• Archives of Plastic Surgery
• /
• v.38 no.6
• /
• pp.747-754
• /
• 2011

Purpose: The Abbe flap procedure has been used to correct disharmony of the upper and lower lips as well as for making a philtrum for patients with secondary cleft lip deformities. But the Abbe flap procedure adds two scars in addition to the prior operative scar on the upper lip. This study was conducted to determine the treatment outcomes of esthetic subunit excision of the scar on the philtrum and Abbe flap coverage for correction of cleft lip deformities with photogrammetric analysis. Methods: This study investigated a total of 11 patients with cleft lip deformities who underwent scar excision with Abbe flap coverage, and the patients were followed up for at least 6 months. Under general anesthesia, a mushroom-shaped Abbe flap was drawn on the lower lip with a width of 8 mm and a height 1~2 mm longer than that of the philtral midline. The epidermis and dermis of the scar on the upper lip were excised. In the cases with alar base depression, the orbicularis oris muscle was split vertically and transposed to the alar base. The Abbe flap was harvested as a pedicled flap containing a small amount of muscle and this was rotated 180-degree to be inserted into the upper lip. Mucosa, muscle, subcutaneous tissue and skin were closed in layers. The flap was divided at the 7~14 postoperative day. The postoperative outcomes were evaluated by using photogrammetric analysis. Three indices were measured from the standard clinical photographs taken before and after the surgery. For anthroposcopic assessment, observers described the postoperative outcomes using an ordinary scale method. Results: The postoperative values obtained in the photogrammetric analysis showed improvement as compared with the preoperative ones. Improved anthroposcopic outcomes were also noted. Conclusion: Scar excision and Abbe flap coverage were proven to be effective in improving protrusion and the height of the upper lip, the scar of the upper lip and the symmetry of Cupid's bow and the philtral column, as well as formation of the philtral dimple.

• Journal of Technologic Dentistry
• /
• v.33 no.3
• /
• pp.203-210
• /
• 2011

Purpose: The purpose of this study was to compare color correspondence of different sizes of Vita Mark II$^{(R)}$ and TriLuxe$^{(R)}$ Feldspar blocks. Methods: The three commercially available shades(1M2, 2M2, 3M2) of Mark II & TriLuxe blocks for the CEREC$^{(R)}$ CAD/CAM system were examined. For each of three colors, three different sizes were tested, 5 blocks each. The measurements were made using a spectrophotometer equipped with an integrating sphere using the CIE $L^*$, $a^*$, $b^*$ colorimetric system. Results: The $L^*$, $a^*$, $b^*$ value of Vita Mark II$^{(R)}$ ceramic block showed significantly higher than TriLuxe$^{(R)}$ ceramic block(p<0.05). In comparing the Vita Mark II$^{(R)}$ specimen of the three different shade, color differences between materials(${\Delta}E^*$) showed the lowest value of 2.09, and the highest was 2.24. ${\Delta}E^*$ values of the materials of Vita Mark II$^{(R)}$ were higher than 2. As the size of ceramic block differed, the color correspondence of Vita Mark II$^{(R)}$ showed statistically significant difference but, this result is clinically acceptable. Conclusion: All the different sizes of the different shades of Vita TriLuxe$^{(R)}$ blocks for the CEREC$^{(R)}$ system showed the high degree of color correspondence necessary in industrially prefabricated CAD/CAM blocks. The results of the present study suggested that it would be necessary to establish the reproducible and constant color specification system for an esthetic restoration.

• Journal of Korean Society of Steel Construction
• /
• v.18 no.6
• /
• pp.747-758
• /
• 2006

With the growth of economy, the esthetic values of bridges become significant points in the decision process of a type of new bridges. So, it is common that a long-span bridge or a multi-purpose bridge are selected as the type of new bridges. Also, the economic growth derives increase in traffic and then the increased traffic derives multi purpose bridges from the decision process of bridge types. In the multi-purpose bridges with private fund, the construction cost is simply alloted to several organizations according to the percentage of participation and usage. But the allotment of the maintenance cost is not simple. Because the loads and safety factors in design are different between the criterion of design of highway bridges and that of railway bridges. In this study, we verify the possible problems in case of allotment method of maintenance cost in foreign examples as well as domestic example. As one of the method of determination of allotment ratio in maintenance cost, the method based on the stress of structural analysis is presented and it can be an example in the similar problem later.

