Lateral Cephalometric Radiographs Research Articles

A study on dislocation of the centre of rotation in nasomaxillary complex growth and development

ABSTRACT Purpose This study aimed to detect the centre of spiral similarity (CS), an improvement of the centre of rotation when the jaw shows standard growth, and to evaluate and examine the dislocation of CS depending on the skeletal type, sex and age. Materials and Methods This study included 107 patients aged 5–15 years (62 females and 45 males) examined at Osaka Dental University Hospital’s Department of Orthodontics for the primary complaint of malocclusion. For each patient, lateral cephalometric radiographs were taken before and after treatment. Skeletal types were classified into three groups (Class I, II and III) according to the McNamara analysis, and degrees of cervical vertebral maturation were classified into two groups (under 11 and 11 or over). We calculated CS using our previously reported method, derived the projective CS (pCS) to evaluate the dislocation of CS and compared pCS between skeletal groups. Results The CS of Class I was located approximately 17–21 mm anterior and 4–8 mm inferior to the sella. Significant differences in pCS were found between Classes I and III. Furthermore, the sign of pCS showed an opposite trend depending on sex. Conclusion The CS of ‘Class I and under 11’ is located near the spheno-ethmoidal synchondrosis, while that of ‘Class III and under 11’ was away from there in alternate directions for males and females. Our results provide insights into the trends that require different treatment strategies based on sex or other personal characteristics in orthodontics.

Lower Incisor-Pg: A New Cephalometric Parameter to Evaluate the Anterior Limit of Dentition.

Background: This present retrospective study aimed to introduce Lower Incisor-Pg and to assess how this new parameter varies with the skeletal sagittal and vertical relationships. Methods: A total of 1256 cephalometric analyses were performed using lateral cephalometric radiographs of a sample of subjects divided according to SN^Go-Gn, ANPg^, and IMPA measurements. The differences in Lower Incisor-Pg between the groups were assessed through ANOVA tests and posthoc analyses, while Pearson's correlation analysis was used to assess the correlations between the measurements. Results: The mesofacial growth pattern (61.0%) was more common than dolichofacial (30.0%) and brachyfacial (8.6%) ones in the sampled population. Regarding skeletal sagittal relationships, Class I was more frequent (70.9%) than Class II (19.3%) and Class III (9.8%). The mean value of the Lower Incisor-Pg was 3.2 ± 4.0 mm. Linear regression showed that the β coefficient was 0.45 and 0.36 for ANPg^ and SnGoGn^, respectively. Conclusions: Lower Incisor-Pg is a linear cephalometric measurement to evaluate the lower incisor sagittal position. For each degree of increase in ANPg^ and SNGoGn^, the Lower Incisor-Pg increased 0.45 mm and 0.36 mm, respectively.

Photogrammetric and Cephalometric Analyses of Ricketts' Esthetic Line in Malaysian Malay Adults: A Cross-sectional Study

Objective: To compare and correlate the Ricketts Esthetic Line measurement between photographs and lateral cephalogram. The norm for evaluating Ricketts' E-Line in the Malaysian Malay population is to be established. Materials and Methods: This was a cross-sectional study involving 126 pre-existing photographs and lateral cephalometric radiographs of skeletal Class I Malaysian Malay aged 19 to 40 recruited from the Orthodontic Clinic of Universiti Teknologi MARA (UiTM). Photogrammetric and cephalometric analyses of the upper and lower lips to Ricketts' E-line were performed. A paired t-test was performed to determine any statistically significant difference between the photographic and cephalometric variables. In addition, Pearson correlation was conducted to estimate the correlations between the photographic and cephalometric variables. Results: There was no significant difference between photographs and lateral cephalogram methods in the upper and lower lip to E-line measurement (p>0.05). For the photogrammetric analysis, the distance from the upper lip to the E-line was -0.30mm ±2.46, whereas the cephalometric analysis was -0.43mm ±2.63. The lower lip distance to the E-line for the photogrammetric analysis was 1.44mm ±2.8, whereas the cephalometric analysis was 1.24mm ±3.08. The Pearson correlation coefficient (r) for photographs and lateral cephalometric variables was close to 1 (0.914 and 0.898, respectively), indicating a robust positive correlation between the two variables. Conclusions: Photographic and cephalometric analysis can be used synonymously in measuring the Ricketts E line. Malaysian Malay has a more protrusive upper and lower lip to the E-line, compared to Caucasians, and the norm for the investigated population was established.

