• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.42 no.2
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• pp.123-126
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• 2016

Dentigerous cysts are common odontogenic cysts that are associated with the crown of the tooth and typically develop from single lesions. Bilateral and multiple dentigerous cysts are very rare and occur in patients with syndromic conditions. This paper presents a case report of a 15-year-old male patient that experienced non-syndromic bilateral dentigerous cysts that simultaneously occurred in all four dental quadrants around the unerupted third molars. Clinicians should confirm the extent of cystic lesions using a panoramic view and computed tomography, and should keep the possibility of bilateral dentigerous cysts in mind as a potential diagnosis, even in a non-syndromic patient.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.12 no.2
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• pp.1-8
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• 1990

Odontogenic cyst has been reviewed with a report on the 193 cases clinico-statistically. We found that cysts occur frequently at third decade male as 29% and second decade female as 30%. Maxilla is more prevalent site as 74.6% than mandible. Uper incisors and lower third molars are the most prebalant teeth. Swelling is the most frequent chief complaint. After enucleating, we grafted to the cystic cavities in 10 cases.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.2
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• pp.59-65
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• 2015

The extraction of third molars is a common task carried out at dental/surgery clinics. Postoperative pain is one of the two most common complications of this surgery, along with dry socket. Knowledge of the frequent risk factors of this complication is useful in determining high-risk patients, planning treatment, and preparing the patients mentally. Since the risk factors for postoperative pain have never been summarized before while the risk factors for dry socket have been highly debated, this report summarizes the literature regarding the common predictors of postextraction pain. Except for surgical difficulty and the surgeon's experience, the influences of other risk factors (age, gender and oral contraceptive use) were rather inconclusive. The case of a female gender or oral contraceptive effect might mainly be associated with estrogen levels (when it comes to dry socket), which can differ considerably from case to case. Improvement in and unification of statistical and diagnostic methods seem necessary. In addition, each risk factor was actually a combination of various independent variables, which should instead be targeted in more comprehensive studies.

• Restorative Dentistry and Endodontics
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• v.14 no.1
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• pp.189-197
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• 1989

The purpose of this study was to observe the resulting canal shape after using hand, sonic and ultrasonic instrumentation. Thirty canals from extracted human upper or lower 1st and 2nd molars were divided into 3 groups: hand, sonic and ultrasonic instrumentation group. 10 canals of each group were individually prepared with one of three instrumentation methods. After instrumentation and histological processing, apical, middle and coronal third cross sections were examined on the roundness of the canal by microscope. The result were as follows. 1. All experimented groups showed no significant difference in canal roundness regardless of size and level of the canal. 2. Sonic air instrumentation groups revealed Significantly better canal roundness than ultrasonic groups at the middle third of the fine canal. 3. In ultrasonic instrumentation groups, the roundness of the large canal was significantly better than that of fine canal.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.11 no.1
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• pp.51-58
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• 1981

The author examined 515 full mouth roentgenograms stored in the Dept. of Oral Radiology, College of Dentistry, Seoul National University. For evaluating the efficiency of the routine full mouth roentgenogram, each of abnormal conditions such as impacted teeth, missing, caries, crown, filling and apical lesions was observed. The results obtained were as follows; 1. Among 14.420 teeth examined, missing teeth were 174, impacted 16, caries 161 and treated 1,162. 2. The incidence of impacted third molar was close to 18.7 percent and the incidence of missing third molar was about 33.4 percent. 3. Among carious and treated teeth, 178 teeth (1.2%) were needed observation of root apex. And of these teeth, 119 teeth 0.8% were observed with apical lesion. 4. There is a considerable relation between the incidence or size of apical lesion and the accuracy of endodontical treat. 5. Among the teeth with apical lesion, upper and lower first molars were most frequent (about 41%), upper and lower canine were rare (about 1.7%).

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.34 no.6
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• pp.640-643
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• 2008

Distal caries of the second molar is common indication for the mandibular third molar surgery and there are no universally acceptable predictive criteria for distal caries of the second molar. To analyze the correlation of the distal caries of the second molar and the eruption state of the mandibular third molar using panoramic radiographs statistically and propose the acceptable guideline for preventive extraction of the mandibular third molar. 786 patients who were extracted the mandibular third molar from 2002 to 2006 at Samsung medical center were examined. The presence and absence of distal caries of mandibular second molar, age, gender, angulation, impaction degree, distance between distal cementoenamel junction of the second molar and mesial cementoenamel junction of the mandibular third molar were assessed. 79.6% of third molars had a mesial angulation of between $40^{\circ}$ and $80^{\circ}$. The mean age of third molar removal for distal caries of second molar was $33.86{\pm}9.81$. The prophylactic removal of a mesio-angular third molar about $40^{\circ}$ and $80^{\circ}$ could prevent distal cervical caries forming in the mandibular second molar.

