Evaluating cranial landmarks for yaw orientation in natural head position: a 3D study.

OBJECTIVES: To assess the symmetry of various cranial anthropometric points used as references for yaw orientation in the natural head position (NHP), relative to the mid-sagittal plane. MATERIALS AND METHODS: A prospective analysis using tomography data from 55 patients was conducted. Radiopaque markers, placed on patients in NHP, facilitated head position recording in three planes, with subsequent digital transfer for orientation analysis. Symmetry of eight points (zygomaxillare, zygion, ectoconchion, frontozygomatic suture, stephanion, porion, mastoidale, condylion laterale) was measured against the mid-sagittal plane. RESULTS: Significant asymmetry was observed in the stephanion, frontozygomatic suture, and ectoconchion points (p < 0.05). No significant differences were found in the symmetry of other points (p > 0.05). CONCLUSIONS: Findings suggest that stephanion, frontozygomatic suture, and ectoconchion are unreliable for yaw orientation in NHP. Other points, combined with clinical measurements, may offer better reliability.

Evaluation of the diagnostic ability of the Fränkel manoeuvre to detect the contributing jaw in angle class II division 1 malocclusion.

BACKGROUND: A correct diagnosis of patients with an Angle Class II malocclusion is needed to guide treatment decisions toward the contributing jaw and to achieve better treatment outcomes. The aim of the study is to evaluate the diagnostic potential of the Fränkel manoeuvre (FM) for detecting the components determining sagittal discrepancy in Angle Class II division 1. MATERIALS AND METHODS: Anonymous questionnaires containing photographs were distributed totwo groups: general practitioner (GP) dentists and orthodontists. The level of the patient's profile aesthetics before (T0) and after (T1) the manoeuvre was determined using a 100 mm visual analog scale, and the 'profile improvement' score was defined as T1 minus T0. The diagnostic ability of the FM was calculated by comparison with lateral cephalometry as a reference standard using receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 102 respondents participated in the survey; 40 were orthodontists, and 62 were GP dentists. According to the post-FM images, the "profile improvement" score (T1-T0) was significantly greater in patients with mandibular retrusion than in those with maxillary protrusion (p < 0.05). The predictive power of FM, coinciding with the area under the ROC curve, was 0.62 for GPs and 0.78 for orthodontists. CONCLUSIONS: The FM method is a useful and accurate tool for diagnosing skeletal Angle Class II malocclusion etiology (mandibular retrusion or maxillary protrusion), especially when used by orthodontists.

Retrospective analysis of the upper airway anatomy and Sella turcica morphology across different skeletal malocclusions: a computerized technique.

OBJECTIVE: This study aimed to investigate the normal volumetric space and variations in the measurements of different landmarks in adults with different skeletal relations of the maxilla and the mandible based on CBCT data. The study also analyses these landmarks to locate any correlations. BACKGROUND: Numerous studies in orthodontics have found a relationship between orthodontic treatment and changes in the anatomy and function of the airway. Severe changes in airway morphology can cause breathing difficulties, lower quality of life, and even result in life-threatening conditions such as obstructive sleep apnoea. Consequently, orthodontic diagnosis and treatment planning require a thorough understanding of the airway space and its function. METHODS: The present retrospective study was conducted using CBCT records of 120 adult patients, containing 40 samples of each skeletal class (20 males and 20 females). The boundaries were defined for the 3 major regions: the nasopharynx, the oropharynx, and the hypopharynx. Various measurements were recorded across these regions, as well as selective cephalometric landmarks. The obtained data was used to calculate average and standard deviation, while regression analysis was used to evaluate correlations and t-test was used to test statistical significance of gender differences. RESULTS: The results demonstrate that skeletal Class III individuals exhibit a reduced airway volume in the nasopharynx compared to other groups, whereas skeletal Class II individuals displayed a diminished airway volume in the hypopharynx. A strong correlation was observed for Sella turcica parameters. There were no significant differences in skeletal parameters across genders. Nasopharynx cavity volume demonstrated significant differences between skeletal Class I-Class III as well as between skeletal Class II-Class III. Hypopharynx cavity volume also demonstrated significant differences between skeletal Class I-Class II and between skeletal Class II-Class III. CONCLUSION: The major findings are the presence of a reduced nasopharyngeal volume in skeletal Class III malocclusions while skeletal Class II individuals displayed a diminished hypopharyngeal volume, making these critical areas to consider during the diagnostic and orthodontic treatment planning stages. This study also revealed a consistent correlation between Sella turcica parameters across various facial skeletal profiles, with skeletal Class II patients exhibiting a distinct pattern and skeletal Class I and Class III demonstrating an average relationship.

