Enhancement of Orthodontic Tooth Movement by Local Administration of Biofunctional Molecules: A Comprehensive Systematic Review

Enhancement of orthodontic tooth movement (OTM) through local administration of biofunctional molecules has become increasingly significant, particularly for adult patients seeking esthetic and functional improvements. This comprehensive systematic review analyzes the efficacy of various biofunctional molecules in modulating OTM, focusing on the method of administration and its feasibility, especially considering the potential for topical application. A search across multiple databases yielded 36 original articles of experimental human and animal OTM models, which examined biofunctional molecules capable of interfering with the biochemical reactions that cause tooth movement during orthodontic therapy, accelerating the OTM rate through their influence on bone metabolism (Calcitriol, Prostaglandins, Recombinant human Relaxin, RANKL and RANKL expression plasmid, growth factors, PTH, osteocalcin, vitamin C and E, biocompatible reduced graphene oxide, exogenous thyroxine, sclerostin protein, a specific EP4 agonist (ONO-AE1-329), carrageenan, and herbal extracts). The results indicated a variable efficacy in accelerating OTM, with Calcitriol, Prostaglandins (PGE1 and PGE2), RANKL, growth factors, and PTH, among others, showing promising outcomes. PGE1, PGE2, and Calcitriol experiments had statistically significant outcomes in both human and animal studies and, while other molecules underwent only animal testing, they could be validated in the future for human use. Notably, only one of the animal studies explored topical administration, which also suggests a future research direction. This review concluded that while certain biofunctional molecules demonstrated potential for OTM enhancement, the evidence is not definitive. The development of suitable topical formulations for human use could offer a patient-friendly alternative to injections, emphasizing comfort and cost-effectiveness. Future research should focus on overcoming current methodological limitations and advancing translational research to confirm these biomolecules' efficacy and safety in clinical orthodontic practice.

A narrative review of the effects of vitamin D3 on orthodontic tooth movement: Focus on molecular and cellular mechanisms

Orthodontic tooth movement (OTM) is a critical process in dental alignment, driven by the application of calibrated orthodontic forces. This study delves into the intricate molecular and cellular mechanisms by which vitamin D3 influences OTM. Vitamin D3 is identified as a critical regulator in bone metabolism, enhancing osteoblast activity and bone formation while also modulating osteoclast quantity and RANKL expression, essential for the remodeling of the alveolar bone. The precise mechanisms through which vitamin D3 facilitates these processes are explored, highlighting its potential in accelerating bone remodeling and, consequently, tooth alignment. This comprehensive review underscores vitamin D3's anabolic impact on bone metabolism and its pivotal role in the synthesis and mineralization processes governed by osteoblasts. The findings illuminate vitamin D3's promise in augmenting orthodontic therapy, suggesting its utility in improving treatment efficiency and reducing duration. However, the need for further research into the optimal application of vitamin D3 in orthodontics is emphasized, particularly concerning dosage, timing, and delivery methods.

Irisin reduces orthodontic tooth movement in rats by promoting the osteogenic potential in the periodontal ligament

OBJECTIVES

Positive effects of irisin on osteogenic differentiation of periodontal ligament (PDL) cells have been identified previously, this study aims to examine its effect on orthodontic tooth movement (OTM) in vivo.

MATERIALS AND METHODS

The maxillary right first molars of male Wistar rats (n = 21) were moved mesially for 14 days, with submucosal injection of two dosages of irisin (0.1 or 1 μg) or phosphate-buffered saline (control) every third day. OTM was recorded by feeler gauge and micro-computed tomography (μCT). Alveolar bone and root volume were analysed using μCT, and plasma irisin levels by ELISA. Histological characteristics of PDL tissues were examined, and the expression of collagen type I, periostin, osteocalcin (OCN), von Willebrand factor (vWF) and fibronectin type III domain-containing protein 5 (FNDC5) in PDL was evaluated by immunofluorescence staining.

RESULTS

Repeated 1 μg irisin injections suppressed OTM on days 6, 9, and 12. No significant differences were observed in OTM in the 0.1 μg irisin group, or in bone morphometric parameters, root volume or plasma irisin, compared to control. Resorption lacunae and hyalinization were found at the PDL-bone interface on the compression side in the control, whereas they were scarce after irisin administration. The expression of collagen type I, periostin, OCN, vWF, and FNDC5 in PDL was enhanced by irisin administration.

LIMITATIONS

The feeler gauge method may overestimate OTM.

CONCLUSIONS

Submucosal irisin injection reduced OTM by enhancing osteogenic potential of PDL, and this effect was more significant on the compression side.

