Three-dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni-ti leaf springs expander and rapid maxillary expander: A two-centre randomized controlled trial.

OBJECTIVE: The aim of this randomized controlled trial (RCT) was to evaluate the spontaneous distorotation of upper first permanent molars and the transverse dentoalveolar changes on digital casts in growing patients following maxillary expansion treatment using either the Leaf Expander® or the rapid maxillary expander (RME), both anchored to the deciduous second molar. TRIAL DESIGN AND SETTING: This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy. PARTICIPANTS: Inclusion criteria included maxillary transverse deficiency, prepubertal development stage (cervical vertebra maturation stage [CVMS] 1-2) and early mixed dentition with fully erupted upper first permanent molars. Exclusion criteria were systemic diseases or syndromes, CVMS 3-6, agenesis of upper second premolars, unavailability of the second deciduous molar for anchorage and Class III malocclusion. RANDOMIZATION: Patients were randomly assigned to the Leaf Expander® or RME group using a computer-generated randomization list created by a central randomization centre. Randomization was conducted immediately before the start of treatment. INTERVENTION: The intervention involved treatment with either the Leaf Expander® or the RME. Both devices were anchored to the second deciduous molars. Following randomization, patients were further categorized based on the presence of no crossbite, unilateral crossbite or bilateral crossbite. MAIN OUTCOME MEASURE: The primary outcome measure was the distorotation of the upper first molar (U6). Secondary outcomes included measurements of interdental linear dimensions, specifically upper inter-canine width (53-63), upper inter-molar width (MV16-MV26) and upper inter-deciduous second molar width (55-65). BLINDING: The examiner analysing the digital casts was blinded to the treatment groups to prevent detection bias and ensure objective assessment. However, due to the nature of the intervention, blinding was not feasible for the patients and clinicians involved in administering the treatment. RESULTS: A total of 150 patients were enrolled and randomly assigned to two groups: 75 to the Leaf Expander® group and 75 to the RME group. Recruitment started in November 2021 and was completed in November 2022. At the time of analysis, the trial was complete with no ongoing follow-ups. ANOVA tests revealed no significant differences between the three subgroups (no-cross, unilateral-cross and bilateral-cross) within both the Leaf Expander® and RME groups at T0. The Leaf Expander® demonstrated significantly greater distorotation in the unilateral crossbite subgroup compared to the RME (p = .014). In terms of total molar distorotation, the Leaf Expander® appliance showed a significantly greater effect (12.66°) compared with conventional RME (7.83°). Linear regression analysis demonstrated a significant correlation between the extent of expansion and the degree of molar rotation. CONCLUSIONS: Maxillary expansion resulted in significant spontaneous molar distorotation when the appliance was bonded to the second deciduous molars. The Leaf Expander® exhibited significantly greater molar distorotation compared with conventional RME. The degree of molar distorotation was correlated with the extent of expansion obtained on the second deciduous molar. TRIAL REGISTRATION: The trial was registered at ClinicalTrials.gov (ID: NCT05135962).

Skeletal and dental effects of serial extractions performed with or without maxillary expansion-A retrospective controlled study.

OBJECTIVES: The study aimed to compare severe crowding treatment's skeletal and dental effects by serial extractions or maxillary expansion and serial extractions in the mixed dentition phase. SETTING AND SAMPLE POPULATION: The retrospective controlled study included lateral cephalograms of 78 subjects aged 8.5 ± 1.4 years, 52 consecutively treated because of severe crowding, and 26 untreated controls matched for baseline age and observational period. METHODS: Subjects were clustered according to the treatment modality, either serial extraction (EX) or expansion and extraction (EXP-EX) group. Sagittal and vertical skeletal as well as dental cephalometric parameters were assessed at baseline and after the eruption of all permanent posterior teeth, and group comparisons were performed. RESULTS: Both treatment modalities significantly affected the vertical skeletal parameters in terms of decreasing the mandibular and occlusal plane inclination and increasing the facial height index. A distinct treatment effect on the gonial angle was observed, with a significant decrease in its superior part observed in both extraction groups. The annualized changes in the superior part of the gonial angle significantly differ (P = .036) between the Control (-0.04 ± 0.6), EX (-0.44 ± 0.6) and EXP-EX (-0.34 ± 0.5) groups. Upper and lower incisor inclination did not change significantly in any of the groups; however, the interincisal angle at follow-up was significantly smaller in the Control compared with both treated groups. CONCLUSIONS: Serial extractions and a combination of maxillary expansion and serial extractions have similar significant skeletal effects, mainly affecting vertical cephalometric parameters if performed during the pre-pubertal growth phase.

