Abstract This study evaluates periodontal repair and biomaterial reaction following implantation ... more Abstract This study evaluates periodontal repair and biomaterial reaction following implantation of a polyglactin mesh with or without porous resorbable calcium carbonate (RCC) or porous replamineform hydroxyapatite (RHA) in conjunction with reconstructive surgery. Ligature- and surgically-induced interproximal periodontal defects of left and right mandibular premolar teeth in 7 dogs were used. Bilaterally, mesial defects of the 2nd, 3rd and 4th premolar teeth were treated with polyglactin mesh, polyglactin mesh and RHA. or polyglactin mesh and RCC. respectively. The polyglactin mesh, shaped according to the contour of the defect, was adapted to the experimental teeth: its coronal margin positioned immediately apical to the cemento-enamel junction. Gingival flap margins were adapted and sutured to cover the polyglactin mesh completely. Clinical healing was generally uneventful. The dogs were sacrificed to provide block sections for histologic evaluation at 1, 3, 6, 12, 26, 32 and 56 weeks following wound closure. Generally, cementum regeneration was observed beginning at week 6 in all groups. Bone regeneration was observed from week 3 in polyglactin mesh-treated groups, and from week 6 in polyglactin mesh + RCC or polyglactin mesh + RHA treated groups. Bone regeneration appeared enhanced in polyglactin mesh + RCC or polyglactin mesh + RHA treated defects at week 12 and 26, with little difference between the three experimental conditions at week 56. Polyglactin mesh degradation was observed at week 3 and appeared complete at week 12. The RHA did not appear to resorb, while the RCC was gradually replaced by bone from week 3. Within limitations of the study conditions, periodontal regeneration was observed following implantation of a polyglactin mesh with or without RCC or RHA in conjunction with reconstructive surgery. As a conclusion, there seems to be no significant difference in periodontal regeneration after 12 months of healing between the group treated with the membrane only, and the group treated with the membrane and the bone substitution material. Changes in connective fiber orientation over the 1st 12 weeks of healing may suggest that “fibrous encapsulation” observed in earlier studies may only represent a transient stage in periodontal regeneration.
To evaluate the periodontal tissue regenerative effects of a chitosan/collagen sponge applied to ... more To evaluate the periodontal tissue regenerative effects of a chitosan/collagen sponge applied to preclinical one-wall intrabony defects surgically created in beagle dogs. 4 x 4 mm one-wall intrabony defects were surgically created in the bilateral maxillary first and third, and the mandibular second and fourth premolars. The surgical control group received a flap operation only, while the buffer control group was treated afterwards with a phosphate-buffered saline/collagen sponge (CS) and the chitosan group was treated with a chitosan/cs. The subjects were killed 8 weeks after the operation, and a comparative histological examination was performed. The amount of junctional epithelium migration was 2.30+/-1.24 mm in the surgical control group, 1.49+/-1.25 mm in the buffer control group, and 0.26+/-0.59 mm in the chitosan group. A significant difference was exhibited only between the surgical control and the chitosan group (p<0.05). The amount of connective tissue adhesion was 0.68+/-0.60, 1.07+/-0.91, and 0.41+/-0.42 mm in the surgical control, buffer control, and the chitosan group, respectively. The amount of cementum regeneration was 1.42+/-0.49, 1.60+/-0.41, and 3.46+/-0.78 mm in the surgical control, buffer control, and the chitosan group, respectively. A significant difference was seen between the chitosan group and the rest (p<0.01). The amount of alveolar bone regeneration was 1.00+/-0.77, 1.52+/-0.37, and 2.43+/-0.44 mm in the surgical control, buffer control, and the chitosan group, respectively. A significant difference was observed between the chitosan group and the rest (p<0.05). The results demonstrate the beneficial effect of the chitosan/cs on the one-wall intrabony defects of beagle dogs. The inhibited apical migration of epithelium and the increase in the amount of new bone and new cementum suggest the potency of chitosan in inducing periodontal tissue regeneration.
The various methods for regeneration of periodontal tissue that have been developed can be classi... more The various methods for regeneration of periodontal tissue that have been developed can be classified into guided tissue regeneration and bone implantation. Since the implantation materials have shown both deficiencies and merits, dentists have begun exploring the bioactive glass first used in plastic surgery. This paper examines the effectiveness of this new material on periodontal intrabony defects.
