Comprehensive Health History: Are You Doing a Thorough Review?

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As dental hygienists, we are all educated on the importance of obtaining a thorough health history on our patients. Oral health can affect overall health and vice versa. A thorough health history also allows us to minimize risks associated with treating our patients and can help prepare and possibly predict, for a medical emergency. However, with appointment times being shortened and with the constant struggle of staying on schedule, reviewing a patient’s health history can sometimes be rushed through. This is a dangerous habit of falling into. So I’d like to give a bit of a reminder and overview of a comprehensive health history and some medical conditions which can alter dental treatment.

Be Thorough, Every Appointment, with Every Patient

New patients should complete a health history, and this health history should be reviewed at every dental appointment. When reviewing medical history, blanket statements like, “Any changes in your health?” don’t tend to get us the answers we need. Many patients will simply reply with, “No.”

Better, more specific, questions are: Have you been hospitalized or gone to the emergency room recently – or in the past six months (or however long it’s been since you’ve seen them)? Are you currently under the care of a doctor? If so, what for (diabetes, high blood pressure, etc.)? Instead of asking, “Any changes in your medications?” Ask an open-ended question, “What medications are you currently taking?” Then compare what they state to what’s listed in their chart. This is always a good time to remind patients, especially those who are on multiple medications, to keep an updated list on them in their purse, wallet, or in their phone, at all times.

Be aware that even with open-ended questions, patients can still forget to tell you something. I had a periodontally-involved patient who, despite my specific and open-ended questions, stated he had no had changes to his medical history, answered, “No,” to my question of if he’d been to the emergency room or hospitalized recently. He also listed the same medications he was taking as he did at his previous appointment.

However, a couple of hours after his appointment, he called the office because he forgot to tell me he had a heart attack a week before, asking what he should do. I told him to call his cardiologist immediately as I had no idea the extent of the damage to his heart and how dental treatment could affect him adversely. Because of this experience, when writing chart notes, I don’t write, “Reviewed medical history: no changes,” I now write, “Reviewed medical history: patient reports no changes. That experience really opened my eyes on just how fast patients forget, and how patients don’t understand what’s going on systemically can alter dental treatment, so they simply don’t disclose.

I’ve had a few patients who are annoyed at why we need to know their medical history. Be prepared with an answer. I explain the oral health and overall health connection, giving examples, and that many medications can cause oral side effects (xerostomia which can lead to caries, etc.) and may require modifications in their treatment (anesthesia with no epi, for instance). Further, I explain that all of my medical questions are to keep them as safe as possible during my treatment of them.

Because the health history is a legal document, it’s also recommended that the healthcare professional and the patient sign the health history after review. There should be an area for this on the health history form. A disclaimer should be included on the health history stating that the patient does not hold the dentist and other dental team members responsible for any errors and/or omissions of health information the patient may have made when filling out the form. If you are a digital office, a time and date stamp should be updated to fill this requirement. Further, if there’s a mistake on a written form, use ink and cross it out with one line and you and the patient should initial it. Don’t use White-Out correction fluid or correction tape.

While we review a patient’s medical history at every appointment, there’s no law stating a specific timeframe of how often a new health history should be filled out by a patient. However, general consensus and best practices say, it should be done every 2-3 years. I have read in the past that a written health history should be kept after scanning it into the computer system; however, many offices will shred the written health history after it is scanned. I contacted the Board of Dentistry in my state. The Oregon Board of Dentistry stated, “If an office scans the paper records into the electronic record, the paper record does not have to be maintained.” This may vary state to state, so it’s best to do your due diligence and check with your state Board for the proper and legal protocol. If your office isn’t digital yet, keep all “old” health histories.

Medical Conditions which can Alter Dental Treatment

A comprehensive health history alerts us to our at-risk patients. While there are many medical conditions which can alter dental treatment, I’d like to highlight a few of those conditions:


If a patient is allergic to an antibiotic, we need to know just in case one needs to be prescribed; same goes for pain relievers, like codeine. Latex is another allergy we must know about in a dental office. If your office isn’t fully latex-free, schedule an allergic patient as the first patient of the day before the powders from other treatment aren’t in the air.

A patient may not realize they have a latex allergy. A good question to ask a patient with a suspected latex allergy is if the patient has ever experienced nausea, vomiting or stomach cramps after eating bananas, kiwis, water chestnuts, avocados, or tomatoes, as they contain a similar chemical to those in natural rubber latex. Patients with a history of reactions, including oral itching, to figs, apples, carrots, celery, melons, potatoes, papayas and pitted fruits, like cherries and peaches, are at increased risk of developing latex allergies. Further, Patients with spina bifida and urogenital abnormalities are prone to latex allergies.

