• Journal of Oral Medicine and Pain
• /
• v.33 no.2
• /
• pp.167-176
• /
• 2008

We analyzed 121 age estimation clients who had visited oral medicine clinic, Chonbuk National University Hospital, from January 2000 to December 2007 to evaluate its characters in Jeonllabuk-do. The obtained results were as follows : 1. There was distinct difference in sex distribution(Male : 58.7%, Female : 41.3%) and more than half percent(55.4%) was over 50's. 2. The difference between registered and alleged age was the most in more than 5 years, and most of them were over 50's. 3. There were more clients who wanted to increase their age than to decrease and was no prominent difference in sex. Age estimation clients who wanted to decrease their age were predominant under 10 years old and in 20's, and those wanted to increase were predominant in 10's and over 30's. 4. The most reasons to correct age were related to welfare benefit. The purpose of age estimation was different according to each age groups; welfare benefit was the most over 50's, occupation in 40's and 50's, friendship in 30's and 40's, sibling-related in 50's, employment in 10's and 20's. 5. Age was estimated by the attrition of permanent tooth and pulp/tooth ratio from 20 years, root apex closure for 10's and calcification of permanent tooth under 10 years old. In cases that were difficult to estimate by use of the attrition of permanent tooth and pulp/tooth ratio, age was estimated by missing time of permanent tooth and the change of mandibular angle with age. 6. The estimated ages were close to alleged age in 77.7% of clients but the rest(22.3%) was close to registered age.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.5
• /
• pp.497-506
• /
• 2000

This study is comprised of data obtained from the files of 346 patients with temporomandibular disorders. All patients were diagnosed, treated and followed in the Department of Dentistry at the Inha university hospital, Incheon, Korea. The patients had treated with medications, physical therapy, occlusal splint and arthrocentesis. The study data were obtained from the medical records and telephone interviews that were conducted by research assistants. The results were as follows 1. The patient's main complaint was pain(77%), and mouth opening limitation was 17%. 2. An analysis of the medical records of the 346 patients disclosed that 82% were improved and 17% had no improvement when they were dismissed. 1% of the patients had become worse during therapy. 3. A success rate of 82% was achieved when medication assisted physical therapy was included. In the current status at the telephone interview, 270 patients(89%) reported that they were doing well with 56% describing themselves as asymtomatic and 32% experiencing only minor residual or recurrent symptoms. 11% regarded themselves as unimproved and worse. 4. In the current status of the unsuccessfully treated patients by medications and physical therapy, 64% of patients were doing well(3% as asymptomatic and 56% as only minor residual or recurrent symptom). But 36% of patients was reported as unimproved and worse. 5. TMJ has a remarkable adaptive potential and TMJ disorder has a natural history of spontaneous fluctuations and favorable prognosis during the subsequent natural course. 6. In the treatment of the temporomandibular disorders, there is a treatment ladder, starting with the simplest and least expensive treatment, that is ascended until resolution of the patient's symptoms occur. These findings suggest that conservative reversible therapies are both sufficient and appropriate for management of temporomandibular disorder in most patients. Major alterations of mandibular position or dentoalveolar relationships do not appear to be necessary for obtaining either short term or long term success and therefore they can be generally regards as inappropriate treatment for this disorder. The fact that physical therapy is non-invasive and does not appear to be fraught with irreversible changes, makes it a very applicable vehicle in the area of clinical TMJ disorder management.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.26 no.6
• /
• pp.628-635
• /
• 2000

