Search PubMed⌕ Search

Biomedical subjects

Jorge Perdigão

Publications and source records attributed to Jorge Perdigão.

At least 19 recordsLinked to original sources
PubMed2006

The effect of silane on the bond strengths of fiber posts.

OBJECTIVES: Esthetic posts have been developed to maximize the foundation of esthetic restorations. The purpose of this study was to evaluate the effect of silane on the bond strength of three fiber-reinforced resin posts (fiber posts). METHODS: Fifty-four extracted human maxillary central incisors and canines were endodontically treated. D.T. Light Post (DT, Bisco), FRC Postec (FR, Ivoclar Vivadent), and ParaPost Fiber White (PP, Coltène/Whaledent) were inserted using the resin adhesive system provided by the respective manufacturer. For half of the specimens in each group, the fiber posts were treated with a silane solution (Monobond S, Ivoclar Vivadent). A push-out test was performed on three different sections of each root to measure bond strengths. Data were analyzed with ANOVA and Bonferroni's post hoc test at P<0.05. RESULTS: The use of silane did not result in any statistically significant difference at any level of the root. Silane did not result in any significant different bond strengths (MPa) for each of the posts. When the data were pooled, the use of silane did not result in statistically significant different bond strengths at P>0.403: No silane=12.7+/-8.4; Silane=14.1+/-7.0. The coronal third of the root (17.5+/-6.7) resulted in statistically greater bond strengths than the medium third (12.9+/-6.8) and than the apical third (9.8+/-7.3) at P<0.002 and P<0.0001, respectively. The medium third and the apical third resulted in no statistically significant different bond strengths from each other at P>0.07. The type of post did not result in statistically significant different bond strengths at P>0.417: DT=14.7+/-6.8 MPa; FR=13.3+/-6.6 MPa; PP=12.2+/-6.6 MPa. SIGNIFICANCE: The use of a silane coupling agent did not increase the push-out bond strengths of the three fiber posts used in this study. All posts bonded to root dentin at the same magnitude. Bonding is more predictable at the most coronal level of the root.

Bismuth↗
PubMed2006

Influence of conditioning time on enamel adhesion.

OBJECTIVE: The aim of this study was to calculate enamel bond strengths of 4 self-etch adhesives in function of conditioning time. METHODS AND MATERIALS: Sixty proximal surfaces of 30 extracted human molars were roughened and assigned to 4 self-etch adhesives: AdheSE (Ivoclar Vivadent), Adper Prompt L-Pop (3M Espe), Clearfil SE Bond (Kuraray America), and Tyrian SPE/One-Step Plus (Bisco). Prime & Bond NT (Dentsply) was used as the total-etch control. For 30 surfaces, the adhesives were applied per the manufacturers' directions. For the remaining 30, enamel was conditioned for twice the time recommended by the manufacturer. Buildups were constructed with Filtek Z250 (3M ESPE). Bonded specimens were sectioned in sticks and tested to tensile failure. Data were analyzed with 2-way ANOVA and Duncan's test at P < .05. The pH of the self-etch solutions and the phosphoric acid gel was measured with a pH meter. A correlation coefficient was computed to measure the linear association between pH and bond strengths. RESULTS: Tyrian SPE and Prime & Bond NT, the adhesives whose acidic conditioners yielded the lowest pH, ranked in the highest subset regardless of application time. AdheSE and Clearfil SE Bond, which had the highest pH, were the only adhesives for which double application time resulted in statistically higher bond strengths than the recommended time. When means were pooled for application time, Tyrian SPE and Prime & Bond NT resulted in bond strengths that were significantly higher than those of the remaining adhesives. AdheSE resulted in statistically lower bond strengths than any other adhesive. A significant correlation was found between pH and mean bond strengths. CONCLUSION: Doubling the enamel conditioning time might increase bond strengths for specific self-etch adhesives.

Acid Etching, Dental↗
PubMed2006

Dentin bond strengths of simplified adhesives: effect of dentin depth.

