Bacterial translocation and microgap formation at a novel conical indexed implant abutment system for single crowns

Abstract

Objectives A conometric concept was recently introduced in which conical implant abutments hold the matching crown copings by friction alone, eliminating the need for cement or screws. The aim of this in vitro study was to assess the presence of microgap formation and bacterial leakage at the Acuris conometric restorative interface of three different implant abutment systems. Material and methods A total of 75 Acuris samples of three implant-abutment systems (Ankylos, Astra Tech EV, Xive) were subjected to microbiological (n = 60) and scanning electron microscopic (SEM) investigation (n = 15). Bacterial migration into and out of the conical coupling system were analyzed in an anaerobic workstation for 48, 96, 144, and 192 h. Bacterial DNA quantification using qrt-PCR was performed at each time point. The precision of the conometric coupling and internal fit of cemented CAD/CAM crowns on corresponding Acuris TiN copings were determined by means of SEM. Results qrt-PCR results failed to demonstrate microbial leakage from or into the Acuris system. SEM analysis revealed minute punctate microgaps at the apical aspect of the conometric junction (2.04 to 2.64 µm), while mean cement gaps of 12 to 145 µm were observed at the crown-coping interface. Conclusions The prosthetic morse taper connection of all systems examined does not allow bacterial passage. Marginal integrity and internal luting gap between the ceramic crown and the coping remained within the clinically acceptable limits. Clinical relevance Conometrically seated single crowns provide sufficient sealing efficiency, relocating potential misfits from the crown-abutment interface to the crown-coping interface.

The Conometric Connection for the Implant-Supported Fixed Prosthesis: A Narrative Review

“…It was demonstrated through in vitro microbiological testing that there is no presence of bacteria either living or dead in the portions inside the prosthetic conometric connection. This can, therefore, be considered an acceptable prosthetic component from this point of view [6,26]. Scanning electron microscope (SEM) analysis of the marginal area showed minute and punctual micro-gaps (1.67-2.04 µm), although planar surfaces were in intimate contact [26].…”

“…This can, therefore, be considered an acceptable prosthetic component from this point of view [6,26]. Scanning electron microscope (SEM) analysis of the marginal area showed minute and punctual micro-gaps (1.67-2.04 µm), although planar surfaces were in intimate contact [26]. The average gaps between the conometric connection of the analyzed systems vary between 2 and 3 µm; considerably greater is the discrepancy between the hood and the prosthetic crown, which has a gap that can reach up to 145 µm: this is a virtual gap; in fact, with the cementation procedures, the latter is filled [26].…”

“…Scanning electron microscope (SEM) analysis of the marginal area showed minute and punctual micro-gaps (1.67-2.04 µm), although planar surfaces were in intimate contact [26]. The average gaps between the conometric connection of the analyzed systems vary between 2 and 3 µm; considerably greater is the discrepancy between the hood and the prosthetic crown, which has a gap that can reach up to 145 µm: this is a virtual gap; in fact, with the cementation procedures, the latter is filled [26]. It is clear from the literature that a complete seal can be provided when the conometric connection is activated with a force of 50 N [27].…”

Evaluation of a platform‐switched Morse taper connection for all‐on‐four or six treatment in edentulous or terminal dentition treatment: A retrospective study with 1–8 years of follow‐up

“…17,18 Micro gaps and micromotion at the connection between the abutment and the implant are common problems in two-stage systems and may lead to local inflammation and bone loss. 19,20 Studies have suggested that the platform switch technique can help prevent marginal bone loss (MBL) around the implants. [21][22][23][24][25][26][27] The balanced base abutment is a commonly used component in the Ankylos implant system for edentulous patients.…”

“…The abutment is an important component of the implant system, and the design of abutment affects the soft and hard tissue around the implant 17,18 . Micro gaps and micromotion at the connection between the abutment and the implant are common problems in two‐stage systems and may lead to local inflammation and bone loss 19,20 . Studies have suggested that the platform switch technique can help prevent marginal bone loss (MBL) around the implants 21–27 .…”