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Background: There is limited knowledge on the effect of scan body (SB) material type, torque value, and sterilization on linear displacements of implant SBs. Purpose: To evaluate the effect of material type, torque value, and sterilization on linear displacements of SBs during screw tightening by using digital image correlation (DIC) analysis. Materials and Methods: One polyetheretherketone (PEEK, Zfx Intraoral Scan Body) and one titanium SB (Ti, MPS Zimmer Scanbody R1410) were tightened with 5 Ncm torque on two implants (Zimmer TSV ⌀4.7 mm) by using a digital torque limiting device. SBs' initial spatial positions relative to the implants were recorded by using 3D DIC technique. Measurements were repeated after initially increasing torque value to 10 Ncm and then to 15 Ncm, and these steps were repeated for a total of 10 PEEK and 10 Ti SBs on both implants (n = 20). All SBs were then sterilized 25 times by using an autoclave (STATIM 5000 S G4) according to manufacturer's recommendations and all measurements were repeated. Linear displacements on three axes were calculated for each SB with increasing torque values (from 5 to 10 Ncm and from 10 to 15 Ncm) before and after sterilization. SB displacements within each torque value–sterilization pair were compared by using Mann–Whitney U test, whereas Wilcoxon signed‐rank test was used to compare SB displacements within each material–torque value pair between conditions and within each material–sterilization pair between torque values (α = 0.05). Results: On x‐axis, PEEK SBs had higher displacements than Ti SBs (p < 0.001), whereas sterilization (p ≤ 0.028) and 15 Ncm torque application (p ≤ 0.006) led to higher displacements of PEEK SBs. On y‐axis, PEEK SBs had higher displacements than Ti SBs with 15 Ncm torque application (p ≤ 0.033). A total of 15 Ncm torque‐applied PEEK SBs and 10 Ncm torque‐applied Ti SBs had higher displacements after sterilization (p ≤ 0.028). Application of 15 Ncm torque led to higher displacements regardless of the material (p ≤ 0.002). On z‐axis, PEEK SBs had higher displacements (p ≤ 0.015), except for 10 Ncm torque‐applied sterilized SBs (p = 0.102). With 10 Ncm torque application, sterilization decreased the displacement values of PEEK SBs (p = 0.044). Greater displacements were observed with 10 Ncm torque‐applied Ti SBs before sterilization and 15 Ncm torque‐applied PEEK SBs after sterilization (p ≤ 0.033). Conclusions: Axial displacement of SBs was affected by material type, torque value, and sterilization. Ti SBs mostly had lower displacements than PEEK SBs. Application of 15 Ncm torque to tested PEEK SBs should be refrained from and a calibrated tightening tool may enable the application of 10 Ncm or lower torque values for lower displacements. Sterilization generally increased PEEK SB displacements. [ABSTRACT FROM AUTHOR]

Purpose: To measure and compare the three-dimensional (3D) position of nine different abutments manufactured by different manufacturers after repeated torqueing on an internal-hexagon implant. Materials and Methods: Nine tapered implants were placed into an acrylic resin block. Five specimens each of nine different abutments (n = 45) were placed into one of nine implants. The abutments were hand- tightened and then torqued to the manufacturer-recommended torque of 30 Ncm. After 10 minutes, 30 Ncm of torque was reapplied. Another 10 minutes elapsed before testing was completed. Images were recorded in 12-second intervals. The spatial relationship of the abutments to the resin block was determined using 3D digital image correlation. Commercial image correlation software was used to analyze the displacements. Mean displacements for the abutments were calculated in three dimensions and overall for both torque applications. Statistical comparisons were done with a t test and a step-down Bonferroni correction. Results: The overall 3D displacement of the Atlantis Titanium abutment after the second applied torque was significantly greater than that of two of the eight other abutments. Displacement in all three dimensions for the Atlantis Titanium abutment changed direction between the first and second torque applications. All abutments moved further in the same direction except for the Atlantis Titanium abutment, which moved back toward its original hand-tightened position horizontally after the second torque application. Conclusion: Re-torqueing of abutments after a 10-minute interval leads to minor displacement of varying degrees between the abutment and a tapered implant. A potential effect of embedment relaxation and/or manufacturing errors should be taken into consideration when selecting an abutment for a cement-retained crown on a tapered implant. Accordingly, clinicians may benefit from adjusting cement-retained implant crowns after re-torqueing the abutments to prevent potential occlusal and interproximal contact problems. [ABSTRACT FROM AUTHOR]

