Homeopathic Symphytum officinale increases removal torque and radiographic bone density around titanium implants in rats

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of metal conditioners on the adhesive bonding of resin cements to cast titanium

Objective: To assess the effect of metal conditioners on the bond strength between resin cements and cast titanium. Method and Materials: Commercially pure titanium (99.56%) was cast using an arc casting machine. Surfaces were finished with 400-grit silicon carbide paper followed by air abrasion with 50-mu m aluminum oxide. A piece of double-coated tape with a 4-mm circular hole was then positioned on the metal surface to control the area of the bond. The prepared surfaces were then divided into 4 groups (n=10): G1, unprimed Panavia F; G2, Alloy Primer-Panavia F; G3, unprimed Bistite DC; G4, Metaltite-Bistite DC. Forty minutes after insertion of the resin cements, the specimens were detached from the mold and stored in water at 37 C for 24 hours. Shear bond strength was performed in a testing machine (MTS 810) at a crosshead speed of 0.5 mm/min. Data were analyzed using ANOVA and Tukey's test with a .05 significance level. The fractured surfaces were observed through an optical microscope at 10x magnification. Results: the G1 group demonstrated significantly higher shear bond strength (17.95 MPa) than the other groups. G3 (13.79 MPa) and G4 (12.98 MPa) showed similar mean values to each other and were statistically superior to G2 (9.31 MPa). Debonded surfaces generally presented adhesive failure between metal surfaces and resin cements. Conclusion: While the Metaltite conditioner did not influence the bond strength of the Bistite DC cement, the Alloy Primer conditioner significantly decreased the mean bond strength of the Panavia F cement.

THE INFLUENCE of SHORT-HEATING-CYCLE INVESTMENTS on THE QUALITY of COMMERCIALLY PURE TITANIUM CASTINGS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Shear Bond Strength of Different Repair Systems to Titanium After Water Aging

This study evaluated the shear bond strength (SBS) and stability of commercially pure titanium (CP Ti)/repair material interfaces promoted by different repair systems. One hundred CP Ti cast discs were divided into five repair system groups: 1) Epricord (EP); 2) Bistite 11 DC (BT); 3) Cojet (CJ); 4) Scotchbond Multi-Purpose Plus (SB) (control group); and 5) Cojet Sand plus Scotchbond Multi-Purpose Plus (CJSB). The specimens were stored in distilled water for 24 hours at 37 degrees C, thermal cycled (5000 cycles, 5 degrees-55 degrees C) and stored under the same conditions for either 24 hours or six months (n=10). SBS was tested and the data were analyzed by two-way analysis of variance (ANOVA) and Tukey test (alpha=.05). Failure mode was determined with a stereomicroscope (20x). The repair system, storage time, and their interaction significantly affected the SBS (p<0.001). At 24 hours, CJSB exhibited the highest SBS value, followed by CJ. At six months, these two groups had similar mean SBS (p>0.05) and higher means in comparison to the other groups. For both storage times, BT presented the lowest SBS, while the EP and SB groups did not differ significantly from one another (p>0.05). There were no significant differences in SBS between the storage times for the groups EP and CJ (p>0.05). The groups BT, SB, and CJSB showed 100% adhesive failure, irrespective of storage time. The CJSB group showed the highest SBS at both storage times. At six months, the CJ group exhibited a similar SBS mean value when compared to the CJSB group. Water storage adversely affected the groups BT, SB (control group), and CJSB. Considering SBS values, stability, and the failure mode simultaneously, the CJ group showed the best CP Ti repair performance.

Fatigue performance of joints executed in pure titanium structures with several diameters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

THE EFFECT of DIFFERENT SURFACE TREATMENTS on THE SHEAR BOND STRENGTH of LUTING CEMENTS TO TITANIUM

Statement of problem. Although titanium presents attractive physical and mechanical properties, there is a need for improving the bond at the titanium/luting cement interface for the longevity of metal ceramic restorations.Purpose. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength (SBS) of resin-modified glass ionomer and resin cements to commercially pure titanium (CP Ti).Material and methods. Two hundred and forty CP Ti cast disks (9.0 x 3.0 mm) were divided into 8 surface treatment groups (n=30): 1) 50 mu m Al2O3 particles; 2) 120 mu m Al2O3 particles; 3) 250 mu m Al2O3 particles; 4) 50 mu m Al2O3 particles + silane (RelyX Ceramic Primer); 5) 120 mu m Al2O3 particles + silane; 6) 250 mu m Al2O3 particles + silane; 7) 30 mu m silica-modified Al2O3 particles (Cojet Sand) + silane; and 8) 120 mu m Al2O3 particles, followed by 110 mu m silica-modified Al2O3 particles (Rocatec). The luting cements 1) RelyX Luting 2; 2) RelyX ARC; or 3) RelyX U100 were applied to the treated CP Ti surfaces (n=10). Shear bond strength (SBS) was tested after thermal cycling (5000 cycles, 5 degrees C to 55 degrees C). Data were analyzed by 2-way analysis of variance (ANOVA) and the Tukey HSD post hoc test (alpha=.05). Failure mode was determined with a stereomicroscope (x20).Results. The surface treatments, cements, and their interaction significantly affected the SBS (P<.001). RelyX Luting 2 and RelyX U100 exhibited similar behavior for all surface treatments. For both cements, only the group abraded with 50 mu m Al2O3 particles had lower SBS than the other groups (P<.05). For RelyX ARC, regardless of silane application, abrasion with 50 mu m Al2O3 particles resulted in significantly lower SBS than abrasion with 120 mu m and 250 mu m particles, which exhibited statistically similar SBS values to each other. Rocatec + silane promoted the highest SBS for RelyX ARC. RelyX U100 presented the highest SBS mean values (P<.001). All groups showed a predominance of adhesive failure mode.Conclusions. The adhesive capability of RelyX Luting 2 and RelyX U100 on the SBS was decisive, while for RelyX ARC, mechanical and chemical factors were more influential. (J Prosthet Dent 2012;108:370-376)

