Periodontal health during clear aligners treatment: a systematic review

An index system for the clinical supervision of clear aligner in extraction patients based on the Delphi method and the analytic hierarchy process

BACKGROUND

Clinical supervision of clear aligner treatment in extraction patients is essential during the long process of follow-up period. However, there is insufficient clinical guidance available to define the key points of a standard examination for clinical supervision.

METHODS

An initial index system was constructed based on a comprehensive literature review. The final indexes to be used in the system were determined through Delphi process. Weightings for the final index system were determined using the Analytic Hierarchy Process (AHP), which required the development of a judgment matrix to assess the relative significance of each index through pairwise comparisons.

RESULTS

A tiered indexing system was created, consisting of two primary indexes, 10 secondary indexes, and 30 tertiary indexes. The expert authority coefficient (Cr) was 0.89 for the first round of consultation and 0.91 for the second round. The weighting values for the first-level indexes 'tooth movement' and 'dentofacial health' were 0.38215 and 0.61785, respectively, thus indicating that dentofacial health holds greater importance.

CONCLUSIONS

We integrated both qualitative and quantitative analyses to establish a novel index system for clinical supervision of clear aligner treatment in extraction patients to reduce the incidence of complications.

Incidence and risk factors of alveolar bone dehiscences and fenestrations after clear aligner therapy with Class II elastics: a retrospective study

BACKGROUND

In clear aligner therapy (CAT), Class II elastics are widely used to reinforce the anchorage during the distalization of upper molars, however, their association with alveolar bone dehiscences (ABDs) and fenestrations (ABFs) in the anterior region remains unclear. The aim of this research is to assess the incidence of ABDs/ABFs in adult patients undergoing non-extraction CAT with Class II elastics, and to explore risk factors associated with the occurrence of ABDs/ABFs.

METHODS

Thirty adult patients with Class II malocclusion who underwent non-extraction CAT with Class II intermaxillary elastics were enrolled in this study. Cone-beam computed tomography (CBCT) images were obtained before (T0) and immediately after (T1) CAT to assess the occurrence of ABDs/ABFs on the labial and lingual sides of anterior teeth. Chi-square tests were used to compare the incidence of ABDs/ABFs at T0 and T1, meanwhile, binary logistic regression was utilized to analyze the risk factors associated with ABDs/ABFs at T1.

RESULTS

On the labial side, the incidence of ABDs increased significantly in the mandibular central incisors (from 36.7 to 62.8%, P < 0.05), mandibular lateral incisors (from 36.7 to 70.0%, P < 0.05), mandibular canines (from 31.7 to 53.3%, P < 0.05) and maxillary canines (from 30.0 to 55.0%, P < 0.05). While on the lingual side, it increased significantly in the maxillary central incisors (from 1.7 to 23.3%, P < 0.05), lateral incisors (from 6.7 to 38.3%, P < 0.05), and canines (from 21.7 to 46.7%, P < 0.05). The incidence of ABFs only increased on the labial side of the maxillary canines and mandibular central incisors. The occurrence of maxillary ABDs was strongly associated with the crowding (OR = 1.318, P = 0.007), while the occurrence of the mandibular ABDs was significantly associated with root surface (labial vs. lingual, OR = 1.836, P = 0.008).

CONCLUSIONS

The incidence of ABDs/ABFs significantly increased after non-extraction CAT with Class II elastics in adults, especially on the labial root surface of the mandibular anterior teeth. Orthodontists should be well aware of the periodontal risks of CAT with Class II elastics.

Exploring the impact of orthodontic appliances on the oral microbiome and inflammatory parameters

BACKGROUND

The symbiotic relationship between the oral microbiome and the host immune system is a prerequisite of oral health. Disruptions to this system can be associated with the development of diseases like dental caries. Introducing orthodontic treatments, such as aligners and fixed appliances, might impact this microbial ecosystem. This study evaluated potential changes in salivary microbiome and the level of inflammatory marker myeloid-related protein 8/14 in patients undergoing orthodontic treatment with aligners or fixed appliances.

METHODS

Forty-eight patients were divided into two groups for treatment with fixed appliances or clear aligners. Unstimulated saliva samples were collected at baseline, three, and six months for microbiome analysis via 16 S rRNA sequencing and MRP-8/14 level measurement using ELISA.

RESULTS

Among 503 identified microbial species, no significant changes were noted in overall microbiome. A considerable increase of caries-relevant species could not be observed either. MRP-8/14 levels remained unchanged across treatments, indicating no alterations in the inflammatory level.

CONCLUSION

Orthodontic treatment with fixed or removable appliances does not significantly alter the salivary microbiome or influence inflammation, suggesting that these interventions are unlikely to affect oral health negatively.

Oral health in adolescents: periodontal inflammatory biomarkers during orthodontic clear aligner therapy

OBJECTIVES

This prospective study aimed to evaluate periodontal inflammation in adolescents undergoing orthodontic treatment with clear aligners (Invisalign® Teen, Align Technology, San Jose, CA, USA). Key objectives included assessing the presence of 11 periodontitis-associated marker bacteria, active matrix metalloproteinase-8 concentrations in sulcular fluid, and the influence of IL-1 polymorphism genotypes on periodontal health.

MATERIALS AND METHODS

Fifty adolescent patients (13.3 ± 1.8 years) with mixed and permanent dentition participated. Gingival crevicular fluid samples were analyzed at multiple time points: before, during, and one year after aligner treatment. Periodontal health was assessed using the Gingivitis Index and the Modified Quigley-Hein Index. Genotypic analysis of IL-1 polymorphism was also performed. Statistical analyses included mixed linear models and generalized linear models to explore correlations.

RESULTS

All combinations of IL-1 polymorphism genotypes were found in the sample. No significant increase in periodontal inflammation or aMMP-8 concentrations was observed over the treatment period. Marker bacteria from the red and orange-associated complexes remained at low levels, while significant changes occurred in the orange and green complexes, particularly Capnocytophaga spp. (p = 0.0042) and Fusobacterium spp. (p = 0.0365). GI correlated significantly with aMMP-8 levels (p = 0.0017), but no genotype effect on GI was observed. MQH showed associations with pathogens from the orange and green complexes, including Capnocytophaga spp. and Fusobacterium spp.

CONCLUSIONS

Clear aligner treatment in adolescents, including those with an unfavorable genotype, does not increase periodontal inflammation when accompanied by good oral hygiene.

CLINICAL RELEVANCE

Regular periodontal monitoring and hygiene reinforcement is important during orthodontic treatment, especially in adolescent patients.

EFFECTIVENESS OF CLEAR ORTHODONTIC ALIGNERS IN CORRECTING MALOCCLUSIONS: A SYSTEMATIC REVIEW AND META-ANALYSIS

OBJECTIVE

The purpose of this research was to assess the effectiveness of clear aligners in treating various types of malocclusions when compared to fixed orthodontic appliances.

METHODS AND QUALITY

The following databases were searched: EMBASE (Ovid), Medline (Ovid), the Cochrane Library, Latin America and the Caribbean Literature on Health Sciences (Lilacs), Web of Science and EBMR review until October 2024. Additionally, Google scholar, PubMed were also searched for completion for including all relevant articles. No restrictions were placed on language or publication date, and only randomized controlled trials (RCTs) were included in this review. Evaluation of the potential for bias in randomized controlled trials (RCTs) was carried out with the use of the revised Cochrane Risk of Bias instrument (ROB tool 2). The primary outcome was the treatment accuracy of clear aligners vs fixed appliances and included orthodontic tooth movement in terms of anteroposterior discrepancy, transverse discrepancy, vertical discrepancy and overjet. The secondary outcomes included the effectiveness of treatment, such as duration of treatment, periodontal health, root resorption and patient satisfaction. Available data was meta-synthesized using Review Manager 5.4.

RESULTS

About 21 RCT studies were selected from a total of 600 records and involved 970 participants. All 21 studies included a comparison of the effectiveness of clear aligners vs fixed appliances. About 3 of the studies were assessed to be at high risk of bias, whilst 14 of the studies were assessed to be at unclear risk of bias, and only 1 study was found to be at low risk of bias. Based on the primary outcome, there was no significant difference in the ABO objective grading scores, Little Irregularity Index and PAR scores between the fixed appliances and clear aligner treatments. Meta-analysis was only possible for secondary outcomes. The scores for plaque index (MD = -0.76, 95% CI, -1.14 to - 0.38, P = .00001), gingival index (MD = -0.61, 95% CI, -0.78 to - 0.44, P = .00001) and bleeding index (MD = -0.71, 95% CI, -0.92 to - 0.49, P < .0001) were significantly lower in clear aligners when compared to the fixed appliances. The patients quality of life at 6 months was significantly better for clear aligners compared with fixed appliances (MD = -4.37, 95% CI, -6.93 to -1.80, P < .0001). Clear aligners also appeared to have a better outcome for chairside time, pain and root resorption.

CONCLUSION

The overall quality of evidence from the included studies was low. Both clear aligners and fixed appliances worked well in treating simple malocclusions treated on a nonextraction basis. There was no significant difference in the ABO Objective Grading System, Little Irregularity index and PAR scores between the clear aligner and fixed appliance groups. There was low quality evidence available in favor of clear aligners for periodontal health and moderate quality evidence in favor of clear aligners for quality of life. More high-quality studies evaluating clear aligner treatment for treating complex malocclusions are required.

