Full-Arch Implant Research Articles

Predictable and Precise Scanning Protocol for Full Arch Implant- Supported Immediate Prosthesis

Predictable and Precise Scanning Protocol for Full Arch Implant- Supported Immediate Prosthesis

Trueness of Extraoral Digital Impressions for Full-Arch Implant Impressions-In Vitro Study.

Direct scanning of silicone impressions is a valid technique. However, studies in implant-supported rehabilitations are lacking. This in vitro study aims to compare the trueness of impressions obtained with two types of silicone and their corresponding stone casts, using two laboratory scanners in a full-arch implant rehabilitation. A master cast with six dental implants was scanned with a 12-megapixel scanner to obtain a digital master cast. Ten implant impressions were made using two silicones (Zhermack and Coltene) with the open-tray technique. The impressions and stone casts were scanned by two extraoral scanners (Identica T500, Medit; and S600 ARTI, Zirkonzhan). Trueness was assessed by comparing linear and angular distances in digital casts with the master cast. A p < 0.05 significance level was considered. The results showed that for the linear measurements, 72% were higher than the master cast measurements, and no consistent pattern was observed in the angular measurements. The greatest deviations were detected between the most posterior implants, with mean values ranging between 173 and 314 µm. No significant differences were found between scanners. However, differences were observed in the distances between silicones (46.7%) and between impressions and stone casts (73.3%). This work demonstrates that the direct scanning of silicone impressions yields results comparable to those obtained from scanning gypsum casts in full-arch implant-supported rehabilitation.

Effect of a Novel ‘Scan Body’ on the In Vitro Scanning Accuracy of Full-Arch Implant Impressions

ObjectiveThis in vitro study aimed to determine whether a newly designed arcuate scan body can improve intraoral scanning accuracy for implant rehabilitation of edentulous jaws. Material and methodsA master model containing 4 implant abutment replicas was fabricated and digitized with different scan bodies using an intraoral scanner. Four types of scan bodies were evaluated: original scan bodies (group OS), computer-aided design and computer-aided manufacturing (CAD/CAM) scan bodies without extension (group CS), CAD/CAM scan bodies with straight extension (group CSS), and CAD/CAM scan bodies with arcuate extension (group CSA). Conventional splinted open-tray impressions (group CI) were used as controls. The master model and the poured casts were digitized using a laboratory scanner. Impressions were repeated 10 times each in 5 groups. Scans in standard tessellation language format were exported to reverse engineering software and root mean square (RMS) values were used for trueness and precision assessments. In each group, 45 RMS values were acquired for precision evaluation and 10 RMS values were obtained for trueness assessment. Statistical evaluation was performed with the Kruskal–Wallis test and Dunn–Bonferroni test (α = 0.05). ResultsThe median trueness values were 41.40, 55.95, 39.80, 39.75, and 22.30 μm for group OS, CS, CSS, CSA, and CI, respectively. CI showed better trueness than OS (P = .020), CS (P < .001), and CSS (P = .035). The median precisions for group OS, CS, CSS, CSA, and CI were 47.40, 51.50, 43.90, 25.20, and 24.60 μm. respectively. The precision of CSA and CI were higher than OS (P < .001), CS (P < .001), and CSS (P < .001). Between CI and CSA, there was no significant difference (P = 1.000). ConclusionsFor full-arch implant rehabilitation, the scan body with arcuate extension could improve the intraoral scanning precision and showed similar 3-dimensional discrepancy compared to conventional splinted open-tray impressions.

The Scalloped Surgical Guide as an Alternative to Flat Bone Reduction Guide in Full-arch Implant Restoration.

