ABSTRACT:Purpose: The aim of this presentation is to summarize the clinical applications of BioHPP (High Performance Polymer) for removable and fixed restorations.Materials and methods: A critical survey was conducted among 299 literature sources related to PEEKs and in particular with BioHPP.Results and discussion: According to the literature in this field the mechanical properties (in particular its elasticity) of BioHPP are closer to those of the dental tissues, and this fact gives an advantage of this material compared to the metal alloys and the ceramics. A variety of procedures have been suggested to condition the surface of BioHPP in order to facilitate its bonding with resin composite cements. In the Prosthetic Dentistry BioHPP is widely used for fixed and removable restorations frameworks fabrication by pressing and by CAD/CAM technology.Conclusion: Nowadays investigations for new abilities of BioHPP use in Prosthodontics are conducted. They are based on combined alternative fixed restorations made of PEEKs and metal alloys.

The aim of the current paper is to review the available literature reporting on comparative studies of heat-cured resins and three-dimensionally printed biomaterials for denture bases in terms of their composition, properties, fabrication techniques and clinical performance. The methodology included applying a search strategy, defining inclusion and exclusion criteria, selecting studies to summarize the results. Searches of PubMed, Scopus, and Embase databases were performed independently by three reviewers to gather literature published between 2018 and 2021. A total of 135 titles were obtained from the electronic databases, and the application of exclusion criteria resulted in the identification of 42 articles pertaining to conventional and 3D printed technology for removable dentures. The main disadvantages of the heat-cured resins for removable dentures are that they require lots of special equipment, skilled personnel and time. Emerging technologies, such as 3D printed dentures, have the potential to alleviate these problems allowing for faster patient rehabilitation. With the development of digital dentistry, it is becoming increasingly necessary to use 3D printed resin materials for the manufacturing of removable dentures. However, further research is required on the existing and developing materials to allow for advancement and increase its application in removable prosthodontics.

Background: Gingivectomy is a procedure often performed in everyday clinical practice using numerous instruments. Aim: To evaluate and compare the gingival cut surface after gingivectomy with 6 different surgical instruments – a surgical scalpel, an Er:YAG laser, a CO2 laser, a ceramic bur, an electrocautery device, and a diode laser. Materials and methods: Gingivectomy using the above listed instruments was performed in 18 patients. The histological samples excised with a surgical scalpel were assigned as a control group and the other five types – as test groups. The following histological parameters were measured: coagulation layer thickness (in μm); presence or absence of a microscopic rupture and presence or absence of hemostasis in-depth. Results: The best instrument of the above listed ones which demonstrated excellent results is the CO2 laser. The Er:YAG laser has a thin coagulation layer and lack of hemostasis in-depth. The diode laser has the widest coagulation layer which is an advantage from a clinical point of view. Electrocautery proved to be as effective as the diode laser, but it should not be used around metal restorations. The ceramic bur has less pronounced hemostasis in-depth. Conclusions: Modern dentistry uses a wide variety of methods that are designed to be applied in everyday practice. Good knowledge of the ways to use them, their advantages and disadvantages is essential to obtaining the optimal result depending on the clinical case.

The aim of this paper is to review the available literature on the different methods for color stability determination of CAD/CAM milled and 3D printed resins for denture bases. The methodology included applying a search strategy, defining inclusion and exclusion criteria and selecting studies to summarize the results. Searches of PubMed, Scopus, and Embase databases were performed independently by three reviewers to gather the literature published between 1998 and 2022. A total of 186 titles were obtained from the electronic database, and the application of exclusion criteria resulted in the identification of 66 articles pertaining to the different methods for color stability determination of CAD/CAM acrylic resins for denture bases. Color change in dental materials is clinically very important for the dental operator, as it determines the clinical serviceability of the material. Discoloration of the denture bases can be evaluated with various instruments and methods. Dental resins may undergo color changes over time due to intrinsic and/or extrinsic factors. The extrinsic factors are considered the more frequent causes of color changes. According to a number of studies, CAD/CAM fabricated acrylics have achieved better color stability than the conventional PMMA (polymethyl methacrylate) resins.

