Objective:To investigate the effect of local application of bisphosphonates(BPs) and systemic estrogen replacement therapy on the osseointergration of hydroxyapatite-coated implant in ovariectomized rats.Methods:12 weeks after ovariectomiy,each of the 20 female rats accepted 2 hydroxyapatite-coated implant screws in proximal tibiae,with and without immobilized BPs respectively on 2 sides.Half of the animals received subcutaneous injections of 17β-estradiol(E).Thus,there were 4 groups:control,estrogen (E),BPs and E + BPs.Tibiae with the implant screws were examined by μ-CT and push-out test was performed 12 weeks after implantation.Results:The bone volume ratio around screws and the percentage osteointegration in E + BPs group increased by 2.3-fold and 1.9-fold,and the push-out force by 3.3-fold respectively,compared to untreated controls.In group E the fixation of screws was also increased but less than that in group E + BPs.Conclusion:Systemic estrogen replacement therapy and locally immobilized BPs have additive effects on osseointergration of hydroxyapatite-coated implant screws in ovariectomized rats.

Objective:To investigate the effect of degassing and peroxidation on metal-ceramic bonding strength of Pd-Ag alloy. Methods:The metal-ceramic interface of group A (peroxidation)and B (degassing)was investigated under scanning electronic micro-scope(SEM)and energy dispersive spectrum (EDS).The bond strength between metal and ceramics was measured using a three-point bend test according to ISO9693.Results:The formation of nodules on the surface of alloy specimens was observed in both groups by SEM.The nodules on the specimens of group A were more densely than those of group B.The diameter of nodules in group B was 1 .5μm approximately.The interface of the metal-ceramic specimens had a clear transition porcelain layer and no hole or slit was present. The mean bonding strength of group A and B was (45.97 ±3.92)MPa and (49.1 1 ±6.42)MPa respectively(P=0.031 ).Conclu-sion:Degassing can improve metal-ceramic bonding strength of Pd-Ag alloy significantly.

Objective: To investigate the proportion and role of CD45+ erythroid progenitor cells (EPC) in patients with tongue cancer metastasis. Methods: The initial treatment of tongue cancer patients (n=40) from January 2017 to June 2018 in He'nan Provincial People′s Hospital was included in this study. According to the presence or absence of lymph node metastasis, they were divided into tumor group (no lymph node metastasis was found in imaging and pathology) and metastasis group (both imaging and pathology confirmed lymph node metastasis). The expression of Ki-67 was detected by immunohistochemistry and the proportion of CD45+CD71+TER119+EPC was detected by flow cytometry. EPC was sorted by flow cytometry, interleukin-10 (IL-10) and transforming growth factor-β (TGF-β) were detected by enzyme-linked immunosorbent assay (ELISA), and reactive oxygen species (ROS) was detected by flow cytometry. Transwell was used for tumor invasion test; methyl thiazolyltetrazolium (MTT) assay was used to detect proliferation level. Results: There were 20 cases in the tumor group and metastasis group. There was no significant difference between the two groups in terms of age, sex, time of onset and size of tumors. Flow cytometry showed that the ratio of CD45+EPC in peripheral blood of tumor group and metastasis group was (1.2±0.2)% and (3.1±0.2)% (t=7.823, P<0.001). Correlation analysis showed that the ratio of CD45+EPC was positively correlated with the proliferation index of Ki-67 cells (r=0.592, P=0.006). The results of flow cytometry showed that the mean fluorescence intensity (MFI) of ROS in EPC was 102.1±22.9 in tumor group and 530.0±67.2 in metastasis group (t=6.025,P<0.001). The results of ELISA showed that the mass concentrations of IL-10 and TGF-β in EPC supernatant of tumor group were (10.8±1.6) and (3.2±0.8) μg/L, respectively. The mass concentrations of IL-10 and TGF-beta in EPC supernatant of metastasis group were (26.9±3.7) and (6.4±0.9) μg/L, respectively (t=3.956, P=0.003; t=2.595, P=0.027). Transwell results showed that the proportion of invasive cells in the CD45+EPC group [(40.3±4.4)%] was higher than that in the control group [(17.5±2.2)%] (t=4.607, P=0.001). MTT proliferation experiment showed that the proliferation rate of the CD45+EPC group [(52.0±3.3)%] was higher than that of the control group [(30.5±1.9)%] (t=5.656, P<0.001). Conclusions The proportion of CD45+EPC in patients with tongue cancer metastasis is significantly increased. CD45+EPC can promote the proliferation and metastasis of tongue cancer by secreting immunosuppressive molecules and ROS.

