When it comes to bears in Alaska, there's alot of different issues. Sure, we're used to sharing the trail with both blackies and browns. Most of the time in Anchorage they are pretty good neighbors. But sometimes they aren't. A dog isn't going to deter a grumpy bear, although it might alert the bear to human presence in time for the bear to take off before the human is in sight. But a bear guarding a kill isn't going to care whether there is a dog, a wolf, a coyote, or a 15 year old on a mountain bike, they are going to be aggressive. We don't hike with dogs to deter bears, we hike with dogs because we like to hike with dogs. Maybe because bears are just a "normal" part of the scenery they all seem to play pretty well together in the sandbox. But if you were to take a dog into an area that it is not familiar, with the potential of meeting a bear, with which it is not familiar, the dog might get itself hurt.
You really can't compare bear behavior in Alaska to bear behavior anywhere else. I've said this before and I will say it again. You can't even compare bear in Anchorage to bear in Kenai or Kodiak or in the Brooks Range. Bear behavior is based on how well it is thriving and how hungry it is and how plentiful food is at any given time. When food is late in arriving we have alot of incidents with bears. When berries and fish arrive on time, fewer incidents. You can not make assumptions about bear safety from reading a forum. We learn to hike with all of our senses - you have to be alert at ALL times. I can't tell you how many times I've had a black dog run up behind me and scare the crap out of me because out of the corner of my eye he looks like a juvy blackie, and they can be more dangerous than you'd think (like any teenager, they tend to act like they think they are invulnerable). You rarely walk through the woods without seeing wildlife because you have to keep your senses on alert at all times. We behave differently because of the bears, but it is so innate that when we talk about it we sound almost flip about the dangers. But believe me, most of us who hike in AK, with or without dogs, take something else as deterrent (bear spray or gun depending on one's feelings on the matter).
MNS (who is not currently in AK, but still looks for bears!)
YMMV. Viewer discretion is advised.