Establishment of the mid-sagittal reference plane for three-dimensional assessment of facial asymmetry: a systematic review : Establishment of the mid-sagittal reference plane: a systematic review.

OBJECTIVE: To systematically review the literature for mid-sagittal plane establishment approaches to identify the most effective method for constructing the mid-sagittal plane for the evaluation of facial asymmetry. MATERIALS AND METHODS: Six electronic databases (PubMed, Medline (via Ovid), EMBASE (via Ovid), Cochrane Library, Web of Science, and Scopus) and grey literature were searched for the studies that computed the mid-sagittal reference plane three-dimensionally, using a combination of MeSH terms and keywords. The methodological quality and the level of evidence for the included studies were analyzed using QUADAS-2 and GRADE, respectively. RESULTS: The preliminary search yielded 6746 records, of which 42 articles that met the predefined inclusion criteria were included in the final analysis. All the included articles reported the construction of the mid-sagittal reference plane (MSP) using varied methods. The risk of bias and concerns regarding the applicability of the included studies were judged to be 'low'. The level of evidence was determined to be 'low' for the effectiveness of the technique and 'moderate' for the ease of clinical applicability. CONCLUSION: Despite methodological heterogeneity, this review substantiates the comparable efficacy of cephalometric and morphometric MSP construction methods. A fully automated morphometric MSP holds promise as a viable option for routine clinical use. Nevertheless, future prospective studies with an emphasis on the impact, accuracy, and clinical applicability of MSP construction techniques in cases of facial asymmetry are required. CLINICAL RELEVANCE: The present review will assist clinicians in selecting the most suitable method for MSP construction, leading to improved treatment planning and ultimately more favorable treatment outcomes.

Intracellular bacterial eradication using a novel peptide in vitro.

AIM: To determine the effect of a novel antimicrobial peptide (AMP; OP145) and cell-penetrating peptide (Octa-arginine/R8) conjugate on the killing of intracellular Enterococcus faecalis, compared to OP145 and an antibiotic combination recommended for regenerative endodontic procedures. METHODOLOGY: The biocompatible concentrations of OP145 and OP145-R8 were determined by assessing their cytotoxicity against human macrophages and red blood cells. Spatiotemporal internalization of the peptides into macrophages was investigated qualitatively and quantitatively by confocal laser scanning microscopy and flow cytometry respectively. Killing of extracellular and intracellular E. faecalis OG1RF by the peptides was determined by counting the colony-forming units (CFU). Intracellular antibacterial activity of the peptides was compared to a double antibiotic combination. Confocal microscopy was used to confirm the intracellular bacterial eradication. Significant differences between the different test groups were analysed using one-way analysis of variance. p < .05 was considered to be statistically significant. RESULTS: Peptides at a concentration of 7.5 µmol/L were chosen for subsequent experiments based on the results of the alamarBlue™ cell viability assay and haemolytic assay. OP145-R8 selectively internalized into lysosomal compartments and the cytosol of macrophages. Conjugation with R8 improved the internalization of OP145 into macrophages in a temporal manner (70.53% at 1 h to 77.13% at 2 h), while no temporal increase was observed for OP145 alone (60.53% at 1 h with no increase at 2 h). OP145-R8 demonstrated significantly greater extracellular and intracellular antibacterial activity compared to OP145 at all investigated time-points and concentrations (p < .05). OP145-R8 at 7.5 µmol/L eradicated intracellular E. faecalis after 2 h (3.5 log reduction compared to the control; p < .05), while the antibiotics could not reduce more than 0.5 log CFU compared to the control (p > .05). Confocal microscopy showed complete absence of E. faecalis within the OP145-R8 treated macrophages. CONCLUSIONS: The results of this study demonstrated that the conjugation of an AMP OP145 to a cell-penetrating peptide R8 eradicated extracellular and intracellular E. faecalis OG1RF without toxic effects on the host cells.

Comparison of the quality of life changes of patients receiving sagittal split ramus osteotomy or intraoral vertical subsigmoid osteotomy for mandibular prognathism.

