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RECONSTRUCTION OF ORAL MUCODEFECTS WITH BUCCAL FAT PAD FLAP

Objective To evaluate the clinical outcome of the buccal fat pad flap in reconstruction of defects of the oral mucosa. Methods From May 1998 to July 2004, 42 patients with oral mucodefects were treated with buccal fat pad flap. Of them, there were 26 males and 16 females, aging 25-76 years. The defect was caused by buccal squamous carcinoma in 7 cases, by buccal leukoplakia in 5 cases, by squamous carcinoma of soft palate in 7 cases, by adenoid cystic carcinoma of palate in 8 cases, by carcinoma of maxillary sinus in 6 cases, by maxillo-alveolar angioma in 5 cases and by keratocyst of maxilla in 4 cases. The locations were buccal mucosa, maxillary sinus and soft palate. The size of defect ranged from 3.0 cm×3.0 cm to 6.5 cm×4.0cm.Results Forty-one cases achieved healing by first intention, except one case because of large defect. Edema faded and epithelization occurred after 4 weeks of operation. Complete epithelization was observed after 6 weeks of operation. Thirty-five cases were followed up 3 months to 5 years. Therewere no obvious differences in layers, color, elasticity, and texture between repaired region and adjacent mucosa. Conclusion The buccal fat pad flap is useful in reconstructing the muco-defects (less than 6.5 cm in diameter) of the posterior maxilla and buccal region without considerable complication. The multiplex blood supply, facility in accessing and minimal donor site morbidity make it a reliable soft tissue graft. The main shortcoming is its limited size.

RECONSTRUCTION OF SOFT TISSUE DEFECTS IN ORAL AND MAXILLOFACIAL REGIONS AFTER TUMORS SURGERY USING CERVICAL PEDICLE TISSUE FLAPS

Objective To report 4 methods of reconstructing soft tissue defects in oral and maxillofacial regions after tumors resection using cervical pedicle tissue flaps. Methods One hundred seventy-two soft tissue defects were repaired with cervical myocutaneous flaps after resection of oral and facial cancer( 165 cases of squamous cell carcinoma and 7 cases of salivary carcinoma). The clinical stage of the tumors was stage Ⅰ in 21 cases, stage Ⅱ in 116 cases and stage Ⅲin 35 cases. Primary sites of the lesions were the tongue (59 cases), buccal mucosa (55 cases), lower gingiva (26 cases), floor of the mouth (25 cases), parotid gland (4 cases) and oropharynx (3 cases). Infrahyoid myocutaneous flaps were used in 60 cases, platysma flaps in 45 cases, sternocleidomastoid flaps in 59 cases and submental island flaps in 8 cases. The sizes of skin paddle ranged from 2.5 cm×5.0 cm to 5.0 cm ×8.0 cm. Results Among 153 survival flaps, there were55 infrahyoid myocutaneous flaps, 40 platysma flaps, 52 sternocleidomastoid flaps and 6 submental island flaps. There were 11 cases of total flap necrosis and8 cases of partial flap necrosis. The success rates were 91.67%(55/60) for infrahyoid myocutaneous flap, 88.89%(40/45) for platysma flap, 88.14% (52/59) for sternocleidomastoid flap and 75%(6/8) for submental island flap. After a follow-up of 3 11 years(5.7 years on average) among 101 cases local reccurence in 18 cases, cervical reccurence in 4 cases, distance metastasis in 2 cases. The survical rate at 3 years were 83.17%(84/101). Conclusion Cervical pedicle tissue flaps haveclinical value in reconstruction of small and medium-sized soft tissue defects after resection of oral and maxillofacial tumors.

胸大肌肌皮瓣修复口腔颌面部肿瘤切除后的缺损

Effects of different alveolar bone finite element models on the biomechanical responses of periodontal ligament

