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Purpose Some systemic conditions, especially diabetes mellitus (DM), adversely affect dental implant success. This study aimed to investigate the effects of ibuprofen-loaded TiO2 nanotube (ILTN) dental implants in alloxan-induced diabetic rabbits. Methods Twenty-six New Zealand white rabbits were treated with alloxan monohydrate to induce DM. At 2 weeks following DM induction, 3 types of implants (sandblasted, large-grit, and acid-etched [SLA], ILTN, and machined) were placed into the proximal tibia in the 10 rabbits that survived following DM induction. Each type of implant was fitted randomly in 1 of the holes (round-robin method). The animals were administered alizarin (at 3 weeks) and calcein (at 6 weeks) as fluorescent bone markers, and were sacrificed at 8 weeks for radiographic and histomorphometric analyses. Results TiO2 nanotube arrays of ~70 nm in diameter and ~17 μm in thickness were obtained, and ibuprofen was loaded into the TiO2 nanotube arrays. A total of 26 rabbits were treated with alloxan monohydrate and only 10 rabbits survived. The 10 surviving rabbits showed a blood glucose level of 300 mg/dL or higher, and the implants were placed in these diabetic rabbits. The implant stability quotient (ISQ) and bone-to-implant contact (BIC) values were significantly higher in the ILTN group (ISQ: 61.8, BIC: 41.3%) and SLA group (ISQ: 62.6, BIC: 46.3%) than in the machined group (ISQ: 53.4, BIC: 20.2%), but the difference in the BIC percentage between the SLA and ILTN groups was not statistically significant (P=0.628). However, the bone area percentage was significantly higher in the ILTN group (78.0%) than in the SLA group (52.1%; P=0.000). Conclusions The ILTN dental implants showed better stability (ISQ) and BIC than the machined implants; however, these values were similar to the commercially used SLA implants in the 2-week diabetic rabbit model., Graphical Abstract

This study aimed to compare the long-term survival rate and peri-implant marginal bone loss between different types of dental implant-abutment connections.Implants with external or internal abutment connections, which were fitted at Gangneung-Wonju National University Dental Hospital from November 2011 to December 2015 and followed up for5 years, were retrospectively investigated. Cumulative survival rates were evaluated for5 years, and peri-implant marginal bone loss was evaluated at 1- and 5-year follow-up examinations after functional loading.The 8-year cumulative survival rates were 93.3% and 90.7% in the external and internal connection types, respectively (There was no significant difference in the cumulative survival rate between implants with external and internal abutment connections. After 1 year of loading, marginal bone loss was greater around the implants with an external abutment connection. However, no significant difference between the external and internal connection groups was found after 5 years. Both types of abutment connections are viable treatment options for the reconstruction of partially edentulous ridges.

This study aimed to characterize the early stages of periodontal disease and determine the optimal period for its evaluation in a mouse model. The association between the duration of ligation and its effect on the dentogingival area in mice was evaluated using micro-computed tomography (CT) and histological analysis.Ninety mice were allocated to an untreated control group or a ligation group in which periodontitis was induced by a 6-0 silk ligation around the left second maxillary molar. Mice were sacrificed at 1, 2, 3, 4, 5, 8, 11, and 14 days after ligature placement. Alveolar bone destruction was evaluated using micro-CT. Histological analysis was performed to assess the immune-inflammatory processes in the periodontal tissue.No significant difference in alveolar bone loss was found compared to the control group until day 3 after ligature placement, and a gradual increase in alveolar bone loss was observed from 4 to 8 days following ligature placement. No significant between-group differences were observed after 8 days. The histological analysis demonstrated that the inflammatory response was evident from day 4.Our findings in a mouse model provide experimental evidence that ligature-induced periodontitis models offer a consistent progression of disease with marginal attachment down-growth, inflammatory infiltration, and alveolar bone loss.

The purpose of this study was to evaluate the antimicrobial effects of photothermal therapy using indocyanine green (ICG) and an 810-nm infrared diode laser on Streptococcus gordonii biofilm attached to zirconia surfaces in vitro.A biofilm was formed using the static method on zirconia disks placed in a 24-well plate. The biofilms were subdivided into the following six treatment groups: control, commercial photodynamic therapy (PDT), chlorhexidine gluconate (CHX), laser only (L, 810-nm infrared diode), ICG, and laser with ICG (PTT). After treatment, each disk was agitated and the solution with detached bacteria was spread directly on a blood agar plate. Cells were cultured under anaerobic conditions and colony-forming units were counted. Confocal laser-scanning microscopy was used to assess the survival according to the height of the biofilm.The PTT, PDT, and CHX groups showed a significant reduction in S. gordonii viability (p0.05), while the L and ICG groups showed no significant difference compared to the control group (p = 0.32, p = 0.97; respectively). In confocal laser-scanning microscopy images, the PTT, PDT, and CHX groups presented most of the dead bacteria in both the upper and lower levels of biofilm.Within the limitations of this in vitro study, PTT with ICG was effective in significantly reducing the viability of S. gordonii bacteria on zirconia. Further studies are needed to establish a standardized PTT protocol to treat peri‑implant diseases.

