Influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with a lingual slot

Abstract

PURPOSECement-retained implant prostheses can lack proper retrievability during repair, and residual cement can cause peri-implantitis. The purpose of this in vitro study was to evaluate the influence of abutment height and convergence angle on the retrievability of cement-retained implant prostheses with lingual slots, known as retrievable cement-type slots (RCS).MATERIALS AND METHODSWe fabricated six types of titanium abutments (10 of each type) with two different heights (4 mm and 6 mm), three different convergence angles (8°, 10°, and 12°), a sloped shoulder margin (0.6 mm depth), a rectangular shape (6 mm × 6.5 mm) with rounded edges, and a rectangular ledge (2 mm × 1 mm) for the RCS. One monolithic zirconia crown was fabricated for each abutment using a dental computer-aided design/computer-aided manufacturing system. The abutments and crowns were permanently cemented together with dual-curing resin cement, followed by 24 hours in demineralized water at room temperature. Using a custom-made device with a slot driver and torque gauge, we recorded the torque (N·cm) required to remove the crowns. Statistical analysis was conducted using multiple regression analysis and Mann-Whitney U tests (α=.05).RESULTSRemoval torques significantly decreased as convergence angles increased. Multiple regression analysis showed no significant interaction between the abutment height and the convergence angle (Durbin-Watson ratio: 2.186).CONCLUSIONWithin the limitations of this in vitro study, we suggest that the retrievability of cement-retained implant prostheses with RCS can be maintained by adjusting the abutment height and convergence angle, even when they are permanently cemented together.

Effect of Abutment Geometry and Luting Agents on the Vertical Marginal Discrepancy of Cast Copings on Implant Abutments: An In Vitro Study

“…In addition, considering the abutment wall (cylindrical vs. hexagonal), the cast copings cemented on hexagonal 4 mm abutments showed the highest VMD using zinc oxide noneugenol and glass ionomer. Previous studies [22][23][24] showed that the removal forces of cemented copings depend on abutment geometry and luting agents. us, it seems that these two variables are related to technical factors and implant treatment.…”

In Vitro Simulation of Dental Implant Bridges Removal: Influence of Luting Agent and Abutments Geometry on Retrievability

“…Bridges 1 and 2 are the only ones with non-tapered abutments on both ends, and the results are in accordance with the established relationship between the abutment taper angle and the coping retrievability. Indeed, it is well-known, from both experimental [30][31][32] and clinical [29] studies, that the abutment retentiveness increases with its height and decreases with its taper angle. On the other hand, bridge 4 was the only one with two 5 mm high and tapered abutments (i.e., a poorly retentive geometry), and it behaved, as expected, as the least retentive one with all cements.…”

Types of retention for implant-supported fixed prosthesis: a narrative literature review

“…Choi et al demonstraram que a recuperabilidade da prótese final pode ser obtida pelo controle do ângulo de convergência do pilar de acordo com sua altura e presença de slots linguais. Recomendou-se a utilização de cimentos permanentes 17 , porém as limitações do desenho do estudo incapacitam a avaliação de peri-implantite e consequências biológicas de tal aspecto.…”