Seo-Young An

p-Coumaric acid, a constituent of Sasa quelpaertensis Nakai, inhibits cellular melanogenesis stimulated by α-melanocyte stimulating hormone

Background  Recent study has demonstrated that Sasa quelpaertensis (Korean name, Jeju‐Joritdae) extracts inhibit cellular melanogenesis implicating potential use in the control of skin pigmentation.

Odontoma: a retrospective study of 73 cases

Purpose The purpose of the present study was to retrospectively evaluate the clinical findings and treatment results for impacted permanent teeth associated with odontomas. Materials and Methods We retrospectively investigated 73 odontomas in 72 patients who visited Kyungpook National University Dental Hospital from April 2004 through November 2011. The study was performed using medical records, panoramic radiographs, and pathological reports. Data gathered included age, gender, location, chief complaints, effects on dentition, and treatment of odontoma and the impacted tooth associated with odontoma. Results Most compound odontomas (46.7%) were found in the second decade and complex odontomas were not related to age. Odontomas showed no gender predilection. Fifty-five cases (75.3%) of odontomas were detected on routine dental radiographs. Sixty percent of compound odontomas occurred in the canine area and 57.1% of complex odontomas in the molar areas. Impaction of permanent teeth (61.6%) was the most common complication on the adjacent teeth. Most odontomas (84.9%) were removed surgically and impacted permanent teeth were managed by surgical removal (53.2%), orthodontic treatment (25.5%), or surgical repositioning (6.4%). There was a statistically significant relation between age and preservation of the impacted permanent teeth associated with odontomas (p<0.01). Conclusion Early detection and treatment of odontomas increase the possibility of preservation of the impacted tooth. Therefore, it would be suggested that periodic panoramic examination during the first and second decade of life might be beneficial for the early detection and better prognosis of odontomas.

Texture analysis of mandibular cortical bone on digital dental panoramic radiographs for the diagnosis of osteoporosis in Korean women

OBJECTIVE To determine whether individual measurements or a combination of textural features and mandibular cortical width (MCW) derived from digital dental panoramic radiographs (DPRs) are more useful in assessment of osteoporosis. STUDY DESIGN Textural features were obtained by using fractal dimension (FD) and gray-level co-occurrence matrix (GLCM). Digital DPRs and bone mineral densities (BMDs) of the lumbar spine and the femoral neck were obtained from 141 female patients. A naïve Bayes classifier, a k-nearest neighbor (k-NN) algorithm, and a support vector machine were assessed for classifying osteoporosis. RESULTS The combinations of FD plus MCW (95.3%, 92.1%, 96.8%) and GLCM plus MCW (93.7%, 89.5%, 94.2%) for femoral neck BMD showed the highest diagnostic accuracy with the use of the naïve Bayes, k-NN, and support vector machine classifiers, respectively. CONCLUSIONS The combination of textural features and MCW contributed a better assessment of osteoporosis compared with the use of only individual measurements.

Hard and soft tissue changes of osteomyelitis of the jaws on CT images

OBJECTIVES This study aimed to assess the hard and soft tissue changes in osteomyelitis (OM) of the jaws using CT images. STUDY DESIGN The CT images of 153 patients (59 males and 94 females) with OM of the jaws were retrospectively reviewed. The relationships between each space involvement, between space and muscle involvements, between cortical bone defect and space involvement, and between cortical bone defect and muscle involvement were evaluated. RESULTS The cortical bone defect was more common on the buccal side in the maxilla and on the lingual side in the mandible. The most commonly involved muscle was the buccinator muscle in the maxilla and the masseter muscle in the mandible and the most frequently involved space was the buccal space followed by the masticator space. CONCLUSIONS CT is a useful tool in evaluating both hard and soft tissue changes of OM of the jaws.

Accuracy of a direct drill-guiding system with minimal tolerance of surgical instruments used for implant surgery: a prospective clinical study.

