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Surface Preparation (surface + preparation)
Selected AbstractsImproved bonding of adhesive resin to sintered porcelain with the combination of acid etching and a two-liquid silane conditionerJOURNAL OF ORAL REHABILITATION, Issue 1 2001H. Kato This study determined the bond strengths of adhesive resins joined to a feldspathic porcelain (VMK 68) for the purpose of developing the most durable surface preparation for the porcelain. Three porcelain surfaces,ground, air-abraded with alumina, and etched with hydrofluoric acid,were prepared. A two-liquid porcelain conditioner that contained both 4-methacryloyloxyethyl trimellitate anhydride (4-META) and a silane coupler (Porcelain Liner M) was used as the priming agent. Each of the two liquid components of the conditioner was also used individually in order to examine the effects of the respective chemical ingredients on adhesive bonding. Two methyl methacrylate (MMA)-based resins initiated with tri- n -butylborane (TBB) either with or without 4-META (MMA-TBB and 4-META/MMA-TBB resins) were used as the luting agents. Shear bond strengths were determined both before and after thermocycling. Shear testing results indicated that thermocycling was effective for disclosing poor bonding systems, and that both mechanical and chemical retention were indispensable for bonding the porcelain. Of the combinations assessed, etching with hydrofluoric acid followed by two-liquid priming with the Porcelain Liner M material generated the most durable bond strength (33·3 MPa) for the porcelain bonded with the 4-META/MMA-TBB resin (Super-Bond C&B). [source] Effect of etching and sandblasting on bond strength to sintered porcelain of unfilled resinJOURNAL OF ORAL REHABILITATION, Issue 2 2000H. Kato This study determined the bond strength of an unfilled resin joined to a feldspathic porcelain for the purpose of evaluating the retentive performance of the prepared material surfaces. Porcelain disks (VMK 68 dentin) were either air abraded with alumina (AAA) or etched with one of the following five etchants: (1) ammonium hydrogen bifluoride (AHB); (2) acidulated phosphate fluoride (APF); (3) hydrofluoric acid (HFA); (4) phosphoric acid (PHA); and (5) sulfuric acid-hydrofluoric acid (SHF). Specimens ground with abrasive paper were also used as controls. After surface preparation, the two different sized porcelain disks were bonded together with a methyl methacrylate-based resin initiated with tri- n -butylborane (MMA-TBB resin). Shear bond strengths were determined both before and after thermocycling. Before the thermocycling, the greatest bond strengths (21·3 and 23·7 MPa) were generated with the use of the SHF and HFA agents, followed by the AHB agent (18·4 MPa). Reduction in bond strength after thermocycling was significant for all groups, although the SHF- and HFA-treated groups exhibited bond strengths greater than 15 MPa even after the thermocycling. The results indicated the effectiveness of the SHF- or HFA-etching for retaining the acrylic resin to the porcelain. However, ageing testing also revealed insufficient retentive characteristics of the acrylic resin by etching alone. [source] Defect density dependence of carrier dynamics in AlGaN multiple quantum wells grown on GaN substrates and templatesPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 7 2005G. A. Garrett Abstract Subpicosecond time-resolved photoluminescence (TRPL) has been used to compare the room temperature carrier dynamics in Al0.1Ga0.9N/Al0.3Ga0.7N multiple quantum well (MQW) structures simultaneously deposited on a high quality free standing HVPE GaN substrate (dislocation density ,1 × 107cm,2) and 1 µm MOCVD GaN template on sapphire. The PL lifetime of ,500 ps in the MQW on GaN substrate is about 5 times longer than that for the MQW on GaN template, with a concomitant increase in CW PL intensity. This behavior is attributed primarily to an increase in nonradiative lifetime associated with a 100 times reduction in dislocation density in the GaN substrate. The observation that the PL lifetime in the MQW falls short of the ,900 ps dominant decay time in the GaN substrate may be indicative of generation of additional defects and dislocations due to substrate surface preparation, strain relaxation, and nonoptimal growth temperature associated with the difference in heating of the thin GaN template on sapphire and the thick GaN substrate. An extended PL rise time of greater than 20 ps for the MQW emission when above barrier pumping is employed implies that both wells and barriers are of high quality. