implant will be inserted in patients with kennedy class 3 or 4 partially edentulous mandible .the implants will be inserted using teeth supported surgical guide fabricated from two different materials

Inclusion Criteria:

1. Patients with skeletal Angle´s class I maxilla-mandibular relationship,
2. adequate inter-arch distance, have Kennedy class 3 or 4 partially edentulous mandible of more than 2 teeth missed and will be applied for the treatment of tooth loss and requiring fixed prosthodontic rehabilitation
3. normal Physical and psychological status to tolerate conventional implant procedures,
4. Their residual ridge had sufficient bone volume for implant installation and was covered by firm mucoperiosteum.

Exclusion Criteria:

1. Smokers.
2. Patients undergoing chemotherapy or radiotherapy and immunocompromised patients.
3. Patients with, systemic disease that might complicate post-operative healing or contribute to bone resorption, e.g uncontrolled diabetes, psychological disorders, or alcohol, tobacco, or drug abuse
4. parafunctional habits, poor oral hygiene, limited mouth opening, severe alveolar bone deficiencies,