# Effect of the Diameter and Angulation Design of the Abutment Cementable Portion on Single Crown Retention: An In Vitro Experimental Study

## TL;DR

This study tested how abutment shape affects crown retention in dental implants, finding that certain designs provide stronger mechanical retention.

## Contribution

The study experimentally demonstrates that abutment angulation and diameter significantly influence cemented crown retention in vitro.

## Key findings

- The Ideale abutment with a 4.5 mm diameter showed the highest tensile strength (235.1 ± 9.785 Ncm).
- Abutments with smaller axial angulation and larger diameters provided superior mechanical retention.
- Statistically significant differences were observed between groups with varying abutment designs.

## Abstract

Objective

This study aimed to evaluate the influence of abutment geometry, specifically axial wall angulation and diameter, on the tensile strength of cemented prosthetic crowns using two types of abutments (Smart and Ideale) with identical heights but different diameters and angulation of the cementable abutment portion.

Materials and methods

Forty implant-abutment (IA) sets with a Morse taper connection were divided into four groups (n = 10): Sm1 (Smart, 3.5 mm), Id1 (Ideale, 3.3 mm), Sm2 (Smart, 4.5 mm), and Id2 (Ideale, 4.5 mm). Metal copings were cast using a nickel-chromium alloy and cemented with zinc phosphate cement under standardized conditions. Tensile testing was performed to determine the force required to remove each crown. Data were analyzed using parametric tests, with significance set at p < 0.05.

Results

All groups passed the Shapiro-Wilk normality test (p > 0.05). The Id2 group showed the highest mean tensile strength (235.1 ± 9.785 Ncm), followed by Sm2 (191.4 ± 8.870 Ncm), Id1 (150.8 ± 7.745 Ncm), and Sm1 (137.0 ± 7.666 Ncm). Statistically significant differences were observed between several group comparisons, indicating that both abutment angulation and diameter influence prosthesis retention.

Conclusion

Abutments with smaller axial angulation (Ideale model) and larger diameters demonstrated superior mechanical retention. These factors should be considered when selecting abutments for cemented implant-supported prostheses to ensure optimal retention and clinical performance.