Metabolic factors are essential for developmental biology of an organism. In plants, roots fulfill important functions, in part due to the development of specific epidermal cells, called hair cells that form root hairs (RHs) responsible for water and mineral uptake. RH development consists in (a) patterning processes involved in formation of hair and non-hair cells developed from trichoblasts and atrichoblasts; (b) RH initiation; and (c) apical (tip) growth of the RH. Here we review how these processes depend on pools of different amino acids and what is known about RH phenotypes of mutants disrupted in amino acid biosynthesis. This analysis shows that some amino acids, particularly aromatic ones, are required for RH apical (tip) growth, and that not much is known about the role of amino acids at earlier stages of RH formation. We also address the role of amino acids in rhizosphere, inhibitory and stimulating effects of amino acids on RH growth, amino acids as N source in plant nutrition, and amino acid transporters and their expression in the RHs. Amino acids form conjugates with auxin, a hormone essential for RH growth, and respective genes are overviewed. Finally, we outline missing links and envision some perspectives in the field.

OBJECTIVE: To determine the survival of intentional autotransplantation of developing teeth.
METHODS: An electronic search was carried out in the MEDLINE database, Web of Science, and Cochrane Library. The criteria used are the ones described in the PRISMA Declaration. The following MeSH terms were used: (\"tooth\" [MeSH Terms] OR \"tooth\" [All Fields]) AND (\"transplantation, autologous\" [MeSH Terms] OR (\"transplantation\" [All Fields] AND \"autologous\" [All Fields]) OR \"autologous transplantation\" [All Fields] OR \"autotransplantation\" [All Fields]) AND (\"humans\" [MeSH Terms]. Randomised clinical trials and prospective and retrospective clinical studies were included.
RESULTS: The meta-analytic study of overall survival included a total of 14 studies, yielding an overall survival rate of 97.9%. In studies with 1-year follow-ups, survival was 98%. The resulting 2-year follow-up rate was 97%, while the 5- and 10-year survival rates were 95.9% and 96.9%, respectively.
CONCLUSIONS: The autotransplantation technique performed in a single-phase and on teeth that have not completed their development is a predictable technique, with a described survival rate at a 2-year follow-up of more than 97%.
CONCLUSIONS: The technique of dental autotransplantation is considered an important resource for the resolution and rehabilitation of tooth loss in patients, especially in those who are still in a growth period. Moreover, this technique has a low complication rate and a 10-year survival rate of 96.9%. It should therefore be considered a safe and reliable procedure.

(1) Background: Treating dental luxation injuries is challenging for the clinician. Dental luxations account for 18-33% of injuries to permanent teeth and can be addressed using different therapeutic approaches. The present work was conducted with two aims: (i) to evaluate, through a scoping review, current knowledge of the orthodontic methods (repositioning and stabilization splinting) that can be used at the time of the trauma, and (ii) to investigate the frequency and type of pulp consequences arising after these traumatic injuries. (2) Methods: The literature search was conducted in the period June 2020-December 2020 using the PubMed/MEDLINE, SCOPUS and Web of Science databases. The research questions were formulated according to the PICO (Population, Intervention, Comparison, Outcomes) method and considered the following aspects: type of luxation injury and stage of root development; use of orthodontic repositioning and splinting techniques; frequency and type of pulp consequences; and compliance of treatments with international guidelines. (3) Results: The initial screening of the databases, using the selected search keywords, yielded a total of 587 articles, just 8 fully met the inclusion criteria. Closer analysis of these 8 publications revealed that they would not produce clear meta-analytical data. This made it necessary to limit the data collected to the following six items: number and type of injuries, initial therapeutic intervention, duration of follow-up, number, and type of different pulp consequences. (4) Conclusions: While orthodontic techniques are commonly used to treat dental intrusions, in the case of extrusive and lateral luxation injuries, they are less frequently used and the orthodontic approach is generally confined to the stabilization phase. Among the various possible pulp consequences, many authors consider only pulp canal obliteration (PCO) and pulp necrosis (PN), often tending to overlook physiological healing (pulp survival) and the possible development of PN after PCO. There is therefore a clear need for new, high-quality clinical studies of this topic based on systematic and standardized data collection.

BACKGROUND: The purposes of this review were to appraise the level of evidence of the existing regenerative endodontic therapy (RET) publications, perform a meta-analysis on the survival and healing rates of necrotic immature permanent teeth treated with RET, and run a meta-analysis on the quantitative assessment of the root development of those teeth.
METHODS: Electronic searches were performed in Web of Science, PubMed, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Cochrane Library databases. Two authors independently screened the titles and abstracts for eligibility. The analyses were performed on the clinical outcomes (ie, survival, healing, and root development) of the procedure.
RESULTS: Eleven articles were included in the qualitative and quantitative syntheses. Three studies were randomized controlled trials, 6 were prospective cohort studies, and 2 were retrospective cohort studies. The pooled survival and healing rates were 97.3% and 93.0%, respectively. The pooled rates of root lengthening, root thickening, and apical closure were 77.3%, 90.6%, and 79.1%, respectively. However, if 20% radiographic changes were used as a cutoff point, there were only 16.1% root lengthening and 39.8% root thickening.
CONCLUSIONS: Within the limitations of the present study, it can be concluded that RET yielded high survival and healing rates with a good root development rate. However, clinical meaningful root development after RET was unpredictable.

Brassinosteroids (BRs) are well-characterized growth hormones that are critical for plant growth, development, and productivity. Genetic and molecular studies have revealed the key components of BR biosynthesis and signaling pathways. The membrane-localized BR signaling receptor, BRASSINOSTEROID INSENSITIVE1 (BRI1) binds directly to its ligand and initiates series of signaling events that led to the activation of BR transcriptional regulators, BRASSINAZOLE RESISTANT1 (BZR1) and BRI1-ETHYL METHANESULFONATE-SUPPRESSOR1 (BES1/BZR2) to regulate the cellular processes. Insights from Arabidopsis research revealed tissue and cell type-specific roles of BR in controlling cell elongation and maintenance of stem cell niche in roots. More recently, BRs have gained much attention in regulating the root growth during nutrient deficiency such as nitrogen, phosphorus, and boron. Differential distribution of nutrients in the rhizosphere alters BR hormone levels and signaling to reprogram spatial distribution of root system architecture (RSA) such as a change in primary root growth, lateral root numbers, length, and angle, root hair formation and elongation. These morpho-physiological changes in RSA are also known as an adaptive root trait or foraging response of the plant. In this review, we highlight the role of BRs in regulating RSA to increase root foraging response during fluctuating nutrient availability.

Endodontic treatment of immature necrotic teeth is a real challenge. Recently, a biologically based treatment strategy, referred to as regeneration, has been introduced. Tissue regeneration requires the presence of stems cells, a scaffold, and growth factors. Endodontic regeneration may improve the prognosis of immature necrotic teeth by re-establishing the functional pulpal tissue and further development of the root. However, the tissue formed in the pulpal space may not be original pulp tissue, and in some cases, it may result in uncontrolled calcification of the pulp. This study reports a case of successful endodontic regeneration and compares this process with the normal development of the contralateral tooth. Finally, it discusses the nature of the tissue formed during endodontic regeneration.