Introduction: A post usually made of prefabricated or custom made that is fitted into a prepared root canal of a natural tooth. Core is the foundation restoration which restores adequate coronal anatomy of a vital or endodontically treated tooth. When the post is combined with a core, it provides retention and resistance for an artificial crown. The primary purpose of the post is to retain a core restoration and crown, and also to redistribute the stresses onto the root, thereby diminishes the risk of coronal fracture. The post does not have any role in reinforcing or supporting the tooth. The aim of the study was to assess the quality of the post and core restorations with postoperative periapical digital radiographs performed by undergraduate students at the College of Dentistry, Qassim University.Materials and methods: A total of 421 periapical digital radiographs were assessed. The assessment includes the type of tooth, type of arch, type of post, length of post, the presence of any abnormality in post space, status of the remaining gutta-percha (GP), and if there is any spaces between the end of post and GP. Data were analyzed using the Statistical Package for the Social Sciences (SPSS) program (version 23) .Results: Maxillary teeth were the most frequently restored teeth with post (67.2%) and majority of the cases were comprised of premolars (57.2%). Similarly, glass fiber post (89.1%) with taper shaped were the most widely used post. The majority of the post featured a width of one-third of the root (81%). Length of the post with crown: post ratio of 1:3 was observed as the most frequently used (60.8%), whereas those of post length with crown: post ratio of 1:2 (25.4 %) and 1:1 post length was least frequently used (13.8%). 28% of cases were presented with 3 to 5 mm of GP at their apical portion and 61.5% cases reached more than 5 mm. Approximately 5 to 8% of assessed cases revealed the widening of the periodontal ligaments.Conclusion: The performance of students was assessed by the quality of different types of post and core restorations with the postoperative periapical digital radiographs. The qualities of assessed post and core restorations prepared by the dental students were clinically acceptable.

Aim: The aim of this study was to evaluate the effect of concentration of chlorine on the polymethylmethacrylate and the influence of chemical properties of polymethylmethacrylate using ultraviolet-visible spectroscopy.Materials and methods: A total 30 acrylic blocks of dimensions 65X 13X 3 mm as per specification of ASTM [American standard for testing materials] were made in heat cure denture base resin to evaluate the effect of chlorine on polymethylmethacrylate. 30 samples were divided into 3 groups of 10 samples in each. Group I was stored in artificial saliva which acts as a control group, Group II was stored in 3ppm concentration of chlorine and Group III was stored in 100ppm concentration of chlorine.Results: Ultraviolet rays are passed into the sample, the results are obtained on a graph with wavelength in nanometer on X axis and the percentage of reflectance on Y axis. If an organic compound absorbs ultraviolet radiation, it means that the compound contains carbonyl or conjugated double bonds3. Since polymethylmethacrylate absorb ultraviolet rays, the existence on this bonds are confirmed in graph.Conclusion: Within the limitations of the study it was concluded that the effect of chlorine on polymethylmethacrylate can react over the conjugated bond or carbonyl group at higher concentration, whereas the action of chlorine is negligible at lower concentration.

Aim: The aim was to evaluate the physical properties of denture base resin in two different media such as artificial saliva and chlorinated water by using thermal gravimetric analysis (TGA) & differential thermal analysis (DTA). Materials and Methods: 40 samples divided into 2 groups of 20 samples each. One group was stored in artificial saliva the other group was stored in chlorinated water of 3ppm concentration. Total number of 40 acrylic blocks was grouped as Group I & II. Scrapings were taken from the blocks of both the Group I & II. Samples of artificial saliva and chlorinated water were subjected to thermal behavior by TGA and DTA. Results: TGA Thermograph of Group I shows broad endothermic peak at 282.90C to 357.70C and exothermic peak at 535.40C to 602.20C. TGA Thermograph of Group II shows broad endothermic peak at 336.20C to 362.20C and exothermic peak at 535.60C to 643.90C. The phase change corresponding to the weight change is shown in DTA thermograph. The thermograph of TGA/DTA shows changes in thermal behavior in both the medium. Conclusion: Changes in the physical properties of denture base resin such as transition temperature and phase changes were evaluated by thermal analysis. Chlorine being highly reactive will react with the double bonds of polymethylmethacrylate (PMMA). Blocking of double bond can affect the physical properties of denture base resin. Keywords: Polymethylmethacrylate, Differential thermal analysis, Thermal analysis, Denture base resin.

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Aim: Endosseous osseointegrated implants have enormously increased the potential for reconstruction of the patients with varied soft and hard tissue maxillofacial defects. This review focuses on the survival rate of endosseous implants in maxillofacial prosthesis. Background: In recent years, the endosseous implants for prosthetic rehabilitation of maxillofacial defects with acquired and congenital conditions have become more common practice with higher percentage of long-term success. Endosseous implants have been used for retention in the maxillofacial defects can offer excellent support and retention thereby eliminating the usage of adhesives. Review results: Maximum number of systematic reviews has been compiled by different authors on the success rate of endosseous implants. However, endosseous osseointegrated implants can remain in service for a long term, and many techniques are reliable and predictable. Conclusion: This article highlights the long-term outcomes of endosseous implants used to retain the various types of maxillofacial prosthesis. Keywords: Craniofacial defects, endosseous implants, maxillofacial prosthesis, osseointegration, maxillofacial defects.