• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.1
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• pp.16-22
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• 2010

Objective: Bisphosphonate related osteonecrosis of the jaw (BRONJ) is reported in patients taken bisphosphonate for a long time, however, the mechanism of osteonecrosis in BRONJ was not clarified yet. This study was designed to investigate the effect of short administraion zoledronate on the healing pattern of periosteum and sinus membrane after iliac bone graft into maxillary sinus. Methods: In this study, 18 Newzeland rabbits were used. The animals were divided into 2 group. In the experimental group, rabbits were treated with weekly peritoneal injection (0.06 mg/kg/week) of zoledronate for three times. In the control group, rabbits were treated with saline solution injection instead of zoledronate. Periosteum and sinus membrane were harvested from one rabbit of the experimental group and one of the control group in the fourth week. The autogeneous bone was harvested from ilium and grafted into maxillary sinus. The rabbits were sacrificed at 1, 2, 4 and 8 weeks after bone graft. The healing pattern of periosteum and sinus membrane were evaluated histologically. Results: Inflammatory reaction in the periosteum was less conspicuous and healing process appeared earlier in experimental group compared with control group at 1, 2, 4 weeks. There were no differences of microscopic findings of sinus membrane between both groups at any weeks. Conclusion: Short-term use of zoledronate decreased the inflammatory reaction and enhanced healing process in the periosteum. These findings suggest the possibility that zoledronte suppress the function of macrophages.

• Archives of Plastic Surgery
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• v.44 no.3
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• pp.194-201
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• 2017

Background Platelet-rich plasma (PRP) contains high concentrations of growth factors involved in wound healing. Hydrogel is a 3-dimensional, hydrophilic, high-molecular, reticular substance generally used as a dressing formulation to accelerate wound healing, and also used as a bio-applicable scaffold or vehicle. This study aimed to investigate the effects of PRP and hydrogel on wound healing, in combination and separately, in an animal wound model. Methods A total of 64 wounds, with 2 wounds on the back of each nude mouse, were classified into 4 groups: a control group, a hydrogel-only group, a PRP-only group, and a combined-treatment group. All mice were assessed for changes in wound size and photographed on scheduled dates. The number of blood vessels was measured in all specimens. Immunohistochemical staining was used for the analysis of vascular endothelial growth factor (VEGF) expression. Results Differences in the decrease and change in wound size in the combined-treatment group were more significant than those in the single-treatment groups on days 3, 5, 7, and 10. Analysis of the number of blood vessels through histological examination showed a pattern of increase over time that occurred in all groups, but the combined-treatment group exhibited the greatest increase on days 7 and 14. Immunohistochemical staining showed that VEGF expression in the combined-treatment group exhibited its highest value on day 7. Conclusions This experiment demonstrated improved wound healing using a PRP-hydrogel combined treatment compared to either treatment individually, resulting in a decrease in wound size and a shortening of the healing period.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.3
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• pp.216-221
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• 2009

Purpose: The retention of the basement membrane complex, which was the unique feature of the acellular dermal matrix ($AlloDerm^{(R)}$), plays an important role in the normal process of wound healing. The present study was aimed to compare the healing of the acellular dermal matrix according to the graft method in the rabbit ear. Materials and methods: Six mature rabbits weighing about 3.0 kg were used, $10\;{\times}\;5\;mm$ sized subcutaneous pockets were created between the ear skin and the underlying perichondrium. In the control group, the acellular dermal matrix was grafted with the basement membrane facing toward the perichondrium. On the contrary, the acellular dermal matrix was grafted with the basement membrane facing toward the skin side in the experimental group I. In the experimental group II, the acellular dermal matrix was grafted like rolled configuration with basement membrane side in. The grafted site was picked at 3, 7, and 21 days after the graft. Serial sections were processed by H-E stain and examined under light microscopy to assess the healing patterns. Results: There was no distinct volume loss in the gross examination, but resorption was observed from the edge of the acellular dermal matrix in the histological examination. The space of resorption was replaced by the newly formed fibrous tissues and vessels. The inflammatory cells were more increased at 7 days after the graft than the early days. However, inflammation was decreased at 21 days after the graft. Regardless of the graft direction, no differences were observed between the control and the experimental group I in the healing patterns. Conclusion: These results suggest that the acellular dermal matrix can be used simply and effectively without regard to the graft direction as a substitute of autogenous material for repairing soft tissue defect.

