Comparative Analysis of the Mechanical Properties and Biocompatibility between CAD/CAM and Conventional Polymers Applied in Prosthetic Dentistry

Modern media often portray CAD/CAM technology as widely utilized in the fabrication of dental prosthetics. This study presents a comparative analysis of the mechanical properties and biocompatibility of CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) polymers and conventional polymers commonly utilized in prosthetic dentistry. With the increasing adoption of CAD/CAM technology in dental laboratories and practices, understanding the differences in material properties is crucial for informed decision-making in prosthodontic treatment planning. Through a narrative review of the literature and empirical data, this study evaluates the mechanical strength, durability, esthetics, and biocompatibility of CAD/CAM polymers in comparison to traditional polymers. Furthermore, it examines the implications of these findings on the clinical outcomes and long-term success of prosthetic restorations. The results provide valuable insights into the advantages and limitations of CAD/CAM polymers, informing clinicians and researchers about their suitability for various dental prosthetic applications. This study underscores the considerable advantages of CAD/CAM polymers over conventional ones in terms of mechanical properties, biocompatibility, and esthetics for prosthetic dentistry. CAD/CAM technology offers improved mechanical strength and durability, potentially enhancing the long-term performance of dental prosthetics, while the biocompatibility of these polymers makes them suitable for a broad patient demographic, reducing the risk of adverse reactions. The practical implications of these findings for dental technicians and dentists are significant, as understanding these material differences enables tailored treatment planning to meet individual patient needs and preferences. Integration of CAD/CAM technology into dental practices can lead to more predictable outcomes and heightened patient satisfaction with prosthetic restorations.

A 3D-simulation study of the deformation, tension, and stress of 3D-printed and conventional denture base materials after immersion in artificial saliva

INTRODUCTION

The worldwide application of digital technology has presented dentistry with transformative opportunities. The concept of digital dentures, incorporating computer-aided design (CAD) and computer-aided manufacturing (CAM) techniques, holds the promise of improved precision, customization, and overall patient satisfaction. However, the shift from traditional dentures to their digital counterparts should not be taken lightly, as the intricate interplay between oral physiology, patient comfort, and long-term durability requires thorough examination.

Recent Advances in 3D Printing of Polymers for Application in Prosthodontics

Contemporary mass media frequently depict 3D printing as a technology with widespread utilization in the creation of dental prosthetics. This paper endeavors to provide an evidence-based assessment of the current scope of 3D printing's integration within dental laboratories and practices. Its primary objective is to offer a systematic evaluation of the existing applications of 3D-printing technology within the realm of dental prosthetic restorations. Furthermore, this article delves into potential prospects, while also critically examining the sustained relevance of conventional dental laboratory services and manufacturing procedures. The central focus of this article is to expound upon the extent to which 3D printing is presently harnessed for crafting dental prosthetic appliances. By presenting verifiable data and factual insights, this article aspires to elucidate the actual implementation of 3D printing in prosthetic dentistry and its seamless integration into dental practices. The aim of this narrative review is twofold: firstly, to provide an informed and unbiased evaluation of the role that 3D printing currently plays within dental laboratories and practices; and secondly, to instigate contemplation on the transformative potential of this technology, both in terms of its contemporary impact and its future implications, while maintaining a balanced consideration of traditional dental approaches.

A Comparative Analysis of Post-Retraction Changes in Gingival Height after Conventional and Surgical Gingival Displacement: Rotary Curettage, Diode and Er:YAG Laser Troughing

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.

COLOR CHANGES OF 3D PRINTED AND CONVENTIONAL DENTAL RESINS FOR REMOVABLE PROSTHODONTICS AFTER IMMERSION IN DIFFERENT STAINING AGENTS

Introduction: The discoloration of the denture base resins is one of the shortcomings of this type of dental materials, and it could be determined through various visual and instrumental methods. The aim of the current study was to evaluate the color stability of 3Dprinted and conventional denture base resins after immersion in different staining solutions. Materials and methods: A total of 200specimens 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 colorants - artificial saliva, coffee, red wine and coke (n = 25). For measuring the color changes (CIE-L*a*b* system) of all specimens after storage in artificial saliva for 24 h at 37 degrees C (T0), a spectrophotometer SpectroShade Micro (SpectroShade, USA) was used. After seven days (T1), 14 days (T2) and 21 days (T3), the mean ∆E values were calculated and compared by Bonferonni post-hoc test. The data were processed using thestatistical software SPSS 26. The level of significance forrejecting the null hypothesis was fixed at p<0,05. Results: The values for ΔE were investigated, and the interactions between the type of material,the immersion time and the different staining solutions were statistically significant. The highest mean for ∆E was evaluated for both types of dental resin in red wine. Respectively, 3D printed specimens in artificial saliva were with the lowest mean. Conclusions: The 3D printed denture base resin demonstrated better color stability than the conventional acrylic materials. The staining effect correlated with the immersion time, with the red wine and coke being with the most chromogenic impact and the period with the highest color changes being 21 days.There was a significant interaction between theselected time periods and the type of staining agent, as both types of dental materials showedchanges in color stability at T1 compared to T3.