In the study of oral orthodontics, the dental tissue models play an important role in finite element analysis results. Currently, the commonly used alveolar bone models mainly have two kinds: the uniform and the non-uniform models. The material of the uniform model was defined with the whole alveolar bone, and each mesh element has a uniform mechanical property. While the material of the elements in non-uniform model was differently determined by the Hounsfield unit (HU) value of computed tomography (CT) images where the element was located. To investigate the effects of different alveolar bone models on the biomechanical responses of periodontal ligament (PDL), a clinical patient was chosen as the research object, his mandibular canine, PDL and two kinds of alveolar bone models were constructed, and intrusive force of 1 N and moment of 2 Nmm were exerted on the canine along its root direction, respectively, which were used to analyze the hydrostatic stress and the maximal logarithmic principal strain of PDL under different loads. Research results indicated that the mechanical responses of PDL had been affected by alveolar bone models, no matter the canine translation or rotation. Compared to the uniform model, if the alveolar bone was defined as the non-uniform model, the maximal stress and strain of PDL were decreased by 13.13% and 35.57%, respectively, when the canine translation along its root direction; while the maximal stress and strain of PDL were decreased by 19.55% and 35.64%, respectively, when the canine rotation along its root direction. The uniform alveolar bone model will induce orthodontists to choose a smaller orthodontic force. The non-uniform alveolar bone model can better reflect the differences of bone characteristics in the real alveolar bone, and more conducive to obtain accurate analysis results.

Evidence-Based Purchasing of Oral and Dental Technical Equipment

Oral panorama reconstruction method based on pre-segmentation and Bezier function

For patients with partial jaw defects, cysts and dental implants, doctors need to take panoramic X-ray films or manually draw dental arch lines to generate Panorama images in order to observe their complete dentition information during oral diagnosis. In order to solve the problems of additional burden for patients to take panoramic X-ray films and time-consuming issue for doctors to manually segment dental arch lines, this paper proposes an automatic panorama reconstruction method based on cone beam computerized tomography (CBCT). The V-network (VNet) is used to pre-segment the teeth and the background to generate the corresponding binary image, and then the Bezier curve is used to define the best dental arch curve to generate the oral panorama. In addition, this research also addressed the issues of mistakenly recognizing the teeth and jaws as dental arches, incomplete coverage of the dental arch area by the generated dental arch lines, and low robustness, providing intelligent methods for dental diagnosis and improve the work efficiency of doctors.

Efficacy comparison of transoral endoscopic thyroidectomy vestibular approach vs conventional open thyroidectomy for differentiated thyroid carcinoma: a meta-analysis

ObjectiveTo systematically evaluate the reliability and stability of transoral endoscopic thyroidectomy vestibular approach (TOETVA) and conventional open thyroidectomy (COT) in the treatment of differentiated thyroid cancer.MethodsThe clinical studies of TOETVA and COT in the treatment of differentiated thyroid cancer were retrieved from major databases including PubMed, Embase, Cochrane Library, Wanfang, and CNKI by computer. The search date ended on March 1, 2020. Two investigators screened the literatures strictly and extracted the data following the pre-defined inclusion and exclusion criteria, and then used RevMan 5.3 software for meta-analysis.ResultsA total of 7 studies including 1 465 patients were included in this meta-analysis. The results showed: compared with the COT group, the operation time of the TOETVA group was longer [WMD=35.18, P=0.000 1], and the number of lymph node dissections in the central area was larger [WMD=1.42, P=0.000 5]. But the intraoperative blood loss [WMD=–5.32, P=0.39], the length of hospital stay after operation [WMD=0.05, P=0.94], the incidences of transient recurrent laryngeal nerve palsy [OR=0.81, P=0.43], transient hypocalcemia [OR=0.55, P=0.35], permanent hypocalcemia [OR=0.39, P=0.22], permanent recurrent laryngeal nerve palsy [OR=1.34, P=0.73], and hematoma [OR=1.29, P=0.69] were not statistically significant between the two groups.ConclusionsTOETVA has a higher stability. Although the COT has a shorter operation time, the former has a higher central lymph node dissection rate, and there is no scar on the neck after surgery and no significant difference in the incidence of postoperative complications.

Accuracy of computer-guided oral implant placement and influencing factors

With the development of computer and digital technology, the application of computer-aided technology has become a new trend in the field of oral implant. Computer-guided oral implant surgery has the advantages of being safer and more accurate than traditional implant surgery, and it can truly realize the concept of restoration-oriented implant. However, computer-guided oral implant surgery has various steps which cause deviations accumulation, so that some clinicians remain sceptical about the accuracy of the technology. Currently, due to the lack of a quantitative system for evaluating the accuracy of computer-guided oral implantation, the implant deviation in each step is still inconclusively in the stage of research and debate. The purpose of this paper is to summarize the advantages and disadvantages, research progress, accuracy and influencing factors of computer-guided oral implantation, aiming to provide a reference for improving implant accuracy and guiding clinical design and surgery.

