• Title/Summary/Keyword: Injury analysis

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Analysis of Frequent Disease and Medical Expenses Structure of Patients Admitted in a Vaterans Hospital (일개 보훈병원 입원환자의 상병 및 진료비 구조분석)

  • Kim, Kyoung-Hwan;Lee, Sok-Goo;Kim, Jeong-Yeon
    • Journal of agricultural medicine and community health
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    • v.30 no.1
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    • pp.1-14
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    • 2005
  • Objectives: This study attempts to analyze the length of hospital stay and expenses of frequent disease admitted in a Vaterans Hospital. Methods: Data was collected from January 1, 2001 to December 31, 2003 from the Claim records of 9,640 patients in a Vaterans Hospital. Results: The results were as follows: 1. In age & sex distribution, there was male 70.9%, female 29.1%, and 35.8% of them is 70 age group. Frequency by insurance program was Health insurance 78.1%, Medical aid 14.2%, no insurance 4.1%, others 3.6%. Distribution of each department was internal medicine 28.3%, orthopedic surgery 21.3%, surgery 16.6%, neurosurgey 7.1%, pediatrics 5.9%. Also, in the veterans group, male to female patient ratio was 99.3% male to 0.7% female, them over 70 years old was 51.6%, and them which live in daejeon was 43.5%. 2. In frequency of disease, there was gastroenteritis 4.8%, pneumonia 3.8%, cartaract 3.7%, cerebral infarct 3.2%, hyperplasia of prostate 3.0%. In frequency of korean standard classification of diseases, there was injury and poisoning and certain other consequences of external causes 17.1%, diseases of digestive system 16.1%, diseases of musculoskeletal system and connective tissue 13.9%, diseases of respiratory system 9.4%, diseases of genitourinary system 8.6%. Also, in veterans group, frequency of them was diseases of musculoskeletal system and connective tissue 19.4%, diseases of digestive system 16.8%, injury and poisoning and certain other consequences of external causes 15.7%, diseases of genitourinary system 9.7%, diseases of circuatory system 8.2%. 3. Average length of hospital stay was 29.0 days for total patients, 51.8 days for the veterans group, 15.7 days for the non-veterans one. Average total expenses was 3,669,579 won, the veterans group 7,263,877 won, the non-veterans one 1,560,333 won. The ratio of insurer to insuree was 55.2 : 44.8, the ratio of amount paid by patient in the veterans group 61.7%, in the non-veterans one 33.0%. 4. In items of medical expenses, fee for hospital accommodation was 34.7%, fee for medication 13.2%(injection 7.8%, drug 5.4%), fee for service 48.6%(physical therapy 26.3%, operation 9.7%, laboratory examination 5.2%, radiological examination 3.1%, etc), others 3.4%. In them for the veterans group, fee for physical therapy was 35.3%, fee for hospital accommodation 35.2%, fee for injection 6.2%, fee for operation 5.9%, for the non-veterans one, fee for hospital accommodation 35.7%, fee for operation 16.4%, fee for injection 11.4%, fee for laboratory examination 8.3%. 5. In the comparison of the frequency by Korean standard classification of diseases and distance between the hospital and home, the region under 21.5Km was more frequent in symptoms, signs an abnormal clinical and laboratory findings 56.0%, injury and poisoning and certain other consequences of external causes 55.6%, diseases of the eye and adnexa 52.9%, the one over 21.5Km was more frequent in neoplasms 57.4%, diseases of musculoskeletal system and connective tissue 55.9%, diseases of genitourinary system 53.5%.

