• Journal of the Korean Wood Science and Technology
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• v.47 no.2
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• pp.221-228
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• 2019

This study reports the performance of urea-formaldehyde (UF) resins prepared at two different low formaldehyde/urea (F/U) mole ratios with different numbers of urea addition during synthesis. The second or third urea was added during the synthesis of UF resins to obtain two different low molar ratios of 0.7 and 1.0, respectively. The molecular weights, cure kinetics, and adhesion performance of these resins were characterized by the gel permeation chromatography, differential scanning calorimetry, and tensile shear strength of plywood, respectively. When the number of urea additions and F/U molar ratio increased, the gelation time decreased, whereas the viscosity and molecular weight increased. Further, the UF resins prepared with the second urea and 1.0 molar ratio resulted in greater activation energy than those with third urea and 0.7 molar ratio. Tensile shear strength and formaldehyde emission (FE) of the plywood that bonded with these resins increased when the number of urea additions and molar ratio increased. These results suggest that the UF resins prepared with 0.7 molar ratio and third urea addition provide lower adhesion performance and FE than those resins with 1.0 mole ratio and the second urea addition.

• The Journal of the Korean dental association
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• v.50 no.9
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• pp.566-573
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• 2012

Purpose : This study evaluated the impact of the presence and aspect of mandibular third molars to the mandible angle fracture or condyle fractures in Korean. Materials and Methods : A retrospective study was designed for patients attending the division of Oral and Maxillofacial Surgery, Kang-dong sacred heart hospital for treatment of mandibular fracture from January 2006 to September 2010. The primary variable was the presence of mandibular third molar and the secondary variable was the aspects of third molar impaction. Mandibular third molars were classified by the impaction depth and the available space as Pell & Gregory system. Outcome variables were the presence of mandibular angle fracture or condyle fracture. Also the source of trauma, age, sex were studied. Hospital charts, radiographs were used for study. Statistic analysis was done with descriptive statistics, the X2-test, linear-by-linear association. P value under 0.05 was considered significant statistically. Results : The number of involved patients was 86. The ratio of male to female patients was about 9:1 for angle fracture and 7:3 for condyle fracture. The most common source of trauma was assault for angle fracture and fall down for condyle fracture. The presence of mandibular third molar increased frequency of angle fracture and decreased condyle fracture with larger impaction depth. But available space of mandibular third molar did not show high association with angle or condyle fractures. Conclusion: Preventive extraction of mandibular third molar is recommended for patients with high risk of angle fracture. Male patients at their third decade or martial artists, police officer could be the case. But it is not recommended for patients with low risk of angle fracture and high risk of condyle fracture relatively. Elder female patients without any symptom on their third molar could be the case.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.2
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• pp.137-141
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• 2011

The extraction of an impacted third molar tooth is associated with many complications during the procedure and postoperative care. These complications include bleeding, swelling, pain, infection, as well as root fracture, proximal tooth injury, alveolar bone fracture, lingual nerve and inferior alveolar nerve injury etc. With the exception of a fractured root dislocation in the submandibular space, no direct submandibular gland injury related to extraction surgery has been reported until now. A 40 year old man visited the department of oromaxillofacial surgery at Yeouido St. Mary's Hospital for an extraction of the right mandible third molar. A partial third molar impaction was diagnosed by a clinical and radiographic examination. A surgical tooth extraction was practiced including buccal cortical bone osteotomy. During socket curettage, an encapsulated cyst-like lesion and a verified $3{\times}3\;cm$ neoplasm in the apically lingual direction were found during process of dissection. A biopsy confirmed that the neoplasm involved the submandibular gland and nerve trunk. This unusual anatomical organ injury during the surgical tooth extraction procedure is reported as a new complication during impacted third molar extraction.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.1
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• pp.2-12
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• 2023

