Titanium metal is one of the most widely used biomedical orthopedic materials because of its decent mechanical properties [1]. However, as an inert material, it cannot induce osteogenesis and has no antibacterial properties [2]. In order to improve surface bioactivity of titanium substrates, numerous methods have been proposed to cover it with bio-ceramic coatings [1]. Various clinical studies demonstrated that the hydroxyapatite coating of prosthesis can promote earlier osseous response which could increase the prosthesis fixation and the bonding strength [3,4,5].

Titanium implants are usually placed in contact with bones and gingival tissues so they are partially exposed to the oral cavity during and after implantation. This increases the hazard of bacterial infection, which is known as peri-implantitis [6, 7].

For centuries, Zinc (Zn) as one of the essential elements of tissues in the human body has a stimulating role in the metabolism of bones and has been used as bacteriostatic and bactericidal agents [8, 9]. Zinc can enhance the retention strength and osseointegration of implants [10, 11], by stimulating alkaline-phosphatase activity and collagen production, thus can increase bone deposition and reduce bone resorption [12]. Zn deficiency results in skeletal changes, including retardation of skeletal growth [10] and prolonged bone recovery [13]. Moreover, Zn species are also known to possess excellent antibacterial qualities. Zinc showed inhibitory effects against several bacteria, including Streptococcal mutans [14,15,16].

The metals’ antibacterial activity has been contingent on their contact surface; thus, a greater nanoparticles’ surface area permits larger interfaces and increases their interactions with other particles [17].

Although HA coatings revealed an enhanced bone attachment and thus better implants integration, long-term coating stability is quite a provoking concern [18]. Numerous coating techniques like plasma spraying, sol-gel, electrophoretic deposition, electro deposition have been employed to deposit hydroxyapatite on titanium implants. Plasma spraying is the most widely used technique for coating, but it leads to decomposition of HA due to the high temperature used, and it cannot be employed for complex structures. In electrophoretic deposition, high voltage was applied to the metal surface in order to attract the dispersed particles which leads to anodic polarization of metal substrate. This might increase the corrosion risk of metal and suppress the adhesion of HA particles [19,20,21]. Electro-chemical deposition (ED) is a frequently used approach with increasing popularity, due to variability of coating composition, process simplicity, and its applicability for multidimensional implant surfaces [22].