Bone cement grafting increases implant primary stability in circumferential cortical bone defects

PURPOSE: Implant beds with an insufficient amount of cortical bone or a loss of cortical bone can result in the initial instability of a dental implant. Thus, the objective of this study was to evaluate the effect of bone cement grafting on implant initial stability in areas with insufficient cortical bone. METHODS: Two different circumferential defect depths (2.5 mm and 5 mm) and a control (no defect) were prepared in six bovine rib bones. Fourteen implants of the same type and size (4 mm x 10 mm) were placed in each group. The thickness of the cortical bone was measured for each defect. After the implant stability quotient (ISQ) values were measured three times in four different directions, bone cement was grafted to increase the primary stability of the otherwise unstable implant. After grafting, the ISQ values were measured again. RESULTS: As defect depth increased, the ISQ value decreased. In the controls, the ISQ value was 85.45+/-3.36 (mean+/-standard deviation). In circumferential 2.5-mm and 5-mm defect groups, the ISQ values were 69.42+/-7.06 and 57.43+/-6.87, respectively, before grafting. These three values were significantly different (P<0.001). After grafting the bone cement, the ISQ values significantly increased to 73.72+/-8.00 and 67.88+/-10.09 in the 2.5-mm and 5.0-mm defect groups, respectively (P<0.05 and P<0.001). The ISQ value increased to more than double that before grafting in the circumferential 5-mm defect group. The ISQ values did not significantly differ when measured in any of the four directions. CONCLUSIONS: The use of bone cement remarkably increased the stability of the implant that otherwise had an insufficient level of stability at placement, which was caused by insufficient cortical bone volume.

Location of maxillary intraosseous vascular anastomosis based on the tooth position and height of the residual alveolar bone: computed tomographic analysis

PURPOSE: The aims of this study were to measure the distance of the intraosseous vascular anastomosis in the anterolateral wall of the maxillary sinus from different reference points, and to correlate the location of the intraosseous vascular anastomosis with the tooth position and the residual bone height of the maxilla. METHODS: Computed tomography (CT) images were taken from 283 patients undergoing dental implants placement in the posterior maxilla. Three horizontal lines were drawn at the ridge crest, maxillary sinus floor, and the position of the anastomosis. A vertical second line at the center of each tooth was drawn perpendicular to the horizontal lines. The distance from the ridge crest to the maxillary sinus floor and the distance from the maxillary sinus floor to the bony canal were measured from the intersections of the horizontal and vertical lines. The residual alveolar bone height was used to categorize three groups: group 1,8 mm. RESULTS: The residual bone height values of different tooth positions were significantly different (P=0.0002). The distance from the maxillary sinus floor to the intraosseous vascular anastomosis was significantly different between groups 1 and 3 (P=0.0039). At the molar sites, a moderate negative correlation was found between the residual bone height and the distance from the maxillary sinus floor to the intraosseous anastomosis. The distances of the alveolar ridge crest and the maxillary sinus from the intraosseous vascular anastomosis were not significantly different between sexes. CONCLUSIONS: Within the limitations of this study, sites with a higher residual bone height in the molar regions were at a relatively high risk of artery damage during window osteotomy preparation; therefore, we recommend taking more precautions when using a lateral approach for sinus elevation.

The effect of non-resorbable barrier membrane on the change of buccal and lingual alveolar bone in immediate implant placement into periapically infected extraction sockets / 대한치주과학회지

PURPOSE: Many researches showed loss of alveolar bone in fresh extraction socket and even in case of immediate implant placement. The aim of this study was to evaluate the effect of non-resorbable barrier membrane on the change of buccal and lingual alveolar bone in immediate implant placement into periapically infected extraction sockets. MATERIALS AND METHODS: Immediate implants were placed into artificially induced periapical lesion of mandibular premolars after complete debridement using buccal bone defect made by a 6mm trephine bur in 4 mongrel dogs. Before flap repositioning, a non-resorbable barrier membrane was placed on the buccal defect in the experimental group. No membrane was placed in the control group. In 12 weeks after placement, the dogs were sacrificed and undecalcified histologic specimens were prepared. The vertical distance from the smooth-rough surface interface(SRI) to gingiva, 1st bone contact and bone crest were measured in buccal and lingual side. The horizontal thicknesses of gingiva and bone at 0, 1, 2 and 3 mm below SRI were measured. RESULTS: The buccal bone was resorbed more than lingual bone in both groups and there was statistical significance(p<0.05). The distances from SRI to 1st bone contact were 2.45+/-2.35 mm in experimental group and 4.49+/-3.10 mm in control group. In all vertical level, lingual bone was thicker than buccal bone(p<0.05). CONCLUSION: Buccal bone was reduced more than lingual bone in immediate implant placement into periapically infected extraction sockets. Placement of non-resorbable barrier membrane reduced the buccal bone resorption. However there was no statistical significance.

