Antibacterial Properties of Nano Silver-containing Orthodontic Cements in the Rat Caries Disease Model

The purpose of this study was to evaluate the antibacterial properties of experimental nano silver-containing cements（NSCs） using rat caries disease model. Nano silver base inorganic antibacterial powder was added to the reinforced glass ionomer cement at three different weight ratios to obtain a series of nano silver-containing cements, then two orthodontic cement products and three NSC samples were implanted into rat caries disease model, and their antibacterial properties were evaluated by the scanning electron microscope（SEM）. Moreover, the rat caries disease model were established by inoculating cariogenic bacteria S mutans into antibiotics treated rat mouths and feeding with cariogenic diet. The tested materials were bonded on the surface of the buccal half crowns of the upper fi rst premolar, and then fi xed under the rats＇ front teeth lingual side to acquire enough retention. The SEM results indicated that the growth of streptococcus mutans was very active in group of Transbond XT. One month later, S mutans scattered on the GC Fuji ORTHO LC surface, and then the number signifi cantly increased and arranged in chains after three months. In groups of NSC2, NSC3 and NSC4, the number of S mutans presented the downward trend and tended to disperse individually with the increase of silver nanoparticle content. We may conclude that the incorporation of silver nanoparticle enhanced GC Fuji ORTHO LC the adhesion restrain and killing effect to S mutans.

Risks Factors of Caries and Periodontal Diseases in the Patients, after 5 Years Use a Partial Removable Denture

Objective: The goal of the removable partial denture is to restore impaired esthetics and masticatory function by replacing missing teeth. The aim of this study was to establish a possible correla-tion between removable partial denture in acrylic resin use after 5 years and dental diseases. Materials and Methods: Partially edentulous patients presenting for removable denture treatment at the Prosthodontics service of the Affiliated Hospital of Kinshasa University, Democratic Republic of Congo were assessed in this study. Patients were randomly assigned into 2 groups: Denture and non-denture group. Caries and periodontal diseases were compared between both groups. Statistical significance was set at p < 0.05. Results: The average age in the denture and non-denture-group was 53.15 (±SD 22.05) and 31.59 (±SD 11.98) years. Out of 160 teeth were decayed, both 110 teeth (68.75%) in the denture-group and 50 teeth (31.25%) in the non-denture group. The DMFT index calculated at start time of the study was 0.2 for both groups, after five years was 7.1 for the denture-group and 2.6 for the non-denture-group. The plaque index in the denture-group had an index of 1 and that of non-denture-group was 0.5. Conclusion: The relationship has been found between patients’ wearers a RPD and dental diseases.

Prevalence and Years of Life Lost due to Disability from Dental Caries among Children and Adolescents in Western China,1990-2015

Objective To analyze the prevalence and years lived with disability （YLD） from dental caries among children and adolescents and the time trends over the past two decades in Sichuan province, the largest province in west China. Methods Based on the Global Burden of Disease Study 2015 （GBD2015）, which systematically assessed the epidemiological characteristics of major diseases and their transitions by country and region from 1990 to 2015, we extracted the estimated results for China. We then used the Bayesian meta-regression method to estimate the sex- and age-specific prevalences and YLDs from dental caries among children and adolescents under 15 years old in Sichuan province and compared them with global and national indicators for the same period. Results In 2015, there were almost 6 million cases of dental caries in children and adolescents （aged 〈 15 years） in Sichuan province, accounting for 6% of the total cases in China. For children under 5 years, the prevalence of deciduous caries was 55.9%, and the YLDs value was 10.8 per 100,000, while it was 24.3% and 5.1 per 100,000 respectively among 5- to 14-year-olds; for those aged 5 to 14 years, the prevalence of permanent caries was 21.5%, and the YLDs value was 11.5 per 100,000. From 1990 to 2015, the prevalence of dental caries for children under 5 years increased substantially, by 16.2%, and the YLDs increased by 8.7%. Among those aged 5 to 14 years, the prevalence increased and the YLDs decreased. Conclusion Dental caries remains a huge health burden in Western China. In contrast to the global and national data, the trend has increased rapidly over the past 25 years in this region. This work provides suggestions for the prevention and control for oral health in China with the policy of two-child.

COAGGREGATION AND COAGGREGATION INHIBITION BETWEEN PERIO-PATHOGENIC AND CARIOGENIC BACTERIA

Objective To screen the coaggregating pairs between perio-pathogenic and cariogenic bacteria and to investigate the susceptibility of these coaggregations to inhibitors. Methods 4 strains of perio-pathogenic bacteria, Fusobacterium nuleatum （Fn） ATCC 10953, Actinobacilllus actinomycetem comitans （Aa） Y4, Porphyromonas gingivalis （Pg） ATCC 33277,Prevotella intermedia （Pi） ATCC 25261 and 4 strains of cariogenic bacteria, Streptococcus mutans （Sm） lngbritt, Streptococcus sanguis （Ss） 34, Actinomyces viscosus （ Av） 19246 and Lactobacillus acidophilus （La） ATCC 4356 were used to determine the coaggregating degrees of various combinations of the above bacteria by a visual assay and a turbidimetric assay. Then more than ＋ 2 （ or 20% ） coaggregation degrees＇ pairs were used to investigate the inhibitory effect of lactose and arginine and to identify the minimum of their coaggregation-inhibitory concentration. Results The coaggregation degrees of Fn-Av, Pg-Av, Fn-Sm, Fn-Ss, Fn-La and Pg-Ss pairs were higher than ＋ 2 （ 20% ）. 3.0 - 6.0mmol/L of arginine were considerably effective to the above pairs except Fn-Av pair and the disaggregation degrees were 49% - 92%. The maximum of their disaggregation degree to Fn-Av pair was just 18%. 120 - 300mmol/L of lactose were significantly effective to Pg-Ss pair, the disaggregation degrees were 57% - 91%. They partially inhibited Pg-Av pair and were almost ineffective to FnG^＋pairs. Conclusion The coaggregations between perio-pathogenic and cariogenic bacteria are highly specific. Most of them are relatively sensitive to arginine.