Jane A. Weintraub, D.D.S., M.P.H.:
In 1983 the National Institutes of Health hosted a consensus development conference on dental sealants in the prevention of tooth decay (NIH, 1984). The panel�s conclusion was that the "placement of sealants is a highly effective means of preventing pit and fissure caries." The panel said that sealants were 100 percent effective in pits and fissures that remained completely sealed, although sealant retention declines over time. Since then, there have been comprehensive reviews (Weintraub, 1989; Ripa, 1985, 1993) and a meta-analysis (Llodra, Bravo, Delgado-Rodriguez, et al., 1993) that confirmed the effectiveness of sealants and a workshop that developed guidelines for their use (Siegal, Kumar, 1995). Sealants are still needed, since 78 percent of 17-year-olds in the United States have experienced dental caries (Surgeon General, 2000), and most of the disease occurs in pits and fissures (Kaste, Selwitz, Oldakowski, et al., 1996). Sealants, however, are far from being universally applied. In 1988-94, only 23 percent of U.S. 8-year-old children and 15 percent of 14-year-old children had received sealants (U.S. DHHS, Healthy People 2010). The current charge is to examine the evidence demonstrating the effectiveness of sealants in high risk children and to discuss the findings of the Research Triangle Institute/University of North Carolina group.
The RTI/UNC group used four initial criteria to select caries management studies: (1) studies of methods applied or prescribed in a professional setting (or professional provision); (2) in vivo studies; (3) studies with a concurrent comparison group; and (4) studies using traditional outcome measures of caries experience. For studies of the management of noncavitated lesions they included studies where the lesion was the unit of analysis. For studies on the management of caries in high-risk individuals, the risk determination was "made on an individual subject level based on carious lesion experience and/or bacteriologic testing." In other words, high-risk status conferred by group membership, such as a school or community with a high caries rate or low socioeconomic status, was not sufficient.
Because of these restrictive criteria, the investigators found only one study (Heller, 1995) that met the criteria and examined sealant use in noncavitated lesions, and only two studies that met the criteria and used sealants alone (Sheykholeslam, Houpt, 1978) or sealants in combination with other preventive agents in high-risk individuals (Zickert, Emilson, Krasse, 1982). Another sealant study was listed in the references but is not found in the tables (Carlsson, Petersson, Twetman, 1997).
This presentation will describe the RTI/UNC criteria, as well as those four studies and their limitations, in more detail. Additional studies are also discussed to better reflect the nature of sealant studies and include the studies that appear in this abstract�s tables 1 and 2.
Many of the first trials of sealants used a half-mouth design where children with one or two pairs of sound, homologous molars were included. Sealant was applied to one randomly selected molar while its pair was left unsealed. Most of those trials did not specifically discuss caries risk status, but review indicates that some of them specifically selected children with prior caries experience (Buonocore, 1970, 1971; Brooks, Mertz-Fairhurst, Della-Giustina, et al., 1976; Mertz-Fairhurst, Fairhurst, Williams, et al., 1984; Sheykholeslam, Houpt, 1978; Houpt, Shey, 1983; McCune, Bojannini, Abodeely, et al., 1979), either in general or specifically first permanent molars. In the latter case, studies such as those by Rock, Gordon, and Bradnock (1978) and Rock and Evans (1982) required all four first permanent molars to be erupted and caries-free in 6-7 and 8-year-olds, respectively. Thus, these children might have been at lower caries risk than children who did not have all four molars caries-free (McCune, Horowitz, Heifetz, et al., 1973; Weintraub, Stearns, Burt, et al., 1993.)