The purpose of this study was to evaluate the result after 2-phase surgical-orthodontic treatment without preoperative orthodontic treatment for the skeletal Cl III malocclusion patient and to obtain an adequate protocol on the bases of this result. This retrospective study of ten patients who underwent 2-phase treatment were done to evaluate 1) the surgical stability and relapse pattern 2) the facial esthetics 3) the TMJ problem 4) the total time of the treatment. Results were followed : 1) The horizontal relapse of the mandible was 26.8% and didn't show significant differences compared to the conventional 3-phase treatment. But, it was considered that this amount of relapse was the sum of true relapse and autoratation of mandible due to decreased vertical dimension during orthodontic treatment. 2) It was estimated that there's no difference on the ratio of anterior facial height between the subjects and the normal patients. On the horizontal analysis, the mandible of the subjects was located more anteriorly than that of the normal patients. This result showed that there was a need for the accurate preoperative esthetic evaluation and the additional methods for reducing the relapse due to the occlusal interference. 3) Wide variation was noted on the TMJ symptoms of the subjects, however, it was estimated that there's no significant differencees of symptoms compared to that of the conventional 3-phase treatment on literatures. 4) The average of the overall period of treatment was 20.8 months and we obtained reduction of the treatment time compaired to 3-phase treatment on many literatures. Most of the results of this study were similar to the findings of the 3-phase treatment(preoperative orthodontic-orthognathic surgery-postoperative orthodontic), but total time of the treatment was shorter in patients with 2-phase treatment than in those with the conventional 3-phase treatment. With 2-phase treatment, we experienced many advantages compared to the conventional method considering that it was favarable conditions for the teeth, it had the flexibility for the treatment, and it could be the adequate treatment approach for the stomatognathic system. Although this retrospective pilot study had some limitations, due to small samples, the authors would hope that it could serve as a guide for the future researches, and the clinical applications.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.34 no.4
• /
• pp.685-693
• /
• 2007

Class I malocclusion without skeletal problem results from tooth size/arch-size discrepancies, either evidenced by crowding, or spacing problems. Treatment method can be chosen according to dentition, the amount of arch discrepancy, patient compliance, or patient demands. We report of clear aligner and spring aligner that can be applicated in cases of permanent dentition with minimal arch discrepancy in anterior segment. There are some limits of application, but these are very useful appliances in the selective case. When crowding exists, definitive analysis and diagnosis should be made before starting treatment because certain amount of space must be obtained somewhere in the dentition to resolve the crowding. Therefore, appliance should be applied when lacking space is small. Also, in cases with spacing arch circumference is reduced after alignment so no problem in intermaxilla occlusal relationship must be confirmed. In case with crowding, judicious removal of interproximal enamel is indicated.

• The korean journal of orthodontics
• /
• v.35 no.6 s.113
• /
• pp.451-458
• /
• 2005

Cephalometric superimposition is unable to evaluate tooth movement along the occlusal plane and the errors of photographing and superimposition of the occlusogram is also inevitable. The purpose of the present study was to evaluate the rotational movements of the maxillary posterior teeth following space closure after extraction of maxillary first premolars. using 3D dental images. In 19 adult females. analysis of rotational movements of the maxillary posterior teeth was performed between the initial and final 3D dental images superimposed on the maxillary hard palate. The results showed a diversity of rotational movements of posterior teeth. The causes of various rotational movements may be different rotation of molars in each case at the beginning of treatment. individual characters of the dental arch and tooth morphology. The results of the study indicate that accurate evaluation of rotational movements of posterior teeth following space closure after extraction of premolars using 3D dental images can be obtained through the subdivision of tooth movement during the initial aligning, space closure and finishing stages.

• The Journal of Korean Academy of Prosthodontics
• /
• v.51 no.1
• /
• pp.27-32
• /
• 2013