The goal of this clinical report was to present an alternative to traditional flat bone reduction guides, using a custom-designed 3D printed guide according to the future gingival margin of the planned dentition. A 61-year-old female with concerns regarding her smile appearance was presented. The initial examination revealed excessive gingival show accompanied by excessive overjet. The dentition was in a failing situation. The proposed treatment plan, relying on the sufficient amount of bone and keratinized tissue, consisted of re-contouring of the alveolar ridge and gingiva and placement of six implants and a FP-1 prosthesis after extraction of all remaining maxillary teeth. Digital smile design was completed, and a fully-digitally-guided surgery was planned. This consisted of utilizing three surgical guides. Starting with the fixation pin guide and continuing with the scalloped hard and soft tissue reduction guide and finally, the implant placement template. Following the surgery, the patient received a temporary restoration and on the 4-month follow-up, a new poly-methyl meta-acrylate temporary prosthesis was delivered. The patient's 7-month follow-up is presented in the paper. The report of this triple-template guided surgery indicated that digital 3D planning is a considerably predictable tool to properly establish and evaluate future occlusal plane, smile line, and lip support. Scalloped guides seem to be an excellent alternative to conventional bone reduction guides since they require less bone removal and improve patient comfort during surgery.

Efficient intraoral photogrammetry using self-identifying projective invariant marker.

The re-measurement of full-arch implant digital impressions is an important step in denture restoration. This paper provides an efficient oral photogrammetry technology using projective invariant marker, applied in the re-measurement of full-arch implant digital impressions. We have developed a self-recognizing marker with projection invariance, along with its detection code. The marker is installed on the scanning body and used for photogrammetric measurements. Triangulation is utilized to determine the 3D coordinates of the marker, followed by a series of post-processing steps to obtain more accurate 3D coordinates. The experimental data indicate that the optimal working distance is between 200 and 250mm, with a minimum measurement error of less than 0.05mm and an average measurement error of 0.10 mm. The measurement time is less than 2min. The experimental results show that the photogrammetric system can obtain reliable positions of full-arch implants with efficient photogrammetry, without the need to enter the patient's oral cavity, and has potential clinical application value.

Clinical and Radiographic Follow-Up of Full-Arch Implant Prosthetic Rehabilitations: Retrospective Clinical Study at 6-Year Follow-Up

Aim: the aim of this retrospective clinical study was to evaluate clinically and radiographically full-arch implant prosthetic rehabilitations supported by six axial implants or four implants placed according to the All-on-Four protocol. Materials and methods: Patients in need of immediately loaded full-arch implant prosthetic rehabilitations of one or both arches were considered. Follow-up visits were performed one week after surgery, at 3 and 6 months and then once a year for the next 6 years to record implant survival, peri-implant parameters, marginal bone loss, bone cortical thickness and possible muscular, articular and prosthetic complications. A satisfaction evaluation questionnaire was also made available to all patients at the end of the follow-up period. Results: A total of 30 patients with total edentulism of one or both arches or need for avulsion of residual impaired teeth were enrolled for this study and underwent implant prosthetic rehabilitation on four or six implants. The overall implant survival rate at the six-year follow-up was 98.09%. Statistical analysis revealed a significant association between implant site and higher plaque and bleeding index in the posterior site. The extent of keratinized tissue was statistically superior in anteriorly located implants. Statistical analysis showed a significant difference between the values of bone-marginal levels as a function of time. The vestibular and palatal/lingual bone cortices were preserved, with an increasing trend in the apical direction. Regarding muscular and articular complications, the results of this study showed statistically significant differences between the mean values recorded in male and female subjects, while the most frequently encountered problems during the clinical evaluation were the presence of joint clicks and pain in the masseter muscles. Two of the patients examined showed problems with mandibular latero-deviation and prosthetic fracture. Conclusion: within the limitations of the present study, immediate implant-retained prosthetic rehabilitations supported by six axial implants or four fixtures placed according to the All-on-Four method could represent a valid therapeutic alternative to provide edentulous patients with restoration of masticatory function and aesthetics and promote their acceptance.

EPA Consensus Project Paper: Accuracy of Photogrammetry Devices, Intraoral Scanners, and Conventional Techniques for the Full-Arch Implant Impressions: A Systematic Review.

