Implant Impressions Research Articles

Analysis of Strain and Temperature Induced by Acrylic Resins in Splinting Methods Used for Dental Implant Impressions

This study evaluates the polymerization shrinkage of two types of acrylic resins using two methods of splinting. Two implants were placed in an artificial bone, with the two transfer copings joined with dental floss and acrylic resins. Measurements of shrinkage and temperature were performed with fiber Bragg grating sensors. The results revealed that both resins showed similar shrinkage values, although one of them also showed a higher temperature increase. The measured values demonstrated that the separation and reconnection of the splinting with acrylic resin is effective at relaxing stress polymerization and reducing shrinkage polymerization.

Accuracy of digital impressions of multiple dental implants: an invitro study.

Studies demonstrated that the accuracy of intra-oral scanners can be compared with conventional impressions for most indications. However, little is known about their applicability to take impressions of multiple implants. The aim of this study was to evaluate the accuracy of four intra-oral scanners when applied for implant impressions in the edentulous jaw. An acrylic mandibular cast containing six external connection implants (region 36, 34, 32, 42, 44 and 46) with PEEK scanbodies was scanned using four intra-oral scanners: the Lava C.O.S. and the 3M True Definition, Cerec Omnicam and 3Shape Trios. Each model was scanned 10 times with every intra-oral scanner. As a reference, a highly accurate laboratory scanner (104i, Imetric, Courgenay, Switzerland) was used. The scans were imported into metrology software (Geomagic Qualify 12) for analyses. Accuracy was measured in terms of trueness (comparing test and reference) and precision (determining the deviation between different test scans). Mann-Whitney U-test and Wilcoxon signed rank test were used to detect statistically significant differences in trueness and precision respectively. The mean trueness was 0.112mm for Lava COS, 0.035mm for 3M TrueDef, 0.028mm for Trios and 0.061mm for Cerec Omnicam. There was no statistically significant difference between 3M TrueDef and Trios (P=0.262). Cerec Omnicam was less accurate than 3M TrueDef (P=0.013) and Trios (P=0.005), but more accurate compared to Lava COS (P=0.007). Lava COS was also less accurate compared to 3M TrueDef (P=0.005) and Trios (P=0.005). The mean precision was 0.066mm for Lava COS, 0.030mm for 3M TrueDef, 0.033mm for Trios and 0.059mm for Cerec Omnicam. There was no statistically significant difference between 3M TrueDef and Trios (P=0.119). Cerec Omnicam was less accurate compared to 3M TrueDef (P<0.001) and Trios (P<0.001), but no difference was found with Lava COS (P=0.169). Lava COS was also less accurate compared to 3M TrueDef (P<0.001) and Trios (P<0.001). Based on the findings of this invitro study, the 3M True Definition and Trios scanner demonstrated the highest accuracy. The Lava COS was found not suitable for taking implant impressions for a cross-arch bridge in the edentulous jaw.

Effects of Impression Coping Design, Impression Technique, and Dental Undercuts on the Accuracy of Implant Impressions Assessed by 3-Dimensional Optical Scanning: An In Vitro Study.

The aim of this in vitro study was to evaluate the effect of the type and design of the impression copings on the accuracy of implant impressions in 2 different conditions. A reference model with 2 implants inserted in bilateral mandibular canines was fabricated. The posterior teeth were inserted as tilted to simulate intra-oral undercuts. The teeth were eliminated to create an edentulous condition. Three different impression techniques were performed (open high retentive [OH], open low retentive [OL], closed [C]) for each condition. Total of 48 casts were made. Two scan-bodies were secured on each cast, scanned by an optical scanner. Then, they were compared to the scan of the reference model, and the calculated mean errors were analyzed with a 2-way ANOVA and Tukey test. There was no significant difference between the complete and partially edentulous groups (F = 3.252, P = 0.079). There was significant difference between the different designs of the impression copings (F = 31.789, P < 0.001) but the interaction between the dependent variables was not significant (F = 0.511, P = 0.603). The design of the impression copings was more important than the undercuts. The accuracy of the closed tray coping was greater than the low retentive coping and equal to the high retentive coping.

