Complete Arch Research Articles

Reliability of the digital functionally generated path technique for assessing occlusal interferences and adjusting CAD-CAM zirconia crowns: an in vivo study

BackgroundDesigning the occlusal surface of a prosthesis to ensure optimal eccentric occlusion is challenging without precisely replicating the patient’s mandibular movements. During the CAD-CAM prosthesis delivery process, clinicians often need to make adjustments to the prosthesis to avoid occlusal interferences that may occur during lateral excursions. Recently, there have been developments in the field of mandibular motion tracking using optical devices. These approaches seek to incorporate an individual’s functional movement into the research field of occlusal morphology.AimThis study aimed to assess the accuracy of digitally replicating mandibular movements to identify and correct occlusal interferences in monolithic CAD-CAM zirconia crowns.MethodsAn intraoral scanner (IOS) was used to capture complete arch maxillary and mandibular teeth and record buccal and lateral interocclusal records of maxillary first premolar abutment teeth of thirteen participants. For each patient, two monolithic zirconia crowns were fabricated following the standard digital workflow. The crowns were categorized based on the virtual method used for adjusting occlusal interferences into two groups: Group I, where occlusal interferences in CAD-CAM zirconia crowns were adjusted using buccal interocclusal records, and Group II, where adjustments were made using both buccal and lateral interocclusal records. After crown fabrication following the manufacturer’s instructions, occlusion was analyzed using an electronic pressure analyzer. The mean, standard deviation and median values of the recorded data were measured. Paired t test and Wilcoxon Sign Rank test were executed for analyzing differences between groups (p value ≤ 0.05).ResultsGroup I recorded higher maximum pressure at lateral mandibular movement with mean ± standard deviation value of 26.00 ± 4.95% than Group II with 20.62 ± 3.38%. Regarding pressure recorded at maximum intercuspation (MI) Group I showed higher results; 8.08 ± 1.50% compared to Group II with 7.23 ± 1.59% mean ± standard deviation value. The average value of crown volume for Group I was (160.36 ± 15.94) mm3, while for Group II was (157.63 ± 14.45) mm3.ConclusionsThe digital functionally generated path technique allows for identifying occlusal interferences and modifying CAD-CAM zirconia crown designs.

Accuracy of Photogrammetry, Intraoral Scanning, and Conventional Impression for Multiple Implants: An InVitro Study.

This invitro study compared the accuracy of conventional impressions (CNVs), photogrammetry (PG), and intraoral scanning (IOS) for recording implant impressions of edentulous segments, ranging from part to complete arches by different evaluation methods. The master model for an edentulous maxillary arch was created with six implants (a-f). CNVs, PG, and IOS were used for impressions. Three impression ranges (bcde, bcdef, and abcdef) were chosen for analysis. The best-fit algorithm, absolute linear deviation, and angular deviation were used for evaluation. Trueness and precision were analyzed by two-way ANOVA and the Kruskal-Wallis test, respectively. The accuracy of multiple implant impressions was significantly influenced by the impression method and impression range (p < 0.05) regardless of the evaluation methods used. At smaller ranges (bcde and bcdef), there was no difference in the trueness of the three impression methods, whereas at a larger range (abcdef), both PG and CNV exhibited similar trueness, which was significantly higher than that of IOS(p < 0.05). The precision of PG was significantly better than that of CNV and IOS in most of cases (p < 0.05). As the range expanded, the trueness and precision of PG and IOS decreased (p < 0.05), whereas the accuracy of CNV remained stable. In the case of large-range impressions, PG demonstrated a similar degree of trueness and better precision compared with CNVs, whereas the trueness and precision of the intraoral scanning were worse. This indicated that PG might be a promising method for multiple implant impressions.

Management of Tricuspid Atresia With Normally Related Great Arteries and Left-Sided Obstruction.

