An overview of three-dimensional imaging devices in dentistry.

OBJECTIVE: To review four types of three-dimensional imaging devices: intraoral scanners, extraoral scanners, cone-beam computed tomography (CBCT), and facial scanners, in terms of their development, technologies, advantages, disadvantages, accuracy, influencing factors, and applications in dentistry. METHODS: PubMed (National Library of Medicine) and Google Scholar databases were searched. Additionally, the scanner manufacturers' websites were accessed to obtain relevant data. Four authors independently selected the articles, books, and websites. To exclude duplicates and scrutinize the data, they were uploaded to Mendeley Data. In total, 135 articles, two books, and 17 websites were included. RESULTS: Research and clinical practice have shown that oral and facial scanners and CBCT can be used widely in various areas of dentistry with high accuracy. CONCLUSION: Although further advancement of these devices is desirable, there is no doubt that digital technology represents the future of dentistry. Furthermore, the combined use of different devices may bring dentistry into a new era. These four devices will play a significant role in clinical utility with high accuracy. The combined use of these devices should be explored further. CLINICAL SIGNIFICANCE: The four devices will play a significant role in clinical use with high accuracy. The combined use of these devices should be explored further.

Zn and Ag Doping on Hydroxyapatite: Influence on the Adhesion Strength of High-Molecular Polymer Polycaprolactone.

In this study, density functional theory was employed to calculate the adsorption of polycaprolactone (PCL) by pure hydroxyapatite (HA), Zn-doped HA, and Ag-doped HA, and the interaction of PCL on the surface of HA (001) was simulated. The results show that there was significant electron transfer between the carbonyl O in PCL and the Zn, Ag, and Ca in HA, forming coordinate bonds. The binding energies of Ag-doped HA/PCL and Zn-doped HA/PCL were much higher than those of HA/PCL. HA doped with Ag had the highest binding energy to PCL. Therefore, we believe that when HA is doped with Ag atoms, its adsorption capacity for PCL can be increased. The results obtained in this study can be used as a guide for the development of HA/PCL bone graft composite material doped with appropriate metal ions to improve its adsorption capacity.

A Six-Year Prospective Comparative Study of Wide and Standard Diameter Implants in the Maxillary and Mandibular Posterior Area.

Background and Objectives: The aim of our study was to test whether wide diameter (6 mm) implants perform differently from standard diameter (4 mm) implants in terms of marginal bone level and survival rate. Materials and Methods: Our sample comprised 72 patients who underwent surgery; a total of 80 implants were placed in the maxillary or mandibular molar region. Patients were divided into two groups according to the diameter of the implant, and were followed up for six years after the final setting of the prosthetics. In the test group, 40 implants with 6-mm diameter were inserted; in the control group, 40 standard diameter implants were inserted. Using panoramic radiographs, we investigated mesial and distal marginal bone levels around the implant fixtures. Results: After the first implant surgery, three implants, including one wide diameter and two standard diameter implants, failed due to lack of osseointegration. We did not note any fixture fracture during the six-year follow-up. After loading, we observed a six-year survival rate of 97.29% with no statistically significant difference from standard diameter implants, with a survival rate of 94.87%. Conclusions: This study shows that 6-mm diameter implants may be considered in the presence of adequate alveolar ridge width in the posterior maxillary and mandibular regions.

Effect of Decompression on Jaw Cystic Lesions Based on Three-Dimensional Volumetric Analysis.

