[Multivariable analysis of tooth loss in subjects with severe periodontitis over 4-year natural progression].

OBJECTIVE: To evaluate the characteristics of severe periodontitis with various number of tooth loss during 4-year natural progression, and to analyze the factors related to higher rate of tooth loss. METHODS: A total of 217 patients aged 15 to 44 years with severe periodontitis were included, who participated in a 4-year natural progression research. Data obtained from questionnaire survey, clinical examination and radiographic measurement. Tooth loss during 4-year natural progression was evaluated. The baseline periodontal disease related and caries related factors were calculated, including number of teeth with bone loss > 50%, number of missing molars, number of teeth with widened periodontal ligament space (WPDL), number of teeth with periapical lesions and etc. Characteristics of populations with various number of tooth loss and the related factors that affected higher rate of tooth loss were analyzed. RESULTS: In 4 years of natural progression, 103 teeth were lost, and annual tooth loss per person was 0.12±0.38. Nine patients lost 3 or more teeth. Thirty-four patients lost 1 or 2 teeth, and 174 patients were absent of tooth loss. Molars were mostly frequent to lose, and canines presented a minimum loss. The number of teeth with WPDL, with periapical lesions, with intrabony defects, with probing depth (PD)≥7 mm, with PD≥5 mm, with clinical attachment loss≥5 mm, with bone loss > 50% and with bone loss > 65% were positively correlated to number of tooth loss. Results from orderly multivariate Logistic regression showd that the number of teeth with bone loss > 50% OR=1.550), baseline number of molars lost (OR=1.774), number of teeth with WPDL (1 to 2: OR=1.415; ≥3: OR=13.105), number of teeth with periapical lesions (1 to 2: OR=4.393; ≥3: OR=9.526) and number of teeth with caries/residual roots (OR=3.028) were significant risk factors related to higher likelihood of tooth loss and multiple tooth loss. CONCLUSION: In 4 years of natural progression, the number of teeth with bone loss > 50%, baseline number of missing molars, number of teeth with WPDL, baseline number of teeth with periapical lesions and number of teeth with caries/residual roots were significantly related to higher risk of tooth loss and multiple tooth loss among Chinese young and middle-aged patients with severe periodontitis in rural areas.

[A brief history of Beijing Shijitan(Century Altar) Hospital].

Founded in 1914, the Jing-Han Railway Hospital has undergone through four different stages during its 100 years' transition, viz., from 1914 to 1949, from 1949 to 1979, from 1980 to 2003 and from 2004 to the present, with its title changing from Peking-Hankou Railway Hospital, Beijing Health Care Station, Peiping Railway Hospital, Beijing Railway General Hospital and today's Beijing Shijitan Hospital. As a railway hospital, in addition to offering services to Chinese railway health, it has also participated in many public welfare activities, such as major disaster rescues, important domestic medical services, the international medical assistance, hospitals' counterpart support, Lifeline Express and so on.In a sense, the establishment and development of the hospital are connected with Beijing Railway Health Services and is not only closely related with China's railway healthcare, but also to modern social transformation and changes.

A novel semiconductor compatible path for nano-graphene synthesis using CBr4 precursor and Ga catalyst.

We propose a novel semiconductor compatible path for nano-graphene synthesis using precursors containing C-Br bonding and liquid catalyst. The unique combination of CBr4 as precursor and Ga as catalyst leads to efficient C precipitation at a synthesis temperature of 200 °C or lower. The non-wetting nature of liquid Ga on tested substrates limits nano-scale graphene to form on Ga droplets and substrate surfaces at low synthesis temperatures of T ≤ 450 °C and at droplet/substrate interfaces by C diffusion via droplet edges when T ≥ 400 °C. Good quality interface nano-graphene is demonstrated and the quality can be further improved by optimization of synthesis conditions and proper selection of substrate type and orientation. The proposed method provides a scalable and transfer-free route to synthesize graphene/semiconductor heterostructures, graphene quantum dots as well as patterned graphene nano-structures at a medium temperature range of 400-700 °C suitable for most important elementary and compound semiconductors.

