Polyetheretherketone Framework Research Articles

Effect of surface treatment and resin cement type on the bond strength of polyetheretherketone to lithium disilicate ceramic

BackgroundThis study aims to evaluate the effect of surface treatment and resin cement on the shear bond strength (SBS) and mode of failure of polyetheretherketone (PEEK) to lithium disilicate ceramic (LDC). This is suggested to study alternative veneering of PEEK frameworks with a ceramic material.Methodseighty discs were prepared from PEEK blank and from lithium disilicate ceramic. Samples were divided into four groups according to surface treatment: Group (A) air abraded with 110 μm Al2O3, Group (AP) air abrasion and primer application, Group (S) 98% sulfuric acid etching for 60 s, Group (SP) Sulfuric acid and primer. Each group was subdivided into two subgroups based on resin cement type used for bonding LDC:1) subgroup (L) self- adhesive resin cement and 2) subgroup (B) conventional resin cement (n = 10). Thermocycling was done for all samples. The bond strength was assessed using the shear bond strength test (SBS). Failure mode analysis was done at 50X magnification with a stereomicroscope. Samples were chosen from each group for scanning electron microscope (SEM). The three-way nested ANOVA followed by Tukey’s post hoc test were used for statistical analysis of results. Comparisons of effects were done utilizing one way ANOVA and (p < 0.05).ResultsThe highest mean of shear bond strength values was demonstrated in Group of air abrasion with primer application using conventional resin cement (APB) (12.21 ± 2.14 MPa). Sulfuric acid groups showed lower shear bond strength values and the majority failed in thermocycling especially when no primer was applied. The failure mode analysis showed that the predominant failure type was adhesive failure between cement and PEEK, while the remaining was mixed failure between cement and PEEK.ConclusionThe air abrasion followed by primer application and conventional resin cement used for bonding Lithium Disilicate to PEEK achieved the best bond strength. Primer application did not have an effect when self-adhesive resin cement was used in air-abraded groups. Priming step is mandatory whenever sulfuric acid etching surface treatment is utilized for PEEK.

Effect of different surface roughening treatment on polyether ether ketone and acrylic resin bonding: A pilot study.

As polyether ether ketone (PEEK) is a relatively new material in dentistry, its bonding properties with regard to dental acrylic base materials are not fully known. To ensure the long-term success of removable dentures with a PEEK framework, the base materials must be well bonded to each other. The study aimed to investigate the effects of different kinds of surface roughening treatment on PEEK and acrylic resin bonding. Eighty PEEK specimens (N = 80) were randomly divided into 5 groups (n = 16 per group) and subjected to various surface roughening treatment (control, grinding, sandblasting, tribochemical silica coating (CoJet), and sulfuric acid etching). Heat-polymerized acrylic resin was applied to the treated surfaces of the PEEK specimens. The shear bond strength (SBS) test, environmental scanning electron microscopy (ESEM) analysis and three-dimensional (3D) surface topography analysis were performed. The statistical analysis of the data was conducted using the analysis of variance (ANOVA) and Tukey's multiple comparison test. The one-way ANOVA showed significant differences in the SBS values between the groups (p = 0.001). Sandblasting, tribochemical silica coating and sulfuric acid etching resulted in high SBS values (p = 0.001). The highest SBS values were observed in the sulfuric acid etching group (8.83 ±3.63 MPa), while the lowest SBS values were observed in the control group (3.33 ±2.50 MPa). The additional roughening treatment applied to the PEEK surface increases the bond strength with heat-polymerized acrylic resin.

Suitability and Trueness of the Removable Partial Denture Framework Fabricating by Polyether Ether Ketone with CAD-CAM Technology.

The object of the study was to evaluate the suitability and trueness of the removable partial denture (RPD) framework fabricated by polyether ether ketone (PEEK) with the CAD-CAM technology in vitro. Four different types of dentition defects were selected. In each type, five PEEK RPD frameworks were fabricated by the CAD-CAM technology, while five Co-Cr RPD frameworks were made by traditional casting. The suitability of the framework was evaluated by silicone rubber film slice measurement and the three-dimensional image overlay method. The trueness of the PEEK framework was detected by the three-dimensional image overlay method. Data were statistically analyzed with the use of an independent samples t-test (α = 0.05). The suitability values by silicone rubber film slice measurement of the PEEK group were lower than those of the Co-Cr group in four types, with the differences indicating statistical significance (p < 0.05) in type one, type two, and type four. The suitability values using the three-dimensional image overlay method showed no statistical differences (p > 0.05) between the two groups in four types. The trueness values of the PEEK group were within the allowable range of clinical error. The suitability and trueness of the PEEK RPD framework fabricated by CAD-CAM technology met the requirements of the clinical prosthesis.

