Aim: To identify risk indicators associated with tooth loss and periodontitis in treated patients responsible for arranging supportive periodontal care. Materials and Methods: Ninety seven Chinese subjects (34-77 years) who showed favourable responses to periodontal therapy provided in a teaching hospital 5-12 years previously were recalled. They were advised to seek regular supportive periodontal care on discharge. Background information, general health status, smoking, oral hygiene habits, follow-up dental care, tooth loss, and periodontal parameters were investigated. Multiple regression analysis was performed. Results: Two hundred fifty six teeth had been lost; 195 due to self-reported periodontal reasons. Up to 26.8% sites were with pockets 6mm. Positive correlations were found between total/periodontal tooth loss and i) smoking-packyears, ii) time spent on oral hygiene, iii) years since therapy's conclusion, iv) age; and negative correlations with v) interdental brush use, and vi) education levels. Tooth loss by arch was correlated with removable partial denture wearing in that arch. Percentage sites with pockets 6mm was significantly negatively correlated with percentage sites without bleeding on probing. Conclusions: Smokers, more elderly patients, removable partial denture wearers, patients with lower education levels or not using interdental brushes ought to be targeted for clinic-based supportive periodontal care.

SUMMARY Background

The aim of this study was to investigate the microbiota of noncaries associated supra-gingival plaque (SGP) microbiology in Sjögren's syndrome (SS). Stimulated whole saliva (SWS) and full-mouth SGP on intact tooth surfaces were collected from 26 primary (p) SS, 27 secondary (s) SS, and 29 control subjects for selective culture of lactobacilli, mutans streptococci, and aerobic and facultatively anaerobic gram-negative rods (AGNR). Predominant cultivable anaerobes from SGP of 11 randomly selected subjects from each group were investigated. Clinical and sialometric data were also collected. SS sufferers had significantly lower SWS flow rate and higher mean DMFT (decayed, missing, filled teeth), while pSS subjects also had lower SWS pH and fewer standing teeth. Lactobacillus acidophilus levels in SWS (P = 0.012) and SGP (P < 0.0001) were significantly elevated in pSS sufferers compared with sSS individuals and controls. AGNR isolation was uncommon. SS sufferers had significantly lower proportion of gram-negative species (P = 0.047). Non-oral species were isolated in greater proportions from pSS SGP (P = 0.007). Subjects with pSS harbored increased levels of L. acidophilus and non-oral species, while SS sufferers generally had lower proportions of gram-negative species. The microbial composition of noncaries associated SGP indicates a potential source of increased caries risk in SS.

Despite good oral hygiene and regular dental check-ups, the oral health of southern Chinese with primary SS was significantly compromised compared with secondary SS cases and controls, most probably due to the combined effect of impaired salivary gland function and poorer saliva buffer capacity.

In Hong Kong, approximately one million people are affected by severe road traffic noise. It is crucial to estimate the vertical distribution of traffic noise levels at different levels in high-rise buildings during the planning and design stages for new residential buildings. The Calculation of Road Traffic Noise (CRTN) has been adopted in Hong Kong to estimate traffic noise from the road. However, there have been criticisms of the CRTN model’s accuracy and suitability for predicting road traffic noise in Hong Kong. This study examines and evaluates the accuracy of the CRTN method in predicting the vertical distribution of traffic noise level LA10 at different floor levels of a 20-storey residential building in Hong Kong. Also, measurements have been conducted of the traffic noise levels at each floor level of the building. Both the predicted and measured LA10 show a similar trend: the higher the floor level, the lower the traffic noise levels. However, the predicted LA10 at the building façade has a tendency of overestimation, especially at the higher floor levels, with a mean difference of +2.0 dBA between the predicted and measured results. A correlation coefficient (R2) of 0.9331 between the predicted and the measured LA10 indicates that the predicted levels correlate closely with the measured levels. The CRTN is therefore a useful tool in predicting traffic noise levels at different floor levels during the building planning stage. Practical application: This study provides an evaluation of the accuracy of the CRTN method in predicting the vertical distribution of traffic noise level at different floor levels of a residential building. It suggests that the CRTN is a useful tool in predicting traffic noise levels at different floor levels during the building planning stage.