• The korean journal of orthodontics
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• v.38 no.3
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• pp.187-201
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• 2008

Objective: The aim of this study was to determine whether cortical punching stimulates the expression of matrix metalloproteinase-1, -8, and -13 in orthodontic tooth movement in rats. Methods: A total of 32 male sprague-dawley rats at 15 weeks old were divided into two groups of 16 rats each, to form the tooth movement with cortical punching (TMC) group and tooth movement only (TM) group. A total of 20 gm of orthodontic force was applied to rat incisors to cause experimental tooth movement. Cortical punching was performed on the palatal side near the central incisor with a 1.0 mm width microscrew in the TMC group. The duration of tooth movement was 1, 4, 7, and 14 days. Results: Measurements of the mRNA expression were selected as the means to determine the identification of expression of MMP-1, -8, and -13. In the TMC group, the expression of collagen type I was greater than that of the TM group from day 4 to day 14. Expression of TIMP-1 in the TM group was greater than that of the TMC group in the pressure side of PDL and alveolar bone cell at day 4. In the TMC group, TIMP-1 was expressed at the osteoclast, but not at the tooth surface of the TM group at day 14, Maximum induction of the mRNA of MMP-1 was observed on day 4 in the TMC group, but it was observed on day 7 in the TM group. MMP-8 mRNA of the TMC group was twice greater than that of the TM group at f days. In the TMC group, maximum induction of MMP-13 mRNA was observed on day 1. Conclusions: These findings suggested that cortical punching can stimulate remodeling of PDL and alveolar bone connective tissues during experimental orthodontic tooth movement in rats.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.379-388
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• 2002

For the success of dental implant, accurate radiographic evaluation is prerequisite for planning the location of the osseointegrated implants and avoiding injury to vital structures. CT/MPR(computed tomography/multiplanar reformation) shows improved visualization of inferior alveolar canal. In order to obtain cross-sectional images parallel to the teeth, the occlusal plane is used to orientate for the axial plane. If the direction of axial plane is not parallel to the occlusal plane, the reformatted cross-sectional scans will be oblique to the planned fixture direction and will not show the actual dimension of the planned fixture's location. If the available bone height which measured in the cross-sectional view is much greater than the actual available bone height, penetration of canal may occur. The aim of this study is to assess the effect of the axial plane to measurement of available bone height for dental implant in computed tomography of the mandible. 40 patients who had made radiographic stents and had taken CT were selected. The sites that were included in the study were 45 molar regions. In the central panoramic scan, the length from alveolar crest to superior border of inferior alveolar canal(available bone height, ABH) was measured in direction of reformatted cross-sectional plane(uncorrected ABH). Then, length from alveolar crest to superior border of canal was measured in direction of stent(corrected ABH). The angle between uncorrected ABH and corrected ABH was measured. From each ABH, available fixture length was decided by $Br{{\aa}}nemark$ system. The results were following ; the difference between two ABHs was statistically significant in both first and second molar(p< 0.01). The percentage of difference more than 1 mm was 8.7% in first molar and 15.5% in second molar. The percentage of difference more than 2 mm was 2.0% in first molar and 6.6% in second molar. The maximum value of difference was 2.5 mm in first molar and 2.2 mm in second molar. The correlations between difference of 2 ABHs and angle was positive correlations in both first and second molar. The correlation coefficient was 0.534 in first molar and 0.728 in second molar. The second molar has a stronger positive correlation. The percentage of disagreement between 2 fixture lengths from two ABHs was 24.4% in first molar and 28.9% in second molar.

• Journal of Periodontal and Implant Science
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• v.32 no.2
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• pp.371-378
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• 2002

