Mucins MUC5B and MUC7 in minor salivary gland secretion of children and adults.

OBJECTIVE: The study was designed to investigate the relative amount of MUC5B and MUC7 in minor salivary glands in children and adults, in order to test the hypothesis that secretion of salivary mucins changes between childhood and adulthood. METHODS: Ninety individuals in the age-groups 3-year-olds, 14-year-olds, and young adults 20-25 year-olds were recruited. Sialopapers were applied on the labial and the buccal mucosa and then placed in the Periotron 8,000 (Proflow ) for calculation of the amount of saliva. The assessment of MUC5B and MUC7 was carried out in an ELISA using the LUM5B-2 and the LUM7-1 antiserum, respectively. RESULTS: MUC5B and MUC7 were detected in the labial minor gland saliva in all age groups. In buccal gland saliva, only a few individuals in each age group showed detectable amounts of the mucins. In the labial area, a significantly lower level of MUC7 was noted in 3-year-olds compared with adults. CONCLUSION: The results indicate a site-dependent difference in minor gland mucin secretion and an age-related difference in the labial gland secretion of MUC7.

Main sensory neuropeptides, but not VIP and NPY, are involved in bone remodeling during orthodontic tooth movement in the rat.

During orthodontic tooth movement (OTM) a remodeling of the periodontal ligament (PDL) and the alveolar bone occurs. We have recently observed that the expression of CGRP and substance P (SP) increases in the PDL and dental pulp in response to buccally directed OTM of the upper first molar in the rat. We have now examined whether there is also an involvement of VIP and NPY in this type of OTM. A sectional arch wire cemented to the upper incisors exerted an orthodontic force, mediated by a coil on the lingual side of the tooth, for 24 hours. It was observed that the blood vessels in the periodontal ligament were supplied with VIP- and NPY-immunoreactive (IR) nerve fibers, whereas VIP-IR nerve fibers in contrast to NPY-IR fibers were only occasionally observed in the dental pulp. No significant changes were observed in response to OTM. The observations suggest that VIP and NPY, in contrast to the main sensory neuropeptides CGRP and SP, are not involved in the tissue processes that occur in the remodeling of PDL and alveolar bone during orthodontic tooth movement.

Margin adaptation of dispersion and traditional amalgams with reference to plasticity: a clinical comparison.

Margin adaptation of dental amalgam restorations made from traditional vs. dispersion-type alloy was compared by clinical evaluation with the reference to plasticity of the mix at insertion. Also, variations in sealing properties were assessed for precondensed and not-precondensed amalgam mixes of both alloys. The data presented confirm the clinical superiority of amalgam made from dispersed type alloy. A higher plasticity tended to result in less margin deterioration for amalgams of the traditional type alloy. In vitro leakage with the dispersion type amalgam far exceeded that of the traditional amalgam.

Mast cell heterogeneity in various oral mucosal sites in the rat.

Two distinct types of mast cells are recognized in the rat: connective tissue mast cells (CTMCs), found in the peritoneal cavity, skin, tongue, etc. and mucosal mast cells (MMCs), found in the intestinal mucosa. The two subsets differ functionally and can be defined by histochemical methods. The aim here was to characterize the mast cell population in various oral mucosal sites. Biopsies were taken from the tongue, buccal mucosa, gingival mucosa and intestine (jejunum) of 20 rats. For optimal preservation of the MMCs, a fixative with low aldehyde concentration and low pH was used. The biopsies were embedded in paraffin. The first of three consecutive sections (5 microns) was stained with toluidine blue for 30 s, the second with toluidine blue for 7 days and the third with astra blue/safranine. Cells positive with toluidine blue after 30 s were classified as CTMCs, and those positive after 7 days but not after 30 s as MMCs. Cells positive to safranine in the astra blue/safranine staining sequence were classified as CTMCs and those positive to astra blue as MMCs. The total number of mast cells was similar in the superficial layers of all oral tissues studied. There were more mast cells in the deeper than in the superficial portions of the tongue. Mast cells with staining characteristics and size similar to those observed in the intestinal mucosa (MMCs) were found together with 'classical' connective tissue mast cells (CTMCs). The results suggest that the mast cell population of oral mucosal tissues of the rat contains both CTMC- and MMC-like cells.

Localization of plasminogen activators and plasminogen-activator inhibitors in human gingival tissues demonstrated by immunohistochemistry and in situ hybridization.

