Soft-tissue profile changes in adult patients treated with premolar extractions.

INTRODUCTION: The objective of this study was to identify the soft-tissue profile changes and the potential pretreatment cephalometric parameters that clinicians could use to predict the lip response after premolar extraction treatment in adult patients. METHODS: Pretreatment and posttreatment lateral cephalograms of 75 white patients treated with premolar extractions were analyzed. The following initial cephalometric measurements were recorded: upper and lower lip to E-plane, vermilion thickness, lip length, maxillary and mandibular incisor inclination, and mentolabial and nasolabial angle. Pretreatment and posttreatment radiographs were superimposed using the Björk structural method to record lip retraction and incisor/lip retraction ratio. Pearson correlation and Kruskal-Wallis tests were used to compare lip retraction and incisor/lip retraction ratio with the cephalometric variables. The sample was divided according to different extraction patterns. RESULTS: The mean upper and lower lip retraction values were 1.4 mm and 1.7 mm, respectively. Vermilion thickness showed a negative and statistically significant correlation (P <0.05) with lip retraction and incisor/lip retraction ratio. In addition, the mean incisor/lip retraction ratio was 61% and 98% for the upper and lower thin lip, respectively, whereas the mean incisor/lip retraction ratio was 17% and 44% for the upper and lower thick lip, respectively. The comparison among extraction patterns did not highlight any noticeable difference. CONCLUSIONS: The choice of a specific extraction pattern did not impact lip response. The vermilion thickness was the key factor influencing lip retraction: an increase in this parameter was related to a decrease in lip retraction and vice versa.

Non-compliance treatment in a young adult full-step class II division 2 malocclusion with preadjusted lingual appliance and upper first molars extractions.

This case report describes a complex full-step class II case in a young adult patient treated with lingual straight-wire appliance and upper first molar extraction. As the patient refused a surgical treatment, she was offered the best possible camouflage with the double aim of obtaining an ideal occlusal relationship and maintaining the profile; appropriate biomechanical strategies, including extraction choice and anchorage control during space closure, were needed to achieve the planned results. This case report demonstrates the possibility of successfully resolving severe sagittal discrepancies in an adult patient without surgical treatment by means of a completely invisible non-compliance technique, with the extraction of the most compromised teeth. This report also underlines the need for careful planning during both diagnostic and treatment phases, in order to obtain the best results.

Evaluation of effects of brackets and orthodontic wires on intraoral scans: A prospective in-vivo study.

OBJECTIVE: To evaluate any distortion produced by multibracket fixed orthodontic appliances on digital models obtained from intraoral scans (IOS), considering the presence of both brackets only and brackets/archwire combination. SETTING/SAMPLE: The IOS data of the arches of 20 patients (12 females and 8 males; mean age = 15.55 ± 2.84 years) were acquired using the CS3600 intraoral scanner (Carestream Dental, Atlanta, USA), without any appliances (model A), with vestibular brackets alone (model B) and then with brackets and orthodontic archwire fitted (model C). MATERIALS AND METHODS: Data were acquired between the months of January and October 2021 at the moment of indirect bonding phase. On each model, five intra-arch linear measurements were obtained (inter-canine, inter-premolar 1 and 2, inter-molar and arch depth), and after digital matching between model A and B (match 1) and A and C (match 2), the linear discrepancies were evaluated at 20 points (10 occlusal and 10 gingivolingual) previous identified on the reference model A. All measurements were performed using Geomagic Control X software (3D Systems, Morrisville, USA), and any dimensional variations and distortions were evaluated by the linear regression analysis and two-sample t-test (P ≤ .05). RESULTS: The results show an almost perfect correlation between both models B and C and the reference model A, both as regards the intra-arch linear measurements and the linear discrepancies found at the 20 identified points. CONCLUSIONS: Multibracket fixed orthodontic appliances do not produce any relevant distortions in digital models obtained via intraoral scanning. Therefore, the removal of archwire is not mandatory before IOS.

Invisible treatment with lingual appliance for the correction of an adult class II subdivision with asymmetrical Wilson and Spee curves: A case report.

