Patient outcomes and procedure working time for digital versus conventional impressions: A systematic review

Intraoral Scanning Evaluation of Maxillary Arch Changes after Modified Sommerlad Palatoplasty for around Three Years

BACKGROUND

The purpose of this study was to investigate dental arch changes after modified Sommerlad palatoplasty in patients with cleft palate by intraoral scanning technique in children with early deciduous dentition.

METHODS

This study included 60 patients with nonsyndromic unilateral complete cleft lip with palate or cleft palate only treated by modified Sommerlad palatoplasty without relaxed excision before 18 months of age and 95 healthy controls without cleft. Three-dimensional images of the maxillary dental arches of all participants at age 3 to 4 years were obtained by intraoral scanning technique. Seven parameters (anterior dental arch width, middle dental arch width, posterior dental arch width, anterior palatal arch width, posterior palatal arch width, anterior dental arch length, and entire dental arch length) were measured.

RESULTS

Compared with the male group, the posterior palatal arch width distance of controls in the female group decreased significantly ( P = 0.039), and the middle dental arch width, posterior dental arch width, and posterior palatal arch width distance of female patients decreased ( P = 0.013, P = 0.002, P = 0.005, respectively). The anterior dental arch length and entire dental arch length distance of children in the unilateral complete cleft lip with palate group was shorter than those of children with cleft palate only ( P < 0.0001, P < 0.0001, respectively). The patient group showed decreased distance of anterior dental arch width, anterior palatal arch width, anterior dental arch length, and entire dental arch length, and increased distance of posterior dental arch width and posterior palatal arch width compared with the control group ( P = 0.0002, P = 0.002, P < 0.0001, P < 0.0001, P = 0.007, P = 0.027, respectively).

CONCLUSION

The results indicated that the modified palatoplasty group showed no growth inhibition in the middle or posterior dental arch width, or palatal arch width, but slight but significant inhibition in the length of the anterior and entire dental arch.

CLINICAL QUESTION/LEVEL OF EVIDNCE

Therapeutic, IV.

Evaluation of the accuracy of seven intraoral scanners for the full dentate and partially edentulous complete-arch mandibular casts: An in vitro comparison

Statement of problem

Intraoral scanners (IOSs) are widely used in dentistry, providing high accuracy in short-range scanning. Nevertheless, when scanning the full dental arch, it remains a challenge. Furthermore, there is a lack of studies reporting the differences in scan accuracy between dental arches with large-span mucosal areas and fully dentate casts or optimal IOS selection for different dental statuses.

Purpose

This study aimed to evaluate the accuracy and scanning time of different IOSs for full dentate (FD) and partially edentulous (PE) casts with missing teeth in the #34-#44 range and to determine the IOSs with the optimal clinical adaptability and scanning accuracy for different complete-arch casts.

Material and methods

Reference scans of two complete-arch (FD and PE) casts were obtained using a laboratory scanner (Ceramill Map 600). Subsequently, the same casts were scanned ten times each by seven IOSs (3Shape Trios 3, CS3600, Planmeca Emerald, iTero Element 5D, Medit i500, BAMBOO B1, and Shining Aoralscan 3), and the scanning time was recorded. The test data were superimposed on the reference scans for the selected areas, and three-dimensional deviations between the reference and test casts (trueness), and between test casts (precision) were determined using reverse engineering software (Geomagic Wrap). The dataset was analyzed using a two-factor analysis of variance with post-hoc Bonferroni tests.

Results

Two-factor analysis of variance revealed significant differences in accuracy and scanning time for different casts (P < 0.001) and IOSs (P < 0.001). For the FD cast, the i500 (0.35 ± 0.11 mm trueness) and CS3600 (0.23 ± 0.12 mm precision) performed worse than the remaining scanners. For the PE cast, the BAMBOO B1(0.89 ± 0.58 mm trueness; 0.88 ± 0.48 mm precision) performed worse than the remaining scanners. There were no differences in the accuracy of scanning between the Element 5D and Emerald for both cast types. However, the scanning time differed significantly between the different IOSs (P < 0.001). Regardless of the cast type, the fastest and slowest scans were performed by the Trios3 and CS3600 scanners respectively.

Conclusions

The accuracy and scanning time differed between the different IOSs and types of complete-arch casts.

Accuracy of edentulous full-arch implant impression: An in vitro comparison between conventional impression, intraoral scan with and without splinting, and photogrammetry

OBJECTIVES

The purpose of this in vitro study was to compare the trueness and precision of complete arch implant impressions using conventional impression, intraoral scanning with and without splinting, and stereophotogrammetry.

MATERIALS AND METHODS

An edentulous model with six implants was used in this study. Four implant impression techniques were compared: the conventional impression (CI), intraoral scanning (IOS) without splinting, intraoral scanning with splinting (MIOS), and stereophotogrammetry (SPG). An industrial blue light scanner was used to generate the baseline scan from the model. The CI was captured with a laboratory scanner. The reference best-fit method was then applied in the computer-aided design (CAD) software to compute the three-dimensional, angular, and linear discrepancies among the four impression techniques. The root mean square (RMS) 3D discrepancies in trueness and precision between the four impression groups were analyzed with a Kruskal-Wallis test. Trueness and precision between single analogs were assessed using generalized estimating equations.

RESULTS

Significant differences in the overall trueness (p = .017) and precision (p < .001) were observed across four impression groups. The SPG group exhibited significantly smaller RMS 3D deviations than the CI, IOS, and MIOS groups (p < .05), with no significant difference detected among the latter three groups (p > .05).

CONCLUSIONS

Stereophotogrammetry showed superior trueness and precision, meeting misfit thresholds for implant-supported complete arch prostheses. Intraoral scanning, while accurate like conventional impressions, exhibited cross-arch angular and linear deviations. Adding a splint to the scan body did not improve intraoral scanning accuracy.

Evaluation of Three-Dimensional Digital Models Formulated From Direct Intra-oral Scanning of Dental Arches in Comparison With Extra-oral Scanning of Poured Dental Models in Terms of Dimensional Accuracy and Reliability

BACKGROUND

The study's objective was to assess the dimensional accuracy and reliability of dental digital models prepared by direct intraoral scanning and indirect scanning of the plaster models compared to the plaster models as the gold standard.

MATERIALS AND METHODS

This study included 20 patients. Nine had a class I malocclusion, seven had a class II malocclusion, and four had a class III malocclusion. Intraoral scanning was done for the upper and lower arches of all the patients enrolled in this study using an intraoral scanner (i700; Medit, Seoul, Korea). The next step was preparing the plaster model for the control group. Addition-silicone impressions were taken for each patient's arches. The impressions were poured according to American Board of Orthodontics (ABO) standards. Finally, the digital models of the indirect scanning group were prepared using a 3D desktop scanner (T710; Medit). In total, 26 measurements were made on the plaster and digital models. Paired t-tests were used to test for significant differences between the studied groups. The reliability of the studied techniques was tested using intraclass correlation coefficients (ICCs). Because of the multiple comparisons, the ɑ level was adjusted and set at 0.002.

RESULTS

No significant differences were found between the intraoral scanning group (20 patients) and the plaster models group (20 patients; P>0.002). The ICCs ranged from 0.814 to 0.993, indicating excellent agreement between the direct digital and traditional plaster models. There were no significant differences between the digital and original plaster models (P>0.002). ICCs ranged from 0.834 to 0.995, indicating excellent agreement between the indirect digital and original plaster models. No significant differences were detected between the direct and indirect digital models (P>0.002). ICCs ranged between 0.813 and 0.999, indicating excellent agreement between direct and indirect digital models.

CONCLUSION

Both direct and indirect scanning techniques are accurate and reliable for digital model preparation and can be considered an alternative to traditional plaster models used in clinical orthodontics diagnostic applications. The intraoral scanning technique can be considered a valid alternative for indirect scanning of the plaster models to prepare digital working models during the digital design and fabrication of orthodontic appliances such as clear aligners.

Effect of artificial landmarks of the prefabricated auxiliary devices located at different arch positions on the accuracy of complete-arch edentulous digital implant scanning: An in-vitro study

OBJECTIVES

To examine the effect of artificial landmarks of prefabricated auxiliary devices (PAD) located at different arch positions on the accuracy of complete-arch edentulous digital implant scanning.

