Extraction vs nonextraction orthodontic treatment: a systematic review and meta-analysis.

OBJECTIVES: To compare four first premolar extraction and nonextraction treatment effects on intra-arch width, profile, treatment duration, occlusal outcomes, smile aesthetics and stability. MATERIALS AND METHODS: An electronic search of the literature to June 2, 2023 was conducted using health science databases, with additional search of gray literature, unpublished material, and hand searching, for studies reporting nonsurgical patients with fixed appliances regarding sixteen sub-outcomes. Data extraction used customized forms, quality assessed with ROBINS-I (Risk Of Bias In Non-randomized Studies-of Interventions) and Cochrane RoB 2 (risk-of-bias) tool. GRADE (Grading of Recommendations Assessment, Development and Evaluation) assessed certainty of evidence. RESULTS: Thirty (29 retrospective studies, 1 randomized controlled trial) studies were included. Random-effect meta-analysis (95% CI) demonstrated maxillary (MD: -2.03 mm; [-2.97, -1.09]; P < .0001) and mandibular inter-first molar width decrease (MD: -2.00 mm; [-2.71, -1.30]; P < .00001) with four first premolar extraction; mandibular intercanine width increase (MD: 0.68 mm; [0.36, 0.99]; P < .0001) and shorter treatment duration (MD: 0.36 years; [0.10, 0.62]; P = .007) in the nonextraction group. Narrative synthesis included three and five studies for upper and lower lip-E plane, respectively. For American Board of Orthodontics Objective Grading System and maxillary/mandibular anterior alignment (Little's irregularity index), each included two studies with inconclusive evidence. There were no eligible studies for UK Peer Assessment Rating (PAR) score. Class I subgroup/sensitivity analyses favored the same results. Prediction interval indicated no significant difference for all outcomes. CONCLUSIONS: Four first premolar extraction results in maxillary and mandibular inter-first molar width decrease and retraction of upper/lower lips. Nonextraction treatment results in mandibular intercanine width increase and shorter treatment duration. There was no significant difference between the two groups regarding maxillary intercanine width, US PAR score, and posttreatment smile esthetics. Further high-quality focused research is recommended.

Non-surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic treatment.

BACKGROUND: Deviation from a normal bite can be defined as malocclusion. Orthodontic treatment takes 20 months on average to correct malocclusion. Accelerating the rate of tooth movement may help to reduce the duration of orthodontic treatment and associated unwanted effects including orthodontically induced inflammatory root resorption (OIIRR), demineralisation and reduced patient motivation and compliance. Several non-surgical adjuncts have been advocated with the aim of accelerating the rate of orthodontic tooth movement (OTM).         OBJECTIVES: To assess the effect of non-surgical adjunctive interventions on the rate of orthodontic tooth movement and the overall duration of treatment. SEARCH METHODS: An information specialist searched five bibliographic databases up to 6 September 2022 and used additional search methods to identify published, unpublished and ongoing studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) of people receiving orthodontic treatment using fixed or removable appliances along with non-surgical adjunctive interventions to accelerate tooth movement. We excluded split-mouth studies and studies that involved people who were treated with orthognathic surgery, or who had cleft lip or palate, or other craniofacial syndromes or deformities. DATA COLLECTION AND ANALYSIS: Two review authors were responsible for study selection, risk of bias assessment and data extraction; they carried out these tasks independently. Disagreements were resolved by discussion amongst the review team to reach consensus.  MAIN RESULTS: We included 23 studies, none of which were rated as low risk of bias overall. We categorised the included studies as testing light vibrational forces or photobiomodulation, the latter including low level laser therapy and light emitting diode. The studies assessed non-surgical interventions added to fixed or removable orthodontic appliances compared to treatment without the adjunct. A total of 1027 participants (children and adults) were recruited with loss to follow-up ranging from 0% to 27% of the original samples.  