Final answer:
The most common area in the maxillofacial region for breast cancer to metastasize is the posterior mandible.
Step-by-step explanation:
The most common infrabony site for breast cancer to metastasize to the maxillofacial region is the posterior mandible. The maxillary bone, or maxilla, while significant in the oral cavity's anatomy, is not the predominant site for such metastases. Breast cancer can metastasize to various parts of the body, and while certain cancers have preferred metastatic sites, the posterior mandible is known to be a more common site for metastatic spread in the maxillofacial region compared to locations such as the anterior maxilla, anterior mandible, posterior maxilla, or hard palate.