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Comparison of Association Rule Learning and Subgroup Discovery for Mining Traffic Accident Data (교통사고 데이터의 마이닝을 위한 연관규칙 학습기법과 서브그룹 발견기법의 비교)

  • Kim, Jeongmin;Ryu, Kwang Ryel
    • Journal of Intelligence and Information Systems
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    • v.21 no.4
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    • pp.1-16
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    • 2015
  • Traffic accident is one of the major cause of death worldwide for the last several decades. According to the statistics of world health organization, approximately 1.24 million deaths occurred on the world's roads in 2010. In order to reduce future traffic accident, multipronged approaches have been adopted including traffic regulations, injury-reducing technologies, driving training program and so on. Records on traffic accidents are generated and maintained for this purpose. To make these records meaningful and effective, it is necessary to analyze relationship between traffic accident and related factors including vehicle design, road design, weather, driver behavior etc. Insight derived from these analysis can be used for accident prevention approaches. Traffic accident data mining is an activity to find useful knowledges about such relationship that is not well-known and user may interested in it. Many studies about mining accident data have been reported over the past two decades. Most of studies mainly focused on predict risk of accident using accident related factors. Supervised learning methods like decision tree, logistic regression, k-nearest neighbor, neural network are used for these prediction. However, derived prediction model from these algorithms are too complex to understand for human itself because the main purpose of these algorithms are prediction, not explanation of the data. Some of studies use unsupervised clustering algorithm to dividing the data into several groups, but derived group itself is still not easy to understand for human, so it is necessary to do some additional analytic works. Rule based learning methods are adequate when we want to derive comprehensive form of knowledge about the target domain. It derives a set of if-then rules that represent relationship between the target feature with other features. Rules are fairly easy for human to understand its meaning therefore it can help provide insight and comprehensible results for human. Association rule learning methods and subgroup discovery methods are representing rule based learning methods for descriptive task. These two algorithms have been used in a wide range of area from transaction analysis, accident data analysis, detection of statistically significant patient risk groups, discovering key person in social communities and so on. We use both the association rule learning method and the subgroup discovery method to discover useful patterns from a traffic accident dataset consisting of many features including profile of driver, location of accident, types of accident, information of vehicle, violation of regulation and so on. The association rule learning method, which is one of the unsupervised learning methods, searches for frequent item sets from the data and translates them into rules. In contrast, the subgroup discovery method is a kind of supervised learning method that discovers rules of user specified concepts satisfying certain degree of generality and unusualness. Depending on what aspect of the data we are focusing our attention to, we may combine different multiple relevant features of interest to make a synthetic target feature, and give it to the rule learning algorithms. After a set of rules is derived, some postprocessing steps are taken to make the ruleset more compact and easier to understand by removing some uninteresting or redundant rules. We conducted a set of experiments of mining our traffic accident data in both unsupervised mode and supervised mode for comparison of these rule based learning algorithms. Experiments with the traffic accident data reveals that the association rule learning, in its pure unsupervised mode, can discover some hidden relationship among the features. Under supervised learning setting with combinatorial target feature, however, the subgroup discovery method finds good rules much more easily than the association rule learning method that requires a lot of efforts to tune the parameters.

A Study of Content Analysis on ICU(Intensive Care Unit) Nurses' Knowledge of Basic Nursing Sciences (중환자실 간호사의 기초간호과학 지식의 필요성 분석)

