Optimization of three-dimensional printing parameters for orthodontic applications.

OBJECTIVES: To determine the impact of build orientation, increased layer thickness, and dental crowding on the trueness of three-dimensional (3D)-printed models, and to evaluate how these parameters affect the fit of thermoformed appliances. MATERIALS AND METHODS: Ninety-six dental models were printed horizontally and vertically on the building platform using different 3D-printing technologies: (1) a stereolithography (SLA) printer with layer thicknesses of 160 µm and 300 µm and (2) a digital light processing (DLP) printer with layer thicknesses of 100 µm and 200 µm. Each printed model was digitalized and superimposed on the corresponding source file using 3D rendering software, and deviations were quantified by the root mean square values. Subsequently, a total of 32 thermoformed appliances were fabricated on top of the most accurate 3D-printed models, and their fit was evaluated by digital superimposition and inspection by three blinded orthodontists. Paired t-tests were used to analyze the data. RESULTS: Significant differences (P < .05) between printing technologies used were identified for models printed horizontally, with the SLA system achieving better trueness, especially in crowded dentitions. No significant differences between technology were found when models were printed vertically. The highest values of deviation were recorded in appliances fabricated on top of DLP-printed models. The results of the qualitative evaluation indicated that appliances fabricated on top of SLA models outperformed the DLP-modeled appliances. CONCLUSIONS: Three-dimensional printing with increased layer height seems to produce accurate working models for orthodontic applications.

Awareness of orthodontic patients towards smartphone orthodontic apps.

BACKGROUND: Mobile phone applications (apps) can potentially enhance patient care as they are easy to use and offer multifunctions. In 2019, 305 orthodontic apps were documented, many of which were patient-focused; however, there was little information on how popular these applications are with orthodontic patients. The main aim of this study was to evaluate how well patients were now aware of orthodontic applications. METHODS: A survey asking 700 orthodontic patients about their knowledge of, access to, and use of orthodontic apps to facilitate their treatment resulted in 615 responses. RESULTS: The results showed that a smartphone was owned by 96% of patients. Apple (Apple Inc., Cupertino, CA, USA) was the most used platform, followed by Android (Google LLC, Mountain View, CA, USA). Seventy-five percent of patients have previously used social media to research information, with YouTube (YouTube, San Mateo, CA, USA) being the most popular site. Only 3% of patients knew that applications were available to aid with orthodontic therapy and 12 patients had utilized an app linked to orthodontics. Nevertheless, 88% of patients said they would be open to using an app to supplement their treatment. CONCLUSIONS: Although 88% of patients said they would be prepared to use an app to help with orthodontic treatment, there is currently a low level of knowledge of the existence of apps. Given the availability of applications geared toward those patients, it is necessary to evaluate these apps' quality and, when critical, direct patients toward high-quality, efficient apps.

Nanotechnology in Orthodontics: Unveiling Pain Mechanisms, Innovations, and Future Prospects of Nanomaterials in Drug Delivery.

Orthodontic pain is characterized by sensations of tingling, tooth discomfort, and intolerance. According to the oral health report, over forty percent of children and adolescents have undergone orthodontic treatment. The efficacy of orthodontic treatment involving braces can be compromised by the diverse levels of discomfort and suffering experienced by patients, leading to suboptimal treatment outcomes and reduced patient adherence. Nanotechnology has entered all areas of science and technology. This review provides an overview of nanoscience, its application in orthodontics, the underlying processes of orthodontic pain, effective treatment options, and a summary of recent research in Nano-dentistry. The uses of this technology in healthcare span a wide range, including enhanced diagnostics, biosensors, and targeted drug delivery. The reason for this is that nanomaterials possess distinct qualities that depend on their size, which can greatly enhance human well-being and contribute to better health when effectively utilized. The field of dentistry has also experienced significant advancements, particularly in the past decade, especially in the utilization of nanomaterials and technology. Over time, there has been an increase in the availability of dental nanomaterials, and a diverse array of these materials have been extensively studied for both commercial and therapeutic purposes.