Purpose: The aims of this study were to evaluate the effect of a resin coating on the shear bond strength of indirect composite restoration bonded to dentin with a self adhesive resin cement and to compare the shear bond strength with that of a conventional resin cement. Materials and methods: The occlusal enamels of thirty six extracted noncarious human molars were removed until the dentin flat surfaces of the teeth were exposed. Then, they were divided into 3 groups. The dentin surfaces of group 1 and 3 were left without any conditioning, while the dentin surfaces of group 2 were resin-coated with Clearfil SE bond and a flowable resin composite, Metafil Flo. After all specimens were temporized for 24 hours, indirect composite resin blocks fabricated by Tescera were bonded to dentins by Unicem for group 1 and 2, and by Panavia F for group 3. After 48 hours of water storage, shear bond strengths were measured. The data was analyzed with one-way analysis of variance and multiple comparison test (Tukey method). Results: The shear bond strengths of Unicem applied to resin coated dentin surfaces were significantly higher than those of Unicem and Panavia F used to uncoated dentin surfaces (P<.0001). Conclusion: Application of a resin coating to the dentin surface significantly improved the shear bonding strength of a self adhesive resin cement in indirect restoration.

• Imaging Science in Dentistry
• /
• v.44 no.4
• /
• pp.257-262
• /
• 2014

Purpose: This study was performed to evaluate the effect of changing the orientation of a reconstructed image on the accuracy of linear measurements using cone-beam computed tomography (CBCT). Materials and Methods: Forty-two titanium pins were inserted in seven dry sheep mandibles. The length of these pins was measured using a digital caliper with readability of 0.01 mm. Mandibles were radiographed using a CBCT device. When the CBCT images were reconstructed, the orientation of slices was adjusted to parallel (i.e., $0^{\circ}$), $+10^{\circ}$, $+12^{\circ}$, $-12^{\circ}$, and $-10^{\circ}$ with respect to the occlusal plane. The length of the pins was measured by three radiologists, and the accuracy of these measurements was reported using descriptive statistics and one-way analysis of variance (ANOVA); p<0.05 was considered statistically significant. Results: The differences in radiographic measurements ranged from -0.64 to +0.06 at the orientation of $-12^{\circ}$, -0.66 to -0.11 at $-10^{\circ}$, -0.51 to +0.19 at $0^{\circ}$, -0.64 to +0.08 at $+10^{\circ}$, and -0.64 to +0.1 at $+12^{\circ}$. The mean absolute values of the errors were greater at negative orientations than at the parallel position or at positive orientations. The observers underestimated most of the variables by 0.5-0.1 mm (83.6%). In the second set of observations, the reproducibility at all orientations was greater than 0.9. Conclusion: Changing the slice orientation in the range of $-12^{\circ}$ to $+12^{\circ}$ reduced the accuracy of linear measurements obtained using CBCT. However, the error value was smaller than 0.5 mm and was, therefore, clinically acceptable.

• Restorative Dentistry and Endodontics
• /
• v.18 no.2
• /
• pp.395-411
• /
• 1993

The purpose of this study was to examine the clear concept of the designs for cavity preparations. Among the several parameters in cavity designs, profound understanding of isthmus width factor would facilitate selection of the appropriate cavity preparation for a specific clinical situation. In this study, the cavities were prepared on maxillary first premolar and filled with gold inaly. A two - dimensional model was composed of 1037 - node triangle elements. In this model, isthmus was varied in width at 1/4, 1/3 and 1/2 of intercuspal width and material properties were given for four element groups, i.e., enamel, dentin, pulp and gold. The 500N occlusal load varied in direction and it was examined using three types of load : concentrated load, divided load and distributed load. The models were also examined with empty cavities using the devided load and distributed load. These models were analyzed the displacement and strees distribution by the two - dimensional Finite Element Method. The results were as follows : 1. All experimental models which filled with gold inlay after cavity preparation were similar direction of displacement with control model under same load type. But in the models with empty cavities, as isthmus width was wider, the degree of displacement was increased at same load type. 2. Among the experimental models which were filled with gold inaly after cavity preparation, the model II showed the least stress concentration under concentrated load and divided load. But in the models with empty cavities, the model III showed the largest stress concentration and tooth fracture is expected regardless isthmus width. 3. All experimental models showed similar displacement pattern beneath restorative material under a concentrated load. In the models with empty cavities, a divided load resulted in a lingual displacement of the lingual cusp, but a distributed load resulted in a buccal displacement of the lingual cusp. In regard to the above results, the restored models were stronger than empty models in respect to the bending moment and tensile stress. The empty models are expected to fracture regardless isthmus width. The safest isthmus width was 1/3 of intercuspal distance, which showed the least stress concentration in respect to the effect of stress distribution.