Maxillary sinus floor augmentation with anorganic bovine bone: Histologic evaluation in humans / 대한치주과학회지

PURPOSE: The aim of this report is to investigate the efficacy of anorganic bovine bone xenograft(Bio-Oss(R) ) at maxillary sinus floor augmentation. MATERIALS AND METHODS: Two male patients who missed maxillary posterior teeth were included. They were performed maxillary sinus floor augmentation using anorganic bovine bone xenograft(Bio-Oss(R) ). After 10 or 13 months, the regenerated tissues were harvested using trephine drills with 2 or 4mm diameter and non-decalcified specimens were made. The specimens were examined histologically and histomorphometrically to investigate graft resorption and new bone formation. RESULTS: Newly formed bone was in contact with Bio-Oss(R) particles directly without any gap between the bone and the particles. The proportions of newly formed bone were 23.4~25.3% in patient 1(Pt.1) and 28.8% in patient 2(Pt.2). And the proportions of remained Bio-Oss(R) were 29.7~30.2% in Pt.1 and 29.2% in Pt.2. The fixtures installed at augmented area showed good stability and the augmented bone height was maintained well. CONCLUSION: Anorganic bovine bone xenograft(Bio-Oss(R) ) has high osteoconductivity and helps new bone formation, so that it can be used in maxillary sinus floor augmentation.

The effect of chlorhexidine on reduction of viable organisms in aerosol produced by ultrasonic scaler / 대한치주과학회지

PURPOSE: The aerosol generated by ultrasonic scaler can contain bacteria or virus which can penetrate into body through respiratory systems of dentists, dental hygienist or patients. The aim of this study is to evaluate the effect of chlorhexidine digluconate as preoperative mouthrinse or lavage for ultrasonic scaler on the reduction of viable organisms in aerosol produced during periodontal treatment using ultrasonic scaler. METHODS: 30 patients with moderate chronic periodontitis were included and divided into 3 groups: Control (no preoperative mouthrinse and tap water as lavage), CHG (preoperative mouthrinse with 0.1% chlorhexidine digluconate and tap water as lavage), CHL (no reoperative mouthrinse and 0.1% chlorhexidine digluconate as lavage). Each patient received scaling or subgingival curettage for 30 min. In CHG group, mouthrinse with chlorhexidine digluconate was performed for 1 min. before treatment. Before, during and after scaling or subgingival curettage, air sampling was performed for 7 min. each (1000 L/7 min.) with trypticase-soy agar plate. Agar plates were incubated in 37degrees C aerobically. The numbers of colony-forming units (CFU) were counted and compared. RESULTS: The numbers of CFUs of the samples obtained during treatment were 97+/-14.0 in control, 73.1+/-14.9 in CHG group and 44.5+/-9.0 in CHL group. The difference among the 3 groups was determined to be statistically significant (one-way ANOVA with Bonferroni's correction, p-value: 0.0003). In contrast, the numbers of CFU of samples obtained before and after treatment were not significantly different among the groups. CONCLUSIONS: Chlorhexidine digluconate used as preoperative mouthrinse or lavage for ultrasonic scaler can reduce the microorganisms in aerosol produced during periodontal treatment using ultrasonic scaler. Less number of microorganisms were detected when chlorhexidine was used as lavage for ultrasonic scaler.

The effect of implant drilling speed on the composition of particle collected during site preparation / 대한치주과학회지

PURPOSE: This study was aimed to evaluate the effect of implant drilling speed on the composition of particle size of collected bone debris. METHODS: Branemark System (R)drills were used to collect bone debris from 10 drilling holes (1 unit) at 1,500 rpm (Group A) and 800 rpm (Group B) in bovine mandible. After separating particles by size into > 500 microm, between 250 microm and 500 microm, and 500 microm fractions, Group B had significantly higher wet volume % (P = 0.0059) and dry volume % (P = 0.0272) than in Group A. CONCLUSIONS: The drilling speed influenced the composition of particle size in collected drilling bone debris. The drilling in 800 rpm produced the more percentage of large particles than in 1,500 rpm. However, the drilling speed didn't effect on total volume of and weight of bone debris.

