This protocol provides a murine mandibular molar extraction model that is rarely introduced in available bone regeneration studies. Developing a murine mandibular molar extraction model is necessary as a mandible that is a more comparable and consistent among different intervention groups. The implications of this technique do not extend toward the therapy of any disease.
However, it may help clinical healing and jaw bone regeneration in the long range by helping review the mechanisms underlying this process. This technique was developed to help the studies, revealing the mechanisms of available healing and regeneration. Regretfully, this method cannot be applied to other systems.
Begin eliminating the distal resistance of the anesthetized mouse by holding the molar with tweezers medially. Then force a 23 gauge needle into the buccal alveolar bone of the distal root and render an interval. Next, change to a 25 gauge needle to continue the interval expansion.
Progress delicately toward the periapical area while slowly rotating the needle forward and langually to press the root out of the alveolar fossa. To eliminate the mesial resistance, insert a 23 gauge needle into the root fork and lift the molar of occlusally. After holding the molar tightly take another 23 gauge needle and force it into the lingual mesial periodontal membrane to create an interval.
Then use a 25 gauge needle and slowly rotate forward and buccally. If some underlying hindrances impede the luxation of the molar, use a 26 gauge needle to penetrate the root apex and repeat the operations. During the final extraction, extract the tooth ensuring that the crown rises above the occlusal plane and that two intact roots can clearly be seen.
After successfully extracting the mandibular first molar, apply dry cotton to stop the bleeding, reposition the tongue, administer analgesia, and put the mouse on a constant temperature heating pad until it recovers from anesthesia. The tooth socket immediately filled with clot post extraction. The healing process of the socket was observed for one week.
Some sponge-like trabecular bones were formed but the clot remained. In the healing process, the socket was filled with sponge bones after two weeks indicating the completion of regeneration. A master regulator in osteoblast differentiations Sp7 was widely expressed in the bone marrow cells in the margin which is the bone forming front.
Under the homeostasis state the trabecular bones were consistent and confluent with bone marrow cell blocks sprinkled like islands. At one week post-surgery, numerous Sp7 expressing cells filled the extraction socket with newly formed trabecular bone sprinkled around. At four weeks post-surgery, the condition reversed and turned to largely merge to trabecular bone.
The activity of Sp7 expressing cells declined to a level approaching the homeostasis state. The can also be performed to demonstrate the newborn regeneration process. This technique can help researchers unravel the underlying mechanisms of available healing and regeneration process by providing a new murine model.
