OBJECTIVE: To investigate the clinical application effect of the along-axis extraction method in the extraction of impacted mandibular third molars (IMTM) and to compare the biomechanical characteristics of different root extraction techniques through three-dimensional finite element analysis. METHODS: A total of 68 patients requiring IMTM extraction were enrolled and randomly divided into two groups: the experimental group underwent the along-axis extraction method, while the control group underwent the traditional buccal bone removal and root extraction method. The duration of the procedure, intraoperative and postoperative complications were recorded. Three-dimensional finite element analysis further revealed the stress distribution in the tooth root, jawbone, periodontal ligament, and mandibular canal during different root extraction methods. RESULTS: The duration of root extraction, pain score and swelling on the first postoperative day in the control group were (7.87±3.90) min, 4.62±1.90 and (11.37±5.12) mm, respectively, which were significantly higher than those in the experimental group [(5.74±2.37) min, 3.87±1.19 and (7.22±3.39) mm, respectively]. The root fracture rate and lingual bone plate fracture rate in the control group were significantly higher than those in the experimental group (P < 0.05). The results of finite element analysis showed that the control group ' s lingual al-veolar bone had the higher peak equivalent stress, and lingual bone plate fracture was prone to occur. The periodontal ligament of the experimental group had the higher equivalent stress value, making it more likely to rip and more likely to cause root displacement. When subjected to force, the experimental group' s instantaneous root displacement was higher, but the control group ' s root displacement was more pronounced in the lingual direction. CONCLUSION This study suggests that the along-axis extraction me-thod can not only effectively shorten the operative time but also reduce postoperative complications after extraction of impacted mandibular third molars, and enhance the safety of the operation and the patient' s comfort. Three-dimensional finite element analysis shows the biomechanical characteristics of various root extraction techniques visually, serves as a valuable guide for choosing and refining clinical surgical techniques, and confirms that extracting a tooth' s root along its long axis yields better clinical results.
Humans ; Finite Element Analysis ; Tooth, Impacted/surgery* ; Tooth Extraction/methods* ; Molar, Third/surgery* ; Mandible/surgery* ; Imaging, Three-Dimensional ; Female ; Adult ; Biomechanical Phenomena ; Male ; Tooth Root/surgery* ; Young Adult ; Adolescent

Bone grafting is a primary method for treating bone defects. Among various graft materials, xenogeneic bone substitutes are widely used in clinical practice due to their abundant sources, convenient processing and storage, and avoidance of secondary surgeries. With the advancement of domestic production and the limitations of imported products, an increasing number of bone filling or grafting substitute materials isentering clinical trials. Relevant experts have drafted this consensus to enhance the management of medical device clinical trials, protect the rights of participants, and ensure the scientific and effective execution of trials. It summarizes clinical experience in aspects, such as design principles, participant inclusion/exclusion criteria, observation periods, efficacy evaluation metrics, safety assessment indicators, and quality control, to provide guidance for professionals in the field.
Humans ; Bone Substitutes/therapeutic use* ; Randomized Controlled Trials as Topic/methods* ; Consensus ; Bone Transplantation ; Research Design

Objective:To explore the reconstruction strategy and technical selection of S3 hepatic vein with middle hepatic vein confluence in pediatric liver transplantation(LT)using living donor left lateral segment to lower the risk of vascular complications caused by variant grafts.Methods:From January 2015 to June 2021, retrospective analysis is performed for 840 consecutive cases of pediatric living donor LT using left lateral segment(LLS).There are 32 cases of S3 hepatic vein with middle hepatic vein confluence with an overall incidence of 3.81%.Individualized reconstruction strategies are implemented according to the specific conditions of variation and different interposition vessels available: group I unification venoplasty technique with interposition vein graft is employed for reconstructing HV from grafts, prolonged S3 is formed into a single opening with S2 and then anastomosed with recipient(21 cases); group Ⅱ dual HV reconstructions were performed(11 cases); venoplasty of recipients'LHV, MHV and inferior vena cava(IVC)is performed for creating a large orifice for anastomosis with S2 HV from graft and S3 is anastomosed with stump of recipient right HV directly or interposed blood vessels.Clinical features and prognosis of two groups, the incidence, treatment and prognosis of HVOO and the incidence of HVOO between variant and non-variant groups were compared.Results:The median follow-up time of variant group(32 cases)is 23.8 month with an incidence of HVOO at 15.6%.During the same period, the non-variant group incidence of HVOO is 4.5%.There is inter-group statistical difference( P=0.014).The only statistical difference between groups Ⅰ and Ⅱ is ultrasonic blood flow velocity of S3 HV at 14 POD [(39.15±16.37)vs(20.05±8.52)cm/s, P=0.001].HVOO occurred in 7 cases and 6 cases respectively in groupⅠ and group Ⅱ.There is no statistical difference( P=0.310).There are no intractable vascular complications.Long-term vascular patency of allogeneic and autologous interposition vein is satisfactory and there is no graft failure or mortality related to HVOO. Conclusions:Selecting strategies and techniques for reconstructing S3 hepatic vein with middle hepatic vein confluence at our center are reasonable, safe and effective.And the overall treatment efficacy is satisfactory.Reasonable selection of multidimensional reconstruction methods and accurate application of various technologies are conducive to improving patient prognosis.

