Forensic Odontology Practice Questions

Q: According to the Federation Dentaire Internationale (FDI) notation, what is the designation for the lower left canine?

33. The **Federation Dentaire Internationale (FDI)** system is the most widely used dental notation method globally. It uses a two-digit system where the first digit represents the **quadrant** and the second digit represents the **tooth position** from the midline. ### 1. Why Option B (33) is Correct: * **Quadrant (First Digit):** The mouth is divided into four quadrants (clockwise from the patient's perspective): * 1: Upper Right * 2: Upper Left * **3: Lower Left** * 4: Lower Right * **Tooth Position (Second Digit):** Teeth are numbered 1 to 8 starting from the central incisor: * 1: Central Incisor | 2: Lateral Incisor | **3: Canine** | 4: 1st Premolar | 5: 2nd Premolar | 6: 1st Molar | 7: 2nd Molar | 8: 3rd Molar. * Combining these, the **Lower Left (3)** **Canine (3)** is designated as **33**. ### 2. Analysis of Incorrect Options: * **A. 32:** Represents the Lower Left Lateral Incisor (Quadrant 3, Position 2). * **C. 42:** Represents the Lower Right Lateral Incisor (Quadrant 4, Position 2). * **D. 43:** Represents the Lower Right Canine (Quadrant 4, Position 3). ### 3. High-Yield Clinical Pearls for NEET-PG: * **Deciduous Teeth:** In the FDI system, primary (milk) teeth use quadrant numbers **5 to 8** (5: Upper Right, 6: Upper Left, 7: Lower Left, 8: Lower Right). For example, the lower left deciduous canine is **73**. * **Gustafson’s Method:** The most reliable method for age estimation in adults using teeth, involving six parameters (Attrition, Periodontitis, Secondary dentin, Cementum apposition, Root resorption, and Transparency of dentin). * **Keiser-Nielsen Criteria:** Used for forensic dental identification, requiring at least 12 points of concordance between antemortem and postmortem records. * **Canine Index:** Used for sex determination; the mandibular canine is the most dimorphic tooth.

Q: Which of the following is the most reliable criterion in Gustafson's method of identification?

Transparency of root. **Explanation:** Gustafson’s Method (1950) is a widely used technique in forensic odontology for estimating the age of an individual based on age-related changes in the teeth. It utilizes a point system (0 to 3) across six specific parameters. **Why "Transparency of Root" is the correct answer:** Among the six criteria, **Root Transparency (Sclerosis)** is considered the **most reliable and accurate** indicator of age. This phenomenon occurs due to the gradual deposition of minerals within the dentinal tubules, starting from the apical end and moving coronally. Unlike other factors, it is least affected by external environmental factors, pathological conditions (like caries), or functional stress, making it a stable physiological marker of aging. **Analysis of Incorrect Options:** * **A. Attrition:** This refers to the wearing down of the occlusal surface. It is highly variable as it depends heavily on diet, chewing habits (bruxism), and the loss of opposing teeth. * **B. Cementum Apposition:** This is the continuous deposition of cementum at the root apex. While it increases with age, it can be pathologically altered by local inflammation or systemic metabolic disorders. * **D. Root Resorption:** This is the most variable and least reliable of the six parameters. It is often influenced by local pressure, orthodontic movements, or idiopathic factors rather than just chronological age. **High-Yield Facts for NEET-PG:** * **The Six Parameters (Mnemonic: ASCEND):** **A**ttrition, **S**econdary dentin deposition, **C**ementum apposition, **E**xternal root resorption, **N**eck retraction (Periodontosis), and **D**entinal transparency. * **Formula:** Age = 11.43 + 4.56 (Total Score). * **Secondary Dentin:** This is the second most reliable parameter after root transparency. * **Applicability:** This method is most accurate for individuals over the age of 21.

Q: Teeth bite marks are a type of:

Pressure abrasion. **Explanation:** **Why Pressure Abrasion is Correct:** Bite marks are unique mechanical injuries caused by the teeth of humans or animals. When teeth are pressed against the skin without significant lateral movement, they cause a vertical crushing of the superficial layers of the epidermis. This results in a **pressure abrasion** (also known as a crush abrasion), which accurately mirrors the occlusal surfaces of the teeth. While bite marks often present as a complex injury (a combination of abrasions, contusions, and sometimes lacerations), the primary diagnostic feature used for forensic dental identification is the pressure abrasion. **Why Other Options are Incorrect:** * **Contusion (Bruise):** While suction or the impact of teeth can cause bruising (ecchymosis), a contusion alone lacks the sharp structural detail of the dental margins required for forensic matching. * **Graze (Sliding Abrasion):** This occurs when the skin surface is scraped by friction. In a bite mark, this would only occur if there was significant "slippage," which usually distorts the mark rather than defining it. * **Linear Abrasion:** These are "scratches" caused by a sharp point drawn across the skin. Teeth generally produce curved or patterned marks rather than simple linear ones. **High-Yield Clinical Pearls for NEET-PG:** * **Forensic Significance:** Bite marks are considered "individualistic" evidence, similar to fingerprints. * **Common Sites:** In females, they are most commonly found on the breasts and legs (sexual assault); in males, on the arms and shoulders (offensive/defensive). * **DNA Recovery:** Always swab the area for **salivary amylase** and epithelial cells for DNA profiling before cleaning the wound. * **Photography:** Use a **scale (ABFO No. 2)** to ensure 1:1 ratio for forensic comparison.

Question 1

The term dilaceration refers to what?

Accepted Answer

A deformity of a tooth consisting of a sharp bend in the root

Answer

Abrasions on two surfaces of a single tooth

Answer

A root or tooth that is split into two

Answer

A tooth that is fractured at two or more places

Question 2

According to the Federation Dentaire Internationale (FDI) notation, what is the designation for the lower left canine?

Accepted Answer

33

Answer

32

Answer

42

Answer

43

Question 3

Which of the following is the most reliable criterion in Gustafson's method of identification?

Accepted Answer

Transparency of root

Answer

Attrition

Answer

Cementum apposition

Answer

Root resorption

Question 4

Teeth bite marks are a type of:

Accepted Answer

Pressure abrasion

Answer

Contusion

Answer

Graze

Answer

Linear abrasion

Forensic Odontology — MCQs

Forensic Odontology — MCQs

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