Mouth breathing impairs the development of temporomandibular joint at a very early stage

Abstract

Objectives The study aimed to explore the effects of mouth breathing and hypoxia on the condyle of temporomandibular joint (TMJ) via two animal models. Methods 24 four‐week‐old rats were randomly separated into three groups, consisting of eight control rats, eight intermittent hypoxia (IH) rats, and eight intermittent nasal obstruction (INO) rats. We use the IH model and the INO model to simulate children suffering from hypoxia and mouth breathing. After 16 days, the condyle of TMJ and surrounding white adipose tissue (WAT) and skeletal muscle tissue were obtained for further staining and qRT‐PCR. Finally, RNA‐seq was used to verify the results. Results The intermittent hypoxia cannot significantly change the overall structure in the cause of short‐term hypoxia stimulation, but the intermittent nasal obstruction can alter the condyle, WAT, and muscle, while also introducing noticeable structural changes in tissue hypoxia and macrophage infiltration. Sequencing data verified these findings and also suggested that this process might involve the Hif‐1α/Vegf axis. Conclusions Our findings reveal the very early structural impact of mouth breathing on condyle reconstruction in rat models, and hypoxia does not induce evident alteration on condyle. However, since these results are mainly focused on rats, further studies are needed to understand its effects on humans.

The impact of mouth breathing on dentofacial development: A concise review

“…In an intermittent nasal congestion rat model, there was a significant reduction in the thickness of the hyperplasia layer as well as the hypertrophic layer of condylar joint, which suggested that the development of the temporomandibular joint was also influenced by oral breathing habits ( 63 ). A previous randomized controlled trial ( 64 ) established another bilateral rat model of intermittent nasal congestion, and it found that mouth breathing would lead to defects in condylar development during adolescence, with the mechanism that chondrogenic differentiation of condylar mesenchymal stem cells was inhibited.…”

Excessive load promotes temporomandibular joint chondrocyte apoptosis via Piezo1/endoplasmic reticulum stress pathway

“…Altered mechanical stresses on the joint due to mouth breathing may impact condylar development. 5 Mechanical pressure alters signalling in chondrocytes, affecting cartilage maintenance, degradation, and regeneration. This plays a crucial role in the pathogenesis of osteoarthritis.…”

“…[1][2][3][4] A close relationship exists between excessive loads and TMJOA.Altered mechanical stresses on the joint due to mouth breathing may impact condylar development. 5 Mechanical pressure alters signalling in chondrocytes, affecting cartilage maintenance, degradation,…”

Do symptoms and signs of temporomandibular disorders have an association with breathing pattern: a cross-sectional study on Turkish children and adolescents

“…MB is considered to cause growth disturbance in the structures of the craniofacial complex [ 17 , 19 , 26 , 28 ]. Recent experimental studies suggested that MB impairs the development of TMJ in early stages [ 18 , 29 ]. Based on these, the authors hypothesized that individuals with MB may tend to have TMD signs/symptoms more commonly and there can be a link between MB and TMD.…”