Fluorescent detection of bacteria associated with gingival sulcus epithelium / 대한치주과학회지

PURPOSE: The aim of this study was to compare the number of live and dead bacteria attached to, or within, the stratified squamous epithelium lining the tissue side of the gingival sulcus. MATERIALS AND METHODS: A total of 50 patients was examined and classified into healthy or diseased sites according to inflammatory status of the gingival tissue. The surface of stratified squamous epithelium was removed by gentle scraping of the gingival sulcus with curettes. The cells were processed in the laboratory by density-gradient centrifugation to separate the epithelial cells from the loose bacteria and debris. The LIVE/DEAD(R) BacLight(TM) Bacterial Viability Kit was applied and the specimens were observed by an epifluorescent microscope and the number of bacteria was counted. RESULTS: Live and dead bacteria were stained to green and red, irrespectively. Generally, the number of total bacteria in the diseased sites was significantly higher than in the healthy sites. The mean number of detected bacteria in the diseased sites was 58.6+/-36.0 (red bacteria 10.4+/-9.2 / green bacteria 48.2+/-30.5), while it was 1.5+/-1.7 in the healthy sites (red bacteria 0.1+/-0.3 / green bacteria 1.4+/-1.5). The percentage of red bacteria was 17.5+/-11.2% in the diseased sites and 2.0+/-5.8% in the healthy sites. CONCLUSION: The total number of bacteria in the diseased sites was significantly higher than that of the healthy sites. The ratio and the number of red bacteria were also significantly higher in the diseased sites.

Effect of resorbable membrane on immediate placement of implant in extraction socket during periradicular surgery / 대한치주과학회지

PURPOSE: The guided bone regeneration (GBR) technique is widely used in periradicular surgery. However, there is still some controversy regarding the effectiveness of GBR in promoting bone healing after periradicular surgery. The purpose of this study was to evaluate the resorbable membrane on the osteointegration of immediate implants in sites with periradicular lesion that had been removed by periradicular surgery. MATERIALS AND METHODS: Six roots of lower second premolars and 15 roots of lower third and fourth premolars of dogs were used as control and experimental teeth, respectively. Periradicular lesions were induced only in the experimental teeth. Twelve weeks later, the control and experimental teeth were extracted and implants were placed immediately. Periradicular lesions were removed with osteotomy, curettage and saline irrigation. Resorbable membranes were used in experimental group 1 but not in experimental group 2. After 12 week of healing period, the implants were clinically not mobile and showed no signs of infection. Data obtained by histomorphometric analysis were analyzed by Kruskal-Wallis test. RESULTS: The control group showed a significantly higher bone to implant contact (BIC) (74.14+/-16.18) than experimental group 1 (40.28+/-15.96) and 2 (48.70+/-17.75)(p<0.05). However, there was no significant difference between experimental group 1 and 2. CONCLUSION: Although BIC in experimental groups were lower than in control group, immediate implant can be successfully placed at extraction socket with periradicular lesion and osseous defect. However, the use of resorbable membrane in bony defect created during periradicular surgery was questioned.

A 3 year-retrospective study of survival rate in single Branemark TiUnite(TM) implant / 대한치주과학회지

BACKGROUND: TiUnite(TM) is a highly crystalline and phosphate enriched titanium oxide surface which has a unique porous surface structure. This improved implant surface enhances bone response and reduces healing period. It also assures early stability of implant. These help to increase the success of implant. The aim o f this s tudy i s to e valuate the survival r ate of TiUnite TM surfaced single implant. MATERIALS AND METHODS: A retrospective analysis of 89 TiUnite(TM) surfaced implants replacing a single tooth was assessed according to their dental record. The age of the patients ranged from 17 to 82 years (mean age: 45.8 +/- 14.6). Data were recorded regarding the survival rate of these implants. RESULTS: Fifty-two implants (57%) were placed in the maxilla, and 37 (43%) in the mandible. Over 75% were placed in the posterior area. Of the placed implants, 67% were the wide type, while 25% were the regular type and only 8% were of the narrow type. The single implants produced an overall clinical survival rate of 96.6% over the observation period (mean 17.9 months). Among 89 implants, only 2 implants were removed and one implant was submerged. CONCLUSION: According to t he se data, TiUnite(TM) surfaced implant in a single tooth restoration showed favorable survival rate although this study was done in a short term period.

