This study will compare clinical and radio graphic outcomes of two minimally invasive different treatment modalities for atrophied unilateral distal extension maxillary ridges these modalities include

1. Medially placed implant and Implant retained distal extension removable partial denture
2. Sinus lift and long implant to support fixed screw-retained prosthesis

Patient selection:

For this study, 40 patients were selected from the clinic of Prosthodontics Department, Faculty of Dentistry, Mansoura University.

Inclusion criteria:

The patients will be selected according to the following:

• They have atrophied unilateral distal extension maxillary ridge and remaining alveolar bone height 6- 8 mm as verified by preoperative cone beam. They are healthy, free from any systemic diseases relating to the bone resorption (diabetes - hyperparathyroidism). This can be achieved through medical history and clinical examination by a physician and laboratory investigations.
• Posterior maxillary alveolar ridge deficient in height, width and covered with healthy firm covering.
• Patients are less satisfied with conventional removable partial denture.
• Absence of maxillary sinus diseases. Exclusion criteria

Patients were not eligible for this work if any of the following criteria were met:

• Acute or chronic sinus pathology
• History of a sinus augmentation in the past in the relevant sinus
• Poor dental hygiene. Smoker.
• Compromised general health (uncontrolled diabetes, bleeding disorder….). All patient were informed about all procedures that will be done and they sign the written consent form of ethical committee in faculty of dentistry Mansoura university.

Three treatment groups will be classified randomly, as follow:

• Group I: patients received one implant in premolar area medial to maxillary sinus and used to retain partial over-denture.
• Group II: patient underwent sinus lift and receive screw retained prosthesis on long implant All implants were inserted using computer guided and flap-less implant surgery and conventional loading protocol was used.

Evaluation methods Clinical and radio-graphic evaluation

1. Modified Plaque index. Assessment of plaque accumulation with a modified plaque index : Score 0: No detection of plaque, Score 1: Plaque only recognized by running a probe across the smooth marginal surface of the implant, Score 2 Plaque can be seen by a naked eye, Score 3 Abundance of soft matter.
2. Marginal index. Assessment of bleeding tendency with a modified bleeding index : Score 0 No bleeding when a periodontal probe is passed along the margin adjacent to the implant. Score 1 Isolated bleeding spot visible, Score 2 Blood forms a confluent red line on margin, Score 3 Heavy or profuse bleeding.
3. Attachment level. Distance from the junction implant/crown to the most apically probe able portion, in millimeters.
4. Pocket depth. Distance between the margin and the most apically probable portion, in millimeters Assessed by insertion of a standard periodontal probe with a point diameter of 0.5 mm using a probing force of 0.5 N.
5. Implant stability quotient. Using resonance frequency analysis b- Radio-graphic evaluation will be performed in terms of:

Vertical bone loss will be evaluated as follows:

The distance between implant plate form and first bone to implant contact will be evaluated after one year.

Inclusion Criteria:

• The patients will be selected according to the following:

  • They have atrophied unilateral distal extension maxillary ridge and remaining alveolar bone height 6- 8mm as verified by preoperative CBCT, They are healthy, free from any systemic diseases relating to the bone resorption (diabetes - hyperparathyroidism). This can be achieved through medical history and clinical examination by a physician and laboratory investigations.
  • Posterior maxillary alveolar ridge deficient in height, width and covered with healthy firm mucosa.
  • Patients are less satisfied with conventional RPD.
  • Absence of maxillary sinus diseases.

Exclusion Criteria:

• • Acute or chronic sinus pathology

  • History of a sinus augmentation in the past in the relevant sinus
  • Poor dental hygiene. Smoker.
  • Compromised general health (uncontrolled diabetes, bleeding disorder