Palatal asymmetry assessed by intraoral scans: effects of sex, orthodontic treatment, and twinning. A retrospective cohort study.

BACKGROUND: Symmetry is critical in perceived attractiveness, especially in female faces. The palate determines the teeth' alignment and supports facial soft tissues. Therefore, the study aimed to assess the effects of sex, orthodontic treatment, age, and heritability on the directional, anti-, and fluctuational asymmetry in the digital palatal model. METHODS: The palate of 113 twins, 86 female and 27 male subjects, with and without previous orthodontic treatment, were scanned by the Emerald (Planmeca) intraoral scanner. Three lines were constructed horizontally in the digital model, one between the right and left first upper molars and two between the first molars and incisive papilla. Two observers calculated the left and right angles between the mid-sagittal plane and molar-papilla lines. The intraclass correlation coefficient was used to assess the inter-observer absolute agreement. The directional symmetry was determined by comparing the mean left and right angles. The antisymmetry was estimated from the distribution curve of the signed side difference. The fluctuating asymmetry was approximated from the magnitude of the absolute side difference. Finally, the genetic background was assessed by correlating the absolute side difference between monozygotic twin siblings. RESULTS: The right angle (31.1 degrees) was not significantly different from the left one (31.6 degrees). The signed side difference followed a normal distribution with a mean of -0.48 degrees. The absolute side difference (2.29 degrees, p < 0.001) was significantly different from zero and negatively correlated (r=-0.46, p < 0.05) between siblings. None of the asymmetries was affected by sex, orthodontic treatment or age. CONCLUSIONS: The palate illustrates neither directional asymmetry nor antisymmetry, indicating that most people's palates are symmetric. However, the significant fluctuating asymmetry suggests that some subject has considerable asymmetry but is not influenced by sex, orthodontic treatment, age, and genetics. The proposed digital method is a reliable and non-invasive tool that could facilitate achieving a more symmetrical structure during orthodontic and aesthetic rehabilitation. TRIAL REGISTRATION: The Clinicatrial.gov registration number is NCT05349942 (27/04/2022).

Solid index and reverse implant library for the fabrication of a bar for overdenture: a proof of concept.

OBJECTIVES: To present a solid index (SI), a 3D-printed replica of a patient's preexisting complete denture, which allows the dentist to accurately capture the position of the implants and the dental technician to model a bar for overdenture (OD) in CAD software with the use of reverse implant libraries. MATERIALS AND METHODS: A patient in need of rehabilitation of a fully edentulous mandible was restored with an implant OD supported by a polyetheretherketone (PEEK) milled bar. The position of the implants was captured through a physical impression using an SI, with the transfers screwed in. The analogs were then connected, and the SI was scanned upside down to directly capture the position of the implants in the space. This scan was used to design the bar in CAD software using reverse implant libraries, without the need for pouring any SI-derived cast or for using any scanbody. The bar was milled in PEEK. RESULTS: When delivered to the patient, the bar was clinically precise, screwing perfectly onto the implants without any tension or misfit. CONCLUSIONS: The present proof-of-concept article supports the use of an SI and reverse implant libraries for the fabrication of a bar for OD. Further clinical studies are needed to confirm these results.

Digital three-dimensional visualization of intrabony periodontal defects for regenerative surgical treatment planning.

BACKGROUND: In the regenerative treatment of intrabony periodontal defects, surgical strategies are primarily determined by defect morphologies. In certain cases, however, direct clinical measurements and intraoral radiographs do not provide sufficient information on defect morphologies. Therefore, the application of cone-beam computed tomography (CBCT) has been proposed in specific cases. 3D virtual models reconstructed with automatic thresholding algorithms have already been used for diagnostic purposes. The aim of this study was to utilize 3D virtual models, generated with a semi-automatic segmentation method, for the treatment planning of minimally invasive periodontal surgeries and to evaluate the accuracy of the virtual models, by comparing digital measurements to direct intrasurgical measurements. METHODS: Four patients with a total of six intrabony periodontal defects were enrolled in the present study. Two months following initial periodontal treatment, a CBCT scan was taken. The novel semi-automatic segmentation method was performed in an open-source medical image processing software (3D Slicer) to acquire virtual 3D models of alveolar and dental structures. Intrasurgical and digital measurements were taken, and results were compared to validate the accuracy of the digital models. Defect characteristics were determined prior to surgery with conventional diagnostic methods and 3D virtual models. Diagnostic assessments were compared to the actual defect morphology during surgery. RESULTS: Differences between intrasurgical and digital measurements in depth and width of intrabony components of periodontal defects averaged 0.31 ± 0.21 mm and 0.41 ± 0.44 mm, respectively. In five out of six cases, defect characteristics could not be assessed precisely with direct clinical measurements and intraoral radiographs. 3D models generated with the presented semi-automatic segmentation method depicted the defect characteristics correctly in all six cases. CONCLUSION: It can be concluded that 3D virtual models acquired with the described semi-automatic segmentation method provide accurate information on intrabony periodontal defect morphologies, thus influencing the treatment strategy. Within the limitations of this study, models were found to be accurate; however, further investigation with a standardized validation process on a large number of participants has to be conducted.

