Patient survey on Invisalign® treatment comparing [corrected] the SmartTrack® material to the previously used [corrected] aligner material

Accuracy of arch expansion with two thermoplastic materials in Invisalign® patients: EX30® and SmartTrack®

OBJECTIVE

The purpose of this retrospective study was to compare accuracy of arch expansion using two different thermoplastic materials in Invisalign aligners: EX30® (Polyethylene Terephthalate Glycol, or PETG) and SmartTrack® (polyurethane).

METHODS

The study sample comprised 65 adult patients consecutively treated with Invisalign from two private practices: group 1 - treated with EX30® (358 teeth) and group 2 - treated with SmartTrack® (888 teeth). Six hundred and twenty-three measurements were assessed in three digital models throughout treatment: model 1 - initial, model 2 - predicted tooth position, and model 3 - achieved position. Sixteen reference points per arch were marked and, after best alignment, 2 points per tooth were copied from one digital model to another. Linear values of both arches were measured for canines, premolars, and first molars: on lingual gingival margins and cusp tips of every tooth. Comparisons were performed by Wilcoxon and Mann-Whitney test.

RESULTS

Both termoplastic materials presented significant differences between predicted and achieved values for all measurements, except for the lower molar cusp tip in the SmartTrack® group. There is no statistical difference in the accuracy of transverse expansion between these two materials. Overall accuracy for EX30® aligners in maxilla and mandible were found to be 37 and 38%, respectively; and Smarttrack® presented an overall accuracy of 56.62% in the maxilla and 68.72% in the mandible.

CONCLUSIONS

It is not possible to affirm one material expands better than the other. Further controlled clinical studies should be conducted comparing SmartTrack® and EX30® under similar conditions.

Clinical expression of programmed maxillary buccal expansion and buccolingual crown inclination with Invisalign EX30 and SmartTrack aligners and the effect of 1-week vs. 2-week aligner change regimes: A retrospective cohort study

Objective

: This retrospective cohort study aimed to assess and compare the accuracy of 3 different Invisalign® treatment regimens in terms of variations of aligner change frequency and type of aligner material in achieving maxillary dental buccal expansion.

Methods

: Altogether, 120 adult patients whose treatment involved maxillary dental expansion with Invisalign® were included. The patients were divided into 3 groups, with each group comprising 40 patients as follows: SmartTrack® 1-week changes (ST1), SmartTrack® 2-week changes (ST2), and EX30® 2-week changes (EX2). The groups were assessed by comparing actual changes achieved with those prescribed by ClinCheck®. The rates of clinically significant inaccuracies (CSI) observed for buccal expansion (≥ 0.5 mm) and buccolingual inclination (≥ 2°) during expansion were then determined.

Results

: In terms of expansion, the ST1 group demonstrated the highest CSI rate at all tooth levels, whereas the ST2 group had the lowest rate of CSI and the lowest mean inaccuracy for each tooth level. In terms of buccolingual inclination, the ST1 group had the highest CSI rate across all tooth levels, whereas the EX2 group had the lowest CSI rate at all tooth levels except for the canine level where the ST2 group had the lowest CSI rate. A tendency toward overexpression of buccal crown inclination, and underexpression of buccal expansion was observed at all tooth levels.

Conclusions

: Two-week aligner change regimens offer improved accuracy compared with 1-week aligner changes. SmartTrack® 2-week changes were the most accurate for buccal expansion, whereas EX30® 2-week changes were the most accurate for buccolingual inclination.

Impact of Invisalign G-series Updates on Improving Predicted Outcomes: A Retrospective Study

BACKGROUND

Understanding the real-world implications of periodic changes to orthodontic appliances can provide valuable insights for future treatment strategies and patient outcomes. This study aimed to investigate the impact of the latest updates added to the G7 and G8 Invisalign series on actual versus predicted outcomes and the percentage accuracy of the treatment.

