Factors determining the outcome of scaling and root planing

Scaling and root planing are the predominant and recognized forms of periodontal therapy. They have been known for centuries, and have been investigated with increasing intensity since the turn of the century. Scaling and root planing aim at therapeutic changes of the "hard tissue lesion" at the root surface, in order to render it biologically acceptable to cells capable of attaching to it. Two major components of these root surface alterations are calculus and cementum alterations. Numerous studies have shown that scaling and root planing effectively removes subgingival deposits, and that this removal is seldom complete in deeper pockets. Even though beneficial clinical effects of scaling and root planing have been shown, it is unlikely that the full potential of healing is utilized today due to technical shortcomings. Several studies have shown that the design and dimensions of curets as used today are not optimal. These instruments are for many situations too big, subject to rapid dulling, and produce a smear layer. Chemical agents have been used to remove this layer with limited success. The therapist is a virtually unknown factor in the system of delivering scaling and root planing. A recent study showed that scaling and root planing forces used by different therapists on similar root surfaces varied by factors greater than 10. In addition, higher forces were shown to remove significantly more root substance. Apparently there is a large subjective component included in the delivery of scaling and root planing therapy. Even though scaling and root planing have been shown to be effective therapeutic procedures, many aspects require more research.     

Subclinical surface alterations of human pleura. A scanning electron microscopic study

Pleuritis or pleural effusion frequently develops in patients with pneumonia or heart failure. Most of these pleural changes regress without intrapleural intervention. The detailed mechanisms of the regression of the pleural changes in humans are not well documented. We studied the parietal pleura of nine patients with lung cancer and two patients with coronary artery disease by scanning electron microscopy (SEM). All patients had neither radiographic nor gross evidence of pleural disease but all had mixed surface alterations by SEM. Focal denudation of mesothelial cells was common. Deeper injuries exposed thick and thin interweaving collagen bundles. Patchy depositions of amorphous or crystallized fibrin covered normal and damaged pleural surfaces, frequently admixed with macrophages, red blood cells, and tissue debris. Reactive mesothelial cells appeared to proliferate over the fibrin. Our findings suggest that subclinical pleural alterations occur often in patients with pulmonary or cardiac diseases and that an intact pleural surface in those patients is restored mainly by the proliferation of reactive mesothelial cells.     

Luminal epithelium of Warthin's tumours: a scanning electron microscopic study

Three cases of papillary cystadenoma lymphomatosum were examined by light and scanning electron microscope to declare the morphology of the luminal epithelial surface. It was found that ciliated cells were present in one case. This finding explains the origin of ciliated cells as a development included in the neighbouring lymph node with a tendency of metaplastic change and exfoliation.     

A combined scanning and transmission electron microscopic study and electron probe microanalysis of human pineal acervuli

The frequency of postoperative infections in oncologic head and neck surgery can be reduced by the prophylactic use of antibiotics. In order to assess such preventive treatments as to their advantages and disadvantages, a controlled clinical trial was undertaken. The prophylactic use of antibiotics was used in 107 patients, operated for tumors of the upper airway-digestive tract. According to a previous randomisation, the patients received either carbenicillin either ticarcillin. The efficiency of carbenicillin and ticarcillin proved similar. The results obtained with these antibiotics turned out to be superior to those previously obtained with combined ampicillin and cloxacillin; the number of wound infections, primary and secondary, was lessened. The most frequent complications were thrombophlebitis at the site of intravenous perfusion of the antibiotics and hypokaliemia.     

A scanning electron microscopic study of the degenerative cartilage in patellar chondropathy

Patellar chondropathy as cartilage degeneration localized in patellar cartilage in young persons is characterized by cartilaginous changes, such as softening, swelling, and fissuring. With a view to structural characterization of early cartilaginous degeneration before erosion, the morphology of affected cartilage was studied under a scanning electron microscope. The surface network of cartilage constituting fibrils had an edematous change, presenting with fibrillation on the medial facet, whereas many fibrils of the central ridge had a collagen bundle, and fissuring of varying size was observed. It appeared that a mechanical force (shearing) acting on the site of the central ridge was associated with the formation of a collagen bundle and its destruction. On the lateral facet, fibrils were arranged perpendicular to the joint surface; the superficial layer of fibrils was worn by hyper-pressure acting on the lateral facet. On the fractured surface, the coarseness of collagen fibrils showed changes that varied with the site and stage of cartilage degeneration. Frequent changes were signs of fibril loosening (coarsening), such as reduction in fibril density (i.e., edematous change), collagen fibril aggregation, and fissuring, and longitudinal restructuring of fibrils. The patellar cartilage in the patients of this series showed a structure adapted to the mechanical force. The initial structural changes of cartilage consisted of collagen fibril aggregation and reduction in fibril density. These changes give rise to matrix rarefaction, which in turn causes cartilage degeneration to progress. These changes were concurrent in both the superficial and middle layers and were not localized as basal degeneration.     

