• Maxillofacial Plastic and Reconstructive Surgery
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• 제23권2호
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• pp.155-162
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• 2001

This is a clinical study on patients who had visitied the Emergency Room of Pusan National University Hospital and then been treated in the Department of Oral and Maxillofacial Surgery during recent 5 years, from 1992 to 1996. The results were as follow ; 1. The total number of patients was 2,680 and the ratio of male to female was 1.96:1, The highest monthly incidence was shown in September(12.1%) and October(10.5%) and the age distribution peaks was the third decade(24.3%), followed by the first(23.1%) and the fourth decade(17.2%). 2. Soft tissue injury group(29.1%) was the most prevalent, followed by tooth injury group(16.1%), facial bone injury group (16.0%), toothache group(11.2%), socket bleeding group(11.1%), infection group(9.8%) and TMJ dislocation group(5.9%). 3. The percentage of in-patients and out-patient were 21.6% and 78.4%, respectively. The frequent causes of admission were facial bone fracture(73.8%), infection(20.8%) and soft tissue injury(4.8%) in order. However, soft tissue injury was the most frequent cause in out-patient, followed by tooth injury(20.5%), toothache(14.3%), socket bleeding(14.2%) and TMJ dislocation(7.6%). 4. In the facial bone injury group, the mandibular fractures(70.6%) showed the highest incidence, followed by zygomatic bone and arch fractures(7.5%), maxillary bone fractures(4.0%) and nasal bone fractures(4.0%). 5. In the mandibular bone fracture, the most common location was symphysis(36.7%), followed by the mandibular angles(33.1%) and the condyles(21.8%). 6. The common causes of facial bone fractures were violence, fall and traffic accident in order. 7. The common causes of soft tissue injury were fall down, fight and traffic accident in order and the highest incidence was observed in infants before the age of 10 years(44.0%). 8. In the group of tooth injury, tooth luxation(38.5%) showed the highest incidence followed by tooth fracture(33.2%) and tooth loss(17.1%). The common causes of tooth injury were fall, fight and traffic accident in order. 9. In infected patients group, the ratio of in-patients to out-patients was 1 : 1.28, Buccal(24,7%) and infraorbital space abscess(23.3%) showed the highest incidence. 10. The pain caused by dental caries(39.0%) and pericoronitis(26.6%) showed high incidence in the toothache group. 11. The high incidence was observed during third(34.0%) and fourth (24.5%) decades in TMJ dislocation group. 12. In the group of socket bleeding patients, 92% was post-operative hemorrhage and 8% was accompanied with other systemic hemorrhagic diseases.

• 대한소아치과학회지
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• 제38권3호
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• pp.290-295
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• 2011

치아형성 과정 중 치배 주위의 물리적 작용이나 대사 환경의 변화로 치아 발생은 영향을 받을 수 있다. 유치열기에 가해진 외상은 계승 영구치의 발생에 장애를 초래시킬 수 있는 가장 대표적인 물리적 요인으로 이로 인한 합병증으로 계승 영구치의 법랑질 변색 및 저형성증이 가장 흔히 발생하고 드물게 매복, 이소 맹출, 치근 형성 정지 및 치근 만곡 등이 나타난다. 본 증례에서는 만 6세 5개월의 여자 어린이 환자가 안면부 외상을 주소로 내원하여 상악 좌우 유중절치의 정출성 탈구, 상악 우측 유측절치의 함입성 탈구, 상악 좌측 유측절치의 구개측 측방 탈구로 진단되었고, 상악 치은부의 열상과 상악 전치부의 치조골 골절이 관찰되었다. 내원 당일 치과 응급실에서 동요도가 심한 상악 좌우 유중절치의 발치 후 치은 봉합술을 시행하였다. 24개월 정기 검진 중 방사선 사진 상에서 상악 좌,우측 측절치의 백악 법랑 경계(Cemento enamel junction, CEJ) 근방에 치근 만곡이 관찰되었고 상악 중절치 치근의 치관부 1/3부위에서 치근 형성이 정지되고 있는 양상이 관찰되었다. 치조골 골절이 어린이에서 흔하게 나타나는 외상의 유형은 아니나 본 증례에서와 같이 치근 발육이상 등 여러 합병증을 일으킬 수 있으므로 외상을 입은 환아에서 치조골 골절 여부에 대한 면밀한 검사 및 주기적인 검진은 예후 예측 및 향후 치료에 있어서 중요할 것이다.

