As capability of the enamel surface to micromechanical adhesion with adhesives is not good enough to provide sufficient bond strength, enamel preparation is considered a necessary step before bonding [1]. With the development of the acid etching by Buonocore, enamel preparation by phosphoric acid is considered the most popular used method among orthodontists. Although this technique provides sufficient bond strength to resist orthodontic and masticatory forces [2], it is a multi-stage method and has many disadvantages, including enamel loss through etching [3], the need to dry the field during bonding [4] and the difficulty in removing the remnant resin after debonding [5].In the attempt to reduce phosphoric acid disadvantages and to simplify bonding procedure, different alternatives have been tested [6]. Selfetching primer SEP as a new system was introduced in order to move away from acid etching AbstractBackground. Self-etching primer and resin modified glass ionomer has been introduced to counter phosphoric etching disadvantages. Objectives. Evaluation of the bond failure rate of MBT stainless steel brackets bonded with either self etching primer SEP or resin modified glass ionomer RMGI in comparison with conventional methods CM. Material and Methods. 46 patients with complete permanent dentition were involved in this study. A total of 920 Gemini MBT ® brackets (3M Unitek, Monrovia, Calif) were bonded using a split-mouth design. For each patient, four adhesives systems were used: self etching primer SEP (Transbond Plus

Many theories have been proposed to explain adhesion mechanism between brackets and enamel surface. Chemical and mechanical adhesion are the main types [1]. Conventional bonding methods use phosphoric acid to prepare the enamel surface before bonding, increasing its capability to the adhesion by creating micro pores on the surface [2][3][4]. Although this technique increases bond strength, it is a multi stages method [5] and needs stern isolation procedures, as moisture weakens the bond strength [6]. Several studies were made to decrease the disadvantages of using phosphoric AbstractBackground. Many adhesive systems have been investigated as alternatives to conventional bonding methods. Selfetching primers and resin modified glass ionomer cement have been introduced to overcome the disadvantages of acid etching Objectives. To assess the effect of using either a self etching primer (SEP) or a resin modified glass ionomer (RMGI) on shear bond strength and failure type in comparison with conventional methods (CM). Material and Methods. Eighty metal brackets were bonded to buccal surfaces of human upper premolars by the same clinician according to 1of 4 protocols. Group 1, Transbond XT was used with self-etching primer (SEP) Transbond Plus (3M Untiek, Monrovia, Calif). Group 2, resin modified glass ionomer (RMGI) Fuji Ortho LC (GC Crop, Japan). Group 3, light cure resin (LC) Transbond XT (3M Unitek, Monrovia, Calif) were used with 37% phosphoric acid. Group 4, Chemically cure resin (CC) Unite (3M Unitek, Monrovia, Calif) were used with 37% phosphoric acid. The premolars were stored in distilled water for 24 hours at 4ºC. Brackets were loaded to failure in Instron machine. Descriptive statistics were calculated. ANOVA, Bonferroni, Kruskal-Wallis tests and MannWhitney U were used. Results. The present study indicated that the SEP provided no significantly higher shear bond (10.01 ± 5.46 MPa) than LC adhesive (8.59 ± 4.07 MPa) while RMGI showed the lowest (5.08 MPa). A comparison of the adhesive remnant index (ARI) scores indicated that there was significantly difference between the groups with less residual adhesive remaining on the teeth with SEP and RMGI. Conclusions. SEP produced bond strength clinically accepted with less amount of residual adhesive left on the enamel while RMGI produced unacceptable bond strength. SEP can use successfully in bond orthodontic brackets (Dent. Med. Probl. 2016, 53, 1, 50-55).