Tricuspid atresia (TA) is the second most common form of functionally univentricular heart. For patients with TA and normally related great arteries (Type I), left ventricular outflow tract obstruction (LVOTO) is rare. From the Congenital Heart Surgeons' Society multi-institutional cohort of 445 patients with Type I TA enrolled from 1999 to 2024 from 42 sites, 14 infants (3%) had interventions for associated LVOTO, either at presentation or after their first TA-related intervention. Of seven infants initially undergoing Norwood/Damus-Kaye-Stansel (DKS), six survived to Stage II, of whom five survived with one developing pulmonary hypertension and four achieving Fontan. An additional seven infants who were first managed with pulmonary artery band placement subsequently had bidirectional superior cavopulmonary anastomosis (BCPA) and a DKS procedure; there were six survivors, all achieving Fontan. All ten survivors who underwent the Fontan procedure had normal left ventricular and mitral valve function at the latest follow-up. The overall Kaplan-Meier survival estimate at 20 years for these 14 patients was 79% (70% CI, 66%-88%), and the median follow-up was 8.3 years (0.24-21.5). While infants with TA and transposition of the great arteries are more likely to have LVOTO, this can also occur in the setting of normally related great arteries. Infants with Type I TA and LVOTO can be managed in the neonatal period with the Norwood procedure ensuring complete arch relief with acceptable outcomes. If LVOTO becomes evident after initial pulmonary artery band placement, a subsequent DKS procedure facilitates satisfactory success to Fontan.

Transitional implants in computer‐assisted implant surgery and fixed complete‐arch provisionalization: A retrospective case series

AbstractIntroductionUsing mini implants as transitional implants (TIs) for complete arch implant‐supported rehabilitations may overcome limitations associated with mucosa‐supported surgical guides and facilitate immediate fixed provisionalization. This study aimed to assess the success of TIs in supporting surgical guides for implant placement and fixed provisional prostheses.MethodsPatients who received TIs between 2012 and 2023 for a complete arch implant‐supported prosthesis were evaluated retrospectively. Patient demographic data, TI functionality in supporting a surgical guide and supporting a complete arch provisional prosthesis, and dates of TI placement and regular implant placement were collected. Descriptive statistics were used to determine the survival rate and success rate for TIs.ResultsTwenty‐six patients, 35 jaws, 136 TIs, and 216 regular implants were included. The survival rate of TIs was 74.26%; however, the use of TIs yielded success in 97% of jaws for supporting a surgical guide and a fixed complete‐arch provisional prosthesis throughout the complete provisional phase. An average of 4 TIs per maxilla and 3 TIs per mandible supported surgical guides. Thirty‐five provisional prostheses were placed on an average of 4 TIs in the maxilla and 3 TIs in the mandible. Thirty‐four provisional prostheses were successfully supported by TIs and regular implants until final restoration delivery. The survival of regular implants placed in conjunction with the use of TIs was 98%.ConclusionsUsing TIs to support a surgical guide and provisional prosthesis may be a predictable approach with a high success rate. All surgical guides planned to be supported on TIs were successful. Despite premature loss or replacement of TIs, this approach was able to support most provisional prostheses until the regular implants could be loaded.

Influence of the color of 3D-printed scan aids on the trueness of complete arch digital scans.

To determine the influence of using 3D-printed scan aids in varying colors on the trueness of digital scans. A master cast with five multi-unit analogues was scanned. The acquired dataset was exported to standard tessellation language (STL) file format to serve as the reference STL. 3D printing of the prototype in five distinct colors (beige [SABEIGE], grey [SAGREY], white [SAWHITE], red [SARED], and blue [SABLUE]) of polylactic acid filament was executed. The experimental STLs of each color group were aligned to the reference STL. RMS values were solely computed for the scan bodies. Based on the centers of the created best-fit and offset planes, scan bodies were converted into virtual cylinders. Cartesian coordinates of each cylinder were acquired. Subsequently, angular (AD) and linear deviation (LD) values were calculated. LD was further examined separately along the x, y, and z axes. Data were statistically analyzed. According to the results of one-way ANOVAs, significant differences were detected among color groups on AD, LD, RMS estimate error, ∆x, ∆y, and ∆z data. The lowest AD and LD values were exhibited by the SAGREY group in all implant sites. The SAGREY group was followed by the SABEIGE, SAWHITE, SARED, and SABLUE groups. The SAGREY outperformed the other groups in terms of trueness. Although the LD values of all color groups were below the threshold value (<100 µm), only the AD values of the SAGREY, SABEIGE, and SAWHITE groups were clinically acceptable (<0.5°).

