Molecular cloning and expression vector construction of bovine TRIM28.

The bovine TRIM28 gene was amplified from ovary tissue by using RT-PCR. The TRIM28 gene was inserted into the eukaryotic expression vector pIRES2-EGFP and transfected into bovine fetal fibroblasts by using Lipofectamine 3000. TRIM28 mRNA and protein were detected by fluorescence microscope and western blotting. The results showed that the full length of TRIM28 was cloned and pIRES2-EGFP-TRIM28 was constructed successfully. EGFP expression was observed, and the pIRES2-EGFP-TRIM28 transfected group expressed more TRIM28 protein than that by the pIRES2-EGFP group. The TIMR28 gene has been successfully transferred into bovine fetal fibroblasts.

Plaque pH and microflora of dental plaque on sound and carious root surfaces.

Given the hypothesis that root caries is the result of acid formation by acidogenic micro-organisms, the present study was performed to relate sucrose-induced pH response of dental plaque on root surfaces to the microbial composition of the overlying plaque. Seventeen caries-active elderly Chinese with poor oral hygiene and with both sound and carious root surfaces were examined. Plaque pH was measured before and up to one hour after a controlled sucrose mouthrinse. Plaque samples for microbiologic analyses were collected from 2 sound and 2 or 3 carious pH-measurement sites in each subject. The prevalence of the following micro-organisms was assessed as % of total viable counts on Brucella agar: Prevotella intermedia, Prevotella melaninogenica, Fusobacterium nucleatum, Campylobacter rectus, Capnocytophaga spp., Actinomyces viscosus, Actinomyces naeslundi, Streptococcus spp., S. sanguis, S. mitis, S. mutans, S. sobrinus, Lactobacillus spp., and Candida spp. There was no difference in plaque pH response on sound and carious root surfaces. The plaque pH response was more pronounced in the maxilla than in the mandible for both sound and carious sites. There was no difference in microbial composition of dental plaque on sound and carious root surfaces. The pH response to sucrose was the same regardless of the presence or absence of mutans streptococci. Our results thus do not readily support the traditional concept of caries formation.

Dental caries in adult and elderly Chinese.

This paper reports on a study of dental caries conducted among 1744 urban and rural Chinese (from 20 to 80 years old), who were selected by means of a systematic stratified sampling procedure. The prevalence of one or more decayed or filled teeth ranged from 48 to 90% in urban residents, and from 51 to 97% in rural residents, depending on age. The mean number of decayed or filled teeth ranged from 1.2 (+/- 1.9) among 20-29-year-olds, to 6.2 (+/- 5.5) among 70+-year-olds, and was highest among rural residents. Among 20-29-year-olds, the main components of the DFT were enamel lesions and fillings. Among 30-49-year-olds, the DFT consisted mainly of enamel lesions and filled teeth, as well as teeth with lesions involving the pulpal tissues. In subjects over the age of 50 years, lesions involving pulpal tissues were the predominant type, followed by root-surface lesions. In subjects below the age of 50 years, most of the caries experience derived from coronal surfaces, particularly occlusal surfaces. Root-surface caries was predominantly a feature of persons aged 50 years and above. Despite a large number of surfaces being at risk of root-surface caries, less than 10% of the surfaces were so affected. Although cross-sectional in nature, these data indicate that when the oral hygiene standards are poor, caries lesions continue to develop and progress throughout life. With age, dental caries becomes a substantial oral health problem in this population of adult and elderly Chinese, despite the availability of some dental services.

A 10-year study of the progression of destructive periodontal disease in adult and elderly Chinese.

This study describes the progression of destructive periodontal disease among Chinese aged 20 to 80 with limited access to dental health facilities and minimal traditions for oral hygiene procedures. These individuals were followed for 10 years to determine whether the rates for progression of periodontal disease were markedly different than for populations with more access to oral health care. At baseline, participants had been examined for tooth mobility, plaque, calculus, gingival conditions, attachment levels, and probing depths on 4 sites of each tooth present. These probing depth and attachment level recordings were repeated at follow-up, although third molars were excluded from examination. A total of 398 persons remained dentate at follow-up. The analysis demonstrated that virtually all subjects experienced > or = 2 mm attachment loss over the 10-year period, and frequently in a large proportion of the sites present. Attachment loss > or = 3 mm was also widespread, but the distribution of persons according to the extent of > or = 3 mm attachment loss was positively skewed in all age groups. Positive skewness was even more pronounced when attachment loss of > or = 4 mm was considered. Some types of teeth, such as mandibular incisors and maxillary molars, had higher progression rates than did, for example, maxillary incisors. The mean individual attachment loss rates did not differ significantly between age groups, and were remarkably similar to those reported for populations whose access to and tradition for oral health care is widespread.

Subgingival microbiota in adult Chinese: prevalence and relation to periodontal disease progression.

