Changes of Streptococcus mutans concentration of plaque during fixed appliance treatment / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the dynamic changes of Streptococcus mutans concentration of plaque during fixed appliance treatment and the effects of two materials of ligation on Streptococcus mutans concentration.</p><p><b>METHODS</b>Twenty-eight patients undergoing fixed appliance treatment were observed. Ligature wire and elastomeric rings were applied on one side of arches, stochastically. The dynamic changes on the quantity and percentage of Streptococcus mutans were observed before and after fixed appliance bonding.</p><p><b>RESULTS</b>Statistically significant increase of the quantity and percentage of Streptococcus mutans was found after fixed appliance bonding, and the percentage of Streptococcus mutans in the plaque around the brackets ligated with elastomeric rings was more than that of ligature wire at the beginning of fixed appliance bonding, statistically.</p><p><b>CONCLUSIONS</b>The finding suggested that the caries-associated capability of the plaque increased after bonding and there was greater caries-associated capability of the plague on the teeth when elastomeric rings was used than that of the plague when ligature wire was used at treatment beginning. The ligature wire is recommended in the fixed appliance treatment.</p>

Effect of chewing sugar-free gum after sucrose challenge on dental plaque pH in situ / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To evaluate the effect of chewing sugar-free gum after sucrose challenge on dental plaque pH in situ.</p><p><b>METHODS</b>16 healthy volunteers aged 23 - 32 years were screened as subjects. The pH of 48-hour dental plaque was measured using a Beetrode pH microelectrode when subjects chewed Extra sugar-free gum after sucrose challenge.</p><p><b>RESULTS</b>Dental plaque pH maintained at resting plaque pH when immediately chewed sugar-free gum after sucrose challenge. Chewing sugar-free gum at 5 min after sucrose challenge, dental plaque pH was raised from 5.59 (measured at 5 min after sucrose challenge) to 6.98 (measured at 10 min after sucrose challenge).</p><p><b>CONCLUSIONS</b>Chewing sugar-free gum after sucrose challenge can neutralize organic acid produced by bacteria in dental plaque and rapidly rise plaque pH.</p>