Physiological Mechanisms of Root Resorption in Deciduous Teeth

Physiological root resorption in deciduous teeth is an orchestrated, cell-mediated process essential for normal exfoliation and permanent tooth eruption. This process involves the coordinated removal of mineralised tissues—dentine and cementum—by specialised clastic cells, known as odontoclasts, alongside the elimination of pulpal and periodontal ligament (PDL) tissues. The initiation phase is characterised by apoptosis of cementoblasts and PDL cells, exposing underlying hard tissues that attract monocyte-derived precursors. Local regulation centres on the balance between receptor activator of nuclear factor kappa-B ligand (RANKL) and its decoy receptor osteoprotegerin (OPG), which governs odontoclast differentiation and activity. Inflammatory mediators such as interleukins and prostaglandins, together with mechanical stimuli from occlusal forces, modulate the resorptive microenvironment, influencing the expression of matrix metalloproteinases (notably MMP9) and signalling pathways including Wnt/β-catenin. These dynamic interactions ensure a controlled, site-specific resorption that paves the way for permanent dentition, with implications for orthodontic treatment timing, paediatric oral health and the development of novel therapeutic strategies to manage premature or pathological resorption.

Research from Nature Portfolio

Recent studies have elucidated molecular regulators of odontoclastogenesis. Investigations into the RANKL/OPG axis in damaged dental pulp tissue reveal that an elevated RANKL/OPG ratio is critical to activating odontoclast-like cells, with hypoxia-inducible factors further tilting this balance under stress conditions. Moreover, transcriptomic profiling in a feline model of tooth resorption identified upregulation of matrix metalloproteinase 9 as a pivotal driver of clastic activity, offering insight into conserved enzymatic pathways that may underlie physiological resorption in deciduous teeth.

Physiological Mechanisms of Root Resorption in Deciduous Teeth publication trend

The graph below shows the total number of articles in physiological mechanisms of root resorption in deciduous teeth across all publications each year (not limited to Nature Index journals).

Technical terms

Odontoclast: A multinucleated cell derived from monocytes that actively resorbs dental hard tissues.

Receptor activator of nuclear factor kappa-B ligand (RANKL): A cytokine essential for clastic cell differentiation and activation.

Osteoprotegerin (OPG): A soluble decoy receptor that binds RANKL, inhibiting clastic cell formation.

Periodontal ligament (PDL): A fibrous connective tissue anchoring the tooth root to alveolar bone.

Matrix metalloproteinase 9 (MMP9): An enzyme that degrades extracellular matrix components during tissue remodelling.

α7 Nicotinic acetylcholine receptor (α7 nAChR): A receptor whose activation modulates signalling pathways in PDL cells under mechanical stress.

Apoptosis: Programmed cell death that initiates exposure of root surfaces to resorptive cells.

References

1. RANKL/OPG ratio regulates odontoclastogenesis in damaged dental pulp. Scientific Reports (2021).
2. Advances in the Study of the Mechanisms of Physiological Root Resorption in Deciduous Teeth. Frontiers in Pediatrics (2022).
3. Mechanical Stress Modulates the RANKL/OPG System of Periodontal Ligament Stem Cells via α7 nAChR in Human Deciduous Teeth: An In Vitro Study. Stem Cells International (2019).
4. Transcriptomic profiling of feline teeth highlights the role of matrix metalloproteinase 9 (MMP9) in tooth resorption. Scientific Reports (2020).
5. Mechanisms and substances involved in clastic activity of root resorptions – literature review. Research Society and Development (2022).