Objective : To investigate the effect of incremental saliva contamination mixed directly into the orthodontic primer on the shear bond strength (SBS) of stainless-steel brackets and to analyze the associated failure modes. Methods : A total of 150 freshly extracted bovine mandibular incisors were randomly allocated into five groups (n = 30 per group) based on the volume ratio of artificial saliva to Transbond XT™ Primer (Primer:Saliva, v/v): G0 (100:0, control), G5 (95:5), G10 (90:10), G20 (80:20), and (50:50). Brackets were bonded following standard protocols, including acid etching, primer application, and light curing. After 24 hours water storage and 500 thermocycles (5–55℃), SBS was tested using a universal testing machine. Adhesive Remnant Index (ARI) scores were evaluated under a stereomicroscope. Data were analyzed using one-way ANOVA with Tukey’s HSD post-hoc test and the Kruskal-Wallis H test with Dunn-Bonferroni correction. Results : The Shapiro-Wilk test confirmed normal distribution across all groups, and Levene’s test indicated homogeneity of variances ( P > 0.05). One-way ANOVA revealed significant intergroup differences in SBS ( F = 145.67, P < 0.001). No significant difference was observed between G0 (16.76 ± 1.87 MPa) and G5 (15.53 ± 2.16 MPa) ( P = 0.053). However, SBS decreased significantly in groups with ≥ 10% contamination (G10: 10.24 ± 1.59 MPa, G20: 7.07 ± 1.34 MPa, G50: 4.26 ± 1.42 MPa, all P < 0.001). ARI scores shifted significantly toward lower values with increasing contamination ( H = 63.82, P < 0.0001), indicating a transition from cohesive/adhesive failure to interfacial failure at the enamel-resin junction. Conclusions : Inadvertent mixing of saliva into orthodontic primer significantly compromises bracket bond strength in a dose-dependent manner. While minimal contamination (≤ 5% v/v) may be clinically tolerable, contamination levels of 10% or higher result in a statistically and potentially clinically significant reduction in bond integrity. Clinicians should strictly avoid cross-contamination between the primer brush and saliva, as this form of contamination creates an irreversible weak interface.

This case report illustrates the treatment of a 17-year-old male patient characterized by an anterior open bite, skeletal Class III malocclusion, mandibular deviation, and severe temporomandibular joint symptoms. Given the complexity of the patient's condition, a strategic treatment approach was employed. Stabilization splint was used initially for a duration of 9 months to alleviate TMJ symptoms and repositioning the condyle. Through model analysis on the articulator pretreatment, we found a worsening of his V-shape open bite due to occlusal interference in molars. The patient refused the surgery, so the multiloop edgewise archwire treatment was provided to upright the molars and eliminate occlusal interference. After 26 months of treatment, a functional and aesthetic occlusion, and a relatively well-balanced facial profile were established. After a 6 years post-treatment follow-up, the results of this case have demonstrated long-term stability.

Anterior open bite is a kind of malocclusion that can affect the oral function, aesthetics and even mental health of adolescents. Breaking harmful habits plays an important role in the orthodontic treatment of patients during the growth and development period. This case focuses on a 13-year-old adolescent male with anterior open bite of 6 mm, Class II malocclusion, and finger sucking, tongue thrusting habits, and abnormal swallowing pattern. Based on the etiology and the patient’s condition, a treatment plan involving extraction of second premolars and use of an adhesive tongue crib was implemented. After 35 months of active treatment and 12 months of retention, results showed improved occlusion, normal overbite and overjet, proper molar relationships, and enhanced facial aesthetics. The study highlights addressing etiological factors and using appropriate treatments. A modified Hawley retainer and a retainer with a welded tongue crib at night helped maintain results due to the patient’s history and potential for recurrence. For adolescent patients with anterior open bite, clear diagnosis and elimination of causative factors are key to favorable treatment results. Combining multiple mechanisms can effectively restore and establish a good occlusal relationship. Throughout the treatment, it is also necessary to pay attention to patients’ growth and development. Not applicable.

