• The korean journal of orthodontics
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• v.49 no.5
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• pp.299-309
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• 2019

Objective: This study aimed to investigate the effect of pre-applied orthodontic force on the regeneration of periodontal ligament (PDL) tissues and the underlying mechanisms in tooth replantation. Methods: Orthodontic force (50 cN) was applied to the left maxillary first molars of 7-week-old male Sprague-Dawley rats (n = 32); the right maxillary first molars were left untreated to serve as the control group. After 7 days, the first molars on both sides were fully luxated and were immediately replanted in their original sockets. To verify the effects of the pre-applied orthodontic force, we assessed gene expression by using microarray analysis and real-time reverse transcription polymerase chain reaction (RT-PCR), cell proliferation by using proliferating cell nuclear antigen (PCNA) immunofluorescence staining, and morphological changes by using histological analysis. Results: Application of orthodontic force for 7 days led to the proliferation of PDL tissues, as verified on microarray analysis and PCNA staining. Histological analysis after replantation revealed less root resorption, a better arrangement of PDL fibers, and earlier regeneration of periodontal tissues in the experimental group than in the control group. For the key genes involved in periodontal tissue remodeling, including CXCL2, CCL4, CCL7, MMP3, PCNA, OPG, and RUNX2, quantitative RT-PCR confirmed that messenger RNA levels were higher at 1 or 2 weeks in the experimental group. Conclusions: These results suggest that the application of orthodontic force prior to tooth replantation enhanced the proliferation and activities of PDL cells and may lead to higher success rates with fewer complications.

• The korean journal of orthodontics
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• v.49 no.4
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• pp.205-213
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• 2019

Objective: The aim of this study was to evaluate the amount of tooth movement and histologic changes with different corticotomy designs and micro-osteoperforation in rabbits. Methods: The sample consisted of 24 rabbits divided into three experimental groups (triangular corticotomy [TC] and indentation corticotomy [IC] with flap, and flapless micro-osteoperforations [MP]) and a control. A traction force of 100 cN was applied by connecting the first premolars to the incisors. The amount of tooth movement was measured. Kruskal-Wallis test was used to assess differences in tooth movement between the groups. Micro-computed tomography, hematoxylin and eosin staining, and tartrate-resistant acidic phosphatase (TRAP) analysis were performed. Analysis of variance was applied to assess differences in TRAP-positive osteoclast count between the groups. Results: The amount of tooth movement increased by 46.5% and 32.0% in the IC and MP groups, respectively, while the bone fraction analysis showed 69.7% and 8.5% less mineralization compared to the control. There were no significant intergroup differences in the number of TRAP-positive osteoclasts. Conclusions: The micro-osteoperforation group showed no significant differences in the amount of tooth movement compared to the corticotomy groups, nor in the TRAP-positive osteoclast count compared to both corticotomy groups and control.

• Journal of dental hygiene science
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• v.21 no.3
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• pp.178-184
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• 2021

Background: As the importance of the esthetic function of teeth increases, the use of esthetic restoration materials and whitening treatment are increasing. The purpose of this study was to investigate the color change of esthetic restoration materials upon using staining and whitening toothpaste. Methods: Light curing (LC) packable composite resin, LC flowable resin, LC glass ionomer (GI), and self-curing GI specimens were colored in coffee or curry for three hours a day for seven days. After that, regular toothpaste, whitening toothpaste containing hydrogen peroxide, and whitening toothpaste containing activated charcoal were applied for three minutes three times a day for two weeks. Luminosity (L), chromaticity a (a), and chromaticity b (b) were measured using a spectrophotometer once a week. Results: In the coffee-colored group, the change in L^2*a^2*b² (E²) with time was significant (p=0.004), there was no difference for different toothpaste types (p=0.646), and there was significant difference (p<0.001) for different esthetic restorative materials. The change of E² in the curry-colored group was significant only for different esthetic restorative materials (p<0.001). In the coffee-colored group, the L, a, and b values of the light-curing GI showed greater change than other materials after staining and one week after whitening, turning dark, red, and yellow. In the curry-colored group, L did not differ for different materials and times, and a and b showed the greatest difference in light-curing GI after staining and one and two weeks after whitening. Conclusion: The use of whitening toothpaste for two weeks was not different from the use of general toothpaste in the removal of staining or whitening. Since light-curing GI is the most vulnerable to coloration, it is recommended that coloring by food chromogen should be explained in advance, before using light-curing GI for teeth restoration.

