the compounds of the present invention are linear and branched dextrans having a plurality of their glucose units modified at the 3 - position ring carbon with groups selected from the class consisting of keto , amino , halo , benzyl , alkyl , sulfonyl , carboxyl and hydrogen . the modified dextrans reduce and / or modify activity of glucosyltransferase enzymes which are produced by oral strains of streptococcus mutans bacteria . gtf enzymes mediate oral biosynthesis of plaque - forming glucose polymers from ingested sucrose . therefore , the dextrans of the present invention , which reduce and / or modify activity of gtf enzymes , are useful in reducing the formation of dental plaque . the present invention is further directed to a dental health method comprising the step of contacting the oral cavity with linear or branched dextran compounds having a plurality of their glucose units modified at the 3 - position carbon with a group such as keto , amino , halo , benzyl , alkyl , sulfonyl , carboxyl or hydrogen .