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An efficient band of tension is critical for the adequate fixation of mandibular fractures, so fixation devices that compress are helpful. We aimed to evaluate the possibility of creating compression using screws inserted divergently into miniplates placed in the tension zone of mandibular fractures and record the effects on the strength of fixation. For this in vitro experimental study we prepared 20 sheep hemimandibles. After angle fractures had been created, the specimens were divided into standard and study groups (n=10 in each). In the standard group the tension zones were fixed in the standard manner with 4-hole miniplates and 4 parallel screws. Those in the study group were fixed as for the standard group but with 4×45° divergent screws. The differences in the gap in the fracture line before and after fixation were measured as indicators of compression. The strength of fixation was also assessed with a universal testing machine in vitro. The amount of compression was significant only in the study group (p<0.001), and there was no difference in the strength of fixation between the two groups (p=0.7). We conclude that divergent drilling and insertion of screws creates more horizontal force when miniplates are used, and results in reduction in the size of the probable gap in the fracture line. Insertion of divergent screws in miniplates may create compression between fractured segments without jeopardising the strength of fixation., (Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

We tested the tissue reactions and mechanical strength of a novel biodegradable craniomaxillofacial plating system, Inion CPS, in the course of degradation. Plates and screws composed of L-lactide, D-lactide and trimethylene carbonate were implanted to the mandible and dorsal subcutis of 12 sheep. The animals were sacrificed at 6-156 weeks. Histological evaluation was done using paraffin and methylmetacrylate techniques. Degradative and mechanical properties during the follow-up were measured both of in vivo and in vitro implants. In light microscopy, the in vivo implant material began to fragment at 52 weeks and could not be detected at 104 weeks. No significant foreign body reactions were seen in the mandibles. The dorsal subcutis disclosed mild reactions, which were, however, not of clinical significance. The implants in vitro maintained their entire mass for 26 weeks and lost 63-80% of the mass by week 104. The inherent viscosity of the implants in vitro and in vivo diminished uniformly. The screws retained their shear strength for 12-16 weeks. The plates maintained their tensile strength for at least 6 weeks. The maximum capacity of the plates in 3-point bending tests diminished gradually by 87% in 26 weeks. In conclusion, the plates and screws examined maintain adequate strength for the healing period of a bone fracture or osteotomy, producing no harmful foreign body reactions.

The fixation of diacapitular fractures of the mandibular condyle utilising a headless cannulated bone screw (Martin HBS((R))) is described. An open approach was used with primary fixation of the fracture with a K-wire, over which the cannulated screw was inserted. The method and results are described.

Background: Fractures of the mandible are among frequently seen facial injuries and their reconstruction requires unique procedures. The purpose of this study is to demonstrate the efficacy of screw-wire combination osteosynthesis technique in the treatment of simple and displaced, symphisis and parasymphisis mandible fractures., Methods: In our clinic 9 simple and displaced, symphysis and parasymphysis fractures of mandible were treated with screw-wire combination osteosynthesis technique. By intraoral approach 4 screws were applied to both sides of the fracture site 5 mm away from either side placed at superior (n = 2) and inferior (n = 2) localizations. Lower and upper wires were placed bicortically, and unicortically respectively . In order to surround them with wire, the screws were not fully tightened. After surrounding the screws, the wires were tightened in a manner that would properly face the fracture sites mutually. Intermaxillary fixation was applied for 7 to 10 days in all patients., Results: During follow up period we did not encounter infection, malunion, nonunion, delayed union and patient discomfort necessitating extirpation of the materials fixed., Conclusion: We think that screw-wire combination technique is an easy and effective method with low cost and fast healing especially in reconstruction of anterior mandible fractures.

Thirty-two human mandibles were marked with three typical fracture lines: a low condylar fracture, a fracture of the mandibular angle, and one through the mental foramen on each side. The mandibles were sectioned at the fixation sites of the miniplate screws. The thickness of the cortical layer was measured with a scaled magnifying glass at the points of anthropological interest and at the marked screw holes. The inferior cortical layer turned out to be thickest in the anterior area. In contrast, it was very thin at the mandibular angle, which might explain the higher complication rate in treating fractures in this region. The thickness of the lingual cortex increased up to the symphysis, whereas the buccal cortical layer showed a decline in size from the mandibular angle up to the chin. The cortical bone at the alveolar ridge was porous. The cortical supply for miniplate osteosynthesis at the condylus ranged from 1.1 mm up to 1.74 mm, which seems to be limited, but due to the small diameter of the condylus most common screws obtain additional anchorage in the inner cortex. The thickness of the cortical layer at the mandibular angle increased from 1.47 mm at the ramus up to 1.97 mm at the beginning of the corpus, reaching 2.14-2.38 mm for the lower plate at the mental foramen. The results for the upper plate were slightly lower.

Objective: This study was carried out to evaluate clinical and radiologic results after lag-screw fixation (LSF) of mandibular parasymphyseal and angular fractures was performed., Study Design: Seven angle and 17 parasymphyseal fractures in 23 adult patients with mandibular fractures were treated by transoral reduction and LSF. Clinical and radiologic examinations were undertaken during a 3-month follow-up period, Results: All parasymphyseal fractures and four angular fractures went to good bone union after surgery. Infectious complications occurred in two patients with parasymphyseal fractures. These resolved with simple procedures. Three angular fractures needed refixing because of instability. Slight occlusal adjustment was needed in five patients. Postoperative neurosensory deficits were transient in every case in which they were seen., Conclusions: LSF of mandibular parasymphyseal fractures is a practical and effective way of fixing such fractures internally. It leads to good bone healing without permanent neurosensory deficit or increased risk of malocclusion. In mandibular angle fractures LSF is likely to be too technique-sensitive to allow its extensive use.

