Comparison of invisalign mandibular advancement and twin-block on upper airway and hyoid bone position improvements for skeletal class II children: a retrospective study.

BACKGROUND: This study is to evaluate and compare the improvement of upper airway morphology and hyoid bone position in children with Class II mandibular retrusion treated with Invisalign mandibular advancement (MA) and Twin-Block (TB) appliances, utilizing cone beam computed tomography (CBCT). METHODS: 32 children aged between 8 and 11.5 years old were included in this study, with an average age of 10.2 years old. These children were divided into two groups, MA and TB, with 16 children in each group. Changes in upper airway morphology and hyoid bone position before and after treatment were analyzed using CBCT. RESULTS: (1) Changes in upper airway before and after treatment: the oropharynx volume (Or-V), the oropharynx minimum cross-sectional area (Or-mCSA), the hypopharynx volume (Hy-V), and the hypopharynx minimum cross-sectional area (Hy-mCSA) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05) compared to pre-treatment status. (2) Changes in hyoid bone position before and after treatment: The distances between H point and third cervical vertebra (H-C3), H point and pogonion (H-RGN), H point and mandibular plane (H-MP), H point and Frankfort horizontal plane (H-FH), H and S point (H-S), and H point and palatal plane (H-PP) in both the MA and TB groups increased after treatment, and the differences were statistically significant (P < 0.05). CONCLUSION: Both MA and TB appliances effectively improved the structural narrowness of the upper airway and reduced respiratory resistance, thus improving breath quality. However, MA showed more effectiveness in improving the narrowest part of the hypopharynx compared to TB. Both appliances also promoted anterior downward movement of the hyoid bone, which opens the upper airway of the oropharynx and hypopharynx and helps the upper airway morphology return to normal range.

Exendin­4 promotes osteogenic differentiation of adipose­derived stem cells and facilitates bone repair.

Inflammation­related bone defects pose a heavy burden on patients and orthopedic surgeons. Although stem­cell­based bone repair has developed rapidly, it is of great significance to characterize bio­active molecules that facilitate bone regeneration. It is reported that a glucagon­like peptide 1 receptor agonist, exendin­4, promoted bone regeneration mediated by the transplantation of adipose­derived stem cells in a metaphyseal defect mouse model of femur injury. However, the underlying mechanism is unclear. Bone imaging, immunohistochemistry real­time PCR and western blot analysis were used in the present study, and the results revealed that exendin­4 increased the transcription of the osteogenic differentiation­related genes and induced osteogenic differentiation in situ. Furthermore, the present data obtained from sorted adipose­derived stem cells revealed that exendin­4 promoted osteogenic differentiation and inhibited adipogenic differentiation in vitro. These findings indicated that exendin­4 facilitates osteogenic differentiation of transplanted adipose­derived stem cells for bone repair and illuminated clinical prospects of both adipose­derived stem cells and exendin­4 in stem­cell­based bone defect repair.