Another PhD from the department!

Xing Rui has publicly defended her dissertation and been awarded the PhD-title

Thesis summary

Dental implant has become a popular solution to restore tooth functions. However, peri-implant diseases, such as peri-implant mucositis, pose serious clinical challenges to the long-term success of dental implant. Poor soft tissue integration onto the abutment increases the risk of bacterial infection and has an impact on the occurrence of peri-implant mucositis. In addition, soft tissue around the abutment is very fragile and lax after surgery, increasing the risk of bacterial infection and tissue inflammation. In order to achieve optimal soft tissue sealing around the abutment, this study has been focused on surface modification of abutment materials and was carried out through two strategies.

The first strategy was to modify the topography and chemistry of abutment surface for the purpose of promoting soft tissue attachment without increasing bacterial adhesion. Microgrooved surfaces were shown to possess the optimal surface texture for human gingival fibroblast (HGF) growth and harbored equally few bacteria as polished surfaces. Surfaces treated by cathodic polarization were incorporated with hydrogen. Hydrogen incorporation promoted the attachment and proliferation of HGF while at the meantime not affecting bacterial growth. Therefore, the combination of machining and cathodic polarization may be a promising new surface modification approach to enhance connective tissue growth without increasing the risk of infection, and hence holds the potential to improve the soft tissue sealing around the abutment.

The second strategy was to coat abutment surface with antimicrobial molecules to increase its infection resistance. Doxycycline (Doxy) has been demonstrated to be coated onto abutment surfaces after cathodic polarization. The coated surface has shown both an initial burst release and long-term retention of Doxy. The initial bacterial accumulation was significantly reduced on Doxy-coated surface. Thus, Doxy coating by cathodic polarization may contribute to reducing transmucosal complications, hence the occurrence of peri-implantitis and implant loss.


  • Reader, dr. Nikolaj Gadegaard, University of Glasgow
  • Professor, dr. Vidar Bakken, University of Bergen
  • Professor, dr.odont. Fernanda Cristina Petersen, University of Oslo


Tags: Xing Rui, Biomaterials
Published Nov. 11, 2014 2:15 PM - Last modified Apr. 7, 2017 10:41 AM