Bisphosphonate and the Eruption of Developing Teeth: Its Effects and Mechanism / 체질인류학회지

Bisphosphonates have similar chemical structures to endogenous inorganic pyrophosphate which inhibits mineral deposition in biological tissues. Even though their clinical applications have been attempted, their molecular mechanism and cellular effects on dental hard tissue development remain to be elucidated. The present study was performed to investigate their effects on the development of the tooth and their mode of action. Alendronate, a synthetic derivative of bisphosphonates was subcutaneously daily injected in postnatal day 1 Sprague Dawley rats for successive 10 days. Animals were sacrificed at 3, 12 and 40 days after the final administration and light microscopy, RT-PCR and TUNEL were used for the analyses. Alendronate inhibited the teeth development and retarded their eruption. In the alendronate group, the mandibular first and second molars were under-developed, compared with those in the control group at day 3. Ameloblasts in the mandibular 1st molar were discontinuous in several parts. The development of the mandibular 2nd molar was deterred by the woven bone growing into the dental papilla. The third molar tooth germ did not appear. The TUNEL positive cells were rarely seen in the normally developing hard tissue cells. But in the alendronate group, the positive cells appeared frequently in layers of ameloblasts. Furthermore, the expression of alkaline phosphatase mRNA was downregulated in the alendronate group, suggesting that osteoblastic activity was decreased. These results suggested that bisphosphonates may act on dental hard tissue cells, preventing tooth development and eruption.

Several Methods Of Fabrications Of Inner Crown And Outer Crown In Construction Of Konus Denture / 대한치과보철학회지

The purpose of this article is the consolidation of several methods in fabrication of Konus denture.It is different Konus denture from traditional Clasped removable partial denture in the procedures of construction.There are multiple procedures of fabrications of inner and outer crowns in the construction of Konus denture.It is important to fabricate the inner crown,the outer crown and the denture framework in construction of Konus denture.Each procedure should be performed exactly.However,there are many procedures in fabrications of them,and thus,the operator and technician bear trial and error.This article consolidate the multiple methods of fabrications of components of Konus denture.The first method is completion of inner crown,outer crown and denture after one impression taking.The second method is the procedures of cementation of inner crown,impression taking of edentulous area,and completion of outer crown and denture.The third method is the procedures of pick up impression taking of inner crown and completion of outer crown and denture on the inner crown of working cast.Each method is acceptable,but operator and technician should be accustomed with their own systemic procedures and minimize the errors in the construction of denture.

Residual Mercury in Soy-Bean Sprouts by Steps of Cooking / 예방의학회지

This study was carried out in order to estimate the residual amount of mercury in soy-bean sprouts in each steps of cooking. Samples were taken at markets and also cultured at home without applying the mercury containing pesticides as control. Mercury was determined by dithizone method. It was disclosed that soy-bean sprouts purchased at markets contained 1.32+/-0.274 ppm, 13 times as high as the maximal allowable concentration of mercury in food recommended by Ministry of Health and Social Affairs. Mercury contents, however, dropped off steadily by steps of cooking: rinsed with distilled water and boiled in distilled water showing concentrations of 0.11+/-0.025 ppm in boiled sprouts and 0.03+/-0.022 ppm in sprout-soup. These values were not statistically different from those in control samples, and not exceeded the maximal allowabled levels of mercury in food. It can be concluded that the use of mercury containing pesticides in the cultivation of soy-bean sprouts is not so serious problem as it has been suspected in respect of food contamination, but careful attention must be paid to indiscriminate use of mercury containing pesticides as they may contaminate air, water and soil and secondarily bring harm to human health through food chains.