Initial adhesion of bone marrow stromal cells to various bone graft substitutes

PURPOSE: The aim of this study is to determine whether certain biomaterials have the potential to support cell attachment. After seeding bone marrow stromal cells onto the biomaterials, we investigated their responses to each material in vitro. METHODS: Rat bone marrow derived stromal cells were used. The biomaterials were deproteinized bovine bone mineral (DBBM), DBBM coated with fibronectin (FN), synthetic hydroxyapatite (HA), HA coated with FN, HA coated with beta-tricalcium phosphate (TCP), and pure beta-TCP. With confocal laser scanning microscopy, actin filaments and vinculin were observed after 6, 12, and 24 hours of cell seeding. The morphological features of cells on each biomaterial were observed using scanning electron microscopy at day 1 and 7. RESULTS: The cells on HA/FN and HA spread widely and showed better defined actin cytoskeletons than those on the other biomaterials. At the initial phase, FN seemed to have a favorable effect on cell adhesion. In DBBM, very few cells adhered to the surface. CONCLUSIONS: Within the limitations of this study, we can conclude that in contrast with DBBM not supporting cell attachment, HA provided a more favorable environment with respect to cell attachment.

The evaluation of the correlation between histomorphometric analysis and micro-computed tomography analysis in AdBMP-2 induced bone regeneration in rat calvarial defects

PURPOSE: Micro-computed tomography (micro-CT) has been widely used in the evaluation of regenerated bone tissue but the reliability of micro-CT has not yet been established. This study evaluated the correlation between histomorphometric analysis and micro-CT analysis in performing new bone formation measurement. METHODS: Critical-size calvarial defects were created using a 8 mm trephine bur in a total of 24 Sprague-Dawley rats, and collagen gel mixed with autogenous rat bone marrow stromal cells (BMSCs) or autogenous rat BMSCs transduced by adenovirus containing bone morphogenic protein-2 (BMP-2) genes was loaded into the defect site. In the control group, collagen gel alone was loaded into the defect. After 2 and 4 weeks, the animals were euthanized and calvaria containing defects were harvested. Micro-CT analysis and histomorphometric analysis of each sample were accomplished and the statistical evaluation about the correlation between both analyses was performed. RESULTS: New bone formation of the BMP-2 group was greater than that of the other groups at 2 and 4 weeks in both histomorphometric analysis and micro-CT analysis (P=0.026, P=0.034). Histomorphometric analysis of representative sections showed similar results to histomorphometric analysis with a mean value of 3 sections. Measurement of new bone formation was highly correlated between histomorphometric analysis and micro-CT analysis, especially at the low lower threshold level at 2 weeks (adjusted r2=0.907, P<0.001). New bone formation of the BMP-2 group analyzed by micro-CT tended to decline sharply with an increasing lower threshold level, and it was statistically significant (P<0.001). CONCLUSIONS: Both histomorphometric analysis and micro-CT analysis were valid methods for measurement of the new bone in rat calvarial defects and the ability to detect the new bone in micro-CT analysis was highly influenced by the threshold level in the BMP-2 group at early stage.

Biological effects of a semiconductor diode laser on human periodontal ligament fibroblasts

PURPOSE: It has been reported that low-level semiconductor diode lasers could enhance the wound healing process. The periodontal ligament is crucial for maintaining the tooth and surrounding tissues in periodontal wound healing. While low-level semiconductor diode lasers have been used in low-level laser therapy, there have been few reports on their effects on periodontal ligament fibroblasts (PDLFs). We performed this study to investigate the biological effects of semiconductor diode lasers on human PDLFs. METHODS: Human PDLFs were cultured and irradiated with a gallium-aluminum-arsenate (GaAlAs) semiconductor diode laser of which the wavelength was 810 nm. The power output was fixed at 500 mW in the continuous wave mode with various energy fluencies, which were 1.97, 3.94, and 5.91 J/cm2. A culture of PDLFs without laser irradiation was regarded as a control. Then, cells were additionally incubated in 72 hours for MTS assay and an alkaline phosphatase (ALPase) activity test. At 48 hours post-laser irradiation, western blot analysis was performed to determine extracellular signal-regulated kinase (ERK) activity. ANOVA was used to assess the significance level of the differences among groups (P<0.05). RESULTS: At all energy fluencies of laser irradiation, PDLFs proliferation gradually increased for 72 hours without any significant differences compared with the control over the entire period taken together. However, an increment of cell proliferation significantly greater than in the control occurred between 24 and 48 hours at laser irradiation settings of 1.97 and 3.94 J/cm2 (P<0.05). The highest ALPase activity was found at 48 and 72 hours post-laser irradiation with 3.94 J/cm2 energy fluency (P<0.05). The phosphorylated ERK level was more prominent at 3.94 J/cm2 energy fluency than in the control. CONCLUSIONS: The present study demonstrated that the GaAlAs semiconductor diode laser promoted proliferation and differentiation of human PDLFs.