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Microleakage of composite resin restorations in cervical cavities prepared by Er,Cr:YSGG laser radiationAUSTRALIAN DENTAL JOURNAL, Issue 2 2008S Shahabi Abstract Background:, Evaluation of microleakage is important for assessing the success of new methods for surface preparation and new adhesive restorative materials. The aim of this laboratory study was to assess microleakage at the margins of composite restorations in Er,Cr:YSGG laser prepared cavities on the cervical aspects of teeth by means of dye penetration, and compare this with conventionally prepared and conditioned cavities. Methods:, Class V cavities were produced on sound extracted human teeth, which had been assigned randomly to one of three groups (N = 10 each), as follows: Group 1 , prepared using a diamond cylindrical bur and then treated with 37% phosphoric acid; Group 2 , irradiated with an Er,Cr:YSGG laser (Biolase Waterlase) and then treated with 37% phosphoric acid; Group 3 , irradiated only with the laser. After application of bonding agent (Excite, Ivoclar Vivadent), all cavities were restored with composite resin (Heliomolar). After polishing the restorations, the teeth were thermocycled from 5,50°C for 500 cycles. Dye leakage was assessed after immersion in methylene blue, by examining longitudinal sections in a stereomicroscope at ×30 magnification. Results:, The extent of dye penetration was lowest in the laser only group (Group 3). Penetration of dye to dentine and axial walls occurred in 80 per cent of conventionally prepared (bur + acid) specimens, but in the laser group, dye penetration to the axial wall occurred in only 30 per cent of cases. There was a strong statistical association between treatment group and the distribution of microleakage scores (Chi-square, P = 0.0023). Conclusions:, For Class V cavities, with the adhesive materials employed, higher microleakage occurs with phosphoric acid etching of bur- or laser-cut surfaces, than with the surface created by use of the laser alone without additional conditioning. [source] Adhesive bonding of titanium,aluminum,niobium alloy with nine surface preparations and three self-curing resinsEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 2 2003Hiroaki Yanagida The purpose of the current study was to evaluate the adhesive performance of metal conditioners when used for bonding between auto-polymerizing methacrylic resins and a titanium alloy. Disk specimens were cast from a titanium,aluminum,niobium (Ti,6Al,7Nb) alloy, air-abraded with alumina, and bonded with 24 combinations of eight metal conditioners (Acryl Bond, ACB; All-Bond 2 Primer B, ABB; Alloy Primer, ALP; Cesead II Opaque Primer, COP; Metafast Bonding Liner, MBL; Metal Primer II, MPII; MR Bond, MRB; Super-Bond liquid, SBL) and three autopolymerizing methacrylic resins (Repairsin, RE; Super-Bond C & B, SB; Tokuso Rebase; TR). Unprimed specimens were used as controls. Shear bond strengths were determined both before and after thermocycling (4,60°C, 20, 000 cycles). The ALP-SB group recorded the greatest post-thermocycling bond strength (21.8 MPa) followed by the COP-SB group (17.8 MPa) and the MPII-SB group. The post-thermocycling bond strengths of the unprimed-SB group and the ALP-RE group were statistically comparable. No significant differences were found among the nine TR resin groups, and these groups showed the lowest bond strength. In conclusion, the use of one of the three conditioners (ALP, COP, and MPII) in combination with the SB resin is recommended for bonding the Ti,6Al,7Nb alloy. [source] Adhesive bonding of composite material to cast titanium with varying surface preparationsJOURNAL OF ORAL REHABILITATION, Issue 2 2002H. Yanagida The purpose of the present study was to evaluate the surface preparation effects of eight metal conditioners and an adhesive system on bonding between a prosthodontic composite material and cast titanium. Eight primers designed for conditioning base metal alloys (Acryl Bond, All-Bond 2 Primer B, Alloy Primer, Cesead II Opaque Primer, Eye Sight Opaque Primer, Metafast Bonding Liner, Metal Primer II, and MR Bond) as well as a surface modification technique (Siloc) were assessed. Disk specimens cast from titanium (T-Alloy H) were either primed with one of the eight primers or treated with the Siloc system, and then bonded with a light-activated composite material (Artglass). Bond durability was evaluated by thermocycling (4 and 60 °C, 1 min each, 20 000 cycles). After thermocycling, two groups either primed with the Cesead II Opaque Primer material or treated with the Siloc system exhibited significantly greater bond strength (20·0 and 19·0 MPa) than the other groups (0·2,12·6 MPa, P < 0·05). These two systems are considered to be useful for improving bonding between the titanium and the composite material tested. [source] | ||||||||||