Alessandro Pozzi

Clinical Reliability of CAD/CAM Cross-Arch Zirconia Bridges on Immediately Loaded Implants Placed with Computer-Assisted/Template-Guided Surgery: A Retrospective Study with a Follow-Up between 3 and 5 Years

PURPOSE The purpose of this study is to retrospectively evaluate the implant and prosthetic survival and success rates of zirconia-based, implant-supported, screw-retained, cross-arch restorations up to 5 years after placement. MATERIALS AND METHODS Twenty-two consecutive edentulous patients (11 males and females, each; mean age 68.3 years) received 26 CAD/CAM cross-arch zirconia implant bridges (NobelProcera™ Implant Bridge Zirconia; Nobel Biocare AG, Zurich, Switzerland) supported by 4 to 10 implants each. All patients were followed for at least 3 years (range 36-60 months, mean 42.3 months). Clinical assessments were scheduled every 4 months during hygiene maintenance. Outcomes were implant and prosthetic survival rates, prosthetic success rate, any observed clinical complications, patient satisfaction, and soft tissue parameters. Fishers exact test was used to assess associations between categorical variables. RESULTS No dropouts occurred. The overall implant and prostheses survival rate up to 5 years was 100%. Three out of 26 restorations (five out of three hundred forty eight dental units) showed an adhesive chip-off fracture of the veneering ceramic, scoring a cumulative prosthetic success rate of 88.5% at the prosthetic level and 98.6% at the unit level. All 22 patients were functionally and aesthetically highly satisfied with their restorations. Successful soft tissue parameters were found around all implants. CONCLUSIONS Industrially manufactured, zirconia-based, implant-supported, screw-retained, cross-arch restorations are a viable alternative to conventionally manufactured porcelain-fused-to-metal restorations for rehabilitating the edentulous patient.

Minimally invasive treatment of the atrophic posterior maxilla: A proof-of-concept prospective study with a follow-up of between 36 and 54 months

STATEMENT OF PROBLEM In the posterior maxilla, tooth loss is usually associated with alveolar bone resorption and sinus pneumatization, limiting the placement of implants without grafting procedures. PURPOSE The purpose of this study was to evaluate a minimally invasive treatment of the atrophic posterior maxilla, with axial and tilted implants and immediate loading. The research hypothesis was that the combination of a guided, minimally invasive approach and the biomimetic features of computer-aided design and computer-aided manufacturing (CAD/CAM) abutments would be an effective alternative to maxillary sinus floor augmentation procedures with reduced bone resorption around implants. MATERIAL AND METHODS Twenty-seven consecutive participants (female=12, male=15) (mean age 54.18 years) with severe atrophy of the posterior maxilla were treated by using guided surgery with immediately loaded axial (39) and tilted (42) implants supporting CAD/CAM zirconia (39) and titanium (42) abutments (81 total) and partial fixed prostheses. Each participant underwent a computed tomography scan, after which 2 or 3 implants were positioned with a flapless or miniflap approach. The drilling protocol was adapted to the bone density of each implant site to obtain an insertion torque ranging between 40 and 50 Ncm. CAD/CAM customized abutments composed of zirconia or titanium were fixed to the implants with prosthetic screws tightened with a torque of 35 Ncm. An acrylic resin interim restoration reinforced with metal was placed immediately. Five to 6 months after initial loading, a zirconia framework was manufactured, and a definitive prosthesis was placed. Clinical and radiological controls were performed at baseline and after 1 and 3 years to assess implant and prosthesis survival and success rate and compare marginal bone remodeling of axial and tilted implants. Inferential statistics for radiological data were acquired by using the Mann-Whitney U-test. All statistical comparisons were conducted at the .05 significance level. RESULTS The mean follow-up period was 43.3 months (ranging from 36 months to 54 months). The cumulative implant survival rate was 96.3% at 3 years. All prosthetic restorations were stable and in good function, resulting in a cumulative prosthetic survival rate of 100%. Three restorations had chipping of the veneer material; thereafter, the cumulative prosthetic success rate was 91.9%. CONCLUSIONS Treatment of the posterior partially edentulous atrophic maxilla with guided surgery and immediate loading of tilted and straight implants supporting short-span partial fixed dental prostheses is effective.