Background: Recent interest in naturally based products has increased. Various herbal extracts ar... more Background: Recent interest in naturally based products has increased. Various herbal extracts are known to have a variety of medicinal properties. Among the various natural medicines, safflower seeds have beneficial effects on various bone diseases such as bone fracture, osteoporosis, and osteodysplasia. In addition, they are known to have anti-inflammatory effects. The objective of this study was to evaluate the effect of a safflower seed extract (SSE) on the regeneration of periodontal tissue in a preclinical 1-wall model in dogs.
The objective of this study was to histologically evaluate periodontal healing following flap sur... more The objective of this study was to histologically evaluate periodontal healing following flap surgery in intrabony periodontal defects to determine the influence of the number of bone walls on periodontal regeneration. One-, 2-, and 3-wall intrabony periodontal defects were surgically produced at the proximal aspect of mandibular premolars in either right or left jaw quadrants in six beagle dogs. Mucoperiosteal flaps were positioned and sutured to their presurgery position following defect preparation. The animals were euthanized at 8 weeks post-surgery, and block sections of the defect sites were collected for histologic and histometric analysis. Bone and cementum regeneration was positively correlated to the number of bone walls limiting the intrabony periodontal defects. The junctional epithelium averaged (+/- SD) 1.5 +/- 0.2, 1.2 +/- 0.3, and 0.9 +/- 0.2 mm for the 1-, 2-, and 3-wall defects, respectively, with the 3-wall defects being significantly different from the 1-wall defects (P <0.05). Cementum regeneration averaged 1.2 +/- 0.6, 2.0 +/- 0.6, and 2.8 +/- 0.5 mm for the 1-, 2-, and 3-wall defects, respectively; all groups were significantly different from each other (P <0.05). Bone regeneration averaged 1.5 +/- 0.5, 1.7 +/- 0.6, and 2.3 +/- 0.5 mm for the 1-, 2-, and 3-wall defects, respectively, with the 3-wall defects being significantly different from the 1-wall defects (P <0.05). The results suggest that the number of bone walls is a critical factor determining treatment outcomes in intrabony periodontal defects. One- and 3-wall intrabony defects appear to be reproducible models to evaluate candidate technologies for periodontal regeneration.
Single-stranded genomic DNA of recombinant M13 phages was tested as an antisense molecule and exa... more Single-stranded genomic DNA of recombinant M13 phages was tested as an antisense molecule and examined for its usefulness in high-throughput functional genomics. cDNA fragments of various genes (TNF-a, c-myc, c-myb, cdk2 and cdk4) were independently cloned into phagemid vectors. Using the life cycle of M13 bacteriophages, large circular (LC)-molecules, antisense to their respective genes, were prepared from the culture supernatant of bacterial transformants. LC-antisense molecules exhibited enhanced stability, target specificity and no need for target-site searches. High-throughput functional genomics was then attempted with an LC-antisense library, which was generated by using a phagemid vector that incorporated a unidirectional subtracted cDNA library derived from liver cancer tissue. We identified 56 genes involved in the growth of these cells. These results indicate that an antisense sequence as a part of single-stranded LC-genomic DNA of recombinant M13 phages exhibits effective antisense activity, and may have potential for high-throughput functional genomics.
Ribbon antisense (RiAS) to the hTR RNA, a component of the telomerase complex, was employed to in... more Ribbon antisense (RiAS) to the hTR RNA, a component of the telomerase complex, was employed to inhibit telomerase activity and cancer cell growth. The antisense molecule, hTR-RiAS, combined with enhanced cellular uptake was shown to effectively inhibit telomerase activity and cause rapid cell death in various cancer cell lines. When cancer cells were treated with hTR-RiAS, the level of hTR RNA was reduced by more than 90% accompanied with reduction in telomerase activity. When checked for cancer cell viability, cancer cell lines treated with hTR-RiAS using DNA+Peptide+Lipid complex showed 70-80% growth inhibition in 3 days. The reduced cell viability was due to apoptosis as the percentage of cells exhibiting the sub-G0 arrest and DNA fragmentation increased after antisense treatment. Further, when subcutaneous tumors of a colon cancer cell line (SW480) were treated intratumorally with hTR-RiAS, tumor growth was markedly suppressed with almost total ablation of hTR RNA in the tumor tissue. Cells in the tumor tissue were also found to undergo apoptosis after hTR-RiAS treatment. These results suggest that hTR-RiAS is an effective anticancer reagent, with a potential for broad efficacy to diverse malignant tumors.