Peri-implant conditions and their relationship with periodontal conditions in Chinese patients: a cross-sectional study.

OBJECTIVES: To analyze the relationships between peri-implant conditions and periodontal conditions in Chinese patients with dental implants in place for at least 1 year. MATERIAL AND METHODS: Seventy-six patients (mean age, 41 ± 10 years; range, 21-69 years) who received placement of 120 dental implants (Straumann(®) ), (mean 1.6 implants per subject; range, 1-5 implants per subject) after a mean period of 25 months (range, 12-66 months) responded to recall. Clinical examinations were performed around the implants and natural teeth. Periapical radiographs were taken by the long cone technique for implants, and radiographic bone level (BL) was measured. Comparisons of the peri-implant conditions were performed between the patients with different periodontal conditions by t-test and chi-square test. The relative risk of periodontal condition as a risk factor for peri-implant conditions was analyzed by logistic regression. RESULTS: Subjects who presented with ≥5% sites with probing depth (PD) ≥ 4 mm and ≥30% sites with bleeding on probing (BoP) in the dentition showed significantly poorer peri-implant conditions (58% vs. 18% subjects who had maximum modified gingival index (mGI) 2 or 3, P = 0.003; 94% vs. 62% subjects who had maximum PD ≥ 4 mm, P = 0.008; 100% vs. 79% subjects who had BoP, P = 0.044; mean PD 3.36 ± 0.66 vs. 2.75 ± 0.66 mm, P = 0.002; and sites% with BoP 68 ± 23% vs. 36 ± 31%, P < 0.001), as compared with those who had <5% sites with PD ≥ 4 mm and <30% sites with BoP on the remaining teeth. The relative risk for subjects with the more severe and extensive periodontal conditions compared to those with better periodontal conditions to have PD ≥ 5 mm with BoP at peri-implant sites was 23.3 (P = 0.003, 95% CI, 2.8-192.3. CONCLUSIONS: The peri-implant conditions were significantly related to the periodontal conditions around the remaining natural teeth, which implies that control of periodontal disease is essential for successful implant treatment.

Plasma frequency and dielectric function dependence on doping and temperature for p-type indium phosphide epitaxial films.

The optical properties of p-type InP epitaxial films with different doping concentrations are investigated by infrared absorption measurements accompanied by reflection and transmission spectra taken from 25 to 300 K. A complete dielectric function (DF) model, including intervalence band (IVB) transitions, free-carrier and lattice absorption, is used to determine the optical constants with improved accuracy in the spectral range from 2 to 35 µm. The IVB transitions by free holes among the split-off, light-hole, and heavy-hole bands are studied using the DF model under the parabolic-band approximation. A good understanding of IVB transitions and the absorption coefficient is useful for designing high operating temperature and high detectivity infrared detectors and other optoelectronic devices. In addition, refractive index values reported here are useful for optoelectronic device designing, such as implementing p-InP waveguides in semiconductor quantum cascade lasers. The temperature dependence of hole effective mass and plasma frequency is also reported.

Relationship between vitamin D receptor gene polymorphism and periodontitis.

UNLABELLED: Recent studies have shown that vitamin D receptor (VDR) gene polymorphism had regulatory effects on bone mineral density (BMD) and bone turnover. The VDR gene has also been indicated as a candidate gene for the susceptibility of osteoporosis. However, it is unclear whether VDR genotypes could be associated with alveolar bone loss of patients with periodontitis, or whether vitamin D receptor gene could be a candidate gene for susceptibility to periodontitis. The purpose of this study was to answer these two questions. METHODS: Twenty-four cases of adult periodontitis (AP), 37 cases of early onset periodontitis (EOP) and 39 healthy controls were recruited for the study. Individual samples of venous blood and DNA were obtained from each subject. Genotypes of the TaqI VDR gene were determined by PCR and TaqI restriction endonuclease digestion. RESULTS: One out of 24 AP patients, nine out of 37 EOP patients and two out of 39 healthy controls were detected with Tt genotype, while the rest had the TT genotype. The detected frequency of Tt genotype was significantly higher in EOP patients (24.3%) than in AP patients (4.2%) and healthy controls (5.1%). The frequency of t allele was also significantly higher in EOP patients. There was no statistical difference in the distribution of TaqI VDR genotypes between AP patients and healthy controls. The study suggests that Tt genotype might be a risk indicator for the susceptibility to EOP. Carriage of the allele (t) of the TaqI VDR gene may increase the risk of developing EOP.

