Pera, Paolo

This study clinically and histologically evaluated the performance of implants with different crestal morphologies: tissue-level implants and bone-level implants. Nine patients received at least two adjacent implants in an edentulous area: one bone-level implant (EO) and one tissue-level implant (TG) (total: 23 implants), placed beside each other using a single-stage delayed loading protocol. The implants were rehabilitated with screw-retained fixed partial dentures. Plaque Index (PI), bleeding on probing (BOP), probing depth (PD), and peri-implant bone level were recorded at various postsurgical follow-ups, including 2 and 6 months as well as 1 and 4 years. At 3 months postsurgery, soft tissue biopsy samples were taken from all implant sites and histologically analyzed. Longitudinal assessment of the results (TG vs EO implants) was performed using a linear mixed model with random intercept and by using Spearman correlation or chi-square after visual inspection of the probability distribution. Student t test was used to compare means, and chi-square test was used for dichotomic variables. P < .05 was considered statistically significant. All implants were functional at 4 years. Peri-implant bone resorption was limited, with means of 1.20 ± 0.71 mm and 1.24 ± 0.82 mm for TG and EO implants, respectively. No significant differences in clinical parameters were identified between EO and TG implants. Histologic analysis revealed normal peri-implant soft tissue healing with poor inflammatory infiltrate. Differences in the histologic appearance of soft tissues were more related to patients than implant type. Both implants appeared to be suitable for partial rehabilitation of edentulous arches without differences in the investigated clinical and histologic parameters. However, TG implants showed a greater risk of implant collar exposure.

Objectives: To compare the cleaning efficacy of glycine air polishing against two different professional oral hygiene techniques on implants supporting full-arch fixed prostheses. Method and materials: Thirty patients with a total of 32 implant fixed full-arch rehabilitations in the maxilla and/or mandible (134 implants) were included. After the removal of the screw-retained prostheses, baseline peri-implant spontaneous bleeding (SB), Plaque Index (PI), probing depth (PD), and bleeding on probing (BOP) were recorded (T0). Three oral hygiene treatments were assigned randomly following a split-mouth method: all the patients received glycine air polishing (G) in one side of the arch (n = 32), and sodium bicarbonate air polishing (B) (n = 16) or manual scaling with carbon-fiber curette (C) (n = 16) was performed in the opposite side. After the hygiene procedures, PI and SB were recorded and patient's comfort degree towards the three techniques was analyzed by questionnaires using a rating scale from 1 to 5 (T1). Results: PI reduction was significantly higher for G (T0, 2.88 ± 1.37; T1, 0.04 ± 0.21) and B (T0, 3.13 ± 1.34; T1, 0.0 ± 0.0) as compared with C (T0, 2.15 ± 1.46; T1, 0.44 ± 0.7) (P .001). B reported the highest mean value of SB (T0, 0.0 ± 0.0; T1, 3.42 ± 0.75) compared with G (T0, 0.05 ± 0.21; T1, 1.60 ± 1.05) and C (T0, 0.07 ± 0.24; T1, 0.73 ± 0.91) (P .001). A significant difference in comfort mean score was found between G (4.8 ± 0.5) and B (3.5 ± 1.7) (P = .014), no difference between G and C (4.7 ± 0.7) (P = .38). Conclusion: Professional oral hygiene on implants using glycine air polishing showed high levels of both cleaning efficacy and patients' acceptance. Parole chiave: dental implants, full-arch, glycine air polishing, oral hygiene, sodium bicarbonate air polishing

