Distribution of fluoride across cementum, dentine and alveolar bone in rats.

This study was undertaken to determine the fluoride distribution in cementum and neighboring hard tissues of the rat after different levels of fluoride administration via the drinking water. Specimens of cementum with underlying dentine and adjacent bone were removed from the distal roots of the first lower molars. The fluoride distribution in each specimen was determined in samples removed sequentially using an abrasive microsampling technique. Fluoride concentrations were highest at or near the surface and decreased towards the interior of cementum, dentine and alveolar bone in both control and experimental groups. With increasing fluoride intake, concentrations increased throughout the tissue. The distribution patterns of fluoride in cementum of contralateral teeth from the same animal were similar. Fluoride concentrations in cementum were higher than those of dentine and alveolar bone.

A biochemical and immunohistochemical study of the proteoglycans of alveolar bone.

The purpose of this investigation was to study the proteoglycans in alveolar bone of three animal species. Alveolar bone was obtained from humans, pigs, and rabbits. Portions were fixed, sectioned, and stained with monoclonal antibodies against keratan sulfate and chondroitin sulfate. In other samples, biochemical analyses were performed. After removal of the organic matrix by 4 mol/L guanidinium HCl extraction in the presence of proteinase inhibitors, proteoglycans in the mineralized matrix were extracted with 4 mol/L guanidinium HCl/0.5 mol/L EDTA/proteinase inhibitors, and characterized on the basis of their glycosaminoglycan content (cellulose acetate membrane electrophoresis), charge (DEAE-Sephacel and hydroxylapatite chromatography), size (Sepharose CL-6B chromatography and agarose/polyacrylamide gel electrophoresis), and amino acid content. The results indicated that keratan sulfate could be detected immunohistochemically and biochemically in rabbit bone only. The predominant glycosaminoglycan in pig and human alveolar bone was chondroitin sulfate, although some hyaluronate, dermatan sulfate, and heparan sulfate were also detected. The proteoglycans were found to be slightly smaller than gingival proteoglycans, but similar to those in cementum, dentin, and other bones. In addition to intact proteoglycans, some free glycosaminoglycan chains were also extracted from the mineralized matrix. Amino acid analyses showed some subtle differences between alveolar bone proteoglycan and those of the soft tissues of the periodontium.

Glycosaminoglycans of human alveolar bone.

Bone proteoglycan was extracted and the glycosaminoglycan (GAG) components identified. Chondroitin-4-sulphate was the major GAG detected and represented 93.8% of the total GAG extracted. In addition, hyaluronic acid (1.3%), dermatan sulphate (3.1%) and heparan sulphate (1.8%) were identified as minor constituents.

The relationship of the periodontal status to fluoride levels of alveolar bone and tooth roots.

The periodontal status and fluoride levels of alveolar bone and tooth roots were compared for subjects from a high (2.5 ppm F) and a low (less than 0.05 ppm F) fluoride area. The plaque index, gingival index, probing depth and loss of attachment were measured to determine the periodontal status. The fluoride levels were determined by the use of the fluoride ion-selective electrode. Both communities had high plaque and gingival indices. However, the mean pocket probing depths in both communities were less than 2.5 mm. No statistically significant differences could be found in the periodontal status between the 2 areas. The fluoride levels in bone and root were higher for subjects from the high fluoride area. No statistically significant difference could be demonstrated between the fluoride levels in alveolar bone and tooth roots for each area. It was found that the fluoride levels in bone and roots increased with increasing age, but to a lesser degree for subjects from the low fluoride area.

The glycosaminoglycan constituents of alveolar and basal bone of the rabbit.

Proteoglycan was extracted from alveolar and basal bone of New Zealand White rabbits using a sequential extraction procedure. Proteoglycans not associated with the bone mineral represented 1% of the total organic matrix whereas proteoglycans associated with the mineral represented 20% of the alveolar organic matrix and 12% of the basal organic matrix. Chondroitin-4-sulphate and keratan sulphate were identified in both alveolar and basal bone following protease treatment of the proteoglycan extracts and enzymic digestion with chondroitinase AC, ABC and keratanase. Differences were observed in the percentage of each glycosaminoglycan (GAG) in the total organic matrix. In alveolar bone samples, keratan sulphate and chondroitin-4-sulphate is present in equal proportions. In basal bone chondroitin-4-sulphate represents approximately half the value found in alveolar bone and keratan sulphate about a quarter. The extracts were examined by gel filtration on Sepharose 4B under associative conditions. The 280 nm absorbance profiles of proteoglycan from alveolar and basal bone were essentially similar with three main peaks evident, including molecular weight material in excess of 2 X 10(6). The bulk of the bone GAG appeared in the medium molecular weight range with trace amounts in lower molecular weight fractions.

