• The Journal of Advanced Prosthodontics
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• 제1권2호
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• pp.85-90
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• 2009

STATEMENT OF PROBLEM. Over the years, resin-bonded fixed partial dentures (RBFPDs) have gone through substantial development and refinement. Several studies examined the biomechanics of tooth preparation and framework design in relation to the success rate of RBFPDs and considered retention and resistance form essential for increase of clinical retention. However, these criteria required preparations to be more invasive, which violates not only the original intentions of the RBFPD, but may also have an adverse effect on retention due to loss of enamel, an important factor in bonding. PURPOSE. The object of this in vitro study was to compare the dislodgement resistance of the new types of RBFPDs, the conventional three-unit fixed partial denture, and conventional design of RBFPD (Maryland bridge). MATERIAL AND METHODS. Fifty resin mandibular left second premolars and second molars were prepared on dentiforms, according to the RBFPD design. After model fabrication (five group, n = 10), prostheses were fabricated and cemented with zinc phosphate cement. After cementation, the specimens were subjected to tensile loading at a cross head speed of 4 mm/min in a universal testing machine. The separation load was recorded and analyzed statistically using one-way analysis of variance followed by Duncan's multiple range test. RESULTS. Group V, the pin-retained RBFPDs, had the highest mean dislodgement resistance, whereas specimens of group II, the conventional RBFPDs, exhibited a significantly lower mean dislodgement resistance compared to the other 4 groups (P <.05). There were no significant differences between group I, III, and IV in terms of dislodgement resistance (P>.05). Group V had the highest mean MPa (N/$mm^2$) (P <.05). There was no significant difference between groups I, II, III and IV (P > .05). CONCLUSION. Within the limits of the design of this in vitro study, it was concluded that: 1. The modified RBFPDs which utilizes the original tooth undercuts and requires no tooth preparation, compared with the conventional design of RBFPDs, has significantly high dislodgement resistance (P < .05). 2. The modified RBFPDs which utilizes the original tooth undercuts and requires minimal tooth preparation, compared with the conventional FPDs, has significantly no difference in retention and dislodgement resistance)(P>.05). 3. The pin-retained FPDs showed a high dislodgement resistance compared to the conventional three-unit FPDs (P<.05).

• Journal of Periodontal and Implant Science
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• 제38권1호
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• pp.97-102
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• 2008

Purpose: Periodontal intrabony defects have great deal of importance since they contribute to the development of periodontal disease. Current treatment regimens for intrabony defects involve grafting of numerous bony materials, GTR using biocompatible barriers, and biomodification of root surface that will encourage the attachment of connective tissue. Xenograft using deproteinized bovine bone particles seems to be very convenient to adjust because it doesn't require any donor sites or imply the danger of cross infections. These particles are similar to human cancellous bone in structure and turned out to be effective in bone regeneration in vivo. We here represent the effectiveness of grafting deproteinized bovine bone particles in intrabony defect and furcation involvements that have various numbers of bony walls. Materials and methods: Open flap debridement was done to remove all root accretions and granulation tissue from the defects within persisting intrabony lesions demonstrating attachment loss of over 6mm even 3 months after nonsurgical periodontal therapy have been completed. Deproteinized bovine bone particles($BBP^{(R)}$, Oscotec, Seoul) was grafted in intrabony defects to encourage bone regeneration. Patients were instructed of mouthrinses with chlorohexidine-digluconate twice a day and to take antibiotics 2-3 times a day for 2 weeks. They were check-up regularly for oral hygiene performance and further development of disease. Probing depth, level of attachment and mobility were measured at baseline and 6 months after the surgery. The radiographic evidence of bone regenerations were also monitored at least for 6 months. Conclusion: In most cases, radio-opacities increased after 6 months. 2- and 3-wall defects showed greater improvements in pocket depth reduction when compared to 1-wall defects. Class I & II furcation involvements in mandibular molars demonstrated the similar results with acceptable pocket depth both horizontally and vertically comparable to other intrabony defects. Exact amount of bone gain could not be measured as the re-entry procedure has not been available. With in the limited data based on our clinical parameter to measure pocket depth reduction following $BBP^{(R)}$ grafts, it was comparable to the results observed following other regeneration techniques such as GTR.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제31권5호
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• pp.401-407
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• 2009

