Long-term changes in mandibular bone microchemical quality after radiation therapy and underlying systemic malignancy:A pilot study

Radiation therapy(RT)is a treatment option for head and neck cancer(HNC),but 2%of RT patients may experience damage to the jawbone,resulting in osteoradionecrosis(ORN).The ORN can manifest years after RT exposure.Changes in the local microchemical bone quality prior to the clinical manifestation of ORN could play a key role in ORN pathogenesis.Chemical bone quality can be analyzed using Fourier transform infrared spectroscopy(FTIR),that is applied to examine the effects of cancer,chemotherapy,and RT on the quality of human man-dibular bone.Cortical mandibular bone samples were harvested from dental implant beds of 23 individuals,i.e.,patients with surgically and radiotherapeutically treated HNC(RT-HNC,n=7),surgically and radiochemotherapeutically treated HNC(CH-RT-HNC,n=3),only surgically treated HNC(SRG-HNC,n=4),and healthy controls(n=9).Infrared spectra were acquired from two representative regions of interest in cortical mandibular bone.Spectral parameters,i.e.,mineral-to-matrix ratio(MM),carbonate-to-matrix ratio(CM),carbonate-to-phosphate ratio(CP),collagen maturity(cross-linking),crystallinity,acid phosphate substitu-tion(APS),and advanced glycation end products(AGEs),were analyzed for each sample.Amide I region of the CH-RT-HNC group differed from the control group in cluster analysis(p=0.02).Apart from a minor variation trend in collagen maturity(p=0.07),there were no other signif-icant differences between the groups.Thus,the effect of radiochemotherapy on mandibular bone composition should be further investigated.In future trials,this study design is potential when the effects of the cancer burden and different HNC treatment modalities on jawbone composition are studied,in order to reveal ORN pathogenesis.

Customized bioceramic scaffolds and metal meshes for challenging large-size mandibular bone defect regeneration and repair

Large-size mandible graft has huge needs in clinic caused by infection,tumor,congenital deformity,bone trauma and so on.However,the reconstruction of large-size mandible defect is challenged due to its complex anatomical structure and large-range bone injury.The design and fabrication of porous implants with large segments and specific shapes matching the native mandible remain a considerable challenge.Herein,the 6%Mg-doped calcium silicate(CSi-Mg6)andβ-andα-tricalcium phosphate(β-TCP,α-TCP)bioceramics were fabricated by digital light processing as the porous scaffolds of over 50%in porosity,while the titanium mesh was fabricated by selective laser melting.The mechanical tests showed that the initial flexible/compressive resistance of CSi-Mg6 scaffolds was markedly higher than that ofβ-TCP andα-TCP scaffolds.Cell experiments showed that these materials all had good biocompatibility,while CSi-Mg6 significantly promoted cell proliferation.In the rabbit critically sized mandible bone defects(∼13 mm in length)filled with porous bioceramic scaffolds,the titanium meshes and titanium nails were acted as fixation and load bearing.The results showed that the defects were kept during the observation period in the blank(control)group;in contrast,the osteogenic capability was significantly enhanced in the CSi-Mg6 andα-TCP groups in comparison with theβ-TCP group,and these two groups not only had significantly increased new bone formation but also had thicker trabecular and smaller trabecular spacing.Besides,the CSi-Mg6 andα-TCP groups showed appreciable material biodegradation in the later stage(from 8 to 12 weeks)in comparison with theβ-TCP scaffolds while the CSi-Mg6 group showed much outstanding mechanical capacity in vivo in the early stage compared to theβ-TCP andα-TCP groups.Totally,these findings suggest that the combination of customized strength-strong bioactive CSi-Mg6 scaffolds together with titanium meshes is a promising way for repairing the large-size load-bearing mandible defects.

Correction of mandibular deficiency by inverted-L osteotomy of ramus and iliac crest bone grafting

This study was to describe the use of inverted-L osteotomy of ramus and lilac bone graft for the management of mandibular deficiency in adult patients. From 2008 to 2010, 11 patients （aged 19 to 29 years） with mandibular deficiency underwent intraoral or extraoral inverted-L osteotomy of ramus and lilac crest bone grafting. Data were collected from the patients＇ records, photographs and radiographs. The height and width of the ramus were successfully expanded by inverted-L osteotomy and lilac crest bone grafting with minimal complications in all patients, resulting in significant improvement in occlusion and facial appearance. Our early results showed that the inverted-L osteotomy of ramus and lilac crest bone grafting is safe and effective, and should be considered as a good alternative for the patients with mandibular deficiency.

