Francesco Azzola | Università degli Studi di Milano - State University of Milan (Italy) (original) (raw)

Papers by Francesco Azzola

A, B, C, and D, show 3D reconstructions of machined, grit-blasted, laser-treated and ena... more A, B, C, and D, show 3D reconstructions of machined, grit-blasted, laser-treated and enamel surfaces. E shows a MIP of laser-treated surface, where the titanium surface was acquired on a separate channel and displayed in gray. In all reconstructions, viable microorganisms are stained in green, while dead microorganisms are stained in red. Compact biofilm structures with a prevalence of viable cells covering most of the machined, grit-blasted and enamel specimens can be observed. Laser-treated surfaces displayed less dense biofilm structures mainly constituted by microcolonies of approximately 200 μm diameter.</p

Calculations of total surface coverage, and percentage of viable and dead bacteria in th... more Calculations of total surface coverage, and percentage of viable and dead bacteria in the biomass, resulting from CLSM MIP images.</p

A, B, and C, show 500X magnifications of machined, grit-blasted, and laser-treated surfa... more A, B, and C, show 500X magnifications of machined, grit-blasted, and laser-treated surfaces, respectively. E, F, and G, show the same surfaces at 5000X magnification. A similar biofilm formation pattern as in the in vitro experiment can be observed.</p

A: Individual mandibular thermoformed acrylic customized tray obtained using a study cas... more A: Individual mandibular thermoformed acrylic customized tray obtained using a study cast of the lower jaw. B: On the buccal part of the device three half-implants, one for each experimental surface, were fixed horizontally on each side (three on the right and three on the left) using orthodontic 0.1 mm wire.</p

A peristaltic pump is used to obtain a continuous flow of nutrients over the surface of ... more A peristaltic pump is used to obtain a continuous flow of nutrients over the surface of the tested specimens. Culture broth is then discarded.</p

A, B, and C, show 3D reconstructions of machined, grit-blasted, and laser-treated surfac... more A, B, and C, show 3D reconstructions of machined, grit-blasted, and laser-treated surfaces, respectively. A complete coverage of the inner parts of the implant threads with mostly viable cells can be observed in all specimens except for laser-treated surfaces. D (grit-blasted specimen) and E (laser-treated specimen) reconstructions show at a higher magnification the inner part of an implant thread. Laser-treated specimens present few dead microbial cells colonizing the bottom of the threads, while an intense colonization of predominantly viable cells can be found on the inclined surfaces of the threads.</p

A, B, C, and D, show 500X magnifications of machined, grit-blasted, laser-treated and en... more A, B, C, and D, show 500X magnifications of machined, grit-blasted, laser-treated and enamel surfaces. E, F, G, and H, show the same surfaces at 5000X magnification. Grooves were present on the machined titanium surfaces, grit-blasted specimens showed characteristic surfaces with high SR, and laser-treatment left very regular microtextured surface with pits of 18–20 μm diameter.</p

Surface roughness (Ra) and total surface free energy of the tested titanium surfaces and... more Surface roughness (Ra) and total surface free energy of the tested titanium surfaces and reference surface (human enamel).</p

A, B, C, and D, show 500X magnifications of machined, grit-blasted, laser-treated and en... more A, B, C, and D, show 500X magnifications of machined, grit-blasted, laser-treated and enamel surfaces. E, F, G, and H, show the same surfaces at 5000X magnification. Grit-blasted and enamel specimens showed complete surface coverage by a multi-layered biofilm. Machined surfaces showed large microcolonies covering a minor part of the surface, and laser-treated surfaces showed the least biofilm formation.</p

A, B: machined surfaces (titanium displayed in red) showed sparse, dark-gray islets made... more A, B: machined surfaces (titanium displayed in red) showed sparse, dark-gray islets made of carbon (in green) that can be regarded as residues of the machining procedures, incompletely removed by subsequent cleansing. C, D: grit-blasted specimens examined after biofilm formation (highlighted by carbon presence, in red) showed aluminum traces (blue, arrows) corresponding to alumina particles embedded into the titanium surface (green) and still present after biofilm formation. E, F: Enamel surfaces (calcium in green) covered by biofilm structures (carbon in red). No contaminating agents derived from polishing procedures can be observed. G, H: high magnification of grit-blasted and laser-treated specimens, respectively, after biofilm formation. In laser-treated specimens, microorganisms show a colonization pattern where cocci, bacilli and extracellular matrix residues can be found on the edges of the pits. Reduced or no biofilm formation can be seen in the inner part of the pits, which were mostly colonized by streptococcal forms.</p

