Digital denture with mucostatic base and functional borders: A cast-free digital technique.

Digital complete dentures fabricated using a mucostatic impression, like intraoral scans, are desirable for their beneficial effect on long-term residual ridge stability but may have less retention than those fabricated with a mucocompressive impression. Border molding procedure may improve initial retention, thus favoring adaptation to new dentures, especially in cases where neuromuscular dysfunctions may diminish the patient's ability to cope with adapting to existing motor patterns or learn new ones. However, a mucocompressive impression may cause higher residual ridge resorption, thus resulting in a retention decrease over time. A desirable combination would be a digital denture with a mucostatic intaglio surface obtained from intraoral scans and functional borders. A cast-free digital workflow for that is demonstrated in this technical report.

Cast-free fabrication of a digital removable partial denture with a polyetheretherketone framework.

Digital workflows for removable partial dentures have enabled new machinable framework materials, including polyetheretherketone (PEEK). In addition, all denture components can be designed and manufactured digitally. Nonetheless, physical casts are still required for assembly of the components. The adoption of a cast-free fabrication procedure may enhance benefits, including a reduced number of procedures, faster processing, and reduced material waste. The purpose of this technical report was to demonstrate a workflow for the fabrication of a removable partial denture with a PEEK framework, milled teeth, and milled flanges, which uses intraoral scanning and no physical casts.

Intaglio surface trueness of milled and 3D-printed digital maxillary and mandibular dentures: A clinical study.

STATEMENT OF PROBLEM: While the dimensional accuracy of the intaglio surface of a removable complete denture is key to its adaptation, comfort, and clinical performance, information on the ability of milling and 3D-printing workflows to accurately reproduce this surface is lacking. PURPOSE: The purpose of this clinical study was to compare the trueness of the intaglio surface of milled and 3D-printed removable complete digital dentures. MATERIAL AND METHODS: Intraoral scans were obtained from 14 participants for a total of 20 edentulous arches. Ten maxillary and 10 mandibular denture bases were then designed and fabricated with a completely digital workflow, both with milling and 3D-printing. Fabricated dentures were digitized with the same intraoral scanner used to obtain intraoral digital scans of the edentulous arches. Standard tessellation language (STL) files of the printed and milled denture bases were used for 3D analysis and comparisons with the STL file of the corresponding designed denture base. Specifically, a reverse engineering software program was used to trim and extract intaglio surfaces, align them, and measure their global mean 3D distance. In order to evaluate the homogeneity of production accuracy of each manufacturing process, the intaglio surfaces were also divided into several regions of interest and the corresponding 3D distances measured. Within- and between-group differences and maxillary and mandibular dentures differences were assessed with parametric and nonparametric tests (α=.05). RESULTS: Milling showed a global better trueness of the entire intaglio surface (-0.002 mm) than 3D-printing (0.018 mm), both for the whole data set (P<.001) and for maxillary (P=.032) or mandibular (P=.049) denture base subgroups. Within each fabrication technology, maxillary (P<.11) and mandibular dentures (P=.2) showed no significant difference in trueness. Measured deviations were significantly different from zero for the 3D-printed dentures (P<.001), but not for the milled dentures (P=.487). Additionally, for milled dentures, no significant difference in trueness was found among the 11 regions of interest identified for the maxillary dentures (P=.085) and the 13 regions of interest for the mandibular dentures (P=.211). Conversely, 3D-printing showed significant variations in trueness among the same zones of interest, both in maxillary (P<.001) and mandibular (P=.004) dentures. CONCLUSIONS: Within the limits of the manufacturing methodologies used for complete dentures, milling can provide a slightly better trueness of the intaglio surface than 3D-printing, with less variation across several zones of interest. However, given the magnitude of such differences, they may be reasonably considered to be of limited, if any, clinical significance.

Assessment of distortion of intraoral scans of edentulous mandibular arch made with a 2-step scanning strategy: A clinical study.

