Root Resorption Of Deciduous Teeth Research Articles

Root resorption of primary molars and dental development of premolars in children with Osteogenesis Imperfecta medicated with bisphosphonates, grouped according to age and gender

BackgroundOsteogenesis imperfecta (OI) is an inherited disorder characterized by bone fragility and skeletal alterations. The administration of bisphosphonates (BPs) to patients with OI reduces pain, thereby improving their quality of life. The main mechanism of action of BPs is the inhibition of osteoclast action. In the oral cavity of children with OI during growth and development, physiological processes that require the function of osteoclasts occur. The aim of this investigation was to study the dental development of premolars and the root resorption of primary molars in children with OI medicated with BPs according to age and sex.MethodsAn observational and analytical study was designed. The study sample consisted of 26 6- to 12-year-old children with a confirmed diagnosis of OI treated with BPs with available panoramic radiographs. The control group consisted of 395 children with available panoramic radiographs. Both groups were divided into subgroups according to sex and age. The third quadrant was studied, focusing on the first left temporary molar (7.4), the second left temporary molar (7.5), the first left permanent premolar (3.4) and the second left permanent premolar (3.5). The Demirjian method was used to study the dental development of 3.4 and 3.5, and the Haavikko method was used to study the root resorption of 7.4 and 7.5. The Mann‒Whitney U test was used for comparisons, and p < 0.05 indicated statistical significance.ResultsThe mean chronological age of the 421 patients was 9.21 years (95% CI 9.05–9.37). The sample was reasonably balanced by sex, with 52.5% (221 patients) boys versus 47.5% (200 patients) girls. Delayed exfoliation and tooth development were described in children with OI (p = 0.05). According to sex, the root resorption of primary molars and tooth development were significantly lower in boys in both groups and in girls in the OI group, but the differences between the age groups were not significant.ConclusionsChildren with OI treated with BPs exhibit delayed dental development of the premolars and delayed root resorption of the primary molars. Boys exhibited delays in both variables, but the differences by age subgroup were not significant. These clinical findings support the importance of clinically and radiographically monitoring the dental development and root resorption of primary teeth in children with OI treated with BPs to avoid alterations of the eruptive process.

Effect of α7 nAChR-autophagy axis of deciduous tooth pulp stem cells in regulating IL-1β in the process of physiological root resorption of deciduous teeth.

Physiological root resorption of deciduous teeth is a normal phenomenon occurring during the developmental stages of children. Previous research has indicated the pivotal role of the inflammatory microenvironment in this process, although the specific mechanisms remain unclear. This study is aimed at elucidating the involvement of the alpha7 nicotinic acetylcholine receptors (α7 nAChR)-autophagy axis in the regulation of the inflammatory microenvironment during physiological root resorption in deciduous teeth. Samples were collected from deciduous teeth at various stages of physiological root resorption, and deciduous dental pulp stem cells (DDPSCs) were isolated and cultured during the mid-phase of root resorption. The findings revealed a substantial infiltration of the pulp of deciduous teeth at the mid-phase of root resorption, characterized by elevated expression levels of α7 nAChR and IL-1β. Significantly increased IL-1β and α7 nAChR expressions were observed in DDPSCs during the mid-phase of root resorption, with α7 nAChR demonstrating a regulatory effect on IL-1β. Moreover, evidence suggested that mechanical stress may act as a trigger, regulating autophagy and IL-1 expression via α7 nAChR. In conclusion, mechanical stress was identified as a regulator of autophagy in DDPSCs through α7 nAChR, influencing the expression of IL-1β and contributing to the formation of the inflammatory microenvironment. This mechanism plays a crucial role in the physiological root resorption of deciduous teeth. KEY MESSAGES: The pulp of deciduous teeth at mid-phase of root resorption was heavily infiltrated with high expression of α7nAChR and IL-1β. α7 nAChR acts as an initiating factor to regulate IL-1β through autophagy in DDPSCs. Mechanical stress can regulate autophagy of DDPSCs through α7 nAChR and thus affect IL-1β expression and inflammatory microenvironment formation in physiological root resorption in deciduous teeth.

