bluuebunny/crossref_metadata_2025 huggingface dataset:
Centrioles and cilia in palatal squamous epithelium in guinea pigs
Authors: FEJERSKOV O.
Published: October 2007

abstract – Centrioles are found in the juxtanuclear cytoplasm of palatal epithelial cells in guinea pigs in all cell layers except the stratum corneum. In the basal and the lower half of the spinous cell layers they are found in the Golgi area. Their fine structure corresponds to that seen in other cell types. Ciliogenesis and single cilia have been observed in basal cells and in cells from the lower half of the spinous cell layer. During ciliogenesis, when centrioles become basal bodies, one end is enveloped by a large vesicle and pericentriolar satellites are present near this end. Besides free cytoplasmic microtubules, pericentriolar microtubules occur emanating from the satellites. Adjacent to basal bodies, cross‐striated structures are often found. The microtubules of a cilium are a direct continuation of microtubules A and B of the basal body. Two central microtubules have not been observed in cilia of squamous epithelial cells. All cilia examined have been located intracellularly. It seems that cells with centrioles have the potentiality to form single cilia even though a special function may not be attributed to them.
Serologic properties of lipopolysaccharide endotoxins from oral fusobacteria
Authors: KRISTOFFERSEN T. , MAELAND J. A. , HOFSTAD T.
Published: October 2007

abstract–Phenol‐water extracted lipopolysaccharides (LPS) from four strains of fusobacteria were studied by hemagglutination and precipitation techniques. The results indicate that LPS from fusobacteria are serologically type specific. LPS from any one bacterial strain may contain more than one determinant group, carried by the same molecular complex. The determinant groups are of carbohydrate nature. Hemagglutination inhibition studies with mono‐ and disaccharides supported this concept and gave information on the chemical composition of one of four determinant groups detected in the four strains examined. Serologic activity of the protein component of LPS preparations could not be demonstrated.
Electron microscopy of human dentin exposed by attrition
Authors: TRONSTAD LEIF , LANGELAND KAARE
Published: October 2007

abstract – Undecalcified sections of human dentin exposed by attrition were studied by electron microscopy. Many tubules contained calcified deposits or inclusions with a high degree of variability in structure and density. The presence of big crystals, some needle‐like, others angulated and often rhombohedral, was conspicuous. The deposits seemed to be formed by a precipitation of minerals in the lumen, or by a repetitive deposition on the walls of the tubules. In the region of the last formed primary dentin, tubules without peritubular dentin occurred. Most of the tubules of the irritation dentin were surrounded by peritubular dentin of varying width and density. Groups of tubules contained a great amount of mineralized collagenous fibers, oriented parallel to the long axis of the tubule. The large angulated crystals were also present in tubules of the irritation dentin. Electron diffraction patterns indicated that the big needle‐like crystals were apatite in nature whereas the inclusions seemed to contain whitlockite when the angulated, rhombohedral crystals were present.
The three‐dimensional morphology of the epithelium‐connective tissue interface of the gingiva as related to age and sex
Authors: LÖE HARALD , KARRING T.
Published: October 2007

abstract – The morphology of the epithelium‐connective tissue interface was studied in gingival biopsy specimens of 29 male and 16 female Caucasians. Ten were 7–13 years of age, twenty 20–25, and fifteen 65–77 years of age. Separate three‐dimensional wax models (200 ×) were produced of the epithelium and connective tissue of the oral aspect of the free and attached gingiva. The average height, width, and number of connective tissue papillae or ridges and the average width of epithelial ridges were assessed for each specimen. In ten specimens of each age group measurements were made of the contact area between the epithelium and connective tissue. The length of the basement membrane and the volume of the epithelium was assessed within the same area. The essential age change of the epithelium‐connective tissue interface is the conversion of the connective tissue ridges to papillae. The contact area between the epithelium and connective tissue increases from the prepuberty to 20–25 years of age. The volume of the epithelium does not change with age. Sex‐related variations could not be observed.
A modified Millipore® technique for the study of oral leukocytes
Authors: RAESTE ANNA‐MAIJA , CALONIUS P. E. B.
Published: October 2007

abstract – A modified Millipore® technique for the study of oral leukocytes is presented. This technique permits rapid fixation with a minimum of injury to the cells. The clinical usefulness of the method was tested in a study of leukocytes in stimulated and whole salivas. The degenerative stages of PMN (polymorphonuclear) leukocytes were classified and estimated in a small group of healthy students. The results indicated that the method is suitable for this kind of study. In the Millipore preparations different leukocytes could be distinguished. The method is very simple and the samples can be handled routinely in cytologic laboratories.
Follow‐up study of periradicular bone condensation
Authors: HEDIN MANS , POLHAGEN LARS
Published: October 2007

abstract – The aim of the present study was to ascertain the fate of a radiographically diagnosed periradicular bone condensation. Clinical and radiographic examinations of 38 teeth were performed at the beginning and end of a follow‐up period of about 4 years. Radiopacity associated with a tooth whose pulp was found to be necrotic or gangrenous in most cases normalized after conservative root therapy. In other conditions of the pulp the radiopacity could persist for a long time in spite of appropriate root canal therapy.
Mast cells in inflamed human dental pulp
Authors: ZACHRISSON BJÖRN U. , SKOGEDAL OLE
Published: October 2007