METHODS

A reference model containing four analogs and PAD were fabricated by a 3D printer (AccuFab-C1s, 3DShining). 10 digital scans were performed using an intraoral scanner (Aoralscan 3, 3DShining), sv 1.0.0.3115, with artificial landmarks located at different arch positions: group I, without any artificial landmarks; group II, with artificial landmarks at the anterior region; group III, with artificial landmarks at the posterior region. group IV: with artificial landmarks at both anterior and posterior regions. For group V: Conventional open-tray splinted impressions. The reference file and conventional stone casts were digitalized by using a dental laboratory scanner. The related files were imported into inspection software for trueness and precision assessment. Statistical analysis was performed with One-way ANOVA and Kruskal-Wallis test. The level of significance was set at α=0.05.

RESULTS

For the global accuracy assessment, significantly higher global trueness was seen in group II (p < 0.01), III (p < 0.001), IV (p < 0.001) and V (p < 0.001) than group I. Significantly higher global precision was seen in group III (p < 0.001), IV (p < 0.001) and V (p < 0.001) than group I. For the local accuracy assessment, the PAD primarily improved accuracy on the linear deviations.

CONCLUSIONS

Artificial landmarks of PAD at different arch positions significantly influenced the scanning accuracy. Applying the PAD in group IV could achieve comparable outcomes to conventional open-tray splinted impressions. Artificial landmarks on the posterior region may be more pivotal than those on the anterior region.

CLINICAL SIGNIFICANCE

Group IV could achieve comparable accuracy to conventional open-tray splinted impressions.

Patient-reported outcome measures (PROMs) of digital and conventional impression methods for fixed dentures

BACKGROUND

Digital impression technique or computer-aided impression (CAI) has been recently concluded as a clinically acceptable alternative to conventional impression method (CIM) in the fabrication of crowns, short fixed partial dentures (FPDs), and implant-supported crowns.

OBJECTIVE

The purpose of this study was to investigate the patients' opinion and subjective perception of two different ways of impression - digital and conventional.

METHODS

A total of 45 patients were treated with CAI and CIM for the fabrication of tooth or implant-supported crowns. They fulfilled a questionnaire including 11 questions regarding the treatment time, gag reflex, discomfort related to manipulation, and other aspects of treatment.

RESULTS

CAI was considered the preferential method for future treatment in 53% of patients, whereas 28.9% of the respondents preferred CIM. The preference for the impression method was influenced by the total time spent with the procedure, discomfort during manipulation with the tray or scanning head, size of the tray or scanning head, maximal opening discomfort, and (the tendency towards) gag reflex.

CONCLUSION

CAI was considered a more comfortable and preferential method. Discomfort or difficulties during CAI negatively affected the patients' attitude to CAI, whereas the difficulties associated with CIM did not have any influence on the preferred method.

Effect of prefabricated auxiliary devices and scanning patterns on the accuracy of complete-arch implant digital impressions

OBJECTIVES

This study aimed to evaluate the impact of prefabricated auxiliary devices (PAD) and scanning patterns on the accuracy of complete-arch implant digital impressions.

METHODS

An edentulous maxillary model was inserted with four parallel implant analogs and four PAD. The model was scanned with D2000 dental laboratory scanner as the reference scans. Test scans were obtained by 8 different scanning patterns (SP), which including SPA, SPB, SPC, SPD, SPE, SPF, SPG and SPH, with (test group) or without (control group) using the PAD by an intraoral scanner (Aoralscan 3, 3DShining). SPA was the scanning pattern recommended by the manufacturer. Each scanning time was recorded. The related files were imported into inspection software for assessment. Aligned Ranks Transformation ANOVA, Kruskal-Wallis and Mann-Whitney tests were used to evaluate the values. The level of significance was set at α = 0.05.

RESULTS

The scanning patterns significantly influenced the linear accuracy in the test group and the scanning time for both groups. Lower linear trueness in the test group was found in SPF (p<0.05) and SPG (p<0.05). Longer scanning time was found in SPB and SPG for both groups. The test group demonstrated linear accuracy enhancement in all the scanning patterns; angular trueness enhancement was seen in SPA (p<0.05), SPC (p<0.01) and SPH (p<0.01). Significant longer scanning time was found in SPB (p<0.05), SPF (p<0.05), SPG (p<0.05) and SPH (p<0.05) when using PAD.

CONCLUSION

The scanning patterns impact the accuracy differently depending on the PAD's existence. The scanning time can be significantly influenced by the scanning patterns and the PAD.

CLINICAL SIGNIFICANCE

In daily clinical practice, selecting a suitable scanning pattern is significant in achieving accurate digital impressions. The PAD demonstrated effective linear accuracy enhancement in all the scanning patterns tested.

Influence of scanbody design and intraoral scanner on the trueness of complete arch implant digital impressions: An in vitro study

This study aimed to compare the accuracy of full-arch digital implant impressions using seven different scanbodies and four intraoral scanners. A 3D-printed maxillary model with six implants and their respective multi-unit abutments was used for this study. Seven scanbodies (SB1, SB2, SB3, SB4, SB5, SB6, and SB7) and four intraoral scanners (Primescan®, Omnican®, Trios 3®, and Trios 4®) were assessed. Each combination group was scanned ten times and a dental lab scanner (D2000, 3Shape) was used as a reference. All scans were exported as STL files, imported into Convince software (3Shape) for alignment, and later into Blender software, where their 3D positions were analyzed using a Python script. The 3D deviation, angular deviation, and linear distance between implants #3 and #14 were also measured. Accuracy was measured in terms of "trueness" (scanbody 3D deviation between intraoral scan and desktop scan). Kruskal-Wallis followed by the Bonferroni correction was used to analyze the data (⍺ = .05). The study found statistically significant differences in digital impression accuracy among the scanners and scanbodies (p<0.001). When comparing different intraoral scanners, the Primescan system showed the smallest 3D deviation (median 110.59 μm) and differed statistically from the others, while Trios 4 (median 122.35 μm) and Trios 3 (median 130.62 μm) did not differ from each other (p = .284). No differences were found in the linear distance between implants #3 and #14 between Trios 4, Primescan, and Trios 3 systems. When comparing different scanbodies, the lowest median values for 3D deviation were obtained by SB2 (72.27μm) and SB7 (93.31μm), and they did not differ from each other (p = .116). The implant scanbody and intraoral scanner influenced the accuracy of digital impressions on completely edentulous arches.

Accuracy of 2 direct digital scanning techniques-intraoral scanning and stereophotogrammetry-for complete arch implant-supported fixed prostheses: A prospective study

STATEMENT OF PROBLEM

Conventional impression techniques for complete arch implant-supported prostheses are technique-sensitive. Stereophotogrammetry (SPG) and intraoral scanning (IOS) may offer an alternative to conventional impression making.

PURPOSE

The purpose of this prospective study was to compare the accuracy of IOS and SPG for complete arch implant scans and to evaluate the passive fit of frameworks fabricated with SPG.

MATERIAL AND METHODS

Laboratory scanning of gypsum casts, SPG, and IOS were performed for all participants. The data regarding the abutment platform were superimposed to calculate the 3D deviation of SPG and IOS compared with that of laboratory scanning as an evaluation of accuracy. The effect of implant position and number on accuracy was analyzed. The more accurate technique between SPG and IOS was used to fabricate the titanium frameworks, as was laboratory scanning. The passive fit of the frameworks was assessed by clinical examination, the Sheffield test, and panoramic radiography.

RESULTS

Seventeen participants (21 arches, 120 implants) were included. The accuracy of SPG ranged from 2.70 μm to 92.80 μm, with a median (Q1, Q3) of 17.00 (11.68, 22.50) μm, which was significantly more accurate than that of IOS, ranging from 21.30 μm to 815.60 μm, with a median (Q1, Q3) of 48.95 (34.78, 75.88) μm. No significant correlation was found between position or number of implants and 3D deviation in the SPG group. A weak positive correlation was found between implant number and 3D deviation in the IOS group. SPG and laboratory scanning were used to fabricate titanium frameworks. The passive fit between the frameworks and abutment platforms was confirmed.

CONCLUSIONS

SPG, which was not affected by position or number of implants, was more accurate than IOS and comparable with laboratory scanning. The frameworks fabricated based on SPG and laboratory scanning were comparable in their passive fit. The SPG technique may be an alternative to laboratory scanning for complete arch implant scans.

