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Applications of Artificial Intelligence and Big Data Analytics in Orthodontics - MCQs

Test your knowledge on Applications of Artificial Intelligence and Big Data Analytics in Orthodontics (Graber 7th Edition, Chapter 9) with these 30 high-yield MCQs.

1. Which subset of Artificial Intelligence (AI) involves algorithms that improve automatically through experience and the use of data?
  • A. Expert Systems
  • B. Machine Learning (ML)
  • C. Robotics
  • D. Fuzzy Logic
Click to Reveal Answer

Correct Answer: B

Explanation: Machine Learning is the specific subset of AI where computers learn patterns from data without being explicitly programmed for every specific rule.

2. In automated cephalometric analysis, which type of Neural Network is most commonly and effectively used for landmark detection and image recognition?
  • A. Recurrent Neural Networks (RNN)
  • B. Convolutional Neural Networks (CNN)
  • C. Generative Adversarial Networks (GAN)
  • D. Radial Basis Function Networks
Click to Reveal Answer

Correct Answer: B

Explanation: CNNs are designed to process pixel data and are the gold standard in deep learning for image segmentation, classification, and landmark identification in radiographs.

3. The primary advantage of using AI for automated cephalometric landmark identification compared to manual tracing is:
  • A. Elimination of all errors
  • B. Consistency and time efficiency
  • C. Ability to function without calibration
  • D. Complete replacement of the clinician's judgment
Click to Reveal Answer

Correct Answer: B

Explanation: While AI is not error-free, its main clinical benefits are the drastic reduction in time required for analysis and the reproducibility (consistency) of the results, reducing inter-examiner variability.

4. "Big Data" in healthcare is typically characterized by the "3 Vs". These are:
  • A. Volume, Velocity, Variety
  • B. Value, Validity, Vision
  • C. Volume, Value, Velocity
  • D. Variety, Vision, Volume


Click to Reveal Answer

Correct Answer: A

Explanation: The defining characteristics of Big Data are high Volume (amount of data), high Velocity (speed of data generation), and high Variety (different types of structured and unstructured data).

5. In the context of 3D cephalometric analysis, AI is primarily used to automate which labor-intensive step?
  • A. Image acquisition (taking the CBCT)
  • B. Segmentation of anatomical structures (teeth, jaws, airway)
  • C. Patient positioning
  • D. Radiation dosing
Click to Reveal Answer

Correct Answer: B

Explanation: Segmentation (separating teeth from bone or soft tissue) is traditionally the most time-consuming part of 3D analysis. AI algorithms can automate this process with high accuracy.

6. Artificial Neural Networks (ANNs) are inspired by:
  • A. The genetic code of DNA
  • B. The biological neural networks of the human brain
  • C. Mathematical logic gates
  • D. Evolutionary biology
Click to Reveal Answer

Correct Answer: B

Explanation: ANNs consist of interconnected nodes (neurons) that process information in layers, mimicking the synaptic connections and transmission of the human brain.

7. In orthodontic treatment planning, AI decision support systems can most effectively assist with:
  • A. Predicting the exact date of debonding
  • B. Deciding between extraction vs. non-extraction based on historical data
  • C. Performing the actual extraction of teeth
  • D. Taking the final impression
Click to Reveal Answer

Correct Answer: B

Explanation: AI models trained on thousands of treated cases can identify patterns and suggest extraction/non-extraction plans that align with successful past outcomes, serving as a second opinion for the clinician.

8. Remote Treatment Monitoring (e.g., DentalMonitoring) utilizes AI primarily to:
  • A. Replace the orthodontist completely
  • B. Analyze patient-taken smartphone images to detect fit of aligners or breakage
  • C. Adjust the appliance remotely
  • D. Reduce the cost of materials
Click to Reveal Answer

Correct Answer: B

Explanation: These systems use AI to screen photos/videos taken by the patient for specific issues like aligner unseating, broken brackets, or poor hygiene, alerting the clinician only when intervention is needed.

9. "Deep Learning" (DL) differs from traditional Machine Learning (ML) in that DL:
  • A. Requires less data
  • B. Uses multiple layers of neural networks to automatically extract features
  • C. Requires manual feature extraction by experts
  • D. Is less accurate for image recognition
Click to Reveal Answer

Correct Answer: B

Explanation: Deep Learning eliminates the need for manual feature extraction. The "Deep" refers to the many hidden layers in the neural network that learn complex features directly from raw data (like pixels).

10. In the context of "Supervised Learning", the algorithm is trained using:
  • A. Unlabeled data only
  • B. Labeled data (input-output pairs)
  • C. Trial and error interaction with an environment
  • D. Random noise
Click to Reveal Answer

Correct Answer: B

Explanation: Supervised learning involves training a model on a dataset where the "correct answer" (label) is provided, such as showing the AI an x-ray and telling it "this is point A".

