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Putting the Pieces Together

The diagnostic approach used in oral pathology requires a methodical approach.

One of the most challenging areas in dental and dental hygiene practice is the diagnostic process. In oral pathology, there is nothing more important. The dentist is ultimately responsible for the definitive diagnosis of a lesion or condition in question. However, the dental hygienist plays a key role in the preliminary evaluation and data collection of oral pathologic conditions. Editor’s Note: Olga A.C. Ibsen, RDH,MS, will delve further into the diagnostics of oral pathology in future editions of this column.

There are eight categories in the diagnostic process: clinical, radiographic, historical, laboratory, microscopic, surgical, therapeutic, and differential findings.1 Diagnosis is like a puzzle and each piece contributes to the whole picture or final diagnosis. Applying these categories to a lesion or condition provides a very methodical approach to gathering information for the diagnosis. Diagnosis does not always mean using a scalpel and doing a biopsy.

When determining a diagnosis, reviewing all of the categories involved in the diagnostic process is important. Sometimes one category is sufficient for a final diagnosis and the strength of the diagnosis comes from that one aspect alone. However, there are times when more than one or several categories must be integrated in order to arrive at a final diagnosis.

Figure 1. Retrocuspid papillae: these are red, raised nodules found on the lingual gingiva of the mandibular cuspids.Images reprinted from Ibsen OAC, Phelan JA, Oral Pathology for the Dental Hygienist, 4th ed, Philadelphia


In clinical diagnosis, the strength of the diagnosis comes from the clinical picture alone. These conditions are often variants of normal. Even when the strength of the diagnosis comes from another category, the clinical component will always be a significant part of the final diagnosis. Following are some conditions diagnosed through clinical diagnosis alone.

  1. Fordyce Granules—ectopic sebaceous glands that usually appear in clusters of yellow papules on the buccal mucosa or lips in older individuals.
  2. Retrocuspid Papillae—developmental, raised red nodules found on the lingual gingiva of the mandibular cuspids (see Figure 1).
  3. Fissured Tongue—characterized by deep grooves on the dorsal surface of the tongue.
  4. Mandibular Toriunilateral or bilateral projections of dense compact bone found on the lingual aspect of the mandible in the premolar area.
  5. White Hairy Tongue—elongation of the filiform papillae on the dorsal surface of the tongue. The condition is usually caused by an increased accumulation of keratin, which results in the filiform papillae appearing white.
  6. Black Hairy Tongue—elongation and brown to black discoloration of the filiform papillae on the dorsal surface due to chromogenic bacteria. Smoking, alcohol, hydrogen peroxide rinses, and antacids can contribute to this condition.
  7. Exostosisprojections of dense compact bone on the labial and buccal surfaces of the maxillary or mandibular alveolar ridge.
  8. Leukoedemacharacterized by an opalescent hue of the buccal mucosa observed more commonly in black people. When the mucosa is stretched, the tissues appear normal.
    Figure 2. Internal resorption: a diffuse radiolucency is seen in the crown and root of this maxillary first molar.




In radiographic diagnosis, the strength of the diagnosis comes from the information revealed in the radiograph. The radiograph alone can be sufficient to establish a diagnosis but sometimes other diagnostic categories contribute to the final diagnosis.The following radiographs show one or both situations:

  1. Periapical Pathosisa radiolucency seen at the apex of the root of a tooth.
  2. Fistula—an abnormal tract from an internal area (often the apex of an involved tooth) to an external or outer surface. Fistulas can be clinical evidence of periapical pathosis.
  3. Internal Resorption—the diffuse radiolucency in the pulpal area of this maxillary first molar thought to be an inflammatory response of the pulp (see Figure 2).
  4. External Resorptionthe destruction of tooth structure from an outside source. This condition is not reversible.
  5. Calculus—radiopaque “spurs” that can be seen interproximally. Clinical evidence of supragingival calculus and gingival inflammation may also be present.
  6. Compound Odontomaradiopacities resembling tooth structure that are only observed radiographically.
  7. Calcified Pulp—when a part or all of the pulpal area in the tooth appears radiopaque and not radiolucent.
  8. Dentigerous Cyst—appears as a well-defined radiolucency around the crown of an unerupted tooth. This condition is often associated with a third molar or supernumerary tooth. A dentigerous cyst can often be suspected from the radiograph but final diagnosis is made after microscopic examination.
    Figure 3. Cementoma: the radiographic appearence of periapical cemento-osseous dysplasia as seen in this case.


The strength of the historical diagnosis may come from any aspect of the history of the patient or lesion. Some of this information may be a part of the patient’s medical history. However, patients must be questioned on what may be suspected from the clinical or radiographic findings.

