Synthesis of 64Cu-, 55Co-, and 68Ga-Labeled Radiopharmaceuticals Targeting Neurotensin Receptor-1 for Theranostics: Adjusting In Vivo Distribution Using Multiamine Macrocycles.

The development of theranostic radiotracers relies on their binding to specific molecular markers of a particular disease and the use of corresponding radiopharmaceutical pairs thereafter. This study reports the use of multiamine macrocyclic moieties (MAs), as linkers or chelators, in tracers targeting the neurotensin receptor-1 (NTSR-1). The goal is to achieve elevated tumor uptake, minimal background interference, and prolonged tumor retention in NTSR-1-positive tumors. Methods: We synthesized a series of neurotensin antagonists bearing MA linkers and metal chelators. The MA unit is hypothesized to establish a strong interaction with the cell membrane, and the addition of a second chelator may enhance water solubility, consequently reducing liver uptake. Small-animal PET/CT imaging of [64Cu]Cu-DOTA-SR-3MA, [64Cu]Cu-NT-CB-NOTA, [68Ga]Ga-NT-CB-NOTA, [64Cu]Cu-NT-CB-DOTA, and [64Cu]Cu-NT-Sarcage was acquired at 1, 4, 24, and 48 h after injection using H1299 tumor models. [55Co]Co-NT-CB-NOTA was also tested in HT29 (high NTSR-1 expression) and Caco2 (low NTSR-1 expression) colorectal adenocarcinoma tumor models. Saturation binding assay and internalization of [55Co]Co-NT-CB-NOTA were used to test tracer specificity and internalization in HT29 cells. Results: In vivo PET imaging with [64Cu]Cu-NT-CB-NOTA, [68Ga]Ga-NT-CB-NOTA, and [55Co]Co-NT-CB-NOTA revealed high tumor uptake, high tumor-to-background contrast, and sustained tumor retention (≤48 h after injection) in NTSR-1-positive tumors. Tumor uptake of [64Cu]Cu-NT-CB-NOTA remained at 76.9% at 48 h after injection compared with uptake 1 h after injection in H1299 tumor models, and [55Co]Co-NT-CB-NOTA was retained at 60.2% at 24 h compared with uptake 1 h after injection in HT29 tumor models. [64Cu]Cu-NT-Sarcage also showed high tumor uptake with low background and high tumor retention 48 h after injection Conclusion: Tumor uptake and pharmacokinetic properties of NTSR-1-targeting radiopharmaceuticals were greatly improved when attached with different nitrogen-containing macrocyclic moieties. The study results suggest that NT-CB-NOTA labeled with either 64Cu/67Cu, 55Co/58mCo, or 68Ga (effect of 177Lu in tumor to be determined in future studies) and NT-Sarcage labeled with 64Cu/67Cu or 55Co/58mCo may be excellent diagnostic and therapeutic radiopharmaceuticals targeting NTSR-1-positive cancers. Also, the introduction of MA units to other ligands is warranted in future studies to test the generality of this approach.

Influence of scanning protocol on the accuracy of complete-arch digital implant scans: An in vitro study.

OBJECTIVE: This in-vitro study assessed the influence of two intraoral scanning (IOS) protocols on the accuracy (trueness and precision) of digital scans performed in edentulous arches. METHODS: Twenty-two abutment-level master casts of edentulous arches with at least four implants were scanned repeatedly five times, each with two different scanning protocols. Protocol A (IOS-A) consisted of scanning the edentulous arch before inserting the implant scan bodies, followed by their insertion and its subsequent digital acquisition. Protocol B (IOS-B) consisted of scanning the edentulous arch with the scan bodies inserted from the outset. A reference scan from each edentulous cast was obtained using a laboratory scanner. Trueness and precision were calculated using the spatial fit analysis, cross-arch distance, and virtual Sheffield test. Statistical analysis was performed using generalized estimating equations (GEEs). Statistical significance was set at α = .05. RESULTS: In the spatial fit test, the precision of average 3D distances was 45 µm (±23 µm) with protocol IOS-A and 25 µm (±10 µm) for IOS-B (p < .001), and the trueness of average 3D distances was 44 µm (±24 µm) with protocol IOS-A and 24 µm (±7 µm) for IOS-B (p < .001). Cross-arch distance precision was 59 µm (±53 µm) for IOS-A and 41 µm (±43 µm) for IOS-B (p = .0035), and trueness was 64 µm (±47 µm) for IOS-A and 50 µm (±40 µm) for IOS-B (p = .0021). Virtual Sheffield precision was 286 µm (±198 µm) for IOS-A and 146 µm (±92 µm) for IOS-B (p < .001), and trueness was 228 µm (±171 µm) for IOS-A and 139 µm (±92 µm) for IOS-B (p < .001). CONCLUSIONS: The IOS-B protocol demonstrated significantly superior accuracy. Placement of scan bodies before scanning the edentulous arch is recommended to improve the accuracy of complete-arch intraoral scanning.

