Convex Profile Research Articles

Management Of Skeletal Class Ii Malocclusion With Twin Block And Headgear: A Case Report

Background. The main concern of patients and their parents seeking orthodontic treatment has always been the sagittal relationship between the jaws and dentition. The most commonly observed sagittal problems are skeletal class II maxillomandibular relationship which affects about one-third of the examined patients who seek orthodontic treatment. This case report demonstrates the use of the Twinblock appliance and high-pull headgear in a skeletal Class II Division 1 patient with a prognathic maxilla and a retrognathic mandible. A 9 year old male patient reported to Department of Paediatric and Preventive Dentistry with a chief complaint of forwardly placed upper front teeth. On extraoral examination, it was found that the patient had a convex profile, incompetent lips, increased maxillary anterior teeth visibility, acute nasolabial angle, receded chin and deep mento labial sulcus. Superimposition of Post treatment with pre-treatment lateral cephalograms showed a reduction in the sagittal discrepancy. With the retraction and intrusion of maxillary anteriors by the use of head gear along with mandibular advancement by the use of twinblock gave the desired result.

Soft Tissue Facial Morphology in Growing Patients with Different Occlusal Classes.

The study of facial profiles in the dental field is very important for the diagnosis and the dental and orthodontic treatment plan. The aim of this study is to analyze the three-dimensional morphology of the faces of 269 growing patients with Class I and II occlusions, focusing on children aged between 6 and 9 years old. The analysis was conducted using a non-invasive computerized system, which allowed for the automatic collection of facial landmarks and the subsequent reconstruction of three-dimensional coordinates. The sample comprised 269 children within the specified age range. Each child's facial features were captured using the non-invasive computerized system, which utilized two infrared CCD cameras, real-time hardware for label recognition, and software for three-dimensional landmark reconstruction. Sixteen cutaneous facial landmarks were automatically collected for each participant. From these landmarks, 10 angular and 15 linear measurements, as well as five direct distance rates, were derived. The mean values for each age class were calculated separately for children with bilateral Angle Class I occlusion and compared with those for children with bilateral Class II occlusion. In all children, the left and right occlusal classes were measured as suggested by Katz. The analysis revealed notable differences, primarily in the three-dimensional angular measurements between children with Class I and II occlusions. Specifically, Class II children exhibited more convex faces in the sagittal plane and a less prominent lower jaw compared to Class I children. However, no significant differences were observed in linear measurements, except for the lower facial height rate, which varied inconsistently across age groups between the two occlusion types. the findings of this research highlight distinct three-dimensional facial morphological differences between children with Class I and II occlusions. While Class II children tended to have more convex facial profiles and less prominent lower jaws, linear measurements showed minimal variation between the two occlusion types. These results underscore the importance of three-dimensional analysis in understanding facial morphology in growing patients with different occlusal patterns.

Enhancing cathode design by considering complex motion and variations of electric field distribution in counter-rotating electrochemical machining

The counter-rotating electrochemical machining (CRECM) shows unique potential in the machining of thin-walled rotating parts with complex convex structures. CREM realizes the shaping of complex convex structures through the relative rotation of the cathode and anode. The complex motion pattern and electric field distribution make it difficult to apply the existing cathode design methods to CRECM. To solve this problem, the matrix equations of cathode motion based on the kinematics and the electric field simulation model are established. The motion trajectories and edge contours at different angles are analyzed. The rotational overlap theory of motion trajectories under the windows at different angles is proved. Besides, the relationship between electric field distribution and the convex structure forming under different angle windows is studied, and the fundamental reason for deviations occurs when the convex profile is rotated to coincide is revealed. Therefore, a prediction model of the sidewall dissolution is established to correct this deviation, thereby deriving a high-precision design formula for the cathode windows of the high convex structures. By designing a cathode with oval-like windows to curry out CRECM experiments, the array-arranged (30×5) circular high convex structure with a maximum roundness error of 0.065 mm is successfully fabricated.

