下颌角不利型骨折小型钛板内固定有限元分析

目的:用三维有限元方法评价下颌角不利型骨折小型钛板坚固内固定稳定性,为下颌角骨折坚固内固定提供生物力学的理论支持.方法:建立下颌角不利型骨折的三维有限元模型,按照下颌角小型钛板外斜线单块钛板固定及下方增加一块钛板固定,分别模拟切牙咬合及健、患侧磨牙咬合,得出骨折段的相对位移情况.结果:下颌角不利型骨折,切牙功能咬合时,骨断端位移在150μm内,但在健侧及患侧磨牙功能咬合情况下,骨断端位移较大.2块小钛板固定时,骨断端相对位移量较大,需要降低咬合力至80 N,1块钛板固定,骨断端相对位移量大,不能保证骨折顺利愈合.结论:下颌角不利型骨折2块小钛板固定稳定性不足,需要降低咬合力;1块小钛板张力带固定不够稳定,需要严格选择适应证.     

下颌角骨折治疗后并发症的临床分析

目的研究下颌角骨折治疗后并发症,分析原因并提出预防方法。方法回顾分析我院206例下颌角骨折患者的治疗及并发症情况,分颌间固定组62例,内固定组120例,颅颌绷带组24例。结果治疗后发生的并发症有骨感染4例,医源性损伤2例,牙合干扰3例,错牙合畸形2例,颞下颌关节功能紊乱病2例。结论下颌角骨折的治疗应首选坚强内固定,应选择正确的手术方案,加强术前、术后抗感染治疗及术后肌功能训练,对骨折线上的阻生齿应尽可能保留,以减少并发症。     

Treatment methods for fractures of the mandibular angle.

Fractures of the mandibular angle are plagued with the highest rate of complication of all mandibular fractures. Over the past 10 years, various forms of treatment for these fractures were performed on an indigent inner city population. Treatment included: 1) closed reduction or intraoral open reduction and non-rigid fixation; 2) extraoral open reduction and internal fixation with an AO/ASIF reconstruction bone plate; 3) intraoral open reduction and internal fixation using a solitary lag screw; 4) intraoral open reduction and internal fixation using two 2.0 mm mini-dynamic compression plates; 5) intraoral open reduction and internal fixation using two 2.4 mm mandibular dynamic compression plates; 6) intraoral open reduction and internal fixation using two non-compression miniplates; 7) intraoral open reduction and internal fixation using a single non-compression miniplate; and 8) intraoral open reduction and internal fixation using a single malleable non-compression miniplate. This paper reviews the results of those modes of treatment when used for the same patient population at one hospital. Results of treatment show that, in this patient population, the use of either an extraoral open reduction and internal fixation with the AO/ASIF reconstruction plate or intraoral open reduction and internal fixation, using a single miniplate, are associated with the fewest complications.     

Treatment of condyle fracture caused by mandibular angle ostectomy

A prominent mandibular angle is considered to be unattractive in Asian countries because it gives the face a square and muscular appearance. Successful correction by angle ostectomy has been reported, but one of the serious complications of angle reduction ostectomy is fracture of the mandibular condyle. If the ostectomy line is misdirected vertically, the condyle may be fractured. The authors experienced two cases of condylar fracture during angle reduction. Case 1 was a pulled-out condylar fracture, where an L-shaped miniplate was then attached by external approach, and intermaxillary fixation (IMF) with arch bar was used on postoperative day 14. With release of the IMF, a systematic approach for a jaw-opening exercise was begun. On postoperative day 21, the elastics were placed to assist in guiding protrusion of the mandible anteriorly 24 hours a day. After postoperative day 28, it was possible to completely abandon daytime elastic fixation. The exercise was modified to lateral movement. Case 2 was green-stick condylar fracture, with the IMF with arch bar applied on postoperative day 10. After releasing the IMF, the exercise involved the daily use of several tongue blades, and range of motion increased by wedging additional blades until postoperative day 21. More aggressive stretching was continued with 22 blades on postoperative day 28. On the removal of the arch bar, the occlusion was stable and followed by more aggressive stretching and physical therapy. Both cases were successfully restored and had good results. The authors believe the exercise protocols and algorithms they used may serve as a standard procedure of treatment in condylar fracture caused by angle ostectomy.     

Do mandibular third molars alter the risk of angle fracture?

PURPOSE: In this study, we measured the relationship between the presence of mandibular third molars (M3s) and angle fractures. In addition, the study examined the relationship between M3 impaction level and angle fracture susceptibility. PATIENTS AND METHODS: We used a multicenter retrospective cohort study design and a sample composed of patients treated for mandibular fractures. The predictor variables were 1) the presence of an M3 and 2) the position of an M3 classified according to the Pell and Gregory system. The outcome variable was the presence or absence of an angle fracture. RESULTS: The study sample was composed of 1,210 patients. Patients with M3s present had a 2.1 times greater chance of an angle fracture than did patients without M3s (P <.001). There was a statistically significant variation in the risk for an angle fracture depending on M3 position (P <.001). CONCLUSIONS: In patients who sustain a mandible fracture, the presence of M3s significantly increases the likelihood of an angle fracture. In addition, the risk for an angle fracture depends on M3 position.     

