Objective By using the computational fluid mechanic(CFD)method the tandem carotid artery stenosis(TCAS)was simulated on the model,and to compare the postoperative hemodynamic changes of different surgical procedures.Methods One patient with tandem stenosis of internal carotid artery(ICA)and common carotid artery(CCA)was selected.CFD technique was used to establish four three-dimensional(3-D)models of the carotid bifurcations,including one model of a real patient and three models of presumptive surgery.The hemodynamic analysis was performed with these models so as to explore the development mechanism of TCAS and to discuss the selection of suitable surgical plan.Results In tandem stenosis,the stenosis was preferentially formed in CCA and subsequently led to ICA stenosis.The local hemodynamic situation in TCAS was more complex and more risky than in single carotid artery stenosis.In tandem stenosis,the treatment of one stenosis site would affect the blood flow at the next stenosis site and cause restenosis or plaque rupture.Conclusion In treating patients with TCAS,CFD simulation examination should be performed when the surgical plan is formulated,which can help clinicians to predict the postoperative changes in blood flow and to choose the appropriate surgical plan.

Objective:To investigate the short-term outcome of transoral robotic thyroidectomy.Methods:This is a retrospective case series study. The clinicopathologic characteristics and postoperative results of 107 patients who underwent transoral robotic thyroidectomies in the Department of Thyroid and Breast Surgery of the 960 th Hospital of People′s Liberation Army from May 2020 to August 2023 were retrospectively analyzed. There were 12 males and 95 females, with an age of (31.8±9.4) years (range: 11 to 55 years), including 20 benign tumors and 87 thyroid papillary carcinoma. Postoperative follow-up was carried out through returning visit and telephone, mainly to observe the recovery of postoperative complications, cosmetic effects and recurrence results. Results:All transoral robotic thyroidectomy was successfully completed without conversion to open surgery. The tumor size of thyroid papillary carcinoma patients was (5.6±2.7) mm (range: 2 to 15 mm). Furthermore, central cervical lymph node metastasis was found in 45 cases. The number of central cervical lymph nodes retrieved and metastasized ( M(IQR)) were 11 (8) (range: 3 to 26) and 1 (3) (range: 0 to 13), respectively. There was no recurrent laryngeal nerve injury and permanent hypoparathyroidism. The transient hypoparathyroidism after surgery was 8 cases. Other complications occurred as follows: postoperative infection ( n=1), left submandibular perforation ( n=1), skin scald ( n=1), and perioral numbness ( n=1), oral tear ( n=2). The postoperative stay was 6 (2) days (range: 3 to 11 days). No local lymph node recurrence or metastasis occurred after a follow-up of (22.6±10.0) months (range: 1.0 to 37.4 months). All patients were satisfied with the postoperative cosmetic results, the aesthetic effect score was 9.3 (0.2) (range: 8.4 to 9.6) one month after surgery. Conclusion:For highly screened patients with early thyroid cancer, experienced surgeons can perform a transoral robotic thyroidectomy that has excellent cosmetic results.

