OBJECTIVETo evaluate the efficacy of flowable composite resin(FCR) as stress-absorbing liners in Class I cavity restorations in vitro.

METHODSThirty Class I cavities of 4 mm in diameter and 2 mm in depth were prepared in polycarbonate (PC) plates and divided into three groups, ten each. After application of an adhesive, cavities in each group were restored using one of the following methods: A: restored with Charisma without any lining of FCR; B: lined with Revolution Formula 2 twice before restoration with Charisma; C: lined with Teric Flow twice before restoration with Charisma. All cavities were observed under a photoelastic microscope and photoelastic images were recorded at 3 min and 24 h after curing and the shrinkage stresses on the cavity wall were calculated. The polymerization shrinkage(v%) of the three composite resins was measured using bonded discs method and their elastic moduli were measured according to ISO standard.

RESULTSThe shrinkage stresses at 3 min and 24 h of the three methods were as follows,A: (4.93 ± 0.28), (5.87 ± 0.40) MPa, B: (4.90 ± 0.30), (5.84 ± 0.33) MPa, and C: (4.76 ± 0.28),(5.83 ± 0.37) MPa.No significant difference was found in results among different groups. The polymerization shrinkage(v%) in group A,B, and C were (2.63 ± 0.04)%, (4.56 ± 0.06)%, and (3.98 ± 0.02)%. The elastic modulus in group A, B, and C were (9.59 ± 0.65), (4.25 ± 0.51), and (5.41 ± 0.79) GPa.

CONCLUSIONSUnder present study condition, using a FCR as stress-absorbing liner under composite resin restoration does not significantly decrease the polymerization shrinkage stresses at the cavity wall.

Composite Resins ; chemistry ; Dental Cavity Lining ; Dental Restoration, Permanent ; methods ; Dental Stress Analysis ; Materials Testing ; Polymerization

STATEMENT OF THE PROBLEM: Recent data regarding the effects the cement type and abutment heights on the retentive force of a prosthetic crown are inconsistent and unable to suggest clinical guidelines. PURPOSE OF THE STUDY: This study evaluated the effects of different types of temporary cements and abutment heights on the retentive strength of cement-retained implant-supported prostheses. MATERIALS AND METHODS: Prefabricated implant abutments, 4 mm in diameter, 8degrees taper per side, and light chamfer margins, were used. The abutment heights of the implants were 4 mm, 5.5 mm and 7 mm. Seven specimens of a single crown similar to a first premolar were fabricated. Six commercially available temporary cements, TempBond, TempBond NE, Cavitec, Procem, Dycal, and IRM, were used in this study. Twenty-four hours after cementation, the retentive strengths were measured using a universal testing machine with a crosshead speed of 0.5 mm/min. The cementation procedures were repeated 3 times. The data was analyzed using two-way analysis of variance and a Tukey test (alpha=0.05). RESULTS: The tensile bond strength ranged from 1.76 kg to 19.98 kg. The lowest tensile strengths were similar in the TempBond and Cavitec agents. Dycal showed the highest tensile bond strength (P<0.01). More force was required to remove the crowns cemented to the long abutments (P<0.05). CONCLUSION: TempBond and Cavitec agents showed the lowest mean tensile bond strength. The Dycal agent showed more than double the tensile bond strength of the TempBond agent.
Bicuspid ; Calcium Hydroxide ; Cementation ; Collodion ; Crowns ; Dental Abutments ; Dental Cavity Lining ; Dental Cements ; Dental Implantation ; Eugenol ; Light ; Minerals ; Prostheses and Implants ; Tensile Strength ; Zinc Oxide

