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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Restorative Dentistry and Endodontics
Journal Basic Information
Journal DOI :
The Korean Academy of Conservative Dentistry
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Volume & Issues
Volume 24, Issue 4 - Dec 1999
Volume 24, Issue 3 - Sep 1999
Volume 24, Issue 2 - Jun 1999
Volume 24, Issue 1 - Apr 1999
Selecting the target year
VARIATION OF UREASE GENES(ureC) FROM Streptococcus salivarius
Choi, Hye-Jin ; Lee, Jin-Yong ; Choi, Ho-Young ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 535~545
Crease of Streptococcus salivarius is believed to play a critical role in bacterial ecology and pH homeostasis in the mouth, and consequently affect the pathogenesis of dental caries and periodontal diseases. Expression of the urease gene is greatly enhanced by low p. f. excess of Carbohydrate, and faster growth. It was observed that urease activity of the strains of S. salivarius that exhibited no of low urease activity was not increased even in low pH condition. In this study, it was hypothesized that the urease gene of the strains is absent, defected, or greatly changed by genetic combination. In order to prove this hypothesis, chromosomes were obtained from 28 S. salivarius strains which had been isolated from normal teeth and carious lesions, subjected to polymerase chain reaction (PCR) using primers encoding highly conserved sequence from ureC, and then the obtained PCR products were compared. The results were as follows: 1. After PCR the strains generated either one of 0.54- and 1.3-kbp PCR products, or none. 2. All 16 strains having a higher urease activity(<50
) produced 0.54-kbp PCR products. 3. Twelve strains without urease activity and with a lower urease activity(<50
) yield either one of 0.54 and 1.3-kbp PCR products, or none. 4. The DNA sequence of the 0.54-kbp PCR product (pCAP-0.54) exhibited 95% identity to the ureC of S. salivarus 57.I; 30bp were found to be different, which led to difference of only 2 amino acids in the sequence. 5. The DNA sequence of the 1.3-kbp PCR product(pCAP-1.3) was found to be highly homologous to the aminopeptidase C gene of Streptococcus thermophilus. Overall results indicate that there are considerable variations of the urease genes from S. salivarus strains and the variations may affect the uncolytic activity of the bacteria directly of indirectly.
SHEAR BOND STREGNTHS OF ONE-BOTTLE DENTIN ABHESIVE SYSTEMS
Cho, Byeong-Hoon ; Lim, Sung-Sam ; Kwon, Hyuck-Choon ; Um, Chung-Moon ; Son, Ho-Hyun ; Bae, Kwang-Sik ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 546~553
In Older to evaluate the effectiveness of 'One-bottle dentin adhesive system', the shear bond strengths of two fourth generation dentin adhesive systems and two One-bottle systems to the occlusal dentin of the freshly extracted third molars were measured by the regulation of the ISO TR 11405. The fourth generation dentin adhesive systems used in this study were Scotchbond Multi-Purpose Plus and All-Bond 2, and the One-bottle systems were Single Bond and One-Step. The effects of the thickness of hybrid layer and adhesive layer, the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule were analyzed as the contributing factors of the shear bond strength of dentin bonding systems from the Scanning Electron Microscopic images. The results were as follows: 1. The shear bond strengths of Scotchbond Multi-Purpose, All-Bond 2, and Single Bond were 16.98
3.40 MPa, 15.10
2.77 MPa and 15.05
3.18 MPa, respectively. There were no statistical differences(p>0.05). 2. But, the shear bond strength of One-Step were significantly lower than those of the other groups (11.81
1.95 MPa, p<0.05). 3. The thicknesses of hybrid layer and adhesive layer of One-Step were significantly thinner than those of the other groups(p<0.05). The differences of the diameter of resin tag(p=0.0685) and the ratio between the diameter of resin tag and that of dentinal tubule(p=0.2401) were not significant among all the material groups. 4. The thickness of hybrid layer and adhesive layer might be considered as contributing factors of the she at bond strengths of dentin bonding systems, but the diameter of resin tag and the ratio between the diameter of resin tag and that of dentinal tubule might not.