The hydrophilicity of bone graft material generally used as a carrier can play an important role in regulating bone morphogenetic protein (BMP) expression at the bone graft site. The hydrophilicity, altering physicochemical properties, and enhancing biological capabilities, can be increased via surface modification through ultraviolet (UV) photofunctionalization and the effect on de novo osteogenesis could be further improved. Therefore, this study aimed to assess the effects of UV-irradiated TiO2 -coated hydroxyapatite (HA) in combination with rhBMP-2 on bone regeneration in rabbit calvarial defects. The hydrophilicity of HA and TiO2 -coated HA pellets was evaluated by measuring the contact angle of water droplets with UV irradiation. To compare de novo osteogenesis in rabbit calvarial defects, the rabbits were segregated into four different groups: negative control, HA, TiO2 -coated HA, and TiO2 -coated HA with UV; histomorphometric analysis and micro-computed tomography (μCT) imaging were performed after 4 and 8 weeks. In vivo analysis revealed that de novo osteogenesis occurred on the critical size defects in all groups and was significantly increased in the TiO2 -coated HA with UV group than in other groups (p < 0.05). The present results indicate that UV photofunctionalization promotes de novo osteogenesis. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 1953-1959, 2019.

Purpose This study aimed to evaluate the clinical and microbiological efficacy of adjunctive local delivery of minocycline (Periocline®) in patients receiving supportive periodontal therapy (SPT) after initial treatment. Methods The participants were 16 men and 8 women (age, 20–65 years) who had at least 15 natural teeth, underwent SPT for more than 1 year due to chronic periodontitis, had 4 or more periodontal pocket sites deeper than 5 mm, and showed >25% gingival bleeding on probing (BoP). They were randomly assigned to the test and control groups. In the test group, mechanical debridement and local antibiotic delivery were performed for all periodontal sulci/pockets; in the control group, mechanical debridement and saline irrigation were performed. In patients who underwent SPT for more than 1 year, clinical and microbiological examinations were performed at baseline and 1 and 3 months after SPT. The clinical examination included an assessment of the periodontal pocket depth, clinical attachment level, plaque index, and BoP. Microbial tests were performed using real-time polymerase chain reaction; the relative ratios of Porphyromonas gingivalis and Fusobacterium nucleatum were determined. Results Both groups showed significant improvements in clinical parameters at 1 and 3 months from baseline; there were no significant changes between months 1 and 3. Intergroup differences were insignificant. The microbiological analysis revealed no significant differences in P. gingivalis and F. nucleatum ratios across time points. While intergroup differences were insignificant, there was a tendency for the P. gingivalis and F. nucleatum ratios to decrease in the test group. Conclusions Mechanical debridement in patients receiving maintenance therapy resulted in clinically significant improvement; the effectiveness of additional local delivery of antibiotics was not significant. The ratios of P. gingivalis and F. nucleatum showed a tendency to decrease in the test group, although it was not significant., Graphical Abstract

The aim of this study was to evaluate the antimicrobial effect of photodynamic therapy (PDT) on biofilm attached to sandblasted and acid-etched (SLA) surfaces. The bacterial strains used were Aggregatibacter actinomycetemcomitans and Streptococcus sanguinis. SLA disks were subdivided into five groups including one control group and four test groups (laser-alone, methylene blue (MB)-alone, PDT60, and PDT120) for PDT examination for each surface. The laser-alone group was only irradiated with a diode laser for 60 s. The MB-alone group was put into 1 ml of 100 μg/ml of methylene blue for 60 s. PDT60 and PDT120 groups were put into 1 ml of 100 μg/ml methylene blue and then irradiated for 60 and 120 s, respectively. After treatment, the survival rate of bacteria was determined by counting the colony-forming units (CFUs) after incubation. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were used to observe the microorganisms on the disk surfaces. Significant differences were found between the control group, LED-alone group, MB-alone group, and PDT60 and PDT120 groups (P

Purpose The purpose of this study was to compare the characteristics of single- and dual-species in vitro oral biofilms made by static and dynamic methods. Methods Hydroxyapatite (HA) disks, 12.7 mm in diameter and 3 mm thick, were coated with processed saliva for 4 hours. The disks were divided into a static method group and a dynamic method group. The disks treated with a static method were cultured in 12-well plates, and the disks in the dynamic method group were cultured in a Center for Disease Control and Prevention (CDC) biofilm reactor for 72 hours. In the single- and dual-species biofilms, Fusobacterium nucleatum and Porphyromonas gingivalis were used, and the amount of adhering bacteria, proportions of species, and bacterial reduction of chlorhexidine were examined. Bacterial adhesion was examined with scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). Results Compared with the biofilms made using the static method, the biofilms made using the dynamic method had significantly lower amounts of adhering and looser bacterial accumulation in SEM and CLSM images. The proportion of P. gingivalis was higher in the dynamic method group than in the static method group; however, the difference was not statistically significant. Furthermore, the biofilm thickness and bacterial reduction by chlorhexidine showed no significant differences between the 2 methods. Conclusions When used to reproduce periodontal biofilms composed of F. nucleatum and P. gingivalis, the dynamic method (CDC biofilm reactor) formed looser biofilms containing fewer bacteria than the well plate. However, this difference did not influence the thickness of the biofilms or the activity of chlorhexidine. Therefore, both methods are useful for mimicking periodontitis-associated oral biofilms., Graphical Abstract

