Tips for successful posterior resin composite restorations
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SPECIAL EDITION
very deep (Figure 7&8).
Tips for successful When the outer carious lesion is removed
according to the guide of staining with caries
detector and natural discoloration, patients don’t
posterior resin feel severe pain during the caries excavation
(Figure 9). Clinical evaluation of the VAS (Visual
composite restorations Analogue Scale) value of the pain during the
treatment of caries revealed that the younger
patients tended to feel stronger pain than older
patients. However, the pain was much less than
Dr. Junji Tagami dentin, which is infected by bacteria and easily the pain during a shot of local anesthesia
Chairman and Professor
Department of Cariology & Operative
stained with caries detecting dye solution, is [Terano et al., JDR 79 abst.#1162, 2000].
Dentistry removed, the cavity floor dentin is not sensitive, Though various methods for diagnosing dentin
Tokyo Medical & Dental University even if it is very close to the pulp. Once the caries removal have been proposed, this
5-45 Yushima 1 Chome Bunkyo-ku Tokyo intact dentin is exposed in the cavity, it must be
113-8549 Japan technique is the most practical for achieving
tagami.ope@tmd.ac.jp very sensitive because the dentinal tubules are “minimum invasive” caries treatment.
open and transfer the stimuli to the pulp. After removal of the outer carious dentin,
Because of the development of material Bonding with perfect sealing of the tubules is
science and cariology, it became very easy to the cavity floor consists of the so called inner
essential for decreasing sensitivity. Furthermore, carious dentin, which is also named as caries
obtain successful results with posterior cutting of sound dentin may cause pulpal
restorations using adhesive resin composites. affected dentin. It is clearly shown that the
inflammation or hyperemia. In most cases, caries affected dentin is not permeable (Figures
The successful results include esthetics, long these pulpal changes recover with time,
lasting function, and of course, no 10-13). It means that the cavity floor dentin is
however, some cases requiring not sensitive. The SEM picture exhibits the
post operative sensitivity of the endodontic treatment may occur
tooth. At the same time, the Bonding with occluded dentinal tubules with mineral deposits
because of irreversible pulpal even after the phosphoric acid etching (Figure
procedures and manipulation of the perfect sealing changes.
materials should be simple and 14). That’s why the lining is not necessary when
of the tubules The procedure of this this technique is applied. The lining is
easy to reduce the operator’s technique established by Dr.
technique sensitivity. is essential for recommended when the intact dentin was cut or
Fusayama [New Concepts in when the patients felt significant pain during the
1. Cavity preparation decreasing Operative Dentistry, Quintessence cavity preparation.
Cavity preparation for the Publishing, 1980] is as follows; 1. When this minimal invasive technique for
sensitivity. opening the cavity with high speed
adhesive restoration is extremely caries removal and cavity preparation is used,
simple and easy. The most cutting (Figures 1&2), 2. excavation post operative tooth sensitivity seldom occurs.
significant reason for the post operative of the outer carious dentin according to the Even when the cavities are left as it is without
sensitivity is over-cutting of dentin during the guide of caries detector and natural discoloration any filling, the tooth is not sensitive because the
cavity preparation. When the outer carious using slow speed steel burr or hand instruments cavity floor dentin consists of the caries affected
(figures 3-5), 3. repeating
the staining of the lesion
and its removal until INSIDE THIS ISSUE
staining becomes light pink
or less (figure 6). In
addition, the wetness of
the cutting debris and the
sensitivity of the tooth are
very valuable information
Figure 1 Before treatment Figure 3 Discoloration is seen for diagnosing the amount s Continuing
of dentin to be removed.
Then the bonding and Education Credit
filling materials are applied material in this issue.
without lining materials
even when the cavity is Take the free exam at
www.dentrek.com/kuraray.asp
Figure 2 Cavity is opened with high speed Figure 4 Caries detector is applied
diamond point
dentin with the occluded tubules. recognized when you compare
with any of the composite resins
2. Selection of the adhesive resin which are used in your clinic. This
High quality adhesive provides good is one of the most unique
sealing and reinforcement of the tooth characteristics of Clearfil AP-X.
substance and filling material. Adhesive resin Stickiness of the resin pastes
which exhibits strong bonding, low technique to filling instruments is reduced by
sensitivity and durable bond to both enamel and increasing the consistency of the
dentin should be selected. paste in the resin materials so Figure 9 VAS value of pain during the caries
SE Bond is very well known as extremely called packable or condensable removal and cavity preparation LA: VAS Figure 12 Occlusal view after preparing the
flat surface. Lesion with the discoloration is
excellent adhesive resin for both enamel and value during the shot of local anesthesia
removed according to the clinical
dentin. SE procedures.