A STUDY OF THE EFFECTS OF AUCUBIN ON THE PULP TISSUE AFTER PULPOTOMY IN DOGS
Baek, Seung-Ho ; Lee, Sung-Woo ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 554~559
Aucubin, an iridoid glucoside isolated from Aucuba japonica, has pharmacological effects such as antimicrobial effect, liver protective function and inhibition of liver RNA and protein biosynthesis, etc. This study was performed to observe the effect of aucubin on the pulp tissue after pulpotomy. Aucubin was converted to aucubinogenin as an active form by
-glucosidase. In 3 Mongrel dogs, the pulps were mechanically exposed with a sterile round bur and excised with sterile excavator. After bleeding control, aucubin was applied on remaining pulp tissues and then they were sealed with IRM in experimental group. In control group,
powder was applied on remaining pulp tissues and then they were sealed with IRM. After interval of 1 and 12 weeks, the dogs were sacrificed. The teeth were prepared for histologic evaluation and examined by light microscope. Aucubin 1 week group showed that mild inflammation and vascular congestion in most of the specimen. More various degree of inflammation was found in experimental group than in control group. Premature calcified mass were found in the both 1 weeks groups. Continuous well-formed dentin bridge was found in both 12 weeks groups. Collectively, this study suggests that the possibility of aucubin as a medicament after pulpotomy.
MEASUREMENT OF PULPAL BLOOD FLOW USING A LASER DOPPLER FLOWMETER
Ban, Tae-Whan ; Lee, Jae-Sang ; Kim, Sung-Kyo ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 560~569
Blood supply rather than nerve supply implies pulp vitality. To evaluate pulp vitality clinically, electric pulp test and thermal test which are based on sensory nerve response have been used in addition to many auxiliary data such as past dental history, visual inspection, radiographic examination, percussion, palpation and transillumination test. However, reactivity of the nerves to the stimulation is not synonymous with normalcy. Therefore measurement of pulpal blood flow using a laser Doppler flowmeter became a new trial to test the pulp vitality. The purpose of the present study was to evaluate normal pulpal blood flow level of maxillary teeth in adult to provide a guideline in determining the vitality of dental pulp. Pulpal blood flow was measured in maxillary central and lateral incisors, canines, first and second premolars and first molars of seventy nine adults of 22 - 30 years old using a laser Doppler flowmeter (PeriFlux 4001, Perimed Co., Stockholm, Sweden, 780 nm infrared laser, 1mW). For directly-made splints, silicone rubber impressions were taken directly from the mouth. For indirectly-made splints, alginate impressions were taken from the mouth and stone cast were made. After making depressions on the buccal surfaces of the cast teeth to indicate the hole positions, second impressions with vinyl polysyloxane putty were taken from the cast. Holes for the laser probes were made at the putty impressions 4mm above the gingival level. Laser probe (PF416 dental probe, 1.5mm) was inserted in the prepared hole and the splint was set in the mouth. After 10 minutes of patient relaxing, pulpal blood flow was recorded for 5 minutes on each tooth. The recorded flow was saved in the computer and calculated with a software 'Perisoft' version 5.1. Pulpal blood flow was also recorded in six teeth of five individuals with no response to electric pulp test and cold test, with periapical radiolucency, or with history of root canal treatment to compare with nonvital teeth. The difference between the mean flow values of each group of teeth were analyzed using one-way ANOVA and Duncan's Multiple Range test. The results were as follows: 1. The average pulpal blood flow values of all the tested teeth of each location were between 9 - 16 Perfusion Unit. Pulpal blood flow value was highest in maxillary lateral incisors, followed by first premolars, second premolars, canines, central incisors, and then first molars (p<0.01). 2. In six anterior teeth, indirectly-made splint group showed higher pulpal blood flow values than directly-made splint group (p<0.01). In posterior teeth, however, there was no significant flow value difference between directly-made splint group and indirectly-made splint one (p>0.05). 3. Teeth with vital pulps showed higher signal values than teeth with nonvital pulps (p<0.01), and the flow photographs showed heartbeat-synchronous fluctuations and vasomotions, while those were absent in non vital tooth.
