Fracture Load of Metal, Zirconia and Polyetheretherketone Posterior CAD-CAM Milled Fixed Partial Denture Frameworks

The aim of this study was to investigate the load to fracture and fracture pattern of prosthetic frameworks for tooth-supported fixed partial dentures (FPDs) fabricated with different subtractive computer-aided design and computer-aided manufacturing (CAD-CAM) materials. Materials and Methods: Thirty standardized specimens with two abutments were fabricated to receive three-unit posterior FDP frameworks with an intermediate pontic. Specimens were randomly divided into three groups (n = 10 each) according to the material: group 1 (MM)—milled metal; group 2 (L)—zirconia; and group 3 (P)—Polyetheretherketone (PEEK). The specimens were thermo-cycled and subjected to a three-point bending test until fracture using a universal testing machine (cross-head speed: 1 mm/min). Axial compressive loads were applied at the central fossa of the pontics. Data analysis was made using one-way analysis of variance, Tamhane post hoc test, and Weibull statistics (α = 0.05). Results: Significant differences were observed among the groups for the fracture load (p < 0.0001). MM frameworks showed the highest fracture load values. The PEEK group registered higher fracture load values than zirconia samples. The Weibull statistics corroborated these results. The fracture pattern was different among the groups. Conclusions: Milled metal provided the highest fracture load values, followed by PEEK, and zirconia. However, all tested groups demonstrated clinically acceptable fracture load values higher than 1000 N. PEEK might be considered a promising alternative for posterior FPDs.

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Different fabrication techniques of implant-supported prostheses

Brazilian Journal of Oral Sciences ◽

10.20396/bjos.v18i0.8657254 ◽

2019 ◽

Vol 18 ◽

pp. e191573

Author(s):

Silas Monteiro Borges ◽

Stephanie Francoi Poole ◽

Izabela Cristina Maurício Moris ◽

Aloísio Oro Spazzin ◽

Adriana Cláudia Lapria Faria ◽

...

Keyword(s):

Mechanical Behavior ◽

Computer Aided Design ◽

Fracture Load ◽

Fracture Pattern ◽

Thermomechanical Cycling ◽

Significant Difference ◽

Computer Aided ◽

Before And After ◽

Cad Cam ◽

Manufacturing Techniques

Aim: This study evaluated the mechanical behavior of implant-supported crowns obtained by different fabrication technique after thermomechanical cycling. Methods: Thirty-two external hexagon dental implants were divided into four groups (n=10): CC – conventional casting with torch; EI – electromagnetic induction casting; PL – plasma casting; and CAD-CAM – milling through computer-aided design and computer-aided manufacturing. Vickers microhardness of the specimens were made before and after the thermomechanical cycling, and then subjected to fracture load. Fracture pattern was evaluated. Results: No significant difference was observed comparing the microhardness before and after thermomechanical cycling. CAD-CAM group presented significant lower microhardness than the other groups. No significant statistical difference was showed on fracture load between the groups. The CAD-CAM and PL presented lower number of failure by plastic deformation. Conclusion: The manufacturing techniques affected the mechanical behavior and the failure pattern of implant-supported crowns tested.

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Fabricated CAD/CAM Post-Core Using Glass Fiber-Reinforced Resin Shows Innovative Potential in Restoring Pulpless Teeth

Materials ◽

10.3390/ma14206199 ◽

2021 ◽

Vol 14 (20) ◽

pp. 6199

Author(s):

Naoko Suzaki ◽

Satoshi Yamaguchi ◽

Eriko Nambu ◽

Ryousuke Tanaka ◽

Satoshi Imazato ◽

...