Tooth automatic segmentation from CBCT images: a systematic review.

OBJECTIVES: To describe the current state of the art regarding technological advances in full-automatic tooth segmentation approaches from 3D cone-beam computed tomography (CBCT) images. MATERIALS AND METHODS: In March 2023, a search strategy without a timeline setting was carried out through a combination of MeSH terms and free text words pooled through Boolean operators ('AND', 'OR') on the following databases: PubMed, Scopus, Web of Science and IEEE Explore. Randomized and non-randomized controlled trials, cohort, case-control, cross-sectional and retrospective studies in the English language only were included. RESULTS: The search strategy identified 541 articles, of which 23 have been selected. The most employed segmentation methods were based on deep learning approaches. One article exposed an automatic approach for tooth segmentation based on a watershed algorithm and another article used an improved level set method. Four studies presented classical machine learning and thresholding approaches. The most employed metric for evaluating segmentation performance was the Dice similarity index which ranged from 90 ± 3% to 97.9 ± 1.5%. CONCLUSIONS: Thresholding appeared not reliable for tooth segmentation from CBCT images, whereas convolutional neural networks (CNNs) have been demonstrated as the most promising approach. CNNs could help overcome tooth segmentation's main limitations from CBCT images related to root anatomy, heavy scattering, immature teeth, metal artifacts and time consumption. New studies with uniform protocols and evaluation metrics with random sampling and blinding for data analysis are encouraged to objectively compare the different deep learning architectures' reliability. CLINICAL RELEVANCE: Automatic tooth segmentation's best performance has been obtained through CNNs for the different ambits of digital dentistry.

Evaluation of the effects on SpO2 of N95 mask (FFP2) on dental health care providers: a cross-sectional observational study.

OBJECTIVE: The purpose of this cross-sectional observational study was to evaluate the effects of SpO2 in a sample of dental health care providers who wear a N95 mask or Filtering Face Piece (FFP2) for four consecutive hours, measured by a pulse oximeter before donning the mask and again after four hours of work and to offer some strategies to minimize discomfort and improve communication with their patients while wearing the mask. MATERIALS AND METHODS: A 17-item questionnaire was sent via Google Drive to various practitioners in Italy and the USA. A sample of 162 questionnaires were returned from dentists, orthodontists, dental hygienists and dental assistants who committed to wearing a FFP2 for 4 consecutive hours during a work day and then measuring the oxygen saturation by way of a pulse oximeter before and after the 4 working hours. The final analysis was performer on 147 viable questionnaires returned. The sample was composed of 62 males and 85 females with an average age of 42.9 ± 12.0 years. RESULTS: For the entire sample population, the baseline saturation was 98.6 ± 1.2 and, after four hours of mask wearing, there was a significant decrease in oxygen saturation to 97.0 ± 2.9 (p < 0.01). No statistical differences in SpO2 were found across specialties or across types of procedures performed during the 4 h. Heart rates were not significantly different before and after the 4 h in all categories. The 3 most frequent reported complaints were: fatigue (64%), headache (36%) and external ear pain (31%). The most common additional personal protective equipment (PPE) was a mask shield (78%) and those who wore the mask continuously reported more communication difficulty with patients, compared with those who took the mask off more often, in fact, 64% of the subjects reported that using the mask influenced their communication with their patients. Based on the results of the questionnaire, a list of breathing and vocal folds health strategies was devised and proposed, along with strategies to augment communication with patients. CONCLUSIONS: This study highlights a significant decrease in oxygen saturation after only 4 h of work (except for smokers) while wearing a FFP2, and confirms the widespread symptoms of fatigue, headache and pain behind the ears that dental professionals experience. But it also highlighted how mask wearing impaired communication with patients and wearing additional masks and a facial shield may add to those communications difficulties. This aspect and the need for better communication can lead the operators to remove the mask to improve breathing and communication, thus putting themselves at a risk of infection. Of all the aspects explored in this study, the most interesting was indeed the impact on fatigue and communication and the strategies proposed in this article can easily be implemented to reduce headache and fatigue by improving breathing efficiency and by aiding communication while donning a mask by improving voice quality and by using augmentative communication tools.