Echo-intensity characterization at implant sites and novel diagnostic ultrasonographic markers for peri-implantitis.

AIM: To apply high-frequency ultrasound (HFUS) echo intensity for characterizing peri-implant tissues at healthy and diseased sites and to investigate the possible ultrasonographic markers of health versus disease. MATERIALS AND METHODS: Sixty patients presenting 60 implants diagnosed as healthy (N = 30) and peri-implantitis (N = 30) were assessed with HFUS. HFUS scans were imported into a software where first-order greyscale outcomes [i.e., mean echo intensity (EI)] and second-order greyscale outcomes were assessed. Other ultrasonographic outcomes of interest involved the vertical extension of the hypoechoic supracrestal area (HSA), soft-tissue area (STA) and buccal bone dehiscence (BBD), among others. RESULTS: HFUS EI mean values obtained from peri-implant soft tissue at healthy and diseased sites were 122.9 ± 19.7 and 107.9 ± 24.7 grey levels (GL); p = .02, respectively. All the diseased sites showed the appearance of an HSA that was not present in healthy implants (area under the curve = 1). The proportion of HSA/STA was 37.9% ± 14.8%. Regression analysis showed that EI of the peri-implant soft tissue was significantly different between healthy and peri-implantitis sites (odds ratio 0.97 [95% confidence interval: 0.94-0.99], p = .019). CONCLUSIONS: HFUS EI characterization of peri-implant tissues shows a significant difference between healthy and diseased sites. HFUS EI and the presence/absence of an HSA may be valid diagnostic ultrasonographic markers to discriminate peri-implant health status.

Impact of digital technologies on implant surgery in fully edentulous patients: A scoping review.

BACKGROUND: For over three decades, digital technologies have been used in Implant Dentistry, beginning with the introduction of planning software for Static Computer-Assisted Implant Surgery (S-CAIS). During this time, this field has witnessed the emergence of diverse methodologies and a proliferation of technological advancements. Today, S-CAIS is a widely adopted procedure for the placement of dental implants in both partially and fully edentulous patients, with Dynamic Computer-Assisted Surgery (D-CAIS) and Robotic-Assisted Implant Surgery (RAIS) rapidly gaining attention among dental professionals. The continuous advancements in this arena are not merely indicative of technological progress; they represent a steadfast dedication to refining precision, enhancing efficiency, and fostering innovation with the goal of optimizing patient outcomes in dental implantology. AIMS: The purpose of the following review is to meticulously examine the spectrum of digital technologies available and to describe their protocols, advantages, and shortcomings as well as to evaluate their accuracy in implant surgery in patients with complete edentulism. MATERIALS AND METHODS: A scoping review was performed following the Joanna Briggs Institute (JBI) protocols, leveraging the population, concept, and context (PCC) framework to construct the research question and determine the inclusion and exclusion criteria. RESULTS: Two hundred and sixty-seven records were identified for screening. After applying all the screening criteria, 41 articles were included for review and qualitative data analysis. DISCUSSION: S-CAIS, D-CAIS, and RAIS were identified as the main technologies for computer assisted implant surgery. Their applications, characteristics, protocols and levels of accuracy were compared and described. CONCLUSION: Taking into consideration the limitations of this study, S-CAIS appears to be the most applied and validated technology in implant surgery for fully edentulous patients followed by D-CAIS and RAIS being these last two promising initiatives in the field. Despite having similar levels of accuracy, the overall comparison showed a slightly higher values in RAIS followed by D-CAIS and S-CAIS.

The Use of CAD-CAM Templates in Lateral Sinus Floor Augmentation Procedure: A Systematic Review.

