The body's endogenous opioid peptide systems naturally suppress inflammation in tooth pulp during orthodontic treatment, but excessive forces can overwhelm these defenses and cause irreversible pulp damage.
38 studies reviewedThis systematic review synthesized 38 studies examining how endogenous opioid peptides modulate inflammation in dental pulp during orthodontic treatment, providing the most comprehensive assessment of this mechanism to date.
What the researchers found
Endogenous opioid systems — including somatostatin, dynorphin, β-endorphin, methionine enkephalin, endocannabinoids, and anti-inflammatory cytokines — modulate neurogenic inflammation in the dental pulp triggered by orthodontic forces. This explains why most patients experience minimal pain during orthodontic treatment despite the release of pro-inflammatory neuropeptides (Substance P, CGRP, Neurokinin A). However, when severe orthodontic forces are applied, these endogenous control mechanisms may be overwhelmed, leading to asymptomatic irreversible pulpitis or pulp necrosis.
Why it matters
Orthodontic pain management has largely relied on external painkillers, but understanding the body's own opioid peptide systems reveals natural anti-inflammatory pathways that could be harnessed therapeutically. This knowledge could lead to better pain management strategies during orthodontic treatment and help identify patients at risk of pulp damage from excessive forces.
How the study worked
Systematic literature review following PRISMA and AMSTAR guidelines, searching PubMed, ISI Web of Science, and Scopus using keywords for orthodontic movement, opioids, and neurogenic inflammation. After removing duplicates and applying inclusion criteria, 38 articles were selected and classified by the opioid peptides analyzed in relation to orthodontic movement and dental pulp.
Who was studied
Review of 38 studies examining opioid peptide mechanisms in dental pulp during orthodontic treatment
What this study cannot tell us
The review synthesizes primarily preclinical and mechanistic studies — direct clinical evidence linking endogenous opioid activity to orthodontic pain outcomes in patients is limited. The 38 included studies likely vary in methodology and quality. The review does not quantify the protective threshold at which endogenous systems become insufficient against severe orthodontic forces.
How to read the evidence
This is a systematic review following PRISMA/AMSTAR guidelines, which represents a high level of evidence synthesis methodology. However, the underlying studies are primarily mechanistic and preclinical rather than clinical outcome trials, limiting the strength of clinical conclusions.
When this study was published
Published in 2025, this is a very current review that provides an up-to-date synthesis of the literature on endogenous opioid modulation in dental pulp inflammation.
The bigger picture
This review bridges two fields — orthodontics and neuropeptide biology — revealing that the dental pulp has a sophisticated endogenous pain control system involving multiple peptide pathways. Understanding these mechanisms has implications beyond orthodontics: it contributes to the broader understanding of how opioid peptides regulate inflammation throughout the body and could inform pain management strategies that work with, rather than against, the body's natural defense systems.
Questions still open
- Could measuring opioid peptide levels in dental pulp fluid help predict which patients are at risk of pulp damage during orthodontic treatment?
- Is there a threshold of orthodontic force below which the endogenous opioid system reliably prevents pulp damage?
- Could pharmacological enhancement of endogenous opioid pathways improve pain control and reduce pulp damage risk during aggressive orthodontic treatment?
Common questions
Why don't most people feel severe pain during orthodontic treatment even though it causes inflammation?
Can orthodontic treatment damage tooth nerves without causing pain?
Read the original research
The role of the endogenous opioid system in modulating orthodontic-induced neurogenic inflammation of the dental pulp: A comprehensive review of the literature.
International endodontic journal, 58(8), 1126-1145
Citation
Caviedes-Bucheli, Javier; Rios-Osorio, Nestor; Ulate-Rodríguez, Esteban; Muñoz-Alvear, Hernan Dario; Gaviño-Orduña, José F; Ortolani-Seltenerich, P Sebastian; Gomez-Sosa, Jose F; Munoz, Hugo Roberto. (2025). The role of the endogenous opioid system in modulating orthodontic-induced neurogenic inflammation of the dental pulp: A comprehensive review of the literature.. International endodontic journal, 58(8), 1126-1145. https://doi.org/10.1111/iej.14251