Effects of polishing procedures on color stability of composite resins

The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish system (PdB and PdPB groups)

Effects of air-polishing powders on color stability of composite resins

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (∆E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (

Effects of air-polishing powders on color stability of composite resins

OBJECTIVES: The purpose of this study was to investigate the effect of different air-polishing powders on the color stability of different types of composite resin restorative materials. MATERIAL AND METHODS: Thirty cylindrical specimens (15×2 mm) were prepared for each of 7 composite resin restorative materials. All specimens were polished with a series of aluminum oxide polishing discs (Sof-Lex). The prepared specimens of each composite resin were randomly divided into 3 groups of 10 specimens each, for control (Group-C) and two air-powder applications (Group-CP: Cavitron Prophy-Jet; Group-PS: Sirona ProSmile prophylaxis powder). A standard air-polishing unit (ProSmile Handly) was used. All specimens were air-powdered for 10 s at 4-bar pressure. The distance of the spray nosel from the specimens was approximately 10 mm and angulation of the nosel was 90°. Specimens were stored in 100 mL of coffee (Nescafe Classic) for 24 h at 37°C. Color measurement of all specimens was recorded before and after exposure to staining agent with a colorimeter (Minolta CR-300). Color differences (&#8710;E*) between the 2 color measurements (baseline and after 24 h storage) were calculated. The data were analyzed with a 2-way ANOVA test, and mean values were compared by the Tukey HSD test (p.05) and these groups demonstrated the highest &#8710;E* values. For Filtek Silorane and IntenS, the highest &#8710;E* values were observed in Group-PS. The lowest &#8710;E* values for all composite resin groups were observed in Group-C. When comparing the 7 composite resin restorative materials, Aelite Aesthetic Enemal demonstrated significantly less &#8710;E* values than the other composite resins tested. The highest &#8710;E* values were observed in Quixfil. CONCLUSION: Except for Quixfil, all control groups of composite resins that were polished Sof-Lex exhibited clinically acceptable &#8710;E values (<3.7). Air-polishing applications increased the color change for all composite resin restorative materials tested. Composite restorations may require re-polishing after air-polishing

Pulpal blood flow changes in abutment teeth of removable partial dentures

The purpose of this study was to investigate the effect of tooth supported (TSD) and toothtissue supported (TTSD) removable partial denture wearing on pulpal blood flow (PBF) of the abutment teeth by using Laser Doppler Flowmeter (LDF). Measurements were carried out on 60 teeth of 28 patients (28 teeth and 12 patients of TTSD group, 32 teeth and 16 patients of TSD group) who had not worn any type of removable partial dentures before, had no systemic problems and were non smokers. PBF values were recorded by LDF before insertion (day 0) and after insertion of dentures at day 1, day 7 and day 30. Statistical analysis was performed by student t test and covariance analyses of repeated measurements. In the group TTSD, the mean values of PBF decreased statistically significantly at day 1 after insertion when compared with PBF values before insertion (p<0,01). There was no statistically significant difference among PBF mean values on 1st, 7th and 30th day. However, in the group TSD, there was no statistically significant difference among PBF mean values before insertion and on 1st, 7th and 30th day. In other words, PBF mean values in group TSD continued without changing statistically significant on 1st, 7th and 30th day. TTSD wearing may show negative effect on the abutment teeth due to decreasing basal PBF

Pulpal blood flow changes in abutment teeth of removable partial dentures

The purpose of this study was to investigate the effect of tooth supported (TSD) and toothtissue supported (TTSD) removable partial denture wearing on pulpal blood flow (PBF) of the abutment teeth by using Laser Doppler Flowmeter (LDF). Measurements were carried out on 60 teeth of 28 patients (28 teeth and 12 patients of TTSD group, 32 teeth and 16 patients of TSD group) who had not worn any type of removable partial dentures before, had no systemic problems and were non smokers. PBF values were recorded by LDF before insertion (day 0) and after insertion of dentures at day 1, day 7 and day 30. Statistical analysis was performed by student t test and covariance analyses of repeated measurements. In the group TTSD, the mean values of PBF decreased statistically significantly at day 1 after insertion when compared with PBF values before insertion (p<0,01). There was no statistically significant difference among PBF mean values on 1st, 7th and 30th day. However, in the group TSD, there was no statistically significant difference among PBF mean values before insertion and on 1st, 7th and 30th day. In other words, PBF mean values in group TSD continued without changing statistically significant on 1st, 7th and 30th day. TTSD wearing may show negative effect on the abutment teeth due to decreasing basal PBF

Prostodonti Klinik Havasının Mikrobiyal Düzeyi Üzerine Havalandırma-Klima Sisteminin Etkisi

Amaç: Prostodonti kliniği havasının mikrobiyolojik kalitesi üzerine havalandırma-klima sisteminin etkisinin ortaya konulmasıdırGereç ve Yöntemler:Bioaerosol örnekler Ondokuz Mayıs Üniversitesi, Diş Hekimliği Fakültesi, Protez kliniğinden toplanmıştır. Havalandırma sistemi toplam 7485 m3/s havalandırma kapasitesine sahiptir. Bu sisteminin etkinliğinin değerlendirilmesi amacıyla, havalandırma sistemi kapatılarak, klinik gün boyu rutin çalışmasına devam etmiştir. Gün sonunda ise toplam mezofilik aerobik bakteri ve mantar sayısının belirlenmesi amacıyla ayrı ayrı 10’ar örnek toplanmıştır. Bu örneklemeden sonra, aynı işlem havalandırma sistemi gün boyunca çalıştırılmış ve gün sonunda aynı şekil ve sayıda örnekleme yapılmıştır. Hava örneklemesinde MAS 100 (Merck, Germany) hava örnekleme cihazı kullanılmıştır. Her 15 günde bir akşam ve sabah olmak üzere toplamda 12 dönemde 480 örnek alınmıştır. Toplam mezofilik aerobik bakteri sayısının belirlenmesinde Nutrient Agar, toplam mantar sayısının belirlenmesinde ise % 1 Penisilin içeren Sabouraud Dekstroz Agar kullanılmıştır. Alınan örnekler sırasıyla 35 ºC’de 48-72 saat ve 25 ºC’de 5 gün inkubasyona bırakılmıştır. İnkubasyon sonrası oluşan koloniler sayılarak metreküpteki bakteri ve mantar sayıları koloni oluşturma ünitesi (CFU/m3) şeklinde ifade edilmişlerdir. Sonuçların istatiksel olarak hesaplanmasında Feller doğrulaması kullanılmıştır. Elde edilen veriler student T testi ile değerlendirilmiştir. Analizler SAS 9.01 istatistik paket programında yapılmıştır.Bulgular: Havalandırma siteminin kapalı ve açık olduğu durumda hem toplam aerobik mezofilik bakteri, hem de toplam mantar sayılarında istatistiksel olarak anlamlı ölçüde (p&lt;.0001) değişim gözlenmiştir. Gözlenen farklılık azalma yönündedir. Sonuçlar:Diş kliniklerinde havanın mikrobiyolojik kalitesini kontrol etmek ve hekimler ve hastalar için enfeksiyon riskini azaltmak için kliniklerde yapısal olarak etkin önleyici önlemlerin alınması ve bu amaçla standartların oluşturulması gereklidir.Anahtar Kelimeler