The new cholesterol-based cationic lipids B, C, and D with an ether linked spacer were synthesize... more The new cholesterol-based cationic lipids B, C, and D with an ether linked spacer were synthesized by using aminopropyl chain extension with acrylonitrile. The cholesterol-based cationic lipid A with carbamoyl linkage were also synthesized in order to compare the difference in transfection efficiency of the two linkage types. To this end, GFP expression of these cationic lipids was confirmed respectively.
Systematic secondary structure simulation of a target mRNA sequence is shown to be effective for ... more Systematic secondary structure simulation of a target mRNA sequence is shown to be effective for locating a good anti-sense target site. Multiple selected anti-sense sequences were placed in a single molecule. The anti-sense oligonucleotide (oligo) was covalently closed to avoid exonuclease activities and was designated CMAS (covalently closed multiple anti-sense)-oligo. CMAS-oligo was found to be stable, largely preserving its structural integrity after 24 h of incubation in the presence of either exonuclease III or serum. When human c-myb mRNA was targeted by the c-myb CMAS-oligo, expression of the gene was completely abolished. Further, tumour cell growth was inhibited by 82+/-3% as determined by an MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and by 90+/-1% by [(3)H]thymidine incorporation. When a leukaemic cell line K562 was treated with CMAS-oligo, colony formation on soft agarose was also decreased by 93%. In contrast, treatment with a scrambled control oligo did not significantly inhibit leukaemic cell growth. These results suggest that a rational target site search is possible for an anti-sense oligo and that CMAS-oligo can be employed as an effective anti-sense agent with enhanced stability.
Objectives: The purpose of the present study was to evaluate the long-term effect of the microthr... more Objectives: The purpose of the present study was to evaluate the long-term effect of the microthread on the maintenance of marginal bone level.Material and methods: Seventeen patients were selected and two types of Astra Tech implants were installed, with the Microthread™ on the coronal portion of the fixture [Astra Tech Single Tooth Implant (ST)] or without the Microthread™ [Astra Tech TiOblast Implant (TB)]. ST and TB were installed adjacent to each other within the same partially edentulous sites and marginal bone loss was evaluated by radiographic image. The marginal bone-level alteration of the each fixture after prosthesis insertion was analyzed.Results: The marginal bone loss of ST and TB differed significantly during the observation period (P<0.01). Marginal bone levels of both ST and TB were stabilized after 1 year of lading.Conclusions: The Microthread™ might have an effect in maintaining the marginal bone loss against loading.
Background: The purpose of the present study was to investigate the short-term effects of microth... more Background: The purpose of the present study was to investigate the short-term effects of microthread location on peri-implant marginal bone levels.
The purpose of the present study was to investigate whether bone level on the tooth side was the ... more The purpose of the present study was to investigate whether bone level on the tooth side was the single dominant factor on the dimension of an interproximal papilla around single-tooth restorations made on a microthread, conical seal, and platform-switched design implant. Periapical radiographs were taken of 17 patients, each of whom was treated with a single implant. The bone levels on the tooth (Dt) and implant (Di) sides were recorded. The dimension of the papilla (Ph) was measured as the shortest distance from the top of the papilla to the crestal bone. The marginal bone levels of the implants were also measured. The Pearson correlation coefficient was used to correlate the variables, and a regression analysis was used to determine whether Di or Dt had a significant (P &amp;amp;amp;amp;lt;0.05) influence on Ph. A positive correlation existed between Ph and Di (r = 0.413; P = 0.023) and between Ph and Dt (r = 0.830; P &amp;amp;amp;amp;lt;0.0001). However, only Dt had a significant influence on Ph. Dt is the dominant factor that influences the interproximal soft tissue dimension between a natural tooth and a single implant with a microthread, conical seal, and platform-switched design.
