Meirin College

About: Meirin College is a education organization based out in Niigata, Japan. It is known for research contribution in the topics: Flexural strength & Tongue. The organization has 34 authors who have published 33 publications receiving 159 citations.

Anchorage effects of a palatal osseointegrated implant with different fixation: a finite element study

Abstract: The purpose of this study was to compare the anchorage effect of the osseointegrated implant with different fixation types using finite element analysis. Three fixation types were investigated. fixation type 1: implant neck in the oral-palatal cortical bone and implant tip in the cancellous bone; fixation type 2: implant neck in the oral-palatal cortical bone and implant tip in the nasal-palatal cortical bone; fixation type 3: implant neck in the oral-palatal cortical bone and implant tip projecting into the nasal cavity. Three finite element models were constructed. Each consisted of two maxillary second premolars, their associated periodontal ligament (PDL), alveolar bones, palatal bone, palatal implant, and a transpalatal arch. Another model without an implant was used to compare with the previous models. The horizontal force (mesial five N, palatal one N) was loaded at the buccal bracket of each second premolar. The stress was calculated in the PDL and implant surrounding bone. The result showed that the palatal implant could significantly reduce von Mises stress (maximum von Mises stress was reduced 30%) and evenly distribute stress in the PDL. The stress magnitude and distribution in the PDL was almost the same in the three implant models. These results suggest that different implant fixation types have almost the same anchorage effects.

NaF induces early differentiation of murine bone marrow cells along the granulocytic pathway but not the monocytic or preosteoclastic pathway in vitro.

Abstract: The stimulatory effects of sodium fluoride (NaF) on bone formation have been explained solely, by its activation of osteoblasts. However, whether and how NaF acts on the osteoclast linearge is poorly understood. We previously found that NaF differentiates HL-60 cells to granulocytic cells. To further test this action, we have employed here primary cultures of progenitor cells derived from murine bone marrow. NaF at subtoxic concentations (<0.5 mM) significantly up-regulated activities of several intracellular enzymes (lactate dehydrogenase, β-glucuronidase, acid phosphatase), cellular reduction of nitroblue tetrazolium, and nitric oxide (NO) production; which are all accepted as general differentiation markers. NaF (<0.5 mM) also up-regulated granulocyte-specific markers (chloroacetate esterase, cell surface antigens[Mac-1, Gr-1]) but not any of the monocyte-specific markers (nonspecific esterase, cell surface antigens [F4/80, MOMA-2]). Although other general differentiation markers (phagocytosis, adhesion, appearance, nuclear:cytoplasmic ratio) were not appreciably influenced by NaF, essentially in support of our prevous data from HL-60 cells, the present findings suggest that NaF induces early differentiation of bone marrow hemopoietic progenitor cells along the granulocytic pathway but not the monoicytic pathway that is linked to osteoclast formation. Therefore, in addition to its potent stimulatory effects on osteoblastic bone formation, NaF applied to patients with osteoporosis could be expected to indirectly reduce osteoclastic bone resorption.