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PEDIATRIC DENTISTRY/Copyright199t by
e
The American Academy o! Pediatric Dentisuv
• Volume 1)/ Number 1
';'
Resistance of occlusal fissures to demineralization
after loss of glass ionomer sealants in vitro
Liisa Seppã, LicOdont, DOdont Helena Forss, LicOdont
Abstract
Seueniv-one caries-itee huina n occ/ usal físsures were used effect, even after they had disappeared macroscopi-
for this study. Tuicniq-tuio físsures were scalcd with a glass calIy. Long-tenn retention may not be necessary :: the
ionomer sealant (Fuji Iononier Type m® - c-c Dental In- material has anticariogenic properties that increase the
dustrial Corp. Tokyo, [apan), 24 were uiidened with a caries resistance of newly erupted fissures. Fluoride
âiamond bur and sealed with theglass ionomer sealant.and 25 released from gIass ionomer and taken up by enamel
were left unsealed. After one week, ihe sealants were remoued (Forsten 1977; Retief et aI. 1984; Swartz et aI. 1984; Forss
as completely as possible with a probe. Ali fissures were and Seppã 1990) may give prolonged protection. On the
demineralized for senenweeks. Sections made frOI/1 lhe other hand, in our dinical study, microscopic exami-
fissures uiere examined unth a potarizing microscope, and the nation of occlusal surfaces showing partial or totalloss
depths of lhe fissure tesions were nieasured. Tire mean lesion of sealants revealed that in most cases, residual material'
depths for controle, sealed natural fissures, and sealed wid- was observed in the bottom of the fissures (Torppa-
ened [issures were 143, 93, and 75 11m, respectively. A Saarinen and Seppã 1990).
stalistically significant difference was noted betuieen thc fwo In the case of resin sealants, dinicians still debate
experimental graups and the conirol group (no sealant). The whether ar not it is necessary to widen narrow fissures
resulls suggest that [issures sealed untlt glass ionomer are before sealing (Meiers and Jensen 1984). As for glass
more resistani to demineraíization tltan control fissures, even ionomer, McLean and Wilson (1977) found that the
after macroscopic sealant loss. This lIIay be tire result of ti/e filling cement could not penetrate fissures narrower
combined effect of fluoríde released by glass ionomcr and than 100 11m,and recommended widening the fissures
residual material in lhe botiom of the fissures. before sealing. AIthough a material with smaller par-
"i
l tide size, such as glass ionomer developed for fissure
i Introduction sealing, seems to penetra te deeper into the fissures '
The use of glass ionomer cement as a fissure sealant (Mount and Makinson 1978), widening might improve
material has increased in recent years. So far, few retention of glass ionomer sealants anel provide longer
studies of its efficacy have been reported, and the results protection. However, there is no information 011 _'o
of these studies have been conflicting. In the study by resistance of widened fissures in the case of sealant loss.
Williams and Winter (1981) using glass ionorner filling The purpose of the present study was to examine
cement as a sealant, sealant loss was higher for glass whether fissures sealed with a glass ionomer cement
ionomer than for resin, but there was no significant designed for fissure sealing are less susceptible to'
difference in caries incidence between teeth sealed with demineralization than control fissures, even after the
1 , these.two materials, McKenna and Grundy (1987) re- sealant has been removed. Another purpose was to
ported that the retention of glass ionomer cement was study the effect of widening the fissures on resistance to .
l-i
1: 93% after six months. However, studies by Shimokobe demineralization after sealant loss.
I '
et aI. (1986) and Boksman et al. (1987) using a gIass
11 ionomer material specialIy designed for fissure sealing, Materials and Methods
!,. almost a11sealants were Iost within the first six months. Ten human third molars and 30 remolars were used
I
. An interesting finding in the studies by Williams and for t 1e study. Ali fissures were caries free by visual
Winter (1981) andby Shimokobe et al, (1986) was that ínspection .. After extraction, the teeth were stored in ..
gIass ionomer sealants seemed to exert a cariostatic 40% ethanoI. The crowns were separated from the roots .
PEDIATRICDENTlSTRY: jANUARy/FEBRUARY - VOLUME 13, NUMBER 1 39

2. .' -and bisected longítud inall y, except for a few premolars
with a very short occlusal fissure. The tooth halves were
divided randornly into three groups. The fissures in the
first group were left unsealed, The fissures in the second
group were cleaned with a rotating brush'and pumice,
rinsed carefully, and sealed with glass ionomer sealant
(Fuji Ionomer Txpe m® - G-C Dental r nd ustrial Corp.,
, Tokyo, japan) using a small ballpoint instrumento
, Mixing was performed according to the manufacturer' s
. instructions, When the sealanl had lost ils glossincss, it
was covered with a varnish provided by the manufac-
turer. The fissures in the third group were widened
with a nàrrow, flame-type diamond bur (di'ametera:5
mm) _~&._~!_~!~~.i&~:_~p~e~. Carc wns InkL'11not [o
penetra te 1nto the dentin. The occlusal surfaces were
1 cleaned with pumice, rinsed, and sealed, as in the sec-
~;ond group. .: '.'
