Pattern of distribution of T lymphocytes, Langerhans cells and HLA-DR bearing cells in normal human oral mucosa

The tissue distribution of helper/inducer and suppressor/cytotoxic T cells, Langerhans cells (LC) and HLA-DR bearing cells was determined in normal oral mucosa by use of monoclonal antibodies OKT4, OKT8, OK.T6 and OKIal, respectively. OKT4+ and OKT8+ cells were invariably present in normal oral epithelium and in the lamina propria. OKT8+ cells were consistently seen inside the basal cell layer of the epithelium. The distribution of LC in oral epithelium showed regional variation. In palatal epithelium LC were evenly distributed in the basal half of the epithelium, whereas in buccal mucosa the highest concentration of LC was seen in the epithelium overlying the tips of connective tissue papillae. OKIal stained dendritic cells in the epithelium and plump cells with small dendritic processes in the connective tissue. Some of the latter were located close to the basal cells of the epithelium. The consistent relationship between immunocompetent cells and the epithelium of the oral mucosa suggests the presence of a local immunologic defence barrier in the oral mucosa.     

Pattern of distribution of T lymphocytes, Langerhans cells and HLA-DR bearing cells in normal human oral mucosa

The tissue distribution of helper/inducer and suppressor/cytotoxic T cells, Langerhans cells (LC) and HLA-DR bearing cells was determined in normal oral mucosa by use of monoclonal antibodies OKT4, OKT8, OKT6 and OKIa1, respectively. OKT4+ and OKT8+ cells were invariably present in normal oral epithelium and in the lamina propria. OKT8+ cells were consistently seen inside the basal cell layer of the epithelium. The distribution of LC in oral epithelium showed regional variation. In palatal epithelium LC were evenly distributed in the basal half of the epithelium, whereas in buccal mucosa the highest concentration of LC was seen in the epithelium overlying the tips of connective tissue papillae. OKIa1 stained dendritic cells in the epithelium and plump cells with small dendritic processes in the connective tissue. Some of the latter were located close to the basal cells of the epithelium. The consistent relationship between immunocompetent cells and the epithelium of the oral mucosa suggests the presence of a local immunologic defence barrier in the oral mucosa.     

Bond strength of adhesive resin to three nickel-chromium alloys with varying chromium content

This in vitro study evaluated the influence of chromium content on bond strength and durability between nickel-chromium alloys and an adhesive resin that contained 4-methacryloxyethyl trimellitate anhydride. Three nickel-chromium alloys with different chromium content, as well as pure chromium and pure nickel metals, were bonded and tested for shear strength. After repeated thermocycling, shear bond strength decrease was lower in alloys containing high chromium content. Pure chromium metal demonstrated a 15.2% decrease, whereas pure nickel metal demonstrated the greatest (53.7%) decrease. The results suggest that nickel-chromium alloys with higher chromium content are desirable for 4-methacryloxyethyl trimellitate anhydride resin-bonded restorations.     

Regional variation in Langerhans cell distribution and density in normal human oral mucosa determined using monoclonal antibodies against CD1, HLADR, HLADQ and HLADP

The distribution, density and activation of Langerhans cells (LC) has been established in biopsies of normal human buccal mucosa, hard palate, lateral border and dorsum of tongue, floor of mouth and lip taken from sudden death post mortems. LC were identified in cryostat sections with monoclonal antibodies against CD1, HLADR, HLADQ and HLADP using an immunoalkaline phosphatase technique. The use of post mortem material was validated by comparison with biopsies taken from volunteers. LC were predominantly situated in the basal and immediately suprabasal layers of the epithelium. In floor of mouth, lip, lateral border and dorsum of tongue the cells were found along the length of the epithelium. In buccal mucosa, although LC showed fundamentally a similar distribution, a tendency to cluster around the connective tissue papillae was also noted. In hard palate LC were found parallel to the surface in the mid zone of the epithelium. No evidence of LC free areas was found. Dorsum of tongue had the highest density of LC per mm epithelial surface length (28.3 cells per mm) which was significantly greater (P less than 0.05) than buccal mucosa (25.2) which in turn had significantly more cells (P less than 0.05) than lip (22.4). The lowest density of LC was found in lateral border of tongue (17.6), hard palate (17.6) and floor of mouth (16.7). These sites had significantly fewer cells than lip, buccal mucosa and dorsum of tongue (P less than 0.05). Class II MHC molecules are necessary for antigen presentation and in all sites except buccal mucosa there was no significant difference between the number of cells expressing CD1, HLADR, HLADQ and HLADP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Quantification and distribution of lymphocyte subsets and Langerhans cells in normal human oral mucosa and skin

