Mechanical properties and repair bond strength of polymer-based CAD/CAM restorative materials

Information on the mechanical properties and repairability of computer-aided design/computer-aided manufacturing (CAD/CAM) blocks is scarce. Five CAD/CAM blocks with similar indications were evaluated, including four resin nanoceramics, one polymer-infiltrated ceramic network (PICN), and one feldspathic ceramic. CAD/CAM blocks were sectioned into 4 mm x 1.2 mm x 13 mm bars for flexural strength (FS), and 4 mm thick blocks were prepared for elastic modulus (EM), nanohardness (NH), and microshear bond strength (mu SBS) testing. FS of the CAD/CAM blocks was determined using a three-point bending test, whereas EM and NH values were measured using a nanoindenter. The reparability of the tested block materials was determined by the mu SBS test. One-way ANOVA was conducted for FS, EM, NH, and mu SBS followed by Tukey's pairwise comparison (alpha < 0.05). FS ranged from 115 to 207 MPa, EM from 8.21 to 44 GPa, NH from 0.76 to 7.24, and mu SBS from 24.9 to 30.6 MPa. The findings of the present study revealed that resin nanoceramic blocks exhibited higher FS values than PICN and feldspathic ceramic, and they have acceptable mechanical properties for the fabrication of single-unit restorations according to the ISO 6872:2008. Furthermore, all CAD/CAM blocks tested can be successfully repaired regarding their recommended repair protocol

Effect of surface treatments and universal adhesive application on the microshear bond strength of CAD/CAM materials

PURPOSE. The aim of this study was to evaluate the microshear bond strength (mu SBS) of four computer-aided design/computer-aided manufacturing (CAD/CAM) blocks repaired with composite resin using three different surface treatment protocols. MATERIALS AND METHODS. Four different CAD/CAM blocks were used in this study: (1) flexible hybrid ceramic (FHC), (2) resin nanoceramic (RNC), (c) polymer infiltrated ceramic network (PICN) and (4) feldspar ceramic (FC). All groups were further divided into four subgroups according to surface treatment: control, hydrofluoric acid etching (HF), air-borne particle abrasion with aluminum oxide (AlO), and tribochemical silica coating (TSC). After surface treatments, silane was applied to half of the specimens. Then, a silane-containing universal adhesive was applied, and specimens were repaired with a composite, Next, mu SBS test was performed. Additional specimens were examined with a contact profilometer and scanning electron microscopy. The data were analyzed with ANOVA and Tukey tests. RESULTS. The findings revealed that silane application yielded higher mu SBS values (P<.05). All surface treatments were showed a significant increase in mu SBS values compared to the control (P<.05). For FHC and RNC, the most influential treatments were AlO and TSC (P<.05). CONCLUSION. Surface treatment is mandatory when the silane is not preferred, but the best bond strength values were obtained with the combination of surface treatment and silane application. HF provides improved bond strength when the ceramic content of material increases, whereas AlO and TSC gives improved bond strength when the composite content of material increases

Efficacy of different surface treatments and universal adhesives on the microtensile bond strength of bulk-fill composite repair

The purpose of this in vitro study was to evaluate the influence of different surface treatments and aging on the microtensile bond strength (mu TBS) of bulk-fill composite resins. Bulk-fill composites (Filtek One; 3M ESPE) randomly received five different surface treatments: (1) no treatment, control, (2) 37% phosphoric acid etching (PA), (3) 9% hydrofluoric acid etching (HF), (4) air-borne particle abrasion with 50-mu m alumina particles (Al2O3), (5) tribochemical silica coating (CoJet). Following, the specimens were divided into three subgroups according to universal adhesive applied: Clearfil Universal Bond (CU; Kuraray), Prime&Bond Universal (PBU; Dentsply Sirona), or Single Bond Universal (SBU; 3M ESPE). A nanofill composite (Filtek Ultimate; 3M ESPE) was employed as a repair. Bonded specimens were stored in water for 24 h at 37 degrees C or thermal aged, then subjected to the mu TBS test. Additionally, specimens were analyzed with a contact profilometer and were evaluated with scanning electron microscopy. Control and PA treatments were showed the lowest mu TBS (p 0.05). Al2O3 and CoJet treatments generally exhibited a similar influence on mu TBS values. In addition, a correlation was found between surface roughness and bond strength (r = 0.831). CoJet resulted in significantly higher repair mu TBS values when compared to the other surface treatments. In addition, the use of silane-containing universal adhesive was increased the cohesive failure rate and maintained the repair mu TBS values after thermocycling

