[Table/Fig-4]:

Landmark studies.

Author	Year	Place	Observation	Conclusion
Marshall-Day and Shourie [8]	1949	Punjab Province	568 people from 9 to 60 years of age	Periodontosis present in about 35% of the cases.
Mehta et al., [9]	1953	Bombay and Ratnagiri district	2219 male subjects of low socioeconomic level in the age group 19-55 years	Periodontal disease is very high among this population.
Sanjana MK and Mehta FS [10]	1956	Bombay	Residents including 1,445 population in age group of 16-50 years	83.2% generalized periodontal disease.
S. Ramfjord [11]	1957-1963(as a part of WHO surveys)	Bombay and Bassein (present ’Vasai’) region	1,677 urban and rural population using Ramfjord periodontal disease index	Prevalence of periodontal disease was close to 100% and starts after age 15; and at 17 years, 10% of Indian boys had periodontitis.
Greene JC [12]	1960 (in parallel to WHO surveys with the aid of U.S. public health service	Bombay and Bassein (Vasai) region	1,676 urban plus rural population using Russells’ periodontal index	97% of the 11-17 year-old persons examined, had high prevalence of periodontal disease.
S. Rao and S. Tewani [13]	1968	Bombay	1,200 males and females	6.83% population were suffering from periodontosis.
Anil S and Hari S [14]	1990	Trivandrum (Kerala)	2756 subjects	36 % population was having periodontal disease.