Effect of auxiliary geometric devices on the accuracy of intraoral scans in full-arch implant-supported rehabilitations: An in vitro study.

OBJECTIVES: The aim of the present in vitro study was to evaluate the effect of a novel auxiliary geometric device (AGD) on the accuracy of full-arch scans captured with 3 different intraoral scanners (IOS). METHODS: An edentulous maxillary model with four internal connection implant replicas was scanned using 3 different IOS: iTero Element 5D (ITERO) (Align Technology, Tempe, AZ, USA), Trios 4 (TRIOS) (3Shape A/S, Copenhagen, Denmark), and Carestream 3700 (CS) (Carestream Dental, Atlanta, USA). Thirty-six scans were taken with each IOS, 18 with the AGD in place, and 18 without the AGD. A digital master model was created using an industrial optical scanner (ATOS compact Scan 5M, GOM GmbH, Braunschweig, Germany). The master and IOS models were aligned using the scan bodies as a reference area. A surface comparison was performed, and deviation labels were exported for each scan body to evaluate the linear and angular deviation. Total body, platform and angular deviations were measured. RESULTS: The use of AGD resulted in a statistically significant increase of angular deviation: 0.87° (SD=0.21) in the AGD group versus 0.64° (SD=0.46) in the no AGD group (p-value=0.005). The difference between the AGD and no AGD groups was not statistically significant for total body and platform deviation values (p-value=0.051 and 0.302 respectively). Using AGD, ITERO showed a statistically significant increase in angular deviation (mean difference=-0.46 µm, p-value=0.002) and a decrease in mean platform deviation (mean difference=63.19 µm, p-value<0.001). No statistically significant differences were found for the other IOS. CONCLUSIONS: The use of AGD did not add benefit on CS and TRIOS. On ITERO, there was an improvement in platform deviation, that was outweighed by the worsening of the angular deviation. CLINICAL SIGNIFICANCE: In vitro data suggest that intraoral scans can be successfully used in full-arch cases. The use of AGD has no additional benefit on CS and TRIOS. On ITERO there was an improvement in platform deviation that was outweighed by the worsening of the angular deviation. Translational application to clinical practice deserves further investigation, taking into account patient-related and anatomical variables.

Chairside virtual patient protocol. Part 3: In vitro accuracy of a digital facebow.

OBJECTIVES: The present study aimed to investigate the trueness and precision of an intraoral transfer element (IOTE) designed for matching intraoral and facial scans. METHODS: A mannequin head with a maxillary model in position was used. Cone beam computed tomography (CBCT) was used to construct the master model (MM). A digital impression of the maxillary arch was taken using an intraoral scanner, and the IOTE was used to record the maxillary arch position. Twenty facial scans with and twenty without the IOTE in place were performed with a handheld device (Ipad Pro, Apple) using a dedicated software. Digital mounting was performed to build a scan model (SM). Using software for data processing, the three-dimensional deviation between the MM and SM at the central left incisor (#9#), and the left and right first molars (#3#, #14#) was calculated as trueness and linear deviation precision. . Angular deviation was also calculated at the occlusal plane. RESULTS: The linear deviation trueness at #9#, #3# and #14# was 0.3 ± 0.12 mm, 1.07 ± 0.28 mm, and 0.18 ± 0.34 mm, respectively, whereas the precision was 1.17 ± 0.4 mm, 0.43 ± 0.12 mm, and 0.64 ± 0.28 mm, respectively. Trueness of the angular deviation at the occlusal plane was 2.17 ± 0.46°, whereas the angular deviation precision was 0.64 ± 0.28°. CONCLUSIONS: Based on in vitro findings the proposed IOTE design is accurate and suitable for clinical use. CLINICAL SIGNIFICANCE: Direct virtual mounting is a reliable technique in vitro; however, in vivo tests are required.

Sinus floor augmentation using crestal approach in conjunction with hydroxyapatite/cross-linked collagen sponge: A pilot study.

