bluuebunny/crossref_metadata_2025 huggingface dataset:
An example of the importance of experimental design and statistical analysis in dental research
Authors: Bandt Carl L. , Stallard Richard E.
Published: June 2006

In this paper a specific dental investigation was used to demonstrate the value of several statistical principles. It was concluded that:

Blind evaluation of tissues is important in preventing bias in interpreting the histomorphologic results.

The loss of replication makes it impossible to evaluate the effect of sacrifice time on radioautographic labeling.

A probability value P = .12 can be of interest if one understands the data to which it is applied (i.e. P = .01 or P = .05 is not sacred).

Investigator inconsistency exists and should he considered. In this case evaluating the tissues in a random order averages out the effect of counting fewer labeled cells as the evaluation progressed.

Random allocation of animals to control and experimental groups eliminates the possibility of bias in allocation. The smaller size of the experimental animals is not, therefore, a function of allocation.
Changes in microcirculation after local application of sex hormones
Authors: Lindhe Jan , Brånemark P. I.
Published: June 2006

The invariable occurrence of gingivitis in pregnancy initiated the present study of the local effects of sex hormones, deposited in the tissues. Vital microscopic studies of hamster's cheek pouch disclosed varying degrees of tissue injury manifested by mierocirculatory disturbances and related to the type and concentration of the hormones Gonadex®, Ovex‐B®, Stilbol® and Progesteron®. There were changes in blood flow, the behaviour of cells in the vessels and in the vessel walls and in the perivascular mast cells. Some of these abnormalities were reversible whereas others were permanent and severe.
Tooth mobility changes in pregnancy
Authors: Rateitschak Klaus H.
Published: June 2006

Horizontal tooth mobility of the upper incisors was repeatedly measured with the macroperiodontometer in 7 subjects during pregnancy and until several months after delivery. In 6 periodontally healthy females, a small but statistically significant average change in mobility was found. Mobility was highest during the last month of pregnancy. One subject with moderate symptoms of periodontitis and with pathological mobility exhibited a pronounced mobility increase which, 6 months post partum, had not returned to the levels determined at the third month of pregnancy. Increase of mobility during pregnancy was apparently caused by alterations of the periodontal membrane and not of the alveolar socket bone.
Programmed self‐instruction in oral hygiene
Authors: Bratthall Douglas
Published: June 2006

The aim of this investigation was to study whether programmed self‐instruction in oral hygiene, given once, could increase the subject's knowledge and also whether this resulted in more effective oral hygiene as measured by the accumulation of dental plaque and the state of the gingivae. The investigation was performed on recruits to the Armed Services. Using questionaires, it was estimated whether knowledge about oral hygiene was increased and retained. By estimating plaque formation and gingival health it was determined whether oral hygiene was improved. The self‐instruction programme contained 42 frames and was presented in the form of a book. It was read by the experimental groups on a single occasion. The subject's knowledge was tested immediately before and after the self‐instruction, and again after one month. The level of oral hygiene was assessed before the instruction, after one week and again after one month. The subject's knowledge was improved and retained, as estimated from the replies to the questions. The plaque and gingival scores were significantly reduced. The results were achieved with a minimum of time and personnel. Therefore, the method seems to be highly efficient. Due to this and to the fact that it can be adapted for varied purposes, it is concluded that programmed self‐instruction is a valuable method for teaching oral hygiene.
The effect of supervised oral hygiene on the gingivae of children
Authors: Lindhe Jan , Koch Göran
Published: June 2006

The aim of the present investigation was to determine whether careful training in tooth‐brushing had a prolonged effect on the oral hygiene and gingivae of 13‐14 year‐old school‐children. Supervised tooth‐brushing had continued for three years and ended one year before the final gingival and plaque scorings were carried out. A group of children of similar age and from the same school served as controls. The children of the control group had not been subjected to any form of supervised or controlled oral hygiene procedures. The gingival state and oral hygiene were recorded according to index systems proposed by Löe and Silness (1963) and Silness and Löe (1964). The examinations revealed that: During the years of supervised tooth‐brushing, the experimental group had a significantly lower Gingival Index than the control group (GI experimental group 1965: 0.22, 1966: 0.24; GI control group 1965: 0.78, 1966: 0.95). One year after the end of the supervision, the Gingival Index of the experimental group was 0.47. The corresponding index for the control group was 0.66. This difference is not statistically significant. The deterioration of the gingival condition in the experimental group and the improvement in the control group can be explained by the poorer oral hygiene in the experimental group and the improved hygiene in the control group. The fact that the careful training in tooth‐brushing had no prolonged effect on the gingivae indicates that this scheme failed to make the participating children tooth‐minded. Possible reasons for the lack of effectiveness are discussed and improvements suggested.
Changes in vascular permeability after local application of sex hormones
Authors: Lindhe Jan , Brånemark P‐I
Published: June 2006