Bone regeneration effects of human allogenous bone substitutes: a preliminary study

PURPOSE: The purpose of this study was to compare the bone regeneration effects of cortical, cancellous, and cortico-cancellous human bone substitutes on calvarial defects of rabbits. METHODS: Four 8-mm diameter calvarial defects were created in each of nine New Zealand white rabbits. Freeze-dried cortical bone, freeze-dried cortico-cancellous bone, and demineralized bone matrix with freeze-dried cancellous bone were inserted into the defects, while the non-grafted defect was regarded as the control. After 4, 8, and 12 weeks of healing, the experimental animals were euthanized for specimen preparation. Micro-computed tomography (micro-CT) was performed to calculate the percent bone volume. After histological evaluation, histomorphometric analysis was performed to quantify new bone formation. RESULTS: In micro-CT evaluation, freeze-dried cortico-cancellous human bone showed the highest percent bone volume value among the experimental groups at week 4. At week 8 and week 12, freeze-dried cortical human bone showed the highest percent bone volume value among the experimental groups. In histologic evaluation, at week 4, freeze-dried cortico-cancellous human bone showed more prominent osteoid tissue than any other group. New bone formation was increased in all of the experimental groups at week 8 and 12. Histomorphometric data showed that freeze-dried cortico-cancellous human bone showed a significantly higher new bone formation percentile value than any other experimental group at week 4. At week 8, freeze-dried cortical human bone showed the highest value, of which a significant difference existed between freeze-dried cortical human bone and demineralized bone matrix with freeze-dried cancellous human bone. At week 12, there were no significant differences among the experimental groups. CONCLUSIONS: Freeze-dried cortico-cancellous human bone showed swift new bone formation at the 4-week healing phase, whereas there was less difference in new bone formation among the experimental groups in the following healing phases.

Effects of fibrin-binding oligopeptide on osteopromotion in rabbit calvarial defects

PURPOSE: Fibronectin (FN) has been shown to stimulate bone regeneration in animal models. The aim of this study was to evaluate the capacity of bovine bone mineral coated with synthetic oligopeptides to enhance bone regeneration in rabbit calvarial defects. METHODS: Oligopeptides including fibrin-binding sequences of FN repeats were synthesized on the basis of primary and tertiary human plasma FN structures. Peptide coated and uncoated bone minerals were implanted into 10 mm calvarial defects in New Zealand white rabbits, and the animals were sacrificed at 4 or 8 weeks after surgery. After specimens were prepared, histologic examination and histomorphometric analysis were performed. RESULTS: At 4 weeks after surgery, the uncoated groups showed a limited amount of osteoid formation at the periphery of the defect and the oligopeptide coated groups showed more osteoid formation and new bone formation in the center of the defect as well as at the periphery. At 8 weeks, both sites showed increased new bone formation. However, the difference between the two sites had reduced. CONCLUSIONS: Fibrin-binding synthetic oligopeptide derived from FN on deproteinized bovine bone enhanced new bone formation in rabbit calvarial defects at the early healing stage. This result suggests that these oligopeptides can be beneficial in reconstructing oral and maxillofacial deformities or in regenerating osseous bone defects.

