How to measure the effects of fluoride treatments in clinical trials? Assessment: modern versus traditional methods

In recent years there has been a pronounced change in the epidemiology and disease pattern of dental caries. In the current context, traditional methods of caries assessment, discriminating lesions at cavitation, are clinically inappropriate, and obsolete for research requiring detection of a very early phase of mineral loss. Modern prospective caries studies require sensitive methods permitting the measurement of small changes in tooth mineral content, and objective, quantitative measurements of such changes are now possible in a single caries lesion. For longitudinal studies there are noninvasive methods for assessment of new lesions as well as quantitative changes (progression or regression) in existing lesions. Among as yet unresolved issues are improved methods to assess the current activity of a lesion, methods for detection and quantification of secondary caries and root caries, calibration of methodologies between different research institutes, and methods capable of assessment of the whole continuum in the development of a caries lesion, from initial loss of mineral to cavitation.

Take two dentists: a tale of root caries

Take two dentists, whose practices are about as different as they could possibly be, who both have a healthy respect for root caries. Our paper will start by describing these two practices and then review the literature to show what is known about the management of root caries. The paper ends by returning to the two dentists, who describe how the research reviewed in the literature may affect their work.

Root caries among Benghazi patients

A total of 420 Benghazi patients were clinically examined for root caries. Root caries was not limited to older patients and the proportion of root caries among young adults was similar to that of the older age groups. Most of the lesions were located proximally and underneath restorations rather than labially or lingually. Our results may serve as baseline data for further studies on root caries in the Libyan Arab Jamahiriya.

Issues in the treatment of root caries in older adults

Increased life expectancy, improvements in tooth retention, and higher expectations about oral health will continue to result in an increased demand for esthetic restorative dental care. Using demographics as a predictor of future dental treatment needs, root caries may be one of the most significant patient management issues of the next decade. Root caries also can present the clinician with challenging restorative problems. The best treatment option is determined by the lesion, the caries rate, the condition of the patient, and the esthetic requirement or desire. Material selection is critical for successful restoration of root caries. The treatment of root caries also should include methods for the prevention of future lesions. Although caries risk assessment is not a perfected science, models can assist in estimating caries risk and then guide the clinician toward the most suitable preventive approach.

A study of the classification and treatment of noncarious cervical lesions by general practitioners

PURPOSE

This study presented a survey to determine what general practitioners in Nova Scotia perceived to be the cause of noncarious cervical lesions, and to ascertain their most frequent method of treatment.

METHODS

The survey was completed by 63% of the 343 dentists polled.

RESULTS

Ninety-four percent classified the lesion as abrasion, and 66% rated toothbrushing as the most likely cause. Treatment methods were varied, with no clear preference.

CONCLUSION

The most frequently used restorative materials were GI/composites (29%) and composites (27%). The results of the survey suggest that treatment provided for noncarious cervical lesions may not be based on the correct diagnosis.

Visualization of root caries lesions by means of a diazonium dye

A diazonium dye was used to visualize caries lesions in root tissue. Root caries lesions were created in vitro according to a variety of protocols based on methylcellulose gel (6% w/v) and/or lactic acid buffer (0.05 M, pH 4.5). Teeth containing lesions were soaked overnight in an alkaline solution of 2% (w/v) 2-naphthol or resorcinol, rinsed with distilled water, and immersed in a diazonium solution (prepared by titration of aniline with sodium nitrite in 1 M HCl at 5 degrees C) for up to 10 min, prior to being thoroughly rinsed with distilled water. The area of the caries lesion on the anatomical surface was clearly marked with a red/orange color following 5 minutes' incubation in the diazonium solution. The diazonium complex formed with 2-naphthol was found to be more resistant to leaching during rinsing and sectioning than that formed with resorcinol. Microscopic examination of sections taken in the apicalcoronal plane showed that the depth of area of the lesion was also marked by the red/orange coloration. Chemical changes in root mineral monitored during lesion formation showed some degree of correlation between lesion area and mineral dissolution. Visualization of coronal caries by this technique is currently under investigation. The visualization technique provides a simple means of determining the extent and severity of root caries lesions and may be a useful first step in their classification.

Root caries in the older patient: significance, prevention, and treatment

Root caries is an emerging challenge to the dental professions because of the growing number of increasingly aging adults who have retained many or all of their teeth. Risk factors for developing root caries point to both intraoral and environmental factors, making the management of root caries complex and multidisciplinary. Prevention based on a composite of risk factors is the most desirable approach for management. Patients who have developed caries of the roots can be treated with remineralization strategies, recontouring techniques, intracoronal restorations of a variety of established and recently introduced materials, or extracoronal restoration. Dental professionals need to keep abreast of new approaches that are emerging for the management of root caries.

