sealants by huangyuarong

VIEWS: 10 PAGES: 8

									        and
Sealants preventive restorations:reviewof
            and               for
effectiveness clinical changes improvement
   J.     DDS,
RobertFeigal PhD

Abstract                                                             use
                                                                Sealant
             are
   Sealants effective caries-preventive     agentsto the ex-       Dental sealants can be an effective preventive mea-
tent they remain  bonded teeth. Preventive
                         to                   resin restora-    sure against pit and fissure decay. When     placed with
tions (PRR) a proven
             have         record,but are susceptible fail-
                                                     to         care and then routinely maintained, sealants represent
ure as the overlyingsealantfails. Careful analyses studies
                                                   of           an exceptional preventive service. 3 Nonetheless, many
reveala measurable  failure rate of sealants(5-10% year)
                                                    per         dentists expressfrustration with sealants or a distrust
that mustbe addressed. under best of circumstances,
                        Even      the                           for the long-term benefit of this treatment. In fact,
sealants fail. Therefore, ntistry(as wellas third-party
                        de.                              sys-   utilization of sealants has long disappointedadvocates
tems) mustaccept that sealants needvigilant recall and          of their use. National survey data from 1988-91 show
                                                                4                    of
                                                                that less than 20% USchildren have any sealants.
properpreventive               In
                   maintenance. addition,it is clear that
               use
cost-effective of sealants involve
                             will        selectiveapplication   Theremaybe many    reasons for poor utilization of seal-
on teeth withthe greatestcariesrisk. Caries   risk analysisof   ants. Early in the history of sealant advocacy,it was
            as
the patient wellasthe toothis anessential in the treat-
                                            step                         that
                                                                assumed a lack of informationtransfer plus a skep-
                                                                ticism of etched bonding methodscontributed to low
mentplanningprocess.To improve      sealantsuccess, newma-
                                                                sealant use) Now,with better dissemination of knowl-
                 are
terial advances suggested.      Data~om studies usingan in-     edge about sealants and a natural progression of
termediate layer of dentin bondingagent betweenetched           clinician confidencewith bondedmaterials, these rea-
        and
enamel sealant showdramatic        reductionof failure for      sons shouldnot be significant deterrents to use. Adding
                      in
sealants,particularly instancesof molars     judged difficult   to residual effects of the attitudes just mentioned,other
to seal dueto earlystageof eruption            Dent
                                      (Pediatr 20.’285-         factors play a role in discouragingsome   clinicians from
92, 1998).                                                      prescribing sealants. Twosuch factors are an "in the
                                                                trenches" clinician’s perspective that sealants often do
    t is a dauntingtask to speakor to write about den-
I   tal sealants after all that has been previously
    reportedon this topic. Mostdental professionalshave
                                                                not satisfy the profession’sneedfor perceivedcertainty
                                                                with treatment 6 and a common      third-party payment
                                                                perspective that penalizes the clinician for necessary
determined  their stand on sealant use. Likegoodreligious       sealant repair or replacement.
zealots, each can quote studies that support only their
                      and
side of the argument can quietly dismiss the rest.                sedant/l~RR
                                                                The       spectrum
   In the face of such a challenge, this paper offers a                        of
                                                                   Management pit and fissures for caries preven-
review of sealant failures and sealant effectiveness.                                                         a
                                                                tion and/or caries restoration has become complex
Fromthe review comesuggestions for improved de-                 topic in contemporary dentistry, a topic involving the
cision-making and more vigilant maintenance that                confluenceof data from diverse areas of investigation
will lead to an enhanced    future for sealants and PRRs.       such as dental materials, diagnostics, caries epidemiol-
In addition, the author offers a changein sealant tech-         ogy, microbiology, and remineralization. Debate
nique to increase clinical success with sealants. The           continues as to the best and most appropriate meth-
technique changefollows from a large-scale clinical             ods to diagnosecaries in pits and fissures. In addition
study of difficult-to-seal teeth.                               to that diagnostic debate, questions remain about the
   This is not an exhaustive review of the sealant/             best therapy and/or treatment for those fissures with
PRR  literature, rather a focused one. For a contem-            or withoutcaries.