A previous experimental study by the present authors revealed that microcirculatory disturbances are produced by locally‐applied female sex hormones in the cheek‐pouch of hamsters. On the basis of this, the present study was designed to elucidate possible aberration in microvascular permeability induced by these female sex hormones. The permeability characteristics of the vascular wall were evaluated after intraveneous injections of a protein‐bound dye ‐ Evan's blue ‐ whose leakage into the perivascular tissue was considered to indicate increased permeability. In addition, endothelial damage was assessed by vascular labelling with a carbon‐ink suspension. Estrogens and progesterone, in contrast to chorionic gonadotropin, were found to provoke endothelial damage and increased vascular permeability. These findings agree with the clinical features of pregnancy gingivitis.
Changes in vascular proliferation after local application of sex hormones
Authors: Lindhe Jan , Brånemark P‐I , Lundskcg Jan
Published: June 2006

The effect of locally applied female sex hormones ‐ Gonadex®, Ovex‐B®, Stilbol®, and Progesteron® ‐ on the second phase of inflammation, vascular proliferation, has been explored by micro‐angiography of the micro‐vascular architecture of the rabbit's ear. The estrogens and progesterone stimulated vascular proliferation at the site of a primary micro‐trauma (the injection). Chorionic gonadotropin, however, did not induce any recognizable micro‐vascular proliferation. These findings are discussed in the light of present knowledge of hormonal influence on the gingival tissues.
The implantation of decalcified human dentin and cementum into the subcutaneous tissues of the rat
Authors: Morris Melvin L.
Published: June 2006

The effect of decalcification on the inductive activity of cementum and dentin was tested by implanting decalcified human roots into the subcutaneous tissues of the rat.

No new cementum was seen. The first six months showed marked deep resorption and the second a re‐calcification of the remaining dentin. Decalcification with 5 per cent neutral EDTA destroyed the cementogenetic inductive influence of cementum and dentin previously noted in undecalcified implants.

The theoretical implications of the findings were discussed.
Experimental gingivitis in man
Authors: Löe Harald , Theilade Else , Jensen S. Borglum , SchiØtt C. Rindom
Published: June 2006

During a 5 day period without oral hygiene, 4 groups each consisting of 3 subjects with healthy gingivae, rinsed their mouths with solutions of tetracycline, vancomycin, polymyxin B or distilled water. Gingival plaque accumulated rapidly in the group rinsing with water, while tetracycline, and to a lesser degree vancomycin and polymyxin B inhibited plaque formation. Clinical gingivitis was not observed in any of the participants, but gingival exudate and leukocyte emigration were noted and seen to increase during the experimental period, especially in the water group. Rinsing with antibiotics inhibited these signs of subclinical inflammation to varying degrees. The bacterial composition of the gingival plaque changed in the water group during the experimental period towards a higher percentage of gram‐negative bacteria, following the pattern observed in previous investigations. Tetracycline markedly reduced the numbers of gingival plaque organisms, while polymyxin B favored a proliferation of gram‐positive cocci and short rods and depressed gram‐negative bacteria. Rinsing with vancomycin resulted in a pronounced shift towards an almost pure gram‐negative plaque flora. It is concluded that local administration of antibiotics with a limited spectrum may be useful for the study of the pathogenicity of the different components of the gingival microbial flora.
Gingival tissue physiology in vitro
Authors: Powell R. N.
Published: June 2006

The cultivation in vitro of adult human gingival tissue without cellular de‐differentiation, is possible for periods of up to four days. During this time predictable results are best achieved in the first forty eigth hours. Thereafter epithelial encirclement endangers the vitality of the explant. Studies of gingival tissue physiology in vitro are therefore best carried out during this time interval.
The localization and possible role of esterases in human gingiva
Authors: Cohen Lawrence
Published: June 2006

The distribution of the different esterases was investigated in human gingiva. The α naphthyl acetate method showed increased activity of non‐specific esterase in the region of the granular layer in orthokeratotic gingiva. A similar enzyme distribution was noted with the naphthol AS‐LC method, which suggests that the two methods are demonstrating the same enzyme. The latter method was, however, not as satisfactory as the former due to crystal formationndoxyl acetate esterase activity was also increased in the region of the granular layer. This increased activity seems to indicate that the esteraset are related to cytoplasmic autolysis.
Response of oral epithelia to ovariectomy and estrogen replacement
Authors: Litwack D. , Kennedy J.E. , Zander H.A.
Published: June 2006

Ovariectomies were performed on 8 squirrel monkeys. Four of the animals received 0.1 mg estradiol benzoate intramuscularly 3 times per week for 4 months. One hour prior to sacrifice all animals received H3‐thymidine. Sections of vagina, buccal mucosa and gingiva were processed for hematoxylin and eosin staining and autoradiographs. Measurements were made of the basemined membrane/mm of surface length, the number of basal cells/mm of basement membrane determined and a labeling index for basal cells established.

