Çağrı Ural

The Effect of Laser Treatment on Bonding Between Zirconia Ceramic Surface and Resin Cement

Abstract Objective. The purpose of this in-vitro study was to evaluate and compare the effects of different surface treatments and laser irradiation on the shear bond strength of resin cement to zirconia-based ceramic. Material and methods. Forty zirconia core specimens (10-mm diameter, 2-mm thickness) were produced and embedded in the centers of autopolymerizing acrylic resin blocks. Subsequently, specimens were randomly divided into four groups, each containing 10 specimens, for different surface treatment methods. The details of the groups are as follows: Group C, no treatment applied (control); Group SB, bonding surfaces of ceramic disks were airborne particle-abraded with 110-μm alumina oxide particles; Group HF, bonding surfaces of ceramic disks were etched with 9.6% hydrofluoric acid; and Group L, bonding surfaces of ceramic disks were irradiated by a CO2 laser. A total of 40 composite resin disks were fabricated and cemented with an adhesive resin cement to the specimen surfaces. A universal test machine was used for the shear bond strength test at a crosshead speed of 1 mm/min. Results. The highest shear bond strength values were obtained with Group L (20.99 ± 3.77 MPa) and the lowest values with Group C (13.39 ± 3.10 MPa). Although there was no significant difference between Groups C, HF and SB (P > 0.05), Group L showed a significant difference from all other groups (p < 0.05). Conclusion. All surface treatment methods improved the bond strength between resin cement and the zirconium oxide ceramic surface. CO2 laser etching may represent an effective method for conditioning zirconia surfaces, enhancing micromechanical retention and improving the bond strength of resin cement on zirconia ceramic.

Determination of Resin Bond Strength to Zirconia Ceramic Surface Using Different Primers

Abstract Objective. To evaluate the effect of different primers on the bond strength of adhesive resin cement to zirconia ceramic surface in vitro. Material and methods. Thirty zirconia disk-shaped ceramic specimens (10×2 mm2) were divided into three equal groups for the application of different primers: Monobons-S, Clearfil Ceramic Primer and Signum Zirconia Bond. A further 10 specimens served as a control group. Forty composite resin blocks (6×2 mm2) were cemented (Panavia F 2.0) to zirconia ceramic specimens. Shear bond strengths were measured. Treated zirconia ceramic surfaces were examined using scanning electron microscopy. Results. One-way ANOVA showed that the application of different primers affected the shear bond strength of adhesive resin cement to zirconia ceramic. The highest test values were obtained with application of Signum Zirconia Bond, and the lowest values were obtained in the control group. Conclusion. Signum Zirconia Bond is effective for increasing the bond strength of adhesive resin cement to zirconia ceramic.

Effect of air abrasion particles on the bond strength of adhesive resin cement to zirconia core

Abstract Objective. To evaluate the effect of air abrasion with different particles of different sizes and forms on the shear bond strength of adhesive resin cement to zirconia core. Material and methods. Sixty zirconia core disks were produced and sintered. The specimens were divided into six equal groups for application of air abrasion procedures. The surfaces of the specimens were treated with one of five air abrasion particles: 30 μm silica-coated aluminum oxide particles; 1–3 μm synthetic diamond particles; 110 μm aluminum oxide particles; 30–50 μm synthetic diamond particles; and 60–80 μm cubic boron nitride particles. The remaining 10 specimens were untreated and served as controls. Composite resin disks were cemented to each of the zirconia core specimens. All specimens were stored in distilled water at 37°C for 24 h and thermocycled for 6000 cycles. The shear bond strength was measured using a universal testing machine at a crosshead speed of 1 mm/min. Data were statistically analyzed by one-way ANOVA with Tamhane tests (α = 0.05). The effect of the air abrasion procedures was examined using scanning electron microscopy. Results. Air abrasion with different materials affected the bond strength (P < 0.001). The highest bond strengths were obtained by air abrasion with 30–50 μm synthetic diamond particles; the lowest bond strengths were obtained in the control group (P < 0.001). Conclusion. Air abrasion with 30–50 μm synthetic diamond particles, 60–80 μm cubic boron nitride particles and 110 μm aluminum oxide particles showed higher bond strength values than other methods.

The effect of different surface treatments on cement-retained implant-supported restorations.

