Bioactive Dental Resin Composites with MgO Nanoparticles

A Review on Recently Developed Antibacterial Composites of Inorganic Nanoparticles and Non-Hydrogel Polymers for Biomedical Applications

Development of new antibacterial materials for solving biomedical problems is an extremely important and very urgent task. This review aims to summarize recent articles (from the last five and mostly the last three years) on the nanoparticle/polymer composites for biomedical applications. Articles on polymeric nanoparticles (NPs) and hydrogel-based systems were not reviewed, since we focused our attention mostly on the composites of polymeric matrix with at least one inorganic filler in the form of NPs. The fields of application of newly developed antibacterial NPs/polymer composites are described, along with their composition and synthetic approaches that allow researchers to succeed in preparing effective composite materials for medical and healthcare purposes.

Efficacy of digital guide-assisted implant restoration in anterior teeth aesthetics and its impact on labial bone mass

OBJECTIVE

To analyze the efficacy of digital guide-assisted implant restoration technique in enhancing the anterior teeth aesthetics and its impact on labial bone mass.

METHODS

We retrospectively analyzed clinical data from 90 patients who underwent maxillary anterior teeth implant restoration at The First People's Hospital of Fuyang, Hangzhou, from January 2021 to September 2023. The patients were divided into two groups: a conventional group (n=45, 45 implants, standard implant restoration) and a digital group (n=45, 45 implants, digital guide-assisted implant). We compared implant positional deviations, changes in dental plaque index (PLI), aesthetic effect scores, labial bone mass differences, and the occurrence of adverse reactions post-treatment between the two groups.

RESULTS

The digital group exhibited significantly less deviation in root position in the buccolingual and vertical directions, less neck deviation in the buccolingual and vertical directions, and less apical deviation than the conventional group (P=0.021, P=0.005, P=0.016, P=0.008, P=0.026, respectively). Three months postoperatively, the digital group demonstrated a significantly lower mean PLI (P<0.001), higher white and pink aesthetic scores (P=0.021, P=0.005), and increased alveolar ridge height and coronal and middle labial bone mass (P=0.006, P=0.015, P=0.008). Additionally, this group experienced lower incidence of adverse reactions (4.44% vs. 17.78%) compared with the conventional group (P=0.044).

CONCLUSION

The digital guide-assisted implant restoration significantly enhances implant accuracy, reduces bone resorption, improves aesthetic outcomes, and ensures higher safety.

A Review on the Current State of Microcapsule-Based Self-Healing Dental Composites

Resin-based dental composites, commonly used in dentistry, offer several advantages including minimally invasive application, esthetically pleasing appearance, and good physical and mechanical properties. However, these dental composites can be susceptible to microcracks due to various factors in the complex oral environment. These microcracks can potentially lead to clinical restoration failure. Conventional materials and methods are inadequate for detecting and repairing these microcracks in situ. Consequently, incorporating self-healing properties into dental composites has become a necessity. Recent years have witnessed rapid advancements in self-healing polymer materials, drawing inspiration from biological bionics. Microcapsule-based self-healing dental composites (SHDCs) represent some of the most prevalent types of self-healing materials utilized in this domain. In this article, we undertake a comprehensive review of the most recent literature, highlighting key insights and findings related to microcapsule-based SHDCs. Our discussion centers particularly on the preparation techniques, application methods, and the promising future of self-healing microcapsules in the field of dentistry.

Synthesis of a novel monomer "DDTU-IDI" for the development of low-shrinkage dental resin composites

OBJECTIVE

The current dental resin composites often suffer from polymerization shrinkage, which can lead to microleakage and potentially result in recurring tooth decay. This study presents the synthesis of a novel monomer, (3,9-diethyl-1,5,7,11-tetraoxaspiro[5,5]undecane-3,9-diyl)bis(methylene) bis((2-(3-(prop-1-en-2-yl)phenyl)propan-2-yl)carbamate) (DDTU-IDI), and evaluates its effect in the formulation of low-shrinkage dental resin composites.

METHODS

DDTU-IDI was synthesized through a two-step reaction route, with the initial synthesis of the required raw material monomer 3,9-diethyl-3,9-dihydroxymethyl-1,5,7,11-tetraoxaspiro-[5,5] undecane (DDTU). The structures were confirmed using Fourier-transform infrared (FT-IR) spectroscopy and hydrogen nuclear magnetic resonance (1HNMR) spectroscopy. Subsequently, DDTU-IDI was incorporated into Bis-GMA-based composites at varying weight percentages (5, 10, 15, and 20 wt%). The polymerization reaction, degree of conversion, polymerization shrinkage, mechanical properties, physicochemical properties and biocompatibility of the low-shrinkage composites were thoroughly evaluated. Furthermore, the mechanical properties were assessed after a thermal cycling test with 10,000 cycles to determine the stability.