Transmission interference fringe (TIF) technique for the dynamic visualization of evaporating droplet

The transmission interference fringe (TIF) technique was developed to visualize the dynamics of evaporating droplets based on the Reflection Interference Fringe (RIF) technique for micro-sized droplets. The geometric formulation was conducted to determine the contact angle (CA) and height of macro-sized droplets without the need for the prism used in RIF. The TIF characteristics were analyzed through experiments and simulations to demonstrate a wider range of contact angles from 0 to 90°, in contrast to RIF's limited range of 0–30°. TIF was utilized to visualize the dynamic evaporation of droplets in the constant contact radius (CCR) mode, observing the droplet profile change from convex-only to convex-concave at the end of dry-out from the interference fringe formation. The TIF also observed the contact angle increase from the fringe radius increase. This observation is uniquely reported as the interference fringe (IF) technique can detect the formation of interference fringe between the reflection from the center convex profile and the reflection from the edge concave profile on the far-field screen. Unlike general microscopy techniques, TIF can detect far-field interference fringes as it focuses beyond the droplet-substrate interface. The formation of the convex-concave profile during CCR evaporation is believed to be influenced by the non-uniform evaporative flux along the droplet surface.

Cephalometric analysis of Indian races: A systematic review

This study is intended to review the cephalometric data pertaining to the diverse Indian populace through a systematic literature survey. To conduct a systematic review of literature, an electronic search was done on Medline, Embase, and Central databases. The available data were categorized based on the existing five geographic locations of the country (north, south, east, west, and central India) and analyzed. The following inclusion criteria were considered: (1) studies depicting the cephalometric data of any ethnic group identified as belonging to India, (2) studies originating from the Indian subcontinent, (3) studies which included data of subjects’ gender separately, (4) studies which compared the cephalometric data of the Indian population with the that of the Caucasians using Burstone and Legan analysis alone, and (5) articles in English language only. The following exclusion criteria were considered: (1) studies conducted on participants with developmental craniofacial anomalies, post traumatic facial deformities or with a history of previous orthognathic surgery, (2) studies which used analysis other than Burstone and Legan for obtaining the data, (3) editorials, commentaries, case reports, systematic reviews, meta-analyses, and articles not available in English language. Seventeen articles met the inclusion criteria. The Indian population showed greater cranial base dimensions than the Caucasians. In the horizontal dimension, the Indian population exhibited a more convex profile with prognathic maxilla, mandible, and chin along with more protrusive upper and lower incisors. However, in the vertical dimension, they exhibited a decreased middle third facial height as well as a decreased ramal and corpus length of the mandible when compared with the Caucasians. The posterior maxillary height and the posterior facial divergence were relatively less in the Indian population when compared with the Caucasians. Sexual dimorphism was noted among the Indian population with regard to a few vertical skeletal parameters which were significantly greater in males than in females. It was observed that the data pertaining to the cephalometric norms on Indian populace in comparison with the Caucasian race are scanty. Compared to the other geographic locations of India, very less literature is available pertaining to the cephalometric data of the Eastern Indian population. It was observed that very less data are available pertaining to the cephalometric norms for the Indian population considering the ethnic, racial, and geographic diversity. The low sample size, studies being restricted to a specific race, or the lack of comparative studies largely impacts the reliability of the available cephalometric data on the Indian population. Considering the fact that the prevalence of dentofacial deformities in India is high, there is a huge ambit for corrective jaw surgery. Hence, it is essential to compile cephalometric data for the Indian populace to establish ethnic and racial-based cephalometric norms.