abstract – Dental pulps from 45 caries‐free primary or permanent teeth and from 24 carious primary teeth were investigated for presence of mast cells (MC). All the pulps were removed from split teeth and fixed in Newcomer's fluid or lead acetate‐formalin. Serial sections stained with hematoxylin‐eosin, astra blue (pH 0.2–0.3) + nuclear fast red, and toluidine blue (pH 1.0) demonstrated that pulps without inflammatory cells or with a few small lymphocytes were devoid of typical MC, even in the strongly metachromatic regions. However, MC were noted in all inflamed pulps; the number, distribution, and appearance of the MC depending upon the severity and type of the inflammatory reaction.
The plaque‐removing effect of four toothbrushing methods
Authors: HANSEN FRODE , GJERMO PER
Published: October 2007

abstract – Two experimental studies were carried out to compare the plaque‐removing ability of three well‐known tooth‐brushing methods (the roll, the horizontal scrub, and Charters') and brushing with a singletufted brush, the interbrush method. After withdrawal of all oral hygiene measures for three days, the teeth were brushed by a dental hygienist employing one of the methods in each quadrant of the mouth. The brushing was performed with brushes recommended for the different methods. Immediately after the brushing, the remaining plaque was assessed according to the Plaque Index. The brushing methods tested showed negligible effect on interdental plaque accumulations. This was valid both in dental students with healthy periodontal conditions and in periodontally treated persons. Vestibularly and lingually more plaque was left after brushing with the roll method than after brushing with any of the other methods. The differences between the horizontal scrub, the Charters', and the interbrush methods were small. Time studies revealed that the horizontal scrub was the least time‐consuming method. The roll method required a little more time, but less than Charters’method, whereas the interbrush method was more time‐consuming than any of the other methods tested.
Incisional wounds in palatal epithelium in guinea pigs
Authors: FEJERSKOV O. , PHILIPSEN H. P.
Published: October 2007

abstract – Standardized incisional wounds were made in the palatal mucosa of 54 adult, male guinea pigs, in order to study the reaction to injury of orthokeratinized epithelium. The wound area was studied histologically 2, 4, 6, 12, 24, 48, 72, 120, and 240 hours postoperatively. Initial cellular changes occurred as early as 2 hours after wounding. The changes consisted of a reduced cytoplasmic stainability with pyknosis and karyorrhexis covering a triangular zone (reactive zone) along the incisional cleft involving the lower part of stratum corneum, stratum granulosum, and the upper half of stratum spinosum. It is suggested that this cellular reaction represents an “induced keratinization”. After 6 hours the reactive zone was delineated from the adjacent, normal epithelial cells by a demarcation zone consisting of 2–3 layers of hyperchromatic, elongated cells. The first signs of migratory activity were noticed from the basal and lower spinous cells 12 hours after wounding. Eighteen hours postoperatively a fusion of the horizontally migrating epithelium had occurred in all wounds examined. By 18 and 24 hours the demarcation zones of the two wound margins met and formed a continuous zone at the base of the incision to constitute the superficial cell layers of the fusion area. A gradual increase in number of cell layers was seen in the fusion area from 24 hours onwards, reaching normal height and differentiation of the epithelium at 120 hours. During the same period epithelial cells migrated from the basal cells into the fibrin‐filled connective tissue wound. By 240 hours the migratory activity was reduced to focal single cell migration. Although a normal cellular differentiation was present in the epithelium of the wound area at 240 hours, the characteristic histo‐architectural pattern of the area had not yet been re‐established, and no PAS‐positive basement membrane was found.
Rate of apposition of maxillary incisor dentin in normal male white rats
Authors: AHLGREN SVEN‐ARNE , HANSSON LARS INGVAR
Published: October 2007

abstract – The rate of normal incisor dentin formation was investigated in 10 adult and 30 young, male Sprague‐Dawley rats. A regular, not earlier described, variation was found and the results were in conformity with those found earlier in female rats. The rate of dentin apposition increases to reach a maximum after which it decreases. This variation is correlated to the age of the odontoblasts.
Duration of swallowing with and without anesthesia of the temporomandibular joints
Authors: INGERVALL B. , BRATT C. M. , CARLSSON G. E. , HELKIMO M. , LANTZ B.
Published: October 2007

abstract – The duration of swallowing and the duration of the movement of the hyoid bone during swallowing was studied cineradiographically in 10 female volunteers, aged 19–24 years. Comparisons were made between the times of various stages of the act of swallowing of watery barium and viscous barium before and during anesthesia of the temporomandibular joints. Anesthesia had no effect on the duration of swallowing or of the movements of the hyoid bone. The median duration of swallowing and of the movements of the hyoid bone was longer for viscous barium (approx. 2.3 s) than for watery barium (approx. 1.6 s). The interindividual variation of the duration of swallowing and of the movements of the hyoid bone was wide. On the other hand, the ranking of the experimental subjects according to the duration of swallowing and the duration of movement of the hyoid bone was fairly constant in all of the recorded swallowings.
A further testing of the effect of dental materials on growth and adhesion of animal cells in vitro
Authors: HELGELAND KRISTEN , LEIRSKAR JAKOB
Published: October 2007

