PURPOSE: The design of the attachment must provide an optimum stress distribution around the implant. In this study, for implant overdentures with a bar/clip attachment or a locator attachment, the stress transmitted to the implant in accordance with the change in the denture base length and the vertical pressure was measured and analyzed. MATERIALS AND METHODS: Test model was created with epoxy resin. The strain gauges made a tight contact with implant surfaces. A universal testing machine was used to exert a vertical pressure on the mandibular implant overdenture and the strain rate of the implants was measured. RESULTS: Means and standard deviations of the maximum micro-deformation rates were determined. 1) Locator attachment: The implants on the working side generally showed higher strain than those on the non-working side. Tensile force was observed on the mesial surface of the implant on the working side, and the compressive force was applied to the buccal surface and on the surfaces of the implant on the non-working side. 2) Bar/clip attachment: The implants on the both non-working and working sides showed high strain; all surfaces except the mesial surface of the implant on the non-working side showed a compressive force. CONCLUSION: To minimize the strain on implants in mandibular implant overdentures, the attachment of the implant should be carefully selected and the denture base should be extended as much as possible.
Denture Bases* ; Denture, Overlay* ; Dentures*

No abstract available.
Denture Bases* ; Dentures*

The purpose of this study was to evaluate the effect of proportional thickness of various reline materials on the transverse strength of denture base. The denture base resin used in this study was Vertex RS (Dentimex Zeist., Holland). The reline resins used were Tokuso rebase normal set (Tokuyama Corp., Japan), Rebaron (GC Corp., Japan), KoolinerTM(GC INC., U.S.A). New trulinerTM(Harry J. Bosworth Co., U.S.A). The bulk specimens with 2.5mm thickness of denture base were prepared as the control group. Group 1 was fabricated with 2.0mm thickness of denture base and 0.5mm reline material, group 2 with 1.5:1.0mm. group 3 with 1.0:1.5mm, group 4 with 0.5:2.0mm composition. Measurements of transverse strength were taken for each specimens. The results were as follows: 1. Regardless of the reline resin type, the transverse strength of denture base was decreased after reline procedure. 2. The transverse strength according to the reline resin type was decreased in the following order : Rebaron, Tokuso rebase, Kooliner, and then New truliner and there was a significant difference among the reline materials (P<0.05). 3. The strength of the relined denture base generally decreased as the proportional thickness of the denture reline material increased. These results suggest that increasing the proportional thickness of the reline material progressively decreased the strength of the relined denture base. Thus, the denture base should not be unnecessarily altered during the reline procedure.
Denture Bases* ; Dentures*

No abstract available.
Coffee* ; Denture Bases* ; Dentures*

No abstract available.
Denture Bases* ; Dentures*

No abstract available.
Denture Bases* ; Dentures*

PURPOSE: The aim of this study was to evaluate the effects of relining materials on the flexural strength of relined thermoplastic denture base resins (TDBRs). MATERIALS AND METHODS: For shear bond strength testing, 120 specimens were fabricated using four TDBRs (EstheShot-Bright, Acrytone, Valplast, Weldenz) that were bonded with three autopolymerizing denture relining resins (ADRRs: Vertex Self-Curing, Tokuyama Rebase, Ufi Gel Hard) with a bond area of 6.0 mm in diameter and were assigned to each group (n=10). For flexural strength testing, 120 specimens measuring 64.0×10.0×3.3 mm (ISO-1567:1999) were fabricated using four TDBRs and three ADRRs and were assigned to each group (n=10). The thickness of the specimens measured 2.0 mm of TDBR and 1.3 mm of ADRR. Forty specimens using four TDBRs and 30 specimens using ADRRs served as the control. All specimens were tested on a universal testing machine. For statistical analysis, Analysis of variance (ANOVA) with Tukey's test as post hoc and Spearman's correlation coefficient analysis (P=.05) were performed. RESULTS: Acry-Tone showed the highest shear bond strength, while Weldenz demonstrated the lowest bond strength between TDBR and ADRRs compared to other groups. EstheShot-Bright exhibited the highest flexural strength, while Weldenz showed the lowest flexural strength. Relined EstheShot-Bright demonstrated the highest flexural strength and relined Weldenz exhibited the lowest flexural strength (P < .05). Flexural strength of TDBRs (P=.001) and shear bond strength (P=.013) exhibited a positive correlation with the flexural strength of relined TDBRs. CONCLUSION: The flexural strength of relined TDBRs was affected by the flexural strength of the original denture base resins and bond strength between denture base resins and relining materials.
Denture Bases ; Denture Liners ; Denture Rebasing ; Dentures

