Papers by Author: J.H. Chung

Abstract: The purpose of treatment for peri-implantitis is to achieve structural and functional restoration of the lost supporting tissues around implants, including re-osseointegration. Both surgical and non-surgical approaches in combination with a variety of anti-microbial treatment regimens have been applied depending on the size and shape of the bone defect. Tetracycline-HCl (Tc) treatment has been considered as a effective chemical modality for decontamination and detoxification of contaminated implant surfaces. The aim of this study was to examine if Tc conditioning changes the microstructures of the modified surface of dental implants. Dental implants with (1) hydroxyapatite-coated surface (HAS) (Replace® select HA, Nobel Biocare AB, Göthenburg, Sweden), (2) TiO2-blasted surface (TBS) (Astra TiOblast®, ASTRA Tech AB, Mölndal, Sweden) were used in this study. Tc treatment noticeably altered the surface of HAS and TBS. HAS and TBS were partially removed from the implant surface as early as 90 and 60 sec, respectively.

Abstract: The increased surface roughness of dental implants has shown enhanced integration of bone tissues to implant surfaces, but may be predisposed to an increased risk of pathogenic bacterial infection and contamination with bacterial products. Tetracycline-HCl (Tc) treatment has been regarded as a practical and effective chemical modality for decontamination and detoxification of contaminated implant surfaces. The purpose of this study was to examine if Tc treatment alters the microstructures of the modified surface of dental implants. For this purpose, dental implants with pure titanium machined surface (MS), sandblasted, large grit, acid-etched surface (SLAS), or anodized surface (AS) were used. The surface of dental implants was rubbed for 30, 60, 90, 120, or 150 sec with sponge pellets soaked in Tc solution (50mg/ml) and in distilled water for 0 and 150 sec as the control group. The specimens were then routinely processed for scanning electron microscopy. The results show that Tc treatment did not change the surface of MS, SLAS, and AS.

Abstract: The purpose of this study was to examine if the application of titanium-reinforced expanded polytetrafluoroethylene(TR-ePTFE) membrane combined with bovine bone mineral(BBM) soaked in inorganic polyphosphate promotes exophytic bone formation in rabbit calvaria. For this purpose, a total of 8 rabbits were used, and rectangular decorticated calvaria sites were created using a round carbide bur. In the control group, rectangular parallelepiped-shaped TR-ePTFE membranes (RPTPMs) were filled with BBM soaked in saline and placed on the decorticated sites and fixed with metal pins. In the experimental groups, RPTPMs were filled with BBM soaked in 4%, 8% and 16% inorganic polyphosphate prior to fixing with metal pins. Animals were sacrificed at 4 and 8 weeks after surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. The results indicated that at 8 weeks, all the experimental groups demonstrated exophytic bone formation. At 8 weeks, the 8% polyphosphate group revealed the most new bone formation (p<0.05). On the basis of these findings, we conclude that inorganic polyphosphate has a promoting effect on bone regeneration, possibly by enhancing osteoinductivity of the decorticated wound area and osteoconductivity of the carrier material, but not much as we expected.

Abstract: The purpose of this study was to examine if the application of custom-made porous titanium membranes combined with bone graft materials promotes exophytic bone formation in rabbit calvaria. For this purpose, round decorticated calvaria sites were created using a round carbide bur. In the control group, rectangular parallelepiped-shaped porous titanium membranes (RPTMs) were placed on the decorticated sites and fixed with metal pins. In the experimental groups, RPTMs were filled with one of the following bone graft materials prior to fixing with metal pins: bovine bone mineral (BBM), demineralized freeze-dried human cortical bone (DFDB) or freeze-dried human cancellous bone (FDB). Animals were sacrificed at 8 and 12 weeks after surgery, and new bone formation was assessed by histomorphometric as well as statistical analysis. The results indicate that at 8 and 12 weeks, all the experimental groups demonstrated exophytic bone formation. At 12 weeks, DFDB group revealed the most new bone formation (p<0.05) and resorption of grafted materials (p<0.05). On the basis of these findings, we conclude that RPTMs may be used as an augmentation membrane for guided bone regeneration and DFDB as an effective bone-inducing graft material.