I usually start them in the woods between 8 months and a year depending on the time of year. As far as canines go...I don't think it matters much if they have them or not when it comes to catching. The canines weren't designed for holding...if I'm not mistaken, they were designed for tearing. The 2 bulldogs in this pic have full mouth bites...it wasn't the canines that were responsible for catching this hog.
Scott is right, the canines are not the teeth that a dog relies on to hold however like shotgun said the canines are not fully set and you can risk damaging the dogs gums/mouth. I wouldnt be worrying about the dog holding a hog as much as i would be worried about long term damage to his mouth.