The objective of this systematic review was to evaluate and compare the accuracy of digital impression techniques and conventional methods for full-arch implant impressions. An electronic literature search in the databases Medline (Pubmed), Web of Science, and Embase was performed to identify in vitro and in vivo publications (between 2016 and 2022) directly comparing digital and conventional abutment-level impression techniques. All selected articles passed through the data extraction procedure according to defined parameters in inclusion and exclusion criteria. Measurements on linear, angular and/or surface deviations were performed in all selected articles. Nine studies met the inclusion criteria and were selected for this systematic review. 3 articles were clinical studies and 6 studies were in vitro. Accuracy difference mean values of the trueness up to 162+/-77μm between digital and conventional techniques were reported in the clinical studies and up to 43μm in laboratory studies. Methodological heterogeneity was observed in both, in vivo and in vitro studies. Intraoral scanning and photogrammetric method showed comparable accuracy for registering implant positions in the full-arch edentulous cases. A tolerable implant prosthesis misfit threshold and objective misfit assessment criteria (for linear and angular deviations) should be verified in clinical studies.

Digital Workflow for Fully Guided Full-Arch Implant Reconstruction

Digital Workflow for Fully Guided Full-Arch Implant Reconstruction

EFFECT OF FRAMEWORK MATERIAL ON THE CLINICAL OUTCOMES OF FULL ARCH IMPLANT SUPPORTED PROSTHESES REMAINS UNQUANTIFIABLE.

Delucchi, F.; De Giovanni, E.; Pesce, P.; Bagnasco, F.; Pera, F.; Baldi, D.; Menini, M. Framework Materials for Full-Arch Implant-Supported Rehabilitations: A Systematic Review of Clinical Studies. Materials 2021, 14, 3251. https:// doi.org/10.3390/ma14123251 SOURCE OF FUNDING: This research received no funding. Systematic Review (SR).

Assessing the Impact of Resin Type, Post-Processing Technique, and Arch Location on the Trueness and Precision of 3D-Printed Full-Arch Implant Surgical Guides

Objective: The purpose of this study was to assess the impact of photopolymer resin type, arch location, and post-processing techniques on the trueness and precision of three-dimensionally printed (3DP) full-arch surgical implant guides. Methods: Stereolithography reference images of an upper and lower surgical guide with six drill holes from a full-mouth rehabilitation clinical case were used. The files were imported into the Asiga MAX UV slicing software (Asiga Composer) where build orientation, print resolution, and support structures were added. A digital light processing 3D printer (MAX UV, Asiga Max) was used for printing the samples. The samples assessed were printed using two different, manufacturer-validated resins, DentaGuide (n = 35) and DentaClear (n = 20). The samples were subdivided and measured based on the post-processing technique used: handwashing (n = 20), sonication (n = 25), a mix of handwashing and sonication (n = 10), and post-curing using 385 nm UVA light with nitrogen (n = 50) or without nitrogen (n = 5). The diameter of each drill hole per guide was measured using a coordinate measuring machine (Absolute Arm 7-Axis, Hexagon) and compared with the reference STL to calculate each sample’s trueness (median error) and precision (interquartile range). The Mann–Whitney and Kruskal–Wallis tests were used for statistical analyses. Results: All samples demonstrated a dimensional error of &lt;70 µm. No significant differences (p &gt; 0.05) were observed between upper and lower arches and between post-processing techniques using nitrogen, irrespective of the use of hand- or ultrasonic washing. In contrast, DentaClear resin was significantly (p &lt; 0.001) more accurate with a trueness of 26 µm and precision of 12 to 34 µm versus the DentaGuide at −31 µm and −54 to −17 µm, respectively. The samples post-cured without nitrogen were significantly (p &lt; 0.05) the least accurate of all surgical guides, with a trueness of −42 µm and precision of −68 to −39 µm. Conclusion: The resin type and nitrogen post-processing are parameters that can significantly impact the accuracy of surgical guides. The tolerance of 3DP surgical guides needs to account for the dimensional changes occurring during the manufacturing process to minimise implant positioning errors.