Background and objectives: This study aimed to evaluate the effectiveness of decompression on jaw cysts according to various parameters by volumetric analysis using three-dimensional computed tomography. Materials and methods: Fifty patients who underwent surgical decompression of the jaw cystic lesion were selected, and their preoperative and postoperative computed tomography results between 3 and 27 months were collected. Volumetric analysis was performed to evaluate any differences in the rate of volumetric change according to the sex, age, initial volume of the lesion, duration, location of the lesion, tooth extraction, expansion of the cortical layer, and pathological diagnosis. Multiple linear regression and generalised linear mixed models were used for statistical analyses. Results: The mean reduction rate among all patients was 54.68%. Multiple linear regression analysis revealed that higher reduction rates were associated with a long decompression period, young patient age, and location of the cyst in the posterior maxilla. Generalised linear mixed models revealed that higher reduction rates were associated with a long decompression period and young patient age. Conclusions: Decompression was an effective treatment for reducing the cyst size in all patients. Its effectiveness increased with a long treatment duration, young patient age, and cyst location in the posterior maxilla three-dimensionally.

Improved PCR assay for the species-specific identification and quantitation of Legionella pneumophila in water.

Legionellosis outbreak is a major global health care problem. However, current Legionella risk assessments may be compromised by uncertainties in Legionella detection methods, infectious dose, and strain infectivity. These limitations may place public health at significant risk, leading to significant monetary losses in health care. However, there are still unmet needs for its rapid identification and monitoring of legionellae in water systems. Therefore, in the present study, a primer set was designed based on a LysR-type transcriptional regulator (LTTR) family protein gene of Legionella pneumophila subsp. pneumophila str. Philadelphia 1 because it was found that this gene is structurally diverse among species through BLAST searches. The specificity of the primer set was evaluated using genomic DNA from 6 strains of L. pneumophila, 5 type strains of other related Legionella species, and other 29 reference pathogenic bacteria. The primer set used in the PCR assay amplified a 264-bp product for only targeted six strains of L. pneumophila. The assay was also able to detect at least 1.39 × 10(3) copies/µl of cloned amplified target DNA using purified DNA or 7.4 × 10(0) colony-forming unit per reaction when using calibrated cell suspension. In addition, the sensitivity and specificity of this assay were confirmed by successful detection of Legionella pneumophila in environmental water samples.

A Simplified GBR Treatment and Evaluation of Posterior Seibert Class I Ridge Defects via Bio-collagen and Platelet-Rich Fibrin: A Retrospective Study.

BACKGROUND: Classical guided bone regeneration (GBR) treatments can achieve favorable clinical results for ridge defects. However, extensive bone augmentation in the non-esthetic area in the posterior region for minor ridge defects is unnecessary. Therefore, this study used a collagen and Platelet-rich fibrin (PRF) mixture for bone augmentation on minor posterior ridge defects and evaluated the effects. METHODS: 22 Seibert Class I ridge defects were treated with BC and covered with a PRF membrane (simplified guided bone regeneration, simplified GBR) and other 22 were treated with Bio-Oss and covered with Bio-Gide (classical GBR). Cone-beam computed tomography imaging was conducted 6 months post-surgery to compare the ridge's horizontal width (HW) and buccal ridge's horizontal width to assess the osteogenic effect. In addition, the buccal ridge contour morphology was studied and classified. RESULTS: The buccal ridge contour of simplified GBR was Type A in 14 cases, Type B in 7 cases, and Type C in 1 case and it of classical GBR was Type A in 11 cases, Type B in 8 cases, and Type C in 3 cases. The mean HW significantly increased by 1.50 mm of simplified GBR treatment, while it increased by 1.83 mm in classical GBR treatment. CONCLUSION: The combined use of BC and PRF had a significant effect on bone augmentation and this treatment exhibited promising clinical results for correcting posterior Seibert Class I ridge defects. The morphological classification of the reconstructive effect in this study can be utilized in future clinical work.

Cross-Disciplinary Application for Qualitative Magnesium Corrosion Assays.

At the moment, unserviceable magnesium implants make a good case in point for further responsible study in this field. Whether we are willing to admit it or not, existing methods for corrosion monitoring are exposed to susceptibility and instability. Interdisciplinary theories and the existing corrosion experiments were combined based on their various merits for developing an accurate and precise corroding experiment for Mg/Mg alloys. We used the water-soluble tetrazolium-8 (WST-8) reagent to further complete the immersion experiment. The color change of the solution reflects the rationale of corrosion, followed by monitoring the degree of corrosion. The feasibility of this idea will be demonstrated.