OBJECTIVE: To investigate and compare the effect of two orthognathic procedures for mandibular setback, namely, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO), on oral health, mental- and physical health-related quality of life across time. MATERIALS AND METHODS: Patients with mandibular prognathism and planned for orthognathic surgery were recruited in this study. Patients were randomized into two groups (IVRO and SSRO groups). Quality of life (QoL) was assessed with the 14-item Short-Form Oral Health Impact Profile (OHIP-14) and the 36-item Short-Form Health Survey (SF-36) preoperatively (T0), postoperative 2 weeks (T1), 6 weeks (T2), 3 months (T3), 6 months (T4), 12 months (T5), and 24 months (T6). A comparison of OHIP-14 and SF-36 scores between two groups was conducted. RESULTS: Ninety-eight patients (49 SSRO group, 49 IVRO group) participated in this study. There was no significant difference in OHIP-14 scores between SSRO and IVRO throughout the treatment process. SSRO group had significant reduction of OHIP-14 score (i.e., improving oral health-related QoL) since postoperative 2 weeks, whereas IVRO group had significant reduction since postoperative 6 weeks. Starting from postoperative 3 months, the oral health-related QoL of both groups was already significantly better than the baseline level and continued to steadily improve afterwards. For SF-36, both groups had increased physical health summary score starting from postoperative 2 weeks, indicating an early and gradual recovery of physical health-related QoL. The mental health summary score of the SSRO group began to increase from postoperative 2 weeks, but that of the IVRO group only began to increase from postoperative 6 weeks. Patient age at the time of surgery was positively correlated with OHIP scores in the postoperative period. CONCLUSIONS: The study concludes that both SSRO and IVRO contributed to the improvement of QoL in the long term, but oral health- and mental health-related QoL of SSRO groups showed earlier improvement. CLINICAL RELEVANCE: Undergoing orthognathic surgery at early ages is advised, as older age of patients appeared to have worse QoL. TRIAL REGISTRATION: Clinical trial registration number: HKUCTR-1985. Date of Registration: 14 Apr 2015.

What are the surgical risks and 2-year stability of mandibular anterior subapical osteotomy in the treatment of dentoalveolar protrusion?

OBJECTIVE: To investigate the stability and complications of mandibular anterior subapical osteotomy (ASO) in the treatment of bimaxillary dentoalveolar protrusion by way of a retrospective study. MATERIALS AND METHODS: One hundred and twenty patients who received orthognathic surgery at a single center between 2008 and 2017 were included. Relapse was assessed by serial tracings of lateral cephalograms which were obtained pre-operatively (T1), within 6 weeks after surgery (T2) and at 2 years after surgery. The changes between T2 and T3 represented stability and were tested using the paired t test. The relationship between the extents of surgical repositioning (T2-T1) and relapse (T3-T2) was investigated using the Pearson correlation coefficient. The associations between the variables and the occurrence of relapse and complications identified the risk factors and were evaluated using the χ2 test or Fisher's exact test. When r > 0.80, clinical correlation was considered significant; and statistical significance was set at P < 0.05, while confidence interval was set at 95%. RESULTS: There was a mean uprighting of L1-MP by 12.7°. At 2 years after surgery, 96.7% of the patients experienced a mean relapse of L1-MP by 2.9°. The extent of surgical repositioning was only weakly correlated with that of relapse and no specific factor that increased the risk of relapse could be identified. The most frequent complications were blood loss requiring transfusion, wound dehiscence or infection, gingival recession, and periodontal bone loss, involving 25.8 to 43.3% of the patients. The remaining complications included tooth root damage, fixation hardware exposure or infection, lingual mucosal laceration, and tooth devitalization. There were no cases of avascular necrosis or nonunion. CONCLUSIONS: Although relapse occurred in most of the patients after 2 years, the actual extent was small (2.9°) which was not likely to be clinically significant. TRIAL REGISTRATION: HKUCTR-2964 CLINICAL RELEVANCE: Although ASO may be valuable in correcting mandibular dentoalveolar protrusion, the procedure brings with it risks and complications and should be reserved for severe deformities.