Fit Accuracy of Cobalt–Chromium and Polyether Ether Ketone Prosthetic Frameworks Produced Using Digital Techniques: In Vitro Pilot Study

This pilot study aimed to compare the fit accuracy of cobalt–chromium (Co-Cr) and polyether ether ketone (PEEK) removable partial denture frameworks, produced by digital technologies. Two study models of previously prepared Kennedy’s Class I and Class III mandibular dental arches were scanned. For each model, two frameworks were digitally designed and manufactured using a Co-Cr alloy via the selective laser melting (SLM) technique, and using PEEK via the milling technique. A qualitative assessment of the framework’s fit accuracy to the corresponding study models was carried out using calibrated endodontic instruments and image amplification. Best-fit superimpositions between the reference design and the scanned frameworks were performed using the Geomagic Control X version 2018, 3D Systems software, allowing the expression of trueness by calculating the root mean square (RMS) value. Higher fit accuracy was observed for the milled frameworks, with the Class I PEEK framework showing the best fit accuracy to the corresponding model. RMS values were Class I—148.3 μm for Co-Cr and 69.2 μm for PEEK; Class III—107.2 μm for Co-Cr and 59.7 μm for PEEK. In the experimental conditions used, the milled PEEK frameworks showed better fit accuracy and higher trueness than the SLM-printed Co-Cr ones in both Kennedy classes.

Evaluation and comparison of retention and patient satisfaction with milled polyetheretherketone versus metal maxillary obturators

Statement of problemMetal and polyetheretherketone (PEEK) have been used to rehabilitate maxillary defects with obturators, each having advantages and disadvantages. However, patient satisfaction with the obturator retention of each material is unclear. PurposeThe purpose of this crossover clinical study was to compare retention and patient satisfaction between a milled cobalt chromium and a milled PEEK framework, each with a hollow bulb extension in polymethyl methacrylate (PMMA). Material and methodsTwenty patients who had received unilateral total maxillectomy and were treated in the prosthodontic department's maxillofacial clinic were enrolled in this crossover study. Each participant wore 2 different types of obturators for 6 months after insertion. Type CoCr received a milled cobalt chromium framework with a hollow bulb extension in PMMA first, and type Pk received a milled modified PEEK (BioHPP) framework with a hollow bulb extension in PMMA first. Patient satisfaction and retention force were measured immediately, at 3 months, and at 6 months after obturator insertions. The Fischer exact, chi-squared, and Monte Carlo tests were used to compare qualitative data. One-way ANOVA with the post hoc Tukey test was used for pair-wise comparison, and repeated measures ANOVA was used to compare before and after treatment at 3 and 6 months. ResultsNo significant difference was found between types in obturator insertion (P>.999), appearance of the upper lip (P>.999), mouth feeling (P=.301), pronunciation of words (P=.217), and talking in public (P=.589). A significant difference between types was found in speech after 6 months of obturator insertion (P=.016), swallowing liquids and food (P=.04), masticating foods (P=.007), appearance of clasps on anterior teeth (P=.002), satisfaction with appearance (P=.005), or avoidance of family events (P=.014) after 6 months of insertion. Types of obturators showed a statistically significant decrease in retention force with time (P<.001). ConclusionsAlthough the retention force was less with PEEK than with Co-Cr clasps engaging the same undercuts, this retention force was adequate for retaining removable partial dentures. Co-Cr clasps can be considered better than PEEK clasps because they engage the same undercuts regarding loss of retention with time. Quality of life in patients after maxillary resection could be improved by using maxillary obturators. Type Pk was better than type CoCr in terms of esthetics, but the retention of the PEEK obturator after 6 months decreased because of wear, leading to difficulty swallowing food or liquids, mastication, and speech.

Maxillary "All-on-six" treatment using zygomatic implants. Bone loss evaluation by cone beam computed tomography; Three years' follow-up.

