Application of powder metallurgy sintering in the implantation of porous nickel-Titanium teeth

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Special properties of Nitinol alloys
1. Shape Memory refers to the deformation of martensite at the temperature below Mf after the parent phase of a certain shape is cooled from Af temperature to Mf temperature. After heating to Af temperature, the material will automatically recover its shape in the parent phase with the inverse phase transition.In fact, the shape memory effect is a thermally induced phase transition of nitinel alloy.

2. The so-called superelasticity refers to the phenomenon that a sample generates strains far beyond its elastic limit strain under the action of external forces and the strain can recover automatically when it is unloaded.In other words, in the parent phase state, the stress-induced Martensitic transformation occurs due to the effect of applied stress, thus the alloy shows different mechanical behaviors from ordinary materials, its elastic limit is far greater than that of ordinary materials, and it no longer follows Hooke’s law.Compared with shape memory properties, hyperelasticity has no thermal involvement.In a word, hyperelasticity means that the stress does not increase with the increase of strain in a certain deformation range. Hyperelasticity can be divided into linear hyperelasticity and nonlinear hyperelasticity.The stress and strain are nearly linear in the stress-strain curve of the former.Nonlinear hyperelasticity refers to the results of stress-induced Martensite transformation and its inverse phase transition during the loading and unloading process at a certain temperature range above Af. Therefore, nonlinear hyperelasticity is also called phase transition pseudo-elasticity.The pseudo-elasticity of Nitinol alloy can reach about 8%.The hyperelasticity of NiTi alloy can be changed with the change of heat treatment conditions. When the pantograph wire is heated above 400 ℃, the hyperelasticity begins to decrease.

3. Sensitivity of intra-oral temperature change: The orthodontic power of stainless steel wire and CoCr alloy tooth orthopedic wire is basically unaffected by intra-oral temperature.The orthodontic power of hyperelastic Nitinol tooth wire varies with the change of oral temperature.When the amount of deformation is constant.As the temperature rises, the orthodontic power increases.On the one hand, it can accelerate the movement of teeth, because the temperature change in the mouth will stimulate the blood flow in the stagnant area of blood flow caused by the capillary stagnation caused by the correction device, so as to make the repair cells get sufficient nutrition during the tooth movement, maintain their vitality and normal function.On the other hand, orthodontists cannot precisely control or measure orthodontics in the oral environment.

4. Corrosion resistance: Studies have shown that the corrosion resistance of niti wire is similar to that of stainless steel wire

5. Anti-toxicity: The special chemical composition of nickel-titanium shape memory alloy, namely, it is a nickel-titanium and other atomic alloy, containing about 50% nickel, which is known to have carcinogenic and cancer-promoting effects.In general, titanium oxidation of the surface layer ACTS as a barrier, making ni-TI alloys have good biocompatibility.TiXOy and TixNiOy of the surface layer could inhibit Ni release.

6. Gentle correction: The dental orthopaedic wire currently in commercial use includes austenitic stainless steel wire, cobalt-Chrome-nickel wire, nickel-chromium wire, Australian wire, gold wire and Stitanium wire.The load-displacement curves of these orthodontic wires under tensile test and three point bending test conditions.Nitinol unloading curve platform is the lowest and the flatest, indicating that it can provide the most durable and gentle corrective power.

7. Good shock absorption: The greater the vibration caused by chewing and night molars to the arch wire, the greater the damage to the root and periodontal tissue.Through different attenuation experiment results, the study found the arch wire stainless steel wire vibration amplitude is larger than hyperelastic nickel titanium silk, super elastic nickel-titanium arch wire the initial vibration amplitude is only half of stainless steel wire, good vibration and shock absorption characteristics of the arch wire is important for the health of the teeth, and traditional arch wire such as stainless steel wire, tend to increase the root absorption.