Immunocytochemical localization of gamma-carboxyglutamic acid-containing proteins (osteocalcin) in rat bone and dentin.

Gla-protein or osteocalcin is one of the most abundant noncollagenous matrix proteins found in bone and dentin. The present study describes, with high resolution, the intracellular and extracellular distribution of Gla-protein in alveolar bone and incisor dentin. Sections of tissues embedded in Lowicryl K4M were incubated with rabbit antibodies to rat dentin Gla-protein. The site of the specific antigen-antibody reaction was revealed by the protein A-gold complex. Labeling was detected over bone and dentin while fewer gold particles were present over prebone and predentin. Gold particles were also seen over the protein synthetic organelles (rough endoplasmic reticulum, Golgi apparatus) of osteoblasts and odontoblasts. These findings confirm, with improved resolution, previous light immunohistochemical studies, and offer the possibility to examine the secretory pathway of the protein.

Immunofluorescence localization of type I and type III collagen and fibronectin in mouse dental tissues in late development and during molar eruption.

Affinity-purified antibodies produced intense staining for type I collagen in alveolar bone matrix and predentine, and moderate staining in the dentine matrix, lamina propria, connective tissue invaginating into papillary layer of the enamel organ, dental sac and periodontal ligament. No staining occurred in oral epithelium, stellate reticulum, stratum intermedium, ameloblasts and odontoblasts. Fibronectin was distributed similarly except at the interface between the epithelial diaphragm and pre-odontoblasts where type I collagen was absent but fibronectin was present. In contrast, type III collagen showed strong staining in the periodontal ligament and lamina propria but no staining in bone matrix, predentine, dentine and at the interface between the epithelial diaphragm and pre-odontoblasts. The staining pattern for type III collagen was similar to that of type I and fibronectin in other tissues including endosteal reticular tissue, the connective tissue invaginating into papillary layer and the extracellular matrix of the pulp.

Immunohistochemical distribution of collagens types IV, V, and VI and of pro-collagens types I and III in human alveolar bone and dentine.

The aim of the present study was to characterize the composition of the organic matrix in alveolar jaw bone and dentine using antibodies against pro-collagens Types I and III and collagens Types IV, V, and VI. After demineralization of oral hard tissues in 0.2 N HCl, antigenicity was well preserved and the distribution of the pro-collagens and collagens could be demonstrated. Staining for pro-collagen Type I was prominent around osteoblasts and in pre-dentine, indicating active de novo synthesis of Type I pro-collagen. Pro-collagen Type I was ubiquitous but was less abundant in bone and dentine, whereas pro-collagen Type III was seen only in areas of bone remodeling, in peritubular spaces, and in pre-dentine. Type IV collagen was limited to the basement membranes of vessels in osteons and bone marrow. Type V collagen was detected neither in pre-dentine nor in bone. In contrast, Type VI collagen was found in dentine and bone, showing a faint but homogeneous staining which, similarly to pro-collagen Type III, was pronounced around osteoblasts and in pre-dentine, areas of active bone and dentine formation. This study showed that the organic matrix of dentine and bone contains Type VI as well as Type I collagen. Pro-collagen Type III (and to a lesser extent collagen Type VI) is transiently produced during new formation and remodeling of oral hard tissues, and disappears once the matrix calcifies. Type I pro-collagen qualifies as a general marker protein for increased osteoblastic activity. We conclude that immunostaining for the different collagen/pro-collagen types can be used to assess normal or abnormal stages of bone/dentine formation.

Plasminogen activators in alveolar bone in man.

Plasminogen activators in alveolar bone in man was studied in quenching experiments by a fibrin slide technique with addition of monospecific antibodies against tissue plasminogen activators (t-PA) and urokinase (u-PA). The plasminogen activator activity was quenched in the slides with anti-t-PA. No quenching was observed in the slides with anti-u-PA. This does not exclude the possibility that enzymatically inactive pre-urokinase is present.

Effects of biochemical validation of self-reported cigarette smoking on treatment success and on misreporting abstinence.

