Ginsenoside Rb1 alleviates lipopolysaccharide-induced inflammation in human dental pulp cells via the PI3K/Akt, NF-κB, and MAPK signalling pathways.

AIM: Among numerous constituents of Panax ginseng, a constituent named Ginsenoside Rb1 (G-Rb1) has been studied to diminish inflammation associated with diseases. This study investigated the anti-inflammatory properties of G-Rb1 on human dental pulp cells (hDPCs) exposed to lipopolysaccharide (LPS) and aimed to determine the underlying molecular mechanisms. METHODOLOGY: The KEGG pathway analysis was performed after RNA sequencing in G-Rb1- and LPS-treated hDPCs. Reverse-transcription polymerase chain reaction (RT-PCR) and western blot analysis were used for the assessment of cell adhesion molecules and inflammatory cytokines. Statistical analysis was performed with one-way ANOVA and the Student-Newman-Keuls test. RESULTS: G-Rb1 did not exhibit any cytotoxicity within the range of concentrations tested. However, it affected the levels of TNF-α, IL-6 and IL-8, as these showed reduced levels with exposure to LPS. Additionally, less mRNA and protein expressions of vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) were shown. With the presence of G-Rb1, decreased levels of PI3K/Akt, phosphorylated IκBα and p65 were also observed. Furthermore, phosphorylated ERK and JNK by LPS were diminished within 15, 30 and 60 min of G-Rb1 exposure; however, the expression of non-phosphorylated ERK and JNK remained unchanged. CONCLUSIONS: G-Rb1 suppressed the LPS-induced increase of cell adhesion molecules and inflammatory cytokines, while also inhibiting PI3K/Akt, phosphorylation of NF-κB transcription factors, ERK and JNK of MAPK signalling in hDPCs.

Influence of postprinting cleaning methods on the cleaning efficiency and surface and mechanical properties of three-dimensionally printed resins.

STATEMENT OF PROBLEM: The outcome of photopolymerized 3-dimensional (3D) printing is influenced by the methods used for postprinting cleaning, yet information on postprinting cleaning is sparse. PURPOSE: The purpose of this in vitro study was to assess the cleaning efficiency and surface and mechanical properties of 3D printed resin according to postprinting cleaning methods. MATERIAL AND METHODS: Specimens were fabricated from a 3D model using resin materials (NextDent C&B MFH and DIOnavi-P. MAX) and were tested for postprinting cleaning methods for 5 minutes with isopropyl alcohol, isopropyl alcohol + ultrasonic, ethyl alcohol, ethyl alcohol + ultrasonic, and ultrasonic alone. Postpolymerization was followed for 5 minutes. The cleaning efficiency, microcomputed tomography (µCT), surface roughness, Vickers hardness, and flexural strength of the specimens were evaluated. The 1-way ANOVA test was performed after considering normality. A post hoc analysis with Bonferroni was also performed (α=.008 or.005). RESULTS: Ultrasonic in addition to cleaning solutions significantly improved the cleaning efficiency in NextDent C&B MFH specimens (P<.005), whereas ultrasonic did not affect the efficiency in DIOnavi-P. MAX specimens. No significant differences were found in surface roughness by postprinting cleaning methods in either NextDent C&B MFH or DIOnavi-P. MAX (P>.005). No significant changes in surface hardness were observed by postprinting cleaning methods (P>.008). In the NextDent C&B MFH, ethyl alcohol + ultrasonic significantly decreased the flexural strength (P<.005). There were no significant differences in the flexural strength in the DIOnavi-P. MAX (P>.005). CONCLUSIONS: Ethyl alcohol was comparable with isopropyl alcohol for use as a postprinting cleaning solution for both NextDent C&B MFH and DIOnavi-P. MAX. The addition of ultrasonic to cleaning solutions should be applied with caution. These findings suggest that different postprinting cleaning methods can be recommended depending on the 3D printed resin materials.

Effect of intra-alveolar delivery of Frondoside A on inflammatory response of delayed tooth replantation.