Functional Biomaterials for Local Control of Orthodontic Tooth Movement

Orthodontic tooth movement (OTM) occurs with the application of a controlled mechanical force and results in coordinated tissue resorption and formation in the surrounding bone and periodontal ligament. The turnover processes of the periodontal and bone tissue are associated with specific signaling factors, such as Receptor Activator of Nuclear factor Kappa-β Ligand (RANKL), osteoprotegerin, runt-related transcription factor 2 (RUNX2), etc., which can be regulated by different biomaterials, promoting or inhibiting bone remodeling during OTM. Different bone substitutes or bone regeneration materials have also been applied to repair alveolar bone defects followed by orthodontic treatment. Those bioengineered bone graft materials also change the local environment that may or may not affect OTM. This article aims to review functional biomaterials that were applied locally to accelerate OTM for a shorter duration of orthodontic treatment or impede OTM for retention purposes, as well as various alveolar bone graft materials which may affect OTM. This review article summarizes various types of biomaterials that can be locally applied to affect the process of OTM, along with their potential mechanisms of action and side effects. The functionalization of biomaterials can improve the solubility or intake of biomolecules, leading to better outcomes in terms of increasing or decreasing the speed of OTM. The ideal timing for initiating OTM is generally considered to be 8 weeks post-grafting. However, more evidence is needed from human studies to fully understand the effects of these biomaterials, including any potential adverse effects.

Systematic review of biological therapy to accelerate orthodontic tooth movement in animals: Translational approach

OBJECTIVES

To systematically review and evaluate what is known regarding contemporary biological therapy capable of accelerating orthodontic tooth movement (OTM) in animal model.

MATERIALS AND METHODS

MedLine, Scopus, Web of Science and OpenGrey were searched without restrictions until June 2019. Following study retrieval and selection, relevant data was extracted using a standardized table. Risk of bias (RoB) assessment was performed using the Systematic Review Centre for Laboratory Animal Experimentation (SYRCLE) tool.

RESULTS

Fifty-one animal studies were included. Two biological therapies were identified as capable of accelerating the OTM: chemical methods (49 studies) and gene therapy (2 studies). The main substances that increased the OTM rate were cytokines (13 studies), followed by growth factors (6 studies) and hormones (5 studies). Most studies were assessed to be at unclear or high RoB. The application protocols, measurement and reporting of outcomes varied widely and methodologies were not adequately reported.

CONCLUSIONS

Although biological therapies to accelerate OTM have been widely tested and effective in preclinical studies, the validity of the evidence is flawed to support translational of these results. There is a need for well-designed experimental studies to translate these methods for clinical field.

Wound healing related agents: Ongoing research and perspectives

Wound healing response plays a central part in chronic inflammation, affecting millions of people worldwide. It is a dynamic process that can lead to fibrosis, if tissue damage is irreversible and wound resolution is not attained. It is clear that there is a tight interconnection among wound healing, fibrosis and a variety of chronic disease conditions, demonstrating the heterogeneity of this pathology. Based on our further understanding of the cellular and molecular mechanisms underpinning tissue repair, new therapeutic approaches have recently been developed that target different aspects of the wound healing process and fibrosis. Nevertheless, several issues still need to be taken into consideration when designing modern wound healing drug delivery formulations. In this review, we highlight novel pharmacological agents that hold promise for targeting wound repair and fibrosis. We also focus on drug-delivery systems that may enhance current and future therapies.

Liposomal systems as carriers for bioactive compounds

Since the revolutionary discovery that phospholipids can form closed bilayered structures in aqueous systems, the study of liposomes has become a very interesting area of research. The versatility and amazing biocompatibility of liposomes has resulted in their wide-spread use in many scientific fields, and many of their applications, especially in medicine, have yielded breakthroughs in recent decades. Specifically, their easy preparation and various structural aspects have given rise to broadly usable methodologies to internalize different compounds, with either lipophilic or hydrophilic properties. The study of compounds with potential biotechnological application(s) is generally related to evaluation and risk assessment of the possible cytotoxic or therapeutic effects of the compound under study. In most cases, undesirable side-effects are associated with an interaction of the liposome with the cell membrane and/or its absorption and subsequent interaction with a cellular biomolecule. Liposomal carrier systems have an unprecedented potential for delivering bioactive substances to specific molecular targets due to their biocompatibility, biodegradability and low toxicity. Liposomes are therefore considered to be an invaluable asset in applied biotechnology studies due to their potential for interaction with both hydrophilic and lipophilic compounds.

Effect of PDGF-BB, IGF-I growth factors and their combination carried by liposomes in tooth socket healing