To evaluate radiographic changes around six implants (Two posterior zygomatic and four conventional implants) used with fixed detachable restorations in patients with severe maxillary posterior resorption with either Polyether ether ketone (PEEK) or titanium frameworks. Twelve maxillary edentulous patients were rehabilitated with six implants, including two posterior zygomatic and 4 conventionally placed implants for each patient following all-on-six distribution, and opposing mandibular all-on-four implant retained fixed detachable prostheses. A two-stage surgical unloaded healing protocol was performed. According to framework and teeth materials, there were two groups; Group I: CAD-CAM milled framework from modified BioHPP PEEK, bonded to polymethylmethacrylate crowns. Group II: screw-retained CAD-CAM milled framework from titanium, bonded to zirconium crowns. Bone loss evaluation for six implants was performed using cone beam computed tomography at the time of insertion (T0), after one year (T1), and after three years (T2). There was a statistically significant difference in bone loss between PEEK and titanium groups. Less bone loss in PEEK groups around anterior conventional implants at buccal surfaces (P =0.01), at mesial surfaces (P <0.001), at distal surfaces (P <0.001), and zygomatic implants at buccal surfaces (P =0.004), and at palatal surfaces (P =0.003). Within the limitations of the study, the full-arch PEEK and titanium frameworks of fixed-detachable prostheses used with an All-on-Six distribution using zygomatic implants for rehabilitation of maxillary edentulous atrophied posterior arches was a promising treatment approach. Less bone loss was observed with the PEEK framework restorations combined with the PMMA crowns group.

Comparison of intraoral and laboratory scanners to an industrial-grade scanner while analyzing the fabrication trueness of polymer and titanium complete-arch implant-supported frameworks

ObjectivesTo compare the scans of different intraoral scanners (IOSs) and laboratory scanners (LBSs) to those of an industrial-grade optical scanner by measuring deviations of complete-arch implant-supported frameworks from their virtual design file. Material and methodsTen polyetheretherketone (PEEK) and 10 titanium (Ti) complete-arch implant-supported frameworks were milled from a master standard tessellation language (STL) file. An industrial-grade blue light scanner (AT), 2 LBSs (MT and E4), and 3 IOSs (PS, T3, and T4) were used to generate STL files of these frameworks. All STLs were imported into an analysis software (Geomagic Control X) and overall root mean square (RMS) values were calculated. Marginal surfaces of all STL files were then virtually isolated (Medit Link v 2.4.4) and marginal RMS values were calculated. Deviations in scans of tested scanners were compared with those in scans of AT by using a linear mixed effects model (α = 0.05). ResultsWhen the scans of PEEK frameworks were considered, PS and T3 had similar overall RMS to those of AT (p ≥ .076). However, E4 and T4 had higher and MT had lower overall RMS than AT (p ≤ .002) with a maximum estimated mean difference of 13.41 µm. When the scans of Ti frameworks were considered, AT had significantly lower overall RMS than tested scanners (p ≤ .010) with a maximum estimated mean difference of 31.35 µm. Scans of tested scanners led to significantly higher marginal RMS than scans of AT (p ≤ .006) with a maximum estimated mean difference of 53.90 µm for PEEK and 40.50 µm for Ti frameworks. ConclusionOnly the PEEK framework scans of PS and T3 led to similar overall deviations to those of AT. However, scans of all tested scanners resulted in higher marginal deviations than those of AT scans. Clinical SignificanceScans performed by using PS and T3 may be alternatives to those of tested reference industrial scanner AT, for the overall fabrication trueness analysis of complete-arch implant-supported PEEK frameworks.

Marginal fit and fracture resistance of polyetheretherketone, zirconia, and titanium implant-supported prosthesis frameworks for a partially edentulous arch after thermomechanical aging

