• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.2
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• pp.100-105
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• 2017

Objectives: Localization of the mandibular canal (MC) and measurement of the height and width of the available alveolar bone at the proposed implant site in the posterior segment of the mandible using cone-beam computed tomography (CBCT) in patients with a single missing tooth. Materials and Methods: A cross-sectional study was performed where CBCT scans of the patients with a single missing tooth in the posterior segment of the mandible-premolar, I (1st) molar, and II (2nd) molar were used. The scans were assessed using OnDemand3D software (version 1.0; CyberMed Inc., Seoul, Korea) for localization of the MC asnd remaining alveolar bone both vertically (from the superior position of the MC to the crest of the alveolar ridge) and horizontally (buccolingual, 3 mm below the crest of the alveolar ridge). The findings were statistically analyzed using independent t-test. Results: A total of 120 mandibular sites (40 sites for each of the three missing premolar, I molar, and II molar) from 91 CBCT scans were analyzed. The average heights (from the alveolar crest to the superior margin of the MC) at the premolar, I molar, and II molar areas were $15.19{\pm}2.12mm$, $14.53{\pm}2.34mm$, and $14.21{\pm}2.23mm$, respectively. The average widths, measured 3 mm below the crest of the alveolar ridge, at the premolar, I molar, and II molar areas were $6.22{\pm}1.96mm$, $6.51{\pm}1.75mm$, and $7.60{\pm}2.08mm$, respectively. There was no statistically significant difference between males and females regarding the vertical and horizontal measurements of the alveolar ridges. Conclusion: In the study, the measurements were averaged separately for each of the single missing teeth (premolar, I molar, or II molar), giving more accurate information for dental implant placement.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.2
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• pp.70-76
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• 2017

The purpose of this study was to perform a literature review of short implants in the posterior maxilla and to assess the influence of different factors on implant success rate. A comprehensive search was conducted to retrieve articles published from 2004 to 2015 using short dental implants with lengths less than 10 mm in the posterior maxilla with at least one year of follow-up. Twenty-four of 253 papers were selected, reviewed, and produced the following results. (1) The initial survival rate of short implants in the posterior maxilla was not related to implant width, surface, or design; however, the cumulative success rate of rough-surface short implants was higher than that of machined-surface implants especially in performance of edentulous dental implants of length <7 mm. (2) While bone augmentation can be used for rehabilitation of the atrophic posterior maxilla, short dental implants may be an alternative approach with fewer biological complications. (3) The increased crown-to-implant (C/I) ratio and occlusal table (OT) values in short dental implants with favorable occlusal loading do not seem to cause peri-implant bone loss. Higher C/I ratio does not produce any negative influence on implant success. (4) Some approaches that decrease the stress in posterior short implants use an implant designed to increase bone-implant contact surface area, providing the patient with a mutually protected or canine guidance occlusion and splinting implants together with no cantilever load. The survival rate of short implants in the posterior edentulous maxilla is high, and applying short implants under strict clinical protocols seems to be a safe and predictable technique.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.3
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• pp.160-165
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• 2017

Objectives: Dry socket may occur secondary to the removal of any tooth. However, most dry socket cases develop in the third molar region. Dry socket is multifactorial in nature and has been treated using various modalities with varying success rates. This study assessed the efficacy of platelet rich fibrin (PRF) in established dry socket. Materials and Methods: Ten patients of either sex aged from 41 to 64 years with established dry socket according to established criteria were treated using PRF. Evaluation was performed by observing the reduction of pain using visual analogue scale, analgesic tablet use over the follow-up period, and healing parameters. Results: Pain was reduced on the first day in all patients with decreased analgesic use. Pain was drastically reduced during follow-up on the first, second, third, and seventh days with a fall in pain score of 0 to 1 after the first day alone. The pain scores of all patients decreased to 1 by the first day except in one patient, and the scores decreased to 0 in all patients after 48 hours. Total analgesic intake ranged from 2 to 6 tablets (aceclofenac 100 mg per tablet) over the follow-up period of 7 days. Healing was satisfactory in all patients by the end of the seventh day. Conclusion: PRF showed early pain reduction in established dry socket with minimal analgesic intake. No patients had allergic reactions to PRF as it is derived from the patient's own blood. PRF showed good wound healing. Our study suggests that PRF should be considered as a treatment modality for established dry socket.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.3
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• pp.166-170
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• 2017