A comparison of the alterations of oral microbiome with fixed orthodontic therapy and clear aligners: a systematic review

Aim

The oral microbiome plays a fundamental role in maintaining homeostasis of the oral cavity. In the last decade there has been an increasing use of clear aligners, which guarantee aesthetics and comfort for the patient. The aim of this work is to conduct a systematic review regarding the alterations in bacterial flora and oral health with aligner and fixed orthodontic therapy.

Design

A systematic review was conducted following the PRISMA Statement. Using the search strategy "(clear aligners OR Invisalign) AND (fixed therapy OR fixed orthodont * therapy) NOT (thermoplastic retainers) AND (oral microbiome OR oral microbiota * OR oral microbiology * OR oral health)", in the main scientific databases. Two scales were applied to assess the quality of scientific evidence: ROBINS-I and RoB 2.

Results

A total of 484 articles emerged of which 9 met our inclusion/exclusion criteria. Afterwards the application of the rating scales, 1 article was found to be at low risk of bias, 6 at moderate and 2 at serious risk of bias.

Conclusion

Both therapies cause an alteration of the oral microbiome, but the changes induced by the aligners seem to be compatible with a better oral health compared to fixed appliances.

Clear Aligner Treatment: Indications, Advantages, and Adverse Effects-A Systematic Review

Background/Objectives: Clear aligner treatment (CAT) has gained interest among clinicians as well as among patients. The aim of the present study was to systematically review the literature regarding current viewpoints on indications, contraindications, advantages, disadvantages, and adverse effects in CAT. Methods: A search was performed in the PubMed and Embase databases, yielding 18 studies eligible for inclusion. Results: Current indications for CAT are mild to moderate malocclusions. Severe malocclusions with impactions or severe craniofacial skeletal deviations are contraindications. The advantages were oral hygiene and oral health as the most common, and disadvantages of CAT have been noted by several studies, including CAT still being inferior to fixed appliance treatment (FAT) in all orthodontic movements. Adverse effects were potential health risks due to microplastics and a decrease in condyle bone volume. Conclusions: No firm conclusions can be drawn regarding indications for CAT except for mild to moderate malocclusion. Severe malocclusions with impactions or severe craniofacial skeletal deviations are considered contraindications. In more complex cases, CAT is still considered inferior to FAT, although CAT contains advantages. There are disadvantages in CAT which clinicians should consider when choosing a type of orthodontic appliance for treating specific malocclusions. Only a few adverse effects in CAT were presented by the included studies. More high-quality research is needed regarding indications and contraindications for CAT.

Biomechanical and Biological Multidisciplinary Strategies in the Orthodontic Treatment of Patients with Periodontal Diseases: A Review of the Literature

Orthodontic treatment aims to correct malocclusions and ensure the overall health and stability of the periodontium. The relationship between orthodontic therapy and periodontal health is intricate and multifaceted, and a comprehensive approach is often required to achieve optimal outcomes. Firstly, this article delves into the impact of orthodontic mechanics on periodontal tissues, emphasizing the importance of minimizing iatrogenic effects such as root resorption and gingival recession. Understanding the biomechanical principles allows for the development of treatment plans that mitigate these risks while achieving the desired tooth movement. Effective communication and coordinated treatment protocols are essential for managing periodontal issues before, during, and after orthodontic intervention. To optimize outcomes, periodontal considerations such as gingival biotype, attachment levels, and bone support must be integrated into treatment planning. Additionally, adjunctive periodontal therapies such as selective alveolar decortication and regenerative procedures are explored as valuable tools to enhance periodontal support and optimize treatment outcomes. This narrative review explores strategies to attain periodontal goals in orthodontic patients, thereby facilitating successful treatment. Furthermore, the review examines the role of interdisciplinary collaborations between orthodontists and periodontists. In conclusion, achieving periodontal goals in orthodontic patients requires a comprehensive approach that addresses biomechanical principles, interdisciplinary collaboration, patient education, and adjunctive periodontal therapies. By integrating periodontal considerations into orthodontic treatment planning and execution, clinicians can ensure straight teeth and a healthy and stable periodontium, ultimately leading to successful treatment outcomes and long-term oral health.

Effects of clear aligners treatment in growing patients: a systematic review

Introduction

In recent years, the use of Clear aligners (CA) has been diffused among children and adolescents. This systematic review aimed to summarize the literature regarding the effects of CA therapy in growing patients, including dentoalveolar and skeletal effects, periodontal changes, and quality of life measurements.

Methods

An electronic search on four databases was performed until September 2023, and studies including patients <18 years, treated with CA were selected. Studies with less than 10 patients and in vitro/laboratory studies were excluded. Study selection, data extraction, and risk of bias assessment were independently performed by two reviewers. The "Risk of Bias 2" (RoB 2) and the "Risk of Bias in Non-randomized Studies of Interventions" (ROBINS-I) tools were applied to assess the methodological quality of the included studies. Due to the heterogeneity in methodologies and outcomes encountered in the included studies, a qualitative synthesis of the results was provided.

Results and conclusions

The search resulted in 32 papers (3 RCTs), with sample sizes ranging between 15 and 113. The overall risk of bias in the RCT was low, while the risk of bias in the non-RCT ranged between moderate and serious for most of the included studies. Dentoskeletal and periodontal effects were the most frequently reported outcomes. The most common comparison group was multibracket fixed therapy, while only 5 studies had an untreated control group. Significant changes in the transversal maxillary arch width after treatment with CA were reported in some studies. However, while dentoalveolar effects have been reported consistently, controversial findings were found regarding the changes in skeletal bases after treatment with CA. Concerning the results on the sagittal plane, the current literature does not support the effectiveness of CA with mandibular advancement features in correcting dentoskeletal Class II, compared to traditional functional orthopedic appliances. In the short-term evaluation, periodontal variables and bacterial levels seemed to be better controlled during CA therapy, compared to the fixed multibracket therapy. With regard to quality of life measurements, there are inconsistent findings to support differences between CA therapy and fixed multibracket appliances. Nevertheless, additional high-quality studies are required to formulate more reliable conclusions.

Systematic Review Registration

https://osf.io/wmerq.

The Effect of storybook use in pediatric health services on children's fear and anxiety levels: A meta-analysis study

BACKGROUND

Invasive procedures are commonly used in pediatric healthcare, and storybooks can be used as an adjunct analgesic method.

OBJECTIVES

This study was conducted to evaluate the effectiveness of using storybooks as a distraction technique to reduce fear and anxiety in pediatric healthcare. This study was conducted with the aim of revealing the level of effect of storybook use on children's fear and anxiety level in pediatric health services.

METHODS

For this meta-analysis study, the studies were obtained by searching PubMed, Web of Scıence, Scopus, EBSCOhost, Google Scholar and YÖK Thesis Center databases in April-June 2024 without any year limitation. After the reviews, 15 studies were included in the study. The data were synthesized by meta-analysis and narrative methods.

FINDINGS

In this meta-analysis, it was found that storybook use in pediatric health services was effective on children's anxiety (SMD: -4.412, 95 % CI: -7.727 to -1.097; Z = -2.608, p = 0.009; I2 = 99.890 %) and fear (SMD: -1.13, 95 % CI: -1.71 to -0.54; Z = -3.78, p = 0.000; I2 = 83.065 %) levels. In addition, it was determined that the characteristics of the intervention group, age group, the characteristics and content of the storybook, the duration of the intervention and the time of the intervention played a role in the effectiveness of the storybook use intervention in pediatric health services on children's anxiety and fear levels.

CONCLUSION

The use of story books in children's health services reduces the level of fear and anxiety in children.

Comparison of microbial adhesion and biofilm formation on different orthodontic aligners

INTRODUCTION

This study aimed to compare and evaluate time-dependent biofilm formation and microbial adhesion on 6 different clear aligner systems: Invisalign (Align Technology, San Jose, Calif), Clarity (3M ESPE Maplewood, Minn), ClearCorrect (Institut Straumann AG, Basel, Switzerland), Smartee (Smartee Denti-Technology, Shanghai, China), Orthero (Orthero, Istanbul, Turkey) and Graphy (Graphy Inc, Seoul, South Korea).

METHODS

Streptococcus mutans (ATCC 25175) and Lactobacillus acidophilus (ATCC 4356) were used to evaluate the microbial adhesion and biofilm formation on orthodontic clear aligners at the 0, 24, 48, 72, 96, 120, 168, and 240 hours. Two-way repeated measures analysis of variance (Greenhouse-Geisser) test and post-hoc Bonferroni T2 tests were used for statistical evaluation. The statistical significance level was set at P <0.05.

RESULTS

It was found that more bacterial formation occurred on ClearCorrect than on Smartee at 120, 168, and 240 hours (P <0.05). It was observed more biofilm formation at 168 hours on Graphy than on Smartee (P <0.05). It was found that S mutans + L acidophilus formed more biofilm at 120 and 168 hours on Graphy than on Invisalign (P <0.05).

CONCLUSIONS

Elevated biofilm formation across all materials carries substantial clinical implications. Orthodontists and patients should remain aware of the increased risk of microbial colonization with extended aligner usage.

