The Study Of NaOCl Act On Orthodontic Bonding Effect

Objective: In the procedure of orthodontic treatment, braces are indispensable materials. The movement of teeth is based on steadiness and long-act of braces'adherent. In order to increase the bonding strength of braces and prevent them from shedding researchers have always been done further study. Buonocore used phosphoric acid for pretreating teeth surface and found an effective ways for bonding organic resin to teeth enamel in the 1950s and until now. Roberto Justus made Clorox used to bonding of braces, injectioning new idea to the traditional bonding means. Based on these studies, this study will use solution of NaClO in orthodontic bonding of braces to improve bonding strength of braces, inhibit them from falling off.Methods: 60 vitro premolar teeth in need of orthodontics.Demand of the structure of teeth'surface is not decayed, and has no dysplasia of teeth enamel, no filler, no flaw and color's difference, the size of dental crowns is almost close and curvature of labial surface is as flat as possible. Embedding teeth in self-congealing base In Angle (45°), dental crowns is outside the base. Divide into six groups randomly, put the base and teeth in physiological saline under the preservation of -4℃. The first group (10 vitro premolar teeth) is bonding in common way, the Beijing-Tianjin enamel bonding agents are used with 37% acid solvent to etch for 1 minute, and then flushed by water mist for 15 seconds, the Beijing-Tianjin enamel bonding agents are bonding to premolar'braces; The second and third group are used with 2% solution of NaClO to remove protein respectively for 1 minute and 30 seconds, and then bonded to braces with the ordinary way after 30 seconds; The Fourth and fifth groups are used with 5% solution of NaClO to remove of protein respectively for 1 minute and 30 seconds, and then bonded to braces with the ordinary way after 30 seconds; The Sixth groups Trans - bond XT bonding agent is bonded to braces. Each sample bonding to braces is put into 0.9% physiological saline. And use microcomputer electronic tester examines the shear strength of each group. After debonding, the remains of bonding agents on the surface of enamel are evaluated with ARI.Scanning electron microscope examines the structure of teeth'surface on treatment of phosphoric acid and solution of NaClO.Results:1. Maximum load of each group are as follows: Group 1:243.63; Group 2: 193.95;Group 3 : 229.19;Group 4 :152.82;Group 5: 256.85;Group 6: 210.43. Use the software SPSS16.0 to analyze the differences by post hoc analysis. It shows that Group 5 is statistically significant.2. Scores of ARI have no significant differences (p > 0.05)(Table 3).3. Scanning electron microscope shows that scattered demineralized changes of the enamel surface is as a honeycomb. It is more flat and even on surface on treatment of solution of NaClO than on treatment of phosphoric acid.Conclusion:1. Before acid-etching, the bonding strength on treatment of solution of NaClO is greater than phosphoric acid.2. Before adherent to braces, use 5.25% solution of NaClO removing protein for 30 seconds to treat the surface of teeth, it can increase the bonding effect to braces.3. Before the acid-etching, with different espesor and time of treatment, the scores of ARI have no significant different.