• The korean journal of orthodontics
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• v.26 no.5 s.58
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• pp.469-485
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• 1996

Orthodontic patients are individuals that grow and develop ; therefore selection of the proper time for orthodontic treatment is considered to be one of most difficult and yet difficult factor. Since the development of cephalometric X-ray, amount and Pattern of craniofacial growth change with aging could be predicted and be came useful in the process of orthodontic treatment. The relationship between the mean values of cephalometric measurements and body height and weight was studied among the groups(boys and girls) of Korean children from the ages 6-years to 17-years. 409 boys and 437 girls with no abnormality in growth and development and no history of orthodontic treatment from the ages of 6 years to 17 years were chosen as subjects Cephaloment X-ray were taken for 3 years and hard tissue analysis based on Burstone's COGS, which was devided into measurements of 6 parts(Cranial base, Maxillar and Mandible, Dental measurements). The relationship between craniofacial growth and height & weight was studied. The following conclusions were obtained : 1. The maximum growth in the measurements of cranial base, N-Ar(FH), N-Ba(FH) corresponded with the age with the maximum increase in body height & weight in both boys and girls. 2. Genial angle gradually decreased with aging in both boys and girls. 3. N-ANS(L) showed greater amount of growth than ANS-Ne(L), and this had greater influence on facial profile. 4. N-A-$Pog^{\circ}$ decreased with aging, and mandibular growth exceeded maxillary growth in amount and rate. 5. Length of Y-axis Increased, but Y-axis to FH plane remained constant. This show that mandible grows at a constant angulation to cranial base. 6. As permanent teeth erupt, interincisal angle deceased.

• The korean journal of orthodontics
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• v.39 no.6
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• pp.362-371
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• 2009

Objective: The purpose of this study was to compare the longitudinal treatment effects of facemask with rapid maxillary expansion (FM/RME) and chincup (CC) therapy followed by fixed orthodontic treatment (FOT) in Class III malocclusion (CIII) patients. Methods: The samples consisted of twenty-one CIII patients who had similar skeletal and dental characteristics before FM/RME or CC therapy and good retention results (Class I molar/canine relationship and positive overbite/overjet) after FOT (Group 1, FM/RME, n = 11; Group 2, CC, n = 10). Lateral cephalograms were taken before (T0) and after FM/RME or CC therapy (T1), and after FOT and retention (T2). Skeletal and dental variables were measured. Mann-Whitney U-test and Wilcoxon signed-rank test were used for statistical analysis. Results: During T0-T1, FM/RME therapy induced forward movement of point A, and labioversion of the upper incisors. Both groups showed posterior repositioning of the mandible. FM/RME resulted in increase of the vertical dimension; however, CC caused an increase in articular angle and decrease in gonial angle. During T1-T2, both groups exhibited forward growth of point A. Group 1 showed forward growth and counterclockwise rotation of the mandible and increase of IMPA; however, Group 2, showed increase of ANS-Me/N-Me and decrease of overbite. Conclusions: The key factor for successful FM/RME and CC therapy and good retention results might be a harmonized forward growth of the maxilla that could keep pace with the growth and rotation of the mandible.

• The korean journal of orthodontics
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• v.39 no.5
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• pp.300-309
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• 2009

Objective: The purpose of this study was to evaluate the correlation between menton deviation and dental compensation in facial asymmetry. Methods: Tooth axis and distance of first molar and canine to the reference plane were investigated by cone-beam computerized tomography. The subjects consisted of 50 patients with asymmetric mandibles (male 21, female 29, mean age 24.3 years). Control groups were also assessed (male 11, female 9, mean age 25.6 years). Nine measurements (5 linear measurements and 4 angular measurements) were measured in order to evaluate the correlation between menton deviation and the linear and angular difference of first molar and canine in the deviated and none-deviated sides using the defined MPR images. The differences between deviated and non-deviated side, according to menton deviation, were statistically analyzed using stepwise multiple regression analysis. Results: From the result, Menton deviation was negatively correlated with mandibular first molar's angular measurement (${\Delta\angle}LM6$-Mn plane (dev.-ndev.)) and positively with maxillary fist molar's angular measurement (${\Delta\angle}UM6$-FH plane (dev.-ndev.)) (p < 0.01). Two angular measurements (${\Delta\angle}LM6$-Mn plane (dev.-ndev.), ${\Delta\angle}UM6$-FH plane (dev.-ndev.)) explained the variability in menton deviation with a significant $r^2$ value of 0.589. Conclusions: This study suggests that the tooth axis of upper and lower first molars leans towards the deviated side of Menton when there is mandibular asymmetry with Menton deviation.

