Advances in clear aligner therapy: comparative evaluation of the optical properties and bacterial adhesion of 3D direct-printed and thermoformed aligners

In vitro assessment of dental erosion caused by clear aligners

Introduction Adhesion of bacteria, especially Streptococcus mutans (S. mutans), to the surface of tooth restorations is a factor in the etiology of secondary caries. Given the ever-increasing popularity of bleaching procedures, the aim of the present study was to evaluate adhesion of S. mutans and surface roughness (SR) of microhybrid composite resin and giomer subsequent to the application of 15% carbamide peroxide. Materials and methods Twenty disk-shaped samples were prepared from each material, measuring 8 mm in diameter and 2 mm in thickness. Then, the samples of each material were divided into two groups (n = 10): (a) microhybrid without bleaching; (b) microhybrid with bleaching; and (c) giomer without bleaching; and (d) giomer with bleaching. The samples in groups I and III were immersed in artificial saliva for 14 days without any bleaching procedure; the samples in groups II and IV underwent a bleaching procedure on their polished surfaces with 15% carbamide peroxide for 14 days (4 hours of bleaching and 20 hours of immersion in artificial saliva). The SR of all the samples was determined with the use of a profilometer. The samples were added to the culture medium after 4 hours of placement in a microbial suspension at 37°C; after 24 hours of incubation at 37°C, the bacterial counts, indicating the number of bacteria adhering to the surface, were determined by counting them in the plates containing the solid culture medium. Results The type of the restorative material had a significant effect on SR, with greater SR in giomer (p = 0.03). However, bleaching had no significant effect on SR (p = 0.099). In relation to the rate of bacterial adhesion (BA), both the types of the restorative materials and bleaching procedures were significantly effective; in this context, there was more BA in microhybrid composite resin samples that did not undergo bleaching (p < 0.001). Bleaching resulted in the adhesion of S. mutans to the surface of both materials decrease. Pearson's correlation coefficient did not reveal any correlation between BA and SR (p = 0.42). Conclusion The BA was higher in microhybrid composite resin, and SR was higher in giomer. The BA was higher in samples that did not undergo a bleaching procedure. Clinical significance There is no change in the SR of microhybrid composite resin and giomer after application of 15% carbamide peroxide; therefore, it is not necessary to polish or replace these restorative materials after bleaching. In addition, use of 15% carbamide peroxide does not increase caries risk. How to cite this article Mohammadi N, Mowlaie S, Savadi- Oskoee S, Ebrahimi ME, Rikhtegaran S, Rahbar M, Pirzadeh T. Effect of 15% Carbamide Peroxide on the Surface Roughness and Adhesion of Streptococcus mutans to Microhybrid Composite Resin and Giomer. World J Dent 2017;8(4):288-295.

Lateral cephalograms have the inherent drawback of superimposition of bilateral structures, while landmarks are more reproducible on CBCT scans. Yet no studies in the literature have utilized 3D imaging to investigate the effects of clear aligners on anterior open bite. Therefore, The aim is to measure the skeletal and dental changes that contribute to anterior open bite closure with clear aligner therapy on CBCT scans. It is a single-arm retrospective study that included 40 cases of anterior open bite who were treated using Invisalign. Pre- and post-treatment CBCT scans were traced to record 13 dental and 3 skeletal measurements. A paired t-test was conducted to compare the mean values of pre- and post-treatment measurements. Combined intrusion of the maxillary right and left molars was statistically significant, meanwhile mandibular molars maintained their vertical position. Maxillary incisors were extruded and retroclined significantly, whereas mandibular incisors were only extruded. While anterior facial height was decreased insignificantly, both lower anterior facial height and mandibular plane angle showed a significant decrease. Clear aligner (Invisalign) therapy is effective in the management of anterior open bite through vertical control, maxillary molars intrusion, maxillary incisors extrusion, maxillary and mandibular incisors retroclination, and mandibular autorotation.

