The Effect of Implant Abutment Surface Modifications on the Retention of Cement Retained Restoration: An In-Vitro Study

Abstract

Purpose: Retention is one of the most important factors for clinical success for any prosthesis. The most common technical complications of cement –retained implant supported fixed restorations are loss of retention. Surface modification of abutment and crown may increase the retentive strength of cemented crowns. Purpose of the present study was to compare the effect of implant abutment surface modifications on the retention of cement retained restoration.

Materials and Method: Forty solid titanium implant abutments (Top Implants) were divided into 4 groups. Ten abutments without surface modification (Group I) as supplied by the manufacturer, ten abutments with circumferential grooves (Group II) , ten abutments modified with an etchant (Group III) and ten abutments air-abraded with 50 microns aluminium oxide (Group IV)were used. Ni-Cr copings were fabricated for each abutment and luting cement (zinc phosphate cement) was used for cementing the copings. Using a Universal Testing Machine, tensile bond strength was recorded in Newton.

Results: Mean tensile bond strength of Group I, II, III and IV were found to be 300.97,491.41,339.80 and 317.05 Newton respectively. The values were statistically different from each other (p<0.001).

Conclusion: Abutments with circumferential retentive grooves showed the highest retention followed by abutments etched with an etchant, sandblasted abutments and then by abutments with no modifications.

Clinical Implications: Retention of the restoration depends on several factors like taper, surface area and height, surface finish and roughness as well as the luting agent used. Incorporation of circumferential retentive grooves, particle abrasion or acid etching can increase retention which is valuable especially in short clinical crown situations.