Incorporation of amorphous calcium phosphate (ACP) into glass ionomer cement: influence on microleakage of cemented orthodontic bands. Maryam Omidkhoda 1 , Farzin Heravi 2 , Shideh Gharaei 3 , Abdolrasoul Rangrazi 4* , Tabassom Hooshmand 5 1 Associate Professor of Orthodontics, Dental Materials Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran 2 Professor of Orthodontics, Dental Materials Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran 3 School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran 4 Dental Research Center, School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran 5 Associate Professor of Dental Materials, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran Abstract Aim: With regard to the anticariogenic and remineralizing properties of ACP, the aim of this study was to compare the microleakage of conventional glass ionomer and ACP containing glass ionomer cements under orthodontic bands. Materials and methods: Sixty extracted first maxillary premolars were randomly divided into 2 groups. In the group A, the teeth were cemented by conventional glass ionomer cement and in the group B they were cemented by ACP containing glass ionomer cement. Then samples subjected to thermocycling. A dye penetration method was used for microleakage evaluation. Microleakage was determined with a stereomicroscope for the cement-band and cement-enamel interfaces from the buccal and lingual sides at the occlusal and gingival margins. Results: Post hoc comparisons showed amount of microleakage in the control group was significantly higher than experimental group in cement-enamel interface at bucco-gingival level (p-value=0.01). No significant difference between control and experimental groups was observed in other areas. Conclusion: ACP containing glass ionomer causes less microleakage than conventional glass ionomer in enamel-cement interface. However there was no significant difference in microleakage between ACP containing GI and conventional GI in most of area. Therefore ACP-containing GI can be used in orthodontic banding. Keywords: Amorphous calcium phosphate, Microleakage, Orthodontic bands. Accepted on June 08, 2016 Introduction Anchorage from the posterior teeth is essential to hold and guide other teeth in the arch in an orthodontic treatment [1]. A firm attachment such as orthodontic band provides this anchorage. One of the most common disadvantages of orthodontic bands is enamel demineralization because tooth cleaning is more difficult in this area due to their posterior position in the mouth, resulting in accumulation of plaque and consequently white spot lesions [2,3]. Zinc phosphate, zinc polycarboxylate, conventional glass ionomer cement (GIC), resin modified GIC and Acid modified composite resins are commonly used for bands cementation [4]. Glass Ionomer Cements (GIC) became popular in dentistry because of their chemical adhesion, fluoride release, low thermal coefficient of expansion almost near the tooth and their biocompatibility [5]. Several studies have been attempted to improve the antibacterial or mechanical properties of GIC by adding different materials such as bioactive ceramic particles, glass powders and other chemicals to the GIC [6-11]. In recent years modification of glass ionomer cement with remineralizer materials such as amorphous calcium phosphate products is conducted as a one way to overcome on demineralization [12]. Amorphous calcium phosphate at the tooth surface caused to maintain a state of saturation of calcium and phosphate ions and thereby reimneralization of tooth [13,14]. With respect to the ability of ACP in tooth remineralization, it could be added to GIC in orthodontic band cementation which in turn reduces ISSN 0970-938X www.biomedres.info Biomed Res- India 2017 Volume 28 Issue 2 Biomedical Research 2017; 28 (2): 616-619 616