Craniofacial features and incisor position design of esthetics population after orthodontic treatment.

OBJECTIVES: This study aims to provide craniofacial features and incisor position prediction models among esthetics population after orthodontic treatment. METHODS: A total of 338 patients with esthetic profiles were selected from 1 055 post-orthodontic adults based on inclusion and exclusion criteria and scored by five dental students. Mean values of cephalometric measurement were demonstrated with gender and sagittal skeletal pattern (ANB) differences assessed by generalized estimating equation. Correlations among age, skeletal, and soft tissue variables in different genders were determined. Multivariate analysis was used to assess the influence of skeletal and soft tissue variables on orthodontic incisor position. RESULTS: Within the esthetic cohort after orthodontic treatment, gender differences existed in cranial and mandibular length, mandibular rotation, protrusion of pogonion, inclination of maxillary incisors, upper lip thickness, lower 1/3 face height, and nose protrusion. However, in class Ⅰ malocclusion, the development of the chin showed no significance, whereas the protrusion of the lower lip significantly differed between genders, with less protrusion in males. In males, the protrusion of lip and chin varied among groups, with thinner basic upper lip thickness of class Ⅱ than class Ⅰ and greater lower lip height of class Ⅲ than class Ⅰ. In females, the protrusion and height of the upper lip and chin varied in groups, with thicker basic upper lip thickness of class Ⅲ than class Ⅰ. Upper lip thickness, female basic upper lip thickness, and female lower lip height were correlated with age. The protrusion of the upper lip was mainly correlated with posterior cranial base, mandibular body length, ANB in male and SNA, ANB, sagittal maxillary length, mandibular rotation, and protrusion of pogonion in female. The protrusion of the lower lip in males was mainly correlated with ramus height, mandibular rotation, protrusion of pogonion in male and ANB, mandibular rotation, and protrusion of pogonion in females. After employing skeletal variables to fit dental parameters, optimal results were achieved in male IMPA (adjusted R2=0.712) and female G Vert-U1 (adjusted R2=0.795). After employing skeletal and soft tissue variables simultaneously, optimal results were achieved in male and female G Vert-U1, which was mainly influenced by the protrusion of the chin and nasal base in males (adjusted R2=0.836) and the protrusion of the nasal base as well as ANB in females (adjusted R2=0.842). CONCLUSIONS: This study demonstrated the craniofacial features of esthetics population after orthodontic treatment and revealed the correlation of gender, age, skeleton, and soft tissues to provide reliable prediction models for aesthetic orthodontic incisor position.

Prediction on the chin advancement of the twin block functional appliance in growing Chinese patients using the cephalometric markers: a retrospective study.