A new cell type in the taste buds of anurans. A scanning and transmission electron microscopic study

A hitherto undescribed cell type within the fungiform papillae of the tongue of the toad, Bufo bufo (L.) and the taste-disks of the soft palate of Bombina variegata L. was identified by means of scanning and transmission electron microscopy. This cell type is characterized by an apical protrusion carrying numerous microvilli. Bundles of filaments are present in the cytoplasm of the protrusion. Vesicles with electron lucent content and microtubules are present thoughout the cytoplasm of the cell.     

A scanning and transmission electron microscopic study of experimental extrahepatic cholestasis in the rat

The rat liver after extrahepatic biliary obstruction was studied by SEM and TEM in correlation with basic histochemical techniques. Cholestasis was verified by serological methods. The biochemical data (increase in serum bilirubin values, a gradual lowering of the albumin fraction), in agreement with the ultrastructural results of a sparse RER, suggested a gradual decrease of the protein synthetic activity of the hepatocyte. SEM and TEM revealed numerous fat-storing cells, closely associated with patches of connective fibrils in the subendothelial spaces. Further ultrastructural observations demonstrated: a) a proliferation of the intrahepatic biliary tree (ductular proliferation, including newly formed ducts with sacculation and diverticuli); b) an increased number of canaliculo-ductular junctions and, c) an increase in the length of the bile canalicular network due to its tortuous course, pocketing and side branching. The occurrence of an intact cytoplasmic barrier separating the bile canalicular lumen from the Disse's space together with the results obtained by retrograde infusion of ferritin into the biliary tree suggested that the regurgitation pathway by ductular reabsorption and by transhepatocytic transport is the best documented and most acceptable, at least in the rat.     

A scanning and transmission electron microscopic study of fiber arrangement in the hepatic capsule

The arrangement of fibrous elements in the rat hepatic capsule was examined under a scanning electron microscope (SEM) after alkaline or acid maceration of the serous coat, in conjunction with examination of the thin sections using a transmission electron microscope (TEM). The elastic fibers appeared as thin threads in a densely meshed network, lying just beneath the serous coat. Their surface was granular with short rods in the materials fixed with paraformaldehyde. In contrast, the collagen fibers were observed as relatively thick threads, with fascicles of collagen fibrils that were uniform in size. These fascicles extended in various directions to form rough meshes that were traversed by small fascicles and anastomosed with each other. The fibrous branches of the elastic fibers extended on or into the underlying collagen fibers to be anchored, while the collagen fibers converged on many areas of the liver surface, and were transferred into the interlobular connective tissues. The findings of the present study thus suggest that the fiber arrangement plays an effective role in the mechanical protection of the fragile liver cells and delicate serous cells from pressure and friction damage by the neighboring abdominal organs and walls of the abdominal cavity due to the elastic mobility of the subserosal elastic network in addition to the possible slippery cushion of a serous layer on the serous cells.     

Vacuolated meningioma. A light and electron microscopic study

Two unusual cases of meningioma with extensive vacuolization have been studied by light and electron microscopy. There were two kinds of vacuoles in the tumor cells which had the characteristic ultrastructure of meningioma as well. The smaller intracytoplasmic vacuoles were lipid droplets, while the larger, more prominent vacuoles were found to be extracellular spaces probably containing plasmatic fluid. The tumor cells were very much stellate with extremely thin and long cytoplasmic processes having desmosome junctions and forming cavernous intercellular spaces, some of which contained collagen fibers and fibrils. Although the xanthomatous change has been well known, the latter features provide a resonable interpretation for the histology of the present tumors and fat-negative vacuoles in the ordinary meningiomas. The picture may be recapitulation of the subarachnoid structure. Furthermore, recognition of this type of meningioma is practically important especially in frozen section diagnosis not to misinterpret the tumor as liposarcoma, chordoma or metastatic adenocarcinoma.     

