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In comparison to enamel, bonding to normal dentin is a greater challenge because of its organic constituents, fluid-filled tubules, and variations in intrinsic composition. Bonding to sclerotic dentin is even more difficult. To evaluate the shear bond strengths of four adhesive systems to dentin substrates with different levels of mineralization, 120 extracted human teeth were randomly assigned to three groups (n = 40). After mid-coronal dentin was exposed, groups of specimens were artificially hypermineralized by immersion in a remineralizing solution, demineralized by means of an acetic acid demineralizing solution, or stored in distilled water to model sclerotic, carious, and normal dentin, respectively. Resin composite was bonded to dentin by use of commercial adhesive systems. After the specimens were thermocycled, shear bond strengths were determined in an Instron universal testing machine. Dentin substrates and resin/dentin interfaces were examined by SEM. For each adhesive system, the mean shear bond strength to normal dentin was significantly higher than that to either of the other substrates. Shear bond strengths to hypermineralized dentin were significantly higher than those to demineralized dentin with all adhesives except Prisma Universal Bond 3.

This study evaluated the effects of chemical biocides used to control dental unit waterline biofilm on the bond strength of resin to enamel. Sixty bovine teeth were randomly assigned to six treatment groups. One-way ANOVA revealed a significant difference in means (p0.001) and Tukey's multiple range test indicated that three of the experimental groups had significantly lower mean shear bond strengths than the control (p0.05). This finding suggests that dental unit waterline biocides may adversely affect adhesion of resin to enamel.

Currently, two approaches are available for bonding resin-based materials to dentin--total-etch and self-etch. The total-etch approach, using either a three-step or a two-step method, has been available for several years. Clinical studies have demonstrated excellent success rates for total-etch adhesives, but many clinicians report problems with postoperative sensitivity. The self-etch approach, which is relatively new to the US market, reduces the incidence of postoperative sensitivity. However, the long-term clinical performance of self-etch materials--particularly those that use a single solution to etch, prime, and bond--is not yet proven. This article provides an overview of the current options for bonding resin to dentin.

To evaluate the shear bond strengths of "one-bottle" adhesives to dentin when used with self-cured composite.100 bovine teeth were ground to expose superficial dentin, which was polished to 600-grit. The dentin was etched for 15 s with 35% phosphoric acid, rinsed, and blotted with tissue paper. The surface remained visibly moist for all specimens. The following adhesives were applied to the etched dentin according to manufacturers' directions: Scotchbond Multi-Purpose (in its visible light-cured [VLC] and self-cure modes) as a control, One-Step (VLC only), OptiBond Solo Plus (VLC only), PrimeBond NT (VLC) and PrimeBond NT Dual-Cure. For each adhesive, specimens were bonded with a self-cure composite, while 10 were bonded with a VLC composite as a control. After 24 hrs water storage, shear bond strengths were determined using an Instron universal testing machine. Data were analyzed using two-way ANOVA, Tukey's test, and Student's t-tests.Using the light-cured composite, mean bond strengths ranged from 11.0 MPa for light-cured PrimeBond NT to 26.3 MPa for OptiBond Solo Plus. Using the self-cure composite, mean bond strengths ranged from 0.0 for light-cured PrimeBond NT to 21.4 MPa for One-Step. Two adhesives, light-cured PrimeBond NT and OptiBond Solo Plus, had significantly lower bond strengths when used with the self-cure composite.Some "one-bottle" dentin adhesives may not provide acceptable bonding to tooth structure when they are used with self-cure composites.

