Convex Profile Research Articles

Effects of laterality on esthetic preferences of orthodontists, maxillofacial surgeons, and laypeople regarding the lip position and facial convexity: a psychometric clinical trial.

There are few, controversial, and limited studies on factors associated with the perception of profile beauty. Moreover, no study has ever assessed the role of laterality in esthetic judgment. Hence, this clinical trial was conducted. Photographs of 6 patients (3 women) with normal lip position (Ricketts norm = 0mm) and facial convexity (Legan-Burstone norm = 12°) were digitally manipulated to create two series of 9 gradient images each, with convexity changes of 2° and anteroposterior lip modifications of 1mm. Half of profiles were flipped horizontally. Laypeople (n = 35), orthodontists (n = 19), and maxillofacial surgeons (n = 10) selected the esthetically acceptable images (6912 esthetic evaluations [2 parameters × 6 sets × 9 images × 64 judges]). Effects of photogrammetric stimuli and other factors on judges' zone of esthetical acceptability (ZA) and its midrange were assessed statistically (α = 0.05). Orthodontists and surgeons had respectively the broadest and narrowest ZAs (p < 0.05, ANOVA). Mean midranges of surgeons, orthodontists, and laypeople were respectively 0.27 ± 1.35, 0.56 ± 1.46, and 0.41 ± 1.77mm for males' lower lips (p = 0.710, ANOVA); 0.27 ± 1.10, - 0.44 ± 0.91, and 0.03 ± 1.56mm for females' lower lips (p = 0.034); 10.40 ± 3.17°, 11.09 ± 2.86°, and 11.57 ± 3.84° for men's profile convexity (p = 0.246); 10.27 ± 3.20°, 11.05 ± 1.87°, and 11.13 ± 3.26° for women's profile convexity (p = 0.346). Judges' gender did not affect their esthetic perception (p > 0.1). When patients' left side of face was visible, judges' esthetic preference parameters shifted towards a less convex profile and a narrower ZA (p < 0.05). Slightly protruded lips (for men) and slightly less convex profiles (for men/women) might be favored by all groups. Women's esthetic lip positions might differ among groups. Judges' gender might not be a determinant. Subjects' face side can influence judges' esthetic perception of facial convexity.

The impact of oral appliance therapy with moderate mandibular advancement on obstructive sleep apnea and upper airway volume

PurposeTo find out if a moderate protrusion with a mandibular advancement device (MAD) can significantly increase the upper airway volume and, further, what signs and symptoms of obstructive sleep apnea (OSA) can be improved by this maneuver.MethodsThere were 58 adults diagnosed with OSA who were referred for MAD therapy. The mean apnea-hypopnea index (AHI) was 19.2 (SD 8.6). Five indicators of signs and symptoms of OSA (AHI, oxygen saturation, snoring, daytime sleepiness, and health-related quality of life) were evaluated at the baseline and after 6 months of MAD therapy. Nasal resistance and airway volume and cross-sectional areas with and without the MAD in situ were recorded. Based on AHI reduction, the treatment response was classified as complete, partial, or non-complete. Statistical analyses included the chi-square, t tests, Mann–Whitney U tests, and regression analyses (linear and logistic).ResultsTwenty-three patients attained a complete response (residual AHI < 5 events/h) to MAD therapy. In 13 subjects, the response was partial, and in 9 patients, it was non-complete. The complete responders were significantly younger, and they had a deeper overbite than partial/non-complete responders. A convex profile associated positively, but a vertically restricted throat and increased lower facial height associated negatively with the increase in airway volume.ConclusionsExcellent MAD therapy outcomes were achieved in most patients. Only age and deep bite had some influence on AHI reduction, indicating multifactorial nature in the response to MAD therapy.

On the performance limits of coatings for gravitational wave detectors made of alternating layers of two materials

The coating design for mirrors used in interferometric detectors of gravitational waves currently consists of stacks of two alternating dielectric materials with different refractive indexes. In order to explore the performance limits of such coatings, we have formulated and solved the design problem as a multiobjective optimization problem consisting in the minimization of both coating transmittance and thermal noise. An algorithm of global optimization (Borg MOEA) has been used without any a priori assumption on the number and thicknesses of the layers in the coating. The algorithm yields a Pareto tradeoff boundary exhibiting a continuous, decreasing and non convex (bump-like) profile, bounded from below by an exponential curve which can be written in explicit closed form in the transmittance-noise plane. The lower bound curve has the same expression of the relation between transmittance and noise for the quarter wavelength design where the noise coefficient of the high refractive index material assumes a smaller equivalent value. An application of this result allowing to reduce the computational burden of the search procedure is reported and discussed.

