bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of fluoride pretreatment and ascorbic acid on bone growth in tissue culture
Authors: Golub L. , Chow K.
Published: July 2006

The addition of ascorbic acid to tissue culture media was found to increase the collagen and mineral content of bones grown in vitro both effects resulting apparently from an increased rate of collagen synthesis. Ascorbic acid also increased the solubility of the bone collagen, possibly by increasing the accumulation of newly synthesized, soluble, collagen in the bone at a rate faster than the formation of crosslinkages between the collagen molecules. Pretreating bone in vitro with fluoride increased the weight of cultured bone primarily by increasing the mineral content. The effect was greatest in the presence of a low rate of collagen synthesis. When collagen synthesis was accelerated by ascorbic acid, fluoride pretreatment caused a lesser increase in bone mass and actually depressed collagen synthesis. It would appear, therefore, that the effect of fluoride pretreatment on bone growth is dependent in part on the rate of collagen synthesis by bone cells. Fluoride pretreatrnent decreased the solubility of the collagen matrix of bone indicating an affect on intermolecular crosslinking. The increased degree of crosslinking due to the fluoride pretreatment may account, in part, for the inhibition of bone resorption in tissue culture.
A vital microscopy morphology of study of normal the and inflamed gingiva
Authors: Hock Janet , Nuki Klaus
Published: June 2006

Using a specially constructed microscope and transilluminating the intact free gingiva of ferrets, opossums, cats, dogs and rhesus monkeys, blood flow and vascular morphology were observed. Recordings were made on motion picture film at speeds up to 300 frames per second. The state of health of the gingiva was assessed clinically, histologically and by vital microscopy and the three assessments compared.

The results indicate that free gingiva which have never been involved in inflammation exhibit a vascular morphology which can be described as a network. With the onset of histopathologic inflammatory changes, the network transforms to a characteristic loop appearance. Five stages of morphologic change are described, based upon the vascular topography seen at various stages of the cellular inflam‐ matory response.

It is concluded that the vascular changes of inflammation in the free gingiva of the species studied, precede clinical and epithelial changes.
Periodontal changes in the rat induced by a fat‐free diet
Authors: Prout R. E. S. , Tring F. C.
Published: June 2006

The effect of feeding normal rat cake, high sugar fat supplemented and high sugar fat‐free diets on the periodontal tissues of rats has been studied. It was found that feeding a fat‐free diet resulted in periodontal changes. The effect is considered to he due to the systemic effect or essential fatty acid deficiency with an associated contribution from impaction in the gingival crevice due to the physical consistency of the fat‐free diet.
Effect of experimental leukopenia on chronic gingival inflammation in dogs
Authors: Attström Rolf , Tynelius‐Bratthall Gunilla , Egelberg Jan
Published: June 2006

Leukopenia was induced in six beagle dogs with chronic gingivitis by the injection of heterologous anti‐neutrophil scrum. During leukopenia, the number of neutrophils in the gingival crevice and within the gingival tissues was reduced. Concomitant with the reduction of neutrophils, the amount of gingival fluid decreased. The activity of acid phosphatase, hyaluronidase and protease in crevicular samples was determined and was found to decrease in parallel with the reduction in neutrophil number. All parameters returned to normal during the post‐leukopenic period. The results of the present study support previous suggestions that neutrophils at the dento‐gingival junction contribute to the enzyme milieu in the gingival crevice and that these cells, through their lysosomal enzymes, may induce vascular damage in periodontitis.
The interdental gingivae
Authors: McHugh W. D.
Published: July 2006

Material from 20 young rhesus monkeys was prepared for study of the interdental gingival epithelium. An additional four young monkeys were injected with tritiated thymidine and radioautographs prepared for analysis of cell turnover.

It was found that the interdental gingiva between recently erupted teeth in proximal contact has a col form. The appearance of the col can be simulated by vertical sections close to the roots of single teeth. Analysis of sections through the actual col showed that it is always lined by squamous epithelium, five or more cell‐layers thick, without any recognizable ameloblasts. The radioautographs showed consistent evidence of thymidine uptake, indicating cell‐division, in all epithelia lining the col. It was concluded that the histological features and turnover‐rate of epithelium in the interdental region are closely analogous to those of epithelium on other aspects of the teeth.

Clinical studies of the presence and amount of plaque and gingivitis in 1,075 intact interdental areas in 48 young adults showed a high degree of correlation between the presence and amount of plaque and the presence and severity of gingivitis, and lend support to the hypothesis that gingivitis starts interdentally because plaque accumulates there.
Transport across stratified nonkeratinized epithelium
Authors: Tolo Kåre
Published: July 2006

The external mucin layer, the cell membranes, the tight junctions, the intercellular substance and the basal lamina contribute to the compartmentalization of nonkeratinized stratified epithelium. Transport across an epithelial membrane can be conceived as a stepwise process involving different mechanisms for the transfer of solutes from one compartment to another. The inward transport route in gingival crevicular epithelium is considered to have a limited capacity as compared to the flow of tissue fluid into the crevice. The total transport across the crevicular epithelium is influenced by several factors and is probably not a linear function of the concentration of the solutions exposed to this membrane.
The ultrastructure of clinically normal sulcular tissues in the beagle dog
Authors: Garant P. R. , Mulvihill J. E.
Published: July 2006