11. AI applications in assessment of treatment outcomes often use the "ABO Model Grading System". AI automation of this process primarily improves:
  • A. Objectivity and calibration
  • B. Subjective aesthetics
  • C. Patient satisfaction
  • D. Retention stability
Click to Reveal Answer

Correct Answer: A

Explanation: Manual grading is subjective and prone to calibration drift. AI provides a standardized, objective measurement of outcome indices (alignment, contacts, inclination).

12. Which of the following is a potential limitation or challenge of implementing AI in daily orthodontic practice?
  • A. Excessive speed of analysis
  • B. "Black Box" phenomenon (lack of explainability)
  • C. Decreased cost of software
  • D. Over-reliance on manual tracing
Click to Reveal Answer

Correct Answer: B

Explanation: The "Black Box" nature of some advanced AI models means it is difficult to understand *how* the AI arrived at a specific decision, which can be a barrier to trust and clinical acceptance.

13. In Additive Manufacturing (3D Printing), AI helps primarily by:
  • A. Mixing the resin physically
  • B. Optimizing support structures and nesting of models to save material/time
  • C. Removing the models from the build plate
  • D. Polishing the models
Click to Reveal Answer

Correct Answer: B

Explanation: AI algorithms can analyze the geometry of the 3D models to determine the most efficient orientation (nesting) and generate the minimal necessary support structures for printing.

14. The integration of AI with Genomics (GWAS) in orthodontics aims to:
  • A. Clone teeth
  • B. Predict growth patterns or susceptibility to root resorption based on genetic markers
  • C. Change the patient's DNA
  • D. Create genetically modified appliances
Click to Reveal Answer

Correct Answer: B

Explanation: AI can analyze massive genomic datasets to find correlations between specific genetic markers (SNPs) and clinical phenotypes like Class III growth tendency or risk of External Apical Root Resorption (EARR).

15. What is "Data Mining" in the context of Big Data in Orthodontics?
  • A. Deleting old patient records
  • B. Discovering patterns and knowledge from large amounts of data
  • C. Manually entering data into a spreadsheet
  • D. Encrypting patient data for security
Click to Reveal Answer

Correct Answer: B

Explanation: Data mining involves using statistical and AI techniques to uncover hidden patterns, correlations, and trends within large datasets that would not be visible to human analysis.

16. Computer Vision, a field of AI, is most applicable to which orthodontic task?
  • A. Appointment scheduling
  • B. Analyzing photographs and radiographs for diagnosis
  • C. Inventory management
  • D. Patient billing
Click to Reveal Answer

Correct Answer: B

Explanation: Computer Vision enables computers to "see" and interpret visual information from digital images or videos, making it essential for cephalometrics, facial analysis, and intraoral scanning.

17. An AI system that assesses skeletal maturation (CVM stages) from lateral cephalograms is performing a task of:
  • A. Regression
  • B. Classification
  • C. Clustering
  • D. Generation
Click to Reveal Answer

Correct Answer: B

Explanation: This is a Classification task because the AI is categorizing the input image into discrete classes (e.g., CS1, CS2, CS3, etc.) based on the shape of the vertebrae.

18. In AI-driven aligner staging, the algorithm calculates:
  • A. The cost of the treatment
  • B. The optimal amount of movement per aligner to stay within biological limits
  • C. The brand of plastic to be used
  • D. The patient's compliance level
Click to Reveal Answer

Correct Answer: B

Explanation: AI optimizes the staging (segmentation of movement) to ensure forces are applied efficiently and do not exceed the biological threshold for safe tooth movement, reducing the need for refinements.

19. Which term refers to the dataset used to evaluate the performance of an AI model *after* it has been trained?
  • A. Training set
  • B. Validation set
  • C. Test set
  • D. Feature set
Click to Reveal Answer

Correct Answer: C

Explanation: The Test set is a separate portion of data held back during training. It is used only at the end to provide an unbiased evaluation of the final model's performance on unseen data.

20. "Augmented Reality" (AR) in orthodontics, often powered by AI, allows for:
  • A. Printing 3D models
  • B. Superimposing the predicted treatment outcome over the patient's live face
  • C. Creating virtual brackets
  • D. Automating cephalometric tracing
Click to Reveal Answer

Correct Answer: B

Explanation: AR overlays digital information (like the post-treatment smile simulation) onto the real-world view (the patient's face in a mirror or camera), enhancing patient communication and motivation.

21. The main ethical concern regarding "Big Data" in orthodontics is:
  • A. Data storage space
  • B. Patient privacy and data security
  • C. The speed of internet connection
  • D. The resolution of images
Click to Reveal Answer

Correct Answer: B

Explanation: Aggregating massive amounts of patient health data raises significant concerns about anonymity, consent, and the risk of data breaches (security), which must be strictly managed (e.g., HIPAA compliance).

