Please select the eligibility criteria that correspond to the clinical trial below.
Title: Dental Arches Response to Haas-type RME Anchored to Deciduous vs Permanent Molars in Children With Unilateral Posterior Crossbite
Brief Summary: Posterior crossbite is a common clinical condition often associated with transverse maxillary deficiency and functional mandibular shift. This frequent malocclusion is not self-correcting and can lead to the development of craniofacial asymmetries and mandibular dysfunction.

The aim of the current study was to evaluate maxillary and mandibular arch widths' response to RME when it is anchored to the upper second deciduous molars or to the upper first permanent molars and to create a decision-making protocol for RME therapy in mixed-dentition patients.


Options:
A: Inclusion Criteria:

1. Patients indicated for fixed appliance orthodontic treatment who have a moderate crowding (3-6mm) according to the Little's irregularity index (LII).
2. Full set of lower permanent dentition excluding the third molars.
3. No history of trauma or root resorption in the lower incisors.

Exclusion Criteria:

1. Previous orthodontic treatment.
2. Less than 3mm of lower incisor crowding (LII) or with spaced incisors.
3. Severe crowding in the lower arch (greater than 7mm) which requires extraction.
4. Blocked-out teeth that cannot be engaged with the aligning archwire.
5. Patients with periodontally compromised teeth.
B: Inclusion Criteria:

* Subjects will be recruited from a sample of consecutive cases attending for routine fixed appliance orthodontic treatment with conventional pre-adjusted edgewise brackets that satisfy the following criteria: in the permanent dentition; a requirement for extraction of a premolar unit in each quadrant; incisor irregularity between 5-12 mm.

Exclusion Criteria:

* no medical contraindications; no craniofacial anomalies or cleft lip/palate;
C: Inclusion Criteria:

* Patients in mixed dentition
* Unilateral posterior crossbite at least of the first permanent molar
* Upper deciduous second molars available as RME anchoring teeth

Exclusion Criteria:

Primary exclusion criteria

* Previous orthodontic treatment
* Hypodontia in any quadrant excluding third molars
* Inadequate oral hygiene
* Temporomandibular joint disorders
* Craniofacial abnormalities
* Secondary exclusion criteria
* Lack of records
* Need for lingual arch
* Lack of consensus
* Need for other orthodontic treatment during rapid maxillary expansion
D: Inclusion Criteria:

1. Adult healthy patients , Male and female, Age range: 15-27 years.
2. Severe crowding ≤ 7 (Little's irregularity index)
3. Permanent occlusion.
4. Exist all the Mandibular teeth (except third molars).
5. Good oral and periodontal health:

   * Probing depth\<4 mm
   * No radiographic evidence of bone loss .
   * Gingival index≤ 1
   * Plaque index ≤ 1

Exclusion Criteria:

1. Medical problems that affect tooth movement (corticosteroid, NSAIDs, ...)
2. Patients have anti indication for oral surgery ( medical - social - psycho)
3. Presence of primary teeth in the mandibular arch
4. Missing permanent mandibular teeth (except third molars).
5. Poor oral hygiene or Current periodontal disease:

   * Probing depth ≥ 4 mm
   * radiographic evidence of bone loss
   * Gingival index \> 1
   * Plaque index \> 1
6. Patient had previous orthodontic treatment

Answer: C