Effect of cleansing me thods on the bone re sorption due to repeated dis/re-connection of implant abutment / 대한치주과학회지

BACKGROUND: Repeated dis/re-connection of implant abutment caused bone loss around implant fixtures due to the new formation of biologic width of the mucosal-implant barrier. The aim of this clinical study was to evaluate whether the repeated dis/re-connection of implant abutment cause bone loss clinically and the effect of cleansing methods on a bone loss during the early healing period. METHODS: A total 50 implants were installed in 20 patients and repeated dis/re-connection of abutment was performed at the time of surgery and once per week for 12 weeks. 0.9% normal saline solution as group1 and 0.1% chlorhexidine solution as group 2 was used to clean abutments. All patients had radiographs taken at the placement of implant and 4, 8, and 12 weeks postoperatively. The data for bone loss around implant were analyzed. RESULTS: The marginal bone loss at 12 weeks were 1.28+/-0.51mm, 1.32+/-0.57mm in the mesial and distal sides in group1, 1.94+/-0.75mm, 1.81+/-0.84mm in group 2, respectively. In view of marginal bone loss, there was not a significant statistical difference between groups. CONCLUSIONS: Repeated dis/re-connection of implant abutment may not cause marginal bone loss around implant fixture although limited samples and short-term observation period. In spite of more bone loss in group 2, there was no statistical significant difference between groups. In context of those results, the clinical significance of the repeated dis/re-connection of implant abutment and the cleansing method of abutments is debatable when it comes to marginal bone loss during early healing period.

Histologic evaluation of Regenafil(TM) on defects of extraction socket / 대한치주과학회지

The purpose of this study is to evaluate histologic result of bone substituting material on defects followed tooth extraction. We compare the histologic findings control, DFDBA, Bio-Oss(R), and Regenafil(TM), Briefly, mandibular premolar teeth were extracted available for bone filling. All alveolar sites were checked after extraction and thoroughly debrided with a dental curet to remove the periodontal ligament. Extraction sites were prepared dehiscence on buccal side 7mm height from alveolar crest. The graft materials were filled into the extraction socket and dehiscenc defects. The animals were sacrificed 12 weeks after implantation. Both treated and control mandibular sites were histologically evaluated with light microscopy. Histologic observation at 12 weeks revealed that control and experimental sites were healed uneventfully and directly apposed to new bone without any adverse tissue reaction. DFDBA and Bio-Oss(R) sites maintain width of alveolar crest but were not fully resorbed. Regenafil(TM) sites also maintain width and particles were resorbed more than other graft materials. From this results, it was suggested that Regenafil(TM) is promising boen substituting materials maintaining the width of alveolar crest and height follewed tooth extraction.

The effect of PDGF-BB loaded TCP/ chitosan microgranules on new bone formation / 대한치주과학회지

The purpose of this study was to evaluate newly fabricated tricalcium phosphate(TCP)/chitosan microgranuls as bone substitutes. TCP/chitosan microgranules were fabricated by dropping TCP-chitosan suspension into the NaOH/ethanol solution. The size of microgranules could be controllable via airflow rate. PDGF-BB was loaded into the fabricated granules via freeze-drying methods(300 ng/20 mg). To evaluate cell proliferation, cultured osteoblasts cell lines(MC3T3-E1) was dropped on the BioOss(R), chitosan microgranules, TCP/chitosan microgranules and cultured for 1, 7, 14, and 28 days. Scanning electron microscopic observation was done after 7 days of culture and light microscopic examination was done after 28 days of culture. PDGF-BB release from the microgranules was tested. Rabbit calvarial defects(8 mm in diameter) were formed and chitosan, TCP/chitosan, PDGF-TCP/chitosan microgranules, and BioGran(R) were grafted to test the ability of new bone formation. At SEM view, the size of prepared microgranules was 250-1000 um and TCP powders were observed at the surface of TCP/chitosan microgranules. TCP powders gave roughness to the granules and this might help the attachment of osteoblasts. The pores formed between microgranules might be able to allow new bone ingrowth and vascularization. There were no significant differences in cell number among BioOss(R) and two microgranules at 28 day. Light and scanning electron microscopic examination showed that seeded osteoblastic cells were well attached to TCP/chitosan microgranules and proliferated in a multi-layer. PDGF-BB released from TCP/chitosan microgranules was at therapeutic concentration for at least 1 week. In rabbit calvarial defect models, PDGF-TCP/chitosan microgranules grafted sites showed thicker bone trabeculae pattern and faster bone maturation than others. These results suggested that the TCP/chitosan microgranules showed the potential as bone substitutes.