22. AI algorithms used for facial analysis can detect phenotypes associated with syndromes. This is an example of:
  • A. Pattern recognition
  • B. Predictive analytics
  • C. Natural Language Processing
  • D. Robotic Process Automation
Click to Reveal Answer

Correct Answer: A

Explanation: The AI identifies specific geometric patterns and ratios in the face (Pattern Recognition) that match known databases of syndromic features, aiding in early diagnosis.

23. "Natural Language Processing" (NLP) in orthodontics would be most useful for:
  • A. Detecting landmarks on a cephalogram
  • B. Extracting data from unstructured text in electronic health records (EHR)
  • C. Segmentation of teeth in an STL file
  • D. Designing a clear aligner
Click to Reveal Answer

Correct Answer: B

Explanation: NLP is the branch of AI that helps computers understand, interpret, and manipulate human language. It is used to mine clinical notes, research papers, and patient feedback.

24. What is the role of AI in "Virtual Setup" preparation?
  • A. It physically moves the teeth on the plaster model
  • B. It automates the separation and initial positioning of teeth in the digital model
  • C. It scans the impression
  • D. It prints the aligners
Click to Reveal Answer

Correct Answer: B

Explanation: AI automates the "segmentation" (identifying individual tooth boundaries) and suggests an ideal arch form setup, which the technician or orthodontist then refines.

25. A "Neural Network" is composed of input, output, and _______ layers.
  • A. Hidden
  • B. Transparent
  • C. Linear
  • D. Static
Click to Reveal Answer

Correct Answer: A

Explanation: The layers between the input and output are called "Hidden Layers". Deep learning models have many hidden layers where the complex processing and feature extraction occur.

26. In the context of AI, "Overfitting" means:
  • A. The model performs well on training data but poorly on new, unseen data
  • B. The model is too simple to capture the pattern
  • C. The model takes too long to train
  • D. The dataset is too small
Click to Reveal Answer

Correct Answer: A

Explanation: Overfitting occurs when an AI learns the "noise" or specific details of the training set too well, making it unable to generalize to new patients (poor predictive validity).

27. Which technology is essential for converting a physical dental cast into digital data for AI analysis?
  • A. 3D Printing
  • B. Intraoral or Desktop Scanning
  • C. MRI
  • D. Cephalometry
Click to Reveal Answer

Correct Answer: B

Explanation: Scanners (structured light or laser) capture the geometry of the dentition, creating the STL/PLY files that serve as the input "Big Data" for orthodontic AI applications.

28. The use of AI to predict the precise bracket position for a specific patient is an example of:
  • A. Indirect Bonding (IDB) automation
  • B. Direct Bonding
  • C. Manual Setup
  • D. Standard Edgewise Technique
Click to Reveal Answer

Correct Answer: A

Explanation: AI software in digital IDB workflows calculates the optimal bracket placement on the virtual tooth to achieve the desired tip, torque, and in-out, creating a transfer tray for clinical use.

29. The ultimate goal of integrating AI and Big Data in orthodontics is:
  • A. To increase the cost of treatment
  • B. Personalized / Precision Orthodontics
  • C. To standardize treatment for everyone
  • D. To eliminate the need for diagnosis
Click to Reveal Answer

Correct Answer: B

Explanation: By analyzing vast amounts of data (genetic, morphological, treatment response), AI enables "Precision Medicine" (or Orthodontics), tailoring the treatment specifically to the individual patient's unique biological and anatomical characteristics.

30. When an AI system assists in diagnosing "White Spot Lesions" (WSL) from intraoral photos, it is acting as a:
  • A. Therapeutic agent
  • B. Diagnostic aid / Clinical Decision Support System (CDSS)
  • C. Surgical robot
  • D. Data storage unit
Click to Reveal Answer

Correct Answer: B

Explanation: Such systems are designed to augment the clinician's capabilities (CDSS), alerting them to early signs of demineralization that might be missed, but leaving the final diagnosis and treatment decision to the human.

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Multiple choice Questions - Evidence Based Orthodontics

Test your knowledge on The Role of Evidence in Orthodontics (Graber 7th Edition, Chapter 8) with these 30 high-yield MCQs.

1. Evidence-Based Orthodontics (EBO) is best defined as the integration of:
  • A. Best research evidence and clinical expertise only
  • B. Best research evidence and patient values only
  • C. Clinical expertise and patient values only
  • D. Best research evidence, clinical expertise, and patient values/preferences
Click to Reveal Answer

Correct Answer: D

Explanation: According to Sackett et al., Evidence-Based Medicine (and Orthodontics) is the integration of the best available research evidence with clinical expertise and patient values.

2. In the hierarchy of evidence, which study design is generally considered to provide the highest level of evidence for treatment efficacy?
  • A. Case-control study
  • B. Cohort study
  • C. Randomized Controlled Trial (RCT)
  • D. Expert opinion


Click to Reveal Answer

Correct Answer: C

Explanation: RCTs are considered the gold standard for assessing treatment efficacy because randomization minimizes selection bias and confounding variables, unlike observational studies.

