Simulating the Intraoral Aging of Dental Bonding Agents: A Narrative Review

Despite their popularity, resin composite restorations fail earlier and at higher rates than comparable amalgam restorations. One of the reasons for these rates of failure are the properties of current dental bonding agents. Modern bonding agents are vulnerable to gradual chemical and mechanical degradation from a number of avenues such as daily use in chewing, catalytic hydrolysis facilitated by salivary or bacterial enzymes, and thermal fluctuations. These stressors have been found to work synergistically, all contributing to the deterioration and eventual failure of the hybrid layer. Due to the expense and difficulty in conducting in vivo experiments, in vitro protocols meant to accurately simulate the oral environment’s stressors are important in the development of bonding agents and materials that are more resistant to these processes of degradation. This narrative review serves to summarize the currently employed methods of aging dental materials and critically appraise them in the context of our knowledge of the oral environment’s parameters.

Rheological and Mechanical Properties of Resin-Based Materials Applied in Dental Restorations

Resin-based materials have been prevalent for dental restorations over the past few decades and have been widely used for a variety of direct and indirect procedures. Typically, resin-based dental materials are required to be flowable or moldable before setting and can provide adequate mechanical strength after setting. The setting method may include, but is not limited to, light-curing, self-curing or heating. In this review, based on different indications of resin-based dental materials (e.g., dental filling composite, dental bonding agent, resin luting cement), their rheological and mechanical properties were reviewed. Viscous and flexible properties were focused on for materials before setting, while elastic properties and mechanical strength were focused on for materials after setting. At the same time, the factors that may affect their rheological and mechanical properties were discussed. It is anticipated that the insightful information and prospections of this study will be useful to the future development and fabrication of resin-based dental restorative materials.

Modelling ATR-FTIR Spectra of Dental Bonding Systems to Investigate Composition and Polymerisation Kinetics

Component ratios and kinetics are key to understanding and optimising novel formulations. This warrants investigation of valid methods. Attenuated Total Reflectance Fourier Transform Infra-Red (ATR)-FTIR spectra of separate primers/adhesives were modelled using summed spectra of solvents (water, ethanol), methacrylate monomers (HEMA (hydroxyethyl methacrylate), Bis-GMA (bisphenol A glycidyl methacrylate), and 10-MDP (10-methacryloyloxydecyl dihydrogen phosphate)), and fillers, multiplied by varying fractions. Filler loads were obtained following their separation from the adhesives, by analysing three repetitions (n = 3). Spectral changes during light exposure at 37 °C (20 s, LED 1100–1330 mW/cm2) were used to determine polymerisation kinetics (n = 3). Independent samples T-test was used for statistical analysis (significance level of 5%). FTIR modelling suggested a primer solvent percentage of OBFL (Optibond FL) (30%) was half that of CFSE (Clearfil SE 2) (60%). OBFL included ethanol and water, while CFSE included only water. Monomer peaks were largely those of HEMA with lower levels of phosphate monomers. OBFL/CFSE adhesive model spectra suggested that both contained equal volumes of Bis-GMA/HEMA, with CFSE having 10-MDP. Filler levels and spectra from OBFL (48 wt.%) and CFSE (5 wt.%) were different. Both systems reached a 50% conversion rate within seconds of light exposure. The final conversion for OBFL (74 ± 1%) was lower compared to CFSE (79 ± 2%) (p < 0.05). ATR-FTIR is a useful method to investigate relative levels of main components in bonding systems and their polymerisation kinetics. Such information is valuable to understanding such behaviour.

Adhesion of Teeth

Dental bonding materials are widely used in dentistry and there are several available kinds. However, in recent years, there has been no further research into dental bonding materials, with most dentists focusing on dental implants and orthodontics. In this paper, we systematically review the technology of tooth bonding in recent years and summarize the existing literature for potential innovation and direction of future research. First, the theoretical research on dental assembly materials and bonding mechanism was reviewed. Then, we reviewed the bonding of teeth, the bonding of metal alloy prosthesis, and the measurement of bond strength. Finally, the future development of dental bonding technology was evaluated. It is hoped that more dentists will be able to treat patients and update research on bonding materials in the field of teeth bonding to bring a new era to the restoration of teeth in the future.

Conservative Substitution of Fractured Ceramic Onlays Using Self-Adhesive Cement: Case Report

The advances in bonding of ceramics and self-adhesive resin cements to tooth structure make this treatment a feasible alternative to restore posterior teeth. This case report described the removal of two fractured onlays and the fabrication of new lithium disilicate onlays cemented with self-adhesive resin cement. The rationale for various choices in this treatment protocol is detailed with reference to the pertinent literature. It is concluded that the clinical success of the technique depends on the correct identification of the case for which this treatment is appropriate and on the successful execution of the clinical steps involved. Keywords: Dental Cements. Resin Cements. Dental Bonding. ResumoOs avanços na adesão de cerâmicas e cimentos resinosos autoadesivos à estrutura dentária tornam este tratamento uma alternativa viável para restaurar os dentes posteriores. Ester relato de caso descreveu a remoção de duas onlays fraturadas e confecção de novas onlays de dissilicato de lítio cimentadas com cimento resinoso auto-adesivo. A justificativa para várias escolhas neste protocolo de tratamento é detalhada com referência à literatura pertinente. O sucesso clínico da técnica depende da correta identificação do caso para o qual este tratamento é adequado e da execução bem-sucedida das etapas clínicas envolvidas. Palavras-chave: Cimentos Dentários. Cimentos de Resina. Colagem Dentária.