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

BACKGROUND: The literature has not yet validated the use of intraoral scanners (IOSs) for full-arch (FA) implant impression. Hence, the aim of this in vitro study was to assess and compare the trueness of 12 different IOSs in FA implant impression. METHODS: A stone-cast model of a totally edentulous maxilla with 6 implant analogues and scanbodies (SBs) was scanned with a desktop scanner (Freedom UHD®) to capture a reference model (RM), and with 12 IOSs (ITERO ELEMENTS 5D®; PRIMESCAN® and OMNICAM®; CS 3700® and CS 3600®; TRIOS3®; i-500®; EMERALD S® and EMERALD®; VIRTUO VIVO® and DWIO®; RUNEYES QUICKSCAN®). Ten scans were taken using each IOS, and each was compared to the RM, to evaluate trueness. A mesh/mesh method and a nurbs/nurbs method were used to evaluate the overall trueness of the scans; linear and cross distances between the SBs were used to evaluate the local trueness of the scans. The analysis was performed using reverse engineering software (Studio®, Geomagics; Magics®, Materialise). A statistical evaluation was performed. RESULTS: With the mesh/mesh method, the best results were obtained by CS 3700® (mean error 30.4 µm) followed by ITERO ELEMENTS 5D® (31.4 µm), i-500® (32.2 µm), TRIOS 3® (36.4 µm), CS 3600® (36.5 µm), PRIMESCAN® (38.4 µm), VIRTUO VIVO® (43.8 µm), RUNEYES® (44.4 µm), EMERALD S® (52.9 µm), EMERALD® (76.1 µm), OMNICAM® (79.6 µm) and DWIO® (98.4 µm). With the nurbs/nurbs method, the best results were obtained by ITERO ELEMENTS 5D® (mean error 16.1 µm), followed by PRIMESCAN® (19.3 µm), TRIOS 3® (20.2 µm), i-500® (20.8 µm), CS 3700® (21.9 µm), CS 3600® (24.4 µm), VIRTUO VIVO® (32.0 µm), RUNEYES® (33.9 µm), EMERALD S® (36.8 µm), OMNICAM® (47.0 µm), EMERALD® (51.9 µm) and DWIO® (69.9 µm). Statistically significant differences were found between the IOSs. Linear and cross distances between the SBs (local trueness analysis) confirmed the data that emerged from the overall trueness evaluation. CONCLUSIONS: Different levels of trueness were found among the IOSs evaluated in this study. Further studies are needed to confirm these results.

Solid index impression protocol: a hybrid workflow for high accuracy and passive fit of full-arch implant-supported restorations.

AIM: The purpose of this article is to present the preliminary clinical results obtained with a novel hybrid digital-analog technique, the solid index impression protocol (SIIP), which uses a solid index to capture accurate impressions of multiple implants for the fabrication of implant-supported fixed full arches (FFAs). MATERIALS AND METHODS: This pilot study was based on five patients, each treated with a FFA supported by four implants. Three months after implant placement, impressions were taken for all patients with an intraoral scanner (IOS) (direct digital impression) and with the SIIP, using a custom tray consisting of four hollow cylinders connected with a bar. This index was linked to the implant transfers and transferred to the laboratory, and the definitive FFAs were fabricated based on it. The outcomes of the study were the passive fit of implant superstructures and the accuracy of the models generated by the SIIP, inspected using a coordinate measuring machine (CMM) and reverse engineering software, and compared with the accuracy of direct digital impressions. RESULTS: Excellent clinical precision and passive fit were obtained in all five implant-supported FFAs fabricated with the SIIP. One year after delivery, all FFAs were functional without any complication. Differences in accuracy were found between the SIIP and direct intraoral scanning. CONCLUSIONS: The SIIP seems to represent a viable option for capturing accurate impressions for the fabrication of clinically precise implant-supported FFAs with a hybrid digital-analog workflow. Further studies are needed to confirm these results.

