Oral Pathology: Inflammation and Infection

• Oral pathology studies and diagnoses diseases of the oral cavity and adjacent structures.
• It links dentistry and pathology, requiring knowledge in both.
• Oral pathologists use microscopic tissue examination, biopsies, and clinical data for oral disease diagnosis.

Inflammation and Infection

• Gingivitis causes gum inflammation, typically from bacterial plaque.
• Periodontitis, a severe gum disease, inflames and causes bone loss around teeth.
• Oral candidiasis (thrush), a fungal infection by Candida albicans, shows as white patches.
• Herpes simplex virus (HSV) causes oral herpes, marked by blisters or ulcers.
• Aphthous ulcers (canker sores) are common, painful ulcers with unknown causes.
• Cellulitis is a bacterial infection spreading in soft tissues, leading to swelling and redness.
• Osteomyelitis infects bone and can affect the jaws.

Benign Soft Tissue Lesions

• Fibromas are non-cancerous connective tissue tumors, often from trauma.
• Papillomas are non-cancerous epithelial tumors caused by human papillomavirus (HPV).
• Lipomas are benign, fatty tissue tumors appearing as soft, yellowish nodules.
• Pyogenic granulomas are inflammatory lesions forming rapidly growing masses, often on the gingiva.
• Peripheral giant cell granulomas are reactive lesions on the gingiva or alveolar ridge.
• Mucoceles are cyst-like lesions from mucus leaks from damaged salivary gland ducts.
• Ranulas are mucoceles in the mouth floor, usually involving the sublingual gland.

Malignant Soft Tissue Lesions

• Squamous cell carcinoma is the most frequent oral cancer, often related to tobacco and alcohol.
• Melanoma, rare in the mouth, is a dangerous skin cancer that can metastasize.
• Sarcomas are malignant connective tissue tumors, including fibrosarcoma and Kaposi's sarcoma.
• Lymphomas are lymphatic system cancers that can appear in the oral cavity.

Benign Osseous Lesions

• Torus palatinus and torus mandibularis are bony growths on the palate and mandible, respectively.
• Exostoses are similar bony growths found in the jaws.
• Odontomas are benign tumors of tooth-like tissues.
• Cementomas (periapical cemental dysplasia) affect the periapical bone around teeth.
• In fibrous dysplasia, normal bone is replaced by fibrous tissue.

Malignant Osseous Lesions

• Osteosarcoma is a primary bone cancer that can affect the jaws.
• Chondrosarcoma is a malignant cartilage tumor that can occur in the jaws.
• Metastatic tumors from other body sites can spread to the jaws.

Salivary Gland Disorders

• Sialadenitis is salivary gland inflammation, often from infection or blockage.
• Sialolithiasis is salivary gland stone (sialoliths) formation.
• Sjögren's syndrome is an autoimmune disorder causing dry mouth and eyes.
• Pleomorphic adenomas are the most common benign salivary gland tumors.
• Mucoepidermoid carcinoma is the most common malignant salivary gland tumor.

Odontogenic Cysts and Tumors

• Radicular cysts (periapical cysts) are inflammatory cysts linked to non-vital teeth.
• Dentigerous cysts surround the crown of an unerupted tooth.
• Odontogenic keratocysts (OKCs) are cysts with aggressive growth and recurrence potential.
• Ameloblastomas are benign but locally aggressive odontogenic tumors.
• Odontomas are common odontogenic tumors composed of enamel, dentin, and cementum.
• Ameloblastic fibromas are mixed odontogenic tumors with epithelial and mesenchymal components.

Vesiculobullous Diseases

• Pemphigus vulgaris is an autoimmune disease causing skin and mucous membrane blistering.
• Bullous pemphigoid is another autoimmune blistering disease, mainly in older people.
• Mucous membrane pemphigoid affects mucous membranes, including in the oral cavity.
• Erythema multiforme is an acute inflammatory condition causing skin and mucous membrane lesions.
• Lichen planus is a chronic inflammatory condition affecting skin and oral mucosa.
• Systemic lupus erythematosus (SLE) is an autoimmune disease with potential oral manifestations.

Pigmented Lesions

• Melanotic macules are flat, pigmented spots on the oral mucosa.
• Amalgam tattoos result from dental amalgam particles in the mucosa.
• Physiologic pigmentation refers to normal melanin pigmentation in some ethnic groups.

Developmental Disturbances

• Cleft lip and cleft palate are congenital malformations of the lip and palate.
• Fordyce granules are ectopic sebaceous glands, seen as small, yellowish spots.
• Ankyloglossia (tongue-tie) is a short lingual frenum condition.
• Dentinogenesis imperfecta is a genetic disorder affecting dentin, causing tooth discoloration.
• Amelogenesis imperfecta is a genetic disorder affecting enamel, causing abnormal enamel.

Systemic Diseases with Oral Manifestations

• Diabetes mellitus can raise the risk of periodontal disease and oral infections.
• HIV/AIDS can cause oral lesions like candidiasis, hairy leukoplakia, and Kaposi's sarcoma.
• Leukemia can lead to gingival enlargement, bleeding, and oral ulcerations.
• Anemia can cause oral pallor and glossitis.
• Crohn's disease and ulcerative colitis can show oral manifestations such as aphthous ulcers.

Diagnostic Techniques

• Biopsy involves removing tissue for microscopic examination to diagnose diseases.
• Incisional biopsy removes a small part of a lesion.
• Excisional biopsy removes the entire lesion.
• Cytology (oral brush test) is a non-invasive method to collect cells for examination.
• Radiographs (X-rays), CT scans, and MRI are imaging techniques to view bone and soft tissue.

Microscopic Features

• Hyperkeratosis is the thickening of the epithelium's keratin layer.
• Dysplasia is abnormal cell growth and maturation, potentially leading to malignancy.
• Carcinoma in situ is severe dysplasia that has not invaded the basement membrane.
• Invasion is the spread of malignant cells into surrounding tissues.

Study of diseases affecting the oral cavity. Includes gingivitis, periodontitis, oral candidiasis (thrush), herpes simplex virus (HSV). Also includes aphthous ulcers (canker sores), cellulitis and osteomyelitis. Focuses on diagnostic features and etiology.