Photolysis of pesticides: influence of epicuticular waxes from Persica laevis DC on the photodegradation in the solid phase of aminocarb, methiocarb and fenthion.

Pesticides with N,N-dimethyl and thiomethyl moieties (aminocarb, methiocarb and fenthion) were irradiated under artificial light (lambda > 290 nm) in an amorphous wax phase from Persica laevis DC. The effect of the presence of the wax on the photolysis rate differed in the three pesticides, increasing it in aminocarb, having little effect in methiocarb and slowing it down in fenthion. The presence of the wax affected the qualitative photodegradation behaviour of all the pesticides. The data obtained were compared with those for pirimicarb, which had been studied earlier.

Polymorphonuclear neutrophils and their mediators in gingival tissues from generalized aggressive periodontitis.

BACKGROUND: Impaired polymorphonuclear neutrophil (PMN) functions were generally considered to be related to the onset of generalized aggressive periodontitis (GAgP). However, some research has indicated that the hyperreactivity of PMN seems to be involved in the inflammatory response of GAgP. The present study's main purpose was to provide more evidence about the role of PMN in the pathogenesis of GAgP by surveying PMN infiltration in gingiva and its relationship with the expression of their mediators including intercellular adhesion molecule-1 (ICAM-1), interleukin-8 (IL-8), interleukin-1beta (IL-1beta), and tumor necrosis factor-alpha (TNF-alpha). The inflammatory response in GAgP was also compared with that in adult periodontitis (AP) and periodontally healthy subjects. Since these PMN mediators were reported to be produced mainly by macrophages, the association between the expression of these PMN mediators and the distribution of macrophages was also investigated. METHODS: A total of 25 gingival specimens were obtained from 10 GAgP patients, 10 AP patients, and 5 periodontally healthy subjects. Serial sections were obtained from each specimen, and the following techniques were adopted to investigate the distribution and interrelation of different cells and cytokines. Infiltration of PMN was observed by using hematoxylin and eosin staining. Distribution of the macrophages, identified as CD68+, was shown by using immunohistochemistry. Immunohistochemistry and in situ hybridization were used to detect the expression of ICAM-1, IL-8, IL-1beta, and TNF-alpha in gingival tissues. These techniques were performed in serial sections from each individual specimen. RESULTS: Large numbers of infiltrating PMNs were observed in gingiva from GAgP. In gingiva from both GAgP and AP, the strongest protein and mRNA expression of IL-8, ICAM-1, IL-1beta, and TNF-alpha were located in pocket epithelium and adjacent connective tissue with large numbers of infiltrating PMNs. In tissues without abundant PMN infiltration, the appearance of positive cells expressing IL-8, ICAM-1, IL-1beta, and TNF-alpha was scattered. CD68+ was distributed sparsely in connective tissue and was hardly seen in pocket epithelium with large numbers of PMN infiltration. The degree of leukocyte infiltration and connective tissue destruction in gingiva from GAgP patients was not distinctly different from that in gingiva from AP. The gingival specimens with heavy PMN infiltration from both GAgP and AP patients presented strong expressions of IL-1beta and TNF-alpha; showed more extensive inflammatory cell infiltration; had severe connective tissue destruction; and presented severe elongation and ulceration of pocket epithelium. In gingiva from healthy subjects, inflammation was minor with visually no PMN, CD68+, or the positive cells of IL-8, ICAM-1, IL-1beta and TNF-alpha expression. CONCLUSIONS: Enhanced accumulation of PMN, which is associated with the upregulation of IL-8, ICAM-1, IL-1beta, and TNF-alpha expression, relates to the severity and activity of GAgP. In addition to macrophages, PMN and/or epithelial cells might also be important sources of IL-8, IL-1beta, and TNF-alpha production in gingiva.