Objective:To investigate the short-term outcome of transoral robotic thyroidectomy.Methods:This is a retrospective case series study. The clinicopathologic characteristics and postoperative results of 107 patients who underwent transoral robotic thyroidectomies in the Department of Thyroid and Breast Surgery of the 960 th Hospital of People′s Liberation Army from May 2020 to August 2023 were retrospectively analyzed. There were 12 males and 95 females, with an age of (31.8±9.4) years (range: 11 to 55 years), including 20 benign tumors and 87 thyroid papillary carcinoma. Postoperative follow-up was carried out through returning visit and telephone, mainly to observe the recovery of postoperative complications, cosmetic effects and recurrence results. Results:All transoral robotic thyroidectomy was successfully completed without conversion to open surgery. The tumor size of thyroid papillary carcinoma patients was (5.6±2.7) mm (range: 2 to 15 mm). Furthermore, central cervical lymph node metastasis was found in 45 cases. The number of central cervical lymph nodes retrieved and metastasized ( M(IQR)) were 11 (8) (range: 3 to 26) and 1 (3) (range: 0 to 13), respectively. There was no recurrent laryngeal nerve injury and permanent hypoparathyroidism. The transient hypoparathyroidism after surgery was 8 cases. Other complications occurred as follows: postoperative infection ( n=1), left submandibular perforation ( n=1), skin scald ( n=1), and perioral numbness ( n=1), oral tear ( n=2). The postoperative stay was 6 (2) days (range: 3 to 11 days). No local lymph node recurrence or metastasis occurred after a follow-up of (22.6±10.0) months (range: 1.0 to 37.4 months). All patients were satisfied with the postoperative cosmetic results, the aesthetic effect score was 9.3 (0.2) (range: 8.4 to 9.6) one month after surgery. Conclusion:For highly screened patients with early thyroid cancer, experienced surgeons can perform a transoral robotic thyroidectomy that has excellent cosmetic results.

Objective:To explore the technique and clinical effects of free medial plantar flap on reconstruction of the severe defect of thumb caused by electric burn.Methods:Surgical techniques and clinical effects were explored in reconstruction with free medial plantar flap for treatment of severe electric burns of thumbs. From July 2016 to July 2021, 18 patients suffered from severe electric burns of thumbs were admitted in the Department of Burn, Zhengzhou First People's Hospital. All the wounds were the entrance of electric burns. After thorough debridement, the arteries, nerves, tendons, phalanges and interphalangeal joints were exposed to various degrees. Damaged digital proper palmar arteries were ligated and defected proper palmar digital nerves were marked and further anastomosed with the nerves carried by the flap. Palmaris longus tendon grafts were employed to reconstruct the defects of flexor pollicis longus tendon. Wounds were closed by transfer of free medial plantar flaps, and the flap donor sites were closed by inguinal skin grafts. Survival of the flap was observed 1 week after surgery, and the survival of the skin graft in the foot donor site 12 days after surgery. Outpatient follow-up including observation of the appearance and texture of the flap, evaluation of sensory function, thumb alignment and finger flexion according to the Evaluation Trial Standards of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association. Evaluate the scar hyperplasia in the foot donor site and the standing and walking functions of the donor foot.Results:All flaps survived,at 1 week after surgery. On the 12th day after surgery, all 16 foot flap survived, and 2 patients had local necrosis, and the necrosis healed completely after dressing change for 10 days, the wound healed completely. Among them, 3 patients without tendon transfer experienced a rupture of the flexor pollicis longus tendon at 2 months after surgery, and underwent another palmaris longus tendon transfer. After the surgery, functional exercise was performed with the palm and flexor fingers. After 6-12 months of follow-up, the blood supply, appearance, and texture of the flap were good and similar to that of the palmar skin of the thumb, with varying degrees of recovery in sensation. The TPD was 6-11 mm, and the thumb was restored to varying degrees. According to the Evaluation Trial Standards of Upper Limb Partial Functional of Hand Surgery of Chinese Medical Association, 13 cases in excellent and 5 cases in good. Mild scar hyperplasia remains in the flap site of donor feet, which does not affect the standing and walking functions of the donor foot.Conclusion:The texture of medial plantar skin is similar to that of palmar skin, with good wear resistance and good sensation. Furthermore, it causes a little damage to the donor site and without obvious complication. The medial plantar flap is ideal for reconstruction of a severe wound caused by electric burn in thumb.

