Polyetheretherketone CAD-CAM framework for all-on-4 mandibular full arch prosthesis: Three years' retrospective study of periimplant soft tissue changes and ridge base relationship

Efficacy of laser biostimulation for mandibular narrow ridges treated with one-stage ridge splitting and two-implant overdentures: A one-year preliminary study

STATEMENT OF PROBLEM

The management of patients with narrow-mandibular ridges who seek prosthetic rehabilitation is challenging.

PURPOSE

The purpose of this one-year preliminary clinical study was to compare the effects of laser biostimulation and a placebo on peri-implant tissues for a 2-implant-retained mandibular polyetheretherketone (PEEK) overdenture on expanded narrow mandibular ridges.

MATERIAL AND METHODS

Eighteen completely edentulous participants were enrolled for mandibular ridge splitting in the canine regions, followed by expansion, the placement of implants, and the application of a bone graft. In the test group, laser therapy was applied labially and lingually at the surgical sites, while a placebo laser was used in the control group. PEEK overdentures retained by LOCATOR attachments were provided after 6 months. Clinical evaluations were performed using probing depth, plaque, bleeding, and gingival indices at insertion and 3, 6, and 12 months after insertion. Vertical bone loss (VBL) was evaluated with periapical radiograph at insertion and 6 and 12 months later. The Mann-Whitney test was used to test the difference between the 2 different groups at each evaluation time (α=.05). The Friedman-test was used, followed by Wilcoxon signed rank test, to test the change over time in the same group, and the Bonferroni adjusted significance level was used for multiple comparisons.

RESULTS

Some clinical and radiographic parameters significantly increased with time in both groups (P<.001). Significant differences between the 2 groups were revealed in bleeding scores at 3 months (P=.006) and 6 months (P=.018). Also, significant differences between the 2 groups were observed in gingival scores at 3 months (P=.002), 6 months (P=.015), and 12 months (P=.019) after overdenture insertion in favor of the laser group. Peri-implant VBL was significantly higher in the non-laser group at 6 months (P=.015), and 12 months (P=.001).

CONCLUSIONS

Within the limitations of this clinical study, respecting the small sample size and the short follow-up period, laser bio-stimulation after 1-stage ridge splitting in narrow mandibular ridges enhanced the soft and hard peri implant tissues when used with LOCATOR attachments and PEEK overdentures.

Effect of different implant positions for two implant-retained mandibular overdenture: a retrospective 5-years radiographic evaluation of the circumferential peri-implant bone loss and posterior ridge resorptive changes

BACKGROUND

Studies did not recommend which position for implant overdenture poses the lowest biomechanical risk and the least chance of peri-implant bone loss and ridge resorption for those who might need a mandibular two-implant overdenture. The study objectives were to investigate the impact of implant position, in lateral incisors or canine positions, on peri-implant bone loss and posterior ridge resorption.

METHODS

Fifty patients with mandibular two-implants were recalled and divided according to the implant position into two groups (group L: implants in lateral incisor positions and group C: implants in canine positions). The circumferential peri-implant bone level and posterior ridge resorption were assessed at implant insertion (T0), one year later (T1), and five years later (T5) using the follow-up CBCT. Data were analyzed using the Statistical Package of Social Science (SPSS) program. A Mann-Whitney test was used to compare two different groups. Paired groups were compared using the Wilcoxon signed-rank test. The threshold of significance is fixed at a 5% level (p-value).

RESULTS

Significant differences in the vertical bone loss between groups appeared at (T5 - T1) (Mann Whitney test, (P = 0.01)) and at (T5 - T0) (Mann Whitney test, (P = 0.005)), and a significant difference in horizontal bone loss between groups was found at (T1 - T0) (Mann Whitney test, (P = 0.041)) and (T5 - T1) (Mann Whitney test, (P = 0.041)). Also, there were significant differences over the evaluation period between groups at certain points along the ridge at M1 (Mann Whitney test, (P = 0.021)), M3 (Mann Whitney test, (P = 0.008)), and M4 (Mann Whitney test, (P = 0.015)).