In this study, I am planning to analyze the contents of Simple formula in Treasured Mirror of Eastern Medicine (TM), and then find out the historical implication of medical science. Simple formula is a prescription that is consisted of a single or three to four kinds of medicines, and this does not follow typical control principles such as 'sovereign, minister, assistant and courier'. While simple formulas are often built after major formulas, TM placed simple formulas to an end of each classified item. It is difficult to find a similar compilation style as that of Simple formula among similar volumes of medical books during the same period of TM. Thus, it can be assumed that TM included simple formulas for special purposes or reasons which are deemed as an important factor in stipulating the features of TM. The tradition of Simple formula, using medicinal herbs which can be easily acquired and trying to make an effect with a small number of herbs, had existed before Goryeo Dynasty. Introduced by Emergency Prescriptions from the Countryside and Samhwaja's Formulary from the Countryside, the tradition of Simple formula is succeeded by Compendium of Prescriptions from the Countryside, and after a while, it is synthetically arranged and recognized through Simple formula of TM. By analyzing simple formulas of TM, I could find out the followings. First, in simple formulas of TM, in which the components are the number of medicinal herbs, the name of prescription, and their application, should be understood as a simply consisted prescription rather than single medicine formulas. Second, simple formulas of TM are 2,001 in total, and are organized in most items. Third, although simple formulas cite a number of formulary, it shows a high degree of dependence to Classified Emergency Materia Medica. This shows that simple formulas that are structured to use medicine according to symptoms based on the effect of each medicinal herb, without understanding or dialectic process of syndrome differentiation. Fourth, while the part of medicinal herbs, Decoction section, focuses on listing the information of each medicinal herb, simple formulas introduce effect, dose, volume and even a mix with other medicinal herbs and an application of them. Therefore, a simple formula evaluates single medicinal herb as a sort of prescription. Fifth, more than half of 33 kinds of medicinal herbs, which are used more than 11 times in simple formulas of TM, are easy to get around the village, and their Korean names of Materia Medica from the Countryside are possible to be seen in Decoction section. However, the fact that Materia Medica from China such as Coptics chinensis and Realgar is included in simple formulas means that they are not limited to Materia Medica from the Countryside, and some of Materia Medica from China were not difficult to be procured in the time of publication of TM. Specific purpose of publishing simple formulas is not written separately. However, through the king's command of King Seonjo (1552-1608) in introduction, the active containing of folk prescriptions, and the emphasis of medicinal herb's volume using simple formulas, it is assumed that the Chosun government at that time tried to provide friendly and practical medical information with simple formulas, to collect and formulate private medical experiences in order to expand their extension of medical information, and to maximize the effect of treatment. The compilation system like TM was highly regarded but was also the target of criticism. In particular, King Jeongjo (1752-1800) criticized the complicatedness of TM and deleted information related to simple formulas through government compilation medical texts such as Explanation of Subtleties for the People's Longevity, New Edition on Universal Relife. However, simple formulas which were not composed of many medicinal herbs could be useful way for treating people who did not have professional medical knowledge and did not have a large range of herbs. In actuality, Secret Works of Universal Benefit, the representative compilation of civil medicinal text which was published after TM included information related to simple formulas, and in Records for rural life of Chosun gentlemen, the framework of simple formulas of TM was maintained and is filled with a vast amount of information. Furthermore, cases of utilizing simple formulas are included in the U-Jam's miscellaneous writings which is a clinical record. In Simple formulas of TM, private medical experiences at the time of Chosun are written first, then recognized by the experts, and finally returned to the public. Although the purpose and the target of these simple formulas publication are not clearly known, it is easy found, does not require any advanced medical knowledge, and above all, the people must have welcomed to the supply of economic simple formulas. Therefore, simple formulas show an aspect of TM, as a medical book for public.
Arsenicals ; Butanones ; China ; Collodion ; Cyclooxygenase 2 Inhibitors ; Dental Cavity Lining ; Emergencies ; Hypogonadism ; Longevity ; Materia Medica ; Mitochondrial Diseases ; Ophthalmoplegia ; Plants, Medicinal ; Prescriptions ; Publications ; Sulfides