It is wise to know the contents of the products you use in your office. Some fluoride varnishes contain tree nut oil or gluten; prophy paste can contain gluten; topical anesthesia can contain fruit flavorings; Recaldent (MI Paste) contains casein – a milk protein (some toothpaste and Trident gum contains this too); and dental cements contain eugenol from the oil of cloves. I read an article in another publication which stated, nitrous oxide – while it doesn’t contain eggs – contains a substance that is molecularly similar to eggs and reactions have been reported, however, in researching, I couldn’t find any research supporting this claim.


Diabetic patients should be scheduled in the morning because endogenous cortisol levels are generally higher at this time (cortisol increases blood sugar levels). If this is not feasible, schedule the appointment after the patient has eaten. When reviewing the medical history, be sure to ask questions regarding A1C levels (< 7%), when A1C was checked last, how often glucose levels are checked including the last reading (fasting 70-130 mg/dL, after meals < 180 mg/dL), when the last time the patient ate was, if the patient took medication on time today and if the patient has experienced low blood sugar levels in the past. Don’t be afraid to contact the patient’s physician or reappoint if needed, as it’s in the patient’s best interest to avoid a medical emergency, such as hypoglycemia.

Kidney Disease

If a patient marks kidney disease on their health history, it is important to discern the extent. Do they have acute renal failure, chronic renal failure, or are they a transplant patient? Acute renal failure patients are not common for dental professionals to treat because renal function is restored (within hours or days) once the underlying cause has been resolved. The latter two are more likely for a dental professional to treat.

Chronic renal failure patients may be undergoing dialysis if conservative management does not prevent or correct renal function. These patients are best treated the day after dialysis as platelet function will be at an optimum level, and the heparin will have had a chance to wear off (get a recent blood count/INR number before dental treatment). Blood pressure should not be taken on the arm used for dialysis access. A transplant patient should avoid elective dental treatment for six months after their transplant. Kidney disease and kidney transplant patients may require premed (avoid tetracycline), may need an extra dose of corticosteroids or other modification of medication (avoid aspirin and NSAIDs), among other considerations (use of an ultrasonic scaler may be contraindicated due to respiratory risk of inhalation and resulting bacteremia and use fluoride with caution). A consultation with a written release from the patient’s renal physician is recommended.

Heart Problems

If a patient marks heart problems in their health history, again, it is our job to discern the extent and control-level of the disease. Heart problems can encompass many conditions such as rheumatic heart disease, congenital heart defects, coronary heart disease, heart failure, hypertension, angina, heart murmur, mitral valve prolapse, pacemaker, or history of myocardial infarction. Further, the patient could have stents or artificial heart valves. Point being, a check next to heart problems requires a thorough conversation with the patient to keep them safe in your chair. Some of these conditions require antibiotic premedication. These include:

  • A prosthetic cardiac valve or prosthetic material used for valve repair
  • History of infective endocarditis
  • A cardiac transplant that develops cardiac valvulopathy
  • Congenital heart diseases including: an unrepaired cyanotic congenital heart disease, including palliative shunts and conduits; a completely repaired congenital heart defect with prosthetic material or device, whether placed by surgery or by catheter intervention, during the first six months after the procedure; any repaired congenital heart defect with residual defect at the site of a prosthetic patch or prosthetic device (that inhibit endothelialization)

Sometimes patients simply forget to take their premed an hour before their dental appointment. The American Heart Association (AHA) guidelines for infective endocarditis (and ADA) state, “If the dosage of antibiotic is inadvertently not administered before the procedure, the dosage may be administered up to 2 hours after the procedure.” What if a patient is already taking an antibiotic for another condition and needs to premed? The AHA (and ADA) recommends that the dentist select a different class of antibiotic than the one that the patient is already taking. For instance, if the patient is taking amoxicillin, the dentist should select clindamycin, azithromycin, or clarithromycin.

Beyond the need for premed, there are other factors to ask the patient. For instance, if they are taking warfarin, or an anti-coagulant that requires physician monitoring, have they recently seen their physician and had their INR numbers checked? If the patient experiences angina, a clinician would want to ask what induces an episode – physical strain, stress? It is important to have the patient bring angina medication with them to a dental appointment and have it at the ready in case of a medical emergency. Local anesthesia with epi may need to be used cautiously (i.e., limit two carps Lidocaine with 1:100,000 epi) or even no epi at all with patients who have uncontrolled hypertension, angina, history of myocardial infarction, or arrhythmias.

