• Restorative Dentistry and Endodontics
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• v.44 no.1
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• pp.8.1-8.7
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• 2019

Objectives: Irrigants are imperative in endodontic therapy for the elimination of pathogens from the infected root canal. The present study compared the antimicrobial efficacy of octenidine dihydrochloride (OCT) with chlorhexidine (CHX) and sodium hypochlorite (NaOCl) against Staphylococcus epidermidis (S. epidermidis) for root canal disinfection. Materials and Methods: The minimum inhibitory concentration (MIC) was obtained using serial dilution method. The agar diffusion method was then used to determine the zones of inhibition for each irrigant. Lastly, forty 6-mm dentin blocks were prepared from human mandibular premolars and inoculated with S. epidermidis. Samples were randomly divided into 4 groups of 10 blocks and irrigated for 3 minutes with saline (control), 2% CHX, 3% NaOCl, or 0.1% OCT. Dentin samples were then collected immediately for microbial analysis, including an analysis of colony-forming units (CFUs). Results: The MICs of each tested irrigant were 0.05% for CHX, 0.25% for NaOCl, and 0.0125% for OCT. All tested irrigants showed concentration-dependent increase in zones of inhibition, and 3% NaOCl showed the largest zone of inhibition amongst all tested irrigants (p < 0.05). There were no significant differences among the CFU measurements of 2% CHX, 3% NaOCl, and 0.1% OCT showing complete elimination of S. epidermidis in all samples. Conclusions: This study showed that OCT was comparable to or even more effective than CHX and NaOCl, demonstrating antimicrobial activity at low concentrations against S. epidermidis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.45 no.3
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• pp.129-134
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• 2019

Objectives: The objective of this study was to highlight the role of lateral arthroplasty along with interposition of the buccal fat pad (BFP) in the management of Sawhney type III temporomandibular joint (TMJ) ankylosis. Materials and Methods: Ten patients with TMJ ankylosis (7 unilateral and 3 bilateral, total of 13 joints) were treated with lateral arthroplasty and BFP interposition. The bony bridge of the ankylotic mass on the lateral aspect was resected, leaving a distance of 1.5 to 2.0 cm from the base of the skull to the neck of the condyle. The condyle was left intact. Coronoidectomy was performed on the ipsilateral side via the same approach in all cases. The inter-incisal opening was measured at that time, and if it was less than 35 mm, contralateral coronoidectomy was performed by using the intra-oral approach. After satisfactory inter-incisal mouth opening (${\geq}35mm$) was achieved, the TMJ surgical site was revisited, and BFP was retrieved and used to cover the lateral aspect of the medially placed condyle. Results: With lateral arthroplasty, the medially displaced condyle can be left in-situ to maintain the mandibular ramal height and function and to act as a growth center in children. Interposition of the BFP prevents reformation of the lateral bony bridge that was removed. Conclusion: Lateral arthroplasty along with interpositioning of the BFP is a novel technique for managing Sawhney type III ankylosis that achieves management goals while avoiding complex and advanced reconstructive surgical procedures.

• Journal of Periodontal and Implant Science
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• v.48 no.6
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• pp.395-404
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• 2018

Purpose: The purpose of this study was to propose a technique for periodontal biotype modification through thickening of the entire facial aspect using a volume-stable collagen matrix and autogenous subepithelial connective tissue graft (CTG) for the treatment of gingival recession. Methods: Four systemically healthy patients showing Miller class I or class II gingival recession in the mandibular incisor area were included in this study. Full-mouth scaling and root planing procedures were performed at least 4 weeks prior to periodontal plastic surgery. A split-thickness flap with a horizontal intrasulcular incision and 2 vertical incisions was used in cases 1-3, and the modified tunnel technique was used in case 4 for coronal advancement of the mucogingival complex. After the exposed root surfaces were debrided thoroughly, double-layered volume-stable collagen matrix was placed on the apical part of the recession and a subepithelial CTG harvested from the palatal area was placed on the coronal part. The amount of root coverage at 3 months postoperatively was evaluated in cases 1-3, and facio-lingual volumetric changes were analyzed in cases 1 and 2. Results: Healing was uneventful in all 4 cases and complete root coverage was shown in cases 1-3. In case 4, reduction of gingival recession was observed at 3 months after surgery. In cases 1 and 2, a comparison of stereolithographic files from the preoperative and postoperative time points demonstrated that the entire facio-lingual volume had increased. Conclusions: The surgical technique suggested herein, using a volume-stable collagen matrix and autogenous subepithelial CTG, may be an effective method for periodontal biotype modification through thickening of the entire facial aspect for the treatment of gingival recession.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.2
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• pp.94-100
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• 2022