Objectives: Over the last two decades, clear aligners have become a mainstay in contemporary orthodontic practice primarily due to improvements in digital and 3D printing technologies, a growing interest in esthetic orthodontics, especially in the adult population, and aggressive manufacturer marketing internationally. Material and Methods: PubMed, Google Scholar, Cochrane Library, and EMBASE databases were searched from January 1998 to November 2021. The search terms used were “Invisalign” OR “clear aligner.” A total of 7000 records were searched, of which 369 potentially relevant articles were retrieved in full. 190 studies met the selection criteria following screening and were included in the scoping review. Results: This review scopes and analyses published orthodontic literature about CA according to a year-wise distribution into 3 groups, 2001–2010/2011–2020/2021. Most of the studies were published in the period between 2011 and 2020, with 138 studies accounting for 73%. The year 2021 followed, with 31 studies accounting for 16%, which was greater than the number of studies published in 10 years from 2001 to 2010. Studies were also classified based on the study designs with most of the published studies representing the lowest level of evidence including case reports, case series, narrative reviews, expert opinions, and editorials accounting for 137 studies, whereas case-control studies were the least reported studies with only 4 studies reported in the literature. In addition, they were categorized into seven main domains: (1) Biological considerations associated with clear aligner therapy (CAT), (2) Treatment outcomes considerations associated with CAT, (3) Geometrical considerations associated with CAT (clinical), (4) Biomechanical considerations associated with CAT (Laboratory/Finite element analysis), (5) Biomaterial considerations associated with CAT, (6) Patient education and experience and aesthetic and social perception of CAT, and (7) Miscellaneous. Treatment outcome considerations associated with CAT had the greatest percentage representing 36% of the total published domains, while the final place was occupied by the biomechanical considerations associated with CAT accounting for only 4% of the published domains about CAT. Conclusion: Treatment outcome was the domain most commonly reported by studies accounting for (36%). Most of the published studies are at the lowest level of evidence including case reports, case series, narrative reviews, and expert opinions. The vast majority of studies utilized only a single clear aligner brand. There is a greater need for research that studies CAT from a holistic perspective.

Objective To explore the frictional properties of stainless steel used in orthodontic treatment with surface modification of different alloy thin films. Methods CN Stainless steel which are used to made orthodontic wire are shaped to pieces with a diameter of 20mm and a 1mm thickness. Carbon nitride(CN) and Titanium nitride (TiN) film were deposited on these pieces by ion beam and Titanium dioxide (TiO2) film was deposited by sol-gel method. Frictional coefficients were measured by Universal Micro-Tribotester. Surface roughness(Sa) was measured by 3D white-light interfering profilometer. Each material was immersed in artificial saliva with Fluoride concentration of 0%, 0.05% and 0.1% for 3 days, and was measured for Frictional coefficient and Sa. The results were calculated and compared by t-test. Results The friction coefficient of as-received stainless-steel samples is: stainless steel 0.431±0.109, and the surface roughness (Sa) is 0.175±0.008 μm. The friction coefficient declined significantly after deposition of CN film and increased slightly after deposition of TiN film, but the roughness after both processes remained stable. The differences of frictional coefficient between the coatings and original stainless steel pieces were significant (P<0.001). The differences of frictional coefficient between the coatings and substrate were significant (P<0.001). After immersion in different concentrations of artificial fluoride saliva, the friction coefficient of TiN film increased. After 3-day immersion in artificial non-fluoride saliva, no significance was found in Sa in all three materials. TiO2, with weak adhesive strength and porous surface, was not applicable for friction coefficient test. Conclusions CN thin film would decrease the friction coefficient of stainless steel wire and could maintain a relative stable friction coefficient after immersion in fluoride saliva, and it can be a potential material used in future improvement of archwire propertie. Key words: Orthodontic; Stainless steel; Arch-wire; Surface modification; Friction coefficient