Diagnostic ability of the primary second molar crown-to-root length ratio and the corresponding underlying premolar position in estimating future expander anchoring teeth exfoliation.

OBJECTIVES: The aim was to assess the diagnostic ability of the crown-to-root length ratio of the primary second molar and the position of the corresponding underlying premolar in estimating future anchoring teeth exfoliation during maxillary expansion. SETTING AND SAMPLE POPULATION: Fifty-four subjects (30 females, 24 males; 108 teeth) aged 8.2 ± 1.0 years that underwent palatal expansion. METHODS: The upper second premolar position of the corresponding expander anchoring primary molar was determined in relation to the ipsilateral first permanent molar half-pulp chamber (HPC) line on panoramic radiographs. Subjective and objective (based on measurements) assessments of the crown-to-root length ratio of anchoring primary molars were performed. Exfoliation after the expansion was recorded over a retention period of 12 months. All the assessments were performed individually by three examiners at two 3-week-apart sessions, trained and calibrated before enrolment. The intra-/inter-examiner agreements were evaluated, and the diagnostic accuracy of the methods was calculated. RESULTS: All methods exhibited almost perfect intra- and at least substantial inter-examiner agreement (Kappa >0.8 and ≥0.63, respectively). Good diagnostic accuracy was seen for the premolar position to the HPC line (0.7-0.8), while the crown-to-root length ratio methods exhibited hardly sufficient accuracy. The diagnostic agreement of the methods was fair. CONCLUSIONS: When primary molars are considered as anchoring teeth for maxillary expansion, the premolar position in relation to the HPC line appears to be the most valid and reliable method for predicting their stability. Despite high repeatability values, the crown-to-root length ratio needs a cut-off point re-definition to increase its predicting ability.

Factors related to maxillary expander loss due to anchoring deciduous molars exfoliation during treatment in the mixed dentition phase.

OBJECTIVES: The aim was to identify factors associated with maxillary expander loss due to anchoring deciduous molars exfoliation and assess the diagnostic accuracy of the upper second premolar cusp position as a prognostic factor for the exfoliation of its corresponding deciduous molar. MATERIALS/METHODS: Ninety-two subjects aged 8.4 ± 1.1 years, treated with a Haas or hyrax expander, and using the same expansion protocol and deciduous teeth as anchorage were included. The position of the upper second premolar cusp, according to the half pulp chamber (HPC) line of the ipsilateral upper first permanent molar, was assessed on pre-treatment panoramic radiographs. RESULTS: A significant association between anchoring deciduous molar exfoliation and the position of the upper second premolar cusp according to the HPC line (P = 0.002; odds ratio = 5.7) was seen, while there was no association with gender, age, treatment duration, and type of expander. The median survival time for an anchoring deciduous molar, when the underlying premolar cusp was touching/crossing the HPC line, was 13.0 (11.7; 14.2) months. The upper second premolar cusp position to the HPC line showed high accuracy (at least 76.11 per cent) and substantial repeatability (at least 0.7) as a prognostic factor for the corresponding second deciduous molar exfoliation. LIMITATIONS: Applicability in the mixed dentition phase with fully erupted upper first permanent molars. CONCLUSIONS: The probability of a second deciduous molar to be successfully used as maxillary expander anchorage for at least 16 months is above 94 per cent; when at baseline, the corresponding premolar cusp is apical to the HPC line.

Platelet-Rich Fibrin in Single and Multiple Coronally Advanced Flap for Type 1 Recession: An Updated Systematic Review and Meta-Analysis.