Effect of SEC III protocol on upper airway dimensions in growing class III patients: a retrospective study

BackgroundThe primary objective of the study was to evaluate the effects of SEC III (Splints, Class III Elastics, and Chin cup) protocol on the upper airway dimensions using lateral cephalometric radiographs. The secondary objectives were to evaluate the skeletal and dental effects of the SEC III protocol using lateral cephalometric radiographs.MethodsThe pre- and post-treatment lateral cephalometric radiographs of 24 patients treated using the SEC III protocol were used to address the aim of the study. Children in the pre-pubertal (CS-1 or CS-2) or circumpubertal (CS-3 or CS-4) skeletal maturation stage and having class III dentoskeletal malocclusion were included in the study. Patients with a history of previous orthodontic treatment, maxillofacial surgery or trauma, tonsillectomy, adenoidectomy, or craniofacial malformations were excluded. The pre-treatment and post-treatment lateral cephalometric radiographs were traced, then airway measurements, skeletal measurements, and dental measurements were performed. The results were analysed using paired samples t-test or Wilcoxon signed rank test according to the data normality.ResultsData of 6 males and 18 females were analysed (Mean age = 11.21 ± 1.02 years). Duration of active treatment was 5.75 ± 1.03 months. Treatment using SEC III protocol resulted in a significant increase in ANB angle (2.92 ± 1.50 degrees, p < 0.001) and Wits appraisal (3.31 ± 1.99 mm) (p < 0.001). The increase in the mandibular plane angle (0.75 ± 1.42 degrees, p = 0.02) and the maxillary length (2.29 ± 2.69 mm, p < 0.001) was statistically significant. Contrarily, the mandibular length did not change significantly (p = 0.10). The maxillary incisors were significantly proclined (4.38 ± 4.28 degrees; p < 0.001), while the mandibular incisors were significantly retroclined (-5.79 ± 6.21 degrees; p < 0.001) following treatment. The change in the nasopharyngeal airway and the retropalatal airway was not statistically significant. The middle and inferior pharyngeal space (retroglossal airway) significantly decreased by 1.33 ± 1.97 mm (p = 0.003) and 1.96 ± 2.48 mm (p = 0.001), respectively.ConclusionsEarly class III correction using SEC III protocol reduced the retroglossal airway dimensions but did not affect the nasopharyngeal and retropalatal airway dimensions. Correction of the class III dentoskeletal relationship was obtained through both skeletal and dental changes.

Influence of Digit Sucking Habit on Masseter Muscle Thickness and Upper Airway Dimensions in Nigerian Children

Background: Digit sucking habit (DSH) generates functional forces that can influence craniofacial morphology. Although the dental effects have been widely reported, its influence on the masseter muscle thickness (MMT) and upper airway (UA) dimensions is not well known.&#x0D; &#x0D; Methods: Thirty (30) children selected from the orthodontic clinic (OAUTHC), with a DSH were matched with a group of 30 children without a DSH. Each group comprised of 16 males and 14 females. Ultrasonographic evaluation of the masseter muscle (MM) was performed to measure the left and right MMT in the relaxed and contracted states. Lateral cephalometric radiographs were obtained and 6 UA variables were measured on the x-ray. Data was analysed using SPSS version 20.0. Statistical significance was set at p&lt;0.05.&#x0D; Inferential statistics was done using independent sample t test to compare means.&#x0D; Results: Participants in the DS group had a mean age of 7.7 ± 2.2 years, whereas those in the non-DS group had a mean age of 8.1 ± 2.1 years. The MM was generally thicker among the DS group, both in the contracted and relaxed states when compared with the non-DS group, but these differences were not statistically significant (p&gt;0.05). The mean measurement of the width of the nasopharynx (P1) was significantly decreased among the DS group when compared with the non-DS group (p&lt;0.05). There was no statistically significant difference in the mean values for the width of the oropharynx (P2), hypopharynx (P3), soft palate length (PNS-U1) and thickness (MPT) and the posterior bony boundary of the nasopharynx (PNS-Ba) between both groups. (p&gt;0.05).&#x0D; Conclusion: Digit sucking habit caused a statistically significant narrowing of the width of the nasopharynx (p&lt;0.05). The MMT did not differ significantly between the DS and non-DS groups both in the relaxed and contracted states.