• 대한소아치과학회지
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• 제40권1호
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• pp.53-59
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• 2013

유치 치근 파절의 치료는 정기 검진을 통해 관찰하거나 발치를 권유하고 있다. 특히 심한 동요도와 변위가 있는 경우 영구치 손상 가능성과 흡인의 위험성 때문에 주로 발치를 시행한다. 하지만 최근 재위치와 고정을 통한 보존적 치료가 새롭게 제시되고 있다. 이른 시기의 유전치 발치는 심미적 문제, 발음 저작 등의 기능적 문제, 공간 소실, 환아와 보호자의 심리 사회적인 문제 등 여러 가지 문제점들을 야기하므로 치근 파절된 유치를 유지하는 것만큼 좋은 치료는 없다. 이 증례 보고는 치근 파절을 보이는 두 증례의 진단, 치료, 평균 27개월의 정기 검진 자료를 토대로 심한 동요도와 변위가 있는 유치 치근 파절의 보존적인 치료 가능성을 제시하고자 하였다. 두 증례에서 발치 대신 재위치와 장기간의 레진 강선 고정을 시행하였고, 후속 영구치가 맹출 할 때까지 정기검진을 시행하였다. 정기검진과정 중에 동통, 치수괴사, 감염, 영구치 치배 변위, 맹출 이상 등의 부작용은 나타나지 않았다.

• 한국치위생학회지
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• 제22권4호
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• pp.225-230
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• 2022

Objectives: Patients with excessive tooth wear should first be diagnosed for the etiology of the tooth wear. Causes of tooth wear include bruxism, clenching, and taking medications for systemic diseases. After identifying the cause of tooth attrition, the final prosthesis should be restored with an appropriate vertical dimension. Methods: A 79-year-old man with worn out teeth desired a whole dental treatment. He was on medications for high blood pressure and asthma. The treatment proceeded with a consultation with a medical doctor. The medications for asthma evoked multiple teeth wear and a loss of the vertical dimension. After recovery of 3 mm of vertical dimension, 2 months of evaluation was followed by an interim prosthesis. Results: The increased vertical dimension caused no problem in function and esthetics, and the final restoration was performed with a full monolithic zirconia crown. Group function, adequate anterior guidance, and the occlusal plane were determined. Conclusions: After the final restoration, the patient was both esthetically and functionally satisfied, and a night guard splint was delivered to prevent prosthesis fracture. The patient was informed about the potential tooth wear associated with asthma drugs and educated to visit the clinic regularly.

• The Journal of Advanced Prosthodontics
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• 제4권1호
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• pp.37-42
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• 2012

PURPOSE. The influence of the modified process in the fiber-reinforced post and resin core foundation treatment on the fracture resistance and failure pattern of premolar was tested in this study. MATERIALS AND METHODS. Thirty-six human mandibular premolars were divided into 4 groups (n = 9). In group DCT, the quartz fibre post (D.T. Light-post) was cemented with resin cement (DUO-LINK) and a core foundation was formed with composite resin (LIGHT-CORE). In group DMO and DMT, resin cement (DUO-LINK) was used for post (D.T. Lightpost) cementation and core foundation; in group DMO, these procedures were performed simultaneously in one step, while DMT group was accomplished in separated two steps. In group LCT, the glass fiber post (LuxaPost) cementation and core foundation was accomplished with composite resin (LuxaCore-Dual) in separated procedures. Tooth were prepared with 2 mm ferrule and restored with nickel-chromium crowns. A static loading test was carried out and loads were applied to the buccal surface of the buccal cusp at a 45 degree inclination to the long axis of the tooth until failure occurred. The data were analyzed with MANOVA (${\alpha}$= .05). The failure pattern was observed and classified as either favorable (allowing repair) or unfavorable (not allowing repair). RESULTS. The mean fracture strength was highest in group DCT followed in descending order by groups DMO, DMT, and LCT. However, there were no significant differences in fracture strength between the groups. A higher prevalence of favorable fractures was detected in group DMT but there were no significant differences between the groups. CONCLUSION. The change of post or core foundation method does not appear to influence the fracture strength and failure patterns.

• Restorative Dentistry and Endodontics
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• 제42권1호
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• pp.1-8
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• 2017

Objectives: The purpose of this study was to evaluate the effect of adhesive luting on the fracture resistance of zirconia compared to that of a composite resin and a lithium disilicate glass ceramic. Materials and Methods: The specimens (dimension: $2mm{\times}2mm{\times}25mm$) of the composite resin, lithium disilicate glass ceramic, and yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) were prepared. These were then divided into nine groups: three non-luting groups, three non-adhesive luting groups, and three adhesive luting groups, for each restorative material. In the non-luting groups, specimens were placed on the bovine tooth without any luting agents. In the non-adhesive luting groups, only zinc phosphate cement was used for luting the specimen to the bovine tooth. In the adhesive luting groups, specimens were pretreated, and the adhesive luting procedure was performed using a self-adhesive resin cement. For all the groups, a flexural test was performed using universal testing machine, in which the fracture resistance was measured by recording the force at which the specimen was fractured. Results: The fracture resistance after adhesive luting increased by approximately 29% in the case of the composite resin, 26% in the case of the lithium disilicate glass ceramic, and only 2% in the case of Y-TZP as compared to non-adhesive luting. Conclusions: The fracture resistance of Y-TZP did not increased significantly after adhesive luting as compared to that of the composite resin and the lithium disilicate glass ceramic.