The ultrastructure of clinically normal beagle sulcular epithelium and underlying connective tissue has been studied in order to obtain base line information for comparison with similar studies of overtly inflamed gingiva. Normal sulcular epithelium in the beagle was observed to undergo a cytodifferentiation from typical keralinocytes of the stratum basale and stratum spinosum to flattened superficial cells which contained a relatively prominent endoplasmic reticulum and Golgi system. These cells also contained many dense granules of an unknown function. Narrow intercellular spaces filled with a material of moderate electron density were observed between flattened superficial cells. Moderate numbers of neutrophils were found in the epithelium along with “clear cells” of an unknown type.

The underlying connective tissue was characterized by a preponderance of well organized collagen libers and numerous fibroblasts. No unusual findings were noted in either blood vessels or peripheral nerves. Macrophages were prominently located in the lamina propria and in perivascular locations. Lymphocytes, neutrophils and plasma cells were seen in moderate numbers, usually located in the lamina propria portion of the sulcular wall. These cells when present in moderate numbers do not appreciably alter the integrity of the tissues and should be considered as components of a normal defense system.
Concentration and synthesis of acid glycosaminoglycans in gingiva of normal and orchidectomized rats injected with testosterone
Authors: Kofoed Jorge A.
Published: July 2006

Normal and orchidectomized rats were injected on alternate days with 10 mg of testosterone propionate for 20 days in order to study the effect of the hormone on both the distribution and the rate of synthesis of glycosaminoglycans in gingiva. Testosterone exerts a very specific effect on the acidic GAG by increasing the hyaluronic acid concentration about twice. The sulfated fractions do nor appear to be affected. The above increase is probably due to an augmentation of synthesis of hyaluronate. as evidended by an increased uptake of C14‐acetate by this fraction.
Conservation of tissue specifically after heterotopic transplantation of gingiva and alveolar mucosa
Authors: Karring T. , öStergaard E. , Löe H.
Published: July 2006

In eight monkeys separate tissue flaps of the buccal gingiva and alveolar mucosa adjacent to premolar teeth were transposed. In addition, free palatal grafts were transplanted to the anterior maxillary and mandihular alveolar mucosa. The grafting and the sacrifice of the animals were timed to yield observation periods of 5 and 14 days, 1–8, 10 and 12 months. Serial sections were obtained from the grafted and control tissues. After 2 months the grafted tissues displayed clinical features which were identical to those of the respective donor tissues. This appearance did not change throughout the experimental period. Tissue characteristics such as the distribution of collugenous, elastic and silver‐stained fibers, the absence or presence of a keratin layer and localization of PAS‐positive material in the epithelium were maintained. The tissue specificities of the gingival, alveolar and palatal mucosa were conserved after heterotopic transplantation. Thus, the clinical and structural features of these tissues are genetically rather than functionally determined. It is suggested that grafting of keratinized tissues is a better method for predetermining the postsurgical width of gingiva than the methods of mucogingival surgery ordinarily used.
A study of the elimination of chlorhexidine from tthe oral cavity using a new spactrophotometric method
Authors: Jensen Jørn Erik , Christensen Flemming
Published: July 2006

A method for the determination of chlorhexidine in saliva is described. The mean recovery rates observed with chlorhexidine digluconate added to saliva in the ranges 5–25,μg/ml and 25–200 μg/ml where 103.6 % and 102.8 % respectively. The lower limit of the method is in the vicinity of 5 μg of chlorhexidine digluconate. The accuracy was found to be ± 3 % and ± 1 % when the concentration of the samples were in the ranges 5–25 μg/ml and 25–200 μg/ml respectively. The method is not specific for chlorhexidine and the amount of interfering material in saliva was found to be equivalent to 3.45 ± 0.54 μg/ml of chlorhexidine digluconate. The rate of elimination of chlorhexidine digluconate from the mouth after one mouthrinse with 20 mg followed approximately the equation describing a process of the first order. The mean values of the half‐times (t/2) and the initial concentrations (Cmax) was found to be 63 ± 11 min and 153 + 27 μg/ml respectively. The concentration of chlorhexidine digluconate was higher than the proposed minimal inhibitory concentration for oral streptococci of 5 μg/ml for approximately 5 hours. The significance of this in relation to the clinical effect of mouthrinsing with chlorhexidine is discussed. The amount of chlorhexidine digluconate swallowed after one mouthrinse was estimated to be approximately 4 mg corresponding to 20 % of the dose.
Freeze‐etching and dental research
Authors: Newman H. N.
Published: July 2006

Dental plaque is the aetiologie factor common to caries and chronic periodontitis. Understanding of the structure of this microbial film has been hindered by the fact that conventional methods of fixation and embedding are more or less disruptive in their effects. Freeze‐etching provides a means of examining plaque at an ultrastructural level in a state more closely approximating to that existing in vivo than is possible with other methods. The technique has been applied to the study of several oral commensal bacteria. Nocardia, Bacillus subtilis and Streptococcus viridans species have been shown to possess particulate cytoplasmic membranes, more particles being present on outer than on inner aspects. The previously described pattern of the spore coat of B. subtilis is confirmed, and, as in other non‐oral species, the organisms examined appeared to possess regularly structured cell walls. The banded appearance of S. viridans is similar to that in S. mutans recently seen using scanning electron microscopy.