BACKGROUND/AIM: Frondoside A is a sea cucumber extract which is well known for its anti-inflammatory and immunomodulatory properties. The purpose of this study was to evaluate the effect of Frondoside A application in the alveolar socket on inflammatory responses after delayed replantation in rat teeth. MATERIALS AND METHODS: Human periodontal ligament cells were cultured and exposed to Frondoside A. Cell-counting kit-8 assay was performed to evaluate the cell viability and nitric oxide assay was performed to assess the anti-inflammatory effect of Frondoside A. Molars were extracted from 32 Sprague-Dawley rats and randomly divided into control and Frondoside A groups. After 30 min of extra-oral dry time, molars were replanted. In the Frondoside A group, Frondoside A solution was applied in the alveolar socket before replantation. The animals were sacrificed after 28 days and histologically and immunohistochemically evaluated. RESULTS: 0.5 µM Frondoside A showed higher cellular viability at 6 h and lower production of nitric oxide compared with other Frondoside A solutions (p < .05). The Frondoside A group demonstrated lower inflammatory resorption scores in both middle 1/3 and apical 1/3 of root compared to the control group (p < .05). The Frondoside A group showed lower levels of expression in both cathepsin K and CD45 compared with the control group (p < .05). CONCLUSIONS: Within the limits of this study, intra-alveolar delivery of Frondoside A alleviates inflammatory root resorption in delayed replantation of rat teeth.

Influence of limited mouth opening in children on intraoral scanning accuracy: An in vitro study.

BACKGROUND: Although intraoral scanning is highly reliable, little is known about its accuracy in young children with limited mouth-opening ability. AIM: To determine the accuracy of intraoral scans based on the degree of mouth opening. DESIGN: To simulate mouth opening in children with primary dentition, three groups (n = 5 per group) were allocated by maximum mouth opening of 30, 37 and 40 mm. After the primary dentition model was connected to a dental phantom, intraoral scanning was performed using iTero and TRIOS4. The scanned files were digitally evaluated. Root mean square values were calculated to assess trueness and precision. RESULTS: iTero showed deviations of three-dimensional trueness of 0.067 ± 0.008, 0.063 ± 0.001 and 0.065 ± 0.005 mm, and TRIOS4 of 0.07 ± 0.002, 0.064 ± 0.003 and 0.066 ± 0.002 mm in the 30, 37 and 40 mm groups, respectively. There were no significant differences in either mouth opening (p > .017) or the intraoral scanners (p > .05). The same statistical results were obtained for precision, with the exception of the 30 mm of mouth opening. CONCLUSIONS: Within the limits of this study, limited mouth opening hardly influenced the accuracy of intraoral scanning.

Evaluation of delphinidin as a storage medium for avulsed teeth.

BACKGROUND: Delphinidin (DP), an anthocyanidin found in blueberries, has antioxidant and anti-inflammatory effects. This study aimed to investigate the efficacy of DP as a storage medium for avulsed teeth. METHODS: Human periodontal ligament cells were cultured and exposed to DP solution (10, 50, and 100 µM), Dulbecco's modified Eagle's medium, Hank's balanced salt solution and tap water. Cell counting kit-8 assays were performed after 0.5, 1, 6, and 24 h to measure the cell viability. Nitric oxide assays and gelatin zymography were performed to evaluate the anti-inflammatory effects of DP. Reverse transcription-polymerase chain reaction was used to determine the expression levels of inflammatory cytokines. RESULTS: The viability of periodontal ligament cells was greatest at 100 µM DP. At 1 h, 100 µM DP decreased nitric oxide synthesis (p < .0167). Matrix metallopeptidase-9 activity was inhibited by DP in a dose-dependent manner (p < .0167). Moreover, treatment with 100 µM DP decreased the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 in periodontal ligament cells (p < .0167). CONCLUSIONS: Within the limits of this study, DP preserved the viability and suppressed the inflammatory response of periodontal ligament cells. These findings suggest that DP could be promising for preservation of avulsed teeth.

Accelerated Oral Healing by Angelica gigas Nakai from Hot Melt Extrusion Technology: An In Vitro Study.

