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.

Detection of myofascial trigger points in the masseter muscle using ultrasonography in patients with myogenous temporomandibular disorder.

OBJECTIVE: We aimed to investigate the diagnostic efficacy of ultrasonography (US) using gray scale B-mode and ultrasound elastography (UE) in detecting myofascial trigger points (MTPs) in the masseter muscles of patients with myogenous temporomandibular disorder (TMD). STUDY DESIGN: A diagnostic cross-sectional study of patients with MTPs in the masseter muscles using US was conducted. The diagnostic results from the US examinations were compared with the clinical examination reference standard to determine the diagnostic efficacy of US. MTPs were detected as band-like hypoechoic localized areas with reduced vibration amplitude (stiffer) under US B-mode and UE imaging. RESULTS: In total, 116 sites from 29 patients (3 males, 26 females) with a mean age of 39.4 years were examined. US exhibited sensitivity of .946 (95% CI: .851-.989) and specificity of .900 (95% CI: .795-.962) in detecting MTPs when compared to the clinical examination. Diagnostic accuracy ranged from .902 to .950 when assuming 3 levels of myogenous TMD prevalence. CONCLUSION: US B-mode and UE imaging exhibited diagnostic accuracy comparable to the standard clinical examination carried out by a trained specialist. It can be a reliable technique in the detection and localization of MTPs for the diagnosis of myogenous TMD and localization of MTPs for therapeutic purposes.

Neuronavigation-guided Percutaneous Rhizotomies to Trigeminal Neuralgia: A Systematic Review.

OBJECTIVE: Neuronavigation improves intraoperative visualization of the cranial structures, which is valuable in percutaneous surgical treatments for patients with trigeminal neuralgia (TN) who are refractory to pharmacotherapy or reluctant to receive open surgery. The objective of this review was to evaluate the available neuronavigation-guided percutaneous surgical treatment modalities with cannulation of foramen ovale to TN, and their relative benefits and limitations. METHODS: This review was conducted based on the PRISMA statement. An initial search was performed on electronic databases, followed by manual and reference searches. Study and patient characteristics, rhizotomy procedure and neuronavigation details, and treatment outcomes (initial pain relief and pain recurrence within 2 y, success rate of forman ovale cannulation, and complications) were evaluated. The risk of bias was assessed with a quality assessment based on the ROBINS-I tools. RESULTS: Ten studies (491 operations, 403 participants) were analyzed. Three percutaneous trigeminal rhizotomy modalities identified were radiofrequency thermocoagulation rhizotomy (RFTR), percutaneous balloon compression, and glycerol rhizotomy. Intraoperative computed tomography and magnetic resonance imaging fusion-based RFTR had the highest initial pain relief rate of 97.0%. The success rate of foramen ovale cannulation ranged from 92.3% to 100% under neuronavigation. Facial hypoesthesia and masticatory muscle weakness were the most reported complications. DISCUSSION: Neuronavigation-guided percutaneous trigeminal rhizotomies showed possible superior pain relief outcomes to that of conventional rhizotomies in TN, with the benefits of radiation reduction and lower complication development rates. The limitations of neuronavigation remain its high cost and limited availability. Higher-quality prospective studies and randomized clinical trials of neuronavigation-guided percutaneous trigeminal rhizotomy were lacking.

Third Molar Coronectomy vs Total Removal in Second Molar Periodontal Healing.

OBJECTIVES: The objective of this randomised controlled trial was to compare the periodontal healing at the distal of the adjacent second molar after coronectomy or surgical removal and the surgical morbidities of the 2 techniques. METHODS: This is a pilot study of a split-mouth randomised clinical trial comparing the periodontal healing of the adjacent second molar after coronectomy or total removal of lower third molars, which was registered with the University of Hong Kong Clinical Trial Centre as HKUCTR-2948 on 21 February 2020. Cone beam computed tomography (CBCT) scans were taken preoperatively and at 6 months postoperatively. Changes in the bone level from the cemento-enamel junction, periodontal probing depth (PPD), and clinical attachment level (CAL) at the distal of the adjacent second molar were compared. Surgical morbidities in terms of pain, infection, neurologic deficit, root exposure, and need for second surgery for removal were assessed. RESULTS: Forty patients (22 male, 18 female) with mean age of 26.7 years were evaluated at 6 months postoperatively. Both coronectomy and total removal groups demonstrated statistically significant reduction in PPD and CAL. There was an alveolar bone gain of 1.28 ± 0.88 mm in the coronectomy group and 1.13 ± 0.73mm in the control group, which was statistically significant (P < .001 for both groups). CONCLUSIONS: Early findings show the periodontal healing at the adjacent second molar of coronectomy was as good as that of total removal of lower third molar. There were no differences in terms of surgical morbidities between both groups.