abstract – Human epithelial cells (NCTC 2544) were cultivated in plastic Petri dishes containing disks of dental materials. The effect of the materials on cell growth around and on the surface of the disks was estimated by cell counts. The amount of glucose utilized and lactate formed in the culture media was measured and related to cell growth. In the presence of gold alloy no effect was found. By cell counts a toxic effect was observed on the surface of QC‐20® and Biodent® (heat‐cured acrylics). Around the disks, however, cell growth was not affected. In cultures with silicate cement, Addent 12®, silver amalgam, and copper amalgam, cell growth was inhibited both around and on the surface of the disks, the effect being most pronounced with the two amalgams. Discrepancies observed between cell counts and the metabolic parameters indicate that the latter should be used with caution when evaluating relative toxicities of dental materials.
The effect of roentgen irradiation on the formation of enamel and dentin in maxillary rat incisors
Authors: LINDVALL ANN‐MARIE , OMNELL KARL‐ÅKE , SCHILDT BO E.
Published: October 2007

abstract – An investigation of roentgen‐ray induced enamel and dentin changes in the maxillary incisor in the rat was undertaken to assess the relative radiosensitivity of amelogenesis and dentinogenesis. Seventy Sprague‐Dawley rats received whole body irradiation with exposures between 500 and 950 rad. Five animals served as controls. During the experimental period all the animals were given an injection of oxytetracycline. The animals were killed 5–21 d after irradiation. Ground sagittal sections of the incisors were examined microradiographically and with fluorescence microscopy. The irradiation produced elongated external hypoplastic lesions in the enamel and niches in the dentin. The extent of the lesions varied with the radiation dose. The variation in the extent and appearance of the lesions was much greater in the dentin than in the enamel. Even the smallest dose regularly produced changes in the enamel but seldom in the dentin. Amelogenesis thus proved to be more radiosensitive than dentinogenesis.
Effects of denture washings in chlorhexidine on lactate dehydrogenase isoenzymes in oral mucosa
Authors: FREDÉN H. , HEYDEN G. , WIDMALM S.‐E.
Published: October 2007

abstract – Changes in metabolism in the oral mucosa under acrylic dentures have been studied by gel electrophoresis of lactate dehydrogenase (LDH)‐isoenzymes before and after a simple washing procedure of the dentures in 2.2 mM chlorhexidine gluconate. The clinica data of decreasing inflammation were consistent with the biochemical results of normalization of the LDH‐isoenzyme pattern. The effects of chlorhexidine have been discussed with respect to the affinity of the antibacterial agent to the organic material on the dentures and to the acrylic base material.
Effect of extreme calcium deprivation on degree of mineralization of alveolar bone, dentin and enamel in rats
Authors: RASMUSSEN PER
Published: October 2007

abstract – The effect of an extreme and prolonged calcium‐depriving regimen on the degree of mineralization of alveolar bone, dentin and enamel in adult female rats has been studied by quantitative microradiography. This method is considered to be the method of choice for disclosing differences in V% hydroxyapatite (HA). Despite the calcium‐depriving regimen causing a substantial loss of bone mineral from femur and tibia, as estimated by gravimetric methods, the mineral content of alveolar bone, expressed as V% HA, did not deviate significantly from the normal, indicating that no osteolytic processes had taken place. Neither did the degree of mineralization of the fully formed molar dentin deviate from the normal. However, dentin and enamel formed during the experimental period by the continuously growing incisors disclosed a degree of mineralization which was significantly lower than normal. It was further noticed that the mineral content of the lingual dentin of the incisors, from both experimental and control animals, was significantly lower than the labial dentin.
Sodium and potassium content of the extracellular phase of plaque modified by sucrose and bicarbonate‐phosphate and fluoride
Authors: TURTOLA L. O. , LUOMA H.
Published: October 2007

abstract – Plaque was grown for 3d by caries‐active and caries‐inactive subjects during a daily consumption of 10 tablets made of sucrose, sucrose with a 3% addition of NaHCO3+ KH2PO4 combination (mole ratio 9.82/1), the same with 10 parts/106 fluoride as NaF in the sucrose or sucrose with 10 parts/106 F. Plaque samples were obtained before, during and after ingestion of these tablets. The extracellular sodium and potassium contents of the plaque, calculated against the nitrogen of the plaque material, exhibited changes which were in part attributable to the activation of the plaque organisms during fermentation of sucrose or to inhibition exerted by the additives, in particular by the fluoride. The sodium values suggested that it was diffusing into the plaque.
An electron microscopic study of tetracycline‐induced enamel defects in rat incisor enamel
Authors: NYLEN MARIE U. , OMNELL KARL‐ÅKE , LÖFGREN CLAES‐GÖRAN
Published: October 2007

