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

Influence of implant diameter on accuracy of static implant guided surgery: An in vitro study

STATEMENT OF PROBLEM

Static guided implant surgery may be the most accurate method of implant placement to date. However, within the same guided implant system, whether accuracy is affected when placing a larger diameter implant that requires more drills than a smaller diameter implant is unclear.

PURPOSE

The purpose of this in vitro study was to evaluate the influence of implant diameter on the angulation and 3-dimensional (3D) deviations of posterior single implant placement using static guided surgery.

MATERIAL AND METHODS

A polyurethane dental cast was made with an edentulous site at the maxillary right first molar position. Identical implant planning for each of 3 dental implant diameters 3.3, 4.1, and 4.8 mm (Straumann BLT) were made, and surgical guides for each implant diameters were fabricated by stereolithography. Fifteen implants of each diameter (N=45) were placed in simulated casts. A scan body was placed and the cast was scanned using an intraoral scanner. The positional discrepancies of implant placement, including angulation as well as 3D implant cervical and apex area deviations, were compared with the planned position. Linear ANOVA single factor analysis (ɑ=.05) was used, and box plots were made.

RESULTS

The ranges of angulation deviations for 3.3-, 4.1-, and 4.8-mm implants were 3.6 degrees to 6.0 degrees, 3.7 degrees to 7.7 degrees, and 3.1 degrees to 6.7 degrees, respectively. The ranges of 3D implant entry deviations of 3.3-, 4.1-, and 4.8-mm implants were 0.96 to 1.4, 0.85 to 1.72, and 0.89 to 1.78 mm, respectively. The ranges of 3D implant apex of 3.3-, 4.1-, and 4.8-mm implants were 0.63 to 1.21, 0.64 to 1.48, and 0.48 to 1.27 mm, respectively. No statistically significant differences were found in any of the 3 measurements: P=.67 for deviation in angulation; P=.27 for 3D implant deviation of entry; and P=.3 for 3D implant deviation of the apex.

CONCLUSIONS

Implant diameters had no significant effect on placement deviations when a single posterior static guided surgery was used.

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.

Current knowledge about stackable guides: a scoping review

PURPOSE

The rise of stereolithographic surgical guides and digital workflow, combined with a better knowledge of materials and loading principle, has enabled the placement of the temporary prosthesis at the time of implant placement. This scoping review aimed to assess the current knowledge available on stackable guides.

METHODS

The review focused on fully edentulous or requiring total edentulism patients. The procedure studied was the use of stackable guides for edentulous patients in order to place immediate temporary prostheses. The clinical endpoint was immediate placement of the provisional prosthesis after surgery combined with a prior bone reduction using a stackable guide.

RESULTS

12 case reports or case series articles met inclusion criteria, which did not allow an analysis by a systematic review. The included studies were case reports or case series. Most of the articles showed a base stabilized by 3 or 4 bone-pins, anchored in buccal or lingual part. Regarding the accuracy of bone reduction (ranged from 0.0248 mm to 1.98 mm) and implant placement when compared to planned, only 4 articles reported quantitative data. 11 articles showed an immediate loading with the transitional prosthesis after implant placement.

CONCLUSIONS

There are as yet no prospective or comparative studies on the efficiency of this technique. In a reliable way, stackable guides seem to be able to guide the practitioner from the flap elevation to the placement of the temporary screw-retained implant supported prosthesis. Given the lack of studies in this specific field of guided surgery, further studies are needed to confirm the clinical relevance of this technique.

An in-vitro analysis of the accuracy of different guided surgery systems - They are not all the same

OBJECTIVES

Different static computer-assisted implant surgery (sCAIS) systems are available that are based on different design concepts. The objective was to assess seven different systems in a controlled environment.

MATERIALS AND METHODS

Each n = 20 implants were placed in identical mandible replicas (total n = 140). The systems utilized either drill-handles (group S and B), drill-body guidance (group Z and C), had the key attached to the drill (group D and V), or combined different design concepts (group N). The achieved final implant position was digitized utilizing cone-beam tomography and compared with the planned position. The angular deviation was defined as the primary outcome parameter. The means, standard deviation, and 95%-confidence intervals were analyzed statistically with 1-way ANOVA. A linear regression model was applied with the angle deviation as predictor and the sleeve height as response.

RESULTS

The overall angular deviation was 1.94 ± 1.51°, the 3D-deviation at the crest 0.54 ± 0.28 mm, and at the implant tip 0.67 ± 0.40 mm, respectively. Significant differences were found between the tested sCAIS systems. The angular deviation ranged between 0.88 ± 0.41° (S) and 3.97 ± 2.01° (C) (p < .01). Sleeve heights ≤4 mm are correlated with higher angle deviations, sleeve heights ≥5 mm with lower deviations from the planned implant position.

CONCLUSIONS

Significant differences were found among the seven tested sCAIS systems. Systems that use drill-handles achieved the highest accuracy, followed by the systems that attach the key to the drill. The sleeve height appears to impact the accuracy.