Biomedical subjects

E F Corbet

Publications and source records attributed to E F Corbet.

At least 19 recordsLinked to original sources

PubMed2006

ART and conventional root restorations in elders after 12 months.

Successful use of atraumatic restorative treatment (ART) in children has been reported, but little information is available regarding its use in older adults. The hypothesis of this study was that survival rates of root restorations placed by both ART and the conventional technique were similar. Root-surface caries lesions in 103 institutionalized elders in Hong Kong were treated randomly by either: (1) the conventional approach-caries removed by dental burs, and the cavity filled with light-cured resin-modified glass ionomer; or (2) the ART approach-caries removed by hand instruments, and the cavity filled with chemically cured high-strength glass ionomer. In total, 84 conventional and 78 ART restorations were placed. After 12 months, 63 conventional and 59 ART restorations were reviewed, and the respective 12-month survival rates were 91.7% and 87.0% (p > 0.05). It is concluded that the survival rates of both types of root restorations were high and similar.

Age Factors↗

PubMed2003

Oral colonisation by aerobic and facultatively anaerobic Gram-negative rods and yeast in Tibetans living in Lhasa.

Sample groups of children (n=50) and adults (n=38) were selected from pools of 207 children, (11-13-year olds from two primary schools) and 94 adults (25-44-year olds from four governmental agencies) who were the subjects of an oral health survey among Tibetans living in Lhasa, Tibet Autonomous Region. Mean ages of the study groups of children (38% females) and adults (61% females) were 11.6+/-0.9 and 37.1+/-6.1 years, respectively. All had lived in Tibet since birth. Oral rinse samples were selective cultured to isolate, quantify and speciate aerobic and facultatively anaerobic Gram-negative rods (using the API 20E kit) and yeasts (using API 20C AUX and API ZYM kits). For children, the isolation rates for oral coliform bacteria and yeasts were 84 and 14%, respectively, for adults, the respective rates were 26 and 40%. The corresponding quantities of coliforms/yeasts for children and adults were 0.4+/-1.6 x 10(3)c.f.u./15.8+/-72.3 and 0.2+/-0.6 x 10(3)c.f.u./57.2+/-137.5c.f.u. per millilitre oral rinse, respectively. Aerobic and facultatively anaerobic Gram-negative rods and Stenotrophomonas maltophilia, a free-living saprophytic and ubiquitous bacterial species of wide geographic distribution, were significantly more frequently recovered from the children's oral rinses. The isolation rates of facultatively anaerobic Gram-negative rods in adults and yeasts in both groups were similar to those found in similar cohorts from southern China in earlier studies. Randomly amplified polymeric DNA analysis showed that the S. maltophilia spp. isolated from children were of several different clonal types and were school specific. This study shows that the colonisation rate of facultatively anaerobic Gram-negative rods in adults and yeasts in both groups are similar to those in populations living at lower altitudes, the native young, urban Tibetans appear to exhibit a high oral carriage rate of S. maltophilia spp.

Adolescent↗

PubMed2003

In vitro calibration and validation of a digital subtraction radiography system using scanned images.

OBJECTIVES: To calibrate and validate a digital subtraction radiography system using scanned images for quantification of alveolar bone changes by means of computer-assisted densitometric image analysis (CADIA) in vitro. MATERIALS AND METHODS: Noise levels were determined using 10 standardized periapical radiographs of the same lower molar region in a human dry skull. For validation of the system, radiographs were taken before and after bovine bone particles in measures with increments of 2 mg weighing from 2 to 20 mg were added into each socket of three dry skulls. Radiographs were developed and scanned into a computer with a flatbed scanner. After digitization, the images were subjected to alignment, normalization and subtraction. Appropriate regions of interest (ROIs) were selected and their CADIA values were calculated for the determination of noise levels, and correlations between the CADIA values and the actual bone mass were performed. RESULTS: When the threshold value was 7, the percentage of pixels deviating from the set threshold value was small (0-11.3%). There were statistically significant correlations between the actual bone mass and the CADIA value for anterior sockets (p<0.001, r2=0.89) and posterior sockets (p<0.001, r2=0.9). For pooled data of both anterior and posterior sockets, the correlation was also statistically significant (p<0.001, r2=0.88). CONCLUSIONS: A high and statistically significant correlation between the actual bone mass and CADIA value was obtained, which suggests that the system could be suitable for the detection of small alveolar bone changes.

