List of Abstracts

Several procedures are used in the development of biomaterials for dentistry applications. The aesthetic quality of the biomaterial has been a concern. However, alterations to biomaterial composition must be carried out carefully to avoid deleterious effects on the environment when the materials are discarded after use. The incorporation of metallic nanoparticles into dental materials has emerged as a promising strategy to enhance functional properties. This procedure has potential aesthetic effects that remain a critical concern in orthodontic applications. This study aimed to evaluate the influence of copper nanoparticles (CuNPs) on the color properties of a resin-based composite used for orthodontic attachments. Small amounts of nanoparticles were added to the resin. Different concentrations of CuNPs and specimen thicknesses were analyzed. Disc-shaped specimens were prepared using a commercial resin composite modified with CuNPs at concentrations of 0.05% and 0.075% (wt%). The control group was a sample without nanoparticles. Samples were fabricated with thicknesses of 1.0 mm and 2.0 mm to analyze the influence of optical properties. Color measurements were performed using a spectrophotometer based on the CIE Lab* system, and color differences (ΔE) were calculated. The results demonstrated that the incorporation of CuNPs led to measurable color changes compared to the control group, with higher concentrations promoting greater ΔE values. This behavior can be attributed to the intrinsic optical properties of copper nanoparticles, including increased light absorption and scattering within the resin matrix. Additionally, specimen thickness significantly influenced color outcomes, with 2 mm samples exhibiting higher opacity and greater color variation due to increased light attenuation along the optical path. These results indicate that both nanoparticle concentration and material thickness play a key role in determining the optical performance of resin composites. Although copper nanoparticles offer potential functional benefits, their impact on color must be carefully controlled to ensure aesthetic acceptability in dental applications and to avoid environmental impact upon disposal after use.

Oropharyngeal squamous cell carcinoma (OSCC) exhibits a rising global incidence, particularly driven by human papillomavirus (HPV) infection, which acts as a distinct etiologic agent with specific genotypic heterogeneity influencing tumor biology and clinical outcomes. This study prospectively investigates HPV-positive and HPV-negative OSCC patients at Brazilian Cancer Hospital I/INCA, Rio de Janeiro. The aim is to correlate specific HPV genotypes with cytopathic effects—such as koilocytosis, nuclear hyperchromasia, and multinucleation—across different tumor stages. We evaluate the efficacy of exfoliative cytology combined with an expanded molecular genotyping approach (Multi HPV Flow Chip, XGEN®) capable of detecting 35 HPV genotypes. This methodology represents a significant advancement over conventional programs limited to types 16 and 18, potentially reducing false negatives and enhancing diagnostic precision. Samples are collected using sterile brushes for the preparation of smears, which are subsequently fixed in 96% ethanol and submitted to Papanicolaou staining for cytological analysis. In addition to the brushes, oropharyngeal swabs are collected for genotyping. Molecular detection is performed via PCR and reverse hybridization. Preliminary analysis of eleven samples has already identified morphological changes consistent with viral cytopathic effects. We anticipate that high-risk genotypes (notably HPV-16 and 18) will predominate, while also addressing the role of multiple subtype coinfections in tumor behavior. The validation of these cytological findings through specific genotyping highlights exfoliative cytology as a minimally invasive, cost-effective, and precise tool for early OSCC detection. This research provides crucial insights for targeted surveillance strategies and personalized therapeutic management, ultimately aiming to improve patient prognosis and quality of life in the context of public health oncology.

