The softer touch

Jan. 1, 1996
Hygienists can spot excessive toothbrush abrasion to circumvent future problems. So which patients should we be watching? Surprisingly, the `best` patients may be the ones who are brushing Rambo-style several times a day.

Hygienists can spot excessive toothbrush abrasion to circumvent future problems. So which patients should we be watching? Surprisingly, the `best` patients may be the ones who are brushing Rambo-style several times a day.

Eric L. Spieler, DMD

Excessive brushing force is the major cause of dental abrasion. A recent study compared the oral hygiene habits of abraders and non-abraders, and several common risks for causes of dental abrasion were identified, including excessive brushing.

A patient survey conducted during an office visit can diagnose inappropriate hygiene before the onset and development of abrasion and related symptoms. This diagnostic tool, used in conjunction with a tailored home-care program, can be a valuable deterrent to toothbrush abrasion before it occurs in children and young adults.

Toothbrush abrasion effects 85 to 90 percent of the dentally aware population. Over a lifetime, the consequences of abrasion have a profound effect on patient comfort and tooth morbidity. Abrasion typically causes continuous and irreversible damage to the teeth and gums. The damage can include gingival recession, dentin hypersensitivity, bone loss, elongated teeth, and cervical notching. Among teenagers, the prevalence of toothbrush abrasion has been described as "alarming," affecting up to 62 percent and 74 percent in two separate studies.

Given the epidemic proportions of this problem, early diagnosis and prevention are essential.

Brushing too hard

Several studies conclude that the underlying causes for toothbrush abrasion are not bristle hardness or toothpaste abrasiveness as once thought. This early suspicion may explain the introduction of dozens of softer, end-rounded bristles and less abrasive toothpastes during the past 40 years. However, these products have not lowered the incidence of toothbrush abrasion.

Excessive brushing force and poor technique are the more likely culprits. Since a 1941 study, the incidence of abrasion has remained unchanged. Manufacturers have developed better toothbrushes and pastes. The prevalence of abrasion persists because we have failed to address the real cause of the problem - excessive force.

To change abusive brushing behavior, we, of course, can teach patients what "appropriate force" means. But this can be difficult. Hygienists often see their patients only once or twice a year. In this limited time, we try to help patients modify a bad habit or to offer feedback on their progress.

Home-care aids can reinforce training beyond the dental office. One new manual toothbrush, for example, has a built-in sensor in the brush`s handle. The sensor monitors each stroke of the bristles and teaches patients the "feeling" of proper brushing force by triggering a warning light when too much pressure is applied. If the proper brushing force is used, the bristles will barely splay, allowing the brush to last approximately nine to 12 months.

Spotting the `abrader`

Hygienists can also determine which patients are at the greatest risk for abrasion damage before symptoms occur. A recent behavioral survey reveals characteristics that are common among patients who later develop abrasion-related problems. These characteristics can be useful in diagnosing overzealous brushing early enough to intervene and prevent damage.

In the study, 165 patients from two independent dental practices were randomly selected. The behavioral survey included nine questions about oral hygiene habits - frequency of brushing and flossing, bristle stiffness, knowledge about the risks of abrasion, etc.

Before completing the survey, each patient was classified as either an abrader or a non-abrader. Patients assigned to the abrader category had clinical manifestations of notched teeth consistent with abrasion but not abfractions or erosion, and/or gingival recession with no interproximal bone loss. Patients without these characteristics were categorized as non-abraders.

The following statistics were derived from the study:

Brushing frequency. Abraders brushed 10.3 percent more often each day than did non-abraders. While abraders brushed an average of 2.25 times, the non-abraders brushed 2.04 times.

Abraders were more likely to brush 3 times a day than non-abraders who more often brushed twice. Brushing more frequently, especially if too forcefully, exposes the teeth and gums to an increased risk of abrasion. Brushing frequency considered by itself, however, does not predict toothbrush abrasion.

Flossing frequency. Abraders flossed 31.9 percent more often each week than did non-abraders. They flossed an average 3.35 times while non-abraders flossed 2.54 times.

Abraders appear to have a greater awareness and higher standards for oral hygiene. This has also been shown in several studies and may be one reason that detecting patients with this dental risk is often overlooked. Abraders often have very clean teeth and gums.

Bristle hardness. The difference in bristle stiffness used among abraders and others differ by a minimal 2.3 percent, as most use either soft or medium stiffness. This is an interesting finding, considering that bristle stiffness was once thought to be the primary cause of abrasion.