BOND STRENGTH AND MICROLEAKAGE IN RESIN BONDING TO TOOTH STRUCTURE
Kim, Jin-Hee ; Park, Jeong-Won ; Park, Jin-Hoon ; Kim, Sung-Kyo ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 570~577
Intuitively, higher bond strengths should result in less leakage. However, the relationship between bond strengths and microleakage value is complex and not clearly understood. The purpose of this study was to evaluate the relationship between tensile bond strengths and microleakage values in the same restorations to understand the behavior of resin bonding to tooth structure. One-hundred and twenty enamel or dentin specimens from freshly extracted bovine mandibular incisors were used. The specimen was treated with 32% phosphoric acid for 15 seconds and rinsed for 20 seconds. the teeth were divided into four groups by means of wet bonding technique or dry bonding. One-Step
adhesive were applied to the specimen. The specimens were immersed in 2% methylene blue solution for 7 days, and tensile bond strength and microleakage were measured. The results were as follows: 1. Significant negative correlation was found between bond strengths and micro leakage values. Hence, higher bond strengths seem to be associated with lower microleakage, and vice versa (r=-0 50, p<0.05). 2. The Enamel/Wet group showed significantly higher bond strength than Enamel/Dry one, and Dentin/Wet group showed higher strength than Dentin/Dry one (p<0.05). 3. Microleakage was significantly less ill wet bonding than in dry one at dentin (p<0.05), however, there was no significant difference between wet and dry bonding at enamel (p>0.05).
ACCURACY OF TRI AUTO ZX
IN LOCATING APICAL FORAMEN WITH ROTARY FILE
Park, Jeong-Won ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 578~584
The purpose of this experiment was to determine: (1) the safe automatic apical reverse setting that prevents overinstrumentation of the root canal, using Tri Auto ZX
and (2) the effect of various irrigant on such instrumentation. The instrumentation was carried out with the automatic apical reverse setting of 0.5, 1.0, 1.5, and 2.0. The root canal irrigants used in usual manner were normal saline(0.9%), NaOCl(2.5%), and RC Prep
. For each reverse setting and each irrigant, ten teeth were used with the total of 120 teeth. The distance between the file tip and the apical constriction was determined by stereomicroscope using the point that the file began to rotate in reverse direction. When the reverse setting mode was set to 0.5, 18 of 30 were overinstrumented. If these were discriminated by irrigant, 10 of 6 with 0.9% saline, 10 of 6 with NaOCl, and 10 of 6 with RC Prep
has the file tip located 0.57
0.39mm, and 0.26
0.25mm beyond the apical constriction respectively. In 1.0 setting 15 of 29 were over the apical constriction, and the distribution was 6 in saline, 5 in NaOCl, and 4 in RC Prep
. The mean distance over the apical constriction was 0.28
0.13mm with saline, 0.75
0.61mm with NaOCl, and 0.25
0.17mm with RC Prep
. When the autoatic reverse mode was set to 1.5, and 2.0, 5, and 1 teeth were found to be overinstrumented in respective settings. But there were large variations in overinstrumented distances when an attempt was made to compare the effect of irrigants on this overinstrumentations and they were meaningless for the small sample size. When all of the autoreverse setting were combined to compare the number of overinstrumented teeth with each irrigant, there were no significant differences (14 for normal saline, 12 for NaOCl, 13 for RC Prep
). When 0.5 or 1.0 automatic apical reverse setting mode was used the Tri Auto ZX
in clinical application, the possibility of overinstrumentation beyond the apical constriction exists in 55.9% of cases. Therefore 1.5 or 2.0 setting is safer for the preparation inside the canal but this type setting needs additional apical hand preparation of the root canal because the accuracy is lower than 0.5 or 1.0 setting.