Other studies with a half-mouth design included children with one or two pairs of sound, homologous, first permanent molars. The proportion of children contributing only one pair may be indicative of at least one member of the other pair being unerupted or (more likely) carious, depending on the age of the child. The proportions of pairs of caries-free teeth available may have been a surrogate measure of the child�s caries status, indirectly correlated with caries experience and caries risk. These studies likely included a mix of low- and high-risk children. The current effectiveness of sealants is underestimated because the first generation of material used, polymerized by ultraviolet light, was less effective than newer materials and is no longer in use (Ripa, 1993). The retention rate in any sealant trial is also dependent on the accuracy with which examiners can identify the presence of sealant. Misclassification occurs more often when a clear resin rather than an opaque resin is used (Rock, Potts, Marchment, et al., 1989).
Caries risk can be considered at the personal level or at the tooth level. Some studies have compared sealants on carious vs. noncarious teeth (Leverett, Brenner, Handelman, et al., 1983), or on sound surfaces vs. surfaces with incipient lesions (Heller, Reed, Bruner, et al., 1995). In 1991, Handelman reviewed radiographic and bacteriologic studies investigating the therapeutic use of sealants and concluded that "caries is inhibited and may in fact regress under intact sealants." Some (Weerheijm, Groenn, Bast, et al., 1992) have expressed concern about occlusal radiolucencies beneath sealed surfaces. In retrospective sealant studies, dentists may or may not have selected high-risk children for sealant placement, but sealed and unsealed teeth can be compared in children, based on their prior caries experience as a measure of their caries risk status (Weintraub, Stearns, Rozier, et al., In press.) Recent attempts to target high-risk children have compared sealant survival rates (Kumar, Cavila, Green, et al., 1997), caries reduction (Carlsson, Petersson, Twetman, et al., 1997), or reduction of S. mutans levels (Mass, Eli, Lev-Dor-Samovici, et al., 1999) in teeth sealed in high-risk children compared to unsealed or sealed teeth in low-risk children.
Table 1. Pit and fissure sealants in high risk children: half-mouth study design
First Author |
Year |
Type of Sealant |
N at Start |
Age at start |
Caries Risk |
Follow-up |
Full Retention (at final exam) |
Effectiveness |
Buonocore |
1970 |
UV-light |
60 |
4-15 |
Caries-free individuals with well coalesced occlusal surfaces excluded |
2 |
87% |
99%–permanent teeth |
McCune |
1973 |
UV-light |
128 |
K, 1st, |
Sealant placed on paired and unpaired teeth (usually homologue had already decayed) |
5 |
42% |
30%–younger group |
Brooks |
1976 |
Nuva-Seal Delton |
385 |
6-8 |
Caries-free children excluded (about 48% of those screened) 79% of possible first perm molar pairs treated |
7 |
31%–NuvaSeal, |
12% NuvaSeal, |
Houpt |
1978, |
Delton |
205 |
6-10 |
Evidence of caries and a pair of caries-free homologous first perm molars (21% screened were eligible) |
6 |
58% |
56% |
Charbeneau |
1977, |
Kerr, Chem-cured |
143 |
5-8 |
81% of possible first perm molar pairs included |
4 |
52.4% |
53.4% |
McCune |
1979 |
Delton |
200 |
6-8 |
At least one carious tooth |
3 |
87% |
85% |
Thylstrup |
1976, |
Concise |
217 |
7 |
40% one first perm molar pair, 60% two pairs |
2 |
60% |
98%–full |
Richardson Gibson |
1980, |
Chem-cure, pink colored |
266 |
2nd grade |
80% of eligible molars, teeth sealed if sound or "sticky" |
5 |
67.4% |
51.2% |
Vrbirc |
1983, 1986 |
Contact Seal |
244 |
6.8 |
76% of possible first perm molar pairs |
5 |
52% |
55% |
Table 2.Pit and fissure sealants in high risk children: other study designs
First Author |
Date |
Study Design |
Control/ |
Type of Sealant |
N at Start |
Age at Start |
Follow-Up Years |
Caries Risk Determination |
Outcome |
Conclusions |