Objective:To evaluate the safety of double and a half layered esophagojejunal anastomosis in radical gastrectomy.Methods:This prospective, multi-center, single-arm study was initiated by the Affiliated Cancer Hospital of Zhengzhou University in June 2021 (CRAFT Study, NCT05282563). Participating institutions included Nanyang Central Hospital, Zhumadian Central Hospital, Luoyang Central Hospital, First Affiliated Hospital of Henan Polytechnic University, First Affiliated Hospital of Henan University, Luohe Central Hospital, the People's Hospital of Hebi, First People's Hospital of Shangqiu, Anyang Tumor Hospital, First People's Hospital of Pingdingshan, and Zhengzhou Central Hospital Affiliated to Zhengzhou University. Inclusion criteria were as follows: (1) gastric adenocarcinoma confirmed by preoperative gastroscopy;(2) preoperative imaging assessment indicated that R0 resection was feasible; (3) preoperative assessment showed no contraindications to surgery;(4) esophagojejunostomy planned during the procedure; (5) patients volunteered to participate in this study and gave their written informed consent; (6) ECOG score 0–1; and (7) ASA score I–III. Exclusion criteria were as follows: (1) history of upper abdominal surgery (except laparoscopic cholecystectomy);(2) history of gastric surgery (except endoscopic submucosal dissection and endoscopic mucosal resection); (3) pregnancy or lactation;(4) emergency surgery for gastric cancer-related complications (perforation, hemorrhage, obstruction); (5) other malignant tumors within 5 years or coexisting malignant tumors;(6) arterial embolism within 6 months, such as angina pectoris, myocardial infarction, and cerebrovascular accident; and (7) comorbidities or mental health abnormalities that could affect patients' participation in the study. Patients were eliminated from the study if: (1) radical gastrectomy could not be completed; (2) end-to-side esophagojejunal anastomosis was not performed during the procedure; or (3) esophagojejunal anastomosis reinforcement was not possible. Double and a half layered esophagojejunal anastomosis was performed as follows: (1) Open surgery: the full thickness of the anastomosis is continuously sutured, followed by embedding the seromuscular layer with barbed or 3-0 absorbable sutures. The anastomosis is sutured with an average of six to eight stitches. (2) Laparoscopic surgery: the anastomosis is strengthened by counterclockwise full-layer sutures. Once the anastomosis has been sutured to the right posterior aspect of the anastomosis, the jejunum stump is pulled to the right and the anastomosis turned over to continue to complete reinforcement of the posterior wall. The suture interval is approximately 5 mm. After completing the full-thickness suture, the anastomosis is embedded in the seromuscular layer. Relevant data of patients who had undergone radical gastrectomy in the above 12 centers from June 2021 were collected and analyzed. The primary outcome was safety (e.g., postoperative complications, and treatment). Other studied variables included details of surgery (e.g., surgery time, intraoperative bleeding), postoperative recovery (postoperative time to passing flatus and oral intake, length of hospital stay), and follow-up conditions (quality of life as assessed by Visick scores).Result:[1] From June 2021 to September 2022,457 patients were enrolled, including 355 men and 102 women of median age 60.8±10.1 years and BMI 23.7±3.2 kg/m2. The tumors were located in the upper stomach in 294 patients, mid stomach in 139; and lower stomach in 24. The surgical procedures comprised 48 proximal gastrectomies and 409 total gastrectomies. Neoadjuvant chemotherapy was administered to 85 patients. Other organs were resected in 85 patients. The maximum tumor diameter was 4.3±2.2 cm, number of excised lymph nodes 28.3±15.2, and number of positive lymph nodes five (range one to four. As to pathological stage,83 patients had Stage I disease, 128 Stage II, 237 