RESUMO
External apical root resorption (EARR) is a common sequela of orthodontic treatment, although it may also occur in the absence of orthodontic treatment. The degree and severity of EARR associated with orthodontic treatment are multifactorial, involving host and environmental factors. Genetic factors account for at least 50% of the variation in EARR. Variation in the Interleukin 1 beta gene in orthodontically treated individuals accounts for 15% of the variation in EARR. Historical and contemporary evidence implicates injury to the periodontal ligament and supporting structures at the site of root compression following the application of orthodontic force as the earliest event leading to EARR. Decreased IL-1beta production in the case of IL-1B (+3953) allele 1 may result in relatively less catabolic bone modeling (resorption) at the cortical bone interface with the PDL, which may result in prolonged stress concentrated in the root of the tooth, triggering a cascade of fatigue-related events leading to root resorption. One mechanism of action for EARR may be mediated through impairment of alveolar resorption, resulting in prolonged stress and strain of the adjacent tooth root due to dynamic functional loads. Future estimation of susceptibility to EARR will likely require the analysis of a suite of genes, root morphology, skeleto-dental values, and the treatment method to be used-or essentially the amount of tooth movement planned for treatment.
Assuntos
Interleucina-1/genética , Aparelhos Ortodônticos/efeitos adversos , Reabsorção da Raiz/genética , Reabsorção da Raiz/metabolismo , Raiz Dentária/metabolismo , Animais , Osso e Ossos/metabolismo , Osso e Ossos/patologia , Osso e Ossos/fisiopatologia , Modelos Animais de Doenças , Arcada Osseodentária/metabolismo , Arcada Osseodentária/patologia , Arcada Osseodentária/fisiopatologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Reabsorção da Raiz/fisiopatologia , Estresse Mecânico , Raiz Dentária/patologia , Raiz Dentária/fisiopatologiaRESUMO
External apical root resorption (EARR) is a common orthodontic treatment sequela. Previous studies implicate a substantial genetic component for EARR. Using a candidate gene approach, we investigated possible linkage of EARR associated with orthodontic treatment with the TNSALP, TNFalpha, and TNFRSF11A gene loci. The sample was comprised of 38 American Caucasian families with a total of 79 siblings who completed comprehensive orthodontic treatment. EARR was assessed by means of pre- and post-treatment radiographs. Buccal swab cells were collected for extraction and analysis of DNA. No evidence of linkage was found with EARR and the TNFalpha and TNSALP genes. Non-parametric sibling pair linkage analysis identified evidence of linkage (LOD = 2.5; p = 0.02) of EARR affecting the maxillary central incisor with the microsatellite marker D18S64 (tightly linked to TNFRSF11A). This indicates that the TNFRSF11A locus, or another tightly linked gene, is associated with EARR.