Can smartphones be used for routine dental clinical application? A validation study for using smartphone-generated 3D facial images.

OBJECTIVES: To compare the accuracy of smartphone-generated three-dimensional (3D) facial images to that of direct anthropometry (DA) and 3dMD with the aim of assessing the validity and reliability of smartphone-generated 3D facial images for routine clinical applications. MATERIALS AND METHODS: Twenty-five anthropometric soft-tissue facial landmarks were labelled manually on 22 orthognathic surgery patients (11 males and 11 females; mean age 26.2 ± 5.3 years). For each labelled face, two imaging operations were performed using two different surface imaging systems: 3dMDface and Bellus3D FaceApp. Next, 42 inter-landmark facial measurements amongst the identified facial landmarks were measured directly on each labelled face and also digitally on 3D facial images. The measurements obtained from smartphone-generated 3D facial images (SGI) were statistically compared with those from DA and 3dMD. RESULTS: SGI had slightly higher measurement values than DA and 3dMD, but there was no statistically significant difference between the mean values of inter-landmark measures across the three methods. Clinically acceptable differences (≤3 mm or ≤5°) were observed for 67 % and 74 % of measurements with good agreement between DA and SGI, and 3dMD and SGI, respectively. An overall small systematic bias of ± 0.2 mm was observed between the three methods. Furthermore, the mean absolute difference between DA and SGI methods was highest for linear (1.41 ± 0.33 mm) as well as angular measurements (3.07 ± 0.73°). CONCLUSIONS: SGI demonstrated fair trueness compared to DA and 3dMD. The central region and flat areas of the face in SGI are more accurate. Despite this, SGI have limited clinical application, and the panfacial accuracy of the SGI would be more desirable from a clinical application standpoint. CLINICAL SIGNIFICANCE: The usage of SGI in clinical practice for region-specific macro-proportional facial assessment involving central and flat regions of the face or for patient education purposes, which does not require accuracy within 3 mm and 5° can be considered.

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.

Self-designed three-dimensional printed skeletal anchorage titanium device for orthopaedic traction in a growing Class III patient.

Maxillary retrusion in a growing skeletal class III patient can be treated with growth modification by facemask therapy with skeletal anchorage. A 12-year-old boy presented with Skeletal Class III relationship, retrognathic maxilla and paranasal deficiency. Cone beam computer tomography (CBCT) was taken for the design of the customized skeletal anchorage device with a 3D planning computer software. Two pairs of skeletal anchorage surgical guides and plates were designed with the correct vector and location, and to avoid tooth roots in the fixation. The plates were printed with titanium and fixed onto the patient for the facemask therapy. CAD-CAM technology allows customization and precise execution of the skeletal anchorage for the facemask therapy. Self-designed 3D printed skeletal anchorage device, with the advantages of increased rigidity, ease of placement and accuracy of force application, can be a valid alternative to stock titanium plates.

Application of Cone Beam Computed Tomography in Risk Assessment of Lower Third Molar Surgery.

Risks of lower third molar surgery like the inferior alveolar nerve injury may result in permanent consequences. Risk assessment is important prior to the surgery and forms part of the informed consent process. Traditionally, plain radiographs like orthopantomogram have been used routinely for this purpose. Cone beam computed tomography (CBCT) has offered more information from the 3D images in the lower third molar surgery assessment. The proximity of the tooth root to the inferior alveolar canal, which harbours the inferior alveolar nerve, can be clearly identified on CBCT. It also allows the assessment of potential root resorption of the adjacent second molar as well as the bone loss at its distal aspect as a consequence of the third molar. This review summarized the application of CBCT in the risk assessment of lower third molar surgery and discussed how it could aid in the decision-making of high-risk cases to improve safety and treatment outcomes.

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.

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.

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.

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.

Patient-Specific Implants in Orthognathic Surgery.

Virtual surgical planning and three-dimensional (3D) printing have broadened the horizons of oral and maxillofacial surgery, including orthognathic surgery. 3D-printed personalized surgical guide and patient-specific implant (PSI) not only serve to guide accurate osteotomies and as a good fitting of osteosynthesis plate, but more importantly define a revolutionary waferless approach concept that is totally different from the conventional wafer-guided jaw fixation technique. This review discusses the limitations of the conventional orthognathic approach, and how PSI may overcome these limitations, improve accuracy, and bring additional benefits in the execution of orthognathic surgery.