The "checkerboard" Dna-Dna hybridization technology was used to study the epidemiology of 18 microbial species associated with various states of periodontal health and disease, in a sample of 148 Chinese subjects never exposed to systematic dental therapeutic intervention, aged 30 to 39 and 50 to 59 years. Our aims were to: 1) describe the prevalence of these microorganisms; 2) correlate the microbiological and clinical profiles of the subjects; and 3) examine the association between the microbiological variables and the longitudinal changes of periodontal status that occurred over a preceding 10-year period. A maximum of 14 subgingival samples were obtained from each subject-1,864 in all. The frequency of occurrence of the 18 species examined was high in this Chinese population, on both the subject and the tooth site level. However, all species were not found equally capable of reaching high numbers in the subgingival samples and, as a rule, colonized heavily only limited proportions of tooth sites within each mouth. There was a profound increase of certain species such as Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus in deep pockets or progressing sites. Multivariate techniques using the subgingival profile could effectively discriminate between deep/shallow pockets and progressing/ stable tooth sites. The microbiological variables showed an enhanced discriminating potential when classifications were performed on the individual subject level. Colonization by P. gingivalis, B. forsythus, Campylobacter rectus, and T. denticola at levels exceeding certain thresholds entailed a significantly increased probability (odds ratios > 4) for an individual subject to harbor deep pockets or progressing tooth sites.

Predictors of tooth loss over 10 years in adult and elderly Chinese.

This study describes the incidence of tooth loss over a 10-year period in a population of rural Chinese, initially aged between 20 and 80 years. Among the 587 persons who participated in a baseline examination in 1984, 440 persons were available for a follow-up study in 1994. A total of 31 persons, mainly aged 50+ years at baseline, had become completely edentulous. Between 45% and 96% of the persons lost at least one tooth, and the average number of teeth lost ranged between 1.0 and 7.2. The distribution of the number of teeth lost was skew, indicating that a minor group of subjects had a substantially higher risk of tooth loss than the majority. Logistic regression analysis identified six significant predictors of tooth loss among those who remained dentate: age, a high number of teeth with dentinal caries lesions, a high number of teeth with caries lesions of any type, presence of teeth with attachment loss > or = 7 mm, presence of mobile teeth, and a low percentage of sites with subgingival calculus deposits. At the subject level, caries variables and periodontal disease variables seemed equally important predictors of the incidence of tooth loss over 10 years, but at the tooth level caries was a predominant cause of tooth loss in all age groups.

Predictors of destructive periodontal disease incidence and progression in adult and elderly Chinese.

This study describes some predictors of new and progressing destructive periodontal disease over a 10-year period in rural Chinese. A total of 398 persons aged 20-80 years, who had participated in a baseline survey of tooth mortality, dental caries and periodontal conditions and were still dentate 10 years later, were reexamined for the same parameters as assessed at baseline. Three different threshold values were used to define new and progressing destructive periodontal disease. Irrespective of the threshold used, most persons experienced new disease. Progressing disease was very prevalent when a 2+ mm disease definition was used, but occurred less frequently at the higher threshold levels. The logistic regression models for 2+ and 3+ mm disease were essentially similar, and showed that women, persons with 104 sites or more, and persons with 0-5% sites with 4+ mm attachment levels had a lower risk of disease progression as well as of new disease than did men, persons with few sites and persons with 6% sites or more with attachment levels 4+ mm. The variables sex, number of sites present, percentage of sites with 4+ mm attachment levels, and presence of mobile teeth were predictive for new disease using a 4+ mm definition. Age, percentage of sites with 4+ mm attachment levels and percentage of sites with 4+ mm pockets were predictive for progressing disease using the 4+ mm disease definition.

Tooth mortality and prosthetic treatment patterns in urban and rural Chinese aged 20-80 years.

The study describes tooth mortality levels and pattern of prosthetic treatments in a sample of 1744 Chinese aged 20-80 yr who are residents of Beijing area. Complete edentulousness was rarely seen before the age of 60 yr. Beyond this age up to 26% were edentulous, depending on age and sex. The mean number of teeth present ranged from 10.0 to 29.7 depending on age, sex, and area of residence. Below the age of 60 yr very few persons had experienced extensive loss of teeth but thereafter the number of teeth missing was substantially increased. Prosthetic treatments in the form of partial dentures, crowns, and bridges were frequently observed even in the younger age groups. In all age groups the number of teeth exhibiting caries lesions involving the pulp was much higher than the number of teeth exhibiting extensive mobility. Although many people retain a high number of teeth even late in life our findings indicate a substantial need for, in particular, relief of pain services. Concurrently, emphasis must be placed on preventive programs aiming at interfering with ongoing disease.

A summary of geriatric oral health in China.

Very little has been researched or published about the oral health of the elderly in the People's Republic of China. The following overview of the dental status for this population has been prepared, based on data supplied by Dr. Wen-Min Luan.

Caries prevalence in Africa and the People's Republic of China.

