• Journal of dental hygiene science
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• v.3 no.1
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• pp.33-38
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• 2003

One aspect of undesirable outcomes in orthodontic treatment includes excessive resorption of dental roots with mechanotherapy. The aim of this study is to demonstrate whether diseases affecting the immune system adversely are prevalent in orthodontic patients who manifest excessive resorption of dental roots with orthodontic tooth movement. The records of 51 orthodontic patients (25 males and 26 females, $16.1{\pm}3.3$ yr old) and 51 pair-matched controls ($1.5.4{\pm}4.1$ yr old) were analyzed retrospectively. The pretreatment questionnaires and the treatment records disclosed that the incidence of asthma, allergy, and signs indicative of psychological stress, was significantly higher in the root resorption cohort. The immune system is either altered or adversely affected in all these conditions. Since the progenitors of osteoclasts and odontoclasts are derived from mononucleated cells of monocyte and macrophage lineage, which are prominent cellular members of the immune system, the study leaded to the conclusion that excessive root resorption may occur in orthodontic patients who are psychologically stressed, or who have asthma and allergy, or any other conditions that may adversely affect and modify the immune system, and a careful examination and interpretation of a patient's medical history may be beneficial to both patient and practioner.

• The korean journal of orthodontics
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• v.38 no.4
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• pp.283-298
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• 2008

Objective: The purpose of this study was to investigate changes in the mandibular dental arch from presurgical orthodontic treatment and orthognathic surgery, and to evaluate the relationships between the pretreatment records and changes of mandibular dental arch in skeletal Class III malocclusion individuals. Methods: Lateral cephalometric radiographs and mandibular study models of 31 adults with skeletal class III malocclusion were taken and measured. All measurements were evaluated statistically by ANOVA, Scheffe's Post Hoc, and paired t-test, and correlation coefficients were evaluated. Results: No significant difference in Mn-LMMC, Mn-LIE, Mn-MnOcc was detected between pretreatment and presurgical groups. Statistically significant but low correlations were demonstrated between the initial arch length discrepancy (ALD) and change in ICW, IPW1 (r = 0.492, 0.615) and change in arch length (r = 0.641). No association was seen between the initial depth of curve of Spee and change in mandibular incisor angle and arch width or arch length. Regression analysis showed that the amount of change for arch length and IPW1 could be explained by 64.0% and 75.8% of the pretreatment variables respectively. Conclusions: This study suggests that orthognathic surgery results can be predictable by measuring the pretreatment records.

• Journal of Korean society of Dental Hygiene
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• v.4 no.2
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• pp.265-276
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• 2004

The purpose of this study,was to find out health status, characteristics related to working conditions, occurrence of low back pain and its related factors among dental hygienists working in dental clinics, and, thus, to provide basic information necessary to set up some plans for preventing the occurrence of low back pains and improving working conditions for dental hygienists. The data were collected from 310 dental hygienists working at dental clinics in Pusan and Kyungnam area, including Masan, Changwon, Jinhae and Jinju, with a self-administered questionnaire and were analyzed finally for 295 records with SPSS for Windows(7.52K) program. The results were as follows : Working condition was considered to be fair by 562% of dental hygienists were thought to threaten their health in the dental clinics. About seventy percent of dental hygienists worked over ten hours a day and 72.8% were standing while working over 7 hours, 65% considered working hours too long. Health status was thought be more than average for 82.3% while more than half perceived certain degree of stress frequently. The rate of complaining low back pains among dental hygienists was 87.8% with pains more than medium level for 39.3%. The variables significantly related to the degree of low back pains were height, uncomfortable postures, type of working postures and the height of working table, while some variables including height, hours of working on the feet, the presence of hazardous work environment, uncomfortable postures, the presence of hazardous works, the amount of working hours, type of working postures and work-associated stresses, were significantly related to the number of symptoms for low back pains. Multiple regression analysis showed that occurrence of low back pains was significantly influenced by 5 factors such as subjective status of health, work-related stresses, the degree of perception to work environment, the degree of perception to the amount of working hours and age. In conclusion, it might be necessary to manage working conditions effectively by reducing working hours, making good postures while working and removing stressful conditions in order to reduce risk factors for the occurrence of low back pains among dental hygienists. Therefore good working postures, assignment of appropriate rest time and some programs for early detection, care and education of low back pains should be provided for the dental hygienists.