The aim of the present report was to evaluate the clinical outcomes of edentulous jaws rehabilitated with the Brånemark Novum protocol over a 16-year period. Between April and November 2001, four patients (three males, one female) were rehabilitated with fixed full-arch rehabilitations supported by three immediately loaded implants following the Brånemark Novum protocol. Cumulative survival rates (CSRs) of the implants and prosthesis, bleeding on probing (BOP), Plaque Index (PI), probing depth (PD), implant stability quotient (ISQ; as measured through resonance frequency analysis [RFA]), and peri-implant bone resorption were evaluated over time, up to the 16-year follow-up. At 16 years of follow-up, no implant failed (CSR 100%) and no prosthesis needed to be substituted (CSR 100%). During the period between the 11th and 16th year of follow-up, bone level (mean: 2.2 mm at 16 years) and RFA values remained stable. At the 16-year follow-up, the implants presented high PI (79.2%) but low BOP (10.4%) values. Mean PD was 3.30 mm (range: 2 to 6 mm). One biologic complication was detected on a central implant (crater-form bone destruction), and several prosthodontic complications occurred during the 16 years (fractures of resin or teeth), the majority of which were registered on the same parafunctional patient. This is the first description of the Brånemark Novum protocol rehabilitation with a 16-year followup. The outcomes demonstrated very good long-term outcomes for this protocol.

Purpose: To compare clinical outcomes of immediate vs delayed implant loading in edentulous maxillae with full-arch fixed prostheses. Materials and Methods: Two patient groups were identified for this study: (1) the test group (TG), which included 34 patients (19 women, 15 men; mean age 56.7 years) treated with the Columbus Bridge Protocol with 4 to 6 postextractive implants loaded within 24 hours (163 implants total); and (2) the control group (CG), which included 15 patients (6 women, 9 men; mean age 59.96 years) treated with a traditional two-stage delayed loading rehabilitation using 6 to 9 implants inserted in healed sites (97 implants total). All patients were rehabilitated with full-arch fixed prostheses in the maxilla. Results: At the 10-year follow-up, no difference in the implant cumulative survival rate between the TG (93.25%) and CG (94.85%) was found. Mean bone loss was significantly lower in the TG (mean: 2.11 mm) compared to the CG (mean: 2.65 mm). All original prostheses were maintained and functioning satisfactorily. Conclusion: Maxillary full-arch immediate loading represents a valid alternative to the traditional delayed loading rehabilitation.

Purpose: To evaluate plaque accumulation, peri-implant soft tissue inflammation, and bone resorption in patients with immediately loaded implants supporting fixed full-arch prostheses. Materials and Methods: A convenience sample of 72 patients treated with fixed full-arch prostheses supported by four to six immediately loaded implants was selected. Bleeding on probing (BOP), Plaque Index (PI), and peri-implant bone loss were measured. The Sixth European Workshop on Periodontology definitions of mucositis and peri-implantitis were used, and collected data were analyzed using a nonparametric test (Spearman's rank correlation). Correlation coefficients (ρ) were defined as follows: 0.2 = very weak; 0.2 to 0.39 = weak; 0.4 to 0.59 = moderate; 0.6 to 0.79 = strong; 0.8 to 1.0 = very strong. Results: A total of 331 implants were analyzed. The mean follow-up observation time was 5.8 years (range: 1 to 14 years); mean PI and BOP were 61.7% and 21.1%, respectively; and mean bone loss was 0.89 mm (standard deviation [SD] 1.09). The mean probing depth was 1.8 mm (range: 0.5 to 5 mm). Five patients presented with one implant each affected by peri-implantitis (6.9%), and 15 patients presented with at least one implant affected by mucositis (20.8%). No correlation was found between PI and bone resorption (P = .08). Very weak correlations were found between BOP and bone resorption (ρ = 0.18; P = .001) and between PI and BOP (ρ = 0.13, P = .019). Conclusion: The results suggest that plaque accumulation is correlated with peri-implant mucositis; however, plaque accumulation alone does not appear to be associated with bone resorption.

Purpose: This paper describes a new ultrasonic instrument (tipholder DB1 with crown prep tip inserts) designed to optimize prosthodontic margin repositioning and finishing. Materials and Methods: The insert movement was assessed, and it was demonstrated that tipholder DB1 provides its inserts with an elliptical-like movement, making the entire insert surface able to cut. Then, 20 extracted teeth were prepared using tipholder DB1, sonic instruments, and traditional drills. Dental surface roughness produced using each of the three tools was measured using a roughness tester. Results were compared using univariate analysis of variance and Bonferroni post hoc test. Results: The roughness produced using tipholder DB1 with crown prep insert presented no statistically significant differences compared to the roughness produced using sonic instruments and traditional drills. Conclusion: Tipholder DB1 with crown prep inserts is a promising treatment for margin repositioning and finishing.