porary review of sealants and methodology,I suggest                Treatment planning of what was once considered
                                    and
rhe excellent paper by Waggoner Siegel. ~ Anex-                 a "simple" sealant nowinvolves a series of decisions
cellent review of the issue of effectiveness was                involving risk assessment of the patient, tooth, and
2
reported by Weintraub.                                                                           the
                                                                surface. In addition, performing service of a seal-

PediatricDentistry-20.’2, 1998                                                                      of
                                                                                      AmericanAcademy Pediatric Dentistry 85
ant causes the astute practitioner to make decisions on                    retention. It truly was news that we could bond to
how to prepare the fissure (if preparation is at all in-                   tooth. The surprise was that any of the early polymers
dicated), what bonding agents to use, what sealant to                      stayed in place. The first adaptation of the etch tech-
use, how to place the sealant, and how to maintain                         nique to fissures was reported in 1967,'° and the
the sealant.                                                               profession was amazed when studies reported appre-
    Sealant and PRR do not represent the only tech-                        ciable sealant retention.
niques available for management of the pits and fissures                       Investigators and readers were likely to think of any
of teeth. A variety of methods exist, including no treat-                  retained sealant as a success, because they did not re-
ment until frank cavitation. A recent article by Croll                     ally expect all of the sealant to stay in place anyway.
and Cavanaugh 7 lists and illustrates six clinical ap-                     Therefore, the profession entered into sealant investi-
proaches, one being a conventional sealant and five                        gations with a crude and probably overly optimistic
being variations on the PRR technique depending on                         criteria for success. In most people's minds, partial re-
depth into enamel or dentin and on the caries risk of                      tention of sealant on an occlusal surface was often
the surface.                                                               considered "success".
    Philosophies of practice vary. Many modern prac-                          With the perspective of two decades of sealant stud-
titioners are less quick to fill or seal pits and fissures,                ies to guide us, we can now see that this overly
as caries prevalence and caries rate have slowed con-                      optimistic evaluation was incorrect. Partial loss of seal-
siderably, even on these surfaces. And it is important                     ant is still an unresolved issue in sealant studies. What
to acknowledge this "watch and wait" philosophy for                        we do know is that there is a range of conditions we
questionable lesions. Regular observation prior to                         may judge as "partial loss" or "partial retention". Some
making a treatment decision is worthy of additional                        of these may be successful sealants, while others are
study as analysis of the latest national surveys of car-                   clear failures. Data from past studies have made the case
ies rates by surface shows occlusal surfaces having the                    that any appreciable "partial loss" of sealant leaves a
greatest decrease in actual caries numbers.8 Obviously,                    tooth equally susceptible to caries as an unsealed con-
some of the recent decrease in caries on these surfaces                    trol tooth."- 12
relates to the disproportionate amount of caries still                         It is also important to remember that all sealants
found on occlusal surfaces. Nonetheless, pit and fis-                      exhibit partial loss in the strict sense of the term, be-
sure caries is decreasing in real numbers. The carious                     cause all show reduced volume over time. Elegant work
attack is less prevalent on those surfaces, and caries                     by Conry and coworkers,13'l4 using a computer-driven
progresses less quickly.                                                   profilometer, has documented the extent of sealant area
    Tooth surfaces that warrant sealant coverage still                     and volume change on sealants in vivo. So, sealant loss
confront the clinician with long-term treatment deci-                      of some type is continuous. Clinically significant
sions. The science behind these decisions demands                          changes occur when sealants have lost enough mate-
additional attention by our profession.                                    rial to leave a deep fissure uncovered or when sealants
                                                                           fracture, leaving a sharp margin with the remaining
Evaluation of sealant loss and partial loss                                tooth, as these defects often lead to eventual caries.