Objective To analyze the factors associated with postoperative surgical site infection(SSI)in patients with oral and maxillofacial malignancy. Methods A retrospective study was performed on 240 patients after surgical treatment of oral and maxillofacial malignancies. The incidence of postoperative SSI was calculated in terms of the location of tumor. Preoperative serum albumin level, preoperative periodontal calculus, surgical approach, intraoperative antibiotic use, intraoperative blood loss, length of surgery, duration of indwelling catheter, length of hospital stay, postoperative drainage tubes, and length of ICU stay were considered as potential risk factors for SSI in patients with oral and maxillofacial malignancy. These factors were compared between the patients with SSI and those without SSI by univariate analysis. The significant factors identified by univariate analysis(P<0.05)were included in multivariate logistic regression analysis to identify the independent risk factors. Results The highest incidence of SSI was found in patients with tongue cancer, followed by patients with carcinoma of buccal mucosa, carcinoma of lip, and carcinoma of gingiva. No infection was found in the patients with carcinoma of palate(P<0.05). Univariate analysis identifid that preoperative serum albumin level ≤ 35 g/L, preoperative periodontal calculus level 3, surgical approach III(extended resection + cervical lymph node dissection + flap repair), intraoperative use of antibiotics, duration ofindwelling catheter ≤ 24 h, length of hospital stay>18 days, postoperative drainage tube were significant factors of SSI(P<0.05). There were no statistically significant differences between the non-infected group and the infected group in intraoperative blood loss, duration of surgery and ICU stay(P>0.05). Multivariate logistic regression analysis found that preoperative periodontal calculus level 3(OR=7.149, P=0.014), preoperative serum albumin level ≤ 35 g/L(OR = 0.059, P=0.034), surgical approach III(OR=4.135, P=0.024), hospital stay>18 days(OR=24.845, P=0.009)were the independent risk factors for postoperative SSI in patients with oral and maxillofacial malignancy. Conclusions Preoperative periodontal calculus level 3, preoperative serum albumin level ≤ 35 g/L, surgical approach III, and hospital stay>18 days are independent risk factors for SSI in patients with oral and maxillofacial malignancy. Such SSI is relatively more prevalent in patients with tongue cancer. Corresponding measures should be taken for prevention of postoperative SSI in such patients.

OBJECTIVEThis study investigated the effects of systemic administration of oxytocin (OT) in osteoporotic rats on implant osseointegration.

METHODSTwenty rats were randomly assigned to the control and experimental groups. Initially, the rats underwent bilateral ovariectomy. After 12 weeks, an osteoporosis model was established. Each rat received an implant at the distal and middle femoral metaphysis. Simultaneously, systemic administration was conducted with one group receiving subcutaneous injection of OT (1 mg·kg⁻¹ per day), whereas the other group received placebo injection. After treatment for 4 weeks, another surgery was conducted to remove the thigh bones from the rats containing the implants for an eight-week observation. With the employment of micro-CT, histological observation and push-out test, osseointegration was evaluated. While the rats received thigh-bone removal surgery, another surgery was conducted to remove the tibia metaphysis from the rats of both groups to perform histological observation and micro-CT inspection.

RESULTSThe trabecular bone of tibial samples was intensive and formed woven mesh structure in the experimental group compared with the control group. In the experimental group, the relative bone volume/tissue volume surrounding the implant, the bone contact ratio, and the maximum push-out force of the implant were 0.35%±0.06%, 67.25%±9.06%, and (70.32±10.91) N, respectively, the corresponding values were 0.11%±0.02%, 43.25%±7.01% and (21.65±4.36) N in the control group, and the experimental group increased significantly compared with the control group (P<0.05).

CONCLUSIONSSystemic administration of OT cannot only antagonize the negative effects of osteoporosis but can also promote implant healing and osseointegration of pure titanium implants.

Animals ; Dental Implants ; Female ; Femur ; Humans ; Osseointegration ; Osteoporosis ; Ovariectomy ; Oxytocin ; Prostheses and Implants ; Rats ; Rats, Sprague-Dawley ; Tibia ; X-Ray Microtomography