STATEMENT OF PROBLEM: Manufacturers of several intraoral scanners have recommended a 2-step strategy for scanning the edentulous mandible. The 2-step technique requires scanning one side first and then moving to the other side. However, whether inconsistency in stitching occurs that results in loss of accuracy or distortion is unclear. PURPOSE: The purpose of this clinical study was to measure the potential distortion of intraoral scans of edentulous mandibular arches made with a 2-step scanning strategy and to assess their differences with conventional impressions. MATERIAL AND METHODS: Twenty mandibular edentulous arches were scanned by 1 investigator with an intraoral scanner using a 2-step scanning strategy, and a corresponding polysulfide conventional impression was obtained. The conventional impression was then immediately scanned with the same intraoral scanner. The obtained standard tessellation language (STL) files were superimposed with a surface-matching software program. After a preliminary alignment, the STL meshes were trimmed and reoriented; then, the final alignment was carried out and meshes moved to a metrology software program where their mean distance was measured. In addition, a surface curve (SIOS) was traced on the intraoral scan from the right to left retromolar pad along the residual ridge and automatically projected onto to the conventional impression scan to obtain a new curve (SC). The mean distance between SIOS and SC was measured and recorded as an indicator of the distortion by considering the X-, Y-, and Z-axes and the overall 3-dimensional (3D) deviation. The analysis was performed for the full curve length and after dividing it into 6 regions of interest. Univariate and multivariate statistical analyses were used to investigate the significance of the extent of the mean 3D distance, as well as the effects of measurement positions (side and region) between and within patients on differences along the X-, Y-, and Z-axes (α=.05). RESULTS: The mean (-0.08 mm; standard error: 0.025) 3D distance between the intraoral scan and conventional impression was significantly different from zero (P=.003). No significant effect of the factor "side" was found by using generalized estimated equation models for the X-, Y-, and Z-axes, and global 3D deviations between SIOS and SC (P>.05), which appeared to exclude distortion. Conversely, a significant effect was found for the factor "region" (P<.05), with no significant differences (P>.05) between corresponding regions on the 2 sides. CONCLUSIONS: Intraoral scans of the edentulous mandibular arch made in a 2-step procedure did not exhibit significant distortion in comparison with conventional impressions.

Accuracy of trial complete dentures fabricated by using fused deposition modeling 3-dimensional printing: An in vitro study.

STATEMENT OF PROBLEM: Three-dimensional (3D) printing technologies commonly used for trial complete dentures use photopolymerizing resins. Although effective, some clinical, process-related, and practical issues associated with them are still unclear. The option of using alternative printing technologies may help in overcoming limitations. PURPOSE: The purpose of this in vitro study was to evaluate the trueness of trial dentures fabricated by using 3D-printing fused deposition modeling (FDM). MATERIAL AND METHODS: Ten maxillary and 10 mandibular digital complete trial dentures designed from intraoral scans were fabricated from polylactic acid by using a FDM 3D-printer. Each denture was scanned, and the scans were compared with the digital file of the designed denture by means of a surface-matching software program. The mean distance (both signed and absolute) was measured and recorded for the intaglio surface, as well as for the entire denture surface. Statistical analysis was performed to investigate the significance of the extent of measured distances, as well as differences between intaglio and global deviations; subgroup analysis for arch type was also performed (α=.05). RESULTS: Mean values of the intaglio distance were not significantly different from zero (P=.223). The manufacturing accuracy of the intaglio surface was higher than that measured for the entire denture (P<.001), confirmed both by the averaged signed (0 mm and -0.028 mm, respectively) and the absolute mean deviations (0.06 mm and 0.08 mm, respectively). No significant differences were found between maxillary and mandibular trial dentures. CONCLUSIONS: 3D-printing may constitute a valid and practical option for accurate and affordable digital trial dentures.

Assessment of tooth displacement during the cast-free digital processing of milled dentures.

STATEMENT OF PROBLEM: Denture tooth displacement may have a significant impact on denture occlusion. This aspect has seldom been investigated, especially for digital denture processing techniques. PURPOSE: The purpose of this clinical study was to evaluate the accuracy of tooth position with milled digital dentures processed without physical casts. MATERIAL AND METHODS: Ten maxillary and 10 mandibular dentures designed from intraoral scans, milled, and processed without physical casts were investigated. The standard tessellation language (STL) files of the digitally designed dentures were compared with the scan of the dentures after processing (milling the denture base, milling teeth in a complete arch, and then bonding teeth into the base). The STL files were superimposed by using a surface-matching software program. After a preliminary alignment, the STL meshes were trimmed and reoriented; then, the final alignment was carried out by using the cameo surface. Six reference points (the mesiobuccal cusp on the most distal molar, the canine cusp, the middle of the incisal edge of the central incisor on both the left and the right side) were selected to measure tooth displacements along the X-, Y-, and Z-axes, corresponding (from the preliminary reorientation) to anteroposterior, mediolateral, and occlusal displacement, respectively. Tooth position accuracy was assessed by using median and interquartile range values. Univariate and multivariate statistical analyses were used to investigate the significance of the extent of displacements, as well as differences among displacement directions, reference teeth, side, and denture arch type (α=.05). RESULTS: Only the median (0.2 mm; interquartile range: 0.27 mm) occlusal displacement was significantly different from zero. A generalized estimated equation model addressing occlusal displacement as a dependent variable showed no significant effect of tooth type, side, or denture arch type, either alone or in combination. CONCLUSIONS: The tooth position of both maxillary and mandibular milled digital dentures processed without physical casts was accurate in the anteroposterior and mediolateral directions. Occlusal displacement seemed to be within the range of clinical acceptability; its consistency throughout the arch allowed optimization or compensation at the design or manufacturing step.