Sorption Studies of Tetracycline Antibiotics on Hydroxyapatite (001) Surface-A First-Principles Insight.

Owing to the limitations of traditional systemic drug delivery in the treatment of bone diseases with side effects on normal cells, the selection of materials with high affinities for bones, as targeting ligands to modify drug carriers, has become an important research topic. Tetracyclines (TCs) have an adsorption effect on hydroxyapatite (HAp). Thus, they can be used as bone-targeting ligands and combined with drug carriers. In this study, density functional theory is used to analyze the interaction mechanism of TC, oxytetracycline (OTC), chlortetracycline, and HAp. We calculate the electrostatic potential (ESP) and molecular orbitals to predict the possible binding sites of TCs on the HAp surface. The adsorption energy is used to compare the affinities of the three TCs to HAp. An independent gradient model analysis is performed to study the weak interaction between TCs and HAp. The coordination bond between TCs and the HAp surface is evaluated by conducting a charge density difference analysis. The results show that OTC has the highest affinity to HAp because the introduction of hydroxyl groups change the adsorption configuration of OTC. Thus, OTC adsorbed on HAp in a broken-line shape exposes more binding sites. This study provides a theoretical basis for TCs as bone-targeting ligands in treating bone diseases and in improving the safety of treatment by selecting different bone-targeting ligands.

Clinical Reference Strategy for the Selection of Treatment Materials for Maxillofacial Bone Transplantation: A Systematic Review and Network Meta-Analysis.

Bone graft materials have mixed effects of bone repair in the field of oral maxillofacial surgery. The qualitative analyses performed by previous studies imply that autogenous odontogenic materials and autogenous bone have similar effects on bone repair in clinical jaw bone transplantation. This retrospective systematic assessment and network meta-analysis aimed to analyze the best effect of clinical application of autogenous odontogenic materials and autogenous, allogeneic, and xenogeneic bone grafts in bone defect repair. A systematic review was performed by searching the PubMed, Cochrane Library, and other journal databases using selected keywords and Medical Subject Headings search terms. 10 Papers (n = 466) that met the inclusion criteria were selected. The assessment of heterogeneity did not reveal any overall statistical difference or heterogeneity (P = 0.051 > 0.05), whereas the comparison between autogenous and allogeneic bone grafts revealed local heterogeneity (P = 0.071 < 0.1). Risk of bias revealed nine unclear studies and one high-risk study. The overall consistency was good (P = 0.065 > 0.05), and the local inconsistency test did not reveal any inconsistency. The publication bias was good. The confidence regarding the ranking of bone graft materials after GRADE classification was moderate. The effects on bone repair in the descending order were as follows: autogenous odontogenic materials, xenogeneic bone, autogenous bone, and allogeneic bone. This result indicates that the autogenous odontogenic materials displayed stronger effects on bone repair compared to other bone graft materials. Autogenous odontogenic materials have broad development prospects in oral maxillofacial surgery.

Overview of Several Typical Ceramic Materials for Restorative Dentistry.

With the development of ceramic technology, prosthodontic ceramics are becoming a useful option for improving esthetic outcomes in dentistry. In this paper, various ceramic materials were reviewed and evaluated, and their advantages and disadvantages and indications in oral prosthodontics were analyzed objectively. The properties of resin-based ceramics, polycrystalline ceramics, and silicate ceramics were compared and analyzed. Resin-based ceramics may replace other ceramic materials in the CAD/CAM field.

Poloxamer-Based Scaffolds for Tissue Engineering Applications: A Review.