Although polyetheretherketone (PEEK) and zirconia (Zir) have been used as implant-supported prosthesis (ISP) frameworks, the long-term effects of thermomechanical aging on the marginal fit and fracture resistance of PEEK and Zir ISP frameworks with titanium (Ti) bases for patients with a partially edentulous arch are not clear. The purpose of this in vitro study was to determine the marginal fit and fracture resistance of PEEK and Zir ISP frameworks with Ti bases and Ti ISP frameworks for partially edentulous arches after aging. A total of 30 ISP epoxy resin casts were obtained from a typodont with 1 straight implant (Nobel Biocare) in the mandibular right canine region and 1 implant with a 30-degree distal tilt in the mandibular right first molar region. All frameworks (n=10) were fabricated on their own epoxy resin cast with multiunit abutment replicas by using a computer-aided design and computer-aided manufacturing system (exocad-Yenadent). The PEEK and Zir frameworks were fabricated with Ti-bases. Primer (MKZ) and resin cement (DTK adhesive) were used to cement the frameworks to the Ti-bases under a static load of 10N. After thermomechanical aging (1.2×106 cycles, 120N, 5°C-55°C), marginal gaps between the Ti-bases and cemented frameworks and vertical and passive fits between the Ti-bases and framework and multi-unit abutments were measured by using a stereomicroscope (Euromex) at ×100 magnification. Fracture resistances and types were then determined by using a universal test machine and a stereomicroscope at ×40 magnification. Data were analyzed by using 1-way analysis of variance (ANOVA) and the Tukey HSD and Fisher-Freeman-Halton tests (α=.05). The marginal gaps of the PEEK and Zir frameworks were respectively 83.5 ±27.1 and 81.8 ±17.8µm. PEEK (23.7 ±4.6) and Zir (32.9 ±8.7) had a better vertical fit (µm) than Ti (52.5 ±10.6) (P<.001). Zir (49.3 ±16.2) (P<.001) and PEEK (70.9 ±19.6) (P>.05) frameworks had better passive fit (µm) than Ti (91.3 ±24.2). Ti had the highest mean fracture resistance (N) (14800.2 ±3442.3) followed by Zir (7318.7 ±1385.1) and PEEK (3448.9 ±486.6) (P<.001). Fracture types were different in different groups (P<.001). The PEEK and Zir frameworks with Ti baseshad better vertical and passive fit than the Ti frameworks. All ISP frameworks represented mean marginal fit below 92µm and withstood physiologic occlusal forces after thermomechanical aging.

Effect of coping materials zirconia or polyetheretherketone with different techniques of fabrication on vertical marginal gap and fracture resistance of posterior crowns with composite veneering

BackgroundInsufficient research has been conducted in the literature assessing the performance of zirconia and polyetheretherketone (PEEK) crowns in relation to the essential requirements of successful restorations, such as fracture resistance or margin adaptation. The purpose of this study was to evaluate the effect of the coping materials zirconia or PEEK with different fabrication techniques on the vertical marginal gap and fracture resistance of posterior crowns with composite veneering.MethodsCeramic copings (n = 18) restoring mandibular first molar were fabricated from zirconia (Zircon.x, Presidentdental, Germany), milled PEEK (PEEK CAD) (breCAM.BioHPP, Bredent, Germany) and pressed PEEK (PEEK Press) (BioHPP Granules, Bredent, Germany) six specimens each (n = 6). The copings were veneered with high impact polymer composite (HIPC) material (breCAM.HIPC, Bredent, Germany). The vertical marginal gap was captured under a magnification of 40X. Five equidistant marks on each surface of the die distinguished the points of measurement for a total of 20 readings per sample. The analysis was completed using an image analysis system (ImageJ 1.53t, National Institute of Health, USA). The specimens were loaded to failure at a crosshead speed of 1 mm/min and the load at failure was recorded to measure the fracture resistance.ResultsThe marginal gap was analyzed using one-way ANOVA followed by Tukey’s post hoc test. Fracture resistance was analyzed using Welch one-way ANOVA followed by the Games-Howell post hoc test. Marginal gap values showed a significant difference between the tested groups, with zirconia having significantly lower gap values (48.67 ± 11.98 µm) than both the PEEK CAD (108.00 ± 20.08 µm) and Press groups (108.00 ± 25.10 µm) (p < 0.001). However, the results of fracture resistance showed no significant difference (p = 0.06) with 1687.47 ± 253.29 N, 2156.82 ± 407.64 N, 2436.72 ± 725.93 N for zirconia, PEEK CAD, and Press, respectively. The significance level was p < 0.05.ConclusionsZirconia framework crowns have a smaller vertical marginal gap than milled and pressed PEEK crowns. Crowns fabricated from zirconia, PEEK CAD, or PEEK Press frameworks and veneered with composite resin have comparable fracture resistance lower than the maximum biting force in the posterior region.Clinical relevancePosterior crowns with zirconia frameworks are preferred over milled and pressed PEEK frameworks regarding margin adaptation, although all can safely survive the maximum occlusal forces without fracture.

