Richard Loukota

Fractures of the mandibular condyle: evidence base and current concepts of management

Management of mandibular condylar fractures remains a source of ongoing controversy. While some condylar fractures can be managed non-surgically, recognition of fracture patterns that require surgical intervention and selection of an appropriate operative procedure are paramount to success in treating these injuries.The objective of this review is to appraise the current evidence regarding the effectiveness of interventions that are used in the management of fractures of the mandibular condyle.

Comparative evaluation of ten different condylar base fracture osteosynthesis techniques

The aim of this study on the mandibles of minipigs was to compare the biomechanical stability of different methods of osteosynthesis that are used in the operative treatment of fractures of the base of the condyle. Ten different systems of osteosynthesis were used to fix 164 fractures, which were tested by a two-point bending test after repositioning and fixing. This stress test was applied in four directions: lateral to medial, anterior to distal, distal to anterior, and medial to lateral. The Eckelt lag screw, one or two 2.0mm miniplates, one miniplate with bar (KLS Martin), minicompression plates (Medicon), zygoma compression plates (Medartis), condylus fracture plates (Medartis), square 4-hole plates (KLS Martin), and either one or two resorbable 4-hole miniplates (Resorb-X, Martin) were used for osteosynthesis. A total of 164 tests were done using a universal test machine that measured forces until the osteosynthesis failed. Advantages in mechanical load capacity were also measured for the Eckelt lag screw when force was applied from medial to lateral. Fixation with one resorbable miniplate was not functionally stable. Irrespective of the direction of force applied, two miniplates were the most stable technique. There were pronounced differences depending on the direction of force applied. The results suggest that treatment with a single resorbable miniplate is not functionally stable.

Histologic study of incorporation and resorption of a bone cement–collagen composite: an in vivo study in the minipig

OBJECTIVE Calcium phosphates are clinically established as bone defect fillers. They have the capability of osseoconduction and are characterized by a slow resorption process. The present study evaluated the suitability of a newly developed calcium phosphate cement modified with collagen type I. STUDY DESIGN The modified cement paste was inserted in differently designed defects of 10 minipigs. Further, an alveolar ridge augmentation was performed, applying the cement paste. The cement hardened in situ during the operation, forming a hydroxyapatite collagen composite. Animals were sacrificed after 1, 3, 6, 12, and 18 months. The tissue integration and resorption process was then evaluated using nondecalcified microsections. All animals were evaluated for histology. RESULTS The implanted material showed osseoconductive characteristics. Resorption started from the edge of the defect zone, and bone substitution followed rapidly. Twelve months after placement of the cement, complete remodeling was observed. CONCLUSION It can be concluded that the applied hydroxyapatite-collagen cement composite shows good resorption and bone integration.

Biomechanical evaluation of a titanium implant surface conditioned by a hydroxide ion solution

Two groups of titanium dental implants, identical in geometry but different in the treatment of their surfaces, were tested in an in vivo minipig model of the mandible. The surfaces that were tested were, first, sandblasted and acid-etched; and secondly, sandblasted, acid-etched, and conditioned. The removal torque was assessed at 2, 4, and 8 weeks after implantation (n=6 animals in each healing period). The interfacial stiffness was also evaluated. All dental implants were well-integrated at the time of death. Removal torque values increased significantly over the course of 8 weeks. Removal torque and interfacial stiffness were increased for conditioned surfaces after 2 weeks, but there were no significant differences between the two surfaces. The sandblasted and acid-etched implants are the standard, and conditioning of the surface showed a tendency to increase early peri-implant formation of bone.

Fixation of comminuted diacapitular fractures of the mandibular condyle with ultrasound-activated resorbable pins.

We describe the fixation of bilateral comminuted diacapitular fractures of the mandibular condyle with ultrasound activated resorbable pins (KLS Martin SonicWeld Rx) by an open approach with primary fixation of the fractures using the resorbable osteosynthesis pins.

