Past the Precipice? Projected Coral Habitability Under Global Heating.

Coral reefs are rapidly declining due to local environmental degradation and global climate change. In particular, corals are vulnerable to ocean heating. Anomalously hot sea surface temperatures (SSTs) create conditions for severe bleaching or direct thermal death. We use SST observations and CMIP6 model SST to project thermal conditions at reef locations at a resolution of 1 km, a 16-fold improvement over prior studies, under four climate emissions scenarios. We use a novel statistical downscaling method which is significantly more skillful than the standard method, especially at near-coastal pixels where many reefs are found. For each location we present projections of thermal departure (TD, the date after which a location with steadily increasing heat exceeds a given thermal metric) for severe bleaching recurs every 5 years (TD5Y) and every 10 years (TD10Y), accounting for a range of post-bleaching reef recovery/degradation. As of 2021, we find that over 91% and 79% of 1 km2 reefs have exceeded TD10Y and TD5Y, respectively, suggesting that widespread long-term coral degradation is no longer avoidable. We project 99% of 1 km2 reefs to exceed TD5Y by 2034, 2036, and 2040 under SSP5-8.5, SSP3-7.0, and SSP2-4.5 respectively. We project that 2%-5% of reef locations remain below TD5Y at 1.5°C of mean global heating, but 0% remain at 2.0°C. These results demonstrate the importance of further improving ecological projection capacity for climate-vulnerable marine and terrestrial species and ecosystems, including identifying refugia and guiding conservation efforts. Ultimately, saving coral reefs will require rapidly reducing and eliminating greenhouse gas emissions.

Socio-demographic risk indicators for tooth mortality in rural Sri Lankans.

To explore the socio-demographic factors associated with tooth loss in rural inhabitants of Sri Lanka, a random sample of 2178 males aged 20-60 years was selected using multi-stage cluster sampling procedure. The number of missing and present teeth was recorded excluding third molars and the subjects were interviewed to elicit socio-demographic information as well as oral hygiene and tobacco consumption habits. The mean number of teeth lost in the sample was 5.17 +/- 5.43. Tooth loss increased significantly with age. Sinhalese had significantly fewer lost teeth (5.05 +/- 5.38) compared to Tamils (6.54 +/- 6.18) and Muslims (6.02 +/- 5.21) whereas education, income, oral hygiene practices and tobacco use were significantly associated with tooth loss in the bivariate analysis. A forward stepwise multiple regression analysis revealed that age, Muslim ethnicity and quantified tobacco use were positively associated with tooth loss while better socio-economic conditions and good oral hygiene habits were negatively linked with tooth mortality independent of other factors. Age, Muslim ethnicity, quantified tobacco use, income, education, brushing frequency and substance used for cleaning had significantly affected tooth loss. Quantified tobacco use and oral hygiene may be regarded as modifiable socio-demographic risk indicators associated with tooth mortality in Sri Lankans.

The economics of dental care in Sri Lanka. A profile of unqualified practitioners.

A study was carried out to determine the number and distribution of unqualified dental practitioners (UQP's), and to compare some aspects of their practice profile with those of general dental practitioners (GDP's) in the island. The results showed that there were probably as many UQP's as general dental practitioners and that 91 per cent of them provided dentures. The proportions performing extractions, fillings and scalings were 44, 58 and 38 per cent respectively. For most procedures their charges were roughly 30 per cent lower than those of general dental practitioners, although in the case of dentures they tended to charge nearly as much and sometimes more. A way of rationalizing the role of UQP's as de facto providers of dental care is suggested in the light of new information about this manpower type that is generally regarded as unlawful and therefore ignored.

Tooth mortality in plantation workers and residents in Sri Lanka.

The tooth mortality of 787 Sri Lanka tea plantation workers and residents aged between 15 and 85 yr was studied in terms of missing teeth as well as teeth requiring extraction for various reasons. The mean number of missing teeth per person was 6.7 +/- 9.0. A pattern relating actual tooth loss and tooth loss adjusted to take account of teeth needing extraction was observed. Such adjustment increased the mean number of missing teeth per person by about two teeth in most age groups. The age specific pattern of tooth loss was calculated. There was an abrupt increase in tooth mortality at the ages 45-54. The age specific tooth mortality for the Sri Lankan group was consistently less than for people in several Western countries. These trends were also apparent in the mortality pattern of individual tooth types. Although there was a tendency for more women to be edentulous, a significantly higher proportion of women than men had a full complement of teeth.

Views and expectations of sixth formers in Sri Lanka about dentistry and dental education.

Questionnaires were sent to thirty-one schools in various parts of Sri Lanka on the basis of schools from which the majority of dental students tend to enter. Responses were received from 1445 sixth formers in these schools. Various views common to a large proportion of the sample were identified, as well as differences between sub groups distinguished by sex, language, occupational background, and location of school. The results are intended to aid the teaching of subjects like community and preventive dentistry so as to avoid conflict with preconceived expectations of dentistry--based on traditional patterns of curative services--which students may bring with them into dental school. In this connection there were some hopeful signs of preventive orientation in the group studied.

Assessing the periodontal treatment needs of a population.

A longitudinal study was conducted on 106 patients attending a dental school and undergoing periodontal treatment, to assess the relationship between some commonly used periodontal indices and the time taken to treat periodontal disease. The data were analysed by assessing the times taken for examination, motivation, scaling and surgery for persons with ranges of indices such as D.I., C.I., O.H.I., G.P.I. (Ging), G.P.U. (Perio), G.P.I. (Comp) and P.I. A one-way analysis of variance was carried out to test the significance of trends. Next, a Spearman correlation coefficient was calculated for each index and its components and treatment time. The index which correlated most closely with examination time was the P.I. The G.P.I. (Ging) was the best predictor of motivation time and three indices, C.I., G.P.I. (Perio) and P.I. correlated significantly with scaling times. The P.I. and G.P.I. (Perio) correlated with surgery time. By converting periodontal indices into treatment times, planners can estimate with a fair degree of accuracy the time and resources required to carry out periodontal treatment for a population.

Assessing the periodontal treatment needs of a population.

A longitudinal study was conducted on 106 patients attending a dental school and undergoing periodontal treatment, to assess the relationship between some commonly used periodontal indices and the time taken to treat periodontal disease. The data were analysed by assessing the times taken for examination motivation, scaling and surgery for persons with ranges of indices such as D.I., C.I., O.H.I., G.P.I. (Ging), G.P.I. (Perio), G.P.I. (Comp) and P.I. A one-way analysis of variance was carried out to test the significance of trends. Next, a Spearman correlation coefficient was calculated for each index and its components and treatment time. The index which correlated most closely with examination time was the P.I. The G.P.I. (Ging) was the best predictor of motivation time and three indices, C.I., G.P.I. (Perio) and P.I. correlated significantly with scaling times. The P.I. and G.P.I. (Perio) correlated with surgery time. By converting periodontal indices into treatment times, planners can estimate with a fair degree of accuracy the time and resources required to carry out periodontal treatment for a population.