Lingual vs. labial fixed orthodontic appliances: systematic review and meta-analysis of treatment effects

Effect of aligners on patients' oral health-related quality of life and anxiety: a prospective pilot study

BACKGROUND

This prospective study explored the impact of aligners on the oral health-related quality of life and anxiety of patients during the first month of orthodontic treatment and the first month of the retention phase.

METHODS

A total of 23 male and female patients (median age 25 y) treated with clear aligners were included. The OHRQoL questionnaire was used at certain time points during treatment (T1: placement of the first aligner; T2: after one day of use; T3: after seven days; T4: after one month; and T5: after one month in the retention phase). The State-Trait Anxiety Inventory (STAI) was also self-administered to assess state and trait anxiety (Y1 and Y2 subscales, respectively) at the T1, T4 and T5 time points. A population average generalized estimating equations logistic regression model was fit to assess the effect of time on the responses, and the Wald test was used to examine the overall effect of time.

RESULTS

Overall time was a significant predictor for most of the questions. However, time was marginally significant for the OHRQoL questions evaluating oral symptoms such as bad taste/smell, sores, and food accumulation. Tooth discolouration did not differ between time points. The general activity disturbance was significantly lower in the retention phase. Higher depression and anxiety scores were reported at the initial appointment and decreased thereafter.

CONCLUSIONS

CAT has a negative impact on quality of life and psychological status during the initial days of treatment. These impairments ameliorate at later treatment stages.

Cleaning performance of electric toothbrushes around brackets applying different brushing forces: an in-vitro study

Throughout treatment with fixed orthodontic appliances, effective plaque control is crucial to maintaining dental health. This in-vitro study evaluated the cleaning performance of eleven different brush heads of seven electric toothbrushes (oscillating-rotating and sonic motions) and varying brushing forces around orthodontic brackets. Six Mini Diamond® Twin brackets were placed on black-stained front teeth. Teeth were coated with white titanium oxide and brushed in a machine six times for one minute with two different brushing forces (1 N and 1.5 N). Eleven different brush heads were evaluated (either oscillating-rotating or sonic movements). The teeth were scanned and planimetrically evaluated after brushing. Three detailed plaque areas (DPAs) were created: proximal (< 1 mm to bracket), mid-tier (1-2 mm to bracket), and distant (> 2 mm to bracket). The proportion of contaminated proximal, mid-tier, and distant surfaces (white regions) in relation to the respective DPA was calculated. Independent of brushing forces, places with a higher distance (> 2 mm) to the orthodontic bracket had the least amount of residual contamination, followed by areas with a minor (1-2 mm) and proximal distance (< 1 mm). In all of the brushes tested and for both estimated brushing forces, the region with the highest residual contamination was the proximal area. The brush heads of the Paro® Sonic toothbrush left the least amount of residual contamination. The cleaning performance of electric toothbrushes around brackets on upper incisors varied across the brushes examined. The proximal area has the most residual contamination. Furthermore, 9 out of 11 toothbrushes cleaned more successfully with 1.5 N than with 1 N brushing force.

A Hypothesis Testing of Archwire Rounding for the Efficacy of Torque Springs in Orthodontics: A Finite Element Study

BACKGROUND

Achieving the proper buccolingual inclination of teeth is a cornerstone in orthodontic treatment, directly impacting the attainment of ideal occlusal relationships and long-term stability. A practical torque expression that moves the tooth in its proper position across all three planes is imperative to finish orthodontic cases optimally. The primary focus of this research is to investigate Burstone's hypothesis about Warren torque springs when applied to the rectangular wire. Additionally, it examines the hypothesis of rounding these wires in between the bracket wings of the target tooth to be moved. This study aims to determine whether the rounding of wires, in conjunction with the use of torque springs, influences orthodontic outcomes, addressing a notable gap in current literature and resolving controversies in orthodontic practice.

METHODS

A three-dimensional set of maxillary teeth was modeled. A 0.022" MiniSprint™ brackets and Stainless steel archwires of 0.019" × 0.025" and 0.017" × 0.025" (Forestadent, Pforzheim, Germany) were generated. Warren torque spring was modeled and used in the simulation on the upper right central incisor. Four case scenarios were simulated. In two scenarios, the archwires were untouched for both archwire sizes. In comparison, in the other two scenarios, each archwire size was rounded for the upper right maxillary incisor bracket area. Stresses in the Warren torque springs were calculated, the root tip displacement in the four scenarios was measured in millimeters, and both were analyzed.

RESULTS

The root tip displacement was highly affected by rounding the archwire. The increase in root tip displacement was 1538% for the Warren torque spring on 0.019" × 0.025" and 783% for 0.017" × 0.025". The amount of root tip displacement was about 18.8 mm for 0.017" × 0.025" with rounding and 12.2 mm for 0.019" × 0.025". The concentration of the stresses in the Warren torque spring was in the neck of the spring next to the coils.

CONCLUSION

Rounding the archwires while using the Warren torque spring on a rectangular archwire will increase the efficiency of the spring and, in turn, will exhibit more torque on the tooth. Smaller dimensions of rectangular archwires will give more torque in conjunction with Warren torque springs compared to larger sizes of archwires.

Accuracy of lingual straight-wire orthodontic treatment with passive self-ligating brackets and square slot: a retrospective study

OBJECTIVES

To investigate the accuracy of torque, tip and rotation and linear intra-arch movements yielded by passive self-ligating lingual straight-wire appliances with brackets featuring square slots.

MATERIALS AND METHODS

Twenty-five adult Caucasian patients (16 females and 9 males; mean age 26.5 ± 4.3 years) with Class I or mild Class II head-to-head malocclusion were orthodontically treated via passive lingual self-ligating straight-wire appliances (ALIAS, Ormco, Orange, CA) with no extraction. Records were retrospectively analysed, and digital models of pre-treatment (T0), planned (T1) and achieved (T2) phase were acquired for both arches in each patient via an intraoral scanner (Medit I500 (iScan Medit, Seoul, Korea). VAM software (Vectra, Canfield Scientific, Fairfield, NJ, USA) was used to measure both angular values (torque, tip and rotation) and linear intra-arch widths (between canines, first and second premolars and first and second molars). Measurements were obtained for all the movements investigated for each tooth group (incisors, canines, premolars and molars), by arch (maxillary and mandibular) and for both arches at T0, T1 and T2. The accuracy of angular values was compared using Student's t-test against a hypothetical 100%, and among the various tooth groups by post-hoc tests. Transverse linear measurements were investigated by means of the non-parametric Friedman test. The significance threshold was set at 0.05.

