Impact of scanning strategy on the accuracy of complete-arch intraoral scans:a preliminary study on segmental scans and merge methods

PURPOSE@#. This study investigated the accuracy of full-arch intraoral scans obtained by various scan strategies with the segmental scan and merge methods. @*MATERIALS AND METHODS@#. Seventy intraoral scans (seven scans per group) were performed using 10 scan strategies that differed in the segmental scan (1, 2, or 3 segments) and the scanning motion (straight, zigzag, or combined). The three-dimensional (3D) geometric accuracy of scan images was evaluated by comparison with a reference image in an image analysis software program, in terms of the arch shape discrepancies. Measurement parameters were the intermolar distance, interpremolar distance, anteroposterior distance, and global surface deviation. One-way analysis of variance and Tukey honestly significance difference post hoc tests were carried out to compare differences among the scan strategy groups (α = .05). @*RESULTS@#. The linear discrepancy values of intraoral scans were not different among scan strategies performed with the single scan and segmental scan methods. In general, differences in the scan motion did not show different accuracies, except for the intermolar distance measured under the scan conditions of a 3-segmental scan and zigzag motion. The global surface deviations were not different among all scan strategies. @*CONCLUSION@#. The segmental scan and merge methods using two scan parts appear to be reliable as an alternative to the single scan method for full-arch intraoral scans. When three segmental scans are involved, the accuracy of complete arch scan can be negatively affected.

Effect of repeated use of an implant handpiece on an output torque: An in-vitro study

Purpose@#This study aimed to evaluate the effect of repeated use of an implant handpiece under an implant placement torque (35 Ncm) and overloading torque condition (50 Ncm) on an output torque. @*Materials and Methods@#Two types of implant handpiece systems (Surgicpro/X-DSG20L [NSK, Kanuma, Japan] and SIP20/CRB46LN [SAESHIN, Daegu, South Korea]) were used. The output torque was measured using a digital torque gauge. The height and angle (x, y, and z axes) of the digital torque gauge and implant handpiece were adjusted through a jig for passive connection. The experiment was conducted under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150).For statistical analysis, the difference between the groups was analyzed using the Mann–Whitney U test and the Friedman test was used to confirm the change in output torque (α=.05). @*Results@#NSK and SAESHIN implant handpieces showed significant differences in output torque results at the setting torques of 35 Ncm and 50 Ncm (P <.001). The type of implant handpiece and repeated use influenced the output torque (P <.001). @*Conclusion@#. There may be a difference between the setting torque and actual output torque due to repeated use, and the implant handpiece should be managed and repaired during long-term use. In addition, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.

Effect of repeated use of an implant handpiece on an output torque: An in-vitro study

Purpose@#This study aimed to evaluate the effect of repeated use of an implant handpiece under an implant placement torque (35 Ncm) and overloading torque condition (50 Ncm) on an output torque. @*Materials and Methods@#Two types of implant handpiece systems (Surgicpro/X-DSG20L [NSK, Kanuma, Japan] and SIP20/CRB46LN [SAESHIN, Daegu, South Korea]) were used. The output torque was measured using a digital torque gauge. The height and angle (x, y, and z axes) of the digital torque gauge and implant handpiece were adjusted through a jig for passive connection. The experiment was conducted under the setting torque value of 35 Ncm (implant placement torque) and 50 Ncm (overloading torque condition) and 30 times per set; a total of 5 sets were performed (N = 150).For statistical analysis, the difference between the groups was analyzed using the Mann–Whitney U test and the Friedman test was used to confirm the change in output torque (α=.05). @*Results@#NSK and SAESHIN implant handpieces showed significant differences in output torque results at the setting torques of 35 Ncm and 50 Ncm (P <.001). The type of implant handpiece and repeated use influenced the output torque (P <.001). @*Conclusion@#. There may be a difference between the setting torque and actual output torque due to repeated use, and the implant handpiece should be managed and repaired during long-term use. In addition, for successful implant results in dental clinics, the output torque of the implant handpiece system should be checked before implant placement.