Validation of Machine Learning Models for Craniofacial Growth Prediction.

This study identified the most accurate model for predicting longitudinal craniofacial growth in a Japanese population using statistical methods and machine learning. Longitudinal lateral cephalometric radiographs were collected from 59 children (27 boys and 32 girls) with no history of orthodontic treatment. Multiple regression analysis, least absolute shrinkage and selection operator, radial basis function network, multilayer perceptron, and gradient-boosted decision tree were used. The independent variables included 26 coordinated values of skeletal landmarks, 13 linear skeletal parameters, and 17 angular skeletal parameters in children ages 6 to 12 years. The dependent variables were the values of the 26 coordinated skeletal landmarks, 13 skeletal linear parameters, and 17 skeletal angular parameters at 13 years of age. The difference between the predicted and actual measured values was calculated using the root-mean-square error. The prediction model for craniofacial growth using the least absolute shrinkage and selection operator had the smallest average error for all values of skeletal landmarks, linear parameters, and angular parameters. The highest prediction accuracies when predicting skeletal linear and angular parameters for 13-year-olds were 97.87% and 94.45%, respectively. This model incorporates several independent variables and is useful for future orthodontic treatment because it can predict individual growth.

Stability of anterior open bite cases treated with upper and lower extrusion arches in adults: a follow-up study.

To investigate the post-treatment stability of anterior open bite (AOB) cases treated with upper and lower extrusion arches in adults. 23 patients with AOB were treated with extrusion arches and evaluated for dentoskeletal changes using lateral cephalometric radiographs before treatment (T0), after treatment (T1), and 12 months post-treatment (T2). Patients received bondable tongue spurs and vacuum-formed retainers as post-treatment retention/stability measures for 12 months. Post-treatment stability was further assessed qualitatively by the Photographic Openbite Severity Index. All the cases showed positive overlap between the anterior teeth at the end of orthodontic treatment, and 20 of 23 treated patients attended the recall visit after 12 months. A total of 85% of the cases maintained positive overlap at least 1 year post-treatment, 10% showed edge-to-edge bite, and only 5% showed no overbite. Treatment of AOB in adults with extrusion arches proved to be stable 1 year post-treatment. Changes in the overbite after 1 year of follow-up were not significant.

Cephalometric radiograph-based approach for sex determination using maxillary sinus index in Surabaya, Indonesia

Accurate sex determination is a critical aspect of individual identification in various fields, including anthropology, forensic science, and archaeology. Various parameters from the skull, mandible, pelvis, and long bones are commonly utilized for this purpose. Recently, the potential of the maxillary sinus as a sex-discriminatory parameter has been studied by Khaitan et al. through the analysis of lateral cephalometric radiography. This study aimed to evaluate the feasibility of implementing the sex determination formula devised by Khaitan et al. for the adult population of Surabaya, Indonesia. For this purpose, 130 digital cephalometric radiographs of outpatients in the DHDC Dental Office in Surabaya, Indonesia, were assessed. The maxillary sinus height and width were measured to derive the maxillary sinus index (MSI) and calculate the discriminant score (D) for sex identification. This study revealed that the maxillary sinus’s average height in males was 37.111+5.13 mm, while in females, it was 34.538+4.36 mm. Males had an average maxillary sinus width of 44.152+4.11 mm, while in females it was of 38.849+3.33 mm. The MSI values for males (1.204±0.14) were higher than for females (1.135±0.10). The discriminant scores showed notable variations between males and females, with an 86% success rate for females and 27.8% for males. The present study provides evidence that the Khaitan formula can serve as a valuable complementary approach for sex determination in females. Sex determination based on the MSI is thought to be a population-dependent parameter in forensic sciences and requires careful interpretation in its application.

