人牙周膜细胞骨保护因子和破骨细胞分化因子蛋白的表达及1α,25(OH)2维生素D3的调节

目的:研究人牙周膜细胞骨保护因子(osteoprotegerin,OPG)和破骨细胞分化因子(receptor activator nuclear factor kappa B ligand,RANKL)蛋白的表达,以及骨吸收促进因子1α,25(OH)2维生素D3对OPG蛋白表达的影响.方法:用系列酶消化法体外培养人牙周膜细胞,用免疫细胞化学检测细胞上表达的RANKL蛋白,以酶联免疫吸附实验检测无外源性刺激以及1α,25(OH)2维生素D3诱导2、4、6 d时细胞分泌到培养基中的OPG蛋白.结果:人牙周膜细胞胞膜和胞浆上表达RANKL蛋白,分泌OPG蛋白到培养基中.1α,25(OH)2维生素D3降低OPG蛋白的分泌.结论:人牙周膜细胞表达OPG和RANKL,1α,25(OH)2维生素D3影响OPG的表达,推测其通过OPG/RANKL通路参与骨改建.这一结论为进一步研究牙周膜细胞参与骨改建的机制打下基础.     

纤维调节素在牙周损伤愈合中的免疫化学定位和表达

目的:研究纤维调节素在牙周组织损伤愈合过程中的免疫化学定位。方法:损伤成年鼠磨牙周围的牙周组织,跟踪28 d,对纤维调节素和Ⅰ型、Ⅲ型胶原在愈合过程中的免疫组织化学分布进行分析。结果:纤维调节素在结缔组织中的免疫组织化学分布与Ⅲ型胶原相似。在牙周损伤愈合早期,纤维调节素分布于损伤区周围的纤维束,特别是损伤的牙槽骨和牙根表面之间的区域,在移行的牙龈上皮细胞中表达明显。愈合中期,纤维调节素广泛表达于肉芽组织成纤维细胞及其基质。愈合晚期,纤维调节素表达于牙骨质和新骨交界处的主纤维。结论:在牙周损伤愈合过程中,纤维调节素可能参与早期胶原纤维生成和对牙骨质和骨的再附着,在组织愈合的早期活动中起重要作用。     

牙槽骨缺损修复对牙齿移动影响的动物实验

目的了解大鼠牙齿在牙槽骨缺损修复区的移动情况。方法选择40只大鼠，造成一侧牙槽骨缺损，填入45％二氧化硅、24．5％氧化钠、24．5％氧化钙和6％五氧化二磷，作为修复侧，另一侧作为对照侧。术后14周用0．39N力牵引双侧第一磨牙近中移动。配对t检验比较牵引8周后双侧磨牙的移动距离和牙周膜宽度。结果36只大鼠两侧第一磨牙的平均移动距离、牙周膜宽度的差异均无统计学意义（P〉0．05）。结论牙槽骨缺损修复侧可以进行正畸牙齿移动，修复侧的牙齿移动距离及牙周组织受正畸力后的改建情况，均与对照侧无显著差别。     

Odontoblasts in developing, mature and ageing rat teeth have multiple phenotypes that variably express all nine voltage-gated sodium channels

Objective

Our goal was to evaluate the expression patterns for voltage gated sodium channels in odontoblasts of developing and mature rat teeth.

Design

We analysed immunoreactivity (IR) of the alpha subunit for all nine voltage gated sodium channels (Nav1.1–1.9) in teeth of immature (4 weeks), young adult (7 weeks), fully mature adult (3 months), and old rats (6–12 months). We were interested in developmental changes, crown/root differences, tetrodotoxin sensitivity or resistance, co-localization with nerve regions, occurrence in periodontium, and coincidence with other expression patterns by odontoblasts such as for transient receptor potential A1 (TRPA1).

Results

We found that Nav1.1–1.9-IR each had unique odontoblast patterns in mature molars that all differed from developmental stages and from incisors. Nav1.4- and Nav1.7-IR were intense in immature odontoblasts, becoming limited to specific zones in adults. Crown odontoblasts lost Nav1.7-IR and gained Nav1.8-IR where dentine became innervated. Odontoblast staining for Nav1.1- and Nav1.5-IR increased in crown with age but decreased in roots. Nav1.9-IR was especially intense in regularly scattered odontoblasts. Two tetrodotoxin-resistant isoforms (Nav1.5, Nav1.8) had strong expression in odontoblasts near dentinal innervation zones. Nav1.6-IR was concentrated at intercusp and cervical odontoblasts in adults as was TRPA1-IR. Nav1.3-IR gradually became intense in all odontoblasts during development except where dentinal innervation was dense.

Conclusions

All nine voltage-gated sodium channels could be expressed by odontoblasts, depending on intradental location and tooth maturity. Our data reveal much greater complexity and niche-specific specialization for odontoblasts than previously demonstrated, with implications for tooth sensitivity.     