Normal human oral (check) mucosa was studied to discover whether the oral cavity resembles the Mucosal Immune System (MIS) or the Skin Immune System (SIS). Immunophenotypes of lymphocyte subsets and Langerhans cells (LC) with their exact locations in the epithelium and papillary layer of the normal buccal mucosa were determined and compared with data of normal human skin. In a double staining procedure, the distribution of T-lymphocytes in relation to blood and lymph vessels was determined. Immunophenotyping of LC was done with a CD1a monoclonal antibody. In contrast to the skin, T-lymphocytes in buccal mucosa are not primarily perivascular in location. They are more or less randomly distributed on both sides of the basement membrane. The epithelium of the buccal mucosa contains about 37 times as many T-lymphocytes as the epidermis of normal skin. T-cell numbers in the papillary layer are more or less comparable. The CD4/CD8 ratios of about 1/2 in the epithelium of buccal mucosa and 1/4 in the skin indicates preferential presence of the CD8 subset in both sites, but the helper/inducer T-lymphocytes play a much greater role in the epithelium of the buccal mucosa when compared with skin. B-lymphocytes were not found in the epithelium and papillary layer of the buccal mucosa. Thus, immune response associated cells in buccal mucosa do not show the MIS pattern since B cells are absent. It has more in common with SIS but differences are also apparent. In the epithelium of the buccal mucosa the density of LC does not differ significantly from that of the skin, but the papillary layer of the buccal mucosa contains significantly fewer LC than the skin. As in the skin most of the LC of the buccal mucosa are found in the epithelium.     

镍铬合金烤瓷修复体拆除前后患者尿镍铬含量的检测与评估

目的探讨镍铬合金烤瓷修复体是否会对人体尿液中的镍、铬含量造成影响。方法选择要求拆除原镍铬烤瓷修复体的患者86例,于修复体拆前、拆后1个月,分别检测患者尿镍、铬含量,并按年龄、性别、修复体数目、修复体戴入时间以及修复体有无金属暴露等进行分组分析。结果 86例患者在镍铬烤瓷修复体拆除前后的尿镍含量分别为(3.52±3.05)μg/L、(3.31±3.28)μg/L,差异无统计学意义(P>0.05);拆除前后的尿铬含量分别为(0.81±0.54)μg/L、(1.34±1.15)μg/L,差异亦无统计学意义(P>0.05)。患者的尿镍、铬含量与年龄、性别、修复体的数量、修复时间以及有无金属暴露等均无明显的相关性(P>0.05)。结论镍铬合金烤瓷修复体所释放的镍、铬离子量微小,短期内不足以对人体尿液中的镍、铬含量造成影响。     

Systemic effects of nickel-containing dental alloys: analysis of nickel levels in serum, liver, kidney, and oral mucosa of guinea pigs.

For economic reasons, nickel alloys are in widespread use in dentistry. However, allergic reactions have been observed in nickel-sensitive patients. In this study, absorption of nickel in the serum, liver, kidney and oral mucosa of guinea pigs was examined. Guinea pigs experimentally sensitized to nickel showed significantly higher level of nickel in serum than did control animals. Levels of nickel in experimental and control animals were found to increase over time.     

Long junctional epithelium: epithelial reattachment in the rat.

The mesial gingiva of mandibular first molars of Sprague-Dawley rats were subject to irritants for 1, 2 or 3 months. The irritants were then removed for periods of 2 to 4 weeks before sacrifice (healing phase). The keratinized sulcular epithelium tended to remain stable while the junctional epithelium became very reactive demonstrating three responses: (1) Proliferation occlusally, (2) Proliferation apically and (3) Proliferation into the inflamed connective tissue. In approximately half of the rats the depth of the cuff epithelium did not change during the experimental procedures demonstrating the resistence of the rat to local irritation. In approximately 25 % of the animals (Group A) deepened sulci occurred with subepithelial connective tissue inflammation. In the remaining 25 % of the rats (Group B), the cuff epithelium proliferated apically but an increase in epithelial reattachment occurred (38 %) reducing the sulci to normal depths with reduced subepithelial areas of inflammation. Within the limitations of these results, this model system can be used to study the dynamics of the long epithelial attachment.     