Intraoral Scan Accuracy and Time Efficiency in Implant-Supported Fixed Partial Dentures: A Systematic Review

The digital implant impression technique (DIT) and conventional implant impression technique (CIT) workflows in implant-supported fixed partial dentures (FPDs) have not been extensively compared in prior studies. Moreover, there is no agreement on the more accurate method that entails less time in the laboratory and during the clinical phases of fabrication and delivery of the prosthesis, respectively. This review aimed to assess the precision of the imaging procedure and overall fabrication time of the DIT and CIT for the implant-supported FPDs. An electronic search was performed using PubMed, Scopus, EMBASE, Cochrane Oral Health Group, and Dentistry and Oral Science Source databases through EBSCO for relevant studies from January 2014 to April 2023. Following the preliminary screening, the studies that met the inclusion criteria underwent full-text review in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The Cochrane Collaboration risk of bias appraisal tool and Newcastle-Ottawa scale were applied to assess the quality of randomized controlled trials (RCTs) and non-randomized prospective clinical studies, respectively. The initial search yielded 332 studies, and after excluding duplicates, 241 papers were available for screening. Titles and abstracts were reviewed, and 97 articles were chosen for full-text review by two authors independently. Furthermore, 89 articles were excluded in compliance with the PICOS question, and eight studies were chosen for qualitative analysis. Hence, the review comprised two RCTs and six prospective clinical studies. The time efficiency of the implant-supported FPDs was examined in four investigations, three of which used the Trios 3 scanner and one used the Intero scanner. The three-dimensional accuracy of DIT and CIT was compared in six clinical comparative studies. One of the RCTs was rated to have a high risk of bias and the other with a moderate quality of evidence. The six prospective studies were rated to have high-quality of evidence. The findings of this review indicate the prospective applicability of future intraoral scanning systems. The DIT was reported to be outstanding in terms of patient preferences and total fabrication time efficiency. Additional in vivo studies are needed to establish the therapeutic usefulness and time efficiency of integrating DIT in more comprehensive settings.

Integrating a complete denture digital workflow with polished surface registration: A single-procedure clinical protocol

Intraoral digital scanning of edentulous arches has provided the dental profession with the ability to obtain genuinely mucostatic impressions. The drawback, because of the omission of border molding procedures, has been underextended flanges which might affect the retention and stability of the definitive prosthesis. A technique for combining the concept of registering the polished surfaces with a functional impression material and the intraoral digital mucostatic scanning workflow is described.

Evaluation of Intraoral Full-Arch Scan versus Conventional Preliminary Impression

An accurate impression is vital during prosthodontic rehabilitation. Digital scanning has become an alternative to conventional impressions. This study compares conventional preliminary impression techniques with digital scanning, evaluating the efficiency, treatment comfort, and trueness. Impressions of 28 patients were taken using conventional and digital techniques. The efficiency of both impression techniques was evaluated by measuring the mean working time. A visual analog scale questionnaire (1-10) was used to appreciate the participants' perceptions of discomfort. Morphometric measurements, which were carried out to determine the differences between the casts, were made on the buccolingual cross sections of teeth 11 and 31 and the distolingual and mesiobuccal cusp tips of each first molar. The total treatment time was 75.5 min for conventional and 12 min for digital impressions. The patients scored a mean discomfort assessment of 6.66 for conventional and 9.03 for digital scanning. No significant differences existed between the examined areas (p < 0.05, Wilcoxon and Mann-Whitney tests) of the digital casts obtained by both techniques. The intraoral scan can be considered as an alternative to conventional preliminary impressions for performing study model analysis during orthodontic treatment planning. The digital impression is more comfortable and accepted by the patients than the conventional impression and has a shorter working time.

Reverse scan technique: A verification method for the implant position in intraoral scans

This article describes a fully digital method of verifying and increasing the accuracy of the position of implants in extensive prosthetic restorations. This cost-effective, timesaving, and versatile procedure uses a laboratory scanner, a scannable implant analog, and a printed interim implant-supported prosthesis to refine the virtual definitive cast.

Effect of translucency of CAD-CAM ceramic restorative materials and scanning aid conditions on the accuracy of intraoral scans

Background/purpose

Subsurface scattering from translucent material would affect the digital scans. This study aimed to evaluate the effect of translucency of ceramic restorative materials and scanning aid conditions on the accuracy of intraoral scans.

Materials and methods

Identical anatomic contour crowns with ten ceramic restorative materials were fabricated: five zirconia, three lithium disilicate glass-ceramic, and two leucite reinforced glass-ceramic. The models with ceramic crowns were digitized with an intraoral scanner (IOS) and analyzed for accuracy (n = 10) with and without a scanning aid. Scan time efficiency was recorded. Square-shaped specimens with 1.0-mm thickness were fabricated with the same materials, and translucency parameter (TP) values were measured. One-way ANOVA, Welch ANOVA, and a post-hoc pairwise comparison or independent t-test were used for trueness and time analysis, and the F-test was used to examine the precision (α = 0.05). Pearson correlation test was conducted.

Results

Significant differences were revealed for trueness with no scanning aid condition and for TP values (P < 0.05). In contrast, no statistically significant differences were observed for trueness with a scanning aid. A strong correlation (r = 0.854, P < 0.01) between TP value and trueness with no scanning aid was revealed. By applying a scanning aid, trueness was improved and scan time efficiency significantly increased (P < 0.05).

Conclusion

The translucency of ceramic restorative materials negatively affects the accuracy of IOS scan without a scanning aid; however, the scan accuracy and time efficiency of IOS scanning for ceramic restorations can be improved by applying scanning aid, and prostheses with high quality without unnecessary labor can be produced.

Digital restorative workflows for developmental dental defects in young patients: A case series

BACKGROUND

Digital technology is rapidly changing the provision of oral health care, although its adoption for the oral health care of young patients has lagged. The authors describe digitally supported treatment approaches for managing treatment of developmental dental defects in the early permanent dentition.

CASE DESCRIPTION

Four adolescent patients with amelogenesis imperfecta received transitional anterior restorations for esthetic and functional rehabilitation using a variety of digital workflows. Combinations of restoration type, materials, and fabrication methods were selected to meet the needs of each patient on the basis of their specific amelogenesis imperfecta phenotype and chief symptoms. These cases highlight the application of digital technology in pediatric and adolescent dentistry for managing the treatment of developmental dental defects.

PRACTICAL IMPLICATIONS

Digitally supported restorative approaches, as described in this report, offer broad applicability of materials and techniques directed at treating the complex restorative needs of young patients in the transitional and early permanent dentition.

Composite plastering technique (CPT) for anterior and posterior restorations

Composite plastering technique (CPT) is a novel restoration improvement technique for eliminating and re-contouring the marginal defects. Restoration-related interproximal contour deficiencies such as dark triangles beneath the contact point following direct class II restorations, the gaps at the interproximal cavity step following indirect cementations, and the gaps at the interproximal wall following class III restoration layering procedures can be corrected using the CPT. The technique may also be used as a layering step during the free-hand layering in diastema closure restorations. Contour deficiencies on interproximal surfaces which lead to the renewal of restoration and periodontal damages can be prevented by additional direct composite build-up using the CPT. The technique can be performed either immediately after the restoration directly or long after by using the composite repair protocol. It focuses on filling and re-contouring the surface of the deficiency by using a mylar strip actively under rubberdam isolation. Composite is loaded between the strip and the tooth surface and the strip is pulled slightly in palato-buccal or the opposite direction depending on the location of the defect, to fill it by plastering the composite. It may contribute the longevity of the restoration by improving the emergence profile and correcting the interproximal contour. Re-contouring of the interproximal surface defects by CPT is a useful approach to improve the esthetics as well as the function of anterior and posterior direct and indirect restorations which may also prolong the longevity.

Trueness of full-arch dental models obtained by digital and conventional impression techniques: an in vivo study

The aim of this study was to compare the trueness of complete- and partial-arch impressions obtained using conventional impression materials and intraoral scanners in vivo. Full-arch impressions were taken using polyether and polyvinylsiloxane. Gypsum casts were digitized using a laboratory scanner (IM, AF). Casts obtained from polyether impressions were also scanned using an industrial blue light scanner to construct 3D reference models. Intraoral scanning was performed using CEREC Omnicam (CO) and Trios 3 (TR). Surface matching software (Atos Professional) enabled to determine the mean deviations (mean distances) from the reference casts. Statistically significant discrepancies were calculated using the Wilcoxon signed-rank test. The mean distance for trueness ranged from 0.005 mm (TR) to 0.023 mm (IM) for the full arch, from 0.001 mm (CO) to 0.068 mm (IM) for the anterior segment, and from 0.019 mm (AF) to 0.042 mm (IM) for the posterior segment. Comparing the anterior vs. the posterior segment, significantly less deviations were observed for anterior with CO (p < 0.001) and TR (p < 0.001). Full-arch comparisons revealed significant differences between AF vs. IM (p = 0.014), IM vs. CO (p = 0.002), and IM vs. TR (p = 0.001). Full-arch trueness was comparable when using Affinis and the two intraoral scanners CEREC Omnicam and Trios 3. The digital impression devices yielded higher local deviations within the complete arch. Digital impressions of the complete arch are a suitable and reliable alternative to conventional impressions. However, they should be used with caution in the posterior region.Trial registration: Registration number at the German Clinical Trial Register (04.02.2022): DRKS00027988 ( https://trialsearch.who.int/ ).