• Restorative Dentistry and Endodontics
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• v.20 no.1
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• pp.328-341
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• 1995

I. Shear Bond Strength to Air-dried and Remoistened Dentin.. The effect of air-drying and remoistening of acid-conditioned dentin before priming with the primer of All-Bond 2(BISCO. INC., U. S. A.) on shear bond strength(SBS) was investigated. Ninty freshly extracted sound human molars were divided at random into 9 groups of 10 teeth each. SBSs were meaured for acid-conditioned and non-conditioned dentin to which the primer and bonding agent of All-Bond 2 and composite resin(Z-100, 3M Dental Products, U. S. A.) were applied. The following values(Mean${\pm}$ SD, MPa) were obtained for the groups conditioned with 10% phosphoric acid for 15 seconds: Group l(blot dried) $6.7{\pm}4.1$ ; Group 2(10 seconds dried) $16.1{\pm}5.3$ ; Group 3(20 seconds dried) $15.4{\pm}4.8$ ; Group 4(30 seconds dried) $15.2{\pm}6.3$ ; Group 5(10 seconds dried/remoistened) $26.4{\pm}2.6$ ; Group 6(20 seconds dired/remositened) $22.2{\pm}2.7$ ; Group 7(30 seconds dried/remoistened) $21.5{\pm}4.1$. For the non-conditioned groups the values were: Group 8 (blot dried) $13.3{\pm}2.6$ ; Group 9(10 seconds dried) $12.9{\pm}3.5$. The data were analyzed using ANOVA. In the acid-conditioned groups, mean values of SBS for the air-dried specimens(Grps. 2, 3 and 4) and the 20 and 30 seconds dried/remoistened specimens (Grps. 6 and 7) were significantly lower than that of blot dried specimens.(p<0.05) The value for 10 seconds dried/remoistened specimens (Grp. 5), however, was not statistically different compared to that of blot dried specimens.(p>0.05) In the non-conditined groups, there was no statistical difference between blot dried and 10 seconds dried specimens.(p>0.05) The results suggest that the acid-conditioned dentin surface is more vulnerable to dentin bonding when it is air-dried or even remoistened after long period of drying. II. Shear bond stengh to the moistened and primed enamel. The effect of moistening and priming of enamel compared to the air-drying of enamel on the shear bond strength of enamel bonding agent was investigated. The experiment was divided into 4 groups each containing 10 caries-free maxillary incisor teeth. Shear bond strength values were measured for the primed and non-primed enamel to which All-Bond 2 and Z-100 were applied. The following values(MPa) were obtained for the primed groups pretreated with 32 % phosphoric acid for 15 seconds. : Group 1 (10 seconds dried) $29.8{\pm}2.2$ ; Group 2(moistened) $26.8{\pm}5.4$. For the non-primed groups the values were: Group 3(10 seconds dried/primed) $27.6{\pm}5.0$ ; Group 4(mostened/primed) $28.2{\pm}3.5$. The data were subjected to statistical analysis using ANOVA. The results showed that mean shear bond strengths among the experimental groups were not statistically different. (p>0.05) Conclusively, It is suggested that the bonding ability to enamel is not decreased by the moistening and priming of the enamel.

• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.188-197
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• 2010

