Effect Of Different Titanium And Porcelain On The Strength Of Pure Titanium Porcelain Crown

Objective: Choosing three manufacturers of pure titanium and twocommon brands of porcelain to make pure titanium porcelain crowns. Throughmechanics experiments to study the effect of different titanium and porcelainon the strength of pure titanium porcelain crown, expecting for a reference tothe selection and clinical application. It has certain guiding significance to theclinical application of PFM restorations at the same time.Methods：1Experimental dies preparation: A standard die which was simulatingthe crown core of first premolar was produced by precision instrument.Thisstandard die was supposed to meet the requirements of clinical preparation.The impression of the standard die was taken by silicon rubber. Then filledout36casting wax models. Though routine investment, nickel experimentaldies were casted. At last, the polishing of the dies was needed as well.2Porcelain crowns preparation: Used the silicon rubber again to makethe impressions of those experimental dies and filled out36plaster castmodels. After coating clearance paint and curing agent, the wax models of36titanium substrate crowns were fabricated. Divided those wax models into sixgroups randomly, and then chose three manufacturers of pure titanium to castthem into casting base crown, respectively. A multimetering by a standardcaliper was needed after polished to make sure the thicknesses of all the basemetal crowns were uniform, which were about0.3mm. After sandblasting andcleaning, the operation must be more strict,to prevent pollution the basecrowns. According to the different combinations of titanium and porcelain,chose Titankeramik or Duceratin Kiss to fuse on each group of the basalcrowns respectively: Group A(Titankeramik+TitaniumⅠ), Group B(Titankeramik+TitaniumⅡ), Group C (Titankeramik+Titanium Ⅲ), GroupD(Duceratin Kiss+TitaniumⅠ)、Group E(Duceratin Kiss+TitaniumⅡ),Group F(Duceratin Kiss+Titanium Ⅲ). The operation must strictly refer to the instruction book of each porcelain. Each basal crown should be fusedbond agent、twice opaque and dentine porcelain from the Titankeramik orDuceratin Kiss system and the thickness of each layer must strictly controlledby calipe. Then polished off the flash porcelain of each crown. The wholeoperation process must be done by a professional mechanic manufacture, inorder to reduce error.3Strength test and SEM observe: Used glass ion cement to adhesivethe PFM crowns from each group on the experimental dies. After24hours,when the cement is hardening completely, mechanical damage test began onthe universal load-testing machine. Record the data of fracture strength.Selected one PFM crown randomly from each group to prepare electronmicroscope samples and observed by scanning electron microscopy.Results:1Visual inspection showed that the porcelain layer stripped on thepalatal side more. No more residualed porcelain remained on the base surface,which prompted that the separation appeared between the oxide film and thesubstrate much more. Thin strips or dotted porcelain residual prompted thatthe separation appeared between the ceramic layers occasionally. Sheddingporcelain of the inner surface with a layer of uniform film, black surfaceoccasional white porcelain exposed. There was a layer of black uniform filmon the inner surface of the falled porcelain, and some white porcelainexposed occasionally.2Metal-ceramic surface under SEM: SEM observed that, thetitanium-porcelain surface of Group E, Group D and Group F which bombinedclosely was mutual crisscross, and the morphology compared relatively clear.No obvious crack or bubble. The continuous reaction thin layer at theinterfaces was a sign of better invasive between the titanium and porcelain.While the titanium-porcelain surface of Group A, Group B and Group C whichwas not closely bombined and could be seen cracks or bubbles occasionally,prompted less invasive between the titanium and porcelain.3The strength values of each group are as follows: Group A (1412.83 ±35.77) N, Group B (1380.50±37.51) N, Group C (1318.17±30.81) N,Group D (1489.33±47.44）N, Group E (1565.83±34.25) N, Group F(1430.50±37.15)N.The statistics analysis of the strength values of each group(P<0.05)showed that: compared Group A and group C, group D and group E, thedifferences were statistically significant; Group B compared with group C, D,E, there were significant differences; Group C compared with group E, F, therewere significant differences; Group D compared with group C, E, F,differences were statistically significant; Group E and group F compared,differences were statistically significant. Therefore we could concluded thatthe optimal combination of titanium and porcelain was group E (Duceratinporcelain powder and titaniumⅡ).Factorial analysis was used to determine the significant differences in thestrength values. The results showed that the choice of different pure titaniumfactors was P <0.01, that was, the choice of different pure titanium affectedthe strength of the porcelain crowns; The choice of different porcelaininfluenced the strength of the porcelain crowns; the interaction between twofactors suggested an interactive relationship between the two factors．Conclusions：1Different combinations of pure titanium and titanium porcelainpowder have certain influences on the strength of the pure titanium porcelaincrowns. Select the appropriate titanium and porcelain can improve the strengthof the porcelain crowns.2The strength of each combination in this experiment can meet theclinical needs. Among them, the combination of Duceratin porcelain powderand the pure titanium produced by luoyang MingTao technology co. LTD. canachieve the biggest strength.