An in-vitro study on accuracy of modular templates used to fully guide implants in combination with bone reduction for complete arch restorations: Experts versus students

ObjectivesThis in-vitro study evaluates the accuracy of modular surgical templates used to fully guide implants in combination with bone reduction, performed by expert and students, for complete arch restorations. MethodsAll the procedures were performed by dental students of the final year and an expert clinician, on twelve edentulous mandible models. A virtual implant planning, simulating a complete arch restoration on six implants were performed. Three different surgical guides were designed and printed to allow conventional fully guided implant placement (group 1); fully guided implant placement with modular guides (group 2); and fully guided implant placement after bone reduction, with similar, modular guides (group 3). After implant placement, optical scans of the study models were taken. Surface deviation and accuracy were evaluated and compared between groups and subgroups. ResultsA total of 12 surgical templates were used. Of these, Two templates in each group were used by two different students, while, the other six templates were used by an expert clinician as follows: one template with screwed anchor pins and one with pushed anchor pins in each group. A total of 72 implants were placed. Statistically significant difference was found between different template designs, when the implants were placed by an expert clinician. No statistically significant difference was found between expert and students, except the deviation in an angle value (students 2.13±1.46° versus expert 0.90±0.91°; P Value=0.0447) in the group 3. A statistically significant difference was found in favor of screwed anchor pins, in the group 1, in horizontal deviation (screwed pins 0.18±0.13 mm versus pushed pins 0.56±0.28 mm; P Value=0.0124; Table 5). No statistically significant difference was found between different template designs when the fully guided implants were placed by students, in both angle and horizontally (P=0.2787 and P=0.6601, respectively). A statistically significant difference was found between groups when the implants were placed by an expert clinician, with better value using screwed anchor pins, in the horizontal plane (P= 0.0293) but not in angle (P= 0.3380). ConclusionsModular templates provide a similar level of accuracy to conventional, one-piece guides. Screwed pins should be used to fix the base portion of the modular guides. Further clinical studies are needed to confirm these preliminary results. Clinical SignificanceModular surgical guides provide comparable accuracy to conventional, single-piece guides, however they offer more possibilities, helping in bone reduction and immediate loading procedures. Screwed anchor pins used to fix the base portion of the modular guides provide better final results than pushed pins.

Effect of build orientation on the fabrication trueness of additively manufactured implant-supported complete arch interim fixed prostheses.

To evaluate how build orientation affects the fabrication trueness of additively manufactured implant-supported complete arch prostheses by comparing them to subtractively manufactured high-impact polymer-based prostheses. An edentulous maxillary model with four implants at canine and first molar regions bilaterally was digitized (ATOS Core 80 5MP) to design a reference implant-supported complete arch prosthesis standard tessellation language file (RF-STL). The STL file was used to manufacture prostheses additively in five different orientations according to the build platform (AM-0, 0-degree; AM-15, 15-degree; AM-30, 30-degree; AM-45, 45-degree; AM-90, 90-degree) or subtractively (SM-HIP, control) (n = 10). The prostheses were digitized with an intraoral scanner (Trios 3) to generate their STLs (TF-STL). After superimposing TF-STLs over the RF-STL with a metrology-grade analysis software program (Geomagic Control X), surface deviations at four regions (overall, occlusal, overall without occlusal, and abutments), linear deviations at each abutment site, and interimplant distance deviations (canine-to-molar, canine-to-canine, and molar-to-molar) were calculated. One-way analysis of variance and Tukey HSD tests were used for the statistical analyses (α = 0.05). AM-90 mostly had the highest surface deviations, while AM-0 had the lowest overall, and lowest overall without occlusal region deviations (p ≤ 0.022). SM-HIP had the lowest occlusal region deviations (p < 0.001). AM-90 had the highest linear deviations (p < 0.001). AM-15 had higher canine-to-molar deviations than SM-HIP (p = 0.042). SM-HIP had the highest canine-to-canine deviations, while AM-90 had higher deviations than AM-0 and AM-30 (p ≤ 0.026). AM-45 and AM-90 had the highest and AM-0 had the lowest molar-to-molar deviations (p ≤ 0.013). AM-0 mostly had higher trueness and AM-90 mostly had lower trueness within tested outcomes. Additively manufactured prostheses mostly had lower canine-to-molar distances and higher molar-to-molar distances, whereas SM-HIP prostheses consistently had higher distances than the design file.