Effect of Citric Acid and Tetracycline HCl Root Conditioning on rhBMP-2 on Human Periodontal Ligament Fibroblast and Osteoblast Cell / 대한치주과학회지

The goal of periodontal treatment is predictable periodontal regeneration. But until now, many products including GTR materials and growth factors are beyond of complete regeneration. BMP can induce ectopic bone formation when implanted into sites such as rat muscle and can greatly enhance healing of bony defects when applied exogenously. BMP can promote periodontal regeneration by their ability to stimulate new bone and new cementum formation. But little is known about optimal conditions required for the application. Root conditioning is used for bioactive root change so altered root surface provides a substrate that promotes chemotaxis, migration and attachment of peridontal cells encouraging connective attachment to the denuded root surface. The aim of this study is to investigate whether the acid conditioning change effect of rhBMP-2 on human periodontal ligament cell and osteoblast cell line. 288 periodontally involved root dentin slices are divided into 6 groups, each 48, 1)control, 2)treated with BMP, 3)treated with citric acid 4)treated with citric acid+BMP 5)treated with tetracycline 6)treated with TC+BMP. Each group was devided half, so 12 root dentin slices were seeded with periodontal ligament cells and 12 were seeded with osteoblasts. At day 2 and 7, cell number, protein assay, ALP activity was measured. To investigate morphology of cultured cells, SEM was employed. Statistical analysis was performed with SPSS 8.0 either t-test or ANOVA test. The results are ; Protein assay and cell number was slightly decreased in CA+BMP group compared to CA group but it was not statistically significant and ALP activity was much more increased in CA+BMP group compared to CA group so there was no statistically significance between BMP and CA+BMP group and statistically significant compared to control group. Cell number and protein assay was slightly increased in TC group and ALP activity was much less than BMP group and CA group. Cell number and protein and ALP activity was not much increased in TC+BMP group. TC group and TC+BMP group showed cell morphology change in SEM. This results suggested that application of root surface with citric acid before BMP treatment might give better result in periodontal regeneration.

Biodegradability of porous Calcium Polyphosphate / 대한치주과학회지

The purpose of this study is to evaluate the bioresorbability of Calcium Polyphosphate added with Na2O and chitosan. Though calcium phosphate ceramics meet some of the needs for bone replacement, they have some limitation of unresorbability and fibrous encapsulation without direct bone apposition during bone remodelling. To solve these problem, we developed a new ceramic, calcium polyphosphate(CPP), and report the biologic response to CPP in extraction sites of beagle dog. Porous CPP granules were prepared by condensation of anhydrous Ca(H2PO4)2 to form non-crystalline Ca(PO3)2. CPP granules added with Na2O and chitosan were implanted in extraction sockets and histologic observation were performed at 12 weeks later. Histologic observation at 12 weeks revealed that CPP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CPP granules added with chitosan were well adatped without any adverse tissue reaction and resorbed slowly and spontaneously. CPP granules added with Na2O and chitosan show multinucleated giant cells and osteoblast-like cells around grafted material and newly formed bone. This result revealed that CPP, regardless of its additive component, had a high affinity for bone and had been resorbed slowly. From this results, it was suggested that CPP is promising ceramic as a bone substitute and addition of Na2O and chitosan help biodegradation. In further study , it will be determined which concentration of Na2O help biodegradation and the other additive components increase the degradation rate.

