Transferring emergence profile and position of interim restorative implant fixture. A novel digital technique.

The present technical article describes a protocol to digitally reproduce the emergence profile of an interim implant prosthesis (IP) and to transfer its macrogeometry into the definitive restoration. The purpose of this protocol was to minimize alterations in the gingival architecture developed during the interim restorative phase of a single implant that could potentially jeopardize its esthetic outcome. The process included obtaining an intraoral scan with the interim IP in situ, a duplicate of this intraoral scan that was used to capture the exact position of the implant, and an extraoral scan of the prosthesis. These data could then be imported into IOS software to create a model where the patients' soft tissue was incorporated with precision, allowing for the fabrication of a definitive crown with an optimal soft tissue adaptation. As there are few articles in the scientific literature that have reported a consistent method to replicate the emergence profile of an interim IP, the present technical article aims to highlight the potential of utilizing the emergence profile of an interim IP created by IOS software.

Combination of cone beam computed tomography and CAD-CAM techniques for maintaining natural emergence profile in immediate extraction and/or implant placement and restoration of a central incisor: A dental technique.

For immediate extraction and implant placement, preservation of the natural emergence profile is essential to optimize esthetics. In the technique presented, the Digital Imaging and Communications in Medicine (DICOM) and standard tessellation language (STL) data were merged to simulate the tooth before surgery and to design the interim restoration. The existing tooth and gingival architecture were replicated.

Accuracy of implant placement in the posterior maxilla as related to 2 types of surgical guides: a pilot study in the human cadaver.

STATEMENT OF PROBLEM: The position of implants may have an effect on obtaining osseointegration without complications and on the outcome of the prostheses. PURPOSE: The purpose of this study was to compare the accuracy of implant placement with computer-guided surgery and freehand surgery in the atrophic area of the posterior maxilla. MATERIAL AND METHODS: Six human cadavers (Kennedy-Applegate class I) were included in the study. The specimens were randomly classified into 2 categories by using a computer: computer-guided surgery (n=3) and freehand surgery (n=3). Thirty-nine implants were planned with the software. Two types of surgeries were performed. The preoperative computed tomography data were matched with the postoperative computed tomography data by using voxel-based registration software. The position of the planned implants was compared to the actual position of the implants. A multivariate analysis was used for each variable (bone density, length of implant, implant angulation, and surgical technique) to evaluate the effect of these variables on the implant accuracy (α=.05). RESULTS: The statistical tests (Kolmogorov-Smirnov bootstrap) found that guided surgery offered significantly better accuracy for the platform (P=.002), apex (P=.001), and angle (P<.001). However, the accuracy of the 2 methods was similar for the depth parameter (P=.186). The bone density did not influence the implant placement accuracy. CONCLUSIONS: Computer-guided surgery was more accurate than a freehand approach for placing implants into bilateral edentulous zones in the posterior maxilla.

A retrospective cohort study of 113 patients rehabilitated with immediately loaded maxillary cross-arch fixed dental prostheses in combination with immediate implant placement.

PURPOSE: To retrospectively evaluate the outcome of immediately loaded cross-arch fixed dental prostheses 6 months after loading. A second aim was to compare survival rates of implants placed in healed versus fresh extraction sites. MATERIALS AND METHODS: In total, 113 consecutive patients about to have their maxillae rendered fully edentulous (mean extractions per patient: 6.7 teeth) received four to eight implants each (total number = 675) which were immediately placed in healed sites (323 implants, 47.9%) or fresh sockets (352 implants, 52.1%). Immediate loading of provisional prostheses was performed and all patients were followed up for 6 months. The success criteria included prosthesis success, assessment of individual implant stability and complications. RESULTS: No patients dropped out and all 113 patients received definitive fixed prostheses after 6 months of loading. The overall implant survival rate after 6 months was 99.1%. Six implants were lost in 6 patients (5.3%). Five of them were inserted in fresh extraction sockets (1.4%) and one in a healed site (0.3%). No significant difference (P = 0.1621) was found for implants placed in healed sites versus fresh extraction sites. Ten patients had fractures of the provisional prostheses as complications. CONCLUSIONS: Immediate implant placement and loading resulted in high implant as well as prosthetic survival rates. Placement in healed or fresh extraction bone sites may not influence implant survival.