Purpose: The aim of this split-mouth study was to evaluate the behaviour of soft and hard tissue around implants with two different surface treatments. Materials and methods: 10 patients (5 men, 5 women) were treated with fixed partial dentures supported by implants. Each patient received at least 2 implants (1 control, 1 test) into an edentulous quadrant. The control implants (Osseotite, OSS) had a dual acid-etched (DAE) surface in the apical portion and a machined coronal part; test implants (Full Osseotite, FOSS) had a completely DAE surface. Machined healing abutments were placed on control implants and DAE abutments on test ones. After 3 months from surgery, a mini-invasive sample of soft tissue was collected from the first 7 patients recruited for the study (4 women and 3 men). The samples were analysed by microRNA (miRNA) microarray. Standardised periapical radiographs were taken to investigate interproximal bone levels at baseline (immediately after implant insertion), 2 months, 6 months, and 1 year post-implant placement. Plaque index (PI), bleeding on probing (BOP) and periodontal depth (PD) were recorded at 3 and 6 weeks, and at 2, 3, 6 and 12 months post-implant placement. Differences in bone resorption over time were evaluated with the Friedman test followed by post-hoc Wilcoxon signed ranks tests. Differences in bone resorption, PI, BOP and PD between the two types of implant over time were assessed by the repeated measures ANOVA test for ranked data. A p ≤0.05 was considered statistically significant. Statistical analyses were carried out with SPSS v.20. Microarray data were processed by GeneSpring® software and their overall variability was examined by box-plot analysis, scatter-plot analysis, hierarchical cluster analysis (HC) and principal component analysis (PCA). Individual miRNAs modulated by the experimental treatments were identified by volcano-plot (thresholds 2-fold and P0.05), support vector machine and k-nearest neighbour analyses. The results of miRNA microarray were compared with measured clinical parameters. Results: Control implants showed greater bone resorption compared to test ones; however, the difference was not statistically significant. Greater plaque accumulation was found for test surfaces, but the difference was not statistically significant. No statistically significant differences in BOP and PD were found. miRNA microarray analysis led to the following findings: - Implant sites with low plaque accumulation and absence of BOP had a gene expression profile similar to those with plaque deposits and an absence of BOP; sites with both high PI and high BOP had a completely different profile. - Implant sites with BOP present presented similar gene expression profiles independently from the type of implant surface. - Implant sites with high PI and normal bone resorption had a different expression profile from the other experimental conditions. - Implant sites with normal bone resorption despite high BOP differed from the other experimental conditions. This gene expression profile resembled that of FOSS implants. - Implant surface affected bone resorption: groups having similar bone resorption characteristics (normal vs. increased) clustered differently according to the implant type. Conclusions: DAE surfaces showed more plaque accumulation than machined ones; however, this did not affect the health of soft peri-implant tissue. In fact, BOP values did not differ between test and control implants. Furthermore, DAE surfaces induced lower bone resorption compared with machined ones. miRNA analysis suggested that soft tissue inflammation is more related to a specific host characteristic (gene expression profile) rather than to the presence of plaque or to a given implant surface. Some specific miRNA profile might be able to protect implant sites from bleeding and bone resorption irrespective of plaque accumulation. Possible future applications of the present findings include the use of the identified biomarkers for diagnosis and as drugs or coatings for implant surfaces in order to improve the health of peri-implant tissues. Parole chiave: dental implants, peri-implant tissue, microRNA, titanium surfaces