CONCLUSIONS

According to the findings of this clinical study, the placement of implants in the lateral incisor position for two implant-retained overdentures is a viable choice. In comparison to the canine position, the lateral incisor position demonstrated superior peri-implant responses, which could potentially enhance the longevity of the implants. Furthermore, the placement of implants in the lateral incisor position can promote a more even distribution of stress and help mitigate posterior ridge resorption. Conversely, implants in the canine position may cause a seesaw effect and result in greater posterior ridge resorption.

CLINICAL TRIAL REGISTRY NUMBER

(NCT06055842) (13/03/2024).

Mandibular biomechanics rehabilitated with different prosthetic restorations under normal and impact loading scenarios

BACKGROUND

Restorative treatment options for edentulous patients range from traditional dentures to fixed restorations. The proper selection of materials greatly influences the longevity and stability of fixed restorations. Most prosthetic parts are frequently fabricated from titanium. Ceramics (e.g. zirconia) and polymers (e.g. PEEK and BIOHPP) have recently been included in these fabrications. The mandibular movement produces complex patterns of stress and strain. Mandibular fractures may result from these stresses and strains exceeding the critical limits because of the impact force from falls or accidents. Therefore, it is necessary to evaluate the biomechanical behavior of the edentulous mandible with different restorations under different loading situations.

OBJECTIVE

This study analyzes the biomechanical behavior of mandibles after four prosthetic restorations for rehabilitation under normal and impact loading scenarios.

MATERIAL AND METHODS

The mandibular model was constructed with a fixed restoration, which was simulated using various materials (e.g. Titanium, Zirconia & BIOHPP), under frontal bite force, maximum intercuspation, and chin impact force. From the extraction of tensile and compressive stresses and strains, as well as the total deformation of mandible segments, the biomechanical behavior and clinical situations were studied.

RESULTS

Under frontal bite, the anterior body exhibited the highest tensile (60.34 MPa) and compressive (108.81 MPa) stresses using restoration 4, while the condyles and angles had the lowest tensile (7.12 MPa) and compressive (12.67 MPa) stresses using restoration 3. Under maximum intercuspation, the highest tensile (40.02 MPa) and compressive (98.87 MPa) stresses were generated on the anterior body of the cortical bone using restoration 4. Additionally, the lowest tensile (7.7 MPa) and compressive (10.08 MPa) stresses were generated on the condyles and angles, respectively, using restoration 3. Under chin impact, the highest tensile (374.57 MPa) and compressive (387.3 MPa) stresses were generated on the anterior body using restoration 4. Additionally, the lowest tensile (0.65 MPa) and compressive (0.57 MPa) stresses were generated on the coronoid processes using restoration 3. For all loading scenarios, the anterior body of the mandible had the highest stress and strain values compared with the other segments. Compared to the traditional titanium restoration.2, restoration.1(zirconia) increases the tensile and compressive stresses and strains on the mandibular segments, in contrast to restoration.3 (BIOHPP). In addition, zirconia implants exhibited higher displacements than the other implants.

CONCLUSION

In the normal loading scenario, the tensile and compressive stresses and strains on the mandible were within the allowable limits when all restorations were used. Under the chin impact loading scenario, the anterior body of the mandible was damaged by restorations 1 and 4.

Five years of radiographic evaluation for the peri-implant bone changes of all-on-four implant prostheses constructed from different framework materials using different digital construction techniques

BACKGROUND

There is insufficient evidence recommending a framework material and a CAD/CAM manufacturing technique for mandibular implant-supported prostheses. The study objective was to evaluate the clinical application of different materials and construction techniques used for mandibular All-on-4 prosthesis on circumferential peri-implant bony changes after 5 years.

METHODS

Thirty-six male patients with all-on-4 mandibular implant-supported prostheses were recalled and divided into three groups. Group PK (patients with frameworks milled from PEEK blocks), Group PSM (patients with frameworks milled from soft metal blocks), and Group SLM (patients with frameworks constructed with additive manufacturing; selective laser melting). The circumferential bone level on all implant faces was assessed with a CBCT. Two-way repeated measures ANOVA was used to compare vertical bone loss (VBL) and horizontal bone loss (HBL) between different groups, implant positions, and observation times followed by Tukey's multiple comparisons.

