Retention System and Splinting on Morse Taper Implants in the Posterior Maxilla by 3D Finite Element Analysis

Abstract

The purpose of this study was to evaluate different retention systems (cement-or screw-retained) and crown designs (non-splinted or splinted) of fixed implant-supported restorations, in terms of stress distributions in implants/components and bone tissue, by 3-dimensional (3D) finite element analysis. Four 3D models were simulated with the InVesalius, Rhinoceros 3D, and SolidWorks programs. Models were made of type III bone from the posterior maxillary area. Models included three 4.0-mm-diameter Morse taper (MT) implants with different lengths, which supported metal-ceramic crowns. Models were processed by the Femap and NeiNastran programs, using an axial force of 400 N and oblique force of 200 N. Results were visualized as the von Mises stress and maximum principal stress (σ max ). Under axial loading, there was no difference in the distribution of stress in implants/components between retention systems and splinted crowns; however, in oblique loading, cemented prostheses showed better stress distribution than screwed prostheses, whereas splinted crowns tended to reduce stress in the implant of the first molar. In the bone tissue cemented prostheses showed better stress distribution in bone tissue than screwed prostheses under axial and oblique loading. The splinted design only had an effect in the screwed prosthesis, with no influence in the cemented prosthesis. Cemented prostheses on MT implants showed more favorable stress distributions in implants/components and bone tissue. Splinting was favorable for stress distribution only for screwed prostheses under oblique loading.

Should the restoration of adjacent implants be splinted or nonsplinted? A systematic review and meta-analysis

“…5,28,36 This might be because of the biomechanical differences between splinted and nonsplinted implants, 8 in which the splinted restoration has tended to share load among the screw components of the restoration. 8,42,43 Clinically, the splinting of posterior implants could be beneficial for reducing loss of retention. 5,36 To avoid indirect comparison, only studies that offered data of splinted and nonsplinted restorations were selected.…”

Splinted and Nonsplinted Crowns with Different Implant Lengths in the Posterior Maxilla by Three-Dimensional Finite Element Analysis

“…Furthermore, cemented crowns were simulated in this study because they exhibit better biomechanical behavior with Morse taper implants [16] and contribute to greater preservation of the bone tissue, compared with the screwed crown [22]. …”

“…This may contribute to decreasing the stress on implants that are subject to high masticatory forces, such as those placed in the molar region. The higher stress in the molar may be attributed to increases in the occlusal table with four cusps [16]. In this context, the splinted crowns of implants with a greater occlusal table is recommended because it may promote better stress distribution, thus decreasing the complication rates such as loosening/fracture screw fixation and abutment [7], and the risk for resorption of cortical bone tissue [8], in the maxillary posterior region, which exhibit higher risk of implant failure [24].…”

“…Von Mises analysis was used to assess the stress distribution in implant/abutment/crown, whereas the cortical bone tissue was evaluated using maximum principal stress and are distinguished between tensile stresses (positive values) and compressive stresses (negative values). The unit of measurement for both analyses in the present study was megapascals (MPa) [15, 16]. …”

Biomechanical analysis of different implant-abutments interfaces in different bone types: An in silico analysis

“…These results may also could be related to the different prosthesis fixation methods used [20]. MT implants for rehabilitation of single-unit crown are recommended with cement-retained prosthesis [21], mainly with a solid abutment (onepiece) without screw fixation. These factors could contribute the favorable results for MT implants compared to EH implants from the same diameter.…”