Clinical Oral Implants Research, Sep 6, 2010

Background: Since the late 1980s dental implants have been used in the indication of single-tooth... more Background: Since the late 1980s dental implants have been used in the indication of single-tooth replacement. Aim: The aim of this study was to evaluate the radiographical and clinical outcome of single-machined Bra°nemark implants with at least 15 years of follow-up. Methods: Fifty-one patients who received 63 single implants between 1987 and 1994 were randomly selected. In this patient group three implants failed (4.8%), leaving 60 implants to be clinically investigated. Mean interproximal probing depth, bleeding and plaque index were measured around each implant. Peri-apical radiographs were compared for marginal bone level between baseline (¼within 6 months after abutment connection) and 2-4 years, 5-8 years and 15-22 years of follow-up. Mean interproximal bone level was measured from the implant shoulder as a reference point. Overall changes in marginal bone level were analyzed with the Friedman test and 2-by-2 comparison between time points was evaluated with the Wilcoxon signed ranks test. Results: The group consisted of 29 males and 22 females with a mean age of 24 years (range 14.7-57.4) at implant placement. Mean follow-up time was 18.5 years (range 15-22). Mean probing depth was 3.9 _ 1.27mm (range 2-10.3). Bleeding and plaque indices were 1.2 _ 0.81 and 0.2 _ 0.48, respectively. Mean bone level after 15-22 years was 1.7 _ 0.88mm (range _0.8 to 5). There was no correlation found between radiographic bone level and probing depth. The Friedman test indicated a statistically significant change in marginal bone level between time points (P < 0.05). Wilcoxon signed ranks test showed a statistically significant difference between baseline and all other time points. After 2-4 years no statistically significant differences could be found. All but one implants (98.3%) were within the currently accepted success criteria corresponding to a maximum accepted bone loss of 4.3mm after 15 years. If one accepts a mean bone level of 2.1mm from the implant shoulder (¼2nd thread), 81.7% of the implants are successful. If a mean interproximal probing depth of 5mm is accepted, 91.7% of the implants are successful. If both these criteria are combined, 76.7% are successful. Conclusions and clinical implications: The machined Bra°nemark implant used as a single-tooth replacement is a predictable solution with high clinical survival and success rates. In general, a steady state bone level can be expected over decades. New criteria for long-term implant success should be determined.

Prosthesis, 2022

Objectives: The aim of this retrospective study is to assess whether axial and tilted implants su... more Objectives: The aim of this retrospective study is to assess whether axial and tilted implants supporting All-on-4 prosthesis show any differences in terms of survival rate, success rate and marginal bone loss (MBL) after a long-term follow-up (mean 9 years). Material and Methods: One hundred and fifty-six implants were included in this study, 78 of which were tilted (Group A) and 78 were axial (Group B). MBL was measured after a mean time of 9 years on periapical radiographs. Success and survival rate were assessed with the Misch criteria. The prevalence of peri-implantitis was calculated. Statistical analysis was conducted to assess comparisons between groups. A Kaplan–Meyer analysis was carried out for the survival rate. Results: A total of 156 implants were analyzed. After a 9-year mean time follow-up, the survival rate was 96.2% in group A and 98.7% in group B; and the success rate was 80.8% in group A and 74.4% in group B. The mean MBL was 1.2 mm (IQR 0.6–1.8) in group A and 1...

Copyright © 2012 Nicolo ̀ Cavalli et al. This is an open access article distributed under the Cre... more Copyright © 2012 Nicolo ̀ Cavalli et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Purpose. The aims of this study were to assess the treatment outcome of immediately loaded full-arch fixed bridges anchored to both tilted and axially placed implants in the edentulous maxilla and to evaluate the incidence of biological and prosthetic complications. Materials and Methods. Thirty-four patients (18 women and 16 men) were included in the study. Each patient received a maxillary full-arch fixed bridge supported by two axial implants and two distal tilted implants. A total of 136 implants were inserted. Loading was applied within 48 hours of surgery and definitive restorations were placed 4 to 6 months later. Patients were scheduled for followup at 6, 12, 18, and 24 months and annually up to 5 years. At each followup pl...