A biomechanical evaluation of mandibular angle fracture plating techniques.

PURPOSE: The purpose of this investigation was evaluate the biomechanical behavior of a vast array of fixation philosophies and techniques that address mandibular angle fractures. MATERIALS AND METHODS: A total of 150 polyurethane synthetic mandible replicas (Synbone, Laudquart, Switzerland,) were used in this investigation. Five controls and 5 each of 14 different fixation philosophies and techniques were subjected to vertical loading at the incisal edge and then repeated for contralateral loading in the molar region by an Instron 1331 (Instron, Canton, MA) servohydraulic mechanical testing unit. The fixation philosophies and techniques evaluated were the lag screw technique, monocortical superior border plating techniques with varying sizes of plates and screws, monocortical 2-plate techniques with varying forms of fixation, monocortical tension band systems with associated bicortical stabilization plates of various types, and various forms of reconstruction plates. Load/displacement data within a 0 to 200 N range were recorded. Yield load, yield displacement, and stiffness were determined. Mean and standard deviations were calculated, and statistically significant differences within and among categories were determined using an analysis of variance (P <.05). Second-order polynomial best-fit curves were also created for each group to further evaluate and compare the mechanical behavior. RESULTS: For incisal edge loading, statistically significant differences (P <.05) were found for stiffness between some of the monocortical superior border fixation techniques, as well as for yield displacement between several forms of monocortical 2-plate fixation techniques. No other differences were found within categories or among the groups that best represented their categories. For contralateral molar loading, statistically significant differences existed within and among categories. CONCLUSIONS: Under the conditions of this experiment, all systems met or exceeded currently identified postoperative functional requirements for incisal edge loading, but failed to meet them for contralateral molar loading.     

Management of mandibular angle fractures using the mandibular angle reduction forceps

The aim of this study was to determine whether or not the use of the mandibular angle reduction forceps decreases the incidence of post-operative complications. Forty-six patients, who presented with mandibular angle fractures with a displacement or dislocation, were randomly divided into two treatment groups. Both groups underwent an open reduction with a single upper border miniplate and screw fixation. For 23 patients, the mandibular angle reduction forceps was used to aid in fracture reduction, and for 23 patients, the reduction of the fracture was achieved using IMF. The post-reduction radiographs showed that the reduction forceps group had a higher proportion of precise anatomic alignment of fracture than those in the IMF group. In addition, the former group showed a lower rate of post-operative complications, as compared to the latter group. This study found that the use of the mandibular angle reduction forceps is an important factor for decreasing the incidence of post-surgical complication.     

Effects of different mandibular fracture patterns on the stability of miniplate screw fixation in angle mandibular fractures

The aim of the present study was to evaluate the effects of horizontally favourable and unfavourable mandibular fracture patterns on the fixation stability of titanium plates and screws by simulating chewing forces. Favourable and unfavourable mandibular fractures on 22 sheep hemimandibles were fixed with 4-hole straight titanium plates and 2.0mm×7mm titanium screws according to the Champy technique. Hemimandibles were mounted with a fixation device in a servohydraulic testing unit for compressive testing. Displacement values under 20, 60, 100, 120, 150, 200N, maximum displacements, and maximum forces the model could resist before breakage were recorded and compared. The authors found no statistically significant differences between the groups for the displacement values in the force range 60-200N (60, 100, 120, 150 and 200N). Statistically significant differences for maximum displacement values (displacement values at the breaking forces) between the groups were found (P<0.05). There was no evidence for the need to apply different treatment modalities to mandibular fractures regardless of whether the factures are favourable or not.     

Biomechanical evaluation of magnesium plates for management of mandibular angle fracture

The aim of this study was to evaluate the efficacy of magnesium plates for the management of fractures of the mandibular angle. Fresh sheep hemimandibles were divided into 7 groups and a biomechanical cantilever bending test was used for the groups: Group 1 included fractured hemimandibles fixed at the angle with a single 1mm magnesium miniplate; Group 2 had fixation with a 1mm double magnesium miniplate; Group 3 used a 2mm thick single magnesium miniplate; Group 4 used double 2mm magnesium plates; Group 5 each had a single 1mm thick titanium plate; Group 6 used 1mm thick double titanium plates; and Group 7 comprised intact hemimandibles. Each group was tested using universal testing machine yield loads; yield displacements and stiffness were compared using one way analysis of variance (ANOVA) Group 1 (1mm single magnesium plate) and Group 2 (1mm double magnesium plates) showed lower stability than other groups, while the 2mm magnesium plate showed stability similar to the corresponding 1mm titanium plate. Pure magnesium has good mechanical properties and when it is designed properly it can be used for the management of mandibular fracture.     