Diagnostic tools and measurements--impact on appropriate care

The diagnosis of primary coronal caries should be seen as a complex process, comprising both detection and measurement phases, which enables clinicians, researchers and epidemiologists to make informed decisions about the management and prognosis of the disease process. The different diagnostic thresholds employed for measurements of caries experience can be viewed as an iceberg, a metaphor which demonstrates the ambiguity of the term "caries free" and which can also represent the differing management options appropriate for the care of different types of active and inactive lesions: NAC (No Active Care). PCA (Preventive Care Advised) and OCA (Operative Care Advised). There are considerable methodological difficulties in drawing valid comparisons between studies using incompatible criteria and simulations. However, it is apparent that no caries diagnostic tool in current clinical use fulfils all of the ideal criteria for measurements needed to plan and monitor appropriate care. Systems providing reliable serial measurements with which to assess future caries risk and present caries activity are urgently required as diagnostic tasks are becoming both more difficult and more important from the standpoint of long-term oral health. Existing diagnostic tools frequently rely on subjective judgements and provide only semi-quantitative measures insensitive to smaller lesions. In the future tools are needed which are objective, quantitative and which can provide acceptable compromises between sensitivity and specificity for a wide range of applications for individual patient care as well as for research and survey use. Key problem areas with existing tools include confusion in terminology and between caries assessments made by clinicians and epidemiologists as well as the lack of valid measurements relating to the activity of primary root caries and secondary caries. Deficiencies with current tools impact on the care of individuals by allowing false negative diagnoses of hidden occlusal dentine lesions and approximal cavities on the one hand, whilst generating some false positive diagnoses on sound surfaces leading to inappropriate decisions to restore on the other. At the population level, current conventional tools significantly underestimate overall caries experience. In future the adoption of more accurate and reliable methods would facilitate more effective preventive care and promote more appropriate restorative treatment decisions. Research in this area should focus for the next five years on diagnostic technologies which: 1) inform valid prospective caries risk assessments for different age groups, 2) can help to determine present caries activity and monitor lesion behaviour over time and 3) help identify methods which can implement existing and new research knowledge about diagnostic tools into clinical and research practice.

A fiber-optic setup for quantification of root surface demineralization

A fiber-optic fluorescence observation (FOFO) technique has been developed for the quantification of demineralized root dentin. The method was tested on 40 specimens of in vitro demineralized parts of human root dentin. Fluorescein sodium salt was used as a penetrating dye. The fluorescein sodium salt was excited using light around 465 nm. The fluorescence signal around 527 nm measured for demineralized dentin was corrected for lamp output and then divided by the corrected fluorescence signal for the sound control dentin on the same root, resulting in a FOFO-value. FOFO-values correlate linearly (r = 0.91) with mineral loss measured by transverse microradiography. Therefore, it was concluded that the FOFO-technique provides a good, non-destructive measure of the severeness of in vitro demineralized human root dentin, and is applicable on bulk dentin. Future work on natural lesions in vivo will be needed to investigate the applicability of the technique in a clinical situation.

The RCI revisited after 15 years: used, reinvented, modified, debated, and natural logged

OBJECTIVES

The purpose of this article is to review the status of the Root Caries Index (RCI) 15 years after it was first introduced in the dental literature as a method for the reporting of supragingival root lesions. This review focuses on the extent to which the RCI has been used by epidemiologic researchers, as well as on the issues concerning the RCI as a useful index that have been raised and debated in the literature by those epidemiologic researchers.

METHODS

The debated points are categorized into six issues, including whether: (1) the RCI underestimates the prevalence of root caries by omitting subgingival root caries lesions; (2) the RCI overestimates the prevalence of root caries by using too rigid a definition of when recession can be visualized; (3) the RCI makes the assumption that there is a linear relationship between root caries lesions and the occurrence of at-risk surfaces, i.e., surfaces with recession; (4) the RCI, by ignoring missing teeth, distorts the descriptive epidemiologic picture of root caries; (5) recession is a predictor of root caries versus merely being an antecedent state; and (6) the imprecision of diagnosing gingival recession renders the RCI useless.