Stage III, and nine Stage IV. [2] The studied surgery-related variables were as follows: The operation was successfully completed in all patients, 352 via a transabdominal approach, 25 via a transhiatus approach, and 80 via a transthoracoabdominal approach. The whole procedure was performed laparoscopically in 53 patients (11.6%), 189 (41.4%) underwent laparoscopic-assisted surgery, and 215 (47.0%) underwent open surgery. The median intraoperative blood loss was 200 (range, 10–1 350) mL, and the operating time 215.6±66.7 minutes. The anastomotic reinforcement time was 2 (7.3±3.9) minutes for laparoscopic-assisted surgery, 17.6±1.7 minutes for total laparoscopy, and 6.0±1.2 minutes for open surgery. [3] The studied postoperative variables were as follows: The median time to postoperative passage of flatus was 3.1±1.1 days and the postoperative gastrointestinal angiography time 6 (range, 4–13) days. The median time to postoperative oral intake was 7 (range, 2–14) days, and the postoperative hospitalization time 15.8±6.7 days. [4] The safety-related variables were as follows: In total, there were 184 (40.3%) postoperative complications. These comprised esophagojejunal anastomosis complications in 10 patients (2.2%), four (0.9%) being anastomotic leakage (including two cases of subclinical leakage and two of clinical leakage; all resolved with conservative treatment); and six patients (1.3%) with anastomotic stenosis (two who underwent endoscopic balloon dilation 21 and 46 days after surgery, the others improved after a change in diet). There was no anastomotic bleeding. Non-anastomotic complications occurred in 174 patients (38.1%). All patients attended for follow-up at least once, the median follow-up time being 10 (3–18) months. Visick grades were as follows: Class I, 89.1% (407/457); Class II, 7.9% (36/457); Class III, 2.6% (12/457); and Class IV 0.4% (2/457).Conclusion:Double and a half layered esophagojejunal anastomosis in radical gastrectomy is safe and feasible.

Objective:To evaluate the safety of double and a half layered esophagojejunal anastomosis in radical gastrectomy.Methods:This prospective, multi-center, single-arm study was initiated by the Affiliated Cancer Hospital of Zhengzhou University in June 2021 (CRAFT Study, NCT05282563). Participating institutions included Nanyang Central Hospital, Zhumadian Central Hospital, Luoyang Central Hospital, First Affiliated Hospital of Henan Polytechnic University, First Affiliated Hospital of Henan University, Luohe Central Hospital, the People's Hospital of Hebi, First People's Hospital of Shangqiu, Anyang Tumor Hospital, First People's Hospital of Pingdingshan, and Zhengzhou Central Hospital Affiliated to Zhengzhou University. Inclusion criteria were as follows: (1) gastric adenocarcinoma confirmed by preoperative gastroscopy;(2) preoperative imaging assessment indicated that R0 resection was feasible; (3) preoperative assessment showed no contraindications to surgery;(4) esophagojejunostomy planned during the procedure; (5) patients volunteered to participate in this study and gave their written informed consent; (6) ECOG score 0–1; and (7) ASA score I–III. Exclusion criteria were as follows: (1) history of upper abdominal surgery (except laparoscopic cholecystectomy);(2) history of gastric surgery (except endoscopic submucosal dissection and endoscopic mucosal resection); (3) pregnancy or lactation;(4) emergency surgery for gastric cancer-related complications (perforation, hemorrhage, obstruction); (5) other malignant tumors within 5 years or coexisting malignant tumors;(6) arterial embolism within 6 months, such as angina pectoris, myocardial infarction, and cerebrovascular accident; and (7) comorbidities or mental health abnormalities that could affect patients' participation in the study. Patients were eliminated from the study if: (1) radical gastrectomy could not be completed; (2) end-to-side esophagojejunal anastomosis was not performed during the procedure; or (3) esophagojejunal anastomosis reinforcement was not possible. Double and a half layered esophagojejunal anastomosis was performed as follows: (1) Open surgery: the full thickness of the anastomosis is continuously sutured, followed by embedding the seromuscular layer with barbed or 3-0 absorbable sutures. The anastomosis is sutured with an average of six to eight stitches. (2) Laparoscopic surgery: the anastomosis is strengthened by counterclockwise full-layer sutures. Once the anastomosis has been sutured to the right posterior aspect of the anastomosis, the jejunum stump is pulled to the right and the anastomosis turned over to continue to complete reinforcement of the posterior wall. The suture interval is approximately 5 mm. After completing the full-thickness suture, the anastomosis is embedded in the seromuscular layer. Relevant data of patients who had undergone radical gastrectomy in the above 12 centers from June 2021 were collected and analyzed. The primary outcome was safety (e.g., postoperative complications, and treatment). Other studied variables included details of surgery (e.g., surgery time, intraoperative bleeding), postoperative recovery (postoperative time to passing flatus and oral intake, length of hospital stay), and follow-up conditions (quality of life as assessed by Visick scores).Result:[1] From June 2021 to September 2022,457 patients were enrolled, including 355 men and 102 women of median age 60.8±10.1 years and BMI 23.7±3.2 kg/m2. The tumors were located in the upper stomach in 294 patients, mid stomach in 139; and lower stomach in 24. The surgical procedures comprised 48 proximal gastrectomies and 409 total gastrectomies. Neoadjuvant chemotherapy was administered to 85 patients. Other organs were resected in 85 patients. The maximum tumor diameter was 4.3±2.2 cm, number of excised lymph nodes 28.3±15.2, and number of positive lymph nodes five (range one to four. As to pathological stage,83 patients had Stage I disease, 128 Stage II, 237 Stage III, and nine Stage IV. [2] The studied surgery-related variables were as follows: The operation was successfully completed in all patients, 352 via a transabdominal approach, 25 via a transhiatus approach, and 80 via a transthoracoabdominal approach. The whole procedure was performed laparoscopically in 53 patients (11.6%), 189 (41.4%) underwent laparoscopic-assisted surgery, and 215 (47.0%) underwent open surgery. The median intraoperative blood loss was 200 (range, 10–1 350) mL, and the operating time 215.6±66.7 minutes. The anastomotic reinforcement time was 2 (7.3±3.9) minutes for laparoscopic-assisted surgery, 17.6±1.7 minutes for total laparoscopy, and 6.0±1.2 minutes for open surgery. [3] The studied postoperative variables were as follows: The median time to postoperative passage of flatus was 3.1±1.1 days and the postoperative gastrointestinal angiography time 6 (range, 4–13) days. The median time to postoperative oral intake was 7 (range, 2–14) days, and the postoperative hospitalization time 15.8±6.7 days. [4] The safety-related variables were as follows: In total, there were 184 (40.3%) postoperative complications. These comprised esophagojejunal anastomosis complications in 10 patients (2.2%), four (0.9%) being anastomotic leakage (including two cases of subclinical leakage and two of clinical leakage; all resolved with conservative treatment); and six patients (1.3%) with anastomotic stenosis (two who underwent endoscopic balloon dilation 21 and 46 days after surgery, the others improved after a change in diet). There was no anastomotic bleeding. Non-anastomotic complications occurred in 174 patients (38.1%). All patients attended for follow-up at least once, the median follow-up time being 10 (3–18) months. Visick grades were as follows: Class I, 89.1% (407/457); Class II, 7.9% (36/457); Class III, 2.6% (12/457); and Class IV 0.4% (2/457).Conclusion:Double and a half layered esophagojejunal anastomosis in radical gastrectomy is safe and feasible.

