Oral Pathology and Oral Medicine I: Special Exam, 26 July 2021

Mount Kenya University · Department of Dental Sciences · Diploma in Community Oral Health · DDS2107

Oral Pathology and Oral Medicine I past exam 2020-2021 from Mount Kenya University, includes model answers.

Instructions: Attempt ALL questions in Section A and any TWO (2) in Section B.

SECTION A (30 marks)

1. Explain classification of cleft lip. (10 marks)

Model answer
  • Embryologic basis: failure of fusion of the medial nasal and maxillary prominences during the 4‑8 week gestation period.
  • Types by location:
  • Complete (total) cleft lip: involves the entire lip extending to the nostril rim.
  • Incomplete (partial) cleft lip: only a portion of the lip is affected; may be unilateral or bilateral.
  • Cleft lip with alveolus: involves the lip and the alveolar ridge but not the palate.
  • Cleft lip and palate: extends posteriorly to involve the hard and/or soft palate.
  • Laterality:
  • Unilateral: more common on the left side.
  • Bilateral: involves both sides of the lip.
  • Severity grading (Veau classification):
  • Group I: cleft of the soft palate only.
  • Group II: cleft of the hard and soft palate.
  • Group III: unilateral cleft lip and palate.
  • Group IV: bilateral cleft lip and palate.
  • Associated anomalies: may be isolated or part of syndromic patterns (e.g., Van der Woude).

2. Differentiate between hyperdontia and hypodontia. (6 marks)

Model answer
  • Hyperdontia: presence of excess teeth (supernumerary) beyond the normal complement.
  • Hypodontia: congenital absence of one or more permanent teeth (excluding third molars).
  • Etiology: hyperdontia – often linked to genetic factors, syndromes (e.g., cleidocranial dysplasia); hypodontia – hereditary, environmental insults, or associated with ectodermal dysplasia.
  • Clinical presentation: hyperdontia – crowding, delayed eruption, possible cyst formation; hypodontia – spacing, delayed eruption of adjacent teeth, aesthetic concerns.
  • Management: hyperdontia – extraction if causing problems; hypodontia – orthodontic space closure or prosthetic replacement (bridge, implant).

3. Outline types of abrasion. (3 marks)

Model answer
  • Horizontal abrasion: loss of enamel on the incisal or occlusal edges due to aggressive tooth‑brush or abrasive diet.
  • Vertical (cervical) abrasion: notch at the gingival margin caused by improper brushing technique.
  • Combined (mixed) abrasion: features of both horizontal and vertical loss, often seen with mixed abrasive habits.

4. Describe amelogenesis imperfecta. (4 marks)

Model answer
  • Genetic heterogeneity: autosomal dominant, recessive or X‑linked patterns.
  • Enamel defect: thin, hypoplastic or hypomineralised enamel affecting all teeth.
  • Clinical types:
  • Hypoplastic type: enamel is thin, pitted, and chalky.
  • Hypomaturation type: enamel appears normal thickness but is soft and mottled.
  • Hypocalcified type: enamel is soft, easily worn away, and discoloured.
  • Inheritance of phenotype: often familial with variable expressivity.
  • Management: restorative care (composite, crowns), fluoride, oral hygiene reinforcement.

5. State clinical features of Ludwig's angina. (5 marks)

Model answer
  • Rapidly spreading submandibular and sublingual space infection.
  • Firm, woody swelling of the floor of mouth and neck.
  • Elevation of the tongue (tongue thrust) causing dysphagia and drooling.
  • Fever, malaise and possible trismus.
  • Tracheal compression leading to airway obstruction if untreated.
  • Crepitus or fluctuance may be present if abscess formation occurs.

6. What is herpetic gingivostomatitis? (2 marks)

Model answer
  • Acute viral infection of the oral mucosa caused by herpes simplex virus type 1, presenting with painful vesicles, ulceration and fever, most common in children.

