An In Vitro Evaluation, on Polyurethane Foam Sheets, of the Insertion Torque (IT) Values, Pull-Out Torque Values, and Resonance Frequency Analysis (RFA) of NanoShort Dental Implants

Abstract

Objectives: The aim of this study was to investigate, in polyurethane foam sheets, the primary implant stability of a NanoShort implant compared to a self-condenser implant and to a standard, conventional implant. Materials and Methods: Three implant designs were evaluated in the present in vitro investigation: The Test implant (NanoShort), the Control A implant (self-condenser), and the Control B implant (standard design). The study was conducted by comparing the insertion torque values, the pull-out strength values, and the resonance frequency analysis (RFA) values of the Test and Control A and B implants inserted in polyurethane foam models of different thicknesses and densities. The foam densities were 10, 20, and 30 pounds per cubic foot (pcf). Three thicknesses of polyurethane foams (1, 2, 3 mm) were evaluated for a total of 640 experimental sites. Results: The Pearson correlation showed a moderate/strong correlation between all study groups (r > 0.3) for insertion torque and pull-out strength levels. Increased stability of the Test implants was obtained in 3 mm polyurethane sheets. The 2.5 and 3.5 mm Test implants presented good stability in 3 mm polyurethane sheets of 20–30 pcf densities. The Control implants showed better results compared to the Test implants in 1, 2, and 3 mm polyurethane sheets with densities of 10, 20, and 30 pcf. Conclusions: The NanoShort dental implant evaluated in this in vitro study showed a high level of stability in some experimental conditions, and could represent a useful tool, especially in the posterior mandible, as an alternative to vertical augmentation procedures.

Short vs. Standard Length Cone Morse Connection Implants: An In Vitro Pilot Study in Low Density Polyurethane Foam

“…The main reason for measuring the implant primary stability concerns the ability to predict the prognosis of the dental implant procedure. Comuzzi et al, in vitro, reported that in polyurethane foam, ISQ, insertion torque, and pull-out measuring provide the high repeatability and reproducibility that represent suitable indicators for implant stability [26]. In the present investigation, the implant primary stability was evaluated in a controlled reproducible study design and without the variables correlated to the use of animal bone.…”

“…Moreover, implants with a conical shape have a high stability even in blocks with a low density (D4 Density) and no differences were found between 5 mm and 6 mm long implants, where reasonable values of insertion torque and pull-out tests were found in short implants in both polyurethane densities. Comuzzi et al reported in vitro that a conical shape, rather than a cylindrical design, provided increased values of insertion torque and pull-out strength [26]. Thus, the ISQ values of both short implants were great, with an increased clinical sensation of the high stability of the implants.…”

Biomechanical Effects of a New Macrogeometry Design of Dental Implants: An In Vitro Experimental Analysis

“…Thus, we used a polyurethane foam density of 0.48 g/cm 3 in the cortical portion, considering that the mean of cortical bone density in human maxilla is 0.31 g/cm 3 for the posterior area and 0.45 g/cm 3 for the anterior area [29]. The densities of polyurethane foam used in the present study was of 15 pounds per cubic foot (pcf), corresponding to a density of 0.24 g/cm 3 (similar to the D3 bone type by Mish [30,31]); and 40 pcf, corresponding to 0.55 g/cm 3 (similar to D1 bone by Mish [30,31]). Cancellous bone receives and dissipates the forces generated by mastication after implant osseointegration more efficiently; however, to obtain the initial stability, cortical bone is more important because it has high density and resistance (~40% more) in comparison to medullary bone [10].…”

“…However, this method revealed the absence of mobility of the installed implant and not the bone quantity at the implant-bone interface [35,36]. The determination of good osseointegration is directly related to the absence of movement at the bone-implant interface in the different types of bone density [31]. Therefore, the lack of micromovement determined by a rigid primary stability and healing period free from external stimuli is originally a prerequisite for obtaining a satisfactory clinical result [37].…”

Primary Stability of Dental Implants in Low-Density (10 and 20 pcf) Polyurethane Foam Blocks: Conical vs Cylindrical Implants

“…The resonance frequency analysis (RFA) is a repeatable technique for implant stability evaluation that provides a measurement of the micromovements of the implant positioned in the bone site [13][14][15][16].…”