RESULTS

The mean accuracy of angular values was 77.25 ± 7.71% for torque, 78.41 ± 6.17% for tip and 77.99 ± 6.58% for rotation. In all cases, however, there was a significant difference between planned and achieved movements, and accuracy was significantly lower than the hypothetical 100% for all tooth groups, individual arches and dentition (p < 0.001). For intra-arch diameters, the greatest accuracy values were found for the anterior sectors (83.54 ± 5.19% for the maxillary inter-canine distance) and the lowest for the posterior sectors (67.28% for the maxillary inter-second molar distance).

CONCLUSION

Straight-wire lingual treatment with passive self-ligating appliances featuring with square slot displayed excellent clinical accuracy, albeit with statistical accuracy decreasing antero-posteriorly.

Pain profile during orthodontic levelling and alignment with fixed appliances reported in randomized trials: a systematic review with meta-analyses

OBJECTIVE

To assess the pain profile of patients in the levelling/alignment phase of orthodontic treatment, as reported from randomized clinical trials.

MATERIALS AND METHODS

Five databases were searched in September 2022 for randomized clinical trials assessing pain during levelling/alignment with a visual analogue scale (VAS). After duplicate study selection, data extraction, and risk-of-bias assessment, random effects meta-analyses of mean differences (MDs) and their 95% confidence intervals (CIs) were performed, followed by subgroup/meta-regression, and certainty analyses.

RESULTS

A total of 37 randomized trials including 2277 patients (40.3% male; mean age 17.5 years) were identified. Data indicated quick pain initiation after insertion of orthodontic appliances (n = 6; average = 12.4 mm VAS), a quick increase to a peak at day 1 (n = 29; average = 42.4 mm), and gradually daily decrease the first week until its end (n = 23; average = 9.0 mm). Every second patient reported analgesic use at least once this week (n = 8; 54.5%), with peak analgesic use at 6 h post-insertion (n = 2; 62.3%). Patients reported reduced pain in the evening compared to morning (n = 3; MD =  - 3.0 mm; 95%CI =  - 5.3, - 0.6; P = 0.01) and increased pain during chewing (n = 2; MD = 19.2 mm; 95% CI = 7.9, 30.4; P < 0.001) or occlusion of the back teeth (n = 2; MD = 12.4 mm; 95% CI = 1.4, 23.4; P = 0.3), while non-consistent effects were seen for patient age, sex, irregularity, or analgesic use. Subgroup analyses indicated increased pain among extraction cases and during treatment of the lower (rather than the upper) arch, while certainty around estimates was moderate to high.

CONCLUSIONS

Evidence indicated a specific pain profile during orthodontic levelling/alignment, without signs of consistent patient-related influencing factors.

Mandibular asymmetry retreatment with minimal presurgical orthodontic preparation and fully customized lingual orthodontics: A case report with new possibilities using blender open-source software

New possibilities such as Surgery-first and Minimal Presurgical Orthodontics have become extra alternatives for patients, orthodontists, and oral and maxillofacial surgeons, with immediate facial improvements, reduced preparation time, and shorter treatment time. The purpose of this case report was to demonstrate the retreatment of a female patient, dissatisfied with the instability of the compensatory orthodontic treatment, chin deviation, and forward inclination of the maxillary incisors, which was successfully treated with Minimal Presurgical Orthodontic approach associated with customized lingual brackets and virtual planning on the open-source Blender 3D software, where the post-surgical maxillary lingual brackets were also designed. Orthodontic preparation was performed in 5 months. After surgery, orthodontic treatment was finished with the aid of mini-implants and miniplates. The total treatment time was 18 months. Great facial and occlusal results were obtained and the patient was satisfied. Overall, all treatment steps were performed following a digital workflow and open-source software. It is possible to conclude that Minimal Presurgical Orthodontic Preparation was an excellent alternative for the retreatment of this patient with mandibular asymmetry and increased treatment expectations. Additionally, the surgical planning and design of lingual braces with open-source software can be considered useful and low-cost alternatives for orthodontists.

Digital lingual appliance combined with micro-screws for the treatment of a skeletal bimaxillary protrusion and ‘gummy’ smile

This case report describes the lingual orthodontic treatment of a 28-year-old female patient who presented with a bimaxillary protrusion malocclusion, a hyperdivergent facial pattern, mentalis strain, and a ‘gummy’ smile. To achieve favourable occlusal and facial results, the four first premolars were extracted, and micro-screws utilised to provide maximum anchorage. With the widespread application of three-dimensional technology, a digital goal-oriented treatment plan was applied for its predictability and precision. A fully customised lingual appliance system with preset torque in the anterior teeth combined with ribbon-wise arch wires was placed to prevent excessive lingual inclination of the incisors during retraction. As a result, an attractive facial profile and a well-aligned dentition with ideal intercuspation was obtained.

Increased demand for orthodontic treatments during the COVID-19 pandemic: a commentary

Despite the impact of the COVID-19 pandemic upon healthcare sectors generally, and what this continues to mean in particular for the practice of dentistry, there is evidence of an unanticipated upsurge in the demand for orthodontic treatment. This was observed in the UK and internationally as a manifestation of the so-called 'Zoom boom', in which video conferencing from home on various platforms suddenly exponentiated. As a result, it seems people became more self-conscious when viewing their appearance on-screen. Among the precipitating factors for individuals taking the consequent step of seeking orthodontic treatment are: the unavailability of more invasive smile enhancement treatments due to the pandemic restrictions; a more favourable infection control probability in orthodontic therapy; and the extra disposable funds that would otherwise be spent on holidays and leisure activities. This article explores different possible social and commercial drivers behind this phenomenon and suggests that the circumstances of the pandemic have shifted the pursuit of the desirable smile somewhat towards orthodontics, and as a consequence, is beneficial both to the public and the profession of dentistry as a whole.

Management of white spot lesions induced during orthodontic treatment with multibracket appliance: a national-based survey

OBJECTIVES

The study aimed to survey current strategies against enamel demineralization during multibracket therapy (MBT) and guide a prevention concept based on existing scientific evidence.