   Buonocore first reported that bonding to tooth sur-                         Short of frank caries development, there exists no
faces was possible.9 Further work showed remarkable                        strict definition of what constitutes a failed sealant.
success, unexpected by a profession previously famil-                      While the scientists may debate the issue, the clinician
iar only with restoratives dependent upon mechanical                       makes daily decisions on when to repair and when to




Figl. White sealant on a mandibular first       Fig 2. White sealant on a mandibular first       Fig 3. White sealant on a mandibular first
molar. The buccal sealant and the bulk of the   molar. All aspects of this sealant are intact    molar. The distal one-third to one-half of this
occlusal sealant are intact and "successful".   with the exception of the most lingual part of   sealant has fractured and debonded. A major
Sealant loss has occurred leading to several    the lingual occlusal fissure. No caries are      defect is present at the sealant-tooth margin
supplemental grooves of the occlusal surface    detectable.                                      and two primary grooves are uncovered.
being exposed and stained. No primary groove
is uncovered. No caries are detectable.

86   American Academy ofPediatric Dentistry                                                                        Pediatric Dentistry - 20:2, 1998
leave alone. Examples the difficulties of judgingseal-
                      of                                     success on tooth types (molars and bicuspids), and sec-
ant failure can be seen in Figs 1-3. Which these of          ond, by assumingthat presence of any sealant on the
sealants are failures andwhichare continuingsuccesses?       surface wasa success.
Eachof these sealants showsloss of material compared            Becauseit’s easy to see that bicuspids have better
with the original placement,so they should be recorded                                                        et
                                                             sealant retention scores than molarsin the Going al.15
as partial loss. But whichof themare clinical failures?      paper, and as molarsare the teeth most in needof car-
The tooth in Fig 1 has lost material but has not un-                         I
                                                             ies prevention, will limit additionalliterature citations
covered any fissure anatomy.Fig 2 has lost material          to those papers that give data on permanent   molar seal-
                                                a
over only one small fissure area. Fig 3 shows sealant        ants or offer long-termevaluations of success.
with half the originally covered fissure anatomynow             127-year study by Mertz-Fairhurst and colleagues
                                                                A
opento caries attack.                                        ®
                                                             reported on two products, autopolymerizing Delton
   Partial loss of sealant is a provocativeissue because     ( a second-generation sealant) and UV-polymerized
it affects judgment sealant successand effectiveness.
                    of                                                ®
                                                             Nuvaseal (a first-generation sealant). This wasat the
Clearer definition of the important(clinically relevant)     end of the Nuvasealera, as the Deltonand other simi-
partial losses wouldgo far to determineneed for pre-         lar generation products were proving moreeffective.
                     of
ventive maintenance sealants.                                So, looking only at the morefavorable Deltondata, this
   It is informative to re-evaluate past data regarding      report showsthat after 7 years, first permanent    molars
sealant success in the light of our contemporary     ques-   had 66%sealant retention while partial retention was
tions. Somesealant studies have carefully reported            14%.Total sealant loss was 20%and, comparingcar-
retention by tooth type and surface. Thosedetailed re-       ies rates on the sealed half of the mouthwith the
ports offer another glimpse at the issues of sealant         nonsealedcontrol half, caries reduction effectiveness
effectiveness. While many    review articles and sympo-      was 55%.That meansthat 32 of the treated teeth were
sia concerningsealants report only summary      data from    carious and 71 of the control teeth were carious after
these studies (due to the overwhelming    volumeof seal-     7 years. Data from both materials showedthat partial
ant data), a close look at some  detail is in order.         retention of sealant did not automatically guarantee
   One exampleis the classic work by Going, Haugh,           protection. Caries rates on molars with partially re-
Grainger, and Conti,~5 "Four-yearclinical evaluation         tained sealants (by the authors’ definition) were equal
of pit andfissure sealant." This excellentstudy included     to caries rates on the contralateral control teeth.
paired control "nonsealed" teeth with experimental              Barrie et al.~6 compared  three sealant types in 5- to
sealed teeth, andit carefully reported successstatus for     6-year-old Scottish children. In this more contempo-
each tooth type and surface, as well as caries status of     rary field study, occlusal sealants were judged
sealed and nonsealed teeth. The article contains a           "completelysealed" in two comparativesubsets of pa-
wealthof information.Yet, this referenceis often cited                                            ®
                                                             tients. In the first, Prismashield was compared      with
or summarized "The sealant was fully retained on
                as                                           Estiseal   ® and 24-mo retention          was 71% for
     of
50% all paired permanent       teeth at 48 months." This     Prismashield, with 53%for Estiseal. The other com-
         does
summary not tell the full story.                             parison group had 24-mo retention of 81% for
                                          of
   In the article, there is a breakdown data by tooth        Prismashield and 88%for Concise.
