Effect of implant angulation and impression technique on impressions of NobelActive implants

Effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques

BACKGROUND

Placing implants deep sub-gingivally may affect the accuracy of implant impression techniques and the fit of final restoration.

PURPOSE

The aim of this in-vitro study was to evaluate the effect of soft tissue thickness on accuracy of conventional and digital implant impression techniques.

METHODS

Four parallel implant analogues (A, B, C, D) placed in each of two epoxy resin models representing edentulous mandible covered by flexible polyurethane material with two different thickness two mm and four mm. A total of sixty impressions performed, thirty impressions for each model divided into four groups (n = 15 per group) GI (C2mm) open tray impression with two mm implant depth, GII (C4mm) open tray impression with four mm implant depth, GIII (D2mm) digital impression with two mm implant depth, GIV (D 4 mm) digital impression with four mm implant depth. Impressions from open tray technique were poured to get stone casts while impressions from digital scanning technique were printed as three-dimensional printed casts. The six inter-implant distances between analogues were measured using Co-ordinate measuring machine, deviations compared to reference models were calculated. Data was collected, tabulated and statistically analyzed using One-way ANOVA test to detect significances between groups.

RESULTS

For conventional impressions there was significant difference between C2mm/C4mm (P < 0.001) regarding interimplant distance, while in digital impressions there was no significant difference between D2mm/D4mm AB(p = 0.110), BC(p = 0.066), CD(p = 0.710), AD(p = 0.084), AC(p = 0.067) and BD(p = 0.072). There was significant difference between conventional and digital impression techniques C2mm/D2mm, C4mm/D4mm (P < 0.001).

CONCLUSION

Within the limitations of this in-vitro study digital impressions provide more accurate outcomes with implants placed deeper subgingivally than conventional impressions.

TRIAL REGISTRATION

Retrospectively registered.

Influence of parallel pins on the angle deviation for placement of dental implants: an in vitro study

The aim of the present study was to analyze and compare the angle deviation of two, four and six adjacent dental implants placed with and without straight parallel pins.

MATERIALS AND METHODS

Two hundred and forty (240) dental implants were selected and randomly allocated into the following study groups: Two dental implants placed with straight parallel pins (Ref.: 144-100, BioHorizons, Birmingham, AL, USA) (n = 10) (2PP); Two dental implants placed without parallel pins (n = 10) (2withoutPP); Four dental implants placed with straight parallel pins hT(n = 10) (4PP); Four dental implants placed without parallel pins (n = 10) (4withoutPP); Six dental implants placed with straight parallel pins (n = 10) (6PP) and Six dental implants placed without parallel pins (n = 10) (6withoutPP). The dental implants randomly assigned to groups 2PP and 2withoutPP were placed into standardized polyurethane models of partially edentulous upper jaws in tooth positions 2.4 and 2.6, the dental implants randomly assigned to groups 4PP and 4withoutPP were placed into standardized polyurethane models of fully edentulous upper jaws in tooth positions 1.6, 1.4, 2.4 and 2.6, and the dental implants randomly assigned to groups 6PP and 6withoutPP were placed into standardized polyurethane models of fully edentulous upper jaws in tooth positions 1.6, 1.4, 1.2, 2.2, 2.4 and 2.6. Afterwards, postoperative CBCT scans and digital impressions were aligned in a 3D implant-planning software to compare the angle deviation (°) of two, four and six adjacent dental implants placed with and without straight parallel pins using the General Linear Model statistical analysis.

RESULTS

Statistically significant differences were found between the angle deviation of 2 dental implants placed with straight parallel pins (p < 0.0001) and between the angle deviation of 4 dental implants placed with straight parallel pins (p = 0.0024); however, no statistically significant differences were found in the angle deviation of 6 dental implants placed with straight parallel pins (p = 0.9967).

CONCLUSION

The use of a straight parallelization pin results in lower angle deviation between two and four adjacent dental implants; however, it is not effective for a larger number of dental implants.