A hierarchical vascularized engineered bone inspired by intramembranous ossification for mandibular regeneration

Mandibular defects caused by injuries,tumors,and infections are common and can severely affect mandibular function and the patient's appearance.However,mandible reconstruction with a mandibular bionic structure remains challenging.Inspired by the process of intramembranous ossification in mandibular development,a hierarchical vascularized engineered bone consisting of angiogenesis and osteogenesis modules has been produced.Moreover,the hierarchical vascular network and bone structure generated by these hierarchical vascularized engineered bone modules match the particular anatomical structure of the mandible.The ultra-tough polyion complex has been used as the basic scaffold for hierarchical vascularized engineered bone for ensuring better reconstruction of mandible function.According to the results of in vivo experiments,the bone regenerated using hierarchical vascularized engineered bone is similar to the natural mandibular bone in terms of morphology and genomics.The sonic hedgehog signaling pathway is specifically activated in hierarchical vascularized engineered bone,indicating that the new bone in hierarchical vascularized engineered bone underwent a process of intramembranous ossification identical to that of mandible development.Thus,hierarchical vascularized engineered bone has a high potential for clinical application in mandibular defect reconstruction.Moreover,the concept based on developmental processes and bionic structures provides an effective strategy for tissue regeneration.

Healing Mechanism and Osteogenic Capacity of Bovine Bone Mineral—Human Amniotic Mesenchymal Stem Celland Autogenous Bone Graft in Critical Size Mandibular Defect

Experiments on maxillofacial bone tissue engineering showed the promising result;however, its healing mechanisms and effectiveness had not been fully understood. The aim of this study is to compare the bone healing mechanism and osteogenic capacity between bovine bone mineral loaded with hAMSC and autogenous bone graft in the reconstruction of critical size mandibular bone defect. Critical size defects were made at the mandible of 45 New Zealand white rabbits reconstructed with BBM-hAMSC, BBM alone, and ABG, respectively. At the end of first, second, and twelfth weeks, five rabbits from each experimental week were sacrificed for histology and immunohistochemistry staining. Expressions of vascular endothelial growth factor (VEGF), bone mor-phogenic proteins-2 (BMP2), Runx2 and the amount of angiogenesis were analyzed in the first and second week groups, while expressions of Runx2, osteocalcin, collagen type-I fibres, trabecular area and bone incorporation were analyzed in the twelfth week groups. The result showed that expressions of VEGF, BMP2 and Runx2 as well as the amount of angiogenesis were higher in ABG compared with BBM-hAMSC group in the first and second weeks of healing. The result of twelfth week of healing showed that expressions of Runx2 and osteocalcin as well as the thickness of collagen type-I fibres were significantly higher in BBM-hAMSC compared to ABG group, while there was no statistically difference in trabecular area and bone incorporation between BBM-hAMSC and ABG group. This study concluded that early healing activities were higher in auto-genous bone graft than in BBM-hAMSC, while osteogenic activities in the late stage of healing were higher in BBM-hAMSC compared to autogenous bone graft. It was also concluded that the osteo-genic capacity of BBM-hAMSC was comparable to autogenous bone graft in the reconstruction of critical size defect in the mandible.

Hyoid Bone Position as an Etiological Factor in Mandibular Divergence and Morphology

Objectives: The objective is to determine whether there are differences in the position of the hyoid bone at rest in natural head position in subjects with mandibular hyperdivergence and to evaluate whether there are differences in hyoid position and antegonial notch depth in mandibular hyperdivergent males and females. Methods and Materials: This is a retrospective cohort study involving a review of lateral cephalometric radiographs of 45 adult men and women with mandibular hyperdivergency. Hyperdivergency was determined by cephalometric ranges of: SN-GoGn as least +2 SD from normal, Y-axis, PP-GoGN, and gonial angle greater than +1SD from normal. A group of 45 normodivergent adults served as a control, with cephalometric ranges of: SN-GoGn within ±1 SD of normal, with only one measurement of the other three between +1 and +1.5 standard deviations. A custom digital cephalometric analysis, the Hyoid Analysis, was designed, to measure the vertical and horizontal position and inclination of the hyoid and the antegonial notch depth. Results: In hyperdivergent subjects, the posterior aspect of the hyoid is located lower and more posterior, compared to the control group, while there is no difference in position of the anterior surface of the hyoid and the antegonial notch is 0.6 mm deeper. In males, the posterior aspect of hyoid is lower by 8.5 mm, while the anterior surface is located 9.0 mm lower. In males, the hyoid is inclined more steeply than in females by 4.4 degrees and the antegonial notch is deeper than in females by 0.6 mm. Conclusions: There are differences in hyoid bone position and mandibular morphology in hyperdivergent subjects compared to normodivergent subjects and in males compared to females.

