Meirin College

About: Meirin College is a(n) education organization based out in Niigata, Japan. It is known for research contribution in the topic(s): Flexural strength & Tongue. The organization has 34 authors who have published 33 publication(s) receiving 159 citation(s).

Predicting the pharyngeal airway space after mandibular setback surgery.

Abstract: Purpose The purpose of this study is to propose a mathematical model to predict the change in pharyngeal airway space (PAS) associated with mandibular setback surgery. Patients and Methods Twenty-three female adults, who were diagnosed as having skeletal Class III deformity, underwent mandibular setback surgery by bilateral sagittal split ramus osteotomy (BSSO) and orthodontic multibracket treatment. The subjects were assessed within 6 months before operation (T1) and 1 to 1.5 years after mandibular setback surgery (T2). The PAS change in the level of the base of the tongue was predicted. Results The equation is: PAS narrowing = 0.386 − 0.541 ANB (T1 − T2) + 0.253 Co-Gn (T1 − T2) − 0.098 SN-GoGn (T1 − T2), where ANB is the angle formed by the planes nasion-point A and nasion-point B, Co is condylion, Go is gonion, and Gn is gnathion. The PAS change can be predicted by the mandibular changes after setback surgery 66.2% with the regression equation using the change of the ANB angle, the total mandibular length (Co-Gn) and the mandibular plane (SN-GoGn), where SN is sella-nasion. Conclusions The equation can be used to predict the change of pharyngeal airway space after mandibular setback surgery. In patients who have other risk factors, such as obesity, short neck, macroglossia, large uvula, and excessive soft tissue around the nasopharyngeal region, a mandibular setback surgery could possibly predispose to the development of sleep apnea syndrome.

Ten-year longitudinal study on the state of dentition and subjective masticatory ability in community-dwelling elderly people.

Abstract: Purpose The aim of this study was to reveal whether the differences in further loss of teeth and occlusal supports, and change in masticatory ability depend on the status of dentition at the age of 70 in community-dwelling elderly people. Methods A 10-year longitudinal survey was carried out on 349 (176 females and 173 males) elderly subjects. The subjects to be analyzed were classified into four groups in accordance with the classifications of Miyachi's Triangular Classification. Zone A: subjects with ten or more occlusal supports. Zone B: those with nine to five occlusal supports. Zone D: those with four or fewer occlusal supports and 11 or more remaining teeth. Zone C: those with ten or fewer remaining teeth. The numbers of remaining teeth and occlusal supports were recorded in both examinations. Questionnaires regarding their food intake status were given to subjects. Results Subjects in Zone B had greater numbers of teeth loss than those in Zones A and C. Subjects in Zone B and D lost greater numbers of occlusal supports than subjects in Zones A and C. The number of food items that could be chewed had significantly decreased in subjects who remained in Zone A and those who changed from Zone B to Zones D and C. Conclusions It was shown that various states of dentition classified by Miyachi's Triangular Classification at the age of 70 resulted in different numbers of remaining teeth and occlusal supports and changes in masticatory ability 10 years later in community-dwelling elderly people.

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.