Periodontal regeneration capacity of equine particulate bone in canine alveolar bone defects

PURPOSE: This study was performed to evaluate the periodontal wound healing effect of particulate equine bone mineral on canine alveolar bone defects. METHODS: Twelve adult male beagle dogs were used as study subjects. The mandibular second and fourth premolars were extracted prior to the experimental surgery, and the extraction sites were allowed to heal for 8 weeks. After periodontal probing, two-walled defects were created at the mesial and distal sides of the mandibular third premolars bilaterally, and the defects were filled with equine particulate bone with collagen membrane or bovine particulate bone with collagen membrane, or collagen membrane alone. The defects without any treatment served as negative controls. After probing depth measurement, animals were sacrificed at 10, 16, and 24 post-surgery weeks for micro-computed tomographic and histomorphometric analysis. RESULTS: The equine particulate bone-inserted group showed significantly decreased values of probing depth and first bone contact compared to the negative control and collagen membrane alone groups at weeks 10, 16, and 24 (P < 0.05). There were no significant differences in the new cementum length, newly-formed bone area, or newly-formed bone volume between equine particulate bone- and bovine particulate bone-inserted groups, both of which showed significantly increased values compared to the negative control and collagen membrane alone groups (P < 0.05). CONCLUSIONS: Equine particulate bone showed significant differences in probing depth, first bone contact, new cementum length, newly formed bone area, and bone volume fraction values when compared to the negative control and collagen membrane alone groups. There were no significant differences between equine and bovine particulate bone substitutes in these parameters; therefore, we can conclude that equine particulate bone is equivalent to bovine bone for periodontal regeneration.

Socket preservation using deproteinized horse-derived bone mineral

PURPOSE: The healing process following tooth extraction apparently results in a pronounced resorption of the alveolar ridge. As a result, the width of alveolar ridge is reduced and severe alveolar bone resorption occurs. The purpose of this experiment is to clinically and histologically evaluate the results of using horse-derived bone mineral for socket preservation. METHODS: The study comprised 4 patients who were scheduled for extraction as a consequence of severe chronic periodontitis or apical lesion. The extraction was followed by socket preservation using horse-derived bone minerals. Clinical parameters included buccal-palatal width, mid-buccal crest height, and mid-palatal crest height. A histologic examination was conducted. RESULTS: The surgical sites healed uneventfully. The mean ridge width was 7.75 +/- 2.75 mm at baseline and 7.00 +/- 2.45 mm at 6 months. The ridge width exhibited no significant difference between baseline and 6 months. The mean buccal crest height at baseline was 7.5 +/- 5.20 mm, and at 6 months, 3.50 +/- 0.58 mm. The mean palatal crest height at baseline was 7.75 +/- 3.10 mm, and at 6 months, 5.00 +/- 0.82 mm. There were no significant differences between baseline and 6 months regarding buccal and palatal crest heights. The amount of newly formed bone was 9.88 +/- 2.90%, the amount of graft particles was 42.62 +/- 6.57%, and the amount of soft tissue was 47.50 +/- 9.28%. CONCLUSIONS: Socket preservation using horse-derived bone mineral can effectively maintain ridge dimensions following tooth extraction and can promote new bone formation through osteoconductive activities.

Biological effects of a porcine-derived collagen membrane on intrabony defects

PURPOSE: To prolong the degradation time of collagen membranes, various cross-linking techniques have been developed. For cross-linking, chemicals such as formaldehyde and glutaraldehyde are added to collagen membranes, but these chemicals could adversely affect surrounding tissues. The aim of this study is to evaluate the ability of porous non-chemical cross-linking porcine-derived collagen nanofibrous membrane to enhance bone and associated tissue regeneration in one-wall intrabony defects in beagle dogs. METHODS: The second and third mandibular premolars and the first molars of 2 adult beagles were extracted bilaterally and the extraction sites were allowed to heal for 10 weeks. One-wall intrabony defects were prepared bilaterally on the mesial and distal side of the fourth mandibular premolars. Among eight defects, four defects were not covered with membrane as controls and the other four defects were covered with membrane as the experimental group. The animals were sacrificed 10 weeks after surgery. RESULTS: Wound healing was generally uneventful. For all parameters evaluating bone regeneration, the experimental group showed significantly superior results compared to the control. In new bone height (NBh), the experimental group exhibited a greater mean value than the control (3.04 +/- 0.23 mm/1.57 +/- 0.59, P = 0.003). Also, in new bone area (NBa) and new bone volume (NBv), the experimental group showed superior results compared to the control (NBa, 34.48 +/- 10.21% vs. 5.09 +/- 5.76%, P = 0.014; and NBv, 28.04 +/- 12.96 vs. 1.55 +/- 0.57, P = 0.041). On the other hand, for parameters evaluating periodontal tissue regeneration, including junctional epithelium migration and new cementum height, there were no statistically significant differences between two groups. CONCLUSIONS: Within the limitations of this study, this collagen membrane enhanced bone regeneration at one-wall intrabony defects. On the other hand, no influence of this membrane on periodontal tissue regeneration could be ascertained in this study.