• The Journal of Advanced Prosthodontics
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• 제13권1호
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• pp.36-45
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• 2021

Purpose. To investigate the fracture resistance of monolithic CAD-CAM all-ceramic surveyed crowns with two different occlusal rest seat designs. Materials and Methods. Two maxillary first premolar were prepared for all-ceramic surveyed crowns with wide (2/3rd of buccolingual width of an unprepared tooth) or narrow (1/3rd of buccolingual width of an unprepared tooth) disto-occlusal rest seat (ORS) designs. Eighty monolithic CAD-CAM all-ceramic surveyed crowns were prepared and divided into 4 groups - Group CR, Composite resin material as a control; Group LDS, Lithium disilicate based material; Group ZIPS, zirconia-material (IPS ZirCAD); and Group ZLHT, zirconia- material (CeramillZolidht+). Crowns were cemented on an epoxy resin die with adhesive resin cement. The fracture resistance of crowns was tested with the universal machine. Univariate regression analysis was used. Results. The mean ± standard deviation of maximum failure force values varied from 3476.10 ± 285.97 N for the narrow ORS subgroup of group ZIPS to 687.89 ± 167.63 N for the wide ORS subgroup of group CR. The mean ± standard deviation of maximum force was 1075 ± 77.0 N for group CR, 1309.3 ± 283.9 N for group LDS, 3476.1 ± 285.97 N for group ZIPS, and 2666.7 ± 228.21 N for group ZLHT, with narrow occlusal rest seat design. The results of the intergroup comparison showed significant differences in fracture strength with various material groups and occlusal rest seat designs (P<.001). Conclusion. The zirconia-based all-ceramic surveyed crowns fractured at more than double the load of Lithium disilicate based crowns. The crowns with narrow base occlusal rest seat design had statistically significantly higher fracture resistance than surveyed crowns with wide occlusal rest seat design. The use of narrow occlusal rest seat design in CAD-CAM all ceramic surveyed crowns provides higher fracture resistance, and therefore narrow occlusal rest design can be used for providing esthetics with high strength.

• 한국생산제조학회지
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• 제20권3호
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• pp.284-291
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• 2011

Numerical experiments on biological interfacial layer, DEJ by finite element software ABAQUS have been conducted to study its fracture behavior including crack bridging / arresting characteristics in the model. Crack growth simulation has been carried out by numerical tool, XFEM, devoted to study cracks and discontinuities. The fracture toughness of DEJ has been estimated before and after crack bridging. The implications of bridging in numerical study of fracture behavior of DEJ-like biological interface have been discussed. It has been observed that the results provided by the numerical studies without proper accommodation of bridging phenomenon can mislead. This study can be helpful for understanding the DEJ-like biological interface in terms of its fracture toughness, an important material characteristics. This property of the material is an important measure that has to be taken care during design and manufacturing processes.

• 대한치과의사협회지
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• 제48권7호
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• pp.531-537
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• 2010

Intentional replantation is useful for failed cases of conventional dental treatment - including root canal treatment - to restore the tooth in question. Based on a recent study, it is relatively very successful; prognosis is good for a long period. On the other hand, a tooth that becomes an indication of intentional replantation is often severely weakened throughout several treatments. Moreover, with multi-rooted teeth, extracting without root fracture is difficult. Safe extraction that is free of coronal or root fracture is important, but little information is known as to a concrete, safe way of extraction. There are a few considerations for safe extraction. First, a tooth with orthodontic extrusion force is easier for extraction due to its increased mobility; it increases the amount of the periodontal ligament, which is essential for re-attachment. As a safe way of extraction, the use of physics forceps has been introduced recently; it minimizes damage to the gingiva and alveolar hone. This paper reports the good result of using atraumatic safe extraction via both orthodontic extrusion and physics forceps$^{(R)}$.

• 한국정밀공학회지
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• 제27권4호
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• pp.87-94
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• 2010

When occlusal force is applied to a tooth, stress concentration occurs on the dental cervical line. This study investigated to find the maximum force and strain of natural teeth using an Instron and strain gauges, comparing the strain of cervical enamel using finite element analysis(FEA). Tests were conducted with a mandibular first premolar applying the conditions of occlusion. Then, the FEA was processed with the same as conditions of the fracture test. The test showed that the maximum force, maximum compressive strain and maximum tensional strain was $278{\pm}26$ N, $0.668{\times}10^{-3}{\pm}0.678{\times}10^{-3}$ and $0.248{\times}10^{-3}{\pm}0.102{\times}10^{-3}$, respectively. It was found that six of eight measured strains were within the range of estimated strains by the FEA. Even though it was assumed that properties of FE models were isotropic, it could prove useful as a reference in understanding the tendency of dental strain.