Binding of Actinobacillus actinomycetemcomitans lipopolysaccharides to Peptostreptococcus micros stimulates tumor necrosis factor α production by macrophage‐like cells

Peptostreptococcus micros is a gram‐positive bacterium that has been associated with periodontitis and endodontic infections. In this study, we hypothesized that P. micros binds the immunomodulating component lipopolysaccharide derived from gram‐negative bacteria to increase its capacity to stimulate cytokine production by host cells. The ability of P. micros to bind Actinobacillus actinomycetemcomitans lipopolysaccharide was demonstrated by an enzyme‐linked immunosorbent assay and by immunoelectron microscopy. Pretreatment of P. micros cells with A. actinomycetemcomitans lipopolysaccharide was associated with a 49‐fold increase in tumor necrosis factor alpha production by human monocytic cells U937 differentiated into adherent macrophages, compared to the stimulation with untreated P. micros. This effect was suppressed by incorporating polymyxin B, a lipid A‐binding substance, during treatment of macrophage‐like cells with lipopolysaccharide‐coated P. micros cells. This is the first study reporting a binding interaction between lipopolysaccharide and a gram‐positive bacterium. This interaction represents a new mechanism that could promote the inflammatory response during periodontitis.     

影响再植牙预后的相关因素分析

目的 分析再植牙根吸收的发生率、发生时间、牙齿在口腔内的保留时间及其影响因素。方法 对1988～2002年在北京大学口腔医院儿童口腔科就诊的59名患儿的68颗延期再植恒牙进行1～15年的临床回顾性分析。结果 再植牙根吸收的发生率为71％；根吸收最常发生在外伤后3～6个月；年龄越大，越早发生根吸收；钙离子导入能延长再植牙在口腔内的保留时间；延期再植牙的脱出时间对其在口腔内的保留时间长短影响较小。结论 延期再植牙经适当的临床治疗，仍可在口腔内保留数年。     

Age as a determinant of severity of dental fluorosis in children residing in areas with 0.5 and 2.5 mg fluoride per liter in drinking water

The purpose of this study was to investigate the influence of age on the severity of dental fluorosis in children exposed to drinking water with either low or high fluoride concentrations. The children selected for this study were aged 10–14 years, with 28 permanent teeth and at least 1 tooth pair with fluorosis. The children were permanent residents of districts in western Uganda with either 0.5 mg (n=33) or 2.5 mg fluoride/l in drinking water (n=186). All vestibular tooth surfaces were examined for fluorosis using the modified Thylstrup and Fejerskov (TF) index. In the high fluoride community, the proportion of teeth per child with TF scores ≥4, and ≥5 was significantly higher among children aged 13–14 years compared to those aged 10–12 years. Children’s chronological age correlated positively and significantly with the median TF scores for all teeth, including early erupting (first molars and incisors) and late erupting teeth (canines, premolars and second molars). In linear regression analyses, the median TF score for all teeth, as well as for early erupting and late erupting teeth, increased significantly with age. On the other hand, in the low fluoride community there was no significant association between age and the severity of fluorosis. This study showed a significant increase in the severity of fluorosis with increasing age in a high fluoride community, whereas no change in severity with age was observed in a low fluoride community. Received: 3 February 2000 / Accepted: 15 March 2000     

Comparison of malignant tumors and sinusitis of maxilla on CT images: Sites of bone destruction

We used CT to examine the bone destruction sites of the entire bone wall of the maxillary sinus in cases of malignant tumors of the maxilla and in maxillary sinusitis cases to investigate the differences between the destructive findings of the bone of both patient groups. The study subjects consisted of 13 patients with malignant tumors of the maxilla and 45 patients with maxillary sinusitis. Destruction of the bone wall was seen in 100% of the patients with malignant tumor of maxilla patients and in 57.8% with the maxillary sinusitis, hence showing a significantly higher incidence in malignant tumors of the maxilla. Neither group of patients exhibited disease-specific characteristics of their bone destruction. The incidence of posterolateral bone destruction in patients with malignant tumor of the maxilla patients was 61.5%, while it was significanty lower at 23.1% in the maxillary sinusitis patients. The number of bone walls affected was 2 or more walls in 84.5% of the malignant tumor patients of the maxilla patients and in 42.3% of the maxillary sinusitis patients.     

牙周炎与肿瘤相关性研究进展

牙周炎是引起成年人牙齿丧失的主要原因，与许多系统性疾病关系密切，如心脑血管疾病、糖尿病、呼吸系统疾病、消化系统疾病等。近年来，有关牙周炎与肿瘤发生发展关系的研究越来越多。文章从口腔癌、消化系统肿瘤、肺癌、乳腺癌4个方面，对牙周炎与某些肿瘤相关性研究进展做一综述，以期为肿瘤患者的预防和治疗提供参考。     