Background and Objectives: The aim of the present systematic review and meta-analysis was to investigate the efficacy of leukocyte-platelet-rich fibrin (L-PRF) in addition to coronally advanced flap (CAF) for the treatment of both single and multiple gingival recessions (GRs) compared to the CAF alone and to the adjunct of connective tissue graft (CTG). Root coverage outcomes using platelet concentrates have gained increased interest. In particular, it has been suggested that adding L-PRF to CAF may provide further benefits in the treatment of GRs. Materials and Methods: An electronic and manual literature search was conducted to identify randomized controlled trials (RTCs) investigating root coverage outcomes with CAF + L-PRF. The outcomes of interest included mean root coverage (mRC), recession reduction, keratinized tissue width (KTW) gain, gingival thickness (GT) gain, and patient-reported outcome measures (PROms) such as pain perception and discomfort. Results: A total of 275 patients and 611 surgical sites were analyzed. L-PRF in adjunct to single CAF seems to show statistically significant results regarding clinical attachment level (CAL) with a weighted means (WM) 0.43 95% CI (-0.04,0.91), p < 0.0001, GT (WM 0.17 95% CI (-0.02,0.36), p < 0.0001, and mRC (WM 13.95 95% CI (-1.99,29.88) p < 0.0001, compared to single CAF alone. Interesting results were obtained from the adjunct of PRF to multiple CAF with respect to multiple CAF alone with an increase in the mRC WM 0.07 95% CI (-30.22,30.35), p = 0.0001, and PPD change WM 0.26 95% CI (-0.06,0.58), p < 00001. On the other hand, no statistically significant data were obtained when L-PRF was added to single or multiple CAF combined with CTG according to the included outcomes such as mRC (p = 0.03 overall). Conclusions: L-PRF is a valid alternative to CAF alone. L-PRF compared to CTG in single and multiple CAF showed statistically significant results regarding pain perception and discomfort PROms (p < 0.0001). However, CTG remains the gold standard for treating gingival recession.

The Implications of Artificial Intelligence in Pedodontics: A Scoping Review of Evidence-Based Literature.

BACKGROUND: Artificial intelligence (AI) has emerged as a revolutionary technology with several applications across different dental fields, including pedodontics. This systematic review has the objective to catalog and explore the various uses of artificial intelligence in pediatric dentistry. METHODS: A thorough exploration of scientific databases was carried out to identify studies addressing the usage of AI in pediatric dentistry until December 2023 in the Embase, Scopus, PubMed, and Web of Science databases by two researchers, S.L.R. and A.L.G. RESULTS: From a pool of 1301 articles, only 64 met the predefined criteria and were considered for inclusion in this review. From the data retrieved, it was possible to provide a narrative discussion of the potential implications of AI in the specialized area of pediatric dentistry. The use of AI algorithms and machine learning techniques has shown promising results in several applications of daily dental pediatric practice, including the following: (1) assisting the diagnostic and recognizing processes of early signs of dental pathologies, (2) enhancing orthodontic diagnosis by automating cephalometric tracing and estimating growth and development, (3) assisting and educating children to develop appropriate behavior for dental hygiene. CONCLUSION: AI holds significant potential in transforming clinical practice, improving patient outcomes, and elevating the standards of care in pediatric patients. Future directions may involve developing cloud-based platforms for data integration and sharing, leveraging large datasets for improved predictive results, and expanding AI applications for the pediatric population.

What is the impact of patient attributes, implant characteristics, surgical techniques, and placement location on the success of orthodontic mini-implants in young adults? A Systematic Review and Meta-Analysis.

Background: Temporary anchorage devices (TADs) address challenges in traditional orthodontic anchorage like patient compliance and precision, showing significantly improved clinical outcomes, particularly for cases requiring maximum anchorage. Materials and Methods: A systematic electronic search was performed in five research databases, focusing on studies published between 2015 and 2023. The ROBINS-I tool from the Cochrane Bias Methods Group assessed the risk of bias. Data analysis included categorical and numerical variables, with categorical variables analyzed using Cohen's method in a random effects model to account for variability. Sensitivity and heterogeneity were evaluated using a 'leave-one-out' approach and the I 2 statistic, respectively. At the same time, publication bias was checked using Egger's test, with findings presented through Forest and Funnel plots. Numerical variables were subjected to weighted regression analysis. Results: Examination of 15 studies involving 1981 patients and 3272 orthodontic mini-implants identified key factors affecting implant stability. Failure rates varied significantly, influenced by factors such as the characteristics and insertion site of the orthodontic mini-implants (OMIs), patient-specific variables, and operator experience. Notably, the insertion site and implant characteristics like size did not significantly affect failure rates, but there was a negative correlation between the magnitude of force applied and failure rates. Conclusion: The success of orthodontic mini-implants is broadly consistent across patient demographics and is not significantly impacted by gender or age, though failure rates were higher in males and when implants were placed in the maxilla. These findings suggest that higher applied forces might reduce failure rates. Clinical Significance: This review underlines mini-implant efficacy across varied patient demographics, emphasizing the importance of site selection, jaw location, and force application in enhancing success rates and guiding tailored treatment strategies.PROSPERO ID CRD42023411955.