In spite of the widespread use of functional appliances, broad variations were applied the treatment response. The aim of this study is to investigate the pre-treatment cephalometric predictors on the chin advancement of twin-block in growing Chinese patients with class II malocclusion. After screening, 90 patients treated by twin-block were included in the study. The treatment outcome was assessed by the alterations in the distance of skeletal pogonion (Pog) to the vertical reference plane perpendicular to the Frankfurt plane (ΔPog-VRP). Moreover, ΔPog-VRP was divided by the cranial growth indicated by the Nasion to Basion changes (ΔN-Ba) to minimize the growth discrepancy among individuals (adjΔPog-VRP). Patients with ΔPog-VRP/adjΔPog-VRP above the median value were categorized into good response group (GRG/adjGRG, N = 45), while the rest were poor response group (PRG/adjPRG, N = 45). Independent t-test was used to compare the pre-treatment cephalometric measurements between GRG/adjGRG and PRG/adjPRG. Stepwise multivariate regression models were used to determine the pre-treatment cephalometric predictors for the chin advancement. Generally, there were not any significant differences between GRG/adjGRG and PRG/adjPRG regarding age, gender and cervical stage before twin-block treatment. Patients from GRG had significantly reduced cephalometric measurements in the vertical dimensions, including ∠N-Go-Me, ∠Mandibular plane-Occlusal plane (∠MP-OP) and the sum of angles (p < 0.05) in comparison to PRG. When the individual growth was taken account, similar findings were observed. The patients from adjGRG had a significantly lower ∠Sella Nasion line-MP (∠SN-MP), ∠Ar-Go-Me and ∠N-Go-Me, as well as an increased Posterior facial height (PFH)/Anterior facial height (AFH) (p < 0.05) compared with their counterparts. ∠N-Go-Me variable was the independent predictor on Pog advancement with (ß = -0.26, 95% CI: -0.06 to -0.01, p = 0.01) and without (ß = -0.29, 95% CI: -0.06 to -0.01, p < 0.01) adjustments on individual growth. The results of this study showed that patients with a reduced N-Go-Me angle are more likely to experience a greater chin advancement following twin-block treatment.

Predicting newborn birth outcomes with prenatal maternal health features and correlates in the United States: a machine learning approach using archival data.

BACKGROUND: Newborns are shaped by prenatal maternal experiences. These include a pregnant person's physical health, prior pregnancy experiences, emotion regulation, and socially determined health markers. We used a series of machine learning models to predict markers of fetal growth and development-specifically, newborn birthweight and head circumference (HC). METHODS: We used a pre-registered archival data analytic approach. These data consisted of maternal and newborn characteristics of 594 maternal-infant dyads in the western U.S. Participants also completed a measure of emotion dysregulation. In total, there were 22 predictors of newborn HC and birthweight. We used regularized regression for predictor selection and linear prediction, followed by nonlinear models if linear models were overfit. RESULTS: HC was predicted best with a linear model (ridge regression). Newborn sex (male), number of living children, and maternal BMI predicted a larger HC, whereas maternal preeclampsia, number of prior preterm births, and race/ethnicity (Latina) predicted a smaller HC. Birthweight was predicted best with a nonlinear model (support vector machine). Occupational prestige (a marker similar to socioeconomic status) predicted higher birthweight, maternal race/ethnicity (non-White and non-Latina) predicted lower birthweight, and the number of living children, prior preterm births, and difficulty with emotional clarity had nonlinear effects. CONCLUSIONS: HC and birthweight were predicted by a variety of variables associated with prenatal stressful experiences, spanning medical, psychological, and social markers of health and stress. These findings may highlight the importance of viewing prenatal maternal health across multiple dimensions. Findings also suggest that assessing difficulties with emotional clarity during standard obstetric care (in the U.S.) may help identify risk for adverse newborn outcomes.

Relationship between craniofacial skeletal patterns and anatomic characteristics of masticatory muscles: a systematic review and meta-analysis.

BACKGROUND: The anatomic characteristics of the masticatory muscles differ across craniofacial skeletal patterns. OBJECTIVE: To identify differences in the anatomic characteristics of masticatory muscles across different sagittal and vertical craniofacial skeletal patterns. ELIGIBILITY CRITERIA: Studies measuring the thickness, width, cross-sectional area (CSA), volume and orientation of masticatory muscles in healthy patients of different sagittal (Class I, Class II, and Class III) and/or vertical (normodivergent, hypodivergent, and hyperdivergent) patterns. INFORMATION SOURCES: Unrestricted literature searches in 8 electronic databases/registers until December 2023. RISK OF BIAS AND SYNTHESIS OF RESULTS: Study selection, data extraction, and risk of bias assessment with a customised tool were performed independently in duplicate. Random-effects meta-analysis and assessment of the certainty of clinical recommendations with the GRADE approach were conducted. RESULTS: 34 studies (37 publications) were selected with a total of 2047 participants and data from 16 studies were pulled in the meta-analysis. Masseter muscle thickness in relaxation was significantly greater by 1.14 mm (95% CI 0.74-1.53 mm) in hypodivergent compared to normodivergent patients while it was significantly decreased in hyperdivergent patients by - 1.14 mm (95% CI - 1.56 to - 0.73 mm) and - 2.28 mm (95% CI - 2.71 to - 1.85 mm) compared to normodivergent and hypodivergent patients respectively. Similar significant differences were seen between these groups in masseter muscle thickness during contraction as well as masseter muscle CSA and volume. Meta-analyses could not be performed for sagittal categorizations due to insufficient number of studies. CONCLUSIONS: Considerable differences in masseter muscle thickness, CSA and volume were found across vertical skeletal configurations being significantly reduced in hyperdivergent patients; however, results should be interpreted with caution due to the high risk of bias of the included studies. These variations in the anatomic characteristics of masticatory muscles among different craniofacial patterns could be part of the orthodontic diagnosis and treatment planning process. REGISTRATION: PROSPERO CRD42022371187 .

