Maximizing the Benefits of Sealants

With their introduction in 1971, dental sealants have become a preventive tool in dental care programs among practicing oral health clinicians in the United States and abroad.¹ Pit and fissure sealants are defined as “a material that is introduced into the occlusal pits and fissures of caries-susceptible teeth, thus forming a micro-mechanically bonded, protective layer cutting access of caries-producing bacteria from their sources of nutrients.”² Before placing dental sealants, risk assessment, caries detection, and proper diagnosis are essential components to ensuring that the maximum benefits of sealants are attained.

Properly employed sealants provide an excellent means of preventing or controlling early dental caries, although a review by Mejare et al³ indicates further research is essential to determine their true benefit. A new visual examination methodology identified as the International Caries Detection and Assessment System (ICDAS) is currently being developed to assess caries activity. At present, clinicians have no reliable means to evaluate the activity of lesions. The ability to accurately assess whether a lesion is static, advancing, or regressing is paramount in determining the required course of treatment.

RISK ASSESSMENT

While great strides have been made in improving the oral health of American children, dental caries continues to be the most common disease of childhood, especially in pre-school children with lower economic standing. ⁴ Similarly, as more adults retain their dentition into their later years, coronal and root caries have become more of a health concern. Therefore, an initial risk assessment performed early in life and then repeated periodically into adulthood to identify those who are at greatest risk for the development of dental caries is imperative. While the factors that initiate caries in a young child may differ from those that initiate disease in an adult, the need for periodic systematic assessments in all dental patients cannot be overly emphasized. Risk assessment must be considered a necessary component in the clinical decision making rocess. ^5,6

The etiology of the dental caries process involves a combination of factors including diet, a susceptible host, and microflora, which interplay with a variety of social, cultural, and behavioral factors. Thus, a detailed analysis of all of these factors together with the exposure to protective factors, eg, fluorides, past history of dental caries, and current presence of active disease, are necessary components of risk assessment and help determine the most appropriate treatment plan for a particular patient.⁶ For example, a detailed assessment of the diet is necessary to identify the amount, forms, and frequency of ingested fermentable carbohydrates in order to offer solutions tailored to a patient’s needs. In addition, caries risk indicators are useful in the clinical management of dental caries because they help determine if additional diagnostic procedures are required. These may include measurement of salivary flow and buffering capacity or microbial analyses to quantify the concentration of cariogenic bacteria present in dental plaque. Risk assessment can also identify those who may require additional caries control measures, assess the success of these measures over time, guide treatment planning decisions, and determine the timing of recall appointments and frequency of risk assessments.

Recently, Zero et al⁷ concluded in a systematic review that previous caries experience is the best indicator for the development of future disease in primary teeth, followed by level of parental education and socioeconomic status. For permanent teeth in children and adolescents, clinical predictors (decayed, missing, and filled surfaces; predicted caries by the clinician; and pit and fissure morphology) were the most important indicators. For permanent teeth in adults, factors such as education and marital status had a significant impact on caries experience because they may influence attitudes toward oral health. Also the baseline number of teeth and the mean periodontal attachment loss were also thought to predict the number of tooth surfaces at risk for decay in the future. Most of the studies did not report that the presence of non-cavitated lesions was important, although their presence has predictive value.

The development of technology to detect and quantify early caries and to directly assess lesion status (active vs inactive) would be greatly beneficial in identifying patients who require intensive preventive intervention. At present, a number of technologies are being explored to determine their potential to detect caries at early stages and to monitor caries over time. These include electro-con-ductivity, laser fluorescence, and trans-illumination. While some marketed products have incorporated these technologies, industry continues to refine and improve on the capabilities of these instruments.⁸

THE CHANGING CARIES PROCESS

The ability to determine caries status and activity using only a single point of observation is extremely difficult. First, caries is an infectious, transmissible, multifactorial disease of bacterial origin.^5,9 It is initiated at the subclinical level and is a dynamic process resulting in progression, stabilization, or even regression of a lesion, based on the equilibrium of the remineralization-demineralization cycle.⁹ Besides reducing the overall prevalence of dental caries in adults and children, the availability of fluoride in water supplies and dental products has also resulted in a dramatic increase in the time needed for carious lesions to progress from early demineralization to frank cavitation.¹⁰ Prior to the introduction and wide availability of fluoride, caries was likely to progress rapidly and dental practitioners were inclined to restore rather than monitor suspicious or questionable surfaces.