  • Byeon, Young-Soon;Choe, Myoung-Ae;Kim, Hee-Seung;Park, Mi-Jung;Seo, Wha-Sook;Lee, Kyung-Sook;Choi, S-Mi;Hong, Hae-Sook
    • Journal of Korean Biological Nursing Science
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    • v.4 no.1
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    • pp.41-49
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    • 2002
  • The purpose of this study was to identify the knowledge contents of basic nursing sciences needed by nurses in the practices of the intensive care unit(ICU). To attain the goal of this study, the nurses working at 10 hospitals in the areas of Seoul and Kangwon Province were randomly selected. They were primarily interviewed, and the open question was secondarily put to them through the questionnaire. In the process of the 1st interview, the interviewees were asked of the question, "What is the knowledge of basic sciences such as anatomy, pathology, physiology. microbiology, pharmacology and the like thought to be lacking when you communicate with doctors in the ICU and when you carry out your nursing practices in it?" The contents of the interview were tape-recorded. The period of data collection ranged from May 1, 2001 to Sept 30. The interviews were conducted with total of 20 nurses. The open-end questionnaire was secondarily mailed to nurses. 113 questionnaires were returned. 100 questionnaires except 13 ones thought to be poorly completed in content were used for data analysis. Three coders classified data obtained from the interview and the questionnaire research into 5 detailed items relating to such as anatomical physiology, pathology, pharmacology. microbiology and basics of nursing. The three coders had experiences in nursing education of 18 years, 8 years and 6 years, respectively, and of them one coder was professor in basic nursing sciences. Data were statistically treated using frequency analysis and percentage by the SAS program. As a result, the following findings were obtained : It was found that the contents that ICU nurses responded were most needed in the field of Human structure and function were water and electrolytic balance(38%), blood and circulatory system(20%), changer in the patient's skin(12%), the arrangement of the human body(10%) and the endocrine system(10%), nervous system(6%), and assessment of the state of the patient's consciousness(4%). It was found that the contents that ICU nurses responded were most needed in the field of pathology were found to be the process of the progress of the disease(32%), symptoms of the disease(27%), prognosis of the disease(22%), followed by the injury-healing process, clinical pathological examination, and examination by radiation. It was found that the contents that nurses responded were most needed in the field of pharmacology were the effect of drug(25%), the side effect of drug(22%), the relationship between diseases and drug(20%), the relationship between disease-causing bacteria and drug(20%) and chemotherapy(2%). It was found that the contents that ICU nurses responded were most needed in the field of microbiology were the relationship between diseases and disease-causing bacteria(45%), Kinds and characteristics of disease-causing bacteria(18%), infection control(16%), application of the aseptic technique(12%), isolation(9%) and the like. It was found that the basic knowledge that ICU nurses responded were needed were the identification of the patient's current state(36%), understanding of the therapeutic process(22%), the operating principle of medical equipment and instrument(20%), medical terminology(9%), equipment and instrument management(7%), calculation of the dose of injection(2%) and the like.

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Clinical Analysis of the Pediatric Patients Seen in the Emergency Medical Center (응급의료센터 소아 환자들의 경향 분석)

  • Lee, Hee Jung;Park, So Yoon;Lee, Young Hwan;Do, Byung Soo;Lee, Sam Bum
    • Clinical and Experimental Pediatrics
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    • v.48 no.10
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    • pp.1061-1067
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    • 2005
  • Purpose : We studied a clinical analysis of pediatric patients who visited the emergency medical center of Yeungnam University Hospital to compare the characteristics of pediatric emergency patients after year 2000 with the previous studies. Methods : We reviewed 7,034 children under the age of 15 years who visited the emergency medical center of Yeungnam University Hospital during the 2 year period from January 2001 to December 2002, and then we performed a clinical and statistical analysis. We analyzed the pediatric patients according to gender, age, season, day of the week, time of the visit, the disease classification and the final disposition of the patients. Results : Among the patients who visited the emergency room, 15.6% of the total emergency patients were under the age of 15. The male to female ratio was 1.6 : 1. Among the 7,034 pediatric patients, the most common age group was between 1 year and under 3 years of age(26.9%). The peak seasonal incidence was early summer and spring, especially during June(11.2%) and May(10.6 %). The peak incidence day of the week was Sunday(24.8%) and the peak time when the emergency pediatric patients visited the emergency room was between 20 and 24 o'clock(28.8%). The distribution of diseases, according to ICD-10 system, were injury and poisoning(30.4%), diseases of the respiratory system(22.8%), and diseases of the digestive system(14.6%). 30% of total pediatric patients were admitted to the hospital. Conclusion : After year 2000, as compared with the previous studies, the proportions of emergency pediatric patients has decreased. The distribution of diseases was not much different from the previous studies and the proportions of non-urgent diseases, such as acute nasopharyngitis or acute gastroenteritis, were still high. These result have come about due to the declining birth rate and changes of the medical system in Korea.