Objectives: This study aimed to compare the effects of systemic administration of levofloxacin or cephalexin on fracture healing in rats. Materials and Methods: In this animal study, tibial fractures not requiring fixation were artificially induced in 30 male Wistar albino rats using a 1.1 mm surgical bur. The rats were randomly divided into 6 groups (n=5). Groups 1 and 2 received daily subcutaneous saline injections. Groups 3 and 4 received subcutaneous injections of 25 mg/kg levofloxacin twice daily. Groups 5 and 6 received daily subcutaneous injections of 20 mg/kg cephalexin. The rats in Groups 1, 3, and 5 were sacrificed after 1 week, while the rats in Groups 2, 4, and 6 were sacrificed after 4 weeks. The score of fracture healing was determined through histological assessment of sections from the fracture site according to Perry and colleagues. Data were analyzed by Kruskal-Wallis and Mann-Whitney tests. Results: The mean score of fracture healing at 4 weeks was significantly higher than that at 1 week in the saline, levofloxacin, and cephalexin groups (P<0.001). At 1 week, no significant difference was noted among the three groups of saline, levofloxacin, and cephalexin in the mean score of fracture healing (P=0.360). However, this difference was significant at 4 weeks (P=0.018), and the mean score in the saline group was significantly higher compared to that in the levofloxacin group (P=0.015). Conclusion: It is recommended not to prescribe levofloxacin for more than 1 week after surgical management of bone fractures due to its possible adverse effects on fracture healing.

• Imaging Science in Dentistry
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• v.53 no.2
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• pp.137-144
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• 2023

Purpose: This study aimed to evaluate the anatomic circle around the impacted lower third molar to show, document, and correlate essential findings that should be included in the routine radiographic assessment protocol as clinically meaningful factors in overall case evaluation and treatment planning. Materials and Methods: Cone-beam computed tomographic images of impacted lower third molars were selected according to specific inclusion criteria. Impacted teeth were classified according to their position before assessment. The adjacent second molars were assessed for distal caries, distal bone loss, and root resorption. The fourth finding was the presence of a retromolar canal distal to the impaction. Communication with the dentist responsible for each case was done to determine whether these findings were detected or undetected by them before communication. Results: Statistically significant correlations were found between impaction position, distal bone loss, and detected distal caries associated with the adjacent second molar. The greatest percentage of undetected findings was found in the evaluation of distal bone status, followed by missed detection of the retromolar canal. Conclusion: The radiographic assessment protocol for impacted third molars should consider a step-by-step evaluation for second molars, and clinicians should be aware of the high prevalence of second molar affection in horizontal and mesioangular impactions. They also should search for the retromolar canal due to its associated clinical considerations.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.11 no.1
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• pp.101-116
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• 1989

