Advances in Dental Materials

Background and Objectives: Contemporary caries treatment seeks to preserve hard dental tissues as well as to promote lesion remineralization and biological tissue regeneration. While fluoride-based treatments remain the gold standard, their effectiveness has limitations, prompting interest in innovative remineralization technologies. Nano-hydroxyapatite (nano-HA) varnish and self-assembling peptide (SAP) P11-4 are promising biomimetic materials that promote enamel repair, yet long-term data on their efficacy are limited. The objectives of this study were to evaluate the effectiveness of nano-HA varnish and peptide P11-4 in restoring enamel surface hardness after artificial lesions in vitro and to compare them to a control group and fluoride varnish. Materials and Methods: Artificial enamel lesions were created on the buccal surfaces of 36 extracted human molars, which were randomly divided into four groups (n = 9): control, peptide P11-4, fluoride varnish, and nano-hydroxyapatite varnish. After applying the materials as per manufacturer instructions, specimens were stored in artificial saliva for 14 days. Enamel surface hardness was measured using the Vickers hardness test (HV) at baseline, after demineralization, and after remineralization. Statistical analysis was performed with “IBM SPSS 27.0” using non-parametric Kolmogorov–Smirnov, Kruskal–Wallis, Dunn’s, and Wilcoxon tests. Results: The mean baseline enamel hardness value was 323.95 (SD 33.47) HV. After 14 days of demineralization, the mean surface hardness of artificial enamel lesions significantly plummeted to 172.17 (SD 35.96) HV (p = 0.000). After 14 days of remineralization, the mean value significantly increased to 213.21 (SD 50.58) HV (p = 0.001). The results of the study revealed statistically significant enamel remineralization of the peptide P11-4 group in regard to the demineralized enamel (p < 0.05). In contrast, there were no significant results in other treatment groups (p > 0.05). Remineralization of enamel was the highest in samples from the P11-4 group (54.1%), followed by the nano-HA group (35.4%), FV group (17.8%), and control group (11.2%). There was a significant difference (p < 0.05) in the remineralizing ability between the peptide P11-4 and all other treatment groups. Conclusions: Self-assembling peptide P11-4 effectively remineralized artificial enamel lesions and proved to be significantly more effective compared to fluoride varnish and nano-hydroxyapatite varnish, showcasing its superior performance as a remineralizing agent. Full article

Dental implant therapy is a widely used clinical procedure for restoring missing teeth in patients. Zirconia implants were introduced as an alternative to titanium implants due to their excellent biocompatibility and esthetic properties. The nuclear factor kappa B (NF-κB) signalling pathway is responsible for multiple aspects of innate and adaptive immune functions and serves as a significant and crucial mediator of inflammatory processes. The dysregulation of NF-κB activation induces pathological processes in multiple diseases. The purpose of this study was to investigate the activation of the NF-κB pathway upon stimulation with tumour necrosis factor (TNF)-α in osteoblast-like cells (MG-63) cultured on zirconia surfaces in comparison to titanium surfaces. Several methods such as immunoblot, immunofluorescence, MTT assay, and flow cytometry were used in this study. We observed that human recombinant TNF-α caused a strong activation of the NF-κB pathway on both zirconia and titanium discs and in wells without any discs. This activation was marked by the upregulation of MHC class I proteins in MG-63 cells grown on both titanium and zirconia discs; however, there was no effect on MHC class II protein expression. In summary, the present study has shown that TNF-α stimulation equally activates the NF-κB pathway in MG-63 cells cultured on both titanium and zirconia surfaces. Full article

Objectives: This retrospective cohort study aimed to compare and evaluate the 1-year stability of two Korean implant brands, Osstem and Toplan, both treated with alumina- sandblasting and acid- etching (SA) surface modification. Methods: This retrospective analysis evaluated patients with American Society of Anesthesiologists grade I or II, >20 years, with alveolar bone volume suitable for implant placement, who received immediate or delayed placement after extraction, and with Osstem (n = 57) or Toplan (n = 87) implants. The insertion torque value (ITV) measured on the day of implant placement and the implant stability quotient (ISQ) measured on the day of implant placement, 1 month post-surgery, and 2–3 months after implantation were analyzed. Results: Both implants had significantly increased ISQs over time, and the ISQs did not significantly differ between Osstem and Toplan implants at any time point. Osstem implants showed significantly higher ISQs in D2 than in D3 bone, and in the mandible than in the maxilla at all time points. Toplan implants with diameters >4.0 mm showed higher initial ISQs. Osstem implants showed a significant correlation between ITV and ISQ on the day of placement (r = 0.349, p < 0.01) but not at later time points. For Toplan implants, no significant correlation was confirmed between ITV and ISQ at any time point. At the 1-year follow-up, both implants were still providing functional service. Conclusions: Osstem and Toplan implants with SA surface treatment showed a high level of stability for 1 year, and no significant difference in stability was observed between the two implants. Both implants are considered clinically reliable products. Full article

