The effect of daily intake of green coffee bean extract as compared to Agiolax® on the alveolar bone of albino rats.

BACKGROUND: Obesity is a worldwide medical problem in which excess body fat is accumulated in the body. The use of weight loss supplements such as green coffee bean extract and Agiolax has become a common trend among people who want to lose weight in a fast and non-tiring way. As a result of their effect on fluid excretion, both of these products may be expected to have a damaging effect on the alveolar bone. OBJECTIVES: The aim of the present study was to evaluate the histopathalogical effect of green coffee bean extract as compared to Agiolax on the alveolar bone of albino rats. MATERIAL AND METHODS: Twenty-seven adult male albino rats were randomly assigned to 3 groups. Nine received distilled water daily for 2 months by oral gavage (the control group); the other 2 groups received 1 mg/100 g body weight green coffee bean extract or Agiolax 8 mg/100 g body weight daily for 2 months by oral gavage (the GC and Ag groups, respectively). The alveolar bones were dissected and examined histologically, histomorphometrically and by western blotting. RESULTS: The bone area percentage and the calcium level in serum were significantly decreased in the GC and Ag groups, while the calcium level in urine was significantly increased in both the experimental groups as compared to the control group. On the other hand, RANKL expression was significantly increased only in the GC group, and the tissue calcium (Ca) level was significantly decreased only in the GC group as compared to the control group. CONCLUSIONS: Long-term oral administration of green coffee bean extract and Agiolax might lead to alveolar bone loss. A greater deleterious effect was caused by green coffee bean extract, as it caused more RANKL expression, significantly reduced Ca level in the tissue and consequently decreased the bone area percentage.

A novel chemically modified curcumin reduces inflammation-mediated connective tissue breakdown in a rat model of diabetes: periodontal and systemic effects.

BACKGROUND AND OBJECTIVE: Periodontal disease is the most common chronic inflammatory disease known to mankind (and the major cause of tooth loss in the adult population) and has also been linked to various systemic diseases, particularly diabetes mellitus. Based on the literature linking periodontal disease with diabetes in a "bidirectional manner", the objectives of the current study were to determine: (i) the effect of a model of periodontitis, complicated by diabetes, on mechanisms of tissue breakdown including bone loss; and (ii) the response of the combination of this local and systemic phenotype to a novel pleiotropic matrix metalloproteinase inhibitor, chemically modified curcumin (CMC) 2.24. MATERIAL AND METHODS: Diabetes was induced in adult male rats by intravenous injection of streptozotocin (nondiabetic rats served as controls), and Escherichia coli endotoxin (lipopolysaccharide) was repeatedly injected into the gingiva to induce periodontitis. CMC 2.24 was administered by oral gavage (30 mg/kg) daily; untreated diabetic rats received vehicle alone. After 3 wk of treatment, the rats were killed, and gingiva, jaws, tibia and skin were collected. The maxillary jaws and tibia were dissected and radiographed. The gingival tissues of each experimental group (n = 6 rats/group) were pooled, extracted, partially purified and, together with individual skin samples, analyzed for matrix metalloproteinase (MMP)-2 and MMP-9 by gelatin zymography; MMP-8 was analyzed in gingival and skin tissue extracts, and in serum, by western blotting. The levels of three bone-resorptive cytokines [interleukin (IL)-1ß, IL-6 and tumor necrosis factor-α], were measured in gingival tissue extracts and serum by ELISA. RESULTS: Systemic administration of CMC 2.24 to diabetic rats with endotoxin-induced periodontitis significantly inhibited alveolar bone loss and attenuated the severity of local and systemic inflammation. Moreover, this novel tri-ketonic phenylaminocarbonyl curcumin (CMC 2.24) appeared to reduce the pathologically excessive levels of inducible MMPs to near-normal levels, but appeared to have no significant effect on the constitutive MMPs required for physiologic connective tissue turnover. In addition to the beneficial effects on periodontal disease, induced both locally and systemically, CMC 2.24 also favorably affected extra-oral connective tissues, skin and skeletal bone. CONCLUSION: This study supports our hypothesis that CMC 2.24 is a potential therapeutic pleiotropic MMP inhibitor, with both intracellular and extracellular effects, which reduces local and systemic inflammation and prevents hyperglycemia- and bacteria-induced connective tissue destruction.

Zanthoxylum piperitum reversed alveolar bone loss of periodontitis via regulation of bone remodeling-related factors.