METHOD

This retrospective study was conducted in private orthodontic practices in Riyadh, Saudi Arabia. Orthodontists carried out Invisalign® treatment using the latest updates added to the G7 and G8 Invisalign series. The study group comprised patients with different malocclusion types who received non-extraction Invisalign treatment. The Invisalign treatment plan was provided by the ClinChecks program (Invisalign, San Jose, United States) for patients treated throughout the years (2016-2022). Different dimensions were assessed to record predicted and actual treatment outcomes with the aid of iTero® (Align Technology, San Jose, United States) and ClinCheck® (Invisalign, San Jose, United States). The percentage accuracy was determined using the formula (100%-((Predicted-Actual)/Predicted) *100%).

RESULTS

A total of 108 patients (male = 34 (31.5%) and female = 74 (68.5%)) treated with Invisalign G7 and G8 series were considered in this study. The overall mean and standard deviation values of vertical distance (2.91±1.42), intermolar distance in the lower arch (52.68±3.15), overjet (2.71±1.06), and inter-incisal angle (138.24±12.18) were higher than the predicted model. However, the predicted model showed higher mean and standard deviation values for intercanine distances in the upper (36.94±1.57) and lower arches (28.48±1.40) and upper intermolar distances (57.21±2.91). The G7 versus G8 intercanine distance in lower (61.28±47.67 vs. 80.51±38.32), intermolar distance in upper (61.72±47.67 vs. 69.95±44.11), and intermolar distance in lower (100.68±3.80 vs. 100.89±2.52) were relatively higher in the G8 series than the G7. The accuracy percentage was higher with the G8 series than with the G7 regarding the intercanine distance in the upper arch. In contrast, the G7 series showed a higher mean percentage accuracy of vertical distance (91.11±84.83 vs. 76.76±65.45), overjet (58.44±35.17 vs. 53.71±45.87), and inter-incisal angle (34.47±44.06 vs. 27.53±37.98) than the G8 series.

CONCLUSION

The percentage accuracy of aligner therapy administered using the Invisalign G7 and G8 series demonstrated no significant variation.

Efficiency and Predictability of Coronal Maxillary Expansion Repercussion with the Aligners System: A Retrospective Study

The Invisalign® system (SmartForce® G8) aims to guarantee aesthetics and provide good orthodontic treatment results. Dentoalveolar expansion is possible with clear aligners and can be used to correct dentoalveolar crossbite, resolve crowding or modify the arch shape. Despite the treatment's effectiveness, there is still disagreement among professionals concerning its true clinical potential. This study aimed to analyze the effectiveness and predictability of coronal tooth expansion movement in permanent dentition in patients who had completed the first phase of treatment with Invisalign® orthodontic aligners.

MATERIALS AND METHODS

The tooth movement tables of 75 previously selected cases were analyzed in terms of dental-arch width and expansion efficiency, through the Invisalign® platform, considering the pre-treatment (T0), planned treatment (TP) and post-treatment models (T1) using ClinCheck Pro® 6.0 software. All patients were treated by an orthodontic specialist and Invisalign® Diamond Provider in a private practice (T.P.).

RESULTS

Difference between T1 and T0: for each maxillary and mandibular measurement, there was a statistically significant difference between pre- and post-aligner treatment values. The greatest amount of expansion occurred in both the upper and the lower premolars. Difference between TP and T1: for each maxillary measurement, statistically significant differences were verified for the molar and canine. At the mandibular level, statistically significant differences were only verified in the first molar.

CONCLUSIONS

The Invisalign® clear aligners are effective for simultaneous intra-arch expansion in both jaws.

Maxillary molar distalization with a 2-week clear aligner protocol in patients with Class II malocclusion: A retrospective study

INTRODUCTION

This study aimed to investigate the efficacy of molar distalization with or without anterior teeth retraction.

METHODS

Forty-three patients who received maxillary molar distalization with clear aligners were retrospectively enrolled and further divided into 2 groups: a retraction group (with maxillary incisor retraction ≥2 mm in ClinCheck) and a nonretraction group (without anteroposterior movement or with the labial movement of the maxillary incisor in ClinCheck). Pretreatment and posttreatment models were collected and laser-scanned to obtain the virtual models. Three-dimensional digital assessments of molar movement, anterior retraction and arch width were analyzed in the reverse engineering software Rapidform 2006. To calculate the efficacy of tooth movement, the achieved tooth movement assessed on the virtual model was compared with the predicted tooth movement in ClinCheck.