Influence of Implant Impression Methods, Polymer Materials, and Implant Angulation on the Accuracy of Dental Models

The paper presents the influence of impression methods, polymer materials, and implant angulation on the accuracy of the definitive working model for the production of implant-supported dental restorations, based on the analysis of results obtained using different impression methods, materials, and parallel and angulated implants. The study findings indicate that all aforementioned factors impact the accuracy of the definitive working model. Specifically, 20° implant angulation in relation to the vertical plane has a greater impact on the impression accuracy compared to parallel implants. The open and splint method in combination with addition silicone, as well as the splint method and polyether combination yielded more accurate results when using implants under 20° angulation compared to other method and material combinations. The splint method in combination with addition silicone resulted in the smallest mean deviations from the center of the parallel implant base compared to other combinations of methods and materials. Analysis results further revealed statistically significant differences in the measured indicators across impression methods, implants, and polymer materials.

Dimensional accuracy of vinyl polyether and polyvinyl siloxane impression materials in direct implant impression technique for multiple dental implants

Purpose:

The present study compared the dimensional accuracy of vinyl polyether silicone (VPES) and polyvinyl siloxane (PVS) impression materials used for non-splinted (NS) and splinted (S) direct open-tray impression techniques for multiple implants inserted in simulated edentulous mandibles.

Materials and methods:

A mandibular stainless steel model with eight internal connections for implant analogs was fabricated to simulate a clinical scenario. The acrylic resin splinted and non-splinted direct impressions were obtained for both VPES and PVS materials. Seventy-two cast samples were divided into four groups based on the impression techniques and materials used. The dimensional accuracies of the casts were measured in three different axes using a computerized coordinate measuring machine (CMM), and were statistically compared.

Results:

The differences in the distortion values between the VPES and PVS impression materials were not statistically significant. Similarly, the differences between the splinted and non-splinted groups among the VPES and PVS materials were not statistically significant.

Conclusion:

The casts fabricated from VPS or PVS impression materials provide similar dimensional accuracy regardless of the implant splinting method.

The impact of impression coping geometrical design on accuracy of implant impressions: an experimental study

AIM

This in vitro study aimed to evaluate the effect of implant impression coping geometrical designs on the accuracy of open and closed impression techniques and in the parallel and nonparallel implant positions.

MATERIAL AND METHODS

Three custom-made acrylic resin models of three tested implant systems (Straumann®, SIC Invent®, and Osstem®) with diverse coping geometrical designs were evaluated in simulated cases of two parallel and two nonparallel implants. The horizontal and vertical discrepancies were measured and analyzed.

RESULTS

No statistically significant differences between the two impression techniques in either parallel or nonparallel implants were observed. The high retentive design of the Osstem system showed a statistically significant difference.

CONCLUSION

The geometrical design of the impression copings did not affect the accuracy for either the open and closed tray techniques. However, the high retentive coping design of the Osstem implant affected the accuracy in the open tray technique.

Comparison of the accuracy of different impression procedures in case of multiple and angulated implants : Accuracy of impressions in multiple and angulated implants

Background

There is no consensus in the literature regarding the impression procedures in the presence of multiple and angulated implants.

Methods

Three maxillary master models with 6 implants bilaterally positioned in anterior, premolar and molar regions were fabricated. In model 1, all implants were placed in parallel; in models 2 and 3, anterior implants were buccally inclined and posterior implants were distally inclined in 10- and 20-degrees, respectively. Three different impression copings (hexed, non-hex, multi-unit) and two different impression techniques (splinting and non-splinting) were tested. A total of 180 impressions (n = 10 per group) were made using mono-phase vinyl poly-siloxane. Master models and duplicate casts were scanned by a 5-axis laboratory scanner and data were transferred to a software program for the alignment of master and duplicate copings. Coronal and angular deviations were calculated, and data were statistically analyzed.

Results

For angulated models, the lowest deviation values were detected at the splinted non-hex coping group (P < 0.05).

Conclusions

Implant angulation, impression coping type, and splinting the impression copings had significant effects on the accuracy of impressions.

Trial registration

Not applicable.

Implant impression accuracy of parallel and non-parallel implants: a comparative in-vitro analysis of open and closed tray techniques

Background

The outcome of the evaluation of impression techniques accuracy may improve the selection criteria for an ideal technique. The aim was to evaluate the accuracy of the open and closed tray techniques for implant impressions, in a partially edentulous maxilla, replaced with a three-unit fixed partial denture, as well as to assess the effect of implants parallelism on accuracy.