Clinical Outcomes of Full Arch Immediate Fixed Prostheses Supported By a Novel Implant System with Low Speed Site Preparation A 5 Years Retrospective Case Series

Background: The aim of this case series was to evaluate the 5-years clinical and radiographic outcomes of immediate full-arch fixed prosthesis supported by a novel implant system characterized by a low-speed site preparation protocol. Methods: Six medically compromised patients (3 females and 3 males) were consecutively enrolled and treated. Each patient received a fixed full-arch rehabilitations supported by two axial and two tilted implants. A total of 24 implants (N1 System, Nobel Biocare AB, Göteborg, Sweden) were placed in three mandibles and three maxillae using a low-speed drilling protocol with no irrigation. Prosthetic loading was applied within 2 hours of surgery, while then definitive restorations were placed 4 months later. Patients were scheduled for follow-up every 6 months up to 2 years and then annually. Radiographic evaluation of marginal bone level change was performed on regular intervals. Results: Between February 2019 and July 2019, six patients received a full-arch fixed prosthesis on four implants. All implants reached a minimum insertion torque of 30 Newton for immediate loading. After 5 years of observation (range 62-67 months), no implants failed and all definitive prostheses were stable and functional, resulting in a cumulative survival rate of 100%. After 5 years, the marginal bone loss was 1.46 ± 0.16 mm for the mandible and 1.85 ± 0.18 mm for the maxilla. Two implants (one axial and 1 tilted) in 1 patient treated in the maxillary arch reported more then 2 mm of marginal bone loss after 5 years. Conclusions: Within the limitations of this study, the successful medium-term results seem to confirm that immediate fixed full-arch rehabilitation, supported by two anterior axial and two posterior tilted implants, could be an effective and biologically beneficial treatment for complete arch edentulism. The reduced bone remodeling evidenced after 5 years of function confirm the biologically friendly concept behind this novel implant system.

Influence of repeated implant-abutment manipulation on the prevalence of peri-implant diseases in complete arch restorations. A retrospective analysis.

To evaluate the effects of repeated abutment manipulation on the prevalence of peri-implant diseases. A total of 27 edentulous patients (n = 108 implants) immediately restored with double-crown retained implant-supported prostheses were identified for this retrospective study. The test included the one-abutment, one-time care concept (n = 18 patients, n = 72 implants, OAOT) and the control abutment replacement (n = 9 patients, n = 36 implants, AR). A mixed effects model regression was conducted for the variable diagnosis (healthy, peri-implant mucositis, and peri-implantitis) with predictors abutment replacement (presence/absence), number of abutment replacement, category of keratinized mucosa (KM) (2 < KM ≥2 mm), and radiographic bone loss (BL). After 3-15 years (mean 10.2 ± 2.8 years), the prevalence of peri-implant mucositis and peri-implantitis in patients in the AR group was 11.1% and 88.9%, corresponding to 22.2% and 55.6% at the implant level, respectively. In OAOT group, none of the implants showed peri-implant mucositis, whereas the prevalence for peri-implantitis at patient and implant level amounted to 5.6% and 5.6%, respectively. The increased number of abutment replacements was significantly associated with the increased probability to diagnose peri-implant mucositis and peri-implantitis (OR: 6.13; 95% CI [2.61, 14.39]) (p < 0.001), whereas the presence of keratinized mucosa was not founded as a significant cofounder. The estimated mean BL in AR group was 1.38 mm larger than in OAOT group (p = 0.0190). The OAOT concept was associated with a lower prevalence of peri-implant diseases.

Digital workflow for complete arch immediate loading with a prefabricated interim prosthesis using autonomous robotic surgery: A dental technique

A fully digital workflow incorporating autonomous robotic surgery is described. A prefabricated interim prosthesis offers the potential to streamline the process and reduce chairside time. Adopting this digital workflow can simplify the treatment procedure and help minimize the overall time required for the provision of implant-supported prostheses.

In-Vitro Accuracy of Digital Versus Conventional Workflows for Complete Arch Implant Supported Frameworks - A Scoping Review.

Purpose: To investigate the available evidence on the accuracy of conventional and digital workflows for complete arch implant supported frameworks. Materials and methods: This scoping review was conducted according to the 5-stage framework of Arksey and O'Malley. A systematic literature search was performed adhering to the PRISMA guidelines to identify studies with a direct comparison of conventional and digital methods for the fabrication of complete arch implant supported frameworks. 58 in-vitro studies with the focus on edentulous arches with at least four implants published between 2000 and 2024 were included. The reported outcomes were examined to determine the value of a statistical analysis for adding up the individual errors to a cumulative error of the workflow. Results: Evidence on the accuracy assessment of digital and conventional workflows for complete arch implant supported frameworks is available. However, also studies with the same assessment methods and outcome units appear to be too heterogeneous to perform a statistical analysis of error accumulation. While there is no consensus in the impression and cast fabrication stage, digital techniques show a superior accuracy for the fabrication of complete arch implant supported frameworks compared to conventional casting. Conclusion: In-vitro studies assessing the accuracy of entire workflows and classifying their outcomes regarding the clinical relevance are lacking.