Research on Effect of Endwall Contouring of Vaned Diffuser on Stable Operating Range of Centrifugal Compressor

Abstract The study investigates the impact of diverse endwall contouring strategies on the operational stability of a high-pressure ratio centrifugal compressor stage. Employing numerical simulation techniques, this study examines the implications of contoured wall positions, specifically convex profiles at the pressure side and/or concave profiles at the suction side, as well as asymmetric endwall contouring, on both stage performance and internal flow field within the centrifugal compressor. And the stability enhancement mechanism of endwall contouring is clarified. The results demonstrate that employing full circular contoured vaned diffusers on the hub-side wall can achieve a maximum improvement in stall margin of 15.10%. Additionally, the diffuser featuring solely convex profiles at the pressure side on the hub-side wall exhibits an augmented stall margin by 8.39%, with a reduction in performance loss at low flow rate conditions. The asymmetric endwall contouring improves stall margin by 8.39%, and mitigates the performance loss across the entire operating range. At the near-stall point, the contoured endwalls redirect fluid towards the suction side, thereby mitigating the incidence at the vane leading edge and attenuating the interaction between the impeller trailing edge vortex and the diffuser leading edge vortex. Moreover, concave profiles serve to accelerate the fluid on the suction side along the flow direction, thereby suppressing the corner separation and weakening passage blockages. Simultaneously, the advantages of endwall contouring in vane diffusers extend to the improvement in the circumferential non-uniformity of flow fields and the enhancement in diffuser stability.

Investigation of vaned diffuser endwall contouring technology for improving the stable operating range of a centrifugal compressor with an asymmetric volute

AbstractIn this study, nonaxisymmetric endwall contouring technology is employed as a passive control strategy to enhance the stable operating range of a centrifugal compressor with an asymmetric volute. The endwall contouring method is applied to the hub‐side wall of the vaned diffuser within a centrifugal compressor stage. Instead of utilizing a flat hub as the baseline diffuser, various diffuser configurations featuring hub‐side contoured endwalls are explored, with adjustments in the peak radial position and peak height of the convex and concave profiles. Numerical simulations are conducted to evaluate the performance of the centrifugal compressor stage with both the baseline and contoured vaned diffusers. The investigation explores the underlying flow control mechanisms and establishes the effective endwall contouring guidelines. The findings highlight the effectiveness of endwall contouring in enhancing the stable operating range of centrifugal compressors. Notably, a substantial enhancement of 15.1% in the stable operating range is achieved by employing the contoured diffuser with the peak radial position near the vane leading edge (LE) and the peak height at 20% of the vane height. The endwall contoured diffusers reduce the positive LE incidence angles to direct the fluid toward the suction side (SS), and increase the radial velocity near the SS to suppress the hub‐suction corner separations in the diffuser passages near the volute tongue. These improvements collectively contribute to the enhancement of diffuser flow characteristics. Finally, a set of effective endwall contouring guidelines is proposed to guide the endwall contouring design for enhancing the stable operating range of centrifugal compressors.

Network analysis of three-dimensional hard-soft tissue relationships in the lower 1/3 of the face: skeletal Class I-normodivergent malocclusion versus Class II-hyperdivergent malocclusion

BackgroundThe determining effect of facial hard tissues on soft tissue morphology in orthodontic patients has yet to be explained. The aim of this study was to clarify the hard-soft tissue relationships of the lower 1/3 of the face in skeletal Class II-hyperdivergent patients compared with those in Class I-normodivergent patients using network analysis.MethodsFifty-two adult patients (42 females, 10 males; age, 26.58 ± 5.80 years) were divided into two groups: Group 1, 25 subjects, skeletal Class I normodivergent pattern with straight profile; Group 2, 27 subjects, skeletal Class II hyperdivergent pattern with convex profile. Pretreatment cone-beam computed tomography and three-dimensional facial scans were taken and superimposed, on which landmarks were identified manually, and their coordinate values were used for network analysis.Results(1) In sagittal direction, Group 2 correlations were generally weaker than Group 1. In both the vertical and sagittal directions of Group 1, the most influential hard tissue landmarks to soft tissues were located between the level of cemento-enamel junction of upper teeth and root apex of lower teeth. In Group 2, the hard tissue landmarks with the greatest influence in vertical direction were distributed more forward and downward than in Group 1. (2) In Group 1, all the correlations for vertical-hard tissue to sagittal-soft tissue position and sagittal-hard tissue to vertical-soft tissue position were positive. However, Group 2 correlations between vertical-hard tissue and sagittal-soft tissue positions were mostly negative. Between sagittal-hard tissue and vertical-soft tissue positions, Group 2 correlations were negative for mandible, and were positive for maxilla and teeth.ConclusionCompared with Class I normodivergent patients with straight profile, Class II hyperdivergent patients with convex profile had more variations in soft tissue morphology in sagittal direction. In vertical direction, the most relevant hard tissue landmarks on which soft tissue predictions should be based were distributed more forward and downward in Class II hyperdivergent patients with convex profile. Class II hyperdivergent pattern with convex profile was an imbalanced phenotype concerning sagittal and vertical positions of maxillofacial hard and soft tissues.