Proplast and Porous Polyethylene which have porous structures as low-modulus polymers have been recently used in maxillofacial plastic and reconstructive surgery. The purpose of this study was to compare the response of adajacent tissue, new bone formation and stability after augmentation by differen methods of subperiosteal graft using proplast and purous polythylene in rabbit mandible. The augmentation procedure was carried out by dividing into two groups, A and B. A group consisted of subperiosteal graft on the cortex, and the other B group was made up only graft following artificial decortication in the mandibular body of rabbit. The experimental animals were sacrificed on the 1st, 2nd, 4th and 8th week after grafting for macroscopic and light microscopic examination. The samples extracted at the 6th postgrafting week were also used for biometric testing and scanning electron microscopic examination. The results obtained from this study were as follows : 1. Macroscopically, infection of graft site, deformation and migration of graft material were not observed in all experimental groups. 2. B group showed more rapid and increased bone formation and the greater stability than A group, and tissue response was similar to each other. 3. In the tissue response, macrophages and cellular infiltrations were observed in Proplast group, but few in PHDPE group. 4. In bone formation of A group, Proplast group showed no bone formation until the 8th week, but PHDPE group showed small quantity of osteoid tissue from the 2nd week and appositional bone growth with new bone formation at the 8th week. 5. In bone formation of B group, both Proplast and PHDPE group showed bone formation, but PHDPE group showed more rapid and larger bone formation. 6. In pattern of bone formation, Proplast group mainly showed appositional bone growth pattern connected with graft site. On the other hand, PHDPE group showed mixed pattern of new bone formation in the pore connective tissue with appositional bone growth from graff site. 7. The maximum mean values of shear stress were serially $111.3gf/mm^{2}$ in PHDPE of B group, $84.8gf/mm^{2}$ in PHDPE of A group, $32.9gf/mm^{2}$ in Proplast B group, and $15.7gf/mm^{2}$ in Proplast of A group. From above results, It was suggested that the capacity of bone formation and stability between bone and graft material were dependent on the pore size and structure of graft material itself, the state of graft site and tissue response.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.341-345
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• 2010

Introduction: Skeletal homeostasis is normally maintained by the stability between bone formation by osteoblasts and bone resorption by osteoclasts. However, the correlation between the inflammatory reaction and osteoblastic differentiation of cultured osteoprogenitor cells has not been fully investigated. This study examined the effects of inflammatory cytokines on the osteoblastic differentiation of cultured human periosteal-derived cells. Materials and Methods: Periosteal-derived cells were obtained from the mandibular periosteum and introduced into the cell culture. After passage 3, the periosteal-derived cells were further cultured in an osteogenic induction Dulbecco's modified Eagle's medium (DMEM) medium containing dexamethasone, ascorbic acid, and $\beta$-glycerophosphate. In this culture medium, tumor necrosis factor (TNF)-$\alpha$ with different concentrations (0.1, 1, and 10 ng/mL) or interleukin (IL)-$1{\beta}$ with different concentrations (0.01, 0.1, and 1 ng/mL) were added. Results: Both TNF-$\alpha$ and IL-$1{\beta}$ stimulated alkaline phosphatase (ALP) expression in the periosteal-derived cells. TNF-$\alpha$ and IL-$1{\beta}$ increased the level of ALP expression in a dose-dependent manner. Both TNF-$\alpha$ and IL-$1{\beta}$ also increased the level of alizarin red S staining in a dose-dependent manner during osteoblastic differentiation of cultured human periosteal-derived cells. Conclusion: These results suggest that inflammatory cytokines TNF-$\alpha$ and IL-$1{\beta}$ can stimulate the osteoblastic activity of cultured human periosteal-derived cells.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.5
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• pp.571-577
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• 2008