INTRODUCTION: Maxillary sinus floor augmentation is a procedure known for its long-term success and predictable outcomes. However, the perforation of the Schneiderian membrane remains the most common complication associated with this procedure. OBJECTIVE: This systematic review aims to determine the presence of complications during maxillary sinus floor augmentation procedures using CAD-CAM surgical templates. MATERIAL AND METHODS: An electronic search was carried out in MEDLINE (via PubMed), Web of Science, and Scopus. A descriptive analysis of the data was performed. Studies that have performed lateral sinus floor augmentation were included in the inclusion criteria. The CAD-CAM surgical template design and the intraoperative complications were registered. RESULTS: A total of 13 studies were included. Seven were case reports, four were case series, and two were randomized clinical trials. A total of 94 lateral SFA procedures were included (84 using CADCAM templates and 10 without using templates). Three of the 84 maxillary sinus floor augmentation procedures using a CAD-CAM template presented intraoperative complications. CONCLUSIONS: Maxillary sinus floor augmentation performed by using CAD-CAM surgical templates could be related to low rates of complications, however, due to the heterogeneity of the articles included, more standardized studies are needed to confirm these outcomes.

The Anatomy of the Mandibular Incisive Canal and Its Influence in Implant Therapy. A Scoping Review.

INTRODUCTION: The interforaminal region is considered more favorable for implant placement than the posterior mandible in edentulous patients, mainly because of the interference of the inferior alveolar nerve with implant placement in the severely resorbed posterior mandible. However, complications in the interforaminal region may occur due to the presence of the mandibular incisive nerve. OBJECTIVE: This scoping review aims to describe the mandibular incisive nerve anatomy related to the potential interference in implant therapy. MATERIAL AND METHODS: A comprehensive literature search was conducted in the following databases: MEDLINE (via PubMed), Web of Science, and Scopus. This scoping review was structured according to the Joanna Briggs Institute method. RESULTS: Thirteen studies were included in the review. All the studies were observational cohort anatomical studies, carried out mainly by CBCT and on cadavers. A total of 1471 patients/cadavers were studied. The mandibular incisive nerve was presented in 87-100% of the cases, with an average length of 9.97 mm and an average diameter of 1.97 mm. The mandibular incisive nerve may be damaged during drilling and implant placement, especially using implant lengths larger than 12 mm. CONCLUSIONS: Damage to the mandibular incisive nerve due to implant placement could be present, however, it is necessary to conduct more studies focusing on assessing mandibular incisive nerve damage to understand the clinical relevance of this nerve and its associated morbidities such as neurosensorial alterations. Due to the different anatomical characteristics of this nerve, CBCT analysis is recommended for implant therapy in the anterior mandible to prevent the described complications.

Considerations for predictable outcomes in static computer- aided implant surgery in the esthetic zone.

OBJECTIVE: To provide technical and clinical recommendations for implementing a digital workflow in Static Computer-Aided Implant Surgery in the anterior maxilla. CLINICAL CONSIDERATIONS: An optimal 3D implant position is crucial for achieving satisfying results in implant rehabilitation in the esthetic area. Due to its complexity, implant placement in the esthetic zone should be executed with precision and predictability. Static Computer-Aided Implant Surgery requires thorough planning and detailed attention to every step of the digital workflow protocol. CONCLUSIONS: Implant positioning in the esthetic zone using Static Computer-Aided Implant Surgery is a technique-sensitive procedure that requires precise execution of each step. This approach ensures accurate prosthetically driven 3D implant placement and prevents potential errors that could lead to inaccurate positioning. CLINICAL SIGNIFICANCE: The proper implementation of Static Computer-Aided Implant Surgery may increase the level of agreement between the planned and definitive implant 3D positions in the esthetic zone, thus enhancing the esthetic outcomes of implant rehabilitation.

Potential of olfactory neuroepithelial cells as a model to study schizophrenia: A focus on GPCRs (Review).