• The Journal of Korean Academy of Prosthodontics
• /
• v.45 no.1
• /
• pp.21-33
• /
• 2007

Statement of problem: The esthetic component of dental care has become increasingly more important, while new tooth-colored materials are continually marketed. Various new indirect composite materials have been developed with required advantages. The most recent development in the indirect composites has been the introduction of the second-generation laboratory composite or poly-glass materials. They are processed by different laboratory techniques based on combinations of heat, pressure, vacuum and light polymerization. Although, second generation products became available in 1995, their characteristics and clinical performance have not been adequately investigated. Purpose: The aim of this study was to measure the mechanical properties of the second generation indirect resin system and compare these with an existing universal direct composite resin. Material and method: In this study four indirect composite material (Adoro LC, BelleGlass HP, Tescera, Synfony) were tested for flexural strength, wear resistance, hardness and their degree of conversion against Z250, a light cure direct composite. Results: Within the limitations of this study, the following conclusions were drawn: 1. From the abrasion wear result, Adoro showed the least volume loss while Synfony showed the greatest volume loss. Z250 and BelleGlass HP didn't show significant difference (p>0.05), but they showed significant difference with other groups (p<0.05). From the attrition wear, BelleGlass HP showed the least volume loss and it didn’t show significant difference with Tescera (p>0.05). While Synfony showed the greatest volume loss that it showed significant difference with other groups (p>0.05). 2. Mean values of flexural strength by means of three point bending test was in the order of Z250, Adoro, Belleglass HP, Tescera and Synfony. Mean elastic modulus was in the order of Z250, BelleGlass HP, Tescera, Adoro and Synfony. 3. The result of Vicker‘s microhardness value showed that significantly higher value in Z250 (p<0.05), and is in the order of BelleGlass HP, Tescera, Adoro and Synfony. 4. The degree of conversion measured by FT-IR showed significantly higher value in BelleGlass HP (p<0.05), and is in the order of Adoro, Synfony, Tescera and Z250. Conclusion: Significant differences were found in the flexural strength, wear resistance, hardness and their degree of conversion.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.25 no.4
• /
• pp.349-360
• /
• 2009

Purpose: As the esthetic demands of dental implant patients are increased, the demands of zirconia as implant abutment material are also increased. It has non-metalic color, good biocompatibility, high strength and high toughness. Even thought the advatage of zirconia abutment, there are a few studies about mechanical properties of zirconia abutment. This study evaluated the mecanical strength with compressive bending strength and endurance limit of implant-zirconia abutment assembly. Materials and Methods: Static and cyclic loading of implant-Zirconia abutment assembly were simulated under worst case condition according to ISO. Test groups were implants of external butt joint with straight regular diameter and angled regular diameter zirconia abutment, implant of external butt joint with narrow straight diameter zirconia abutment and implant of internal conical joint with straight narrow diameter zirconia abutment. All test group were evaluated the mecanical strength with compressive bending strength and endurance limit. After fatique testing, fracture surface were examined by SEM. Results: The compressive bending strengths exceed 927N. Regular diameter zirconia abutment were stronger than narrow diameter zirconia abutment(P<.05). The endurance limits ranged from 503N to 868N. Conclusion: Within the limitation of this study, zirconia implant abutment exceeded the estabilished values for maximum incisal biting forces reported in the literature.

• The Journal of Korean Academy of Prosthodontics
• /
• v.37 no.4
• /
• pp.454-464
• /
• 1999

