#26 What I Learned Today

Essentials of Clinical Practice

Today's lecture in ECP focused on how important it is for a dentist to take an accurate and complete medical history. A health assessment begins with a complete history taking of the patient, including:

• biographic/demographic/social/family history
• medical history (and current status)
  
• dental history (and current status)
• medication history

Of the most importance is the chief complaint (CC) of the patient. In other words, the reason the patient is seeking help. These can include simple lines such as, "I have cavities and I wanted them fixed" or "I want my smile to look better". Once you have the chief complaint, it is important to get the history of present illness (HPI). This is pretty much a narrative which explains how the patient got to be in his or her present condition. Many probing questions should be asked, especially focusing on the what/when/where/how/how long/intervention questions. The HPI can often give the dentist vital information which may ultimately affect diagnosis.

Finally, we began to look at different medical conditions and how they affect the oral cavity and how you would treat them. An example is dry mouth. It is often a side effect of taking specific medications. Consequently, you often see higher rates of decay as saliva helps remove the oral bacteria and remineralize enamel. Another example is cancer. IV Bisphosphonates are used to treat a number of common cancers, and have been shown to cause jaw bone necrosis in some patients.

Patients often come in with allergies. It's important to probe the specifics of the allergy, such as how the patient feels upon reaction, what happens (rash, swelling). It is important to determine if analphylaxis is a symptom of the allergy. Also, you also have to be aware of latex allergies in a dental office, since there are many latex-based products used including gloves and rubber dams.

Hypertension and its medications can also have side effects which are relevant in a dental setting. Orthostatic hypotension is one, which is low blood pressure occuring when the patient sits up. This can lead to dizziness or a fainting spell, which could cause the patient to fall and injure him or herself. You also tend to see dry mouth, angiodema of the facial region (swelling of the dermis and underlying structures), taste alteration and gingival enlargement.

Fainting situations can also occur to patients who have diabetes, and have a hypoglycemic episode. It is important for a diabetic patient to use a glucometer to take a reading of sugar level before treatment. If the reading is less than 70 mg/dl, then action should be taken.

Finally, asthma can be a factor in a dental office. It is important to probe the patient to determine information such as the severity of attacks, duration, when the last attack was, how they dealt with it (stayed at home, or hospital), what triggers it (odours in dental setting, and stres from appointment often can be a trigger). If the patient does have frequent attack, than an inhaler should be kept close and at the ready.

This is followed up by a physical examination, diagnosis, and finally an assessment of the benefits and risk of performing the treatment in mind.

General and Oral Histology

For histo, we discussed cementum, root and pulp structures of teeth. Cementum is found on the outer surface of the radicular part of a tooth, and is continuous with the periodontal ligament (PDL). It is anchored in the alveolar bone by Sharpey's fibers (type 1 collagen) which span the cementum and PDL. Pre-cementum is secreted by cementoblasts, and is slowly formed throughout life. The pre-cementum is mineralized by the cementoblasts, until its contents are about 50% hydroxyapatite crystals. Over time, cementoblasts may become mineralized in cementum and are called cementocytes. They help by diffusing nutrients from the vascularized PDL to the non-vascularized cementum.

There are a number of different kinds of cementum. Two of them include acellular extrinsic fiber cementum (AEFC) which contains no cementocytes, but has Sharpey's fibers from the PDL. Its function is to anchor the root to the PDL, and is often found in the cervical third of the root. Cellular intrinsic fiber cementum (CIFC) contains cementocytes and is important in repairing resporptive defects in the roots of teeth. Mixed stratified epithelium of both AEFC and CIFC are important in reshaping the tooth surface in order to compensate for drift and shifting of teeth in the alveolar sockets.

Some clinical problems that arise in the cementum include hypercementosis, where you get excessive deposition of cementum on the root surface. This can interfere with tooth extractions. Also, you may see concresence where the roots of two adjacent teeth are joined by cementum. This is often due to sufficient space during tooth development.

I'll finish up with roots and pulp later.