Bond
consists of
two steps,
which is self-
etching
primer
application Figure 10 Extracted molar with cavitated
and bonding lesion
resin Figure 5 Lesion to be removed is clearly Figure 7 Bonding procedure is applied Figure 13 After the etching, the red dye
application. indicated solution infiltrated from the pulp. The dye
was seen only at the area of the intact
It does not dentin, indicating the cavity floor dentin is
require the not sensitive.
wet bonding
technique
since the Especially in the
water rinsing Figure 11 The occlusal surface was ground cases of posterior
is not and the root was also removed. The crown restorations, the wet
necessary. segment was bonded to a plastic plate and
Wet bonding Figure 6 Removal of the outer lesion, and Figure 8 After filling and polishing
connected to a syringe to be able to apply a
pressure from pulpal side. The pulp
bonding technique is
technique is the prepared cavity chamber was filled with a red dye solution. very difficult to apply,
well known because
as a resin. However, the
technique sensitive bonding Though various configuration of
high consistency resin
procedure, since both the over-wet methods for composites may have posterior cavities is
and over-dry condition result in diagnosing disadvantages such as very complicated.
decrease of the bond. Especially in the difficulty of
the cases of posterior restorations, dentin caries
removal have spreading, especially in obtaining good
the wet bonding technique is very a very small and
difficult to apply, because been proposed, adaptation between
complicated cavity, incremental layers.
configuration of posterior cavities is The
this technique is and poor adaptation to Figure 14dentindentinal tubuleswiththe caries at
very complicated. affected were occluded mineral Even the
the most both cavity walls and deposits even after the phosphoric acid
consistency is very thin
Operator technique sensitivity the incremental etching.
with SE Bond is much lower than practical for before polymerization,
interface. flexural strength, Vickers
with the all-in-one type adhesive, achieving When the cavity wall
which consists of only the self- hardness, and tooth brush wear resistance of
“minimum adaptation and voids in Class I resin Clearfil AP-X are very high. This is mainly
etching adhesive. Because of the composite restorations were
extremely simplified bonding invasive” caries because of the high filler content of 85.5 weight
treatment. investigated, it was revealed that % (Figure 15). Barium glass is used as the filler
procedure of the all-in-one type thick-consistency composite had
adhesives, both performance of particles and this glass is relatively soft
more problems related compared to silica filler
bonding and technique sensitivity are generally to voids and wall adaptation than
sacrificed. particles. Because of
the medium and thin consistency this relatively soft filler,
3. Selection of the resin composite composites [Opdam et al., Dental polishing of this resin is
Clearfil AP-X, which is a heavy filled semi Materials 12:230-235, 1996]. very easy.
hybrid type resin composite, was developed for Thus, Clearfil AP-X, which can
both anterior and posterior restorations. be classified as a medium- 4. Long term clinical
The consistency of Clearfil AP-X must be consistency resin composite, can performance
felt relatively thin compared to most posterior be said to be very easy to fill into Figure 15 SEM of the AP-X, showing the
In most of the
resin composites. However, Clearfil AP-X is not cavities of posterior teeth and to heavily filled with various sizes of fillers. papers reporting the
sticky to the instruments. This unique property obtain excellent wall adaptation longevity of posterior
was achieved by an original technology, named without voids. This property is also resin restorations, the
“interfacial boundary control” between filler advantageous when the incremental filling wear of the composite resin was not a
particle and matrix resin. It is very easily technique is applied to deep cavity restorations, significant reason for the replacement of that
2
restoration. The main cause of failure for Technique sensitivity incomplete removal of
composite restoration is usually secondary caries Miyazaki et al. [American water from the hybrid
around the restorations. To increase the Journal of Dentistry 13:101-104, layer and insufficient pen-
longevity of the restorations, the refurbishing of 2000] also reported the larger varia- etration of the resinous
the restorations is believed to be very effective tion in bond strength of an adhesive material into the collagen
with total etching and wet bonding layer are considered to be
[Mjor, Adhesive Dentistry 19:236, 2002]. main causes of the degra-
The survival rate of the composite technique than a self etching adhe-
sives (Figure 4). In the case of the dation of the hybrid layer.
restoration in posterior teeth was reported to be wet bonding technique, both over Figure 4 Dentin bond strengths(MPa) of As the result, the quality
higher than that of cast restoration [Kubo et al., wet and over dry conditions result in adhesives with a self-etching primer and of the hybrid layer should
Japan J Conserv Dent.44:802-809, 2001]. The phosphoric acid, obtained by the well
the decrease of the bond. experienced operators, untrained clinicians be inferior in the case of
calculation was based on the results of 19 years A new type of bonding materi- attended a continuing education program, and total etching technique
clinical assessment. This result is enough to al, an all-in-one type adhesive, con- the dental students. and/or wet bonding tech-
assure the propriety of the Fusayama’s sists of a real one-step bonding pro- nique.
technique. The recent materials can be expected cedure. The self-etching adhesive is There might be a
to exhibit much better results than the reported applied and cured. The adhesive has concern if it is safe to
survival rate at 19 years, approximately 80 %, to include some amount of water to leave the acidic primer on
be acidic, and it has to be polymer- the tooth surface, since
because of the improvements of the materials. water rinsing is not
ized with dissolved smear layer.