Purpose : This study was designed to evaluate the clinical aspect of cysts which arised in the oral and maxillofacial region. Patients and Methods : We reviewed clinical record, radiograph, histopathologic and operative report of 155 patients who had been diagnosed as cysts and treated at the department of oral and maxillofacial surgery in Chonnam National University Hospital from January 2003 to December 2008. Gender, age, classifiaction, anatomic distribution, clinical sign and symptoms, treatment, complications and recurrence rate were studied. Results : 1. Among 155 patients, the male patients(64.5%) were more than the female(35.5%). 2. The average age ofthe patients was 37.2 years(ranging from 5 to 79 years). 3. In pathologic classification, radicular cyst and dentigerous cyst were most common cysts, irrespective of 73 cases(48.3%) and 35 cases(23.2%). 4. The frequently involved cystic regions were followed as mandibular molars(38.1%), and maxillary incisors(30.2%). 5. The frequent sequence of clinical symptoms was edema(29.9%), no symptom(18.9%), tenderness(13.9%), pain(11.5%) and abscess(9.4%). 6. The most prevalent treatment was the combination operation, such as cyst enucleation with extraction or endodontic treatment of the causative tooth(76.8%) 7. Among 155 cases, 2 cases that were treated using enucleation method were recurred(1.3%).

• 치과방사선
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• 제26권2호
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• pp.91-107
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• 1996

The purpose of this study was to investigate effects of osteoporosis on extraction wound healing in the calcium deficient rat. In order to carry out this study, ten-week old Wistar strain rats weighing about 300 gms were selected. When the rats reached thirteen-week old, rats' mandibular first molars were removed. The rats were then divided into three groups: Group l(rats given a normal diet both before and after tooth extraction), Group 2(rats given a low calcium diet for three weeks before tooth extraction and a normal diet after tooth extraction), and Group 3(rats given a low calcium diet for three weeks before and after tooth extraction). The healing of extraction wounds, as assessed by microradiography, autoradiography, and histopathologic examination, were compared among these three groups. The obtained results were as follows : I. In Group 1, newly formed bone and active uptake of 45Ca around extraction wound were noted on the 3rd and the 7th day. On the 14th and the 21st day, the extraction wounds of this group showed the bone trabecular formation and active 4Ca uptake in the extraction wound and alveolar crest. The more prominent bone trabeculae with a less uptake of /sup 45/Ca were noted on the 42nd day. 2. In Group 2, newly formed bone and thinning of alveolar bone trabeculae with more extensive uptake of /sup 45/Ca than that in Group 1 were noted on the 3rd and the 7th day. On the 14th day, bone trabeculae were less thicker than that in Group 1. The prominent bone trabeculae in the extraction wounds and alveolar crest were noted on the 21st and the 42nd days. 3. In Group 3, newly formed bone was noted on the 3rd and the 7th day. Alveolar bone trabeculae and uptake of /sup 45/Ca were similar to that in Group 2. On the 14th and 21st day, bone trabeculae were less thicker than that in Group 2 and Group 3. The osteoporotic change with active uptake of /sup 45/Ca was markedly noted on the 42nd day.

• 대한장애인치과학회지
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• 제12권2호
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• pp.87-91
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• 2016

저자는 소하악증으로 인해 기도유지가 어려우며 섭식 장애로 인한 다발성 우식을 보이는 피에르 로빈 증후군 환아의 증례를 보고하는 바이다. 환자는 소하악증 및 구개열, 심방중격 결손, 새끼 손가락의 측만지증(clinodactyly), 외사시(exotropia) 등의 증상을 동반하고 있었으며, 신체 발육이 매우 저하된 상태로 섭식 장애로 인한 구강내 침식 및 다발성 우식의 소견을 보이고 있었다. 환아는 가벼운 자폐 증상을 가지고 있으며 어린 나이로 협조를 구하기가 어려웠고 광범위한 치료가 필요한 상황이었으며 의식하 진정법시 하악의 발육 저하로 인한 기도 확보의 어려움이 예상되었기에 전신마취하 치과치료를 시행하였다. 피에르 로빈 증후군은 기도유지의 어려움과 섭식 장애로 구강위생 관리에 불리한 조건을 가지고 있지만 나이가 듦에 따라 점차 정상적인 하악의 성장이 이루어지므로 행동조절에 의한 일상적인 치과 처치도 가능할 것이다.