Biological effects of a root conditioning agent for dentin surface modification in vitro

PURPOSE: Connective tissue reattachment to periodontally damaged root surfaces is one of the most important goals of periodontal therapy. The aim of this study was to develop a root conditioning agent that can demineralize and detoxify the infected root surface. METHODS: Dentin slices obtained from human teeth were treated with a novel root planing agent for 2 minutes and then washed with phosphate-buffered saline. Smear layer removal and type I collagen exposure were observed by scanning electron microscopy (SEM) and type I collagen immunostaining, respectively. Cell attachment and lipopolysaccharides (LPS) removal demonstrated the efficiency of the root conditioning agent. RESULTS: SEM revealed that the smear layer was entirely removed and the dentinal tubules were opened by the experimental gel. Type I collagen was exposed on the surfaces of the dentin slices treated by the experimental gel, which were compared with dentin treated with other root planing agents. Dentin slices treated with the experimental gel showed the highest number of attached fibroblasts and flattened cell morphology. The agar diffusion assay demonstrated that the experimental gel also has effective antimicrobial activity. Escherichia coli LPS were effectively removed from well plates by the experimental gel. CONCLUSIONS: These results demonstrated that this experimental gel is a useful tool for root conditioning of infected root surfaces and can also be applied for detoxification of ailing implant surface threads.

Immunomodulatory effect of canine periodontal ligament stem cells on allogenic and xenogenic peripheral blood mononuclear cells

PURPOSE: The aim of this study was to investigate the immunomodulatory effects of canine periodontal ligament stem cells on allogenic and xenogenic immune cells in vitro. METHODS: Mixed cell cultures consisting of canine stem cells (periodontal ligament stem cells and bone marrow stem cells) and allogenic canine/xenogenic human peripheral blood mononuclear cells (PBMCs) were established following the addition of phytohemagglutinin. The proliferation of PBMCs was evaluated using the MTS assay. The cell division of PBMCs was analyzed using the CFSE assay. The apoptosis of PBMCs was assessed using the trypan blue uptake method. RESULTS: Periodontal ligament stem cells and bone marrow stem cells inhibited the proliferation of allogenic and xenogenic PBMCs. Both periodontal ligament stem cells and bone marrow stem cells suppressed the cell division of PBMCs despite the existence of a mitogen. No significant differences in the percentages of apoptotic PBMCs were found among the groups. CONCLUSIONS: Canine periodontal ligament stem cells have an immunomodulatory effect on allogenic and xenogenic PBMCs. This effect is not a product of apoptosis of PBMCs but is caused by the inhibition of cell division of PBMCs.

Investigation of postnatal stem cells from canine dental tissue and bone marrow / 대한치주과학회지

PURPOSE: The aim of this study was to evaluate the stemness of cells from canine dental tissues and bone marrow. METHODS:Canine periodontal ligament stem cells (PDLSC), alveolar bone stem cells (ABSC) and bone marrow stem cells(BMSC) were isolated and cultured. Cell differentiations (osteogenic, adipogenic and chondrogenic) and surface antigens (CD146, STRO-1, CD44, CD90, CD45, CD34) were evaluated in vitro. The cells were transplanted into the subcutaneous space of nude mice to assess capacity for ectopic bone formation at 8 weeks after implantation. RESULTS: PDLSC, ABSC and BMSC differentiated into osteoblasts, adipocytes and chondrocytes under defined condition. The cells expressed the mesenchymal stem cell markers differently. When transplanted into athymic nude mice, these three kinds of cells with hydroxyapatite /beta tricalcium phosphate (HA/TCP) carrier showed ectopic bone formation. CONCLUSIONS: This study demonstrated that canine dental stem cells have stemness like bone marrow stem cells. Transplantation of these cells might be used as a therapeutic approach for dental stem cell-mediated periodontal tissue regeneration.