ETHNOPHARMACOLOGICAL RELEVANCE: Zanthoxylum piperitum (ZP) has been used to prevent toothache in East Asia. AIM OF STUDY: In this study, we investigated the effects of ZP on periodontitis along with alveolar bone loss. MATERIALS AND METHODS: Twenty-eight male Sprague-Dawley rats were assigned into 4 groups; non-ligated (NOR), ligated and treated vehicle (CTR), ligated and treated 1mg/mL ZP (ZP1), and ligated and treated 100mg/mL ZP (ZP100). Sterilized 3-0 nylon ligature was placed into the subgingival sulcus around the both sides of mandibular first molar. After topical application of 1 and 100mg/mL ZP for 2 weeks, mandibles was removed for histology. In addition, SaOS-2 osteoblast cells were treated 1, 10 and 100µg/mL ZP for 24h to analyze the expressions of alveolar bone-related markers. RESULTS: Several alveolar bone resorption pits, which indicate cementum demineralization were decreased by ZP treatment. Topical ZP treatment inhibited periodontitis-induced alveolar bone loss. In addition, there were significant reduction of osteoclastic activities following topical ZP treatment in periodontium. The expression of RANKL was decreased in SaOS-2 osteoblast cells by treating ZP, while that of OPG was increased. ZP treatment increased the expressions of Runx2 and Osterix in SaOS-2 cells. CONCLUSION: In summary, ZP treatment inhibited alveolar bone loss as well as maintained the integrity of periodontal structures via regulation of bone remodeling. ZP may be a therapeutic target for treating periodontitis.

Effect of interleukin-4 on orthodontic tooth movement and associated root resorption.

OBJECTIVES: Interleukin-4 (IL-4) is a recognized immunomodulatory cytokine that regulates bone homeostasis. However, the influence of IL-4 on orthodontic tooth movement (OTM) and subsequent root resorption is still unknown. Therefore, the purpose of this study was to investigate the effect of IL-4 on tooth movement and its associated root resorption in a mouse model. MATERIALS AND METHODS: The maxillary first molars of four male mice for each experimental group were subjected to mesial force by a nickel titanium coil spring for 12 days. Control mice were not given appliances and injections. Varying doses of IL-4 were injected locally, adjacent to the first molar. Two sets of experiments were designed. The first set was composed of three groups: the control, treatment with phosphate-buffered saline (PBS), or 1.5 µg/day of IL-4. The second set was composed of five groups: the control, treatment with 0 (PBS only), 0.015, 0.15, or 1.5 µg/day of IL-4. The distance of OTM was measured and tartrate-resistant acid phosphatase positive cells along the loaded alveolar bone and root surface were identified. The root resorption associated with OTM was evaluated by a scanning electron microscope. RESULTS: The amount of OTM and the number of osteoclasts were significantly decreased in the IL-4-treated mice. Moreover, IL-4 significantly suppressed force-induced odontoclasts and root resorption. CONCLUSION: IL-4 inhibits tooth movement and prevents root resorption in the mouse model. These results suggest that IL-4 could be used as a useful adjunct to regulate the extent of OTM and also to control root resorption.

Histological analysis of the periodontal ligament and alveolar bone during dental movement in diabetic rats subjected to low-level laser therapy.

OBJECTIVE: The purpose of this research was to evaluate the histological changes of the periodontal ligament and alveolar bone during dental movement in diabetic rats subjected to low level laser therapy (LLLT). METHODS: The movement of the upper molar was performed in 60 male Wistar rats divided into four groups (n=15): CTR (control), DBT (diabetic), CTR/LT (irradiated control) and DBT/LT (irradiated diabetic). Diabetes was induced with alloxan (150 mg/kg, i.p.). LLLT was applied with GaAlAs laser at 780 nm (35 J/cm(2)). After 7, 13 and 19 days, the periodontal ligament and alveolar bone were histologically analyzed. RESULTS: The mean of osteoblasts (p<0.01) and blood vessels (p<0.05) were significantly decreased in DBT compared with CTR at 7 days, whereas the mean of osteoclasts was lower at 7 (p<0.001) and 13 days (p<0.05). In DBT/LT, only the mean of osteoclasts was lower than in CTR (p<0.05) at 7 days, but no difference was observed at 13 and 19 days (p>0.05). The collagenization of the periodontal ligament was impaired in DBT, whereas DBT/LLT showed density/disposition of the collagen fibers similar to those observed in CTR. CONCLUSIONS: LLLT improved the periodontal ligament and alveolar bone remodeling activity in diabetic rats during dental movement.

