Journal of Functional Biomaterials

Research

17 pages, 6300 KiB

Open AccessArticle

Finite Element Simulation of Biomechanical Effects on Periodontal Ligaments During Maxillary Arch Expansion with Thermoformed Aligners

by Gustavo A. Rojas, Jose Isidro García-Melo and Juan S. Aristizábal

J. Funct. Biomater. 2025, 16(4), 143; https://doi.org/10.3390/jfb16040143 - 17 Apr 2025

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Abstract

Purpose: This paper investigates the biomechanical effect of thermoformed aligners equipped with complementary biomechanical attachments (CBAs) on periodontal ligaments (PDLs) during the expansion process of the maxillary arch. The analysis was conducted using advanced simulations based on the finite element method (FEM). Methods: [...] Read more.

Purpose: This paper investigates the biomechanical effect of thermoformed aligners equipped with complementary biomechanical attachments (CBAs) on periodontal ligaments (PDLs) during the expansion process of the maxillary arch. The analysis was conducted using advanced simulations based on the finite element method (FEM). Methods: High-resolution 3D CAD models were created for four tooth types: canine, first premolar, second premolar, and first molar. Additional 3D models were developed for aligners, CBAs, and PDLs. These were integrated into a comprehensive FEM model to simulate clinical rehabilitation scenarios. Validation was achieved through comparative analysis with empirical medical data. Results: The FEM simulations revealed the following: for canine, the displacement was 0.134 mm with a maximum stress of 4.822 KPa in the amelocemental junction. For the first premolar, the displacement was 0.132 mm at a maximum stress of 3.273 KPa in the amelocemental junction. The second premolar had a displacement of 0.129 mm and a stress of 1.358 KPa at 1 mm from the amelocemental junction; and first molar had a displacement of 0.124 mm and a maximum stress of 2.440 KPa. Conclusions: The inclusion of CBAs significantly reduced tooth tipping during maxillary arch expansion. Among the models tested, the vestibular CBA demonstrated superior performance, delivering optimal tooth movement when combined with thermoformed aligners. Significance: FEM techniques provide a robust and cost-effective alternative to in vivo experimentation, offering precise and reliable insights into the biomechanical efficacy of CBAs in thermoformed aligners. This approach minimizes experimental variability and accelerates the evaluation of innovative orthodontic configurations. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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10 pages, 677 KiB

Open AccessArticle

An Assessment of the Micro-Tensile Bond Strength of Composites for Indirect Restoration to Enamel and Dentin

by Viktoria Petrova, Janet Kirilova and Sevda Yantcheva

J. Funct. Biomater. 2025, 16(4), 138; https://doi.org/10.3390/jfb16040138 - 12 Apr 2025

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Abstract

This study aimed to evaluate the micro-tensile bond strength (µTBS) of two types of composites for indirect restoration, luted to enamel and dentin with self-adhesive cement. Moreover, it aimed to evaluate the impact of thermocycling on bond strength. Sixteen flat enamel and dentin [...] Read more.

This study aimed to evaluate the micro-tensile bond strength (µTBS) of two types of composites for indirect restoration, luted to enamel and dentin with self-adhesive cement. Moreover, it aimed to evaluate the impact of thermocycling on bond strength. Sixteen flat enamel and dentin surfaces of human molars were cemented to equal flat specimens of the laboratory composite Signum ceramis and the CAD/CAM block Cerasmart. Half of the specimens of the group underwent thermocycling. After that, the samples were cut into 80 beams for µTBS analysis. The data were analyzed using Levene’s test and the independent sample t-test. The micro-tensile bond strength tests revealed that thermocycling significantly reduced the adhesive bond. Dentin bonds better to conventional laboratory composites. Enamel bonds are better than composite blocks for milling. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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11 pages, 1390 KiB

Open AccessArticle

Promoting Dentin Bridge Formation Through N-Acetyl-L-Cysteine Application in Rat Molar Pulpotomy: An Experimental Study

by Kota Takagi, Koichi Nakamura, Yoshitaka Yoshimura and Yasutaka Yawaka

J. Funct. Biomater. 2025, 16(4), 117; https://doi.org/10.3390/jfb16040117 - 27 Mar 2025

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Abstract

Pulpotomy is performed when tooth decay reaches the dental pulp or when the crown is fractured due to trauma. Mineral trioxide aggregate (MTA) is commonly used in pulpotomy, but its prognosis can be variable. N-acetyl-L-cysteine (NAC), an antioxidant amino acid, has garnered attention [...] Read more.

