The Effect of Blood Contamination on the Chemical Characterization of Hydrated Mineral Trioxide Aggregates and Their Dentin-Interface: A Comparative Study SAWSAN T. ABU ZEID 1,2 , LUBNA A. SHAFIE 1,2 , ABEER A. MOKEEM SALEH 1 , and MONAZAH G. KHAFAGI 3 1 Endododontic Department, Faculty of Dentistry, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia 2 Faculty of Oral and Dental Medicine, Cairo University, Cairo, Egypt 3 Spectroscopy Department, Physics Division, National Research Center, Giza, Egypt Received 1 May 2014, Accepted 31 May 2014 The presence of blood contamination could affect the chemical characterization of mineral trioxide aggregates as endodontic repair material during surgical approach. The aim of this study was to assess and compare the chemical characterization of two white mineral trioxide aggregates (ProRoot and Angelus) mixed with blood versus water. ProRoot and Angelus were mixed with either distilled water, fresh human blood, or diluted blood and analyzed using Fourier transform infrared spectroscopy. The same materials were packed inside holes in dentin blocks for scanning electron microscopy with energy-dispersive X-ray. Gray Portland cement was used as a control. The infrared spectra of unhydrate powders showed an increase in alite in ProRoot and Angelus, belite in Portland cement, and calcium hydroxide in Angelus. Upon hydration, changes in these bands were detected. Energy-dispersive X-ray dis- played significantly higher calcium, aluminum, and phosphorous in hydrated Angelus and silicon in hydrated ProRoot (p < 0.05). No phosphorous was detected in ProRoot. Traces of iron were detected in blood groups. A granular pattern was observed at the hydrated material of all tested groups. Definitive gaps were detected at certain areas within hydrated material and its dentin-interface, particularly in blood-contaminated groups. It was supported with the appearance of new bands assigned to Amide I and II of blood protein. It was concluded that the presence of blood during the hydration process of mineral trioxide aggregates produced small gaps of protein impurities within the hydrated material, affecting its chemical behavior and dentin=material-interface integrity. Keywords: mineral trioxide aggregates, blood contamination, chemical composition, infrared spectroscopy, scanning electron microscopy=energy dispersive X-ray, dentin-MTA interface Introduction Mineral trioxide aggregate (MTA) is a calcium silicate-based cement developed from Portland cement, [1,2] as a preferable material for endodontic repair. [3] ProRoot and Angelus are the two commercial products of MTA available in the market. MTA consists of fine hydrophilic particles that harden in wet environment. [2] In most of the clinical situa- tions, MTA set in the presence of blood compromises the properties of the material. [4] It was proved that the blood reduced its compressive strength, which resulted in lack of acicular crystals. [4] The chemical structure of MTA may also be affected by incorporated blood molecules. The aim of this study was to compare the effect of blood on the surface microstructure and chemical composition of white MTA (ProRoot and Angelus) versus ordinary gray Portland cement. Fourier transform infrared spectroscopy and scanning electron microscopy with energy-dispersive X-ray were used to identify both the organic and inorganic compounds of the tested materials. Materials and Methods White ProRoot-MTA (Dentsply DeTrey, GmbH, Konstanz, Germany), white MTA-Angelus (Londrina, PR, Brazil), and ordinary Portland cement (Italcementi SPA, Bergamo, Italy) were used (as control). According to the solution used, each material was mixed with distilled water, fresh natural con- centrated blood, or diluted human blood (powder:solution ratio of 3:1 by volume). From recently extracted human teeth, a total of 45 root dentin blocks of 8  8 mm and 2 mm depth, each having a rounded hole of 2 mm radius, were prepared. The holes in the dentin blocks were randomly filled with freshly mixed tested materials with either of the solutions (five dentin blocks in each subgroup). The speci- mens were covered with moist cotton pellets and incubated at 37  C with 100% humidity for one week until final setting. The work reported in this paper was presented at the 5th Confer- ence on Optical Spectroscopy, Lasers and Their Applications 24–27 March 2014, Cairo, Egypt. Address correspondence to Monazah Gamal El-Din Khafagi, Spectroscopy Department, Physics Division, National Research Center, Giza, Egypt. E-mail: Monazah_Khafagi@hotmail.com Spectroscopy Letters, 48: 631–637 Copyright # 2015 Taylor & Francis Group, LLC ISSN: 0038-7010 print/1532-2289 online DOI: 10.1080/00387010.2014.930915