Yaşa bağlı maküla dejenerasyonu hastalarında fotodinamik tedavi sonuçları

Purpose: To evaluate the efficacy of photodynamic therapy in patients who had choroidal neovascularization due to agerelated macular degeneration (AMD). Materials and Methods: Data on 30 eyes of 30 patients were evaluated. Sixteen patients were men and 14 were women. Mean age was 68.4;plusmn;8.74 (47 to 81 years) years. Mean follow-up time was 15.7;plusmn;3.28 months (10-22 months). The patients;amp;#8217; best corrected visual acuities were measured by Early Treatment of Diabetic Retinopathy Study (ETDRS) chart number 2 and lesion types and the GLD of the lesions were measured by Topcon Image Net Fundus Camera. The indication for photodynamic therapy was based on the European Ophthalmology Society;amp;#8217;s criteria published in 2001. The patients were invited to undergo control examinations 1 week and 3 months after the therapy and thereafter every 3 months. In each control examination the best corrected visual acuity was checked by ETDRS chart, fundus examinations were performed and fundus photographs were recorded by fundus camera, and FFA examinations was performed, especially in the first and second controls. Results: After 2;plusmn;1.44 therapies (ranging from 1 to 5) 22 patients (73.3%) could have been treated, but 8 patients (27.7%) had persistent CNVs. There was no significant difference in visual loss between the two groups but the loss in the successful group was 1.5 LogMAR standard lines less than that in the unsuccessful group.Amaç: Bu çalışmada fotodinamik tedavinin yaşa bağlı maküla dejenerasyonda gelişen koroidal neovaskülarizasyonların tedavisindeki etkinliği değerlendirildi. Gereç ve Yöntem: Çalışmaya 30 hastanın 30 gözü alındı. Hastaların 16’sı (%53.3) erkek, 14’ü (%47.7) kadındı. Hastaların yaş ortalaması 68.4±8.74 (47-81 yaş), ortalama takip süresi 15.7±3.28 ay (10-22 ay) idi. Tedavi öncesi hastaların en iyi düzeltilmiş görme keskinlikleri Early Treatment of Diabetic Retinopathy Study 2 numaralı eşeli ve lezyon tipleri ve lezyon büyüklükleri fundus kamera ile ölçüldü. Hastalara fotodinamik tedavi endikasyonu Avrupa Oftalmoloji Cemiyeti’nin 2001 yılında yayınladığı rehbere göre kondu. Hastalar FDT sonrası 1. hafta, 3. ay ve sonrasında her üç ayda bir kontrol edildi. Kontrollerde ETDRS eşeli ile en iyi düzeltilmiş görme keskinlikleri, fundus muayeneleri ve fundus kamera ile renkli fundus görüntüleri alındı ve özellikle ilk ve ikinci kontrollerde FFA’ları çekildi. Hastalar kontrollerinde FFA’daki florosein sızdırma özelliklerine göre dört gruba ayrıldılar ve sızıntının olmadığı durumlar ile sızıntının %50’den daha az hale geldiği durumlarda tedavi başarılı, sızıntının %50’den fazla olduğu durumlarda ise başarısız kabul edildi. Bulgular: Ortalama 2±1.44 (1-5) seanslık tedavi sonucunda 22 (%73.3) olguda KNV’nin gerilediği, 8 (%27.7) olguda ise KNV’nin devam ettiği tespit edildi. Başarılı grupla başarısız grup görme kaybı açısından değerlendirildiğinde başarılı grupta ortalama 1.5 LogMAR standart sırası daha az görme kaybı gelişti fakat aradaki fark istatistiksel olarak anlamlı değildi. (p=0.101). Tartışma: Sonuç olarak Verteporfin ile FDT ile Eksudatif tip YBMD tedavisinde etkili ve güvenli bir yöntemdir