After bonding brackets to the first deciduous molar in a 2 × 4 technique, a three-dimensional finite element analysis (3D FEA) is used to demonstrate the biomechanical changes in an orthodontic system. This study aims to opt for the appropriate type of orthodontic technology by analyzing and comparing the mechanical systems produced by two types of 2 × 4 techniques employing rocking-chair archwires. Herein, the maxilla and maxillary dentition are modeled by cone beam computed tomography (CBCT) and 3D FEA. Common clinically used 0.016-inch round archwires (material: titanium-molybdenum alloy and stainless-steel) and 0.018-inch round archwires (material: titanium-molybdenum alloy and stainless-steel) are bent into the shape of a rocking chair with a depth of 3 mm. The forces and moments applied to the brackets are transferred to the dentition to evaluate the biomechanical effects of the 2 × 4 technique after the bracket is bonded to the first deciduous molar. For the central incisor, the teeth-moving distance in all three directions increases with bracket bonding to the first deciduous molar applying the 0.016-inch rocking-chair archwire. For the lateral incisor, the tooth root moves toward the gingival side when using 0.016-inch and 0.018-inch archwires. Moreover, for the same archwire size, the lateral incisors move toward the gingival side by bonding the bracket to the first deciduous molar. After bonding a bracket to the first deciduous molar, using rocking-chair archwires of 0.016 inch or 0.018 inch, the buccal movement distance of the first molar crown increases in the X-axis direction. In the Y-axis and Z-axis directions, the modified 2 × 4 technique significantly increases the effect of backward-tipping compared with the traditional 2 × 4 technique. In clinical practice, the modified 2 × 4 technique can be used to increase the movement distance of anterior teeth to a certain extent and accelerate the orthodontic teeth movement. Moreover, the modified 2 × 4 technique is better in anchorage conservation of the first molar than the traditional technique. Although the traditional 2 × 4 technique is widely used in early orthodontic treatment, we found mucosal damage and abnormal archwire deformation might affect orthodontic treatment time and effect. The modified 2 × 4 technique is a novel approach that avoids these drawbacks and improves orthodontic treatment efficiency.

Bone metabolism consists of bone formation and resorption and maintains a dynamic balance in vivo. When bone homeostasis is broken, it can manifest as osteoarthritis (OA), rheumatoid arthritis (RA), osteosarcoma (OS), etc. MiR-671, an important class of non-coding nucleotide sequences in vivo, is regulated by lncRNA and regulates bone metabolism balance by regulating downstream target proteins and activating various signaling pathways. Based on the structure and primary function of miR-671, this paper summarizes the effect and mechanism of miR-671 in bone-related inflammation and cancer diseases, and prospects the application possibility of miR-671, providing reference information for targeted therapy of bone-related disorders.

骨代谢是指骨的转化过程,包括骨形成和骨吸收,临床上骨代谢异常疾病的治疗包括手术治疗和药物治疗等.雷奈酸锶(SrR)是同时具有抗骨吸收和促骨形成双重作用的常用药,主要依靠其中的锶(Sr)元素调节骨代谢.目前,国内外学者对SrR在骨代谢异常中的临床应用研究较多,但对其在调节骨吸收和骨形成作用中的机制研究报道较少,尤其各类信号通路在骨代谢中的调控作用及相关分子表达变化报道较少.现通过各类信号通路及蛋白靶点,主要从SrR对骨代谢影响、作用机制和不良反应等方面进行综述,为SrR的临床应用提供理论依据.

Skeletal Class Ⅲ malocclusion is a commonly encountered clinical malocclusion. It can be into three types based on its pathogenesis: maxillary deficiency, mandibular overdevelopment, or a combination of both. Among these, patients with skeletal Class Ⅲ malocclusion due to maxillary deficiency can benefit from rapid maxillary expansion and maxillary protraction. In recent years, alternate rapid maxillary expansion and constriction has gained widespread acceptance in clinical practice due to its ability to yield more satisfactory correction outcomes. This paper primarily introduces the application, biological basis, and clinical relevance of alternate rapid maxillary expansion.