Although the bonding procedure is applied after the applica-
What is Clearfil SE Bond? simplified, the technique sensitivity
and bonding performance seem to Figure 5 Long term dentin bond strengths
tion of the self etching
primer. Fortunately, a
Concept of SE Bond be sacrificed. In fact, these all-in-one (MPa) of a conventional adhesive with acidic seven-year clinical evalua-
The technology of self etching primers was conditioner and adhesive, and a product with
adhesive resins demonstrated lower the self-etching primer. tion of an adhesive using
developed by Kuraray Medical Inc. This was bonding than adhesives with a two- the self-etching primer,
achieved by the development of the so called adhe- step self-etching primer [Nakaoki et Clearfil Liner Bond 2,
sive resin monomers, named MDP or Phenyl-P al., 79th IADR, Abst.#1815, 2001]. revealed excellent results
(Fig. 1). The adhesive resin monomers includes the Another recent study revealed that without any de-bonding,
acidic part, that is phosphate. Because of this SE Bond showed the most stable nor pulpal response
acidic part, the primer solution containing the and strong bond when compared [Akimoto et al., Japanese
MDP becomes acidic, and can etch the enamel with an adhesive with phosphoric Journal of Conservative
and dentin surface. acid etching (Single Dentistry 2001]. Enamel
The wet bonding Bond) and an adhe- and dentin are very strong
technique is required only sive of all in one sys- buffers against the acid.
when the acid is applied tem (Touch & Bond) After application of the
and rinsed with water. In Figure 6 Phosphoric acid etching provided
[Nikaido et al.,31st the typical etching pattern of the primer for 20 seconds, the
the case of the bonding AADR, 2003]. Even longitudinally cut enamel prisms acidity of the primer must
procedures using the self when students with- be decreased dramatically.
etching primer, the uncer- out the experience of The excess of the primer
tain method of wet bond- using adhesive resins solution is also removed
ing technique is not prepared the speci- by air blasting. If it is
developed
required since the collagen Figure 1 Adhesive resin monomers Phenyl-P,
by Kuraray Medical Inc., MDP and mens, the best harmful to the dentin/pulp
fibers are already incorpo- which include the phosphate bases. Because results were obtained complex, the excellent
rated with the resin of the acidic part, they are named to be acidic
with SE Bond. Also, clinical performance with-
monomers in the primer monomer, which enables to reduce the pH of
the primer solution. SE Bond exhibited out post operative sensitiv-
solution. The bonding pro- Figure 7 Self-etching primer of SE Bond ity cannot be obtained.
less technique sensi- provided relatively weak etching effect
cedure of Clearfil SE Bond tivity than the other compared to phosphoric acid. The dissolved and
(Figure 2) is, application of bonding materials. softened smear layer can
self etching primer for 20 The only prob- be blown away from the
seconds, drying the sur- lem with this adhe- surface when the excess
face with air blast remov- sive system is the consistency of the of the primer is removed. Also, the primer is
ing the excess primer solu- self etching primer, which is very known to show some antibacterial effect. Even if
tions from the surface, thin. The primer flows very easily some bacteria and smear layer remained, excellent
application of the bonding down the cavity walls, however, this clinical performance and durable bonding prove
resin, and light curing. Figure 2 Clearfil SE Bond consists of one
bottle self-etching primer and one bottle light problem is easily solved by applying that it would not be a problem.
