Abstract: To investigate the status and influencing factors of tooth loss among the elderly population in China, so as to provide insights into early prevention of tooth loss. Methods: Based on the Chinese Longitudinal Healthy Longevity Survey (CLHLS), data of the elderly people aged 65 years and older who participated in the survey in 2018 were collected, including demographic information, lifestyle, dietary habits, medical history, number of teeth remaining and self-assessment indicators. The status of tooth loss among the elderly were described based on the standard of 28 teeth, and factors affecting tooth loss were analyzed using a multivariable ordinal logistic regression model. Results: A total of 5 260 people was recruited, including 3 346 males (63.61%) and 1 914 females (36.39%). The median age was 78.00 (interquartile range, 18.00) years. The median number of teeth remaining was 12.00 (interquartile range, 23.00), and the median number of missing teeth was 16.00 (interquartile range, 23.00). Multivariable ordinal logistic regression analysis showed that the elderly who were female (OR=1.270, 95%CI: 1.098-1.470), had advanced age (OR=1.090, 95%CI: 1.083-1.098), lived in rural areas (OR=1.369, 95%CI: 1.165-1.610) and urban areas (OR=1.208, 95%CI: 1.027-1.422), smoked (past, OR=1.471, 95%CI: 1.240-1.746; always, OR=1.545, 95%CI: 1.300-1.838) and brushed teeth less than once a day (OR=1.791, 95%CI: 1.488-2.160) had more missing teeth; while the elderly who had high levels of education (junior high school, OR=0.819, 95%CI: 0.681-0.972; high school, OR=0.626, 95%CI: 0.507-0.771; college and above, OR=0.468, 95%CI: 0.334-0.657), kept physical exercise (OR=0.840, 95%CI: 0.736-0.958) and were overweight/obese (OR=0.868, 95%CI: 0.769-0.980) had less missing teeth. Conclusion Gender, age, residence, educational level, smoking, physical exercise, teeth brushing frequency and overweight/obese are the influencing factors for tooth loss among the elderly in China.

Objective:To investigate the correlations between the bone mineral densities and biomechanical properties on different layers of the cancellous bone in the proximal tibia.Methods:Quantitative CT was conducted of the 15 specimens of adult male tibia. Based on the artificial destruction levels at the trabecular bone on the tibial plateau, the 15 specimens were randomly divided into 3 groups ( n=5): group A (cancellous bone on the 1.5 cm layer below the articular cartilage), group B (cancellous bone on the 3.0 cm layer under the articular cartilage) and group C (cancellous bone on the 0 to 3 cm range of the subchondral bone). After standing positions were simulated in the 3 sets of specimens, they were connected to a biomechanical testing machine. Twenty-four sites were selected and subjected to a vertical load of 600 N. Strain values and overall displacement values of the specimens were recorded before and after trabecular bone destruction. The correlations were analyzed between bone density and displacement values in groups A and B. The strain values before and after trabecular bone destruction, as well as the overall deformation values of the specimens were compared between the 3 groups. Results:The bone densities of specimens in groups A and B were negatively correlated with the displacement values before and after destruction ( P<0.05). Comparisons of strain values at the 24 sites before and after trabecular bone destruction within 3 groups: There were statistically significant differences in the strain values at 8 sites between before and after trabecular bone destruction in group A ( P<0.05). Of the 8 sites, 6 showed increased strains which were mainly concentrated around the insertion point of the anterior cruciate ligament and the medial tibial plateau. There were statistically significant differences in the strain values between before and after trabecular bone destruction at 3 sites in group B ( P<0.05). The strains at all the 3 sites increased, mainly concentrated behind the surface below the level of destruction. There were statistically significant differences in the strain values at 10 sites in group C between before and after trabecular bone destruction ( P<0.05). Of the 10 sites, 5 showed a decrease in the strain which was concentrated above the destruction plane, and 5 showed an increase in the strain which was concentrated below the destruction plane. The overall deformation values of the specimens in groups A, B, and C were (0.033±0.003) mm, (0.015±0.003) mm, and (0.066±0.007) mm, respectively, showing statistically significant differences between the 3 groups ( P<0.05) as well as between any 2 groups ( P<0.05). Conclusions:Bone mineral density in the cancellous bone of the proximal tibia has some value in assessment of the bone strength. Destruction of the proximal tibial cancellous bone can significantly change the strain distribution on the proximal tibia. The proximal cancellous bone of the tibia plays a key role in stress support and load conduction.