• Journal of Periodontal and Implant Science
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• v.26 no.4
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• pp.823-840
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• 1996

The purpose of this study was to evaluate the effect of dexamethasone on the healing aspect of gingiva and alveolar bone after extraction. Extracted socket of 24 Sprague-Dawley rat was used. To extract easily and minimize injury, ${\beta}-APN$ 0.2g/kg/day soluted in mineral water was administrated for 5 days before extraction in both group. Ampicillin 1.5ml/kg i.m.,q.d, was administered for preventing infection after teeth extraction in both group, and dexamethasone 0.2mg/kg/day was injected for 3 days in experimental group.3 rats on each day was sacrificed on 1, 3, 7, 15 days after extraction. Histologic examination and the activity of osteoclasts by tartrate resistant acid phosphatase was observed. The results were as follows : 1. The Overall healing pattern was similar with both the experimental and control group, but in experimental group osseous healing was delayed. 2. The activity of osteoclasts was increased to day 3 and then decreased after day 3 in the experimental group. In comparison to the control group, the experimental group showed increased appearance to day 7 and then decreased appearance following day. 3. Regarding to the change of osseous tissue, the activity of osteoblasts was shown at day 7,but osteoclastic activity of the experimental group was less than that of the control group. The osteoclastic activity was statistically significant between two groups except day 7(p<0.05, p<0.01). In conclusion, the effects of dexamethasone for healing of extraction socket were considered as limiting the activity of osteoclasts, and the healing of extraction socket was delayed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.26 no.4
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• pp.369-372
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• 2000

The purpose of this study was to investigate the distribution pattern of CGRP immunoreactive nerve fibers in the healing mucosa of extracion wound. Maxillary 1st molars of rats were extracted. All extraction sites and adjacent tissues of 3 groups of rats(1-week, 2-week and 4-week groups) were removed en bloc and processed for immunostaining and were subjected to light microscopic examination. The results obtained were as follows; In 1-week group, there was no difference in the distribution pattern of CGRP immunoreactive nerve fiber between epithelial margin adjacent to extraction socket and normal gingival epithelium. In 2-week group, some CGRP-immunoreactive nerve fibers were seen in epithelial layer. In 4-week group, many intercellular CGRP immunoreactive nerve fibers were abundant in all layers of immature epithelium characterized by scab on the mucosa and thick keratinized cell layer with irregular surface. Intraepithelial CGRP immunoreactive nerve fibers were reduced to normal level in adjacent mature epithelium. These results suggest that density of CGRP immunoreactive nerve fibers are increased transiently in epithelium during reepithelialization process and CGRP released from these nerve fibers may play an important role in the reepithelialization in the wound healing.

• Imaging Science in Dentistry
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• v.39 no.1
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• pp.19-25
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• 2009

Purpose: To longitudinally observe the healing process of extracted socket and the alterations of the residual ridge in healthy adult dogs using cone beam CT (CBCT). Materials and Methods: The mandibular premolars of two beagle dogs were removed and the extraction sites were covered with the gingival tissue. CBCTs (3D X-ray CT scanner, Alphard vega, Asahi Co.) were taken at baseline and at 1 week interval for 12 weeks. Radiographic density of extracted wounds was measured on normalized images with a custom-made image analysis program. The amount of alveolar crestal resorption after the teeth extraction was measured with a reformatted three-dimensional image using CBCT. Bony healing pattern of extracted wound of each group was also longitudinally observed and analyzed. Results: Dimensional changes occurred during the first 6 weeks following the extraction of dogs' mandibular premolars. The reduction of the height of residual ridge was more pronounced at the buccal than at the lingual aspect of the extraction socket. Radiographic density of extracted wounds increased by week 4, but the change in density stabilized after week 6. New bone formation was observed at the floor and the peripheral side of extracted socket from week 1. The entrance of extracted socket was sealed by a hard-tissue bridge at week 5. Conclusion: The healing process of extracted wound involved a series of events including new bone formation and residual ridge resorption.

• Journal of Oral Medicine and Pain
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• v.19 no.1
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• pp.33-43
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• 1994

The purpose of this paper was to observe the influence of Ga-As semiconductor-low power generating laser on she appearance and actions of tenascin, extracellular matrix, as healing process of intentional wound on the experimental animals is taking place. 35 rabbits were divided into control and experimental group. ; and on each, 3mm-long and 2mm-deep, surgical wounds were created on buccal oral mucosa and thoracodorsal portion of skin. Ga-As laser was applied to the experimental group starting a day of the day the wounds were created , the laser was applied for 5 minutes every other day. Tissue samples were taken after the 2, 4, 7, 10, and 14 days after wound formation. Then tile healing process of experimental and control groups were observed and compared, using light microscope. Afterwards, the samples were immunohistochemical stained and again observed tenascin by quantitative measuring. The following results were obtained : 1. Tenascin was observed prevalently on epithelial cells, border area of dermis, and interstitial matrix between connective tissue layers in both experimental and control groups. 2. In oral mucosa, the experimental group showed significant increase in the appearance of tenascin after 4 days compared to the control group, but after 10 days, it decreased to a point which is even less than the control group. 3. In the skin samples, the pattern of appearance of tenascin was the same in both groups, but there was some difference concerning when the peak period was shown, In the experimental group, the peak period of tenascin expression was the 7 days after wound formation in epithelium and connective tissue. In the control group, the peak period was 10 days after. 4. In both the experimental and control groups, tenascin first appeared in the epithelium near the wound area and submucosa, and then spread on the underlying connective tissue. In conclusion, appearance of tenascin is closely related to regeneration of epithelium and development of granulation tissue : therefore, low power laser, which fastnes appearance of tenascin, is sure to faciltate healing process of oral mucosa.