Figure 4. Carcinoma: medium power microscopic view of a squamous cell carcinoma showing the tumor islands containing keratin pearls.
Figure 5. Pyogenic granuloma: appears on the labial papillae between the maxillary central and lateral incisors.
  1. Periapical Cemento-Osseous Dysplasiadiagnosis of this lesion cannot be made on the findings seen in the radiograph alone. In Figure 3, a radiolucency at the apex of several mandibular anterior teeth with some radiopacity is observed. This patient is a 37-year-old black woman who is asymptomatic. The radiolucent/radiopaque area was identified on an initial full mouth series. When pulp tested, the teeth were found to be vital. The history related to the radiograph makes the diagnosis. The patient’s age, sex, and race and the fact that the teeth are vital contribute the most significant information to the diagnosis. This lesion begins as a radiolucent area and in time, becomes more radiopaque, which, in this case, caused the mixed radiographic appearance. No treatment is necessary for this condition.
  2. Ulcerative Colitis—patients who have this condition may have oral ulcerations resembling recurrent aphthous ulcers. The patient’s medical history is significant because oral ulcerations can be associated with episodes of ulcerative colitis.
  3. Dentinogenesis Imperfectaa genetic, autosomal dominant condition affecting dentin. The clinical appearance of dentinogenesis imperfecta shows all teeth in both dentitions exhibiting a brown to blue opalescent hue. Therefore, a family history is most contributory to the diagnosis.
  4. Chemical Burn—a number of chemicals and drugs, when used improperly, can cause injury to oral tissues. Aspirin, phenol, and hydrogen peroxide are a few examples of products that patients may misuse, causing ulcerations and epithelial necrosis to the mucosa. If a patient places one or several aspirin directly in the mouth to alleviate dental pain, the necrosis of surrounding tissues is caused by the caustic composition of the aspirin. Clinically, a diffuse white area may be seen on the buccal mucosa. However, asking patients about their use/misuse of aspirin is most contributory to the diagnosis.


Laboratory diagnosis can involve blood chemistries, urinalysis, or cultures that can contribute to the definitive or final diagnosis.

  1. Paget Disease—characterized by “cotton wool” radiopacities in the bone. Hypercementosis of the roots of the teeth may also be observed radiographically. However, the serum alkaline phosphatase level is significantly elevated in this condition. Although there are distinct radiographic features, the laboratory test result is most contributory to the final diagnosis.


This diagnostic category is often the main component of a definitive or final diagnosis. Scalpel biopsy is used to obtain a tissue sample for complete microscopic evaluation. This procedure can be incisional or excisional. When in doubt, refer it out! The skill of the clinician performing the biopsy is of critical importance to the results.

The brush biopsy is a new technique used to obtain cells from the surface layer through the basal cell layer of the epithelium. In some states, dental hygienists may perform this procedure. The results of this test may help determine if a scalpel biopsy is needed to make a definitive diagnosis.

Carcinoma—malignant growth composed of epithelial cells. The microscopic specimen for this diagnosis (see Figure 4) was obtained through scalpel biopsy. This is a medium-power view of squamous cell carcinoma showing tumor islands containing keratin pearls, characteristic of a malignancy.


This category is not the same as microscopic diagnosis. The strength of this diagnostic category comes from surgical intervention itself.

  1. Stafne Bone Cyst—appears radiographically as a well-circumscribed, oval, radiolucency anterior to the angle of the ramus and inferior to the mandibular canal. During surgical intervention, the area will be filled with salivary gland tissue, thus establishing the diagnosis for Stafne bone cyst.
  2. Traumatic Bone Cyst—characterized radiographically as a radiolucent lesion that appears to scallop around the roots of teeth. When the surgeon opens into the lesion, a void within the bone is found, thus establishing the definitive diagnosis for traumatic bone cyst.


Therapeutic diagnosis is often applied to cases that have strong clinical and/or historical information associated with the lesion or condition. A complete medical history is an essential component to this category.

  1. Angular Cheilitismay appear as crusted, ulcerated areas in the commissures of the lips and is often bilateral. It is most often caused by Candida but nutritional deficiencies can also be the underlying cause. After a thorough medical history is secured to rule out a nutritional deficiency, a topical antifungal cream or ointment may be prescribed and the condition will resolve.
  2. Necrotizing Ulcerative Gingivitis (NUG)—characterized by significant clinical characteristics and constitutional signs. It is caused by anaerobic bacteria and will respond to hydrogen peroxide rinses. Additionally, antibiotics may be used to treat NUG.


Differential diagnosis is used when the clinician uses a test or procedure to rule out some of the conditions originally suspected.

  1. Pyogenic Granulomacharacterized by a proliferation of connective tissue containing numerous blood vessels and inflammatory cells and occurs as a response to injury. In Figure 5, a lesion between the maxillary central and lateral incisor appeared in an 11-year-old girl. A complete patient history and history of the lesion was provided by the mother. Based on that information, a differential diagnosis was submitted to the oral pathology laboratory with the scalpel biopsy. Possible diagnoses were: pyogenic granuloma due to mechanical irritation from the orthodontic bands; papilloma because of the papillary surface of the lesion; or verruca vulgaris because the patient had a wart, which is caused by a virus that could have spread. However, a wart is usually more keratinized, therefore, whiter in color than the lesion seen in Figure 5. After microscopic evaluation of the specimen was submitted, the final diagnosis was pyogenic granuloma.


Using these diagnostic categories, dental hygienists can follow a methodical approach to assist in a definitive or final diagnosis. In addition, the patient’s medical and dental history must be complete and reviewed with the patient. The patient should not just fill out a form. Often patients do not intentionally omit information; they may not think something is relevant to their dental health, they may forget, or they may be unclear as to what was requested in the question. Clinically, a lesion should be described using professional terminology and measurements. Patients should be asked multiple questions in terms of how long they have noticed the lesion (if at all), and if it has grown in size or changed shape or color. Radiographs must be of diagnostic quality since they contribute significantly to the diagnostic process. Diagnosis is a process and requires input from multiple aspects related to the condition.

Olga A.C. Ibsen, RDH, MS, is an adjunct professor at the University of New Haven, West Haven, Conn, and an adjunct professor in the Department of Oral Pathology at New York University College of Dentistry, New York.


1. Ibsen OAC, Phelan JA. Oral Pathology for the Dental Hygienist. 4th ed. Philadelphia: WB Saunders; 2004

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