• 대한소아치과학회지
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• 제40권2호
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• pp.133-140
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• 2013

주기성 호중구 감소증은 호중구의 수가 감소하였다가 다시 정상으로 회복되는 반응이 주기적으로 나타나는 혈액질환이다. 임상적 증상으로 발열, 실신, 두통 등이 있으며 구강 내 증상으로 동통성 연조직 궤양이 특징적인데 특히 입술, 혀, 협점막, 치은이 흔하게 이환 된다. 또한, 치조골 파괴를 동반한 급진성 치주조직 상실을 보이기도 한다. 본 증례의 환아는 4세 1개월의 남아로서 잇몸이 붓고 이가 흔들린다는 것을 주소로 본과에 내원하였다. 환아는 주기성 호중구 감소증 환자로서 하악 전치부 5개 치아를 제외한 모든 유치에 우식이 있었으며 동요를 보이는 하악 좌 우 제1유구치의 국소적 치조골 소실을 확인할 수 있었다. 환아는 주기성 호중구 감소증에 기인한 광범위한 치아우식증, 치은염, 국소적 치주염으로 진단되었고 치료를 시행하였다. 주기성 호중구 감소증 환자에게는 정기적인 구강위생관리와 함께 치아우식, 치은염에 대한 시기적절한 치료가 필요하며 특히 어린 환자들에 있어서 영구치열 형성에 장애가 발생하지 않도록 조기에 개입을 하는 것이 중요하다.

• 구강회복응용과학지
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• 제24권4호
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• pp.371-379
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• 2008

본 연구의 목적은 안정 시, 임프란트 보철물과 자연치 사이의 인접치간 접촉강도를 평가하는 것이다. 좌측 상악 또는 하악 제2대구치에 단독으로 임프란트가 식립되어 보철물이 장착되어 있는 20명의 피험자를 임프란트 군으로, 좌측 상하악 제1대구치와 제2대구치 사이의 인접부위에 수복물이 없는 10명의 피험자를 대조군으로 나누어 교합력이 작용하지 않는 안정상태에서 인접치간 접촉강도를 평가하였다. 자연치 사이의 인접치간 접촉강도가 전반적으로 높게 나타났고, 특히 하악에서는 통계적으로 유의한 차이를 보였다. 임프란트 보철물에 있어서 인접치간 접촉을 좀 더 강하게 부여할 필요가 있음이 시사되었고 또한 자연치아와 임프란트 보철물사이의 경시적 변화에 따른 인접접촉강도의 변화를 평가할 필요가 있음이 시사되었다.

• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.337-345
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• 1999

The purpose of this study was to compare the shape of root canal after instrumentation with some engine driven NiTi files. Thirty narrow and curved canals(15-35 degree) of mesial canals of extracted human mandibular first molars were divided into three groups. Group 1: After radicular access with Gates Glidden drill, apical shaping using step back method with Flexo file Group 2: After radicular access with Gates Glidden drill, apical shaping with Profile .04 Group 3: Canal shaping with GT file and Profile .04. Using modified Bramante technique, the root was sectioned at 2 mm from apical foramen, height of curvature, 2 mm from canal orifice. Canal centering ratio, amount of transport, amount of dentin removed, shape of canal were measured and statistical analysis is done using SPSS Program V 7.5. The results were as follows: 1. Canal centering ratio of group 3 was the lowest at coronal part, but there was no statistical difference. Centering ratio of group 2 was the lowest at curve part, and there was statistical difference between group 1(P<0.05). Centering ratio of group 2 was the lowest at apical part, but there was no statistic difference. 2. Amount of transport of group 3 was the lowest at coronal part, but there was no statistical difference. Amount of transport of group 2 was the lowest at curve part, and there was statistical difference between group 1(P<0.05). Amount of transport of group 3 was the lowest at apical part, and there was statistical difference between group 1 and group 2, group 1 and group 3(P<0.05). 3. Amount of dentin removed of group 3 was the lowest at coronal part, bur there was no statistical difference. Amount of dentin removed of group 2 was the lowest at curve part, but there was no statistical difference. Amount of dentin removed or group 2 was the lowest at apical part, and there was statistical difference between group 1 and group 2, group 1 and group 3(P<0.05). 4. The shape of the canals after instrumentation varied among the groups. The majority of canals at coronal and curve part for group 1 were round in shape(7 in 10), those at apical part were oval(8 in 10). The majority of canals at coronal part for group 2 were round in shape(7 in 10) and there was no difference in the number of shape at other part. There was no difference in the number of shape at every part for group 3. As above results, NiTi rotary instrumentation showed a trend to remain more centered in the canal than SS file instrumentation. At using NiTi file, coronal shaping with Gates Glidden drill was not statistically different from shaping with GT file. But shaping with GT file showed tapered canals, so it may be said that shaping with GT file is a safe and valuable instrumentation method.