Clinical study of guided bone regeneration of extracted socket with PLA/PGA membrane and silk fibroin membrane / 대한치주과학회지

PURPOSE: This study was designed to compare the bond regeneratiom effects of treatment using silk fibroin membrane ( Nanogide-S (R)) resorbable barrier with control group treated by polyactic acid / polylacticglycolic acid membrane(Biomesh (R) ) METHODS:44 severe bone loss on extraction socket from 44 patients were used in this study. In experimental group 22 sites of them were treated by silk fibrin membrane as and the other 22 sites were treated by polyactic acid/ polylacticglycolic acid membrane as a control group. Clinical parameters including recovered bone width, length and radiographic parameter of vertical length were evlauated at base line and 3 months after surgery. RESULTS: 1) Severe bone width, length was significantlly decreased in two group. 2) Bone width, length was significantlly decreased in two group. 3) Decreased bone width, length and radiographic examination differences between group. CONCLUSIONS: On the basis of these results, silk fibrin resorbable membrane has similar bone regeneration ability to polyactic acid / polylacticglycolic acid membrane in guided bone regeneration for severe bone loss defect on extraction socket.

The biologic effect of fibrin-binding synthetic oligopeptide on periodontal ligament cells / 대한치주과학회지

PURPOSE: Fibronectin(FN), one of the major components of ECM, mediates wide variety of cellular interactions including cell adhesion, migration, proliferation and differentiation. In this study, we used synthetic peptides based on fibrin binding sites of amino-terminal of FN and evaluated their biologic effects on periodontal ligament(PDL) cells. MATERIALS AND METHODS: PDL cells were cultured on synthetic oligopeptides coated dishes and examined for cell adhesion, proliferation via confocal microscope. For detection of ERK1/2, cells were plated and Western blot analysis was performed. RESULTS: PDL cells on synthetic oligopeptide coated dishes showed enhanced cell adhesion and proliferation. Western blot analysis revealed increased level of ERK1/2 phosphorylation in cells plated on FN fragment containing fibrin-binding domain(FF1 and FF5) coated dishes. CONCLUSION: These results reveals that FN fragment containing fibrin-binding domain possess an enhanced biologic effect of PDL ligament cells.

The influence of membrane exposure on post-extraction dimensional change following ridge preservation technique / 대한치주과학회지

PURPOSE: Following tooth extraction caused by severe periodontitis, alveolar ridge dimension lose their original volume. To reduce the alveolar ridge dimension, the ridge preservation technique has been introduced and tested in many clinical studies with membrane alone or membrane plus graft, achieving reduced ridge loss compared to extraction only. The aim of the present clinical study was to compare the post-extraction dimensional changes in the membrane exposure group to non-exposure group during healing period following ridge preservation technique. METHODS: Ridge preservation was performed in 44 extraction sites. After extraction, deproteinized bovine bone mineral coated with synthetic oligopeptide (Ossgen-X15(R)) or deproteinized bovine bone mineral (Bio-Oss(R)) was implanted into the socket. A collagen membrane (Bio-Gide(R)) was trimmed to cover the socket completely and applied to the entrance of the socket. Four clinical parameters were compared between baseline and 6 months. RESULTS: During healing period, membrane exposure was observed at 19 sites. At the re-entry, hard newly formed tissue were observed at the ridge preservation site. The grafted socket sites were well preserved in their volume dimension. In both groups, horizontal ridge width was reduced and vertical height was increased. There were not statistically significant differences in horizontal (-1.32 mm vs -1.00 mm) and vertical ridge change (2.24 mm vs 2.37 mm at buccal crest, 1.36 mm vs. 1.53 mm at lingual crest) between two groups. CONCLUSIONS: The ridge preservation approach after tooth extraction effectively prevented resorption of hard tissue ridge in spite of membrane exposure during healing period.