Fig 1. A diagram c1escribing lhe measurernent technique. The
t ~.~ ·iE~~_.~ample was stored for on~n a test tube arrows show the points at which the measurements of lesion
;yCohtaining ilistilled water. After that, the sealants were depth were made.
~Jên1ovéd as completely as possible with a sharp probe,
1soi.that -no residual material was left in the fissures
"macroscopically. Ali tooth surfaces (except for the
sfissures) were covered with acid-resistant wax
200
.(Ptepon® - Bayer, Wetzlar, Cermany), The samples
'thén Were immersed for seven weeks in 0.1 M lactic acid E
:::l.
~ buffer.ipl-l 4.3 in 5% carboxymetylcelÍ~19_~~t~p~-~-uce I 150
artificial fissure l~ons. After deminerallzation, longi- f-
o,
tuomal sechons were cut from the sarnples and the W
O
sectíons were ground to approximately 90 11m thick. z 100
The -fissure lesions were viewed with a polarizing O
miéroscopé (Leitz Diaplan® - Leitz, Wetzlar, Ger- ü5
W
many) and photographed. TIH~ depth of the lesion was
-l
50
assessed frorn the photomicrographs by rneasuring
; . traverses running perpendicular to the enarnel surface
O
at six standardized points (Fig. 1), and the means of six
2 3
measurements were calculated.
- , Data were analyzed using one-way analysis of vari- Fig 2. Mean lesion depth, I = contrai, 2 = sealed natural (issures,
ance for t1etecting significant differences and Scheffe's J = sealed wiclened fissures.
multiple comparison tests for pairwise comparisons.
Results Discussion
5eventy-one fissures were sectioned successfully. The long-term retention of resin sealants is 60-80%
e méan depth of fissure lesions was 142.8 um (50 (Mertz-Fairhurst et al, 1984; Simonsen 1987; Wendt and
3.8) in control fissures (N = 25), 92.7 11m(50,6) in sealed Koch 1988). Even though the initial retention rate is high
natural fissures (N = 22), and 75.1 11m (35.7) in sealed (Weintraub 1989), regular contrai of surfaces sealed
" idened fissures (N= 24, Fig. 2). The differences be- with resin sealants is necessary, at least during the first
"eeJl the control and sealed fissures were statistically few years. For glass ionomer sealants, the retention rate
"gnificant (P < 0.01), whereas the difference between appears to be lower, although long folIow-ups have not
tural and widened fissures was not significant. Figs been reported. However, the present results suggest
- • (see next page) show typicallesions in sealed and that the fissures sealed with a glass ionomer sealant are
control fissures. more resistant to dernineralization than unsealed Iis-
iàualsealant material was observed insix natural sures, even after the sealant appears to be lost. This may
~='-L.~ a d in four widened fissures. No lesion was be the result of the combined effect of the increased
er lhe residual material. fIuoride levei of the enamel ar pia que, and residual
U v!FEBRUARV - VOLUME 1 J, NUMOER 1

3. fig 3. A typical fissure lesion in a widened fissure sealed with fig 4. A typical fissure Iesion in a contraI fissure.
glass ionomer.
material in the fissures. Although sectioning of the ionomer remain caries resistant for long periods can be
fissures probably removed most of the residual mate- assessed only in a long-term clinical study.
rial, sometimes it was observed in the bottom of the
fissures. This is probably often the case clinically after We are grateful to Ms Hanna Eskelinen for skillful teehnical assis-
tance.
visible sealant loss, as observed in our previous study
(Torppa-Saarinen and Seppâ 1990). Dr. Seppã is assistant professor and Dr. Forss is an instructor in the
"1 The results also suggest that widening fissures does Department of Preventive Dentistry and Cariology, Faeulty of Den-
not make them more prone to demineralization than tistry, University of Kuopio, Finland. Reprint req~est5 shpuld be sent
natural fissures, even when the sealant is lost macro- to: Dr. Liisa Seppa. Department of Preventive Dentistry and
Cariology, Faculty of Dentistry, University of Kuopio, P·.O.B.6, SF-
scopically. A tendency to decreased demineralization 70211, Finland.