BACKGROUND: Different biomaterials were suggested for sinus floor augmentation (SFA). Recently, new materials were launched showing true bone formation without remnants. PURPOSE: The aim of this prospective study was to evaluate an hydroxyapatite-based, sugar cross-linked collagen sponge (OSSIX™ Bone) in transcrestal SFA (t-SFA). MATERIALS AND METHODS: Twenty-four patients with edentulous posterior maxilla and residual bone height (RBH) >4 mm underwent t-SFA with OSSIX™ Bone as grafting material and simultaneous implant placement. The implant Stability Quotient (ISQ) was measured by resonance frequency analysis (RFA) directly after implant insertion and at 6 months. Differences in bone height (BH) and volume were determined in CBCT and x-rays at baseline versus 1 year of follow-up. Graft volume was evaluated by tridimensional reconstructions. Linear regression analysis was used to evaluate the effect of bucco-palatal sinus dimension, RBH, and length of the implant protruding (PIL) into the sinus, on the graft height (GH) changes up to 1 year, and on the graft volume at 1 year. Autocorrelation between time lag and augmented bone volume was evaluated through time series analysis correlograms. Health-related quality-of-life outcomes were captured. RESULTS: Twenty-two patients completed the study. The mean RBH measured at baseline was 5.81 ± 2.2 mm. The mean graft volume was 1085.8 ± 733.4 mm3 . The mean GH, measured in the immediate post-operative period, at 6 and 12 months respectively, was 7.24 mm ±1.94; 6.57 mm ± 2.30; 5.46 mm ± 2.04. The mean ISQ measured after the implant placement was 62.19 ± 8.09, and 6 months later was 76.91 ± 4.50. There was a significant correlation between buccolingual dimension and graft volume at 1 year. Neither buccolingual volume nor RBH had a significant effect on GH change, while the PIL showed a significant positive correlation (P = 0.02 and P = 0.03 at 6 and 12 months, respectively). The correlograms indicated no significant correlation, meaning that there is no tendency for graft volume to increase or decrease over time, therefore suggesting graft stability, at least up to one year of follow-up. 86% of patients had no chewing interference. CONCLUSION: Within the limitations of the study, OSSIX™ Bone could be considered a valid material for SFA due to its manageability and its positive results in promoting new bone formation with long-term stability. T-SFA is confirmed as a less invasive and less painful method.

Chairside virtual patient protocol. Part 2: Management of multiple face scans and alignment predictability.

OBJECTIVES: Face scans are currently used in dentistry to obtain a virtual patient. Find stable and repeatable references for their matching is a fundamental step. Aim of this study is to evaluate matching reliability of multiple face scans using frontal adhesives references. Null hypothesis was that no significant discrepancy could be detected between the references position analyzed both with surface analysis and linear analysis. MATERIALS AND METHODS: Nine patients were enrolled for this study and nine soft tissue adhesives landmarks (APLI Paper S.A.U, 4 mm Ø) placed, equally distributed, on the forehead and glabella. Patients were digitally scanned with a portable scanner (iPad Pro 3rd Gen. Apple Store, Cupertino, CA, USA) using the software Bellus3D (Inc. Campbell, CA, USA) in maximum intercuspation, with a full smile and with a scan reference device. After the scan procedure, a high-definition polygon file format (.ply) was exported, and linear measurements were collected with MeshLab (MeshLab; MeshLab). In order to further evaluate reference accuracy, a surface analysis was performed using a CAD software (GOM inspect, GOM). 3D deviations were calculated as root mean square. Statistical analysis was performed used two repeated-measures ANOVAs. RESULTS: Results showed non-significant differences both for linear measurements (p=.22) and surface analysis (p=.58). Frontal references showed to be clinical reliable landmarks for use during face scans alignment, even with different facial expressions. CONCLUSION: The proposed technique seems to be suitable for the clinical use when superimposition of several face scans is required. CLINICAL SIGNIFICANCE: This study showed the clinical reliability of face scans matching method using adhesives references. These references are cheap and easy to use, allowing for a rapid registration of the patient anatomy.

Chairside virtual patient protocol. Part 1: Free vs Guided face scan protocol.

