The effect of immediate dentin sealing on the marginal adaptation and bond strengths of total-etch and self-etch adhesives

Volume 102 Issue 1

The Journal of Prosthetic Dentistry Duarte et alHickey Award

The Judson C. Hickey Scientifi c Writing Award

Dentistry

The Journal of

The Editorial Council for The Journal of Prosthetic Dentistry announces the fourteenth annual Judson C. Hickey Scientific Writing Award. This award honors Dr Hickey’s distinguished career as Editor of The Journal of Prosthetic Dentistry and his contributions to dental education, re-search, and administration.

The annual award of $5000 is divided into 3 categories: Research/Clinical Sciences article: $2500; Clinical Report article, $1500; Techni-cal article, $1000. In each category, the award will be granted to the primary author of the most outstanding article published in the JPD between October 1, 2008, and September 30, 2009.

Criteria and Regulations

Published articles in each category will be judged on the basis of their impact on the practice of prosthodontic and restorative dentistry. The selection committee is comprised of the Chairperson and members of the Editorial Council Awards and Grants Committee.

The winners will be notified by March 15, 2010. Each recipient will receive a check and a plaque that, if the recipient so chooses, will be presented at a meeting of one of the JPD’s sponsoring organizations.

The Editor and members of the Editorial Council are not eligible for the award.

Clinical ImplicationsDespite immediate dentin sealing that resulted in high bond strengths for both adhesives, the marginal microleakage was not improved. The total-etch and self-etch adhesives evaluated have a significant effect on immediate dentin sealing.

Statement of problem. Sealing ability and bond strengths of total-etch and self-etch dentin adhesives used for imme-diate dentin sealing have not been assessed and established.

Purpose. The purpose of this study was to determine the effectiveness of immediate dentin sealing (IDS) using total-etch or self-etch dentin adhesives on microleakage and microtensile bond strength.

Material and methods. Twenty recently extracted molars were selected, and standard MOD inlay preparations were made with the gingival margins located below the cemento-enamel junction. The teeth were assigned to 4 experi-mental groups (n=5) according to the indirect composite restoration cementation technique used: (1) immediate dentin sealing with Adper Single Bond (TEBI); (2) conventional adhesive cementation technique using Adper Single Bond (TEAI); (3) immediate dentin sealing using Adper Prompt L-Pop (SEBI); or (4) conventional adhesive cementa-tion technique using Adper Prompt L-Pop (SEAI). The restored teeth were thermal cycled 1,000 times between 5° and 55°C and then immersed in 50% ammoniacal silver nitrate. Three specimens per restoration were evaluated for microleakage, according to predefined scores, and submitted to Friedman’s test (α=.05). The specimens were then sectioned to obtain 0.8 ±0.2-mm-thick sticks (with n ranging from 32 to 57 specimens) and submitted to microtensile bond strength (µTBS) testing. The obtained data were submitted to 2-way ANOVA test (α=.05).

Results. None of the experimental groups demonstrated complete elimination of marginal microleakage. There were significant differences in microleakage of the tested adhesives (P>.001). IDS microleakage scores were similar to those obtained using the conventional cementation technique (CCT) for both adhesives. The highest mean bond strengths were obtained with TEBI (51.1 MPa), whereas SEAI showed the lowest mean bond strengths (1.7 MPa). IDS resulted in significantly higher bond strengths than CCT (P<.001).

Conclusions. Total-etch and self-etch adhesives have a significant effect on IDS. IDS resulted in high bond strengths for both adhesives; however, the microleakage was similar to that obtained with CCT. (J Prosthet Dent 2009;102:1-9)

The effect of immediate dentin sealing on the marginal adaptation and bond strengths of total-etch and self-etch adhesives

Sillas Duarte, Jr, DDS, MS, PhD,a Claudia Regina Buanain de Freitas, DDS, MS,b José Roberto Cury Saad, DDS, MS, PhD,c and Avishai Sadan, DMDd

School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio; Araraquara School of Dentistry, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil

aAssociate Professor, Department of Comprehensive Care, Case Western Reserve University.bPhD student, Department of Operative Dentistry, São Paulo State University.cAssociate Professor, Department of Operative Dentistry, São Paulo State University.dProfessor and Chairman, Department of Comprehensive Care, Case Western Reserve University.

2 Volume 102 Issue 1

The Journal of Prosthetic Dentistry

3July 2009

Duarte et alDuarte et al

Tooth-colored posterior direct esthetic restorations are affected by polymerization shrinkage,1 which may result in postoperative sensitivity and also in disruption of the bonded interface.2,3 To overcome these prob-lems, indirect restoration has been advocated, especially to restore deep preparations with gingival margins lo-cated in dentin.4,5 Unfortunately, the need to form a path of insertion with divergent preparation walls for indi-rect restorations exposes more dental tissue. In addition, the bond to the gingival walls was found to be less pre-dictible than the bond to axial walls in both in vitro6-8 and in vivo investiga-tions.7 The bonding system used also can positively or negatively affect the adhesion to dentin margins.9

Immediate dentin sealing (IDS) has been reported to increase the bond strengths of indirect restorations.10,11-15 Freshly prepared dentin is more permeable16,17; thus, it is more susceptible to bacterial contamination.18-22 The application of a dentin adhesive to freshly pre-pared dentin might seal and protect dentin against bacterial leakage.23-25 However, as the weak link of a bond-ed indirect restoration is located at the adhesive layer-dentin inter-face,26-31 microleakage remains a con-cern,10,25,32-37 especially under thermal or occlusal stress.38,39

Sealing ability and bond strengths of total-etch and self-etch dentin ad-hesives used for IDS have not been established. The objective of the pres-

ent study was to evaluate the effect of immediate dentin sealing (IDS) on microtensile bond strengths and microleakage using a total-etch and a self-etch dentin adhesive. The null hypotheses tested in this study were: (1) different adhesives used for IDS do not influence marginal microleak-age, and (2) there is no difference in microtensile bond strength when dif-ferent adhesives are used for IDS.

MATERIAL AND METHODS

Twenty freshly extracted caries-free human third molars were selected for the present study after examina-tion with a stereomicroscope (Carl Zeiss Microimaging, Inc, Thornwood, NY) at x20 magnification to detect possible enamel cracks or fissures, and stored in 0.5% chloramine (Fish-er Scientific, Pittsburg, Pa) at 4°C. Twenty standardized MOD Class II preparations for indirect compos-ite restorations were prepared with 15-degree gingival-occlusal diver-gence.38 Standardized preparations were completed with a diamond rota-ry cutting instrument (#3131; KG So-rensen, Barueri, São Paulo, Brazil) in a high-speed handpiece with copious water cooling. After every 5 prepara-tions, the diamond rotary cutting in-strument was discarded and replaced with a new one. Each standardized preparation had the following dimen-sions: buccal-lingual extension, 6.0 mm; pulpal floor depth, 2.5 mm; axial wall extension, 2.5 mm; occlusal-gin-

gival extension, 6.0 mm. The gingival walls were placed below the cemento- enamel junction (CEJ) (Fig. 1). All preparations were examined under x20 magnification for possible cracks or fissures. A digital caliper (Mitutoyo Corp, Kawasaki, Japan) and a peri-odontal probe were used to examine the preparation dimensions, and if any deviation from the standard prep-aration design occurred, the tooth was discarded and another specimen was prepared.

The preparations were assigned to 4 experimental groups (n=5), accord-ing to the hard tissue hybridization and cementation technique used. That is, the internal hard tissues of the preparations were immediately sealed before impressions and before ce-mentation using a total-etch adhesive (TEBI, Adper Single Bond; 3M ESPE, St. Paul, Minn) or self-etch adhe-sive (SEBI, Adper Prompt L-Pop; 3M ESPE), while in groups TEAI and SEAI, the preparations were sealed only be-fore the cementation with total-etch and self-etch adhesives, respectively. All materials were used according to the manufacturer’s instructions (Ta-ble I).

TEBI group: Total-etch adhesive, Ad-per Single Bond, before impression

The preparations were acid-etched with 35% phosphoric acid for 15 sec-onds (ScotchBond Etchant; 3M ESPE), rinsed with water for 10 seconds, blot dried using a cotton pellet to leave the

1 A, Occlusal view of inlay preparation. B, Cross-sectioned view of inlay preparation.

A B

Table I. Restorative materials used

surfaces moist (glistening), and then 2-3 layers of Adper Single Bond (3M ESPE) were applied. The applied ad-hesive was gently agitated for 15 sec-onds using a fully saturated applica-tor. The solvent was evaporated for 5 seconds and light polymerized for 10 seconds. For each prepared tooth (in

all groups), an acrylic resin (Duralay; Reliance Dental Mfg Co, Worth, Ill) custom tray was fabricated to facili-tate impression procedures. The cus-tom tray was coated with a thin layer of tray adhesive (Caulk Tray Adhesive; Dentsply Caulk, Milford, Del) and al-lowed to air dry for 5 minutes. Mixed

vinyl polysiloxane impression mate-rial (Aquasil ULV; Dentsply De Trey GmbH, Konstanz, Germany) was ap-plied to both the cavity preparation and the custom tray. The specimens were immediately inserted into the custom acrylic tray. After the impres-sion material had polymerized, the

Bis-GMA, HEMA, dimethacrylates, ethanol,

water, photoinitiator system, methacrylate functional copolymer of polyacrylic and polyitaconic acids,

5-nm silica particles(batch #3HT)

Methacrylate phosphoric ester, bis-GMA,

camphorquinone, 2-hydroxyethyl

methacrylate (HEMA), water, polyalkenoic acid

copolymer stabilizers(batch #133511)

Bis-GMA, TEGDMA polymer, zirconia/

silica filler, benzoyl peroxide(batch #CWCX)

UDMA, decanediol dimethacrylate,

bis-GMA, barium glass, mixed oxide,

silicon dioxide(batch #D34837)

Adper SingleBond

Adper PromptL-Pop

RelyX ARCAdhesiveCement

TargisCeromerSystem

Bis-GMA: bisphenol-A-diglycidylether dimethacrylate; HEMA: 2-hydroxyethyl methacrylate; TEGMA: triethylene glycol dimethacrylate;UDMA: urethane dimethacrylate

Composition

3M ESPE,St. Paul, Minn

3M ESPE

3M ESPE

Ivoclar Vivadent,Schaan,

Liechtenstein

Manufacturer

1. Apply Scotchbond Etchant to dentin. Wait 15 s and rinsefor 10 s. Blot excess water using cotton pellet withoutdehydrating dentin. Surface should appear glisteningwithout pooling of water.