A retrospective cohort study of 105 patients rehabilitated with immediately loaded mandibular cross-arch bridges in combination with immediate implant placement.

PURPOSE: To evaluate the outcome of immediately loaded cross-arch bridges 4 months after loading. A second aim was to compare survival rates of implants placed in healed versus fresh extraction sites. MATERIALS AND METHODS: In total, 105 consecutive patients about to have their mandibles rendered fully edentulous (mean extractions per patient: 6.1 teeth) received four to six implants each (total number = 448), which were immediately placed in healed sites (266 implants, 59%) or fresh sockets (182 implants: 41%). Immediate loading of provisional prostheses was performed and all patients were followed-up for 4 months. The success criteria included prosthesis success, assessment of individual implant stability and complications. RESULTS: No patient dropped out and all 105 patients received definitive fixed prostheses after four months of loading. The overall implant survival rate after four months was 98.2%. Eight implants were lost in eight patients (8%). Four of them were inserted in fresh extraction sockets (2.2%) and four in healed sites (1.5%). No significant difference (P = 0.4990) was found for implants placed into healed sites versus fresh extraction sites. No complications were reported. CONCLUSIONS: Immediate implant placement and loading resulted in high implant as well as prosthetic survival rates. Placement in healed or fresh extraction bone sites did not influence implant survival.

Guided surgery and presurgical prosthesis: preliminary results of 33 fully edentulous maxillae treated in accordance with the NobelGuide protocol.

OBJECTIVE: The aim of this study was to present the preliminary results of 33 edentulous maxillary patients treated using the Nobelguide (Nobel Biocare AB, Göteborg, Sweden) technique. MATERIALS AND METHODS: Thirty-three patients were treated according to the conventional protocol of the Nobelguide technique in two clinical centers. This group of patients received 211 implants. Monitoring was carried out for over 12-51 months, depending on the patient. The Nobelguide protocol was used for all patients. RESULTS: Of the 211 implants loaded, four were lost (1.9%). The implant survival rate was therefore 98.1%. The prosthetic survival rate was 100%. There were some per-operative complications (four) and some postoperative complications (10 fractures of resin). CONCLUSION: These preliminary results seemed rather promising. These were the first cases of experienced surgeons who needed to learn a new implant placement protocol. It was clear that analysis and understanding of the system were essential in order to obtain such a success. Only one implant was replaced without there being any impact on the prosthesis survival rate which is 100%.

Implant-retained mandibular overdentures: a comparative pilot study of immediate loading versus delayed loading after two years.

STATEMENT OF PROBLEM: Treatment options for an increasing number of completely edentulous patients using fixed restorations may be limited due to anatomical or financial constraints. PURPOSE: The purpose of this pilot study was to compare immediate loading versus conventional delayed loading of implants placed for the retention of mandibular overdentures. MATERIAL AND METHODS: Twenty-six subjects each received 3 implants placed in the symphysis area which were connected with a gold bar. In the experimental group (n=17), the 3 splinted implants were loaded 2 days after surgery; in the control group (n=9), the 3 implants were loaded 3 months after surgery using a conventional 2-stage approach. Recall appointments were scheduled every 3 months during the 2-year follow-up. The following clinical parameters were included and assessed: health of periimplant soft tissues using the bleeding index (BI), plaque index (PI), periimplant probing depth (PIPD), periimplant bone resorption as measured on panoramic radiographs, and implant stability using resonance frequency analysis (RFA). The Mann-Whitney test (alpha=.05) was used to compare each parameter in the 2 groups. RESULTS: After 2 years, no implant failure was recorded in either group. No significant difference was found between the 2 groups after 2 years with regard to BI (P=.33), PI (P=.81), PIPD (P=.61), periimplant bone resorption (P=.32), or RFA (P=.06). After 1 year, periimplant bone loss (P=.05) and PIPD (P=.005) were increased in the control group. CONCLUSIONS: Immediate loading of 3 splinted implants retaining a mandibular overdenture shortens treatment time for prosthesis insertion and shows, after 2 years, results comparable with the delayed approach.