The aim of this study is to evaluate the effectiveness of the implant diameter and length on force dissemination of tooth-implant and implant retained fixed restorations. A finite analysis model was used via a 3D simulation of a unilateral mandibular Kennedy Class I arch. Through thresholding the resultant assembly, a region of interest was selected from the CT scan. Details of the diameter (D) and length (L) of implant were introduced. Ds used were 3.7, 4.7, and 5.7, while Ls used were 10, 11.5, and 13. The constant was the use of rigid connectors in both designs (implant–implant and implant–tooth fixed partial dentures) and the mesial implant (D 3.7 and L 11.5).  Stress in cancellous bone around mesial abutment, which is the second premolar in tooth-implant FPD and mesial implant in the implant-implant fixed partial denture (FPD), revealed that the stress was significantly lower in tooth-implant FPD when compared to implant-implant FPD (21.1±0.00 versus 46.1±0.00, p <0.001). Stress distribution in the bone around any implant depends on several factors such as diameter, length, and tooth-implant vs. implant-implant support. The implant diameter was more significant for improved stress distribution than implant length. A moderate increase in the length of the implant consequently reduced stress.

Purpose To investigate the significance of the connector type on stress dissemination within the tooth‐implant‐supported fixed dental prostheses in the mandibular posterior region with different combinations of implant diameter and length by means of finite element analysis (FEA). Materials and Methods Six models of different designs for tooth‐implant fixed dental prosthesis (FDPs) were simulated and divided into two main groups. Implant lengths were 10, 11.5, and 13 mm while implant diameters were 3.7, 4.7, and 5.7 mm. The main difference between the groups was the connector type. Models were evaluated using 3D FEA (Solidworks Premium 2018 × 64 Edition). Group A tooth‐implant FDPs (5.7 mm × 10 mm) had a mesial and distal rigid connector while group B tooth‐implant FDPs (3.7 mm × 10 mm, 3.7 mm × 11.5 mm, 3.7 mm × 13 mm, 4.7 mm × 10 mm and 5.7 mm × 10 mm) had a mesial non‐rigid connector in their design between the pontic and the tooth. Models were analyzed to determine the magnitude of von Misses Stresses at six specific zones (fixed dental prosthesis, bone around distal implant, bone around tooth, cementum, periodontal ligament, implant) under vertical occlusal loading of 100 N after meshing and assigning the material properties. Results Stress values around the supporting bone were significantly higher in Group B (tooth‐implant FDP with non‐rigid connection) when compared to Group A (tooth‐implant FDP with rigid connection). Also, the stresses measured at the FDP level showed that the rigid connection group (5.7 mm × 10 mm) exhibited 26% lower stress values when compared to the non‐rigid group (5.7 mm × 10 mm). Conclusions Implant‐tooth FDPs with rigid connector design using the combination of implant diameter and length (5.7 mm × 10 mm) demonstrated a better design modality thus predicting a higher success rate and more longevity than using the non‐rigid connection option.