The observed medical device in this study were SGS P7D Dental implant. The device replaces the lost tooth root, and provides support for the dental bridges and crowns, or overdenture replacements. This medical device provides the opportunity to to replace partial or complete missing teeth. Device material: Ti-6Al-4V Device surface protection: Corundum Blasting and

1. phosphate surface treatment or
2. hydroxylapatite surface treatment

A prospective, randomized, two-arms "split-mouth" study. The two arms: right and left of the same mandible of the same volunteer with a different surface treatment, but every other circumstances of the implants are the same, the same device with different surface materilas.

"A" treatment: Implant with phosphate surface treatment is the lower one in the right side of the jawbone, with hydroxylapatite surface treatment implant is placed in the left side of the lower jaw. "B" treatment: Implant with phosphate surface treatment in the lower jaw on the left side, the bottom is an implant with hydroxylapatite surface treatment is inserted into the right side of the jaw bone

Inclusion Criteria:

• complete lack of teeth in the lower jaw
• decision of the investigator: the patient is appropriate for implantation, clinical conditions are sufficient (adequate soft tissue and bone conditions and occlusal position;)
• the patient's consciousness is clear, understand the planned intervention.
• the patient communicates well with the examiner and is able to understand and comply with the requirements of the test plan.
• witten informed consent

Exclusion Criteria:

• Pregnant or lactating women
• Women of childbearing potential, unless she uses effective birth control until the completion of the final radiological examination, and for another 4 weeks after that.
• A disease (including, but not limited to metabolic, hematological, kidney, liver, lung, neurological, endocrine, cardiac, infectious and gastrointestinal disease), which -in the opinion of the investigator- significantly affects the health of the examined person and/or exposes to an unacceptably high risk the person receiving the implantation treatment.
• Malignant disease in the medical history in the preceding 24 months.
• Known HIV, hepatitis B or hepatitis C, or any other considered viral infection relevant by the examiner known at the tome of randomization
• A medical or psychiatric illness which, in the opinion of the investigator, excludes that the participant adheres to the protocol, or complete the study according to the protocol.
• Participation in an other interventional clinical study within 6 months prior to treatment.
• Known allergy to the implant or to the invetigational template or any of its components.
• Limitation of mouth opening, which make unpossible to complete the procedure, based on the opinion of the investigator
• Increased pharyngeal reflex, reduced ability to tolerate intraoral manipulation
• Radiotherapy, previous irradiation of the jawbones
• INR > 2.5
• Immunosuppressed patient
• previous or current bisphosphonate treatment
• Known alcohol or drug abuse
• Heavy smoking (≥ 20 cigarettes per day, or another form of smoking, used in an equivalent amount)
• Untreated periodontitis
• Local infection of the implant in the planned area
• Lack of dental hygiene, e.g. not removed radixes, plaque and calculus, or radiologically detectable potential periapical focus (also in asymptomatic case )
• Insufficient or poor oral hygiene
• Transient infectious state, with or without fever