taken using a silicone impression material and the dimensional changes in the stone casts were measured in different directions (x, y and z-axes). Two types of impression tray were used, one with an open surface and the other with a closed surface. In order to evaluate the setting expansion of the stones and the pressure against the impression, stones were poured in other impressions that were taken from a cubic master model. The thickness of the impression was set at 2 mm. RESULTS: A statistical analysis showed that there were significant differences in the dimensional change in the vertical direction (z-axis) and horizontal directions (x- and y-axes) of any stone casts set in the open tray. However, there were no significant differences in the dimensional changes in any direction of each stone cast set in the closed tray. SIGNIFICANCE: The impression tray influences the setting expansion of stones. Stones do not uniformly expand in the open tray and the dimensional changes in the stone casts in the three-dimensions increases, when used with a high expansion stone.

Alveolar Process↗

The pattern and control of eruptive tooth movements.

Assumptions about eruptive tooth movements based on experience with adolescents may not be applicable to all ages. The eruptive process can be subdivided into six phases--three profunctional stages of individual tooth eruption (follicular growth, pre-emergent eruptive spurt, and postemergent eruptive spurt) and three postfunctional stages of the eruption of the entire dentition (juvenile occlusal equilibrium, circumpubertal occlusal eruptive spurt, and adult occlusal equilibrium). Differences in tooth-eruption rates in each of these phases result from variations in systemic and local factors. A series of working hypotheses which incorporate recent research into a theoretical explanation of the control of eruption during each stage is presented. Prior to emergence, the force of eruption may influence the rate of bone resorption and later of gingival remodeling, but the resorptive processes occur independently and are the rate-limiting factors in pre-emergent eruption. After emergence, intermittent occlusal loading disrupts the generative or adaptive mechanisms of the periodontal ligament so that eruption slows. The light continuous forces from resting tongue pressure also are significant influences on tooth eruption during periods of rapid facial growth. Cellular adaptation of the alveolar bone and gingiva plays an important role in the control of tooth eruption in the adult.

Adolescent↗

Denture stomatitis. A clinical, electron-microscopic, microradiographic and light-microscopic study.

The present study includes a reexamination of 10 patients who, two years ago received complete upper and lower denture treatment to eliminate an existing denture stomatitis. Clinical healing of the denture stomatitis was obtained only in one patient, whereas the remaining nine patients wtill displayed an obvious denture stomatitis. Biopsies were taken from the palatal mucosa and examined histologically, microradiographically, and by electron microscopy. The results of these examination indicated that, in denture stomatitis there is a reduced thickness of the epithelium, an absence of a stratum corneum, a markedly widened intercellular space, especially in the stratum basale, and an intense infiltration of inflammatory cells, plasma cells and lymphocytes in the connective tissue, as well as in the epithelium. These changes are characteristic features of an inflammatory process, and similar to the changes which occur, for example, in chronic, marginal gingivitis. The composition of the inflammatory infiltrate suggested that, in denture stomatitis, immunological phenomena influence the pattern of the tissue reaction.

Alveolar Process↗

[Keratinocyte growth factor and Hepatocyte growth factor: their roles in alveolar epithelial repair].

INTRODUCTION: The alveolar epithelium is the principal target in the course of acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS) and to a lesser extent in chronic reactions like pulmonary fibrosis. STATE OF ART: Keratinocyte growth factor (KGF) and Hepatocyte growth factor (HGF) are potent growth factors for type II pneumocytes and seem to play a specific role in the process of alveolar repair. PERSPECTIVES: The studies conducted by our group have demonstrated 1) that KGF and HGF are present in biologically active concentrations in human pulmonary alveoli in ALI and ARDS, 2) that in these patients as well as those with pulmonary fibrosis circulating neutrophils are an important source of HGF. HGF and KGF act within a system involving other factors such as parathyroid hormone related protein (PTHrP). PTHrP acts in an autocrine and paracrine manner to regulate the balance between proliferation and apoptosis of alveolar epithelial cells. CONCLUSIONS: Our results obtained in humans suggest a beneficial role for neutrophils in the alveolar repair after acute or chronic lung injury. The experimental data suggest that use of KGF and HGF might be considered in the future in the treatment of human acute or chronic lung injury.

