Primary stability and PES/WES evaluation for immediate implants in the aesthetic zone: a pilot clinical double-blind randomized study

The use of immediate implants in the aesthetic area is a technique widely used in modern implantology. The characteristics of the patient, the implant, and the surgical procedure used may influence the final results. The aim was to assess whether the implant design affects primary (P.S.) and secondary stability (S.S.), bone level (B.L.), and PES/WES evaluation. Twenty implants with two different designs (n = 10) were immediately placed and randomly located in the upper anterior maxilla with no grafting material. Implant-Stability-Quotient (ISQ), B.L., and Pink-Esthetic-Score/White-Esthetic-Score (PES/WES) were evaluated. Shapiro–Wilk normality test was performed to determine the sample normality, as the data did not follow a normal distribution, the Wilcoxon-Mann–Whitney test was applied (p < 0.05). ISQ was determined at placement (PS): control 59.1 (C.I.54.8–63.3); experimental 62.2(C.I.60.1–64.2) and three months after placement (SS): control 62.2.1 (C.I.53.3–71.0); experimental 67.2(C.I.65.8–68.5). The BL was measured at three months after placement: control 0.38 mm (C.I.− 0.06 to + 0.83); experimental 0.76 mm (C.I.0.33–1.19) and at 12 months post-loading: control 0.07 mm (C.I.− 0.50–0.65); experimental 0.90 mm (C.I.0.38–1.42). PES/WES values were evaluated for the control group: 15 (C.I.12.68–17.32), and for the experimental group 15.20 (C.I.11.99–18.41). No significant differences were shown between both implant designs. A good grade of osseointegration and primary/secondary stability was achieved, as well as proper maintenance of crestal bone and adequate PES/WES scores. The criteria for selection for the ideal patient for immediate implant placement is essential.ClinicalTrials Protocol ID: NCT04343833.

Unstable regulatory T cells, enriched for naïve and Nrp1neg cells, are purged after fate challenge

Regulatory T cells (Tregs) are indispensable for the control of immune homeostasis and have clinical potential as a cell therapy for treating autoimmunity. Tregs can lose expression of the lineage-defining Foxp3 transcription factor and acquire effector T cell (Teff) characteristics, a process referred to as Treg plasticity. The extent and reversibility of such plasticity during immune responses remain unknown. Here, using a murine genetic fate-mapping system, we show that Treg stability is maintained even during exposure to a complex microbial/antigenic environment. Furthermore, we demonstrate that the observed plasticity of Tregs after adoptive transfer into a lymphopenic environment is a property limited to only a subset of the Treg population, with the nonconverting majority of Tregs being resistant to plasticity upon secondary stability challenge. The unstable Treg fraction is a complex mixture of phenotypically distinct Tregs, enriched for naïve and neuropilin-1–negative Tregs, and includes peripherally induced Tregs and recent thymic emigrant Tregs. These results suggest that a “purging” process can be used to purify stable Tregs that are capable of robust fate retention, with potential implications for improving cell transfer therapy.

Comparison of Implant Stability between Regenerated and Non-Regenerated Bone. A Prospective Cohort Study

Implant stability is one of the main indicators of successful osseointegration. Although it has been measured in numerous studies, there has been little research on implant stability in regenerated bone. The study compares primary and secondary stability between implants placed in regenerated versus native bone and evaluates the influence of bone quality on the results. Sixty implants were placed in 31 patients: 30 implants inserted in native bone (non-regenerated) after a healing period of at least 6 months post-exodontia and 30 inserted in regenerated bone at 6 months after grafting with xenograft. Resonance frequency analysis (RFA) was used to obtain implant stability quotient (ISQ) values at baseline (implant placement), 8 weeks, and 12 weeks. Statistically significant differences were found between implants placed in regenerated bone and those placed in native bone at all measurement time points (p < 0.05). ISQ values were significantly influenced by bone quality at baseline (p < 0.05) but not at 8 or 12 weeks. Greater stability was obtained in implants placed in native bone; however, those placed in regenerated bone showed adequate primary and secondary stability for prosthetic loading. Bone quality influences the primary but not secondary stability of the implants in both native and regenerated bone.

Relation Between Insertion Torque and Implant Stability Quotient: A Clinical Study

Objectives This study aimed to assess the relation between the insertion torque and implant stability quotient (ISQ recorded immediately and 6 months after implant placement). Materials and Methods Twenty-five patients over the age of 18 years were selected for this study. One implant was placed per patient after tooth extraction. The implant site needed 15 mm in height and 8 mm in width. All implants had the same size (11.5 × 3.75 mm) and brand (Hexagonal Morse cone, DSP Biomedical). The insertion torque (Ncm) and resonance frequency analysis (ISQ value) (Osstell Mentor) were used to assess the primary stability (on the day of surgery). After 6 months, ISQ value was used to assess the secondary stability of each implant. Statistical Analysis The insertion torque data were correlated with ISQ measurements by using Pearson’s correlation. The significance level was 5%. Results There was a positive correlation between insertion torque and initial ISQ (correlation: 0.457; p = 0.022); however, no correlation was found between insertion torque and final ISQ (p = 0.308). Conclusion The present study demonstrated that there is a positive correlation between the insertion torque and the initial ISQ. Therefore, the higher the insertion torque, the higher the initial ISQ (or vice versa).

Correlation between Primary, Secondary Stability, Bone Density, Percentage of Vital Bone Formation and Implant Size

Background: This study aims to evaluate whether there is a correlation between implant stability, bone density, vital bone formation and implant diameter and length. Methods: Ninety patients were enrolled in this study. They underwent a socket preservation procedure with allograft or PRF and after 4 months, a total of 90 implants were placed. CBCT scans were assigned prior to implant placement in order to assess the bone density. During the surgical re-entry, a bone biopsy was harvested with a trephine drill. Immediately after implant insertion, the primary stability was measured. The secondary stability was measured 4 months after implant placement. Results: Primary stability showed a significant positive linear correlation with bone density (r = 0.471, p < 0.001) as well as with percentage of new bone formation (r = 0.567, p < 0.001). An average significant association of secondary stability with bone density (rs = 0.498, p < 0.001) and percentage of newly formed bone (r = 0.477, p < 0.001) was revealed. The mean values of primary stability in all three implant sizes, regarding the diameter of the implants, were similar (narrow 67.75; standard 66.78; wide 71.21) with no significant difference (p = 0.262). The same tendency was observed for secondary stability (narrow 73.83; standard 75.25; wide 74.93), with no significant difference (p = 0.277). Conclusions: The study revealed a high correlation between primary and secondary implant stability, and bone density, as well as with the percentage of vital bone formation. Implant length and diameter revealed no linear correlation with the implant stability.