Yet despite the inclination towards more favorable assessments, patients did not usually rank their pearly whites as being the best that they could be.

"They only gave themselves scores of six out 10," he noted. "This could mean that they are content, but realize that they do not compare with the 'perfect smiles' of Julia Roberts, Angelina Jolie, etcetera."

Fardal and co-author Jannike Jornung, a graduate student in the department of orthodontics in Sweden's Sahlgrenska Academy at Goteborg University, published their findings in the December issue of the Journal of the American Dental Association.

To gauge patient and dentist perceptions, the researchers first interviewed 78 patients at a general dental practice in a small rural Norwegian community during September of 2004.

The patients were between the ages of 22 and 84 and, at the time, none were seeking any kind of aesthetic dental care. Nearly two-thirds were women.

Written questionnaires were completed, in which patients assessed on a scale of one to 100 the shape of their lips; the appearance of the soft tissue (gingiva) surrounding their teeth; the shade, shape and alignment of their teeth; and the overall state of their smile.

Patients were also asked to indicate if they thought they had crooked teeth and/or receding gums.

No photographs or mirrors were provided, as patients were asked to grade themselves from memory.

In addition, all the men and women also ranked various facial features according to how important they believed they were to overall attractiveness. Features included hair and hairline, eyes and eyebrows, nose, skin, ears, lips, teeth, chin and the shape of the head.

Digital photos were then taken of the smiles of the first 40 patients, and both the attending dentist and Fardal independently arrived at aesthetic scores based on assessments of tooth shade, spacing, crowding, inflamed tissue and overall appearance.

At no time had Fardal been involved in the dental care of any of the patients.

The authors found that on a scale of 100, average patient satisfaction with the state of their smile came to just over 59 -- a figure that rose significantly among patients under the age of 50.

By contrast, the two dentists' assessments taken together registered at about 40 on the scale.

Specifically, patients were most satisfied with the state of their soft tissue (gingiva) when they smiled. They were least satisfied with the color of their teeth, which they generally described as being too dark.

Skin condition followed teeth and eyes as the most important features contributing to a person's facial attractiveness. Female patients said that teeth and hair were more important to them than did the men, while the men said head shape was more critical.

Fardal and Jernung suggested that dentists should remember that their opinion of the aesthetics of a patient's smile may not match that of the patient.

"Whether the 'perfect smile' exists is a different question," said Fardal. "The smile is made up of the teeth, gums, lips and jaws, and we as dentists use criteria and guidelines attempting to produce the 'perfect smile.' However, how many people actually fulfill these criteria is not known."

"Furthermore, the beauty is in the eye of the beholder," he added. "So there are a lot more smiles that are found to be attractive than just the 'media-created smile'. In addition, social and cultural differences exist, where different features are deemed attractive."

Dr. Edmond Hewlett, a consumer advisor to the American Dental Association, and an associate professor in UCLA's School of Dentistry in Los Angeles, agreed that dentists are trained to look for certain agreed-upon tooth proportions, symmetries, sizes, shapes and coloring when assessing a person's smile.

"I think there is a notion of what the components of an optimally attractive smile," he said. "There are certain parameters that are commonly utilized when a dentist looks at a smile. Then you take these very general parameters and apply them to every individual person with their unique features."

"It's certainly not a cookie-cutter situation, like a Julia Roberts template that we want to stick in everybody's mouth," he stressed. "But when you look at a beautiful smile you do see a lot of the same features -- either because the person is blessed or through orthodontic work -- which we all find appealing.

"Models, for example, consistently have central incisors which tend to be a little bit wider and longer than the other teeth in the front," Hewlett noted. "And yet when you look at two famous actresses -- Kirsten Dunst and Patricia Arquette -- both have a type of crookedness. The incisors are actually tilted back a little, and the canine teeth look more prominent like fangs. Yet both have commented in interviews that they are tired of people telling them to change their teeth. They're quite confident and comfortable."

"And that's the subjectivity of attractive teeth personified," he noted. "They're comfortable in their own skin, and they don't feel the need to conform to some culturally driven ideal of beauty. And that's something I think that dentists need to be sensitive to as well."

More information

For additional information on cosmetic dentistry, visit the American Dental Association.