Problems arise when attempting to compare caries data collected in both Africa and the People's Republic of China. These difficulties are not only the result of differences in the criteria used for the diagnosis of caries but are also due to the diversity of cultural and social conditions existing within each of the geographical areas. However, interpreted with caution, the data seem to suggest that caries experience among children is still fairly stable and at a low level, in contrast to the predictions of a decade ago. When comparing data from adult and elderly cohorts, however, caries is seen to be a widespread disease with continuing slow progression throughout life.

[A longitudinal study of tooth exfoliation and dental caries in adults in Gucheng village].

In order to observe the Age-Related changes in dental health conditions, we selected Gucheng village, a rural area of Beijing as a surveillance place for our longitudinal study. 575 persons in different age groups were examined in 1984 and 507 persons were reexamined in 1989. The rate of reexamination was 86.4%. During the 5-year period, 0.3-1.8 teeth were missing in 20-40 years old groups and 2.8-5.5 teeth were missing in 50-70 years old groups. Beyond 60 years old groups more than 43% original remaining teeth were missing or present as residual roots. More than 10% original healthy teeth were decayed and more than 90% original caries teeth became aggravated in elderly group within 5 years. This study indicates that the incidences of tooth mortality and dental caries are much higher in elders than in young adults.

Periodontopathogens in elderly Chinese with different periodontal disease experience.

If an etiological relationship exists between destructive periodontal disease and putative periodontopathogens, they would be expected to have a very low prevalence in periodontally healthy elderly persons. To test this hypothesis, 2 subgroups of elderly, rural Chinese (a periodontally "best" and a "worst" group, each comprising 15 persons) were identified in 1990 from a cohort aged 55-69 years, examined in 1984. Assessment of changes in periodontal status over the 6-year period were possible by comparing detailed clinical recordings performed by the same examinator. Subgingival microbial samples were taken at the mesial aspects of an upper central incisor and a lower canine and examined for the presence of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia group, Prevotella melaninogenica group, Capnocytophaga, Selenomonas, Campylobacter rectus as well as predominant Streptococcus and Actinomyces species. During the 6 years prior to microbiological sampling, persons in the "best" group had lost an average of 1.21 +/- 0.48 mm attachment, while persons in the "worst" group had lost an average of 1.60 +/- 0.94 mm. The latter group had lost 53.3 teeth, predominantly for periodontal reasons, in contrast to 1.8 teeth lost in the "best" group. "Best" persons did not differ from "worst" persons with respect to the occurrence of the putative periopathogens, total viable count, and total streptococcal and Actinomyces recovery. Similarly, sites which had experienced an attachment loss > or = 2 mm during the 6-year period did not differ microbiologically from sites with less attachment loss. It is concluded that subgingival microbial characterization does not allow for a distinction between elderly individuals with markedly different periodontal disease experiences.

Active and inactive root surface caries lesions in a selected group of 60- to 80-year-old Danes.

In 90, 60- to 80-year-old patients with teeth retained in both jaws (mean 20.4 +/- 4.3), a total of 1,092 root surface lesions were recorded. Of these 156 were diagnosed as active caries lesions, whereas 509 were considered inactive, and 427 were filled. About 60% of the elderly had one or more active lesions and 79% had fillings. Seventy percent had more than 8 filled or carious (active or inactive) surfaces. The percentage of carious and filled root surfaces in relation to surfaces at risk demonstrated that the buccal surfaces of lower molars and premolars and upper canines were the most severely affected (RCI = 70%) with fillings predominating on easily accessible surfaces. A constant relationship between active and inactive lesions was found on all other surfaces but third molars and upper incisors. The data suggest that active and inactive root caries lesions must be diagnosed as separate entities if the dynamic nature of root surface caries is to be explored in epidemiological studies and clinical trials.

Profiles of destructive periodontal disease in different populations.

In this study we evaluated the traditional view that the severity of periodontal disease varies between populations in that African and Asian populations are more severely affected than other populations. Our data on periodontal destruction in two random samples of a Kenyan and a Chinese adult population were recalculated to conform with the methods of examination and data presentation utilized in each of 6 other studies of attachment loss levels in different populations. The adult Kenyan and the adult Chinese group, who had very poor oral hygiene conditions and massive gingival inflammation, had attachment loss levels which were quite similar to those in a Japanese population (31), in a Norwegian population (27) and in a New Mexico group of adults (30). Attachment losses were similar in a population of young US adults (26) aged between 35 and 60 years relative to the corresponding Kenyan and Chinese groups while young US citizens had higher and elderly US citizens had lower mean attachment levels than either Kenyans and Chinese. Higher attachment loss levels beyond the age of 27 years were reported for a population of Sri Lankan Tamil tea workers (27) and across all ages in two South Pacific island populations (29). Overall, the analysis indicates that the periodontal attachment loss profiles may differ between populations, but that these differences do not conform with the traditional generalization that African and Asian populations suffer more severe periodontal breakdown than other populations.