Several studies have demonstrated a close association between Streptococcus (S.) anginosus infection and head and neck cancer. Accumulation of 8-hydroxy-deoxyguanosine (8-OHdG), which may result from the continuous generation of reactive oxygen species associated with chronic inflammation, has been reported in human preneoplastic lesions and in cancerous tissues. The purpose of the present investigation was to assess the salivary levels of S. anginosus and 8-OHdG in patients with periodontitis. Salivary levels of S. anginosus were measured by realtime PCR. S. anginosus was detected in 28 out of 38 (73.7%) of subjects. The 8-OHdG level was significantly higher in patients positive for S. anginosus than in patients negative for the bacterium. A significant decrease in S. anginosus and 8-OHdG levels was observed after initial periodontal treatment. Our findings indicate that, although the levels of S. anginosus are relatively low, there is a correlation between the salivary level of S. anginosus and 8-OHdG, and that periodontal treatment can decrease the levels of these hazard factors.
The role of GABAA and GABAB receptors in the core of the nucleus accumbens in turning behavior of rats was investigated. Unilateral injections into the core of the nucleus accumbens of the GABAA receptor agonist (muscimol, 50 ng) and antagonist (bicuculline, 200 ng), and the GABAB receptor agonist (baclofen, 100 ng) and antagonist (2-hydroxysaclofen, 2 μg) did not produce turning behavior. In rats pretreated with unilateral injections of the dopamine D1-like/D2-like receptor antagonist, cis (Z) -flupentixol (10 pg), into the ventrolateral striatum and saline into the nucleus accumbens core of contralateral side, systemic injection of a mixture of dopamine D1-like (SKF 38393, 3 mg/kg) and D2-like (quinpirole, 1 mg/kg) receptor agonists has been found to elicit contraversive pivoting, namely pivoting away from the side of the core injection. This dopamine D1-like/D2-like receptor-mediated pivoting was significantly inhibited by injections into the core of the nucleus accumbens of muscimol (50 ng), but not bicuculline (200 ng). In contrast, the dopamine D1-like/D2-like receptor-mediated pivoting was suppressed by either baclofen (100 ng) or 2-hydroxysaclofen (2 pg) injected into the nucleus accumbens core. It is therefore concluded that neither GABAA nor GABAB receptor stimulation in the core of the nucleus accumbens produces turning behavior, and that GABAA, but not GABAB, receptors in the nucleus accumbens core may modulate dopamine D1-like/D2-like receptor-mediated pivoting. (J Oral Sci. 45, 185-192, 2003)
The decline of dental caries in the industrialized countries can be attributed to widespread use of fluorides. The Japanese market share of dentifrices containing fluorides has increased from 12% in 1985 to 77% in 2000. For a fluoride dentifrice to be effective in the control of dental caries, an adequate concentration of the fluoride must be soluble. Several Japanese fluoride dentifrices have in their formulations calcium phosphate as an abrasive, which may react with fluoride. This study was designed to evaluate the availability and stability of fluoride in the most consumed dentifrices in Japan. The analyses were made when the dentifrices were purchased (fresh samples) and after one year of storage (aged samples) at room temperature (21.8 ± 3.6°C). Total fluoride and soluble fluoride was determined using an ion specific electrode. All dentifrices showed similar concentrations of total fluoride in fresh and aged samples in accordance with the Japanese Legislation (content of less than 1, 000 ppm F). Some dentifrices, with dicalcium phosphate as abrasive, showed decreasing concentrations of total soluble fluoride and increasing amounts of insoluble fluoride over time. Although most of the Japanese fluoridated dentifrices evaluated in this study contain unstable fluoride, they were found to have sufficient concentrations of soluble fluoride to be effective in preventing dental caries.
The aqueous extracts of Piper betle and Psidium guajava were prepared and tested for their antiadherence effect on the adhesion of early plaque settlers (Strep. mitis, Strep. sanguinis and Actinomyces sp.). The saliva-coated glass surfaces were used to simulate the pellicle-coated enamel surface in the oral cavity. Our results showed that the anti-adherence activities of Piper betle and Psidium guajava extracts towards the bacteria were different between the bacterial species. Psidium guajava was shown to have a slightly greater anti-adherence effect on Strep. sanguinis by 5.5 % and Actinomyces sp. by 10 % and a significantly higher effect on Strep. mitis (70%) compared to Piper betle. The three bacterial species are known to be highly hydrophobic, and that hydrophobic bonding seemed to be an important factor in their adherence activities. It is therefore suggested that the plant extracts, in expressing their anti-adherence activities, could have altered the hydrophobic nature of the bonding between the bacteria and the saliva-coated glass surfaces.
