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Although there has been a decrease in the prevalence and the severity of dental caries in children over the past few decades, the benefits have not been equally shared by many low-income or underserved children in many industrialised countries, or children in developing countries. Dental caries is still the most common and challenging dental disease in children for a clinician to treat. Silver diamine fluoride (SDF) has been in use to arrest dental caries in many countries. A 38% (44,800 ppm fluoride ions) SDF solution is commonly used to arrest caries in primary teeth of children, especially those children who are young and difficult to manage. Application of SDF to arrest dental caries is a non-invasive procedure that is quick and simple to use. However, it stains the carious teeth and turns the arrested caries black. It also has an unpleasant metallic taste that is not liked by patients, especially children. The low cost of SDF and its simplicity in application suggest that SDF is an appropriate therapeutic agent for use in community dental health projects. Reports of available studies found no severe pulpal damage after SDF application. The current literature suggests that SDF can be an effective agent in preventing new caries and in arresting dental caries in the primary teeth of the children. It can be used to arrest caries progression in very young children who are less cooperative, and it allows definitive restoration to be performed when they grow older and become more receptive to dental procedures. [ABSTRACT FROM AUTHOR]

Unlike other fluoride-based caries preventive agents, silver diamine fluoride (SDF) can simultaneously prevent and arrest coronal and root dentine caries. The profound clinical success of SDF has drawn many clinicians and researchers to study the mechanism of SDF in arresting dentine caries. This critical review discusses how silver and fluoride contribute to caries arrest, in terms of their effects on bacteria as well as on the mineral and organic content of dentine. Silver interacts with bacterial cell membrane and bacterial enzymes, which can inhibit bacterial growth. Silver can also dope into hydroxyapatite and have an antibacterial effect on silver-doped hydroxyapatite. Furthermore, silver is also a strong inhibitor of cathepsins and inhibits dentine collagen degradation. Early studies proposed that silver hardened caries lesions by forming silver phosphate. However, recent studies found that little silver phosphate remained on the arrested dentine lesion. The principal silver precipitate was silver chloride, which could not contribute to the significant hardening of the arrested lesions. On the other hand, fluoride enhances mineral formation by forming fluorohydroxyapatite with reduced solubility. A significant increase in microhardness occurs with an elevated level of calcium and phosphorus but not silver on the surface layer of the arrested dentine caries lesion following SDF treatment. Fluoride also inhibits matrix metalloproteinases activities and therefore inhibits dentine collagen degradation. The combination of silver and fluoride in an alkaline solution has a synergistic effect in arresting dentine caries. The alkaline property of SDF provides an unfavorable environment for collagen enzyme activation. Understanding the mechanisms of SDF in arresting dentine caries helps clinicians to develop appropriate protocols for the use of SDF in clinical care. [ABSTRACT FROM AUTHOR]

This randomized clinical trial aimed to compare the adverse effects and parental satisfaction following the different regimes of silver diamine fluoride (SDF) treatment among preschool children. A total of 888 preschool children who had active dentin caries received different SDF application regimes: group 1, 12% SDF applied annually; group 2, 12% SDF applied semiannually; group 3, 38% SDF applied annually; and group 4, 38% SDF applied semiannually. Information on adverse effects-including tooth or gum pain, gum swelling, gum bleaching, and systemic toxicity-was collected through a parent-reported questionnaire within 1 wk after every SDF or placebo application. Information of parental satisfaction on children's dental appearance was collected at baseline and 30-mo examination. At the 30 mo, 799 children (90%) remained in the study. No acute systemic illness or major adverse effect was reported. No differences of all minor adverse effects among the 4 groups were found ( P > 0.05). Overall, prevalence of tooth and gum pain as perceived by patients and reported by parents was 6.6%, while gum swelling and gum bleaching were 2.8% and 4.7%, respectively. Blackening of carious lesions was common among all groups, with 36.7%, 49.5%, 65.6% and 76.3% in groups 1 to 4, respectively (χ2 test, P < 0.001). The proportion of parents who were satisfied with their children's dental appearance in groups 1 to 4 was as follows: 67.6%, 61.5%, 70.8%, and 62.3%, respectively (χ2 test, P > 0.05). Based on parental reporting, SDF does not cause acute systemic illness. Tooth or gum pain, gum swelling, and gum bleaching were uncommon and not significantly different among the study groups. Parental satisfaction with children's dental appearance was similar among all groups. The use of SDF following the study protocol for caries arrest is safe for preschool children. Collecting information on parental satisfaction and adverse effects is beneficial for dental professionals when deciding to adopt SDF treatment for preschool children (ClinicalTrials.gov NCT02385474). [ABSTRACT FROM AUTHOR]