Validated Assessment Scales for the Female Asian Calf.

Clinical photonumeric scales have been developed and validated to objectively measure the effectiveness of aesthetic treatments in specific anatomical areas; however, these are based on the typical features of Caucasian patients. No clinical scale for Asian calf appearance currently exists. To develop and validate a calf assessment scale for use in the female Asian patient population. During 2 validation sessions, 13 raters assessed calf images of female Asian subjects (N = 35) viewed from behind with feet flat on the floor (at rest) and on tiptoes (dynamic). Images were rated from 0 (very slim, linear profile) to 4 (very severe convex profile). Inter-rater and intra-rater reliability were "substantial" (≥0.6, intraclass correlation coefficient [ICC] and weighted kappa) for the calf-at rest, calf-dynamic, and calf summary score. Reliability was "substantial" for calf-at rest and calf-dynamic (≥0.6, ICC and weighted kappa) and "almost perfect" (0.85) for the calf summary score. BMI and calf circumference were highly correlated with scale ratings, and calf circumference was a significant predictor. This new photonumeric assessment scale has value for assessing the female Asian calf, providing a standardized measure of calf appearance in clinical practice and clinical research settings.

Esthetic perception of facial profile contour in patients with different facial profiles

BackgroundPatients' perception is crucial for developing a treatment plan, one factor being facial profile. The aim of this study was to evaluate the influence of an individual's facial profile on his or her perception of attractiveness of another's facial profile. Materials and methodsPhotographs of one male and one female individual were modified by altering the facial contour angle (FCA) in 4° increments and shown to a group of 153 orthodontic patients divided into three groups (n = 51): Convex, FCA >13°, Straight, FCA 5°–13°, and Concave, FCA <5°, who scored the attractiveness of each image using a visual analog scale. ResultsAll groups considered a normal or slightly convex profile as the most attractive, and an extremely concave profile as the least attractive. For male images, there was no significant difference between groups, except for the extremely convex profile, which was preferred by the convex group compared with the concave group. For female images, no significant difference was found between groups, except for the slightly convex profile. The concave group rated this profile higher compared with the convex group. Comparing within each group demonstrated that there were no significant differences between the slightly convex and the normal subgroups, as well as the extremely convex and the slightly concave subgroups, among the three groups. ConclusionsAll groups shared similar perception. The most and least attractive profiles were the normal and extremely concave profiles, respectively. Slightly convex profiles were recognized as attractive as normal profiles, whereas slightly concave and extremely convex profiles were equally unattractive.

Reconfigurable RF Dispersive Delay Circuits by Stepped Impedance Shunt Stubs

A design of RF dispersive delay circuits with both convex and concave delay profiles using stepped impedance stubs are presented in this brief. A transmission line model is used to analyze the structure and to obtain design equations. Three prototypes with different delay profiles are fabricated to validate the proposed technique. Next, a reconfigurable delay line with switchable delay profiles is presented. However, because of its parasitic, PIN diodes used for switching change the delay profile. A procedure is described to compensate the loading effect of PIN diodes. A prototype is fabricated. In all the cases, good agreement is obtained among the predicted and measured results. A comparison with recent works shows that present unit provides highest peak group delay with minimum insertion loss. The dispersive delay lines operate as a linear device at least up to 23 dBm of input power.

Indian Board of Orthodontics Case Report: Management of a Skeletal Cl II Malocclusion Using Two-phase Treatment with a Standard Twin Block Appliance

NK, a 12-year-old male patient, presented with a Class II division 1 incisor relation on a Class II skeletal base with a decreased maxillomandibular plane angle and decreased face-height ratio. He had a convex profile, incompetent lips, lip trap, deep mentolabial sulcus, everted lower lip and a positive VTO (Visual Treatment Objective). Intraorally, he presented with bilaterally Angle’s Class II molar relation and canine relation, scissor bite in the region of first premolars bilaterally, a closed bite and a 13 mm overjet. He presented with mild spacing in the upper arch and mild crowding in the lower arch with a pronounced curve of Spee. This was further complicated as the LR6 was endodontically treated and temporarily restored; also, enamel hypoplasia was seen in all permanent first molar region. The treatment was carried out in two phases, Phase I involved growth modulation done with a twin block appliance, and Phase II was the postfunctional orthodontic phase for dental corrections and finishing and detailing of occlusion, which was done with a preadjusted edgewise appliance (0.022 × 0.028˝ slot) with MBT (McLaughlin, Bennett, Trevisi) prescription. The posttreatment results were highly satisfactory, showing improvement in facial esthetics and occlusal traits as well as good long-term stability as was evident in the 3-year retention records.