Absorptiometry, Photon↗

PubMed2003

Are periodontal diseases risk factors for certain systemic disorders--what matters to medical practitioners?

OBJECTIVE: To review recent data on the nature and pathobiology of periodontal infections and to elaborate how periodontal infections might increase susceptibility to some important systemic diseases and conditions. DATA SOURCES: Medline literature search and websites of the American Academy of Periodontology and American Medical Association. STUDY SELECTION: Literature and data on periodontal diseases and their links to systemic diseases. DATA EXTRACTION: Review of relevant information and data. DATA SYNTHESIS: Periodontal diseases, including gingivitis and periodontitis, are among the most common infections of humans. They are induced by bacteria and bacterial products of dental plaque and are characterised by inflammatory destruction of tooth-supporting connective tissues and alveolar bone. A growing body of scientific evidence has shown that severe periodontitis may enhance susceptibility to certain important systemic diseases and conditions, for example, cardiovascular disease, diabetes mellitus, adverse pregnancy outcomes, and pulmonary infections. The clinical implications of the emerging specialty of periodontal medicine for dental and medical practitioners are postulated. CONCLUSIONS: Periodontal diseases may be risk factors for cardiovascular disease, diabetes mellitus, adverse pregnancy outcomes, and pulmonary infections. Dental and medical practitioners should be aware of the clinical implications of these inter-relationships and treat affected patients in collaboration for better oral and general health.

Cardiovascular Diseases↗

PubMed2003

The effects of tobacco use on oral health.

OBJECTIVE: To review the effects of tobacco use on oral health, with particular emphasis on the effects of periodontal diseases, dental implant failures, and risk of development of oral cancers and precancers. DATA SOURCES: Medline literature search (1977-2002). STUDY SELECTION: Key words for the literature search were 'tobacco smoking', 'periodontal disease', 'dental implant', and 'oral cancers and precancers'. DATA EXTRACTION: Evidence-based literature review. DATA SYNTHESIS: The prevalence and severity of periodontal diseases in their various forms are higher among smokers than among non-smokers. The success of dental implant treatments is significantly influenced by addiction to tobacco smoking. The failure rate of implant osseointegration is considerably higher among smokers, and maintenance of oral hygiene around the implants and risk of peri-implantitis are adversely affected by smoking. The risks of developing oral cancers and precancers are greater in smokers. Betel nut chewing and smokeless tobacco produce similar risk to cancer incidence as tobacco smoking. Cessation of tobacco use has a beneficial effect on halting the progression of periodontal diseases and on the outcome of periodontal therapy. CONCLUSIONS: Medical and dental teams should be aware of oral problems associated with tobacco use. Counselling on smoking cessation and smoking prevention programmes should be an integral component of medical and dental teaching and practice.

Carcinoma, Squamous Cell↗

PubMed2002

Relationship of changes in interleukin-8 levels and granulocyte elastase activity in gingival crevicular fluid to subgingival periodontopathogens following non-surgical periodontal therapy in subjects with chronic periodontitis.

OBJECTIVES: To determine the effect of scaling and root planing (SRP) on the interrelations of subgingival periodontopathogens and both interleukin-8 (IL-8) and granulocyte elastase activity in gingival crevicular fluid (GCF), and to assess their relations to the short-term treatment response in management of chronic periodontitis. MATERIAL AND METHODS: GCF and subgingival plaque were collected from 16 subjects with untreated chronic periodontitis at baseline and 4 weeks after SRP. IL-8 levels were determined by ELISA. Granulocyte elastase activity was analyzed with a specific substrate, pGluProVal-pNA, and the maximal rate of elastase activity (MR-EA) was calculated. 5 DNA-probes were used to detect the presence of A. actinomycetemcomitans (A. a.), B. forsythus (B.f.), P. gingivalis (P.g.), P. intermedia (P.i.), and T. denticola (T.d.), with a sensitivity = 103 cells/paper point. RESULTS: IL-8 and MR-EA levels in GCF decreased significantly after SRP (p < 0.001) with a corresponding reduction of total count of the species. Of the sites with probing depth (PD) >/= 5.0 mm and co-infection by B.f., P.g., P.i. & T.d. at baseline, the sites without persistent co-infection of these species after SRP exhibited a significant reduction of IL-8 levels (p < 0.02), MR-EA levels (p < 0.02) and PD (p < 0.01). No such change was found in the sites where such a co-infection persisted. Moreover, reduction of IL-8 levels in those pocket sites was accompanied by a concomitant reduction of MR-EA (p < 0.02) and PD (p < 0.01), while no significant change in MR-EA levels and PD was noted in those pocket sites that exhibited an increase of IL-8 levels after SRP. At baseline, the former group of sites showed significantly higher IL-8 levels than the latter group of sites (p < 0.02). CONCLUSIONS: IL-8-related granulocyte elastase activity was related to the change in infection patterns of the target periodontopathogens following scaling and root planing. Varying initial IL-8 levels in GCF and a corresponding shifting change of granulocyte elastase activity in GCF may characterize the different short-term treatment responses.