one of the nine implants. Initially, the abutments were torqued to 20 Ncm to represent hand tightening. Abutments were tightened to 30 Ncm using a torque driver as recommended by the manufacturer for final seating. Images were recorded in 12-second intervals for approximately 10 minutes after the torque was applied. The spatial relationship of the abutments to the resin block was determined using three-dimensional digital image correlation. Commercial image correlation software was used to analyze the displacements. Mean displacements for the nine different abutments were calculated in ail three dimensions and for overall displacement in space. A t test with a step-down Bonferroni correction was used for a pairwise comparison of each abutment's mean displacements to the other abutments to determine statistical differences (a = .05). Results: The Atlantis titanium, Inclusive titanium, and Legacy zirconia abutments showed mean displacements that were statistically significantly higher than other abutments in the horizontal direction. The overall three-dimensional displacement of the Atlantis titanium abutment after an applied 30-Ncm torque was significantly higher than that of six of the other eight abutments (P < .0144). Conclusion: Within the limitations of this in vitro study, the Zimmer PSA demonstrated less displacement between hand tightening and torqueing than the Atlantis titanium or Inclusive titanium abutments when used to restore a TSV implant. [ABSTRACT FROM AUTHOR]

Purpose: Internal conical implant-abutment connections without platforms may lead to axial displacement of crowns during screw tightening. This displacement may affect proximal contacts, incisal edge position, or occlusion. This study aimed to measure the displacement of screw-retained single crowns into an implant in three dimensions during screw tightening by hand or via torque driver. Material and Methods: A stereolithic acrylic resin cast was created using computed tomography data from a patient missing the maxillary right central incisor. A 4.0- × 11-mm implant was placed in the edentulous site. Five porcelain-fused-to-metal single crowns were made using "cast-to" abutments. Crowns were tried on the stereolithic model, representing the patient, and hand tightened. The spatial relationship of crowns to the model after hand tightening was determined using three-dimensional digital image correlation (3D DIC), an optical measurement technique. The crowns were then tightened using a torque driver to 20 Ncm and the relative crown positions were again recorded. Testing was repeated three times for each crown, and displacement of the crowns was compared between the hand-tightened and torqued states. Commercial image correlation software was used to analyze the data. Mean vertical and horizontal crown displacement values were calculated after torqueing. The interproximal contacts were evaluated before and after torquing using an 8-?m aluminum foil shim. Results: There were vertical and horizontal differences in crown positions between hand tightening and torqueing. Although these were small in magnitude, detectable displacements occurred in both apical and facial directions. After hand tightening, the 8-?m shim could be dragged without tearing. However, after torque tightening, the interproximal contacts were too tight and the 8-?m shim could not be dragged without tearing. Conclusion: Differences between hand tightening and torque tightening should be taken into consideration during laboratory and clinical adjustments to prevent esthetic and functional complications. [ABSTRACT FROM AUTHOR]

Purpose To compare the displacements of CAD–CAM zirconia and titanium abutments into different internal connection systems after torquing. Methods OsseoSpeed EV and OsseoSpeed TX implants (n = 10) were placed in resin blocks. Zirconia and titanium abutments (n = 5) were first hand tightened and then tightened to the recommended torque (20 N cm for TX and 25 N cm for EV). Displacements of abutments between screw tightening by hand and torque driver was measured using three-dimensional digital image correlation (3D DIC) technique. Displacements were measured in U (front/back), V (into/outward), W (right/left) directions and 3-dimensionally (3D). ANOVA with restricted maximum likelihood estimation method was used to analyze the data. Bonferroni-corrected t tests was used to determine the statistical differences ( α = 0.05). Results 3D displacement of zirconia and titanium abutments was significantly greater in OsseoSpeed EV implant (P < 0.001). Displacement of zirconia and titanium abutments was not significantly different within implant systems, 3D (P ≥ 0.386) and in each direction (P ≥ 0.382). In U and V directions, zirconia and titanium abutments displaced significantly more towards negative in OsseoSpeed EV implant (P < 0.019). Within the OsseoSpeed TX system, abutments displaced significantly more in V direction compared to the U and W (P ≤ 0.005), and within the Osseospeed EV system, abutment displacements were significantly different amongst directions and displacements in V were the greatest (P < 0.001). Conclusion Abutments displaced more in the implant that required higher torque values to tighten the abutment. The amount of displacement in both systems was clinically small. Abutment material did not affect the magnitude of displacement. [ABSTRACT FROM AUTHOR]