Text I. Eating habits - the rules or prejudices?

Caregivers should beware that young children who skip breakfast increase their chances of experiencing tooth decay, according to a study in this month's Journal of the American Dental Association.

Using data from the third National Health and Nutrition Examination Survey, conducted by the Centers for Disease Control and Prevention, the authors investigated the relationship between healthful eating practices (such as breast-feeding, eating breakfast and consuming five servings of fruits and vegetables a day) and dental caries in the primary teeth among children two to five years old.

In their analysis of more than 4,000 preschoolers, the authors found that poor eating practices (not eating breakfast and eating fewer than five servings of fruits and vegetables a day) were associated with caries in primary teeth among children. “Omitting breakfast was found to be associated with overall caries (tooth decay) experience and untreated decay in the primary dentition in children aged two through five years,” the authors wrote. “Our findings support the notion that healthful eating practices among preschoolers would contribute to further reduction in caries.”

Dental cavities among teenagers and young adults are not linked to soft drink consumption, Virginia Tech researchers reported to the annual meeting of the American College of Nutrition.

The findings of Rich Forshee and Maureen Storey, research faculty members with Virginia Tech’s Center for Food and Nutrition Policy, are based on an analysis of a large, nationally representative nutrition and health survey conducted by the federal government.

Forshee said the data show that regular consumption of carbonated soft drinks is not associated with dental cavities among adolescents, young adults, or older adults. There was, however, a positive association between soft drink consumption and dental cavities among adults in the 25-to-40 age group. He also said they found a modest association between socioeconomic status and cavities in those 17 to 40 years of age. Respondents to the survey who had more income and more education had slightly fewer cavities than those with less income and less education.

Among those over 40, the study found that African-Americans, Mexican-Americans, and respondents of "other races" have fewer dental cavities than do Caucasians. Mexican-Americans in the 25-to-40 age group also reported fewer cavities than Caucasians. Females had four to five more dental cavities on average than males.

Text II. A bibliographical survey of bruxism

Interdisciplinary Studies Program, Wayne State University, MI 48202, USA, 2001

What is bruxism?

The word bruxism is taken from the Greek word brychein -gnashing of teeth. No standard terminology exists, so we must try to clarify the confusion that still surrounds this subject. Bruxismcanperhaps be defined as the involuntary, unconscious, and excessive grinding or clenching of teeth. When it occurs during sleep, it may be best referred to as sleep bruxism. A few people, on the other hand, brux while they are awake, in which case the condition may be referred to as wakeful bruxism. The above terms are preferable to the widely-used nocturnal and diurnal bruxism, for the simple reason that one may engage in sleep bruxism during the day and in wakeful bruxism during the night.

All forms of bruxism entail forceful contact between the biting surfaces of the upper and lower teeth. Clenching involves silent, sustained, forceful tooth contact unaccompanied by mandibular movements. We should perhaps talk about bruxism only when the habit is persistent, frequent, long, or intense enough to damage the teeth and to lead to other complications. One's grinding or clenching of teeth fall under the rubric of bruxism only when they have already affected, or are expected to affect, one's well being.

Incidence of bruxism

No hard and fast figures on the frequency of bruxism are available. Most people unconsciously grind or clench their teeth now and then, so the key in the diagnosis of bruxism is not the presence or absence of the habit, but its frequency, destructiveness, social discomfort, or physical symptoms. Moreover, over 80% of all bruxers may be unaware of the habit, or ashamed of it, so they may dismiss evidence that they do in fact engage in self-destructive behavior. Also, it may take years for the first visible signs of worn teeth to appear; yet, often it is these signs that lead to a diagnosis of past or present bruxism. For these reasons, estimates of the prevalence of bruxism range from 5% to 100%. For the U.S. population, current estimates often settle on the 5-20% range. Regardless of the exact number, the figures are disturbing. At the very least, one out of twenty people brux. Inarguably, then, bruxism is a widespread behavioral pattern that adversely affects a significant fraction of the world's people.

Etiology of bruxism

The etiology of bruxism is controversial and uncertain. Putative causes include stress, personality types, allergies, nutritional deficiencies, malocclusion, dental manipulations, introduction of foreign substances into the mouth, central nervous system malfunction, drugs, deficient oral proprioception, and genetic factors.