Pulpotomy is performed when tooth decay reaches the dental pulp or when the crown is fractured due to trauma. Mineral trioxide aggregate (MTA) is commonly used in pulpotomy, but its prognosis can be variable. N-acetyl-L-cysteine (NAC), an antioxidant amino acid, has garnered attention due to its potential benefits. This study aimed to investigate the effects of MTA and NAC on pulpotomy outcomes. We used Sprague Dawley rat maxillary molars to perform pulpotomy and employed Superbond C&B, MTA, and MTA mixed with NAC (MTA–NAC) for pulp capping. We obtained tissue sections 3 and 7 days postpulpotomy, conducting histological analysis by examining the morphology of pulp tissue and assessing dentin sialophosphoprotein (DSPP) and osteopontin expression levels. At 3 days postpulpotomy, MTA and MTA–NAC reduced the inflammatory response. At 7 days postpulpotomy, dentin bridge formation was observed following MTA–NAC application, and although MTA resulted in DSPP- and osteopontin-positive areas, these areas were more extensive following MTA–NAC application. Given that adding NAC to MTA enhanced dentin bridge formation, MTA–NAC appears to be a superior option for pulp capping. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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16 pages, 9752 KiB

Open AccessArticle

Hydroxyapatite Dental Inserts for Tooth Restoration: Stress and Displacement Analysis

by Maja Lezaja Zebic, Aleksandar Bodic, Djordje Veljovic, Tamara Matic, Jelena Carkic and Vladimir Milovanovic

J. Funct. Biomater. 2025, 16(3), 75; https://doi.org/10.3390/jfb16030075 - 20 Feb 2025

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Abstract

Hydroxyapatite (HAP) inserts minimize restoration contraction by constituting a major part of the restoration; however, their effect on the relaxation of tooth tissues has not been previously tested. Finite element analysis was employed to estimate stress and displacement when HAP inserts with a [...] Read more.

Hydroxyapatite (HAP) inserts minimize restoration contraction by constituting a major part of the restoration; however, their effect on the relaxation of tooth tissues has not been previously tested. Finite element analysis was employed to estimate stress and displacement when HAP inserts with a thickness of 1.7 mm or 4.7 mm and a diameter of 4.7 mm were used to substitute for dentin. The volumetric contraction of the composite during polymerization, simulated through steady-state heat transfer analysis, yielded a contraction rate of 3.7%. Descriptive statistics revealed that the incorporation of HAP inserts reduced the displacement of dentin, enamel, and restoration caused by contraction by 44.4% to 66.7%, while maximal stress was reduced by 8.1% to 52%. Subsequent loading on the occlusal tooth surface showed that displacement values decreased by 12.1% to 33.3%, while maximum von Mises stress in enamel decreased by 32.8% to 40.6% with the use of HAP inserts. Although the maximum stress values in dentin were not significantly decreased (3% to 8.8%), the stress located at the bottom of the cavity was notably reduced, particularly in deep cavities at root canal entrances. The use of HAP inserts in restorative dentistry provides benefits for the preservation of prepared teeth, especially in preventing irreparable vertical root fractures of endodontically treated teeth. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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9 pages, 1217 KiB

Open AccessArticle

Dental Implant Survival Rates: Comprehensive Insights from a Large-Scale Electronic Dental Registry

by Guy Tobias, Tali Chackartchi, Doron Haim, Jonathan Mann and Mordechai Findler

J. Funct. Biomater. 2025, 16(2), 60; https://doi.org/10.3390/jfb16020060 - 11 Feb 2025

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Abstract

Background: This descriptive study aimed to assess the survival rates and outcomes of dental implants in one of the four national HMOs in Israel. Data are provided for the period from 1 January 2014 to 31 December 2022. Materials and Methods: This retrospective [...] Read more.

