Automated scoring and augmented reality visualization software program for evaluating tooth preparations.

STATEMENT OF PROBLEM: Tooth preparation is an essential part of prosthetic dentistry; however, traditional evaluation methods involve subjective visual inspection that is prone to examiner variability. PURPOSE: The purpose of this study was to investigate a newly developed automated scoring and augmented reality (ASAR) visualization software program for evaluating tooth preparations. MATERIAL AND METHODS: A total of 122 tooth models (61 anterior and 61 posterior teeth) prepared by dental students were evaluated by using visual assessments that were conducted by students and an expert, and auto assessment that was performed with an ASAR software program by using a 3-dimensional (3D) point-cloud comparison method. The software program offered comprehensive functions, including generating detailed reports for individual test models, producing a simultaneous summary score report for all tested models, creating 3D color-coded deviation maps, and forming augmented reality quick-response (AR-QR) codes for online data storage with AR visualization. The reliability and efficiency of the evaluation methods were measured by comparing tooth preparation assessment scores and evaluation time. The data underwent statistical analysis using the Kruskal-Wallis test, followed by Mann-Whitney U tests for pairwise comparisons adjusted with the Benjamini-Hochberg method (α=.05). RESULTS: Significant differences were found across the evaluation methods and tooth types in terms of preparation scores and evaluation time (P<.001). A significant difference was observed between the auto- and student self-assessment methods (P<.001) in scoring both the anterior and posterior tooth preparations. However, no significant difference was found between the auto- and expert-assessment methods for the anterior (P=.085) or posterior (P=.14) tooth preparation scores. Notably, the auto-assessment method required significantly shorter time than the expert- and self-assessment methods (P<.001) for both tooth types. Additionally, significant differences in evaluation time between the anterior and posterior tooth were observed in both self- and expert-assessment methods (P<.001), whereas the evaluation times for both the tooth types with the auto-assessment method were statistically similar (P=.32). CONCLUSIONS: ASAR-based evaluation is comparable with expert-assessment while exhibiting significantly higher time efficiency. Moreover, AR-QR codes enhance learning and training experiences by facilitating online data storage and AR visualization.

Effectiveness of virtual reality interactive simulation practice in prosthodontic education: A systematic review and meta-analysis.

INTRODUCTION: Virtual reality-based interactive simulation (VRIS) provides a safe and controlled environment for dental students and professionals to develop skills and knowledge. This study aimed to investigate the effectiveness of using the VRIS for prosthodontic practice and to explore the trends, application areas, and users' attitudes towards VRIS. MATERIALS AND METHODS: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for searching studies published until 21 March 2023 that reported quantitative or qualitative learning outcomes related to the use of VRIS for dental prosthodontic practice and clinical training. The quality of the included studies was assessed using the Medical Education Research Study Quality Instrument (MERSQI) and Newcastle-Ottawa Scale-Education (NOS-E) tools. A random-effects meta-analysis was conducted to compare the intervention group (utilizing VRIS) and the control group (employing conventional prosthodontic training methods) based on performance skill scores and task completion time, with a significance level set at <.05. RESULTS: The meta-analysis revealed that the utilization of VRIS generally improves students' performance scores (SMD = 1.04; 95% CI, -0.35 to 2.44; I2 > 50%; p = .13) and reduces task completion time (SMD = -0.03; 95% CI, 1.39-7.72; I2 > 50%; p = .93). Notably, using VRIS significantly enhanced the performance scores in implant surgery practice (SMD = 0.26; 95% CI, 0.09-0.42; p < .05). Additionally, the VRIS method significantly reduced task completion time in the cavity restorative preparation task (SMD = -1.19; 95% CI, -1.85 to -0.53; p < .05). CONCLUSION: Engaging in practice with VRIS has the potential to enhance learning proficiency in prosthodontic education. The advantages associated with VRIS encompass the provision of immediate feedback, decreased task completion time, heightened confidence and motivation, accelerated skill acquisition, improved performance scores, and increased learning engagement.

