Home/Quiz/100+ LDS Part 1 Practice Questions Free Quiz 100+ LDS Part 1 Practice Questions Free Quiz Welcome to your 100+ LDS Part 1 Practice Questions Free Quiz 1. A 48-year-old woman attends the dental clinic complaining of a persistent dry mouth for the past 12 months. She reports difficulty swallowing dry foods, frequently needs to sip water while speaking, and has experienced an increase in dental caries. She also describes a persistent gritty sensation in both eyes. Clinical examination reveals dry oral mucosa and reduced salivary flow. An autoimmune process causing lymphocytic destruction of the exocrine glands is suspected. Sarcoidosis Systemic lupus erythematosus Sjögren syndrome Scleroderma Behçet disease None 2. A 26-year-old patient with a history of severe persistent asthma develops sudden breathlessness during dental treatment. The patient is distressed, has difficulty completing sentences, and has widespread expiratory wheeze. Treatment is stopped and the patient uses their own reliever inhaler, but there is inadequate improvement in symptoms. Which drug should be administered next via a large-volume spacer or nebuliser? Beclometasone Salbutamol Ipratropium bromide Hydrocortisone Adrenaline None 3. A 35-year-old patient requires extraction of a grossly carious mandibular first molar. Before extraction, the dentist administers a local anaesthetic injection near the mandibular foramen. A few minutes later, the patient reports numbness of the lower lip, and the mandibular molar teeth on the injected side are anaesthetised. Which nerve provides sensory innervation to these teeth and is the principal nerve targeted by this injection? Lingual nerve Long buccal nerve Auriculotemporal nerve Inferior alveolar nerve Mental nerve None 4. A 62-year-old patient attends for a dental extraction. His medical history includes rheumatic fever in childhood and subsequent prosthetic heart valve replacement. He is concerned about developing infective endocarditis and asks whether he should routinely receive antibiotics before dental treatment. According to current NICE guidance in the UK, which of the following is the most appropriate approach? Antibiotic prophylaxis is mandatory before all dental procedures Antibiotic prophylaxis is mandatory only before dental extractions Antibiotic prophylaxis is routinely recommended because of the prosthetic valve Antibiotic prophylaxis is not routinely recommended before dental procedures Antibiotic prophylaxis is required only if the patient previously had rheumatic fever None 5. A 57-year-old man is referred to an oral medicine clinic after his dentist identifies a persistent white patch on the lateral border of the tongue. The lesion cannot be wiped away and has remained present for several months. There is no obvious local traumatic cause. The patient has a 25-year history of cigarette smoking. Which of the following is a recognised oral potentially malignant disorder (OPMD)? Leukoedema Oral leukoplakia Fordyce granules Geographic tongue Linea alba None 6. A 24-year-old woman attends her general dental practitioner complaining of recurrent painful oral ulcers occurring several times a year. Examination reveals three discrete, shallow, round ulcers measuring approximately 4–6 mm, with a yellow-grey fibrinous base and an erythematous margin, affecting the labial and buccal mucosa. She reports that previous episodes usually resolve spontaneously within 10–14 days without scarring. There are no skin, ocular or genital lesions. What is the most likely diagnosis? Major recurrent aphthous stomatitis Minor recurrent aphthous stomatitis Recurrent intraoral herpes simplex infection Erythema multiforme Behçet disease None 7. A 42-year-old patient is prescribed metronidazole for an acute odontogenic infection. During counselling, the patient asks whether he can drink alcohol while taking the medication. Which of the following is the most appropriate reason for advising the patient to avoid alcohol during metronidazole therapy? Alcohol markedly reduces gastrointestinal absorption of metronidazole Alcohol causes rapid renal elimination of metronidazole The combination may produce a disulfiram-like reaction Alcohol converts metronidazole into a nephrotoxic metabolite The combination causes irreversible inhibition of hepatic microsomal enzymes None 8. A 29-year-old patient attends for a routine dental examination. Clinical examination reveals a soft, adherent deposit along the gingival margins, particularly in areas where oral hygiene is inadequate. The dentist explains that this deposit contains organised communities of microorganisms embedded within a self-produced extracellular matrix and plays an important role in the development of dental caries and periodontal disease. Which of the following best describes dental plaque? A calcified deposit composed predominantly of calcium phosphate salts An unstructured accumulation of food debris and desquamated epithelial cells A structured microbial biofilm adherent to teeth and other oral surfaces A proteinaceous film formed exclusively from salivary glycoproteins A mineralised bacterial deposit that cannot be removed by toothbrushing None 9. A 21-year-old dental student is reviewing the composition of dental hard tissues. During a discussion of enamel demineralisation, the tutor explains that mature enamel is the most highly mineralised tissue in the human body, with approximately 96% of its weight consisting of inorganic material. Which of the following is the predominant mineral component of mature dental enamel? Calcium carbonate Brushite Hydroxyapatite Fluorapatite Octacalcium phosphate None 10. An anxious 10-year-old patient requires extraction of a retained primary molar. Despite appropriate behavioural management, the child remains apprehensive but is cooperative and able to communicate. The dentist decides to use conscious inhalation sedation, allowing rapid adjustment of the sedation