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EGYPTIANDENTAL JOURNAL

Vol. 60, 3037:3048, July, 2014

* Lecturer of Fixed Prosthodontics, Misr University for Science and Technology (MUST)

Comparison between shear bond strengths after anodization and different methods of surfaCe

treatment of titanium bonded to dentin

Amal Abdallah Abdallah Abo-Elmagd*

ABSTRACTstatement of problem: The use of titanium has increased for metal ceramic restorations, post,

as well as for use in titanium implants. Surface treatments of titanium have been introduced to enhance the titanium bond strength with resin cement; however, a more reliable, easily used dental laboratory method has not been established.

objectives: The purpose of this in vitro study was to compare the effect of anodization and different methods of surface treatments of titanium alloyon the bond strength of a titanium bonded to dentin with resin based cement. Surface analysis of titanium at the interface was determined.

material and methods: A total of 75 uniform discs of titanium alloy (Titanium International (Medically pure alloy). (Ti-6Al - 4V) ELI, Carpenter.) were supplied as discs with 4mm diameter, 4mm thickness and 12.5 mm2 surface area. Discs were divided into 4 main groups (n=15) to receive different surface treatments: Group I: control group (TC), no treatment was performed. Group II: Sandblasting group (TS) was divided into two subgroups (TS1 and TS2) according to the particle size of Al2O3 powder. The titanium discs were grit-blasted using (50 and 250μm) grit-size of Al2O3 particles. Group III :( Plasma focus group TP). The samples were treated using nitrogen gas. Group IV: (Anodizing group TA). Treated discs were cemented and were tested for shear bond strength with the Instron machine. The type of bond failure was determined photographically records using stereo microscope with 20x for of. All of the data were presented as means and standard deviation (SD) values. ANOVA test was used to compare between means of the different groups. Tukey’s test was used in the procedure of pair-wise comparisons between the groups when ANOVA test is significant. The significance level was set at P ≤ 0.05. Statistical analysis was performed with SPSS 16.0® (Statistical Package for Scientific Studies) for Windows.

results: Statistical analysis (ANOVA) showed that Sandblasting (50 µm) TS1group showed the statistically significantly highest mean shear bond strength (24.1), this was followed by Anodizing group TA then Sandblasting (250 µm) TS2 group which showed values (17). There was statistically significant difference for Plasma Focus groups TP that showed much lower mean shear bond strength values (15.1). Control group TC showed the statistically significantly lowest mean shear bond strength (2.3).

Significance: Different surface treatments provided the greatest improvement in titanium alloys. All surface treated titanium alloy groups showed an increase in bond strength values when compared with non-surface treated titanium alloy groups .the unmodified titanium surface, may lead to an unsatisfactory titanium-resin cement bond.

Keywords: Shear bond strength, Surface treatments, Anodization, Sandblasting, Plasma focus, FTIR, resin cement

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introduCtion

Titanium alloys are receiving greatly attention for biomaterials because they have exceptional specific strength and corrosion resistance, light in weight, no cytotoxic and allergic troubles and the best biocompatibility among metallic biomaterials.

It was difficult to obtain high bond strength without surface modification. Surface treatments are common methods for improving the general adhesion properties of a material, by facilitating chemical and micromechanical retention between different constituents [1, 2]. Surface treatments are familiar methods for improving the adhesion properties of a material, by facilitating chemical and micromechanical retention between different materials. [3] However, titanium and titanium alloys are still not satisfactory for extended clinical application because In spite of the variety of solutions existing for engineering surface modifications of titanium, there is deficient in information about the use of solutions to encourage better bond strength values between cement and the metallic restoration. Hence the development of surface modification is a real essential [4].

In an attempt to improve the quantity and quality of the titanium alloy interface, surface treatments such as surface machining, acid etching, electropolishing, anodic oxidation, sandblasting or plasma-spraying may be undertaken to induce chemical modifications associated with alterations of the surface topography.[5] Sandblasting is used in industry to give surface roughening making materials more bondable. It is applied in ceramic and composite repair trials, indirect composite bonding, for pretreatment of metal surface in metal–ceramic restorations. Sandblasting is frequently used in adhesive dentistry, especially for pretreating acid-resistant materials. It can roughen the surface of a restoration, which is expected for micro-retention.[6]

Plasma-surface modification (PSM) as an new and successful materials processing technique is

widely used in the biomedical field. Titanium and its alloys are generally considered to be bioinert materials.

