Individualized, serial production of innovative implants is a major area of application for additive manufacturing in the field of medicine. Individualized healthcare requires faster delivery of the implant to the clinic or hospital facility. The total manufacturing process, including data generation using 3D drawings, imaging techniques, 3D printing and post-processing, usually takes up to a week, especially implants from risk class III, which requires qualified equipment and a validated process. In this study, we describe how to develop a new biomechanical model for dental implants from its conception for the patent to the final product which is ready to be manufactured using additive manufacturing. The benefits and limitations of titanium metal printing for dental implant prototypes are presented by the authors.
A new biomechanism, Bioactive Kinetic Screw (BKS) for screws and bone implants created by the first author, is presented using a bone dental implant screw, in which the bone particles, blood, cells, and protein molecules removed during bone drilling are used as a homogeneous autogenous transplant in the same implant site, aiming to obtain primary and secondary bone stability, simplifying the surgical procedure, and improving the healing process. The new BKS is based on complex geometry. In this work, we describe the growth factor (GF) delivery properties and the in situ optimization of the use of the GF in the fixation of bone screws through a dental implant. To describe the drilling process, an explicit dynamic numerical model was created, where the results show a significant impact of the drilling process on the bone material. The simulation demonstrates that the space occupied by the screw causes stress and deformation in the bone during the perforation and removal of the particulate bone, resulting in the accumulation of material removed within the implant screw, filling the limit hole of the drill grooves present on the new BKS.
A new mechanism, applied in this study as a biomechanical device, known as a Bioactive Kinetic Screw (BKS) for bone implants is described. The BKS was designed as a bone implant, in which the bone particles, blood, cells, and protein molecules removed during bone drilling are used as a homogeneous autogenous transplant at the same implant site, aiming to optimize the healing process and simplify the surgical procedure. In this work, the amount of bone that will be compacted inside and around the new biomechanism was studied, based on the density of the bone applied. This study allows us to analyze the average bone density in humans (1.85 mg/mm3 or 1850 µg/mm³) with four different synthetic bone densities (Sawbones PCF 10, 20, 30 and 40). The results show that across all four different synthetic bones densities, the bone within the new model is 3.45 times denser. After a pilot drill (with 10 mm length and 1.8 mm diameter), in cases where a guide hole is required, the increase in ratio is equal to 2.7 times inside and around the new biomechanism. The in vitro test validated the mathematical results, describing that in two different materials, the same compact factor of 3.45 was determined with the new biomechanical device. It was possible to describe that BKS can become a powerful tool in the diagnosis and treatment of natural bone conditions and any type of disease.
Biotribology is applied to study the friction, wear, and lubrication of biological systems or natural phenomena under relative motion in the human body. It is a multidisciplinary field and tribological processes impact all aspects of our daily life. Tribological processes may occur after the implantation of an artificial device in the human body with a wide variety of sliding and frictional interfaces. Blood is a natural bio-lubricant experiencing laminar flow at the lower screw velocities associated with drilling implants into bone, being a viscoelastic fluid with viscous and fluid characteristics. The viscosity comes from the blood plasma, while the elastic properties are from the deformation of red blood cells. In this study, drilling parameters according to material properties obtained by Finite Element Analysis are given. The influence of blood on the resulting friction between the surfaces is demonstrated and correlated with mechanical and biological consequences, identifying an innovative approach to obtaining a new lubricant parameter for bone drilling analysis. The lubrication parameter (HN) found within the limitations of conditions used in this study is 10.7 × 10−7 for both cortical bone (D1) and spongy bone (D4). A thermal-structural analysis of the densities of the soft bone (D4) and hard bone (D1) shows differences in only the equivalent stress values due to the differences in respective Young moduli. The natural occurrences of blood as a lubricant in bone-screw perforations are poorly investigated in the literature and its effects are fundamental in osseointegration. This work aims to elucidate the relevance of the study of blood as a lubricant in drilling and screwing implants into bone at lower speeds.
Oral maxillofacial rehabilitation of the atrophic maxilla with or without pneumatization of the maxillary sinuses routinely presents limited bone availability. This indicates the need for vertical and horizontal bone augmentation. The standard and most used technique is maxillary sinus augmentation using distinct techniques. These techniques may or may not rupture the sinus membrane. Rupture of the sinus membrane increases the risk of acute or chronic contamination of the graft, implant, and maxillary sinus. The surgical procedure for maxillary sinus autograft involves two stages: removal of the autograft and preparation of the bone site for the graft. A third stage is often added to place the osseointegrated implants. This is because it was not possible to do this at the same time as the graft surgery. A new bioactive kinetic screw (BKS) bone implant model is presented that simplifies and effectively performs autogenous grafting, sinus augmentation, and implant fixation in a single step. In the absence of a minimum vertical bone height of 4 mm in the region to be implanted, an additional surgical procedure is performed to harvest bone from the retro-molar trigone region of the mandible to provide additional bone. The feasibility and simplicity of the proposed technique were demonstrated in experimental studies in synthetic maxillary bone and sinus. A digital torque meter was used to measure MIT and MRT during implant insertion and removal. The amount of bone graft was determined by weighing the bone material collected by the new BKS implant. The technique proposed here demonstrated the benefits and limitations of the new BKS implant for maxillary sinus augmentation and installation of dental implants simultaneously.
The restoration of osseous defects is accomplished by bone grafts and bone substitutes, which are also called biomaterials. Autogenous grafts, which are derived from the same individual, can retain the viability of cells, mainly the osteoblasts and osteoprogenitor stem cells, and they do not lead to an immunologic response, which is known as the gold standard for bone grafts. There are both different techniques and devices that can be used to obtain bone grafts according to the needs of the patients, the location, and the size of the bone defect. Here, an innovative technique is presented in which the patient’s own bone is removed from the trigone retromolar region of the mandible and is inserted into a dental alveolus after the extraction and immediate insertion of an innovative dental implant, the BKS. The first step of the technique creates the surgical alveolus; the second step perforates the BKS in the retromolar region, and shortly after, the BKS containing the bone to be grafted is removed; the third step screws the BKS bone that collects in the created surgical alveolus. Experimental studies have shown the feasibility and practicality of this new technique and the new dental implant model for autogenous transplants.