This 30-mo randomized clinical trial compared the effectiveness of 2 concentrations (12% or 38%) of silver diamine fluoride (SDF) and 2 periodicity of application (once or twice a year) in arresting cavitated dentin caries in primary teeth. Children aged 3 to 4 y who had at least 1 active cavitated caries lesion were enrolled and randomly allocated into 4 groups for intervention. Group 1 had 12% SDF applied annually (every 12 mo), group 2 had 12% SDF applied semiannually (every 6 mo), group 3 had 38% SDF applied annually, and group 4 had 38% SDF applied semiannually. Clinical examinations were performed semiannually in kindergarten by a single examiner to investigate whether the SDF-treated caries became arrested. A total of 888 children with 4,220 decayed tooth surfaces received SDF application at baseline, and 799 (90.0%) children with 3,790 surfaces (89.8%) were evaluated at the 30-mo examination. The caries arrest rates were 55.2%, 58.6%, 66.9%, and 75.7% for groups 1, 2, 3, and 4, respectively ( P < 0.001). Caries treated with 38% SDF had a higher chance of becoming arrested than those treated with 12% SDF (odds ratio [OR], 1.98; 95% confidence interval [CI], 1.51-2.60, P < 0.001). The interaction between frequency of SDF application and visible plaque index (VPI) score was significant ( P = 0.017). Among those children who received annual SDF application, children with a higher VPI score had a lower chance to have their caries become arrested (OR, 0.59, 95% CI, 0.49-0.72). In conclusion, SDF at a concentration of 38% is more effective than that of 12% in arresting active caries in primary teeth. For children with poor oral hygiene, caries arrest rate of SDF treatment can be increased by increasing the frequency of application from annually to semiannually ( ClinicalTrials.gov NCT02385474). [ABSTRACT FROM AUTHOR]

Silver diamine fluoride (SDF) is found to promote remineralization and harden the carious lesion. Hydroxyapatite crystallization is a crucial process in remineralization; however, the role of SDF in crystal formation is unknown. We designed an in vitro experiment with calcium phosphate with different SDF concentrations (0.38, 1.52, 2.66, 3.80 mg/mL) to investigate the effect of this additive on the nucleation and growth of apatite crystals. Two control groups were also prepared-calcium phosphate (CaCl2·2H2O + K2HPO4 in buffer solution) and SDF (Ag[NH3]2F in buffer solution). After incubation at 37 oC for 24 h, the shape and organization of the crystals were examined by bright-field transmission electron microscopy and electron diffraction. Unit cell parameters of the obtained crystals were determined with powder X-ray diffraction. The vibrational and rotational modes of phosphate groups were analyzed with Raman microscopy. The transmission electron microscopy and selected-area electron diffraction confirmed that all solids precipitated within the SDF groups were crystalline and that there was a positive correlation between the increased percentage of crystal size and the concentration of SDF. The powder X-ray diffraction patterns indicated that fluorohydroxyapatite and silver chloride were formed in all the SDF groups. Compared with calcium phosphate control, a contraction of the unit cell in the a-direction but not the c-direction in SDF groups was revealed, which suggested that small localized fluoride anions substituted the hydroxyl anions in hydroxyapatite crystals. This was further evidenced by the Raman spectra, which displayed up-field shift of the phosphate band in all the SDF groups and confirmed that the chemical environment of the phosphate functionalities indeed changed. The results suggested that SDF reacted with calcium and phosphate ions and produced fluorohydroxyapatite. This preferential precipitation of fluorohydroxyapatite with reduced solubility could be one of the main factors for arrest of caries lesions treated with SDF. [ABSTRACT FROM AUTHOR]