The effects of kinetic variables on the structure of copper deposits cemented on pure aluminum discs: A scanning electron microscopic study

The structural characteristics of copper deposits resulting from copper cementation on pure aluminum are presented. The effect of chloride ion concentration, rotational speed of the aluminum disc, hydrogen ion concentration, copper ion concentration, and temperature on the nature and morphology of the deposits was investigated. Different copper deposit structures, viz. bulbous, massive crystalline, thick dendrites with leaf-like secondary arms, and dendrites of different degrees of fineness and texture were observed in the present study utilizing the scanning electron microscope. Deposit morphology was greatly modified for variations of chloride ion up to 25 mg l^?1 and for increases in temperature up to 40° C. The maximum rate of copper cementation on pure aluminum was usually associated with a fine, dendritic structure.     

Microvascular system of the rat incisor enamel organ. A scanning electron microscopic study of vascular corrosion casts

The rat incisor is a commonly used model in studies of tooth eruption, amelogenesis and effects of mechanical loading on the dental and periodontal tissues. The purpose of this study was to assess the three-dimensional architecture of the microvascular bed of the rat incisor enamel organ, to describe the direction of blood flow, and to provide a histometric assessment of the vascular categories that can be statistically analyzed. Vascular corrosion casts were prepared and examined by scanning electron microscopy. The microvasculature of the labial periodontal space was arranged in three distinct layers. The inner layer in direct relation to the enamel organ consisted of a capillary network which was drained by short venules at the cemento-enamel junction. The intermediate layer consisted of arterioles oriented parallel to the long axis of the incisor mainly mid-labially, branching off smaller arterioles to the capillary network. The outer layer was formed by flattened sinusoid vessels of larger caliber. Blood supply was from the anterior superior alveolar artery branches through the arterioles into the capillary network. Drainage was postero-laterally along the cemento-enamel junction via short venules which emptied into the sinusoid vessels, finally to flow through Volkmann's canals into the alveolar bone via small venules. The findings demonstrate that the microvasculature of the rat incisor enamel organ has an exceptionally high level of physiologically-adapted structural organization.     

Meningioma and intracranial hemangiopericytoma. A comparative electron microscopic study

Electron microscopic study of 2 intracranial hemangiopericytomas and 7 meningiomas revealed fundamental morphologic differences between the 2 neoplasms. The most significant finding in hemangiopericytoma was the presence of ultrastructure features suggesting leiomyoblastic differentiation. These included characteristic fusiform intracytoplasmic and submembranous dense bodies, abundant cytoplasmic filaments, elongated cells with blunt-ended nuclei and juxtanuclear polarization of organelles. This observation is considered highly significant as an indicator of the pericytic nature of this tumor. In addition, hemangiopericytoma cells sometimes were arranged in spirals around pools of basement membrane-like material, perhaps a manifestation of the biologic capability of the cells to synthetize such material. Meningioma cells displayed as their main feature an ability to produce surface membrane specializations including interdigitations, desmosomes, zonulae adhaerentes and gap functions. Sometimes the last 3 elements were linearly juxtaposed forming junctional complexes similar to those seen in certain epithelia. It is suggested that the characteristic whorls of meningioma are the result of cell interconnections arising from the specialized junctional attachments. Thus the distinctive morphology of the 2 neoplasms appears to derive from basic biologic properties of their elements.     

Fluoride toxicity: a biochemical and scanning electron microscopic study of enamel surface of rabbit teeth

The present study has been carried out to investigate the effect of fluoride toxicity on the morphology as well as inorganic chemical constituents of rabbit teeth. Rabbits were administered sodium fluoride at a dose of 10 mg NaF/kg body weight every 24 h for 18 and 23 months. The incisor and molar teeth (whole tooth) were investigated for fluoride, calcium and phosphorus content in 18- and 23-month treated animals. The enamel surfaces of incisor teeth of 23-month treated animals were examined under scanning electron microscope. A significant increase in fluoride levels and significant decrease in calcium content was found following fluoride administration for 18 and 23 months as compared to control. Ca/P ratio was significantly increased only in 23-month treated animals. The scanning electron micrographs revealed hypoplastic, rough, uneven, pitted and cracked enamel surfaces covered with granular deposits as a result of excessive intake of fluoride. It can be concluded that long term fluoride administration leads to severe structural alterations on the enamel surface, possibly through defective mineralization.     