Patients with a recent history of myocardial infarction may need to postpone dental treatment. The first month after an MI, death can occur from sudden cardiac death, heart failure, mechanical cardiac complications, or another MI event. This time can be extended depending on many risk factors or depending on the extent of the damage to the heart. Contacting a patient’s physician for a dental treatment release, in writing and kept in the patient’s chart, is recommended.

Patients with hypertension may not be controlled just because they wrote down that they are taking medication. Simply put, many patients forget to take their prescribed medications regularly. Taking a patient’s blood pressure before dental treatment has become law in some states. Whether it’s the law in your state or not, taking blood pressure is best practice. I’ve heard many stories of blood pressure being taken at a dental appointment, the reading being surprisingly high, dental treatment postponed and the patient referred to their physician or the emergency room, and all of this potentially saving their life.

I’ve also heard stories of the opposite outcome; blood pressure being taken at a dental appointment, the reading being surprising high, treatment was postponed, and the patient referred to their physician or the emergency room; however, the patient doesn’t go and has a myocardial infarction days later. Make sure your office has a protocol for when a patient should be referred due to high blood pressure. From the doctor to the dental hygienist to the dental assistant, everyone needs to be on the same page regarding when to refer patients due to medical necessity.

In 2017, the American College of Cardiology (ACC) and the American Heart Association (AHA), along with 9 other health professional organizations, reviewed over 900 published studies and announced an update to the 2003 blood pressure guidelines. These guidelines state the uncontrolled blood pressure (180/110 mm Hg) or greater is classified as a minor risk condition when it comes surgical procedures, meaning most dentistry is considered safe up to these levels. However, stated also, is blood pressure should be brought under control before any surgery is performed, and because many dental procedures are elective, the general recommendation is to defer care at a blood pressure of 180/110 mm Hg or higher.

Category Systolic Diastolic
Normal <120 and <80
Elevated 120-129 and <80
Stage I hypertension 130-139 or 80-89
Stage II hypertension ≥140 or ≥90
Hypertensive crisis >180 and/or >120


Some patients may question why you need to take their blood pressure. Again, be ready with an explanation. Hypertension can be a sign of a blockage which could lead to myocardial infarction. It can also cause hypertrophy of the left ventricle which can lead to congestive heart failure, myocardial ischemia, arrhythmias, and sudden death. Hypertension can also lead to kidney disease and increases the risk of stroke.


Before treating a patient undergoing chemotherapy, the patient’s oncologist needs to be consulted for clearance. The patient may be immunosuppressed due to low white blood cell/neutrophil count, and dental treatment may need to be postponed. Patients shouldn’t be seen with a neutrophil count less than 1,000/mm3. Antibiotic prophylaxis may be needed if the patient has a central venous catheter. Cancer patients with a port may be on anticoagulants which can cause excess bleeding and be a risk for infection. Invasive dental treatment should be postponed if platelet count is less than 75,000/mm3 or abnormal clotting factors are present.

When consulting the patient’s oncologist some questions you may want to ask include:

-What is the complete blood count, including absolute neutrophil and platelet counts, of the patient?

-Does the patient have a central venous catheter, port, or any other chemotherapy drug delivery system placed?

-Based on the two previous questions, is it safe for the patient to receive dental treatment? Elective dental treatment or emergency treatment only? If yes, is antibiotic premedication indicated?

-Is the patient undergoing radiation therapy?

In a perfect world, cancer patients would be informed on the need to complete all dental treatment before cancer treatment begins. This includes eliminating sources of oral trauma, such as poor-fitting dentures, orthodontics, and other appliances. Even if they are informed, a cancer patient is often times overwhelmed with an influx of information in a short period of time, so the need to complete outstanding dental treatment may be forgotten. We must be their safety net and take the extra moment to look out for their health.

My father underwent two rounds of aggressive chemotherapy and radiation treatment. During this time, I read many online cancer patient forums. One thread I will never forget was a cancer patient’s experience at their dental office. For the patient’s safety, the dental office chose not treat the patient. However, this decision was not explained to the patient, according to the patient writing on this forum. The patient felt as though they were being treated as if they had the Plague. Of course, this is second-hand information, so I have no idea what was really said.

However, the fact remains that this patient left their dental office feeling this way. Educating patients in oral health is what we do; this education must extend on why we do the things we do such as postponing treatment or requiring premedication. We must ensure the patient understands that postponing treatment or an antibiotic is for their safety based on recommendations from their oncologist (or surgeon, physician, etc.). I encourage you to educate with compassion. Some cancer patients may be feeling defeated and going through emotions that some of us with no experience with cancer will ever understand.

