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81.
OBJECTIVE: The study was carried out to assess the prevalence of traumatic injuries to the permanent incisors of 14-year-old schoolchildren in Newham in 1998-99, the treatment needed and to compare the results with data from 1995-96. Also, to test whether different levels of deprivation within an area would increase the risk of dental injury. BASIC RESEARCH DESIGN: A cross-sectional study was carried out. One dentist (SM) carried out all dental examinations. Upper and lower permanent incisors were examined for dental injuries. The examiner recorded the type of damage sustained, any treatment carried out and the treatment need. PARTICIPANTS: 411 14-year-old schoolchildren in Newham in 1998-99. Results The prevalence of traumatic injuries was 43.8% (95% CI 39.0, 48.7) in 1998-99, compared to 23.7% (95% CI 22.0, 25.5) in 1995-96. Boys sustained statistically significantly more dental injuries than girls, 50.2% and 37.1% respectively (P<0.01). In 1998-99 92.7 per thousand incisors were damaged, 6.7 per thousand incisors were treated and 28.9 per thousand incisors needed treatment. Two components of the Jarman Index were associated with dental injuries. Overcrowded household was statistically significantly related to dental injuries in both studies. Ethnicity was associated with dental injury in 1998-99, but not tested in 1995-96. CONCLUSIONS The prevalence of traumatic dental injury in Newham increased from 23.7% to 43.8% between 1995-96 and 1998-99, it was higher than the overall prevalence in the United Kingdom (17%) and its treatment had been neglected. Area-based measures of deprivation such as an overcrowded household and ethnicity were predictors of traumatic dental injuries.  相似文献   
82.
BACKGROUND: The present study aimed to explain the interindividual variation in periodontitis susceptibility by differences in the initial adhesion rate of Porphyromonas gingivalis to the pocket epithelium of these individuals, and/or by inter-P. gingivalis strain differences in association capacity (adhesion and internalization). METHODS: Adhesion assays were performed on epithelial monolayers (cultured in vitro from pocket epithelium belonging to patients who were less or more susceptible to chronic adult periodontitis) using 11 genetically different clinical strains of P. gingivalis. RESULTS: Both the disease category (less susceptible versus susceptible) and the interstrain variation were found to have a significant effect (both P <0.05) on the initial bacterial association. The chronic adult periodontitis group showed significantly more association of P. gingivalis when compared to less susceptible patients (4.2 x 10(6) versus 3.5 x 10(6)). Also, the interstrain variation was significant, with strains Pg 4 and 5 representing the least and best associating bacteria (1.8 x 10(6) colony forming units for Pg 4, 9 x 10(6) for Pg 5). CONCLUSIONS: These results indicate that periodontitis susceptibility is influenced by both the interindividual differences in pocket epithelium (allowing more adhesion of P. gingivalis) or by the strain type by which the patient is infected (intra-species differences in adhesion capacity).  相似文献   
83.
Higa K  Gao C  Motokawa W  Abe K 《Oral diseases》2001,7(4):238-245
OBJECTIVES: In order to determine the active sites for salivation of various tachykinins, the regulatory roles of the N-terminal portion of various newly-synthesized tachykinins were studied after i.p. injection of rats using the submandibular glands as model organs. METHODS: N-shortened oligopeptides from kassinin, eledoisin, neurokinins A (NKA) and NKB were synthesized by the multipin peptide synthesis method. Amino acids were eliminated one by one to form octa- to undeca-peptides adjoining the inactive or less active heptapeptides and various heptapeptides, in which an amino acid in position 8 (Xaa8), numbering as in an undecapeptide, was replaced with Tyr, Phe, Ile or Val. RESULTS: The N-terminal amino acids in positions 1 to 4 could be activators or inhibitors, depending on whether the C-terminal heptapeptide was inactive or less active. The Xaa8 residue, in combination with amino acids in positions 5 and 6, seemed to be very important in determining the sialogogic activity of a heptapeptide. The discrimination between NKA and NKB appeared due to the N-terminal amino acid sequence in positions I to 4 including Phe or Ser in position 6. CONCLUSIONS: It is concluded that the N-terminal amino acids in positions I to 4 serve as either activators or inhibitors depending upon the sialogogic activity of the C-terminal heptapeptide, in which particular amino acids in positions 5, 6 and 8 regulate its activity.  相似文献   
84.
OBJECTIVES: To document the incidence of dental anxiety among individuals aged 18 years at baseline and 26 years at follow-up, and to determine if dental treatment experience continues to play a significant etiological role with respect to the onset of dental anxiety in young adults. METHODS: Dental anxiety scale (DAS; Corah, 1969) scores at ages 15, 18 and 26 were obtained for Study members in the Dunedin Multidisciplinary Health and Development Study. Dental examinations were conducted, and sociodemographic and dental service-use data were collected using a self-report questionnaire. Using a case definition of a DAS score of 13 or more, age 18-26 incident cases were identified and their dental treatment experience and service-use characteristics compared with the remainder. RESULTS: DAS scores at 18 and 26 were available for 792 (80.8%) of the 980 26-year-old Study members. An increase in dental anxiety prevalence was observed over the eight-year period, with an annualized incidence of 2.1%. Fewer incident cases had visited a dentist in the previous eight years, and there were no differences between incident cases and others in their eight-year DFS, FS or tooth-loss increments. A subgroup of "recurrent" cases was identified who were dentally anxious at 15 and 26 but not at 18, and their eight-year incidence of tooth loss due to caries was substantially higher than non-cases. CONCLUSIONS: Aversive conditioning experiences appear to be unrelated to the adult onset of dental anxiety, and it may be that particular temperamental or psychological traits are associated with the condition.  相似文献   
85.
