Evaluation of the Aesthetic Outcome of Lithium Disilicate (e.Max) All Ceramic Crowns on Titanium Implant Abutments in the Aesthetic Zone After Different Color Masking Approaches

Evaluation of the Esthetic Outcome of Lithium Disilicate (e.Max) All Ceramic Crowns on Titanium Implant Abutments in the Esthetic Zone After Different Color Masking Approaches; a Randomized Clinical Trial

Implants have become the perfect solution for replacement of missing single teeth, partial or even complete edentulism.18 However, the dilemma of anterior implant-supported prosthesis is still not quite solved.19-21 Implant abutments are one of the esthetic influencers. And concerning the material, ready-made titanium abutments are considered the gold standard of all. Nevertheless, the esthetic properties remain doubtful. Lithium disilicate ceramics have been used as implant superstructures for many years now for their combined esthetic and biomechanical properties. The purpose of the present study is to evaluate the effect of using titanium implant abutment on the color of lithium disilicate crowns and the significance of masking the titanium abutments with opaque porcelain or using opaque lithium disilicate coping on the final esthetic outcome

Clinical resemblance is one the of main factors that preclude the success of any restoration. The use of conventional titanium implant abutment and ceramic restoration succeeded to prevail until now. New ceramic and polymer derivatives have been introduced such as hybrid ceramics, PEEK and PEKK. However, the low mechanical properties and the ease of breakage still limited them to certain clinical situations. Hybrid fixture-abutment combinations such as hybrid abutments and hybrid crowns proved to be highly efficient in the literature. But the technique sensitivity and the urge of high clinical and laboratory skills are obstacles that must be taken into consideration. This is the reason that finding esthetic modification of the conventional techniques seems reasonable. Masking the color of the underlying abutment appears to be a simple and easily achievable solution for having a highly esthetic implant supported prosthesis.

The importance of peri-implant soft tissues, whether esthetically or biologically, has been emphasized in literature. (4) Furthermore, achieving the desired esthetic outcome depends on simultaneously matching the proper esthetic criteria of the tooth and its supporting structures. (5) Esthetic failures in implant dentistry can be categorized as pink-tissue failures and white-tissue failures. (6) Pink esthetics include color, texture and level of peri-implant tissues (7), while white esthetics include color, shape and characterization of crown. (3) The mode of fabrication also influences the performance of the materials, where the use of press technology facilitates the construction of implant supported crowns, offering precision of fit, durability and esthetic materials application. (11)

Inclusion Criteria:

• 1. Above 18 years old 2. Literate, capable of reading and signing the informed consent document 3. Healthy, Free from or with controlled systemic disease 4. With acceptable oral health to support implant restorations 5. With good bone quality and quantity 6. Cooperative, accepting follow up and maintenance sessions 7. Having missing tooth in esthetic zone

Exclusion Criteria:

• 1. Under 18 years old 2. Illiterate, unable of comprehending or signing the informed consent document 3. Unhealthy with uncontrolled systemic disease (e.g. Diabetes or hypertension) 4. Pregnancy 5. With unfavorable oral state that might affect implant procedure and restoration 6. Uncooperative, not willing to return for follow up visits