Background
CaP-coated implants are used to improve initial fixation in poor bone quality these days. It is reported that when CaP is coated on the surface of SLA implants, it improves the biocompatibility of the implant due to its similarity to the bone, and promotes the formation of new bone at the early stage of implant y enhancing the adhesion at the interface between bone and epithelium. The CaP coating method has been used in many ways such as plasma-spraying and ion application methods. However, due to nonuniformity, the ion-beam-assisted deposition(IABD) method is mainly used recently. It is known that the IABD does not damage the implant surface. Therefore, it is possible to maintain the characteristics of SLA surface and to expect better results on CaP coated SLA surface.
Aim/Hypothesis
The aim of this randomized controlled trial was to compare peri-implant marginal bone level around SLA surface and CaP coated SLA surface implants for initial one year.
Material and methods
A total of 34 patients were enrolled in a clinical study at a single institute of the Department of Periodontology, College of Dentistry, Yonsei University, Seoul, Rep. of Korea(Approval no. 2-2015-0038). The inclusion criteria are as follows; 1) Those 20 years of age or older, 2) Those who have an edentulous area and need implantation, 3) Nonsmokers or smokers less than 10 times a day. 
The allocation of subjects was made through a double blind method. Implant surgery procedures were followed by the manufacturer's guidelines. Clinical observations were performed immediately after implant placement, re-entry at 3 months, and 3,12 months f / u. The final prosthesis was loaded 4 months after implant placement. 
 Based on the clinical and radiological examinations, marginal bone change was evaluated one year after implant placement. Radiographs are taken immediately after implant placement, at re-entry, delivery of the final prosthesis, and 1 y f / u. The distance from the implant shoulder to the bone to implant contact (BIC) was defined as the marginal bone level and the annual change was defined as the marginal bone change. The unpaired t-test was used statistically.
Results
There was no failed implant, and most implants showed less than 1 mm of marginal bone loss. At 1year f/u, clinical examination revealed that the implants and surrounding structures were well maintained without adverse events.  Limited bone level alteration were noted at all sites of control and experimental groups, there was no clinically significant difference in the change of marginal bone.
Conclusions
Both CaP coated SLA and conventional SLA surface implants showed comparably successful marginal bone stability without any complications for initial one year.

Randomized controlled clinical trial for comparison of peri-implant marginal bone level around SLA and CaP coated SLA surface implants