University of Otago microbiology researcher Glenn Walker
reflects on his anti-dental plaque research, beside Harbour
Mouth Molars, a sculpture by artist Regan Gentry, at the
head of the Otago Harbour. Photo by Craig Baxter
University of Otago researcher Glenn Walker has
highlighted a new way of attacking dental pathogens that result
in $US20 billion a year in dental treatment bills in the United
Mr Walker (36) will graduate from the university with a PhD
in microbiology and immunology tomorrow.
His main supervisor is Otago University microbiologist Prof
John Tagg, a New Zealand pioneer of the concept of using
bacteriocin-like inhibitory substances (Blis), produced by
naturally occurring oral bacteria, to counter bacterial
pathogens in the human mouth and throat.
Mr Walker said some dental plaque was a ''glue-like gel''
that prevented the large Blis proteins from penetrating,
somewhat limiting their effectiveness in attacking pathogens
situated close to the tooth.
His research had investigated the possibility of launching a
two-phase attack on plaque, first by using a naturally
occurring enzyme, dextranase, to break into it.
Breaking up the plaque would then allow large Blis proteins
to attack the oral pathogens, particularly mutans
streptococci (MS) bacteria, that caused tooth decay.
There were promising early indications this approach could
''increase the killing efficacy of anti-MS bacteriocins'' in
''I feel very pleased that a lot of hard work paid off,'' he
said this week.
Theoretically, a probiotic product could be developed to
combine beneficial, naturally occurring bacteria that
generated the enzyme, and other organisms that produced the
pathogen-killing bacteriocin, to counter oral plaque.
''If a product went to market and people got benefit from it,
that would be quite amazing,'' Mr Walker said.
''Dental caries is the most prevalent infectious disease of
humans and can ultimately result in destruction of affected
teeth,'' he said.
''Recent studies indicate that there is a resurgence of
dental caries occurrence in both developing and developed
Prof Tagg said Mr Walker should be ''proud'' of his research,
which highlighted a promising new line of attack on dental