To evaluate the effect of different phosphoric acid concentrations (10% and 37%) on the microtensile bond strengths (microTBS) of three dentin adhesive systems with different solvents (ethanol, acetone, or none).Eighteen third molars divided into six groups were ground flat to expose superficial dentin, which was polished to 600-grit. The bonding procedure was initiated using either of two phosphoric acid gels (10% and 37%). Three adhesive systems - Single Bond (SB), PrimeBond NT (NT), and One Coat Bond (OC) - with different solvents (ethanol, acetone, or none, respectively) were used. After adhesive application, a cylinder of composite resin was built up. After 24 h water storage, each tooth was serially sectioned into thin rectangular sections (or "sticks") parallel to the long axis and with a mean cross-sectional area of 0.4 mm2. microTBS were determined using an Instron universal testing machine. Data were analyzed using two-way ANOVA and Duncan's test.Mean bond strengths ranged from 66.1 MPa for 10%/ H3PO4 and SB to 43.8 MPa for 37% H3PO4 and OC. SB and OC tended to have slightly higher bond strengths when 10% H3PO4 was used. NT with 37% H3PO4 had a significantly higher microTBS (54.6 MPa) than NT with 10% H3PO4 (44.4 MPa).Etching dentin with 37% H3PO4 resulted in a significantly higher mean microTBS for the acetone-based adhesive NT. For both the ethanol- and water-based adhesive (SB) and the solvent-free adhesive (OC), acid concentration did not significantly affect bond strength.

To compare the in vitro shear bond strengths (SBS) of five simplified dentin adhesives. The tested hypothesis was that the recently introduced simplified adhesive systems would have similar or higher SBS than an existing simplified acetone-based adhesive used as a control.100 flat bonding sites were polished to 600-grit on the labial surface of bovine incisors mounted in acrylic resin. 50 teeth were ground to expose enamel, while the remaining 50 specimens were prepared to expose middle dentin. The specimens were randomly divided into five equal groups to be treated with simplified dentin adhesives: Dentastic Uno, EasyBond, Gluma One Bond, One Coat Bond, and One-Step (control). A composite post was bonded to each treatment area. After thermo-cycling, enamel and dentin shear bond strengths were determined using an Instron testing machine and the data were submitted to statistical analyses.Mean enamel bond strengths ranged from 14.6-28.4 MPa. One Coat Bond had the highest mean enamel SBS, but it was not significantly higher than those of Gluma One Bond and Dentastic Uno. EasyBond and One-Step had statistically similar mean enamel SBS and these were significantly lower than the mean enamel SBS of the other three adhesives. For dentin, mean SBS ranged from 14.8-21.7 MPa. Dentastic Uno had the highest mean dentin SBS, but it was not significantly greater than those of One Coat Bond and Gluma One Bond. Although One Step had the lowest mean dentin SBS, it was not significantly different from those of either EasyBond or Gluma One Bond.

To compare the in vitro bond strengths of two acetone-based one-bottle dentin adhesives applied to four surface moisture conditions. The tested hypothesis was that wetting a dried dentin surface with an aqueous HEMA solution would result in bond strengths similar or higher than those obtained by leaving the surface moist as per manufacturers' instructions.Eighty flat dentin bonding sites were polished to 600-grit on middle dentin of the labial surface of bovine incisors mounted in acrylic resin. The specimens were equally and randomly divided between two acetone-based dentin adhesives (One-Step and PrimeBond 2.1) and four different levels of surface moisture (moist dentin, dentin dried for 1 s, dentin dried for 5 s, and dentin dried for 5 s followed by re-wetting with Aqua-Prep, an aqueous HEMA solution). A composite post was then adapted to the treated area and light-cured. After thermocycling, the bond strengths were determined by testing the specimens in shear. Field Emission SEM examinations were carried out to evaluate the effects of different treatments on the dentin-resin interface.Statistical analysis revealed that the application of One-Step resulted in similar mean shear bond strengths for the groups in which moisture was present on the dentin surface (12.0-14.2 MPa). The mean shear bond strengths for the group in which One-Step was applied to a dried dentin surface was significantly lower (6.0 MPa). For PrimeBond 2.1, the application of a re-wetting solution significantly increased mean shear bond strengths (13.9 MPa). The remaining three PrimeBond 2.1 groups yielded statistically similar mean bond strengths, regardless of the surface condition (6.6-8.1 MPa).

