All About The Jaw Bone

Author: Dr. Sarah Mischo, DMD

October has officially arrived, and it’s the time of year when you may drive through your neighborhood and see a friendly pumpkin, a large spider web, or a couple of skeletons saying “hi”. Seeing the Halloween decorations in my neighborhood got me thinking about bones–more specifically, about the jaw bone. The upper jaw bone is called the maxilla, and the lower jaw bone is called the mandible, and these two bones are the solid anchoring point for every tooth in your mouth. But did you know that not all bones are created equal? Within the maxilla and mandible, there are actually four distinct types of bone that are different primarily in their density. The type and density of bone plays a large role in how long and successful a dental implant will be if it is placed within that area.

-Type 1 bone is homogeneous compact bone.  You can think of this bone as “oak wood” This type of bone is very hard and dense.

-Type 2 bone is a thick layer of compact bone surrounded by a dense layer of more porous, trabecular bone. This type of bone is comparable to pine wood.

-Type 3 bone is a thin layer of cortical bone that is surrounded by dense trabecular bone. This type of bone is softer and weaker and can be compared to balsa wood.

-Type 4 bone is a thin layer of cortical bone surrounded by a low-density trabecular bone. This type of bone is much less dense than the first three types and can be compared to styrofoam in our analogy.

 The mandible usually contains more dense bone compared to the maxilla. As you move toward the back of the jaw bone, the density starts to decrease and the porosity of the bone increases. Type 1 bone is found mostly in the anterior mandible, and most of the rest of the mandible is made up of type 2 bone. The anterior maxilla is usually made of type 3 bone, and type 4 bone is usually found in the posterior maxilla.

If you are thinking about getting a dental implant, you may have heard us say we need to take a CBCT to see the quantity and quality of bone to determine if the site is a good candidate for an implant. The CBCT is a 3D image that helps us evaluate the density of bone in a given area of the jaw and allows us to plan where an implant would have the greatest likelihood of success. While implants can be successful in any type of bone, Type 1 and Type 2 bone usually provide the most stable initial anchor point for a dental implant and the best chance at long-term success. But don’t worry, even if you’re hoping to get an implant in one of the areas that usually contains lower-density bone, there are augmentation procedures that can strengthen the bone in this area, and additional surgical techniques that can often make an implant viable even in low-density bone locations!

I hope your Halloween is spooky and spectacular and hope you now have at least one topic to break the ice with any skeletons you may run into!