Custom-made computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) synthetic bone grafts for alveolar ridge augmentation: A retrospective clinical study with 3 years of follow-up.

PURPOSE: To report on the results obtained with computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) custom-made synthetic hydroxyapatite/beta-tricalcium-phosphate (HA/beta-TCP) bone grafts in alveolar ridge augmentation for dental implant placement. METHODS: The procedure included: (1) cone-beam computed tomography (CBCT) of the bone defect; (2) virtual design of the custom-made onlay bone grafts; (3) milling of grafts from a pre-formed block of synthetic HA/beta-TCP; and (4) bone reconstructive surgery. Implants were placed 8 months later. The patients were followed for 3 years. The study outcomes were: (1) intra- and immediate post-operative complications; (2) 8-month vertical and horizontal bone gain; (3) implant survival; (4) implant-crown success; and (5) peri-implant marginal bone loss (MBL). RESULTS: Twenty-six patients underwent ridge augmentation with custom-made CAD/CAM HA/beta-TCP onlay grafts. Eight months later, these patients were rehabilitated with dental implants. During surgery, 25/26 (96.1%) of the grafts adapted well to the bone defect. Immediate post-operative complications were pain and swelling (2/26 patients: 7.6%), and bone graft exposure (3/26: 11.5%); one exposure led to infection, removal of the graft, and failure of the procedure. Excellent integration of the other grafts was observed 8 months after the regenerative procedure, with mean vertical and horizontal bone gains of 2.10 mm (± 0.35) and 2.96 mm (± 0.45), respectively. Twenty-five implants were placed and restored with single crowns. Three years later, all implants were in function. The 3-year implant crown success rate and peri-implant MBL were 92.0% and 0.7 mm (±0.19), respectively. CONCLUSIONS: With custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts reconstruction of small vertical and/or horizontal defects of the alveolar ridge was obtained; this enabled implant placement, with high implant-crown success rate after 3 years. Further studies are needed to validate this technique. STATEMENT OF CLINICAL RELEVANCE: Custom-made CAD/CAM synthetic HA/beta-TCP onlay grafts may represent an option for regeneration of small bone defects prior to implant placement.

Congruence between Meshes and Library Files of Implant Scanbodies: An In Vitro Study Comparing Five Intraoral Scanners.

PURPOSE: To compare the reliability of five different intraoral scanners (IOSs) in the capture of implant scanbodies (SBs) and to verify the dimensional congruence between the meshes (MEs) of the SBs and the corresponding library file (LF). METHODS: A gypsum cast of a fully edentulous maxilla with six implant analogues and SBs screwed on was scanned with five different IOSs (PRIMESCAN®, CS 3700®, MEDIT i-500®, ITERO ELEMENTS 5D®, and Emerald S®). Ten scans were taken for each IOS. The resulting MEs were imported to reverse engineering software for 3D analysis, consisting of the superimposition of the SB LF onto each SB ME. Then, a quantitative and qualitative evaluation of the deviations between MEs and LF was performed. A careful statistical analysis was performed. RESULTS: PRIMESCAN® showed the highest congruence between SB MEs and LF, with the lowest mean absolute deviation (25.5 ± 5.0 µm), immediately followed by CS 3700® (27.0 ± 4.3 µm); the difference between them was not significant (p = 0.1235). PRIMESCAN® showed a significantly higher congruence than MEDIT i-500® (29.8 ± 4.8 µm, p < 0.0001), ITERO ELEMENTS 5D® (34.2 ± 9.3 µm, p < 0.0001), and Emerald S® (38.3 ± 7.8 µm, p < 0.0001). CS 3700® had a significantly higher congruence than MEDIT i-500® (p = 0.0004), ITERO ELEMENTS 5D® (p < 0.0001), and Emerald S® (p < 0.0001). Significant differences were also found between MEDIT i-500® and ITERO ELEMENTS 5D® (p < 0.0001), MEDIT i-500® and Emerald S® (p < 0.0001), and ITERO ELEMENTS 5D® and Emerald S® (p < 0.0001). Significant differences were found among different SBs when scanned with the same IOS. The deviations of the IOSs showed different directions and patterns. With PRIMESCAN®, ITERO ELEMENTS 5D®, and Emerald S®, the MEs were included inside the LF; with CS 3700®, the LF was included in the MEs. MEDIT i-500® showed interpolation between the MEs and LF, with no clear direction for the deviation. CONCLUSIONS: Statistically different levels of congruence were found between the SB MEs and the corresponding LF when using different IOSs. Significant differences were also found between different SBs when scanned with the same IOS. Finally, the qualitative evaluation revealed different directions and patterns for the five IOSs.