A novel guided surgery system with a sleeveless open frame structure: a retrospective clinical study on 38 partially edentulous patients with 1 year of follow-up.

BACKGROUND: This retrospective clinical study aims to present results of experience with a novel guided surgery system with a sleeveless, open-frame structure, in which the surgical handpiece (not the drills used for preparation) is guided. METHODS: This study was based on an evaluation of the records of partially edentulous patients who had been treated with a sleeveless open-frame guided surgery system (TWIN-Guide®, 2Ingis, Brussels, Belgium), between January 2015 and December 2017. Inclusion criteria were patients with good systemic/oral health and a minimum follow-up of 1 year. Exclusion criteria were patients who had been treated without a guide, or with a guide with sleeves, patients with systemic/oral diseases and who did not have a follow-up of 1 year. The main outcomes were surgical (fit and stability of the surgical guide, duration of the intervention, implant stability, and any intra-operative or immediate post-operative complication), biologic, and prosthetic. RESULTS: Thirty-eight patients (24 males, 14 females; mean age 56.5 ± 14.0 years) were included in the study. These patients had been treated with 110 implants inserted by means of 40 sleeveless, open-frame guides. With regard to fit and stability, 34 guides were excellent, 4 acceptable, and 2 inadequate for use. The mean duration of the intervention was 23.7 (± 6.7) minutes. Immediately after placement, 2 fixtures were not stable and had to be removed. Two patients experienced pain/swelling after surgery. The 108 surviving implants were restored with 36 single crowns and 32 fixed partial prostheses (24 two-unit and 8 three-unit bridges); these restorations survived until the 1-year follow-up, with a low incidence of biologic and prosthetic complications. CONCLUSIONS: Within the limits of this study, this novel guided surgery system with sleeveless, open frame-structure guides seems to be clinically reliable; further studies on a larger sample of patients are needed to confirm these outcomes.

Trueness and precision of 5 intraoral scanners in the impressions of single and multiple implants: a comparative in vitro study.

BACKGROUND: Until now, a few studies have addressed the accuracy of intraoral scanners (IOSs) in implantology. Hence, the aim of this in vitro study was to assess the accuracy of 5 different IOSs in the impressions of single and multiple implants, and to compare them. METHODS: Plaster models were prepared, representative of a partially edentulous maxilla (PEM) to be restored with a single crown (SC) and a partial prosthesis (PP), and a totally edentulous maxilla (TEM) to be restored with a full-arch (FA). These models were scanned with a desktop scanner, to capture reference models (RMs), and with 5 IOSs (CS 3600®, Trios3®, Omnicam®, DWIO®, Emerald®); 10 scans were taken for each model, using each IOS. All IOS datasets were loaded into a reverse-engineering software where they were superimposed on the corresponding RMs, to evaluate trueness, and superimposed on each other within groups, to determine precision. A statistical analysis was performed. RESULTS: In the SC, CS 3600® had the best trueness (15.2 ± 0.8 µm), followed by Trios3® (22.3 ± 0.5 µm), DWIO® (27.8 ± 3.2 µm), Omnicam® (28.4 ± 4.5 µm), Emerald® (43.1 ± 11.5 µm). In the PP, CS 3600® had the best trueness (23 ± 1.1 µm), followed by Trios3® (28.5 ± 0.5 µm), Omnicam® (38.1 ± 8.8 µm), Emerald® (49.3 ± 5.5 µm), DWIO® (49.8 ± 5 µm). In the FA, CS 3600® had the best trueness (44.9 ± 8.9 µm), followed by Trios3® (46.3 ± 4.9 µm), Emerald® (66.3 ± 5.6 µm), Omnicam® (70.4 ± 11.9 µm), DWIO® (92.1 ± 24.1 µm). Significant differences were found between the IOSs; a significant difference in trueness was found between the contexts (SC vs. PP vs. FA). In the SC, CS 3600® had the best precision (11.3 ± 1.1 µm), followed by Trios3® (15.2 ± 0.8 µm), DWIO® (27.1 ± 10.7 µm), Omnicam® (30.6 ± 3.3 µm), Emerald® (32.8 ± 10.7 µm). In the PP, CS 3600® had the best precision (17 ± 2.3 µm), followed by Trios3® (21 ± 1.9 µm), Emerald® (29.9 ± 8.9 µm), DWIO® (34.8 ± 10.8 µm), Omnicam® (43.2 ± 9.4 µm). In the FA, Trios3® had the best precision (35.6 ± 3.4 µm), followed by CS 3600® (35.7 ± 4.3 µm), Emerald® (61.5 ± 18.1 µm), Omnicam® (89.3 ± 14 µm), DWIO® (111 ± 24.8 µm). Significant differences were found between the IOSs; a significant difference in precision was found between the contexts (SC vs. PP vs. FA). CONCLUSIONS: The IOSs showed significant differences between them, both in trueness and in precision. The mathematical error increased in the transition from SC to PP up to FA, both in trueness than in precision.