Circadian clock genes REV-ERBα regulates the secretion of IL-1β in deciduous tooth pulp stem cells by regulating autophagy in the process of physiological root resorption of deciduous teeth

Physiological root resorption is a common occurrence during the development of deciduous teeth in children. Previous research has shown that the regulation of the inflammatory microenvironment through autophagy in DDPSCs is a significant factor in this process. However, it remains unclear why there are variations in the autophagic status of DDPSCs at different stages of physiological root resorption. To address this gap in knowledge, this study examines the relationship between the circadian clock of DDPSCs, the autophagic status, and the periodicity of masticatory behavior. Samples were collected from deciduous teeth at various stages of physiological root resorption, and DDPSCs were isolated and cultured for analysis. The results indicate that the circadian rhythm of important autophagy genes, such as Beclin-1 and LC3, and the clock gene REV-ERBα in DDPSCs, disappears under mechanical stress. Additionally, the study found that REV-ERBα can regulate Beclin-1 and LC3. Evidence suggests that mechanical stress is a trigger for the regulation of autophagy via REV-ERBα. Overall, this study highlights the importance of mechanical stress in regulating autophagy of DDPSCs via REV-ERBα, which affects the formation of the inflammatory microenvironment and plays a critical role in physiological root resorption in deciduous teeth.

Apoptosis in physiological root resorption of primary teeth.

During physiological root resorption of deciduous teeth, apoptotic cell death triggered by physiological processes might play a role in physiological root resorption in addition to collagen destruction. Little information has been obtained about the sequence of events and the mechanism responsible for the physiological death of pulp tissue cells. This study evaluated apoptotic cell death in the pulp tissue of deciduous teeth that showed various levels of physiological root resorption. The role of apoptosis in pulp tissue elimination during the physiological resorption of deciduous teeth was also examined. For orthodontic reasons, 12 healthy permanent teeth and the pulp of 34 healthy deciduous teeth showing signs of early and advanced root resorption were extracted. To detect apoptotic cells in the pulp tissue, the terminal deoxynucleotidyl transferase dUTP nick end-labeling (TUNEL) method and transmission electron microscopy (TEM) were used. The apoptotic index (AI) values of the study groups were determined using the TUNEL method. This technique required calculating the Apoptag positive(+) fibroblast cell ratio in accordance with the total number of cells. No statistically significant differences were found for the AI values of each study group (p>0.05). Apoptosis was detected in the vascular endothelial cells, the mononuclear inflammatory cells, and the odontoblasts of the connective pulp tissue. In the pulp tissue, evaluated using TEM, various pulp cells were observed at distinct stages of apoptosis. The similarity between the AI values for both study groups suggested that in early and advanced stages of resorption, apoptosis may contribute to the regulation of the pulp cell population in a way that does not relate to the physiological process of deciduous teeth root resorption.

Quantitative Assessment of Dentine Sialophosphoprotein, Aspartate Aminotransferase and Lactate Dehydrogenase in Gingival Crevicular Fluid of Teeth with Root Resorption

Root resorption is a shortening of root dentine which occurs physiologically in deciduous teeth. The present study aimed to quantify dentine sialophosphoprotein (DSPP), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in gingival crevicular fluid (GCF) during the physiological process of root resorption of deciduous teeth. A cross-sectional study was conducted with 25 children aged between 4 and 10 years old. GCF was collected from the gingival sulcus using periopaper strips from the upper first deciduous molar (n = 45). The samples were divided equally into three groups, no resorption (R0), moderate resorption (RM) and severe resorption (RS), based on the existing radiographs taken. The GCF samples were then analysed using an enzyme-linked immunosorbent assay (ELISA) kit to determine the DSPP concentration levels and BioAssays System kit for AST and LDH. One-way ANOVA was used to determine the statistical differences between the means of the DSPP, AST and LDH concentration level in the three groups. A difference was considered significant when p &lt; 0.05. High concentration levels of DSPP were significantly noted in RS (p &lt; 0.05), compared to RM and R0. AST also portrayed significant high activity level (p &lt; 0.05) similar to DSPP but LDH showed no significant changes between groups (p &gt; 0.05). The high quantification of DSPP and AST levels in the severe and moderately resorbed roots indicated the potential use of this protein as a biomarker for detecting moderate-severe stages of root resorption.

