Abstract

Oral cavity stem cells (OCSCs) have been the focus of intense scientific efforts due to their accessibility and stem cell properties. The present work aims to compare the different characteristics of 6 types of dental stem cells derived from the oral cavity: dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), bone marrow mesenchymal stem cells (BMSC), and gingival mesenchymal stem cells (GMSC). Using immunofluorescence and real-time polymerase chain reaction techniques, we analysed the cells for stem cell, differentiation, adhesion, and extracellular matrix markers; the ability to proliferate in vitro; and multilineage differentiation potential. Markers such as vimentin, CD44, alkaline phosphatase, CD146, CD271, CD49f, Oct 3/4, Sox 9, FGF7, nestin, and BMP4 showed significant differences in expression levels, highlighting the heterogeneity and unique characteristics of each cell type. At the same time, we confirmed that all cell types successfully differentiated into osteogenic, chondrogenic, or adipose lineages, with different readiness. In conclusion, our study reveals the distinct properties and potential applications of various dental-derived stem cells. These findings contribute to a deeper understanding of OCSCs and their significance in future clinical applications.

Introduction

Bone marrow mesenchymal stem cells (BMSCs) exhibit high proliferation ability and multilineage differentiation potential. They were the first mesenchymal stem cells (MSCs) to be described, isolated from adults’ bone marrow aspirate.1 They have been extensively researched in human and animal model systems using in vivo and in vitro cell cultures. Further, they have bridged the divide and are integrated into various trials for clinical applications, with mixed success.2,3 BMSCs are not easily accessible, and an invasive procedure is required. Therefore, further research in the field, aiming at identifying alternative stem cell sources, has led to the discovery of oral cavity stem cells (OCSCs).

Currently, several different types of OCSCs are well known, including dental pulp stem cells (DPSC), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSC), stem cells from the apical papilla (SCAP), dental follicle stem cells (DFSC), and gingival mesenchymal stem cells (GMSC).

Conclusions

This analysis of oral cavity–derived stem cells has exposed distinct and specific expression patterns of surface markers, ECM components, ECM remodelling enzymes, collagen genes, integrins, and differentiation potential. These findings may provide insights into the functional properties of these cell populations. Оur study aims to uncover the nuanced characteristics specific to each distinct cell type. Through experimentation and analysis, we anticipate to not only understand their individual functionalities but also gain deeper insights into their collective behaviour. Understanding both their shared characteristics and distinct attributes is an important step in using their regenerative potential in various tissue repair and regeneration contexts, thereby advancing the field of regenerative medicine and tissue engineering. By contributing meaningfully to the advancement of knowledge in regenerative medicine and tissue engineering, we aspire to pave the way for transformative breakthroughs in health care.

Highlights

Abstract

Keywords

1. Introduction

2. Materials and methods

3. Results

4. Discussion

5. Conclusions

Declaration of Competing Interest

Acknowledgement

References

Abstract

The objective of this research is to study the feasibility using nanomaterials to prevent and/or repair wear of teeth. Canine teeth have thin enamel prone to dental wear, causing pain, tooth loss, and infection. This research developed a new teeth repair agent based on the tribochemically active nanoparticles. The presence and properties of synthesized repair agents were evaluated after applying the repair agents by rubbing (simulated chewing) between extracted dog teeth. Polyether modified alpha‑zirconium phosphate (α-ZrP) nanoparticles form a strong and durable protective layer on a canine tooth’s enamel surface through chewing. The effectiveness of this protective film generation was enhanced by adding hydroxyapatite (HAp) nanoparticles into the repair agent. This protective film is up to 2 μm thick and has a hardness comparable to the enamel substrate. These results show that by chewing with the repair agent, the teeth are protected. The tomography result shows this repair agent also has the potential to mend cracks on the enamel surface. This research reports a novel approach to protect the wear of teeth. Nanoparticles promoted the generation of a protective film in situ during the chewing process. This nanomaterial can be the base of novel dental protective devices such as chewing toys or gums that preventing or reversing tooth wear and reducing the stress and cost of dental restoration operations.

1. Introduction
Tooth enamel is the hardest and most dense structure in the mammalian body. It serves to protect the interior of the tooth from the normal flora of the oral cavity and other harmful substances [1,2]. Although it is the hardest tissue in humans and animals [3–6], it can suffer damage from mechanical forces [7–12] and acidic solutions [13–16]. In dogs, the enamel layer is significantly thinner than in humans [17] and more prone to excessive wear and damage. This type of wear can result in dentin and pulp exposure causing significant oral pain, tooth loss, or periarticular and pulpal infections [18,19], leading to deterioration in quality of life and, in extreme cases, to be life threatening [13,20,21]. Recently, remineralization of damaged tooth enamel was presented as an alternative method to traditional dental operations [22–24]. These researchers utilized the bio-mineralization process that naturally presented in the dental environment [25–27]. Precursors to the nanoparticle hydroxyapatite were used to form the hard enamel tissue in vitro or in vivo [23,27]. Some examples of the precursors are casein phosphopeptide-stabilized amorphous calcium phosphate [28–30]; amelogenin with fluoride [31], and polydopamine with hydroxyapatite (HAP) [23]. Unlike traditional dental treatments, this method repaired teeth with materials that were almost identical to the teeth themselves. However, like the natural biomineralization process, using the remineralization method required significant time (>24 h) to take effect [22,23,27]. This is a major limitation to the clinical application of this approach.