Clear aligner therapy has an aesthetic advantage over fixed appliance therapy. However, to our knowledge, no study has objectively compared patient orthodontic and aesthetic outcomes between clear aligner and fixed appliance therapies administered after orthognathic surgery (OGS). This study included patients with no history of congenital craniofacial deformities who underwent surgery-first OGS and received clear aligner or fixed appliance therapy. The patients' grades on the Dental Health Component (DHC) and Aesthetic Component of the Index of Orthodontic Treatment Need and scores on the Peer Assessment Rating (PAR) index were calculated before OGS (T0), after OGS (T1), and after orthodontic therapy (T2). This study included 33 patients (clear aligner therapy, n = 19; fixed appliance therapy, n = 14). No considerable between-group differences were noted in the DHC and AC grades at T0, T1, or T2. Furthermore, percentage of reduction in the PAR index score was more significant in the clear aligner group (74.4%) than in the fixed appliance group (63.2%) from T0 to T1 ( P = 0.035); however, no between-group differences were noted from T1 to T2 or from T0 to T2. Both groups exhibited substantially improved DHC grades, Aesthetic Component grades, and PAR index scores at T1 and T2. Patient outcomes were similar between the clear aligner and fixed appliance groups after orthodontic therapy. However, the former group exhibited more favorable immediate results after OGS than did the latter group. Thus, as an adjunct therapy for patients with malocclusion, clear aligner therapy may be more effective than fixed appliance therapy. Therapeutic, II.

In recent years, clear aligners have become a well-liked substitute for traditional braces in orthodontic treatment. Examining the effects of clear aligners on periodontal health and plaque accumulation is the goal of this review. To examine pertinent studies that have been published up to this point, a comprehensive evaluation of the literature was carried out. The review includes research on the microbial alterations in tooth plaque composition that occur during clear aligner therapy and the subsequent impact on periodontal tissues. Clear aligners and traditional braces are also compared with respect to how they affect gingival health, periodontal disease prevalence, and oral hygiene practices.In terms of plaque control, the results imply that transparent aligners offer special benefits and challenges. An important factor influencing the microbiological environment in the oral cavity is patient compliance, the type of aligner used, and the subtleties of its design. Moreover, the effect of orthodontic therapies on periodontal health is explored, providing insight into possible associations between the use of clear aligners and periodontal results. By underlining the necessity of individualized oral hygiene management strategies during clear aligner therapy, this review offers orthodontic practitioners’ insightful information. It highlights the need of maintaining periodontal health throughout orthodontic treatment and stresses the necessity of a multidisciplinary approach to optimize patient outcomes. In summary, this comprehensive review provides an overview of the most recent findings regarding the impact of clear aligners on plaque and periodontal health. By teaching clinicians, researchers, and patients about the subtleties of oral hygiene care during orthodontic treatment, the findings are meant to direct the development of effective strategies for maintaining good periodontal health in patients getting clear aligner therapy.

This study explored the layperson's perception of comfort, satisfaction, and willingness to use various accessories in clear aligner therapy. A total of 267 people analyzed standardized intraoral photographs of a female model in orthodontic treatment using: 1) only clear aligner (CA), the control group; 2) clear aligner+attachments (AT); 3) clear aligners+Cl II elastics (EL); 4) clear aligner+hybrid treatment with esthetic braces (HEB); 5) Clear aligner+hybrid treatment with metallic braces (HMB); 6) clear aligner+mini-implants (MI); 7) clear aligner+mini-implants and elastics for intrusion (MIE). In addition, a social media questionnaire was distributed to assess the willingness to undergo orthodontic treatment with various accessories. There was a significant difference between CA and all the other groups (P<0.001), with CA being considered more comfortable and providing greater satisfaction compared to other accessories. Moreover, AT showed a significant difference in reducing treatment time compared to other groups. The CA was the most comfortable, exhibiting a higher satisfaction rate and a greater willingness to use it. The AT therapy was perceived as more comfortable and was associated with higher satisfaction and a greater likelihood of use, especially if it resulted in reduced treatment time. On the other hand, the participants reported that the HMB, MI, and MIE accessories were less comfortable.