A Novel Interdisciplinary Approach for the Management of Micrognathia (Brodie Syndrome).

This study describes a multidisciplinary approach for correcting a severe Class II malocclusion with reduced mandibular transverse dimension. A 35-year-old woman presented with an increased overjet, complaining chiefly of forwardly placed upper front teeth and unpleasant smile esthetics. The patient had a convex profile with severe mentalis strain on lip closure. Intraoral examination indicated a bilateral Class II canine relationship, scissor bite, and narrow lower arch. The skull lateral view assessment revealed a skeletal Class II relationship with reduced lower facial height. According to the diagnostic records and after consultation with the patient, surgically assisted expansion of the mandibular symphysis with a bone distractor, comprehensive orthodontic treatment, and combined jaw surgery were planned, followed by dental implant placement and prosthetic full-mouth rehabilitation. Restorative dentistry, orthodontics, and orthognathic surgery were the 3 disciplines that helped in achieving the best esthetic and functional results in this patient.

3D surface defect map for assessing buccolingual profile of single tooth gaps following alveolar ridge preservation.

A new, non-invasive approach suggests using single intraoral optical scanning to analyze the ridge profile of single-tooth gaps following alveolar ridge preservation in the absence of a baseline scan. This method involves creating a three-dimensional (3D) surface map to identify and assess contour changes and ridge profiles based on the adjacent teeth. The present study was designed as a cross-sectional pilot analysis on a convenience sample of patients undergoing alveolar ridge preservation. Intraoral optical scans were taken on 23 patients, capturing data from 30 edentulous sites. The digital models were then imported into an image analysis software for a 3D surface defect map analysis performed by one examiner. This analysis characterized the buccolingual profile of the single tooth gap relative to the adjacent teeth. 10 linear divergence points, spaced 0.5 mm apart in a corona-apical direction, were identified at the midfacial aspect of the sites. Based on these points the sites were plotted and grouped in three different buccolingual profiles (linear, concave, and convex). Clinical parameters including Keratinized mucosa Width (KMW), and soft tissue phenotype with Colorvue biotype probes were also recorded. Three different buccolingual patterns (linear, convex, and concave) were identified. Seven sites exhibited a linear profile, 10 sites displayed a concave shape, and 13 showed a convex profile. The linear profile had surface discrepancies similar to the neighboring teeth. In contrast, the convex profile revealed mid-buccal discrepancy localized only at the crestal aspect, while the concave had an extended divergence ranging from 1 to 5 mm below the soft tissue margin. Univariate and multiple logistic regression analyses did not reveal any statistically significant variables influencing profilometric analysis; however, when combining phenotype and KMW, thick phenotypes demonstrated a higher proportion of concavity (OR = 4.83) compared to thin ones, suggesting a significant trend. With every 1 mm of increase in KMW, the probability of showing a concavity decreased (p = 0.057). A 3D surface defect map represents a useful tool for objectively quantifying ridge defects and profiles by assessing profilometric and surface differences compared to adjacent dentition using a single intraoral scan. This method also indicates that KMW may play a critical role in preventing concavity defects. The 3D defect map can guide decision-making during soft tissue augmentation procedures by emphasizing the specific location of the defect and providing more detailed insights into its localization. These parameters can enable the tailoring of flap management and soft tissue grafting strategies to address the patient's individual needs.

