The sample size was calculated to give a power of 80.0% and a standard error of 5.0%. Two controls were individually matched for each case. The odds ratio (OR) used was set at 2.0 and the probability of dental caries experience among cases was set at 63.7% . The probability of traumatic dental injuries among cases was set at 16.0%  and the probability of malocclusion among cases was set at 57.2% . The sample size was calculated for each oral condition. The probability of traumatic dental injuries among cases was used due to their lower prevalence, indicating the need for a larger sample. The minimum sample size to satisfy the requirements was 182 cases and 364 controls.