In Vitro Study of Tooth Surfaces After Interproximal Enamel Reduction: Extraoral Scanner and SEM Analysis

ABSTRACT Objective To perform a morphological evaluation concerning the extent of interproximal enamel reduction (IPR) with different manual instruments in different types of teeth and a qualitative analysis of enamel surface characteristics at the contact point before and after IPR. Material and Methods 40 freshly extracted, caries-free, and intact human teeth were used for the study (20 bicuspids and 20 incisors) and performed IPR just on the mesial surface. The morphological variation of contact point was evaluated by superimposed the stl file, obtained thanks to an extraoral scanner, at T0 and T1 for each tooth. Two types of strip were used, Intensiv Manual Ortho Strips Coarse/Medium and Steelcarbo Horico Strips. Teeth were then cut lengthwise, removed the most apical root portion and the mesial and distal halves were gilded and observed at different magnifications. Results The morphological variation following stripping mainly depends on the extent of the stripping, while the diameter, the type of strip and the shape of the tooth itself do not appear to be relevant. The 500X and 1500X magnifications allowed to appreciate better the characteristics of the surface of the stripped enamel and the differences with the intact enamel. All teeth treated, independently from the kind of strip used, shows deep marks and grooves in the direction of stripping. In both cases, the enamel appears significantly damaged at great magnifications. Conclusion Stripping always and inevitably leads to a change in the shape of the contact point and is directly correlated to the amount of stripping performed. The use of polishing after the removal of enamel interproximal is necessary in all cases.

Impact of Early Loss of Lower First Permanent Molars on Third Molar Development and Position

ABSTRACT Objective: To evaluate the effects of unilateral loss of the lower first permanent molar (L6) on the position and development of the lower third molar (L8). Material and Methods: Fifty-four panoramic radiographs of subjects with unilateral loss of L6 were examined. The L8 on the side of the L6 loss was compared with the L8 in the hemiarch without L6 loss (contralateral). The effect of L6 loss on the positioning of L8 was examined in all the samples (n=54), whereas the effect on the development of the third molar was examined in 38 patients with L8 with incomplete root formation. The Signs statistical test was used to evaluate the comparison between loss and contralateral hemiarches. Results: In 20 (37%) of 54 subjects, the L8 was better positioned in the hemiarch with loss of the lower first molar (p<0.001) compared with the control side. In the remaining 34 subjects, no difference was found. When only the L8 considered as impacted on the control side was examined (n=30), the cases with better positioning on the side with L6 loss increased to 66.6% (p<0.001). Conclusion: The loss of lower first molars improves the position of the lower third molar during its active eruption, mainly when the lower third molar is impacted. However, L6 loss does not affect the root development of lower third molars.

The Herbst appliance combined with a completely customized lingual appliance: A retrospective cohort study of clinical outcomes using the American Board of Orthodontics Objective Grading System.

OBJECTIVES: In this retrospective study we aimed to evaluate the quality of treatment outcomes using the American Board of Orthodontics (ABO) scoring system with a completely customized lingual appliance used in combination with a Herbst appliance for Class II correction. MATERIALS AND METHODS: Patient selection criteria for this study were Class II division 1, II/2 or subdivision treated with a WIN® lingual appliance combined with an L-pin Herbst device. Thirty-two consecutively debonded cases were included in this retrospective case series. Pre- and post- treatment dental casts, dental set-ups, panoramic X-rays, cephalometric analysis, photographs and clinical files were available for data collection. The primary outcome was the ABO score based on the Discrepancy Index (ABO DI) including: overjet, overbite, anterior open bite, lateral open bite, crowding, occlusion (Angle class), lingual posterior crossbite, buccal posterior crossbite, ANB, IMPA and SN-GoGN angles and the Cast-Radiograph Evaluation (ABO CR-Eval) comprising of alignment/rotations, marginal ridges, buccolingual inclination, overjet, occlusal contacts, occlusal relationship (Angle class), interproximal contacts and root angulation. In addition, overjet, overbite and Class II correction were also evaluated on pre- and post-treatment models. The secondary outcome was bracket failure and complications related to the Herbst device. RESULTS: The study cohort included 18 female and 12 male patients with a mean age of 15.8 (range 12, 6- 18, 5). Twenty patients were Class II division 1 and ten were Class II division 2. The mean pre-treatment value of ABO DI was 20.8 (range 10-39); more than two-thirds of the sample were rated as being either of moderate difficulty (ABO DI: 16-24) or severe (ABO DI: over 25). The average post-treatment ABO Cast-Radiograph Evaluation score was 15.0 (SD=4.4), which is considered a passing score. Twenty-six patients had a score equal or lower than 20 (undisputed passing score). The Class II discrepancy was effectively corrected from a score of 16.83 penalty points (SD: 3.65) pre-treatment to a score of 1.57 (SD: 1.70) post-treatment. No association was found between initial and final Class II occlusal relationships (P=0.42), indicating that regardless of the initial discrepancy, no difference in the success of Class II correction was observed. The mean bracket failure rate was 3.8 per patient. Herbst related complications were few: 1.6 per patient, with the majority of complications being of little consequence and with 43% of the patients having no breakages. CONCLUSION: The completely customized lingual appliance assessed in this study combined with an L-pin Herbst led to effective Class II correction regardless of the initial severity of the sagittal discrepancy. The average ABO CR-Eval score for this sample was well below the undisputed passing score indicating a high quality of treatment outcomes.