Similar features of cell wall and cytoplasmic membrane have been observed in samples of dental plaque. Specimens resembling outer (salivary) surface plaque as prepared for conventional electron microscopy were found to contain numerous types of organism, principally coccal, in a fairly homogeneous matrix. Many cells possessed intracytoplasmic organelles. In the deeper layers, extracellular bodies were sometimes visible in the interbacterial matrix. Several types of fibrillar component were observed, passing between adjacent bacterial membrane layers, extending from the cell wall into the plaque matrix and connecting adjoining organisms. It is suggested that such fibrillar structures may be as significant in maintaining attachment of micro‐organisms to one another and to the tooth surface as any inherent stickiness of polysaccharides. Some organisms were found to be joined to one another by broad, structureless junctional zones. Many organisms possessed intracytoplasmic inclusions and cells were frequently septate.
The effect of estrogen progesterone and cortisol on gingival inflammation
Authors: Deasy M. J. , Grota L. J. , Kennedy J. E.
Published: July 2006

Two methods were used to induce gingival inflammation in squirrel monkeys (8 ovariectomized females and 3 males) with known levels of progesterone, estrogen and cortisol. Plasma progesterone and cortisol were assayed by a competitive binding technique. A bioassay of vaginal epithelium was used to assess estrogen activity. The ovariectomized animals were divided into two equal groups. Group I was injected with 10 mg progesterone and 0.2 mg estrogen twice daily for 50 days, producing elevated levels of these hormones. The remaining females (Group II) and the males (Group III) received vehicle for the same length of time. Regardless of the manner by which it was induced, gingival inflammation, as assessed by histometrics, was most severe in ovariectomized animals with no detectable progesterone and minimal estrogen (Group II). Group II, also, had lower levels of cortisol than the ovariectomized animals receiving progesterone and estrogen (Group I) and the males (Group III).
Horizontal tooth mobility and the menstrual cycle
Authors: Friedman Lawrence A.
Published: July 2006

Horizontal tooth mobility was determined in 31 females during the course of one complete menstrual cycle. No significant changes in horizontal tooth mobility were observed concomitant with the menstrual cycle. Fourteen females reported the regular use of anovulatory drugs. No significant changes in horizontal tooth mobility were observed. Tooth mobility was significantly less among the anovulatory drug users.
Host tissue response in chronic periodontal disease
Authors: Ammons William F. , Schectman Larry R. , Page Roy C.
Published: July 2006

The normal periodontium and manifestations of gingival and periodontal disease were studied in 120 living marmosets (Saguinus oedipus) and in the skulls of 40 additional animals to determine the possible usefulness of the marmoset as a model for investigation of the host tissue response in chronic periodontal disease. The general clinical and anatomic features of the animal are very similar to those seen in man; however, most of the adult animals exhibit severe occlusal abrasion and evidence of occlusal traumatism. Although gingival inflammation was observed in almost all of the animals examined, only 18.2% of the total gingival units were affected and the severity was exceptionallly limited. The prevalence of bony lesions indicative of the presence of chronic inflammatory periodontal disease was 0.5% and all of the lesions observed were associated with open contacts or plunger cusps. Thus, the prevalence of spontaneous chronic progressive periodontal disease in wild‐trapped marmosetes appears to be very low.
Ultrastructure of the dento‐gingival junction after gingivectomy
Authors: Listgarten M.
Published: July 2006

The lateral incisors of 2 cynomolgus monkeys were removed with the adjacent gingiva in situ at intervals of 12 to 49 days after gingivectomy. Electron microscopic examination of the specimens indicated that epithelial reattachment may occur in 12 days or less under these experimental conditions. Hemidesmosomes and a basement lamina were regenerated against enamel as well as coronal and root cementum surfaces. Reattachment appeared to occur against both morphologically normal and superficially altered cementum. Enamel lamellae extending through the thin coronal cementum layer were not disturbed during the surgical procedure. Hemidesmosomes appeared to regenerate more rapidly than the basement laminas against either the tooth surface or the gingival connective tissue.
The fine structure of gingivitis in the Bengal
Authors: Garant P. R. , Mulvihill J. E.
Published: July 2006

The subepithelial connective tissues of chronically inflamed gingiva were infiltrated by numerous well developed plasma cells. These cells were usually grouped together forming islands of cells which exhibited similar degrees of cytoplasmic differentiation. Young plasma cells contained well developed Golgi areas and an abundant system of granular endoplasmic reticulum, in the form of parallel stacks of flattened cisternae. In more mature plasma cells the cisternae of the granular endoplasmic reticulum were usually dilated by an accumulation of granular material Occasional plasma cells contained extremely large elements of endoplasmic reticulum (Russell bodies) while others contained crystalloid deposits within the cistemae of the reticulum. The degeneration of plasma cells with a consequent release of their cytoplasmic contents was frequently observed. Such cells were usually located near the sulcular epithelium while most of the normal plasma cells were usually located within the deeper connective tissue. These observations suggest that the liberation of antibody in the region of the inflamed sulcular epithelium may proceed via the degeneration of mature plasma cells.
Electron microscopy of acid phosphatase in the exudate from inflamed gingivae
Authors: Frank R. M. , Cimasoni G.
Published: July 2006

