Oral Hygiene: Past, Present, and Future

Early in human history, oral self-care targeted impacted food and problematic teeth. Although the ancients knew nothing about the biology of oral diseases, rudimentary self-care tools included chewing sticks, twigs, feathers, and animal bones. Over the past century, efforts to optimize oral hygiene as a means to enhance prevention or to limit disease progression have increased.¹

In the 1930s “see your dentist twice a year” and “brush your teeth twice a day” became popular aphorisms. Despite this, nearly a century later, no quality evidence exists to support such claims. However, it now seems clear that some people need frequent professional care and intensive self-care, while others need less.²

Increased societal interest in dental health was an indirect effect of World War II, when many military draftees were rejected because of extremely poor oral health. This led to the creation of the National Institute of Dental Research in 1948. Research later confirmed that dental film (ie, dental plaque and the more recently termed dental biofilm) played an important role in the etiologies of dental caries and periodontal diseases. Once dental plaque was identified as causal for caries and the periodontal diseases, the biological rationale for optimal oral hygiene became clear.³

Pre- and post-WWII advertising by dentifrice companies motivated patients to improve self-care, and also encouraged professionals to increase professional oral hygiene services. Eventually, it became clear that the amount of dental plaque did not always correlate with the likelihood or severity of dental diseases. Rather, it became evident that the bacterial makeup and the anatomic location of the plaque were more critical determinants of oral health or disease.⁴ It also became apparent that undisturbed dental plaque changes in character over time, typically becoming more harmful.⁵

Dental calculus (ie, tartar) has long been linked with poor esthetics and periodontal diseases. Calculus removal was often a key focus of early dental hygienists and dentists. Later came evidence that calculus, per se, was not causal, but rather the bacteria that populated it could cause periodontitis. This led to confusion regarding the importance of preventing or removing calculus. It now appears that the frequent removal of all macroscopically visible calculus, whether supragingival or subgingival, is part of any regimen aimed at ensuring optimal oral health.⁶

By the 1930s, epidemiological studies reported lower caries rates in some localities. Higher concentrations of fluoride ions dissolved in municipal water supplies were implicated. Although technically not self-care, beginning in 1945, low concentrations of fluoride were added to more municipal water supplies. Unfortunately, the enamel component of teeth tends to become undesirably mottled if dietary fluoride is too high.⁷ Some experienced mottling, even in cities where fluoride concentration was held to only 1 part per million. Therefore, the recommended concentration of fluoride in water supplies is now 0.7 parts per million.⁸

Dentifrices (toothpastes) began replacing dental powders in the 1920s and 1930s. Diluted sodium lauryl sulfate detergent became a popular component of dentifrices because a sudsy mix contributed to patients’ post-brushing perceptions of cleanliness.

In recent years, the addition of specific ingredients to dentifrices and rinses has been found to better mitigate existing caries and gingival diseases, especially when those maladies are addressed in their nascent stages. In the 1960s, fluoride was added to dentifrices (later to mouthrinses) to inhibit caries. Agents (eg, pyrophosphate) were added to inhibit the formation of dental calculus. The antiseptic triclosan was compounded in some dentifrices; it promptly kills bacteria and is substantive, meaning it remains active for hours after its application. All of these additives have been shown to be at least somewhat beneficial. Some dentifrices include more than one active ingredient and show efficacy against both caries and gingivitis.

Bioactive agents have also been introduced into appliqués and mouthrinses. Among these ingredients are fluorides, essential oils, quaternary ammonium compounds (eg, cetylpyridinium chloride), and chlorhexidine. Many offer better means to assist certain patients, especially caries-prone children and the elderly.^9,10

Rinses are popular; a rinse containing “essential oils” has been advertised as a germicide for a century. It is somewhat effective against the mildest of the periodontal diseases, namely gingivitis. Chlorhexidine rinses are substantive and highly potent antimicrobials, but stain teeth and may affect taste sensation. Such shortcomings make chlorhexidine rinses appropriate for brief intervals.

Powered toothbrushes were first introduced in the 1960s. When properly used, ample evidence exists to support their superiority. However, manual toothbrushes can achieve similar results but with more effort.

Tongue cleaning has gained popularity in recent years based on the observation that the tongue’s rough dorsum harbors bacteria that can facilitate the microbial repopulation of newly cleaned teeth. Data also suggest effectiveness against halitosis.¹¹

Some of what follows may seem fanciful. The key to widespread implementation is whether each makes sense from a cost (risk)-versus-benefit standpoint.

Individualized diagnostics, including genetic tests, will better identify those who need more intensive oral hygiene interventions. Ideally, such information would be available and acted on early enough in life to prevent or limit caries and the periodontal diseases. Delta Dental of Michigan introduced a program in which patients at lower risk for oral disease are benefited for fewer periodic prophylaxes and examinations. Those who test at higher risk are benefited for additional professional interventions. Such programs appear likely to spread. Although notionally sound, these efforts are based on average responses and may be confounded by an administrative bias against tobacco users. Thus, the risk is that some who are examined less often may incur otherwise-avoidable oral health problems.

As the average age of Americans increases, oral hygiene emphasis will be multimodally enhanced for invalids and those for whom better oral health may translate into decreased risk or morbidities for systemic diseases.

There will be improved understanding (among professionals and patients) of preventive care aimed at the completely or partially edentulous, with or without osseointegrated implants. Those with complete dentures infrequently visit dental professionals, thereby putting themselves at a greater risk for delayed discovery of less common oral diseases, such as advanced squamous cell carcinoma. Similarly, it remains unclear whether or how oral health may be causally linked to the growing incidence of oropharyngeal cancer caused by sexually transmitted human papillomavirus.

After more than 35 years of osseointegrated dental implants, dentistry is now more widely addressing implant maintenance issues. It should come as no surprise that the same patient-specific causes of natural tooth loss may also put implants at risk. Indeed, it has become increasingly clear that oral hygiene tactics designed for implants are critical to successful maintenance.

The causal links between oral health and systemic health will become better known by the public, thereby driving increased attention to optimal oral hygiene.

Improved availability of internet-based services will enhance the average information technology capabilities of tomorrow’s patients. Tactics to guide users to reputable sources of information will become better and more successful.

Michael P. Rethman, DDS, MS
Adjunct Faculty Member
University of Maryland and The Ohio State University
Adjunct Clinical Assistant Professor
College of Dentistry
The Ohio State University