• Journal of Periodontal and Implant Science
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• v.42 no.5
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• pp.158-165
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• 2012

Purpose: Recent interest has focused on intentional replantation to restore an original tooth. Some studies have shown successful results with intentional replantation for periodontally involved teeth. For long-term success of replantation, a healthy periodontal status of the recipient site is required so that delayed replantation is more suitable for periodontally involved teeth. To reveal the ideal timing for delayed replantation of periodontally involved teeth, the healing process of extraction sockets after extraction of periodontitis-induced teeth in rats was evaluated. Methods: Twenty-eight rats were randomly divided into two groups: a control group (n=8) and test group (n=20). In the test group, periodontitis was induced by a ligature around the cervix of the mandibular first molar of all of the rats. Two weeks later, the mandibular first molars were extracted in all of the animals. The animals were sacrificed on days 0, 3, 7, and 10 after extraction and histological and immunohistochemical analysis was performed. Results: In histological analysis of the test group, inflammatory cell infiltrate was found abundantly in the remaining periodontium 3 days after tooth extraction and decreased gradually at later time points. In immunohistochemical analysis of the test group, both interleukin-6 (IL-6) and, tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) were numerous in the furcation area at each postextraction day. IL-6 was stained more heavily between 3 and 7 days after extraction; at day 10 after extraction, little staining was observed. TNF-${\alpha}$ staining was more intense at 3 days after extraction and gradually weakened at later points in time. Conclusions: Within the limits of this study, it takes at least 10 days to resolve periodontal inflammation in rat extraction sockets.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.5
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• pp.375-379
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• 2011

Introduction: This study examined the effect of autogenous tooth bone used as a graft material for bone regeneration in an artificial bony defect of minipigs. Materials and Methods: Four healthy minipigs, weighing approximately 35-40 kg, were used. Four standardized artificial two-walled bony defects, 5 mm in length and depth, were made on the bilateral partial edentulous alveolar ridge on the mandible of minipigs, and autogenous tooth bone was augmented in the right side as the experimental group. On the other hand, only alloplastic bone graft material HA was grafted with the same size and manner in the left side as the control group. All minipigs were sacrificed at 4 weeks after a bone graft and evaluated histologically by Haematoxylin-eosin staining. The specimens were also evaluated semi-quantitatively via a histomorphometric study. The percentage of new bone over the total area was evaluated using digital software for an area calculation. Results: All specimens were available but one in the left side (control group) and two in the right side (experimental group) were missing during specimen preparation. The amount of bone formation and remodeling were higher in all experimental groups than the control. The mean percentage area for new bone in the experimental and control groups was $43.74{\pm}11.96%$ and $30.79{\pm}2.93%$, respectively. Conclusion: Autogenous tooth bone is a good alternative to autogenous bone with the possible clinical feasibility of an autogenous tooth bone graft in the reconstruction of bony defects.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.3
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• pp.120-126
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• 2013

Objectives: This study sought to elucidate the effect of autogenous tooth bone material by experimenting on minipig's maxillary sinus and performing histological and histomorphometric analyses. Materials and Methods: Five 18-24 month-old male minipigs were selected, and right maxillary sinuses were grafted with bone graft material made of their respective autogenous teeth extracted eight weeks earlier. The left sides were grafted with synthetic hydroxyapatite as control groups. All minipigs were sacrificed at 12 weeks after bone graft, which was known to be 1 sigma (${\sigma}$) period for pigs. Specimens were evaluated histologically under a light microscope after haematoxylin-eosin staining followed by semi-quantitative study via histomorphometric analysis. The ratio of new bone to total area was evaluated using digital software for calculation of area. Results: All specimens were available, except one on the right side (experimental group), which was missing during specimen preparation. This study demonstrated new bone at the periphery of the existing bone in both groups, showing evidence of bone remodeling, however, encroachment of new bone on the central part of the graft at the 1 ${\sigma}$ period was observed only in the autogenous tooth bone group (experimental group). Histomorphometric analysis showed more new bone formation in the experimental group compared to the control group. Although the difference was not statistically significant (P>0.05), the mean percentage area for new bone for the experimental and control groups were $57.19%{\pm}11.16%$ and $34.07%{\pm}13.09%$, respectively. Conclusion: The novel bone graft material using autogenous tooth is a good alternative to autogenous bone, comparable to autogenous bone, and outperforming synthetic hydroxyapatite bone graft materials in terms of bone regeneration capacity. Augmentation with autogenous tooth bone materials will reduce donor site morbidity without hampering the safety of the autogenous bone graft.

