Antimicrobial effect of toothbrush with light emitting diode on dental biofilm attached to zirconia surface: an in vitro study

PURPOSE: The purpose of this study was to evaluate the antimicrobial effects of a toothbrush with light-emitting diodes (LEDs) on periodontitis-associated dental biofilm attached to a zirconia surface by static and dynamic methods. MATERIALS AND METHODS: Zirconia disks (12 mm diameter, 2.5 mm thickness) were inserted into a 24-well plate (static method) or inside a Center for Disease Control and Prevention (CDC) biofilm reactor (dynamic method) to form dental biofilms using Streptococcus gordonii and Fusobacterium nucleatum. The disks with biofilm were subdivided into five treatment groups-control, commercial photodynamic therapy (PDT), toothbrush alone (B), brush with LED (BL), and brush with LED+erythrosine (BLE). After treatment, the disks were agitated to detach the bacteria, and the resulting solutions were spread directly on selective agar. The number of viable bacteria and percentage of bacterial reduction were determined from colony counts. Scanning electron microscopy (SEM) was performed to visualize alterations in bacterial morphology. RESULTS: No significant difference in biofilm formation was observed between dynamic and static methods. A significant difference was observed in the number of viable bacteria between the control and all experimental groups (P < 0.05). The percentage of bacterial reduction in the BLE group was significantly higher than in the other treated groups (P < 0.05). SEM revealed damaged bacterial cell walls in the PDT, BL, and BLE groups, but intact cell walls in the control and B groups. CONCLUSION: The findings suggest that an LED toothbrush with erythrosine is more effective than other treatments in reducing the viability of periodontitis-associated bacteria attached to zirconia in vitro.

Determination of the optimal diabetes duration for bone regeneration experiments in an alloxan-induced diabetic rabbit calvarial defect model

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.

Efficacy of an LED toothbrush on a Porphyromonas gingivalis biofilm on a sandblasted and acid-etched titanium surface: an in vitro study

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 < 0.05). Scanning electron microscopy showed that bacterial cell walls were intact in the control and B groups, but changed after commercial PDT and LED exposure. CONCLUSIONS: The findings suggest that an LED toothbrush with erythrosine treatment was more effective than a commercial PDT kit in reducing the number of P. gingivalis cells attached to surface-modified titanium in vitro.

Comparison of periodontitis-associated oral biofilm formation under dynamic and static conditions

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.

Determination of the critical diabetes duration in a streptozotocin-induced diabetic rat calvarial defect model for experimentation regarding bone regeneration

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.

Effect of fluoride-containing gel on the roughness of a titanium surface and the promotion of bacterial growth

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.

Factors associated with the survival and marginal bone loss of dental implants: a 5-year retrospective study

PURPOSE: The purpose of this study was to compare the long-term survival rate and peri-implant marginal bone loss related to multiple risk factors including the clinician's experience. MATERIALS AND METHODS: Four hundred twenty implants in 146 patients, who had involved a supportive periodontal therapy program every 3 to 6 months and had follow up data for at least 5 years, were selected as the study group. Peri-implant marginal bone loss, data of demographic, implant and surgical characteristics were collected from peri-apical radiographs and chart review. Implant survival was regarded as the remaining with radiographic marginal bone level in excess of 50% of the fixture length for any reason. RESULTS: The cumulative survival rate after 5 years of loading was 94.9%. In binary logistic regression analysis, smoking status (P = 0.033) and presence of spontaneous cover screw exposure (P < 0.001) were significantly related to 5-year survival of implants. In stepwise multiple regression analysis, smoking status (P < 0.001), type of abutment connection (P < 0.001) and implant surface (P = 0.033) were significantly related to peri-implant marginal bone level. And the year of resident was not statistically related to 5-year implant survival in simple logistic regression analysis (P = 0.171). CONCLUSION: Smoking status, spontaneous cover screw exposure, type of abutment connection and implant surface might influence the implant success. There was no significant correlation between the year of resident and implant failure.

The effect of photodynamic therapy on Aggregatibacter actinomycetemcomitans attached to surface-modified titanium

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 microL of 20 microM 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 37degrees C, 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<0.05). A significantly lower quantity of CFU/mL was found in the E30 and E60 groups on both titanium disk surfaces. In confocal scanning laser microscopy images, increased bacterial death was observed when disks were irradiated for a longer period of time. CONCLUSIONS: These findings suggest that PDT using erythrosine and a green LED is effective in reducing the viability of A. actinomycetemcomitans attached to surface-modified titanium in vitro.

Effect of supportive periodontal therapy on the prevention of tooth loss in Korean adults

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.

