الفهرس 
INTRODUCTION
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Abstract
Middle ear reconstructive techniques require the availability of biocompatible, reliable, economic, ready available reconstructive materials. The techniques should be technically simple, standard and versatile to adapt different reconstructive situations. The selection of the suitable reconstructive material is derived from a variety of physical, chemical, biomechanical, and surgical concepts.
The aim of the present study is to investigate relatively economic and ready available alloplastic reconstructive bio-materials that are Glass ionomer cement (GIC), mixture of Hydroxylapatite (HA) granules with GIC, and Telfon tubes as regards the tissue reactions when implanted in rats, the applicability in different middle ear reconstructive techniques, and the functional results after their clinical application.
The study was divided into two parts; the experimental part, that was conducted on 20 pathogen free female albino rats, and the applied part, that was conducted on 86 patients aging from 20 to 40 years who were diagnosed as chronic suppurative otitis media and were planned to undergo tympanoplasty ortympano-mastoidectomy for the first time.
In our experimental study, the three studied alloplastic reconstructive implants showed bigji biocompatibWity, TVO rejection reaction in amy animaV aftet 1 months of implantation sub-periosteally in the post-auricular region of rats. The results for the three materials were comparable to the control group in which Sham operation was done. The implants were well encapsulated by a fibrovascular layer. Evidence of new bone formation was found at the implant-bone interface in the glass ionomer cement and the mixture of hydroxypaptite and glass ionomer cement. The biocompatibility of the alloplastic materials were comparable to the studied tissue grafts, human cartilage and ossicles.
In the clinico-operative part of the study we applied the studied materials for ossiculoplasty and for bony wall reconstruction. For ossiculoplasty, we have chosen four commonly encountered ossicular defects in cases of chronic suppurative otitis media which are; eroded long process of incus, incus subluxation, absent or unusable incus and absent stapes suprastructure with mobile footplate of stapes. For bony wall reconstruction we applied the GIC+HA mixture cement in reconstructing scutal defects and in re-building the posterior canal wall. The follow-up period for all cases extended to at least one year after surgery.