Currently, dental implants are generally used for reconstruction of oromaxillofacial defects. Implants are widely used in dental and medical fields. The materials of implants are variable such as metals and ceramics. The materials of implants must be have not toxicity and biocompatibility to host and mechanical(physical) strength. Bones must be attached to titanium surface without any other tissues. many researcher's had studied for raising the osseointegration through various method which are including implants designs and materials. It was reported over 95% success ratio. many researcher's study the methods which are enhancing the speed of bone remodelling and osseointegration. Thermo dynamic therapy is one of the method to accelerlate the speed of bone remodelling and osseointegration. Thus it raise stability of implants. The purpose of this study was to evaluate the effect of diode laser irradiation for ossoeintegration in implant interface and between the implants threads. 24 New Zealand white rabbits which were about 3kg weight, used for experiment. 2 implant's were implanted every rabbit's tibia. 2 weeks, 4 weeks, 8 weeks after implantation, tissue sample were removed from sacrificed rabbit's tibia. 8 rabbit's were sacrificed every 2, 4, 8 weeks and undecalcified sample were made from tissue sample. We have investigated the undecalcified samples by back scattered electron microscope. We have analysied the length rate and area rate in implant interface and inside the threads. The results were as follows. 2 weeks, 4 weeks, 8 weeks experimental groups which were irradiated low level laser therapy showed rapid bone remodelling than control groups. It was suggested that Initial bone remodelling may be effected by LLLT because of implant bone contact ratio between 4th weeks and 8th weeks had no siginifant difference. Initial bone remodelling may be more influenced than later bone remodelling by LLLT because of new bone formation area ratio between implant threads had no significant differences during 4th to 8th weeks. According to above results, low level laser irradiation accerlate the new bone formation in implant interface and inside the implants threads at initial stage. there were many factors which are increasing the bone remodelling, because there were many differences between experimental and control groups. Low level laser irradiation were helpful for increasing the initial stage of bone remodelling because of above results.

Demineralized Freeze Dried Bone(DFDB) graft material have been used for reconstruction of large bony defects or augmentation of thin alveolar ridge during implantation of titanium fixtures. But at present osteogenic effect of DFDB do not overcome the capacity of autogenic bone graft. Thus many investigators had applicated various bioactive substance to DFDB to enhance the ability of osteogenesis of DFDB. In this study, mixture of grafting material was made from fibrin glue(F) and DFDB(D)(group 1: F+D), fibrin glue, DFDB and rhBMP-2(B) (group 2: F+D+B), fibrin glue, DFDB, polylactic- co-glycolic acid(PLGA)(P) and rhBMP-2(goup 3: F+D+B+P), fibrin glue, DFDB, PLGA, rhBMP-2 and autogenic osteoblasts( O)(group 4: F+D+B+P+O), and fibrin glue, DFDB, autogenic osteoblasts (group 5: F+D+O). During first surgical procedure, extraction of molar teeth was performed at male Biggle dog's mandible, and collected bone marrow tissue from tibia at same Biggle dog. Collected bone marrow tissue was cultured and differentiated into osteoblasts in vitro, and stored in nitrogen bottle. After four months, titanium fixture was implanted with prepared graft material to Biggle dog's mandible. After four and eight weeks respectively, experimental dog was sacrificed. Obtained tissues were prepared for examination by using resin embedded ground section method. Prepared sections were evaluated with transmitted and polarized microscope, and areas of osteoid and cacified bone were calculated with IPTK 5.0( image processing tool kit version 5.0). Resultant data was statistically analyzed by SPSS 13.0 software. Results of this study showed that autogenic osteoblats had more enhancing capacity of bone formation than rhBMP-2, but PLGA inhibited bone forming potential of bony tissue.

The diffe rentiation of osteoblasts from mesenchymal precursors requires a series of cell fa te decis ions controlled by a hi erarchy of transcription factors Among these are RUNX2, osterix (OSX) , ATF4 and a la rge number of nuclear co-regulators. During bone development, initial RUNX2 expression coincides with the formation of mesenchyma l con densations well before the branching of chondrogenic and osteogenic lineages. Runx2 is s ubject to a number 0 1' post - tran scriptional controls including regulation by nuclear accessory factors such as ATF4 and DLX5 and post-trans lational mod ificati on, especially phosphOl‘ylation. We previously showed that Runx2-dependent transcription is acti vated by the ex tracellular signal-regulated/MAP kinase pathway in response to ECM/integrin and FGF2 stimulation. To identify and a5sess the function of ERK/MAPK phosphorylation s ites in RUNX2 and esta bli sh the role of MAPK s ignaling in bone fo 1'mation Approaches: A deletion/mutagenesis approach wa5 used to ide ntify 1'egions 0 1' RUNX2 necessary fo1' MAPK responsiveness and phosphorylation. To evaluate the in vivo function of the ERK/MAPK pa thway‘ transgen ic mice were developed wi th osteoblast- specific expression of either dominant-negative 0 1' cons titutively-active MEKl in osteoblasts and crossed with Runx2 heterozygous-• null ammals RUNX2 is phosphorylated on two critical serine res idues in the P/S/T domain. RUNX2 conta ining S/A mutations in these sites is refractory to MAPK stimula ti on while S/E muta tions cause cons titutive activation MAPK activation of RUNX2 was also found to occur in vivo 까'a n sge ni c expression of cons titutively ac tive MEKl in osteo • blas ts accelerated skeletal development while a dominant-negati ve MEKl reta rd ed bone formation in a RUNX2- dependent manner As shown by these studies‘ the ERK/MAPK pathway controls Runx2 tra nscript iona l activ ity by phosphorylation at specific serine residues. This may be a major pathway for controlling osteoblast activity in response to extracellul ar matrix signals. mechanical loads and hormonal stimulation