Objective:To evaluate the effect of parental liver donation on early acute cellular rejection(ACR)after liver transplantation(LT)in children aged under one year.Methods:From January 2018 to January 2021, retrospective review is conducted for clinical data of living donor LT recipients and donors aged under 1 year at Tianjin First Central Hospital.Donor livers are assigned into two groups of paternal donor liver(156 cases)and maternal donor liver(206 cases)according to the source of donor liver, Clinical characteristics and postoperative ACR occurrence of two groups are analyzed.Results:The rates of ACR during early postoperative period is 14.9%(54/362), 20.5%(32/156)in paternal liver donor group and 10.7%(22/206)in maternal liver donor group.There is statistically significant difference(λ 2=6.763, P=0.009).In analysis of gender matching of donor recipients, the rates of ACR is 22.6% in paternal donor group and 10.3% in maternal donor group.There is statistically significant difference(λ 2=5.411, P=0.020).Median time of initial postoperative ACR is 13.00(8.25~20.25)day in paternal liver donor group and 17.00(9.00~28.25)day in maternal donor group.The difference is not statistically significant( P>0.05). ACR is mostly mild-to-moderate in two groups . Conclusions:In living donor LT for children aged under 1 year, the rates of early ACR is lower for maternal donor than that for paternal donor, especially in female recipients.

Objective:Comparison of four methods in intraoperative abduction angles (AA) measurements of human cast immobilization in developmental dysplasia of the hip (DDH) by visual inspection and electronic software according to different body surface markers.Methods:Data were retrospectively collected from January 2019 to November 2021 in a total of 27 patients (54 hips) who underwent closed or simple open reduction. There were 6 males and 21 females with an average age of 13.2 months. Five doctors used visual inspection and mobile phone software to measure the AA of the hip joint immediately during the operation, and compared with the postoperative MRI measurement results (AA-MRI). The four methods of intraoperative measurement were: Junior visualization (AA-JV), the intersection angle between the line connecting the center of the popliteal fossa and the contact center of the plaster frame and the line connecting the two ischial tuberosities; the same methods as method one by Senior visualization (AA-SV); the intersection angle between the line connecting the center of the popliteal fossa and the center of the anus and the line connecting the ischial tubercle (anus-popliteal, AA-AP); the intersection of the vertical line between the center of the popliteal fossa and the groin and the horizontal line of the center of the anus and the vertical line connecting the two ischial tuberosities intersect (anus-groin crease-popliteal, AA-AGCP). The t-test, correlation coefficient, linear regression and Bland-Altman test were used to evaluate the measurements. Results:Comparing the four intraoperative and postoperative AA-MRI measurement methods, AA-JV (42.69°±4.13°) < AA-SV (44.80°±4.08°) < AA-AGCP (46.25°±5.15°) < AA-MRI (47.68°±4.21°) < AA-AP (51.77°±5.30°), and the difference between AA-JV and AA-SV, AA-AP and AA-AGCP was statistically significant ( t=2.53, P=0.013; t=5.47, P=0.001), there was no significant difference between AA-AGCP and AA-MRI ( t=1.57, P=0.118). The inter-group agreement of the five methods ICC test ranged from 0.807 to 0.892, and the intra-group average agreement of AA-MRI was 0.948. All ICC results were greater than 0.75 with good agreement. Linear regression results showed that the four intraoperative measurement methods had a good or moderate linear relationship with AA-MRI, AA-AGCP ( R 2=0.499)>AA-AP ( R 2=0.318)>AA-SV ( R 2=0.253)>AA-JV ( R 2=0.217), AA-AGCP was the best measurement method. The results of Bland-Altman scatterplot of AA-AGCP and AA-MRI were in good agreement, the mean and standard deviation of bias were -0.796±3.247, and the limit of agreement was 95% LoA (-7.16, -5.57). Conclusion:The AA method of visualization before Spica casting was smaller than truth. The method AA-AGCP objectively by landmarks was the advocated means measuring abduction angle during operation with highly consistency, agreement and easily performed.