Factors affecting periodontal healing of the adjacent second molar after lower third molar surgery: a systematic review and meta-analysis.

OBJECTIVES: This systematic review and meta-analysis aim to evaluate the effect modifiers which may influence the periodontal healing of the adjacent second molar after lower third molar surgery. MATERIALS AND METHODS: Prospective studies including patients with third molars requiring removal, with at least 6 months follow-up were considered. Outcomes were periodontal probing depth (PPD) reduction, final PPD, clinical attachment level (CAL) change, final CAL, alveolar bone defect (ABD) reduction, and final ABD depth. Meta-regression was performed to identify factors. RESULTS: Fourteen studies were included in the quantitative synthesis. At 6 months, the PPD reduction was 1.06 mm (95% CI, 0.72 to 1.39 mm) and the remaining PPD was 3.81 mm (95% CI, 3.00 to 4.62 mm). Baseline PPD was strongly correlated with the remaining PPD at 6 months (p < 0.001, adjusted R2 = 70.05%). CONCLUSIONS: Lower third molar surgery results in a modest reduction in PPD, CAL, and ABD; however, periodontal defects still remain at 6 months and beyond. Baseline PPD is strongly correlated with final PPD. While age is not shown to have effect on most of the periodontal parameters, a larger baseline PPD is more likely to manifest with increasing age and third molar surgery should be done before severe periodontitis occurs to avoid persistent periodontal defects. CLINICAL RELEVANCE: This study shows that lower third molar surgery results in modest improvement in periodontal parameters on adjacent second molars and identified factors such as baseline PPD which may affect the healing, which may guide the pre-, peri-, and post-operative management of lower third molar surgery.

Accuracy and safety of in-house surgeon-designed three-dimensional-printed patient-specific implants for wafer-less Le Fort I osteotomy.

OBJECTIVES: The design and fabrication of three-dimensional (3D)-printed patient-specific implants (PSIs) for orthognathic surgery are customarily outsourced to commercial companies. We propose a protocol of designing PSIs and surgical guides by orthognathic surgeons-in-charge instead for wafer-less Le Fort I osteotomy. The aim of this prospective study was to evaluate the accuracy and post-operative complications of PSIs that are designed in-house for Le Fort I osteotomy. MATERIALS AND METHODS: The post-operative cone beam computer tomography (CBCT) model of the maxilla was superimposed to the virtual surgical planning to compare the discrepancies of pre-determined landmarks, lines, and principal axes between the two models. Twenty-five patients (12 males, 13 females) were included. RESULTS: The median linear deviations of the post-operative maxilla of the x, y, and z axes were 0.74 mm, 0.75 mm, and 0.72 mm, respectively. The deviations in the principal axes for pitch, yaw, and roll were 1.40°, 0.90°, and 0.60°, respectively. There were no post-operative complications related to the PSIs in the follow-up period. CONCLUSIONS: The 3D-printed PSIs designed in-house for wafer-less Le Fort I osteotomy are accurate and safe. CLINICAL RELEVANCE: Its clinical outcomes and accuracy are comparable to commercial PSIs for orthognathic surgery. TRIAL REGISTRATION: Clinical trial registration number: HKUCTR-2113. Date of registration: 29 July 2016.

Three-dimensional assessment of facial asymmetry in class III subjects, part 2: evaluating asymmetry index and asymmetry scores.