The animals which had received estradiol benzoate exhibited a thick vaginal epithelium in contrast to the other animals which showed a thin and often ulcerated epithelial covering. The vaginal epithelium of the estrogen treated ovariectomized animals had longer rete pegs, fewer basal cells/mm of basement membrane and a higher labeling index than those animals not receiving estrogen. The epithelium of the buccal mucosa was significantly different in the same direction as the vagina by all three criteria. The gingival epithelium showed no significant differences by two of the three criteria.
Observations on vascular proliferation in a granulation tissue
Authors: Lindhe Jan , Brånemak P‐I
Published: June 2006

The present study was performed in order to study the progressive growth of vessels in a regenerating tissue and to analylze the tissue events occurring outside and inside the mature micro‐vessels immediately before sprout formation. Twenty, 10–20 months old female rabbits, weighing 2–3 kilos each were used. A modified Sandison's ear chamber was installed in each animal. Healing of a tissue defect was studied in a modified Leitz intravital microscope.

Immediately after installation of the ear chamber, the center of the wound was practically devoid of cells. The venules of the bordering tissue showed signs of an acute inflammation. During the first hours there was an obvious leakage from the venules of the bordering tissue of an intravenously injected protein bound dye. Some hours later granular cells started to emigrate from the adjacent pre‐existing venules into the defect space. Six to eight hours after surgery corpuscular and plasma flow was normal in all vessels in the region of the ear chamber. During the next 35–40 hours the protein network became denser. By the end of the second day most of the granular cells of the defect had lost their amoeboid properties. The nucleus and the granules of these cells became denser and more prominent. By 48–72 hours several of the rigid granular cells disintegrated and dispersed their cytoplasmic granules into the defect. A few hours after degranulation the corpuscular flow rate of the bordering vessels increased. Erythrocytes and later granulocytes penetrated the venular walls and entered the extra‐vascular space. In the immediate vicinity of the vertices of the preformed venules, strings of red and white cells moved back and forth apparently creating well defined tubes bordered by a fibrillar structure. The cell movements seemed to open up and elongate the tubes. Between the moving cells and aggregated cells of the defect a layer of thin transparent cells could eventually be detected. In this situation there were also optically definable openings in the walls of the borderline venules and true communicationsestablished between the preexisting vessels and the newly formed.
Light and electron microscopic studies of colloid bodies in lichen planus
Authors: El‐Labban N.G.
Published: June 2006

The nature of Civatte bodies in oral lichen planus lesions of 11 patients was investigated by light and electron microscopy. The results suggested that these bodies were derived from keratinizing epithelial cells which formed discrete masses of tonofilaments. These masses appeared to be engulfed by cells containing structures morphologically similar to premelanosomes, melanosomes and melanin granules of the elongated and rounded types. Degenerating mast cells may also contribute to the formation of eosinophilic masses, but these may be distinguished from the previous type by the presence of metachromatic granules.
Presence of leukocytes wuthin the gingival crevices during developing gingivities in dogs
Authors: Attström Rolf , Egelberg Jan
Published: June 2006

The presence of leukocytes in the cellular exudates within the gingival crevices during developing gingivitis has been studied in dogs. Repeated sampling was performed over a period of 35 days. An increase in the amount of leukocytes within the crevices was observed. The relative proportions of the various leukocytes in the crevicular exudates remained unaltered throughout the experimental period, showing 95–98% neutrophils, 1.2% lymphocytes and 1.3% monocytes. Experiments on cellular emigration, utilizing the skin window technique, indicated that a sustained predominance of neutrophils in an exudate may occur when dental plaque is continuously present on the surface of the lesion.
Remodelling of periodontal ligament in erupting molars of mature rats
Authors: Melcher A. H. , Correia M. A.
Published: June 2006

A wound was made 2 mm apical to the alveolar bone crest in the left mandible of 6 rats. The wound extended from the mesial of the first molar to the distal of the third molar, and penetrated alveolar process, periodonlal ligament and into the roots of the teeth. The opposing maxillary molars were extracted, and the mandibular molars were allowed to erupt for 2. 4 or 5 days. Histological sections cut in the coronal plane through the wounds showed that the teeth had erupted, particularly after the longer time periods. It was evident that fibres of the periodontal ligament attached to cementum had been carried into the apical part of the wound. No fibres were found attached to the alveolar bone immediately coronal to the wound. Few organized bundles were seen to be attached to alveolar bone elsewhere in the ligament of erupting teeth. These results were interpreted as not lending support to the view that remodelling of the periodontal ligament in a mature tooth of limited eruption occurs in an “intermediate plexus”. Rather, they are thought to suggest that remodelling in a mature tooth in which eruption has been reactivated occurs predominantly in the peripheral part of the ligament.
An assignment of the inter‐ and intra‐ examiner agreement in scoring gingivities clinically
Authors: Alexander A. G. , Leon A. R. , Ribbons J. W. , Morganstein S. I.
Published: June 2006

Three inexperienced examiners received progressively intensive training in the use of the PMA and Gingival Indices. Each examiner achieved intra‐examiner reliability with each index after only a short period of instruction. No consistent pattern of inter‐examiner agreement was evident until the examiners had received extensive training which included clinical instructions by an examiner with a good knowledge of the indices. A high degree of correlation was found between the PMA and GI scores for an individual which suggested that the two different methods of assessing ‘so‐called’ severity produce similar results.