Classification of cervical vertebral maturation stages with machine learning models: leveraging datasets with high inter- and intra-observer agreement.

OBJECTIVES: This study aimed to assess the accuracy of machine learning (ML) models with feature selection technique in classifying cervical vertebral maturation stages (CVMS). Consensus-based datasets were used for models training and evaluation for their model generalization capabilities on unseen datasets. METHODS: Three clinicians independently rated CVMS on 1380 lateral cephalograms, resulting in the creation of five datasets: two consensus-based datasets (Complete Agreement and Majority Voting), and three datasets based on a single rater's evaluations. Additionally, landmarks annotation of the second to fourth cervical vertebrae and patients' information underwent a feature selection process. These datasets were used to train various ML models and identify the top-performing model for each dataset. These models were subsequently tested on their generalization capabilities. RESULTS: Features that considered significant in the consensus-based datasets were consistent with a CVMS guideline. The Support Vector Machine model on the Complete Agreement dataset achieved the highest accuracy (77.4%), followed by the Multi-Layer Perceptron model on the Majority Voting dataset (69.6%). Models from individual ratings showed lower accuracies (60.4-67.9%). The consensus-based training models also exhibited lower coefficient of variation (CV), indicating superior generalization capability compared to models from single raters. CONCLUSION: ML models trained on consensus-based datasets for CVMS classification exhibited the highest accuracy, with significant features consistent with the original CVMS guidelines. These models also showed robust generalization capabilities, underscoring the importance of dataset quality.

Correlation of skeletal development and midpalatal suture maturation.

OBJECTIVES: The aim of our study is to determine the relationship between MPS maturation and CVM stage determined from CBCTs. MATERIALS AND METHODS: CBCT images of 130 individuals (75 females, 55 males) with a mean age of 15.04 ± 3.11 (9.56-25.05 years) were analyzed. Images were analyzed using the i-CAT Vision software program. The cephalometric images to be examined were also obtained from the same CBCT images with the ImageJ program. The correlation between MPS and CVM stages was evaluated using the Spearman correlation test. The relationship between the skeletal developmental stage and MPS maturation, as assessed by the CVM method, was evaluated with the positive likelihood ratio. RESULTS: Significant correlations were found between CVM and MPS maturation stages. Positive LHR values of cervical vertebral stages were obtained to define the maturation stages of the midpalatal suture. LHR values greater than ten were found between CS2, CS5, and CS6 and maturation stages B, D, and E, respectively. A 15-30% correlation was observed between CS3 and CS4 maturation stages B and C, respectively. A positive correlation of 15% was found between CS3 and stage C. CONCLUSION: MPS fusion is more likely to occur after CS4. The correlation between the CVM and MPS maturation stages is significant (r = 0.858). CVM stages CS2, CS4, and CS6 can be a preliminary indicator for MPS stages B, D, and E, respectively. CS5 shows that MPS fusion has occurred partially or completely. CLINICAL RELEVANCE: A significant relationship exists between skeletal developmental stages and suture maturation.

[Early treatment of Class â ¢ malocclusion based on craniomaxillofacial growth and development].