Seeking to lower the threshold of detection from frank cavitation to the detection of smaller precavitated lesions, determining caries activity has been tremendously difficult for clinicians to understand and accept. This is because, until recently, they have been dealing with an outcome that did not change: cavitation. With a higher threshold, when caries is considered to be present only at the point of cavitation, most lesions are self-propagating. When the threshold of the disease process is lowered to a point prior to cavitation, such as the development of a white spot lesion, an understanding of how the disease process is assessed or described at these earlier stages must occur as well.

VISUAL EXAMINATION FOR CARIES DETECTION

The traditional method of occlusal caries detection has been the visual-tactile examination. The visual-tactile examination has the advantages of being quick and inexpensive; only needing a sharp eye and sharp explorer to perform. Over time and with the changing caries process, the raditional visual-tactile examination has developed a number of distinct shortcomings. Primarily, clinicians are forced to measure a dynamic process as a divisive variable of presence or absence of disease. ¹¹ In addition, the visual-tactile examination does not allow quantification of lesions. Therefore, following changes in the lesion over time, which is crucial to determining activity, is difficult. Many researchers believe that understanding the caries process has progressed far beyond the point of

restricting the evidence for dental caries at the D2 (caries in enamel only) or D3 (caries in enamel and dentin) levels of cavitation. Recording lesions only at the cavitation level is no longer acceptable.¹²

In addition, the common clinical criteria, ie, color, softness, resistance to removal, etc, are all rather subjective. Similarly the tools (sharp explorer and dental radiographs), which in the period when caries prevalence was high were adequate, are now less useful. ¹¹ The use of sharp explorers offers no advantage to a visual examination if the examination is performed on clean and dry teeth. Traditional probing with a sharp explorer has come into question as the ultimate determinant of caries activity. The exclusive use of a “catch”by the sharp explorer to diagnose caries in pit and fissure sites should be discontinued. Non-cavitated lesions can become cavitated simply through pressure from the explorer during the typical examination. Thus, penetration by a sharp explorer can actually cause cavitation in areas that are remineralizing or could be emineralized. An explorer can also transfer cariogenic bacteria from one tooth surface to another.⁶ Clearly, the development of more refined diagnostic tools that can measure the smaller changes seen in early dental caries would allow earlier preventative intervention and shift the emphasis in dentistry away from restoration and more toward conservation of tooth structure.^10,13

In an effort to address the changes in the caries process and to negate the disadvantages of the traditional visual-tactile examination, new diagnostic criteria are needed.^14,15 An international effort is currently developing and refining the International Caries Detection and Assessment System or ICDAS.^16-18 The purpose of this index is to collect all data on the previous indices and combine them into a system that can be used for epidemiological and public health issues, clinical research, and clinical practice, depending on the criteria selected. This system is meant to be a unifying, predominantly visual, criteria code to allow detection and monitoring of severity and activity of early incipient and advanced lesions on occlusal, approximal, and smooth surfaces even after a single observation. These criteria codes have been validated histologically and correlate with the severity of lesions in teeth that have been examined in vitro and then sectioned.

Clinically, each examined tooth is thoroughly cleaned and dried to ensure the removal of all surface debris. Each surface type (occlusal, approximal, and facial/lingual) is examined and coded for presence or absence of a lesion following air-drying for a minimum of 5 seconds (Table 1). If no changes on the surface are noted following drying, then the surface is scored as a zero (sound). If changes are noted then these are coded as a 1,2,3,4,5,or 6 based on the severity criteria. Aseparate set of criteria are then used to describe the activity of the lesion again using a 1,2, or 3 as a scoring code (Table 2). Investigations to further refine the criteria are being conducted. Preliminary data from on- going and recently completed studies indicate that the ICDAS is repeatable¹⁹ and it has good sensitivity and specificity when compared to polarized light microscopy.²⁰

CONCLUSION

Prior to the placement of a dental sealant, the clinician must be able to not only detect evidence of dental caries but also diagnose the presence (activity) and risk of disease. Detection is the knowledge that there is a defect, but detection does not tell a clinician whether the defect has developed recently or many years previously. Diagnosis, on the other hand, must include an assessment of risk that determines the importance of various host factors such as salivary flow and composition, diet, plaque, and medical, social, behavioral, and psychological factors to determine their possible impact on the presence or absence of current and future disease. Diagnosis must incorporate reliable criteria to allow the clinician to determine if the defect is active and if it requires surgical or non-surgical intervention to arrest or reverse. While we have focused on discussing caries activity’s role in diagnosis and risk assessment and how risk assessment is an essential component in the treatment decision making process, the same applies to any other treatment planning decision, including, the need for restoration (type of material, cavity design, etc), fluoride use (type of fluoride, number of applications, frequency of applications, etc), or chlorhexidine use (frequency of application, etc).

