The Influence Of Different Coarsening Treatment To The Mechanical Strength Of Pure Titanium Implant

Objective:Since the last 60's century, oral dental implants are more and more accepted by people because of the aesthetic and comfortable properties, no harm to the adjacent teeth and good stability. So oral dental implants are called the third period of human teeth. Surface coarsening treatment can not only broaden the surface area, enhance biological activity of the surface, but also improve the osseointegration of pure titanium implant. Thus success rate of implanting is raised. After the coarsening treatment of chemical etching, high temperature treatment, sand blasting et al, the surface even the inside of pure titanium implant is influenced in different levels. Therefore, the coarsening treatment has influenced the mechanical strength of pure titanium implants. The study selects two-phase threaded cylindrical pure titanium implants as the object, takes sandblasted and acid etching as the method, uses SEM?scanning electron microscope?and EDXA?energy dispersive X-ray analysis?to observe and analysis the surface topography and surface element of pure titanium implants which are coarsened, uses universal testing machine to detect the fracture load to the implant. The objective is to discuss the influence of different coarsening treatment to the mechanical strength of pure titanium implant, to provide theoretical basis for the design of surface treatment of pure titanium implants.Method:1 Group of pure titanium implants and surface coarsening of pure titanium implantsSelect eighteen two-phase threaded cylindrical pure titanium implants, the mating abutments and abutment screws. These implants were divided into three groups, numbered A?B?C, there are six pure titanium implants each group. Ultrasonic clean the three groups of pure titanium implants 20 minutes using acetone?75%alcohol?distilled water respectively. Dry under the normal temperature.Group A?control group?: No surface coarsening processed.Group B?sandblasting and Ti O₂-normal temperature acid etching gr oup?:80 mesh number Ti O₂ sand, 0.2Mpa sandblasting air pressure; conc entrated HCl/H₂SO₄ etching 40 minutes under the normal temperature.Group C:?sandblasting and Ti O₂-60? acid etching group?: 80 mesh number Ti O₂ sand, 0.2Mpa sandblasting air pressure; concentrated HCl/H₂SO₄ etching 40 minutes under 60?.3 SEM and EDXA of surface topography of pure titanium plants after coarsening process.Using SEM to observe surface topography of Group A?B?C. Using EDXA to analysis surface element.4 Fracture testUsing universal testing machine to give lateral force to the three groups of specimens at the angle of 30°with respect to the implant axis until the whole specimens broken?loading speed=1mm/min?. Keep records of the load values of each group when the specimens turn to break.5 Statistical analysisStatistical analysis was conducted on the three groups of values of broken by SPSS 19.0 software. Test normality and homogeneity of variance. If the result was normal distribution, used mean and standard deviation to describe the results, and the results should be recorded in the form of X—±s. One Way-ANOVA and SNK-q test were chosen if the data were normally and the variances were the same. Ranking test was chosen if the data were not normally or the variances were not the same. Inspecting standard a=0.05.Rusults:1 SEM observations of surface topography of the three groupsGroup A: Smooth under the low power lens. In the same direction of shallow groove grain structures under high power lens, with dotted hollow occasionally.Group B: Slightly rough and no impurities under lower lens. Many cavities,hollows and fissures under high power lens with the diameter 10⁴0?m. No obvious second class cavities.Group C: Coarser under lower lens, no impurities in the groove and slope of the thread, dotted and stripe like hollows in the ridge of the thread. Many cavities with the diameter 10⁴0?m under high power lens. In these first class cavities, there are many irregular second class cavities with the diameter 1⁵?m.2 EDXA analyzing of the three groupsThe elements of the surfaces of Group A?B?C are all titanium element. The content is 100%.3 The results of fracture test of the three groupsGroup A: 596.25±21.42 N,the maximum value is 623.52 N,the minimum value is 570.19N; Group B:589.20±14.12 N, the maximum value is 609.01 N,the minimum value is 568.08N; Group C:557.17±17.91 N, the maximum value is 580.90 N, the minimum value is 537.95 N. There are significant difference of destruction test values on the three groups of pure titanium implants?P<0.05?. Multiple comparison results indicate that significant difference in destruction test values exist between group C and A, C and B?P<0.05?, no significant difference between group A and B?P>0.05?. The destruction modes of the three groups of implants are all bending deformation. The bending place is at the groove of the first thread to the implant root. There are microcracks at the grooves of each implants.Conclusions:1 The surface topography of implants which were conducted by sandblasting and Ti O₂-60? acid etching is greater than the surface topography of implants which were conducted by sandblasting and Ti O₂-normal temperature acid etching. Edge-blunted and distinct second class cavities come out. And there's no residual impurity elements on the surface.2 The implants under no surface coarsening treatment and the implants under sandblasting with Ti O₂-normal temperature acid etching have the higher mechanical strength than the implants under sandblasting with Ti O₂-60? acid etching. The mechanical strength of three group of implants are all higher than the maximum occlusal force. They can meet clinical application requirements.3 Although the mechanical strength of the implants which are conducted by the method of sandblasting and Ti O₂-60? acid etching decreases a little, the mechanical strength is still far higher than the maximum occlusal force. It is revealed that we can take sandblasting and Ti O₂-60? acid etching as the method of surface coarsening treatment to implants. In this way, the osseointegration is improved and the success rate of implanting is raised.