Use of Edibles as Effective Tools in Myofunctional Therapy: A Pilot Study.

AIM: The aim of this retrospective study is to explore the introduction of edible spread cream and small candies as tools to improve motivation and compliance in young children undergoing myofunctional therapy, with the purpose of optimizing oral functions, including swallowing. METHODS: Six patients, one female and five males, between the ages of 7 and 14 years, presenting with atypical swallowing, were evaluated and treated at the clinic of the University of L'Aquila. The patients included in the study were randomly divided into two groups and were treated with two different treatment protocols: Group A: traditional myofunctional therapy and traditional tools; Group B: same exercises as group A, but with edible tools (spreadable cream and small candies). RESULTS: As expected, the two patients who used edible tools demonstrated increased motivation and collaboration during myofunctional therapy. CONCLUSIONS: Patient compliance, especially in very young patients, limits the effectiveness of myofunctional therapy; therefore, creative solutions are needed to achieve greater cooperation, and edible tools can play a significant part in retraining correct swallowing. Although the sample of this pilot study is small, the results suggest that using actual edible tools in myofunctional therapy could increase compliance and provide better results in myofunctional therapy.

A spectroscopic study on orthodontic aligners: First evidence of secondary microplastic detachment after seven days of artificial saliva exposure.

Clear orthodontic aligners have recently seen increasing popularity. The thermoplastic materials present several advantages, even if it is known that all plastic products can be subjected to environmental and mechanical degradation, leading to the release of microplastics (MPs). Their ingestion could cause oxidative stress and inflammatory lesions. This study aims to evaluate the potential detachment of MPs by clear aligners due to mechanical friction simulated with a 7-day protocol in artificial saliva. The study was performed on orthodontic clear aligners from different manufacturers: Alleo (AL); FlexiLigner (FL); F22 Aligner (F22); Invisalign® (INV); Lineo (LIN); Arc Angel (ARC), and Ortobel Aligner (OR). For each group, two aligners were immersed in artificial saliva for 7 days and stirred for 5 h/day, simulating the physiological teeth mechanical friction. After 7 days, the artificial saliva was filtered; then, filters were analyzed by Raman Microspectroscopy (RMS) and Scanning Electron Microscopy (SEM), respectively to chemically identify the polymeric matrix and to measure the number and size of the detected MPs. RMS spectra revealed that AL, FL, LIN, ARC, and OR aligners were composed by polyethylene terephthalate, while F22 and INV ones by polyurethane. SEM analysis showed that the highest number of MPs was found in ARC and the lowest in INV (p < 0.05). As regards MPs' size, no statistically significant difference was found among groups, with most MPs ranging from 5 to 20 µm. Noteworthy, a highly significant correlation (p < 0.0001) was highlighted between the distribution of MPs size and the different typologies of aligners. This in vitro study highlighted for the first time the detachment of MPs from clear aligners due to mechanical friction. This evidence may represent a great concern in the clinical practice since it could impact human general health.

Comparative Analysis of Skeletal Changes, Occlusal Changes, and Palatal Morphology in Children with Mild Class III Malocclusion Treated with Elastodontic Appliances and Bimaxillary Plates.

BACKGROUND: The aim of the present study was to compare the changes observed in children after the early treatment of mild class III malocclusion using bimaxillary removable plates supported by class III elastics and elastodontic devices. METHODS: Twenty children (mean age 7.6 ± 1.1 years) with signs of class III malocclusion were treated using by-maxillary plates (PG group) with class III elastics (10 subjects = mean age 7.9 ± 1.3 years) or using class III elastodontic devices (EG group) (10 subjects = mean age 7.4 ± 0.8 years). Digital models and lateral cephalograms were obtained before treatment (T0) and at the end of treatment (T1). The digital models were analyzed to assess occlusal changes and maxillary morphology using the surface-to-surface matching technique. Changes in cephalometric parameters were also analyzed. The data outcomes were statistically analyzed using the paired Student's t test for inter-timing assessments and the independent Student's t test for inter-group assessments. RESULTS: Both groups showed correction of class III malocclusions, with a significant increase in the ANB angle and the overjet (p < 0.05). Subjects in the PG group exhibited a greater reduction in the inter-incisal angle compared to the EG group (p < 0.05). The children in the EG group had a significantly lower percentage of palatal morphology matching between T0 and T1 compared to the PG group (p < 0.05), suggesting greater morphological changes in the palate. CONCLUSIONS: Elastodontic appliances (EAs) and bi-maxillary plates successfully correct class III malocclusions in children. However, elastodontic devices significantly improved the morphology of the palate, both in the transverse and anteroposterior directions.