Schizophrenia (SZ) is a multifactorial disorder characterized by volume reduction in gray and white matter, oxidative stress, neuroinflammation, altered neurotransmission, as well as molecular deficiencies such as punctual mutation in Disrupted­in­Schizophrenia 1 protein. In this regard, it is essential to understand the underlying molecular disturbances to determine the pathophysiological mechanisms of the disease. The signaling pathways activated by G protein­coupled receptors (GPCRs) are key molecular signaling pathways altered in SZ. Convenient models need to be designed and validated to study these processes and mechanisms at the cellular level. Cultured olfactory stem cells are used to investigate neural molecular and cellular alterations related to the pathophysiology of SZ. Multipotent human olfactory stem cells are undifferentiated and express GPCRs involved in numerous physiological functions such as proliferation, differentiation and bioenergetics. The use of olfactory stem cells obtained from patients with SZ may identify alterations in GPCR signaling that underlie dysfunctional processes in both undifferentiated and specialized neurons or derived neuroglia. The present review aimed to analyze the role of GPCRs and their signaling in the pathophysiology of SZ. Culture of olfactory epithelial cells constitutes a suitable model to study SZ and other psychiatric disorders at the cellular level.

Milled PMMA, a Material for Long-Term Implant Supported Fixed Complete Dental Prostheses.

Traditionally, metal-ceramics, metal-reinforced acrylics, and more recently full-contour or layered zirconia have been the materials of choice for definitive fixed implant-supported rehabilitations. Polymethyl Methacrylate (PMMA) is commonly used in implant dentistry for the fabrication of implant-supported interim prostheses and as milled or 3D printed prototypes. This article describes a novel protocol to prosthetically restore a completely edentulous patient following a digital workflow, with fixed, screw-retained, implant-supported prostheses fabricated from CAD/CAM milled polymethyl methacrylate (PMMA), with no metal substructure. After two years follow up in terms of esthetics, phonetics, function and biological tissue response, the outcome remains functional and free of mechanical, biomechanical or biological complications. The aim of this article is to illustrate the feasibility of using milled PMMA as viable definitive prosthetic material for the fixed implant rehabilitation of edentulous patients.

Evaluating the clinical behavior of veneered zirconia in comparison with monolithic zirconia complete arch implant-supported prostheses: A systematic review and meta-analysis.

STATEMENT OF PROBLEM: Because the use of zirconia in dentistry is relatively new, the number of published studies on the subject is scarce, even though material selection is an important factor in clinical performance. Therefore, a systematic assessment of the impact of the prosthetic material, framework design, veneering material, and manufacturing process is required. PURPOSE: The purpose of this systematic review and meta-analysis was to investigate the survival and success rates of feldspathic porcelain veneered zirconia (VZir) in comparison with monolithic zirconia (MZir) complete arch implant-supported prostheses (CAISPs). A secondary objective was to assess the influence of the type of loading, the presence or absence of a cantilever, the type of zirconia used, the location, and the opposing arch on complications rates and patient satisfaction. MATERIAL AND METHODS: An electronic search of the MEDLINE database (via PubMed), Scopus, Science Direct, Cochrane Library, and OpenGrey was carried out. The criteria described in the preferred reporting items for systematic reviews and meta-analyses statement were used. The search was restricted from January 2000 to January 2022. RESULTS: The systematic search resulted in 20 articles that met the established criteria. In total, 751 patients (VZir=302; MZir=449) with 3038 CAISPs (VZir=368; MZir=2670) were analyzed. Higher prosthetic survival and success rates were found in MZir compared with VZir CAISPs (100% and 95.45%, respectively). The meta-analysis found significantly fewer complications related to MZir (9.4% [4.8%-14.1%]) compared with VZir (33.7% [17.5%-49.9%]). CONCLUSIONS: Based on the findings of this systematic review, MZir CAISPs had higher survival and success rates than VZir CAISPs, with significantly fewer prosthetic complications. The influence of factors such as the type of functional loading, the presence of a cantilever, the material used in the prosthodontic workflow, the location of the CAISP, and the type of antagonist arch on the performance of Zir CAISPs remains unclear.

Selection criteria for immediate implant placement and immediate loading for single tooth replacement in the maxillary esthetic zone: A systematic review and meta-analysis.

