The microthreaded and platform switched implants could control the stress in the suitable range. The splint would disturb the function. So it is necessary to know whether the splinted single-unit crowns is fit for the adjacent multi-implants.

Outcome variables: Splinted single-unit crowns on one side implants and non-splinted single-unit crowns on the other side Materials and method: 80-100 consecutive implants in at least 20 patients would be included for implant- supported restorations in the posterior maxilla or mandibular. All patients would be in general good health. For every patient, the same posterior teeth had lost on both sides for more than 6 months. All patients were treated by the same qualified surgeon.

Prosthetics procedure would be performed by an experienced prosthodontist. The two sides were allocated to the test or the control group according to the predefined computer-generated randomization table. Clinical evaluations and radiographic analysis were performed by an oral and maxillofacial radiologist who was not aware of the type of Prosthetics technique that was used.

The microthreaded and platform switched implants could control the stress in the suitable range. The splint would disturb the function. So it is necessary to know whether the splinted single-unit crowns is fit for the adjacent multi-implants.

Outcome variables: Splinted single-unit crowns on one side implants and non-splinted single-unit crowns on the other side Materials and method: 80-100 consecutive implants in at least 20 patients would be included for implant- supported restorations in the posterior maxilla or mandibular. All patients would be in general good health. For every patient, the same posterior teeth had lost on both sides for more than 6 months. All patients were treated by the same qualified surgeon.

Prosthetics procedure would be performed by an experienced prosthodontist. The two sides were allocated to the test or the control group according to the predefined computer-generated randomization table. Clinical evaluations and radiographic analysis were performed by an oral and maxillofacial radiologist who was not aware of the type of Prosthetics technique that was used.

Inclusion Criteria:

1. All patients would be in general good health.
2. All patients would need for fixed implant-supported prosthesis in the double posterior maxillae or mandibulae (there were at least two corresponding adjacent teeth lost in both sides from the 1st premolar to 2nd molar).
3. The patients could be followed-up for 36 months after prosthetic loading
4. A wide ridge of bone allowing the insertion of a 4mm platform implant and at least 8mm of bone in vertical height would be required.
5. The same posterior teeth had lost on both sides for more than 6 months.

Exclusion Criteria:

1. For implant site, a ridge of bone do not allow the insertion of a 4mm platform implant and at least 8mm of bone in vertical height.
2. Current need for pre-surgical bone or soft tissue augmentation in the planned implant area;
3. Uncontrolled pathologic processes in the oral cavity;
4. History of radiation therapy in the head and neck region;
5. History of chemotherapy within 5 years prior to surgery;
6. Systemic or local disease or condition that could compromise post-operative healing and/or osseointegration;
7. Uncontrolled diabetes mellitus;
8. Corticosteroids or any other medication that could influence post-operative healing and/or osseointegration;
9. Smoking more than 10 cigarettes/day;
10. Present alcohol and/or drug abuse