Fausto Zamparini

Polylactic acid-based porous scaffolds doped with calcium silicate and dicalcium phosphate dihydrate designed for biomedical application

Polylactic acid (PLA), dicalcium phosphate dihydrate (DCPD) and/or hydraulic calcium silicate (CaSi) have been used to prepare highly-porous scaffolds by thermally induced phase separation technique (TIPS). Three experimental mineral-doped formulations were prepared (PLA-10CaSi, PLA-5CaSi-5DCPD, PLA-10CaSi-10DCPD). Pure PLA scaffolds constituted the control group. Scaffolds were tested for their chemical-physical and biological properties, namely calcium release, alkalinizing activity, surface microchemistry and micromorphology by ESEM, apatite-forming ability by EDX, micro-Raman and IR spectroscopy, thermal properties by differential scanning calorimetry, mechanical properties by quasi-static parallel-plates compression testing, porosity by a standard water-absorption method and direct-contact cytotoxicity. All mineral-doped scaffolds released biologically relevant ions (biointeractive). A B-type carbonated apatite layer (thickness decreasing along the series PLA-10CaSi-10DCPD>PLA-10CaSi>PLA-5CaSi-5DCPD>PLA) was detected on the surface of all the 28d-aged scaffolds. Surface pores of fresh scaffolds ranged from 10 to 20μm in pure PLA to 10-100μm in PLA-10CaSi. An increase in porosity was detected in 28d-aged pure PLA scaffolds (approx. 30% of material loss with decrease of the PLA chain length); differently, in mineral-doped scaffolds, the PLA degradation was balanced by deposition/nucleation of apatite. All scaffolds showed absence of toxicity, in particular PLA-10CaSi-10DCPD. The designed scaffolds are biointeractive (release biologically relevant ions), nucleate apatite, possess high surface and internal open porosity and can be colonized by cells, appearing interesting materials for bone regeneration.

A 3-Year Prospective Cohort Study on 132 Calcium Phosphate-Blasted Implants: Flap vs Flapless Technique.

PURPOSE To evaluate the survival rate and marginal bone loss (MBL) of a calcium phosphate-blasted titanium implant inserted by a flap or flapless technique and to study the morphochemical characteristics of the implant surface. MATERIALS AND METHODS Sixty out of 85 patients who received one or more implants were selected as eligible for this prospective longitudinal cohort clinical study. Titanium implants (n = 132) were placed in human healthy subjects using either a flap or flapless technique, selected on the basis of the best practice. The survival rate and MBL were evaluated after 3 months (preloading stress-free healing period) and after 6, 12, 24, and 36 months in relation to implant diameter, location, sex, and smoking habits. Surface morphochemical analyses were performed by environmental scanning electron microscopy connected with energy-dispersive x-ray (ESEM/EDX). RESULTS The overall survival rate was 97.72%. After 3 and 36 months, MBL was 0.36 ± 0.66 mm and 1.09 ± 1.10 mm for the flapless group and 0.29 ± 0.51 mm and 1.03 ± 0.92 mm for the flap group. MBL showed a statistically significant increase with time (P = .0001), and differences were found at all times since 6 months. No statistical differences between the flapless and flap groups and sex were observed at any time, while MBL was significantly higher in the maxillary versus mandibular location (6, 12, and 24 months) and in smokers versus nonsmokers (6 months). Higher MBL in both groups was found for a smaller diameter (3.5 mm) than larger diameter (4.1, 5 mm). The surface showed a Ti-Al-V alloy displaying a uniform nanotexture. CONCLUSION The implant system showed a high survival rate and markedly lower MBL considering the limits for acceptable progression. Flapless and flap techniques demonstrated similar results of MBL at the preloading healing period and at the 6 months to 3 years postloading periods. Both surgical procedures induced an early MBL during the preloading stress-free period. Implant diameter, mandibular/maxillary location, preloading stress-free period, and smoking habits affect MBL more than the type of surgery after both short- and long-term follow-up.

Immediate Early and Delayed Implants: A 2-Year Prospective Cohort Study of 131 Transmucosal Flapless Implants Placed in Sites With Different Pre-extractive Endodontic Infections

Introduction: To evaluate clinical outcome of early, immediate, and delayed transmucosal implants placed in patients affected by acute/chronic endodontic lesions. Materials and Methods: Eighty-five consecutive patients received 131 titanium implants with zirconium-oxide blasted surface. Pre-extractive diagnosis represented the main criteria for implant placement timing, following “best treatment” criteria. Implants were placed with flapless transmucosal technique. Hopeless teeth with chronic periapical lesions received atraumatic extraction, and an implant was immediately placed (Immediate Group, n = 29). Teeth with acute periapical lesion/abscess were extracted and implants placed after 8 to 12 weeks (Early Group, n = 29). Implants placed 10- to 12-month after extraction constituted the control group (delayed group, n = 73). Implants were loaded 3 months after insertion with provisional resin crowns and after approximately 15 days with definitive ceramic crowns. Marginal bone loss (MBL) was measured in a single-blind manner on periapical radiographs at 1, 3, 6, 12, and 24 months. Results: Multilevel analysis described exploring factors associated with MBL. Survival rate was 100%. MBL after 24 months was 0.78 ± 0.70 (95% confidence interval [CI]: 0.20 to −1.37) at immediate, 0.48 ± 0.70 at early (95% CI: −0.006 to −0.961), and 1.02 ± 1.01 (95% CI: 0.61 to −1.43) at delayed groups. Implant groups (immediate/early/delayed) and location (maxillary/mandibular) showed statistically significant results. Early group showed the lowest MBL values. The immediate group demonstrated less MBL than the delayed group. Conclusion: Early implant placement technique preserves periimplant marginal bone level more than immediate and delayed techniques.