Can you give any guess as to what is causing my horizontal bone loss in parts of my mouth? non-smoker, per visits 4 x's year, good oral hygiene.

See a Periodontist: Perhaps you already see a periodontist. Sometimes there is just a generalized loss of bone. If its horizontal bone loss without pockets & not accompanied by gum inflammation, bleeding gums, tooth mobilities, or increasing sites/places plaque can accumulate, it might not be anything to be concerned about. Do you grind your teeth?

Periodontal disease: The good news is that periodontal disease is preventable, but unfortunately, some people are more susceptible than others, due to a genetic predisposition. The key to prevention is keeping the 'pocket' (the region between the gum and the tooth) as clean as possible. In my practice, I have found that diligent patients like yourself, can benefit tremendously by using a water jet device, daily.

Periodontal disease: There are many factors that contribute to bone loss around your teeth for example: smoking diabetes poor oral hygiene stress heredity crooked teeth underlying immuno-deficiencies fillings that are defective taking medications that cause dry mouth bridges that don't fit properly female hormonal changes.

Also: The systemic condition of osteoporosis, as well as diabetes. Both will increase the incidence of periodontal bone loss.

Occlusion: See a prosthodontist to evaluate your bite and overall occlusion. Ask about fremitus. Also see about clenching and grinding. How do we loosen a fencepost ? We rock it back and forth. Can loosen a tooth and lose bone by the same type of rocking forces. Good luck.