Oral Pathology and Oral Medicine I: Main Exam, 14 July 2026
Mount Kenya University · Department of Dental Sciences · Diploma in Community Oral Health · DDS2107
Oral Pathology and Oral Medicine I past paper from Mount Kenya University 2025-2026 with model answers.
Instructions: ATTEMPT ALL QUESTIONS IN SECTION A AND ANY OTHER TWO (2) IN SECTION B
SECTION A (30 marks)
1. The condition characterised by unilateral enlargement of one side of the face due to overgrowth of hard and soft tissues is called: A. Micrognathia B. Macrognathia C. Hemifacial hypertrophy D. Cleidocranial dysostosis (1 marks)
- C. Hemifacial hypertrophy – unilateral overgrowth of hard and soft facial tissues.
2. A small mandible is referred to as: A. Micrognathia B. Macrognathia C. Prognathism D. Retrognathia (1 marks)
- A. Micrognathia – term for a small mandible.
3. The congenital anomaly characterised by the absence of the clavicles and delayed closure of the fontanelles is: A. Cleft lip B. Micrognathia C. Cleidocranial dysostosis D. Hemifacial hypertrophy (1 marks)
- C. Cleidocranial dysostosis – absence of clavicles and delayed fontanelle closure.
4. The visible yellow spots on the buccal mucosa near the commissures that represent ectopic sebaceous glands are called: A. Fordyce's spots B. Leukoplakia C. Erythroplakia D. Lichen planus (1 marks)
- A. Fordyce's spots – ectopic sebaceous glands appearing as yellow buccal mucosal spots.
5. The fissured tongue condition characterised by multiple grooves on the dorsal surface is called: A. Median rhomboid glossitis B. Fissural tongue C. Hairy tongue D. Cleft tongue (1 marks)
- B. Fissural tongue – multiple grooves on the dorsal tongue surface.
6. A hereditary condition affecting enamel formation resulting in abnormal enamel that is soft, rough, or pitted is called: A. Dentinogenesis imperfecta B. Amelogenesis imperfecta C. Enamel hypoplasia D. Dental fluorosis (1 marks)
- B. Amelogenesis imperfecta – hereditary enamel defect causing soft, rough or pitted enamel.
7. The most common supernumerary tooth found between the maxillary central incisors is the: A. Paramolar B. Distomolar C. Mesiodens D. Supplemental lateral incisor (1 marks)
- C – Mesiodens is the most common supernumerary tooth located between the maxillary central incisors.
8. A tooth that appears excessively large in size is described as: A. Microdontia B. Macrodontia C. Fusion D. Gemination (1 marks)
- B – Macrodontia describes a tooth that is excessively large in size.
9. The developmental anomaly where a tooth has an abnormally long pulp chamber extending into the root is called: A. Talon cusp B. Dilaceration C. Taurodontism D. Odontome (1 marks)
- C – Taurodontism is the anomaly with an elongated pulp chamber that extends into the root.
10. An extra cusp projecting from the lingual surface of an anterior tooth is called: A. Talon cusp B. Cusp of Carabelli C. Dens invaginatus D. Dens evaginatus (1 marks)
- A – A talon cusp is an extra cusp projecting from the lingual surface of an anterior tooth.
11. The pathological wearing away of tooth structure due to tooth-to-tooth contact is called: A. Abrasion B. Attrition C. Erosion D. Abfraction (1 marks)
- B – Attrition is the pathological wear of tooth structure due to tooth‑to‑tooth contact.
12. The loss of tooth structure caused by chemical dissolution (acid) not involving bacteria is called: A. Attrition B. Abrasion C. Erosion D. Abfraction (1 marks)
- C – Erosion is the loss of tooth structure by chemical dissolution (acid) without bacterial involvement.