Although increasing evidence indicates that serotonin (SER; 5-hydroxytrypamine [5-HT]) is involved in the regulation of bone metabolism, conflicting data exist regarding whether SER promotes or inhibits osteoblast differentiation and bone formation. Regeneration of functional bone is required for proper osseointegration of dental implants. Noticeably, the use of selective SER reuptake inhibitors was recently associated with the failure of osseointegrated dental implants. The present study examines the direct role of peripheral SER on the regulation of bone regeneration.The effect of SER on osteoblast differentiation and bone regeneration was examined using rat calvarial cell cultures in vitro and a rat critical-sized calvarial defect model in vivo.Rat calvarial cells expressed SER receptors Htr1 (5-HT1) and Htr2 (5-HT2), which are known to transmit signals in bone cells. In vitro, SER significantly reduced osteogenic differentiation and mineralization of rat calvarial cells with concomitant reduction of osteoblast marker genes including alkaline phosphatase (Alpl), osterix (Sp7), and osteocalcin (Bglap). Histologic and radiologic analyses using the rat critical-sized calvarial defect model revealed that the existence of SER significantly inhibited β-phase tricalcium phosphate-induced bone regeneration.Results suggest that SER in the local bone microenvironment might play a negative role in osteoblast differentiation and bone formation in rats.

Purpose: The aim of this study was to evaluate whether fluorides at various pH cause changes in the surface roughness of titanium implants that alter the adherence of bacterial biofilms. Materials and Methods: The titanium disks were assigned randomly to the following seven groups according to the fluoride agents and application time (1 minute or 30 minute) used: control (no treatment); group 1 (1.23% acidulated phosphate fluoride [APF] at pH 3.5 for 1 minute); group 2 (1.23% APF at pH 3.5 for 30 minute); group 3 (1.23% APF at pH 4.0 for 1 minute); group 4 (1.23% APF at pH 4.0 for 30 minute); group 5 (2% NaF gel at pH 7.0 for 1 minute); group 6 (2% NaF gel at pH 7.0 for 30 minute). The surface roughness of the titanium disks and the amount of adherent bacteria were measured. Results: Group 2 showed a significantly greater surface roughness than the control group (P < 0.0001). No significant differences in the amount of surface bacteria were observed between the treated samples and the controls. In addition, there were no significant differences in bacterial adherence relative to the incubation period between the treated samples and the controls. Conclusion: The surface roughness of the titanium disks was significantly greater after treatment with APF at pH 3.5 for 30 min compared with that of the controls. In addition, we found that the amount of Porphyromonas gingivalis, Fusobacterium nucleatum, and Aggregatibactor actinomycetemcomitans was similar among all groups.

Purpose The purpose of this study was to evaluate the optimal diabetes duration for bone regeneration experiments in an alloxan monohydrate (ALX)–induced diabetic rabbit calvarial defect model by evaluating the association between diabetes duration and bone healing capacity. Methods Twenty-four New Zealand white rabbits were used. Twenty-two rabbits were injected with 100 mg/kg of ALX to induce experimental diabetes. These rabbits were divided into 4 groups, including a control group and groups with diabetes durations of 1 week (group 1), 2 weeks (group 2), and 4 weeks (group 3). Calvarial defects were created at 1, 2, and 4 weeks after ALX injection and in the control rabbits. Cone-beam computed tomography (CBCT) scanning was performed on the day of surgery and at 2 and 4 weeks after surgery. The rabbits were sacrificed 4 weeks after surgery, followed by histological and immunofluorescence analysis. Results The diabetic state of all diabetic rabbits was well-maintained throughout the experiment. Reconstructed 3-dimensional CBCT imaging showed more rapid and prominent bone regeneration in the control group than in the experimental groups. Histological staining showed notable bone regeneration in the control group, in contrast to scarce bone formation in the experimental groups. The appearance and immunoreactivity of receptor activator of nuclear factor-kappa B and osteoprotegerin did not show notable differences among the groups. Conclusion ALX administration at 100 mg/kg successfully induced experimental diabetes in rabbits. The effect of diabetes on bone healing was evident when the interval between diabetes induction and the intervention was ≥1 week., Graphical Abstract

The hydrophilicity of bone graft material generally used as a carrier can play an important role in regulating bone morphogenetic protein (BMP) expression at the bone graft site. The hydrophilicity, altering physicochemical properties, and enhancing biological capabilities, can be increased via surface modification through ultraviolet (UV) photofunctionalization and the effect on de novo osteogenesis could be further improved. Therefore, this study aimed to assess the effects of UV-irradiated TiO

Purpose The aim of this study was to evaluate the antimicrobial effect of a newly devised toothbrush with light-emitting diodes (LEDs) on Porphyromonas gingivalis attached to sandblasted and acid-etched titanium surfaces. Methods The study included a control group, a commercial photodynamic therapy (PDT) group, and 3 test groups (B, BL, and BLE). The disks in the PDT group were placed in methylene blue and then irradiated with a diode laser. The B disks were only brushed, the BL disks were brushed with an LED toothbrush, and the BLE disks were placed into erythrosine and then brushed with an LED toothbrush. After the different treatments, bacteria were detached from the disks and spread on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy was performed to visualize bacterial alterations. Results The number of viable bacteria in the BLE group was significantly lower than that in the other groups (P

The purpose of this report is to suggest clinical managements of implant periapical lesions by presenting three clinical cases managed by either the infected form or the inactive form with the follow-up period of five to twelve years. One patient with no clinical symptom was regarded as inactive form. Two patients having pain were regarded as infected form and have been under the systemic antibiotic therapy. In one patient, the symptom subsided and the size of radiolucent lesion decreased. However, the other patient showed increased size of lesion causing the implant unstable, which leaded to remove the implant and to replace it. There was neither additional increase of the lesion nor functional problem for all three. It is important to detect implant periapical lesion in early stage before jeopardizing the stable implant and manage properly using systemic antibiotic therapy and surgical approach if needed, depending on infected form and inactive form.