Phenolic compounds in virgin olive oil. 2. Reappraisal of the extraction, HPLC separation, and quantification procedures.

The extraction procedures (solid/liquid SPE and liquid/liquid LLE) and HPLC separation and quantification methods of polyphenolic compounds have been checked in virgin olive oils in order to explain the differences in content reported in the literature. The work has been carried out on oils prepared from one cultivar and produced under the same protocol. The extraction methods are practically equivalent, but the SPE technique is more favorable because it is faster and simpler. It has been proved that the chromatographic features and the method of chemical expression of the concentrations may greatly affect the final values. Thus, under the same analytical method, the total concentration values of polyphenols of the same oil show variations from 18% to 80%, according to the formality of expression as gallic acid, caffeic acid, or tyrosol equivalents. The role of the nature and spectrophotometric features of the phenols and of the internal standard is also discussed, and it was found to be an important source of reported variation. A gradient separation with an eluent mixture acetonitrile-sulfuric acid (0.1 mol/L), detection at 225 nm, and quantitative calculation of polyphenolic compounds in oils (expressed as tyrosol equivalents, THY(eq)) is proposed.

Attachment loss in rural Chinese children over a 3-year period.

OBJECTIVES: The periodontal condition of 84 children (9-14 years old, 38 males and 46 females) in a rural area of China was monitored over a 3-year period in order to determine the clinical parameters that act as risk factors for attachment loss. METHODS: Plaque and calculus accumulation (PSS and CI), modified gingival index (MGI), pocket depth (PD) and attachment level (AL) of two quadrants of each child were examined in 1993 and 1996. Following calculation of the mean of each of these parameters and statistical analysis of the change in each of the clinical parameters over the 3-year period, the relationship between attachment loss and clinical parameters was analyzed using multiple regression analysis. RESULTS: At the beginning of this study, the mean values for males and females were 3.66 and 3.58 for PSS, 1.22 and 1.17 for MGI, 1.07 and 0.90 for CI, 2.21 and 2.22 for PD, and both 0.02 for AL respectively. No significant difference between males and females was observed. After 3 years, all except mean PSS had increased significantly. Multiple regression analysis indicated that AL correlated only to age (P<0.01). In 1993, although the AL was > or =1 mm for at least one site in 21 children, none had an AL> or =3 mm. In 1996, the number of children with an AL> or =1 mm had increased to 63, and nine of these children exhibited 3 mm AL (one to six sites per child). No other significant differences were observed between the clinical data of these nine children and those of the other children. CONCLUSION: Although attachment loss tended to increase with age, no clinical parameters correlated with attachment loss in children.

Detection of small lesions in alveolar bone by digital subtraction radiography.

OBJECTIVE: To evaluate the effectiveness of digital subtraction radiography (DSR) system for diagnosis of small artificial alveolar bone lesions. METHODS: Seventy-two 0.2-0.9 mm3 lesions were produced in premolar and molar areas of dry human mandibles. Reference and subsequent radiographs were taken before and after lesions were made. The small lesions were detected by conventional radiography and DSR respectively. RESULTS: For 0.2-0.5 mm3 lesions, detection by both DSR and conventional methods was less than 50%. For 0.7 mm3 lesions, the detection by DSR and conventional methods was 57.5% and 38.7%, respectively (P < 0.01). For 0.9 mm3 lesions, the accuracy of the detection by DSR and conventional methods was 89.3% and 57.3% (P < 0.01). CONCLUSION: The detectability of small alveolar bone lesions by DSR was superior to that of the conventional method.

Herbal medicine for periodontal diseases.

Traditional Chinese Medicine (TCM) is a treasure-house which has shown miraculous clinical effects. It has aroused tremendous interests in elucidating its mechanisms both in China and abroad. This paper presents a review of published articles on the effects and mechanisms of herbal medicine on periodontal disease. Specifically, two modifications of an ancient compound prescription were serially studied, Guchiwan (Tooth-firming pills) and Guchigao (Tooth-firming extract). Some in vitro studies have shown suppressive effects of various herbal extracts on bone resorption by isolated osteoclasts. TCM should be intensively studied for their possible use in periodontics.