More and more attention has been paid to the early treatment of malocclusion, especially the early treatment of class Ⅲ malocclusion. Class Ⅲ malocclusion not only affects maxillofacial growth and development, occlusal function and facial beauty, but also leads to serious physical and mental problems. Focusing on class Ⅲ malocclusion, the definition, classification, etiological mechanism, craniofacial growth and development rule, and the influence of early treatment on craniofacial growth and development were reviewed. In class Ⅲ patients, the craniofacial growth and development should be evaluated and analyzed when the early intervention carried out. The purpose of treatment of class Ⅲ malocclusion is achieved by using the appliance to affect the craniomaxillofacial growth.

[A comparative study of the efficacy of customized titanium plates versus conventional maxillary protraction in the treatment of skeletal class â ¢ patients].

Objective: To compare the clinical efficacy of customized titanium plate and conventional maxillary protraction treatment in patients with skeletal class Ⅲ malocclusion during growth spurt. Methods: During growth spurt, skeletal class Ⅲ patients with maxillary hypoplasia who were treated in the Department of Orthodontics, Capital Medical University School of Stomatology from August 2018 to July 2021 were prospectively enrolled. They were treated with maxillary protraction using customized titanium plates (customized titanium plate group) and conventional methods (conventional protraction group), respectively. Lateral cephalometric radiographs were collected before and after treatment for conventional cephalometric analysis, including SNA angle (angle between Sella, Nasion and A point), ANB angle (angle between A point, Nasion, and B point), FH-MP angle (mandibular plane angle), Y-axis angle, U1-L1 angle (upper to lower central incisor angle), U1-SN angle (upper incisor to SN plane angle), anterior and lower height, maxillary length, etc. The stable basicranial line (SBL) was used as the reference line to measure the distance from each reference point (ANS point, A point, Prn point, Sn point, UL point etc.) to the stable basicranial vertical line (VerT, the perpendicular line of the skull base line at the intersection point of the anterior wall of the sella image and the inferior edge of the anterior bed process). Paired t-tests were performed on the cephalometric data before and after maxillary protraction treatment in the two groups, and two independent samples t-tests were performed to compare the differences in the efficacy of the two maxillary protraction methods. Results: A total of 20 patients (9 males and 11 females), aged (10.8±1.3) years, were included in the personalized titanium plate group. A total of 20 patients (8 males and 12 females), aged (10.5±1.1) years, were included in the conventional protraction group. The SNA angle, ANB angle, FH-MP angle, Y-axis angle, anterior lower height, maxillary length, ANS-VerT distance, A-VerT distance, Prn-VerT distance, Sn-VerT distance, and UL-VerT distance were significantly higher than those before treatment in the two groups (P<0.05). The changes of SNA angle, ANB angle and A-VerT before and after treatment in the personalized titanium plate group [3.15°±2.28°, 4.64°±1.40°, (4.41±3.43) mm, respectively] were significantly higher than those in the traditional group [2.13°±2.69°, 2.81°±1.10°, (3.13±4.76) mm, respectively](P<0.05), and the changes of U1-L1 angle and U1-SN angle before and after treatment (-0.76°±7.42° and 1.74°±6.38°, respectively) was significantly lower than that of the control group (-5.14°±6.62° and 4.57°±5.24°, respectively, P<0.05). Conclusions: Maxillary protraction can effectively improve skeletal class Ⅲ relationships in growing patients. The linear measurements using the SBL line as a reference plane visualize the sagittal improvement in sagittal relationship after maxillary protraction. The customized titanium plate maxillary protraction treatment has a clear therapeutic effect on patients with skeletal class Ⅲ deformities, and its dental effect is relatively small.

Lateral cephalometric parameters among Arab skeletal classes II and III patients and applying machine learning models.