These are only a few conditions that require considerations and possible alterations to dental treatment. There is a multitude of others; blood disorders, asthma, COPD, acute adrenal insufficiency, undergoing radiation treatment, and this list could go on. The point here is that a thorough health history is a must because of the many conditions which can alter treatment. Not only does a thorough health history give us the information to provide safe treatment to a patient and prepare us for a possible medical emergency, but it also allows us the opportunity to educate the patient on how their medical condition and/or the medications they take can affect their oral health. Even with the most comprehensive health history, we must remember that not all patients disclose everything. Whether it be embarrassment or forgetfulness, we must keep this in mind. A health history is a good guide, but still just that, a guide, so we must be as thorough as we can.

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SEE ALSO: Health History Update: How to keep from getting stuck in “the script”


  1. ACLS Certification Institute. (2016). Myocardial Infarction: Prognosis and Predictors of Mortality. Retrieved from
  2. American Dental Association: Mouth Healthy (2016). Cancer: Taking Care of Your Teeth During Treatment. Retrieved from:
  3. American College of Allergy, Asthma & Immunology. (2014). Latex Allergy. Retrieved from
  4. American Dental Association. (May 2016). Antibiotic Prophylaxis Prior to Dental Procedures. Retrieved from
  5. Cervero, A.J., Bagan, J.V., Soriano, Y.J., Roda, R.P. (Jul 2008) Dental Management in Renal Failure: Patients on Dialysis. Med Oral Patol Oral Cir Bucal, 13(7). Retrieved from
  6. Davidson, N.K., Moreland, P. (May 2013). Know Your Blood Glucose Target Range. Mayo Clinic. Retrieved from
  7. Fis, B. (Oct/Nov 2008). Avoiding Common Dental Allergens. Grapevine. Retrieved from
  8. Georgakopoulou, E.A., Achtari, M.D. (2011). Dental Management of Patients Before and After Renal Transplantation. Baltic Dental and Maxillofacial Journal, 13. Retrieved from
  9. Greenwood, M., Meechan, J.G., Bryant, D.G. (Aug 2003). General Medicine and Surgery for Dental Practitioners Part 7: Renal Disorders. British Dental Journal, 195. Retrieved from
  10.  Lalla, R.V., D’Ambrosio, J.A. (Oct 2001). Dental Management Considerations for the Patient with Diabetes Mellitus. JADA, 132. Retrieved from
  11. Little J.W., Falace D., Miller C., et al. Dental Management of the Medically Compromised Patient. 6th Edition. St. Louis, MO: Mosby; 2002.
  12. Miller, C.S., Glick, M., Rhodus, N.L. (2018). 2017 Hypertension Guidelines. JADA, 149(4): 229-231. Retrieved from
  13. National Institute of Dental and Craniofacial Research. (July 2014). Dental Provider’s Oncology Pocket Guide. Retrieved from
  14. Ramu, C., Padmanabhan, T.V. (Sept 2012). Indications of Antibiotic Prophylaxis in Dental Practice – Review. Asian Pacific Journal of Tropical Biomedicine, 2(9). Retrieved from
  15. Reddy, S. (Jan 1998). Latex Allergy. American Family Physician, 1;57(1). Retrieved from
  16. Wilkins, E. (2009). Clinical Practice of the Dental Hygienist, 10th ed. Philadelphia: Lippincott Williams & Wilkins.
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Kara Vavrosky, RDHEP
Kara Vavrosky, RDHEP, is a co-founder and the chief content officer of Today’s RDH, an independent educational publishing company for dental hygienists, encompassing articles, a podcast, virtual continuing education events, and self-study continuing education. Today’s RDH was launched in 2018 after Kara built her social media presence with her largest following on her Facebook page, Dental Hygiene with Kara RDH, which was created in 2013. An Oregon Institute of Technology graduate, Kara has a deep passion for spreading knowledge about the importance of oral health and its association with systemic health. Kara’s passion extends to helping other hygienists understand current protocols and evidence-based research – all with the goal of lifting dental hygienists and the dental hygiene profession. Kara was recognized in 2020 as one of the Top 100 Women in Media for her entrepreneurship as a co-founder of Today’s RDH. In 2022, she was recognized by the American Dental Hygienists’ Association for their Standout Seven Award in the Entrepreneur category. Kara lives in Vancouver, Washington, just outside Portland, Oregon, with her husband, Ben, and their four Chihuahuas. When she’s not working, Kara loves riding the Oregon Dunes on her quad, spoiling her Chihuahuas, and spending time with her close-knit family.