Gingival crevicular fluid transforming growth factor-beta1 in several forms of periodontal disease

BACKGROUND: Transforming growth factor-beta(1) (TGF-beta(1)) has significant effects on periodontal host response regulation. Limited knowledge on the role of TGF-beta(1) in various periodontal disease types and particularly in advanced periodontitis forms warranted the present study. The aim of the present study was to evaluate the gingival crevicular fluid (GCF) TGF-beta(1) levels in patients with different forms of periodontal disease. METHODS: GCF TGF-beta(1) levels were investigated in 32 chronic periodontitis (CP), 30 generalized aggressive periodontitis (G-AgP), 15 gingivitis patients and 16 periodontally healthy subjects. Periodontal status was evaluated by measuring probing depth, clinical attachment loss, plaque and bleeding on probing. TGF-beta(1) levels were analyzed by enzyme-linked immunosorbent assay. The results were expressed in terms of total amount (pg) and concentration (pg/microl). RESULTS: G-AgP and CP groups had significantly elevated GCF TGF-beta(1) total amount compared to healthy group (p<0.008). Moreover, GCF TGF-beta(1) total amount of G-AgP group was significantly higher than that of gingivitis group (p<0.008). G-AgP and CP groups had similar GCF TGF-beta(1) total amount (p>0.008). Significant correlation was found between GCF TGF-beta(1) total amount and all clinical periodontal parameters (p<0.05). CONCLUSIONS: The results of the present study suggest contribution of TGF-beta(1) to the pathogenesis of advanced chronic and aggressive periodontitis. TGF-beta(1) may thus be one of the components modulating exaggerated host response together with other major mediators of inflammation.     

Effect of composition and complexity of dentin-bonding agents on operator variability--analysis of gap formation using confocal microscopy

The variability of gap formation due to different operators and bonding agents around dentin-bonded composites in cylindrical cavities (internal diameter, 3 mm; depth, 1 mm; n = 210) was evaluated in vitro. Seven dentists evaluated two experimental bonding systems (A & B) and one commercial product (C) by each treating 10 teeth with each system. One of the investigators restored all cavities with composite (Z100, 3M ESPE) and removed excess material to expose the cavity margins. After storage in water for 1 wk, the maximum gap-width was measured using a confocal microscope and statistically analysed. The relative gap-widths (%) for the three bonding systems were not statistically different. Means +/- SD were 0.18 +/- 0.06, 0.19 +/- 0.08, and 0.20 +/- 0.06 for groups A, B, and C, respectively. The variation caused by the operator-material interaction was significant. When the operator's variability (SD) within the different materials was examined, group C displayed a significantly lower variability than the other two. It was concluded that the operator variable is a more important consideration than the material variable. The self-etching system performed better than the more complex A and B systems when variability rather than gap size was considered.     

A系小鼠胚腭突细胞培养及生物学特性的研究

目的:研究A系小鼠胚愕突上皮与间充质细胞在DMEM/F-12培养基中进行原代和传代联合培养及其生物学特性。方法:采用机械分离及胰蛋白酶消化法，简便、准确、快速地获得高成活率的A系小鼠胚愕突细胞，并通过流式细胞仪、相差显微镜、光镜等观察其DNA及蛋白质合成、细胞骨架及其结构。结果:联合培养的A系小鼠胚鳄突细胞中，愕突上皮及间充质细胞均能较好地生长，光镜下观察见上皮型细胞呈多角型，单层铺路石状排列，细胞骨架为栅栏型或巢穴型;间充质细胞呈梭型，单层漩涡状排列，细胞骨架呈梭型、多平行排列的纤维。流式细胞仪检测见细胞DNA及蛋白质含量较丰富，细胞增殖活跃。结论:A系小鼠胚愕突上皮与间充质细胞联合培养模型能较好地保持体内胚愕突的上皮细胞及间充质细胞细胞成分的基本特征。     

30%双氧水浸泡后对牙本质中钙/磷含量的影响

目的针对临床型漂白剂在使用中直接接触牙颈部暴露的牙本质和通过牙釉质渗透到牙本质的特点,观察30%双氧水对牙本质中的Ca/P的影响.方法实验组7颗离体牙浸泡在30%双氧水24小时后,对照组5颗离体牙浸泡在生理盐水中24小时后,两组使用OCPC法对浸泡液中的Ca离子含量进行测定,同时运用Fiske-Subbarow法对浸泡液中的磷酸根含量进行测定.然后两组进行统计学比较分析.结果实验组30%双氧水浸泡液中Ca/P含量明显高于对照组(P<0.01).说明在30%双氧水浸泡过程中发生了明显脱矿现象.结论 30%双氧水对牙本质有脱矿作用,建议在使用临床型漂白治疗后应加以再矿化和防龋措施.     

A new incision design for mandibular symphysis bone-grafting procedures

BACKGROUND: Traditional methods of procuring mandibular symphysis bone grafts may leave soft tissue scarring, and cause paresthesia and lip droop. METHODS: Nineteen patients selected for treatment were given general health, periodontal, and radiographic evaluations. Patients had inadequate bone volume for dental implant placement or required preprosthetic ridge augmentation procedures. Prior to surgery, bone sounding was performed to determine tissue thickness. All patients had a minimum of 4 mm of keratinized gingiva. Under local anesthesia, incisions were initiated within the keratinized gingiva. Full-thickness mucoperiosteal flaps were elevated, and small burs were used to obtain bone blocks from the mandibular symphysis. A bone-scraping device was used to obtain strips of cortical bone. A combination of sling and interrupted sutures was used for wound closure. RESULTS: All patients healed uneventfully without wound dehiscence, paresthesia, or lip droop. Sufficient bone was obtained for ridge or sinus augmentation with eventual implant placement. CONCLUSIONS: A new incision design is presented. This flap design is carried out within keratinized gingiva. Limiting the flap design to keratinized tissue facilitates flap closure and avoids wound dehiscence.     

