modern thoughts on fissure sealants

370 Dental Update – October 2000

P A E D I A T R I C D E N T I S T R Y

Abstract: It has long been known that fissure sealants are an important part of theprevention and control of dental caries in pits and fissures. However, their usage is stillsporadic and generally not related to evidence-based guidelines. Caries prevalence haschanged since sealants were introduced and this has significant implications for the criteria onwhich to select patients who would most benefit from their usage. The clinical technique forsuccessful fissure sealant application is very moisture and operator sensitive. However, thereis accumulating evidence that use of fissue sealants can be extended, given suitableinvestigation, to the early carious lesion as a �preventive resin restoration�.

Dent Update 2000; 27: 370-374

Clinical Relevance: Prevention of dental caries is still of major importance in PaediatricDentistry. However, it is essential that children who are most susceptible to, or most at riskfrom, the consequences of dental caries are targeted. Fissure sealants are a highly successfuland very cost effective part of a preventive programme, if used in the right clinicalcircumstances.


Linda Shaw, PhD, FDS RCS, BDS(Hons), LDSRCS, Senior Lecturer and Honorary Consultantin Paediatric Dentistry, The University ofBirmingham Dental School, St ChadsQueensway, Birmingham B4 6NN.

WHO USES FISSURESEALANTS?The concept of sealing fissures and pitswas first suggested in 1967 by Cuetoand Buonocore.1 The development ofthe bis glycidyl methacrylate resin andclinical trials of its use took some timebut fissure sealants have now beenavailable in clinical practice for wellover 20 years. This certainly does notmean that they have been widely usedacross all developed countries with goodaccess to clinical services - there is arather patchy uptake (see Table 1). Inthe USA the 1986 to 1987 NationalHealth Survey showed a disappointinguse of occlusal sealants in children aged5 to 17 years of age.2 However, there is

more recent information to show thattheir use is increasing in the USA and inthe UK and Germany.3 Interestingly, itwas shown from the UK Child DentalHealth Survey (1994) that more fissuresealants were applied in Scotland than inthe rest of the UK, but this may berelated to several factors, includingcaries prevalence, which will beconsidered later in this article.4 In thepast, because fissure sealants were notpart of the �fee per item of Service�under the NHS, there have beensuggestions that fissure sealants wereprobably applied more to the teeth ofchildren whose parents could afford topay privately rather than to children whoactually needed them. The �capitation�scheme that was introduced was anattempt to put a much greater emphasison preventive care for children. In themore recent assessment of capitation inthe General Dental Service, an increasein the numbers of fissure sealantsapplied in regularly attending children

and adolescents was found.3

WHY SHOULD WE USEFISSURE SEALANTS?The efficacy of fissure sealants inpreventing dental caries in both pits andfissures has been shown in many clinicaltrials. There have been comprehensiveliterature reviews considering use,retention and effectiveness in preventingcaries and the clinical guidelines of theAmerican Academy of PaediatricDentistry (1998) specifically state thatsealants play a significant role in theprevention and control of dental caries.�They are intended to protect cariessusceptible tooth surfaces which arebenefited least by fluoride�. However,their clinical effectiveness is only part ofthe equation. Most published studies donot consider cost-effectiveness, costbenefit or cost utility of the procedures.It is almost impossible to quantify inrealistic human or child terms (not that

Modern Thoughts on FissureSealants

LINDA SHAW

● Usage generally low and unevenlydistributed across developed countries.● Recent evidence for increased use inUK, USA and Germany.● Affected by dental school training –those attending preventively orientatedschools used more fissure sealants.● In USA and Australia there was agreater use by practitioners whoseknowledge base was greater.● Greater use by dentists involved incontinuing education.● Low usage by practitioners concernedabout sealing in caries.● Low usage by those concerned aboutcost-effectiveness and decreasing cariesincidence.

Table 1: Sealant Usage.