ABSTRACTObjectivesThe primary aim of the investigation was to survey clear aligner therapy (CAT) use among general dentists in Australia. A secondary aim was to evaluate the factors that influenced general dentists in Australia not to provide CAT.Material and MethodsGeneral dentists registered with the Australian Health Practitioner Regulation Agency were invited to participate in a structured cross‐sectional electronic survey. The survey covered demographics, preferred CAT systems and practices, relevant treatment planning and retention protocols, patient‐reported CAT issues, pertinent respondent opinions, and reasons for not providing CAT. Descriptive statistics were computed via GraphPad Prism v10 (GraphPad Software Inc., La Jolla, CA, USA).ResultsMost of the 264 (n = 172; 65.2%) respondents indicated that they provided CAT. The majority (n = 82; 58.6%) reported that they treated between 1 and 20 patients with CAT annually. Invisalign was the most used system (n = 83; 61.2%), with 55 (41.7%), indicating that they used more than one system. Most (n = 124; 98.4%) were comfortable using CAT for mild crowding, whereas 73.4% (n = 94) were not comfortable in treating severe crowding with CAT. The median (IQR) number of patients per respondent treated with extraction of a permanent incisor or premolar was 0 (0). Issues regarding tooth positions were reportedly always or mostly in need of change in the initial treatment plan by 68.7%. Problems regarding patient compliance with CAT wear protocols (n = 67; 45.6%) and the predictability of treatment outcomes (n = 31; 21.1%) were the most identified themes of the free‐text comments. Over 80% of those who did not provide CAT indicated that they preferred to refer to an orthodontist for management.ConclusionAlmost two‐thirds of the respondents provided CAT. Invisalign was the most used system. The majority use CAT combined with nonextraction treatment. Most of those who did not provide CAT preferred to refer to an orthodontist for patient management.

Antimicrobial activity, bacterial adhesion, and surface morphology of TiO2 nanoparticle-coated orthodontic elastomeric ligatures: An in vitro study.

Discoloration of provisional restorations can result in esthetic problems which are critically important in, for example, anterior areas and may compromise the acceptability of the restoration. The purpose of this study was to investigate the effect of tea on provisional restorative materials. This study was designed to measure the degree of color change of three acrylic resin provisional materials, before and after immersion in artificial saliva and artificial saliva-tea solution for 2 and 4 weeks. Three types of acrylic provisional materials (duralay, tempron, acropars TRP), were studied. Twenty disks (20 ± 0.1 mm by 2 ± 0.05 mm) were fabricated from each material. Specimens were polished with acrylic bur using pumice and diamond polishing paste. Base line color was measured using a spectrophotometer. Ten disks were stored in artificial saliva and 10 were stored in a solution of artificial saliva and tea at room temperature. Color measurements were made after 2 and 4 weeks of immersion. Differences in color changes were compared by two way ANOVA, across the six groups, followed by a Turkey-Kramer's multiple comparison test. For specimens immersed in artificial saliva, the color change of methyl methacrylate materials; duralay (ΔE=4.94) and tempron (ΔE=6.54), was significantly more than butyl methacrylate material; acropars (ΔE=4.10). After immersion in an artificial saliva- tea solution, tempron exhibited less color change (ΔE=8.50) compared to duralay (ΔE=10.93) and acropars (ΔE=15.64). Color stability of methyl methacrylate is higher than butyl methacrylates so if provisional materials are used for extended periods of time; tempron is preferred.

In recent years, aesthetic concerns regarding orthodontic appliances have significantly increased due to the growing number of adult patients undergoing orthodontic therapy. Clear removable aligners have seen growing popularity as an aesthetic and comfortable alternative to traditional fixed appliances. Clear aligner therapy also appears more respectful of the patient’s periodontal health; in fact, clear aligners allow the patients to maintain proper daily oral hygiene thanks to being removable. Among the parameters that affect the clinical efficacy of aligners, the material employed for their manufacturing plays a key role. The present paper aims to review the most used materials in manufacturing clear aligners, focusing on their clinical and mechanical performances, according to the current state of literature. Furthermore, biological features of the different materials are also examined regarding their effects on dental and periodontal tissues, oral mucosa, and potential systemic effects.