Genetic analysis of dental traits in 82 pairs of female-female twins.

OBJECTIVE: To study systematically the heritability of dental traits. METHODS: Eighty-two pairs of female-female twins from 6 to 12 years old were collected. Twin zygosity diagnosis was made by DNA fingerprinting. The study was composed of questionnaires, oral examinations, model measurements, and panoramic radiographs. The same analytic method was used for each of the dental traits and comparison of their heritability was made. RESULTS AND CONCLUSIONS: According to the significance of difference and the level of heritability, the dental traits were divided into four types: strong, median, weak, and weaker heritability. The number of third molars present, tooth size, arch size, and upper lateral incisor malformation were under strong genetic influence; hypodontia indicated a median heritability; a weak heritability was seen in tooth eruption and caries, and a weaker heritability was found in occlusal traits. The division made it easy to learn the genetic characteristics of dental traits systematically and supplemented the theory of dental genetics.

Existence of IL-8 degrading protease and anti-IL-8 immunoglobulin G in gingival crevicular fluid.

OBJECTIVE: The aim of this study is to identify the nature of the IL-8 inhibitor(s) in gingival crevicular fluid (GCF). METHODS: Part 1: Fourteen GCF samples were collected from 13 adult periodontitis (AP) patients, and 9 samples were taken from 8 healthy subjects. Each GCF sample was divided into two aliquots. A serine protease-specific inhibitor, PMSF, was added to one aliquot, and PBS was added to the other aliquot as control. ELISA was used to measure IL-8 level in the samples. Part 2: Forty-one GCF samples were collected from 15 AP patients and indirect ELISA was performed to detect the anti-IL-8 IgG antibody. RESULTS: Part 1: IL-8 level in the PMSF samples was significantly greater than that in the control group (3.01 +/- 5.79 mg/L vs 0.05 +/- 0.15 mg/L, respectively P < .001). Part 2: The mean value of anti-IL-8 IgG in GCF was greater than that of negative control + 3 x SD. CONCLUSIONS: A serine protease that can "cleave" IL-8 exists in GCF. Gingival crevicular fluid from AP sites contains an autoantibody against IL-8.

[Pulsed ND:YAG laser irradiation and 2% NaF treatment in caries-like lesion formation in enamel:an in vitro study]

The purpose of this in vitro study was to determine the combined effects of ND:YAG laser irradiation and 2% NaF on caries-like lesion formation in human enamel.There were four groups:(1)control;(2)Nd:YAG laser only;(3)2%NaF only;(4)Nd:YAG laser before 2% NaF.The result show the lesion body depths were significant differences between the control group and all treatment group,and between Nd:YAG laser before 2% NaF group and both Nd:YAG laser group and 2% NaF group(P<0.05).The surface zone depths between Nd:YAG laser before 2% NaF group and both 2% NaF group and both 2% NaF group and control group were also significantly different(P<0.05).

[Longitudinal study on periodontal disease activity in treated periodontitis patients].

The aim of this study was to estimate the incidence of periodontal disease activity (PDA) in treated periodontitis patients in a longitudinal survey. Seven periodontitis patients with 170 teeth (970 sites) participated in this 6 to 12 month study. After initial therapy, the clinical parameters including attachment level (AL) were recorded as the baseline data and then repeated every two months. Occlusal stents were used for each patient to assure the accuracy and reproductivity of the attachment level measurements. Detection of > or = 2 mm of new AL between two consecutive visits was required to designate a site as PDA. During the study period, 21 sites out of 970 sites showed PDA. For better accuracy, we calculated the yearly PDA rate based on the 6-month data because not all the seven patients finished the 12-month observation. The estimated PDA rate per year was 2.8%. Data also showed that maxillary bicuspids and molars on both jaws were more susceptible to PDA. Interproximal sites and sites with > or = 6 mm pockets before treatment showed significantly greater PDA rate than buccal (lingual) sites and sites with < or = 4 mm initial pocket depth. Our data supports the tooth specific and site specific concept in periodontal disease.