Effect of Impla Fix and Duralay Acrylic Resin Splinting Materials on Dimensional Changes of Direct Implant Impressions

Effect of Impla Fix and Duralay Acrylic Resin Splinting Materials on Dimensional Changes of Direct Implant Impressions

Clinical Assessment of Two Modified Implant Impression Copings by means of Visual Analog Scale

Clinical Assessment of Two Modified Implant Impression Copings by means of Visual Analog Scale

Digital implant impressions by cone-beam computerized tomography: a pilot study.

To evaluate the adjustment of structures designed from a digital impression of implants obtained by cone-beam computerized tomography (CBCT). Thirty implants were placed in five edentulous mandibles of fresh cadaver heads, six per mandible. Special scan bodies were screwed in the implants and a CBCT was taken. DICOM images were converted to STL and digitally processed to obtain a digital model of the implants. A Cr-Co structure was designed and milled for each mandible, and the adjustment was assessed as in a real clinical situation: passivity while screwing, radiographic fitting, optical fitting, and probing. Good adjustment was found in three of the structures, and only slight discrepancies were found in the other two. Cone-beam computerized tomography might be a valid impression-taking method in full-mouth rehabilitations with implants. Further evaluations are needed with more implant and CBCT systems. The radiation dose might be considered when deciding to use this impression system. The types of patients appropriate for this treatment option should also be determined to fulfill the principles of the ALARA law.

A Novel Method to Evaluate Precision of Optical Implant Impressions with Commercial Scan Bodies-An Experimental Approach.

Optical transfer is realized with system-specific transfer posts (scan bodies) mounted on dental implants or on implant analogs. This study presents a novel algorithm for creation of geometry on the surface of dental implant scan bodies and examines the precision of the optical acquisition of scan bodies and the precision of the position of the screw-tightened scan bodies on dental implant analogs. Scan bodies of two different implant manufacturers (S1, S2), one with a horizontal and two with different conical implant-abutment geometries were screw tightened to implant analogs in stone casts with a 10 Ncm torque. The stone casts were scanned ten times with a dental lab scanner. Each scan body was removed and positioned ten times; after each repositioning, a scan was performed. The cylinder axis of every scan body and the occlusal horizontal scan body surface was virtually reconstructed. At the intersection of the cylinder axis and the horizontal plane a point was marked. The mean deviation of this point in consecutive scans and the angle between the scan body axes in the virtual models were measured, and the standard deviation was calculated. Statistical significance of the results was tested with a Kruskal-Wallis Test and Mann-Whitney U-test for pairwise comparison (p < 0.05). The mean deviation of the angle between two scan bodies was 0.05° (SD 0.04°) (S1) and 0.14° (SD 0.08°) (S2). After detachment and repositioning of the scan bodies the mean deviation was 0.05° (SD 0.03°) (S1) and 0.16° (SD 0.08°) (S2). The mean deviation of the central point was 5.7 μm (SD 3.4 μm) without detachment and 4.9 μm (SD 2.6 μm) after detachment and repositioning (S1). For system S2 the mean deviation of the central point was 13.4 μm (SD 7.2 μm) after repeated scanning and 15 μm (SD 5 μm) after detachment, repositioning, and repeated scanning. The precision of extraoral scanning of scan bodies is dependent on the scan body surface design and geometry. The precision of scanning with an extraoral model scanner differed between the scan body geometries and inter-scan body distances. The precision of dental implant scan body scanning was not significantly influenced by detachment and repositioning of the scan body.

Accuracy of interchangeable implant impression systems: an in vitro pilot study.