RESULTS

For all observation times, there was a significant difference in VBL between groups for both anterior and posterior implants (P < .001). For anterior implants, group PSM showed the lowest VBL while group PK showed the highest for anterior and posterior implants. For all groups, HBL significantly increased after 5 years for both anterior and posterior implants (P < .001). For anterior implants, group PSM showed the highest HBL. For posterior implants, group PK and SLM showed the highest.

CONCLUSION

Within the study's limitations, mandibular implant-supported fixed frameworks fabricated with either milling from PEEK or soft metal blocks, or additive manufacturing (laser melting technology) exhibited significant vertical and horizontal bone height changes after 5 years.

CLINICAL TRIAL REGISTRY NUMBER

(NCT06071689) (11/10/2023).

Clinical Outcomes of CAD-CAM Subperiosteal Implants for the Rehabilitation of Atrophic Jaws

Thanks to the use of new digital technologies and innovations in materials, there has been an increasing interest in subperiosteal implants. These implants are considered to be helpful for the rehabilitation of severe jaw atrophies, as they overcome some disadvantages of endosseous implantology. In the present clinical retrospective study, 18 patients were treated and the clinical outcomes of the treatment were recorded after 12 months of follow-up.

Comparative Analysis of the Mechanical Properties and Biocompatibility between CAD/CAM and Conventional Polymers Applied in Prosthetic Dentistry

Modern media often portray CAD/CAM technology as widely utilized in the fabrication of dental prosthetics. This study presents a comparative analysis of the mechanical properties and biocompatibility of CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) polymers and conventional polymers commonly utilized in prosthetic dentistry. With the increasing adoption of CAD/CAM technology in dental laboratories and practices, understanding the differences in material properties is crucial for informed decision-making in prosthodontic treatment planning. Through a narrative review of the literature and empirical data, this study evaluates the mechanical strength, durability, esthetics, and biocompatibility of CAD/CAM polymers in comparison to traditional polymers. Furthermore, it examines the implications of these findings on the clinical outcomes and long-term success of prosthetic restorations. The results provide valuable insights into the advantages and limitations of CAD/CAM polymers, informing clinicians and researchers about their suitability for various dental prosthetic applications. This study underscores the considerable advantages of CAD/CAM polymers over conventional ones in terms of mechanical properties, biocompatibility, and esthetics for prosthetic dentistry. CAD/CAM technology offers improved mechanical strength and durability, potentially enhancing the long-term performance of dental prosthetics, while the biocompatibility of these polymers makes them suitable for a broad patient demographic, reducing the risk of adverse reactions. The practical implications of these findings for dental technicians and dentists are significant, as understanding these material differences enables tailored treatment planning to meet individual patient needs and preferences. Integration of CAD/CAM technology into dental practices can lead to more predictable outcomes and heightened patient satisfaction with prosthetic restorations.

Flexural strength, surface roughness, and biofilm formation of ceramic-reinforced PEEK: An in vitro comparative study

PURPOSE

This in vitro study aimed to compare flexural strength, surface roughness, and biofilm formation of ceramic-reinforced polyetheretherketone (PEEK) with conventionally heat-compressed and milled polymethylmethacrylate (PMMA) denture base materials.

MATERIALS AND METHODS

Thirty strips (6.4 mm × 10 mm × 3 mm) and 30 discs (10 mm × 1 mm) were fabricated from a heat-compressed PMMA, milled PMMA, and ceramic-reinforced PEEK, 10 each. One surface of each sample was polished to mimic the laboratory procedure for denture base materials. Strips were then subjected to a three-point bend test using a universal testing machine at a crosshead speed of 5.0 mm/min. An optical profilometer was used to assess the Ra value (mm) of the discs on polished and unpolished sides. Biofilm formation behavior was analyzed by measuring the colony-forming unit (CFU)/mL of Candida albicans on the unpolished surface of the discs. One-way ANOVA followed by Tukey multiple comparison tests were used to compare the flexural strength, Ra value, and biofilm formation of the studied materials (a = 0.05).