Aim: The purpose of this in vitro study is to assess the passive fit of prosthetic metal frameworks obtained through a novel digital impression system, for full-arch rehabilitations on multiple implants. Materials and methods: Five master casts, reproducing edentulous jaws with 4 tilted implants, were poured (Groups: MC #1, MC #2, MC #3, MC #4, MC #5). An intraoral scanner system [True Definition Scanner, 3M ESPE, St. Paul, MN, USA] was used to perform five digital impressions (DI) of each master cast (n=25). The implant position was detected with 4 special scan bodies [Toothless, Simbiosi srl, Empoli Firenze, Italy]. A single DI, presenting mean values compared to the others, was selected from each group in order to fabricate a metal framework with CAD-CAM technology (n=5). Passive fit was assessed with the Sheffield Test, screwing each framework on the corresponding master cast. A stereomicroscope [Wild M3Z, Wild Heerbrugg, Heerbrugg, Switzerland] (40x magnification) was used to record maximum gap values at the framework-implant analog interface. Results: Sheffield test reported the following mean values of gap: MC #1 = 0.024 ± 0.019 mm (range: 0.003-0.044 mm), MC #2 = 0.022 ± 0.014 mm (range: 0.003-0.047 mm), MC #3 = 0.027 ± 0.015 mm (range: 0.003-0.045 mm), MC #4 = 0.021 ± 0.012 mm (range: 0.003-0.037 mm), MC #5 = 0.021 ± 0.016 mm (range: 0.002-0.046 mm). No statistically significant differences were found among the groups (p>0.05). Conclusion: Within the limits of this study, digital impression represents a reliable method to fabricate full-arch implant frameworks provided with passive fit. Parole chiave: intraoral scanner, digital impression, impression accuracy, implant, passive fit, prosthetic framework

Purpose: The aim of this study was to analyze through a three-dimensional finite element analysis (3D-FEA) stress distribution on four implants supporting a fullarch implant-supported fixed prosthesis (FFP) using different prosthesis designs. Materials and Methods: A 3D edentulous maxillary model was created and four implants were virtually placed into the maxilla and splinted, simulating an FFP without framework, with a cast metal framework, and with a carbon fiber framework. An occlusal load of 150 N was applied, stresses were transmitted into peri-implant bone, and prosthodontic components were recorded. Results: 3D-FEA revealed higher stresses on the implants (up to +55.16%), on peri-implant bone (up to +56.93%), and in the prosthesis (up to +70.71%) when the full-acrylic prosthesis was simulated. The prosthesis with a carbon fiber framework showed an intermediate behavior between that of the other two configurations. Conclusion: This study suggests that the presence of a rigid framework in full-arch fixed prostheses provides a better load distribution that decreases the maximum values of stress at the levels of implants, prosthesis, and maxillary bone.

Purpose: The aim of this study was to evaluate the behavior of hard and soft tissue around implants with different surface treatments. Materials and Methods: Eight patients were identified for this study. Each patient received at least 2 implants (1 control, 1 test) into an edentulous quadrant, for a total of 10 pairs of implants. Two types of implants were used: hybrid implants (control) with a dual acid-etched surface in their apical portion and a machined coronal part, and test implants with an acidetched surface throughout their entire length. Standardized periapical radiographs were taken at baseline, 3 months, 6 months, and 1 year post implant placement and then annually until the 6-year follow-up. Bleeding on probing (BOP) and Plaque Index (PI) were recorded annually. Probing depth (PD) was recorded at the 6-year follow-up. Results: Moderate crestal bone remodeling was observed during the 1-year postimplant placement evaluation (P = .001), and test implants revealed smaller marginal bone resorption (P = .030). No significant changes in bone level were observed between the 1-year and the 6-year follow-up appointments, and a significantly smaller bone resorption was found at test implants. No statistically significant differences in bone resorption were found between maxilla and mandible. No statistically significant differences were detected between test and control implants for BOP, PI, or PD. Conclusions: The preliminary results suggest that implant surface characteristics might affect the bone remodeling phase subsequent to the surgical trauma. However, once osseointegration was established, implant surfaces did not affect bone maintenance over time. Implant surfaces did not affect soft tissue behavior. The results of this pilot study need to be confirmed in a study with a larger sample size and over a longer time frame.