Background and Objectives: In spite of the oral environment being healing-prone, its dynamic changes may affect wound healing. The purpose of this study was to assess the oral wound healing effect of Angelica gigas Nakai (AG) prepared by hot-melt extrusion. Materials and Methods: Human gingival fibroblast (HGF) cells were treated with AG or AG via hot-melt extrusion (AGH) for 24 h to determine the optimal concentration. For evaluating the anti-inflammatory effect of AG and AGH, a nitric oxide assay was performed under lipopolysaccharide (LPS) stimulation. The wound-healing effects of AG and AGH were evaluated using cell proliferation/migration assays and wound-healing marker expression through qRT-PCR. Results: Both AG and AGH showed no cytotoxicity on HGH cells. Regarding nitric oxide production, AGH significantly decreased LPS-induced nitric oxide production (p < 0.05). AGH showed a significantly positive result in the cell proliferation/cell migration assay compared with that in AG and the control. Regarding wound healing marker expression, AGH showed significantly greater VEGF and COL1α1 expression levels than those in the others (p < 0.05), whereas α-SMA expression was significantly different among the groups. Conclusions: Within the limits of this study, AGH accelerated oral wound healing in vitro.

Determination of the range of intervention timing for supernumerary teeth using the Korean health insurance review and assessment service database.

This study aimed to identify the frequency of complications during the diagnosis, observation, and treatment of supernumerary teeth or odontomas and evaluate the relationship between complications and the timing of surgical intervention. This study was conducted based on data from the Korea Health Insurance Review and Assessment Service between January 2008 and December 2019. A 2-year washout period was applied, and a follow-up period of at least 2 years was also included. During the observation period, the age at diagnosis of supernumerary teeth and odontomas was analyzed using major diagnostic codes, and the treatment codes were used to determine the interval between diagnosis and surgical intervention. The incidence rates of supernumerary teeth (1.21%) and odontomas (0.36%) were comparable to that reported in previous studies. The frequency of supernumerary teeth was the highest in the anterior region, followed by the premolar and molar regions. The average ages at diagnosis according to the location of the supernumerary teeth were 7.25, 13.98, and 16.11 years in the anterior, premolar, and molar regions, respectively. The age at diagnosis correlated with the maturity period of the teeth at the corresponding location. For the supernumerary tooth group, surgical intervention was more likely to occur when malocclusion (p < 0.0001) or tooth eruption disturbances (p < 0.0001) were present or dentigerous cysts were absent (p = 0.006). For the odontoma group, malocclusion (p = 0.251) was not correlated with surgical intervention. When tooth eruption disturbances (p = 0.002) and dentigerous cysts (p < 0.0001) were present, surgical intervention was more likely to occur. Pediatric dentists should conduct timely clinical checks and periodic follow-ups to prevent complications and unnecessary orthodontic treatments in patients with supernumerary teeth or odontomas.

Bisphenol A release from commercially available 3-dimensionally printed resins and human cell apoptosis to bisphenol A: an in-vitro study.

Bisphenol A (BPA) from dental materials may be linked to children's health issues. This study aimed to assess the release of BPA from commercially available 3-dimensional (3D)-printed resin materials and evaluate BPA-related apoptotic effects on human periodontal ligament cells and gingival fibroblasts. Commercially available 3D-printed resin materials for prosthodontic use were selected as follows: NextDent C&B MFH (3D Systems, Rock Hill, SC, USA), DIOnavi-P. MAX (Dio Co., Busan, Korea), and DIOnavi-Denture02 (Dio Co., Busan, Korea). Identical cuboidal samples (1 cm × 1 cm × 0.5 cm) were printed from the materials and cured. BPA release was assessed using liquid chromatography/mass spectrometry (LC/MS). In addition, human gingival fibroblasts and periodontal ligament cells were exposed to various BPA solutions based on the LC/MS results. Cell Counting kit-8 (CCK-8) and real-time polymerase chain reaction analyses were performed to evaluate BPA-related apoptotic effects. The LC/MS analysis confirmed that none of the 3D-printed resin materials released BPA after curing. Both human gingival fibroblasts and periodontal ligament cells showed lower viability after BPA exposure. Regarding apoptosis-related gene expression, Caspase10 (CASP10) expression in periodontal ligament cells was significantly different in the BPA solutions (p < 0.05). The expression of BAX and Capspase8 (CASP8) in gingival fibroblasts was significantly increased by BPA in a dose-dependent manner (p < 0.05). Within the limitations of this study, the 3D-printed resin materials were not found to release BPA. This finding implies that 3D-printed resin materials are not associated with potential BPA-related risks in children.

Three-dimensional evaluation of tooth preparation forms in paediatric zirconia crowns: An in vitro study.

