The primary mechanism by which severe mandibular incisor crowding is hypothesized to independently increase the risk of localized periodontal breakdown, beyond confounding factors like poor hygiene, is:

The primary mechanism by which severe mandibular incisor crowding is hypothesized to independently increase the risk of localized periodontal breakdown, beyond confounding factors like poor hygiene, is:

A. Increased horizontal force application on the periodontium

B. Increased localized tooth mobility secondary to reduced bone support

C. Reduced access for optimal plaque control by the patient

D. Development of fenestrations and dehiscences due to tooth displacement

The correct answer is D. Development of fenestrations and dehiscences due to tooth displacement

Severe mandibular incisor crowding causes teeth to displace or rotate within the alveolar housing, violating bone constraints and leading to cortical plate resorption. This results in fenestrations (narrow bone defects exposing root surfaces) and dehiscences (wider marginal defects causing gingival recession and reduced bone support), increasing localized periodontal breakdown risk independently of plaque accumulation or hygiene. Studies, including a 2024 review in the British Dental Journal, highlight that crowded, labially displaced incisors often lack adequate labial gingival coverage, while lingual positioning creates excess tissue and undermined support, predisposing to attachment loss. Proclined incisors in crowded arches show up to a 50% chance of 2 mm bone loss per 8° of proclination, per CBCT analyses. This mechanism differs from hygiene-related plaque retention (option C) or secondary effects like mobility (option B), and while horizontal forces (option A) may contribute, displacement-induced defects are the primary hypothesized pathway in orthodontic literature.

Primary determinant for a clinically significant increase in the risk of maxillary incisor trauma in the mixed dentition

Which of the following overjet thresholds has been most consistently supported by systematic reviews as the primary determinant for a clinically significant increase in the risk of maxillary incisor trauma in the mixed dentition?

A. Overjet greater or equal to 1.5 mm 

B. Overjet greater or equal to 6 mm 

C. Overjet greater or equal to 3 mm

D. Overjet greater or equal to 4.5 mm

The correct answer is: C. Overjet greater or equal to 3 mm

Systematic reviews, including Nguyen et al. (1999) in the European Journal of Orthodontics, show that an overjet ≥3 mm approximately doubles the risk of maxillary incisor trauma in children, including mixed dentition, based on a meta-analysis of 11 studies (pooled OR ≈2.0). This threshold is consistently cited as the point where risk significantly increases, with ORs ranging from 1.94 to 5.19 in mixed dentition per Arraj et al. (2019) in Dental Traumatology (41 studies). Later reviews, like Pandis et al. (2022) in the British Dental Journal, reinforce >3 mm as a key early indicator for trauma risk in mixed/permanent dentitions (7–14 years).

Higher thresholds like ≥6 mm show stronger associations (OR 3.85) but only in permanent dentition, not consistently in mixed. ≥4.5 mm and ≥1.5 mm lack support in reviews for this stage. Thus, ≥3 mm is the most consistently backed primary determinant.

16th International Orthodontic Conference of ODOAN, Dharan, Nepal

CLICK HERE FOR REGISTRATION TO MAIN CONFERENCE

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Calling all orthodontists, residents, and dental pros! The 16th International Orthodontic Conference of ODOAN is landing in Dharan, Nepal on Nov 15, 2025 – your ultimate hub for cutting-edge insights, networking, and innovation in orthodontics! 🌟

Don't miss the exclusive Pre-Conference Workshops on Nov 14:

Workshop 1: In-Office Aligners with Dr. Abhishek Gupta (Master digital smiles!)

Workshop 2: Self-Ligation & TADs for Complex Malocclusions with Dr. Abhishek Ghosh (Tackle tough cases like a pro!)

Early Bird rates extended till Oct 15 – register NOW and save big! PG residents: As low as NPR 7500 for main + NPR 2000 for both workshops. International? Just $90-100 USD entry! After October 15, $120 only.

Join 100s of global experts, ignite your practice, and explore Nepal's vibes. Spots filling fast – secure yours today!

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The spontaneous production of an electric current resulting from two dissimilar metals in the oral cavity is called:

The spontaneous production of an electric current resulting from two dissimilar metals in the oral cavity is called:

A. Nuclear reaction

B. Galvanic action

C. Precipitation reaction

D. Thermodynamics

The correct answer is B. Galvanic action

Galvanic action, also known as oral galvanism, occurs when two dissimilar metals in the oral cavity contact saliva (an electrolyte), forming a battery-like setup that generates a spontaneous electric current. This can cause symptoms like metallic taste, pain, or tissue irritation. Studies and dental resources confirm this electrochemical process is specific to bimetallic interactions in the mouth, distinguishing it from unrelated options: nuclear reactions (subatomic), precipitation (ion formation), and thermodynamics (energy principles).