Poloxamer is a triblock copolymer with amphiphilicity and reversible thermal responsiveness and has wide application prospects in biomedical applications owing to its multifunctional properties. Poloxamer hydrogels play a crucial role in the field of tissue engineering and have been regarded as injectable scaffolds for loading cells or growth factors (GFs) in the last few years. Hydrogel micelles can maintain the integrity and stability of cells and GFs and form an appropriate vascular network at the application site, thus creating an appropriate microenvironment for cell growth, nerve growth, or bone integration. The injectability and low toxicity of poloxamer hydrogels make them a noninvasive method. In addition, they can also be good candidates for bio-inks, the raw material for three-dimensional (3D) printing. However, the potential of poloxamer hydrogels has not been fully explored owing to the complex biological challenges. In this review, the latest progress and cutting-edge research of poloxamer-based scaffolds in different fields of application such as the bone, vascular, cartilage, skin, nervous system, and organs in tissue engineering and 3D printing are reviewed, and the important roles of poloxamers in tissue engineering scaffolds are discussed in depth.

Controllability of Graphene Oxide Doxorubicin Loading Capacity Based on Density Functional Theory.

Graphene can be used as a drug carrier of doxorubicin (DOX) to reduce the side effects of doxorubicin. However, there is limited research on the surface chemical modifications and biological effects of graphene oxide (GO). Therefore, it is necessary to explore the DOX affinity of different oxygen-containing functional groups in the graphene system. We constructed graphene system models and studied the structure and distribution of epoxy and hydroxyl groups on the carbon surface. Based on molecular dynamics simulations and density functional theory (DFT), we investigated the interaction between DOX and either pristine graphene or GO with different ratios of oxygen-containing groups. The hydroxyl groups exhibited a stronger affinity for DOX than the epoxy groups. Therefore, the DOX loading capacity of graphene systems can be adjusted by increasing the ratio of hydroxyl to epoxy groups on the carbon surface.

Advances in Modification Methods Based on Biodegradable Membranes in Guided Bone/Tissue Regeneration: A Review.

Guided tissue/bone regeneration (GTR/GBR) is commonly applied in dentistry to aid in the regeneration of bone/tissue at a defective location, where the assistive material eventually degrades to be substituted with newly produced tissue. Membranes separate the rapidly propagating soft tissue from the slow-growing bone tissue for optimal tissue regeneration results. A broad membrane exposure area, biocompatibility, hardness, ductility, cell occlusion, membrane void ratio, tissue integration, and clinical manageability are essential functional properties of a GTR/GBR membrane, although no single modern membrane conforms to all of the necessary characteristics. This review considers ongoing bone/tissue regeneration engineering research and the GTR/GBR materials described in this review fulfill all of the basic ISO requirements for human use, as determined through risk analysis and rigorous testing. Novel modified materials are in the early stages of development and could be classified as synthetic polymer membranes, biological extraction synthetic polymer membranes, or metal membranes. Cell attachment, proliferation, and subsequent tissue development are influenced by the physical features of GTR/GBR membrane materials, including pore size, porosity, and mechanical strength. According to the latest advances, key attributes of nanofillers introduced into a polymer matrix include suitable surface area, better mechanical capacity, and stability, which enhances cell adhesion, proliferation, and differentiation. Therefore, it is essential to construct a bionic membrane that satisfies the requirements for the mechanical barrier, the degradation rate, osteogenesis, and clinical operability.

Diagnosis, Prevention, and Treatment of Radiotherapy-Induced Xerostomia: A Review.

