Comparative study of cobalt-chromium and acetal resin direct retainers on abutment teeth in maxillofacial defects

Twelve patients with acquired maxillary defects were selected to participate in this study. They were divided into two equal groups. Patients of group I received definitive maxillary obturators constructed from cobalt-chromium frameworks; while those of group II received definitive maxillary obturators constructed from cobalt-chromium frameworks combined with acetal resin clasps. Bone height and density were measured at the time of denture insertion, six and twelve months later. After 6 months, there was no significant difference between the two groups in both bone density and bone height. However, after 12 months, there was significant difference between both groups where group I showed highly significant reduction in bone height and highly significant increase in the degree of blackening at P<0.01

Korner's septum; clinical, radiological and cadaveric studies

To describe the anatomy of the Korner's septum [KS] or petrosquamosal suture [PSS], its incidence, variations in normal and inflamed middle ears, and to evaluate its clinical importance. Review of 100 CT scans temporal bones were done to determine the degree of visualization of Korner's septum [KS]. Cadaveric dissection of 100 temporal bones were done in temporal bone dissection laboratory of Ain Shams University Specialzied hospital in addition to 100 mastoidectomies performed in the ENT inpatient department. KS or PSS is not only a bony plate dividing the mastoid cells at the level of the antrum, but is also a lamina starting from the posterior aspect of the glenoid fossa that extends above the middle ear cavity and courses inferiorly lateral to facial canal and proceeds to mastoid apex. Korner's septum was seen radiologically in 26% of CT scans of temporal bones, and in 25% of temporal bone specimens. Clinically "KS" was seen in [29%] of cases with COM and in [24%] in cases without COM with a total incidence of [28%]. Frequently there was a hidden cholesteatoma or cholesterol graunloma behind the septum. Rarely the cog [anterior part of the septum] may extend to fix the ossicels. KS is an imporatn anatomic observation in patients with chronic otitis media, it may contribute to middle ear infection and it may hide cholesteatoma or cholesterol granunloma behind it which may be missed if superficial compartment was sclerosed

Role of endoscopic control with canal wall down [CWD] in decreasing cholesteatoma recidivism

To evaluate the role of otoendoscope in conjunction with conventional otomicroscopic surgery of canal wall down technique; to inspect hidden areas and decrease rate of recidivism in cholesteatoma surgery. Also, to assess the role of partial obliteration of mastoid [leaving open attic] to decrease cavity problems of open technique. This study was conducted on 25 patients with cholesteatoma. Initial CWD technique was done for all cases in a trial to reduce recidivism. After complete removal of cholesteatoma matrix, otoendoscoy was used to inspect hidden areas, the incidence and sites of discovered cholesteatoma were recorded. Reconstruction of hearing mechanism and partial obliteration of mastoid were done. Follow up was done for 2 to 4 years and a C.T. scan was made after 1 to 2 years for every patient and a second look mastoidoscopy was carried out when needed. The incidence and site of recidivism was reported, and compared with the C.T. scan results. The use of otoendoscope after removal of cholesteatoma by otomicroscopic surgery lead to discover of residual cholesteatoma matrix in 9 patients [36%]. The highest incidence was in sinus tympani and facial recess and the least was in hypotympanum and round window niche. After partial obliteration of mastoid, cavity problems were encountered only in one patients [4%] and was successfully managed by local treatment. The second look mastoidoscopy revealed recidivism only in 1 patient [4%]. Otoendoscopy in cholesteatoma surgery improved visualization of hidden areas and decreased rate of recidivism. Also partial obliteration of lower mastoid in CWD technique lead to decrease complications of cavity problems

Management of a terminal questionable abutment in Kennedy class ii cases [a stress analysis study]

This stress analysis study, using strain gauges technology, was conducted to evaluate the conversion of a questionable terminal partial denture abutment tooth into an overdenture abutment sup-potting the distal extension base instead of its extraction. A simulating acrylic model of a mandibular class II Kennedy partially edentulous case was constructed, with the second premolar as the last standing tooth, this tooth was considered as a questionable abutment with grade II mobility. Four Strain gauges were installed on the buccal and mesial surfaces of the first premolar at the edentulous side and the first molar at the intact side. Another strain gauge was installed on a specially prepared flexible metal extension under the distal end of the denture saddle. Load were applied at two different preselected points on the denture saddle. Microstrains were recorded while the questionable tooth was used as an overdenture abutment and another time with the tooth removed. The results of this study demonstrated that preserving the questionable tooth and converting it into an overdenture abutment significantly reduces stresses on both the terminal abutment at the edentulous area and the first molar at the intact sidle as well as the distal area of the edentulous ridge