Comparison of the Morse Cone Connection with the Internal Hexagon and External Hexagon Connections Based on Microleakage – Review

Abstract

The gap formed at the abutment-implant interface brings about a bacterial colonization. In addition, a bacterial reservoir can be established within the implant. The build-up of microorganisms around the implant can cause soft tissue infections and bone loss around the implant, which can lead to implant failure. Our literature review aimed to evaluate the infiltration at the implant-abutment interface, comparing the Morse cone connection with the external hexagon and internal hexagon connections. A literature search using the PubMed database was performed on March 24, 2021. The search terms were combinations of “Morse cone” or “Morse taper” with each of the following terms (individually): “microleakage”, “leakage”, “infiltration”, and “penetration”. The inclusion criterion was in vitro studies comparing the Morse cone with the external hexagon and/or internal hexagon, based on infiltration at the implant-abutment interface. The exclusion criterion was the evaluation of microleakage at the implant-abutment interface after applying a sealant over this region. The search was expanded as needed. There was no limit on the year of publication, and only articles written in English were included. In addition, references cited in included articles were also included in this review when they were appropriate. This literature review concluded that, in most cases, the microleakage in the Morse cone connection was lower when compared with the external hexagon and internal hexagon connections.

Marginal Bone Loss Compared in Internal and External Implant Connections: Retrospective Clinical Study at 6-Years Follow-Up

“…Marginal resorption was significantly higher around externally connected implants than in internal ones ( p < 0.001), and the null hypothesis was rejected. Similar results, supported by several authors [ 34 , 35 ], were obtained by Kim et al [ 63 ] in their retrospective clinical study with 4–12 years of follow-up in which they compared the marginal bone loss between external-connection and internal-connection dental implants in posterior areas. A total of 170 patients with 355 implants were included in the study, of which 206 were externally connected and 149 were internally connected.…”

“…As lateral forces are transmitted at the contact point between the implant and abutment, the risk of loosening and screw breakage is increased by generating micromovements that induce bone remodeling [29][30][31]. In addition, the presence of gaps on the implant-abutment surface can cause microleakage and bacterial accumulation, which can compromise the dental implant success [32][33][34][35][36][37].…”

Case Report of a Dental Implant with Conometric Abutment–Prosthetic Cap Connection: Advanced High-Resolution Imaging and Peri-Implant Connective Tissue Performance

“…Less bacterial leakage and a lower rate of infiltration were found in conometric connections when compared to hexagon connections. Moreover, other microbiological studies confirmed a very low percentage of bacterial leakage in conometric connection Cone Morse implants [37,38]. These results could, most likely, be related to a very precise fit between the two components, as was shown through the use of micro-CT in the present study.…”

Antimicrobial Efficacy and Permeability of Various Sealing Materials in Two Different Types of Implant–Abutment Connections

“…They also concluded that there was a tendency toward a better sealing efficacy against S. aureus for internal conical and hexagonal connections. In a recent review by Bittencourt et al [ 23 ], it was concluded that microleakage in the Morse conical connection was lower when compared with the internal and external hexagon connections. According to the literature, perfect sealing at the IAC has not been provided by any implant system, and a complete hermetic seal is not yet achievable [ 24 ].…”