study of tooth size in patients with supernumerary teeth using image analysis system

Supernumerary teeth [SNT] are those that are in excess of normal complement and mimic the normal shape. They are influenced by genetic and environmental factors and contribute to the variability of permanent tooth size

Objective: To investigate if the presence of supernumerary teeth has an effect on crown size of the dentition

Methods: The Supernumerary group consisted of 60 subjects [35 males and 25 females] and the control group of 40 subjects [20 males and 20 females]. All available permanent teeth on the dental casts were imaged and measured from both buccal and occlusal views using an image analysis system. Mesido-distal, bucco-lingual or occluso-gingival dimensions, area and perimeter were measured from each view

Results: Supernumerary tooth patients tended to have larger tooth size measurements for almost all variables than controls, significant difference [p<0.05] were found for most of tooth size dimensions with some evidence of a local effect with greater difference in tooth dimension adjacent to the site of the Supernumeraries

Conclusion: The results are compatible with SNT being a complex dental anomaly with multifactorial etiology in which both genetic and environmental factors are important

Clinical and radiographic study of two different designs for restoring unilateral mandibular distal extension bases

The present study was carried out to evaluate and compare two different designs for restoring unilateral mandibular distal extension [Kennedy class II]. Twenty patients were selected from the Proshtodontic out patient clinic Faculty of Dentistry, Tanta University. Their age ranged from 30-40 years. They had mandibular distal extension opposing natural teeth. All the patients were free from any systemic diseases that might influence the results. Also they had no previous prosthetic appliances. They were subjected to proper scalling, root planning and occlusal adjustment when necessary. The patients were randomly classified into two groups Group A: received RPD containing the distal saddle, Ceka extracoronal attachment, lingual bar and double Acker clasps. While Group B: received RPD containing the distal saddle, RPI clasp, cingulum rest on both canines, lingual bar and double Acker clasps. The following investigations were carried out; periodontal reaction of the abutments [Pocket depth, Gingival index and Probing attachment level], bone changes at abutments and residual alveolar ridge areas using Quantitative digital subtraction radiography and Gray scale levels. The results showed that the mean gingival scores in the Ceka group were higher than the RPI ones as regards the mean pocket depth and the mean attachment level. The mean alveolar bone loss in the Ceka group was high and statistically significant when compared to the RPI one. Based on the previous clinical and radiographical results, it could be concluded that:- The RPI clasp assembly causes less alveolar bone loss at the abutments compared to the Ceka assembly. The RPI clasp causes less resorption rates at the residual alveolar ridge when compared to the Ceka design. The RPI group showed less bone density changes when compared to the Ceka group. It can be concluded that the gingival indices may not be sufficient to reflect the changes of the whole periodontium. While the quantitative digital subtraction radiography enable the numerical statistical analysis between the study groups. Using the Gray scale level to trace the bone density changes is a sensitive alarming methodology pointing out to the sites of future bone loss before it occurs

validity of compact discs versus data show and light microscope slides in learning oral histology

The present research was conducted to evaluate the validity of a specially designed compact disc containing oral histology slide images with multiple choice questions for learning and self assisting purposes. A total of 100 oral histology slides were selected to be material of the present research. Sixty second year dental students were randomly selected form the Faculty of Dentistry, Tanta University to participate in the study. The students had practiced slide identification using the LM, data show slides and the compact discs for one week. The students were examined for slide identification through the LM, data show and the CD in three separate settings using a simplified chart containing the student name, slide number and the suggested answers. Student scores were collected, tabulated and statistically analyzed. The results showed significant improvement of the mean CD scores when compared to the mean data show and LM scores. It may be concluded that the interactive learning CD method is a helpful adjunct in learning oral histology

histochemical and radiographical investigation of bone formation process by topical versus systemic administration of alendronate in genia pig jaws with experimental periodontitis

Bisphosphonates are chemical analogues of systemic pyrophosphates. Alendronate [an aminobisphosphonate] is a useful agent to inhibit bone resorption without adverse effects on matrix mineralization. It is an effective drug for the treatment of osteoporosis, paget's disease and periodontitis. The present study was designed to compare the inhibitory effect of Alendronate on alveolar bone resorption when applied locally versus systemic route of application in Genia pig jaw with experimental periodontitis. Induce inflammatory experimental periodontitis was done in 30male Genia pig. A standardized periapical radigographs were tokes for upper maxillary central incisors before induction and at the end of experiment. The animals were classified equally into three groups. Group I [control group]: animals with experimental periodontits with no medication. Group II animals with periodontitis and given subcutaneous injection of Alendronate. Group III. Animals with experimental periodontitis and given subcutaneous injected Alendronate. At the end of experimental period [on day 8] the animals were sacrified and the segment of maxillary central incisors was dissected carefully and prepared for histochemical stains. Also, a specially developed visual basic module was developed to detect mean gray level in the interdental alveolar hone between the upper maxillary incisors. Our result revealed, the prevention of alveolar bone resorption, regeneration of epithelial attachment, reorganization of periodontal ligament and turn over of alveolar hone were cleary detected in both treated groups hut they were prominent in local treated group than systemic one. These histochemical results were supported by our radiographic results as statistically significant differences were found between three groups. In conclusion, the results of the present study, showed systemic and local Alendronate treatment inhibit the loss of alveolar bone in Genia pigs with experimental periodontitis. However in the light of this study for the clinical application of these compounds, localized use at a specific site without systemic effect would be desirable

Potential definition of the time of death from postmortem autolytic changes in human sweat glands

This study demonstrates postmortem autolytic alterations in the morphology of sweat glands at cellular and subcellular levels and identifies parameters which may contribute in determining the time of death. Serial skin samples were obtained from the ventral surface of the arms of 30 corpses at intervals of 3, 6, 9 and 12 hrs after death to be compared with seven antemortem normal skin samples that served as controls. Examination was carried out using light microscopy [for haematoxylin and eosin, PAS stained sections and toluidine blue stained semithin sections] and electron microscopy. Electron microscopy proved to be useful for identifying alterations which were found to be specific for each of the considered chronologic stage. Appearance of chromatin clumping, decrease in secretory granules and glycogen content were evident 3 hrs after death. Increased lipofuscin granules was observed 6 hrs after death. Changes in cell membrane appeared 9 hrs after death, while degenerative changes in the nuclei and nuclear membrane occurred 12 hrs after death

Computer-based methods for accurate bite mark analysis

The study was carried out on 24 adult male volunteers, who were asked to make experimental bite marks [each in his forearm]. Full arch rubber base impressions were taken for the upper and lower jaws and accurate mould of the bite mark lesion was obtained using light and heavy body rubber base impressing materials. Then casts were created by pouring the impressions with dental stone. The overlays were produced using computer-based method by direct scanning of the study casts, computer-based method by direct image capture using digital video camera, hand tracing of the casts, xerographic imaging of the casts and radiopaque wax impression method. Surface area and rotation of the biting edges of the anterior teeth corresponding bite mark lesions were measured and compared. The computer-based method was determined to be the most accurate representative of the biting edges of the teeth as evident from the highest correlation coefficient yielded between the biting teeth and the corresponding bite mark lesion regarding the surface area and rotation