Retention force of polyetheretherketone and cobalt-chrome-molybdenum removable dental prosthesis clasps after artificial aging.

OBJECTIVES: To examine the retention force of removable dental prosthesis (RDP) clasps made from polyetheretherketone (PEEK) and cobalt-chrome-molybdenum (CoCrMo, control group) after storage in water and artificial aging. MATERIALS AND METHODS: For each material, 15 Bonwill clasps with retentive buccal and reciprocal lingual arms situated between the second pre- and first molar were manufactured by milling (Dentokeep [PEEKmilled1], NT digital implant technology; breCAM BioHPP Blank [PEEKmilled2], bredent), pressing (BioHPP Granulat for 2 press [PEEKpressed], bredent), or casting (remanium GM 800+ [CoCrMo], Dentaurum); N = 60, n = 15/subgroup. A total of 50 retention force measurements were performed for each specimen per aging level (initial; after storage [30 days, 37 °C] and 10,000 thermal cycles; after storage [60 days, 37 °C] and 20,000 thermal cycles) in a pull-off test. Data were statistically analyzed using one-way ANOVA, post hoc Scheffé and mixed models (p < 0.05). RESULTS: Initial, PEEKpressed (80.2 ± 35.2) and PEEKmilled1 (98.9 ± 40.3) presented the lowest results, while PEEKmilled2 (170.2 ± 51.8) showed the highest values. After artificial aging, the highest retention force was observed for the control group (131.4 ± 56.8). The influence of artificial aging was significantly higher for PEEK-based materials. While PEEKmilled2 and PEEKpressed showed an initial decline in retention force, all other groups presented no impact or an increase in retention force over a repetitive insertion and removal of the clasps. CONCLUSIONS: Within the tested PEEK materials, PEEKmilled2 presented superior results than PEEKpressed. Although CoCrMo showed higher values after artificial aging, all materials exhibited sufficient retention to recommend usage under clinical conditions. CLINICAL RELEVANCE: As RDPs are still employed for a wide range of indications, esthetic alternatives to conventional CoCrMo clasps are sought.

Evolution of lung and kidney allograft function in patients receiving kidney after lung transplantation.

Calcineurin inhibitor (CNI) toxicity leads to end-stage renal disease in almost half of long-term survivors after lung transplantation, some of them receiving kidney transplants. Little is known about the outcomes of kidney and lung allograft function following kidney after lung transplantation (KALTPL) in the modern era. We retrospectively analyzed a group of 13 consecutive patients who received a KALTPL with respect to their renal and pulmonary function and immunological evolution over 2 years. We documented a stable evolution of forced expiratory volume in 1 second (FEV1) after KALTPL in most patients as well as an excellent kidney graft during the 2-year follow-up period. In our small cohort, living donations showed a significantly higher estimated glomerular filtration rate compared to deceased donation (75.7 compared to 41.6 mL/min). Patients who received a preemptive KALTPL were more likely to improve their lung function after KALTPL. Four patients developed de novo donor-specific antibodies (DSA) against the kidney graft. There were no DSA against shared antigens from the lung allograft. De novo DSA did not lead to graft loss in any patient. All 13 patients survived the first 24 months after KALTPL.