This article describes how at-home bleaching procedures affect teeth and restorative materials. Specifically, it discusses the effects of tooth-whitening systems on enamel surfaces, enamel and dentin bond strengths, marginal integrity, color, and other properties of restorative materials.

Several "one-bottle" dental adhesives recently have been introduced. These contain hydrophilic resin monomers that should readily wet tooth surfaces. Most also contain solvents that could increase enamel bond strengths by driving out residual moisture from enamel and increasing resin penetration. The purpose of this study was to evaluate bond strengths obtained by six one-bottle bonding agents and one conventional unfilled resin (control).Seventy bovine teeth were randomly assigned to seven groups of 10. Enamel was etched for 15 s with 35% phosphoric acid. Following application of the adhesive, composite resin was bonded using a gelatin capsule technique. Shear bond strengths to enamel were determined.Mean bond strengths ranged from 14.2 MPa for Syntac Single-Component to 27.8 MPa for Single Bond. The mean for Syntac Single-Component was significantly less than that of all other systems tested.The results of this study indicate that one-bottle bonding agents, with the exception of the Syntac material, provide enamel bond strengths at least equal to that of a conventional unfilled resin.

The acid-etch technique for bonding composite resins to enamel has revolutionized the practice of pediatric restorative dentistry. Although bonding resins to dentin has proved to be a difficult challenge, ongoing advances have improved the reliability and predictability of dentinal adhesion. The purpose of this paper is to review the subject of dentin bonding; its development, current status, and clinical methods to improve performance.

This study evaluated the effect of multiple applications of the one-bottle adhesives PrimeBond, One-Step, and Tenure Quik on the shear bond strength of composite to dentin. In addition, the study examined the effects of surface moisture and dual-cure composite on bond strengths of One-Step and Tenure Quik respectively. The adhesive systems were bonded to the occlusal dentin of extracted human teeth. Control group specimens received only two applications of adhesive, as recommended by the manufacturers. Two experimental groups of each system received a greater number of adhesive applications. Additional experimental groups using only two adhesive applications were made to test modifications in surface moisture and composite type for One-Step and Tenure Quik. Shear bond strengths were determined using an Instron Universal Testing Machine. The mean shear bond strength of the PrimeBond control group was significantly greater than that of the other two control groups. Multiple applications of adhesive decreased the bond strength of each system, but the difference was significant only for four applications of One-Step. The method of moisture removal (compressed air or blotting) had no effect on shear bond strength of One-Step. The shear bond strength of Tenure Quik was not affected by the type of composite used. PrimeBond had significantly higher shear bond strengths to dentin than either One-Step or Tenure Quik. Both PrimeBond and One-Step had significantly higher bond strengths than Tenure Quik.

The purpose of this study was to evaluate the effectiveness of various surface treatments used to enhance the bond strength of resin cements to two different laboratory-processed composite resins. Seventy specimens of a microfilled composite resin (Concept) and 70 specimens of a micro-hybrid composite resin (Herculite XRV) were fabricated in metal wells and subjected to heat (250 degrees F) and pressure (85 psi) curing. An additional 70 specimens of each material were fabricated in the shape of disks and also subjected to the same heat/pressure curing. All composite resins were subjected to one of seven treatment regimens. The like-treated specimens were then bonded together using dual-curing resin cement and a uniform seating force (106 gm). After 7 days, bonded specimens were thermocycled 1000 times at 5 and 55 degrees C, and debond shear strengths were determined on a Universal Testing Machine. The use of microabrasion (50 microns aluminum oxide at 60 psi) and ceramic layer deposition (30 microns aluminum oxide with a ceramic additive at 75 psi) consistently improved the shear bond strength of the resin cements to both composite resins. The other treatment combinations provided varying effects. In conclusion, microabrasion or ceramic layer deposition are preferred methods to enhance the bond of resin cements to composite resins.