Exosomes Derived From Hypoxia-Conditioned Stem Cells of Human Deciduous Exfoliated Teeth Enhance Angiogenesis via the Transfer of let-7f-5p and miR-210-3p

Physiological root resorption of deciduous teeth is a normal phenomenon. How the angiogenesis process is regulated to provide adequate levels of oxygen and nutrients in hypoxic conditions when the dental pulp tissue is reduced at the stage of root resorption is not fully understood. In this study, we designed hypoxic preconditioning (2%) to mimic the physiological conditions. We isolated exosomes from hypoxic-preconditioned SHED (Hypo-exos) cells and from normally cultured SHED cells (Norm-exos). We found that treatment with Hypo-exos significantly enhanced the growth, migration and tube formation of endothelial cells in vitro compared with Norm-exos. We also performed matrigel plug assays in vivo and higher expression of VEGF and higher number of lumenal structures that stained positive for CD31 were found in the Hypo-exos treated group. To understand the potential molecular mechanism responsible for the positive effects of Hypo-exos, we performed exosomal miRNA sequencing and validated that Hypo-exos transferred both let-7f-5p and miR-210-3p to promote the tube formation of endothelial cells. Further study revealed that those two miRNAs regulate angiogenesis via the let-7f-5p/AGO1/VEGF and/or miR-210-3p/ephrinA3 signal pathways. Finally, we found that the increased release of exosomes regulated by hypoxia treatment may be related to Rab27a. Taking these data together, the present study demonstrates that exosomes derived from hypoxic-preconditioned SHED cells promote angiogenesis by transferring let-7f-5p and miR-210-3p, which suggests that they can potentially be developed as a novel therapeutic approach for pro-angiogenic therapy in tissue regeneration engineering.

Advances in the Study of the Mechanisms of Physiological Root Resorption in Deciduous Teeth.

Physiological root resorption of deciduous teeth is a complex physiological process that is essential for the normal replacement of deciduous teeth and permanent teeth in clinical practice, but its importance is often overlooked due to the presence of permanent teeth. This physiological process includes not only the resorption of hard tissues of deciduous teeth, such as dentin and cementum, but also the elimination of soft tissues, such as pulp and periodontal ligament (PDL). However, the mechanisms of physiological root resorption are not yet clear. In this article, the advances of research on the mechanisms related to physiological root resorption will be reviewed in two main aspects: hard tissues and soft tissues of deciduous teeth, specifically in relation to the effects of inflammatory microenvironment and mechanical stress on the resorption of hard tissues, the repair of hard tissues, and the elimination and the histological events of soft tissues.

Immunohistochemistry of resorption and inflammation factors in the periodontal ligament of human deciduous teeth.

The understanding of the biological mechanisms involved in root resorption in deciduous teeth is important to the future development of preventive measures and treatments of this condition. The aim of the present study was to compare the expression and immunostaining of iNOS, MMP-9, OPG and RANKL in the periodontal ligament (PDL) of deciduous teeth with physiologic root resorption (GI), inflammatory pathological root resorption (GII) and permanent teeth (GIII), the negative control. Teeth in GI (n = 10), GII (n = 10) and (GIII) (n = 10) were submitted to immunohistochemical analysis to determine the expression of iNOS, MMP-9, OPG, and RANKL. The immunostaining was analysed by optical density. Statistical analysis included one-way ANOVA, followed by Student-Newman-Keuls post hoc test (p < 0.05). The results showed that iNOS, MMP-9 and RANKL expression in the PDL was higher in GII compared to GI and GIII (p < 0.05). Moreover, RANKL expression was higher in GI compared to GIII (p < 0.001), while OPG immunolabelling was lower in GII compared to GI and GIII (p < 0.001). The PDL of deciduous teeth bearing inflammatory processed exhibited upregulation of resorption-associated factors as well as enzymes related to tissue degradation which, in turn explains the exacerbation and greater susceptibility of those teeth to root resorption process.

Management of internal root resorption in primary mandibular right first molar: A case report with four-year follow-up

Internal inflammatory root resorption in primary teeth is a well-known entity with unknown prevalence. The diagnosis and conservative treatment of such a lesion has perplexed practitioners for decades. The management of a non-perforating internal root resorption is long been debated by general dentists and paediatric dentists alike. This case presentation describes the case of a 4-year old boy with non-perforating internal root resorption in a primary molar treated successfully with endodontic procedure and monitored routinely for four years. The objective here was to suggest a minimally-invasive treatment alternative to conventional treatment practices.