The objective of this study was to compare the shear bond strength of 3 simplified adhesive systems applied on shallow vs deep dentin. For superficial dentin, 30 human molars were sectioned with a diamond saw to expose dentin immediately below the dentoenamel junction. For deep dentin, 30 molars were sectioned 3 mm below the dentoenamel junction. The teeth were mounted, polished to 600-grit, and randomly assigned to 3 groups (n=10): Single Bonda and OptiBond Solo, total-etch adhesives, and Clearfil Liner Bond 2V, a self-etching primer adhesive. Adhesives were applied, the restorative material Filtek Z250 inserted in a No. 5 gelatin capsule, and light-cured. After 24 hours in water at 37 degrees C, shear bond strength was measured with an Instron at 5 mm/min. The data were analyzed with 2-way ANOVA and Duncan's post-hoc test. The results showed the following shear bond strengths (mean +/- SD in MPa): Single Bond/superficial dentin = 22.1 +/- 2.8; Single Bond/deep dentin = 14.2 +/- 7.0; OptiBond Solo/superficial dentin = 18.9 +/- 4.1; OptiBond Solo/deep dentin = 18.4 +/- 4.8; Clearfil Liner Bond 2V/superficial dentin = 21.0 +/- 7.4; Clearfil Liner Bond 2V/deep dentin = 17.6 +/- 5.9. There were no significant differences between mean shear bond strength for the factor "adhesive system" (P>.822). The Duncan's test showed that Single Bond resulted in higher shear bond strength on superficial dentin than on deep dentin. The mean shear bond strength for Clearfil Liner Bond 2V and OptiBond Solo were not influenced by dentin depth. When data were pooled for dentin depth, deep dentin resulted in statistically lower bond strengths than superficial dentin (P<.01). The influence of dentin depth on shear bond strength depends on the specific composition of the dentin adhesive.

Analysis of Variance↗
PubMed2005

Clinical performance of a self-etching adhesive at 18 months.

PURPOSE: To test the null hypothesis that beveling and/or etching enamel would not affect the 18-month clinical performance of the self-etching adhesive Clearfil SE Bond (CSEB) in noncarious cervical lesions (NCCL). METHODS: With Institutional Review Board approval, 34 patients were enrolled in this study. A total of 120 NCCL was selected and assigned to four groups: (1) CSEB was applied without any cavity preparation; (2) CSEB was applied after beveling enamel; (3) CSEB was applied after etching enamel for 15 seconds with 35% phosphoric acid; (4) CSEB was applied after beveling and etching enamel. A microfilled composite resin was used for all restorations. RESULTS: At 6 months after initial placement, 120 restorations (a 100% recall rate) were evaluated. At 18 months, 87 restorations (a 72.5% recall rate) were available for evaluation. A survival rate of 100% was measured for all groups at both 6 and 18 months. Sensitivity to air decreased significantly only for Group 3 (no bevel+acid etch) from baseline to 18 months without statistical changes from 6 months to 18 months. None of the other parameters resulted in significant differences for any of the four groups. However, when data were pooled, both the overall marginal discoloration and the overall marginal adaptation were significantly worse at 18 months than at baseline, while sensitivity to air decreased significantly from baseline to 18 months. The 18-month survival rate of the self-etching adhesive Clearfil SE Bond was not improved by enamel bevel or by enamel etching. Both overall marginal adaptation and overall marginal discoloration were worse at 18 months than at baseline. .

Acid Etching, Dental↗
PubMed2005

Eighteen-month clinical evaluation of two dentin adhesives applied on dry vs moist dentin.

PURPOSE: To evaluate the influence of substrate moisture on the clinical behavior of two dentin adhesives after 18 months. The null hypothesis tested was that drying dentin with air upon rinsing off the acid would not influence the clinical performance of two dentin adhesives as compared to leaving the preparation visibly moist. MATERIALS AND METHODS: Thirty-five patients were enrolled in this study. One hundred twenty-eight restorations divided into 4 groups were inserted and evaluated at baseline: (1) NT/Moist - Prime & Bond NT, an acetone-based adhesive, applied on moist dentin; (2) NT/Dried - Prime & Bond NT applied on dentin dried with air for 3 to 4 s; (3) SB/Moist - Single Bond, an ethanol- and water-based adhesive, applied on moist dentin; (4) SB/Dried - Single Bond applied on dentin dried with air for 3 to 4 s. A microfilled composite resin was used for all restorations. Patients were recalled at 6 and 18 months. RESULTS: At 18 months after initial placement, 110 restorations (86% recall rate) were re-evaluated. Retention rates at 18 months were 92% for NT/Moist, 93% for NT/Dried, 100% for SB/Moist, and 89% for SB/Dried. No statistically significant differences were found among groups for retention rate. Both NT/Moist and SB/Moist resulted in a significant decrease in sensitivity to air from baseline to 18 months. When data were pooled for the variable "substrate moisture", SB resulted in an overall retention rate of 95%, while NT resulted in a retention rate of 92% (statistically similar). The marginal adaptation with SB was significantly worse at 18 months than at baseline. CONCLUSION: The moisture level of the dentin substrate in noncarious cervical lesions does not influence retention of composite restorations, but moist conditions caused less sensitivity to air. When applied as per manufacturers' instructions (moist dentin), both adhesives resulted in Class V retention rates exceeding the ADA 18-month full acceptance guidelines.