Complete-arch accuracy of seven intraoral scanners measured by the virtual-fit method

ObjectivesThis study compared the accuracy of seven intraoral scanners (IOS) by the virtual-fit method. MethodsFour maxillary arches with tooth abutments were scanned with an industrial reference scanner (n=1) and by Aoralscan3, EmeraldS, Helios600, Lumina, Mediti700, Primescan, and Trios5 IOSs (each n=12). Two complete-arch fixed frameworks were designed on each IOS scan with a 70 µm (group 70) and a 90 µm internal cement space (group 70+20, additional 20 µm at the margin). The virtual-fit method was comprised of superimposing the framework designs onto the reference scan using a non-penetrating algorithm simulating the clinical try-in. Internal and marginal gaps were measured. Precision was estimated by the mean absolute errors (MAE). ResultsIn group 70, Mediti700 (43 µm), Primescan (42 µm), and EmeraldS were in the best homogenous subset for the marginal gap, followed by the Lumina (67 µm), Aoralscan3 (70 µm), and Trios5 (70 µm), whereas Helios600 (118 µm) was in the third subset. Based on the MAE at the margin, Mediti700, Trios5, and EmeraldS were in the first-best homogenous subset, followed by Primescan. Lumina and Helios600 were in the third subset, and Aoralscan3 was in the fourth subset. In group 70+20, the marginal gap was significantly decreased for Lumina and Aoralscan3, whereas MAE significantly decreased for EmeraldS and Aoralscan3. The rank of IOSs was similar for the internal gap. ConclusionEmeraldS, Mediti700, Primescan, and Trios5 meet the marginal and internal fit criteria for fixed tooth-borne complete arch restorations. Increasing the cement space during design could enhance restoration fit. Clinical significanceThe virtual-fit alignment method can effectively evaluate the accuracy of different intraoral scanners, offering valuable clinical guidance for distinguishing among them. Recent software and hardware versions of long-standing IOS manufacturers are suitable for fabricating complete arch restoration.

3D-printed shell complete dentures as a diagnostic aid for implant planning and fabricating interim restorations for complete arch rehabilitations: A case series.

3D-printed shell complete dentures generated from a scan of the patient's existing prostheses can simplify and expedite the surgical planning and interim restoration design for complete arch rehabilitations. Three patients were rehabilitated with endosteal implants, and interim restorations were generated from the contours of the 3D-printed shell complete dentures used as diagnostic aids. This case series report presents the recommended protocol and its clinical progression, in addition to clinical and radiographic images of the treatment outcomes.

Accuracy of navigation guided implant surgery for immediate loading complete arch restorations: Prospective clinical trial.

To assess navigation accuracy for complete-arch implant placement with immediate loading of digitally prefabricated provisional. Consecutive edentulous and terminal dentition patients requiring at least one complete-arch FDP were treated between December 2020 and January 2022. Accuracy was evaluated by superimposing pre-operative and post-operative cone beam computed tomography (CBCT), recording linear (mm) and angular (degrees) deviations. T-tests were performed to investigate the potential effect of the registration algorithm (fiducial-based vs. fiducial-free), type of references for the fiducial-free algorithm (teeth vs. bone screws), site characteristic (healed vs. post-extractive), implant angulation (axial vs. tilted), type of arch (maxilla vs. mandible) on the accuracy with p-value <0.05. Twenty-five patients, 36 complete-arches, and 161 implants were placed. The overall mean angular deviation was 2.19° (SD 1.26°). The global platform and apex mean deviations were 1.17 mm (SD 0.57 mm), and 1.30 mm (SD 0.62 mm). Meaningful global platform (p = 0.0009) and apical (p = 0.0109) deviations were experienced only between healed and post-extraction sites. None of the analyzed variables significantly influenced angular deviation. Minor single-axis deviations were reported for the type of jaw (y-axis at implant platform and apex), registration algorithm (y-axis platform and z-axis deviations), and type of references for the fiducial-free algorithm. No statistically significant differences were found in relation to implant angulation. Within the study limitations navigation was reliable for complete-arch implant placement with immediate loading digitally pre-fabricated FDP. AI-driven surface anatomy identification and calibration protocol made fiducial-free registration as accurate as fiducial-based, teeth and bone screws equal as references. Implant site characteristics were the only statistically significant variable with healed sites reporting higher accuracy compared to post-extractive. Live-tracked navigation surgery enhanced operator performance and accuracy regardless of implant angulation and type of jaw. A mean safety room of about 1 mm and 2° should be considered.

