Effect of coded healing abutment height and position on the trueness of digital intraoral implant scans

Effect of scan pattern on the scan accuracy of a combined healing abutment scan body system

STATEMENT OF PROBLEM

A recently introduced scan body combined with a contoured healing abutment enables digital scans of the implant while its healing abutment shapes the soft tissue for an appropriate emergence profile. However, information on the effect of different scan patterns on the scan accuracy of this new system is lacking.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of scan pattern on the accuracy of digital implant scans by using a combined healing abutment-scan body system.

MATERIAL AND METHODS

A combined healing abutment-scan body system was secured on a single implant at the right first molar site in a dentate mandibular model. A master reference model was generated by scanning the model with an industrial light scanner. The model was then scanned with 4 different scan patterns (SP-A, SP-B, SP-C, and SP-D) by using an intraoral scanner (TRIOS 3). Test scans (n=8) were superimposed over the master reference model by using a metrology software, and distance and angular deviations were calculated. Distance and angular deviation data were analyzed with a multivariate analysis of variance and the Tukey honestly significant difference tests for trueness and precision (α=.05).

RESULTS

Distance deviations (trueness [P=.461] and precision [P=.533] deviations) in the scans were not significantly affected by the scan pattern. Scan pattern affected the trueness (P=.001) and precision (P=.002) when angular deviations were considered. In terms of trueness, SP-D resulted in the highest angular deviations in scans (P≤.031), while the difference in deviations in scans obtained by using other scan patterns was not significant (P≥.378). When angular deviation data were considered, SP-D resulted in lower scan precision than SP-A (P=.014) and SP-B (P=.007). The precision of scans using SP-C was similar to the precision of the scans made by using other scan patterns (P≥.055) in terms of angular deviations.

CONCLUSIONS

The scan accuracy of a combined healing abutment-scan body system was affected by the scan pattern. The scans performed with SP-D presented the lowest accuracy considering the angular deviation data and, therefore, may be the least favored among the patterns tested for scanning a combined healing abutment-scan body system.

Effect of tooth color on the accuracy of intraoral complete arch scanning under different light conditions using a zirconia restoration model

STATEMENT OF PROBLEM

Information regarding the effect of tooth color under different light conditions on the accuracy of intraoral complete arch scanning is limited.

PURPOSE

The purpose of this in vitro study was to evaluate the effect of color and ambient light conditions on the accuracy of mandibular complete arch scanning with an intraoral scanner (IOS) using a zirconia restoration model with different shades.

MATERIAL AND METHODS

Five mandible dentition models with zirconia restorations of different shades were fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM). The spectral reflectance and transmittance curves were collected with a spectrophotometer to determine color parameters (Rb, T, S+A, L*, a*, b*, C*, and h). Under 4 different lighting conditions: no light (ZL), natural light (NL), room light (RL), and chair light (CL), each model was scanned 10 times by using an IOS (TRIOS 3). Three-dimensional (3D) deviation analysis and a linear deviation analysis were performed for an accurate quantitative measurement of intraoral scanning. The multivariate test was used to determine significant differences in 3D deviation and linear deviation among groups. The multiple linear regression test was conducted to investigate the relevant independent factors of mean absolute 3D deviation.

RESULTS

The 3D deviation analysis showed that the mean absolute 3D deviation of 3M2 model scanning was the lowest (P<.001). Moreover, under CL and RL, the accuracy results from the 3M2 model scan were demonstrated as significantly better than the tested scans under other light conditions (P=.021). The result of the linear deviation analysis indicated that the variation in distance was only significant between the bilateral canines (P=.032). Ambient light conditions, C*, and h were factors influencing mean absolute 3D deviation (R2=0.593, P<.001).

CONCLUSIONS

Color change influenced the accuracy of intraoral mandibular complete arch scanning under different light conditions. This effect may be attributable to the interaction between the ambient light condition and color parameters such as C* and h.

Influence of implant scan body design (height, diameter, geometry, material, and retention system) on intraoral scanning accuracy: A systematic review

PURPOSE

To evaluate the influence of implant scan body (ISB) design (height, diameter, geometry, material, and retention system) on the accuracy of digital implant scans.

MATERIAL AND METHODS

A literature search was completed in five databases: PubMed/Medline, Scopus, Embase, World of Science, and Cochrane. A manual search was also conducted. Studies reporting the evaluation of ISB design on the accuracy of digital scans obtained by using IOSs were included. Two investigators evaluated the studies independently by applying the Joanna Briggs Institute critical appraisal. A third examiner was consulted to resolve any lack of consensus. Articles were classified based on the ISB features of height, geometry, material, and retention system.

