Not always. It’s been years since I’ve been in residency and screened/interview applicants.
We always placed the most highest emphasis on academics.
But with the sheer volume of applicants - you will find those with both. Those with good academics and those with a prelim year.
Plenty of dental students with strong stats will match to a 4 year program.
I’m living proof. I got in the first round at my top matched program. It’s all dependent on the individual applicant.