• BMB Reports
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• v.41 no.4
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• pp.322-327
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• 2008

In this study, we compared the gene expression profiles of non-syndromic hyperplastic dental follicle (HDF) fibroblasts and normal dental follicle (NDF) fibroblasts using cDNA micro-arrays, quantitative PCR, and immunohistochemical staining. Microarray analysis showed that several collagens genes were upregulated in the HDF's, including collagen types I, IV, VIII, and XI and TIMP-1, -3, and -4 (fold ratio > 2.0). In contrast, the expression of MMP-1, -3, -10, and -16 together with IL-8 was more than two fold downregulated. The differential expression of the genes encoding alkaline phosphatase, MMP-1, -3, -8, and IL-8 was confirmed by quantitative RT-PCR, while that of 24 HDFs and 18 NDFs was confirmed by immunohistochemical analysis. However, HDFs showed stronger expression of MMP-3 than NDFs (P < 0.001). Collectively, these results indicate that defective regulation of MMPs mediating connective tissue remodeling may be responsible for abnormal tooth eruption.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.1 no.1
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• pp.50-57
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• 1992

Intrinsic discoloration of permanent anterior teeth is a continuing esthetic problem. Tetracycline ingested during amelogenesis has long been recognized as predisposing factor in intrinsic staining. Methods for restoring original tooth color have included (1) complete PFM crown coverage (2) porcelain laminate veneers (3) direct bonding of composite resin, and (4) bleaching. In the case of tetracycline-stained upper anterior teeth, We authors, obtained the satisfactory results by means of gingivectomy, preliminary bleaching and porcelain laminate veneer restoration.

• Journal of dental hygiene science
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• v.13 no.2
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• pp.191-196
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• 2013

The purpose of this study was to evaluate the tooth brightening of whitening dentifrice and to determine the tooth stain level over 20 days depending on beverages that have various pH values after using whitening dentifrice. Thirty teeth were randomly divided into two groups. Group 1 was provided with a whitening dentifrice for 3 minutes and group 2 was treated with a control dentifrice for 3 minutes thrice a day for four weeks. All teeth were photographed using a digital imaging system under a stereomicroscope (magnification, ${\times}10$). After four weeks, the ten teeth were immersed in the tea solution, another of ten teeth were immersed in the orange juice and the other of the teeth were immersed in the coffee solution. Three solutions were renewed each day for the appropriate groups. Stain development was monitored under a stereomicroscope daily over 20 days period by immersion of teeth in a tea, juice, coffee solution at room temperature ($25^{\circ}C$) in individual container. Whitening dentifrice gave a statistically higher value of overall color change as compared to control dentifrice after 21 days (p<0.05). Stain level of whiten tooth immersed in orange juice was the grestest overall color change, but there was not statistically significant difference (p>0.05). On the other hand, stain level of whiten tooth immersed in coffee and green tea showed a statistically significant difference after 15 days and 5 days, respectively (p<0.05). Tooth immersed in green tea was higher negative value than control dentifrice. The tooth using whitening dentifrice was shown to be effectively whiter color than control dentifrice. However, stain level by orange juice, coffee and green tea has a strong staining effect.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.188-196
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• 2020

Objective: Preservation of the periodontal ligament (PDL) is vital to the success of tooth autotransplantation (TAT). Increased PDL volumes and facilitated tooth extraction have been observed upon orthodontic preloading. However, it is unclear whether any changes occur in the expressions of bone biomolecules in the increased PDL volumes. This study aimed to determine the expressions of runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), receptor activator of nuclear factor kappa-B ligand (RANKL), and osteoprotegerin (OPG) in PDL upon preloading. Methods: Seventy-two premolars from 18 patients were randomly assigned to experimental groups that received a leveling force for 1, 2, or 4 weeks or to a control unloaded group. Following extraction, PDL volumes from 32 premolars of eight patients (21.0 ± 3.8 years) were evaluated using toluidine blue staining. The expressions of the biomolecules in the PDL from 40 premolars of ten patients (21.4 ± 4.0 years) were analyzed via immunoblotting. Results: The median percentage of stained PDL was significantly higher at 2 and 4 weeks after preloading than in the unloaded condition (p < 0.05). The median RUNX2 and ALP expression levels were significantly higher at 2 and 4 weeks after preloading than in the unloaded condition (p < 0.05), whereas the median RANKL/OPG ratios were significantly higher at 1 and 4 weeks after preloading (p < 0.05). Conclusions: Orthodontic preloading for 4 weeks enhances PDL volumes as well as the expressions of RUNX2, ALP and the RANKL/OPG ratio in the PDL, suggesting this loading period is suitable for successful TAT.