An Experimental Strategy for Capturing the Margins of Prepared Single Teeth with an Intraoral Scanner: A Prospective Clinical Study on 30 Patients.

Purpose: To present an experimental strategy for successfully capturing the margins of prepared single teeth with an intraoral scanner (IOS). Methods: The protocol was as follows: (1) an intraoral impression was captured with an IOS, without taking care of the visibility of the margins; (2) a partial analog impression was taken by means of a 3D-printed custom tray filled with polyvinylsiloxane light, after the removal of a retraction cord; (3) the hollow portion of the analog impression, with the preparation margins clearly visible, was scanned extraorally with the same IOS; (4) the scan of the analog impression was imported into computer-assisted-design (CAD) software, where its normals were inverted; (5) the scan with inverted normals was registered on the first intraoral scan, and replaced it; (6) the technician designed the final restoration, which was fabricated and delivered for application. The study outcomes were: (1) the marginal adaptation of the final crown; (2) the quality of interproximal contacts; and (3) the quality of occlusal contacts. Results: Thirty patients (18 males, 12 females; mean age 51.3 ± 11.6 years) were selected for this study. All these patients were restored with a monolithic translucent zirconia crown, fabricated following the aforementioned protocol. The clinical precision and the marginal adaptation of the crowns were optimal, interproximal contact points were perfect, and the only necessary adaptations were occlusal, with some minor precontacts that had to be polished. Conclusions: The present protocol seems to be compatible with the fabrication of clinically precise zirconia crowns. Further studies are needed to confirm these results.

A novel guided surgery system with a sleeveless open frame structure: a retrospective clinical study on 38 partially edentulous patients with 1 year of follow-up.

BACKGROUND: This retrospective clinical study aims to present results of experience with a novel guided surgery system with a sleeveless, open-frame structure, in which the surgical handpiece (not the drills used for preparation) is guided. METHODS: This study was based on an evaluation of the records of partially edentulous patients who had been treated with a sleeveless open-frame guided surgery system (TWIN-Guide®, 2Ingis, Brussels, Belgium), between January 2015 and December 2017. Inclusion criteria were patients with good systemic/oral health and a minimum follow-up of 1 year. Exclusion criteria were patients who had been treated without a guide, or with a guide with sleeves, patients with systemic/oral diseases and who did not have a follow-up of 1 year. The main outcomes were surgical (fit and stability of the surgical guide, duration of the intervention, implant stability, and any intra-operative or immediate post-operative complication), biologic, and prosthetic. RESULTS: Thirty-eight patients (24 males, 14 females; mean age 56.5 ± 14.0 years) were included in the study. These patients had been treated with 110 implants inserted by means of 40 sleeveless, open-frame guides. With regard to fit and stability, 34 guides were excellent, 4 acceptable, and 2 inadequate for use. The mean duration of the intervention was 23.7 (± 6.7) minutes. Immediately after placement, 2 fixtures were not stable and had to be removed. Two patients experienced pain/swelling after surgery. The 108 surviving implants were restored with 36 single crowns and 32 fixed partial prostheses (24 two-unit and 8 three-unit bridges); these restorations survived until the 1-year follow-up, with a low incidence of biologic and prosthetic complications. CONCLUSIONS: Within the limits of this study, this novel guided surgery system with sleeveless, open frame-structure guides seems to be clinically reliable; further studies on a larger sample of patients are needed to confirm these outcomes.

Combining Intraoral and Face Scans for the Design and Fabrication of Computer-Assisted Design/Computer-Assisted Manufacturing (CAD/CAM) Polyether-Ether-Ketone (PEEK) Implant-Supported Bars for Maxillary Overdentures.