Cephalometric analysis performance discrepancy between orthodontists and an artificial intelligence model using lateral cephalometric radiographs.

The purpose of the present clinical study was to compare the Ricketts and Steiner cephalometric analysis obtained by two experienced orthodontists and artificial intelligence (AI)-based software program and measure the orthodontist variability. A total of 50 lateral cephalometric radiographs from 50 patients were obtained. Two groups were created depending on the operator performing the cephalometric analysis: orthodontists (Orthod group) and an AI software program (AI group). In the Orthod group, two independent experienced orthodontists performed the measurements by performing a manual identification of the cephalometric landmarks and a software program (NemoCeph; Nemotec) to calculate the measurements. In the AI group, an AI software program (CephX; ORCA Dental AI) was selected for both the automatic landmark identification and cephalometric measurements. The Ricketts and Steiner cephalometric analyses were assessed in both groups including a total of 24 measurements. The Shapiro-Wilk test showed that the data was normally distributed. The t-test was used to analyze the data (α = 0.05). The t-test analysis showed significant measurement discrepancies between the Orthod and AI group in seven of the 24 cephalometric parameters tested, namely the corpus length (p = 0.003), mandibular arc (p < 0.001), lower face height (p = 0.005), overjet (p = 0.019), and overbite (p = 0.022) in the Ricketts cephalometric analysis and occlusal to SN (p = 0.002) and GoGn-SN (p < 0.001) in the Steiner cephalometric analysis. The intraclass correlation coefficient (ICC) between both orthodontists of the Orthod group for each cephalometric measurement was calculated. Significant discrepancies were found in seven of the 24 cephalometric measurements tested between the orthodontists and the AI-based program assessed. The intra-operator reliability analysis showed reproducible measurements between both orthodontists, except for the corpus length measurement. The artificial intelligence software program tested has the potential to automatically obtain cephalometric analysis using lateral cephalometric radiographs; however, additional studies are needed to further evaluate the accuracy of this AI-based system.

Assessment of correlation between hand-wrist maturation and cervical vertebral maturation: a fractal analysis study

BackgroundTo investigate whether fractal dimension (FD) measurements from hand-wrist radiographs and lateral cephalometric radiographs are correlated with each other and with skeletal maturation stages.MethodsIn this retrospective study conducted on hand-wrist and lateral cephalometric radiographs obtained from patients between 2017 and 2023, hand-wrist maturation stages (HWMS) and cervical vertebral maturation stages (CVMS) of 144 subjects (6 to 17 years of age) were assessed radiographically. The participants were divided into nine groups (n = 16 each) based on HWMS. Fractal analysis was performed on the radiographs of the radius, the middle finger phalanges (proximal, medial and distal), and the cervical vertebral bodies (C2, C3, C4). Mean and standard deviation values, Spearman’s and Pearson correlation analyses, one-way ANOVA, Kruskal-Wallis H tests and Mann-Whitney-U test were used to evaluate the data.ResultsPositive correlations were found between the FD values of the radius and HWMS or CVMS (r = .559, P = .001, r = .528 P = .001 respectively). The FD values of the radius were positively correlated with those of all cervical vertebrae (C2, C3, C4), proximal and medial phalanges as well as age. FD values measured from the proximal phalanx, medial phalanx and radius showed significant differences among both HWMS and CVMS (P < .05). HWMS was strongly correlated with CVMS (r = .929, P = .001). Age was strongly correlated with HWMS (r = .795, P = .001) and CVMS (r = .756, P = .001). There was a significant difference in terms of age distribution among HWMS and CVMS (P < .05).ConclusionsFD measurements on hand-wrist radiographs can provide useful information for the assessment of skeletal maturation stage. Especially, FD measurements from the radius are important and more reliable to predict skeletal maturation stage.