Implementation of a Full Digital Workflow by 3D Printing Intraoral Splints Used in Dental Education: An Exploratory Observational Study with Respect to Students' Experiences

Fully digital workflows gained acceptance in dental practice and thereby are of interest for undergraduate education. An exploratory clinical observation was designed to track the implementation of such a workflow with novice digital users in order to describe its feasibility, time investment, and pitfalls.

METHODS

Students were invited to provide feedback for their experiences with a training module that consisted of the following: intraoral scanning, computer-aided design (CAD), manual finishing, and insertion of a 3D-printed bite splint for the lower jaw.

RESULTS

A total of 82 fourth-year students participated in the module. The average time required to perform an intraoral scan was 17 m 5 s, and all students were able to design a splint with an average time of 2 h 38 m. Students who indicated prior experience with CAD seem to outperform inexperienced students in both CAD task completion and intraoral scanning. The initial fit was reported as clinically acceptable by 68.5% of the participants, while 79% rated the workflow as very good to satisfactory and indicated that the training was helpful for dental practice.

CONCLUSIONS

The implementation of a digital workflow in undergraduate dental education is feasible and has acceptable clinical results. However, CAD is time-intensive, and the experience can be challenging.

Effect of different surface treatments on resin-matrix CAD/CAM ceramics bonding to dentin: in vitro study

BACKGROUND

Evaluating the effect of different surface treatment methods on the micro-tensile bond strength (µTBS) of two different resin-matrix computer-aided design/computer-aided manufacturing (CAD/CAM) ceramics (RMCs).

METHODS

A standardized inlay preparations were performed on 100 intact maxillary premolars. According to the type of the restorative material, the teeth were randomly divided into two equally sized groups (n = 50): (polymer-infiltrated ceramic (Vita Enamic) and resin-based composites (Lava Ultimate)). The inlays were fabricated using CAD/CAM technology. In each group, the specimens were randomly assigned to five subgroups (n = 10) according to the surface treatment method: group 1 used was the control group (no surface treatment); group 2, was treated with air abrasion with 50 μm Al2O3 (A) and universal adhesive (UA); group 3, was treated with air abrasion with 50 μm Al2O3 (A) and silane coupling agent (S); group 4, was treated with hydrofluoric acid (HF) and universal adhesive (UA) and group 5, was treated with Hydrofluoric acid (HF) + silane coupling agent (S). The inlays were then cemented to their respective preparations using dual-cure self-adhesive resin cement (RelyX U200, 3 M ESPE) according to the manufacturer's instructions. The µTBS test was conducted in all groups, and stereomicroscope and scanning electron microscope were used to inspect the failure mode. The data were statistically analyzed using a two-way analysis of variance (ANOVA) and Tukey's post-hoc multiple comparison tests at a significance level of p < 0.05.

RESULTS

Surface treatments significantly increased the µTBS of the materials compared to the control group (p < 0.05). For CAD/CAM RBCs, the µTBS value highest in group 2 whereas, for PICN, the µTBS value was highest in group 3. Cohesive failure of CAD/CAM restorative material was the most predominant mode of failure in all treated groups, whereas adhesive failure at restoration-cement interface was the most predominant failure mode in the control group.

CONCLUSION

Surface treatments increase the µTBS of resin-matrix CAD/CAM ceramics to tooth structure. Air abrasion followed by universal adhesive and hydrofluoric acid followed by silane application appears to be the best strategies for optimizing the bond strength of CAD/CAM RBCs and PICN respectively.

Effect of defect size and tooth anatomy in the measurements of a 3D patient monitoring tool

Purpose

To assess the influence of defect size and tooth anatomy on the measurements performed by a 3D patient monitoring tool.

Methods

A fully dentate model was scanned to obtain a master digital file. Virtual duplicates received defects created in molars (16, 18, 28) and incisors (11, 12, 22), according to different depths (60, 80, 120 microns) and sizes (small, medium, large) totaling 180 conditions. The surface changes measured by the 3D Patient Monitoring Tool (3Shape TRIOS Patient Monitoring [TPM]) were compared with the reference by 2 calibrated operators. False Positives (FP), and False Negatives (FN) defect were registered. Pearson chi-square test, Multivariate binary logistic regression and Spearman rank correlation were used to evaluate the data (α = 0.05).

Results

A significant association was found between the area and the presence of FP and FN (P < .01). Larger defects had higher chances to present FP or an FN respectively. There was a significant association between the tooth and the presence of a FP value (FP, P = .02; FN, P = .005) specially in molars. No significant association was found between the defect depth and the presence of a FP value. Spearman rank correlation showed a strong association between the presence of an FP and an FN (r = 0.858, P < .01).

Conclusions

The defect size and tooth anatomy significantly affected the virtual follow-up, whereas defect depth did not. Small defects were correctly detected in all cases. An incorrect measurement on one side of the tooth simultaneously resulted in incorrect measurement on the opposite side.

Clinical relevance

The clinician should be aware that different factors related to the characteristics of the defects could affect the quality of the full-arch digital follow-up. Therefore, caution is needed when interpreting the models comparison in cases that a larger area of a tooth has been modified.

Marginal and Internal Misfit of Occlusal Veneers Made in Resin-matrix Ceramics

Objective

Considering that misfit is a significant predictor of the clinical success of indirect restorations, the objective of this study was to evaluate the marginal and internal misfit of two computer-aided design and manufacturing (CAD/CAM) RMC ceramic materials used as occlusal veneers (OVs) of different thicknesses.

Methods and Materials

A CAD model of a mandibular first molar was obtained and OV preparations 0.5-, 1.0-, and 1.5-mm thick were modeled and milled in two different materials (n=10/group): resin nanoceramic (RNC) and polymer-infiltrated ceramic network (PICN). Using the same CAD model, tooth preparations were milled in fiber-reinforced epoxy resin (n=20/thickness). The marginal and internal misfit of the restorations was assessed by X-ray microtomography. The measurements of the marginal gap (MG) and absolute marginal discrepancy were performed in two locations on each slice, whereas internal gap (IG) measurements were performed at ten locations on each slice. The data obtained were analyzed using two-way analysis of variance and Tukey post-hoc tests (α=0.05).

Results

No significant effect was attributable to the material type or material–thickness interaction for the MG, absolute marginal discrepancy (AMD), or IG (p&gt;0.05). However, the thickness significantly affected the IG of the restorations (p&lt;0.05). CAD/CAM RNC and PICN systems presented similar MG and AMD for OVs 0.5-, 1.0-, and 1.5-mm thick. However, the IG varied between thicknesses.

Procedure Time and Students’ Perception Comparing Full Arch Digital Scans with Conventional Impressions: A Cross-Over Randomized Experimental Trial

Methods

Ninety-six dental students each prepared tooth #36 for an all-ceramic crown on typodont models and were then randomly assigned into either group A: performed digital scan first, or Group B: performed conventional impression first. Procedure time was recorded for both. Immediately following each procedure, students indicated their perceived procedure difficulty. After exposure to both techniques, they selected their preferred one.

Results

There was a statistically significant difference between the mean procedure time of both techniques (P < 0.0001), where students spent 663.76 ± 442.50 seconds to complete the conventional impression and 293.32 ± 181.49 seconds to complete the digital scan. Females were significantly faster in completing the conventional impression compared to males. On the contrary, male students were faster in digital scanning than female students. There were no carryover effects in the duration and the initially performed procedure. 76% (73 of 96) of participants preferred digital scanning with no statistical significance shown between the preferred and initially performed procedure. Participants perceived conventional impressions to be more difficult than digital scans. There was a weak positive correlation between the VAS score and the procedure time for the digital technique (R = 0.25) and a moderate positive correlation for the conventional technique (R = 0.45).

Conclusions

The digital technique was preferred and perceived as easier than the conventional among undergraduate dental students with no impression-making experience, suggesting their readiness for new technology uptake. However, no significant correlation was found between the initially performed procedure and preference.