Effect of analysis software program on measured deviations in complete arch, implant-supported framework scans

Implementation of fabrication trueness analysis by using a recently introduced nonmetrology-grade freeware program may help clinicians and dental laboratory technicians in their routine practice. However, knowledge of the performance of this freeware program when compared with the International Organization for Standardization recommended metrology-grade analysis software program is limited. The purpose of this in vitro study was to evaluate the effect of an analysis software program on measured deviations in the complete arch, implant-supported framework scans. A total of 20 complete arch, implant-supported frameworks were fabricated from a master standard tessellation language (STL) file from either polyetheretherketone (PEEK) or titanium (Ti) (n=10). All frameworks were then digitized by using different scanners to generate test STLs. All STL files were imported into a nonmetrology-grade freeware program (Medit Link) and a metrology-grade software program (Geomagic Control X) to measure the overall and marginal deviations of frameworks from the master STL file by using the root mean square (RMS) method. Data were analyzed by using the two 1-sided paired t test procedure, in which 50µm was considered as the minimal clinically meaningful difference (α=.05). When overall RMS values were considered, the nonmetrology-grade freeware program was not inferior to the metrology-grade software program (P<.05). When marginal RMS values were considered, the nonmetrology-grade freeware program was inferior to the metrology-grade software program only when PEEK frameworks were scanned with an E4 laboratory scanner (P>.05). The use of the tested nonmetrology-grade freeware program resulted in overall deviation measurements similar to those when a metrology-grade software program was used. The freeware program was inferior when marginal deviations were analyzed on E4 scans of a PEEK framework, which was the only scanner-material pair that led to a significant difference, among the 15 pairs tested.

A digital chairside repair protocol for removable partial dentures with polyetheretherketone frameworks

Polyetheretherketone (PEEK) has become popular for removable partial denture (RPD) frameworks but reports on their clinical follow-up and repair are lacking. Two defective PEEK-framework RPDs were repaired with computer-aided design and manufacturing technology, saving costs and time and simplifying the treatment process.

Finite Element Analysis of Endocrown and Post-and-Core Abutments for Removable Partial Dentures with Different Framework Materials.

To evaluate the stress distribution in endocrowns and post-and-core crowns used as abutments for a Kennedy Class I removable partial denture constructed with different framework materials. 3D models of a Kennedy Class I mandible were constructed. Cobalt-chromium (Co-Cr) and polyether ether ketone (PEEK) frameworks were simulated for Models 1 and 2, respectively. An endocrown and a fiber post-and-core crown for the mandibular left and right second premolar abutments, respectively, were simulated for both models. Lithium disilicate porcelain was defined for the crowns. A 200-N occlusal force was applied in the vertical and 30-degree oblique directions. The von Mises stresses were evaluated for the abutments and prostheses, and the principal stresses for the cortical bone under vertical and oblique loading. Endocrowns showed lower stress values than post-and-core crowns in both models. Post-and-core crowns generated the highest stress in Model 2 under vertical loading. The PEEK framework caused higher stress values on the abutments than Co-Cr. Compressive stresses were higher than tensile stresses in cortical bone. The highest compressive stress was observed around the left premolar cortical bone area in Model 1 under oblique loading. Oblique loading caused lower stress values than vertical loading, except for on the minor connectors and cortical bone. From a biomechanical perspective, endocrowns may be more advantageous than post-and-core crowns when used as abutments for a Kennedy Class I removable partial denture. In addition, Co-Cr frameworks showed more favorable stress distribution on abutments than PEEK frameworks. Int J Prosthodont 2023;36:203-215. doi: 10.11607/ijp.7269.

Polyetheretherketone computer-aided design and computer-aided manufacturing framework for All-on-Four mandibular full-arch prosthesis: 3 Years' retrospective study of peri-implant soft tissue changes and ridge base relationship.

This study was conducted to evaluate the clinical peri-implant soft tissue changes during the first year after occlusal loading and the ridge base relation after 3 years for mandibular computer-aided design and computer-aided manufacturing (CAD-CAM) screw-retained implant-supported hybrid prosthesis of polyetheretherketone (PEEK) framework utilized with All-on-Four treatment concept. Sixteen completely edentulous patients were rehabilitated by four implants following the All-on-Four protocol. After 3 months, the definitive prosthesis was constructed to be a screw-retained CAD-CAM milled framework from the modified PEEK (BioHPP), bonded to polymethylmethacrylate teeth and a pink shaded indirect light-polymerized nanofilled composite resin imitating the soft tissues. Peri-implant soft tissue changes regarding plaque, bleeding, gingival scores, and probing depth were evaluated at prosthesis insertion (T0), 6 months (T1), and 12 months (T2) after insertion. Also, monitoring of the ridge base relation was performed using cone beam computed tomography at time of insertion (T0), and 1 year (T1), 2 years (T2), and 3 years (T3) after mandibular fixed detachable All-on-Four framework insertion. Using Shapiro-Wilk tests using SPSS® software version 22 (SPSS Inc., Chicago, IL), all clinical data were nonparametric, while the ridge base relation data were parametric. There were statistically significant differences regarding a plaque, gingival, and bleeding scores for all implants with the advancement of time. However, there was a statistically insignificant difference regarding probing depth in the posterior implants (p = 0.581). Regarding ridge base relation, there was a significant difference between observation times only in the anterior ridge area in between the two anterior implants (p = 0.011). Within the limitations of the study, the full-arch PEEK framework of fixed-detachable, hybrid prosthesis used with the All-on-Four concept for rehabilitation of mandibular edentulous arches is an acceptable treatment approach. Based on the stable ridge base relation posteriorly found in this study, less stress is distributed to the underlining bone due to the shock-absorbing ability of PEEK. Special considerations for frequent soft tissue follow-up and regular maintenance of oral hygiene measures are recommended.

