|Year : 2014 | Volume
| Issue : 2 | Page : 72-76
Oral Pathology in Clinical Dentistry: A systematic approach
Professor and Head, Department of Oral Pathology, Anil Neerukonda Institute of Dental Sciences, Visakhapatnam, Andhra Pradesh, India
|Date of Web Publication||28-Oct-2014|
R V Subramanyam
Department of Oral and Maxillofacial Pathology, Anil Neerukonda Institute of Dental Sciences, Sangivalasa, Visakhapatnam, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
| Abstract|| |
The dental clinician frequently comes across lesions that involve the hard and soft tissues of the oral cavity. Most of these conditions do not pose a diagnostic problem for the dental surgeon. However, the clinical dentist is sometimes accosted with a lesion, the diagnosis of which is not only challenging, but influencing the choice of treatment. This review article provides a systematic and logical approach for diagnosing common lesions encountered in the dental practice.
Keywords: Dental clinician, differential diagnosis, gingival growth, history, oral pathology, white lesion
|How to cite this article:|
Subramanyam R V. Oral Pathology in Clinical Dentistry: A systematic approach
. J Int Clin Dent Res Organ 2014;6:72-6
| Introduction|| |
Sir William Osler, a Canadian physician, once quoted "As is our pathology, so is our practice." Although it is virtually impossible to know all the oral lesions and conditions, a fundamental knowledge of oral pathology is essential to become a successful dental clinician (DC). Most dental physicians do not have a problem in diagnosing caries or periodontitis, the two most common lesions of the oral cavity. Diagnosis determines the treatment and sometimes if we fail to distinguish between reversible and irreversible pulpitis, or a benign and a malignant neoplasm, the choice of treatment becomes critical.
In the case of precursor lesions of oral carcinoma, the potentially malignant lesions graded as mild, moderate or severe dysplasias, and carcinoma in situ (CIS), the role of pathology in the diagnosis is indispensable. 
In spite of comprehensive oral pathology syllabus in III year Bachelor of Dental Surgery (BDS) course, the DC is often flummoxed trying to diagnose common and not-so-common lesions of the oral cavity. Though there is a lot of emphasis on histopathology during undergraduate days, preliminary diagnosis in general dental practice is based on comprehensive and methodical history taking and astute observation of clinical features. Only occasionally that a clinician requires confirmation of the diagnosis by means of biopsy or other methods. The clinician should never give a diagnosis based on intuition or guesswork. How does one arrive at a diagnosis? There are certain logical steps to reach the right diagnosis, and these steps are shown in [Figure 1].
| Step 1: Collection|| |
If you do not ask the right questions, you do not get the right answers. A question asked in the right way often points to its own answer. Asking questions is the A-B-C of diagnosis. Only the inquiring mind solves problems.
Edward Hodnett (American poet 1841-1920)
The first step is a collection of information by way of thorough history taking, which is often neglected. It is not only mandatory, but a professional responsibility to be aware of patient's medical history of diseases which may affect the patient's dental treatment. It is also equally important to take medication histories, not only to prevent prescription errors and consequent risks to patients but also to detect drug-related clinical and/or pathological changes. 
Though diagnosis might appear to be self-evident by inspection alone, co-existing diseases may undergo undetected and untreated.  Nevertheless, a good history taking also ensures a good doctor-patient relationship and many a time saves the need for expensive laboratory procedures.
| Step 2: Classification|| |
The classification of facts, the recognition of their sequence and relative significance is the function of science, and the habit of forming a judgment upon these facts unbiased by personal feeling is characteristic of what may be termed the scientific frame of mind.
Karl Pearson, The Grammar of Science
Most lesions of the oral cavity can be categorized into any of the following [Figure 2]: change of color (white, red, blue, pigmented or combination of these); loss of integrity of the mucous membrane (erosion, fissure, or ulcer, which could be primary or secondary); growth or swelling. Lesions may involve the tooth and/or bone, either alone or in combination with other soft tissue lesions (in the oral cavity or elsewhere), or the condition could be part of a syndrome.