2. Immediately after blotting, apply 2-3 consecutive coats ofadhesive for 15 s with gentle agitation using fully saturatedapplicator. Gently air thin for 5 s to evaporate solvent.Light polymerize for 10 s.

1. Apply adhesive to entire surface of cavity, rubbing insolution with moderate finger pressure for 15 s. Use gentlestream of air to thoroughly dry adhesive to thin film.

2. Apply second coat of adhesive that does not need to bemassaged into surface. Again, use gentle stream of air tothoroughly dry adhesive to thin film. Light polymerize for 10 s.

1. Dispense cement onto mixing pad and mix for 10 s.Apply thin layer of cement onto preparation.

2. Slowly seat inlay/onlay. While holding in place, removeexcess cement immediately after seating.

3. Light polymerize margins for 40 s.

1. Incrementally add Targis onto stone cast in 4 layers.Prepolymerize each layer with halogen light source (TargisQuick; Ivoclar Vivadent) for 10 s.

2. Apply layer of Targis Gel (Ivoclar Vivadent) onto definitiverestoration to inhibit oxygen layer formation.

3. Postpolymerize (Targis Power Oven; Ivoclar Vivadent)definitive restoration at 90°C for 25 min.

Application TechniqueMaterial



3July 2009


Tooth-colored posterior direct esthetic restorations are affected by polymerization shrinkage,1 which may result in postoperative sensitivity and also in disruption of the bonded interface.2,3 To overcome these prob-lems, indirect restoration has been advocated, especially to restore deep preparations with gingival margins lo-cated in dentin.4,5 Unfortunately, the need to form a path of insertion with divergent preparation walls for indi-rect restorations exposes more dental tissue. In addition, the bond to the gingival walls was found to be less pre-dictible than the bond to axial walls in both in vitro6-8 and in vivo investiga-tions.7 The bonding system used also can positively or negatively affect the adhesion to dentin margins.9

Immediate dentin sealing (IDS) has been reported to increase the bond strengths of indirect restorations.10,11-15 Freshly prepared dentin is more permeable16,17; thus, it is more susceptible to bacterial contamination.18-22 The application of a dentin adhesive to freshly pre-pared dentin might seal and protect dentin against bacterial leakage.23-25 However, as the weak link of a bond-ed indirect restoration is located at the adhesive layer-dentin inter-face,26-31 microleakage remains a con-cern,10,25,32-37 especially under thermal or occlusal stress.38,39

Sealing ability and bond strengths of total-etch and self-etch dentin ad-hesives used for IDS have not been established. The objective of the pres-

ent study was to evaluate the effect of immediate dentin sealing (IDS) on microtensile bond strengths and microleakage using a total-etch and a self-etch dentin adhesive. The null hypotheses tested in this study were: (1) different adhesives used for IDS do not influence marginal microleak-age, and (2) there is no difference in microtensile bond strength when dif-ferent adhesives are used for IDS.

MATERIAL AND METHODS

Twenty freshly extracted caries-free human third molars were selected for the present study after examina-tion with a stereomicroscope (Carl Zeiss Microimaging, Inc, Thornwood, NY) at x20 magnification to detect possible enamel cracks or fissures, and stored in 0.5% chloramine (Fish-er Scientific, Pittsburg, Pa) at 4°C. Twenty standardized MOD Class II preparations for indirect compos-ite restorations were prepared with 15-degree gingival-occlusal diver-gence.38 Standardized preparations were completed with a diamond rota-ry cutting instrument (#3131; KG So-rensen, Barueri, São Paulo, Brazil) in a high-speed handpiece with copious water cooling. After every 5 prepara-tions, the diamond rotary cutting in-strument was discarded and replaced with a new one. Each standardized preparation had the following dimen-sions: buccal-lingual extension, 6.0 mm; pulpal floor depth, 2.5 mm; axial wall extension, 2.5 mm; occlusal-gin-

gival extension, 6.0 mm. The gingival walls were placed below the cemento- enamel junction (CEJ) (Fig. 1). All preparations were examined under x20 magnification for possible cracks or fissures. A digital caliper (Mitutoyo Corp, Kawasaki, Japan) and a peri-odontal probe were used to examine the preparation dimensions, and if any deviation from the standard prep-aration design occurred, the tooth was discarded and another specimen was prepared.

The preparations were assigned to 4 experimental groups (n=5), accord-ing to the hard tissue hybridization and cementation technique used. That is, the internal hard tissues of the preparations were immediately sealed before impressions and before ce-mentation using a total-etch adhesive (TEBI, Adper Single Bond; 3M ESPE, St. Paul, Minn) or self-etch adhe-sive (SEBI, Adper Prompt L-Pop; 3M ESPE), while in groups TEAI and SEAI, the preparations were sealed only be-fore the cementation with total-etch and self-etch adhesives, respectively. All materials were used according to the manufacturer’s instructions (Ta-ble I).

TEBI group: Total-etch adhesive, Ad-per Single Bond, before impression

The preparations were acid-etched with 35% phosphoric acid for 15 sec-onds (ScotchBond Etchant; 3M ESPE), rinsed with water for 10 seconds, blot dried using a cotton pellet to leave the

1 A, Occlusal view of inlay preparation. B, Cross-sectioned view of inlay preparation.

A B

Table I. Restorative materials used

surfaces moist (glistening), and then 2-3 layers of Adper Single Bond (3M ESPE) were applied. The applied ad-hesive was gently agitated for 15 sec-onds using a fully saturated applica-tor. The solvent was evaporated for 5 seconds and light polymerized for 10 seconds. For each prepared tooth (in

all groups), an acrylic resin (Duralay; Reliance Dental Mfg Co, Worth, Ill) custom tray was fabricated to facili-tate impression procedures. The cus-tom tray was coated with a thin layer of tray adhesive (Caulk Tray Adhesive; Dentsply Caulk, Milford, Del) and al-lowed to air dry for 5 minutes. Mixed

vinyl polysiloxane impression mate-rial (Aquasil ULV; Dentsply De Trey GmbH, Konstanz, Germany) was ap-plied to both the cavity preparation and the custom tray. The specimens were immediately inserted into the custom acrylic tray. After the impres-sion material had polymerized, the

Bis-GMA, HEMA, dimethacrylates, ethanol,

water, photoinitiator system, methacrylate functional copolymer of polyacrylic and polyitaconic acids,

5-nm silica particles(batch #3HT)

Methacrylate phosphoric ester, bis-GMA,

camphorquinone, 2-hydroxyethyl

methacrylate (HEMA), water, polyalkenoic acid

copolymer stabilizers(batch #133511)

Bis-GMA, TEGDMA polymer, zirconia/

silica filler, benzoyl peroxide(batch #CWCX)

UDMA, decanediol dimethacrylate,

bis-GMA, barium glass, mixed oxide,

silicon dioxide(batch #D34837)

Adper SingleBond

Adper PromptL-Pop

RelyX ARCAdhesiveCement

TargisCeromerSystem

Bis-GMA: bisphenol-A-diglycidylether dimethacrylate; HEMA: 2-hydroxyethyl methacrylate; TEGMA: triethylene glycol dimethacrylate;UDMA: urethane dimethacrylate

Composition

3M ESPE,St. Paul, Minn

3M ESPE

3M ESPE

Ivoclar Vivadent,Schaan,

Liechtenstein

Manufacturer

1. Apply Scotchbond Etchant to dentin. Wait 15 s and rinsefor 10 s. Blot excess water using cotton pellet withoutdehydrating dentin. Surface should appear glisteningwithout pooling of water.

2. Immediately after blotting, apply 2-3 consecutive coats ofadhesive for 15 s with gentle agitation using fully saturatedapplicator. Gently air thin for 5 s to evaporate solvent.Light polymerize for 10 s.

1. Apply adhesive to entire surface of cavity, rubbing insolution with moderate finger pressure for 15 s. Use gentlestream of air to thoroughly dry adhesive to thin film.

2. Apply second coat of adhesive that does not need to bemassaged into surface. Again, use gentle stream of air tothoroughly dry adhesive to thin film. Light polymerize for 10 s.

1. Dispense cement onto mixing pad and mix for 10 s.Apply thin layer of cement onto preparation.

2. Slowly seat inlay/onlay. While holding in place, removeexcess cement immediately after seating.

3. Light polymerize margins for 40 s.

1. Incrementally add Targis onto stone cast in 4 layers.Prepolymerize each layer with halogen light source (TargisQuick; Ivoclar Vivadent) for 10 s.