Purpose The purpose of this study was to evaluate the effect of photodynamic therapy (PDT) using erythrosine and a green light emitting diode (LED) light source on biofilms of Aggregatibacter actinomycetemcomitans attached to resorbable blasted media (RBM) and sandblasted, large-grit, acid-etched (SLA) titanium surfaces in vitro. Methods RBM and SLA disks were subdivided into four groups, including one control group and three test groups (referred to as E0, E30, E60), in order to evaluate the effect of PDT on each surface. The E0 group was put into 500 µL of 20 µM erythrosine for 60 seconds without irradiation, the E30 group was put into erythrosine for 60 seconds and was then irradiated with a LED for 30 seconds, and the E60 group was put into erythrosine for 60 seconds and then irradiated with a LED for 60 seconds. After PDT, sonication was performed in order to detach the bacteria, the plates were incubated under anaerobic conditions on brucella blood agar plates for 72 hours at 37℃, and the number of colony-forming units (CFUs) was determined. Results Significant differences were found between the control group and the E30 and E60 groups (P

Purpose: The aim of the present study was to evaluate the long-term survival of implants retrospectively and determine the risk factors associated with implant failure. Materials and Methods: Of all implants that were placed at the Department of Periodontology of the Dental Hospital of Gangneung-Wonju National University from January 1998 to December 2012, 2265 implants that were followed up until June 2013 were included in this study. Data were collected from clinical and radiographic examinations from previous visits. The information gathered included gender, age, smoking status, implant diameter, implant length, surface of implant, location of implant within the dental arch, surgical techniques and existence of complications. Results: The survival rate before loading was 98.9%. The cumulative survival rate after 5 years of loading was 97.2%, and after 15 years of loading was 95.2%. In a simple logistic regression analysis, gender (P = 0.016), smoking status (P = 0.001), location of implant (P = 0.020) and existence of complications (P = 0.002) were statistically associated with implant failure and included in the multiple regression analysis. As a result of multiple logistic regression analysis, the variables statistically associated with implant failure (P < 0.05) were smoking status (P = 0.049) and existence of complications (P < 0.001). Conclusion: The cumulative survival rate of dental implants after 15 years of loading was 95.2% and that the variables statistically associated with implant failure were smoking status and existence of complications.

Objective The interleukin-17 (IL-17) family is a group of pro-inflammatory cytokines that are produced by a subset of helper T cells. IL-17 family members are not only involved in the immune response of tissues but also play a role in bone metabolism. Although the role of IL-17 in osteoclast-mediated bone resorption has been extensively studied, its role during osteoblast-mediated bone formation has rarely been investigated. In this study, we examined the effect of IL-17 on osteogenesis in rats both in vitro and in vivo . Design To evaluate osteogenesis in vitro , rat calvarial osteoblast precursor cells were cultured for 14 days in osteogenic medium with or without 50ng/mL IL-17. Osteogenic activity was evaluated by alkaline phosphatase and alizarin red staining. The mRNA expression of alkaline phosphatase, osteocalcin, and osterix was also measured by using real-time PCR. To test whether IL-17 affects bone formation in vivo , bone filling was examined by micro-computed tomography and histological observations at 8 weeks after critical-sized defects were made in rat calvaria. Results The presence of IL-17 significantly reduced alkaline phosphatase and alizarin red staining and the expression of alkaline phosphatase, osteocalcin, and osterix in vitro . IL-17 also significantly inhibited the filling of calvarial defects in vivo . Conclusion IL-17 exerted a negative effect on osteogenesis in a rat model. In contrast to the previously reported beneficial effect on osteogenic differentiation of human mesenchymal stem cells, our results suggest a species or cell type-specific role for IL-17 in bone formation.

PURPOSE: The purpose of this study was to compare the phototoxic effects of blue light exposure on periodontal pathogens in both planktonic and biofilm cultures. METHODS: Strains of Aggregatibacter actinomycetemcomitans, Fusobacterium nucleatum, and Porphyromonas gingivalis, in planktonic or biofilm states, were exposed to visible light at wavelengths of 400.520 nm. A quartz-tungsten-halogen lamp at a power density of 500 mW/cm(2) was used for the light source. Each sample was exposed to 15, 30, 60, 90, or 120 seconds of each bacterial strain in the planktonic or biofilm state. Confocal scanning laser microscopy (CSLM) was used to observe the distribution of live/dead bacterial cells in biofilms. After light exposure, the bacterial killing rates were calculated from colony forming unit (CFU) counts. RESULTS: CLSM images that were obtained from biofilms showed a mixture of dead and live bacterial cells extending to a depth of 30-45 µm. Obvious differences in the live-to-dead bacterial cell ratio were found in P. gingivalis biofilm according to light exposure time. In the planktonic state, almost all bacteria were killed with 60 seconds of light exposure to F. nucleatum (99.1%) and with 15 seconds to P. gingivalis (100%). In the biofilm state, however, only the CFU of P. gingivalis demonstrated a decreasing tendency with increasing light exposure time, and there was a lower efficacy of phototoxicity to P. gingivalis as biofilm than in the planktonic state. CONCLUSIONS: Blue light exposure using a dental halogen curing unit is effective in reducing periodontal pathogens in the planktonic state. It is recommended that an adjunctive exogenous photosensitizer be used and that pathogens be exposed to visible light for clinical antimicrobial periodontal therapy.