When a dentist encounters an oral lesion, he/she should first try to fit the lesion according to any of these categories. Once the lesion has been pigeonholed, the next step is comparison.
| Step 3: Comparison|| |
Eliminate all other factors, and the one which remains must be the truth.
Sherlock Holmes Quote in Sir Arthur Conan Doyle's
"The Sign of Four," Chapter 1: "The Science of Deduction"
How do we go about mastering this art of differential diagnosis? [Figure 3] gives an approach to several aspects of differential diagnosis. The size of the lesion, whether they are single or multiple, or whether well-circumscribed or not, give an indication of the nature of the disease, when correlated with the patient's history. The clinical appearance can give a clue to the nature of the lesions - a macule can never be misdiagnosed as a papilloma! Similarly, some sites are common for certain types of lesions- for, e.g., a pyogenic granuloma is usually seen on the gingiva and unlikely to be seen on the floor of the mouth; by the same token, a ranula (a type of mucocele) is mostly likely to occur on the floor of the mouth and is not seen on the gingiva. A comprehensive evaluation of the possible etiology of the condition while taking history may sometimes give a clue to the diagnosis. This is especially true with hereditary disorders and developmental lesions. Palpation of the lesions can give an indication of the nature of the lesions- for example, whether it is cystic or neoplastic.
|Figure 3: Approach to various aspects of differential diagnosis of oral lesions|
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The color of the lesion, especially mucosal, is very useful for differential diagnosis. A homogenous white lesion is most likely to be leukoplakia, particularly in a person with tobacco consuming habit. A pigmented lesion in the gingiva adjacent to a tooth with faulty Class II amalgam restoration could be an amalgam tattoo. However, one should never look at the color of the lesion in isolation. For example: Is it a white patch, or a red papule, or a brown macule, or a pink nodule?
Intrabony lesions require radiographs for differential diagnosis- whether they are radiolucent (for, e.g., ameloblastoma, keratocyst), radiopaque (for, e.g., osteoma, odontoma) or mixed (for, e.g., Pindborg tumor, Gorlin cyst). Some lesions have a typical radiographic characteristic which give an indication of the diagnosis. For, e.g., cotton wool appearance of Paget disease, moth-eaten feature of osteomyelitis, sun-ray manifestation of osteosarcoma, and ground glass appearance of fibrous dysplasia. However, the dental physician should never give a diagnosis based solely on the radiographic appearance. For e.g., cotton wool appearance is not restricted to Paget disease and can be seen in condensing osteitis. Similarly, onion peel appearance of periosteal bone (due to neoperiosteitis) is seen in osteosarcoma, infantile cortical hypersostosis, Ewing sarcoma, Garré osteomyelitis and other conditions.
| Step 4: Clinical Impression|| |
For most diagnoses all that is needed is an ounce of knowledge, an ounce of intelligence, and a pound of thoroughness.
Based on all presenting features, that is, history, age, gender, clinical characteristics (appearance, site, location, signs and symptoms), radiological appearance (where applicable), and possible causes, the clinician should correlate all these with each other before venturing to give an opinion. If one methodically adheres to the steps of differential diagnosis, the final diagnosis is usually quite obvious. A white line on the buccal mucosa along the occlusal level is unmistakably linea alba and does not require any further investigations, or for that matter, treatment. Similarly, the clinical diagnosis of leukoedema, a bilateral white lesion of the cheeks that disappears on stretching the buccal mucosa, does not offer any difficulty in diagnosis. However, diagnosis is not always that simple. For example, if a dental surgeon encounters a white lesion or a gingival growth in the patient's mouth, how should he go about the determining the diagnosis? [Figure 4] gives a logical approach to a white lesion of the oral mucosa and [Figure 5] diagnostic methodology for a gingival growth or swelling.
|Figure 4: Diagnostic algorithm for a white lesion of the oral cavity (H/O - History of; OSMF - Oral submucous fibrosis; OSCC - Oral squamous cell carcinoma; PVL - Proliferative verrucous leukoplakia)|
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|Figure 5: Diagnostic algorithm for a growth or swelling of gingiva (H/P - histopathology)|
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| Step 5: Confirmation|| |
Diagnosis is not the end, but the beginning of practice.