An ultrastructural study on human gingival fluid made it possible to localize acid phosphatase in polymorphonuclear leucocytes, bacteria and to a lesser degree in histiocytes. The polymorphonuclear leucocytes with autophagic bodies, and the histocytes contained intact and ruptured lysosomes as well as phagocytic vacuoles with engulfed bacteria. The surface of leucocyte cell membranes sometimes presented a positive enzymatic reaction. Large bodies, rich in acid phosphatase were observed in mast cells. In the epithelial cells scattered fine lead precipitates were noted and the epithelial nuclei sometimes reacted positively. In Gram positive bacteria, acid phosphatase was localized between the cytoplasmic membrane and the cell wall, whereas in Gram negative bacteria a positive reaction was observed in the outer layers of the cell wall. Bacteria without cell walls were surrounded by a lead precipitate. In addition, lead stainings were located in the bacterial cytoplasm. The major acid phosphatase activity seemed to be related to the leucocytes and the micro‐organisms.
Polar and neutral lipids of epithelium and connective tissue of pig gingiva
Authors: Rabinowitz J. L. , Tavares C. , Marsh J. B.
Published: July 2006

Pig gingiva was separated by collagenase treatment into epithelium and connective tissue components. No difference in DNA content was noted, but the RNA was significantly decreased during the separation procedure, especially in connective tissue. The collagen content of the connective tissue component was twice as high as that of epithelium. The neutral lipid and phospholipid content of each component was determined, and the phospholipid content of epithelium was found to be significantly higher. Significant differences between the layers were also found in triglycerides and cholesterol, which were higher in connective tissue. Most of the free fatty acids, previously found to be rather high in whole gingiva, were found in the epithelium. The fatty acid composition of each of the neutral lipids and phospholipids is reported.
Malic dehydrogenase in non‐inflamed attached gingiva of dogs
Authors: Bergquist J. J.
Published: July 2006

Ultramicrochemical methods were used to assay malic dehydrogenase (M.D.H.) activity in non‐ inflamed attached gingiva of dogs. Precautions were taken to assure the clinical and histological 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 12 to 240 manograms. Quantitative results for various strata of epithelium, connective tissue and whole epithelium were calculated. The mean M.D.H. activities in micromoles of substrate converted, per gram of dry tissue weight per minute at 37° C. were: surface layer, 29; granular layer, 222; spinous layer, 329; basal layer, 598; connective tissue, 71; and whole epithelium, 337. Differences in aerobic metabolism between the present findings in dogs and those reported for rat oral mucosa may in part be due to the type of keratinization in the two species. These differences in M.D.H. activity in dog and rat tissue are compatible with previosuly reported results of investigations of the oxygen consumption of these tissues.
The development of the mouse molar periodontium
Authors: Atkinson M. E.
Published: July 2006

The normal development of the tissues of attachment of mouse molar teeth was studied using standard histological techniques. Jaws were taken from mice on the day of birth and each subsequent day, up to and including thirty days after birth, and examined. At birth, the molar teeth were in the late shell stage of development and were enclosed in the dental sac. Subsequent growth of the crown was accompanied by minor changes in the dental sac and alveolar bone. The periodontal ligament began to develop when root formation began. Fibres were laid down in a superior‐oblique orientation which was maintained throughout the prefunctional and functional phases of eruption although changes which gave rise to the cervical fibre groups took place in the latter part of the prefunctional phase. Changes in the alveolar bone and cementum were observed as the tooth became functional. It was concluded that the periodontal ligament was preadapted to function and changes in other tissues of attachment, occurring as the teeth attained functional occlusion, were designed to strengthen the attachment of the fibres to bone and tooth.
Effect of contraceptive on the periodontal tissue of rats
Authors: Roth Genevieve D. , Lin Hsien S. , Liu Frank T. Y.
Published: June 2006

Two groups of adult female Hollzman rats, injected subcutaneously 5 times a week with low and high doses of norethynodrel plus mestranol for 91 days failed to gain weight at the same rate as the controls. In measuring both the mandibular and maxillary bone loss there was it trend showing the greatest amount of bone loss in the controls, moderate loss in the low dosage and the least loss in the high dosage. The differences of Total mandibular bone loss between the controls and rats treated with high dose of Enovid‐E® were statistically significant. However when the bone loss was measured as a percentage of total mandibular size the differences were not significant. A 2% silver nitrate staining method for delineating the cemento‐enamel junction was developed. Under the present experimental condition; the injection of Enovid‐E® compared to the controls did not demonstrate adverse effects on the gingiva or on alveolar bone.
The relative efficiencies of some periodontal partial recording selections
Authors: Downer Martin C.
Published: June 2006

