The recently published study looked at 1037 participants aged between 15 and 32, in the long-running Dunedin Multidisciplinary Health and Development Study, of whom about a quarter were "dentally anxious".
People were dentally anxious if they were so frightened at the prospect of visiting a dentist, or having dental procedures, that they avoided the dentist altogether until the problem became so serious that treatment could no longer be avoided.
Prof Murray Thomson, from the university's department of oral sciences, said researchers found people with dental anxiety "tended to be the glass-half-empty personality type people" who, as a rule, would be anxious about other things, such as heights.
Some people were anxious due to bad dental experiences in the past, but usually they had become more anxious through a "vicious cycle" of avoiding the dentist to the point their dental condition became much worse and they required more unpleasant treatment options, such as lancing an abscess, root canal treatment or a tooth extraction.
"As a consequence, people who are dentally anxious end up with more tooth decay and more missing teeth than those who are not."
This was reflected in tooth decay statistics, which showed that dentally anxious people had double the number of decayed, missing or filled tooth surfaces by the age of 32, compared with non-anxious people.
A very small group of those studied had grown out of their dental anxiety.
Dentally anxious people tended to be more nervous, while non-dentally anxious people tended to have more robust personalities and were more able to cope with what life threw at them, Prof Thomson said.
The study had implications for both the dentistry profession and the public.
It gave the profession a good understanding of what made people dentally anxious and showed them to be mindful that some people could grow out of it.
For the public, it was useful to know that if people avoided dental care, they would be worse off in the end.