Clinical Effect of Resistance-free Removal of the Bone Embedded Mandibular Third Molar

[Objectives] To shorten the time of removal of the bone embedded mandibular third molar,reduce the complications of tooth extraction,and explore a surgery method of resistance-free removal of the mandibular third molar. [Methods] A total of 50 patients with bone embedded mandibular third molar needing to be removed were selected. A 45° elevation turbine and a long tungsten steel drill were used to remove the mesial,buccal,and distal resistances. When necessary,tongue side and root resistance was removed,and the third molar was removed when there was basically no resistance around it. The removal time was recorded,followed up for 10 d,and the postoperative reaction was observed. [Results] The bone embedded mandibular third molars were removed for all patients within 15 min,and there was no serious postoperative reaction,all patients showed high satisfaction. [Conclusions]The method of resistance-free removal of the bone embedded mandibular third molar can significantly shorten the removal time,reduce the fear of patients,and ease pain of patients.

Computer-Assisted Surgery for Mandibular Reconstruction Using a Patient-Specific Titanium Mesh Tray and Particulate Cancellous Bone and Marrow

Craniomaxillofacial surgery is difficult due to the complexity of the regional anatomy. Computer-assisted surgery is a promising tool aiming to improve the safety and precision of such surgery. A computer-assisted surgical navigation approach for reconstruction of mandibular defects using a patient-specific titanium mesh tray and particulate cancellous bone and marrow (PCBM) harvested from bilateral anterior ilia is proposed. This case report involves a large multicystic ameloblastoma affecting the right mandible of a 31-year-old male patient. Following detailed clinical examination, radiological interpretation, and histopathological diagnosis, computer-assisted surgical simulation with a virtual 3-dimensional (3-D) model was designed using surgical planning software based on the pre-operative computed tomography data. Long-span segmental resection of the mandible was planned, and the defect was analyzed for reconstruction using a patient-specific reconstruction titanium mesh tray mediated with computer-aided design and manufacturing (CAD/CAM) techniques. During the actual surgery, the ultrasonic bone cutting instrument in the surgeon’s hand was connected to the navigation system to touch an anatomical position on the patient. Therefore, osteotomies were performed finely and smoothly according to the navigation images of the cutting bone line by sequentially moving the instrument. Finally, a CAD/CAM-mediated titanium mesh tray condensed by PCBM was adapted to the remaining mandibular fragments. Six months postoperatively, the patient had a good mandibular configuration and facial contour. Integration of different technologies, such as software planning and 3-D surgical simulation, combined with intraoperative navigation and CAD/CAM techniques, provides safe and precise mandibular reconstruction surgery.

Early therapeutic effect of platelet-rich fibrin combined with allogeneic bone marrow-derived stem cells on rats’ critical-sized mandibular defects

BACKGROUND Critically sized bone defects represent a significant challenge to orthopaedic surgeons worldwide.These defects generally result from severe trauma or resection of a whole large tumour.Autologous bone grafts are the current gold standard for the reconstruction of such defects.However,due to increased patient morbidity and the need for a second operative site,other lines of treatment should be introduced.To find alternative unconventional therapies to manage such defects,bone tissue engineering using a combination of suitable bioactive factors,cells,and biocompatible scaffolds offers a promising new approach for bone regeneration.AIM To evaluate the healing capacity of platelet-rich fibrin(PRF)membranes seeded with allogeneic mesenchymal bone marrow-derived stem cells(BMSCs)on critically sized mandibular defects in a rat model.METHODS Sixty-three Sprague Dawley rats were subjected to bilateral bone defects of critical size in the mandibles created by a 5-mm diameter trephine bur.Rats were allocated to three equal groups of 21 rats each.Group I bone defects were irrigated with normal saline and designed as negative controls.Defects of group II were grafted with PRF membranes and served as positive controls,while defects of group III were grafted with PRF membranes seeded with allogeneic BMSCs.Seven rats from each group were killed at 1,2 and 4 wk.The mandibles were dissected and prepared for routine haematoxylin and eosin(HE)staining,Masson's trichrome staining and CD68 immunohistochemical staining.RESULTS Four weeks postoperatively,the percentage area of newly formed bone was significantly higher in group III(0.88±0.02)than in groups I(0.02±0.00)and II(0.60±0.02).The amount of granulation tissue formation was lower in group III(0.12±0.02)than in groups I(0.20±0.02)and II(0.40±0.02).The number of inflammatory cells was lower in group III(0.29±0.03)than in groups I(4.82±0.08)and II(3.09±0.07).CONCLUSION Bone regenerative quality of critically sized mandibular bone defects in rats was better promoted by PRF membranes seeded with BMSCs than with PRF membranes alone.