Oral asaccharolytic Eubacterium species are associated with periodontal disease and other oral infections. The aim of this study was to use a culture-independent molecular technique to determine the diversity of asaccharolytic Eubacterium species in subgingival plaque in periodontitis. An oligonucleotide PCR primer designed to amplify 16S rRNA genes of the oral asaccharolytic Eubacterium branch of the phylogenetic tree was constructed. This primer was used together with a universal primer in PCRs to amplify gene sequences directly from a single subgingival plaque sample. Fifty PCR products were purified by cloning, fully sequenced and subjected to molecular phylogenetic analysis. The sequences were assigned to four groups within a single lineage of the low G + C gram-positive bacteria. Group I (58% of the cloned sequences) was assigned to a branch that included Eubacterium nodatum, and Group II (22%) to a branch including Eubacterium infirmum. Group III (8%) was distinct from but related to E. infirmum at the species level, and Group IV (12%) was another novel taxon more distantly related to E. infirmum and E. nodatum.  相似文献   
86.
A 3-dimensional bone-implant finite element model was created. The objective was to further investigate the mechanical environment of cortical bone adjacent to the threads of a retromolar endosseous implant used for orthodontic anchorage to mesially translate mandibular molars in response to normal functional loading. This study emphasizes the stress invariants around and between the threads of the implant for future comparison to histomorphometric data from an ongoing clinical study. A strong stress pattern change was found immediately around the implant, which was reflected by a moderate change of stresses between the threads and a significant increase in stress at the tips of the threads.  相似文献   
87.
Li RW 《Dental update》1999,26(7):277-82, 284, 287-7
Enamel hypoplasia is a common condition that may present a severe aesthetic problem. Although the teeth affected may not be particularly susceptible to caries, patients may request cosmetic improvement. Adhesive techniques may be useful in such situations. This paper discusses the management of a patient with enamel hypoplasia using a combination of adhesive systems including enamel- and dentine-bonded veneers, dentine-bonded crowns, a cantilever resin-retained bridge, bonded amalgam restorations and chairside tin plating. Where adhesion was contraindicated, conventionally retained crowns were used.  相似文献   
88.
The distribution of the cell adhesion proteins vitronectin, fibronectin, tenascin, and laminin as well as several integrin subunits, alpha 2, alpha 5, and alpha v, was studied in primate periodontal tissues. Full baboon mandibular sections were analyzed by immunohistochemical methods in order to localize the molecules studied in both soft and hard tissues. Vitronectin was associated with the connective tissue of the marginal gingiva, the periodontal ligament, as well as the endosteum and periosteum. A notable finding was the particularly high staining intensity of vitronectin in the periodontal ligament. Fibronectin was widely distributed in the periodontal connective tissue and was also localized to the pericellular matrix of osteocytes and blood vascular elements. Epithelial basement membranes stained positively for both fibronectin and tenascin. These proteins were also expressed in the periosteal and endosteal connective tissues and the periodontal ligament. The staining intensity for tenascin was higher in zones along the cementum and bone surfaces. Laminin was, characteristically, limited to basement membranes of epithelium and endothelium. The distribution of fibronectin, tenascin, and laminin is related to previous findings in other species. The localization of the several integrin alpha-subunits is also described in full baboon mandibular sections. The vitronectin receptor (alpha v) had a uniquely strong expression in osteoclasts of the alveolar bone and was found, at lesser intensity, on periodontal ligament fibroblasts. The fibronectin receptor alpha subunit, alpha 5, was also observed on osteoclasts, and, in addition, was widely distributed on fibroblasts, cementoblasts, and osteoblasts.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
89.
A case of maxillary ameloblastoma is presented. A non-healing, asymptomatic ulcerative lesion in the maxillary tuberosity region did not respond following relief of physical irritation. The clinical appearance of the lesion was compatible with that of a malignant tumour, but the histopathology was consistent with a diagnosis of ameloblastoma of the maxilla.  相似文献   
90.
Samples of the first molars of offspring whose dams were fed a diet supplemented with caffeine were examined by scanning electron microscopy, X-ray diffractometry and electron microprobe analysis. Scanning microscopy of the enamel surface of the caffeine group revealed a consistently rougher surface than in the non-caffeine controls, both before and after acid exposure. X-ray diffraction analysis of the pulverized whole tooth in the caffeine group showed broader diffraction peaks for the lattice plane reflections (202) and (300), indicating smaller crystallites. Pure enamel samples of the caffeine group examined with a Gandolfi X-ray camera also revealed more diffuse diffraction lines than in the non-caffeine controls, further indicating smaller crystallites in the enamel. The calcium and phosphorus contents of the acid-exposed samples in both control and caffeine groups were lower than the non-acid exposed control and caffeine groups by electron microprobe analysis. After exposure to acid, the calcium and phosphorus contents of the outer surface of the enamel in the caffeine group were greatly reduced as compared to that of the non-caffeine controls. Thus various methods consistently indicate that caffeine ingestion during early growth affects the enamel surface of the first molars, resulting in impaired mineralization. Caffeine intake may therefore have a negative effect on amelogenesis and possibly increases susceptibility to dental caries.  相似文献   
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