Keyword(s):

Computer Aided Design ◽

Fracture Resistance ◽

Testing Machine ◽

Fracture Load ◽

Resistance Test ◽

Fiber Reinforced ◽

Fiber Post ◽

Clinical Issue ◽

Computer Aided ◽

Cad Cam

The prevention of root fractures of pulpless teeth is an important clinical issue to maintain healthy teeth through lifetime. The aim of this study was to examine a clinically effective treatment method for strengthening vulnerable pulpless teeth using CAD/CAM (computer-aided design/computer-aided manufacturing) fiber-reinforced post-core by conducting a fracture resistance test. A post-core made with a fiber-reinforced resin disk TRINIA (TR, SHOFU, Kyoto, Japan) was fabricated using a CAD/CAM system. The fiber-layer orientation of the CAD/CAM post-core was parallel to the axis of the restored tooth. A post-core using a conventional composite and a fiber post (CF) was also prepared. A fracture resistance test of teeth restored with the post-cores and zirconia crowns was conducted using a universal testing machine, and fracture patterns were identified by micro-CT observation. The fracture load of the roots restored with TR was 1555.9 ± 231.8 N, whereas that of CF was 1082.1 ± 226.7 N. The fracture load of TR was 43.8% that was significantly higher than that of CF (Student’s t-test, p < 0.05). The restored teeth with CAD/CAM resin post-core were found to be repairable even after fracture. These results suggest that the CAD/CAM indirect fiber post-core has the potential to strengthen the vulnerable pulpless teeth.

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Structural Integrity Evaluation of Large MOD Restorations Fabricated With a Bulk-Fill and a CAD/CAM Resin Composite Material

Operative Dentistry ◽

10.2341/18-013-l ◽

2019 ◽

Vol 44 (3) ◽

pp. 312-321 ◽

Cited By ~ 2

Author(s):

C Papadopoulos ◽

D Dionysopoulos ◽

K Tolidis ◽

P Kouros ◽

E Koliniotou-Koumpia ◽

...

Keyword(s):

Computer Aided Design ◽

Fracture Resistance ◽

Structural Integrity ◽

Resin Composite ◽

Testing Machine ◽

Fracture Load ◽

Chi Square ◽

Significance Level ◽

Computer Aided ◽

Cad Cam

SUMMARY Aims: To evaluate the effect of two composite restorative techniques (direct bulk fill vs indirect CAD/CAM) on the fracture resistance and mode of fracture of extended mesio-occlusal-distal (MOD) cavity preparations. Methods: Fifty-one sound human mandibular third molars were divided into three groups (n=17). Extended bucco-lingual MOD cavities were prepared. Teeth in group 1 were restored with a bulk-fill resin composite (Filtek Bulk-Fill Posterior Restorative), teeth in group 2 were restored with composite computer-aided design/computer-aided manufacturing (CAD/CAM) inlays (Lava Ultimate), and teeth in group 3 served as control and remained intact. All specimens were submitted to thermocycling, and a fracture resistance test was performed using a Universal testing machine (0.5 mm/min). Mode of fracture was classified into five types. One-way analysis of variance and the Duncan test were used to analyze the fracture load data at a significance level of α = 0.05. A chi-square test was used for the analysis of fracture mode between the restorative groups. Results: Statistical analysis showed significant differences in fracture resistance among the experimental groups. The teeth restored with the bulk-fill composite exhibited lower fracture resistance (1285.3±655.0 N) when compared to the teeth restored with the composite CAD/CAM inlays (1869.8±529.4 N) (p<0.05). Mode of fracture showed the same distribution between the restorative groups. Conclusions: Although both types of restorations failed at loads larger than those found in the oral cavity, the CAD/CAM composite inlays increased the fracture resistance of teeth with large MOD cavities when compared to direct bulk-fill composite restorations. The majority of fracture types were intraorally repairable for both restorative techniques.