Immediate Fixed Rehabilitation of the Edentulous Maxilla: A Prospective Clinical and Radiological Study after 3 Years of Loading

PURPOSE The aim of this study was to prospectively evaluate the clinical and radiographic outcomes of immediate full-arch fixed maxillary prosthesis supported by two axial and four tilted implants after 3 years of loading. MATERIALS AND METHODS Thirty-two patients with atrophic maxilla were consecutively enrolled and treated. Each patient received a fixed full-arch maxillary rehabilitation supported by four tilted implants that engaged the posterior and the anterior sinus walls and two axial anterior implants. A total of 192 implants (30 Brånemark System MK IV and 162 NobelSpeedy Groovy, Nobel Biocare AB, Göteborg, Sweden) were inserted and immediately loaded. The definitive restorations were placed 6 months later, and follow-up visits were scheduled every 6 months. During follow-ups, marginal bone loss (MBL), plaque and bleeding scores, and patients satisfaction were recorded. RESULTS All patients reached at least 3-year follow-up examination (range 36-78, average 55.53 months). Two tilted implants failed before delivering the definitive restoration, resulting in a cumulative survival rate of 98.96%. All final prostheses were stable and functional, resulting in a cumulative survival and success rate of 100%. At the 3-year follow-up there was no significant difference in MBL between axial (1.55 ± 0.31 mm) and tilted implants (1.46 ± 0.19 mm) (p = .05). Plaque and bleeding scores decreased over time, while patients satisfaction in both aesthetics and function increased. CONCLUSIONS Implants placement with this configuration could be considered a predictable and cost- and time-effective alternative approach for the immediate restoration of the edentulous maxilla, avoiding bone grafting procedures, even with a medium-term follow-up.

Monolithic Lithium Disilicate Full-Contour Crowns Bonded on CAD/CAM Zirconia Complete-Arch Implant Bridges With 3 to 5 Years of Follow-Up

This study was carried on to assess the clinical performance of a novel restorative concept consisting in single monolithic lithium disilicate full-contour crowns bonded on computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia complete-arch implant bridges, to overcome the drawbacks related to the chipping of porcelain fused to zirconia restorations. Sixteen patients received 18 implant-supported hybrid screw-cement-retained complete-arch restorations, consisting of single monolithic lithium disilicate full-contour crowns bonded on CAD/CAM zirconia frameworks. The restorations were supported by 4-8 implants. All patients were followed up for at least 3 years on function (range 36 to 60 months, mean 49.3 months). Clinical controls were scheduled every 4 months. The outcomes were implant and prosthetic survival and success rates, any complications, patient satisfaction, and soft tissue parameters. No dropouts occurred. The overall implant and prosthesis survival rates were 100%. One of 18 restorations (1 of 236 dental units) showed a chip-off fracture of the veneering ceramic that was polished intraorally without any additional treatment, scoring a cumulative prosthetic success rate of 100%, according to the California Dental Association index. All patients were functionally and esthetically highly satisfied with their restorations. Successful soft tissue parameters were found around all implants. Single monolithic lithium disilicate full-contour crowns, bonded on CAD/CAM screw-retained complete-arch zirconia frameworks, showed favorable preliminary outcomes with medium-term follow-up. However, randomized controlled studies of this technique are required for further conclusive recommendations.

The Implant Biologic Pontic Designed Interface: Description of the Technique and Cone-Beam Computed Tomography Evaluation.