Abstract

The aim of this study was to compare the 5-year outcome of full-arch mandibular fixed prosthetic rehabilitation using the All-on-4 concept in smoking and nonsmoking patients. This retrospective cohort study included 200 patients (n = 100 smokers, n = 100 nonsmokers), 119 women and 81 men, with an average age of 53.7 years, rehabilitated in immediate function with 800 implants. Implant cumulative survival rate estimation (Kaplan-Meier with log-rank test) and marginal bone resorption (MBR) at 5 years (Mann-Whitney test) were compared between both groups. Multivariable analysis was used to investigate potential risk indicators for MBR ≥ 2.8 mm at 5 years. Nine patients (4.5%) were lost to follow-up. Four patients lost eight implants, specifically one nonsmoking patient (n = 1 implant) and three smoking patients (n = 7 implants), resulting in a cumulative survival rate estimation of 99.0% and 96.9% for nonsmokers and smokers, respectively (P = 0.296). The average (standard deviation) MBR at 5 years was 1.68 mm (0.76 mm) and 1.98 mm (1.02 mm) for nonsmokers and smokers, respectively (P = 0.045). Smoking (odds ratio = 2.92) was the only risk indicator significantly associated with MBR ≥ 2.8 mm in multivariable analysis. Smoking should not be an absolute contraindication for rehabilitation of the edentulous mandible through the All-on-4 concept; however, smoking habits were significantly associated with MBR ≥ 2.8 mm.

Introduction

Smoking has long been causally associated with several cancers, heart disease, and chronic obstructive pulmonary disease and represents the leading cause of premature death and morbidity in the Western world (U.S. Department of Health and Human Services. The health consequences of smoking: a report of the surgeon general. 2004; 1). Cigarette smoking was previously reported to have a detrimental effect on early bone tissue response around dental implants, with marginal bone loss, gaps, and fibrous tissue surrounding the implants retrieved from smokers, together with a significant decrease in bone to implant contact percentage compared to nonsmokers (2).

In this paper we present the first results of a broad research line aiming a better understanding about dental implants as the number of procedures, successes and failures in Brazil and possible reasons of losses (from problems on diagnose to fabrication defects from different brands offered in the Brazilian market). One thing that is already evident is the lack of details of the performed elemental analysis of implants, not only in Brazil but also on the majority of reported analyses published on international journals dedicated to the field. There are already a significant number of reports about the composition of dental implants and its surfaces, but in general they have not performed tests enough to validate the results nor reported the procedure with sufficient details establishing their comprehensiveness, which is critical to enable a comparison between those results. One detected problem is the using of a non standard geometry in some equipment that require special shapes or dimension for the analysis. The other is the determination of the uncertainties to be associated to the results. Here we will perform a brief review of the dental implant history, of some problems found in the elemental analysis and will present two sets of measurements, one to investigate the consequences of using nonstandard geometries and another comparing elemental analyses made with different instruments.

INTRODUCTION

The first record of dental implants was 2000 BC, with the use of gold, platinum and porcelain. The Mayan civilization, among the many scientific advances it generated, was the first to use endosseous dental implants [1]. Over the years, various materials have been tested for dental implants, such as chromium-cobalt-molybdenum and iron-chromium-nickel alloys, stainless steel, and metals such as gold, platinum and silver. However, the clinical success obtained in the medium and long term for these materials was very low due to high peri-implant bone reabsorption [2]. The finding of the concept of osseointegration only occurred in 1965 by Brånemark in Sweden, leading a research group at the University of Gothenburg [3]. The original research of Brånemark was on the microcirculation of blood in rabbit tibias, with the assistance of a small titanium optical chamber, which was surgically inserted in the bone, to investigate the blood supply. After some time, when he tried to remove the chamber, Brånemark found it impossible because the chamber was integrated to the bone. It was thus evident that the integration between this metal and bone occurred perfectly, and there was no rejection [3]. The concept of osseointegration was then defined as the direct structural and functional connection between ordered, living bone and the surface of a loadcarrying implant. [4] Brånemark’s next step was to apply his discovery to oral rehabilitation, using titanium to built dental implants. Since then it was noticed that the clinical success of the implantology is directly related to the occurrence of the phenomenon of osseointegration and the type of material used [3].