The plasminogen-activating system plays an important part in tissue proteolysis in physiological as well as pathological processes. Plasminogen activators u-PA (urokinase) and t-PA (tissue) as well as the inhibitors PAI-1 and PAI-2 are present in gingival crevicular fluid in concentrations significantly greater than in plasma. This fact, and the finding that the concentrations of t-PA and PAI-2 are higher in areas with gingival inflammation, indicate local production of these components. The present study describes, by means of in situ hybridization and immunohistochemistry, the localization of the plasminogen activators and their inhibitors in gingival tissues from patients undergoing periodontal surgery. t-PA mRNA and t-PA antigen were primarily found in the epithelial tissues, predominantly in the sulcular and junctional regions, although occasionally in the oral epithelium and in blood vessels of the connective tissue. u-PA and u-PA-receptor signals were seen in single cells within the junctional and sulcular epithelia and adjacent to blood vessels close to the junctional epithelium, but rarely in the oral epithelium. Similar to t-PA, the predominant location of PAI-2 mRNA was the gingival epithelia. In the junctional and sulcular epithelia, PAI-2 mRNA was seen throughout the thickness, while in the oral epithelium the strongest signals were seen in stratum granulosum and stratum spinosum. PAI-1 mRNA was invariably found in the connective tissue associated with blood vessels. The present study confirms earlier indications of local production of plasminogen activators and their inhibitors in gingival tissues. In addition, the results demonstrate that t-PA and PAI-2 in these patients are produced predominantly in the epithelial tissues. Furthermore, the presence of t-PA and PAI-2 seems to be most pronounced in the areas likely to be subjected to bacterial assault.

Increasing expression of tissue plasminogen activator and plasminogen activator inhibitor type 2 in dog gingival tissues with progressive inflammation.

Urokinase and tissue-type plasminogen activators (u--PA and t--PA) are serine proteases that convert plasminogen into plasmin, which degrades matrix proteins and activates metalloproteinases. The PAs are balanced by specific inhibitors (PAI--1 and PAI--2). Local production of t--PA and PAI--2 was recently demonstrated in human gingival tissues. The aim now was to investigate the production and localization of t--PA and PAI--2 in gingival tissues from dogs in three well-defined periodontal conditions; clinically healthy gingiva, chronic gingivitis and an initial stage of ligature-induced loss of attachment. At the start of the experiment the gingiva showed clear signs of inflammation. Clinically healthy gingiva were obtained after 21 days period of intense oral hygiene. Attachment loss was induced by placing rubber ligatures around the neck of some teeth. Biopsies were taken from areas representing the different conditions and prepared for in situ hybridization and immunohistochemistry. In clinically healthy gingiva both t--PA mRNA and antigen were expressed in a thin outer layer of the sulcular and junctional epithelia. No t--PA signals or staining were seen in connective tissue. Both mRNA signaling and immunostaining for t--PA were stronger in chronic gingivitis. In areas with loss of attachment, t--PA mRNA as well as antigen were found in the sulcular and junctional epithelia to a similar degree as in gingivitis. Occasionally the connective tissue was involved, especially in connection with vessels. PAI--2 mRNA was seen in a thin outer layer of the sulcular and junctional epithelia in clinically healthy gingiva, but no signals were seen in connective tissue. PAI--2 antigen was found primarily in the outer layer of the sulcular and junctional epithelia. Some cells in the connective tissue were stained. In gingivitis, PAI--2 signals were mainly found in the same locations, but more intense and extending towards the connective tissue. Immunostaining was seen in the outer half of the sulcular and junctional epithelia as well as in the upper part of the connective tissue, close to the sulcular epithelium. In sites with loss of attachment, PAI--2 mRNA was found throughout the sulcular and junctional epithelia, as was the antigen, which stained intensely. No PAI--2 mRNA was seen in connective tissue; the antigen was found scattered, especially near vessels. This study shows that the expression of both t--PA and PAI--2 increases with experimental gingival inflammation in the dog, and furthermore, the two techniques demonstrate a strong correlation between the topographical distribution of the site of protein synthesis and the tissue location of the antigens for both t--PA and PAI--2. The distribution correlates well with previous findings in humans.

Partial recording of gingivitis and dental plaque in children of different ages and in young adults.