2. Apply layer of Targis Gel (Ivoclar Vivadent) onto definitiverestoration to inhibit oxygen layer formation.

3. Postpolymerize (Targis Power Oven; Ivoclar Vivadent)definitive restoration at 90°C for 25 min.

Application TechniqueMaterial



5July 2009


specimens were removed from the tray and thoroughly rinsed in running water for 1 minute. The teeth were re-stored with a provisional restorative material (Fermit; Ivoclar Vivadent, Schaan, Liechtenstein) and stored in distilled water at 37°C for 7 days (un-til the cementation of the inlays).

The impressions were vacuum poured in type IV die stone (GC Fu-jirock EP; GC America, Alsip, Ill). The stone casts were coated with 2 layers of separator (Targis Model Separator; Ivoclar Vivadent). The indirect cer-omer inlays (Targis system; Ivoclar Vi-vadent) were fabricated as described in Table I. The inlay finishing and pol-ishing procedures were performed with aluminum-oxide discs (Sof-Lex XT; 3M ESPE). After 7 days, the in-terim restorations were removed and the sealed dentin was cleaned with pumice and water. The ceromer inlays were placed into the preparations and the marginal adaptation was evaluat-ed with a stereomicroscope under x10 magnification (Carl Zeiss Microimag-ing, Inc).

The intaglio surface of the resto-rations was treated with airborne-particle abrasion with 50-µm Al2O3 particles (Microetcher II; Danville Engineering, San Ramon, Calif ) for 10 seconds under a pressure of 50 psi at a 10-mm distance, rinsed with distilled water, and air dried. Subse-quently, a silane coupling agent (Ce-ramic Primer; 3M ESPE) was applied to the restoration’s intaglio surface, allowed to evaporate for 3 minutes, and air dried for 30 seconds.40 A thin layer of the dentin adhesive (Adper Single Bond; 3M ESPE) was applied to the intaglio surface of the restora-tions without light polymerization be-fore the cementation. 24

The preparations were acid etched with 35% phosphoric acid for 15 seconds, rinsed with water for 10 seconds, blot dried before the appli-cation of 2-3 layers of Adper Single Bond, agitated for 15 seconds, then the solvent was allowed to evaporate for 5 seconds, and the preparation was light polymerized for 10 seconds. The

resin cement (RelyX ARC; 3M ESPE) was dispensed, mixed, and applied to both the internal surface of the res-toration and the cavity preparation before seating the inlay. The ceromer inlay was seated in the preparation under a 1-kg weight, while the excess cement was carefully removed from the margins with disposable sponges. All of the margins were polymerized for 40 seconds with a light-polymer-ization unit (XL3000 light; 3M ESPE) with a light output of 600 mW/cm2 constantly monitored with a radiom-eter (Demetron Halogen Radiometer; Kerr Corp, Orange, Calif ). The mar-gins of the restorations were finished with aluminum-oxide discs (Sof-Lex XT; 3M ESPE) under x10 magnifica-tion. The restored teeth were stored in 37°C distilled water for 24 hours.

TEAI group: Total-etch adhesive, Ad-per Single Bond, after impression

The preparations were neither immediately acid etched nor resin sealed, and were instead cemented with the conventional cementation technique (CCT). Vinyl polysiloxane impressions were made as described previously. After the impression mate-rial had polymerized, the specimens were removed from the tray and thor-oughly rinsed in running water for 1 minute. The teeth were restored with a provisional restorative material (Fer-mit; Ivoclar Vivadent) and stored in distilled water at 37°C for 7 days (un-til the cementation of the inlays). The impressions were vacuum poured, die spacer was added, and the ceromer inlays were fabricated. Next, the inter-im restorations were removed and the preparation was cleaned with pumice and water. The ceromer inlays were placed into the preparations, and the marginal adaptation was evaluated with a stereomicroscope under x10 magnification (Carl Zeiss Microimag-ing, Inc).

The intaglio surface of the restora-tions was airborne-particle abraded with 50-µm Al2O3 particles (Micro-etcher II; Danville Engineering) for 10

seconds under a pressure of 50 psi at a 10-mm distance, rinsed with distilled water, air dried, and silanated. A thin layer of the dentin adhesive (Adper Single Bond; 3M ESPE) was applied to the internal surface of the restora-tions, without light polymerization before the cementation.24

The preparations were acid etched with 35% phosphoric acid for 15 seconds (ScotchBond Etchant; 3M ESPE), rinsed with water for 10 sec-onds, blot dried using a cotton pellet to leave the surfaces moist (glisten-ing), and then 2-3 layers of Adper Single Bond (3M ESPE) were applied. The applied adhesive was agitated for 15 seconds using a fully saturated applicator. The solvent was allowed to evaporate for 5 seconds and light polymerized for 10 seconds. The resin cement (RelyX ARC; 3M ESPE) was dispensed, mixed, and applied to both the intaglio surface of the res-toration and the cavity preparation before seating the inlay. The ceromer inlay was seated in the preparation as described previously, and all the mar-gins were polymerized for 40 seconds (XL3000 light; 3M ESPE). The mar-gins of the restorations were finished with aluminum-oxide discs (Sof-Lex XT; 3M ESPE) under x10 magnifica-tion. The restored teeth were stored in 37°C distilled water for 24 hours.

SEBI group: Self-etch adhesive, Adper Prompt L-Pop, before impression

Dry, smear layer-covered dentin was immediately sealed with self-etch adhesive (Adper Prompt L-Pop; 3M ESPE). The adhesive was applied to the entire surface of the cavity while being agitated with moderate finger pressure for 15 seconds. A gentle stream of air was applied to thor-oughly dry the adhesive to a thin film. A second coat of adhesive was ap-plied, followed by a gentle stream of air to thoroughly dry the adhesive to a thin film. The adhesive was then light polymerized for 10 seconds (XL3000 light; 3M ESPE). Impressions were made, and then the teeth were pro-

visionally restored and stored in dis-tilled water at 37°C for 7 days. The casts were made, die spacer was added, and the inlays were fabricated as described previously. The intaglio surface of the restoration was treated with airborne-particle abrasion with 50-µm Al2O3 particles (Microetcher II; Danville Engineering) for 10 sec-onds, rinsed with distilled water, air dried, and silanated. No adhesive was applied to the intaglio of the restora-tion because of the acidic pH of the self-etch adhesive.

The interim restoration was re-moved, and the preparations were resealed with the self-etch adhesive (Adper Prompt L-Pop; 3M ESPE) and light polymerized for 10 seconds. The resin cement (Rely X ARC; 3M ESPE) was dispensed, mixed, and applied to both the internal surface of the res-toration and the cavity preparation before seating the inlay. The ceromer inlay was seated in the preparation under a 1-kg weight, and the excess ce-ment was carefully removed from the margins with disposable sponges. All of the margins were polymerized for 40 seconds (XL3000 light; 3M ESPE), and the margins of the restorations were finished with aluminum-oxide discs (Sof-Lex XT; 3M ESPE). The re-stored teeth were stored in 37°C dis-tilled water for 24 hours.

SEAI group: Self-etch adhesive, Adper Prompt L-Pop, after impression

Dry, smear layer-covered dentin was not previously sealed with Adper Prompt L-Pop (3M ESPE). Instead, impressions were made, casts were made, die spacer was added, and the inlays were fabricated. The teeth were restored with a provisional restorative material (Fermit; Ivoclar Vivadent) and stored in distilled water at 37°C for 7 days.

The provisional restoration was removed, and the preparations were sealed with self-etch adhesive (Adper Prompt L-Pop; 3M ESPE). The adhe-sive was applied to the entire surface of the cavity, rubbing in the solution with moderate finger pressure for 15 seconds. A gentle stream of air was applied to thoroughly dry the adhe-sive to a thin film. A second coat of adhesive was applied, followed by a gentle stream of air to thoroughly dry the adhesive to a thin film. The ad-hesive was then light polymerized for 10 seconds. The resin cement (Rely X ARC; 3M ESPE) was dispensed, mixed, and applied to both the intaglio sur-face of the restoration and the cavity preparation before seating the inlay. The cementation and finishing were

performed as described previously.All of the specimens were cycled

for 1000 thermal cycles between water baths held at 5oC/55oC, using a 30-second dwell time. Next, the specimens were coated with 2 layers of nail polish (Vinyl shine nail polish; Rimmel London, London, UK), except for a 2.0-mm rim around the restora-tion, to allow contact of the leakage-tracing agent with the margins of the restoration. The specimens were then immersed in an aqueous solution of 50 wt% ammoniacal silver nitrate (pH=9.5) for 24 hours, followed by 8 hours in a photo-developing solution (Eastman Kodak Co, Rochester, NY) to permit reduction of the diammine silver ions to metallic silver grains.41 The specimens were retrieved from the photo-developing solution and washed in running water for 1 minute. The nail polish was carefully removed with a #15 scalpel (Miltex Instruments Co, York, Pa) and the specimens were sectioned through the restoration with a precision, water-cooled, slow-speed diamond saw (IsoMet 1000; Buehler Ltd, Lake Bluff, Ill). Three 0.8 ±0.2-mm-thick slabs from the center of the restoration were generated (Fig. 2, A). The slabs were analyzed with a stereomicroscope at x30 magnifica-tion and scored by 2 examiners for

2 A, Specimen preparation for microleakage evaluation. B, Microleakage scores.A B



5July 2009


specimens were removed from the tray and thoroughly rinsed in running water for 1 minute. The teeth were re-stored with a provisional restorative material (Fermit; Ivoclar Vivadent, Schaan, Liechtenstein) and stored in distilled water at 37°C for 7 days (un-til the cementation of the inlays).