Calcitonin and vitamin D3 have high therapeutic potential for improving diabetic mandibular growth

The goal of this study was to assess the effect of the intermittent combination of an antiresorptive agent （calcitonin） and an anabolic agent （vitamin D3） on treating the detrimental effects of Type 1 diabetes mellitus （DM） on mandibular bone formation and growth. Forty 3-week-old male Wistar rats were divided into four groups： the control group （normal rats）, the control C＋D group （normal rats injected with calcitonin and vitamin D3）, the diabetic C＋D group （diabetic rats injected with calcitonin and vitamin D3） and the diabetic group （uncontrolled diabetic rats）. An experimental DM condition was induced in the male Wistar rats in the diabetic and diabetic C＋ D groups using a single dose of 60 mg.kg-1 body weight of streptozotocin. Calcitonin and vitamin D3 were simultaneously injected in the rats of the control C＋D and diabetic C＋D groups. All rats were killed after 4 weeks, and the right mandibles were evaluated by micro-computed tomography and histomorphometric analysis. Diabetic rats showed a significant deterioration in bone quality and bone formation （diabetic group）. By contrast, with the injection of calcitonin and vitamin D3, both bone parameters and bone formation significantly improved （diabetic C＋ D group） （P 〈 0.05）. These findings suggest that these two hormones might potentially improve various bone properties.

不同垂直骨面型下颌第一磨牙横向位置差异的CBCT研究

目的:使用锥形束CT(cone beam CT,CBCT)测量不同垂直骨面型下颌第一磨牙生理牙槽骨厚度,评估横向磨牙位置。方法:选取2023年1~10月在合肥市口腔医院正畸二科就诊患者50例,分为高角组、均角组及低角组,术前拍摄CBCT,数据导入配套三维软件进行4个部位不同深度牙槽骨厚度的测量分析。结果:高角患者下颌第一磨牙的骨厚度最小。下颌第一磨牙舌侧骨厚度高于颊侧。下颌第一磨牙釉牙骨质界根方4 mm处近中舌侧牙槽骨厚度高于远中舌侧,近中颊侧牙槽骨厚度与远中颊侧比较差异无统计学意义。下颌第一磨牙釉牙骨质界根方8 mm处远中颊侧牙槽骨厚度高于近中颊侧,近中舌侧的牙槽骨厚度与远中舌侧比较差异无统计学意义。下颌第一磨牙同一测量位点釉牙骨质界根方8 mm的牙槽骨厚度高于根方4 mm的牙槽骨厚度。结论:不同的垂直骨面型、测量部位、测量深度、牙齿解剖形态都会反映出下颌第一磨牙在牙槽骨中横向位置的差异。

替牙期骨性Ⅲ类患者下前牙牙槽骨形态测量分析

目的评估替牙期骨性Ⅲ类患者下前牙区牙槽骨形态,并与骨性I类患者进行差异比较。方法选取替牙期骨性Ⅲ类患者48例及骨性I类患者40例,基于治疗前的锥束投影计算机重建层析成像(CBCT),测量下颌中切牙和侧切牙唇舌侧的牙槽骨厚度和高度,对比骨性Ⅲ类及I类患者下前牙区牙槽骨形态差异。结果骨性Ⅲ类组下前牙牙根唇侧和舌侧牙槽骨厚度均显著低于骨性I类组,差异有统计学意义(P<0.05)。骨性Ⅲ类组下前牙舌侧牙槽骨高度与骨性I类无显著差别(P>0.05)。结论替牙期骨性Ⅲ类患者下切牙唇侧及舌侧牙槽骨厚度明显较骨性I类患者薄,在对其进行前牙的唇舌向移动时尤其要注意转矩的控制,评估牙齿安全移动范围,以降低治疗风险,减少并发症。