To evaluate the effects of surface moisture and material viscosity on the shear bond strength of resin-modified glass ionomers to dentin.Sixty human teeth were mounted in phenolic rings and ground to obtain flat facial and lingual dentin surfaces. The specimens were assigned to six treatment groups. Three groups were first conditioned with 10% polyacrylic acid. On one surface of each specimen, dentin was left visibly moist prior to application of the restorative material. On the opposite surface the dentin was dried, but not desiccated, after conditioning. For these three groups, Fuji II LC resin-modified glass ionomer was mixed at powder/liquid (P/L) ratios of 1.4, 3.0 and 3.6 and applied to the conditioned dentin in 2.5 mm diameter molds. The other three groups were treated with Vitremer primer. One surface of each specimen was "dry" and one surface was "moist" before primer application. Vitremer restorative material was mixed at P/L ratios of 2.2, 2.5 and 2.8 and applied to the primed surfaces. Shear bond strengths were measured using a universal testing machine. Data were subjected to three-way ANOVA and Tukey's multiple comparisons test.Mean shear bond strengths of the two materials ranged from 6.9 to 10.4 MPa and varied little regardless of the viscosity of the materials or the degree of surface moistness. The differences among viscosities and surface moistness were not statistically significant. IN this in vitro study, the shear bond strengths of two resin-modified glass ionomers were unaffected by the viscosity of the materials and the surface moisture of the dentin substrate.

To evaluate the effect of a low-viscosity surface-penetrating sealant on microleakage around Class V restorations.Box-shaped Class V preparations were made in the facial and lingual surfaces of 50 extracted human teeth. Occlusal margins were in enamel and gingival margins were in dentin/cementum. Preparations were restored with the following systems (n = 20): Dentin Conditioner + Fuji II LC; ProBond primer + VariGlass VLC; OptiBond + XRV Herculite; Scotchbond Multi-Purpose + Silux Plus; and Scotchbond Multi-Purpose + Restorative Z100. Half of the restorations in each group were randomly selected and sealed with Fortify resin immediately after finishing and polishing. Specimens were thermocycled 500x between 5 degrees and 55 degrees C and subjected to a silver nitrate microleakage test. Penetration of the silver nitrate tracer was evaluated and recorded using a 0-4 ordinal scale. Data were analyzed using non-parametric statistical tests.All of the restorative systems had very little leakage at enamel margins, regardless of whether the resin sealant was used. Each of the systems except VariGlass had minimal leakage at unsealed dentin margins also. Application of the resin sealant significantly reduced leakage at the interface between VariGlass and dentin or cementum, but had no effect on the other restorative systems.

To determine whether the use of low-viscosity intermediate resins (LVR) reduces microleakage of dental adhesive systems.Wedge-shaped Class V cavities were prepared in sound extracted molars. Occlusal margins were in enamel and gingival margins were in dentin/cementum. Five adhesive systems (All-Bond 2, Clearfil Liner Bond 2, OptiBond, PrimeBond and Scotchbond Multi-Purpose) were applied to the preparations strictly according to manufacturers' directions on one side of the tooth and with the addition of LVR (OptiBond FL Adhesive or Protect Liner F) on the other. All cavities were restored with Z100 resin composite. Specimens were then stored in water at 37 degrees C for 24 hours, thermocycled 800x, stained with silver nitrate, sectioned, and evaluated for leakage. Marginal penetration of silver nitrate was scored on 0-3 scale.Statistical analysis (Kruskal-Wallis non-parametric ANOVA) revealed a significant difference (P0.0001) in leakage at dentin margins. Multiple pairwise comparisons of control groups revealed considerable overlapping between groups, but with a trend toward less leakage by OptiBond and Clearfil Liner Bond 2. Leakage of Scotchbond Multi-Purpose was significantly reduced when Protect Liner F was used.

