Evaluation of the primary stability in patients with different techniques for placement of subantral implants: conventional drilling, underpreparation and use of motorized expanders.

INTERVENTION: Placement of subantral implants using different techniques: ‐ Under preparation: under‐drilling or preparation with drills with a diameter smaller than the diameter of the implant. ‐ Use of motorized bone expanders: the expanders are inserted into the bone with motor‐driven rotation, which decreases surgical trauma and provides more control over the expansion site. The thread pattern compacts the bone laterally as the instrument is advanced toward the bone crest. ‐ Under preparation: once only 1‐2 hours session. ‐ Use of motorized bone expanders: once only 1‐2 hours session. At 12 weeks in the second surgical phase, the ISQ will be measured in all patients. This intervention will be carried out by professors of Oral Surgery in the operating room of official master of oral surgery and implantology at the University of Granada. CONDITION: Oral and Gastrointestinal ‐ Other diseases of the mouth, teeth, oesophagus, digestive system including liver and colon Single edentulism or partial edentulism in posterior maxilla; ; Single edentulism or partial edentulism in posterior maxilla Surgery ‐ Surgical techniques PRIMARY OUTCOME: Implant stability quotient (ISQ): to measure primary stability.[‐ On the day of surgery: ISQ is measured when implants are placed.; ‐ 12 weeks after surgery: ISQ is measured again.; The Osstell ISQ module from W&H, which is available as an accessory, enables a safe assessment of implant stability. The Implant Stability Quotient (ISQ) has been tested in numerous clinical studies.; ; ] Insertion torque: it is measured with the motor that places the implant.; ; The Insertion torque promotes a rotation in the implant on which the force is applied, being expressed in Ncm units.; [The insertion torque is measured on the day of surgical intervention when implants are placed.; ; ; ; ] SECONDARY OUTCOME: Early failure of the implant ; ; It is measured when the implant presents clinical and radiological symptoms[Insertion torque can only be measured at the time the implants have been placed. ; Our secondary outcome variable insertion torque does influence early implant failure. Thus, a very low insertion torque can be associated with early implant failure. ; ] INCLUSION CRITERIA: ‐Patients who present single or partial edentulism at the level of the upper premolars and molars and who wish to have implants placed ‐Subjects over 18 years of age ‐ Patients who do not abuse alcohol, drugs or chronic smokers (< 10 cigarettes a day) ‐ Patients with an adequate periodontal status and if they suffer from previously treated periodontal disease ‐ Patients with no known mental disorders, with an adequate level of education to understand the study and who sign their informed consent to participate in it.