Based on current, high-level evidence, which occlusal feature has demonstrated the strongest, albeit weak, statistical association with an increased prevalence of pain-related Temporomandibular Disorders (TMD)?

 # Based on current, high-level evidence, which occlusal feature has demonstrated the strongest, albeit weak, statistical association with an increased prevalence of pain-related Temporomandibular Disorders (TMD)?

A. Anterior Open Bite

B. Class II Division 2 Malocclusion

C. Overjet greater or equal to 6 mm

D. Posterior Unilateral Crossbite

The correct answer is D. Posterior Unilateral Crossbite

High-level evidence from systematic reviews, such as the 2025 review by Alghamdi et al. in Frontiers in Neurology (analyzing 17 studies on children/adolescents), identifies posterior unilateral crossbite as having the strongest association with pain-related TMD signs/symptoms, including TMJ/muscle pain and tenderness. Pooled data show odds ratios (ORs) of 2.25–5.74 (95% CIs: 1.15–4.43 to 1.18–27.85; p<0.05 across studies like Pereira et al. 2009 and Perrotta et al. 2018), indicating a 2–6-fold increased risk, though with low GRADE certainty due to cross-sectional designs and heterogeneity. This exceeds associations for other features: anterior open bite (OR ~1.5–2.0 in select studies, e.g., Sonnesen 1998); Class II Division 2 (OR 2.61 for general Class II, but weaker/subgroup-specific for Div 2, per Šimunović et al. 2024); and overjet ≥6 mm (OR ~1.8–2.5, less consistent in mixed/permanent dentition per Manfredini et al. 2010). A 2025 meta-analysis by Chen et al. in BMC Oral Health reports 59% TMD prevalence in unilateral crossbite cases (95% CI: 46%–72%), vs. 40%–44% for others. Overall, while all links are weak (ORs <6, multifactorial etiology), crossbite shows the most consistent statistical signal.

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

CLICK HERE TO REGISTER FOR PRECONFERENCE WORKSHOPS 

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!

BANK DETAILS FOR PAYMENT OF REGISTRATION FEES

CLICK HERE FOR REGISTRATION TO MAIN CONFERENCE

CLICK HERE TO REGISTER FOR PRECONFERENCE WORKSHOPS

For queries: Dr. Samikshya Sangroula (9842031003) | Dr. Mona Pokharel (9841658338)

#ODOAN2025 #Orthodontics #DentalConference #NepalDentistry