利用夹板治疗髁状突纵形骨折突、盘的组织学变化

目的：观察髁状突纵形骨折后及牙合夹板治疗时髁状突、关节盘的改变。探讨牙合夹板治疗机制。方法：实用小型猪１８头,随机分为髁状突纵形骨折后未治疗组,牙合夹板治疗组及对照组各６头。实验后３、６、１２周取材,光镜扫描电镜观察。结果：牙合板治疗髁状突纵形骨折１２周,骨折愈合,无盘突粘连。生发层细胞和表层纤维连续,其下是新生软骨细胞和大量软骨内化骨现象。未治疗组３周关节盘轻度变形,１２周关节盘与髁状突、颞下凹粘连,呈双髁突畸形。电镜下牙合夹板治疗组骨折侧髁突表面凝胶样物质尚存,细胶原纤维暴露。未治疗组骨折侧髁突表面凝胶状物质消失,有的部位胶原纤维粗大,有的部位细小。结论：髁状突纵形骨折未治疗后果为盘突粘连,双髁突畸形。牙合夹板具有防止盘突粘连,使髁状突恢复正常生长发育的作用。     

颏部骨折伴髁突外上方脱位的治疗体会(附10例报告)

颏部骨折合并髁突骨折伴前内侧移位临床上常见,但颏部骨折伴髁突外上方脱位非常少见,容易漏诊和误诊,治疗不当易导致关节强直等后遗症.该文回顾10例颏部骨折伴髁突外上方脱位,并结合文献讨论其发生机制,诊断特征和临床治疗.     

髁突形态与髁突矢状骨折发生率之间的关系分析

目的：分析髁突形态与单侧髁突矢状骨折(sagittal fracture of mandibular condyle, SFMC)发生率之间的关系。方法：回顾2010年12月—2021年12月河北医科大学第三医院收治的155例单侧髁突矢状骨折患者的病例资料,将其螺旋CT数据以DICOM格式导入RadiAnt DICOM Viewer软件。根据Yale的髁突形态的分类标准,将髁突形态分为平、凸、角、圆4种。根据Hlawitschka的髁突矢状骨折分类标准,将髁突矢状骨折分为A、B、M 3类,分析髁突形态与单侧髁突矢状骨折发生率之间的关系。采用SPSS 26.0软件包对数据进行统计学分析。结果：155例患者中,健侧髁突形态占比分别是平形41.9%、凸形37.4%、圆形11.6%、角形9.0%,髁突矢状骨折的分类占比分别是A型20.6%、B型42.6%、M型36.8%。不同髁突形态的髁突矢状骨折发生率不同,两者之间存在相关性(P=0.015)。平形髁突相比其他3种类型的髁突更容易发生矢状骨折,角形髁突最不容易发生矢状骨折。结论：髁突形态不同会影响髁突矢状骨折发生率,平形髁突更容易发生髁突矢状...     

单侧下颌第三磨牙伸长患者接触特征的研究

目的:探讨单侧下颌第三磨牙伸长患者的接触特征以及拔除伸长牙后对患者咬合关系的改善程度。方法:应用T-ScanⅢ咬合分析仪记存22例单侧下颌第三磨牙伸长患者牙尖交错位、前伸及侧方运动的咬合记录,并与正常组以及患者拔牙后的咬合记录的结果作对照。结果:单侧下颌第三磨牙伸长组的力中心距中线距离与正常对照组以及拔牙组相比较,其差异均有统计学意义;单侧下颌第三磨牙伸长组的闭合时间、分离时间与正常对照组相比较,差异均有统计学意义。而拔牙组与正常对照组相比较,仅闭合时间、前伸分离时间差异有统计学意义;早接触、干扰出现率与单侧下颌第三磨牙伸长存在关联性。结论:单侧下颌第三磨牙伸长患者咬合稳定性和平衡性较差,拔除伸长的下颌第三磨牙可使咬合稳定性有一定程度的改善。     

Clinical and radiological outcomes after treatment of sagittal fracture of mandibular condyle (SFMC) by using occlusal splint in children