Effects of Er-Zhi-Wan on microarchitecture and regulation of Wnt/ß-catenin signaling pathway in alveolar bone of ovariectomized rats.

Recent studies have shown that Er-Zhi-Wan (EZW), a traditional Chinese medicine consisting of Herba Ecliptae (HE) and Fructus Ligustri Lucidi (FLL), had a definite antiosteoporotic effect on osteoporotic femur, but its effect on osteoporosis of alveolar bone remains unknown. In the present study, we investigated the effects of Er-Zhi-Wan (EZW) on the microarchitecture and the regulation of Wnt/ß-catenin signaling pathway in the alveolar bone of ovariectomized rats. Thirty Sprague-Dawley rats were randomly divided into three groups: sham operation group (sham, n=10), ovariectomy (OVX) group (n=10), and OVX with EZW treatment group (EZW group, n=10). From one week after ovariectomy, EZW (100 mg/mL) or vehicle (distilled water) was fed (1 mL/100 g) once per day for 12 weeks until the sacrifice of the rats. The body weights were measured weekly. After sacrifice, the sera and mandible were collected and routinely prepared for the measurement of alveolar trabecular microarchitecture, serum levels of E2, bone-specific alkaline phosphatase (BALP) and tartrate-resistant acid phosphatase 5b (TRAP5b), as well as mandibular mRNA expression of Wnt/ß-catenin signaling pathway molecules wnt3a, low-density lipoprotein receptor-related protein 5 (LRP5), ß-catenin and dickkopf homolog 1 (DKK1). The results showed that EZW treatment significantly prevented the body weight gain, degradation of alveolar trabecular microarchitecture and alveolar bone loss in the OVX rats. Furthermore, we observed that EZW could increase the serum levels of E2 and BALP, and decrease levels of serum TRAP5b in EZW group compared with vehicle group. In addition, RT-PCR results revealed that EZW upregulated the expression levels of wnt3a, LRP5 and ß-catenin, and reduced the expression of DKK1 in OVX rats. Taken together, our results suggested that EZW may have potential anti-osteoporotic effects on osteoporotic alveolar bone by stimulating Wnt/LRP5/ß-catenin signaling pathway.

Effects of traditional Chinese medicine on bone remodeling during orthodontic tooth movement.

ETHNOPHARMACOLOGICAL RELEVANCE: Dipsacus asper Wall (Dipsacaceae), Salvia miltiorrhiza (Salvia) and Drynaria fortunei (Drynaria) have been traditionally used in Chinese medicine as the main ingredient of many formulations for the treatment of cardiovascular and inflammatory diseases. AIM OF THE STUDY: This study was aimed to evaluate the effect of the traditional Chinese medicine (TCM) Dipsacaceae, Salvia and Drynaria on bone remodeling during orthodontic tooth movement (OTM). SETTING: This study was conducted in School of Stomatology, Shandong University between 2009 and 2010 [Jinan, Shandong, China]. MATERIALS AND METHODS: Ninety-six eight-week-old female SPF Wistar rats 180-200 g were selected and randomly divided into four groups of 24: Dipsacaceae group, Salvia group, Drynaria group and control group. Animal models for orthodontic tooth movement were then established which consisted of a closed coil spring ligated to the upper first molar and incisors, exerting a force of 40 g during the experimental period. Rats in the TCM groups were given Dipsacaceae, Salvia and Drynaria decoction respectively by intragastric administration 6 g/kg/day and the control group were given normal saline 3 ml. The rats were sacrificed in batch on the 7th, 14th, 21st and 28th days after orthodontic treatment. Slices from periodontium of the upper first molar were observed under optical microscope. Neovascularization, new bone formation and osteoclast number were observed. RESULTS: The upper first molars were drawn mesial by the force. Telangiectasia and new bone formation in periodontal tissue were significantly in the TCM groups compared with the control group. Application of orthodontic forces in the experimental teeth showed a significant increase (P<0.05) of osteoclast number in the TCM group when compared with the control group. In addition, the number of osteoclast had no significant differences among the TCM groups (P>0.05). Osteoclast number in the TCM group and the control group were 10.12±0.058, 10.13±0.022, 10.09±0.047 and 9.55±0.045, respectively. CONCLUSIONS: These findings suggest that the TCM decoction are beneficial to the alveolar bone remodeling by promoting osteoclast differentiation during OTM.