Mechanical response of different frameworks for maxillary all-on-four implant-supported fixed dental prosthesis: 3D finite element analysis

This study's purpose is to assess the stress distribution in the peri-implant bone, implants, and prosthetic framework using two different posterior implant angles. All-on-four maxillary prostheses fabricated from feldspathic-ceramic-veneered zirconia-reinforced lithium silicate (ZLS) and feldspathic-ceramic-veneered cobalt-chromium (CoCr) were designed with 17 or 30-degree-angled posterior implants. Posterior cantilever and frontal vertical loads were applied to all models. The distribution of maximum and minimum principal stresses (σmax and σmin) and von Mises stress (σVM) was evaluated. Under posterior cantilever load, with an increase in posterior implant angle, σmax decreased by 4 and 7 MPa in the cortical bone when ZLS and CoCr were used as a prosthetic framework, respectively. Regardless of the framework material, 17-degree-angled posterior implants showed the highest σVM (541.36 MPa under posterior cantilever load; 110.79 MPa under frontal vertical load) values. Regardless of the posterior implant angle, ZLS framework showed the highest σVM (91.59 MPa under posterior cantilever load; 218.99 MPa under frontal vertical load) values. Increasing implant angle from 17 to 30° caused a decrease in σmax values in the cortical bone. Designs with 30-degree posterior implant angles and ZLS framework material may be preferred in All-on-four implant-supported fixed complete dentures.

Comparison of accuracy between digital and conventional implant impressions: two and three dimensional evaluations

PURPOSE

The present study compared the accuracy between digital and conventional implant impressions.

MATERIALS AND METHODS

The experimental models were divided into six groups depending on the implant location and the scanning span. Digital impressions were captured using the intraoral optical scanner TRIOS (3Shape, Copenhagen, Denmark). Conventional impressions were taken with the monophase impression material based on addition-cured silicones, Honigum-Mono (DMG, Hamburg, Germany). A high-precision laboratory scanner D900 (3Shape, Copenhagen, Denmark) was used to obtain digital data of resin models and stone casts. Surface tessellation language (STL) datasets from scanner were imported into the analysis software Geomagic Qualify 14 (3D Systems, Rock Hill, SC, USA), and scan body deviations were determined through two-dimensional and three-dimensional analyses. Each scan body was measured five times. The Sidak t test was used to analyze the experimental data.

RESULTS

Implant position and scanning distance affected the impression accuracy. For a unilateral arch implant and the mandible models with two implants, no significant difference was observed in the accuracy between the digital and conventional implant impressions on scan bodies; however, the corresponding differences for trans-arch implants and mandible with six implants were extremely significant (P<.001).

CONCLUSION

For short-span scanning, the accuracy of digital and conventional implant impressions did not differ significantly. For long-span scanning, the precision of digital impressions was significantly inferior to that of the traditional impressions.

Clinical Outcome of Fully Digital Workflow for Single-Implant-Supported Crowns: A Retrospective Clinical Study

A digital workflow by means of intraoral scanners and computer tomography has been used in dental implantology, allowing clinicians to be potentially more accurate and precise. Computer-Aided Design and Computer-Aided Manufacturing (CAD-CAM) and 3D models facilitate the process from treatment planning to the surgical procedure, up to the implant placement and final prosthesis. The aim of the present retrospective study was to evaluate a fully digital workflow for single-tooth implant rehabilitation. A total of 19 patients (22 implants) were included in the present study, with a mean follow-up time of 2 years. A fully digital workflow was performed on each patient through the planning, design and printing of a surgical guide, following a digital impression made with an intraoral scanner, computer-tomography-guided implant placement and, finally, with the delivery of a CAD-CAM crown. The two-year follow-up results were satisfactory in terms of the aesthetic yield and precision of the prosthesis. In single-implant-supported restorations, due to digital protocols and digital planning, a reduced number of clinical sessions was registered and the treatment plan results were more predictable. Future studies are needed to understand the application of fully digital protocols in cases of partially or totally edentulous patients.

Comparative assessment of complete-coverage, fixed tooth-supported prostheses fabricated from digital scans or conventional impressions: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Intraoral scanners have significantly improved over the last decade. Nevertheless, data comparing intraoral digital scans with conventional impressions are sparse.

PURPOSE

The purpose of this systematic review and meta-analysis was to determine the impact of impression technique (digital scans versus conventional impressions) on the clinical time, patient comfort, and marginal fit of tooth-supported prostheses.

MATERIAL AND METHODS

The authors conducted a literature search based on the Population, Intervention, Comparison, and Outcome (PICO) framework in 3 databases to identify clinical trials with no language or date restrictions. The mean clinical time, patient comfort, and marginal fit values of each study were independently extracted by 2 review authors and categorized according to the scanning or impression method. The authors assessed the study-level risk of bias.

RESULTS

A total of 16 clinical studies met the inclusion criteria. The mean clinical time was statistically similar for digital scan procedures (784 ±252 seconds) and for conventional impression methods (1125 ±159 seconds) (P>.05). The digital scan techniques were more comfortable for patients than conventional impressions; the mean visual analog scale score was 67.8 ±21.7 for digital scans and 39.6 ±9.3 for conventional impressions (P<.05). The mean marginal fit was 80.9 ±31.9 μm and 92.1 ±35.4 μm for digital scan and conventional impressions, respectively, with no statistically significant difference (P>.05).

CONCLUSIONS

Digital scan techniques are comparable with conventional impressions in terms of clinical time and marginal fit but are more comfortable for patients than conventional impression techniques.

Digital versus Traditional Workflow for Immediate Loading in Single-Implant Restoration: A Randomized Clinical Trial

The purpose of this randomized controlled trial was to compare the immediate-loading protocol, in single restorations in the esthetic zone, by comparing the digital workflow in a test group (TG) vs. the analogical workflow in a control group (CG). A total of 50 patients were enrolled, requiring single hopeless tooth extraction. Twenty-five patients (TG) were randomly assigned to the immediate-loading protocol using the digital workflow, and twenty-five patients (CG) were assigned to the conventional workflow. Clinical and radiographic parameters were evaluated at the time of implant insertion (baseline) and after 3, 6 and 12 months, respectively. A clinician blind to conditions measured the Pink Esthetic Score (PES), as well as patient satisfaction. At 12-month follow-up, a cumulative survival rate of 100% was reported for all implants. No failures or biological complications were observed. No statistically significant differences were detected in the mean values of marginal bone loss and PES between the TG (0.12 ± 0.66 mm for MBL, 7.75 ± 0.89 for PES) and the CG (0.15 ± 0.54 mm for MBL, 7.50 ± 0.89 for PES). In 11 cases of TG, and 10 cases of CG, a one-year follow-up period showed an increased marginal bone level. No statistically significant differences were found in the mean total PES between test (7.75 ± 0.89) and control (7.5 ± 0.81) conditions. Furthermore, a customer satisfaction survey showed that patients preferred the digital workflow over the conventional workflow procedure (97.6 ± 4.3 vs. 69.2 ± 13.8). Digital workflow was more time-efficient than conventional workflow (97.2 ± 7.3 vs. 81.2 ± 11.3). Within the limitations of this study, no statistically significant differences were found between digital and traditional workflow.

Intraoral scanning reduces procedure time and improves patient comfort in fixed prosthodontics and implant dentistry: a systematic review

OBJECTIVES

The primary aim of this systematic review was to evaluate whether intraoral scanning (IOS) is able to reduce working time and improve patient-reported outcome measures (PROMs) compared to conventional impression (CI) techniques, taking into account the size of the scanned area. The secondary aim was to verify the effectiveness of IOS procedures based on available prosthodontic outcomes.

MATERIALS AND METHODS

Electronic and manual literature searches were performed to collect evidence concerning the outcomes of IOS and CI performed during the treatment of partially and complete edentulous patients for tooth- or implant-supported restorations. Qualitative analysis was conducted to evaluate the time efficiency and PROMs produced by the two different techniques. Clinical prosthodontic outcomes were analyzed among the included studies when available.

RESULTS

Seventeen studies (9 randomized controlled trials and 8 prospective clinical studies) were selected for qualitative synthesis. The 17 included studies provided data from 430 IOS and 370 CI performed in 437 patients. A total of 7 different IOS systems and their various updated versions were used for digital impressions. The results demonstrated that IOS was overall faster than CI independent of whether quadrant or complete-arch scanning was utilized, regardless of the nature of the restoration (tooth or implant supported). IOS was generally preferred over CI regardless of the size of the scanned area and nature of the restoration (tooth- or implant-supported). Similar prosthodontic outcomes were reported for workflows implementing CI and IOS.

