• Journal of Periodontal and Implant Science
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• v.27 no.1
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• pp.205-215
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• 1997

In periodontal regeneration treatment, access to the frucation area is very difficult. Thus complete removal of plaque, calculus and endotoxin is somewhat impossible. In this study, teeth that were extracted due to periodontal disease were used. The furcation area was treated with periodontal curette, ultrasonic scaler, roto bur and they observed using SEM. The result was follows 1. The group treatment with curette showed remaining plaque, the cementum existed in most of the surface and partial dentinal tubule orifice could be seen. 2. The group treatment with ultrasonic scaler showed less removalof plaque compared to curette and irregular surface could be seen. 3. The group treatment with roto bur showed cleaner surface and many dentinal tubule orifice could be seen compared to the curette and ultrasonic scaler groups. Thus when suing treatments such as bone grafting or guided tissue regeneration, it is considered that the furcation area should be treatment with Roto bur.

• Journal of Periodontal and Implant Science
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• v.29 no.4
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• pp.861-872
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• 1999

Since pathologic changes of exposed root surface inhibit cell attachment and new attachment of connective tissue have been made, many efforts were apply to change the exposed root surface condition. Scaling and root planing can not remove the endotoxin completely and forms the smear layer which prohibits the new attachment of connective tissue. Therefore, many kinds of chemicals were used for controlling the pathologic change of the root surface. The purposes of this study was to compare and observe the changes of the exposed root surface treated by scaling and root planning, Tetracycline HCl and Argon Laser. After the scaling and root planning of ten extracted premolars, the differences & the root surface among groups were observed under SEM. Control group showed smear layer and irregular amorphous surface. The dentinal tubule was not exposed. The debris and scale like texture were also observed. Tetracycline HCl treated group showed relatively smooth surface and the collagen fiber was observed in the dentinal tubule. Argon Laser treated group showed the most effective results under the conditions of 0.8 to 1.0w irradiation for 0.5 to 1.0 sec with pulse wave. The results of this study showed that the root surface change was associated with the intensity and the duration of Argon Laser irradiation. Further investigation for the surface change with the Argon Laser irradiation is recommended for understanding of clinical effect.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.401-412
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• 1998

The aim of this study was to measure the regional micro-shear bond strength of dentin bonding agents to dentin, and to investigate the relationship between the micro-shear bond strength and two dentinal characteristics ; Vickers hardness and remaining dentin thickness. Twenty-four freshly extracted, noncarious human molars were selected for this study. The materials tested in this study consisted of two commercially available dentin bonding agents (MAC-BOND, ONE-STEP) and two restorative light-cured composite resins (AELITEFIL, Z100). The occlusal or side surface of tooth crown was sectioned to expose dentin, and the exposed surface was finally polished with # 600 sandpaper. Four groups of application methods were used combining the filling materials and the dentin bonding agents. The composite resin-attached tooth specimens were embeded in a cold cure acrylic resin, and were cut with a low speed diamond saw to the dimension of 1mm $\times$ 1mm. Nine specimens were obtained from each tooth. The cut specimens were divided into three groups depending on the position of the dentin bonding surface. The micro-shear bond strength, remaining dentin thickness, and dentinal hardness were measured. Experimental results were then statistically analyzed with ANOVA. t-test, Scheffe test, and regression analysis. From this experiment, the following results were obtained : 1. In the case of occlusal surface bonding, the pooled micro-shear bond strength of ONST-AELIT group (16.62 MPa) was significantly higher than that of MACB-AELIT group (9.91 MPa) (p<0.05). However, there was no significant difference in the micro-shear bond strength depending on the dentin position (p>0.05). 2. In the case of side surface bonding of crown, the pooled micro-shear bond strength of four different bonding groups was not significantly different among each other (p>0.05). However, in three of the test groups (ONST-AELIT, MACB-Z100, ONST-Z100), the micro-shear bond strength to the lower 1/3(III) position was significantly lower than that to middle 1/3(II) position of surface (p<0.05). 3. In the ONST-AELIT bonding group, the pooled micro-shear bond strength to the occlusal surface was significantly lower than that to the side surface of crown (p<0.05). 4. There was no significant correlation between the micro-shear bond strength and dentin hardness / remaining dentin thickness (p>0.05).

