24-Month clinical evaluation of cervical restorations bonded using radio-opaque universal adhesive compared to conventional universal adhesive in carious cervical lesions: A randomized clinical trial

The aim of the current study was to evaluate the clinical performance of the novel radio-opaque universal adhesive "Scotchbond™ Universal Adhesive Plus" compared to conventional universal adhesive "Single Bond Universal" over 24 months in cervical carious lesions. Fifty participants with cervical carious lesions were randomly allocated into two groups (n = 25); either Scotchbond™ Universal Plus Adhesive (intervention) or Single Bond™ Universal Adhesive (control). Restorations were assessed at baseline, 12 and 24 months using the modified USPHS criteria. Data analysis was conducted using MedCalc software, version 22 for Windows. Intergroup comparisons at each follow-up were performed using the Chi-Square test (p ≤ 0.05). Intragroup comparisons within each intervention were conducted using Cochran's Q test (p ≤ 0.016). After 24 months, all restorations in Scotchbond™ Universal Plus scored alpha, while in Single Bond™ Universal group, three restorations scored bravo after 24 months in marginal adaptation and discoloration. There was no statistically significant difference between both adhesives (p > 0.05) at all follow-up periods. Intragroup comparison within both adhesives has shown no statistically significant change across follow-up periods regarding all tested outcomes (p > 0.016) except for marginal adaptation within Single Bond Universal, where there was statistically significant difference (p = 0.005). Both adhesives exhibited satisfactory clinical performance in cervical restorations after 24-months. The present study emphasizes the clinical significance of using a new radio-opaque universal adhesive for restoring carious cervical lesions, providing radio-opacity, low viscosity, excellent handling, eliminating misinterpretation of MDP-based adhesive layer and generating reliable bonding performance to support long-term success in restorative dentistry.

Postoperative sensitivity of composites using novel Bacillus subtilis nanofortified adhesives: a triple-blind study

NANOTECHNOLOGY: is the art and science of dealing with nanoscale particles. This has transformed contemporary dental practices through myriad contributions to biomaterial science. Titanium dioxide nanoparticles procured from Bacillus subtilis, an eco-friendly and biogenic source, can significantly magnify the physiochemical attributes of dental materials. However, postoperative sensitivity is a major drawback of composite restorations. The incorporation of these nanoparticles into dental adhesives can greatly benefit clinical dentistry by resolving this issue. This trial aimed to evaluate the effectiveness of a novel titanium dioxide nanofortified adhesive on the postoperative sensitivity of composite restorations.

METHODS

This triple-blind, parallel-group randomized controlled trial was conducted at the Department of Operative Dentistry and Endodontics, School of Dentistry, Islamabad, from May 15, 2023, to November 25, 2023. Participants (n = 60) with Class I and II primary carious lesions with a minimum cavity depth of 3-5 mm were randomly assigned to two groups (n = 30). After obtaining informed consent, the restorative procedure was accomplished using a minimally invasive approach and etch-and-rinse adhesive strategy. In group A, a nanofortified adhesive was used for composite restoration, whereas in group B, an adhesive without nanoparticles was used. Postoperative sensitivity was evaluated using the Visual Analog Scale (VAS) score at follow-up periods: of one day, one week, two weeks and one month. A Chi-square test was used to compare postoperative sensitivity between the two groups. The level of significance was set at p < 0.05.

RESULTS

A noteworthy association was observed between sensitivity and the group variable at all four evaluation periods: after one day (p = 0.002), 1 week (p = 0.002), 2 weeks (p = 0.007) and one month. In conclusion, participants who underwent restorative intervention using titanium dioxide nanoreinforced adhesives reported a notable reduction in sensitivity at all time intervals. Hence, the occurrence and severity of postoperative sensitivity are significantly reduced using Bacillus subtilis-procured nanofortified adhesives as compared to conventional adhesives without nanoparticles.

TRIAL REGISTRATION

This trial was retrospectively registered at ClinicalTrials.gov (ID: NCT06242184) on 03/02/2024. All procedures involving human participants were performed in conformance with this protocol.

Effects of silane coupling treatment on the clinical performance of direct repaired resin-based composite (RBC) restorations with or without prior surface sandblasting: A randomized controlled trial

OBJECTIVE

To evaluate the effects, of using silane coupling agent within the procedures of repairing old composite restorations with or without sandblasting their surfaces, on the clinical performance of repaired composite restorations.