Effect of combinatorial bone morphogenetic protein 2 and bone morphogenetic protein 7 gene delivery on osteoblastic differentiation / 대한치주과학회지

PURPOSE: Gene therapy (ex vivo) has recently been used as a means of delivering bone morphogenetic proteins (BMPs) to sites of tissue regeneration. In the present study, we investigated the effect of co-transduction of adenoviruses expressing BMP-2 and BMP-7 on osteogenesisof C2C12 cells in vitro. METHODS: A replication-defective human adenovirus 5 (Ad5) containing a cDNA for BMPs in the E1 region of the virus (Ad5BMP-2 and Ad5BMP-7) was constructed by in vivo homologous recombination. Functional activity of Ad5BMP-2 and Ad5BMP-7 were evaluated in mouse stromal cells (W20-17cells). C2C12 cells are transduced with various MOI (multiplicity of infection) of Ad5BMP-2 and Ad5BMP-7 to assess most effective and stable titer. Based on this result, C2C12 cells were transduced with Ad5BMP-2 and Ad5BMP-7 alone or by combination. BMPs expression, alkaline phosphatase (ALPase) activity, cell proliferation, and mineralization were assessed. RESULTS: Ad5BMP-2 and Ad5BMP-7 are successfully transduced to W20-17 cells, and secreted BMPs stimulated cell differentiation. Also, C2C12 cells transduced with Ad5BMPs showed expression of BMPs and increased ALPaseactivity. In all groups, cell proliferation was observed over times. At 7days, cells co-transduced with Ad5BMP-2 and Ad5BMP-7 showed lower proliferation than the others. C2C12 cells co-transduced with Ad5BMP-2 and Ad5BMP-7 had greater ALPaseactivity than that would be predicted if effect of individual Ad5BMPs were additive. Little mineralized nodule formation was detected in cells transduced with individual Ad5BMPs. In contrast, Ad5BMP-2 and Ad5BMP-7 combination stimulated mineralization after culturing for 10 days in mineralizing medium. CONCLUSIONS: Present study demonstrated that adenoviruses expressing BMPs gene successfully produced BMPs protein and these BMPs stimulated cells to be differentiated into osteoblastic cells. In addition, the osteogenic activity of Ad5BMPs can be synergistically increased by co-transduction of cells with Ad5BMP-2 and Ad5BMP-7.

Clinical presentation of a horse-derived biomaterial and its Biocompatibility: A Clinical Case Report / 대한치주과학회지

PURPOSE: The objective of this clinical presentation was to present a clinical case series report of socket preservation, sinus augmentation, and bone grafting using a horse-derived biomaterial. METHODS: A horse-derived biomaterial was used in 8 patients for different indications including socket preservation following tooth extraction, osseous bone grafting, and sinus augementation procedures. Surgeries were performed by a well trained specialist and clinical radiographs were obtained at designated intervals. Biopsy cores of 2 x 8 mm prior to implant placement was obtained following a healing interval of 4 - 6 months. A clinical and histologic evaluation was performed to evaluate the clinical effectiveness and biocompatibility of the biomaterial. RESULTS: All surgeries in 8 patients were successful with uneventful healing except for one case with membrane exposure that eventually resulted with a positive outcome. Radiographic display of the healing phase during different intervals showed increased radiopacity of granular nature as the healing time increased. No signs of adverse effect or infection was observed clinically and the tissues surrounding the biomaterial seemed well-tolerated with good intentional healing. The augmented sinuses healed uneventfully suggesting in part, good biocompatibility of the biomaterial. Dental implants placed following socket preservation were inserted with high initial torque suggesting good initial stability and bone quality. CONCLUSIONS: Our results show that at least on a tentative level, a horse-derived biomaterial may be used clinically in socket preservation, sinus augmentation, bone grafting techniques with good intentional healing and positive results.

Survey study of powered toothbrush with guiding device for oral hygiene improvement / 대한치주과학회지