Three Dimensional Printed Surgical Guides: Effect of Time on Dimensional Stability.

PURPOSE: To analyze, in vitro, the dimensional stability over time of 3D-printed surgical guides. MATERIALS AND METHODS: Ten surgical guides, manufactured by digital light processing 3D-printing technology, were scanned immediately after post-processing and then after 5, 10, 15, and 20 days. The corresponding standard tessellation language (STL) files were used for comparison with the reference CAD project. Mean absolute deviation (MAD) of the intaglio surface, axial, and linear deviations of the sleeves' housings were measured. Generalized estimated equations models (α = 0.05) were used to investigate the effect of time. RESULTS: MAD of the teeth intaglio surface showed less variation (minimum: 0.002, maximum: 0.014 mm) than that of the mucosa (minimum: 0.026, maximum: 0.074 mm). Axial variations of the sleeves' housings on the sagittal (minimum: -0.008°, maximum: -0.577°) and frontal plane (minimum: -0.193°, maximum: 0.525°) changed with similar patterns, but opposite trends (decreasing for the former). Linear deviations of center points of the sleeves' housings had a shifting (minimum: -0.074, maximum: 0.02 mm) pattern with a decreasing tendency. Time after processing had a significant effect, either alone or nested with guides volume, on all outcomes of interest, except for MAD of the mucosa intaglio surface (p < 0.001), which was significantly affected only by the time-volume nested effect (p = 0.012). CONCLUSIONS: Within the limitations of the experimental design, postmanufacturing dimensional variations of surgical guides were statistically significant. Although limited, they are an additional source of variability affecting the overall accuracy of computer-guided surgery. As such, they should be addressed by further research.

Comparative cost-analysis for removable complete dentures fabricated with conventional, partial, and complete digital workflows.

STATEMENT OF PROBLEM: Comparative cost-analysis related to different manufacturing workflows for removable complete denture fabrication is seldom performed before the adoption of a new technology. PURPOSE: The purpose of this study was to compare the clinical and laboratory costs of removable complete dentures fabricated with a conventional (workflow C), a partial digital (workflow M), and a complete digital (workflow D) workflow and to calculate the break-even points for the implementation of digital technologies in complete denture fabrication. MATERIAL AND METHODS: Clinical and laboratory costs for each of the investigated workflows and the manufacturing options related to denture base and denture teeth fabrication were collected from 10 private Italian dental laboratories and clinics. The selected variables included the clinical and laboratory manufacturing time needed to complete each workflow (opportunity cost); costs for materials, labor, packaging, and shipping; and capital and fixed costs for software and hardware, including maintenance fees. The effect of manufacturing workflows and their options on the outcomes of interest was investigated by using generalized estimated equations models (α=.05). Cost minimization and sensitivity analysis were also performed, and break-even points were calculated for the equipment capital costs related to the implementation of workflows M and D. RESULTS: From a laboratory standpoint, workflows M and D and related manufacturing options significantly (P<.001) reduced manufacturing time (5.90 to 6.95 hours and 6.30 to 7.35 hours, respectively), and therefore the opportunity cost of each denture compared with workflow C. Workflow M allowed variable costs savings between 81 and 169 USD, while workflow D allowed for an additional saving of 34 USD. The sensitivity analysis showed that the break-even point related to the capital investment for the equipment needed to implement workflows M and D could be reached, depending on the manufacturing options adopted, between 170 and 933 dentures for workflow M and between 73 and 534 dentures for workflow D. From a clinical standpoint, workflows C and M were almost identical. Conversely, workflow D, which included intraoral scanning, required 1 fewer appointment, saving 0.6 hours of chairside time and about 14 USD for materials compared with M. CONCLUSIONS: Digital workflows (partial and complete digital workflows) were more efficient and cost-effective than the conventional method of fabricating removable complete dentures, with workflow D showing the lowest opportunity and variable costs and break-even point. Savings increased when stock denture teeth were replaced with milled denture teeth and still further with the adoption of 3-dimensionally (3D) printed denture teeth. Milling equipment and materials for denture base fabrication were more expensive than those for 3D-printing. Milling monobloc dentures reduced opportunity and labor costs but increased material cost.