Certainty of the evidence For all comparisons and outcomes presented below, the certainty of the evidence is low to very low. Light vibrational forces  Eleven studies assessed how applying light vibrational forces (LVF) affected orthodontic tooth movement (OTM). There was no evidence of a difference between the intervention and control groups for duration of orthodontic treatment (MD -0.61 months, 95% confidence interval (CI) -2.44 to 1.22; 2 studies, 77 participants); total number of orthodontic appliance adjustment visits (MD -0.32 visits, 95% CI -1.69 to 1.05; 2 studies, 77 participants); orthodontic tooth movement during the early alignment stage (reduction of lower incisor irregularity (LII)) at 4-6 weeks (MD 0.12 mm, 95% CI -1.77 to 2.01; 3 studies, 144 participants), or 10-16 weeks (MD -0.18 mm, 95% CI -1.20 to 0.83; 4 studies, 175 participants); rate of canine distalisation (MD -0.01 mm/month, 95% CI -0.20 to 0.18; 2 studies, 40 participants); or rate of OTM during en masse space closure (MD 0.10 mm per month, 95% CI -0.08 to 0.29; 2 studies, 81 participants). No evidence of a difference was found between LVF and control groups in rate of OTM when using removable orthodontic aligners. Nor did the studies show evidence of a difference between groups for our secondary outcomes, including patient perception of pain, patient-reported need for analgesics at different stages of treatment and harms or side effects.  Photobiomodulation Ten studies assessed the effect of applying low level laser therapy (LLLT) on rate of OTM. We found that participants in the LLLT group had a statistically significantly shorter length of time for the teeth to align in the early stages of treatment (MD -50 days, 95% CI -58 to -42; 2 studies, 62 participants) and required fewer appointments (-2.3, 95% CI -2.5 to -2.0; 2 studies, 125 participants). There was no evidence of a difference between the LLLT and control groups in OTM when assessed as percentage reduction in LII in the first month of alignment (1.63%, 95% CI -2.60 to 5.86; 2 studies, 56 participants) or in the second month (percentage reduction MD 3.75%, 95% CI -1.74 to 9.24; 2 studies, 56 participants). However, LLLT resulted in an increase in OTM during the space closure stage in the maxillary arch (MD 0.18 mm/month, 95% CI 0.05 to 0.33; 1 study; 65 participants; very low level of certainty) and the mandibular arch (right side MD 0.16 mm/month, 95% CI 0.12 to 0.19; 1 study; 65 participants). In addition, LLLT resulted in an increased  rate of OTM during maxillary canine retraction (MD 0.01 mm/month, 95% CI 0 to 0.02; 1 study, 37 participants). These  findings were not clinically significant. The studies showed no evidence of a difference between groups for our secondary outcomes, including OIIRR, periodontal health and patient perception of pain at early stages of treatment. Two studies assessed the influence of applying light-emitting diode (LED) on OTM. Participants in the LED group required a significantly shorter time to align the mandibular arch compared to the control group (MD -24.50 days, 95% CI -42.45 to -6.55, 1 study, 34 participants). There is no evidence that LED application increased the rate of OTM during maxillary canine retraction (MD 0.01 mm/month, 95% CI 0 to 0.02; P = 0.28; 1 study, 39 participants ). In terms of secondary outcomes, one study assessed patient perception of pain and found no evidence of a difference between groups.   AUTHORS' CONCLUSIONS: The evidence from randomised controlled trials concerning the effectiveness of non-surgical interventions to accelerate orthodontic treatment is of low to very low certainty. It suggests that there is no additional benefit of light vibrational forces or photobiomodulation for reducing the duration of orthodontic treatment. Although there may be a limited benefit from photobiomodulation application for accelerating discrete treatment phases, these results have to be interpreted with caution due to their questionable clinical significance. Further well-designed, rigorous RCTs with longer follow-up periods spanning from start to completion of orthodontic treatment are required to determine whether non-surgical interventions may reduce the duration of orthodontic treatment by a clinically significant amount, with minimal adverse effects.

Retention procedures for stabilising tooth position after treatment with orthodontic braces.

BACKGROUND: Without a phase of retention after successful orthodontic treatment, teeth tend to 'relapse', that is, to return to their initial position. Retention is achieved by fitting fixed or removable retainers to provide stability to the teeth while avoiding damage to teeth and gums. Removable retainers can be worn full- or part-time. Retainers vary in shape, material, and the way they are made. Adjunctive procedures are sometimes used to try to improve retention, for example, reshaping teeth where they contact ('interproximal reduction'), or cutting fibres around teeth ('percision'). This review is an update of one originally published in 2004 and last updated in 2016. OBJECTIVES: To evaluate the effects of different retainers and retention strategies used to stabilise tooth position after orthodontic braces. SEARCH METHODS: An information specialist searched Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase and OpenGrey up to 27 April 2022 and used additional search methods to identify published, unpublished and ongoing studies.  