RESULTS

The achieved efficacy rates of molar distalization for the maxillary first and second molars were 36.48% and 41.94%, respectively. There was a significant difference in molar distalization efficacy between the retraction group (31.50% at the first molar and 35.63% at the second molar) and the nonretraction group (48.14% at the first molar and 52.51% at the second molar). In the retraction group, the efficacy of incisor retraction was 56.10%. The efficacy of dental arch expansion was more than 100% at the first molar levels in the retraction group and at the second premolar and first molar levels in the nonretraction group.

CONCLUSIONS

There is a discrepancy between the outcome and the predicted maxillary molar distalization with clear aligners. The efficacy of molar distalization with clear aligners was significantly affected by anterior teeth retraction, and the arch width significantly increased at the premolar and molar levels.

Advances in orthodontic clear aligner materials

Rapid technological improvements in biomaterials, computer-aided design (CAD) and manufacturing (CAM) have endorsed clear aligner therapy (CAT) as a mainstay of orthodontic treatment, and the materials employed for aligner fabrication play an all-important role in determining the clinical performance of clear aligners. This narrative review has attempted to comprehensively encompass the entire gamut of materials currently used for the fabrication of clear aligners and elucidate their characteristics that are crucial in determining their performance in an oral environment. Historical developments and current protocols in aligner fabrication, features of contemporary bioactive materials, and emerging trends related to CAT are discussed. Advances in aligner material chemistry and engineering possess the potential to bring about radical transformations in the therapeutic applications of CAT; in the absence of which, clear aligners would continue to underperform clinically, due to their inherent biomechanical constraints. Finally, while innovations in aligner materials such as shape memory polymers, direct three-dimensional (3D) printed clear aligners and bioactive materials combined with clear aligner materials are essential to further advance the applications of CAT; increased awareness of environmental responsibilities among aligner manufacturers, aligner prescribing clinicians and aligner users is essential for better alignment of our climate change goals towards a sustainable planet.

Effects of Multibracket Orthodontic Treatment versus Clear Aligners on Periodontal Health: An Integrative Review

Objective: This integrative review aimed to identify studies comparing the periodontal health in patients wearing multibracket orthodontic appliances and clear aligners. Materials and methods: An integrative literature search was performed through different databases, PubMed/Medline, PMC, and the Cochrane Library. This work was submitted to a search strategy following the PICO method and included the focus question: “Could the chosen orthodontic appliance change significantly the oral hygiene of the patient, impairing the periodontal health?” This work included analytical and controlled studies on humans published between 2005 and 2020, in the English language, establishing a comparison of the periodontal status in patients undergoing orthodontic multibracket and clear aligners therapies. The main periodontal indexes assessed were plaque index (PI), pocket depth (PD), gingival index (GI), and bleeding on probing (BoP). Results: The electronic research displayed 386 articles on PMC, 106 on PubMed, and 40 on the Cochrane Library. After removal, just 25 articles were selected for full-text screening, but just eight studies were eligible for this integrative review. It was enumerated that 204 patients were treated with aligners and 294 with multibracket orthodontic appliances, mainly elastomeric ligated brackets. Only the plaque index displayed a significant difference between the two groups and general data obtained showed a better control for periodontal health in the clear aligners. Limitations such as age, malocclusion severity, therapeutic choice, and different time measure was observed. In addition, the oral hygiene instruction and follow-up by a professional were different, and the role of malocclusion was not present in the studies. Conclusions: Within the limitations of this study, better results for periodontal health were found in the clear aligners. Therefore, more studies are necessary to affirm that aligners are synonymous with better gingival conditions in comparison with multibracket appliances. Other variables such as oral hygiene instructions, motivation, and supportive treatment tend to be more prevalent than the type of appliance itself in the periodontal evaluation.