Objective:To explore the effects of free gracilis muscle flap combined with sural nerve transfer for reconstruction of digital flexion and sensory function of hand in patient with severe wrist electric burn.Methods:A retrospective observational study was conducted. From January 2017 to December 2020, 4 patients with wrist high-voltage electric burn admitted to the Department of Burns of the First People's Hospital of Zhengzhou and 4 patients with wrist high-voltage electric burn admitted to the Department of Hand Surgery of Beijing Jishuitan Hospital met the inclusion criteria, including 6 males and 2 females, aged 12 to 52 years. They were all classified as type Ⅱ wrist high-voltage electric burns with median nerve defect. In the first stage, the wounds were repaired with free anterolateral thigh femoral myocutaneous flap. In the second stage, the free gracilis muscle flap combined with sural nerve transplantation was used to reconstruct the digital flexion and sensory function of the affected hand in 3 to 6 months after wound healing. The cut lengths of muscle flap and nerve were 32 to 38 and 28 to 36 cm, respectively. The muscle flap donor area and nerve donor area were both closed and sutured. The survival condition of gracilis muscle flap and sural nerve, the wound healing time of recipient area on forearm, the healing time of suture in muscle flap donor area and nerve donor area were observed and recorded after operation, and the recovery of donor and recipient areas was followed up. In 2 years after operation, the muscle strength of thumb and digital flexion and finger sensory function after the hand function reconstruction were evaluated with the evaluation criteria of the hand tendon and nerve repair in the trial standard for the evaluation of functions of upper limbs of Hand Surgery Society of Chinese Medical Association.Results:All the gracilis muscle flap and sural nerve survived successfully after operation. The wound healing time of recipient area on forearm was 10 to 14 days after operation, and the healing time of suture in muscle flap donor area and nerve donor area was 12 to 15 days after operation. The donor and recipient areas recovered well. In the follow-up of 2 years after operation, the muscle strength of thumb and digital flexion was evaluated as follows: 4 cases of grade 5, 3 cases of grade 4, and 1 case of grade 2; the finger sensory function was evaluated as follows: 4 cases of grade S3 +, 2 cases of grade S3, and 2 cases of grade S2. Conclusions:For patients with hand dysfunction caused by severe wrist electric burn, free gracilis muscle flap combined with sural nerve transplantation can be used to reconstruct the digital flexion and sensory function of the affected hand. It is a good repair method, which does not cause great damage to thigh muscle flap donor area or calf nerve donor area.

Objective:To explore the clinical effects of scalp flaps pedicled with superficial temporal artery parietal branch in repairing facial destructive burn wounds.Methods:A retrospective observational study was conducted. From January 2016 to December 2021, 15 patients with facial destructive burns who met the inclusion criteria were admitted to Zhengzhou First People's Hospital, including 11 males and 4 females, aged 22 to 79 years. Two patients were complicated with unilateral eyeball destructive burns, two patients were complicated with unilateral auricle defects, eight patients were complicated with lip and cheek defects, and three patients were complicated with lip, cheek, and unilateral nasal alar defects. The burn wound areas ranged from 9 cm×6 cm to 13 cm×10 cm. The scalp flaps pedicled with superficial temporal artery parietal branch, with the area of 10 cm×7 cm to 15 cm×11 cm, were designed, excised, and transferred for repairing burn wounds. The secondary wounds at the donor sites were repaired with medium-thickness scalp grafts. According to patient's needs, the hairs grew at the facial transplanted flap were removed by laser at 2 weeks after the flap was completely viable, or the expanded scalp flap was used to treat the secondary alopecia in the flap donor area of the head at 3 months after the primary wound repair. The survival of the flap/skin graft and the wound healing of the donor and recipient areas after the primary wound repair were recorded. During the follow-up, the appearance of the flap, the scar hyperplasia at the suture site, the repair effect of facial functional parts, the treatment effects of laser hair removal and secondary alopecia treatment at the flap donor site were observed; the patient's satisfaction with the overall repair effect was inquired.Results:After the primary wound repair, all the flaps transplanted to the burn wounds and the skin grafts transplanted to the secondary wounds of the flap donor sites survived well, and the wounds at the donor and recipient sites of flap healed well. The color, texture, and thickness of flap were basically the same as those of normal facial skin, and the scar at the suture site was slight during 3 to 18 months of follow-up period after the primary wound repair. In 11 patients complicated with lip defects, the oral integrity, and the opening and closing functions of mouth were restored with the mouth opening being 2.0-2.5 cm and no microstomia; all the patients could carry out basic language communication, 8 of them could take regular food, and 3 of them could take soft food. The wounds in two patients with unilateral eyeball destructive burns were repaired. In 2 patients complicated with auricle defects, the wounds were repaired, and the external auditory canals were normal. In 3 patients complicated with unilateral nasal alar defects, their noses had poor appearance with reduced nostrils. No hair growth was observed in the facial flap sites after treatment of laser hair removal in 8 patients. Five patients were successfully treated with expanded scalp flaps for secondary alopecia in the flap donor area of the head. The patients were all satisfied with the overall repair effect.Conclusions:The scalp flap pedicled with superficial temporal artery parietal branch has abundant blood supply and is suitable for repairing the wounds in facial destructive burns. It is easy to transfer and can better restore the appearance and function of the recipient area with minimal damage to the flap donor area, which is worthy of clinical promotion.

