Sex Determination from Dental Features — MCQs
Which index is used to evaluate palatal height?
True statement about the skull shown below:
Crown completion of the mandibular canine occurs
Ratio of mesiodistal width to height of the crown of the maxillary canine is
Best site for DNA extraction from a 2-month-old decomposed body?
Which banding technique is most commonly used for karyotyping?
The most reliable method of identification of an individual is:
Which of the following is used for sex chromatin testing?
Best method to evaluate bone defect is
Preauricular sulcus is useful for determination of:
Sex Determination from Dental Features Indian Medical PG Practice Questions and MCQs
Question 1: Which index is used to evaluate palatal height?
- A. Moyers' Palatal Height Index (Correct Answer)
- B. Hixon and Oldfather's Index
- C. Korakhaus Index
- D. Bolton's Analysis
Explanation: ***Moyers' Palatal Height Index*** - While **Moyers' Index** is well-known in orthodontics, it is primarily associated with **mixed dentition analysis** for predicting the size of unerupted canines and premolars. - The term "Palatal Height Index" (or Palatal Index) typically refers to the ratio: **(Palatal Height / Palatal Width) × 100**, used to assess palatal vault morphology. - Some literature may reference variations in terminology, though classical Moyers' work focused on tooth size prediction. *Hixon and Oldfather's Index* - **Hixon and Oldfather's Index** is used for predicting the size of unerupted canines and premolars based on the width of mandibular incisors. - It focuses on tooth size prediction in mixed dentition analysis. *Korkhaus Index* - The **Korkhaus Index** is used in orthodontics for analyzing **arch length** and determining space requirements. - Formula: Sum of mesiodistal widths of incisors × 100 / arch length - Not directly used for palatal height measurement. *Bolton's Analysis* - **Bolton's Analysis** evaluates the proportional relationship between maxillary and mandibular tooth sizes. - It identifies **tooth size discrepancies** between upper and lower arches (anterior ratio: 77.2% ± 1.65%; overall ratio: 91.3% ± 1.91%). - Does not measure palatal height.
Question 2: True statement about the skull shown below:
- A. Round shaped orbit, prominent frontal eminences - Female
- B. Round shaped orbit, prominent frontal eminences - Male
- C. Prominent supraorbital ridges, prominent glabella, square chin, acute fronto-nasal angle - Male (Correct Answer)
- D. Prominent supraorbital ridges, prominent glabella, square chin, acute fronto-nasal angle - Female
Explanation: ***Prominent supraorbital ridges, prominent glabella, square chin, acute fronto-nasal angle - Male*** - The image displays features typical of a **male skull**, including a pronounced **supraorbital ridge** (brow ridge), a prominent **glabella** (area between the eyebrows), a more **square and robust chin**, and an **acute fronto-nasal angle**. - These characteristics reflect the usually heavier and denser bone structure in males, adapted for stronger muscle attachments. *Round shaped orbit, prominent frontal eminences - Female* - **Female skulls generally have rounder orbits** and more prominent frontal eminences, giving the forehead a fuller, more rounded appearance. - The skull in the image does not exhibit these characteristics; the orbits are squarer, and the frontal eminences are not particularly prominent. *Prominent supraorbital ridges, prominent glabella, square chin, acute fronto-nasal angle - Female* - This statement incorrectly attributes features typically found in **male skulls** to a female skull. - Female skulls are generally smoother and less rugged, lacking the prominently developed ridges and angles seen in the image. *Round shaped orbit, prominent frontal eminences - Male* - This statement incorrectly attributes features typical of **female skulls** to a male skull. - Male skulls usually have squarer orbits and less prominent frontal eminences, with a more sloping forehead compared to females.
Question 3: Crown completion of the mandibular canine occurs
- A. At birth
- B. 11-12 years
- C. 8-9 years
- D. 4-5 years (Correct Answer)
Explanation: ***4-5 years*** - The permanent mandibular canine crown typically completes its formation between **4 to 5 years of age**. - This timing is crucial for understanding the **developmental chronology** of permanent dentition. *At birth* - At birth, only the crowns of the **deciduous (primary) teeth** are forming or nearing completion, not permanent teeth like the mandibular canine. - The formation of permanent tooth crowns generally begins later in infancy or early childhood. *11-12 years* - By **11-12 years of age**, the crown of the permanent mandibular canine would have been completed for several years, and the tooth is usually in the process of **erupting** or has already erupted into the oral cavity. - Root completion for the mandibular canine typically occurs around this age (12-14 years), not crown completion. *8-9 years* - While other permanent teeth like incisors might be erupting or completing their crowns around **8-9 years of age**, the mandibular canine crown has usually finished forming several years prior. - This age range typically sees the eruption of the mandibular canines, but not their crown completion.