Evaluation of the effectiveness of modified aligner appliance with nickel-titanium springs in treatment of mild crowding of lower incisors: A randomized controlled clinical trial

BACKGROUND

This study aimed to evaluate the effectiveness of modified aligner appliances with nickel-titanium springs (MAAs) in treating mild mandibular crowding and assess the overall alignment treatment duration, alignment improvement percentage, and mandibular incisor proclination.

METHODS

This two-armed, parallel-group randomized controlled trial included 36 patients (7 men, 29 women) with mild mandibular incisor crowding according to Little's Irregularity Index. Patients were randomly assigned to two groups: the MAA group (mean age = 22.56 ± 3.50 years) and the conventional fixed bracket group (control group; mean age = 20.89 ± 2.90 years). The duration of alignment treatment of the lower anterior teeth was calculated. The progress of alignment was evaluated every 2 weeks on the study casts, which were taken at fixed intervals: pretreatment (T0) and 2 (T1), 4 (T2), 6 (T3), and 8 (T4) weeks after beginning the treatment. Change of mandibular incisor proclination was evaluated by measuring and comparing pretreatment and postalignment lateral cephalograms.

RESULTS

No statistically significant difference was detected between the two groups in terms of alignment treatment duration (P = 0.097), whereas a significant difference was observed in the alignment improvement percentage at T1 (P = 0.000), T2 (P = 0.001), and T3 (P = 0.022). In addition, the MAA group had a lower change of mandibular incisor proclination than the control group (P = 0.000).

CONCLUSIONS

The clinical application of MAAs may be effective in lower incisor decrowding, with a reduction in lower incisor inclination compared with conventional fixed brackets. This trial was registered at ClinicalTrials.gov (identifier: NCT04988373).

Comparison of achieved and predicted crown movement in adults after 4 first premolar extraction treatment with Invisalign

INTRODUCTION

In this study, we compared achieved and predicted crown movements of maxillary and mandibular first molars, canines, and central incisors in adults after 4 first premolar extraction treatment with Invisalign.

METHODS

Seventeen adult patients who received 4 first premolar extraction treatment with Invisalign and completed the first series of aligners were included. Superimposition of pretreatment and actual posttreatment dental models was acquired using registrations of pretreatment and posttreatment craniofacial models on the basis of bone surfaces and registrations of craniofacial and dental models on the basis of dental crown surfaces, respectively. Superimposition of pretreatment and predicted posttreatment models was acquired from ClinCheck software. Achieved and predicted 3-dimensional crown movements of maxillary and mandibular first molars, canines, and central incisors were then compared using the paired t test.

RESULTS

Relative to predicted changes, first molars achieved greater mesial displacement, mesial tipping, and buccal inclination in both the maxilla and mandible, greater intrusion in the maxilla, and greater mesial-lingual rotation and less constriction in the mandible. Canines achieved greater distal tipping in both the maxilla and mandible, less retraction in the maxilla, and greater lingual inclination and extrusion in the mandible. Central incisors achieved greater distal tipping and lingual inclination and extrusion in both the maxilla and mandible and less retraction in the maxilla.

CONCLUSIONS

Tooth crown movements were not fully achieved as predicted following Invisalign treatment. Differences focused on mesial tipping, buccal inclination, mesial displacement, and intrusion of the first molars, as well as distal tipping, lingual inclination, insufficient retraction, and intrusion of the canines and central incisors.

Comparison of 2 Invisalign tray generations using the Peer Assessment Rating index

INTRODUCTION

This study aimed to establish if there is a significant difference in effectiveness between 2 generations of Invisalign trays in terms of Peer Assessment Rating (PAR) score reduction for finished patients from a graduate orthodontic clinic.

METHODS

Forty-five pretreatment and posttreatment patients treated with the previous Invisalign material and 49 pretreatment and posttreatment patients treated with SmartTrack material were scored using the Peer Assessment Rating (PAR) index. Both groups were controlled for initial weighted PAR score, age, gender, and treatment time. The 2 generations were compared in regard to absolute reduction, percent reduction, and great improvement in PAR score.