前牙区是口腔美学治疗的关键,前牙形态和位置的调整是系统性美学治疗的重要部分.临床诊疗中,口腔期望恢复天然牙形态使之与面型协调;关闭前牙间隙、调整中线位置使弓形美观、对称;通过垂直向和水平向控制使牙列与龈、颊组织关系协调,展现美丽微笑.完善的前牙美学治疗需要多学科联合、多种治疗方法介入,同时应考虑患者的文化背景和审美习惯,以实现最佳治疗效果.数字化诊疗技术为治疗前美学分析预测、治疗后美学评估提供了保障.该文结合国内外最新研究成果,从前牙位置、形态以及牙列与龈、颊等软组织关系等方面对口腔治疗中前牙美学考量因素作一综述,为美学区口腔治疗规划提供参考.

上颌快速扩弓技术(rapid maxillary expansion,RME)是正畸学中解决上牙弓狭窄、上颌横向发育不足的常用方法.近年来,随着对RME作用机制的研究逐渐深入,其广泛的生物学效应引起了学界关注.通过调节咽部、鼻腔的生理功能,RME对分泌性中耳炎、鼻阻塞等耳、鼻疾病的治疗有积极作用;通过改善气道及呼吸功能,可减轻阻塞性睡眠呼吸暂停综合征、睡眠磨牙症及儿童夜遗尿等睡眠障碍症状;通过匹配颌骨宽度、改善后牙咬合关系,可缓解部分颞下颌关节疾病的症状.此外,RME对咀嚼肌功能、头颈姿势、发音等生理功能具有潜在影响.利用RME广泛的生物学效应,发挥综合治疗作用,将为多学科疾病的治疗提供帮助.本文将结合国内外最新研究成果对RME治疗在多学科联合诊疗中的作用进行综述,为临床RME的跨学科、综合性应用提供参考.

在正畸固定矫治中,通过改变颌面部硬组织形态、结构和空间位置使软组织产生适应性变化是获得协调和美观面部形貌的主要方式.软、硬组织的改变密切相关,前牙的内收和外展使唇部的凸度、长度、紧张度及颏部的形态发生改变;后牙的近中、远中、伸长和压低移动使下颌骨旋转,从而改变包括鼻、唇部和颏部在内的面下1/3的软组织形态.但颌面软、硬组织的改变并非单一的对应关系,各要素之间相互作用,软组织效应既受其本身长度、厚度和紧张度等特性影响,也受前牙空间位置、牙槽骨及骨面型等个体牙性和骨性特征的影响.此外,矫治过程中个体生长发育对软、硬组织形态产生持续性改变,这将增加治疗结束后患者软组织形貌预测的不确定性.三维面部扫描技术的应用和统计学分析方法的改进使客观、精准的预测成为可能.现结合国内外相关最新研究成果,从牙弓前、后段牙齿的空间位置改变和个体生长发育等角度,对口腔正畸固定矫治过程中硬组织因素对软组织形态的影响进行综述,为临床诊疗制定矫治方案及预测矫治效果提供参考.

With the continuous progress of materials science and biology, the significance of biomaterials with dual characteristics of materials science and biology is keeping on increasing. Nowadays, more and more biomaterials are being used in tissue engineering, pharmaceutical engineering and regenerative medicine. In repairing bone defects caused by trauma, tumor invasion, congenital malformation and other factors, a variety of biomaterials have emerged with different characteristics, such as surface charge, surface wettability, surface composition, immune regulation and so on, leading to significant differences in repair effects. This paper mainly discusses the influence of surface charge of biomaterials on bone formation and the methods of introducing surface charge, aiming to promote bone formation by changing the charge distribution on the surface of the biomaterials to serve the clinical treatment better.