超声波焊接技术应用PDLLA接骨系统固定兔下颌骨骨折的有限元分析

目的探讨两种不同固定方式对兔下颌骨进行固定后的应力及位移影响。方法健康成年新西兰大白兔,雄性,2~4月龄,体重3.0~3.5 kg,制取兔下颌骨并造骨折模型。基于兔下颌骨标本Micro CT数据,使用软件进行处理后构建兔下颌骨骨折有限元模型。按照固定方式不同分为超声波焊接技术组(超声组)和传统内固定技术组(拧入组),利用模拟弯曲实验以及咬合实验分析两种固定方式下可吸收板、可吸收固定钉以及下颌骨位移及应力情况。结果弯曲实验中,超声组固定性能在位移方面较拧入组好,但在咬合实验中,超声组下颌骨所产生的位移较大,且集中于前牙区,使其稳定性降低,使用超声波焊接技术将颌骨进行固定后,进行咀嚼运动时固定钉易发生松动。结论超声波焊接技术固定性能及初期稳定性与传统内固定技术相似,但还需进行力学实验进一步明确其固定性能,使其更适合应用于口腔颌面部骨折。

口内血管吻合髂骨瓣修复颌骨缺损的临床应用

目的:介绍数字外科引导下利用口内血管吻合技术联合血管化游离髂骨瓣移植在颌骨重建中的临床操作与优势,探讨口内血管吻合技术的临床应用。方法:选取2022年武汉大学口腔医学口腔颌面外科3例因颌骨良性肿瘤需行颌骨切除并同期修复的患者,术前对患者进行颌骨及髂骨CT扫描,制定虚拟手术计划,设计、制作取骨截骨导板,手术切除肿瘤,其中2例为口内入路切除,1例为口外入路切除。截取髂嵴部带血管蒂骨瓣,以面动静脉为受区吻合血管与髂骨瓣血管蒂进行吻合,从而完成髂骨瓣对颌面部缺损的重建修复。随访患者术后恢复情况并进行评估。结果:3例手术均成功完成,其中2例患者无口外切口,1例患者仅有一处原发灶切除为口外切口。术后患者恢复良好,颌面部结构基本对称且美观。结论:口内血管吻合技术与髂骨瓣及虚拟手术计划相结合可以取得良好的术后结果。口内吻合技术不仅可以完成口内颌骨病灶切除后重建,对于需经口外入路切除病灶的病例也有一定优势。

基于Micro-CT评价超声骨焊接技术PDLLA材料对骨愈合性能的影响

目的采用微焦点断层扫描(Micro-CT)评价超声骨焊接技术应用过程中超声震荡产热作用下PDLLA材料对骨愈合性能的影响。方法选择SPF级雄性新西兰大白兔36只,随机分为超声骨焊接技术辅助PDLLA材料组(A组)、拧入技术辅助PDLLA材料组(B组)、假手术组(C组)、空白对照组(D组),各9只。于术后4、8、12周取下颌骨标本,周围骨组织进行HE染色,观察各组植入钉周围情况。对术后4、8、12周的下颌骨大体标本拍摄Micro-CT图,使用VG Studio MAX软件进行三维重建,摆正数据样本,即颌骨颊侧造模处为轴向,动态分析植入钉体积、植入钉周围200μm环状区及骨缺损处的植入材料体积数、相对骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数(Tb.N)、骨小梁间隙(Tb.Sp)等骨愈合相关指标。结果HE染色结果显示,按3个时间可动态观察到A、B、C组骨缺损处骨性骨痂替代纤维性骨痂,形成类骨质,编织骨的过程符合正常骨损伤愈合的过程。Micro-CT结果显示,A、B组术后3个时间点的材料体积比较差异均无统计学意义(P>0.05);在3个时间点,4组植入钉周围200μm环状区中BV/TV、Tb.Th、Tb.N、Tb.Sp比较差异均无统计学意义(P>0.05);在骨缺损处,A、B、C组三个时间点BV/TV、Tb.Th、Tb.N、Tb.Sp比较差异无统计学意义(P>0.05);术后4周,与D组比较,A、B、C组BV/TV、Tb.Th、Tb.N、Tb.Sp差异有统计学意义(P<0.05);与C组比较,A、B组Tb.N差异有统计学意义(P<0.01)。术后8周,与D组比较,A、B、C组BV/TV、Tb.Th、Tb.N、Tb.Sp差异有统计学意义(P<0.05);术后12周,与D组比较,A、B、C组BV/TV、Tb.Th、Tb.Sp差异有统计学意义(P<0.05)。结论超声骨焊接技术其超声震荡产热作用下PDLLA材料对骨愈合性能无不良影响。

