Dental Flossing and Interproximal Caries: a Systematic Review

Our aim was to assess, systematically, the effect of flossing on interproximal caries risk. Six trials involving 808 subjects, ages 4 to 13 years, were identified. There were significant study-to-study differences and a moderate to large potential for bias. Professional flossing performed on school days for 1.7 years on predominantly primary teeth in children was associated with a 40% caries risk reduction (relative risk, 0.60; 95% confidence interval, 0.48–0.76; p-value, < 0.001). Both three-monthly professional flossing for 3 years (relative risk, 0.93; 95% confidence interval, 0.73–1.19; p-value, 0.32) and self-performed flossing in young adolescents for 2 years (relative risk, 1.01; 95% confidence interval, 0.85–1.20; p-value, 0.93) did not reduce caries risk. No flossing trials in adults or under unsupervised conditions could be identified. Professional flossing in children with low fluoride exposures is highly effective in reducing interproximal caries risk. These findings should be extrapolated to more typical floss-users with care, since self-flossing has failed to show an effect.

Microwave disinfection of dentures for the treatment of oral candidiasis

Thirty-four institutionalized subjects (mean age, 81 years) with a positive test for C. albicans pseudohyphae were randomly assigned to test (microwave) and control (soak) groups. All subjects received the same course of topical antifungal medication (Nystatin 300,000 IU lozenges 3x daily for 14 days). Subjects in the microwave treatment group had their maxillary denture scrubbed and then microwaved for one minute at 850 Watts. This procedure was repeated three times. For subjects receiving the standard denture soak treatment, the nursing staff was instructed to disinfect the maxillary dentures in 0.2% chlorhexidine digluconate solution overnight for 14 days, changing the solution every two days. Infestation of the tissue surface of the maxillary denture with C. albicans progressively took place over the three-month period following treatment such that 8 (53%) of the microwaved dentures and 16 (84%) of the soaked dentures demonstrated pseudohyphae as determined by Gram stain. Infection of the soft tissues with the hyphal form of C. albicans also increased with time. After three months, one (8%) patient in the microwave group and 12 (63%) patients in the denture soak group demonstrated pseudohyphae on the cytological smears. Re-infestation of the denture surface and infection of the adjacent soft tissue were delayed dramatically in patients whose dentures were microwaved compared with those whose dentures were disinfected by being soaked in a chlorhexidine solution. However, microwave treatment is not recommended for all dentures and should be used with caution.

The diagnosis of root caries

The most commonly used clinical signs of root caries are visual (color, contour, surface cavitation) and tactile (surface texture) descriptions of a lesion. The traditional methods of visual-tactile diagnosis for root caries can produce a correct diagnosis but usually not until the lesion is at an advanced stage. Despite the subjectivity inherent in interpreting the clinical signs of root caries diagnosis, good to excellent inter-examiner reliability has been reported in clinical studies; however, the presence of filled surfaces dramatically enhances the agreement. When only untreated root caries is diagnosed, examiner reliability is reduced considerably. Clinicians look to diagnostic tests in the hope that they will perform better (that is, be more reliable) than clinical diagnosis and, therefore, can be used to replace clinical diagnosis. From the limited data available on diagnostic tests for root caries, tests determining the presence or absence of mutans streptococci and Lactobacilli are the most clinically helpful, producing calibrated efficiency scores exceeding 40 percent. The risk assessment approach to root caries diagnosis involves the determination of a patient's risk through the interpretation of clinical signs and the selection and application of an appropriate diagnostic test if the clinician is unsure of the diagnosis.

The effectiveness of 10% chlorhexidine varnish treatment on dental caries incidence in adults with dry mouth

OBJECTIVES

This study compared a 10% chlorhexidine varnish treatment with placebo and sham treatments for preventing dental caries in adult patients with xerostomia (dry mouth).

DESIGN

The study was a multicentred, randomized, parallel group, double blind, placebo-controlled clinical trial.

