The results of this study correspond to 471 older adults, 47.5% of whom were male and 50.5%, female. Of the study population, 60.08% lived in an urban area, and central El Salvador was the most-represented region (21.4%). Over third of the participants (35.5%) did not have any schooling.
Most (71.34%) of the study population reported a low frequency of brushing, either brushing once or twice a day (52.02%) or not brushing at all (19.32%). Significant differences were found according to sex, age and region.
Consistent with the infrequency of brushing, 59.88% of the study population, according to the OHI-S, was categorized as having ’poor´ or ´very poor´ hygiene, similar to the results of related studies in India (63.68%) and Turkey (84.4%), in which most older adults had poor oral hygiene [15, 16]. Factors associated with poor hygiene could be a lack of knowledge of proper techniques, or low or lack of income to buy basic oral hygiene kits. Furthermore, the oral health status of older adults, although influenced by the aging process, also depends on their oral hygiene habits, the degree of physical disability, the assessment of oral health and their access to health services, among other factors [17].
The DMFT index in older adults, established according to ICDAS criteria, showed a total value of 23.38 in our country. A mean of 5.9.was found for the decayed component, corresponding to 6.85 for men and 5.0 for women, which reveals a significant differences between the sexes. This finding differs from the results of similar studies in New Zealand (0.5), Turkey (1.0), Spain (1.05), Colombia (1.16), Belgium (1.7), China (3.33) and France (3.7), where fewer caries experiences were reported in their active state [10, 16, 18–22]. The difference in the results of our study could be primarily attributed to the different criteria for establishing active caries between ICDAS, which includes initial carious lesions, and the WHO, which only considers cavities. Other factors that could be attributed to contributing to the difference could be the strength of the public health systems in developed countries, access to oral hygiene supplies, gastronomic differences in diets and the economic, cultural and educational levels of the populations surveyed in each country.
In this study, the DMFT index for the missing teeth component was 16.18 out of a total DMFT of 23.38, corresponding to 17.02 for women and15.32 for men. These results are similar to those of studies carried out in Colombia (17.7) (DMFT = 20.55), France (14.8) (DMFT = 20.55) and Belgium (14.8) (DMFT = 20.3), though they differ from those of studies from New Zealand (12) (DMFT = 24.2), Mexico (10) (DMFT = 18.3), Spain (10.70) (DMFT = 14.99), China (9.50) (DMFT = 13.33) and Turkey (8.62) (DMFT = 10.92). Although the missing teeth component is lower, it increases the total DMFT value, which shows that regardless of the country, the missing teeth component increases the total DMFT value. This is a constant finding in different studies of older adults, which provides evidence of a global public health problem that is yet to be solved [8, 10, 16, 18–24].
In accordance with the high prevalence of missing teeth, in the Salvadoran population, 90.23% of older adults required prosthetic rehabilitation to improve their quality of life and masticatory function, thus reducing the risk of malnutrition in Salvadoran older adults [11, 17].
The rate of edentulism in this study was 31.42%, which was similar to the rates observed in studies from South American countries, such as Brazil (46.4%) (N = 1750) and Colombia (32.87%) (N = 1180). However, the prevalence rate of total edentulism differed from those found in China (8.9%) (N = 4431), India (15.3%) (N = 6409), Ghana (2.9%) (N = 4093), Mexico (2.7%) (N = 19,155) and South Africa (8.7%) (N = 2985) [19, 24, 25].
The periodontal condition according to the CPITN indicated that 96.82% of the population had some degree of periodontal disease. More specifically, 35.46% had periodontal pockets of 4–6 + mm requiring specialized periodontal treatment, 23.57% had dental calculus where professional scaling was necessary and 6.37% had bleeding during probing where health education and prophylaxis were necessary. The results obtained were similar to those found in other countries that used the same index. For instance, a study in Turkey reported that 90% of the population evaluated required some type of periodontal treatment [16], while a study in Colombia reported that this related to 93.4% of the population evaluated [19].
The above data provide evidences that periodontal diseases are predominant among older adults in El Salvador, congruent with an infrequency of brushing and poor oral hygiene, which over time, favor the progression of the disease leading to dental mortality [26, 27].