Evaluation of accuracy of intra oral and extra oral complete arch scans on partially edentulous maxilla: An in vitro study

Evaluation of accuracy of intra oral and extra oral complete arch scans on partially edentulous maxilla: An in vitro study

TRUENESS AND PRECISION OF DIFFERENT DIGITAL SCAN SYSTEMS IN A TWO IMPLANT COMPLETE ARCH MODEL: AN IN-VITRO STUDY

Background: One of the major concerns in implant-retained prostheses is their accuracy which plays an essential role in implant success and prosthesis adaptation. Although many contemplates stated the indications and merits of different digital scanner systems, little is identified about their trueness and precision in scanning dental implants of implant-retained prostheses. Objectives: This contemplate aimed to evaluate and compare the trueness and precision of two unalike most recent digital scan systems in a mandibular two-implant complete arch model. Materials and Methods: A completely edentulous mandibular cast was utilized into which two conventional dental implant analogs were drilled in its inter-foramina area from which the distance between the analogs was measured by a caliper (Control). The same space was assessed via scanning the whole assembly 13 scans/each digital scanner system. The final distance of each scan attained from both systems was then compared with the control. The accuracy of each system was assessed in terms of trueness and precision. Results: Slight advancement of the Dof Freedom X5 premium digital scanner system than the Medit T300-T500 dental digital scanner regarding trueness although they were still insignificantly different, as P=0.66. The Medit digital scanner system was significantly better than the Dof Freedom one concerning precision, as P=0.001. Conclusion: The two dental laboratory digital scanner systems employed are reliable tools for scanning and reproducing digital dental records accurately for an implant-supported prosthesis. Furthermore, the Medit dental digital scanner system seemed to be more accurate in terms of precision than the Dof Freedom one.

Effect of preparation design and scan pattern on the accuracy of intraoral scans for complete arch laminate veneers under simulated intraoral variables.

The purpose of the study was to investigate the influence of different preparation designs and scan patterns on the accuracy of intraoral scans for complete-arch maxillary laminate veneers. Three maxillary typodonts were used to obtain reference models with three different laminate veneer preparation designs: windows (W), beveled (B), and incisal overlap (IO). Reference scans were obtained with a desktop scanner. A total of 90 complete arch intraoral scans were made with an intraoral scanner (Medit i700) following three different scan patterns: straight motion (SM), zigzag motion (ZM), and combined motion (CM). Ten scans were made in each subgroup and exported as standard tessellation language (STL) files. Assessment of accuracy was conducted with a 3D software analysis program (Geomagic Control X). Each STL file was individually aligned with the reference scan using the best fit algorithm tool, and 3D differences were calculated using the root mean square (RMS) value. Two-way analysis of variance (ANOVA) followed by post hoc comparison tests were applied to analyze precision and trueness data (α = 0.05). Two-way ANOVA and post hoc comparison tests revealed significant differences among different preparation designs and scan patterns (p < 0.05). Regarding trueness, the IO when scanned with SM presented higher mean RMS than the other preparation designs (W and B) scanned with the same scanning pattern (p < 0.05). Regarding precision, the groups of W and IO presented significantly higher mean RMS than the group of B when scanned with ZM (p < 0.05). Accuracy of intraoral scans for complete-arch laminate veneers was affected by different laminate veneer preparation designs and scan patterns. Modifying scan pattern according to preparation design helps to improve scan accuracy for complete-arch laminate veneers.

Enhancing Precision and Efficiency in Fabricating Complete Arch Screw-Retained Implant Prosthesis: A Clinical Case Report Utilizing the Nexus iOS Scan Gauge System.

