Evşen Tamam

Do surface treatments affect the optical properties of ceramic veneers

STATEMENT OF PROBLEM Surface treatments may affect the optical properties of ceramic veneers before cementation. PURPOSE The purpose of this study was to evaluate whether various surface treatments affect the optical properties of different types of ceramic veneers. MATERIAL AND METHODS Disk-shaped ceramic veneers (N=280) were prepared from the IPS e.max Press, e.max CAD, Empress Esthetic, e.max Ceram, and Inline ceramic systems with 0.5-mm and 1.0-mm thicknesses. The ceramics were divided into 4 groups: no surface treatments; etched with hydrofluoric acid; airborne-particle abraded with 30-μm Al2O3; and irradiated with erbium:yttrium-aluminum-garnet laser. A translucent shade of resin was chosen for cementation. Color parameters were examined with a colorimeter. Statistical analyses were done with 3-way ANOVA and the Bonferroni test (P=.05). RESULTS Significant interactions were noted between the surface treatments, ceramic type, and thickness for ΔE values (P=.01), and no significant interactions were noted for L* (P=.773), a* (P=.984), and b* (P=.998). The greatest color change occurred after airborne-particle abrasion with 0.5-mm-thick e.max Press (2.9 ΔE). Significant differences in ΔE values were found among the hydrofluoric acid, airborne-particle abrasion, and laser groups for 0.5-mm-thick ceramics, except IPS Inline, and among the hydrofluoric acid, airborne-particle abrasion, and laser groups for 1.0-mm-thick ceramics, except Empress Esthetic ceramics. CONCLUSIONS The color change of the ceramics increased after the surface treatments, particularly as the ceramics became thinner.

Prosthetic rehabilitation of hypophosphatasia: a case report

Hypophosphatasia is a congenital disease characterized by deficiency of serum and tissue non-specific alkaline phosphatase activity. The disease occurs due to mutations in the liver/bone/kidney alkaline phosphatase gene. Six clinical forms of hypophosphatasia are recognized. Systemic symptoms of the disease are respiratory complications, premature craniosynostosis, widespread demineralization and rachitic changes in the metaphases, stress fractures, chondrocalcinosis and osteoarthropathy. Characteristic dental symptoms are premature deciduous teeth loss, premature exfoliation of fully rooted primary teeth, severe dental caries and alveolar bone loss. This clinical report describes the prosthetic rehabilitation of a twenty two year-old Turkish female patient with hypophosphatasia.

ÖN BÖLGE İMPLANTLARININ HASTA BAŞI CAD-CAM KİŞİSEL SERAMİK ABUTMENTLARLA REHABİLİTASYONU: 2 OLGU SUNUMU

Kisisel abutmentlar, anterior bolgeye uygulanan implant destekli protezlerde karsilasilacak bir cok problem cozmeye yardimci olur. Kisisel abutmentlarin uretiminde kullanilan tekniklerden biri de; zirkonya ve lityum disilikat abutmentlarin uretimine olanak saglayan CAD-CAM teknolojisinin kullanilmasidir. Bu vaka raporunda; anterior bolgede yetersiz mezio-distal genisligi bulunan 2 vakanin CAD-CAM teknolojisi ile tasarlanan kisisel seramik abutmentlar ile tedavisi anlatilmaktadir. Her iki vakada da sol maksiller santral dis bolgesine yerlestirilen implant, CAD-CAM sisteminde tasarlanan ve uretilen kisisel abutmentlar ile restore edilmistir. Abutmentlar, Vaka 1 icin zirkonyadan ve Vaka 2 icin lityum disilikattan uretilmistir. Daha sonra abutmentlarin uzerine lityum disilikat kronlar yapilmistir. 12 aylik takibin sonunda; her iki hasta da protezlerinden memnun olduklarini belitmislerdir. 5 ay sonunda Vaka 2’de abutment vida gevsemesi goruldu fakat 12ay suresince baska bir komplikasyon gorulmedi.

The Effect of Porcelain Firing on Electrochemical Behavior of a Dental Alloy in Hydrogen Peroxide.

PURPOSE The aim of this study was to evaluate changes in electrochemical corrosion properties of porcelain firing simulated nickel-chromium dental casting alloy exposed to a 10% hydrogen peroxide bleaching agent. MATERIALS AND METHODS The electrochemical corrosion behavior of a Ni-Cr alloy was evaluated by cyclic polarization test in the aerated electrolyte (pH = 6.5). Test groups were produced in as-cast (group 1, control group) and simulated porcelain firing (group 2: heat-treated/mean value; group 3: heat-treated/cycle) conditions. Scanning electron microscopy (SEM) was also used to examine the alloy surfaces before and after the corrosion test. RESULTS The ranking of the groups with respect to Ecorr and Icorr was as follows: 1, 2, 3 and 3, 1, 2, respectively. Group 3 exhibited the greatest and group 2 displayed the least corrosion tendencies. An increase in corrosion rates was observed after heat treatment/cycle state. Post-corrosion SEM photographs were also consistent with the test results. CONCLUSION Within the parameters of this study, a single heat treatment is insufficient to cause upheaval in corrosion behavior of a Ni-Cr alloy subjected to 10% hydrogen peroxide.