This article describes a class II subdivision malocclusion successfully treated by an invisible lingual appliance. The combination of en-masse distalization by interradicular palatal mini-screws and inner unilateral class II auxiliaries, first by intermaxillary elastic, later by a class II coil spring, resulted in a dento-alveolar correction, allowing one to maintain the appliance completely invisible. At the same time, the inclination of buccal sectors was normalized by a correct torque expression with set-up overcorrections, resulting in a significant improvement of the buccal corridors. This case report demonstrates the possibility of successfully solving class II division 2 subdivision malocclusion in adult patients without surgery by means of a completely invisible appliance. It also demonstrates that correct levelling and torque expression, for the correction of asymmetrical Spee and Wilson curves, are achievable with an accurate set-up planning. On the other hand, it underlines the necessity of mini-screws, auxiliaries and set-up overcorrections in order to obtain the best results.

Profile changes in extraction treatments of upper premolars: A case series.

This case series describes the soft tissue changes following extraction treatment in two patients with diverse lip thickness, but with similar baseline parameters including: labial competence, soft tissue profile, patient's age, extraction protocol, methods of anchorage, malocclusion, crowding, treatment appliance and mechanics. The same treatment plan involved upper first premolar extractions and lingual appliance combined with skeletal anchorage. The lip thickness played a crucial role in these cases, since a similar change of the incisor position leads to a different profile variation. This difference could be explained by the differing initial lip thicknesses as the patient with thin lips showed a more pronounced profilometric change. The choice of the ideal treatment plan must be tailored to the individual patient, taking into account not only initial skeletal and dental factors but also soft tissue factors, as well as the treatment goals.

Torque control with set-up and auxiliary spring in an adult severe class II case treated by lingual straight-wire appliance, premolar extractions and orthognathic surgery.

This case report describes a complex full-step class II high angle case in an adult patient treated with lingual straight-wire appliance, premolar extractions and orthognathic surgery. With the twofold aim of obtaining ideal occlusal relationship and aesthetic improvement, surgical treatment with appropriate biomechanical strategies, including extraction choice and torque control during space closure, are needed to achieve the planned results. This case report demonstrates the possibility of solving successfully severe sagittal, transverse and vertical discrepancies in an adult patient with surgical treatment by means of an invisible technique. This report also underlines the need for precise biomechanical control, including set-up overcorrections and an auxiliary spring to manage teeth inclination, in lingual orthodontics extraction cases.

Non-surgical occlusal plane cant resolution with lingual straight-wire appliance and miniscrews in a class II asymmetric adult patient.

This case report describes a complex class II case with important maxillo-mandibular asymmetry in an adult patient treated with lingual straight-wire appliance. With the twofold aim of obtaining dramatic aesthetic improvement, since the patient refused surgical option, and ideal occlusal relationship, accurate set-up planification and biomechanical strategies with TADS for occlusal plane cant correction are needed to achieve the planned results. This case report demonstrates the possibility of solving successfully class II malocclusion with significant asymmetry in adult patient without surgery by means of an aesthetic appliance; on the other hand, it underlines the necessity of miniscrews and auxiliaries in order to obtain the best results.

Invisible treatment of an asymmetric adult class II malocclusion related to unilateral upper lateral incisor agenesis with a straight wire lingual appliance, mini-screw and premolar extraction: A case report.

This case report describes a complex full-step class II malocclusion with unilateral upper lateral incisor agenesis in an adult patient treated with lingual straight-wire appliance and premolar extraction, with the two-fold aim of obtaining ideal occlusal relationship and smile aesthetic improvement. In view of this, it underlines how an appropriate treatment strategy, including extraction choice and anchorage control during space closure, is needed to achieve the planned results with a completely invisible lingual appliance combined with aesthetic veneers.

Accuracy of planned tooth movement with lingual straight wire technique.

OBJECTIVES: To analyze the accuracy of planned tooth movements of torque, tip, rotations, and transverse width values with lingual straight-wire technique. MATERIALS AND METHODS: 40 Caucasian subjects with mean age of 23.9 years, consecutively treated in private practice with a lingual straight-wire appliance (STb, Ormco, Glendora, Calif) were evaluated. Maxillary and mandibular dental casts were taken before treatment (T0), in the setup (T1), and at the end of treatment (T2) and scanned with an intraoral 3D scanner Carestream CS 3600 (Carestream Dental, Atlanta, GA). Virtual models at the three time points were superimposed on T1 using 3D software, and the coordinates were exported as a set of x, y, and z values. Angular and linear measurements were analyzed to measure torque, tip, rotation movements, and transverse intra-arch widths. Changes among the three time points were analyzed with Friedman's nonparametric test. RESULTS: A general increase in torque was recorded in the setup and in the final result, except for the maxillary molars. Torque, tip, and rotation movement mean accuracy was ≥84% for incisors, canines, and premolars. A general increase in transverse width was measured in the setup and in the final models, except for the upper second molars, which showed reduced transverse width during treatment. CONCLUSIONS: The movements planned in the setup to obtain the ideal torque, tip, and rotations actually occurred, except for second molars, which showed less accuracy. Planned expansion of the arches occurred only partially.

