Light-cured Adhesives Research Articles

Bonding of Smd Components with Light-Curing Adhesives by Radiation Transmission. Part 1

Bonding of Smd Components with Light-Curing Adhesives by Radiation Transmission. Part 1

Optimizing filler content in an adhesive system containing pre-reacted glass-ionomer fillers

Objectives. (1) To evaluate the optimal concentration of the calcium type pre-reacted glass-ionomer (PRG-Ca) fillers in experimental light-activated adhesives for bonding to tooth substrates and fluoride release; (2) to evaluate the polymerization reactivity of these experimental filled adhesives; and (3) to examine the ultrastructure of the resin–dentin interface bonded with the commercial version of this self-etching adhesive (Imperva Fluoro Bond, Shofu Inc., Kyoto, Japan). Materials and methods. PRG-Ca fillers were prepared from the acid–base reaction of calcium type fluoroaluminosilicate glass with poly(acrylic acid) in water. Different experimental light-cured adhesives were prepared, with 0–57 wt% PRG-Ca fillers and 3 wt% aerosil silica incorporated in a resin matrix. Twenty-four hours shear bond strengths to bovine enamel and dentin were assessed using the adhesive with/or without accelerated aging. The cumulative amount of fluoride released from the cured adhesives and differential scanning calorimetry (DSC) measurements were also conducted. 180-grit SiC paper polished human dentin disks were treated with Imperva Fluoro Bond that contains 17 wt% PRG-Ca fillers and prepared for TEM examination. Results. Increase in PRG-Ca filler content of experimental adhesives was highly correlated with the decrease in bond strengths to dentin ( r=−0.96 to −0.99), the increase in cumulative fluoride release, ( r=0.97) and the decrease in polymerization energy (cal/g) of the adhesives ( r=−0.99) ( p<0.001). A PRG-Ca content of 17 wt% provided optimal bond strength to enamel and dentin after accelerated aging and fluoride release. TEM showed that salt-like matrices were present around the hydrogels and remnant glass cores of the PRG-Ca fillers. The commercial self-etching primer completely dissolved the smear layer and formed 2 μm thick hybrid layers in intact dentin. Significance. The use of silanized PRG-Ca fillers provides good adhesion and a source of fluoride release in a commercially available self-etching adhesive system.

Adverse surface interactions between one-bottle light-cured adhesives and chemical-cured composites

Objectives: This study examined the effect of one-bottle adhesives with different acidities on bonding to chemical-cured and light-cured resin composites. Methods: Twenty-four non-carious human third molars were divided into eight groups. A flat dentin surface was created for each tooth. Acid-conditioned dentin surfaces were bonded with Prime&Bond NT (Dentsply), OptiBond SOLO (Kerr), Single Bond (3M) or One-Step (Bisco). Each adhesive group was covered with composite buildups, using either a light-cured (Z100, 3M) or a chemical-cured composite (BisFil 2, Bisco). Specimens were vertically sectioned into 0.9×0.9 mm beams. Microtensile bond strengths were recorded and failure modes were classified using a stereoscopical microscope. Four representative beams from each group were further prepared for SEM examination. Results: Two-way ANOVA showed that the effect of adhesive types, composite curing modes and their interaction were statistically significant ( P<0.001). Multiple comparison tests revealed no statistically significant difference in the bond strength of the four adhesives with the light-cured composite ( P>0.05). However, they were significantly lower when used with the chemical-cured composite ( P<0.01). A positive correlation was observed between the acidity of adhesives and the bond strengths of the chemical-cured composite. Failure occurred predominantly along the composite-adhesive interface, with microporosities on the adhesive surface and voids within the chemical-cured composite. Significance: Air incorporated during mixing of chemical-cured composites only contributed partially to the decreased bond strength observed in simplified-step adhesives. Ultrastructural observations suggested the presence of a surface interaction between the uncured, acidic resin monomers from the oxygen inhibition layer of the adhesive and the initiator components in the chemical-cured composite.