abstract – The structure of incremental bands and gross hypoplastic lesions in rat incisor enamel which resulted from single or multiple injections with tetracycline hydrochloride was studied in the electron microscope. Both types of lesions which were investigated previously using microradiography and fluorescence microscopy exhibited many unusual structural features which are discussed in relation to current concepts of normal enamel formation. Disturbances in packing and organization were common to all the lesions indicating a primary interference with the first phase of enamel formation, i.e. matrix formation and initial mineralization. These changes were the main cause of the various mineralization disturbances seen in the microradiograms. Temporary and permanent interference with the second or maturation phase, i.e. crystal growth, was also evident but only as a corollary to the principal disturbance. This, and other evidence, suggests that tetracycline as well as many other chemical agents achieve their principal effects on enamel formation by injuring pre‐secretory or secretory ameloblasts. Thus it appears that most developmental mineralization disturbances are symptomatic of hypoplastic lesions or are a sequela to the cell injury which also causes the hypoplastic lesions. Because of that it is suggested · that commonly used division between hypoplastic and hypomineralized defects be abandoned.
The load dependence in micro indentation hardness testing of enamel and dentin
Authors: HEGDAHL TROND , HAGEBÖ TORUNN
Published: October 2007

abstract – The load dependence of Vickers micro indentation hardness values of enamel and dentin has been determined. A significant, but slight variation in hardness was obtained when the load was varied within the range of practical applicability. An increase in load implies an increase in the hardness of enamel and a decrease in the hardness of dentin.
The use of colchicine for the assessment of mitotic activity in rat oral epithelium
Authors: KARRING T. , LÖE HARALD
Published: October 2007

abstract – Groups of white albino rats were used in this study. Serial sections were prepared of the hard and soft palate, tongue, cheek, gingiva, cornea and ear, and were stained with hematoxylin and eosin. Mitotic counts in tongue epithelium of nine groups of rats which received various colchicine dosages (0 to 3 mg/kg body weight) and were sacrificed 3½ h later showed that 1 mg colchicine per kg body weight is the optimal dosage for studying the mitotic activity in rat oral epithelium. Mitotic counts in six other groups of rats sacrificed at different times (0 to 50 min) after the administration of colchicine indicated that the colchicine takes effect 25–30 min after the injection. The pattern of diurnal variation in mitotic activity was determined in the ear and various oral epithelia using eight groups of colchicinized rats. A fairly high correlation was found between the daily mitotic rates and the mitotic rates obtained during the maximum mitotic activity. There was a low correlation between the daily mitotic rates and turnover times indicating that calculations of turnover time may fail to express the mitotic activity of the epithelium. Mitotic counts for various sites of the hard palate, tongue and cheek in seven rats indicated that the mitotic activity may vary from one region to another within the individual tissue.
The importance of zinc to cell proliferation in endochondral growth sites in the white rat
Authors: BERGMAN BO , FRIBERG ULF , LOHMANDER STEFAN , ÖBERG TORSTEN
Published: October 2007

abstract – The possible importance of zinc to cell proliferation in endochondral growth sites in the white rat was studied using zinc‐deficient feeding and light microscopic autoradiography with tritiated thymidine. Eight experimental rats were given a zinc‐deficient diet ad libitum and eight paired‐fed controls were given the same diet plus zinc supplement. After 3 weeks on the experimental diet, at which time the animals were 6 weeks old, they were injected with H3‐thymidine. Two rats from each group were killed after 1 h, and 1, 3 and 6 d. Tissue specimens were taken from the mandibular condyle, the proximal epiphysis of the humerus and the costo‐chondral junction of the rib. The autoradiographs indicated a reduction, as compared to the control rats, of cell proliferation in the three endochondral growth areas in the experimental rats.
In vitro incorporation of tritiated thymidine in oral homogeneous leukoplakias
Authors: ALVARES O. , SKOUGAARD M. R. , PINDBORG J. J. , ROED‐PETERSEN B.
Published: October 2007

abstract – The rate of cell proliferation in homogeneous leukoplakias was compared with that of normal mucosa. Biopsies from six patients were labeled in vitro with tritiated thymidine and the labeling indices relative to (1) the total cell population, (2) the progenitor compartment, and (3) 100 μm surface length, were determined on autoradiographs. In leukoplakias, cell renewal and mitotic cycles were faster than in the epithelium of controls.
Fluoride release by silicate cements and composite resins
Authors: FORSTEN LENNART , PAUNIO ILKKA K.
Published: October 2007

abstract – The purpose of the study was to determine the fluoride content of acrylic and composite resins and to study the release of fluoride from these materials in comparison to the release from silicates. The analytical results showed that one composite contained approximately the same amount of fluoride as is generally reported for silicates. The other resins contained none or only minimal amounts of fluoride. The release of fluoride was studied by measuring the uptake of fluoride by synthetic hydroxylapatite. Rectangular test specimens, 2 × 2 × 12 mm, made of the fluoride‐containing resin were shaken in a neutral (pH 6.8) and an acidic (pH 5.8) solution with the hydroxylapatite for 7 weeks. The apatite was analyzed for fluoride each week and the test specimens were then transferred to a fresh solution with new apatite. As a control, a composite without fluoride was studied in the same way. For comparison two silicate cements were also included in the study. The results show that, during the first week, the uptake of fluoride by the apatite was greater from the silicates than it was from the composite. After that period the uptake continued at a lower level and did not show any marked decrease during the observation period. This continued uptake was about the same from both the silicates and the composite.
Acidic glycosaminoglucuronoglycans of human tooth germs
Authors: MATTHIESSEN M. E. , HELIN G.
Published: October 2007