The primary advantages of glass ionomer restorative materials are adhesion to tooth structure and release of fluoride. A new material has been recently introduced for the restoration of cervical lesions and Class I defects in primary teeth. The material combines the properties of glass ionomers with the advantages of a single-component, light-activated composite resin and is known as a "compomer". This new material contains two resins, instead of the acidic polymers found in conventional glass ionomers. The restorative material releases fluoride and can be infected directly into the cavity. With its own bonding agent, the compomer offers a simple and relatively rapid technique. The learning objective of this paper is to describe the utilization of the new restorative material in conjunction with a bonding agent to restore conservative cavity preparations in primary molars. Two clinical cases are used to illustrate the presentation.

To evaluate the bonding between resin composites and resin-modified glass ionomer restorative materials.Bar-shaped specimens of Fuji II LC, Photac-Fil, and Vitremer were fabricated in a mold. After application of unfilled resin, resin composite (either Silux Plus or Restorative Z100) was condensed into the mold against the glass ionomer substrate and was light-cured. These bonded specimens, as well as intact specimens of each material, were placed on a three-point bending apparatus and were loaded until failure using a Zwick testing machine. The transverse strength of each specimen was calculated.Mean transverse strengths of bonded specimens ranged from 50% to 78% of the transverse strength of the intact glass ionomer materials. The lowest transverse strength was 18.1 MPa, for Photac-Fil/Z100, and the highest was 29.6 MPa, for Fuji II LC/Silux. Statistical analysis indicated that the type of composite used had no significant effect on transverse strength. However, the type of resin-modified glass ionomer used was significant. Although there was much overlap between materials, bonded specimens made with Fuji II LC had the highest absolute strength, and those made with Photac-Fil had the lowest absolute strength. Bonded Vitremer specimens had the highest transverse strength relative to the cohesive strength of the material.

The development of adhesive agents for bonding composite to dentin has rapidly evolved in recent years. It is postulated that dentin bond strengths in the range of 17 MPa are sufficient to resist the polymerization shrinkage of composite resins. The purpose of this study was to evaluate the shear bond strengths of the following dentin adhesive systems: All-Bond 2 (Bisco), Imperva Bond (Shofu), Optibond (Kerr), Permagen (Ultradent), ProBond (Caulk/Dentsply), and Scotchbond Multi-Purpose (3M). Sixty human molars (10 per group) were mounted in phenolic rings, and the occlusal surfaces were flat ground in dentin to 600 grit. The prepared dentin bonding sites were treated according to the directions for each of the systems evaluated. A gelatin capsule technique was used to bond Bis-Fil composite cylinders to the teeth. The specimens were stored in water at 37 degrees C for 24 hours. Mean shear bond strengths were as follows: Scotchbond Multi-Purpose: 23.1 +/- 2.6 MPa, All-Bond 2: 21.4 +/- 7.8 MPa, Imperva Bond: 19.8 +/- 6.1 MPa, Optibond: 19.7 +/- 3.6 MPa, ProBond: 16.3 +/- 4.5 MPa, and Permagen: 16.2 +/- 3.0 MPa. There was not a significant difference (P0.05) in the bond strengths of Scotchbond Multi-Purpose, All-Bond 2, Imperva Bond, and Optibond. The bond strengths of Scotchbond Multi-Purpose and All-Bond 2 were significantly greater (P0.05) than ProBond and Permagen. Current-generation dentin adhesive systems have approached or exceeded the theoretical threshold value to resist contraction stresses during polymerization of resin materials.

The acid-etch technique for bonding composite resins to enamel has revolutionized the practice of restorative dentistry. The ability of clinicians to bond restorative materials to enamel has fundamentally changed such diverse areas as cavity preparation, caries prevention, and esthetic treatment options. Although bonding of resin to dentin has proved to be a difficult challenge, ongoing advances are improving the reliability and predictability of dentinal adhesion. The purpose of this article is to provide a brief history of enamel and dentinal bonding, as well as an overview of the current state of the art.