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Fracture Resistance and Microleakage of Endocrowns Utilizing Three CAD-CAM Blocks

Operative Dentistry ◽

10.2341/13-143-l ◽

2015 ◽

Vol 40 (2) ◽

pp. 201-210 ◽

Cited By ~ 42

Author(s):

HM El-Damanhoury ◽

RN Haj-Ali ◽

JA Platt

Keyword(s):

Fracture Mode ◽

Computer Aided Design ◽

Fracture Resistance ◽

Testing Machine ◽

Resin Cement ◽

Blue Dye ◽

Endodontically Treated Teeth ◽

Modes Of Failure ◽

Computer Aided ◽

Cad Cam

SUMMARY This study assessed marginal leakage and fracture resistance of computer-aided design/computer-aided manufacturing (CAD/CAM) fabricated ceramic crowns with intracoronal extensions into the pulp chambers of endodontically treated teeth (endocrowns) using either feldspathic porcelain (CEREC Blocks [CB], Sirona Dental Systems GmbH, Bensheim, Germany), lithium disilicate (e.max [EX], Ivoclar Vivadent, Schaan, Liechtenstein), or resin nanoceramic (Lava Ultimate [LU], 3M ESPE, St Paul, MN, USA).). Thirty extracted human permanent maxillary molars were endodontically treated. Standardized preparations were done with 2-mm intracoronal extensions of the endocrowns into the pulp chamber. Teeth were divided into three groups (n=10); each group was restored with standardized CAD/CAM fabricated endocrowns using one of the three tested materials. After cementation with resin cement, specimens were stored in distilled water at 37°C for one week, subjected to thermocycling, and immersed in a 5% methylene-blue dye solution for 24 hours. A compressive load was applied at 35 degrees to long axis of the teeth using a universal testing machine until failure. Failure load was recorded, and specimens were examined under a stereomicroscope for modes of failure and microleakage. Results were analyzed using one-way analysis of variance and Bonferroni post hoc multiple comparison tests (α=0.05). LU showed significantly (p<0.05) higher fracture resistance and more favorable fracture mode (ie, fracture of the endocrown without fracture of tooth) as well as higher dye penetration than CB and EX. In conclusion, although using resin nanoceramic blocks for fabrication of endocrowns may result in better fracture resistance and a more favorable fracture mode than other investigated ceramic blocks, more microleakage may be expected with this material.

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Fracture Strength and Precision of Fit of Implant-Retained Monolithic Zirconia Crowns

Journal of Oral Implantology ◽

10.1563/aaid-joi-d-17-00249 ◽

2018 ◽

Vol 44 (5) ◽

pp. 330-334 ◽

Cited By ~ 2

Author(s):

Pauliina Moilanen ◽

Jenni Hjerppe ◽

Lippo V. J. Lassila ◽

Timo O. Närhi

Keyword(s):

Fracture Strength ◽

Computer Aided Design ◽

Testing Machine ◽

Implant Surface ◽

Computer Aided ◽

Cad Cam ◽

Zirconia Crowns ◽

Failure Loads ◽

Monolithic Zirconia ◽

Aided Design

New monolithic zirconia materials can be used to fabricate full-contour fixed dental prostheses with the computer-aided design/computer-aided manufacturing (CAD/CAM) method. The aim of this study was to examine the fracture strength and precision of fit of screw-retained monolithic zirconia crowns made directly on implants or by cementing on prefabricated titanium (Ti) bases. Monolithic screw-retained implant crowns (n = 6) were produced by CAD/CAM method using partially (PSZ) and fully stabilized (FSZ) zirconia. Industrially produced zirconia crowns were used as a reference. A lateral incisor study model was made onto an implant replica. Crowns were produced either directly on the implant or through cementing on a prefabricated titanium base (PSZ+Ti, FSZ+Ti). The crowns were tightened to implant replicas with a torque of 35 Ncm. The gap between the replica and the abutment or crown was measured from ×400 scanning electron microscope images for precision of fit. Mechanical testing until failure was completed with a universal testing machine with loading angle of 45°. Statistical analysis was performed (analysis of variance). Mean (±SD) failure loads were 259 ± 23 (PSZ), 140 ± 13 (FSZ), 453 ± 25 (PSZ+Ti), 439 ± 41 (FSZ+Ti), and 290 ± 39 (Procera). Mean (±SD) gap values were 2.2 ± 0.2 (PSZ), 2.5 ± 1.0 (FSZ), 7.0 ± 1.0 (PSZ+Ti), 7.7 ± 1.6 (FSZ+Ti), and 6.7 ± 1.7 (Procera). Monolithic zirconia crowns with a Ti base clearly show higher fracture strengths than the crowns fixed directly on the implant surface. Better marginal fit can be achieved with direct zirconia crowns than with crowns on a titanium base or industrially produced zirconia crowns.