The Factors Related to Musculoskeletal Symptoms of Family Care-Givers who Have a Patient with Brain Damage (뇌손상 가족 간병인의 근골격계 자각증상과 관련요인)

  • Jeon, Eun-Mi;Lee, Seong-A;Gu, Jung-Whan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.1
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    • pp.336-344
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    • 2017
  • This study was conducted to identify factors related to the musculoskeletal symptoms of 340 family caregivers who have a patient with brain damage based on self-administered questionnaires. The questionnaires included general characteristics, characteristics of care activities and caregivers' musculoskeletal symptoms. Data were collected from many long-term care hospitals and rehabilitation centers during March 17 to March 21, 2014. The results indicated that complaint rates of work-related musculoskeletal systems of the body sites differed. Factor analysis revealed that neck complaints were related to education (under mid), while shoulder complaints were related to sex (female), age (50-59), education (mid) and duration of care (< 2 years). Arm/elbow complaints were related to age (40-49), education (high) and duration of care (12-24). Complaints regarding the hand/wrist/finger were related to age (50-59) and duration of care (12-24), while those associated with the legs/feet were related to age (50-59) and duration of care (< 6[ED highlight - years? Please specify.]). Back problems were related to education (under mid, mid stage, high) and gait. The complaint rate regarding musculoskeletal symptoms during daily life was not statistically significant. Logistic regression analysis of significant factors related to subjective musculoskeletal symptoms identified ambulation and gait as having the greatest influence and complaint factor among family caregivers. The complaint rate of family caregivers differed among body parts. Being a caregiver for less than one year was found to have a significant impact on pain. Overall, long term family caregivers could be faced with risk factors for musculoskeletal problems, but there are many different factors that affect musculoskeletal symptoms with regards to their activities. Accordingly, comprehensive and systematic prevention plans for family caregivers who have patients with brain damage should be developed.

Task Analysis of Paramedics of Korea Based on DACUM Method (DACUM 기법에 의한 1급 응급구조사의 직무분석)

  • Bae, Ki-Sook;Koh, Bong-Yeun;Lee, Jung-Eun;Lee, In-Mo;Choi, Keun-Myoung;Kim, Soo-Tae
    • The Korean Journal of Emergency Medical Services
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    • v.15 no.1
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    • pp.5-23
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    • 2011
  • Objective : This study grasps specific task on paramedics who plays a great role in the emergency scene, thereby eliciting definition of job called paramedics and analyzing occupation by DACUM method. Thus, the aim is to suggest working-level guidelines on the task of paramedics. Methods : It targeted paramedics who are working at hospitals, fire stations, and industries in Seoul and Gyeonggi area from Oct. 11, 2010 to Nov. 30. A total of 608 copies of questionnaire were analyzed by DACUM method. A research tool on occupational analysis consisted of 8 pieces for duty, 43 pieces for task, and 149 pieces for task elements. In order to survey performance frequency, importance, and difficulty by element, each task was developed by this research team, and each task was analyzed and finally elicited through workshop of DACUM method. Results : The occupational definition of paramedics, which was defined through this DACUM, was elicited as 'professional job of performing emergency medical care on the scene, during transferring, or within medical institution in order to maintain life and prevent wound deterioration, targeting a person who is put in emergency situation.' Task element, whose performance frequency was indicated to be the highest, was in order of checking mental status($2.76{\pm}0.497$), checking vital signs($2.70{\pm}0.578$), and airway/c-spine immobilization($2.69{\pm}.546$). Especially, defibrillation stood at $2.23{\pm}.655$ points. Task element, whose performance frequency was low, was in order of caring sexual abuse victims($1.32{\pm}0.563$), performing cricothyrotomy($1.36{\pm}0.618$), and caring cardiac arrest victims($1.40{\pm}0.636$). Importance of task was in order of airway/c-spine immobilization ($2.88{\pm}0.338$), maintenance of respiration($2.88{\pm}0.351$), caring cardiac arrest victims($2.87{\pm}0.349$), and performing CPR($2.87{\pm}0.361$). Task element, whose importance is low, was indicated to be in order of enema($2.29{\pm}0.736$), urinary catheterization($2.35{\pm}0.664$), and nasogastric intubation($2.35{\pm}0.667$). Task element, whose difficulty was shown to be the highest, was indicated to be in order of caring cardiac arrest victims during pregnancy ($2.60{\pm}0.559$), caring cardiovascular injury($2.59{\pm}0.546$), and labor management($2.53{\pm}0.533$). Conclusion : Based on the results of this study, the job performance work table(Dacom chart) of paramedics is suggested to be used, thereby being applied to development in education and curriculum of paramedics. It is necessary to evaluate usefulness of the job performance work table by estimating effect of education for paramedics based on the job performance work table of paramedics.