Acrylic Resins↗
PubMed2004

Contemporary trends and techniques in tooth whitening: a review.

UNLABELLED: The popularity of tooth whitening has increased with the advent of patient-applied, peroxide-based whitening agents, as well as increased media influence. Peroxides are considered effective and safe when used under professional supervision. Whitening methods include those prescribed by a dental professional for the patient's at-home use, those applied by the dental professional in the office, a combination of both, or methods available over the counter (OTC). This article reviews the effect of contemporary whitening agents and illustrates the clinical application of three methods prescribed by dental professionals. LEARNING OBJECTIVES: This article presents the use of three different types of whitening agents for improved aesthetics. Upon reading this article, the reader should be able to: Distinguish the difference between professionally administered in-office and at-home tooth-whitening results. Identify the effects of whitening agents on dental tissues.

Humans↗
PubMed2004

Influence of acid etching and enamel beveling on the 6-month clinical performance of a self-etch dentin adhesive.

This study tested the hypothesis that beveling and/or etching enamel does not affect the 6-month clinical performance of the self-etch adhesive Clearfil SE Bond in class V noncarious lesions. With Institutional Review Board approval, 34 patients were enrolled in this study. A total of 120 noncarious cervical lesions were selected and assigned to 4 groups: (1) Clearfil SE Bond was applied without any cavity preparation; (2) After the enamel was beveled, Clearfil SE Bond was applied; (3) After the enamel was etched for 15 seconds with 35% phosphoric acid, Clearfil SE Bond was applied; (4) After the enamel was beveled and etched with 35% phosphoric acid for 15 seconds, Clearfil SE Bond was applied. A microfilled composite resin was used for all restorations. Six months after initial placement, 120 restorations (a 100% recall rate) were re-evaluated. Retention rates at 6 months were 100% for all groups. Sensitivity to air improved from baseline to 6 months, but the overall difference was not statistically significant. The 6-month retention rate of the self etch dentin adhesive system Clearfil SE Bond was not improved by enamel beveling or by enamel etching. For the self-etch material Clearfil SE Bond, instrumentation or etching of enamel may not be critical for its clinical performance at 6 months.

Acid Etching, Dental↗
PubMed2004

Push-out bond strengths of tooth-colored posts bonded with different adhesive systems.

PURPOSE: To evaluate the effect of luting systems and root region on the push-out bond strengths of a glass fiber-reinforced post and a zirconia post. METHODS: Thirty-two extracted human anterior teeth (central incisors and canines) were endodontically treated with lateral condensation of gutta percha and AH26 sealer. Teeth were randomly assigned to eight groups (n = 4 per group). Two post systems from the same manufacturer (Cosmopost, a zirconia post; or FRC Postec, a glass fiber-reinforced post) were placed with a luting system (bonding agent and resin luting agent). C-Post was cemented with One-Step and Post Cement Hi-X was used as the light-polymerized adhesive control. ParaPost Fiber White cemented with ParaPost Adhesive and ParaPost Resin Cement was used as an auto-polymerized adhesive control. The roots were sectioned in equal thirds (apical, middle and cervical). A push-out test was performed in each section to measure regional bond strengths in MPa. Means were analyzed with two-way ANOVA and Duncan's post-hoc test (alpha = 0.05). RESULTS: The fiber posts ranked in the highest statistical subset regardless of the luting system: ParaPost Fiber White (self-cure control), FRC Postec bonded with Excite DSC/Variolink II, FRC Postec bonded with Syntac/Variolink II, FRC Postec bonded with Excite DSC/Experimental Self Cure Cement, and C-Post bonded with One Step/Hi-X. The zirconia post Cosmopost ranked in the lowest subsets regardless of the adhesive system used at P < 0.05. Means for the medium region of the root (5.0 +/- 0.8 MPa) were not statistically different from those obtained either in the cervical or in the apical region. Means for the cervical root region (6.2 +/- 0.9 MPa) were statistically higher than those of the apical region (4.5 +/- 1.1 MPa) at P < 0.001.

Composite Resins↗
PubMed2003

Immunocytochemical identification of type I collagen in acid-etched dentin.