OBJECTIVES: The aim of this study was to review available evidence for Type 1A (immediate implant placement and immediate loading) of single tooth replacement in the maxillary esthetic zone. MATERIALS AND METHODS: An electronic search was conducted utilizing the databases of MEDLINE, Embase, and Cochrane to identify publications reporting on the outcomes of Type 1A for single tooth replacement in the maxillary esthetic zone. The success and survival rates of the included articles were reported, which were further categorized according to the clinical criteria reported in Type 1A. Mean survival rates were univariately compared between risk groups and additionally between studies published before and since 2012 using bias-corrected and study size-weighed bootstrap tests. A study time-correcting meta-analysis was then performed to obtain an overall effect for the study pool. RESULTS: A total of 3118 publications were identified in the search, with a total of 68 articles included. A mean number of implants per study were 37.2 and mean follow-up was 2.8 years. All the included studies utilizing Type 1A report highly selective inclusion and exclusion criteria. Univariate risk group comparison determined that studies before 2012 report a significantly lower mean survival rate (difference of -1.9 percentage points [PP], 95% CI: [-0.3, -4.0], p = .02), facial gap dimension had an impact on survival rates (+3.1 PP [0.2, 5.3] for width >2 mm, p = .04), as well as presence of endodontic infection (+2.6 PP [0.9, 5.1], p = .004). CONCLUSIONS: Type 1A has a high survival rate in studies reporting strict patient and site selection criteria. Further research is required to assess esthetic and functional success with Type 1A treatments.

Clinical performance of immediately placed and immediately loaded single implants in the esthetic zone: A systematic review and meta-analysis.

OBJECTIVES: The aim of this study was to assess the following PIO question: In adult patients treated with an indication for single tooth extraction in the maxillary esthetic zone (15-25), what is the influence of an immediate implant placement and immediate loading protocol on the clinical performance (primary aim) and esthetic outcomes (secondary aim) focusing on investigations published after 2010. MATERIAL AND METHODS: An electronic search in Medline (PubMed), the Cochrane Central Register of Controlled Trials, and EMBASE databases up to April 2022 was performed to identify clinical studies investigating the outcome of single implants subjected to immediate placement with immediate restoration/loading (Type 1A). RESULTS: Sixty-three studies (10 randomized controlled trials, 28 prospective and 25 retrospective cohort studies) were included with a follow-up ranging from 12 to 96 months. One thousand nine hundred sixty-one implants reported survival rates of 99.2 (98.6-99.5) % at 1 year, 97.5 (95.9-98.4) % after 3 years, and 95.8 (93.3-97.4) % after 5 years; 1064 immediately loaded restorations presented survival rates of 98.9 (97.8-99.5) % after 1 year, 96.8 (93.6-98.4) % after 2 years, and 94.8 (89.6-97.4) % after 5 years. Comparing baseline to 12-month data using the Hedges' g effect size (95% CI), papilla height presented an overall effect size of -0.71 (-1.25, -0.1) mm, midfacial recession change of -0.15 (-0.66, 0.36) mm, and a 0.82 (0.37, 1.28) gain in PES. CONCLUSIONS: Immediate implant placement and immediate loading can be considered a predictable and safe treatment option for single maxillary anterior restorations with adequate survival rates and favorable esthetics outcomes for up to 5 years.

Intraoral digital implant scans: Parameters to improve accuracy.

PURPOSE: To report the means to maximize the predictability and accuracy of intraoral digital implant scans through the evaluation of operator and patient-related factors. MATERIALS AND METHODS: A search of published articles related to factors that can decrease the scanning accuracy of intraoral digital implant scans was completed in four data sources:MEDLINE, EMBASE, EBSCO, and Web of Science. All studies related to variables that can influence the accuracy of intraoral digital implant scans obtained by using intraoral scanners (IOSs) were considered. These variables included ambient lighting, scanning pattern, implant scan body (ISB) design, techniques for splinting ISBs, arch location, implant position, and inter-implant distance. RESULTS: Among operator-related factors, ambient lighting conditions, scanning pattern, and ISB design (material, geometry, and retention design) can impact the accuracy of intraoral digital implant scans. The optimal ISB for maximizing IOS accuracy is unclear; however, polymer ISB can wear with multiple reuse and sterilization methods. Among patient-related factors, additional variables should be considered, namely arch (maxillary vs. mandibular arch), implant position in the arch, inter-implant distance, implant depth, and angulation. CONCLUSIONS: Ambient lighting conditions should be established based on the IOS selected to optimize the accuracy of intraoral digital implant scans. The optimal scanning pattern may vary based on the IOS, clinical situation, and the number of implants. The optimal ISB design may vary depending on the IOS used. Metallic implant scan bodies are preferred over polymer ISB designs to minimize wear due to multiple use and sterilization distortion. Among patient-related factors, additional variables should be considered namely the arch scanned, implant position in the arch, inter-implant distance, implant depth, and angulation. The impact of these factors may vary depending on the IOS selected.