• Journal of Periodontal and Implant Science
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• v.48 no.2
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• pp.103-113
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• 2018

Purpose: The purpose of this retrospective study with 4-12 years of follow-up was to compare the marginal bone loss (MBL) between external-connection (EC) and internal-connection (IC) dental implants in posterior areas without periodontal or peri-implant disease on the adjacent teeth or implants. Additional factors influencing MBL were also evaluated. Methods: This retrospective study was performed using dental records and radiographic data obtained from patients who had undergone dental implant treatment in the posterior area from March 2006 to March 2007. All the implants that were included had follow-up periods of more than 4 years after loading and satisfied the implant success criteria, without any peri-implant or periodontal disease on the adjacent implants or teeth. They were divided into 2 groups: EC and IC. Subgroup comparisons were conducted according to splinting and the use of cement in the restorations. A statistical analysis was performed using the Mann-Whitney U test for comparisons between 2 groups and the Kruskal-Wallis test for comparisons among more than 2 groups. Results: A total of 355 implants in 170 patients (206 EC and 149 IC) fulfilled the inclusion criteria and were analyzed in this study. The mean MBL was 0.47 mm and 0.15 mm in the EC and IC implants, respectively, which was a statistically significant difference (P<0.001). Comparisons according to splinting (MBL of single implants: 0.34 mm, MBL of splinted implants: 0.31 mm, P=0.676) and cement use (MBL of cemented implants: 0.27 mm, MBL of non-cemented implants: 0.35 mm, P=0.178) showed no statistically significant differences in MBL, regardless of the implant connection type. Conclusions: IC implants showed a more favorable bone response regarding MBL in posterior areas without peri-implantitis or periodontal disease.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.3
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• pp.258-265
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• 2008

Purpose. This multicenter retrospective study was performed to evaluate the survival and success rates of immediate placement of USII and SSII Osstem implant (Osstem implant Co, Korea) on the maxillary and mandibular anterior and premolar areas. Materials and methods. Dental records were obtained in 37 patients who were treated with immediate implantation on the maxillary and mandibular anterior and premolar areas in 6 different clinics. The 98 implants were evaluated both clinically and radiographically using predefined success criteria. Results. There was no failed implant in all patients. The mean follow up period was 24.7 months (ranged from 12 to 58 months), and 25.1 months (ranged from 16 to 35 months) in USII and SSII implants, respectively. The crestal bone loss was 3 mm in 3 USII implants during 41 months, and in 1 SSII implant during 22 months. The overall success rate was 94.2% and 97.7% in USII and SSII implants, respectively. The age, gender, diameter, or length of implants, and type of surgery were not influenced to the success rate of immediate implantation. Conclusion. These results suggest that USII and SSII Osstem implant can be used successfully in immediate implantation on the maxillary and mandibular anterior and premolar areas.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.8 no.1
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• pp.1-9
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• 2012

Mobile oral exam at the facilities for the disabled in Seoul is to improve the oral health of the disabled who can hardly approach dental clinic. We analyzed 1609 oral exam records at 24 facilities (11 special-education schools, 10 living facilities, 2 mental hospitals, 1 health care facility for the elderly) in 2011. The purpose of this study is to figure out the oral health state of the disabled in facilities in Seoul and to compare with the non-disabled in National Survey 2010 and 2008. 1. Special-education school : DMFT index of age 15 is 5.4 which is higher than 3.6 (DMFT index of age 15) of National Survey in 2010. 2. Living facility : DMFT index of ages 35~44 is 8.4 which is higher than 5.2 (DMFT index of ages 35 ~44) of National Survey in 2008. DT rate is higher (31.3% vs 19.2%) and MT rate is lower (7.6% vs 15.5%). 3. Mental hospital : DMFT index of ages 35~44 is 11.3 which is higher than 5.2 (DMFT indext of age 35~44) of National Survey in 2008. DT rate is significantly higher (50.7% vs 19.2%) and FT rate is lower (35.1% vs 65.3%). 4. Health care facility for the elderly : DMFT index of ages 65~74 is 7.1 which is slightly lower than 8.7 (DMFT index of ages 65~74) of National Survey in 2008. The number of existing natural teeth is similar (16 vs 18).

• The Journal of Advanced Prosthodontics
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• v.9 no.3
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• pp.195-199
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• 2017

PURPOSE. The objective of this study was to determine the cumulative survival rate (CSR) and associated risk factors of Implantium implants by retrospective clinical study. MATERIALS AND METHODS. Patients who received Implantium implants (Dentium Co., Seoul, Korea) at Korea University Guro Hospital from 2004 to 2011 were included. The period between the first surgery and the last hospital visit until December 2015 was set as the observation period for this study. Clinical and radiographic data were collected from patient records, including all complications observed during the follow-up period. Kaplan-Meier analysis was performed to examine CSR. Multiple Cox proportional hazard model was employed to assess the associations between potential risk factors and CSR. RESULTS. A total of 370 implants were placed in 121 patients (mean age, 56.1 years; range, 19 to 75 years). Of the 370 implants, 13 failed, including 7 implants that were lost before loading. The 10-year cumulative survival rate of implants was 94.8%. The multiple Cox proportional hazard model revealed that significant risk factor of implant failure were smoking and maxillary implant (P<.05). CONCLUSION. The 10-year CSR of Implantium implants was 94.8%. Risk factors of implant failure were smoking and maxillary implant.