abstract – The acidic glycosaminoglucuronoglycans in germs of primary teeth from three human fetuses have been isolated and identified. The biochemical analysis revealed the presence of hyaluronic acid and chondroitin‐4‐suIfate and/or chondroitin‐6‐sulfate while dermatan sulfate and heparan sulfate were not demonstrated.
Acid mucopolysaccharides in monkey and human pulps
Authors: STENVIK A. , SKOGEDAL O.
Published: October 2007

abstract— Different fixation and deminerahzation methods were used in combination with fresh frozen and paraffin embedded pulps from 60 human and 23 monkey teeth. Alcian blue and azure A staining revealed acid mucopolysaccharides in granular and nongranular forms in both monkey and human pulps. The nongranular material was confined to the apical area and appeared similar in both species. Granules were found only along fiber bundles in the human pulp, whereas in monkey pulp, granules were located intracellularly in the subodontoblastic area and extracellularly in the middle part of the pulp. The mucopolysaccharides were classified according to their sensitivity to hyaluronidase and neuraminidase, and to their staining at varying pH‐values. Paraffin embedded sections of shelled out pulps yielded the best information of acid mucopolysaccharide distribution.
Histomorphologic investigations on the effect of cyclophosphamide on dentinogenesis of the rat incisor
Authors: KOPPANG HANNA STRöMME
Published: October 2007

abstract— Cyclophosphamide in doses of 25, 50, 75. 100, 125, and 150 mg/kg was administered to 60 rats in 6 groups. Histomorphologic investigations of maxillary and mandibular incisors two weeks later revealed the following dose‐dependent reactions: (1) interruped odontogenesis, (2) circular and mesio‐distal dental constrictions, (3) niche‐like dentinal defects, (4) differentiation of a postexperimental tooth, and (5) cyst formation and circulatory disturbances. Differences were observed in the frequencies of lesions in maxillary and mandibular incisors, and between labial and lingual aspects of the teeth. The results were related to roentgen irradiation effects, with which they largely concur
Autoradiographic investigations on the effect of cyclophosphamide on dentinogenesis of the rat incisor
Authors: KOPPANG HANNA STRöMME
Published: October 2007

abstract— Five μCi 3H‐glycine/g bodyweight were administered to 10 rats 30 min prior to, and to 10 rats 24 h after 25 or 40 mg/kg of cyclophosphamide. Fourteen rats served as control material. Autoradiographic investigations of the incisors demonstrated the preodontoblasts to be the odontoblast developmental stage most sensitive to cyclophosphamide, succeeded by precursors of preodontoblasts. The injury was reflected as a reduced production of circumpulpal dentin. The sensitive period was approximately equivalent to maximally 48 h, minimally 24 h. The results were discussed in relation to those obtained with roentgen rays.
Alkaline phosphatase in the enamel organ of the rat incisor
Authors: FREDÉN H , GRANSTRöM G. , LINDE A.
Published: October 2007

abstract—The distribution of alkaline phosphatase in the enamel organ of the rat incisor was histochemically investigated using α‐naphthyl phosphate as the substrate. During the stage of enamel matrix formation the enzyme activity was found mainly in the stratum intermedium, while during the stage of enamel maturation the activity was evenly distributed within the enamel organ. The biochemical properties of alkaline phosphatase, using paranitrophenyl phosphate as the substrate, were studied. The pH optimum of the enzyme was found to be about 10. The heat inactivation of alkaline phosphatase from the enamel organ was found to be similar to the behavior of bone and odontoblast phosphatase. Mg2+activated the enzyme, while Ca2+, PO43−and F−inhibited the enzyme. The effect of urea on the enzyme activity was similar to the behavior of bone and odontoblast phosphatase. EDTA treatment resulted in a marked inhibition of the activity of alkaline phosphatase. It was concluded that there was no detectable difference in biochemical behavior between alkaline phosphatase in the stage of matrix formation and the stage of enamel maturation. It was also concluded that alkaline phosphatase from the enamel organ is similar to the alkaline phosphatase from bone and odontoblasts.
Activity and distribution of acid phosphatase in zinc‐deficient parakeratotic rat buccal epithelium
Authors: ALVARES O. F. , MEYER J. , GERSON S. J.
Published: October 2007

abstract— Weanling rats were fed a diet containing 1.3 mg zinc/kg diet and controls the same diet supplemented by 40 mg zinc/kg diet. After 28 d on this dietary regime, the buccal epithelium of experimental animals showed increased thickness and parakeratosis. The activity and distribution of acid phosphatase were studied in buccal epithelium employing α‐naphthol phosphate as substrate for quantitative and slide histochemical techniques. The ultramicro assays showed that acid phosphatase activity increased by about 70% each in cellular and keratin layers of experimental animals. The sections showed that beginning in the lower spinous cells of experimental animals, reaction product was greatly increased at the cell periphery, but greatly decreased in the cell interior. It is suggested that increased enzyme activity reflects the hypertrophic response in the buccal epithelium of zinc‐deficient animals. Peripheral displacement of reaction product is unexplained, but diminished activity in the cell interior could account for parakeratosis and the persistence of cytoplasmic organelles in the keratin layer.
Fluoride release from varnish‐coated silicates and from cavity liners and fissure sealants
Authors: FORSTEN LENNART , PAUNIO ILKKA K.
Published: October 2007