Combining Intraoral Scans, Cone Beam Computed Tomography and Face Scans: The Virtual Patient.

PURPOSE: The aim of this literature review was to provide an update on the current scientific knowledge in the field of 3D virtual patient science and to identify a possible easy, smart, and affordable method to combine different file formats obtained from different digital devices. METHODS: Electronic searches of the Medline database was performed, up to May 2017, for articles dealing with the construction of a 3D virtual patient; the matching of data acquired with different digital devices (cone beam computed tomography, CBCT; face scanner, FS; intraoral scanner, IOS; and desktop scanner, DS) was considered. The inclusion of studies was based on the superimposition of at least 2 different digital sources. RESULTS: Twenty-five studies were selected for subsequent examination. Only 3 studies analyzed the feasibility of superimposition of 3 different types of 3D data (CBCT + FS + IOS/DS). The most frequently used matching procedure was between CBCT and FS and CBCT and IOS/DS. CONCLUSION: The procedure of superimposition of data from CBCT, IOS, and FS is currently feasible and it is now possible to create a 3D "virtual patient" to better diagnose, plan the treatment, and communicate with patients.

The Modified Socket Shield Technique.

OBJECTIVE: In the anterior regions, the resorption of the buccal bone after tooth extraction leads to a contraction of the overlying soft tissues, resulting in an esthetic problem, particularly with immediate implant placement. In the socket shield technique, the buccal root section of the tooth is maintained, to preserve the buccal bone for immediate implant placement. The aim of this prospective study was to investigate the survival, stability, and complication rates of implants placed using a "modified" socket shield technique. METHODS: Over a 2-year period, all patients referred to a dental clinic for treatment with oral implants were considered for inclusion in this study. Inclusion criteria were healthy adult patients who presented nonrestorable single teeth with intact buccal periodontal tissues in the anterior regions of both jaws. Exclusion criteria were teeth with present/past periodontal disease, vertical root fractures on the buccal aspect, horizontal fractures below bone level, and external/internal resorptions. The buccal portion of the root was retained to prevent the resorption of the buccal bone; the shield was 1.5 mm thick with the most coronal portion at the bone crest level. All patients then underwent immediate implants. In the patient with a gap between the implant and shield, no graft material was placed. All implants were immediately restored with single crowns and followed for 1 year. The main outcomes were implant survival, stability, and complications. RESULTS: Thirty patients (15 males, 15 females; mean age was 48.2 ±â€Š15.0 years) were enrolled in the study and installed with 40 immediate implants. After 1 year, all implants were functioning, for a survival rate of 100%; excellent implant stability was reported (mean implant stability quotient at placement: 72.9 ±â€Š5.9; after 1 year: 74.6 ±â€Š2.7). No biologic complications were reported, and the incidence of prosthetic complications was low (2.5%). CONCLUSIONS: The "modified" socket shield technique seems to be a successful procedure when combined with immediate implant placement, because the root fragment does not interfere with osseointegration and may be beneficial for the esthetics, protecting the buccal bone from resorption.

A novel in vivo method to evaluate trueness of digital impressions.

BACKGROUND: Intraoral scanners are devices for capturing digital impressions in dentistry. Until now, several in vitro studies have assessed the trueness of digital impressions, but in vivo studies are missing. Therefore, the purpose of this study was to introduce a new method to assess trueness of intraoral scanners and digital impressions in an in vivo clinical set-up. METHODS: A digital impression using an intraoral scanner (Trios® 3 Cart wired, 3Shape, Copenhagen, Denmark) and a conventional alginate impression (Cavex Impressional®, Cavex, Haarlem, the Netherlands) as clinical reference were made for two patients assigned for full mouth extraction. A total of 30 teeth were collected upon surgery after impressions making. The gypsum model created from conventional impression and extracted teeth were then scanned in a lab scanner (Activity 885®, SmartOptics, Bochum, Germany). Digital model of the intraoral scanner (DM), digital model of the conventional gypsum cast (CM) and those of the extracted natural teeth (NT) were imported to a reverse engineering software (3-matic®, Materialise, Leuven, Belgium) in which the three models were registered then DM and CM were compared to their corresponding teeth in NT by distance map calculations. RESULTS: DM had statistically insignificant better trueness when compared to CM for total dataset (p = 0.15), statistically insignificant better trueness for CM when mandibular arches analyzed alone (p = 0.56), while a significantly better DM trueness (p = 0.013) was found when only maxillary arches were compared. CONCLUSIONS: Our results show that digital impression technique is clinically as good as or better than the current reference standard for study models of orthognathic surgery patients.