• The korean journal of orthodontics
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• v.48 no.4
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• pp.268-280
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• 2018

Resistance to sliding (RS) between the bracket, wire, and ligature has been largely debated in orthodontics. Despite the extensive number of published studies, the lack of discussion of the methods used has led to little understanding of this phenomenon. The aim of this study was to discuss variables affecting RS in orthodontics and to suggest an operative protocol. The search included $PubMed^{(c)}$, $Medline^{(c)}$, and the Cochrane $Library^{(c)}$. References of full-text articles were manually analyzed. English-language articles published between January 2007 and January 2017 that performed an in vitro analysis of RS between the bracket, wire, and ligature were included. Study methods were analyzed based on the study design, description of materials, and experimental setup, and a protocol to standardize the testing methods was proposed. From 404 articles identified from the database search and 242 records selected from published references, 101 were eligible for the qualitative analysis, and six for the quantitative synthesis. One or more experimental parameters were incompatible and a meta-analysis was not performed. Major factors regarding the study design, materials, and experimental setup were not clearly described by most studies. The normal force, that is the force perpendicular to the sliding of the wire and one of the most relevant variable in RS, was not considered by most studies. Different variables were introduced, often acting as confounding factors. A protocol was suggested to standardize testing procedures and enhance the understanding of in vitro findings.

• Imaging Science in Dentistry
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• v.49 no.4
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• pp.287-294
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• 2019

Purpose: This study was performed to analyze the clinical and imaging features of contemporary osteomyelitis(OM) and to investigate differences in these features on panoramic radiography according to patients' history of use of medication affecting bone metabolism. Materials and Methods: The records of 364 patients(241 female and 123 male, average age 66.8±14.9 years) with OM were retrospectively reviewed. Panoramic imaging features were analyzed and compared between patients with medication-related OM(m-OM) and those with conventional, medication-unrelated OM(c-OM). Results: The age of onset of OM tended to be high, with the largest number of patients experiencing onset in their 70s. The 2 most frequent presumed causes were antiresorptive medication use (44.2%) and odontogenic origin (34.6%). On panoramic radiographs, a mix of osteolysis and sclerosis was the most common lesion pattern observed (68.6%). Sequestrum, extraction socket, and periosteal new bone formation were found in 143(42.1%), 79 (23.2%), and 24 (7.1%) cases, respectively. The m-OM group exhibited sequestrum and extraction socket more frequently and displayed significantly higher mandibular cortical index values than the c-OM group. Conclusion: We observed some differences in imaging features as shown on panoramic radiography according to the history of antiresorptive medication use. This study may help elucidate the predictive imaging features of medication-related osteonecrosis of the jaw.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.141-152
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• 1996

Oral Lichen Planus(OLP) is a idiopathic chronic inflammatory disease with more difficult to clear and higher recurrent rate than cutaneous lesions. But, there has been no estabilished theories about the proper treatment for OLP. The purpose of this study is to examine the clinical feature, relationship with systemic disease and dental treatment of OLP patients of Korea and to gain helpful information about clinical characteristics and treatment of OLP. The subjects chosen for the study were 54 patients who had visited Department of Oral Diagnosis & Oral Medicine at Yonsei University Dental Hospital Dental Hospital and diagnosed as OLP. Previous clinical records has been reviewed and questionnaires, oral examination, laboratory examination were done and recorded. The following results were obtained : 1. Of the 54 patients, 21 were men and 33 were women with an average age of 47.8 years. 2. The most common intraoral site was bilateral buccal mucosa, followed by unilateral buccal mucosa, gingiva, vesibule, lip mucosa, glossal mucosa, palatal mucosa and mouth floor. 3. The mixed, erosive and reticular form of OLP was most frequent(83.3%) clinical form. 4. OLP patients with liver disease were 5, and drug medication patients were 7. But, we could not find its evidence of association with OLP. 5. Associated events on onset of symptom were stress, denture wearing, dental treatemtn, and common cold. 6. Associated symptoms were dry mouth, tingling, sore throat, and altered taste perception. 30.8% of patients had no specific associated symptoms. 7. Aggravating factors of symptom were peppery food, hot food, fatigue, toothpaste, salty food, sour food, tension, and conversation. Reducing factors were cold food, sleeping. 69.2% of patients had no specific reducing factors. 8. There were no significant differences between normal papulation and OLP patients in CBC, SGOT< SGPT, Serum iron, Total iron binding capacity. 66.7% of subjects were positive response to fungus study for Candida Albicans. The incidence of stress and dental treatment on onset of symptom appeared high in OLP patients. Especially, high incidence of positive response to fungus study for Candida albicans, prescription of anti-fungal agents and dental treatment considerations may be helpful to treatment of OLP.