The abdominoperineal excision (APE) is still one of the standard operations for low rectal cancer. The exralevator APE can reduce the positive rate of circumferential margin and perforation rate of rectal cancer, but the incidence of postoperative complications is relatively high. With the continuous development of minimally invasive surgery, the transperineal minimally invasive Abdominoperineal excision (Tpm-APE) is proposed. Compared with traditional APE, the Tpm-APE has potential technical advantages, but there is a lack of large sample and multicenter clinical research evidence. The authors share the design and results of an international multicenter clinical study to investigate the clinical practice of Tpm-APE in the treatment of low rectal cancer.

Objective:To investigate the learning curve of laparoscopic transanal total mesorectal excision (taTME) for rectal cancer operated by one or two surgery teams.Methods:The retrospective cross-sectional study was conducted. Based on the concept of real-world research, the clinical data of 1 458 patients undergoing laparoscopic rectal cancer taTME from 44 medical centers who were registered in the Chinese taTME registry collaborative (CTRC) database from May 2010 to May 2020 were collected. The 1 458 patients were divided into cohorts with one surgery team or two surgery teams according to the operation method. Patients with one surgery team underwent taTME by transabdominal operation and then by transanal operation. Patients with two surgery teams underwent taTME by transabdominal and transanal operation simultaneously with duration of the simutaneous operation time ≥30 minutes. The entire surgical process of patients with two surgery teams is not required to be performed by two surgery teams simutaneously. The clinical data were collected from the medical centers with similar operation amount according to the operation time sequence to analyze the difference between different operation stages and explore the learning curve. The operation time was taken as the parameter to carry out cumulative sum analysis and draw the learning curve of laparoscopic rectal cancer taTME in each medical center. The clinicopathological characteristics of patients from two medical centers with the largest difference in learning curves were analyzed. Observation indicators: (1) screening results of clinical data; (2) clinical data collection of patients with one surgery team; (3) surgical situations of laparoscopic rectal cancer taTME from the one surgery team in different operation stages; (4) learning curve of the one surgery team; (5) clinical data collection of patients with two surgery teams; (6) surgical situations of laparoscopic rectal cancer taTME from the two surgery teams; (7) learning curve of the two surgery teams. The cumulative sum was calculated by the CUSUM=∑i=1nXi-U, where Xi represented the operation time of each taTME, U represented the average operation time of all cases, and n represented the operation number. Fitting process was conducted on scatter plot of learning curves. Taking the apex of learning curve as the boundary, the learning curve was divided into two stages. The abscissa corresponding to the apex of learning curve was the number of operations that needed to be performed to cross the learning curve. Measurement data with normal distribution were represented as Mean±SD. Comparison between two groups was conducted using the t test and comparison between multiple groups was conducted using the ANOVA. Measurement data with skewed distribution were represented as M( P25,P75), and comparison between groups was conducted using the Mann-Whitney U test. Comparison of ordinal data was analyzed using the rank sum test. Count data were analyzed using the chi-square test or Fisher exact probability. Results:(1) Screening results of clinical data:the clinical data of 661 patients from 7 medical centers with one surgery team and two surgery teams were collected. (2) Clinical data collection of patients with one surgery team: the clinical data of 312 patients undergoing laparoscopic rectal cancer taTME from 5 medical centers were collected including 42 cases in the number 2 medical center, 97 cases in the number 20 medical center, 82 cases in the number 33 medical center, 35 cases in the number 37 medical center and 56 cases in the number 39 medical center, respectively. (3) Surgical situations of laparoscopic rectal cancer taTME from the one surgery team in different operation stages: three medical centers including the number 2, number 37 and number 39 medical center with close operation volume provided the clinical data of cases distributed in five operation stages. Among the five operation stages, the proportion of high-quality operation of total mesorectal excision (TME) was ≥17/18, the incidence of postoperative complications was ≤13.3%(4/30) and the incidence of anastomotic leakage was ≤10.0%(3/30). There was no significant difference in the TME quality, postoperative complications or anastomotic leakage among the five operation stages ( P>0.05). There was no significant difference in the operation time among the five operation stages ( χ2=6.950, P>0.05). (4) Learning curve of the one surgery team: the number of operations corresponding to the turning point of learning curve in number 2 and number 20 medical center was 22 and 39, respectively. The number of operations corresponding to the turning points of learning curve in number 33 and number 37 medical center was 15, 66 and 10, 28, respectively. The number of operations corresponding to the turning point of learning curve in number 39 medical center was 20. The overall curve of number 20 medical center was in line with the trend of learning curve and 39 cases of operations was the minimum number needed to cross the learning curve. The biggest difference in learning curve was shown between the number 20 and number 33 medical center. Cases with the gender of male or female, age, body mass index, cases classified as stage 1, stage 2, stage 3 or stage 4 of the American Society of Anesthesiologists (ASA) Classification, cases with neoadjuvant therapy, duration of postoperative hospital stay of the number 20 medical center were 77, 20, (60±10)years, 24 kg/m 2(22 kg/m 2, 26 kg/m 2), 1, 88, 8, 0, 8, 8, 11 days (9 days, 13 days), respectively, versus 51, 31, (64±11)years, 23 kg/m 2(21 kg/m 2, 26 kg/m 2), 0, 35, 43, 1, 31, 16 days (13 day, 21 day) of number 33 medical center, showing significant differences in the above indicators between the two medical centers ( χ2 =6.442, t=-2.265, Z=-2.032, -6.870, χ2 =22.120, Z=-8.408, P<0.05). (5) Clinical data collection of the two surgery teams: the clinical data of 259 patients undergoing laparoscopic rectal cancer taTME from 5 medical centers were collected, including 46 cases in the number 2 medical center, 47 cases in the number 8 medical center, 78 cases in the number 18 medical center, 43 cases in the number 33 medical center and 45 cases in the number 44 medical center, respectively. (6) Surgical situations of laparoscopic rectal cancer taTME from the two surgery teams: four medical centers including the number 2, number 8, number 33 and number 44 medical center with close operation volume provided the clinical data of cases distributed in four operation stages. Among the four operation stages, the proportion of high-quality operation of TME was ≥50.0%(13/26), the incidence of postoperative complications was ≤35.0%(14/40) and the incidence of anastomotic leakage was ≤22.5%(9/40). There was no significant difference in the TME quality, postoperative complications or operation time among the four operation stages ( χ2 =3.252, 4.733, 8.848, P>0.05). There was a significant difference in the incidence of anastomotic leakage among the four operation stages ( P<0.05). (7) Learning curve of the two surgery teams: the number of operations corresponding to the turning point of learning curve in number 2 and number 8 medical center was 28 and 16, respectively. The number of operations corresponding to the turning points of learning curve in number 18, number 33 and number 44 medical center was 12 and 58, 10 and 36, 14 and 36, respectively. The overall curve of number 2 medical center was in line with the trend of learning curve and 28 cases of operations was the minimum number needed to cross the learning curve. The biggest difference in learning curve was shown between the number 2 and number 33 medical center. The age and cases with tumor in stage T0 and (or) Tis, stage T1, stage T2, stage T3 or stage T4 of the T staging of the number 2 and number 33 medical center were (60±12)years, 3, 1, 9, 11, 20 and (65±10)years, 2, 3, 22, 15, 0, respectively, showing significant differences in the above indicators between the two medical centers ( t=-2.280, Z=-4.033, P<0.05). Conclusion:Thirty-nine cases of operations was the minimum number for the one surgery team to cross the learning curve of laparoscopic rectal cancer taTME and 28 cases of operations was the minimum number for the two surgery teams to cross the learning curve of laparoscopic rectal cancer taTME.