The human PTGR1 gene expression is controlled by TE-derived Z-DNA forming sequence cooperating with miR-6867-5p.

Z-DNA, a well-known non-canonical form of DNA involved in gene regulation, is often found in gene promoters. Transposable elements (TEs), which make up 45% of the human genome, can move from one location to another within the genome. TEs play various biological roles in host organisms, and like Z-DNA, can influence transcriptional regulation near promoter regions. MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that play a critical role in the regulation of gene expression. Although TEs can generate Z-DNA and miRNAs can bind to Z-DNA, how these factors affect gene transcription has yet to be elucidated. Here, we identified potential Z-DNA forming sequence (ZFS), including TE-derived ZFS, in the promoter of prostaglandin reductase 1 (PTGR1) by data analysis. The transcriptional activity of these ZFS in PTGR1 was confirmed using dual-luciferase reporter assays. In addition, we discovered a novel ZFS-binding miRNA (miR-6867-5p) that suppressed PTGR1 expression by targeting to ZFS. In conclusion, these findings suggest that ZFS, including TE-derived ZFS, can regulate PTGR1 gene expression and that miR-6867-5p can suppress PTGR1 by interacting with ZFS.

Identification of microRNAs Derived from Transposable Elements in the Macaca mulatta (Rhesus Monkey) Genome.

Transposable elements (TEs) are mobile DNA entities that can move within the host genome. Over long periods of evolutionary time, TEs are typically silenced via the accumulation of mutations in the genome, ultimately resulting in their immobilization. However, they still play an important role in the host genome by acting as regulatory elements. They influence host transcription in various ways, one of which as the origin of the generation of microRNAs (miRNAs), which are so-called miRNAs derived from TEs (MDTEs). miRNAs are small non-coding RNAs that are involved in many biological processes by regulating gene expression at the post-transcriptional level. Here, we identified MDTEs in the Macaca mulatta (rhesus monkey) genome, which is phylogenetically close species to humans, based on the genome coordinates of miRNAs and TEs. The expression of 5 out of 17 MDTEs that were exclusively registered in M. mulatta from the miRBase database (v22) was examined via quantitative polymerase chain reaction (qPCR). Moreover, Gene Ontology analysis was performed to examine the functional implications of the putative target genes of the five MDTEs.

Human Endogenous Retrovirus-H-Derived miR-4454 Inhibits the Expression of DNAJB4 and SASH1 in Non-Muscle-Invasive Bladder Cancer.

Although most human endogenous retroviruses (HERVs) have been silenced and lost their ability to translocate because of accumulated mutations during evolution, they still play important roles in human biology. Several studies have demonstrated that HERVs play pathological roles in numerous human diseases, especially cancer. A few studies have revealed that long non-coding RNAs that are transcribed from HERV sequences affect cancer progression. However, there is no study on microRNAs derived from HERVs related to cancer. In this study, we identified 29 microRNAs (miRNAs) derived from HERV sequences in the human genome. In particular, we discovered that miR-4454, which is HERV-H-derived miRNA, was upregulated in non-muscle-invasive bladder cancer (NMIBC) cells. To figure out the effects of upregulated miR-4454 in NMIBC, genes whose expression was downregulated in NMIBC, as well as tumor suppressor genes, were selected as putative target genes of miR-4454. The dual-luciferase assay was used to determine the negative relationship between miR-4454 and its target genes, DNAJB4 and SASH1, and they were confirmed to be promising target genes of miR-4454. Taken together, this study suggests that the upregulation of miR-4454 derived from HERV-H in NMIBC reduces the expression of the tumor suppressor genes, DNAJB4 and SASH1, to promote NMIBC progression.

Transcriptomic analysis of neutrophil apoptosis induced by diffuse large B-cell lymphoma unveils a potential role in neutropenia.

