• Journal of the korean academy of Pediatric Dentistry
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• v.11 no.1
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• pp.131-143
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• 1984

150 rats weighting about 150gm were devided into control group of 80 and experimental group of 70. Control group was subdivided into the irradiated vitamin D injection group and X-ray irradiated group. Experimental group was given 2.0mg ergocalciferol by four intramuscular injection prior to X-ray irradiation with single 800 rads and 1,500 rads respectively. Experimental animals from each group was sacrificed after 1, 3, 7, 14, and 28 days and their incisors were investigated by histopathological examination. The results were as follows; 1. In the irradiated groups, it showed dentin hypoplasia and formation of dentinoid substance caused by degeneration of odontoblast at the early stage. Especially, 1,500 rads group which was severely effected showed formation of osteoid dentin at the apical portion and severe injuries of dental papilla at the first week. 2. In the vitamin D2 administration group, it showed thinned dentin layer at the early stage but, taking time, predentin and dentin layer was thickened. At the fourth week, dentin was chiefly composed of interglobular dentin, especially in the lingual portion. 3. Using in combination of overdose vitamin D2 administration and X-ray irradiation, it effected severely odontoblast, undifferentiated mesenchymal cells around tooth germ and pulp tissue. At the early stage, dentin layer was thinned but, taking time, it was thickened and composed of interglobular dentin caused by calcification of predentin layer. 4. In 800 rads irradiation after the overdose vitamin D2 administration, it showed formation of osteoid dentin in the lingual portion at the first week. In the 1,500 rads irradiation after the overdose vitamin D2 administration, it showed formation of osteoid dentin and degeneration of ameloblast in both buccal and lingual portion at the first week, and enamel hypoplasia caused by edema and loss of polarity of ameloblasts at the second week. 5. By the entire experiment, the overdose vitamin D2 administration and X-ray irradiation effected severely odontoblasts, undifferentiated mesenchymal cells of dental papilla, and primitive cells of tooth germ among the dental tissue. Especially using combination of overdose vitamin D2 administration and X-ray irradiation also effected ameloblasts, resulting in enamel hypoplasia.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.6
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• pp.438-444
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• 2021

Objectives: Loss of the interdental papilla is multi-factorial and creates a multitude of problems. Autogenous connective tissue/biomaterial-based regeneration has been attempted for decades to reconstitute the black space created due to the loss of papilla. The aim of this present study was to regenerate papillary recession defects using an amnion-chorion membrane (ACM) allograft and to evaluate the clinical outcome up to six months postoperatively. Materials and Methods: Twenty patients with 25 Nordland and Tarnow's Class I/II interdental papillary recession defects were treated with ACM and coronal advancement of the gingivo-papillary unit via a semilunar incision on the labial aspect followed by a sulcular incision in the area of interest. A photographic image analysis was carried out using the GNU Image Manipulation software program from the baseline to three and six months postoperatively. The black triangle height (BTH) and the black triangle width (BTW) were calculated using the pixel size and were then converted into millimeters. The mean and standard deviation values were determined at baseline and then again at three and six months postoperatively. The probability values (P<0.05 and P≤0.01) were considered statistically significant and highly significant, respectively. An analysis of variance and post hoc Bonferroni test were carried out to compare the mean values. Results: Our evaluation of the BTH and BTW showed a statistically and highly significant difference from the baseline until both three and six months postoperatively (P=0.01). A post hoc Bonferroni test disclosed a statistically significant variance from the baseline until three and six months postoperatively (P<0.05) and a non-significant difference from three to six months after the procedure (P≥0.05). Conclusion: An ACM allograft in conjunction with a coronally advanced flap could be a suitable minimally invasive alternative for papillary regeneration.

• The Journal of the Korean dental association
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• v.16 no.3 s.106
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• pp.193-195
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• 1978

The author observed the effect of x-ray irradiation on the tooth germ development of the rat fetuses. The lower right abdomen of the pregnant rats were exposed to x-ray irradiation (400 rads) on 9½th day of qestation. At 18½th day of qestation, the fetuses were removed from their mothers and histological sections of molar region were prepared. The results were as folows: 1. In the experimental fetuses, no significant changes appeared in the histological aspects of the enamel pulp, except the poor development of the innerenamel epithelium in the cusp region. 2. Pulp cells of cusp region in the irradiated fetuses were not differentiated to odontoblasts, The arrangement and population of pulp cells showed marked regional differences in the dental papilla. 3. Developmental features of dental follicle of irradiated fetuses were similar with controls.

