of dental treatment access, and focused on a narrow range of
outcomes. By contrast, our study had a large sample size, detailed
exposure data, a consistent level of dental treatment across the
cohort, and investigation of a wide range of possible health
outcomes. The success of the follow-up process, accounting for
93% of the theoretically possible maximum person-time,
suggests that selection bias from loss to follow-up is not likely to
be a problem. Also, as noted in the Results, there were 8920
incomplete and 1716 missing records for people potentially in
the cohort. We think it highly unlikely that the distribution of