Aesthetic outcome of immediately restored single implants placed in extraction sockets and healed sites of the anterior maxilla: a retrospective study on 103 patients with 3 years of follow-up.

OBJECTIVES: The aim of this study was to compare the aesthetic outcome of single implants in extraction sockets and healed ridges of the anterior maxilla by means of the pink aesthetic score/white aesthetic score (PES/WES) index. MATERIALS AND METHODS: This retrospective study was based on data from 103 patients (43 males, 60 females) aged 24-65 years (mean age 41.4 ± 13.8 years) who had been successfully treated with a single implant in the anterior maxilla, in four different clinical centres. Forty-two patients (mean age 46.5 ± 15.1 years) were treated with a single implant in a fresh post-extraction socket (immediate implant treatment, IIT), while 61 patients (mean age 38.0 ± 11.8 years) were treated with a single implant in a healed site (conventional implant treatment, CIT). Two independent calibrated examiners applied the PES/WES index to the 103 single-tooth restorations, respectively 3 months and 3 years after implant placement. RESULTS: A few biological (4.8%) and prosthetic (8.7%) complications were reported. Both IIT and CIT yielded satisfactory aesthetic outcomes. At the delivery of the final restoration, a PES/WES score of 16.6 ± 2.6 and 15.7 ± 3.0 was reported for IIT and CIT, respectively: this difference was not statistically significant. A higher decrease in the PES/WES score was observed with CIT over time. At 3 years, a PES/WES score of 16.4 ± 2.8 and 15.2 ± 3.3 was reported for IIT and CIT, respectively: this difference was statistically significant. IIT seemed to yield better aesthetic outcomes in young patients (≤30 years), with implants placed in central incisor/cuspid areas, in the presence of bone contouring. CONCLUSIONS: Both immediate and conventional single-implant treatment in the anterior maxilla can yield satisfactory aesthetic outcomes, when performed by experienced clinicians in well-selected cases. Further studies are needed to confirm these results.

Early bone formation around immediately loaded implants with nanostructured calcium-incorporated and machined surface: a randomized, controlled histologic and histomorphometric study in the human posterior maxilla.

OBJECTIVE: The aim of this randomized, controlled histologic/histomorphometric study was to compare the early bone formation around immediately loaded implants with nanostructured calcium-incorporated (NCI) and machined (MA) surface, placed in the human posterior maxilla. MATERIALS AND METHODS: Fifteen fully edentulous patients (six males; nine females; mean age 57.9 ± 6.7 years) were selected for this study. Each patient was installed with two temporary transmucosal implants, with different surfaces: one NCI (test) and one MA (control) implant. All temporary implants were placed in the posterior maxilla, according to a split-mouth design, to help to support an interim complete maxillary denture. After 8 weeks, all temporary transmucosal implants were retrieved for histologic/histomorphometric evaluation. The bone-to-implant contact (BIC%) and the bone density (BD%) were calculated. The Wilcoxon matched-pairs signed-rank test was used to evaluate differences (BIC%, BD%) between the surfaces. The level of significance was set at 0.05. RESULTS: Eight weeks after placement, 24 clinically stable implants (12 test, 12 control) were subjected to histologic/histomorphometric evaluation. In the MA implants, the histomorphometric evaluation revealed a mean BIC(±SD)% and BD(±SD)% of 21.2(±4.9)% and 29.8(±7.8)%, respectively. In the NCI implants, the histomorphometric analysis revealed a mean BIC(±SD)% and BD(±SD)% of 39.7(±8.7)% and 34.6(±7.2)%, respectively. A statistically significant difference was found between the two surfaces with regard to BIC% (p < 0.001), while no significant difference was found with regard to BD% (p = 0.09). CONCLUSIONS: The NCI surface seems to increase the peri-implant endosseous healing properties in the native bone of the posterior maxilla, under immediate loading conditions, when compared with the MA surface. CLINICAL RELEVANCE: Under immediate loading conditions in the human posterior maxilla, the nanostructured calcium-incorporated surface has led to better histologic and histomorphometric results than the machined surface; therefore, the clinical use of implants with nanostructured calcium-incorporated surface may be beneficial in the posterior maxilla, under immediate loading protocol.

