Biomechanical determinants of the stability of dental implants: Influence of the bone–implant interface properties

The application of Ti-6Al-4V alloy or commercially pure titanium for additive manufacturing enables the fabrication of complex structural implants and patient-specific implant geometries. However, the difference in Young's modulus of α + β-phase Ti alloys compared to the human bone promotes stress-shielding effects in the implant-bone interphase. The aim of the present study is the mechanical characterization of a new pre-alloyed β-phase Ti-42Nb alloy for application in additive manufacturing. The present investigation focuses on the mechanical properties of SLM-printed Ti-42Nb alloy in tensile and compression tests. In addition, the raw Ti-42Nb powder, the microstructure of the specimens prior to and after compression tests, as well as the fracture occurring in tensile tests are characterized by means of the SEM/EDX analysis. The Ti-42Nb raw powder exhibits a dendrite-like Ti-structure, which is melted layer-by-layer into a microstructure with a very homogeneous distribution of Nb and Ti during the SLM process. Tensile tests display Young's modulus of 60.51 ± 3.92 GPa and an ultimate tensile strength of 683.17 ± 16.67 MPa, whereas, under a compressive load, a compressive strength of 1330.74 ± 53.45 MPa is observed. The combination of high mechanical strength and low elastic modulus makes Ti-42Nb an interesting material for orthopedic and dental implants. The spherical shape of the pre-alloyed material additionally allows for application in metal 3D printing, enabling the fabrication of patient-specific structural implants.

Mechanical Properties of a Newly Additive Manufactured Implant Material Based on Ti-42Nb.

Threaded implants have been shown to play an important role in increasing mechanical osseointegration The aim of this study was to determine bone stress distribution when using different types of implant thread pitches and designs Five 3D finite element models were constructed to simulate bone stresses induced in implant bodies with two types of thread form: triangular (“Tri” prefix) and trapezoidal (“Trap” prefix) The former had thread pitches of 08, 12, and 16 mm, while the latter had thread pitches of 12 and 16 mm A biting load of 143 N was applied vertically and obliquely to the occlusal central fossa of the crown The main effects of each level of the three factors investigated (loading type, pitch, and thread form) in terms of the stress value were computed for all models Results indicated that the loading type was the main factor of influence on the peak compressive stress of the alveolar bone Optimal thread pitch was 12 mm for a triangular-thread implant, and a trapezoidal-threaded implant with thread pitch of 16 mm had the lowest stress value among trapezoidal-threaded implants This study concluded that each thread form has its unique optimal thread pitch with regard to lower concentration of bone stress Clinically, this study suggests that in biomechanical consideration, thread pitch exceeding 08 mm is more appropriate for a screwed implant For clinical cases that require greater bone-implant interface, trapezoidal-threaded implants with thread pitch of 16 mm provide greater primary stability and lower concentration of bone stress under different loading directions

Biomechanical analysis of alveolar bone stress around implants with different thread designs and pitches in the mandibular molar area

Shu-Wei Wu

Papers

Effects of implant threads on the contact area and stress distribution of marginal bone

The effects of flute shape and thread profile on the insertion torque and primary stability of dental implants

Correlation of the experimental and numerical results for the holding power of dental, traumatic, and spinal screws.