abstract— The fluoride release of varnish‐coated silicates and liners and sealants was studied by measuring the uptake of the released fluoride by synthetic hydroxyapatite. Silicate specimens were made and coated with cavity varnish. The specimens were shaken in solution with the apatite for 7 weeks. The apatite was analyzed for fluoride each week and the specimens were then transferred to a fresh solution with new apatite. The varnish reduced the fluoride release during the first three weeks, but after that time the release from the varnish‐coated specimens was the same as that from the uncoated specimens. The release from the liners and sealants was studied by coating composite resin specimens with the material. The resin contained no fluoride. The specimens were shaken in solution with apatite and the fluoride uptake was measured each week in the same manner as for the silicate specimens. The liners showed an initial release of fluoride. When the two different sealants were applied as two layers, only one of the brands showed initial release of fluoride. Five layers of sealant resulted in an initial release from both brands.
Residual mercury and amalgam quantity in conventional and wet techniques
Authors: BERGDAHL GUNHILD
Published: October 2007

abstract— Twenty‐six amalgam restorations were performed using the conventional amalgam technique, and 26 using the wet amalgam technique on the same Class II cavity model. For the marginal proximal areas the mean difference in residual mercury content between the two techniques was 5.0% and for the remainder of the restoration 3.6%. The wet technique required, on an average, 58% more amalgam than did the conventional technique. The differences between the two techniques were statistically significant (P<0.001).
A comparative study of demineralization of enamél evaluated by means of 32P uptake and calcium release
Authors: MÖRCH T. , PLASSCHAERT A. J. M.
Published: October 2007

abstract – The degree of demineralization of the enamel surface was evaluated by means of two different methods, namely by the 32P uptake method, and by determining the calcium release directly, using atomic absorption spectroscopy. The accuracy of the 32P uptake method was assessed. When applied on groups of young and old premolars separately, the 32P uptake method proved to give reliable information about differences between the two groups with respect to the degree of demineralization under equal experimental conditions. For comparison the two methods were used simultaneously in 20 separate tests with varying experimental conditions. The comparison of the results obtained by the two methods showed very good correspondence.
Enzyme activities in the isolated enamel organ from the rat incisor during the two main stages of amelogenesis
Authors: FREDEN HAKAN
Published: October 2007

abstract – The enamel organ from the rat incisor was dissected out. The amount of connective tissue in the samples was checked by light microscopy. Samples representative of the stage of enamel matrix formation and of enamel maturation were taken and the activities of the following enzymes were estimated: aldolase, pyruvate kinase, lactate dehydrogenase, malate dehydrogenase, glucose‐6‐phosphate dehydrogenase and alkaline phosphatase. The enzyme activities were related to the amount of tissue protein and the amount of DNA. All the enzymes, except alkaline phosphatase, showed an increase in measured activity during the stage of enamel maturation. The significance of these changes in in vitro activities is discussed.
Ultrastructural observations on human coronal dentin
Authors: TRONSTAD LEIF
Published: October 2007

abstract – The incisal area of the coronal dentin of intact anterior teeth was studied by means of scanning and transmission electron microscopy. The great majority of the tubules were open regardless of age. A variety of fibrous structures with diameters between 50 nm and 0.7 μm were observed within dentinal tubules. The cross‐banding typical of collagen was occasionally discernible in these fibers, but as a rule they had a smooth surface, probably due to masking of structural details by ground substance. Fibers with a tendency to arboresce were interpreted as nerve fibers. Disturbances in the mineralization were observed in a central area of the dentin between the pulp horn and the incisal edge. Especially the development of peritubular dentin was inconsistent. In adult teeth the tubules at this location were occluded by a fine‐textured material. A varying amount of secondary dentin was present in the pulp horn of the teeth at an early age. The first formed tissue had an atubular appearance, whereas in an apical direction the structure became more regular with tubules and intertubular areas.
Perfusion fixation of rat molar pulp tissue for light microscopy
Authors: HEIDE SYNNÖVE
Published: October 2007

abstract – Molar pulp tissue of 42 rats was subjected to cardiac perfusion fixation or to immersion fixation with glutaraldehyde and formaldehyde. The importance of variations in pressure and duration of cardiac perfusion was studied. The results indicated that the perfusion method was superior to immersion fixation. Best preservation of the tissues was obtained when perfusion was performed with 1.7% glutaraldehyde for 10–12 min under a pressure of 130 cmH2O, and leaving the animals for 4 h, without immersion fixation. Also perfusion with formaldehyde resulted in good preservation, provided the solutions were prepared from paraformaldehyde powder. In contrast, solutions made from commercial stock solutions of formaldehyde gave inferior results. For sections stained with hematoxylin‐eosin, perfusion with glutaraldehyde was preferable, while perfusion with formaldehyde showed increased sensitivity in demonstration of dentinal tubules stained with alcian blue at pH 3.6. It is suggested that in future studies on rat pulp tissue, perfusion with glutaraldehyde and formaldehyde should replace immersion fixation.
Cytochemical demonstration of adenyl cyclase in rat incisor enamel organ
Authors: MöRNSTAD H. , SUNDSTRöM B.
Published: October 2007