MATERIALS AND METHODS

The survey comprised questions on the prevention and management of white spot lesions (WSL). The questionnaire was sent via email to orthodontists working in practices and universities throughout Germany. The analysis involved descriptive statistics using the chi-square test (p < 0.05).

RESULTS

A prevention protocol was used before MBT by 80.6% of the participants. Less than a quarter of the participants regularly applied topical fluoride (gel or varnish) during MBT. According to the respondents' assessment, the prevalence of WSL during MBT is 11.6%, mainly observed in 12- to 15-year-old male patients. Orthodontists graduating after 2000 tended to recommend and apply fluoride-containing materials more often than their senior colleagues (p = 0.039). Participants from private practices applied fluoride varnish or gel more frequently than those from university clinics (p = 0.013). Fluoridation was the most common (70.7%) treatment for WSL after MBT, followed by resin infiltration (21.2%). The majority (80.9%) of the participants favor a guideline for preventing WSL.

CONCLUSIONS

WSL prevention during MBT is challenging. Males in puberty are predominantly affected. Younger orthodontists are more concerned about the prevention of WSL during MBT.

CLINICAL RELEVANCE

The non-negligible prevalence of individuals with WSL emphasizes the need for dental education and health care reform. This would help to implement standardized procedures and establish innovative applications.

Effect of periodontal-orthodontic treatment of teeth with pathological tooth flaring, drifting, and elongation in patients with severe periodontitis: A systematic review with meta-analysis

AIM

To assess the beneficial and adverse effects on the dental and periodontal issues of periodontal-orthodontic treatment of teeth with pathological tooth flaring, drifting, and elongation in patients with severe periodontitis.

MATERIALS AND METHODS

Nine databases were searched in April 2020 for randomized/non-randomized clinical studies. After duplicate study selection, data extraction, and risk-of-bias assessment, random-effect meta-analyses of mean differences (MDs) and their 95% confidence intervals (CIs) were performed, followed by subgroup/meta-regression analyses.

RESULTS

A total of 30 randomized and non-randomized clinical studies including 914 patients (29.7% male; mean age 43.4 years) were identified. Orthodontic treatment of pathologically migrated teeth was associated with clinical attachment gain (-0.24 mm; seven studies), pocket probing depth reduction (-0.23 mm; seven studies), marginal bone gain (-0.36 mm; seven studies), and papilla height gain (-1.42 mm; two studies) without considerable adverse effects, while patient sex, gingival phenotype, baseline disease severity, interval between periodontal and orthodontic treatment, and orthodontic treatment duration affected the results. Greater marginal bone level gains were seen by additional circumferential fiberotomy (two studies; MD = -0.98 mm; 95% CI = -1.87 to -0.10 mm; p = .03), but the quality of evidence was low.

CONCLUSIONS

Limited evidence of poor quality indicates that orthodontic treatment might be associated with small improvements of periodontal parameters, which do not seem to affect prognosis, but more research is needed.

A Simple Technique Using a Modified Nance Appliance as Anchorage for Maxillary Molar Distalization—Two Case Reports

Maxillary molar distalization to correct a dental Class II molar relationship and to create space to relieve crowding has been a long-lasting subject of debate in orthodontics. Generally, to distalize maxillary molars, an intra-arch distalization appliance is favored over an inter-arch appliance since it does not utilize mandibular dentition as an anchorage, so some unwanted side effects on mandibular incisors can be avoided. A variety of intra-arch appliances have been developed to distalize maxillary molars, such as the pendulum, Jones jig, first class appliance, distal jet, and modified C-palatal plate. Although they could achieve efficient molar distalization, the learning curve of proper appliance insertion and activation is relatively long. In addition, the appliances are not comfortable for the patients due to the bulky activation units, especially when the activation units are designed in the palatal area. The current manuscript describes a novel and effective maxillary intra-arch molar distalization appliance—a modified Nance appliance technique, which consists of: (1) palatally, a big acrylic button against the palatal rugae and connected to the premolars with wide mesh pads; (2) buccally, regular brackets on maxillary premolars and first molars with sectional round stainless steel archwires and open coil springs between the second premolar and first molar. Either bilateral or unilateral maxillary molar distalization can be achieved with this appliance, and the Class II elastics are not needed. It is simple to be fabricated, delivered, and activated, and it is comfortable for patients.

Treatment of Class II malocclusion with a customized lingual appliance combined with a Class II corrector

Correcting a complete Class II malocclusion in an adult patient can be quite difficult. If the patient has a large skeletal discrepancy, orthognathic surgery is the treatment of choice. However, if the discrepancy is small or if the situation is borderline and the mandibular incisors are retroclined, Class II correctors can be used. This clinical report presents the orthodontic treatment of a 24-year-old woman with Class II malocclusion. Clinically, her maxilla was slightly protruded, and the mandible was well-positioned. She had uprighted maxillary and mandibular anterior teeth and a deepbite, and she opted for a more esthetically appealing orthodontic appliance. The treatment plan included leveling and alignment of the teeth in both arches, Class II correction, establishing Class I molar and canine relationships, correction of overbite and overjet, adjustment of midlines, and improvement of facial and dental esthetics. Orthodontic treatment consisted of customized lingual appliances combined with a Class II fixed corrector.

Clear aligner VS fixed self-ligating appliances: Orthodontic emergency during 2020 COVID-19 pandemic

Introduction

The aim was to investigate the type, incidence, and degree of orthodontic-related emergencies in orthodontic patients during the 2020 coronavirus disease 2019 pandemic and compare the different effects of clear aligner (CA) and fixed self-ligating appliances on the orthodontic emergency.

Methods

The questionnaire was based on emergencies in orthodontics. The responses of 428 patients between the ages of 12 and 38 years (20.4 ± 7.03) in orthodontic treatment during 2020 were examined.

Results

The gender, age, and the type of orthodontic appliance affect the incidence of orthodontic-related emergencies. Female or adolescent patients treated by self-ligating appliances showed a higher incidence of emergencies. The patients treated by CA exhibited a much lower incidence of emergency. Appliance detachment and mucosa injury were very common in respondents, whereas accidental ingestion and other rare emergencies were less common. The most common reason leading to appliance detachment was chewing hard food. Interestingly, the fixed self-ligating appliances group was also affected by the accidental detachment of appliances to a large extent. The CA and self-ligating groups showed an almost equal incidence of accidental ingestion. The most common foreign body was elastics in both groups. However, the self-ligating group could accidentally ingest dangerous foreign bodies, such as archwires, miniscrews, and welded attachments.