The impressions were vacuum poured in type IV die stone (GC Fu-jirock EP; GC America, Alsip, Ill). The stone casts were coated with 2 layers of separator (Targis Model Separator; Ivoclar Vivadent). The indirect cer-omer inlays (Targis system; Ivoclar Vi-vadent) were fabricated as described in Table I. The inlay finishing and pol-ishing procedures were performed with aluminum-oxide discs (Sof-Lex XT; 3M ESPE). After 7 days, the in-terim restorations were removed and the sealed dentin was cleaned with pumice and water. The ceromer inlays were placed into the preparations and the marginal adaptation was evaluat-ed with a stereomicroscope under x10 magnification (Carl Zeiss Microimag-ing, Inc).

The intaglio surface of the resto-rations was treated with airborne-particle abrasion with 50-µm Al2O3 particles (Microetcher II; Danville Engineering, San Ramon, Calif ) for 10 seconds under a pressure of 50 psi at a 10-mm distance, rinsed with distilled water, and air dried. Subse-quently, a silane coupling agent (Ce-ramic Primer; 3M ESPE) was applied to the restoration’s intaglio surface, allowed to evaporate for 3 minutes, and air dried for 30 seconds.40 A thin layer of the dentin adhesive (Adper Single Bond; 3M ESPE) was applied to the intaglio surface of the restora-tions without light polymerization be-fore the cementation. 24

The preparations were acid etched with 35% phosphoric acid for 15 seconds, rinsed with water for 10 seconds, blot dried before the appli-cation of 2-3 layers of Adper Single Bond, agitated for 15 seconds, then the solvent was allowed to evaporate for 5 seconds, and the preparation was light polymerized for 10 seconds. The

resin cement (RelyX ARC; 3M ESPE) was dispensed, mixed, and applied to both the internal surface of the res-toration and the cavity preparation before seating the inlay. The ceromer inlay was seated in the preparation under a 1-kg weight, while the excess cement was carefully removed from the margins with disposable sponges. All of the margins were polymerized for 40 seconds with a light-polymer-ization unit (XL3000 light; 3M ESPE) with a light output of 600 mW/cm2 constantly monitored with a radiom-eter (Demetron Halogen Radiometer; Kerr Corp, Orange, Calif ). The mar-gins of the restorations were finished with aluminum-oxide discs (Sof-Lex XT; 3M ESPE) under x10 magnifica-tion. The restored teeth were stored in 37°C distilled water for 24 hours.

TEAI group: Total-etch adhesive, Ad-per Single Bond, after impression

The preparations were neither immediately acid etched nor resin sealed, and were instead cemented with the conventional cementation technique (CCT). Vinyl polysiloxane impressions were made as described previously. After the impression mate-rial had polymerized, the specimens were removed from the tray and thor-oughly rinsed in running water for 1 minute. The teeth were restored with a provisional restorative material (Fer-mit; Ivoclar Vivadent) and stored in distilled water at 37°C for 7 days (un-til the cementation of the inlays). The impressions were vacuum poured, die spacer was added, and the ceromer inlays were fabricated. Next, the inter-im restorations were removed and the preparation was cleaned with pumice and water. The ceromer inlays were placed into the preparations, and the marginal adaptation was evaluated with a stereomicroscope under x10 magnification (Carl Zeiss Microimag-ing, Inc).

The intaglio surface of the restora-tions was airborne-particle abraded with 50-µm Al2O3 particles (Micro-etcher II; Danville Engineering) for 10

seconds under a pressure of 50 psi at a 10-mm distance, rinsed with distilled water, air dried, and silanated. A thin layer of the dentin adhesive (Adper Single Bond; 3M ESPE) was applied to the internal surface of the restora-tions, without light polymerization before the cementation.24

The preparations were acid etched with 35% phosphoric acid for 15 seconds (ScotchBond Etchant; 3M ESPE), rinsed with water for 10 sec-onds, blot dried using a cotton pellet to leave the surfaces moist (glisten-ing), and then 2-3 layers of Adper Single Bond (3M ESPE) were applied. The applied adhesive was agitated for 15 seconds using a fully saturated applicator. The solvent was allowed to evaporate for 5 seconds and light polymerized for 10 seconds. The resin cement (RelyX ARC; 3M ESPE) was dispensed, mixed, and applied to both the intaglio surface of the res-toration and the cavity preparation before seating the inlay. The ceromer inlay was seated in the preparation as described previously, and all the mar-gins were polymerized for 40 seconds (XL3000 light; 3M ESPE). The mar-gins of the restorations were finished with aluminum-oxide discs (Sof-Lex XT; 3M ESPE) under x10 magnifica-tion. The restored teeth were stored in 37°C distilled water for 24 hours.

SEBI group: Self-etch adhesive, Adper Prompt L-Pop, before impression

Dry, smear layer-covered dentin was immediately sealed with self-etch adhesive (Adper Prompt L-Pop; 3M ESPE). The adhesive was applied to the entire surface of the cavity while being agitated with moderate finger pressure for 15 seconds. A gentle stream of air was applied to thor-oughly dry the adhesive to a thin film. A second coat of adhesive was ap-plied, followed by a gentle stream of air to thoroughly dry the adhesive to a thin film. The adhesive was then light polymerized for 10 seconds (XL3000 light; 3M ESPE). Impressions were made, and then the teeth were pro-

visionally restored and stored in dis-tilled water at 37°C for 7 days. The casts were made, die spacer was added, and the inlays were fabricated as described previously. The intaglio surface of the restoration was treated with airborne-particle abrasion with 50-µm Al2O3 particles (Microetcher II; Danville Engineering) for 10 sec-onds, rinsed with distilled water, air dried, and silanated. No adhesive was applied to the intaglio of the restora-tion because of the acidic pH of the self-etch adhesive.

The interim restoration was re-moved, and the preparations were resealed with the self-etch adhesive (Adper Prompt L-Pop; 3M ESPE) and light polymerized for 10 seconds. The resin cement (Rely X ARC; 3M ESPE) was dispensed, mixed, and applied to both the internal surface of the res-toration and the cavity preparation before seating the inlay. The ceromer inlay was seated in the preparation under a 1-kg weight, and the excess ce-ment was carefully removed from the margins with disposable sponges. All of the margins were polymerized for 40 seconds (XL3000 light; 3M ESPE), and the margins of the restorations were finished with aluminum-oxide discs (Sof-Lex XT; 3M ESPE). The re-stored teeth were stored in 37°C dis-tilled water for 24 hours.

SEAI group: Self-etch adhesive, Adper Prompt L-Pop, after impression

Dry, smear layer-covered dentin was not previously sealed with Adper Prompt L-Pop (3M ESPE). Instead, impressions were made, casts were made, die spacer was added, and the inlays were fabricated. The teeth were restored with a provisional restorative material (Fermit; Ivoclar Vivadent) and stored in distilled water at 37°C for 7 days.

The provisional restoration was removed, and the preparations were sealed with self-etch adhesive (Adper Prompt L-Pop; 3M ESPE). The adhe-sive was applied to the entire surface of the cavity, rubbing in the solution with moderate finger pressure for 15 seconds. A gentle stream of air was applied to thoroughly dry the adhe-sive to a thin film. A second coat of adhesive was applied, followed by a gentle stream of air to thoroughly dry the adhesive to a thin film. The ad-hesive was then light polymerized for 10 seconds. The resin cement (Rely X ARC; 3M ESPE) was dispensed, mixed, and applied to both the intaglio sur-face of the restoration and the cavity preparation before seating the inlay. The cementation and finishing were

performed as described previously.All of the specimens were cycled

for 1000 thermal cycles between water baths held at 5oC/55oC, using a 30-second dwell time. Next, the specimens were coated with 2 layers of nail polish (Vinyl shine nail polish; Rimmel London, London, UK), except for a 2.0-mm rim around the restora-tion, to allow contact of the leakage-tracing agent with the margins of the restoration. The specimens were then immersed in an aqueous solution of 50 wt% ammoniacal silver nitrate (pH=9.5) for 24 hours, followed by 8 hours in a photo-developing solution (Eastman Kodak Co, Rochester, NY) to permit reduction of the diammine silver ions to metallic silver grains.41 The specimens were retrieved from the photo-developing solution and washed in running water for 1 minute. The nail polish was carefully removed with a #15 scalpel (Miltex Instruments Co, York, Pa) and the specimens were sectioned through the restoration with a precision, water-cooled, slow-speed diamond saw (IsoMet 1000; Buehler Ltd, Lake Bluff, Ill). Three 0.8 ±0.2-mm-thick slabs from the center of the restoration were generated (Fig. 2, A). The slabs were analyzed with a stereomicroscope at x30 magnifica-tion and scored by 2 examiners for

2 A, Specimen preparation for microleakage evaluation. B, Microleakage scores.A B



7July 2009


the degree of dye penetration along the dentin walls (mesial and distal gingival margins), according to the following scores42: score 0, no mar-ginal leakage; score 1, silver nitrate penetrates up to half the length of the gingival wall; score 2, silver nitrate penetrates beyond half the gingival wall length, without reaching the axial wall; score 3, silver nitrate penetrates along the gingival and axial walls to-wards the pulp (Fig. 2, B).

