Betül Tuncelli

Shear bond strength of resin luting cement to glass-infiltrated porous aluminum oxide cores

STATEMENT OF PROBLEM Resin bonding surface treatment methods for conventional silica-based dental ceramics are not reliable for glass infiltrated high alumina content In-Ceram ceramics. PURPOSE This study developed an alternative surface treatment to improve resin bonding of glass-infiltrated aluminum oxide ceramic blasting with diamond particles and then observed the efficiency of this treatment. Material and methods. In-Ceram test specimens were prepared and divided into 2 groups. All specimens were sandblasted with Al(2)O(3), and blasted with diamond particles and 2 adhesive resins were applied. After bonding and storage in humid conditions, shear bond strength values were measured with a universal testing machine. Surface roughness and fracture interfaces were determined with a perthometer and a SEM. RESULTS The highest bond strength was obtained on the samples blasted with diamond particles (group II). The differences between the 2 groups and the 2 adhesive resin cements were both statistically significant. CONCLUSION Panavia-Ex cement exhibited higher bond strength than Super-Bond cement. This higher bond strength was attributed to ceramic oxide and ester bond and the mechanical properties of Panavia-Ex cement.

Evaluation of air-particle abrasion of Y-TZP with different particles using microstructural analysis

BACKGROUND This study evaluated the effect of air-particle abrasion with different particle sizes on the surface roughness and phase transformation of yttria-stabilized tetragonal zirconia ceramics (Y-TZP). METHODS Eighty-four Y-TZP discs of 15 mm diameter and 1.0 mm thickness were fabricated. The samples were divided into four groups (n = 21): (1) air-particle abrasion with 30 μm CoJet sand blast coating agent (CoJet, 3M ESPE); (2) 50 μm Al2O3 particles; (3) 110 μm Al2O3 particles; and (4) 250 μm Al2O3 particles. Each group was further divided into three subgroups each (n = 7) and treated for 5 seconds, 15 seconds and 30 seconds. Mean surface roughness was determined using a profilometer. The surfaces were analysed with a scanning electron microscope. XRD analysis was employed and the relative amount of the monoclinic phase was calculated. The results were statistically analysed by two-way analysis of variance (ANOVA, p < 0.05). RESULTS Air-particle abrasion with 250 μm Al2O3 particles for 30 seconds had the highest surface roughness (p < 0.001) and a significantly higher amount of monoclinic phase compared to air-particle abrasion with 30 μm, 50 μm and 110 μm particles (p < 0.001). CONCLUSIONS Duration and particle size of air-particle abrasion affects the roughness and phase transformation of Y-TZP. Longer treatment times with larger particles may result in degradation of material.

Influence of zirconia base and shade difference on polymerization efficiency of dual-cure resin cement.

PURPOSE The aim of this study was to investigate the polymerization efficiency of dual-cured resin cement beneath different shades of zirconia-based feldsphathic ceramic restorations. MATERIALS AND METHODS Five translucent zirconia (Zirkonzahn) discs (4.0-mm diameter, 1.2-mm height) were prepared. Feldsphathic ceramic (1.2 mm) (Noritake Cerabien Zr) in 5 shades (1M2, 2M2, 3M2, 4M2, 5M2) was applied on the zirconia discs. Twelve dual-cure resin cement specimens were prepared for each shade, using Panavia F 2.0 (Kuraray) in Teflon molds (4.0-mm diameter, 6.0-mm height), following the manufacturers instructions. Light activation was performed through the zirconia-based ceramic discs for 20 seconds, using a quartz tungsten halogen curing device (Hilux 200) with irradiance of 600 mW/cm(2) . Immediately following light curing, specimens were stored for 24 hours in dry, light-proof containers. Vickers hardness measurements were conducted using a microhardness tester with a 50-g load applied for 15 seconds. The indentations were made in the cross sectional area at four depths, and the mean values were recorded as Vickers hardness number (VHN). Results were statistically analyzed with one-way ANOVA and Tukey HSD test (p < 0.05). RESULTS A statistically significant decrease in VHN of the resin cement was noted with increasing depth and darkness of the shade (p < 0.05). CONCLUSION Curing efficiency of dual-cure resin cement is mainly influenced by the lightness of the shades selected.

