# Cell Death in Orthodontic Tooth Movement: Recent Advances and Emerging Insights

## TL;DR

This paper reviews how different types of cell death help control bone changes during orthodontic tooth movement.

## Contribution

It highlights novel regulated cell death pathways beyond apoptosis and necrosis in orthodontic tooth movement.

## Key findings

- Regulated cell death pathways like pyroptosis and ferroptosis influence bone resorption during tooth movement.
- Autophagy supports tissue repair and osteogenesis on the tension side of tooth movement.
- Cell death actively regulates alveolar bone remodeling rather than being a passive process.

## Abstract

Orthodontic tooth movement (OTM), a complex biological process driven by orchestrated bone remodeling, involves osteoclastic bone resorption and osteoblastic bone formation in response to mechanical force. Traditionally, OTM-related cell death has been discussed in terms of apoptosis and necrosis. However, recent advances in cell death research have revealed various forms of regulated cell death (RCD) beyond these conventional categories. This review summarizes the current understanding of the diverse RCD pathways and their roles in various cell populations during OTM. It delineates the involvement of distinct RCD mechanisms, including apoptosis, autophagy, pyroptosis, ferroptosis, and necroptosis. On the compression side, these RCD pathways in periodontal ligament (PDL) cells, cementoblasts, cementocytes, and bone-related cells actively drive inflammatory responses, promote bone resorption, and contribute to root resorption. Conversely, on the tension side, specific RCD pathways, notably autophagy in the PDL and osteocytes, play crucial roles in promoting osteogenesis and tissue repair. Collectively, cell death is not merely a passive elimination of cells but actively functions as a critical switch for alveolar bone remodeling during OTM. Understanding these multifaceted RCD mechanisms provides novel insights into the biological regulation of tooth movement and identifies potential therapeutic targets for enhancing tooth movement efficiency and mitigating adverse effects.