Stress Relaxation Properties of Five Orthodontic Aligner Materials: A 14-Day In-Vitro Study.

We aimed to investigate the stress relaxation properties of five different thermoplastic aligner materials subjected to 14 days of constant deflection. Five different thermoplastic aligner materials were selected, whose elastic properties varied: F22 Evoflex, F22 Aligner, Durasoft, Erkoloc-Pro and Duran. The static properties of these materials-in particular, stiffness, stress-strain curve and yield stress-were measured with a three-point bending test. For all the tests that were performed, a minimum of three samples per material were tested. The yield load, yield strength, deformation and particularly the stiffness of each material were found to be similar in the single-layer samples, while the double-layer samples showed far lower stiffness values and were similar one to another. F22 Evoflex and Erkoloc-Pro maintained the highest percentages of stress, 39.2% and 36.9%, respectively, during the 15-day period. Duran and Durasoft obtained the lowest final stress values, 0.5 MPa and 0.4 MPa, respectively, and the lowest percentage of normalized stress, 4.6% and 3.9%, respectively, during the 15-day period. All the materials that we tested showed a rapidity of stress decay during the first few hours of application, before reaching a plateau phase. The F22 Evoflex material showed the greatest level of final stress, with relatively constant stress release during the entire 15-day period. Further research after in vivo aging is necessary in order to study the real aligners' behavior during orthodontic treatment.

Comparative analysis of intraoral scanners accuracy using 3D software: an in vivo study.

BACKGROUND: The purpose of the present in vivo study was to compare the accuracy, in terms of trueness, between full-arch digital impressions of different intraoral scanning systems, using as a reference the ideality of the conventional impression technique. METHODS: Polyvinyl siloxane (PVS) two-step technique impressions of 27 subjects were taken, and the stone casts were scanned using desktop scanners R500 3Shape. For each arch, in vivo scans were taken with intraoral scanners Carestream CS3600, CEREC Omnicam and Trios 3Shape. All the files were compared, superimposing them on the reference model to calculate the total 3D and 2D deviations. The efficiency of the digital and conventional workflows was evaluated by measuring the work time in minutes. Statistical analyses were performed using R software (R Core Team 2020) with a p-value < 0.05. RESULTS: The three intraoral scanners differed from the PVS impression by differences of the order of 100-200 µm, and there was a trend of greater imprecision in the molar area in both dental arches. In comparison with PVS technique, CEREC tended to reduce the size of the impression, Trios presented the trend of greater precision, and Carestream showed minor differences the transversal distance. The areas of greatest discrepancy both in excess and in defect with respect to the PVS impression were the molar areas and incisal margins. Trios 3Shape recorded the shortest times and therefore with a more performing speed. CONCLUSION: The Trios 3Shape was found to be the most accurate single-tooth scanner, while the Carestream CS 3600 showed better inter-arch diameter performance compared to PVS impressions. The 3D and 2D analyses showed a trend of greater distortion of the impressions compared to the conventional one in the molar region.

Fluorescence-aided removal of orthodontic composites: an in vivo comparative study.

BACKGROUND: To compare the fluorescent properties of 6 different orthodontic adhesives and provide useful information for clinicians in the adhesion choice, in order to remove it easily at the end of orthodontic treatment by using the Fluorescence-aided Identification Technique (FIT). METHODS: Six orthodontic adhesives were included: Ortho Connect, Gradia LoFlo A3.5, Greengloo, Transbond XT, KommonBase Pink, and KommonBase Clear. The same thermoformed template with 1 mm shell thickness on the six anterior teeth was used for adhesive positioning; furthermore, an ultraviolet light-emitting diode flashlight was used for the FIT. The brightness of adhesive area and tooth area (L* color coordinate) were measured on the photographs by using the "color picker" tool of Photoshop software. RESULTS: GC Ortho Connect, Gradia Direct LoFlo and KommonBase Clear showed the highest differences of brightness (15.5, 16.3 and 13.5, respectively), while Greengloo, Transbond XT and KommonBase Pink registered similar values between resin area and tooth area with FIT (- 0.5, - 0.8 and - 1.0, respectively). The high viscosity adhesive resins, as Greengloo and Transbond XT, showed a similar performance in terms of fluorescence to the KommonBase Pink, the lowest viscous resin adhesive considered. CONCLUSIONS: The most used orthodontic adhesives showed different fluorescence properties. Some resins were brighter with the FIT, facilitating identification and subsequent removal. Other orthodontic adhesives presented no difference between adhesive and tooth. The viscosity of orthodontic adhesives did not influence the brightness emitted with FIT.