In order to verify the results of interdental papilla regeneration, various methods of measuring ... more In order to verify the results of interdental papilla regeneration, various methods of measuring the length of the papilla have been introduced. Invasive methods, such as bone probing under local anesthesia, might cause discomfort to the patients and possibly damage the delicate gingival unit. The purpose of the present study was to validate a method of measuring the length of the interdental papilla non-invasively, using radiopaque material and a periapical radiograph. This study involved 142 interproximal papillae in 40 patients with chronic periodontitis. The distance between the radiopaque material and most coronal portion of the crestal bone was measured (radiographic length of papilla, RL). Bone probing at the interdental papilla was performed after local anesthesia (bone probing length, BPL). After flap elevation, the actual length of the papilla was measured (actual length of papilla, AL). A correlation analysis was performed between AL-RL and AL-BPL using Pearson&amp;amp;amp;amp;amp;amp;amp;amp;#39;s correlation coefficients. The correlation between AL-RL and AL-BPL was 0.903 and 0.931, respectively, both of which showed significance at the 0.01 level. The results of this study suggest that the noninvasive method using a radiopaque material and periapical radiograph could be utilized to measure the length of the interdental papilla.
The purpose of this study was to compare the dimension of interproximal soft tissue between adjac... more The purpose of this study was to compare the dimension of interproximal soft tissue between adjacent implants in distinctive implant systems. This study involved 85 interproximal papillae between two adjacent implants in 50 patients who had implants placed adjacent to each other and who had prosthesis in place for longer than 1 year. The shortest distance between the radiopaque material on the tip of interimplant papilla and the most coronal portion of the interimplant crestal bone was measured (radiographic length of papilla [RL]). The horizontal distance (HD) between the two adjacent implants was measured at the fixture-abutment interface level. Considering the possible effect of interimplant crestal bone resorption on closely implanted sites, HDs were divided into two categories: HD &lt;3 and &gt;or=3 mm. The Mann-Whitney test was performed to find the difference in the dimension of interimplant papilla. In cases of HD &lt;3 mm, RL did not differ statistically in both systems. Also, in cases of HD &gt;3 mm, RL did not show a statistically significant difference in both systems. Both systems had similar dimensions of interproximal soft tissue between adjacent implants, irrespective of the horizontal distance of the fixture.
Background: The interproximal papilla between two adjacent implants is gaining critical interest ... more Background: The interproximal papilla between two adjacent implants is gaining critical interest in the implant dentistry. The aims of this study were to evaluate the effect of 1) the width of keratinized mucosa, 2) the distance from the base of the contact point to the crestal bone, and 3) the horizontal distance between two implants on the radiographic dimension from the tip of the papilla to the crestal bone between two implants.
Abstract This study evaluates periodontal repair and biomaterial reaction following implantation ... more Abstract This study evaluates periodontal repair and biomaterial reaction following implantation of a polyglactin mesh with or without porous resorbable calcium carbonate (RCC) or porous replamineform hydroxyapatite (RHA) in conjunction with reconstructive surgery. Ligature- and surgically-induced interproximal periodontal defects of left and right mandibular premolar teeth in 7 dogs were used. Bilaterally, mesial defects of the 2nd, 3rd and 4th premolar teeth were treated with polyglactin mesh, polyglactin mesh and RHA. or polyglactin mesh and RCC. respectively. The polyglactin mesh, shaped according to the contour of the defect, was adapted to the experimental teeth: its coronal margin positioned immediately apical to the cemento-enamel junction. Gingival flap margins were adapted and sutured to cover the polyglactin mesh completely. Clinical healing was generally uneventful. The dogs were sacrificed to provide block sections for histologic evaluation at 1, 3, 6, 12, 26, 32 and 56 weeks following wound closure. Generally, cementum regeneration was observed beginning at week 6 in all groups. Bone regeneration was observed from week 3 in polyglactin mesh-treated groups, and from week 6 in polyglactin mesh + RCC or polyglactin mesh + RHA treated groups. Bone regeneration appeared enhanced in polyglactin mesh + RCC or polyglactin mesh + RHA treated defects at week 12 and 26, with little difference between the three experimental conditions at week 56. Polyglactin mesh degradation was observed at week 3 and appeared complete at week 12. The RHA did not appear to resorb, while the RCC was gradually replaced by bone from week 3. Within limitations of the study conditions, periodontal regeneration was observed following implantation of a polyglactin mesh with or without RCC or RHA in conjunction with reconstructive surgery. As a conclusion, there seems to be no significant difference in periodontal regeneration after 12 months of healing between the group treated with the membrane only, and the group treated with the membrane and the bone substitution material. Changes in connective fiber orientation over the 1st 12 weeks of healing may suggest that “fibrous encapsulation” observed in earlier studies may only represent a transient stage in periodontal regeneration.