Early Bone Response to Dual Acid-Etched and Machined Dental Implants Placed in the Posterior Maxilla: A Histologic and Histomorphometric Human Study.

PURPOSE: To compare the early bone response to implants with dual acid-etched (DAE) and machined (MA) surface, when placed in the posterior human maxilla. MATERIALS AND METHODS: Fourteen patients received 2 implants in the posterior maxilla: 1 DAE and 1 MA. After 2 months, the implants were retrieved for histologic/histomorphometric evaluation. The bone-to-implant contact (BIC%), bone density in the threaded area (BDTA%), and the bone density (BD%) were calculated. The Wilcoxon matched-pairs signed rank test was used to evaluate differences (BIC%, BDTA%, and BD%) between the surfaces. RESULTS: In the MA implants, a mean (±SD) BIC%, BDTA%, and BD% of 21.76 (±12.79), 28.58 (±16.91), and 21.54 (±11.67), respectively, was reported. In the DAE implants, a mean (±SD) BIC%, BDTA%, and BD% of 37.49 (±29.51), 30.59 (±21.78), and 31.60 (±18.06), respectively, was reported. Although the mean BIC% of DAE implants value was almost double than that of MA implants, no significant differences were found between the 2 groups with regard to BIC% (P = 0.198) and with regard to BDTA% (P = 0.778) and BD% (P = 0.124). CONCLUSIONS: The DAE surface increased the periimplant endosseous healing properties in the native bone of the posterior maxilla.

Horizontal ridge reconstruction of the anterior maxilla using customized allogeneic bone blocks with a minimally invasive technique - a case series.

BACKGROUND: Different surgical procedures have been proposed to achieve horizontal ridge reconstruction of the anterior maxilla; all these procedures, however, require bone replacement materials to be adapted to the bone defect at the time of implantation, resulting in complex and time-consuming procedures. The purpose of this study was to describe how to use a 3D printed hardcopy model of the maxilla to prepare customized milled bone blocks, to be adapted on the bone defect areas using a minimally invasive subperiosteal tunneling technique. METHODS: Cone beam computed tomography (CBCT) images of the atrophic maxilla of six patients were acquired and modified into 3D reconstruction models. Data were transferred to a 3D printer and solid models were fabricated using autoclavable nylon polyamide. Before the surgery, freeze-dried cortico-cancellous blocks were manually milled and adapted on the 3D printed hardcopy models of the maxillary bone, in order to obtain customized allogeneic bone blocks. RESULTS: In total, eleven onlay customized allogeneic bone grafts were prepared and implanted in 6 patients, using a minimally invasive subperiosteal tunneling technique. The scaffolds closely matched the shape of the defects: this reduced the operation time and contributed to good healing. The patients did not demonstrate adverse events such as inflammation, dehiscence or flap re-opening during the recovery period; however, one patient experienced scaffold resorption, which was likely caused by uncontrolled motion of the removable provisional prosthesis. Following a 6 month healing period, CBCT was used to assess graft integration, which was followed by insertion of implants into the augmented areas. Prosthetic restorations were placed 4 months later. CONCLUSIONS: These observations suggest that customized bone allografts can be successfully used for horizontal ridge reconstruction of the anterior maxilla: patients demonstrated reduced morbidity and decreased total surgery time. Further studies on a larger sample of patients, with histologic evaluation and longer follow-up are needed to confirm the present observations.

Accuracy of four intraoral scanners in oral implantology: a comparative in vitro study.