DIFFERENCE IN CRANIOFACIAL CHARACTERISTICS IN ATTRACTIVE MALE AND FEMALE FACES

Beauty, or more precisely, the art that is hidden in the creation of human face has always attracted great interest and has been a research point in many areas. Contemporary orthodontic is science which is trying to stady human face throught mesurable and objective parameters. Since ancient cultures and societies, huge attention has been focused on facial aesthetics and phisical atractivness. Today, phisical atractivness in both male and female continues to be much more highlited and the interest for facial aesthetics is growing.The aim of this study is to determine the influence of the gender on skeleton-facial characteristics(Sagittal jaw relationship, vertical jaw relationship and profile convexity) between attractive male and female faces. The study was performed on 54 attractive individuals (18 males and 36 females) ranging in age between 14-25 years. Facial attractiveness was assessed by using an-face photographs examined by a panel of 50 students. For ranking facial attractiveness VAS-Visual Analog Scale was used. Craniofacial morphology was determined by using lateral head film. Cephalometric analyses included measuring of sagittal jaw relationship, vertical jaw relationship and profile convexity. The data obtained from cephalometric analyses were compared between the two groups. Results in this study reveals that when comparing attractive males with attractive females, the attractive Macedonian males had larger SNB angle(p&lt;0.001) and SNPg (p&lt;0.05), or more precisely anterior positioned mandible with prominence of the chin. There was statistically significant difference for the angle ANB(P&lt;0.001) i Wits(p&lt;0.01) confirming the presence of biger profile convexity (NSPg p&lt;0.001 i NsSnPgs p&lt;0.001) in attractive female individuals that shows the existance of the sex dimorphism. Based on our findings we can concluded that more flat profiles are preferred today, actually perception of an ideal male profile in modern times is flat profile with smaller dominance of the nose and more convex profiles in attractive female faces

Morphological variation of star dune and implications for dune management: a case study at the Crescent Moon Spring scenic spot of Dunhuang, China

Aerial photographs and 3-D laser scans of a 90-m high star dune at the Crescent Moon Spring scenic spot in Dunhuang, China, are used to investigate the changes in dune morphology on timescales from months to decades. The result revealed that relative-equilibrium airflow strength in three wind directions of northeast, west and south was an important condition for the stability of star dunes with limited migration. Transverse and longitudinal airflows exerted a crucial impact on variation processes of star dune morphology. Controlled by transverse airflows, the easterly winds, the east side was dominated by wind erosion; and strong deposition occurred on the south-south-east arm with a maximum deposition rate of 0.44 m/a in the 46-a monitoring period, causing the east side becoming steep and high. Controlled by longitudinal airflows, the westerly winds, the west-north-west side was mainly eroded and the north arm migrated from west to east with a rate of 0.30 m/a, causing the dune slope becoming gentle and elongate. The local air circulation (southerly winds) exerted a significant impact on the development process of the star dune. Due to the influence of human activities, the south side present surface processes from a concave profile to a convex profile in 46 a, which is a potential threat to the Crescent Moon Spring. The results indicate that rehabilitating the airflow field at most is a crucial strategy to the protection of Crescent Moon Spring from burial. Opening up the passage of easterly, westerly and southerly winds through intermediately cutting the protection forest, demolishing the enclosed wall and changing the pavilion into a porous pattern have been suggested to protect the Crescent Moon Spring from burial.

The links between entrance geometry, hypsometry and hydrodynamics in shallow tidally dominated basins