RESULTS

Twenty articles were included. Among the reviewed studies, 11 investigations analyzed the influence of different ISB geometries, 1 study assessed the impact of ISB diameter, 4 studies investigated the effect of ISB splinting, 2 articles evaluated ISB height, and 2 studies focused on the effect of ISB material on scan accuracy. In addition, 8 studies involved ISBs fabricated with different materials (1- and 2-piece polyetheretherketone and 1-piece titanium ISBs), and all of the reviewed articles tested screw-retained ISBs, except for 3 in vitro studies.

CONCLUSIONS

The findings did not enable concrete conclusions regarding the optimal ISB design, whether there is a relationship between IOS technology and a specific ISB design, or the clinical condition that maximizes intraoral scanning accuracy. Research efforts are needed to identify the optimal ISB design and its possible relationship with the IOS selected for acquiring intraoral digital implant scans.

Influence of age, training, intraoral scanner, and software version on the scan accuracy of inexperienced operators

PURPOSE

To evaluate the effect of operator age on the scan accuracy (trueness and precision) of inexperienced operators when compared with experienced operators, and how training, intraoral scanner (IOS), and software version affect scan accuracy.

MATERIAL AND METHODS

Thirty-four operators were sorted into groups: G1 (operators <25 years old, no experience), G2 (operators >40 years old, no experience), and G3 (experienced IOS operators). They conducted partial-arch scans before and after a 4-session training with two IOSs (Trios 3 and True Definition) and two software versions. These scans were compared with the reference scans obtained from conventional impressions and a laboratory scanner (IScan D103i) to evaluate trueness (mean root mean square values) and precision (standard deviation of root mean square values) with a software program (Geomagic Control X). Kruskal-Wallis and post-hoc Dunn's tests were used to evaluate the effect of age on the scan accuracy of inexperienced groups when compared with experienced operators, while the effect of training, IOS, and software version on scan accuracy was evaluated with Wilcoxon or Mann-Whitney U tests (α = 0.05).

RESULTS

Before training, G1 and G2 scans had similar accuracy (p ≥ 0.065). After training, G1 scans had higher accuracy when IOS data was pooled and had higher precision with TD (p ≤ 0.004). Training increased the scan accuracy (p < 0.001), while newer software increased the trueness of inexperienced operator scans (p = 0.015).

CONCLUSIONS

Age affected the scan accuracy of inexperienced operators after training, indicating that extended training may be required for older operators. Training increased the scan accuracy, and newer software increased the trueness of inexperienced operator scans.

Accuracy of digitally coded healing abutments: A systematic review

The aim of this systematic review was to evaluate the in vitro accuracy of dental implant impressions taken using digitally coded healing abutments (CHAs) compared with impressions taken with conventional techniques (CI) and/or within the CHA group at varying degrees of angulations for multiple implant units. Two independent reviewers conducted a systematic electronic search in the MedLine, PubMed, Google Scholar, Cochrane Library, Web of Science, and Scopus databases. Some of the employed key terms, combined with the help of Boolean operators, were: "digitally coded healing abutments", "encode healing abutment", "dental implants", "impression accuracy", "digital impression", and "conventional impression". Publication dates ranged from January 2010 to November 2022. A total of 7 articles fulfilled the inclusion criteria: 6 studies compared the accuracy of CHA with conventional pick-up impression techniques, and one study only used CHAs at different angulations and heights to compare accuracy within the group. The results were divided into Group A (elastomeric impression of CHA) and Group B (CHA + Intraoral scanner). According to the results of this systematic review, elastomeric impression of CHA performed poorly when compared to CI for multiple implants, although an intraoral scan of CHA appears to be more accurate. Within the CHA group, the angulation and visible height of CHA play a significant role in impression accuracy. However, more studies are needed before CHA can be recommended for all non-parallel multiple implant-supported restorations.

Trueness and precision of combined healing abutment scan body system scans at different sites of maxilla after multiple repositioning of the scan body

OBJECTIVES

To evaluate the accuracy of the scans of the combined healing abutment-scan body (CHA-SB) system located at different sites of the maxilla when SBs are replaced in between each scan.