To evaluate the accuracy of impressions on changing the implant component (coping and abutment replica) between Brånemark and BIOMET 3i and between Straumann and Allfit. Two master casts were constructed, one containing pair of Brånemark self-tap Mk II fixtures (Nobel Biocare) labeled Master cast I and the other containing pair of Straumann Standard plus implant, SLA fixtures (Straumann) labeled Master cast II. Ten impressions of each master cast were made by open tray technique using polyether impression material. Five out of 10 impressions made from master cast I contained Brånemark pair of coping and replica and the other 5 contained 3i (Implant Innovations). Five out of 10 impressions made from master cast II contained Straumann pair of copings and replica and the remaining 5 contained Allfit implants (Ihde Dental). Duplicated casts were prepared, and distances between copings were measured using traveling microscope and compared the distance in master casts. No significant difference was observed in mean value between 2 master casts and their duplicates. The interchangeability of coping and abutment replica between Brånemark and BIOMET 3i and between Straumann and Allfit was found to be possible without compromising the quality of impressions.

Effect of implant angulation and impression technique on impressions of NobelActive implants

Statement of problemHow the configuration of the NobelActive internal conical connection affects implant impressions is uncertain. PurposeThe purpose of this study was to measure the effect in vitro of closed and open tray impression techniques for NobelActive implants placed at various angulations. Material and methodsSix NobelActive implants were placed in a master maxillary cast as follows: 0 degrees of angulation to a line drawn perpendicular to the occlusal plane in the first molar area, 15 degrees of angulation to a line drawn perpendicular to the occlusal plane in the first premolar area, and 30 degrees of angulation to a line drawn perpendicular to the occlusal plane in the lateral incisor area. Twelve open tray and 12 closed tray impressions were made. Occlusal, lateral, and frontal view photographs of the resulting casts were used to measure the linear and angular displacement of implant analogs. Statistical analysis was performed with a factorial analysis of variance (ANOVA), followed by the Tukey HSD test (α=.05). ResultsNo significant difference was found in the impressions made of NobelActive implants with the open or closed tray technique (linear displacement: F=0.93, P=.34; angular displacement: F=2.09, P=.15). In addition, implant angulation (0, 15, or 30 degrees) had no effect on the linear or angular displacement of impressions (linear displacement: F=2.72, P=.07; angular displacement: F=0.86, P=.43). Finally, no significant interaction was found between impression technique and implant angulation on NobelActive implants (F=0.25, P=.77; F=1.60, P=.20). ConclusionsWithin the limitations of this study, impression technique (open vs closed tray) and implant angulation (0, 15, and 30 degrees) had no significant effect on in vitro impressions of NobelActive implants.

Accuracy of two digital implant impression systems based on confocal microscopy with variations in customized software and clinical parameters.

To evaluate the accuracy of two digital impression systems based on the same technology but different postprocessing correction modes of customized software, with consideration of several clinical parameters. A maxillary master model with six implants located in the second molar, second premolar, and lateral incisor positions was fitted with six cylindrical scan bodies. Scan bodies were placed at different angulations or depths apical to the gingiva. Two experienced and two inexperienced operators performed scans with either 3D Progress (MHT) or ZFX Intrascan (Zimmer Dental). Five different distances between implants (scan bodies) were measured, yielding five data points per impression and 100 per impression system. Measurements made with a high-accuracy three-dimensional coordinate measuring machine (CMM) of the master model acted as the true values. The values obtained from the digital impressions were subtracted from the CMM values to identify the deviations. The differences between experienced and inexperienced operators and implant angulation and depth were compared statistically. Experience of the operator, implant angulation, and implant depth were not associated with significant differences in deviation from the true values with both 3D Progress and ZFX Intrascan. Accuracy in the first scanned quadrant was significantly better with 3D Progress, but ZFX Intrascan presented better accuracy in the full arch. Neither of the two systems tested would be suitable for digital impression of multiple-implant prostheses. Because of the errors, further development of both systems is required.

Accuracy of impressions of multiple implants in the edentulous arch: a systematic review.