Multidisciplinary Approach to Smile Design of a Patient With Osteogenesis Imperfecta With Clear Aligners and Prosthetic Restorations

Osteogenesis imperfecta (OI) is an autosomal dominant disease that affects the teeth and the musculoskeletal system. Orthodontic treatment in OI patients may be risky due to the fragility of dental hard tissues. Clear aligners may be considered a suitable orthodontic treatment method for these patients. A 30-year-old female OI patient with Angle Class I malocclusion, open bite, and crowding underwent prosthetic treatment after 15 months of clear aligner orthodontic treatment. Aesthetic rehabilitation was achieved with clear aligner treatment and prosthetic restorations. It is possible to obtain more aesthetic results with orthodontic treatments before prosthetic restorations in the oral rehabilitation of patients with skeletal and dental malocclusions. In orthodontic treatments in adult patients with systemic diseases, the use of clear aligners both minimizes the risk and provides a more comfortable process.

Three-dimensional finite element analysis of retracting pathological migration of the right upper central incisor with a clear aligner

We aimed to explore the best orthodontic step distance of the right upper central incisor with mild, moderate, and severe pathological displacement achieved via a clear aligner. Three-dimensional models of maxilla-tooth-periodontal ligament clear aligner of the right upper central incisors with five different steps of 0.1, 0.125, 0.15, 0.165, 0.25 mm and three different alveolar bone heights were established via finite element analysis. We analysed the changing trends in initial displacement, the periodontal ligament, the alveolar bone, and apical stress of right upper central incisor. In the process of retraction, the right upper central incisor a movement trend of the crown deviating from the distal root to the mesial, and with the decrease of the height of the alveolar bone and the increase of the displacement, the crown would appear distal labial torsion with a deepening trend of vertical overlay.The maximum stress distribution of the periodontal ligament and alveolar bone showed a positive correlation. The overall stress distribution of the periodontal ligament and apical stress increased with decrease of alveolar bone height and the increase of alveolar bone displacement. In patients with mild, moderate, and severe pathological displacement of the right upper central incisor, the best step distance of anterior tooth retraction is 0.165, 0.15, and 0.125 mm, respectively.

Comparative Study of Periodontal Health in Patients with Fixed Braces Versus Clear Aligners

Background

Orthodontic therapy is often used to cure dental malocclusions; however, since orthodontic equipment is difficult to keep clean, it might have an adverse effect on periodontal health. Clear aligners and fixed braces are two common orthodontic treatments.

Materials and Methods

In this research, 100 patients receiving orthodontic treatment at a dental clinic ranged in age from 18 to 35. Two sets of patients were created: 50 with transparent aligners and 50 with fixed braces. At baseline, three months, and six months, periodontal health was evaluated using the plaque index (PI), gingival index (GI), and probing depth (PD). Both groups received advice on oral hygiene. SPSS software was used for data analysis, with a significance level of P < 0.05 for statistical analysis.

Results

PI, GI, and PD did not vary significantly between the two groups at baseline (P > 0.05). PI (2.3 ± 0.4) and GI (1.8 ± 0.3) in the fixed braces group were significantly higher after three months than in the clear aligners group (PI: 1.5 ± 0.3, GI: 1.2 ± 0.2, P < 0.05). At six months, the group using fixed braces had a substantially higher PD (3.5 ± 0.5 mm) than the group wearing transparent aligners (2.8 ± 0.4 mm, P < 0.05). Throughout the course of the trial, the group using transparent aligners had greater periodontal health.

Conclusion

In comparison with patients wearing fixed braces, individuals using transparent aligners showed improved periodontal health, as seen by decreased levels of plaque buildup, gingival inflammation, and probing depth. For individuals who are worried about their periodontal health while undergoing orthodontic treatment, clear aligners could be a better choice.

Effectiveness of palatal anchorage device (PAD) for maxillary anterior retraction with clear aligners using finite element study

The palatal anchorage device (PAD) is commonly used in fixed appliance for anchorage, but the biomechanics of PAD in patients treated with clear aligners(CAs)remains poorly understood, especially in its elastic mode and force magnitude. This study aimed to assess the biomechanical effects of using PAD for retraction during clear aligner treatment (CAT) with the extraction of two maxillary first premolars. Four finite element models were created: (1) Incisors retraction (IR) with active contraction of the clear aligner only; (2) IR with PAD using different forces (50,75,100 g) or not; (3) PAD without IR (forces of 50,75,100 g), and (4) Different elastic directions (D1, D2, D3) from aligner to PAD without IR. IR caused lingual tipping and extrusion of the central incisors, as well as mesial and buccal tipping of the first molar. PAD during IR provided strong anchorage for the first molar, with elastics slightly increasing the lingual tipping and extrusion of the central incisors. Elastics applied to the U-shaped arch led to central incisor intrusion and reduced lingual retraction. The highest stress was observed on the mesial attachment of the canine. PAD effectively reinforced posterior anchorage in CAT, while anterior positioning facilitated anterior teeth intrusion. The biomechanical importance of the canine's mesial attachments in maxillary teeth treatment planning was highlighted.

Incidence, severity, and risk factors for white spot lesions in adolescent patients treated with clear aligners

OBJECTIVES

This study was aimed to clarify the incidence, severity, and clinical risk factors for white spot lesions (WSLs) in adolescent patients treated with clear aligners.

METHODS

Pre-treatment and post-treatment intraoral photographs of 203 adolescent patients undergoing clear aligner therapy were retrospectively evaluated to assess the occurrence and severity of WSLs. Information on patients' general oral condition and orthodontic treatment was collected from clinical medical documents, retrospective questionnaires, and ClinCheck® software. Independent risk factors and model performance were determined by multivariate logistic regression and receiver operating characteristic curve analysis.

RESULTS

Thirty-five percent of adolescent patients developed WSLs during clear aligner treatment. Logistic regression analysis revealed that the presence of WSLs before treatment (OR 2.484, 95% CI 1.245-4.957), frequency of drinking carbonated beverages (OR 1.508, 95% CI 1.045-2.177), and number of anterior attachments (OR 2.192, 95% CI 1.502-3.198) were risk factors for the occurrence of WSLs in adolescent patients treated with clear aligners (P < .05), whereas the number of times they brushed each day (OR 0.656, 95% CI 0.454-0.947) and frequency of aligner cleaning after eating while wearing them (OR 0.611, 95% CI 0.433-0.861) were protective factors against WSLs (P < .05).

CONCLUSIONS

The incidence of WSLs was high in adolescent patients treated with clear aligners. Few brushings each day, pre-treatment WSLs, a high frequency of drinking carbonated beverages, a low frequency of aligner cleaning after eating while wearing them, and a high number of anterior attachments are strongly associated with the development of WSLs in adolescent patients treated with clear aligners.

Prospects for 3D-printing of clear aligners—a narrative review

Clear aligner therapy is a rapidly developing orthodontic treatment. 3D-printing technology, which enables the creation of complex geometric structures with high precision, has been used in dentistry. This article aims to summarize the various aspects of 3D-printing clear aligners and give an outlook on their future development. The traditional thermoforming technology is introduced and the principle and application of 3D-printed clear aligners and materials are introduced, as well as the application prospects of 3D-printed clear aligners. According to PRISMA statement, the relevant literature of 3D-printing clear aligner was searched in PubMed, Web of Science, Embase and other databases. We searched the related words in the MESH database and then carried out advanced searches. We read systematic review and conference papers to find the articles related to the subject and manually added and excluded articles by reading the title and abstract. The production of clear aligners combines computer-aided 3D analysis, personalized design and digital molding technology. The thickness and edges of the 3D-printed clear aligner can be digitally controlled, which allows appliance more efficiently fitted. Presently, the array of clear resins suitable for 3D-printing include photo polymeric clear methacrylate-based resin (Dental LT) (Form Labs, Somerville, Mass), aliphatic vinyl ester-polyurethane polymer (Tera Harz TC-85) (Graphy, Seoul, South Korea). They all have good biocompatibility. But no such material is currently approved on the market. Developing biocompatible resins and further improving the material’s mechanical properties will be critical for the combination of 3D-printing and clear aligners. However, the literature on 3D-printed clear aligners is limited and lacks clinical application. Further in vivo and in vitro tests, as well as additional exploration in conjunction with corresponding cytological tests, are required for the research on available materials and machinery for 3D-printing clear aligners.

The oral microbiota and periodontal health in orthodontic patients

The oral microbiota develops within the first 2 years of childhood and becomes distinct from the parents by 4 years-of-age. The oral microbiota plays an important role in the overall health/symbiosis of the individual. Deviations from the state of symbiosis leads to dysbiosis and an increased risk of pathogenicity. Deviations can occur not only from daily life activities but also from orthodontic interventions. Orthodontic appliances are formed from a variety of biomaterials. Once inserted, they serve as a breeding ground for microbial attachment, not only from new surface areas and crevices but also from material physicochemical interactions different than in the symbiotic state. Individuals undergoing orthodontic treatment show, compared with untreated people, qualitative and quantitative differences in activity within the oral microbiota, induced by increased retention of supra- and subgingival microbial plaque throughout the treatment period. These changes are at the root of the main undesirable effects, such as gingivitis, white spot lesions (WSL), and more severe caries lesions. Notably, the oral microbiota profile in the first weeks of orthodontic intervention might be a valuable indicator to predict and identify higher-risk individuals with respect to periodontal health and caries risk within an otherwise healthy population. Antimicrobial coatings have been used to dissuade microbes from adhering to the biomaterial; however, they disrupt the host microbiota, and several bacterial strains have become resistant. Smart biomaterials that can reduce the antimicrobial load preventing microbial adhesion to orthodontic appliances have shown promising results, but their complexity has kept many solutions from reaching the clinic. 3D printing technology provides opportunities for complex chemical syntheses to be performed uniformly, reducing the cost of producing smart biomaterials giving hope that they may reach the clinic in the near future. The purpose of this review is to emphasize the importance of the oral microbiota during orthodontic therapy and to use innovative technologies to better maintain its healthy balance during surgical procedures.