Volumetric Evaluations of Full-Arch Implant Supported Restorations and Their Role on Patients’ Quality of Life: A Mixed-Model Analysis

Introduction Full-arch, implant-supported hybrid restorations, employing tilted implants, can offer an efficient way of treating edentulous patients. Several factors, such as the timing of implant placement and the inclination of the fixture, can have a detrimental effect on their stability. This retrospective study is aimed at discerning the role played by those factors. Materials and Methods Patients treated with full-arch, implant supported restorations were selected for this study; cone-beam computed tomography (CBCT) images, taken 3 months and 3 years after delivery of the final restoration, as well as peri-implant values, were obtained and compared; bone loss was measured on four sites for each implant and then averaged. These patients were recalled, and the OHIP-5 questionnaire was administered. Results 21 patients, with a mean age of 53 years, were included in the present analysis. 108 implants were placed, and 25 Toronto prostheses were delivered. According to a mixed-model analysis, tilted implants (0.51, p < 0.001) had a higher rate of bone loss, while implants placed in a healed ridge suffered less bone loss than immediate implants (-0.21, p < 0.001). Patient-level variables have a significant effect on this variable, as implants coming from the same subject share a similar risk of bone loss. The mean response to the self-administered OHIP-5 questionnaire was 1.53 ± 0.29; other variables did not have a statistically significant effect on this outcome. Discussion/Conclusions. The results of the present study show that Toronto bridges prostheses are an efficient procedure for treating edentulous patients, as their oral-related quality of life is reported as satisfactory even 7 years after delivery of the restoration. Tilted and immediate implants are more at risk of bone loss. Implants coming from the same subject share a similar risk of bone loss.

Computer-Guided Immediate Full-Arch Implant Reconstruction of the Mandible in Severe Periodontally Compromised Patients: Three-Dimensional Analysis of Bone Volume Changes.

Comprehensive rehabilitation in patients with severe periodontal destruction may require the use of dental implants. The primary aim of this study was to evaluate bone volume changes in periodontally compromised patients over a 12-month follow-up period after immediate full-arch implant reconstruction of the mandible. The secondary aim was to evaluate the repeatability of 3D bone volume change measurement methods around dental implants. The null hypothesis was that bone volume would decrease in the first year after delivery of the definitive prosthetic reconstruction. This retrospective study analyzed CBCT scans of 16 patients before and after computer-guided immediate full-arch implant reconstruction of the mandible. The bone volume change in the mandibular body and around the implants and the peri-implant bone area in coronal and axial cross sections were calculated. The average bone gain for the mandibular body was 3.3% ± 1.8%. The average bone volume increase in the peri-implant area was 23.2% ± 16.7%. The interobserver and intraobserver ICC values for 3D measurements were high (> 0.85). The null hypothesis was rejected. Both mandibular body and peri-implant surroundings undergo bone remodeling in the form of bone gain over 12 months after immediate implantation.

Complete Digital Workflow for Mandibular Full-Arch Implant Rehabilitation in 3 Appointments.

The aim of this clinical report is to describe a complete digital workflow protocol for mandibular full-arch implant rehabilitation from guided surgery to definitive prosthesis in only 3 appointments. This expedited protocol allows for guided implant placement with a system of stackable surgical templates and CAD/CAM prosthodontic rehabilitation using a digital workflow. At the first appointment, a guided implant placement protocol with the stackable template concept was done followed by immediate loading with a prefabricated interim prosthesis. At the same appointment, the Double Digital Scanning (DDS) technique was used for scanning, maxillomandibular relationship registration and virtual articulation. The anchor pins from guided surgery were used as fiducial markers for DDS data superimposition. At the second appointment, the prosthesis prototype was tried-in and adjustments were made. At the third appointment, the definitive monolithic zirconia full-arch prosthesis was delivered.

Accuracy Evaluation of 14 Maxillary Full Arch Implant Treatments Performed with Da Vinci Bridge: A Case Series.