Because there is a paucity of clear-cut evidence regarding which materials and techniques are most accurate for complete-arch, multiple-implant impressions, the current study sought to analyze the data and draw useful conclusions based on the evidence for application in clinical practice. Relevant studies published between 1990 and December 2012 were included in the review. The articles were located through PubMed and manually through reviewing references in the literature. Papers examining implant impression accuracy in completely edentulous arches (three or more implants) were included. Clinical case reports, technique articles, abstracts, and review papers were excluded. One of the 34 studies selected for evaluation was clinical; the remaining 33 were in vitro investigations. Ten studies compared polyvinyl siloxane (PVS) and polyether (PE); eight found that these were statistically equal in terms of impression accuracy. The splint effect was examined by 24 studies; 10 failed to observe any differences between splinted and nonsplinted impressions, whereas 7 (> 25%) showed that the splinted technique was better than the nonsplinted technique. Thirteen studies investigated the differences between pickup and transfer impression techniques; six favored pickup over transfer, and five found insignificant differences between the techniques. The effect of nonparallel implants on edentulous multiple-implant impression accuracy was examined by only two studies. Significant differences in accuracy were observed for 15 degrees of angulation. Most of the evidence supports PVS and PE as the most accurate impression materials for edentulous multiple-implant situations, with no clear advantage of either. Conflicting evidence exists regarding the most accurate impression technique (splinted/nonsplinted, pickup/transfer), and no clear recommendation can be made. Inadequate research exists regarding several other factors that might affect edentulous implant impression accuracy. There is a lack of clinical research to support in vitro findings.

Does Steam Autoclaving Affect the Accuracy of Implant Impression Systems?

Does Steam Autoclaving Affect the Accuracy of Implant Impression Systems?

Comparative evaluation of the accuracy of pick up transfer impressions performed with two different types of trays

The success of implant-supported prostheses is related to the passive union between the prostheses’ connections and the implants, so it is necessary to obtain an accurate working cast. Objective: To evaluate the accuracy of the transfer impressions of implants performed with individual acrylic resin trays and conventional trays using polyvinyl siloxane. Material and methods: To carry out the transfer impressions, a master cast with four external hexagon implants parallel to each other was used. Five impressions were made with individual acrylic resin trays and five other impressions with modified conventional trays, opened in the region of the implants. The linear measurements between the implants were made with a digital caliper with an accuracy of 0.01 mm and the results were statistically evaluated �(alpha = 5%)�. Results: For the points AB and BC, the measurements obtained with the individual trays were statistically similar to the master cast. For the points CD and DA no statistical differences among the three groups were observed. Conclusion: Given the obtained results and the methodology used, it can be concluded that the impressions performed with individual trays presented higher accuracy compared to the ones obtained with conventional trays.

Using stereophotogrammetric technology for obtaining intraoral digital impressions of implants

The procedure for making impressions of multiple implants continues to be a challenge, despite the various techniques proposed to date. The authors' objective in this case report is to describe a novel digital impression method for multiple implants involving the use of stereophotogrammetric technology. The authors present three cases of patients who had multiple implants in which the impressions were obtained with this technology. Initially, a stereo camera with an infrared flash detects the position of special flag abutments screwed into the implants. This process is based on registering the x, y and z coordinates of each implant and the distances between them. This information is converted into a stereolithographic (STL) file. To add the soft-tissue information, the user must obtain another STL file by using an intraoral or extraoral scanner. In the first case presented, this information was acquired from the plaster model with an extraoral scanner; in the second case, from a Digital Imaging and Communication in Medicine (DICOM) file of the plaster model obtained with cone-beam computed tomography; and in the third case, through an intraoral digital impression with a confocal scanner. In the three cases, the frameworks manufactured from this technique showed a correct clinical passive fit. At follow-up appointments held six, 12 and 24 months after insertion of the prosthesis, no complications were reported. Stereophotogrammetric technology is a viable, accurate and easy technique for making multiple implant impressions. Clinicians can use stereophotogrammetric technology to acquire reliable digital master models as a first step in producing frameworks with a correct passive fit.