Conclusions

Orthodontic-related emergencies were very common in patients. The CA could effectively reduce orthodontic-related emergencies. Dentists should raise patients’ awareness of proper appliance care. A proper and standard protocol should be developed.

Comparative analysis of growth factors and chemokine secretions between conventional lingual and labial fixed orthodontic appliances

Background

Orthodontic appliances elicit the secretions of some cytokines, chemokines, and growth factors which further have some significances in the remodeling of periodontium tissues. The significant differential forces applied on the periodontium by different types of orthodontic appliances. The secretion of these factors is indirectly responsible for the proper resorption of bones of the periodontal region through molecular signaling, which further supports to facilitate organized movement of the teeth. Objective: In the present study, we carried out the assessment and comparative analysis of the growth factors and chemokines present in the saliva samples of the human subjects of orthodontic treatment with two different treatment modalities: conventional lingual and labial fixed orthodontic appliances.

Materials and Methods

Total 40 saliva samples were collected of which 20 subjects were treated with the conventional lingual appliances and 20 subjects with the labial fixed appliances. All the salivary samples were acquired from the subjects after 21 days treatment. Cytometric bead array was performed to assess the growth factors and chemokines in the saliva on the flow cytometer.

Results

No significant differences were seen in the growth factor secretion in the saliva of both types of subjects. The same trend was observed for the chemokine secretion in the saliva except CXCL8, CCL11, CCL2, CCL5, and CXCL9.

Conclusion

The similarity in chemokine and growth factor profile between labial and lingual fixed orthodontic appliances indicates that their molecular mechanisms and overall effect on the periodontium are analogous.

Effects of orthodontic treatment with aligners and fixed appliances on speech

OBJECTIVES

To evaluate effects of orthodontic treatment with aligners and conventional fixed appliances on production of speech.

MATERIALS AND METHODS

This was a parallel, randomized clinical trial. Patients with Angle Class I malocclusion, moderate crowding, and no speech impairment were randomly allocated to two groups: patients with orthodontic aligners (OAs; n = 20; mean age = 23.60 ± 5.65 years) and those with conventional fixed appliances (n = 20; mean age = 20.56 ± 4.51 years) and treated at the University of North Parana's clinic in Londrina, Brazil. Evaluation of speech production was performed semiobjectively by a speech therapist (myofunctional orofacial examination) and subjectively (self-assessment) at five time points: baseline, immediately after insertion of appliances, and subsequently at 3, 30, and 180 days after insertion. For intergroup comparison, independent t, χ2, Fisher exact, and Mann-Whitney tests were used; for intragroup comparison, the Friedman test was applied (α = 5%).

RESULTS

In the semiobjective evaluation, patients with OAs exhibited a change in production of speech production, compared with patients with fixed appliances, immediately and 3 days after insertion of appliances (P < .001). Thirty days after insertion, the groups were similar (P = .487), an outcome that was unchanged at 180 days. However, in the self-assessments, patients in both groups reported significant speech difficulties immediately and 3 days after insertion of appliances, but such impairment was no longer perceived at 30 days or 180 days.

CONCLUSIONS

Although the speech therapist identified changes in speech production at the start of treatment in the OA group only, patient self-assessments demonstrated that orthodontic treatment, regardless of the type of appliance used, interfered with their perception of speech.

How efficient is customized lingual orthodontics? An assessment of treatment outcome

OBJECTIVE

To assess the efficacy of lingual orthodontics by comparing setups and post-treatment casts.

SETTING AND SAMPLE POPULATION

Thirty-two consecutive patients treated with a customized lingual orthodontic appliance were included in this retrospective study.

MATERIALS AND METHODS

Initial casts, post-treatment casts and setups were scanned, and the digital models produced were analysed in terms of overjet; overbite; molar and canine relationships; intercanine, interpremolar and intermolar distances; upper and lower arch lengths; midline deviation; bucco-lingual angulation of all teeth and mesio-distal angulation of anterior teeth. Comparisons between setups and post-treatment casts were performed via paired t tests. Relationships between the planned and actual correction were studied using regression analysis.

RESULTS

Statistically significant differences in bucco-lingual torque between setups and post-treatment casts were found for all upper teeth, except for central incisors. In the lower jaw, statistically significant differences in bucco-lingual torque were found between setups and post-treatment casts for the lower incisors and molars. No statistically significant differences in mesio-distal angulation of anterior teeth were found between setups and post-treatment casts. Upper and lower arch widths did not vary significantly between setups and final casts, except upper inter-second premolar and intermolar distances.

CONCLUSION

Customized lingual appliances offer efficient control of mesio-distal angulation of all anterior teeth. Significant differences in torque between setups and post-treatment casts were observed for upper lateral incisors, canines, premolars and molars, as well as lower incisors and molars. However, the torque difference was clinically significant (over three degrees) for upper second premolars and molars only.

Assessment of salivary pro inflammatory cytokines profile level in patients treated with labial and lingual fixed orthodontic appliances

The secretions of certain cytokines, chemokines and growth factors are triggered by orthodontic appliances, which often affect the remodelling of periodontal tissues. Critical cumulative forces are applied by various types of orthodontic appliances to the periodontium. The secretion of such molecules is probably responsible, through molecular and cellular communications, for the optimal resorption of hard tissues in the periodontal setting, which therefore enables the coordination of multiple movements of tooth. This study assessed and compared a wide range of cytokines, cellular marker analysis and defensins present in the saliva samples of human subjected to orthodontic treatment with two different treatment modalities, i.e., conventional lingual and labial fixed orthodontic appliances. A total 40 samples of saliva were obtained, of which 20 were treated with traditional lingual appliances and 20 were treated with labial fixed appliances. After 21 days of treatment, all salivary samples were collected from the subjects. In order to analyse a broad range of soluble cytokine levels in saliva by flow cytometry, a bead-based immunoassay was performed. Cell surface markers were analysed by flow cytometry. Protein levels of saliva for defensins were quantified by ELISA. Non-significant differences were observed in the cytokine levels in the saliva except for the significant effects for CCL2, IL-17A and IL-6. Cellular markers CD45 and CD326 showed high percentage in conventional lingual samples. Defensin levels were found to be lower in conventional lingual patients. Subjects with conventional lingual appliances had significantly higher salivary protein levels of IL-1β, CCL2, IL17A, and IL-6, higher CD45+ and CD326+ cells and lower defensin levels than subjects with fixed labial appliances. The current study provided a clear basis for the development of innovative methods to aid in the improvement of various procedural treatments and orthodontic equipment of next generation.