BACKGROUND: Diffuse large B-cell lymphoma (DLBCL) is an aggressive lymphoma that arises from malignant transformation of B lymphocytes. Outcome of patients with DLBCL has been significantly improved by rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy, which is regarded "gold standard" of DLBCL therapy. It is unfortunate that febrile neutropenia, a decrease of the neutrophil count in the blood accompanying fever, is one of the most common complications that DLBCL patients receiving R-CHOP regimen experience. Given the critical role of neutrophils against bacterial and fungal infections, neutropenia could be deadly. While the association between R-CHOP therapy and neutropenia has been well-established, the negative effect of DLBCL cells on the survival of neutrophils has not been clearly understood. Our previous study have shown that conditioned medium (CM) derived from Ly1 DLBCL cells induces apoptosis in murine neutrophils ex vivo. Additionally, Ly1 CM and doxorubicin synergize to further enhance apoptotic rate in neutrophils, possibly contributing to neutropenia in DLBCL patients. OBJECTIVE: We investigated the mechanism and genes that regulate neutrophil apoptosis induced by secretome of DLBCL cells, which would give insight into the potential role of DLBCL in neutropenia. METHOD: Murine neutrophils were isolated from bone marrow in C57BL6/J mice using flow cytometry. QuantSeq 3' mRNA-sequencing was conducted on neutrophils following exposure to CM derived from Ly1 DLBCL cells or murine bone marrow cells (control). Quantseq 3'mRNA sequencing data were aligned to identify differentially expressed mRNAs. Next, the expression of genes related to neutrophil apoptosis and proliferation were analyzed and Gene classification and ontology were analyzed. RESULT: We identified 1196 (198 upregulated and 998 downregulated) differentially expressed genes (DEGs) in Ly1 DLBCL co-culture group compared to the control group. The functional enrichment analyses of DEGs in co-culture group revealed significant enriched in apoptosis process, and immune system process in gene ontology and the highly enriched pathway of various bacterial infection, leukocyte transendothelial migration, apoptosis, and cell cycle in KEGG pathway. Importantly, Bcl7b, Bnip3, Bmx, Mcl1, and Pim1 were identified as critical regulators of neutrophil apoptosis, which may be potential drug targets for the treatment of neutropenia. We are currently testing the efficacy of the activators/inhibitors of the proteins encoded by these genes to investigate whether they would block DLBCL-induced neutrophil apoptosis. CONCLUSION: In the present study, bioinformatic analyses of gene expression profiling data revealed the crucial genes involved in neutrophil apoptosis and gave insight into the underlying mechanism. Given our data, it may be likely that novel opportunities for the treatment of neutropenia, and eventually improvement of prognosis of DLBCL patients, might emerge.

Longitudinal Study of Bone Height Change between Two Approaches for Sinus Floor Elevation.

Background and Objectives: The purpose of this study is to assess the long-term maintenance of each approach of sinus elevation, the crestal approach and lateral approach, by comparing the radiographic results of each technique. Materials and Methods: In total, 103 patients who had undergone an implant procedure with either the crestal approach or lateral approach method applied to their maxillary molar edentulous area were included. Using orthopantomographs, the radiographic changes were consistently evaluated over 3 years after the procedure (immediately after procedure and 1 year, 2 years and 3 years after implant placement) Results: The radiographic evaluation after 3 years of implantation with sinus elevation showed a significant amount of bone formation (8.07 mm for crestal approach and 12.00 mm for lateral approach method). The largest amount of grafted height loss occurred during the 1 year, but the resorption was minimal (0.98 mm for crestal approach and 0.95 mm for lateral approach method) over the entire 3 years. Conclusions: Although the lateral approach showed more bone growth, the amount of bone resorption was similar to that of the crestal approach. Both methods showed the highest amount of bone resorption in the first year, and the amount of change thereafter was insignificant. It is judged that both methods can be used according to the situation to help implant placement.

Reliable Reference Areas for Three-dimensional Smiling Facial Model Alignments: Posed Versus Natural Smile Expressions.