Colour Stability of 3D-Printed and Prefabricated Denture Teeth after Immersion in Different Colouring Agents—An In Vitro Study

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.

Calcification of the Atlanto-Occipital Ligament (Ponticulus Posticus) in Orthodontic Patients: A Retrospective Study

Background: Ponticlus Posticus (PP) is a rare anomaly of the first cervical vertebra easily identifiable in lateral cephalometric radiograph and typically required for orthodontic diagnosis. The aim of this study is to evaluate the PP prevalence in lateral Cephalograms in a cohort of orthodontic patients treated at the Dental School of the University of Bari ‘Aldo Moro’, Italy, and to find possible connection between PP and other dental anomalies, as well as the patient’s cephalometric characteristics. Methods: A total of 150 panoramic radiographs and 150 lateral Cephalograms, obtained for orthodontic use only, were evaluated. No patients were referred to for congenital syndromes or disease, or a history of previously occurred maxillofacial trauma. A detailed cephalometric study was performed for each patient, and the whole cohort was divided according to the common three dental malocclusion classes. The values obtained were analyzed using the Chi-Square Test. Results: PP prevalence was 8% (12 of 150 cases), where the complete and partial forms observed 4.7% and 3.3%, respectively. Although females were more affected (9.6%), no statistically significant sex-related difference was found. Furthermore, no statistically significant relationship regarding age or dental anomalies (dental agenesis/palatal impacted canines) among the groups was observed either. Cephalometric analyses revealed that half of the subjects with PP were sagittal skeletal class I and had vertical hyper-divergence. Conclusions: PP is a frequent anatomical variation of the cervical vertebra, apparently unrelated to the skeletal malocclusion type or dental anomalies. The current study needs to further confirm the congenital hypothesis of PP’s origin already reported in literature.

Laser-Assisted Gingivectomy to Treat Gummy Smile

Excessive gingival display (EGD) is the extensive exposure of the gingiva during a smile. It is a common concern among patients, which may compromise the esthetic outcome of the dental treatment. Dental lasers demonstrate several advantages for soft tissue dental surgery compared with conventional surgical methods related to their technical characteristics. Owing to the excellent coagulation, especially of the surgical lasers, reduced to no need of anesthesia or suturing and faster healing, they demonstrate optimal clinical results. Nevertheless, good knowledge of laser-tissue interaction is required to obtain the best predictable results without gingival recession or bone tissue damage.

SURGICAL AND NON-SURGICAL LASER PREPROSTHETIC PERIODONTAL PREPARATION. LOW-LEVEL LASER THERAPY AND PHOTOACTIVATED DISINFECTION

Background: Clinical success and functional durability of indirect restorations depend on optimal dental health before the prosthetic treatment and the manipulation of the gingival tissues. The aim of the current article is to review the surgical and non-surgical laser methods that can be applied as periodontal preparation in fixed prosthodontics. Review results: Preprosthetic periodontal preparation includes conventional periodontal therapy (non-surgical) and periodontal resective (surgical) procedures - soft and hard tissue crown lengthening. The advantages of lasers in the latter are reduced bleeding, less postoperative discomfort and faster healing. Non-surgical preprosthetic preparation, on the other hand, aims at microorganisms’ level reduction. The variety of protocols, which reduce the microbial number significantly, show photoactivated disinfection as adjunctive therapy in infection treatment, especially in patients with resistant microorganisms and anatomical complications. Conclusion: Lasers can be applied as an alternative to the classic surgical and non-surgical means for periodontal procedures. Low-level laser therapy and photoactivated disinfection ensure faster bacteriolysis and affect the microorganisms locally, whereas systemic medicines influence the whole organism. Photodynamic therapy does not require maintaining high concentrations of the photosensitizer in the infected area, as it is when using antiseptics and antibiotics.

Decreased expression of ectonucleotidase E-NPP1 in leukocytes from subjects with severe asthma exacerbation

Several studies suggest that ATP and related nucleotides play a role in the pathophysiology of asthma. However, the functionality of ectonucleotidases in this disease has been scantly investigated. We studied total ectonucleotidase activity in leukocytes from patients suffering from asthma exacerbation and explored the expression of E-NTPDase 1, 2, 3, and 8, and E-NPP1, 2, and 3, in their polymorphonuclear cells by immunofluorescence and qPCR. Leukocytes from patients with mild or moderate asthma exacerbation had similar ectonucleotidase activity than leukocytes from healthy subjects, while in patients with severe asthma exacerbation, this activity was lower. Of the ectonucleotidases studied, only E-NPP1 displayed diminished immunofluorescence and a significant decrease in its mRNA expression, both in patients with severe asthma exacerbation. This reduced E-NPP1 expression could be responsible for increased amounts of ATP or other nucleotides, capable of worsening asthma exacerbation, and warranting further investigation.