The objective of this randomized controlled trial is to evaluate changes in marginal bone levels and soft tissue dimensions around implants placed with the IAI at different positions in relation to the alveolar crest

The objective of this randomized controlled trial is to evaluate changes in marginal bone levels and soft tissue dimensions around implants placed with the IAI at different positions in relation to the alveolar crest. Subjects will be included with the absence of 2-4 teeth in the posterior region of the maxilla or mandibular. Twenty patients will be recruited. Two implant placement depths, equicrestal and subcrestal, were randomly assigned to two sites of each patient with a predefined randomization tables (one crestal implant and one subcrestal implant). Patients will be recalled for oral hygiene maintenance and prosthetic controls at 1year, 3 years, 5 years after final restoration.

Inclusion Criteria:

1. Absence of 2-4 teeth in the posterior region of the maxilla or mandibular;
2. Bone volume sufficient for implants with 4.1-mm size and 8- to 12-mm height and with no need for hard or soft tissue augmentation for implant treatment;
3. Periodontally healthy.

Exclusion Criteria:

1. Systemic diseases that may affect bone and soft tissue healing, such as diabetes, osteoporosis, Paget's disease, and patients with cancer;
2. Uncontrolled periodontal disease or poor oral health with neither good nor adequate plaque control;
3. Parafunctional habits, such as the grinding or clenching of teeth;
4. Smoking habit (more than 10 cigarettes per day);
5. Pregnancy and breastfeeding.