Achieving an accurate fit in a complete arch screw-retained implant prosthesis is paramount, regardless of whether analog or digital impressions are employed. In the context of complete arch implant prostheses, using intraoral scanners has sparked significant debate. However, recent advancements in scanner technology, specialized scan gauges meticulously calibrated for precise recording, and the implementation of appropriate scanning techniques have substantially improved the precision and accuracy of digital records. The Nexus iOS scan gauge system represents a pioneering approach, seamlessly integrating these optimization strategies into a purely digital workflow to fabricate complete arch screw-retained implant prostheses in edentulous patients. This case report elucidates the fabrication process of a complete arch screw-retained implant prosthesis that exhibited remarkable fitting accuracy and streamlined the treatment process to a mere 3 appointments. The patient reported high satisfaction with the efficient timeline, aesthetic appeal, and functional performance of the prosthesis. A distinctive advantage of this technique is the notable reduction in treatment steps compared to traditional procedures.

Evaluating the influence of palate scanning on the accuracy of complete-arch digital impressions–An in vitro study

ObjectivesTo assess the impact of including the palate and the number of images recorded during intraoral digital scanning procedure on the accuracy of complete arch scans. MethodsAn experienced operator conducted 40 digital scans of a 3D printed maxillary model and divided them into two groups: 20 with inclusion of the palate (PAL) and 20 without (NPAL). Each set of scans was performed using an intraoral scanner (IOS) (Trios 5; 3Shape A/S; Copenhagen, Denmark). The resulting STL files were imported into the Geomagic Control X software (3D Systems, Rock Hill, SC, USA) for accuracy comparison. A reference STL file was created using a 3Shape E3 laboratory scanner (3Shape Scanlt Dental 2.2.1.0; Copenhagen, Denmark). The number of images captured was recorded during the scanning procedure. ResultsIn the case of the right side no statistically significant difference in trueness was detected (84 µm ± 45.6 for PAL and 80.4 ± 40.4 µm for NPAL). In the case of the left side no significant difference in trueness was observed (215.1 ± 70.2 µm for PAL and 233.9 ± 70.7 µm for NPAL). In the case of the arch distortion a statistically significant difference in trueness was seen between the two types of scans (135.3 ± 71.9 µm for PAL and 380.4 ± 255.1 µm for NPAL). The average number of images was 831.25, and 593.8 for PAL and NPAL, respectively. ConclusionsScanning of the palatal area can significantly improve the accuracy of dental scans in cases of complete arches. In terms of the number of images, based on the current results, obvious conclusions could not be drawn, and further investigation is required. Clinical significanceScanning the palate may be beneficial for improving the accuracy of intraoral scans in dentate patients. Consequently, this should be linked to an appropriate scanning strategy that predicts palatal scanning.

Effect of using scan body accessories and inter-implant distances on the accuracy of complete arch implant digital impressions: An in vitro study.

To introduce a novel design for scan body accessory parts that are reusable, easy to attach and detach without permanent change of the scan body, and can be used with different inter-implant distances to enhance the accuracy of complete arch implant scans. A maxillary polymethylmethacrylate (PMMA) model with a soft tissue replica was fabricated with four implant analogs located at tooth positions 17, 13, 22, and 27 with 18, 25, and 30mm inter-implant distances. Four scan bodies (SBs) were attached to the implants. The model was scanned with a laboratory scanner to be used as a reference scan. A total of 40 scans were made with the same intraoral scanner and they were divided equally into two groups. Group A: Complete arch implant scans without scan body accessories (n = 20), and Group B: Complete arch implant scans with scan body accessories (n = 20). Intraoral scans were exported and superimposed on the reference scan using reverse engineering inspection software to be evaluated for 3D deviations, angular deviations, and linear deviations. Statistical analysis was performed with student t-test and analysis of variance (ANOVA) with repeated measures followed by post hoc adjusted Bonferroni test. The level of significance was set at P = 0.05. The scan body accessories decreased both the 3D and linear deviations, with a statistically significant difference at SB4 for the 3D deviation (P = 0.043) and the linear inter-implant discrepancies between SB1-SB2 and SB3-SB4 (P = 0.029 and < 0.001), respectively. However, there was no statistically significant difference in angular deviation between the study groups. Implant positions had significant differences within each group. A significant improvement in the accuracy of the complete arch implant digital impression was achieved by using the scan body accessories, particularly in reducing the 3D and linear deviations at the most distant implant positions.