There were 5 teeth per group. Each tooth yielded 3 slabs for the scoring of microleakage. The marginal mi-croleakage of each slab was assessed for the mesial and distal margins of the restorations. Therefore, repeated measurements of microleakage scores were obtained from each tooth (3 slabs and measurements on the me-sial and distal margins, for 6 measure-ments per molar). Statistical analysis was performed with statistical soft-ware (SPSS 15; SPSS, Inc, Chicago, Ill). The data were analyzed with the Friedman’s test (α=.05) to evaluate different techniques of hybridization for indirect ceromer restorations, fol-

lowed by Wilcoxon post hoc tests.After microleakage evaluation,

each slab was again attached to a phe-nolic ring (Buehler Ltd), and a second set of sections, 0.8 ±0.2 mm thick, were cut perpendicular to the adhe-sive interface. Stick-shaped specimens with a rectangular sectional area of 0.8 ±0.2 mm were obtained from gin-gival and pulpal walls. Specimens with either inappropriate dimensions or uneven bonded interfaces that could not be aligned perpendicular to the tensile load were discarded; thus, the number of specimens for each group ranged from 32 to 57. The specimens were tested individually by attaching them to a microtensile jig using cyano-acrylate glue (Zapit; Dental Ventures of America, Inc, Corona, Calif ).43 The specimens were then submitted to a tension load using a universal test-ing machine (MTS 810; MTS Systems Corp, Eden Prairie, Minn) at 1.0 mm/min crosshead speed. A digital caliper (Mitutoyo Corp) with an accuracy of 0.001 mm was used to measure the depth and width of the bonded inter-face and calculate the bonding area in

millimeters. The load (in newtons, N) and the bonding surface area of the specimen were recorded, and micro-tensile bond strengths were calculat-ed in MPa. The fractured specimens were observed under a stereoscopic microscope under x40 magnification to classify the mode of failure as: (A) adhesive failure, (C) cohesive failure, or (M) mixed failure. Statistical analy-sis was performed using the same statistical software. Bond strength data obtained from the 4 experimen-tal groups were analyzed with a 2-way analysis of variance (ANOVA), with each tooth (mean microtensile bond strength testing from the number of beams retrieved from each tooth) used as a single measurement, yielding 5 measurements per group (α=.05). A 2-way ANOVA was computed with ad-hesive type and immediate or delayed sealing as the 2 factors (α=.05).

RESULTS

Table II represents repeated mea-surements of microleakage scores on each tooth (3 slabs and measurements

Table II. Microleakage scores

123

123

123

123

123

1

2

3

4

5

Specimen

111

313

333

133

133

Mesial

TEBI

Tooth

010

322

333

133

211

Distal

333

313

222

223

222

Mesial

TEAI

233

333

222231

112

Distal

333

333

333

333

333

Mesial

SEBI

333

333

333

333

333

Distal

333

333

333333

333

Mesial

SEAI

333

333

333

333

333

Distal

on the mesial and distal margins, for 6 measurements per molar). The analy-sis of microleakage scores was con-ducted for mesial and distal margins separately. Significant differences in marginal microleakage were observed for all experimental groups in both mesial (χ2=17.48, P<.001) and dis-tal margins (χ2=21.26, P<.001), and Wilcoxon tests were used to follow up this finding. A Bonferroni correction was applied and so all of the effects are reported at a 0.0125 level of sig-nificance. None of the experimental groups was capable of completely eliminating marginal microleakage. The immediate dentin sealing (IDS) microleakage scores were similar to those obtained from the conventional cementation technique for both Sin-

gle Bond (P=.287) and Prompt L-Pop (P=1.00) adhesives. However, differ-ent adhesive systems resulted in sig-nificant differences in microleakage at dentin margins (P<.001). The total-etch adhesive (Adper Single Bond) produced less microleakage than the all-in-one self-etch adhesive (Adper Prompt L-Pop).

Table III lists the microtensile bond strengths and standard deviations for the experimental groups. The highest mean bond strengths were obtained when a total-etch adhesive (Adper Single Bond) was used (TEBI, 51.1 MPa; TEAI, 40.7 MPa). The use of a self-etch adhesive (Adper Prompt L-Pop) for cementation of ceromer inlays resulted in significantly lower bond strengths (P<.001) than total-

etch adhesives, regardless of the ce-mentation technique (SEBI, 13.0 MPa; SEAI, 1.7 MPa).

Most of the failures observed in the total-etch groups were cohesive (TEBI, 58.1%; TEAI, 64.4%), whereas self-etch adhesive groups showed more adhesive failures (SEBI, 67.9%; SEAI, 87.8%). Spontaneous pretest debonding failures (PTF) were ob-served only for the groups in which self-etch adhesive was used. In those 2 groups (SEBI and SEAI), the pretest failures represented 48% and 86% of the total, respectively (Table III). Any specimen exhibiting PTF was counted as 0 MPa. When means were pooled for the cementation technique, im-mediate dentin sealing resulted in sig-nificantly higher bond strengths than

Table IV. Two-way analysis of variance (ANOVA) for cementation technique (immediate or delayed sealing) and adhesive type (total etch or self etch)

Table III. Mean microtensile bond strengths (SD) in MPa

1

2

3

4

5

Total

PTF/n

Means followed by different superscript letter are statistically different at P<.05. PTF/n: Number of pretest debond failures/total number of sticks prepared.

49.4 (13.7)

46.0 (15.1)

56.0 (11.0)

47.0 (12.7)

57.1 (12.1)

51.1 (5.1)a

0/32

TEBITooth

33.1 (11.8)

41.0 (12.2)

44.9 (18.2)

35.7 (18.3)

18.8 (16.1)

40.7 (6.4)b

0/45

TEAI

8.7 (12.1)

13.6 (9.0)

21.1 (9.6)

12.3 (17.8)

9.8 (15.4)

13.0 (5.0)c

27/56

SEBI

2.0 (4.2)

1.7 (3.6)

2.5 (5.5)

2.8 (8.4)

0.0 (0.0)

1.7 (1.1)d

42/49

SEAI

Cementation technique

Adhesive

Cementation technique x adhesive

Error

Corrected total

1

1

1

16

19

df

585

7426

1.053

374

8387

585

7426

1.05

23

Squares SquareSum of Mean

25.0

317.6

0.45

FSource

<.001

<.001

.84

P



7July 2009


the degree of dye penetration along the dentin walls (mesial and distal gingival margins), according to the following scores42: score 0, no mar-ginal leakage; score 1, silver nitrate penetrates up to half the length of the gingival wall; score 2, silver nitrate penetrates beyond half the gingival wall length, without reaching the axial wall; score 3, silver nitrate penetrates along the gingival and axial walls to-wards the pulp (Fig. 2, B).

There were 5 teeth per group. Each tooth yielded 3 slabs for the scoring of microleakage. The marginal mi-croleakage of each slab was assessed for the mesial and distal margins of the restorations. Therefore, repeated measurements of microleakage scores were obtained from each tooth (3 slabs and measurements on the me-sial and distal margins, for 6 measure-ments per molar). Statistical analysis was performed with statistical soft-ware (SPSS 15; SPSS, Inc, Chicago, Ill). The data were analyzed with the Friedman’s test (α=.05) to evaluate different techniques of hybridization for indirect ceromer restorations, fol-

lowed by Wilcoxon post hoc tests.After microleakage evaluation,

each slab was again attached to a phe-nolic ring (Buehler Ltd), and a second set of sections, 0.8 ±0.2 mm thick, were cut perpendicular to the adhe-sive interface. Stick-shaped specimens with a rectangular sectional area of 0.8 ±0.2 mm were obtained from gin-gival and pulpal walls. Specimens with either inappropriate dimensions or uneven bonded interfaces that could not be aligned perpendicular to the tensile load were discarded; thus, the number of specimens for each group ranged from 32 to 57. The specimens were tested individually by attaching them to a microtensile jig using cyano-acrylate glue (Zapit; Dental Ventures of America, Inc, Corona, Calif ).43 The specimens were then submitted to a tension load using a universal test-ing machine (MTS 810; MTS Systems Corp, Eden Prairie, Minn) at 1.0 mm/min crosshead speed. A digital caliper (Mitutoyo Corp) with an accuracy of 0.001 mm was used to measure the depth and width of the bonded inter-face and calculate the bonding area in

millimeters. The load (in newtons, N) and the bonding surface area of the specimen were recorded, and micro-tensile bond strengths were calculat-ed in MPa. The fractured specimens were observed under a stereoscopic microscope under x40 magnification to classify the mode of failure as: (A) adhesive failure, (C) cohesive failure, or (M) mixed failure. Statistical analy-sis was performed using the same statistical software. Bond strength data obtained from the 4 experimen-tal groups were analyzed with a 2-way analysis of variance (ANOVA), with each tooth (mean microtensile bond strength testing from the number of beams retrieved from each tooth) used as a single measurement, yielding 5 measurements per group (α=.05). A 2-way ANOVA was computed with ad-hesive type and immediate or delayed sealing as the 2 factors (α=.05).

RESULTS

Table II represents repeated mea-surements of microleakage scores on each tooth (3 slabs and measurements

Table II. Microleakage scores

123

123

123

123

123

1

2

3

4

5

Specimen

111

313

333

133

133

Mesial

TEBI

Tooth

010

322

333

133

211

Distal

333

313

222

223

222

Mesial

TEAI

233

333

222231

112

Distal

333

333

333

333

333

Mesial

SEBI

333

333

333

333

333

Distal

333

333

333333

333

Mesial

SEAI

333

333

333

333

333

Distal

on the mesial and distal margins, for 6 measurements per molar). The analy-sis of microleakage scores was con-ducted for mesial and distal margins separately. Significant differences in marginal microleakage were observed for all experimental groups in both mesial (χ2=17.48, P<.001) and dis-tal margins (χ2=21.26, P<.001), and Wilcoxon tests were used to follow up this finding. A Bonferroni correction was applied and so all of the effects are reported at a 0.0125 level of sig-nificance. None of the experimental groups was capable of completely eliminating marginal microleakage. The immediate dentin sealing (IDS) microleakage scores were similar to those obtained from the conventional cementation technique for both Sin-

gle Bond (P=.287) and Prompt L-Pop (P=1.00) adhesives. However, differ-ent adhesive systems resulted in sig-nificant differences in microleakage at dentin margins (P<.001). The total-etch adhesive (Adper Single Bond) produced less microleakage than the all-in-one self-etch adhesive (Adper Prompt L-Pop).