Non-surgical adult class II high-angle treatment with an invisible appliance: A case report.

This case report describes the complex situation of a young adult Class II hyperdivergent patient treated by premolar extraction with a straight wire lingual appliance. Despite the patient's refusal to undergo surgical treatment, the dual goals of ideal occlusal relationship and profile improvement were achieved through a well thought-out biomechanical strategy with appropriate extraction choice and anchorage control during space closure. This case report demonstrates the possibility of successfully resolving severe sagittal and vertical discrepancies in an adult patient without surgical treatment using a completely invisible technique. This report also highlights the need for careful planning during the diagnostic and treatment phases.

Comparative analysis of passive play and torque expression in self-ligating and traditional lingual brackets.

INTRODUCTION: The aim of this study was to determine and compare the play and torque expression of self-ligating and conventionally ligated lingual brackets, with square and rectangular slots, when engaged with archwires of different size, cross section and material. METHODS: Passive play and torque expression of 3 types of archwires and 5 types of brackets from four different manufacturers were measured and compared using a dynamometer. Each archwire was tested five times in each bracket; passive play was compared to ideal values, while torque expression was tested at 5, 10 and 20 Nmm as clinically efficacious values. RESULTS: Regarding full thickness stainless steel archwires, the lowest passive play was found in STb brackets (2.66 ± 0.89°, Ormco, Glendora, CA, USA), which was statistically significantly lower than for ALIAS brackets (4.44 ± 0.75°, Ormco), In-Ovation L brackets (6.14 ± 3.22°, Dentsply GAC, Bohemia, NY, USA), Harmony brackets (7.76 ± 2.94°, American Orthodontics, Sheboygan, WI, USA) and eBrace brackets (9.46 ± 3.94°, Riton Biomaterial, Guangzhou, China). Increasing the torsional load to the greatest torsional load clinically applicable, there were no statistically significant differences between STb, ALIAS, In-Ovation L and Harmony brackets. CONCLUSIONS: STb and ALIAS brackets generated the lowest passive play; STb and In-Ovation L brackets showed the lowest angle of play at the greatest torque expression. These measurements allow to understand the accuracy of lingual systems and at the same time the amount of overcorrections to be applied in the setup in order to obtain high quality orthodontic treatments.

Resolution of lower second molar impaction through miniscrew-supported biomechanics: A proposal for a simplified classification.

Two case reports are presented showing how the strategic use of skeletal anchorage via orthodontic miniscrews manages to solve the complex problems of orthodontic disimpaction of second mandibular molars with excellent anchorage control and reduction of the adverse effects common to the use of conventional methods. The temporary anchorage device (TAD)-mediated biomechanics used can be categorized as both "pulling from the distal side" and "pushing from the mesial side" techniques in which both direct and indirect anchorage mechanics were employed. Each of these mechanics has its advantages and disadvantages, which must be weighed and considered on a case-by-case basis. Based on the force application side and the type of anchorage, a simplified classification of TADs supported biomechanics for the recovery of fully or partially impacted second molars is proposed.

Fluorescence detected circular dichroism (FDCD) for supramolecular host-guest complexes.

Fluorescence-detected circular dichroism (FDCD) spectroscopy is applied for the first time to supramolecular host-guest and host-protein systems and compared to the more known electronic circular dichroism (ECD). We find that FDCD can be an excellent choice for common supramolecular applications, e.g. for the detection and chirality sensing of chiral organic analytes, as well as for reaction monitoring. Our comprehensive investigations demonstrate that FDCD can be conducted in favorable circumstances at much lower concentrations than ECD measurements, even in chromophoric and auto-emissive biofluids such as blood serum, overcoming the sensitivity limitation of absorbance-based chiroptical spectroscopy. Besides, the combined use of FDCD and ECD can provide additional valuable information about the system, e.g. the chemical identity of an analyte or hidden aggregation phenomena. We believe that simultaneous FDCD- and ECD-based chiroptical characterization of emissive supramolecular systems will be of general benefit for characterizing fluorescent, chiral supramolecular systems due to the higher information content obtained by their combined use.