Systemic sequelae and craniofacial development in survivors of pediatric rhabdomyosarcoma

IntroductionThe aim of this study was to evaluate the systemic sequelae, as well as the dental and craniofacial development, of patients with rhabdomyosarcoma in relation to the treatment received and clinical-pathological variables. Materials and MethodsA retrospective cross-sectional study was performed. All individuals diagnosed with RMS between 1990 and 2022 were considered eligible. Cases who survived the primary tumor were included. Data were collected from medical records, and patients were called for clinical and radiographic examinations. ResultsThirty-eight patients were assessed, with a mean disease-free survival of 216.68 months (±84.99). The primary location of the tumor was mainly the head and neck region (57.9 %). All patients received chemotherapy, and 30 (78.9 %) also underwent radiotherapy. The most frequently observed sequela was sensory impairment, which was significantly associated with tumors in the head and neck (p < 0.05), as well as with the use of radiotherapy (p = 0.034). Root formation failure was observed in 60 % of cases, microdontia in 50 %, and delayed tooth eruption in 40 %. A convex profile was predominant (80 %), along with maxillary (50 %) and mandibular (80 %) retrusion and a skeletal class II diagnosis (60 %). ConclusionsLate systemic, dental, and craniofacial developmental sequelae are observed in pediatric rhabdomyosarcoma survivors, especially in patients who underwent radiotherapy in the head and neck region. Younger individuals at the time of treatment are at greater risk of late sequelae.

Trajectory control strategy for multi-tool synchronous electrochemical machining of blisk channels

The blisk is a core component of an aero-engine, and electrochemical machining (ECM) is the primary method for its manufacture. Among several ECM methods for blisks, multi-tool synchronous machining is the most efficient and advantageous for machining channels. The allowance distribution of the blank after blisk channel machining directly influences the blade profile accuracy. This paper proposes a trajectory control strategy to homogenize the allowance distribution of the blisk channel in multi-tool ECM. The strategy includes the design of the three-dimensional space motion of the tool and blisk, as well as the regulated feed speed. The structural characteristics of the blisk channel and the principle of ECM allow for designing and optimizing the multi-dimensional trajectory. The electric field simulations elucidate the influence law of the three-axis feed speed on the side gap. An algorithm is adopted to iteratively optimize the speeds for different positions to realize multi-dimensional motion control and allowance homogenization. The proposed trajectory control strategy is applied to ECM experiments for the blisk channel. Compared with the constant feed speed mode, the regulated speed strategy reduces the maximum allowance difference between the convex (CV) profiles by 36.18% and that between the concave (CC) profiles by 37.73%. Subsequently, the one-time ECM of eight blisk channels was successfully realized. The average time for a single channel was 12.5 min, significantly improving the machining efficiency. In conclusion, the proposed method is effective and can be extended for synchronously machining various blisk types with twisted channels.

A Comparison of Esthetic Preferences on Female Skeletal Class II Alterations among Laypeople of Different Facial Profiles.

This study aimed to investigate the influences of assessors' different personal profiles on the esthetic perception of Class II facial profile corrections and the agreement between profile and silhouette images. A profile photo of a female with skeletal Class II was digitally altered into three profile and three silhouette images (most pronounced Class II division 1 characteristic, more retruded upper lip position, and more protruded mandibular position). Ninety-six laypeople from three facial profile groups (straight, convex, and concave profiles) chose these images for facial attractiveness. Data were analyzed using an SPSS program. Cohen's kappa coefficient and intraclass correlation coefficients were applied to determine intraparticipant and intra-examiner reliabilities. Chi-square tests were used to test between-group preferences and the relationship of profile preference with other factors. Cohen's kappa coefficient was used to test the agreement in selecting profile and silhouette images (p = 0.05). All groups favored profiles with a protruded mandibular position (11-degree facial contour angle [FCA] and 91-degree nasolabial angle [NLA]). Despite facial profile differences, preference remained consistent (p = 0.649). The convex group showed a stronger inclination toward an untreated-simulating profile (17-degree FCA and 91-degree NLA). Preferences were consistent regardless of sex (p = 0.198) and education (p = 0.105). The percentage of agreement between profile and silhouette images in the total sample was 67.71% (kappa = 0.386). All groups of participants chose the more retruded upper lip position (17-degree FCA and 107-degree NLA) profile in silhouette more than in photograph. All groups preferred a mandibular advancement-simulating profile. Using the photographs or silhouettes to assess the esthetic preference resulted in a similar trend. However, the flatter profile was more preferred in silhouette than in photograph.