The current study aimed to explore the types and frequencies of uncommon complications associated with third molar extractions based on a scoping review of case reports and case series. The study used an electronic literature search based on PubMed and Embase up to March 31, 2020, with an update performed on October 22, 2021. Any case reports and case series that reported complications associated with third molar extractions were included. The types of complications were grouped and the main symptoms of each type of complication were summarized. A total of 51 types of uncommon complications were identified in 248 patients from 186 studies. Most types of complications were post-operative. In the craniofacial and cervical regions, the most frequent complications included iatrogenic displacement of the molars or root fragments in the craniofacial area, late mandibular fracture, and subcutaneous emphysema. In other regions, the most frequent complications include pneumomediastinum, pneumorrhachis, pneumothorax, and pneumopericardium. Of the patients, 37 patients had life-threatening uncommon complications and 20 patients had long-term/irreversible uncommon complications associated with third molar extractions. In conclusion, a variety of uncommon complications associated with third molar extractions were identified. Most complications occurred in the craniofacial and cervical regions and were mild and transient.

• Journal of Technologic Dentistry
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• v.11 no.1
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• pp.65-70
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• 1989

The development of the lobe pattern in the human dentition plays a part in the form and function of each individual teeth. In order to determin the morphological categories used to describe the occlusal surfaces of the maxillary and mandibular molars, the variation of the developmental grooves which separate each lobe in the molars was examined and analysed. The obtained conclusions were as follow. 1. Most of the maxillary first molars with more distinct and more developmental grooves than the other molars but in most cases of the third molar, a heart-shaped outline due to poorly developed or abscent distolingual cusp was most frequent and in this case the third molar had the 3 cusps separated by the central developmental groove and the buccal developmental groove. 2. In most cases, the mandibular first molar had the 5-cusp type that the groove patter resembles a Y, the second molar the 4-cusp type arranged in such a way that the buccal and lingual developmental grooves meet the central developmental groove at right angle on the occlusal surface and many instances of the mandibular third molars had the 5-cusp thpe with a+groove pattern which separatess the mesiolingual cusp from the distobuccal cusp and the 4-cusp type with a+groove pattern. 3. The maxillary and mandibular third molar were most variable in the developmental groove.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.16 no.2
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• pp.167-170
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• 1994

The surgical removal of the wisdom teeth is obligate when forceps extraction fails or when the wisdom teeth are impacted. The surgical removal of impacted maxillary third molars is a commonly performed procedure usually associated with few complications & little morbidity. The most frequent complications are tooth root fracture, maxillary tuberosity fracture, tooth displacement into the maxillary sinus & oroantral fistula formation. A rarely reported complication is the displacement of a tooth into the infratemporal fossa. The method of prevention of this complication is by the placement of either a finger or periosteal elevator posterior to the tooth during extraction. To remove the displaced upper third molar is very difficult & has many complications, e.g., persistent bleeding & nerve damage. When the wisdom teeth is displaced, it is initially necessary to gain access to bone by developing a mucoperiosteal path of delivery is developed by additional bone removal or, preferably planned sectioning of the tooth. There are many approaching techniques to remove the displaced upper third molar. This following report describes the surgical technique of displaced upper third molar in the pterygopalatine fassa by the midpalatal ＆transpharyngeal approach.

• Journal of Dental Anesthesia and Pain Medicine
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• v.21 no.6
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• pp.575-582
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• 2021

Background: The aim of this randomized, triple-blind trial was to determine the anesthetic, analgesic, and hemodynamic effects of articaine and bupivacaine in the extraction of impacted mandibular third molar teeth. Methods: Twenty-six patients who underwent removal of bilaterally symmetric mandibular third molars were randomly assigned to articaine and bupivacaine groups in a split-mouth design. The onset of anesthetic action, intraoperative comfort, total amount of solution used, duration of postoperative anesthesia and analgesia, rescue analgesic use, postoperative pain, intraoperative bleeding, and hemodynamic parameters were evaluated. Results: In the articaine group, the onset of anesthetic activity was faster, intraoperative comfort was greater, and effective anesthesia required less local anesthetic solution. The bupivacaine group showed a significantly longer duration of postoperative anesthesia and analgesia, in addition to lower visual analog scale values at 6 and 48 hours postoperatively. There were no significant differences between the two solutions regarding rescue analgesic medication use, intraoperative bleeding, or hemodynamics. Conclusion: Articaine showed greater clinical efficacy than bupivacaine in intraoperative anesthesia, achieving faster onset of anesthetic action and greater patient comfort while also requiring less reinforcement during surgery. However, bupivacaine was superior in terms of postoperative anesthesia, reducing postoperative pain due to its residual anesthetic and analgesic effects. Both anesthetic solutions led to similar hemodynamics at low doses in mandibular third molar surgery