level while maintaining verbal contact with the patient. Which agent is most commonly used for inhalation sedation in dentistry? Sevoflurane Nitrous oxide Midazolam Propofol Ketamine None 11. A 68-year-old man develops central crushing chest pain during a dental extraction. He has a history of stable angina and carries glyceryl trinitrate (GTN) spray. After stopping treatment, reassuring the patient, and administering GTN, the pain persists for more than 15 minutes. He becomes pale, cold and sweaty and complains that the pain is radiating to his left arm and jaw. Which clinical feature is most suggestive of an acute myocardial infarction (AMI) rather than stable angina? Chest pain relieved promptly by glyceryl trinitrate (GTN) Chest discomfort precipitated by exertion and relieved by rest Persistent chest pain associated with pallor and sweating despite GTN Brief episodes of chest tightness lasting less than 5 minutes Chest pain occurring only during emotional stress and resolving spontaneously None 12. A 58-year-old woman with systemic lupus erythematosus has been taking prednisolone 10 mg daily for the past 18 months. She is scheduled for multiple dental extractions under local anaesthesia. During the preoperative assessment, the dentist considers the implications of her long-term corticosteroid therapy. Why may this patient be at increased risk during stressful dental treatment? Increased histamine release causing anaphylaxis Suppression of the hypothalamic–pituitary–adrenal (HPA) axis leading to adrenal insufficiency Increased platelet aggregation causing myocardial infarction Excess endogenous cortisol production causing hypertension Accelerated hepatic metabolism of local anaesthetic agents None 13. A 54-year-old man attends for assessment of a fractured mandibular molar. He requests immediate treatment because he is in discomfort. Before deciding whether the tooth should be restored or extracted, the dentist performs a comprehensive assessment, including a review of the patient's medical history, clinical examination, and radiographic findings. Which of the following is the most appropriate first step when planning any restorative or surgical dental treatment? Obtain informed consent for the planned procedure Prescribe prophylactic antibiotics Perform a comprehensive history and clinical examination to establish a diagnosis Schedule the patient for definitive treatment immediately Select the restorative material before discussing treatment options None 14. A 35-year-old patient with Sjögren syndrome complains of persistent dry mouth and has developed several new cervical and root surface carious lesions over the past year. The dentist explains that the patient's reduced salivary flow has significantly impaired the natural protective mechanisms of the oral cavity. A neutral salivary pH and adequate salivary flow protect against dental caries mainly by: Increasing enamel permeability to fluoride Eliminating all cariogenic bacteria from dental plaque Buffering plaque acids and promoting remineralisation of enamel Increasing the thickness of the acquired pellicle to prevent bacterial adhesion Stimulating the production of intrinsic factor None 15. A 42-year-old patient presents with gingival recession affecting the maxillary canine. On examination, the exposed root surface begins at the anatomical neck of the tooth, where the highly mineralised crown tissue transitions to the root covering. The dentist explains that this landmark is important when assessing cervical lesions and periodontal attachment loss. Which structure marks the junction at which enamel meets cementum at the neck of the tooth? Dentinoenamel junction (DEJ) Cementodentinal junction (CDJ) Alveolar crest Cementoenamel junction (CEJ) Gingival sulcus None 16. A 6-year-old child attends for a routine dental examination. The parent is unaware that the first permanent molars erupt without replacing any primary teeth and mistakes the newly erupted tooth for a deciduous molar. The dentist explains the normal eruption sequence to emphasise the importance of preventing early caries in this tooth. At what approximate age does the permanent mandibular first molar typically erupt? 4–5 years 6–7 years 8–9 years 10–11 years 12–13 years None 17. A 56-year-old man taking nifedipine for hypertension and a 30-year-old woman taking phenytoin for epilepsy both attend for routine dental examinations. On intraoral examination, the dentist notes a painless enlargement of the interdental papillae and marginal gingivae, making plaque control difficult. Which adverse effect is most strongly associated with the long-term use of both nifedipine and phenytoin? Oral candidiasis Gingival overgrowth (gingival hyperplasia) Xerostomia Osteonecrosis of the jaw Tooth discoloration None 18. A 38-year-old patient requests a routine "check-up X-ray" before undergoing a simple restoration, despite having no symptoms, no clinical signs of disease, and recent radiographs available. The dentist explains that dental radiographs should only be prescribed when the expected diagnostic benefit outweighs the potential radiation risk. According to the principle of justification in dental radiography, a radiograph should only be taken when: The patient specifically requests one It is routinely taken at every recall visit A lead apron is available The exposure can be made using a digital sensor The expected diagnostic or therapeutic benefit outweighs the radiation risk None 19. A 52-year-old man attends for a routine dental examination. He reports occasional bleeding while brushing but no significant pain. Clinical examination reveals generalised plaque and calculus deposits, periodontal pockets of 5–6 mm, clinical attachment loss, and horizontal alveolar bone loss on radiographs. The disease has progressed slowly over several years. Which of the following best characterises chronic periodontitis? Rapid periodontal attachment loss occurring