While frequently used interchangeably, detection and diagnosis are two completely different entities. Disease is not diagnosed by detecting the lesions. Periodic and thorough risk assessment and an understanding of the changing caries process are required if dental sealants are to be used to prevent initiation of dental caries or even control the progression of active incipient disease.

REFERENCES

1. Adair SM. The role of sealants in caries prevention programs. J Calif Dent Assoc. 2003;3: 221-227.
2. Simonsen R. Pit and fissure sealants: review of the literature. Pediatr Dent. 2002;24: 393-414.
3. Mejàre I, Lingström P, Petersson LG, et al. Caries-preventive effects of fissure sealants: a systematic review. Acta Odontol Scand. 2003;61:321-330.
4. Tinanoff N, Kanellis M, Vargas CM. Current understanding of the epidemiology mechanisms, and prevention of dental caries in preschool children. Pediatr Dent. 2002;24:543-551.
5. Barber LR, Wilkins EM. Evidence-based prevention, management, and monitoring of dental caries. J Dent Hyg. 2002;76:270-275.
6. American Dental Association. Treating caries as an infectious disease. J Amer Dent Assoc. 1995;126:2-8-15-8.
7. Zero D, Fontana M, Lennon AM. Clinical applications and outcomes of using indicators of risk in caries management. J Dent Educ. 2001; 65:1126-1132.
8. Pitts NB, Stamm JW. International Consensus Workshop on Caries Clinical Trials (ICW-CCT)—final consensus statements: agreeing where the evidence leads. J Dent Res. 2004;83(special issue):C125-C128.
9. Zero DT. Dental caries process. Dent Clin North Am. 1999;43:635-663.
10. Angmar-Mansson B, al-Khateeb S, Tranaeus S. Monitoring the caries process. Optical methods for clinical diagnosis and quantification of enamel caries. Eur J Oral Sci. 1996;104: 480-485.
11. Dodds M. Dilemmas in caries diagnosis—applications to current practice and need for research. J Dent Educ. 1993;57:433-438.
12. Pitts N, Stamm J. Caries research implications of the international collaborative workshop on caries clinical trials (abstract). Caries Res. 2002; 36:208. Abstract 106.
13. Bader JD, Shugars DA. Need for change in standards of caries diagnosis- epidemiology and health services research perspective. J Dent Educ.1993;57:415-421.
14. Ekstrand KR, Ricketts DN, Kidd EA, Qvist V, Schou S. Detection, diagnosing, monitoring and logical treatment of occlusal caries in relation to lesion activity and severity: an in vivo examination with histological validation. Caries Res. 1998; 32:247-254.
15. Nyvad B, Machiulskiene V, Baelum V. Reliability of a new caries diagnostic system differentiating between active and inactive caries lesions. Caries Res. 1999;33:252-260.
16. Pitts N. Review of the ICW-CCT meeting, the importance of early caries detection, and the philosophy and approach of ICDAS. In: Stookey GK, ed. Early Detection of Dental Caries III: Proceedings of the 7th Indiana Conference. Indianapolis: Indiana University. In press.
17. Ismail A. ICDAS: International caries detection and assessment system. The Michigan study and other work in progress. In: Stookey GK, ed. Early Detection of Dental Caries III: Proceedings of the 7th Indiana Conference. Indianapolis: Indiana University. In press.
18. Pitts N. “ICDAS”—an international system for caries detection and assessment to facilitate caries epidemiology, research and appropriate clinical management. Community Dent Health. 2004:21:131-136.
19. Eggertsson H, Ferreira Zandona AG, Jackson R, et al. New visual caries detection criteria in clinical studies. Abstract 2809. Available at: http://iadr.confex.com/iadr/2004Hawaii/techprogram/abstract_47347.htm. Accessed January 18, 2005.
20. Ferreira Zandona A, Ando M, Eggertsson H, et al. Clinical validation of caries detection methodologies: preliminary results. Abstract 2812. Available at: http://iadr.confex.com/iadr/2004Hawaii/techprogram/abstract_45471.htm. Accessed January 18, 2005.

From Dimensions of Dental Hygiene. February 2005;3(2):16, 18, 20-21.