Background: Dental restoration success relies on the physical properties of luting cements. Luting cements fill the space between teeth and the restoration, provide retention and protection from occlusal forces, and act as a barrier to microleakages in the oral environment. Objective: This review aims to evaluate and compare the solubility of the three most used dental luting cements: glass ionomer (GI), resin-modified glass ionomer (RMGI), and resin cement (RC). Methods: The studies selected for review compared the solubilities of combinations of GI, RMGI, and RC in solutions with different pH levels to replicate acidic oral pH. Results: A review of the studies concluded that resin cement had the overall lowest degree of solubility at all pH values and all storage periods, followed by RMGI and GI cement. Conclusions: The success of the restoration is dependent upon the choice of luting cement. The results of the studies reviewed show that all dental luting cements showed some degree of dissolution. Resin cement overall demonstrated the least amount of solubility, followed by RMGI and GI cement. Full article

Background and Objectives: This study aimed to investigate the effect of zinc phosphate (ZnP) cement, glass ionomer cement (GIC), and nano-integrated bio-ceramic (NIB) cement on mineralization when placed in contact with bone tissue-forming cells. Materials and Methods: ZnP cement, GIC, and NIB cement were divided into direct and indirect groups. A total of 72 cement pellets (24 pellets of each test sample) of 3 × 1 mm (width × height) were prepared using polytetrafluoroethylene molds. A total of 3 sample groups were demarcated using 96- cell well culture plates. In the control group, 24 wells were filled with mineralized osteoblasts and 1 µL of gingival crevicular fluid (GCF). In test group 1, to show a direct effect, 36 samples were plated with mineralized osteoblasts and 1 µL GCF for 24 h; the cells were directly exposed to cement pellets. A total of 36 samples were immersed in GCF for 24 h; later the supernatant was transferred to the mineralized osteoblasts to demonstrate an indirect effect in test group 2. To assess the mineralization, osteoblasts were stained with alizarin red and later observed under an inverted phase-contrast microscope. Data were analyzed using the statistical package for social sciences. An independent t-test compared the direct and indirect effects of the ZnP cement, GIC, NIB cement, and control groups on the mineralization of osteoblasts derived from hDPCs. Results: A statistically significant difference was observed between the ZnP cement, GIC, and NIB cement groups (p < 0.05). ZnP cement exhibited a moderate, NIB cement the least harmful effect, and GIC showed the most harmful effect on the mineralization of osteoblast cells. Conclusions: The biocompatibility of dental luting cements is an important aspect that clinicians should consider during their selection. Nano-integrated bio-ceramic cement showed the least negative effect on the mineralization of osteoblast cells which is beneficial for the cementation of cement-retained implant prostheses. However, further studies are needed to evaluate osteoblast and osteoclast activity in vivo. Full article

This study presents a scanning electron microscopy analysis of a failed PEEK retainer in an orthodontic patient. After 15 months of use, the patient reported a gap opening between teeth 41 and 42. The PEEK retainer was removed and sent for electron microscope analysis. To investigate the failure, scanning electron microscopy was employed to assess the microstructure and composition of the retainer at various magnifications. These findings suggest that the failure of the PEEK retainer was multifaceted, implicating factors such as material defects, manufacturing flaws, inadequate design, environmental factors, and patient-related factors. In conclusion, this scanning electron microscopy analysis offers valuable insights into the failure mechanisms of PEEK retainers in orthodontic applications. Further research is necessary to explore preventive strategies and optimize the design and fabrication of PEEK retainers, minimizing the occurrence of failures in orthodontic practice. Full article