Abstract
The fit of the implant-abutment interface was assessed by the metallographic technique and by scanning electron microscopy (SEM), using solid abutment types at different torque levels. Forty Morse taper connections and forty solid abutments were used at different torque levels (repeated after 10 minutes) in the following groups (n = 10): 25 Ncm (group g1), 30 Ncm (group g2), 35 Ncm (group g3), and 40 Ncm (group g4). The samples were embedded in a metallographic resin, sectioned lengthwise, and polished. SEM images were used to measure the linear contacts and the fits between abutments and the internal walls of the implant. The overall mean gap and standard deviation were as follows: 9.0 ± 1.36 µm for group g1, 7.9 ± 2.81 µm for group g2, 2.0 ± 0.76 µm for group g3, and 0.3 ± 0.40 µm for group g4. A significant difference was observed in the average fit values between the groups (p < 0.05). The linear area of contact between the abutment and the implant increased as torque augmented. This study demonstrated that higher insertion torque values in a conical internal connection increase the fit (contact) of the implant-abutment interface.
Highlights
Dental implants have been used extensively in oral rehabilitation for the replacement of one or more missing teeth with satisfactory survival rates.[1,2,3] adverse biological responses and prosthetic restoration complications can occur
Given the long-term successful follow-ups of Morse taper implants,[15,16] this study aimed to evaluate the torque level related to the fit of the implant-abutment interface
As reported in other studies, to limit the effect of sedimentation on the screws, which leads to preload reductions, the components were retightened with the respective torque values 10 minutes after the initial torque was applied.[17]
Summary
Dental implants have been used extensively in oral rehabilitation for the replacement of one or more missing teeth with satisfactory survival rates.[1,2,3] adverse biological responses and prosthetic restoration complications can occur. The stability of the implant-abutment interface is an important factor that influences load distribution to the marginal bone. The most frequent complications arising from misfits of the implant-abutment interface include: a) biological complications that include increased load transfer to the bone, bone loss, and development of microflora in the micro-gap between implant and abutment[4,5,6] and b) prosthetic complications that include screw loosening or fracture and implant loss.[7]. Due to the absence of a periodontal ligament, implants are incapable of readily adapting to stresses caused by poorly fitted restorations.[8] Micro-gaps can form in the abutment/implant interface due to loose abutment fixtures, favouring bacterial invasion and mechanical problems.[9] In every implant system, the efficiency of the fixture joint system depends on several factors, such as component design, connection
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