Author ORCID Identifier

https://orcid.org/0009-0008-6691-1479

Semester

Summer

Date of Graduation

2024

Document Type

Thesis

Degree Type

MS

College

School of Dentistry

Department

Restorative Dentistry

Committee Chair

Arif Salman Abdul Shakore

Committee Co-Chair

Shelby Alexander

Committee Member

Shelby Alexander

Committee Member

R Constance Wiener

Abstract

Rubinya Sundar Iyer, B.D.S.

Objective:

The purpose of this study is to compare the accuracy of the reproduction of three-dimensional implant position of implant definitive casts fabricated from impressions of Coded Healing Abutments (CHAs) and compare it to that of implant definitive casts fabricated by a conventional implant impression technique at two different inter-implant distances of 12mm and 15mm for parallelly placed implants.

Materials and Methods:

Two partially edentulous Styrofoam models were used to fabricate the master models with implant analogs placed 12mm and 15mm apart. Laboratory Scan Bodies (LSBs) were inserted into the implant analogs in the models and were scanned using a benchtop scanner to obtain the master scans. For the analog test groups, impression copings were connected to the analogs, and four conventional open-tray PVS impressions were made for each of the two models M12 and M15, for a total of 8 impressions, from which test models TA12 and TA15 were fabricated. LSBs were inserted into the analogs in the test models to obtain test scans for these groups. For the CHA test groups, CHAs were connected to the implant analogs in M12 and M15. PVS impressions were made, four for each of the two groups, for a total of eight impressions from which eight total models were obtained. These models were scanned, and the .stl files were sent to the dental laboratory, where printed models with implant analogs were obtained, constituting the test groups TC12 and TC15. LSBs were inserted into the analogs on these models, and test scans were obtained for these groups. A metrology software was utilized to superimpose all the test scans onto their corresponding master scans to evaluate the distance and angular deviations at three locations/ positions. Data were analyzed to evaluate statistical significance between TA12 and TC12 and between TA15 and TC15 for distance and angular deviations.

Results:

The distance deviation values ranged from -7.9 to 42.9 µm for TA12 and -7.2 to 54.5 µm for TC12, and from -7.7 to 16.7 µm for TA15 and -13.6 to 15.5 for TC15. The angular deviation values ranged from -0.5930 to 0.3759 degrees for TA12 and -0.6325 to 2.1026 degrees for TC12, and from -0.1458 to 0.8850 degrees for TA15 and -1.2057 to 1.8628 degrees for TC15. Wilcoxon tests revealed no statistically significant differences in the distance and angular deviations between TA12 and TC12. Two-sample t-tests revealed no statistically significant differences in the distance deviations between TA15 and TC15 but revealed a statistically significant difference in the inter-implant angular deviation between TA15 and TC15 (p=0.014).

Conclusions:

For parallelly placed implants, at both the inter-implant distances evaluated, the distance deviations in the implant positions were similar between the CHA and analog test groups. The inter-implant angular deviation was higher for the CHA test group compared to the analog test group when the inter-implant distance was 15mm; however, the extent of clinical significance of this difference is unknown.

Embargo Reason

Publication Pending

Available for download on Saturday, August 02, 2025

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