Butyric acid induces apoptosis in inflamed fibroblasts

Butyric acid, an extracellular metabolite from periodontopathic bacteria, induces apoptosis in murine and human T- and B-cells, whereas intact gingival fibroblasts isolated from healthy humans are resistant to butyric-acid-induced apoptosis. We examined the susceptibility of inflamed gingival fibroblasts isolated from adult persons with periodontitis to butyric-acid-induced apoptosis. Butyric acid significantly suppressed the viability of inflamed gingival fibroblasts and induced apoptosis in a dose-dependent manner. The incubation of inflamed gingival fibroblasts with butyric acid induced DNA fragmentation and apoptotic changes such as chromatin condensation, hypodiploid nuclei, and mitochondrial injury. Furthermore, butyric-acid-induced apoptosis in inflamed gingival fibroblasts was reduced by caspase-3/7, -6, -8, and -9 inhibitors. Thus, inflamed gingival fibroblasts from adult persons with periodontitis appear to be highly susceptible to mitochondria- and caspase-dependent apoptosis induced by butyric acid, compared with healthy gingival fibroblasts.     

Vertical distraction of a free vascularized osteocutaneous scapular flap in the reconstructed mandible for implant therapy

This paper describes a case of vertical distraction osteogenesis of a free vascularized osteocutaneous scapular flap in the reconstructed mandible before implant therapy. The patient was a 67-year-old woman with squamous cell carcinoma of the right lower gingiva. She underwent segmental mandibulectomy for tumor ablation and reconstruction with an osteocutaneous scapular flap. The distraction protocol, clinical course and implant therapy are presented. Through this procedure, the bone height of the scapular graft increased by 10mm. Implants with adequate length could be placed in the distracted area. Two years after masticatory loading, the condition of these implants was stable. Vertical distraction osteogenesis of the scapular flap was considered effective when performed before implant therapy, to facilitate postoperative functional and esthetic restoration after tumor resection.     

A comparison of two methods for the evaluation of the daily urinary fluoride excretion in Romanian pre-school children

OBJECTIVE: To compare two different methods of estimating daily fluoride urinary excretion in pre-school children under stable fluoride intake conditions. DESIGN: Thirty-five healthy kindergarten children, permanent residents of Targu-Mures, Romania, where the average drinking water fluoride concentration is 0.12 mg F/L, participated on two separate occasions, when they were aged 4-6 and 5-7 years, respectively in the collection of a) a mid-morning spot urine sample and b) a 16-h time-controlled urine sampling. In case a), the ratio of concentrations of fluoride and creatinine were measured, while in case b) the rates of fluoride excretion in two separate 8-hour periods were used to estimate the 24-hour fluoride urinary excretion. RESULTS: The estimated average daily fluoride urinary excretion values (S.D.) were 0.318 (0.182) mg F/day for method a) and 0.341 (0.193) mg F/day for method b). These values were not significantly different (Mann-Whitney U test; p = 0.49). The estimated daily fluoride doses were 0.040 (0.021) and 0.043 (0.022) mg F/kg body weight/day, respectively. The latter values were not significantly different (Mann Whitney U test; p = 0.38). CONCLUSIONS: Results obtained suggest that under stable F-intake conditions the estimation of the daily fluoride urinary excretion by means of a mid-morning spot urine sample yields comparable results to those obtained with the more involved method of separate, two 8 h (16 h) time-controlled urine sampling recommended by the WHO. Use of spot urine sampling appears to be particularly useful for epidemiological studies.     

