• Restorative Dentistry and Endodontics
• /
• 제25권1호
• /
• pp.41-45
• /
• 2000

The purpose of this study was to evaluate the microleakage of compomers. In this in vitro study, class V cavities were prepared on buccal and lingual surfaces of thirty extracted human premolars and molars on cementum cervical margin. The experimental teeth were randomly divided into five groups of six samples (12 surfaces) each, Group 1 : Dyract AP, Group 2 : F2000 compomer(non-etch), Group 3 : F2000 compomer(etch), Group 4 : Elan, Group 5 : Compoglass. The bonding agents and compomer were applied for each group following the manufacturer's instructions. After 500 thermocycling between $5^{\circ}C$ and $55^{\circ}C$, the 30 teeth were placed 1% methylene blue dye for 24 hours then rinsed with tab water. The specimens were embedded in clear resin, then sectioned buccolingually through the center of the restoration with a low speed diamond saw. The dye penetration on each of the specimen was observed with a stereomicroscope. The results of study were statistically analyzed using the Student-Newmann-Kaul' s Test. The results were obtained as follows. 1. All compomer restoration systems did not completely prevent marginal leakage. 2. In enamel margin, F2000 compomer(etch) group showed lower leakage value than other systems. Elan and Compoglass groups showed lower leakage value than Dyract AP and F2000 compomer(non-etch) groups (p<0.05). 3. In cementum margin, F2000 compomer(etch) and F2000 compomer (non-etch) groups showed lower leakage value than other systems. Dyract AP and Elan groups showed lower leakage value than Compoglass group (p<0.05).

• Restorative Dentistry and Endodontics
• /
• 제47권2호
• /
• pp.15.1-15.18
• /
• 2022

This review aimed to characterize the effect of direct restorative material types and adhesive protocols on marginal adaptation and the bond strength of the interface between the material and the proximal dentin/cementum. An electronic search of 3 databases (the National Library of Medicine [MEDLINE/PubMed], Scopus, and ScienceDirect) was conducted. Studies were included if they evaluated marginal adaptation or bond strength tests for proximal restorations under the cementoenamel junction. Only 16 studies met the inclusion criteria and were included in this review. These studies presented a high degree of heterogeneity in terms of the materials used and the methodologies and evaluation criteria of each test; therefore, only a descriptive analysis could be conducted. The included studies were individually evaluated for the risk of bias following predetermined criteria. To summarize the results of the included studies, the type of restorative material affected the test results, whereas the use of different adhesive protocols had an insignificant effect on the results. It could be concluded that various categories of resin-based composites could be a suitable choice for clinicians to elevate proximal dentin/cementum margins, rather than the open sandwich technique with resin-modified glass ionomers. Despite challenges in bonding to proximal dentin/cementum margins, different adhesive protocols provided comparable outcomes.

• 대한치과교정학회지
• /
• 제48권4호
• /
• pp.253-261
• /
• 2018

Objective: Orthodontic root resorption (ORR) due to orthodontic tooth movement is a difficult treatment-related adverse event. Caspases are important effector molecules for apoptosis. At present, little is known about the mechanisms underlying ORR and apoptosis in the cementum. The aim of the present in vivo study was to investigate the expression of tartrate-resistant acid phosphatase (TRAP), caspase 3, caspase 8, and receptor activator of nuclear factor kappa-B ligand (RANKL) in the cementum in response to a heavy or an optimum orthodontic force. Methods: The maxillary molars of male Wistar rats were subjected to an orthodontic force of 10 g or 50 g using a closed coil spring. The rats were sacrificed each experimental period on days 1, 3, 5, and 7 after orthodontic force application. And the rats were subjected to histopathological and immunohistochemical analyses. Results: On day 7 for the 50-g group, hematoxylin and eosin staining revealed numerous root resorption lacunae with odontoclasts on the root, while immunohistochemistry showed increased TRAP- and RANKL-positive cells. Caspase 3- and caspase 8-positive cells were increased on the cementum surfaces in the 50-g group on days 3 and 5. Moreover, the number of caspase 3- and caspase 8-positive cells and RANKL-positive cells was significantly higher in the 50-g group than in the 10-g group. Conclusions: In our rat model, ORR occurred after apoptosis was induced in the cementum by a heavy orthodontic force. These findings suggest that apoptosis of cementoblasts is involved in ORR.

