Objective:In this retrospective study, the accuracy and outcomes of segmental Le Fort I surgery with the aid of 3D-printed surgical templates and occlusal splints and dental model surgery were evaluated.Methods:Clinical data of patients receiving segmental Le Fort I surgery in the Department of Orthognathic and Temporo-Mandibular Joint Surgery of West China Stomatological Hospital of Sichuan University from January 2014 to June 2019 were retrospectively analyzed. The accuracy of virtual surgical planning(VSP) and the difference between VSP and dental model surgery were evaluated by postoperative complications, color distance maps, and quantitative accuracy analysis.The amount of surgical displacement of the maxilla in the three-dimensional direction before and after surgery, the occurrence of postoperative complications and the patients'satisfaction survey were analyzed in both groups. Paired t-tests were used for the linear distance and angle between the preoperative design model and the final virtual surgery model in the digital surgery group. Independent samples t-test was used for each marker point’s preoperative and postoperative displacements in the three-dimensional direction between the digital surgery group and the dental model group. The proportion of postoperative complications in the 2 groups was tested using the Pearson chi-square test, and the difference was considered statistically significant at P<0.05. Results:There were 129 patients in the digital surgery group, 35 males and 94 females, aged (24.5±6.5) years, and 92 patients in the dental model surgery group, 28 males and 64 females, aged (27.7±5.4) years.The overall mean linear difference was 1.23±0.35 mm, and the overall mean angular difference was 2.48°±0.31°. The vertical displacement of U3R, U6L in the digital surgery group was (6.72±1.57)mm and (4.73±2.07)mm. The vertical displacement of U3R, U6L in the group of dental model surgery was (4.07±2.14)mm and (1.62±1.82)mm.The significant deviation difference in U3R-Y and U6L-Y between two groups could be detected. The complications in two groups showed a significant difference. Except for one case of root injury, there was no serious complication recorded in the digital surgery group. However, there were three cases of palatal fistulas, four cases of root injury and two cases of bone dehiscence in the dental model group. 94.5% of patients in the digital surgery group are satisfied with the surgical results, while 89.1% in the dental model group.Conclusion:Compared with dental model surgery, segmental Le Fort I surgery is highly accurate under the guidance of surgical templates and occlusal splint which has better postoperative results and effectively reduces the occurrence of surgical complications.

Objective:In this retrospective study, the accuracy and outcomes of segmental Le Fort I surgery with the aid of 3D-printed surgical templates and occlusal splints and dental model surgery were evaluated.Methods:Clinical data of patients receiving segmental Le Fort I surgery in the Department of Orthognathic and Temporo-Mandibular Joint Surgery of West China Stomatological Hospital of Sichuan University from January 2014 to June 2019 were retrospectively analyzed. The accuracy of virtual surgical planning(VSP) and the difference between VSP and dental model surgery were evaluated by postoperative complications, color distance maps, and quantitative accuracy analysis.The amount of surgical displacement of the maxilla in the three-dimensional direction before and after surgery, the occurrence of postoperative complications and the patients'satisfaction survey were analyzed in both groups. Paired t-tests were used for the linear distance and angle between the preoperative design model and the final virtual surgery model in the digital surgery group. Independent samples t-test was used for each marker point’s preoperative and postoperative displacements in the three-dimensional direction between the digital surgery group and the dental model group. The proportion of postoperative complications in the 2 groups was tested using the Pearson chi-square test, and the difference was considered statistically significant at P<0.05. Results:There were 129 patients in the digital surgery group, 35 males and 94 females, aged (24.5±6.5) years, and 92 patients in the dental model surgery group, 28 males and 64 females, aged (27.7±5.4) years.The overall mean linear difference was 1.23±0.35 mm, and the overall mean angular difference was 2.48°±0.31°. The vertical displacement of U3R, U6L in the digital surgery group was (6.72±1.57)mm and (4.73±2.07)mm. The vertical displacement of U3R, U6L in the group of dental model surgery was (4.07±2.14)mm and (1.62±1.82)mm.The significant deviation difference in U3R-Y and U6L-Y between two groups could be detected. The complications in two groups showed a significant difference. Except for one case of root injury, there was no serious complication recorded in the digital surgery group. However, there were three cases of palatal fistulas, four cases of root injury and two cases of bone dehiscence in the dental model group. 94.5% of patients in the digital surgery group are satisfied with the surgical results, while 89.1% in the dental model group.Conclusion:Compared with dental model surgery, segmental Le Fort I surgery is highly accurate under the guidance of surgical templates and occlusal splint which has better postoperative results and effectively reduces the occurrence of surgical complications.

Objective:To explore the hematological phenotype and genotypic characteristics of five Chinese individuals with a rare thalassemia mutation HBB: c. 93-21G>A. Methods:A retrospective study was carried out on five individuals identified by the People′s Hospital of Yangjiang and Guangzhou Hybribio Co., Ltd. from May 2018 to September 2022. Routine blood test and hemoglobin electrophoresis were performed, and the genotypes of five subjects were determined by using PCR combined with reverse dot blotting (RDB), nested PCR, Gap-PCR and Sanger sequencing. This study was approved by Medical Ethics Cornmittee of the People′s Hospital of Yangjiang (Ethics No. 20240001).Results:Among the five individuals, hematological data of one was unavailable, and the remaining four had presented with microcytosis and hypochromia. The results of hemoglobin electrophoresis indicated that all of them had a HbA 2 level of &ge;4.7%. Genetic analysis showed that one case had harbored compound heterozygous mutations of ααα anti3.7 triplet and HBB: c. 93-21G>A, one had compound heterozygous mutations of -α 3.7 and HBB: c. 93-21G>A, whilst the remaining three were heterozygous for the HBB: c. 93-21G>A mutation. Conclusion:The hematological phenotype of β-thalassemia carriers ( HBB: c. 93-21G>A) is similar to that of other β + thalassemia heterozygotes with mild β-thalassemia characteristics.