Question 4: Ratio of mesiodistal width to height of the crown of the maxillary canine is
- A. 7:10
- B. 8:10 (Correct Answer)
- C. 10:08
- D. 8:06
Explanation: ***8:10*** - The ratio of the **mesiodistal width** to the **cervico-incisal height** of the crown of a **maxillary canine** is approximately 8:10. - This indicates that the **crown is taller than it is wide**, a characteristic feature of canine morphology. *10:08* - This ratio suggests the **mesiodistal width is greater than the height**, which is not typical for a maxillary canine crown. - Canines are known for their **long, pointed crowns**, making them taller than they are wide. *7:10* - While this ratio also indicates the crown is taller than it is wide, it is **not the most accurate or commonly accepted ratio** for maxillary canine dimensions. - The **anatomical average** for maxillary canine crown dimensions more closely aligns with an 8:10 proportion. *8:06* - This ratio implies the **mesiodistal width is significantly greater than the height**, which is incorrect for a canine. - This proportion would describe a **much wider and shorter crown**, unlike the characteristic form of a maxillary canine.
Question 5: Best site for DNA extraction from a 2-month-old decomposed body?
- A. Muscle
- B. Bone
- C. Teeth (Correct Answer)
- D. Hair
Explanation: ***Teeth*** - Teeth, particularly the **pulp and dentin**, provide a highly protected environment for DNA, making them ideal for DNA extraction from **decomposed remains** due to their robust structure. - The hard enamel casing shields the internal DNA from environmental degradation and microbial contamination, allowing for excellent preservation over extended periods. - **Dental pulp** is consistently reliable and easily accessible, making teeth the **preferred first choice** in forensic DNA extraction from decomposed bodies. *Bone* - **Bone**, particularly the **petrous portion of the temporal bone** and long bones, is also an **excellent source** of DNA in decomposed remains and is widely used in forensic practice. - However, DNA extraction from bone requires more extensive processing (demineralization, grinding) compared to teeth, making it a **second-line choice** when teeth are available. - The petrous temporal bone is notably resistant to degradation, but teeth remain more practically accessible. *Muscle* - **Muscle tissue** contains significant DNA when fresh, but is highly susceptible to **autolysis and bacterial degradation** in a decomposed body. - As decomposition progresses over 2 months, muscle tissue breaks down rapidly, reducing both the quantity and quality of recoverable DNA significantly. *Hair* - **Hair shafts** primarily contain mitochondrial DNA (mtDNA) with minimal nuclear DNA, which limits their use for individual identification. - Hair roots (if present) contain nuclear DNA, but in decomposed remains, hair is often shed or degraded, making it an unreliable source compared to teeth.
Question 6: Which banding technique is most commonly used for karyotyping?
- A. G banding (Correct Answer)
- B. Q banding
- C. C banding
- D. R banding
Explanation: ***G banding*** - This method is the **most widely used** technique for karyotyping, allowing clear visualization of chromosome bands under light microscopy [1][2]. - G banding helps in identifying **chromosomal abnormalities** and is routinely utilized in clinical genetics [2]. *C banding* - Primarily highlights the **centromeric regions** of chromosomes, but is less common than G banding for overall karyotyping. - Does not provide a full **karyotype view**, making it less suitable for routine analysis. *R banding* - Useful for providing **reverse staining**, which shows the bands in a different manner but is not as commonly employed in clinical settings. - Typically used to analyze specific **chromosomal translocations**, rather than routine karyotyping. *Q banding* - This technique involves **fluorescent microscopy** to visualize chromosomes but is not as prevalent for basic karyotyping. - Mainly used for detecting **specific chromosomal anomalies**, not the standard karyotype assessment. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 54-55. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Genetic Disorders, pp. 167-168.