Acute Disease↗

Deposition and clearance of inhaled particles.

Theoretical models of respiratory tract deposition of inhaled particles are compared to experimental studies of deposition patterns in humans and animals, as determined principally by particle size, density, respiratory rate and flow parameters. Various models of inhaled particle deposition make use of convenient approximations of the respiratory tract to predict tractional deposition according to fundamental physical processes of impaction, sedimentation, and diffusion. These theoretical models for both total deposition and regional (nasopharyngeal, tracheobronchial, and pulmonary) deposition are compared with experimental studies of inhaled dusts in humans or experimental animals that have been performed in many laboratories over several decades. Reasonable correlation has been obtained between theoretical and experimental studies, but the behavior of very fine (less than 0.01 mum) particles requires further refinement. Properties of particle shape, charge, and hygroscopicity as well as the degree of respiratory tract pathology also influence deposition patterns and further experimental work is urgently needed in these areas. The influence upon deposition patterns of dynamic alterations in inspiratory flow profiles caused by a variety of breathing patterns also requires further study, and the use of such techniques with selected inhaled particle size holds promise in possible diagnostic aid in diagnosis of normal versus disease conditions. Mechanisms of conducting airway and alveolar clearance processes involving mucociliary clearance, dissolution, transport to systemic circulation, and translocation via regional lymphatic clearance are discussed. The roles of the pulmonary macrophage in airway and alveolar clearance are described, and the applicability of recent solubility models for translocation or deposited materials to liver, skeleton, or other systemic organs is discussed.

Aerosols↗

Vascular response of the periodontal membrane after replantation of teeth.

Thirteen replanted maxillary central incisors were studied by means of histologic and cleared sections to evaluate the pattern of revascularization of the periodontal membrane and the modification of its vasculature due to root resorption, dentoalveolar ankylosis, and periapical processes. Early reparative activity was noted in the apical and cervical parts of the replanted membrane where proliferating vessels were intermingling with reparative cells and interrupted collagenous fibers. These areas of the membrane corresponded with those receiving a better vascular supply after replantation. The middle third of the membrane, however, showed a scarcity or absence of reparative cells as a result of delayed revascularization. Root resorption, dentoalveolar ankylosis, or periapical processes changed both the tissue specificity of the replanted membrane and its pattern of vascular supply. Revascularization of the pulps showed vacuolar degeneration due to lack of nutrition.

Alveolar Process↗

[Role of salivary kallikrein in the pathogenesis of periodontosis].

In patients with parodontosis the distinct increase in salivary kallikrein secretion was found. In Wistar rats the intensity of age atrophy of alveoli dentalis correlated with BAEE-esterase activity of mixed saliva. Desalivation considerably decreased the rate of age atrophy of parodontosis in rats. Salivary kallikrein, penetrating in active form into parodontal tissues, caused the pronounced vasodilation in dogs and golden hamsters. By means of kallikrein preparations an intensive inflammatory-dystrophical process was reproduced in parodontal tissues of Wistar rats. The local treatment of patients with parodontosis by kallikrein inhibitors was found to be especially effective.

Acetone↗

Using recombinant platelet-derived growth factor to facilitate wound healing.

Recombinant human platelet-derived growth factor (rhPDGF-BB) is a bioactive protein that has been combined with bone graft materials in an effort to regenerate the periodontium to its prediseased state more predictably. The combination of a biocompatible scaffold with this highly purified, recombinant human growth factor capitalizes on PDGF's stimulatory effects on cellular migration and proliferation, with subsequent matrix formation, to drive the healing process toward regeneration. When using a growth factor such as rhPDGF-BB with broad wound healing activity, an added clinical benefit is the more rapid soft tissue wound healing pattern observed at the surgical site. This also may be seen as a patient-centered benefit because it allows dentists to provide for a patient's prosthetic care on a timely basis, leading to a faster return to normal function. Also, the patient may resume plaque control efforts earlier, which further facilitates the wound-healing process. The purpose of these 2 case reports is to document the use of rhPDGF-BB as a wound-healing agent in 2 clinical situations and to provide a rationale for its use in this capacity.

Aged↗