Clear aligner's adverse effects: A systematic review protocol

With the growing popularity of clear aligners, more patients have chosen to use them instead of traditional orthodontic braces to correct their malocclusions. Clear aligners offer distinct advantages over conventional fixed braces, such as limited aesthetic impact, the convenience of easily removing them for meals, improved accessibility for brushing and flossing, and a treatment approach that avoids the use of metal, minimizing potential irritation to the cheeks and gums. Manufacturers point out a disadvantage that can be administered in this type of treatment. Still, to our knowledge, a comprehensive review of the published literature assessing the adverse/negative effects of clear aligners has not yet been conducted. A systematic review, with or without meta-analysis, will be performed. The inclusion criteria will be studies involving individuals using clear aligners and reporting potential adverse/negative effects during or after treatment. No restrictions about time or language will be applied. The studies screening will be conducted in two stages. Two independent reviewers will initially evaluate the title and abstract under the eligibility criteria. Subsequently, the same two reviewers will examine the articles' full text in-depth. The results will be synthesized in the form of a narrative description and incorporate a meta-analysis if justified. Furthermore, we will present details regarding the sample characteristics, intervention, study objectives, methodologies employed, and primary findings. This study aims to investigate the potential adverse effects and their frequency among orthodontic patients wearing clear aligners. Moreover, the outcomes of this review have the potential to illuminate specific inherent limitations of aligner therapy as a comprehensive orthodontic approach.

The Influence of Orthodontic Treatment on Periodontal Health between Challenge and Synergy: A Narrative Review

By correctly repositioning teeth, orthodontic therapy improves both the function and appearance of an occlusion. The relationship between teeth and the tissues that surround and support them significantly influences these alterations. With ever more adults seeking orthodontic care, orthodontists are increasingly seeing patients with periodontal issues. Concerns about the patient's appearance, such as uneven gingival margins or functional issues caused by inflammatory periodontal diseases, should be accounted for when designing orthodontic treatment plans. Furthermore, orthodontics may increase the chances of saving and recovering a degraded dentition in cases of severe periodontitis. Today, general dentists, dontists, and orthodontists play integrative roles that enable them to achieve the best possible results for their patients. This review will improve the results of interdisciplinary treatments and increase cooperation between dental specialists by drawing attention to the essential connection between orthodontics and periodontics in regular clinical practice.

Predictability of Orthodontic Space Closure Using Invisalign Clear Aligners: A Retrospective Study

Introduction Clear aligners have demonstrated success in achieving complex tooth movements. However, orthodontists have faced challenges related to the predictability of clear aligners. This retrospective study aimed to assess the predictability of ClinCheck® accuracy in space closure before and after Invisalign® treatment and to identify factors associated with the need for refinement. Methods Patient records from one private clinic in Makkah, Saudi Arabia, were analyzed, and a sample of 55 adult patients who had spacing and underwent Invisalign treatment were included. Data on demographic and orthodontic variables were collected, and a chi-square test was conducted to examine the association between the requirement for refinement and demographic as well as clinical/orthodontic factors. Furthermore, the initial and final space measurements were compared using paired t-tests across various demographic and clinical/orthodontic variables. Results After completing the treatment, 70.9% (N=39) of the cases did not require any orthodontic refinement. The mean final space measurement was higher for males compared to females (0.7 mm and 0.4 mm, respectively), individuals who received treatment in the upper compared to lower arch (0.5 and 0.4 mm, respectively), those with moderate compared to mild spacing (0.5 and 0.1 mm, respectively), and those with class III compared to class I Angle classification (0.9 and 0.3 mm, respectively). Additionally, patients with severe spacing had a significantly higher probability of requiring refinement compared to patients with mild spacing (adjusted odds ratio = 20.9; p < 0.05). Conclusion The study emphasizes the significance of careful patient selection and treatment planning, suggesting that orthodontists should consider overcorrecting in space closure when using clear aligners, especially in cases with more significant spacing.

Comparison of Mechanical Behavior of Clear Aligner and Rapid Palatal Expander on Transverse Plane: An In Vitro Study

(1) Background: This study aims to investigate, within a controlled laboratory environment, the magnitude of the transversal load and the force decay over time produced by clear aligners in comparison to a Rapid Palatal Expander (RPE). (2) Methods: Resin models of a dental maxillary arch, additively manufactured from an intraoral scan, were inserted in a testing machine with uniaxial load cells to measure the force trend over time expressed by RPE and clear aligners. The mechanical load was recorded during a certain timeframe for both appliances. (3) Results: The force expressed by the RPE ranged from 30 to 50 N for each activation, decreasing with a nonlinear pattern over time. The force expressed by the clear aligner ranged from 3 to 5 N, decreasing with a linear pattern over time. In contrast, the force generated by the clear aligner fell within the range of 3 to 5 N, showing a linear reduction in force magnitude over the observed period of time. (4) Conclusions: The RPE exerted a force magnitude approximately ten times greater than that generated by clear aligners. Nevertheless, it is essential to acknowledge that the oral environment can significantly influence these results. These limitations underscore the need for caution when applying these findings to clinical settings.

Comparison of the accuracy of three interproximal reduction methods used in clear aligner treatment

OBJECTIVES

To comparatively assess 3 interproximal reduction (IPR) methods used in clear aligner treatment with regard to accuracy, and patient perception of discomfort and anxiety.

MATERIALS AND METHODS

A total of 42 patients, treated with the Invisalign® system, were included in this prospective trial and received one of the following IPR methods: hand-operated abrasive strips (group 1; 14 patients, 150 teeth), motor-driven 3/4 oscillating segmental discs (group 2; 14 patients, 134 teeth), or motor-driven abrasive strips (group 3; 14 patients, 133 teeth). Accuracy was evaluated using the difference between planned and executed IPR. Anxiety and discomfort levels experienced by the patients were evaluated using a questionnaire of 17 questions.

RESULTS

The accuracy of IPR was high in groups 2 and 3; however, it was low in group 1 with the executed IPR significantly less than the planned amount. On quadrant-level, executed IPR was significantly less in the upper left quadrant in group 1, and significantly more in the upper right quadrant in group 2. The difference between planned IPR and executed IPR was significant for teeth 11, 21, 32, 33, and 43 in group 1, indicating deficiency. The average difference between planned IPR and executed IPR was 0.08 mm for group 1, 0.09 mm for group 2, and 0.1 mm for group 3. Anxiety and discomfort levels did not differ between the methods, but a negative correlation was observed between age and discomfort and anxiety levels.

CONCLUSIONS

The overall accuracy of the 2 motor-driven IPR methods was found to be better than the hand-operated system. Maxillary central incisors and mandibular canines were more prone to IPR deficiency when hand-operated abrasive strips were utilized. Patients were similarly comfortable with all 3 methods, and discomfort and anxiety levels decreased with age.

CLINICAL RELEVANCE

Motor-driven methods have proven to be more effective when compared to the hand-operated ones by means of precision, speed, and patient comfort. If the clinician favors a hand-operated method, it may be advised to perform slightly more IPR especially on mandibular canines and maxillary central incisors.

The effect of passive clear aligners on masticatory muscle activity in adults with different levels of oral parafunction

BACKGROUND

There is limited knowledge of the possible side-effects of clear aligners on jaw function.

OBJECTIVES

To determine the short-term effect of passive clear aligners (PCAs) on masticatory muscle activity (MMA), occlusal discomfort (OD) and temporomandibular disorder (TMD) symptoms in adults with different levels of self-reported oral parafunction.

MATERIALS AND METHODS

Participants were screened for oral parafunctional behaviours using the oral behavioural checklist. Respondents in ≥85th and ≤15th percentiles were invited to participate and allocated to a high (HPF: N = 15) or low (lower parafunction [LPF]: N = 16) parafunction group. Participants underwent a TMD clinical examination; somatisation and somatosensory amplification were assessed by questionnaires; OD and stress were assessed by visual analogue scales. While wearing PCAs, awake-time MMA was assessed three times over 9 days using a wearable electromyography device, along with OD, stress and TMD symptoms.

RESULTS

The wearing of PCAs was associated with a significant decrease in mean contraction episode amplitude in both groups (p = 0.003). OD levels increased and remained raised in all participants after insertion of the PCAs (p < 0.001), more so in the HPF group (p = 0.048). The HPF group had higher somatisation scores (p = 0.006) and reported more TMD symptoms at all time points (p ≤ 0.004). No significant changes in stress or TMD symptoms were found in either group during the study period.

CONCLUSIONS

PCAs were associated with a decrease in MMA in all participants. HPF individuals had greater somatisation and reported greater discomfort when wearing PCAs than LPF individuals.

Periodontal health status, oral microbiome, white-spot lesions and oral health related to quality of life-clear aligners versus fixed appliances: A systematic review, meta-analysis and meta-regression

Objective

: Assess and evaluate the different indicators of oral health-related quality of life (OHRQoL) among patients treated with clear aligners (CAs) versus those treated with conventional fixed orthodontics (FAs).