Pairing orthodontic adhesive resins and light-curing units for optimal degree of conversion.

OBJECTIVES: The purpose of this study was to identify the combination of orthodontic adhesive resins and light-emitting diode (LED) light-curing units (LCUs) that result in the highest degree of resin conversion (DC). The hypothesis tested was that pairing orthodontic resins with LCUs from the same manufacturer produces higher DC versus unpaired resins and LCUs. METHODS: Pre-polymerization spectra of adhesive resins (Transbond XT [3M Unitek], BracePaste [American Orthodontics] or Opal Bond MV [Opal by Ultradent]) were obtained at oral temperature (37°C) using an attenuated total reflectance (ATR) diamond crystal (Golden Gate, Specac) in a Fourier-transform infrared (FTIR) spectrometer (Nicolet IS50). Resin specimens were polymerized using various LCUs (Ortholux Luminous [3M Unitek], Blue Ray 3 [American Orthodontics], or VALO Ortho Cordless [Ultradent Products, Inc.]) before obtaining post-polymerization infrared (IR); spectra. Twelve LCU-resin combinations were tested (n = 20/combination), half with a bracket present (Mini Diamond Twin, Ormco) and half without. DC values (%) were calculated using the two-frequency method and tangent-baseline technique. Data for each resin were statistically analyzed using General Linear Models and Student-Newman-Keuls post hoc tests (α = 0.05). RESULTS: Statistically significant differences were found within each resin for the groups without brackets present (P < 0.0001), the groups with brackets present (P < 0.0001), and the groups with brackets when compared with the manufacturer-paired group without a bracket (P < 0.0001). CONCLUSIONS: Adhesive resins and LCUs from the same manufacturer did not consistently result in statistically higher mean DC values than unpaired combinations. Metal brackets do not uniformly reduce the degree of conversion of adhesive resins when assessed using IR spectrometry.

Treatment outcome of oral appliance in patients with REM-related obstructive sleep apnea.

PURPOSE: Oral appliances (OA) are used to treat patients with obstructive sleep apnea (OSA). The purpose of this study is to evaluate the efficacy of OA treatment in patients with rapid eye movement (REM)-related OSA. METHODS: Forty-six patients with REM-related OSA and 107 with non-stage-specific OSA were prescribed OA treatment after diagnosis by polysomnography (PSG) and a follow-up sleep test by PSG was conducted. Efficacy and treatment outcome predictors were evaluated according to the following criteria for treatment success: #1, reduction of the apnea-hypopnea index (AHI) to less than 5 and > 50% compared with baseline; #2, AHI reduction to less than 10 and > 50% compared with baseline; and #3, > 50% AHI reduction compared with baseline. RESULTS: Success rates according to criteria #1, #2, and #3 were 45.7%, 50.0%, and 50.0% in REM-related OSA and 36.4%, 52.3%, and 63.6% in non-stage-specific OSA, respectively. No significant differences in success rate were found between the two groups. In multivariate logistic regression analysis with each criterion as the response variable, only BMI was extracted as a significant predictor. The BMI cutoff values defined based on the maximum Youden index according to the three criteria were 26.2 kg/m2, 25.6 kg/m2, and 26.2 kg/m2, respectively. CONCLUSIONS: No significant differences in success rate of OA treatment were found between REM-related OSA and non-stage-specific OSA. BMI has greater impact on treatment outcome of OA in patients with REM-related OSA.

Distortion and magnification of four digital cephalometric units.

OBJECTIVES: To assess the validity of using the calibration ruler for correcting magnification of linear measurements and to explore and compare the vertical and horizontal magnification of four digital cephalometric units. METHODS: An acrylic box was imaged at seven sagittal positions using four digital cephalometric units: Orthopantomograph OC100, Orthopantomograph OC200, Sirona Orthophos CD, and Sirona Orthophos DS. The true linear lengths of the phantom, corrected, and uncorrected linear lengths on the images were measured and compared. The validity of measurements using the calibration ruler was assessed. The magnification values and distortion indices were calculated and compared among the four cephalometric units. RESULTS: For linear measurements on the mid-sagittal plane and averaged linear measurements on bilateral symmetric sagittal planes, the bias 1.96 STD of the calibration ruler ranged from 1% to 2% for the four cephalometric testing units. For linear measurements on the single lateral sagittal plane, the bias 1.96 STD ranged from 3% to 6%. The vertical scanning charge-coupled device cephalometric unit produced the greatest distortion, ranging from 1.029 to 0.964. CONCLUSION: The metal millimeter calibration ruler is an accurate reference for linear measurement magnification correction. Because of unpredictability and machine specificity, the magnification and distortion of a cephalometric unit should be calibrated for the estimation of cephalometric measurement error.