Comparison of Temperatures of the Resin Cement in Polycrystalline Ceramic Brackets Irradiated Using a Diode Laser

Purpose@#The primary objective of this study was to evaluate the change in the temperature of the adhesive resin in polycrystalline ceramic brackets irradiated using a diode laser at different irradiation energy levels and times. @*Materials and Methods@#For the measurement of the temperature of the adhesive resin, it was applied at the base of the ceramic bracket, a thermocouple was placed at the center of the base surface, the bracket was placed on prepared resin specimens for light curing, and a laser was irradiated to the center of the bracket slot at 5, 7, and 10 W. For the measurement of the temperatures of the enamel under the bracket and pulp cavity, extracted premolar was fixed to a prepared mold and the ceramic bracket was bonded to the buccal surface of the premolar. The Kruskal–Wallis H test and Friedman test were used for statistical analysis.Result: At 5 W, the temperature of the adhesive resin did not reach the resin softening temperature of 200°C within 30 seconds. At 7 W, it reached 200°C when the ceramic bracket was irradiated continuously for 28 seconds. At 10 W, it reached 200°C when the ceramic bracket was irradiated continuously for 15 seconds. During laser irradiation, the temperature of the enamel under the bracket increased by over 5°C within 15 seconds. @*Conclusion@#The use of diode laser irradiation for bracket debonding should be carefully considered because the pulp cavity temperature increases by over 5°C within the irradiation time for resin thermal softening.

Effects of an electric toothbrush combined with 3-color light-emitting diodes on antiplaque and bleeding control: a randomized controlled study

Purpose@#This randomized controlled study aimed to evaluate the effects of an electric toothbrush with 3 colors of light-emitting diodes (LEDs) on antiplaque and bleeding control. @*Methods@#This randomized, placebo-controlled, double-blinded, parallel-group clinical trial included 50 healthy adults with gingivitis, who were randomly assigned to 2 groups. The experimental group used electric toothbrushes with 3 colors of LEDs and the control group used the same electric toothbrush as the experimental group, but with LED sources with one-hundredth of the strength. The subjects used the electric toothbrush 3 times a day for 4 minutes each time. As clinical indices, bleeding on marginal probing (BOMP), the LöeSilness gingival index (GI), and the Turesky-Quigley-Hein plaque index (QHI) were assessed at baseline, at 3 weeks, and at 6 weeks. @*Results@#There were significant decreases in all clinical indices (BOMP, GI, QHI) in both the experimental and control groups compared to baseline at 3 weeks and at 6 weeks. In a comparison between the experimental and control groups, no statistically significant differences were observed for any clinical indices at 3 weeks (P>0.05). However, at 6 weeks, statistically significant differences were observed between the experimental and control groups in BOMP and GI, which are indicators of gingival inflammation (P<0.05). @*Conclusions@#This study demonstrated that an electric toothbrush combined with 3-color LEDs reduced gingival bleeding and inflammation after 6 weeks.

Effects of an electric toothbrush combined with 3-color light-emitting diodes on antiplaque and bleeding control: a randomized controlled study

Purpose@#This randomized controlled study aimed to evaluate the effects of an electric toothbrush with 3 colors of light-emitting diodes (LEDs) on antiplaque and bleeding control. @*Methods@#This randomized, placebo-controlled, double-blinded, parallel-group clinical trial included 50 healthy adults with gingivitis, who were randomly assigned to 2 groups. The experimental group used electric toothbrushes with 3 colors of LEDs and the control group used the same electric toothbrush as the experimental group, but with LED sources with one-hundredth of the strength. The subjects used the electric toothbrush 3 times a day for 4 minutes each time. As clinical indices, bleeding on marginal probing (BOMP), the LöeSilness gingival index (GI), and the Turesky-Quigley-Hein plaque index (QHI) were assessed at baseline, at 3 weeks, and at 6 weeks. @*Results@#There were significant decreases in all clinical indices (BOMP, GI, QHI) in both the experimental and control groups compared to baseline at 3 weeks and at 6 weeks. In a comparison between the experimental and control groups, no statistically significant differences were observed for any clinical indices at 3 weeks (P>0.05). However, at 6 weeks, statistically significant differences were observed between the experimental and control groups in BOMP and GI, which are indicators of gingival inflammation (P<0.05). @*Conclusions@#This study demonstrated that an electric toothbrush combined with 3-color LEDs reduced gingival bleeding and inflammation after 6 weeks.