Methods

: An electronic search was performed on the database is Web of Science, Scopus, and Embase databases. Randomized and non-randomized control trials, cross-sectional, prospective cohort and retrospective trials were included. Quality was assessed with risk of bias tool and risk of bias in non-randomised studies. Meta-analyses were performed with random effects models, estimating the standardized and non-standardized mean differences, odds ratio and risk ratio as the measure of effect. The effect on time was determined using a meta-regression model.

Results

: Thirty one articles were included in the qualitative synthesis and 17 in the meta-analysis. CAs had a significantly lower negative impact on QoL, with an "important" effect size, while the influence of time was not significant. Periodontal indicators plaque index (PI), gingival index (GI), probing depth (PD), and bleeding on probing show significantly better values in patients treated with CAs, with moderate to large effect sizes. PI and GI have a significant tendency to improve over time. In microbiological indicators, CAs present a lower biofilm mass without differences in the percentage of patients with high counts of Streptococcus mutans and Lactobacilli bacteria. The risk of white spot lesion onset is ten times lower in carriers of CAs.

Conclusions

: Patients wearing CAs show better periodontal indicators, less risk of white spot development, less biofilm mass and a better QoL than patients with FAs.

Impact of Clear Aligners on Oral Health and Oral Microbiome During Orthodontic Treatment

The demand for clear aligners has risen over the past decade because they satisfy patients' desire for less noticeable and more comfortable orthodontic appliances. Because clear aligners are increasingly used in orthodontics, there is a big push to learn more about the physiologic and microbial changes that occur during treatment. The present work highlighted further links between clear aligners and changes in oral health and the oral microbiome and provided plaque control methods for clear aligner trays. Existing literature revealed that clear aligners have no significant influence on the structure of the oral microbiome during orthodontic therapy. Clear aligner treatment demonstrated promising results in terms of controlling plaque index, gingival health, and the prevalence of white spot lesions. Nevertheless, grooves, ridges, microcracks, and abrasions on the aligner surface would provide a prime environment for bacterial adherence and the development of plaque biofilms. A combination of mechanical and chemical methods seems to be a successful approach for removing plaque biofilm from aligners whilst also preventing pigment adsorption.

White spot lesions, plaque accumulation and salivary caries-associated bacteria in clear aligners compared to fixed orthodontic treatment. A systematic review and meta- analysis

OBJECTIVE

To analyse the available evidence regarding the incidence and severity of white spot lesions (WSLs), plaque accumulation and salivary caries-associated bacteria(SCB) in clear aligners (CA) verses conventional fixed (CF) orthodontic appliances.

METHODS

Electronic searches of MEDLINE, Scopus, Embase, Google Scholar, Clinical trial registry, OpenGrey and ProQuest were done for all relevant studies. Eligibility criteria were; Randomized Controlled Trials and Non-Randomized Studies that compared the incidence and severity of WSLs, plaque accumulation and SCB between CA and CF appliances in patients undergoing orthodontic treatment. The risk of bias(ROB) and certainty of evidence was assessed independently by two reviewers using Cochrane's ROB and GRADEpro, respectively. Standardized mean difference (SMD) was used to estimate the effect size using STATA 17 software.

RESULTS

A total of 14 studies met the eligibility criteria, and eight were suitable for meta-analysis. The qualitative results showed lower incidence and severity of WSLs, plaque accumulation, and SCB in CA group compared to CF appliances. The pooled results showed significantly lower plaque accumulation(SMD - 1.58;95%CI:-2.57,0.58;p = 0.002) in CA compared to CF appliances.

CONCLUSIONS

A moderate-quality evidence reveals less plaque accumulation and less SCB in CA, which might be related to the reduced incidence and severity of WSLs associated with CA when compared with CF appliances. However, the results of the present study should be interpreted with caution given the high ROB among some of the included studies as well as the marked heterogeneity across the studies.

CLINICAL RELEVANCE

For patients who can be treated with either CA or CF appliances, CA may be a better choice concerning oral health.

REGISTRATION

Open Science Framework (DOI: https://doi.org/10.17605/osf.io/kcpvb ).

Clinical outcomes of arch expansion with Invisalign: a systematic review

OBJECTIVE

This study aims to assess the scientific evidence regarding the clinical outcomes of Invisalign therapy in controlling orthodontic tooth movement.

MATERIALS AND METHODS

An electronic search was conducted on PubMed, Cochrane Library, Web of Science, Embase, and Scopus from November 2015 to November 2022 to identify relevant articles. Methodological shortcomings were highlighted, and an evaluation of the quality of the included studies was completed using the Risk of Bias in Non-randomized Studies of Interventions (ROBINS-I) tool.

RESULTS

Fifteen non-randomized controlled trials were included in the analysis. Most non-randomized controlled trials (n=11; 73%) were rated with a moderate risk of bias according to the ROBINS-I tool. There were statistically significant differences between the pretreatment and posttreatment arches. The average expansion was significantly different from that predicted for each type of tooth in both the maxilla and mandible. Furthermore, the efficiency decreased from the anterior area to the posterior area in the upper arch.

CONCLUSION

Despite the fact that arch expansion with Invisalign® is not entirely predictable, clear aligner treatment is a viable option for addressing dentition crowding. The efficacy of expansion is greatest in the premolar area. More research focusing on treatment outcomes with different materials of aligners should be conducted in the future. Overcorrection should be considered when planning arch expansion with Invisalign. In the maxilla, the expansion rate decreases from the anterior to the posterior, and presetting sufficient buccal root torque of posterior teeth may result in improved efficiency of expansion.

Gingerol and Chitosan-Based Coating of Thermoformed Orthodontic Aligners: Characterization, Assessment of Anti-Microbial Activity, and Scratch Resistance: An In Vitro Study

Aim To prepare and characterize a 6-gingerol-incorporated chitosan biopolymer for coating on thermoformed aligners and evaluate its scratch resistance and antimicrobial activity. Material and methods In this in vitro study, 6-gingerol extract was prepared, incorporated with chitosan biopolymer into a coating solution and characterized using nuclear magnetic resonance imaging spectroscopy (NMR). Twenty thermoformed aligner samples were exposed to UV radiation for surface activation, then coated with a crosslinking agent. These were divided into four groups of five. The control group consisted of samples dip-coated in a chitosan solution for 15 minutes. The three test groups consisted of samples dip coated in a gingerol-chitosan coating solution, with each group representing the following time periods of dip coating: five, 10, and 15 minutes. The crosslinking of the coating with the aligner material was confirmed by a Fourier transform infrared spectroscopy (FTIR) test. A scratch test was carried out to evaluate the wear resistance of the coating, and the antibacterial properties of the coating were tested using a Disc Diffusion test. Results The NMR analysis confirmed the presence of 6-gingerol in the extract. The coating of 6-Gingerol on aligners was confirmed by FTIR spectroscopy. The wear resistance of aligners coated for 5 minutes, 10 minutes, and 15 minutes was 1.8 ± 0.09 N, 2.3 ± 0.021 N, and 3.06 ± 0.17 N, respectively, and the difference was statistically significant (p<0.05). The aligner coated for 15 minutes exhibited the widest zone of inhibition of up to 2.38 ± 0.44 mm against Streptococcus mutans, and the difference was statistically significant (p<0.05).​​​​​​ No antibacterial effect was found against E. Coli. Conclusion A novel coating material with 6-gingerol extract incorporated in chitosan biopolymer was prepared and characterized, followed by coating on thermoformed aligners. The coating showed antibacterial activity against Streptococcus mutans, and both the antimicrobial activity and wear resistance increased with coating duration.

The incidence and severity of open gingival embrasures in adults treated with clear aligners and fixed appliances: a retrospective cohort study

BACKGROUND

To evaluate the incidence and severity of open gingival embrasures (OGEs) in adult patients treated with clear aligners and fixed appliances.

METHODS

Two hundred non-extraction adult subjects with less than 5 mm of crowding (mean age, 24.6 ± 3.8 years) were enrolled in this retrospective study. The subjects were divided into the clear aligner (n = 100) and fixed appliance group (n = 100). The intraoral photographs were utilized to determine the incidence of OGEs in the upper arch between maxillary central incisors, as well as the lower arch between mandibular central incisors. Crown overlap, crown shape, posttreatment root angulation, the distance from the interproximal contact point (ICP) to the alveolar bone crest (ABC) after treatment and interproximal enamel reduction (IPR) were determined in the two groups.

RESULTS

The incidence of OGEs between maxillary and mandibular central incisors after orthodontic treatment was 35.0% and 38.0% in the clear aligner group, respectively, significantly higher than that (18.0% and 24.0%) in the fixed appliance group (P < 0.05). The average area of an OGE after clear aligner treatment was larger both in the maxilla (0.16 ± 0.12mm²) and mandible (0.21 ± 0.24mm²) compared with that (0.05 ± 0.03mm² and 0.05 ± 0.06mm²) after fixed appliance treatment (P < 0.05). No difference was found regarding pretreatment crown overlap, crown shape, treatment duration, posttreatment root angulation, amount and distribution of IPR and the distance from ICP to ABC.

CONCLUSIONS

The incidence and severity of OGEs were higher in adults treated with clear aligners. Clinicians should be aware of the risk of OGEs during treatment with clear aligners.