规律含漱对喉癌术后口腔pH值及口咽细菌的影响

目的探讨采用复方氯己定漱口液规律含漱对喉癌术后口腔pH值及口咽细菌的影响。 方法选择2011年5月－2012年10月收治的71例患者，按住院日期单双号分为观察组35例（单号），对照组36例（双号），对照组给予常规口腔护理2次/d，观察组在此基础上配合复方氯己定漱口液规律含漱，即术后每天07：00、11：00、12：00、16：00、20：00、22：00各含漱10 min。 结果术后第8天，观察组口腔pH值为（6.84±0.52）明显较对照组（5.37±0.62）趋于正常范围，组间比较差异有统计学意义（t=10.809，P=0.000）；观察组口咽细菌阳性2例，阳性检出率仅为5.71%，明显低于对照组阳性检出率27.78%，差异有统计学意义（χ2=6.151，P=0.013）；观察组并发症总发率为11.43%，对照组并发症总发生率为41.67%，两组口腔并发症发生率差异有统计学意义（χ2=8.279，P=0.004）。 结论采用复方氯己定含漱液进行规律漱口，能纠正口腔pH值，减轻口腔发生菌群繁殖，预防口腔并发症的发生，促进患者术后康复。

PRIMARY GRAFTING RESEARCH OF TISSUE ENGINEERED ORAL MUCOSA LAMINA PROPRIA ON SKIN FULL THICKNESS WOUNDS

Objective To study the allograft effect of two kinds of tissue engineered oral mucosa lamina proprias on skin fullthickness wounds. Methods The cultured Wistar rat oral mucosa fibroblasts (OMF) were incorporated into collag en or chitosancollagen to construct the tissue engineered oral mucosa laminaproprias, and then the OMFs were labeled with BrdU. The fullthickness round skin defects were made with a round knife (diameter, 0.8 cm) on the backs of 36 Wistar rats (2125 weeks old), which were divided into 2 experimental groups: the fibroblastpopulated collagen lattices (FPCL) group (grafted by FPCLs) and the fibroblastpopulated chitosan collagen lattices (FPCCL) group (grafted by FPCCLs), and the control group (only covered with gauges). All the wounds were observed by the naked eyes or the light microscope, and were measured 4, 7, 14, and 21 days postoperatively. Results There were no infection during the wound healing period. At 7 days after the grafting, the wounds in the 3 groups were covered by scab and/or gauze; at 14 days, the gauze and scab on the wounds in the three groups were all replaced by the new epidermis naturally except one scab each in the FPCCL group and the control groups,which was replaced at 17 days.All the centers of the new epidermis were measurable as the pink red points. At 21 days, all the new skins were smooth without hairs, and their color was similar to the normal one. At 4, 7, and 14 days,there was an indication that the wound diameters became significantly smaller in the three groups; but after the 14th day, there was no significant indication of this kind. At 7 days, the wound diameter in the FPCL group was significantly smaller than that in the FPCCL group and the control group (Plt;0.01). Under the lightmicroscope, at 4 days postoperatively, the decayed tissue on the surfaces of the recipient wounds in the FPCL group and the FPCCL group was separated from the lower granular tissue in which there were many inflammatory cells, fibroblasts, and new vessels. There was a similar-phenomenon in the control group. Each skin wound in the three groups was only partly keratinocyted at 7 days postoperativel y. The recipient wounds were wholly keratinocyted with when rete ridges observed at 14 and 21 days, but in the control group the wounds were keratinocyted with no rete ridges. Fibers in the new dermis were thin. The OMFs with Brdu appeared in the granular tissue and new dermis at 4, 7, 14, and 21 days postoperatively, which could be illustr ated by the immunohistochemical staining. The positive OMFs and the granular tissue joined in the repair of the skin defe cts without any allergic reaction during the period of the wound healing. Conclusion The oral mucosa fibroblasts as the new seed cells can join i n the repair of the skin defects effectively and feasibly. The fibroblastpopul ated collagen lattices and the fibroblastpopulated chitosan collagen lat tices can repair skin defects effectively and feasibly, too. And the quality of the new skins was better in the two experimental groups than in the control group.