The present study was compared the level of alveolar bone loss, clinical parameters and IL-1β in PICF in one- or two-stage surgical procedures. Half of the patients were performed tissue level implant while other half were performed bone level implant.

The present study included 40 healthy patients (24 males and 16 females; mean age, 30.75 ± 8.58 years) who had one tooth absent in the mandible, at the Department of Periodontology, Dicle University, Diyarbakir, Turkey, between 2010 and 2011. All patients were informed in detail about the study protocol, and they were asked to sign informed consent forms. Ethics committee approval was obtained from Dicle University Ethics Committee for this study (D.Ü.D.F.E.K.2010/02)

This study was designed as a prospective, randomized, controlled study. Randomization was performed prior to surgery by opening a sequentially numbered sealed envelope corresponding to the patient recruitment number. Investigators received randomization instructions only after enrolling a subject and immediately prior to surgery. The participants were randomly divided into two groups. A one-stage surgical procedure was performed on 20 patients (Group I) and a two-stage surgical procedure was performed on the other 20 patients (Group II). The primary outcome of the study was a change in alveolar bone level at the implant site between T0 and T2 months after surgery measured on CBCT. The secondary outcomes between T0, T1, and T2 were changes the level of IL-1β PICF, probing pocket depth (PPD), modified plaque index (mPI), modified gingival index (mGI), and modified bleeding index (mBI). All implants (Straumann AG, Waldenburg, Switzerland) were inserted by the same periodontist (T.T.Y.) in the present study. Pre-surgical radiographic evaluation was conducted using CBCT. Before surgery, the patient's mouth was rinsed with chlorhexidine mouthwash. After local anesthesia, full thickness flaps were reflected, and osteotomies were prepared in the first mandibular molar sites. In these surgical operations, 20 tissue-level and 20 bone-level dental implants 12 mm in length and 4.8 mm in diameter were inserted in Group I and Group II, respectively. Three months later, second-stage surgery was performed and implant exposed into the oral cavity. Cover screw was removed and replaced with healing abutments. Three months waited for second surgery in bone level implants. Patients of both groups were enrolled in a monthly periodontal/peri-implant maintenance program after abutments were connected in which, full mouth scaling was performed around all natural teeth and implant surfaces. Oral hygiene instructions regarding regular tooth brushing were given and patients were encouraged to floss the teeth and periimplant surfaces daily. There was no implant failed during the study and adverse event of these treatments.

Inclusion Criteria:

• patients in the study who had one tooth absent in the mandible
• patients in the study should be least 18 years old.

Exclusion Criteria:

Patients in the study were the absence of the following points;

• poor mouth hygiene,
• bruxism, dental implants,
• chemotherapy or radiotherapy,
• addictions (alcohol, cigarettes, and medications),
• disease in the jawbones observed clinically or radiographically,
• pregnancy,
• antibiotic and/or anti-inflammatory medication use in the last three months.

Individual participant data can not be used another purpose such as meta-analyses, reanalysis, or replication of results.

Only the surgeon knows detail about the groups of participants. Participant, care provider,outcomes assessor have no knowledge of groups