Digital Tissue Preservation Concept: A Workflow for Guided Immediate Implant Placement and Restoration

Effect of prefabricated immediate interim prosthesis design and insertion workflow on seating accuracy on implants placed via static computer-assisted implant surgery: A cross-sectional in vitro study

BACKGROUND

Immediate implant restoration by prefabricated prosthesis has multiple benefits. However, the design and insertion workflow of the prosthesis may influence the seating.

PURPOSE

Evaluation of seating accuracy of prefabricated interim prosthesis of different designs and insertion workflows for immediate restoration of implants placed via static computer-assisted implant surgery (sCAIS).

MATERIALS AND METHODS

A maxillary model without incisors was used to plan for two implants at the lateral incisor locations. According to the planned implants, sCAIS surgical template and a four-unit interim prosthesis were designed. Four prostheses were fabricated based on the design and insertion workflow. The first prosthesis involved complete fabrication (CF) of the interim prosthesis, where the interim prosthesis is fabricated for laboratory attachment to abutments. The other three prostheses were produced by partial fabrication (PF), where the interim prosthesis shell was produced with internal spacing between the fitting surface and the abutments. The PF prostheses were cemented on abutments attached to the inserted implants. Three different PF prosthesis designs were included with different levels of internal spacing: 100 μm (PF.1), 200 μm (PF.2), and 300 μm (PF.3). A total of 15 surgical models received implants on which each prosthesis was seated and scanned by a laboratory scanner. The vertical, horizontal, and proximal contact errors were measured.

RESULTS

Although all prostheses were seated on every model, the CF prostheses had greater vertical error, followed by PF.1, PF.2, and PF.3 prostheses, respectively. A similar pattern was observed for proximal contact error, where PF.3 was most superior. PF.3 prostheses had the least horizontal error than the other prostheses.

CONCLUSIONS

All interim prostheses experienced errors at the vertical, horizontal, and proximal surfaces, which can be attributed to deviations of the inserted implants. The PF of interim prosthesis with increased internal spacing for intraoral insertion appeared to reduce seating errors.

A biologically oriented preparation technique (BOPT) for immediate posterior implant placement, immediate provisionalization, and definitive implant crown fabrication: A complete digital workflow

OBJECTIVE

Immediate implants and immediate alveolar sealing have been a widely utilized treatment with high predictability and biological advantages. The improvement in technology has made it possible to simplify clinical processes. The aim of the present report was to describe the complete digital workflow of the Biologically oriented preparation technique for immediate posterior implant, immediate provisionalization and fabrication of definitive implant crowns.

CLINICAL CONSIDERATIONS

The surgical process and prosthetic management to preserve the gingival contours of the extracted natural tooth during immediate implant placement and provisionalization are described. Additionally, during the same clinical intervention, the definitive intraoral digital implant scans for capturing the implant position, peri-implant tissue contours, adjacent and antagonist dentition, and profile emergence of the interim implant crown are captured for the fabrication of the definitive crown.

CONCLUSIONS

Based on the technique described, the immediate implant placement and provisionalization in the posterior area provides biological and clinical advantages, reducing the number of abutment-implant disconnections and the number of clinical appointments, as well as increases patient comfort.

CLINICAL SIGNIFICANCE

The present article describes a technique for an immediate implant placement and provisionalization in the posterior region for maintaining the gingival architecture of the extracted tooth. During the same appointment, the implant position, peri-implant tissue contours, and adjacent and antagonist dentition, and profile emergence of the interim implant crown are captured by using an intraoral scanner and used for the fabrication of the definitive crown. This technique aims to reduce the number of abutment-implant disconnections and clinical appointments.

Atraumatic intraoral scans and virtual hybrid casts for custom implant abutments and zirconia implants: Accuracy of the workflow

STATEMENT OF PROBLEM

Making impressions of 2-piece implants is typically associated with the repeated disassembly and reassembly of superstructures and related to soft-tissue trauma. Intraoral scanning of 1-piece zirconia implants is problematic because scan bodies are not readily available. Whether using virtual hybrid casts generated by merging intraoral scan data with the known surface geometry of abutments can solve these difficulties is not clear because data on accuracy of the workflow are sparse.