The effect of periodontal and prosthodontic therapy on glycemic control in patients with diabetes

PURPOSE: To evaluate the effect of periodontal and prosthodontic therapy on glycated hemoglobin A(HbA1c) level in patients with diabetes. MATERIALS AND METHODS: This is a retrospective study of 70 patients suffering from diabetes who visited the Kyungpook National University Hospital between January 2016 and May 2018. Patients underwent medical evaluation for their routine check-up, which includes laboratory test for HbA1c levels. Among the 70 patients, 35 patients also visited Kyungpook National University Dental Hospital during the same period to receive periodontal and prosthodontic therapy, while the other 35 patients did not receive such therapy. The HbA1c levels were compared before and after periodontal and prosthodontic therapy. Comparisons between groups and within groups were performed using independent t-test. RESULTS: The HbA1c levels in the group who have received periodontal and prosthodontic therapy decreased from 7.2 to 6.7 (P=.001). The HbA1c levels in the control group decreased from 7.2 to 7.1 (P=.580). The difference in changes between the two patient groups was statistically significant (P=.011). CONCLUSION: Periodontal and prosthodontic therapy can be effective on glycemic control in patients with diabetes.

3-dimensional analysis about the effects of aging and risk factors on changes in oral environment

PURPOSE: The purpose of this study is to investigate the effects of aging and various risk factors on the oral environment and to analyze them in 3-dimensions. MATERIALS AND METHODS: A total of 800 patients were enrolled in this study, and subjects were divided into 4 groups by age-under 55, 56 – 65, 66 – 75, and over 76. Based on their most recent visit, the number of crowns, bridges, implants, and the remaining natural teeth were recorded. Smoking habits, along with presence of diabetes and hypertension, were surveyed, as risk factors were also set as a variable. Comparisons among the groups or within the groups were performed by independent t-test, and one-way and two-way ANOVA. Kruskal-Wallis test and Mann-Whitney U test were used for analysis. It was assumed to be statistically significant when P value is below .05. RESULTS: Changes in the number of crowns, bridges, implants, and the remaining natural teeth by age were statistically significant. When we examined the effect of risk factors on the change of variables with age, hypertension was found to affect the number of bridges. Diabetes and smoking were found to affect the number of the remaining natural teeth. The other variables were not statistically significant. CONCLUSION: Aging is considered to be an important variable affecting the change of oral environment. Among the risk factors, the presence of smoking habit and diabetes is thought to have a great influence on the change of the number of the remaining natural teeth.

The antiplaque and bleeding control effects of a cetylpyridinium chloride and tranexamic acid mouth rinse in patients with gingivitis

PURPOSE: This study aimed to evaluate the effects of a cetylpyridinium chloride (CPC) and tranexamic acid (TXA) mouth rinse on patients with gingivitis. METHODS: This randomized, placebo-controlled, double-blind, parallel-group, clinical trial included 45 healthy adults with gingivitis, who were randomized into 2 groups. The experimental group used a 0.05% CPC and 0.05% TXA mouth rinse, and the control group used a placebo mouth rinse. The following clinical indices were assessed at baseline, at 3 weeks, and at 6 weeks: the Turesky-Quigley-Hein plaque index (QHI), the Löe-Silness gingival index (GI), and bleeding on marginal probing (BOMP). The subjects used the mouth rinse during the experimental period for 20 seconds, 4–5 times daily (10 mL each time). RESULTS: There were no significant differences in the clinical indices between the groups at baseline. In the experimental group (CPC+TXA), a statistically significant improvement was evident in the QHI, GI, and BOMP at 3 and 6 weeks. These results were similar to those observed in the control group at 3 and 6 weeks, although the change in BOMP was not statistically significant in that group. At 6 weeks, the experimental group had a significantly lower mean score for the QHI than the control group. CONCLUSIONS: This study demonstrated that a CPC and TXA mouth rinse exhibited significant antiplaque and anti-gingivitis efficacy, and had a positive effect on bleeding control when used daily for 6 weeks.