Some cutting instruments used in various surgical, medical, and dental procedures can be reused. Professionals should analyze disposal methods and the possibilities of reusing instruments without compromising the procedure, thus minimizing environmental impact. It is essential to analyze the type, shape, and application of surgical instruments to assess their feasibility for reuse. Surgical instruments, such as forceps, scalpels, bone chisels, scrapers, and surgical drills, are commonly reused. There is a protocol for handling, cleaning, and sterilization of these instruments to prevent the transmission of pathogens and infections between patients. Single-use instrument kits have a greater environmental impact than reusable ones. Environmental impacts encompass greenhouse gas emissions, water consumption, and the use of natural resources. In the present work, the possibility of reusing a cutting instrument named Micro Blade Tunnel [1], commonly used in periodontal plastic surgeries, and drills used to prepare the site for dental implant placement was analyzed [2]. The instruments were to be properly cleaned, decontaminated, and inspected before each use. The naked-eye analysis showed no changes in the instruments' physical integrity after multiple uses. The analysis of all instruments using a scanning electron microscope revealed only slight wear and surface-roughness modification. Naked-eye inspection is an inadequate procedure for identifying small defects on the instrument's reused surface. During osteotomy to prepare the site for dental implant placement, bone heating can occur, compromising osseointegration. During dental implant insertion site preparation, the surgeon must control the drill rotation speed, the compression force, the irrigation, and the instrument's cutting capacity to avoid overheating the bone. The electron microscopy analysis showed that the drill, after up to 48 uses and sterilizations, did not exhibit signs of wear, corrosion, or heating at temperatures considered critical for inducing bone necrosis. It is possible to conclude that the Micro Blade Tunnel can be safely reused up to three times. Drills can be used up to 40 times without compromising the surgical procedure. It is concluded that environmental considerations are relevant when making decisions about materials and devices used in dental and medical surgery practice.

Tranexamic acid (TXA) is widely used as an antifibrinolytic agent in surgical procedures, promoting hemostasis and potentially influencing the tissue repair process. This study aimed to evaluate the effect of TXA on bone repair in an experimental model of a critical-size defect in rat calvaria. Twenty male Wistar rats were divided into two groups (Control and TXA) and two evaluation periods, 14 and 28 days. Bone defects measuring 5 mm in diameter were created in the calvaria and treated with a blood clot (control group) or a clot soaked in TXA 25 mg/mL (TXA group); all defects were covered with a collagen membrane. Histomorphometric analysis was performed to quantify the area of new bone formation (µm² × 10⁵). The results revealed that the TXA group showed a smaller area of newly formed bone compared to the control group, especially at 28 days (p<0.05), indicating an inhibitory effect of the drug on bone regeneration. In the Clot group, a significant increase in bone formation was observed over time (p = 0.0065), which was not observed in the TXA group. Histological analysis confirmed these findings, showing less defect filling and reduced trabecular organization in TXA-treated specimens, as well as the presence of intense inflammatory infiltrate. It is concluded that, despite its hemostatic properties, topical use of TXA may negatively affect the bone repair process in critical defects, probably by interfering with the physiological dynamics of fibrinolysis and with cellular events essential for new bone formation.

This exploratory study assessed the feasibility of fabricating lithium disilicate (Li₂O₅Si₂) ceramic structures using robocasting, an additive manufacturing technique, and compared their mechanical, chemical, and microstructural properties with those produced by conventional subtractive manufacturing. It was hypothesized that lithium disilicate could be successfully processed via robocasting and that the resulting structures would demonstrate mechanical performance comparable to those obtained through traditional methods.

Specimens were divided into two groups: subtractive manufacturing (SM) and additive manufacturing via robocasting (AR). For the AR group, Li₂O₅Si₂ powder was blended with ammonium polyacrylate, hydroxypropyl methylcellulose, and a polyelectrolyte to produce a printable colloidal gel. Disc-shaped samples were designed using CAD software, and fabrication was carried out using a custom-built direct ink writing (DIW) 3D printer. In the SM group, samples were milled from pre-crystallized ceramic blocks to match the dimensions of the AR specimens. All samples were subsequently crystallized at 840 °C.

Mechanical properties were determined through biaxial flexural strength (BFS) testing and Vickers hardness measurements. Microstructural and compositional analyses were performed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS), while chemical bonding and phase composition were evaluated using FTIR-ATR and X-ray diffraction (XRD), respectively.

The AR group exhibited lower biaxial flexural strength (110.05 MPa ±33.91) and hardness (3.87 GPa ±0.30) compared to the SM group (295.09 MPa ±63.98 and 5.53 GPa ±0.14, respectively). EDS results indicated comparable elemental composition between groups. However, FTIR-ATR spectra revealed more pronounced crystalline-related peaks in the SM samples, and XRD analysis suggested reduced conversion of lithium metasilicate to lithium disilicate in the AR group. SEM observations demonstrated a more porous microstructure in the 3D-printed specimens.