3. Which component of the PICO format represents the alternative treatment or standard of care being compared?
  • A. P (Patient/Population)
  • B. I (Intervention)
  • C. C (Comparison)
  • D. O (Outcome)
Click to Reveal Answer

Correct Answer: C

Explanation: PICO stands for Patient/Population, Intervention, Comparison, and Outcome. 'C' refers to the control group or alternative intervention against which the primary intervention is measured.

4. The primary purpose of "allocation concealment" in an RCT is to prevent:
  • A. Detection bias
  • B. Selection bias
  • C. Attrition bias
  • D. Performance bias
Click to Reveal Answer

Correct Answer: B

Explanation: Allocation concealment ensures that the person enrolling participants does not know which group the next patient will be assigned to, preventing them from influencing the assignment (Selection Bias).

5. A study that follows a group of patients with a specific exposure (e.g., thumb sucking) forward in time to observe an outcome (e.g., open bite) is known as a:
  • A. Case-control study
  • B. Cross-sectional study
  • C. Prospective Cohort study
  • D. Randomized clinical trial
Click to Reveal Answer

Correct Answer: C

Explanation: Cohort studies are observational studies where groups are defined by exposure status and followed longitudinally to assess outcomes. Since it looks forward in time, it is prospective.

6. Which type of bias occurs if the outcome assessors know which treatment group a patient belongs to?
  • A. Selection bias
  • B. Detection (or Observer) bias
  • C. Attrition bias
  • D. Publication bias
Click to Reveal Answer

Correct Answer: B

Explanation: Detection bias (or observer bias) arises when the person measuring the outcome is influenced by their knowledge of the intervention. Blinding of assessors mitigates this.

7. In a meta-analysis, the "Forest plot" graphically displays:
  • A. The randomization process
  • B. The results of individual studies and the pooled estimate
  • C. The risk of bias in each study
  • D. The publication date of studies
Click to Reveal Answer

Correct Answer: B

Explanation: A forest plot shows the effect estimates and confidence intervals for each included study (usually as squares with lines) and the overall combined result (usually as a diamond at the bottom).

8. If the 95% Confidence Interval (CI) for a mean difference includes the value "0", this implies:
  • A. The result is statistically significant
  • B. The result is not statistically significant
  • C. The sample size was too small
  • D. There is a large treatment effect
Click to Reveal Answer

Correct Answer: B

Explanation: For continuous data (mean difference), if the CI crosses 0 (the line of no effect), it means there is no statistically significant difference between the groups at the chosen level (p > 0.05).

9. Heterogeneity in a systematic review refers to:
  • A. Variability in the results of the included studies
  • B. Similarity in study designs
  • C. The use of different statistical software
  • D. The bias present in the review process
Click to Reveal Answer

Correct Answer: A

Explanation: Heterogeneity describes the variation in study outcomes. It can be clinical (different populations/treatments) or statistical (variability in data beyond chance), often measured by the I² statistic.

10. Which study design is most prone to "recall bias"?
  • A. RCT
  • B. Prospective Cohort study
  • C. Case-control study
  • D. Laboratory study
Click to Reveal Answer

Correct Answer: C

Explanation: Case-control studies are retrospective. Participants (cases) are asked to remember past exposures, and those with the condition may remember differently than those without (controls), leading to recall bias.

11. The "diamond" shape at the bottom of a forest plot represents:
  • A. The result of the largest study
  • B. The weighted mean difference of the control group
  • C. The pooled (combined) effect estimate of all studies
  • D. The point of no significance
Click to Reveal Answer

Correct Answer: C

Explanation: The diamond represents the overall result of the meta-analysis. Its width represents the confidence interval of the pooled estimate.

12. "Attrition bias" in a longitudinal study is caused by:
  • A. Poor randomization
  • B. Loss of participants (dropouts) during the study
  • C. Inaccurate measurement tools
  • D. Funding source influence
Click to Reveal Answer

Correct Answer: B

Explanation: Attrition bias occurs when participants who drop out of the study differ systematically from those who remain, potentially skewing the results (e.g., if treatment failures drop out).

13. Which of the following is a "secondary" source of evidence?
  • A. Randomized Controlled Trial
  • B. Systematic Review
  • C. Cohort Study
  • D. Case Series
Click to Reveal Answer

Correct Answer: B

Explanation: Systematic reviews (and meta-analyses) are secondary research because they filter, synthesize, and analyze primary research studies (like RCTs and Cohorts).

14. The main limitation of a "cross-sectional study" is its inability to:
  • A. Measure prevalence
  • B. Establish causality (temporal sequence)
  • C. Be conducted quickly
  • D. Study multiple variables
Click to Reveal Answer

Correct Answer: B

Explanation: Cross-sectional studies measure exposure and outcome at the same single point in time ("snapshot"). Therefore, you cannot determine if the exposure preceded the outcome (causality).