The aim of this study was to explore the relationship between early childhood caries (ECC) and relevant socio-economic, behavioural and biological experiences in the life course of children. A cross-sectional study of 2-year-old children was analysed. A questionnaire collected socio-economic and behavioural data during the first two years of the participants' life. Caries experience was recorded at the level of cavitation and oral hygiene was assessed using the Visible Plaque Index (VPI). Microbiological investigation collected information on colony-forming units (CFU) of Streptococcus mutans ( S. mutans). The outcome was ECC. Bivariate and multiple logistic regression analyses were performed. The study included 394 children, with 109 having ECC and 285 being caries-free. The mean decayed, missing and filled primary teeth (dmft) score of the ECC group was 3.65 ± 3.12, with decayed teeth making up 100% of the score. The results of the final logistic regression analysis showed that ECC was significantly associated with the mother's schooling at child's birth [<12 years vs. ≥12 years, OR = 1.80], VPI score [>60% vs. 0-20%, OR = 5.71], and S. mutans [≥10CFU/ml vs. 0 CFU/ml, OR = 3.80]. Social, behavioural and biological factors during the life course of 2-year-old children in southern China are associated with the development of ECC. [ABSTRACT FROM AUTHOR]

Objectives: To compare the prevalence and severity of developmental defects of enamel (DDE) among subjects whose maxillary incisors developed during periods with different concentrations of fluoride in the public water supply. Methods: Standardized intra-oral photographs of random samples of 12-year-old children were collected in 1983, 1991 and 2001 (n = 1,990) in Hong Kong and assessed for DDE by a trained masked examiner. The fluoride concentrations in the public water supply at the times when the enamel on their maxillary incisors developed were 1.0, 0.7 and 0.5 ppm, respectively. Results:The mouth prevalence of DDE for these children (based on the maxillary incisors) were 92.1, 55.8 and 35.2% in the years 1983, 1991 and 2001, respectively (p < 0.001). Most of these children were affected by diffuse opacities (89.3% in 1983, 48.5% in 1991 and 32.4% in 2001, p < 0.001). Marked differences in the mean number of teeth affected by DDE (p < 0.001) and in the maximum extent of DDE (p ≦ 0.002) between 1983, 1991 and 2001 were also observed. Conclusions: A decrease in the prevalence and severity of DDE among the maxillary incisor teeth of the children corresponded to the reductions in the concentration of fluoride in the water during the time of enamel development. Copyright © 2006 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The objective of this study was to assess the effect of six-monthly professional applications of chlorhexidine varnish on the prevention of dental caries in primary molars in Chinese preschool children. In a double-blinded, randomized, placebo-controlled clinical trial, 334 children aged 4-5 years were randomly divided into two groups. Children in the test group received six-monthly applications of a 40% chlorhexidine varnish, and the control children received a placebo varnish. Caries status of the children was assessed by two calibrated examiners at baseline and after 24 months, according to criteria recommended by the World Health Organization. The two-year mean caries increments in the test and the control group children were 1.0 and 1.6 decayed, missing, or filled molar surfaces (dmfs-molar), respectively, a 37.3% reduction (t test, p = 0.036). No side-effects were found. It was concluded that six-monthly applications of chlorhexidine varnish were effective in reducing the incidence of dental caries in primary molars. [ABSTRACT FROM AUTHOR]

The recording of multiple interval-censored failure times is common in dental research. Modeling multilevel data has been a difficult task. This paper aims to use the Bayesian approach to analyze a set of multilevel clustered intervalcensored data from a clinical study to investigate the effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting active dentin caries in Chinese pre-school children. The time to arrest dentin caries on a surface was measured. A three-level random-effects Weibull regression model was used. Analysis was performed with WinBUGS. Results revealed a strong positive correlation (0.596) among the caries lesions' arrest times on different surfaces from the same child. The software WinBUGS made the above complicated estimation simple. In conclusion, the annual application of silver diamine fluoride on caries lesions, and caries removal before the application, were found to shorten the arrest time. [ABSTRACT FROM AUTHOR]

Untreated dental caries in Chinese pre-school children is common. This prospective controlled clinical trial investigated the effectiveness of topical fluoride applications in arresting dentin caries. Three hundred seventy-five children, aged 3-5 years, with carious upper anterior teeth were divided into five groups. Children in the first and second groups received annual applications of silver diamine fluoride solution (44,800 ppm F). Sodium fluoride varnish (22,600 ppm F) was applied every three months to the lesions of children in the third and fourth groups. For children in the first and third groups, soft carious tissues were removed prior to fluoride application. The fifth group was the control. Three hundred eight children were followed for 30 months. The respective mean numbers of arrested carious tooth surfaces in the five groups were 2.5, 2.8, 1.5, 1.5, and 1.3 (p < 0.001). Silver diamine fluoride was found to be effective in arresting dentin caries in primary anterior teeth in pre-school children. [ABSTRACT FROM AUTHOR]