type. Sealant retention is listed as "all present" on 50%       Onreviewof these studies, as well as reviewof other
of all teeth, 64%on premolars, and 29%on molars.             published sealant data and recent IADR    abstracts, one
"Partly missing" data are 28%of all teeth, 21%on             could concludethat the expectedsealant loss from per-
                    on
premolars, and 40% molars. This leaves sealant "all          manent molars is between 5 and 10%per year. In
missing" on 22%of all teeth, 15%of premolars, and            addition, becausecaries risk returns after sealant loss,
31%of molars.                                                it’s suggestedthat the caries rates for sealed teeth re-
   Comparing  caries rates on treated and control sides      flect the 5-10%   loss multiplied by the usual population
of the mouthleads to the following data on percent           caries rates for pit andfissure surfaces.
effectiveness: All teethe43%, Premolars--84%, and
Molars--30%.                                                 The      of
                                                                 value sealant   upkeep
   This discussion is not a criticism of Goingand co-           Otherstudies indicate better success. Oncloser evalu-
workers, as they report all the details openlyin their       ation, these studies often report data froma population
paper and as other sealant studies have a similar mag-       in whichthe sealants are regularly maintained. Regular
nitude of failure, but this is an importantdiscussion                    was
                                                             maintenance not a part of the study protocol in the
           need
because-we a critical, realistic viewof sealant suc-         previouslycited clinical studies. Therefore,reports that
cess now.Therefore, weneed to look moredeeply into           include recall and maintenance   offer important infor-
the data than simply reporting the meanvalues. Our           mationon the value of regular upkeepof sealants.
early viewsof sealant successor failure wereunrealisti-                and            ~7
                                                                Romcke coworkers report a 10-year observa-
cally brightenedby two factors: first, the averagingof       tion of more than 8000 sealants placed on first

PediatricDentistry-20..2, 1998                                                                   of
                                                                                   AmericanAcademy Pediatric Dentistry 87
 permanent molars in an annual dental care program             caries-free, with 24%resealed, and 15%restorations.
 on Prince EdwardIsland, Canada. Completesealant               Again, in this data set approximately 5%of sealants
retention, without need for resealing, was 41%at 10                                         or
                                                               neededadditional maintenance restoration each year,
                    for
years, and 58-63% 7 to 9 years. This agrees with                  Basedon the reported sealant data, wemust be re-
the previously stated concept of 5-10%of loss each             alistic in our ownexpectations and in the way we
year. Patients in this study wereseen yearly and seal-         market sealants to the public. Sealants need continu-
ants wereannuallyrepaired as necessary. One   year after       ing care, and this maintenancemust be factored into
insertion, 6%of sealants required maintenance. After           the real andperceivedcosts of sealants.
the first year following placement, the maintenance
needs droppedto 2-4%each year. In light of a vigi-                           to
                                                                         teeth
                                                               Diagnoses-which seal?
lant annualrecall and repair program,these authors can             Theneed to be realistic about sealant retention and
report sealant success (freedomfromcaries) of 96%for           effectiveness logically leads to a needfor diligence in
the first year and 85%after 8-10 years.                        the decision to seal. If cost effectiveness is the main
   A study of sealants on first permanent molars in            factor in this decision, onemust carefully choosewhere
                 and      ~8
Swedenby Wen& Koch indicates a similar fol-                    to put sealants.