13. Excessive deposition of cementum on the root surface is called: A. Hypercementosis B. Cemental resorption C. Cementoblastoma D. Cemental hypoplasia (1 marks)
- A. Hypercementosis – excessive cementum deposition on root surface
14. The most common fungal infection of the oral cavity is: A. Herpes simplex B. Actinomycosis C. Candidosis D. Tuberculosis (1 marks)
- C. Candidosis – the most common oral fungal infection
15. The causative organism of syphilis is: A. Mycobacterium tuberculosis B. Treponema pallidum C. Streptococcus pyogenes D. Candida albicans (1 marks)
- B. Treponema pallidum – causative agent of syphilis
16. A rapidly spreading, life-threatening infection involving the submandibular, sublingual, and submental spaces bilaterally is called: A. Acute necrotising gingivitis B. Ludwig's angina C. Tuberculosis D. Actinomycosis (1 marks)
- B. Ludwig's angina – rapidly spreading, life‑threatening infection of submandibular, sublingual and submental spaces
17. The virus that causes chickenpox and shingles is: A. Herpes simplex virus type 1 B. Herpes simplex virus type 2 C. Varicella-zoster virus D. Coxsackie virus (1 marks)
- C. Varicella‑zoster virus – causes chickenpox and shingles
18. The absence of a salivary gland is called: A. Atresia B. Agenesis C. Aberrant tissue D. Sialolithiasis (1 marks)
- B. Agenesis – congenital absence of a salivary gland
19. The presence of a stone (calculus) within a salivary gland duct is called: A. Sialadenitis B. Sialolithiasis C. Ranula D. Mucocele (1 marks)
- B. Sialolithiasis – a calcified stone forming in a salivary duct
20. A bluish, translucent swelling in the floor of the mouth caused by obstruction of the sublingual gland duct is called: A. Mucocele B. Ranula C. Sialocele D. Haemangioma (1 marks)
- B. Ranula – bluish translucent swelling from obstructed sublingual gland duct
21. The autoimmune disorder characterised by dry mouth (xerostomia) and dry eyes (keratoconjunctivitis sicca) is: A. Sicca syndrome B. Lupus erythematosus C. Scleroderma D. Pemphigus vulgaris (1 marks)
- A. Sicca syndrome – autoimmune xerostomia with keratoconjunctivitis sicca
22. A recurrent, painful, round ulcer with a yellow-grey centre and red halo, usually lasting 7-14 days, is called: A. Herpetiform ulcer B. Major aphthous ulcer C. Minor aphthous ulcer D. Traumatic ulcer (1 marks)
- C. Minor aphthous ulcer – recurrent small painful ulcer with yellow‑grey centre and red halo lasting 1–2 weeks
23. The definition of an ulcer is: A. A raised solid lesion B. A fluid-filled blister C. A break in the epithelial continuity D. A flat pigmented area (1 marks)
- C. A break in the epithelial continuity – definition of an ulcer
24. The condition where a tooth is bent or angulated due to trauma during root development is called: A. Gemination B. Fusion C. Dilaceration D. Concrescence (1 marks)
- C. Dilaceration – tooth bent/angulated due to trauma during root formation
25. The union of two adjacent tooth germs resulting in a single large tooth is called: A. Gemination B. Fusion C. Concrescence D. Dens invaginatus (1 marks)
- B. Fusion – two adjacent tooth germs unite to form one enlarged tooth
26. The most common site for a mucocele is: A. Upper lip B. Lower lip C. Palate D. Floor of mouth (1 marks)
- D. Floor of mouth – mucoceles most frequently arise on the floor of the mouth
27. The congenital condition characterised by a short lingual frenulum restricting tongue movement is called: A. Cleft tongue B. Ankyloglossia C. Microglossia D. Macroglossia (1 marks)
- B. Ankyloglossia – a short, tight lingual frenulum limiting tongue movement
28. The reddish, smooth, depapillated area on the midline of the dorsal tongue is called: A. Hairy tongue B. Geographic tongue C. Median rhomboid glossitis D. Fissured tongue (1 marks)
- C. Median rhomboid glossitis – a smooth, red, depapillated patch on the dorsal midline
29. Tetracycline staining of teeth occurs when the drug is taken during: A. Adulthood B. Tooth development C. After tooth eruption D. Old age (1 marks)
- B. Tooth development – tetracycline binds to calcium during odontogenesis causing intrinsic staining
30. Acute necrotising gingivitis (ANG) is also known as: A. Trench mouth B. Thrush C. Herpes simplex D. Angular cheilitis (1 marks)
- A. Trench mouth – acute necrotising gingivitis is historically termed trench mouth
SECTION B
31. Discuss the developmental abnormalities affecting the dental hard tissues. (20 marks)
- Enamel defects
- Amelogenesis imperfecta: genetic defect in enamel formation, thin or hypoplastic enamel.
- Dental fluorosis: excess fluoride during enamel maturation, mottled opaque patches.
- Enamel hypomineralisation (MIH): post‑eruptive breakdown of molars/incisors, porous enamel.
- Dentine defects
- Dentinogenesis imperfecta: autosomal dominant, opalescent teeth, bulbous crowns, pulp obliteration.
- Dentin dysplasia: root malformation, short or absent roots, pulp chambers may be obliterated.
- Regional odontodysplasia (ghost teeth): hypoplastic enamel and dentine, thin crowns, large pulp chambers.
- Combined enamel‑dentine anomalies
- Hypophosphatasia: defective mineralisation of both enamel and dentine, premature loss of primary teeth.