15. To minimize "performance bias", a study should ideally be:
  • A. Randomized
  • B. Double-blinded
  • C. Multi-centered
  • D. Large in sample size
Click to Reveal Answer

Correct Answer: B

Explanation: Performance bias occurs if patients or clinicians behave differently because they know who is in which group. Blinding (masking) both parties prevents this.

16. The CONSORT statement is a guideline used for reporting:
  • A. Observational studies
  • B. Systematic reviews
  • C. Randomized Controlled Trials
  • D. Case reports
Click to Reveal Answer

Correct Answer: C

Explanation: CONSORT (Consolidated Standards of Reporting Trials) provides an evidence-based set of recommendations for reporting randomized trials to ensure transparency.

17. In statistical hypothesis testing, the p-value represents:
  • A. The probability that the results are due to chance assuming the null hypothesis is true
  • B. The probability that the alternative hypothesis is true
  • C. The clinical significance of the finding
  • D. The power of the study
Click to Reveal Answer

Correct Answer: A

Explanation: The p-value measures the strength of evidence against the null hypothesis. A low p-value (typically < 0.05) indicates that the observed data would be unlikely if there were truly no effect.

18. Which database is considered the premier source for Systematic Reviews?
  • A. PubMed
  • B. Google Scholar
  • C. The Cochrane Library
  • D. Embase
Click to Reveal Answer

Correct Answer: C

Explanation: The Cochrane Library is renowned for producing high-quality, independent systematic reviews used to inform healthcare decision-making.

19. What is "publication bias"?
  • A. Studies with positive/significant results are more likely to be published than negative ones
  • B. Bias introduced by the funding agency
  • C. Bias in the statistical analysis of data
  • D. Reviewers rejecting papers based on author reputation
Click to Reveal Answer

Correct Answer: A

Explanation: This is a major issue where "negative" studies (showing no difference) often remain unpublished (the "file drawer" problem), causing systematic reviews to overestimate treatment effects.

20. The PRISMA statement provides guidelines for reporting:
  • A. RCTs
  • B. Systematic Reviews and Meta-Analyses
  • C. Observational studies
  • D. Animal studies
Click to Reveal Answer

Correct Answer: B

Explanation: PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) is the standard checklist and flow diagram used to report systematic reviews.

21. In an RCT, "Intention-to-Treat" (ITT) analysis means:
  • A. Analyzing only patients who completed the full treatment protocol
  • B. Analyzing patients in the groups they were originally randomized to, regardless of adherence
  • C. Excluding dropouts from the final analysis
  • D. Analyzing based on the treatment actually received
Click to Reveal Answer

Correct Answer: B

Explanation: ITT preserves the benefits of randomization. By analyzing everyone in their original groups (even if they switched or dropped out), it provides a more realistic (pragmatic) estimate of effectiveness.

22. An "I-squared" (I²) value of 0% in a meta-analysis suggests:
  • A. High heterogeneity
  • B. Moderate heterogeneity
  • C. No observed heterogeneity
  • D. Significant publication bias
Click to Reveal Answer

Correct Answer: C

Explanation: I² ranges from 0% to 100%. A value of 0% indicates that the variation across studies is likely due to chance alone (consistency), whereas high values (>75%) suggest considerable heterogeneity.

23. Which level of evidence is traditionally at the base (lowest level) of the evidence pyramid?
  • A. Case Series
  • B. Animal research / In vitro studies
  • C. Expert opinion / Editorials
  • D. Cross-sectional studies
Click to Reveal Answer

Correct Answer: B

Explanation: While Expert Opinion is the lowest form of clinical evidence involving humans, foundational research like animal or lab studies sits at the very bottom, as findings often do not translate directly to humans.

24. A "confounding variable" is a factor that:
  • A. Is the main outcome of interest
  • B. Distorts the association between exposure and outcome
  • C. Is used to randomize patients
  • D. Is removed during blinding
Click to Reveal Answer

Correct Answer: B

Explanation: A confounder is associated with both the exposure and the outcome (e.g., age or smoking status) and can make it look like there is a relationship when there isn't, or mask a true relationship.

25. Which risk of bias tool is most commonly used for assessing Randomized Controlled Trials?
  • A. ROBINS-I
  • B. Newcastle-Ottawa Scale
  • C. Cochrane Risk of Bias tool (RoB 2)
  • D. QUADAS-2
Click to Reveal Answer

Correct Answer: C

Explanation: The Cochrane Risk of Bias tool (RoB 2) is the standard for RCTs. ROBINS-I and Newcastle-Ottawa are used for observational/non-randomized studies.

