Porphyromonas gingivalis and Treponema denticola Mixed Microbial Infection in a Rat Model of Periodontal Disease

Porphyromonas gingivalis and Treponema denticola are periodontal pathogens that express virulence factors associated with the pathogenesis of periodontitis. In this paper we tested the hypothesis that P. gingivalis and T. denticola are synergistic in terms of virulence; using a model of mixed microbial infection in rats. Groups of rats were orally infected with either P. gingivalis or T. denticola or mixed microbial infections for 7 and 12 weeks. P. gingivalis genomic DNA was detected more frequently by PCR than T. denticola. Both bacteria induced significantly high IgG, IgG2b, IgG1, IgG2a antibody levels indicating a stimulation of Th1 and Th2 immune response. Radiographic and morphometric measurements demonstrated that rats infected with the mixed infection exhibited significantly more alveolar bone loss than shaminfected control rats. Histology revealed apical migration of junctional epithelium, rete ridge elongation, and crestal alveolar bone resorption; resembling periodontal disease lesion. These results showed that P. gingivalis and T. denticola exhibit no synergistic virulence in a rat model of periodontal disease

Immunization with the RgpA-Kgp Proteinase-Adhesin Complexes of Porphyromonas gingivalis Protects against Periodontal Bone Loss in the Rat Periodontitis Model

A major virulence factor of Porphyromonas gingivalis is the extracellular noncovalently associated complexes of Arg-X- and Lys-X-specific cysteine proteinases and adhesins designated the RgpA-Kgp complexes. In this study we investigated the ability of RgpA-Kgp as an immunogen to protect against P. gingivalis-induced periodontal bone loss in the rat. Specific-pathogen-free Sprague-Dawley rats were immunized with either formalin-killed whole P. gingivalis ATCC 33277 cells with incomplete Freund's adjuvant, RgpA-Kgp with incomplete Freund's adjuvant, or incomplete Freund's adjuvant alone. The animals were then challenged by oral inoculation with live P. gingivalis ATCC 33277 cells. Marked periodontal bone loss was observed in animals immunized with incomplete Freund's adjuvant alone; this bone loss was significantly (P < 0.05) greater than that detected in animals immunized with formalin-killed whole cells or RgpA-Kgp or in unchallenged animals. There was no significant difference in periodontal bone loss between animals immunized with formalin-killed whole cells and those immunized with RgpA-Kgp. The bone loss in these animals was also not significantly different from that in unchallenged animals. DNA probe analysis of subgingival plaque samples showed that 100% of the animals immunized with incomplete Freund's adjuvant alone and challenged with P. gingivalis ATCC 33277 were positive for the bacterium. However, P. gingivalis ATCC 33277 could not be detected in subgingival plaque samples from animals immunized with formalin-killed whole cells or with RgpA-Kgp. Immunization with formalin-killed whole cells or RgpA-Kgp induced a high-titer serum immunoglobulin G2a response. Western blot analysis of RgpA-Kgp using pooled protective antisera taken from rats immunized with RgpA-Kgp revealed immunodominant bands at 44, 39, and 27 kDa. In conclusion, immunization with RgpA-Kgp restricted colonization by P. gingivalis and periodontal bone loss in the rat

The cost-effectiveness of supportive periodontal care: a global perspective

AIM: To evaluate the cost-effectiveness of supportive periodontal care (SPC) provided in generalist and periodontal specialist practices under publicly subsidized or private dental care. MATERIAL AND METHODS: SPC cost data and the costs of replacing teeth were synthesized with estimates of the effectiveness of SPC in preventing attachment and tooth loss and adjusted for differences in clinician's time. Incremental cost-effectiveness ratios were calculated for both outcomes assuming a time horizon of 30 years. RESULTS: SPC in specialist periodontal practice provides improved outcomes but at higher costs than SPC provided by publicly subsidized or private systems. SPC in specialist periodontal practice is usually more cost-effective than in private dental practice. For private dental practices in Spain, United Kingdom and Australia, specialist SPC is cost-effective at modest values of attachment loss averted. Variation in the threshold arises primarily from clinician's time. CONCLUSION: SPC in specialist periodontal practice represents good value for money for patients (publicly subsidized or private) in the United Kingdom and Australia and in Spain if they place relatively modest values on avoiding attachment loss. For patients in Ireland, Germany, Japan and the United State, a higher valuation on avoiding attachment loss is needed to justify SPC in private or specialist practices

Population burden of betel quid abuse and its relation to oral premalignant disorders in south, southeast, and east Asia: an Asian betel-quid consortium study

Objectives. We investigated the population burden of betel quid abuse and its related impact on oral premalignant disorders (OPDs) in South, Southeast, and East Asia. Methods. The Asian Betel-Quid Consortium conducted a multistage sampling of 8922 representative participants from Taiwan, Mainland China, Malaysia, Indonesia, Nepal, and Sri Lanka. Participants received an interviewer-administered survey and were examined for oral mucosal disorders. Results. The prevalence of betel quid abuse was 0.8 to 46.3 across 6 Asian populations. The abuse frequency was over 40.5 for current chewers, with the highest proportion in Nepalese and Southeast Asian chewers (76.9?99.6). Tobacco-added betel quid conferred higher abuse rates (74.4?99.6) among Malaysian, Indonesian, and Sri Lankan men than did tobacco-free betel quid (21.8?89.1). Gender, lower education level, younger age at chewing initiation, and clustering of familial betel quid use significantly contributed to higher abuse rates. Indonesian betel quid abusers showed the highest prevalence of OPDs and had a greater risk of OPDs than did nonabusers. Conclusions. Betel quid abuse is high in regions of Asia where it is customarily practiced, and such abuse correlates highly with OPDs. By recognizing abuse-associated factors, health policies and preventive frameworks can be effectively constructed to combat these oral preneoplasms

