Oral diseases are pathologic conditions that affect oral and maxillofacial tissues. Dental caries and periodontal diseases are the most common forms of oral diseases, but there are a wide variety of diseases that can occur in oral and maxillofacial tissues. These oral diseases range from metabolic, inflammatory, infectious, neoplastic, autoimmune, developmental, to idiopathic origin. Numerous oral conditions have overlapping clinical signs and symptoms, which make the diagnosis and management challenging for the dentist. However, a comprehensive understanding of clinical behavior will help in differentiating the various oral diseases and will provide a logical pathway to formulating a diagnosis.
High-quality clinical examination skills are a key factor to achieving a correct diagnosis.
Appropriate use of clinical descriptive terms is important in recognizing clinical characteristics of an oral condition.
A diagnostic algorithm or decision-making tree is a useful tool in a clinical situation where critical thinking or logical answering is required.
Correlating the clinical information with radiological and/or histopathologic interpretation is the correct approach for arriving a final diagnosis.
Not all oral conditions require treatment, but all oral conditions must have a diagnosis.
A clinical examination of the patient is essential to determine the nature of the pathologic condition and is significantly important in formulating a diagnosis. Dental surgeons possess an advantage in that they can see the part of the body that they are called upon to treat. The primary objective of routine clinical examination of the oral cavity is to distinguish between health and disease. Common symptoms of oral diseases include swelling, ulcer, color change, surface/textural changes, tenderness/pain, and functional changes. Epidemiologic details of oral disease can guide the dental practitioner into understanding the relevance of clinical conditions in their setting and of the public health impact of early recognition, assessment, and prevention or treatment care. Because of the low prevalence of oral diseases in the general dental practice, the general dentist has only a very low level of exposure to oral diseases, which makes diagnosis difficult. In addition, the shift in approach for disease diagnosis with an emphasis on imaging and laboratory technology has further reduced the skills and confidence in oral examination and clinical diagnosis. Despite the reliance on technology, recognition of abnormalities by the generalist is still required. A late recognition or poor examination skills can lead to incorrect diagnosis or a misdiagnosis, with delays in life-saving treatments. The purpose of this article is to provide (i) an approach in formulating clinical diagnosis and (ii) an outline of the clinical nature of oral diseases. Although the presentation of detailed clinical information of oral diseases is beyond the scope of this article, basic information and an introductory clinical outline of the most commonly encountered categories of oral diseases are presented. For the convenience of the reader, the topics discussed are the common categories of oral diseases, which are given in Box 1 .
Jaw and dental abnormalities
Benign and malignant oral conditions
Salivary gland disorders
Approach in Formulating Clinical Diagnosis
A step-by-step approach in gathering information on the pathologic condition presented and critical analysis of the findings are the most important elements in the logical formulation of diagnosis. Successful management of the pathologic condition is always preceded by the correct diagnosis. The steps in the diagnostic process are as follows: (1) patient communication, (2) structured extraoral and/or intraoral examination, (3) assessment and correlation of problem listing, (4) critical analysis of procured data, (5) formulation of differential and provisional diagnosis, (6) investigation, and (7) arriving at the definitive diagnosis.
The predominance of dental caries, pulpal and periapical pathologic conditions, and gingival or periodontal problems is higher when comparing oral lesions. Because of this, the dentist may often overlook oral lesions, although the lesions may not be so rare. Compounding the problem, dental patients may not complain to the dentist about their oral condition when there is no functional disturbance or pain or because of fear.
The clinical appearance of the oral lesion is very important in understanding the nature of the condition. The clinical description is the initial step in gathering examination details. The clinical presentation of various oral diseases may be similar, but the underlying cause of the diseases is different. The varied clinical presentations are white and red lesions, oral ulcerations, vesicle and blister, papillary, nodular, polypoid, macule, sessile, pedunculated, verrucous, erosion, or fissure. The descriptions of these terms are listed in Table 1 . The dental surgeon should be familiar with these terms and apply them to clinical characters while describing the lesions and categorizing and formulating differential diagnosis.
