الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
For this study, six healthy patients with a complete maxillofacial were selected. A full cast was made and delivered to all patients. A surgical stent was made using a conical CT scan and a 3D printer for each patient to guide the placement of the implants in the two canines of the mandible. After placing the two implants and waiting for the period of bone healing around them, the implants were loaded with the lower dentures by the spatial joint, according to the picking technique of the spatial joint retention caps and the color of the retention rings. The lower overdentures were divided into four groups as follows: group 1: Retention caps with a blue retention ring were captured in vitro indirectly. group 2: Retention caps with a pinkish-coloured retention ring were captured in the laboratory indirectly. group 3: Retention caps with a blue retention ring were taken directly into the patient’s mouth. group 4: Retention caps with a pink retention ring were taken directly into the patient’s mouth. After the retention was calibrated in the laboratory with the retention device, the measurement accuracy percentage was calculated in this study compared to the retention values of the manufacturer of the spatial connectors with an accuracy of up to 95%. The retention strength of each group of dentures was evaluated immediately after the lower denture was handed over to patients and after three and six months of denture use. 1- There was no statistically significant difference between the methods of capturing the spatial link retention caps after each measurement period. 2- Retention power decreased after six months of using dentures in all groups. Conclusion and recommendation: With the limited number of patients and the time period of this study, the following can be concluded: 1- Regardless of the color of the retention ring, there is no difference in the retention force of the lower dentures carried on two implants by the spatial link between the direct and indirect cap capture technique. 2- Using the indirect capture technique of spatial link retention caps to avoid clinical difficulties in the direct capture technique”