The Application of Zirconia in Tooth Defects

Dental caries is among the most prevalent chronic diseases of childhood, affecting larger part of children and adults. Non-treated enamel caries can lead to destruction and then spreads into the underlying softer and sensitive dentine layer. Dental restorative materials are applied to treat and reconstruct damaged teeth clinically and recover their functions. Currently, there are various dental restorative materials available, and many appropriate materials are used to restore dental carious teeth. The applicability of biomimetic principles can elicit innovations in restorative dentistry for tooth conservation and preservation. There are three types of materials commonly used in dental restorations: resin, alloys, and ceramic. During the past decade, zirconia-based ceramics have been successfully introduced into the clinic due to acceptable biocompatibility, lower price compared with gold restorations, and better appearance than traditional metal-ceramic restorations. Recently, zirconia restoration is an acceptable treatment option in restorative dentistry and a developing trend in esthetic dentistry.

Evaluation of Knowledge and Practice of Yazd General Practitioners about Shade Selection of Fixed Dental Prosthesis in 2019

Introduction: The color matching of dental restorations is effective in the beauty of the smile and a dentist should be familiar with the subject of color and light to make a beautiful and natural prosthesis. The aim of this study was to investigate the knowledge and practice of general dentists in Yazd City about the choice of fixed prosthesis color in 2019. Methods: This was a descriptive-analytical cross-sectional study in which all the general dentists in Yazd City were included in the study by census. Data were collected in the field through a valid and reliable questionnaire containing 11 knowledge questions and 17 performance questions. Data were analyzed by SPSS software version 24 using t-test and ANOVA (α <0.05). Results: 150 dentists with a mean age of 39.14 ± 7.96 were studied in this study. The mean score of knowledge was 26.5 ± 3.32 out of 33 points. Mean knowledge score was not statistically significant with age, sex and dental work experience (P >0.05), but was associated with participation in retraining courses (P = 0.046). 79% of participants used brossage and prophylaxis before choosing a color, 31% used sunlight to choose a color, and 37% used the color of adjacent teeth as a color choice. Conclusion: The knowledge of general dentists in Yazd City in choosing the color of fixed prostheses was at a good level and the performance was relatively good. Participation in retraining courses had led to an increase in dentists' awareness in this field.

Comparison of Bond Strength in the Different Class of Resin Cements to Cast and CAD/CAM Co-Cr Alloys

Objectives. Despite the widespread use of resin cements in cementing dental restorations, their bond strength to CAD/CAM base metal alloys is not widely studied. This study aimed to evaluate the microshear bond strength (μSBS) between cobalt-chrome (Co-Cr) alloys fabricated using casting or CAD/CAM methods with three types of resin cements. Materials and Methods. Fifty Co-Cr blocks were prepared with CAD/CAM or casting technique. Specimens were divided using primer or not and bonded to three types of resin cements: Panavia F2, RelyX Unicem, and Duo-Link. The differences between the mean μSBS values were analyzed using the two-way ANOVA test and Tukey analysis (α = 0.05). The mode of failure was evaluated using a stereomicroscope. In addition, the specimens were examined by scanning electron microscopy (SEM) based on two received signals: backscattered electrons (SEB) and secondary electrons (SEs). One intact alloy specimen in each group was analyzed by energy-dispersive X-ray spectroscopy (EDX). Results. Most of the specimens in the no-primer group were prematurely debonded. Statistical analyses showed that the interaction between the alloy substrate and cement type was significant ( p = 0.001 ). The bond strength of Panavia F2 was significantly higher than Duo-Link in the CAD/CAM group ( p = 0.001 ). SEM evaluation confirmed the difference in grain structures, while EDX showed no remarkable difference in the chemical composition of the alloy substrates. Conclusion. Alloy fabrication technique may influence the bond strength of resin cements. In the CAD/CAM group, cement containing MDP molecules exhibited higher strength than the etch-and-rinse one.