With this extremely simple cured adhesive the primer 2 or 3 times during the
bonding procedure, very Enamel bonding
application time [Ogata et al., Another concern may be the bonding to
strong bonding to both Operative Dentistry 24:81-88,
enamel and dentin, as enamel, since the acidity of the self etching primer
1999]. is considered to be much lower than that of phos-
well as to various dental
materials can be obtained Long term bond durability phoric acid. Actually, etching effect of the self-etch-
(Figure. 3) [Harada et al., The bonding durability of the ing primer is much less than that of the phosphoric
Dentistry in Japan 36: 47- adhesive with a self etching primer acid etchant (Figure 6, 7). However, a recent study
53, 2000]. SE Bond is has been reported to be superior revealed that SE Bond showed more stable bonding
used in the clinic for not than the adhesive with total etching to both cross-cut enamel prisms and longitudinally-
only restorative procedures technique even after 6 years (Figure cut enamel prisms than the adhesive with phos-
but also intraoral repairs Figure 3 Bond strengths (MPa) of the SE
5) [Burrow et al., Adhesive Dentistry phoric acid etching (Figure 8) (Shimada et al.,
of fractured restorations, Bond to enamel, dentin, metal, and porcelain. 19:254, 2002]. It is because of the Operative Dentistry, 28:20-27, 2003). The phos-
secondary caries and Alloy Primer (Kuraray Medical) and Activator very stable hybrid layer formation, phoric acid etching may be too strong to etch the
so on. (Kuraray Medical) were used for the bonding though it is very thin. Effects of longitudinally cut prisms, which resulted in the sep-
to metal and porcelain respectively.
3
Kuraray America, Inc. Presorted
2501 East Piedmont Road, Suite 143 Standard
U.S. Postage
Marietta, GA 30062 Paid
Woodstock, GA
Permit No. 374
aration of enamel prisms just beneath the bonding Opdam et al. (American Journal of Dentistry dentinal fluid or precipitation of protein in dentinal
interface (Figure 9, 10). In the clinical situation, the 11:229-234, 1998) evaluated the post operative fluid, such as globulin and albumin, resulting in a
cavity walls consist of mostly longitudinally cut sensitivity with class I restorations. Post operative reduction in dentin permeability (Tagami et al.,
enamel prisms. As shown in the Figures 7, sensitivity was Arch oral Biol 39 suppl: 146S, 1994). Self etching
the SEM of the enamel after the self-etching observed with 25% primer is expected to show the desensitizing effect
primer application does not look great, how- of the cases re- since the self etching primer shows the coagulation
ever, we etch the tooth for the bonding, but stored with the ad- of protein.
not for the SEM. hesive using phos- Based on our work, SE Bond is believed to
Unfortunately, the uncut enamel sur- phoric acid etching, have the best advantage in preventing post opera-
face is much more acid resistant than whereas none of tive sensi-
ground enamel, and the self-etching primer the cases restored tivity, as
is not strong enough for strong bonding using a self etching compared
(Kanemura et al., American Journal of Figure 8 Enamel bond strengths (MPa) of SE
primer, Clearfil with the
Dentistry, 27:523-530, 1999). In the cases Bond and Single Bond to horizontal and axial Liner Bond 2. adhesives
of the bonding of fissure sealant and direct sectioned surfaces with the longitudinally cut The desensi- using
composite veneer without cutting the enamel prisms, and to tangentially sectioned tizing effect of the phosphoric
surface with cross-cut prisms.
enamel surface, phosphoric acid etching is adhesive resin acid. After
recommended. monomers is con- the phos-
sidered to con- phoric acid
Post operative tribute to decrease etching, Figure 11 Incidence (%) of post-operative tooth
In fact these sensitivity the post operative the primer sensitivity after composite resin restorations
all-in-one adhesive According to a tooth sensitivity. self-etching primer,
application using the adhesives withwith light cured
phosphoric acid etching
clinical evaluation of The desensitiz- has a pos- adhesives, or chemical cured adhesives.
resins demon- post-operative tooth ing effect of sibility of
strated lower sensitivity after resin adhesive primer decreasing the sensitivity; however, the etching
composite restora- application to increases dentin permeability by enlarging tubule
bonding than tions, teeth restored Figure 9 Laser scanning microscopic image of hypersensitive diameters. SE Bond, which does not require any
adhesives with with the materials uti- the bonding interface between enamel and teeth was con- strong acidic treatment, and is not technique sensi-
lizing self-etching Single Bond showing the crack propagation
two-step self- along the prisms under the interface. firmed in clinical tive as compared to the wet bonding technique,
primer showed the studies (Tagami provides a successful restoration. s
etching primer. less post-operative et al., Dental
sensitivity than bond- Materials Journal
ing materials using 6:201-208, 1987,
phosphoric acid etching (Figure 11, Suda et al., Dental
Unemori et al., Journal of Dentistry, 29:7- Materials Journal Published by Kuraray America., Inc.
13,2001). It is considered that adhesive 9: 163-166, 101 E. 52nd Street
materials with self-etching primer have the 1990). The mecha- New York, NY 10022
(800) 879-1676
advantage of better bonding performance nism of the desen-
Figure 10 Laser scanning microscopic image of
and less technique sensitivity in the bond- the bonding interface between enamel and SE sitizing effect was www.kurarayamerica.com
ing procedure compared to those materials Bond showing the tight bonding without crack postulated due to News-05/03 Printed in USA 05/03
with phosphoric acid etching. propagation.
the coagulation of