One hundred 11–15 year old clinic patients were examined, and the presence or absence of unequivocal gingivitis and periodontal pocketing was recorded separately for each permanent tooth, From the full‐mouth data, each subject was also scored using combinations of teeth recommended for partial recording with the PMA, GI, and PDI index systems. Spearman's Rank Correlation Coefficient (rs) was selected, after inspection of the frequency distributions, to express the associations between the partial recording and full‐mouth scores. From the values of rs, the relative efficiency of each partial recording combination was computed, in terms of the number of subjects required to provide a statistical test of similar power to that provided by a full‐mouth examination of 100 subjects. The GI combination proved to be the most efficient. Values for rs of 0.899 for gingivitis and 0.846 for periodontitis were obtained between this combination and the full‐mouth scores. It was estimated that 124 and 139 subjects, respectively, would be required for gingivitis and periodontitis assessments, using the GI selection, compared with 100 for a full‐mouth examination. None of the combinations adequately identified all subjects with one or more affected units.
A histochemical study of arylaminopeptidases in hydantoin induced hyperplastic, healthy and inflamed human gingiva
Authors: Larmas L. A. , Mäkinen K. K. , Paunio K. U.
Published: July 2006

Arylaminopeptidase activity in hydantoin induced hyperplastic, inflamed and healthy human gingiva was studied using various N‐L‐aminoacyl‐2‐naphthylamines as substrates. The activity was seen to be located in the basal cell layer of the epithelium in the entire connective tissue, but it was strongest just below the epithelium in all tissues. High enzymic activity was also observed in the inflammatory cells as well as in the capillary walls of hydantoinhyperplastic and inflamed gingiva. Strong enzymic activity was obtained when N‐L‐alanyl‐, N‐L‐methionyl‐ and N‐L‐leacyl‐2‐naphthylamine were used as substrates. Moderate activity was observed with N‐L‐arginyl‐2‐naphthylamine and N‐Llysyl‐2‐naphthylamine in other tissues except in healthy gingiva where the enzymic activity was low or nil. To test the possible involvement of aminopeptidase B in the material the reactions were performed both in the presence and absence of 0.2 M sodium chloride, which specifically activates this enzyme. There was no observable enzymic activity in any slices when N‐L‐prolyl‐2‐naphthylamine was used as substrate.

The role of different arylaminopeptidases in connection with gingival hyperplasia caused by diphenylhydantoin and the evident absence of enzymes specific to N‐L‐prolyl‐2‐naphthylamine are discussed.
Studies of mast cells in the human gingiva
Authors: Angeloploulos A. P.
Published: July 2006

The morphology of mast cells was studied in specimens from clinically normal and inflamed gingiva of 15 patients and from the tongues of two albino rats.

Two types of mast cells were described, the typical and atypical. Only the typical mast cells were used to study size and shape of human gingival and rat tongue mast cells. Their shape varied considerably from spherical to ovoid and elongated. Only 7·6% of the mast cells in the human gingiva were found to be spherical, while about 70% had a lenghtlwidth ratio from 1·1 to 2·0. Their area also varied; about 80% of the gingival mast cells had an area from 20 to 100 μm2, with an average of 68·05 μm2

No difference was found in the shape of mast cells between human gingiva and rat tongue, although the mast cells of the rat tongue were larger in size than those of the human gingiva.
Tooth irregularity and the height of the alveolar process in skulls
Authors: Thompson G. W. , Beagrie G. S.
Published: July 2006

The interrelationships of a modified Tooth Cervical Height Index (Davies et al. 1969) and tooth irregularity were evaluated on the posterior teeth of 90 skulls. Two readings were made for tooth displacement, rotation, and the Tooth Cervical Height Index for each maxillary and mandibular first bicuspid, second bicuspid, and first molar. The average Tooth Cervical Height Indices of the 6 posterior teeth ranged from 3·34 mm. for the mandibular first bicuspid to 1·63 mm. for the maxillary second bicuspid. Within each skull a definite relationship existed between the bone heights of the various teeth, viz., where a high recording was made on any one tooth there was tendency for high scoring on the remaining teeth of that skull. Tooth irregularity did not appear to have any association with the alveolar bone height.
A comparative wound healing study following gingivectomy by electrosurgery and knives
Authors: Aremband D. , Wade A. Bryan
Published: July 2006

Using a split mouth technique and random selection of operative techniques, gingivectomy was performed from first premolar to first premolar by electrosurgery on one side and by periodontal knives on the other side on thirty occasions. By clinical, photographic, cytological and histological methods of evaluation plus crevicular fluid measurement, no differences in healing between the two surgical modalities over a three week period were demonstrated, Little post‐operative pain was experienced but where there was pain it did not differ in severity between the two surgical procedures.
Long term effect of chlorhexidine on developing gingivitis in the Beagle dog
Authors: Hamp Sven‐Erik , Lindhe Jan , Löe Harald
Published: July 2006

Twenty Beagle dogs, ten in an experimental group and ten controls, were given a soft plaque forming diet for 12 months. A .2 per cent aquous solution of chlorhexidine gluconate was applied twice daily to the teeth and gingivae of the experimental animals. The dogs of the control group were similarly treated with saline. Assessments of plaque, calculus and gingivitis were performed after 7, 14, 21, 28 days and 2, 4, 6, 8, 12 months. Gingival exudate was also measured.