Biodegradability of porous Calcium Polyphosphate / 대한치주과학회지

The purpose of this study is to evaluate the bioresorbability of Calcium Polyphosphate added with Na2O and chitosan. Though calcium phosphate ceramics meet some of the needs for bone replacement, they have some limitation of unresorbability and fibrous encapsulation without direct bone apposition during bone remodelling. To solve these problem, we developed a new ceramic, calcium polyphosphate(CPP), and report the biologic response to CPP in extraction sites of beagle dog. Porous CPP granules were prepared by condensation of anhydrous Ca(H2PO4)2 to form non-crystalline Ca(PO3)2. CPP granules added with Na2O and chitosan were implanted in extraction sockets and histologic observation were performed at 12 weeks later. Histologic observation at 12 weeks revealed that CPP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CPP granules added with chitosan were well adatped without any adverse tissue reaction and resorbed slowly and spontaneously. CPP granules added with Na2O and chitosan show multinucleated giant cells and osteoblast-like cells around grafted material and newly formed bone. This result revealed that CPP, regardless of its additive component, had a high affinity for bone and had been resorbed slowly. From this results, it was suggested that CPP is promising ceramic as a bone substitute and addition of Na2O and chitosan help biodegradation. In further study , it will be determined which concentration of Na2O help biodegradation and the other additive components increase the degradation rate.

EFFECTS OF CIGARETTE SMOKING ON PERIODONTAL STATUS / 대한치주과학회지

The purposes of this study were to investigate the relationship between cigarette smoking levels and periodontal status. 199 subjects, consisting of male 127 and female 72, classified by smoking levels and duration were selected: Patients who had smoked for more than 20 cigarettes/day were considered heavy smokers, 10 to 19, moderate smokers ; 1- 9, light smokers; 0, non-smoker. And smokers were divided into ones who had smoked for more than 20 years, 10-19 years, less than 10 years and non-smokers. Heavy smokers and moderate smokers showed significantly greater pocket depths, less clinical attachment levels, more molar furcation involvements, greater alveolar bone loss and higher scores of plaque index than light smokers and non-smokers, (p < 0.05). When the duration of smoking was considered as a factor, scores of clinical parameters were worse and alveolar bone loss were significantly greater in long-term smokers, who had smoked for more than 20 years. In conclusion, cigarette smoking is associated with periodontal status.

The Effect of Bioresorbable Membrane on the Bone Regeneration of Streptozotocin Induced Diabetic Rats / 대한치주과학회지

The purpose of this study is to evaluate the effects of bioresorbable membranes in guided bone regeneration of streptozotocin induced diabetic rats. 50 Sprague-Dawley rats were randomly categorized into 4 groups: Group 1 & 2 had 10 normal rats each and group 3 & 4 included 15 streptozotocin induced diabetic rats each. Defect measuring 7mm in diameter was formed on every rat calvarium. No membrane was used in groups 1 & 3 and membranes were used in groups 2 & 4. The rates were sacrificed at 2 and 4 weeks after defect formation. Routine histological specimens were prepared. Masson-trichrome and HE stain were done before light microscopy. Guided regenerative potential was evaluated by measuring the amount of new bone formation in the calvarial defect by histomorphometry. Following results were obtained. 1.New bone formation in the diabetic groups was significantly less that than in the normal groups regardless of membrane use(p <0.05). 2.In the comparison of new bone formation in the normal groups, membrane group showed significantly more bone formation(p <0.1). 3.When the amount of new bone formation was compared in the diabetic groups, more bone was formed in the membrane groups but the difference was not statistically significant. 4.In the normal groups the amount of new bone formation was significantly greater at 4 weeks compared to that at 2 weeks(p <0.05) but amount of bone regeneration at 4 weeks was not significantly greater than that at 2 weeks in both diabetic groups.

Influence of Smoking on Short-Term Clinical Results of Periodontal Bone Defects Treated with Regenerative Therapy Using Bioabsorbable Membranes / 대한치주과학회지