[Evaluation of relation between signs of trauma from occlusion and severity of periodontitis].

The aim of the present study was to evaluate the various occlusal interferences, signs of trauma from occlusion and their relations to severity of periodontitis. 32 cases of moderate to advanced adult periodontitis patients participated in the study with a mean age of 37.6 years. All subjects received a complete periodontal examination and occlusal analysis. The results indicated that teeth with various occlusal interferences did not exhibit any greater severity of periodontitis than those without interferences. However, widened periodontal ligament space (PDLS) was frequently seen in teeth with occlusal interference. Two combined criteria were initially suggested to identify the occlusal trauma in clinic. The first criterion included presence of functional tooth mobility plus radiographically widened PDLS. The second, presence of significant tooth wear plus radiographically thickened lamina dura. The results showed that teeth with the first criteria had deeper probing depth, more clinical attachment loss and less alveolar bone support than teeth without these findings. However, teeth with the second criteria had less attachment loss and more bone support than teeth from control group. It was suggested that both of the combined criteria provide better reliability in determination of established occlusal trauma as well as evaluation of adaptive capacity of periodontal structure to increased biting force. The regression analysis demonstrated that given equal clinical attachment levels and similar inflammation, teeth with evidences of functional mobility and widened PDLS had less osseous support than teeth without these findings (P < 0.01). The difference became greater in line with the more loss of clinical attachment.

[Clinical evaluation of manual and ultrasonic subgingival scaling using image analysis]

The objective of this study was to compare the effect of hand and ultrasonic instrumentation in removing subgingival plaque and calculus.In experiment one,forty-eight teeth from patients were randomly assigned to be scaled with curettes or ultrasonic scaler.Probing depth,clinical attachment level and bleeding index were reexamined 2 months latter.The results demonstrated that no significant differences between the two mehtods.In experiment two,seventeen teeth from six patient were also randomly scaled manualty ultrasonic or uninstrumented as a control.All these teeth were extracted immediately after subgingival scaling.The proportion of tooth surfaces covered by residual plaque and calculus(relative to the total surface area of the side of the tooth)was analysed on each tooth using computerized graphic processing.The findings showed the proportional areas of residual plaque and calculus in teeth.But the hand scaled root surface were much smoother than those treated with ultrasonic scaler.

Clinical diagnosis of trauma from occlusion and its relation with severity of periodontitis.

The purpose of the present study was to determine the reliability of several selected signs of trauma from occlusion and their relations with severity of periodontitis. 32 moderate to advanced chronic periodontitis patients participated in the study. All teeth present were evaluated for various abnormal occlusal contacts, signs of trauma from occlusion, and the severity of periodontitis. Standardized periapical radiographs were also taken for each tooth. The results demonstrated that: (1) no significant difference occurred in probing pocket depth (PD), clinical attachment loss (AL), or percentage of alveolar bone height (BH) between teeth with and without various abnormal occlusal contacts, i.e., premature contacts in centric relation occlusion, non-working contacts in lateral excursions, premature contacts of anterior teeth or posterior protrusive tooth contacts; (2) teeth with either significant mobility, functional mobility, or radiographically widened periodontal ligament space (PDLS) had deeper PD, more AL and lower BH than teeth without these signs, while teeth with pronounced wear or radiographically thickened lamina dura had less AL than teeth without these findings; (3) 2 combined indices, i.e., the trauma from occlusion index (TOI) and the adaptability index (AI), were proposed for the identification of occlusal trauma and the response of periodontium to excessive biting forces in heavy function, respectively; TOI-positive teeth exhibit deeper PD, more AL and less osseous support than TOI-negative teeth; however, AI-positive teeth had less AL and more osseous support than AI-negative teeth; (4) with identical attachment level, TOI-positive teeth had less osseous support than TOI-negative teeth while the magnitude of difference became greater with an increase of attachment loss.