Assessment of landmark detection in cephalometric radiographs with different conditions of brightness and contrast using the an artificial intelligence software.

To evaluate the reliability and reproducibility of an artificial intelligence (AI) software in identifying cephalometric points on lateral cephalometric radiographs considering four settings of brightness and contrast. Brightness and contrast of 30 lateral cephalometric radiographs were adjusted into four different settings. Then, the control examiner (ECont), the calibrated examiner (ECal), and the CEFBOT AI software (AIs) each marked 19 cephalometric points on all radiographs. Reliability was assessed with a second analysis of the radiographs 15 days after the first one. Statistical significance was set at p < 0.05. Reliability of landmark identification was excellent for the human examiners and the AIs regardless of the type of brightness and contrast setting (mean intraclass correlation coefficient >0.89). When ECont and ECal were compared for reproducibility, there were more cephalometric points with significant differences on the x-axis of the image with the highest contrast and the lowest brightness, namely N(p = 0.033), S(p = 0.030), Po(p < 0.001), and Pog'(p = 0.012). Between ECont and AIs, there were more cephalometric points with significant differences on the image with the highest contrast and the lowest brightness, namely N(p = 0.034), Or(p = 0.048), Po(p < 0.001), A(p = 0.042), Pog'(p = 0.004), Ll(p = 0.005), Ul(p < 0.001), and Sn(p = 0.001). While the reliability of the AIs for cephalometric landmark identification was rated as excellent, low brightness and high contrast seemed to affect its reproducibility. The experienced human examiner, on the other hand, did not show such faulty reproducibility; therefore, the AIs used in this study is an excellent auxiliary tool for cephalometric analysis, but still depends on human supervision to be clinically reliable.

Cephalometric Prediction of Risk Factors for Mandibular Third Molar Impaction

Background: Mandibular third molar impaction in adult patients is one of the most common problems in dental practice. However, limited data are available on the association between mandibular third molar impaction and craniofacial skeletal problems. Aim: This study aimed to establish a prediction model to evaluate the risk factors for mandibular third molar impaction. Methods: Panoramic and lateral cephalometric radiographs of orthodontic patients aged ≥20 years were obtained from the Tri-Service General Hospital. The radiographs were analyzed by a single examiner. Panoramic radiographs were used to evaluate the mandibular third molar impaction. Lateral cephalometric radiographs were used to evaluate five linear and six angular measurements to define the facial pattern of the participants. The association between cephalometric measurements and mandibular third molar impaction was determined using one-way analysis of variance and logistic regression analysis. Results: This study included 60 participants. The incidence of mandibular third molar impaction was associated with the mandibular plane angle (MPA) and mandibular length (Co-Gn) (P &lt; 0.001). The presence of mandibular third molar impaction was found to gradually increase with increasing MPA and decreasing mandibular length. Conclusion: Individuals with a greater MPA and lesser mandibular length had a higher incidence of mandibular third molar impaction.

Botulinum Toxin Injection into the Digastric Muscle: Current Clinical Use and a Report of Five Cases.

The present research aimed to review the clinical applications of botulinum toxin-A (BTX-A) injection into the anterior belly of the digastric muscle (ABDM) and to highlight the potential role of the BTX-A injection into ABDM in preventing postsurgical relapse. Five Class II malocclusion patients who underwent orthognathic surgery received BTX-A injections into both ABDM for the prevention of postoperative relapse. The relapse was evaluated using lateral cephalometric radiographs by comparing the postoperative cephalometric analyses at two different time points, postoperatively at 2 weeks (T1), and long-term, at 9 months after the surgical intervention (T2). The results demonstrated no significant differences between T2 and T1 for the Selle-Nasion-point A (SNA) angle, Selle-Nasion-point B (SNB) angle, point A-Nasion-point B (ANB) angle, mandibular length, and sagittal mandibular position. The patients exhibited stable occlusion without any signs of relapse after the surgery. A single BTX-A injection into the ABDM can effectively prevent postoperative relapse in Class II malocclusion patients, following orthognathic surgery. From a clinical perspective, in case of optimal dosage and procedure, BTX-A injection could be considered as the primary option for the prevention of postsurgical relapse for Class II malocclusion patients.