OBJECTIVES: To evaluate the outcomes of corrective surgical treatment for craniofacial asymmetry using four different methods with the aim of developing the best technique for craniofacial asymmetry assessment. MATERIALS AND METHODS: CBCT images of twenty-one class III subjects with surgically corrected craniofacial asymmetry and twenty-one matched controls were analyzed. Twenty-seven hard tissue landmarks were used to quantify asymmetry using the following methodologies: the asymmetry index (AI), asymmetry scores based on the clinically derived midline (CM), Procrustes analysis (PA), and modified Procrustes analysis (MPA). RESULTS: Modified Procrustes analysis successfully identified pre-operative asymmetry and revealed severe asymmetry at the mandibular regions compared to controls, which was comparable to the asymmetry index and clinically derived midline methods, while Procrustes analysis masked the asymmetric characteristics. Likewise, when comparing the post-surgical outcomes, modified Procrustes analysis not only efficiently determined the changes evidencing decrease in facial asymmetry but also revealed significant residual asymmetry in the mandible, which was congruent with the asymmetry index and clinically derived midline methods but contradictory to the results shown by Procrustes analysis. CONCLUSIONS: In terms of quantifying cranio-facial asymmetry, modified Procrustes analysis has evidenced to produce promising results that were comparable to the asymmetry index and the clinically derived midline, making it a more viable option for craniofacial asymmetry assessment. CLINICAL RELEVANCE: Modified Procrustes analysis is proficient in evaluating cranio-facial asymmetry with more valid clinical representation and has potential applications in assessing asymmetry in a wide spectrum of patients, including syndromic patients.

Pre-Epiglottic Baton Plate in the Management of Upper Airway Obstruction in an Infant with Femoral Facial Syndrome: A Case Report.

Femoral facial syndrome (FFS) is a rare condition which may present with hypoplasia or aplasia of the femora and unusual facies characterized by long philtrum, thin upper lip and micrognathia. We present the case of a ten-month old infant with FFS who had retroglossal obstruction and who was treated with a pre-epiglottic baton plate. The pre-epiglottic baton plate can be a simple, non-invasive and effective tool for the clinical management of syndromic patients with mild-to-moderate upper airway obstruction due to micrognathia.

Small molecule based anti-virulence approaches against Candida albicans infections.

Fungi are considered "silent killers" due to the difficulty of, and delays in diagnosis of infections and lack of effective antifungals. This challenge is compounded by the fact that being eukaryotes, fungi share several similarities with human cellular targets, creating obstacles to drug discovery. Candida albicans, a ubiquitous microbe in the human body is well-known for its role as an opportunistic pathogen in immunosuppressed people. Significantly, C. albicans is resistant to all the three classes of antifungals that are currently clinically available. Over the past few years, a paradigm shift has been recommended in the management of C. albicans infections, wherein anti-virulence strategies are considered an alternative to the discovery of new antimycotics. Small molecules, with a molecular weight <900 Daltons, can easily permeate the cell membrane and modulate the signal transduction pathways to elicit desired virulence inhibitory actions against pathogens. This review dissects in-depth, the discoveries that have been made with small-molecule anti-virulence approaches to tackle C. albicans infections.

Patient-specific estimation of the bone graft volume needed for maxillary sinus floor elevation: a radiographic study using cone-beam computed tomography.

OBJECTIVE: To develop prediction models for estimating the bone-graft volume needed for sinus floor elevation (SFE) based on the augmentation site, elevation height, and sinus width using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: CBCT scans with a medium-to-large field-of-view with bilateral maxillary sinuses partially/entirely visible, acquired from February 2016 to October 2020, were initially screened. Ten defined regions, above the maxillary first (MM1) and second molar (MM2) sites, in the sinuses of the included CBCTs were semi-automatically segmented, and the volumes of the regions were automatically measured using the ITK-SNAP program. The sinus widths at the height ranging between 8 and 16 mm from the sinus floor were measured at the MM1 to MM2 sites, respectively. Multiple linear regression analyses were performed to establish prediction models for estimating the bone graft volume needed for SFE at the MM1 and/or MM2 sites with the sinus width and elevation height as predictors. RESULTS: A total of 133 scans (224 sinuses) were included. Three developed prediction models, composed of the sinus width and elevation height, explained 89-91% of the variation in the bone graft volumes estimated for SFE at the MM1, MM2, and MM1-MM2 sites. The mean absolute deviations and absolute percentage deviations between the measured and predicted volumes ranged from 0.12 to 0.28cm3 and from 9.78 to 10.62%, respectively. CONCLUSION: The proposed prediction models may enable more patient-specific estimation of the bone graft volume needed for SFE. CLINICAL RELEVANCE: The proposed prediction models could facilitate the preparation of an adequate amount of bone graft material and patient-clinician communication about the cost of bone graft material.