μ방lt emitting diodes (LED) devices are commercially introduced as an alternative for low-Ievellaser therapy (11ι，T) ， and it has several advantages over lasers such as a safe, efficient, and less-expensive altemative to treat wounds. And LED irradiation at the same biostimulatory wavelength has similar bíochemical effεαs. In the present study, to asses whether the I핑ht-emitting diode (LED) irradíation can stimulate bone regeneration, irradiated bony defects with or without grafting materials on rat calvaria were compared to corresponding nonirradiated control. Fifty male Sprague-Dawly rats weighing about 150g, were used. Factors for present study were designed as follows, 1) presence or absence of grafting materials, 2) with or without irradiation, and 3) number of irradiation. Two weeks after operation, rats were sacrifìced. Radiologic and 비stomorphologic fmdings were evaluated. Macrospically, there were no incidents of infection, dehiscence, hematoma and necrosis during study. Radiological findings showed greater radiopacity in the graft group and radiopacity increased as the number of irradiation increase. And microscopically, new bαle formation was great in the graft group and increased as the number of irradiation increase, Present study has shown that LED irradiation improved bone regeneration through radiologic and histomorphologic fmdings in rat.

The purpose of this study was to research the osseointegration in the interface of dental gold alloy. Some investigator presented that gold was biologically safe but occurred fibrous integration on implant interface. We used 4 different gold composition implant to investigate the osseointegration on implant interface. Osseointegration occurred on the all implant interface. We thought that osseointegration depended not only on gold composition but also on precious metal composition such as platinum or silver. If we use precious metal implant, it might reduce the Galvanic current and chemical corrosion which were occurred between titanium implant and percious metal suprastructure. We recommend that precious metal implant was superior to non-precious metal implant without financial problem.

Hydroxyapatite(HA) has been widely used as bone substitutes to rehabilitate bone loss area by new bone formation. But there were some problem of bone formation around HAs due to a little space between HAs embedded in bone loss area. The purpose of this study was to observe morphologically new bone formation around HAs mixed with PLGA block (5.5㎜ in diameter, 4 mm in depth) in Newzealand white rabbit tibia. Before 1 week of sacrification, Alizarin red was injected intraperitoneally into rabbit. At 3 day, 1, 2, 4, 10, 18, 32 weeks, bones with HA as control group(CG)and HA mixed with PLGA block as experimental group (EG)were fixed with 10 % neutral formalin, dehydrated, and embedded with Spurr low viscosity resin. After the specimens were cut by 500 ㎛ with slow diamond wheel saw, these were coated with carbon and examined by REM, LSM and qualifative analysis of calcium and phosphorous deposition were done with EPMA. The obtained results were as follows. 1. Both group showed scattered HA around compact bone under REM and little AZ labelled bone under LSM at 3 days. 2. Both group showed active AZ labelled bone, while EG showed higher Ca(calcium) and P(phosphate) deposition than that of CG at 1 wk. 3. There was decreased AZ labelled bone of both group under LSM. REM of EG showed HA associated with new bone from compact bone, while EPMA features showed similar to Ca and P deposition at 1 wk and EG showed higher than that of CG. 4. REM features of both group showed resorbed HA associated with new bone. There was decreased AZ labelled bone of both group under LSM. EPMA features showed higher Ca and P deposition at 4 wks than that of 2 wks. 5. New bone of both group was well demarcated from compact bone under REM at 10 wks. LSM features showed various AZ labelled bone, but weak AZ labelled than that of CG. 6. LSM features of 14 wks showed discontinuous AZ labelled on osteon formation. EPMA of both group showed increased Ca deposition, while there was higher Ca deposition of EG and similar P deposition to CG. 7. REM featureless of 18 wks in EG showed similar gray color to compact bone. LSM features showed osteon formation with little concentric lamellars. EPMA of both group showed increased Ca deposition, while there was higher Ca and P deposition of EG. 8. New bone was ill demarcated from compact bone and increased otseon formation of REM features at 32 wks. There was little AZ labelled bone. EPMA features showed higher Ca and P deposition of EG than that of compact bone. From the aboving results, there was early active AZ labelled bone of both group within 1-2 weeks and since 18 weeks new bone with active osteon formation was poorly demarcated from compact bone. Calcium deposition of EG was early increased than that of CG deposition since 4 weeks after experiments. It was suggested that EG showed active and rapid new bone formation and similar bone mineralization of compact bone