Dental caries in Chinese pre-school children is common, and restorative treatment is not readily available. This prospective controlled clinical trial investigated the effectiveness of topical fluoride applications in arresting dentin caries. We divided 375 children (aged 3-5 yrs) with carious upper anterior teeth into five groups. Children in the first and second groups received annual applications of silver diamine fluoride solution (44,800 ppm F). NaF varnish (22,600 ppm F) was applied every three months onto the lesions of children in the third and fourth groups. For children in the first and third groups, soft carious tissues were removed prior to fluoride application. The fifth group was the control. We followed 341 children for 18 months. The mean numbers of new caries surfaces in the five groups were 0.4, 0.4, 0.8, 0.6, and 1.2, respectively (p =0.001). The respective mean numbers of arrested carious tooth surfaces were 2.8, 3.0, 1.7, 1.5, and 1.0 (p < 0.001). [ABSTRACT FROM AUTHOR]

Objective: To compare the clinical performance of two glass-ionomer cements, ChemFlex (Dentsply DeTrey) and Fuji IX GP (GC), when used with the atraumatic restorative treatment (ART) approach in China.Methods: Eighty-nine school children aged between 6 and 14 years who had bilateral matched pairs of carious posterior teeth were included. A split-mouth design was used in which the two materials were randomly placed on contralateral sides. The performance of the restorations was assessed directly and also indirectly from die-stone replicas at baseline and after 6, 12, and 24 months.Results: The 24-month cumulative survival rates of ART restorations in the primary teeth were 93 and 90% for the ChemFlex and Fuji IX GP class I restorations, respectively, while 40 and 46% of class II restorations placed with the respective materials were satisfactory. In the permanent dentition, only class I restorations were involved and the cumulative survival rates were 95 and 96% for ChemFlex and Fuji IX GP. For the primary teeth after 24 months, net mean occlusal wear was 87 microm for ChemFlex and 85 microm for Fuji IX GP. The occlusal wear in the permanent teeth was 75 microm for ChemFlex and 79 microm for Fuji IX GP.Conclusion: The clinical performance of both materials over a 24-month period was similar and the survival rates of class I ART restorations in both primary and permanent teeth were high. [ABSTRACT FROM AUTHOR]

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 1573 35- to 44-year-old and 1515 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 3.400 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. [ABSTRACT FROM AUTHOR]

Southern China is the most prosperous part of China, but information useful for oral care planning is very limited. A large-scale epidemiological survey was conducted in 1996-97. The objectives of this report were to describe the coronal and root caries of the adult Southern Chinese and to analyze the influence of selected demographic and socio-economic factors on the disease pattern. A total sample of 1573 35- to 44- year-olds and 1515 65- to 74-year-olds from 8 urban and 8 rural survey sites in Guangdong Province participated in an oral health interview and underwent clinical examination. World Health Organization examination procedures and diagnostic criteria were used. The weighted mean DMFT scores of the middle-aged and the elderly subjects were 4.8 and 16.1, respectively. People living in rural areas had a higher DMFT score than those living in urban areas (4.9 vs. 4.3 in the 35- to 44-year-olds and 16.5 vs. 14.7 in the 65- to 74- year-olds). In both age groups, MT was the major component of the DMFT score. Analysis of covariance showed that women and those who were economically less well off had higher DMFT scores in both age groups. The weighted prevalence rates of decayed/filled roots were 12% and 37%, with a mean of 0.2 and 0.7 teeth affected, in the middle-aged and the elderly, respectively. In conclusion, socio-economic factors had a considerable effect on the dental caries status of adults in Southern China. [ABSTRACT FROM AUTHOR]

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 1573 35- to 44-year-old and 1515 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. [ABSTRACT FROM AUTHOR]

Only recently have behavioral aspects been taken into consideration in oral health studies in China; thus, relevant information on perceptions in adult Chinese about oral health care is inadequate. In 1996-97, a large-scale oral epidemiological study was conducted in Southern China. Among its objectives were to describe the oral health knowledge, attitudes, and practices of the urban and rural adults living in Southern China and to analyze the influence of selected demographic and socio-economic factors. From 8 urban and 8 rural communities in Guangdong Province, 1573 35- to 44-year-olds and 1515 65- to 74-year-olds were sampled. Specially trained interviewers from the staff of local government or hospitals conducted face-to-face structured interviews. Almost all of the middle-aged and more than 90% of the dentate elderly surveyed claimed that they brushed their teeth every day and used toothpaste during tooth brushing, but awareness about fluoride content was lacking. The respondents had poor oral health knowledge but positive attitudes toward oral health, providing a basis for more community-based oral health education programs, especially targeting adults who are less-well- educated and have fewer socio-economic advantages. [ABSTRACT FROM AUTHOR]