A study of the cause of metal failure in treatment of femur shaft fracture - Fractographical and clinical analysis of metal failure- (대퇴골 간부 골절시 사용한 금속물의 금속부전(Metal failure)의 기전에 대한 연구)

  • Jeon, Chun-Bae;Seo, Jae-Sung;Ahn, Jong-Chul;Ahn, Myun-Whan;Ihn, Joo-Chyl
    • Journal of Yeungnam Medical Science
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    • v.7 no.1
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    • pp.81-93
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    • 1990
  • The author fractographically analyized the cause of metal failure(the first time this procedure has been used for this metal failure)and also analyized it clinically. In this study, I selected eight cases which have been analyized fractographically. In all these cases, the analysis was done after treatment of metal failure of implants internally fixed to femur shaft fractures at the Department of Orthopedic Surgery, Yeung-Nam University Hospital during the six year period from May 1983 to September 1989. 1. Metal failure occured in five dynamic-compression plates, one Jewett nail, one screw in Rowe plate, and one interlocking nail. 2. The clinical cause of metal failure was deficiency of medial butress in five cases, incorrect position of implant in one case, and incorrect selection of implant in two cases. 3. The time interval between internal fixation and metal failure was four months in one case, between five months to twelve months in six cases, three years in one case. 4. The fractographically analytical cause of metal failure was ; first, impact failure, one case, second, fatigue failure, six cases, machining mark(stress liser), four cases type : low consistent cyclic fatigue failure irregular cyclic fatigue failure third, stress corrosion crack, one case. 5. 316L Stainless Steel has good resistance to corrosion. However, when its peculiar surface film is destroyed by fretting, it shows pitting corrosion. This is, perhaps, the main cause of metal failure. 6. It is possible that mechanical injury occured in implants during the manufacturing of implants or that making a screw hole is the main cause of metal failure.

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A basic study on explosion pressure of hydrogen tank for hydrogen fueled vehicles in road tunnels (도로터널에서 수소 연료차 수소탱크 폭발시 폭발압력에 대한 기초적 연구)

  • Ryu, Ji-Oh;Ahn, Sang-Ho;Lee, Hu-Yeong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.6
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    • pp.517-534
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    • 2021
  • Hydrogen fuel is emerging as an new energy source to replace fossil fuels in that it can solve environmental pollution problems and reduce energy imbalance and cost. Since hydrogen is eco-friendly but highly explosive, there is a high concern about fire and explosion accidents of hydrogen fueled vehicles. In particular, in semi-enclosed spaces such as tunnels, the risk is predicted to increase. Therefore, this study was conducted on the applicability of the equivalent TNT model and the numerical analysis method to evaluate the hydrogen explosion pressure in the tunnel. In comparison and review of the explosion pressure of 6 equivalent TNT models and Weyandt's experimental results, the Henrych equation was found to be the closest with a deviation of 13.6%. As a result of examining the effect of hydrogen tank capacity (52, 72, 156 L) and tunnel cross-section (40.5, 54, 72, 95 m2) on the explosion pressure using numerical analysis, the explosion pressure wave in the tunnel initially it propagates in a hemispherical shape as in open space. Furthermore, when it passes the certain distance it is transformed a plane wave and propagates at a very gradual decay rate. The Henrych equation agrees well with the numerical analysis results in the section where the explosion pressure is rapidly decreasing, but it is significantly underestimated after the explosion pressure wave is transformed into a plane wave. In case of same hydrogen tank capacity, an explosion pressure decreases as the tunnel cross-sectional area increases, and in case of the same cross-sectional area, the explosion pressure increases by about 2.5 times if the hydrogen tank capacity increases from 52 L to 156 L. As a result of the evaluation of the limiting distance affecting the human body, when a 52 L hydrogen tank explodes, the limiting distance to death was estimated to be about 3 m, and the limiting distance to serious injury was estimated to be 28.5~35.8 m.