in the widened fissures when compared to sealed natu-
ral fissures probably resulted from enhanced retention Boksman L, Gratton DR, McClItcheon E, Plotzke OB: Clinical evalu-
of residual material, although, because of sectioning, ation of a glass ionorncr cerncnt as a fissure scalant. Quinh.ssencc
h Int 18:707-9, 1987.
t is could not be confirmed in the present study. Forsten L: Fluoride release from a glass ionomercement. Scand] Dent
When considering the results, one must remember Res 85:503-5, 1977.
that an in vivo experiment does not fully reflect oral Forss H, Seppâ L: Prevention of enamel demineralization adjacent to
conditions. It also should be emphasized that although glass ionomer filling materials. Scand J Dent Res 98:173-78, 1990~
glass ionomer sealants increased the resistance to MeKenna EF, Grundy GE: Glass iõi10mer eement fissure sealants
applied by opera tive dental auxiliaries retention rate after one
demineralization considerably, lesion formation was year. Aust Dent J 32:200-3,1987.
not inhibited completely, Thus, the results do not allow Mcl.ean JW, Wilson AD: The c1inical developrnent of the glass
us to conc1ude that resealing of fissures in the case of ionorncr cerncnt. ll, Some clinical applications. Aust Dent j
Sea 1an t Ioss IS never necessary wiith g Iass ionomers.
. . 22:120-27,1977. ,
Meiers [C, [ensen ME: Managernent of the questionable carious fis-
However, glass ionomer may be a good alternative to sure: invasive vs noninvasive techniques. J Am Dent Assoe
resin sealants, at least when regular check-ups and 108:64-68,1984.
rapid resealing of fissures showing sealant loss are not Mertz-Fairhurst EJ, Fairhurst CW, Williams JE, Della-Giustina VE,
possible. Whether the fissures sealed with glass // Brooks JD: A comparative clinical study of two pit and fissure
sealants: 7-year results in Augusta, GA. J Am Dent Assoe 109:252-
55,1984.
~
PEOIATRIC DENTISTRY: jANUARY/FEBRUARY - VOLUME 13, NUM8ER 1 41

4. Mount G], Makinson OF: Clínical characteristics of a glass-ionomer Swartz ML, Phillips RW. Clark HE: Long-term F release from glass,
'cement. Br Dent J 145:67-71, 1978. ionomer cements.] Dent Res 63:158-60.1984.
: Re~JefDH, Bradley EL. Dentorr[Ci Switzer P: Enamel and cementum •. Torppa-Saarinen E, Scppâ L: Short-term retention of glilss-ionomer
,·,t"f' ~~oride uptake from a glass-ionomer cement. Caries Res 18:250- fissure sealants. Proc Finn Dent Soc 86: 83-88.1990. '
I· ~57} 1984 ' . Weintraub ]A: The effectiveness of pit and fissure sealants. J Public
.shtlnbkobe ri, Komntsu H, Knwaknmí S, Hirota K: Clinicnl evaluation Health Dent49:317-30, 1989., -
" .'.1 'bf'gláss-Ionomer cement used for seala nts. J Dent Res 65:812 (abst r Wetidt L-K, Koeh G: Fissure scalnnt in pcrrnnucnt Ilrs] molars aftcr 10
fi . 0),1i986. . years. S~~DenUJ2:181-85, 1988..
::JSim ., e.fi'R]:: Retention and effectiveness of a single application of Williams B, Winter GB: Fissure sealants. Further results at 4 years. Br
:,yq: whíte sealant after 10 years. J Am Dent Assoe 115:31-36. 1987. Dent J 150:183-87, 1981.
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',f f~(i,:, Developing an office manual
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.~;:'~.'~.yourdent~l;office manual should be reviewed and updated periodically in order for policies to .
: 1 . 2'!f.;;:~remain useful. An article in General Dentistry recommends the manual contam several sections,
:.~. " including: "
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'; . The dental team Infection contraI
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Philosophy of practice The patient record
The office team X-ray and photography
Communícatíon Plaquc contraI II
.Iob desçriptions Organizational
Emergencies Equipment maintenance ,I
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Safety (OSHA regulations) Supplies I
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Patient education
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Dental tray set-ups and procedures Is
Preventive dentistry I '.
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Business office systems Restorative dentistry I
Telephone procedures
; 'Appointrnent control
Fixed prosthodontics I
Oral surgery
Office forrns and filing I
Endodontia
Accounts receivable Periodontia I
Treatment plans and consultations
Removable prosthodontics
Recalls ànd correspondence
Orthodontia
Insurance procedures
CoIledions
i Employee manual
!-" Evaluations
Chairside manual
Training
Patient management
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42 PEf'IATRIC DENTlSTRV: )ANUARV/FEURUARV - VOLUME 13, NUMIlER 1