• Journal of Oral Medicine and Pain
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• v.12 no.1
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• pp.27-40
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• 1987

When the men die, uniform changes progress. Many investigators have studied about the time after death, but it's very difficult to measure the time elapsed since death, particularly in highly decomposed or probably skeletonized bodies. But the teeth are very stable to the changes of physical and chemical properties and their changes are very slow. At this point of view, the author studied this theme as one of the pioneers in our country. In this study, the author observed the degree of the dentinal expansion and the crack of enamel and cementum of the teeth which had been extracted from December, 1983 to September, 1987. The teeth were extracted from the male and female who was 18 to 85 year old. The results are followed; 1. The degree of dentinal expansion increased rapidly until 7 months with high degree and then decreased slowly. 2. The equation of regression for representing x as the degree of the dentinal expansion and y as the time elapsed since death, is y = 29.43-1.13x (p<0.05) 3. The crack of the enamel surface seemed to begin at 1 year from extraction and to increase apparently before or after 20 months. 4. The crack of the cementum began at 3 months from extraction and dendrite crack began at 16 months from extraction. After this, the crack increase continuously and the rate of cracking were more rapid as compared with that of enamel. 5. It seems to be useful to measure the time elapsed since death using the degree of dentinal expansion and the crack of enamel and cementum, particularly in the old bodies after death.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.719-730
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• 2005

The purpose of this study was to compare the effect of tetracycline HCL, Citric acid and PrefGel applied on the root surfaces that planed with periodontal curret with Roto bur. In this study, 20 extracted teeth with advanced periodontal disease were used. The teeth were root planing with periodontal curette and Roto bur. Following root planing, each agents was burnished on the prepared root surface for 3 minutes to find opened dentinal tubules. And then, each specimens were investigated using scanning electron microscope. Amount of remained cementum by loss of tooth substance index and the number of opened dentinal tubules were evaluated to each specimens The results were as follows. 1. Groups treated with periodontal curette were almost seemed no removed. Other groups treated with Roto bur showed partially opened dentinal tubule orifices. 2. Loss of tooth substance index were compared between groups. There was no statistically difference between periodontal curette groups. Between Roto bur groups was alike. But there were statistically differences between periodontal curette and Roto bur groups. 3. At comparing with various root conditioning agents, Tetracycline HCL group took statistically higher than Citric acid and PrefGel in opened dentinal tubules. On the other hand, there was no statistically difference between Citric acid group and PrefGel group. As a result of this study, groups treated with Roto bur showed more cementum removed than groups treated with periodontal curette. In a treatment for regeneration of periodontal tissue, it was regarded that Roto bur should be used and that Tetracycline HCL would be more effective as chemical root conditioning agent.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.1
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• pp.26-49
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• 1998

The purpose of this study was to confirm the formation of hybrid layer and resin tags in dentin tissue and the possibility of bonding between luting cements used for the prosthesis and the resinous surface coated with resin bonding agents to prevent the dentin hypersensitivity after abutment preparation. Some resin bonding agents, which may have the possibility of bonding with polyacrylic acid as a liquid ingredient of polycarboxylate and glass ionomer cements, were selected. All-Blond desensitizer containing NTG-GMA and BPDM, Scotch-Bond Multipurpose plus containing HEMA, and XR-bond containing organophosphate were selected as a coating agent. Dental cements were zinc phosphate, polycarboxylate, and glass ionomer cement. After the exposed dentin surface of premolars was ethced with 10% phosphoric acid and coated with resin bonding agents, the morphology of treated surfaces and the resin tags and hybrid layers on sectioned surfaces were observed by SEM. Shear bond strength between the resin bonding agents and 3 kinds of cements was measured 24 hours after bonding. On the debonded surfaces of the shear bond strength tested specimens, the cement tags and the bonding sites between the resin materials and cements were examined by SEM. Following conclusions were drawn : 1. Coating of dentin with resin bonding agents had no effect on the shear bond strength of zinc phosphate cement. 2. Both of polycarboxylate and glass ionomer cements showed the increased shear bond strength by the dentinal coating with Scotch-Bond Multipurpose plus containing HEMA. However, in the case of dentinal coating with some agents containing NTG-GMA and BPDM or organophosphate, polycarboxylate cement exhibited the lowered shear bond strength, and glass ionomer cement showed the unchanged shear bond strength. 3. Complete obstructions of dentinal tubules were observed on the dentin coated with All-Bond desensitizer or XR-bond, but distinct shape of the orifices of dentinal tubules was observed consistently on the dentin coated with Scotch-Bond Multipurpose plus. 4. The hybrid layer was thickest on the dentin coated with All-Bond desensitizer, and the length of resin tags was longest on the dentin coated with Scotch-Bond Multipurpose plus. 3. On the debonded specimens which had been bonded with polycarboxylate cement or glass ionomer cement after coating with Scotch-Bond Multipurpose plus, the cement tags and the bonding sites between the resinous surface and the cements could be examined.