SELECTION CRITERIA: Randomised controlled trials (RCTs) involving children and adults who had retainers fitted or adjunctive procedures undertaken to prevent relapse following orthodontic treatment with braces. We excluded studies with aligners. DATA COLLECTION AND ANALYSIS: Two review authors independently screened eligible studies, assessed risk of bias and extracted data. Outcomes were stability or relapse of tooth position, retainer failure (i.e. broken, detached, worn out, ill-fitting or lost), adverse effects on teeth and gums (i.e. plaque, gingival and bleeding indices), and participant satisfaction. We calculated mean differences (MD) for continuous data, risk ratios (RR) or risk differences (RD) for dichotomous data, and hazard ratios (HR) for survival data, all with 95% confidence intervals (CI). We conducted meta-analyses when similar studies reported outcomes at the same time point; otherwise results were reported as mean ranges. We prioritised reporting of Little's Irregularity Index (crookedness of anterior teeth) to measure relapse, judging the minimum important difference to be 1 mm. MAIN RESULTS: We included 47 studies, with 4377 participants. The studies evaluated: removable versus fixed retainers (8 studies); different types of fixed retainers (22 studies) or bonding materials (3 studies); and different types of removable retainers (16 studies). Four studies evaluated more than one comparison. We judged 28 studies to have high risk of bias, 11 to have low risk, and eight studies as unclear.  We focused on 12-month follow-up.  The evidence is low or very low certainty. Most comparisons and outcomes were evaluated in only one study at high risk of bias, and most studies measured outcomes after less than a year. Removable versus fixed retainers Removable (part-time) versus fixed   One study reported that participants wearing clear plastic retainers part-time in the lower arch had more relapse than participants with multistrand fixed retainers, but the amount was not clinically significant (Little's Irregularity Index (LII) MD 0.92 mm, 95% CI 0.23 to 1.61; 56 participants). Removable retainers were more likely to cause discomfort (RR 12.22; 95% CI 1.69 to 88.52; 57 participants), but were associated with less retainer failure (RR 0.44, 95% CI 0.20 to 0.98; 57 participants) and better periodontal health (Gingival Index (GI) MD -0.34, 95% CI -0.66 to -0.02; 59 participants). Removable (full-time) versus fixed   One study reported that removable clear plastic retainers worn full-time in the lower arch did not provide any clinically significant benefit for tooth stability over fixed retainers (LII MD 0.60 mm, 95% CI 0.17 to 1.03; 84 participants). Participants with clear plastic retainers had better periodontal health (gingival bleeding RR 0.53, 95% CI 0.31 to 0.88; 84 participants), but higher risk of retainer failure (RR 3.42, 95% CI 1.38 to 8.47; 77 participants). The study found no difference between retainers for caries.  Different types of fixed retainers Computer-aided design/computer-aided manufacturing (CAD/CAM) nitinol versus conventional/analogue multistrand One study reported that CAD/CAM nitinol fixed retainers were better for tooth stability, but the difference was not clinically significant (LII MD -0.46 mm, 95% CI -0.72 to -0.21; 66 participants). There was no evidence of a difference between retainers for periodontal health (GI MD 0.00, 95% CI -0.16 to 0.16; 2 studies, 107 participants), or retainer survival (RR 1.29, 95% CI 0.67 to 2.49; 1 study, 41 participants). Fibre-reinforced composite versus conventional multistrand/spiral wire  One study reported that fibre-reinforced composite fixed retainers provided better stability than multistrand retainers, but this was not of a clinically significant amount (LII MD -0.70 mm, 95% CI -1.17 to -0.23; 52 participants). The fibre-reinforced retainers had better patient satisfaction with aesthetics (MD 1.49 cm on a visual analogue scale, 95% CI 0.76 to 2.22; 1 study, 32 participants), and similar retainer survival rates (RR 1.01, 95% CI 0.84 to 1.21; 7 studies; 1337 participants) at 12 months. However, failures occurred earlier (MD -1.48 months, 95% CI -1.88 to -1.08; 2 studies, 103 participants; 24-month follow-up) and more gingival inflammation at six months, though bleeding on probing (BoP) was similar (GI MD 0.59, 95% CI 0.13 to 1.05; BoP MD 0.33, 95% CI -0.13 to 0.79; 1 study, 40 participants). Different types of removable retainers Clear plastic versus Hawley When worn in the lower arch for six months full-time and six months part-time, clear plastic provided similar stability to Hawley retainers (LII MD 0.01 mm, 95% CI -0.65 to 0.67; 1 study, 30 participants). Hawley retainers had lower risk of failure (RR 0.60, 95% CI 0.43 to 0.83; 1 study, 111 participants), but were less comfortable at six months (VAS MD -1.86 cm, 95% CI -2.19 to -1.53; 1 study, 86 participants). Part-time versus full-time wear of Hawley There was no evidence of a difference in stability between part-time and full-time use of Hawley retainers (MD 0.20 mm, 95% CI -0.28 to 0.68; 1 study, 52 participants). AUTHORS' CONCLUSIONS: The evidence is low to very low certainty, so we cannot draw firm conclusions about any one approach to retention over another. More high-quality studies are needed that measure tooth stability over at least two years, and measure how long retainers last, patient satisfaction and negative side effects from wearing retainers, such as tooth decay and gum disease.