In epidemiologic studies, total recordings of the amount of dental plaque and the degree of gingival inflammation tend to be too time-consuming. Various partial recording methods have accordingly been suggested. However, the validity of these methods when applied to different age groups has not been investigated sufficiently. The aim of the present study was to test whether different systems for partial recording of plaque and gingivitis can take the place of a full-mouth recording in children of different ages and in young adults. Ninety children, divided into three age groups (4-6, 7-9, 14-16 yr), and 30 adults (20-22 yr) were examined. The degree of gingival inflammation was recorded using the Gingival Index and the amount of dental plaque using the Plaque Index. Two partial recording methods were tested. One of these covered the teeth suggested by Ramfjord, modified for children with a primary dentition, and the other the front segment of the maxilla. The results were compared with those from an examination of all tooth surfaces. In all age groups excellent agreement was found between the partial recording method suggested by Ramfjord and a full-mouth recording of both the gingival state and the amount of dental plaque. Examination of the maxillary front segment was less accurate and resulted in a systematic underestimate.

Intraindividual effect of daily supervised flossing on caries in schoolchildren.

The aim was to study the effect of flossing on proximal caries in children grouped according to different combinations of dietary and oral hygiene habits. 140 12--13-year-old children flossed the right or the left lateral region of the mouth once every school-day for 2 years by pulling a waxed floss once up and down through the proximal contacts. Proximal caries was recorded on bitewing films, taken at the baseline and at the 2-year registration. Diet history was obtained four times during the period. Oral hygiene was classified according to the number of bleeding points registered with a feather-loaded probe at the final examination. Caries increments on the control side during the experimental period were calculated for groups with the same habits. A logical border with respect to the amount of new caries was then established between suitable and unsuitable dietary habits as well as between sufficient and insufficient oral hygiene. No statistically significant difference was found between the control and experimental subgroups in the different combinations of dietary and oral hygiene habits, neither with respect to the whole material nor comparable contralateral surfaces. The numerical differences were so small that the technique of flossing studied here cannot be recommended.

Growth and development considerations in the diagnosis of gingivitis and periodontitis in children.

Increasing information emphasize the relevance of the prevention, early diagnosis and early treatment of periodontal diseases in children. In order to avoid erroneous diagnosis and unnecessary treatments, the pediatric dentist is required to differentiate between pathologic processes and normal changes that take place in the periodontum with age. The present review outlines structural and functional changes of the periodontal structures, the establishment and maturation of the oral microflora and immune defense reactions to periodontal pathogens in children and adolescents. The age-related tendency to develop gingivitis, that is evident in children and adolescents, may be related to changes in the bacterial composition of the dental plaque, the inflammatory cell response, hormonal changes, morphological differences, tooth eruption and shedding. The hormonal influence on the gingival tissues and the composition of the dental plaque are of particular relevance during puberty. Large ranges for the prevalence of attachment loss, periodontitis or destructive periodontal disease in children and adolescents have been reported. The variance in values may be related to population characteristics, method of examination or diagnostic criteria that may include measurements of attachment loss and distances from the cementoenamel junction to the alveolar bone crest, both of which may be either physiological or pathological. The pediatric dentist should be able to diagnose gingival inflammation, attachment loss or distances from the cementoenamel junction to the alveolar crest which are out of proportion to the child's age and the amount of dental plaque. These may be indicative of a high susceptibility to periodontal diseases or reflect systemic conditions that affect the periodontum.

Histologic characteristics of the gingiva associated with the primary and permanent teeth of children.

The severity of the gingival inflammatory response to dental plaque increases with age, and it has been suggested that this phenomenon may be related to histological characteristics of the gingiva. The objective of this study was to compare the histological characteristics of the gingival tissues of primary teeth with that of permanent teeth in children. Prior to extraction, children were subjected to a period of thorough oral hygiene. Histological sections prepared from gingival biopsies were examined using the light microscope. One biopsy from each of seven primary and seven permanent teeth of 14 children, whose mean ages were 11.0 +/- 0.9 and 12.9 +/- 0.9 years respectively, was obtained. All sections exhibited clear signs of inflammation. Apical migration of the junctional epithelium onto the root surface was associated only with the primary teeth. Compared with the permanent teeth, the primary teeth were associated with a thicker junctional epithelium (P < 0.05), higher numbers of leukocytes in the connective tissue adjacent to the apical end of the junctional epithelium (P < 0.05), and a higher density of collagen fibers in the suboral epithelial connective tissue (P < 0.01). No significant differences were noted in the width of the free gingiva, thickness of the oral epithelium, or its keratinized layer. In conclusion, this study indicates significant differences in the microanatomy of the gingival tissues between primary and permanent teeth in children.

Benzodiazepines in child dental care: a survey of its use among general practitioners and paediatric dentists in Sweden.