The use of pterygoid implants can be an attractive alternative to sinus bone grafting in the treatment of posterior atrophic maxilla. This technique has not been widely used because of the difficulty of the surgical access, the presence of vital structures, and the prosthetic challenges. The use of dynamic computer aided implantology (DCAI) allows the clinician to utilize navigation dental implant surgery, which allows the surgeon to follow the osteotomy site and implant positioning in real time. A total of 14 patients (28 pterygoid implants and 56 intersinusal implants) were enrolled in the study for a full arch implant prosthetic rehabilitation (4 frontal implants and 2 pterygoids implants), using a dynamic navigation system. The reported accuracy of pterygoid implants inserted using DCAI was 0.72 mm at coronal point, 1.25 mm at apical 3D, 0.66 mm at apical depth, and 2.86° as angular deviation. The use of pterygoid implants in lieu of bone grafting represents a valid treatment opportunity to carry out a safe, accurate, and minimally invasive surgery, while reducing treatment time and avoiding cantilevers for a full implant prosthetic rehabilitation of the upper arch.

A Study of Various Clinical Applications by Optical Impression Using an Intraoral Scanner : From the Optical Impression of the Full Arch Implant Case to the Production of Copy Denture

A Study of Various Clinical Applications by Optical Impression Using an Intraoral Scanner : From the Optical Impression of the Full Arch Implant Case to the Production of Copy Denture

The "Scalloped Guide": A Proof-of-Concept Technique for a Digitally Streamlined, Pink-Free Full-Arch Implant Protocol.

Inadequate restorative space can result in mechanical, biologic, and esthetic complications with full-arch fixed implant-supported prosthetics. As such, clinicians often reduce bone to create clearance. The aim of this paper was to present a protocol using stacking computer-aided design/computer-assisted manufacturing (CAD/CAM) guides to minimize and accurately obtain the desired bone reduction, immediately place prosthetically guided implants, and load a provisional that replicates predetermined tissue contour. This protocol can help clinicians minimize bone reduction and place the implants in an ideal position that allows them to emerge from the soft tissue interface with a natural, pink-free zirconia fixed dental prostheses.

A 3-D CAD/CAM technique in full-arch implant supported rehabilitations: the Virtual Implant-Prosthetic Procedure (VIPP Technique). A prospective longitudinal study

Aim. The purpose of this study is to evaluate the success of a new Three-Dimensional CAD/CAM processing technique in Full-Arch Implant Supported Rehabilitation of edentulous patients. Materials and Methods. Healthy patients with edentulous mandible and/or maxilla arch were selected for the present study. The Full-Arch Implant Supported Virtual Protocol has been applied with immediate loading fixed rehabilitation. Effectiveness of digital and surgical planning, marginal Bone Loss, Implant and Prosthetic failure were recorded at 6-and 12 months follow up. Results. 76 implants were placed in 15 patients, and 15 full arch rehabilitations were delivered. The patient found the smile design previsualization very effective (93%), the guided surgery very effective (94%), and the immediate loading and temporization very effective (92%). No implant were lost (survival rate = 100 %). At the 6-months radiographic evaluation, perimplant crestal bone loss averaged 0.56 ± 0.12 mm for maxillary implants (n = 64 implants), 0.59 ± 0.16 for mandibular implants (n = 12 implants) and 12-months perimplant crestal bone loss averaged 0.67 ± 0.11 mm for maxillary implants (n = 64 implants) and 0.69 ± 0.16 for mandibular implants (n = 12 implants) . Two unscrewing episodes and one provisional prosthesis fracture were detected. No paresthesia and no prosthetic complications in definitive prostheses were registered in the whole sample. Conclusions. Within these limitations, the present study reported that the Virtual Implant-Prosthetic Procedure could be a satisfactory treatment in edentulous patients.

Precision and Accuracy of a Digital Impression Scanner in Full-Arch Implant Rehabilitation.