Long-term effects of functional appliances in treated versus untreated patients with Class II malocclusion: A systematic review and meta-analysis.

OBJECTIVE: To assess the cephalometric skeletal and soft-tissue of functional appliances in treated versus untreated Class II subjects in the long-term (primarily at the end of growth, secondarily at least 3 years after retention). SEARCH METHODS: Unrestricted electronic search of 24 databases and additional manual searches up to March 2018. SELECTION CRITERIA: Randomised and non-randomised controlled trials reporting on cephalometric skeletal and soft-tissue measurements of Class II patients (aged 16 years or under) treated with functional appliances, worn alone or in combination with multi-bracket therapy, compared to untreated Class II subjects. DATA COLLECTION AND ANALYSIS: Mean differences (MDs) and 95% confidence intervals (95% CIs) were calculated with the random-effects model. Data were analysed at 2 primary time points (above 18 years of age, at the end of growth according to the Cervical Vertebral Maturation method) and a secondary time point (at least 3 years after retention). The risk of bias and quality of evidence were assessed according to the ROBINS tool and GRADE system, respectively. RESULTS: Eight non-randomised studies published in 12 papers were included. Functional appliances produced a significant improvement of the maxillo-mandibular relationship, at almost all time points (Wits appraisal at the end of growth, MD -3.52 mm, 95% CI -5.11 to -1.93, P < 0.0001). The greatest increase in mandibular length was recorded in patients aged 18 years and above (Co-Gn, MD 3.20 mm, 95% CI 1.32 to 5.08, P = 0.0009), although the improvement of the mandibular projection was negligible or not significant. The quality of evidence was 'very low' for most of the outcomes at both primary time points. CONCLUSIONS: Functional appliances may be effective in correcting skeletal Class II malocclusion in the long-term, however the quality of the evidence was very low and the clinical significance was limited. SYSTEMATIC REVIEW REGISTRATION: CRD42018092139.

[Evaluation of dental medical devices: Focus on the definition of needs]. / Évaluation des dispositifs médicaux dentaires pour un appel d'offres : privilégier la haute définition des besoins.

OBJECTIVES: As a university teaching hospital, the call for tender for dental medical devices (dental implants and consumables) is done with the help of a team of hospital pharmacists and users. In order to optimize the definition of needs and evaluation criteria, an exhaustive review of the products was carried out. METHODS: Dental medical devices suppliers were consulted in 2017 for reviewing their products. Their technical, clinical and economic data were compared. The products have been gathered into categories and its results had been submitted to a commission of dental experts of our university hospital for clinical opinion. RESULTS: More than 30,000 references from 30 different suppliers were analyzed (orthodontics, dental implants, membranes and bone substitutes, various dental consumables). Relating to oral implantology, the opinions converged on clinical studies. On the contrary, diverging opinions have been proffered on the systematic use of single-use drills and customized guides for surgery and on the implant's choice. The definition of needs has been specified for orthodontics and consumables. Other criteria played a great role: single packaging (unit doses), product's sterility, paediatric needs, presence of allergens, traceability of devices and supplier diversity. CONCLUSIONS: This review led to the identification of new needs in more precise terms. The complexity and diversity of dental products and techniques requires this careful review and a better collaboration with practitioners.

Dentoskeletal and soft tissue changes associated with miniscrew anchorage in customized lingual orthodontics.