CONCLUSIONS

Within the limitations of this systematic review, IOS is faster than CI, independent of whether a quadrant or complete arch scan is conducted. IOS can improve the patient experience measured by overall preference and comfort and is able to provide reliable prosthodontic outcomes.

CLINICAL RELEVANCE

Reduced procedure working time associated with the use of IOS can improve clinical efficiency and the patient experience during impression procedures. Patient-reported outcome measures (PROMs) are an essential component of evidence-based dental practice as they allow the evaluation of therapeutic modalities from the perspective of the patient. IOS is generally preferred by patients over conventional impressions.

Patient-related outcomes of conventional impression making versus intraoral scanning for prosthetic rehabilitation: A systematic review and meta-analysis

STATEMENT OF PROBLEM

Intraoral scanning has been reported to be preferred by patients over conventional impression making. Nevertheless, information regarding patient-related outcomes for conventional impression making and digital scanning is sparse.

PURPOSE

The purpose of this systematic review and meta-analysis was to analyze patient-related outcomes of intraoral scanning and conventional impression methods. The primary outcomes evaluated were patient preference and satisfaction, and the secondary outcomes discomfort, nausea, unpleasant taste, breathing difficulty, pain, and anxiety.

MATERIAL AND METHODS

Electronic and manual searches were performed for clinical trials that evaluated patient-related outcomes for intraoral scanning and conventional impression making for prosthetic rehabilitation. The Cochrane Collaboration risk of bias tool and Newcastle-Ottawa scale were used to assess the quality of the studies. Random-effects models using mean difference were used for meta-analyses. Heterogeneity was assessed using the Cochran Q test and I² statistics (α=.05).

RESULTS

The search strategy identified 1626 articles, and 11 studies were included in the meta-analyses. Patients preferred intraoral scanning to conventional impression making. The mean difference for patient preference was 15.02 (95% confidence interval of 8.33 - 21.73; P<.001). Discomfort, absence of nausea, absence of unpleasant taste, and absence of breathing difficulty were also significantly different (P<.05).

CONCLUSIONS

Intraoral scanning is a suitable alternative to conventional impression procedures, promoting less discomfort for patients sensitive to taste, nausea, and breathing difficulty than when conventional impression making techniques are used.

Techniques to improve the accuracy of complete-arch implant intraoral digital scans: A systematic review

STATEMENT OF PROBLEM

The best method of optimizing the accuracy of complete-arch intraoral digital scans is still unclear. For instance, the location of the scan bodies can be significantly distorted with respect to their actual positions, which would lead to a nonpassive fit of the definitive prosthesis.

PURPOSE

The purpose of this systematic review was to analyze available techniques for improving the accuracy of digital scans in implant-supported complete-arch fixed prostheses.

MATERIAL AND METHODS

Three databases (Medline, Embase, and Google Scholar) were searched, and the results obtained were supplemented by a hand search. Specific descriptors identified techniques whose objective were to increase the accuracy of digital scans in implant-supported complete-arch fixed prostheses. Titles and abstracts were screened by 2 independent reviewers, and unclear results were discussed with a third independent reviewer. A qualitative analysis based on procedural parameters was used. The interexaminer agreements of both were assessed by the Cohen kappa statistic, and the Risk of Bias Tool was used to assess the risk of bias across the studies.

RESULTS

A total of 17 techniques matching the inclusion criteria were evaluated. Higher accuracy but also differences regarding the need for supplementary devices, number of intraoral scans, and time consumption of clinical and software program steps were observed compared with the conventional digital scanning protocol. The use of a splinting device was common to most of the studies. The outcome variables for the evaluation of the effectiveness of these protocols were heterogeneous.

CONCLUSIONS

The use of additional techniques during intraoral scanning can improve accuracy in implant-supported complete-arch fixed prostheses. However, higher complexity for those procedures should be expected.

Accuracy Evaluation of Additively and Subtractively Fabricated Palatal Plate Orthodontic Appliances for Newborns and Infants-An In Vitro Study

Different approaches for digital workflows have already been presented for their use in palatal plates for newborns and infants. However, there is no evidence on the accuracy of CAD/CAM manufactured orthodontic appliances for this kind of application. This study evaluates trueness and precision provided by different CAM technologies and materials for these appliances. Samples of a standard palatal stimulation plate were manufactured using stereolithography (SLA), direct light processing (DLP) and subtractive manufacturing (SM). The effect of material (for SM) and layer thickness (for DLP) were also investigated. Specimens were digitized with a laboratory scanner (D2000, 3Shape) and analyzed with a 3D inspection software (Geomagic Control X, 3D systems). For quantitative analysis, differences between 3D datasets were measured using root mean square (RMS) error values for trueness and precision. For qualitative analysis, color maps were generated to detect locations of deviations within each sample. SM showed higher trueness and precision than AM technologies. Reducing layer thickness in DLP did not significantly increase accuracy, but prolonged manufacturing time. All materials and technologies met the clinically acceptable range and are appropriate for their use. DLP with 100 µm layer thickness showed the highest efficiency, obtaining high trueness and precision within the lowest manufacturing time.

A fully digital approach for implant fixed complete dentures: A case report

INTRODUCTIONS

Intraoral scanner has been widely used for implant impression in partially edentulous cases; however, its accuracy in the impression of full-arch implant is still questionable.

CLINICAL REPORT

This clinical report presents a technique to check the accuracy of intraoral scanning for complete-arch implant restorations using an implant index cast (The Glossary of Prosthodontic Terms 9th Edition) and a three-dimensional printed cast. A clinical case of immediate loading on a maxillary edentulous patient illustrates the application of an implant index cast in implant fixed complete dentures (IFCDs).

DISCUSSION

The implant index cast was fabricated based on the immediate interim prosthesis and provides effective control of the fit of scanned files and printed models. Therefore, this approach allows a more predictable and accurate fit of the final prosthesis.

CLINICAL SIGNIFICANCE

In this article, we present a technique to check the accuracy of the final prosthesis without the need for a conventional impression and final cast in a digital workflow. This proposed approach is demonstrated through a case report of a maxillary edentulous patient restored with immediate loaded IFCDs.

Clinical performance of intraoral digital impression for fixed prosthodontics: a Meta-analysis

OBJECTIVES

To analyze the clinical performance of the intraoral digital impression (IDI) in the fixed prosthodontics.

METHODS

Databases of Medline (Ovid), EMBASE, Cochrane Central Register of Controlled Trials, and CNKI were searched for randomized controlled trial (RCT) on the use of IDI in fixed prosthodontics until May 2020. Two reviewers independently screened literature, extracted data, and assessed the risk of bias of included studies. A Meta-analysis was conducted when available.

RESULTS

Eleven RCTs involving 618 patients were included in this study. A total of 2 and 3 studies had low and high risks of bias, respectively, and other included studies had a medium risk of bias. Results illustrated that the IDI group could shorten the impression-taken time [SMD=-5.63, 95%CI (-11.25, -0.01), P=0.05] and improve the accuracy of the marginal fit [SMD=-0.53, 95%CI (-0.84, -0.22), P=0.000 7] compared with the conventional impression group. However, no significant difference was observed in the internal fit.

CONCLUSIONS

Evidence indicated a good clinical performance of IDI for fixed prosthodontics. Notably, high-quality studies are expected to further support the conclusion.

Effects of inter-implant distance on the accuracy of intraoral scanner: An in vitro study

PURPOSE

Several studies focused on the accuracy of intra-oral scanners in implant dentistry, but the data of inter-implant distances were not widely mentioned. Therefore, this study aimed to evaluate the effect of distance between two implants on the surface distortion of scanned models generated by intra-oral scanners.

MATERIALS AND METHODS

Three models with the distances between two fixed scan bodies of 7, 14, and 21 mm were fabricated and scanned with a highly precise D900L dental laboratory scanner as reference models. Fifteen scans were performed with TRIOS3 and CEREC Omnicam intra-oral scanners. Trueness, precision, and angle deviation of the test models were analyzed (α=.05).

RESULTS

There was a significant difference among inter-implant distances in both intraoral scanners (P <.001). The error of trueness and precision increased with the increasing inter-implant length, while the angle deviation did not show the same trend. A significant difference in the angle deviation was found among the inter-implant distance. The greatest angle deviation was reported in the 14-mm group of both scanners (P <.05). In contrast, the lowest angle deviation in the 21-mm group of the TR scanner and the 7-mm of the CR scanner was reported (P <.001).

