Stress distribution in the peri-implant area of pure titanium and titanium-zirconium small implants

Aim: In dental implant treatment, there is a demand for mechanically stronger implants. Despite the existence of several studies showing the clinical success of narrow diameter implants, most of them are based on pure titanium (cpTi) alloys. There is a few clinical evidences of the success rate of titanium-zirconium (TiZr) narrow diameter implants. The aim of this study was to evaluate the stress distribution in the peri-implant area of narrow diameter cpTi and TiZr implants under axial and oblique loads. Methods: Photoelastic models were produced using epoxy resin (PL2, Vishay Precision Group) from a master model. The implants (cpTi and TiZr; Straumann AG) had 3.3 mm in diameter and 12 mm in height. Loads of 100 N and 200 N were applied to the abutment at angles of 0° (axial), 10°, 20°, and 30° (oblique). A circular polariscope (Eikonal) was used under dark field white-light configuration. The isochromatic fringes were analyzed in the peri-implant region in 5 areas, using ASTM table with isochromatic fringes; cervical-mesial, cervical-distal, mid-mesial, mid-distal and apical. Results: In general, under axial and oblique loads, the stress in the TiZr implant was lower than in the cpTi implant. The load of 200 N produced the highest stress values in cpTi and TiZr implants. In both implants and loads, the fringes were located more in apical area at all angles evaluated. Conclusion: It can be concluded that for small implants, the load inclination and intensity change the pattern of stress distribution and the cpTi implant exhibited the highest peri-implant stress.

Unicondylar Tibiofemoral Arthroplasty – Opinions of the Members of the German Knee Society (DKG) and the German Professional Association of Orthopaedic and Trauma Specialists (BVOU)

Background The number of implanted unicondylar tibiofemoral knee arthroplasties (UKA) is despite the potential advantages in comparison to total knee arthroplasties (TKA) in Germany relatively low. Goal of this survey, initiated by the Small Implants Group of the German Knee Society, was to gather opinions and put them into context of the current literature. Methods Based on the Delphi method and the AWMF rules and standards, 19 statements were developed, which were presented to the members of the DKG and BVOU in an anonymous online survey using “SurveyMonkey”. Overall, 410 colleagues participated. Results The biggest detected controversies were the determination of indications with respect to the body mass index and the existence of a patellofemoral arthrosis. A general consent was determined that a contralateral tibiofemoral arthrosis grade III – IV and meniscal deficiency in the contralateral compartment are an absolute contraindication. There was a consent that age is not a limitation for the implantation of an UKA. If a personal minimum volume of 15 implantations/year should be implemented was seen controversial. Conclusion The personal opinion, eventually built by personal experiences, appears to be in conflict with the knowledge of scientific literature in many instances. Intensive training and education appears necessary.

A New Inertia-Based Linear Stepper Motor for Micro-Surgical Procedures

A new hand held surgical device intended to aid physicians in microsurgery is reported. This device provides a means for delivering small implants through the use of a precision motion linear stepper motor fabricated from silicon and piezoelectric components. The stepper motor described here utilizes the inertial properties of a moving mass as part of the actuation process. Micro Electromechanical Systems-based (MEMS) technology is used in building the device. Test instruments have delivered over fifty implants with consistent performance. Typically the test instruments have attained 1.2 mm/s advancement speeds against 3 Newton resistance loads, a maximum output force of 4.6 Newtons, and maximum total displacement of 38 mm.

Bioabsorbable polymers: Materials technology and surgical applications

Biostable and bioabsorbable biomaterials are used to manufacture implants for supporting, replacement, augmentation and guiding of growth of tissues. Bioabsorbable implants are a better choice for applications where only the temporary presence of the implant is needed. Because of bioabsorption of such implants, there is no need for a removal operation after healing of the tissue and the risks of implant related, long-term complications are eliminated or strongly reduced. Reinforcing of bioabsorbable materials is necessary in order to develop strong and safe, small implants for fixation of bone fractures and connective tissue damage. Self-reinforced bioabsorbable polymeric implants have been used so far extensively in the treatment of traumas of the musculoskeletal system.