The Use of CBCT in Evaluating the Health and Pathology of the Maxillary Sinus.

The use of cone-beam computed tomography (CBCT) has been increasing in dental practice. This narrative review summarized the relevance and utilizations of CBCT to visualize anatomical structures of the maxillary sinus and common pathologies found in the maxillary sinus. The detection/visualization rate, the location and the morphometric characteristics were described. For sinus anatomy, the reviewed features included the posterior superior alveolar artery, sinus pneumatization, sinus hypoplasia, sinus septa, and primary and accessory sinus ostia. For pathology, the following items were reviewed: membrane thickening associated with periapical lesions/periodontal lesions, mucous retention cyst, and antrolith. The visualization and assessment of the maxillary sinus is very important prior to procedures that take place in close proximity with the sinus floor, such as tooth extraction, implant insertion, and sinus floor elevation. Some sinus pathologies may be associated with odontogenic lesions, such as periapical diseases and periodontal bone loss.

The Global Impact of COVID-19 on Craniomaxillofacial Surgeons: A Follow-Up Survey After One Year.

Study Design: Comparative cross-sectional. Objective: To measure the impact that COrona VIrus Disease-19 (COVID-19) has had on craniomaxillofacial (CMF) surgeons after 1 year and compare it with 2020 data by (1) measuring access to adequate personal protective equipment (PPE), (2) performance of elective surgery, and (3) the vaccination status. This should be investigated because most CMF surgeons felt that hospitals did not provide them with adequate PPE. Methods: The investigators surveyed the international AO CMF membership using a 30-item online questionnaire and compared it to a previous study. The primary predictor variable was year of survey administration. Primary outcome variables were availability of adequate personal protective equipment (adequate/inadequate), performance of elective surgery (yes/no), and vaccination status (fully vaccinated/partly vaccinated/not vaccinated). Descriptive and analytic statistics were computed. Binary logistic regression models were created to measure the association between year and PPE availability. Statistical significance level was set at P < .05. Results: The sample was composed of 523 surgeons (2% response rate). Most surgeons reported access to adequate PPE (74.6%). The most adequate PPE was offered in Europe (87.8%) with the least offered in Africa (45.5%). Surgeons in 2021 were more likely to report adequate PPE compared to 2020 (OR 3.74, 95% CI [2.59-4.39]). Most of the respondents resumed elective surgery (79.5% vs 13.3% in 2020) and were fully vaccinated (59.1%). Conclusions: Most CMF surgeons now have access to adequate PPE, resumed elective surgery, and are either fully or partly vaccinated. Future studies should investigate the long-term impact of the fast-evolving COVID-19 pandemic on CMF surgeons.

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.

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.

An analysis of patient dose received during cone-beam computed tomography in relation to scan settings and imaging indications as seen in a dental institution in order to establish institutional diagnostic reference levels.

OBJECTIVES: To investigate the dose-area product (DAP) of cone-beam computed tomography (CBCT) examinations for different scan settings and imaging indications, and to establish institutional diagnostic reference levels (DRLs) for dose optimisation. METHODS: A retrospective analysis of the DAP values of 3568 CBCT examinations taken from two different devices at the Prince Philip Dental Hospital, Hong Kong between 2016 and 2021 was performed. Patient- (age, gender, and imaging indication) and imaging-related (CBCT device, field-of-view (FOV), and voxel size) were correlated with the DAPs. The indication-oriented third-quartile DAP values were compared with DRLs from the UK, Finland, and Switzerland. The obtained third-quartile DAPs lower than the national DRLs and those for which no national DRLs have been proposed were used to establish institutional DRLs. RESULTS: In the investigated CBCTs, the DAP value for large FOV scans was significantly lower than medium/small FOVs. CBCTs with a small voxel size exhibited a significantly higher DAP than those with a medium/large voxel size. CBCTs for endodontic, periodontal, orthodontic, or orthognathic evaluation exhibited a significantly higher DAP than other indications. Twelve indication-oriented institutional DRLs were established and five of them were lower than the national DRLs: third molars (229 mGy×cm2), jaw cysts/tumours (410 mGy×cm2), maxillary sinus pathology (520 mGy×cm2), developing dentition (164 mGy×cm2), and periapical lesions (564 mGy×cm2). CONCLUSIONS: CBCT examinations for endodontic, periodontal, orthodontic, or orthognathic evaluation may deliver a higher radiation dose to the patient than other imaging tasks. A periodic review of the patient dose from CBCT imaging and establishment of institutional DRLs for specific clinical settings are needed for monitoring patient dose and to optimise indication-oriented scanning protocols.

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.