The hypothesis tested in this study is that the application of phosphoric acid prevents collagen fibrils (CF) from maintaining their structural morphology, as assessed by their immunochemical antigenicity. Dentin was conditioned with EDTA and with 35% H3PO4 for 15, 30, and 60 s. For a control there was no treatment. A pre-embedding immunohistochemical procedure was evaluated under high-resolution SEM and a postembedding immunolocalization technique was performed on ultrathin sections at TEM level. Conditioning with EDTA resulted in a weaker labeling signal than for dentin conditioned with H3PO4. The most intense labeling was observed after dentin had been etched with H3PO4 for 15 s. The least intensive labeling was evident when the acid was applied for 30 s or for 60 s. A very weak signal was detected on the untreated dentin surface. These results provide evidence that a 15-s application of 35% H3PO4 causes mineral dissolution of the crystals enveloping the superficial CF without damaging the ultrastructure of the CF while longer applications of 35% H3PO4 cause alterations in the CF that decrease their antigenicity.

Acids↗
PubMed2003

Bonding characteristics of self-etching adhesives to intact versus prepared enamel.

PURPOSE: This study tested the null hypothesis that the preparation of the enamel surface would not affect the enamel microtensile bond strengths of self-etching adhesive materials. MATERIALS AND METHODS: Ten bovine incisors were trimmed with a diamond saw to obtain a squared enamel surface with an area of 8 x 8 mm. The specimens were randomly assigned to five adhesives: (1) ABF (Kuraray), an experimental two-bottle self-etching adhesive; (2) Clearfil SE Bond (Kuraray), a two-bottle self-etching adhesive; (3) One-Up Bond F (Tokuyama), an all-in-one adhesive; (4) Prompt L-Pop (3M ESPE), an all-in-one adhesive; and (5) Single Bond (3M ESPE), a two-bottle total-etch adhesive used as positive control. For each specimen, one half was roughened with a diamond bur for 5 seconds under water spray, whereas the other half was left unprepared. The adhesives were applied as per manufacturers' directions. A universal hybrid composite resin (Filtek Z250, 3M ESPE) was inserted in three layers of 1.5 mm each and light-cured. Specimens were sectioned in X and Y directions to obtain bonded sticks with a cross-sectional area of 0.8 +/- 0.2 mm2. Sticks were tested in tension in an Instron at a cross-speed of 1 mm per minute. Statistical analysis was carried out with two-way analysis of variance and Duncan's test at p < .05. Ten extra specimens were processed for observation under a field-emission scanning electron microscope. RESULTS: Single Bond, the total-etch adhesive, resulted in statistically higher microtensile bond strength than any of the other adhesives regardless of the enamel preparation (unprepared = 31.5 MPa; prepared = 34.9 MPa, not statistically different at p < .05). All the self-etching adhesives resulted in higher microtensile bond strength when enamel was roughened than when enamel was left unprepared. However, for ABF and for Clearfil SE Bond this difference was not statistically significant at p > .05. When applied to ground enamel, mean bond strengths of Prompt L-Pop were not statistically different from those of Clearfil SE Bond and ABF. One-Up Bond F did not bond to unprepared enamel. Commercial self-etching adhesives performed better on prepared enamel than on unprepared enamel. The field-emission scanning electron microscope revealed a deep interprismatic etching pattern for the total-etch adhesive, whereas the self-etching systems resulted in an etching pattern ranging from absent to moderate.

Acid Etching, Dental↗
PubMed2003

Total-etch versus self-etch adhesive: effect on postoperative sensitivity.