BACKGROUND: Until now, only a few studies have compared the ability of different intraoral scanners (IOS) to capture high-quality impressions in patients with dental implants. Hence, the aim of this study was to compare the trueness and precision of four IOS in a partially edentulous model (PEM) with three implants and in a fully edentulous model (FEM) with six implants. METHODS: Two gypsum models were prepared with respectively three and six implant analogues, and polyether-ether-ketone cylinders screwed on. These models were scanned with a reference scanner (ScanRider®), and with four IOS (CS3600®, Trios3®, Omnicam®, TrueDefinition®); five scans were taken for each model, using each IOS. All IOS datasets were loaded into reverse-engineering software, where they were superimposed on the reference model, to evaluate trueness, and superimposed on each other within groups, to determine precision. A detailed statistical analysis was carried out. RESULTS: In the PEM, CS3600® had the best trueness (45.8 ± 1.6µm), followed by Trios3® (50.2 ± 2.5µm), Omnicam® (58.8 ± 1.6µm) and TrueDefinition® (61.4 ± 3.0µm). Significant differences were found between CS3600® and Trios3®, CS3600® and Omnicam®, CS3600® and TrueDefinition®, Trios3® and Omnicam®, Trios3® and TrueDefinition®. In the FEM, CS3600® had the best trueness (60.6 ± 11.7µm), followed by Omnicam® (66.4 ± 3.9µm), Trios3® (67.2 ± 6.9µm) and TrueDefinition® (106.4 ± 23.1µm). Significant differences were found between CS3600® and TrueDefinition®, Trios3® and TrueDefinition®, Omnicam® and TrueDefinition®. For all scanners, the trueness values obtained in the PEM were significantly better than those obtained in the FEM. In the PEM, TrueDefinition® had the best precision (19.5 ± 3.1µm), followed by Trios3® (24.5 ± 3.7µm), CS3600® (24.8 ± 4.6µm) and Omnicam® (26.3 ± 1.5µm); no statistically significant differences were found among different IOS. In the FEM, Trios3® had the best precision (31.5 ± 9.8µm), followed by Omnicam® (57.2 ± 9.1µm), CS3600® (65.5 ± 16.7µm) and TrueDefinition® (75.3 ± 43.8µm); no statistically significant differences were found among different IOS. For CS3600®, For CS3600®, Omnicam® and TrueDefinition®, the values obtained in the PEM were significantly better than those obtained in the FEM; no significant differences were found for Trios3®. CONCLUSIONS: Significant differences in trueness were found among different IOS; for each scanner, the trueness was higher in the PEM than in the FEM. Conversely, the IOS did not significantly differ in precision; for CS3600®, Omnicam® and TrueDefinition®, the precision was higher in the PEM than in the FEM. These findings may have important clinical implications.

Short (8-mm) locking-taper implants supporting single crowns in posterior region: a prospective clinical study with 1-to 10-years of follow-up.

OBJECTIVE: The aim of this study was to evaluate the long-term outcome of short (8-mm) locking-taper implants supporting single crowns in the posterior regions and to analyze the influence of different factors on implant survival and implant-crown success rates. MATERIALS AND METHODS: Between June 2002 and September 2011, all patients referred to two private practices for treatment with short (8-mm) implants supporting single tooth restorations in posterior areas of both jaws were considered for inclusion in this study. At each annual follow-up session, clinical and radiographic parameters were assessed. Implant-crown success criteria included absence of pain, suppuration, mobility, and peri-implant radiolucency, distance between the implant shoulder and the first visible bone-to-implant contact (DIB) <1.5 mm after 12 months and not exceeding 0.2 mm for each following year, absence of prosthetic complications. The cumulative survival and implant-crown success were assessed using the Kaplan-Meier survival estimator; Chi-square test was applied to evaluate correlations between the study variables. The statistical analysis was performed at the patient and at the implant level. RESULTS: Two hundred and fifteen implants (124 maxilla; 91 mandible) were placed in 194 patients (104 men; 90 women). Three implants failed (2 maxilla; 1 mandible). The 10-year cumulative survival rate was 98.4% (patient-based) and 98.5% (implant-based). Among the surviving implants, the mean DIB was 0.31 (±0.24), 0.43 (±0.29), and 0.62 (±0.31) mm at the 1-, 5-, and 10-year follow-up session; two biologic and three prosthetic complications were reported, for a 10-year cumulative implant-crown success rate of 95.8% (patient-based) and 95.9% (implant-based). The implant survival and implant-crown success rates did not differ significantly with respect to patients' gender, age, smoking habit, parafunctional habit, implant location, implant diameter, and bone type. CONCLUSIONS: The use of short (8-mm) locking-taper implants is a predictable treatment modality for the restoration of single tooth gaps of posterior segments of dentition.

Immediate, non-submerged, root-analogue direct laser metal sintering (DLMS) implants: a 1-year prospective study on 15 patients.