It was concluded that the Gingival Index system had the advantage that clear mandatory instructions had been laid down for its use. All reports of studies using either index should contain information on the intra‐ and inter‐examiner reliability achieved.
Ioden‐125 apparature for measuring changes in X‐ray transmission and the thickness of alveolar process
Authors: Henrikson Carl O. , Julin Per
Published: June 2006

A method has recently been described for the quantitative measurement of the mineral content of alveolar bonein vivowith the help of an iodine‐125 apparatus (Bergström and Henrikson 1970). A device for the intraoral positioning of the narrow‐beam radiation source is fixed to a silver cap splint made for each patient. The transmission of the X‐rays from the radioisotope l25I through the alveolar septum is measured by a scintillation crystal, Nal (Tl), and a pulse height analyzer.

As small changes in the mineral content were often concealed by fluctuations in the thickness of the alveolar process, e.g. postoperative swelling, an apparatus for the simultaneous measuring of changes in X‐ray transmission and the thickness of the alveolar process has been constructed. The radiation is collimated by tubular diaphragms and filtered by a thin tin layer. The tubes are used as electrical contact indicators while measuring the thickness of the jaw.

The alveolar septum consists mainly of hydroxy apatite, water, protein and fat. An estimation of the mass attenuation coefficients of the components shows that it is possible to approximate the components to hydroxy apatite and “organic matter”. It is shown that it is possible to determine the amount of hydroxy apatite in the region studied.
Ankylosis of teeth following thermal injury
Authors: Atrizadeh F. , Kennedy J. , Zander H.
Published: June 2006

Thermal injury to the periodontium via the root canal was produced in 12 squirrel monkeys in order to study the sequence of events leading to ankylosis. Three days and one week following such injury an area of necrosis was found in the periodontal ligament which was circumferential, involved both periodontal ligament and alveolar hone, extended approximately l/3 the length of the root and did not involve the epithelial attachment. Two and 3 weeks following thermal injury new fibroblasts and blood vessels were seen at the periphery of neerotic areas and progressively decreased the area of necrosis. This was accompanied by frontal resorption of bone and cementum. Rear resorption took place adjacent to areas where the periodontal ligament was still neerotic. By one month, healing had progressed so that neerotic tissue was no longer present, bone apposition was more prominant than resorption and in some areas tooth and bone had fused. Ankylosis persisted but a continuous remodeling process was taking place as evidenced by further resorption and bone formation until the end of the study (6 months).
Acid mucopolysaccharides in gingivities and periodontitis
Authors: Ciancio Sebastian G. , Mather Makyanne L.
Published: June 2006

Human Gingival Tissues was clinically classified as normal or periodontally involved. Acid mucopolysaccharides were extracted from this tissue. The measurable acid mucopolysaccharides extracted were chondroitin sulfules A and C. Concentration of chondroitin sulfate was lower in the tissue classified as periodontally involved when compared to the normal tissue.
Effect of experimental leukopenia on chronic gingival inflammation in dogs
Authors: Attström Rolf , Egelberg Jan
Published: June 2006

The effect of experimental leukopenia induced by nitrogen mustard on chronic gingival inflammation has been studied in dogs. The effect on the gingivae was assessed by measurements of crevicular leukocytes, gingival fluid and the level of acid phosphatasc activity in samples from gingival crevices. During leukopenia a reduction in all these parameters was observed. The values returned to normal in the post‐leukopenic period. The results obtained indicate that crevicular leukocytes may contribute to the enzyme milieu in the gingival crevice and that these cells, through their lysosomal enzymes, may influence the tendency of the dento‐gingival vessels to show increased permeability.
A METHOD FOR QUANTITATIVE ESTIMATION OF TISSUE COMPONENTS AND NUMBER OF MAST CELLS IN THE GINGIVA.
Authors: Angelopoulos A. P.
Published: June 2006

A new, systematic and precise method, used for the quantiative estimation of the principal tissue components (epithelial, connective tissue, vascular and inflammatory) of the gingiva and the number of mast cells per unit area of gingival tissue is described in detail. About 500 gingival sections were studied and more thatn 30,000 mast cells were counted with this method.

The material consisted of gingival biopsy specimens removed from 137 patients with either clinically normal or infamed and hyperplastic gingiva.

The biopsy technique and the processing of the gingival tissues are described. The sections were stained with Hematoxylin and Eosin, Toluidine Blue, Astrablau and Periodic Acid‐Schiff's method.