骨板翻盖术联合可吸收板固定治疗下颌骨大型囊肿的效果观察

目的观察骨板翻盖术联合可吸收板治疗口腔颌面部大型下颌骨囊肿的临床效果。方法选取2017年10月—2022年9月在中国人民解放军总医院第一医学中心口腔颌面外科诊治的唇(颊)侧皮质骨存在的大型下颌骨囊肿患者为研究对象,口内入路行骨板翻盖术,术后3、6和9个月定期随访进行锥形束计算机断层扫描(CBCT),观察术后患者恢复情况及影像学检查,评估该术式的临床效果。结果对11例唇(颊)侧皮质骨存在的下颌骨大型囊肿进行了评估。术前测量唇(颊)侧皮质骨的平均厚度约为(1.98±0.37)mm,骨板最薄处厚度平均为(0.73±0.17)mm,骨板最薄处约0.51mm。术中囊腔均显露良好,手术顺利完成。术后创口一期愈合无感染,术后3、6、9个月的囊肿缩小率分别约为20.01%、41.76%、73.41%。用CBCT和MIMICS软件测量颌骨的骨质密度,术后3、6、9个月囊肿区成骨密度约为313.78、555.85、657.45 HU。患者和观察者视觉模拟量表评估患者颌面部外形较术前无明显变化。结论骨板翻盖术是治疗唇(颊)侧皮质骨存在的口腔颌面部大型下颌骨囊肿的有效方法。

下颌骨埋伏阻生第三磨牙拔除术后自然转归及对邻近第二磨牙的影响

目的:观察下颌阻生第三磨牙(impacted mandibular third molars,IM3Ms)拔除术后的自然转归及对邻近下颌第二磨牙(mandibular second molars,M2Ms)的影响。方法:选择下颌第三磨牙骨埋伏阻生的患者34例(51颗IM3Ms),使用超声骨刀、气动涡轮手机拔除患牙,分别于术前、术后1周及术后6个月随访,观察术后反应及M2Ms远中骨缺损情况。比较手术前后M2Ms远中骨缺损深度,并分析其影响因素。采用SPSS 29.0软件包对数据进行统计学分析。结果:术前M2Ms远中骨高度未见明显缺损,但拔除IM3Ms时,由于去骨拔牙等操作产生骨缺损。术后6个月,骨高度虽有所恢复,骨缺损率减少,但未达到术前水平。IM3Ms埋伏阻生深度是恢复率的主要影响因素。探诊深度较术前显著增加。术后24 h内患者疼痛感较重,术后1周缓解,但仍存在轻度开口受限及面部肿胀。拔除IM3Ms对患者日常生活、情绪、工作、睡眠影响较小。结论:下颌第三磨牙拔除术后,邻近第二磨牙远中骨高度部分恢复,但未达到术前水平。拔牙手术中需采取更加精细的手术技巧,以减少对邻近牙和骨组织的影响。同时,拔除IM3Ms后应给予镇痛药物,加强卫生宣教,提高患者术后舒适度。

