Contract Management Process Maturity:' Analysis of Recent Organizational Assessments

Symposium Presentation (for Acquisition Research Program)Symposium PresentationNaval Postgraduate School Acquisition Research ProgramApproved for public release; distribution is unlimited

Microtensile bond strengths of seven dentin adhesive systems

Objectives. The purpose of this study was to evaluate the microtensile bond strengths of seven dentin adhesive systems (Solid Bond, EBS-Multi, PermaQuik, One Coat Bond, Gluma One Bond, Prime & Bond NT/NRC and Clearfil Liner Bond 2V) and their respective fracture modes. Methods. Superficial occlusal dentin of extracted human molars was exposed, finished with wet 600-grit silicon carbide paper, and a block of resin composite bonded with the above adhesives according to the manufacturers' instructions. The teeth were kept in tap water for 24 h at 37°C, sectioned to obtain three or four bar-shaped specimens, which were then shaped to an hour-glass form of 1.2 ± 0.02 mm diameter. The specimens were stressed at a crosshead speed of 1 mm/min until rupture of the bond. The mean bond strengths were compared using one-way ANOVA and LSD tests. The frequency of fracture modes was compared using Kruskal-Wallis and Mann-Whitney U-tests. Results. Mean microtensile bond strengths ranged from (17.8 ± 7.0) MPa for Solid Bond to (36.0 ± 8.1) MPa for Clearfil Liner Bond 2V. The bond strength of Clearfil Liner Bond 2V and PermaQuik (30.8 ± 8.5 MPa) were not significantly different, and were higher than all other materials. Bond strengths of Solid Bond (17.8 ± 7.0) MPa, EBS-Multi (18.7 ± 5.0) MPa, One Coat Bond (21.9 ± 5.6) MPa, and Gluma One Bond (23.4 ± 5.2) MPa were not significantly different. SEM examination indicated that Solid Bond, EBS-Multi and One Coat Bond showed no significant difference in failure modes but were significantly different from PermaQuik, Prime & Bond NT/NRC and Clearfil Liner Bond 2V. Significance. The self-etching primer system, Clearfil Liner Bond 2V, provided the simplest bonding technique, and together with PermaQuik exhibited greatest bond strength to dentin. © 2000 Academy of Dental Materials. Published by Elsevier Science Ltd. All rights reserved.link_to_subscribed_fulltex

Microtensile bond strengths of glass ionomer (polyalkenoate) cements to dentine using four conditioners

Objectives: The purpose of this study was to measure the microtensile bond strengths of three glass ionomer cements to dentine (Photac-Fil Quick; Fuji II LC; Fuji IX GP) using four different conditioners (Ketac Conditioner; Dentin Conditioner; Cavity Conditioner; and an experimental conditioner, K-930). Methods: Superficial occlusal dentine of extracted human third molars was exposed, finished with wet 600-grit silicon carbide paper, and each of the above glass ionomer cements bonded using the four conditioners according to the manufacturers' instructions. After 24 h in tap water at 37°C, the teeth were sectioned to obtain 3-4 bar-shaped specimens. Ten specimens were prepared for each group and shaped to an hour-glass form of (1.2 ± 0.02) mm diameter. The specimens were mounted in ajig and stressed in tension at a crosshead speed of 1 mm/min until failure. The mean bond strengths were calculated and compared using one-way ANOVA and LSD tests, and the fracture modes were examined by scanning electron microscopy. Results: Mean microtensile bond strengths for Photac-Fil Quick were not significantly different from Fuji II LC for each of the conditioners used. However, the bond strengths for Photac-Fil Quick were significantly greater than Fuji II LC when no conditioner was applied. Mean microtensile bond strengths of conditioned specimens of Fuji II LC were significantly greater than non-conditioned specimens. Mean microtensile bond strengths of non-conditioned specimens of Fuji IX GP were not significantly different from conditioned specimens. The fracture mode of all specimens demonstrated mostly cohesive failure within the cement. Significance: The use of surface conditioners resulted in improvement in bond strength of Fuji II LC, while Photac-Fil Quick and Fuji IX GP showed no difference. © 2000 Elsevier Science Ltd. All rights reserved.link_to_subscribed_fulltex

Field-emission scanning electron microscopy of resin-dentin interface morphology of seven dentin adhesive systems

Purpose: The purpose of this study was to evaluate the resin-dentin interface morphology of 7 resin-based dentin adhesive systems (Solid Bond, EBS-MuIti, PermaQuik, One Coat Bond, Gluma One Bond, Prime & Bond NT/NRC, and Clearfil Liner Bond 2V). Materials and Methods: Fourteen dentin disks 1.0 mm thick were obtained from superficial occlusal dentin of extracted human third molars, and finished with wet 600-grit silicon carbide paper. Two dentin disks were bonded using each of the adhesives above according to the manufacturers' instructions, and a thin layer of flowable resin composite was applied. The specimens were kept in tap water for 24 h at 37°C, and then assigned to one of two observational techniques: a fracture technique and an acid-base technique. Fracture technique: shallow grooves were cut, fixed in 10% buffered formalin, and dehydrated in an ascending ethanol series up to 100%, critical-point dried, and fractured along the prepared grooves. Acidbase technique: the specimens were embedded in epoxy resin, sectioned through the center, polished with diamond paste down to 0.25-um particle size, and treated with 10% orthophosphoric acid for 10 s and 5% sodium hypochlorite for 5 min. All the specimens were mounted on aluminum stubs, gold sputter coated, and observed using field-emission scanning electron microscopy (FE-SEM). Results: All the dentin adhesive systems showed hybrid layer formation, but the thickness varied depending on the bonding system used. The self-etching priming systems (Prime & Bond NT/NRC and Clearfil Liner Bond 2V) showed the thinnest hybrid layer at 1 to 2 urn, whereas the "single-bottle" system (Gluma One Bond) exhibited the thickest hybrid layer at 8 to 16 urn. Conclusion: The ultramorphological structures of dentin bonding systems are determined by the composition of each system. Characterization of the interface of the adhesive system using the fracture technique provides additional information regarding the pattern of resin infiltration in some dentin bonding systems.link_to_subscribed_fulltex

Microtensile bond strengths to caries-affected dentine treated with Carisolv®

Background: Little information is available regarding the bonding performance of adhesive restorative materials to caries-affected dentine after the use of Carisolv®. The aim of this study was to compare the microtensile bond strengths of two resin-based adhesives, a conventional glass ionomer cement and resin modified glass ionomer cement to 'normal' dentine and caries-affected dentine after Carisolv treatment. Methods: Specimens were prepared using molar teeth with small carious lesions. Caries was removed with the Carisolv® solution and the whole surface was bonded with either SE Bond, One Coat Bond, Fuji IX or Fuji II LC. After 24 hours, specimens were prepared for the microtensile bond strength test and stressed in tension at 1mm/min until rupture of the bond. Mean bond strengths and mode of failure were determined and analysed with the LSD test and chi square test respectively. Results: The results showed no statistical difference for SE Bond, One Coat Bond or Fuji IX, but a difference was observed for the resin-modified GIC, Fuji II LC. Conclusions: It was concluded that carious dentine treated with Carisolv did not affect the adhesion of the adhesive restorative materials tested in this study with the exception of Fuji II LC.link_to_subscribed_fulltex