RESULTS

The mean absolute reduction in weighted PAR score between the groups was not statistically significant (P = 0.526). The mean percent reduction in weighted PAR score between the groups was not statistically significant (P = 0.210). The proportion of great improvement between the groups was not significant (P = 0.526). Only 6 of the 8 components of occlusion had enough variation to be modeled. An absolute reduction in unweighted PAR score was not significantly different between the groups for maxillary anterior alignment, overjet, or mandibular anterior alignment (P = 0.996, 1.000, and 0.114, respectively). Percent reduction in unweighted PAR score was not significantly different between the 2 groups for an anteroposterior, overbite, or transverse (P = 1.000, 1.000, and 1.000, respectively) relationships.

CONCLUSIONS

Our study indicates that both generations of Invisalign aligners improved the malocclusion to a similar degree according to the PAR index. Patient-centric benefits of SmartTrack aligner should also be considered by the provider.

Efficacy and predictability of maxillary and mandibular expansion with the Invisalign® system

Background

The purpose of this study is to evaluate the efficacy and predictability of upper and lower orthodontic expansion with the Invisalign® system.

Material and Methods

From a sample of 167 patients; 64 upper and 51 lower arches were randomly selected from patients who had been treated with plastic orthodontics (Invisalign® aligners, SmartTrack® material). Digital models were extracted at the beginning (ModT1) and at the end of treatment (ModT2) as well as the final ClinCheck® (CkT2). The canine, premolar and molar width was measured at the gingival and cuspid level of both arches, as well as the inclination of the upper first molar. Likewise, both arches were divided regarding the planned expansion at the level of the first molar into mild, moderate and severe.

Results

The efficacy of expansion in the upper and lower arches showed a statistically significant difference (p<0.00005). During the measurements of predictability, around 98-100% was achieved at the coronal level and between 85-90% at the gingival level. Analyzing predictability regarding to the magnitude of expansion, superior and inferior moderate expansion, both gingival and cuspid, presented higher values.

Conclusions

The Invisalign® system aligners (SmartTrack® material), proved to be a positive alternative for expansion movement offering high degree of predictability, both in the upper and lower arches. As a result, the most predictable level of expansion was moderate, having being the lower arch more foreseeable at the gingival level than the upper arch.

Key words:Predictability, Efficacy, Expansion, Aligner, Invisalign®.

SEM characterization and ageing analysis on two generation of invisible aligners

Background

The purpose of the in vitro study is to investigate and compare the morphological features and the chemical stability in weight of two different polyurethane-based blends, Smart Track (LD30) and Exceed30 (EX30), used for orthodontic aligners manufacture before and after the oral usage.

Methods

Twenty orthodontic aligners were randomly selected: 10 LD30 and 10 EX30, each group was divided in two subgroups, never used and intra-orally aged. By the employment of a Stereomicroscope, a section of 5 × 5 mm was cut from the buccal surface of the incisal region of each aligner. All samples were subjected to Scanning Electron Microscopy and Ageing tests in different solutions to simulate the hostility of the oral environment. The statistical method used was t-test.

Results

At SEM images, LD30 appears more homogeneous in texture respect to EX30. However, after clinical usage, both materials show significant structural alterations: findings have been supported by higher magnifications at SEM, by which it is clearly to observe many superficial cracks cross through the polymer structures of LD30U, absent in never used samples. LD30U surface becomes also smoother due to the disappearance of most of the conglomerates, but at the same time also rougher while EX30U shows a greater irregularity and porosity in which large and deep cracks are also highlighted. Although these changes occur persistently, in the aging tests no significant weight loss from both materials has been found, confirming the initial hypothesis of a good chemical stability and safety of both polyurethane mixtures even in conditions of severe hostility.

Conclusion

LD30 is the expression of the technological evolution of EX30, this is made evident above all by its morphological architecture, more homogeneous and defined but also by the chemical stability that can be appreciated even in evident critic situations.

