The purpose of this investigation was to find the relationship between the occurrence of Candida species and mutans streptococci at 7 sites (saliva, tongue, mucosa, teeth, clasp, external, and mucosal denture surfaces) in the mouth of 97 elderly persons (males : 43, age : 76.4± 6.7 years; females : 54, age : 75.0 ± 6.6 years) . Among the subjects, there were complete denture wearers (n=20), partial denture wearers (n = 45), and non-denture wearers (n= 32) . Candida species were more significantly (p<0.001) predominant in complete and partial denture wearers (80% each) than in non-denture (18.8%) wearers. The presence of Candida was highest on the mucosal denture surfaces followed by clasp, tongue, and remaining teeth in that order. Positive correlations were significantly found between the CFU numbers of Candida species and mutans streptococci present on the external surfaces (p < 0.001), natural teeth (p<0.001), clasp (p<0.01), and saliva (p<0.05) . A negative correlation (r= -0.503 ; p<0.001) was found between the number of teeth and the CFU numbers of Candida species. Moreover, the CFU numbers of both groups of microorganisms also increased in 80-year-old and over persons. Candida species were most predominantly found in persons with poor oral and denture cleanliness.
The soft denture liner was applied to dentures for the edentulous patients with poor residual ridge and thin mucosa. It is useful for minimizing the soreness caused by the denture during mastication, however, its effect on masticatory functions has been rarely investigated. The purpose of this study was to determine the effect of a soft liner applied to complete dentures on masticatory functions. Five edentulous volunteers who were satisfied with their new complete dentures took part in this study. The lower dentures were lined with a soft liner. Comparison of occlusal force, masticatory performance, masseter muscular activity, and mandibular movement were made between new dentures and relined dentures. The results of applying soft materials to lower dentures obtained by comparison with complete dentures using hard acrylic resin bases were follows 1. occlusal forces were significantly larger (p<0.01) . 2. Masticatory performance in chewing peanuts increased slightly. The number of strokes and time for masticating a peanut decreased significantly (p<0.01) . 3. Masticatory muscles functioned more rhythmically and mandibular movements became smoother. 4. Integrated EMGs per stroke of all patients was similar.
The purpose of this study was to examine microbiological changes after periodontal initial therapy by DNA probe and polymerase chain reaction (PCR) assays in addition to clinical evaluation. Twenty-six periodontitis patients, 10 males and 16 females, were selected. All subjects were treated by scaling and root planing following oral hygiene instruction. Bacterial samples were collected with paper points from a total of 104 sites, 4 sites in each patient, at baseline and after initial therapy. DNA probe analysis was used to monitor Bacteroides forsythus and Porphyromonas gingivalis. PCR analysis was performed to identify the presence of Actinobacillus actinomycetemcomitans. The initial therapy resulted in significant clinical improvements as assessed by clinical parameters including pocket depth, attachment level and bleeding on probing. After the therapy, the detection frequency of B. forsythus and P. gingivalis was significantly reduced, but the detection frequency of A. actinomycetemcomitans did not significantly decreased. These results indicated that initial therapy can bring about elimination of B. forsythus and P. gingivalis by means of conventional techniques, but not of A. actinomycetemcomitans. When complete elimination of these microorganisms was obtained, significant clinical improvement was found. Monitoring the changes of three bacteria may provide a more effective modality.
In the 1950 s, a new method of using magnets for the retainers of removable partial dentures (RPDs) was developed. It utilized magnetic attractive force instead of mechanical friction. However, the magnets used in those days were Alnico, Ferrite and/or Pt-Cobalt magnets and their retentive force was not strong enough to stabilize the dentures. Therefore, they gradually went out of use. In the middle of the 1970 s, Samarium Cobalt magnets, which have strong magnetic characteristics, were developed and introduced into dental field. In 1976, Sasaki first applied the samarium cobalt magnets to the retainers of PPDs. While in 1981, Mizutani, et al. first used wellfitted ferromagnetic alloy and the magnet for the purpose of stabilizing the RPD. Since then, many researchers have developed devices such as the magnetic retainer and the closed field magnetic attachment placed on the market in 1992. Now, as for the popular retainer of RPD, one can easily use a smaller yet stronger magnetic attachment which uses Neodium rather than Samarium Cobalt magnet.