A randomized controlled clinical trial was conducted in the Oral Surgery Unit, Faculty of Medicine and Dentistry, University of Valencia. The research was carried out following the principles described in the Helsinki Declaration and the study was approved by the Institutional Review Board of the Ethics Committee of the University of Valencia (1937615).

Fifty patients were included in the study according to the selection criteria.The osteotomies were randomized in two groups: the control group was performed under the high-speed drilling (800 rpm) with irrigation technique and the study group under the low-speed drilling without irrigation technique (50 rpm). The randomization tool was www.randomization.com.

Before the intervention, a preoperative orthopantomography and CBCT (Cone Beam Computerized Tomography) were taken for all the patients. Every patient was submitted a prophylactic hygiene 7 days before the intervention and 2 g of oral amoxicillin tablet 1 hour before the intervention (Clamoxyl®, GlaxoSmithKline, Madrid, Spain) was prescribed as a prophylaxis medication.

All the surgeries were performed by the same experienced operator (JCBM). The interventions were conducted under local anesthesia (4% articaine with 1: 100,000 adrenaline (Inibsa®, Lliça de Vall, Barcelona, Spain). The IPX® implant model (Nueva Galimplant S.L, Sarria, Galicia, Spain) was placed in the present study.

Surgical drills with stop (K Fres Stop ®, Nueva Galimplant S.L, Sarria, Spain) were used to prepare the osteotomies. The drilling sequence used will be: initial lance drill, followed by conical drills of 2.0 mm, 2.6 mm, 3.2 mm and 3.6 mm. The implants were apico-coronally situated at 4 mm to the mucosal margin with a torque of 35 Ncm.

The placed implants were IPX Model (Nueva Galimplant S.L., Sarria, Spain) with a 2-mm height anti-rotational abutment of one piece (Nueva Galimplant S.L, Sarria, Spain). The healing was non-submerged.

As postoperative medication 1 g of paracetamol (Bexistar®, Bacino Laboratory, Barcelona, Spain) on demand maximum every 8 hours were prescribed. Postoperative hygiene and oral care instructions were explained to the patient. A mouthwash of 0.12% chlorhexidine (GUM®, John O. Butler / Sunstar, Chicago, IL, USA) twice daily for two weeks was recommended too. The sutures were removed 7 days after surgery. Prosthetic loading will be performed 10 weeks after implant placement.

Inclusion Criteria:

• healthy adults, plaque and bleeding index less than 25%, sufficient bone height and width for implant placement, vestibular keratinized gingiva of at least 2 mm and stable occlusion and healthy periodontium.

Exclusion Criteria:

• any edentulous area requiring bone grafting procedures, medical conditions that contraindicate implant surgery such as severe bruxism or poor hygiene, pregnant or lactating patients, bisphosphonate therapy, patients receiving chemotherapy and radiotherapy to the head and neck, patients non-collaborators, incomplete data collection or lack of control assistance.