Objective:To evaluate the prognosis of tooth extraction in elderly mellitus patients with fasting plasma glucose (FPG)>8.88 mmol/L and ≤10.00 mmol/L.Methods:This study was a prospective cohort study. One hundred elderly mellitus patients, 53 males and 47 females, aged 65-95 years old (75.8±8.0), were recruited for tooth extraction at the ECG monitoring out-patient clinic in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from Oct 2018 to Oct 2019. Fifty cases were selected into the observation group with FPG>8.88 mmol/L and ≤10.00 mmol/L before tooth extraction, while the rest 50 cases were in the control group with FPG≤8.88 mmol/L. The levels of glycosylated hemoglobin (HbA1c) of patients were required to be≤8.5% before tooth extraction in both groups. Post-operative pain, swelling, pus discharge, fistula at local sockets and systemic fever were observed 24 h and 1 week after the extraction. The healing of tissues around the extraction socket was observed 1 month after operation. The correlation between blood glucose control target and the effects of socket healing before and after tooth extraction was analyzed statistically using SPSS 25.0 software.Results:The pre-operative FPG levels of observation group and control group were (6.92±0.99) and (9.88± 0.68) mmol/L, and HbAlc levels were (6.76±0.83)% and (7.69±0.75)%, respectively. There were no significant differences in age, gender, diabetes history, extraction position, gingival index and tooth looseness between the two groups ( P>0.05). Ninety-four percent (47/50 in each group) of patients in the two groups healed well within 24 h after the extraction. There were 6 patients, 3 in each of the two groups, complained tolerable post-operative pain in tooth extraction sockets. However, no redness, swelling and pus in the surrounding tissues were observed. There was no statistical difference of socket healing after the extractions between two groups ( P>0.05). Conclusions:The pre-operative levels of FPG≤10.00 mmol/L and HbA1c≤8.5% are reasonable creteria for evaluating tooth extraction risk for the elderly diabetic patients.

Objective:To evaluate the preliminary clinical effect of flap-raising and cortical-perforation based extraction method in patients with potential risk of medication-related osteonecrosis of the jaw (MRONJ).Methods:Eighteen patients, who needed teeth extraction in the Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology from February 2016 to November 2020, with a history of using anti-resorption/anti-angiogenesis medication were included in this retrospective study. According to the characteristics of the patient′s medication history, patients were stratified into three categories, low-dose anti-resorption drug group, high-dose anti-resorption drug group, and high-dose anti-resorption combined with anti-angiogenesis targeted drug group. There were 15 females and 3 males, the average age was 62.4 years (range from 27 to 87 years) old. A total of 31 teeth were indicated for extraction due to chronic infection. The flap-raising and cortical-perforation techniques were used to extract the affected teeth, and the patients were followed up closely. By observing the healing status and swelling degree of the mucosa of tooth extraction sites, whether there was a fistula, pus and bone exposure of jaw bone,the healing of the tooth extraction sites were evaluated.Results:Among the 18 patients, there were 9 cases of osteoporosis and 9 cases of malignant tumors. Classified by medication-using history, 10 cases were treated with low-dose anti-resorption drugs, 5 cases were high-dose anti-resorption drugs, and 3 cases were high-dose anti-resorption drugs combined with anti-angiogenesis drugs. A total of 31 teeth of the patients were extracted by flap-raising and cortical-perforation based extraction method. Thirteen patients completed treatment underwent local anesthesia and five cases were performed under general anesthesia. The shortest follow-up period was 3 months with an average of 13.2 months. Seventeen patients recovered well after the tooth extraction. One patient had the mandible exposed at one extraction site one month after the surgery, resulting in MRONJ.Conclusions:In patients with potential risks of MRONJ, the application of flap-raising and cortical-perforation based teeth extraction method could safely and effectively alleviate the dental inflammation in the oral cavity.