• Journal of Technologic Dentistry
• /
• v.28 no.2
• /
• pp.331-346
• /
• 2006

Free-end partial dentures, which are supported by teeth surrounded by dental root membranes and elastic mucous membrane tissues, may cause stress to the abutment teeth due to external force imposed on the denture base, increase the mobility of the abutment teeth, and bring about a change in the periodontal tissue. General retainers used in partial dentures are categorized into clasp, attachment, and Konus crown. Stress imposed on the abutment teeth and mobility of the denture base have relations with the lifetime of a crown and abutment teeth, and have direct relations with the chewing ability. Thus, a need arises to make a comparative analysis of stress of the three direct retainers on the abutment teeth and interpret the mobility of the denture base. This study designed three kinds of removable partial dentures (one kind of attachment partial denture, one kind of Konus crown partial denture, and one kind of clasp partial denture), and fabricated Dentiforms of bilateral partial dentures (Kennedy Class I) with lower left 1st premolar and lower right 1st and 2nd premolars being as the abutment teeth. A strain gauge was installed in the mesial and distal surface of the lowerr left 1st premolar (No. 34) of the fabricated dentiform and in the lower part of the denture base, and installed were a clasp partial denture, an attachment partial denture, and a Konus crown partial denture. Then, the vertical static load of 5kgf and 7.5kgf at the occlusion surface of the lower left No. 6 molar was generated for a total of 20 frequencies of load each using a push-full gauge, and thus a change in the output of the strain gauge was measured. With the respective application of Konus crown, attachment and RPI clasp in the free-end partial denture, surveyed was the distribution of stress imposed on the abutment teeth and the denture base according to the location of occlusion force load so as to come up with the following results. 1. Konus crown and attachment partial dentures generated much stress, and more stress on the abutment teeth than RPI clasp dentures did. Attachment dentures tended to further intensify stress on the abutment teeth than Konus crown dentures did. 2. Attachment dentures and Konus dentures imposed less stress on the denture base than RPI clasp dentures did. There was no stress difference between Attachment and Konus crown dentures. 3. Dentures that were designed with the application of retainers using sturdy linkage methods tended to be less mobile.

• Journal of Periodontal and Implant Science
• /
• v.32 no.1
• /
• pp.41-49
• /
• 2002

The aim of this study was to compare periodontal conditions around mesially tipped molars by a tipping degree. Patients who had been consecutively treated at the Department of Periodontology, Chonbuk National University Hospital from October 1999 to August 2001 were assessed with radiographs taken at their molar regions. Of all molars investigated, 142 molars of 116 patients tipped mesially more than 10 degrees to the line perpendicular to an occlusal plane were selected for the study. The tipped molars were divided into 2 groups with a reference to a tipping degree, i.e., 66 slightly tipped(group 1 : <$30^{\circ}$) and 76 severely tipped molars (group 2 : ${\geq}30^{\circ}$). Probing depth(PD), plaque retention index(PRI) at mesial surfaces of tipped molars and tooth mobility(TM) were recorded at the clinical examination. Tipping degree(TD) and alveolar bony defect(ABD) at the mesial surface of the molars were measured in a radiograph. The results showed that no statistical differences were found between groups in all measured variables. In Pearson correlation analysis performed in the same group, a positive relationship was shown between PRI and PD in the group 1 and, in the group 2, between PRI and PD as well as PRI and ABD(p < 0.01). However, no statistically significant relationship was found between TD and all other variables in both groups. Within limitations of this study, it may be concluded that tipping degree did not seem to influence periodontal conditions, i.e., PD, ABD and TM of mesially tipped molars per se, but plaque presence/absence seemed to mainly affect the periodontal conditions of the tipped molars.