Betül Özçopur

An alternative adhesive strategy to optimize bonding to root dentin.

INTRODUCTION This study examined the hypothesis that the shear-bond strengths of AH Plus (AH) and Hybrid Root Seal (HRS) to root dentin might be optimized by using a powdered dentin-reinforced bonding procedure. METHODS The surfaces of root halves obtained from extracted human premolars were ground (800-grit silicon carbide paper), treated (5.25% NaOCl 17% EDTA for 5 minutes followed by distilled water) and randomly allocated into two groups according to the sealer and then into three subgroups according to bonding procedure. Dentin particles with a maximum size of 25 μm were incorporated into the adhesive of Clearfil Liner Bond 2V, and groups were created as follows: no adhesive, adhesive alone, and with powdered dentin reinforced adhesive; 3 × 3 mm high buildups were created using sealer and allowed to set (37 °C, 100% humidity, 72 hours). Shear tests were performed (1 mm/min). Data were calculated as MPa and analyzed (two-way analysis of variance, Tukey test). RESULTS A significant difference was found between the groups (P = .000). Adhesive or reinforced adhesive had a negative effect on the shear-bond strength of AH, but they significantly increased the shear-bond strength of HRS (P = .000). HRS showed a similar bond strength with either adhesive alone or adhesive reinforced with powdered dentin. AH group was characterized by mixed failure, whereas the predominant failure type of the HRS group was cohesive failure within the sealer. CONCLUSIONS Reinforcing adhesive resin with powdered dentin may be considered an alternative for optimizing the bonding of methacrylate-based sealers to root dentin and might affect the shear bond strength.

Effects of Ozone and Prophylactic Antimicrobial Applications on Shear Bond Strength of Orthodontic Brackets

Objective The present study aimed to evaluate the effects of ozone and prophylactic antimicrobial applications on the shear bond strengths and bond failure interfaces of orthodontic brackets. Methods Sixty human canine teeth were randomly divided into three groups (n=20), receiving the following treatments: Group I-pumice prophylaxis (Isler Dental, Ankara, Turkey)+37% orthophosphoric acid (Dentsply, Rio de Janeiro, Brazil)+Transbond XT primer and adhesive (3M Unitek, Monrovia, USA); Group II-prophylaxis paste (Topex, NJ, USA)+37% orthophosphoric acid (Dentsply, Rio de Janeiro, Brazil)+ Transbond XT primer and adhesive paste (3M Unitek, Monrovia, USA); and Group III-ozone application (Biozonix GmbH, Munich, Germany)+37% orthophosphoric acid (Dentsply, Rio de Janeiro, Brazil)+Transbond XT primer and adhesive (3M Unitek, Monrovia, USA). All specimens were stored at 37°C water for 24 h. Shear bond strength was assessed using a universal testing device (Autograph AGS-X; Shimadzu, Japan). Adhesive remnant index (ARI) scores were obtained through examination of teeth under stereomicroscope at 10× magnification after debonding. Results Shear bond strengths of orthodontic brackets were 16.10, 18.01, and 19.23 MPa for Groups I, II, and III, respectively. No statistically significant difference in shear bond strength of orthodontic brackets was found among the groups (p=0.273), based on Kruskal-Wallis analysis. Additionally, no significant difference was found in the ARI scores of each group using chi-square analysis (p=0.992). Conclusion Shear bond strength of orthodontic brackets and ARI scores was not found to be negatively impacted by ozone application.

The effect of Nd:YAG laser irradiation on root surface: shear-bond strength and SEM–EDX study

To investigate the effects of Nd:YAG laser and 17% EDTA treatment on root-dentin mineral content using scanning electron microscope–energy dispersive X-ray spectroscopy (SEM–EDX) and on shear-bond strength of epoxy-resin-based sealer (AH Plus) to root dentin. Twelve extracted premolars were decoronated and roots were sectioned, so that 24 two-root halves were obtained. Element levels of each half were examined by SEM/EDX, and AH Plus build-ups were created. After shear-testing, the test surfaces were reground and subjected to a 5.25% NaOCl. Two subgroups were created according to the surface treatment (n = 12): G1, with 17% EDTA for 5 min; G2, with the Nd:YAG laser. The element level analysis and shear-bond strength test were repeated for each half; the data were recorded (MPa) and analyzed (paired samples t-test). The EDTA treatment increased the O, C, Ca/P ratio (p < 0.001), decreased Ca, P content (p = 0.000), but did not change Na, Mg content (p > 0.05). The Nd:YAG laser increased O, Ca/P ratio (p < 0.001), and decreased the Ca, P content (p = 0.000). The C, Mg, Na content did not change with the Nd:YAG laser (p > 0.05). Both 17% EDTA and Nd:YAG laser had an effect on the mineral content of roots. The 17% EDTA treatment decreased the shear-bond strength of AH Plus to root dentin (p = 0.000); however, the Nd:YAG laser did not affect the bond strength (p = 0.238). Thus, an Nd:YAG laser can be used for disinfection of the root canal when AH Plus is used as a sealer.

