Comparing between the failure rates of molar tubes bonded with conventional bonding technique using resin adhesive and the alternative bonding technique using compomer (containing glass ionomer) adhesive by adding a layer of compomer adhesive at the molar/tube interface.

Inclusion Criteria:

1. Patients requiring fixed appliance orthodontic treatment (with no previous orthodontic treatment).

2. Patients aged >12 years with full permanent dentition (excluding third molars).

3. Intact buccal enamel surface of the molars without any of the following:

   • Caries, abrasion, or any other crown defect (like hypoplasia).
   • Pretreatment chemical agents.
   • Restorations or fractures.
   • Morphological modifications or other crown alterations.

4. Patients who have the desire and ability to comply with the trial protocol.

Exclusion Criteria:

1. Treatments with planned extraction of first permanent molars.
2. Occlusal interference that prevents correct position of molar tube.
3. Patients with a craniofacial anomaly (like cleft lip and palate) and/or require orthognathic surgery.
4. Patients that require extra-oral or intra-oral anchorage device (headgear, palatal arch, lingual arch) or expander (quad-helix, hyrax).
5. Lack of consent to participate in the trial.