PURPOSE: This study was performed to evaluate the effect of powered toothbrush with a wireless remote display on the subjective and objective oral hygiene improvement. METHODS: One hundred and fifteen subjects in healthy or mild gingivitis status between the ages of 20 and 90 were recruited and reviewed for study inclusion criteria. At first visit, 115 pre-screened subjects filled in the questionnaire form which consisted of demographic factors, behavioral factors (smoking, alcohol consumption), toothbrushing habits (brushing time and frequency), self-reported oral health status, and self-satisfaction. Baseline clinical indices (Plaque index, Gingival index) were also recorded by a periodontist. Subjects were instructed how to use powered toothbrush with a wireless remote display, and were provided with it. Thirty days after first visit, 90 subjects returned for the second assessment by self-reported questionnaire form and professional clinical checkup. Statistical analysis was performed using paired t-test for the difference between baseline and second visit data. The relationship among variables was examined with chi-square test and Fisher's exact test. RESULTS: Significant differences were not found on self-reported satisfaction related with sex, smoking, alcohol consumption (P<0.05). Self-reported tooth brushing habit was improved in the aspect of brushing time and frequency. Significant differences were found on the self-reported oral health status, self-satisfaction, and clinical indices between the baseline and second visit data (P<0.01). Clinical indices were significantly reduced after using powered toothbrush with a wireless remote display (P<0.01). No adverse reactions were reported during the study period. CONCLUSIONS: Powered toothbrush with a wireless remote display successfully promoted oral hygiene from the subjective and objective viewpoint after 30 days of home usage.

Correction of anterior ridge defect for conventional prosthesis / 대한치주과학회지

PURPOSE: Anterior ridge defect after tooth extraction results in unfavorable appearance. Ridge augmentation procedures should be preceded by careful surgical-prosthetic treatment planning, and various techniques can be used in anterior ridge augmentation. MATERIALS AND METHODS: Three patients showed deformed ridges after tooth extraction. Three different techniques ; onlay-interpositional connective tissue graft; bovine hydroxyapatite graft with free connective tissue graft; bovine hydroxyapatite graft with resorbable collagen membrane following free connective tissue graft; were used for anterior ridge augmentation. RESULT: Soft tissue graft can be used in small amount of ridge defect, hard tissue graft combined with soft tissue graft can be used in large amount of ridge defect. After ridge augmentation, about three months of healing period, augmented tissue was stabilized. The final restoration was initiated after this healing period, and the tissue form was maintained stable. CONCLUSION: Careful diagnosis and surgical-prosthetic treatment planning with joint consultation prior to surgery should be performed in order to attain an optimal esthetic results.

Crown lengthening for altered passive eruption / 대한치주과학회지

PURPOSE: Passive eruption is characterized by the apical shift of the dentogingival junction. As this occurs, the length of the clinical crown increases as the epithelial attachment migrates apically. Altered passive eruption occurs when the margin of gingiva is malpositioned incisally on the anatomic crown in adulthood and results in excessive gingiva. The purpose of this article is to evaluate esthetic results of crown lengthening procedure in altered passive eruption.s. MATERIALS AND METHODS: Three patients who complained "My front teeth look too short" were included. Bone sounding with periodontal probe revealed that alveolar bone crest was close to CEJ. Based on the diagnostic information, a diagnosis of altered passive eruption was made. They were performed apically positioned flap procedure with osseous resection. RESULTS: Six months later, all patients achieved favorable esthetic results and gingival margins were healthy and stable. CONCLUSION: When the diagnostic procedures reveal alveolar bone crest levels approximating the CEJ, apically positioned flap procedure with osseous resection is indicated.

Experimental study on the periodontal regenerative capacity of moldable synthetic peptide domain gel in degree III furcation defect of beagles / 대한치주과학회지

PURPOSE: Osteopontin is one of the major non-collagenous protein of hard tissue. Use of peptide domain of biologically active protein has some advantages. The objective of this experimental study is evaluation of periodontal regenerative potency of synthetic peptide gel which containing collagen binding domain of osteopontin in the degree III periodontal defect of beagle dogs. MATERIAL AND METHODS: Experimental degree III furcation defect was made in the mandibular third and fourth premolar of beagles. Regenerative material was applied during flap operation. 8 weeks after regenerative surgery, all animals were sacrificed and histomorphometric measurement was performed to calculate the linear percentage of the new cementum formation and the volume percentage of new bone formation. RESULT: The linear percent of new cementum formation was 41.6% at control group and 67.1% at test group and there was statistically significant difference. The volume percent of new bone formation was 52.1% at control group and 58.9% at test group. CONCLUSION: As the results of present experiment, synthetic peptide gel containing collagen binding domain of osteopontin significantly increase new bone and cementum formation in the degree III furcation defect of canine mandible.