Intercountry prevalences and practices of betel-quid use in south, southeast and eastern asia regions and associated oral preneoplastic disorders: An international collaborative study by asian betel-quid consortium of south and east Asia

Health risks stemming from betel-quid (BQ) chewing are frequently overlooked by people. Updated epidemiological data on the increased BQ use among Asian populations using comparable data collection methods have not been widely available. To investigate the prevalence, patterns of practice and associated types of oral preneoplastic disorders, an intercountry Asian Betel-quid Consortium study (the ABC study) was conducted for Taiwan, Mainland China, Malaysia, Indonesia, Nepal and Sri Lanka. A random sample of 8,922 subjects was recruited, and the data were analyzed using survey-data modules adjusted for the complex survey design. Chewing rates among men (10.7-43.6) were significantly higher than women (1.8-34.9) in Taiwan, Mainland China, Nepal and Sri Lanka, while women's rates (29.5-46.8) were higher than that for men (9.8-12.0) in Malaysia and Indonesia. An emerging, higher proportion of new-users were identified for Hunan in Mainland China (11.1-24.7), where Hunan chewers have the unique practice of using the dried husk of areca fruit rather than the solid nut universally used by others. Men in the Eastern and South Asian study communities were deemed likely to combine chewing with smoking and drinking (5.6-13.6). Indonesian women who chewed BQ exhibited the highest prevalence of oral lichen planus, oral submucous fibrosis and oral leukoplakia (9.1-17.3). Lower schooling, alcohol drinking and tobacco smoking were identified as being associated with BQ chewing. In conclusion, the ABC study reveals the significant cultural and demographic differences contributing to practice patterns of BQ usage and the great health risks that such practices pose in the Asian region. This record was migrated from the OpenDepot repository service in June, 2017 before shutting down

Intercountry prevalences and practices of betel-quid use in south, southeast and eastern Asia regions and associated oral preneoplastic disorders: an international collaborative study by Asian betel-quid consortium of south and east Asia

Abstract Health risks stemming from betel-quid (BQ) chewing are frequently overlooked by people. Updated epidemiological data on the increased BQ use among Asian populations using comparable data collection methods have not been widely available. To investigate the prevalence, patterns of practice and associated types of oral preneoplastic disorders, an intercountry Asian Betel-quid Consortium study (the ABC study) was conducted for Taiwan, Mainland China, Malaysia, Indonesia, Nepal and Sri Lanka. A random sample of 8,922 subjects was recruited, and the data were analyzed using survey-data modules adjusted for the complex survey design. Chewing rates among men (10.7-43.6%) were significantly higher than women (1.8-34.9%) in Taiwan, Mainland China, Nepal and Sri Lanka, while women's rates (29.5-46.8%) were higher than that for men (9.8-12.0%) in Malaysia and Indonesia. An emerging, higher proportion of new-users were identified for Hunan in Mainland China (11.1-24.7%), where Hunan chewers have the unique practice of using the dried husk of areca fruit rather than the solid nut universally used by others. Men in the Eastern and South Asian study communities were deemed likely to combine chewing with smoking and drinking (5.6-13.6%). Indonesian women who chewed BQ exhibited the highest prevalence of oral lichen planus, oral submucous fibrosis and oral leukoplakia (9.1-17.3%). Lower schooling, alcohol drinking and tobacco smoking were identified as being associated with BQ chewing. In conclusion, the ABC study reveals the significant cultural and demographic differences contributing to practice patterns of BQ usage and the great health risks that such practices pose in the Asian region

Population Burden of Betel Quid Abuse and Its Relation to Oral Premalignant Disorders in South, Southeast, and East Asia: An Asian Betel-Quid Consortium Study

Abstract Objectives: We investigated the population burden of betel quid abuse and its related impact on oral premalignant disorders (OPDs) in South, Southeast, and East Asia. Methods: The Asian Betel-Quid Consortium conducted a multistage sampling of 8922 representative participants from Taiwan, Mainland China, Malaysia, Indonesia, Nepal, and Sri Lanka. Participants received an interviewer-administered survey and were examined for oral mucosal disorders. Results: The prevalence of betel quid abuse was 0.8% to 46.3% across 6 Asian populations. The abuse frequency was over 40.5% for current chewers, with the highest proportion in Nepalese and Southeast Asian chewers (76.9%-99.6%). Tobacco-added betel quid conferred higher abuse rates (74.4%-99.6%) among Malaysian, Indonesian, and Sri Lankan men than did tobacco-free betel quid (21.8%-89.1%). Gender, lower education level, younger age at chewing initiation, and clustering of familial betel quid use significantly contributed to higher abuse rates. Indonesian betel quid abusers showed the highest prevalence of OPDs and had a greater risk of OPDs than did nonabusers. Conclusions: Betel quid abuse is high in regions of Asia where it is customarily practiced, and such abuse correlates highly with OPDs. By recognizing abuse-associated factors, health policies and preventive frameworks can be effectively constructed to combat these oral preneoplasms