Self-perception and self-recognition of facial profiles in adolescents referred to orthodontic treatment.

To investigate self-recognition and self-perception among participants with straight, convex, and concave profiles. This cross-sectional study was conducted using a questionnaire with questions about demographic information, self-perception of the facial profile, satisfaction with profile esthetics, expectations about profile changes after completing orthodontic treatment, motivational factors, and self-recognition. For the self-recognition question, profiles of the respondents were blackened and inserted into the questionnaire. Participants were categorized into three groups: those exhibiting a convex, straight, and concave profile. There was no statistically significant difference between the straight, concave, and convex profile groups regarding self-recognition and self-perception. Participants showed greater ability in self-recognition than self-perception of their soft-tissue profile (P = .001). Females showed higher capability in self-perception than males (P = .001). Self-recognition and self-perception of the soft-tissue profile are not influenced by facial convexity.

Application of lubrication theory to determine yield stress in slump tests

The slump test can determine the yield stress of slurries by measuring the slump height. The convex shape in the slumped slurry profile cannot be characterised by the Tresca criterion. Lubrication theory has been widely applied to analyse the slow flow of yield stress fluids. Thus, the present study incorporates lubrication theory and the Tresca criterion to establish a generalized model for reconstructing the slurry profile based on the yield stress. The convex profile in the lower zone can be well represented by the novel method. The predicted yield stresses by the slump tests are larger than those determined using the vane method. Slump height and spread are equally accurate for predicting yield stress via the proposed method. Overall, the combination of lubrication theory and Tresca criterion yields a good prediction of yield stress based on slump height.

Establishment of Cephalometric Hard Tissue Profile among Bengali and Caucasian Populations for Orthognathic Surgery

ABSTRACT The study aimed to compare cephalometric hard tissue profile values and analysis between Bengali and Caucasian populations. The study included 100 individuals (50 males, 50 females) aged 18–35. Subjects having class I molar occlusions and well-balanced facial profiles were included in the study. Lateral cephalograms were taken with consent, and a prestructured proforma recorded relevant information and cephalometric measurements. Our study found increased posterior cranial base length in Bengali males and increased anterior cranial base length in both sexes. Bengali males had a less convex profile, while females had a more convex profile compared to Caucasians with similar mandibular features. Increased maxillary and mandibular incisor proclination was observed. Our findings indicate the necessity for separate norms for orthognathic surgery in normal ethnic Bengali adults.

Effects of longitudinal profile shape on scour and flow resistance in rills

AbstractThe literature regarding how rill longitudinal profile (concave and convex) affects soil loss and flow resistance is still lacking. The only analysis available in the literature for rills is limited by the fact that measurements were performed for a unique mean slope value sp (18%). In this article, further rill measurements were conducted on a plot with sp = 15% and complex profile shapes and were used to widen the knowledge about the influence of longitudinal profile shape on rill scour, eroded volume, and flow resistance. The findings highlighted that the concave profile has a homogeneous spatial distribution of moderate scours, whereas the scours in the convex one are deeper and more confined, but they are not placed after the slope change as found for sp = 18%. The mean scour depth, which accounts for the discharge and profile shape effects, is not (concave) or is weakly (convex) related to the flow discharge. The concave profile determined a reduction of approximately 57% of the total eroded volume when compared with the convex profile shape, confirming that a concave hillslope limits erosive phenomena. Finally, the flow resistance equation guaranteed a precise estimation of the Darcy–Weisbach friction factor.