Table III lists the microtensile bond strengths and standard deviations for the experimental groups. The highest mean bond strengths were obtained when a total-etch adhesive (Adper Single Bond) was used (TEBI, 51.1 MPa; TEAI, 40.7 MPa). The use of a self-etch adhesive (Adper Prompt L-Pop) for cementation of ceromer inlays resulted in significantly lower bond strengths (P<.001) than total-

etch adhesives, regardless of the ce-mentation technique (SEBI, 13.0 MPa; SEAI, 1.7 MPa).

Most of the failures observed in the total-etch groups were cohesive (TEBI, 58.1%; TEAI, 64.4%), whereas self-etch adhesive groups showed more adhesive failures (SEBI, 67.9%; SEAI, 87.8%). Spontaneous pretest debonding failures (PTF) were ob-served only for the groups in which self-etch adhesive was used. In those 2 groups (SEBI and SEAI), the pretest failures represented 48% and 86% of the total, respectively (Table III). Any specimen exhibiting PTF was counted as 0 MPa. When means were pooled for the cementation technique, im-mediate dentin sealing resulted in sig-nificantly higher bond strengths than

Table IV. Two-way analysis of variance (ANOVA) for cementation technique (immediate or delayed sealing) and adhesive type (total etch or self etch)

Table III. Mean microtensile bond strengths (SD) in MPa

1

2

3

4

5

Total

PTF/n

Means followed by different superscript letter are statistically different at P<.05. PTF/n: Number of pretest debond failures/total number of sticks prepared.

49.4 (13.7)

46.0 (15.1)

56.0 (11.0)

47.0 (12.7)

57.1 (12.1)

51.1 (5.1)a

0/32

TEBITooth

33.1 (11.8)

41.0 (12.2)

44.9 (18.2)

35.7 (18.3)

18.8 (16.1)

40.7 (6.4)b

0/45

TEAI

8.7 (12.1)

13.6 (9.0)

21.1 (9.6)

12.3 (17.8)

9.8 (15.4)

13.0 (5.0)c

27/56

SEBI

2.0 (4.2)

1.7 (3.6)

2.5 (5.5)

2.8 (8.4)

0.0 (0.0)

1.7 (1.1)d

42/49

SEAI

Cementation technique

Adhesive

Cementation technique x adhesive

Error

Corrected total

1

1

1

16

19

df

585

7426

1.053

374

8387

585

7426

1.05

23

Squares SquareSum of Mean

25.0

317.6

0.45

FSource

<.001

<.001

.84

P



9July 2009


those obtained with the conventional cementation technique (P<.001) (Ta-ble IV). Therefore, there were signifi-cant differences between the tested cementation techniques. The interac-tion effect of cementation technique versus adhesive systems was not sig-nificant (P=84). The differences in overall bond strengths which related to the cementation techniques did not depend on the adhesive system; that is, the same cementation tech-nique differences were found for both the total-etch adhesive group and the self-etch adhesive group.

DISCUSSION

This study shows that while imme-diate dentin sealing enhanced bond strengths for both tested adhesives, it did not improve the marginal microleakage for indirect restorations. Thus, both hypotheses were rejected, since different adhesives produced sig-nificantly different scores for marginal microleakage and differences in bond strengths. Marginal sealing is impera-tive for long-term success of any in-direct restoration. In contrast, adhe-sive failure at the restoration margins can compromise the longevity of a restoration.18,39 If an adhesive failure occurs, the patient might experience postoperative sensitivity,20 recurrent caries,22 and pathologic alterations of the pulp.37 Two adhesive systems were evaluated in the present study: a total-etch (Adper Single Bond; 3M ESPE) and a self-etch (Adper Prompt L-Pop; 3M ESPE) adhesive system. There was a significant difference in the performance of the tested adhe-sive systems for microleakage and microtensile bond strength (Tables II and III).

Adper Prompt L-Pop is consid-ered a strong all-in-one self-etch ad-hesive.19 Its monomer initially has a pH as low as 1.0.26 After application of the adhesive, collagen fibers are exposed, and the hydroxyapatite is partially removed, but traces of the smear layer remain.27 The water pres-ent within dentin and in the adhesive

may not be completely removed by solvent evaporation. As a result, wa-ter becomes trapped in the micro-channels among the collagen fibrils, resulting in incomplete polymeriza-tion.28 The hybrid layer might show areas with minimal conversion inside of the polymeric matrix, with conse-quent nanoleakage.26 In addition, ad-verse chemical interaction was found when 1-step self-etch adhesives were bonded to dual-polymerizing com-posite resins.29,35 Therefore, the in-compatibility of acidic adhesive and dual-polymerizing composite resin may explain not only the high micro-leakage scores obtained for Adper Prompt L-Pop, but also the low bond strengths.

The total-etch adhesive (Adper Single Bond; 3M ESPE) showed a more favorable behavior than the self-etch adhesive (Adper Prompt L-Pop). Aging has been shown not to influence bond strengths of Adper Single Bond, regardless of the bonded walls (axial or gingival).9 However, this outcome should be interpreted with caution, since in vivo, the bond to gingival walls is significantly more subject to failure than the other prep-aration walls.7 Adper Single Bond has been reported to produce adequate dentin sealing30 and reduce dentin permeability,17 but marginal micro-leakage was not completely eliminat-ed. Some porosity within the hybrid layer created by Single Bond recently was observed.25 In addition, out-ward fluid flow is expected to occur with total-etch adhesives, even after bonding.36 The inward and outward fluid shifts create water trees, which can contribute to degradation of the resin-bonded interfaces.31

No difference was observed in mi-croleakage scores if the dentin was hy-bridized immediately after preparation or just before cementation, for both tested adhesives (Table II). However, significant differences were found for µTBS when immediate dentin sealing was used. The findings showed high-er bond strengths with IDS for both adhesive systems, particularly for the

total-etch adhesive (Table III). Im-mediate dentin sealing (IDS) is pur-ported to protect the exposed dentin after preparation.12,15,33 The appli-cation of total-etch adhesive12,23,33 or dentin adhesive associated with low-viscosity resin10,13,15 has been ad-vocated to enhance bond strengths. Most of the studies are consistent in showing that IDS produces higher bond strengths than do conventional cementation techniques, with mean bond strength values ranging from 15 to 60 MPa.10,11,13-15,33 One possible ex-planation for the high bond strengths observed is that the first dentin hy-bridization occurs in a stress-free en-vironment. The repeated application of dentin adhesive, after preparation and prior to cementation, might form a more uniform interface with the resin cement than that produced by the conventional cementation tech-nique.33 Hashimoto et al25 showed that multiple coatings of adhesive result in improved quality of resin-dentin bonds, due to increased bond strengths and reduced nanoleakage. However, when the dentin adhesive is applied for the second time (before cementation), both layers of dentin adhesive are subjected to polymeriza-tion shrinkage of the luting cement. If the shrinkage stress surpasses the bond strength, a gap will be formed, resulting in microleakage.3,32

In vitro studies provide important information when assessing new tech-niques to improve bonding to dental tissues. However, they have limita-tions and do not replace clinical tri-als. Clinical studies are needed prior to making clinical recommendations. The findings of the present study demonstrate the need for further in-vestigations, especially those measur-ing cyclical load and long-term effec-tiveness of IDS.

CONCLUSIONS

Immediate dentin sealing result-ed in high bond strengths for both adhesives; however, the microleak-age observed was similar to that ob-

tained with the conventional adhesive cementation technique. This study showed that cementation techniques currently in use for indirect restora-tions are not capable of producing complete sealing of the exposed den-tin, in effect, leaving a potential path-way for bacterial infiltration.

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9. Cavalcanti AN, Mitsui FH, Ambrosano GM, Mathias P, Marchi GM. Dentin bonding on different walls of a class II preparation. J Adhes Dent 2008;10:17-23.

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11.Kitasako Y, Burrow MF, Nikaido T, Tagami J. Effect of resin-coating technique on dentin tensile bond strengths over 3 years. J Esthet Restor Dent 2002;14:115-22.

12.Magne P. Immediate dentin sealing: a fundamental procedure for indirect bonded restorations. J Esthet Restor Dent 2005;17:144-54.

13.Nikaido T, Nakaoki Y, Ogata M, Foxton R, Tagami J. The resin-coating technique. Effect of a single-step bonding system on dentin bond strengths. J Adhes Dent 2003;5:293-300.

14.Nikaido T, Cho E, Nakajima M, Tashiro H, Toba S, Burrow MF, et al. Tensile bond strengths of resin cements to bovine dentin using resin coating. Am J Dent 2003;16 Spec No:41A-46A.

15.Okuda M, Nikaido T, Maruoka R, Foxton RM, Tagami J. Microtensile bond strengths to cavity floor dentin in indirect composite restorations using resin coating. J Esthet Restor Dent 2007;19:38-46.

16.Pashley DH, Pashley EL. Dentin permeabil-ity and restorative dentistry: a status report for the American Journal of Dentistry. Am J Dent 1991;4:5-9.

17.Grégoire G, Joniot S, Guignes P, Millas A. Dentin permeability: self-etching and one-bottle dentin bonding systems. J Prosthet Dent 2003;90:42-9.