ATR-FTIR Analysis of Orthodontic Invisalign® Aligners Subjected to Various In Vitro Aging Treatments

Clear and removable tooth aligners for orthodontics treatments have become an increasingly popular alternative to fixed appliances. Even if protocols suggest removing aligners before eating or drinking, most patients retain them when they drink beverages. Alterations in the material during the daily use could determine a reduction in the application forces, affecting the desired orthodontic movement; the knowledge of how this material reacts when subjected to different aging processes is mandatory to establish the predictability of the orthodontic treatment. According to this, the aim of the present study was to assess a new objective approach, coupling spectroscopic and chemometric tools, to evaluate the changes occurring in Invisalign^® aligners, the most widely used brand, exposed in vitro to coffee, tea, Coca Cola^® and UV radiation for 24 and 48 h. In particular, ATR-FTIR spectroscopy was utilized to characterize, at the molecular level, the chemical and color modifications in the surfaces of the appliances; the obtained data were submitted to PCA and one-way ANOVA and Tukey's multiple comparison test. Moreover, a colorimetry analysis was carried out to evaluate any changes in color and transparency. Coffee and tea samples displayed the major color changes between the tested groups. The differences highlighted in the spectral features of coffee, tea and UV-treated samples were mainly ascribable to color and transparency changes, because the chemical properties remained unaltered.

The periodontal status of removable appliances vs fixed appliances: A comparative meta-analysis

BACKGROUND

Although several researchers have analyzed the dental identity of patients experience with corrective methods using fixed and removable appliances, the consequences stay debatable. This meta-analysis intended to verify whether the periodontal status of removable appliances is similar to that of the conventional fixed appliances.

METHODS

Relevant literature was retrieved from the database of Cochrane library, PubMed, EMBASE, and CNKI until December 2019, without time or language restrictions. Comparative clinical studies assessing periodontal conditions between removable appliances and fixed appliances were included for analysis. The data was analyzed using the Stata 12.0 software.

RESULTS

A total of 13 articles involving 598 subjects were selected for this meta-analysis. We found that the plaque index (PLI) identity of the removable appliances group was significantly lower compared to the fixed appliances group at 3 months (OR = -0.57, 95% CI: -0.98 to -0.16, P = .006) and 6 months (OR = -1.10, 95% CI: -1.60 to -0.61, P = .000). The gingival index (GI) of the removable appliances group was lower at 6 months (OR = -1.14, 95% CI: -1.95 to -0.34, P = .005), but the difference was not statistically significant at 3 months (OR = -0.20, 95% CI: -0.50 to 0.10, P = .185) when compared with that of the fixed appliances group. The sulcus probing depth (SPD) of the removable appliances group was lower compared to the fixed appliances group at 3 months (OR = -0.26, 95% CI: -0.52 to -0.01, P = .047) and 6 months (OR = -0.42, 95% CI: -0.83 to -0.01, P = .045). The shape of the funnel plot was symmetrical, indicating no obvious publication bias in the Begg test (P = .174); the Egger test also indicated no obvious publication bias (P = .1).

CONCLUSION

Our meta-analysis demonstrated that malocclusion patients treated with the removable appliances demonstrated a better periodontal status as compared with those treated with fixed orthodontic appliances. However, the analyses of more numbers of clinical trials are warranted to confirm this conclusion.

Orthodontic treatment in National Dental Centre of Singapore: Trends toward higher proportion of adult patients

Background

Adult patients used to be daunted with the prospect of having fixed appliances to correct malocclusions. However, this has gradually changed and recent literature reported an increasing trend in adults receiving orthodontic treatment. To date, there has been no information regarding the trend of adult orthodontic patients in Singapore.

Objective

The objective of this study was to determine the changes in the proportion of adult patients seeking orthodontic treatment at the National Dental Centre Singapore (NDCS) from 2011 to 2017.