Background: This descriptive study aimed to assess the survival rates and outcomes of dental implants in one of the four national HMOs in Israel. Data are provided for the period from 1 January 2014 to 31 December 2022. Materials and Methods: This retrospective analysis utilized electronic medical records of patients who underwent dental implant placement during the specified period. Statistical analyses included chi-squared tests, Student’s t-tests, and generalized estimating equation (GEE) analyses to identify potential risk factors associated with early and late implant failures. Results: A total of 158,824 dental implants were placed in 53,874 patients. The overall implant failure rate was 2.21%, while the early failure rate during the osseointegration phase—before prosthetic reconstruction—was 1.56%. Significant associations with implant failure were observed for male patients (2.53% failure rate), implants in the maxillary molar region (3%), and the central incisor region (3.37%), approximately double the failure rates seen in other implant sites (p < 0.001). Conclusions: This extensive data analysis demonstrates a low overall failure rate for dental implants. The highest failure incidence occurred within the first year post-implantation, declining in subsequent years irrespective of rehabilitation status. Early failure risk factors differ based on various factors and should be carefully integrated into presurgical planning. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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13 pages, 1634 KiB

Open AccessArticle

Effect of Mechanical Surface Treatment on Shear Bond Strength of Orthodontic Brackets to 3D Printed and Milled CAD/CAM Provisional Materials: An In Vitro Study

by Abdulaziz A. Alzaid, Khalid K. Alanazi, Lulu A. Alyahya, Maha N. Alharbi, Hatem Alqarni, Mohammed Alsaloum, Hayam A. Alfallaj and Ghada S. Alotaibi

J. Funct. Biomater. 2024, 15(12), 358; https://doi.org/10.3390/jfb15120358 - 25 Nov 2024

Cited by 1 | Viewed by 1399

Abstract

The aim of the study is to assess the impact of mechanical surface treatments on the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensional (3D) printed and milled CAD/CAM provisional materials. Sixty cylindrical samples were fabricated for each provisional material. Samples [...] Read more.

The aim of the study is to assess the impact of mechanical surface treatments on the shear bond strength (SBS) of orthodontic brackets bonded to three-dimensional (3D) printed and milled CAD/CAM provisional materials. Sixty cylindrical samples were fabricated for each provisional material. Samples were treated with one of the following surface treatments: aluminum oxide airborne particle abrasion, diamond bur rotary instrument roughening, and phosphoric acid etching (control). Stainless steel brackets were bonded to the samples, and then SBS was tested using a universal testing machine. SEM and digital microscopy were utilized to examine the bonding interface and the failure modes. Two-way ANOVA, one-way ANOVA, Tukey’s HSD, and independent sample t-tests were used for statistical analysis. Results revealed significant differences in SBS between 3D printed and milled samples and significant differences in SBS among most surface treatments, with rotary instrument roughening resulting in the highest values for 3D printed, while airborne particle abrasion leading for milled samples. Digital microscopy indicated that more adhesive remained on 3D-printed samples. SEM analysis revealed varying surface roughness across treatments. Based on the findings of this study, it can be concluded that different surface treatments improve the bonding of orthodontic brackets to provisional crowns. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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11 pages, 2744 KiB

Open AccessEditor’s ChoiceArticle

Enhancing the Biological Properties of Organic–Inorganic Hybrid Calcium Silicate Cements: An In Vitro Study

by Minji Choi, Jiyoung Kwon, Ji-Hyun Jang, Duck-Su Kim and Hyun-Jung Kim

J. Funct. Biomater. 2024, 15(11), 337; https://doi.org/10.3390/jfb15110337 - 10 Nov 2024

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Abstract

(1) Background: This study aimed to enhance the biological properties of hydraulic calcium silicate cements (HCSCs) by incorporating organic and inorganic components, specifically elastin-like polypeptides (ELPs) and bioactive glass (BAG). We focused on the effects of these composites on the viability, migration, and [...] Read more.