BACKGROUND: Self-etching adhesives are believed to prevent postoperative sensitivity when used under posterior resin-based composite restorations. The authors tested a twofold hypothesis: a self-etch, or SE, adhesive would result in less postoperative sensitivity than a total-etch, or TE, adhesive; an SE adhesive would result in poorer enamel marginal integrity than a TE adhesive. METHODS: Patients were selected on the basis of requiring Class I and II restorations in molars and premolars. The authors placed 30 restorations with the SE material (Clearfil SE Bond, Kuraray America, New York) and 36 restorations with Prime & Bond NT (Dentsply Caulk, Milford, Del.), which uses 34 percent phosphoric acid to etch enamel and dentin simultaneously. Preparations were of standard design, with all margins in enamel without beveling. Upon rubber dam isolation, the authors conditioned the enamel and dentin walls with the self-etching primer (for Clearfil SE Bond) or etched with the proprietary 34 percent phosphoric acid (for Prime & Bond NT), followed by application of the corresponding dentin adhesive. Teeth were restored with the proprietary hybrid resin-based composite indicated for posterior restorations: Clearfil AP-X for Clearfil SE Bond or Esthet-X Micro Matrix Restorative for Prime & Bond NT. The restored teeth were evaluated preoperatively and at two weeks, eight weeks and six months postoperatively for sensitivity to cold (ice), air and masticatory forces, as well as for marginal discoloration. RESULTS: Analysis of variance revealed no statistically significant differences in postoperative sensitivity between the SE and TE materials at any recall time. Marginal discoloration was rated as "absent" for all restorations at six months. Only one tooth displayed sensitivity to occlusal forces at six months. CONCLUSION: The SE adhesive did not differ from the TE adhesive in regard to sensitivity and marginal discoloration. CLINICAL IMPLICATIONS: Postoperative sensitivity may depend on the restorative technique rather than on the type of dentin adhesive used.

Acid Etching, Dental↗
PubMed2003

Morphological study of resin-dentin bonding with TEM and in-lens FESEM.

PURPOSE: To evaluate the morphological characteristics of the dentin-resin interface using high-magnification electron microscopy and correlate the TEM findings of resin-dentin interfaces with the corresponding in-lens Field Emission SEM (FEISEM) observation. METHODS: Twelve 800 microm-thick dentin disks were obtained from middle dentin and assigned to four groups: (1) a self-etching adhesive material, Clearfil SE Bond; (2) a solvent-free total-etch simplified adhesive, One Coat Bond; (3) an acetone-based total-etch simplified adhesive, Prime&Bond NT; (4) an acetone-based total-etch simplified adhesive, Prime&Bond NT, upon a short dentin deproteinization with 10% NaOCl gel (AD Gel) for 15 seconds. Disks were restored with a 1 mm thick layer of a low-viscosity composite. Four sticks with a cross section of 1 mm2 were taken from each restored dentin disk, decalcified in buffered 10% EDTA, fixed, and stained with lead citrate followed by uranyl acetate, or kept in water. The sticks were sectioned in 85 nm-thick slices, and mounted on Ni grids. After TEM observation, the same grids were coated with a 1.5 nm Pt-C film and observed under the FEISEM. RESULTS: The TEM analysis revealed an intimate adaptation of all adhesive systems to dentin, with penetrating resin tags observed in transverse sections. The FEISEM revealed novel morphological features usually observed in the resin-dentin interface with distinctive arrangement for each of the adhesive systems. FEISEM and TEM appear as mutually complementary tools for the fine observation of the ultra-structure and the spatial relationship between the resin components and the collagen fibers of the hybrid layer.

Collagen↗
PubMed2003

Bond strengths of tooth-colored posts, effect of sealer, dentin adhesive, and root region.

PURPOSE: To evaluate the effect of sealer, dentin bonding agent, and root region on the push-out bond strengths of three tooth colored posts. METHODS: 24 extracted human single rooted maxillary central incisors and canines were endodontically-treated using gutta percha and Roth's 801 or AH26 sealer. Posts (Cosmopost, Fibrekor, or Parapost Fiber White) were placed using one of two adhesive systems (Parapost Cement Conditioner with Parapost Cement, or One-Step with Hi-X Post self-cure resin cement). The push-out test was performed on different sections of the root to measure bond strengths. RESULTS: Cosmopost showed significantly lower mean bond strengths than either Fibrekor or Parapost. Bond strengths of the posts in the crown section were significantly higher than those in any of the three root areas measured. Neither the eugenol-containing sealer nor the bonding agent type had any effect on bond strength. Post type and root region significantly affected bond strength while sealer type or bonding agent had no effect on bond strength.

Analysis of Variance↗
PubMed2003

Ultra-morphology of self-etching adhesives on ground enamel: a high resolution SEM study.