BACKGROUND: The World Health Organization considers malocclusion one of the most essential oral health problems. This disease influences various aspects of patients' health and well-being. Therefore, making it easier and more accurate to understand and diagnose patients with skeletal malocclusions is necessary. OBJECTIVES: The main aim of this research was the establishment of machine learning models to correctly classify individual Arab patients, being citizens of Israel, as skeletal class II or III. Secondary outcomes of the study included comparing cephalometric parameters between patients with skeletal class II and III and between age and gender-specific subgroups, an analysis of the correlation of various cephalometric variables, and principal component analysis in skeletal class diagnosis. METHODS: This quantitative, observational study is based on data from the Orthodontic Center, Jatt, Israel. The experimental data consisted of the coded records of 502 Arab patients diagnosed as Class II or III according to the Calculated_ANB. This parameter was defined as the difference between the measured ANB angle and the individualized ANB of Panagiotidis and Witt. In this observational study, we focused on the primary aim, i.e., the establishment of machine learning models for the correct classification of skeletal class II and III in a group of Arab orthodontic patients. For this purpose, various ML models and input data was tested after identifying the most relevant parameters by conducting a principal component analysis. As secondary outcomes this study compared the cephalometric parameters and analyzed their correlations between skeletal class II and III as well as between gender and age specific subgroups. RESULTS: Comparison of the two groups demonstrated significant differences between skeletal class II and class III patients. This was shown for the parameters NL-NSL angle, PFH/AFH ratio, SNA angle, SNB angle, SN-Ba angle. SN-Pg angle, and ML-NSL angle in skeletal class III patients, and for S-N (mm) in skeletal class II patients. In skeletal class II and skeletal class III patients, the results showed that the Calculated_ANB correlated well with many other cephalometric parameters. With the help of the Principal Component Analysis (PCA), it was possible to explain about 71% of the variation between the first two PCs. Finally, applying the stepwise forward Machine Learning models, it could be demonstrated that the model works only with the parameters Wits appraisal and SNB angle was able to predict the allocation of patients to either skeletal class II or III with an accuracy of 0.95, compared to a value of 0.99 when all parameters were used ("general model"). CONCLUSION: There is a significant relationship between many cephalometric parameters within the different groups of gender and age. This study highlights the high accuracy and power of Wits appraisal and the SNB angle in evaluating the classification of orthodontic malocclusion.

Genetic and environmental contributions to the development of soft tissue facial profile: a twin study.

OBJECTIVES: This study aimed to determine the relative contribution of genetic and environmental factors in the phenotypic variation of the soft tissue facial profile during the mixed dentition and the permanent dentition stages. METHODS: In this retrospective cohort study, standardized facial profile photographs of 139 twin pairs (55 monozygotic and 84 dizygotic) were obtained from archival records at the Adelaide Dental School. Photographic analysis used 12 angular and 14 linear facial profile measurements from the mixed dentition (7-11 years) to the permanent dentition (12-17 years) stages. A genetic analysis was performed using a univariate structural equation model adhering to the normal assumptions of a twin model. RESULTS: In the mixed dentition stage, the additive genetic (A) and unique environment (E) model, AE model, was the most parsimonious in explaining the observed phenotypic variance for all 26 facial traits with the narrow-sense heritability estimates ranging between 0.38 and 0.79. In the permanent dentition, the AE model was the most parsimonious for 20 out of 26 traits, however, the variance of six traits, particularly those in the lower third of the face, was best explained by the shared environmental and unique environmental factors. LIMITATIONS: This study exclusively included twins of European ancestry. CONCLUSIONS: The soft tissue facial profile demonstrated dynamic genetic and environmental influences with a greater additive genetic influence during the mixed dentition and the early stages of the permanent dentition. However, there was evidence of increasing environmental influence in the lower third of the face during the early stages of the permanent dentition.

Efficacy of modified anterior maxillary segmental distraction osteogenesis based on 3D visualisation for the treatment of maxillary hypoplasia among adolescents with cleft lip and palate.