In order to improve the bioactivity, plasma spray and plasma based ion implantation technologies that can be classified under plasma surface modification can be used. The term ‘‘plasma’’ indicates a state of aggregation, in which positive and negative charges in equal concentration exist freely due to the ionization of atoms at high temperature. It is possible to change in the chemical composition and properties such as wettability, metal adhesion, refractive index, hardness, chemical inertness, lubricity, and biocompatibility of materials surfaces.[7-12]. anodization is a easy and successful method to modify the surface of titanium and its alloys for superior biocompatibility and bioactivity. The anodic oxide film exhibits a range of different properties that depend on the composition and microstructure of the materials and processing parameters, such as anode potential, electrolyte composition, temperature, and current. Anodic oxidation encompasses electrode reactions in combination with electric field driven metal and oxygen ion diffusion leading to the formation of an oxide film on the anode surface. Anodic oxidation is a well-established method to produce different types of protective oxide films on metals.[13] nowadays Resin cements are used for luting restorations with tooth structure for more retention and for enhanced resistance to failure. The bond strength of titanium is a very important factor in the cast restoration, it is similarly important to the bond strength of luting agent to dentin and must be within the range of clinical adequacy, Therefore careful attention should be directed towards the bond strength of titanium and dentin with the available luting dental cement ,as it may share in the main part of success of restoration . Furthermore, reaction in between the titanium and the resin cement when came in contact with tooth structure may be possible. Estimation of the probable link in between may reflect its effect on the bond strength. Hence studying the nature of

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the bond in between the titanium and resin cement worth to be considered as the success or failure of the super structure may depend totally on its bond strength with dentin.

materials and methods

75 uniform discs of titanium alloy (Ti – 6Al - 4V) (Titanium International (Medically pure alloy). ELI, Carpenter.) were supplied as discs with 4mm diameter, 4mm thickness and 12.5 mm2 surface area. Each titanium alloy disc was placed separately in clean glass flask containing distilled water to be washed for 30 minutes in an ultrasonic bath, to be sure the complete cleaning of the discs. All discs were dried at room temperature with air using air dryer. The prepared discs were divided randomly into 4 main groups according to the method of the surface treatment applied: Group I (15 discs of titanium alloy): control group (TC), no treatment was performed. Group II: Sandblasting group (TS) was divided into two subgroups (TS1 and TS2) (15 discs of titanium alloy for each one) according to the particle size of Al2O3 powder. (50 and 250μm). Group III (15 discs of titanium alloy): Plasma focus group (TP) using nitrogen gas. Group IV(15 discs of titanium alloy): Anodizing group (TA). For Group II: Special Copper holder was designed and constructed to fix the distance between the disc and the nozzle of the blasting machine. All discs were sandblasted at room temperature by high purity aluminum oxide (Al2O3), in sandblasting machine (Dental form -Torino Italy). Under standard conditions of pressure, time, and distance, using continuous constant motion of the blasting pressure (3 bar), time for (10 seconds), and at a fixed distance (10cm). The blasted discs were placed separately in glass flasks containing distilled water to be washed for 10 minutes in an ultrasonic bath, and then dried with air at room temperature, and became ready for cementation. Group III: Plasma focus group (TP). discs were introduced into the DPF chamber (UNU/ICTP, PPF plasma focus device of Mather type) and mounted axially above the anode with the help of

specially fabricated wooden holder to adjust the distance between the rim of the anode and the disc (2.5cm). Group IV: Anodizing group (TA): Special holder was designed and constructed to housing the titanium alloy disc during immersion in acidic solution. Just prior to anodization, each titanium sample (TA) was soaked in a specific acid solution mixture (150ml Hydrogen peroxide, 80ml nitric acid and 60ml hydrofluoric acid) for 3minutes, Titanium was then removed and rinsed with deionized water then was cleaned ultrasonically for 5 minutes. Next, the sample was used as an anode in an electrochemical cell, parallel to a platinum mesh acting as the cathode; the1M phosphoric acid and 1% hydrofloric acid solution served as an electrolyte solution with PH =5 . Then completed the circuit. A constant voltage of 20 V (Power supply DC, MUNK, PSP Vari plus, 25V /50 A) was then applied to the circuit for 30 minutes, with 100RPM stirring (Wise Stir feedback, dAIHAn Scientific, MSH-10, Ger). After the anodization process, the submerged samples were then placed in a solicitor for 10 minutes, rinsed and then soaked in deionized water for 2 minutes, and then dried in air at room temperature, and became ready for cementation.