Dental treatment in children too young or too apprehensive to co-operate is often performed under sedation. The aim of this study was to survey the use of rectal and oral liquid and tablet benzodiazepine sedation in Swedish child dentistry, and estimation of treatment success. A questionnaire was sent to 500 randomly selected dentists (GPs) working in the Public Dental Health Service and all (77) specialists (PDs) working at paediatric dentistry clinics. Benzodiazepine sedation was used by 73% of the GPs and 97% of the PDs. Seven per cent of the GPs and 87% of the PDs had sedation sessions at least once a month. Of the GPs, 60% administered the sedation rectally, 7% orally in liquid form, and 39% orally in tablet form. For PDs, the corresponding figures were 97%, 78%, and 68%. Sixteen per cent of the GPs and 84% of the PDs used midazolam for rectal sedation. PDs rated rectal sedation better than the GPs (p < 0.001). GPs rated their experiences of rectal sedation as better the more frequent the use (p = 0.03), as did PDs concerning oral liquid sedation (p = 0.03). Thus, it seems that a more regular use of sedation is advantageous in achieving better treatment outcome.

Periodontal conditions in Vietnamese immigrant children in Sweden.

The aim of the present study was to compare the periodontal health in Vietnamese immigrant children in Sweden with that of native Swedish children. The study groups consisted of 42 6-17-year-old Vietnamese children and 42 age- and sex-matched Swedish children. Information on systemic health was obtained by interview. Clinical examination included recordings of dental plaque, supragingival calculus, bleeding on probing, probing depth, clinical attachment loss and caries. Radiographs were evaluated for presence of marginal bone loss, proximal calculus and proximal caries. In addition, previously obtained and filed radiographs were used as a supplement in order to evaluate if the children at any time point during the ages 4-11 years had experienced proximal calculus or bone loss in the primary dentition. The Vietnamese children showed significantly higher number of sites with bleeding on probing and with probing depths > or = 4 mm. Radiographic calculus was found in 55% of the Vietnamese and in 2% of the Swedish children. 5 Vietnamese children and 1 Swedish child showed periodontal bone loss at the time of examination. In all children except 1, the bone loss was confined to primary teeth. The retrospective analysis of available radiographs from the primary dentition showed that 28% of the Vietnamese children and 5% of the Swedish children had experienced bone loss in their primary teeth during the ages 4-11 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Periodontal health in adopted children of Asian origin living in Sweden.

In the present study the periodontal condition of a group of adopted 6-17 year-old children of Asian origin living in Sweden was compared with that of age- and sex matched Sweden children. Thirty-one Asian children and 31 Swedish children participated. Data on general health for all the children and on age at arrival for the Asian children was collected by interview. A clinical examination included recording of presence of plaque, supragingival calculus, bleeding on probing, probing depth, and caries. Radiographs were used to determine marginal bone loss (distance between the cemento-enamel junction and the marginal bone level > 2 mm), proximal calculus, and proximal caries. In addition, previously taken and filed radiographs of the primary dentition of the older children and current radiographs of the younger children with primary teeth were analysed to determine the prevalence of bone loss and calculus. The children of Asian origin showed a significantly higher number of surfaces with plaque and bleeding on probing. No significant differences were noted in the number of individuals with probing depths > or = 4 mm, supragingival calculus, or radiographic calculus. Three of the Asian and none of the Swedish children displayed radiographic bone loss. The retrospective analysis of all available radiographs from the primary dentition showed that 9 of 29 (31%) Asian children and 2 of 29 (7%) Swedish children had experienced bone loss in primary teeth.

Local inflammatory reactions in juvenile and adult rats.

The present investigation was designed for the study of the early phases of local inflammatory reactions in juvenile and adult rats. A recently developed experimental model, based on continuous diffusion of an inflammation inducing agent, was applied. Thirty-five juvenile (6 weeks) and thirty-five adult (6 months) rats were used. Two sterile teflon tables were implanted subcutaneously on the back of each animal on each side of the midline. After three weeks, when a connective tissue capsula had developed, the tablets were replaced by one test tablet (containing lipopolysaccharide) and one fresh teflon tablet, respectively. In each group five animals were sacrificed on day 0 and fifteen animals on each of day 7 and 21. Biopsies comprising tablet and surrounding tissue were taken and exposed to routine histological treatment. The total number of cells was assessed in four defined areas in connection with each tablet. Cells classified as leukocytes were recorded separately. The analysis was performed at 1000x magnification in a light microscope. During the first seven days an increase in the number of leukocytes was seen in the tissue adjacent to the test tablets in both young and adult rats. After 21 days the number of leukocytes was still high in the adult group while in the juvenile group the number of leukocytes returned to the base-line level.

A new experimental model for studies of local inflammatory reactions.