Reasons influencing the preferences of prospective patients and orthodontists for different orthodontic appliances

Objective

To evaluate the reasons influencing the preferences for a certain type of orthodontic appliance over another among prospective patients (PP) and orthodontists.

Methods

A total of 49 PP and 51 orthodontists were asked about their preferences for the following appliances clear aligners (CA), lingual metallic brackets (LMB), polycrystalline and monocrystalline ceramic brackets, and buccal metallic brackets (BMB). The participants rated the importance of 17 potential reasons that would explain their choices. The reasons that contributed most to these preferences were identified. Non-parametric tests (Fisher’s exact, χ² and Mann–Whitney tests) and multivariate analyses (regression and discriminant analysis) were used to assess the data (α = 0.05).

Results

CA and BMB were the most chosen appliances by PP and orthodontists, respectively. LMB was the most rejected option among both groups of participants (p < 0.001). Rates of the importance of pain/discomfort, smile esthetics, finishing details, and feeding/speech impairment showed the highest differences between PP and orthodontists (p < 0.0005). Discriminant analyses showed that individuals who considered treatment time and smile esthetics as more important were more likely to prefer CA, while those who prioritized finishing details and cost were more likely to choose BMB (p < 0.05).

Conclusions

Reasons related to comfort and quality of life during use were considered as more important by PP, while those related to the results and clinical performance of the appliances were considered as more relevant by orthodontists.

Oral Impacts Experienced by Orthodontic Patients Undergoing Fixed or Removable Appliances Therapy in Saudi Arabia: A Cross-Sectional Study

PURPOSE

The objective of this study is to compare the orthodontic patient's experiences with removable and fixed orthodontic appliances on daily activities, food consumption, and oral symptoms in Riyadh city, Saudi Arabia.

METHODS

This was a cross-sectional observational study carried out among orthodontic patients. A total of 150 adult patients, including 118 in the fixed orthodontic appliance group and 32 in the removable (Invisalign) orthodontic group, who met the inclusion criteria completed a validated and self-administered questionnaire. In addition, the study participants reported their experience in terms of daily routine, food consumption, and oral symptoms one week after appliance activation. Data were analyzed using the chi-square test and Fisher's exact tests for the categorical variables. In addition, Mann-Whitney U, Kruskal-Wallis, and Spearman's tests were also applied to the data.

RESULTS

The fixed orthodontic patients compared to the removable orthodontic cases showed significantly higher difficulty in sleeping (1.28±1.10 vs 0.94±0.88, p=0.024), sores on the tongue (0.97±1.00 vs 0.56±0.76, p=0.042) and cheeks (1.20±1.11 vs 0.72±0.81, p=0.027), and the presence of food debris under the appliance (1.53±1.16 vs.1.00±0.95, p=0.021). Moreover, the oral health impact score showed a significant positive correlation with the duration of the orthodontic treatment (r=0.339, p<0.001) and pain intensity (r=0.309, p<0.001).

CONCLUSION

The fixed orthodontic treatment compared to removable orthodontic treatment resulted in more severe pain, sleeping difficulty, sores on the tongue and cheeks, and food impaction after one week of appliance activation.

Pain and Oral-Health-Related Quality of Life in Orthodontic Patients During Initial Therapy with Conventional, Low-Friction, and Lingual Brackets and Aligners (Invisalign): A Prospective Clinical Study

The aim of this study was to compare pain and its relationship with the oral quality of life of patients with different types of orthodontic appliances: conventional and conventional low-friction brackets, lingual brackets, and aligners. A prospective clinical study was carried out with a sample size of 120 patients (54 men, 66 women) divided into 4 groups of 30 patients each. The modified McGill questionnaire was used to measure pain at 4, 8, and 24 h and 2, 3, 4, 5, 6, and 7 days after the start of treatment, and the Oral Health Impact Profile-14 (OHIP-14) questionnaire was used to measure the oral-health-related quality of life (OHRQoL) in the first month of treatment. The maximum peak of pain was obtained between 24 and 48 h of treatment. It was found that patients in the lingual orthodontic group described lower levels of pain at all times analyzed, and their scores in the total OHIP-14 indicated less impact on their oral quality of life (1.3 ± 1.2, p < 0.01) compared with the other groups analyzed. There was little difference with the aligners group (Invisalign) (1.7 ± 1.9, p < 0.01). The technique used influences the pain and quality of life of patients at the start of orthodontic treatment.

Is there a need to increase palatal root torque of upper incisors in lingual appliance? A finite element analysis

Objectives:

Methodology:

Results:

Conclusion:

Enamel Surface Roughness after Lingual Bracket Debonding: An In Vitro Study

The aim of the present study was to quantitatively assess changes in enamel roughness parameters before and after lingual bracket debonding. The lingual surface of 25 sound premolars extracted for orthodontic reasons was studied by 3D optical interferometric profilometry before and after debonding of lingual brackets following enamel finishing (with fine diamond) and polishing (with 12- and 20-fluted carbide burs). The roughness parameters tested were the amplitude parameters Sa and Sz, the hybrid parameter Sdr, and the functional parameters Sc and Sv. The parameter differences (after debonding-reference) were calculated, and statistical analysis was performed via a Wilcoxon signed-rank test. Statistically significantly higher values were observed in all the surface roughness parameters of enamel surfaces after finishing and polishing, with the mostly affected parameter being the Sdr. Under the conditions of the present study, the finishing and polishing instruments used after debonding of lingual noncustomized brackets created a surface texture rougher than the control in all the tested roughness parameters.

Lingual Orthodontic Treatment: Efficacy and Complications

Aims and Objectives:

The high esthetic demands led to the promotion of various esthetic appliances like lingual orthodontics. This study aimed to review clinical outcome and potential complications of lingual orthodontics to achieve an evidence-based decision for orthodontic therapies.

Materials and Methods:

A comprehensive electronic search was conducted from January 1975 to March 2019 which was limited to English language and administrations of lingual orthodontics treatment which evaluated its efficacy and potential complications. Data extraction was performed according to the PRISMA statement.

