RESUMO
Objective To confirm the sensitivity and validity of near-infrared spectroscopy (NIRS) technology to detect the dynamic changes of blood volume and regional tissue oxygen saturation (rSO2).Methods Six fibular flaps on Rhesus monkeys were raised simulating a clinical operation.Third generation of NIRS oxygen saturation oximeter (TSAH-100) was employed on Rhesus monkeys' fibular flaps when its dominant artery and vein were blocked respectively or simultaneously,and then their relative changes of blood volume and oxygen saturation were observed and recorded in June,2008 to October,2008.Results The statistic results showed that concentration of deoxygenated hemoglobin (cHb),concentration of oxyhe moglobin (cHbO2) and rSO2 had rapid,apparent and distinct changes respectively in the case of arterial occlusion,venous occlusion and total occlusion.The initial values of cHb and cHbO2 of 3 models were 0 μmol/L.Meanwhile,the initial values of rSO2 in artery embolism,vein embolism and arteriovenous embolism were 51.6％,54.3％ and 56.8％,respectively.The maximum variations of cHb,cHbO2 and rSO2 in 3 models indicated significant difference compared with initial values (P＜0.05),the values of rSO2 after 6 s,18 s and 8 s in 3 models had significant difference compared with initial values respectively(P＜0.05).Conclusion The TSAH-100 based on NIRS technology is an extraordinarily sensitive and reliable method to monitor the changes of oxygen saturation and blood perfusion in local tissue for buried flap within a depth of 2.0 cm.
RESUMO
Objective:To introduce a novel ridge preservation technique with micro-titanium plate avoiding the use of bone grafting materials,and evaluate the potential horizontal bone preservation effect of this new technique,applied on single maxillary central incisors after tooth extraction for future implant restoration.Methods:Nine patients (six women and three men),mean age (26.0 ±5.7)years(from 1 8 to 34 years)referred to the Department of Oral Implantology,Peking University School and Hospital of Stomotology,were selected and diagnosed with unsalvageable single middle incisor with fine general con-ditions,no signs of acute local inflammation,no ongoing or previous periodontitis,healthy neighboring teeth and intact buccal bone walls.Tooth extraction,delayed implant placement and implant-supported single crown restoration were selected as treatment plan.The teeth were extracted atraumatically with lo-cal anesthesia,followed by a reflection of a minor flap to exposed 2-3 mm of the buccal bone plate.Af-ter that,a micro-titanium plate was trimmed and bended to fit the convexity of the labial bone and fixed by two mini pins with intent to support the labial soft tissue.The flap was then repositioned over the micro titanium plate and secured with two single sutures.No bone grafting materials or releasing incisions were needed.The sockets were left to heal without any intention of primary wound closure.Cone-beam compu-ted tomographic (CBCT)scans were obtained before and four months after tooth extraction.Horizontal ridge widths were measured with CBCT software,and the preservation effects were calculated and recor-ded by the percentage of horizontal ridge alteration.Results:The nine extraction sockets were healed un-eventfully.The average socket width before extraction was (7.51 ±0.48)mm (6.92-7.82 mm).The average alveolar ridge labial-palatal width at the control point of the edentulous area was (6.81 ±0.44) mm (6.04-7.38 mm)4 months after tooth extraction,the mean percentage of ridge width preserved was 90.87%±2.91%(87.28%-95.60%).Conclusion:This novel ridge preservation method by the usage of a micro-titanium plate did not interfere with the natural socket healing process,and at the same time,largely preserved the width of alveolar ridge without any bone grafting procedures.Long term results remain to be seen.