abstract— With adenylyl‐imidodiphosphate as a specific substrate, adenyl cyclase has been demonstrated at the plasma membranes of all epithelial cells except the ameloblasts in the enamel organ of rat incisors. Hydrolysis of the substrate was found to be stimulated by 10 mM sodium fluoride in the incubation medium.
Fluoride contents of surface enamel in high‐ and low‐fluoride areas studied with a sensitive physical method
Authors: RYTöMAA I. , KLEEMOLA‐KUJALA E. , KEINONEN J. , ANTTILA A.
Published: October 2007

abstract— Fluoride content was measured with a sensitive physical method in the enamel of the four smooth surfaces of 12 primary and 12 permanent teeth from areas with drinking water of high‐ and low‐fluoride content. In the high‐fluoride area (1.9 parts/106 in drinking water) the average fluoride content of the surface enamel was 1,826 parts/106 and in the low‐fluoride area (0.05 parts/106. Permanent teeth contained about 20% more fluoride than primary teeth. In two children in the low‐fluoride area the fluoride content of the enamel was exceptionally high in the vestibular surface, presumably owing to local application of fluorides.
Permeability of different lining materials
Authors: ERIKSEN HARALD M. , NORDBÖ HÅKON
Published: October 2007

abstract— The permeability of four dental lining materials has been tested by water vapor penetration in vitro. Films of Dycal® and Copalite® were found to have low permeability values while rather great permeability was found for test specimens of Dropsin® and Tubulitec®.
The effect of silicate cement on enamel and dentin
Authors: GRIEVE A. R.
Published: October 2007

abstract— The effects upon enamel and dentin of mixes of two different viscosities of silicate cement were examined by polarized light microscopy and microradiography. The silicate was applied to the cut surfaces of extracted teeth for periods of time ranging from 1 h to 2 weeks. In a few cases a very slight degree of demineralization of enamel occurred. Surface demineralization of the dentin, however, was observed in all specimens. This zone of demineralization in the dentin was widest centrally over the pulp and narrowed peripherally towards the amelodentinal junction. A zone of increased mineralization was observed underlying the demineralized area. The fluid mix of silicate resulted in more rapid loss of mineral than did the more viscous mix, but in neither case did the extent of demineralization appear to increase after the first 24 h. In a number of cases, especially those to which the fluid mix had been applied for 24 h, a subsurface zone of demineralization was also observed in the dentin.
Discrepancy between objective and subjective profile measures
Authors: GIDDON D. B. , HERSHON L. E. , LENNARTSSON B.
Published: October 2007

abstract— As a part of an overall project to develop an index of “psychologic need” for orthodontic treatment, a method was devised to determine how accurately one perceives his own profile. In a preliminary study, 21 unselected Swedish females (Ss), aged 18 to 30, were asked to recreate their own and desired profiles from three adjustable cardboard pieces representing the nose, upper lip, and lower lip/chin. Angular and linear measurements were obtained from soft tissue profile landmarks of cephalometric tracings. To discern differences in perceptual‐motor ability, and to provide practice in manipulating the device, each S performed replicated simulation of an idealized test profile. A semantic differential self‐evaluation of attractiveness of each facial feature was also completed for comparison with subjective and subjective‐objective discrepancy measures. The results indicated that Ss differed in their ability to recreate their own profiles as a function of some combination of intervening psychologic, perceptual, or motor variables. In general, Ss underestimated less desirable features. The significant correlations between simulation measures of one's own and desired profiles, and between the simulation of desired profile and idealized test figure suggested the Ss were satisfied with their own appearance and/or were more influenced by the idealized test profile.
A histochemical study of temporal muscle fibers in denture wearers and subjects with natural dentition
Authors: RINGQVIST MARGARETA
Published: October 2007

ABSTRACT – Biopsy specimens from temporal muscle of denture wearers and subjects with natural dentition were studied by biochemical staining methods. Size and distribution of fiber types were estimated in sections stained for myofibrillar ATPase at pH 9.4. The mean sizes of Type 1,* Type 2 and intermediate fibers in denture wearers did not differ from those of the corresponding types of fibers in subjects with natural dentition. In the denture series. Type 2 fibers were smaller in subjects who rated their dentures as deficient than they were in those whose dentures were good. The frequency of intermediate fibers was low in both series. The mean percentage distribution of Type 2 fibers in specimens from the internal surface of the temporal muscle was significantly lower in the denture series than in the specimens from subjects with natural dentition. It is suggested that the low content of Type 2 fibers in the specimens from the internal surface of the temporal muscle of denture wearers and the small size of Type 2 fibers in subjects who rated their dentures as deficient may be attributed to altered functional demands.
Deposits of immunoglobulins and complement in oral lupus erythematosus
Authors: SCHIÖDT M. , DABELSTEEN E. , ULLMAN S. , HALBERG P.
Published: October 2007

ABSTRACT – Deposits of immunoglobnlins were demonstrated at the basement membrane zone in oral lesions in 10 out of 11 patients with lupus erythematosus (LE), and in normal oral mucosa in one out of six patients with LE by means of an imniunofluorescence staining technique. The reported findings are in accordance with the findings in skin biopsies from cutaneous LE lesions. In cases of LE, difficult to diagnose clinically and histopathologically, the imniunofluorescence staining technique may be of value as a supplementary diagnostic tool.
Biologic effect of poiyisobutylene on bony tissue in guinea pigs
Authors: BERGDAHL MARGRETH , WENNBERG ALF , SPÅNGBERG LARZ
Published: October 2007