Results:

49 studies were selected and analyzed in this systematic review. The pain of lingual appliances starts a little earlier and lasts longer, and patients with lingual appliances experience more tongue discomfort and less cheek and lip pain and greater eating difficulties especially after placement and take a longer time to adapt to appliances. Lingual appliances generally cause more plaque accumulation and gingivitis especially in lingual anterior teeth; however, labial appliances are associated with high frequency in posterior maxillary teeth.

Conclusion:

This systematic review shows that despite the drawbacks of these appliances such as pain and eating difficulties, they can accomplish treatment goals with the same outcomes in comparison with conventional approaches, within the same duration and even lesser anchorage loss.

Systematic reviews in orthodontics: Impact of the PRISMA for Abstracts checklist on completeness of reporting

INTRODUCTION

This study evaluated and compared the completeness of reporting of abstracts of orthodontics systematic reviews before and after the publication of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) extension for Abstracts Checklist (PRISMA-A).

METHODS

Abstracts of systematic reviews and meta-analyses in orthodontics published in PubMed, Latin American and Caribbean Health Sciences Literature, and the Cochrane Database of Systematic Reviews databases before March 23, 2018, that met the predefined inclusion and exclusion criteria, were evaluated using the 12 items of PRISMA-A, scoring each item from 0 to 2. Abstracts were classified into 2 groups: before and after publication of the PRISMA-A checklist. Three calibrated evaluators (intraclass correlation coefficient and kappa > 0.8) assessed the scores for compliance with the checklist. The number of authors, country of affiliation of the first author, performance of meta-analysis, and topic of the article were recorded. A regression analysis was performed to assess the associations between abstract characteristics and the PRISMA-A scores.

RESULTS

Of 1034 abstracts evaluated, 389 were included in the analysis. The mean PRISMA-A score was 53.39 (95% CI, 51.83-54.96). The overall score for studies published after the publication of the checklist was significantly higher than for studies published before (P ≤ 0.0001). The components returning significantly higher scores after publication of PRISMA-A were title (P = 0.024), information from databases (P = 0.026), risk of bias (P ≤ 0.0001), included studies (P ≤ 0.0001), synthesis of results (P ≤ 0.0001), interpretation of results (P = 0.035), financing and conflict of interest (P ≤ 0.0001), and registration (P ≤ 0.0001). These results showed the positive effect of PRISMA-A had on the quality of reporting of orthodontics systematic reviews. Nevertheless, the poor adherence revealed that there is still need for improvement in the quality of abstract reporting.

CONCLUSIONS

The quality of reporting of abstracts of orthodontic systematic reviews and meta-analyses increased after the introduction of PRISMA-A.

Lingual orthodontics in an adult patient with upper premolar extraction: Case report

OBJECTIVE

To show with this case report that lingual orthodontics can be a solution in complex adult situation and with interdisciplinary approach.

MATERIALS AND METHODS

The patient presented a dental and skeletal high angle class II division 1 with a previous extraction of one mandibular incisor. The strategy of treatment was upper first premolar-extraction to obtain a correction of the incisal-class II relationship with a normal lip function, a class II molar relationship on the right side and a class I on the left side. A lingual appliance and miniscrews were used.

RESULTS

The lingual orthodontic treatment with miniscrews responded to the occlusal objectives with a good upper incisors torque and retraction control.

DISCUSSION

Limits and advantages of lingual orthodontics were discussed.

CONCLUSION

Lingual mechanics can provide good results from both an aesthetic and function point of view in adult complex extractions case. It ensures aesthetics during treatment, incisor control during retraction. Miniscrews were also useful to overcome the periodontal limits and enhance the anchorage.

Speech and orthodontic appliances: a systematic literature review

Background

Various types of orthodontic appliances can lead to speech difficulties. However, speech difficulties caused by orthodontic appliances have not been sufficiently investigated by an evidence-based method.

Objectives

The aim of this study is to outline the scientific evidence and mechanism of the speech difficulties caused by orthodontic appliances.

Search methods and selection criteria

Randomized-controlled clinical trials (RCT), controlled clinical trials, and cohort studies focusing on the effect of orthodontic appliances on speech were included. A systematic search was conducted by an electronic search in PubMed, EMBASE, and the Cochrane Library databases, complemented by a manual search.

Data collection and analysis

The types of orthodontic appliances, the affected sounds, and duration period of the speech disturbances were extracted. The ROBINS-I tool was applied to evaluate the quality of non-randomized studies, and the bias of RCT was assessed based on the Cochrane Handbook for Systematic Reviews of Interventions. No meta-analyses could be performed due to the heterogeneity in the study designs and treatment modalities.

Results

Among 448 screened articles, 13 studies were included (n = 297 patients). Different types of orthodontic appliances such as fixed appliances, orthodontic retainers and palatal expanders could influence the clarity of speech. The /i/, /a/, and /e/ vowels as well as /s/, /z/, /l/, /t/, /d/, /r/, and /ʃ/ consonants could be distorted by appliances. Although most speech impairments could return to normal within weeks, speech distortion of the /s/ sound might last for more than 3 months. The low evidence level grading and heterogeneity were the two main limitations in this systematic review.

Conclusions

Lingual fixed appliances, palatal expanders, and Hawley retainers have an evident influence on speech production. The /i/, /s/, /t/, and /d/ sounds are the primarily affected ones. The results of this systematic review should be interpreted with caution and more high-quality RCTs with larger sample sizes and longer follow-up periods are needed.

Registration

The protocol for this systematic review (CRD42017056573) was registered in the International Prospective Register of Systematic Reviews (PROSPERO).

Lingual Fixed Orthodontic Appliances May Be Associated With More Adverse Effects Than Buccal Appliances

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION

Adverse effects of lingual and buccal orthodontic techniques: A systematic review and meta-analysis. Ata-Ali F, Ata-Ali J, Ferrer-Molina M, Cobo T, De Carlos F, Cobo J. Am J Orthod Dentofacial Orthop 2016; 149:820-9.

SOURCE OF FUNDING

Not stated.

TYPE OF STUDY/DESIGN

Systematic review and meta-analysis.

Registered trials report less beneficial treatment effects than unregistered ones: a meta-epidemiological study in orthodontics

OBJECTIVES

Clinical trial registration is widely recommended because it allows tracking of trials that helps ensure full and unbiased reporting of their results. The aim of the present overview was to provide empirical evidence on bias associated with trial registration via a meta-epidemiological approach.