PURPOSE A recently introduced direct drill-guiding implant surgery system features minimal tolerance of surgical instruments in the metal sleeve by using shank-modified drills and a sleeve-incorporated stereolithographic guide template. The purpose of this study was to evaluate the accuracy of this new guided surgery system in partially edentulous patients using geometric analyses. MATERIALS AND METHODS For the study, 21 implants were placed in 11 consecutive patients using the direct drill-guiding implant surgery system. The stereolithographic surgical guide was fabricated using cone-beam computed tomography, digital scanning, computer-aided design and computer-assisted manufacturing, and additive manufacturing processes. After surgery, the positional and angular deviations between planned and placed implants were measured at the abutment level using implant-planning software. The Kruskal-Wallis test and Mann-Whitney U test were used to compare the deviations (α=.05). RESULTS The mean horizontal deviations were 0.593 mm (SD 0.238) mesiodistally and 0.691 mm (SD 0.344) buccolingually. The mean vertical deviation was 0.925 mm (SD 0.376) occlusogingivally. The vertical deviation was significantly larger than the horizontal deviation (P=.018). The mean angular deviation was 2.024 degrees (SD 0.942) mesiodistally and 2.390 degrees (SD 1.142) buccolingually. CONCLUSION The direct drill-guiding implant surgery system demonstrates high accuracy in placing implants. Use of the drill shank as the guiding component is an effective way for reducing tolerance.

Radiopacity for Contemporary Luting Cements Using Digital Radiography under Various Exposure Conditions

PURPOSE This study examined the radiopacity of contemporary luting cements using direct digital radiography under a range of exposure conditions. MATERIALS AND METHODS Disc specimens (N = 80, n = 10 per group, ø5 mm × 1 mm) were prepared from 8 resin-based luting cements (BisCem Clearfil SA Luting, Duolink, Maxcem Elite Multilink Speed, Panavia F 2.0, RelyX Unicem Clicker, V-link). The specimens were radiographed using a charge-coupled device sensor along with an 11-step aluminum step wedge (1.5-mm incremental steps) and 1-mm-thick tooth cut using five tube voltage/exposure time setups (60 kVp, 0.10/0.08 seconds; 70 kVp, 0.10/0.08/0.06 seconds) at 4 mA and 30 cm. The radiopacity of the specimens was compared with that of the aluminum step wedge and human enamel and dentin using NIH ImageJ software (available at http://rsb.info.nih.gov/ij/). A linear regression model for the aluminum step wedge was constructed, and the data were analyzed by ANOVA and Duncan post hoc test. RESULTS Maxcem Elite (5.142 to 5.441) showed the highest radiopacity of all materials, followed in order by Multilink Speed (3.731 to 3.396) and V-link (2.763 to 3.103). The radiopacity of Panavia F 2.0 (2.025 to 2.429), BisCem (1.825 to 2.218), Clearfil SA Luting (1.692 to 2.145), Duolink (1.707 to 1.993), and RelyX Unicem Clicker (1.586 to 1.979) were between enamel (2.117 to 2.330) and dentin (1.302 to 1.685). The radiopacity of 70 kVp conditions was higher than that of the 60 kVp conditions. CONCLUSIONS The radiopacities of the tested luting materials were greater than those of dentin or aluminum, satisfying the criteria of the International Organization for Standardization, and they differed significantly from each other in the exposure setups.

Radiopacity of contemporary luting cements using conventional and digital radiography

Purpose This study evaluated the radiopacity of contemporary luting cements using conventional and digital radiography. Materials and Methods Disc specimens (N=24, n=6 per group, ø7 mm×1 mm) were prepared using 4 resin-based luting cements (Duolink, Multilink N, Panavia F 2.0, and U-cem). The specimens were radiographed using films, a complementary metal oxide semiconductor (CMOS) sensor, and a photostimulable phosphor plate (PSP) with a 10-step aluminum step wedge (1 mm incremental steps) and a 1-mm-thick tooth cut. The settings were 70 kVp, 4 mA, and 30 cm, with an exposure time of 0.2 s for the films and 0.1 s for the CMOS sensor and PSP. The films were scanned using a scanner. The radiopacity of the luting cements and tooth was measured using a densitometer for the film and NIH ImageJ software for the images obtained from the CMOS sensor, PSP, and scanned films. The data were analyzed using the Kruskal-Wallis and Mann-Whitney U tests. Results Multilink (3.44–4.33) showed the highest radiopacity, followed by U-cem (1.81–2.88), Panavia F 2.0 (1.51–2.69), and Duolink (1.48–2.59). The R2 values of the optical density of the aluminum step wedge were 0.9923 for the films, 0.9989 for the PSP, 0.9986 for the scanned films, and 0.9266 for the CMOS sensor in the linear regression models. Conclusion The radiopacities of the luting materials were greater than those of aluminum or dentin at the same thickness. PSP is recommended as a detector for radiopacity measurements because of its accuracy and convenience.

