The Influence of Storage in Saline or Irradiation by Ultraviolet on Implant Hydrophilicity and Osseointegration: An Experimental Study in Rabbits

Abstract

Storage in aqueous solution or ultraviolet (UV) irradiation  can  re t ain or regain the hydrophilicity of titanium implant surface.  In this study, t hree types of commercial titanium implants were used : ZBL (ZDI Bone  L evel ® ), CEL (C-tech Esthetic Line ® ) , and modSLA (Straumann SLActive ® ). ZBL and CEL implants were treated with UV irradiation for 4 h. Surface characterization of the four groups (ZBL, ZBL-UV, CEL-UV, modSLA)  was  evaluated by scanning electron microscopy and contact angle measurements. The  in vivo bone response  was  evaluated by removal torque (RTQ) tests and histomorphometric analysis  at  3, 6 , and 12 weeks post-implantation. A total of 144 implants and 36 rabbits were used for experiments according to a previously established randomization sequence. The  ZBL-UV, CEL-UV , andmodSLA groups were hydrophilic, and nanostructures were observed on  the  modSLA implant surface.ModSLA achieved better  RTQ value than ZBL at 12 weeks ( p <0.05). For histomorphometric analysis, ZBL-UV and CEL-UV implants showed higher bone area values in  the  cancellous bone zone at 6 weeks than  did  modSLA and ZBL  implants  ( p <0.05).In  the  cortical bone zone, all groups showed comparable bone-to-implant contact at all healing time points ( p >0.05).Both storage in saline  and UV irradiation could retain or provoke hydr o philic surfaces and improve osseointegration. Compared to storage in saline, UV irradiation displayed slight advantages in promoting new bone formation in cancellous bone zone at  an  early stage.