三种组织块法培养人牙周膜细胞的比较研究

目的提高人牙周膜细胞(Human periodontal ligament cells,HPDLCs)原代培养的成功率,并缩短培养周期。方法以高血清培养基组织块法、传统组织块法和玻片覆盖组织块法等3种方法原代培养HPDLCs。通过镜下观察细胞形态,免疫组化方法鉴定细胞来源,及绘制细胞生长曲线等方面,对各种方法的成功率进行比较。结果 3种方法所培养的原代细胞均生长良好,呈梭形,波形丝蛋白和碱性磷酸酶染色阳性、角蛋白染色阴性,符合HPDLCs的形态和生物学特征。高血清培养基组织块法的原代培养的成功率为84.21%,明显高于其他2种方法 (P0.01)。结论高血清培养基组织块法能显著提高HPDLCs原代培养的成功率。     

Effect of loaded orthodontic miniscrew implant on compressive stresses in adjacent periodontal ligament

Objectives:To describe the relationship between the proximity of miniscrew implants (MSIs) to the periodontal ligament (PDL) and stress in the PDL under different load magnitudes and different bone properties.Materials and Methods:Sixteen subject-specific finite element models of the region of the maxillary first molar and second premolar were developed using computed tomography images of four patients. For each patient, an MSI surface model derived from micro-computed tomography was placed at four different distances from the premolar PDL. Finite element analysis was conducted with mesial load on the MSI, increasing from 1 N to 4 N. Peak absolute compression stress (CS) was calculated at each 1 N step. Stepwise multiple regression modeling was conducted to explain compressive stress by proximity, load magnitude, and bone properties.Results:The multiple regression model explained 83.47% of the variation of CS and included all three factors: proximity, load magnitude, and bone properties. The model expected significant interaction between the bone properties and load magnitude, implying that strong bone properties could be associated with significant increases in CS at small increases in load.Conclusions:To ensure the safety of adjacent roots, MSIs should be placed at least 1 mm from the roots. Assessment of alveolar bone properties is recommended when the use of MSI is intended, as some patients may present with strong bone properties and thereby a high risk of MSI-induced root resorption.     

20例患者种植体修复1年后周围组织状况观察

目的观察种植修复1年后种植体周围组织状况的变化。方法局部条件较好的20例患者植入26枚种植体,以患者自身的同名健康牙为对照,修复一年后,检测改良菌斑指数、改良龈沟出血指数、探诊深度、边缘骨质吸收状况指标,并进行比较。结果对照组和试验组的各项指标差异无统计学意义。结论在局部条件较好的患者中应用ITl／straumann种植系统可以获得良好的疗效。     

Periodontal changes following distraction osteogenesis in patients with cleft lip and palate: a clinical trial

ObjectivesTo evaluate inflammatory mediator levels and periodontal changes following distraction osteogenesis (DO) in patients with cleft lip and palate (CLP) using mid-maxillary distraction (MMD).Materials and MethodsA total of 20 healthy patients with CLP with Class III malocclusion were included. Segmental forward advancement of the anterior maxilla from the second premolars on both sides using DO was performed. A custom-made, tooth-borne distractor connecting buccal molar segments to the anterior maxilla was used for 7 days with 0.5-mm distraction for the first 2 days and then increased to 1 mm daily until overcorrection. Crevicular interleukin IL-1β and tumor necrosis factor TNF-α levels were measured during distraction. Periodontal clinical parameters and indices were recorded at baseline and 3 and 6 months postoperatively. Soft tissue healing was evaluated histologically at 2 and 4 weeks after distraction.ResultsThe periodontal parameters remained stable during the follow-up periods. Insignificant increases in the level of inflammatory cytokines compared with the control were observed. Histological findings revealed mild inflammatory and structural changes in the gingiva immediately after distraction, whereas regeneration was noticed after 4 weeks.ConclusionsMMD was an effective technique in treating patients with CLP, leading to new bone and soft tissue formation without significant detrimental effect on the periodontium of the adjacent teeth.     

Periodontal and Prosthetic Conditions in Patients Treated with Removable Partial Dentures and Artificial Crowns: A Longitudinal Two-Year Study

In the present longitudinal study the periodontal and prosthetic conditions in 30 patients treated with removable partial dentures and artificial crowns were followed over a period of 2 years. The patients were given individual instructions in oral and denture hygiene and adequate periodontal treatment before the prosthetic therapy was started. The removable partial dentures were carefully planned and designed. The patients were regularly checked, and necessary instructions, scaling and prosthetic corrections were undertaken. The patients cooperated excellently and no significant deterioration was found in the clinical periodontal status of the remaining teeth. Only a few carious lesions were registered. The present study does not support the opinion that a removable partial denture per se will cause periodontal and carious lesions. When teeth with artificial crowns were examined regarding the position of the crown margins it was found that clinically observable gingival inflammations tended to be greatest when the crown margins were subgingivally located. Some deterioration of the removable partial denture occurred during the two-year follow-up concerning preferably occlusion, articulation, stability and clasp retention.     

Epigenetic alterations in aging tooth and the reprogramming potential

Tooth compartments and associated supportive tissues exhibit significant alterations during aging, leading to their impaired functioning. Aging not only affects the structure and function of dental tissue but also reduces its capacity to maintain physiological homeostasis and the healing process. Decreased cementocyte viability; diminished regenerative potential of stem cells residing in the pulp, alveolar bone and periodontal ligament; and impaired osteogenic and odontogenic differentiation capacity of progenitor cells are among the cellular impacts associated with oral aging. Various physiological and pathological phenomena are regulated by the epigenome, and hence, changes in epigenetic markers due to external stimuli have been reported in aging oral tissues and are considered a possible molecular mechanism underlying dental aging. The role of nutri-epigenetics in aging has emerged as an attractive research area. Thus far, various nutrients and bioactive compounds have been identified to have a modulatory effect on the epigenetic machinery, showing a promising response in dental aging. The human microbiota is another key player in aging and can be a target for anti-aging interventions in dental tissue. Considering the reversible characteristics of epigenetic markers and the potential for environmental factors to manipulate the epigenome, to minimize the deteriorative effects of aging, it is important to evaluate the linkage between external stimuli and their effects in terms of age-related epigenetic modifications.