The purpose of this study was to compare radiopacity and radiographic discriminability of various FRC-Posts. Six FRC-Posts were investigated ; 1) FRC Postec Plus (Ivoclar Vivadent AG, Schaan, Liechtenstein), 2) Snowlight (Carbotech, Lewis center, OH, USA), 3) Dentin Post (Komet Brasseler, Lamgo, Germany), 4) Rely-X Fiber Post (3M ESPE, St.paul, MN, USA), 5) D.T.-Light Post (BISCO, Schaumburg, IL,USA), 6) Luxapost (DMG, Hamburg, Germany) The radiographs of each post with a reference 1 mm / 2 mm aluminum step-wedge was taken using digital sensor. The optical density were calculated by gray value of $10{\times}10$ pixel and compared in mm Al equivalent at five points. Six maxillary incisors of similar radiopacity were used. Radiographs of posts in Mx. incisors of lingual side of dry mandible were taken. We showed radiographs and asked the questionnaire to 3 radiologists, 3 endodontists, 3 general practitioners. The questionnaire was comprised of choices of the highest, lowest radiopaque individual post and the choices of best discriminable post at apical, coronal area. The following results were obtained. 1. Each post system showed various radiopacity. 2. There was change of discriminability between each post and simulated specimens regardless of examiner. Although each post showed various radiopacity, the difference of radiopacity did not affect on discriminability.

• Restorative Dentistry and Endodontics
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• v.35 no.4
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• pp.285-294
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• 2010

The purpose of this study was to evaluate the viability of periodontal ligament cells of rat teeth after low-temperature preservation under high pressure by means of MTT assay, WST-1 assay. 12 teeth of Sprague-Dawley white female rats of 4 week-old were used for each group. Both side of the first and second maxillary molars were extracted as atraumatically as possible under tiletamine anesthesia. The experimental groups were group 1 (Immediate extraction), group 2 (Slow freezing under pressure of 3 MPa), group 3 (Slow freezing under pressure of 2 MPa), group 4 (Slow freezing under no additional pressure), group 5 (Rapid freezing in liquid nitrogen under pressure of 2 MPa), group 6 (Rapid freezing in liquid nitrogen under no additional pressure), group 7 (low-temperature preservation at $0^{\circ}C$ under pressure of 2 MPa), group 8 (low-temperature preservation at $0^{\circ}C$ under no additional pressure), group 9 (low-temperature preservation at $-5^{\circ}C$ under pressure of 90 MPa). F-medium and 10% DMSO were used as preservation medium and cryo-protectant. For cryo-preservation groups, thawing was performed in $37^{\circ}C$ water bath, then MTT assay, WST-1 assay were processed. One way ANOVA and Tukey HSD method were performed at the 95% level of confidence. The values of optical density obtained by MTT assay and WST-1 were divided by the values of eosin staining for tissue volume standardization. In both MTT and WST-1 assay, group 7 ($0^{\circ}C$/2 MPa) showed higher viability of periodontal ligament cells than other group (2-6, 8) and this was statistically significant (p < 0.05), but showed lower viability than group 1, immediate extraction group (no statistical significance). By the results of this study, low-temperature preservation at $0^{\circ}C$ under pressure of 2 MPa suggest the possibility for long term preservation of teeth.

• Radiation Oncology Journal
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• v.21 no.2
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• pp.112-117
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• 2003

Purpose: The effects of hypefractionation radiation therapy, such as the failure pattern and survival, on the treatment results in advanced stage head and neck cancer were studied. Materials and Methods: Between September 1990 and October 1998, 24 patients with advanced stage (III, IV) head and neck cancers, were treated using hyperfractionation radiation therapy in the Department of Radiation Oncology at the Keimyung University Dongsan Medical Center. The male to female ratio was 7 : 1, and the age range from 38 to 71 years with the median of 56 years. With regard to the TNM stage, 11 patients were stage III and 13 were stage IV. The sites of primary cancer were the nasopharynx in six, the hypopharynx in 6, the larynx in five, the oropharynx in three, the maxillary sinus in three, and the oral cavity in one patient. The radiotherapy was delivered by 6 MV X-ray, with a fraction size of 1.2 Gy at two fractions a day, with at least 6 hours inter-fractional interval. The mean total radiation doses was 72 Gy, (ranging from 64.4 to 75.8 Gy). Follow-up periods ranged between 3 and 136 months, with the median of 52 months. Results: The overall survival rates at 3 and 5 years in all patients were 66.7$\%$, and 52.4$\%$. The disease-free survival rates at 3 and S years (3YDFS, 5YDFS) in all patients were 66.7$\%$ and 47.6$\%$. The 3YDFS and 5YDFS in stage III patients were 81.8$\%$ and 63.6$\%$, and those in stage IV patients were 53.8$\%$ and 32.3$\%$. Ten patients were alive with no local nor distant failures at the time of analyses. Six patients (25$\%$) died due to distant metastasis and 12.5$\%$ died due to local failure. Distant metastasis was the major cause of failure, but 2 patients died due to unknown failures and 3 of other diseases. The distant metastasis sites were the lung (3 patients), the bone (1 patient), and the liver (2 patients). One patient died of second esophageal cancer. There were no severe late complications, with the exception of 1 osteo-radionecrosis of the mandible 58 months after treatment. Conclusion: Although this study was peformed on small patients group, we considered hypefractionated radiation therapy for the treatment of advanced stage head and neck cancer might improve the disease free survival and decrease the local failure with no increase in late complications despite of the slight Increase in acute complications.