Postoperative infection associated with mandibular angle fracture treatment in the presence of teeth on the fracture line: a systematic review and meta-analysis

The aim of this review was to answer the question: Which is the best procedure to follow when there is tooth involvement in the line of mandibular angle fracture, taking into consideration the occurrence of postoperative infection? A systematic literature review using the PubMed (MEDLINE), Virtual Health Library (VHL), Cochrane Library, and Scopus databases was done, and a total of 1007 articles were found. Among these, 13 articles were included in the final review after the papers were read. A series of 1542 mandibular angle fractures with the presence of teeth in the fracture line was obtained. Of 788 cases where the tooth was removed, a postoperative infection occurred in 84 cases; of 754 cases where the tooth was retained, postoperative infection also occurred in 84 cases. Through this review it was observed that there was no significant statistical difference between removing or retaining the tooth in the line of fracture and the occurrence of postoperative infection.     

Predictors of treatment preference for mandibular fracture

Background: Patient treatment preferences do not necessarily remain stable over time.
Objective: This study focuses on predictors of patient treatment choice and on the extent to which patients are willing to take risks by choosing surgical versus non-surgical treatment for mandibular fracture.
Methods: Surveys of African-American and Hispanic adults receiving treatment at King/Drew Medical Center for either a mandibular fracture ( n  = 98) or third-molar removal ( n  = 105) were used to investigate patterns of patient preference over the course of a 4-month study period using generalized estimating equations controlling for age, gender, income, and fracture versus third-molar patient. The study examined the effects of symptom rating and a standard gamble measure reflecting a patient's willingness to accept scarring or nerve damage. This analysis is based on 169 patients who participated in four waves of data collection.
Results: The most salient predictor of patient treatment was the standard gamble measure at 1-month follow-up. Subjects with higher risk tolerance were more likely to select surgery versus jaw wiring. A higher likelihood of choosing surgery was associated with higher income and greater symptom severity. Fracture patients were more likely to select surgery compared with third-molar patients.
Conclusions: The significance of symptom severity 1-month post-surgery raises an important issue regarding the healing process. Moreover, the significance of standard gamble as a predictor of treatment choice for mandibular fracture should encourage other researchers to use this measure of willingness to accept risk when studying acute conditions such as jaw fracture.     

Long-term results of the treatment of mandibular condyle fracture

Long-term result of conservative and surgical treatment of varying types of mandibular condyle fracture in 34 cases was investigated. The study shows that 90% cases of condyle fracture, including that complicated with dislocation and displacement, could be successfully treated with simple immobilization by intermaxillary elastic bands. The long-term result of close reduction is closely related to the interval between the trauma and the start of treatment, the earlier the beginning of the treatment, the better the result. The unfavourable immediate result in form of imperfect occlusion and excursion, etc. could be corrected by forced mandibular movement. 10 cases complicated with badly dislocation or communicated fracture were treated with condylectomy, satisfactory results were achieved in 80% of them.     

The mandibular plane angle in activator treatment.

The long-term results of activator treatment were investigated in 15 subjects with a small and 13 subject with a large pretreatment mandibular plane angle. The results of the investigation revealed the following: 1. Activator treatment resulted in a general improvement in the sagittal and vertical incisor relationship in both large and small angle cases. 2. Overjet relapse was more frequent and overbite relapse less frequent in large angle cases than in small angle cases. 3. During the period before treatment follow-up examination the frequency of patients with open bite increased in the large angle group and decreased in the small angle group. 4. The mandibular intercanine arch width was smaller and the frequency of crowding in the mandibular incisor segment was higher in the large angle group than in the small angle group. 5. A large pretreatment mandibular plane angle, per se, was not a primary factor in treatment failure. However, an unfavourable mandibular growth in combination with an atypical tongue function seemed to be the main reason for the relapse found in the large angle subjects.     

下颌骨骨折诊治的临床探讨

目的：寻求一种可靠的下颌骨骨折诊断手段及符合生理的有效治疗方法。方法：在不同时期,分别对203例患者选用5种不同方法的治疗,并结合临床给予正确评价。结果：203例下颌骨骨折中,优良率为92．6％;差率为7．4％。结论：通过五种治疗方法的临床探讨及疗效评价,微型钢板内固定治疗下颌骨骨折是一种较理想的方法,符合动静结合的生理要求。     

髁突矢状骨折的特征和治疗

目的探讨髁突矢状骨折(SFMC)的临床特征和治疗。方法对21例SFMC患者(23侧)的外伤情况、治疗方式、影像学资料进行了研究,并进行了随访。结果SFMC的主要的症状和体征是颞下颌关节区的疼痛(21/21)、张口受限(18/21)、前牙开(13/21)、咬合偏斜(12/21)。SFMC在2D-CT和3D-CT上具有明显的特征,对SFMC的诊断有重要的意义。所有患者治疗后下颌均能进行良好的前伸运动、侧向运动及开颌运动。结论SFMC应根据骨折片的移位情况和患者的年龄选择治疗方式,通过有效的治疗,髁突可以获得良好的功能。