• Journal of Periodontal and Implant Science
• /
• 제26권3호
• /
• pp.701-713
• /
• 1996

The purpose of this study was to evaluate the biocompatibility of the Nd:YAG lased root surface followed by root planing and/or tetracyline-HCI(T.C.-HCI) conditioning. $30,4mm{\times}4mm$ root segments were obtained from unerupted third molars and 21, periodontally involved root segments. The treatment groups were as follows : (1) healthy root cementum surface groups : 1) control(non-treated group), 2) lased only, 3) lased/root planed, and 4) lased/T.C.-HCI. (2) diseased root cementum surface groups : 1) control(root planed only), 2) lased/root planed, and 3) lased/root planed/T.C.-HCI. The specimens were treated with a Nd:YAG laser using a $320{\mu}m$ noncontact optic fiber handpiece with an energy setting of 1.5W($114.6J/cm^2$), 2.0W($152.9J/cm^2$), 5.0W($382J/cm^2$) for one minute. The fiber was held perpendicular to the petri dish(NUNC) 2cm apart in an attempt to expose the entire root segments equally. Human gingival fibroblasts were cultured from explants of normal interdental gingival tissue obtained during third morlar extraction. The attachment assay was performed with third-generation fibroblasts. The numbers of gingival fibroblasts attached to the root surface were counted on each specimen under the light microscope, and were statistically analyzed by the oneway ANOVA followed by Tukey's test in SPSS/PC+programs. The results were as follows : 1) In healthy root cementum surfaces, lased/root planed groups exhibited a significantly increased fibroblast attachment compared to controls, lased only, and lased/T.C.-HCI groups(p<0.05), 2) In diseased root cementum surfaces, laser treatment followed by root planing and/or T.C.HCl groups exhibited a increased tendency of fibroblast attachment compared to root planed only group. The results suggest that laser treatment followed by root planing and/or T.C.-HCl would appear necessary so as to render the root surface biocompatible.

• Journal of Periodontal and Implant Science
• /
• 제24권3호
• /
• pp.633-648
• /
• 1994

Synthetic bone graft materials have been used for the regeneration of periodontal tissue lost due to periodontal disease, but the limitations of these materials had prompted the use of composite grafts. Among those, a composite graft of calcium carbonate(CC) and calcium sulfate(CS) is one of those materials that has not been studied extensively. CC, which is extracted from a natural coral, is known to possess osteoconductive property. SC can play an adjunctive role in the regeneration of bone tissue, and has shown good resorbability and biocompatibility. This study was conducted in order to investigate the effects of CC and CS composite graft to the regeneration of bone in the intrabony defects of dogs. 3-wall intrabony defects ub size of $4mm{\times}4mm{\times}4mm$ were created in the alveolar bone in the premolar areas. Then those defects that were treated with root planning only were designated as control, while the experimental group 1 and 2 each received the CC and CS composite grafts in the ratio of 8 : 2 and 5 : 5 the animals were sacrificed after 8weeks and the specimens were histologically analyzed. The results were as follows ; 1. No inflammation or foreign body reaction were observed in all subjects. CS has not been seen due to complete resorption, and resorption pattern of CC was observed. 2. Significant differences(p<0.05) in new cementum formation were observed between control($1.42{\pm}0.64mm$) and experimental groups(group 1 ; $2.53{\pm}0.94mm$, group 2 ; $2.23{\pm}0.96mm$) but the difference between the two experimental groups was not significant. 3. Significant differences(p<0.01) in new bone formation were observed between control($0.59{\pm}0.55mm$) and experimental groups(group 1 ; $2.27{\pm}0.61mm$, group 2 ; $2.05{\pm}0.56mm$) but the difference between the two experimental groups was not significant. 4. The extent of apical epithelial migration has shown no significant difference between control($1.18{\pm}1.24mm$) and experimental groups(group 1 ; $0.51{\pm}0.54mm$, group 2 ; $0.73{\pm}0.70mm$). 5. The extent of bone formation was generally limited to the extent of cementum formation for all groups, and significant correlation was found in the amount of bone formation and cementum formation in experimental group 1.(Co.=0.86, p<0.01) These results suggest that the composite graft of CC and CS is biocomplatible and effective in the new bone and new cementum formations. In the case of 3-wall intrabony defects of dogs, the composite ratio of 8 : 2 and 5 : 5 had shown no significant differences in the healing.