BACKGROUND: This study evaluates a three-dimensional (3D) visualisation design combined with customized surgical guides to assist anterior maxillary segmental distraction osteogenesis (AMSDO) in correcting maxillary hypoplasia in adolescents with cleft lip and palate (CLP), focusing on treatment outcomes, satisfaction and the validity of 3D planning. METHODS: This retrospective cohort study was conducted at a single hospital in China. Between January 2020 and December 2023, 12 adolescents with CLP with maxillary hypoplasia were included. An advanced 3D simulation was used to convey the treatment strategy to the patients and their families. A customized surgical guide and distraction osteogenesis device were designed. Cephalometric analysis evaluated AMSDO changes and long-term stability. Patient satisfaction was assessed. The Chinese version of the Child Oral Health Impact Profile was used to evaluate the children's oral health-related quality of life before and after treatment. The postoperative outcomes were compared with the planned outcomes by superimposing the actual postoperative data onto the simulated soft tissue models and calculating the linear and angular differences between them. RESULTS: One patient experienced postoperative gingivitis, yielding an 8.33% complication rate. Most patients (83.33%) were highly satisfied with the target position, with the rest content. Cephalometric analysis showed significant improvements in various indices post-traction. Quality-of-life scores significantly improved post-treatment. The discrepancies in facial soft tissue between the simulated and actual results were within clinically satisfactory ranges. CONCLUSIONS: Digitally designed surgical guides effectively treat maxillary hypoplasia in adolescents with CLP, ensuring stability, reducing complications, reducing dependency on operator experience, and enhancing satisfaction and health outcomes. Although the simulated results were clinically acceptable, it is important to inform patients of potential variations in the predicted soft tissue.

Craniometric determinants of the fitted filtration efficiency of disposable masks.

Introduction: Exposure to harmful aerosols is of increasing public health concern due to the SARS-CoV-2 pandemic and wildland fires. These events have prompted risk reduction behaviors, notably the use of disposable respiratory protection. This project investigated whether craniofacial morphology impacts the efficiency of disposable masks (N95, KN95, surgical masks, KF94) most often worn by the public to protect against toxic and infectious aerosols. This project was registered with ClinicaltTrials.gov (NCT05388201; registration May 18, 2022). Methods: One-hundred participants (50 men, 50 women) visited the Environmental Protection Agency's Human Studies Facility in Chapel Hill, NC between 2022-2023. Craniometrics and 3D scans were used to separate participants into four clusters. Boosting and elastic net regression yielded five measurements (bizygomatic breadth, nose length, bizygomatic nasal arc, neck circumference, ear breadth) that were the best predictors of filtration efficiency based on overall model fit. Fitted filtration efficiency was quantified for each mask at baseline and when tightened using an ear-loop clip. Results: The mean unmodified mask performance ranged from 55.3% (15.7%) in the large KF94 to 69.5% (12.3%) in the KN95. Modified performance ranged from 66.3% (9.4%) in the surgical to 80.7% (12.0%) in the KN95. Clusters with larger face width and neck circumference had higher unmodified mask efficiency. Larger nose gap area and nose length decreased modified mask performance. Discussion: We identify face width, nose size, nose shape, neck circumference, and ear breadth as specific features that modulate disposable mask fit in both unmodified and modified conditions. This information can optimize guidance on respiratory protection afforded by disposable ear-loop masks.

Effects of bone anchored maxillary protraction on patients with unilateral cleft lip/palate or isolated cleft palate and hypoplastic maxilla: a 6-year follow-up case control study.

OBJECTIVES: To evaluate the effects of bone-anchored maxillary protraction (BAMP) treatment and longterm stability in growing cleft lip and palate and isolated cleft palate (CLP/CP) patients with mild maxillary hypoplasia and to compare maxillary growth patterns of BAMP-treated patients to matched control CLP/CP patients. MATERIALS AND METHODS: Ten patients with CLP/CP were treated with BAMP; they were compared to the maxillary growth pattern of 10 age-matched cleft control patients with no maxillary protraction treatment, who later received surgical Le Fort I maxillary advancement after the growth period. The assessment of maxillary growth and the occlusion started at mean 8 years of age and continued until mean 18 years of age. RESULTS: The use of BAMP orthopedic traction changed the growth pattern of mild hypoplastic maxilla toward a more anterior direction and advanced the face even above the level of Le Fort lll with only a minor effect on dentoalveolar units. The correction of occlusion and facial convexity were stable in the long term. CONCLUSIONS: The using BAMP may improve the position of the maxilla relative to the anterior cranial base for the correction of mild maxillary hypoplasia in adolescent patients with CLP/CP. The achieved results are rather stable in the long term.