in otherwise healthy adolescents Plaque-associated inflammation resulting in progressive loss of periodontal attachment and alveolar bone Acute necrotising infection characterised by punched-out interdental papillae and severe pain Gingival inflammation without loss of periodontal attachment or alveolar bone Periodontal destruction caused primarily by viral infection in the absence of dental plaque None 20. A 45-year-old patient attends for a routine dental examination and asks for a full-mouth series of radiographs "just to make sure everything is fine." Clinical examination reveals no symptoms, no signs of disease, and previous radiographs taken recently that remain diagnostically adequate. The dentist explains the principles of radiation protection before deciding whether further imaging is required. According to the principle of justification in dental radiography, a radiograph should only be taken when: The patient requests an X-ray for reassurance It is part of every routine dental examination The expected diagnostic or therapeutic benefit outweighs the radiation risk Digital radiography is available, reducing radiation dose The patient signs a consent form for the exposure None 21. A 16-year-old patient frequently consumes sugary carbonated drinks between meals. During an oral health education session, the dentist explains that plaque bacteria ferment dietary carbohydrates, producing organic acids that lower the plaque pH. Once the pH falls below the critical level, enamel begins to lose mineral. Below which approximate enamel pH does demineralisation begin (the critical pH)? 7.0 6.5 5.5 4.5 3.5 None 22. A newly qualified dentist is deciding whether to use a recently introduced restorative material. Before making a decision, she critically appraises the available clinical research, considers her own clinical experience, and discusses the patient's preferences and expectations before recommending a treatment. Which of the following best describes evidence-based dentistry? Using only the findings of the latest published research to make clinical decisions Following expert opinion regardless of the available scientific evidence Integrating the best available research evidence with clinical expertise and the patient's needs and preferences Providing the treatment preferred by the patient irrespective of scientific evidence Using only personal clinical experience when planning treatment None 23. A 30-year-old patient with a low caries risk attends for a routine dental examination and asks which fluoride toothpaste they should use to maintain good oral health. The dentist follows the current UK Delivering Better Oral Health (DBOH) guidance when making a recommendation. When prescribing fluoride toothpaste for caries prevention, current UK guidance (Delivering Better Oral Health) recommends that adults at standard risk use toothpaste containing at least: 500 ppm fluoride 1,000 ppm fluoride 1,350 ppm fluoride 2,800 ppm fluoride 5,000 ppm fluoride None 24. A 64-year-old man completed radiotherapy for squamous cell carcinoma of the oropharynx two years ago. He now presents with a grossly carious mandibular molar within the previously irradiated field. The dentist explains that extraction carries a significant long-term risk because of the reduced vascularity and healing capacity of irradiated bone. A patient who has had radiotherapy to the head and neck is at increased risk of which serious complication following a dental extraction in the irradiated field? Alveolar osteitis (dry socket) Osteomyelitis Osteoradionecrosis of the jaw Medication-related osteonecrosis of the jaw (MRONJ) Pathological root resorption None 25. A 48-year-old woman with asthma has been using an inhaled corticosteroid for several years. She attends complaining of a sore mouth and altered taste. Intraoral examination reveals creamy white plaques on the palate and buccal mucosa that wipe off easily, leaving an erythematous, slightly bleeding surface beneath. What is the most likely diagnosis? Pseudomembranous candidiasis (oral thrush) Oral leukoplakia Oral lichen planus Frictional keratosis Chronic hyperplastic candidiasis None 26. A 68-year-old complete denture wearer presents with diffuse erythema of the palatal mucosa beneath a maxillary complete denture. The denture is worn continuously, including overnight. Which fungal organism is most commonly associated with denture stomatitis (chronic atrophic candidiasis)? Aspergillus fumigatus Candida albicans Cryptococcus neoformans Histoplasma capsulatum Mucor species None 27. A 45-year-old patient attends for a comprehensive periodontal assessment. The clinician needs to determine the depth of the periodontal sulcus or pocket and assess the level of periodontal attachment around the teeth. Which instrument is most appropriate for this purpose? Williams periodontal probe Sickle scaler College tweezers Mouth mirror Excavator None 28. A 46-year-old patient presents with a heavily broken-down mandibular molar that has previously undergone successful root canal treatment. A substantial amount of coronal tooth structure is missing, and the tooth requires definitive restoration to reduce the risk of further fracture. Which restoration is generally most appropriate? Direct composite resin restoration Direct amalgam restoration Full-coverage crown Glass ionomer cement restoration Porcelain veneer None 29. A 32-year-old patient presents with persistent symptoms from a tooth with pulpal disease. The tooth is considered restorable, and root canal treatment is planned. What is the principal biological aim of root canal treatment? To remove all dentine from the root canal walls To eliminate or substantially reduce microorganisms and prevent reinfection of the root canal system To enlarge the apical foramen to facilitate drainage To remove the periodontal ligament surrounding the tooth To permanently strengthen the tooth against fracture None Time's up