Medical knowledge in India began to be introduced to China in earliest from the Later Han Dynasty period to the times of Wei-Qin and South & North Dynasties. This is proved by many Buddhist medical books appeared in those days. Of the contents of Indian medicine, the theory of four major elements affected Chinese medicine more than did the theory of body fluids. Based on the theory of four major elements that was began to be introduced in Fu shuo fu yi jing, an attempt to establish a new medical system was made in Zhou hou bai yifang written by Tao Hong-jing and Sun Si-miao who tried to develop etiology further but could not achieve any great outcomes. Unlike the foregoing situation, Indian medicine aroused a large echo in China in the field of ophthalmology with ophthalmological knowledge mentioned in Susrutasamhita and 'Jin-zhen-shu'(cataract couching) introduced as a surgical treatment of cataract. The Susrutasamhita which is one of the three major texts of Indian medicine contains additional information on surgical operations not introduced in the Carakasamhita. The technique of cataract surgery was particularly popular in the Tang and Song dynasty periods in China under the name Long shu pu sa yan lun(The Ophthalmological Treatise of Bodhisattva Nagarjuna) or Long shu lun and was even designated as a subject to educate medical officers. While the original text of Long shu pu sa yan lun was not handed down, the first testimony that show the trace of the introduction of this text into China was the Tian zhu jing lun yan mentioned in Wai tai mi yao(Arcane Essential from the Imperial Library) written by Wang Tao. Long shang dao ren who was mentioned as the compiler of the book is assumed to be Long shu. Although Tian zhu jing lun yan introduced anatomical knowledge about the eyeball that could have not been in the traditional Chinese medicine, this book has only limited quantity of information in this regard. Thereafter, Tai ping sheng hui fang(Holy Prescriptions for Universal Relief) compiled by a national agency at the beginning of the Song Dynasty period introduced Long shu pu sa yan lun without clear indication of the reference. Contemporary with this book, many ophthalmological books such as Mi chuan yan ke long mu lun(Longmu's Ophthalmology Secretly Handed Down) were published. As Chinese culture was spreading out into surrounding countries, medical knowledge was also introduced to Korean peninsula and Japan. The ophthalmological knowledge contained in Long shu pu sa yan lun was also reflected and some parts of it were introduced in I shin bo in Japan. Based on the policy decision of King Sejong, the fourth king of Joseon Dynasty, large scaled promoting projects of medical knowledge was established. It is notable that the Ui bang ryu chwi compiled as a result of the synthesis of the medical treatises available at that time initiated by King Sejong contained a considerable part of Long shu pu sa yan lun in reedited form that had already passed into oblivion in China. The intellectuals in Joseon Dynasty who participated in the compilation of Ui bang ryu chwi not only indicated that Long shu pu sa yan lun was a medical text published in the times of Wei-Qin and South & North Dynasties in China but also clearly indicated the textual reference and left the original text for later generation without modifying the contents. According to the Ui bang ryu chwi, the Long shu pu sa yan lun indicated that the core causes of eye diseases were heat, winds, and three body fluids(tridosa) and contained the analyses of symptoms, related treatments, and several analyses of wrong treatments. In addition, Long shu pu sa yan lun explained diverse eye diseases through more than 30 medical treatments. In particular, this book accurately described golden needle acupuncture for treatment of a Nei-zhang understood to be cataract. Therefore, this book is a significant textual record in the history of ophthalmological medicine in East Asia. Along with the golden needle acupuncture which is a method of removing the crystalline lens in which white turbidity occurred by stabbing the eyeball with a needle, traces of Indian medicine that had been already lost in China were clearly indicated in Long shu pu sa yan lun kept in the Ui bang ryu chwi. In particular, the book indicates that the eyes were directly correlated with the brain and that to treat the internal disorder, treating the brain that lost stability due to heat and bodily wind was indispensable; these are the traces of Indian influence. This textual source demonstrates a case of knowledge exchange in field of medicine with concrete cases of the encounter and clash between the standpoints of understanding human body.
Acupuncture ; Asian Continental Ancestry Group ; Brain ; Cataract ; China ; Collodion ; Dental Cavity Lining ; European Continental Ancestry Group ; Eye ; Eye Diseases ; Hand ; Hot Temperature ; Human Body ; Humans ; India ; Insecticides ; Japan ; Lens, Crystalline ; Medicine, Chinese Traditional ; Needles ; Nitriles ; Ophthalmology ; Prescriptions ; Pyrethrins ; Singing ; Solar System ; Troleandomycin ; Wind