Bacterial penetration through Resolut resorbable membrane in vitro. An histological and scanning electron microscopic study

PURPOSE: To define early anatomic changes in the aorta in an in vitro hydrostatic model of acute aortic dissection. MATERIALS AND METHODS: Aortic dissections were created in explanted aortas. A small portion of the dissection flap was resected to allow free communication between the true and false lumina. The aortas were suspended in a saline bath and distended by means of a saline fluid column. By using intravascular ultrasonography, the arc lengths of the outer walls of the true and false lumina and of the dissection flap were measured at increasing hydrostatic pressures and at increasing fractions of dissected wall circumference. RESULTS: The dissected aorta immediately became ectatic. At a given fraction of wall circumference involved in dissection, total aortic cross-sectional area increased with increased hydrostatic pressure. At a given hydrostatic pressure, this area increased with increased fraction of wall circumference dissected. Most of the increase was due to dilatation of the false lumen. There were minimal changes in true-lumen size. Dissection flap length, after initial contraction at the time of dissection, changed minimally with increasing pressure. CONCLUSION: Anatomic changes in the dissected aorta depend on hydrostatic pressure and on the percentage of aortic wall involved in the dissection.     

Comparative surface studies of ototoxic effects of various aminoglycoside antibiotics on the organ of Corti in the guinea pig. A scanning electron microscopic study

It was the purpose of this study to establish criteria for use in comparing the toxic effects of aminoglycosid antibiotics on the organ of Corti by means of scanning electron microscopy. Amikacin, Tobramycin and Gentamicin were administered twice a day subcutaneously for 10 days to healthy guinea pigs. One group of animals was sacrificed 1 day after completion of the treatment; the other group was allowed to survive 22 days. Depending upon the dosage of the administered drug, Amikacin (150 mg per kg body weight daily, corresponding to 10 times an average recommended human dose) caused pronounced outer hair cell damage even 1 day after the treatment was stopped. At this time Gentamicin and Tobramycin (150 mg per kg body weight daily, corresponding to 50 times an average human dose) showed less damage. After 22 days' survival, late toxic effects were found mainly in Gentamicin- and Tobramycin-treated animals. After 3 weeks, nearly total outer hair cell loss was found in the basal coil, while the 2nd and 3rd coils were often less severely damaged. At this time Amikacin-treated animals showed severe damage in all coils. 300 mg per kg body weight Amikacin (i.e. 20 times the average human dose) showed about the same toxic effect on sensory cells of the guinea pig as did 150 mg Gentamicin or Tobramycin per kg body weight. We are conscious of the fact that there are problems in correlating the weight of a drug and its probable toxic effect. In comparative animal experiments we consider it useful to standardize the time of exposure, the amount of drug administered (e.g. related to the human dose) and the survival time.     

Cell membrane maturation of Friend erythroleukemic cells and tocopherol-dependent erythropoietin effect: a scanning electron microscopic study

Typical morphological features of surface structural alterations during Friend cells differentiation are described. Scanning electron microscopy (SEM) revealed that DMSO induction switched on cell alteration of the proerythroblast-like cells, possessing microvilli projections on cell membrane with some ruffles, to an advanced stage with a blebby surface. This was followed by the formation of a pear-like polarized cell separated into two zones by a narrow cytoplasmic bridge at the equatorial plane. The polarized cells showed a smooth surface and tended to disconnect into two unequal cells. The villous leukemic erythroblast has negatively charged sialic acid residues on the glycocalyx, available for latex hydrazide probe binding, while the blebby and polarized cells lack it. Tocopherol added to culture medium of DMSO-induced erythroleukemic cells prevented the formation of blebs and the polarization phenomena, without affecting hemoglobin synthesis. The tocopherol-treated cells contain available negative charges for latex hydrazide binding similar to uninduced Friend cells. Erythropoietin potentiated a repolarization ability and morphological alteration capacity to the tocopherol-treated cells and this was accompanied by a loss of glycocalyx-negative charges. At these growth conditions erythyropoietin induced a dose-dependent proliferation effect.     