Overall, the results confirm that lithium disilicate ceramics can be fabricated via robocasting. Nevertheless, the superior mechanical performance observed in the subtractive manufacturing group highlights current limitations of the additive approach. These differences are likely associated with incomplete phase transformation and increased porosity in the printed structures. Despite these challenges, the findings provide valuable insights for the advancement of sustainable and efficient ceramic fabrication strategies for biomedical and dental applications.

Rehabilitation of severely atrophic tissues remains a major challenge across multiple surgical disciplines, including implant dentistry, orthopedics, and reconstructive surgery, particularly due to limited vascularization and reduced regenerative capacity of host tissues. Conventional biomaterials, such as bone substitutes and barrier membranes, provide structural support but often lack the biological activity necessary for optimal integration. This limitation has led to the development of hybrid regenerative approaches that combine structural biomaterials with biologically active components.

The purpose of this study is to evaluate the role of adipose-derived tissue as a bioactive adjunct in combination with conventional biomaterials for implant-based and reconstructive procedures. Adipose tissue, rich in stromal vascular fraction (SVF) and adipose-derived stem cells (ADSCs), exhibits angiogenic and immunomodulatory properties that may enhance tissue healing and integration.

A translational approach was employed, integrating current literature from oral and maxillofacial surgery, orthopedics, and plastic surgery with clinical regenerative strategies involving the association of adipose-derived grafts with bone substitutes, platelet concentrates, and barrier membranes. Emphasis was placed on understanding how adipose-derived components influence vascularization, cellular recruitment, and biomaterial performance.

The histological  findings indicate that hybrid strategies incorporating adipose-derived tissue improve the biological environment of grafted areas, promoting enhanced vascularization, faster integration, and improved tissue quality. These effects appear consistent across different anatomical sites and surgical applications.

In conclusion, the combination of adipose-derived grafts with conventional biomaterials represents a promising multidisciplinary strategy. Rather than replacing existing materials, adipose tissue acts as a biological enhancer, supporting a shift toward biologically driven regenerative approaches in modern surgery.

Guided bone regeneration (GBR) relies on barrier membranes to maintain space and prevent soft tissue invasion during bone healing. Among available biomaterials, resorbable synthetic membranes based on polydioxanone (PDO) have gained attention due to their biocompatibility and predictable degradation profile. However, the influence of membrane thickness on the physicochemical behavior of PDO over time remains insufficiently understood.

This study aimed to evaluate the effect of membrane thickness on mass variation and pH changes of PDO membranes during in vitro degradation. Membrane samples with two different thicknesses (0.25 mm and 0.50 mm) were immersed in phosphate-buffered saline (PBS) and maintained at 37 °C. Analyses were performed at 8, 18, 39, 55, and 99 days. Mass variation was determined using an analytical balance after controlled dehydration, and pH values were measured in the immersion medium. 

Both membrane groups exhibited a significant reduction in mass over time (p<0.05). Thicker membranes (0.50 mm) consistently showed higher mass values at all time points, indicating a slower degradation profile. A progressive decrease in pH was observed throughout the experimental period, with significantly lower pH values in the thicker membranes from day 8 onward (p<0.05). These findings suggest that increased membrane thickness reduces water diffusion and delays the release of degradation byproducts, influencing local physicochemical conditions.

Within the limitations of this in vitro study, membrane thickness significantly affects the degradation behavior of PDO, impacting both mass loss and pH variation over time. These factors may influence membrane stability and performance in GBR procedures, particularly in clinical scenarios requiring prolonged barrier function.