To evaluate the periodontal tissue regenerative effects of a chitosan/collagen sponge applied to ... more To evaluate the periodontal tissue regenerative effects of a chitosan/collagen sponge applied to preclinical one-wall intrabony defects surgically created in beagle dogs. 4 x 4 mm one-wall intrabony defects were surgically created in the bilateral maxillary first and third, and the mandibular second and fourth premolars. The surgical control group received a flap operation only, while the buffer control group was treated afterwards with a phosphate-buffered saline/collagen sponge (CS) and the chitosan group was treated with a chitosan/cs. The subjects were killed 8 weeks after the operation, and a comparative histological examination was performed. The amount of junctional epithelium migration was 2.30+/-1.24 mm in the surgical control group, 1.49+/-1.25 mm in the buffer control group, and 0.26+/-0.59 mm in the chitosan group. A significant difference was exhibited only between the surgical control and the chitosan group (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The amount of connective tissue adhesion was 0.68+/-0.60, 1.07+/-0.91, and 0.41+/-0.42 mm in the surgical control, buffer control, and the chitosan group, respectively. The amount of cementum regeneration was 1.42+/-0.49, 1.60+/-0.41, and 3.46+/-0.78 mm in the surgical control, buffer control, and the chitosan group, respectively. A significant difference was seen between the chitosan group and the rest (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.01). The amount of alveolar bone regeneration was 1.00+/-0.77, 1.52+/-0.37, and 2.43+/-0.44 mm in the surgical control, buffer control, and the chitosan group, respectively. A significant difference was observed between the chitosan group and the rest (p&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The results demonstrate the beneficial effect of the chitosan/cs on the one-wall intrabony defects of beagle dogs. The inhibited apical migration of epithelium and the increase in the amount of new bone and new cementum suggest the potency of chitosan in inducing periodontal tissue regeneration.
The various methods for regeneration of periodontal tissue that have been developed can be classi... more The various methods for regeneration of periodontal tissue that have been developed can be classified into guided tissue regeneration and bone implantation. Since the implantation materials have shown both deficiencies and merits, dentists have begun exploring the bioactive glass first used in plastic surgery. This paper examines the effectiveness of this new material on periodontal intrabony defects.
Background: Recent interest in naturally based products has increased. Various herbal extracts ar... more Background: Recent interest in naturally based products has increased. Various herbal extracts are known to have a variety of medicinal properties. Among the various natural medicines, safflower seeds have beneficial effects on various bone diseases such as bone fracture, osteoporosis, and osteodysplasia. In addition, they are known to have anti-inflammatory effects. The objective of this study was to evaluate the effect of a safflower seed extract (SSE) on the regeneration of periodontal tissue in a preclinical 1-wall model in dogs.
The objective of this study was to histologically evaluate periodontal healing following flap sur... more The objective of this study was to histologically evaluate periodontal healing following flap surgery in intrabony periodontal defects to determine the influence of the number of bone walls on periodontal regeneration. One-, 2-, and 3-wall intrabony periodontal defects were surgically produced at the proximal aspect of mandibular premolars in either right or left jaw quadrants in six beagle dogs. Mucoperiosteal flaps were positioned and sutured to their presurgery position following defect preparation. The animals were euthanized at 8 weeks post-surgery, and block sections of the defect sites were collected for histologic and histometric analysis. Bone and cementum regeneration was positively correlated to the number of bone walls limiting the intrabony periodontal defects. The junctional epithelium averaged (+/- SD) 1.5 +/- 0.2, 1.2 +/- 0.3, and 0.9 +/- 0.2 mm for the 1-, 2-, and 3-wall defects, respectively, with the 3-wall defects being significantly different from the 1-wall defects (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Cementum regeneration averaged 1.2 +/- 0.6, 2.0 +/- 0.6, and 2.8 +/- 0.5 mm for the 1-, 2-, and 3-wall defects, respectively; all groups were significantly different from each other (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). Bone regeneration averaged 1.5 +/- 0.5, 1.7 +/- 0.6, and 2.3 +/- 0.5 mm for the 1-, 2-, and 3-wall defects, respectively, with the 3-wall defects being significantly different from the 1-wall defects (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;0.05). The results suggest that the number of bone walls is a critical factor determining treatment outcomes in intrabony periodontal defects. One- and 3-wall intrabony defects appear to be reproducible models to evaluate candidate technologies for periodontal regeneration.