low-up model. The authors state that sealants were                 In a recent report by Heller et al., 2~ an important
"controlled" once a year. The758 sealed surfaces were          comparisonwas made. By fortuitous circumstances of
followedfor 1-10 years, and the resulting examinations         the study, someof the patients originally evaluatedfor
showed80%   total sealant retention after 8 years. An-         the study did not enter the sealant application portion
other 16%of the surfaces were judged as partial                of the study. Thepatients whodid not receive sealants
retention. After 10 years, only 6%of the sealed occlusal       were all rescreened after 5 years, along with the seal-
surfaces showed  caries or restorations.                       ant-application subjects. This afforded the examiners
   Another more recent report strengthens the argu-            an opportunityto compare    caries rates on teeth in both
ment that sealants need regular maintenance.                   sealed and nonsealedsubjects. Anadditional advantage
Chestnutt et al. 19 reported on more than 7000 seal-           of the study is that the examinerscored molar surfaces
ants applied by private practitioners in Scotland. After       as "sound"or "incipient" at the original screening ap-
4 years (during whichtime it is assumedthat normal             pointment. Therefore, the investigators were able to
recalls and regular dental care continued), 74%of the          report subsequent  5-year caries rates on teeth originally
sealed tooth surfaces remained fully sealed and 18%            scoredas incipient, as well as those originally scoredas
werescoredas deficient or failed sealants. Of the sur-         sound. The results are most intriguing. After 5 years,
faces originally scored as deficient sealants, 23%  were       molarsscored initially soundbecame      carious at a rate
scored as carious 4 years later. This compared   with a        of 13%in the nonsealed cases and 8%in the sealed
21%caries rate on surfaces originally scored as sound          cases. This difference (13 to 8%)is a modest   caries pro-
                                         a
but not sealed. Sealed surfaces showed caries rate of                                       after 5 years, molars
                                                               tective effect. Alternatively,                    initialJy
only 14.4% during the 4-year period. Conclusions               scored as incipient became   carious at a rate of 52%in
from these data suggest that deficient sealants are not        the nonsealedcases and only 11%in the sealed cases.
effective in caries prevention, arguing for continued          This difference (52 to 1 I%) is striking.
follow-upof the originally sealed surfaces at every re-            The data from Heller’s study argues that if wewere
call visit. Maintenance sealants is vital for success
                        of                                     able to effectively rate teeth as "at risk" and concen-
over the long term.                                            trate our sealant efforts on these, the caries preventive
                                                               effect of sealants wouldbe extremelysignificant. Den-
Practitionerreports                                                                                        of
                                                               tistry is presently struggling with methods caries risk
   Cliniciansare often skeptical of data fromlarge clini-      assessmentfor patients. It is clear that better sealant
cal studies, feeling that the results are not representative   success wouldfollow better risk assessmentof the pa-
of their ownexperience. Regardingsealant success,              tient, the tooth, and the surface. This risk-associated
private practice reports confirmthat even detail-ori-          decision to seal has been advocatedsince someof the
ented operators struggle with sealant failures. Dr. Dan        early sealant studies, ~ but it continues to be an issue
Shaw, a Board-certified pediatric dentist from Eden            of contention.
Prairie, Minnesota,has kept personal records of seal-              Canweagree on criteria to rank patients on caries
ants in his practice for the last 10 years.2° His data will    risk? Possibly not. Canweagree on criteria for tooth
be submitted for publication soon. All sealants were           surfaces at risk? Maybe,although our perception of
placed by him with the help of a chairside assistant.          such a simple judgment as "deep occlusal anatomy"
Patients in his practice whohave been treated with             varies from practitioner to practitioner. At least we
sealantsshow  sealedsurfaces90%   caries-free after 5 years,   should agree that each practitioner makean initial as-
with 6%of the surfaces requiring resealing and 4%re-                     of
                                                               sessment risk, usingtheir own     personalcriteria, prior
quiting restorations. At 8 years, the numbersare 61%           to treatment planning for sealants.

88 AmericanAcademy Pediatric Dentistry
                 of                                                                             Pediatric Dentistry- 20:2, 1998
   choice cost-effectiveness
Tooth and              ofsealants                                 The practitioner maychoose to seal the susceptible
   Determination of sealant effectiveness has been             molar at an early stage of eruption, thus affording the
done on populations that were part of a sealant                tooth the best of preventivecare. Yet, this practitioner
project8 and by comparing   caries-rate survey data with            be
                                                               may at risk for personallyfundingthe necessaryseal-
sealant-retentiondata.22’ 23It is clear that sealantssave      ant replacementin the near future.
surfaces from becoming   carious if the sealant stays in             pits lingual
                                                               Buccal and          groovesofmolars
place. But the numberof sealants that need to be                  Twoother areas of susceptibility and sealant diffi-
placed in order to prevent one surface’s restoration is        culty are buccalpits andlingual grooves.Relativelyfew
important to keep in mind. In populations with av-             studies report data on buccal and lingual pits and
erage caries rates, it has been calculated that 5-10           grooves, yet these anatomical areas on molars account
sealants must be placed to save one molar surface from         for a significant portion of all pit and fissure decay.