Teledentistry: A bibliometric analysis of the scientific publication's trend.

Introduction: Teledentistry is a specialized area within telemedicine employs digital technology and telecommunications to remotely manage dental patients, offering care, advice, education, and treatment. The significance of teledentistry escalated during the COVID-19 pandemic. Objective: This study presents a bibliometric analysis of teledentistry, based on a retrospective search of the Scopus database. Materials and methods: The research utilized Bibliometrix and VOSviewer software. Results: Publications on teledentistry have shown a recent surge, particularly since 2020, attributed to the pandemic. Out of 369 articles, just 28 (7.5%) were single-authored, while most involved collaborative efforts. These articles were dispersed across 160 journals, with the Journal Of Telemedicine And Telecare, International Journal Of Environmental Research And Public Health, and Telemedicine And E-Health each publishing over 15 articles. Remarkably, 66% of the journals featured open-access content. The University of Western Australia emerged as the most prolific institution, with 12 publications, while the United States, Chile, and Brazil led in the number of published documents. Conclusions: The growing interest in teledentistry, mainly fueled by the pandemic, has promising implications for dental practice. Despite the existing limitations, it holds potential. This bibliometric analysis provides a comprehensive overview of the field and offers valuable quantitative insights for shaping future research and funding strategies, especially concerning protocol development and digital risk assessment.

Comparison of the Accuracy of Two Transfer Caps in Positional Transmission of Palatal Temporary Anchorage Devices: An In Vitro Study.

The aim of this study was to compare the positional information transfer accuracy of palatal temporary anchorage devices (TADs) of two different brands of transfer caps: PSM and Leone. Thirty plaster casts of maxillary dental arches were chosen for master models. A couple of Leone TADs were inserted in each master model. For each master model, two analysis models were created: using two transfer caps, Leone and PSM, the impressions were taken, the analogues were connected on the transfer caps, and the casts were poured. Using digital methods and equipment, such as a 3D scanner, a 3D analysis and a comparison of the accuracy of the two transfer caps in transferring the positional information of the TADs was then made. The data obtained were analyzed using the Mann-Whitney U-test at a significance level of α = 0.05. PSM transfer caps showed higher error frequency in almost all measurements. Only two measurements had a larger error in the analysis models made with Leone transfer caps. The Mann-Whitney U-test found a significant difference between the error levels of TADs found in the analysis models created with PSM transfer caps. Leone transfer caps showed greater reliability in TADs positional information transmission.

Fixed and removable orthodontic retainers, effects on periodontal health compared: A systematic review.

The aim of this systematic review is to analyze the properties of the different types of orthodontic retainers, identify their differences and define which type of device is most effective and less harmful to periodontal health. Methods: A literature search was carried out by a reviewer by consulting PubMed, Lilacs, Embase, Medline full text, Scopus, Web of Science, Cochrane library, and Science Direct electronic databases for biomedical and health literature as well as the grey literature and setting up the search from December 2010 without any restriction about articles languages. Results: The results showed that patients who wear retainers for a long period have significant differences in clinical parameters compared to patients without retainers. The type of retainer chosen also significantly influences the overall periodontal health of patients. Fixed retainers, both glass-fibre reinforced and steel wire retainers, proved to be the retainer type with the highest plaque and calculus accumulation values compared to removable retainers. In addition, among fixed retainers, glass-fibre reinforced retainers proved to be those that mostly promote the plaque and calculus accumulation in the application site. Conclusion: Fixed retainers are the best devices to maintain the alignment of mandibular anterior teeth in the long term. Among these devices, stainless steel lingual retainers, plain or braided, should remain the first choice. Although they are also susceptible to periodontal complications, their effect on periodontal health can be considered statistically insignificant if compared to glass-fibre reinforced retainers which, showing worse periodontal complications, should not be used.

