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.     

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.     

Contribution of the periosteum to bone formation in guided bone regeneration. A study in monkeys

The periosteum has been referred to as a protective barrier in the regeneration of bone defects. The objective of this study was to determine the contribution of periosteum as a natural barrier to bone formation in guided bone regeneration. Mucoperiosteal flaps were elevated bilaterally on the buccal aspect of the mandibular angle in 5 cynomolgus monkeys. Bleeding was induced by perforating the cortical bone. A hemispherical titanium mesh was fixed over the areas thus creating a void 5 mm in height between the mesh and the bone surface. One one side the mesh was covered with an ePTFE membrane (test side). The contralateral side did not receive further treatment (control side). After 4 month healing, histomorphometric analyses were used to determine the percentage of new bone in the void underneath the mesh, and the ratio between mineralized tissue and marrow spaces in new and old bone. The mean percentage of new bone tissue was 77.2 +/- 7.5% for the test sides and 68.6 +/- 8.4% for the control sides (P = 0.018, t-test). This new bone contained 80.0 +/- 3.6% mineralized tissue in the test group and 82.5 +/- 5.0% in the control group (P > 0.05, t-test). In both groups the newly formed bone exhibited significantly less mineralized tissue than the old bone (P < 0.05, t-test). It is concluded from this study that new bone formation was enhanced by the additional use of an ePTFE membrane under a periosteum-lined mucoperiosteal flap when space maintenance was excluded as a critical factor.     

Dental follicle cell-conditioned medium enhances the formation of osteoclast-like multinucleated cells

An influx of mononuclear cells and the subsequent increase of osteoclasts around tooth germs suggests that the dental follicle (DF) regulates or influences bone resorption required for tooth eruption. In order to study the effects of DF cell products on osteoclast formation during tooth eruption, a conditioned medium (CM) was created in which DF cells were added to mouse bone marrow cultures. Tartrate-resistant acid phosphatase (TRAP)-positive osteoclast-like multinucleated cells were formed in the presence of 10 nM 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. The CM, dose-dependently, stimulated the formation of TRAP-positive cells in the presence of 1,25(OH)2D3 for 14 days culture. The number of these cells decreased due to degradation in the control culture. A semi-solid methylcellulose assay in the presence of CM showed little expression of colony-stimulating activity. These results suggest that the DF cells of a developing tooth produce factor(s) that enhance osteoclast formation and bone resorption necessary for tooth eruption.     

Setting global goals for oral health for the year 2010

OBJECTIVE: To discuss the determinants for the possible setting of global goals for oral health for the year 2010. RESULTS AND CONCLUSIONS: If the application of oral health goals is to measure the outcome of oral health strategies and plans, they need to be substantially redesigned to reflect disparities in oral health and access to oral health care. It is no longer acceptable to focus only upon one or two arbitrarily selected disease entities and say these reflect the oral well-being of communities and the success (or failure) of oral health programmes. The use of validated socio-dental indicators to assess prevalence of socio-dental impacts seems essential, as does the avoidance of goals for conditions that are strongly influenced by culture, class, ethnicity and other widely variable local influences.     

Electroreduction of methyl viologen in the presence of nitrite. Its influence on enzymatic electrodes

The electroreduction of methyl viologen (MV) in the presence of nitrite was studied by cyclic voltammetry. A catalytic wave for the reduction of MV²⁺ was observed at ?0.740 V for which an EC catalytic mechanism is proposed. The rate constant for this chemical reaction under pseudo-first-order conditions, evaluated using working curves, was employed in the simulation of the voltammetric response. The second-order rate constant was also evaluated. Influences of the reaction at ?0.800 V on enzymatic electrodes employing nitrate reductase (NR) and MV⁺ as mediator were also analysed by chronoamperometry.     

Purification and characterization of a trypsin-like protease from the culture supernatant of Actinobacillus actinomycetemcomitans Y4

We purified and characterized a protease from Actinobacillus actinomycetemcomitans. The protease was isolated from the culture supernatant by sonication in phosphate-buffered 3-[(3 cholamidopropyl)dimethylammonio]-1-propanesulfonate (CHAPS). The protease was purified by acetone precipitation, followed by column chromatography with Arginine Sepharose 4B, DEAE Sepharose CL-6B, Sephacryl S-200HR and HiTrap Q. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified protease showed a clear band at approximately 50 kDa. The protease showed trypsin-like activity with hydrolytic activity for the synthetic substrates N alpha-benzoyl-DL-arginine p-nitroanilide (BApNA) and N alpha benzoyl-DL-lysine p-nitroanilide (BLpNA). The activity of the protease was stable at pH 7.0 to approximately 8.0. The activity of the protease was inhibited by leupeptin, phenylmethylsulfonyl fluoride (PMSF), and EDTA, but was not affected by dithiothreitol (DTT), cysteine, 2-mercaptoethanol, pepstatin or soybean trypsin inhibitor. These data suggest that this protease is a serine protease or metallo protease. This enzyme extensively degraded collagen type I and fibronectin.     

Solubility and fluoride release in ionomers and compomers.

OBJECTIVE: The degree of solubility and the fluoride release of glass-ionomer cements and "compomers" were determined as a function of time. METHOD AND MATERIALS: Three conventional glass-ionomer cements, three hybrid ionomers, and two compomers were included in the study. Disk-shaped specimens were prepared and immersed in a lactic acid solution. Solubility was evaluated from determinations of loss of mass as a function of time. To evaluate fluoride release, similar specimens were immersed in 50 mL of deionized water to which 50 mL of buffer solution was added. A fluoride ion detector was used to read the concentration of fluoride ion in the overall solution at different times after immersion. RESULTS: Material and time factors had a significant influence on results. The compomers showed less corrosion and fluoride release than the ionomers. Some correlation was found between solubility and fluoride leakage values. CONCLUSION: Components of both the ionomers and compomers that were studied can dissolve in water. The materials leak fluoride ions in amounts that differ according to the characteristics of the individual products.