Objective:To discuss the long-term survival and risk factors of thyroid cancer in the real world in China.Methods:The clinical data of thyroid cancer patients who underwent initial surgery from Apr. 1998 to Dec. 2018 were retrospectively analyzed, including patients’sex, age, surgical records, pathology, hospitalization records and follow-up. According to the prognosis, the patients were divided into disease-free survival group and recurrence/metastasis/death group. Univariate analysis and multivariate regression analysis were conducted to analyze the risk factors affecting the prognosis of thyroid cancer. The clinical features and prognostic risk factors of thyroid cancer patients were investigated.Results:A total of 2038 cases were collected, and the longest follow-up time was more than 20 years. A total of 1876 cases were included in the study, 162 cases were lost, and the rate of follow-up was 7.9%. Among them, 1858 survived, the overall survival rate was 99.04%; 18 died, and the overall mortality rate was 0.96%. According to the prognosis of thyroid cancer, the patients were divided into 2 groups, including 1808 cases in the disease-free survival group and 68 cases in the relapsed-metastatic-death group. The study found that there were statistical differences between the two groups in terms of patients’age [ (45.40±11.016) vs (51.53±15.199, P=0.000) , the male ratio (32.854%, 48.529%, P=0.001) , whether tumor breaks through capsule (20.077%, 33.823%, P=0.006) , central lymph node metastasis (48.834%, 70.588%, P=0.001) and lateral lymph node metastasis (31.084%, 55.882%, P=0.000) , and there was no difference between the number of tumor lesions. Conclusion:Thyroid cancer has a good prognosis, but according to the characteristics of patients with thyroid cancer in my country, it should still be treated early in the clinic, and the standardization and thoroughness of surgery should be adhered to during the treatment.

Objective:To study the effect of thermal effect on the filling effect of bioceramic paste combined with thermal gel gutta-percha vertical obturation method in different parts of root canal.Methods:Forty single-root canal teeth samples were randomly and randomized divided into the control group, the iRoot SP group, the 10 s group and the 20 s group. All tooth samples were root canal prepared to 0.04 taper after crown removal. The control group received AH-plus paste combined with thermal gel gutta-percha vertical obturation. The iRoot SP group received iRoot SP single-point filling. The 10 s group and 20 s group received iRoot SP single-point filling combined with thermal gel gutta-percha vertical obturation, in which the root canal of the two groups were heated at 180 °C for 10 s and 20 s, respectively, before using the thermosetting gutta-percha. Methylene blue staining, scanning electron microscope (SEM) observation and dental microscope observation were used to analyze the occurrence of gaps in the middle and upper segment of the root canal and the apical 1/3 of the root canal after filling.Results:For the filling in the apical 1/3 of the root canal, no obvious gap appeared in the 10 s group and the 20 s group, and there was no significant difference between the dye infection depth and the control group (all P>0.05). For the filling of the middle and upper segment of the root canal, the probability of porosity is higher when using iRoot SP combined with single-point filling. Conclusions:Short-term high temperature heating will not affect the sealing effect of iRoot SP on the apical 1/3 of the root canal. For the middle and upper segment of the root canal, the filling effect of iRoot SP single-point filling combined with thermal gel gutta-percha vertical obturation method is better than that of iRoot SP single-point filling.