Clinical Oral Implants Research, 2018

Background : Prosthetic function of dental restorations could be impaired by the loss of implants... more Background : Prosthetic function of dental restorations could be impaired by the loss of implants due to technical or biological complications. Evaluation of cumulative implant survival rates is important to predict the effectiveness of implant-supported dental restorations, especially in edentulous patients with severe bone atrophy. Aim/Hypothesis : The aim of this retrospective study was to evaluate the cumulative survival rate (CSR) of full-arch implant-supported restorations placed with the All-on-4 treatment concept after up to 10 years of function. Material and Methods : Clinical records of consecutive patients treated with full-arch implant-supported restorations (All-on-4® treatment concept, Nobel Biocare AB, Gothenburg, Sweden) in the dental clinic IRCCS Istituto Ortopedico Galeazzi in Milan, Italy from 2003 and 2012 with at least 5 years of follow-up were collected and evaluated. Implant survival was defined as an implant supporting a functional prosthesis remaining in function from placement. Cumulative Survival Rate (CSR) was computed by performing a life table analysis at 5 years from loading in all patients and at 10 years from loading in the subgroup that reached that follow-up. Influence of implant position (maxilla or mandible) on implant survival was evaluated through regression analysis. Results : A total of 58 patients treated with 69 rehabilitations supported on 276 implants (NobelSpeedy Groovy or Brånemark MkIV, Nobel Biocare AB, Gothenburg, Sweden) were included. The mean follow-up was 9.3 ± 2.0 years (range 5.8-14.0 years) from loading. Thirty-six were mandibular restorations (144 implants). Four implants in three patients failed due to loss of osseointegration (2 mandible, 2 maxilla). Implant level CSR was 99.6% (n = 276) and 97.6% (n = 80) at 5 and 10 years after loading, respectively. No differences could be found in survival rates for mandibular or maxillary implants (P = 0.764). Conclusions and Clinical Implications : Based on this retrospective noninterventional study, we conclude that implants supporting fullarch rehabilitations performed with the All-on-4 treatment concept have excellent survival rates after up to 10 years of function.

Dentistry Journal, 2020

Peri-implantitis is a biofilm-related disease whose characteristics are peri-implant tissues infl... more Peri-implantitis is a biofilm-related disease whose characteristics are peri-implant tissues inflammation and bone resorption. Some clinical trials report beneficial effects after implantoplasty, namely the surgical smoothening of the implant surface, but there is a lack of data about the development of the bacterial biofilm on those smoothened surfaces. The aim of this study is to evaluate how implantoplasty influences biofilm formation. Three implants with moderately rough surfaces (control) and three implants treated with implantoplasty (test) were set on a tray reproducing the supra- and sub-gingival environment. One volunteer wore this tray for five days. Every 24 h, plaque coverage was measured and, at the end of the period of observartion, the implant surfaces were analyzed using scanning electron microscopy and confocal laser scanning microscopy. The proportion of implant surface covered with plaque was 65% (SD = 7.07) of the control implants and 16% (SD = 0) of the test imp...

Clinical Oral Implants Research, 2019

Background : GBR procedures in the lower jaw represent a challenge for oral surgeons around the w... more Background : GBR procedures in the lower jaw represent a challenge for oral surgeons around the world. Aim/Hypothesis : The aim was to evaluate the efficiency of a non-perforated titanium plate for GBR in the lower jaw. Material and Methods : a CBCT scan was made to obtain a stereolithographic model of the jaw. The titanium plate (Regenplate, Italy) was shaped on the model in order to fit the mandible. After preparing the recipient site and checking the fit, the plate was filled with a graft composed by 50% autologous bone and 50% Bovine derived xenograft (Bio-Oss; Geistlich, Switzerland) and then positioned through the means of titanium screws. Flap release was performed and horizontal mattress suture were made. after 9 months the plate was removed and 3 implants were placed. After other 5 months the final prosthesis were delivered. Results : No exposure occurred during the healing period. At removal, ridge augmentation resulted in 2.5 mm vertically and 3.4 mm horizontally. The gain was measured both on CBCT and clinically. Conclusion and Clinical Implications : Shaping the titanium plate on the model reduced the operative time and the number of fixing screws. The absence of holes in the titanium membrane did not compromised the results of the regeneration. Moreover, it permitted an easier removal of the plate compared to a perforated MESH. More studies are needed to standardise the results.

A, B, C, and D, show 500X magnifications of machined, grit-blasted, laser-treated and en... more A, B, C, and D, show 500X magnifications of machined, grit-blasted, laser-treated and enamel surfaces. E, F, G, and H, show the same surfaces at 5000X magnification. Grit-blasted and enamel specimens showed complete surface coverage by a multi-layered biofilm. Machined surfaces showed large microcolonies covering a minor part of the surface, and laser-treated surfaces showed the least biofilm formation.</p

Clinical Oral Implants Research, Sep 6, 2010

Prosthesis, 2022

Clinical Oral Implants Research, 2018

Dentistry Journal, 2020

Clinical Oral Implants Research, 2019