A minimally invasive technique for primary tooth extraction: a case report

ABSTRACT Root resorption is characterized by the loss of cementum and / or dentin from the tooth root as a result of internal or external odontoclastic action. This case reports a premature cervical root resorption of deciduous teeth in an 8-year-old boy. Large root resorption on the mesial faces of the maxillary and mandibular right and left deciduous canines (teeth #53, #63, #73 and #83), with asymptomatic pulp involvement, was detected during routine radiographic examination for orthodontic planning. The patient was managed with extraction of the affected teeth using two different techniques: conventional and alternative. The conventional technique, forceps, was used for the maxillary and mandibular left canines (teeth #63 and #73). And alternative technique using the periotome device, usually required for extraction during dental implant surgery, was used for the maxillary and mandibular right canines (teeth #53 and #83). The periotome device showed to be an alternative to improve pediatric surgery due to better patient behavior and healing, and to reduced procedure length.

Pathological root resorption as a possible intrusive injury of a deciduous mandibular second molar – A unique clinical vignette

A primary teeth and its permanent tooth germ are most of the time seen as an inter-dependent units, where each one of them interacts with and depends on each other. Intrusive injury is a most common type of an injury to primary dentition and requires a pediatric dentist to carefully examine not only the damaged tooth, but possible sequelae to the permanent tooth germ. Alteration in eruption and / or in development, as a consequence of inflammation / infection of the preceding primary teeth, such as: hypoplasia, morphological alteration on the dental crown or total arrest of radicular formation. The response of the dento-alveolar apparatus to infection is characterized by inflammation which may result in tooth resorption. This may be a consequence of infective endodontic pathosis alone or superimposed on trauma induced resorption. These infection induced resoprtions, which are generally termed inflammatory root resorptions, may occur as internal resorptions, external resorptions or combined internal - external lesions. This manuscript will present a rare case of a primary tooth onto its permanent tooth bud that showed one such case scenario of a pathological root resorption of primary teeth following a posssible intrusive injury. The condition analysed in this study belong to a patient who visited our Children's Dentistry Clinic. These conditions are often overlooked by parents mainly because less attention is given to the primary dentition and to the child’s inability to cope with the situation. The earlier this kind of condition is diagnosed, the less would be the destructive effects and the consequences on the permanent germ unit. Keywords: Anatomic proximity, Intrusive injury, Inflammatory root resorption, Pathological root resorption, Space regainer.

Pattern of Physiologic Root Resorption in Deciduous Teeth at Different Stages

Pattern of Physiologic Root Resorption in Deciduous Teeth at Different Stages

Mechanical Stress Modulates the RANKL/OPG System of Periodontal Ligament Stem Cells via α7 nAChR in Human Deciduous Teeth: An In Vitro Study.

The aim of this study was to investigate the mechanism by which periodontal ligament stem cells (PDLSCs) modulate root resorption of human deciduous teeth under mechanical stress. In this investigation, the PDLSCs were derived from deciduous and permanent teeth at different stages of root resorption. A cyclic hydraulic pressure was applied on the PDLSCs to mimic chewing forces in the oral environment. The cultured cells were characterized using osteogenic and adipogenic differentiation assays, quantitative real-time polymerase chain reaction (qRT-PCR), and Western blotting analysis. The PDLSCs exhibited the ability to induce osteoclast differentiation under certain mechanical stresses. As the expressions of RUNX2, alkaline phosphatase (ALP), and osteoprotegerin (OPG) were significantly reduced, the receptor activator of the nuclear factor kappa-B ligand (RANKL) was upregulated increasing the RANKL/OPG ratio. Under hydrodynamic pressure at 0-135 kPa, the expressions of alpha 7 nicotinic acetylcholine receptors (α7 nAChR), p-GSK-3β, and active-β-catenin were markedly upregulated in PDLSCs from unresorbed deciduous teeth. Treatment with the α7 nAChR inhibitor alpha-bungarotoxin (α-BTX) and the Wnt pathway inhibitor DKK1 may reverse the mechanical stress inducing upregulation of RANKL and reduction of RUNX2, ALP, and OPG. Alizarin red staining confirmed these results. The mechanical stress applied on the deciduous tooth PDLSCs can induce osteoclastic effects through upregulation of α7 nAChR and activation of the canonical Wnt pathway. It can be suggested that chewing forces may play a major role at the beginning of the physiological root resorption of deciduous teeth.