BACKGROUND: Though prefabricated zirconia crowns (PZCs) differ from stainless steel crowns and have different preparation guidelines for optimal crown adaptation, little is known about how clinicians prepare teeth for PZCs. AIM: To investigate the prepared tooth forms for PZCs and identify the shared patterns of tooth preparation. DESIGN: Twenty participants prepared primary maxillary first molars and mandibular second molars for PZCs. A model with ideally prepared tooth was digitally generated as a reference. The prepared teeth were digitally scanned and superimposed on the reference. Three-dimensional analysis software was used to evaluate the discrepancy between ideal and prepared surface for overall surface and subdivided area. RESULTS: Half of the surfaces received excessive reduction, and 24% showed error within 0.2 mm (p < .001) in maxilla. 41.6% of surfaces showed error within 0.2 mm, and 20% were excessively prepared (p = .002) in mandible. The highest discrepancies were found at the mesiopalatal line angles (maxillary) and at the distobuccal line angles (mandibular). Significant discrepancies were observed on the occlusal surfaces, especially at the cusps. CONCLUSIONS: Tooth preparations for PZCs showed wide variations related to depth among the participants.

Stress distribution in pediatric zirconia crowns depending on different tooth preparation and cement type: a finite element analysis.

BACKGROUND: In clinical settings, tooth preparation for prefabricated zirconia crowns (PZCs) in the primary dentition varies widely. However, knowledge about the biomechanical behavior of PZCs in various clinical settings is limited. This study was conducted to evaluate the biomechanical behavior of PZCs in different clinical settings using 3-dimensional finite element analysis. METHODS: 3-dimensional models of the PZC, cement, and tooth with six different conditions were simulated in primary molar teeth, incorporating cement thickness (100, 500, and 1000 µm) and cement type (resin-modified glass ionomer cement and resin cement). A total of 200 N of occlusal force was applied to the models, both vertically and obliquely as representative cases. A general linear model univariate analysis with partial eta-squared (ηp2) was performed to evaluate the relative effects of the variables. RESULTS: The overall stress of tooth was increased as the cement space increases under oblique loading. The von Mises stress values of the resin cements were significantly higher than those of the resin-modified glass ionomer cements for all cement thicknesses (p < .05). The effect size of the cement type (ηp2 = .519) was more dominant than the cement thickness (ηp2 = .132) in the cement layer. CONCLUSIONS: Within the limits of this study, cement type has a greater influence on the biomechanical behavior of PZCs than cement thickness.

The perspective of undergraduate dental students on web-based learning in pediatric dentistry during the COVID-19 pandemic: a Korean multicenter cross-sectional survey.

BACKGROUND: The COVID-19 pandemic changed the world and created a shift in the dental education program. This sudden change in the dental education program may have affected the academic standards of dental students. This study aimed to evaluate the overall satisfaction and effectiveness of online learning in pediatric dentistry of undergraduate dental students' during the COVID-19 pandemic in South Korea. METHODS: An anonymous online survey was sent to three dental schools, and responses were collected from dental school students. Questions included the demographics, perspectives of online classes, comparison of online and offline pediatric dentistry classes and opinions on how dental schools are handling the pandemic. Students' perspectives on online classes were evaluated based on satisfaction with online education. Data were analyzed using the Kruskal-Wallis test and the Mann-Whitney U test. RESULTS: Most students took online classes from home (80.9%) using Zoom (50.4%). The majority reported overall program satisfaction (74.1%) and agreed that universities implemented online classes well (55%). Students who were in favor of online classes responded more positively to questions on the effectiveness and safety of online learning (p < 0.05). Regardless of satisfaction with online education, the students agreed that the online education shift was the right decision in pandemic outbreak. CONCLUSIONS: Dental students in South Korea preferred and adapted well to the web-based learning program in pediatric dentistry during COVID-19 pandemic.

Void characteristics and tortuosity of calcium silicate-based cements for regenerative endodontics: a micro-computed tomography analysis.