Purpose: Osteotome sinus floor elevation (OSFE) is an often-used technique of great utility in certain implant patients with resorbed posterior maxilla. Recently benign paroxysmal positional vertigo (BPPV) has been reported as an early postoperative complication following OSFE. Although OSFE-induced BPPV commonly resolves itself within a month without treatment, this complication can be a cause of trouble between the implant surgeon and patient. This report presents a case of BPPV following OSFE. Methods: A 27-year-old man without any significant medical problems and missing his maxillary right first molar, was scheduled for OSFE and simultaneous implant placement. Results: The patient suffered dizziness accompanied by nausea immediately after implant placement using OSFE. Following referral to the ear nose throat clinic, “right posterior canal BPPV” was diagnosed. Despite anti vertigo medication and a single episode of the Epley maneuver, the condition did not improve completely. The Epley maneuver was then applied 7 and 8 days later and the symptoms of BPPV disappeared. One year later, the patient remained symptom-free. Conclusions: Before sinus elevation with an osteotome, implant surgeons should screen out patients with a history of vertigo, to diminish the possibility of BPPV. Operators should be aware of BPPV symptoms. As the symptoms may be very incapacitating, immediate referral to an otorhinolaryngologist is recommended.

A newly emerged periodontopathic pathogen Tannerella forsythia (formerly Bacteroides forsythus), a Gram-negative, filament-shaped, strict anaerobic, non-pigmented oral bacterium, possesses a surface (S-) layer. In our previous studies, the S-layer has been isolated, and shown to mediate hemagglutination, adhesion/invasion of epithelial cell, and murine subcutaneous abscess formation. In the present study, biochemical and molecular genetic characterization of the S-layer are reported. Amino acid sequencing and mass spectrometry indicated that the S-layer is composed of two different proteins, termed 200 and 210 kDa proteins. It was also shown that these proteins are glycosylated. The genes encoding the core proteins of these glycoproteins, designated as tfsA and tfsB, have been identified in silico, cloned, and their sequences have been determined. The tfsA (3.5 kb) and tfsB (4.1 kb) genes are located in tandem, and encode for 135 and 152 kDa proteins, respectively. An apparent discrepancy in molecular weights, 135 vs. 200 kDa and 152 vs. 210 kDa, is accounted for carbohydrate residues attached to the core proteins. Amino acid sequence comparison exhibited a 24% similarity between the 200 and 210 kDa proteins. Further sequence analyses showed that TfsA and TfsB possess putative signal peptide sequences with cleavage sites at alanine residues, and transmembrane domains on the C-terminal region. Northern blot and RT-PCR analyses confirmed an operon structure of tfsAB, suggesting co-regulation of these genes in producing the S-layer. Putative promoter sequences and transcription termination sequences for this operon have also been identified. Comparison with database indicates that the S-layer of T. forsythia has a unique structure exhibiting no homology to other known S-layers of prokaryotic organisms. The present study shows that the T. forsythia S-layer is very unique, since it appears to be composed of two large glycoproteins, and it does not reveal any homology to other known S-layer proteins or glycoproteins of prokaryotic organisms.

Purpose The purpose of this study was to determine the critical diabetes duration in a streptozotocin (STZ)-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration by evaluating the association between diabetes duration and bone healing capacity through histological and radiographic analyses. Methods Experimental diabetes was induced in 50 of 60 rats by an STZ injection. The rats were divided into 5 groups, including a control group (group 1), according to diabetes durations of 0, 2, 4, 6, and 8 weeks, respectively. Eighteen rats survived: 4 in group 1, 4 in group 2, 4 in group 3, 5 in group 4, and 1 in group 5. Calvarial defects were created at 0, 2, 4, 6, and 8 weeks after STZ injection in groups 1–5. Cone-beam computed tomography scanning was performed at baseline and at 5 and 7 weeks after surgery. The rats were sacrificed 7 weeks after surgery, followed by histological evaluation. Results The voxel gray values (VGVs) of group 1 and group 2 increased, whereas the VGVs of group 3 and group 4 decreased starting 5 weeks after surgery, although this trend did not reach statistical significance between groups. On the reconstructed 3-dimensional images and based on an analysis of histological features, groups 1 and 2 showed apparent bone regeneration, while groups 3–5 showed very limited bone regeneration. Conclusions The critical diabetes duration in an STZ-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration was between 2 and 4 weeks. It is suggested that researchers who use STZ-induced diabetic rats wait for more than 2 weeks following diabetes induction before placing implants or conducting bone regeneration studies to allow definite disturbances in bone healing to emerge., Graphical Abstract