In this study, 40 hypersensitive teeth of 19 patients were investigated. The procedures performed were as follows: Before desensitization, EPT at occlusal third of buccal surface was done for the evaluation of pulp vitality and the EPT value was recorded for the reference value. And mechanical and thermal test was executed for the test of hypersensitivity. If the tooth responded to the above tests, we did EPT at the exposed surface, using toothpaste as a electrolite medium and recorded the EPT value at patient's response. After the tests had been done, desensitization procedures with Gluma(R) Desensitizer were performed according to the manufacturer's instructions. After desensitization, the same tests except EPT at occlusal third were repeated. All the 40 teeth responded positive before desensitization and negative after desensitization procedures. The EPT value at occlusal third ranged from 31 to 65 (48.9${\pm}$7.2). Before desensitization 34 teeth responded at EPT value of 2 and the remaining 6 teeth was in the range of 17 to 25. After desensitization all 40 teeth responded from 12 to 27 (19.6${\pm}$3.5). The 6 teeth responded at greater number than 2 before desensitization was in the range of 18 to 23. Within the limitations of this study we can conclude that: When a tooth with dentinal hypersensitivity responds to mechanical and thermal stimulation, the tooth shows very low resistance to electricity at the exposed surface while when a tooth is desensitized and doesn't show respond to mechanical and thermal stimuli, the tooth shows increased level of resistance to electric stimulation at the exposed surface. EPT can be used for the diagnosis of dentinal hypersensitivity. Furthermore EPT will be useful to evaluate the outcome of desensitization procedures. However, EPT is not a valid tool for measuring dentinal hypersensitivity.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.703-721
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• 1998

In order to observe the effects of Nicotine and NNK on cultured human gingival fibroblast, several factors were examined including mutagenicity, the number of cells attached culture plate surface through MTT test, the abundance of collagen & collagenase in mRNA level and collagenolytic activity in extracellular matrix. The results were as follows; 1. Regardless of the co-existence of S9, Nicotine did not show the mutagenicity by itself and NNK by itself showd the same result; However, dose related mutagenicity was shown in NNK with S9. 2. The number of fibroblasts attached cultured plate surface was measured by MTT procedure. The number of cells in Non-smokers increased at all time periods as compared to those of smoker. 3. Non-smoker's fibroblast treated by NNK or Nicotine was dosedependently dosedependently decreased in the number of cells when compared to untreated control. In higher dose, Nicotine showed the cellular toxicity, but NNK did not. 4. No change in the abundance of mRNA for pro${\alpha}1$ and pro${\alpha}2$ was shown in Nicotine treated group but in gingival fibroblasts following treatment with NNK, the abundance of mRNA for pro${\alpha}1$, but not pro${\alpha}2$ collagen was decreased. 5. The abundance of mRNA for collagenase was decreased when NNK was treated but no change occurred in Nicotine treated group. 6. The effect of NNK and Nicotine in collagenolytic activity showed that, collagenase activity exclusively react to type I collagen, was increased in both group, but gelatinase exclusively react to type IV collagen was not influenced at all. Collagenase activity of smoker's fibroblast was also increased as much as Nicotine and NNK group. The findings suggest that both of Nicotine and NNK lead gingival fibroblast to decrease in the abundance of collagen. And it seems to be that Nicotine and NNK have independent pathway toward the gingival fibroblast.

• Journal of Periodontal and Implant Science
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• v.28 no.4
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• pp.659-678
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• 1998

In the present study, oligonucleotide probes based on 16S rRNA were taken to investigate the diversity of oral spirochetes without culture method. This is the first study that revealed oral spirochetes of both presently cultivable and uncultured oral spirochetes in Korean adult periodontitis patients. Subgingival plaque samples were taken from diseased sites(probing depth ${\geq}6\;mm$, experimental group, n=116) and healthy sites(probing depth${\leq}3mm$, control 1 group, n=28) in 29 patients with adult periodontitis, and from 20 periodontally healthy subjects(probing depth${\leq}3mm$, control 2 group, n=100). Following being examined under phase-contrast microscope, all samples were submitted to dot-blot hybridization after polymerase chain reacton with eubacterial primers. 5 species-specific probes(TVIN, TDEN, TMAL, TSOC, and TPEC) and 7 group-specific probes(TRE I, TRE II, TRE III, TRE IV, TRE V, TRE VI, and TRE VII) were used one by one for the identification of both cultivable and so far uncultivable oral spirochetes. All probes were labeled with digoxigenin(DIG)-ddUTP and detected by chemilumininescence. The following results were obtained. 1. Under phase-contrast microscope, 91.37% and 14.28% of oral spirochetes were observed in the experimental and control 1 groups, respectively. None of oral spirochetes were observed in control 2 group. 2. With universal probe, 98.27%, 46.42%, and 22.0% of oral spirochetes were observed in experimental, control 1, and control 2 groups, respectively. 3. With specific probe, 95.68%, 35.71%, and 19.0% of oral spirochetes were observed in experimental, control 1, and control 2 groups, respectively. 4. With species-specific probes, T. socranskii were recovered in a high percentage of sites(81.89%) examined, followed by T. maltophilum(50.0%), T. vincentii(36.20%), T. denticola(13.79%), respectively. With group- specific probes, TRE IV was recovered in a high percentage of sites(85.34%) examined, followed by TRE II(77.58%), TRE I(56.89%), TRE III(25.86%), TRE VI(5.17%), and TRE V(2.58%), respectively. 5. T. vincentii were only observed in the diseased sites, not in the healthy sites. 6. Neither T. pectinovorum nor group VII oral spirochetes were observed in any sites. The findings warrant further investgations of the recovered spirochetes to elucidate the possible associations of oral spirochetal prevalence in race and types of periodontitis, pathogenesis of T. vincentii and the possible distributional change of oral spirochetes before and after treatments.