To evaluate the use of a silane coupling agent (Silane Bond Enhancer) for repair of a glass-filled hybrid resin composite (Herculite XR).Composite specimens (n = 20) were either air-abraded (AA) with an intraoral sandblaster (Microetcher), etched with 9.6% hydrofluoric acid (HF) (Porcelain Etch Gel), or treated with both methods (AA/HF). A silane coupling agent was applied to half of the specimens after these initial surface treatments. Composite repairs were completed by application of a phosphonate ester bonding agent (Bondlite) and resin composite (XRV Herculite). Transverse strengths of repaired specimens and intact (control) specimens were determined using an Instron.The mean bond strengths of repaired specimens ranged from 41% to 62% of the composite's cohesive strength. All repair strengths were significantly lower than the cohesive strength, but were not significantly different from each other. Silanation slightly improved the transverse strength of specimens repaired using the HF and AA/HF methods, but not those repaired using the AA procedure.

To evaluate the effects of wet and dry bonding on microleakage of Class V composite restorations.Cavity preparations were made in the buccal and lingual surfaces of 25 extracted human third molars. Half of each preparation was in enamel and the other half was in cementum/dentin. The preparations were randomly assigned to five groups for bonding with Scotchbond Dual-Cure (control), Scotchbond Multi-Purpose, or All-Bond 2. Scotchbond Multi-Purpose and All-Bond 2 were applied using both wet and dry techniques. All preparations were restored with a microfill composite after bonding. The specimens were thermocycled 300 times between 5 degrees and 55 degrees C and were subjected to a silver nitrate staining technique to detect marginal leakage.Specimens bonded with All-Bond 2 and Scotchbond Multi-Purpose had significantly less leakage than the control. However, there was no statistically significant difference between wet and dry bonding techniques for either material.

This study used scanning electron microscopy (SEM) to evaluate the effects of various acid conditioners (etchants) on dentine surfaces. The conditioners completely removed the smear layer from dentine and opened the dentinal tubules, but some also left debris or a reaction product on the surface. The study also evaluated the resin-dentine interfaces produced by five new-generation dentine bonding systems: All-Bond 2, Amalgambond, Gluma 2000, OptiBond, and Scotchbond Multi-Purpose. All-Bond 2, Amalgambond, OptiBond, and Scotchbond Multi-Purpose formed acid-resistant hybrid layers and intra-tubular resin tags when they were applied to visibly moist dentine.

The shades of several resin composite materials are keyed to the Vita Lumin shade guide. This study was designed to determine whether different composites of the same designated Vita shade were actually similar in color. A small-area colorimeter was used to compare the L*a*b* color parameters of three hybrid resin composites--Pertac-Hybrid, Prisma AP.H, and XRV Herculite. Four Vita shades (A2, B3, C2, and D3) of each material were evaluated. Color differences (delta E values) between composites of the same designated shade ranged from 2.07 for the A2 shades of Herculite and AP.H to 7.64 for the D3 shades of Herculite and Pertac. Color differences in this range are perceptible to many observers under ideal viewing conditions.

This study evaluated the shear bond strengths of a phosphate ester bonding agent, Clearfil Photo Bond, using different phosphoric acid gels to etch dentin. The study also tested the shear bond strength of the Clearfil Liner Bond system. Sixty extracted human molars were ground to expose mid-coronal dentin and were randomly assigned to six treatment groups. The first group was left unetched as a control. In the next four groups, dentin was etched with phosphoric acid gels: K-etchant (40% with silica thickener); Uni-Etch (polymer-thickened 32%); All-Etch (10%, polymer thickener); or Ultra-Etch (10%, silica thickener). Specimens in the sixth group were etched with 10/20 Ca, a gel with 10% citric acid and 20% calcium chloride. All specimens were bonded with Clearfil Photo Bond and XRV Herculite resin composite. Specimens in the final group also received SA Primer and Protect Liner. After thermocycling, shear bond strengths were determined using an Instron universal testing machine. Mean shear bond strengths ranged from 1.3 MPa (control) to 15.9 MPa (Clearfil Liner Bond). The shear bond strengths of specimens that had been etched with phosphoric acid gels were in the range of 5-8 MPa, and were not significantly affected by either acid concentration or thickener type. SEM examination showed that phosphoric acid demineralized dentin to a depth of 5 microns, while 10/20 Ca demineralized dentin to a depth of only 1-1.5 microns.