BACKGROUND: Internal voids of materials can serve a hub for microorganism and affect the sealing ability. This study aimed to evaluate the sealing performance of calcium silicate-based cements in immature teeth treated with regenerative endodontics. METHODS: Twenty single root canals from immature permanent premolars were prepared using regenerative endodontic protocols. The root canals were randomly divided into two groups and sealed with mineral trioxide aggregate (MTA) and Biodentine (BD). The teeth were kept in humid environment for 7 days and scanned using micro-computed tomography. The voids within the cements were segmented and visualized using image processing, incorporating the modified Otsu algorithm. The porosity of each sample was also calculated as the ratio between the number of voxels of voids and the volume of the cements. Tortuosity was also calculated using the A-star algorithm. RESULTS: Voids larger than 70 µm were predominantly observed in the top and interfacial surface of cements. The others were evenly distributed. MTA and BD showed the same level of porosity and tortuosity at interfacial surfaces. In inner surfaces, MTA showed more less porosity and tortuosity compared to BD (p < 0.05). CONCLUSIONS: There were no differences in sealing performance between MTA and BD.

Validation of a three-dimensional printed model for training of surgical extraction of supernumerary teeth.

INTRODUCTION: This study aimed to validate a three-dimensional (3D) printed model to provide training for supernumerary teeth (SNTs) extraction. MATERIALS AND METHODS: Each of the 30 participants, grouped as experienced and without experience, conducted two identically simulated surgeries on a 3D-printed replica of human mixed dentition with a SNT. The surgery time, area of bony window and volume of removed material were measured; subsequently, responses to a five-item questionnaire were recorded. The collected data were statistically analysed. RESULTS: The surgery time was 228.37 ± 141.53 seconds and 125.47 ± 53.03 seconds in the first and second surgery, respectively. The training significantly decreased the surgery time in the participants without experience (P = .000). However, there were no significant differences in the area of window opening (P = .271) and volume of removed material between the two surgeries (P = .075). The participants who perceived educational benefits accounted for more than 60% of the respondents for every question. Participants without experience in SNT extraction showed a tendency to rate a higher score than did those with experience. CONCLUSIONS: A 3D-printed model for surgical extraction of a SNT can improve surgical skill and, especially, shorten the learning curve in beginners.

Three-Dimensional Digitalized Surface and Volumetric Analysis of Posterior Prefabricated Zirconia Crowns for Children.

Objectives: This study was designed to compare the surface morphologies and volumes of posterior prefabricated zirconia crowns and posterior stainless steel crowns (SSCs) using digitalized three-dimensional (3D) reconstructed images. Study design: We tested prefabricated zirconia crowns (NuSmile ZR; Orthodontic Technologies, Houston, TX, USA) and SSCs (Kids Crown; Shinhung, Seoul, Korea) used to restore left maxillary and mandibular molars. A Rainbow scanner (Dentium, Seoul, Korea) was used to digitise the inner and outer surface morphologies of all crowns. The data were superimposed and evaluated using 3D software. The differences between the outer and inner surfaces and inner volume were measured. Results: The differences between the two types of crowns differed by tooth surface. At the occlusal surface, the differences were greater at the cusp tip than the fossa. At the axial level, the differences decreased toward the gingival margins. Also, relative volumetric ratios varied. Conclusions: Tooth preparation prior to placement of prefabricated zirconia crowns requires special consideration. Greater amounts of tooth reduction are necessary for posterior zirconia crowns than for SSCs. The occlusal surface requires more tooth reduction than the axial surface and the gingival margin.

Cytotoxicity of two fluoride-releasing adhesive tapes.

Sodium fluoride-polyvinyl alcohol (NaF-PVA) tape was developed to deliver fluoride to teeth by adding fluoride to polymer tape. Previous studies have demonstrated that tapes are effective and have antimicrobial properties. This study aimed to evaluate the cytotoxicity of two fluoride-releasing adhesive tapes. We investigated two polyvinyl alcohol (PVA) tapes: (i) a fluoride-PVA (F-PVA) tape, and (ii) a pullulan-incorporated F-PVA (PF-PVA) tape. The cytotoxicity test was conducted on human gingival fibroblasts (HGF) and human periodontal ligament (PDL) cells. Using an adhesive tape containing fluoride, we performed the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on these cells. Genetic analysis of the cells was performed to conduct a stability test on humans. In the MTT assay, PF-PVA had 66% greater cytotoxicity than control by PDL and 69% by HGF. F-PVA showed less cytotoxicity than PF-PVA by 29% in PDL and 33% in HGF. Gene ontology (GO) analysis and gene set enrichment analysis (GSEA) were performed as gene expression analyses. GO analysis indicated that PF-PVA displayed more expression changes of genes related to cytotoxicity than F-PVA. In addition, GSEA found more inflammatory response associations in PF-PVA than in F-PVA. MTT and genetic testing yielded comparable results.