STATEMENT OF PROBLEM: For the long-term success of removable partial dentures, the bonding between metal framework and denture base resin is one of the important factors. To improve bonding between those, macro-mechanical retentive form that is included metal framework design has been generally used. However it has been known that sealing at the interface between metal framework and denture base resin is very weak, because this method uses mechanical bonding. PURPOSE: Many studies has been made to find a simple method which induces chemical bond, now various bonding system is applied to clinic. In this experiment, shear bond strengths of heat-cured denture base resin to the surface-treated Co-Cr alloy were measured before and after thermocycling. Chemically treated groups with Alloy Primer(TM), Super-Bond C&B(TM), and tribochemically treated group with Rocatec(TM) system were compared to the beadtreated control group. The data were analyzed with two-way ANOVA. RESULT: 1. Shear bond strength of bead-treated group is highest, and Alloy Primer(TM) treated group, Super-Bond C&B(TM) treated group, Rocatec(TM) system treated group were followed. Statistically significant differences were found in each treated group(p<0.05). 2. Surface treatment and thermocycling affected shear bond strength(p<0.05), however there was no interaction between two factors(p>0.05). 3. Shear bond strengths of bead-treated group and Alloy Primer(TM) treated group showed no statistically significant difference before and after thermocycling(p>0.05), and those of Super-Bond CBTM treated group and RocatecTM system treated group showed statistically significant difference after thermocycling(p<0.05).
Alloys* ; Denture Bases* ; Denture, Partial, Removable ; Dentures*

STATEMENT OF PROBLEM: Fracture and dimensional change of an acrylic resin denture are a rather common occurrence. PURPOSE: The purpose of this study was to compare differences in dimensional changes and flexural strength of separate maxillary complete dentures after immediate deflasking by injection molding and conventional compression processing. MATERIAL AND METHOD: To evaluate dimensional stability, the maxillary dentures were fabricated by using different materials and methods. Lucitone 199(Dentsply Trubyte, york, pennsylvania, USA) and Vertex(Dentimex, zeist, Netherlands) were used as materials. Compression and injection packing methods were used as processing methods. The impression surface of the dentures was measured by 3D Scanning System(PERCEPTRON, USA) and overlapped original impression surface of the master cast. To evaluate flexural strength, resin specimens were made according to the different materials, powder/liquid ratio and processing methods. Flexural strength of the complete resin specimens (64mm*10mm*3.3mm) were measured by INSTRON 467.(INSTRON, England) The data was analyzed by ANOVA, t-test and Tukey test.(p<.05 level of significance) RESULT: The results were as follows: 1. There was no significant differences between master model and denture base for each group in overall dimensional changes. 2. Palatal area was more stable than flange or alveolar area in dimensional stability. but, there was no significant differences among each area. 3. Materials and power/liquid ratio had an effect on flexural strength.(p<.05) Especially materials was most effective.(p<.05) 4. Lucitone 199(powder/liquid ratio followed by manufacturer's direction) showed higher flexural strength than Vertex. CONCLUSION: Dimensional stability or flexural strength are affected by materials rather than packing techniques.
Denture Bases ; Denture, Complete* ; Dentures ; Fungi* ; Pennsylvania

The purpose of this study was to evaluate the effects of four metal surface treatments on the shear bond strength of reline resin to Ni-Cr alloy. The denture base metal used in this study was Ni-Cr alloy(Ticonium Premium 100, Ticonium Co., U.S.A.). 120 specimens were divided into five metal surface treatments:sandblasting only, MR.BOND(Tokuyama Corp., Japan), Cesead Opaque Primer(Kuraray Co., Japan), METALPRIMER II(GC Corp., Japan)and Super-Bond C&B(Sun Medical Co., Japan) after sandblasting. They were bonded with one of three reline resins: Mild Rebaron(GC Corp., Japan), Mild Rebaron LC(GC Corp., Japan) and Meta Base M(Sun Medical Co.,Japan).Then they were thermocycled 1,000 times at temperature of 4 celsius degrees and 60 celsius degrees. The shear bond strengths were measured using the universal testing machine(Instron,Model 4301, England)with a cross-head speed of 2 mm/min. The results were as follows: 1.All metal primers and adhesive cement significantly improved the bond strength of reline resin to Ni-Cr alloy compared with sandblasted specimens. 2.In Mild Rebaron and Mild Rebaron LC,Cesead Opaque Primer showed the highest bond strength, but the differences among Cesead Opaque Primer,MR.BOND and METALPRIMER II were not significant.The bond strength of Cesead Opaque Primer was significantly different with that of Super-Bond C&B. 3.In Meta Base M,Super-Bond C&B showed the highest bond strength,but there was no difference between Super-Bond C&B and three metal primers. 4.There was no difference in the bond strength between Mild Rebaron and Mild Rebaron LC when metal surface was treated with the same method. 5.The bond strengths of Mild Rebaron and Mild Rebaron LC treated with Cesead Opaque Primer were higher than that of Meta Base M.The bond strengths of Mild Rebaron treated with MR. BOND and METALPRIMER II was higher than that of Meta Base M.However,there was no difference among three reline resins treated with Super-Bond C&B.
Adhesives ; Alloys ; Denture Bases* ; Dentures*