Cephalometric changes associated with MAD therapy

Study objectives: The main objectives of this study were to assess the effect of mandibular advancement device (MAD) therapy on the upper airway morphology, as well as the occurence of dental and skeletal side effects following 1-year MAD therapy in patients with mild to moderate obstructive sleep apnea (OSA). Methods: In this study we included 15 patients with mild to moderate OSA treated with MAD therapy. All subjects underwent sleep study and lateral cephalometric radiography at baseline and at 1-year follow-up. Lateral cephalograms were analyzed with respect to relevant variables. Results: MAD therapy reduced apnea-hypopnea index (AHI) from 22.9±5.9 to 9.7±4.5 events/h (P&amp;lt;0.001) after 1-year of therapy. Oral area enclosure (3697.0±372.4 vs. 3381.5±336.4 mm2, P&amp;lt;0.001), superior airway space width (8.9±2.0 vs. 10.0±2.0 mm2, P=0.039), soft palate width (10.9±1.0 vs. 9.8±1.4, P=0.005) and length (45.4±3.8 vs. 43.9±4.2 mm, P=0.033) were significantly larger with the MAD intra-orally. Additionally, the tongue length decreased (84.1±5.3 vs. 80.7±5.9 mm, P=0.002), while the tongue height increased significantly (27.0±2.4 vs. 29.9±2.5 mm, P=0.003) with the MAD intra-orally. There were no significant changes in skeletal and dental cephalometric variables after 1 year of MAD therapy. Conclusions: Our results show significant enlargement of the upper airway dimensions with the MAD intra-orally in patients with mild to moderate OSA. Although there were no significant changes in skeletal and dental cephalometric variables after 1 year of MAD therapy, close follow-up during MAD therapy is advisable to prevent potentially relevant occlusal changes.

Assessment of Various Mandibular Divergence Pattern or Vertical Cephalometric Pattern in Bangladeshi Adult Patients

Introduction : Orthodontic diagnosis as well as the treatment planning of the patients are affected by vertical dimention of face. Lateral cephalometric radiographs are used by orthodontists to find out the norms of different skeletal, dental and soft tissue variables. Present study was undertaken with the aim to assess the various mandibular divergence pattern or vertical cephalometric pattern in Bangladeshi adult orthodontic patients. Materials and methods : This cross sectional study was conducted with 120 pretreatment lateral cephalograms of Bangladeshi adult orthodontic patients who visited Dhaka Dental College Hospital (DDCH) for orthodontic treatment for the duration of six months. The angular measurement used in this study to assess the vertical divergence pattern or vertical cephalometric pattern was mandibular plane to anterior cranial base (MP-SN). Collected data were analyzed by SPSS software version 26 and statistical significance was set as p=0.05. Results : The study result showed that out of 120 orthodontic patients hypodivergent vertical cephalometric pattern found in 26.6% patients having ˂270 MP-SN angle and normodivergent, hyperdivergent pattern found in (45.8%), (27.5%) patients having 270 to ˂ 370 MP-SN angle and &gt; 370 MP-SN angle respectively. Sex of the patient was not significantly associated with the vertical cephalometric pattern (as p &gt;0.05). It was also observed that age was not statistically significantly different between male and female patients within each mandibular divergence pattern and across the three mandibular divergence patterns. Conclusion : Present study concluded that age and sex of Bangladeshi adult orthodontic patients were not significantly associated with different mandibular divergence pattern or vertical cephalometric pattern. In all the three vertical cephalometric pattern the MP-SN angle were greater in Bangladeshi female than Bangladeshi male patients. Update Dent. Coll. j: 2023; 13(2): 15-18