Objective. To determine the translucency acceptability and perceptibility thresholds for dental resin composites using CIEDE2000 and CIELAB color difference formulas. Methods. A 30-observer panel performed perceptibility and acceptability judgments on 50 pairs of resin composites discs (diameter: 10mm; thickness: 1mm). Disc pair differences for the Translucency Parameter (TP) were calculated using both color difference formulas (TP00 ranged from 0.11 to 7.98, and TPab ranged from 0.01 to 12.79). A Takagi–Sugeno–Kang (TSK) Fuzzy Approximation was used as fitting procedure. From the resultant fitting curves, the 95% confidence intervals were estimated and the 50:50% translucency perceptibility and acceptability thresholds (TPT and TAT) were calculated. Differences between thresholds were statistically analyzed using Student t tests (˛ = 0.05). Results. CIEDE2000 50:50% TPT was 0.62 and TAT was 2.62. Corresponding CIELAB values were 1.33 and 4.43, respectively. Translucency perceptibility and acceptability thresholds were significantly different using both color difference formulas (p = 0.01 for TPT and p = 0.005 for TAT). CIEDE2000 color difference formula provided a better data fit than CIELAB formula. Significance. The visual translucency difference thresholds determined with CIEDE2000 color difference formula can serve as reference values in the selection of resin composites and evaluation of its clinical performance.

Introduction

The increased demand of patients for highly esthetic restorations has driven the development of dental materials with suitable optical properties. Translucency is an important property of dental tissues and materials. Thus, an appropri- ate determination and communication of optical properties should include translucency, in addition to more popular parameters such as: lightness (L*), a* and b* (CIELAB coordinates), hue angle (h◦) and chroma (C*). Translucency describes the ability of a material to transmit light [1]. The translucency parameter [2] (TP) has been used to assess the translucency of dental materials [3–7]. TP is defined as the CIELAB color difference (E*ab) for a material, at a particular thickness, on optical contact with ideal black and white backings [2]. Aiming to improve correction between perceived and computed color differences of CIELAB formula, the Commission Internationale de l’Éclairage (CIE) [8] recommended the use of CIEDE2000 color difference formula. However, at the moment in the majority of translucency studies in dental literature, the TP is still quantified using the CIELAB color space and its associated color formula (E*ab). Thus, determination of TP has shown differences in translucency of different composite resins depending of its shade [9],thickness [10]; matrix composition [11]; filler particle size and content [12,13] and type and amount of the opacifiers used [14]. Perceptibility difference threshold represents the lower perceptual limit, and it is widely applicable, mainly, to develop new color notation systems and their color difference metrics, to study discernible colors by the human visual system [15] and to understand the mechanisms of color vision [16]. However, in many practical situations, differences above the threshold (supra-threshold) are used, passing from perceptibility thresholds or “just noticeable differences” to higher differences, named “acceptable differences” or “tolerances.” The industrial interest on these differences is justified, on one hand, by the high cost required to maintain the industrial production below the limits of the visual threshold (perceptible threshold) and, on the other hand, by the need of maintaining the differences under an admissible limit. The complete absence of control (monitoring) should involves a lack of similarity in the production outcome, with negative implications on the overall quality of the product.

Abstract

Introduction: This study aimed to report a possible effect of the presence of an adjacent implant on the development of a vertical root fracture (VRF) in endodontically treated teeth. Methods: A series of 8 cases in 7 patients with teeth diagnosed with VRF after the placement of implants in the adjacent area is described and analyzed. In addition, a comprehensive literature search with strict inclusion and exclusion criteria was undertaken to identify additional clinical studies that assessed this clinical scenario. Results: The case series analysis revealed that the time from implant placement to the diagnosis of VRF was between 5 and 28 months (average = 11 months). The majority of cases occurred in female patients who received 2 or more implants. Six of the 7 patients were older than 40 years, with an average age of 54 years. The majority of teeth with VRF were premolar or mandibular molar teeth (6/8 teeth). All fractured teeth had been restored with a crown and had a post present, and the quality of the root canal filling was determined to be adequate. The systematic review revealed that implant-associated VRF has not been investigated or reported in the literature yet. Conclusions: Based on a systematic review of the literature, this case series, although limited in its extent, is the first clinical report of a possible serious adverse event of implantassociated VRF in adjacent endodontically treated teeth. Additional clinical studies are indicated to shed light on this potential phenomenon. (J Endod 2016;42:948–952)

Tooth replacement with an oral implant may be indicated because of tooth loss as a result of trauma, dental caries, periodontal disease, and in case of a congenitally missing tooth. The missing tooth space may be restored with an implant when it is surrounded with healthy teeth or with intact prosthetic reconstruction of the neighboring teeth (1).