Reduced numbers of Langerhans cells and increased HLA-DR expression in keratinocytes in the oral gingival epithelium of HIV-infected patients with periodontitis

BACKGROUND: HIV-seropositive (HIV+) patients become increasingly susceptible to periodontal diseases as HIV infection proceeds. We have previously shown that HIV+ patients with chronic marginal periodontitis (CMP) have remarkably increased numbers of gingival plasma cells in the connective tissue underlying the oral gingival epithelium, but depressed specific serum IgG levels towards periodontopathogenic bacteria. Langerhans cells (LC) and keratinocytes (KC) are antigen-presenting cells that are important in promoting immune responses. METHOD: In this study we examined, by means of immunofluorescence, the distribution and numbers of LC and activated KC in biopsies taken from inflamed periodontal sites in HIV+ and HIV patients with CMP. RESULTS: In the pocket epithelium in both patient groups, basal layer KC expressed HLA-DR molecules. In the oral gingival epithelium of HIV+ patients, basal layer KC also expressed HLA-DR molecules and numbers of LC were decreased as compared with HIV persons. CONCLUSION: The findings suggest that the oral gingiva in HIV+ patients may be affected by inflammation.     

Do Langerhans cells behave similarly in elderly and younger patients with chronic periodontitis?

OBJECTIVE: The purpose of this study was to compare the number, the distribution and the expression of markers of maturation of Langerhans cells (LC) in elderly and younger patients with chronic periodontitis in order to evidence the effect of aging on LC in inflammatory gingival tissue. METHODS: Gingival tissue specimens presenting chronic periodontitis from 8 elderly patients aged >75 (group E) and from 8 younger patients aged 50-60 (considered as controls, group C) were used for immunohistochemistry with monoclonal antibodies against CD45RB (leucocytes), CD1a (LC), markers of LC maturation (DC-LAMP, CD83) and number of immunolabelled cell subsets was evaluated using image analysis. RESULTS: The difference in the number of CD45RB+ leucocytes in the upper connective tissue between groups was not significant. In group E, the number of CD1a+ LC was significantly decreased (P<0.002) in the epithelium and significantly increased (P<0.0004) in the upper connective tissue. Furthermore, in group E, intraepithelial CD1a+ LC are more often observed in the upper epithelium and their dendritic processes were shorter and less numerous. Concerning the expression of markers of maturation, the numbers of intraepithelial DC-LAMP+ cells and CD83+ cells were significantly increased (P<0.0007 and P<0.02, respectively) in group E. CONCLUSION: During chronic periodontitis in elderly patients, the decrease in the number of intraepithelial LC and the alteration of dendritic processes could be balanced by a cellular distribution often observed in the upper epithelium associated with changes in cell maturation in response to bacterial elements.     

Increased density of lymphocytes bearing gamma/delta T-cell receptors in recurrent aphthous ulceration (RAU)

Lymphocytes bearing the T-cell receptor (TCR) gamma/delta are increased in the peripheral blood of patients with recurrent aphthous ulcers (RAU) and Behcet's disease. In this study, we examined whether the density of TCR-gamma/delta bearing lymphocytes was also increased locally in RAU lesions. Ten RAU lesions from ten patients were compared with ulcer-free mucosa from sites contralateral to the lesions, and with 10 samples of clinically healthy oral mucosa taken from 10 healthy volunteers. Samples were labeled with a panel of monoclonal antibodies specific to CD3, alpha/beta TCR and gamma/delta TCR in avidin-biotin-peroxidase complex (ABC) staining. Lymphocytes expressing gamma/delta TCRs were very low in non-lesional mucosa and clinically healthy mucosa. By contrast, gamma/delta T-cells were numerous and observed in all RAU lesions especially within the epithelium, inflammatory infiltrates and at perivascular locations. The count of gamma/delta T-cells was high in connective tissue of RAU (200 +/- 126 cells/mm2) compared with connective tissue of controls (4+/-4 cells/mm2; P<0.0001) or non-lesional mucosa (5+/-7 cells/mm2). Interestingly, the density of gamma/delta T-cells was also high in the epithelium of RAU (70+/-34 cells/mm2) compared with the epithelium of non-lesional mucosa (2.8+/-06 cells/mm2; P<0.0001) or epithelium of healthy controls (1.2+/-1.5 cells/mm2; P<0.0001). Moreover, the mean percentage of gamma/delta+ T-cells among total CD3+ lymphocytes was increased in the connective tissue area from 4% and 5% in controls and non-lesional mucosa, respectively, to 19% in RAU. In epithelial areas, the average percentage was increased from 2% and 6% in controls and non-lesional mucosa, respectively, to 36% in RAU. These data showed that gamma/delta T-cells are more numerous in RAU lesions and such an increase was purely restricted to RAU inflammatory areas.     