Salivary spinability and periodontal disease progression in an elderly population

OBJECTIVE: To explore the relationship between the spinability of stimulated whole saliva and periodontal disease progression over 12 months in an elderly population. METHODS: Three hundred and thirty-two subjects aged 76 years at baseline were studied. Attachment loss was calculated on a site-by-site basis, and periodontal disease progression was defined as an attachment loss of >/=3mm. Stimulated whole saliva was collected and salivary spinability (SS) was measured. A multiple linear regression analysis was performed to assess the relationship between periodontal disease progression and SS after controlling for other covariates. The independent variables were selected from those which had significant relationships with disease progression in the bivariate analyses. RESULTS: Mean SS was 1.94+/-0.42mm in males and 1.88+/-0.32mm in females; this difference was not significant. Simple linear regression analysis showed a significant positive relationship between periodontal disease progression and SS (P=0.026), whereas there was no significant relationship between periodontal disease progression and salivary flow rate. Multiple regression analysis revealed a significant positive relationship between periodontal disease progression and SS (P=0.024) after controlling for the number of remaining teeth and baseline periodontal conditions. The model explained 15.5% of the variance in the percentage of sites where the disease had progressed. CONCLUSIONS: These findings suggest that elderly subjects with viscous saliva are prone to periodontal disease progression.     

The susceptibility of bleached enamel to staining as measured by Quantitative Light-induced Fluorescence (QLF)

OBJECTIVES: To report the use of Quantitative Light-induced Fluorescence (QLF) to determine if there was a tendency for bleached enamel to take up extrinsic stains more than unbleached enamel. METHODS: Bovine teeth devoid of stains were selected, the roots removed and enamel gently pumiced. Each tooth was sectioned into two and each half randomly assigned to two groups (bleached or unbleached). Windows were created on each half using clear acid resistant varnish. 38% Hydrogen peroxide gel was applied to the exposed windows of the bleached group for 1 hour. The teeth were rinsed and dried. Bleached and unbleached halves of the same teeth were then mounted on glass rods attached to pot lids using green stick. QLF images were taken. The teeth were subjected to a cycle of artificial saliva, chlorhexidine and tea (2 minutes in each solution). This was repeated 5 times. QLF images were taken at the end of each cycle. RESULTS: The uptake and progression of stain was detected in all the sections by QLF. Using paired t- test (SPSS) there was no significant difference between the two groups for the change from baseline to the final stain cycle (p > 0.05), however there was variability in stain uptake within the groups as the cycles progressed. CONCLUSION: Bleaching of enamel in vitro does not appear to increase the susceptibility of enamel to extrinsic staining.     

Platelet-derived growth factor-B gene delivery sustains gingival fibroblast signal transduction

Background and Objective: Platelet‐derived growth factor‐BB is a potent mediator of tooth‐supporting periodontal tissue repair and regeneration. A limitation of the effects of topical platelet‐derived growth factor‐BB application is its short half‐life in vivo. Gene therapy has shown strong promise for the long‐term delivery of platelet‐derived growth factor in both skin ulcer healing and periodontal tissue engineering. However, little is known regarding the extended effects of platelet‐derived growth factor‐B on cell signaling via gene delivery, especially at the level of phosphorylation of intracellular kinases. This study sought to evaluate the effect of gene transfer by Ad‐PDGF‐B on human gingival fibroblasts (HGFs) and the subsequent regulation of genes and cell‐surface proteins associated with cellular signaling. Material and Methods: HGFs from human subjects were treated by adenoviral PDGF‐B, PDGF‐1308 (a dominant negative mutant of PDGF) and recombinant human platelet‐derived growth factor‐BB, and then incubated in serum‐free conditions for various time points and harvested at 1, 6, 12, 24, 48, 72 and 96 h. Exogenous PDGF‐B was measured by RT‐PCR and Western blot. Cell proliferation was evaluated by [methyl‐³H]thymidine incorporation assay. We used proteomic arrays to explore phosphorylation patterns of 23 different intracellular kinases after PDGF‐B gene transfer. The expression of α and β PDGFR and Akt were measured by Western blot analysis. Results: Sustained in vitro expression of PDGF‐B in HGFs by Ad‐PDGF‐B transduction was seen at both the mRNA and protein levels. Compared to rhPDGF‐BB and Ad‐PDGF‐1308, Ad‐PDGF‐B maintained cell growth in serum‐free conditions, with robust increases in DNA synthesis. Gene delivery of PDGF‐B also prolonged downregulation of the growth arrest specific gene (gas) PDGFαR. Of the 23 intracellular kinases that we tested in proteomic arrays, Akt revealed the most notable long‐term cell signaling effect as a result of the over‐expression of Ad‐PDGF‐B, compared with pulse recombinant human platelet‐derived growth factor BB. Prolonged Akt phosphorylation was induced by treatment with Ad‐PDGF‐B, for at least up to 96 h. Conclusion: These findings further demonstrate that gene delivery of PDGF‐B displays sustained signal transduction effects in human gingival fibroblasts that are higher than those conveyed by treatment with recombinant human platelet‐derived growth factor‐BB protein. These data on platelet‐derived growth factor gene delivery contribute to an improved understanding of these pathways that are likely to play a role in the control of clinical outcomes of periodontal regenerative therapy.     