A periodontitis-associated multispecies model of an oral biofilm

PURPOSE: While single-species biofilms have been studied extensively, we know notably little regarding multispecies biofilms and their interactions. The purpose of this study was to develop and evaluate an in vitro multispecies dental biofilm model that aimed to mimic the environment of chronic periodontitis. METHODS: Streptococcus gordonii KN1, Fusobacterium nucleatum ATCC23726, Aggregatibacter actinomycetemcomitans ATCC33384, and Porphyromonas gingivalis ATCC33277 were used for this experiment. The biofilms were grown on 12-well plates with a round glass slip (12 mm in diameter) with a supply of fresh medium. Four different single-species biofilms and multispecies biofilms with the four bacterial strains listed above were prepared. The biofilms were examined with a confocal laser scanning microscope (CLSM) and scanning electron microscopy (SEM). The minimum inhibitory concentrations (MIC) for four different planktonic single-species and multispecies bacteria were determined. The MICs of doxycycline and chlorhexidine for four different single-species biofilms and a multispecies biofilm were also determined. RESULTS: The CLSM and SEM examination revealed that the growth pattern of the multispecies biofilm was similar to those of single-species biofilms. However, the multispecies biofilm became thicker than the single-species biofilms, and networks between bacteria were formed. The MICs of doxycycline and chlorhexidine were higher in the biofilm state than in the planktonic bacteria. The MIC of doxycycline for the multispecies biofilm was higher than were those for the single-species biofilms of P. gingivalis, F. nucleatum, or A. actinomycetemcomitans. The MIC of chlorhexidine for the multispecies biofilm was higher than were those for the single-species biofilms of P. gingivalis or F. nucleatum. CONCLUSIONS: To mimic the natural dental biofilm, a multispecies biofilm composed of four bacterial species was grown. The 24-hour multispecies biofilm may be useful as a laboratory dental biofilm model system.

Phototoxic effect of blue light on the planktonic and biofilm state of anaerobic periodontal pathogens

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/cm2 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 microm. 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.

The Effect of Erythrosine-mediated Photodynamic Therapy on Intraorally Formed Biofilm on Titanium Surface

The purpose of this study was to assess the efficacy of photodynamic therapy (PDT) using erythrosine and a halogen light source to treat a biofilm formed on a machined surface titanium disk in vivo. Ten volunteers carried an acrylic appliance containing six machined surface titanium disks on the upper jaw over a period of five days. After the five days of biofilm formation period, the disks were removed. PDT using 20 microM erythrosine and halogen light was then applied to the biofilms formed on the disks. Experimental samples were divided into a negative control group (no erythrosine and no irradiation), E0 group (erythrosine 60s + no irradiation), E30 group (erythrosine 60s + halogen light 30s), and E60 group (erythrosine 60s + halogen light 60s). Following PDT, the bacteria in the biofilm were found to be detached from each disk. Each suspension with detached bacteria were diluted and cultivated on a blood-agar plate for five days under anaerobic conditions. The cultivated bacterial counts in the E60 group were significantly lower than the control group (86.4%) or E0 group (76.7%). In the experimental groups also, the light exposure time and bacterial counts showed a negative correlation. In conclusion, PDT using erythrosine and halogen light has bactericidal effects on biofilms formed on a titanium disk in vivo. Notably, applying 20 microM erythrosine and 60 seconds of halogen light irradiation had a significantly potent effect.

Comparison of photodynamic bactericidal effects of erythrosine against Streptococcus mutans and Streptococcus sobrinus by different wavelength of LED lights / 대한구강보건학회지

No abstract available.

Masticatory function following implants replacing a second molar

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 Pre-insertion (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.

Benign paroxysmal positional vertigo as a complication of sinus floor elevation

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.

Esthetic evaluation of maxillary single-tooth implants in the esthetic zone

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.

The effect of implant shape and bone preparation on primary stability

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.

Marginal bony changes in relation to different vertical positions of dental implants

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.

Clinical and microbiologic effects of the subantimicrobial dose of doxycycline on the chronic periodontitis / 대한치주과학회지

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.

A retrospective study on patients' compliance with supportive periodontal therapy / 대한치주과학회지

PURPOSE: The purpose of this study was to investigate the degree of compliance with supportive periodontal therapy(SPT), to determine if any significant differences existed in the characteristics of compliant, erratically compliant and non-compliant patients and to identify reasons for poor compliance. MATERIALS AND METHODS: Four hundred five patients who initially visited between July 2003 and December 2004 and were treated until June 2005 were retrospectively evaluated for their compliance with SPT in terms of attendance for a recommended schedule of visits. Patients' compliance was classified as complete compliance(attended more than 80% of the recommended appointments), erratic compliance(attended less than 80% of the recommended appointments or discontinued) and non-compliance(did not return for SPT). Analysis was made for each group to correlate the degree of compliance with gender, age, smoking, distance between their houses and the hospital, disease severity, type of therapy, implant, plaque control instruction and systemic diseases. Tele research of erratically compliant and non-compliant patients was carried out to identify reasons for their poor compliance. RESULTS: Only 24.7% of the patients were in complete compliance. The highest drop-out rate(32.4%) occurred in the first year. A significantly greater percentage of non-smokers and patients who finished plaque control instruction were in complete compliance. A significantly greater percentage of patients without implant and patients who had been treated by only scaling and root planing were in non-compliance. More males were found to be compliant with SPT, although this was marginally significant. There were no significant differences between compliant, erratically compliant and non-compliant patients with regard to age, distance, disease severity and systemic disease. The survey revealed that the main reasons for poor compliance with SPT were inconvenient location and insufficient time. CONCLUSION: Patients' compliance with SPT was poor and the highest drop-out rate(32.4%) occurred in the first year. Significant relationships were found between the degree of compliance and smoking, type of therapy, implant, plaque control instruction and gender.