AbstractGeomorphological characteristics of tidal basins control hydrodynamics and sediment transport potential within such basins, for example, by adjusting the balance in tidal asymmetry. In this study we examine the effects of entrance geometry on tidal velocity asymmetry, slack water asymmetry, bed shear stress patterns and hypsometric profile shapes by comparison of six shallow meso‐tidal basins of Tauranga Harbour, New Zealand. Numerical model results show how tidal distortion increases with distance from a basin entrance. A simple ratio between basin width and entrance width defines levels of basin dilation. Sub‐basins with a constricted geometry and deep entrance channels are associated with small bed shear stress values and high rates of flood‐directed tidal velocity asymmetry in the sheltered basin centres, indicating a large potential for sediment deposition of larger particles. Moreover, slack water asymmetry within these basins is weakly ebb‐directed, indicating a small potential for transport of fine sediments out of the basins. The constricted depositional basins are characterized by convex hypsometric profiles with elevated intertidal regions. Unconstricted geometries are associated with larger bed shear stress values and more ebb‐directed tidal velocity asymmetry within basin centres, suggesting limited potential for overall sediment deposition. The slack tide duration asymmetry is weakly flood‐dominant indicating that limited input of fine sediment into the basins is possible. The comparatively high‐energy conditions within these exposed basins are associated with a less convex hypsometric intertidal profile. The ability to estimate tidal asymmetries is advantageous when developing management strategies related to ecosystem functioning, navigability or coastal protection in specific geomorphic settings. © 2019 John Wiley &amp; Sons, Ltd.

Profile Design for Misaligned Journal Bearings Subjected to Transient Mixed Lubrication

Misalignment between the shaft and the bearing of a journal bearing set may be inevitable and can negatively impact journal bearing performance metrics in many industrial applications. This work proposes a convex profile design of the journal surface to help counteract the negative effects caused by such a misalignment. A transient mass-conserving hydrodynamic Reynolds equation model with the Patir–Cheng flow factors and the Greenwood–Tripp pressure–gap relationship is developed to conduct the design and analysis. The results reveal that under transient impulse loading, a properly designed journal profile can help enhance the minimum film thickness, reduce mean and peak bearing frictions, and increase bearing durability by reducing the asperity-related wear load. The mechanism for the minimum film thickness improvement due to the profile design is traced to the more even distribution of the hydrodynamic pressure toward the axial center of the bearing. The reason for the reductions of the friction and wear load is identified to be the decreased asperity contact by changing the lubrication regime from mixed lubrication to nearly hydrodynamic lubrication. Parametric studies and a case study are reported to highlight the key points of the profile design and recommendations for profile height selection are made according to misalignment parameters.

ANALYSIS OF QUALITATY INDICATORS OF NON-EVOLVENT GEARING

The article substantiates the relevance of the study of gears with a complex non-involute profile of the side surfaces of the teeth, which in some applications have advantages over involute gears and are devoid of some of their drawbacks associated with quality indicators. A technique for obtaining mating surfaces of the teeth of non-invasive gears as envelopes of the specified surfaces of the teeth of tools is described. A scheme for forming pairs of non-involute gears, from which a gearing can be composed, is proposed. It is shown that to obtain the mating surfaces of the teeth of two non-involute gears, two tool rails can be used with the profiles of the side surfaces of the teeth opposite to each other. As a nonlinear profile of the tooth lateral surface of the tool rail, some part of one of the simulated flat kinematic curves is considered. A description of the program developed in accordance with the described method is given, which allows you to calculate the geometric characteristics of the shaped profiles of the gear pair wheels, visualize the shaping process, and also determine the quality indicators of the gearing. Thus, the prerequisites were created for choosing from the resulting geometric modeling of the curve field of such tooth profiles of the tools, which would provide the most rational combination of the tooth profiles of the gears processed by them and the required quality parameters of the gear teeth. The results of the study of the pressure ratio between the teeth of a gear and the overlap ratio of gears when choosing the shape of the tooth profiles are presented. A series of numerical experiments for gearing, formed by pairs of tool rails with different profiles of the side surfaces of the teeth - straight, convex and concave, as well as convex-concave were performed. It is shown that non-involute gearing can have large reduced radii of curvature (and consequently smaller pressure coefficients) at the points of tangency of the profiles compared to involute gearing with a slight increase or decrease in the gearing overlap ratio. The most preferable is the variant of the rails with convex and concave tooth profiles, which provides the best values of both quality indicators of the engagement.

Anteroposterior and vertical soft tissue cephalometric norms of Iranians, interethnic comparisons, sex dimorphism, and the effect of age on cephalometric variables.