Long-term evaluations of teeth and dental implants during dental maintenance period

PURPOSE: This study was designed to evaluate the teeth and dental implants during dental maintenance therapy over 3 years in different conditions after periodontal and dental prosthetic treatment. MATERIALS AND METHODS: 166 patients received maintenance therapy. 59 patients were treated with 2% minocycline-HCl ointment as local drug delivery (LDD) (L group) and 107 patients were treated without LDD (NL group). Clinical data was collected in maintenance period for evaluation. Patients were classified into groups depending on the application of LDD with maintenance therapy, the type of dental treatment before maintenance period (Pre-Tx), the frequency (F-MT), and regularity (R-MT) of maintenance therapy. RESULTS: The numbers of lost teeth (N-teeth, P=.003) and newly placed dental implants (N-implants, P=.022) are significantly different according to Pre-Tx. F-MT among patients who received surgical dental treatment before maintenance period showed statistical differences in N-teeth (P=.041), but not in N-implants (P=.564). All of the patients in L group showed high F-MT (F-MT1). In NL group, there were no statistical differences in N-teeth or N-implants according to F-MT or R-MT. In F-MT1 group, application of LDD made N-teeth significantly different from both Pre-Tx groups while no significant difference could be found in N-implant. Independent t-test and one-way ANOVA were selected for statistical analysis. CONCLUSION: The regular maintenance therapy and LDD can be effective for teeth during maintenance period. It is not only pharmacological efficacy in decreasing bacterial species that makes LDD a useful adjunct. Application of LDD also motivates patients to take adequate check-ups in the aspects of both frequency and regularity.

Long-term evaluations of teeth and dental implants during dental maintenance period

PURPOSE: This study was designed to evaluate the teeth and dental implants during dental maintenance therapy over 3 years in different conditions after periodontal and dental prosthetic treatment. MATERIALS AND METHODS: 166 patients received maintenance therapy. 59 patients were treated with 2% minocycline-HCl ointment as local drug delivery (LDD) (L group) and 107 patients were treated without LDD (NL group). Clinical data was collected in maintenance period for evaluation. Patients were classified into groups depending on the application of LDD with maintenance therapy, the type of dental treatment before maintenance period (Pre-Tx), the frequency (F-MT), and regularity (R-MT) of maintenance therapy. RESULTS: The numbers of lost teeth (N-teeth, P=.003) and newly placed dental implants (N-implants, P=.022) are significantly different according to Pre-Tx. F-MT among patients who received surgical dental treatment before maintenance period showed statistical differences in N-teeth (P=.041), but not in N-implants (P=.564). All of the patients in L group showed high F-MT (F-MT1). In NL group, there were no statistical differences in N-teeth or N-implants according to F-MT or R-MT. In F-MT1 group, application of LDD made N-teeth significantly different from both Pre-Tx groups while no significant difference could be found in N-implant. Independent t-test and one-way ANOVA were selected for statistical analysis. CONCLUSION: The regular maintenance therapy and LDD can be effective for teeth during maintenance period. It is not only pharmacological efficacy in decreasing bacterial species that makes LDD a useful adjunct. Application of LDD also motivates patients to take adequate check-ups in the aspects of both frequency and regularity.

Long-term evaluation of teeth and implants during the periodic maintenance in patients with viral liver disease

PURPOSE: This study was designed to investigate the maintenance of teeth and implants in patients with viral liver disease. MATERIALS AND METHODS: 316 patients without any significant systemic disease were selected as a control group. Liver disease group was consisted of 230 patients. Necessary data were collected using clinical records and panoramic radiographs. Then, the patients were subdivided into 2 groups based on the type of active dental therapy received before maintenance period (Pre-Tx). Analysis for finding statistically significant difference was performed based on the need for re-treatment of active dental therapy (Re-Tx) and change in the number of teeth (N-teeth) and implants (N-implants). RESULTS: Comparing to control group, the patients with liver disease showed higher value on N-teeth, N-implants, and Re-Tx. Statistically significant differences were found on N-teeth (P=.000) and Re-Tx (P=.000) in patients with non-surgical Pre-Tx. Analysis based on severity of liver disease showed that N-teeth and Re-Tx were directly related to severity of liver disease regardless of received type of Pre-Tx. Significant differences were found on N-teeth (P=.003) and Re-Tx (P=.044) in patients with non-surgical Pre-Tx. CONCLUSION: In this study, it was concluded that liver disease might influence the loss of teeth and cause the relapse of dental disease during maintenance period in patients. A significant positive relationship between tooth and implant loss and severity of liver disease seems to exist.