TRANSLUCENCY OF LIGHT CURED COMPOSITE RESINS DEPENDS ON THICKNESS & ITS INFLUENCE ON COLOR OF RESTORATIONS
Hwang, In-Nam ; Lee, Kwang-Won ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 585~603
Esthetic availabilities used as an esthetic restorative maternals can be determined by the optical coincidence among materials, enamel and dentin. Enamel is highly translucent. That's why esthetic materials need to correspond the close translucency of enamel. But the translucent materials are affected by the background color. So it should be predicted that the color of estorative materials depend on the any thickness and the spectral reflectance of the background on which they are placed. The object of this investigation, under above hypothesis, was to determine and analyze how they affect the final color according to the thickness, translucency and background color (white, black and dentin) fill three commercial light cured composite resins(Charisma, Spectrum TPH and Z100). And correlation was analyzed to find out the possibility of the prediction when using the certain background color and thickness of materials. Followings are the result 1. The I shade of CHA showed the lowest contrast ratio(
) while the B3 shade of Z100 showed the highest contrast ratio(p<0.05). 2. The value of
on the white and dentin background is increased with decreasing thickness. And there are significant relationships between increasing thickness and each value(R>0.085). But there is a little change of
value on the black background regardless of the thickness(p>0.05). 3. For the
value, there was little difference in values as a function of thickness and changed irregularly regardless of thickness in all background. 4. The pattern of increasing value of
with decreasing thickness was similar to the group of white and dentin background. In both dentin one showed lesser change of value. 5. The values of
measured on the different background with same thickness showed the recognizable color difference(
>2) when the thickness was below 2.6mm. 6. Contrast ratio was increased with increasing thickness with significant relationship (R>0.9). 7. Spectral reflectance of composite resins that calculated from Kubelka-Munk equation was showed little difference compared with observed value w1th decreasing thickness.
EFFECT OF RESIN AND FILLER TYPE ON THE FRACTURE TOUGHNESS OF UTMA-BASED LIGHT-CURED COMPOSITES
Ahn, Yun-Sil ; Hwang, Su-Jin ; Bae, Tae-Sung ; Lee, Kwang-Won ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 604~613
This study was performed to evaluate the effect of resin and filler type on the fracture toughness of light-activated composites. Experimental composites were prepared using urethane tetramethacrylate(UTMA) and bisphenol glycidylmethacrylate(Bis-GMA) monomers and five different types of silica fillers. Fracture toughness was measured by a single edge V-notched beam(SEVNB) method, which was discussed from ASTM E399-78. Rectangular bars of
were prepared with experimental composites and a notch about 2.25mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed of 0.05mm/min and fracture surfaces were observed under scanning electron microscope. The results obtained were summarized as follows: 1. The fracture toughness values of UTMA-based composites were relatively higher than those of Bis-GMA-based composites. 2. The highest fracture toughness value was observed in the UTMA-based composite containing the
-spherical fillers. 3 Aging in the distilled water at
for 10 days showed the increase of fracture toughness, which was severer in the Bis-GMA-based composites than those of UTMA-based composites. 4. The AE amplitude occurring during the fracture toughness tests was the highest at the point of macroscopic fracture.
THE STUDY ON THE CHARACTERISTICS OF NOCICEPTIVE NEURONS IN TRIGEMINAL SUBNUCLEUS ORALIS
Ohn, Yeong-Suck ; Park, Soo-Joung ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 614~622
Recent studies have implicated that more rostral components of the trigeminal spinal nucleus including subnucleus oralis (Vo) in orofacial nociceptive mechanisms. Since there is only limited electrophysiological evidence, the present study was initiated to characterize the receptive field and response properties of malls nociceptive neurons in chloralose/urethan-anesthetized rats. Single neuronal activity was recorded in right subnucleus oralis, and types of nociceptive neurons classified wide dynamic range (WDR), NS (nociceptive specific) and deep nociceptive (D) and the mechanoreceptive field (RF) and response properties were determined. A total of 34 nociceptive neurons could be subdivided into 17WDR neurons, 12NS neurons and 5D neurons. Vo nociceptive neurons had RF involving maxillary and/or mandibular divisions mainly located in the intraoral and/or perioral regions. Majority of Vo nociceptive neurons showed spontaneous activity less than 1Hz. The NS and D neurons activated only by heavy pressure and/or pinch stimuli had high mechanical thresholds compared to WDR neurons activated also by tactile stimuli. Vo nociceptive neurons showed a progressive increase of response to the graded mechanical stimuli. 39% of Vo nociceptive neurons received C-fiber electrical input as well as A-fiber electrical input from their RF, and 45% of them responded to electrical stimulation of the right maxillary first molar. 41% of Vo nociceptive neurons responded to noxious heat applied to their RF, and 18% of them showed an immediate burst of discharges following MO application to the right maxillary first molar pulp. These results indicate that Vo is involved in the transmission of nociceptive information mainly coming from intraoral or perioral region including tooth pulp.