This study was designed to investigate the effects of occlusal splints in the treatment of sagittal fractures of the mandibular condyle in children. From January 1995 to December 2011, 37 sagittal fractures of the mandibular condyle in 30 patients aged 4–8 years old were included in this study. All the patients were treated with 1–2 mm occlusal splints in the molar region. The mouths of the patients were kept slightly open by the occlusal splints for 3–6 months, and we reviewed the clinical and radiological remodelling of the affected condyles after treatment. Excellent (n = 20) and good (n = 10) clinical outcomes were achieved with full radiological remodelling seen in 19 and partial remodelling in 11. Treatment with occlusal splints is effective in delivering good results and function with minimal morbidity in children with sagittal fractures of the condyle, while permitting ongoing remodelling and growth in the short term.     

Investigating the correlation between bone density and fracture frequency in the mandibular condyle with micro-computed tomography

Fractures of the mandibular condyle are common and include diacapitular fractures that affect the condylar head. The medial part of the condylar head is least commonly fractured, possibly due to decreased propensity for lines of force to run in the region. Micro-computed tomography (X-ray microtomography) of five temporomandibular joint specimens was conducted to explore whether trabecular bone structure correlates positively with fracture prevalence, which could reflect adaptation in response to lower exposure to physiological loads throughout life. Models of trabecular bone, and graphic representation of bone density indicated least dense bone medially, but a statistically significant ANOVA result was not obtained. Further study is required to verify whether a relationship between bone microstructure and fracture frequency exists, and whether or not this is the product of association between the directions of physiological and traumatic forces.     

28例颏部骨折合并髁突囊内骨折伴脱位的疗效分析

目的 探讨下颌骨颏部骨折合并髁突囊内骨折伴脱位的治疗方法,并比较髁突骨折不同处理方法对治疗效果的影响。方法 2008—2013年间收治28例、44侧颏部骨折合并髁突囊内骨折患者,22侧髁突囊内骨折采用手术治疗,手术中注意保护翼外肌的附着;其余22侧采取保守治疗,术前或术中取模,术后配戴颌垫并配合弹性牵引及开口训练。应用SPSS17.0软件包对治疗结果进行Wilcoxon秩和检验。结果 手术治疗组髁突骨折22侧,术后髁突位置基本回复到关节窝内17侧,其牙弓宽度及咬合关系基本恢复,术后髁突仍然脱出关节窝5侧;保守治疗组22侧,术后髁突成功回复到关节窝内4侧,其余18侧脱出关节窝,其面下1/3仍有不同程度增宽。手术治疗组疗效评分显著优于保守治疗组（P<0.01）。结论 对颏部骨折合并髁突囊内骨折伴脱位患者,应在保持翼外肌良好附着的前提下,对脱位的髁突骨折进行复位和固定,这样有利于脱位的髁突恢复到正常的生理位置,维持下颌骨的正常宽度。     

Evaluation of recovery in lip closing pressure and occlusal force and contact area after orthognathic surgery

PurposeThe purpose of this study was to evaluate the relationship between lip closing force, occlusal contact area and occlusal force after orthognathic surgery in skeletal Class III patients.Subjects and methodsThe subjects consisted of 54 patients (28 female and 26 male) diagnosed with mandibular prognathism who underwent sagittal split ramus osteotomy with and without Le Fort I osteotomy. Maximum and minimum lip closing forces, occlusal contact area and occlusal force were measured pre-operatively, 6 months and 1 year post-operative.ResultsMaximum and minimum lip closing forces, occlusal contact area and occlusal force increased with time after surgery, however a significant increase was not found in the occlusal contact area in women. In increased ratio (6 months/pre-operative and 1 year/pre-operative), the maximum lip closing force was significantly correlated with the occlusal contact area (P < 0.0001).ConclusionsThis study suggested that orthognathic surgery could improve the occlusal force, contact area and lip closing force, and an increase ratio in maximum lip closing force was associated with an increased ratio in occlusal contact area.     

Occlusal contacting condition and masticatory function of 2 types of pattern that differ in the closing path of the mandibular incisal point during chewing

Purpose

To clarify the difference in the state of occlusal contact and masticatory function between two patterns of masticatory movement path that differed in the closing path.