Detection of Bacterial Species in Chronic Periodontitis Tissues at Different Stages of Disease Severity

The goal of this research was to determine the relationship between the stage of chronic periodontitis and the presence of six bacterial pathogens (Aggregatibacter actinomycetemcomitans: AA, Fusobacterium nucleatum: FN, Porphyromonas gingivalis: PG, Prevotella intermedia: PI, Enterococcus faecalis: EF, and Parvimonas micra: PM). Forty-six chronic periodontitis patients visiting a dental hospital were included in this investigation. They were classified into four chronic periodontitis stages based on the sulcus bleeding index value and the probing depth. The tissue samples from the periodontal surgery were used for a direct PCR detection assay. A total of 49 samples from 46 patients were collected and classified into four chronic periodontitis groups (N: 6, P1: 13, P2: 18, P3: 12). The PCR assay showed that FN, PI, and PM were involved from the beginning of chronic periodontitis (P1), while AA and PG existed regardless of the disease stages. EF was strongly linked to the P3 stage of the disease. In order to assess the effect of dental treatments on patients with chronic periodontitis, EF should be a critical marker for P3 patients, while FN, PI, and PM would be good indicators for chronic periodontitis.

Relationship of tooth mortality and implant treatment in Type 2 diabetes mellitus patients in Korean adults

PURPOSE: The purpose of this study was to to analyze the effect of Type 2 diabetes on tooth mortality, implant treatment and prosthetic status. MATERIALS AND METHODS: 275 Type 2 diabetics and 300 non-diabetics, aged 40-80 years were selected for analysis. The assessment of number of teeth, missing teeth, fixed prostheses (bridge pontics), implants using panoramic radiographs and dental records were carried out. RESULTS: Diabetes mellitus (DM) patients had a higher number of missing teeth (P<.05) and placed implants (P=.074), age (P<.05), male gender percentage (P=.042), smoker percentage (P<.05) than non-DM patients. In univariate analysis, the patients in older group showed significantly higher number of tooth loss rate at the first dental examination than the patients in younger group. Tooth loss rate of smokers did not show higher value than that of non-smokers. When multiple variables including DM, age, smoking, gender were considered together, diabetics and older group patients showed significantly higher tooth loss rate at the first dental examination than non-diabetics and younger group patients, respectively. Smokers and male group did not show a significant difference than non-smokers and female group, respectively. CONCLUSION: Tooth mortality and implant treatment rate were significantly higher in the DM group as indicated by univariate and multivariate logistic regression analysis. Old age groups showed significantly higher odds ratios and tooth loss rate. As diabetics showed the higher tooth loss rate than non-diabetics, diabetics also had more implant restorations than non-diabetics.

The effects of dexamethasone on the apoptosis and osteogenic differentiation of human periodontal ligament cells

PURPOSE: The purpose of the current study was to examine the effect of dexamethasone (Dex) at various concentrations on the apoptosis and mineralization of human periodontal ligament (hPDL) cells. METHODS: hPDL cells were obtained from the mid-third of premolars extracted for orthodontic reasons, and a primary culture of hPDL cells was prepared using an explant technique. Groups of cells were divided according to the concentration of Dex (0, 1, 10, 100, and 1,000 nM). A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed for evaluation of cellular viability, and alkaline phosphatase activity was examined for osteogenic differentiation of hPDL cells. Alizarin Red S staining was performed for observation of mineralization, and real-time polymerase chain reaction was performed for the evaluation of related genes. RESULTS: Increasing the Dex concentration was found to reduce cellular viability, with an increase in alkaline phosphatase activity and mineralization. Within the range of Dex concentrations tested in this study, 100 nM of Dex was found to promote the most vigorous differentiation and mineralization of hPDL cells. Dex-induced osteogenic differentiation and mineralization was accompanied by an increase in the level of osteogenic and apoptosis-related genes and a reduction in the level of antiapoptotic genes. The decrease in hPDL cellular viability by glucocorticoid may be explained in part by the increased prevalence of cell apoptosis, as demonstrated by BAX expression and decreased expression of the antiapoptotic gene, Bcl-2. CONCLUSIONS: An increase in hPDL cell differentiation rather than cellular viability at an early stage is likely to be a key factor in glucocorticoid induced mineralization. In addition, apoptosis might play an important role in Dex-induced tissue regeneration; however, further study is needed for investigation of the precise mechanism.