OBJECTIVES: The 3D facial scan technology allows to virtualize the face of the patient, that can be incorporated with other 3D dental images produced by digital scanning of the dental structures. Aim of this study is to investigate the trueness and precision of a low-cost portable face scanner, with two different scan techniques MATERIALS AND METHODS: Ten patients were enrolled for this study and seventeen soft tissue landmarks were selected to perform linear facial measurements, specifically Reference (Ref), Pronasion (Prn), Subnasal (Sn), Exocanthion Left (Ex-L), Exocanthion Right (Ex-R), Pogonion (Pg), Glabella (G), Alar curvature Right (Al-R), Alar curvature Left (Al-L), Zygion Left (Zn-L), Zygion Right (Zn-R), Orbital Left (Or-L), Orbital Right (Or-R), Tragus Right (T-R), Tragus Left (T-L), Chelion Right (Ch-R) and Chelion Left (Ch-L). Interlandmark distances were measured both manually and digitally. For the manual group ten measurements were made using a digital caliper. For digital group measurements were recorded on the patient face scan obtained using an Ipad Pro 3rd Gen. (Apple Store, Cupertino, CA, USA) and Bellus3D Dental Pro-App (Bellus3D, Inc. Campbell, CA, USA) using "face mode" scan with two different scanning techniques, named Free technique (FT) and Slider Technique (ST). Ten measurements were made for each technique. An open-source software (Meshlab; Meshlab) was used to record all the distances. A paired t-test was used to analyze FT and ST results. In order to further evaluate precision and scan repeatability a surface analysis was performed with both scanning techniques using a CAD software (GOM inspect, GOM) and the total differences in absolute 3D deviations were calculated as root mean square. RESULTS: The comparison between manual and digital measurements showed a mean absolute difference of 0.95±0.25 for FT and 1.00±0.29 for the ST. Trueness analysis showed statistically significant differences for the Exocanthion L- Exocanthion R measurement with FT having better performance (P<.05). Precision analysis showed statistically significant differences for G-Pg, Ref-Zn-R and Prn-Zn-R with ST having better performance (P<.05). To achieve all the scans required without any signs of deformation, 184 scans were performed using Free technique and 124 scans using Slider technique. Surface analysis revealed a mean distance of 0.12±0.45 between Free scans and 0.13±0.46 between Slider scans in accordance with the linear measurement analysis CONCLUSION: The study showed that accuracy of low-cost portable scanner can be suitable for clinical use. The use of ST is suggested for a reliable clinical use due to the better precision and an effective reduction of motion artifacts and the lower compliance required to the patients during the scan.

Microscopic Characterization of Bioactivate Implant Surfaces: Increasing Wettability Using Salts and Dry Technology.

The surface topography of dental implants plays an important role in cell-surface interaction promoting cell adhesion, proliferation and differentiation influencing osseointegration. A hydrophilic implant leads to the absorption of water molecules and subsequently promotes the adhesion of cells to the implant binding protein. Dried salts on the implant surfaces allow one to store the implant surfaces in a dry environment while preserving their hydrophilic characteristics. This process has been identified as "dry technology". The aim of the present study is to describe from a micrometric and nanometric point of view the characteristics of this new bioactivated surface obtained using salts dried on the surface. Topographic analysis, energy-dispersive X-ray spectroscopy, and contact angle characterization were performed on the samples of a sandblasted and dual acid-etched surface (ABT), a nanosurface (Nano) deriving from the former but with the adding of salts air dried and a nanosurface with salts dissolved with distilled water (Nano H2O). The analysis revealed promising results for nanostructured surfaces with increased wettability and a more articulated surface nanotopography than the traditional ABT surface. In conclusion, this study validates a new promising ultra-hydrophilic nano surface obtained by sandblasting, double acid etching and surface salt deposition using dry technology.

The Role of Platelet-Rich Fibrin (PRF) in the Prevention of Medication-Related Osteonecrosis of the Jaw (MRONJ).

Dentoalveolar surgery is probably the major risk factor for MRONJ and for other complications following a tooth extraction, especially in patients affected by systemic diseases. The aim of this retrospective study is to evaluate whether a PRF plug inserted in the post extraction socket can prevent the onset of MRONJ. The patients were divided into two groups according to the surgical protocol that included the insertion or not of the PRF following the extraction and all the anamnestic, and clinical data were analyzed. In the control group, 5 patients developed MRONJ (19.23%) while in the study group, any case of MRONJ was reported. In the control group, patients who developed MRONJ had a CTX with less than 100 pg/mL (5 high-risk patients, Spearman's rank r = .547, p < .001). The use of platelet concentrates in patients with high risk of MRONJ is a user-friendly technique with an excellent cost-benefit ratio in oral surgery.