HARDNESS AND PENETRATION OF GUTTA PERCHA WHEN EXPOSED TO TWO ENDODONTIC SOLVENTS EBRAHIM PATEL A research report submitted to the Faculty of Health Sciences, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Dentistry. Supervisor: Professor CP Owen School of Oral Health Sciences, Faculty of Health Sciences, University of the Witwatersrand, South Africa Johannesburg, 2014