• Journal of Periodontal and Implant Science
• /
• 제27권2호
• /
• pp.363-377
• /
• 1997

The main goal of periodontal therapy is the regeneration of periodontal tissue which has been lost due to destructive periodontal diseases. Although conventional forms of periodontal therapy show sound clinical results, the healing results in long junctional epithelium. There have been numerous materials and surgical techniques developed for new attachment and bone regeneration. Bone grafts can be catagorized into: autografts, allografts, xenografts and bone substitutes. Synthetic bone substitute materials include hydroxyapatite, tricalcium phosphate, calcium carbonate, and Plaster of Paris. Calcium sulfate has found its use in dental practice for the last 30 years. Recent animal studies suggest that periodontal regeneration in 3 wall intrabony defect may be enhanced by the presence of calcium sulfate. And it is well known that 2 wall & 1 wall defect have less osteogenic potential, So we need to study the effect of calcium sulfate in 1 wall intrabony defect in dogs. The present study evaluates the effects of calcium sulfate on the epithelial migration, alveolar bone regeneration and cementum formation in intrabony defects of dogs. Four millimeter-deep one-wall intrabony defects were surgically created in the mesial aspect of anterior teeth and mesial & distal aspects of premolars. The test group received calcium sulfate grafts with a flap procedure. The control underwent flap procedure only. Histologic analysis following 8 weeks of healing revealed the following results: 1. The lengths of junctional epithelium were: 2.52mm in the control, and 1.89mm in the test group. There was no statistical significance between the two groups. 2. Alveolar bone formation were: 0.61mm in the control, and 1.88mm in the test group. There was a statistically significant difference between the two groups (p<0.05). 3. Cementum formations were: l.lmm in the control, and 2.46mm in the test group. There was a statistically significant difference between the two groups (p<0.05). 4. The length of CT adhesion were: O.97mm in the control, and 0.17mm in the test group. There was no statistically significant differences between the two groups These results suggest that the use of calcium sulfate in intrabony defects has little effect on junctional epithelium migration, but has significant effects on new bone and new cementum formations.

• Restorative Dentistry and Endodontics
• /
• 제35권4호
• /
• pp.273-284
• /
• 2010

본 연구의 목적은 흰 쥐(rat)를 이용하여 미성숙 단계의 치아를 발치 후 즉시 재식 하였을 때 나타나는 치수의 치유 양상을 조직학적으로 관찰하고자 하는 것이다. 생후 4주된 암컷 Sprague-Dawley 계 흰쥐의 상악 우측 제1대구치를 발거 후 원래의 치조골와 내로 위치시켰다. 재식 후 3일째부터 국소적으로 치수 내 염증 소견이 관찰되었으나, 치근 부위에서는 이미 치수의 재혈관화 및 치유가 진행되고 있는 소견이 관찰되었다. 재식 후 5일째부터는 odontoblast-like cell이 관찰되기 시작하였다. 삼차 상아질의 형성은 재식 후 1주째부터 관찰되기 시작하였으며, 2주째부터는 확실히 관찰할 수 있었다. Odontoblast-like cell 및 삼차상아질 형성은 4주째까지도 계속 관찰되었다. 재식 후 4주째에는 bone-like tissue 및 cementum-like tissue이 형성되었음을 관찰하였다. 본 실험을 통하여 흰 쥐 치아 재식 시 석회화 과정은 초기에는 삼차상아질 침착에 의해서 진행되나, 시간이 경과하면서 점차 bone-like tissue 또는 cementum-like tissue가 차지하는 비율이 증가하는 것을 관찰하였다.

• Journal of Periodontal and Implant Science
• /
• 제35권4호
• /
• pp.823-837
• /
• 2005

The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and enamel matrix protein used in conjunction with xenograft. compared to a control group with regards to bone regeneration at the grade III furcation area in beagle dogs. Control group was treated with bovine derived bone $powder(Biocera^{(R)})$, and experimental I group was treated with bovine derived bone powder and Platelet-rich plasma and experimental II group was treated with bovine derived bone powder and Enamel matrix $protein(Emdogain^{(R)})$. The regeneration rate of bone formation was observed and compared histopathologically at 2. 4, and 8 weeks after surgery. The results were as follows: 1. In control group and both experimental groups. inflammatory cells were observed but, new bone formation wasn't. 2. In control group, new cementum on the notch was found in 4 weeks, less mature periodontal ligament when compared to that of experimental group was found and cementum formation was great but, regeneration couldn't be seen in 8 weeks. 3. Experimental I group. new bone formation in the area adjacent to alveolar bone and graft material surrounded by more dense connective tissue were found in 4 weeks. New bone formation up to crown portion was found and periodontal ligament was aligned functionally and cementum more mature. 4. Experimental II group, new bone formation was found under the defect area in 4 weeks and new bone formation around graft material in 8 weeks, too, and there were a number of fibroblasts, blood vessels, acellular cementum, which was less mature when compared to that of experimental I group, and dense collagen fiber like which normal periodontal ligament has in periodontal ligament of experimental II group in 8 weeks. 5. As a result of histologic finding, bone formation rate were 18.0${\pm}$7.87%(control group), 34. 05${pm}$7.25%(experimental I group), 19.33 ${pm}$5.15%(experimental II group) in 4 weeks and 21.89${pm}$1.58%(control group), 38.82${pm}$3.2(experimental I group), 37.65${pm}$9.22%(experimental II group) in 8 weeks. 6. Statistically significant ratio of bone formation was observed in experimental I group in 4 weeks and in experimental II group in 8 weeks. When experimental I group was compared to experimental II group, the ratio of bone formation in experimental I group was higher than that in experimental II group in 4 weeks(p<0.05). This results suggest that platelet-rich plasma showed more new bone formation than enamel matrix protein within 4 weeks. And use of enamel matrix protein in the treatment of periodontal bone defects starts to enhance regeneration after 8 weeks in beagle dogs.

