• Restorative Dentistry and Endodontics
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• 제10권1호
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• pp.63-70
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• 1984

It was the purpose of this study to determine the galvanic current between a gold alloy inlay and four types of amalgam using the circuit through pulp chambers when the freshly extracted teeth with those restorations were brought into contact in a physiologic saline solution, and to investigate the effectiveness of cavity varnish or ammonated silver-nitrate on the surface of amalgam restoration in reducing galvanic current. The current was measured with current-to-voltage converter and recored on a physiograph 6630-257. The following results were obtained. 1. Generally, galvanic current decreased as the time elapsed. 2. Galvainc current decreased significantly in the first day and after then minimal change was observed until 30th day. 3. Initial galvanic current was 29.6 ${\mu}A$ in the cut amalgam and 24.5 ${\mu}A$ in Dispersalloy amalgam and after then the current was significantly decreased. 4. Initial galvanic current was 12.6 ${\mu}A$ in spherical amalgam (low copper amalgam) and 13.8 ${\mu}A$ in Tytin amalgam and the amount of change was lower in sperical amalgam and Tytin amalgam than that in lathe cut amalgam and Dispersalloy amalgam. 5. Painting ammoniated silver-nitrate or Copalite on the surface of amalgam resotration decreased initial galvanic current and ammoniated silver-nitrate is more effective in decreasing galvanic current than Copalite. 6. Galvanic current by contact between amalgam restoration and gold restoration increased abruptly and dropped rapidly becoming almost.

• 한국치위생학회지
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• 제14권3호
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• pp.425-430
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• 2014

Objectives : The purpose of this study is to investigate the correlation between amalgam restorations and urinary mercury levels in children for 1 year. Amalgam restoration has been widely used for over 200 years. But released mercury from amalgam can increase the concentration of mercury in the body. Methods : The subjects were 463 elementary school children. Oral examination, urine sampling, and questionnaire survey were performed at baseline and after 1 year. Results : Amalgam restoration increased the urinary mercury level to $0.55{\pm}0.13{\mu}g/g$ creatinine. In the regression analysis, variation of urinary mercury excretion were positively associated with amalgam surfaces and fish consumption. Conclusions : Small amount of mercury release from amalgam restoration was closely associated with increasing urinary mercury level.

• Restorative Dentistry and Endodontics
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• 제23권2호
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• pp.586-596
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• 1998

Amalgam is one of the most commonly used dental restoration material because of its convenience, economic and physical properties. But microleakage in the tooth and amalgam interface has been its major problem, and many efforts have been made to overcome this shortcoming. The purpose of this study is to compare the effect of various liners on microleakage of amalgam restoration. Cavities were prepared on the buccal or lingual surface of ninety sound, extracted human premolars and six different liners (Tubulitec$^{(R)}$, Superbond D-liner II Plus$^{(R)}$, Superbond D-liner II Plus$^{(R)}$ with polymer, Scotchbond Multipurpose Plus$^{(R)}$, Copalite$^{(R)}$, No liner) were unapplied according to manufacturer's instructions and amalgam had been condensed immediately. The specimens were thermocycled by dipping in methylene blue dye at $5^{\circ}C$ and $55^{\circ}C$ for 1500 cycles. The amalgam-tooth interface was examined under stereobinocular microscope and the dye penetration was scored. The results were as follows : 1. The Tubulitec$^{(R)}$ group showed less microleakage than no liner or Copalite$^{(R)}$ group (p<0.01). 2. The Tubulitec$^{(R)}$, Superbond D-liner II Plus$^{(R)}$, Superbond D-liner II Plus$^{(R)}$ with polymer and Scotch bond Multipurpose Plus$^{(R)}$ groups were not significantly different. 3. The Copalite$^{(R)}$ and Scotchbond Multipurpose Plus$^{(R)}$ groups were not significantly different. Using the polystyrene liner and resin liners under admixed type of high-copper amalgam restoration significantly reduced microleakage in the tooth-amalgam interface. Further clinical studies on polystyrene liner are recommended.