Linear and angular measurement using cone-beam computed tomography to enhance safety in Le Fort I osteotomy with tuberosity cut.

OBJECTIVE: The study aimed to evaluate surgical angles for tuberosity cut and linear and angular measurements for all horizontal cuts in Le Fort I osteotomy using cone-beam computed tomography (CBCT). MATERIALS AND METHODS: This study included 189 CBCT scans to assess the surgical angles on 3 different sites distal to maxillary second molars relative to the midsagittal plane (MSP) and the buccal cortical plane (BCP) in relation to the descending palatine foramen for tuberosity cut. The linear and angular measurements for all horizontal cuts in Le Fort I osteotomy were also evaluated. RESULTS: The mean surgical angles for tuberosity cut varied from 58.90 to 95.28° and 74.85 to 100.93° according to the MSP and the BCP, respectively. For the horizontal cuts, mean lengths (angles) for posterior buccal and lateral nasal wall osteotomies were 27.44 mm (13.62°) and 33.20 mm (9.60°), respectively, and a mean length of 47.12 mm was measured for nasal septum osteotomy. Additionally, the presence of impacted third molar resulted in significantly higher mean surgical angles than those with fully erupted or without third molars (p < 0.01). CONCLUSIONS: Overall, angles running through the buccal midpoint of the third molars relative to the MSP (76.56°) or the BCP (92.31°) might be the most appropriate in clinical practice. Furthermore, some caution seems warranted when performing tuberosity cuts with the impacted third molars. CLINICAL RELEVANCE: To avoid potential damage to the descending palatine artery for tuberosity cut in Le Fort I osteotomy.

Assessment of the prevalence and length of the anterior and caudal loops of the mental nerve as anatomical variants of exiting the mandible at the mental foramen using cone-beam computed tomography: a systematic review and meta-analysis.

OBJECTIVES: This systematic review aimed to identify the studies that performed cone-beam computed tomography analysis of the prevalence and length of the anterior loop (AL) and caudal loop (CL) of the mental nerve. MATERIALS AND METHODS: An electronic database search was performed across PubMed, EMBASE, Web of Science, Scopus, the Cochrane library, and Google Scholar. Original studies reporting the frequency and length of the AL and CL were selected. Qualitative synthesis and meta-analysis were then conducted to assess the prevalence and length of the AL and CL and their associations with age, gender, sides, and dentition status. RESULTS: A total of 21 studies were included in this review. The pooled prevalence of the AL (95% confidence interval) of the mental nerve at the patient and side level was 51% (31-71%) and 53% (37-69%) while the mean anterior loop length was 2.08 (1.46-2.70) mm. The pooled prevalence of the CL and mean caudal loop length were 100% and 4.73 (3.44-6.01) mm. No significant associations were found between the prevalence and length of the AL and CL and age, gender, sides, and dentition status. CONCLUSIONS: Overall, the pooled prevalence and mean length of AL of the mental nerve varied among different populations while CL seems to be a constant anatomical landmark with a longer CL than AL. CLINICAL RELEVANCE: Surgeons performing inter-foraminal oral surgeries like dental implant placement and genioplasty should be aware of the possible distance of the AL and CL to avoid iatrogenic mental nerve injury.

Potential and impact of artificial intelligence algorithms in dento-maxillofacial radiology.