RESULTS

Given both the evidence from recent studies and the professional interest in subgingival root caries, as addressed in the first debated point, it seems reasonable to modify the RCI to include a separate reporting of subgingival root caries. Of the remaining debated points over the past 15 years, three of these (points #2, #4, and #5 above) seemingly serve to clarify specific aspects of the RCI that were intended as inherent elements of the RCI as originally presented. The question as to whether there is an assumption of a linear relationship between root caries lesions and the occurrence of at-risk surfaces (point #3) is answered in the negative. The final debated point (#6), while addressing a fundamental periodontal tissue measurement issue--namely the reliability of identifying gingival recession--and while theoretically interesting, should not undermine the current use, or utility, of the RCI, but rather suggests the need for improved periodontal diagnostic techniques for the condition of recession.

CONCLUSIONS

After 15 years, the RCI appears to be one of the two most common methods of reporting root caries in the epidemiologic literature (along with DFS counts). In fact, the best overall descriptive picture of root caries is achieved when those two reporting methods are presented in the same study accompanied by descriptive presentations of missing teeth and at-risk surfaces. Of all the debated points in the literature, the suggested modification of including subgingival lesions in the RCI leads now to the recommendation to collect subgingival data, but to do so in a manner that allows for separate presentation of supra- and subgingival root caries findings.

Evaluation of sodium fluorescein for quantitative diagnosis of root caries

The diagnosis of root caries, in particular the judgment of the activity of a visually observed lesion, is difficult. Quantitative determination of lesion severity would allow the lesion to be monitored with time, so that an indication of lesion activity could be obtained. This paper describes a step in the development of a method that provides such a quantitative determination. Specifically, fluorescein sodium salt is used as a penetrating dye, the subject of study being the relationship between dye concentration and porosity in demineralized root dentin. Fourteen human third molars were demineralized in vitro (lactic acid CMC-gel, pH 5; in each of 6 groups for 4, 7, 11, 14, 18, and 21 days). Fluorescein sodium salt (0.2 g/L) was applied for 2 min. Thin slices (+/- 130 microns) were cut from the root surfaces without water cooling. The dye fluorescence radiance in the demineralized dentin was determined by means of a micro-Raman spectroscope and compared with the mineral loss profiles measured with transverse microradiography (TMR). The TMR data were corrected for the difference in measurement area between the two measurement systems. Corrected TMR profiles were compared with the corresponding fluorescence scans, showing linear correspondence. The correlation coefficient was r = 0.96. We conclude that, after uptake of fluorescein sodium salt for 2 min, the dye concentration in an artificially produced root-surface caries lesion is proportional to the amount of mineral lost from that lesion.

Reproducibility of clinical caries diagnoses on coronal and root surfaces

Intra- and interexaminer reproducibility of clinical caries diagnoses was studied using 3 experienced dentists, who independently examined 20 patients twice at an interval of 2-6 weeks. The lesions were classified as one of the following four diagnoses: (1) initial active caries, (2) initial inactive caries, (3) manifest active caries, and (4) manifest inactive caries. For the various diagnoses, signs of cavitation, surface structure and discolouration were used. The reproducibility at a patient level was evaluated using intraclass correlation coefficients and at a surface level using kappa statistics. At a patient level, for the total number of lesions, the intraclass coefficients of correlation varied from 0.55 to 0.77. For the individual diagnoses, total manifest caries showed the highest coefficients of correlation, ranging from 0.73 to 0.92. At a tooth surface level, the kappa values varied from 0.29 to 0.61. The most common shift was that from any type of caries diagnosis to a diagnosis of a sound surface. There was little difference between the results for coronal and root caries and between initial and manifest lesions. Nor was there any difference for buccal + lingual surfaces only compared to all surfaces. Judging from the pattern of change in diagnosis between the repeated examinations, the main source of error seemed to be due to the fact that the lesions observed at one examination were overlooked at the other examination.

A method for adjusting caries increments for reversals due to examiner misclassification