SETTING

All examinations and procedures were performed at Tuft's University, Boston, MA, the University of British Columbia, Vancouver, BC or the University of Western Ontario, London, ON.

SUBJECTS

Subjects were adults with recent or current dental caries experience, high salivary levels of cariogenic microorganisms and low salivary flow rates.

RESULTS

236 subjects completed at least one post-treatment examination. There were 697 new carious lesions diagnosed, 446 (64%) located on coronal surfaces and 251 (36%) located on root surfaces. The mean attack rate was 0.23 surfaces/100 surfaces at risk. A treatment difference observed between the Active and Placebo groups was statistically significant for root caries increment (p = .02) and total caries increment (p = .03). A treatment difference observed between the Active and Sham groups was not statistically significant for coronal, root or total caries increment. Analysis of variance of treatment group differences was performed using mutans streptococci counts, salivary flow rates, age, sex, caries prevalence, medications, time to first event and early withdrawal as co-variables. These factors did not meaningfully alter the findings.

CONCLUSIONS

The difference between the 10% chlorhexidine varnish and placebo treatments is considered to be highly clinically significant for root caries increment (41% reduction) and for total caries increment (25% reduction) but only for coronal caries increment (14%).

Effect in vitro acidification on plaque fluid composition with and without a NaF or a controlled-release fluoride rinse

Plaque fluid ion concentration changes, especially fluoride, in response to the pH decrease associated with a cariogenic episode are important components of the caries process. A "controlled-release" (CR) fluoride rinse, based on the controlled release of fluoride in the presence of calcium, has been shown to form large fluoride reservoirs in resting plaque. In this study, the in vitro acid-induced release of fluoride, and other ions, was examined in 48-hour-fasted plaque fluid from subjects (n = 11) who received no rinse, or who used a 228-ppm CR or NaF fluoride rinse 1 hr before being sampled. After collection, the plaque was centrifuged to yield plaque fluid, acidified (0.1 microL of 0.5 mol/L HCl per milligram plaque), and then re-centrifuged before a second sample was obtained. Although previous studies indicated a higher plaque fluid fluoride after the new rinse relative to NaF, no statistically significant difference was observed here. Average fluoride release after acidification (average pH, 5.2) was statistically greater following the use of the CR rinse (153 micromol/L) compared with the NaF rinse (17 micromol/L). No fluoride release was seen in the no-rinse samples. The pH, free calcium, phosphate, acetate, propionate, and buffer capacity were not affected by the different amounts of fluoride deposited in the plaque. However, following acid addition, an increase in free calcium and phosphate was observed, which was also independent of the rinse. The large release of fluoride following acidification suggests that the new rinse may provide an improved cariostatic effect.

Effect of beta-adrenoreceptor blockade with nadolol on the duration of local anesthesia

BACKGROUND

beta-adrenoreceptor blockers, or beta-blockers, are drugs commonly prescribed for hypertension, angina and migraine headaches. In a patient taking beta-blocker medication, administration of a local anesthetic containing a vasoconstrictor could result in an adverse interaction.

METHODS

The authors conducted a double-blind, randomized, crossover, placebo-controlled study to test the hypothesis that a nonselective beta-blocker--nadolol--enhances vasoconstriction induced by the epinephrine contained in local anesthetic, thus resulting in an increased duration of anesthesia. Ten healthy male volunteers were given either a placebo or a single, standard oral dose of nadolol (80 milligrams). The upper lateral incisor teeth were anesthetized using lidocaine with or without epinephrine.

RESULTS

The mean duration of pulpal and soft-tissue anesthesia was increased in subjects who took nadolol compared with those who took placebo by 17 minutes (58 percent) and 16.5 minutes (19 percent), respectively, when they received 1 milliliter of lidocaine containing 1:100,000 epinephrine. These differences were both clinically and statistically significant (P = .007). Using lidocaine without epinephrine produced no clinically or statistically significant difference in duration of pulpal or soft-tissue anesthesia in the two groups of subjects. The authors noted no significant changes in blood pressure or pulse rate.