• Journal of Periodontal and Implant Science
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• v.24 no.2
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• pp.321-339
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• 1994

The cytokines released by osteoblasts induce bone resorption via the differentiation of osteoclast precursors. In this process, $interleukin-1{\beta}$($IL-1{\beta}$)-induced bone resorption is mediated by granulocyte macrophage-colony stimulation factor(GM-CSF), interleukin-6 (IL-6), and tumor necrosis factor ${\alpha}$($TNF-{\alpha}$) released from osteoblasts. Since these cytokines (GM-CSF, IL-6, $TNF-{\alpha}$) are produced by not only osteoblasts but also monocytes, and interleukin-10(I1-10) inhibits the secretion of these cytokines from monocytes, it may be speculated that IL 10 could modulate the production of GM-CSF, IL-6, and $TNF-{\alpha}$ by osteoblasts, then control $IL-1{\beta}-induced$ bone resorption. Therefore, the aims of the present study were to examine the effects of IL-10 on bone resorption. The sixten or seventeen-day pregnant ICR mice were injected with $^{45}Ca$ and sacrificed one day after injection. Then fetal mouse calvaria prelabeled with $^{45}Ca$ were dissected out. In order to confirm the degree of bone resorption, mouse calvaria were treated with Lipopolysaccharide(LPS), $TNF-{\alpha}$, $IL-1{\alpha}$, IL-8, $IL-1{\beta}$, and $IL-1{\alpha}$, Then, IL-10 and $interferon-{\gamma}$ ($IFN-{\gamma}$) were added to calvarial medium, in an attempt to evaluate the effect of $IL-1{\beta}-induced$ bone resorption. In addition, osteoclasts formation in bone marrow cell cultures, and the concentration of IL-6, $TNF-{\alpha}$, and GM-CSF produced from mouse calvarial cells were investigated in response to $IL-1{\beta}$ alone and simultaneously adding f $IL-1{\beta}$ and IL-10. The degree of bone resorption was expressed as the ratio of $^{45}Ca$ release(the treated/the control). The osteoclasts in bone marrow cultures were indentified by tartrate resistant acid phosphatase(TRAP) stain and the concentration of the cytokines was quantified using enzyme linked immunosorbent method. As results of these studies, bone resorption was induced by LPS(1 ng/ml ; the ratio of $^{45}Ca$ release, $1.14{\pm}0.07$). Also $IL-1{\beta}$(1 ng/ml), $IL-1{\alpha}$(1 ng/ml), and $TNF-{\alpha}$(1 ng/ml) resulted in bone resorption(the rations of $^{45}Ca$ release, $1.61{\pm}0.26$, $1.77{\pm}0.03$, $1.20{\pm}0.15$ respectively), but IL-8 did not(the ratio of $^{45}Ca$ release, $0.93{\pm}0.21$). The ratios of $^{45}Ca$ release in response to IL-10(400 ng/ml) and $IFN-{\gamma}$(100 ng/ml) were $1.24{\pm}0.12$ and $1.08{\pm}0.04$ respectively, hence these cytokines inhibited $IL-1{\beta}$(1 ng/ml)-induced bone resorption(the ratio of $^{45}Ca$ release $1.65{\pm}0.24$). While $IL-1{\beta}$(1 ng/ml) increased the number of TRAP positive multinulcleated cells in bone marrow cultures($20{\pm}11$), simultaneously adding $IL-1{\beta}$(1 ng/ml) and IL-10(400 ng/ml) decreased the number of these cells($2{\pm}2$). Nevertheless, IL-10(400 ng/ml) did not affect the IL-6, GM-CSF, and $TNF-{\alpha}$ secretion from $IL-1{\beta}$(1 ng/ml)-activated mouse calvarial cells. From the above results, it may be suggested that IL-10 inhibites $IL-1{\beta}-induced$ osteoclast differntiation and bone resorption. However, the inhibitory effect of IL-10 on the osteoclast formation seems to be mediated not by the reduction of IL-6, GM-CSF, and $TNF-{\alpha}$ production, but by other mechanisms.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.747-753
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• 2003