Objective:To investigate the effects of cone beam computed tomography measurement of maxillary anterior teeth on implant success and patient satisfaction of maxillary anterior teeth.Methods:120 patients who underwent maxillary anterior teeth implantation in Hangzhou Dental Hospital from October 2017 to October 2019 were included in this study. They were randomly assigned to receive either conventional maxillary anterior teeth implantation (control group, n = 60) or cone beam computed tomography measurement of maxillary anterior teeth and maxillary anterior teeth implantation (study group, n = 60). The implant success rate was compared between the two groups. Alveolar bone thickness and ISQ value immediately, 3 and 12 months after implantation as well as patient satisfaction were compared between the two groups. Results:Implant success rate in the observation group was significantly higher than that in the control group [96.67% (58/60) vs. 85.00% (51/60), χ2 = 4.904, P < 0.05]. In the observation group, alveolar bone thickness at 3 and 12 months after implantation was (1.53 ± 0.05) mm and (1.78 ± 0.12) mm, respectively, which was significantly higher than that in the control group [(1.46 ± 0.04) mm, (1.64 ± 0.10) mm, t = 9.839, 8.066, both P < 0.001]. In the observation group, ISQ value at 3 and 12 months after implantation was (76.83 ± 5.49) and (82.91 ± 4.85), respectively, which was significantly higher than that in the control group [(67.81 ± 4.61), (74.18 ± 5.21), t = 11.324, 11.038, both P < 0.001). Total satisfaction rate in the observation group was significantly higher than that in the control group [95.00% (57/60) vs. 81.67% (49/60), χ2 = 5.175, P < 0.05]. Conclusion:Cone beam computed tomography measurement of maxillary anterior teeth can help increase implant success rate and patient satisfaction.