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Composite vs Ceramic Computer-aided Design/Computer-assisted Manufacturing Crowns in Endodontically Treated Teeth: Analysis of Marginal Adaptation

Operative Dentistry ◽

10.2341/12-208-l ◽

2013 ◽

Vol 38 (6) ◽

pp. 663-673 ◽

Cited By ~ 19

Author(s):

A Ramírez-Sebastià ◽

T Bortolotto ◽

M Roig ◽

I Krejci

Keyword(s):

Computer Aided Design ◽

Computer Assisted ◽

Marginal Adaptation ◽

Crown Group ◽

Endodontically Treated Teeth ◽

Full Coverage ◽

Computer Aided ◽

Cad Cam ◽

Group 2 ◽

Aided Design

SUMMARY Objectives To compare the marginal adaptation between ceramic and composite CEREC crowns in endodontically treated teeth restored with endocrowns or with a short or a long post. Methodology Forty-eight intact maxillary incisors were used. After endodontic treatment, the crowns were sectioned 2 mm coronally to the cemento-enamel junction, which provided a ferrule of 2 mm. The prepared teeth were divided randomly into six groups (n=8). Group 1 was restored with a large fiberglass post, composite core, and ceramic full-coverage computer-aided design/computer-assisted manufacturing (CAD-CAM) crown. Group 2 was restored with a short fiberglass post, composite core, and ceramic full-coverage CAD-CAM crown. Group 3 was restored with a large fiberglass post, composite core, and composite full-coverage CAD-CAM crown (LPCpr). Group 4 was restored with a short fiberglass post, composite core, and composite full-coverage CAD-CAM crown (SPCpr). Groups 5 and 6 were restored with ceramic and composite CEREC machined endocrowns, respectively (EndoCer and EndoCpr). The restored teeth were loaded thermomechanically in a computer-controlled chewing machine. Impressions of each restoration were made in a polyvinylsiloxane material before and after loading. Gold-coated epoxy replicas were prepared for scanning electron microscopy examination at 200× magnification. Results Loading had a statistically significant effect (p<0.05) on the percentage of “continuous margin” in all groups. The LPCpr, SPCpr, and EndoCpr groups showed the highest percentage of continuous margin initially and after loading. The effect of the different post lengths on marginal adaptation was not significant (p>0.05). Conclusion CAD-CAM crowns fabricated from millable composite resin blocks (Paradigm MZ100) offer a superior option to all-ceramic crowns (IPS Empress CAD).

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Comparison of Mechanical Properties of Chairside CAD/CAM Restorations Fabricated Using a Standardization Method

Materials ◽

10.3390/ma14113115 ◽

2021 ◽

Vol 14 (11) ◽

pp. 3115

Author(s):

Myung-Sik Hong ◽

Yu-Sung Choi ◽

Hae-Hyoung Lee ◽

Jung-Hwan Lee ◽

Junyong Ahn

Keyword(s):