RESULTS

The addition of DDTU-IDI at 10, 15, and 20 wt% significantly reduced the polymerization volumetric shrinkage of the experimental resin composites, without compromising the degree of conversion, mechanical and physicochemical properties. Remarkably, at a monomer content of 20 wt%, the polymerization shrinkage was reduced to 1.83 ± 0.53%. Composites containing 10, 15, and 20 wt% DDTU-IDI exhibited lower water sorption and higher contact angle. Following thermal cycling, the composites exhibited no significant decrease in mechanical properties, except for the flexural properties.

SIGNIFICANCE

DDTU-IDI has favorable potential as a component which could produce volume expansion and increase rigidity in the development of low-shrinkage dental resin composites. The development of low-shrinkage composites containing DDTU-IDI appears to be a promising strategy for reducing polymerization shrinkage, thereby potentially enhancing the longevity of dental restorations.

Mechanical and Antimicrobial Properties of Boron Nitride/Methacrylic Acid Quaternary Ammonium Composites Reinforced Dental Flowable Resins

Dental resin composites (DRCs) are commonly used to restore teeth affected by dental caries or defects. These materials must possess excellent properties to withstand the complex oral environment. The objective of this study was to prepare and characterize Boron nitride nanosheets (BNN)/ dimethyl amino hexadecyl methacrylate (DMAHDM) composites (BNN/DMA), and to evaluate them as functional fillers to enhance the mechanical and antimicrobial properties of dental resins. The BNN/DMA composites were successfully prepared under the theoretical guidance of molecular dynamics (MD), and then the physicochemical and morphological characterization of the BNN/DMA composites were carried out by using various test methods, such as FT-IR, XRD, UV-vis spectroscopy, SEM, TEM, and AFM. It was doped into the dental flowable resin in a certain proportion, and the results showed that the flexural strength (FS), elastic modulus (EM), compressive strength (CS), and microhardness (MH) of the modified resin composites were increased by 53.29, 47.8, 97.59, and 37.1%, respectively, with the addition of 0.8 wt % of BNN/DMA composite fillers. It has a good inhibition effect on Streptococcus mutans, with an inhibition rate as high as 90.43%. Furthermore, this effect persists even after one month of aging. In conclusion, the modification of flowable resins with low-concentration BNN/DMA composites favorably integrates the mechanical properties and long-term antimicrobial activity of dental resins. At the same time, they have good biocompatibility and do not affect the aesthetics. The BNN/DMA composite modified flowable resin has the potential to become a new type of antimicrobial dental restorative material.

Antibacterial Agents for Composite Resin Restorative Materials: Current Knowledge and Future Prospects

Resin composites became the material of choice for direct restorations in anterior and posterior teeth. Despite the revolutionary improvement in the material, restoration failure is still a major drawback due to the material's inherent negative properties, including a lack of antibacterial effects. Therefore, many attempts have been made to incorporate antibacterial agents into resin composite materials to improve their antimicrobial properties and prevent secondary caries formation. Multiple laboratory studies have been conducted using different antibacterial agents, such as quaternary ammonium compounds, methacryloyloxydodecylpyridinium bromide, magnesium oxide nanoparticles, chlorhexidine, and chitosan. This review provides a glance at the current status of these materials and the research directions needed in the future.

Ion incorporation into bone grafting materials

The use of biomaterials in regenerative medicine has expanded to treat various disorders caused by trauma or disease in orthopedics and dentistry. However, the treatment of large and complex bone defects presents a challenge, leading to a pressing need for optimized biomaterials for bone repair. Recent advances in chemical sciences have enabled the incorporation of therapeutic ions into bone grafts to enhance their performance. These ions, such as strontium (for bone regeneration/osteoporosis), copper (for angiogenesis), boron (for bone growth), iron (for chemotaxis), cobalt (for B12 synthesis), lithium (for osteogenesis/cementogenesis), silver (for antibacterial resistance), and magnesium (for bone and cartilage regeneration), among others (e.g., zinc, sodium, and silica), have been studied extensively. This review aims to provide a comprehensive overview of current knowledge and recent developments in ion incorporation into biomaterials for bone and periodontal tissue repair. It also discusses recently developed biomaterials from a basic design and clinical application perspective. Additionally, the review highlights the importance of precise ion introduction into biomaterials to address existing limitations and challenges in combination therapies. Future prospects and opportunities for the development and optimization of biomaterials for bone tissue engineering are emphasized.