The aim of the article is to present a narrative review of the literature related to the different shade guides available for dental practitioners.A literature search was performed in the online databases -PubMed, Science Direct, MedLine and GoogleScholar with the following keywords -shade guide, shade matching, dental, dentistry. Furthermore, a hand search, including "grey" literature and printed resources available to the authors, was conducted. More than 2100 unique articles, including the selected keywords, were identified. After a critical review and elimination process, 39 of the papers were included.Dental shade guides are a set of colour standards mimicking the colour of tissues, which dentists aim to restore -tooth structures, gingival tissues or facial structures in facial prosthodontics -skin, mucosa, eyes etc. They can be systematized based on the following principles -fabrication process, the material of manufacturing or restoration and according to the tissues, which are restored.The most commonly used shade guides in the dental practice are structured around Munsell's 3-dimensional colour system and are aimed at the restoration of tooth colour. The colour standards for gingival and facial restoration are not routinely utilized since they are aimed at specialists in prosthetic dentistry and facial prosthodontics and are underdeveloped to some degree in comparison with the aforementioned.The contemporary development in aesthetic restorative materials and procedures requires an adequate follow up in the evolution of shade guides since they present the only means of communication between the dental office and laboratory.

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Objective: To evaluate the change of diameter of different injection-molded thermoplastic materials. Material and Methods: Four thermoplastic injection-molded materials were analyzed (Bre.flex 2 nd edition, Vertex ThermoSens, Perflex Biosens and Polyan IC). A total of 432 test samples were made in the form of an "hourglass". All samples were divided into three groups: Group I (Control) -consisting of 36 test samples for each type of material, that was not exposed to artificial aging or a wet environment; Group II -consisting of 36 test samples for each type of material, that were artificially aged through dehydration; Group III -specimen were subjected to artificial aging without dehydration. The diameter of each specimen was measured with a digital caliper. Data were analysed using the Student's t-test. Results: Regarding to shrinkage, the samples from the Bf Control group have a mean value of 1.56 mm and was observed a shrinkage of the injection-molded polyamide material within 0.25%. The comparison between the samples from Group II and Group III showed statistically significant differences (p<0.001). There were no significant differences between groups for Thermosens and Biosens (p>0.05). The comparison between Group II and Group III for Polyan IC samples shows that Group III has a higher arithmetic mean value (p<0.01). Conclusion: Shrinkage of the polymers during the injection process is present in all materials. The thermocycling and the storage in a dry or in a wet environment of the samples results in a change of the diameter in almost every single type of material.

One of the main issues with complete dentures is their retention and stability while functioning. People would like to eat with their dentures on in a high-quality way, without having the feeling of the presence of a foreign body in their oral cavity. Another serious problem is the patients' discomfort when they are fitted with new complete dentures and the impeded adaptation to them. On the Bulgarian and world markets, there are a lot of products aimed at eliminating these problems. Some of them are denture adhesives, also called gules or denture fixatives. There is a widely spread opinion they help only in case the dentures are often disconnected and are poorly wrought, but both a large part of the patients and some dental, medical doctors are not well acquainted with the advantages and shortcomings of denture adhesives; the indications and contraindications to their application. In Bulgaria, the most widely adopted denture adhesives are Corega, Protefix, Dental, Oradey, etc.

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