METHODS

The study involved repairing 130 Class I and II defective composite restorations. After recurrent caries removal, the repair process included etching with 37 % phosphoric acid, Adper Single Bond 2 application for bonding and Filtek Z250 composite for restoring all defects. The restoration surfaces were subjected to one of the following additional surface treatments within the repair process: Control: No additional treatment; the Silane-Adhesive treatment: A separate step involved the application of a silane coupling agent after acid etching; and the Sandblast-Silane-Adhesive treatment: included intra-oral sandblasting of old composite surfaces followed by silane application. Two calibrated examiners evaluated all repaired restorations according to a modified USPHS criteria after 6 months. Comparisons of the clinical performance between the treatment groups were made using Chi-square test, while responses to cold tests before and after repair treatment were made using Wilcoxon's Signed Rank's (α = 0.05).

RESULTS

Of 130 cases, only 116 cases turned up for evaluation. The primary reasons for composite repair were recurrent caries and anatomical deficiencies. No statistically significant differences were found between the groups for all clinical criteria (p > 0.05). The control group experienced one total and two partial retention losses.

CONCLUSIONS

The application of a silane coupling agent, with or without intra-oral sandblasting, demonstrated no improvement on the clinical performance of repaired posterior composites after 6-months.

CLINICAL SIGNIFICANCE

Surface treatment of defective composite restorations using silane with intra-oral sandblasting within their repair process offered marginal improvement in their clinical performance over conventional etching technique, but insignificantly so. Repair reduced exaggerated cold test responses and eliminated POS within 6-months. Repair reduces cold sensitivity and promotes restoration longevity. This clinical trial was registered at ClinicalTrials.gov with the registration number NCT06005571.

Teeth Restored with Bulk–Fill Composites and Conventional Resin Composites; Investigation of Stress Distribution and Fracture Lifespan on Enamel, Dentin, and Restorative Materials via Three-Dimensional Finite Element Analysis

Objectives: the aim of this study was to examine the stress distribution of enamel, dentin, and restorative materials in sound first molar teeth with restored cavities with conventional resin composites and bulk–fill composites, as well as to determine their fracture lifetimes by using the three-dimensional finite element stress analysis method. Materials and Methods: an extracted sound number 26 tooth was scanned with a dental tomography device and recorded. Images were obtained as dicom files, and these files were transferred to the Mimics 12.00 program. In this program, different masks were created for each tooth tissue, and the density thresholds were adjusted manually to create a three-dimensional image of the tooth, and these were converted to a STL file. The obtained STL files were transferred to the Geomagic Design X program, and some necessary adjustments, such as smoothing, were made, and STP files were created. Cavity preparation and adhesive material layers were created by transferring STP files to the Solidworks program. Finally, a FE model was created in the ABAQUS program, and stress distributions were analyzed. Results: when the bulk–fill composite and conventional resin composite materials were used in the restoration of the cavity, the structures that were exposed to the most stress as a result of occlusal forces on the tooth were enamel, dentin, restorative material, and adhesive material. When the bulk–fill composite material was used in restoration, while the restorative material had the longest fracture life as a result of stresses, the enamel tissue had the shortest fracture life. When the conventional resin composite material was used as the restorative material, it had the longest fracture life, followed by dentin and enamel. Conclusion: when the bulk–fill composite material was used instead of the conventional resin composite material in the cavity, the stress values on enamel, dentin, and adhesive material increased as a result of occlusal forces, while the amount of stress on the restorative material decreased. In the fracture analysis, when the bulk–fill composite material was used instead of the conventional resin composite material, a decrease in the number of cycles required for the fracture of enamel, dentin, and restorative materials was observed as a result of the forces generated in the oral cavity.

Evaluation of remineralizing effect of zinc-carbonate hydroxyapatite on the reduction of postrestorative sensitivity: A randomized controlled clinical trial

Background

The adhesive bonding ability of composite resins makes it unnecessary to remove tooth structure for retention, prevention, and convenience. However, postoperative sensitivity after placing composite restoration has been a significant problem experienced by clinicians.

