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. Author manuscript; available in PMC: 2014 Dec 1.
Published in final edited form as: J Dent. 2013 Apr 18;41(12):1148–1163. doi: 10.1016/j.jdent.2013.04.006

Table 2.

A summary of key characteristics of studies in the review (n = 60)

Study characteristics Frequencies Percentages
Type of research
Epidemiology 32 53
Outcomes 16 27
Health services 10 17
Other 2 3
Research design
Cross-sectional 25 42
Cohort 20 33
Case control 8 13
Longitudinal 5 8
Quasi-experimental 1 2
Randomized control trial 1 2
Sample size
1 – 999 35 57
1000 – 5000 11 19
5001 – 99,999 11 19
100,000 + 3 5
Follow-up period
0 – 2 years 26 43
3 – 9 years 23 38
10 + years 11 19
Patient care setting
Dental school clinics 15 25
Dental HMOs 11 19
VA medical centers 11 19
Public dental health centers/nursing home 10 17
Other hospitals/clinics 7 10
Private dental practices 6 10
Research setting
VA medical centers 9 15
Kaiser Permanente 9 15
Dental insurance groups 3 5
Other 39 65