METHODS

Three SBs were seated into HAs located at the central incisor, first premolar, and first molar sites of a maxillary model inside a phantom head, and the model was scanned extraorally (CEREC Primescan SW 5.2). This procedure was repeated with new SBs until a total of 10 scans were performed. Standard tessellation language files of CHA-SBs at each implant location were isolated, transferred into analysis software (Geomagic Control X), and superimposed over the proprietary library files to analyze surface (root mean square), linear, and angular deviations. Trueness and precision were evaluated with one-way analysis of variance and Tukey tests. The correlation between surface and angular deviations was analyzed with Pearson's correlation (α=0.05).

RESULTS

Molar implant scans had the highest surface and angular deviations (P≤.006), while central incisor implant scans had higher precision (surface deviations) than premolar implant scans (P=.041). Premolar implant scans had higher accuracy than central incisor implant scans on the y-axis (P≤.029). Central incisor implant scans had the highest accuracy on the z-axis (P≤.018). A strong positive correlation was observed between surface and angular deviations (r = 0.864, P<.001).

CONCLUSION

Central incisor implant scans mostly had high accuracy and molar implant scans mostly had lower trueness. SBs were mostly positioned apically; however, the effect of SB replacement can be considered small as measured deviations were similar to those in previous studies and the precision of scans was high.

CLINICAL SIGNIFICANCE

Repositioning of scan bodies into healing abutments would be expected to result in similar single crown positioning regardless of the location of the implant, considering high scan precision with the healing abutment-scan body system. The duration of the chairside adjustments of crowns in the posterior maxilla may be longer than those in the anterior region.

In vitro scan accuracy and time efficiency in various implant-supported fixed partial denture situations

OBJECTIVES

To compare the accuracy and time efficiency of different digital workflows in 3 implant-supported fixed partial denture situations.

METHODS

Three partially edentulous maxillary models with 2 implants (Model 1: implants at lateral incisor sites; Model 2: implants at right canine and first molar sites; Model 3: implants at right first premolar and first molar sites) were digitized (ATOS Capsule 200MV120, n=1) for reference scans. Test scans were performed for direct (Primescan (DDW-P) and Trios 3 (DDW-T)) and indirect (IDW) digital workflows (n=14). For IDW, stone casts (type IV) were obtained from vinylsiloxanether impressions and digitized (S600 Arti). The scan/impression and post processing times were recorded. Reference and test scans were superimposed (GOM Inspect) to calculate 3D point, inter-implant distance, and angular deviations. Kruskal-Wallis and Mann-Whitney tests were used for trueness and precision analyses (α=.05).

RESULTS

Tested workflows affected trueness (P≤.030) and precision (P<.001) of scans (3D point, inter-implant distance, and angular deviations) within models. DDW-P had the highest accuracy (3D point deviations) for models 1 and 3 (P≤.046). IDW had the lowest accuracy for model 2 (P<.01). DDW-P had the highest accuracy (inter-implant distance deviations) for model 3 (P≤.048). Direct digital workflow mostly led to lower angular deviations (P≤.040), and higher precision for models 2 (mesiodistal direction) and 3 (P<.001). The time for direct digital workflow was shorter (P<.001), DDW-P being more efficient than DDW-T (P=.008).

CONCLUSION

Direct digital workflow was more accurate and efficient than indirect digital workflow in tested partial edentulism situations with 2 implants.

CLINICAL SIGNIFICANCE

Tested intraoral scanners can be recommended for accurate and efficient impressions of anterior and posterior 3- or 4-unit implant-supported fixed partial dentures.

Trueness and precision of combined healing abutment-scan body system depending on the scan pattern and implant location: an in-vitro study

OBJECTIVE

To test the effect of scan pattern and the location of the implant on the trueness and precision of implant scans when the combined healing abutment-scan body (CHA-SB) system is used.

MATERIAL AND METHODS

A partially edentulous maxillary model with CHA-SBs secured on implants at 3 different sites in the left quadrant (central incisor, first premolar, and first molar) was fabricated. The model was scanned with an industrial light scanner to generate a master reference model (MRM) file. An intraoral scanner (TRIOS 3) was used to perform the test scans (n=8) with 4 different scan patterns (SP1, SP2, SP3, and SP4) with an intraoral scanner. The test scans were superimposed over the MRM file with a metrology software to calculate the distance deviations of the CHA-SB system. Data were analyzed with a 2-way analysis of variance and Tukey's honestly significant difference tests for accuracy (α=.05).

