When a primary tooth is loosened, the process involves the resorption or dissolution of the roots, allowing the tooth to become mobile and eventually fall out. This resorption occurs because the body begins to signal for the primary tooth to make way for the permanent tooth that will replace it. Specialized cells called osteoclasts break down the roots of the primary tooth and the surrounding bone tissue, facilitating the natural tooth exfoliation process.
This physiological mechanism is crucial for maintaining proper alignment and spacing in the dental arch as the permanent teeth emerge. As the roots dissolve, the tooth becomes less stable and ultimately falls out, making space for the permanent tooth to erupt. This process is a normal part of dental development in children and ensures the proper transition from primary to permanent dentition.
The other options do not accurately represent the biological events occurring in this situation. The tooth does not simply fall out immediately without the resorption happening first, and it certainly does not reform; once the primary tooth is lost, it is replaced by a permanent tooth. Additionally, bone density typically does not increase in relation to a primary tooth loosening; rather, the bone around the tooth may resorb as the primary tooth roots dissolve.