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., Graphical Abstract

Purpose The purpose of this retrospective study was to evaluate the effect of patient compliance with supportive periodontal therapy (SPT) on tooth loss in Korean adults. Methods The periodontal records of 134 patients were reviewed for this study. They completed active periodontal treatment from 1999 to 2001 and were placed on a schedule of periodic follow-up visits for SPT. Patient compliance was classified into complete compliance (CC), erratic compliance (EC), and noncompliance (NC) groups. Re-examinations were carried out 11.0±0.8 years after the active periodontal treatment. The prognosis for each tooth was determined as good, questionable, or hopeless according to the bone loss observed in pretreatment radiographs. Results The rate of tooth loss of the CC group was significantly lower than that of the NC group. The tooth loss/patient and the tooth loss/patient/year were not significantly different between the three groups. The rates of tooth loss in the good, questionable, and hopeless prognosis groups were 6.7%, 9.5%, and 13.2%, respectively. For the teeth with a good prognosis, the rate of tooth loss of the CC group was significantly lower than that of the NC group (0.4% vs. 5.1%). For the teeth with a questionable prognosis, the CC group showed a significantly lower rate of tooth loss than did the EC group (4.1% vs. 30.7%) or the NC group (4.1% vs. 25.6%). For the teeth with a hopeless prognosis, the rates of tooth loss were not significantly different among the three groups. Conclusions Within the limits of this study, the patients who showed a poor compliance with SPT were more likely to lose teeth than were the regularly compliant patients. However, the risk of tooth loss with a hopeless prognosis was high irrespective of the compliance. Graphical Abstract

Purpose: The aim of this study was to obtain objective and standardized information on masticatory function and patient satisfaction following second molar single implant therapy. Methods: Twenty adult patients, who had restored second molar single implants more than 1 month before the study, were enrolled in this study. All patients received a chewing test using peanuts before and after insertion of the implant prosthesis, with a questionnaire and visual analogue scale (VAS) to evaluate the effect of second molar single implant therapy. Results: This study obtained standardized information on the masticatory function objectively (e.g., P, R, X50) before (Pre-insertion) and after insertion (Post-insertion) of the implant prosthesis. Masticatory performance (P) after insertion of the implant prosthesis significantly increased from 67.8 ± 9.9 to 84.3 ± 8.5% (P < 0.0001). With the implant prosthesis, the P value increased by 24%. The masticatory efficiency index (R) of Post-insertion is higher than that of Pre-insertion (P < 0.0001). With the implant prosthesis, the R value increased by 29%. The median particle size (X50) of Post-insertion is lower than that of Preinsertion (P < 0.0001). More than 90% of the patients were satisfied with the second molar single implant therapy from a functional point of view. Conclusions: These findings indicate that a second molar single implant can increase masticatory function.

Purpose: The purpose of this study was to radiographically evaluate marginal bony changes in relation to different vertical positions of dental implants. Methods: Two hundred implants placed in 107 patients were examined. The implants were classified by the vertical positions of the fixture-abutment connection (microgap): ‘bone level,’ ‘above bone level,’ or ‘below bone level.’ Marginal bone levels were examined in the radiographs taken immediately after fixture insertion, immediately after second-stage surgery, 6 months after prosthesis insertion, and 1 year after prosthesis insertion. Radiographic evaluation was carried out by measuring the distance between the microgap and the most coronal bone-to-implant contact (BIC). Results: Immediately after fixture insertion, the distance between the microgap and most coronal BIC was 0.06 ± 0.68 mm; at second surgery, 0.43 ± 0.83 mm; 6 months after loading, 1.36 ± 0.56 mm; and 1 year after loading, 1.53 ± 0.51 mm (mean ± SD). All bony changes were statistically significant but the difference between the second surgery and the 6-month loading was greater than between other periods. In the ‘below bone level’ group, the marginal bony change between fixture insertion and 1 year after loading was about 2.25 mm, and in the ‘bone level’ group, 1.47 mm, and in ‘above bone level’ group, 0.89 mm. Therefore, the marginal bony change was smaller than other groups in the ‘above bone level’ group and larger than other groups in the ‘below bone level’ group. Conclusions: Our results demonstrated that marginal bony changes occur during the early phase of healing after implant placement. These changes are dependent on the vertical positions of implants.

Purpose The purpose of this study was to evaluate the effects of implant shape and bone preparation on the primary stability of the implants using resonance frequency analysis. Methods Sixty bovine rib blocks were used for soft and hard bone models. Each rib block received two types of dental implant fixtures; a straight-screw type and tapered-screw type. Final drilling was done at three different depths for each implant type; 1 mm under-preparation, standard preparation, and 1 mm over-preparation. Immediately after fixture insertion, the implant stability quotient (ISQ) was measured for each implant. Results Regardless of the bone type, the ISQ values of the straight-screw type and tapered-screw type implants were not significantly different (P > 0.05). Depth of bone preparation had no significant effect on the ISQ value of straight-screw type implants (P > 0.05). For the tapered-screw type implants, under-preparation significantly increased the ISQ value (P < 0.05), whereas overpreparation significantly decreased the ISQ value (P < 0.05). Conclusions Within the limitations of this study, it is concluded that bone density seemed to have a prevailing effect over implant shape on primary stability. The primary stability of the tapered-screw type implants might be enhanced by delicate surgical techniques.

