Resonance frequency analysis(RFA) has been successfully applied to measure the stability of implants, and proved to an objective method. Domestic and international scholars in the field of organ implantation have paid great attention on RFA in recent years. The present paper systematically introduces principles and applications of RFA in buccal medicine. The advantages and insufficiencies of RFA are discussed too.

Objective:Through the cases retrospective study, to analyze the correlation between the adjacent endodontic teeth and the retrograde implantitis. Methods: 32 patients were selected and there were 39 implants (ITI 28,MDIC 11), which adjacent teeth had received endodontic therapy. Record the time from endodontic therapy and the distance of the apex of implants to the adjacent tooth by X-ray photograph. Results: There were 10 implants with retrograde peri-implantitis of 39 implants. In 8 implants, their adjacent teeth received root canal therapy within 3 months(P

0.05). Conclude:The bone type may affect the stability of ITI osseointegrated implants.

Objective To investigate the clinical features of acute traumatic subdural hematomas (SDH) in infants and discuss the treatment methods. Methods The clinical features of 48 infants under three years old with acute traumatic SDH admitted from 2002 to 2008 were retrospectively analyzed.Results There were 31 infants under one year old (65%). The most popular injury cause was accidental fall in 37 patients (77%). Of all patients, 12 patients (25%) had disturbance of consciousness,eight ( 17% ) had convulsion and eight ( 17% ) were combined with skull fractures. The treatment methods included craniotomy and evacuation of the blood clot in 18 patients ( including 13 patients underwent instant operation after admission ), burr hole craniotomy and external drainage of the chronic subdural hematoma in seven and conservative management in 23 with small subdural hematomas. All patients obtained good outcome except that two patients had motor dysfunction and one death. Conclusions The incidence of acute traumatic SDH in infants is high, especially in infants under one year old. It is easy to be disregarded at early stage and may deteriorate to chronic subdural hematoma or hydropsy. Early diagnosis and active surgical treatment may attain sound prognosis.

Minimally invasive neurosurgery techniques developing by leaps and bounds in the past few years,which is to be a great challenge for the clinical teaching of neurosurgery.Based on their own actual,neurosurgery department of the Children's hospital of Chongqing medical university enriched the teaching contents,improved teaching methods and trained microsurgical techniques for doctors at various levels,meanwhile,it strengthened participants'sterile awareness,set good team spirit,developed individualized assessment standards and achieved good results.

Objective To study the guiding role of ultrasonography to the operation of spontaneous constriction of radial nerve.Methods Six patients with spontaneous constriction of radial nerve were checked by ultrasound before operation to identify the number,position and morphological change of the constriction lesions of the radial nerve.The result was compared with the operation result.Results According to the ultrasonography results,2 to 3 constriction lesions were found on the radial nerve of all the 6 patients.The ultrasonography description of the number,position and morphological change of the lesions was consistent with the operation result.After the operation,the radial nerve function of all the patients got recovered.Conclusions Ultrasonography examination before operation can identify the number,position and morphological change of the constriction lesions of the radial nerve,which has great value when planning the operation.

Objective To explore the clinical characteristics of posttraumatic cerebral massive infarction in children. Methods 68 cases were reviewed. Results There were 43 cases complicated with subarachnoid hemorrhage, 37 with brain contusion, 48 with fracture of skull,and the hematoma was subdural in 29 cases, epidural in 16 cases, and intracerebral in 14 cases. Other complications included fracture of limbs (24/68), thoracic or abdominal injury (15/68), and hemorrhagic shock (30/68). The infarction were found mostly in the first 7 d (range 2 h~13 d), and 32 cases within 4~7 d after the trauma. The outcome when discharged (according to the Glasgow outcome scale) was good recovery in 32 cases, moderate disability in 15 cases, severe disability in 9 cases, vegetative state in 4 cases, and 8 cases died. Conclusion The feature of the posttraumatic cerebral massive infarction in children is usually concealed by primary injury. CT and MRI are the bases for diagnosis.The outcome may be better than in the adults when early diagnosis and intervention has been produced.

Objective:To investigate the effects of repeated high acceleration(+Gz)on implant osseointegration in SD rats.Methods:18 SD rats were divided into+Gz and control groups randomly(n=9),and 1 implant was placed in each femur of the rat's lower limb.24 hours postoperatively,the experimental rats were exposed to+Gz of 4 to 9 G with 1 G/s environment 3 times a week,while the con-trol rats were fed normally.3 rats from each of the 2 groups were sacrificed at 2,4 and 8 weeks after implantation.Micro-CT,sequential fluorescence double labeling,and histological examination were perfomed for the analysis of implant osseointegration.Results:The bone volume fraction(BV/TV),trabecular number(Tb.N),mineral apposition rate(MAR),implant-bone contact rate(BIC)and bone area in implant thread(BA)of the+Gz group were significantly lower than those of the control group at 2 weeks(P＜0.05),and so as to MAR,BA at 4 weeks(P＜0.05),while there was no significant difference of the parameters at 8 weeks after implantation.Conclusion:In SD rats early exposure to+Gz environment postoperatively may have a negative effect on initial osseointegration by slowing bone forma-tion.However,it will not lead to poorer bone mass when sustained over a long period.