This study investigated the colour stability of three dimensional (3D)-printed and conventional denture teeth after immersion in different colourants. A total of 60 artificial maxillary central incisors were selected from three types of materials: 3D-printed dental resin (NextDent, 3D Systems, Soesterberg, The Netherlands), prefabricated acrylic teeth in Ivostar Shade (Ivoclar Vivadent, Schaan, Liechtenstein), and SpofaDent Plus in shade A2 (SpofaDental, Jičín, Czechia). These were immersed in four types of colourants at room temperature (23 °C ± 1 °C), including artificial saliva (pH = 6.8) as a control group, coffee, red wine, and Coca-Cola (n = 5). The temperature and the pH of the colouring agents were maintained throughout all immersion periods. After 7 days (T1), 14 days (T2), and 21 days (T3), the ∆E values were measured with a SpectroShade Micro (SpectroShade, Oxnard, CA, USA) spectrophotometer. Their means were then calculated and compared by two-way ANOVA. The independent factors, immersion time and different staining solutions, as well as the interaction between these factors, significantly influenced ΔE. The highest and the lowest mean ∆Es were recorded for prefabricated teeth in red wine, and 3D-printed teeth in artificial saliva, respectively. All the specimens demonstrated an increased colour change at T1 compared to T3, and the difference in mean ∆E was statistically significant.

The aim of the current article is to analyze and compare post-retraction gingival height changes resulting from six different types of gingival-displacement methods, encompassing both conventional and surgical approaches. The study involved a comparative analysis of 263 teeth (consisting of 128 front teeth, 69 premolars, and 66 molars) from 23 patients. For the investigation, three classic retraction methods were utilized, namely the single-cord technique, retraction paste Expasyl, and retraction paste Astringent. Additionally, three surgical techniques were employed, which included ceramic bur rotary curettage, Er:YAG laser troughing, and diode laser troughing. A randomized split-mouth design was implemented, and a significance level of 0.05 was used for the study. The recovery of the free gingival margin height was assessed on gypsum models that were scanned using an intraoral scanner during the first and second week after the retraction procedure. The results revealed that all retraction methods, except for ceramic bur rotary curettage, led to clinically insignificant levels of gingival recession. The article provides insights into the effectiveness and safety of various gingival-displacement techniques, highlighting that most methods tested in the study resulted in minimal or negligible gingival recession post-retraction.

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Three-dimensional printed denture base resins are relatively new materials, and their properties need to be thoroughly investigated to assess whether they can be used clinically. The aim of the current study was to evaluate the colour stability of 3D printed and conventional denture base resins after immersion in different staining solutions. A total of 200 specimens were manufactured from two types of materials: 3D printed dental resin NextDent Denture 3D+ (NextDent, 3D Systems, the Netherlands) and heat-polymerized PMMA Vertex (3D Systems, the Netherlands), which were immersed in four types of colourants—artificial saliva, coffee, red wine and coke (n = 25). For measuring the colour changes (CIE-L*a*b* system), a SpectroShade Micro spectrophotometer (SpectroShade, Oxnard, CA, USA) was used. After seven days (T1), 14 days (T2) and 21 days (T3), the mean ∆E values were calculated and compared by the Bonferonni post hoc test. The data were processed using the statistical software SPSS 26. The level of significance for rejecting the null hypothesis was fixed at p < 0.05. The highest mean values for ∆E were found for both types of dental resin in red wine, and the lowest mean values for ∆E were found for 3D printed specimens in artificial saliva. The 3D printed denture base resin demonstrated better colour stability than the conventional acrylic materials. The staining effect correlated with the immersion time, with the red wine and coke having the strongest chromogenic impact and the period with the highest colour changes being 21 days.