Gums, formally known as gingiva, are soft tissues and do not contain bone material. They serve as a protective covering for the harder structures underneath. This soft tissue provides a seal around the teeth, shielding the underlying jawbone from the harsh oral environment.
Defining the Gums and Underlying Bone
The mouth contains a distinct separation between soft and hard tissues that work together to support the teeth. The gum tissue, or gingiva, is a dense, vascularized layer of epithelial and connective tissue. This robust structure functions primarily to protect the delicate tissues and bone below from bacteria and physical forces like chewing. Specifically, the attached gingiva is firmly bound to the underlying bone, creating a stable, resilient barrier.
Beneath the attached gum tissue lies the periosteum, a connective tissue membrane. The periosteum wraps around the outer surface of the jawbone and contains blood vessels and nerves. This layer supplies nutrients to the bone and facilitates bone growth and repair. Together, the gum tissue and the periosteum form a protective cushion over the hard skeletal structure.
The Role of the Jawbone in Oral Health
The bone beneath the gums is the jawbone, which includes the specialized section called the alveolar process. This alveolar bone is solely responsible for housing and supporting the teeth. It forms the tooth sockets, or alveoli, which are hollow spaces where the tooth roots are anchored by the periodontal ligaments.
The density and health of the alveolar bone are directly linked to the stability of the teeth. Cells called osteoblasts build new bone, while osteoclasts break down old bone tissue in a continuous cycle. This remodeling process allows the bone to adapt to the forces of chewing and maintain its supportive structure.
Why Bone Can Sometimes Be Felt or Seen
While gums typically cover the bone completely, there are specific situations where a hard structure can be felt or even seen through the soft tissue. One common cause is gum recession. As the gums pull away from the tooth, the root surface and sometimes the underlying alveolar bone can become exposed. This exposure can make the area feel hard and rough to the touch.
Another cause of a hard area is a benign bony growth called an exostosis or a bone spur. These are typically smooth, slow-growing protrusions of bone that develop on the jawbone surface, making the overlying gum feel firm. Following a tooth extraction, small, sharp fragments of bone called spicules may sometimes work their way out of the healing socket. These fragments can poke through the gum tissue, causing a rough or sharp sensation.