The influence of truncated-conical implant length on primary stability in maxillary and mandibular regions: an in vitro study using polyurethane blocks.

OBJECTIVES: This in vitro study is aimed at assessing whether implant primary stability is influenced by implant length in artificial bone with varying densities. MATERIALS AND METHODS: A total of 120 truncated-conical implants (60 long-length: 3p L, 3.8 × 14 mm; 60 short-length: 3p S, 3.8 × 8 mm) were inserted into 20, 30, and 40 pounds per cubic foot (PCF) density polyurethane blocks. The insertion torque (IT), removal torque (RT), and resonance frequency analysis (RFA) values were recorded for each experimental condition. RESULTS: In 30 and 40 PCF blocks, 3p S implants exhibited significantly higher IT values (90 and 80 Ncm, respectively) than 3p L (85 and 50 Ncm, respectively). Similarly, RT was significantly higher for 3p S implants in 30 and 40 PCF blocks (57 and 90 Ncm, respectively). However, there were no significant differences in RFA values, except for the 20 PCF block, where 3pS implants showed significantly lower values (63 ISQ) than 3p L implants (67 ISQ) in both the distal and mesial directions. CONCLUSIONS: These results demonstrated that the implant's length mainly influences the IT and RT values in the polyurethane blocks that mimic the mandibular region of the bone, resulting in higher values for the 3p S implants, while the RFA values remained unaffected. However, in the lowest density block simulating the maxillary bone, 3p L implants exhibited significantly higher ISQ values. CLINICAL RELEVANCE: Therefore, our data offer valuable insights into the biomechanical behavior of these implants, which could be clinically beneficial for enhancing surgical planning.

Finite Element Analysis (FEA) of a Premaxillary Device: A New Type of Subperiosteal Implant to Treat Severe Atrophy of the Maxilla.

Extreme atrophy of the maxilla still poses challenges for clinicians. Some of the techniques used to address this issue can be complex, risky, expensive, and time consuming, often requiring skilled surgeons. While many commonly used techniques have achieved very high success rates, complications may arise in certain cases. In this context, the premaxillary device (PD) technique offers a simpler approach to reconstruct severely atrophic maxillae, aiming to avoid more complicated and risky surgical procedures. Finite element analysis (FEA) enables the evaluation of different aspects of dental implant biomechanics. Our results demonstrated that using a PD allows for an optimal distribution of stresses on the basal bone, avoiding tension peaks that can lead to bone resorption or implant failure. ANSYS® was used to perform localized finite element analysis (FEA), enabling a more precise examination of the peri-crestal area and the PD through an accurate mesh element reconstruction, which facilitated the mathematical solution of FEA. The most favorable biomechanical behavior was observed for materials such as titanium alloys, which helped to reduce stress levels on bone, implants, screws, and abutments. Additionally, stress values remained within the limits of basal bone and titanium alloy strengths. In conclusion, from a biomechanical point of view, PDs appear to be viable alternatives for rehabilitating severe atrophic maxillae.

Complex Electromagnetic Fields Reduce Candida albicans Planktonic Growth and Its Adhesion to Titanium Surfaces.

This study evaluates the effects of different programs of complex electromagnetic fields (C.M.F.s) on Candida albicans, in planktonic and sessile phase and on human gingival fibroblasts (HGF cells). In vitro cultures of C. albicans ATCC 10231 and HGF cells were exposed to different cycles of C.M.F.s defined as: oxidative stress, oxidative stress/antibacterial, antibacterial, antibacterial/oxidative stress. Colony forming units (CFUs), metabolic activity, cells viability (live/dead), cell morphology, filamentation analysis, and cytotoxicity assay were performed. The broth cultures, exposed to the different C.M.F.s, were grown on titanium discs for 48 h. The quantity comparisons of adhered C. albicans on surfaces were determined by CFUs and scanning electron microscopy. The C. albicans growth could be readily controlled with C.M.F.s reducing the number of cultivable planktonic cells vs. controls, independently by the treatment applied. In particular, the antibacterial program was associated with lower levels of CFUs. The quantification of the metabolic activity was significantly lower by using the oxidative stress program. Live/dead images showed that C.M.F.s significantly decreased the viability of C. albicans. C.M.F.s inhibited C. albicans virulence traits reducing hyphal morphogenesis, adhesion, and biofilm formation on titanium discs. The MTS assay showed no negative effects on the viability of HGF. Independent of the adopted protocol, C.M.F.s exert antifungal and anti-virulence action against C. albicans, no cytotoxicity effects on HGF and can be useful in the prevention and treatment of yeast biofilm infections.