WORKING LENGTH CHANGE BY INSTRUMENTATION ACCORDING TO THE CANAL CURVATURE
Kim, Byung-Hyun ; Kim, Young-Sik ; Lee, Young-Kyoo ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 623~627
During canal instrumentation of a curved canal, restoring force of endodontic instrument remove more dentin from the inner wall of the curvature. This effect tends to straighten the canal and thus may significantly shorten the working length. This study was to determine the mean reduction in working length after instrumentation according to the curvature. The curvature of mandibular mesial root was determined before instrumentation. 30 canals were divided into 3 groups each 10 on the basis of degree of curvature. Experimental groups as follows. In group 1, canals having curvature from 15 to 20 degrees: in group 2, canals having curvature from 20 to 30degrees; in group 3, canals having curvature above 30 degrees. Experimental teeth in all groups were accessed, and their actual working length determined by passing a size 15 K-file(IAF) just through the minor apical foramen. The canals were sequentially enlarged to size 35 with ProFile .06 series. The change of working length was calculated by measuring the tip of IAF beyond apical foramen by using stereomicroscope. The change of canal curvature following instrumentation were measured using the Schneider technique. The results were as follows. 1. The greatest changes of curvature and working length were observed in the group 3 canals(P<0.05), next were group 2 canals and group 1 canals(P>0.05). 2. Group 1 canals showed a mean reduction in 1.61 degrees and length of 0.12m respectively(P>0.05). 3. Group 2 canals showed a mean reduction in 3.42 degrees(P<0.05) and length of 0.25mm(P>0.05) respectively. 4. Group 3 canals showed a mean reduction in 7.23 degrees(<0.05) and length of 0.64mm respectively(P<0.05).
A STUDY ON THE ACCURACY OF THE ROOT-ZX IN THE CANAL WITH MECHANICALLY FORMED CONSTRICTION
Kim, Byung-Hyun ; Lee, Young-Kyoo ; Kim, Young-Sik ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 628~632
Currently electronic apex locators have been widely used to determine working length in endodontic treatment. According to Manufacture's recommendation, it is beneficial to find the working length before instrumenting the canal. However, in crown-down pressureless technique, working length of tooth is established following coronal instrumentation 3mm short of radiographic apex. In narrow canals, mechanically formed constriction might be established by coronal instrumentation in some distance from anatomical constriction. The purpose of this study was to evaluate the accuracy of Root-ZX in the canal with mechanical constriction following considerable coronal enlargement with ProFile .06 series. The 40 root canals in 30 extracted mandibular molars were accessed, and their actual length (AL) established by passing a size 10 file just through the minor apical foramen. The teeth were then embedded in an acrylic container with normal saline. The initial canal length(IL) was measured with Root-ZX by negotiating a size 10 file to the apical constriction. The canal was sequentially enlarged to size 40 with ProFile .06 file 3mm short of actual length. The enlarged final canal lengths (FL) were obtained with a size 15 file. The average values of IL, FL were calculated and compared using Repeated measures Analysis of Variance followed Turkey's Studentized Range test. The results were obtained as follows: 1. The initial canal length was 0.12mm shorter than actual canal length(P>0.05). 2. The differences between initial canal length and final canal length were not significant(P>0.05). 3. As a result of this study, regardless of mechanically formed constriction. Root-ZX differentiated between mechanical and anatomic constriction.