• Journal of Oral Medicine and Pain
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• v.16 no.1
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• pp.121-136
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• 1991

This study was undertaken to obtain the data for age determination following the calcification degree of the second molar, third molar in the point of forensic odontology. The intraoral panoramic radiograph of 1600 male and 1600 female (100 persons each age) ranging from 7 to 2 years of age were studied. The developmental state of the second molar and third molar were divided into 12 stages following the calcification degree and correlations of second molar developmental stage and statistically analyzed. The results were as follows : 1. There was remarkable correlation between the development of the second molar, the third molar and age. 2. There was no significant developmental differences between the right and left second molar, third molar.(p>0.05) 3. The developmental stages of the lower second molar was more advanced than those of upper second molar. (p<0.05) 4. The developmental stages of upper third molar was more advanced than those of lower third molar. (p<0.05) 5. Both the developmental stages of second, third molars were earlier in the female than in the male. (p<0.001) 6. For the purpose of age estimation according to developmental stages of the second, third molar, linear equations are as follows. (p<0.001) second molar : male upper : Y=1.3927X + 0.2213 (r=0.72) lower : Y=1.4132X + 0.0012 (r=0.78) female upper : Y=1.4914X + 0.2151 (r=0.73) lower : Y=1.5429X - 0.0911 (r=0.78)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.40 no.6
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• pp.278-284
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• 2014

Objectives: This study used cone-beam computed tomography (CBCT) images to categorize the relationships between the mandibular canal and the roots and investigated the prevalence of nerve damage. Materials and Methods: Through CBCT images, contact and three-dimensional positional relationships between the roots of the mandibular third molar and the mandibular canal were investigated. With this data, prevalence of nerve damage according to the presence of contact and three-dimensional positional relationships was studied. Other factors that affected the prevalence of nerve damage were also investigated. Results: When the mandibular third molar and the mandibular canal were shown to have direct contact in CBCT images, the prevalence of nerve damage was higher than in other cases. Also, in cases where the mandibular canal was horizontally lingual to the mandibular third molar and the mandibular canal was vertically at the cervical level of the mandibular third molar, the prevalence of nerve damage was higher than in opposite cases. The percentage of mandibular canal contact with the roots of the mandibular third molar was higher when the mandibular canal was horizontally lingual to the mandibular third molar. Finally, the prevalence of nerve damage was higher when the diameter of the mandibular canal lumen suddenly decreased at the contact area between the mandibular canal and the roots, as shown in CBCT images. Conclusion: The three-dimensional relationship of the mandibular third molar and the mandibular canal can help predict nerve damage and can guide patient expectations of the possibility and extent of nerve damage.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.41 no.2
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• pp.66-73
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• 2015

Objectives: To assess the validity of the vertical tube-shift method using intraoral periapical radiography (IOPAR) for determining the relationship between the mandibular third molar roots and the inferior alveolar nerve (IAN) canal in comparison with cone-beam computed tomography (CBCT). Materials and Methods: Fifty impacted mandibular third molars were analyzed using the IOPAR vertical tube-shift method and CBCT. The relationship of the IAN canal to the impacted mandibular third molar was recorded as buccal, lingual or in line with the apex and was compared with CBCT findings. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the vertical tube-shift method in depicting the relationship (buccal/lingual/in line with the apex) of the IAN canal to the third molar root apex was calculated. Results: The sensitivity and specificity PPV and NPV of the IOPAR vertical tube-shift technique was found to be highest for a lingual relationship (100%) followed by buccal (94.4%, 92.3%, 97.1%, and 85.7%) and in line with the apex relationship (88.9%, 95.0%, 80.0%, and 97.4%) of the IAN canal with the third molar root apex, respectively. A statistically significant association was observed between the IOPAR vertical tube-shift method and the CBCT with a P-value <0.01. Conclusion: The vertical tube-shift method can be used as an effective diagnostic tool in assessing the relationship of the IAN canal to the third molar root apex with high sensitivity, specificity, PPV, and NPV.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.6
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• pp.371-381
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• 2022

Objectives: This study determined the effect of platelet-rich fibrin (PRF) on extraction socket bone regeneration and assessed the patterns and determinants of bone regeneration after the surgical extraction of impacted mandibular third molars. Materials and Methods: This prospective study randomly allocated 90 patients into two treatment groups: A PRF group (intervention group) and a non-PRF group (control group). After surgical extractions, the PRF group had PRF placed in the extraction socket and the socket was sutured, while the socket was only sutured in the non-PRF group. At postoperative weeks 1, 4, 8, and 12, periapical radiographs were obtained and HLImage software was used to determine the region of newly formed bone (RNFB) and the pattern of bone formation. The determinants of bone regeneration were assessed. Statistical significance was set at P<0.05. Results: The percentage RNFB (RNFB%) was not significantly higher in the PRF group when compared with the non-PRF group at postoperative weeks 1, 4, 8, and 12 (P=0.188, 0.155, 0.132, and 0.219, respectively). Within the non-PRF group, the middle third consistently exhibited the highest bone formation while the least amount of bone formation was consistently observed in the cervical third. In the PRF group, the middle third had the highest bone formation, while bone formation at the apical third was smaller compared to the cervical third at the 8th week with this difference widening at the 12th week. The sex of the patient, type of impaction, and duration of surgery was significantly associated with percentage bone formation (P=0.041, 0.043, and 0.018, respectively). Conclusion: Placement of PRF in extraction sockets increased socket bone regeneration. However, this finding was not statistically significant. The patient's sex, type of impaction, and duration of surgery significantly influenced the percentage of bone formation.