Which is effective on bond strength of resin-based sealers: incorporation of powdered dentin to primer or adhesive?

The aim of this study was to investigate the effect of adding powdered dentin to primer or adhesive in a self-etch system on the shear bond strength of three resin-based sealers. Seventy-two premolars were sectioned buccolingually, and 144 root halves were divided into three groups according to the sealer used: epoxy resin-based sealer (AH Plus), methacrylate resin-based (RealSeal, Hybrid Root SEAL) n = 48. The surfaces were irrigated with 5% NaOCl, 17% EDTA, distilled water for 5 min. Four subgroups were created (n = 12): control group; Clearfil Liner Bond 2 V treated group; powdered dentin added to the primer of Clearfil Liner Bond 2 V (40 wt.%); and powdered dentin added to the adhesive of Clearfil Liner Bond 2 V (20 wt.%). Dentin powder was prepared. Three mm high buildups with a constant surface area of 3.45 mm2 were created using the sealers and allowed to set (37 ºC, 100% humid, 72 h). The samples were tested to failure for shear bond strength (1 mm/min). The data were calculated (MPa) and analyzed using two-way ANOVA, one-way ANOVA, and Tukey HSD tests. Adhesive use decreased the bonding performance of AH Plus (p = 0.00). Mean bond strength of the other sealers was found similar to control. Primer or adhesive resin with powdered dentin did not increase the adhesive performance of the self-etch system used. The shear bond strength of RealSeal was significantly increased when powdered dentin was added to primer or adhesive (p = 0.00). The effect of adding powdered-dentine to primer or adhesive in a self-etch system on the shear bond strength was sealer-dependent .

Perforasyon tamir materyallerinin sızıntı ve kalitesi: İntrakoronal ve retrograd tekniklerin karşılaştırılması

Amac: Bu in vitro calismanin amaci, perforasyon tamir materyallerinin, perforasyon bolgesine ortograd ya da retrograd yerlestirildiginde, sizinti ve kalitesini degerlendirmektir. Gerec ve Yontemler: Cekilmis insan molar dislerin mesial ve distal kok yuzeylerinde, disin uzun aksina 45 derecelik aciyla elmas bir frez ile kasten perforasyonlar olusturuldu. Mesial perforasyonlar intrakoronal olarak su materyaller kullanilarak tamir edildi: IRM (Dentsply), amalgam (Dentsply), Dyract (Dentsply), SuperBond C&B (Sun Medical) and MTA (Dentsply). Siman ile giris kavitesi doldurulduktan sonra distal perforasyonlar ayni materyaller ile retrograd olarak tamir edildi. Disler %100 nemli ortamda 24 saat saklandi. Perforasyon bolgeleri 24 saat %2’lik metilen mavisinde bekletildi. Disler kesilerek, 20x ve 40x buyutme ile stereomikroskop altinda incelendi ve boya penetrasyonuna gore tasmis, yeterli ve yetersiz olarak skorlandi. Bulgular: Veriler Kruskal-Wallis ve MannWhitney U-testleri ile analiz edildi. Restorasyon teknikleri arasinda onemli derecede fark bulundu (p < 0.05). Tum materyallerde retrograd teknik kullanildigi zaman daha az sizinti gozlendi (p < 0.05). Giris kavitesi boyunca perforasyonun tamiri, %86 tasmis ya da yetersiz bulundu. Retrograd olarak uygulandigi zaman IRM %80, MTA %60 oraninda sizinti olmadan yeterli bulundu. Sonuc: Retrograd teknik kullanarak perforasyonlarin tamiri, kullanilan materyalin etkisi olmaksizin yeterli restorasyonun sayisi onemli derecede artti. IRM retrograd uygulandigi zaman MTA’yi takiben en iyi kapamayi sagladi.