Adult↗

PubMed2001

An Oral Health Survey in Southern China, 1997: background and methodology.

Relatively limited information is available about the oral health in the Guangdong Province of Southern China, the closest neighbor to Hong Kong. The study intended to explore the oral health status, knowledge, attitudes, and dental care utilization in the Guangdong population as a basis for formulating strategies for oral health prevention and treatment. Through multi-stage stratified and quota-sampling, individuals from urban as well as rural communities were selected (5- to 6-; 12-; 35- to 44-; and 65- to 74-year-olds; total N = 6251). Structured interviews and clinical examinations were performed. Inter-examiner reliability was high (kappa = 0.60-0.96). Samples of community water were taken for fluoride assessment. Overall, the sample surveyed was acceptably representative of the population, with some under-representation of rural residents and agricultural workers. Re-weighting was performed in appropriate analyses. The data analysis model used in the Second International Collaborative Study was used as a guide for the present data analysis. This approach has not previously been used on a Mainland Chinese population.

Adolescent↗

PubMed2001

Periodontal conditions in adult Southern Chinese.

Periodontal diseases remain a concern in adult populations, but there have been no systematic descriptions of periodontal conditions, which have included periodontal attachment loss, among Southern Chinese. The main aim of this report is to describe the periodontal conditions in adult Chinese and to investigate factors that may have influenced periodontal attachment loss. Subjects were recruited from urban and rural survey sites throughout Guangdong. In total, 1,572 35- to 44-year-old subjects and 1,286 65- to 74-year-old subjects completed a structured interview and underwent a periodontal examination, which included the Community Periodontal Index (CPI) and periodontal Attachment Loss (ALoss) recordings. Calculus was found as the highest CPI score in 61-68% of the 35- to 44-year-old subjects and in 54-57% of the 65- to 74-year-olds. Shallow pockets were found as the highest CPI score in about one-third of both the urban and the rural subjects in both age groups, and deep pockets in 3-7% of the subjects. ALoss was more prevalent than pockets in both age groups. On the basis of the ALoss recordings, about one-third of the subjects in both age groups were categorized as exhibiting considerable ALoss for their age. In both age groups, logistic regression analysis indicated that being male, wearing partial dentures, and reporting less frequent toothbrushing were found to be associated with considerable ALoss.

Adult↗

PubMed2001

Oral mucosal lesions in adult Chinese.

The objectives of this analysis were to determine the prevalence of oral mucosal lesions (OML) among adults in Southern China and to determine possible associations between OML and reported tobacco-smoking and alcohol-drinking habits. The sample consisted of 1,573 35- to 44-year-old and 1,515 65- to 74-year-old Chinese from both urban and rural areas of Guangdong Province. The subjects were interviewed by trained interviewers and underwent a clinical examination of the oral mucosa performed according to WHO guidelines. A specially prepared color atlas of OML was used for lesion recognition and confirmation during the survey. Among the 35- to 44-year-old subjects, the overall prevalence of OML was found to be 13% in urban men, 6% in urban women, 15% in rural men, and 4% in rural women. The corresponding figures for the 65- to 74-year-olds were 22%, 12%, 26%, and 19%. Tongue lesions and white lesions were relatively common, but denture-related lesions were not. No malignancies or erythroplakia was observed. Age and gender were found to relate to the occurrence of OML. In elderly men, smoking was significantly (p < 0.05) associated with some white lesions and tongue lesions, and alcohol drinking was also associated with some white lesions. In conclusion, tongue lesions and white lesions were relatively common in men, but pre-cancerous lesions were not prevalent.

