Comparative Evaluation Of the 3 Dimensional Implant Impression Accuracy Between Conventional and Digital Impression Using Two Different Intraoral Scanners:- An In Vivo Study

The study will be done to evaluate 3 dimensional implant impression accuracy between conventional and digital impression using two different intraoral scanners. The forthcoming in vivo study will be conducted in the department of Prosthodontics, Crown and Bridge , Maxillofacial Prosthodontics and Oral Implantology, I.T.S Dental College, Hospital and Research Centre, Greater Noida (U.P)   Patients of both genders aged from 18 years of age , who will be reporting to the department of Prosthodontics, Crown and Bridge , Maxillofacial Prosthodontics and Oral Implantology, I.T.S Dental College will serve as the source for the data collection.    A total of 10 patients with already placed implants will be the subjects for study.

**I.**Reference Model Fabrication

A Reference model will be made for each patient which will be serve as control for study. Reference model will be made by same procedure for each patient.   First, the healing abutments will be removed, and two square impression copings (4 mm diameter × 17 mm height;) will be hand tightened. The two impression copings will be splinted with autopolymerizing acrylic resin (Pattern Resin;).  To standardize the amount of splinting material for all instances, the dimension of the splinted assembly will be kept to 4 mm high and 2 mm wide; this amount of material could also prevent any distortion during the implant analog attaching procedure.   To verify the precise splinting procedure, the splinted assemblies will be sectioned through the middle of the index, and will be rejoined again with freshly mixed pattern resin material by the brush bead method. Then, the splinted assembly will be allowed to completely set prior to impression making. A periapical x-ray will be taken for every patient to confirm the complete seating before transferring it for impression making. After that, the splinted assembly will be removed, and analogs of the  same  size for all cases will be attached and hand tightened. They will then seated immediately in wet gypsum product.  To homogenize the impression making procedure, the gypsum powder and distilled water will used to produce each reference model.     After the stone will completely set, the splinted impression copings will be removed from the analogs. This fabricated model with the two analogs inside will be considered as the reference model (RM) in this study. For every participant, the RM will be first obtained with the same procedure as previously mentioned

**I.**Conventional implant impression technique and cast fabrication

**II.**Digital implant impression using two different intraoral scanners i.e. Aoralscan 3 (Shining 3D)   & CEREC Primescan (Dentsply sirona®).

Two scanners ( Primescan & Aoralscan 3 ) will be used for intraoral scanning & addition silicone impression material will be used for conventional impression technique. A master cast will            be poured with Types 4 gypsum product for conventional impression and will be scanned.

An Industrial scanner will be used for scanning  Reference model.

III. Measurements

All 3 STL files ( two intraoral scanner & one master model) will be superimposed with Reference model STL file and Interimplant distance deviation (2D) and coordinates (x, y, z),  will be assessed and compared among the two approaches.

All the data will be collected and Overall intergroup comparison among three groups will be done using One-way Anova ‘F’ test followed by Tukey’s post hoc test for pairwise intergroup                 comparison between each  groups.