Comparative Evaluation of Impression Accuracy of Tilted and Straight Implants in All-on-Four Technique

The aim of this in vitro study was to compare the accuracy of implant impressions in parallel and nonparallel implants of All-on-Four treatment plan. A reference model containing 4 internal-connection implant analogs was fabricated according to All-on-Four treatment plan (2 anterior implants at 0 degree and 2 posterior implants at 30 degrees in relation to the perpendicular line). Twenty impressions of this model were made using open-tray impression technique. Impressions were poured with American Dental Association type 4 stone, and the positional accuracy of the implant replica heads in x-, y-, and z- axes was evaluated using a coordinate measuring machine. These measurements were compared with the obtained measurements from the reference model that served as control, and data were analyzed using independent test (α = 0.05). The results showed that the accuracy of the implant impressions did not show any significant difference between the tilted and straight implants except in y-coordinate (P = 0.012). Within the limitations of this study, the accuracy of the implant impressions did not differ for different implant angulations in All-on-Four treatment plan.

Comparison of Accuracy of Direct Implant Impression Technique using Different Splinting Materials

ABSTRACT Introduction The accuracy of an impression remains critical factor in achieving passive fit of an implant framework. The accuracy of the master cast would depend on the type of impression material, the implant impression technique and accuracy of die material. The different impression techniques advocated in the literature for implant impressions include direct (open tray) and indirect (closed tray) techniques. Direct technique use square impression copings that are picked up in the impressions which were used in this study. Objective To evaluate the accuracy of direct impression made with resin splinted and bis-GMA splinted open-tray impression coping. Thus to compare the accuracy of impressions obtained using different splinting materials. Materials and Methods A wax mandibular reference model was fabricated and four implants were placed in the mandibular anterior region using surveyor and acrylized with clear heat cure acrylic resin using injection molding technique. Spaced primary cast was fabricated with a uniform thickness of space about 2 mm. Ten custom trays were fabricated using the light curable resin sheets. Medium body polyether impression material was used. Pentamix was used to get a uniform mix. These trays were randomly divided among the two groups, with five trays in each group. Impression techniques were divided into two groups namely: Group A - direct impression technique with open tray impression copings splinted with autopolymerizing acrylic resin (GC pattern resin), group B - direct impression technique with open tray impression copings splinted with Protemp TM4 (bis- GMA) syringable temporisation material. Thus, final impressions were made. Total of 10 master casts were fabricated. Evaluation of casts using Dynascope-Vision engineering, Tesa Microhite 2D and coordinate measuring machine were used. Results Statistical comparisons were made using ANOVA test and post-hoc test. Same amount of deviation values obtained with resin splinted and bis-GMA splinted impression copings. The difference in the values might be because of the variation in the rigidity of the materials used. Conclusion Both the splinting material exhibit similar accuracy in impression, so bis-GMA can be used, which is easy to handle, less time consuming, less technique sensitive, rigid and readily available material in clinics, instead of resin splinted material which is technique sensitive, more time consuming and cumbersome. How to cite this article Selvaraj S, Mohan J, Simon P, Dorairaj J. Comparison of Accuracy of Direct Implant Impression Technique using Different Splinting Materials. Int J Prosthodont Restor Dent 2014;4(3):82-89.

Impression of multiple implants using photogrammetry: Description of technique and case presentation