A STUDY ON THE SHAPE OF A CANAL PREPARED WITH PROFILES IN A CURVED CANAL
Park, Han-Soo ; Lee, Min-Koo ; Kim, Jong-Jin ; Lee, Jong-Yeop ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 633~638
The purpose of our study is to evaluate the ability of nickel-titanium(NiTi) files in maintaining the original curvature of a curved root canal during canal preparation. Curved canals on translucent resin blocks were prepared with Profiles and stainless steel files and they were placed at the platform which can reproduce the same position. The unprepared and prepared canal forms were accurately compared by double exposure technique of photography. The results were as follows : 1 NiTi files made a canal comparatively taper, but stainless steel files didn't make a canal taper, wicest at midportion and comparatively wide at a apical portion. 2. Canals preparations with no. 25 Profile.06 up to the working length were most excellent in taperness and in maintaining the original curvature. Canals prepared with no 30 Profile.06 up to the working length made a little outer transportation at a apical portion, but not severe. 3. Canal preparations with Profile GT were excellent in taperness and in maintaining the original curvature, but made more enlargement toward the inner side at the starting portion of the curvature. 4. Canal preparations with stainless steel files were not tapered and provided the largest transportation.
SOME CONSIDERATIONS ON ESTABLISHING DENTAL CARE DELIVERY SYSTEM AND DENTAL SPECIALTY SYSTEM IN KOREA
Han, Young-Chul ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 639~646
The dental care delivery system and the dental specialty system have a very close relationship each other. Compared to Korea. Western European countries with predominant public sector in dental service have recognized merely 2 or 3 dental specialties, while North American countries with predominant private sector, 8 or 9 ones. It is desirable to adopt the dental specialty system as soon as possible in Korea to encourage scientific development in various dental specialties and qualitative advance in dental service. We, however, have to establish equitable dental care delivery system which can use limited dental resources efficiently as follows. 1. clarifying the different roles in assignments between general dentists and specialists by the amendment of the related laws such as the Medical Act and establishing the organic patient-referral system. 2. adopting the dental specialty system and expanding personnel and equipments so that the dental college hospitals, especially dental divisions of general hospitals, night function as secondary care facilities with specialties. 3. determining the size of dental specialists according to the national needs for dental specialized service's, whose number is to be not more than 10% of the total dentists. 4. transferring the function of accredating dental specialists to the efficient, self-controlled professional organization such as the Korean Dental Association rather than putting it under the governmental control. 5. conducting a comprehensive review of specialty education and practice for re-recognition, and maintaining competence of specialists by re-accredating them periodically. I expect this article to contribute to further discussion about the dental specialty system in Korea in productive and practical way. I am sure that we can Establish this system in the near future when people in every walks of life-the academic circle, the press, the authority concerned, consumer groups and the Korean Dental Association-take part in the discussion with special concern.