Malignant tumor involving paranasal sinuses

Carcinoma of the paranasal sinuses is a very serious disease, but its incidence is lower than that of any other oral malignancy. Failure to diagnose it early because of misleading symptoms resembling sinusitis usually leads to its detection at a stage when it has already destroyed the bony walls of the sinus and has spread to surrounding structures (infratemporal fossa, posterior ethmoid cells, orbit, cribriform plate, nasopharynx, sphenoid sinus or base of the skull). It is uncommon for this cancer to spread to the regional lymph nodes as long as it remains confined within the maxillary sinus. CT scanning provides an accurate assessment of the extent of resection required and is usually used as an indicator of operability. A 56-year-old man with a chief complaint of palatal swelling, pain and pus discharge was referred to Seoul National University Dental Hospital. Orthopantomogram and Waters' view revealed an aggressive bone destruction in the right maxillary molar area, ipsilateral sinus opacification and destruction of the lateral wall of the maxillary sinus. The CT fidding showed that the right maxillary sinus was occupied by a soft tissue mass which represented a central low density, with an irregular shape at some levels. The tumor mass also involved the pterygopalatine fossa, right esthmoid sinus, nasal cavity and hard palate. Incisional biopsy was done and the biopsy report was squamous cell carcinoma. He was transferred to Internal Medicine for chemotheraphy because of inoperability.     

Eosinophilic granuloma of the ramus similar to malignant neoplasm or osteomyelitis: Report of a case

An eosinophilic granuloma was discovered in the region of the ramus of the mandible. This case occured in a very rare location limited only to the ramus, and showed similar features resembling osteomyelitis or malignant neoplasm at different stages of the disease. The radiographic findings indicated a diagnosis of malignant neoplasm and the scintigraphic manifestations showed that of osteomyelitis. The histopathological examinations showed different manifestations in accordance with the respective stages of the disease. This case was finally diagnosed as eosinophilic granuloma showing rapid regression.     

牙源性角化囊肿上皮细胞增殖动力学初步研究

目的探讨角化囊肿上皮细胞增殖特性,进一步了解角化囊肿的生物学行为,为临床治疗和预防复发提供一定的依据。方法采用增殖细胞核抗原（ｐｒｏｌｉｆｅｒａｔｉｎｇｃｅｌｎｕｃｌｅａｒａｎｔｉｇｅｎ,ＰＣＮＡ）免疫组化法和细胞核ＤＮＡ含量分析,对牙源性角化囊肿、根尖囊肿、含牙囊肿和造釉细胞瘤上皮细胞进行对比研究。结果角化囊肿上皮细胞增殖活跃,与造釉细胞瘤相似。提示角化囊肿生物学特性为上皮细胞主动生长,而非被动性膨胀生长。结论角化囊肿可视为具有侵袭性生长的良性肿瘤,提出命名为“牙源性角化囊性瘤”更能反应其生物学特性     

同源盒基因HOXC 13在成釉细胞瘤中的表达

目的研究HOXC13 mRNA在成釉细胞瘤（ameloblastoma，AB）中的表达，探讨其发生的意义。方法采用原位杂交法检测47例AB（原发AB 29例，复发AB 14例，恶变AB 4例），同时选取骨纤维异样增殖症2例，牙源性角化囊性瘤（keratocystic odontogenic tumor，KCOT）10例，正常口腔黏膜上皮7例作对照。结果HOXC13 mRNA AB中阳性率为97．9％（46／47），10例KCOT中7例为HOXC13 mRNA阳性表达，但在7例正常口腔黏膜细胞中仅3例为HOXC13 mRNA阳性表达，AB、KCOT、正常黏膜三组间差异有统计学意义（χ^2=21．665，P=0．001），但角化及颗粒样变退化细胞却为阴性。在部分AB间质成纤维细胞质中也有阳性表达，2例骨纤维异常增殖症纤维也为阳性。结论在AB中存在HOXC13的高表达；HOXC13 mRNA在AB上皮中的表达有异质性，该基因可促进上皮的增殖，其丢失可导致上皮细胞的角化和退变。     

Long-term results of mandibular reconstruction with autogenous bone grafts and oral implants after tumor resection

Objectives: (a) To evaluate retrospectively the clinical outcome of non‐vascularized bone grafts used for the reconstruction of mandibular defects following tumor resection; (b) to evaluate the clinical outcome of implants and implant‐supported prostheses placed in the reconstructed areas; and (c) to evaluate patients' satisfaction regarding function and esthetics after oral rehabilitation. Material and methods: In a 9‐year period (1995–2003), 29 patients affected by mandibular tumors involving to tooth bearing areas were treated by means of tumor resection and immediate or delayed reconstruction with autogenous non‐revascularized calvarial or iliac bone grafts. Among these patients, 16 patients were selected for dental rehabilitation of the lost dentition with implant‐supported 3fixed prosthese333s. For to 7 months later, the patients received 60 oral implants for the prosthetic rehabilitation of the reconstructed edentulous areas. Results: No total failure of the graft was observed, while partial loss of the graft was observed in one patient. The mean follow‐up of patients after the start of prosthetic loading of implants treated was 94 months (range: 36–132 months). Two patients dropped out of the follow‐up after 3 and 4 years of observation, respectively. Two implants were removed due to loss of osseointegration, while two implants, although still integrated, presented peri‐implant bone resorption values higher than those proposed by Albrektsson et al. for successful implants. Cumulative survival and success rates of implants were 96.7% and 93.3%, respectively. Conclusion: Results from this study demonstrated that bone defects following resection of mandibular tumors can be predictably reconstructed with autogenous bone grafts taken from the calvarium or the anterior iliac crest. It has also been shown that the long‐term survival and success rates of implants placed in the reconstructed areas (96.7% and 93.3%, respectively) may guarantee an excellent prognosis of implant‐supported prostheses.