MJDF Part 1 - Membership of Joint Dental Faculties Orthodontic Assessment and Referral Questions and Answers — Questions and Answers
Question 1: An 8-year-old child presents with a unilateral posterior crossbite affecting the maxillary right first permanent molar. On closure, you observe a clear mandibular displacement to the right into maximum intercuspation. According to UK guidelines, what is the most appropriate management plan?
- Review the patient in 12 months to see if the crossbite self-corrects.
- Refer for an orthodontic opinion regarding early interceptive treatment. (Correct answer)
- Advise the patient to perform exercises to strengthen the contralateral masticatory muscles.
- Extract the opposing primary molar to eliminate the occlusal interference.
Correct answer: Refer for an orthodontic opinion regarding early interceptive treatment.
A unilateral posterior crossbite associated with a mandibular displacement is a strong indication for early orthodontic referral. Interceptive treatment, often with a maxillary expansion appliance, is typically recommended to correct the transverse discrepancy and eliminate the functional shift, which may help prevent asymmetrical jaw growth.
Question 2: A 10-year-old patient attends for a routine examination. You are unable to palpate the maxillary permanent canines in the buccal sulcus, and you note that the maxillary lateral incisors appear slightly proclined. What is the most appropriate immediate action?
- Take a periapical radiograph of the primary canines.
- Advise the patient that this is a normal stage of development and review in one year.
- Refer the patient for an orthodontic opinion and further radiographic investigation. (Correct answer)
- Extract the primary canines to encourage eruption of the permanent successors.
Correct answer: Refer the patient for an orthodontic opinion and further radiographic investigation.
By the age of 10, maxillary permanent canines should be palpable in the buccal sulcus. Their absence, especially when combined with other signs like proclined lateral incisors, is a key indicator of a potential impaction or ectopic eruption. An early referral to an orthodontist for assessment, which usually includes radiographic investigation like a panoramic radiograph (DPT/OPG), is crucial for timely diagnosis and management.
Question 3: When using the Index of Orthodontic Treatment Need (IOTN) for NHS funding eligibility, the Aesthetic Component (AC) is used as a qualifier for patients with a Dental Health Component (DHC) of 3. Which AC score range indicates a sufficient aesthetic need to qualify for treatment?
- AC score of 1-4
- AC score of 8-10
- AC score of 6 or greater (Correct answer)
- AC score of 5 or greater
Correct answer: AC score of 6 or greater
For a patient to qualify for NHS orthodontic treatment with a DHC grade of 3 (borderline need), their case must also demonstrate a significant aesthetic need. In the UK, this is defined as having an Aesthetic Component (AC) score of 6 or greater.
Question 4: A 13-year-old patient presents with congenitally absent maxillary lateral incisors (hypodontia). The primary lateral incisors are still in place. According to the IOTN Dental Health Component (DHC), which grade would this patient most likely be assigned, assuming orthodontic treatment is required?
- 3h
- 5i
- 2h
- 4h (Correct answer)
Correct answer: 4h
The IOTN DHC has specific categories for hypodontia. Grade 4h is for 'Less extensive hypodontia requiring pre-restorative orthodontics or orthodontic space closure to obviate the need for a prosthesis'. The congenital absence of two teeth falls into this category, as managing the space orthodontically is a key part of the treatment plan.
Question 5: Which of the following clinical features is most characteristic of a true Skeletal Class III malocclusion?
- A convex facial profile with a recessive chin.
- A reverse overjet that eliminates upon guiding the mandible into centric relation.
- A concave facial profile and a Class III incisor relationship. (Correct answer)
- Competent lips at rest and a Class I molar relationship.
Correct answer: A concave facial profile and a Class III incisor relationship.
A true Skeletal Class III malocclusion is defined by a skeletal discrepancy where the mandible is positioned anteriorly relative to the maxilla. This typically manifests clinically with a concave facial profile and a Class III incisor relationship (underbite). A reverse overjet that corrects in centric relation suggests a pseudo-Class III or functional shift, not a true skeletal issue.
Question 6: A 12-year-old patient has a reverse overjet of 2.5mm. The patient and parent report difficulties with speech and mastication related to the anterior crossbite. According to the IOTN Dental Health Component (DHC), what is the correct grade?
- 3b
- 4m (Correct answer)
- 5m
- 4b
Correct answer: 4m
The IOTN DHC Grade 4m is defined as 'Reverse overjet greater than 1mm but less than or equal to 3.5mm with recorded masticatory and speech difficulties'. Since the patient's reverse overjet is 2.5mm and there are reported functional issues, this is the most appropriate classification.
MJDF Part 1 - Membership of Joint Dental Faculties Orthodontic Assessment and Referral Questions and Answers
An 8-year-old child presents with a unilateral posterior crossbite affecting the maxillary right first permanent molar.
On closure, you observe a clear mandibular displacement to the right into maximum intercuspation.
According to UK guidelines, what is the most appropriate management plan?