Aim

The present randomized controlled trial was conducted to assess the role of dentin remineralization in the reduction of postoperative sensitivity after composite placement.

Materials and Methods

Eighty participants with occlusal carious teeth were randomly allocated to one of the four study groups, each having 20 participants, and are as follows: Group A with test group, Group A with control group, Group B with test group, and Group B with control group. Postoperative sensitivity was assessed using the Visual Analog Scale (VAS) and the United States Public Health Service (USPHS) criteria at different time intervals such as baseline, 1 week, 1 month, and 3 months. Data were analyzed using the Kruskal-Wallis ANOVA test, Mann-Whitney U-test, and Wilcoxon matched-pair test.

Results

All 80 participants were analyzed at the baseline, 1 week, 1 month, and the end of 3 months for the postoperative sensitivity using the VAS score and USPHS criteria. One restoration in Group A with control group reported mild sensitivity at the end of 1 week and one restoration in Group B with control group reported severe sensitivity at the end of 3 months, necessitating its replacement followed by root canal treatment. No relationship was reported between postoperative sensitivity and tooth type. There was no statistically significant difference in postoperative sensitivity in any of the treatment modalities.

Conclusion

Class I restoration using self-etch or selective-etch as well as with or without zinc-carbonate hydroxyapatite is a viable and predictable solution for the reduction of postoperative sensitivity if all the aspects of restorative techniques are considered precisely.

Mechanical and Thermal Stress Analysis of Cervical Resin Composite Restorations Containing Different Ratios of Zinc Oxide Nanoparticles: A 3D Finite Element Study

Due to an increase in prevalence of cervical lesions, it is important to use appropriate restorative materials to reduce the incidence of secondary lesions. Owing to having antibacterial properties, cervical composite restorations containing different ratios of Zinc Oxide nanoparticles (ZnO NPs) have been analyzed using the Finite Element method to determine the optimal incorporation ratio from mechanical and thermal perspectives. A numerical simulation is conducted for a mandibular first premolar with a cervical lesion (1.5 × 2 × 3 mm³) restored with composites containing 0 to 5% wt. ZnO NPs. Subsequently, the samples are exposed to different thermo-mechanical boundary conditions, and stress distributions at different margins are examined. The accumulated stress in the restoration part increases for the 1% wt. sample, whereas the higher percentage of ZnO NPs leads to the reduction of stress values. In terms of different loading conditions, the least and most stress values in the restoration part are observed in central loading and lingually oblique force, respectively. The change in the surface temperature is inversely correlated with the ratio of ZnO NPs. In conclusion, the composite containing 5% wt. ZnO NPs showed the most proper thermo-mechanical behavior among all samples.

Promoting mineralization at biological interfaces Ex vivo with novel amelotin-based bio-nano complexes

Conclusion

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AMTN/AMTN-Col functionalized HANP are potent mineral-promoting bio-nano complexes.

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AMTN/AMTN-Col coated HANP promote collagen mineralization.

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AMTN/AMTN-Col coated HANP enhance resin-dentin bond strength.

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AMTN/AMTN-Col coated HANP are potential candidates for clinical application.

Constructing an Antibiofouling and Mineralizing Bioactive Tooth Surface to Protect against Decay and Promote Self-Healing

Numerous methods have been investigated to manage dental caries, one of the top three diseases threatening human health as reported by the World Health Organization. An innovative strategy was proposed to prevent dental caries and achieve self-healing of the decayed tooth, and a novel bioactive peptide was designed and synthesized to construct an antibiofouling and mineralizing dual-bioactive tooth surface. Compared to its original endogenous peptide, the synthesized bioactive peptide showed statistically significantly higher binding affinity to the tooth surface, stronger suppression of demineralization, and a certain promotion of tooth remineralization. The abilities of the peptide to inhibit Streptococcus mutans (S. mutans) biofilm formation and S. mutans adhesion on the tooth surface were not affected after synthesis. Biocompatibility tests revealed the safety of the synthesized bioactive peptide. Interaction mechanisms between the synthesized bioactive peptide and tooth surface were also explained by molecular dynamic simulation analysis. In summary, the synthesized bioactive peptide could be applied safely to prevent dental caries and effectively induce in situ self-healing remineralization for treatment of the decayed tooth.