In patients with head and neck cancer, irradiation (IR)-sensitive salivary gland (SG) tissue is highly prone to damage during radiotherapy (RT). This leads to SG hypofunction and xerostomia. Xerostomia is defined as the subjective complaint of dry mouth, which can cause other symptoms and adversely affect the quality of life. In recent years, diagnostic techniques have constantly improved with the emergence of more reliable and valid questionnaires as well as more accurate equipment for saliva flow rate measurement and imaging methods. Preventive measures such as the antioxidant MitoTEMPO, botulinum toxin (BoNT), and growth factors have been successfully applied in animal experiments, resulting in positive outcomes. Interventions, such as the new delivery methods of pilocarpine, edible saliva substitutes, acupuncture and electrical stimulation, gene transfer, and stem cell transplantation, have shown potential to alleviate or restore xerostomia in patients. The review summarizes the existing and new diagnostic methods for xerostomia, along with current and potential strategies for reducing IR-induced damage to SG function. We also aim to provide guidance on the advantages and disadvantages of the diagnostic methods. Additionally, most prevention and treatment methods remain in the stage of animal experiments, suggesting a need for further clinical research, among which we believe that antioxidants, gene transfer, and stem cell transplantation have broad prospects.

Allogeneic Demineralized Dentin Matrix as rhBMP-2 Carrier: A Retrospective Clinical Study.

PURPOSE: To compare the clinical outcomes of autogenous and allogeneic demineralized dentin matrices loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2; auto- and allo-DDM/rhBMP-2) by measuring the buccal marginal bone resorption around dental implants. MATERIALS AND METHODS: This retrospective study included patients who underwent dental implant placement with auto-DDM/rhBMP-2 as the control group and allo-DDM/rhBMP-2 as the experimental group. The primary outcome was buccal marginal bone resorption on CBCT. The resorption was calculated during T0 (from surgery to prosthetic loading), T1 (during the first year after loading), and T2 (during the second year after loading). The secondary outcome was the histologic analysis of five specimens of each group, obtained during the prosthetic procedure. RESULTS: Among the 103 implants, 61 and 42 implants were placed with auto- and allo-DDM/rhBMP-2 matrices, respectively. The resorptions of all periods were similar between the groups (T0: 0.65 ± 0.71 and 0.67 ± 0.81 mm, T1: 0.55 ± 0.60 and 0.59 ± 0.81 mm, and T2: 0.29 ± 0.45 and 0.20 ± 0.30 mm with auto- and allo-DDM/rhBMP-2, respectively). The histologic and histomorphometric analysis revealed similar osteoinductive aspects and proportions of new bone between the groups. CONCLUSION: Allo-DDM/rhBMP-2 showed comparable outcomes in terms of buccal marginal bone resorption to auto-DDM/rhBMP-2 during the second year after loading.

Effect of Different Membranes on Vertical Bone Regeneration: A Systematic Review and Network Meta-Analysis.

This study is aimed at performing a systematic review and a network meta-analysis of the effects of several membranes on vertical bone regeneration and clinical complications in guided bone regeneration (GBR) or guided tissue regeneration (GTR). We compared the effects of the following membranes: high-density polytetrafluoroethylene (d-PTFE), expanded polytetrafluoroethylene (e-PTFE), crosslinked collagen membrane (CCM), noncrosslinked collagen membrane (CM), titanium mesh (TM), titanium mesh plus noncrosslinked (TM + CM), titanium mesh plus crosslinked (TM + CCM), titanium-reinforced d-PTFE, titanium-reinforced e-PTFE, polylactic acid (PLA), polyethylene glycol (PEG), and polylactic acid 910 (PLA910). Using the PICOS principles to help determine inclusion criteria, articles are collected using PubMed, Web of Science, and other databases. Assess the risk of deviation and the quality of evidence using the Cochrane Evaluation Manual, and GRADE. 27 articles were finally included. 19 articles were included in a network meta-analysis with vertical bone increment as an outcome measure. The network meta-analysis includes network diagrams, paired-comparison forest diagrams, funnel diagrams, surface under the cumulative ranking curve (SUCRA) diagrams, and sensitivity analysis diagrams. SUCRA indicated that titanium-reinforced d-PTFE exhibited the highest vertical bone increment effect. Meanwhile, we analyzed the complications of 19 studies and found that soft tissue injury and membrane exposure were the most common complications.

Fluoride Coatings on Magnesium Alloy Implants.