Adhesion of 10-MDP containing resin cements to dentin with and without the etch-and-rinse technique

PURPOSE This study evaluated the adhesion of 10-MDP containing self-etch and self-adhesive resin cements to dentin with and without the use of etch-and-rinse technique. MATERIALS AND METHODS Human third molars (N=180) were randomly divided into 6 groups (n=30 per group). Conventional (Panavia F2.0, Kuraray-PAN) and self-adhesive resin cements (Clearfil SA, Kuraray-CSA) were bonded to dentin surfaces either after application of 3-step etch-and-rinse (35% H3PO4 + ED Primer) or two-step self-etch adhesive resin (Clearfil SE Bond). Specimens were subjected to shear bond strength test using the universal testing machine (0.5 mm/min). The failure types were analyzed using a stereomicroscope and quality of hybrid layer was observed under a scanning electron microscope. The data (MPa) were analyzed using two-way ANOVA and Tukeys tests (α=.05). RESULTS Overall, PAN adhesive cement showed significantly higher mean bond strength (12.5 ± 2.3 - 14.1 ± 2.4 MPa) than CSA cement (9.3 ± 1.4 - 13.9 ± 1.9 MPa) (P<.001). Adhesive failures were more frequent in CSA cement groups when used in conjunction with two-step self-adhesive (68%) or no adhesive at all (66%). Hybrid layer quality was inferior in CSA compared to PAN cement in all conditions. CONCLUSION In clinical situations where bonding to dentin substrate is crucial, both conventional and self-adhesive resin cements based on 10-MDP can benefit from etch-and-rinse technique to achieve better quality of adhesion in the early clinical period.

Surface deterioration of monolithic CAD/CAM restorative materials after artificial abrasive toothbrushing

PURPOSE The purpose of this in vitro study was to evaluate the effect of abrasive toothbrushing on the surface properties of monolithic computer-assisted design and computer-assisted manufacturing (CAD/CAM) materials stored in food-simulating liquids (FSLs). MATERIALS AND METHODS Fourty-eight disk-shaped test specimens of each material (Paradigm MZ100/PMZ, Lava Ultimate/LU, Vita Enamic/VE, and Vita Mark II/VMII) with a diameter of 10.0 mm and a thickness of 3.0 ± 0.05 mm were prepared. Specimens were divided into 4 subgroups (n=12) and stored in air, distilled water, 0.02 M citric acid, or 75% ethanol/water solution for 7 days at 36.5℃. Then, the specimens were brushed in a multi-station brushing machine under a vertical load of 2.0 N for 3 hours. Surface gloss (GU), roughness (Ra), and hardness (Vickers [VHN]) were measured after storage and brushing simulation. The data sets were statistically analyzed with 2 and 3-way ANOVAs followed by the Tukeys post-hoc comparisons (α=.05). RESULTS Statistically significant difference was found among the materials concerning the results of surface properties. VMII showed the highest VHN, while PMZ produced the lowest. Storage in FSLs significantly affected the VHN of PMZ and LU. VMII showed the lowest Ra and highest GU irrespective of FSLs and of abrasive toothbrushing. VE, LU, and PMZ produced significant decrease in GU and increase in Ra after toothbrushing. CONCLUSION Surface properties of monolithic CAD/CAM restorative materials were differently affected by the storage media and abrasive toothbrushing.