Martin H. Fischer, American Physicist (1879-1962)
When one methodically approaches the patient with an oral lesion, the clinical diagnosis is, usually, not difficult and does not require any further investigations. However, there are certain lesions, even if we are sure of the diagnosis clinically, we require confirmation using other methods. Sometimes we need to take radiographs like intra oral periapical, orthopantomogram, or computed tomography scan etc., or do certain laboratory investigations (like HIV testing, serum Ca and alkaline phosphatase levels, hemoglobin estimation) or perform exfoliative cytology and/or biopsy.
Indications and contraindications of biopsy and cytology and their surgical procedures are beyond the scope of this paper. However, the DC can perform a simple procedure like punch biopsy on his own. [Table 1] lists lesions most suitable for biopsy in general dental practice.
|Table 1: Lesions suitable for biopsy by a dental clinician who is not an oral surgeon|
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Lesions <1 cm can be excised completely; on the other hand, larger lesions or suspected malignancies require incisional biopsy. Tissue taken from a carefully selected site representative of the lesion and should be placed in wide-mouthed container with 10% buffered formalin for fixation. If the specimen is bloody, it should be washed in saline before placing in the fixative; the volume of the fixative should be at least 10 times the volume of the specimen for optimal, rapid fixation.  Saline is not an alternative for formalin fixation. Studies have shown that if biopsy is placed in saline for 1 h, and then transferred to formalin fixative, distortion of tissues (cell vacuolization in basal layer of epithelium and reduced cohesiveness of collagen fibers in the connective tissue) take place, making the diagnosis problematic.  In case the dental surgeon believes that immunofluorescence would be necessary (for vesiculobullous lesions and/or autoimmune disorders), it is better to take two tissue samples: one in formalin for routine staining and the other in Michel's solution for direct immunofluorescence. 
The container should be tightly sealed and properly labeled with patient's name, age, gender and site. If biopsy has been taken from multiple sites, separate bottles must be used indicating the site (especially right or left sides). The specimen should be sent to an oral pathologist, along with appropriate documentation, at the earliest. Nevertheless, the DC is advised to refer the patient to an oral surgeon if they are unsure of the type of the biopsy procedure required or for more complicated and/or extensive lesions.
| Step 6: Conclusion|| |
Learn to see, learn to hear, learn to feel, learn to smell and know that by practice alone can you become experts.
Sir William Osler, Canadian Physician (1849-1919)
The practice of dentistry is essentially an art, standing on the easel of science. The initial diagnosis is based on the history and clinical features. The dentist should start looking at the various causative factors and the likely diagnostic possibilities- which again may require collection of more information and in-depth clinical examination of the patient. Sometimes when the clinical diagnosis does not seem to correlate with the etiological factors or the results of laboratory or radiological investigations, the pathology (biopsy report) provides the final diagnosis. Clinician should suspect a diagnosis… never expect it!
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| Authors|| |
About the author
Dr Subramanyam completed his BDS from Annamalai University (1986) and pursued his MDS (Oral Pathology & Microbiology), from Nair Hospital Dental College, University of Bombay (1990). He has a vast of teaching experience of 25 years. He is a recognized PhD Guide for Dr NTRUniversity of Health Sciences. He has more than 55 Invited orations - national and international and 15 [International and National] publications to his credit. He is Member, Editorial Board of Journal of Translational Medicine. He has been past-editor of Journal of IAOMP. He is a resource Person for "Training the Teachers" by Dr NTRUniversity of Health Sciences. He has an online portal Webmaster of Oral Pathology Online: http://www.oralpath.org.in/.
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]