Two types of reversals occur in longitudinal caries studies, remineralization (true reversals) and reversals due to examiner misclassification (D3 to S; F to S). Since 1966, the standard practice has been to subtract examiner reversals from the crude increment (CCI), resulting in a net caries increment (NCI). The use of the NCI has been based on the assumption that examiners make an equal number of false positive and false negative errors both at baseline and follow-up examination. Consequently, the difference between the two caries prevalence scores would provide an unbiased estimate of caries incidence between examinations. The NCI considers all reversals to be true reversals which is an extreme strategy, particulary when the level of diagnosis is set at lower thresholds. In this study we compromised between the NCI and CCI by creating a simple formula to calculate the caries increment using a prevalence-based adjustment for reversals. The formula is ADJCI = y2(1-(y3/(y3 + y4))), where y2 = S to D or F; y3 = D or F to S; y4 = D to D/F or F to F. The impact of this adjustment is illustrated using data from a random sample of 452 older black and white adults followed over a 3-yr period. The ADJCI was more likely to result in higher caries increments and more observed intergroup differences than the NCI, a finding that has implications for clinical trials. For example, the crude 3-yr coronal DS increment for whites was 0.62, the NCI was 0.26 and the ADJCI was 0.56. There were significant black-white differences for the CCI and ADJCI, but not the NCI. We conclude that the NCI was too severe of an adjustment for reversals for this study population.

Root caries: prevention and chemotherapy

PURPOSE

Root caries is a problem of importance among dentate elderly. Greater life expectancies at both birth and age 65, combined with improvements in tooth retention across all age groups, have resulted in an increasing number of Americans who have retained their teeth into old age. This increase in numbers of teeth combined with the increase in the percent of teeth with recession has in turn resulted in older persons with more root surfaces at risk for caries than ever before. The purpose of this article is to review the literature on the prevention and chemotherapeutic approach to root caries.

METHODS

A review of the literature and synthesis of this information resulted in recommendations for the improved root caries risk assessment and the development of clinical examination protocols and strategies for prevention and treatment.

RESULTS

Clinicians can better identify persons at risk for root caries in their practice. People who are older, have moderate to severe periodontal bone loss and gingival recession, are impaired, have poor oral hygiene, take multiple medications, have partials, have retained root tips and the recently unemployed or retired are all at increased risk for root caries. Examination strategies should include the use of at least annual bite-wing radiographs (vertical bite-wings in persons with significant attachment loss) and careful examination of the proximal tooth surfaces. Once identified as low, moderate or high risk, daily and professionally applied fluoride therapies should be combined with dietary modifications, and in high risk individuals, antimicrobial agents for both the remineralization of early lesions and prevention of further root caries.

Examiner agreement on caries detection and plaque accumulation during dental surveys of elders

Indices used to evaluate plaque accumulation and coronal caries have been widely accepted in epidemiological studies, yet their reliability cannot be guaranteed. The aim of this study was to evaluate the reliability of clinical criteria used in coronal and root caries diagnosis and oral hygiene evaluation as applied in elders. Nineteen elderly subjects, 73 years old on average, were examined at a first appointment by two independent examiners. They were re-examined two weeks later. Plaque accumulation was evaluated using the Plaque Index (PI) and coronal and root caries were detected according to the WHO criteria and Fejerskov et al. (1991), respectively. Recurrent caries was recorded as recommended by WHO and by probing at the interface tooth-restoration. Inter- and intra-examiner agreement was evaluated using kappa statistics. The PI score showed good reliability except for examiner b, for whom a simplification of the 4-point scale in 3-point scale improved significantly the reliability. The prevalence of coronal caries was very low and intra- and inter-examiner agreement was poor. Most of the root caries lesions were covered by plaque and the kappa values indicated only poor agreement. Recurrent caries were found with good agreement using WHO criteria but the detection with the probe was not reliable. In conclusion, it seems that examiners should be trained carefully to maximise their reliability and that plaque should be removed to obtain reliable diagnoses of caries. Retraining and calibration may be necessary for surveys continuing over a long period.

Root resorption associated with hydroxyapatite particles: a case report

A case report of an unusual root resorption reaction associated with a graft of hydroxyapatite particles is presented. The hydroxyapatite particles were grafted to treat vertical infrabony defects at the distal aspect of the maxillary left canine and on the mesial side of the mandibular right first molar. The graft sites were monitored at maintenance visits. Root resorption was observed radiographically 9 to 10 months after grafting. The lesions were restored with a light-cured glass-ionomer cement and/or a resin composite. Possible etiologic factors associated with this condition are discussed.

Multifactorial modeling for root caries prediction: 3-year follow-up results

The study was part of a series aiming at the development of caries tests. The initial material (n = 104, age range 47-79 yr, mean 62 yr) was reduced to 96, who were observed for 3 yr. During the follow-up four subjects died, all due to myocardial infarction, and four refused to participate. Thorough oral examinations were conducted at the baseline, 1- and 3-yr registrations; coronal and root surface caries were registered separately according to WHO classification. The tests included salivary mutans streptococci, lactobacilli, candida/yeasts, secretion rate, buffer effect and sucrase activity, and quantitation of visible plaque. The association between prospective root caries increment and several tests was significant. Multifactorial modeling resulted in the combination of Past Root Caries Experience (OR 12.8), Lactobacilli (OR 8.6) and Candida (OR 2.8). At screening, the criterion "two or three positive tests" of these yielded acceptable accuracy (77.1) and a relative risk of 3.3.