Low-energy laser irradiation facilitates the velocity of tooth movement and the expressions of matrix metalloproteinase-9, cathepsin K, and alpha(v) beta(3) integrin in rats.

It has previously been reported that low-energy laser irradiation stimulated the velocity of tooth movement via the receptor activator of nuclear factor kappa B (RANK)/RANK ligand and the macrophage colony-stimulating factor/its receptor (c-Fms) systems. Matrix metalloproteinase (MMP)-9, cathepsin K, and alpha(v) beta(3) [alpha(v)beta3] integrin are essential for osteoclastogenesis; therefore, the present study was designed to examine the effects of low-energy laser irradiation on the expression of MMP-9, cathepsin K, and alpha(v)beta3 integrin during experimental tooth movement. Fifty male, 6-week-old Wistar strain rats were used in the experiment. A total force of 10g was applied to the rat molars to induce tooth movement. A Ga-Al-As diode laser was used to irradiate the area around the moving tooth and, after 7 days, the amount of tooth movement was measured. To determine the amount of tooth movement, plaster models of the maxillae were made using a silicone impression material before (day 0) and after tooth movement (days 1, 2, 3, 4, and 7). The models were scanned using a contact-type three-dimensional (3-D) measurement apparatus. Immunohistochemical staining for MMP-9, cathepsin K, and integrin subunits of alpha(v)beta3 was performed. Intergroup comparisons of the average values were conducted with a Mann-Whitney U-test for tooth movement and the number of tartrate-resistant acid phosphatase (TRAP), MMP-9, cathepsin K, and integrin subunits of alpha(v)beta3-positive cells. In the laser-irradiated group, the amount of tooth movement was significantly greater than that in the non-irradiated group at the end of the experiment (P < 0.05). Cells positively stained with TRAP, MMP-9, cathepsin K, and integrin subunits of alpha(v)beta3 were found to be significantly increased in the irradiated group on days 2-7 compared with those in the non-irradiated group (P < 0.05). These findings suggest that low-energy laser irradiation facilitates the velocity of tooth movement and MMP-9, cathepsin K, and integrin subunits of alpha(v)beta3 expression in rats.

Effects of hyperbaric oxygen on proliferation and differentiation of osteoblasts from human alveolar bone.

In view of the controversy of the clinical use of hyperbaric oxygen (HBO) treatment to stimulate fracture healing and bone regeneration, we have analyzed the effects of daily exposure to HBO on the proliferation and differentiation of human osteoblasts in vitro. HBO stimulated proliferation when osteoblasts were cultured in 10% fetal calf serum (FCS), whereas an inhibitory effect of HBO was observed when cultures were supplemented with 2% FCS. On the other hand, HBO enhanced biomineralization with an increase in bone nodule formation, calcium deposition, and alkaline phosphatase activity, whereas no cytotoxic effect was detected using a lactate dehydrogenase activity assay. The data suggest that the exposure of osteoblasts to HBO enhances differentiation toward the osteogenic phenotype, providing cellular evidence of the potential application of HBO in fracture healing and bone regeneration.

Effect of interleukin-1beta on transforming growth factor-beta and bone morphogenetic protein-2 expression in human periodontal ligament and alveolar bone cells in culture: modulation by avocado and soybean unsaponifiables.

BACKGROUND: In periodontal disease, interleukin-1beta (IL-1beta) is responsible for the matrix breakdown through excessive production of degrading enzymes by periodontal ligament fibroblasts and osteoblasts. Transforming growth factor-beta (TGF-beta) plays an important role in tissue regeneration as one of the factors capable of counteracting IL-1beta effects. In this study, we investigated the in vitro effect of avocado and soya unsaponifiables (ASU) on the expression of TGF-beta1, TGF-beta2, and bone morphogenetic protein-2 (BMP-2) by human periodontal ligament (HPL) and human alveolar bone (HAB) cells in the presence of IL-1beta. METHODS: HPL and HAB cells were incubated for 48 hours with ASU (10 microg/ml) in the presence or absence of IL-1beta (10 ng/ml). The steady-state levels of TGF-beta1, TGF-beta2, and BMP-2 mRNAs were determined by Northern blot or reverse transcription-polymerase chain reaction (RT-PCR). The amounts of TGF-beta1 and TGF-beta2 proteins were measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: The data indicated that IL-1beta strongly decreases the expression of TGF-beta1 and TGF-beta2 by HPL cells. ASU were capable of opposing the cytokine effect. In HAB cells, TGF-beta1 and BMP-2 mRNA levels were downregulated by the cytokine. ASU were found to reverse the IL-1beta-inhibiting effect. In contrast, the cytokine stimulated the production of TGF-beta2 in alveolar bone cells, with no significant effect of ASU. CONCLUSIONS: The results indicate that the IL-1beta-driven erosive effect in periodontitis could be enhanced by a decreased expression of members of the TGF-beta family. The ASU stimulation of TGF-beta1, TGF-beta2, and BMP-2 expression may explain their promoting effects in the treatment of periodontal disorders, at least partly. These findings support the hypothesis that ASU could exert a preventive action on the deleterious effects exerted by IL-1beta in periodontal diseases.