Question 7: The most reliable method of identification of an individual is:
- A. Historical anthropometric system
- B. Fingerprint-based identification system (Correct Answer)
- C. Dental age estimation method
- D. Physical marks on the body
Explanation: ***Fingerprint-based identification system*** - **Fingerprints** are unique to each individual, including identical twins, and remain unchanged throughout life from birth to death (unless destroyed by injury or disease), making them the most reliable method for identification in forensic practice. - The distinctive patterns of **ridges and valleys** (loops, whorls, and arches) on the fingertips provide an unparalleled level of specificity and permanence. - Fingerprints are **easily collected, classified, and stored**, with well-established databases (AFIS - Automated Fingerprint Identification System) for comparison. - Even after decomposition, fingerprints can often be recovered from remains, making them valuable in disaster victim identification. *Historical anthropometric system* - **Anthropometric measurements** (Bertillon system) used body measurements like height, arm length, and head size for identification. - This method is now **obsolete** as measurements can be similar between individuals and change with age, growth, or weight changes. - It lacks the **uniqueness and permanence** required for reliable individual identification and was replaced by fingerprinting in the early 20th century. *Dental age estimation method* - **Dental age estimation** primarily assesses an individual's age based on tooth development, eruption patterns, and wear, not specific individual identity. - While **dental records** (odontology) can be excellent for identification when ante-mortem records are available for comparison, dental age estimation alone does not identify a specific individual. - Useful in mass disasters and when fingerprints are unavailable, but requires pre-existing dental records for comparison. *Physical marks on the body* - **Physical marks** such as scars, tattoos, birthmarks, or deformities can assist in identification as supplementary evidence. - However, they can be **altered, fade over time, or may not be sufficiently unique** to reliably identify an individual on their own. - They lack the **consistency, permanence, and distinctiveness** of fingerprints for definitive forensic identification.
Question 8: Which of the following is used for sex chromatin testing?
- A. Testosterone receptors
- B. Phenotypic features
- C. Hormone levels
- D. Barr body (Correct Answer)
Explanation: ***Barr body*** - The **Barr body**, or sex chromatin, is an inactivated X chromosome found in the somatic cells of females. - Its presence or absence is used in sex chromatin testing to determine the number of X chromosomes. *Testosterone receptors* - **Testosterone receptors** are involved in mediating the effects of androgens and are not directly used for sex chromatin testing. - Abnormalities in these receptors can lead to conditions like **androgen insensitivity syndrome**, but they don't assess X chromosome number. *Phenotypic features* - While **phenotypic features** (visible characteristics) can suggest a person's sex or potential chromosomal abnormalities, they do not directly provide information about sex chromatin. - Definitive diagnosis requires **cytogenetic** or genetic testing. *Hormone levels* - **Hormone levels** (e.g., testosterone, estrogen) can indicate endocrine function but are not used to directly assess sex chromatin. - They reflect the activity of the gonads rather than the presence of inactivated X chromosomes.
Question 9: Best method to evaluate bone defect is
- A. Use of Florida probe
- B. Sounding (Correct Answer)
- C. Bitewing radiograph
- D. IOPA
Explanation: ***Sounding*** - **Sounding** involves inserting a periodontal probe into the bone defect to measure its depth and morphology, providing a direct and accurate assessment. - This method is particularly useful for evaluating the **clinical attachment loss** and the configuration of intrabony defects. *Use of Florida probe* - The **Florida probe** is a computerized periodontal probe used for precise measurement of probing depths and clinical attachment levels. - While accurate for soft tissue measurements, it does not directly assess bone defects or their morphology. *Bitewing radiograph* - **Bitewing radiographs** are primarily used to detect interproximal caries and assess the alveolar bone level. - They provide a two-dimensional image and are not ideal for evaluating the three-dimensional morphology or true depth of bone defects. *IOPA* - **Intraoral periapical (IOPA) radiographs** show the entire tooth, including the apex and surrounding bone. - While they can reveal some bony changes, they offer a two-dimensional view and may underestimate the extent of bone loss, especially around the roots, due to superimposition.
Question 10: Preauricular sulcus is useful for determination of:
- A. Sex (Correct Answer)
- B. Stature
- C. Age
- D. Race
Explanation: ***Sex*** - The **preauricular sulcus**, also known as the sulcus preauricularis, is a groove found on the ilium near the sacroiliac joint. - This feature is generally more pronounced and frequently present in **females**, particularly those who have given birth, making it a useful indicator for **sex determination** in skeletal remains. *Stature* - **Stature estimation** typically involves measuring the lengths of long bones (e.g., femur, tibia, humerus) and applying population-specific regression formulas. - The preauricular sulcus is a morphological feature of the pelvic bone and does not directly correlate with an individual's overall height. *Age* - **Age estimation** in adults often relies on degenerative changes in joints, sternal rib ends, pubic symphysis morphology, or dental wear. - While the presence of a preauricular sulcus is more common in females and can be associated with childbearing, it is not a primary or reliable indicator for estimating an individual's chronological age. *Race* - **Racial (ancestral) determination** in forensic anthropology is primarily based on craniofacial features, such as nasal aperture shape, orbital morphology, and facial prognathism. - The preauricular sulcus is not recognized as a distinguishing characteristic for differentiating between various ancestral groups.
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