The aim of the present study was to develop and evaluate a method for studies of the early phase of the local inflammatory reaction, based on continuous diffusion of an inflammatory inducing agent. 25 rats were used. Four sterile teflon tablets were implanted subcutaneously in the back of each animal. After 3 weeks, when a connective tissue capsula had formed, the tablets were replaced by two test tablets, containing 35 micrograms lipopolysaccaride, one placebo and one teflon tablet. Five rats were sacrificed on day 0, 4, 7, 14, 21, respectively, and biopsies comprising tablet and surrounding tissue were harvested and exposed to routine histologic treatment. The number of leucocytes was assessed in four defined areas adjacent to each tablet. During the first seven days an increase in the number of leucocytes was seen in the tissues adjacent to test tablets. After 14 and 21 days the number of leucocytes was still high but lower as compared to day 7. In the tissues bordering the placebo and teflon tablets only few inflammatory cells were found. The results suggest that the tested method is suitable for studies of local inflammatory reactions during a 21 day period in experimental animals.

Salivary mutans streptococci in 6-year-old children from a multicultural suburban area after attending an oral health program.

AIM: To investigate the prevalence of salivary mutans streptococci (MS) in children from a low socioeconomic multicultural suburban area and to evaluate if a 3-year comprehensive oral health education (OHE) program, initiated at the age of two years, had an impact on the saliva levels. STUDY DESIGN: Prospective clinical trial. METHODS: The material consisted of two cohorts of 6-year-old children from a suburban area in southern Sweden. One cohort (n=804) had participated in a OHE program with a focus on tooth brushing with fluoride toothpaste and flouride tablets added to the regular preventive care provided by the Public Dental Service. The second cohort (n=217) consisted of reference children only attending for regular dental care. Both cohorts were dominated by children with Arabic background. Salivary MS were evaluated by a chair-side test and caries was scored through clinical examinations. STATISTICS: Analyses were performed with Chi square tests, Pearson correlation coefficients and odds ratio calculations. RESULTS: The prevalence of salivary MS was high in both cohorts with approximately 90% harbouring the bacteria. One third of the children exhibited high counts (>10(6) CFU/ml) and there were no statistically significant differences between the groups. A statistically significant positive relationship between the levels of MS colonisation and caries prevalence was found in both cohorts. CONCLUSIONS: A 3-year OHE program implemented at the age of two years did not affect the high levels of salivary MS displayed in 6-year-olds living in a multicultural high-caries area.

Factors influencing the susceptibility to gingivitis during childhood--a review.

A variety of biological changes take place during childhood which have an impact on the development of gingival inflammatory disease. This paper reviews the literature concerning changes in the susceptibility to gingivitis during childhood. It is concluded that during certain periods the risk of developing gingivitis is relatively low, while in others the gingival tissues are more susceptible and react to bacterial irritation with inflammation. Factors that may be responsible for these changes include differences in bacterial plaque composition, in immune defence systems and in morphology of the gingival tissues, and also factors related to tooth eruption and puberty.

Long Range Force between Pre-Replication Complexes (Pre-RC) in DNA Controls Replication and Cell Cycle Progression.

A nonstationary interaction, that controls DNA replication and the cell cycle, is derived from a manybody physics model in a chemically open T cell. The model predicts a long range force F'(ξ)=-(κ/2) ξ(1-ξ)(2-ξ) between the pre-replication complexes (pre-RCs) bound by DNA, ξ=ϕ/N being the relative displacement of preRCs, ϕ the number of pre-RCs, N the threshold for initiation, and κ the compressibility modulus in thelattice of pre-RCs which behaves like an elastically braced string. Initiation of DNA replication is induced by a switch of sign of F'(ξ), from attraction (-)and assembly in the G(1) phase (0 < ϕ < N), to repulsion (+) and partialdisassembly in the S phase (N < ϕ < 2N), with release of licensing factors from the pre-RCs, thus explaining prevention of re-replication. Replication is terminated by a switch of sign of F at ϕ = 2N, when all primed replicons are duplicated once, and F(0)=0 corresponds to a resting cell in absence of driving force at ϕ = 0. The switch of sign of force at ϕ = N also explains the dynamic instability in growing microtubules (MTs), as well as switch in the interleukin-2 (IL2) interaction with its receptor in late G(1), at the restriction point. Shape, slope and scale of the response curves derived agree well with experimental data from dividing T cells and polymerizing MTs, the variable length of which is due to anonlinear dependence of the growth amplitude on the initial concentrations of tubulin dimers and guanosine-tri-phosphate (GTP).