Methods

Fifteen healthy subjects with Pattern I (a linear or concave opening path and a convex closing path) and Pattern II (similar opening path to that in Pattern I and a concave closing path) were selected. The state of occlusal contact on the working and balancing sides and the masticatory function (integral value of the masseter muscular activity, gape, masticatory width, cycle time, indicators representing the stability of the path and rhythm, and glucose extraction) were compared between the two patterns.

Results

The occlusal contact on the working side was about the same. For the balancing side, occlusal contact at the molar region was observed for Pattern II in most cases, whereas no occlusal contact was observed for Pattern I. The integral value of the masseter muscular activity and the glucose extraction were greater for Pattern I. The gape was not different between the two patterns. Pattern I had a wide masticatory width and a short cycle time. The values of the indicators representing the stability of the path and rhythm were smaller for Pattern I.

Conclusion

It was suggested that Pattern I with a convex closing path had a functional difference and a superior masticatory function from Pattern II with a concave closing path, and the difference in the occlusal contact on the balancing side was related.     

Microbiological investigation of the mandibular condyle in patients with advanced osteoarthritis of the temporomandibular joint

PurposeThe aim of this study was to investigate the presence of bacteria in samples of the temporomandibular joint taken from patients suffering from advanced osteoarthritis of the temporomandibular joint (TMJ).Materials and methods25 fresh mandibular condyle samples were taken from 17 consecutive patients undergoing mandibular condylectomy (8 bilateral) for advanced TMJ osteoarthritis (Dimitroulis Category 5 joints). The joint samples were stained and cultured for the presence of microorganisms following a standardised joint culture protocol.ResultsNo evidence of bacteria was found on staining or solid culture mediums. Late growth (day 12) of commensal skin organisms (P. Acnes, S. Epidermitis, S. Capitis) were identified in enriched broth samples in 5 joint samples. No statistically significant associations were noted between positive broth samples and age or previous joint intervention (p > 0.05)ConclusionsWithin the limitations of this study, we have failed to identify meaningful bacterial growth in tissues (i.e. condylar head) of the TMJ that would suggest a contributory bacterial pathogenesis for arthritis of the TMJ.     

A clinical investigation on disc displacement in sagittal fracture of the mandibular condyle and its association with TMJ ankylosis development

This retrospective study evaluated the potential influence of the sagittal fracture pattern and articular disc displacement on the development of temporomandibular joint (TMJ) ankylosis. 33 sagittal fractures of mandibular condyles (SFMCs) in 19 patients were treated conservatively and were divided into non-ankylosis and ankylosis groups based on their prognosis. Using computed tomography (CT) images, the SFMCs were classified into types I, II and III, and the displacement of the articular disc was investigated using magnetic resonance imaging (MRI). There were 19 (58%) SFMCs in the non-ankylosis group: 5 were type I SFMCs, which did not show any disc displacement; the other 14 were type II SFMCs, which included 5 cases without disc displacement and 9 cases with disc displacement. In the non-ankylosis group, the lateral poles were completely or incompletely covered by the discs. There were 14 (42%) SFMCs in the ankylosis group, all of which were type III SFMCs showing disc displacement, and the lateral poles in these cases were not covered by the discs. This investigation confirmed that the disc position was highly associated with the position of the fractured fragment and that some SFMC patterns, especially type III SFMCs, indicated a high risk of TMJ ankylosis.     

Assessment of masticatory function in patients with non‐sagittal occlusal discrepancies

Non‐sagittal occlusal discrepancies such as posterior cross‐bite and anterior openbite are common types of malocclusion, but studies on masticatory function related to those malocclusions have been scarce. The aim of this study was to quantify the masticatory performance in patients with non‐sagittal discrepancies compared to those with normal occlusion, using both objective and subjective measures. Maximum bite force and contact area using Dental Prescale^® system as a static objective assessment, Mixing Ability Index (MAI) as a dynamic objective evaluation and food intake ability (FIA) as a subjective assessment were analysed from 21 people in normal occlusion (Group N) and 64 patients with posterior cross‐bite (Group C), anterior openbite (Group O) or both (Group B). The differences of the maximum bite force, the contact area, the MAI and the FIA were compared, and their correlations were figured out. The non‐sagittal malocclusion groups showed lower values in the maximum bite force, the contact area, the MAI and the FIA compared to those in the normal group (P < 0·0001). Compared to Group N, Groups C, O and B showed 61·5%, 42·1% and 40·1% of the maximum bite force, and 84%, 84% and 76% of hard food FIA, respectively. However, there were no significant differences among Groups C, O and B. The MAI showed higher correlation with the FIA (r = 0·38, P < 0·01), than with the maximum bite force and the contact area (both r = 0·24, P < 0·5). These results revealed that masticatory function in patients with non‐sagittal discrepancies is significantly reduced both objectively and subjectively.     