Influence of MDP Content in Different Resin Cements and Zirconia Primers on Ceramic-Resin Cement Bond Strength

ABS TRACT Objective: Evaluating the influence of MDP in different primers and resin cements on microtensile bond strength to zirconia ceramic after thermal cycling. Material and Methods: 6 zirconia blocks (23x20x10 mm) were prepared and divided into 3 groups (n=2) according to the following surface treatments: (1) air-particle abrasion with 50 μm Al2O3 particles, (2) air-particle abrasion and zirconia primer application, (3) air-particle abrasion and MDP-containing primer mixture application. Composite resin blocks were bonded to the pretreated zirconia surfaces using 2 different resin cements. Zirconia-composite blocks were cut to microbars with a cross-section of 1.0 ± 0.2 mm. The samples were thermocycled and microtensile bond strength tests were performed. Samples were evaluated under optical microscope. Data were analyzed with 1and 2-way ANOVA and Tukey multiple comparison tests (α=.05). Results: MDP based resin cements provided similar bond strengths (p>0.05) to air-particle particle abraded and primer pretreated zirconia surfaces. BisGMA based resin cements provided statistically higher bond strengths (p<0.05) to primer pretreated zirconia surfaces than air-particle particle abrasion alone. No statistically significant differences (p>0.05) were detected between the zirconia primers used. Conclusion: MDP containing resin cements or primers increase the bonding strength of zirconia. When using fixed partial dentures with zirconia substructures, clinicians are advised to use either primers or resin cements with MDP, if not both.

Occlusal Surface Reconstruction with Chairside Ceramic Onlay Using CEREC Biogeneric Design Mode: Case Report

The occlusal design of dental restorations should stay in harmonic relation to the remaining dentition. In CAD/CAM dentistry, the occlusion is generated by the CAD software based on standard morphologies from the dental database. An automated adaptation process of this standard morphology to an individual clinical situation is difficult and leading to manual adaptation of the proposal with design tools. The new biogeneric software of the chairside CAD/CAD system (CEREC) automatically collects optic measurement of the preparation side including mesial and distal neighbor teeth and antagonist teeth to design a restoration with a patient specific occlusal morphology. This clinical report demonstrated a case, which was treated with ceramic onlay designed and milled with CEREC system used in biogeneric design mode. Digital impression of the preparation was taken with the intraoral camera. Buccal scan,technique was used for taking the occlusal record. Preparation and antagonist images were automatically correlated by software and a virtual articulator was created. After trimming the virtual model, preparation margins were outlined with the automatic margin finder option of the software and then the insertion axis of the restoration was determined. The biogeneric restoration proposal was then automatically seated to the virtual model and desired changes were performed with the design tools of the software. The restoration was milled from feldspathic ceramic block.

YAŞLI BİREYLERİN DİŞ TEDAVİLERİ-DENTAL TREATMENT OF THE ELDERLY PATIENT

Ozet Demografik calismalar, bireylerin yasam surelerinin uzadigini ve toplam nufus oraninda yasli bireylerin arttigini gostermektedir. Yasli nufusun artmasi saglik bakim talebinin artmasini da gundeme getirmektedir. Bu nedenle, agiz dis sagligi acisindan daha fazla sayisida dogal disi bulunan yasli bireylere yonelik ozel yonetim ve becerileri kapsayan Gerodontoloji bilimi gelismek durumunda kalmistir. Cigneme etkinligi ve estetik gorunumun uzun yasam boyunca devamliliginin saglanmasi amaciyla alinmasi gereken onlemler ve gelismeler genel saglik durumlari ile birlikte degerlendirilmelidir. Anahtar sozcukler : Yasli bireyler, gerodontoloji, protetik tedavi. Abstract Demographic studies show that populations are living longer and the percentage of the elderly in these populations is increasing. There is evidence to show that as the population ages they make more demand upon medical and dental care. The speciality of gerodontology has evolved as a direct result in the increase of the percentage of the elderly in many populations and the special management of skills necessary to provide them with oral care. Prosthetic treatment provide to address masticatory efficiency and aesthetic relationships that can develop over a long lifetime with their general health conditions. Keywords :Elderly patient, gerodontology, prosthetic treatment.