Orthodontics & Craniofacial Research最新文献

Families studies conducted in different ethnic populations worldwide have helped elucidate the molecular and genetic factors involved in the development of skeletal class III malocclusion. Therefore, the aim of this study is to provide an updated summary. The study followed the JBI Manual for Evidence Synthesis and PRISMA-scR guidelines. PubMed, Scopus, WOS, Google Scholar and DANS databases were explored using specific strategies. Eligible studies included linkage and genome-wide analyses, while association studies, case reports and in vivo/in vitro research were excluded. The included studies must have involved at least one family with one or more members exhibiting the skeletal malocclusion phenotypes. An autosomal dominant inheritance pattern with variable penetrance for skeletal class III malocclusions across East Asian, Southeast Asian, Middle Eastern, European and South American populations was identified. In contrast, skeletal class II malocclusions exhibited autosomal dominant and X-linked inheritance patterns, with a higher prevalence in Eastern Mediterranean and South American populations. Key molecular findings include missense mutations in DUSP6 (c.545C>T and c.1094C>T), which affect mandibular prognathism and maxillary deficiency via the FGF/FGFR and MAPK/ERK pathways. Additionally, mutations in ADAMTS1 (c.742I>T), ADAMTS2 (c.3506G>T) and ADAMTSL1 (c.176G>A) impact mandibular growth through aggrecan metabolism and osteogenesis, disrupting bone remodelling via the EGFR/ErbB signalling pathway. This comprehensive review highlights the complex genetic basis of skeletal malocclusions, provides insights into the underlying molecular mechanisms, suggests potential targets for therapeutic intervention, and contributes to our understanding of the genetic architecture of these conditions.

Objective: This retrospective study compared the skeletal and dental effects of the Invisalign Mandibular Advancement Appliance with Enhanced Precision Wings (MA-EPW) and the conventional Twin Block (TB) in growing patients with skeletal Class II malocclusion.

Materials and methods: Thirty-two patients (TB: n = 18; MA-EPW: n = 14) were included. Pre- and post-treatment cephalometric radiographs and digital models were analysed to assess skeletal, dental and transverse changes. Statistical analysis was performed using parametric and non-parametric tests, with significance set at p < 0.05.

Results: Both appliances improved ANB angle, Wits appraisal, overjet and overbite, with no significant intergroup differences in skeletal correction. The MA-EPW group showed greater maxillary and mandibular transverse expansion and better maintenance of lower incisor inclination, whereas the TB group exhibited greater proclination of the lower incisors. The observation period was longer in the MA-EPW group.

Conclusion: Both TB and Invisalign MA-EPW appliances were effective in correcting skeletal Class II malocclusion in growing patients. The TB appliance showed greater efficiency relative to treatment duration, whereas the MA-EPW appliance provided superior lower incisor control and clinically relevant transverse expansion. Further long-term randomised controlled trials with defined and standardised protocols are needed to validate the clinical outcomes of mandibular advancement with clear aligners.

Objective: The premature loss of primary teeth in children may lead to numerous issues, such as decreased arch length/width/perimeter and increased malocclusion, increasing the need for orthodontic treatment. Moreover, a decrease in occlusal forces due to premature, unilateral tooth loss in the upper right quadrant in immature mice (i.e., pre-puberty), may lead to significant bilateral changes in the skull form (i.e., shape and size), especially the mandibular condyles after 3 weeks. In the present study, we aimed to determine the extent of the mandibular and condylar changes after unilateral tooth loss in mature mice (i.e., post-puberty) within the same 3-week time frame.

Materials and methods: We extracted the three maxillary right molars in 8-week-old mice and analysed the skulls after 3 weeks. Eight-week-old mice are sexually and dentally mature, as mice reproduce at 6 weeks of age. We examined the skulls of control (non-extracted) and experimental (extracted) mice using micro-computed tomography (microCT), geometric morphometrics, linear measurements, and histology, focusing on the mandibular condyle and neck.

Results: We performed three pairwise comparisons: non-extracted (left) vs. extracted (right) sides in the same experimental mouse; left side (non-extracted) of experimental mice vs. left side of wildtype mice; and right side (extracted) of experimental mice vs. right side of wildtype mice. We observed no or little change in mandibular and condylar forms in all three pairwise comparisons within the 3-week time frame.

Conclusion: Unlike in immature mice where significant bilateral changes in the shape and size of the mandibular condyles were observed within 3 weeks after tooth loss, we did not observe any significant changes to the mandible and condyles when teeth were extracted in mature mice within the same 3-week time frame. Thus, our current study suggests that whereas normal occlusal forces are essential for the proper growth and development of the mandible and condyles in immature mice, unilateral occlusal changes do not alter the form of the mandible or condyles in mature mice within the same time frame.