Every time I see a patient, old or new, I ask about their general health. I'm sure that sometimes it seems as though I'm just being polite, but taking a complete medical history is one of the most vital parts of a dental appointment. Occasionally a patient will flat out ask, "Why do you need to know that?", or will give a vague answer perhaps in the hope I will gloss over the details, but the reality is that while someone is under a dentist's care that dentist is responsible for how dental treatment will impact their overall health, and how their overall health will impact dental treatment. As the old song goes, the hip bone's connected to the leg bone, and the mouth is part of the whole system of the body with many complex interactions. It's so complicated that it would be impossible for me to cover in a single, easy-to-read article, but here are some of the reasons it's important to give your dentist a complete and detailed medical history.
Medications
Pills, capsules, syrups, suspensions, injections, infusions, puffers, creams, ointments, vitamins, supplements, herbal remedies, troches, lozenges, suppositories, pessaries, patches, devices like CPAP, therapeutic diet changes... "Medication" isn't limited to prescription pills. From a moral and legal standpoint, it's not up to the patient to decide what's relevant and what's not. If you inform your dentist of everything you're taking they can assess the risk for you and avoid any nasty surprises. Some things aren't obvious, for example daily fish oil over a certain dose increases the risk of post-extraction bleeding. Turmeric supplements can have this effect as well. Taking both? Plus, aspirin daily on your doctor's advice to prevent a heart attack? The risk is increased even higher. Having 6-monthly injections for osteoporosis? There's a small chance your bone won't heal properly after an extraction. Taking anti-depressants? Some will interact with the local anaesthetic dentists use, some will cause reduced saliva flow which puts you at increased risk of tooth decay. You're not expected to understand all the ins and outs of your medications, but your dentist is. If you're on a complicated regime, bring in a written list or get a printout from your pharmacist/GP.
Operations
Exactly like medications, there's some things that seem obvious and some that really aren't. List everything and let your dentist decide. One of the big ones is joint replacement surgery. In the first 6 months after surgery there's an increased risk of the joint becoming infected from bacteria entering the bloodstream via the mouth, for example during a scale and clean. Ever had heart surgery? Some procedures carry the same risk of infection. If your dentist knows, they can take appropriate precautions to minimise the risk. Radiotherapy falls into this category as well, as radiotherapy to the head/neck area has serious consequences for healing and saliva flow.
Medical conditions
"I had a heart attack 2 years ago, but I'm fine now". I'm not kidding, I've heard this in the casual conversation with a patient during an appointment after I thought I'd already taken a detailed medical history. This example led me to ask about preventative medication, (this patient was taking daily aspirin which increases bleeding risk, "but it's just from the supermarket"), and to change my choice of local anaesthetic in order to put as little strain on the heart as possible. Have Type II Diabetes but controlling it with diet rather than medicine? You're still at increased risk of infection, including periodontitis which is a gum disease that can result in tooth loss. Suffer from heartburn or indigestion? The acid from your stomach could be damaging your teeth. Include in your list of medical conditions any problems that you're still having investigated by another health professional.
Allergies and adverse reactions
Even if you just get hay fever during spring, write it down. It tells your dentist that you're prone to allergies. Latex allergy is an obvious one to tell your dentist about, since we primarily use latex gloves. But did you ever think a milk protein allergy would be relevant? We use some products that contain the milk protein casein, so it's important to differentiate between lactose intolerance and true dairy allergy. I once had a patient react to a common product use for taking impressions because he had an undisclosed allergy to titanium dioxide, a white pigment used widely in cosmetic and pharmaceutical products. He didn't mention it because he thought it was only found in sunscreen. True allergy to local anaesthetic is extremely rare, but it's common for patients to reports an "allergy" to the adrenaline found in common local anaesthetic products. If you let your dentist know they can tailor the products used to make your treatment safe and comfortable.
Confidentiality
Your dentist is bound by the same confidentiality your doctor is. They are not allowed to discuss any information with a third party without your consent unless there is legitimate concern for the immediate safety of yourself or someone else. This definitely includes your partner, family, or friends who attend the same practice. We understand that some medical things are hard to talk about or embarrassing, but a good dentist will maintain professionalism as it's in everyone's best interest to have all the information. A good dentist will not treat you any differently if you have a communicable disease such as viral hepatitis or HIV, other than to make sure they're looking after your health. A good dentist will pass no judgement on the use of medication like Viagra for erectile dysfunction but will know to be careful about potential life-threatening medication interactions. A good dentist will not judge you for use of illegal drugs, and will absolutely not call the police, but can help counsel you about managing the dental implications.
I could write pages on this topic, it's something I consider every single day in practice. This is by no means an exhaustive list of the potential implications of your general health interacting with the world of dentistry. So use your dentist's expertise, give a full and detailed medical history that allows your dentist to have the entire picture, so they can make the best choices for your treatment. It's what you're paying for!