Accuracy of complete-arch digital implant impression with intraoral optical scanning and stereophotogrammetry: An in vivo prospective comparative study.

OBJECTIVES: To assess accuracy of intraoral optical scanning (IOS) and stereophotogrammetry (SPG), complete-arch digital implant impressions in vivo. MATERIALS AND METHODS: Consecutive patients needing implant-supported screw-retained zirconia complete-arch fixed-dental prostheses (ISZ-FDP) were recruited. For each patient, three impressions were taken: IOS, SPG (tests), and open-tray plaster (reference). Linear (ΔX, ΔY, and ΔZ), three-dimensional (ΔEUC), and angular deviations (ΔANGLE) were evaluated and stratified according to scanning technology for each implant. Potential effects of impression device (IOS and SPG), arch (maxilla and mandible), and implant number (4 and 6) were evaluated through multivariable analysis. Significance level was set at .05. RESULTS: A total of 11 complete arches (5 maxillae, 6 mandibles) in 11 patients were rehabilitated with ISZ-FDPs supported by 4 (n = 8) and 6 implants (n = 3). A total of 50 implants and 100 implant positions were captured by two investigated devices and compared to respective reference (mean ΔEUC IOS 137.2, SPG 87.6 µm; mean ΔANGLE 0.79, 0.38°). Differences between measurements (SPG-IOS) were computed for each implant, with negative values indicating better SPG accuracy. Significant mean ΔEUC difference of -49.60 µm (p = .0143; SD 138.15) and mean ΔANGLE difference of -0.40° (p < .0001; SD 0.65) were observed in favor of SPG. Multivariable analysis showed significant effect on ΔEUC (p = .0162) and ΔANGLE (p = .0001) only for impression devices, with SPG performing better. CONCLUSIONS: SPG experienced significantly higher linear and angular accuracy. No effect of type of arch or implant number was detected. Higher extreme deviations were experienced for IOS. SPG can be feasible for complete-arch digital impressions with caution, and rigid prototype try-in is recommended before screw-retained prosthesis manufacturing.

Immunogenicity and In Vivo Protective Effects of Recombinant Nucleocapsid-Based SARS-CoV-2 Vaccine Convacell®.

The vast majority of SARS-CoV-2 vaccines which are licensed or under development focus on the spike (S) protein and its receptor binding domain (RBD). However, the S protein shows considerable sequence variations among variants of concern. The aim of this study was to develop and characterize a SARS-CoV-2 vaccine targeting the highly conserved nucleocapsid (N) protein. Recombinant N protein was expressed in Escherichia coli, purified to homogeneity by chromatography and characterized by SDS-PAGE, immunoblotting, mass spectrometry, dynamic light scattering and differential scanning calorimetry. The vaccine, formulated as a squalane-based emulsion, was used to immunize Balb/c mice and NOD SCID gamma (NSG) mice engrafted with human PBMCs, rabbits and marmoset monkeys. Safety and immunogenicity of the vaccine was assessed via ELISA, cytokine titer assays and CFSE dilution assays. The protective effect of the vaccine was studied in SARS-CoV-2-infected Syrian hamsters. Immunization induced sustainable N-specific IgG responses and an N-specific mixed Th1/Th2 cytokine response. In marmoset monkeys, an N-specific CD4+/CD8+ T cell response was observed. Vaccinated Syrian hamsters showed reduced lung histopathology, lower virus proliferation, lower lung weight relative to the body, and faster body weight recovery. Convacell® thus is shown to be effective and may augment the existing armamentarium of vaccines against COVID-19.

Prevention and management of peri-implant disease.