A comparison of primary root caries lesions classified according to colour

Three hundred and ninety-five primary root caries lesions in 117 patients were included in this study. Each lesion was clinically characterised (colour, dimensions, distance from gingival margin and texture) and a sample of infected or altered dentine was taken using a standardised sampling procedure. The relationships between the colour and the microflora, texture, physical dimensions and distance from the gingival margin of the lesions were investigated. Lesions in each colour group (light brown, yellow, dark brown and black) were identified in each texture category (soft, leathery and hard), except for black lesions which were recorded as only soft or leathery. Black soft and black leathery lesions had a significantly greater area and harboured more lactobacilli than all other types of lesions while black leathery lesions also harboured significantly more yeasts. There were no significant differences in the number of bacteria or mutans streptococci isolated from soft or leathery lesions irrespective of lesion colour. Overall, these data indicate that the colour of primary root caries lesions is not a reliable indicator of primary root caries activity. Assessment of the clinical severity of primary root caries lesions requires consideration of lesion texture and the distance of the lesion from the gingival margin rather than the colour of the lesion.

Relationships between yeasts and primary root-caries lesions

A total of 447 primary root-caries lesions from 169 dental patients was studied to determine the relationships between their clinical severity and the number and frequency of isolation of yeasts. Yeasts were isolated more frequently from soft lesions, from lesions at the gingival margin and from lesions deemed to require restoration. These associations may be due to the aciduricity and acido- genicity of yeasts but the relatively low numbers found do not support a pathogenic role for yeasts in the aetiology of root caries: at best they may be marker organisms of the most severe disease.

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.

Epidemiology of root caries

Many epidemiological studies have been conducted on a variety of populations. Unfortunately, comparison of the prevalence data, and to a lesser degree of the incidence data, between the various studies is of little use due to the lack of standardised diagnostic criteria, reporting methods and population diversity. In the few incidence studies which have been conducted around 30-40% of people developed root caries, although many adults in the population appear to have been affected by root caries. Many risk factors associated with the occurrence of root caries have been identified and these include oral, medical, mental, behavioural and psychosocial conditions.

Relationships between mutans streptococci and perceived treatment need of primary root-caries lesions

A total of 447 primary root-caries lesions from 169 dental patients was studied to determine the relationships between mutans streptococci and the perceived treatment need of primary root-caries lesions. Samples of this altered dentine for microbiological culture were obtained. Lesions were classified into 5 treatment categories: soft and restore, leathery and restore, leathery and debride of caries, leathery and treat chemotherapeutically, and hard, to receive no treatment. The total numbers of mutans streptococci decreased significantly with decreased treatment need. The percentage of mutans streptococci from lesions requiring no treatment was significantly less than from lesions requiring treatment. The frequency of isolation of mutans streptococci was significantly greater from lesions requiring more treatment. Significantly more lesions containing > 10(2) mutans streptococci were distributed in the groups with a greater perceived treatment need or with larger dimensions occluso-gingivally and/or mesio-distally or bucco-lingually or with a closer proximity to the gingival margin.

Root caries: some clinical aspects

This paper has discussed some aspects of root surface caries which are of special relevance to the clinician. Epidemiological studies have suggested that root caries is not inevitable after gingival recession, but a small number of patients show a propensity for development of new lesions. Several risk factors have been identified. Thorough prophylaxis is essential for accurate diagnosis of root caries lesions, and radiographs can identify lesions which would otherwise be difficult to detect. The activity of any particular lesion can only be evaluated by observation at successive examinations. Fluoridated water may have a role in the prevention of root caries, but the evidence is not conclusive. Other forms of topical fluoride have been demonstrated to be effective. Cleansable and accessible lesions can be arrested with good oral hygiene and topical fluoride therapy. Teeth which require restoration may be restored with GIC, but limitations of the material make this unsuitable for all but readily accessible lesions, or where margins are supragingival. Clinicians should not rely on the fluoride released from GIC in situations where another material may provide a better restoration; in many situations, amalgam may be the material of choice. The longevity of bonded amalgam restorations has not been established, and conventional methods of amalgam retention remain a requirement of every restoration.