Many investigators have reported that cigarette smokers who are trying to quit often falsely report being abstinent at the end of treatment. Unfortunately, much of the previous research designed to investigate this problem has been flawed, making the results difficult to interpret. We attempted to avoid these flaws and to investigate the measurement of alveolar carbon monoxide (CO) levels to validate self-reported smoking rates at the end of treatment. Participants in behavioral cessation clinics were randomly assigned to one of three conditions that varied in timing of exposure to information regarding CO measurement: at the beginning of treatment (demonstration of CO measurement, discussion of smoking effects on CO levels, and notification that individual CO levels would be measured at the conclusion of the clinic), at the end of treatment (demonstration, discussion, and notification of CO measurement prior to self-reports of smoking levels), or at the end of treatment (demonstration and discussion of CO measurement subsequent to self-reports of smoking levels). CO levels of all participants were measured at the end of treatment after they reported their current smoking levels. Only 16% of self-reports of abstinence were not verified by CO measurement. Smokers who observed the CO demonstration at the beginning of treatment were significantly more likely than the other two groups to achieve abstinence at the end of treatment and significantly less likely to misreport abstinence. Clinical and research implications of these results are discussed.

Changes in collagen types during the healing of rabbit tooth extraction wounds.

Three alpha chains of type V collagen--alpha 1 (V), alpha 2 (V), and alpha 3 (V)--were initially demonstrated together with the expected collagen types I and III in the pepsin-soluble fraction of both normal mandibular bone and tooth extraction wound tissues of rabbits, as analyzed by sodium dodecyl sulfate-gel electrophoresis. The total collagen content of each extraction wound, as determined by the hydroxyproline assay, was observed to increase continuously from day 5 through day 17 and then leveled off or decreased. The ratio of type V to type I collagen was significantly higher in the initial stage of wound healing and decreased sharply down to the level of mandibular bone by day 5. The ratio of type III to type I collagen in the pepsin-soluble fraction increased and reached a maximum on day 5, whereas it was maximal on day 7 in the cyanogen bromide-soluble fraction, and thereafter decreased gradually in both fractions. The ratio for the pepsin-soluble fraction was, however, significantly higher than that for the cyanogen bromide-soluble fraction in the early stage of wound healing.

Activated lung lymphocytes in hypersensitivity pneumonitis.

T-lymphocyte activation was investigated in peripheral blood and bronchoalveolar lavage (BAL) of four patients with hypersensitivity pneumonitis. The study was performed by flow cytometry with the use of immunofluorescence labeling with monoclonal antibodies to lymphocyte differentiation or activation antigens. Simultaneous measurement of DNA and RNA content by acridine orange staining was used for cell-cycle analysis. The various cell types were identified by their light-scattering properties. T cell activation was demonstrated in the BAL of all patients by the presence of T cells (OKT3 positive) bearing class II histocompatibility antigen (HLA-DR) and activated T cell markers (MLR 1-3). Lymphocyte proliferation was evidenced in BAL but not in blood of patients by an increased percentage of cells in S + (G2 + M) phases. In addition, T-lymphocyte subsets analysis revealed no abnormalities in the blood and no major imbalance in the BAL despite a slightly increased OKT4/OKT8 ratio. The finding of T cell activation and lymphocyte proliferation in hypersensitivity pneumonitis alveolitis is consistent with the contribution of a local type IV immune reaction to the pathogenesis of this disease.

Marginal bone height in adolescents participating in different preventive dental care programs.

A radiographic evaluation was made of the marginal bone height in youth, subject to different preventive dental care regimens. A test group consisted of 14-15-year-olds who for 4 years had received preventive dental care based on oral hygiene education, professional tooth cleaning and topical fluorides and/or mouth rinsings every 3rd week. A comparison group had been given solely fluoride mouth rinsings every 2nd week with no particular emphasis on oral hygiene measures. The radiographic evaluation showed average differences between the investigated groups of less than 0.3 mm in the distance from the cementoenamel junction to the alveolar bone crest. In the mandibular premolar-molar region of the comparison group, the marginal bone height differed significantly from the corresponding region in the test group. No such differences in the maxillary regions were noted. The clinical relevance of the results is discussed.

The distribution of fibronectin in rat tooth and periodontal tissues: an immunofluorescence study using a monoclonal antibody.

The distribution of fibronectin (FN) in longitudinal, buccolingual sections of decalcified adult rat periodontium and teeth was studied by indirect immunofluorescence using a monoclonal antibody. FN was present in virtually all regions of the periodontium, including the gingiva, periodontal ligament, many blood vessel walls, alveolar bone, incisor and molar predentine and dentine, and molar acellular and cellular cementum. The cementum of the incisor, ameloblasts, stratum intermedium and stellate reticulum, and the connective tissue of the pulp and the surface of ondontoblasts facing the pulp in the incisor and molar were not labeled for FN. FN distribution was not always uniform either within a given connective tissue or between different connective tissues of the same organ.