The present study investigated the effects of surface chemistry and topography on the strength and rate of osseointegration of titanium implants in bone. Three groups of implants were compared: (1) machine-turned implants (turned implants), (2) machine-turned and aluminum oxide-blasted implants (blasted implants), and (3) implants that were machine-turned, aluminum oxide-blasted, and processed with the micro-arc oxidation method (Mg implants). Three and six weeks after implant insertion in rabbit tibiae, the implant osseointegration strength and rate were evaluated. Surface chemistry revealed characteristic differences of nine at.% Mg for Mg implants and 11 at.% Al for blasted implants. In terms of surface roughness, there was no difference between Mg implants and blasted implants in developed surface ratio (Sdr; p = 0.69) or summit density (Sds; p = 0.96), but Mg implants had a significantly lower arithmetic average height deviation (Sa) value than blasted implants (p = 0.007). At both 3 and 6 weeks, Mg implants demonstrated significantly higher osseointegration strength compared with turned (p = 0.0001, p = 0.0001) and blasted (p = 0.0001, p = 0.035) implants, whereas blasted implants showed significantly higher osseointegration than turned implants at 6 weeks (p = 0.02) but not at 3 weeks (p = 0.199). The present results not only support the hypothesis that biochemical bonding facilitates rapid and strong integration of implants in bone, but also provide evidence for biochemical bonding theory previously proposed by Sul.

Innate elastase inhibitors are known to be putatively involved in the regulation of tissue inflammation by inhibiting polymorphonuclear leukocyte (PMN) derived proteinases. The aim of this study was to evaluate affects of leukocyte elastase suppression and PMN infiltration on wound healing in mouse by administering the recombinant elastase inhibitor guamerin (rEIG) in two different wound models; 1) impaired pin-punctured dorsal mucosa of anterior tongue wound, 60 mice, treated with saline containing rEIG that were fed ad libitum and 2) stable linear excisional cutaneous wound, 40 mice, covered with fibrin sealant containing rEIG. The progress of healing was analyzed by histological methods. The tongue wounds treated with rEIG became edematous around the pin-punctured tongue wound, and influx of inflammatory cells and PMN into the underlying stromal tissue were seen rapidly after wounding and peaked between 2-4 days. Whereas the control mice showed almost no wheal formation in the pin-punctured wound, a far lesser levels of PMN infiltration, and almost complete wound closure in 4 days. In the other model, the liner excisional cutaneous wound treated with fibrin sealant containing rEIG showed early wound constriction, lesser degree of inflammatory cells influx, and complete reepithelialization in 4-5 days, whereas the wound of control mice with the fibrin sealant alone showed contrary delayed reepithelialization, greater degree of inflammatory cell infiltration, and consequencial formation of greater granulation tissue at wound site. Taken together, these data suggest paradoxical effects of rEIG on the wound healing where in the wound exposed to infiltrating milieu of microorganisms in the oral cavity, the rEIG aggravates the wound healing by interfering with other innate defensive factors and extended greater flux of PMNs to inflamed wound site, while in the wound enclosed by fibrin, the rEIG accelerated wound healing by inhibiting the inflammation-generated proteases and the acute inflammatory reaction.

Purpose: The aim of this study is to assess the influence exerted by the observer’s dental specialization and compare patients’ opinion with observers’ opinion of the esthetics of maxillary single-tooth implants in the esthetic zone. Methods: Forty-one adult patients, who were treated with a single implant in the esthetic zone, were enrolled in this study. Eight observers (2 periodontists, 2 prosthodontists, 2 orthodontists and 2 senior dental students) applied the pink esthetic score (PES)/white esthetic score (WES) to 41 implant-supported single restorations twice with an interval of 4 weeks. We used a visual analog scale (VAS) to assess the patient’s satisfaction with the treatment outcome from an esthetic point of view. Results: In the PES/WES, very good and moderate intraobserver agreements were noted between the first and second rating. The mean total PES/WES was 11.19 ± 3.59. The mean PES was 5.17 ± 2.29 and mean WES was 6.02 ± 1.96. In the total PES/WES, the difference between the groups was not significant. However, in the WES, the difference between the groups was significant and prosthodontists were found to have assigned poorer ratings than the other groups. Periodontists gave higher ratings than prosthodontists and senior dental students. Orthodontists were clearly more critical than the other observers. The statistical analysis revealed statistically significant correlation between patients’ esthetic perception and dentists’ perception of the anterior tooth. However, the correlation between the total PES/WES and the VAS score for the first premolar was not statistically significant. Conclusions: The PES/WES is an objective tool in rating the esthetics of implant supported single crowns and adjacent soft tissues. Orthodontists were the most critical observers, while periodontists were more generous than other observers. The statistical analysis revealed a statistically significant correlation between patients’ esthetic perception and dentists’ perception of the anterior tooth.