The expression of a nitric oxide derivative, tissue inhibitors of metalloproteinase-3, and tissue inhibitors of metalloproteinase-4 in chronic periodontitis with type 2 diabetes mellitus

PURPOSE: The purpose of this study was to analyze the expression of inducible nitric oxide synthases (iNOS), tissue inhibitors of metalloproteinase (TIMP)-3, and TIMP-4 in the gingival tissues of periodontal patients with or without type 2 diabetes mellitus (DM). METHODS: Depending on the patient's systemic condition and clinical criteria of the gingiva, each gingival sample was classified into one of three groups. Sixteen clinically, systemically healthy patients (group 1), 16 periodontal patients (group 2), and 16 periodontal patients with DM (group 3) were included. Tissue samples in each group were collected, prepared, and analyzed by western blotting. Quantification of the relative amount of TIMP-3, TIMP-4, and iNOS was performed. RESULTS: The expression levels of iNOS and TIMP-3 both increased in group 1, group 2, and group 3 in increasing order, and were significantly higher in both group 2 and group 3 as compared to group 1 (P<0.05). The expression levels of TIMP-4 increased in the same order, but significantly increased in group 2 as compared to group 1, in group 3 as compared to group 1, and group 3 as compared to group 2 (P<0.05). CONCLUSIONS: This study demonstrated that iNOS, TIMP-3, and TIMP-4 might be involved in the progression of periodontal inflammation associated with type 2 DM. It is thought that further study of these factors can be applied practically for the diagnosis and control of periodontitis in diabetics.

Influence of crown-to-implant ratio on periimplant marginal bone loss in the posterior region: a five-year retrospective study

PURPOSE: The aim of this study was to evaluate the influence of the crown-to-implant (C/I) ratio on the change in marginal bone level around the implant and to determine the site-related factors influencing the relationship between the C/I ratio and periimplant marginal bone loss. METHODS: A total of 259 implants from 175 patients were evaluated at a mean follow-up of five years. Implants were divided into two groups according to their C/I ratios: 1. Site-related factors having an influence on the relationship between C/I ratio and periimplant marginal bone loss were analyzed according to the implant location, implant diameter, implant manufacturer, prosthesis type, and guided bone regeneration (GBR) procedure. RESULTS: It was found that 1) implants with a C/I ratio below 1 exhibited greater periimplant marginal bone loss than implants with a C/I ratio more than 1, 2) site-related factors had an effect on periimplant marginal bone loss, except for the implant system used, 3) the C/I ratio was the factor having more dominant influence on periimplant marginal bone loss, compared with implant diameter, prosthesis type, implant location, and GBR procedure, 4) implants with a C/I ratio below 1 showed greater periimplant marginal bone loss than implants with a C/I ratio greater than 1 in the maxilla, but not in the mandible, 5) and periimplant marginal bone loss was more affected by the implant system than the C/I ratio. CONCLUSIONS: Within the limitations of this study, implants with a higher C/I ratio exhibited less marginal bone loss than implants with a lower C/I ratio in the posterior regions. The C/I ratio was a more dominant factor affecting periimplant marginal bone loss in the maxilla than the mandible. Meanwhile, the implant system was a more dominant factor influencing periimplant marginal bone loss than the C/I ratio.

The influence of type 2 diabetes mellitus on the expression of inflammatory mediators and tissue inhibitor of metalloproteinases-2 in human chronic periodontitis

PURPOSE: The purpose of this study was to compare and quantify the expression of C-reactive protein (CRP), matrix metalloproteinase (MMP)-14, and tissue inhibitor of metalloproteinases (TIMP)-2 in gingival tissues of patients with chronic periodontitis accompanied with inflammatory reaction related to alveolar bone resorption with or without type 2 diabetes mellitus (DM). METHODS: Twelve patients with type 2 DM and chronic periodontitis (group 3), twelve patients with chronic periodontitis (group 2), and twelve healthy individuals (group 1) were included in the study. Gingival tissue biopsies were collected from each patient and from healthy individuals at the time of periodontal surgery (including surgical crown lengthening) or tooth extraction. The concentrations of cytokines were determined by a western blot analysis. RESULTS: The expression levels of CRP and MMP-14 increased in group 2 and 3, and they were highest in group 3. The expressions of TIMP-2 also increased in group 2 and 3. CONCLUSIONS: This study demonstrated that the expression levels of CRP, MMP-14, and TIMP-2 might be inflammatory markers in periodontal inflamed tissue. It can be assumed that CRP, MMP-14, and TIMP-2 may be partly involved in the progression of periodontal inflammation associated to type 2 DM.