RESULTS

Trueness (P=.001) and precision (P=.018) were significantly affected by the interaction between the scan pattern and implant location. The implant located at the central incisor site (56.7 ±35.9, 36.2 ±18.6) had higher trueness than that of located at the premolar site (94.1 ±20.4, 100.3 ±20) when SP2 (P=.037) and SP4 (P=.002) were used. The implant at the molar site (71.9 ±25.7, 147.2 ±49.7) had trueness either similar to (when SP2 was used, P≥.276) or lower than (when SP4 was used, P≤.024) those of others. Scans of the central incisor and premolar implants had the lowest trueness when scanned with SP1 (P≤.009), while the scans of molar implant showed higher trueness when performed by using SP2 and SP3 when compared with SP4 (P≤.005). When SP4 was used, the implant at the molar site had lower precision (43 ±18.9) than the implants located at the central incisor (14.1 ±11) and premolar sites (15.4 ±11.3) (P=.002). Scan patterns affected the scan precision of central incisor implant (P=.009), as SP4 (14.1 ±11) led to a higher precision than SP1 (47.7 ±27) (P=.006).

CONCLUSIONS

The scan accuracy of combined healing abutment-scan body system was affected by scan pattern and implant location. SP1, which involved palatal and rotational scans resulted in the lowest trueness for central incisor and premolar implants, while the scans of the central incisor implant showed the highest trueness among different sites when SP4 was used. However, the scan pattern and implant site had a minor effect on precision. Scan precision at different implant sites only differed when SP4 was used, which resulted in the lowest precision for molar implant.

Congruence between the meshes of a combined healing abutment-scan body system acquired with four different intraoral scanners and the corresponding library file: an in vitro analysis

OBJECTIVES

To investigate the congruence between the meshes of a combined healing abutment-scan body (CHA-SB) system acquired with four different intraoral scanners and the corresponding library file.

MATERIAL AND METHODS

A CHA-SB was fixed to an implant at the right first molar position in a dentate mandibular model and digitized by using 4 different intraoral scanners (IOSs) [TRIOS 3 (T3), Omnicam (OC), Primescan (PS), and Virtuo Vivo (VV)] (n=8) and an industrial grade optical scanner (ATOS Core 80) (n=1) to generate standard tessellation language (STL) files of the test scans (CHA-SB-STLs) and the master reference model scan (MRM-STL). A reverse engineering software (Studio Geomagic X) was used to superimpose the proprietary library file of the CHASB over the generated STL files. Root mean square (RMS) values representing the deviations between the library file and the superimposed STL files were statistically analyzed by using 1-way ANOVA (α=.05). Qualitative analysis of the deviations was performed by visual inspection.

RESULTS

Differences between the congruence of the library file and the CHA-SB scans among different IOSs were nonsignificant (F=1.619, df= 3, P = .207). The single best result was 29 ±28.9 µm for OC, 30.8 ±29.6 µm for VV, 35.6 ±35.5 µm for T3, and 39.5 ±39.2 µm for PS, which were all above the deviation value of the scan performed by using the industrial-grade scanner (23.2 ±23.2 µm).

CONCLUSION

The dimensional congruence between the library file and the standard tessellation language file of the combined healing abutment-scan body system scans was similar when intraoral scanners with different acquisition technologies were used to scan a model with an implant.

CLINICAL SIGNIFICANCE

Scans of the tested intraoral scanners may result in crowns with similar positional accuracy, given the similarities in congruence of their scans with the library file.

Effect of implant location and operator on the accuracy of implant scans using a combined healing abutment-scan body system

OBJECTIVES

To investigate the effect of implant location and operator on the accuracy of implant scans conducted with a combined healing abutment-scan body (CHA-SB) system.

MATERIAL AND METHODS

A CHA-SB system was fixed on implants at left central incisor, first premolar, and first molar sites in a dentate maxillary model. An industrial optical scanner (ATOS Core 80) was utilized to scan and generate a reference model (RM). The model was scanned by three operators (n = 8) using an intraoral scanner (TRIOS 3). A software (GOM Inspect) was used to superimpose IOS test scans over RM and calculations (distance and angular deviations) were carried out to evaluate the accuracy of the scans. Data were compared with a 2-way ANOVA and Tukey HSD tests were employed to resolve significant interactions for trueness and precision (α = .05).

RESULTS

Implant location affected the trueness (P ≤ .001) and the precision (P ≤ .020) (distance and angular deviations). The scans of the implant at the central incisor site had the highest trueness (distance and angular deviations) (P ≤ .016). The scans of the implant at molar site had the lowest precision (distance deviation data) (P ≤ .012). The scans of the implant at premolar site had lower precision (angular deviation data) than the scans of the implant at central incisor site (P = .016). Operators' effect on the accuracy of scans was not significant (P ≥  .051).