면역글로불린의 Fc 부분에 대한 수용기인 $Fc{\gamma}R$는 세균에 대한 인식, 결합과 포식작용과정에서 중요한 역할을 한다. 이 $Fc{\gamma}R$에서 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb의 유전자 다형성이 치의학 분야에서 연구되고 있다. $Fc{\gamma}R$IIa에서는 두 번째 세포외 면역글로불린 유사 영역의 131번째 아미노산에서 아르기닌($Fc{\gamma}R$IIa-R131) 혹은 히스티딘($Fc{\gamma}R$IIa-H131)을 갖고 있으며, $Fc{\gamma}R$IIIa에서는 두번째 세포외 영역의 158번째 아미노산이 발린($Fc{\gamma}R$IIIa-158V) 혹은 페닐알라닌($Fc{\gamma}R$IIIa-158F)을 갖고 있다. $Fc{\gamma}R$IIIb에서는 첫 번째 세포외 면역글로불린 유사영역의 4개의 아미노산의 유전자 다형성으로 인해서 $Fc{\gamma}R$IIIb-NA1과 $Fc{\gamma}R$IIIb-NA2의 두가지 유전자 다형성을 보이고 있다. 이번 연구는 치주적으로 건강한 한국인에서 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb에 대한 유전자형의 분포를 조사하고자 한 것으로 서울대학교 치과병원에 근무하는 치과의사, 치과위생사, 간호조무사 및 서울대학교 치과대학 4학년 학생 중 치주낭 깊이와 부착소실이 4mm 이하인 치주적으로 건강한 한국인 65명을 대상으로 하였다. $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb의 유전자 다형성은 분리한 DNA에 각 대립유전자에 특이성을 지닌 primer를 넣고 PCR(polymerase Chain Reaction)법을 이용하여 증폭시킨후 전기영동법을 이용하여 각 대립유전자의 존재를 확인함으로써 결정하였다. $Fc{\gamma}R$IIa의 유전자 다형성은 R/R131, R/H131, H/H131의 유전자형에 대하여 각각 7.7%, 38.5%, 53.8%의 분포를 보였으며, $Fc{\gamma}R$IIIa의 158V/V, 158V/F, 158F/F 유전자형에 대하여 각각 7.7%, 35.4%, 56.9%의 분포를 보였다. 또한 $Fc{\gamma}R$IIIb의 NA1/NA1, NA1/NA2, NA2/NA2 유전자형은 각각 33.9%, 53.8%, 12.3%의 분포를 보였다. 이를 바탕으로 각 대립유전자의 발생빈도 계산한 결과 $Fc{\gamma}R$IIa의 R131과 H131이 26.9% 73.1%로 나타났으며, $Fc{\gamma}R$IIIa의 158V, 158F의 유전자형이 25.4%, 74.6%로 나타났다. $Fc{\gamma}R$IIIb의 NA1, NA2 유전자형의 발생빈도는 60.8%, 29.2%로 나타났다. 이번 연구는 치주적으로 건강한 한국인에서의 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb에 대한 유전자형의 분포를 조사한 것으로, 이후 치주질환자의 유전자형 분포와의 비교로 치주질환과 $Fc{\gamma}R$IIa, $Fc{\gamma}R$IIIa, $Fc{\gamma}R$IIIb의 유전자다형성과의 관련성에 관한 추가적인 연구가 필요할 것으로 여겨진다.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.170-178
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• 2011