OBJECTIVES: Novel artificial intelligence (AI) learning algorithms in dento-maxillofacial radiology (DMFR) are continuously being developed and improved using advanced convolutional neural networks. This review provides an overview of the potential and impact of AI algorithms in DMFR. MATERIALS AND METHODS: A narrative review was conducted on the literature on AI algorithms in DMFR. RESULTS: In the field of DMFR, AI algorithms were mainly proposed for (1) automated detection of dental caries, periapical pathologies, root fracture, periodontal/peri-implant bone loss, and maxillofacial cysts/tumors; (2) classification of mandibular third molars, skeletal malocclusion, and dental implant systems; (3) localization of cephalometric landmarks; and (4) improvement of image quality. Data insufficiency, overfitting, and the lack of interpretability are the main issues in the development and use of image-based AI algorithms. Several strategies have been suggested to address these issues, such as data augmentation, transfer learning, semi-supervised training, few-shot learning, and gradient-weighted class activation mapping. CONCLUSIONS: Further integration of relevant AI algorithms into one fully automatic end-to-end intelligent system for possible multi-disciplinary applications is very likely to be a field of increased interest in the future. CLINICAL RELEVANCE: This review provides dental practitioners and researchers with a comprehensive understanding of the current development, performance, issues, and prospects of image-based AI algorithms in DMFR.

Automatic detection and segmentation of morphological changes of the maxillary sinus mucosa on cone-beam computed tomography images using a three-dimensional convolutional neural network.

OBJECTIVES: To propose and evaluate a convolutional neural network (CNN) algorithm for automatic detection and segmentation of mucosal thickening (MT) and mucosal retention cysts (MRCs) in the maxillary sinus on low-dose and full-dose cone-beam computed tomography (CBCT). MATERIALS AND METHODS: A total of 890 maxillary sinuses on 445 CBCT scans were analyzed. The air space, MT, and MRCs in each sinus were manually segmented. Low-dose CBCTs were divided into training, training-monitoring, and testing datasets at a 7:1:2 ratio. Full-dose CBCTs were used as a testing dataset. A three-step CNN algorithm built based on V-Net and support vector regression was trained on low-dose CBCTs and tested on the low-dose and full-dose datasets. Performance for detection of MT and MRCs using area under the curves (AUCs) and for segmentation using Dice similarity coefficient (DSC) was evaluated. RESULTS: For the detection of MT and MRCs, the algorithm achieved AUCs of 0.91 and 0.84 on low-dose scans and of 0.89 and 0.93 on full-dose scans, respectively. The median DSCs for segmenting the air space, MT, and MRCs were 0.972, 0.729, and 0.678 on low-dose scans and 0.968, 0.663, and 0.787 on full-dose scans, respectively. There were no significant differences in the algorithm performance between low-dose and full-dose CBCTs. CONCLUSIONS: The proposed CNN algorithm has the potential to accurately detect and segment MT and MRCs in maxillary sinus on CBCT scans with low-dose and full-dose protocols. CLINICAL RELEVANCE: An implementation of this artificial intelligence application in daily practice as an automated diagnostic and reporting system seems possible.

Three-dimensional assessment of facial asymmetry in Class III subjects. Part 1: a retrospective study evaluating postsurgical outcomes.

OBJECTIVE: The present study aimed to determine the site and severity of maxillomandibular asymmetry before and after orthognathic surgery in asymmetric patients. MATERIALS AND METHODS: Presurgery and postsurgery cone beam computed tomography (CBCT) data of 21 facial asymmetry patients (7 males and 14 females, mean age: 23.0 ± 3.36 years) with soft tissue chin deviation ≥ 3 mm who had undergone bimaxillary surgery were evaluated. Seven midline and twenty bilateral hard tissue landmarks were identified for the evaluation of facial asymmetry and outcomes were assessed against age- and gender-matched control subjects. RESULTS: In the asymmetry group, bilateral landmarks exhibited significant deviation in the mandible and midface regions. Before surgery, asymmetry was more severe at the mandibular midline and sites close to it, in the asymmetry group. Bimaxillary surgery proved to be highly effective, with a significant correction of the menton to a clinically normal value (2.90 mm, p < 0.001). After surgery, significant residual asymmetry was observed at the mental foramen (p = 0.001) in the R-L direction. Moreover, significant asymmetry persisted at the sigmoid notch (p = 0.001) in the S-I direction. CONCLUSIONS: Mandibular midline landmarks and chin peripheral regions contribute significantly to overall facial asymmetry characteristics. Despite significant correction after bimaxillary surgery, asymmetry persisted at several sites, thereby requiring secondary correction. Comprehensive 3D presurgical planning is central for asymmetry correction in a single surgery. CLINICAL RELEVANCE: The present study specifies the location of residual asymmetry sites and advocates the correction of those sites during initial surgery.

