Clinical safety of enamel matrix derivative (EMDOGAIN®) in the treatment of periodontal defects

Abstract The aim of the present clinical trial was to test tolerability during 2 treatments with EMDOGAIN® in a large number of patients. An open, controlled study design in 10 Swedish specialist clinics was chosen, with a test group of 107 patients treated with EMDOGAIN® in connection with periodontal surgery at 2 surgical test sites per patient. The procedures were performed 2 to 6 weeks apart on one-rooted teeth with at least 4 mm deep intraosseous lesions. A control group of 33 patients underwent flap surgery without EMDOGAIN® at I comparable site. In total 214 test and 33 control surgeries were performed. Serum samples were obtained from test patients for analysis of total and specific antibody levels. 10 of the patients had samples taken before and after the first surgery. 56 other samples were taken after one treatment with EMDOGAIN®, and 63 after 2 treatments. None of the samples, not even from allergy-prone patients after 2 treatments, indicated deviations from established baseline ranges. This indicates that the immunogenic potential of EMDOGAIN® is extremely low when applied in conjunction with periodontal surgery. Comparison between the test and control groups demonstrated the same type and frequency of post-surgical experiences, i.e., reactions caused by the surgical procedure itself. Clinical probing and radiographic evaluation was performed at baseline and 8 months postsurgery. About half of the patients (44 test and 21 control) were also evaluated after 3 years. There was a significant difference between the test and control results at 8 months post surgery. and this difference had increased further at the 3 year follow-up. The 2.5–3 mm increase in attachment and bone level after treatment with EMDOGAIN® was of the same magnitude as seen in the studies with split-mouth design aiming for lest of effectiveness of EMDOGAIN®.     

Carbohydrate moieties of procine 32 kDa enamelin

The structures of asparagine-linked oligosaccharides of porcine 32 kDa enamelin are reported. The oligosaccharides were released by N-oligosaccharide glycopeptidase digestion, and the reducing ends of the oligosaccharides were derivatized with a fluorescent reagent, 2-aminopyridine. The pyridylamino oligosaccharides were separated into eight kinds of oligosaccharides. The structures of these oligosaccharides were determined by a combination of a sequential exoglycosidase digestion and a two-dimensional suger mapping technique. The oligosaccharides consisted of fucose, galactose, mannose, N-acetylglucosamine, and N-acetylneuraminic acid, and were classified into two groups according to their core-sugar chain structures; one was a biantennary-type and the other was a triantennary-type oligosaccharide. The variation of the oligosaccharides in each of these groups was caused by the differences in the number, the site, and the mode of linkage of N-acetylneuraminic acid to the core-sugar chains.     

釉质发育不全乳牙的超微形态研究

目的：观察不同类型乳牙釉质发育不全的超微表面形态，分析其在分类、致病机制、龋齿易感性中的意义。方法：将发育不全的乳牙固定脱水，临界点干燥，喷金镀膜，日立S－450扫描电子显微镜观察，加速电压20kV。结果：发育不全釉质中存在不同程度形态缺损，病报部位还存在矿化不良。结论：釉质发育不全不仅有釉质量的减少，而且有质的改变，因而可能提高了发育不全釉质对龋齿的易感性。     

大黄提取液对脱矿釉质中钙溶出量的影响

目的 观察大黄提取液对脱矿釉质中钙溶出量的影响.方法 用不同浓度的大黄提取液和去离子水处理牙面后进行脱矿,ASCA生化分析仪对釉质脱矿后的脱矿液进行钙离子浓度的检测.结果 2 mg/ml和4 mg/ml大黄提取液处理后釉质钙溶出量<去离了水(P<0.01)、<1 mg/ml大黄提取液组(P<0.05),>2%氟化钠组但差异无统计学意义(P>0.05).1 mg/ml大黄提取液处理后釉质钙溶出量>2%氟化钠组(P<0.01),<去离子水组但差异无统计学意义(P>0.05).结论 2mg/ ml和4 mg/ml大黄提取液具有抑制脱矿釉质中钙溶出作用:2mg/ml大黄提取液为抑制钙溶出的起始有效浓度.     

Mechanism of toxic action of fluoride in dental fluorosis: whether trimeric G proteins participate in the disturbance of intracellular transport of secretory ameloblast exposed to fluoride

In enamel fluorosis model rats treated with sodium fluoride, secretory ameloblasts of incisor tooth germs exhibited disruption of intracellular trafficking. We examined whether heterotrimeric G proteins participated in the disruption of vesicular trafficking of the secretory ameloblast exposed to fluoride, using immunoblotting and pertussis toxin (IAP)-induced adenosyl diphosphate (ADP)-ribosylation for membrane fractions of the cell. Immunoblotting of crude membranes, post supernatants of the ameloblast, with anti-G_i3/o and anti-G_s antibodies showed that G_i3 or G_o proteins existed in the secretory ameloblast, but G_s protein did not. Immunoblotting of the subcellular membrane fractions indicated that the G_i3 or G_o proteins were located in the Golgi membrane, but were not in the rough endoplasmic reticulum (rER) membrane. Autoradiograph of IAP-induced ADP-ribosylation, however, showed the existence of IAP-sensitive G proteins both in rER and Golgi membranes. Fluoride treatment decreased the G proteins bound to both membranes. These findings indicate that different G proteins, both of which are IAP-sensitive, are present in the rER and Golgi apparatus, and suggest that these G proteins participate in the disturbance of intracellular transport of the secretory ameloblast exposed to fluoride. Received: 24 June 1998 / Accepted: 8 September 1998     