The purpose of this study was to evaluate the effects of the various surface treatment methods on the retention of single crowns on implant abutments. The study included 50 single crowns that were cemented with adhesive resin cement onto the ITI solid abutments. The specimens were randomly divided into 5 groups, each including 10 specimens according to the following surface treatments: group C, control, abutments remained unaltered as control; group L, etching with CO(2) laser; group SB, sandblasting with 50-μm Al(2)O(3); group MS: coating with titanium nitride (TiAlN) with a radiofrequency magnetron sputtering system; and group SP, silicoating by Silano-Pen. After the surface treatment procedures were finished, the casted crowns were cemented onto the abutments, and thermocycling was applied to simulate oral environment. The uniaxial tensile force was applied to all test crowns using a universal test machine (Instron) with a crosshead speed of 0.5 mm/min. The load required to dislodge each crown was recorded in Newton. The lowest tensile bond strength values were obtained with group MS (223.26 ± 14.30 N) and significantly differ from all other groups except group C. Group SB showed highest test results (506.02 ± 18.04 N) and differs from other groups (P < .05). The test values that were obtained in group MS-group C did not show significant differences (P > .05). Sandblasting is an effective method to increase bond strength. Also, Silano-Pen and laser application is advisable for increasing the crown retention to abutments. Titanium aluminum nitride coating with magnetron sputtering technique seems to be ineffective.

The Effect of Screw Color and Technique to Fill Access Hole on the Final Color of Screw-Retained Implant Crowns

The purpose of this study was to investigate the effect of screw color and thickness of the composite on the final implant color. Gray and golden-colored titanium specimens were used as 2 different backgrounds. Composite disks were made in different thicknesses. Titanium and composite disk samples were placed into a metal mold as in the test groups for color measurement. The background color did not affect the final color. Composite resin thickness affected the final color.

Investigation of the effect of titanium alloy surface coating with different techniques on titanium-porcelain bonding.

STATEMENT OF PROBLEM The bond strength of dental porcelain to titanium is inadequate as a clinical alternative to conventional alloys for metal ceramic restorations. PURPOSE The purpose of this in vitro study was to evaluate the effects of coating titanium surface with a micro-arc oxidation (MAO) technique and hydroxyapatite (HA) on the bond strength of porcelain to titanium surfaces. MATERIAL AND METHODS One hundred twenty machined titanium specimens with a dimension of 25×3×0.5 mm were prepared from grade 5 titanium as the metal substrate. Specimens were divided into 6 groups (n=20) according to the surface treatment used: airborne-particle abraded (control), coated with MAO for 5 minutes, coated with MAO for 15 minutes, coated with MAO for 30 minutes, coated with HA, and combination of MAO and HA. Each group was further divided into 2 subgroups (n=10) according to the type of porcelain used: Noritake Ti-22 porcelain or Vita-Titankeramik porcelain. The bond strength was tested with a universal testing machine at a crosshead speed of 0.5 mm/min. Data were analyzed statistically with 2-way ANOVA and Tukey honest significant differences multiple comparison tests (α=.05). RESULTS For both porcelain groups, the 30-minute MAO groups showed higher bond strength values than those of the control groups (P<.05). In the Vita Titankeramik porcelain subgroup, the specimens coated with HA did not show any statistical differences compared with those of the control group (P>.05). Surface roughness was affected significantly (P<.001) by the coating procedure compared to that of the the control group. CONCLUSIONS Coating with either MAO or HA improved titanium-porcelain adhesion.

The effect of amine-free initiator system and the polymerization type on color stability of resin cements

We investigated the short-term (4 weeks) color stability of light-cure and dual-cure resin cements. Sixty disk-shaped test specimens of adhesive resin cement (10 × 1 mm) were prepared. One feldspathic porcelain test specimen (12 × 14 × 0.8 mm) was prepared from a prefabricated ceramic block. The feldspathic sample was placed on the resin cement disk and all the measurements were performed without cementation. Specific color coordinate differences (ΔL, Δa, and Δb), and the total color differences (ΔE) were calculated after immersion in distilled water for different periods. Data were compared using one-way analysis of variance (ANOVA) (α = 0.05). The test results revealed that different chemical structures and curing modes affected the ΔE values (P < 0.05). The highest ΔE values were obtained for RelyX Unicem dual-cure cement (2.14 ± 0.40), and the lowest for NX3 light-cure cement (0.78 ± 0.34). Third generation adhesive resin cement free of tertiary amines and benzoyl peroxide showed relatively slight color change in both test groups (light-cure and dual-cure resin cement). (J Oral Sci 58, 157-161, 2016).