Clinical Results after Repair of Rotator Cuff Tear in Patients with Accompanying AC Joint Pathology: Clinical Comparison of Non-operative Treatment (회전근개 파열과 동반된 견봉 쇄골 관절 병변이 회전근개 봉합술 후 결과에 미치는 영향: 비수술적 치료를 통한 임상적 비교)

  • Yoo, Moon-Jib;Seo, Joong-Bae;Lee, Dae-Hee;Kim, Sung-Jin
    • Clinics in Shoulder and Elbow
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    • v.15 no.2
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    • pp.86-90
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    • 2012
  • Purpose: We studied the need for distal clavicle resection by comparing rotator cuff tear patients who underwent non-surgical treatment with and without acromioclavicular joint pathology. Materials and Methods: 45 cases that had been under follow up care for at least 9 months after receiving rotator cuff repair in our hospital between Jan. 2005 and Jun. 2011 had been studied. Acromioclavicular joint pathology group and control group were classified by physical examination and MRI findings. The temporal changes in shoulder joint abduction, internal and external rotation strength, ASES and KSS score of the two groups were measured and analyzed. Results: The acromioclavicular joint pathology complicated rotator cuff injury group's strength measurements for abduction, internal rotation, external rotation were each 8.05 (${\pm}4.54$), 11.33 (${\pm}6.05$), 10.24 (${\pm}5.27$) preoperatively and improved to 13.26 (${\pm}5.50$), 17.51 (${\pm}6.80$), 15.60 (${\pm}5.37$) post operatively while the KSS score and ASES score were each 49.07 (${\pm}15.28$) and 48.65 (${\pm}13.27$) preoperatively, improving to 84.48 (${\pm}10.96$) and 84.65. (${\pm}9.86$). The measurements for the group without complicating acromioclavicular pathology are as follows. The strength for abduction, internal rotation, external rotation was each 6.42 (${\pm}3.11$), 7.59 (${\pm}4.81$) and 7.93 (${\pm}4.49$) preoperatively, improving to 15.85 (${\pm}7.35$), 19.18 (${\pm}9.14$), 16.95 (${\pm}5.70$) post operatively, while the KSS score and ASES score each went from 42.12 (${\pm}6.43$) and 41.37 (${\pm}7.42$) to 83.44 (${\pm}6.30$) and 83.17 (${\pm}7.01$) respectively. The measurements for the two groups, however, did not show a statistically significant difference (p>0.05). Conclusion: Analysis of the rotator cuff injury groups with and without AC joint pathology showed that both groups had improved strength, ASES and KSS scores with no statistical difference difference among the groups. As such, it thought that conservative treatment is an acceptable alternative to distal clavicle resection.

A STUDY ON THE TEMPERATURE CHANGES OF BONE TISSUES DURING IMPLANT SITE PREPARATION (임플랜트 식립부위 형성시 골조직의 온도변화에 관한 연구)