CONCLUSION

The inter-implant distance affected the accuracy of intra-oral scanner. The error of trueness and precision increased along with the increasing distance between two implants. However, the distortions were not clinically significant. Regarding angle deviation, the clinically significant angle deviation may be possible when using intra-oral scanners in the partially edentulous arch.

Patient preference and clinical working time between digital scanning and conventional impression making for implant-supported prostheses: A systematic review and meta-analysis

STATEMENT OF PROBLEM

The technology behind optical scanners has greatly improved recently, making their dental application advantageous. While their accuracy is now comparable with that of conventional impression materials, whether these techniques have other advantages is unclear.

PURPOSE

The purpose of this systematic review and meta-analysis was to determine whether digital scanning for implant-supported restorations is more time-efficient and convenient for the patient.

MATERIAL AND METHODS

The study was conducted on September 23, 2020 using 4 different databases (Medline, Cochrane, Web of Science, Scopus) searching for clinical studies that compared the time needed and/or patient perceptions between those who had undergone the digital scanning procedure and those who had undergone conventional impression making.

RESULTS

Twelve studies met the inclusion criteria for qualitative and quantitative analysis. Outcome variables were measured as standard mean differences (SMDs) by following a fixed-effects model or random-effects model (in the case of high heterogeneity). Digital scanning was more time-efficient and was preferred by patients for all 4 analyzed outcomes (comfort, anxiety, nausea, time perception).

CONCLUSIONS

Digital scanning was found to be more time-efficient and convenient than conventional impression making for implant-supported restorations. Additional randomized controlled trials are needed to confirm the findings of this review.

Restorative CAD/CAM materials in dentistry: analysis of their fluorescence properties and the applicability of the fluorescence-aided identification technique (FIT)

OBJECTIVES

This study investigated the fluorescence properties of the most commonly used fluorescent CAD/CAM materials for monolithic dental restorations and their suitability to perform the fluorescence-aided identification technique (FIT).

MATERIALS AND METHODS

A total of 175 different color shades (n = 1) from 13 CAD/CAM material brands were analyzed with a monochromator-based microplate reader. Additionally, dentin, enamel, and combined dentin-enamel specimens (respectively, n = 11) were analyzed for comparison purposes. The maximum fluorescence intensity, the corresponding excitation and emission wavelength, and the total fluorescence for the wavelength spectrum λ_ex = 395 nm - 415 nm used for FIT were determined.

RESULTS

All assessed CAD/CAM ceramics showed virtually no total fluorescence for the wavelength spectrum λ_ex = 395 nm - 415 nm used for FIT. CERASMART^TM, KZR-CAD HD 2, and LuxaCam Composite displayed total fluorescence values similar to that of the tooth hard substances. All other resin-based CAD/CAM materials showed a significantly higher total fluorescence than the tooth hard substances.

CONCLUSIONS

Apart from the mentioned exceptions, all CAD/CAM materials assessed could be suitable for the FIT, either because they are more fluorescent than hard tooth substances or because they do not fluoresce at all at the respective wavelength of λ_ex = 395 nm - 415 nm.

CLINICAL RELEVANCE

This study provides insight into the not yet well-known fluorescent properties of dental CAD/CAM materials. This knowledge is not only necessary to reproduce the fluorescence properties of natural teeth but also for the applicability of diagnostic fluorescence inducing techniques.

Patient-reported outcome measures and clinical assessment of implant-supported overdentures and fixed prostheses in mandibular edentulous patients: A systematic review and meta-analysis

STATEMENT OF PROBLEM

A consensus based on patients' perceptions as to whether to use overdentures or fixed prostheses to rehabilitate mandibular edentulous arches is limited.

PURPOSE

The purpose of this systematic review and meta-analysis was to compare the patient-reported outcome measures (PROMs) and clinical outcomes associated with implant-supported overdentures and fixed prostheses in edentulous mandibles.

MATERIAL AND METHODS

Nine electronic databases were searched for randomized clinical trials (RCTs) and nonrandomized clinical trials (N-RCTs). The risk of bias was assessed by the revised Cochrane risk of bias tool for RCTs (RoB 2) and N-RCT (ROBINS-I). Data sets for oral health-related quality of life (OHRQoL), satisfaction, survival rate, implant probing depth, and marginal bone loss were plotted, and the appropriate analyses were applied by using the Rev Man 5.3 software program. Certainty of evidence was also evaluated by means of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.

RESULTS

Ten eligible trials were included and evaluated quantitatively. For 3 domains of OHRQoL, fixed prostheses showed significantly higher quality of life when compared with overdentures regarding functional limitation (P<.001), physical disability (P=.001), and physical pain (P=.003). Fixed prostheses also improved satisfaction, when compared with overdentures for comfort (P=.02), ease of chewing (P<.001), retention (P<.001), and stability (P<.001). The same pattern was observed for overall OHRQoL (P=.01) and satisfaction (P=.01) in which fixed prostheses improved patient satisfaction. Only ease of cleaning presented greater satisfaction for the overdenture group. Clinical parameters did not differ statistically (P>.05) between both types of prosthesis.

CONCLUSIONS

Fixed rehabilitations for mandibular edentulous patients seem to be a well-accepted treatment from the patients' oral health perspective. However, mandibular overdentures are no less efficient than fixed prostheses in terms of clinical outcomes.

Operators matter - An assessment of the expectations, perceptions, and performance of dentists, postgraduate students, and dental prosthetist students using intraoral scanning

OBJECTIVE

to assess the expectations, perceptions and performance of different operators with varying backgrounds and training in the use of full-arch intraoral scanning (IOS).

METHODS AND MATERIALS

Dentists (DENT), postgraduate dental students (DPG), and student prosthetists (PROS) were invited to join an IOS training workshop. Participants completed a satisfactory scan of a mannikin-mounted typodont with the total scanning time (TST) recorded. They also completed anonymised pre and post-training questionnaires covering their background, and IOS expectations and experience. Statistical analysis was performed using the Mann-Whitney U, Kruskal Wallis, and chi-square tests. Open-ended questions were analysed manually and using Leximancer.

RESULTS

Twenty-seven participants were recruited: 10 DENT; 10 PROS; and 7 DPG. Positive expectations of IOS was reported by 93 % of participants. Combined TST was 285 ± 83 s, with the PROS TST significantly longer (p < 0.05, 337 ± 79 s). Further training need was reported by 60 % of PROS and 50 % of DENT versus 14 % of DPG. Positive IOS experience was reported by 96 % of participants, 74 % perceived it to be accurate, and 63 % found it easy to use. Eighty-five percent of all participants stated that cost would influence their decision of adopting IOS in their practice.

CONCLUSION

Expectations and perceptions of IOS were overwhelmingly positive, irrespective of operator background and experience. Scanning performance and training needs depended on the operator's background. Cost of IOS remains a barrier to acquiring the technology.

CLINICAL SIGNIFICANCE

IOS training must be customised to accommodate the needs of different operators. The cost of IOS needs revision to improve its accessibility.

Volumetric changes at implant sites: A systematic appraisal of traditional methods and optical scanning-based digital technologies

AIM

To evaluate techniques for assessing soft tissue alterations at implant sites and compare the traditionally utilized methods to the newer three-dimensional technologies emerging in the literature.

MATERIALS AND METHODS

A comprehensive search was performed to identify interventional studies reporting on volumetric changes at implant sites following different treatments.

RESULTS

Seventy-five articles were included the following: 30 used transgingival piercing alone, one utilized calliper, six with ultrasonography, six on cone-beam computed tomography, and 32 utilized optical scanning and digital technologies. Optical scanning-based digital technologies were the only approach that provided 'volumetric changes,' reported as volumetric variation in mm³ , or the mean distance between the surfaces/mean thickness of the reconstructed volume. High variability in the digital analysis and definition of the region of interest was observed. All the other methods reported volume variation as linear dimensional changes at different apico-coronal levels. No studies compared volumetric changes with different approaches.

CONCLUSIONS

Despite the emergence of optical scanning-based digital technologies for evaluating volumetric changes, a high degree of variation exists in the executed workflow, which renders the comparison of study results not feasible. Establishment of universal guidelines could allow for volumetric comparisons among different studies and treatments.

Does a fully digital workflow improve the accuracy of computer-assisted implant surgery in partially edentulous patients? A systematic review of clinical trials

BACKGROUND

Accurate implant placement is essential in reducing post-treatment complications and in ensuring a successful treatment outcome.