Objectives: To define the risk of occult cervical metastasis of maxillary squamous cell carcinoma (SCC) and the therapeutic value of elective neck dissection (END) in survival of clinically negative neck node (cN0) patients. Materials and Methods: Sixty-seven patients with maxillary SCC and cN0 neck were analyzed retrospectively, including 35 patients with maxillary gingiva and 32 patients with maxillary sinus. Results: Of 67 patients, 10 patients (14.9%) had occult cervical metastasis. The incidence of occult cervical metastasis of maxillary gingival SCC was higher than that of maxillary sinus SCC (17.1% and 12.5%, respectively). The 5-year overall survival rate was 51.9% for the END group and 74.0% for the non-END group. The success rate of treatment for regional recurrence was high at 71.4%, whereas that for local or locoregional recurrence was low (33.3% and 0%, respectively). Conclusion: The incidence of occult cervical metastasis of maxillary SCC was not high enough to recommend END. For survival of cN0 patients, local control of the primary tumor is more important than modality of neck management. Observation of cN0 neck is recommended when early detection of regional recurrence is possible irrespective of the site or T stage. The key enabler of early detection is patient education with periodic follow-up.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.3
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• pp.186-190
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• 2017

A surgical approach involving the retromolar trigone, posterolateral maxilla, and pterygoid region is the most challenging in the field of maxillofacial surgery. The upper cheek flap (Weber-Ferguson incision) with subciliary extension and the maxillary swing approach have been considered as alternatives; however, neither approach provides sufficient exposure of the pterygoid region and the anterior portion of the mandibular ramus. In this report, we describe two cases in which a lower cheek flap approach was used for complete tumor resection in the retromolar trigone and the anterior mandibular ramus. This approach allows full exposure of the posterolateral maxilla and the pterygoid region as well as the retromolar trigone without causing major sensory disturbances to the lower lip. A mental nerve anastomosis after tumor resection was performed in one patient and resulted in approximately 90% sensory recovery in the lower lip. The lower cheek flap approach provides adequate exposure of the posterolateral maxilla, including the pterygoid, retromolar trigone, and mandibular ramus areas. If the mental nerve can be anastomosed during flap approximation, postoperative sensory disturbances to the lower lip can be minimized.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.3
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• pp.147-151
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• 2017

Objectives: The purpose of this study was to evaluate and compare the treatment outcomes of partial glossectomy with or without elective neck dissection in patients with tongue squamous cell carcinoma (SCCa). Materials and Methods: A total of 98 patients who were diagnosed with tongue SCCa and underwent partial glossectomy between 2005 and 2014 were evaluated. Only 14 patients received elective neck dissection, and 84 patients received only partial glossectomy. Results: There were 56 men and 42 women with a mean age of 57 years and mean follow-up period of 33.7 months. There were 70 patients graded as T1 and 28 as T2. The total occult metastasis rate was 17.3%. The 5-year overall survival rate was 83.3% with elective neck dissection and 92.4% with observation. The 5-year disease-free survival rate was in 70.7% in the elective neck dissection group and 65.3% in the observation group. Conclusion: We retrospectively reviewed the records of 98 patients with tongue SCCa. These patients were divided into two groups, those who underwent elective neck dissection and those who did not. There was no statistically significant difference between the groups undergoing partial glossectomy with or without elective neck dissection.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.182-190
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• 2018

Objectives: Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide. Inconsistency in various histopathologic features for predicting nodal metastasis and overall prognosis and a better understanding of molecular mechanisms of tumourigenesis have shifted the focus to a search for more definitive predictive markers. To identify the role of two immunohistochemical (IHC) markers, E-cadherin and cyclin D1, as predictive markers of aggressiveness in HNSCC and to assess clonal expansion of tumour cells. Materials and Methods: A total of 66 cases of HNSCC with neck node dissection were studied. IHC was performed on primary tumour sections and lymph nodes showing metastatic deposits. Histopathological parameters such as tumour grade and TNM stage together with nodal status were compared according to expression of the two markers. Fischer's chi-square test was used to assess the correlation between the two markers and histopathological parameters. Results: Out of 66 cases studied, 37 showed LN metastasis. Most of the patients were male, and the most common tumour site was buccal mucosa. We found a significant association between loss of E-cadherin and node metastasis (P<0.001) and higher TNM stage (P<0.001). Cyclin D1 overexpression was significantly associated with only nodal metastasis (P=0.007). No significant association with tumour grade was found for either marker. The subgroup of E-cadherin loss with cyclin D1 overexpression was associated with the maximum incidence of nodal metastasis and higher TNM stage, highlighting the importance of using a combination of these two markers. A significant association was noted between the expression of markers at the primary site and at nodal deposits, indicating clonal expansion. Conclusion: A combination of the two markers E-cadherin and cyclin D1 can predict prognosis in HNSCC, although tumour heterogeneity may affect this association in some cases.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.174-181
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• 2018

