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Open Access Prevention and Treatment Practice Issue
Orthodontic treatment of skeletal maxillary protrusion with dual bite: a case report and literature review
Journal of Prevention and Treatment for Stomatological Diseases 2026, 34(3): 263-272
Published: 20 March 2026
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Objective

To evaluate the clinical efficacy and stability of a centric relation (CR)-guided approach combined with micro-implant anchorage and long traction hooks for root-controlled retraction of the maxillary anterior teeth in a patient with skeletal maxillary protrusion and dual bite, and to provide a reference for clinical practice.

Methods

A case of a 29-year-old female patient with skeletal maxillary protrusion and an asymptomatic discrepancy between the maximum intercuspation position (MIP) and CR (dual bite) was reported. First, the CR was identified and obtained by cone beam computed tomography examination and clinical techniques, then was stabilized by glass ionomer bite registration and myofunctional training. Maintaining the CR, the maxillary micro-implants combined with long traction hooks were used to correct skeletal maxillary protrusion by facilitating maxillary anterior teeth retraction, and finally a new intercuspal occlusion was established to maintain long-term stability. A literature review was conducted to contextualize the treatment rationale and key steps.

Results

Post-treatment, a coordinated and stable functional occlusion was established in CR without temporomandibular joint symptoms, and the condylar location was coordinated with the glenoid fossa. Controlled root retraction of the maxillary anterior segment and facial profile improvement were achieved. At 3-year follow-up, both occlusion in the CR and condylar positions remained stable. The literature review indicated that, in patients with CR-MIP discrepancy, prioritizing the identification and stabilization of CR is critical, and micro-implant anchorage with long traction hooks effectively facilitates maxillary anterior teeth retraction and profile improvement.

Conclusion

For skeletal maxillary protrusion with dual bite, a CR-first strategy combined with micro-implant anchorage and long-hook mechanics for root-controlled anterior retraction can concurrently improve stomatognathic function and facial aesthetics, demonstrating favorable mid- to long-term stability.

Open Access Full Length Article Issue
Cdc42 deletion yielded enamel defects by disrupting mitochondria and producing reactive oxygen species in dental epithelium
Genes & Diseases 2024, 11(5): 101194
Published: 12 December 2023
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Developmental defects of enamel are common due to genetic and environmental factors before and after birth. Cdc42, a Rho family small GTPase, regulates prenatal tooth development in mice. However, its role in postnatal tooth development, especially enamel formation, remains elusive. Here, we investigated Cdc42 functions in mouse enamel development and tooth repair after birth. Cdc42 showed highly dynamic temporospatial patterns in the developing incisors, with robust expression in ameloblast and odontoblast layers. Strikingly, epithelium-specific Cdc42 deletion resulted in enamel defects in incisors. Ameloblast differentiation was inhibited, and hypomineralization of enamel was observed upon epithelial Cdc42 deletion. Proteomic analysis showed that abnormal mitochondrial components, phosphotransferase activity, and ion channel regulator activity occurred in the Cdc42 mutant dental epithelium. Reactive oxygen species accumulation was detected in the mutant mice, suggesting that abnormal oxidative stress occurred after Cdc42 depletion. Moreover, Cdc42 mutant mice showed delayed tooth repair and generated less calcified enamel. Mitochondrial dysfunction and abnormal oxygen consumption were evidenced by reduced Apool and Timm8a1 expression, increased Atp5j2 levels, and reactive oxygen species overproduction in the mutant repair epithelium. Epithelium-specific Cdc42 deletion attenuated ERK1/2 signaling in the labial cervical loop. Aberrant Sox2 expression in the mutant labial cervical loop after clipping might lead to delayed tooth repair. These findings suggested that mitochondrial dysfunction, up-regulated oxidative stress, and abnormal ion channel activity may be among multiple factors responsible for the observed enamel defects in Cdc42 mutant incisors. Overall, Cdc42 exerts multidimensional and pivotal roles in enamel development and is particularly required for ameloblast differentiation and enamel matrix formation.

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