Adult↗

PubMed2001

Tooth loss, occluding pairs, and prosthetic status of Chinese adults.

The objectives of this analysis were to describe the numbers of teeth lost and those indicated for extraction, dental prosthetic status, and occluding tooth pairs among adults in Southern China and to investigate factors affecting tooth mortality. A sample consisting of 1,573 35- to 44-year-old and 1,515 65- to 74-year-old urban and rural Chinese was examined clinically by calibrated examiners. Teeth not present for any reason were defined as missing (MT). The sum of MT and teeth indicated for extraction (IMT) was defined as adjusted missing teeth (AMT). Only 4.4% of the urban and 3.4% of the rural 65- to 74-year-olds were edentulous. MT were not significantly different between urban and rural residents, but more IMT were found in rural residents. Women, those who had a lower education level, and those who were less wealthy had more AMT in both age groups. Smoking was found to be associated with AMT in the 35- to 44-year-olds. Eighteen percent of the urban and 27% of the rural elderly had no occluding tooth pairs after IMT were accounted for, and only 38% and 30%, respectively, had 10 or more occluding pairs. Fifty-one percent of the urban and 43% of the rural elderly were found to have some form of dental prostheses in either jaw. A partial denture was more common in urban residents in both age groups.

Adult↗

PubMed2000

Biological complications with dental implants: their prevention, diagnosis and treatment.

Biofilms form on all hard non-shedding surfaces in a fluid system, i.e. both on teeth and oral implants. As a result of the bacterial challenge, the host responds by mounting a defence mechanism leading to inflammation of the soft tissues. In the dento-gingival unit, this results in the well-described lesion of gingivitis. In the implanto-mucosal unit, this inflammation is termed "mucositis". If plaque is allowed to accumulate for prolonged periods of time, experimental research has demonstrated that "mucositis" may develop into "periimplantitis" affecting the periimplant supporting bone circumferentially. Although the bony support may be lost coronally, the implant still remains osseointegrated and hence, clinically stable. This is the reason why mobility represents an insensitive, but specific diagnostic feature of "periimplantitis". More sensitive and more reliable parameters of developing and existing periimplant infections are "bleeding on probing", "probing depths" and radiographic interpretation of conventional or subtraction radiographs. Depending on the diagnosis made continuously during recall visits, a maintenance system termed Cumulative Interceptive Supportive Therapy (CIST) has been proposed.

Animals↗

PubMed2000

Interleukin-8 and granulocyte elastase in gingival crevicular fluid in relation to periodontopathogens in untreated adult periodontitis.

BACKGROUND: This study aimed to determine the relationships among interleukin (IL)-8 and granulocyte elastase levels in gingival crevicular fluid (GCF) and the concomitant presence of periodontopathogens in untreated adult periodontitis. METHODS: GCF and subgingival plaque samples were collected from 16 patients with untreated adult periodontitis and 10 healthy control subjects. IL-8 levels were determined by enzyme-linked immunosorbent assay (ELISA). Granulocyte elastase was analyzed with a neutrophilic granulocyte-specific, low molecular weight and chromogenic substrate, L-pyroglutamyl-L-prolyl-L-valine-p-nitroanilide, and the maximal rate of elastase activity (MR-EA) was calculated. Five DNA probes were used to detect the presence of A. actinomycetemcomitans (A.a.), B. forsythus (B.f.), P. gingivalis (P.g.), P. intermedia (P.i.), and T. denticola (T.d.). RESULTS: Lower IL-8 concentrations and higher granulocyte elastase activities were found in patients than in healthy controls as well as in diseased conditions co-infected with B.f., P.g., P.i., and T.d. as compared to healthy conditions without the target species (P <0.05). IL-8 concentrations were positively correlated with MR-EA levels in the periodontitis conditions co-infected with B.f., P.g., P.i., and T.d. (P <0.05). A wide range of IL-8 concentrations was found among 15 patients when the periodontitis condition was characterized by co-infection with B.f., P.g., P.i., and T.d. MR-EA levels in the high IL-8 group of subjects were significantly higher than those in the low IL-8 group of subjects (P <0.01). CONCLUSIONS: The present study shows that the local host-bacteria interactions in untreated periodontitis are diverse in terms of the intensity of inflammatory responses measured by IL-8-related granulocyte elastase activity in GCF. This might reflect different phases of the inflammatory response due to shifts in host-bacteria interactions and therefore be indicative of a range of periodontal disease activity levels.