75 recently extracted sound human molars were selected for the study, immersed in 4.5% solution of sodium hypochlorite for three minutes, washed three times in water, curetted to remove contaminating tissues and were stored in a jar containing artificial saliva solution was prepared, (Prepared in lab. of faculty of Pharmacy, Misr University for science and technology) according to Fusayama[14] for storage of natural teeth until time of experiments. 75 uniform rectangular buccally prepared teeth blocks (Chemically cured transparent resin

powder and liquid Acrostone -Acrostone dental factory. Industrial zone. Madinat Alsalam.) were prepared using a specially designed and constructed rectangular mold with 30 mm length, 15mm width, and 10 mm height. All teeth blocks were stored in a jar containing artificial saliva solution at room temperature.

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The treated and non-treated samples were cemented to human dentin with the resin cement (CEMENT-IT UNIVERSAL C&B resin) (Pentron Clinical Technologies, LLC 53 North Plains Industrial road Wallingford, CT 06492 U.S.A). the cemented disc and tooth block was placed in a specially designed and constructed rectangular guiding cementation device and immediately received a static cementing load of 1kg magnitude and maintained for 15 minutes, with specially constructed metal load device. The excess extruded cement was carefully removed from the sides of the bonded samples using a sharpened chisel. Bonded samples (Figure 1) were stored in 37oC artificial saliva solution for 24hr.

tests used after cementation

1- shear bond strength

The magnitudes of shear bond strengths were measured by a universal testing machine (Odel LRX-plus; Lloyd Instruments Ltd., Fareham, UK.). a special holder was designed and constructed . A circular interface shear test was designed to evaluate the bond strength. All samples were individually mounted onto a computer controlled materials testing machine with a load cell of 5 KN and data were recorded using computer software (Nexygen-MT-4.6; Lloyd Instruments). The load at failure was

divided by interfacial bonding area to express the bond strength in MPa: τ = P/ πr2

2- microscopical study of the debonded surfaces

The mode of bond failure at 20 x magnification for dentin surfaces and titanium alloy disc surfaces was determined. The two debonded interface of discs were examined using stereo microscope (Sz oLYMPUS Lg-PS2, Sz 40, Japan.). The results were recorded photographically.

3- scanning electron microscope examination

One representative titanium alloy disc after debonding was chosen from each group to be scanned at the interface using Environmental Scanning Electron Microscope QUANTA 200 in Antiquities Research Center, in Cairo, for interface examination and detection of mode of fracture of the samples after shear bond strength testing. The results were then tabulated and analyzed.

4- ftir analysis

IR analysis was made by Fourier transform in-frared spectro-photometer (FTIR-820, 1PC, Shi-madzu and Vetro 22 Bruker Germany) The grinding transparent disc of adhered disc /cement interaction were studied using thirty scans at a resolution of 8 cm and IR spectra of 350 to 4000cm-1. The results were recorded in spectra.

Fig. (1) a: Assembled guiding cementation device b: load device c: cemented titanium alloy disc.

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results

1-results of shear bond strength test

Statistically, data were presented as means and standard deviation (SD) values. ANOVA test was used to compare between means of anodized gr. and the different groups. Tukey’s test was used in the procedure of pair-wise comparisons between the groups when AnoVA test is significant. The significance level was set at P ≤ 0.05. Statistical analysis was performed with SPSS 16.0® (SPSS, Inc., Chicago, IL, USA.) (Statistical Package for Scientific Studies) for Windows

The load at failure was calculated from the following equation: τ = P/ πr2 Where; τ =shear bond strength (MPa) P =load at failure (n) π =3.14 r = radius of composite disc (mm)

The load-deflection curve was recorded using computer software (Nexygen-MT-4.6; Lloyd Instruments). Descriptive statistics, including the mean load at failure and standard deviation (SD) values of each group, are summarized in Table (1). The results revealed that: Sandblasting (50 µm) TS1group showed the statistically significantly

highest mean shear bond strength (24.1), this was followed by Anodizing group TA (19.6) then Sandblasting (250 µm) TS2 group (17). There was statistically significant difference for Plasma Focus groups TP that showed much lower mean shear bond strength values (15.1). Control group TC showed the statistically significantly lowest mean shear bond strength (2.3).