Computer Aided Design ◽

Fracture Resistance ◽

Testing Machine ◽

Lithium Silicate ◽

Standardization Method ◽

High Fracture ◽

Failure Patterns ◽

Fracture Failure ◽

Computer Aided ◽

Cad Cam

The aim of this in vitro study was to investigate the fracture resistance, fracture failure pattern, and fractography of four types of chairside computer-aided design/computer-aided manufacturing (CAD/CAM) restoration materials in teeth and titanium abutments fabricated using a standardization method. An artificial mandibular left first premolar prepared for all-ceramic crown restoration was scanned. Forty extracted mandibular molars and cylindrical titanium specimens were milled into a standardized shape. A total of eighty CAD/CAM restoration blocks were milled into a crown and twenty pieces of each lithium disilicate (LS), polymer-infiltrated-ceramic-network (PICN), resin nano ceramic (RNC), and zirconia-reinforced lithium silicate (ZLS) materials were used. Crowns were bonded to abutments, and all specimens underwent thermal cycling treatment for 10,000 cycles. Fracture resistance was measured using a universal testing machine and fracture failure patterns were analyzed using optical microscopy and scanning electron microscopy. Statistical differences were analyzed using appropriate ANOVA, Tukey HSD post hoc tests, and independent sample t-tests (α = 0.05). The results indicated that, in both teeth abutments and titanium abutments, the fracture resistances showed significantly the highest values in LS and the second highest in ZLS (p < 0.05). The fracture resistances based on teeth abutments and titanium abutments were significantly different in all the CAD/CAM restoration materials (p < 0.05). There are statistically significant correlations between the types of materials and the types of abutments (p < 0.05). Each of the different materials showed different fracture failure patterns, and there was no noticeable difference in fractographic analysis. Lithium disilicates and zirconia-reinforced lithium silicates exhibited statistically high fracture resistance, indicating their suitability as restoration materials for natural teeth or implant abutments. There were no distinct differences in the fracture pattern based on the restoration and abutment materials showed that the fracture initiated at the groove where the ball indenter was toughed and propagated toward the axial wall.

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Effect of Different Computer-aided Design/Computer-aided Manufacturing (CAD/CAM) Materials and Thicknesses on the Fracture Resistance of Occlusal Veneers

Operative Dentistry ◽

10.2341/17-131-l ◽

2018 ◽

Vol 43 (5) ◽

pp. 539-548 ◽

Cited By ~ 9

Author(s):

JP Andrade ◽

D Stona ◽

HR Bittencourt ◽

GA Borges ◽

LH Burnett ◽

...

Keyword(s):

Computer Aided Design ◽

Fracture Resistance ◽

Testing Machine ◽

Control Group ◽

Computer Aided Manufacturing ◽

Universal Testing ◽

Computer Aided ◽

Cad Cam ◽

Aided Design

SUMMARY The aim was to evaluate, in vitro, the influence of different computer-aided design/computer-aided manufacturing (CAD/CAM) materials (IPS e.max CAD, Vita Enamic, and Lava Ultimate) and thicknesses (0.6 mm and 1.5 mm) on the fracture resistance of occlusal veneers. Sixty human third molars were prepared to simulate advanced erosion of the occlusal surface, and the teeth were randomly divided into six experimental groups (n=10) according to the material and thickness used to build the veneers. Ten sound teeth formed the control group. The veneers were adhesively luted and submitted to mechanical cyclic loading (1 million cycles at 200-N load). The fracture resistance test was performed in a universal testing machine. The failures were classified as “reparable” and “irreparable.” According to two-way analysis of variance and the Tukey test, the interaction (material × thickness) was significant (p=0.013). The highest fracture resistance was obtained for IPS e.max CAD at a 1.5-mm thickness (4995 N) and was significantly higher compared to the other experimental groups (p<0.05). The lowest fracture resistance was obtained for Vita Enamic at 0.6 mm (2973 N), although this resistance was not significantly different from those for IPS e.max CAD at 0.6 mm (3067 N), Lava Ultimate at 0.6 mm (3384 N), Vita Enamic at 1.5 mm (3540 N), and Lava Ultimate at 1.5 mm (3584 N) (p>0.05). The experimental groups did not differ significantly from the sound teeth (3991 N) (p>0.05). The failures were predominantly repairable. The occlusal veneers of IPS e.max CAD, Vita Enamic, and Lava Ultimate, with thicknesses of 0.6 mm and 1.5 mm, obtained fracture resistances similar to those associated with sound teeth.