• The Journal of the Korean dental association
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• v.51 no.11
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• pp.586-594
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• 2013

The critical factors affecting the esthetics of anterior implants can be summarized as following: 1) Correct positioning of implant fixture 2) Enough amount of alveolar bone 3) Optimum volume of soft tissue. The position of implant is probably the most important factor in obtaining esthetic treatment outcome. The 3-dimensional orientation of implant is determined by the position on the alveolar ridge and its direction. Clinicians often try to mimic natural teeth when fabricating restorations. During the course of esthetic diagnosis and treatment, however, one should not forget to consider the correlation between facial pattern, lips, gingiva, alveolar ridge, as well as remaining dentition. Since anterior region is biologically unfavorable when compared with posterior region, one minor discrepancy in positioning of implant can cause esthetically undesirable treatment outcome. If one understands the biological and prosthetic meaning of implant's 3-dimensional position, he or she can achieve superior esthetic outcome in anterior region.

• Journal of Periodontal and Implant Science
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• v.41 no.5
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• pp.248-252
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• 2011

Purpose: The anterior region is a challenge for most clinicians to achieve optimal esthetics with dental implants. The provisional crown is a key factor in the success of obtaining pink esthetics around restorations with single implants, by soft tissue and inter-proximal papilla shaping. Provisional abutments bring additional costs and make the treatment more expensive. Since one of the aims of the clinician is to reduce costs and find more economic ways to raise patient satisfaction, this paper describes a practical method for chair-side fabrication of non-occlusal loaded provisional crowns used by the authors for several years successfully. Methods: Twenty two patients (9 males, 13 females; mean age, 36,72 years) with one missing anterior tooth were treated by using the presented method. Metal definitive abutments instead of provisional abutments were used and provisional crowns were fabricated on the definitive abutments for all of the patients. The marginal fit was finished on a laboratory analogue and temporarily cemented to the abutments. The marginal adaptation of the crowns was evaluated radiographically. Results: The patients were all satisfied with the final appearance and no complications occurred until the implants were loaded with permanent restorations. Conclusions: The use of the definitive abutments for provisional crowns instead of provisional abutments reduces the costs and the same results can be obtained.

• International Journal of Oral Biology
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• v.31 no.4
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• pp.135-140
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• 2006

Temperature signaling can be initiated by members of transient receptor potential (thermo-TRP) channels. Hot and cold substances applied to teeth usually elicit pain sensation. Since odontoblasts constitute a well-defined layer between the pulp and the mineralized dentin, being first to encounter thermal stimulation from oral cavity, they may be involved in sensory transduction process, in addition to their primary function as formation of dentin. We investigated whether thermo-TRP channels are expressed in a odontoblast cell line, MDPC-23. The expressions of thermo-TRP channels were examined using reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry, fluorometric calcium imaging. Analysis of RT-PCR revealed mRNA expression of TRPV1, TRPV2, TRPV4 and TRPM8, but no TRPV3, TRPA1. Immunohistochemical approach failed to detect TRPV1 expression. Whereas the application of 4-phorbol-12,13-didecanoate($10\;{\mu}M$, a TRPV4 agonist), menthol(1 mM, a TRPM8 agonist) and icilin($10\;{\mu}M$, a TRPM8 agonist) produced the enhancement of intracellular calcium concentration, capsaicin($1\;{\mu}M$, a TRPV1 agonist) did not. Our results suggest that subfamily of thermo-TRP channels expressed in odontoblasts may serve as thermal or mechanical transducer in teeth.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.23-29
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• 2009

The ovate pontic was first described by Dewey and Zugsmith in 1933, but used clinically as a clinical alternative for esthetics in the late 1990s. The ovate pontic has been suggested as a more accurate duplication of emergence profile for natural teeth to provide an esthetic, cleanable prosthesis. If the resin temporary prosthesis with the ovate pontic is used during the healing period after the tooth extraction, it is possible to preserve the interdental papilla and eliminate or minimize the black triangle between the teeth. Ultimately it can become a esthetic final restoration without saliva leakage and phonetic discomfort. In this case we tried to treat the maxillary anterior area by the use of the ovate pontic and minimize the loss of the interdental papilla via duplicate the emergence profile of the natural tooth.