BACKGROUND: As more patients choose dental implants as their primary treatment option to restore edentulous ridges or to replace compromised dentition, preventive strategies for peri-implant diseases and complications have become an important topic. PURPOSE: The aim of the review article is to summarize the current available evidence on the potential risk factors/indicators for peri-implant disease development and then focus on the preventive strategies for peri-implant diseases and conditions. MATERIALS AND METHODS: After reviewing the diagnostic criteria and the etiology of peri-implant diseases and conditions, evidence on the possible associated risk factors/indicators for peri-implant diseases were searched and identified. Recent studies were also surveyed to explore the preventive measures for peri-implant diseases. RESULTS: The possible associated risk factors of peri-implant diseases can be divided into the following categories: patient-specific factors, implant-specific factors, and long-term factors. Patient-specific factors such as history of periodontitis and smoking have been conclusively associated with peri-implant diseases, whereas findings on others, such as diabetes and genetic factors, remain inconclusive. It has been suggested that both implant-specific factors, such as implant position, soft tissue characteristics, and the type of connection used, and long-term factors, such as poor plaque control and a lack of maintenance program, have a strong impact on maintaining the health of a dental implant. Assessment tool for evaluating the risk factors can be a potential preventive measure for peri-implant disease prediction, and it is needed to be properly validated. CONCLUSION: Proper maintenance program for early intervention to control peri-implant diseases at the initial stage and pretreatment assessment of the potential risk factors is the best strategy to prevent implant diseases.

Multifunctional anatomical prototypes (MAPs): Treatment of excessive gingival display due to altered passive eruption.

OBJECTIVE: To describe a strategy using digital technologies for improving the diagnosis, treatment planning, and surgical execution of patients with excessive gingival display (EGD) due to altered passive eruption (APE). CLINICAL CONSIDERATIONS: An important component for successful patient's management is to fulfill their esthetic expectations whilst delivering predictable and long-term therapeutic outcomes. To achieve this goal in patients with excessive gingival display due to altered passive eruption, it is essential to perform an accurate diagnosis and to communicate to the patient the expected customized results using digital technologies. Computer-aided designed and manufactured multifunctional anatomical prototypes (MAPs) may contribute to these purposes. Additionally, they can guide the surgical crown lengthening procedure or serve as a reference during the surgical guide fabrication providing information of the required anatomical landmarks. CONCLUSIONS: This novel strategy protocol for diagnosis, communication, and treatment management of patients with excessive gingival display follows functional and biological principles within the frame of a digital workflow, which improves the diagnostic capabilities, enhances communication, and guides the surgical treatment as shown in the 12 months follow-up of the reported case. CLINICAL SIGNIFICANCE: Developing a virtual patient by combining multiple digital data sets including cone-beam computed tomography (CBCT), intra-oral scans and digital photography, supports the clinician and the patient to achieve a comprehensive diagnosis and to better communicate the expected results to the patient. Furthermore, this digital treatment exercise based on anatomical and biological principles will facilitate the surgical precision and the achievement of successful outcomes, thus fulfilling the patient needs and expectations.

Contour angle and peri-implant tissue height: Two interrelated features of the implant supracrestal complex.

OBJECTIVES: Recent research has suggested the contour of the prosthesis and the vertical height of the peri-implant mucosa as important parameters that can influence the long term health and stability of the peri-implant tissue. In particular, overcontouring of the prosthesis has been correlated with an increased risk for peri-implantitis, while reduced soft tissue height has been associated with marginal bone loss, recession, and other soft tissue complications. Although these two parameters have been investigated as independent in the current literature, clinical experience points toward a close interrelation between transmucosal tissue height and prosthesis contour angle. It is often found that a reduced vertical height of the implant supracrestal complex is the main reason for overcontouring of the prosthesis. At the same time, achieving a favorable contour of 30o or less is not possible unless the clinician has ensured an adequate vertical height of the soft tissue. The purpose of this short communication is to establish the relation between tissue vertical height and prosthesis contour by utilizing a theoretical geometry equation based on the Pythagorean theorem. In doing so, one can use the dimensions of the implant as well as those of the prosthesis at the mucosal margin to calculate the essential vertical height for achieving a favorable prosthesis contour. CONCLUSIONS: As the treatment plan of the implant supracrestal complex is "top-down," in case of deficient vertical height, subcrestal placement of the implant should be considered to achieve a proper prosthesis contour.

Application of 3D-printed guide for locating screw access channels in cement-retained complete arch implant-supported zirconia restorations.

Removal of cement-retained complete arch implant-supported zirconia restorations can be challenging. A predictable and minimally invasive technique combining cone beam computed tomography (CBCT) and intraoral scans with a virtual implant planning software program is described to identify the location of the screw access channels during the retrieval, thus minimizing damage to the existing restoration and allowing reuse.