PURPOSE The study aims to evaluate clinically the thickness of the alveolar ridge mucosa underneath a zirconia implant-supported restoration with a modified ovate pontic. MATERIALS AND METHODS Sixty-five patients, 32 women and 33 men (mean age: 65.5 years; range 38-81), were included. A total of 383 implants (303 in the maxilla; 80 in the mandible), supporting 81 full or partial fixed dental prostheses (65 in the maxilla; 16 in the mandible), were either cement- or screw-retained. Three years after loading, a total of 219 pontic sites (153 in the maxilla; 66 in the mandible) were measured, and the thickness of the alveolar ridge mucosa between the prosthetic surface and the underlying bone crest were recorded. RESULTS The overall implant and prosthesis survival rates at 3 years were 98.7% and 100%, respectively. No implant complications were reported, scoring a cumulative implant success rate of 100%. In the maxilla, the overall mean thickness of the alveolar ridge mucosa was 2.32 ± 0.57 mm. In the mandible, the overall mean thickness of the alveolar ridge mucosa was 2.20 ± 0.62 mm. There was no statistical difference between the overall mean values in the maxilla and mandible (p = .471). CONCLUSION This radiologic retrospective study suggests the existence of a physiological barrier, named prosthetic biological width, underneath a novel pontic-designed restoration.

Minimally Invasive Transcrestal Guided Sinus Lift (TGSL): A Clinical Prospective Proof‐of‐Concept Cohort Study up to 52 Months

PURPOSE This study describes a new procedure for sinus elevation using computer-guided planning and guided surgical approach through the use of computer-aided design (CAD)/computer-aided manufacturing (CAM)-generated surgical template in combination with expander-condensing osteotomes thus providing a minimally invasive surgical technique. MATERIALS AND METHODS Sixty-six consecutive patients were treated with 136 implants placed by transcrestal-guided sinus floor elevation technique and the patients were followed for at least 3 years in function. The drilling protocol is customized based on the bone density of each implant site to achieve an insertion torque ranging between 45 and 55 Ncm. Titanium temporary abutments were connected to the implants with prosthetic screws tightened to 35 Ncm and an acrylic resin provisional restoration was adapted and delivered immediately. Six months after initial loading, a definitive CAD/CAM-generated restoration was delivered. Outcome measurements assessed were implant and prosthesis survival rate, biological or biomechanical complications, marginal bone level changes, total alveolar ridge bone height before and after procedure, periodontal parameters measured as well as patients perception of pain levels during recovery period. RESULTS Mean follow-up was 43.96 (range from 36 to 52) months. Cumulative implant survival rate was 98.53% at 3 years. No biological or mechanical complications were encountered and no prosthetic failures occurred during the entire follow-up period. Mean marginal bone loss (MBL) during the first year of function was 0.33 ± 0.36 mm, while at the 3-year follow-up, the mean MBL was 0.51 ± 0.29 mm. The mean residual bone height of the alveolar crest prior to grafting was of 6.7 ± 1.6 mm (range 5.1-9.2 mm), while, the mean bone height gained was 6.4 ± 1.6 mm (range 3.2-8.1 mm). All patients reported low levels of pain and found to have normal periodontal parameters. CONCLUSION This proof-of-concept study suggests that the use of guided surgery to perform transcrestal maxillary sinus floor elevation for alveolar ridge height augmentation is a successful minimally invasive technique for the short- to medium-term follow-up, thus avoiding the extended treatment time and morbidities associated with maxillary sinus floor augmentation.

The smiling scan technique: Facially driven guided surgery and prosthetics

PURPOSE To introduce a proof of concept technique and new integrated workflow to optimize the functional and esthetic outcome of the implant-supported restorations by means of a 3-dimensional (3D) facially-driven, digital assisted treatment plan. METHODS The Smiling Scan technique permits the creation of a virtual dental patient (VDP) showing a broad smile under static conditions. The patient is exposed to a cone beam computed tomography scan (CBCT), displaying a broad smile for the duration of the examination. Intraoral optical surface scanning (IOS) of the dental and soft tissue anatomy or extraoral optical surface scanning (EOS) of the study casts are achieved. The superimposition of the digital imaging and communications in medicine (DICOM) files with standard tessellation language (STL) files is performed using the virtual planning software program permitting the creation of a VDP. CONCLUSIONS The smiling scan is an effective, easy to use, and low-cost technique to develop a more comprehensive and simplified facially driven computer-assisted treatment plan, allowing a prosthetically driven implant placement and the delivery of an immediate computer aided design (CAD) computer aided manufacturing (CAM) temporary fixed dental prostheses (CAD/CAM technology).