Dental Update – October 2000 371

children aren�t human!) the savings indiscomfort from having a sealant placedrather than a restoration. Havingundertaken �random� surveys for years onpeople who have had both procedurescarried out, there has not been one whopreferred having a filling! Fissuresealants are also an extremely good wayof introducing a child to operative careand acclimatizing them to dentistry ingeneral. The realistic financial value ofthis is impossible to quantify. A criticalreview of methods for the economicevaluation of fissure sealants waspublished by Lewis and Morgan (1994)5

and this revealed a number of problemswithin studies. Economic evaluation of aprocedure may improve the quality andconsistency of decision making indentistry and will remain an importantconsideration, however, from an ethicalstandpoint, the protection of oral healthand freedom from disease cannot beassessed purely in economic terms.

Restorations themselves are also not apermanent solution when preventiveregimens have failed. They have to bereplaced with alarming and monotonousregularity and cost benefit analyses arefraught with difficulty. The relative costof different restorations in the UK wasassessed by Mjor, Burke and Wilson(1997)6 who reported a median longevityof 7 years for amalgam, 3.75 years forcomposite and 4.75 years for glassionomer restorations. The problem withthe restoration/re-restoration sequence isnot just cost but destruction of tooth

tissue, sometimes referred to as �thecountdown� of a tooth, and the �molarlife cycle�.

After an exhaustive search through thepublished literature, including a meta-analysis of factors influencing theeffectiveness of sealants,7 the conclusionsare irrefutable � fissure sealants areeffective in preventing dental caries.They are also cost- effective, not justwhen applied under the controlledcircumstances of clinical trials, but alsoin dental practices,8 and when applied bydental auxiliaries.9

WHAT ABOUT THECHANGING PATTERNS OFCARIES?Since the early days of the use of fissuresealants there have been significantreductions in the prevalence of dentalcaries. The introduction and widespreaduse of fluoridated toothpaste is probablythe most important reason for this butother factors such as diet, oral hygienepractices, some extension of communitywater fluoridation, and possible changesin oral microflora, are also contributory.It has therefore been suggested thatfissure sealants are no longer requiredand are no longer cost-effective. This isfactually incorrect but highlights that wemust change our clinical practices withchanging circumstances.

Caries is not distributed equallyacross countries or communities. It isquite apparent that the majority of cariesis confined to a minority of children.The greatest decline in caries in recentyears has been in previously low riskgroups.10 Children who have had cariesin the primary dentition have a greaterchance of having caries in permanentteeth. There are clearly establishedcorrelations between the lower socio-economic groups and increased cariesprevalence. If the majority of publishedstudies are examined across the world,then it can be demonstrated thatapproximately 25% of the world�schildren have at least 65% of the totalcaries. However, another change in thepattern of caries is also becomingapparent, this is the belief that caries ispredominantly confined to children and

is not a problem past adolescence.Recent longitudinal studies suggest thatthere is a sustained susceptibility tocaries and that the development of cariesis merely being delayed, not eradicated.11

There are, therefore, indications for theuse of fissure sealants in adults.

WHO SHOULD USE FISSURESEALANTS?The answer to this question plainlyshould be �everyone� � given thecorrect targeted selection criteria. Thehidden question refers to cost-effectiveness and value for moneywhich takes into consideration thepersonnel and facilities used forundertaking these procedures. Dentistsare expensive! Fissure sealanttechniques can legally be delegated todental hygienists and dental therapists.These two groups within theProfessionals Complementary toDentistry (PCDs) have been shown toprovide high quality care atsignificantly less cost than the generaldental practitioner. The dentist needs toundertake diagnosis and treatmentplanning but, with well organized andjudicious use of operating anxiliaries,the costs of fissure sealing can then bereduced.9

WHAT ABOUT THE‘SUSPICIOUS’ FISSURE ANDPIT?There is no doubt that dentists havebeen concerned about the possibility ofsealing in caries and the undetectedprogression of this beneath fissuresealant. Numerous studies havedocumented the arrest of caries beneathintact sealants. Composite restorationswhich deliberately seal over carieshave been shown to arrest the progressof carious lesions over a period of nineyears.12 Viable bacterial counts in thelesions have reduced dramatically aftersuccessful sealant applications andthere has been little, if any, cariesprogression, as long as the sealantremains intact. These results led theNational Institute of Dental Research toadvocate sealant use on incipient