A retrospective study of the accuracy of Invisalign Progress Assessment with clear aligners

The objective of this study was to detective the accuracy of model superimposition and automatic analysis for upper and lower dentition width in Invisalign Progress Assessment during the process of clear aligners. 19 cases were included in this study. Pre-treatment dental cast (T0) and post-treatment dental cast after staged treatment (T1) were available for three-dimensional model superimposition. Subsequently, movements of maxillary teeth in the horizontal plane (cross-section) after staged treatment and width of upper and lower dentition were measured by three-dimensional model superimposition in the real world and Invisalign Progress Assessment separately. Consequently, the data collected from these two methods were compared. In Invisalign Progress Assessment, movements of maxillary teeth in the horizontal plane after staged treatment was 2.31 (1.59,3.22) [median (upper quartile, lower quartile)] millimeter (mm), while in three-dimensional model superimposition, the result was 1.79 (1.21,3.03) mm. The difference between the two groups is significant (P < 0.05). Intercanine width upper, intermolar width upper, intercanine width lower, and intermolar width lower were 36.55 ± 2.76 mm, 56.98 ± 2.62 mm, 28.16 ± 1.85 mm, 53.21 ± 2.72 mm separately in Invisalign Progress Assessment and were 36.48 ± 2.78 mm, 56.89 ± 2.58 mm, 28.05 ± 1.85 mm, 53.16 ± 2.64 mm separately in three-dimensional model analysis, which was no significant difference among these groups (P > 0.05). The data from Invisalign Progress Assessment was not in parallel with what was achieved from model superimposition with palate as a reference completely. The accuracy of model superimposition in Invisalign Progress Assessment needs further investigation, whereas the accuracy of model analysis in Invisalign Progress Assessment was accurate. Thereby, results from Invisalign Progress Assessment should be interpreted with caution by the orthodontist in the clinic.

Impact of Clear Aligners versus Fixed Appliances on Periodontal Status of Patients Undergoing Orthodontic Treatment: A Systematic Review of Systematic Reviews

The present umbrella review of four systematic reviews with meta-analysis aimed to assess whether clear aligners are associated with better periodontal conditions compared with fixed appliances in patients undergoing orthodontic treatment. The present study protocol was developed in accordance with the PRISMA statement before the literature search, data extraction, and analysis and was registered on PROSPERO (CRD42023401808). The question formulation, search, and study selection strategies were developed according to the PICO model. Systematic reviews with a meta-analysis published in English without date restriction were electronically searched across the Cochrane Library, Web of Science (Core Collection), Scopus, EMBASE, and MEDLINE/PubMed databases until 10 February 2023. An assessment of study quality was performed using the AMSTAR 2 tool. Differences in the PI, GI, and BOP in the short- and medium-term follow-ups, in the PPD in long-term follow-up, and the gingival recessions in the short-term follow-up were found between subjects with clear aligners and fixed appliances, revealing a slight tendency for clear aligners to be associated with healthier periodontal conditions. However, even if statistically significant, such differences would be negligible in a clinical environment. Therefore, the impact of orthodontic treatment with clear aligners and fixed appliances on periodontal health status should be considered comparable.

Role of six cytokines and bone metabolism biomarkers in gingival crevicular fluid in patients undergoing fixed orthodontic appliance treatment in comparison with aligners: a clinical study

OBJECTIVES

The objective of this study was to assess bone biomarkers and cytokines in patients with conventional labial appliances (CLAs) and aligners.

MATERIALS AND METHODS

Participants were recruited to undergo orthodontic treatment with CLAs and aligners according to predefined inclusion and exclusion criteria. Periodontal examination was accomplished at baseline and 4 weeks using the plaque index (PI), gingival index (GI), and bleeding on probing (BoP). Samples of gingival crevicular fluid (GCF) were collected at baseline (T0) before the start of treatment and at the 1-month follow-up (T1) to assess bone metabolic and inflammatory biomarkers. GCF from participants with CLAs and aligners was evaluated with enzyme-linked immunosorbent assay. Comparison between labial conventional orthodontic treatment and aligners were assessed using an unpaired t-test. The difference between T0 and T1 was measured using a paired t-test.

RESULTS

BoP, PI, and GI demonstrated no significant difference between participants treated with aligners and subjects with CLAs at baseline and at 4 weeks (P > .05). Bone markers and other biomarkers (tumor necrosis factor α, interleukin [IL]-α, IL-2, IL-6, and IL-8) showed significant differences (P < .05). Also, a significant difference between CLAs and aligners was noted among all biomarkers (P < .05) except IL-β.

CONCLUSIONS

Aligners and CLAs increase the level of inflammatory and bone metabolic biomarkers after 1 month.

Microbiome and metabolome associated with white spot lesions in patients treated with clear aligners

White spot lesions (WSLs) have long been a noteworthy complication during orthodontic treatment. Recently, an increasing number of orthodontists have found that adolescents undergoing orthodontic treatment with clear aligners are at a higher risk of developing WSLs. The oral microbiota and metabolites are considered the etiologic and regulatory factors of WSLs, but the specific impact of clear aligners on the oral microbiota and metabolites is unknown. This study investigated the differences in the salivary microbiome and metabolome between adolescents with and without WSLs treated with clear aligners. Fifty-five adolescents (aged 11-18) with Invisalign appliances, 27 with and 28 without WSLs, were included. Saliva samples were analyzed using 16S rRNA gene sequencing and ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS); the data were further integrated for Spearman correlation analysis. The relative abundances of 14 taxa, including Actinobacteria, Actinomycetales, Rothia, Micrococcaceae, Subdoligranulum, Capnocytophaga, Azospira, Olsenella, Lachnoanaerobaculum, and Abiotrophia, were significantly higher in the WSL group than in the control group. Metabolomic analysis identified 27 potential biomarkers, and most were amino acids, including proline and glycine. The metabolites were implicated in 6 metabolic pathways, including alanine, aspartate and glutamate metabolism; glycine, serine and threonine metabolism; and aminoacyl-tRNA biosynthesis. There was a correlation between the salivary microbial and metabolomic datasets, reflecting the impact of clear aligners on the metabolic activity of the oral flora. A concordant increase in the levels of Lachnoanaerobaculum, Rothia, Subdoligranulum and some amino acids had predictive value for WSL development. In summary, when adolescents undergo long-term clear aligner therapy with poor oral hygiene habits, clear aligners can disrupt the balance of the oral microecosystem and lead to oral microbiota dysbiosis, thereby increasing the risk of developing WSLs. Our findings might contribute to the understanding of the pathogenesis of WSLs and provide candidate biomarkers for the diagnosis and treatment of WSLs associated with clear aligners.

Effectiveness of clear aligners in achieving proclination and intrusion of incisors among Class II division 2 patients: a multivariate analysis

BACKGROUND

The predictability of incisor movement achieved by clear aligners among Class II division 2 patients is poorly understood. The aim of this retrospective study was to determine the effectiveness of clear aligners in proclining and intruding upper incisors and its influencing factors.

METHODS

Eligible patients with Class II division 2 malocclusion were included. For clear aligner therapy, three types of incisor movements were designed: proclination, intrusion and labial movement. Pre-treatment and post-treatment dental models were superimposed. The differences between predicted and actual (DPA) tooth movement of incisors were analyzed. Univariate and multivariate linear regression were used to analyze the potential influencing factors.

RESULTS

A total of 51 patients and their 173 upper incisors were included. Actual incisor proclination and intrusion were less than predicted ones (both P < 0.001), while actual labial movement was greater than predicted one (P < 0.001). Predictability of incisor proclination and intrusion was 69.8% and 53.3%, respectively. Multivariate linear regression revealed that DPA of proclination was significantly positively associated with predicted proclination (B = 0.174, P < 0.001), ipsilateral premolar extraction (B = 2.773, P < 0.001) and ipsilateral canine proclination (B = 1.811, P < 0.05), while negatively associated with molar distalization (B = - 2.085, P < 0.05). The DPA of intrusion was significantly positively correlated with predicted intrusion (B = 0.556, P < 0.001) while negatively associated with labial mini-implants (B = - 1.466, P < 0.001). The DPA of labial movement was significantly positively associated with predicted labial movement (B = 0.481, P < 0.001), while negatively correlated with molar distalization (B = - 1.004, P < 0.001), labial mini-implants (B = - 0.738, P < 0.001) and age (B = - 0.486, P < 0.05).

CONCLUSIONS

For Class II division 2 patients, predicted incisor proclination (69.8%) and intrusion (53.3%) are partially achieved with clear aligner therapy. Excessive labial movement (0.7 mm) of incisors may be achieved. Incisor movement is influenced by predicted movement amount, premolar extraction, canine proclination, molar distalization, mini-implants and age.

[Comparison of the outcome of orthodontic dental movement using aligners versus fixed orthodontics: a review]

Introduction

The aligners have become a preferred alternative in terms of orthodontic treatment, surpassing the choice of conventional brackets, due to the comfort and aesthetics that the aligners represent, however, the final result with this system continues to be a controversial issue. The objective of this review was to verify the effectiveness of the treatment completed with aligners versus conventional brackets.

Materials and methods

An exhaustive search was carried out in the PubMed, ScienceDirect, Scopus and Embase databases up to the date of January 5, 2023, including comparative studies that evaluated the final result and treatment time of the aligners compared to conventional braces. Two researchers carefully selected the articles evaluated and analyzed different key topics on the subject.