The purpose of this study was to assess the prevalence of periodontopathic bacteria and resistance determinants from oral biofilm of children. Subgingival dental plaque was isolated from 87 healthy children, and PCR was performed to determine the presence of 5 periodontal pathogens including P. gingivalis, T. forsythia, T. denticola, F. nucleatum, A. actinomycetemcomitans, and nine resistance genes including tet(Q), tet(M), ermF, aacA-aphD, cfxA, $bla_{SHV}$, $bla_{TEM}$, vanA, mecA. 1. The prevalence of F. nucleatum, T. forsythia. and P. gingivalis was 95.4%, 55.2%, and 40.2%, respectively. In addition. the prevalence of A. actinomycetemc omitans was 5.7%, while T. denticola was 3.4%. 2. In analysis of antibiotic resistance determinants. cfxA, $bla_{TEM}$ and tet(M) were detected in all the samples tested. It was also found that the prevalence of tet(Q) showing tetracycline resistance. $bla_{SHV}$ associated with resistance to ${\beta}$-lactams, ermF exhibiting erythromycin resistance, and, vanA resulting vancomycin resistance was 88.5%, 29.9% 87.4%, and 48.5%, respectively. The aacA-aphD gene showing resistance to aminoglycosides and mecA gene harboring methicillin resistance exhibited the lowest prevalence with 9.2%. 3. In a correlation analysis between periodontopathic pathogens and antibiotic resistance determinants, it was found that there was a significant correlation between T. forsythia and $bla_{SHV}$. Also, P. gingivalis and vanA showed a correlation. Finally, tet(Q) and ermF showed a significant correlation (phi: 0.514) while mecA and vanA also showed a correlation(phi: 0.25).

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.1
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• pp.119-125
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• 2009

Fusion and gemination are irregularities in tooth development. It is often difficult to differentiate between gemination and fusion and it is common to refer to these anomalies as 'double teeth'. The deciduous teeth are most commonly involved, but in 0.1% of cases permanent teeth are affected, in which case aesthetic, funtional and periodontal problems can result. Double teeth present great difficulties in management and required a multidisciplinary approach. The central groove on the labial and palatal surfaces of a double tooth is extremely prone to caries, therefore early 'fissure sealing' is essential. In permanent dentition, surgical separation of fused teeth may be possible with subsequent orthodontic alignment and restorative treatment as needed to reshape the crown. Reshaping or reduction of a double tooth with a single canal may be attempted by modifying the appearance of the labial groove and the use of composite tints but is often impossible and extraction may be the only alternative. Orthodontic treatment and prosthetic replacement is then required. Implants may be an option for adolescents. The present study describes three clinical cases of double teeth in the position of the maxillary permanent incisors. The first case demonstrates an example of multidisciplinary care including surgical intraoral hemisection, root canal therapy, restorative and orthodontic treatment. The second and third cases describe the external and internal morphology of the two fused teeth by means of three dimensional dental computer tomography.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.1
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• pp.45-58
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• 2013

The purpose of this study was to analyze the area of occlusal contact points using visual method. One subject was selected who had Angle Class I, normal dentition, without dental caries, periodontal disease and temporomandibular disorders. Forty times PVS impressions were taken and 10 pairs casts were fabricated using dental super hard stone. After mounting the casts with customized loading apparatus, 78.9kg/f force was loaded as a maximum biting force. In T-Scan method, occlusal contact points measurement was repeated twice. Then, using Photoshop program (Adobe photoshop CS3, Adobe. San Jose, USA), the pixels which indicated occlusal contact points by color was recognized, and the distribution of recognized pixels were calculated to area. In Add picture method, polyether bite material applied to the occlusal surface of the casts. Then, the image of the translucent areas was recorded and classified $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area by the amount of transmitted light. To acquire occlusal surface, the numbers of pixels from the photograph of the contact area indicated cast converted to $mm^2$. The mean occlusal contact area by two methods was statistically analyzed (paired t-test). Part of the red and pink area in T-Scan image were almost equivalent to the $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$, $0{\sim}60{\mu}m$ area in Add picture image. The distribution of occlusal contact points were similar, but the average area of occlusal contact points was wider in T-scan image (P<.05). Pink and red area in T-scan image was wider than $0{\sim}10{\mu}m$, $0{\sim}30{\mu}m$ area in Add picture image (P<.05), but similar to $0{\sim}60{\mu}m$area in Add picture image (P>.05). Occlusal contact points in T-scan image did not indicate real occlusal contact points. Occlusal contact areas in T-scan method were enlarged results comparing with those in Add picture method.