RESUMO
In our previous studies,a novel cortex-like TiO2 coating was prepared on Ti surface through micro-arc oxidation (MAO) by using sodium tetraborate as electrolyte,and the effects of the coating on cell attachment were testified.This study aimed to investigate the effects of this cortex-like MAO coating on osseointegration.A sand-blasting and acid-etching (SLA) coating that has been widely used in clinical practice served as control.Topographical and chemical characterizations were conducted by scanning electron microscopy,energy dispersive X-ray spectrometer,X-ray diffraction,contact angle meter,and step profiler.Results showed that the cortex-like coating had microslots and nanopores and it was superhydrophilic,whereas the SLA surface was hydrophobic.The roughness of MAO was similar to that of SLA.The MAO and SLA implants were implanted into the femoral condyles of New Zealand rabbits to evaluate their in-vivo performance through micro-CT,histological analysis,and fluorescent labeling at the bone-implant interface four weeks after surgery.The micro-CT showed that the bone volume ratio and mean trabecular thickness were similar between MAO and SLA groups four weeks after implantation.Histological analysis and fluorescent labeling showed no significant differences in the bone-implant contact between the MAO and SLA surfaces.It was suggested that with micro/nanostructure and superhydrophilicity,the cortex-like MAO coating causes excellent osseointegration,holding a promise of an application to implant modification.
RESUMO
The exposing of dental implant into the maxillary sinus combined with membrane perforation might increase risks of implant failure and sinus complications. Objective: The purpose of this study was to investigate the effects of the dental implant penetration into the maxillary sinus cavity in different depths on osseointegration and sinus health in a dog model. Material and Methods: Sixteen titanium implants were placed in the bilateral maxillary molar areas of eight adult mongrel dogs, which were randomly divided into four groups according to the different penetrating extents of implants into the sinus cavities (group A: 0 mm; group B: 1 mm; group C: 2 mm; group D: 3 mm). The block biopsies were harvested five months after surgery and evaluated by radiographic observation and histological analysis. Results: No signs of inflammatory reactions were observed in any maxillary sinus of the eight dogs. The tips of the implants with penetrating depth of 1 mm and 2 mm were found to be fully covered with newly formed membrane and partially with new bone. The tips of the implants with penetrating depth over 3 mm were exposed in the sinus cavity and showed no membrane or bone coverage. No significant differences were found among groups regarding implant stability, bone-to-implant contact (BIC) and bone area in the implant threads (BA). Conclusions: Despite the protrusion extents, penetration of dental implant into the maxillary sinus with membrane perforation does not compromise the sinus health and the implant osseointegration in canine. .