A scanning and transmission electron microscopic study on rat bone marrow sinuses and transmural migration of blood cells

Bone marrow sinuses of young rats were examined under the scanning (SEM) and transmission electron microscopes (TEM). Marrow sinus wall was composed of three layers: an inner or luminal endothelium, an outer or adventitial cell layer, and a basal lamina in between. The luminal surface of the endothelial cells was quite smooth and showed some fenestrations, which could be divided into two types according to their size. One was represented by larger fenestrations (1-3 mum in diameter) which were presumed to be formed transiently at the site of blood cell migration, while the other by small pores (0.1 mum) grouped into a cribriform area. The adventitial cells showed a discontinuous layer in the TEM. Under the SEM, the discontinuity corresponded to the spaces formed between the cytoplasmic attenuations of the cells. Blood cell migration from the extravascular hemopoietic tissue into the sinus lumen was numerously observed. The migration occurred not through an intercellular gap, but through the larger intracellular fenestration of the endothelial lining mentioned above. A number of megakaryocytes were identified by their bulky cytoplasm in the parenchyme. Figures suggesting the sequence of platelet liberation from this cell could be demonstrated. First, the megakaryocyte extended its peripheral cytoplasmic processes into the sinus through endothelial fenestrations. The processes, being conspicuously extended, became periodically constricted. Finally, platelets were believed to be produced by separation at the constricted portions and liberated to circulation. The occurrence of a few endothelial fenestrations apparently unassociated with blood cell migration may possibly be ascribed to detachment of a blood cells due to vascular perfusion. The functional significance of the adventitial cell was discussed in association with blood cell migration.     

Clinical response of localized recurrent periodontitis treated with scaling, root planing, and tetracycline fiber

The purpose of this study was to compare the clinical efficacy of scaling and root planing alone versus tetracycline fiber therapy used adjunctively with scaling and root planing in the treatment of nonresponsive active periodontitis in patients under supportive periodontal therapy. Thirty patients who were receiving supportive treatment and had at least two nonadjacent periodontitis sites with a probing depth of between 4 and 8 mm and bleeding on probing, or had aspartate aminotransferase (AST) levels above 800 microIU in the gingival crevicular fluid in separate quadrants participated in this study. For each patient, the test sites were treated with scaling and root planing plus tetracycline fibers while the control site was treated with scaling and root planing only. Probing depths, clinical attachment levels, gingival recession, AST levels, and bleeding on probing were recorded and subgingival plaque samples were collected at baseline and 1, 3, and 6 months following treatment. At 3 months after treatment, there was a reduction of bleeding on probing and probing depth, and a gain of clinical attachment in both test and control sites. The mean reduction in probing depth of the test sites was 1.38 mm and the attachment gain was 0.8 mm after 6 months. The clinical response obtained at 3 months following therapy was maintained throughout the 6-month follow-up period. However, there were no statistically significant differences between sites treated with scaling and root planing alone and those treated with combined tetracycline therapy. Most of the reductions of probing depths in the fiber group were attributed to gingival recession. The present study did not confirm the efficacy of adjunctive tetracycline fibers in treating nonresponsive sites in maintenance subjects with regard to probing depth reduction or clinical attachment gain. Reinfection of the pockets from untreated sites and extra-crevicular regions may explain the insignificant response to local tetracycline therapy.     

Morphological variations of the human gastric mucosa after omeprazole treatment: a scanning electron microscopic study

The effects of antiepileptic drugs on cognitive function in 48 healthy volunteers were assessed using event-related potentials (ERP) and the Attention Index included in the Wechsler Memory Scale, revised edition (WMS-R). The study was conducted over 1 week, using a double-blind design. Four drugs, carbamazepine (CBZ), phenytoin (PHT), valproate (VPA) and zonisamide (ZNS) were tested. Using an auditory oddball task, ERP measurements were made under two conditions with different tone intensities: Condition 1 used 70 db SPL; and Condition 2 used 30 db SPL. Results showed that CBZ prolonged target N1 and P3 latencies in Condition 1, and reduced frequent N1 amplitude in Condition 2, which suggests that CBZ may cause a change in sensory memory and prolong stimulus evaluation time. It is suggested that under a low stimulus intensity level, the sensory function itself was affected. Phenytoin was found to prolong target N1 latency in Condition 2, which also indicates a change in the sensory memory function. However, VPA did not significantly affect ERP components, except for the shortened frequent N1 latency, which could not be explained due to the limited information. It was found that ZNS augmented P3 amplitude in Condition 2, and reduced scores on the Attention Index. It is suggested that the augmentation of P3 amplitude was caused by the reduction of processing negativity as a result of the detrimental effect of ZNS on subjects' attention. However, the apparent difference between the ERP and behavioral indices suggests that caution should be exercised in assessing the results obtained only from ERP measurements.