Comparative study on the cellular activities of osteoblast-like cells and new bone formation of anorganic bone mineral coated with tetra-cell adhesion molecules and synthetic cell binding peptide

PURPOSE: We have previously reported that tetra-cell adhesion molecule (T-CAM) markedly enhanced the differentiation of osteoblast-like cells grown on anorganic bone mineral (ABM). T-CAM comprises recombinant peptides containing the Arg-Gly-Asp (RGD) sequence in the tenth type III domain, Pro-His-Ser-Arg-Asn (PHSRN) sequence in the ninth type III domain of fibronectin (FN), and the Glu-Pro-Asp-Ilu-Met (EPDIM) and Tyr-His (YH) sequence in the fourth fas-1 domain of betaig-h3. Therefore, the purpose of this study was to evaluate the cellular activity of osteoblast-like cells and the new bone formation on ABM coated with T-CAM, while comparing the results with those of synthetic cell binding peptide (PepGen P-15). METHODS: To analyze the cell viability, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed, andto analyze gene expression, northernblot was performed. Mineral nodule formations were evaluated using alizarin red stain. The new bone formations of each group were evaluated using histologic observation and histomorphometrc analysis. RESULTS: Expression of alkaline phosphatase mRNA was similar in all groups on days 10 and 20. The highest expression of osteopontin mRNA was observed in the group cultured with ABM/P-15, followed by those with ABM/T-CAM and ABM on days 20 and 30. Little difference was seen in the level of expression of collagen type I mRNA on the ABM, ABM/T-CAM, and ABM/P-15 cultured on day 20. There were similar growth and proliferation patterns for the ABM/T-CAM and ABM/P-15. The halo of red stain consistent with Ca2+ deposition was wider and denser around ABM/T-CAM and ABM/P-15 particles than around the ABM particles. The ABM/T-CAM group seemed to have bone forming bioactivity similar to that of ABM/P-15. A complete bony bridge was seen in two thirds of the defects in the ABM/T-CAM and ABM/P-15 groups. CONCLUSIONS: ABM/T-CAM, which seemed to have bone forming bioactivity similar to ABM/P-15, was considered to serve as effective tissue-engineered bone graft material.

Gene expression pattern during osteogenic differentiation of human periodontal ligament cells in vitro

PURPOSE: Periodontal ligament (PDL) cell differentiation into osteoblasts is important in bone formation. Bone formation is a complex biological process and involves several tightly regulated gene expression patterns of bone-related proteins. The expression patterns of bone related proteins are regulated in a temporal manner both in vivo and in vitro. The aim of this study was to observe the gene expression profile in PDL cell proliferation, differentiation, and mineralization in vitro. METHODS: PDL cells were grown until confluence, which were then designated as day 0, and nodule formation was induced by the addition of 50 microg/mL ascorbic acid, 10 mM beta-glycerophosphate, and 100 nM dexamethasone to the medium. The dishes were stained with Alizarin Red S on days 1, 7, 14, and 21. Real-time polymerase chain reaction was performed for the detection of various genes on days 0, 1, 7, 14, and 21. RESULTS: On day 0 with a confluent monolayer, in the active proliferative stage, c-myc gene expression was observed at its maximal level. On day 7 with a multilayer, alkaline phosphatase, bone morphogenetic protein (BMP)-2, and BMP-4 gene expression had increased and this was followed by maximal expression of osteocalcin on day 14 with the initiation of nodule mineralization. In relationship to apoptosis, c-fos gene expression peaked on day 21 and was characterized by the post-mineralization stage. Here, various genes were regulated in a temporal manner during PDL fibroblast proliferation, extracellular matrix maturation, and mineralization. The gene expression pattern was similar. CONCLUSIONS: We can speculate that the gene expression pattern occurs during PDL cell proliferation, differentiation, and mineralization. On the basis of these results, it might be possible to understand the various factors that influence PDL cell proliferation, extracellular matrix maturation, and mineralization with regard to gene expression patterns.