Clear aligner therapy (CAT) has gained popularity as an alternative to Conventional Orthodontic Treatments (COT) for its potential to reduce pain and discomfort. This systematic review and meta-analysis aimed to compare pain perception and surface electromyography (sEMG) in masticatory muscles between CAT and COT groups. A comprehensive search of multiple electronic databases was conducted to identify relevant studies. The PRISMA guidelines were employed to ensure transparency and completeness in reporting and was registered in PROSPERO (CRD42024556800). Nine studies were considered for inclusion. The meta-analysis revealed a nonsignificant difference in Visual Analog Scale scores between CAT and COT groups, with a mean difference (MD) of -2.77 (95% confidence interval [CI]: -7.25, 1.71), P = 0.23. The heterogeneity test revealed significant heterogeneity among studies (I² = 100%). In contrast, the sEMG activity scores showed a nonsignificant difference between CAT and COT groups (MD = -0.80, P = 0.60). In addition, the odds ratio for patients requiring analgesics was 0.23 (95% CI: 0.08, 0.65), P = 0.005, suggesting a significant difference between CAT and COT groups. The results suggest that CAT may be associated with improved patient outcomes, including reduced pain and discomfort, as well as lower analgesic consumption. However, the evidence is not conclusive, and further research is needed to fully understand the differences between CAT and COT.

Since the introduction of the Tooth Positioner (TP Orthodontics) in 1944, removable appliances analogous to clear aligners have been employed for mild to moderate orthodontic tooth movements. Clear aligner therapy has been a part of orthodontic practice for decades, but has, particularly since the introduction of Invisalign appliances (Align Technology) in 1998, become an increasingly common addition to the orthodontic armamentarium. An internet search reveals at least 27 different clear aligner products currently on offer for orthodontic treatment. The present paper will highlight the increasing popularity of clear aligner appliances, as well as the clinical scope and the limitations of aligner therapy in general. Further, the paper will outline the differences between the various types of clear aligner products currently available.

Aim: To evaluate the sorption, solubility and color change in two lining materials after 120 days of immersion in either sodium perborate or artificial saliva. Methods: Thirty disk-shaped specimens (15×3 mm) of each material, Mucopren(r) soft (MS) and Elite(r) soft (ES) were manufactured and divided into two groups. The specimens in the control group (CG, n=15) were stored in artificial saliva at 37 °C. The specimens in the experimental group (EG, n=15) were stored in artificial saliva at 37 °C and immersed in sodium perborate daily for 5 min. The analysis of sorption and solubility was based on the initial dry weight and on the wet and dry weights after immersion. The color was assessed with a portable spectrophotometer and the NBS system. ANOVA and Tukey test (p<0.05) were used to analyze color and sorption. The solubility was analyzed by KruskalWallis test (p<0.05). Results: Sorption was higher in the EG group (0.31±0.08) than in the control group (0.26±0.05), and higher in Elite(r) soft relining (0.34±0.07) than in Mucopren(r) soft (0.23±0.06). There was no interaction between the factors. Elite(r) Soft presented a higher solubility when immersed in artificial saliva (CG: 0.16±0.07 and EG: 0.13±0.06; p=0.00). Mucopren(r) soft showed no solubility in either treatment. Regarding the color changes, there was a significant difference between the groups (CG: 9.2±1.2 and EG: 9.9±1.2; p=0.025) but not between the materials (Mucopren(r) soft: 9.4±1.3 and Elite(r)soft: 9.7±1.0; p=0.34). Using the NBS system, we verified that both materials presented a high color change. Conclusions: The daily use of sodium perborate promoted changes in the liners' sorption and color. Elite(r) soft relining was more prone to changes than Mucopren(r) soft.