While soft-bristled, polished, and end-rounded toothbrushes are preferred for all patients, especially those who brush forcefully, the data in this study indicate stiffness is not a significant factor in abrasion and is in agreement with other studies.

Perceived brushing pressure. Abraders rated themselves as apt to brush 12.7 percent harder. This rating was subjective because patients were not observed for brushing force. The data stands on its own merit. Abraders, who typically have high standards of oral cleanliness, also admit to applying more brushing pressure.

Clearly, some patients may believe that brushing harder equates to brushing better. Hygienists may need to educate some of their patients about the fallacy of such a belief.

Toothbrush replacement frequency. Abraders replace their toothbrushes 48.8 percent more often. Their toothbrushes were replaced approximately every three months as opposed to every 4.5 months for non-abraders.

This is an important statistic. Patients generally replace their brushes because the bristles wear out and become splayed. Splaying is caused by forces that exceed the elastic limit of the bristle and lead to permanent bending. Accordingly, the greater the force exerted, the more splaying and bending of bristles occur.

The greater level of force, of course, is applied directly to the teeth and gums. As a result, a greater amount of oral mucosa and tooth structure is removed.

Toothbrush replacement frequency and replacement condition, discussed in the next section, are two factors that, when considered alone, are indirect indicators of imminent abrasion damage. The mathematical product of the answers to these two questions actually measure the damage inflicted to the teeth and gums by the toothbrush. It can be very useful in diagnosing abrasion even in its earliest stages.

Toothbrush replacement condition. Both groups typically replace toothbrushes when bristles are between slightly and moderately bent and distorted. A slightly higher number of abraders have brushes in worse condition. This factor is indicative of abrasion, but on its own is not predictive.

Knowledge about incorrect tooth brushing. Abraders have a slightly higher (4.5 percent) awareness about the potential damage brushing could cause to their dentitions. Even though they may be more aware of the risks, abraders display the most damage.

While awareness about a potential risk factor is one thing, knowledge about what specific factors increase that risk is another. Clearly, some level of knowledge about what proper brushing force is has not been taught or learned.

Length of brushing time. In addition to brushing more often, abraders also brush an average of 14.4 percent longer each brushing session. This is consistent with the personality characteristics demonstrated by responses to questions about brushing, flossing, and perceived brushing pressure.

Most people, we must remember, do not time themselves. They do not know exactly how long they typically brush their teeth. So these figures may be off considerably.

High awareness doesn`t stop abrasion

This particular study found that 66.1 percent of the patients surveyed had signs and symptoms of toothbrush abrasion. This is consistent with a similar survey done in the 1940s by Ervin and Bucher. Additionally, 70 percent of the abraders knew that brushing could damage their gums, teeth, or both (64 percent of the non-abraders were aware of this).

The general population appears to understand that brushing, like other forms of friction, can cause wear - even to the teeth and gums. This level of awareness about abrasion, though, does not match up with the level of knowledge on how to deter abrasion without compromising good oral health.

This is information that hygienists must share with their patients, especially those who show behavioral signs of imminent risk.

This study sought to pinpoint the behavioral characteristics that allow practitioners to identify and predict which patients have overly abusive habits and are likely to develop symptoms of abrasion. When anayzing the data, we developed a chronic index of abrasion.

With the index and the patient`s answers to questions, one can predict with 86 percent accuracy which patients are likely to develop and continue abrasion problems. Because the amount of force on the brush is the same amount applied to the teeth and gums, we can gather a good picture about the amount and the result of such force by using this index.

The index is calculated by multiplying the scores on the survey`s sixth (toothbrushes per year) and seventh (damage per toothbrush) questions. Any patients who score higher than six are likely to be abraders and warrant preventive measures, such as the toothbrush described above with the built-in sensor.

Clearly, toothbrush abrasion is a dental health problem that has received many years of attention but has met with little success in being eliminated. Early diagnosis and prevention are the keys.

While treatments for abrasion-related problems are well developed by this time, eliminating the problem from the get-go means detecting the behavioral as well as physical signs of abrasion and offering patients effective ways to prevent damage.

References available upon request from the author at (800) 225-3780.

Eric L. Spieler, DMD, is a selectives faculty member of the University of Pennsylvania School of Dental Medicine in Philadelphia. He is also president of Bioware Inc. in Bala Cynwyd, Pa. He maintains a private practice in Philadelphia.