- Osteogenesis imperfecta: dentin fragility, translucent teeth, frequent fractures.
- Root anomalies
- Taurodontism: enlarged pulp chamber, apical displacement of furcation, associated with syndromes.
- Short root anomaly: reduced root length, often familial, predisposes to mobility.
- Shape and number anomalies
- Dens invaginatus: enamel organ folds into pulp chamber, creating a deep pit.
- Dens evaginatus: tubercle of enamel/dentine on cusp tip, may fracture.
- Hyperdontia (supernumerary teeth): extra teeth, may impede eruption.
- Hypodontia/oligodontia: congenitally missing teeth, common in cleft palate.
- Syndromic associations
- Ellis‑van Creveld, ectodermal dysplasia, Down syndrome: characteristic dental hard‑tissue changes.
- Environmental influences
- Trauma to primary teeth affecting permanent tooth development (enamel hypoplasia, dilaceration).
- Management considerations
- Early diagnosis, protective restorations, orthodontic planning, genetic counselling where appropriate.
32. Discuss the common infections of the oral cavity. (20 marks)
- Bacterial infections
- Dental caries: Streptococcus mutans and lactobacilli demineralise enamel, leading to cavitation.
- Acute necrotising ulcerative gingivitis (ANUG): fusiform bacilli and spirochetes cause painful ulcerated papillae.
- Periodontal abscess: polymicrobial infection of periodontal pocket.
- Viral infections
- Herpes simplex virus (HSV‑1) – primary herpetic gingivostomatitis: vesicles → ulcerations, fever.
- Human papillomavirus (HPV): oral warts, potential malignant transformation.
- Coxsackievirus (hand‑foot‑mouth disease): vesicular lesions on oral mucosa.
- Fungal infections
- Oral candidiasis (thrush): Candida albicans overgrowth, pseudomembranous, erythematous or angular forms.
- Histoplasmosis/Paracoccidioidomycosis: rare granulomatous lesions in immunocompromised.
- Protozoal infections
- Entamoeba histolytica: amebic ulceration of the oral cavity, usually secondary.
- Mixed infections
- Acute necrotising ulcerative periodontitis: synergistic bacterial‑viral‑fungal involvement.
- Systemic conditions predisposing to infection
- Diabetes mellitus: impaired neutrophil function, higher candida prevalence.
- HIV/AIDS: recurrent oral candidiasis, HSV, Kaposi sarcoma.
- Prevention & control
- Oral hygiene, fluoride, antimicrobial mouth rinses, vaccination (HPV), glycaemic control in diabetics.
- Clinical features for differentiation
- Location, lesion type (vesicle, ulcer, plaque), pain level, systemic signs.
33. Discuss salivary gland diseases and oral ulcerations. (20 marks)
- Salivary gland obstructive disorders
- Sialolithiasis: calcified stones in Wharton’s (submandibular) or parotid ducts, cause painful swelling.
- Ductal strictures or mucous plugs: result from chronic inflammation, lead to recurrent sialadenitis.
- Inflammatory diseases
- Acute sialadenitis: bacterial infection (Staph aureus) of a gland, rapid onset pain, fever.
- Chronic sialadenitis: recurrent inflammation, fibrosis, reduced flow.
- Autoimmune disorders
- Sjögren’s syndrome: lymphocytic infiltration of exocrine glands, xerostomia, dry eyes, increased caries risk.
- IgG4‑related disease: painless swelling, dense IgG4‑positive plasma cells.
- Neoplastic conditions
- Benign: pleomorphic adenoma (most common), Warthin tumour (parotid), cystadenoma.
- Malignant: mucoepidermoid carcinoma, adenoid cystic carcinoma, carcinoma ex pleomorphic adenoma.
- Systemic causes of xerostomia
- Medications (anticholinergics, antihistamines), radiotherapy to head‑neck, dehydration.
- Oral ulcerations – classification
- Traumatic: mechanical (sharp tooth, denture), chemical (irritants), thermal.
- Infective: viral (HSV, Coxsackie), fungal (candidiasis), bacterial (ANUG).
- Immunologic: aphthous ulcers (minor, major, herpetiform), lichen planus (erosive type).
- Neoplastic: early squamous cell carcinoma presenting as non‑healing ulcer.
- Systemic disease‑related: Behçet’s disease, inflammatory bowel disease, HIV‑related ulcers.
- Clinical features to note
- Duration, pain, border definition, base (pseudomembrane vs granulation), associated systemic signs.
- Management principles
- Identify and remove cause (stone extraction, adjust denture), treat infection (antibiotics/antivirals), saliva substitutes for xerostomia, refer for biopsy of suspicious ulcers, multidisciplinary care for autoimmune conditions.
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