• Restorative Dentistry and Endodontics
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• 제6권1호
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• pp.109-114
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• 1980

Ease of manipulation, adequate mechanical properties, long years of experience and economical cost are the factors which have established amalgam as the most widely used material for dental restorations. But amalgam restoration may require replacement because of secondary caries, fracture, "fall-out", dimensional change, tarnish or corrosion etc.. These failures of amalgam restorations seem to arise from failures during operations rather than from the inherent shortcomings of the material itself or of the patient's mismanagement. It is anticipated that notonly number of analgam restoration, but failures will be increase after more extensive utilization of the medical insurance which began in 1977. Then authors think that it would be helpful for the development of better treatment in daily dental practice, to know the duration of amalgam restorations and the reasons for their replacement. The data for this survey was compiled from 2, 856 out-patients of the Department of Dentistry, Ewha Woman's University Hospital from January 1975 to December 1977. 260 cases among 1,718 fillings were studied, of which 205 cases both had a single reason for replacement and recognized the date of the previous filling. The results obtained were as follows; 1. Amalgam fillings were 58. 5 percent of all dental restorative materials. Of these, 15. 13 percent of the amalgam restorations had to be replaced. 2. The first reason for replacement of amalgam restorations was secondary caries (56.10%), the second was fracture (23.80%) and the third was "fall-out" (8.78%). 3. Among those amalgms requiring replacement, 52.2 percent had been in place less than 3 years, 70.7 percent within 5 years and 89.8 percent had been in place less than 10 years. Only 10.2 percent had been in place more than 10 years.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.339-352
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• 1996

Many dentists have been taken an interest in restoration of severly damaged teeth after endodontic treatment and it is a true that there are lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the effects of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper 1st premolar was severly damaged, and after the root canal therapy, two most common types of restoration were carried out ; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with amalgam core and gold crown. After restoration, in order to present the concentration of stress at internal portion of the tooth and the surrounding periodontal tissue, we doveloped a 2-dimensional finite element model of labiopalatal section, then loaded forces from 2 long perpendicular to the lingual incline of buccal ridge an the middle point, parallel to the long direction axis of tooth at the fossa-were applied. The analyzed results were as follows : 1. Stress of the normal first premolar was concentrated on the most weakest anatomical structure, that is, cervical area, and no stress on the bifurcated area of the canal. 2. Crown restoration after root canal therapy causes large stress concentration on the bifurcated area of the canal. This stress concentration has larger value in case of lateral movement of mandible, and there are decrease in the stress concentration compared with natural tooth. 3. Coronal-radicular amalgam restoration method transports more stress to the tooth structure than restoration using Para-Post. 4. There are more stress concentration around Para-Post in the case of lateral movement, and we have more favo rable result when restored with Para-Post. 5. Generally, stress in the lateral movement is larger than stress in the perpendicular load.

• 치과방사선
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• 제8권1호
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• pp.23-27
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• 1978

The purpose of the present investigation is to determine how frequently radiopaque zones are seen on standard intraoral films and to research some other things about radiopaque zones. This study obtained the following results: 1. According to the standard intraoral films of the charts that were kept at the Dept. of Oral Diagnosis in Seoul National University Hospital, radiopaque zones were found in the rate of 4.1% among 1150 cases of amalgam-restored teeth that were treated at least two years ago. 2. Out of teeth that possessed radiopaque zones, 38.3% had radiolucent area between amalgam restoration and radiopaque zone. 3. Out of teeth that possessed radiopaque zones, 36.2% had cement base between amalgam restoration and radiopaque zone. 4. Out of teeth that possessed radiopaque zones, no tooth had periapical radiolucency. 5. Radiopaque zones were found more frequently in the mandibular teeth than the maxillary teeth. 6. According to the result of direct x-ray taking of 50 teeth that were treated at least 2 years ago, 6% had radiopaque zone.