PURPOSE: To evaluate the effect of different commercial self-etching agents on enamel morphology using high-resolution in-lens scanning electron microscopy (FEISEM). METHODS: The bonding systems selected for the study were: Prime & Bond NT (no-etch technique), Prime & Bond 2.1 (no-etch technique), NRC/Prime and Bond NT, Syntac Single Component, Prompt L-Pop, F2000, and Clearfil SE Bond. The positive control group was prepared with Single Bond upon etching enamel with the proprietary 35% phosphoric acid gel. 24 extracted human molars were equally and randomly assigned to the experimental and control groups. All bonding materials were applied on enamel following the manufacturers' instructions. A thin layer of composite was applied on the polymerized adhesive agent, after which the enamel was dissolved to obtain replicas that were observed under a FEISEM. RESULTS: Observations revealed different morphological features brought about by the adhesive systems. A relationship between the morphological appearance and the pH of the adhesive solutions was found. Three different groups of self etching were identified: Group 1 showed no or little evidence of modifications on the enamel surface (Prime & Bond NT and Prime & Bond 2.1, no-etch technique), Group 2 revealed major aggressive properties that were able to disclose the prism morphology (Syntac Single Component, F2000, Clearfil SE Bond), and Group 3 (NRC/Prime & Bond NT and Prompt L-Pop) revealed morphological features similar to those obtained with Single Bond after etching with phosphoric acid (control group).

Acetone↗
PubMed2003

Advances in dentin adhesion.

While bonding to enamel has been a dependable technique, bonding to dentin is still an overwhelming task--dentin is a naturally soaked organic tissue. The enamel bonding agents of the 1960s and 1970s progressively evolved into complex multibottle or universal adhesives in the early 1990s. These multibottle systems were formulated to bond to enamel, dentin, composite, amalgam, porcelain, and nonprecious metal. More recently, simplified dentin adhesives were introduced following one of two adhesion strategies: total-etch adhesives that include an acid gel to remove the smear layer and dissolve hydroxyapatite (generally 30% to 40% phosphoric acid for 15 to 30 seconds); and self-etching primers that treat the dentin and enamel with a non-rinsing solution of acidic monomers in water without removing the smear layer. Recent attempts to simplify the bonding procedure have led to the introduction of adhesives that do not use a separate acid-etch step and, therefore, do not etch enamel to the same depth as phosphoric acid-based dental adhesives.

Acid Etching, Dental↗
PubMed2002

Dentin bonding as a function of dentin structure.

The traditional principles of operative dentistry have been challenged since Dr. Buonocore introduced the aid-etch technique in 1955. In spite of the numerous changes in clinical protocols and adhesive techniques, adhesion to dentin remains difficult. The importance of micromechanical bonding to dentin has been recognized over the last decade. Researchers now believe that dentin adhesion relies primarily on the penetration of adhesive monomers into the filigree of collagen fibers left exposed by acid etching. Two main strategies are currently in use for bonding to enamel and dentin: the self-etch technique and the total-etch technique. The efficiency of either bonding strategy depends very much on the dentin substrate used for bonding. Laboratory tests use ideal dentin from extracted teeth, which does not reflect the clinical reality. Clinical studies are the ultimate test for any dental adhesive material.

Clinical Trials as Topic↗
PubMed2002

The use of flowable composites as filled adhesives.

OBJECTIVE: The effect of filled adhesives on bonding resin composites to dentin has not been fully understood. Due to their filler content, filled adhesives may act as stress breakers. The aim of this in vitro study was to evaluate the use of flowable composites of different viscosities on bonding to enamel and dentin without the use of an intermediate bonding resin. MATERIALS AND METHODS: Enamel and dentin bond strengths of OptiBond FL, Syntac Classic, and EBS Multi combined either with their proprietary bonding agent or a flowable resin composite (Ultraseal XT Plus or Revolution) were measured. The tests were carried out with a microtensile device at a crosshead speed of 1mm/min after 24h of storage at 37 degrees C in water. Mean bond strengths were analyzed using the Wilcoxon test and multiple comparisons according to the Mann-Whitney U-test. The micro-morphology of corresponding resin-dentin interfaces of the same teeth were analyzed using SEM and TEM. RESULTS: The control groups with adhesive systems used as per manufacturers' protocol showed bond strengths of 38.9-41.1 MPa to enamel and 28.8-33.4 MPa to dentin. With respect to bond strength to etched enamel, only Ultraseal XT Plus as bonding resin reached the level of the control groups. When used as bonding agents on dentin, both flowable composites produced lower microtensile bond strengths to etched and primed dentin than did the control groups. Micro-morphological analysis using SEM and TEM resulted in hybrid layer formation for both control and experimental groups. However, many areas of the resin-dentin interface showed insufficient penetration of the flowable composites at the top of the hybrid layer as well as numerous tubules obstructed by filler particles. CONCLUSIONS: The flowable composites tested in this study should not be used to replace bonding agents. Flowable composites of thinner viscosity, such as Ultraseal XT Plus, may bond to enamel adequately without the requirement of an intermediate bonding resin.

Acid Etching, Dental↗