SECTION B

7. Discuss pathological attrition. (20 marks)

Model answer
  • Definition: Pathological attrition is excessive loss of tooth structure due to abnormal mechanical forces, not related to normal wear.
  • Aetiology: Bruxism (sleep/awake), malocclusion, parafunctional habits, gastro‑oesophageal reflux, eating hard foods.
  • Clinical features: Flattened occlusal surfaces, cupped depressions, exposed dentine, sensitivity, shortened clinical crowns.
  • Radiographic signs: Reduced crown height, loss of enamel thickness, sometimes secondary dentine formation.
  • Differential diagnosis: Distinguish from physiological attrition (age‑related) and abrasion/erosion.
  • Complications: Increased caries risk, pulp exposure, hypersensitivity, compromised occlusion, periodontal trauma.
  • Management – preventive: Occlusal splints/night guards, stress management, correction of malocclusion, dietary advice.
  • Management – restorative: Composite or glass‑ionomer fillings for sensitivity, crowns on severely worn teeth, overlay dentures.
  • Prognosis: Depends on control of aetiological factors; early intervention can halt progression.
  • Patient education: Emphasise habit cessation, regular dental visits, use of protective appliances.
  • Follow‑up: Monitor wear rate, adjust appliances, reassess occlusion periodically.
  • Interdisciplinary care: Collaboration with orthodontists, physiotherapists, and psychologists when bruxism is stress‑related.
  • Public health aspect: Awareness programs on parafunctional habits and early detection in school screenings.
  • Research trends: Use of botulinum toxin for muscle hyperactivity, novel wear‑resistant restorative materials.
  • Legal/ethical considerations: Informed consent for appliance therapy and discussion of long‑term maintenance.
  • More answers: Use of occlusal equilibration, dietary modifications, fluoride varnish for sensitivity.

8. Write notes on hypercementosis. (20 marks)

Model answer
  • Definition: Hypercementosis is excessive deposition of cementum on the root surface, leading to thickened roots.
  • Aetiology: Chronic inflammation (periapical periodontitis), occlusal trauma, systemic conditions (Paget’s disease, hyperparathyroidism), idiopathic.
  • Types: Localised (single tooth) vs generalized (multiple teeth); focal vs diffuse.
  • Clinical appearance: Bulbous root enlargement, may feel hard on palpation; usually asymptomatic.
  • Radiographic features: Radiopaque enlargement of root outline, loss of periodontal ligament space at the thickened area, no root resorption.
  • Differential diagnosis: Cementoblastoma, periapical cemental dysplasia, root caries.
  • Complications: Difficulty in extraction, root fracture, interference with orthodontic movement, periodontal pocket formation.
  • Management – observation: No treatment needed if asymptomatic and not interfering with function.
  • Management – intervention: Surgical reduction of excess cementum before extraction, careful sectioning during extraction, orthodontic adjustment if needed.
  • Prevention: Control of chronic periapical inflammation, avoid excessive occlusal forces.
  • Prognosis: Good; condition is benign and non‑progressive once aetiological factor removed.
  • More answers: Association with systemic bone diseases, histological description (acellular cementum), impact on prosthetic design.

9. Explain the effects of cleft lip and palate. (20 marks)

Model answer
  • Feeding difficulties: Inability to create suction, nasal regurgitation, prolonged feeding time, risk of failure to thrive.
  • Speech development: Articulation problems, hypernasality, compensatory speech patterns, need for speech therapy.
  • Dental health: Increased risk of caries due to open mouth, malocclusion (crossbite, open bite), delayed eruption.
  • Ear, nose, throat complications: Recurrent otitis media, sinus infections, nasal obstruction from associated choanal atresia.
  • Psychosocial impact: Low self‑esteem, social stigma, bullying, reduced quality of life.
  • Nutritional issues: Need for specialized feeding devices, possible need for gastrostomy if severe.
  • Growth and development: Potential impact on facial growth, mid‑facial hypoplasia, altered maxillary arch form.
  • Surgical considerations: Timing of lip repair (3‑6 months) and palate repair (9‑18 months) to improve function.
  • Multidisciplinary care: Involvement of surgeons, orthodontists, speech therapists, nutritionists, psychologists.
  • Long‑term outcomes: Improved speech and feeding after repair, but some may require orthodontic or prosthetic intervention.
  • More answers: Hearing assessment and intervention, psychosocial support groups, educational accommodations.

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