Radiographic study of dermal fillers in the facial area: A series of 3 cases

In recent years, as interest in maintaining beauty and a youthful appearance has grown, filler procedures such as soft tissue augmentation have become more popular. These fillers are sometimes seen as radiopaque shadows on radiographic images, either due to the fillers themselves or because of secondary reactions; such findings may present a diagnostic challenge to dentists. The present report describes 3 cases of dermal fillers observed in panoramic and cone-beam computed tomographic (CBCT) images. All 3 elderly female patients had filler injected into their cheeks and chin area for cosmetic purposes decades ago. On panoramic images, multiple symmetric radiopacities were observed in the facial area; on CBCT, these calcifications were seen in the subcutaneous tissue in various shapes and with varying density. In conclusion, dentists should be aware of the imaging characteristics of dermal filler, and should be able to differentiate dermal filler from other pathological findings.

Diagnostic role of cone beam computed tomography for the position of straight array

Abstract Objective: To assess the usefulness of cone beam computed tomography (CBCT) for characterizing electrode insertion and evaluate the influence of electrode insertion status on post-cochlear implantation (CI) outcomes. Design: Twenty-six ears with post-CI CBCT scans were included. The devices were MED-EL Flex28 (n = 21) and Nucleus slim straight (n = 5). The parameters including cochlear duct length (CDL), insertion depth angle (IDA), insertion length of electrode (IL), and cochlear coverage (CC) were analyzed and compared with aided pure-tone threshold (PTA) with implant in free field, and open-set sentence score. Results: The mean CDL was 36.8 ± 1.4 mm. Electrode array was dislocated into scala tympani in two ears. The mean IL and IDA were 26.5 ± 1.9 mm and 541.4 ± 70.2°. The mean linear CC (IL/CDL, 0.73 ± 0.06) was larger than the mean angular CC (IDA/900, 0.60 ± 0.08). The CBCT parameters showed correlation one another. While the aided pure-tone threshold was correlated with IL and IDA, there were no significant correlations in the open-set sentence score. For the postlingually deaf patients with single electrode (Flex 28), the sentence score had no significant correlation and the aided PTA was positively correlated with IL (R = 0.517, p = .028). Conclusions: This study validated the CBCT evaluating the electrode array position. The CBCT could be helpful for the preoperative selection of the optimal array and prediction of the CC.

Verification of a computer-aided replica technique for evaluating prosthesis adaptation using statistical agreement analysis

PURPOSE The purpose of this study was to evaluate the reliability of computer-aided replica technique (CART) by calculating its agreement with the replica technique (RT), using statistical agreement analysis. MATERIALS AND METHODS A prepared metal die and a metal crown were fabricated. The gap between the restoration and abutment was replicated using silicone indicator paste (n = 25). Gap measurements differed in the control (RT) and experimental (CART) groups. In the RT group, the silicone replica was manually sectioned, and the marginal and occlusal gaps were measured using a microscope. In the CART group, the gap was digitized using optical scanning and image superimposition, and the gaps were measured using a software program. The agreement between the measurement techniques was evaluated by using the 95% Bland-Altman limits of agreement and concordance correlation coefficients (CCC). The least acceptable CCC was 0.90. RESULTS The RT and CART groups showed linear association, with a strong positive correlation in gap measurements, but without significant differences. The 95% limits of agreement between the paired gap measurements were 3.84% and 7.08% of the mean. The lower 95% confidence limits of CCC were 0.9676 and 0.9188 for the marginal and occlusal gap measurements, respectively, and the values were greater than the allowed limit. CONCLUSION The CART is a reliable digital approach for evaluating the fit accuracy of fixed dental prostheses.