牙菌斑和胃幽门螺杆菌感染联合治疗对复发性口腔溃疡疗效的影响

目的：探讨对牙菌斑和胃幽门螺杆菌（helicobacter pylori,Hp)感染联合治疗对复发性口腔溃疡（recurrent oral ulcer,ROU)疗效的影响。方法：对198例牙菌斑标本Hp-PCR检测阳性患者进行分组治疗：胃镜检查无胃病的ROU患者（A组）仅接受针对ROU的治疗;伴有胃病的患者随机分成B、C组,B组接受抗Hp治疗,C组在清除牙菌斑的同时接受A、B组的联合治疗。观察根除Hp对口腔溃疡疗效及复发的影响。结果：198例ROU中,130例（65．66％）患有不同类型的慢性胃炎和消化性溃疡（peptic ulcer,PU),对口腔溃疡和胃病的疗效以及Hp的清除效果均以C组最佳（P＜0．05）,C组ROU的复发率明显低于A、B组（P＜0．01）。结论：牙菌斑和胃粘膜联合治疗Hp可以提高ROU的疗效,减少其复发;ROU的发病可能与Hp感染有关。     

3种偶联剂对铸造纯钛与硬质复合树脂结合强度的影响

目的 研究3种偶联剂对铸造纯钛试件与硬质复合树脂结合强度的影响。方法 用牙科铸钛的方法制作40个直径8 mm、高3 mm的圆盘状纯钛试件,与树脂粘接面用碳化硅砂纸在流水下打磨、Al2O3喷砂、4%氢氟酸（HF）酸蚀。试件随机分为4组,每组10个。对照组（A组）、硅烷偶联剂组（B组）、Alloy Primer组（C组）、Metal photo primer组（D组）。然后在试件表面均匀涂布硬质复合树脂,检测其与纯钛试件的剪切强度,并进行统计学分析,同时对断裂面进行扫描电镜（SEM）观察。结果 A、B、C、D组剪切强度分别为（9.773±0.67）、（11.463±0.82）、（14.224±0.75）、（13.157±0.73） MPa。A组与B、C、D组的剪切强度相比差异有统计学意义（P<0.01）,B组与C、D组的剪切强度相比差异有统计学意义（P<0.01）,C组与D组的剪切强度相比差异无统计学意义（P>0.05）。结论 KH-570硅烷偶联剂、Alloy Primer 偶联剂、Metal photo primer偶联剂可以显著提高钛与硬质复合树脂的结合强度,KH-570硅烷偶联剂处理组的结合强度低于Alloy Primer偶联剂组和Metal photo primer偶联剂组。     

Evaluation of biomechanical properties of Expanded-Polytetrafluoroethylene Soft Tissue Patch after dorsal implantation in the rat to mimic TMJ lateral reconstruction