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.780-788
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• 1995

The purpose of this study was to compare the apical seal following root canal shaping by different methods. From fourty extracted mandibular 1st and 2nd molars, fourty mesial roots whose canals have some degree of curvature were selected. The mesiobuccal root portion including mesiobuccal portion of a crown was sectioned in each molar. After access cavity preparation for the mesiobuccal canal, working length was determined with # 10 K-file. The sectioned roots were implanted in acrylic resin block and randomly divided into four groups. The canals of group I were shaped by step-down/balanced force, group II by stepdown/step-back, group III by step-back and group IV by conventional method. All of the shaped canals were obturated by Thermafil method and access cavities were filled with IRM. The roots were removed from acrylic resin block and placed in 100 % humidity for 7days. Except the root surfaces of apical 2mm, the root surfaces were nail-varnished 3 times. After the roots were placed in 700 torr vacuum pressure for 15 minutes, they were immersed in 2% methylene blue solution for 4 days. Nail varnishes were removed with acetone. After that, the roots were decalcified in 5 % nitric acid and dehydrated with alcohol series. Transparent specimens were made by methyl salicylate and the quality of apical seal was assessed by measuring the leakage linearly. The results were as follows. 1. The leakage in canals shaped by step-down/balanced force method was significantly less than that in canals shaped by step-back method(P<0.05) and was less but not statistically than that in canals shaped by step-down/step-back method (P>0.05). 2. The leakage in canals shaped by step-down/step-back method was less than that in canals shaped by step-back method, but there was no statistical significance(P>0.05). 3. The leakage in canals shaped by conventional method was significantly more than that in canals shaped by step-down/balanced force, step-down/step-back and step-back method (P<0.05).

• Restorative Dentistry and Endodontics
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• 제20권2호
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• pp.768-779
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• 1995

This study was performed to investigate the effect of root canal shaping techniques on the change of the shape of prepared root canal. 40 mesiobuccal canals of recently extracted mandibular 1st and 2nd molars were divided into 4 groups and shaped by step-down/balanced force technique, step-down/step-back technique, step-back technique and conventional technique respectively. The change of the shape of root canal was traced by superimposing the radiographs obtained before and after shaping of each root canal. The results were as follows. 1. By the experimented techniques except conventional technique, the root canals were more shaped in convex side of apical area and in concave side of most curved and coronal area than in the other sides(P<0.05). By conventional technique, the root canals were more shaped in convex side than in convave side from apex to orifice(P<0.05). 2. By step-down/balanced force technique, the cancave sides at C and D points of proximal view and C point of clinical view were more shaped than the convex side(P<0.05). Through the entire canal, the concave side was more shaped than the convex side in proximal view(P<0.01). But there was no statistical difference between both sides in clinical view. 3. By step-down/step-back technique, the change of root canal shape was not statistically different in concave and convex sides at each point of both views(P>0.05). And through the entire canal in proximal view, there was no statistical difference in shaping percentage between both sides. But through the entire canal in clinical view, the concave side was more shaped than the convex side(P<0.1). 4. By step-back technique, the convex side at B point of clinical more shaped than the other sides(P<0.05). Through the entire canal in proximal and clinical views, there was no statistical difference in shaping percentage between both sides. 5. Comparing the total shaping percentage among techniques, that in conventional technique was the greatest numerically, and followed by the percentages in step-down/step-back, step-down/balanced force and step-back technique. But, in proximal view, shaping percentages were not statistically different among techniques(P>0.05, ANOVA test). In clinical view, shaping percentages in step-back and conventional techniques were statistically different(P<0.01, ANOVA test). * Proximal view: radiograph taken in mesiodistal direction. * Clincal view: radiograph taken in faciolingual direction. A point : 1mm point from radiographic apex B point : center point between A and C points C point : most curved point of root canal D point : center point between C point and canal oriffice.