This study established about 50 anteroposterior and vertical cephalometric norms of five tracing analyses in Iranians, using a large sample. Lateral cephalographs of 130 subjects (85 females, 45 males, with an average age of 22.77 ± 2.55years (range 20-29)) were traced manually using the Ricketts, Holdaway, Z-Merrifield, Epker, and Legan-Burstone soft tissue analyses. The role of age and sex on measurements, as well as the comparisons between Iranian norms with Caucasians from European decent, was determined statistically (α = 0.001). Age had no significant effect (all P values > 0.01). Sexual dimorphism existed in terms of numerous parameters. Compared to analysis standards, upper lip to E-plane, nose prominence, upper lip thickness, nasomental angle, Z angle, interlabial distance, subnasale perp to chin, subnasale-stomion:stomion-menton, subnasale-lower lip:lower lip-menton, interlabial gap, and vertical lip-chin ratio were smaller in Iranians. Superior sulcus depth, skeletal profile convexity, upper lip strain, upper lip curvature, H-angle, soft tissue chin thickness, nasofacial angle, subnasale perp to upper lip, subnasale perp to lower lip, maxillary prognathism, lower face throat angle, upper lip protrusion, lower lip protrusion, mentolabial sulcus, and lower vertical height-depth ratio were greater in Iranians compared to the norm (P ≤ 0.001). A great degree of sex dimorphism might exist among Iranians. Many textbook norms might not be the best options for diagnosis or treatment of Iranians.

Conformal Cassegrain reflecting systems using meta-surfaces

Meta-surfaces have been applied into various conformal reflectors for the design of a Cassegrain system. In particular, we introduce different primary meta-surface reflectors of concave, planar, and convex profiles into the design of a dual reflecting system together with a secondary flat meta-mirror to generate highly directive beams. All these kinds of conformal Cassegrain reflecting systems are shown to possess aperture efficiencies comparable with conventional Cassegrain reflectors. While the concave meta-surface reflector offers the opportunity to build up a more compact system with a much smaller focal length, the planar meta-surface reflector demonstrates the characteristics of a low profile and easy fabrication, and the convex meta-surface reflector enables the whole system to be planted on a curved platform. Subwavelength square ring patches are finally employed to synthesize these reflectors and demonstrate their functionalities of tuning reflecting phases of electromagnetic beams with greatly enhanced radiation, both numerically and experimentally.

Changes in soft tissue facial profile of class II skeletal malocclusion patients with retrognathic mandible treated with twin block appliance

Introduction: The soft tissue aspect in orthodontics treatment has gained attention in the last few years. The soft tissue profile is said to reflect the underlying skeletal profile, which causes a convex profile in patients with class II skeletal malocclusion. This research was aimed to determine the changes in the soft tissue facial profile of class II skeletal malocclusion patients with retrognathic mandible after twin block treatment. Methods: The type of research used in this study was retrospective descriptive research with paired t-test. The population was children aged 10-13 years old with class II skeletal malocclusion that were treated with twin block appliance in the Faculty of Dentistry Universitas Padjadjaran, Indonesia. The results of soft tissue changes before and after twin block treatment were compared. Results: There was an insignificant increase in soft tissue profile angle and Holdaway’s soft tissue angle after twin block treatment (p &gt; 0.05). Whereas, Holdaway’s H-angle was decreasing and Merrifield’s Z-angle was increasing after twin block treatment, with statistically significant difference (p &lt; 0.05). Conclusion: There was a decrease of H-angle, indicates a reduction in facial convexity and improvement of the facial profile after twin block treatment, but no difference in soft tissue profile angle and Holdaway’s soft tissue angle after twin block treatment. Keywords: Facial soft tissue profile, class II skeletal malocclusion, retrognathic mandible, twin block appliance

Orthodontic anterior teeth space closure in an adult with posterior long standing fixed partial denture

This is a case report of a 40-year-old female patient with chief complaint of spacing in front teeth. Patient exhibited convex profile, incompetent lips, spacing in anterior maxillary and mandibular teeth. She had maxillary posterior long span fixed partial denture and generalised periodontitis. She was diagnosed as Class I malocclusion with proclined and spaced anterior teeth. Treatment objective include space closure, maintaining class I molar and canine relation, achieving ideal overjet and overbite and functional occlusion. Thorough oral prophylaxis was done prior to start of fixed mechanotherapy. The case was bonded (upper canine to canine and full lower arch) with 022 MBT bracket system. Aligning and levelling was done sequentially with 012,016,17x25 Niti wires. One bracket each side was bonded on the maxillary FPD abutment teeth for anchorage. Space closure was achieved using low forces with elastomeric chain on 19x25 SS wire. Total treatment time was 12 months. Ideal overjet and overbite achieved with functional occlusion. Periodontal condition improved and stable results were achieved. Patient is given fixed retention and removable hawleys retainer with tongue crib in upper arch. In the recent years, there has been an increase in number of adults seeking orthodontic treatment and orthodontists quiite often face patients with periodontal disease. Adult patients should follow regular oral hygiene measure in order to maintain periodontal health during and after active orthodontic therapy.

