The purpose of this study is to investigate to what extent IOs improve the functionality of edentulous patients and changes in quality of life and overall patient satisfaction following treatment with IOs.

Edentulous individuals will be selected from patients attending the prosthodontic clinic. Then, new complete dentures will be provided; in a second stage half of these subjects (randomly selected) will receive IOs. The effect of different treatment protocols on chewing ability, patient satisfaction and OHRQoL will be investigated and assessed.

Inclusion Criteria:

1. Being edentulous in the upper and lower jaw for at least 1 year
2. Dissatisfied or cannot function with their complete lower denture
3. Age between 40 and 75
4. Suitable bone quality as assessed radiographically (CBCT) according to Zarb's classification。

Exclusion Criteria:

1. Physical and mental disabilities which interfere with the maintenance of implants;
2. Severe skeletal jaw discrepancies (class III)
3. Those who have already received or lost dental implants
4. Those who abuse drugs or alcohol
5. Smoking more than 10 cigarettes a day
6. Having received radiotherapy to the head and neck region for malignancies
7. Undergoing chemotherapy
8. On long-term therapy with steroids
9. immunosuppressants or biphosphonates
10. Insulin-dependent diabetic patients and uncontrolled onset diabetic patients
11. Those affected by chronic renal or liver disease
12. Systemic and local bone disorders and pathology
13. Serious cardiac and pulmonary disorders
14. Haemophilic disorders who are susceptible for increased bleeding and tendency for post-operative infections
15. Those who are at risk of developing bacterial endocarditis
16. Immune system compromised patients, including those with HIV

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