Clinically, Gore-Tex Expanded-Polytetrafluoroethylene (E-PTFE) has been used to reconstruct the lateral temporomandibular joint (TMJ) ligament. The purpose of this study was to assess changes in the biomechanical properties of implanted E-PTFE over time with respect to tissue infiltration. Ninety-six specimens of implants were divided into four groups. Group A was the experimental group. Thirty-six autoclave-sterilized specimens were subcutaneously implanted into the backs of 36 rats. The rats were randomly sacrificed at 2 (n = 12), 7 (n = 12) and 12 (n = 12) weeks. The implants were tested for mechanical properties including maximal stress, strain and Young's modulus of elasticity (E) using the servo-hydraulic material testing system (MTS). Group B was the in vitro control group. Thirty-six specimens were placed in tissue culture media at 37 degrees C for a time period equivalent to the experimental group to simulate the effect of a moist, warm environment on biomechanical properties. Group C was the temperature and pressure control group. Twelve specimens were autoclave-sterilized to determine the changes of tensile strength under high temperature and pressure. Control group D (no treatment) was tested to determine the initial tensile strength. The results showed significantly larger maximal stress as well as an increase in E and smaller maximal strain in experimental group A than in control groups B, C and D. There was no significant difference among control groups B, C and D. Histological examination of implants at 12 weeks demonstrated that 0.2-0.3 mm of 1-mm thick implants were occupied by connective tissue from each side. It may be concluded that E-PTFE implants become stronger and less flexible after implantation in vivo.     

The role of gingival connective tissue in determining epithelial differentiation

Free grafts of connective tissue, without epithelium, were transplanted from either the keratinized gingiva or the non-keratinized alveolar mucosa (controls) into areas of the alveolar mucosa in seven monkeys. The grafts were placed in pouches created in the connective tissue as close as possible to the overlying epithelium. After 3–4 weeks, the transplants were exposed by removal of the overlying tissue in order to allow epithelialization from the surrounding non-keratinized alveolar mucosa. The transplants were examined clinically and histologically at time periods between 1 and 12 months.
The gingival connective tissue grafts became covered with keratinized epithelium displaying the same characteristics as those of normal gingival epithelium. The alveolar mucosa transplants were covered with non-keratinized epithelium. This indicates that gingival connective tissue is capable of inducing the formation of a keratinized gingival epithelium.     

不同桩核金属烤瓷全冠修复后前牙抗剪切力的实验研究

目的 探讨不同桩核系统金属烤瓷全冠修复上颌前牙后修复体抗剪切力的差异.方法 对40颗大小相似的新鲜上颌中切牙行根管充填后截冠,随机分成4组,每组10颗.其中3组分别用纤维增强树脂桩和树脂核、预成钛合金桩和树脂核,铸造镍铬合金桩核修复,桩核与金属烤瓷全冠均用树脂粘接剂粘固;另1组用玻璃离子粘固剂粘固铸造镍铬合金桩核和金属烤瓷全冠作为对照组.经温度循环疲劳实验,用万能力学实验机测试样本牙的抗剪切力,并观测折裂型,进行统计学分析.结果 纤维增强树脂桩组、预成钛合金桩组、铸造桩核组及对照组的抗剪切力分别为(534.4±145.7)N、(499.8±168.9)N、(412.6±99.3)N、(337.4±121.2)N.纤维增强树脂桩组和预成钛合金桩组的抗剪切力大于对照组,差异有统计学意义(P＜0.05);纤维增强树脂桩组中可再修复折裂型样本牙数量多于其他组,差异有统计学意义(P＜0.05).结论 纤维增强树脂桩核金属烤瓷全冠修复有较好的抗剪切力,且折裂型多为可再修复型,修复后残根保存率高.     

Immunohistological and morphometric analysis of intra-epithelial lymphocytes and Langerhans cells in healthy and diseased human gingival tissues

Periodontal diseases are histologically characterized by an infiltration of several inflammatory cell populations into the gingival epithelium and connective tissue, associated with degradation of extracellular matrix components. The purpose of this in situ study was to evaluate the inflammatory state of gingival tissues by the number of intra-epithelial lymphocyte (IEL) subsets and the area fraction (AA%) occupied by collagen fibres in the upper gingival connective tissue, and also to evaluate the number of CD1a+ Langerhans cells (LC) in order to show correlation(s), if any, between these histological findings. The gingival samples were from 10 clinically healthy controls (group C), 8 patients with gingivitis (group G) and 9 with chronic adult periodontitis (group P). A quantitative evaluation of the number of cell populations (CD1a+, CD45RB+, CD3+, CD8+, CD20+, TIA-1+ and GrB+ cells) and the area fraction (AA%) occupied by collagen fibres in the upper gingival connective tissue was made by morphometric and automated image analysis. The results showed that, compared with group C, all IEL subset numbers were significantly increased (p<0.05) in G and P groups, CD20+ excepted. In addition, there was a significant increase in the cytotoxic TIA-1+ IEL number (p<0.05) in group P when compared with group G. The study also showed a significant decrease in the number of CD1a+ LC in groups G and P (p<0.02 and p<0.001, respectively) when compared with group C. No significant difference was found in CD1a+ LC number between groups G and P. The determination of coefficients of correlation (r) with data obtained for each patient showed that in group G, CD1a+ LC number was significantly correlated with CD45RB+ (p<0.05) and CD3+ (p<0.01) IEL numbers whereas during periodontitis, CD1a+ LC number was significantly and inversely correlated with CD20+ (p<0.01), cytotoxic TIA-1+ (p<0.01) and with activated cytotoxic GrB+ (p<0.01) IEL numbers. Moreover, in group P a significant (p<0.05) positive correlation was shown between CD1a+ LC number and the AA% occupied by collagen fibres. This work demonstrates a decrease in CD1a+ LC number according to the severity of the periodontal disease estimated by the number of IEL and by the area fraction occupied by collagen fibres in human gingiva. The decrease of such cells could represent a way to avoid immune overstimulation.     

