Final answer:
The alveolar process of the mandible forms the inferior border of spongy bone that supports the teeth's roots. Teeth are anchored by a gomphosis joint, with the periodontal ligament connecting the roots to the bony sockets, providing support and stress distribution.
Step-by-step explanation:
The inferior borders of spongy bone that support the roots of the teeth are found in the alveolar process of the mandible. This structure is pivotal because it provides a strong yet flexible foundation for the teeth, allowing them to withstand the forces of chewing and biting. Teeth are held securely within their sockets (alveoli) by the alveolar processes of both the maxilla and the mandible. The alveolar process of the mandible is the upper border of the mandibular body and specifically serves to anchor the lower teeth. Furthermore, the roots of the teeth are embedded within the spongy bone, surrounded by dentin and covered by cementum.
Each tooth is anchored into its socket by a specialized fibrous joint known as a gomphosis, where numerous short bands of dense connective tissue known as the periodontal ligament span the bony socket walls and the root of the tooth. These ligaments, alongside the structural composition of spongy bone, adapt to the stresses from various directions, similar to the cushioning effect in the epiphyses of long bones such as the femur.
The importance of the alveolar process and periodontal ligaments in dental health is crucial. They not only act as a support frame for the teeth but also absorb and redistribute the various stresses experienced during mastication, helping to maintain the integrity of the craniofacial structure.