This work evaluated the bone-forming potential of the platelet-derived growth factor isoform BB (PDGF-BB), insulin-like growth factor I (IGF-I), and mixed PDGF-BB/IGF-I delivered in liposomes compared with phosphate buffered saline (PBS), in the healing process of rat tooth sockets. One hundred and twelve Wistar rats were randomized into 7 groups of 16 animals each and were evaluated at 3, 7, 14 and 21 days after extraction of the maxillary second molars. The left sockets were treated with PBS (P), empty liposome (L), IGF-I in PBS (IP), IGF-I in liposome (IL), PDGF-BB in PBS (PDP), PDGF-BB in liposome (PDL) and both growth factors (GFs) together within liposomes (PDIL). The right sockets were filled with blood clot (BC). Histological and histomorphometric analyses were used to evaluate the formation of new bone and blood vessels. Immunohistochemistry was performed to evaluate the expression of osteocalcin and vascular endothelial growth factor (VEGF) during bone repair. Data were tested statistically using a Tukey's test according to a Dunn's analysis and Mann-Whitney U test followed by Kruskal-Wallis one-way analysis. Results were considered significant when p<0.05. A significantly higher percentage of bone trabeculae and a higher number of blood vessels were observed in the IL, PDL and PDIL groups (p<0.05). However, these GF-liposome groups had statistically similar results. Immunohistochemical assays first detected osteocalcin and VEGF expression at 3 days followed by a peak at 7 days. Lower immunoreactivity levels were observed in the BC, L, P, IP and PDP groups compared with the IL, PDL and PDIL groups (p<0.05). The results suggest that GFs carried by liposomes, either in isolated or mixed forms, enhanced the healing process in rat tooth sockets. The differential expression of the osteogenic markers VEGF and osteocalcin in the early phases of bone healing support these findings.

Proteoliposomes in nanobiotechnology

Proteoliposomes are systems that mimic lipid membranes (liposomes) to which a protein has been incorporated or inserted. During the last decade, these systems have gained prominence as tools for biophysical studies on lipid-protein interactions as well as for their biotechnological applications. Proteoliposomes have a major advantage when compared with natural membrane systems, since they can be obtained with a smaller number of lipidic (and protein) components, facilitating the design and interpretation of certain experiments. However, they have the disadvantage of requiring methodological standardization for incorporation of each specific protein, and the need to verify that the reconstitution procedure has yielded the correct orientation of the protein in the proteoliposome system with recovery of its functional activity. In this review, we chose two proteins under study in our laboratory to exemplify the steps necessary for the standardization of the reconstitution of membrane proteins in liposome systems: (1) alkaline phosphatase, a protein with a glycosylphosphatidylinositol anchor, and (2) Na,K-ATPase, an integral membrane protein. In these examples, we focus on the production of the specific proteoliposomes, as well as on their biochemical and biophysical characterization, with emphasis on studies of lipid-protein interactions. We conclude the chapter by highlighting current prospects of this technology for biotechnological applications, including the construction of nanosensors and of a multi-protein nanovesicular biomimetic to study the processes of initiation of skeletal mineralization.

Local delivery of EGF-liposome mediated bone modeling in orthodontic tooth movement by increasing RANKL expression

AIMS

It has long been demonstrated that epidermal growth factor (EGF) has catabolic effects on bone. Thus, we examined the role of EGF in regulating mechanically induced bone modeling in a rat model of orthodontic tooth movement.

MAIN METHODS

The maxillary first molars of rats were moved mesially using an orthodontic appliance attached to the maxillary incisor teeth. Rats were randomly divided into 4 groups: (G1) administration of PBS (phosphate buffer saline) solution (n=24); (G2) administration of empty liposomes (n=24); (G3) administration 20ng of EGF solution (n=24); and (G4) 20ng of EGF-liposomes solution (n=24). Each solution was injected in the mucosa of the left first molar adjacent to the appliance. At days 5, 10, 14 and 21 after drug administration, 6 animals of each group were sacrificed. Histomorphometric analysis was used to quantify osteoclasts (Tartrate-resistant acid phosphatase (TRAP)+cells) and tooth movement. Using immunohistochemistry assay we evaluated the RANKL (receptor activator of nuclear factor kappaB ligand) and epidermal growth factor receptor (EGFR) expression.

KEY FINDINGS

The EGF-liposome administration showed an increased tooth movement and osteoclast numbers compared to controls (p<0.05). This was correlated with intense RANKL expression. Both osteoblasts and osteoclasts expressed EGFR.

SIGNIFICANCE

Local delivery of EGF-liposome stimulates osteoclastogenesis and tooth movement.

Nanoparticulate systems for growth factor delivery

The field of nanotechnology, which aims to control and utilize matter generally in 1-100 nm range, has been at the forefront of pharmaceutical development. Nanoparticulate delivery systems, with their potential to control drug release profiles, prolonging the presence of drugs in circulation, and to target drugs to a specific site, hold tremendous promise as delivery strategies for therapeutics. Growth factors are endogenous polypeptides that initiate intracellular signals to regulate cellular activities, such as proliferation, migration and differentiation. With improved understanding of their roles in physiopathology and expansion of their availability through recombinant technologies, growth factors are becoming leading therapeutic candidates for tissue engineering approaches. However, the outcome of growth factor therapeutics largely depends on the mode of their delivery due to their rapid degradation in vivo, and non-specific distribution after systemic administration. In order to overcome these impediments, nanoparticulate delivery systems are being harnessed for spatiotemporal controlled delivery of growth factors. This review presents recent advances and some disadvantages of various nanoparticulate systems designed for effective intact growth factor delivery. The therapeutic applications of growth factors delivered by such systems are reviewed, especially for bone, skin and nerve regeneration as well as angiogenesis. Finally, future challenges and directions in the field are presented in addition to the current limitations.