Materials and Methods

The study sample consists of all patients who commenced active orthodontic treatment from 2011 to 2017 at the NDCS. The data collected were analyzed for the number, gender, and proportion of adult orthodontic patients treated annually from 2011 to 2017. Linear-by-linear association test was used to test for any significant linear trend in proportion of adult orthodontic patients over the 7 years. Pearson’s Chi-squared test was used to test for any significant gender differences.

Results

There was a significant increasing linear trend (p = 0.001) in the proportion of adult orthodontic patients from 2011 to 2017. No significant difference (p = 0.770) between the proportions of male and female adults undergoing orthodontic treatment was found. The ages of adults undergoing orthodontic treatment ranged from 21 to 73 years old and majority (48.61%) of them was in the 21–25 years old age range.

Conclusion

There is a rising trend in adults seeking orthodontic treatment at the NDCS from 2011 to 2017. No statistically significant gender difference was observed in this rising trend.

Mechanical properties of "two generations" of teeth aligners: Change analysis during oral permanence

Aim of this in vitro study was to analyze structural properties of two different polymeric orthodontic aligners, Exceed30 (EX30) and Smart Track (LD30), before and after use. Forty patterns of aligners were randomly selected: 20 LD30 and 20 EX30, worn intra-orally for 14±3 days, 22 h/day. From each aligner, 10 specimens were prepared from buccal surfaces of the incisor region by the cutting of samples 5×5 mm under a stereomicroscope. All samples were subjected to Fourier transform infrared spectroscopy, micro-Raman spectroscopy, X-ray diffraction, tensile and indentation strength test. LD30 appeared more homogeneous, with a crystalline fraction lower than EX30 and exhibited a higher elastic behavior and a lower tendency to warp after use than EX30. LD30 demonstrated better adaptability to the dental arch and greater consistency of application of orthodontic forces than produced with EX30. However, both materials showed structural modifications that resulted in increased sample hardness and hyper-plasticity.

Assessment of the periodontal health status in patients undergoing orthodontic treatment with fixed appliances and Invisalign system: A meta-analysis

BACKGROUND

At present, many scholars have studied the periodontal health status of patients undergoing orthodontic treatment with fixed appliances and invisalign. However, those results are inconsistent. Therefore, we conducted this meta-analysis, and then provide reference for clinical treatment.

METHODS

Most databases, such as the Cochrane Library, EMBASE, PubMed, Medline, Chinese Biomedical Literature Database, CNKI, and Wan Fang Data were retrieved for related articles from the establishment of the database to October 2017. Meanwhile, we also searched the references of the related literatures manually, in order to increase the included literatures. Two researchers screened the related literatures according to the inclusion criteria and exclusion criteria. Stata 12.0 software was used for data analysis, and results are estimated by odds ratio (OR) and 95% confidence interval (CI).

RESULTS

Finally, 7 articles, including 368 patients, were included into our meta-analysis. Meta-analysis results showed that there was no statistically significant difference of gingival index (GI) and sulcus probing depth (SPD) status between the invisalign group and the control group, including at 1, 3, and 6 months (all P > .05). When compared with the control group, the invisalign group presented a lower plaque index (PLI) and sulcus bleeding index (SBI) status at 1 month (OR = -0.53, 95% CI: -0.89 to -0.18; OR = -0.44, 95% CI: -0.70 to -0.19, respectively), 3 months (OR = -0.69, 95% CI: -1.12 to -0.27; OR = -0.49, 95% CI: -0.93 to -0.05, respectively), and 6 months (OR = -0.91, 95% CI: -1.47 to -0.35; OR = -0.40, 95% CI: -0.63 to -0.07, respectively). Subgroup analysis showed that the SPD status was lower in the invisalign group at 6 months when measured the teeth using Ramfjord index (OR = -0.74, 95% CI: -1.35 to -0.12). However, there was no statistically significant difference between the 2 groups when using other measure methods (OR = 0.12, 95% CI: -0.26 to 0.17).

CONCLUSION

Our meta-analysis suggests that comparing with the traditional fixed appliances, patients treated with invisalign have a better periodontal health. However, more studies are needed to confirm this conclusion in the future.