Evaluation of the Loss of Strength, Resistance, and Elasticity in the Different Types of Intraoral Orthodontic Elastics (IOE): A Systematic Review of the Literature of In Vitro Studies.

BACKGROUND: Intraoral orthodontic elastics (IOE), typically referred to as rubber bands, are important tools for correcting malocclusion, and they are classified into latex and synthetic (elastomeric-based) elastics. They have different strengths and sizes, depending on their intended use, that provide clinicians with the ability to correct both anteroposterior and vertical discrepancies. Clinical use, together with saliva, alters the physical characteristics of both latex and synthetic elastics, causing declines in strength over time. AIM: The aim of the study was to assess, through a systematic review of in vitro studies, the properties of intraoral elastics. The primary goal was to evaluate how IOEs behave in terms of tension strength and duration. The secondary goal was to investigate the force loss during the first hours of wear. The tertiary goal was to assess how these forces decayed. MATERIALS AND METHODS: The following electronic databases were searched from December 2020 to April 2021: Medline Full Text, PubMed, Cochrane Clinical Trials Register, Science Direct, and Literature Review. Out of 8505 initial articles, 10 were selected for the systematic review. RESULTS: The force-degradation property was found in all types of IOEs. The loss of strength was directly proportional to time, with the highest value during the first 3 h after extension, regardless of the elastic band size and manufacturer. The forces generated by the latex bands were higher than in those of the elastomeric-based elastics, but they did not consistently correspond to the loads specified by the manufacturers. The retention forces in the latex IOEs were significantly higher than those in the nonlatex bands, suggesting that elastomeric-based bands need to be changed more frequently and at regular intervals throughout a 24 h period. CONCLUSION: This systematic review indicates that intraoral orthodontic elastics have the greatest loss of force during the first 3 h, that latex rubber bands have the highest strength during the first hour, that the forces generated are not always consistent with the manufacturer's specifications, and that nonlatex (elastomeric-based) IOEs need to be changed frequently and regularly during a 24-h cycle.

Performance of Rigid and Soft Transfer Templates Using Viscous and Fluid Resin-Based Composites in the Attachment Bonding Process of Clear Aligners.

OBJECTIVES: The study aims at assessing the accuracy of the process of attachment bonding in aligner treatments. The analysis leads to the error estimation in the faithful reproduction of master model attachments using two types of transfer templates and two light-curing resin-based composites usually used in orthodontics. METHODS: The authors have used two transfer templates made of two different materials. The first, named Leone-biocompatible thermoforming material hard/soft, has a lower Young's modulus and is labelled as soft, while the other, named Leone-biocompatible thermoforming material, is marked as rigid. The resin-based composites possess different mechanical and rheological properties. Specifically, Transbond™ XT Light Cure Paste Adhesive, 3M has a higher viscosity than the TetricEvoflow, Ivoclar Vivadent, a flowable nanohybrid composite. The authors attempt to estimate the performance ranking between the four possible couples obtained by combining the two light-curing resin-based composites and transfer templates. Each combination was repeated in six models and compared with twelve master models, resulting in 36 total samples. A 3-D laser scanner is used to generate a digital model of each model. The comparison between digital models is the base for a comparative assessment in terms of relative and absolute error. The relative error is estimated using scalar performance indicators ranging from 0 to 1, where 1 indicates the optimum matching. The absolute error estimated from the mean square error between the coordinates of each digital model yields the reproduction accuracy in micrometer. Furthermore, the authors attempted to assess the error distribution by evaluating the point-by-point difference between the digital models. RESULTS: This analysis aims at localizing the sources of error in the considered models. The use of Transbond™ XT Light Cure Paste Adhesive, 3M with a rigid transfer template is always associated with significant accuracy and minor dispersion. However, in a few instances, using the soft template or the flowable resin-based composite can lead to bad performances. Significance. The data processing bestowed the following performance ranking from the first with lower reproduction error to the last characterized by the worst performance: (1) attachments bonding with rigid template and Transbond™ XT Light Cure Paste Adhesive, 3M, (2) attachments bonding with soft template and Transbond™ XT Light Cure Paste Adhesive, 3M, (3) attachments bonding with rigid template and TetricEvoflow, Ivoclar Vivadent, and (4) attachments bonding with soft template and TetricEvoflow, Ivoclar Vivadent.