|White lesion||Lesion that appears as white patches|
|Red lesion||Lesion that appears as red patches|
|Oral ulceration||Lesion characterized by either loss of continuity of epithelium or total loss of surface epithelium|
|Blister||Superficial lesion characterized by clear fluid-filled swelling|
|Vesicle||Superficial blister with clear fluid-filled blister that is 5 or <5 mm in diameter|
|Bullae||Superficial blister with clear fluid-filled blister that is >5 mm in diameter|
|Pustule||Superficial blister filled with purulent exudate|
|Papillary||Growth of tumor or swelling showing numerous small fingerlike projections from the surface mucosa|
|Polypoid||Growth that resembles an intestinal polyp|
|Macule||Focal area of color change that is neither elevated nor depressed to adjacent mucosa|
|Papule||Raised solid lesion that is <5 mm in diameter|
|Nodular||Raised solid lesion that is >5 mm in diameter|
|Sessile||Base of the tumor or growth is the widest part of the lesion|
|Pedunculated||The base of the tumor or growth is narrow, and base appears similar to a stalk|
|Verrucous||Growth or tumor showing rough, irregular, and warty surface|
|Exophytic||Growth is characterized as protuberant or outward to the surface tissue|
|Endophytic||Growth is characterized as inward to the surface tissue|
|Erosion||Surface lesion is characterized by the partial or total loss of epithelium following rupture of blister (vesicle/bullae)|
|Fissure||Surface of the lesion that is either a narrow, slitlike ulceration or a groove|
|Petechia||Small, round, pinpoint-sized hemorrhage|
The diagnosis of oral lesions requires critical and cognitive skills. The dentist needs to apply logical skills in a step-by-step approach to create a possible and closest clinical diagnosis. The approach for an oral condition is a step-by-step process; the first step is to recognize the symptom of the oral condition: swelling, ulcer, color change, surface or textural changes, functional alteration, tenderness, or pain. The next step is to identify whether the lesion is inflammatory, infected developing, benign, reactive, or of malignant origin. The dental surgeon should be knowledgeable on diagnostic, inclusion, and exclusion criteria of the common oral conditions under various categories.
An assumption of the best diagnosis without the appropriate diagnostic approach is dangerous because serious conditions could be ignored. Recently, a case report gave an account of a misdiagnosis of Bell palsy made in a patient who had an extensive acute embolic stroke secondary to infective endocarditis. Although this is a case from medical practice, it highlights the importance of thorough examination and history, the minimization of diagnostic errors, and early recognition of care. Hence, it is important to organize the knowledge of oral diseases in a systematic manner, like a decision tree or a diagnostic algorithm, which places information in a step-by-step manner to arrive at a logical conclusion. Finkelstein and Hellstein reported a guide to clinical differential diagnosis of oral mucosal lesions, which is a diagnostic algorithm that is very useful in structuring and in drawing a clinical decision through the clinical presentation. Similar to this report, other diagnostic decision trees were simulated for exophytic oral conditions ( Fig. 1 ), oral erosions, and yellow oral lesions. Having good background information on commonly encountered oral diseases will strengthen the diagnostic process. For the purpose of the general dentist, significant common laboratory tests and medication management (adult dose) of dental infections are presented in Tables 2 and 3 .
|HbA1c||Below 6%, that is, <42 mmol/mol||HbA1c refers to glycated hemoglobin, and the test measures average plasma glucose concentration||Prediabetes, 6%–6.4%, that is, 42–47 mmol/mol
Diabetes, 6.5% or greater, that is, 48 mmol/mol or greater
|International normalized ratio||Without anticoagulant therapy: 1||Measures extrinsic clotting function||With anticoagulant, therapeutic range: 2–3|
|Prothrombin time||12.7–15.4 s||Measures extrinsic clotting function||Prothrombin time is prolonged in liver disease and impaires vitamin K production|
|Hemoglobin||10.5–18 g/dL||Measures oxygen-carrying capacity of blood||Elevated in polycythemia vera and decreased in hemorrhage and anemia|
|Hematocrit||32%–52%||Measures relative volume of cells||Elevated in polycythemia and dehydration, levels are decreased in hemorrhage, anemia|
|Red blood cell||4–6 million/mm 3||Measures oxygen-carrying capacity of blood||Elevated in polycythemia, heart disease, pulmonary disease, and reduced in hemorrhage and anemia|
|White blood cell||4000–11,000/mm 3||Measures host defense against inflammation||Elevated in inflammation, trauma, toxicity, and leukemia
Reduced in aplastic anemia, drug toxicity, and specific infections
|Platelets||150,000–400,000/mL||Measures clotting potential||Elevated in polycythemia, leukemia, severe hemorrhage, and reduced in thrombocytopenia purpura|