Effect of pre‐processing methods on bond strength between acrylic resin teeth and acrylic denture base resin

OBJECTIVES This study evaluated the effects of various pre-processing methods on the bond strength between resin and denture teeth. BACKGROUNDS Debonding of acrylic resin teeth from denture base material is a problem for patients wearing complete dentures. MATERIALS AND METHODS Four experimental groups (n = 30) were investigated by subjecting tooth-resin bonding to tensile loading. Specimens were prepared and tested according to the methods of the International Standards Organization (ISO 22112:2005) using a special assembly. Four pre-processing surface treatments of teeth were applied: (i) ST(1), no treatment applied (control); (ii) ST(2) , wax solvent (Dewaks, Faber Kimya & Ilaç, Turkey); (iii) ST(3), boiling water followed by conditioning with methyl methacrylate (MMA) monomer (Meliodent, Bayer Dental, Germany); (iv) ST(4), boiling water followed by wax solvent agent and finally MMA monomer application. Bond strength test was performed using a universal testing machine. RESULTS All the strength values of the test groups were within clinically acceptable limits. The lowest values were from the ST(1) group and the highest values were in the ST(4) group. CONCLUSIONS Wax elimination methods affected bonding strength. Application of wax solvent and MMA monomer to the ridge lap surfaces of the teeth gave the best results. In clinical practice, this application procedure may decrease the bonding failure of denture teeth.

Color match of a feldspathic ceramic CAD-CAM material for ultrathin laminate veneers as a function of substrate shade, restoration color, and thickness

Statement of problem. The final color of a ceramic restoration, especially an ultrathin veneer, is important, but selecting the correct shade is difficult because the substrate can affect the final color of the restoration. Purpose. The purpose of this in vitro study was to investigate the effect of substrate shade and thickness on the final color of ultrathin laminate veneers milled from feldspathic ceramic and to present a straightforward methodology with which a clinician can visualize the effects of substrate color, ceramic thickness, and prefabricated computer‐aided design and computer‐aided manufacturing (CAD‐CAM) block color on the final color of the restoration. Material and methods. All specimens were fabricated by slicing CAD‐CAM feldspathic ceramic material with a precision cutter into 12×10‐mm slices of approximately 0.35, 0.55, 0.75, and 1.55 mm in thickness with 10 different colors (0M1‐1M1‐1M2‐2M1‐2M2‐2M3‐3M1‐3M2‐3M3‐4M1). As a background substrate, composite resin disks (12×10×2 mm) were fabricated with different shades (0M1 S, 1M1 S, 2M3 S, 3M2 S, 4M3 S, 5M3 S). The CIELab values of the polished surfaces of each specimen were measured on a background (white or simulated foundation) with a spectrophotometer by a single experienced operator, and color differences (&Dgr;E) were calculated. Mean ±SD values were calculated and subjected to ANOVA with 2 variables (substrate and ceramic color) (&agr;=.05). Results. Combinations of a lighter substrate shade and a lighter value ceramic restoration and of a darker substrate shade and darker value ceramic restoration only changed the final color of the restoration minimally. Conclusions. The final color of a dental restoration is affected by the thickness of the restoration, the substrate color, and the ceramic color. Lighter and darker substrate colors show more color changes, and thin veneers cannot mask the substrate color.

Determining the localization of premolar zenith positions according to the gingival line

BACKGROUND The gingival zenith (GZ) positions according to a reference line in the premolar (PM) area remain concern, especially for the clinicians in placing the gingival contours during surgery. OBJECTIVES The objectives of this study are to determine the maxillary PM GZ positions according to GZ line (GZL). MATERIALS AND METHODS A sample population of 63 patients with healthy gingival tissue was studied. The GZ was determined at the most apical point of the gingival marginal scallop. A horizontal-zenith line (ZL) was drawn connecting the GZ from the ipsilateral canine (C) and central incisor teeth. Reference lines were drawn, and bilateral measurements were taken in the respective stone casts in the PM area. RESULTS No statistically significant differences were found between bilateral first premolars (FPM) and second premolars (SPM). When considering ipsilateral FPM and SPM, statistically significant differences were found between them. For all PM teeth, the mean distance value of GZ to GZL was approximately 1.32 mm. CONCLUSIONS The present study results showed that GZs of FPM and SPM teeth for both left and right sight was coronally located according to ZL.