CONCLUSIONS

Administration of local anesthetic containing epinephrine to subjects receiving a beta-blocker increased the duration of pulpal and soft-tissue anesthesia. There was no difference in duration of anesthesia between groups when local anesthetic without epinephrine was used.

CLINICAL IMPLICATIONS

Use of local anesthetic containing a vasoconstrictor should be avoided in patients taking beta-blocker medication because of a possible adverse drug interaction. However, when a vasoconstrictor is indicated for hemostasis, the local anesthetic should be administered slowly and in small amounts as pulse rate and blood pressure are being monitored. The patient should be informed that the duration of anesthesia might be prolonged.

International fluoride supplement recommendations

A telefax survey was conducted to determine the current and past recommended schedules for fluoride supplementation using tablets, salt or milk. Twenty-one of 90 countries listed in the 1997 FDI directory responded. Information on additional countries was gathered from a recent textbook on fluoride and a dental health survey report. The summary table provided is far from comprehensive but it represents the best data available at this time. The conclusions are limited to the information received but there is a clear trend to lower dosage recommendations and no fluoride supplementation to very young children. Several issues are identified which should be addressed whenever fluoride tablet supplementation schedules are being considered.

The use of diagnostic tests to aid clinical diagnosis

Clinical decision making in dentistry involves some uncertainty and error, but in the absence of good clinical research it is often more of an art than a science. This article demonstrates a way in which clinicians can consistently and effectively base the diagnostic process on scientific evidence. The authors examine the selection and utility of supplemental diagnostic tests, describe the properties of these tests, and explain how test results can be used to augment clinical opinion. To aid the dental clinician in the decision making process, a step-by-step strategy is presented for the detection of squamous cell carcinoma using toluidine blue dye.

Effectiveness of a topical antifungal regimen for the treatment of oral candidiasis in older, chronically ill, institutionalized, adults

Because of predisposing systemic disease, the frequent administration of medication, and the use of a complete denture, oral candidiasis is a common problem among older, chronically ill, institutionalized adults. This randomized clinical trial was designed to evaluate the effectiveness of an antifungal denture soaking solution (48 mL nystatin liquid, 100,000 IU/mL, dissolved in 432 mL of distilled water producing 10,000 IU nystatin mL solution), used as an adjunct to a nystatin vaginal lozenge (100,000 IU/g, dissolved in the mouth three times daily for seven days) in a group of older, chronically ill, institutionalized adults. Although the clinical signs and symptoms of oral candidiasis were resolved in all subjects following therapy, the presence of invasive Candida hyphae was detected in approximately 80 per cent of tissue and/or dentures. When compared to tap water, the use of an antifungal denture soaking solution produced no detectable difference in the presence of Candida albicans hyphae over a three-month period (M-H chi-square = 0.021, p = 0.886), but it did reduce the rate of recurrence of clinical signs and symptoms. The appropriateness of this regimen for the treatment of oral candidiasis in this type of patient is challenged.

Water fluoridation: current effectiveness and dental fluorosis

This paper reviewed the literature on the evidence for water fluoridation's effectiveness under current conditions of multiple fluoride use at recommended and at reduced concentrations, the extent of dental fluorosis at different fluoride concentrations, and the "halo" effect of water fluoridation. Using the relative difference in dental caries between communities with low and optimal water fluoride as an indicator, the effectiveness of water fluoridation has decreased over time as the use of other fluorides has increased. Thus the effectiveness of water fluoridation alone cannot now be determined. Compared to the early fluoridation studies, the differences in dental caries and fluorosis prevalence between fluoridated and non-fluoridated areas have markedly narrowed. Both the prevalence and severity of dental fluorosis have increased since 1945; however, the portion of fluorosis due to water fluoridation is now less (40%) than that attributed to other fluoride sources (60%). Research also suggests that the "halo" effect of community water fluoridation may result in a significantly greater intake of fluoride for people in non-fluoridated communities. This review recognized that since water fluoridation has unique advantages from the perspectives of distribution, equity, compliance and cost-effectiveness over other fluoride technologies, it remains as the fundamental base for caries prevention. The increasingly greater contribution that other sources of fluoride make to dental fluorosis suggests that these sources of fluoride, many of which are used on an elective basis, should be more closely examined for needed changes.