Cephalometric profile analysis between genders. A study protocol

Background: According to current American Association of Orthodontists guidelines, two-dimensional lateral and posteroanterior cephalometric radiographs are recognized as essential components of diagnostic imaging records in orthodontics. Cephalometry is defined as the discipline that analyzes the craniofacial complex in a segmented way, to study the interrelationships between its structures and understand how the growth or alteration of one of these structures can compromise the whole. Through cephalometry, it is possible to indicate the clinical approach for patients, involving dental therapy with intraoral appliances and physical therapy with continuous positive pressure in the upper airway. Objectives: Investigate possible differences in cephalometric anatomical patterns between genders. Methods: This study protocol follows the STROBE - Strengthening the Reporting of Observational Studies in Epidemiology guidelines. A convenience sample will be used, consisting of teleradiography (cephalograms) of adult patients of both genders, carried out in a private Dental Clinic, located in the city of São José dos Campos (SP), Brazil, by the established inclusion and exclusion criteria. Six angular and nine linear measurements will be used in the analysis of cephalometric measures according to the study protocol. The exams will be distributed into three groups and paired according to the value of the angle formed between point A nasion and point B nasion (ANB). Groups will be formed by exams with class 1 skeletal relationship (0o &lt; ANB angle ≤ 4º), group 2 with class 2 exams (ANB angle &gt; 4°), and group 3 formed by class 3 exams (ANB angle ≤ 0°). Considerations: In some cases, craniofacial changes may predict the risk of sleep-disordered breathing, such as obstructive sleep apnea (OSA). Increased length and thickness of the soft palate and hyoid bone in the mandibular plane and retrognathia are associated with the pathogenesis of OSA. Therefore, the etiology of sleep-disordered breathing may vary in patients according to gender, according to cephalometric analysis.

Characterization of labiomandibular movements induced after isolated LeFort I osteotomy in the surgical management of class III malocclusion.

Maxillary surgery alone can be proposed for the surgical management of class III malocclusion, but anticipating outcomes for the labiomental muscle complex is challenging due to the mandibular autorotation phenomenon. The objective of this study was to quantify the mandibular and labiomental movements induced by maxillary osteotomy alone in the management of class III malocclusion according to different clinical and surgical variables. The post-operative changes in mandibular and labiomental shapes were studied by geometric morphometry from the pre- and post-operative lateral cephalometric radiograph of 25 patients. The explanatory variables tested were maxillary advancement, maxillary rotation, and divergence. Soft tissues repositioning are different from postoperative mandibular repositioning after maxillary osteotomy. Neuromuscular adjustments of mandible depend on divergence and the maxillary rotation. Labiomental response only depends on divergence. The surgical procedure does not have the same bone-related and musculocutaneous effects on patients with the same class III malocclusion. It is therefore essential for surgeons to understand the effects of their procedure on musculocutaneous tissues in order to best anticipate post-operative outcomes.

Assessment of early dental arch growth modification with removable maxillary expansion by cone-beam computed tomography and lateral cephalometric radiographs: a retrospective study

BackgroundThis study evaluated the skeletal and dental changes of patients brought by early removable maxillary expansion (ERME) treatment to explore the clinical treatment effect of ERME on early dental arch growth modification.MethodsSubject children aged 6–10 years with a maxillary transverse deficiency received ERME treatment, cone-beam computed tomography (CBCT) and lateral cephalometric radiographs were measured before and after treatment, and statistical differences in the measured items were evaluated with corresponding statistical methods to explore the skeletal and dental changes.ResultsAfter ERME treatment, there was a statistical increase in the maxillary basal bone arch width, nasal cavity width, maxillary alveolar bone arch width, and maxillary dental arch width. A buccal inclination of the maxillary alveolar bone and a buccal inclination and buccal movement in the alveolar bone of maxillary first molars were found. The maxillary skeletal expansion was statistically greater than the dental expansion. Increases in the mandibular alveolar bone arch width and dental arch width happened after treatment. A decrease in angle ANB and an increase in Ptm-A, U1-SN, U1-PP, L1-MP, and L6-MP were found after treatment. No statistical changes in the growth pattern-related measured items were observed.ConclusionsERME could expand the maxillary basal bone arch width, nasal cavity width, maxillary alveolar bone arch width, and maxillary dental arch width. The maxillary skeletal expansion was greater than the dental expansion. Secondary increases in the mandibular alveolar bone and dental arch widths would happen after ERME. ERME would result in a mandibular advancement, a labial inclination of maxillary anterior teeth, and an increase of maxillary sagittal length, and would not change the patient’s growth pattern.Trial registrationThis study was approved by the Institutional Review Board of the West China Hospital of Stomatology, Sichuan University. (WCHSIRB-D-2020–446).