Efficacy of Air-abrasion Technique and Additional Surface Treatment at Titanium/Resin Cement Interface

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

IMPROVEMENT TO THE MARGINAL COPING FIT of COMMERCIALLY PURE TITANIUM CAST IN PHOSPHATE-BONDED INVESTMENT BY USING A SIMPLE PATTERN COATING TECHNIQUE

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Titanium surface topography after brushing with fluoride and fluoride-free toothpaste simulating 10 years of use

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Fixation of autogenous bone grafts with ethyl-cyanoacrylate glue or titanium screws in the calvaria of rabbits

This study compared the fixation of autogenous onlay bone grafts with cyanoacrylate glue (Super Bonder) and with titanium screws. Twenty rabbits underwent bilateral parietal ostectomies. Bone segments were fixed anteriorly to the resulting bone defect. In group I, the grafts were fixed with 4 min long, 1.5 mm diameter screws; in group II, adhesive was used. The animals were killed after 5, 15, 30, 60 and 120 days. Histomorphometric analysis was used to quantify the maintenance of the graft area. Discrete areas of inflammatory reaction were seen in both groups after 5 days and for group II after 15 days. After 30 days, new bone formation was seen at the interface of the grafts. After 120 days, the graft was incorporated into the host bed in group I and partially incorporated in group II. There was a significant statistical difference regarding the mean graft areas between 15 and 120 days (p < 0.001) and between fixation methods (p < 0.002). Fixation with adhesive promoted a significantly greater area of bone graft than screw fixation, independent of time period. The adhesive was biocompatible, presented similar stability to the screw and maintained the bone area, although there was a delay in graft incorporation.

The Ability of Different Nickel-Titanium Rotary Instruments To Induce Dentinal Damage During Canal Preparation

The purpose of this study was to compare the incidence of dentinal defects (fractures and craze lines) after canal preparation with different nickel-titanium rotary files. Two hundred sixty mandibular premolars were selected. Forty teeth were left unprepared (n = 40). The other teeth were prepared either with manual Flexofiles (n = 20) or with different rotary files systems: ProTaper (Dentsply-Maillefer, Ballaigues, Switzerland), ProFile (Dentsply-Maillefer), SystemGT (Dentsply-Maillefer), or S-ApeX (FKG Dentaire, La Chaux-de-Fonds, Switzerland) (n = 50 each). Roots were then sectioned 3, 6, and 9 mm from the apex and observed under a microscope. The presence of dentinal defects was noted. There was a significant difference in the appearance of defects between the groups (p < 0.05). No defects were found in the unprepared roots and those prepared with hand files and S-ApeX. ProTaper, ProFile, and GT preparations resulted in dentinal defects in 16%, 8%, and 4% of teeth, respectively. Some endodontic preparation methods might damage the root and induce dentinal defects. (J Endod 2009;35:236-238)

Mechanical Strength and Analysis of Fracture of Titanium Joining Submitted to Laser and Tig Welding

This study compared the tensile strength and fracture mechanism of tungsten inert gas (TIG) welds in cylindrical rods of commercially pure titanium (cp Ti) with those of laser welds and intact samples. Thirty dumbbell-shaped samples were developed by using brass rods as patterns. The samples were invested in casings, subjected to thermal cycles, and positioned in a plasma arc welding machine under argon atmosphere and vacuum, and titanium was injected under vacuum/pressure. The samples were X-rayed to detect possible welding flaws and randomly assigned to three groups to test the tensile strength and the fracture mechanism: intact, laser welding, and TIG welding. The tensile test results were investigated using ANOVA, which indicated that the samples were statistically similar. The fracture analysis showed that the cpTi samples subjected to laser welding exhibited brittle fracture and those subjected to TIG welding exhibited mixed brittle/ductile fracture with a predominance of ductile fracture with the presence of microcavities and cleavage areas. Intact samples presented the characteristic straightening in the fracture areas, indicating the ductility of the material.

Photocatalytic Degradation of Phenol by Thermal Titanium Dioxide Thin Layer Electrodes

Electrochemical processes in industrial effluents have been studied as a means to obtain higher efficiency in wastewater treatment. Heterogeneous photocatalysis appears as a low-cost alternative through the use of lower wattage lamps and thermal TiO2 films. Photocatalysis became a clean process for water treatment due to hydroxyl radicals generated on semiconductor surface. Such radicals are able to degrade several organic compounds. This study used different electrodes and analytical methods for degradation of phenol molecules to reduce treatment costs, improve efficiency, and identify compounds formed during the decomposition of phenolic molecules. Thermal growth of TiO2 film was observed on the titanium electrode in rutile form. Application of an electrical potential on the Ti/TiO2 working electrode increases efficiency in reducing concentration of phenol after photocatalytic treatment. Still, high energy radiation (UVC) showed best degradation rates in photolytic process. Different compounds formed during the degradation of phenol were also identified in the UVC-PE treatment.