Future directions for root caries research

Interest among researchers in the diagnosis, aetiology, prevention, and treatment of root caries has increased substantially over the past two decades. However, there are some fundamental problems impeding the advancement of the field which remain to be addressed and resolved. A universally acceptable definition of root caries is not yet available. The relationship of root caries to coronal caries has not been established. The underlying disease process is still not clearly understood. The optimal utilisation of preventive/therapeutic agents for the treatment or prevention of root caries has not been determined. New treatment materials and preventive agents have not yet been tested in controlled clinical trials. These are a few of the issues and problems which we address in this paper.

Diagnosis and prediction of root caries

Diagnosis is the process of recognizing diseases by their characteristic clinical signs and symptoms. Diagnostic ability varies considerably between and among examiners, and, consequently, the accuracy of the diagnosis can be questioned. Root caries is a disease for which there are several clinical signs (location, color, surface texture, and surface cavitation). Unfortunately, these signs are open to broad clinical interpretation. As a result, estimates of disease occurrence (incidence rate) have ranged from 0.87 to 8.20/100 surfaces at risk/year or 0.15 to 0.43 lesions/person/year for adults living independently in the community. When multiple examiners are utilized, interexaminer agreement has been reported to be relatively good but could be further improved by minimizing the effects of several sources of examiner disagreement, including the absence of a global consensus on the signs which indicate the presence of root caries. The use of a diagnostic test can enhance the diagnosis and prediction of root caries, but the development of useful tests is hindered by the lack of an accurate clinical standard of diagnosis. At this time, diagnostic tests for root caries are quite limited and of questionable value. A powerful predictive tool for root caries would result from the combination of risk assessment measures and a valid diagnostic test developed with use of standardized and accurate methods of clinical diagnosis.

Adult root caries survey of two similar communities with contrasting natural water fluoride levels

For a comparative study of root caries, 502 adult lifelong residents of a naturally fluoridated community (1.6 ppm F) and 465 such residents of a nearby, comparable nonfluoridated community (0.2 ppm F) were examined. Substantially fewer carious lesions were found among adults in the fluoridated community relative to the nonfluoridated community. This was observed in virtually all age- and gender-specific groups. Given a cross-sectional design and considering only exposed root surfaces, root caries was related to age. In addition, the data from this study show that the number of root caries lesions is underestimated but that root caries prevalence is overestimated by the standard Root Caries Index (RCI). A less restrictive form of the RCI may lead to more valid estimation of root caries prevalence.

Longitudinal microbiological investigation of a hospitalized population of older adults with a high root surface caries risk

Intact root surfaces of chronically hospitalized subjects were sampled periodically to enumerate bacterial species believed to be associated with root caries. Bacteria were cultivated and enumerated using a series of selective and enriched media. Microbial counts, isolation frequencies, and percent cultivable flora data were analyzed for caries-active and caries-free surfaces and subjects. S. mutans, S. sanguis, A. viscosus, A. naeslundii, total lactobacilli, and Veillonella accounted for a mean of less than 20% of the cultivated flora, with mitis salivarius agar cultivable streptococci averaging less than 5%. The microbial count data were highly variable, precluding the finding of significant differences in caries association for either subjects or sites. Streptococci, especially S. mutans, correlated highly with lactobacilli in the samples.