Introduction: Possible etiologic factors associated with bone loss around implants after implantation are surgical trauma, occlusal overload, periimplantitis, presence of micro gap and the formation of biologic distances. Tarnow et al. observed that the crestal bone loss was greater when the distance between the implants was <3mm than when the implants were ${\geq}\;3mm$ apart. The aim of this study was to evaluate the influence of different interimplant distance on marginal bone and crestal bone resorption in the beagle dogs. Materials and methods: The mandibular premolars of 5 dogs were extracted bilaterally. After 12 weeks of healing, each dog received 7 implants. On each side, implants were separated by 2mm (Group 1) and by 5mm (Group 2). After 16 weeks of healing, the dogs were sacrificed. Marginal bone loss was determined through linear measurements made between the implant-abutment junctions and the most coronal portions of the bone in contact with the implant surface. A line was drawn uniting the implant-abutment junctions of the adjacent implants, and a linear measurement was made at the midpoint in the direction of the most coronal peak of the interimplant bone crest to determine the crestal bone loss. Both of them was measured radiologically and histologically. Result and conclusion: In radiological analysis, the mean of marginal bone loss was $1.26{\pm}0.14mm$ for group 1 and $1.23{\pm}0.34mm$ for group 2, the mean of crestal bone loss was $1.10{\pm}0.14mm$ for group 1 and $1.02{\pm}0.30mm$ for group 2. The results were not statistically significant between 2 groups. In histological analysis, the mean of marginal bone loss was $1.63{\pm}0.48mm$ for group 1 and $1.62{\pm}0.50mm$ for group 2, the mean of crestal bone loss was $1.23{\pm}0.35mm$ for group 1 and $1.15{\pm}0.39mm$ for group 2. The differences were also not statistically significant. The clinical significance of this result is that the increase in the crestal bone loss results in the increase in the distance between the base of the interproximal contact of the crowns and the bone crest, and this determines if papilla will be present or absent between implants. Considering this fact, keeping up sufficient interimplant distance is important to minimize crestal bone loss.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.29 no.2
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• pp.123-131
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• 2007

Introduction: Distraction osteogenesis is widely used as for bone lengthening in patients with maxillofacial deformity and alveolar bone atrophy. One of the major problems in distraction osteogenesis is long consolidation period for 2-3 months, in which the devices have to be fixed on the bone to prevent relapse. It results in scar formation on the face, disturbance of mastication and speech. This study was performed to evaluate the stimulating effect of pulsed electromagnetic field on the early bone consolidation in distraction osteogenesis. Materials and methods: Total 10 rabbit were used (5 for control group, 5 for experimental group). A vertical osteotomy in the mandibular body was performed and the distraction device was fixed. After 5 days distraction was done 1mm per a day for 7 days. A pulsed electromagnetic field (38 Gauss, 60 Hz) was applied for 8 hours per day and it continued for 5 days immediately after distraction in the experimental group. Both groups were sacrificed after 2 weeks. Histological specimens with H&E and Masson Trichrome staining were made and histomorphometrically analysed with image analyser. Results: The device for distraction osteogenesis was displaced in one animal for each group, therefore, only four animals in both groups were evaluated. In both groups, a new bone formation was observed in the distracted area after 2 weeks. The bone formation was enhanced in the experimental groups ($31.76{\pm}8.68%$) compared with control group ($9.94{\pm}3.23%$), its difference was statistically significant (p<0.001). Conclusion: This study suggests that electrical stimulation with electromagnectic field may be effective in the early bone formation after distraction osteogenesis. Further studies with large number of animals are needed before clinical application.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.19 no.4
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• pp.367-376
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• 1997

The 234 patients who received treatment of midfacial fractures at the Department of Oral and Maxillofacial Surgery of Chonnam University Hospital from Jan. 1, 1992 to Dec. 31, 1996 were analyzed clinicostastically. Results obtained were as follows ; Male predominated over females by a ratio of 5.3 to 1. The frequently developing age groups were first 3rd (25%), 4th (21%) and the 2nd (18%) decade on succession. The peakest month was the August (16%), and May (11%), September (9%), October (9%). When it comes to the reasons for in-patients, traffic accident was predominant to 38%. In the 234 cases of midfacial fractures, zygomaticomaxillary complex fracture was the most by 37%. The most common with injury show that facial laceration marked by 49%, neurologic injury 24%, and mandibular fracture 20% each by each. About the time from injury onset to operation, 55% of cases were less than a week while the others (45%) more than a week. 3 plates were used for operation : 2 for zygoma or maxilla fracture and 3 for zygomatiomaxillary complex fracture. especially 4 for Le Fort I fracture, 5.5 for Le Fort I, II ; I, III ; II, III fracture, 7 for Le Fort I,II,III fracture were used. 20 patients (8%) appealed their complication and the most common was reported as infection. Above results suggest that early diagnosis and treatment of fracture site, systemic condition and associated injuries are necessary, and coorperative treatment with medical department should be performed.