生物可吸收板与微型钛板在不同骨质下颌骨骨折固定中的有限元分析

背景:下颌骨骨折在坚强内固定后的愈合受多种因素影响,包括接骨板的材料、骨折部位以及患者骨密度等,然而,目前对于不同骨质下下颌骨骨折固定稳定性关系的研究相对较少,并且缺乏科学的依据。目的:利用有限元法分析生物可吸收板和微型钛板固定不同骨质条件下颌骨骨折的稳定性。方法:根据ZARB和LEKHOLM提出的骨质分类方法,分别建立Ⅰ-Ⅳ类下颌骨骨折三维有限元模型,每类骨质条件下分别模拟下颌骨正中、体部和下颌角3个部位的骨折模型,采用生物可吸收板(或微型钛板)对上述骨折进行内固定,模拟健侧咬合状态,利用有限元分析骨折段的相对位移与内固定物应力分布情况。结果与结论:①随着骨质等级的增加,内固定物的最大应力值基本呈逐渐增加趋势,微型钛板组、生物可吸收板组下颌体部Ⅳ类骨质下的内固定物最大应力值最高,分别为382.74,96.11 MPa;在相同骨质条件下,钛板组各部位骨折模型的内固定物最大应力值均高于生物可吸收板组。②对于Ⅲ和Ⅳ类下颌骨正中部骨折,微型钛板组、可吸收板固定组骨折断端位移较大,超过了骨愈合极限值(大于150μm);对于Ⅳ类骨质下颌骨体部骨折,生物可吸收板组骨折断端位移超过了愈合极限值,微型钛板组骨折断端位移接近愈合极限值;在相同骨质条件与骨折部位下,微型钛板组骨折断端位移要小于生物可吸收板组。③结果显示,两种内固定物的强度和刚度均足以支持Ⅰ-Ⅳ类骨质下颌骨3种部位骨折的骨愈合,并且生物可吸收板的固定稳定性与微型钛板几乎相同,可以提供骨折早期的愈合条件。在治疗下颌骨骨折时应将下颌骨骨质类型纳入考虑因素,下颌骨骨质等级越高,骨折固定的稳定性越差,术后更易发生骨愈合不良等并发症。

超声骨刀法联合涡轮钻治疗下颌阻生牙对创伤及并发症的影响

目的研究超声骨刀法联合涡轮钻治疗下颌阻生牙对创伤及并发症的影响。方法选取2019年2月至2022年1月在台州市中心医院(台州学院附属医院)就诊的下颌近中低位水平前倾阻生牙患者122例,采用随机数字表法将所有患者分为涡轮钻组与联合治疗组,每组61例。两组患者均进行常规麻醉,口腔锥形束CT检查。涡轮钻组患者在常规基础上行涡轮钻治疗,联合治疗组患者采用超声骨刀法联合涡轮钻治疗。观察拔牙时间、术中出血量、张口受限、肿胀程度、疼痛程度。比较两组患者的创伤发生率及并发症发生率,采用健康调查简表(item short from health survey,SF-36)对生活质量进行评分。结果联合治疗组患者术中出血量及拔牙时间均低于涡轮钻组,差异有统计学意义(P<0.05)。联合治疗组患者张口受限、肿胀及疼痛程度均低于涡轮钻组,差异有统计学意义(P<0.05)。联合治疗组患者术后牙根移位、牙槽骨骨折、软组织损伤及牙根骨折发生率均低于涡轮钻组,差异有统计学意义(P<0.05)。联合治疗组术后干槽症、出血及严重肿胀发生率均低于涡轮钻组,差异有统计学意义(P<0.05)。联合治疗组术后SF-36评分高于涡轮钻组,差异有统计学意义(P<0.05)。结论超声骨刀法联合涡轮钻治疗下颌阻生牙疗效显著,手术创伤小,减少术中出血量、拔牙时间及并发症发生率,提高患者生活质量。

超声骨刀微创拔牙法联合医用胶原蛋白海绵在下颌阻生牙拔除中的应用效果

目的 探究超声骨刀微创拔牙法联合医用胶原蛋白海绵应用于下颌阻生牙拔除的效果。方法 选取2020年12月至2022年12月四川省南充市中心医院收治的150例下颌阻生牙患者为研究对象,采用随机数字表法将其分为两组,各75例。患者均采用超声骨刀微创拔牙法拔除患牙,对照组术中予以常规治疗,试验组术中联合医用胶原蛋白海绵治疗。术后30 min比较两组口腔出血情况;术后24、72 h,评估患者的口腔疼痛程度[视觉模拟评分法(VAS)];术后72 h评估两组开口受限程度;记录术后并发症。结果 试验组术后出血情况优于对照组(P<0.05)。两组不同时间点VAS评分比较,差异有统计学意义(P<0.05);术后24、72 h,试验组VAS评分低于对照组(P<0.05)。试验组术后开口受限严重程度优于对照组(P<0.05)。试验组术后并发症发生率均低于对照组(P<0.05)。结论 超声骨刀微创拔牙法联合医用胶原蛋白海绵应用于下颌阻生牙拔除的治疗中,更有助于降低患者术后的疼痛程度、出血率及并发症发生风险。