Resolved galaxy scaling relations in the eagle simulation: star formation, metallicity, and stellar mass on kpc scales

We explore scaling relations between the physical properties of spatially resolved regions within the galaxies that emerge in the Evolution and Assembly of GaLaxies and their Environments (EAGLE) hydrodynamical, cosmological simulations. Using 1 kpc-scale spaxels, we compute the relationships between the star formation rate and stellar mass surface densities, i.e. the spatially resolved star-forming main sequence (rSFMS), and between the gas metallicity and the stellar mass surface density, i.e. the spatially resolved mass-metallicity relation (rMZR). We compare to observed relations derived from integral field unit surveys and imaging of galaxies. EAGLE reproduces the slope of the local ($z\approx0.1$) rSFMS well, but with a $\approx-0.15$ dex offset, close to that found for the galaxy-integrated relation. The shape of the rMZR agrees reasonably well with observations, replicating the characteristic turnover at high surface density, which we show is due to AGN feedback. The residuals of the rSFMS and rMZR are negatively (positively) correlated at low (high) surface density. The rSFMS becomes shallower as the simulation evolves from $z=2$ to 0.1, a manifestation of inside-out galaxy formation. The shape of the rMZR also exhibits dramatic evolution, from a convex profile at $z=2$ to the observed concave profile at $z=0.1$, such that the gas in regions of high stellar density is more enriched at higher redshift. The redshift independence of the relationship between the galaxy-wide gas fraction and metallicity in EAGLE galaxies is not preserved on 1 kpc scales, implying that chemical evolution is non-local due to the transport of gas and metals within galaxies.

Hobbing Manufacturing of New Type of Involute-Helix Gears for Wind Turbine Gearbox

The involute gears are widely used in the gearbox for wind turbine. To satisfy the requirements of reduction of noise and increase of the endurance of the gear drive, the new type of involute-helix gears, which have the advantages of involute gears and circular arc gears, had been proposed. In this paper, the hobbing cutters of involute-helix gears are designed utilizing the normal section of convex and concave tooth profiles, respectively. Mathematical models of hobbing cutters are established and general products are also manufactured. Using the developed hobbing cutters, the proposed gear pair is manufactured based on the numerical control technology. Combining with the measure method of gear measuring center and the characteristic of the investigated gears, the method of error measurement of special tooth profiles is provided. The further development of special detection software for the gears will be carried out. The results will lay the foundations for the large-scale industrial practice and production applications of gear drive.

Liquid bridges between a sphere and a plane - Classification of meniscus profiles for unknown capillary pressure

The motivation for this study results from the following practical observation: for the experimenter, the value of the capillary pressure is a priori an unknown of the problem, it corresponds to a spontaneous value resulting a posteriori from a static equilibrium. A general classification of axisymmetric capillary bridge profiles for unknown capillary pressure between a sphere and a plane is addressed in this article. The meridian of the liquid bridge is classified into convex or concave profiles as portions of nodoid or unduloid surfaces based on measured geometrical data with special limit cases as catenoid, cylinder, or sphere. The theoretical work is then validated by an image-processing technique applied to images of real capillary bridges from experiments for small water volumes and small sphere–plate separation distances. The laboratory tests show very good agreement between the theoretical calculations and the associated classification proposed. Even the transition case of a catenoid can be observed.

Orthodontic treatment with passive eruption and mesialization of semi-impacted mandibular third molar in an adult with multiple dental losses

ABSTRACTObjective: This article describes the orthodontic treatment performed on an adult patient with multiple dental losses. Case report: A female patient, 20 years and 4 months old, presented with the following conditions: absence of teeth #26, #35, #36 and #46; semi-impacted tooth #48; inclined molars adjacent to an edentulous space; canines and premolars in a Class II relationship; a convex profile; biprotrusion; and forced lip sealing. Results: Space in the region of tooth #26 was closed, as well the space of tooth #46; tooth #48 erupted and followed mesial movement passively; space of the region of tooth #35 was maintained for the placement of a dental implant; uprighting of tooth #37 was obtained. Aesthetic and functional goals of the treatment were achieved. Results remained stable 10 years after the end of the treatment. Conclusion: The modified helical loop could be effectively used in orthodontic mechanics to close edentulous spaces. Passive semi-impacted mandibular third molar eruption and mesialization can occur in adults when proper space is provided.