Titanium and its alloys are extensively employed in dental and orthopedic implants due to their excellent mechanical strength, corrosion resistance, and biocompatibility [1]. Nevertheless, conventional alloys still face limitations related to elastic modulus mismatch with bone tissue and limited intrinsic bioactivity, which may compromise long-term implant performance [2]. In this context, the development of β-type titanium alloys stabilized with non-toxic elements such as Nb and Mo has emerged as a promising approach to achieve improved mechanical compatibility and enhanced biological response [3]. In this study, metastable β-type titanium alloys were produced by arc melting followed by homogenization treatments, aiming to control phase stability and microstructural features. Structural and microstructural characterization using XRD, SEM, EBSD, and TEM revealed a predominantly β-phase matrix with nanoscale heterogeneities and the presence of metastable phases, such as ω, which are known to influence mechanical behavior and elastic modulus. These characteristics are particularly relevant for dental and orthopedic implants, where mechanical compatibility with surrounding bone is critical to reduce stress shielding effects. To further enhance biological performance, micro-arc oxidation (MAO) surface modification was applied to the alloys [4]. The process enabled the formation of porous TiO₂ coatings with controlled morphology and chemistry. Increasing the current density during MAO treatment resulted in higher surface roughness, improved hydrophilicity, and the formation of rutile phases, all of which are favorable for cell adhesion and osseointegration. In addition, incorporating copper into the coatings can confer antibacterial properties, particularly important in dental applications where infection control is a major concern [5]. The combination of optimized bulk microstructure and tailored surface properties provides a synergistic strategy for improving both mechanical and biological performance of titanium-based implants. In dental applications, these materials can accelerate osseointegration, improve implant stability, and reduce the risk of peri-implant infections. In broader biomedical contexts, these advances support the development of multifunctional implants that interact more effectively with the physiological environment. Overall, this study highlights the potential of integrating β-type alloy design with advanced surface engineering techniques to develop next-generation titanium biomaterials. These materials represent a significant step toward more efficient, durable, and biologically active implants for dental and medical applications. (Financial support: CNPq, grants #314.810/2021-8 and #421.677/2023-6, and FAPESP, grant #2024/01.132-2).

Hydroxyapatite (Hap) is the main inorganic component of human bone and dental tissues. HAp (PO₄)₆(OH)₂) is approximately 65% ​​of bone mass and up to 96% of dental enamel [1]. Due to its similarity in composition and crystalline structure to natural bone, this material exhibits high biocompatibility, bioactivity, and osteoconductivity. HAp favors the adhesion and proliferation of osteoblastic cells [2].
For clinical applications, it is important to understand the thermal behavior and structural stability of hydroxyapatite. In this work, differential scanning calorimetry (DSC) was used to characterize HAp. DSC allows the identification of thermal events, such as phase transformations and decomposition processes, from the variations in heat flow associated with the sample [3]. Three samples of the commercial biomaterial (Blue Bone ® ) manufactured by Regener Biomateriais (Curitiba, Brazil) were analyzed. Blue Bone ® is composed of nanohydroxyapatite and β-tricalcium phosphate (β-TCP), in an approximate ratio of 80/20 [4]. The analyses were performed in a Shimadzu DSC 60 calorimeter (Shimadzu, Kyoto, Japan). Each sample, with a mass of approximately 4 mg, was placed in aluminum crucibles and subjected to a heating ramp from 25 to 550°C, at a rate of 5 °C/minute. The results obtained showed the presence of a few thermal events throughout the analyzed temperature range. This behavior indicates that the material exhibits good thermal stability, with a predominance of well-defined crystalline phases and a significant absence of volatile compounds or organic residues.
Furthermore, the combination of hydroxyapatite and β-TCP phases is relevant from a biological point of view: while β-TCP exhibits greater solubility and can contribute to the release of calcium and phosphate ions, hydroxyapatite tends to ensure greater structural stability to the material [5]. The results of the DSC analysis indicate that the Blue Bone ® biomaterial exhibits thermal behavior compatible with materials already processed and intended for biomedical applications. The absence of multiple complex thermal peaks suggests that the material possesses good quality and stability, important characteristics for its use in bone regeneration procedures. The biphasic hydroxyapatite is a suitable biomaterial for clinical applications, especially in situations requiring structural support combined with bioactivity, and aligns with more sustainable practices in biomaterial development.

Lip repositioning techniques associated with myotomy have demonstrated consistent results in reducing gingival display in patients with gummy smile. However, long-term stability remains a significant clinical challenge, mainly due to the capacity for reorganization of intradermal muscle fibers during the healing process. This phenomenon is directly associated with the partial relapse observed in some cases, even when the surgical technique is properly executed.

In this context, modulation of the healing process emerges as a key factor for therapeutic success. The use of non-resorbable biomaterials, such as polyester sutures, inserted in a delayed post-operative phase, has been proposed as a therapeutic approach to interfere with muscle reorganization and induce controlled fibrosis, acting as a physical barrier against relapse. This approach represents a shift in paradigm, moving the focus from the surgical intervention itself to the active control of the healing process.

