Albaijan Refal, Vohra Fahim, Alnassar Talal M, Robaian Ali, Alnafaiy Sarah M, Alzahrani Khaled M, Alnasser Abdullah H, Alshehri Abdullah, Alkahtani Rawan, Alrahlah Ali, Gufran Khalid
Department of Prosthetic Dental Sciences, College of Dentistry, Prince Sattam bin Abdulaziz University, Alkharj, Saudi Arabia.
Division of Prosthodontics, Department of Restorative Dentistry, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
J Prosthodont. 2025 Jul 29. doi: 10.1111/jopr.70012.
The purpose of this in vitro study was to assess the surface micro-roughness and de-torque measurement of selective laser melting (SLM) implant abutments in comparison to cast and machined implant abutments.
Forty abutment specimens were divided equally into four groups (n = 10) as follows: machined titanium (Ti) abutments (Control), cast cobalt-chromium (CoCr) abutments, SLM-CoCr abutments, and SLM-Ti abutments. Fabricated abutments were assessed for surface micro-roughness using a 3D optical noncontact surface microscope (Contour GT-K 3D Optical Microscope, Bruker, Tucson, Arizona, USA). In addition, abutment displacement was assessed using de-torque values. The abutments were torqued to the implant at 30 Ncm and retorqued after 15 min according to the manufacturer's recommendation using a Tohnichi BTGE digital torque gauge. After 2 min, preload reverse torque values (RTVs) measurements were performed. Before cyclic loading, the abutments were retorqued to the implant at 30 Ncm, and metal crowns were cemented to the abutments with a temporary cement (CharmTemp EU; DentKist Inc., Korea) using a 6 kg force applied for 10 min. After 24 h of cementation, the specimens were subjected to 5 kg of loads for 600,000 cycles at a frequency of 1 Hz using the chewing simulation machine. Immediately after the cyclic loading, the postload-RTVs were measured. This was performed to identify the comparative effect of fabrication techniques on the reverse torque difference (RTD). Data was assessed using Analysis of variance (ANOVA) and Tukey Post hoc comparison tests for all the variables. Pearson correlation was used to assess dependence between independent variables (surface roughness) and dependent variables (de-torque values).
SLM abutments were compared with the cast and machined abutments in the surface micro-roughness and de-torque values. SLM-Ti abutments showed a significantly rougher surface (p < 0.05) among the study groups with a mean Ra of 2.24 ± 0.36 µm. SLM-CoCr abutments were smoother than cast abutments with mean Ra of 1.30 ± 0.11 µm and 1.58 ± 0.17 µm, respectively (p < 0.05). For the de-torque test, mean preload RTVs of SLM-Ti (23.39 ± 3.74 Ncm) and SLM-CoCr (19.73 ± 1.97 Ncm) presented comparable (p > 0.05) results with cast CoCr (22.87 ± 2.21 Ncm). However, only the mean postload RTVs were significantly lower (p < 0.05) in SLM-CoCr (16.36 ± 3.90 Ncm) than machined Ti (20.52 ± 2.23 Ncm) abutments. There was no significant difference between the groups for RTDs (p > 0.05).
SLM CoCr abutments showed a smoother surface than cast abutments, while SLM Ti abutments had the highest surface roughness in comparison with other groups. No significant difference was found between the groups for RTDs. No significant correlation was found between the surface roughness and postload RTVs. However, a negative correlation was found between surface roughness and RTDs.
本体外研究的目的是评估选择性激光熔化（SLM）种植体基台与铸造和加工种植体基台相比的表面微观粗糙度和脱扭矩测量。
40个基台标本平均分为四组（n = 10），如下：加工钛（Ti）基台（对照组）、铸造钴铬（CoCr）基台、SLM-CoCr基台和SLM-Ti基台。使用3D光学非接触表面显微镜（Contour GT-K 3D光学显微镜，布鲁克，美国亚利桑那州图森）评估制造的基台的表面微观粗糙度。此外，使用脱扭矩值评估基台位移。根据制造商的建议，使用东日BTGE数字扭矩计将基台以30 Ncm的扭矩拧紧到种植体上，并在15分钟后重新拧紧。2分钟后，进行预加载反向扭矩值（RTV）测量。在循环加载之前，将基台以30 Ncm的扭矩重新拧紧到种植体上，并使用6 kg的力施加10分钟，用临时粘结剂（CharmTemp EU；韩国DentKist公司）将金属冠粘结到基台上。粘结24小时后，使用咀嚼模拟机以1 Hz的频率对标本施加5 kg的载荷，持续600,000次循环。循环加载后立即测量加载后RTV。这样做是为了确定制造技术对反向扭矩差（RTD）的比较效果。使用方差分析（ANOVA）和Tukey事后比较检验对所有变量进行数据评估。使用Pearson相关性评估自变量（表面粗糙度）和因变量（脱扭矩值）之间的依赖性。
将SLM基台与铸造和加工基台在表面微观粗糙度和脱扭矩值方面进行比较。在研究组中，SLM-Ti基台的表面明显更粗糙（p < 0.05），平均Ra为2.24 ± 0.36 µm。SLM-CoCr基台比铸造基台更光滑，平均Ra分别为1.30 ± 0.11 µm和1.58 ± 0.17 µm（p < 0.05）。对于脱扭矩测试，SLM-Ti（23.39 ± 3.74 Ncm）和SLM-CoCr（19.73 ± 1.97 Ncm）的平均预加载RTV与铸造CoCr（22.87 ± 2.21 Ncm）呈现出可比的结果（p > 0.05）。然而，只有SLM-CoCr（16.36 ± 3.90 Ncm）的平均加载后RTV显著低于加工Ti（20.52 ± 2.23 Ncm）基台（p < 0.05）。各组之间的RTD没有显著差异（p > 0.05）。
SLM CoCr基台的表面比铸造基台更光滑，而SLM Ti基台与其他组相比表面粗糙度最高。各组之间的RTD没有显著差异。表面粗糙度与加载后RTV之间没有显著相关性。然而，表面粗糙度与RTD之间存在负相关。