Single-stranded genomic DNA of recombinant M13 phages was tested as an antisense molecule and exa... more Single-stranded genomic DNA of recombinant M13 phages was tested as an antisense molecule and examined for its usefulness in high-throughput functional genomics. cDNA fragments of various genes (TNF-a, c-myc, c-myb, cdk2 and cdk4) were independently cloned into phagemid vectors. Using the life cycle of M13 bacteriophages, large circular (LC)-molecules, antisense to their respective genes, were prepared from the culture supernatant of bacterial transformants. LC-antisense molecules exhibited enhanced stability, target specificity and no need for target-site searches. High-throughput functional genomics was then attempted with an LC-antisense library, which was generated by using a phagemid vector that incorporated a unidirectional subtracted cDNA library derived from liver cancer tissue. We identified 56 genes involved in the growth of these cells. These results indicate that an antisense sequence as a part of single-stranded LC-genomic DNA of recombinant M13 phages exhibits effective antisense activity, and may have potential for high-throughput functional genomics.
Ribbon antisense (RiAS) to the hTR RNA, a component of the telomerase complex, was employed to in... more Ribbon antisense (RiAS) to the hTR RNA, a component of the telomerase complex, was employed to inhibit telomerase activity and cancer cell growth. The antisense molecule, hTR-RiAS, combined with enhanced cellular uptake was shown to effectively inhibit telomerase activity and cause rapid cell death in various cancer cell lines. When cancer cells were treated with hTR-RiAS, the level of hTR RNA was reduced by more than 90% accompanied with reduction in telomerase activity. When checked for cancer cell viability, cancer cell lines treated with hTR-RiAS using DNA+Peptide+Lipid complex showed 70-80% growth inhibition in 3 days. The reduced cell viability was due to apoptosis as the percentage of cells exhibiting the sub-G0 arrest and DNA fragmentation increased after antisense treatment. Further, when subcutaneous tumors of a colon cancer cell line (SW480) were treated intratumorally with hTR-RiAS, tumor growth was markedly suppressed with almost total ablation of hTR RNA in the tumor tissue. Cells in the tumor tissue were also found to undergo apoptosis after hTR-RiAS treatment. These results suggest that hTR-RiAS is an effective anticancer reagent, with a potential for broad efficacy to diverse malignant tumors.
The new cholesterol-based cationic lipids B, C, and D with an ether linked spacer were synthesize... more The new cholesterol-based cationic lipids B, C, and D with an ether linked spacer were synthesized by using aminopropyl chain extension with acrylonitrile. The cholesterol-based cationic lipid A with carbamoyl linkage were also synthesized in order to compare the difference in transfection efficiency of the two linkage types. To this end, GFP expression of these cationic lipids was confirmed respectively.
Systematic secondary structure simulation of a target mRNA sequence is shown to be effective for ... more Systematic secondary structure simulation of a target mRNA sequence is shown to be effective for locating a good anti-sense target site. Multiple selected anti-sense sequences were placed in a single molecule. The anti-sense oligonucleotide (oligo) was covalently closed to avoid exonuclease activities and was designated CMAS (covalently closed multiple anti-sense)-oligo. CMAS-oligo was found to be stable, largely preserving its structural integrity after 24 h of incubation in the presence of either exonuclease III or serum. When human c-myb mRNA was targeted by the c-myb CMAS-oligo, expression of the gene was completely abolished. Further, tumour cell growth was inhibited by 82+/-3% as determined by an MTT [3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] assay and by 90+/-1% by [(3)H]thymidine incorporation. When a leukaemic cell line K562 was treated with CMAS-oligo, colony formation on soft agarose was also decreased by 93%. In contrast, treatment with a scrambled control oligo did not significantly inhibit leukaemic cell growth. These results suggest that a rational target site search is possible for an anti-sense oligo and that CMAS-oligo can be employed as an effective anti-sense agent with enhanced stability.
Objectives: The purpose of the present study was to evaluate the long-term effect of the microthr... more Objectives: The purpose of the present study was to evaluate the long-term effect of the microthread on the maintenance of marginal bone level.Material and methods: Seventeen patients were selected and two types of Astra Tech implants were installed, with the Microthread™ on the coronal portion of the fixture [Astra Tech Single Tooth Implant (ST)] or without the Microthread™ [Astra Tech TiOblast Implant (TB)]. ST and TB were installed adjacent to each other within the same partially edentulous sites and marginal bone loss was evaluated by radiographic image. The marginal bone-level alteration of the each fixture after prosthesis insertion was analyzed.Results: The marginal bone loss of ST and TB differed significantly during the observation period (P<0.01). Marginal bone levels of both ST and TB were stabilized after 1 year of lading.Conclusions: The Microthread™ might have an effect in maintaining the marginal bone loss against loading.