(1) Background: This study aimed to enhance the biological properties of hydraulic calcium silicate cements (HCSCs) by incorporating organic and inorganic components, specifically elastin-like polypeptides (ELPs) and bioactive glass (BAG). We focused on the effects of these composites on the viability, migration, and osteogenic differentiation of human periodontal ligament fibroblasts (hPDLFs). (2) Methods: Proroot MTA was supplemented with 1–5 wt% 63S BAG and 10 wt% ELP. The experimental groups contained various combinations of HSCS with ELP and BAG. Cell viability was assessed using an MTT assay, cell migration was evaluated using wound healing and transwell assays, and osteogenic activity was determined through Alizarin Red S staining and a gene expression analysis of osteogenic markers (ALP, RUNX-2, OCN, and Col1A2). (3) Results: The combination of ELP and BAG significantly enhanced the viability of hPDLFs with an optimal BAG concentration of 1–4%. Cell migration assays demonstrated faster migration rates in groups with 2–4% BAG and ELP incorporation. Osteogenic activity was the highest with 2–3% BAG incorporation with ELP, as evidenced by intense Alizarin Red S staining and the upregulation of osteogenic differentiation markers. (4) Conclusions: The incorporation of ELP (organic) and BAG (inorganic) into HCSC significantly enhances the viability, migration, and osteogenic differentiation of hPDLFs. These findings suggest that composite HCSC might support healing in destructed bone lesions in endodontics. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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17 pages, 8184 KiB

Open AccessArticle

Mechanical Assessment of Denture Polymers Processing Technologies

by Cristina Modiga, Andreea Stoia, Marius Traian Leretter, Ana Codruţa Chiş, Andreea-Violeta Ardelean, Edward-Ronald Azar, Gabriel Kapor, Daniela-Maria Pop, Mihai Romînu, Cosmin Sinescu, Meda-Lavinia Negruţiu and Emanuela-Lidia Petrescu

J. Funct. Biomater. 2024, 15(8), 234; https://doi.org/10.3390/jfb15080234 - 21 Aug 2024

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Abstract

Background: Removable prostheses have seen a fundamental change recently because of advances in polymer materials, allowing improved durability and performance. Despite these advancements, notable differences still occur amongst various polymer materials and processing technologies, requiring a thorough grasp of their mechanical, physical, and [...] Read more.

Background: Removable prostheses have seen a fundamental change recently because of advances in polymer materials, allowing improved durability and performance. Despite these advancements, notable differences still occur amongst various polymer materials and processing technologies, requiring a thorough grasp of their mechanical, physical, and therapeutic implications. The compressive strength of dentures manufactured using various technologies will be investigated. Methods: Traditional, injection molding, and additive and subtractive CAD/CAM processing techniques, all utilizing Polymethyl methacrylate (PMMA) as the main material, were used to construct complete dentures. The specimens underwent a compressive mechanical test, which reveals the differences in compressive strength. Results: All the specimens broke under the influence of a certain force, rather than yielding through flow, as is characteristic for plastic materials. For each specimen, the maximum force (N) was recorded, as well as the breaking energy. The mean force required to break the dentures for each processing technology is as follows: 4.54 kN for traditional packing-press technique, 17.92 kN for the injection molding technique, 1.51 kN for the additive CAD/CAM dentures, and 5.9 kN for the subtractive CAD/CAM dentures. Conclusions: The best results were obtained in the case of the thermoplastic injection system and the worst results were recorded in the case of 3D printed samples. Another important aspect depicted is the standard deviation for each group, which reveal a relatively unstable property for the thermoplastic injected dentures. Good results here in terms of absolute property and stability of the property can be conferred to CAD/CAM milled group. Full article

(This article belongs to the Special Issue Biomechanical Studies and Biomaterials in Dentistry)

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