Effects and mechanism of hyperbaric oxygen on prostaglandins in alveolar bone and gingival of experimental periodontitis in animal.

OBJECTIVE: To study the effects and the therapeutic mechanism of hyperbaric oxygen (HBO) on prostaglandin E(2) (PGE(2)) in alveolar bone and gingiva of experimental periodontitis in animal. METHODS: Experimental periodontitis was produced by silk thread sutures combined with high content sugar diet. For HBO therapy, they were exposed to a pressure of 0.25 MPa (2.5ATA), breathing pure oxygen one session a day for 60 min. The treatment course was 2 weeks. The value of PGE(2) in gingiva and alveolar bone was analyzed by enzyme immunoassay (EIA). RESULTS: The value of PGE(2) in gingiva of control group was 3.21 ng/g, and that of PGE(2) in alveolar bone was 3.22 ng/g. The contents of PGE(2) in gingiva (13.96 ng/g) and alveolar bone (13.32 ng/g) of periodontitis group increased markedly than control group (P < 0.01). The contents of PGE(2) in gingiva (5.21 ng/g) of HBO group were 62.7% which was lower than that of periodontitis group, and the value of PGE(2) in alveolar bone (4.05 ng/g) were 69.6% lower than that of periodontitis group. The difference of PGE(2) in gingiva or alveolar bone was significant for the HBO group and periodontitis group (P < 0.01). CONCLUSIONS: The contents of PGE(2) in alveolar bone and gingiva increased markedly when experimental periodontitis has formed. The value of PGE(2) in alveolar bone and gingiva reduce markedly after HBO exposure, and the decreased rate of PGE(2) in alveolar bone is more evident than that of PGE(2) in gingiva after HBO therapy.

[A study on expression of basic fibroblast growth factors in periodontal tissue following orthodontic tooth movement associated with low power laser irradiation].

OBJECTIVE: The purpose of this study was to investigate the effects of low power laser on basic fibroblast growth factors (bFGF) expression in periodontal tissue during tooth movement. METHODS: 18 white rabbits were randomly divided into 6 groups with 3 rabbits in each group, including groups of 1, 3, 5, 7, 14 and 21 days. Under an anesthesia condition by 2% pentobarbital sodium, the stainless coil springs were fixed between the first maxillary molar and the incisor producing the force of 80 g. The right side of maxilla was considered as the experimental group under the irradiation of low power laser with the left side as the control groups. The expression of bFGF was investigated half-quantitatively through immunohistochemical analysis. RESULTS: The expression of bFGF in periodontal tissue with irradiation of low power laser was higher than the control side. There were significant differences among the 5, 7, and 14 day groups. In the tension area of the experimental side, the expression of bFGF in the osteoblastic surface of alveolar bone was characteristically greater than that of the control side. CONCLUSION: The laser of low power promotes the expression of bFGF in the periodontal tissue and alveolar bone remodeling.

[The experimental study about the relations between Chinese herb-epimedium leptorrhizum stearn (CH-ELS) and endogenous cAMP in alveolar bone of orthodontic tooth in rats].

The aim of this study was, to explore the mechanism of CH-ELS promoting bone remodelling of orthodontic tooth in rats. 11 male sprague-Dawleg rats was divided into 3 groups. Group I (normal control group) Group II (applied force, no injection) Group III (applied force, injection). The experimental period was 3 days. The radioimmunoassay (RIA) method were used to investigate the effects of CH-ELS on the content of endogenous cAMP in alveolar bone of orthodontic tooth in rats. Results indicate that CH-ELS has no significant effects on endogenous cAMP in alveolar bone of orthodontic tooth, perhaps, cAMP were not involved to regulate the mechanism of CH-ELS promoting bone remodelling. To explore the mechanism of bone remodelling of orthodontic tooth is more significant in orthodontic clinic.

