A Study On Osseointegration Of Titanium Implants In Irradiated Dog Mandibles And Its Improvements

The maxillofacial rehabilitation of patients after treatment formalignancy of the head and neck is a clinical cballenge. Although theobturator is the main way of conventional prothesees at present, the lack ofretention and stabilization makes the soft tissue undertake much more pressure.Applying endosseous implant can improve the retention of the obturator.Irradiation before or after surgery retards the bone regeneration and increasesthe probability of failure when applying the endsseous implants in irradiatedbone. Weile in the past, the patients who had received irradiation on the headand neck were excluded from lmplant reconsturction, the irradiation to theimplant site is not the absolute contraincation now. Although most authoritiesconsider that irradiation to the jaws is not an absofute cotraindication,thereare many questions we should think about.HBO (hyperbaric oxygen) is considerd as a definitive cure method forORN by many practitionere. It is also considered as an important means toimprove the osseointegration of the detal lmplants inserted in irradiated bone.Many materiais, including some kinds of biologic factors, were used toreconstruct defects in irradiated tissue bed. Most of them,such as BMP,broughgood effect. Few reports regarding the application of the factors in theosseointegration of the dental implants in irradiated jaws can be found.Wnan is inVeSgated as a vehicle for high molecular weght drugsgiVen SUbCUtanQUSly It can reod the release of drugS. In thes eXPeriemwtthe M of using the for of thBMP-2 and hyaiurnan on osseointegrathaofthaUm mpants in edated dog mandiles was tad.Pot I: Tke effeot ofradibo on o88eOintegratinofbolant8ObN: l) To StUdy the M M of the dog Inandibe aftendatiOn; 2)To StUdy the osseointegration of thaUIn ~lants in allddOg mandibes.Mwt andMdsode: Four mai adul dogS,wh an aVerag weightof abOat 20-22kg underWed ndon of the Inandile ch. fourth Premolarand first molar tO creat6 ebo regions. Thre months ds healing, oneside of the Mle of each dog was ndated wh a single 15-Gy dOse. Theother sthe served as control. the months ds ds, fOur thaUmmpants were W in each mandile. Two of theIn wer Placed wtth thewt of rhBMP-2 and W The dOgS were sWced at 1.5 and 3months ds bolant insthed. The bone denSity(BMD) of the M1e. thebone contact wte ratioraCSR). the specilic trabecular bone volum0VsP).bone nilnMn rate and the intensity of BMP arOUn twlant wered.ReSde 1) BMD was foWer in the edated side than in the nOWatedaide. The bo bbeen tWo sides was larger in 6-month grouP dsch than in 4.5-mOnth grouP. 2) BCSR of twlants in edated sideswas ed~ lower bo in nortated siaes (pe0.0001 <0.01 ). 3 ) ffeqUantw of the trforcular bone arOUn linPhas in edated sides was notwificantly fowr than in nobod sides (Ped.071 >0.05 ). 4) Inl.5conth and 3wt grouPs, bone Won nd was nO Obviouslydibo betWee the ndated dss and the chd tas.Conclwt: l) Radiedon diwtd the bon regWon, deCreased thebone M 2) BCSR ofbolants wtase ds Wn.Part n: The effert ofhrperbaric oxygen aduncthre hetheot onosseointegrthen of titaulIUn bolant8 in dsd dog manewle8ObN: To evaiUate the effeCt of hyPerbaric OXyen adjunctiVetrebe on osseointegration oftithaUm twlants in edated dog mandiles.M and Mode: Four W adul dogs wt an aVerage weghtof about 20-22kg undwt extraction of the Mle dri. fond Premlarand for mo1ar tO Create edentulous regions. Thre month ds healing oneside of the Mle Of eaCh dOg was chd the a singl l5-Gy dose. Theother sthe servd as COntrl. M W twO mOnths, the dOgs recehed theadjunctive hyPertredc oxvenpeO) theranr berore ana de bolantsinsenion. The othe grOU did no .The followin PrOcedurs wer the same asPat I.Resuto l) BMD was foWer in the chd side than in the nondatedside. The We bben two sides was lopr in 6-month grOU dstwation than in 4.5wt grouP. ms Phenmenn was no obvious dsHBO adjunctire haInen. 2) Ther is no obivious Chang of...