Background Fracture or chipping are major concerning failures of an all-ceramic restoration. Repairing of the failure restoration using intra-oral technique is time saving and cost effective treatment modality. The present study was proposed to evaluate effect of Er,Cr:YSGG laser irradiation on shear bond strength between zirconia/porcelain and composite resin. Methods Thirty zirconia and thirty zirconia based porcelain disc shape specimens were prepared. Three different surface treatment procedure were applied the specimens. For control groups (Group ZC and PC), instruction manual of an intra-oral porcelain repair system was followed. Different pulse rates of Er,Cr:YSGG laser irradiation (short and long pulses) were applied to zirconia and porcelain surfaces for other groups (Group ZS, ZL, PS, and PL). Porcelain repair kit was used to repair specimens using standard cylindrical teflon mold (2 × 2 mm). Repair bond strength of the repaired specimens was tested using a universal testing machine. Results Highest mean bond strength value was observed at Group PC that was significantly higher than laser applied porcelain groups. Long pulse laser irradiation illustrated that increased mean bond strength compared to short pulse application on to the porcelain surface. Laser applied zirconia groups showed better mean bond strength than Group ZC, but differences between the groups were not statistically significant. Conclusion Different modes of Er,Cr:YSGG laser irradiation enhanced repair bond strength of the composite resin to zirconia, but these were not significant. Following the instruction manual for surface treatment on the porcelain surface was better method than Er,Cr:YSGG laser surface conditioning.

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The aim of this study was to investigate the effects of different surface treatment methods on shear bond strength between composite resin and different levels of zirconia ceramic. Laser surface-conditioning procedures have been reported as effective method to increase repair bond strength of composite to zirconia ceramics. Detailed information of effects of Er,Cr:YSGG laser treatment with different pulse rates on the zirconia ceramics is lacking in the literature. 120 disc-shaped specimens were prepared including zirconia, veneering ceramic, and 50% veneering ceramic-50% zirconia surfaces. Four different surface treatments were applied to the specimens. These were grinding with diamond bur, sandblasting, and short and long pulse rates of Er,Cr:YSGG laser irradiation. An intraoral ceramic repair kit was used to repair specimens, and shear bond strength was performed on the composite resin to each specimen. The highest mean bond strength was seen in the veneering ceramic surface that was ground using a diamond bur, and the lowest mean bond strength value was observed in the same surface that was treated with long pulse laser irradiation. The sandblasting with alumina particles exhibited lower mean repairing bond strength among the rest of used methods in this study for the group which contained half of the veneering ceramic and half of the zirconia. Sandblasting and Er,Cr:YSGG laser using surface treatment procedures obtained appropriate bond strength for the group that included 50% veneering ceramic-50% zirconia, because of no significant differences observed among the applied surface conditioning methods in this group.

Precision attachments have been used for many years to retain removable partial dentures (RPDs). Common reasons for a failed attachment-retained RPD are fracture of the framework, fracture of the roots or teeth, and irretrievable decrease of retention. When an RPD framework major connector has been fractured, it should be remade. This article describes a technique to remake a fractured mandibular RPD using cast round profile attachment analogs without the need for replacement of the fixed partial denture.

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Objective: To investigate the mechanical properties of various mass fractions of Nylon 6 (N6), polymethyl-metacrylate (PMMA) and polyvinylidene-difluoride (PVDF) nanofibres reinforced bisphenol A-glycidyl methacrylate (Bis-GMA) and tri-ethylene glycol dimethacrylate (TEGDMA) based dental composite resins and to evaluate the penetration characteristics of the nanofibres into the resin. Methods: Nylon 6, PMMA and PVDF nanofibres were produced using the electrospinning method. The morphologies of the fabricated nanofibres were evaluated with a scanning electron microscope (SEM). The nanofibres were placed into the resin matrix at different mass fractions (3%, 5% and 7%). The three-point bending test was applied to nanofibre-reinforced dental composite resins and neat resin specimens. The flexural strength (Fs), flexural modulus (E Y ) and work of fracture (WOF) of the groups were found. The analysis of variance was used for the statistical analysis of the acquired data. Tukey's multiple test was performed to compare the Fs, E Y and WOF means. Fractured surfaces of the samples were observed by SEM, and fracture morphologies were evaluated. Results: Polymethyl-metacrylate nanofibres dissolved in the matrix, and a polymer alloy took place in the matrix. Fibre pull-out and fibre bridging mechanisms were observed by SEM images of the N6 and PVDF nanofibre-reinforced dental composites. The produced nanofibres enhanced the mechanical properties of the dental composite resins. Conclusion: Fibre pull-out and fibre bridging mechanisms on the fractured surfaces of samples may play a key role in the reinforcement of dental composite resins. However, polymer alloy of PMMA nanofibres increased the mechanical properties of the resin matrix.

Çalışmamızın amacı iki farklı ağız içi porselen tamir seti (APTS) kullanılarak kompozit rezinle tamir edilen zirkonya restorasyonlarda dört farklı yüzey hazırlık yönteminin renge olan etkilerinin değerlendirilmesidir. Gereç ve yöntem: Disk şeklinde (2 x 5 mm) 80 adet zirkonya ve 80 adet zirkonya destekli porselen örnek hazırlanmıştır. Örneklerin L*a*b* değerleri kaydedilmiş ve iki farklı APTS (Clearfil Repair ve Ceramic Repair N) için porselen ve zirkonya örnekler ikiye ayrılmıştır. Bu ana gruplarda 40 örnek dört farklı yüzey hazırlık işleminin (elmas frezle pürüzlendirme, ağız içi kumlama, uzun ve kısa atım Er,Cr:YSGG lazer ışınlama) uygulanması için 4 alt gruba (N = 10) daha ayrılmıştır. APTS'leri ve bu kitlerle uyumlu kompozit rezinler (Clearfil Majesty Esthetic ve Tetric N Ceram) örnek yüzeylerine tatbik edilmiştir. Kompozit rezinler her bir zirkonya ve porselen yüzeyine standart bir teflon kalıp (2 x 2 mm) kullanılarak inkremental teknikle yerleştirilmiştir. Tamir edilen örnek yüzeylerinde L*a*b* değerleri kaydedilmiş olup, ilgili formül kullanılarak ΔE değerleri hesaplanmıştır. Başlangıç ve sonuç renk farklılıkları kaydedilip istatistiksel analiz (tek yönlü varyans analizi) yapılmıştır. Bulgular: APTS ve yüzey hazırlık işlemlerine göre hesaplanan renk farklılıkları klinik olarak kabul edilebilir değerden (∆E = 5.5) yüksektir. Zirkonya destekli porselen örneklerde uzun atım lazer ışınlaması ve Clearfil Repair APTS uygulanan grup en düşük ∆E değerini (∆E = 5.90) göstermiştir. Kısa atım lazer ışınlaması ve Clearfil Repair APTS uygulandığı zirkonya örneklerin grubu diğer gruplara göre en yüksek renk değişikliğini (∆E=13.65) sergilemiştir. Sonuç: Tamir edilen zirkonya ve zirkonya destekli porselenlerin ilk renklerine göre renk farklılıkları; tiplerine, kullanılan yüzey hazırlık yöntemlerine ve uygulanan APTS'lerine bağlı olmaksızın klinik olarak kabul edilebilir değildir.

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