• Radiation Oncology Journal
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• v.25 no.2
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• pp.118-124
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• 2007

[ $\underline{Purpose}$ ]: This study was to evaluate the survival and pattern of failure after radiation therapy of sino-nasal cancer using partial attenuation filer and wedged beams and to help radiotherapy planning of sino-nasal cancer. $\underline{Materials\;and\;Methods}$: Between February 1992 and March 2003, 17 patients with sino-nasal cancers underwent radiation therapy using partial attenuation filter at Dongsan Medical Center, Keimyung university. There were 9 male and 8 female patients. Patients' age ranged from 40 to 75 years (median 59 years). There were 10 patients of maxillary sinus cancer, 7 patiens of nasal cancer. The histologic type was squamous cell carcinoma in 11, adenoid cystic carcinoma in 4 and olfactory neuroblastoma in 2. The distribution of clinical stage by the AJCC system was 3 for stage II, 7 for III and 6 for IV. The five patients were treated with radiation alone and 12 patients were treated with surgery and postoperative radiation therapy. The range of total radiation dose delivered to the primary tumor was from 44 to 76 Gy (median 60 Gy). The follow-up period ranged from 3 to 173 months with median of 78 months. $\underline{Results}$: The overall 2 year survival rate and disease free survival rate was 76.4%. The 5 year and 10 year survival rate were 76.4% and 45.6% and the 5 year and 10 year disease free survival rate was 70.6%. The 5 year disease free survival rate by treatment modality was 91.6% for postoperative radiation group and 20% for radiation alone group, statistical significance was found by treatment modality (p=0.006). There were no differences in survival by pathology and stage. There were local failure in 5 patients (29%) but no distant failure and no severe complication required surgical intervention. $\underline{Conclusion}$: Radiation therapy of sino-nasal cancer using partial attenuation filter was safe and effective. Combined modality with conservative surgery and radiation therapy was more advisable to achieve loco-regional control in sino-nasal cancer. Also we considered high precision radiation therapy with dose escalation and development of multi-modality treatment to improve local control and survival rate in advanced sino-nasal cancer.

• Korean Journal of Head & Neck Oncology
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• v.14 no.2
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• pp.156-163
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• 1998