becoming  carious. In bicuspid teeth, whichhave lower          Data from national surveys showthat buccal pits of
                                               are
overall caries rates than molars, the numbers closer           mandibularfirst molars and lingual groovesof maxil-
to 25-40  (in somecomputations up to 100) sealants             lary first molars contribute a significant numberof
placed for every surface saved. Teeth most at risk for         cariouslesions to the overall caries rates for thoseteeth.
caries will therefore showthe best effectiveness num-          Fromthe 1987 National Caries Survey by the National
bers for sealant applications. As the caries rates             Institute of Dental Research (NIDR),buccal surfaces
decline, the effectiveness values decline.                     of mandibular molars contributed about 40%of the
   Oneshould note that cost-effectiveness computa-             total caries on that tooth while lingual surfaces of max-
tions often assume 100%sealant retention. That is                                                        8
                                                               illary molars contributed about 30%. Anecdotally,
never the actual case. Contemporary      sealant studies       clinicians find it difficult to place successfulsealantsin
showcaries increments on teeth originally sealed for           buccal and lingual fissures. This perspective is evi-
the study. For example, Mertz-Fairhurst and cowork-                                               to
                                                               dencedby the decision by many avoid sealing these
ers~2 in their 7-year study in Augusta,Georgia, had a          surfacesdue to the frustration of early sealant loss.
meansealant retention rate of 66%, but a caries                   Thereport by Barrie et al. ~6 on Scottish 5 and 6 year
incidence of 10%and a percentage effectiveness                 olds is one of the fewrecent studies that gives sealant
of 55%. Therefore, the number of sealants to be                data on buccal and lingual surfaces. Twoyears after
placed in order to save a single surface from caries           initial application of the Prismashield and Concise
is larger than previously calculated in most cost/             sealants, 39 and 350/0 of buccal and lingual surfaces
benefit computations.                                          were judged "completely sealed". These numbersare
   It is importantto target sealants to the mostsuscep-        significantly lowerthan the occlusal sealant success of
tible surfaces of the most susceptible teeth. A                81 and 88%,respectively, for the two materials in the
complicationof this philosophyis that these teeth and          same study.
surfacesare often the mostdifficult to successfullyseal,          Clearly, the buccal and lingual surfaces are more
leading to high rates of failure.                              difficult to protect than are the occlusal surfaces. In-
Difficult-to-seal
            teeth                                              stead of losing 10%of occlusal sealant per year,
                                                                                              of
                                                               investigators often lose 30% the buccal/lingual seal-
Newly erupted molars
                                                               ants per year.
   Oneexampleof caries susceptibility combined          with
sealant difficulty is the newlyerupted permanent       first               based on        and
                                                               Improvements material technique          changes
molar. This tooth is commonly     carious within 2 years          Newer  materials mayhelp reduce the risk of early
of emergence   through the tissue. In fact, manyfirst          failure in difficult-to-seal teeth. My researchhas focused
permanentmolars have fissures that are questionable            on this type of need. Use of an intermediate bonding
                       with
or that are diagnosed incipient caries as they erupt.          layer between enameland sealant has been shownef-
Thedifficulty for the practitioner involveshowto pro-          fective in the face of majorsaliva contamination ourin
tect this at-risk or "sticky"fissure prior to full eruption.   previouslab studies25-27 28 well as a clinical study.
                                                                                           as
                          24
Dennisonand coworkers reported in 1990that seal-               Therefore, weknow    that in controlled situations, seal-
ants placed on molars early in eruption were far more          ant sensitivity to moisture contamination can be
likely to require replacement   within 3 years. At a stage     virtually eliminated by the careful use of this method.
of eruption in whichthe distal tissue is at the level of       In these studies, bondstrength of sealant to enamelis
the distal marginalridge, the replacement     rate for seal-   increased25.26 and microleakageat the sealant/enamel
ants was 26%. At an eruption stage whena tissue                                   27
                                                               margin is reduced in teeth with bondingagent plus
operculum existed over the distal marginal  ridge, the seal-                      to
                                                               sealant compared control teeth with sealant only.