Effect of adhesive system, resin cement, heat-pressing technique, and thermomechanical aging on the adhesion between titanium base and a high-performance polymer

Statement of problemEven though polyetheretherketone (PEEK) has become popular for various prosthetic indications, a standard adhesive protocol to bond the PEEK to titanium bases has not been yet established. How the heat-pressing technique performs in this respect is also not clear. PurposeThe purpose of this in vitro study was to investigate the effect of an adhesive system-cement combination, the heat-pressing technique, and thermomechanical aging on the retention force between titanium bases and PEEK specimens. Material and MethodsSixty 9×11×20-mm PEEK specimens with a titanium base slot integrated into the design were milled to simulate an implant-supported PEEK framework for a cantilevered fixed prosthesis. The specimens were assigned to 8 groups (n=10) according to the titanium base primer (MKZ or Monobond) and resin cement (DTK or Multilink hybrid) used and with or without thermomechanical aging. Twenty PEEK specimens were directly heat-pressed on titanium bases, and half of the specimens were not subjected to thermomechanical aging (n=10). For nonaged groups, the PEEK specimen complex was tightened to an implant analog and secured on a custom-made pull-off device. Retention forces were measured by using the pull-off tensile test in a universal testing machine, and the maximum tensile bond strength (MPa) was calculated. The aged groups were subjected to 5000 cycles of thermal aging (5 °C to 55 °C), and the specimens were clamped to load the extension (cantilever) for 1 200 000 cycles with 120 N and 200 N at 1.5-Hz frequency. After aging, the pull-off test was performed for those specimens that survived thermomechanical aging. A nonparametric Kruskal-Wallis test was used to determine whether there was a difference among the groups, followed by pairwise Wilcoxon rank tests with Bonferroni correction. The Wilcoxon rank test was used to analyze the effect of thermomechanical aging in each adhesive system-cement or heat-press group (α=.05 for all tests). ResultsNone of the specimens failed during cyclic loading. According to the Kruskal-Wallis test, the effect of the PEEK-Ti base bonding technique on the retention force in the nonaged (P=.019) and thermomechanically aged groups was significant (P=.010). In the nonaged groups, the heat-pressing technique resulted in a higher retention force than when the specimens were bonded by using the Monobond-Multilink hybrid combination (P=.031). Thermomechanical aging did not significantly affect the results (P>.241). All failures were adhesive, with cement remaining only on the Ti-bases. ConclusionsAll bonding protocols tested resulted in a stable bond between PEEK and Ti-bases, as all specimens survived thermomechanical aging. The heat-pressing technique resulted in mean bond strength values similar to those obtained with the tested adhesive system-cement combinations with 1 exception; the nonaged heat-pressed groups presented higher bond strength than the Monobond-Multilink hybrid combination. Failure types indicated that the weaker bond was between the PEEK and the cements tested rather than between the titanium base and the cements, regardless of the adhesive system-cement combination.

COMPARISON OF MARGINAL ADAPTATION OF DIFFERENT FRAMEWORK MATERIALS BEFORE AND AFTER CEMENTATION: AN IN VITRO STUDY

Purpose: This study aimed to compare the marginal adaptation of different framework materials polyetheretherketone (PEEK), zirconia, and cobalt-chromium (Co-Cr) through direct metal laser sintered (DMLS) and conventional casting (CC) in fixed prosthetic restorations. Materials and Methods: A total of 80 stainless steel dies were embedded in silicone molds, and the master models obtained were divided into four groups (n=20): PEEK, zirconia, Co-Cr through DMLS and CC frameworks. The vertical marginal gap was measured by stereomicroscope at ×20 magnification. In addition to descriptive statistics in the evaluation of data, one-way ANOVA was used with the post hoc multiple comparison test Tamhane’s T2, as the data were normally distributed and variances differed according to the Kolmogorov–Smirnov and Shapiro–Wilk tests. Results: There was a statistically significant difference in vertical marginal gap before and after cementation in all groups (p&amp;lt;0.05). Conclusion: Before and after cementation, vertical marginal gap values of laser sintered Co-Cr, zirconia, and PEEK frameworks were clinically acceptable. Keywords: PEEK; Marginal Adaptation; Laser Sintered Co-Cr; Zirconia; Framework