Objectives: The number of patients with medication-related osteonecrosis of the jaw (MRONJ) is increasing, but treatment remains controversial. Published papers and systematic reviews have suggested that surgical treatment is effective in patients with MRONJ. The purpose of this study was to determine whether preoperative University of Connecticut Osteonecrosis Numerical Scale (UCONNS), other serologic biomarkers, and size of necrosis are prognostic factors for outcome of surgical treatment in MRONJ. Materials and Methods: From January 2008 to December 2016, 65 patients diagnosed with MRONJ at the Department of Oral and Maxillofacial Surgery in College of Dentistry, Dankook University who required hospitalization and surgical treatment were investigated. Patient information, systemic factors, and UCONNS were investigated. In addition, several serologic values were examined through blood tests one week before surgery. The size of osteolysis was measured by panoramic view and cone-beam computed tomography in all patients. With this information, multivariate logistic regression analysis with backward elimination was used to examine factors affecting postoperative outcome. Results: In multivariate logistic analysis, higher UCONNS, higher C-reactive protein (CRP), larger size of osteolysis, and lower serum alkaline phosphate were associated with higher incidence of incomplete recovery after operation. This shows that UCONNS, CRP, serum alkaline phosphate, and size of osteolysis were statistically significant as factors for predicting postoperative prognosis. Conclusion: This study demonstrated that CRP, UCONNS, serum alkaline phosphate, and size of osteolysis were statistically significant factors in predicting the prognosis of surgical outcome of MRONJ. Among these factors, UCONNS can predict the prognosis of MRONJ surgery as a scale that includes various influencing factors, and UCONNS should be used first as a predictor. More aggressive surgical treatment and more definite surgical margins are needed when the prognosis is poor.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.159-166
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• 2018

Objectives: The aim of the study was to compare wound healing complications following the use of either absorbable or non-absorbable sutures for skin closure in cleft lip repair. Materials and Methods: This was a randomized controlled trial conducted at the Department of Oral and Maxillofacial Surgery, Lagos University Teaching Hospital, Idi Araba, Lagos State, Nigeria. Sixty subjects who required either primary or secondary cleft lip repair and satisfied all the inclusion criteria were recruited and randomized into two groups (Vicryl group or Nylon group). The surgical wounds in all subjects were examined on 3rd, 7th, and 14th postoperative days (POD) for presence or absence of tissue reactivity, wound dehiscence, and local wound infection. Results: Hemorrhage, tissue reactivity, wound dehiscence, and local wound infection were identified as wound healing complications following cleft lip repair. The incidence of postoperative wound healing complications on POD3 was 33.3%. Tissue reactivity was more common throughout the evaluation period with the use of an absorbable (Vicryl) suture compared to a non-absorbable (Nylon) suture, although the difference was statistically significant only on POD7 (P=0.002). There were no significant differences in the incidences of wound dehiscence and infection between the two groups throughout the observation period. Conclusion: There were no statistically significant differences in the incidences of wound dehiscence and surgical site wound infection following the use of either Vicryl or Nylon for skin closure during cleft lip repair. However, more cases of tissue reactivity were recorded in the Vicryl group than in the Nylon group on POD7. Particular attention must be paid to detect the occurrence of wound healing complications, most especially tissue reactivity, whenever a Vicryl suture is used for skin closure in cleft lip repair.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.44 no.4
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• pp.167-173
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• 2018

Objectives: Classification of the degree of postoperative nerve damage according to contact with the mandibular canal and buccal cortical bone has been studied, but there is a lack of research on the difference in postoperative courses according to contact with buccal cortical bone. In this study, we divided patients into groups according to contact between the mandibular canal and the buccal cortical bone, and we compared the position of the mandibular canal in the second and first molar areas. Materials and Methods: Class III patients who visited the Dankook University Dental Hospital were included in this study. The following measurements were made at the second and first molar positions: (1) length between the outer margin of the mandibular canal and the buccal cortical margin (a); (2) mandibular thickness at the same level (b); (3) Buccolingual $ratio=(a)/(b){\times}100$; and (4) length between the inferior margin of the mandibular canal and the inferior cortical margin. Results: The distances from the canal to the buccal bone and from the canal to the inferior bone and mandibular thickness were significantly larger in Group II than in Group I. The buccolingual ratio of the canal was larger in Group II in the second molar region. Conclusion: If mandibular canal is in contact with the buccal cortical bone, the canal will run closer to the buccal bone and the inferior border of the mandible in the second and first molar regions.