Table 6. Experimental studies about condylar head fractures in animals.
| Authors | Year | Animals | Fixation | Experiment | Result |
|---|---|---|---|---|---|
| Long and Goss20 | 2007 | 10 sheeps | An animal model was created for the vertical split fracture of the TMJ condylar head similar to a type B intracapsular condylar fracture in humans, and the mandibular function and morphological changes of the TMJ structure were evaluated | Our findings demonstrate that pathological changes of osteonecrosis, osteoarthrosis, and even ankylosis in the TMJ are likely to occur following vertical intracapsular fractures through the lateral condylar pole. This model can be used to evaluate various methods of surgical treatment | |
| Meng et al21 | 2010 | 8 sheeps | Two lateral screws (one lag screw and one position screw) | The aim of the present study was to compare and evaluate the veterinary and radiological outcomes of diacapitular condylar fracture after ORIF and closed treatment in the TMJ of sheep | The animals in the closed group had severely deformed condyles 12 wk after osteotomy. In contrast, animals in the ORIF group showed satisfactory reposition of the fractured fragments immediately after ORIF and well-shaped right condyles at 12 wk, with significantly fewer osteoarthrotic changes and signs of TMJ ankylosis |
| Schneider et al22 | 2011 | 20 pig mandibles | Ultrasound-aided resorbable pins with poly-(d,l)-lactide (SonicWeld Rx, KLS Martin, Tuttlingen, Germany) and titanium screws | The use of resorbable ultrasound-aided pins was compared with titanium screws to assess the biomechanical stability of osteosyntheses of artificially created diacapitular fractures of the condylar head in pigs. Stability of the osteosynthesis was assessed by a shear test using a universal strength-testing machine | An adequate level of clinical stability seems to support the use of pins in lowload-bearing osteosyntheses. The limiting factor is not the bonding between the pin and the host bone, but the strength of the pin itself. For this reason, increasing the number of pins will proportionally increase stability, though the difficulty in placing more than two pins in the narrow lateral pole of the condyle should be considered |
| Feng et al19 | 2012 | 12 Goats | A two-hole, 2-mm plate was attached with one screw to each fragment | Condylar cartilage from one randomly selected side of the condyle was removed while that on the other side was retained | A significant reduction of the ramus height was observed in the group from which the cartilage had been removed, in comparison with the control group in which it had been retained |
| Liu et al23 | 2012 | 20 sheeps | The lateral pterygoid muscle was cut (∼0.5–1.0 cm from each sheep in that group) in a group and a control group in which the muscle had not been cut was used | At 24 wk on CT scan, bone had overgrown the joints in which the muscle had not been cut, and the shape of the joints was less regular than previously. In contrast, the joints in which the muscle had been cut looked almost normal | |
| Schneider et al24 | 2013 | 20 sheeps | 2–3 resorbable SonicWeld pins in 10 animals. 2–3 conventional mini titanium screws in other 10 animals |
The use of resorbable ultrasound-aided pins was compared with titanium screws | The authors found no disadvantages of osteosynthesis with pins compared with titanium screws. Advantages of the resorbable material (ability to degrade and no material to remove) seemed to predominate, thus supporting the use of sonic welding for fractures of the condylar head in humans |
Abbreviation: TMJ, temporomandibular joint.