CONCLUSION

Implant location affected the scan accuracy of the combined healing abutment-scan body system. The scans of the implant at central incisor site had high trueness. The posterior the implant location, the lower was the precision of the scans. The accuracy of scans of different operators was similar.

CLINICAL SIGNIFICANCE

Higher deviations found in scans of posterior maxilla compared with those in the anterior region may require increased chairside adjustments when crowns are to be fabricated using the scans of the tested healing abutment-scan body system. However, clinical studies are necessary to corroborate the findings.

Accuracy of single implant scans with a combined healing abutment-scan body system and different intraoral scanners: AAn in vitro study

OBJECTIVE

The aim of the present study was to evaluate the accuracy of single implant scans with a combined healing abutment-scan body (CHA-SB) system using different intraoral scanners.

METHODS

A partially edentulous model with an implant was fabricated, and a CHA-SB system was secured on the implant. The model was scanned using an industrial-grade blue light scanner (ATOS Core 80) and a master reference model was generated (MRM). The model was also scanned with 4 different intraoral scanners (IOSs) [(Virtuo Vivo (VV), TRIOS 3 (T3), Omnicam (CO), and Primescan (PS)]. Test scans (n = 8) were superimposed over the MRM using the best fit algorithm (GOM Inspect 2018; GOM GmbH). After superimpositions, distance and angular deviations at selected areas on CHA-SB system were calculated. The data were analyzed with a 1-way ANOVA and Tukey HSD tests for trueness and precision (α=0.05).

RESULTS

The differences in trueness (distance deviations) among tested IOSs were nonsignificant (P=.652). VV presented the highest angular deviations (P ≤.031), and the angular deviations in other IOS scans were not found different (P ≥.378). The precision of distance deviation data was not significantly different among scanners (P=.052). For the precision of angular deviation data, significant differences were found among IOSs (P=.002). Compared with PS (P=.007) and T3 (P=.014), VV had significantly lower precision, which was not significantly different than that of CO (P=.815).

CONCLUSIONS

The accuracy (angular deviation) of scans of a combined healing abutment-scan body system on a single implant varied depending on the IOS. VirtuoVivo scans had the lowest accuracy in terms of angular deviations. When the distance deviation data were considered, scan accuracy of scanners was similar.

CLINICAL SIGNIFICANCE

A recently introduced combined healing abutment-scan body system combines the acquisition of both the implant and the soft tissue. When different intraoral scanners scan the combined healing abutment-scan body system, the scan accuracy may vary.

The accuracy of single implant scans with a healing abutment-scanpeg system compared with the scans of a scanbody and conventional impressions: An in vitro study

PURPOSE

To compare the accuracy of polyvinylsiloxane (PVS) impressions and intraoral scans when a healing abutment-scanpeg system (HASP) or a conventional scanbody (CSB) was used on a single implant.

MATERIALS AND METHODS

A maxillary model with an implant (4.0 × 11 mm) (Neoss) and a CSB or an HASP (Neoss) was scanned by using a laboratory scanner (Ceramill Map 600; Amann Girrbach) (reference scans) and an intraoral scanner (Trios 3) (n = 10). PVS open-tray impressions were also made and stone casts of the model with a CSB were digitized with the laboratory scanner. Intraoral scanner and cast scans were superimposed to their reference scans. On superimposed scans, points were selected on HASP and CSB to calculate distance deviations (at points 1-4) and angular deviations (at points 5 and 6 on CSB and PVS, and 5-8 on HASP) between scans (trueness), and their variation (precision). The deviation data was analyzed with ANOVA and pairwise comparisons (trueness) with Tukey's adjustment, and F-tests (precision).

RESULTS

At point 1, PVS had lower trueness than CSB (difference in means (DIMs) = 0.184 mm, p = 0.006) and HASP (DIMs = 0.122 mm, p = 0.042). At point 3, CSB had higher trueness than HASP (DIMs = 0.134 mm, p = 0.001). Angular deviations with PVS were higher than with CSB (DIMs = 0.6°, p = 0.013) and HASP (DIMs = 0.7°, p = 0.005). CSB had higher precision than PVS (p < 0.05). HASP had higher precision than PVS for distance (Point 1)(p < 0.001) and angular deviations (p < 0.05). Deviation differences within the HASP parts were not significant.

CONCLUSION

The accuracy of intraoral scans and PVS impressions of an implant was similar.

CLINICAL RELEVANCE

The combined healing abutment-scanpeg system and the conventional scanbody can be recommended for scans of anterior single implants with the intraoral scanner used.