Possible involvement of extracellular signal-regulated kinases 1/2 in mitogenic response of periodontal ligament cells to enamel matrix derivative

The efficacy of enamel matrix derivative (EMD) as an adjunct to periodontal regenerative therapy has been demonstrated in recent clinical studies, however, little is known about its molecular mechanism (s). We examined the mitogenic response of cultured periodontal ligament (PDL) cells to EMD and characterized associated changes in proliferation-related intracellular signaling molecules, including mitogen-activated protein kinases (MAPK) and Akt kinases/protein kinase B (Akt/PKB) kinases. The DNA synthesis of PDL cells increased following treatment with EMD at concentrations higher than 1 microg ml(-1). This mitogenic response to EMD was associated with the selective activation of extracellular signal-regulated kinase (ERK) 1/2. No other MAPKs, or Akt/PKB kinases, responded to EMD stimulation. The EMD induction of DNA synthesis and activation of ERK 1/2 were diminished by pretreatment with suramin, an inhibitor of receptor tyrosine kinases (RTK). The signaling pathway induced by EMD from RTK to ERK 1/2 was similar to that activated by epidermal growth factor (EGF), although the specific binding of 125I-EGF to PDL cells was not affected by pretreatment or concomitant treatment with EMD. These findings suggest that EMD elicits its mitogenic signal through an EMD-specific RTK towards ERK 1/2.     

新型骨替代材料硅磷酸钙的生物相容性实验研究

目的:评价新型骨替代材料硅磷酸钙的生物相容性,从而为其在骨缺损修复领域中的临床应用提供依据。方法:分别选用含10%、5%硅酸钙的硅磷酸钙,分别进行急性毒性试验、肌肉植入试验。结果:含10%与5%硅酸钙的硅磷酸钙无急性全身毒性,对肌肉组织无刺激,植入肌肉后呈降解趋势。结论:新型骨替代材料硅磷酸钙具有良好的生物相容性。     

CAD／CAM口腔修复技术的研究现状

当今是一个科学与技术飞速发展、日新月异的时代，口腔修复医疗追求的最终目标是：个性化、美观、高效、简便地为患者设计、制作各类修复体。从目前实际情况看，口腔计算机辅助设计／计算机辅助制作（CAD／CAM）技术，在今后各类口腔修复体的设计与制作中必将成为主流技术，并将可能逐步淘汰传统铸造工艺。本文就CAD／CAM技术在口腔修复学中的应用作一综述。     

Osteoclast formation from mouse bone marrow cells on micro/nano-scale patterned surfaces

ObjectivesOsteoclasts can sense the surface topography of materials. However, it is difficult to identify the structural factors that affect osteoclast formation and its function. Furthermore, we hypothesized that the type of osteoclast precursor cells also affects osteoclastogenesis in the materials. In this study, we investigated the effects of defined micro/nanoscale patterns on osteoclastogenesis from bone marrow cells (BMCs).MethodsVarious cyclo-olefin polymer (COP) patterns were prepared using nanoimprinting. The effects of shape, size, and height of the patterns, and the wettability of the patterned surfaces on osteoclastogenesis from BMCs were evaluated in vitro.ResultsOsteoclast formation was promoted on pillars (diameter, 1 μm or 500 nm; height, 500 nm). Notably, osteoclastogenesis from BMCs was better promoted on hydrophobic pillars than on hydrophilic pillars. In contrast, decreased osteoclast formation was observed on the nanopillars (diameter, 100 nm; height, 200 nm).ConclusionsWe demonstrated the promotion of osteoclast formation from BMCs on hydrophobic pillars with diameters of 1 μm and 500 nm. Some cellular behaviors in the patterns were dependent on the type of osteoclast precursor cells. The designed patterns are useful for designing the surface of dental implants or bone replacement materials with a controllable balance between osteoblast and osteoclast activities.     

Bioabsorbable materials for guided bone regeneration prior to implant placement and 7-year follow-up: report of 14 cases

BACKGROUND: The purpose of the present study was to evaluate the efficacy of a guided bone regeneration (GBR) procedure prior to implant placement and the long-term outcome of the inserted implants. METHODS: Prior to dental implant placement, GBR procedure was performed on 14 patients (mean age 48 years) using a synthetic hydroxyapatite (HA) spacer under a collagen membrane. After a mean healing period of 8 months, bone biopsies were obtained during the placement of 14 implants. The specimens were processed for histology without demineralization in order to assess bone quality and quantity of the regenerated bone. RESULTS: Both the bone density and the resorption degree of HA particles were relatively varied between samples. The different phenotypes of osteoclasts and multinucleated giant cells and the individual host response could partially explain the unpredictable results in terms of bone remodeling and biomaterial resorption. However, the presence of HA particles in the regenerated bone had no influence on the osseointegration of implants presenting a success rate of 86% after a 7-year observation period. CONCLUSIONS: These results confirm the possibility of regenerating bone by means of bioabsorbable materials, assuring at the same time the long-term success for implants inserted in regenerated sites.