Osteogenic potential of Frondoside A in human periodontal ligament cells: an RNA-Seq analysis.

PURPOSE: The aim of this study was to evaluate the effects of Frondoside A (FA) on the osteogenic differentiation of human periodontal ligament (PDL) cells. METHODS: Human PDL cells were cultured in osteogenic medium and treated with FA at concentrations of 0, 0.05, and 0.2 µM for 14 days. The expression levels of genes associated with osteogenic differentiation were assessed using quantitative real-time polymerase chain reaction analysis. Subsequently, RNA sequencing was performed to identify enriched gene sets following FA treatment. Alkaline phosphatase (ALP) activity was measured to confirm the osteogenic potential of FA. RESULTS: Treatment with 0.2 µM FA significantly increased the expression levels of runt-related transcription factor 2 (RUNX2), ALP, and osteocalcin (OCN) at day 3, while also significantly elevating the expression of dentin sialophosphoprotein (DSPP), RUNX2, ALP, OCN, and osterix (OSX) at day 14 (P<0.017). Hallmark gene sets enriched during FA treatment were associated with the KRAS (normalized enrichment score [NES]=2.02, Q=0.000), interferon alpha (IFN-α) (NES=1.88, Q=0.001), IFN-γ (NES=1.85, Q<0.001), hypoxia (NES=1.79, Q=0.001), and p53 (NES=1.77, Q=0.001) signaling pathways. Additionally, treatment with 0.2 µM FA significantly intensified ALP staining at day 14 (P<0.05). CONCLUSIONS: Within the limitations of this study, FA treatment influenced periodontal regeneration by promoting the osteogenic differentiation of human PDL cells.

Biocompatibility and Bioactivity of a Dual-Cured Resin-Based Calcium Silicate Cement: In Vitro and in vivo Evaluation.

INTRODUCTION: This study aimed to assess the biocompatibility and bioactivity of a dual-cured resin-based calcium silicate cement in vitro and in vivo. METHODS: For in vitro analyses, standardized samples were prepared using TheraCal LC, TheraCal PT, and ProRoot MTA. The amount of residual monomer released from TheraCal LC and TheraCal PT was assessed using liquid chromatography/mass spectrometry. Calcium ion release from the materials was evaluated using inductively coupled plasma-optical emission spectroscopy. Scanning electron microscopy and energy-dispersive X-ray spectroscopy were used to determine the calcium weight volume in the materials. For in vivo analysis, a rat direct pulp capping model with TheraCal LC, TheraCal PT, and ProRoot MTA groups (n = 16 per group) was used. The rats were euthanized after 7 or 28 days, and histological and immunohistochemical analyses (CD68 and DSPP) were performed. RESULTS: Bisphenol A-glycidyl methacrylate and polyethylene glycol dimethacrylate release from TheraCal PT was lower than that from TheraCal LC (P < .05). Similar results were obtained for calcium-ion release and calcium weight volume, with ProRoot MTA showing the highest values. In the in vivo evaluation, TheraCal PT showed significantly greater hard tissue formation than TheraCal LC (P < .017). TheraCal PT showed lower CD68 expression and greater DSPP expression than TheraCal LC (P < .017). There were no significant differences in the expression of CD68 or DSPP between the TheraCal PT and ProRoot MTA groups. CONCLUSIONS: Within the limitations of this study, the biocompatibility and bioactivity of TheraCal PT could be comparable to those of ProRoot MTA.

Three-dimensional analysis of the alveolar ridge profiles of maxillary central incisors in children for autotransplantation.