It is critical to ensure complete mesorectal excision for rectal cancer surgery.Different surgical approaches including laparoscopy and expensive robotic surgical system,are currently unable to achieve the same therapeutic effects as traditional open surgery.Transanal total mesorectal excision (TaTME) is a new technique in rectal cancer surgery in recent years,which can effectively solve the problems of traditional transabdominal approach due to poor operative vision caused by low pelvic anatomy.After nearly 10 years of development,TaTME has shown the potential to improve the quality of rectal cancer surgery.With the continued development of emerging surgical techniques,TaTME relies on extensive,continuous structured training and high-quality clinical researches.

Colorectal anastomosis remains a key aspect in mid- and lower-rectal surgery, particularly in patients who are male, obese, status post neoadjuvant chemoradiation, or possess narrow pelvic anatomy. Transanal total mesorectal excision (taTME) and transabdominal total mesorectal excision (TME) both primarily allow position of the tumor to dictate whether circular stapling or hand-sewing is utilized to achieve anastomosis. Given that taTME only requires a single circular stapler to achieve anastomosis, it consequently decreases the risk of jeopardizing blood supply to the anastomotic site. Should transanal hand-sewing be pursued, numerous points in performing the purse-string suture warrant particular attention: (1) Before suturing, separate the distal rectum to be anastomosed from the surrounding tissues, and ensure the full-layer suture of the distal purse-stitched suture. (2) It is recommended that beginners complete the suturing process under direct visualization without removing the transanal platform. (3) Commonly used anastomosis designs include end-to-end, side-to-end, J-pouch, or coloplasty, depending on patient characteristics and surgeon preferences. Our single-institution clinical experience suggests that taTME patients who underwent neoadjuvant chemoradiation or transanal hand-sewn anastomosis should still have a temporary colostomy created. To date, literature has yet to demonstrate the superiority of taTME anastomosis outcomes. This publication aims to point out anastomosis techniques and safety pointers, as well as clinical experiences.
Anastomosis, Surgical ; Digestive System Surgical Procedures ; Humans ; Male ; Neoadjuvant Therapy ; Rectal Neoplasms ; Rectum ; surgery

Objective: To summarize the clinical experience of cardiopulmonary bypass(CPB) in acute type A aortic dissection received aortic arch reconstruction on age over 70 years patients. Methods: From April 2013 to December 2017, 35 elderly patients aged over 70 who were involved the aortic arch, brachiocephalic trunk, left common carotid artery and left subclavian artery and severe arch lesions, large false lumen and large rupture risk of acute A aortic dissection were reconstructed by triple-branched stent graft in emergency extracorporeal circulation. During the period of cardiopulmonary bypass, selective cerebral perfusion and discontinuous arrest under moderate hypothermia(25 degrees C) were used to reduce the time of cerebral ischemia and hypoxia, and to strengthen the management of the protection of important organs. Results: Cardiopulmonary bypass time was(144.85±32.98)minutes, and aortic cross clap time was(51.82±17.59)minutes, and selective cerebral perfusion time was(12.17±4.70)minutes, discontinuous arrest time was(4.50±3.54) minutes, the lower body arrest time was(16.6±7.49)minutes. All patients were smoothly weaned from cardiopulmonary bypass.35 patients resuscitated within 48 hours, of which 3 patients had transient mental disorders in the early stage and recovered before hospital discharge; 2 patients had cerebral infarction. Hospital mortality in this group was 17.1%(6/35). Conclusion Advanced age is not a contraindication to the reconstruction of the arch of the aortic dissection. Reasonable management of cardiopulmonary bypass can provide an important guarantee for the reconstruction of the elderly patients with acute type A aortic dissection.