Streptococcus mutans and Lactobacillus detection in the assessment of dental root surface caries risk

Forty-five subjects contributing 150 root surfaces with gingival recession were sampled seven times over a 32-month period. We calculated isolation frequencies of lactobacilli on selective Rogosa SL agar and S. mutans in a sensitive enrichment broth and on mitis salivarius agar. Both S. mutans and lactobacilli were isolated more frequently from surfaces which became carious than from those remaining caries-free. Isolation frequencies were also higher for caries-free surfaces in caries-active subjects than for caries-free surfaces in caries-inactive subjects. The presence or absence of S. mutans and lactobacilli in samples taken at baseline could discriminate between subjects who were to be root-caries-active and those who were to remain root-caries-inactive during the subsequent observation period. Moreover, if both bacteria were detected or only S. mutans was detected on a root surface at its entry into the study, that surface had a greater risk for developing a root lesion. However, the tests could not predict which root surfaces within the mouths of caries-active subjects were to become carious. Analysis of the data suggests that simple microbiological detection tests may be useful in identifying patients at high risk of root caries.

A further look at the role of radiographs in trials of caries-prophylactic agents

To determine the role of bitewing radiographs in clinical trials of caries prophylactic procedures, data from the Chatham flossing study 26 were reanalyzed. The final examination records after 20 months of 147 second grade children were used to assess and compare the separate and combined results from clinical and radiographic examinations. Analysis of paired approximal surfaces from contralateral test and control quadrants revealed that the addition of radiographic findings to clinical data changed the mean increment reduction from 22 to 26 percent. This slight increase was further supported by the results of similar studies which reported either separate or combined radiographic and clinical findings or both. Although the magnitude of the increase of the mean increment reduction remains uncertain, data from these studies indicate that the use of combined radiographic and clinical data might be justified when testing a particular prophylactic procedure which is expected to incur a significant caries reduction to approximal surfaces. Furthermore, findings suggest that clinical trials of certain prophylactic agents that are particularly beneficial to approximal surfaces, but which fail to include radiographic examinations, might actually underestimate the preventive effect of the agent.

Prevalence of root surface caries among institutionalized older persons

Fifty-nine residents of a chronic hospital (average age 67.9 years) were examined visually for root surface caries. Root lesions were found to be present in 44 of the residents and were located most frequently on the proximal surfaces of anterior teeth. The number of coronal DF surfaces, age and number of retained teeth were the factors found to be helpful in discriminating between persons with and without root surface caries.

Comparison of selective broth and plating methods for isolation of Streptococcus mutans from root surface dental plaques

Approximately 150 sound root surfaces in 44 subjects prone to root surface caries were sampled longitudinally to determine the microbial flora associated with root caries initiation. During the first 16 months of the study, a comparison of Streptococcus mutans recovery was made by using three bacteriological media: mitis-salivarius agar (MSA), mitis-salivarius-bacitracin-sucrose agar (MSB), and a partially selective mannitol-containing broth. Total streptococcal and S. mutans populations were found to be much lower than in previous reports. MSB was more selective; S. mutans was detected in many samples when its numbers were too low for isolation on MSA. However, recovery of S. mutans was greater on MSA than on MSB for most samples yielding colonies on both media. Mannitol-containing broth used as an enrichment medium yielded the highest frequency of S. mutans isolation among the three media.

Effect of interdental flossing on the incidence of proximal caries in children

A clinical study was designed to evaluate the effect of frequent interdental flossing on the incidence of proximal dental caries. School children from a fluoride-deficient area were studied after clinical and radiographic examinations. Each child had at least one contralateral pair of intact, contacting proximal tooth surfaces between the distal surface of the primary cuspid and the mesial surface of the first permanent molar. Randomly selected test surfaces were flossed each school day with unwaxed dental floss by researchers. The contralateral surfaces served as controls. Flossing was done for eight months, discontinued for four months, and reinstituted for another eight months. A significant reduction in the incidence of proximal caries resulted.