• Imaging Science in Dentistry
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• 제48권2호
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• pp.87-96
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• 2018

Purpose: The present study aimed to evaluate which of the following imaging methods best assessed misfit at the tooth-restoration interface: (1) bitewing radiographs, both conventional and digital, performed using a photostimulable phosphor plate (PSP) and a charge-coupled device (CCD) system; (2) panoramic radiographs, both conventional and digital; and (3) cone-beam computed tomography (CBCT). Materials and Methods: Forty healthy human molars with class I cavities were selected and divided into 4 groups according to the restoration that was applied: composite resin, composite resin with liner material to simulate misfit, dental amalgam, and dental amalgam with liner material to simulate misfit. Radiography and tomography were performed using the various imaging methods, and the resulting images were analyzed by 2 calibrated radiologists. The true presence or absence of misfit corresponding to an area of radiolucency in regions subjacent to the esthetic and metal restorations was validated with microscopy. The data were analyzed using a receiver operating characteristic (ROC) curve, and the scores were compared using the Cohen kappa coefficient. Results: For bitewing images, the digital systems (CCD and PSP) showed a higher area under the ROC curve (AUROC) for the evaluation of resin restorations, while the conventional images exhibited a larger AUROC for the evaluation of amalgam restorations. Conventional and digital panoramic radiographs did not yield good results for the evaluation of resin and amalgam restorations (P<.05). CBCT images exhibited good results for resin restorations(P>.05), but showed no discriminatory ability for amalgam restorations(P<.05). Conclusion: Bitewing radiographs (conventional or digital) should be the method of choice when assessing dental restoration misfit.

• 대한소아치과학회지
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• 제27권1호
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• pp.54-61
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• 2000

아말감은 널리 사용되어 온 대표적 치과재료이지만 치질과의 접착성이 없어 와동의 형태에 의해 유지되는 단점을 가진다. 아말감 수복물은 산화물에 의한 변연봉쇄가 일어나기 전까지 초기에 큰 미세누출을 보이며 수복초기에 이를 적절하게 예방하지 않으면 타액이나 미생물이 와동내에 침투하게 되고 이로 인해 수복 후의 과민반응, 충전물의 용해 및 파괴, 변연 변색과 2차 우식이 유발되어, 결과적으로 수복물의 수명이 단축되며 치수 병변이 발생될 수도 있다. 최근 기존 아말감 수복의 장점을 그대로 유지하면서 치질삭제를 줄이고 변연을 봉쇄하며 소와열구에 예방적 처치를 함께 할 수 있는 수복법이 제안되었는데 이를 이른바 sealed amalgam이라 한다. 이 술식은 예방적 확대 없이 병소만을 제거한 뒤 수복물 변연과 인접 소와열구에 치면열구전색재를 도포함으로서 소와열구의 예방적 충전은 물론 수복물 변연과 치질사이의 틈을 봉쇄하여 미세누출을 감소시킬 수 있다고 하였다. 이에 저자는 아말감 수복후 수복물의 마무리 처리와 전색재 적용시점을 달리 하여 sealed amalgam 수복과 기존의 아말감 수복과의 미세누출의 차이를 비교하고자 30개의 상, 하악 소구치를 준비하여 V급 와동을 소구치의 협, 설측에 형성하고 통상적 아말감 수복을 시행한 후 다음의 각 군으로 나누어 처리하였다. 제 1 군 : 24시간 후 연마 (대조군) 제 2 군 : 연마하지 않음, 즉시 전색재 적용 제 3 군 : 연마하지 않음, 열순환(thermocycling) 500회 후 전색재 적용 위의 처리 후 각 군을 $5^{\circ}C$와 $55^{\circ}C$의 온도변화를 30초씩 번갈아 주며 총 500회의 열순환을 실시한 후 1% methylene blue 용액에 침윤시켜서 100% 습도가 유지된 $37^{\circ}C$ 항온기에 24시간 보관하였다. 치아를 레진에 매몰한 후 협설측으로 치아 장축에 평행하게 절단하여 stereomicroscope를 사용해 색소침투도를 관찰하여 다음과 같은 결론을 얻었다. 1. 평균 미세누출은 연마하지 않고 바로 치면열구전색재를 도포한 2군이 가장 낮았고, 연마만 시행한 1군이 가장 높았다. 2. 실험군간의 미세누출 비교에서 연마만 시행한 1군은 2군에 비해 미세누출이 켰으며 통계적으로 유의성 있는 차이를 보였다(p<0.05). 3군은 1군보다 평균미세누출이 작았으나 통계적으로 유의한 차이가 없었다(p>0.05). 2군은 3군보다 평균 미세누출이 작았으나 통계적으로 유의한 차이가 없었다(p>0.05).