• Journal of Periodontal and Implant Science
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• v.53 no.5
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• pp.362-375
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• 2023

Purpose: The aim of this study was to investigate the relationships between gingival thickness (GT) and keratinized gingiva width (KGW), papilla height (PH), and crown ratio (CR) by employing transgingival probing and an intraoral scanner (IOS). Methods: This cross-sectional study examined 360 maxillary anterior teeth from 60 patients. GT was assessed using transgingival probing with an endodontic spreader. KGW, CR, and PH were measured using an IOS. One-way analysis of variance, the Student's t-test, and Spearman correlation coefficients were employed for statistical analysis. Results: Higher GT was significantly associated with thinner KGW in the central region (P=0.019). There was no statistically significant difference in GT between teeth (P=0.06). PH was lower in lateral teeth than in canines (P=0.047), with a PH of 2.99 mm in lateral teeth. The KGW was narrower in canines than in central teeth (P=0.007). A moderate correlation was observed between KGW and PH in the central region (P=0.01), while a weak negative correlation was found between KGW and CR (P=0.043). Conclusions: A moderate negative correlation was found between GT and KGW, as well as between PH and KGW in central teeth. In contrast, a weak negative correlation existed between CR and KGW. The PH (2.99 mm) was lower in lateral teeth than in canines. The traditional paradigm, which suggests a positive correlation between KGW and GT, was reevaluated by measuring KGW using an IOS.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.640-646
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• 2009

In case of luxation injuries, loss of tooth vitality is common. And in case of trauma in the immature permanent teeth, precise diagnosis of pulp necrosis is very difficult. That is because limitation in distinguishing between normal dental papilla in immature permanent teeth, transient apical breakdown(TAB), which is part of normal healing process, and apical radiolucency in pulp necrosis. Especially in non-vital immature permanent tooth, the treatment is complex and requires long time. This clinical case report shows that severely infected immature teeth with periradicular periodontitis can undergo healing and apexogenesis or maturogenesis with no definative treatment or after conservative treatment. In the cases reported, we emphasize the considerable power of regeneration of the tooth, probably due to its large number of undifferentiated mesenchymal cells in the dental papilla, pulp tissue, periodontal ligament tissues. Thus, when endodontic treatment in immature permanent teeth, over instrumentation is not recommend for preserve the apical vital stem cells.

• The Korean Journal of Physiology and Pharmacology
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• v.26 no.1
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• pp.37-45
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• 2022

The aim of the present study was to investigate the physiological role of nicotinamide phosphoribosyltransferase (NAMPT) associated with odontogenic differentiation during tooth development in mice. Mouse dental papilla cell-23 (MDPC-23) cells cultured in differentiation media were stimulated with the specific NAMPT inhibitor, FK866, and Visfatin (NAMPT) for up to 10 days. The cells were evaluated after 0, 4, 7, and 10 days. Cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The mineralization assay was performed by staining MDPC-23 cells with Alizarin Red S solution. After cultivation, MDPC-23 cells were harvested for quantitative PCR or Western blotting. Analysis of variance was performed using StatView 5.0 software (SAS Institute Inc., Cary, NC, USA). Statistical significance was set at p < 0.05. The expression of NAMPT increased during the differentiation of murine odontoblast-like MDPC-23 cells. Furthermore, the up-regulation of NAMPT promoted odontogenic differentiation and accelerated mineralization through an increase in representative odontoblastic biomarkers, such as dentin sialophosphoprotein, dentin matrix protein-1, and alkaline phosphatase in MDPC-23 cells. However, treatment of the cells with the NAMPT inhibitor, FK866, attenuated odontogenic differentiation, as evidenced by the suppression of odontoblastic biomarkers. These data indicate that NAMPT regulated odontoblastic differentiation through the regulation of odontoblastic biomarkers. The increase in NAMPT expression in odontoblasts was closely related to the formation of the extracellular matrix and dentin via the Runx signaling pathway. Therefore, these data suggest that NAMPT is a critical regulator of odontoblast differentiation during tooth development.