This in vitro study examined the effects of chlorhexidine on dentin surfaces and on the bond strengths of composite to dentin. Scanning electron microscopy revealed that the chlorhexidine solution deposited debris on the surface and within the tubules of etched dentin but chlorhexidine had no significant effect on the shear bond strengths of composite to dentin using the All-Bond 2 adhesive system.

This study evaluated the shear bond strengths of resin composite to dentin using Kanca's "total-etch" technique (etching with 37% phosphoric acid, application of Tenure Solutions A and B, and application of Scotchbond 2 Adhesive). Bonding was done under different conditions, to specimens with or without hydrostatic pressure. Shear bond strengths were 20.1 MPa to dentin under simulated physiologic pressure, and 15.2 MPa to dentin without pressure.

This in vitro study evaluated the microleakage of Class V resin composite restorations bonded with All-Bond 2 Universal Dental Adhesive and Scotchbond Multi-Purpose Dental Adhesive System. For comparison, other restorations were placed with Scotchbond 2 Light Cure Dental Adhesive or with no bonding agent. Class V cavities were restored with either one or two increments of resin composite to determine whether the restorative method affected microleakage. A silver nitrate staining technique was used to detect marginal leakage. There was no leakage at the etched enamel margins in any treatment group. All-Bond 2 had significantly less leakage at the gingival margins than the other two dentin adhesives. Scotchbond Multi-Purpose had less leakage than Scotchbond 2, which was not statistically different from the control (no bonding agent). Incremental filling significantly reduced leakage only in the control group.

This study evaluated the effects of etching time on bond strengths of composite to enamel. Proximal surfaces of extracted molars were etched with either a conventional etchant (35% phosphoric acid) or one of two dentin/enamel conditioners, 10% maleic acid (Scotchbond Multi-Purpose Etchant), or a solution of oxalic acid, aluminum nitrate, and glycine (Gluma 12 Conditioner). Each agent was applied for 15, 30, or 60 seconds. Specimens etched with 35% phosphoric acid had the highest mean bond strengths at each etching time. At the manufacturer's recommended application times, the other two agents gave significantly lower shear bond strengths than phosphoric acid.

Recently, simple radiometers for measuring the intensity of dental curing lights have been introduced. This study examined the relationship among light intensity measurements by three radiometers, distance of curing tip from composite resin, and resin polymerization (as indicated by microhardness). Light intensity measurements, which decreased with increasing distance from the curing tip, were strongly correlated with composite resin hardness. Reduced light intensity produced softer composite resin, particularly on the bottom of specimens (2-mm depth). The different radiometers provided similar indications of the changes in light intensity at various curing distances.

This double-blind, randomized, controlled clinical trial was designed to evaluate the efficacy and soft tissue effects of nightguard (mouthguard) vital bleaching. Subjects were assigned to one of two treatment groups, overnight (insertion of mouthguard at bedtime) or 3-hour (replenishment of test solution at hourly intervals for a total of 3 hours exposure daily). The experimental solutions included two products that are specifically designed for tooth bleaching, one product that is marketed as an oral antiseptic, and a control solution (glycerin). Each subject participated for a 3-week period. Tooth color analysis (shade determination) was done at baseline and the end of the treatment. Gingival and Plaque Indices were recorded at baseline and at the end of each week of study. Results indicated that the bleaching treatment was effective in most cases and caused no tissue inflammation or significant tooth sensitivity. The mean Gingival and Plaque Indices were generally lower (denoting improvement) at the end of treatment. Patient satisfaction with the procedure was high.