Background & Objectives: Frameless fractionated stereotactic radiotherapy(FFSRT) is a modification of stereotactic radiosurgery(SRS) with radiobiologic advantage of fractionation without losing mechanical accuracy of SRS. Local recurrence of head and neck cancer at or near skull base benefit from reirradiation. Main barrier to successful palliation is dose limitation secondary to normal tissue tolerance. We try to evaluate the efficacy and safety of FFSRT as a new modality of reirradaton in these challenging patients. Materials & Methods: Seven patients with recurrent head & neck cancer involving at or near skull base received FFSRT from September 1995 to November 1997. Six patients with nasopharyngeal cancer had received induction chemotherapy and curative radiation therapy. One patient with maxillary sinus cancer had received total maxillectomy and postoperative radiation therapy as a initial treatment. Follow-up ranged from 11 to 32 months with median of 24 months. Three of 7 patients received hyperfractionated radiation therapy(1.1-1.2Gy/fraction, bid, total 19.8-24Gy) just before FFSRT. All patients received FFSRT(3-5Gy/fraction, total 15-30Gy/5-10fractions). Chemotherapy(cis-platin $100mg/m^2$) were given concurrently with FFSRT in four patients. Second course of FFSRT were given in 4 patients with progression or recurrence after initial FFSRT. Because IF(irregularity factor; ratio of surface area of target to the surface area of sphere with same volume as a target) is too big to use conventional stereotactic RT using multiple arc method for protection of radiation damage to critical normal tissue, all patients received FFSRT with conformal method using irregular static ports. Results: Five of 7 patients showed complete remission in follow-up CT &/or MRI. Three of these five patients who developed marginal, in-field, and out-field recurrences, respectively. Another one of complete responders has been dead of G-I bleeding without evidence of local recurrence. One partial responder who showed progressive disease 15 months after initial FFSRT has received additional FFSRT, and then he is well-being with symptomatic improvement. One minmal responder who showed progression of locoregional disease 9 months after $1^{st}$ FFSRT has received 2nd FFSRT, and then he is alive with stable disease. Five of 7 case had showed direct invasion to skull base and had complaint headache and various symptoms of cranial nerve involvement. Four of these five case showed improvement of neurologic symptoms after FFSRT. No significant neurologic complicaltion related to FFSRT was observed during follow-up periods. Tumor volumes were ranged from 3.9 to 50.7 cc and surface area ranged from 16.1 to $114.9cm^2$. IF ranged from 1.21 to 1.74. The average ratio of volume of prescription isodose shell to target volume was 1.02 that indicated the improvement of target coverage and dose distribution with FFSRT with conformal method compared to target coverage with FFSRT with multiple arc method. Conclusion: Our initial experience suggests that FFSRT with conformal method was relatively effective and safe modality in the treatment of recurrent head and neck cancer involving at or near skull base. Treatment benefit included good palliation of symptoms and reasonable radiographic response. However, more experience and additional follow-up are needed to better assess its ultimate role in treating these challenging patients.

• Restorative Dentistry and Endodontics
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• v.27 no.2
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• pp.150-157
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• 2002

One of the latest concepts in bonding are "total etch", in which both enamel and dentin are etched with an acid to remove the smear layers, and "wet dentin" in which the dentin is not dry but left moist before application of the bonding primer Ideally the application of a bonding agent to tooth structure should be insensitive to minor contamination from oral fluids. Clinically, contaminations such as saliva, gingival fluid, blood and handpiece lubricant are often encountered by dentists during cavity preparation. The aim of this study was to evaluate the effect of contamination by hemostatic agents on shear bond strength of compomer restorations. One hundred and ten extracted human maxillary and mandibular molar teeth were collected. The teeth were removed soft tissue remnant and debris and stored in physiologic solution until they were used. Small flat area on dentin of the buccal surface were wet ground serially with 400, 800 and 1200 abrasive papers on automatic polishing machine. The teeth were randomly divided into 11 groups. Each group was conditioned as follows : Group 1: Dentin surface was not etched and not contaminated by hemostatic agents. Group 2: Dentin surface was not etched but was contaminated by Astringedent$^{\circledR}$(Ultradent product Inc., Utah, U.S.A.) Group 3: Dentin surface was not etched but was contaminated by Bosmin$^{\circledR}$(Jeil Pharm, Korea.). Group 4: Dentin surface was not etched but was contaminated by Epri-dent$^{\circledR}$(Epr Industries, NJ, U.S.A.). Group 5: Dentin surface was etched and not contaminated by hemostatic agents. Group 6: Dentin sorface was etched and contaminated by Astringedent$^{\circledR}$. Group 7 : Dentin surface was etched and contaminated by Bosmin$^{\circledR}$. Group 8: Dentin surface was etched and contaminated by Epri-dent$^{\circledR}$. Group 9: Dentin surface was contaminated by Astringedent$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. Group 10: Dentin surface was contaminated by Bosmin$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. Group 11 : Dentin surface was contaminated by Epri-dent$^{\circledR}$. The contaminated surface was rinsed by water and dried by compressed air. After surface conditioning, F2000$^{\circledR}$ was applicated on the conditoned dentin surface The teeth were thermocycled in distilled water at 5$^{\circ}C$ and 55$^{\circ}C$ for 1,000 cycles. The samples were placed on the binder with the bonded compomer-dentin interface parallel to the knife-edge shearing rod of the Universal Testing Machine(Zwick Z020, Zwick Co., Germany) running at a cross head speed or 1.0 mm/min. Group 2 showed significant decrease in shear bond strength compared with group 1 and group 6 showed significant decrease in shear bond strength compared with group 5. There were no significant differences in shear bond strength between group 5 and group 9, 10 and 11.