Crouzon syndrome with acanthosis nigricans: case report and mutational analysis.

OBJECTIVE: To describe the 22nd case of Crouzan syndrome with acanthosis nigricans, a hyperkeratotic skin disorder with hyperpigmentation. METHODS: DNA analysis and sequencing of the FGFR3 gene were performed. RESULTS: The 13-year-old Japanese boy described here also had dyspnea, facial palsy, sensorineural hearing loss, and skeletal and mental retardation. Examination of a skin biopsy specimen revealed the typical findings of acanthosis nigricans. Genetic analysis revealed the Ala391Glu mutation in one FGFR3 gene. CONCLUSIONS: Crouzon syndrome with acanthosis nigricans is a distinct clinical entity different from classic Crouzon syndrome.     

Gene expression and immunolocalization of amelogenin in enamel hypoplasia induced by successive injections of bisphosphonate in rat incisors

Successive injections of 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) in rats induce enamel hypoplasia. To elucidate the pathogenesis of this hypoplasia, male Wistar rats were daily injected with HEBP or physiological saline for 7 days. After the last injection, they were killed under anaesthesia and their maxillary incisors were examined using an in situ hybridization technique and immunohistochemical staining to detect the gene expression and localization of amelogenin protein, respectively. In the HEBP-injected rats, several islets of partially mineralized enamel were present along crown-analogous surface of the incisor in the secretory stage of amelogenesis and enamel-free zones existed between these islets. In situ hybridization demonstrated amelogenin gene expression over the ameloblasts facing the islets of the matrix enamel as well as over those of the enamel-free zones. Immunohistochemical studies using rabbit antiamelogenin antibody revealed positive reaction both in the enamel matrix of the control group and in the islets of enamel matrix of the HEBP-injected group. Some small granules immunoreactive to amelogenin antibody were found in the distal portions of the ameloblasts in the HEBP-injected rats. The results indicate that HEBP does not alter amelogenin gene expression over ameloblasts, or the protein's existence in enamel matrix. There appeared to be some accumulation of amelogenin in the HEBP-treated ameloblasts. It is therefore suggested that the enamel hypoplasia in this experiment may not be due to a disturbance in amelogenin synthesis but to a disturbance in a later process, presumably of protein secretion.     

Orthopedic cervical headgear with an expanded inner bow in class II correction

Forty consecutively referred children, 20 boys and 20 girls, with a Class II division I malocclusion and protrusive maxilla were treated with orthopedic cervical headgear with a 10 mm expanded inner bow and a long outer bow bent 15 degrees upwards. The mean age of the children at the beginning of treatment was 9.3 years (SD 1.3, range 6.6 to 12.4 years), and the average treatment time was 1.8 years (SD 0.6, range 0.8 to 3.1 years). In all patients Class II molar relationships were successfully corrected to Class I molar relationships. This was accompanied by a marked widening of both maxillary and mandibular dental arches. The cephalometric analysis suggested that the observed improvement of the occlusion was due to an inhibition of forward growth of the maxilla and anterior downward rotation of the palate.