• Restorative Dentistry and Endodontics
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• 제34권6호
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• pp.467-476
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• 2009

본 연구의 목적은 아말감과 복합레진의 수복 과정과 수복 후 상아세관액의 흐름(dentinal fluid flow, DFF)을 측정하기 위함이다. 치근을 절제한 제 3 대구치를 자체 제작한 미세 유체 흐름 측정장치에 연결한 후 1급 와동을 형성하여 아말감과 복합레진 수복을 시행하였다. DFF의 측정은 와동 형성부터 수복 후 30분까지 연속적으로 이루어졌고, 수복 후 3, 7일에 재 측정하였다. 주수 하에 와동 형성 시 DFF는 inward로, 끝난 후에는 outward로 바뀌었다. 아말감 충전 시 DFF는 inward로 바뀌었고 충전 완료 후 미약한 outward DFF를 보였다. 복합레진 수복의 경우, 산 처리 후 수세와 건조 시 각각 inward와 outward DFF를 보였고 primer도포 후 공기 분사는 급격한 outward, 소수성 본딩제를 적용하는 단계에서는 outward 였던 DFF가 감소하여 0에 가까워지거나 약간 inward 흐름을 보였다. 접착제와 복합레진의 광중합은 급격한 inward의 DFF를 일으켰다. 수복 후 30분, 3일, 7일째 수복 재료에 따른 DFF의 감소에 통계적으로 유의한 차이는 없었다 (p>0.05).

• Restorative Dentistry and Endodontics
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• 제19권2호
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• pp.549-567
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• 1994

Restoration of severly damaged teeth after endodontic treatment had been an interest to many dentists, and it is a fact that there have been lots of studies about it. In these days, although we have used Para-Post, pins, threaded steel post, cast gold post and core, and so on, as a method of restoration frequently, it has been in controversy with the influence of them on the teeth and surrounding periodontal tissue. In this study, we assume that the crown of the upper incisor have severly damaged, so, after the root canal therapy, 4 types of restoration had been carried out; 1) coronal-radicular amalgam restoration, 2) after setting up the Para-Post, restore with composite resin core only, 3) after setting up the Para-Post; restore with amalgam core, then cover with the PPM crown 4) after setting up the Para-Post, restore with composite core, then cover with the PPM crown. After restoration, in order to observe the concentration of stress at internal portion of the teeth and the sourrounding periodontal tissue, developing a 2-dimensional finite element model of labiopalatal section, then loading forces from 3 direction - direction of 45 degrees from lingual side near the incisal edge, horizontal direction from labial height of contour, vertical direction at the incisal edge-were applied. The analyzed results were as follows: 1. Stress of the normal central incisor was concentrated on the dentin aroundpulp chamber, labiocervical portion of a tooth and root apex, but with the alveolar bone, in the case of load from the direction of 45 degrees from lingual side near the incisal edge showed remarkable concentration of stress: 2. Coronal-radicular amalgam technique -showed less concentration of stress on the root and surrounding periodontal tissue than the restoration with the Para-Post. 3. The von Mises equivalent stress on the Para-Post showed maximum value at root-core junction rather than both ends and model with PPM restoration with amalgam core showed the least concentration of stress. Only the force from horizontal direction showed large shear stress on internal portion of the root, root apex and alveolar bone. 4. PPM crown with composite core rarely showed the concentration of stress on root and periodontal tissue. 5. As for alveolar bone, remarkable shear stress was concentrated on labial and palatal side by horizontal load.