Removable Partial Dentures with Polyetheretherketone Framework: The Influence on Residual Ridge Stability.

PURPOSE: To provide, in a clinical case-control study, 1-year data on edentulous residual ridge dimensional changes for patients wearing removable partial dentures (RPD) with Polyetheretherketone (PEEK) framework, fabricated with a digital workflow, and a control group of untreated patients. MATERIALS AND METHODS: Ten patients were treated with PEEK RPD, and six controls were studied. Intraoral scans at baseline (T0) and after a median period of 1 year (T1) were superimposed, trimmed, and reoriented (T0r and T1r), moved to a metrology software, and realigned. A curve (C0) was then traced on T0r, along the residual ridge crest; its projection (C1) on T1r was obtained. The mean distance C0-C1 was the dependent variable of interest and represented the 1-year changes in the height of the edentulous ridge. In addition, mean 3D distance between T0 and T1 at each edentulous area was measured. Differences in these outcomes measured between RPD treated and control groups were statistically assessed. RESULTS: Twenty-six and 14 edentulous areas were investigated in the RPD treated and control groups, respectively. No significant differences were observed for potentially confounding variables, such as median follow-up time (12.5 vs. 13 months, respectively), the alignment accuracy between T0r and T1r (0.01 mm vs. 0 mm, respectively), the median number of remaining teeth (6 vs. 8.5, respectively), and the median length of edentulous areas (25.5 mm vs. 22.8 mm, respectively). For the outcomes of interest, no statistically significant difference was seen in the mean distance between C0 and C1 (i.e., changes in residual ridge height: -0.39 ± 0.52 mm vs. -0.52 ± 0.54 mm, respectively) or in the mean 3D distance at corresponding points of the denture bearing areas (-0.3 ± 0.46 mm vs. -0.4 ± 0.35, respectively). CONCLUSIONS: Although 1 year is a relatively short observation period, this clinical study shows that there are no short-term differences in edentulous residual ridge height and overall dimensions between patients wearing PEEK RPD, fabricated with a digital workflow, and controls without an RPD.

Trueness of Intaglio Surface of Milled Digital Dentures Designed from Intraoral Scans.

PURPOSE: To asses trueness of the intaglio surface of milled dentures fabricated according to a fully digital protocol starting from intraoral scans in a clinical study by means of 3-dimensional (3D) digital analysis. MATERIALS AND METHODS: Ten maxillary and 10 mandibular dentures, designed from intraoral scans and milled in-house, were studied. Intraoral scans were compared with the scans of intaglio surface of milled dentures. To this end, they were aligned, trimmed and used in a metrology software to measure their mean 3D distance, absolute mean deviation, and other parameters. Measured differences for all parameters were statistically investigated. Subgroup analysis for the maxillary and mandibular dentures was performed using independent samples t-test or, in case of non-normal distribution, by means of Mann-Whitney test. RESULTS: Using a mean of 24.9 ±2.8 measurement points/mm2 , a mean 3D distance of 0.0006 ±0.007 mm between intraoral scans and the scans of the intaglio surface of milled dentures was measured. The corresponding absolute mean deviation was 0.055 ±0.032 for maxillary dentures and 0.061 ±0.016 for mandibular dentures; such a difference between arches was statistically significant (p = 0.035). CONCLUSIONS: Milled dentures fabricated using a fully digital protocol and intraoral scans have accurate intaglio surfaces. It is reasonable to assume that they may achieve an adequate fit.

Digital dentures: A protocol based on intraoral scans.

The use of intraoral scans for complete denture fabrication may improve patient comfort, clinic ergonomics, and laboratory efficiency. Techniques have been reported regarding specific tasks related to the use of intraoral scans for digital dentures, but an integrated workflow is still lacking. This technique article describes a complete workflow for the digital fabrication of complete dentures, starting from intraoral scans and with no physical casts; in addition, the presented workflow integrates partial and complete face scans in the design process to optimize tooth arrangement.

Integrating intraoral, perioral, and facial scans into the design of digital dentures.