Actinobacillus Infections↗

PubMed2000

Oral health status and treatment need of 11-13-year-old urban children in Tibet, China.

OBJECTIVE: To describe the oral health status and treatment need of 11-13-year-old children in urban Tibet and to determine if there was a difference in oral health status between the Tibetan and Han children. SURVEY DESIGN AND SUBJECTS: The two largest primary schools in Lhasa, Tibet, were selected and all children aged between 11 and 13 years were surveyed. Each child was interviewed and clinically examined in the schools, using portable equipment, by one of four calibrated examiners. The examination procedures and diagnostic criteria used followed those recommended by the World Health Organization. RESULTS: 347 children (207 Tibetans and 140 Han) were surveyed. Over 90% of the children claimed to brush their teeth at least once a day. Three-quarters had never visited a dentist. Caries prevalence was 44% in the Tibetans and 24% in the Han (P<0.001). The mean DMFT scores of the Tibetans and Han were 0.8 and 0.4 respectively (P<0.001). Only 1% of the children in both ethnic groups had healthy gums (highest CPI score = 0) and about two-thirds of them had calculus. One-third of the children were in need of treatment for dental caries and most of the required treatment items were one-surface fillings but 10% of the children needed extraction. CONCLUSION: Dental caries and treatment need level of both Tibetan and Han children in Tibet was low but their periodontal health status was unsatisfactory.

Adolescent↗

PubMed2000

Comparison of treatment response patterns following scaling and root planing in smokers and non-smokers with untreated adult periodontitis.

The present study was conducted to compare short-term treatment response patterns following scaling and root planing in smoking and non-smoking Chinese patients with untreated adult periodontitis. Thirteen smokers and twelve periodontally matched non-smokers with untreated advanced adult periodontitis were evaluated prior to and at one, three, and six months after scaling and root planing. Probing depths (PD), probing attachment level (PAL) and gingival height (GH) were assessed at clinically healthy, gingivitis and periodontitis sites. PD and PAL were measured using electronic Florida pocket and disk probes, respectively. Non-smokers consistently showed significant gingival shrinkage in gingivitis sites, whereas smokers had no significant change in GH. In periodontitis sites, both groups exhibited significant decreases in PD (p < 0.001) at one month, and a greater reduction of PD was found in non-smokers than in smokers (p < 0.05), the difference being most notable at three months (2.4 +/- 0.2 mm vs. 1.1 +/- 0.3 mm, p < 0.001). Non-smokers showed a consistent gain of attachment in periodontitis sites from 0.5 +/- 0.2 mm at one month (p < 0.05) to 1.2 +/- 0.3 mm at six months (p < 0.001), whereas no significant gain of attachment was found in smokers until six months (0.5 +/- 0.2 mm; p < 0.05). Overall, the reduction of PD positively correlated with baseline PD in both smokers (p < 0.01) and non-smokers (p < 0.001), but when only the sites with an initial PD > or = 5 mm were considered, such a significant correlation was found only in non-smokers (p < 0.05). A positive correlation was also found between the change in PAL and baseline PD solely in non-smokers (p < 0.05). This study indicates that smokers have different treatment response patterns and healing dynamics compared to non-smokers following scaling and root planing, suggesting that for smoking patients a more intensive treatment regimen is needed for a better treatment outcome and reduced risk for further periodontal disease progression.

Adult↗

PubMed1999

Granulocyte elastase activity and PGE2 levels in gingival crevicular fluid in relation to the presence of subgingival periodontopathogens in subjects with untreated adult periodontitis.