Leverett |
1983 |
Half-mouth, benefit/cost analysis |
Sealants on one side, restorative care on other |
Nuva-Seal |
292 |
6-9 |
4 |
Caries-active (sealants placed on a carious surface) Caries-inactive (sealant placed on sound surface) |
1 year retention–52%, resealed; After 4 years, sealed surfaces 74% less caries increment than unsealed
|
Benefit cost ratios based on time or costs were more favorable for caries-active. Sealants should not be used unless evidence of past or current caries experience |
Weintraub |
1993 |
Retrospective cohort, patient records, Life table analysis, cost-effectiveness |
Children with none, any or 4 molars sealants; children with and without prior restorations |
Varied |
275 |
7.4 |
5.8–mean |
Restorations on first molars prior to sealant placement on remaining molars |
8-year survival: sealed teeth with and without prior restorations–85%, 94%; unsealed teeth–23% and 46% |
Cost savings from sealants were obtained within 4-6 years for children with prior restorations; after 8 years without prior restorations |
Heller |
1995 |
Retrospective cohort study, patient health center records |
96 children with and 17 without sealants, sealed and unsealed teeth |
Delton |
113 |
1st grade |
5 |
Tooth surfaces rated sound, "incipient", or frank caries |
Decay rates for initially sound sealed and non-sealed surfaces were 0.81 and 0.125 (OR=1.63); for initially incipient surfaces, .108 and .518 (OR=8.88) |
Initially sound teeth were unlikely to become carious in 5 years; sealants more effective in preventing further caries on surfaces initially with incipient lesions |
Kumar |
1997 |
Survival analysis |
Sealed high- risk first molars (65% sites) compared to unsealed low-risk first molars (35% sites) |
Helioseal, Delton |
1,122 |
7-9 |
4 |
Eligibility required prior caries experience. Teeth with shallow anatomy, occlusal or proximal D or F excluded |
Retention (with some resealing)–65-82%; Time to restoration or caries similar for both groups. Cumulative survival rate for 4 years: .89-.94 |
Targeting approach was effective |
Table 2. Pit and fissure sealants in high risk children: other study designs (continued)
First Author |
Date |
Study Design |
Control/ |
Type of Sealant |
N at Start |
Age at Start |
Follow-Up Years |
Caries Risk Determination |
Outcome |
Conclusions |
Carlsson |
1997 |
Prospective study, tx based on caries risk assessment, radiographs used |
High-risk children (121) received sealant, low risk did not (83) |
Helioseal-F (fluoride) |
204 |
6-7 |
2 |
Risk based on salivary mutans streptococci, lactobacilli, buffer capacity, past caries experience, cariogenic diet |
76.6% complete sealant retention, First molar DFS and dfs incidence lower for sealed group, but NS, enamel caries incidence sig diff in both dentitions |
Two-year caries incidence was 11-70% lower in high risk sealed group (range based on dentition and outcome measure) |
Maas |
1998 |
Prospective study of two groups receiving sealants; sealant delayed 3 months on one side |
Group 1 — mean deft =2.40 (low risk), Group 2 — mean deft = 6.60 (high risk) |
Helioseal |
52 |
6-8 |
0.5 |
Initially, deft "microbial replica" measured occlusal S. mutans |
For both groups, S. mutans was significantly reduced immediately after sealing and lasted up to six months |
Sealants reduced bacterial levels for both low-and high-risk groups |
Weintraub |
In press |
Retrospective cohort, Medicaid claims, discrete time hazard model |
Sealed and unsealed teeth |
Dentists’ choice |
15,438 |
4-7 |
8 |
Low risk --no prior Caries-Related Service involving Occlusal surface (CRSO) Middle risk— 1 prior CRSO, High risk > 2 prior CRSO |
Unsealed molars 3x more likely to get CRSO than sealed molars. Low risk —sealants effective up to 4 years, middle risk — lower odds for 6 years; high risk — reductions up to 7 years |
Medicaid expenditure savings for high-risk children within 2 years; not for low risk. |
Conclusions
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