26. A 95% Confidence Interval (CI) implies that if the study were repeated 100 times:
  • A. The true population value would lie within this range 95 times
  • B. 95% of the patients will improve
  • C. The result is 95% correct
  • D. There is a 5% chance of bias
Click to Reveal Answer

Correct Answer: A

Explanation: A CI is a range of values that likely contains the true population parameter. It indicates the precision of the estimate.

27. Which of the following is an example of a "Patient-Reported Outcome Measure" (PROM)?
  • A. Cephalometric ANB angle
  • B. Little's Irregularity Index
  • C. Oral Health-Related Quality of Life (OHRQoL)
  • D. Bond failure rate
Click to Reveal Answer

Correct Answer: C

Explanation: PROMs capture the patient's perspective on their health status. OHRQoL scores (like CPQ or OHIP) measure the impact of oral health on daily life, unlike clinician-measured angles or indices.

28. The "Null Hypothesis" (H0) generally states that:
  • A. The experimental treatment is superior
  • B. There is no difference between the groups being compared
  • C. The study has low power
  • D. The results are biased
Click to Reveal Answer

Correct Answer: B

Explanation: The null hypothesis is the default position that there is no relationship between two measured phenomena or no difference among groups.

29. When searching for evidence, using "AND" between two search terms (e.g., "Orthodontics AND Corticotomy"):
  • A. Broadens the search to include articles with either term
  • B. Narrows the search to include only articles with both terms
  • C. Excludes the second term
  • D. Finds synonyms for both terms
Click to Reveal Answer

Correct Answer: B

Explanation: Boolean operator "AND" is used to refine/narrow a search, ensuring that the results must contain both keywords.

30. Why is randomization essential in clinical trials?
  • A. To ensure the sample size is large enough
  • B. To balance known and unknown confounders between groups
  • C. To ensure patients do not know their treatment allocation
  • D. To make statistical analysis easier
Click to Reveal Answer

Correct Answer: B

Explanation: The unique power of randomization is that it creates comparable groups by distributing both known (measured) and unknown (unmeasured) confounding variables equally, isolating the treatment effect.

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Clinically Relevant Aspects of Dental Materials Science in Orthodontics - Multiple choice questions In Orthodontics

Test your knowledge on Clinically Relevant Aspects of Dental Materials Science in Orthodontics (Graber 7th Edition) with these 35 high-yield MCQs.



1. The stiffness (elastic modulus) of a stainless steel bracket is clinically most relevant to which mechanic?
  • A. Friction during sliding mechanics
  • B. Bond strength to enamel
  • C. Torque expression
  • D. Corrosion resistance
Click to Reveal Answer

Correct Answer: C

Explanation: Stiffness determines the bracket's resistance to deformation. During torque application with rectangular wires, a bracket with low stiffness may experience elastic deformation (slot widening), which significantly reduces the effective torque delivered to the tooth.

2. Which feature of a stainless steel bracket slot surface has the greatest impact on increasing resistance to sliding (friction)?
  • A. High polish
  • B. Increased surface roughness
  • C. Reduced slot depth
  • D. Increased hardness
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Thumb sucking is considered as emotional disturbance according to which psychological study?

 # Thumb sucking is considered as emotional disturbance according to which psychological study?
A. Classical conditioning
B. Operant conditioning
C. Freudian theory
D. Pavlov Theory



The correct answer is C. Freudian theory.

In Freudian psychoanalytic theory, thumb sucking is viewed as an oral-stage fixation or regression, stemming from unresolved emotional conflicts or disturbances during infancy, where sucking provides instinctual gratification but persists as a self-soothing mechanism indicative of underlying anxiety or unmet needs. This contrasts with classical conditioning (Pavlov's theory, option D) focused on stimulus-response associations, operant conditioning (option B) on reinforcement of behaviors, and lacks direct ties to emotional disturbance in those frameworks. Modern views often see it as normal self-soothing, but Freud's perspective pathologizes prolonged habits as symptomatic of psychosexual development issues.


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Keen’s approach is used to elevate zygomatic arch:

 # Keen’s approach is used to elevate zygomatic arch:
A. Extraorally
B. Intraorally
C. Transbuccally
D. Percutaneous route



The correct answer is B. Intraorally

Keen’s approach is a closed reduction technique for isolated zygomatic arch fractures, performed via an intraoral incision in the maxillary buccal vestibule (upper gingival sulcus), allowing indirect elevation with a Rowe's disimpaction forceps or similar instrument inserted through the incision to access and lift the depressed arch. This method minimizes visible scarring, avoids facial nerve risk, and prevents external incisions, though it requires careful closure to avoid complications like oroantral fistula. It contrasts with extraoral approaches (e.g., Gillies temporal), percutaneous stab incisions (e.g., for screws), or transbuccal punctures.