Figure 1. Section through a molar fissure that iswell sealed and intact. Although there is somedemineralization at the base of the fissure withthe probability of bacteria left in situ, it isimpossible for any cariogenic substrate topenetrate and therefore the bacteria willbecome non-viable.



lesions.13 Figure 1 illustrates the pointthat, if fissure sealant is intact, therecan be no penetration of substrate to anybacteria left at the base of the fissure.

However, all clinicians who regularlyundertake treatment for young peoplewill have come across surprising,apparently very small cavities in enamel,which have devastating dentineinvolvement, sometimes known as �thefluoride bomb�. If such lesions aresealed, it is more unlikely that thesealant will remain intact because of theundermined enamel. Figures 2, 3 and 4show a seemingly small superficiallesion which, on investigation, proved tobe a large cavity. If a fissure is stainedand suspect on visual examination, abite-wing radiograph may help as far asthe diagnosis of dentinal caries isconcerned. Other diagnostic methodsinvolving electronic systems such aselectrical resistance measurement orlaser and air abrasion techniques may behelpful in the future. If these diagnosticmethods are inconclusive then a�Biopsy� technique should be tried.14

Using a very small round or very fine,short, tapered bur the suspicious fissureor pit is investigated. If this proves to becaries extending well into the dentinethen obviously a conventionalrestoration is required as in Figures 2and 3. If there is only a small amount ofenamel undermined then a composite,glass ionomer (polyalkenoate) orcompomer can be used with a coveringsealant to involve all the remainingfissure system. This has become knownas the Preventive Resin Restoration,(PRR) (see Table 2).

WHICH PATIENTS?This question partly, but not entirely,comes back to a consideration of cost-effectiveness, cost benefit and costutility. There is no doubt that not allfissures are going to become carious.Not all children are caries susceptibleand not all children are at high risk ofthe consequences of dental disease or itstreatment. Not all children are co-operative for dental care. The decisionas to whether to undertake fissuresealants should be a clinical one aftertaking into account the child (or adult)and all their associated risk factors. TheBritish Society of Paediatric Dentistryhas prepared a policy document on theuse of fissure sealants.15 The followingpatient groups are recommended forselection for sealants:

● Children and young people withimpairments;● Individuals who are disabled in sucha way that their general health would bejeopardized by either the developmentof oral disease or the need for treatment;● Children and young people withcaries in their primary teeth should haveall susceptible sites on permanent teethsealed.

Significant medical conditions whichput children at risk from theconsequences of dental disease includecardiac problems, immunosuppression,

bleeding disorders, blood dyscrasias andmetabolic and endocrine problems.These do not necessarily mean that theperson is susceptible to caries but theywill be much more at risk if caries doesdevelop. Children with physicaldisabilities and limitations of manualdexterity may also be regarded as apriority group. However, some childrenwith learning disabilities may not havethe co-operation necessary for fissuresealants to be applied with the degree ofmoisture control that is vital to success.

WHICH TEETH – ANDWHEN?Although primary molar teeth have notnormally been regarded as teeth to besealed, there are some situations whenthis may be required. For example, ifthere is no permanent successor and theprimary molar is to be kept in the mouthfor some time, or if children fall into thepriority groups as above. These childrenshould also have the susceptible sites ofall permanent teeth sealed; these includethe pits and fissures of permanentmolars and palatal pits on incisor teeth.The upper lateral incisor is a commonsite for a palatal invagination which maybecome carious and jeopardize pulpalvitality.

If one of the permanent molars hasbecome carious then there is very good

Figure 2. A relatively recently erupted lowerright second permanent molar in a thirteen-year-old who has already lost the first molar due tocaries. This fissure appears to be suspicious.

Figure 3. A 'Biopsy' undertaken of thesuspicious lesion shown in Figure 1 hasrevealed extensive occlusal caries.