Accuracy of self-designed 3D-printed patient-specific surgical guides and fixation plates for advancement genioplasty.

AIM: A prospective study was conducted to evaluate the accuracy and complications of 3D-printed patient-specific surgical guides and plates that were designed and finished in-house. MATERIALS AND METHODS: Eighteen patients who required advancement genioplasty, with or without concomitant orthognathic surgery, were enrolled in the study. Virtual surgical movements were simulated using the patient's CBCT scans, and the computer-aided designing of patient-specific surgical guides and fixation plates was performed in the authors' department. CBCT scans were taken at 1-month postoperatively, and stereolithographic models of the preoperative virtual plan and the postoperative CBCT scan were registered. Part comparisons were performed to assess the accuracy of the movements. The median, minimum, and maximum differences were measured. Two landmarks, the Menton (Me) and Pogonion (Pog), were also used to compare the differences locally. RESULTS: The median deviation for the 18 cases was 0.19 mm. The median deviation at the Me and Pog were 0.67 and 0.41 mm, respectively. There was no significant correlation between the surgical movement of < 7 mm advancement and the transfer accuracy (P = 0.77). No adverse events or complications were reported within the postoperative 6-month period. CONCLUSION: The protocol of self-designed 3D-printed patient-specific surgical guides and plates provided an accurate method to transfer the virtual surgical plan to the operating theater. (Int J Comput Dent 2022;25(4):369-0; doi: 10.3290/j.ijcd.b2599791).

Identification and integrated analysis of differentially expressed long non-coding RNAs associated with periodontitis in humans.

BACKGROUND AND OBJECTIVE: Long non-coding RNAs (lncRNAs) can act as competing endogenous RNAs (ceRNAs) to compete for micro-RNAs (miRNAs) in regulation of downstream genes, various biological functions and diseases. Yet, the expression and regulation of lncRNAs in periodontitis are not fully understood. The objective of the study was to identify potential genes (lncRNA, messenger RNA [mRNA] and miRNA) involved in periodontitis, construct lncRNA-miRNA-mRNA ceRNA networks, explore gene functions and validate gene expressions. MATERIAL AND METHODS: The data sets for the lncRNA, mRNA and miRNA expression profiles in gingival samples from periodontally healthy subjects and chronic periodontitis patients were obtained from the Gene Expression Omnibus. The differentially expressed lncRNAs (DElncRNAs), mRNAs (DEmRNAs) and miRNAs (DEmiRNAs) were identified, and ceRNA networks were then constructed. The expression of DElncRNAs and DEmRNAs was examined by quantitative real-time polymerase chain reaction (qPCR). Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for exploring the potential functions and biological pathways. RESULTS: The GSE80715 and GSE54710 data sets were retrieved. Subsequently, 26 DElncRNAs, 436 DEmRNAs and 12 DEmiRNAs were identified (|fold change| ≥2, adjusted p < 0.05). Further bioinformatics analysis contributed to establishment of the ceRNA networks, which consisted of 10 DElncRNAs, 11 DEmiRNAs and 83 DEmRNAs. Notably, the qPCR results showed a marked decrease in the expression of lncRNA H19 and two mRNAs (NOS1 and MAPT) which further supported the identified ceRNA network. The GO results revealed that the up-regulated mRNAs were significantly enriched in inflammatory processes, whilst the down-regulated mRNAs were enriched in cellular potentials. CONCLUSION: Non-coding RNAs are critically involved in the regulatory mechanisms in the pathogenesis of periodontitis. Further study is warranted to investigate the specific underlying genetic traits and networks.

Facial protection in the era of COVID-19: A narrative review.