• Proceedings of the KACD Conference
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• 2003.11a
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• pp.568-568
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• 2003

I. Objectives This study investigated the effect of rewetting agent on dentinal microtensile bond strengths(${\mu}TBS$), using one bottle adhesives. II. Materials and Methods Non caries human molars were sectioned to exposed the superficial dentin surfaces, etched 15 seconds using 32% phosphoric acid and 10 seconds rinsed. Samples were randomly divided into two groups according to adhesives (Single Bond, One-Step) used. Each group were subdivided into five groups by different dentin surface treatment：15 second dry(D), blot dry(BD) or 15 second dry and rewetted with distrilled water(DW), Gluma Desensitizer(GD) and Aqua-Prep(AP) during 30 second, respectively.(omitted)

• Restorative Dentistry and Endodontics
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• v.14 no.2
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• pp.103-110
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• 1989

The purpose of this study was to evaluate the cleansing effect of Glyoxide on the dentinal walls of the root canal. Fourty teeth were divided into four groups and the canals in each group were individually enlarged with K-file by step-back technic and irrigated with one of four irrigants. The four used irrigants were Glyoxide (Marion lab. U.S.A.) in combination with 3.5% sodium hypochlorite, 3.5% sodium hypochlorite, 3.5% sodium hypochlorite in combination with 3% hydrogen peroxide and normal saline solution. All the irrigants were used in conjunction with instrumentation as they would be during clinical conditions. After final irrigation, the canals were dried with paper points and the teeth were split longitudinally. The cleaness of canal walls according to the size and the level of canals were evaluated under steroscope by t analysed statistically The results were as follows. 1. The use of 3.5% sodium hyphochlorite in combination with 3.0% hydrogen peroxide revealed the most clean canal surface regardless of the size of canal at apical third of root canal (p < 0.05). 2. Glyoxide in combination with 3.5% sodium hyphchlorite showed no significant difference in cleaning effect of canal surface compared with 3.5% sodium hypochlorite and normal saline solution at the apical third of narrow canal. 3. Glyoxide in combination with 3.5% sodium hypochlorite revealed no significant difference in debridement of canal walls compared with 3.5% sodium hypochlorite in combination with 3% hydrogen peroxide and saline solution at the middle third of narrow and large canals.

• Restorative Dentistry and Endodontics
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• v.33 no.2
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• pp.141-147
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• 2008

This study was aimed to develop an instrument for real-time measurement of fluid conductance and to investigate the hydrodynamics of dentinal fluid. The instrument consisted of three parts; (1) a glass capillary and a photo sensor for detection of fluid movement, (2) a servo-motor, a lead screw and a ball nut for tracking of fluid movement, (3) a rotary encoder and software for data processing. To observe the blocking effect of dentinal fluid movement, oxalate gel and self-etch adhesive agent were used. BisBlock (Bisco) and Clearfil SE Bond (Kuraray) were applied to the occlusal dentin surface of extracted human teeth. Using this new device, the fluid movement was measured and compared between before and after each agent was applied. The instrument was able to measure dentinal fluid movement with a high resolution (0.196 nL) and the flow occurred with a rate of 0.84 to 15.2 nL/s before treatment. After BisBlock or Clearfil SE Bond was used, the fluid movement was decreased by 39.8 to 89.6%.

• Restorative Dentistry and Endodontics
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• v.21 no.1
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• pp.70-86
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• 1996

The purpose of this study was to analyze the stress distribution in mandibular second premolars restored with different post and core techniques. Sixteen two-dimensional finite element model of mandibular second premolars restored with post and core and complete crown were developed according to the diameter, length, and material of post and core. Vertical force, 10N in magnitude, was applied first to the central fossa and then $45^{\circ}$ oblique force of same magnitude was applied to the buccal contact surface of buccal cusp. The obtained results were as follows : 1. Stress distribution within the dentin 1) Regardless of the material of the post and core and the diameter and length of the post, the pattern of stress distribution within the dentin was similar. 2) Maximum dentinal stress was observed on the lingual root surface of alveolar crest level with oblique loading and on lingual side of root dentin at the crown margin on vertical loading. 3) Cast post and cores produced the lowest dentinal stress concentrations and the highest stress concentration was observed in composite resin post and cores. 2. Stress distribution within the post and core 1) Within the amalgam and composite resin post and core, the patterns and maximum values of stress were similar. Maximum stress located at the central fossa of core portion on vertical loading and at the lingual junction of post and core with oblique loading. 2) Among the all post and cores, the cast post and core registered the highest stress concentration and maximum stress value within the post. Maximum stress located at the post apex on vertical loading and at lingual half of the post surface with oblique loading. 3) In case of Para-post and amalgam core, maximum stress located at the central fossa of core portion and lingual tip of the post head on vertical loading. With oblique loading, maximum stress located at the lingual half of the post surface.