Results

In this study, 8 articles were included, according to the studies, the vast majority did not find significant differences in completion between the compared groups. In addition to this, the treatment time in 3 articles was faster with aligners, in 3 articles it was faster with conventional brackets, and in one article no significant difference was found, so it is not yet established whether a system is faster than the other.

Conclusions

Both aligners and conventional fixed orthodontics had good results at the end of orthodontic treatment and presented a similar treatment time, however, the majority of treated cases belonged to malocclusions of medium to low complexity, so these cannot be generalized. findings to all malocclusions.

Clear aligner therapy in the mixed dentition: Indications and practitioner perspectives

INTRODUCTION

This study evaluated current trends and perspectives among orthodontists regarding clear aligner therapy in the mixed dentition (CAMD), including insights into perceived indications, compliance, oral hygiene, and other factors.

METHODS

An original, 22-item survey was mailed to a randomized, nationally representative sample of practicing orthodontists (n = 800) and a specific, randomized subsample of high-aligner-prescribing orthodontists (n = 200). Questions assessed respondents' demographic information, experience with clear aligner therapy, and perceived advantages and disadvantages of CAMD compared with fixed appliances (FAs). Responses were compared using McNemar's chi-square and paired t tests to assess CAMD vs FAs.

RESULTS

One thousand orthodontists were surveyed, and 181 (18.1%) responded over 12 weeks. CAMD use was less common than mixed dentition FAs, but most respondents predicted an increase in their future CAMD use (57.9%). Among respondents using CAMD, the number of patients with mixed dentition treated with clear aligners was significantly lower than the number of total patients with clear aligners (23.7% vs 43.8%; P <0.0001). Fewer respondents considered skeletal expansion, growth modification, sagittal correction, and habit cessation feasible indications for CAMD compared with FAs (P <0.0001). Perceived compliance was similar for CAMD and FAs (P = 0.5841), but perceived oral hygiene was significantly better with CAMD (P <0.0001).

CONCLUSIONS

CAMD is an increasingly common treatment modality for children. Most surveyed orthodontists reported limited indications for CAMD compared with FAs but perceived noticeable benefits for oral hygiene with CAMD.

Combined use of F22 aligners and intermaxillary elastics in mild skeletal Class II: Two case reports

INTRODUCTION

The aim of these two case-reports is to illustrate and compare the therapeutic effects of Class II elastics in combination with F22 aligners in an adult and an adolescent patient, respectively.

CASE PRESENTATION

Two patients with a mild skeletal Class II malocclusion, associated with mild-to-moderate crowding, presented for orthodontic treatment. The first patient was 12 years old, while the second was 40 years old. In both cases, the goal was to obtain bilateral molar and canine Class I with ideal overjet and overbite, and Class II skeletal relationship improvement in the young patient as well. Both treatments were approached without extractions and using clear aligners (CAs) in combination with Class II elastics, giving the patient the opportunity to take advantage of a therapy that is both comfortable and aesthetic.

DISCUSSION

Final records of both cases demonstrate how appropriate analysis and diagnosis enable CAs in conjunction with Class II elastics to be used with considerable efficiency and efficacy for Class II treatment. In the first case, the key to success was exploiting residual jaw growth, while in the second case it was careful orthodontic digital planning.

CONCLUSION

In the presence of good patient compliance, CAs associated with Class II elastics provide satisfactory occlusal outcomes if biomechanics and digital set-up are carefully evaluated and executed and if diagnosis is appropriate.

IPR treatment and attachments design in clear aligner therapy and risk of open gingival embrasures in adults

BACKGROUND

The incidence of open gingival embrasures (OGE) in patients after fixed appliance treatment is relatively high, while there are no detailed reports on patients after clear aligner therapy. Also, no clinical studies with large sample size have investigated whether interproximal enamel reduction (IPR) can actually avoid OGE. The purpose of this study was to determine the prevalence of OGE in adults after clear aligner therapy and to investigate the risk of OGE associated with IPR treatment and attachment design, focusing on the amount and distribution in mandibular anterior teeth.

METHODS

Pre-treatment and post-treatment intraoral frontal photographs of 225 non-extraction patients were evaluated retrospectively for the occurrence and severity of OGE. The amount of IPR and the number of attachments in the anterior teeth from subjects after screening were recorded according to the first version of clear aligner software (Clincheck, San Jose, USA) and clinical medical documents. Logistic regression analysis was performed to identify the factors contributing to OGE.

RESULTS

The incidence of OGE in non-extraction patients after clear therapy between maxillary and mandibular central incisors was 25.7% and 40.3%, respectively. IPR was not associated with the occurrence of OGE but was associated with severity (P < 0.05). The number of attachments in the anterior teeth or central incisors was significantly related to the incidence of OGE (P < 0.05) but was not associated with severity.

CONCLUSION

A high rate of OGE occurs after clear aligner therapy. Clinicians should be aware of the application of IPR and the design of attachments during clear aligner therapy.

Isolation of Clinical Microbial Isolates during Orthodontic Aligner Therapy and Their Ability to Form Biofilm

The purpose of this study is to calculate microbiological composition of aligners after a day of wearing them. To date, the dental market for orthodontists offers many ways to correct bites. Aligners are transparent and almost invisible from the teeth. They are used for everyday wear to correct the incorrect position of the teeth, which was once considered the prerogative of braces. Scientists worldwide have repeatedly considered questions regarding the interaction between aligners and the oral cavity's microflora; however, the emphasis has mainly shifted toward species composition and antibiotic resistance. The various properties of these microorganisms, including biofilm formation, adhesion to various cells, and the ability to phagocytize, have not been studied so widely. In addition, these characteristics, as well as the microorganisms themselves, have properties that change over time, location, and in certain conditions. In this regard, the problem of biofilm formation in dental practice is always relevant. It requires constant monitoring since high contamination of orthodontic materials can reduce the effectiveness of local anti-inflammatory therapy and cause relapses in caries and inflammatory diseases of the oral cavity. Adhesive properties, one of the key factors in forming the architectonics of biofilms, provide the virulence factors of microorganisms and are characterized by an increase in optical density, determining the duration and retrospectivity of diagnostic studies. This paper focuses on the isolation of clinical microbial isolates during aligner therapy and their ability to form biofilms. In the future, we plan to use the obtained strains of microorganisms to create an effective and safe biofilm-destroying agent. We aimed to study morphometric and densitometric indicators of biofilms of microorganisms persisting on aligners.

Presurgical orthodontic decompensation with clear aligners

INTRODUCTION

Orthodontists, surgeons, and patients have taken an interest in using clear aligners in combination with orthognathic surgery. This study aimed to evaluate the accuracy of tooth movements with clear aligners during presurgical orthodontics using novel 3-dimensional superimposition techniques.

METHODS

The study sample consisted of 20 patients who have completed presurgical orthodontics using Invisalign clear aligners. Initial (pretreatment) digital dental models, presurgical digital dental models, and ClinCheck prediction models were obtained. Presurgical models were superimposed onto initial ones using stable anatomic landmarks; ClinCheck models were superimposed onto presurgical models using surface best-fit superimposition. Five hundred forty-five teeth were measured for 3 angular movements (buccolingual torque, mesiodistal tip, and rotation) and 4 linear movements (buccolingual, mesiodistal, vertical, and total scalar displacement). The predicted tooth movement was compared with the achieved amount for each movement and tooth, using both percentage accuracy and numerical difference.

RESULTS

Average percentage accuracy (63.4% ± 11.5%) was higher than in previously reported literature. The most accurate tooth movements were buccal torque and mesial displacement compared with lingual torque and distal displacement, particularly for mandibular posterior teeth. Clinically significant inaccuracies were found for the buccal displacement of maxillary second molars, lingual displacement of all molars, intrusion of mandibular second molars, the distal tip of molars, second premolars, and mandibular first premolars, buccal torque of maxillary central and lateral incisors, and lingual torque of premolars and molars.

CONCLUSIONS

Superimposition techniques used in this study lay the groundwork for future studies to analyze advanced clear aligner patients. Invisalign is a treatment modality that can be considered for presurgical orthodontics-tooth movements involved in arch leveling and decompensation are highly accurate when comparing the simulated and the clinically achieved movements.

Gingival Margins' Modifications during Orthodontic Treatment with Invisalign First®: A Preliminary Study

The aim of the study was to assess modifications of gingival morphology at the end of Phase I treatment with Invisalign First. Eighteen subjects (ten females, eight males, mean age nine years) treated with Invisalign First were selected. The following parameters were measured on intraoral photographs before treatment (T0) and after the first set of aligners (T1) at level of permanent incisors, deciduous canines and molars: gingival margin height (GMH) and deciduous canine inclination (DCI). A paired t-test was used to evaluate T1-T0 changes. The level of significance was established at 5%. Deciduous canines' GMH showed a major reduction between T1 and T0 accounting for 0.87 mm and 0.86 mm, respectively on the right and left sides. DCI increased for all patients in the interval T0-T1 on both sides, +7.11° on the right and +7.5° on the left. Tooth movement during Invisalign First induced significant modifications of gingival contour resulting in a more harmonious smile.

Predicting patient experience of Invisalign treatment: An analysis using artificial neural network

Objective

Poor experience with Invisalign treatment affects patient compliance and, thus, treatment outcome. Knowing the potential discomfort level in advance can help orthodontists better prepare the patient to overcome the difficult stage. This study aimed to construct artificial neural networks (ANNs) to predict patient experience in the early stages of Invisalign treatment.