• Journal of Periodontal and Implant Science
• /
• 제28권2호
• /
• pp.249-264
• /
• 1998

The present study evaluates the effects of calcium sulfate and DFDB on alveolar bone regeneration and cementum formation and connective tissue adhesion in intrabony angulated 1 wall defects of dogs. Four millimeter-deep angulated one-wall intrabony defects were surgically created in the mesial & distal aspects of premolars and with flap operaion alone(control group), with calcium sulfate(experimental group 1), with composit graft of 50% calcium sulfate and 50% DFDB(experimental group 2), with DFDB alone(experimental group 3). Histologic analysis following 8 weeks of healing revealed the following results: 1. The lengths of connective tissue adhesion was $1.05{\pm}0.48mm$ in the control, $1.30{\pm}0.67mm$ in the test group I, $0.97{\pm}0.22mm$ in the test group II and $0.93{\pm}0.15mm$ in the test group III. There was no statistical significance between control and all experimental groups. 2. Changes in alveolar bone level was $0.97{\pm}0.27mm$ in the control group, $1.45{\pm}0.42mm$ in the test group I, $2.00{\pm}0.33mm$ in the test group II, $1.88{\pm}0.34mm$ in the test group III. There was no statistically significant difference between control and experimental group I. There was a statistically significant difference between the control and experimental group II,III.(p<0.05). There was no statistically significant difference between all experimental group. 3. Cementum formation was $1.13{\pm}0.17mm$ in the control, $1.78{\pm}0.31mm$ in the test group I, $2.17{\pm}0.38mm$ in the test group II, $2.15{\pm}0.47mm$ in the test group III with statistically significant differences between control group and all experimental group(P<0.05). There was no statistically significant differences between all experimental group. These results suggest that the use of composit graft of 50% calcium sulfate and 50% DFDB and DFDB alone in angulated 1 wall intrabony defects has little effects on connective tissue adhesion, but has significant effects on new bone and new cementum formations.

• Journal of Periodontal and Implant Science
• /
• 제27권3호
• /
• pp.479-493
• /
• 1997

There are various treatment methods including barrier membranes in attaining periodontal regeneration and regaining the function of destructed periodontal tissues due to periodontal disease. Barrier membranes consist of non-Resorbable and resorbable types such as Dura mater and $Guidor^{(R)}$ used in the treatment of intrabony defects and classII furcation defects have been shown to be effectively increased the amount of new bone and cementum.In our study we used premolars with class III furcation defects created by removing the bone 4mm apically from CEJ in adult dogs and placed resorbable membrane Dura mater and $Guidor^{(R)}$ for the test group and flap operation was carried out for the control groups. The effect of membrane on junctional epithelium, alveloar bone, cementum, and gingival connective tisssue in the regeneration and healing potential of periodontal tissues was evaluated and healing results were evaluated histologically and histometrically 8 weeks following the surgical procedure. 1. In the clinical observation, there was no exposure of furcation defects in the control group, whereas slight membrane exposure was noted in the test group. 2. New bone was formed up to the level of the notch in the control group, whereas in the test group new bone formation was observed above the level of the notch. 3. New cementum was formed in both groups of the experiment. 4. The connective tissue observed between the new cementum and new bone in the test group were functionally orientated, compared to the irregular formation of connective tissues found in the control group. 5. Root resorption or ankylosis was not observed in any of the groups 6. The mean and median of the control group were 4.31% and 2.23% and for the Dura mater group were 27.85% and 15.57% respectively. There was no significant difference between Dura mater and the control group. 7. The mean and median of the control group were 4.31% and 2.23% and for the $Guidor^{(R)}$ group were 37.27% and 37.19% respectively. There was a significant difference in these two groups(P$Guidor^{(R)}$ were 37.27% and 37.19%. There was no significant difference between the two test groups. Thus, by using Dura mater and Guidor in classIII furcation defects, the predictable amount of periodontal ligament and alveolar bone regeneration may result.