To evaluate the accuracy and precision of a digital scanner used to scan four implants positioned according to an immediate loading implant protocol and to assess the accuracy of an aluminum framework fabricated from a digital impression. Five master casts reproducing different edentulous maxillae with four tilted implants were used. Four scan bodies were screwed onto the low-profile abutments, and a digital intraoral scanner was used to perform five digital impressions of each master cast. To assess trueness, a metal framework of the best digital impression was produced with computer-aided design/computer-assisted manufacture (CAD/CAM) technology and passive fit was assessed with the Sheffield test. Gaps between the frameworks and the implant analogs were measured with a stereomicroscope. To assess precision, three-dimensional (3D) point cloud processing software was used to measure the deviations between the five digital impressions of each cast by producing a color map. The deviation values were grouped in three classes, and differences were assessed between class 2 (representing lower discrepancies) and the assembled classes 1 and 3 (representing the higher negative and positive discrepancies, respectively). The frameworks showed a mean gap of < 30 μm (range: 2 to 47 μm). A statistically significant difference was found between the two groups by the 3D point cloud software, with higher frequencies of points in class 2 than in grouped classes 1 and 3 (P < .001). Within the limits of this in vitro study, it appears that a digital impression may represent a reliable method for fabricating full-arch implant frameworks with good passive fit when tilted implants are present.

Ceramic-Veneered Zirconia Frameworks in Full-Arch Implant Rehabilitations: A 6-Month to 5-Year Retrospective Cohort Study.

This was a retrospective cohort study designed to evaluate the clinical performance of ceramic-veneered zirconia frameworks. Patients were recruited according to defined inclusion criteria. All patients were checked every 4 months from the time of definitive rehabilitation. At the end of 2013, all patients were rescheduled and rechecked for study purposes. The restorative procedures assessment was performed by previously established methods. The primary outcomes were the survival and success rates of the prosthesis. Descriptive statistics were used for the patient's demographics, implant distribution, and occurrence of complications. To study the survival and success of the prostheses, a Cox Regression analysis was used with a model constructed in a forward conditional stepwise mode. Predictive variables were included in the model, and adjusted survival curves were obtained for each outcome. From 2008 to 2013, 75 patients were rehabilitated with 92 implant-supported, screw-retained, full-arch ceramic-veneered zirconia framework rehabilitations. The range of follow-up was between 6 months and 5 years. From the 92 full implant-supported screw-retained full-arch rehabilitations, Cox regression analysis indicated that within a 5-year time frame, the probability of framework fracture, major chipping, minor chipping, or any of the former combined to occur was 17.6%, 46.5%, 69.2%, and 90.5%, respectively. Results suggest zirconia as a suitable material for framework structure in implant-supported, full-arch rehabilitations. However, it experiences a high incidence of technical complications, mainly due to ceramic chipping. Further clinical studies should aim to ascertain the effects of clinical features and manufacturing procedures on the survival rates of these prostheses.

Graftless Full-Arch Implant Rehabilitation with Interantral Implants and Immediate or Delayed Loading-Part II: Transition from the Failing Maxillary Dentition.

To compare long-term survival and marginal bone loss of immediate interantral implants in the nonaugmented maxilla subjected to immediate vs delayed loading. Graftless maxillary cross-arch rehabilitation was performed in a total of 362 patients in the years 2004 to 2013 (1,797 implants). Of the 240 patients with immediate implants replacing their failing maxillary dentition, 81% were subjected to immediate loading and 19% to delayed loading of their 4 to 6 interantral implants (980 and 235 implants, respectively). Kaplan-Meier survival estimates were computed and marginal bone loss was evaluated in a stratified random sample of 20 patients per group. Thirty-one of 1,215 implants failed within the mean observation period of 3.9 years, and no difference in 8-year survival estimates could be seen between immediate (97.6% [95% CI: 96.7 to 98.6]) and delayed (96.6% [95% CI: 94.3 to 98.9]) loading protocols (P = .359). Mean marginal bone resorption following implant insertion did not differ significantly between the groups (1.5 ± 1.7 mm vs 0.7 ± 1.1 mm, P = .379); however, it was significantly associated with a reduced number of implants (P = .017) and patient history of periodontal disease (P < .001). Immediate loading of interantral implants yields satisfactory results in the transition of patients from a failing maxillary dentition to full-arch implant rehabilitation and thus may be favored over delayed loading concepts.