This study evaluated the 1-year survival and success rate of root-analogue direct laser metal sintering (DLMS) implants, placed into the extraction sockets of 15 patients. DLMS is a technology which allows solids with complex geometry to be fabricated by annealing metal powder microparticles in a focused laser beam, according to a computer-generated three-dimensional (3D) model; the fabrication process involves the laser-induced fusion of titanium microparticles, in order to build, layer-by-layer, the desired object. Cone-beam computed tomography (CBCT) acquisition and 3D image conversion, combined with the DLMS process, allow the fabrication of custom-made, root-analogue implants (RAIs). CBCT images of 15 non-restorable premolars (eight maxilla; seven mandible) were acquired and transformed into 3D models: from these, custom-made, root-analogue DLMS implants with integral abutment were fabricated. Immediately after tooth extraction, the RAIs were placed in the sockets and restored with a single crown. One year after implant placement, clinical and radiographic parameters were assessed: success criteria included absence of pain, suppuration, and exudation; absence of implant mobility and absence of continuous peri-implant radiolucency; distance between the implant shoulder and the first visible bone-to-implant contact <1.5 mm from initial surgery; and absence of prosthetic complications. At the 1-year follow-up, no implants were lost, for a survival rate of 100 %. All implants were stable, with no signs of infection. The good conditions of the peri-implant tissues were confirmed by the radiographic examination, with a mean DIB of 0.7 mm (±0.2). The possibility of fabricating custom-made, RAI DLMS implants opens new interesting horizons for immediate placement of dental implants.

Artificial intelligence and mixed reality for dental implant planning: A technical note.

AIM: The aim of this work is to present a new protocol for implant surgical planning which involves the combined use of artificial intelligence (AI) and mixed reality (MR). METHODS: This protocol involves the acquisition of three-dimensional (3D) patient data through intraoral scanning (IOS) and cone beam computed tomography (CBCT). These data are loaded into AI software which automatically segments and aligns the patient's 3D models. These 3D models are loaded into MR software and used for planning implant surgery through holography. The files are then exported and used to design surgical guides via open-source software, which are 3D printed and used to prepare the implant sites through static computer-assisted implant surgery (s-CAIS). The case is finalized prosthetically through a fully digital protocol. The accuracy of implant positioning is verified by comparing the planned position with the actual position of the implants after surgery. RESULTS: As a proof of principle, the present protocol seems to be to be reliable and efficient when used for planning simple cases of s-CAIS in partially edentulous patients. The clinician can plan the implants in an authentic 3D environment without using any radiology-guided surgery software. The precision of implant placement seems clinically acceptable, with minor deviations. CONCLUSIONS: The present study suggests that AI and MR technologies can be successfully used in s-CAIS for an authentic 3D planning. Further clinical studies are needed to validate this protocol.

Trueness, precision, time-efficiency and cost analysis of chairside additive and subtractive versus lab-based workflows for manufacturing single crowns: An in vitro study.

PURPOSE: To evaluate the trueness, precision, time efficiency, and cost of three different workflows for manufacturing single crowns (SCs). METHODS: A plaster model with a prepared tooth (#15) was scanned with an industrial scanner, and an SC was designed in computer-assisted-design (CAD) software. Ten SCs were printed with a hybrid composite (additive chairside) and a stereolithographic (SLA) printer (Dfab®), 10 SCs were milled in lithium disilicate (subtractive chairside) using a chairside milling unit (inLab MC XL®), and 10 SCs were milled in zirconia (lab-based) using a five-axis laboratory machine (DWX-52D®). All SCs were scanned with the same scanner after polymerization/sinterization. Each scan was superimposed to the marginal area of the original CAD file to evaluate trueness: absolute average (ABS AVG), root mean square (RMS), and (90˚-10˚)/2 percentile were calculated for each group. Marginal adaptation and quality of the occlusal and interproximal contact points were also investigated by two prosthodontists on 3D printed and plaster models. Finally, the three workflows' time efficiency and costs were evaluated. RESULTS: Additive chairside and subtractive lab-based SCs had significantly better marginal trueness than subtractive chairside SCs in all three parameters (ABS AVG, p < 0.01; RMS, p < 0.01; [90˚-10˚]/2, p < 0.01). However, the two prosthodontists found no significant differences between the three manufacturing procedures in the quality of the marginal closure (p = 0.186), interproximal (p = 0.319), and occlusal contacts (p = 0.218). Both time efficiency and cost show a trend favoring the chairside additive workflow. CONCLUSIONS: Chairside additive technology seems to represent a valid alternative for manufacturing definitive SCs, given the high marginal trueness, precision, workflow efficiency and low costs. STATEMENT OF CLINICAL RELEVANCE: Additive chairside manufacturing of definitive hybrid composite SCs is now possible and shows high accuracy, time efficiency, and competitive cost.