• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.243-250
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• 2010

Purpose: This study evaluated the effect of different screw tightening sequences and methods on detorque values in a well-fitting implant superstructure. Materials and methods: A fully edentulous mandibular master model and a metal framework directly connected to four parallel implants (Astra Tech) with a passive fit to each other were fabricated. Six stone casts were made with a splinted impression technique to represent a 'well-fitting' situation with the metal framework. Detorque values were measured twice after screw tightening using 20 Ncm. Detorque values and minimum detorque values for three screw tightening sequences (1-2-3-4, 2-4-3-1, and 2-3-1-4) and for two tightening methods (two-step and one-step) were analyzed using multi-way analysis of variance and two-way analysis of variance, respectively, at a .05 level of significance. Results: The mean detorque values for screw tightening sequences ranged from 12.8 Ncm (2-4-3-1) to 13.1 Ncm (2-3-1-4), and for screw tightening methods were 13.1 Ncm (two-step) and 11.8 Ncm (one-step). The mean of mimimum detorque values for screw tightening sequences were 11.1 Ncm (1-2-3-4) and 11.2 Ncm (2-4-3-1 and 2-3-1-4), and for screw tightening methods were 11.2 Ncm (two-step) and 9.9 Ncm (one-step). No statistically significant differences among three screw tightening sequences were found for detorque values and for mimimum detorque values. But, statistically significant differences between two screw tightening methods were found for two values. Two-step screw tightening method showed higher detorque value (P = .0003) and higher minimum detorque value (P = .0035) than one-step method. Conclusion: Within the limitations of this study, the screw tightening sequence was not a critical factor for the detorque values in a well-fitting implant superstructure by the splinted impression technique. But, two-step screw tightening method showed greater detorque values than one-step method.

• Korean Journal of Food Science and Technology
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• v.33 no.6
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• pp.753-759
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• 2001

To evaluate antiinflammation of Aloe vera peel, antiimflammation substances were extracted from Aloe vera peel and identified, and we investigated the effect of the its substance the inhibitory effect on the activity of hyaluoronidase, elastase, collagenase and prostaglandin endoperoxide synthase. The water extract from Aloe vera peel were successfully purified with solvent fractionation, silica gel column chromatography, preparative thin layer chromatography and UV spectrometer. Two purified active substances were identified as aloe-emodin and barbaloin by Mass Spectrometer, $^1H-NMR$ and FT-IR. Aloe-emodin and barbaloin. $IC_{50}$ values of aloe-emodin and barbaloin against hyaluronidase activity were 40 and $70\;{\mu}g/mL$, respectively. Leuckocyte elastase, which is related to the destruction of various tissue, $IC_{50}$ values of them were 50 and $60\;{\mu}g/mL$, respectively. $IC_{50}$ values of aloe-emodin and barbaloin against collagenase activity were 40 and $60\;{\mu}g/mL$, respectively. and $IC_{50}$ values of aloe-emodin and barbaloin aganist the prostaglandin endoperoxide synthase, which play an important role in inflammatory reactions, were 40 and $70\;{\mu}g/mL$, respectively. Inhibitory effects of aloe-emodin, barbaloin and aspirin against carrageenan paw edema were 74.9, 52.9 and 51.9% as inhibiton percentage, respectively, at dose of 100 mg/kg and that of indomethancin was 49.7 at dose of 10 mg/kg. Cell cytotoxicity of barbaloin against human gingival cells was lower than that of aloe-emodin. Aloe-emodin and barbaloin did not show cytotoxicity against human gingival cells at concentration of 1.0 and $5.0\;{\mu}g/mL$, However, aloe-emodin and barbaloin showed less cytotoxicity than chlorhexidine, which usually have been used as the agent of anticaries and antiinflammation. These results suggested that aloe-emodin and barbaloin from Aloe vera peel have the effect of anticaries and antiinflammation.

• The Journal of Korean Academy of Prosthodontics
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• v.49 no.4
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• pp.308-315
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• 2011

Purpose: The purpose of this study was to colorimetrically evaluate the masking effect of different opacity of ingots on the final shade of IPS Empress Esthetic$^{(R)}$ laminate veneer restorations using the CIE $L^*a^*b^*$ system. Materials and methods: Six porcelain disks of IPS Empress Esthetic$^{(R)}$ system (translucency: E 01, E 03, E 0C-1, E TC-1, E TC-2, E TC-3) were fabricated with 7 mm in diameter and 0.6 mm in thickness. Six extracted human incisors (shade: A1, A3, A4, B2, B3, C3) were used as the abutment specimens. The incisors were prepared using a diamond wheel and made with a flat labial surface on the middle 1/3. For each combination of different shades of abutments and copings, the change in color was measured with a colorimeter. CIE $L^*a^*b^*$ coordinates were recorded for each specimen. Color differences (${\Delta}E$) were calculated. Descriptive statistical analysis was done. Results: ${\Delta}E$ values were significantly affected by coping translucency and abutment shade (P<.05). The color differences (${\Delta}E$) of laminate veneers among abutments with A3, B3, C3, and A4 shade were mostly below 2.7 which was within the clinically acceptable range, while color differences between A4 and B2, A3 and B2, and A1 and A4 showed more than 2.7. Conclusion: The final color of IPS Empress Esthetic$^{(R)}$ laminate veneers were significantly influenced by translucency of the coping and shade of abutment teeth. The large value difference of abutment teeth limited the masking ability by laminate veneers.