Effects of Saliva Contamination on Shear Bond Strength with Conventional, Moisture Insensitive, and Self-Etching Primers / 대한소아치과학회지

The aim of this study was to compare the shear bond strengths of orthodontic bracket with Conventional primer (CP), Moisture insensitive primer (MIP), and Self-etching primer (SEP). In addition, the effect and the timing of saliva contamination on shear bond strength was evaluated.A total of 135 bovine mandibular incisors were used in the study and divided into 3 groups. Group I, II and III were used CP, MIP, SEP, respectively. Each group was then divided into three subgroups: the group without saliva contamination, the group with primer application after saliva contamination, and the group with saliva contamination after primer application. After the primer application, the metal bracket for the lower incisor was attached and the shear bond strength was measured.The mean shear bond strengths was highest with CP and lowest with SEP in dry condition. However, CP showed a significant decrease in shear bond strength in the presence of saliva contamination. MIP and SEP showed no significant decrease in shear bond strength with saliva contamination.

The influence of different etching adhesive systems on flowable resin used as pit and fissure sealant / 实用口腔医学杂志

Objective:To evaluate the effects of the flowable resin used as pit and fissure sealant using different etching adhesive systems.Methods:60 caries-free extracted human premolars were randomly divided into 4 groups(n =1 5)and treated by Gluma, NT and 3M-Z350 flowable resin(group A);Clearifil SE Bond adhesive and 3M-Z350 flowable resin(group B),phosphoric acid etching,3M-Z350 flowable resin and phosphoric acid etching(group C)and 3Mconcise sealant(group D)respectively.After pro-cessing the tooth surface the pit and fissue of 1 0 sample in each group were sealed.The microleakage was measured by 1 % methyl-ene blue staining(n =8).The material-enamel interface was observed by SEM(n =2).The shear bond strength of the column-shaped samples with the diameter and the height of 3 mm(n =5)on the mesial or dental surface was examined by a test machine. The sealant cartridges and flowable resin cartridges with the diameter and height of 4 mm were used for the crushing strength exami-nation(n =1 0).Results:There was no significant difference in the microleakage among the 4 groups.SEMobservation showed that the resin tags of group A were long and dense and the resin tags of group B were short and sparse,bubbles and cracks were found on the local site in group A and B.The resin tags of group C were long and thin,but combined with tooth tightly;the resin tags of group D were short and dense;the penetration was poor at the bottom of the fissures in the 4 groups.The shear bond strength of Group A was the highest(P 0.05).The compressive strength of flowable resin groups was higher than that of fissure seal-ant group(P <0.05).Conclusion:The shear bond strength and compressive strength of all-etching bonding system combined with flowable resin is superior to that of self-etching bonding system combined with flowable resin and the traditional sealant.Using Prime&Bond NT bond after acid etching may improve the shear bonding strength.

Evaluation of flexural bond strength of porcelain to used nickel-chromium alloy in various percentages.

Aim: The aim of this in vitro study was to evaluate the flexural bond strength of porcelain to combinations of used and new nickel-chromium alloy in various proportions. Materials and Methods: Used and new nickel-chromium bonding alloys were combined in various proportions (groups I to V; 10 samples per group) and their flexural bond strengths with porcelain were compared. A three-point loading system was used for the application of load. Load was applied at a constant speed of 0.5 mm/minute and the load required to fracture the porcelain was recorded for each specimen. Statistical Analysis Used: (a) Analysis of variance (ANOVA) and (b) Duncan's multiple range tests. Results: The best bond strength values were seen when 100% new alloy was used. According to the findings of this study, there was no adverse effects noted with up to 75% recast metal, but serious changes were found in the bond strength values when 100% old metal was used. Conclusions: The following conclusions were drawn from the study Fresh nickel-chromium alloy shows the greatest porcelain adherence. There is no significant change in bond strength of ceramic to alloy with up to 75% of used nickel-chromium alloy. At least 25%- of new alloy should be added when recycled nickel-chromium alloy is being used for metal ceramic restorations.

Comparative evaluation of effects of different surface treatment methods on bond strength between fiber post and composite core

PURPOSE: Debonding of a composite resin core of the fiber post often occurs at the interface between these two materials. The aim of this study was to evaluate the effects of different surface treatment methods on bond strength between fiber posts and composite core. MATERIALS AND METHODS: Sixty-four fiber posts were picked in two groups (Hetco and Exacto). Each group was further divided into four subgroups using different surface treatments: 1) silanization; 2) sandblasting; 3) Treatment with 24% H2O2, and 4) no treatment (control group). A cylindrical plexiglass matrix was placed around the post and filled with the core resin composite. Specimens were stored in 5000 thermal cycles between 5degrees C and 55degrees C. Tensile bond strength (TBS) test and evaluation using stereomicroscope were performed on the specimen and the data were analyzed using two-way ANOVA, Post Hoc Scheffe tests and Fisher's Exact Test (alpha=.05). RESULTS: There was a significant difference between the effect of different surface treatments on TBS (P<.001) but different brands of post (P=.743) and interaction between the brand of post and surface treatment (P=.922) had no significant effect on TBS. Both silanization and sandblasting improved the bonding strength of fiber posts to composite resin core, but there were not any significant differences between these groups and control group. CONCLUSION: There was not any significant difference between two brands of fiber posts that had been used in this study. Although silanization and sandblasting can improve the TBS, there was not any significant differences between surface treatments used.

Influence of Sodium Ascorbate on Microtensile Bond Strengths to Pulp Chamber Dentin treated with NaOCl / 대한치과보존학회지

The purpose of this study was to evaluate the influence of sodium ascorbate on microtensile bond strengths of total-etching adhesive system to pulp chamber dentin treated with NaOCl. Pulp chambers of extracted human non-caries permanent molars were treated as follows: group 1, with 0.9% NaCl; group 2, with 5.25% NaOCl; group 3, with 5.25% NaOCl and 10% sodium ascorbate for 1min; group 4, with 5.25% NaOCl and 10% sodium ascorbate for 1 min and 10ml of water; group 5, with 5.25% NaOCl and 10% sodium ascorbate for 5 min; group 6, with 5.25% NaOCl and 10% sodium ascorbate for 5 min and 10ml of water; group 7, with 5.25% NaOCl and 10% sodium ascorbate for 10 min; group 8, with 5.25% NaOCl and 10% sodium ascorbate for 10 min and 10ml of water. Treated specimens were dried, bonded with a total-etching adhesive system (Single bond), restored with a composite resin(Z250) and kept for 24h at 100% humidity to measure the microtensile bond strength. NaOCl-treated group (group 2) demonstrated significantly lower strength than the other groups. No significant difference in microtensile bond strengths was found between NaCl-treated group (group 1) and sodium ascorbate-treated groups (group 3-8). The results of this study indicated that dentin treated with NaOCl reduced the microtensile bond strength of Single bond. Application of 10% sodium ascorbate restored the bond strength of Single bond on NaOCl-treated dentin. Application time of sodium ascorbate did not have a significant effect.

Effect of thermal cycling on resin-dentin interface of two bonding agents / 吉林大学学报(医学版)

0.05);) Single Bond provided significantly higher shear bond strengths than Adper Prompt in all groups((P