Oral Rehabilitation of a Patient With Amelogenesis Imperfecta

A patient with Type I hypoplastic patterned amelogenesis imperfecta, subtype D, presented for prosthodontic evaluation. This article describes the developmental and pathophysiological background of this disease. A clinical report describing the diagnosis, treatment planning, and dental rehabilitation of the patient is reviewed.     

乳牙釉质表面氟浓度与患龋状况的关系

目的 探讨牙齿不同部位之间、易患龋牙与非易患龋牙之间牙釉质表面氟浓度有无差异。方法 收集上海、北京和深圳3个地区儿童的下颌乳中切牙45颗,并利用微样酸蚀法分析乳牙釉质表面氟元素的分布。结果 氟浓度从釉质表面到内部有由高到低的变化趋势,牙磨耗是牙齿丧失氟的重要元素,未发现釉质表层氟浓度与龋蚀指数(CSI)、龋补牙数(dft)有相关性(P>0.05)。结论 乳牙釉质表面氟浓度与患龋状况无明显相关性。     

Assessment of enamel hypoplasia in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED)

The features of enamel hypoplasia in a small group of patients with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy (APECED) are described. Using a recently developed method, the authors evaluated quantitatively the amount of defect in each tooth by measuring the width of the hypoplastic lesions and dividing the value by the crown height. They then assessed the degree of damage in each tooth type (from central incisors to second premolars) and patient. Canines were the most severely affected among maxillary and mandibular teeth, but all tooth types were involved. Analysing both the differences between patients and their age at the beginning of the defect, the authors observe that hypoparathyroidism is not responsible for the onset of enamel hypoplasia in APECED, although it may contribute to the damage.     

Transmission electron microscopy of early microbial colonization of human enamel and root surfaces in vivo

Abstract – This study describes the early microbial colomization of teeth by the use of light-and transmission electron microscopy. Six dental students carried a total of 60 test pieces of unerupted enamel and root surface in intraoral acrylic appliances for 4, 8, 12, 24 and 48 h, during which periods oral hygiene was abandoned. Pronounced variations were recorded in structure and thickness of the pellicle across the individual surfaces of both dental tissues. Bacterial single-cell colonization increased the electron density of the adjoining pellicle. Micro-colonies of bacteria were observed in relation to enamel surface irregularities such as perikymata, while the distribution on root surfaces appeared incidental. Root surfaces were generally colonized by thicker deposits than homologous enamel surfaces although the structural composition of the microbiota was similar. Gram-positive bacteria with thick cell walls appeared in coccoid or rod-shaped configurations depending on the age of the bacterial deposit. These bacteria were further characterized by selective invasion between collagen fibers. After 48 h the complexity of the microbiota was increased by the establishment of new bacterial species in the superficial layer. It is concluded that the pattern and composition of the early microbiota on teeth is more complex and variable than hitherto assumed.     

Effect of Enamel Prism Decussation and Chemical Composition on the Biomechanical Behavior of Dental Tissue: A Theoretical Approach to Determine the Loading Conditions to Which Modern Human Teeth are Adapted

This theoretical study explored whether the directions of loads to which modern human molars are commonly subjected to are reflected in the biomechanical behavior of the tissue itself. A detailed finite element model of a piece of decussating enamel (M³ paracone) was created, taking into account differences in crystal orientation between the prism head and the interprismatic matrix, and was tested under differently angled mediolateral loads (i.e., mimicking various stages of the chewing cycle). Second, although teeth are highly mineralized, they also contain organic material and water, while in modern humans, there are systematic differences in chemical composition from the outer enamel surface to the dentinoenamel junction. To test the biomechanical effects of this gradient in mineralization a second set of models with gradually changing properties was created and subjected to the same loads. Chemically heterogeneous enamel yielded overall lower stress levels than homogenous enamel, especially at extreme loading angles. However, the general trends regarding the increase in tensile stresses at more oblique angles, and the number of nodes exhibiting tension, were comparable between the different set‐ups. The findings support suggestions that (a) the biomechanical behavior of dental tissue is the combined result of micromorphology and chemical composition and (b) that the range of loading directions, to which teeth are normally subjected to, can be inferred from dental microanatomy. For (palaeo)biological applications, the findings suggest that the absolute strength of teeth (e.g., bite force) cannot be predicted with certainty, whereas kinematic parameters of the masticatory apparatus can. Anat Rec, 2007. © 2008 Wiley‐Liss, Inc.