PURPOSE: This study aims to evaluate the reliability of various reference areas for digital alignment between three-dimensional (3D) resting and smiling facial models. MATERIALS AND METHODS: 3D posed and natural smiling faces of 33 adults were registered to the respective neutral faces, using six matching strategies with different reference matching surfaces: nose (N), nose + central forehead (NFc), nose + whole forehead (NFw), nose + chin (NC), nose + central forehead + chin (NFcC), and nose + whole forehead + chin (NFwC). The positional discrepancies of the registered images were measured at the left and right pupil centers. RESULTS: Two-way ANOVA and post hoc multiple pairwise t-test with Bonferroni correction (α = .05) were used to evaluate the measurements. As a result, the use of larger reference areas increases the trueness of image matching; whereas, there was no statistically significant difference between the matching strategies within the same smiling type. Meanwhile, the image registration of posed smiles resulted in fewer positional disparities than the natural smiles with significant differences observed for the registration using the NC and NFcC surface-based matching areas at the right pupil (P = .030 and .026, respectively). CONCLUSION: The findings of this study suggested that the reference surface areas and smiling types have some impacts on the accuracy of 3D smiling facial image alignments. Large and evenly distributed matching surfaces are recommended for posed smiles; whereas caution should be taken when using the chin area as a reference surface for matching natural smile facial images. Int J Prosthodont 2023. doi: 10.11607/ijp.8364.

Intra- and Interrater Agreement of Face Esthetic Analysis in 3D Face Images.

The use of three-dimensional (3D) facial scans for facial analysis is increasing in maxillofacial treatment. The aim of this study was to investigate the consistency of two-dimensional (2D) and 3D facial analyses performed by multiple raters. Six men and four women (25-36-year-old) participated in this study. The 2D images of the smiling and resting faces in the frontal and sagittal planes were obtained. The 3D facial and intraoral scans were merged to generate virtual 3D faces. Ten clinicians performed facial analyses by investigating 14 indices of 2D and 3D faces. Intra- and interrater agreements of the results of 2D and 3D facial analyses within and among the participants were evaluated. The intrarater agreement between the 2D and 3D facial analyses varied according to the indices. The highest and lowest agreements were found for the dental crowding index (0.94) and smile line curvature index (0.56) in the frontal plane, and Angle's classification (canine) index (0.98) and occlusal plane angle index (0.55) in the profile plane. In the frontal plane, the interrater agreements were generally higher for the 3D images than for the 2D images, while in the profile plane, the interrater agreements were high in the Angle's classification (canine) index however low in the other indices. Several occlusion-related indices were missing in the 2D images because the posterior teeth were not observed. Esthetic analysis results between 2D and 3D face images can differ according to the evaluation indices. The use of 3D faces is recommended over 2D images to increase the reliability of facial analyses, as it can fully assess both esthetic and occlusion-related indices.

Three-dimensional morphometric analysis of facial units in virtual smiling facial images with different smile expressions.

PURPOSE: Accuracy of image matching between resting and smiling facial models is affected by the stability of the reference surfaces. This study aimed to investigate the morphometric variations in subdivided facial units during resting, posed and spontaneous smiling. MATERIALS AND METHODS: The posed and spontaneous smiling faces of 33 adults were digitized and registered to the resting faces. The morphological changes of subdivided facial units at the forehead (upper and lower central, upper and lower lateral, and temple), nasal (dorsum, tip, lateral wall, and alar lobules), and chin (central and lateral) regions were assessed by measuring the 3D mesh deviations between the smiling and resting facial models. The one-way analysis of variance, Duncan post hoc tests, and Student's t-test were used to determine the differences among the groups (α = .05). RESULTS: The smallest morphometric changes were observed at the upper and central forehead and nasal dorsum; meanwhile, the largest deviation was found at the nasal alar lobules in both the posed and spontaneous smiles (P < .001). The spontaneous smile generally resulted in larger facial unit changes than the posed smile, and significant difference was observed at the alar lobules, central chin, and lateral chin units (P < .001). CONCLUSION: The upper and central forehead and nasal dorsum are reliable areas for image matching between resting and smiling 3D facial images. The central chin area can be considered an additional reference area for posed smiles; however, special cautions should be taken when selecting this area as references for spontaneous smiles.

