Effect of the methyl methacrylate-tributylborane sealant in preventing occlusal caries.

A newly developed pit and fissure sealant, named Enamite, was studied technologically and clinically. Major ingredients of the sealant are a solution of 3% 2-hydroxy-3-beta-naphthoxypropyl methacrylate in methyl methacrylate and poly (methyl methacrylate) powder, using tributylborane as an initiator. In comparison with other commercially available sealants, Enamite showed much greater adhesiveness to enamel, which was confirmed by scanning electron micrographic observations. The sealant was applied to 161 first molars in 99 children, aged 6-8 years, to determine the caries preventive as well as the caries retardation effect. Among the treated teeth, 98 were intact and the remaining had incipient caries. The right side teeth of each subject was assigned to the test side and the other side served as a control. Each child was evaluated every 6 months by clinical exploration and bite-wing X-ray survey. At the final examination, the electric conductivity test was also used for the caries detection. After 2 years the sealant was effective in preventing 57.1% of the occlusal caries on treated compared with control teeth. When evaluation was made by including the caries retardation effect--teeth initially carious but remaining sealed after 2 years were counted as effective--, the sealant was effective in preventing or retarding 96.3% of the occlusal caries.     

Distant metastasis of carcinoma in the maxillo-facical region--relationship to the method of therapy and TNM system.

Based upon the autopsy findings, the incidence of distant metastasis was studied to seek the relativity between the method of treatment and the TNM system at the time of initial examination on 31 cases with squamous cell carcinoma in the maxillo-facial region. The results are summarized as follows: 1) The incidence of distant metastasis among all of these cases was 58 per cent. 2) There was no significant difference in the incidence between the groups with radiation therapy and chemotherapy. 3) There was no relativity with the TNM system. 4) In the group with radiation therapy, the incidence at the "sites of the movable mucosa" was significantly higher than that at the "sites of the non-movable mucosa." 5) There was no relationship to the performance of radical neck dissection.     

Catecholamine contents and activities of catecholamine synthesizing and inactivating enzymes in the salivary glands of young growing rats

The catecholamine concentrations and activities of tyrosine hydroxylase, DOPA decarboxylase, dopamine β-hydroxylase, catechol 0-methyltransferase and monoamine oxidase in the submandibular and sublingual glands of developing rats ranging in age from 1 to 70 days were measured. The total concentration of catecholamines and the total activities of tyrosine hydroxylase and monoamine oxidase increased markedly up to 56 days and then remained at about the same levels. The total activities of dopamine β-hydroxylase increased steadily between 1 and 70 days of age. The total activity of DOPA decarboxylase increased rapidly to approximately 55-fold up to 21 days of age, thereafter decreasing markedly and at 70 days of age was only 2.6-fold higher than that at 1 day of age, probably because endogenous inhibitors are present in the submandibular gland of rats older than 42-days. The total activity of catechol 0-methyltransferase increased 38-fold up to 56 days of age, and thereafter decreased. Catecholamine concentrations and activities of the enzymes per unit weight reached maximal levels at the age of 14 or 21 days except for catechol 0-methyltransferase which reached maximal activity at 42 days of age. After 14 days, the catecholamine concentrations remained at almost the same level. The activity of dopamine β-hydroxylase and catechol 0-methyltransferase increased 2–3-fold reaching maxima at 21 and 28 days respectively. The monoamine oxidase activity remained at about the same level after birth.     

Rabbit calvarial wound healing by means of seeded Caprotite scaffolds

Autologous bone is the most successful bone-grafting material; however, limited supply and donor site morbidity are problematic. Synthetic bone substitutes are effective, but healing is slow and unpredictable. Osseous wound healing may be enhanced if bone substitutes are combined with autologous bone marrow cells. To test this hypothesis, we created 40 calvarial defects in 20 12-week-old New Zealand White rabbits, divided into four groups: (1) unrepaired controls, (2) autologous bone grafts, (3) unseeded Caprotite (a polymer-ceramic composite) grafts, and (4) Caprotite grafts seeded with autologous bone marrow stromal cells. CT scans were obtained at 0, 6, and 12 weeks post-operatively, and defects were harvested for histology. Defects repaired with autologous bone had significantly (p < 0.05) more bone than the other three groups, although seeded Caprotite defects showed different wound-healing sequelae. Results suggest that seeded Caprotite scaffolds did not significantly enhance osseous defect healing compared with controls.     

Das Landschwein als Modell für Ausbildung, wissenschaftliche Untersuchungen und Entwicklung neuer arthroskopischer Operationsmethoden am Kiefergelenk

Aim of the study

The aim of this study was to establish a reliable educational model for and a further refinement of arthroscopic surgery in the temporomandibular joint (TMJ).

Material and methods

As a first step, the lateral-medial (length) and anterior-posterior distances (width) of the mandibular head of nine pig cadavers (country breed) of about 30 (n=3), 60 (n=3) and 90 kg (n=3) body weight were measured and compared with findings in 12 adult human cadavers. The best points of access for the arthroscopic and lavage channels using the triangulation technique were determined. As determined by these findings, 15 arthroscopies were performed on eight pig TMJs under general anaesthetic. A control arthroscopy was performed after 2 weeks followed by another clinical follow-up at 4 weeks before the pigs were sacrificed.

Results

The TMJ of the pigs between 30 and 60 kg body weight was found to be highly comparable to the human TMJ. The best locations for puncturing the upper joint compartment of the TMJ in pigs were 5.0 cm and 6.1 cm anterior to the tragus on a line drawn along the lower margin of the zygoma. The only complication encountered was a subcutaneous infection treated successfully by antibiotics and incision.

Conclusions

In our opinion, a standard and easily reproducible model is necessary for further studies in arthroscopic TMJ-surgery. The country bred pig represents a good model for educational purposes and for studying further refinements of arthroscopic technique.      

Multidirectional distraction osteogenesis for Crouzon syndrome: technical note

This report describes multidirectional distraction osteogenesis in a patient with Crouzon syndrome. A RED system and a Hyrax expansion screw were used for lateral expansion of the maxilla. Advancement distraction osteogenesis and a Dyna Form were used for widening distraction osteogenesis of the mandible. The devices were fixed after a quadrangular osteotomy and a bimaxillary midline osteotomy.     

Isolation and characterization of aminopeptidase from Capnocytophaga granulosa ATCC 51502

There is evidence that enzymes from the genus Capnocytophaga play a role in dental calculus formation. Although most of the species in the genus produce aminopeptidases, there is a paucity of data on the purification and characterization of the enzyme, except in the case of Capnocytophaga gingivalis. The aim of this study was to purify aminopeptidase from culture supernatant of Capnocytophaga granulosa ATCC 51502, a new species of the genus. Purification was performed using ammonium sulfate fractionation and two chromatographic steps. The aminopeptidase was purified 158,433-fold with a yield of 12.0%. The enzyme appeared to be a trimer with a molecular mass of 270 kDa. The optimal pH of the aminopeptidase was 6.5 and its activity was completely inhibited by incubation at 50 degrees C for 10 min. The enzyme showed maximum specificity for basic amino acids (Arg and Lys) and also hydrolyzed noncharged amino acids (Met, Leu and Ala). Ca(2+), Zn(2+) and Fe(3+) activated the enzyme, while EDTA, Ag(+), Hg(+) and Cu(2+) inhibited it. These results suggest that aminopeptidase of C. granulosa is different from that of C. gingivalis but similar to aminopeptidase B.