  • Kim Pyung-Il;Kim Yung-Soo;Jang Kyung-Soo;Kim Chang-Whe
    • The Journal of Korean Academy of Prosthodontics
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    • v.40 no.1
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    • pp.1-17
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    • 2002
  • The purpose of this study is to examine the possibility of thermal injury to bone tissues during an implant site preparation under the same condition as a typical clinical practice of $Br{\aa}nemark$ implant system. All the burs for $Br{\aa}nemark$ implant system were studied except the round bur The experiments involved 880 drilling cases : 50 cases for each of the 5 steps of NP, 5 steps of RP, and 7 steps of WP, all including srew tap, and 30 cases of 2mm twist drill. For precision drilling, a precision handpiece restraining system was developed (Eungyong Machinery Co., Korea). The system kept the drill parallel to the drilling path and allowed horizontal adjustment of the drill with as little as $1{\mu}m$ increment. The thermocouple insertion hole. that is 0.9mm in diameter and 8mm in depth, was prepared 0.2mm away from the tapping bur the last drilling step. The temperatures due to countersink, pilot drill, and other drills were measured at the surface of the bone, at the depths of 4mm and 8mm respectively. Countersink drilling temperature was measured by attaching the tip of a thermocouple at the rim of the countersink. To assure temperature measurement at the desired depths, 'bent-thermocouples' with their tips of 4 and 8mm bent at $120^{\circ}$ were used. The profiles of temperature variation were recorded continuously at one second interval using a thermometer with memory function (Fluke Co. U.S.A.) and 0.7mm thermocouples (Omega Co., U.S.A.). To simulate typical clinical conditions, 35mm square samples of bovine scapular bone were utilized. The samples were approximately 20mm thick with the cortical thickness on the drilling side ranging from 1 to 2mm. A sample was placed in a container of saline solution so that its lower half is submerged into the solution and the upper half exposed to the room air, which averaged $24.9^{\circ}C$. The temperature of the saline solution was maintained at $36.5^{\circ}C$ using an electric heater (J. O Tech Co., Korea). This experimental condition was similar to that of a patient s opened mouth. The study revealed that a 2mm twist drill required greatest attention. As a guide drill, a twist drill is required to bore through a 'virgin bone,' rather than merely enlarging an already drilled hole as is the case with other drills. This typically generates greater amount of heat. Furthermore, one tends to apply a greater pressure to overcome drilling difficulty, thus producing even greater amount heat. 150 experiments were conducted for 2mm twist drill. For 140 cases, drill pressure of 750g was sufficient, and 10 cases required additional 500 or 100g of drilling pressure. In case of the former. 3 of the 140 cases produced the temperature greater than $47^{\circ}C$, the threshold temperature of degeneration of bone tissue (1983. Eriksson et al.) which is also the reference temperature in this study. In each of the 10 cases requiring extra pressure, the temperature exceeded the reference temperature. More significantly, a surge of heat was observed in each of these cases This observations led to addtional 20 drilling experiments on dense bones. For 10 of these cases, the pressure of 1,250g was applied. For the other 10, 1.750g were applied. In each of these cases, it was also observed that the temperature rose abruptly far above the thresh old temperature of $47^{\circ}C$, sometimes even to 70 or $80^{\circ}C$. It was also observed that the increased drilling pressure influenced the shortening of drilling time more than the rise of drilling temperature. This suggests the desirability of clinically reconsidering application of extra pressures to prevent possible injury to bone tissues. An analysis of these two extra pressure groups of 1,250g and 1,750g revealed that the t-statistics for reduced amount of drilling time due to extra pressure and increased peak temperature due to the same were 10.80 and 2.08 respectively suggesting that drilling time was more influenced than temperature. All the subsequent drillings after the drilling with a 2mm twist drill did not produce excessive heat, i.e. the heat generation is at the same or below the body temperature level. Some of screw tap, pilot, and countersink showed negative correlation coefficients between the generated heat and the drilling time. indicating the more the drilling time, the lower the temperature. The study also revealed that the drilling time was increased as a function of frequency of the use of the drill. Under the drilling pressure of 750g, it was revealed that the drilling time for an old twist drill that has already drilled 40 times was 4.5 times longer than a new drill The measurement was taken for the first 10 drillings of a new drill and 10 drillings of an old drill that has already been used for 40 drillings. 'Test Statistics' of small samples t-test was 3.49, confirming that the used twist drills require longer drilling time than new ones. On the other hand, it was revealed that there was no significant difference in drilling temperature between the new drill and the old twist drill. Finally, the following conclusions were reached from this study : 1 Used drilling bur causes almost no change in drilling temperature but increase in drilling time through 50 drillings under the manufacturer-recommended cooling conditions and the drilling pressure of 750g. 2. The heat that is generated through drilling mattered only in the case of 2mm twist drills, the first drill to be used in bone drilling process for all the other drills there is no significant problem. 3. If the drilling pressure is increased when a 2mm twist drill reaches a dense bone, the temperature rises abruptly even under the manufacturer-recommended cooling conditions. 4. Drilling heat was the highest at the final moment of the drilling process.