Methods

In total, 196 patients were enrolled. Data collection included questionnaires on pain, anxiety, and quality of life (QoL). A four-layer fully connected multilayer perception with three backpropagations was constructed to predict patient experience of the treatment. The input data comprised 17 clinical features. The partial derivative method was used to calculate the relative contributions of each input in the ANNs.

Results

The predictive success rates for pain, anxiety, and QoL were 87.7%, 93.4%, and 92.4%, respectively. ANNs for predicting pain, anxiety, and QoL yielded areas under the curve of 0.963, 0.992, and 0.982, respectively. The number of teeth with lingual attachments was the most important factor affecting the outcome of negative experience, followed by the number of lingual buttons and upper incisors with attachments.

Conclusions

The constructed ANNs in this preliminary study show good accuracy in predicting patient experience (i.e., pain, anxiety, and QoL) of Invisalign treatment. Artificial intelligence system developed for predicting patient comfort has potential for clinical application to enhance patient compliance.

Visualization of orthodontic forces generated by aligner-type appliances

Recently, the number of patients who request esthetically pleasing aligner-type orthodontic appliances (referred to as aligners) has been increasing. However, the orthodontic forces generated by these aligners are still unknown. This study aimed to verify whether the orthodontic force in aligners can be estimated by measuring near infrared 2D birefringence, and to visualize the orthodontic force. We measured the mechanical and photoelastic properties of transparent orthodontic thermoplastic specimens to correlate the optical retardation with the applied load. The results confirmed equivalence between the mechanical properties and the photoelasticity. In addition, the 2D retardation distribution that occurred when stress was applied to the sample was mapped and visualized. This indicates that it is possible to estimate and visualize the orthodontic force using the retardation obtained by near infrared 2D birefringence measurement.

Health promotion through structured oral hygiene and good tooth alignment

Aim

Periodontal diseases and caries are two of the most common forms of chronic degenerative diseases, with consequences not only for the oral cavity manifesting as tooth loss, orofacial pain and xerostomia, but also with effects on the cardiovascular system and, in the elderly, on the pneumonia rate. This can be prevented or controlled by structured oral hygiene.

Method

Based on a systematic literature search in PubMed, the possibilities for ensuring structured oral hygiene are analyzed.

Results and conclusion

Limiting the consumption of sugary meals and beverages, regular removal of food debris - supplemented by sugar-free chewing gum if desired - and preventing plaque formation by brushing with fluoridated toothpastes, using dental floss and interdental brushes after meals, serve to prevent or control gingivitis, periodontitis and caries. In the long term, the development of periodontitis-associated cardiovascular diseases and, in the elderly, the risk of pneumonia can probably be reduced. Antiseptic rinsing of the oral cavity is an important supplement to prevent periodontitis, especially in cases of limited ability to perform mechanical biofilm removal, but also for the prevention of respiratory infections. Proper functional tooth alignment is important for optimal mechanical cleaning to prevent plaque accumulation. If correction of misaligned teeth is possible with the use of removable aligners instead of fixed orthodontic appliances, these are to be preferred because of the better accessibility for mechanical hygiene measures.

Clinical Use of Aligners Associated with Nuvola® OP System for Transverse Maxillary Deficiency: A Retrospective Study on 100 Patients

Introduction: Aligners represent a common treatment for orthodontic patients thanks to their countless advantages including aesthetics, comfort, and oral hygiene maintenance; at the same time, they are associated with a reduced number of visits and a low incidence of complications. Although aligners have undergone considerable improvements over time, to date they have limitations in resolving the most serious malocclusions related to transverse maxillary deficiency. The aim of the present study was to retrospectively evaluate an orthodontic protocol (the Nuvola® OP System) which associates a morpho-functional corrector (to be used for 30 min/day) with the aligner, allowing for the treatment of cases that would be difficult or unpredictable with aligners alone. Methods: Linear measurements were taken on STL files of 100 patients. In 77 patients between 18 and 55 years (mean 28.6 ± 16.2 (standard deviation) years), 3D superimpositions of the maxilla obtained from intraoral scans before and after treatment were performed in order to evaluate the degree of maxillary expansion. The normality of the data distribution was tested. The pre- and post-treatment data were compared using a paired t-test with a 5% significance level. After treatment, a questionnaire was proposed to assess patients’ degree of satisfaction and compliance. Results: A statistically significant difference (p < 0.05) for each distance evaluated was found. The maximum expansion was obtained at the first molar level (2.35 ± 1.64 mm). Of the subjects who completed the questionnaire, 96% were satisfied and 90% were able to perform the protocol without difficulty for the required duration. Conclusions: A significant expansion of the maxillary arch as well as a high degree of patient satisfaction and compliance were observed with the Nuvola® OP System. Further studies are needed in order to clinically evaluate the relative contribution of the aligners and morpho-functional device to the obtained expansion.

Three-dimensional analysis of aligner gaps and thickness distributions, using hard x-ray tomography with micrometer resolution

PURPOSE

The morphology of a polymer aligner, designed according to an orthodontic treatment plan, determines clinical outcomes. A fundamental element of orthodontic tooth movement with aligner treatment is the fit of the aligner's surface to the individual teeth. Gaps between the aligner and teeth do occur because current aligner fabrication is not capable of completely reproducing the complex anatomy of the individual denture. Our study aims at a quantitative three-dimensional assessment of the fit between optically transparent aligners placed on a polymeric model of the upper dental arch for two thermofoil thicknesses at preselected thermoforming temperatures.

APPROACH

Using an intraoral scan of a subject's upper dental arch, eight models were printed using a stereolithographic system. A series of eight NaturAligners® was manufactured with a pressure molding process, using thermofoils with thicknesses of 550 and 750    μ m and preselected process temperatures between 110°C and 210°C. These aligners placed on the corresponding models were imaged by an advanced micro computed tomography system. The aligners and the models were segmented to extract the gaps and aligners' local thicknesses as a function of the processing temperature for the two foil thicknesses.

RESULTS

The results indicate that the aligners show a better fit when the foils are processed at higher temperatures. Nevertheless, processing temperatures can be kept below 150°C, as the gain becomes negligible. Thermal processing reduces the average thickness of the aligners to 60% with respect to the planar starting foil. These thickness distributions demonstrate that the aligners are generally thicker on the occlusal surfaces of molars and premolars but thinner around the incisors and buccal as well as on oral surfaces.

CONCLUSIONS

Hard x-ray tomography with micrometer resolution is a powerful technique employed to localize the gaps between aligners and teeth, and it also enables film thickness measurements after thermoforming. The thicker film on the occlusal surfaces is most welcome because of aligner abrasion during wear. The NaturAligner® surfaces consist of a 25 - μ m -thin cellulose layer, and thus the microplastics released via abrasion of less than this thickness are expected to be substantially less critical than for other commercially available, optically transparent aligners.

Differences in finished case quality between Invisalign and traditional fixed appliances

OBJECTIVES

To compare the treatment and posttreatment effects of Invisalign aligners that incorporated SmartForce features and attachments to traditional fixed appliances.

MATERIALS AND METHODS

This randomized controlled trial included 66 patients, 32 aligners, and 34 fixed-appliance patients. The median ages of the aligner and braces patients were 26.7 (interquartile range [IQR]: 9.8) and 25.9 (IQR: 16.6) years, respectively. Pretreatment occlusion was assessed using the ABO Discrepancy Index. Posttreatment (T1) and 6-month retention (T2) occlusions were quantified using the ABO Objective Grading System (OGS) scores.

RESULTS

The braces group finished treatment significantly (P < .001) earlier (0.4 years) than the aligner group. The median DI scores for the aligner and braces groups were 4.5 and 7.0, respectively, which was a statistically significant (P = .015), but clinically insignificant, difference. There were no statistically significant between-group differences for the total OGS scores or any of the individual component scores at debond (T1) or after 6 months of retention (T2). During the posttreatment period, alignment and overjet worsened significantly in the aligner group, while buccolingual inclinations and occlusal relations improved. Over the same period, alignment worsened in the braces group and buccolingual inclinations improved. There was no statistically significant between-group difference in posttreatment changes of the total OGS scores.

CONCLUSIONS

While patients with simple malocclusions require 4.8 months longer treatment times with aligners than traditional braces, the treatment and 6-month posttreatment occlusal outcomes are similar.

Clear Aligner Treatments in Orthoperio Patients

Introduction. Orthodontic treatment is a recognized approach to support specific periodontal issues thanks to its capability to manipulate periodontal tissues. This concept is certainly not new, but the use of aligners in certain clinical conditions can be considered as being innovative when a multidisciplinary treatment is necessary. Moreover, aligners enable to plan 3D tooth movements, root placement, staging, and range of dental movements, alongside the improvement of oral hygiene. Thus, aligners can be suitable for the treatment of periodontal issues. In this article, the authors present two clinical cases with different periodontal issues: one with superficial periodontal problems and the other with a deep one. Both cases were successfully treated with aligners, highlighting how this invisible and comfortable tool can simplify the management of complex adult treatments. Conclusion. Digital workflow is the key for success in the aligner technique. The possibility to design a virtual plan of treatment and to transfer it in the real clinical world represents a way to limit errors and to reduce the time of orthodontic therapy.