Independent prognostic factors of 861 cases of oral squamous cell carcinoma in Korean adults.

Oral squamous cell carcinoma (OSCC) accounts for 4.5% of all malignant tumors in Korean males and 3.5% in Korean females. The high recurrence rate, and in particular the high local recurrence rate, constitutes a major therapeutic problem for the Korean population, yet there is a paucity of reports addressing the independent predictors of response and survival rate of OSCC in Korea. The present study was designed to investigate the prognostic value of clinical and demographic data within a set of 861 cases of OSCC in Korea. The medical records of 861 OSCC patients who received treatment between 1984 and 1996 at 22 Korean hospitals were reviewed retrospectively with respect to several patient characteristics, including age at diagnosis, gender, location, TNM stage, and treatment. Independent patient-related and treatment-related factors that significantly influenced disease outcome after treatment were analyzed. To assess the independent factors affecting survival rate, univariate and multivariate regression analyses of the survival data were performed using the Cox proportional hazards model. A tree-structured survival model was also derived using survival tree with unbiased detection of interaction (STUDI). The multivariate Cox regression analysis showed that age, gender, composite stage, and treatment method were significant independent prognostic factors. Radiation dose, stage, size of tumor mass, and age of patient also strongly impacted survival time. OSCC is an extremely malignant carcinoma whose prognostic factors are multiple and complex. Based on the findings of this study, we believe that the prognosis of OSCC might depend directly on cancer stage as determined by the TNM system. Furthermore, the survival rate is positively affected by treatment of the neck upon presentation of the cancer, as this can prevent late neck disease due to persistent growth of occult metastases.

Early childhood caries: prevalence and risk factors in Seoul, Korea.

OBJECTIVE: The purpose of this study was to determine the prevalence of early childhood caries (ECC), including noncavitated lesions (d1), in children 6-59 months of age in relation to socioeconomic factors, feeding practices, and oral health behaviors in Seoul, Korea. METHODS: The children attended child care facilities and were selected from 32 primary sampling units. Two dentists examined 470 children. Parents of 383 of the subjects were interviewed by phone regarding caries risk factors. RESULTS: For children 6-59 months of age, the prevalence of ECC and severe ECC were 56.5 percent and 47.0 percent respectively. In bivariate analysis, the children whose nursing bottle contained sweetened solution had higher severe ECC prevalence (P=.035), and children whose parents reported a lower frequency of between-meal snacks showed lower ECC prevalence (P=.046). By logistic regression analysis, age and frequency of between-meal snacks were associated with the prevalence of ECC (P<.05). CONCLUSION: This study demonstrates that the prevalence of ECC was high among children in Seoul. Early educational intervention programs for pregnant women and mothers of young children should be developed based on the risk factors identified in this study.

Temporomandibular disorders in 19-year-old Korean men.

PURPOSE: The purpose of this study was to determine the prevalence and the nature of the relationships between 3 temporomandibular joint disease (TMD) symptoms and symptoms of associated structures. MATERIALS AND METHODS: This study was designed to rule out the effect from the uneven composition of the samples on TMD symptoms. The samples were collected from subjects who were of the same age, gender, district, and race. Nineteen-year old men (n = 27,978) were selected and investigated by means of questionnaires and clinical examinations. The prevalence of each symptom was studied and tried to determine the effects of the TMD-associated signs on the TMD signs. The indices allocated to reflect the TMD signs and symptoms and the others were dichotomized for bivariate analysis. The predictor variables were headache, neck pain, referred pain, stress, past trauma history in the TMJ, past TMJ dislocation, bruxism, and clenching. The outcome variables were mouth opening limitation, TMJ pain on rest, and TMJ pain during function. RESULTS: The incidence of masticatory muscle stiffness was 17.8%; TMJ sounds, 14.3%; headache, 7.2%; neck pain, 13.5%; bruxism, 8.4%; and clenching, 9.9%. Stress occurred in 12.8%, past trauma history in 11%, and previous joint dislocation in 2.5%. The experience of dislocation in the TMJ was found to be the most important risk factor in terms of mouth opening limitation (odds ratio, 4.08, P <.0001), joint pain during function (odds ratio, 5.50, P <.0001), and joint pain in the rest state (odds ratio, 4.63, P <.0001). Referred pain and the experience of trauma in TMJ were the secondary risk factors in terms of joint pain and referred pain and the stress in terms of mouth opening limitation. Considering referred pain can be induced by TMD, stress may be more related to mouth opening limitation (odds ratio, 2.18, P <.0001), and the experience of trauma in TMJ may be more related to pain in the rest state (odds ratio, 2.56, P <.0001) and during function (odds ratio, 2.47, P <.0001). CONCLUSIONS: The prevalence of TMD signs and symptoms as determined by this examination was in accord with the findings in women or mixed samples of other workers. Prior experience of a dislocated disc was found to be the most risky factor in TMD. Stress was related to limitations of mouth opening, and the experience of trauma in the TMJ was found to be related to pain in the joint region. Bruxism may not be a direct risk factor in TMD, and the clenching habit found to be more harmful than bruxism.

Cleft type and Angle's classification of malocclusion in Korean cleft patients.

This study was performed to investigate the contributing factors, such as cleft type, side of cleft, patient's age, and gender, associated with Angle's classification of malocclusion in Korean cleft patients. The records of 250 cleft patients (175 males, 75 females) who attended the Department of Orthodontics, Seoul National University Dental Hospital between 1988 and 1999 were examined. The percentages of subjects with cleft lip (CL), cleft lip and alveolus (CLA), cleft palate (CP), and cleft lip and palate (CLP) were 7.6, 19.2, 9.6, and 63.6, respectively. The overall distributions of unilateral and bilateral clefts were 76 and 24 per cent, respectively. The overall percentages of Class I, II, and III malocclusions were 18.5, 8.8, and 72.7. The frequency of Class III malocclusions was most prevalent in all age groups. Bivariate analysis showed that whilst gender was not significant, the type of cleft significantly influenced the development of a Class III malocclusion (P < 0.01). Using logistic regression analysis, subjects in the CP (P < 0.05) and CLP groups (P < 0.01) were 3.9 and 5.5 times more likely to have a Class III malocclusion than those in the CL group. There was, however, no statistical difference in the prevalence of a Class III malocclusion between the CL and the CLA groups (P > 0.05). When the degree of cleft involvement in the palate increased, so did the predominance of a Class III malocclusion.