Impact of marginal defects on the accuracy of automated finish line detection in tooth preparation.

AIM: The present study aimed to evaluate the accuracy of automated detection of preparation finish lines in teeth with defective margins. MATERIALS AND METHODS: An extracted first molar was prepared for a full veneer crown, and marginal defects were created and scanned (discontinuity of finish line: 0.5, 1.0, and 1.5 mm; additional line angle: connected, partially connected, and disconnected). Six virtual defect models were entered into CAD software and the preparation finish line was designated by 20 clinicians (CAD-experienced group: n = 10; CAD-inexperienced group: n = 10) using the automated finish line detection method. The accuracy of automatic detection was evaluated by calculating the 3D deviation of the registered finish line. The Kruskal-Wallis and Mann-Whitney U tests were used for between-group comparisons (α = 0.05). RESULTS: The deviation values of the registered finish lines were significantly different according to conditions with different amounts of finish line discontinuity (P < 0.001). There was no statistical difference in the deviation of the registered finish line between models with additional line angles around the margin. Moreover, no statistical difference was found in the results between CAD-experienced and CAD-inexperienced operators. CONCLUSIONS: The accuracy of automated finish line detection for tooth preparation can differ when the finish line is discontinuous. The presence of an additional line angle around the preparation margin and prior experience in dental CAD software do not affect the accuracy of automated finish line detection.

The Tumorigenic Role of Circular RNA-MicroRNA Axis in Cancer.

Circular RNAs (circRNAs) are a class of endogenous RNAs that control gene expression at the transcriptional and post-transcriptional levels. Recent studies have increasingly demonstrated that circRNAs act as novel diagnostic biomarkers and promising therapeutic targets for numerous cancer types by interacting with other non-coding RNAs such as microRNAs (miRNAs). The miRNAs are presented as crucial risk factors and regulatory elements in cancer by regulating the expression of their target genes. Some miRNAs are derived from transposable elements (MDTEs) that can transfer their location to another region of the genome. Genetic interactions between miRNAs and circular RNAs can form complex regulatory networks with various carcinogenic processes that play critical roles in tumorigenesis and cancer progression. This review focuses on the biological regulation of the correlative axis among circular RNAs, miRNAs, and their target genes in various cancer types and suggests the biological importance of MDTEs interacting with oncogenic or tumor-suppressive circRNAs in tumor progression.

Accuracy of Augmented Reality-Assisted Navigation in Dental Implant Surgery: Systematic Review and Meta-analysis.