Comparative evaluation of stress distribution of zirconia, cobalt chromium, and polyetheretherketone (PEEK) framework material on an atrophic maxilla in all-on-six implant treatment concepts: A three-dimensional finite element analysis

Aims: This study aims to evaluate the effect of prosthetic framework material on the stress distribution patterns of the all-on-six implant support system under vertical and oblique loading. Materials and methods: The cone beam computed tomography (CBCT) images of the maxilla were converted to a stereo lithography file. HyperMesh software system was accustomed to convert three-dimensional pictures into numerical models. Geometric models of short implant and zirconia, cobalt chromium, and polyetheretherketone (PEEK) framework material were created using SOLID EDGE software and were then inserted in the bone model. A total of six models were constructed with three different types of framework materials with four implants in the anterior maxilla region and two distal short implants and mini-abutments. The prosthetic frameworks were made with 14 teeth (central incisors to the second molar bilaterally). The models were transferred through the solid works simulation program for finite element analysis and stress distribution investigation. An oblique load of 150 N with 30 inclination in the linguo-buccal direction and vertical loads parallel to the long axis of the tooth with 100 N magnitude were applied unilaterally on the posterior teeth of each framework. Results: Principal and Von misses stress in the PEEK framework were least when compared to stresses in the zirconia and cobalt chromium framework on vertical loading and oblique loading. Conclusion: PEEK as a framework material had the least stress for the all-on-six implant treatment concepts on vertical and oblique forces than zirconia and cobalt chromium framework.

Effect of prosthetic design and restorative material on the stress distribution of implant-supported 3-unit fixed partial dentures: 3D-FEA

Objective: Evaluate the effect of Implant prosthetic designs and restorative material on the stress concentrationof 3-unit implant-supported restoration with two restorative materials. Material and Methods: Six differentscrew-retained prostheses models were virtually designed and divided according to design: fixed bridge (FB),cantilever bridge (CB), and separate crowns (SC). Then, each model was also divided into two subgroupsaccording to the material: Ultra-translucent multi-layered zirconia (Kuraray Noritake Dental Inc., Japan); or acombination of PEEK (Polyetheretherketone) framework (BioHPP, Bredent, GmbH &amp; Co., KG, Germany) andzirconia (ZR) crowns (ultra-translucent multi-layered zirconia, Kuraray Noritake Dental Inc., Japan). A verticalload of 100 N was applied statically perpendicular to the central fossa of each crown. The von-Mises stress wascomputed using Solidworks software (SolidWorks Corp, Massachusetts, USA), based on the physical parametersof the materials. Results: FB showed the lowest von Mises stress values out of all 3 design models. Moreover,the combination of PEEK and zirconia showed strain values smaller than full zirconia. The highest von Misesstress value was recorded in CB with the zirconia subgroup at (1098 MPa) while the lowest von Mises stressvalue was recorded in FB with combined PEEK and zirconia subgroup at (190 MPa). Conclusion: For three-unitimplant supported restorations, the use of PEEK framework and zirconia crowns was found to be more favorablebiomechanically regarding the prosthetic components, implant and bone stresses. KEYWORDSBiomechanics; Dental implants; Implant prosthetic designs; Finite element analysis; CAD/CAM.

Metal-Ceramic and Polyether Ether Ketone-Composite Maxillary Fixed Prosthesis Supported by Four Implants and Opposed by Removable Distal Extension Partial Dentures: A Comparative Study of Clinical and Prosthetic Outcomes.

