The etiology and pathogenesis of dental caries are known to be multifactorial, but the interplay between intrinsic and extrinsic factors is still not fully understood. As in other host/parasite interactions, there appear to be marked variations in individual susceptibility to the disease. It therefore is likely that intrinsic host factors play a key role in modulating the initiation and progression of caries. The objective of this systematic review was to evaluate critically the evidence supporting the role and effects of saliva in caries pathogenesis. The full-length evidence report, including evidence tables, and the structured abstract presented at the NIH/NIDCR Consensus Development Conference on the Diagnosis and Management of Dental Caries Throughout Life, March 26-28. 2001, can be accessed at the web site http://www.nidcr.nih.gov. The present abridged report is a summary of the main findings from our evidence-based review.

Physical and chemical aspects of saliva as indicators of risk for dental caries in humans

The purpose of this review was to evaluate the literature on the rehabilitation of tooth wear, with some pertinent historical, epidemiological and aetiological aspects of tooth wear provided as background information. In historical skull material, extensive tooth wear, assumed to be the result of coarser diets, was found even in relatively young individuals. Such wear is seldom seen in current populations. Although many of the factors associated with extensive tooth wear in historical material are no longer present or prevalent, new risk factors have emerged. In the young individual, the literature points to a global rise in soft drink consumption as the most significant factor in the development of tooth wear through dental erosion. Among older individuals, lifestyle changes and chronic diseases that are controlled with medications that may, in turn, result in regurgitation and/or dry mouth, are possible reasons amongst others for the widespread clinical impression of an increasing prevalence of tooth wear. The aetiology of tooth wear is multifactorial and the role of bruxism is not known. Clinical controlled trials of restorative and prosthodontic approaches for the range of clinical conditions that wear can give rise to, are limited in number and quality. Equally, the striking lack of evidence regarding the long-term outcomes of treatment methods and materials calls for caution in clinical decision-making. Notwithstanding these observations, clinicians have provided and continue to provide rehabilitative strategies for managing their patients' worn dentitions that range traditionally from extensive prosthodontics to an increasing reliance on adhesive techniques.

Rehabilitation of the worn dentition.

– Objectives:  Several studies have been conducted on the prevalence of hyposalivation in older adults but no population-based studies in younger adults. Therefore, our aims were to determine the prevalence of very low and low unstimulated (UWSFR) and stimulated (SWSFR) whole salivary flow rates in different age groups between 20 and 69 years, and to analyse the relationship between hyposalivation, subjective oral dryness and predictors of reduced flow rate.



Methods:  A randomized and stratified cross-sectional study including 1427 dental patients was conducted. UWSFR and SWSFR were measured, numbers of remaining teeth recorded and a questionnaire answered regarding subjective oral dryness, general diseases, use of drugs, body mass index (BMI) and use of tobacco.



Results:  The prevalence of very low (  25 for very low UWSFR and diagnosed disease for very low SWSFR were found significant. In this younger subset, female gender combined with having fewer than 27 teeth was significant for low UWSFR.



Conclusions:  Hyposalivation is prevalent in younger adults, among whom it is associated with diagnosed disease and high BMI, while after age 50 years it is associated with medication. It is also associated with gender and with fewer remaining teeth.

Prevalence of hyposalivation in relation to general health, body mass index and remaining teeth in different age groups of adults.

Gastric juice entering the mouth causes dental erosion. Common causes for the migration of gastric juice through the lower and upper oesophageal sphincters are reflux disease, laryngopharyngeal reflux, eating disorders, chronic alcoholism and pregnancy. Gastroesophageal reflux is a common condition affecting up to 65% of the Western population at some point in their lifetime. A typical clinical sign of acidic gastric juice entering the mouth is palatal dental erosion. As the condition becomes more chronic it becomes more widespread. There have been relatively few randomised studies investigating the aetiology of acids causing erosion. Of the few that have reported their findings, it appears that gastric acids have the potential to induce moderate-to-severe erosion. This literature review reports the conditions associated with the movement of gastric juice and dental erosion using medical and dental sources.

Intrinsic Causes of Erosion

Since the mid-1990s, the focus of studies on tooth wear has steadily shifted from the general condition towards the more specific area of dental erosion; equally, a shift has occurred from studies in adults to those in children and adolescents. During this time, understanding of the condition has increased greatly. This paper attempts to provide a critical overview of the development of this body of knowledge, from earlier perceptions to the present. It is accepted that dental erosion has a multifactorial background, in which individual and lifestyle factors have great significance. Notwithstanding methodological differences across studies, data from many countries confirm that dental erosion is common in children and young people, and that, when present, it progresses rapidly. That the condition, and its ramifications, warrants serious consideration in clinical dentistry, is clear. It is important for the oral healthcare team to be able to recognize its early signs and symptoms and to understand its pathogenesis. Preventive strategies are essential ingredients in the management of patients with dental erosion. When necessary, treatment aimed at correcting or improving its effects might best be of a minimally invasive nature. Still, there remains a need for further research to forge better understanding of the subject.

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Dental erosion and its growing importance in clinical practice: from past to present.

The aim was to explore possible correlations between the oral status of patients undergoing treatment at a special outpatient psychiatric clinic for eating disorders and such variables as psychiatric diagnosis and duration of illness, oral hygiene habits, salivary function, and dietary habits. Healthy volunteers of a similar age were recruited for comparison. The material comprised 100 consecutive referrals, of whom 79 were women and 2 were men (age range 17 to 47, median 25 yr) participated. The eating disorders were diagnosed according to the American Psychiatric Association's DSM III-R criteria. The clinical and radiographic examinations were supplemented by standardized intraoral photographs, study models and salivary analysis. The decayed, missing, filled surfaces (DMFS) index was 15.3+/-10.9, a significantly higher caries frequency than for the reference group. More than half the subjects had erosive tooth wear involving the dentine, and about one-third had very low unstimulated salivary flow rates and very high counts of mutans streptococci and lactobacilli. Erosive tooth wear was significantly correlated to the number of years of binge-eating. Compared to age-matched individuals, subjects with diagnosed eating disorders are more susceptible to both dental caries and erosion. They should be encouraged to adopt appropriately tailored preventive programmes and to have regular dental check-ups.

Oral status of 81 subjects with eating disorders.

The aim was to record changes over time in the oral status of subjects with diagnosed eating disorders. The outpatient psychiatrist had referred to the hospital dental clinic 35 women (19–47 yr, median 27 yr) with eating disorders, diagnosed according to DSM III-R criteria. At the baseline examination, dental, medical and dietary histories were taken, and intra-oral clinical and radiographic examinations were supplemented by intra-oral photographs, study casts and salivary analysis. The subjects were re-examined 1 yr later. Together, the investigators assessed progression of tooth wear blindly by comparing coded study casts from the baseline and 12-month examinations. Progression of erosive tooth wear was recorded in almost half of the subjects. Several subjects had low unstimulated salivary flow rates (<0.1 ml/min) and very high counts of mutans streptococci and lactobacilli, both at baseline and 1 yr later. The flow rates for paraffin-stimulated saliva at baseline were significantly lower for subjects with progression of erosive tooth wear than for those without. Because of the increased susceptibility to both caries and erosion, patients with eating disorders should be encouraged to have regular dental check-ups. Test of salivary flow may serve as an indicator of patients' risk of progression of erosive tooth wear.

Rolf Öhrn

Papers

Oral status of 81 subjects with eating disorders.

Oral status of 35 subjects with eating disorders--a 1-year study.