This paper reports the results of experimental use of glass-ionomer microimplants in the augmentation of the maxillary alveolar ridge in dogs. The study included ten adult mongrel dogs 5 years of age, weighing between 50 and 70 pounds (25-30 kg), divided into 2 groups of 5 dogs each. In both groups, the maxillary 4th premolar and 1st molar were removed after the elevation of a buccal mucoperiosteal flap. The alveolar bone adjacent to the extracted teeth was also removed. In the experimental group (5 dogs), Ionogran® a glass-ionomer microimplants (GIMIs) (Ionogran® particle size of 0.5-1.0 mm, IONOS Medizinische Produkte GmbH & Co. KG, D-8031 Seefeld, Gemany) were used for augmentation and were inserted in the created defects. The extraction sockets and bone defects were augmented with an average amount of 2 g of GIMIs. In the control group, the bone defects were left unfilled as a control for bone healing. Histological examination showed that the glass-ionomer microimplants were extremely osteoconductive and inert materials. Stimulation of growth of new bone tissue in contact with the glassionomer microimplants was evident. No inflammatory cells were detected on or adjacent to the GIMIs. In the control group, incomplete bone healing with fibrous scar tissue and inflammatory cells was noted. These results indicate that glass-ionomer microimplants represent highly osteoconductive and biocompatible materials for use in bone surgery.
Juveniles of the Mekong giant catfish, Pangasianodon gigas (Teleostei), have 3 sorts of toothupper and lower jaw teeth, palatal teeth, and pharyngeal teeth-but adults are toothless. To investigate the histogenesis and disappearance of the teeth, we made serial sections of the mouth and teeth of juvenile fish at 10 developmental stages (from ca. 8.5 to ca. 30 cm in total length) and examined them under scanning electron microscope and light microscope. Observations of teeth and surrounding tissues in the serial sections revealed the process of tooth resorption by active odontoclast-like cells. Numbers of jaw and palatal teeth decreased with age. When the fish reached ca. 14 cm in total length, the numbers of functional upper jaw teeth and successional tooth germs decreased rapidly, and the developmental rate of successional tooth germs slowed. When the fish reached ca. 24 cm, no teeth existed in the upper jaw. It is clear that tooth disappearance results from the shedding of functional teeth and the lack of replacement tooth germs.
We report a case of calcium pyrophosphate dihydrate (CPPD) arthropathy with condylar destruction of the temporomandibular joint. Diagnosis was made on the basis of clinical findings and x-ray evidence of severe destruction of the condyle. The most likely diagnosis was considered to be neoplasm and a secondary infection of the left TMJ. Review of sections of the condyle taken at operation confirmed the diagnosis of left TMJ pseudogout. The postoperative course was uneventful with improvement in the clinical symptoms.
A case is reported of a 66-year-old woman who could not use a conventional, full upper denture because of a gag reflex. In the maxillary alveolar ridge, restoration was performed on a moderately atrophied, edentulous anterior area and a small defect in the right-side posterior area. In the mandibular alveolar ridge, restoration was performed on a moderate osseous defect in each molar area resulting from tooth extraction due to severe periodontal disease. Based on careful treatment planning, four types of bone graft were used with previously designed osseointegrated implants. The atrophied maxillary alveolar ridge was restored with veneer iliac bone grafts to avoid fenestration during implant placement, while alveolar process deficiency was restored using inlay and sinus bone grafts as placements for long implant fixtures. The defects in the mandibular alveolar bone were filled with corticocancellous bone chips at the implant placement sites. A combination of immediate and secondary placement of Brånemark fixtures was used. Bone-anchored bridge-type implant prostheses were fitted approximately twelve months after surgery. Three years later, there had been no failure of implant fixtures and satisfactory functional and cosmetic restoration had been maintained.
The exact cause of the formation of sialoliths is unknown. Detailed knowledge of the pathogenesis of sialolithiasis is necessary to define new therapeutic procedures. The possible presence of a sphincter system in Wharton's duct has been described frequently in the context of diagnostic sialendoscopy. Serial histological examination of the entire Wharton's duct in four samples revealed no anatomical correlation for the presence of a sphincter. Secretory disturbances and viscous secretions as well as microlith formation and ductal obstruction cannot fully explain the genesis of sialoliths. The coaction of those factors with participation of bacteria leads to the development of sialoliths.