Lipid pattern and fatty acid composition of human palatal oral epithelium.

The lipid pattern and the fatty acid composition of human oral epithelium were studied qualitatively and quantitatively with the aid of thin-layer chromatography and gas-liquid chromatography. The material studied consisted of scrapings from the mucosa of the hard palate of nine cadavers and of three volunteers. Two methods for collecting the material were used: A) the epithelium was isolated by the removal of subepithelial connective tissue from the connective tissue side and B) the epithelium from the epithelial side was carefully scraped off. The lipid pattern of the epithelium was dominated by cholesterol (25 mol %) and phosphoglycerides (total 45 mol %), while triglycerides and free fatty acids constituted 10-15 mol % each. The fatty acid compostitions of the lipids were remarkably similar to each other, although the specific characteristics of each individual lipid were still noticeable. All lipids showed a large proportion of linoleic acid and a relatively small proportion of other polyunsatured fatty acids. In several respects the lipid pattern and the fatty acid composition of the epithelium were similar to those found in other ectodermal tissues, but they exhibited a number of differences from the corresponding pattern of the mesenchymal connective tissue.     

Effect of snuff and smoking on tenascin expression in oral mucosa

We have shown, by using two monoclonal antibodies (143DB7 and 100EB2), that the expression of the extracellular matrix protein tenascin (Tn) is increased in the connective tissue of biopsies taken from snuff users' and tobacco smokers' oral mucosa. In normal oral mucosa Tn was, seen to underlie the epithelium as a thin delicate band. The most intense increase in Tn reaction was observed in snuff users "mucosa while the immunoreaction in smokers' mucosa was less conspicuous. Often the most prominent Tn reaction took place in association with round ceil inflammatory infiltration, indicating epithelial irritation. Tn has been shown to take part in epithelial-mesenchymal interactions during embryogenesis wound healing and tumorigenesis. Here, a superficial epithelial irritant has been shown to cause conspicuous alterations not only in the epithelial cell layers but also in the underlying connective tissue by increasing its Tn content. As a result of our findings we suggest a further link for Tn in a dynamic epithelial-mesenchymal interplay by virtue of this marked connective tissue reaction in snuff users" and smokers' oral mucosa.     

Oral health, dental treatment, and cardiac valve surgery outcomes

The aim of this study was to determine whether not treating chronic dental infection during the admission for cardiac valve surgery would increase the morbidity and mortality of patients.
Patients were divided into three groups: dentally unhealthy and untreated (Group A), dentally healthy not requiring treatment (Group B), and dentally unhealthy and treated (Group C). Hospital computer records and phone interviews were used to assess morbidity and mortality as assessed through the Social Security Death Index.
Ninety-eight patient charts were reviewed. Patients in Group A (n = 47)were not at a significantly greater risk for developing infective endocarditis (IE) within 6 months of cardiac surgery compared to patients in Groups B (n = 17) and C (n = 34). Also, patients in Group A did not have a significantly higher rate of mortality compared to other groups ( p = .09).
The results suggest that there is no need to treat chronic oral infections in patients with compromised cardiac function within 24 to 48 hours prior to cardiac valve replacement surgery since this will not lower the risk of IE and death following cardiac valve surgery. Multicenter prospective case-controlled studies are needed to address this question definitively.