STUDY DESIGN AND SETTINGS

Six databases were searched in September 2017 for randomized clinical trials and systematic reviews thereof assessing the effects of orthodontic clinical interventions. After duplicate study selection and data extraction, statistical analysis included a two-step meta-epidemiological approach within- and across-included meta-analyses with a Paule-Mandel random-effects model to calculate differences in standardized mean differences (ΔSMD) between registered and unregistered trials and their 95% confidence intervals (CI), followed by subgroup and sensitivity analyses.

RESULTS

A total of 16 meta-analyses with 83 trials and 4,988 patients collectively were finally included, which indicated that registered trials reported less beneficial treatment effects than unregistered trials (ΔSMD = -0.36; 95% CI = -0.60, -0.12). Although some small-study effects were identified, sensitivity analyses according to precision and risk of bias indicated robustness.

CONCLUSION

Signs of bias from lack of trial protocol registration were found with nonregistered trials reporting more beneficial intervention effects than registered ones. Caution is warranted by the interpretation of nonregistered randomized trials or systematic reviews thereof.

Soft tissue changes following extraction vs. nonextraction orthodontic fixed appliance treatment: a systematic review and meta-analysis

The aim of this systematic review was to assess the effect of systematic extraction protocols during orthodontic fixed appliance treatment on the soft tissue profile of human patients. Nine databases were searched until December 2016 for controlled clinical studies including premolar extraction or nonextraction treatment. After elimination of duplicate studies, data extraction, and risk-of-bias assessment according to the Cochrane guidelines, random-effects meta-analyses of mean differences (MD) or standardized mean differences (SMD) and their 95% CIs were performed, followed by subgroup, meta-regression, and sensitivity analyses. Extraction treatment was associated with increased lower lip retraction (24 studies; 1,456 patients; MD = 1.96 mm), upper lip retraction (21 studies; 1,149 patients; MD = 1.26 mm), nasolabial angle (21 studies; 1,089 patients; MD = 4.21°), soft-tissue profile convexity (six studies; 408 patients; MD = 1.24°), and profile pleasantness (three studies; 249 patients; SMD = 0.41). Patient age, extraction protocol, and amount of upper incisor retraction during treatment were significantly associated with the observed extraction effects, while the quality of evidence was very low in all cases due to risk of bias, baseline confounding, inconsistency, and imprecision. Although tooth extractions seem to affect patient profile, existing studies are heterogenous and no consistent predictions of profile response can be made.

Are there differences in treatment effects between labial and lingual fixed orthodontic appliances? A systematic review and meta-analysis

Background

An evaluation is made of possible differences in treatment effects between labial and lingual fixed appliances.

Methods

A comprehensive search was made of the PubMed-Medline, Cochrane Library and LILACS databases, with an additional manual search covering the period up until April 2017. There were no restrictions in terms of year of publication or language. Agreement between the authors was quantified by the Cohen kappa statistic. A random-effect model was applied to calculate weighted mean differences with 95% confidence intervals.

Results

A total of 249 patients corresponding to four eligible studies were included in the systematic review. Among the six angles and distances entered in the meta-analysis, a tendency was observed in lingual appliances to increase the interincisal angle (95% CI −0.80-8.99; p = 0.101) and reduce the angle between the major axis of upper central incisor and the sellar-nasion plane - though statistical significance was not reached (95% CI −5.75-0.32; p = 0.079).

Conclusion

The results obtained indicate that treatment with lingual appliances favors incisor tipping by exerting lingual crown torque, but there are no differences in cephalometric values between labial and lingual fixed appliances. Because of the small number of included studies, the results of this meta-analysis should be interpreted with caution. Future research should focus on the generation of a consensus document allowing selection of the type of orthodontic approach not only conditioned to the esthetic requirements of the patient but also considering the characteristics of the malocclusion. On the other hand, standardized international guidelines are lacking; the measurements of angles and distances therefore have to be unified with a view to future investigations.

Outcomes of comprehensive fixed appliance orthodontic treatment: A systematic review with meta-analysis and methodological overview

Objective

The aim of this systematic review was to assess the occlusal outcome and duration of fixed orthodontic therapy from clinical trials in humans with the Objective Grading System (OGS) proposed by the American Board of Orthodontics.

Methods

Nine databases were searched up to October 2016 for prospective/retrospective clinical trials assessing the outcomes of orthodontic therapy with fixed appliances. After duplicate study selection, data extraction, and risk of bias assessment according to the Cochrane guidelines, random-effects meta-analyses of the mean OGS score and treatment duration were performed and 95% confidence intervals (CIs) were calculated.

Results

A total of 34 relevant clinical trials including 6,207 patients (40% male, 60% female; average age, 18.4 years) were identified. The average OGS score after treatment was 27.9 points (95% CI, 25.3–30.6 points), while the average treatment duration was 24.9 months (95% CI, 24.6–25.1 months). There was no significant association between occlusal outcome and treatment duration, while considerable heterogeneity was identified. In addition, orthodontic treatment involving extraction of four premolars appeared to have an important effect on both outcomes and duration of treatment. Finally, only 10 (39%) of the identified studies matched compared groups by initial malocclusion severity, although meta-epidemiological evidence suggested that matching may have significantly influenced their results.

Conclusions

The findings from this systematic review suggest that the occlusal outcomes of fixed appliance treatment vary considerably, with no significant association between treatment outcomes and duration. Prospective matched clinical studies that use the OGS tool are needed to compare the effectiveness of orthodontic appliances.

Randomized clinical trials in orthodontics are rarely registered a priori and often published late or not at all

A priori registration of randomized clinical trials is crucial to the transparency and credibility of their findings. Aim of this study was to assess the frequency with which registered and completed randomized trials in orthodontics are published. We searched ClinicalTrials.gov and ISRCTN for registered randomized clinical trials in orthodontics that had been completed up to January 2017 and judged the publication status and date of registered trials using a systematic protocol. Statistical analysis included descriptive statistics, chi-square or Fisher exact tests, and Kaplan-Meier survival estimates. From the 266 orthodontic trials registered up to January 2017, 80 trials had been completed and included in the present study. Among these 80 included trials, the majority (76%) were registered retrospectively, while only 33 (41%) were published at the time. The median time from completion to publication was 20.1 months (interquartile range: 9.1 to 31.6 months), while survival analysis indicated that less than 10% of the trials were published after 5 years from their completion. Finally, 22 (28%) of completed trials remain unpublished even after 5 years from their completion. Publication rates of registered randomized trials in orthodontics remained low, even 5 years after their completion date.