Investigating the origin of the far-field reflection interference fringe (RIF) of microdroplets

We show that the reflection interference fringe (RIF) is formed on a screen far away from the microdroplets placed on a prism-based substrate, which have low contact angles and thin droplet heights, caused by the dual convex–concave profile of the droplet, not a pure convex profile. The geometric formulation shows that the interference fringes are caused by the optical path difference when the reflected rays from the upper convex profile at the droplet–air interface interfere with reflection from the lower concave profile at oblique angles lower than the critical angle. Analytic solutions are obtained for the droplet height and the contact angle out of the fringe number and the fringe radius in RIF from the geometric formulation. Furthermore, the ray tracing simulation is conducted using the custom-designed code. The geometric formulation and the ray tracing show excellent agreement with the experimental observation in the relation between the droplet height and the fringe number and the relation between the contact angle and the fringe radius. This study is remarkable as the droplet's dual profile cannot be easily observed with the existing techniques. However, the RIF technique can effectively verify the existence of a dual profile of the microdroplets in a simple setup. In this work, the RIF technique is successfully developed as a new optical diagnostic technique to determine the microdroplet features, such as the dual profile, the height, the contact angle, the inflection point, and the precursor film thickness, by simply measuring the RIF patterns on the far-field screen.

The geomorphometric atlas of Romania: an open-access database on landform classifications and morphometric variables

ABSTRACT This paper presents the first digital geomorphometric atlas of Romania. It primarily includes existing international classifications of landforms, as well as land-surface variables (LSVs) derived from Forest and Buildings removed Copernicus Digital Elevation Model (FABDEM) at a resolution of 30 m. Besides the standard moving window of 3 × 3 (90 × 90 m), most LSVs were also derived in moving windows of 11 × 11 (330 × 330 m), and 27 × 27 (810 × 810 m), which represent the topographic grain values specific to the Romanian topography. Up to this point, the atlas contains 10 sets of landform classification data including the geomorphons and 24 sets of LSVs as follows: Slope, Aspect, Sin (Eastness), Cos (Northness), Profile Convexity, Plan Convexity, Longitudinal Curvature, Cross-Sectional Curvature, Minimum Profile Convexity and Multidirectional Hillshade. The data are available open-source for both interactive visualizations on the ArcGIS Online platform and for download on the Google Drive platform.

Effects of two-phase treatment with functional appliances versus one-phase treatment with pre-molar extraction in Class II div 1 monozygotic twins: A case study

The aim of the study was to compare the skeletal, dental, or soft-tissue outcomes of a one-phase camouflage treatment with pre-molar extraction versus a two-phase treatment with combined twin-block high-pull headgear followed by fixed orthodontic treatment in monozygotic twins. 12-year-old male monozygotic twins presented to the dental clinic with complaints about their anterior teeth. Cephalometric analysis of the patients revealed skeletal Class II malocclusion and a long facial type. Extraoral examination of the patients revealed incompetence of lip seal and a convex profile. In Patient 1, the use of a high pull headgear combined with a twin block to correct skeletal anteroposterior and vertical malocclusions with growth modification and then fixed orthodontic treatment was planned. Patient 2 did not comply with the treatment, complaining that the use of the device could cause esthetic problems and difficulties in use. Therefore, camouflage treatment with extraction of four pre-molars was planned as another treatment option for Class II patients in Patient 2. With the camouflage treatment, the patient continued to grow normally. The combined treatment with twin block and a high pull occipital headgear resulted in inhibition of maxillary growth and a reduction in the severity of the skeletal Class II malocclusion, but the mandibular changes were similar in both patients at the end of treatment. Despite the different treatment modalities, both twins achieved a Class I canine-molar relationship and ideal overjet and overbite. Patients can close their lips with improved soft-tissue profiles. The criteria for the choice of treatment depend entirely on the requirements of the patient.