Digital technologies offer the opportunity to integrate facial scans into the design of digital dentures and provide a beneficial 3D preview and simulation of the tooth arrangement for both treatment planning and communication. The presented technique describes a procedure of merging and aligning the intraoral scans of edentulous arches, the scans of the perioral area, and the scan of the nose made by using an intraoral scanner, as well as facial scans made by using a mobile phone. Thus, a digital patient can be obtained and used to optimize individual tooth arrangement during the design of the digital denture.

Intraoral scans of edentulous arches for denture design in a single procedure.

Digital denture design requires anatomic information, an accurate maxillomandibular relationship, and parameters to guide tooth arrangement. Capturing all these data by intraoral scanning makes their immediate digitization, integration, and transfer to the computer-aided design workflow possible, which can be started without an additional procedure. The presented technique describes the digital workflow to automatically align intraoral scans of completely or partially edentulous maxillary and mandibular arches according to the maxillomandibular relationships registered in digitally designed occlusion rims adapted on the patient.

Three-dimensional differences between intraoral scans and conventional impressions of edentulous jaws: A clinical study.

STATEMENT OF PROBLEM: Using intraoral scans for removable dentures has been questioned because of a suggested lack of accuracy. However, data regarding the accuracy of digital intraoral complete-arch scans are sparse, present some methodological issues, and mostly come from in vitro studies on dentate casts, which are very different from edentulous arches. PURPOSE: The purpose of this clinical study was to evaluate 3D differences between intraoral scans (IOS) and conventional impressions of edentulous arches by means of digital analysis. MATERIAL AND METHODS: Ten maxillary and 10 mandibular edentulous arches were investigated. For each of them, IOS was performed, and a custom tray was digitally designed based on these scans. Trays were built by using a 3D printer and used to make a conventional impression with a polysulfide impression material. The conventional impression was scanned immediately by using the same intraoral scanner and by the same dentist. Standard tessellation language (STL) files of IOS and the scans of the corresponding conventional impressions (CIS) were superimposed with a 2-phase best-fit alignment in a reverse engineering software program. The corresponding full-scan, 3D mean distance was measured. This procedure was repeated after trimming the IOS and CIS to eliminate peripheral areas not present in both files, as well as nonmatching areas caused by practical aspects related to obtaining the IOS (mobile tissue stretching) and the conventional impressions (mobile tissue compression and folding at the margin of impression), which could have impaired alignment and, consequently, measurement accuracy. The mean distance between the full and trimmed IOS and CIS was statistically investigated, and subgroup analysis was performed for the maxillary and mandibular arches. The statistical significance of the differences between the 2 impression methods was also investigated. RESULTS: The full-scan mean distance between the IOS and CIS (-0.19 ±0.18 mm) was significantly different from that of the trimmed scan mean distance (-0.02 ±0.05 mm), with no significant differences for maxillary and mandibular arches. The differences between the IOS and CIS were statistically significant for full scans; they were not significant for trimmed scans, except for the maxillary subgroup. CONCLUSIONS: The mean distance between the IOS and CIS may be significantly different if they are not properly superimposed. The mean distance (-0.02 ±0.05 mm) between the IOS and CIS falls within the range of mucosa resilience. Thus, 3D differences between the IOS and CIS can be attributed to the different physics behind the 2 impression methods and not to defects in accuracy of one method compared with the other. The size of the measured difference between the 2 impression methods was not statistically significant and was not clinically significant for removable denture fabrication.

Intraoral Scans Alignment in Single Edentulous Arch Cases.

Using intraoral scans for removable denture fabrication requires proper alignment according to maxillo-mandibular relationships. The presented technique combines intraoral and extraoral scanning of the occlusion rim to obtain intraoral scan alignment and the transfer of all information for tooth arrangement to the digital workflow. The technique was developed for single edentulous arch cases and is particularly indicated for the edentulous mandible; nonetheless, it can also be used for the maxilla if a full-size occlusion rim is required for optimal stability.

Alignment of intraoral scans and registration of maxillo-mandibular relationships for the edentulous maxillary arch.

One of the main issues in using intraoral scans for the fabrication of removable dentures is that scans need to be aligned to each other. The workflow presented provides aligned intraoral scans of the arches and of the occlusion rim incorporating maxillo-mandibular relationships and information for tooth arrangement in a single procedure. Thus, after intraoral scanning, the clinician can proceed directly with the denture design.

Digital versus conventional workflow for the fabrication of multiunit fixed prostheses: A systematic review and meta-analysis of vertical marginal fit in controlled in vitro studies.