The metal ceramic crown is currently the most popular complete veneer restoration in dentistry, but in many cases, the metal cervical collar at the facial margin is unesthetic and unacceptable. Facial porcelain margin has been used in place of it. But this dose not solve the problems, such as dark gingival discoloration and cervical opaque reflection of porcelain veneer. Recently, metal copings which were designed to terminate its labio-cervical end on the axial walls coronal to the shoulder have been clinically used to solve the esthetic problem of metal ceramic crown. But in this design, porcelain veneer of labio-cervical area which is not supported by metal may not be able to resist the stress during cementation and mastication. The purpose of this study was to evaluate fracture strength and fractured appearance of crowns according to different coping designs. A resin maxillary left central incisor analogue was prepared for a metal ceramic crown, and metal dies were made with duplication mold. Metal copings were made and assigned to one of four groups based on facial framework designs: group 1, coping with 0.5mm metal collar; group 2, metal extended to the shoulder; group 3, metal extended to 1mm coronal tn the shoulder: group 4, metal extended to 2mm coronal to the shoulder. Copings and crowns were adjusted to be same size and thickness, and cemented to metal dies with zinc phosphate cement by finger pressure. Fracture strength was measured with Instron Universal Testing Machine. Metal dies were anchored in Three-way-vice at 3mm below finish line and at $130^{\circ}$ inclined to the long axis of the crown. Load was directed lingually at 2mm below midincisal edge. Load value at initial crack and at catastrophic fracture was recorded. The results obtained were as follows : 1. Fracture strength values at initial crack were higher in groups 1, 2 than in groups 3, 4 but this difference was not statistically significant(P<0.05). 2. Conventional metal collared crown had greater catastrophic fracture strength than any other collarless crowns. 3. The greater the labial metal coping reduction, the lower the catastrophic fracture strength of crowns but when more than 1mm of labial metal reduction was done, the difference in strengths was not statistically significant(p<0.05). 4. The strongest collarless coping design was group 2.

• Journal of the korean academy of Pediatric Dentistry
• /
• v.29 no.1
• /
• pp.19-29
• /
• 2002

The purpose of this study was to compare the polymerization shrinkage and the compressive strength of composite and compomer cured with two different light sources ; conventional halogen-light curing unit and recently-developed plasma arc curing unit. The 'strain gauge method' was used for determination of polymerization shrinkage and the compressive strength was measured by universal testing machine. The results of the present study can be summarized as follows: 1. Filling materials in polyethylene molds showed the initial expansion in the early phase of polymerization. This was followed by the rapid contraction in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The polymerization shrinkage in tooth samples was generally lower than in the mold samples. 3. The generally lower amount of linear polymerization shrinkage was observed in compomer and plasma arc curing unit group when compared to composite and conventional curing unit. 4. The higher compressive strength values was found in composite groups regardless curing methods. The results of this study strongly support the application of plasma arc system and fluoride-containing compomer in the field of clinical pediatric dentistry claiming its effectiveness in curing the esthetic dental materials and the anticariogenic capacity.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.22 no.3
• /
• pp.319-329
• /
• 2000

Prediction of the soft tissue changes following hard tissue movement is very important from the esthetic view point for patients who have orthognathic surgery. There are many cephalometric analysis of facial bone and soft tissue on the lower lip and chin region but few soft tissue analysis on the midface after mandibular setback surgery. This study was performed to obtain whether the mandibular posterior movement has influence on the midface and the predictable ratio of post-operative measurement values of the soft tissue changes following mandibular setback surgery. Fifteen patients (8 males and 7 females) who had undergone mandibular setback surgery were selected and analyzed the soft tissue movement on the upper lip and the cheek region. Post-operative changes of the soft tissue measurements after mandibular surgery were examined on pre- and post-operative cephalometrics and the ratio of changes were analyzed after drawing the reference line on the face with the barium sulfate solution. The reference lines were perpendicular to the intercanthal line from infraorbital foramen and lateral canthus. The results obtained were as follows : 1. There were tendancy of anterior movement of soft tissue adjacent the nose after mandibular surgery 2. There were incerased tendancy of the amount of anterior movement from the nasal crease to the cheek region. 3. The amount of anterior movement of the soft tissue was larger below the palatal plane compared with above the palatal plane in the cheek region. 4. The upper lip length was increased and moved posterior direction after mandibular setback surgery 5. The lower lip was moved posterior direction by posterior movement of the mandibular structure 6. Soft tissue of the midface around the nose moved anterior direction after mandibular setback surgery but there was no correlation between the amount of mandibular setback and the amount of the soft tissue changes

• Restorative Dentistry and Endodontics
• /
• v.25 no.1
• /
• pp.17-40
• /
• 2000