The instruments used in this study, the micrometer component quantitator and an alternative, the light microscope tissue quantitator are also described. Examples of the results obtained are presented and other considerations related to this method are discussed.
Host tissue response in chronic periodontal disease
Authors: Page R. C. , Simpson D. M. , Ammons W. F. , Schectman L. R.
Published: June 2006

Manifestations of inflammatory periodontal disease in a. colony‐maintained marmoset were studied. The disease was characterized clinically by an acute inflammatory response including redness, edema, exudation and spontaneous hemorrhage. Histopathologically, the cellular response observed was comprised of neutrophils and mononuclear cells, some of which could be definitively identified as macrophages. The lymphocyte‐plasma cell infiltrate which comprises a major feature of the disease in man was not a prominent feature in the marmoset. Indeed, only insignificant numbers of these cells were found even with electron microscopy. Thus, the host tissue response in the marmoset appears to differ significantly from that seen in man, and reservations must be exercised in the use of the marmoset as a model of the human form of the disease. The observation that the important clinical and histopathologic manifestations of chronic periodontal disease can occur in this animal without the presence of an extensive lymphocyte‐plasma cell infiltrate suggest that, contrary to current concepts, the activity of these cells at the local site may not be essential to the induction and progress of periodontal disease.
Ultrastructural localization of antibody to an antigen applied topically to rabbit gingiva
Authors: McDougall W. A.
Published: June 2006

After four weeks of repeated irrigations of intact labial gingival sulci of rabbit mandibular incisors with horseradish peroxidase (HRPO), antiperoxidase antibody was demonstrated ultra‐structurally in the cistemae of the endoplasmic reticulum of some plasma cells in the gingival lamina propria. Antibody was found also in all cell types of the plasmacytic series in the regional lymph nodes. It was present in the basement membrane and the adjacent connective tissue and in the extraneous cell coat material of crevicular epithelial cells. Continued topical irrigations eventually caused an allergic type inflammatory response which, if allowed to resolve, would reappear fifteen minutes after irrigating the gingival sulci with HRPO.
The vascular arrangement beneath the sulcular and junctional epithelium in different degrees of cellular infiltration of dog gingiva
Authors: Kindlová M. , Trnková H.
Published: June 2006

The capillary arrangement under the crevicular and attachment epithelium was observed in relation to the degree of inflammatory cell infiltration in clinically healthy marginal periodontium in dogs. Both factors were investigated in adjacent tissue segments. The vascular bed was studied on corrosive specimens and the infiltration On histologic specimens stained by haematoxylin and eosin. There was to some extent a relation between the pattern of crevicular vessels and the degree of inflammatory cell infiltrate. Variability of the vascular bed was found, which was not related to the degree of infiltration. The anatomy of the vascular bed did not depend on the particular tooth, surface, arch or animal studied.
Evaluation of a training programme for the PMA and the Gingival Index
Authors: Alexander A. G. , Leon A. R. , Ribbons J. W. , Morganstetn S. I.
Published: June 2006

Three examiners who had achieved inter‐examiner agreement using the PMA and Gingival Index parted for four months. After this period of time without contact only two examiners were still comparable when using each index. A training programme for use with each index was drawn up and used by each examiner to train a selected pupil. Two examiners were able to train their pupils so that there was inter‐examiner agreement between pupil and instructor. The third pair were un‐able to achieve consistent agreement with either index. It was concluded that the training programme was a useful means of instructing suitable individuals m the use of the PMA and the Gingival Index, but certain individuals may be incompatible.
Effect of filament diameter and density in toothbrushes
Authors: Robertson N. A. E. , Wade A. Bryan
Published: June 2006

The relative effectiveness on plaque removal and gingival health of three brushes containing 6: 10 nylon filaments of varying filament diameter and tuft density was evaluated in an un‐supervised double‐blind, cross‐over trial conducted on twenty subjects. The two brushes with filaments of 0.28 mm diameter were greatly superior to the brush containing filaments of 0.14 mm diameter. Although the brush of fine diameter filaments contained twice and thrice as many filaments as the others this did not compensate for the narrower filament. Differences between the two brushes with the broader filaments were not significant and increasing the number of tuffs by 40 per cent did not confer any benefits. Many of the brushes with the finer filaments showed considerable wear after two weeks use and there was almost universal condemnation of these by the subjects taking part in the trial.
Experimental gingivitis in the monkey
Authors: Listgarten M. A. , Ellegaard B.
Published: June 2006

Rhesus monkeys receiving an oral hygiene program which included brushing, interdental cleansing and topical applications of chlorhexidine gluconate demonstrated a clinically normal gingiva for periods of up to 3 months. Wide fluctuations within individual dental units were noted with respect to histological sulcus depth, degree of connective tissue infiltration with lymphocytes and plasma cells, and total leukocyte or polymorphonuclear leukocyte (PMN) counts in the Junctional epithelium, even when the plaque and gingivitis index scores were 0. Of 18 clinically normal dental units sampled, only 6 appeared free of connective tissue inflammation. However, more than half of the tissue blocks obtained from dental units with a gingivitis and plaque index of 0 also showed scores of 0 with respect to the connective tissue inflammation (CTI) score and the number of PMNs in the Junctional epithelium. Within three days following discontinuation of oral hygiene procedures, rhesus monkeys developed a clinically noticeable gingivitis which began in the interdental papillae. Increases in CTI scores and number of leukocytes in the Junctional epithelium were evident after 2 days without oral hygiene. These values tended to increase further during the experimental period. A slight, but significant increase in sulcus depth was also noted during this time period. Regardless of the clinical state of the gingiva, a positive correlation was established between CTI scores and the number of PMNs and leukocytes in the Junctional epithelium. In early gingivitis, the plasma cells did not appear to outnumber lymphocytes, as has been reported for chronic gingivitis of longer duration.
Fructoaldolase activity in non‐inflamed attached gingiva of rhesus monkeys
Authors: Bergquist J. J. , Nuki K.
Published: June 2006