● Investigate Clinically- Visual examination- Electrical Resistance Measurements- Lasers- Air abrasion techniques- Fibre-Optic Transillumination

● Investigate Radiographically- Occlusal caries may show as ashadow at the amelo-dentinal junction;- Caries may show beneath a fissuresealant;

● Investigate using a ‘Biopsy’ technique- Use a very small round or shorttapered bur;- If caries extends into dentineconventional restoration is required;- If minimal amounts of enamel areundermined then a composite , glassionomer or compomer is inser ted withcovering sealant over all fissures.(Preventive Resin Restoration)

Table 2. The ‘Suspicious’ Fissure and Pit.


Dental Update – October 2000 373

scientific evidence for sealing the otherthree as quickly as possible.16 If firstpermanent molars have become carious,the second molars should be sealedwhen they erupt.

The advice always given was to sealteeth as soon as they were eruptedsufficiently to obtain adequate moisturecontrol, particularly teeth with deepfissures. There is now increasingevidence that teeth may become cariousmany years after eruption and certainlyfissure sealants are more likely to failwhen placed on newly erupted teeth.Potential risk factors need to be re-assessed on an individual patient basisat frequent intervals. If sealants becomedefective they need to be replenished inorder to maintain their marginalintegrity.

TECHNIQUES – IS THEREANYTHING NEW?There are many new advances in dentalmaterials and there is now increasingchoice in light cured and chemicallycured sealants � those activated byultraviolet light have long ago been leftbehind. Chemically cured fissure sealantretention is at least 60% after 5 years.The light cured systems have been lessevaluated in longitudinal studies as theyare a more recent introduction.However, the studies that are availablesuggest that light cured resins areperhaps retained even better thanchemically cured ones.

Although alternative materials such asglass ionomers (polyalkenoate cements)and compomers have been suggested asalternatives to the Bis-GMA resins, the

scientific evidence on retention andcaries prevention has shown these not tobe as efficacious. There have been morerecent studies suggesting that the glassionomer cements can be regarded as a�fluoride depot� rather than just aphysical barrier.17 This material may beused where patient co-operation isdoubtful, perhaps as an interim measureuntil compliance improves.

Some manufacturers have deliberatelyincorporated fluoride into sealants in anattempt to improve caries prevention.There are two common methods offluoride incorporation, an anionexchange system (organic fluoridecompound chemically bound to theresin) and the addition of a fluoride saltto unpolymerized resin. At present, allthe commercial products that areavailable fall into the latter group. Invitro studies have shown that the surfacelesion depths of artificially inducedcaries lesions were significantly reducedwhen a fluoride releasing sealant wascompared with a conventional sealant.18

Conseal F (Southern Dental IndustriesLtd, Bayswater, Victoria 3153 Australia)is a sealant which gives an intensiveinitial fluoride boost in conjunction withlong-term fluoride therapy. It is lightcured and of low viscosity which helpsfissure penetration. However, it wouldbe fair to say that the incorporation offluoride into a resin may compromisethe integrity of a sealant and long-termin vivo studies are still required todetermine if the fluoride additionimproves caries inhibition.

A recent review by Morphis et al.19

has considered the clinical and in vitroevidence for the use of fluoride pit andfissure sealants.

There has also been a recentsuggestion that use of dentine bondingagents may substantially enhance thesealant retention rate. The primermonomers associated with the fourthand fifth generation dentine bondingagents are more effective in penetratingthe surfaces of etched enamel than aconventional fissure sealant, probablyowing to their extremely high diffusionco-efficient.20 If two coats of the primerare applied followed by a fissuresealant, a higher retention rate has been

shown. This could be particularlyimportant on primary teeth whereetching and retention are moreproblematic. More research on thisaspect is certainly required as this couldbe a considerable step forward.

