• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.6
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• pp.643-647
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• 2007

Purpose: The purpose of study was to investigate the correlationship between lip canting change and occlusal canting change after bimaxillary orthognathic surgery, and the ratio of lip canting change and occlusal canting change after the surgery. Patients and methods: The subjects for this study was obtained from a group of 25 patients who took bimaxillary orthognathic surgery for occlusal canting correction at the Department of the Oral and Maxillofacial Surgery, Samsung Medical Center in Seoul, Korea between January 2000 and December 2005 and a patient's chart had to contain a resting frontal facial photograph in natural head position and a corresponding PA cephalogram in occlusion on the same day before the surgery and post-op 6 months later. The lip canting change was assessed with the angle each labial commissure and the bipupilary reference line. And, the occlusal caning change in the frontal plane was assessed with the angle between the each maxillary first molar occulasal surface and the bi-frontozygomatic suture reference line. Results: In angular measurement, average occlusal canting change was $3.09^{\circ}$ and standard deviation was $1.05^{\circ}$, average lip canting change was $1.56^{\circ}$ and standard deviation was $1.05^{\circ}$. In linear measurement, average occlusal canting change was 2.41mm and standard deviation was 2.75mm, average lip canting change was 1.18mm and standard deviation was 0.43mm. Lip canting correction ration to occlusal canting correction was 51.5(${\pm}8.4$)% in angular measurement and 48.8(${\pm}9.1$)% in linear measurement. Under Pearson's correlation analysis, Pearson's correlation coefficient was 0.869 in angular measurement and 0.887 in linear measurement(p-value < 0.01). High correlationship was shown between occlusal canting change and lip canting change. Conclusion: First, Bimaxillary orthognathic surgery can correct lip canting as well as occlusal canting. Second, The average amount of lip canting correction is $51.5{\pm}8.4%,\;48.8{\pm}9.1%$ of occlusal canting correction in the study.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.805-824
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• 2007

Purpose: Developments in micro/macrostructures of implants and surgical techniques brought out stable outcomes of implant dentistry. The aim of this study was to evaluate the distributions of implant patients, the types of implanted sites, and the success or survival rates of various implant systems and to analyze the implant placement done at each specificintraoral site and situation. Materials and Methods: The data of dental implantations collected between 1992 and 2006 at the Department of Periodontology in 00000 University Hospital were analyzed. Results: 1. Largest part of the patients were at the age of 40s and 50s in bothgender who lost their teeth mostly by periodontaldiseases and caries at the posterior intraoral sites as major ones. Bone densities of type II(mandible) and III(maxilla) were likely to be seen with quantity of type B. Lengths of the implants between 10 and 15 mm and wide platform took the largest part. 2. Survival rates of $Implantium^{(R)}(98.8%)$, $Xive^{(R)}(100%)$ and ITI $TE^{(R)}(100%)$ were high when $Frialit-2^{(R)}$ showed 82%(poor bone density area) or 87.2%(combined with additional therapy). $IMZ^{(R)}$ had lowest cumulative survival(67.5%) and success rate(49.4%) amongst all. 3. Replacement with 2 wide or 3 regular platforms showed no significant differences in survival rate and marginal bone loss atmandibular posterior area. In single restoration of mandibular second molar, 5-year success rate of machined surface $Br{\aa}nemark^{(R)}(70.37%)$ was lower than that of rough surface $ITI^{(R)}$ SLA(100%). 4. Replacement of single tooth in anterior area showed high survival rate of 94.5%. 5. The success rates of $Br{\aa}nemark$ Ti-Unite and ITI SLA at posterior maxilla with poor bone density both showed stable outcomes. 6. 10-year cumulative survival rate of implants with maxillary sinus augmentation by lateral window approach appeared to be 96.60%. Low survival rate(75%) was shown when there were more than two complications combined. Height of grafted bone remained stable above the implant apex. Conclusions : Rough surfaced implants showed stable outcomes in most of the situation including poor bone density and additional therapy combined.

• Journal of dental hygiene science
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• v.6 no.1
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• pp.29-34
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• 2006

This study was undertaken to compare the tooth and arch size between crowding patient and normal subjects. Two group of dental casts were selected on the basis of crowding patients and normal subjects. One group, consisting of 40 pair of dental casts(20 male and 20 female), exhibited noncrowded dentitions. A second group, consisting of 40 pairs of dental cast(21 male and 21 female), exhibited remarkably crowding need for orthodontic treatment. Tooth width measurements were made with a sliding digital caliper with Vernier scale neared 0.01 mm. Mean, standard deviation, T-test of the following parameters were used to compare two group : individual mesiodistal crown widths, arch width and arch length. The following result were obtained. In the mesiodistal crown widths, normal subjects had generalized larger teeth than Wheeler's results(human tooth size index), except for maxillary central incisor, maxillary 2nd premolar, mandibular canine, and mandibular 1st molar. In the orthodontic patients with crowded dentitions, the mesiodistal tooth crown widths were generalized larger teeth than noncrowded normal subjects. In the arch width and arch length, the crowded dentition group had smaller arch width and arch length than the normal group.

• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.37-46
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• 2007

The C-shaped canal system is an anatomical variation mostly seen in mandibular second molars, although it can also occur in maxillary and other mandibular molars. The main anatomical feature of C-shaped canals is the presence of fins or web connecting the individual root canals. The complexity of C-shaped canals prevents these canals from being cleaned, shaped, and obturated effectively during root canal therapy, and sometimes it leads to an iatrogenic perforation from the extravagant preparation. The purpose of this study was to provide further knowledge of the anatomical configuration and the minimal thickness of dentinal wall according to the level of the root. Thirty extracted mandibular second molars with fused roots and longitudinal grooves on lingual or buccal surface of the root were collected from a native Korean population. The photo images and radiographs from buccal, lingual, apical direction were taken. After access cavity was prepared, teeth were placed in 5.25% sodium hypochlorite solution for 2 hours to dissolve the organic tissue of the root surface and from the root canal system. After bench dried and all the teeth were embedded in a self-curing resin. Each block was sectioned using a microtome (Accutom-50, Struers, Denmark) at interval of 1 mm. The sectioned surface photograph was taken using a digital camera (Coolpix 995, Nikon, Japan) connected to the microscope. 197 images were evaluated for canal configurations and the minimal thickness of dentinal wall between canal and external wall using 'Root Thickness Gauge Program' designed with Visual Basic. The results were as follows : 1. At the orifice level of all teeth, the most frequent observed configuration was Melton's Type C I (73%), however the patterns were changed to type C II and C III when the sections were observed at the apical third. On the other hand, the type C III was observed at the orifice level of only 2 teeth but this type could be seen at apical region of the rest of the teeth. 2. The C-shaped canal showed continuous and semi-colon shape at the orifice level, but at the apical portion of the canal there was high possibility of having 2 or 3 canals 3. Lingual wall was thinner than buccal wall at coronal, middle, apical thirds of root but there was no statistical differences.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.441-452
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• 1998

The c-fos is known as neuronal marker of second neurons which is activated by noxious peripheral stimulation. To investigate the changes of c-fos el(pression in the trigeminal nucleus complex during tooth movement, immunohistochemical study was performed. Experimental rats(9 weeks old, 210 gm 21 rats) were divided into seven groups(normal, 1 hour group, 3 hour group, 6 hour group, 12 hour group, 1 day group,3 day group). Rats in the normal group were anesthesized without orthodontic force. Rats in the experimental groups were applied orthodontic force (approximately 30 gm) to upper right maxillary molar. Frozen sections of brain stem were immunostained using rabbit antisera. The changes of c-fos expression were observed with respect to rostrocaudal distribution, laminar organization, md duration of orthodontic force application. The study results were as follows $\cdot$The c-fos nuclei in the dorsal part were observed from ipsilateral transition zone of subnucleus interpolaris and subnucleus caudalis to $C_1$ cervical dorsal horn rostrocaudally. The maximal peak point was the rostral part of subnucleus caudalis. The greatest proportion of c-fos cells were located within lamina I and II. $\cdot$The c-fos nuclei in the dorsal Part were observed from the most caudal part of subnucleus interpolaris to the middle part of the subnucleus caudalis. $\cdot$The number of c-fos immunoreactive dot increased at 1 hour group, reached its maximum at the 3 and 6 hour groups, and showed a decreasing trend after 12 hours. These results imply that nociceptive stimulation caused by continuous orthodontic force might be modulated by transition zone of subnucleus interpolaris and subnucleus caudalis, subnucleus caudalis, $C_1$ spinal dorsal hem.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.398-408
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• 2006

The purpose of this study was to verify the usefulness of MTT analysis as a tool of measurement of the periodontal ligament cell viability from the extracted rat molar. A total of 80 Sprague-Dawley white female rat of 4 week-old with a body weight of 100 grams were used. The maxillary left and right, first and second molars were extracted under Ketamine anesthesia. Twenty-four teeth of each group (divided as five groups depending upon the time-lapse after extraction such as Immediate, 10, 20, 40 and 60 minutes) were immersed in $200{\mu}l$ of MTT solution (0.5 mg/ml) and processed for optical density measurements. Another 10 teeth of each group were treated as same as above and sectioned at $10{\mu}m$ for microscopic examination. All measurements values were divided by the value of hematoxylin-eosin staining which represented the volume of each corresponding samples. Immediate and 10 minute groups showed highest MTT values followed by 20, 40, and 60 minutes consecutively. Statistical significance (p<0.05) existed between all groups except in immediate versus 10 minute groups and 40 versus 60 minutes. Histological findings also showed similar findings with MTT results in crystal shape and crystal numbers between the experimental groups. These data indicate that in vivo MTT analysis nay be of value for evaluation of the periodontal ligament cell viability without time- consuming cell culturing processes.