ABSTRACT – Polyisobutylene (Oppanol B®) is an adhesive resin which may be suitable in endodontics. The reaction of bony tissue to Oppanol B was assessed by implanting the material into the mandible of guinea pigs. The results indicated that Oppanol B was well tolerated by bony tissue and showed a better tissue compatibility than the root filling malerial AH26®.
Effect of 2‐years' use of chlorhexidine‐containing dentifrices on plaque, gingivitis, and caries
Authors: JOHANSEN JAN R. , GJERMO PER , ERIKSEN HARALD M.
Published: October 2007

abstract— Chlorhexidine digluconate in 0.1% and 0.4% concentrations was added to dentifrices to evaluate its effect on plaque formation, gingival conditions and caries in 73 dental students over a 2‐year period. No differences were found in the P1 I and the G I indices between the active and the placebo dentifrices, but a possible effect on caries was demonstrated. Discolorations of anterior teeth and fillings were the only side effects observed.
Trypsin activation of latent collagenase from several mammalian sources
Authors: BIRKEDAL‐HANSEN HENNING , COBB CHARLES M. , TAYLOR ROBERT E. , FULLMER HAROLD M.
Published: October 2007

abstract— Latent collagenase, subject to activation by trypsin, was found in culture fluids of cells and tissues from several mammalian sources. The activation requires exposure to enzymatically active trypsin and cannot be achieved by inhibited or by heat‐inactivated trypsin.
The stoichiometric solubility of calcium orthophosphates
Authors: HAGEN ARNE R.
Published: October 2007

abstract— On the assumption that the calcium orthophosphates dissolve stoichiometrically, the solubility of Hap, Fap, DCPD, OCP and TCP, as well as of CaCO3 and CaF2, have been calculated in terms of grams of solid phase per liter under equilibrium conditions. As exemplified in the text, these calculated solubilities facilitate the understanding of the complex behavior of the orthophosphates when in solution.
Repair characteristics of root fractures in permanent anterior teeth
Authors: JACOBSEN INGEBORG , ZACHRISSON BJÖRN U.
Published: October 2007

abstract— A follow‐up study was made of repaired root fractures in 51 permanent anterior teeth, with a mean observation period of 6 years. The material was subdivided into three repair types (Figs. 1–3): Type 1—invisible or hardly discernible fracture line (15 teeth), Type 2—fragments separated by a narrow radiolucent line and peripheral rounding of the fracture edges (33 teeth), and Type 3—fragments separated by a distinct bony bridge (3 teeth). The majority of repaired teeth gave a normal or slightly decreased response to electric pulp tests and the mobility was physiologic or slightly increased. Reduced transparency or slight yellowish discoloration was observed in 14 teeth. The most conspicuous radiographic finding was pulp obliteration which occurred in 86%. Two different patterns were observed: (1) partial obliteration located in the apical fragments and the fracture area, and extending 0.5–4 mm into the coronal fragment, and (2) progressive obliteration of the entire pulp cavity ending with almost total obliteration. Pulp necrosis did not develop as a sequel to progressive obliteration in any case. Several different characteristics of the fracture influenced the repair pattern, the most important being the degree of fragment dislocation and mobility, stage of root development and localization of the fracture. Correlation between type of repair and various treatment procedures was observed only with regard to reduction.
Assessment of denture plaque pH in subjects with and without denture stomatitis
Authors: OLSEN INGAR , BIRKELAND JAN MAGNE
Published: October 2007

abstract— To evaluate the “resting” pH and induced pH changes in denture plaque, soft deposits were collected from the fitting surface of the denture, pooled and suspended in water. Plaque pH was determined with microelectrode equipment before and after mouth rinsing with a sucrose solution. A characteristic level in the “resting” pH of denture plaque was found in most of 12 subjects tested. pH values below the baseline level were recorded for more than 2 h after a rinse. The pH depressions were more pronounced in maxillary than in mandibular plaque. Further, the pH minima tended to be lower in subjects with denture stomatitis than in. controls. No clear relationship could be established between the “resting” pH and the concentration of Candida hyphae in denture smears or palatal inflammation.
Occlusion in the primary déntition in 3‐year‐old children
Authors: RAVN J. J.
Published: October 2007

abstract – The material for the present study comprises plaster models of 310 Copenhagen children, impressions for which were taken during the month each child attained the age of 3 years. On the basis of fixed criteria a description is given of individual symptoms of occlusion. Using the primary canines as the guide to occlusion it was found that the same occlusion at both sides occurs in 79.7 % of the overall total, the remaining 20.3 % having different occlusion at each side. Approximately one‐half recorded neutral occlusion at both sides, and one‐third had distal occlusion at both sides. The termination pattern of the dental arches in centric occlusion were normal or straight in 68.0 % and bilateral distal in 14.8 %. In 82 subjects or 27 % the degree of overlapping was greater than or equal to half the height of the mandibular central incisors. The number of cross‐bites constituted 11.6% of all subjects. Assessment of spacing was undertaken exclusively on the basis of whether or not a space existed. About 3.5 % of all subjects had close contact between all teeth in the maxilla or crowding, and about 24 % had spacing between all teeth in the maxilla. In the mandible about 5 % had close contact between the teeth and only 15 % had spacing between all teeth in the mandible.