GETTING IT INTOPERSPECTIVEFissure sealants are only a part of theprogramme of prevention, but animportant part of the armamentariumagainst dental caries. They must becombined with other preventivemethods and are particularly useful incombination with optimal waterfluoridation and with topical fluorideuse. However, prevention is not an easyoption. It demands a change inphilosophy from the old �drill and fill�to highly developed communicationskills and a thorough understanding ofdental disease and how to avoid it.

REFERENCES

1. Cueto EI, Buonocore MG. Sealing of pits andfissures with an adhesive resin. J Am Dent Assoc1967; 75: 121-128.

2. Epidemiology and Oral Disease PreventionProgram. National Institute of Dental Research.The national survey of dental caries in United Statesschool children 1986–87. National Institute ofHealth 1989. Publication Nos. 89-1147.

3. Holloway PJ, Blinkhorn AS, Hassall DC, Mellor AC,Worthington HV. The assessment of capitation inthe General Dental Service Contract. 1. The levelof caries and its treatment in regularly attendingchildren and adolescents. Br Dent J 1997; 182:418-423.

4. O’Brien M. Children’s Dental Health in the UnitedKingdom 1993. London: Office of Population,Census and Surveys, 1994.

5. Lewis JM, Morgan MV. A critical review ofmethods for the economic evaluation of fissuresealants. Community Dent Health 1994; 11: 79–82.

6. Mjor IA, Burke FJT, Wilson NHF. The relative costof different restorations in the UK. Br Dent J 1997;182: 286–289.

7. Llodra JC, Bravo M, Delgado-Rodriguez M, Baca P,Galvez R. Factors influencing the effectiveness ofsealants – a meta analysis. Community Dent OralEpidemiol 1993; 21: 261-268.

8. Ismail AJ, Gagnon P. A longitudinal evaluation offissure sealants applied in dental practice.J Dent Res 1995; 74: 1583-1590.

9. Riordan PJ. Can organised dental care for childrenbe both good and cheap? Community Dent OralEpidemiol 1997; 25: 119–125.

10. Manton DJ, Messer LB. Pit and fissure sealants:Another major cornerstone in preventive dentistry.Aust Dent J 1995; 40: 22–29.

Figure 4. The caries found in Figure 2 was soextensive that it was restored with aconventional amalgam material.



11. Ripa LW, Leske GS, Varma AO. Longitudinalstudy of the caries susceptibility of occlusal andproximal surfaces of first permanent molars.J Public Health Dent 1988; 48: 8–13.

12. Mertz-Fairhurst EJ, Adair SM, Sams DR, et al.Cariostatic and ultraconser vative sealedrestorations: Nine year results among childrenand adults. ASDC J Dent Child 1995; 97–107.

13. National Institutes of Health. Consensusdevelopment conference statement on dentalsealants in the prevention of tooth decay.J Am Dent Assoc 1984; 108: 233–236.

14. Smallridge J. Management of the stained fissure

in the first permanent molar National ClinicalGuidelines and Policy Documents. Dent PractBd 1999; 33-36.

15. British Society of Paediatric Dentistr y. Fissuresealants in Paediatric Dentistr y PolicyDocument. January 2000.

16. Broadeur JM, Payette M, Galarneam C.Treatment cost savings with universal coverageof dental pit and fissure sealants in Quebec.J Can Dent Assoc 1997; 63: 625–632.

17. Williams B, Laxton L, Holt RD, Winter GB.Fissure sealants: a 4 year clinical trialcomparing an experimental glass polyalkenoate

cement with a bis glycidyl methacrylate resinused as fissure sealants. Br Dent J 1996; 180:104–108.

18. Hicks MJ, Flaitz CM. Caries like lesionformation around fluoride realising sealant andglass ionomer. Am J Dent 1992; 5: 329–334.

19. Morphis TL, Toumba KJ, Lygidakis NA. Fluoridepit and fissure sealants: a review. Int J Paed Dent2000; 10: 90-98.

20. Hotta K, Mogi M, Miura F, Nakabayashi N. Effectof 4-MET on bond strength and penetration ofmonomers into enamel. Dent Mat 1992; 8:173–175.

