Remineralization of enamel subsurface lesions by xylitol chewing gum containing funoran and calcium hydrogenphosphate.

The aim of the present study was to determine the remineralization effects of xylitol chewing gum containing funoran and calcium hydrogenphosphate on enamel subsurface lesions in humans. The study was a double-blind, randomized, cross-over design, with 4 types of gum: (1) xylitol gum, (2) xylitol gum containing funoran and calcium hydrogenphosphate, (3) sugar gum, and (4) gum base as a control. Seven subjects were instructed to wear removable lingual appliances, with half-slab insets of human enamel containing demineralized subsurface lesions. They were told to chew gum for 20 minutes 4 times per day for 7 days. Upon completion of each treatment the enamel half-slabs were paired with their respective demineralized control half-slabs, embedded, sectioned, and subjected to microradiography and densitometric image analysis, for measurement of the level of remineralization. The mean area of remineralization (deltaZd-deltaZr) and mean percent remineralization (%R) in those chewing xylitol gum containing funoran and calcium hydrogenphosphate were significantly higher than the corresponding values for xylitol gum, sugar gum and gum base. Chewing xylitol gum containing funoran and calcium hydrogenphosphate has a significant effect on the remineralization of initial caries-like lesions of the teeth.

Plaque pH response to snack foods in children with different levels of mutans streptococci.

This study aimed to investigate the effects of some snack foods on plaque pH in children with different levels of mutans streptococci (MS). Six children, aged 9-12 years, with low (<10(4)) and 6 children, aged 10-12 years, with high (>106) numbers of MS/ml saliva participated in the study. Dental plaque pH changes, after the consumption of milk chocolate, sweet biscuit, instant noodle, sticky rice with banana and a 10% sucrose positive control were measured using pH-electrode. The measurements of plaque pH were made on forty-eight-hour accumulated plaque, at baseline to determine the resting pH of the fasted plaque and at time intervals of 2, 5, 10, 20 and 30 minutes after food consumption. The plaque pH curves, delta pH values and area under curve for pH 6.0 for each test food were determined. Plaque acidogenicity was more pronounced for the high-MS group at almost all test periods compared to the low-MS group with all test foods. The test foods were ranked according to maximum pH drop in about the same order in both groups as follows: 10% sucrose > milk chocolate > sweet biscuit > sticky rice with banana > instant noodle. The plaque pH also stayed below pH 6.00 for a longer period in the high-MS group with sweet biscuit, milk chocolate, and sticky rice with banana. Findings suggest that pH responses were more acidic in high-MS group than low-MS group.

Salivary mutans streptococci and lactobacilli after self arresting caries treatment.

Previous studies have shown that Self Arresting Caries Treatment (SACT) may be a useful technique to arrest active caries in Thai preschool children in remote areas. The objective of this study was to examine the effect of SACT on the levels of salivary mutans streptococci and lactobacilli in Thai children. Eighty-two subjects aged 4-6 years from primary school in a remote area of Thailand were recruited for this study. Each subject has at least two pairs of interproximal carious cavities between the first and second deciduous molars, and no history of severe pain. The subjects were divided into the control and SACT groups. The SACT technique was performed by removing food remnants and the surrounding overhang enamel of the carious cavity walls to enlarge the space between the carious cavities. The levels of mutans streptococci and lactobacilli in paraffin-stimulated whole saliva were determined at baseline, 2 and 4 months after treatment compared to those of the control group by the spatula method. The bacterial growth score was divided into three categories: 1 = 0-20 CFU, 2 = 21-100 CFU, and 3 > or = 100 CFU. At baseline, no differences in the mutans streptococci and lactobacilli scores were found between the SACT and control groups (p>0.05). Lower salivary lactobacilli levels were found in the SACT group on follow-up at 2 and 4 months (p<0.05), whereas the mutans streptococci level remained unchanged during these time periods. Our data confirms that the SACT technique can promote a self cleansing condition for interproximal lesions and can reduce the retentive sites in the oral cavity due to a reduction in salivary lactobacilli.

The effect of xylitol chewing gum on mutans streptococci in saliva and dental plaque.

Dental caries are one of the most common infectious diseases occurred in Thai children. The chewing of xylitol, sorbitol, and even sugar gum has been suggested to reduce caries rates. The aim of the present investigation was to evaluate the effect of xylitol chewing gum on mutans streptococci (MS) in saliva and dental plaque. Ninety-one children, aged 10-12 years, with more than 1 x 10(5) MS per milliliter of saliva were included in this study. They were divided into three groups balanced according to their MS counts at baseline: one control group (no supervised gum use), and two xylitol groups (supervised 55% and 100% xylitol gum use). Whole saliva and pooled plaque samples were obtained after 90 school days. When comparing the MS counts between the groups, those chewing 100% and 55% xylitol gum showed significant reductions (p < 0.025), but a dose response effect was not demonstrated. Chewing 100% xylitol gum caused significant reductions on salivary MS scores (p < 0.025) which was little different from the 55% xylitol group. The results suggest that the use of xylitol chewing gum can reduce the levels of MS in plaque and saliva.

Characters of a dean of the autonomous University.

Opinion about the appropriate characters of a dean of the autonomous university, regarding the academic level, administrative ability and method of selection was elicited in a survey among selected academic staff of Mahidol University during June 15-30, 1998. A questionnaire was designed and distributed to all administrators (n=302) of the University and to a random sample of 471 from 2,360 academic staff who did not have administrative position. A total response rate of 46.1 percent was achieved. Sixty-two percent of the responders were administrators and 80 percent of them were older than 40 years of age. Our study revealed that no sexual preference for a dean in 93.6 percent. The dean should be at least 40 years old (61%) but the one who retired, were not suitable (54%). Seventy-seven percent agreed that the dean’s profession should be the same kind as of officials of that faculty and a talent outsider is still unacceptable (58%). Previous experience in university administrative ability before being chosen. Sixty-five percent preferred to have equal ability in administration and academic achievement though 31 percent preferred the former to the latter. Academic level of associate preferable or higher with master degree or higher of relevant profession to the Faculty is preferred in 63 and 85 percents respectively. Publication in a peer reviewed international journal is required in 59 percent with emphasis on citation in international journal in 47 percents. Election by faculty staff is preferable to selection by a search committee and the selected candidate must be accepted by more than 50 percent of the faculty staff. All members of the search committee should have good reputation and accountability. The opinion about the academic level of the dean by administrators who had academic level of lecturer and assistant professor was different from other groups. The former voted the academic rank of the dean to be any ranks from lecturer while the latter preferred associate professor and professor to other lower ranks.