2- results of stereomicroscope analysis

Were recorded graphically (Figure 2) for the two debonded surfaces of the all groups of titanium alloy samples with the luting cement used at 20 x magnifications. Stereo microscope images revealed that all samples had adhesive cohesive failures, and the only difference was in the shape of failure and the amount of the remaining cement adhered to the disc surface, except the control group image revealed that the failures was adhesive in nature, while control group had more shiny appearance, clear surface gloss was observed in the image of titanium alloy treated by plasma focus .

3- scanning electron microscope (sem) analysis

SEM images of the interfacial area of the

*: Significant at P ≤ 0.05, Means with different letters are statistically significantly different according to Tukey’s test

TABLE (1): Means, standard deviation (SD) values and results of ANOVA test for comparison between shear bond strength in the all groups and Bar chart representing mean and SD values of shear bond strength in the all groups.

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tested specimens (Figure 3). Showed the unique characteristics of the reaction zone of each disc group. The crack in all groups was located at the interfacial area and more likely to be in the resin cement. All images showed different features within the interfacial area according to the different kinds of surface treatment applied. There was no clear reaction zone in all these surfaces, only a band of the bonder that filled up the rough surface of the titanium that can be seen. The thin gray layer between titanium and resin cement may be an oxide layer. The unique characteristic found in this system was the bright white patches, which were clusters of silica particles of resin cement,lying along the interface. all discs had adhesive cohesive failures, and the only difference was in the shape of failure and the amount of the remaining cement adhered to the surface

4- ft-ir analysis

Analysis of FT-IR spectra of titanium alloy samples before and after surface treatment were made and presented graphically in Figures (4-6) Spectroscopic analysis by FT-IR showed that absorption in the 400-4000 cm_1 range changed with each group. The shifting of bands and change in their intensity indicates chemical reaction.

The IR spectrum of resin cement is shown in Figure (4). The structure of resin cement used was confirmed by the following absorption bands: a broad band at 3538 cm-1 and a strong absorption in the region of 3315 cm-1 are attributed to υ oH non-bonded and bonded group respectively. The presence of bands at 2958 cm-1 and 2928 cm-1 are due to υ CH stretching groups. A very strong absorption band at

Fig. (2) The two debonded surfaces of the all groups of titanium alloy samples with the luting cement at 20 x.

Fig. (3) SE photomicrograph of interface at 1000 x.

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1721cm-1 is due to υ C=o (keton). Absorption band at 1638 cm-1 is due to υ C=C. Absorption band at 1510cm-1 can be attributed to amine salt R3N.HCl. Absorption band at 1452 cm-1 is due to υ CH bending . Absorption band at 1401 cm-1 is attributed to PO4

--- phosphate. The presence of bands at 1075, 1165 and 1268 cm-1 are due to υ o-C group ether linkage Absorption band at 1045cm-1 is attributed to υ oH bending. bands at 467 and 671 cm-1 are due to some additives. (TC group) with resin cement, the reduced mass effect υo-H is less than resin itself (3291 cm-1and 3315 cm-1) this indication for interaction of OH with metal via chemical bond M - O - H (M chelation with OH) .Also the intensity of υ C=o at 1721 cm-1 of resin cement is more than the alloy, this also may be an indication for chemical bonding.

IR spectra of titanium alloy treated by sandblasting showed nearly the same main components with variation in the number of bands and its intensity. Shallow basin peak at 3437 cm-1 instead of two bands at 3315 cm-1 and 3538 cm-1 in case of resin cement and disappearance of shoulder band at 1165 cm-1 were found in case of alloy treated by sandblasting 50 (this is due to sand considered as impurities). By comparing the two IR spectra of titanium alloy treated by sandblast TS1 and TS2, the

intensity of the bands with TS1 is more than TS2. This seems to be logic since because the surface area of TS1 is more than surface area of TS2 and consequently the adsorption with TS1 is large.

IR spectra of anodizing groupTA revealed that shallow basin peak appeared at 3425 cm-1 instead of two bands at 3315 cm-1 and 3538 cm-1 in case of resin cement due to formation of Si / O , new Absorption band at 1645cm-1 appeared and disappearance of bands at 1295 cm-1and 1244 cm-1.etching process increases surface area of alloy, this appears from shape and intensity of bands by comparing alloy without etching.