STATEMENT OF PROBLEM: Limited evidence is available for the marginal fit of multiunit fixed dental prostheses (MFDPs) fabricated with digital technologies compared with those fabricated with conventional techniques. PURPOSE: The purpose of this systematic review and meta-analysis was to answer the following question: Does digital workflow for the fabrication of tooth-supported or implant-supported MFDPs provide better marginal fit than the conventional workflow? MATERIAL AND METHODS: PubMed, SCOPUS, EBSCO, and Web of Science databases were searched for controlled in vitro studies addressing direct comparison of the fit of MFDPs produced with digital or conventional workflows and excluding studies addressing interim restorations, MFDPs on mixed abutments (teeth and implants), or studies in which reproduction of the basic master cast was performed in 1 group. Vertical and horizontal marginal fit were the primary outcomes; meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, with subgroup analysis for tooth- or implant-supported MFDPs. RESULTS: Four studies published between 2011 and 2015 met the inclusion criteria and were included in the review. They investigated 3-unit partial fixed dental prostheses, exhibited a high degree of heterogeneity, and reported data only regarding vertical marginal fit. MFDPs fabricated with digital techniques presented a nominally higher vertical marginal discrepancy than those fabricated with the conventional technique, but the mean difference (MD) (19.8 µm, 95% confidence interval [CI]: -12.1; 51.7) has no statistical significance. The same is also applicable to subgroup analysis for a tooth-supported (MD=45.8 µm, 95% CI: -45.4; 137.0) or implant-supported (MD=14.7 µm, 95% CI: -38.6; 68.1) MFDP. CONCLUSIONS: Digital technologies offer a reliable alternative to conventional techniques for the fabrication of tooth- or implant-supported 3-unit fixed partial dentures; additional studies with up-to-date technologies and for prostheses with more than 3 units are recommended to provide stronger evidence.

Swallowing and Temporomandibular Disorders in Adults.

INTRODUCTION: Temporomandibular disease (TMD) etiology is multifactorial and is related to many perpetuating, predisposing, and initiating factors. The daytime parafunctions may have an important role in TMD pathogenesis. The most frequent parafunctions analyzed were the static parafunction (ie, clenching) and the dynamic parafunction (ie, grinding). In the present paper, the authors evaluated the swallowing (an oral function/parafunction) with the surface electromyography in patients with TMD. MATERIALS AND METHODS: Twenty patients with TMD problems (nonhealthy patients, NHP) (mean age: 33 ±â€Š1.994; 8 men and 12 women) and 20 healthy matched subjects (HP) (34.4 ±â€Š2.782; 6 men and 14 women) were selected and examined. On each patient, an 8-channel surface electromyography was done during saliva swallowing. RESULTS: Nonhealthy patients presented higher masseter and temporalis activation (P < 0.05) and an unbalancing of temporalis and submental muscles activation (P < 0.05) than the HP. DISCUSSION: Nonhealthy patients presented a time of swallow higher than HP (P < 0.001). Nonhealthy patients presented a higher muscles activation and time of swallow than HP and a decrease of muscles balancing activation.

Surgical guides for dental implants: Measurement of the accuracy using a freeware metrology software program.

PURPOSE: Manufacturing-related inaccuracies of surgical guides for static computer-aided implant surgery may contribute to the overall potential error in the obtained implant position. Measuring such inaccuracies before surgery may provide quality control assessment and improve the safety and outcomes of guided implant surgery. This technical report demonstrates a workflow to measure the accuracy of a surgical guide (at the intaglio surface and sleeve housing) using a freeware metrology software program. METHODS: The scan of a milled surgical guide was aligned to and compared with its reference computer-aided design model using a freeware metrology software program (GOM Inspect suite; GOM GmbH). The trueness of the internal surface of the surgical guide was measured as an indicator of adaptation to the supporting tissues. Additionally, some features were constructed to extract the plane at the sleeve entrance and sleeve axis and to set a local coordinate system on them. Linear and angular deviations between the planned and obtained sleeve axes were measured using this system. Such measurements, together with additional known data (sleeve offset and the planned implant length), allowed the estimation of linear errors in implant position at both the implant platform and apex by applying common geometric formulas, based on the assumption that all other sources of error in implant position could be effectively controlled during the surgical procedure. CONCLUSIONS: The proposed digital technique is a cost-effective approach for quality control of the inaccuracies of a surgical guide and predicts the related potential error in implant position.