Relationships between the root-crown ratio and the loss of occlusal contact and high mandibular plane angle in patients with open bite

Objective:To determine the root-crown (R/C) ratio and dental root length of teeth in patients with open bite and seek any relationships with occlusal contact (OC) and the mandibular plane (Mp) angle.Materials and Methods:Thirty-one patients with open bite with negative overbite of at least four anterior teeth and 31 control patients with clinically normal overjet and overbite were enrolled. R/C ratios, dental root length, OC, and Mp angle were measured using panoramic radiographs, dental casts, and cephalograms, respectively. Mean differences between the groups, and variations between the R/C ratio or root length and Mp angle in patients with open bite were statistically analyzed.Results:R/C and OC ratios from the incisors to premolars were significantly lower for patients with open bite than for controls, and some teeth had short dental roots. Relationships between low R/C ratio or root length and high Mp angle were significant in patients with open bite.Conclusion:Patients with open bite, especially those with a high Mp angle, have an unfavorable R/C ratio and short dental roots in some teeth, which may be related to the loss of OC.     

钛板坚强内固定治疗下颌骨骨折136例报告

目的：总结钛板坚强内固定术治疗下颌骨骨折的临床疗效。方法：收集1998～2004年136例下颌骨骨折病例,行钛板坚强内固定术治疗,分别在手术后1个月、3个月、6个月复查,拍摄X线片,观察骨折线对位愈合情况、咬合关系及开口度等功能恢复情况。结果：136例中134例一期愈合,2例延期愈合。X线片示骨折线对位良好,咬合关系及开口度均恢复良好。结论：钛板坚强内固定术治疗下颌骨骨折效果好,方法可靠,操作简单。     

A structural equation model to investigate the impact of missing occlusal units on objective masticatory function in patients with shortened dental arches

The aim of this study was to investigate the impact of missing occlusal units (MOUs) on objective masticatory function with respect to food comminuting and mixing ability. Sixty partially dentate patients (mean age, 64·1 years) with shortened dental arches participated in the study. Food comminuting ability was assessed using a masticatory performance test with peanuts as a test food. Food mixing ability was assessed using a mixing ability test with a two-coloured wax cube. Maximum bite force (MBF) was measured using a pressure-sensitive film as a mediator for food comminuting and mixing ability. A structural equation model was constructed based on a hypothesis that MOUs would be associated with reduced MBF and impairment of food comminuting and mixing ability. Structural equation modelling analysis found significant direct effects of MOU on median particle size and mixing ability index (MAI) (P < 0·001). In addition, MOU had significant indirect effects on median particle size and MAI with MBF as a mediator (P < 0·05). These results suggest that decrease in occlusal platform area and reduced MBF because of MOUs are associated with the impairment of food comminution and mixing in patients with shortened dental arches.     

Changes of disc status in adult patients with condylar head fracture who did or did not undergo disc anchoring operation

Purpose

Views on treatment procedures for condylar head fractures (CHFs) are far from reaching a consensus. The aim of this study was to evaluate the changes in disc status for anteromedial disc displacement with anchorage (AMDDwA) and without anchorage (AMDDwoA — just suturing to the adjacent TMJ soft tissue) in adult CHFs, to get a better understanding of this very complex process and to show that rigid disc anchorage is an essential technique for the treatment of CHF during the open reduction and internal fixation (ORIF).

