Evaluation of internal adaptation of flowable and bulk-fill resin-based composites

@#This study aimed to evaluate and compare the internal adaptation of bulk-fill resin-based composite restorative materials with flowable composites as lining materials using self-etch adhesive system. Class I cavities (2mmx4mm) were prepared on flattened occlusal surfaces of fifty extracted human premolars and randomly assigned into five groups (n=10) according to the materials used: Beautifil Bulk-fill Restorative (BR); Beautifil Bulk-fill Flowable (BF); Beautifil Flow Flowable F10 (BF10); and Self-etch adhesive (SEA). Group A: SEA+BR; Group B: SEA+BF10+BR; Group C: SEA+BF+BR; Group D: SEA+BF10+SEA+BR and Group E: SEA+BF+SEA+BR. The samples were thermocycled for 500 cycles, then sectioned mesiodistally, polished and pre-treated prior to scanning electron microscopy (SEM) evaluation. From SEM images, measurement of adhesive and cohesive adaptation failures was recorded at multiple sites of the pulpal floor and in between materials. Data were analysed using one-way ANOVA and post-hoc Tukey tests (p<0.05). Cohesive failure in SEA was observed at the pulpal floor with the lowest percentage in Group A (5.14%), and highest in Group C and E (>16%). However, there were no significant difference among all groups. Adhesive failure was seen at the pulpal floor between SEA+BF/BF10/BR and between SEA+dentine with the highest percentage of gaps formed in Group A between SEA+dentine (6.62%) and SEA+BR (5.30%). Nonetheless, no significant differences were observed among all groups with p=0.89 and p=0.70, respectively. With the use of BF/BF10 at the pulpal floor, adhesive failure was reduced but resulted in increased of cohesive failure. However, both adaptation failures were absent between materials (BF/BF10 and BR) regardless with or without application of SEA.

Comparative evaluation of the effect of a resin modified glass ionomer cement universal adhesive on the shear bond strength of glass ionomer cements

The present study compared and evaluated the shear bond strength (SBS) of two types of glass ionomer cement (GIC), Riva Self Cure HVTM (SDI Ltd., Victoria, Australia) and GC Fuji IX GP EXTRATM (GC America Inc., Alsip, USA) with and without the use of Riva Bond LCTM (SDI Ltd., Victoria, Australia), a lighted cured resin-modified glass ionomer cement (RMGIC) universal adhesive. Sixty extracted sound premolars with prepared exposure of the dentine on the occlusal surface were randomly assigned into four groups according to the tested restorative materials. Shear bond strength (SBS) tests were performed by using the Shimadzu Universal Testing Machine at a crosshead speed of 0.5 mm/minute, and the values obtained were statistically analysed using one-way ANOVA and Tukey tests. The inter-group comparison showed statistically significant differences in the SBS values between all the test groups (p 80%) compared to higher cohesive failures found in the non-adhesive groups (>86%). A Spearman's rho correlation test performed to determine the association between SBS values and mode of failures had indicated positive correlations between the adhesive failure and SBS values in the adhesive groups (rs=0.86, p<0.001; rs=0.85, p<0.001) and the cohesive failure and SBS values in the non-adhesive groups (rs=0.87, p<0.001). These findings support the improvement in adhesion of GICs to tooth structure with the use of RMGIC adhesive.

The Effect Of Different Dental Adhesive Systems On Hybrid Layer Qualities

The study aimed to evaluate the quality of the hybridlayer form by three different adhesive systems. Class Vcavities were prepared on the buccal surface of fourtyextracted human premolars. The prepared teeth wererandomly assigned into four groups according to theadhesive system and application mode. The systemswere: Optibond S (OS, total-etch); Optibond Versa (OV,two-bottles, self-etch); Single Bond Universal (SBU,one-bottle, self-etch) and Single Bond Universal withetchant (SBU + etchant). All cavities were restored withcomposite (Filtek Z350XT). The samples were sectioned,polished and pretreated to remove minerals, proteinand water prior to SEM evaluation. From the images,thickness of the hybrid layers was measured. Present ofresin tags and adaptation failure were also recorded. Thedata obtained were analyzed using ANOVA, Dunnett’sT3, Kruskal-Wallis and Mann-Whitney tests. OS groupshowed the highest average hybrid layer thickness (4.34µm), followed by SBU + etchant (3.06 µm), OV (1.91 µm)and SBU (0.95 µm). Both adhesive and cohesive failureswere observed in SBU group. Present of prominent resintags were seen in both OS and OV groups. In conclusion,all the investigated adhesive systems were able to performdistinguishable actions as shown in micro-morphologicalalteration and hybrid layer thickness. Two-bottles, selfetchadhesive (OV) was proven to produce negligibleadaptation failure compared to other adhesive systems inthe present study. Combined all-in-one adhesive (SBU)was found to render a superior bonding performance intotal-etch mode comparing to self-etch mode.

Shear bond strength of ceramic brackets bonded with antimicrobial monomer-containing self-etching primer / 대한치과교정학회지

OBJECTIVE: The purpose of this study was to determine (1) the shear bond strength (SBS) of an antimicrobial monomer-containing self-etching primer according to ceramic bracket types and (2) the bracket-adhesive failure mode using an adhesive remnant index (ARI). METHODS: A total of 90 extracted human teeth were randomly divided into 6 groups. Each group consisted of one of two ceramic brackets (monocrystalline, polycrystalline) and one of three primers (Transbond XT primer, Transbond Plus SEP, Clearfil Protect Bond) with each group containing 15 specimens. The SBS was measured, and adhesive residues left on the tooth surface were assessed. RESULTS: The SBS of polycrystalline ceramic bracket groups was significantly higher than that of the monocrystalline ceramic bracket groups (p < 0.001). The SBS of Transbond XT primer groups was significantly higher than those of Transbond Plus SEP groups and Clearfil Protect Bond groups (p < 0.001). All the groups showed bonding failures between the bracket base and adhesive. CONCLUSIONS: The combination of a self-etching primer with a monocrystalline bracket is recommended for clinical use, considering its acceptable SBS and mode of failure.

The shear bond strength and adhesive failure pattern in bracket bonding with different light-curing methods / 대한치과교정학회지

The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.