18.Pashley DH, Pashley EL, Carvalho RM, Tay FR. The effects of dentin permeability on restorative dentistry. Dent Clin North Am 2002;46:211-45.

19.Pashley DH, Tay FR. Aggressiveness of con-temporary self-etching adhesives. Part II: etching effects on unground enamel. Dent Mater 2001;17:430-44.

20.Cox CF. Evaluation and treatment of bacte-rial microleakage. Am J Dent 1994;7:293-5.

21.Warfvinge J, Dahlén G, Bergenholtz G. Dental pulp response to bacterial cell wall material. J Dent Res 1985;64:1046-50.

22.Mjör IA. Clinical diagnosis of recurrent car-ies. J Am Dent Assoc 2005;136:1426-33.

23.Paul SJ, Schärer P. The dual bonding technique: a modified method to improve adhesive luting procedures. Int J Periodon-tics Restorative Dent 1997;17:536-45.

24.Guzmán-Ruiz S, Armstrong SR, Cobb DS, Vargas MA. Association between micro-tensile bond strength and leakage in the indirect resin composite/dentin adhesively bonded joint. J Dent 2001;29:145-53.

25.Koshiro K, Inoue S, Tanaka T, Koase K, Fujita M, Hashimoto M, et al. In vivo deg-radation of resin-dentin bonds produced by a self-etch vs. a total-etch adhesive system. Eur J Oral Sci 2004;112:368-75.

26.Duarte S Jr, Perdigão J, Lopes MM. Effect of dentin conditioning time on nanoleakage. Oper Dent 2006;31:500-11.

27.Perdigão J, Duarte S Jr, Lopes MM. Advanc-es in dentin adhesion. Compend Contin Educ Dent 2003;24:10-6.

28.Tay FR, King NM, Chan KM, Pashley DH. How can nanoleakage occur in self-etching adhesive systems that demineralize and infiltrate simultaneously? J Adhes Dent 2002;4:255-69.

29.Tay FR, Pashley DH, Yiu CK, Sanares AM, Wei SH. Factors contributing to the incom-patibility between simplified-step adhe-sives and chemically-cured or dual-cured composites. Part I. Single-step self-etching adhesive. J Adhes Dent 2003;5:27-40.

30.Prati C, Chersoni S, Mongiorgi R, Pashley DH. Resin-infiltrated dentin layer forma-tion of new bonding systems. Oper Dent 1998;23:185-94.

31.Tay FR, Pashley DH. Water treeing--a potential mechanism for degradation of dentin adhesives. Am J Dent 2003;16:6-12.

32.Hilton TJ, Ferracane JL. Cavity prepara-tion factors and microleakage of Class II composite restorations filled at intraoral temperatures. Am J Dent 1999;12:123-30.

33.de Andrade OS, de Goes MF, Montes MA. Marginal adaptation and microtensile bond strength of composite indirect restorations bonded to dentin treated with adhesive and low-viscosity composite. Dent Mater 2007;23:279-87.

34.Guzmán-Armstrong S, Mitchell RJ. Surface coating and leakage of dentin-bonded resin composite restorations. J Dent 2002;30:113-8.

35.Cheong C, King NM, Pashley DH, Ferrari M, Toledano M, Tay FR. Incompatibility of self-etch adhesives with chemical/dual-cured composites: two-step vs one-step systems. Oper Dent 2003;28:747-55.

36.Hashimoto M, Ito S, Tay FR, Svizero NR, Sano H, Kaga M, Pashley DH. Fluid move-ment across the resin-dentin interface during and after bonding. J Dent Res 2004;83:843-8.

37.Pashley DH. Clinical considerations of microleakage. J Endod 1990;16:70-7.

38.Dietschi D, Herzfeld D. In vitro evaluation of marginal and internal adaptation of class II resin composite restorations after thermal and occlusal stressing. Eur J Oral Sci. 1998;106:1033-42.

39.Going RE. Microleakage around dental restorations: a summarizing review. J Am Dent Assoc 1972;84:1349-57.

40.Filho AM, Vieira LC, Araújo E, Monteiro Júnior S. Effect of different ceramic surface treatments on resin microtensile bond strength. J Prosthodont 2004;13:28-35.

41.Tay FR, Pashley DH, Yoshiyama M. Two modes of nanoleakage expression in single-step adhesives. J Dent Res 2002;81:472-6.

42.Peris AR, Duarte S Jr, de Andrade MF. Eval-uation of marginal microleakage in class II cavities: effect of microhybrid, flowable, and compactable resins. Quintessence Int 2003;34:93-8.

43.Perdigão J, Geraldeli S. Bonding charac-teristics of self-etching adhesives to intact versus prepared enamel. J Esthet Restor Dent 2003;15:32-41.

Corresponding author:Dr Sillas Duarte, Jr. Department of Comprehensive Care Case School of Dental Medicine Case Western Reserve University 10900 Euclid Ave Cleveland, OH 44106-4905 Fax: 216-368-3204E-mail: [email protected]

Acknowledgments The authors thank Dr Bernard Tandler for editorial assistance. In addition, Drs Avishai Sadan and Sillas Duarte, Jr, disclose a financial interest/arrangement with 3M ESPE (hono-raria and special customer preference).

Copyright © 2009 by the Editorial Council for The Journal of Prosthetic Dentistry.



9July 2009


those obtained with the conventional cementation technique (P<.001) (Ta-ble IV). Therefore, there were signifi-cant differences between the tested cementation techniques. The interac-tion effect of cementation technique versus adhesive systems was not sig-nificant (P=84). The differences in overall bond strengths which related to the cementation techniques did not depend on the adhesive system; that is, the same cementation tech-nique differences were found for both the total-etch adhesive group and the self-etch adhesive group.

DISCUSSION

This study shows that while imme-diate dentin sealing enhanced bond strengths for both tested adhesives, it did not improve the marginal microleakage for indirect restorations. Thus, both hypotheses were rejected, since different adhesives produced sig-nificantly different scores for marginal microleakage and differences in bond strengths. Marginal sealing is impera-tive for long-term success of any in-direct restoration. In contrast, adhe-sive failure at the restoration margins can compromise the longevity of a restoration.18,39 If an adhesive failure occurs, the patient might experience postoperative sensitivity,20 recurrent caries,22 and pathologic alterations of the pulp.37 Two adhesive systems were evaluated in the present study: a total-etch (Adper Single Bond; 3M ESPE) and a self-etch (Adper Prompt L-Pop; 3M ESPE) adhesive system. There was a significant difference in the performance of the tested adhe-sive systems for microleakage and microtensile bond strength (Tables II and III).

Adper Prompt L-Pop is consid-ered a strong all-in-one self-etch ad-hesive.19 Its monomer initially has a pH as low as 1.0.26 After application of the adhesive, collagen fibers are exposed, and the hydroxyapatite is partially removed, but traces of the smear layer remain.27 The water pres-ent within dentin and in the adhesive

may not be completely removed by solvent evaporation. As a result, wa-ter becomes trapped in the micro-channels among the collagen fibrils, resulting in incomplete polymeriza-tion.28 The hybrid layer might show areas with minimal conversion inside of the polymeric matrix, with conse-quent nanoleakage.26 In addition, ad-verse chemical interaction was found when 1-step self-etch adhesives were bonded to dual-polymerizing com-posite resins.29,35 Therefore, the in-compatibility of acidic adhesive and dual-polymerizing composite resin may explain not only the high micro-leakage scores obtained for Adper Prompt L-Pop, but also the low bond strengths.

The total-etch adhesive (Adper Single Bond; 3M ESPE) showed a more favorable behavior than the self-etch adhesive (Adper Prompt L-Pop). Aging has been shown not to influence bond strengths of Adper Single Bond, regardless of the bonded walls (axial or gingival).9 However, this outcome should be interpreted with caution, since in vivo, the bond to gingival walls is significantly more subject to failure than the other prep-aration walls.7 Adper Single Bond has been reported to produce adequate dentin sealing30 and reduce dentin permeability,17 but marginal micro-leakage was not completely eliminat-ed. Some porosity within the hybrid layer created by Single Bond recently was observed.25 In addition, out-ward fluid flow is expected to occur with total-etch adhesives, even after bonding.36 The inward and outward fluid shifts create water trees, which can contribute to degradation of the resin-bonded interfaces.31

No difference was observed in mi-croleakage scores if the dentin was hy-bridized immediately after preparation or just before cementation, for both tested adhesives (Table II). However, significant differences were found for µTBS when immediate dentin sealing was used. The findings showed high-er bond strengths with IDS for both adhesive systems, particularly for the

total-etch adhesive (Table III). Im-mediate dentin sealing (IDS) is pur-ported to protect the exposed dentin after preparation.12,15,33 The appli-cation of total-etch adhesive12,23,33 or dentin adhesive associated with low-viscosity resin10,13,15 has been ad-vocated to enhance bond strengths. Most of the studies are consistent in showing that IDS produces higher bond strengths than do conventional cementation techniques, with mean bond strength values ranging from 15 to 60 MPa.10,11,13-15,33 One possible ex-planation for the high bond strengths observed is that the first dentin hy-bridization occurs in a stress-free en-vironment. The repeated application of dentin adhesive, after preparation and prior to cementation, might form a more uniform interface with the resin cement than that produced by the conventional cementation tech-nique.33 Hashimoto et al25 showed that multiple coatings of adhesive result in improved quality of resin-dentin bonds, due to increased bond strengths and reduced nanoleakage. However, when the dentin adhesive is applied for the second time (before cementation), both layers of dentin adhesive are subjected to polymeriza-tion shrinkage of the luting cement. If the shrinkage stress surpasses the bond strength, a gap will be formed, resulting in microleakage.3,32

In vitro studies provide important information when assessing new tech-niques to improve bonding to dental tissues. However, they have limita-tions and do not replace clinical tri-als. Clinical studies are needed prior to making clinical recommendations. The findings of the present study demonstrate the need for further in-vestigations, especially those measur-ing cyclical load and long-term effec-tiveness of IDS.