Ultramicrochemical methods were used to assay fructoaldolase activity under optimum substrate mixture concentrations in clinically non‐inflamed attached gingival tissue of Rhesus monkeys. Precautions were taken to assure the clinical non‐inflamed status of the gingivectomy specimens. Frozen dried sections were dissected under a stereomicroscope into representative morphologically distinct fragments which ranged in weight from 14 to 240 nanograms (10−9 grams). Optimum assay conditions for the microassay of freeze dried fragments were determined in fresh gingival homo‐genates. Quantitative results for the various strata of epithelium, connective tissue and whole epithelium were calculated. The mean fructoaldolase activity was reported in micromoles of converted substrate per gram of dry tissue weight per minute at 37°C: surface layer 4·04, granular layer 15·57, spinous layer 23·58, basal layer 28·10, connective tissue 12·99 and whole epithelium 26·75. These results are higher than fructoaldolase activity reported in the literature for other epithelial tissue, such as skin of the parietal region of the scalp and the plantar surface of the foot. However, the results of the present investigation are compatible with the activity assayed for mucous membrane of the lip, a tissue less commonly involved in chronic inflammatory processes than is the gingival tissue assayed in this study.
The nature of the granules within sulcular epithelial cells
Authors: Innes P. B.
Published: June 2006

An ultrastructural, cytochemical, autoradiographic and radioisotopic uptake study has been made of the sulcular epithelium in an attempt to explain the function of the prominent Golgi apparatus and the associated membrane bound granules which are found in the cytoplasm of the sulcular epithelial cells. Some of the granules appear to be lysosomal in nature in that they are acid phosphatase positive and in some instances they appear to release their hydrolytic enzymes into the intercellular space. The evidence presented suggests that many of the remainder of the granules are related to the production of materials which become incorporated into the extraneous cell surface coat of the epithelial cells. The radioisotope experiments suggest that the rate of synthesis of cell coat material is higher in the sulcular epithelium than it is in the oral epithelium
The quantitative analysis of Sb, Ag, Zn, Co and Fe in human dental calculus by neutron activation analysis and high‐resolution gamma spectrometry
Authors: Retief D. H. , Cleaton‐Jones P. E. , Turkstra J. , Smit H. J.
Published: June 2006

The sample to be analysed, and a standard of known composition, were irradiated simultaneously in the poolside facility of a nuclear reactor for 130 hours in a thermal neutron flux of approximately 2×1013 n.cm−2. sec−1, and the induced radioactivity compared after a cooling period of four weeks. The investigation was done with a high resolution Ge(Li) detector coupled to a fully transistorized 4000 channel analyser. The concentration of five elements, namely Sb, Ag, Zn, Co and Fe, was determined in human dental calculus by instrumental activation analysis and found to be 0,68 ppm, 0,18 ppm, 174 ppm, 0,08 ppm and 54 ppm respectively.
Uptake of chlorhexidine to hydroxyapatite
Authors: Emilson C. G. , Ericson Th. , Heyden G. , Magnusson B. C.
Published: June 2006

The uptake of chlorhexidine to hydroxyapatite was studied in vitro. Data were obtained indicating a multilayer adsorption at high concentration (>0.02 %) and a stable monolayer at lower concentrations. The clinical significance of such a monolayer in plaque prevention is discussed. Adorption of chlorhexidine did not affect the acid solubility of hydroxyapatite.
Some effects of chlorhexidine on the plaque flora of the Beagle dog
Authors: Hamp S.–E. , Emilson C. G.
Published: June 2006

Three series of experiments were performed during which Beagle dogs were given a plaque forming diet, in Series I 10 dogs were sprayed twice daily with 0.2 per cent chlorhexidine and 10 controls with saline for six months. In Series II the same treatment was used for 18 months in 16 dogs (8 treated. 8 controls). In Series III, comprising three dogs, the teeth of the left jaws, were subjected to two different concentrations of chlorhexidine for 5 + 5 weeks (2 resp. 0.1 %) while the teeth of the right jaws received saline treatment. During a subsequent period of 3 months all teeth were created with saline.

Dental plaque was sampled at the end of the three experimental periods, in Series III also one, three, six and thirteen weeks later. The sensitivity to chlorhexidine of the plaque bacteria was tested using a modification of “the paper disc method”. In all series the plaque bacteria from chlorhexidine treated teeth displayed reduced sensitivity to the drug. After termination of the chlorhexidine treatment in the Series III‐experiments the reduced sensivity to chlorhexidine of plaque bacteria from chlorhexidine treated teeth slowly approached the corresponding values from saline treated teeth.