Many dental adhesive systems now rely on simultaneous etching of enamel and dentin. Instead of the traditional 35-40% phosphoric acid, new etchants (including 10% maleic acid, 10% phosphoric acid, and oxalic acid/aluminum nitrate) are used. This in vitro study determined the shear bond strengths of resin composite to enamel which was etched with these agents according to manufacturers' instructions. The control etchant, 35% phosphoric acid, gave a mean bond strength of 24.5 MPa. 10% maleic acid and 10% phosphoric acid had significantly lower shear bond strengths (13.2 MPa). Gluma 12 Conditioner (oxalic acid/aluminum nitrate) had a mean bond strength of 6.3 MPa, which was significantly less than the other etchants. Bond strengths for each etchant were not affected by the type of unfilled resin used.

This in vitro study evaluated the shear bond strengths of five adhesive systems bonded to dentin with and without simulated physiologic hydrostatic pressure. To simulate pulpal pressure, bonding procedures were done on extracted teeth connected to a hydration apparatus. Bond strengths were significantly less for each adhesive system under simulated physiologic conditions. Amalgambond had significantly higher bond strengths than Clearfil Photo Bond, Gluma, Scotchbond 2, or Tenure, either with or without simulated pulpal pressure.

An earlier study showed that Scotchbond Multi-Purpose, which uses a 10% maleic acid dentin/enamel etchant, had lower enamel bond strengths than those typically obtained by etching with 35-40% phosphoric acid. Therefore, the possibility of substituting phosphoric acid for maleic acid in the Scotchbond system might be considered. The purpose of this study was to evaluate the dentin bond strengths of Scotchbond Multi-Purpose when various phosphoric acid agents were used to etch the dentin. Proximal dentin surfaces of extracted human molars were etched with 10% maleic acid, 35% phosphoric acid, 32% phosphoric acid, 10% phosphoric acid or 25% phosphoric acid with aluminum oxalate (Etch 'N' Seal). Scotchbond Multi-Purpose Primer and Adhesive were applied as directed and composite posts were bonded to the dentin. After thermocycling, the composite was fractured off using an Instron testing machine. Mean dentin bond strengths were 17.3 MPa for 10% maleic acid, 17.2 MPa for 10% phosphoric acid, 15.2 MPa for 35% phosphoric acid, 13.6 MPa for 32% phosphoric acid, and 5.2 MPa for Etch 'N' Seal. The bond strengths for all groups except Etch 'N' Seal were statistically similar.

A number of home bleaching products have recently been introduced. This in vitro study evaluated the effect of three representative bleaching products on the microhardness and surface texture of hybrid and microfilled composite resins. Scanning electron microscopic examination revealed cracking of the microfilled specimens treated with carbamide peroxide gels (Proxigel and WhiteBrite). WhiteBrite also caused slight roughening of the hybrid composite resin. Microhardness tests indicated that the treated composite resins became somewhat softer. However, the only statistically significant softening was associated with WhiteBrite.

Some clinicians now advocate dentinal etching to eliminate microleakage around composite resin margins. This study evaluated the "Kanca technique" and three commercial dentinal adhesives, including Clearfil Photo Bond, which uses phosphoric acid to etch dentin. The Kanca technique and Tenure were the most effective systems tested. However, none of the bonding systems completely eliminated microleakage. Total sealing of dentinal margins is not predictable with current adhesives and composite resins.

Internal bleaching is frequently used to treat discolorations of endodontically treated teeth, and home bleaching of stained vital teeth has also become popular. This article describes a case in which carbamide peroxide home bleaching was used to enhance the appearance of an internally bleached, endodontically treated tooth.

This study evaluated the effects of a dentin bonding system and glass ionomer liner on in vitro recurrent caries around resin composite restorations in dentin. The dentin adhesive significantly reduced the size of recurrent lesions. The glass ionomer liner, applied either to the axial wall or to the cavosurface margin, provided an even greater cariostatic effect. Both the adhesive and the liner reduced the size of cavity wall lesions. In addition, zones of caries inhibition were present around 75% of restorations lined with glass ionomer cement.

This article reviews the literature concerning the pulpal effects of composite resin restorations. A number of aspects are addressed, including the composite resin materials themselves, bacterial leakage, acid-etch technique, and dentin bonding procedures. Guidelines for pulpal protection are discussed.