SHEAR BOND STRENGTH AND MICROLEAKAGE OF COMPOSITE RESIN ACCORDING TO TREATMENT METHODS OF CONTAMINATED SURFACE AFTER APPLYING A BONDING AGENT
Park, Joo-Sik ; Lee, Suck-Jong ; Moon, Joo-Hoon ; Cho, Young-Gon ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 647~656
The purpose of this study was to investigate the shear bond strength and marginal microleakage of composite to enamel and dentin according to different treatment methods when the applied bonding agent was contaminated by artificial saliva. For the shear bond strength test, the buccal and occlusal surfaces of one hundred twenty molar teeth were ground to expose enamel(n=60) and dentin surfaces(n=60). The specimens were randomly assigned into control and 5 experimental groups with 10 samples in each group. In control group, a bonding system(Scotchbond
Multi-Purpose plus) and a composite resin(Z-100
) was bonded on the specimens according to manufacture's directions. Experimental groups were subdivided into 5 groups. After polymerization of an adhesive, they were contaminated with at artificial saliva on enamel and dentin surfaces: Experimental group 1 ; artificial saliva was dried with compressed air. Experimental group 2 ; artificial saliva was rinsed with air-water spray and dried. Experimental group 3 ; artificial saliva was rinsed, dried and applied an adhesive. Experimental group 4 ; artificial saliva was rinsed, dried, and then etched using phosphoric acid followed by an adhesive. Experimental group 5, artificial saliva was rinsed, dried, and then etched with phosphoric acid followed by consecutive application of both a primer and an adhesive. Composite resin(Z-100
) was bonded on saliva-treated enamel and dentin surfaces. The shear bond strengths were measured by universal testing machine(AGS-1000 4D, Shimaduzu Co. Japan) with a crosshead speed of 5mm/minute under 50kg load cell. Failure modes of fracture sites were examined under stereomicroscope. The data were analyzed by one-way ANOVA and Tukey's test. For the marginal microleakage test, Class V cavities were prepared on the buccal surfaces of sixty molars. The specimens were divided into control and experimental groups. Cavities in experimental group were contaminated with artificial saliva and those surfaces in each experimental groups received the same treatments as for the shear test. Cavities were filled with Z-100. Specimens were immersed in 0.5% basic fuchsin dye for 24 hours and embedded in transparent acrylic resin and sectioned buccolingually with diamond wheel saw. Four sections were obtained from the one specimen. Marginal microleakages of enamel and dentin were scored under streomicroscope and averaged from four sections. The data were analyzed by Kruskal-Wallis test and Fisher's LSD. The results of this study were as follows. 1. The shear bond strength to enamel showed lower value in experimental group 1(13.20
2.94MPa) and experimental group 2(13.20
2.94MPa) than in control(20.03
4.47MPa), experimental group 4(20.96
4.25MPa) and experimental group 5(21.25
4.48MPa) (p<0.05). 2. The shear bond strength to dentin showed lower value in experimental group 1(9.35
4.11MPa) and experimental group 2(9.83
4.11MPa) than in control group(17.86
4.03MPa), experimental group 4(15.04
3.22MPa) and experimental group 5(14.33
3.00MPa) (p<0.05). 3. Both on enamel and dentin surfaces, experimental group 1 and 2 showed many adhesive failures, but control and experimental group 3, 4 and 5 showed mixed and cohesive failures. 4. Enamel marginal microleakage was the highest in experimental group 1 and there was a significant difference in comparison with other groups (p<0.05). 5. Dentin marginal microleakages of experimental group 1 and 2 were higher than those of other groups (p<0.05). This result suggests that treatment methods, re-etching with 35% phosphoric acid followed by re-application of adhesive or repeating all adhesive procedures, will produce good effect on both shear bond strength and microleakage of composite to enamel and dentin if the polymerized bonding agent was contaminated by saliva.
CHANGES IN AUTONOMIC RESPONSES AND JAW MUSCLE ACTIVITY INDUCED BY TOOTH PULP STIMULATION IN THE RAT
Yu, Mi-Kyung ; Park, Soo-Joung ;
Restorative Dentistry and Endodontics, volume 24, issue 4, 1999, Pages 657~665
The effects of application of mustard oil (MO), a small-fiber excitant and inflammatory irritant into the rat maxillary molar tooth pulp on arterial blood pressure and heat race, and electromyographic (EMG) activity of the jaw muscles were assessed in the anesthetized rats. In addition, Evans blue extravasation following pulpal MO application was measured. Application of MO into the tooth pulp produced a significant increase in mean arterial pressure and heat rate which gradually returned to baseline level. Application of MO into the tooth pulp induced a significant and short-lasting increase in EMG activity of digastric masseter and tongue muscle. Application of MO into the tooth pulp significantly increased the plasma extravasation of Evans blue dye. However, Application of mineral oil into the tooth pulp did not produce any significant changes in EMG activity of the digastric, masseter and tongue muscles, mean arterial pressure and heart rate, and plasma extravasation of Evans blue dye. These findings indicate that changes in arterial blood pressure, heart rate, jaw muscle activity and plasma extravasation accompanying noxious tooth pulp stimulation call be utilized as indirect measure of orofacial pain and inflammation.