After several years of research and development, it has been reported that magnesium alloys can be used as degradable metals in some medical device applications. Over the years, fluoride coatings have received increasing research attention for improving the corrosion resistance of magnesium. In this paper, different methods for preparing fluoride coatings and the characteristics of these coatings are reported for the first time. The influence of the preparation conditions of fluoride coatings, including the magnesium substrate, voltage, and electrolyte, on the coatings is discussed. Various properties of magnesium fluoride coatings are also summarized, with an emphasis on corrosion resistance, mechanical properties, and biocompatibility. We screened experiments and papers that planned the application of magnesium fluoride coatings in living organisms. We have selected the literature with the aim of enhancing the performance of in vivo implants for reading and further detailed classification. The authors searched PubMed, SCOPUS, Web of Science, and other databases for 688 relevant papers published between 2005 and 2021, citing 105 of them. The selected time range is the last 16 years. Furthermore, this paper systematically discusses future prospects and challenges related to the application of magnesium fluoride coatings to medical products.

Research of weak interaction between water and different monolayer graphene systems.

Weak interactions play a very important role in the fields of supramolecular chemistry, molecular physics, materials science, etc. They have a great impact on the structure of the compounds in the gas, liquid and solid phases and the mechanism of some reaction processes. In this study, we visualized the intermolecular interactions between H2O and different graphene systems through density functional theory. Because the surface of Graphene oxide (GO) has epoxy groups, hydroxyl groups, and other oxygen-containing groups. These groups are prone to hydrogen bonding with hydrogen atoms of H2O, and we further explain some of them based on the acid-base theory. Also, we obtained the components of interactions between different graphene complex and H2O by energy decomposition. Then we found that for systems with moderate strength hydrogen bonding, such as hydroxyl functional group systems, electrostatic attraction is dominant while the dispersion attraction and induction function play an auxiliary role together.

A Review of 3D Printing in Dentistry: Technologies, Affecting Factors, and Applications.

Three-dimensional (3D) printing technologies are advanced manufacturing technologies based on computer-aided design digital models to create personalized 3D objects automatically. They have been widely used in the industry, design, engineering, and manufacturing fields for nearly 30 years. Three-dimensional printing has many advantages in process engineering, with applications in dentistry ranging from the field of prosthodontics, oral and maxillofacial surgery, and oral implantology to orthodontics, endodontics, and periodontology. This review provides a practical and scientific overview of 3D printing technologies. First, it introduces current 3D printing technologies, including powder bed fusion, photopolymerization molding, and fused deposition modeling. Additionally, it introduces various factors affecting 3D printing metrics, such as mechanical properties and accuracy. The final section presents a summary of the clinical applications of 3D printing in dentistry, including manufacturing working models and main applications in the fields of prosthodontics, oral and maxillofacial surgery, and oral implantology. The 3D printing technologies have the advantages of high material utilization and the ability to manufacture a single complex geometry; nevertheless, they have the disadvantages of high cost and time-consuming postprocessing. The development of new materials and technologies will be the future trend of 3D printing in dentistry, and there is no denying that 3D printing will have a bright future.

Microcomputed Tomography and Histological Study of Bone Regeneration Using Tooth Biomaterial with BMP-2 in Rabbit Calvarial Defects.

Our study was aimed to analyze the osteoinductive effect of powdered and block type autogenous bone graft along with bone morphogenetic protein (BMP-2) as compared to synthetic bone graft. Three circular bicortical defects were made in the calvaria of each rabbit and randomly divided into three groups as follows: powdered tooth biomaterial+BMP-2, block tooth biomaterial+BMP-2, and control group: synthetic bone+BMP-2. The samples taken from these defects after 4 and 8 weeks were analyzed histologically along with micro CT analysis. In our study, both powered and block type tooth autogenous bone graft successfully stimulated mesenchymal cells leading to endochondral ossification and bone regeneration. We observed that the powered bone graft material which is acid insoluble especially is preferable as a carrier for BMP-2.