• Imaging Science in Dentistry
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• v.33 no.1
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• pp.5-14
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• 2003

Purpose: To observe the histologic pattern of healing in molar tooth extraction sockets of streptozotocin-induced diabetic rats following irradiation. Materials and Methods: Mature Sprague-Dawley rats were divided into three groups: control, diabetic, and diabetic-irradiated groups. Diabetes mellitus was induced by injecting streptozotocin. Control rats were injected with a citrate buffer only. After 5 days, the right maxillary first molar was extracted under general anesthesia from each of the rats. After the extraction, rats in the diabetic-irradiated group were irradiated with a single absorbed dose of 10 Gy to the head and neck region. The rats were killed at 1, 3, 7, 14, 21, and 28 days after treatment. Tissue sections were stained with hematoxylin-eosin and Masson's trichrome. Results: In the diabetic and diabetic-irradiated groups, the early healing process of the socket extraction was similar to the control group, but bone formation was delayed at 7 days after the treatment. In the diabetic-irradiated group, alveolar bone surrounding the extraction socket showed signs of necrosis at 3 days after treatment, and hemorrhage was observed in connective tissue within the extraction socket at 14 days after treatment. Conclusion: This experiment revealed that the healing process of the extraction socket was severely delayed and retarded by irradiation in the diabetic state.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.12 no.1
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• pp.105-113
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• 1982

Because of the development of rampant caries, osteomyelitis and osteoradionecrosis that occur after radiation therapy of oral cancers, extraction of teeth at or near the malignant lesion has been done in the past. Few, however, have studied the radiation effect on the healing of extraction wounds. This study is concerned with the effect of Co-60 irradiation on the healing process of extraction wounds in rats. Fifty six, male, Spraque-Dawley rats are used. The right first molar of the mandible is extracted from all animals. They are divided into three experimental groups of 14 each and a control group of 14. Three experimental groups are irradiated respectively with 200 rad, 400 rad and 600 rad and a pair of rats in each group are killed on days 1, 3, 5, 7, 14, 21 and 28 after irradiation. Two animals from the control group are killed on the day when the experimental rats are killed. The irradiated hemimandibles are fixed in 10% neutral formalin, decalcified in 5% trichloroacetic acid, embedded in paraffin and sectioned. The sections are stained in hematoxylin and eosin, van Gieson, Masson's trichrome or silver nitrate. Results show that in general radiation effects on healing extraction wounds are dose dependent; i.e., the higher is the dose, the greater is the histologic changes observed: 1. Irradiation tends to retard blood clot organization and epithelial regeneration. 2. An increase in the number of giant cells and osteoclasts is noted after irradiation. 3. Formation of regenerating connective tissues around and within the extraction site is com- promised, and a clear reduction of primitive mesenchymal type connective cells is noted. 4. The healing process begins along the lateral aspect of the extraction socket in the control, while irregular histologic appearances of the brabecular pattern is present in the experimental rats.

• Journal of Periodontal and Implant Science
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• v.49 no.1
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• pp.47-57
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• 2019

Purpose: This study was designed to observe the resorption pattern of biphasic calcium phosphate (BCP) used for maxillary sinus augmentation over a 3- to 6-year healing period, and to investigate factors affecting the resorption of BCP. Methods: A total of 47 implants placed in 27 sinuses of 22 patients were investigated. All patients had residual bone height less than 5 mm at baseline. The modified Caldwell-Luc approach was used to elevate the maxillary sinus membrane, and the sinus cavity was filled with BCP (70% hydroxyapatite and 30% ${\beta}$-tricalcium phosphate). Implant placement was done simultaneously or in a staged manner. Serial radiographic analysis was performed up to 6 years postoperatively. Results: During the follow-up period, no implant loss was reported. The mean reduced height of the augmented sinus (RHO) was $0.27{\pm}1.08mm$ at 36 months, and $0.89{\pm}1.39mm$ at 72 months postoperatively. Large amounts of graft material (P=0.021) and a long healing period (P=0.035) significantly influenced the amount of RHO. In particular, there was a significant relationship between a healing period longer than 40 months and RHO. Conclusions: BCP can achieve proper dimensional stability with minimal reduction of the graft height in a 3- to 6-year healing period after maxillary sinus augmentation. The healing period and the amount of graft material influenced the resorption of BCP.