PURPOSE: To present a digital method that combines intraoral and face scanning for the computer-assisted design/computer-assisted manufacturing (CAD/CAM) fabrication of implant-supported bars for maxillary overdentures. METHODS: Over a 2-year period, all patients presenting to a private dental clinic with a removable complete denture in the maxilla, seeking rehabilitation with implants, were considered for inclusion in this study. Inclusion criteria were fully edentulous maxilla, functional problems with the preexisting denture, opposing dentition, and sufficient bone volume to insert four implants. Exclusion criteria were age < 55 years, need for bone augmentation, uncompensated diabetes mellitus, immunocompromised status, radio- and/or chemotherapy, and previous treatment with oral and/or intravenous aminobisphosphonates. All patients were rehabilitated with a maxillary overdenture supported by a CAD/CAM polyether-ether-ketone (PEEK) implant-supported bar. The outcomes of the study were the passive fit/adaptation of the bar, the 1-year implant survival, and the success rates of the implant-supported overdentures. RESULTS: 15 patients (6 males, 9 females; mean age 68.8 ± 4.7 years) received 60 implants and were rehabilitated with a maxillary overdenture supported by a PEEK bar, designed and milled from an intraoral digital impression. The intraoral scans were integrated with face scans, in order to design each bar with all available patient data (soft tissues, prosthesis, implants, and face) in the correct spatial position. When testing the 3D-printed resin bar, 12 bars out of 15 (80%) had a perfect passive adaptation and fit; in contrast, 3 out of 15 (20%) did not have a sufficient passive fit or adaptation. No implants were lost, for a 1-year survival of 100% (60/60 surviving implants). However, some complications (two fixtures with peri-implantitis in the same patient and two repaired overdentures in two different patients) occurred. This determined a 1-year success rate of 80% for the implant-supported overdenture. CONCLUSIONS: In this study, the combination of intraoral and face scans allowed to successfully restore fully edentulous patients with maxillary overdentures supported by 4 implants and a CAD/CAM PEEK bar. Further studies are needed to confirm these outcomes.

A Novel Full-Digital Protocol (SCAN-PLAN-MAKE-DONE®) for the Design and Fabrication of Implant-Supported Monolithic Translucent Zirconia Crowns Cemented on Customized Hybrid Abutments: A Retrospective Clinical Study on 25 Patients.

PURPOSE: To present a novel, full-digital protocol for the design and fabrication of implant-supported monolithic translucent zirconia crowns cemented on customized hybrid abutments. METHODS: The present retrospective clinical study was based on data from patients who had been treated with single Morse-taper connection implants (Exacone®, Leone Implants, Florence, Italy) and were prosthetically restored with monolithic translucent zirconia crowns, cemented on customized hybrid abutments. The full-digital protocol (SCAN-PLAN-MAKE-DONE®) consisted of 8 phases: (1) intraoral scan of the implant position with scanbody; (2) computer-assisted design (CAD) of the individual abutment (saved as "supplementary abutment design" in external folder) and temporary crown; (3) milling of the individual zirconia abutment and of the temporary polymethyl-methacrylate (PMMA) crown, with extraoral cementation of the zirconia abutment on the relative titanium bonding base, to generate an individual hybrid abutment; (4) clinical application of the individual hybrid abutment and cementation of the temporary PMMA crown; (5) two months later, intraoral scan of the individual hybrid abutment in position; (6) CAD of the final crown with margin line design on the previously saved "supplementary abutment design", superimposed on the second scan of the abutment in position; (7) milling of the final crown in monolithic translucent zirconia, sintering, and characterization; and (8) clinical application of the final crown. All patients were followed for a period of 1 year. The primary outcomes of this study were the marginal adaptation of the final crown (checked clinically and radiographically), the quality of occlusal and interproximal contact points at delivery, and the aesthetic integration; the secondary outcomes were the 1-year survival and success of the implant-supported restoration. An implant-supported restoration was considered successful in the absence of any biological or prosthetic complication, during the entire follow-up period. RESULTS: In total, 25 patients (12 males, 13 females; 26⁻74 years of age; mean age 51.1 ± 13.3 years) who had been restored with 40 implant-supported monolithic translucent zirconia crowns were included in this study. At delivery, the marginal adaptation was perfect for all crowns. However, there were occlusal issues (2/40 crowns: 5%), interproximal issues (1/40 crowns: 2.5%), and aesthetic issues (1/40 crowns: 2.5%). The overall incidence of issues at delivery was therefore 10% (4/40 crowns). At 1 year, one implant failed; thus the survival of the restorations was 97.5% (39/40 crowns in function). Among the surviving implant-supported restorations, three experienced complications (one loss of connection between the hybrid abutment and the implant, one decementation of the zirconia abutment, and one decementation of the zirconia crown). The success of restorations amounted to 92.4%. CONCLUSIONS: The restoration of single Morse-taper connection implants with monolithic translucent zirconia crowns cemented on customized hybrid abutments via the novel SCAN-PLAN-MAKE-DONE® full-digital protocol seems to represent a reliable treatment option. However, further studies on a larger number of patients and dealing with different prosthetic restorations (such as implant-supported fixed partial prostheses) are needed to confirm the validity of this protocol.