A radiographical classification of Stafne's bone cavity

So-called Stafne's bone cavity of the mandible were detected by panoramic radiography in 24 patients seen at the Second Department of Oral and Maxillofacial Surgery, Meikai University Hospital, and five associated hospitals. Unilateral and asymptomatic, all lesions were situated near the angle of the mandible, except for the one case that involved the anterior portion of the mandible. The mean age of the patients was 53 years with a range of 31 to 78 years, and included 22 men and 2 women. In this report, radiographic interpretation of the lesion was done, and a radiographic classification was made as follows:

1. (Indentation type): The inferior border of the mandible is involved.
2. (Medium type): The lesion is situated above the inferior border of the mandible but below the mandibular canal.
3. (Deviation type): Deviation of the mandibular canal is suspected.
4. (Anterior type): The radiolucency is located in the anterior portion of the mandible.

     

Analysis of brain activity during clenching by fMRI

It has been considered difficult to obtain satisfactory functional magnetic resonance images (fMRI) during jaw movements because the head motion during jaw movements makes artefacts on the images. To avoid these artefacts, we chose clenching task and larger pixels to allow some head motion of the subjects. Further the study discarded all data from subjects whom the head was evaluated to move more than 0.3 mm. The study examined 10 healthy right-handed volunteers with echo-planar magnetic resonance (MR) imaging and functional MR signal intensity changes could be obtained in all subjects. However, in the analysis of each pixel of individuals, three different types of pixels were established. It was determined that the pixels that synchronized positively with the task on/off and where signal intensity increase was below 10% expressed the real brain activity. Pixels showing the real brain activity were found in the sensory, motor and pre-motor cortexes in both hemispheres in all subjects, and also in the insula region of two subjects. No pixels were found in the striatum and supplementary motor areas. From the above careful consideration and individual analysis of each pixel, it was concluded that brain activity during the clenching task could be obtained by fMRI.     

Ultrastructure of initial calcification on exposed human pulp applied with autogenous dentin fragments

Initial calcification in human dental pulp has been studied with electron microscopy in 20 human teeth over a period of 21 days following pulp exposure and capping with autogenous dentin fragments. Five days after operation, dentin fragments were surrounded by degeneration cells and inflammatory cells. Occasionally a macrophage that had phagocytosed a dentin fragments was observed. Fourteen days after operation, osmiophilic needle-like crystalline structures were found in spherical bodies in the collagen fibrils or on the dentin surface. Ca and P were detected in these needle-like crystalline structures by energy dispersive X-ray analysis. They tended to increase in size and to fuse together to form mineralizing globules with the passage of time. Initial calcification around the dentin fragments developed various patterns, including spherical bodies in the collagen fibrils and direct apposition of needle-like crystals on the dentin fragments.     

Differential expression of CR3, FcɛRll and FcγRlll on Polymorphonuclear leukocytes in gingival crevicular fluid

Polymorphonuclear leukocytes (PMNLs) are the most numerous cell population among the cellular infiltrates in gingival crevicular fluid (GCF) and play important roles in the host-defensive system in the gingival crevices. We determined the percentage of neutrophils, cosinophils and basophils in total PMNLs by light microscopic observation using Randolph-methylene blue staining, then assessed flow cytometric differences in the expression of CR3, FcγRIII, FcɛRII. LFA-1α, and LFA-Iβ on PMNL in GCF and peripheral blood (PB) from 21 patients with adult periodontius (AP) and 13 healthy donors. Percentages of basophils and eosinophils were higher in GCF than in PB. In both AP patients and healthy subjects, expression of CR3 and FcɛRll was higher while FeγRIII was lower in GCF than in PB. The statistical analysis showed that the expressions of FcγRIII and FcɛRII on GCF PMNLs were lower in AP patients than in healthy subjects. Expressions of LFA-1α and β on GCF were similar to those on PB PMNLs. PB PMNLs stimulated in vitro with Porphyromonas gingivalts culture supernatant and fMLP displayed an expression pattern of CR3, FcγRIII and FcɛRII on GCF PMNLs. However, C5a and IL-I failed to induce changes in FcγRIII and FcɛRII. The results indicate that GCF neutrophils are activated, present enhanced adhesion and a decreased IgG-binding ability which would reflect that they are at the terminal stage of activation, and that GCF contains a larger eosinophil fraction than in PB. Moreover, these GCF eosinophils appear to be activated.     

Influence of the chemical structure of functional monomers on their adhesive performance

Functional monomers in adhesive systems can improve bonding by enhancing wetting and demineralization, and by chemical bonding to calcium. This study tested the hypothesis that small changes in the chemical structure of functional monomers may improve their bonding effectiveness. Three experimental phosphonate monomers (HAEPA, EAEPA, and MAEPA), with slightly different chemical structures, and 10-MDP (control) were evaluated. Adhesive performance was determined in terms of microtensile bond strength of 4 cements that differed only for the functional monomer. Based on the Adhesion-Decalcification concept, the chemical bonding potential was assessed by atomic absorption spectrophotometry of the dissolution rate of the calcium salt of the functional monomers. High bond strength of the adhesive cement corresponded to low dissolution rate of the calcium salt of the respective functional monomer. The latter is according to the Adhesion-Decalcification concept, suggestive of a high chemical bonding capacity. We conclude that the adhesive performance of an adhesive material depends on the chemical structure of the functional monomer.