Biomedical subjects

M Kawaguchi

Publications and source records attributed to M Kawaguchi.

418 records · Page 24Linked to original sources

PubMedDate not supplied

Flexural strength at the proportional limit of a denture base material relined with four different denture reline materials.

This study evaluated the resistance to plastic deformation under a flexural load (PLf) of a denture base material relined with four different types of denture reline materials. A heat-processed poly(methyl methacrylate) denture base was relined with varying thicknesses of denture reline materials and subjected to a flexural load. The flexural load at the proportional limit (PLf) was recorded. The PLf of the bulk denture base and denture reline materials were also measured for comparison. All relined denture bases showed significantly lower PLf than the bulk denture base. Generally, the PLf of the reline-denture base composite progressively decreased with an increasing proportional thickness of the reline material.

Analysis of Variance↗

PubMedDate not supplied

Ethnic or environmental differences in disparate geographic regions may influence the histology of flat colorectal neoplasias.

Histologic sections of endoscopically flat colorectal polyps removed in Tokyo and Stockholm were reviewed. A total of 178 flat colorectal neoplasias (88 from the Tokyo Medical College Hospital, Tokyo and 90 from the Karolinska Hospital, Stockholm) were classified following strict histologic criteria by two different pathologists (one Swedish and the other Japanese). The number of polyps with high grade dysplasia, with intramucosal carcinoma and with invasive carcinoma were significantly higher (p < 0.001) in Tokyo (61.4% or 54/88) than in Stockholm (15.0% or 14/90). The present results suggest that flat colorectal neoplasic polyps may be histologically more "severe" and more "aggressive" in Japanese than in Swedish patients. The possibility that more "advanced" lesions had been inadvertently removed in Tokyo was discounted as Japanese endoscopists were also instrumental in excising many of the flat colorectal polyps in Stockholm. Ethnic and/or environmental differences seem to play a crucial role in the evolution of flat colorectal neoplasic polyps from LGD and HGD, to intramucosal and to invasive carcinoma.

Adult↗

PubMedDate not supplied

Effect of water sorption on the resistance to plastic deformation of a denture base material relined with four different denture reline materials.

PURPOSE: The effect of water sorption on the flexural strength at the proportional limit (FSp) of a denture base material relined with four different denture reline materials was studied. MATERIALS AND METHODS: Denture base specimens were relined either after 24 hours or 30 days of water immersion. The relined specimens were tested after another period of 24 hours or 30 days of water immersion. RESULTS: Relined denture specimens generally exhibited lower FSp with an increase in water immersion time and an increase in the thickness of the reline material. CONCLUSIONS: The plasticizing effect of absorbed water molecules explains the general decrease in FSp of immersed relined specimens. The absence of a significant effect that water immersion had on some relined specimens under certain immersion conditions was explained by water sorption into the denture base achieving an equilibrium after a period of water immersion, and the resistance of some reline materials to the effect of water immersion.

Analysis of Variance↗

PubMedDate not supplied

The flexural strengths of denture base acrylic resins after relining with a visible-light-activated material.

PURPOSE: Previous studies disclosed the ability of a light-activated denture reline material to strengthen a particular denture base material. The present study investigated the ability of the reline material to strengthen denture base materials processed by other means. MATERIALS AND METHODS: Four denture base materials were tested for flexural strength at proportional limit (FSpl) with or without being relined. RESULTS: The reline material maintained the FSpl of the microwave-processed and the autopolymerizing denture base materials. It increased the FSpl of the heat-processed and the light-activated denture base materials. CONCLUSION: the light-cured reline material increased the flexural strengths of the heat-processed and the light-activated denture base materials and maintained those of the microwave-processed and the autopolymerizing denture base materials.

Acrylic Resins↗