BACKGROUND: The novel concept of immersive 3D augmented reality (AR) surgical navigation has recently been introduced in the medical field. This method allows surgeons to directly focus on the surgical objective without having to look at a separate monitor. In the dental field, the recently developed AR-assisted dental implant navigation system (AR navigation), which uses innovative image technology to directly visualize and track a presurgical plan over an actual surgical site, has attracted great interest. OBJECTIVE: This study is the first systematic review and meta-analysis study that aimed to assess the accuracy of dental implants placed by AR navigation and compare it with that of the widely used implant placement methods, including the freehand method (FH), template-based static guidance (TG), and conventional navigation (CN). METHODS: Individual search strategies were used in PubMed (MEDLINE), Scopus, ScienceDirect, Cochrane Library, and Google Scholar to search for articles published until March 21, 2022. This study was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and registered in the International Prospective Register of Systematic Reviews (PROSPERO) database. Peer-reviewed journal articles evaluating the positional deviations of dental implants placed using AR-assisted implant navigation systems were included. Cohen d statistical power analysis was used to investigate the effect size estimate and CIs of standardized mean differences (SMDs) between data sets. RESULTS: Among the 425 articles retrieved, 15 articles were considered eligible for narrative review, 8 articles were considered for single-arm meta-analysis, and 4 were included in a 2-arm meta-analysis. The mean lateral, global, depth, and angular deviations of the dental implant placed using AR navigation were 0.90 (95% CI 0.78-1.02) mm, 1.18 (95% CI 0.95-1.41) mm, 0.78 (95% CI 0.48-1.08) mm, and 3.96° (95% CI 3.45°-4.48°), respectively. The accuracy of AR navigation was significantly higher than that of the FH method (SMD=-1.01; 95% CI -1.47 to -0.55; P<.001) and CN method (SMD=-0.46; 95% CI -0.64 to -0.29; P<.001). However, the accuracies of the AR navigation and TG methods were similar (SMD=0.06; 95% CI -0.62 to 0.74; P=.73). CONCLUSIONS: The positional deviations of AR-navigated implant placements were within the safety zone, suggesting clinically acceptable accuracy of the AR navigation method. Moreover, the accuracy of AR implant navigation was comparable with that of the highly recommended dental implant-guided surgery method, TG, and superior to that of the conventional FH and CN methods. This review highlights the possibility of using AR navigation as an effective and accurate immersive surgical guide for dental implant placement.

Reliability of automatic finish line detection for tooth preparation in dental computer-aided software.

PURPOSE: This study aimed to investigate the accuracy of automatic tooth finish line registration compared to manual registration with regard to various finish line configurations and dental computer-aided design (CAD) software. METHODS: Finish line registrations were performed on 15 digital tooth models with different finish line configurations (edge roundness radius = 0 mm, 0.2 mm, and 0.4 mm; edge angle = 30°, 60°, 90°, 120°, and 150°) using automatic and manual methods for designing virtual copings (N = 150). The discrepancies between the registered finish line extracted from the copings and the actual finish line segmented from the digitized tooth model were measured. Three-way analysis of variance (ANOVA) and post-hoc analyses with Bonferroni correction (α = 0.05) were used to analyze the results. RESULTS: The finish line configurations, registration methods, and CAD software interacted with the accuracy of the registered finish line (p = 0.001). The automatic finish line registration method exhibited larger error values than the manual method, especially at high finish line edge roundness and obtuse edge angles for both EXOCAD and R2CAD software (p < 0.001). The difference in dental CAD software affected the registration accuracy in the automatic method (p < 0.001), but not in the manual method (p = 0.676). CONCLUSIONS: Finish line registration errors may occur when the automatic registration method is applied to the indistinct edge of tooth preparation. The accuracy of the automatic finish line registration could differ according to the CAD software program.

Dental diagnosis for inlay restoration using an intraoral optical coherence tomography system: A case report.

PATIENTS: The patient was a 32-year-old man who underwent amalgam restoration of the mandibular right second molar. An amalgam restoration fracture was diagnosed by intraoral optical coherence tomography (OCT), and pulp exposure was examined during cavity preparation. Subsequently, a definitive ceramic restoration was fabricated, and the marginal fit in the oral cavity was evaluated using the OCT system. DISCUSSION: The existing OCT system cannot acquire images inside the oral cavity because of the large probe size. However, the proposed intraoral OCT system can access the prostheses in the mandibular right second molar. Therefore, dental diagnosis for restoration treatment with dental prosthesis fracture, marginal gap, and pulp exposure after tooth preparation is possible using the proposed intraoral OCT system. CONCLUSIONS: The use of the intraoral OCT system improved dental diagnosis by allowing the dentist to confirm quantitative values through cross-sectional images, rather than that by determining a treatment plan after visual dental diagnosis.

Accuracy of digitally fabricated drilling guide to form screw-access channels in cement-retained implant prostheses: A randomized clinical trial.