Effect of tumor necrosis factor α on ability of SHED to promote osteoclastogenesis during physiological root resorption

Physiological root resorption of deciduous teeth is a normal phenomenon, however, the potential mechanisms underlying this process remain unclear. This study aimed to investigate ability of stem cells from human exfoliated deciduous teeth (SHED) on promoting the osteoclastic differentiation of osteoclast precursors and clarify mechanisms underlying this process in vitro. SHED and dental pulp stem cells (DPSCs) were obtained from deciduous teeth and healthy permanent teeth. An indirect co-culture system of SHED or DPSCs were used. The osteoclast precursor peripheral blood mononuclear cells (PBMCs) were established. Ability of SHED and DPSCs in promoting osteoclastogenesis was determined using triiodothyronine receptor auxiliary protein (TRAP) staining, real-time real-time PCR (RT-PCR) and western blotting. The effect of inflammation on the pro-osteoclastogenesis ability of SHED was determined using enzyme linked immunosorbent assay (ELISA), RT-PCR and western blotting. The function of the nuclear factor-κB (NF-κB) pathway in promoting the osteoclastogenesis ability of SHED was determined using RT-PCR and western blotting. SHED exhibited an increased ability to promote osteoclastic differentiation. Expression of tumor necrosis factor-α (TNF-α) was significantly higher in SHED than in DPSCs. Expression of cathepsin K (CTSK), TRAP, and receptor-activator of nuclear-factor-κ B ligand (RANKL), RANKL/osteoprotegerin (OPG) ratio, and expression of cytoplasmic phosphorylated inhibitor of NF-κB α (p-IκBα) and nuclear p65 were markedly up-regulated in SHED post the TNF-α treatment but decreased following NF-κB inhibition. In conclusion, inflammatory cytokine TNF-α appeared to activate NF-κB pathway to up-regulate expression of NF-κB, enhancing ability of SHED in promoting osteoclastogenesis via regulating RANKL/OPG expression.

Effect of root resorption of primary teeth on the development of its permanent successors: An evaluation of panoramic radiographs in 7–8 year-old boys

Root resorption in primary teeth can occur as a physiologic or pathologic phenomenon. Physiological root resorption occurs in healthy primary teeth or primary teeth with caries but no pulp involvement, whereas pathological root resorption occurs in primary teeth with pulpal caries. Knowledge about the effects of both physiological and pathological root resorptions in primary teeth on the development of its permanent successors is important for the development of an appropriate proper treatment plan. This study aimed to evaluate the effect of root resorption of primary teeth on the development of its permanent successors in boys aged 7–8 years. This descriptive cross-sectional study comprised 71 primary mandibular molars and premolars, which were screened using 32 sheets panoramic radiographs obtained from 7–8-year-old boys. Root resorption of primary teeth appeared to have no significant effects on the development of its permanent successors in the current study.

Estimation of the effect of physiological and pathological root resorption of primary teeth on the growth of permanent teeth in 6- to 8-year-old girls using panoramic radiographs

Primary teeth (healthy or slightly carious without pulp involvement) undergo physiological root resorption, whereas pathological root resorption occurs in primary teeth with severe caries and pulp involvement. Awareness of the dentist regarding the effect of root resorption in primary teeth on the stages of growth in permanent teeth will be useful during the treatment planning process. The aim of this study was to determine the effect of physiological and pathological primary root resorption on the stages of growth in permanent teeth among girls aged 6–8 years. A total of 30 panoramic radiographs of 72 mandibular primary molars were used in this descriptive cross-sectional study. A significant difference (p < 0.05) in the growth of permanent teeth was noted between primary teeth with physiological root resorption and those with pathological root resorption. The types of root resorption in primary teeth appear to affect the growth of their successors in the permanent dentition in girls aged 6–8 years.

The Alpha 7 Nicotinic Acetylcholine Receptor of Deciduous Dental Pulp Stem Cells Regulates Osteoclastogenesis During Physiological Root Resorption.