Clinical outcomes observed with this strategy demonstrate improved stability of results over medium-term follow-up, reducing the need for retreatment and, consequently, the cumulative consumption of clinical materials and interventions. From this perspective, stability can also be understood as a component of sustainability in healthcare, as longer-lasting treatments imply a lower use of resources throughout the therapeutic cycle.

Despite these promising results, the clinical application of the technique still presents relevant challenges. The insertion of the sutures, as well as the definition of the ideal number and thickness of the material, depend on operator skill and present variability. Furthermore, the creation of a functional barrier using autogenous tissues remains limited in terms of predictability and volumetric stability, reinforcing the need for alternative solutions.

These limitations open space for the development of new biomaterials capable of acting not only as structural elements but also as functional modulators of the healing process. Ideally, such materials should combine adequate mechanical performance, biological integration, and reduced environmental impact, aligning clinical efficiency with sustainability principles.

Therefore, the present work not only introduces a therapeutic approach for relapse control but also proposes a new perspective on healing modulation as a central strategy for achieving stable, predictable, and sustainable outcomes in esthetic periodontal surgery.

With advances in regenerative dental treatments, platelet- and leukocyte-rich fibrin (PRF) membranes have become widely used tools in tissue engineering for their ability to enhance bone grafts, promote the regeneration of hard and soft tissues, stimulate angiogenesis, and modulate cellular differentiation and migration. The present study aimed to quantify insulin-like growth factor 1 (IGF-1) in PRF membranes from smokers and non-smokers, in accordance with the U.S. Preventive Services Task Force (USPSTF) guidelines. The sample consisted of 28 individuals, including 14 smokers and 14 non-smokers. Six venous blood samples (10 mL each) were collected and placed in silica-coated plastic tubes, which were allowed to rest for five minutes to enable matrix organization and fibrin clot formation. The samples were then centrifuged at 2700 rpm (408 g) for 12 minutes at room temperature to obtain the PRF membranes. After membrane processing, IGF-1 quantification was performed using an enzyme-linked immunosorbent assay (ELISA). Data were subjected to the Student's t-test with a significance level of 5%. The results demonstrated no statistically significant difference in IGF-1 levels between PRF membranes derived from smokers and non-smokers (p = 0.258), with mean values of 1.82 ng/mL in the control group and 1.62 ng/mL in the smoker group. It was concluded that smoking did not have a significant influence on IGF-1 concentration in the evaluated PRF membranes.

Hyaluronic acid-based gel is widely used for facial rejuvenation due to its biocompatibility and viscoelastic properties. The disadvantage of hyaluronic acid is the
lower clinical durability due to enzymatic and oxidative degradation. The addition of hydroxyapatite (HA) and glutathione to hyaluronic acid can improve the gel's properties. The HA provides structural support and biostimulatory potential. Glutathione may act as an antioxidant, delaying oxidative degradation of the gel and preserving its mechanical integrity. This study aimed to analyze whether the addition of hydroxyapatite and glutathione changes the rheological behavior of a crosslinked hyaluronic acid dermal filler. The new composite was compared with the pure hyaluronic acid. Tests were performed using oscillatory rheometry with a parallel-plate geometry, including an amplitude sweep to identify the linear viscoelastic property and a frequency sweep to evaluate the material's dynamic response. The pure gel exhibited a storage modulus of approximately 600-750 Pa. The composite reached values of 1300-1400 Pa, demonstrating increased stiffness, cohesiveness, and lifting capacity. In both formulations, G’ remained higher than G”, confirming predominantly elastic behavior. The modified composite exhibited rheological behavior comparable to that of highly elastic structural fillers. It is possible to conclude that the addition of hydroxyapatite and glutathione significantly alters the hyaluronic acid's rheology, increasing its potential for use in deep planes and facial areas requiring greater structural support.

