All-ceramic premolar guiding plate retains resin-bonded fixed partial dentures / 华西口腔医学杂志

OBJECTIVE@#This study aims to investigate the fracture resistance and short-term restorative effects of resin-bonded fixed partial dentures (RBFPDs) made from heat-pressed lithium-disilicate-based glass-ceramic (IPS e.max press) and zirconia ceramic (WIELAND) and retained by all-ceramic guiding plates when used to restore missing mandibular second premolars.@*METHODS@#A total of 64 human mandibular first premolars and first molars were prepared as abutments, then were randomly divided into 4 groups (n=8): E0, heat-pressed ceramic RBFPDs, no cyclic loading; E1, heat-pressed ceramic RBFPDs exposed to 300 000 cycles of dynamic loading; W0, zirconia ceramic RBFPDs, no cyclic loading; and W1, zirconia ceramic RBFPDs exposed to 300 000 cycles of dynamic loading. Fracture strength was tested in a universal testing machine.@*RESULTS@#The medians of fracture strength were 1 242.85 N±260.11 N (E0), 1 650.85 N±206.77 N (W0), 1 062.60 N±179.98 N (E1), and 1 167.61 N±265.50 N (W1). Statistical analysis showed that all the groups exhibited significantly higher fracture strength compared with the maximum bite force in the premolar region (360 N; P0.05). Significant statistical differences were found between the zirconia ceramic groups (W0 and W1, P0.05) after dynamic loading.@*CONCLUSIONS@#The RBFPDs retained by all-ceramic guiding plates exhibited promising fracture properties and optimal short-term restorative effects when used to restore missing mandibular second premolars.

Modified resin-bonded fixed partial dentures utilizing tooth undercuts: a clinical case study / 대한치과보철학회지

PURPOSE: The object of this clinical study was to evaluate the short-term outcome of modified resin-bonded fixed partial dentures which utilizes the original tooth undercuts and different path of insertion of components. MATERIALS AND METHODS: 71 units of modified RBFPDs that were used in 21 patients at the Department of Prosthodontics, College of Dentistry, Yonsei University were evaluated. The follow-up period was up to 25 months, the mean being 7 months. Survival rate, mobility, percussion, probing depth, bleeding on probing, plaque index was recorded and radiographs were taken to monitor alveolar bone loss. RESULTS & CONCLUSION: Within the limits of this short term retrospective study, it was concluded that: 1. No mechanical failure such as debonding or fracture of the framework was found during the follow-up period. 2. The periodontal apparatus was stable and no clinical change was observed after prosthetic treatment. 3. No significant marginal bone loss was found in the radiographic evaluation.

Comparison of stress patterns and displacement in conventional cantilever fixed partial denture with resin bonded cantilever fixed partial denture: A finite element analysis.

Aim: This study aims to analyze the stress patterns and displacement in the cantilever resin bonded fixed partial denture (RBFPD) and compare it with the conventional cantilever fixed partial denture using 3-D finite element analysis. Also, the effect of cement on the displacement and stress patterns in conventional cantilever fixed partial denture was to be analyzed. Materials and Methods: Three-dimensional models were prepared layer wise to depict the conventional cantilever and the cantilever RBFPD. Once the models were made, the material properties were assigned and divided into three groups. (2-conventional cantilever with resin cement, 1- conventional cantilever with GIC cement and 3-resin bonded cantilever with resin cement). Load was applied in vertical as well as lateral directions and the stress patterns along with displacement were analyzed. Results: The results revealed that the von Mises stresses in all the three groups were found to be almost equal under vertical loading. Under lateral loading, the stress was more in cantilever RBFPD. Displacement in all the three axes was significantly less in the cantilever RBFPD. Conclusion: Stress concentration in the lateral direction in cantilever RBFPD was found to be higher than the cantilever conventional group. Displacement in X, Y and Z axes was less in cantilever RBFPD.

Dislodgement resistance of modified resin-bonded fixed partial dentures utilizing tooth undercuts: an in vitro study

STATEMENT OF PROBLEM: Over the years, resin-bonded fixed partial dentures (RBFPDs) have gone through substantial development and refinement. Several studies examined the biomechanics of tooth preparation and framework design in relation to the success rate of RBFPDs and considered retention and resistance form essential for increase of clinical retention. However, these criteria required preparations to be more invasive, which violates not only the original intentions of the RBFPD, but may also have an adverse effect on retention due to loss of enamel, an important factor in bonding. PURPOSE: The object of this in vitro study was to compare the dislodgement resistance of the new types of RBFPDs, the conventional three-unit fixed partial denture, and conventional design of RBFPD (Maryland bridge). MATERIAL AND METHODS: Fifty resin mandibular left second premolars and second molars were prepared on dentiforms, according to the RBFPD design. After model fabrication (five group, n = 10), prostheses were fabricated and cemented with zinc phosphate cement. After cementation, the specimens were subjected to tensile loading at a cross head speed of 4 mm/min in a universal testing machine. The separation load was recorded and analyzed statistically using one-way analysis of variance followed by Duncan's multiple range test. RESULTS: Group V, the pin-retained RBFPDs, had the highest mean dislodgement resistance, whereas specimens of group II, the conventional RBFPDs, exhibited a significantly lower mean dislodgement resistance compared to the other 4 groups (P .05). Group V had the highest mean MPa (N/mm2) (P .05). CONCLUSION: Within the limits of the design of this in vitro study, it was concluded that: 1. The modified RBFPDs which utilizes the original tooth undercuts and requires no tooth preparation, compared with the conventional design of RBFPDs, has significantly high dislodgement resistance (P .05). 3. The pin-retained FPDs showed a high dislodgement resistance compared to the conventional three-unit FPDs (P < .05).

Construction of 3-dimensional finite element model of resin-bonded-fixed-partial dentures by dimensional laser scanning and reverse engineering / 实用口腔医学杂志

Objective:To explore a method for setting up three dimensional finite element model of posterior glass fiber reinforced composite resin-bonded-fixed-partial dentures (GFRC-RBFPD) including restoration, periodontal tissue and alveolar bone. Methods:A stone model was fabricated including abutments and pontic of restoration, then it was scanned with laser scanner. Acquired data were integrated in Geomagic 5.0. Basic 3D geometric model was established. Different parts of abutement and prosthesis were designed in I-DEAS 10 NX Series and Geomagic, then periodontal tissue and alveolar bone were set up in Geomagic 5.0. Completed 3D geometric model was input into MSC.Marc Mentat 2003 for mesh generation. Boundary conditions were defined. Model was calculated in Mentat 2003. Results:3D geometric model and finite element model including GFRC-RBFPD, abutments, periodontal membrane and bone (bone lamina dura,cortical bone and cancellous bone) were established.Little contour information was lost, comparability between models was improved.Conclusion:The 3-dimensional laser scanning technique, CAD and mesh generation technique are effective in the establishment of 3-dimensional finite element model of GFRC-RBFPD.