Is Inflammation a Friend or Foe for Orthodontic Treatment?: Inflammation in Orthodontically Induced Inflammatory Root Resorption and Accelerating Tooth Movement.

Masaru Yamaguchi,Shinichi Fukasawa

doi:10.3390/ijms22052388

Abstract

The aim of this paper is to provide a review on the role of inflammation in orthodontically induced inflammatory root resorption (OIIRR) and accelerating orthodontic tooth movement (AOTM) in orthodontic treatment. Orthodontic tooth movement (OTM) is stimulated by remodeling of the periodontal ligament (PDL) and alveolar bone. These remodeling activities and tooth displacement are involved in the occurrence of an inflammatory process in the periodontium, in response to orthodontic forces. Inflammatory mediators such as prostaglandins (PGs), interleukins (Ils; IL-1, -6, -17), the tumor necrosis factor (TNF)-α superfamily, and receptor activator of nuclear factor (RANK)/RANK ligand (RANKL)/osteoprotegerin (OPG) are increased in the PDL during OTM. OIIRR is one of the accidental symptoms, and inflammatory mediators have been detected in resorbed roots, PDL, and alveolar bone exposed to heavy orthodontic force. Therefore, these inflammatory mediators are involved with the occurrence of OIIRR during orthodontic tooth movement. On the contrary, regional accelerating phenomenon (RAP) occurs after fractures and surgery such as osteotomies or bone grafting, and bone healing is accelerated by increasing osteoclasts and osteoblasts. Recently, tooth movement after surgical procedures such as corticotomy, corticision, piezocision, and micro-osteoperforation might be accelerated by RAP, which increases the bone metabolism. Therefore, inflammation may be involved in accelerated OTM (AOTM). The knowledge of inflammation during orthodontic treatment could be used in preventing OIIRR and AOTM.

Highlights

Orthodontic tooth movement (OTM) is stimulated by remodeling of the periodontal ligament (PDL) and alveolar bone. These remodeling activities and tooth displacement are involved in the occurrence of an inflammatory process in the PDL and alveolar bone, in response to orthodontic forces
Low et al [105] reported that heavy force induces RANK and OPG in rat experimental tooth movement, which are involved with the occurrence of orthodontically induced inflammatory root resorption (OIIRR)
IL-6, IL-8, are IL-17 can be detected in resorbed root exposure to heavy forces in rat experimental tooth movement, and these cytokines may be involved in the occurrence of OIIRR [100,106,107] (Figures 5 and 6)

Summary

Introduction

Orthodontic tooth movement (OTM) is stimulated by remodeling of the periodontal ligament (PDL) and alveolar bone. Cellular changes in PDL were the first events, and inflammatory mediators such as prostaglandins (PGs), interleukins (ILs; IL-1, -6, and -17), the tumor necrosis factor (TNF)-α superfamily, and the receptor activator of nuclear factor (RANK)/ RANK ligand (RANKL)/osteoprotegerin (OPG) increased in the periodontium. Their increased levels during OTM lead to biological responses that occur following the application of orthodontic forces [1]. The cause of OIIRR is unknown, it is thought that complex inflammatory processes that involve various factors, such as mechanical forces, morphology of tooth roots, alveolar bone, PDL, cementum, and certain known biological messengers, are involved [3]. We review current knowledge regarding inflammation in OIIRR and AOTM

Optimal Orthodontic Force

Cytokines

Treatment Alternatives

Treatment Progress

Case Summary