Fibrous dysplasia is a bone disease known to man from time immemorial. It is a benign anomaly of bone development characterized by the replacement of normal bone by fibro-osseous tissue exhibiting varying degrees of osseous metaplasia (Batsakis 1979, Jackson et al 1982, Shafer et al 1983). The condition has been broadly defined as monostotic and polyostotic.

In contradistinction to fibrous dysplasia in general, it has been reported that in the cranio-orbital area the lesion is more osseous with bony trabeculae predominating (Jackson et al 1982). In craniofacial fibrous polyostotic dysplasia, signs and symptoms may be multiple and varied, including facial swelling, poor aesthetics, deafness, malocclusion, blindness. Proptosis and asymmetrical orbital dystopia may also occur. Cranial nerve palsies and visual problems are not uncommon.

A case of craniofacial polyostotic fibrous dysplasia is presented, which underwent resection of the lesion through the subtemporal, preauricular, infratemporal approach.
Saudi Dental Journal 1994;6(SI)-Abstr.101:p108

The human tongue is involved in such important functions as swallowing, speech, taste and cleansing of the oral cavity. It begins it's development as early as four weeks in utero and is reported to begin movement at 12.5 weeks. Several studies have been done to investigate the ultrastructural. histologic and morphologic characteristic of the dorsal tongue of different mammalian species. However, data on the development and histomorphology of human fetal tongue papillae are lacking. The objective of this investigation is to examine the developing papillae of 20 week fetal tongue. Specimens from the dorsal tongue were fixed in 10% neutral buffered formalin, photographed with a stereoscope and subsequently processed for light microscopy. Additional specimens were processed for Scanning Electron Microscopy (SEM).

Stereoscopic examination revealed numerous small blunt or conical projections presumably representing developing filiform papillae. In addition, large oval structures appeared to be the forerunners of fungiform papillae. SEM analysis showed topographic features reminiscent of periderm of fetal skin. Histologically, the filiform papillae comprised of 2-3 epithelial cell layers lacking keratohyalin granules referred previously by others in the adult human tongue papillae. These studies show that fetal tongue contained the biostructural element considered precursors of the adult papillae. However, the epithelial cells lacked specific organelles necessary for epithelial cell differentiation.
Saudi Dental Journal 1994;6(SI)-Abstr.102:p109

Cervical burnout (CB) or cervicolucency is an optical phenomenon seen in cervical margin of teeth in dental radiography. Its determination is important in the diagnosis, since it simulates proximal caries. The present study is based on the retrospective analysis of 25 full mouth intraoral radiographs (500 films) including bitewing radiographs of patients records attending the dental clinics of College of Dentistry, King Saud University.

The main objective of the study was to determine the frequency of CB. in different teeth in dental radiographs and its disappearance following change of angulation from periapical to bitewing. An attempt has also been made to classify the CB. hitherto not traceable in the literature. Analysis of data has revealed that the CB. is more frequent (69.3%) in the maxillary teeth as compared to the teeth in the mandible (30.7%). Upper central incisors had the highest (40.5%) incidence of CB. while the least was in the third molar (7.0%). In mandible, canine had the highest occurrence (24.4%) of CB. and the least (1.2%) was again in the third molars. While 76% of the CB. disappeared following change of angulation in upper and lower premolars, less than 50% of rest of the teeth showed disappearance of this phenomenon.
Saudi Dental Journal 1994;6(SI)-Abstr.103:p110

Endodontic irrigating solution or combination of solutions that produces a cleaner canal may result in better clinical success. The purpose of this study is to test the ability of six irrigating solutions, used singly to clean the primary incisors root canals as observed through the Scanning Electron Microscope (SEM). Twenty-four extracted primary incisors with at least 2/3 of the root intact were used. The preparation was done using the technique of Aktener et al (1993). To facilitate teeth fracture, two parallel, longitudinal grooves which did not penetrate the root canals were made on the external surface of the teeth. The sample was divided into 6 groups of four teeth. The teeth in the control group were irrigated with normal saline solution for 30 seconds. The specimens in the other groups were irrigated with 5.25% sodium hypochlorite (NaOcI) for 15 and 30 seconds, 6% citric acid for 15 and 30 seconds and 3% hydrogen peroxide (H₂0₂) for 30 seconds. The coronal and middle thirds of the canals were scanned and examined following fracture without knowledge of the experimental groups according to the rating system developed by Rome et al (1985).

The SEM evaluation of the canal walls showed that the smear layer was totally removed and the openings of the dentinal tubules were patent when using citric acid (15 or 30 seconds) and NaO.cl (30 seconds). Moderate smear layer was observed with NaOcI (15 seconds) and moderate or heavy smear layer with H₂0₂. The results of this study indicate that a single solution may be used to remove organic or inorganic components of the smear layer of primary incisor root canals.
Saudi Dental Journal 1994;6(SI)-Abstr.104:p111

An intimate molecular contact between the adhesive and substrate is necessary for adhesion to take place. Therefore, the use of dentin surface conditioners to remove the smear layer is needed prior to placement of glass ionomer restorative cements (GICs). The way the dentin surface conditioner is applied to dentin may affect adhesion of GIC.

It was the purpose of this investigation to evaluate and compare the effect of active and passive dentin surface conditioning on the adhesion of GICs.

Active and passive surface conditioner application using 25% poly (acrylic acid) and 25% tannic acid were employed. Flat occlusal dentin surfaces of 75 human molars were prepared and conditioned. 5 specimens of each of 3 brands of GICs were prepared against the flat dentin surfaces using each of 4 combinations of application - agent. The adhesion between dentin and GICs was determined in tension following thermal cycling.

Active and passive dentin conditioning with 25% tannic acid yielded no significant difference (P > 0.05) in increased tensile strength of adhesion to GICs with exception of Ketac-Fil which showed a marked significant increase with active dentin conditioning. Also, the data recorded for this study showed that active and passive dentin conditioning with 25% poly (acrylic acid) had no significant effect (P > 0.05) on tensile strength of adhesion to Ketac-Fil and Fuji II, while active conditioning significantly decreased the tensile strength of adhesion to Aqua lonofil GIC.
Saudi Dental Journal 1994;6(SI)-Abstr.105:p112

  Salwa E  Khier,
King Saud University College of Dentistry, P.O. Box 60169, Riyadh 11545, Kingdom of Saudi Arabia.

The construction of many dental appliances requires the use of waxes with specific and often markedly different physical properties. Dental waxes are usually a blend of natural and synthetic materials to develop those properties desired for a particular application.

In this project, the mechanical properties namely; elastic modulus, compressive strength and flow of some commercially available casting dental waxes were measured at various temperatures from 21 to 40°C. Also, it was intended to characterize the thermal behavior of these waxes and indicate their phase transitions. A possible correlation between the mechanical and thermal behavior of casting waxes was investigated.

Three commercially available casting dental waxes were investigated. The mechanical properties of wax specimens were determined at selected temperatures ± 0.5°C using a universal testing machine at crosshead speed of 0.02 in/min. A different scanning calorimetric (DSC) analysis was utilized to characterize the thermal behavior of tested waxes.

The results of this study showed, in general, that mechanical properties decreased with increasing temperatures. In addition, the data recorded from (DSC) analysis suggested a direct correlation between the phase changes, associated with different transition temperature, and the mechanical behavior of casting dental waxes.
Saudi Dental Journal 1994;6(SI)-Abstr.106:p113