Effects Of Blood Contamination On Performance Of Self-etching Primer Combined With Resin-modified Glass Ionomer Cement

Blood contamination can affect the shear bond strength of the bracket materials. Microleakage increases the likelihood of recurrent caries and postoperative sensitivity. Research has proved that self-etching adhesive system and RMGIC (Resin-modified glass ionomer cement), which developed as newly adhesive materials in stomatology, have strong tolerance with saliva contamination. However, studies on blood contamination and microleakage are few. We studied the effect of blood contamination on shear bond strength and microleakage on beneath brackets of SEP and RMGIC.Trial 1: Effect of re-etching after blood contamination on the shear bond strength of light-cured resin-modified glass ionomer cementObjective: To evaluate the effect of re-etching after blood contamination on the shear bond strength of light-cured resin-modified glass ionomer cement(RMGIC).Materrials: Sixty extracted human premolars for orthodontic purposes; SEP (self-etching primer); RMGIC (resin-modified glass ionomer cement); 35%phosphoric acid; Composite Resin adhesive; 10ml fresh human blood from a male donor.Methods: Sixty extracted human premolars for orthodontic purposes were randomly separated into 6 groups, with 10 speciments in each group: composite resin control group, etching for 30 seconds, drying, and composite resin bonding; RMGIC control group, etching for 30 seconds, wetting, and RMGIC bonding; RMGIC un-etching group, unetching, wetting, and RMGIC bonding; RMGIC etched-blood contamination group, etching for 30 seconds, blood contamination, re-etching for 30 seconds, and RMGIC bonding; RMGIC unetched-blood contaminating group, unetching, blood contamination, and RMGIC bonding.Results: Subsequent to the etching with 35% phosphoric acid for 30 seconds, RMGIC was similar to the composite resin regarding the bond strength, many remnant adhesives were observed on facing after removing the brackets. Subsequent to the blood contamination, the bond strength of RMGIC decreased, with many remnant adhesives on facing. Re-etching exhibited no influence on the bond strength. There were significantly lower bond strengths and fewer remnant adhesives in the unetching group.Conclusion: The re-etching after blood contamination does not affect the bond strength of RMGIC. But re-etching for 30 seconds may adequate bond strengths for use.Trial 2: Effects of blood contamination on shear bond strength of self-etching adhesive system Objective: To evaluate the effect of blood contamination on shear bond strength of self-etching adhesive system.Materials: Sixty extracted human premolars for orthodontic purposes; SEP (self-etching primer); RMGIC (resin-modified glass ionomer cement); 37%phosphoric acid; Fresh human blood 10ml from a male donor.Methods: Sixty extracted human premolars for orthodontic purposes were randomly separated into 6 groups, with 10 speciments in each group. The phosphoric acid-etching group was treated with phosphoric acid and bonding with resin-modified glass ionomer cement (RMGIC); the self-etching primer (SEP) group: SEP treated, and RMGIC bonding; the phosphoric acid-etching-blood contamination group: phosphoric acid treated, blood contamination, and RMGIC bonding; the SEP-blood contamination group: SEP treated, blood contamination, and RMGIC bonding; the blood contamination-SEP group: blood contamination, treated with SEP, and RMGIC bonding; the SEP-blood contamination-SEP group: SEP treated, blood contamination, retreated with SEP, and bonding with RMGIC.Results: The shear bond strength in the phosphoric acid-etching, SEP-etching and blood contamination-SEP groups were stronger than that of the phosphoric acid-etching-blood contamination, SEP-blood contamination and SEP-blood contamination-SEP groups (P < 0.001). The adhesive remnant index scores in different groups were as follow: the phosphoric acid-etching group: 2 or 3; the SEP-etching group: 1 or 2; the blood contamination group: mostly 0 or 1, few 2; the blood contamination-SEP group: scattered from 0, 1, 2, or 3.Conclusion: The blood contamination after etching decreased the bond strength of RGIC, but for contamination before SEP, the bond strength of RMGIC is not significant affected.Trial 3: Effect of blood contamination on microleakage beneath brackets with newly adhesive systemObjective: To evaluate the effect of blood contamination on microleakage beneath brackets with newly adhesive system.Materials:Fifty extracted human premolars for orthodontic purposes; SEP (self-etching primer); RMGIC (resin-modified glass ionomer cement); 37%phosphoric acid; Composite Resin adhesive; 10 ml fresh human blood from a male donor.Methods: Group A: 37% phosphoric acid + conventional resin; Group B: SEP + RMGIC + light-cured; Group C: blood contamination + SEP + RMGIC + light-cured; Group D: SEP + blood contamination + RMGIC + light-cured; Group E: SEP + blood contamination + SEP + RMGIC + light-cured. Results: The micro-leakage of (Group A ) phosphoric-etching composite resin group were stronger than other groups P<.05. There were no significant difference between blood-contaminated groups(C,D and E groups) and uncontamined group(B group) P=.121. The Gingival microleakage was significant stronger than the incisal one P<.000. There were more microleakage between adhesive-bracket interface.Conclusion: SEP combined with RMGIC significantly decrease the microleakage campared with conventional phosphoric-etching combined with composite resin; The Gingival microleakage was significant stronger than the incisal one; Blood-contamination didn't effect the microleakage beneath brackets bonding with SEP and RMGIC. There were more microleakage between the adhesive-bracket interface than the enamel-adhesive interface.Total conclusion:1 The re-etching after blood contamination does not affect the bond strength of RMGIC;2 Etching for 30 seconds may adequate bond strengths for use;3 The blood contamination after etching decreased the bond strength of RGIC, but for contamination before SEP, the bond strength of RMGIC is not significant affected;4 SEP combined with RMGIC significantly decrease the microleakage campared with conventional phosphoric-etching combined with composite resin;5 The Gingival microleakage was significant stronger than the incisal one;6 Blood-contamination didn't effect the microleakage beneath brackets bonding with SEP and RMGIC;7 There were more microleakage between the adhesive-bracket interface than the enamel-adhesive interface.