I'm curious as to which would lead to more tooth decay, a few meals a day or frequent snacks a day?

Bacteria: Doesn't matter how many times a day you eat. What matters is bacteria. Bacteria convert sugars/starches int acids that make holes in teeth. Bacteria produce digestive enzymes that digest your gums. Clean the bacteria off 2x/day (including between the teeth bacteria) and you should be ok. Ask your dentist/hygienist for oral hygiene instructions that work for you.

Tooth decay: The frequency of meals does not cause decay. Decay is the result of poor food choices (foods and snacks that are high in sugar and/ or stick to the teeth), too much soda or drinks high in sugar, and poor oral hygiene. Watch your diet. Brush and floss "thoroughly" twice a day, and especially at bedtime.

Frequency of sugars: Frequent snacks that have high sugar and acid content would be very destructive your teeth.

No doubt !!: Frequency provides bacteria with sugar to make acids and toxins for a much longer sustained level. Avoid sugary snacks and always at least rinse, swish, spit or swallow whenever you can afterwards to decrease amount of sugar available. Best to develop habit of lowering sugar intake -- you will feel better all over after about 2 weeks. Good luck.