RESULTS

Ceramic-reinforced PEEK showed significantly higher flexural strength (178.2 ± 3.2 MPa) than milled PMMA (89.6 ± 0.8 MPa; p < 0.001) and heat-compressed PMMA (67.3 ± 5.3 MPa; p < 0.001). Ceramic-reinforced PEEK exhibited a significantly higher Ra value than the other groups on unpolished sides; however, the polishing process significantly reduced the Ra values of all studied groups (p < 0.05). There was no significant difference in C. albicans adhesion among the groups (p < 0.05).

CONCLUSION

The flexural strength of tested materials was within acceptable limits for clinical use as a denture base material. Ceramic-reinforced PEEK had the highest surface roughness; however, its similarity in biofilm formation to other groups indicates its clinical acceptability as denture base material.

Complete-arch implant-supported fixed dental prostheses fabricated with PEEK and PEKK framework: a systematic review

PURPOSE

To evaluate the performance of complete-arch implant-supported fixed dental prostheses (FDPs) fabricated with polyetheretherketone (PEEK) and polyetherketoneketone (PEKK) framework in clinical cases.

MATERIALS AND METHODS

This systematic review followed the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses and was registered in the International Prospective Register of Systematic Reviews with the number CRD42023399494. The electronic database PubMed, Cochrane Library and EBSCOhost were assessed for clinical research and reports on complete-arch implant-supported FDPs fabricated with PEEK and PEKK framework. Human studies with a minimum follow-up of 1 year and published in an English language were the only ones included.

RESULTS

The initial database and hand search provided 564 articles. Finally, 12 articles published between 2018 and 2022 were included in this systematic review. The mean follow-up ranged from 1 year to 6 years. The included studies reported 119 (114 PEEK, 5 PEKK) complete-arch implant-supported FDPs during 1 year follow-up. The cumulative survival rate of prostheses with PEEK as a framework was 97.3%. Prostheses fractures and complications were found with both PEEK and PEKK frameworks. No implant failure reported with both PEEK and PEKK prostheses.

CONCLUSION

In short-term follow-up, the complete-arch implant-supported FDPs with PEEK as a framework showed a good survival rate and acceptable health of the supporting tissues. The PEEK framework had shown adhesion issues as the most common prosthetic complication. Limited data were available on PEKK as framework material, so further long-term clinical trials are required.

The All-on-4 Concept Using Polyetheretherketone (PEEK)-Acrylic Resin Prostheses: Follow-Up Results of the Development Group at 5 Years and the Routine Group at One Year

BACKGROUND

It is necessary to investigate the application of polymer materials in implant dentistry. The aim of this study was to examine the outcome of full-arch polyetheretherketone (PEEK)-acrylic resin implant-supported prostheses.

METHODS

Seventy-six patients were rehabilitated consecutively with 100 full-arch implant-supported prostheses of PEEK-acrylic resin (a development group (DG): 37 patients with 5 years of follow-up; a routine group (RG): 39 patients with 1 year of follow-up). The primary outcome measure was prosthetic survival. Secondary outcome measures were implant survival, marginal bone loss, biological complications, prosthetic complications, veneer adhesion, plaque levels, bleeding levels, and a patient subjective evaluation (including the Oral Health Impact Profile for the RG).

RESULTS

In both groups, prosthetic (DG: 93.6%; RG: 100%) and implant survival (DG: 98.9%; RG: 99.5%) were high, and marginal bone loss was low (DG: 0.54 mm; RG: 0.28 mm). The veneer adhesion rate was 28.6% of prostheses in DG (RG = 0%). Mechanical complications occurred in 49% and 11.8% of prostheses in DG and RG, respectively. Biological complications, plaque, and bleeding levels were low in both groups. The subjective patient evaluation was excellent in both groups (8.6 < DG < 8.8; 9.3 < RG < 9.5; OHIP = 1.38).

CONCLUSIONS

Within the limitations of this study, PEEK can be considered a viable prosthetic alternative.