Resin cements are used for cementing indirect esthetic restorations such as resin or porcelain inlays. Because of its limitations in curing of purely light cured resin cements due to attenuation of the curing light by intervening materials, dual cured resin cements are recommended for cementing restorations. The physical properties of resin cements are greatly influenced by the extent to which a resin cures and the degree of cure is an important factor in the success of the inlay. The purpose of this study was to evaluate the influence of porcelain thickness and exposure time on the polymerization of resin cements by measuring the microhardness and the degree of conversion, to investigate the nature of the correlation between two methods mentioned above, and to determine the exposure time needed to harden resin cements through various thickness of porcelain. The degree of resin cure was evaluated by the measurements of microhardness [Vickers Hardness Number(VHN)] and degree of conversion(DC), as determined by Fourier Transform Infrared Spectroscopy(FTIR) on one light cured composite resin [Z-100(Z)] and three dual cured resin cements [Duo cement(D), 3M Resin cement(R), and Dual cement(DA)] which were cured under porcelain discs thickness of 0mm, 1mm, 2mm, 3mm with light exposure time of 40sec, 80sec, 120sec, and regression analysis was performed to determine the correlation between VHN and DC. In addition, to determine the exposure time needed to harden resin cements under various thickness of porcelain discs, the changes of the intensity of light attenuated by 1mm, 2mm, and 3mm thickness of porcelain discs were measured using the curing radiometer. The results were obtained as follows ; 1. The values of microhardness and the degree of conversion of resin cements without intervening porcelain discs were 31~109VHN and 51~63%, respectively. In the microhardness Z was the highest, followed by R, D, DA. In the degree of conversion, D and DA was significantly greater than Z and R(p<0.05). 2. The microhardness and the degree of conversion of the resin cements decreased with increasing thickness of porcelain discs, and increased with increasing exposure time, D and R showed great variation with inlay thickness and exposure time, whereas, DA showed a little variation. 3. The intensity of light through 1mm, 2mm, and 3mm porcelain inlays decreased by 0.43, 0.25, and 0.14 times compared to direct illumination, and the respective needed exposure times are 53 sec, 70 sec, and 93 sec. In D and R, 40 sec of light irradiation through 2mm porcelain disc and 80 sec of light irradiation through 3mm porcelain disc were not enough to complete curing. 4. The microhardness and the degree of conversion of the resin cements showed a positive correlationship(R=0.791~0.965) in the order of R, D, Z, DA. As the thickness of porcelain discs increased, the decreasing pattern of microhardness was different from that of the degree of conversion, however.

• The Journal of Advanced Prosthodontics
• /
• v.13 no.6
• /
• pp.361-372
• /
• 2021

PURPOSE. To improve the clinical effects of complete denture use and simplify its clinical application, a digital complete denture restoration workflow (Functional Suitable Digital Complete Denture System, FSD) was proposed and preliminary clinical evaluation was done. MATERIALS AND METHODS. Forty edentulous patients were enrolled, of which half were treated by a prosthodontic chief physician, and the others were treated by a postgraduate student. Based on the primary impression and jaw relation obtained at the first visit, diagnostic denture was designed and printed to create a definitive impression, jaw relation, and esthetic confirmation at the second visit. A redesigned complete denture was printed as a mold to fabricate final denture that was delivered at the third visit. To evaluate accuracy of impression made by diagnostic denture, the final denture was used as a tray to make impression, and 3D comparison was used to analyze their difference. To evaluate the clinical effect of FSD, visual analogue scores (VAS) were determined by both dentists and patients. RESULTS. Two visits were reduced before denture delivery. The RMS values of 3D comparison between the impression made via diagnostic dentures and the final dentures were 0.165 ± 0.033 mm in the upper jaw and 0.139 ± 0.031 mm in the lower jaw. VAS ratings were between 8.5 and 9.6 in the chief physician group, while 7.7 and 9.5 in the student group; there was no statistical difference between the two groups. CONCLUSION. FSD can simplify the complete denture restoration process and reduce the number of visits. The accuracy of impressions made by diagnostic dentures was acceptable in clinic. The VASs of both dentists and patients were satisfied.