Interventions for orthodontically induced white spot lesions: a systematic review and meta-analysis

Background

Although orthodontic white spot lesions (WSLs) are one of the most often and most evident adverse effects of comprehensive fixed appliance treatment, the efficacy of interventions for WSLs has not yet been adequately assessed in an evidence-based manner.

Objective

Aim of this systematic review was to assess the therapeutic and adverse effects of interventions to treat post-orthodontic WSLs from randomized trials in human patients.

Search methods

An unrestricted electronic search of eight databases from inception to May 2016.

Selection criteria

Randomized controlled trials assessing any interventions for post-orthodontic WSLs on human patients.

Data collection and analysis

After duplicate study selection, data extraction, and risk of bias assessment according to the Cochrane guidelines, random-effects meta-analyses of mean differences (MDs), standardized mean differences (SMDs), and odds ratios (ORs), including their 95% confidence intervals (CIs) were performed, followed by subgroup and sensitivity analyses.

Results

A total of 20 unique studies and a total of 942 (42 per cent male and 58% per cent female) patients were included, with an average age of 16.2 years and a mean number of 8.2 WSLs (range 2.2 to 45.4) per patient. These were allocated to adjunct treatment with casein phosphopeptide-stabilized amorphous calcium phosphate creams, external tooth bleaching, low- or high-concentration fluoride films, gels, mouthrinses or varnishes, resin infiltration, miswak chewing sticks, bioactive glass toothpastse, or to no adjunct treatment (i.e. conventional oral hygiene). The monthly use of fluoride varnish was the best supplement to improve WSLs in terms of lesion area (1 trial; MD = -0.80 mm2; 95% CI = -1.10, -0.50 mm2; P < 0.05; high quality) and enamel fluorescence (3 trials; SMD = -0.92; 95% CI = -1.32, -0.52; P < 0.05; high quality), followed by the use of fluoride film. WSL treatment did not provide a considerable improvement in their clinical evaluation (3 trials; OR = 0.97; 95% CI = 0.60, 1.56; P > 0.05; moderate quality), with imprecision due to small sample size being the main limitation of existing evidence.

Conclusions

Based on the existing trials, interventions for post-orthodontic WSLs, mainly fluoride varnish, seem to be effective, but further research is needed to elucidate their clinical relevance.

Registration

PROSPERO (CRD42016037538).

Torque differences due to the material variation of the orthodontic appliance: a finite element study

Background

Torque of the maxillary incisors is crucial to occlusal relationship and esthetics and can be influenced by many factors. The aim of this study was to assess the relative influence of the material of the orthodontic appliance (adhesive, bracket, ligature, and wire) on tooth displacements and developed stresses/strains after torque application.

Methods

A three-dimensional upper right central incisor with its periodontal ligament (PDL) and alveolus was modeled. A 0.018-in. slot discovery® (Dentaurum, Ispringen, Germany) bracket with a rectangular 0.018 x 0.025-in. wire was generated. The orthodontic appliance varied in the material of its components: adhesive (composite resin or resin-modified glass ionomer cement), bracket (titanium, steel, or ceramic), wire (beta-titanium or steel), and ligature (elastomeric or steel). A total of 24 models were generated, and a palatal root torque of 5° was applied. Afterwards, crown and apex displacement, strains in the PDL, and stresses in the bracket were calculated and analyzed.

Results

The labial crown displacement and the palatal root displacement of the tooth were mainly influenced by the material of the wire (up to 150% variation), followed by the material of the bracket (up to 19% variation). The magnitude of strains developed in the PDL was primarily influenced by the material of the wire (up to 127% variation), followed by the material of the bracket (up to 30% variation) and the ligature (up to 13% variation). Finally, stresses developed at the bracket were mainly influenced by the material of the wire (up to 118% variation) and the bracket (up to 59% variation).

Conclusions

The material properties of the orthodontic appliance and all its components should be considered during torque application. However, these in silico results need to be validated in vivo before they can be clinically extrapolated.

Electronic supplementary material

The online version of this article (doi:10.1186/s40510-017-0161-5) contains supplementary material, which is available to authorized users.

Evidence regarding lingual fixed orthodontic appliances' therapeutic and adverse effects is insufficient

Data sourcesMedline, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects, Cochrane Central Register of Controlled Trials, Virtual Health Library and Web of Science were systematically searched up to July 2015 without limitations. Scopus, Google Scholar, ClinicalTrials.gov, the ISRCTN registry as well as reference lists of the trials included and relevant reviews were manually searched.Study selectionRandomised (RCTs) and prospective non-randomised clinical trials (non-RCTs) on human patients that compared therapeutic and adverse effects of lingual and labial appliances were considered. One reviewer initially screened titles and subsequently two reviewers independently screened the selected abstracts and full texts.Data extraction and synthesisThe data were extracted independently by the reviewers. Missing or unclear information, ongoing trials and raw data from split-mouth trials were requested from the authors of the trials. The quality of the included trials and potential bias across studies were assessed using Cochrane's risk of bias tool and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. For parallel trials, mean difference (MD) and the relative risk (RR) were used for continuous (objective speech performance, subjective speech performance, intercanine width, intermolar width and sagittal anchorage loss) and binary outcomes (eating difficulty), respectively. The standardised mean difference (SMD) was chosen to pool, after conversion, the outcome (oral discomfort) that assessed both binary and continuous. Random-effects meta-analyses were conducted, followed by subgroup and sensitivity analyses.ResultsThirteen papers pertaining to 11 clinical trials (three parallel RCTs, one split-mouth RCT and seven parallel prospective non-RCTs) were included with a total of 407 (34% male/66% female) patients. All trials had at least one bias domain at high risk of bias. Compared with labial appliances, lingual appliances were associated with increased overall oral discomfort, increased speech impediment (measured using auditory analysis), worse speech performance assessed by laypersons, increased eating difficulty and decreased intermolar width. On the other hand, lingual appliances were associated with increased intercanine width and significantly decreased anchorage loss of the maxillary first molar during space closure. However, the quality of all analyses included was judged as very low because of the high risk of bias of the included trials, inconsistency and imprecision.ConclusionsBased on existing trials there is insufficient evidence to make robust recommendations for lingual fixed orthodontic appliances regarding their therapeutic or adverse effects, as the quality of evidence was low.