Dental implant macro- and micro-shape should be designed to maximize the delivery of optimal favorable stresses in the surrounding bone region. The present study aimed to evaluate the stress distribution in cortical and cancellous bone surrounding two models of dental implants with the same diameter and length (4.0 × 11 mm) and different implant/neck design and thread patterns. Sample A was a standard cylindric implant with cylindric neck and V-shaped threads, and sample B was a new conical implant with reverse conical neck and with “nest shape” thread design, optimized for the favorable stress distribution in the peri-implant marginal bone region. Materials and methods: The three-dimensional model was composed of trabecular and cortical bone corresponding to the first premolar mandibular region. The response to static forces on the samples A and B were compared by finite element analysis (FEA) using an axial load of 100 N and an oblique load of 223.6 N (resulting from a vertical load of 100 N and a horizontal load of 200 N). Results: Both samples provided acceptable results under loadings, but the model B implant design showed lower strain values than the model A implant design, especially in cortical bone surrounding the neck region of the implant. Conclusions: Within the limitation of the present study, analyses suggest that the new dental implant design may minimize the transfer of stress to the peri-implant cortical bone.

Introduction. Short implants represent a valid alternative to bone regeneration techniques. In addition, metal-free prosthetic materials have several advantages for predictable rehabilitation. This case report is aimed at illustrating the advantages of fixed implant-prosthetic rehabilitation on short and ultrashort implants and metal-free prosthetic materials. Case report. A 66-year-old male patient with bone atrophy was treated with temporary denture placement performed based on a rapid protocol. Once the tissues after extractions matured and aesthetic/function was studied, short implants were prosthetically placed, and a fiber-reinforced composite (FRC) bar was digitally designed for a double full-arch fixed rehabilitation. The 2-year follow-up showed the absence of peri-implantitis signs and a stable occlusal relationship of prostheses. Discussion and conclusions. The FRC material has excellent aesthetic properties and is low cost with a simplified and fast workflow owing to digital dentistry methods. Further studies are still needed to confirm the effectiveness of long-term therapy; however, the combination of new minimally invasive surgery and prosthetic advances seems to be very promising.

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