OBJECTIVES: The goal of this study was to analyze skeletal, dental, and soft tissue changes of patients treated with customized lingual systems and to evaluate the clinical effectiveness of miniscrew anchorage. METHODS: Nine upper first premolar extraction patients who were treated with customized lingual appliances were included in this study. Miniscrews were used for reinforcement of molar anchorage. Cephalometric films and study models were obtained before treatment (T1), after alignment (T2), and after treatment (T3). Treatment effects were analyzed by cephalometric radiographs and study models. RESULTS: The upper anterior teeth were retracted significantly at T2 and T3 (4.41 ± 4.14 mm and 5.51 ± 2.48 mm, respectively). During space closure, the upper first molars showed slight mesial movement (1.50 ± 1.97 mm). The intercanine width of the upper arch increased at T2 (1.59 ± 1.81 mm), but decreased at T3 (0.11 ± 1.00 mm). The sella-nasion-A, A-nasion-B, and mandibular plane angles were not significantly changed at T3. The upper lip showed continuous retraction at both T2 and T3 (1.40 ± 1.46 mm and 2.32 ± 2.48 mm, respectively). CONCLUSIONS: By using miniscrew anchorage for lingual orthodontics, patients' dental and soft tissue changes considerably improved and molar anchorage was reinforced.

Effect of photodynamic therapy on surface decontamination in clinical orthodontic instruments.

The objective was to develop, characterize and test a box containing light emission diode (LED), Patent Deposit MU-BR20.2017.002297-3, which was named "Photodynamic Inactivation Device" (PID) and verify if it's suitable in microbial reduction or disinfection action of solid surfaces using PID. The equipment was made in a container of polypropylene with a lid of the same material and, for a better use of irradiation the internal part was covered with a layer of reflective aluminum. In addition, sixty boards of red LED 660 nm wavelength, containing three radiators each, for which the distribution of irradiation and spectral irradiance in all of the six internal faces were calculated in this device. That way, a low cost alternative was tested over three types of microorganisms present on the human microbiota: two strains Gram-positive (Gram +), Staphylococcus aureus and Streptococcus mutans and one strain Gram-negative (Gram -), Escherichia coli, inoculated in orthodontic instruments previously autoclaved. To assess the Photodynamic Inactivation (PDI) over these bacteria, instruments were contaminated by bacterial suspensions (3 × 108 CFU/mL) and ulterior treatment with a solution of 100 µmol/L of MB for 20 min, and irradiated for another 20 min (energy density of 026 J/cm²). Microbial reduction was assessed by number counting of Colony Forming Units (CFU). At the end, microbial reduction of the surface of orthodontic metal instruments was compared with the positive group of each group. Results showed that PID caused a significant reduction (p < 0.05) of the microbial charge stuck in the orthodontic instruments. Thus, the photo prototype of the drawing is appropriate for phototherapy studies, granting it´s advantageous to the low level light therapy as well as for the antimicrobial photodynamic therapy. The perspective is that PID may potentialize the dissemination of phototherapy studies for determining its proper use in health science. And, thus, propose a low cost and atoxic alternative for disinfection of biomedical appliances as non-critical instruments, allowing also for use in the food industry.

[Adult orthodontics for a better prosthesis]. / L'orthodontie adulte pour une meilleure prothèse.

INTRODUCTION: Adult patients are seen more frequently in our orthodontic offices. Unlike the adolescent, the adult patient will often need a multidisciplinary approach due to tooth migrations secondary to extractions or periodontal disease. MATERIALS AND METHODS: This article will address the indications and orthodontic solutions to various restorative problems relative to the adult patient. Specific orthodontic mechanics aimed at facilitating and improving the prosthetic outcomes will be described and illustrated with clinical cases.

European College of Orthodontics: Commission of Affiliation and Titularisation.

DATE OF BIRTH: 14/04/2000; sex: female. A. PRETREATMENT RECORDS: 12 y and 2m; 7/6/2012. DIAGNOSIS: The patient presents a left subdivision Angle's class II malocclusion associated with an incisor deep bite of 5mm and a deviation of the mandibular incisor midline to the left (of the patient). On a frontal view, we also note a slight asymmetry of the lower part of the face, the tip of the chin is slightly deviated to the left (of the patient). However, the patient presents a good labial occlusion at rest, a normal divergence and a harmonious face. TREATMENT PLAN: Bimaxillary multibracket appliance using Roth technique .022×.028'' with placement of the appliance in the maxillary before the mandible to allow the unlocking of the mandibular occlusion, then implementation of a class II appliance with intermaxillary traction elastics. B. POSTTREATMENT RECORDS: 13 y and 8m; 10/12/2013. DURATION OF ACTIVE TREATMENT: 18 months, good stability of the occlusion, preservation of the incisor midlines and of the deep bite. RETENTION: Maxillary: palatal wire bonded from teeth 12 to 22 and thermoformed splint; mandibular: lingual wire bonded from teeth 33 to 43 and thermoformed splint. C. POSTRETENTION RECORDS: (Minimum of 1 year): 15 years old; 3/4/2015.