A comparison between stereophotogrammetry and smartphone structured light technology for three-dimensional face scanning.

OBJECTIVES: To compare three-dimensional facial scans obtained by stereophotogrammetry with two different applications for smartphone supporting the TrueDepth system, a structured light technology. MATERIALS AND METHODS: Facial scans of 40 different subjects were acquired with three different systems. The 3dMDtrio Stereophotogrammetry System (3dMD, Atlanta, Ga) was compared with a smartphone (iPhone Xs; Apple, Cupertino, Calif) equipped with the Bellus3D Face Application (version 1.6.11; Bellus3D Inc, Campbell, Calif) or Capture (version 1.2.5; Standard Cyborg Inc, San Francisco, Calif). Times of image acquisition and elaboration were recorded. The surface-to-surface deviation and the distance between 18 landmarks from 3dMD reference images to those acquired with Bellus3D or Capture were measured. RESULTS: Capturing and processing times with the smartphone applications were considerably longer than with the 3dMD system. The surface-to-surface deviation analysis between the Bellus3D and 3dMD showed an overlap percentage of 80.01% ± 5.92% and 56.62% ± 7.65% within the ranges of 1 mm and 0.5 mm discrepancy, respectively. Images from Capture showed an overlap percentage of 81.40% ± 9.59% and 56.45% ± 11.62% within the ranges of 1 mm and 0.5 mm, respectively. CONCLUSIONS: The face image acquisition with the 3dMD device is fast and accurate, but bulky and expensive. The new smartphone applications combined with the TrueDepth sensors show promising results. They need more accuracy from the operator and more compliance from the patient because of the increased acquisition time. Their greatest advantages are related to cost and portability.

Oral Alterations in Heritable Epidermolysis Bullosa: A Clinical Study and Literature Review.

Epidermolysis bullosa (EB) is a group of skin disorders with skin fragility characterized by blistering from minimal mechanical trauma with rupture at the dermoepidermal junction. There are four major classical heritable EB types, due to mutations in as many as 20 distinct genes: EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB), and Kindler EB (KEB). This study is aimed at reporting case series on patients (N = 8; males, n = 5 and females, n = 3, age range 12-68 years) affected by EB and performs a review of the literature on this topic. This group of disorders can affect oral soft and hard tissues in various ways, resulting in various effects including enamel hypoplasia, dental caries, microstomia, ankyloglossia, oral blistering, and ulcerations early-onset periodontal disease. From the sample results, it can be concluded that the clinical manifestation of EB patients is highly variable and very different in prognosis. Oral health deeply influences the quality of life of EB patients. Dental management is essential to prevent the aggravation of soft tissue damage and tooth loss and to improve the quality of life through prosthetic and restorative therapies. Dentists should consider the oral alterations of EB subtypes to perform a personalized approach to the patients' needs in a preventive and therapeutic point of view.

Elastodontic Devices in Orthodontics: An In-Vitro Study on Mechanical Deformation under Loading.

The purpose of the present study was to evaluate the mechanical resistance of elastodontic devices (ED): their maximum compression loads and plastic deformation under loading (percentage). An Instron universal machine (Model 3365, Instron, Industrial Product Group, Grove City, PA, USA) was employed with a 100 N load cell and with Bluehill software for loading analyses. Each device was submitted to a five-cycles test. The following ED were evaluated: A.M.C.O.P. (Micerium, Genova, Italy) in red color, in orange color, and in blue color; HealthyStart (Ortho-Tain, Winnetka, IL, USA), and T4K™ phase 1 (Myofunctional Research Co., Helensvale, Australia). During the five-cycles test, the Ortho-Tain device delivered the greatest compression load (7.56 N), with the lowest percentage of deformation (0.95%). For all devices, a slight plastic deformation of the material was registered, ranging from 0.95% to 1.75%. For the T4K device it was not possible to complete the five-cycles test. For all the analyzed ED, a slight plastic deformation under loading was registered, that in all cases can be considered clinically acceptable. Further studies are needed to test the appliances after clinical usage.