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Chapter 7196four joints in which no reconstruction was performed. They performed a condylectomy and dissected the LPM from the anterior aspect of the condyle, then fixed the muscle to the anterior aspect of the condylar neck in the sigmoid notch region using 2 No 0 polyglactine 910 (Vicryl Ethicon, Sommverville, NJ, USA) sutures. They found significant differences in both laterotrusive and protrusive movements between the two patient groups; the patients who had a reconstruction had a better outcome. Despite these positive results, this research group did not publish more studies on this topic.(18) When Mommaerts examined the reconstruction of the LPM enthesis, on which this experiment was based, he found that a reinsertion of the LPM was possible, given the use of a titanium lattice structure in the condylar neck to allow for boney ingrowth.(7)When attempting to create bony ingrowth into a scaffold, specific conditions must be met to achieve a good outcome. The implant and scaffold surfaces need to be sufficiently osteoconductive to stimulate bone cell growth. The environment also needs to be osteoinductive to promote differentiation of mesenchymal stem cells (MSCs) into (pre)osteoblasts. Good osteogenesis also must also be achieved (i.e., sufficient MSCs, osteoblasts, and osteocytes need to be present). In a natural situation, the mandible is covered by periosteum, however when performing a resection and placing an implant, the periosteum can be lost. This difference is important because the inner layer of the periosteum (i.e., the cambium) includes differentiated osteogenic progenitor cells, fibroblasts, and osteoblasts.(19,20) The cambium has significant osteoblastic potential, which has a role during fracture healing. However, not all bones are covered by periosteum. Sesamoid bones (e.g., the patella) are not covered by periosteum, but are capable of osseous healing after a fracture.(21) As described by both Shapiro and Colnot, several types of bone repair can occur after a fracture.(22,23) The first and primary type is endochondral; a hematoma forms around the fracture, which is stabilized by the periosteum and the surrounding soft tissues. Cells from the cambium start proliferating and differentiating, and membranous ossification starts at the periphery of the fracture. Meanwhile, a central mass of cartilage is also formed. This mass ossifies via endochondral ossification. A clear Nikolas de Meurechy NW.indd 196 05-06-2024 10:14