P - Population/Patient Problem Adult patients requiring full coverage porcelain-fused-to-metal (PFM) crown restorations I - Intervention PFM crowns veneered with porcelain system cemented using self-adhesive resin cement in DUAL-CURED mode (light-cured for 20 seconds per surface) C - Comparison PFM crowns veneered with porcelain system cemented using self-adhesive resin cement in SELF-CURED mode (no light curing, 5 minutes self-cure) O - Outcome(s)

• Primary: Retention of PFM crowns (Modified USPHS criteria)
• Secondary: Marginal adaptation, recurrent caries, marginal discoloration (Modified USPHS criteria) T - Time 18-month follow-up period with evaluations at baseline, 6, 12, and 18 months

Inclusion Criteria:

1. Adult patients requiring full coverage PFM crown restorations
2. Age ≥ 21 years
3. Vital or endodontically treated teeth
4. Sufficient tooth structure for crown retention
5. Willing and able to provide written informed consent
6. Ability to attend all follow-up appointments
7. Adequate oral hygiene as determined by the investigator

Exclusion Criteria:

1. Patients with active periodontal disease (probing depth > 4mm, bleeding on probing)
2. Patients with severe parafunctional habits (e.g., bruxism confirmed by clinical examination)
3. Poor oral hygiene (plaque index > 30%)
4. Pregnancy or nursing
5. Systemic diseases affecting treatment outcomes (e.g., uncontrolled diabetes, immunosuppression)
6. Known allergies to study materials (metal alloys, porcelain, or resin cement components)
7. Inability to comply with study requirements
8. Current participation in other dental clinical trials
9. Active orthodontic treatment