Objective To compare the efficacy and safety of tenofovir disoproxil fumarate ( TDF) and entecavir(ETV) in the treatment of chronic hepatitis B(CHB) with positive hepatitis B E antigen(HBeAg). Methods A total of 104 cases with newly diagnosed HBeAg positive CHB were selected and randomly divided into TDF group and ETV group,with 52 cases in each group. The TDF group was given 300mg/d TDF,and the ETV group was given 0. 5mg/d ETV. All the patients were continuously treated for 12 months. The serum HBV DNA, HBeAg and ALT levels before and after treatment were compared between the two groups. Results Before treatment,there were no statistically significant differences in serum HBV DNA,HBeAg and ALT levels between the two groups ( t=0. 12, 1. 51,1. 62,all P＞0. 05). The serum HBV DNA,HBeAg and ALT levels in the two groups were decreased after treatment,and the decrease of serum HBV DNA level in the TDF group was more significant than that in the ETV group,the difference was statistically significant(t =3. 54,P ＜0. 05),but there were no statistically significant differences in serum HBeAg and ALT levels between the two groups(t=0. 04,0. 79,all P＞0. 05). The total effective rate of the TDF group was 92. 31% (48/52),which was significantly higher than 76. 92% (40/52) in the ETV group (χ2=4. 73,P＜0. 05). During treatment,the incidence rate of adverse reaction of the TDF group was 7. 69% (4/52),which was lower than 11. 54% (6/52) of the ETV group,but the difference was not statistically significant (χ2=0. 44,P＞0. 05). Conclusion TDF has better clinical effect in treating newly diagnosed HBeAg positive CHB than ETV due to TDF can inhibit HBV DNA replication significantly,but the safety of TDF and ETV is similar.

Objective To observe the serum vascular endothelial growth factor (VEGF),apelin and heme oxygenase-1 (HO-1) levels in patients with type 2 diabetes mellitus (T2DM) and to explore their their relationship with diabetic retinopathy (DR).Methods A total of 208 patients with T2DM and 50 healthy subjects (control group) from the Central Hospital of Western Hainan during January 2014 and December 2017 were selected in this study.Vision,slit lamp microscope,indirect ophthalmoscope and FFA examinations were performed on all the subjects.According to the results of the examinations combined with the DR clinical staging criteria,the patients were divided into non-DR (NDR) group,non-proliferative DR (NPDR) group,and proliferative DR (PDR) group,with 72,76 and 60 patients in each,respectively.The clinical data of each group were recorded,and the levels of fasting blood glucose (FPG),HbA1c,total cholesterol (TC),three acylglycerol (TG),high density lipoprotein (HDL-C),low density lipoprotein (LDL-C),VEGF,apelin and HO-1 were detected in each group.The receiver operating characteristic curve (ROC) were used to analyze the value of VEGF,apelin and HO-1 in predicting the occurrence of PDR.Correlation analysis of serum VEGF,Apelin and HO-1 with clinical parameters in PDR patients by Pearson correlation analysis.Results The level of VEGF (56.82± 10.16 vs 91.74±22.83,140.15±36.40,195.28±42.26 pg/ml)and apelin (2.95±0.53 vs 4.68±0.74,7.25±1.13,10.16± 1.35 ng/ml) in PDR group were significantly higher than those in NPDR,NDR and control groups (F=17.306,21.814;P＜0.05).The level of HO-1 (50.37±10.14 vs 43.58±8.16,30.25t6.28,22.60±4.72 mmol/L) in PDR group was significantly lower than those in NPDR,NDR and control groups (F=15.827,P＜0.05).The ROC curve analysis showed that the best cut-offvalues of serum VEGF,apelin and HO-1 were 162.50 pg/ml,8.30 ng/ml,27.13 mmol/L,and the three combined to predict PDR of AUC (95％CI)was 0.906 (0.849-0.962),and their sensitivity (90.3％) and specificity (83％) were better.The correlation analysis showed that the VEGF,apelin and HO-1 of PDR patients were correlated with the course of diabetes (r=0.382,0.416,-0.36;P＜0.05),FPG (r=0.438,0.460,-0.397;P＜0.05) and HbAlc (r=0.375,0.478,-0.405;P＜0.05),and the serum VEGF were correlated with apelin and HO-1 (r=0.793,-0.594;P＜0.01).Conclusion Elevated serum VEGF and apelin levels and reduced HO-1 levels are associated with the progression of DR,and the three combination helps predict the occurrence of PDR.