During a period of six months topical application of .2 per cent chlorhexidine essentially prevented plaque, calculus and gingivitis development, while control dogs exhibited large amounts of dental deposits and marked clinical signs of chronic gingivitis. After six months, however, plaque and gingivitis appeared also in the chlorhexidine group. At the termination of the experiment. Gingival Index and exudate scores of the chlorhexidine group had reached approximately half the values of the saline group. No clinical side effects but the occurrence of stain on teeth was registered during the entire experiment.
The effect of ascorbic acid on the turnover of collagen in bone in tissue culture
Authors: Golub L. M.
Published: July 2006

Ascorbic acid is required for collagen synthesis but its role in other aspects of collagen metabolism is unclear. Neonatal mouse calvaria were incubated in tissue culture in the presence of 0·05 or 50·0 μg/ml ascorbic acid to determine the effect on bone collagen synthesis, crosslinking and degradation. H3‐proline was added to the culture media to label the collagen newly synthesized in vitro with H3‐hydroxyproline. Ascorbic acid increased the synthesis but descreased the degradation of the H3‐hydroxyproline‐labeled bone collagen. Ascorbate increased the specific activity (CPM H3‐hyp/μg hyp) of the insoluble collagen, with no effect on the: acid‐soluble collagen, indicating that the newly synthesized bone matrix was more highly crosslinked. On the other hand, the degradation of the preformed unlabeled collagen appeared to be increased. It was concluded that ascorbic acid increased bone collagen remodeling in vitro by favouring the the accumulation of newly synthesized bone collagen and the removal or degradation of the older preformed material.
Changes in hyaluronidases in human saliva during the menstrual cycle
Authors: Prout R. E. S. , Hopps R. M.
Published: July 2006

The levels of tissue and bacterial hyaluronidases in human whole mouth saliva samples have been measured during the menstrual cycle; the level of tissue hyaluronidase falling at menstruation and the level of bacterial hyaluronidase showing no significant change. The change in tissue hyaluronidase activity in the saliva is considered to be related to changes, in progesterone levels in the body during the menstrual cycle.
Consistency of plaque distribution in individuals without special home care instruction
Authors: Cumming Boyd R. , Löe Harald
Published: July 2006

The consistency of the individual patterns of plaque distribution was evaluated over a period of time. Fifteen, first semester dental students, who had not received special home care instructions. were evaluated on five alternate days according to the criteria of the Plaque Index system. The study has shown that the pattern of plaque distribution demonstrated by each of the individuals was unique. Also. while various regions of the dentition were sometimes free from plaque and sometimes covered by plaque other areas existed in the mouths, of all subjects which were consistent: either clean or covered by plaque. The clinical implications of these findings are discussed.
Localization of mucopolysaccharides in epithelial‐Iike cells cultured in vitro
Authors: Thonard J. C. , Wiebkin O. W.
Published: July 2006

Previous studies, demonstrating mucopolysaccharides (MPS) in tissue cultured epithelial cells did not eliminate the possibility that some of the reported staining could be attributed to acidic lipids, nucleic acids and substrate movement, although these possibilities were deemed minimal due to the employment of generally accepted techniques. Human amnion cells were grown on coverslips in tissue culture. Some coverslips were treated to remove MPS, lipid or nucleic acids before fixation and staining, whilst others were merely fixed and stained. Fixatives included 10 % formalin. 10 % formalin in 80 % ethanol, 1 % cetylpyridinium chloride and 1 % cetylpyridinium chloride in 80 % ethanol. Stains employed were the Hale colloidal iron, alcian blue, toluidine blue at pH 6.0 and 2.5 and sudan black. Substrate extractions were effected with testicular hyaluronidase, ribonuclease, KOH and pyridirje. The present, report confirms earlier results and provides evidence that human epithelial‐like cells produce MPS in vitro the staining specificity of which eliminates lipids and nucleic acids as the source of the observed reactions. It is claimed that the MPS is mainly confined to the cell surface and therefore is more discernible as a MPS stainable moiety in contiguous cell cultures than when cells are dispersed singly.
Evidence of alveolar bone loss in rats fed an atherogenic diet
Authors: Plenk H. , Rudas B. , Waechter R.
Published: July 2006

Normal Wistar rats, aged four and six month, were fed an atherogenic diet and the resulting periodontal changes were determined after six and eight weeks using histological, histochemical and histometrical methods. The changes of the alveolar bone remodelling adjacent to incisor teeth were compared with those around molar teeth.

A diminished formation of new bone and an increased osteoclastic resorption were found in the alveolar bone of the rats fed the atherogenic diet. In addition gingival inflammation and the development of periodontal pockets were observed.