Electrochemical Corrosion and Surface Analyses of a Ni‐Cr Alloy in Bleaching Agents

PURPOSE The aim of this study was to evaluate the corrosion behavior of a Ni-Cr dental casting alloy subjected to 10% hydrogen peroxide (HP) and 10% carbamide peroxide (CP) bleaching solutions and to determine the composition of the surface oxide layer formed on the alloy specimens. MATERIALS AND METHODS Ten cylindrical specimens (4 mm in diameter × 25 mm in height) were cast from a Ni-Cr alloy (Wiron 99) and divided into two groups (n = 5). A potentiodynamic polarization test was used to compare the corrosion rates of specimens in HP and CP (pH = 6.5). Before cyclic polarization tests, all alloy specimens were allowed to reach a steady open circuit potential (Ecorr ) for a period of 1 hour. Then tests were initiated at 100 mV versus standard calomel electrode (SCE) below Ecorr and scanned at a rate of 1 mV/s in the anodic direction until reaching 1000 mV over the Ecorr value. The scan then was reversed back to the Ecorr of the specimens. The open circuit potentials (Ecorr ) and the current densities (Icorr ) were determined using the anodic Tafel regions extrapolating from the curves. Differences in Ecorr and Icorr were determined using one-way ANOVA (α = 0.05). In addition, corrosion rates were calculated from these curves. Before and after polarization tests, a scanning electron microscope (SEM) examination accompanied by energy dispersive X-ray spectroscopy (EDS) was used to analyze the surface morphology. The surface characterization of the passive film formed on alloy specimens was also performed by using X-ray photoelectron spectroscopy (XPS). RESULTS In this study, bleaching agents had an effect on the anodic process for two groups. Although no statistical difference was identified between the groups for both corrosion parameters, results indicated that the effect of CP on the corrosion behavior was less than that of HP. These results agreed with the SEM observations. XPS data showed that oxide layers formed on all groups contained mainly Cr2 O3 , NiO, and MoO3 , and the amounts of oxides formed on CP-treated specimens were higher than HP treated ones. Also, molybdenum rates were increased with CP application compared to HP. CONCLUSIONS The comparison of the effects of the two bleaching agents at 10% showed that the alloy suffered less corrosion with CP than HP. This result was also confirmed by the SEM and XPS data. The presence of Mo on the oxide layer affected the oxide layer, leading to lower corrosion rates.

Farklı yüzey işlemlerinin porselen restorasyonların optik özelliklerine etkisi-Effect of Different Surface Treatments on Optical Properties of Porcelain Restorations

oz Amac: Calismanin amaci porselen yuzeyine uygulanan farkli bitirme tekniklerinin, farkli porselen sistemlerin optik ozelliklerine etkisini degerlendirmektir. Gerec ve Yontem: 3 farkli porselen sisteminden farkli kalinliklarda toplam 240 adet metal destekli porselenler yapildi. Orneklere Bulgular: Porselen yuzeylerine glazur, seramik lastigi, elmas pati veya lastik ile birlikte elmas pati uygulama, porselenin optik ozelliklerinde farkliliklar olusturdu ancak birbiri aralarinda anlamli fark bulunamadi (P>0.05). Yuzey islemleri sonrasinda tum porselen yuzeylerin L* degeri artarken, a* ve b* degerleri arasinda anlamli degisiklik bulanamadi. Dusuk isi porseleninin parlakligi tum yuzey islemleri sonrasinda, geleneksel porselenlere gore daha fazla artti. sonuc: Yuzey bitirme islemleri sonrasi porselen restorasyonlarda olusan renk degisimi klinik olarak kabul edilebilir duzeydedir. Anahtar kelimeler: Porselen, glazur, optik ozellikler, yuzey islemleri natural glazur (N), glazur (G), porselen lastigi (L), porselen elmas pati (EP), porselen lastigi ve elmas pat (L)+(EP) yuzey islemleri uygulandi. Orneklerin renk degerleri (L*,a*,b*) renk olcum cihaziyla belirlendi. Istatistiksel analizler ANOVA ve Tukey HSD, eslestirilmis iki grup t-test ile yapildi (P<0.05). abstract purpose: The purpose of the study was to evaluate the effect of different porcelain surface treatments on optical properties of different porcelain systems. Material and methods: Totally 240 metal-based porcelains were made by 3 different porcelain systems with different thicknesses. Different surface treatments as natural glaze (N), glaze (G), porcelain polish (L), porcelain diamond paste (EP), porcelain polish and diamond paste (L)+(EP) were applied on porcelain surfaces. Color values (L*,a*,b*) were determined with a color measurement device. Statistical analyses were performed with ANOVA and Tukey HSD, and Paired Sample t-test (P<0.05). Results: Glaze, porcelain polish, porcelain diamond paste or porcelain polisher and diamond paste; that applied on porcelain surfaces affected the optical properties of porcelains but there were no significant differences were found between them. After surface treatments as the L* value increased, there were no significant differences between a* and b* values. Lightness of low fusing porcelain increased more, when compared with feldspatic porcelains. Conclusion: After porcelain surface treatments color changes was found as clinically imperceptible. Keywords: Porcelain, glaze, optical properties, surface treatments