This study compared the short-term(4 months) clinical results of regenerative therapy with bioabsorbable membranes(BioMesh(R)) and bone allograft for the treatment of periodontal(intrabony and furcation) defects in smokers and non-smokers.(16 smokers) 32 subjects with 92 defects participated in the study(46 in smokers and 46 in non-smokers). This study also evaluated a bioresorbable barrier with and without decalcified freezedried bone allograft(DFDBA). The 92 periodontal defects were randomly treated with either the resorbable barrier alone or resorbable barrier in combination with DFDBA following thorough defect debridement and root preparation with tetracycline. Each patient received both types of treatment modalities. Clinical examinations(probing depth, gingival recession, clinical attachment level, plaque index and gingival index) were carried out immediately before and 4 months after surgery. Significant(p<0.001) gains in mean attachment level were observed for both smokers(2.93mm) and nonsmokers(3.30mm) but there were not significant difference between two groups. Similarly, significant reductions in mean probing depthshowed for smokers(4.52mm) and non-smokers(4.26mm). However, when comparing gingival recession, smokers were found to exhibit significantly poorer treatment results(1.59mm vs 0.96mm, p<0.05). Using the split-mouth-design, no statistically significant difference between the two modalities could be detected with regard to pocket depth reduction, gingival recession, or attachment gain. These results illustrate that the attachment gain is better in the non-smoker and the best in the non-smoker with the combination therapy of resorbable barrier and DFDBA than with resorbable barrier alone but smoking had no significant effect on clinical treatment outcome, even though smokers show more significant gingival recession. In addition, both treatments, either resorbable barrier plus DFDBA or resorbable barrier alone, promoted significant resolution of periodontal defects but the addition of DFDBA with a bioabsorbable membrane appears to add no extra benefit to the only membrane treatment.

Guided bone regenerative effect of chitosan and chitosan-cellulose membranes / 대한치주과학회지

Chitosan has been known as a wound healing agent. The purpose of this study was to evaluate the biocompatibility and guided bone regenerative effect of chitosan and chitosan-cellulose membranes. The effects of chitosan and chitosan-cellulose membranes on the growth and survival of human periodontal ligament cells were examined by rapid colorimetric MTT(tetrazolium) assay, and the tissue response and resorption pattern were observed by implanting the membranes into the subcutaneous tissue of the back of rats for 6 weeks. To evaluate the guided bone regenerative potential of membranes, the amount of newly formed bone in the rat calvarial defects(8mm in diameter) was measured by histomorphometry and radiomorphometry 1,2 and 4 weeks after implantation of membranes. Chitosan and chitosan-cellulose membranes showed no adverse effect on the growth and survival of human periodontal ligament cells. When membranes were subcutaneously implanted, inflammatory reaction was observed at 1 week and which gradually subsided 2 weeks after implantation. Membranes remained intact throughout the experimental period of 6 weeks. Radiomorphometric analysis of the craniotomy sites revealed that chitosan and chitosan-cellulose membrane implanted sites showed increased radiopacity over control. Statistically significant differences with control were found in chitosan-cellulose membrane implanted group at 2 and 4 weeks, and chitosan membrane implanted group at 4 weeks(P<0.05). Histomorphometric data indicated a pattern of osseous healing similar to radiomorphometric analysis. There was a statistically significant difference between control and chitosan-cellulose membrane implanted group at 4 weeks(P<0.05). These results implicate that chitosan and chitosan-cellulose membrane might be useful for guided bone regeneration.

Strutural Change of Root Surface Following CO2 Laser Treatment / 대한치주과학회지

The purpose of this study was to evaluate the structural change of root surface and the occlusion of dentinal tubule following CO2 laser treatment. Seven extracted healthy human premolar werw curetted, sectioned, and four specimens were randomly assigned to each of 6 different treatment groups : 1) untreated EDTA etched control; 2) root plande only; 3) CO2 laser treated with 2W mode 6(10msec/pulse, 20pps) for 1 minute; 4) CO2 laser treated with 2W mode 6(10msec/pulse, 20pps) for 2 minutes; 5) CO2 laser treated with 2W mode 7(20msec/pulse, 20pps) for 1 minute; 6) CO2 laser treated with 2W mode 7(20msec/pulse, 20pps) for 2 minutes. Following the prescribed treatment, the specimens were prepared for SEM evaluation. Results showed that CO2 laser may be effective to occlude dentinal tubules tor dentin sensitivity treatment. The effect of dentinal tubule occlusion was enhanced with increasing the total energy level lased to specimen regardless of lasing mode. The structural changes of root surfaces were restricted to superficies, and these changes included fissuring, charring, crater formation over the smooth lava like texture. The charring and crater formation implying root damage was observed in the case of the longer duration of a pulse. The results of the present study suggests that the pulsed CO2 laser with shorter pulse duration and longer exposure time can be used effectively in order to obtain the optimal dentinal tubule occlusion with minimal root damage.