Relationship between arthroscopic findings of synovitis and levels of tumour necrosis factor‐alpha and matrix metalloproteinases in synovial lavage fluid from patients with unilateral high mandibular condyle fractures

Arthrocentesis has an effect of washing out inflammatory products that accumulate in the joint compartment of a dysfunctional temporomandibular joint (TMJ). The procedure removes inflammatory cytokines, which are pain‐causing substances, for early reduction of TMJ pain and quick recovery of jaw function, thus increasing the possibility of a successful rehabilitation. The aim of this study was to investigate the relationship between arthroscopy synovitis grade in patients with unilateral high condylar fractures and concentrations of the pro‐inflammatory cytokines tumour necrosis factor (TNF)‐alpha as well as of matrix metalloproteinases (MMPs) in washed‐out synovial fluid (SF) samples obtained from those patients. A total of 26 patients with unilateral high condylar fractures who underwent arthrocentesis for a therapeutic purpose were examined. SF samples were collected before performing arthroscopy to determine synovitis grade. The detection rates and concentrations of TNF‐alpha and MMPs were determined, and their association with synovitis grade was analysed. TNF‐alpha was detected in 23 and MMP‐3 in 22 of the TMJs. There was a correlation between synovitis grade and concentration of TNF‐alpha in the fracture group. Furthermore, the concentrations of TNF‐alpha and MMP‐3 were significantly higher as compared to the control group, comprised of TMJs on the non‐fracture side of the same patients, while a correlation was also noted between TNF‐alpha concentration and synovitis grade in the fracture group. The present findings may provide a biological/biochemical rationale for arthrocentesis as a reasonable treatment modality for high condylar fractures.     

Changes in the position of the condyle after bilateral sagittal split ramus osteotomy in patients with mandibular retrusion and protrusion: a new condyle: fossa matching concept

The purpose of this study was to compare the condylar positional changes after bilateral sagittal split ramus osteotomy (BSSRO) in patients with mandibular retrusion and those with mandibular prognathism. We also studied the correlation between the degree of matching of the condyle and fossa, and condylar displacement. Thirty patients with mandibular retrusion (n = 11) or mandibular prognathism (n = 19) who underwent BSSRO were included. The condylar position was assessed from spiral computed tomographic (CT) scans taken preoperatively, during the first postoperative week, and at least 6 months postoperatively. All data were measured by MIMICS 17.0 and analyzed by Student’s t test and Pearson’s correlation analysis. The size of the condyles of patients with mandibular retrusion was significantly less than those of patients with mandibular prognathism (491.5 (172.8) compared with 823.2 (212.0) mm³). The size of the glenoid fossa in those with mandibular retrusion (599.6 (110.4) mm³) and those with prognathism (597.6 (151.6) mm³) did not seem to differ. Postoperatively the condyles moved outwards, backwards, and downwards in both groups of patients. Correlation analysis between the condyle:fossa volume ratio and the condylar positional changes showed that a large condyle:fossa volume ratio correlated with the smaller positional changes in the condyle. The condylar position changed immediately after mandibular advancement and setback, and persisted in the long term. Larger condyles tended to have fewer positional changes.     

Occlusal pressure, contact area, force and the correlation with the morphology of the jaw-closing muscles in patients with skeletal mandibular asymmetry

Summary  The purpose of this study was to investigate the difference in the occlusal force between deviated and non-deviated sides of the mandible in adult patients with skeletal mandibular asymmetry, and then also compare the findings to those obtained from controls. The absolute and balance data of the occlusal pressure, occlusal contact area and occlusal force of 23 patients and the controls were examined. Correlations between the occlusal force and the morphology of the jaw-closing muscles were also analysed. The occlusal pressure of patients was not smaller than controls, however, the occlusal contact area and occlusal force in patients were significantly lower than those in the controls. There was no significant difference in the balance of the occlusal contact area and the occlusal force between the right and left sides in the controls, while the balance was shifted to the deviated side in the patients. Interestingly, the balance of the occlusal pressure was very similar between the patients and the controls. Most parameters of the morphology of the jaw-closing muscles did not show a linear correlation with either the occlusal pressure or force. In conclusion, the occlusal contact area and occlusal force in patients were significantly lower than those in the controls, and also the balance was shifted to the deviated side in patients with skeletal mandibular asymmetry. It is assumed that the morphology and orientation of jaw-closing muscles may have not linear but complex correlation to the weaker and unbalanced occlusal force in patients.