Objective: To test the effectiveness of lag screw fixation in their application in the treatment of mandibular fractures., Material and Methods: Sixty-nine mandibular fractures in 30 patients treated with lag screws were evaluated retrospectively regarding the cause, the type, and the site of fracture as well as the local situation and the complications encountered., Results: In 19 fractures a neutralization plate was used and in another 17 the lag screw was applied in combination with a compression plate. In 33 cases at least 3 lag screws were inserted. Seventy-five percent of the cases were in patients between 10 and 39 years old; 70% were the result of road traffic accidents. Most patients presented two mandibular fractures; the symphyseal area were most frequently affected. Teeth in the line of fracture were not removed, and no drains were used. Complications included two minor malocclusions, one delayed union, two cases of temporary paresis, two cases of transient hypesthesia, two cases of scar formation on the incision line, and a case of temporary trismus., Conclusions: Approximately 30% of the patients treated with lag screws according to the methods outlined in this study developed complications that were either minor, transient, or both; some were related to the approach rather than the method. The most frequent complications were minor malocclusions, transient facial paralysis, hypoesthesia, and scar formation.

We present 114 cases of mandibular angle fractures treated by screwed miniplates placed through a transbuccal incision with transbuccal trochar instrumentation. Usually patients were young men who suffered traffic accidents. The mean hospitalization time was 7 days. 94.5% of the patients healed without incident, no malocclusion complication was observed. Two postoperative hematomas required surgical drainage without healing complication. One non union required removal of the miniplate and maxillo-mandibular immobilization. 2 temporary postoperative hypoaesthesiae were observed. One patient presented a pericoronary infection of a third impacted molar, four months after surgery, but the fracture was healed. The comparison of the results with the others in the literature confirms the reliability of this technique.

Clinical, radiographic and electronic axiographic follow-up examinations were performed in 45 patients with a luxation or highly displaced fractures treated with traction screw fixation from 1984 to 1989. Axiographic findings gave an excellent objective evaluation of joint function. The excellent results achieved with traction screw fixation suggest that this method can be recommended for condyleal fractures of the mandible.

Almost a quarter of all mandibular fractures are located in the condylar neck region and generally lead to disturbances of occlusion. Because they still possess active growth centres, children and adolescents can take advantage of the joint's remodelling capacity following conservative treatment of these fractures. Fractures with displacement of the condylar head in adults can interfere with function if they are not surgically reduced (Krenkel and Strobl, 1989). In addition, a compensatory overloading of the non-fractured side, which originally goes unnoticed, can bring about disc pathology and chronic pain years later. For this reason, a surgical technique was developed for the management of mandibular condylar neck fractures. A new axial/oblique-axial lag screw (anchor screw) with biconcave washers (anchor washer) makes it possible to carry out standardized osteosynthesis in the region of the thin mandibular condyle neck. Functional exercises can be initiated immediately after the operation. There are three operative procedures using an extraoral approach (1-3) and two using an intraoral approach (4-5), depending on the type and severity of the fracture: 1. Direct anchor screw osteosynthesis with closed gliding hole. 2. Indirect anchor screw osteosynthesis with open gliding groove and safety plates. 3. Osteosynthesis with a 'slanted-screw' plate for longer oblique fractures. 4. Intraoral anchor screw method. 5. Intraoral anchor screw method with intraoral 'slanted-screw' plate. The functional long-term results of conservatively and surgically treated mandibular condylar neck fractures were objectively documented by means of mechanical and electronic axiography. The functional long-term results of the condylar neck fractures treated surgically were significantly better than those treated conservatively.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to determine whether the solitary lag screw technique meets the biomechanical demands of angle fractures. Simulated angle fractures in four cadaveric mandibles were reduced using solitary lag screws and the load-displacement relationships determined under functional loading of the individual mandibles. Subsequently, an angle fracture in a photoelastic mandible analog was fixed with a lag screw and subjected to similar loading. The mechanisms by which the solitary lag screw transferred functional loading were observed and recorded in a circular polariscope. Concomitant distraction tendencies were monitored and measured using displacement transducers. Correlation of the force-displacement measurements to photoelastic observation substantiated that the solitary lag screw functions as a tension band to provide a sufficient degree of interfragmentary compression and stability to withstand functional loading of the mandible.

This article presents a technique of applying lag screws for treating fractures of the mandibular angle. A review of 30 patients who had lag screws placed to treat such fractures showed that it is an extremely useful, but technique-sensitive, method of providing rigid internal fixation. The advantages and complications of this technique over bone-plate fixation are discussed.

The author reports 50 cases of fractures involving the angle of the mandible treated by traction screw fixation. The technique is described and the excellent results are analysed.

It is exceptional for surgery to become necessary after the use of miniaturized plate and screws. When it is required it is because of faulty reduction or contention, mucosal disunion or an infective focus, or a combination of these factors. Surgery provides good final results, but 2 to 4 supplementary months of immobility are needed, and it can be avoided by respecting the indications and practical necessities of this method.

Poly (L-lactide), a polymer of lactic acid (PLLA), with an extremely high molecular weight (Mv up to 1 x 10(6] has been synthesised under strictly controlled conditions resulting in a new microporous material with excellent mechanical properties. Bone-plates and screws machined from PLLA were used for fixation of two artificial mandibular fractures in sheep effected by a specially designed bone clamp. Fracture healing was uneventful without visible callus formation. Plates and screws of PLLA gave good stability over a sufficiently long period to enable normal fracture healing. Application in humans seems to be justified.