Material and methods

This is an experimental in vitro study to evaluate impressions accuracy of a simulated area restored with an implant retained FPD, using the open and closed tray implant impression techniques. The effect of implant position angulation, parallelism, and implant systems (Straumann, SIC Invent, Osstem) was also evaluated. Three custom-made acrylic resin test models were prepared with two parallel and two non-parallel implants, on either side of a maxillary arch. One hundred and ninety-two impressions were made using monophase VPS impression material. Their master casts were obtained and evaluated for the horizontal and vertical discrepancy. The casts were scanned using a model scanner. The distances between the two reference points were measured.

Results

The Straumann and SIC Invent implants showed no statistically significant differences (Mann-Whitney U test), regarding accuracy for both the open and closed tray impression techniques (P = 0.667 and P = 0.472). There were no significant differences for the parallel and non-parallel implants (P = 0.323 and P = 0.814), respectively, while the Osstem system showed statistically significant differences for both the open and closed tray impression techniques (P = 0.035) and between the parallel and non-parallel implants (P = 0.045). For the vertical discrepancies, significant differences were detected (chi-square test) between the open and closed tray impression techniques (P = 0.037).

Conclusions

Within the limitations of this study, there were generally no significant differences between open and closed, although better results were obtained for the open tray techniques. On the use of the non-parallel implants, the open tray technique provided a better result than the closed tray technique.

Cast accuracy obtained from different impression techniques at different implant angulations (in vitro study)

Background

Angulated implants may result in inaccurate impressions, and the impression technique may affect the accuracy of the definitive cast. This study was designed to compare the dimensional accuracy of casts obtained from three impression techniques for three definitive lower casts with implants at different angulations.

Methods

Three Osseolink implants were placed in three reference models with different angles (parallel, 15° and 30°). Impressions of each model were made with three techniques (n = 10 per group): indirect, unsplinted direct, and acrylic resin-splinted direct technique. Impressions were poured with type IV dental stone. Inter-implant distances were measured for casts using a coordinate measuring machine, and the deviations from the reference models (Δr) were calculated. Data were analyzed using one-way ANOVA followed by post hoc tests to detect significance between groups (α = 0.05).

Results

This study showed that the deviations in micrometers from the reference model were the least for acrylic resin-splinted direct technique (Δr1 = 49.96, Δr2 = 50.36) versus indirect (Δr1 = 93.8, Δr2 = 90.9) and unsplinted direct techniques ((Δr1 = 67.07, Δr2 = 68.66) in 30° angulated implant situation (p value < 0.0001^* for both Δr1 and Δr2). In 15° angulated implants, both the acrylic resin-splinted direct (Δr1 = 44.64, Δr2 = 45.58) and unsplinted direct techniques (Δr1 = 47.39, Δr2 = 55.28) were more accurate than indirect technique (Δr1 = 64.8, Δr2 = 68.3) (p value < 0.0001^* for both Δr1 and Δr2). While in parallel condition, no difference was found between all three techniques (p value = 0.085, 0.056 for Δr1 and Δr2, respectively).

Conclusions

The impression technique affected the accuracy of definitive casts. The acrylic resin splinted direct technique produced the most accurate casts, followed by direct unsplinted and indirect techniques. Furthermore, implant angulation affected the impression accuracy. When implant angulation increased from parallel implants to 30°, the forces of deformation increased, which resulted in increased distortion.

Compressive Resistances and Failure Modes of Abutments With Different Transgingival Heights and Types on Internal Conical Connected Implants

PURPOSE

This study aimed to research the effect of different transgingival heights (THs) and types of abutments on performances including the compressive resistances and fracture modes of abutments on internal conical connected implants.

MATERIALS AND METHODS

Three groups were established: a 1-piece zirconia abutment group (group A), a 2-piece zirconia abutment group (group B), and a 1-piece titanium abutment group (group C). Three THs (2, 3.5, and 5 mm, n = 6) were set as the subgroups of each group. All groups were subjected to a compressive resistance test at a 30 degree angle. The main failure modes were analyzed using scanning electron microscopy and a stereomicroscope.

RESULTS

The compressive resistances of the abutments on the internal conical connected implants were significantly related to the TH (P = 0.004), the type of abutment (P < 0.0001), and the combined effect (P < 0.0001). All of the subgroups in group C exhibited the greatest compressive loads at the same TH. Different types of abutments had different failure modes.

CONCLUSIONS

Both the TH and the type of abutments influenced compressive resistances of the implant-abutment complexes.