In situ hybridization shows Dmp1 (AG1) to be a developmentally regulated dentin-specific protein produced by mature odontoblasts.

Acidic phosphorylated proteins are prominent constituents of the extracellular matrix of bone and dentin. It has been postulated that they may have important structural and regulatory roles in the process of tissue mineralization. Studies of a cDNA library, prepared from cells of the rat incisor odontoblast-pulp complex of 3 week old Sprague-Dawley rats, led to the identification of a serine-rich acidic protein, designated AG1, which appeared to be a dentin matrix component. In order to determine which cells of the odontoblast-pulp complex were responsible for the making of AG1, in situ hybridization was carried out using digoxigenin-labeled probes. The full length AG1 cDNA was subcloned into the pBluescript vector, which contains two strong promoters, T3 and T7. The sense and antisense complementary RNA (cRNA) hybridization probes were prepared by in vitro transcription using T3 and T7 polymerases in the presence of 11-dUTP. Incisor sections were obtained from rat embryos at days 16, and 20, and newborns at days 2 and 5. No AG1 mRNA was detected in the embryonic sections, but digoxigenin labeling was evident in odontoblasts secreting mineralizing dentin at postnatal days 2 and 5. Sense probes showed no hybridization. Pulp cells, Meckel's cartilage, and alveolar bone were free of hybridization with the antisense probe. Unexpectedly, a low level of digoxigenin staining was seen in the cytoplasm of secretory ameloblasts, but not in the preameloblasts, stratum intermedium or stellate reticulum of the enamel organ. These data show that AG1 expression is regulated developmentally and is restricted to secretory stage mature odontoblasts.

Effects of fluoride intake on the mineral content, acid solubility and resorption caused by experimental periodontitis of rat alveolar bone.

Adult rats were given either distilled water or drinking water containing 100 parts/10(6) of fluoride. The alveolar bone of rats given fluoride for 90 days showed an increased mineral content and decreased acid solubility compared to the bone of rats given distilled water. Experimental periodontitis was initiated in both groups after 110 days of treatment to cause alveolar bone resorption. Fourteen days later, the rats were killed and it was found that the alveolar bone resorption caused by experimental periodontitis was significantly smaller in the rats given fluoride in their drinking water than in those given distilled water. The findings suggest that fluoride intake might have a protective effect on rapidly progressing alveolar bone resorption.

[The effect of different vacuum therapy regimens on protein and mineral metabolism in periodontal tissues]. / Vliianie razlichnykh rezhimov vakuumnoi terapii na belkovyi i mineral'nyi obmen v tkaniakh parodonta.

Radionuclide label was used to study the effects of various vacuum therapy schemes on the protein and mineral metabolism in periodontal tissues. Vacuum therapy was found to normalize Ca, P, and protein metabolism in spontaneous atrophy of the alveolar processes in white rats. Focal dosed vacuum was found the most effective. These data will be used to develop a complex of measures to prevent atrophies of the maxillary alveolar processes.

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.

Differences in permeability of microperoxidase and horseradish peroxidase into the alveolar bone of developing rats.

Microperoxidase (small m.wt tracer) and horseradish peroxidase (large m.wt tracer) were used to investigate the existence of extracellular (between blood vessels and bone cells) and intracellular transport pathways in the alveolar bone cells of five-day-old rats. HRP directly penetrated the cytoplasm and nucleus of the osteocytes and osteoblasts, but MP did not. These findings suggest that HRP at high dosages is more toxic to bone cells than is MP, since the direct penetration of HRP probably results from alteration of plasma membrane permeability. If so, MP seems to be a more suitable tracer than HRP. The findings from MP tracing suggest that a main transport pathway of bone fluid exists between the external part of the unmineralized zone, which is located in the lacunar and canalicular spaces around bone cells, and the innermost edge of the mineralized matrix, which constitutes the lacunar and canalicular walls; in addition, minor pathways as accessory routes might diverge from the main pathway to go around the bone cells.

Intraligamentary--intraosseous anesthesia. A radiographic demonstration.

Intraligamentary dental anesthesia has become a widely accepted technique. The periodontal ligament seems to provide easy access to the tooth apex. In the present study, radiopaque material was injected into baboon monkeys. Serial radiographs during incremental injections showed clouding of the crestal bone. The material was seen gradually advancing through the alveolar bone crest, apically. The spread was noticed through the marrow spaces, unexpectedly avoiding the PDL route.