Background: The purpose of the present study was to investigate the short-term effects of microth... more Background: The purpose of the present study was to investigate the short-term effects of microthread location on peri-implant marginal bone levels.
The purpose of the present study was to investigate whether bone level on the tooth side was the ... more The purpose of the present study was to investigate whether bone level on the tooth side was the single dominant factor on the dimension of an interproximal papilla around single-tooth restorations made on a microthread, conical seal, and platform-switched design implant. Periapical radiographs were taken of 17 patients, each of whom was treated with a single implant. The bone levels on the tooth (Dt) and implant (Di) sides were recorded. The dimension of the papilla (Ph) was measured as the shortest distance from the top of the papilla to the crestal bone. The marginal bone levels of the implants were also measured. The Pearson correlation coefficient was used to correlate the variables, and a regression analysis was used to determine whether Di or Dt had a significant (P &amp;amp;amp;amp;lt;0.05) influence on Ph. A positive correlation existed between Ph and Di (r = 0.413; P = 0.023) and between Ph and Dt (r = 0.830; P &amp;amp;amp;amp;lt;0.0001). However, only Dt had a significant influence on Ph. Dt is the dominant factor that influences the interproximal soft tissue dimension between a natural tooth and a single implant with a microthread, conical seal, and platform-switched design.
In order to verify the results of interdental papilla regeneration, various methods of measuring ... more In order to verify the results of interdental papilla regeneration, various methods of measuring the length of the papilla have been introduced. Invasive methods, such as bone probing under local anesthesia, might cause discomfort to the patients and possibly damage the delicate gingival unit. The purpose of the present study was to validate a method of measuring the length of the interdental papilla non-invasively, using radiopaque material and a periapical radiograph. This study involved 142 interproximal papillae in 40 patients with chronic periodontitis. The distance between the radiopaque material and most coronal portion of the crestal bone was measured (radiographic length of papilla, RL). Bone probing at the interdental papilla was performed after local anesthesia (bone probing length, BPL). After flap elevation, the actual length of the papilla was measured (actual length of papilla, AL). A correlation analysis was performed between AL-RL and AL-BPL using Pearson&amp;amp;amp;amp;amp;amp;amp;amp;#39;s correlation coefficients. The correlation between AL-RL and AL-BPL was 0.903 and 0.931, respectively, both of which showed significance at the 0.01 level. The results of this study suggest that the noninvasive method using a radiopaque material and periapical radiograph could be utilized to measure the length of the interdental papilla.
The purpose of this study was to compare the dimension of interproximal soft tissue between adjac... more The purpose of this study was to compare the dimension of interproximal soft tissue between adjacent implants in distinctive implant systems. This study involved 85 interproximal papillae between two adjacent implants in 50 patients who had implants placed adjacent to each other and who had prosthesis in place for longer than 1 year. The shortest distance between the radiopaque material on the tip of interimplant papilla and the most coronal portion of the interimplant crestal bone was measured (radiographic length of papilla [RL]). The horizontal distance (HD) between the two adjacent implants was measured at the fixture-abutment interface level. Considering the possible effect of interimplant crestal bone resorption on closely implanted sites, HDs were divided into two categories: HD &lt;3 and &gt;or=3 mm. The Mann-Whitney test was performed to find the difference in the dimension of interimplant papilla. In cases of HD &lt;3 mm, RL did not differ statistically in both systems. Also, in cases of HD &gt;3 mm, RL did not show a statistically significant difference in both systems. Both systems had similar dimensions of interproximal soft tissue between adjacent implants, irrespective of the horizontal distance of the fixture.
Background: The interproximal papilla between two adjacent implants is gaining critical interest ... more Background: The interproximal papilla between two adjacent implants is gaining critical interest in the implant dentistry. The aims of this study were to evaluate the effect of 1) the width of keratinized mucosa, 2) the distance from the base of the contact point to the crestal bone, and 3) the horizontal distance between two implants on the radiographic dimension from the tip of the papilla to the crestal bone between two implants.
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