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Growth of maxilla in the vertical direction is due to:

 # Growth of maxilla in the vertical direction is due to:
A. Growth of alveolus
B. Growth of sutures
C. Growth of cranial base
D. Growth of synchondrosis



The correct answer is B. Growth of sutures

Vertical growth of the maxilla occurs primarily through inferior displacement facilitated by bone apposition and remodeling at the circum-maxillary sutures (e.g., fronto-maxillary, zygomatico-maxillary, and spheno-maxillary sutures), allowing the maxilla to elongate downward while adapting to surrounding structures like the expanding nasal septum and orbital contents. This mechanism accounts for the majority of vertical maxillary development from infancy through adolescence, with contributions from alveolar apposition around erupting teeth but not as the primary driver. Cranial base growth (via synchondroses) contributes indirectly by providing anteroposterior expansion that influences displacement, but sutural growth is the direct enabler of vertical changes, as supported by classic orthodontic principles (e.g., Enlow's remodeling concepts and Björk's implant studies showing downward vector at ~51° to the cranial base).


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Additional parameter in five characteristics of Ackerman-Proffit Classification?

 # Which is added as an additional parameter in five characteristics of Ackerman-Proffit Classification?
A. Curve of Spee
B. Esthetic line of occlusion
C. Smile arc
D. Smile line


The correct answer is B. Esthetic line of occlusion

The Ackerman-Proffit classification evaluates malocclusion using Angle's anteroposterior relationships plus five key characteristics—alignment (perimeter/crowding), transverse relationship (arch width discrepancies), vertical relationship (open/deep bite), overjet (incisor protrusion), and midline deviation (asymmetry)—often visualized via a Venn diagram for comprehensive diagnosis. To enhance esthetic analysis, the esthetic line of occlusion is incorporated as an additional parameter, assessing the curved alignment of the maxillary incisor edges relative to the lower lip during smiling or repose, which helps predict treatment outcomes for facial harmony beyond functional aspects. This addition addresses limitations in purely skeletal classifications by integrating soft-tissue esthetics. Options A (Curve of Spee) relates to occlusal curvature but isn't added here; C (Smile arc) and D (Smile line) are related esthetic features but not specifically the parameter in this system.

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Gene therapy targeting the germ-line is:

 # Gene therapy targeting the germ-line is:
A. Heritable
B. Non heritable
C. Sometimes heritable
D. Unrelated to heritability



The correct answer is: A. Heritable

Germ-line gene therapy involves modifying DNA in germ cells (sperm, ova, or their precursors), which integrate into the genome and are transmitted to future generations, making the genetic changes heritable. This contrasts with somatic gene therapy, which targets non-reproductive cells and is non-heritable (option B). Option C is incorrect as heritability is inherent to germ-line targeting, and option D is irrelevant since heritability is the defining feature. Ethical and regulatory concerns limit germ-line therapy in humans, but the biological principle remains clear.

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Raw erythematous areas with bleeding spots on a boy with juvenile diabetes mellitus

 # A 9 year old boy visited OPD for soreness in the mouth. He had history of juvenile diabetes mellitus and was on insulin therapy. On intraoral examination, a large white scrapable lesion was noted on the soft palate. Raw erythematous areas with bleeding spots were seen after scraping the lesion. What is the most likely diagnosis to be?
A. Diphtheria
B. Oral Thrush
C. White Spongy Nevus
D. Vincent’s stomatitis
E. Chronic Hyperplastic Candidiasis


The correct answer is B. Oral Thrush

Oral thrush (pseudomembranous candidiasis) is the most likely diagnosis, characterized by white, creamy plaques on mucosal surfaces like the soft palate that scrape off easily, revealing underlying erythematous, raw tissue prone to bleeding—directly matching the presentation. Juvenile diabetes mellitus predisposes to this via hyperglycemia impairing immune response and promoting Candida albicans overgrowth, common in children on insulin. Diagnosis is clinical, confirmed by microscopy if needed (hyphae in KOH prep). Treatment involves topical antifungals (e.g., nystatin suspension) and glycemic control; systemic options if refractory. Other options are less fitting: diphtheria involves adherent gray membranes with systemic toxicity; white spongy nevus is non-scrapable and hereditary; Vincent’s stomatitis targets interdental gingiva with necrosis; chronic hyperplastic candidiasis forms adherent, non-scrapable plaques.


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Which of the following is an accessory cusp found on a mandibular molar?

 # Which of the following is an accessory cusp found on a mandibular molar?
A. Protostylid
B. Cusp of Carabelli
C. Dens Evaginatus
D. Paramolar cusp


The correct answer is A. Protostylid

The protostylid is a supernumerary accessory cusp located on the mesiobuccal surface of mandibular molars, often appearing as a pit, groove, or distinct tubercle that can vary in expression from mild to pronounced. In contrast, the cusp of Carabelli (option B) is an accessory feature on the mesiolingual surface of maxillary first molars; dens evaginatus (option C) typically presents as an occlusal tubercle on premolars (especially mandibular second premolars), though it can rarely affect molars; and the paramolar cusp (option D), also known as Bolk's cusp, is primarily an extra tubercle on the buccal surface of maxillary molars. 
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Three days after the onset of myocardial infarction which enzyme level has the best predictive value?