We live in extraordinary times, where COVID-19 pandemic has brought the whole world to a screeching halt. Tensions and contradictions that surround the pandemic ridden world include the availability, and the lack thereof, various facial protection measures to mitigate the viral spread. Here, we comprehensively explore the different types of facial protection measures, including masks, needed both for the public and the healthcare workers (HCW). We discuss the anatomy, the critical issues of disinfection and reusability of masks, the alternative equipment available for the protection of the facial region from airborne diseases, such as face shields and powered air-purifying respirators (PAPR), and the skin health impact of prolonged wearing of facial protection by HCW. Clearly, facial protection, either in the form of masks or alternates, appears to have mitigated the pandemic as seen from the minimal COVID-19 spread in countries where public mask wearing is strictly enforced. On the contrary, the healthcare systems, that appear to have been unprepared for emergencies of this nature, should be appropriately geared to handle the imbalance of supply and demand of personal protective equipment including face masks. These are two crucial lessons we can learn from this tragic experience.

Mandibular asymmetry as a possible etiopathologic factor in temporomandibular disorder: a prospective cohort of 134 patients.

OBJECTIVES: The present study aimed to investigate mandibular asymmetry as a possible etiopathologic factor in temporomandibular disorder (TMD). MATERIALS AND METHODS: A prospective cross-sectional study of patients with dentofacial deformities seeking corrective orthognathic surgery was conducted. The pre-operative prevalence of TMD in patients with mandibular asymmetry and other dentofacial deformities was assessed using the Diagnostic Criteria for TMD (DC/TMD) Axis I protocol. RESULTS: A total of 134 patients were recruited - 82 with mandibular asymmetry and 52 without. There was a significantly higher prevalence of TMD in those with mandibular asymmetry (67.1%; 95% CI 59 to 75%) compared to those without (40.4%; 95% CI 32 to 49%, p = 0.002). The overall pre-operative prevalence of TMD in this population of patients was 56.7% (95% CI 48 to 65%). Pain disorder only was present in 9.7%, TMJ disorder only in 29.9%, and both pain and TMJ disorders in 17.2%. The most prevalent type of TMD is disc displacement with reduction (77.6%), followed by myalgia (35.5%) and arthralgia (21.1%). CONCLUSION: The prevalence of TMD in those with mandibular asymmetry was significantly higher than those without, suggesting that mandibular asymmetry could be a possible etiopathologic factor in TMD. CLINICAL RELEVANCE: The significantly higher prevalence of temporomandibular disorder in those with mandibular asymmetry suggests that we need to be especially cognizant of this condition in our pre-operative, surgical, and post-operative management of this group of orthognathic patients.

Cone beam computed tomography artefacts around dental implants with different materials influencing the detection of peri-implant bone defects.

OBJECTIVES: To investigate the diagnostic accuracy of cone beam computed tomography (CBCT) for the diagnosis of peri-implant bone defects of titanium (Ti), zirconium dioxide (ZrO2 ) or titanium-zirconium (Ti-Zr) alloy implants. MATERIALS AND METHODS: Ti, Ti-Zr or ZrO2 implants with two diameters (3.3 mm, 4.1 mm) and one length (10 mm) were inserted in the angle of the mandible of six fresh defrosted pig jaws. Out of the 12 implants inserted, 6 served in the test group with standardized buccal peri-implant bone defects, whereas 6 served as control without bone defects. CBCTs were performed with three acquisition protocols (standard, high and low dose) using two devices. Four observers analysed CBCTs as follows: (a) presence of a peri-implant defect; (b) presence of peri-implant artefacts and impact on defect diagnosis; and (c) linear measurements of buccal peri-implant defect including height and width (in mm). RESULTS: CBCT device, CBCT settings, implant material, implant diameter and observer background did not significantly influence diagnostic accuracy. The sensitivity and specificity values were high for defect detection. ZrO2 led to a lower than average diagnostic accuracy (0.781). The linear measurements of peri-implant defect were underestimated by <1 mm on average. The subjective impact of artefacts on defect diagnosis was significantly affected by implant material and observer background. CONCLUSIONS: CBCT showed high diagnostic accuracy for peri-implant bone defect detection regardless of the device, imaging setting or implant material used. If CBCT is indicated to assess peri-implant bone disease, low dose protocols could be a promising imaging modality.