A population's utilization of dental services is an important parameter in oral health care planning, which has rarely been studied in China. The objectives of this report were to describe the dental service utilization pattern of middle-aged and elderly Chinese and to analyze the influence of selected variables on the use of dental services. A Guangdong Province population of 1573 35- to 44-year-olds and 1515 65- to 74-year-olds recruited from urban and rural communities was interviewed in their local dialect. It was found that 23% of the middle-aged and 24% of the elderly subjects had visited a dentist within the preceding year. The two most commonly cited reasons for not having seen a dentist for at least 3 years were: no perceived need, and no serious dental problems. Among subjects who had visited a dentist within 3 years, the 3 most commonly received treatments were: fillings, extractions, and dental prostheses. Furthermore, a logistic regression analysis showed that women, subjects who lived in urban areas, were better educated, were wealthier, and had better oral health knowledge were more likely to be a recent dental service user. In conclusion, dental service utilization among the adult Southern Chinese was found to be low, problem-driven, and influenced by some socio-economic factors. [ABSTRACT FROM AUTHOR]

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 (κ=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. [ABSTRACT FROM AUTHOR]

The objectives of the study were to describe the oral health status and treatment needs of the 5- to 6-year- old and 12-year-old children in Southern China; to describe the patterns of oral health behaviors, knowledge, and attitudes among the 12-year-olds; and to assess the effects of socio-behavioral factors on the 12-year-old children's dental caries experiences. The study sample was comprised of 1587 5- to 6-year-old and 1576 12-year-old urban and rural schoolchildren living in Guangdong Province. Three calibrated dentists clinically examined the children, and trained interviewers interviewed the 12- year-olds. Caries prevalence of the 5- to 6-year-old children was high (urban 78% vs. rural 86%); the mean dmft of the urban and rural children was 4.8 and 7.0, respectively. The caries prevalence and mean DMFT score of the 12-year-olds were 41% and 0.9 (urban) and 42% and 0.9 (rural). Only 2% of the 12- year-olds exhibited no calculus or gingival bleeding, while more than 70% had calculus. In conclusion, there is an urgent need for establishing caries- preventive activities for preschool children. The prevalence of caries among the 12-year-olds was not high, but their periodontal condition was unsatisfactory. Knowledge about gum bleeding and the use of fluoride was low. More oral health education activities should be organized, especially for the rural children. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the presence or absence of Actinobacillus actinomycetemconiitans and Porphyrornonas gingivalis in young Chinese adults and to examine the A. actznomycetemcornitans 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 Aφ23. 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. actznornycetemcomitans was detected in 37 subjects of which seven yielded counts >105, Twenty-one subjects were positive for both organisms. A. actinornyceterncomitans serotype a was found in 9 subjects, serotype e was found in 23 and serotype e in 5. A. actinornyceterncomitans serotypes b and d were not detected in any subjects. Presence of the leukotoxin gene lktA was demonstrated for all A. actinornycetemcomitans isolates; however, none of the A. actinomyceterneornitans 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. actinornyceterncorniians and corroborate the concept that there is variation in virulence and pathogenic potential among isolates from different subjects. [ABSTRACT FROM AUTHOR]

A random sample of patients who had received Co-Cr removable partial dentures (RPD) 5 to 6 years previously from a dental teaching hospital in Hong Kong were included in the study. Of 192 subjects, 189 responded to a questionnaire. Only 100 (53%) of them were still wearing their RPDs. These subjects were offered a clinical examination, which was accepted by 87 of them. The clinical examination revealed that there were significantly more sites in contact with the RPD, compared to sites not in contact, that harbored plaque, exhibited gingival bleeding after probing, showed a probing depth of 4 mm or more, and appeared with a periodontal attachment loss of 4 mm or more. Patients who had regular dental visits had proportionally fewer tooth sites with plaque and gingival bleeding. Despite a low caries incidence in the sample, root caries was found to be significantly associated with contact with the RPD; coronal caries was not. Denture- related mucosal lesions were found in only 7% of the patients. It was concluded that the higher prevalence of plaque, gingivitis, and gingival recession, as well as the higher incidence of root caries, justifies a special emphasis on regularoral hygiene reinforcement for RPD wearers. [ABSTRACT FROM AUTHOR]