CONCLUSIONS

Immediate dentin sealing result-ed in high bond strengths for both adhesives; however, the microleak-age observed was similar to that ob-

tained with the conventional adhesive cementation technique. This study showed that cementation techniques currently in use for indirect restora-tions are not capable of producing complete sealing of the exposed den-tin, in effect, leaving a potential path-way for bacterial infiltration.

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1. Versluis A, Tantbirojn D, Pintado MR, De-Long R, Douglas WH. Residual shrinkage stress distributions in molars after compos-ite restoration. Dent Mater 2004;20:554-64.

2. Loguercio AD, Reis A, Schroeder M, Balduc-ci I, Versluis A, Ballester RY. Polymerization shrinkage: effects of boundary conditions and filling technique of resin composite restorations. J Dent 2004;32:459-70.

3. Uno S, Shimokobe H. Contraction stress and marginal adaptation of composite restorations in dentinal cavity. Dent Mater J 1994;13:19-24.

4. Duquia Rde C, Osinaga PW, Demarco FF, de V Habekost L Conceição EN. Cervical microleakage in MOD restorations: in vitro comparison of indirect and direct compos-ite. Oper Dent 2006;31:682-7.

5. Hasegawa EA, Boyer DB, Chan DC. Micro-leakage of indirect composite inlays. Dent Mater 1989;5:388-91.

6. Purk JH, Dusevich V, Glaros A, Eick JD. Adhesive analysis of voids in Class II composite resin restorations at the axial and gingival cavity walls restored under in vivo versus in vitro conditions. Dent Mater 2007;23:871-7.

7. Purk JH, Dusevich V, Glaros A, Spencer P, Eick JD. In vivo versus in vitro microtensile bond strength of axial versus gingival cavity preparation walls in Class II resin-based composite restorations. J Am Dent Assoc 2004;135:185-93.

8. Cavalcanti AN, Mitsui FH, Silva F, Peris AR, Bedran-Russo A, Marchi GM. Effect of cyclic loading on the bond strength of class II restorations with different composite materials. Oper Dent 2008;33:163-8.

9. Cavalcanti AN, Mitsui FH, Ambrosano GM, Mathias P, Marchi GM. Dentin bonding on different walls of a class II preparation. J Adhes Dent 2008;10:17-23.

10.Jayasooriya PR, Pereira PN, Nikaido T, Tagami J. Efficacy of a resin coating on bond strengths of resin cement to dentin. J Esthet Restor Dent 2003;15:105-13.

11.Kitasako Y, Burrow MF, Nikaido T, Tagami J. Effect of resin-coating technique on dentin tensile bond strengths over 3 years. J Esthet Restor Dent 2002;14:115-22.

12.Magne P. Immediate dentin sealing: a fundamental procedure for indirect bonded restorations. J Esthet Restor Dent 2005;17:144-54.

13.Nikaido T, Nakaoki Y, Ogata M, Foxton R, Tagami J. The resin-coating technique. Effect of a single-step bonding system on dentin bond strengths. J Adhes Dent 2003;5:293-300.

14.Nikaido T, Cho E, Nakajima M, Tashiro H, Toba S, Burrow MF, et al. Tensile bond strengths of resin cements to bovine dentin using resin coating. Am J Dent 2003;16 Spec No:41A-46A.

15.Okuda M, Nikaido T, Maruoka R, Foxton RM, Tagami J. Microtensile bond strengths to cavity floor dentin in indirect composite restorations using resin coating. J Esthet Restor Dent 2007;19:38-46.

16.Pashley DH, Pashley EL. Dentin permeabil-ity and restorative dentistry: a status report for the American Journal of Dentistry. Am J Dent 1991;4:5-9.

17.Grégoire G, Joniot S, Guignes P, Millas A. Dentin permeability: self-etching and one-bottle dentin bonding systems. J Prosthet Dent 2003;90:42-9.

18.Pashley DH, Pashley EL, Carvalho RM, Tay FR. The effects of dentin permeability on restorative dentistry. Dent Clin North Am 2002;46:211-45.

19.Pashley DH, Tay FR. Aggressiveness of con-temporary self-etching adhesives. Part II: etching effects on unground enamel. Dent Mater 2001;17:430-44.

20.Cox CF. Evaluation and treatment of bacte-rial microleakage. Am J Dent 1994;7:293-5.

21.Warfvinge J, Dahlén G, Bergenholtz G. Dental pulp response to bacterial cell wall material. J Dent Res 1985;64:1046-50.

22.Mjör IA. Clinical diagnosis of recurrent car-ies. J Am Dent Assoc 2005;136:1426-33.

23.Paul SJ, Schärer P. The dual bonding technique: a modified method to improve adhesive luting procedures. Int J Periodon-tics Restorative Dent 1997;17:536-45.

24.Guzmán-Ruiz S, Armstrong SR, Cobb DS, Vargas MA. Association between micro-tensile bond strength and leakage in the indirect resin composite/dentin adhesively bonded joint. J Dent 2001;29:145-53.

25.Koshiro K, Inoue S, Tanaka T, Koase K, Fujita M, Hashimoto M, et al. In vivo deg-radation of resin-dentin bonds produced by a self-etch vs. a total-etch adhesive system. Eur J Oral Sci 2004;112:368-75.

26.Duarte S Jr, Perdigão J, Lopes MM. Effect of dentin conditioning time on nanoleakage. Oper Dent 2006;31:500-11.

27.Perdigão J, Duarte S Jr, Lopes MM. Advanc-es in dentin adhesion. Compend Contin Educ Dent 2003;24:10-6.

28.Tay FR, King NM, Chan KM, Pashley DH. How can nanoleakage occur in self-etching adhesive systems that demineralize and infiltrate simultaneously? J Adhes Dent 2002;4:255-69.

29.Tay FR, Pashley DH, Yiu CK, Sanares AM, Wei SH. Factors contributing to the incom-patibility between simplified-step adhe-sives and chemically-cured or dual-cured composites. Part I. Single-step self-etching adhesive. J Adhes Dent 2003;5:27-40.

30.Prati C, Chersoni S, Mongiorgi R, Pashley DH. Resin-infiltrated dentin layer forma-tion of new bonding systems. Oper Dent 1998;23:185-94.

31.Tay FR, Pashley DH. Water treeing--a potential mechanism for degradation of dentin adhesives. Am J Dent 2003;16:6-12.

32.Hilton TJ, Ferracane JL. Cavity prepara-tion factors and microleakage of Class II composite restorations filled at intraoral temperatures. Am J Dent 1999;12:123-30.

33.de Andrade OS, de Goes MF, Montes MA. Marginal adaptation and microtensile bond strength of composite indirect restorations bonded to dentin treated with adhesive and low-viscosity composite. Dent Mater 2007;23:279-87.

34.Guzmán-Armstrong S, Mitchell RJ. Surface coating and leakage of dentin-bonded resin composite restorations. J Dent 2002;30:113-8.

35.Cheong C, King NM, Pashley DH, Ferrari M, Toledano M, Tay FR. Incompatibility of self-etch adhesives with chemical/dual-cured composites: two-step vs one-step systems. Oper Dent 2003;28:747-55.

36.Hashimoto M, Ito S, Tay FR, Svizero NR, Sano H, Kaga M, Pashley DH. Fluid move-ment across the resin-dentin interface during and after bonding. J Dent Res 2004;83:843-8.

37.Pashley DH. Clinical considerations of microleakage. J Endod 1990;16:70-7.

38.Dietschi D, Herzfeld D. In vitro evaluation of marginal and internal adaptation of class II resin composite restorations after thermal and occlusal stressing. Eur J Oral Sci. 1998;106:1033-42.

39.Going RE. Microleakage around dental restorations: a summarizing review. J Am Dent Assoc 1972;84:1349-57.

40.Filho AM, Vieira LC, Araújo E, Monteiro Júnior S. Effect of different ceramic surface treatments on resin microtensile bond strength. J Prosthodont 2004;13:28-35.

41.Tay FR, Pashley DH, Yoshiyama M. Two modes of nanoleakage expression in single-step adhesives. J Dent Res 2002;81:472-6.

42.Peris AR, Duarte S Jr, de Andrade MF. Eval-uation of marginal microleakage in class II cavities: effect of microhybrid, flowable, and compactable resins. Quintessence Int 2003;34:93-8.

43.Perdigão J, Geraldeli S. Bonding charac-teristics of self-etching adhesives to intact versus prepared enamel. J Esthet Restor Dent 2003;15:32-41.

Corresponding author:Dr Sillas Duarte, Jr. Department of Comprehensive Care Case School of Dental Medicine Case Western Reserve University 10900 Euclid Ave Cleveland, OH 44106-4905 Fax: 216-368-3204E-mail: [email protected]

Acknowledgments The authors thank Dr Bernard Tandler for editorial assistance. In addition, Drs Avishai Sadan and Sillas Duarte, Jr, disclose a financial interest/arrangement with 3M ESPE (hono-raria and special customer preference).

Copyright © 2009 by the Editorial Council for The Journal of Prosthetic Dentistry.

Documents

The effect of immediate dentin sealing on the marginal adaptation and bond strengths of total-etch and self-etch adhesives