This study aimed to evaluate clinical and prosthetic outcomes of metal-ceramic and polyether ether ketone (PEEK) fixed prostheses supported by four maxillary implants and opposed by distal extension removable partial dentures. Thirty participants with edentulous maxillary and distal extension mandibular ridges received four implants according to the All-on-4 treatment concept. The implants were immediately loaded by fixed acrylic prostheses. After 6 months, patients received either metal frameworks covered with porcelain teeth (metal group) or PEEK framework veneered with composite teeth (PEEK group). Plaque Index (PI), Gingival Index (GI), pocket depth (PD), implant stability quotient (ISQ), peri-implant marginal bone loss (MBL, using digital periapical radiographs), and implant survival were measured at baseline, 1 year, and 3 years. Prosthetic complications were measured on the patient and implant levels after 3 years. No implant failures occurred after insertion of the definitive prosthesis, and the implant survival rate was 100% in both groups. PI, GI, PD, ISQ, and MBL increased significantly with time. The most frequent complications were veneer fracture for the PEEK group and prosthetic screw loosening for the metal group. The metal group showed significantly higher PI, PD, and MBL than the PEEK group after 3 years. PEEK was associated with significantly higher veneer fracture than metal, while metal was associated with significantly higher prosthetic screw loosening than PEEK. Within the limitations of this study, the PEEK framework veneered with composite may be a suitable alternative to a metal porcelain prosthesis for All-on-4 implant rehabilitation in patients with maxillary edentulous arches opposed by distal extension mandibular ridges, as it was associated with favorable clinical and prosthetic outcomes after 3 years. However, it was associated with an increased rate of veneer or artificial gingiva fracture.

PEEK versus Metallic Attachment-Retained Obturators for Patient Satisfaction: A Randomized Controlled Trial.

Objective The aim of the study was patients’ satisfaction evaluation and radiographic evaluation of the terminal abutments of attachment-retained maxillary obturators with metal framework versus milled polyetheretherketone (PEEK) framework in the management of maxillectomy cases. Materials and Methods Eighteen participants were randomly divided into three parallel groups ( n = 6). Participants of the PEEK group received attachment-retained obturators with milled PEEK framework, the metal group received an attachment-retained obturator with a metallic framework, and the conventional group received conventional clasp-retained obturators with a metallic framework (Control group). The evaluation included was radiographic evaluation and patients’ satisfaction in this study included two scales—”The Obturator Functioning Scale” and “The European Organization for Research and Treatment of Cancer Head and Neck 35” using one-way ANOVA test. Results Both PEEK and metal groups showed a statistically significant lower mean bone loss ( p <0.050) compared with the conventional group during all follow-up periods. There is no statistically significant difference between the PEEK and metal groups during all follow-up periods. Regarding patient satisfaction, both the PEEK and metal groups showed a statistically significant decrease score ( p <0.050) compared with the conventional group in various aspects of patients’ satisfaction scales as satisfaction with the look and difficulty of talking to the public, and noticeable clasps. In comparison, the PEEK group showed a statistically significant decrease score ( p <0.050) than the metal group with respect to satisfaction with the look along all follow-up periods. Conclusions PEEK attachment-retained maxillary definitive obturators could be considered a promising treatment modality for patients with acquired maxillary defects with regard to esthetics and satisfaction.

Mechanical Response of PEKK and PEEK As Frameworks for Implant-Supported Full-Arch Fixed Dental Prosthesis: 3D Finite Element Analysis.

Objective Polymeric framework represent an innovative approach for implant-supported dental prostheses. However, the mechanical response of ultra-high performance polymers as frameworks for full-arch prostheses under the “all-on-four concept” remains unclear. The present study applied finite element analysis to examine the behavior of polyetherketoneketone (PEKK) and polyetheretherketone (PEEK) prosthetic frameworks. Materials and Methods A three-dimensional maxillary model received four axially positioned morse-taper implants, over which a polymeric bar was simulated. The full-arch prosthesis was created from a previously reported database model, and the imported geometries were divided into a mesh composed of nodes and tetrahedral elements in the analysis software. The materials were assumed as isotropic, elastic, and homogeneous, and all contacts were considered bonded. A normal load (500 N magnitude) was applied at the occlusal surface of the first left molar after the model was fixed at the base of the cortical bone. The microstrain and von-Mises stress were selected as criteria for analysis. Results Similarities in the mechanical response were observed in both framework for the peri-implant tissue, as well as for stress generated in the implants (263–264 MPa) and abutments (274–273 MPa). The prosthetic screw and prosthetic base concentrated more stress with PEEK (211 and 58 MPa, respectively) than with PEKK (192 and 49 MPa), while the prosthetic framework showed the opposite behavior (59 MPa for PEEK and 67 MPa for PEKK). Conclusion The main differences related to the mechanical behavior of PEKK and PEEK frameworks for full-arch prostheses under the “all-on-four concept” were reflected in the prosthetic screw and the acrylic base. The superior shock absorbance of PEKK resulted in a lower stress concentration on the prosthetic screw and prosthetic base. This would clinically represent a lower fracture risk on the acrylic base and screw loosening. Conversely, lower stress concentration was observed on PEEK frameworks.