BACKGROUND: Sufficient alveolar housing is fundamental to ensure the favorable prognosis of autotransplanted teeth. However, little is known about the alveolar ridge profiles of the anterior maxilla in children. Therefore, this study aimed to investigate the alveolar ridge profiles of the anterior maxilla in growing children. METHODS: A total of 169 Korean children aged 10-13 years old were included in this retrospective study. Demographic data and cone-beam computed tomography scans of 244 maxillary central incisors were collected. For each tooth, the alveolar ridge thickness was determined at 1-, 3-, and 5-mm levels below the cemento-enamel junction. The alveolar process height and labial concavity were also evaluated. Statistical analyses were performed to evaluate differences according to age and sex. RESULTS: The alveolar ridge thickness did not differ according to age. The alveolar ridge thickness in males was significantly greater than that in females among those aged 10 and 11 years. The average alveolar process height was 17.43 ± 2.22 mm. The alveolar process height hardly changed with age from 10-13 years, whereas the alveolar process height of males was significantly greater compared with that of females among those aged 10 years. The labial concavity was approximately 150˚, with no significant differences between age and sex. CONCLUSIONS: Within the limits of this study, the anatomy of the alveolar ridge in the maxillary central incisors showed sufficient capacity as a recipient site for autotransplantation using mandibular premolars, especially in males. These findings serve as a valuable resource for facilitating autotransplantation in children.

Effects of Doxycycline-Loaded NO-Releasing Nanomatrix Gel on Delayed Replanted of Rat Molar.

BACKGROUND/AIM: Tooth avulsion and delayed replantation may cause inflammatory responses and root resorption of the tooth. The aim of this study is to investigate the effect of a doxycycline-loaded nitric oxide-releasing nanomatrix (DN) gel on the delayed replantation of avulsed rat teeth, with a focus on assessing the gel's potential to promote regeneration and inhibit complications associated with the replantation process. MATERIALS AND METHODS: Twenty-four right maxillary first molars from male Sprague-Dawley rats were atraumatically extracted using sterile extraction forceps. The molars were dried for 1 h at room temperature (approximately 23 °C) and divided into four groups according to the root conditioning methods after extra-alveolar 60-min drying: Group 1, no root conditioning treatment prior to replantation; Group 2, soaking in 2% NaF solution for 5 min before replantation; Group 3, 5-min soaking in NO gel and injection of the gel into the alveolar socket; Group 4, 5-min soaking in DN gel and injection of the gel into the alveolar socket before replantation. The animals were euthanized four weeks after the operation and the specimens were evaluated histologically. RESULTS: The use of NO gel alone showed better anti-inflammatory and periodontal effects than the control group, but it did not show a significant effect compared to the group using NaF. When using NO gel loaded with doxycycline, it showed a significant anti-inflammatory effect compared to the control group and showed a similar inhibitory effect to the group using NaF. CONCLUSIONS: Within the limits of this study, in delayed replantation situations, the control of inflammatory resorption and replacement resorption is an important factor for achieving a better prognosis of replanted teeth. Root surface treatment with DN gel decreased root resorption after delayed replantation.

Differential gene expression profiles of periodontal soft tissue from rat teeth after immediate and delayed replantation: a pilot study.

PURPOSE: In dental avulsion, delayed replantation usually has an uncertain prognosis. After tooth replantation, complex inflammatory responses promote a return to periodontal tissue homeostasis. Various types of cytokines are produced in the inflammatory microenvironment, and these cytokines determine the periodontal tissue response. This study aimed to identify the gene expression profiles of replanted teeth and evaluate the functional differences between immediate and delayed replantation. METHODS: Maxillary molars from Sprague-Dawley rats were extracted, exposed to a dry environment, and then replanted. The animals were divided into 2 groups according to the extra-oral time: immediate replantation (dry for 5 minutes) and delayed replantation (dry for 60 minutes). Either 3 or 7 days after replantation, the animals were sacrificed. Periodontal soft tissues were harvested for mRNA sequencing. Hallmark gene set enrichment analysis was performed to predict the function of gene-gene interactions. The normalized enrichment score (NES) was calculated to determine functional differences. RESULTS: The hallmark gene sets enriched in delayed replantation at 3 days were oxidative phosphorylation (NES=2.82, Q<0.001) and tumor necrosis factor-alpha (TNF-α) signaling via the nuclear factor kappa light chain enhancer of activated B cells (NF-κB) pathway (NES=1.52, Q=0.034). At 7 days after delayed replantation, TNF-α signaling via the NF-κB pathway (NES=-1.82, Q=0.002), angiogenesis (NES=-1.66, Q=0.01), and the transforming growth factor-beta signaling pathway (NES=-1.46, Q=0.051) were negatively highlighted. CONCLUSIONS: Differentially expressed gene profiles were significantly different between immediate and delayed replantation. TNF-α signaling via the NF-κB pathway was marked during the healing process. However, the enrichment score of this pathway changed in a time-dependent manner between immediate and delayed replantation.