Esthetic-functional reconstruction of posterior teeth with direct restorations (a case report)

Teeth restoration in respect with anatomy and function with direct composite restoration does not lose its relevance for many years. The driving factor for the widespread use of direct restorations is satisfactory aesthetic results, simplicity and high speed of their implementation, and relatively low cost. Moreover, dental restorations in direct technique are constantly being improved due to the unprecedented growth of technologies in the production of dental materials and equipment, which are now living their golden age. This article presents a clinical case of replacing old incompetent fillings with impaired marginal fit of the posterior teeth with highly aesthetic and functional composite restorations.

The impact of surfactants on nanosphere zinc phosphate synthesis

Recently, biomaterials have attracted widespread concern because of their compatibilities with live bodies. Among advanced biomaterials, zinc phosphate nanospheres particles are potential candidates for delivering drug and dental restorations. However, their fabrication methods are complicated and non-eco-friendly. In this study, we report the impact of surfactant supplements on the wet chemical preparation of zinc phosphate. Experimentally, Di-propylene glycol (DPG) and Trimethylolpropane (TMP) were added to the solution in the preparation step to compare the morphology of synthesized particles with the non-surfactant process. The morphology was examined by transmission electron microscopy. The addition of surfactants changed particle shape to spherical with a diameter of less than 200 nm. Moreover, the synthesized particles with DPG had a solid form, while those with TMP had a hollow structure (a diameter of 50-70 nm and shell thickness of 5-7 nm). Furthermore, X-ray diffraction, Fourier transforms infrared, and Thermogravimetric analyses analyzed properties of hollow particles.

Mechanical Properties of Polymer-Based Blanks for Machined Dental Restorations

The tremendous technological and dental material progress led to a progressive advancement of treatment technologies and materials in restorative dentistry and prosthodontics. In this approach, CAD/CAM restorations have proven to be valuable restorative dental materials in both provisional and definitive restoration, owing to multifarious design, improved and highly tunable mechanical, physical and morphological properties. Thus far, the dentistry market offers a wide range of CAD/CAM restorative dental materials with highly sophisticated design and proper characteristics for a particular clinical problem or multiple dentistry purposes. The main goal of this research study was to comparatively investigate the micro-mechanical properties of various CAD/CAM restorations, which are presented on the market and used in clinical dentistry. Among the investigated dental specimens, hybrid ceramic-based CAD/CAM presented the highest micro-mechanical properties, followed by CAD/CAM PMMA-graphene, while the lowest micro-mechanical features were registered for CAD/CAM multilayered PMMA.

Sculpting in Dentistry – Requirements, Methods and Limitations in Aesthetic Dentistry: A Minireview

The skill of sculpting is an interesting and important part of restorative and esthetic dentistry. This review article will help achieve an understanding on what we know about this art, the hurdles we have faced, advances achieved, the limitations we still face and would help to gain knowledge and information on how to further advance in the art of manipulation and sculpting of dental restorations. This article aimed to review available literature on manipulation techniques, to summarize the importance of sculpting and to identify methods to face the current limitations of the art.

Clinicopathological evaluation of focal reactive lesions of the Gingiva

Focal reactive gingival lesions are elicited by chronic irritation primarily due to dental plaque, calculus, overhanging dental restorations and ill-fitting dental prosthesis. Persistent irritation of the gingiva can lead to tissue injury and trigger inflammation leading to proliferation of endothelial cells, multi-nucleated giant cells, fibroblasts and tissue mineralisation. The aim and objectives of the study were to determine the relative frequency and distribution of focal reactive gingival lesions according to sex, age, and anatomical site in patients who presented at the Witwatersrand Oral Health Centre. Retrospective cross-sectional study Methods Convenience sampling of patient records from the years 2011 to 2017 were analysed from the Department of Oral Pathology and the Department of Oral Medicine and Periodontology at the Witwatersrand Oral Health Centre. Sociodemographic variables and clinical features were evaluated. Female patients accounted for 70.8% (n = 172) of all focal reactive gingival lesions, with the majority of the lesions having occurred in the maxilla (56.4%; n = 137). The age of patients ranged from 3 months to 88 years. Contrary to findings in other studies, the peripheral ossifying fibroma was the most common focal reactive gingival lesion, after analysing 243 cases