In VitroEvaluation of Bacterial Leakage at Implant-Abutment Connection: An 11-Degree Morse Taper Compared to a Butt Joint Connection

Abstract

Background and Aim. The geometry of implant-abutment interface (IAI) affects the risk of bacterial leakage and invasion into the internal parts of the implant. The aim of this study was to compare the bacterial leakage of an 11-degree Morse taper IAI with that of a butt joint connection. Materials and Methods. Two implants systems were tested (n = 10 per group): CSM (submerged) and TBR (connect). The deepest inner parts of the implants were inoculated with 2 μL of Streptococcus mutans suspension with a concentration of 108 CFU/mL. The abutments were tightened on the implants. The specimens were stored in the incubator at a temperature of 37°C for 14 days and the penetration of the bacterium in the surrounding area was determined by the observation of the solution turbidity and comparison with control specimens. Kaplan-Meier survival curve was traced for the estimation of bacterial leakage and the results between two groups of implants were statistically analyzed by chi-square test. Results. No case of the implant system with the internal conical connection design revealed bacterial leakage in 14 days and no turbidity of the solution was reported for it. In the system with butt joint implant-abutment connection, 1 case showed leakage on the third day, 1 case on the eighth day, and 5 cases on the 13th day. In total, 7 (70%) cases showed bacterial leakage in this system. Significant differences were found between the two groups of implants based on the incidence of bacterial leakage (p < 0.05). Conclusion. The 11-degree Morse taper demonstrated better resistance to microbial leakage than butt joint connection.

Contact analysis of gap formation at dental implant‐abutment interface under oblique loading: A numerical‐experimental study

“…27 Previous published studies also concluded that the conical connection had better resistance than nonconical ones against both mechanical deformation and bacterial invasion. 15,28,29 These rate between the two types of connection studied here was found clinically. 30 It appears that the size of the micro-gap does not relate to crestal bone loss either.…”

“…Some researchers measured the concentration of the penetrant, such as absorbance of the dye or bacterial count, to evaluate the volume of leakage. 15,28 However, the concentration of silver nitrate inside the implant was highly dependent on the drying time and the size of gap opening after loading. Using the data from micro-CT to quantify the volume of silver nitrate is possible but isolating the silver nitrate is very sensitive to the choice of the grayvalue threshold.…”

“…28 Another limitation of this study was that the volume of leakage was not quantified in the experiments. 15,28 However, the concentration of silver nitrate inside the implant was highly dependent on the drying time and the size of gap opening after loading. 15,28 However, the concentration of silver nitrate inside the implant was highly dependent on the drying time and the size of gap opening after loading.…”

“…However, the Morse taper connection has been shown to better prevent microleakage with smaller micro-gaps compared to the butt-joint and external connection. 14,15 The finite-element (FE) method is a powerful tool for analyzing the mechanical response, including stress and micro-gap formation, of dental implant systems. 16 Good agreement between FE simulation and in vitro measurements of the size of micro-gaps has been reported.…”

Effect of different implant placement depths on crestal bone levels and soft tissue behavior: A 5‐year randomized clinical trial

“…Implants with an internal taper connection and platformswitching can provide better protection against microbial leakage and soft tissue inflammation by reducing the microgap at the implant-abutment interface and increasing the distance to the bone crest, as well as allowing for a greater amount of connective tissue around the implant that functions as a cuff-like barrier (D'Ercole et al, 2014;Khorshidi, Raoofi, Moattari, Bagheri, & Kalantari, 2016;Lazzara & Porter, 2006;Tenenbaum, Schaaf, & Cuisinier, 2003). The subcrestal placement of dental implants may avoid the exposure of implant threads after initial physiologic bone remodeling and allow an adequate esthetic emergence profile for the prosthetic restoration (Koutouzis et al, 2014;Palaska, Tsaousoglou, Vouros, Konstantinidis, & Menexes, 2016;Vervaeke et al, 2018).…”