Stability of fixation of diacapitular fractures of the mandibular condylar process by ultrasound-aided resorbable pins (SonicWeld Rx® System) in pigs

To assess the stability of osteosynthesis in diacapitular condylar fractures we compared fixation using ultrasound-aided resorbable pins with poly-(D,L)-lactide (SonicWeld® Rx, KLS Martin, Tuttlingen, Germany) with that of titanium screws in 20 pig mandibles, 10 in each group. Isolated diacapitular fractures were created using a surgical chisel. Ten fractures were each repositioned and fixed by two pins (17 and 11 mm long, 2.1mm in diameter), and 10 fractures were fixed by two titanium screws of equal length, 2.0mm in diameter. Shear tests were done immediately after treatment to measure the maximum force to disrupt the fixation. Fixation with pins resisted mean shear forces of 310N until the pins fractured, whereas fixation with titanium screws failed at 918N when the screws pulled out of the bone. Long-term stability and resorption of pins will have to be analysed in an in vivo study.

Tapia's syndrome after repair of a fractured mandible

A 41-year-old gentleman underwent surgical repair of the fractured right parasymphisis and left condyle of his mandible. Post-operatively he developed hoarseness of voice and dyspnoea during speech, with deviation of the tongue on protrusion. After excluding intracranial and surgical causes, a clinical diagnosis of Tapias syndrome was made.

INION compared with titanium osteosynthesis: a prospective investigation of the treatment of mandibular fractures.

We prospectively studied two groups of 30 patients to assess the outcome of treatment of mandibular fractures with the biodegradable INION system compared with osteosynthesis with titanium miniplates. The degree of occlusion, wound healing, and swelling, were noted preoperatively and at 1 week, 6 weeks, and 6 months postoperatively. All fractures healed uneventfully, both clinically and radiologically, and independently of the osteosynthesis used. We found no long-term disturbance of occlusion, but there were twice as many malocclusions in the INION group at one week. We now use a 3-5 day period of postoperative elastic intermaxillary fixation (IMF) to prevent material deformities. Both groups developed problems with wound healing; with INION adequate soft tissue closure combined with appropriate positioning of the plates prevented this. At 6 months a dense swelling developed in some patients in the INION group as a result of biodegradation of the plates. INION plates were biocompatible and strong enough to treat mandibular fractures.

Resorbable triangular plate for osteosynthesis of fractures of the condylar neck

We describe a new design of resorbable plate for use in the treatment of fractures of the condylar neck, and report the outcome of initial treatment in two patients.

Reduction of diacapitular fractures of the mandibular condyle using a special repositioning pin

t a t r r m osteosynthesis screws, the resistance conferred by the pin is sufficient to maintain the condylar fragment in the correct position. he reduction of diacapitular fractures1 of the mandibuar condyle can be technically difficult and time-consuming ut seems to have a beneficial effect on patients.2,3 The roximal condylar fragment is often considerably displaced edially and caudally by the pull of the lateral pterygoid musle. Disruption of soft tissue should be kept to a minimum o compromise the blood supply to the proximal fragment s little as possible.4 Previously such a fractures has been educed using small bone hooks, so a new repositioning pin o assist in reduction and fixation of the proximal condylar ragment with only minimal dissection has therefore been eveloped. The pin is held in the metal handle of a mini-screwdriver. nstead of the usual screw head, a 10 mm thread, equivalent o that of a 2 mm miniscrew, is located at the end of the 7 cm haft. The shaft can easily be released from the handle by a ayonet nut. After exposure of the condylar fragment, it is rilled with a drill10 mm long and 1.8 mm in diameter on the orsal surface. The pin can then be inserted. Using pharmaological muscle relaxation, the resistance of the contracted ateral pterygoid muscle can be overcome without difficulty nd the fragment can be slowly reduced. After the correct osition has been achieved, the bone is fixed, in most cases