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Influence of CAD/CAM Fabrication and Sintering Procedures on the Fracture Load of Full-Contour Monolithic Zirconia Crowns as a Function of Material Thickness

Operative Dentistry ◽

10.2341/19-086-l ◽

2020 ◽

Vol 45 (2) ◽

pp. 219-226 ◽

Cited By ~ 2

Author(s):

M Zimmermann ◽

A Ender ◽

A Mehl

Keyword(s):

Computer Aided Design ◽

Mean Value ◽

Fracture Load ◽

Significance Level ◽

Material Thickness ◽

Computer Aided ◽

Cad Cam ◽

Zirconia Crowns ◽

Monolithic Zirconia

Summary Objective: The purpose of this in vitro study was to analyze the effect of computer-aided design/computer-aided manufacturing (CAD/CAM) fabrication and sintering procedures on the fracture load of monolithic zirconia crowns with different material thicknesses adhesively seated to methacrylate dies fabricated with stereolithography technology. Method: Monolithic zirconia crowns were fabricated from inCoris TZI C material with a chairside CAD/CAM system (CEREC MCXL) comprising three material thicknesses (0.5/1.0/1.5 mm, n=8 each). Two CAD/CAM fabrication procedures (milling, MI; grinding, GR), two chairside sintering procedures (superspeed, SS; speedfire sintering, SF), and one labside sintering procedure (classic, CL) were evaluated. In total, 144 crowns were fabricated. Restorations were adhesively seated to methacrylate dies fabricated with SLA technology. Thermomechanical cycling (TCML) was performed before fracture testing. Loading forces until fracture were registered and statistically analyzed with one-way analysis of variance (ANOVA), post hoc Scheffé test, and three-way ANOVA (α=0.05). Results: Test groups showed statistically significant differences (p<0.05). The highest mean value was found for 1.5-mm crowns of group GR_SF with 3678.6 ± 363.9 N. The lowest mean value was found for group 0.5-mm crowns of group MI_SF with 382.4 ± 30.7 N. There was a significant three-way interaction effect between thickness, sintering, and processing [F(4,126)=9.542; p<0.001; three-way ANOVA, significance level α=0.05]. Conclusions: CAD/CAM fabrication and sintering procedures influence the maximum loading force of monolithic zirconia crowns with different material thicknesses. A material thickness of 0.5 mm should be considered as a critical thickness for monolithic zirconia crown restorations.

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Marginal Gap Evaluation of Metal Onlays and Resin Nanoceramic Computer-Aided Design and Computer-Aided Manufacturing Blocks Onlays

European Journal of Dentistry ◽

10.1055/s-0039-1688740 ◽

2019 ◽

Vol 13 (01) ◽

pp. 017-021

Author(s):

Nor Faharina Abdul Hamid ◽

Wan Zaripah Wan Bakar ◽

Zaihan Ariffin

Keyword(s):

Statistical Analysis ◽

Computer Aided Design ◽

Marginal Gap ◽

Computer Aided Manufacturing ◽

Promising Alternative ◽

Significant Difference ◽

Computer Aided ◽

Cad Cam ◽

Aided Design

Abstract Objective This study was carried out to assess and compare the marginal gap of conventionally used metal onlays and new resin nanoceramic (RNC) (Lava Ultimate block) onlays. Materials and Methods This is an in vitro study using two extracted sound human mandibular molars. One tooth was prepared to receive the metal onlays and another one for the RNC onlays which were fabricated using the computer-aided design and computer-aided manufacturing (CAD/CAM) technology. Twelve metals and 12 ceramic onlays were fabricated before they were placed at their respective preparation and examined under the Leica stereomicroscope, M125C (Leica Microsystems, Wetzlar, Germany) for a marginal analysis. The gap width was measured at 10 predefined landmarks which included 3 points on the buccal and lingual surfaces each and 2 points each on the mesial and distal surfaces, respectively. Statistical Analysis Mann–Whitney post hoc test was used for statistical analysis (P ≤ 0.05). Results Overall, the RNC onlays showed significant lower marginal gap with the exception of the landmarks 5 and 6 (on distolingual) and no significant difference at landmark 7 (on midlingual). It was observed that the marginal gap were all within the clinically acceptable limit of 120 μm. Conclusions Based on the results obtained, it can be concluded that the RNC CAD/CAM onlays are a promising alternative to the metal onlays.

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