PURPOSE

The purpose of this in vitro study was to evaluate the accuracy of virtual hybrid casts with respect to the impact of different gingival situations. The workflow was designed to render pointless the use of impression posts and scan bodies and avoid any displacement of the gingiva.

MATERIAL AND METHODS

The mandibular right first molar in a typodont was replaced with a 2-piece titanium implant with a custom abutment and then a 1-piece zirconia implant. Three situations representing different gingival heights covering the abutments were simulated. Twelve intraoral scans were made for each situation to capture the recordable parts of the abutments, and virtual hybrid casts were constructed by superimposing and merging the intraoral scan data with the original laboratory scan data of the abutments. Hybrid casts were compared with reference data by using the root mean square error. Scan body-related and cast scan-related protocols were performed representing conventional digital workflows. Statistical analysis with the Kolmogorov-Smirnov, Kruskal-Wallis, and Mann-Whitney U tests with the Bonferroni correction was conducted with a statistical software program (α=.05).

RESULTS

Deviation was low in the hybrid casts of the custom abutment when the entire abutment was recorded (6.5 μm; IQR: 3.0 μm), when the preparation margin was disguised (7.0 μm; IQR: 1.0 μm), and when half of the abutment was covered (8.0 μm; IQR: 4.0 μm). The accuracy in the 1-piece zirconia implant was 10.0 μm (IQR: 4.0 μm) when the whole surface of the abutment was visible and 12.5 μm (IQR: 6.0 μm) when the preparation margin was covered. When only half of the abutment was captured, a larger deviation of 22.0 μm (IQR: 7.0 μm) was observed. The hybrid cast concept demonstrated superior accuracy compared with protocols using scan bodies (76.0 μm; IQR: 27.0 μm) and cast scans (23.0 μm; IQR: 15.0 μm).

CONCLUSIONS

Digital intraoral scanning and the generation of virtual hybrid casts provide high accuracy and are suitable for the fabrication of single-implant-supported restorations. The atraumatic procedure avoids tissue manipulation and reduces clinical effort.

Seating accuracy of implant immediate provisional prostheses fabricated by digital workflow prior to implant placement by fully guided static computer-assisted implant surgery: An in vitro study

OBJECTIVES

Evaluation of seating accuracy of implant immediate provisional prostheses fabricated prior to fully guided static computer-assisted implant surgery (sCAIS).

MATERIALS AND METHODS

Two maxillary training models were used to plan for single anterior (S-Ant) and single posterior (S-Post) implant prostheses, and a bridge (B) spanning from an anterior implant (B-Ant) to a posterior implant (B-Post). A commercial software was used to plan the implant location, design the surgical guides and design the provisional prostheses. The master models with the provisional prostheses were scanned to generate virtual master models. For each maxillary model, a total of 10 guides and 10 surgical models were produced. Following implant placements in each surgical model, the provisional prostheses were attached to the implants and were scanned to produce virtual surgical models. The virtual master and surgical models were superimposed to measure the vertical error, the proximal contact error and the proximal contact quality.

RESULTS

The vertical error was greatest for the S-Post (0.41 mm), followed by B-Post (0.29 mm), B-Ant (0.26 mm) and S-Ant (0.21 mm). There was no significant difference in vertical errors among the prostheses. For the proximal contact, the S-Ant had significantly greater error (0.45 mm - 0.46 mm) than S-Post (0.15 mm) and B (0.09 mm - 0.15 mm). A similar pattern was observed for proximal contact quality.

CONCLUSIONS

All prostheses were associated with errors vertically and at the proximal contacts. Therefore, the clinicians who plan to use this workflow should be prepared to adjust the prosthesis after implant insertion.