This study aimed to determine the association between the levels of granulocyte elastase and prostaglandin E2 (PGE2) in GCE and the concomitant presence of periodontopathogens in untreated adult periodontitis (AP). GCF and subgingival plaque were sampled by paper strips and paper points respectively, from various periodontal sites in 16 AP subjects. Granulocyte elastase activity in GCF was analyzed with a low molecular weight substrate specific for granulocyte elastase, pGluProVal-pNA, and the maximal rate of elastase activity (MR-EA, mAbs/min/site) was calculated. PGE2 levels in GCF were determined by radioimmunoassay. 5 species-specific DNA probes were used to detect the presence of A. actinomyceterncomitans (A.a., ATCC 43718), B. forsythus (B.f, ATCC 43037), P. gingivalis (P.g., ATCC 33277), P. intermedia (P.i., ATCC 33563), and T. denticola (T.d., ATCC 35405), with a sensitivity of 10(3) cells/paper point. No A.a. was detectable from all sites sampled. The predominant combination of species detected was B.f., P.g., P.i. & T.d. and it was significantly higher at periodontitis sites (68%) than at healthy (7%) or gingivitis sites (29%) (p<0.05). Overall, MR-EA values were strongly correlated with PGE2 levels (r=0.655, p<0.001), especially at these periodontitis sites co-infected by B.f., P.g., P.i. & T.d. (r=0.722, p<0.001). The periodontitis sites co-infected by the 4 species were observable from 15 subjects. These sites were sub-grouped into 8 subjects with a high MR-EA and 7 subjects with a low MR-EA. The PGE2 levels in the high MR-EA group were significantly higher than in the low MR-EA group (p<0.05). No significant differences in clinical or bacterial data were found between the two groups. While within the high MR-EA group, similar results were found between the paired periodontitis sites in each subject with highest and lowest MR-EA values. This study shows that the local host response to bacterial challenge in untreated periodontal pockets is diverse in terms of the intensity of inflammatory response measured by granulocyte elastase and PGE2 levels in GCE A more thorough evaluation of the risk for active periodontal disease may involve the combined approaches to the test of the dynamic bacteria-host relations.

Adult↗

PubMed1998

Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in young Chinese adults.

The aim of this study was to determine the presence or absence of Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis in young Chinese adults and to examine the A. actinomycetemcomitans isolates from positive subjects with regard to the serotype distribution, presence of the leukotoxin gene lktA and the promoter for the leukotoxin operon as well as the incidence of phage Aa phi 23. Sixty subjects, working in a knitting factory in the Province of Guangzhou, People's Republic of China, were investigated. Subgingival microbial samples were taken from both upper first molars. They were cultured both anaerobically and in 5% CO2. P. gingivalis was found in 33 subjects. On average, it constituted 7% of the total anaerobic cultivable counts. A. actinomycetemcomitans was detected in 37 subjects of which seven yielded counts > 10(5). Twenty-one subjects were positive for both organisms. A. actinomycetemcomitans serotype a was found in 9 subjects, serotype c was found in 23 and serotype e in 5. A. actinomycetemcomitans serotypes b and d were not detected in any subjects. Presence of the leukotoxin gene lktA was demonstrated for all A. actinomycetemcomitans isolates; however, none of the A. actinomycetemcomitans strains from the present study had a deletion in the promoter region of the leukotoxin operon. The results of this investigation show a high frequency of the putative periodontal pathogens P. gingivalis and A. actinomycetemcomitans and corroborate the concept that there is variation in virulence and pathogenic potential among isolates from different subjects.

Adolescent↗

PubMed1998

Practical periodontal screening and diagnosis.

The differences in approach between screening for and diagnosis of periodontal diseases are highlighted. The Periodontal Screening and Recording procedure is discussed in terms of its evolution and current application. For patients screened and found to have more advanced periodontal problems a panoramic dental radiograph with restricted supplemented periapicals are recommended. A comprehensive clinical periodontal examination should be performed for these patients, but it is argued that this may be performed after the initial hygiene phase of treatment. In establishing a diagnosis it is suggested that attention be paid to possible risk exposures. Newer, non-anatomic diagnostic procedures are discussed in principle and it is concluded that these do not have a practical application at present.

Biomarkers↗

PubMed1997

Dentistry's development in Hong Kong.

The history of dentistry in Hong Kong is described from the time prior to the colonisation by the British to the present day. With the imminent, and historic, hand over of the present territory from British to Chinese rule on 30 June 1997, the authors also touch on the future of oral care in Hong Kong.

China↗