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Surface roughness and fatigue performance of commercially pure titanium and Ti-6Al-4V alloy after different polishing protocols.
J Prosthet Dent. 2005 Apr; 93(4):378-85.JP

Abstract

STATEMENT OF PROBLEM

Surface quality of cast metal is directly related to service performance under fatigue stress. Surface heterogeneities resulting from either finishing or polishing processes or by corrosive agents such as fluoridated solutions, can negatively affect fatigue life. Cast titanium frameworks are difficult to polish, and an accepted polishing protocol has not been established.

PURPOSE

This study evaluated and compared surface roughness of cast commercially pure titanium (CP Ti) and Ti-6Al-4V alloy submitted to conventional or electrolytic polishing, correlating the results with corrosion-fatigue strength testing performed in artificial fluoridated saliva. Specimens were also tested in air at room temperature to evaluate the effectiveness of the corrosion-fatigue test model.

MATERIAL AND METHODS

For each metal, 40 dumb-bell-shaped rods, 2.3 mm in diameter at the central segment, were cast. Conventional polishing was performed on 20 specimens of each metal following the manufacturer's instructions. A source of continuous electrical current was used for electrolytic polishing of the other 20 specimens of each metal, which were immersed in an electrolytic solution containing 5% fluoridric acid, 35% nitric acid, and 60% distilled water. Surface roughness, Ra (microm), was measured with a profilometer, and fatigue tests were carried out with a universal testing machine using a load 30% lower than the 0.2% offset yield strength. After failure, the fractured surfaces were examined using scanning electron microscopy. Surface roughness means were analyzed with a 2-way analysis of variance and the Tukey multiple comparisons test (alpha=.05).

RESULTS

Electrolytic polishing (0.24 +/- 0.05 microm) provided significantly (P <.05) lower surface roughness values than conventional polishing (0.32 +/- 0.06 microm). Regardless of the polishing protocol, surface roughness of Ti-6Al-4V alloy (0.25 +/- 0.06 microm) was significantly lower (P <.05) than that of CP Ti (0.31 +/- 0.05 microm), and the fluoridated environment did not influence fatigue performance. There was no correlation between fatigue performance and surface roughness.

CONCLUSION

Surface roughness of Ti-6Al-4V was significantly lower than that of CP Ti. For cast titanium frameworks, the electrolytic polishing regimen was found to be more effective than the manufacturer's polishing instructions with abrasives and rotary instruments. After polishing, differences in surface roughness values did not affect corrosion-fatigue performance.

Authors+Show Affiliations

Department of Prosthodontics, Federal University of Goias, UFG, College of Dentistry, Goiania, Brazil.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15798689

Citation

Guilherme, Aderico Santana, et al. "Surface Roughness and Fatigue Performance of Commercially Pure Titanium and Ti-6Al-4V Alloy After Different Polishing Protocols." The Journal of Prosthetic Dentistry, vol. 93, no. 4, 2005, pp. 378-85.
Guilherme AS, Henriques GE, Zavanelli RA, et al. Surface roughness and fatigue performance of commercially pure titanium and Ti-6Al-4V alloy after different polishing protocols. J Prosthet Dent. 2005;93(4):378-85.
Guilherme, A. S., Henriques, G. E., Zavanelli, R. A., & Mesquita, M. F. (2005). Surface roughness and fatigue performance of commercially pure titanium and Ti-6Al-4V alloy after different polishing protocols. The Journal of Prosthetic Dentistry, 93(4), 378-85.
Guilherme AS, et al. Surface Roughness and Fatigue Performance of Commercially Pure Titanium and Ti-6Al-4V Alloy After Different Polishing Protocols. J Prosthet Dent. 2005;93(4):378-85. PubMed PMID: 15798689.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Surface roughness and fatigue performance of commercially pure titanium and Ti-6Al-4V alloy after different polishing protocols. AU - Guilherme,Aderico Santana, AU - Henriques,Guilherme Elias Pessanha, AU - Zavanelli,Ricardo Alexandre, AU - Mesquita,Marcelo Ferraz, PY - 2005/3/31/pubmed PY - 2005/5/13/medline PY - 2005/3/31/entrez SP - 378 EP - 85 JF - The Journal of prosthetic dentistry JO - J Prosthet Dent VL - 93 IS - 4 N2 - STATEMENT OF PROBLEM: Surface quality of cast metal is directly related to service performance under fatigue stress. Surface heterogeneities resulting from either finishing or polishing processes or by corrosive agents such as fluoridated solutions, can negatively affect fatigue life. Cast titanium frameworks are difficult to polish, and an accepted polishing protocol has not been established. PURPOSE: This study evaluated and compared surface roughness of cast commercially pure titanium (CP Ti) and Ti-6Al-4V alloy submitted to conventional or electrolytic polishing, correlating the results with corrosion-fatigue strength testing performed in artificial fluoridated saliva. Specimens were also tested in air at room temperature to evaluate the effectiveness of the corrosion-fatigue test model. MATERIAL AND METHODS: For each metal, 40 dumb-bell-shaped rods, 2.3 mm in diameter at the central segment, were cast. Conventional polishing was performed on 20 specimens of each metal following the manufacturer's instructions. A source of continuous electrical current was used for electrolytic polishing of the other 20 specimens of each metal, which were immersed in an electrolytic solution containing 5% fluoridric acid, 35% nitric acid, and 60% distilled water. Surface roughness, Ra (microm), was measured with a profilometer, and fatigue tests were carried out with a universal testing machine using a load 30% lower than the 0.2% offset yield strength. After failure, the fractured surfaces were examined using scanning electron microscopy. Surface roughness means were analyzed with a 2-way analysis of variance and the Tukey multiple comparisons test (alpha=.05). RESULTS: Electrolytic polishing (0.24 +/- 0.05 microm) provided significantly (P <.05) lower surface roughness values than conventional polishing (0.32 +/- 0.06 microm). Regardless of the polishing protocol, surface roughness of Ti-6Al-4V alloy (0.25 +/- 0.06 microm) was significantly lower (P <.05) than that of CP Ti (0.31 +/- 0.05 microm), and the fluoridated environment did not influence fatigue performance. There was no correlation between fatigue performance and surface roughness. CONCLUSION: Surface roughness of Ti-6Al-4V was significantly lower than that of CP Ti. For cast titanium frameworks, the electrolytic polishing regimen was found to be more effective than the manufacturer's polishing instructions with abrasives and rotary instruments. After polishing, differences in surface roughness values did not affect corrosion-fatigue performance. SN - 0022-3913 UR - https://www.unboundmedicine.com/medline/citation/15798689/Surface_roughness_and_fatigue_performance_of_commercially_pure_titanium_and_Ti_6Al_4V_alloy_after_different_polishing_protocols_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022391305000521 DB - PRIME DP - Unbound Medicine ER -