Objective:This study will analyze the clinical characteristics and risk factors that may be related to the 30-day mortality of patients infected with CRAB in intensive care unit (ICU), and explore the resistance of CRAB and its influence on mortality.Methods:From December 2012 to February 2021, 173 ICU patients with CRAB infection in the Fifth Medical Center of PLA General Hospital were selected as the research objects, and the relevant data were collected for retrospective analysis. There were 119 cases (68.8%) in survival group and 54 cases (31.2%) in the non-survival group. Patients with CRAB infection were (52.9±13.5) years old, including 140 males (80.9%) and 33 females (19.1%).The first detected CRAB was collected, and antibiotic sensitivity test was conducted after the strain was resuscitated to analyze the antibiotic resistance. Univariate and multivariate Cox models were used to analyze independent risk factors associated with 30-day mortality in patients with CRAB infection.Results:Univariate and multivariate Cox analysis showed that acute physiology and chronic health evaluation scoring system Ⅱ(APACHE Ⅱ)(HR=1.058, 95% CI:1.012-1.106, P=0.013) and septic shock (HR=6.240, 95% CI:2.227-17.483, P<0.001) were independent risk factors related to 30-day mortality in ICU patients with CRAB. Treatment with β-lactamase inhibitor (HR=0.496, 95% CI: 0.275-0.893, P<0.019) can reduce the 30-day mortality of patients with CRAB infection in ICU. The resistance rate of CRAB to cephalosporins, carbapenems, aminoglycosides and quinolones were more than 80%. The survival rate of patients infected by aminoglycoside resistant CRAB is low(χ2=4.012, P<0.05). Conclusion:The APACHE Ⅱ score, septic shock and use of β-lactamase inhibitors were independent factors associated with the 30-day mortality in ICU patients with CRAB infection.

Objective:This study will analyze the clinical characteristics and risk factors that may be related to the 30-day mortality of patients infected with CRAB in intensive care unit (ICU), and explore the resistance of CRAB and its influence on mortality.Methods:From December 2012 to February 2021, 173 ICU patients with CRAB infection in the Fifth Medical Center of PLA General Hospital were selected as the research objects, and the relevant data were collected for retrospective analysis. There were 119 cases (68.8%) in survival group and 54 cases (31.2%) in the non-survival group. Patients with CRAB infection were (52.9±13.5) years old, including 140 males (80.9%) and 33 females (19.1%).The first detected CRAB was collected, and antibiotic sensitivity test was conducted after the strain was resuscitated to analyze the antibiotic resistance. Univariate and multivariate Cox models were used to analyze independent risk factors associated with 30-day mortality in patients with CRAB infection.Results:Univariate and multivariate Cox analysis showed that acute physiology and chronic health evaluation scoring system Ⅱ(APACHE Ⅱ)(HR=1.058, 95% CI:1.012-1.106, P=0.013) and septic shock (HR=6.240, 95% CI:2.227-17.483, P<0.001) were independent risk factors related to 30-day mortality in ICU patients with CRAB. Treatment with β-lactamase inhibitor (HR=0.496, 95% CI: 0.275-0.893, P<0.019) can reduce the 30-day mortality of patients with CRAB infection in ICU. The resistance rate of CRAB to cephalosporins, carbapenems, aminoglycosides and quinolones were more than 80%. The survival rate of patients infected by aminoglycoside resistant CRAB is low(χ2=4.012, P<0.05). Conclusion:The APACHE Ⅱ score, septic shock and use of β-lactamase inhibitors were independent factors associated with the 30-day mortality in ICU patients with CRAB infection.

Objective To investigate the shaping rules of the femoral heads in the morphological perspective.The research objects are hips of normal children and children who have developmental dysplasia of the hip(DDH) and after closed reduction or limited open reduction.At the same time measuring and analyzing normal hip femoral head form changing with the children's age.Methods Collecting the DDH cases that after closed reduction and limited open reduction from June 2013 to December 2015.The follow-up period was more than 1 year.MRI images were collected before surgery,6 months after surgery,1 year after surgery,and 2 years after surgery.In addition,normal hip joint MRI images from 0 to 18 years old were collected for controlled study.Descriptive data on the affected side,healthy side and normal hip joint morphology of the hip dislocation were statistically analyzed.Results (1) The mean eccentricity of femoral head in normal hip decreased from (0.362 ±0.069) at 1-2 years to(0.141 ±0.028) at 18-19 years.(2) The eccentricity of femoral head before closed reduction and limited open reduction were both greater than those of healthy side.There was no significant difference in the eccentricity of the femoral head between the healthy side and the affected side at 1 year after closed reduction (P =0.211).There was no significant difference in the diameter of the bilateral femoral heads (P =0.871).The eccentricity of the bilateral femoral heads remained different at 2 years after limited open reduction (P =0.028),and the diameter of the affected femoral head exceeded the healthy side 1 year after surgery (P =0.001).Conclusion The shape of the femoral head of normal children gradually approaches the spherical shape with age.One year after closed reduction of DDH,the shape and size of the affected femoral head are close to the healthy side,and the femoral head of the affected side increases more than the healthy side in 1 ～ 2 years after open reduction and the morphology is still different.