Introduction to Dental Tools

Dental caries, periodontal disease and disordered dentition are the three most common dental diseases at present. The swelling, pain and tooth defect caused by dental arch | will cause great troubles to people’s life.In addition, with the aging of the population in China, the demand for dental materials has increased greatly.Therefore, the research and development of dental materials need to be paid attention to.As early as 300 BC, people have been using metal materials for tooth loss.Dental metal materials mainly include stainless steel, CO-CR alloy, N1-TI alloy, precious metal alloy and so on.Because stainless steel, co-CR alloy, N1-TI alloy generally contain N1, Cr and other toxic elements, long-term application will cause allergic or toxic reaction, so it will be gradually replaced.The high price of precious metal alloy is not conducive to its wide application.Compared with these materials, titanium materials have advantages such as high specific strength, low elastic modulus, good corrosion resistance and biocompatibility, etc., so it has gradually been widely concerned and studied.

Application of Nitinol in dental industry

Dental caries, periodontal disease and disordered dentition are the three most common dental diseases at present. The swelling, pain and tooth defect caused by dental arch | will cause great troubles to people’s life.In addition, with the aging of the population in China, the demand for dental materials has increased greatly.Therefore, the research and development of dental materials need to be paid attention to.As early as 300 BC, people have been using metal materials for tooth loss.Dental metal materials mainly include stainless steel, CO-CR alloy, N1-TI alloy, precious metal alloy and so on.Because stainless steel, co-CR alloy, N1-TI alloy generally contain N1, Cr and other toxic elements, long-term application will cause allergic or toxic reaction, so it will be gradually replaced.The high price of precious metal alloy is not conducive to its wide application.Compared with these materials, titanium materials have advantages such as high specific strength, low elastic modulus, good corrosion resistance and biocompatibility, etc., so it has gradually been widely concerned and studied.

Porous nickel-iron table alloys need to be sintered in high vacuum degreasing furnace equipment with a high vacuum of 10-6mbar, and the vacuum at a position of 10-5mbar should remain unchanged.The whole process needs to be degreased first at about 400℃.

The sintering of titanium alloy requires a certain amount of nitrogen or argon to maintain the atmosphere.The highest sintering temperature needs to reach about 1250℃, which will be adjusted according to the process difference.
SIMUWU vacuum degreasing sintering furnace is the core.

SIMUWU RVS-D series high vacuum sintering furnace can be used for sintering. It can be protected by nitrogen-filled atmosphere. The heating chamber is made of molybdenum, so the sintered products are cleaner.
SIMUWU vacuum furnace equipment stable operation, reliable quality.Fully automatic intelligent control.We can customize the equipment according to different technology.

The following device parameters are for your choice:

Vacuum Debinding&Sintering Furnace
Models	Effective Working Dimension (mm)	Max Temp. (℃)	Ultimate Pressure (Pa)	Pressure Rising Rate (Pa/h)	Temp. Uniformity (℃)	Gas Type	Loading Capacity (kg)
RVS-226-D	200x200x600	1350	6.7*10–3	0.67	±5	N2/Ar	60
RVS-335-D	300x300x500	1350	6.7*10–3	0.67	±5	N2/Ar	100
RVS-4411-D	400*400*1100	1350	6.7*10–3	0.67	±5	N2/Ar	200
RVS-557-D	500*500*700	1350	6.7*10–3	0.67	±5	N2/Ar	300
RVS-669-D	600*600*900	1350	6.7*10–3	0.67	±5	N2/Ar	500
RVS-7710-D	700*700*1000	1350	6.7*10–3	0.67	±5	N2/Ar	700
RVS-8812-D	800*800*1200	1350	6.7*10–3	0.67	±5	N2/Ar	1000
RVS-9915-D	900*900*1500	1350	6.7*10–3	0.67	±5	N2/Ar	1200
Remark: The working zone of equipment could be customized base on customer’s production. The data based on empty, cold furnace.

Edited by: Lucky Hu;
Copyright: SIMUWU Vacuum Furnace

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