BOOK REVIEW

A Clinical Guide to Complete DentureProsthetics. By J.F. McCord and A.A.Grant. BDJ Books, London, 2000 (76pp.,£29.95). ISBN 0-904588-64-5.

This is a new addition to the �clinical guideseries� published by the British DentalJournal. The majority of the material hasalready formed a series of publishedarticles in the Journal and, as is customaryfollowing publication, a stand-alone bookhas been released.

On first impressions the book isattractive. It is in A4 format and thematerial is well illustrated. The introductorychapter sets the scene and this is importantfor, as the authors stress in the secondparagraph, �This book is not intended toreplace standard textbooks ofprosthodontics, but rather to serve as achairside guide/aide memoir of clinicalprocedures for the general dentalpractitioner with an interest in completedenture therapy.� This statement should beborne in mind as the reader progressesthrough the book.

To start, this is a useful book for theinterested postgraduate practitioner as itacts as complementary material to thosewho are reading around the subject. It doesdemand a good understanding of the basicsof complete denture prosthetics as some ofthe concepts are at an advanced level.Examples include the use of a papillameterand the re-introduction of the Gothic Archtracing technique. The authors do cover avariety of techniques as they advancethrough the progression of completedenture construction. The chapters follow atraditional approach with each covering inturn: the history and examination,impressions, registration, trial dentures and

delivery of complete dentures. Theinformation is sound and practical and willhelp the more able dentist interested inProsthetics to explore alternative methodsof treating the edentulous patient. The lastchapter covers specific clinical problemareas and is a real gem! There are practicaltips on conventional immediate completedentures, copy (template) dentures, relinesand rebases, overdentures and implant-retained complete dentures. This lastchapter could form the basis for a newseries of articles.

Although overall the book is well written,there is some unevenness in the style thatdetracts overall. For example, Chapter 3 isstrong on text with some pictures but littlein the way of aide memoir tables. This isdifferent from Chapter 10 which ispredominantly a set of tables with little textand pictures.

In spite of these niggles, it must bestressed that the authors ought to becongratulated for breathing new life into adifficult subject area that has been coveredbefore. I would recommend practitioners tobuy the book in order to allow a freshapproach and different perspective.

Professor A.D. WalmsleyBirmingham Dental School

Treatment Planning for TraumatizedTeeth. By Mitsuhiro Tsukiboshi.Quintessence Publishing Co. Ltd., 2000(120pp., £48). ISBN 0-86715-374-1.

This book was a delight to review. I read itfrom cover to cover in a weekend. Itreminded me of reading a good novel; I didnot want to put it down. The author isJapanese and the contents of the book areheavily influenced by the publications and

research of Dr Jens O Andreasen.Treatment Planning for Traumatized Teethis true to its title. The book consists of 11short chapters. These cover anatomicalconsiderations, classification of injuries,examination, crown fractures, rootfractures, subluxation, extrusion, intrusion,luxation and avulsion. Trauma to thesupporting structures and to the primarydentition are also included. True to theQuintessence Publishing Co. format, thebook is very well produced with their useof high quality, coloured photographs,exceptionally good black and white printsof radiographs and colourful diagrammaticrepresentations.

The layout of the book with its mix ofpictures and text is very pleasing to the eyeand easy to read. However, some smallquirks in translation and editing into theEnglish version have meant that, in acouple of places, it is difficult to understandand this could confuse someone who is notfamiliar with the basic management oftraumatized teeth. The tooth notationsystem used is one with which I am notfamiliar. Nevertheless, the cases used by theauthor to illustrate the injuries and theirmanagement show clinical expertise of thehighest order, despite the fact that surgicalintervention has been favoured in someinstances when a more conservativeapproach may have been indicated. Oneinteresting observation is that thetraumatized teeth of Japanese childrenappear to require bleaching more often thatthose of British children.

This is a well produced book givingconcise information and recommendationson the management of traumatized teeth. Itwill be a useful addition to the books on myshelf.

Iain MackieCentral Manchester Healthcare NHS Trust

BOOK REVIEW