Apatite-forming ability (bioactivity) of ProRoot MTA.
OBJECTIVE
Apatite-forming ability, considered as an index of bioactivity (bond-to-bone ability), was tested on ProRoot MTA cement after immersion in phosphate-containing solution (DPBS).


METHODS
Disk samples were prepared and immersed in DPBS for 10 min, 5 h, 1 and 7 days. The cement surface was studied by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, by micro-Raman spectroscopy and by environmental scanning electron microscope with energy dispersive X-ray (ESEM-EDX) analyses. The pH of the storage solution was also investigated.


RESULTS
Spectroscopic analyses revealed calcium phosphate bands after 5-h immersion in DPBS. After 1 day, an even coating composed of apatite spherulites (0.1-0.8 micron diameter) was observed by ESEM/EDX. After 7 days, its thickness had increased. Apatite nucleation had already occurred after 5-h immersion. At this time, the presence of portlandite (i.e. Ca(OH)(2) , calcium hydroxide) on the cement surface was also observed; at longer times, this component was released into the medium, which underwent a remarkable pH increase.


CONCLUSIONS
The study confirms the ability of ProRoot MTA to form a superficial layer of apatite within hours. The excellent bioactivity of ProRoot MTA might provide a significant clinical advantage over the traditional cements used for root-end or root-perforation repair.
Gandolfi
M G
MG
Laboratory of Biomaterials and Oral Pathology, Endodontic Clinical Section, Department of Odontostomatological Science, University of Bologna Department of Biochemistry, University of Bologna, Bologna, Italy. mgiovanna.gandolfi@unibo.it
Taddei
P
P
Tinti
A
A
Prati
C
C
D017607:Aluminum Compounds / Q000737:chemistry*; D001031:Apatites / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D002126:Calcium Hydroxide / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D055598:Chemical Phenomena; D004338:Drug Combinations; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007101:Immersion; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D015591:Microspectrophotometry; D010087:Oxides / Q000737:chemistry*; D010710:Phosphates / Q000737:chemistry; D012387:Root Canal Filling Materials / Q000737:chemistry*; D017640:Silicates / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013499:Surface Properties; D013997:Time Factors
D017607:Aluminum Compounds; D001031:Apatites; D001672:Biocompatible Materials; D017610:Calcium Compounds; D002130:Calcium Phosphates; D004338:Drug Combinations; D010087:Oxides; D010710:Phosphates; D012387:Root Canal Filling Materials; D017640:Silicates; C086631:mineral trioxide aggregate; C020243:calcium phosphate; D002126:Calcium Hydroxide