The physiological root resorption of deciduous teeth is a normal phenomenon, but the mechanisms underlying this process are still unclear. In this study, deciduous dental pulp stem cells (DDPSCs) and permanent dental pulp stem cells (DPSCs) were derived from deciduous teeth and normal permanent teeth at different stages of resorption. In the middle stage of root resorption, DDPSCs exhibited an increase in the ability to induce osteoclast differentiation. Activation of the alpha 7 nicotinic acetylcholine receptor (α7 nAChR) by secretory mammalian Ly-6 urokinase-type plasminogen activator receptor-associated protein 1 (SLURP-1) caused a significant increase in the expression levels of NF-κB, receptor activator of nuclear factor-kappa B ligand (RANKL), and the ratio of RANKL/osteoprotegerin (OPG). These effects were inhibited by alpha-bungarotoxin (α-BTX). Furthermore, the expression levels of RANKL/OPG were significantly reduced following inhibition of NF-κB. High-strength, dynamic positive pressure increased the expression of SLURP-1 and α7 nAChR in DDPSCs in the stable stage. These data indicated that mechanical stress stimulated the expression of SLURP-1 and α7 nAChR in DDPSCs. Additionally, SLURP-1 activated α7 nAChR, thereby upregulating the expression of NF-κB and enhancing its activity, thus regulating RANKL/OPG expression and affecting the ability of DDPSCs to influence osteoclastogenesis, which likely enhances root resorption and leads to the physiological loss of deciduous teeth.

TGF-β and Physiological Root Resorption of Deciduous Teeth.

The present study was performed to examine how transforming growth factor β (TGF-β) in root-surrounding tissues on deciduous teeth regulates the differentiation induction into odontoclasts during physiological root resorption. We prepared root-surrounding tissues with (R) or without (N) physiological root resorption scraped off at three regions (R1–R3 or N1–N3) from the cervical area to the apical area of the tooth and measured both TGF-β and the tartrate-resistant acid phosphatase (TRAP) activities. The TGF-β activity level was increased in N1–N3, whereas the TRAP activity was increased in R2 and R3. In vitro experiments for the receptor activator of nuclear factor-κB (NF-κB) ligand (RANKL)-mediated osteoclast differentiation revealed that proteins from N1–N3 and R1–R3 enhanced the TRAP activity in RAW264 cells. A genetic study indicated that the mRNA levels of TGF-β1 in N1 and N2 were significantly increased, and corresponded with levels of osteoprotegerin (OPG). In contrast, the expression level of RANKL was increased in R2 and R3. Our findings suggest that TGF-β is closely related to the regulation of OPG induction and RANKL-mediated odontoclast differentiation depending on the timing of RANKL and OPG mRNA expression in the root-surrounding tissues of deciduous teeth during physiological root resorption.

Orthodontic movement in deciduous teeth.

Deciduous teeth exfoliate as a result of apoptosis induced by cementoblasts, a process that reveals the mineralized portion of the root while attracting clasts. Root resorption in deciduous teeth is slow due to lack of mediators necessary to speed it up; however, it accelerates and spreads in one single direction whenever a permanent tooth pericoronal follicle, rich in epithelial growth factor (EGF), or other bone resorption mediators come near. The latter are responsible for bone resorption during eruption, and deciduous teeth root resorption and exfoliation. Should deciduous teeth be subjected to orthodontic movement or anchorage, mediators local levels will increase. Thus, one should be fully aware that root resorption in deciduous teeth will speed up and exfoliation will early occur. Treatment planning involving deciduous teeth orthodontic movement and/or anchorage should consider: Are clinical benefits relevant enough as to be worth the risk of undergoing early inconvenient root resorption?

Pulpectomy in hyperemic pulp and accelerated root resorption in primary teeth: A review with associated case report

Persistent hemorrhage after complete amputation of coronal pulp is a common clinical finding during pulpotomy procedure in primary teeth. These teeth are best managed with pulpectomy, but they have hyperemic pulp with some remaining vital tissue. Good chemico-biomechanical preparation of primary canals cannot guarantee complete removal of this vital tissue from inaccessible areas. Use of Ca(OH) ₂ containing root filling pastes in vital pulp tissue can cause accelerated resorption of primary roots. The possible mechanism behind such extensive root resorption is discussed with review of literature. A case report of a child with 30 months follow-up is presented and discussed.