Aim: To describe a technique for registering the positions of multiple dental implants using a system based on photogrammetry. A case is presented in which a prosthetic treatment was performed using this technique. Study Design: Three Euroteknika® dental implants were placed to rehabilitate a 55-year-old male patient with right posterior maxillary edentulism. Three months later, the positions of the implants were registered using a photogrammetry-based stereo-camera (PICcamera®). After processing patient and implant data, special abutments (PICabutment®) were screwed onto each implant. The PICcamera® was then used to capture images of the implant positions, automatically taking 150 images in less than 60 seconds. From this information a file was obtained describing the relative positions – angles and distances – of each implant in vector form. Information regarding the soft tissues was obtained from an alginate impression that was cast in plaster and scanned. A Cr-Co structure was obtained using CAD/CAM, and its passive fit was verified in the patient’s mouth using the Sheffield test and the screw resistance test. Results and Conclusions: Twelve months after loading, peri-implant tissues were healthy and no marginal bone loss was observed. The clinical application of this new system using photogrammetry to record the position of multiple dental implants facilitated the rehabilitation of a patient with posterior maxillary edentulism by means of a prosthesis with optimal fit. The prosthetic process was accurate, fast, simple to apply and comfortable for the patient. Key words:Dental implants, photogrammetry, dental impression technique, CAD/CAM.

A Clinical Protocol for Intraoral Digital Impression of Screw-Retained CAD/CAM Framework on Multiple Implants Based on Wavefront Sampling Technology

To obtain an accurate CAD/CAM metal framework over 6 implants using a Chairside Intraoral Scanner based on the principle of active (optical) wavefront sampling. Six prototype cylindrical scan bodies screwed in the implants were used to obtain an intraoral digital impression. A conventional resin tooth try-in was fabricated and digitized with an extraoral scanner, and this dataset was merged to the digital data obtained from the intraoral impression to calculate the best framework design with advanced CAD software. The framework was fabricated with a 5-axis computer numerical control milling unit. Three clinical tests (saliva intrusion, Sheffield test, and screw resistance test) were performed to assess the fit of the framework. Under 3 clinical tests, an accurate fit was observed. The case presented in this report proposes a new clinical protocol for obtaining accurate digital impressions of multiple implants.

Accuracy of a Digital Impression System Based on Active Wavefront Sampling Technology for Implants Considering Operator Experience, Implant Angulation, and Depth

There is a scarce knowledge on the accuracy of intraoral digital impression systems for dental implants. The purpose of this study is to evaluate the accuracy of a digital impression system considering clinical parameters. A master model with six implants (27, 25, 22, 12, 15, 17) was fitted with polyether ether ketone scan bodies. Implant no. 25 was placed with 30° mesial angulation in relation to the vertical plane (y axis), and implant no. 15 was positioned with 30° distal angulation. Implant no. 22 was placed 2 mm and no. 12, 4 mm below the gingiva. Experienced (n = 2) and inexperienced operators (n = 2) performed scanning (Lava Chairside Oral Scanner; 3 M ESPE, St Paul, MN, USA) at standard and high accuracy mode. Measurements involved five distances (27-25, 27-22, 27-12, 27-15, 27-17). Measurements with high accuracy three-dimensional coordinated measuring machine (CMM) of the master model acted as the true values. The data obtained were subtracted from those of the CMM values. Experience of the operator significantly influenced the results (p = .000). Angulation (p = .195) and depth of implant (p = .399) did not show significant deviation from the true values. The mean difference between standard and high accuracy mode was 90 μm. With the active wavefront sampling, technology-based digital impression system training seems to be compulsory. Impressions of angulated implants may diminish the accuracy of the impression, yet the results were not significant.

FULL-ARCH MAXILLARY REHABILITATION FIXED ON 6 IMPLANTS

The purpose of this study is to report a case of full-arch rehabilitation on six endosseous implants loaded following the standard procedure. An implant-prosthetic treatment was proposed to a 53-year-old woman with a total prosthesis in the upper jaw. Six implants on upper maxillary were placed keeping the upper complete denture during the osseointegration period. The implants were left submerged to allow the patient to wear removable prostheses and the prosthesis was rebase with Hydrocast to not compress the sites of healing during the osseointegration period. The impression of implants was made with silicones for addition (VPS) with different viscosities after 8 weeks. The final restoration was carried out taking into account the aesthetic and functional canons. Correct diagnosis and accurate implant planning are key for success in implant rehabilitation.