STATEMENT OF PROBLEM: Accurate intraoral preparation of screw channels in cement-retained implant prostheses could be a treatment challenge for tilted or badly positioned implants. PURPOSE: The purpose of this randomized clinical trial was to evaluate screw channel accuracy for retrieving cement-retained implant prostheses by using a digitally fabricated drilling guide. MATERIAL AND METHODS: Twenty-four participants requiring removal of cement-retained implant prostheses were recruited and consecutively assigned to 1 of 2 groups. In the first group, drilling guides were fabricated by using an intraoral scan, computer-aided design (CAD), and 3D printing to facilitate screw channel preparation (guide group). In the second group, screw channel preparation was based on panoramic radiographs without a drilling guide (freehand group). Screw channel accuracy was evaluated with a 3D analysis and subsequently compared with the ideal shape of the screw channel for linear deviation at coronal and apical levels, angular deviation, surface loss deviation, and volume loss deviation. The ideal shape of the screw-access channel was based on the Ø2.2-mm cylinder image marked along the long axis of the implant. The Mann-Whitney U and Kruskal-Wallis tests were used for statistical analyses (α=.05). RESULTS: The drilling guide group showed higher dimensional accuracy than the freehand group for angular deviation (9.45 degrees versus 15.69 degrees; P=.014) and surface loss deviation (7.40 mm versus 9.53 mm; P=.001), especially when the implant was tilted more than 30 degrees. The deviation values of the screw channels were not significantly different according to implant tilt in either group (P>.05). CONCLUSIONS: Digitally fabricated drilling guides for intraoral preparation of screw channels in cement-retained implant prostheses can improve accuracy and provide a less-destructive screw channel.

ACCURACY OF REMOVABLE PARTIAL DENTURE METAL FRAMEWORKS FABRICATED BY COMPUTER-AIDED DESIGN/ COMPUTER-AIDED MANUFACTURING METHOD: A SYSTEMATIC REVIEW AND META-ANALYSIS.

OBJECTIVE: This systematic review and meta-analysis aimed to investigate the accuracy of removable partial denture (RPD) frameworks fabricated by computer-aided design/ computer-aided manufacturing (CAD/CAM) systems compared to frameworks produced by conventional casting methods. METHODS: A systematic literature search was conducted in electronic databases following the preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, using formulated Boolean operator for searching articles evaluating the fit accuracy of CAD/CAM-fabricated RPD metal frameworks. The agreement of data collection among the reviewers was confirmed using the Cohen kappa coefficient. The modified methodological index for non-randomized studies (MINORS) scale was used to assess the quality of the included studies. Heterogeneity among studies was evaluated, and meta-analyses with global and subgroup analyses were performed. RESULTS: A total of 208 articles were identified with 18 articles available for the narrative review and 7 studies available for meta-analysis on the 3D-printed frameworks for RPD (the overall Cohen kappa coefficient = 0.944). There was no article on the accuracy of RPD frameworks made by milling method. The meta-analysis revealed that the misfit of frameworks obtained with the CAD/CAM method was significantly higher than that of the conventional lost wax and casting method (SMD = 1.23 µm, 95% CI = 0.3610-2.0981 µm, z = 2.77, P = .0055). Regarding the CAD/CAM techniques used for fabricating RPD metal frameworks, the within subgroup analysis showed that the CAD/CAM-based indirect fabrication method produced frameworks with fit accuracy more similar to the conventional lost-wax and casting method (SMD = 1.15 µm, 95% CI = - 0.06136-2.9192 µm, z = 1.28, P < .01) than the CAD/CAM-based direct fabrication method (SMD = 1.35 µm, 95% CI = -0.2722-2.4381 µm, z = 2.45, P < .01), even though there was no statistical difference between the techniques (P = .8482). CONCLUSIONS: The fit accuracy of RPD metal frameworks fabricated by the CAD/CAM method was lower than that of frameworks fabricated by the conventional casting method, but it was within the clinically acceptable range in dimensional misfit. The indirect metal 3D printing technique based on pattern printing and subsequent casting produced frameworks with fit accuracy more similar to the conventional method than the direct fabrication technique.