ant replacement  rate was54%.In comparison,this group          Others have confirmedthese findings of bond strength
of investigators found 0%replacementsnecessary for a           29
                                                               improvements.
sampleof sealants placedat later stages of eruption.              Fromour previous studies it is clear that on clini-

Pediatric Dentistry-20:2, 1998                                                                     of
                                                                                     AmericanAcademy Pediatric Dentistry 89
 cally dry teeth, the bond remainsexcellent using the                 Other bonding agents have also shownsignificant
 intermediate bondingagents. Therefore, weare teach-                                          ®
                                                                  benefit. Prime and Bond as an intermediate agent
 ing this bondingagent layer as a normalfeature of all             (tested as our newest cohort to reach 12 months)re-
 sealant applications.                                            duces failures even more than does Tenure. Of the 38
    Anotherongoingclinical study, briefly described,              control teeth, 9 (24%)occlusal sealants have failed
involves taking patients whoseteeth have been judged              while only 5 (14%) occlusal sealants with Prime and
 "difficult to seal" and comparing  long-termsealant ef-          Bondhave failed at 12 months. For buccal and lingual
                    one
fectiveness between side of the mouth      that is sealed         sealants in the Prime and Bondgroups, the numbers
with normal sealant technique, as described by                    are 11 failures out of 32 controls (34%) and only
manufacturer’sspecifications, and the other side that             failures out of 30 (7%). Fromthis study, weconclude
is sealed with the addition of an intermediate bonding            that reductions of one-third ofocclusal sealant failures
agent betweenthe etched enameland the sealant. Seal-              and one-half of buccal/lingual sealant failures are pos-
ants are scored at each recall using strict criteria for          sible. One small addition to the normal technique
marginal integrity, marginal staining, and anatomic               makesour sealant methoddemonstrablybetter.
form. The condition of the sealant is recordedat every                Other improvements are afforded by the bonding
recall visit with the use of an intraoral video camera.           agent, in addition to the improvedretention of the
       are
   We able to significantly decreasefailures of seal-             sealant. These have been reported by clinicians using
ants on early eruptedmolarsand on buccal/lingual sites            the bonding-agent methodin practice. In an attempt
by adding of a bonding agent onto the etched-enamel               to makesealants that are more resistant to occlusal
surface, air thinning that agent, and then placing the            wear, more highly filled sealant has been produced.
sealant20.31 Fig 4 is a representative graph of data of                 of
                                                                  Some these are thick and viscous, causing difficulty
the first year of experience in two study groups with             in spreadinginto small fissures. Thebondingagent step
                    ®
and without Tenure primer as an intermediate bond-                                     of
                                                                  aids the placement these viscous materials. Theseal-
ing layer below the sealant on approximately 240                  ant spreads better after bondingagent placement, and
sealants. Sealantfailure (by our strict studycriteria)            wets the surface of the fissures better. 32 Theresult is a
buccal and lingual sites at 12 monthswas28%for con-               filled sealant that is moreresistant to wear, whichhas
trol teeth (sealant only) and 10%for the bonding                  33
                                                                  deeply penetratedall the necessaryfissures.
                                              is
agent/sealant group. Similar improvement seen in                      Benefits of the intermediatebondingagent layer are:
occlusal sealant success. Four-yeardata on these study                1. better bond strength and less leakage in poten-
cohorts are being analyzed for publication. The 1-year                                 2~-27’
                                                                         tially wetareas     29
differential in failure rate betweenthe two groups as                                     28’ 30, 31
                                                                      2. improvedretention
shownin Fig 4 continues through the observed 4 years
of sealant wear.                                                     3. better flow of viscoussealant material on the tooth
                                                                         surface32,33
                          Buccal/l_ingual
                                    Surface                           The bonding agent technique advocated here offers
      5O                                                          additional advantagesin chemicaltechnologyto aid the
                                                                  practitioner. Hydrophilicagents in the adhesive system
      40                                                          overcomeinadvertent moisture contamination, while
              --~$ealant                                          the adhesive systemitself serves as the low-viscosity,
                   Tenurep us SealantJ                            flowable wetting agent for the interface between   etched
  ,~ .~o                                                          enameland the filled resin.