Correlation between Cranial Base, Mandible, and Hyoid Bone Position in Different Anteroposterior Skeletal Malocclusions: A Cephalometric Study

Abstract Background Development of malocclusion can be promptly recognized through an understanding of the optimal position of the bone structures in the orofacial system and their relationship to the cranial base and jaw base. The aim of this study was to assess the relationship between the cranial base, mandible, and hyoid bone in different anteroposterior skeletal malocclusions. Materials and Methods This retrospective study evaluated 120 lateral cephalometric radiographs of individuals aged between 15 and 30 years. The subjects were classified using Burstone's analysis into three groups based on the N perpendicular to point A and N perpendicular to point B. The collected lateral cephalograms of the selected individuals were analyzed using Nemoceph v.12 software (Nemotec, Spain). The nasion-sella-articulare (NSAr), hyoidale angle (C3HyD), sella-articulare-hyoid angle (SArHy), and nasion-sella-hyoid (NSHy) angles were measured and compared among all the three groups. Results In the present study, considering the various angles among the three study groups, a statistically significant difference was observed for the SArHy angle (p &lt; 0.05). However, the saddle angle (NSAr) and hyoidale angle (C3HyD) showed no statistically significant difference between the three study groups. Post hoc Bonferroni test was applied to compare the differences between two groups. A statistically significant difference (p &lt; 0.05) was observed between class I and class II and between class II and class III groups. Conclusion Though the findings of the present study concluded that there is no variation in saddle angle among the three groups, the significant association of SArHy angle among class I, class II, and class III skeletal relationships, suggests an adaptation of the hyoid bone position in various skeletal patterns. We also suggest that the posterior positioning of the hyoid bone is related to skeletal class II malocclusion, whereas a forward positioning of the hyoid bone is related to skeletal class III malocclusion.

Effect of body mass index on soft tissues in adolescents with skeletal class I and normal facial height.

The evaluation of soft tissues in patients undergoing orthodontic treatment plays a critical role in diagnosis and treatment planning. This study aims to evaluate the effect of body mass index (BMI) on facial soft tissues in skeletal Class I patients with normal vertical growth. The study included 72 patients with a normal vertical growth pattern (SN-GoGn 26-38°) and skeletal Class I (ANB 2‒4°) malocclusion. According to their BMI (kg/m2) values, the patients were divided into three groups of 24 individuals each: underweight (>5th percentile) (13 females, 11 males; mean age, 11.58 ± 1.95 years), normal weight (5‒85th percentile) (12 females, 12 males; mean age, 11.54 ± 1.95 years), overweight (85‒95th percentile) (12 females, 12 males; mean age, 11.62 ± 2.01 years). Soft tissue thickness and height measurements were made on lateral cephalometric radiographs. In all soft tissue thickness measurements, except for the nasion, the overweight weight group had higher values. In comparing the underweight and normal weight groups, statistically significant differences were found in the thickness measurements at the nasion and gnathion (p < 0.05). The differences in thickness measurements at the glabella, labiale superius, stomion, labiale inferius, pogonion, gnathion, and menton are statistically significant between the underweight and overweight groups (p < 0.005). Comparing the normal and overweight groups revealed statistically significant differences the thickness measurements at the glabella, labiale superius, stomion, pogonion and menton (p < 0.05).