Comparison of Wear of Interim Crowns in Accordance with the Build Angle of Digital Light Processing 3D Printing: A Preliminary In Vivo Study.

The aim of this study is to evaluate the wear volume of interim crowns fabricated using digital light processing 3D printing according to the printing angle. A total of five patients undergoing the placement of a single crown on the mandibular molar were included. Interim crowns were fabricated directly in the oral cavity using the conventional method. A digital light processing 3D printer was then used to fabricate crowns with build angles of 0, 45, and 90 degrees. Therefore, four fabricated interim crowns were randomly delivered to the patients, and each was used for one week. Before and after use, the intaglio surfaces of the interim crowns were scanned using a 3D scanner. The volume changes before and after use were measured, and changes in the height of the occlusal surface were evaluated using the root mean square value. Data normality was verified by statistical analysis, and the wear volume in each group was evaluated using a one-way analysis of variance and Tukey's honestly significant difference test (α = 0.05). Compared with the RMS values of the conventional method (11.88 ± 2.69 µm) and the 3D-printing method at 0 degrees (12.14 ± 2.38 µm), the RMS values were significantly high at 90 degrees (16.46 ± 2.39 µm) (p < 0.05). Likewise, there was a significant difference in the change in volume between the groups (p = 0.002), with a significantly higher volume change value at 90 degrees (1.74 ± 0.41 mm3) than in the conventional method (0.70 ± 0.15 mm3) (p < 0.05). A printing angle of 90 degrees is not recommended when interim crowns are fabricated using digital light processing 3D printing.

Integration of TE Induces Cancer Specific Alternative Splicing Events.

Alternative splicing of messenger RNA (mRNA) precursors contributes to genetic diversity by generating structurally and functionally distinct transcripts. In a disease state, alternative splicing promotes incidence and development of several cancer types through regulation of cancer-related biological processes. Transposable elements (TEs), having the genetic ability to jump to other regions of the genome, can bring about alternative splicing events in cancer. TEs can integrate into the genome, mostly in the intronic regions, and induce cancer-specific alternative splicing by adjusting various mechanisms, such as exonization, providing splicing donor/acceptor sites, alternative regulatory sequences or stop codons, and driving exon disruption or epigenetic regulation. Moreover, TEs can produce microRNAs (miRNAs) that control the proportion of transcripts by repressing translation or stimulating the degradation of transcripts at the post-transcriptional level. Notably, TE insertion creates a cancer-friendly environment by controlling the overall process of gene expression before and after transcription in cancer cells. This review emphasizes the correlative interaction between alternative splicing by TE integration and cancer-associated biological processes, suggesting a macroscopic mechanism controlling alternative splicing by TE insertion in cancer.

Z-DNA-Containing Long Terminal Repeats of Human Endogenous Retrovirus Families Provide Alternative Promoters for Human Functional Genes.

Transposable elements (TEs) account for approximately 45% of the human genome. TEs have proliferated randomly and integrated into functional genes during hominoid radiation. They appear as right-handed B-DNA double helices and slightly elongated left-handed Z-DNAs. Human endogenous retrovirus (HERV) families are widely distributed in human chromosomes at a ratio of 8%. They contain a 5'-long terminal repeat (LTR)-gag-pol-env-3'-LTR structure. LTRs contain the U3 enhancer and promoter region, transcribed R region, and U5 region. LTRs can influence host gene expression by acting as regulatory elements. In this review, we describe the alternative promoters derived from LTR elements that overlap Z-DNA by comparing Z-hunt and DeepZ data for human functional genes. We also present evidence showing the regulatory activity of LTR elements containing Z-DNA in GSDML. Taken together, the regulatory activity of LTR elements with Z-DNA allows us to understand gene function in relation to various human diseases.