Purpose: Tetracycline and its chemically modified non-antibacterial analogues can inhibit certain host-derived tissue destructive collagenases such as matrix metalloproteinases. The purpose of this study was to evaluate clinical and microbiologic effects of the subantimicrobial dose of doxycycline(SDD) in conjunction with scaling and root planing. Materials and methods: A total of 30 patients with chronic periodontitis who were going to receive scaling and root planing were randomly allocated to receive either a doxycycline hyclate for 3 months or nothing. Clinical probing depth, clinical attachment level, gingival recession, and bleeding on probing were measured by one periodontist. After a periodontal examination, microbial samples were collected using sterile paper points. The effect of SDD in conjunction with scaling and root planing on alterations of the periodontal pathogens (Aggregatibacter actinomycetemcomitans, Tannerella forsythia, Porphyromonas gingivalis) were also assessed using 16S rRNA polymerase chain reaction. Results: During the treatment period, clinical parameters for both treatment group and control group were improved. After 3 months, reductions in probing depth and gains in clinical attachment level were significantly greater for the SDD group than control group. Microbial analysis showed that there was no alteration of the periodontal pathogens and no difference between the groups. Conclusion: This study suggested that the subantimicrobial dose of doxycycline as an adjunct therapy with scaling and root planing might be effective and safe in the management of chronic periodontitis. (J Korean Acad Periodontol 2009;39:37-44)

Purpose: It is well recognized that gingival enlargement is induced by unwanted effect associated with three major drugs/drug groups - phenytoin, cyclosporine, and the calcium channel blockers. The present case report describes the effect and limitation of non-surgical treatment in gingival enlargement cases. Materials and methods: Three cases included 2 drug-influenced gingival enlargement patients and a idiopathic gingival fibromatosis patient. For the drug-influenced gingival enlargement patients, the medication was replaced with other medication. And then, all the patients were treated non-surgically. Results: Drug-influenced gingival enlargements had been reduced after non-surgical treatment and the results were well-maintained. In the idiopathic gingival fibromatosis case, non-surgical treatment resulted in only limited reduction of gingival enlargement, and surgical periodontal treatment was unavoidable. Conclusion: These case reports indicated that non-surgical periodontal treatment with change in medication was effective in the treatment of drug-influenced gingival enlargements. Non-surgical approach can be considered as the primary management to reduce the gingival enlargement. If non-surgical treatment encounters a limitation, surgical treatment should be considered. (J Korean Acad Periodontol 2009;39:103-108)

Background: Incomplete flap coverage or early exposure over implants and/or barrier membranes have a negative effect on bone regeneration. In cases of using regenerative techniques, complete soft tissue coverage of the implant area is necessary to promote adequate conditions for guided bone regeneration. Primary socket closure may be difficult, when periosteal releasing incision is only used, due to the opening left by extracted tooth. Therefore, Soft tissue grafting techniques are used to achieve primary soft tissue closure. Materials and Methods: Soft tissue grafting techniques, with or without barrier membranes, were performed for primary closure in four cases of immediate placements. Three different methods were used (CTG, VIP-CT, Palatal advanced flap). Clinical results of the grafting were evaluated. Result: One case showed early exposure of cover-screw and, no other complications were noted. In the others, Primary closure was achieved by soft tissue grafting techniques. One of the cases, Graft showed partial necrosis, but there were no exposure over implants and/or barrier membranes. Conclusion: The use of grafting techniques, in immediate implant placement, can predictably obtain primary closure of extraction sockets, thereby providing predictable bone formation and improved implant results. (J Korean Acad Periodontol 2008;38:253-262)

Purpose: The purpose of this study was to investigate the incidence of curet fracture and its contributing factors. Material and Methods: Fifty-eight periodontal curets which were broken during periodontal treatment in Kangnung National University Dental Hospital for 1 year were used as study materials. The blade thickness of new curets and broken ones was measured using a digital micrometer. Types of treatment procedures, clinical experience of operators, point of breakage, and method of removal of broken fragments were recorded for each broken curet. Results: The incidence of curet fracture in root planing (16.4 curets per 1,000 procedures) was higher than those in flap surgery (7.5) or supragingival scaling (2.7). No curet was broken during supportive periodontal treatment. The incidence of fracture did not seem to be related with clinical experience of operators. The most frequent breakage point of the curets were upper 1/3 of blades. Fifty-six of 58 broken fragments were removed by non-surgical methods. Two broken tips which could not removed non-surgically were left in the pockets, and proved to be removed spontaneously 1 week later. Conclusion: Root planing showed higher incidence of curet fracture than any other type of periodontal treatment. Most of the fractured fragments were removed by non-surgical method. Further study is needed to develop methods of removal of the fragments which can not be removed non-surgically. (J Korean Acad Periodontol 2008;38:23-30)

Amlodipine, nifedipine, and felodipine are calcium channel blocking agents, which are cause of unwanted gingival overgrowth around natural teeth. Many studies has been performed about this unwanted effects. However, the exact etiology remains uncertain.Few reports and investigations can be found in ...

1 Internal Medicine and 2 Laboratory Medicine, Sanggyepaik Hospital, Inje University College of Medicine, Seoul, Korea Thalidomide is an anti-angiogenic agent widely used in patients with multiple myeloma. The response to therapy is commonly monitored using serum and/or urine M protein, as these are known to reflect the tumor burden. Although extramedullary plasmacytomas are tissues with high neovascularization, it has been suggested in some reports that the response to thalidomide in these patients may be inferior, despite changes in the serum M protein level. Herein, we report the case of a patient who newly developed hepatosplenic extramedullary plasmacytoma, despite reduction in the serum M protein level following thalidomide treatment. (Korean J Hematol 2005;40:188-191.)