In case of TP group, IR spectra revealed that shallow basin peak appeared at 3435 cm-1 instead of two bands at 3315 cm-1 and 3538 cm-1 in case of resin cement due to formation of I-N and the probability for formation of H- bond. The high intensity of the bands at 3435 cm-1is indication for Si-OH and Si –O—H—N—Ti due to formation of Ti N. In addition, the intensity of other bands is increased, i.e. roughness is increased via plasma treatment. And increase the actual area for adsorption. This appears from shape and intensity of bands by comparing alloy without etching.

Fig. (4) FTIR of resin cement and FTIR of interface of TC and resin cement.

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disCussion

The establishment of strong and durable cement/titanium bond depends on the composition, properties and adhesive ability of the used cement in one hand and on titanium surface properties in the other hand. In addition to the effect of the variation in surface chemistry of titanium, according to surface treatment applied, on their bond strength to the luting cements, the effect of the variation in surface microtopography should also be considered. Many researchers pointed out the importance of micromechanical interlocking on the bonding of luting cements to metallic substrates such as titanium.[15, 16, 17]

The resin/metal interface has been an area of concern for clinicians because of poor chemical bonding of resin composites to cast metals. Most debonding in resin-cemented prostheses is due to failure at the resin/metal interface. It was difficult to obtain high bond strength without surface preparation. There are several methods available for bonding resin to cast dental prostheses. Surface treatments are common methods for improving the general adhesion properties of a material, by facilitating chemical and micromechanical retention between different constituents. Therefore, in the current study one type of titanium alloy with four different categories of surface treatment of titanium alloy and one type of resin cement were used.

Fig. (5) a- FTIR of interface of TS1 and resin cement and b-FTIR of interface of TS2 and resin cement

Fig. (6) a- FTIR of interface of TP and resin cement and :b- FTIR of interface of TA and resin cement

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Bond strength refers to the force required to separate two parts and it consists of two factors: chemical adhesion and mechanical bonding. Mechanical bonding is an anchoring effect that is related to the surface roughness of the alloy surface. Surface treatment of the metal by sandblasting with Al2O3 particles has enhanced the surface area of the metal, increased the energy of alloy surfaces, and also increased the composite resin –metal bond strengths. Therefore, the mechanical and chemical factors for bonding are necessary in creating a stable bond. [18-20]

It was difficult to obtain high bond strength without surface modification. Surface treatments are common methods for improving the general adhesion properties of a material, by facilitating chemical and micromechanical retention between different constituents. [1] Therefore, in the current study one type of titanium alloy with 4 different categories of surface treatment of titanium alloy and one type of resin cement were used.

This study indicates that an unmodified titanium surface, may lead to an unsatisfactory titanium-resin cement bond. This is in agreement with previous studies. Wang and Fung have indicated that the unmodified titanium surface produces a weak, porous, nonprotective and nonadherent oxide layer that is unsuitable for porcelain bonding. As seen in the photomicrograph, the titanium specimen shows some areas with remnants of resin cement. [21]

During the present research work, we used four groups (sandblasting group, Anodizing group, Plasma group and control group) to create a new titanium surface combining all the aforementioned surface texture features. In this study titanium alloy without surface treatment is taken as a control group. The present study showed that precise method selection and the sequence of processing played the main role in preparation of the rough titanium surface.

Adhesive resin cements are used not only to prevent the dislodgement restorations, but also

to obtain a strong and long-lasting cementation between tooth and restoration. Thus, it is very important to select the best combination of resin cement and surface treatment for durability.[22]

According to Tjan et al (1980) [23] and Taira el al (2000)[24], the durability of bond strength depends on factors such as bonding of the interface between resin cement and metal, physical properties of the cement and linear thermal expansion coefficient of the cement and metal.[25]

The CEMENT-IT UNIVERSAL C&B resin cementation system is a Bis-GMA based composite resin and was developed to bond with all indirect restorative materials (polymers, metals or ceramics). In this study, when compare between means values of shear bond strengths of different groups it was found that anodization as a surface treatment of titanium alloy gave the high level of shear bond strength with resin adhesive cement but not the highest, titanium group treated with sandblasting 50µm gave the highest value. The CEMENT-IT UNIVERSAL C&B resin cementation system composite resin showed mean bond strength of 24.10 MPa after sandblasting (TS1) , mean bond strength of 19.6 MPa after anodized (TA)and 17.00 MPa after sandblasting (TS2). mean bond strength 15.1 MPa after plasma (TP) These values were statistically significantly different, which means the oxide layer removal and new formation have effect on the composite resins’ shear bond strength to titanium, although the higher numeric difference was seen at (TS1). The self-limiting characteristic of superficial oxide layer formation on titanium surface might have been responsible for the results of statistical equality among the tested groups. Mean bond strength of TC gr was 2.3 MPa.