Clear Aligner Therapy (CAT) has seen rapid global adoption, with over 14 million patients treated to date. This growth entails a substantial environmental footprint, generating an estimated 1,456 tons of plastic waste from aligners and nearly 11,000 tons from non-recyclable 3D-printed resin models. The traditional thermoforming process is inherently inefficient, with up to 80% of the thermoplastic sheet becoming waste. Furthermore, each patient's dental treatment can require up to 100 aligners. During aligner manufacturing, significant material loss occurs if treatment plans are refined and unused trays are discarded. Environmental concerns extend beyond bulk waste to include microplastic and nanoplastic pollution. Studies indicate that aligners release approximately 11 microparticles per day into the oral cavity during use. The disposal of aligners and leftover manufacturing materials is a major challenge and difficult to solve. This problem is similar to the disposal of contaminated medical waste. One solution to avoid discarding aligners into the environment is incineration. However, this incineration process releases toxic compounds such as benzene and tetrahydrofuran, exacerbating the problem. To mitigate these impacts, the industry is adopting the "4R" framework (Reduce, Reuse, Recycle, Rethink). Key innovations include staged production to prevent oversupply and direct 3D printing, which eliminates the need for physical molds. Emerging research into biodegradable bioplastics and specialized recycling partnerships represents an essential step toward a circular economy in orthodontics.

Hydroxyapatite (HAp) is the main inorganic constituent of bone and dental tissues, providing rigidity and mechanical resistance. Due to its composition and crystalline structure, which are like those of natural bone mineral, this biomaterial exhibits excellent biocompatibility, bioactivity, and osteoconductivity. These characteristics make HAp the most widely researched bioceramic for use in hard tissue repair and tissue engineering [1]. This work aims to present a literature review of synthesis methodologies and clinical applications of hydroxyapatite in regenerative procedures. HAp synthesis methodologies define their final properties and can be divided into three categories: wet routes, dry routes, and biogenic extraction. Wet routes, such as chemical precipitation, the sol-gel method, and hydrothermal synthesis, are the most versatile and allow precise control over nanocrystal morphology and size [4]. The hydrothermal method, conducted under controlled pressure and temperature, allows the production of high-purity crystals. In this case, organic modifiers are used to produce needle- or rod-shaped particles. With dry routes in the solid state, thermal or mechanical energy is used
via milling to promote the reactions. Dry routes are preferred for large-scale production, although they offer less control over grain uniformity. In biogenic extraction, natural materials such as crustaceans, eggshells, and bovine bones are used. This route has sustainable and low-cost characteristics [5]. The applications of HAp in dentistry and medicine are vast, ranging from filling critical bone defects to coating metallic implants to accelerate osseointegration. In dentistry, HAp is used to treat dentin hypersensitivity, promote enamel remineralization, and prevent caries. As a platform for controlled drug release, its porous structure enables the adsorption of hydrophilic and hydrophobic molecules, and it is being investigated for the delivery of antibiotics and chemotherapeutic agents in osteosarcoma treatment [2]. Recent advances explore ionic doping of HAp with elements such as strontium, zinc, or magnesium to mimic the properties of human bone, improve mechanical resistance, and enhance the biomaterial's antibacterial properties. With additive manufacturing, such as 3D printing, it is possible to create customized scaffolds with controlled porosity for each clinical need [3]. Based on the literature, it is possible to conclude that hydroxyapatite is well established for clinical use and indispensable in regenerative surgeries. The evolution of synthesis techniques enables fine-tuning of their properties. Integration with technologies such as ion doping and 3D printing reduces the gap between synthetic substitutes and the complex functionality of bone tissue.

This study evaluates the potential of biphasic calcium phosphate (BCP) scaffolds fabricated by 3D printing via robocasting for the regeneration of critical-sized defects in long bones. The scaffolds were engineered with an interconnected porous architecture to enhance osteoconductive properties. Physicochemical characterization included density and porosity measurements obtained through helium pycnometry, revealing a density of 2.98 ± 0.01 g/cm³ and a porosity of 48.5 ± 1.5%. Mechanical performance was assessed by uniaxial compression testing, demonstrating that the scaffolds possess sufficient compressive strength for load-bearing applications. Surface morphology and elemental composition were investigated using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), confirming the presence of a well-defined porous structure and the expected elemental constituents. X-ray Diffraction (XRD) analysis verified the crystalline phases of BCP. Overall, the findings indicate that the developed scaffolds exhibit biocompatibility and osteoconductivity, supporting guided bone regeneration and remodeling in critical defects of long bones. The combination of suitable mechanical properties and favorable surface characteristics highlights their potential for clinical translation in the treatment of extensive bone defects.