PURPOSE

To compare the accuracy of fully-guided static computer-assisted implant surgery (s-CAIS) using partially- and fully-digital workflows.

MATERIALS AND METHODS

Electronic and manual literature searches were performed to collect evidence concerning the accuracy of fully-guided s-CAIS procedures utilizing tooth-supported guides. Quantitative analysis was conducted to evaluate the accuracy of partially- and fully-digital workflows, and survival rates and complications were qualitatively analyzed.

RESULTS

Thirteen studies, including 6 randomized controlled trials and 7 prospective clinical studies, were selected for quantitative and qualitative synthesis. A total of 669 implants in 325 patients using s-CAIS were available for review. Meta-analysis of the accuracy revealed a total mean angular deviation of 2.68° (95% CI: 2.32°-3.03°); mean global coronal deviation of 1.03 mm (95% CI: 0.88-1.18 mm); mean global apical deviation of 1.33 mm (95% CI: 1.17-1.50 mm); and mean depth deviation of 0.59 mm (95% CI: 0.46-0.70 mm). Minimal differences were found between the two different workflows. Few complications were reported, and survival rates were between 97.8% to 100% (range of follow-up: 12 to 24 months) in the available studies.

CONCLUSION

Similar accuracy is obtained when implants are placed in partially edentulous patients using fully-guided s-CAIS, independently of the workflow utilized.

Trueness of 12 intraoral scanners in the full-arch implant impression: a comparative in vitro study

BACKGROUND

The literature has not yet validated the use of intraoral scanners (IOSs) for full-arch (FA) implant impression. Hence, the aim of this in vitro study was to assess and compare the trueness of 12 different IOSs in FA implant impression.

METHODS

A stone-cast model of a totally edentulous maxilla with 6 implant analogues and scanbodies (SBs) was scanned with a desktop scanner (Freedom UHD®) to capture a reference model (RM), and with 12 IOSs (ITERO ELEMENTS 5D®; PRIMESCAN® and OMNICAM®; CS 3700® and CS 3600®; TRIOS3®; i-500®; EMERALD S® and EMERALD®; VIRTUO VIVO® and DWIO®; RUNEYES QUICKSCAN®). Ten scans were taken using each IOS, and each was compared to the RM, to evaluate trueness. A mesh/mesh method and a nurbs/nurbs method were used to evaluate the overall trueness of the scans; linear and cross distances between the SBs were used to evaluate the local trueness of the scans. The analysis was performed using reverse engineering software (Studio®, Geomagics; Magics®, Materialise). A statistical evaluation was performed.

RESULTS

With the mesh/mesh method, the best results were obtained by CS 3700® (mean error 30.4 μm) followed by ITERO ELEMENTS 5D® (31.4 μm), i-500® (32.2 μm), TRIOS 3® (36.4 μm), CS 3600® (36.5 μm), PRIMESCAN® (38.4 μm), VIRTUO VIVO® (43.8 μm), RUNEYES® (44.4 μm), EMERALD S® (52.9 μm), EMERALD® (76.1 μm), OMNICAM® (79.6 μm) and DWIO® (98.4 μm). With the nurbs/nurbs method, the best results were obtained by ITERO ELEMENTS 5D® (mean error 16.1 μm), followed by PRIMESCAN® (19.3 μm), TRIOS 3® (20.2 μm), i-500® (20.8 μm), CS 3700® (21.9 μm), CS 3600® (24.4 μm), VIRTUO VIVO® (32.0 μm), RUNEYES® (33.9 μm), EMERALD S® (36.8 μm), OMNICAM® (47.0 μm), EMERALD® (51.9 μm) and DWIO® (69.9 μm). Statistically significant differences were found between the IOSs. Linear and cross distances between the SBs (local trueness analysis) confirmed the data that emerged from the overall trueness evaluation.

CONCLUSIONS

Different levels of trueness were found among the IOSs evaluated in this study. Further studies are needed to confirm these results.

Monitoring Alveolar Ridge Remodelling Post-Extraction Using Sequential Intraoral Scanning over a Period of Four Months

The potential applications of computer-aided design/computer-aided manufacturing (CAD/CAM) and intraoral scanning exceed the delivery of standard prosthodontic interventions. The aim of this study was to clinically present a developed assessment technique, that relies on the use of sequential intraoral scanning, three-dimensional superimposition, and 2D and 3D deviation analyses based on a standardised protocol, as an auxiliary tool in monitoring dimensional changes of residual ridge post-extraction with a follow-up period of four months.

Digital maxillomandibular relationship registration for an edentulous maxilla: A dental technique

Recording the maxillomandibular relationship in a patient with an edentulous arch can be challenging in a completely digital workflow. A technique is presented that uses a scan of an existing removable prosthesis to align intraoral scans of the arches.

Does ambient light affect the accuracy and scanning time of intraoral scans?

STATEMENT OF PROBLEM

Intraoral scanners (IOSs) are based on light-optical imaging methods. However, little is known about whether the ambient light in dental practices influences the accuracy and scanning time of the IOS.

PURPOSE

The purpose of this in vitro study was to investigate the influence of different illuminations on the accuracy of 4-unit and complete-arch scans of 6 IOSs. In addition, the required scanning time was evaluated.

MATERIAL AND METHODS

A reference structure was attached to the first premolars (P) and second molars (M) in both quadrants (L/R) of a maxillary model. The resulting measured distances were M1-P1, M2-P2, P1-P2, and M1-M2. The investigation included 6 IOSs: TRIOS 3 (TRI), Cerec Omnicam (OC), iTero Element (ITE), CS 3600 (CS), Planmeca Emerald (EME), and GC Aadva (AAD). With each IOS, 17 scans at different illuminances (100, 500, 1000, and 5000 lux) were performed (N = 408). The precision and trueness for all distances were determined, and the scanning time was recorded. For statistical analyses, the Levene tests (precision) and 1-way analysis of variance with the post hoc Tukey honestly significant difference and Games-Howell tests (trueness) were calculated.

RESULTS

Illuminance significantly influenced the trueness of 4-unit scans for OC, EME, and AAD. TRI, OC, ITE, and CS demonstrated comparable results. AAD (>96 ±22 μm; 1000 lux) and EME (>248 ±88 μm; 500 lux) revealed greater deviations. For complete-arch scans, illuminance did not influence TRI and AAD, but significant variations were detected for ITE, CS, EME, and AAD. The least deviations were achieved with TRI and OC. The scanning time was extended for all IOSs except ITE at more than 500 lux. The shortest scanning times with OC and EME were recorded at 100 lux; with TRI, CS, and AAD at 500 lux; and with ITE at both 100 and 5000 lux. At all illuminances, the fastest scans were obtained with TRI.

CONCLUSIONS

Ambient light was found to influence the accuracy and scanning time of IOSs. This influence varies depending on the device. For 4-unit scans, the effect was not clinically relevant, but for complete-arch scans, accuracy and scanning time can be improved with appropriate lighting.

Clinical efficiency and patient preference of digital and conventional workflow for single implant crowns using immediate and regular digital impression: A meta-analysis

OBJECTIVE

To assess whether digital workflow gives better results than the conventional one in the single implant crowns, when analyzing the impression time, patient preference, time efficiency, and adjustment time.

MATERIAL AND METHODS

MEDLINE, Embase, and Cochrane were searched and supplemented via hand search up to June 19, 2019. Only clinical trials assessing conventional versus digital workflows for single implant crowns were included. Impression time was evaluated using random effects meta-analysis, while patient preference, adjustment time, and time efficiency were reported descriptively.

RESULTS

Among 1,334 publications identified, ten studies were included. The random effects models revealed statistically significant reduction in time in the digital impression group when compared to the conventional group by the mean meta-analysis (MD: 8.22 [95% CI: 5.48, 10.96]). Analysis from immediate digital impression versus conventional (MD: 3.84 [95% CI: 3.30, 4.39]) and regular digital impression versus conventional (MD:10.67 [95% CI: 5.70, 15.65]) showed statistically significant reduction in time on using the digital impression. Impression time in the digital process ranged between 6 min 39 s and 20 min, whereas for conventional, it was between 11.7 and 28.47 min. Patients showed greater preference for digital impression. Adjustment time in the digital process ranged between 1.96 and 14 min, whereas for conventional, it was between 3.02 and 12 min. Time efficiency in the digital process ranged between 36.8 and 185.4 min, whereas for conventional, it was between 55.6 and 332 min.

CONCLUSION

The digital workflow has demonstrated better clinical efficiency considering impression time, patient preference, and time efficiency. According to the adjustment time, different results were presented.