Plaque samples taken after 18 months (Series II) were studied by means of a dilution‐plate method. The‐ dominating colonies from each plate were identified as gram‐negative aerobic rods. Most of the bacteria from chlorhexidine treated dogs grew on trypticase soy agar plates containing 320 μg/ml chlorhexidine. while bacteria from the saline treated animals only grew on plates containing 20 μg/ml.
Autoradiographic studies of 14C‐chlorhexidine given orally in mice
Authors: Magnusson B. , Heyden G.
Published: June 2006

The distribution of 14C‐chlorhexidine diacetate and digluconate applied to the back of the mouth in young female mice was studied with apposition autoradiography and liquid emulsion micro‐autoradiography. The uptake after single or repeated doses was observed in animals allowed to survive from 15 minutes to 2 months.

The radiolabelled chlorhexidine showed a marked, affinity to the epithelial lining of the alimentary and respiratory tracts. It also appeared in the liver and kidneys. In animals sacrificed 2 weeks after treatment the bulk of the material had left the body. However, even 2 months after a single dose traces could be demonstrated in the respiratory tract, in the secretory mucosa of the stomach and in the kidneys.

Chlorhexidine is metabolized and excreted via the same pathways as most foreign compounds. A generalised use of chlorhexidine in the prophylaxis of dental diseases must abide the results of adequate toxicological data.
The mode of action of chlorhexidine
Authors: Davies A.
Published: June 2006

Radioactive chlorhexidine * (14C labeled in the phenyl rings) was used to study absorption by and desorption From Streptococcus mulans and teeth.

When S. mutans was grown in brain heart infusion broth, the rate of absorption by the bacteria was rapid, but when bacteria were grown in medium containing sucrose, absorption was slow apart from an initial rapid phase. Very slow absorption was observed by organisms grown on wire immersed in the sucrose medium. Thus there appears to have been some barrier delaying absorption when the culture medium contained sucrose.

Studies with human teeth showed considerable variation between teeth but the rates of absorption and desorption were generally slow.
Effect on dental plaque formation and some in vitro properties of 12 bis‐biguanides
Authors: Gjermo P. , Rølla G. , ÅRskaug L.
Published: June 2006

Six alkyl‐, 4 alicyclie‐ and 2 aryl‐bis‐biguanide formulations have been tested for plaque inhibition in vivo. The participants refrained from mechanical oral hygiene for 3 days while they employed aqueous lest solutions as mouthrinses twice daily. During the experimental period the plaque formation was enhanced with frequent sucrose rinses. The antibacterial activity, the toxicity in cell cultures and the affinity for proteins of the same compounds were also studied. All the test agents showed plaque inhibitory capacity, most of them on a level comparable to that of chlorhexidine. There was a trend towards correlation between antibacterial activity, toxicity in cell cultures, and plaque inhibition. The affinity of the compounds for bovine albumin seemed to be pH‐dependent, thus indicating an electrostatic affinity between the bis‐biguanides and protein. It has been suggested previously that protein‐drug interaction might be an important aspect of the mechanism of chlorhexidine retention in the mouth. Discoloration of teeth and silicate fillings were frequently observed.
Activation of latent collagenase by microbial plaque
Authors: Robertson Paul B. , Cobb Charles M. , Taylor Robert E. , Fullmer Harold M.
Published: June 2006

Sterile extracts of whole human microbial plaque released substantial latent collagenolytic activity in gingival collagenase preparations, homogenates of polymorphonuclear leukocytes, and tissue macrophages. The plaque activation factor was thermolabile, nondialyzable, and had essentially no inherent collagenolytic activity.
The fine structure of human connective tissue mast cells in periodontal disease
Authors: Barnett M. L.
Published: June 2006

Electron microscopic examination of the walls of periodontal pockets revealed that connective tissue mast cells were distributed throughout the tissue. These cells had a variety of shapes, and were often in close association with remaining collagen fibers, as well as with smaller fibrils and other collagen fragments. Totally distrupted, necrotic mast cells were also observed which had morphologically intact granules in continuity with the extracellular space.
Trauma and progression of marginal periodontitis in squirrel monkeys
Authors: Polson A. M.
Published: June 2006

In continuation of a series of investigations designed to evaluate co‐destructive factors in periodontal disease, a single severe mechanical injury was produced subjacent to marginal periodontitis by wedging a toothpick between second and third bicuspids in squirrel monkeys. Marginal periodontitis alone was induced on the contralateral side for the same period of time for comparison of the progression of periodontitis with and without the subjacent traumatic lesion. Statistical analysis of the measurements from the cemento‐enamel junction to the most apical cell of the junctional epithelium and to the most coronal point of alveolar bone forming the wall of the periodontal ligament showed that the progression of periodontitis was not affected by the presence or absence of the mechanical injury.
Effect of periodontal dressings on fibroblasts in vitro
Authors: Hildebrand Carole N. , De Renzis Frank A.
Published: June 2006