SEM observations of the bonded specimens confirmed good integrities between titanium alloy and resin cement. This may be attributed to the low viscosity of the resin cement used in this study, which can wet the surface of titanium alloy effectively, and the bond strength values, which did

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not appear to reflect the adaptation of the interface completely. Some recent studies also reported that flowable resin cement had a good adapting ability to surfaces. According to the C-factor theory, there would be more chance for relaxation of shrinkage stress caused by polymerization. It may be another possible reason for no gaps or bubbles at the bonding interface.[26,27]

In certainty, grit blasting is the most common method for surface preparation of titanium. However, bond durability is poor for grit blasted adherents. Durable surface preparation can be achieved by forming oxides in anodizing and/or etching solutions. Typically anodization results in the best bond durability for titanium alloys, primarily because of the microrough surface morphology that results from the treatment. Atypical acid etching preparation which is used. There are three distinct disadvantages to the acid etch and anodizing procedures. They are: (1) that they require extremely hazardous materials; (b) that they are difficult to apply to parts which cannot be immersed in a bath due to large surface area or curved surfaces; and (3) that they represent a threat to adjacent component parts of other materials. [1, 28,29, 30]

From stereomicroscope images and SE photomicrograph, it was found that, the shape fracture difference seems to be linked to the most wetting ability of resin cement, due to MDP, resulting in the best contact area between the cement and titanium surface. Another reason for cement cohesive predominant fracture pattern is its high adhesion capacity that exceeds its own cohesive strength. [28, 31]

Chemical analysis was made for all groups and the resulting component at interface using FTIR analysis. IR analysis is considered a technique, which gives information about bond and composition of the material used. It is sensitive, accurate method with the least amount of material used in analysis[32,33].

A Fourier transform infrared spectrophotometer is a more reliable method for molecular structure to determine the chemical composition of the interface of the titanium alloy and luting cement in order to study interface between them. FTIR was utilized at a resolution of 8 cm_1 by taking 30 scans and IR spectra of 350 to 4000cm-1. The results were recorded in spectra. Any shifting of the band in such spectra compared with that of the cement mix indicates presence of reaction. Interpretation of chart of FTIR revealed that chemical reaction occurred between resin cement and titanium alloy, and this was reflected on the bond strength between the alloy and the luting cement.

Analysis of cement is a must to identify the reactions that occur in their mixes as well as at the interface. Differences in the cement mixes spectra explain their different reaction with different surface treatment and the resulting shear bond strengths. Always spectra of cement metal interface showed increase in inorganic bands in comparison of the same identical type of cement which reflects high mechanical properties of materials.

Considering the analysis of interfaces of TS, TA as well as TP groups showed high increase in the intensities of the band compared with TC group. This is confirmed by high bond strength in TS, TA as well as TP groups.

In TS interface analysis, showed nearly the same main components with variation in the number of bands and its intensity. The presence of band shift with shallow basin peak at 3437 cm-1 instead of two bands at 3315 cm-1 and 3538 cm-1, indicates chemical reaction so reactivity increases due to sand considered as impurities. By comparing the two IR spectra of TS1 and TS2, the intensity of the bands with TS1 is more than TS2, this seems to be logic since because the surface area of TS1 is more than surface area of TS2 and consequently the adsorption with TS1 is large. This was approved by increases of mean value of bond strength of TS1 when compared with value of T2.

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In case of TP group, The IR spectrum revealed that strong intensity of the bands at 3435 cm-1is indication for Si-OH and Si –O—H—N—Ti due to formation of Ti N. Also the intensity of other bands is increased, i.e. roughnesses are increased via plasma treatment and increase the actual area for adsorption. This appears from shape and intensity of bands by comparing alloy without treatment and was approved from the increased mean bond strength value.

ConClusions

Based on the previous results and according to the circumstances of this research work the follow-ing conclusions could be obtained:

The unmodified titanium surface, gave an unsatisfactory titanium-resin cement bond and using anodization as a surface treatment of titanium alloy gave the high level of shear bond strength with resin adhesive cement but not the highest, titanium group treated with sandblasting 50µm gave the highest.

Lastly Interpretation of chart of FTIR revealed that chemical reaction occurred between resin ce-ment and titanium alloy, and this was reflected on the bond strength between the alloy and the luting cement.

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