 # Three days after the onset of myocardial infarction which enzyme level has the best predictive value?
A. Serum CPK
B. Serum LDH
C. Serum SGOT
D. Serum SGPT



The correct answer is B. Serum LDH

Lactate dehydrogenase (LDH) levels rise 12-24 hours after myocardial infarction (MI), peak at 48-72 hours (around day 3), and remain elevated for 7-14 days, providing the highest diagnostic sensitivity and predictive value for confirming MI at this late stage. In contrast, creatine phosphokinase (CPK) peaks early (12-24 hours) and normalizes by day 3, making it less useful then; serum glutamic-oxaloacetic transaminase (SGOT/AST) peaks at 24-48 hours and declines by day 3-4; and serum glutamic-pyruvic transaminase (SGPT/ALT) is primarily liver-specific with minimal cardiac relevance. The LDH-1 isoenzyme is particularly specific for cardiac tissue damage.

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Which of the following is an occupational disease of dentist?

 # Which of the following is an occupational disease of dentist?
A. Syphilis
B. HIV
C. HBV
D. All of the above



The correct answer is D. All of the above

Dentists face occupational risks from bloodborne pathogens due to exposure via needlestick injuries, cuts, splashes, or aerosols during procedures. HBV (hepatitis B virus) is highly transmissible and a major concern, with vaccination recommended. HIV (human immunodeficiency virus) has lower infectivity but remains a risk. Syphilis (Treponema pallidum) can spread through contact with infectious oral lesions or blood. OSHA and CDC guidelines classify all three as occupational hazards for dental professionals, emphasizing universal precautions, PPE, and post-exposure protocols to mitigate transmission.


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Ideal period for surgical correction of maxilla and mandible:

 # Ideal period for surgical correction of maxilla and mandible:
A. Early growth spurts
B. Mid growth spurts
C. Late growth spurts
D. After cessation of growth spurts


The correct answer is D. After cessation of growth spurts.

Orthognathic surgery for correcting maxillary and mandibular discrepancies is ideally performed after skeletal growth has ceased to minimize postoperative relapse due to residual growth. This typically occurs in late adolescence or early adulthood (around 16-18 years for females and 18-21 years for males), once pubertal growth spurts are complete and facial bones have stabilized. Earlier interventions during active growth phases (options A-C) risk instability and require potential revisions. Preoperative orthodontics (12-18 months) aligns teeth for optimal surgical outcomes, followed by postoperative orthodontics for refinement. 
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2 month baby having ulceration of tongue

 # Mother presents with a 2 month old baby having ulceration of tongue in relation to erupted tooth in mandibular incisor region. Treatment: 
A. Extraction
B. Prescribe local anesthetic gel
C. Radiograph to confirm presence of deciduous tooth followed by rounding of incisal edges
D. Counsel mother and recall


The correct answer is C. Radiograph to confirm presence of deciduous tooth followed by rounding of incisal edges

This case likely involves Riga-Fede disease, a traumatic ulceration of the tongue caused by the sharp incisal edges of a natal or neonatal tooth (typically a mandibular primary central incisor) in an infant. At 2 months old, tooth eruption is premature, so confirming it's a deciduous tooth via radiograph is essential to rule out anomalies like supernumerary teeth. The primary treatment is conservative: smoothing or rounding the incisal edges to eliminate the trauma source, allowing the ulcer to heal spontaneously (often within 1-4 weeks). Extraction (option A) is reserved for highly mobile teeth or severe feeding interference, not routine here. Local anesthetic gel (option B) offers only temporary symptom relief without addressing the cause. Counseling and recall (option D) suit asymptomatic cases but not active ulceration. Follow-up is recommended post-treatment to monitor healing and eruption.
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In comparison with the permanent mandibular canine, the permanent maxillary canine in the same mouth:

 # In comparison with the permanent mandibular canine, the permanent maxillary canine in the same mouth:
a) Has a shorter root
b) Is wider mesiodistally
c) Is narrower mesiodistally
d) Has a less pronounced cingulum



The correct answer is b) Is wider mesiodistally

The permanent maxillary canine is wider mesiodistally than the permanent mandibular canine in the same mouth, with typical crown measurements of about 7.5 mm for the maxillary canine compared to 7.0 mm for the mandibular canine. In contrast, the maxillary canine has a longer root (around 17 mm versus 16.5 mm for the mandibular), and its cingulum is more developed and prominent on the lingual surface than the mandibular canine's.
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16th International Orthodontic Conference of ODOAN 2025 - Pre Conference Workshop Photos


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