This study was designed to evaluate the effect of four commercially available dressings (Coe, PPC‐Eugcnol, PPC‐Non Eugenol, and Ward's Wondr Pak) on a monolayer of cells, employing the cell culture assay plate assembly. Monolayers of L929 fibroblasts were grown out on the cell culture assay plates and stained with a vital stain, .01 % Neutral Red, 8 mm discs of prepared periodontal dressings, as well as sterile filter paper and high density polyethylene discs, which served as controls, were placed on the monolayer. Observations were made at 1, 2, 6, 8 and 24 hour intervals, and measurements of the toxic zones were recorded. Results indicate that all periodontal dressings tested in this system demonstrated definite cytotoxicity. Both macroscopically and microscopically, the first signs of cell damage and/or death were observed adjacent to Ward's Wondr Pak and PPC‐Non Eugenol dressings. Although these two dressings produced the earliest toxic signs, after 24 hours Coe‐Pak produced the most extensive zones of destruction, while PPC‐Eugenol appeared to be the least toxic.
Periodontal conditions in patients treated with dental bridges
Authors: Silness John , Ohm Elisabeth
Published: June 2006

The periodontal condition of 162 splinted approximal abutment tooth surfaces was compared with that of 162 contralateral tooth surfaces which were not fastened together. The Plaque Index (Silness & Löe 1964), the Gingival Index (Löe & Silness 1963), and the Margin Index (Silness 1970a) were recorded. Pocket depths were measured as explained by Glavind and Löe (1967). In bridge recipients who had received periodontal treatment and instruction to improve oral hygiene and who had no subgingival retainer margins in the embrasure areas between the splinted teeth, the periodontal condition was no better or worse than that of the contralateral area with which it was compared. Bridge recipients who had not been systematically influenced to change the tooth cleansing habits and who had subgingival retainer margins in the embrasure area between the splinted teeth, showed a considerable deterioration of the periodontal condition as compared to that of the contralateral area.
Biochemical aspects of calculus formation
Authors: Mandel Irwin D.
Published: June 2006

In an effort to identify factors responsible for individual variations in the amount and rate of salivary calculus formation, submaxillary and parotid secretions were examined from twenty heavy and twenty light calculus formers. The samples were assayed for total calcium, magnesium and phosphorus and for lysozyme and acid phosphatase activity. Individual and pooled submaxillary and parotid samples from five heavy and five light calculus formers were compared by polyacrylamide disc electrophoresis, immunoelectrophoresis, immunodiffusion and adsorption on hydroxyapatite. Reciprocal adsorption was also carried out on antisera to the submaxillary saliva from the two clinical groups. The mean calcium concentration of submaxillary saliva was significantly higher in heavy calculus formers than light formers. In the group of heavy formers, 75% of the values were above 10 mg%; in light formers, 20%. There were no significant differences in submaxillary magnesium and phosphorus or parotid calcium and phosphorus. Lysozyme activity, but not acid phosphatase was significantly lower in heavy formers, suggesting that alteration of bacterial cell walls can affect calculus formation. The electrophoretic and immunochemical studies strongly suggest that there are no proteins present in saliva of heavy calculus formers that are absent in light formers. There were, however, differences in quantities of the various salivary proteins in different individuals. Although no quantitative differences characteristic of heavy or light calculus formers as a group could be discerned, variation was sufficient to warrant further quantitative study.
Clinical and histologic characteristics of normal gingiva in dogs
Authors: Attström R. , Graf‐de Beer M. , Schroeder H. E.
Published: June 2006

The aims of the present study were to establish normal gingiva in dogs, to characterize the clinical conditions prevailing and to stereologically describe the structural composition of the normal gingival tissues. Three beagle dogs were subjected to regular oral hygiene procedures during 15 weeks. Measurements of gingival fluid flow and the amounts of crevicular leukocytes served to clinically assess the gingival conditions. Semi‐and ultrathin sections from biopsies of normal buccal gingival tissues from premolars were subjected to stereologic analysis based on morphometric point counting procedures. Gingival normality was achieved in two of the dogs. The normal gingival tissue in these dogs was characterized clinically by abscense of gingival fluid flow and by a minute amount of crevicular leukocytes. A gingival sulcus was most often absent. The junctional epithelium was without rete pegs, and the entire gingival connective tissue was densely filled by homogeneous collagen fiber bundles. A few isolated inflammatory cells were present in the junctional epithelium and the adjacent connective tissue. No clusters of inflammatory cells forming an infiltrate could be observed.

Stereologically, the gingival tissue comprised 48% epithelium and 52% connective tissue. The junctional epithelium occupied 10% of the gingival tissue and included a fraction of 2.8% occupied by leukocytes. The latter by volume comprised 50% neutrophilic granulocytes and mononuclear cells each. The connective tissue was composed of 67% collagen fibers, 14% free cells and 19% residual tissue. The composition of the connective tissue adjacent to the junctional epithelium differed somewhat from that of more central connective tissue fractions.