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.2
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• pp.91-95
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• 2023

This study examined the effects of a vertical incision on postoperative edema after third molar extraction. The study design was that of a comparative split-mouth approach. Evaluation was performed via magnetic resonance imaging (MRI). Two patients with homogeneous bilateral impacted mandibular third molars were enrolled. These patients underwent facial MRI within 24 hours after simultaneous extraction surgery. Modified triangular flap and enveloped flap incisions were made. Postoperative edema was evaluated by MRI and was assessed according to anatomical space. The two pairs of homogeneous extractions demonstrated that vertical incisions were associated qualitatively and quantitatively with extensive postoperative edema. The edema associated with these incisions spread toward the buccal space, beyond the buccinator muscle. In conclusion, a vertical incision with mandibular third molar extraction was related to edema in the buccal space and the fascial space, which contributed to clinical facial swelling.

• Journal of Dental Anesthesia and Pain Medicine
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• v.16 no.2
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• pp.95-102
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• 2016

Background: Surgery on the lower impacted third molar usually involves trauma in the highly vascularized loose connective tissue area, leading to inflammatory sequelae including postoperative pain, swelling, and general oral dysfunction during the immediate post-operative phase. This study aimed to investigate the effectiveness of preoperative injection of a single dose of 8 mg dexamethasone for postoperative pain control in lower third molar surgery. Methods: A controlled, randomized, split-mouth, prospective study involving lower third molar surgery was performed in 31 patients. The randomized sampling group was preoperatively injected, after local anesthesia, with a single dose of dexamethasone (8 mg in 2 ml) through the pterygomandibular space; 2 ml of normal saline (with no dexamethasone) was injected as a placebo. Results: The pain VAS score was significantly different on the day of the operation compared to the first post-operative day (P = 0.00 and 0.01, respectively), but it was not significantly different on the third and seventh postoperative day between the control and study groups. There was a significant reduction in swelling on the second postoperative day, and a difference between the second postoperative day and baseline value in the study group (P < 0.05). Trismus was highly significantly different on the second postoperative day and between baseline and second postoperative day between the groups (P = 0.04 and 0.02, respectively). Descriptive statistics and independent-samples t- test were used to assess the significance of differences. Conclusions: Injection of 8 mg dexamethasone into the pterygomandibular space effectively reduced the postoperative pain and other postoperative sequalae.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.1
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• pp.26-29
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• 2015

Objectives: The purpose of this study is to retrospectively evaluate the postoperative complication rates for absorbable type-I collagen sponge (Ateloplug; Bioland) use in third molar extraction. Materials and Methods: From January to August 2013, 2,697 total patients undergoing third molar extraction and type-I collagen sponge application in the Department of Oral and Maxillofacial Surgery at Yonsei University Dental Hospital (1,163 patients) and Dong-A University Hospital (1,534 patients) were evaluated in a retrospective study using their operation and medical records. Results: A total of 3,869 third molars in 2,697 patients were extracted and the extraction sockets packed with type-I collagen sponges to prevent post-operative complications. As a result, the overall complication rate was 4.52%, with 3.00% experiencing surgical site infection (SSI), 1.14% showing alveolar osteitis, and 0.39% experiencing hematoma. Of the total number of complications, SSI accounted for more than a half at 66.29%. Conclusion: Compared to previous studies, this study showed a relatively low incidence of complications. The use of type-I collagen sponges is recommended for the prevention of complications after third molar extraction.