Using histometrical evaluation it could be demonstrated that these alveolar bone changes were significantly more pronounced in the incisor teeth than in the molars. It is supposed that the latter finding is due to the more intense remodelling of the alveolar bone in the constantly growing teeth of rodents.
Changes in hyaluronidases in human saliva during the menstrual cycle
Authors: Prout R. E. S. , Hopps R. M.
Published: July 2006

The levels of tissue and bacterial hyaluronidases in human whole mouth saliva samples have been measured during the menstrual cycle; the level of tissue hyaluronidase falling at menstruation and the level of bacterial hyaluronidase showing no significant change. The change in tissue hyaluronidase activity in the saliva is considered to be related to changes in progesterone levels in the body during the menstrual cycle.
A comparative study of the surface of keratinized and non‐keratinized oral epithelia
Authors: Cleaton‐Jones P. , Fleisch L.
Published: July 2006

Portions of clinically healthy epithelium from the hard and soft palates, free and attached gingivae, cheek, floor of mouth and lip from the vervet monkey (Cercopithecus aethiops) were examined with the light and with the scanning electron microscope.

The epithelia can be subdivided histolocally into keratinized and non‐keratinized types. Each of these has a definite surface appearance irrespective of the region from which they are derived. Non‐keratinized epithelia show a corrugated surface formed by microplications while keratinized epithelia have a cratered or pitted appearance. In addition, the parakeratinized free gingival surface may be masked by the presence of pellicle. The reason for the different surface appearances is obscure but may be related to different intercellular interdigitations in the two types of epithelia.
The fine structure of human epithelial mast cells in periodontal disease
Authors: Barnett M. L.
Published: July 2006

Ultrastructural study of the lining of the pathologic pockets of patients with chronic periodontal disease revealed the presence of mast cells within the epithelial layer. These intraepithelial mast cells had a variety of unusual shapes, and frequently appeared dendritic. These cells also had cytologic features which suggested that they were actively synthesizing mast cell granules and releasing them into the extracellular space. The findings indicate that intraepithelial mast cells may play a role in the pathogenesis of the sulcular epithelial changes which are seen in human periodontal disease.
Human gingival lipids
Authors: Rabinowitz Joseph L. , Rutberg M. , Cohen D.W. , Marsh J. B.
Published: July 2006

Lipid analyses were performed on gingival biopsies obtained from 28 patients with periodontal disease. For each of the patients studied, biopsies were taken from areas with well‐defined periodontal pathology as well as from areas showing no obvious disease. The individual specimens were assayed for total lipids, neutral and phospholipids, collagen, non‐collagen protein, DNA and RNA. The phospholipids and the neutral lipids were further separated into their individual constituents, and the amount of each and its fatty acid composition was determined. The results were compared between the diseased and non‐diseased samples and with previous results with pig gingiva. No statistically significant differences were evident between diseased and non‐inflammed gingival areas. However, since all patients had been initially treated by scaling, root planing, and personal hygiene for weeks prior to Surgery. it is not possible to conclude that no changes in gingival lipids accompany periodontal disease. In comparison with pig gingival tissue, human tissue showed a higher DNA and non‐collagen protein content on a wet weight basis. All other parameters measured were about the same for the two species except that the sphingomyelin content of human gingiva was lower.
Alveolar bone loss and tooth attrition in skulls from different population samples
Authors: Lavelle C. L. B.
Published: July 2006

614 skulls were examined, comprising 49 australoids, 80 negroids, 66 mongoloids and 419 caucasoids. The degree of alveolar bone loss was significantly greater in negroids and australoids than caucasoids or mongoloids. Also the degree of alveolar bone loss decreased between Romano‐British and 19th. century times in caucasoids. A similar pattern of variation was noted in the degree of tooth attrition. The results from this study are not sufficient, however, to assess whether the variation between the various population samples reflect genetic or environmental factors.
Influence of temporomandibular joint receptors on tactile occlusal perception
Authors: Caffesse Raul G. , Carraro JuanJ. , Albano Enrique A.
Published: July 2006

Previous studies have shown that tactile occlusal perception is not eliminated when teeth are anesthetized. Based on the suggestion that such perception could be influenced by other receptors in the masticatory system, the possible role of the temporomandibular joint receptors was considered in this study.

The minimal thickness (in units of 8 microns) detected between opposing teeth initially and after anesthesia of both temporomandibular joint capsules, was determined in 15 subjects. Results showed a mean difference for the group of 2·0 units with a standard error of 0.54 which was highly significant (p < 0·001). However, 40% of the subjects did not show any variation after anesthesia.

It is concluded that receptors from the temporomandibular joint capsule may play an important role in determining the tactile occlusal perception.
Mouthbreathing and gingivitis
Authors: Jacobson Lars
Published: July 2006

Fifty‐five 6 to 12 year‐old adenoid children were compared with forty healthy children of the same age to establish a positive correlation between mouthbreathing and gingival inflammation existed. The test group was composed of children with a history of medical complications due to enlarged adenoids. Gingival Index and Plague Index were used and, in addition, adenoid size and breathing habits were registered in both groups. Mouthbreathers were found to have higher GI‐ scores than nosebreathers (p<0·01). The most significant differences between test and control groups were found in the maxillary anterior region (p<0·001). Decreasing in GI‐scores were found in the following order: maxillary posterior region (p<0·001), mandibular anterior region (p<0·01), and mandibular posterior region (p<0·05). No statistical differences in PII‐scores existed between the two grops in any region of the dentition. The mechanism behind the increased inflammatory reaction in the test group is discussed. Since higher GI‐scores in mouthbreathers wer more obvious in areas especially subjected to the passage of air during mouthbreathing, destructive effects from dehydration is suggested as the most probable explanation.
Effect of dental plaque extracts on mammalian cells in vitro
Authors: Levine M. , Adams R. L. P. , Cowley G. C.
Published: July 2006

