Peripheral giant cell granulomas are common proliferative lesions of the oral cavity with a predilection for females. In this study, the presence of estrogen and progesterone receptors in 26 peripheral giant cell granuloma cases were studied utilizing the immunoperoxidase technique. In fourteen cases, estrogen receptor positivity was found in stromal cells. In ten of these, osteoclast-type giant cells also exhibited estrogen receptor immunostaining. Progesterone receptor expression was not detected. It was concluded that the cells forming peripheral giant cell granuloma are potential targets for estrogens and that these lesions might be conditioned by sex hormones.
Magnetic retention devices based on cobalt/samarium alloy are new to dentistry, whereas precision attachments have been used for many years. In this study, the retentive forces of two magnetic systems were compared with two different precision attachment units. The retentive forces were evaluated with an Instron testing machine with a cross-head speed of 0.5 mm/min. Eight samples were used for each of the four attachments for a total of 32 samples. The attachments were embedded in an acrylic block and tested for initial retention and retention after 300 cycles. The retentive forces of the precision attachments were greater than the magnetic attachments for the initial retention. However, as more cycles were completed, the retentive force decreased in the precision attachments and increased in the magnetic attachments. The results were statistically significant among the four attachment systems (p = 0.0117).
Large quantities of Prevotella nigrescens (intermedia) ATCC 25261 (P. nigrescens) cells adhere to hydroxyapatite (HA) treated with citrate, but do not adhere experimental pellicle prepared from human whole saliva. To determine the nature of the citrate responsible for promoting P. nigrescens cell adhesion, the duration and frequency of citrate treatment of HA and the inhibitory effect of other carboxylates were tested. The citrate rapidly adhered to HA beads in less than 15 min. With a lower concentration (0.4 mM) of citrate, four treatments of HA were required to promote the maximum adherence to P. nigrescens cells. Citrate-enhanced P. nigrescens cell adherence to HA beads was also inhibited in the presence of cis-aconitate, oxaloacetate and oxalsuccinate. It was also found that P. nigrescens cells heated to 65°C or higher for 5 min could no longer become attached to citrate-treated HA. These data suggest that citrate is one of the essential factors responsible for P. nigrescens cell attachment to apatitic surfaces, and that P. nigrescens' adhesion to citrate is extremely heat-sensitive.
Self-setting cements, αD-Cement and αDT-Cement, were prepared. They consisted of only the calcium phosphates α-TCP, TTCP and DCPA. These cements reacted and hardened in a moist environment at 37°C. The powder X-ray diffraction patterns were taken to examine the conversion of their reactions as a function of time. The cements reacted and produced hydroxyapatite. The optimum powder/liquid ratio of aD-Cement was 2.0 and that of αDT-Cement was 1.8. The initial setting time of αD-Cement was 87.5 m and that of aDT-Cement was 107.5 m. The component and the product of these cements are calcium phosphates which are the putative minerals in teeth and bones. Therefore, these cements are useful for oral surgery as bone-filling materials
This study used biochemical and light and electron microscopic immunohistochemical methods to localize and characterize large hyaluronate-binding proteoglycans in the developing mandible of fetal rats at embryonic day 15 (Day 15) to Day 18 using a monoclonal antibody (MAb) 5D5. This antibody is derived from bovine sclera and specifically recognizes the core protein of large proteoglycan such as versican, neurocan and brevican, but not that of aggrecan. At the light microscopic level, MAb 5D5 moderately stained the extracellular matrices among osteoblasts at the centers of ossification in Day 15 mandible specimens. Weaker staining was observed in osteoblasts, whereas Meckel's cartilage lacked staining. Ultrastructural immunocytochemistry showed the presence of immunogold particles over unmineralized matrices among osteoblasts and their intracellular organelles. In Day 16 to 18 specimens, bone nodules were recognized in LR gold sections before immunostaining, but, after immunostaining, consistently appeared devoid of mineral crystals and were seen as a demineralized structure that had an electron dense periphery within which fine filamentous and granular material were present. The appearance of these structures was created by the demineralization of thin sections on grids during immunostaining. Specific immunogold staining was clearly seen over the demineralized structures corresponding to bone nodules. The majority of immunogold particles tended to localize inside of the structures. Bone proteins were extracted from fresh, Day 18 specimens with a three-step technique : 4 M guanidine HC1 (GdnCl, G1-extract), aqueous EDTA without GdnCl (E-extract), followed by GdnCl. Western blot analysis of SDS-polyacrylamide gel electrophoresis after chondroitinase ABC digestion, showed that G1-extract gave a 5D5 reactive band greater than 400 kDa, whereas E-extract produced two major reactive populations of small molecular size with core proteins approximately 63 and 74 kDa. These results indicate that the large proteoglycan having smaller molecular weight is preferentiallylocalized to bone nodules and may correlate with bone matrix mineralization.
Kinematic imaging of the temporomandibular joint (TMJ) was applied for diagnosis of TMJ disorders using an ultrasonic diagnostic imaging system. Patients with a normal TMJ (male, 24 y 1 mon) and a symptomatic TMJ (female, 20 y 2 mon) were selected for imaging. The transducer must be placed in a specific location in order to propagate ultrasound through soft tissue because it is difficult for ultrasound to penetrate bone such as the condyle and the eminence. Therefore the ultrasonic images were not taken in sagittal cross-section, as is the case with magnetic resonance images. The ultrasonic diagnostic imaging system showed a transverse cross-section and no hard tissue images. It was difficult to become accustomed to these images, thus making it difficult to find differences between the normal TMJ and the symptomatic TMJ on the basis of static ultrasonic images alone. However a difference between the kinematic images of the normal and symptomatic TMJ was observed during jaw opening. Irregularity in the striated pattern of the soft tissue surrounding the condyle was observed in the image of the symptomatic TMJ. In order to make a precise diagnosis using ultrasonic imaging, it may be useful to understand the kinematics of the soft tissue surrounding the TMJ during jaw opening and closing.