Rapid curing of bonding composite with a xenon plasma arc light

The use of light-cured orthodontic adhesives is an increasingly popular method for the bonding of orthodontic brackets. However, one of the disadvantages of light-cured adhesives is their long curing times. The xenon plasma arc curing light is purported to dramatically reduce the required curing time. The purpose of this study was to test the efficiency of a xenon plasma arc light versus a conventional tungsten-quartz halogen light in producing effective bond strengths for orthodontic brackets. Standardized brackets were bonded to bovine enamel with 3 different orthodontic bonding materials. The bonding materials were exposed to the tungsten-quartz halogen light for 40 seconds and to the xenon light for 3, 6, and 9 seconds. Bond strength was tested 30 minutes and 24 hours after light-curing. The results showed that bond strength with the application of the xenon light was greater with longer exposures. There were no statistically significant differences between the bond strengths of the brackets exposed to the tungsten-quartz halogen light for 40 seconds and those exposed to the xenon light for 3, 6, or 9 seconds. However, xenon light exposures of 6 or 9 seconds were required to create bond strengths equal to those produced by the tungsten-quartz halogen light. The xenon light produced equivalent bond strengths at very short light exposures. (Am J Orthod Dentofacial Orthop 2001;119:610-6)

Faster electrical potting and sealing with new light curing adhesives

Faster electrical potting and sealing with new light curing adhesives

Torsional bond strength and failure pattern of ceramic brackets bonded to composite resin laminate veneers

The objectives of this study were to investigate the torsional bond strength of ceramic brackets bonded to composite resin veneer laminates and to human enamel. Microfilled resin veneers were bonded directly to prepared, etched bovine teeth embedded in epoxy resin. Brackets [Allure IV (NSB), Fascination, Starfire TMB, and Transcend 2000] were bonded to abraded, acid-etched resin veneers with a light-cured or a chemically-cured adhesive. Brackets were also bonded to human teeth with light-cured and chemically-cured adhesives for comparison purposes. After 24 hours storage in water, specimens were subjected to torsional stress and the maximum shear stress tau max, was calculated. The debonded brackets, the veneer, and enamel surfaces were examined under a stereomicroscope and a SEM to study the failure modes. Three-way ANOVA with a Tukey multiple comparisons test revealed significant differences in bond strengths among bracket types and bonding substrate at P = 0.05 level. Highest bond strength was observed in brackets with a combination of micromechanical retention and chemical adhesion. Significant interactions among bracket, substrate (enamel or resin) and mode of cure of adhesive were observed. Analysis of the failure pattern of brackets revealed adhesive and/or cohesive resin failures in all brackets studied, while cohesive bracket failures occurred in the single-crystal Starfire TMB bracket and the polycrystalline Transcend 2000 bracket. Debonding ceramic brackets under a steady torsional load caused no substrate surface alterations regardless of adhesive used.

Tensile bond strength of orthodontic brackets bonded with a fluoride-releasing light-curing adhesive. An in vitro comparative study

A light-curing, fluoride-releasing adhesive (VP 862, Vivadent, Liechtenstein) for bonding of brackets has been produced for inhibition of white spot lesions during orthodontic treatment. The tensile bond strength after 24 hours and 6 months was investigated and compared with two other light-curing adhesives (Transbond, 3M Corp., Monrovia, Calif., and Heliosit-Orthodontic, Vivadent, Liechtenstein) and two chemical-curing adhesives (Concise, 3M, Monrovia Calif., and Saga Bond, Saga Orthodontics, Kongsvinger, Norway). All adhesives produced adequate strength to be recommended for clinical use. The light-curing adhesives produced slightly lower bond strengths after 24 hours and 6 months, except Transbond, which showed an increase in bond strength in this period approaching the two chemical adhesives.

An Evaluation of Zirconium Oxide Brackets: A Preliminary Laboratory and Clinical Report

A pre-production sample of zirconium oxide (ceramic) brackets was examined in this study. A laboratory investigation of the tensile/peel bond strength of the brackets was carried out using two light-cured adhesives (Prismafil and Heliosit) and one chemically-cured adhesive (Delphic). The mode of failure was also investigated using optical and scanning electron microscopy. The bond strengths achieved with Prismafil were statistically significantly (P less than 0.05) lower than Heliosit and Delphic between which no significant differences were found. All samples failed at the bracket-adhesive interface. A clinical test demonstrated the extreme ease of sliding along stainless steel and nickel-titanium archwires, and revealed a low plaque adhesion. The principal disadvantage of these brackets appears to be their off-white highly opaque appearance which in addition to giving poor aesthetics may adversely affect bond strength with light-cured adhesives.

The use of visible light-curing composites in bonding ceramic brackets

Three hundred and fifty bovine teeth were bonded with a ceramic bracket using nine different materials. Five of the materials were composites used in conservative dentistry, two were light-curing orthodontic adhesive test materials, and two were chemically curing adhesives. Four of the materials were modified by dilution with resin. With the proper consistency, it was found that the use of primer was not necessary. Adequate strength was observed within a 20-second curing time. No statistical difference in bond strength was observed among the materials. It is concluded that light-curing adhesives can offer several advantages in the bonding of ceramic brackets.