It is now generally accepted that chronic periodontitis probably follows the accumulation of bacterial plaque on teeth surfaces. Some investigators have claimed to show that substances from plaque damage cells in vitro, but their results appear difficult to assess. The present investigation was a further attempt at examining the effect of substances in an aqueous plaque extract on mammalian cell cultures in vitro. In addition, this effect was compared with that caused by substances in saliva. Plaque was collected onto ice from patients requiring dental treatment. The plaque was pooled, and homogenised in carrier saline (Earle's saline from which NaH2PO4, NaHCO3, and glucose had been omitted). The mixture was homogenised at 4°C. centrifuged, and the supernatant fraction, the plaque extract (PE), sterilised by millipore filtration. Unstimulated whole saliva was centrifuged, and the supernatant fraction sterilised in the same way as the Pe # HeLa, L 929, and BHK 21 C 13 established cell cultures, and foetal human lung fibroblasts at 4th passage in cell culture, were grown in Eagle's medium with Earle's saline, calf serum to 10% v/v, and penicillin and streptomycin each to 100 units per ml. The PE was found to contain material which damaged HeLa cells, and prevented the growth of all 4 cell types. This material did not seem to detach any of these cells from the dish, and was 20 times more concentrated in plaque than in saliva. These results indicate that mammalian cell cultures can be used to detect toxic substances in aqueous plaque extracts. These substances may possibly irritate junctional epithelium at the base of the gingival sulcus or pocket in vivo.
A comparative study of in vitro 3H‐17B estradiol binding in gingiva, skeletal muscle and uterus of ovariectomized rabbits
Authors: Rubright W. C. , Terman S. A. , Yannone M. E.
Published: July 2006

The 3H‐17B‐estradiol binding capacity of gingiva was compared, by in vitromethods, to those of uterus and skeletal muscle of ovariectomized. New Zealand strain rabbits. The estrogen binding kinetics and partial characterization of the uterine macro‐molecular receptor substance are presented. Neither gingiva nor skeletal muscle bound significantly more 3H‐17B‐estradiol than the buffer blank. The gingiva of this species probably can not be considered an estrogen sensitive tissue.
Histologic and histometric study of bone resorption after tooth movement in rats
Authors: Otero R. López , Parodi R. J. , Ubios A. M. , Carranza F. A. , Cabrini R. L.
Published: July 2006

The effects of orthodontic movement on rat molars produced by a specially designed device have been studied by means of histological and histometric methods. Areas of resorption start to increase after 12 hours and reach a maximum after 48 hours. The number of osteoclasts starts to increase 20 hours after initiation of the orthodontic force attaining its maximum at the 60 hours period. This finding suggests that the initiation of bone resorption is not associated with an increase in the number of osteoclasts.
Electron microscopic evidence of a cellular attachment between junctional epithelium and dental calculus
Authors: Listgarten M. A. , Ellegaard B.
Published: July 2006

Following scaling, the gingiva of rhesus monkeys was maintained in a state of clinical normalcy by single daily intra‐oral swabs with 2 % chlorhexidine gluconate, supplemented by toothbrushing and interdental cleansing with toothpicks three times per week. Chance findings in 2 animals, one maintained for 3 months on this regimen, the other for only 3 weeks followed by a period of 12 days without oral hygiene, revealed that under these circumstances, the junctional epithelium is able to form an attachment to a calculus mass which contained morphologically recognizable bacterial cells. Electron microscopy revealed that this attachment was mediated through a dental cuticle, a basement lamina and hemidesmosomes. The ultrastructure of the epithelial attachment to calculus was indistinguishable from that which exists between junctional epithelium and various tooth surfaces. These results may be due to the inhibiting effect of chlorhexidine gluconate on plaque formation and possibly a concomitant lowering of the toxicity of calculus.
The effect of age on mitotic activity in rat oral epithelium
Authors: Karring T. , Löe Harald
Published: July 2006

One hundred and thirty eight male white albino rats were used in this study. Serial sections were prepared of the palate, tongue, gingiva and ear and were stained with hematoxylin and eosin. The experiment utilized one group of rats aged 3 months and another at 15 months. At 3 hour inter‐ vals during a 24 hour period 3 rats from each group received an injection of colehicine and were sacrificed 3½ hours later. Counts of arrested metaphases demonstrated that the mitotic activity of young and old animals were dmilar or tended to decrease with age. In 2, 3, 6, 15 and 25 month old rats no relationship was found between the number of nucleated cells in the various epithelia and the age of the animals. Using colchicinized rats and non‐treated rats the duration of the mitotic phase was estimated in tongue epithelium of young and old animals. The result of this ex‐periment indicated that the duration of the process of cell division tends to increase with age. The results of this study favour the opinion that mitotic activity decreases with increasing age.