                                                                      The bondingagent step is one exampleof material-
      ,o                                                          based improvement. More advances can be expected
                                                                  frommaterials scientists in the near future. Theexcit-
                                                                  ing aspect of improvingour sealant materials is the
                                                                  potential benefit in cost effectiveness. Withmoreseal-
                                                                  ant staying in place, the effectivenessdata will improve.
       0
     Placement       I Month       3 Month   6 Month   12 Month   In addition, clinician judgment  about whereto use seal-
                                    Time                          ants and when to seal may be broadened, so that
                                                                  ultimately, those surfaces most susceptible to decay
Fig This shows
   4. graph buccal/]ingua]failure one
                           sealant in                             could havethe benefit of early sealant.
           studygroupmore 200
representative on than sealants the  over first
year the      Cirlces
    of study. represent  thepercent ofthe
                                failure buccal/                           resin
                                                                  Preventive restorations
      sealants sealed the
lingual      on                       bonding
               teeth with intermediate agent                         A logical extension of preventive sealant strategy
      primer group) sealant. represent
(Tenure inthis        plus    Squares sealanl                     involves use of resin restorative materials plus sealant
      on sealed sealant Differences
failureteeth with        alone.     arestatistically              to restore tooth material lost in discrete areas of caries
        atall points.
significanttime                                                   attack on a fissured surface. First reported by Simonsen
90 American Academy of Pediatric Dentistry                                                        Pediatric Dentistry- 20:2, 1998
andStallard, 34 this 20-year-oldconcepthas gainedwide                  a surface with the samecaries rate as a nonsealed
approval. The procedure involves use of the dental                     surface.11,12
handpiece to removeonly those areas of the tooth af-                3. Regular maintenance and sealant addition when
fected by caries, followedby bondingresin restorative                  necessaryis importantin long-termcaries protec-
material into them,and finally coveringall restorative                 tion after sealant placement.
material and any remaining fissured anatomy with
                                                                    4. Much better effectiveness data will result if seal-
sealant. Theobvioussaving of tooth structure is sig-
                                                                       ants are used on teeth with a true predilection
nificant. Byavoiding the old philosophyof "extension
                                                                       to caries
for prevention" tooth preparation and replacing it
with the idea of discrete removalof caries, there is a              5. Better materials and better use of bondingagents
major reduction in intracoronal preparation and tooth                  with sealants will improve overall effectiveness on
structure    loss.                                                     all teeth--particularly      on those teeth now
   Many vitro and clinical studies showthat the pre-
        in                                                             thoughtof as difficult to seal.
ventive resin restorations score well compared theto              Conclusions
single surface amalgam    restoration. 35-3s Long-term
                      of
clinical comparisons PRRs      with traditional amalgam              1. Sealantbonding                                will
                                                                                        that is less moisture-sensitive
restoration of these surfaces are limited to a fewstud-           open up the beneficial use of sealants to patients who
ies, two of whichare cited here.                                  are not able to complywith rigorous isolation meth-
   Welbury and coworkers35 reported on a British                                           or
                                                                  ods, i.e., handicapped very youngpatients.
population in whichpaired molars were restored with                  2. More realistic expectationsfor sealants will drive
         or
amalgam PRR.During a 5-year trial that looked at                  marketingand payment    plans for sealants such that the
174 pairs of molars, 11 amalgams   failed and eight PRRs          practitioner is not liable for the normalwear-and-tear
failed. Survivalstatistics determined  mean survival time         losses of the material.
for amalgamto be 61.5 mo and PRRto be 63.3 mo.                    References
   Mertz-Fairhurstand et al. 38 report 9-year results of
restorations placed over carious lesions after minimal                          WF,
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This paper is ~omthe ContinuingEducationCourse"Restorative Materials for Pediatric Dentistry Today~
What You Should Know Today and WhereWeAre Going!’; at the AAPD   51st Annual Session, May22, 1997.
The course was sponsoredby the AAPDFoundation.




          Academy PediatricDentistry
92 American     of                                                                                              Dentistry 20:2,1998
                                                                                                        Pediatric       -

								
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