ANTECEDENTES: Sin una fase de retención tras un tratamiento de ortodoncia exitoso, los dientes tienden a "recaer", es decir, a volver a su posición inicial. La retención se consigue colocando retenedores fijos o removibles para proporcionar estabilidad a los dientes y evitar al mismo tiempo daños en dientes y encías. Los retenedores removibles pueden llevarse a tiempo completo o parcial. Los retenedores varían en la forma, el material y el modo de fabricación. A veces se utilizan procedimientos complementarios para intentar mejorar la retención, por ejemplo, remodelando los dientes en la zona de contacto ("reducción interproximal") o cortando fibras alrededor de los dientes ("pericisión"). Esta revisión es una actualización de una publicada originalmente en 2004 y actualizada por última vez en 2016. OBJETIVOS: Evaluar los efectos de los diferentes retenedores y estrategias de retención utilizados para estabilizar la posición de los dientes después del tratamiento con aparatos de ortodoncia. MÉTODOS DE BÚSQUEDA: Un documentalista realizó búsquedas en el Registro de ensayos del Grupo Cochrane de Salud oral (Cochrane Oral Health), en CENTRAL, MEDLINE, Embase y OpenGrey hasta el 27 de abril de 2022 y utilizó métodos de búsqueda adicionales para identificar estudios publicados, no publicados y en curso. CRITERIOS DE SELECCIÓN: Ensayos controlados aleatorizados (ECA) con niños y adultos a los que se les colocaron retenedores o se les realizaron procedimientos complementarios para prevenir la recaída tras el tratamiento con aparatos de ortodoncia. Se excluyeron los estudios con alineadores. OBTENCIÓN Y ANÁLISIS DE LOS DATOS: Dos autores de la revisión realizaron de forma independiente la revisión de los estudios elegibles, evaluaron el riesgo de sesgo y extrajeron los datos. Los desenlaces fueron la estabilidad o recaída de la posición dental, el fracaso del retenedor (es decir, roto, desprendido, desgastado, mal ajustado o perdido), los efectos adversos en dientes y encías (es decir, índices de placa, gingivales y de sangrado) y la satisfacción de los participantes. Se calcularon las diferencias de medias (DM) para los datos continuos, las razones de riesgos (RR) o las diferencias de riesgos (DR) para los datos dicotómicos, y los cociente de riesgos instantáneos (CRI) para los datos de supervivencia, todos ellos con intervalos de confianza (IC) del 95%. Se realizaron metanálisis cuando estudios similares informaron desenlaces en el mismo punto temporal; de lo contrario, los resultados se informaron como rangos medios. Se dio prioridad a la notificación del Little's Irregularity Index (torcedura de los dientes anteriores) para medir la recaída, considerando que la diferencia mínima importante era de 1 mm. RESULTADOS PRINCIPALES: Se incluyeron 47 estudios con 4377 participantes. Los estudios evaluaron: retenedores removibles versus fijos (ocho estudios); diferentes tipos de retenedores fijos (22 estudios) o materiales adhesivos (tres estudios); y diferentes tipos de retenedores removibles (16 estudios). Cuatro estudios evaluaron más de una comparación. Se consideró que 28 estudios tenían un alto riesgo de sesgo, 11 un riesgo bajo y en ocho estudios fue incierto. El centro de atención de esta revisión fue el seguimiento a los 12 meses. La evidencia es de certeza baja a muy baja. La mayoría de las comparaciones y los desenlaces se evaluaron en un solo estudio con alto riesgo de sesgo, y la mayoría de los estudios midieron los desenlaces después de menos de un año. Retenedores removibles versus fijos Removible (a tiempo parcial) versus fijo Un estudio informó que los participantes que llevaban retenedores de plástico transparente a tiempo parcial en la arcada inferior presentaron más recaídas que los participantes con retenedores fijos de múltiples barras, pero la cantidad no fue clínicamente significativa (Little's Irregularity Index [IIL] DM 0,92 mm; IC del 95%: 0,23 a 1,61; 56 participantes). Los retenedores removibles tuvieron más probabilidades de causar molestias (RR 12,22; IC del 95%: 1,69 a 88,52; 57 participantes), pero se asociaron con menos fracaso del retenedor (RR 0,44; IC del 95%: 0,20 a 0,98; 57 participantes) y mejor salud periodontal (Gingival Index [IG] DM ­0,34; IC del 95%: ­0,66 a ­0,02; 59 participantes). Removible (a tiempo completo) versus fijo Un estudio informó que los retenedores removibles de plástico transparente utilizados a tiempo completo en la arcada inferior no proporcionaron efectos beneficiosos clínicamente significativos en la estabilidad dental en comparación con los retenedores fijos (LII DM 0,60 mm; IC del 95%: 0,17 a 1,03; 84 participantes). Los participantes con retenedores de plástico transparente tenían mejor salud periodontal (sangrado gingival RR 0,53; IC del 95%: 0,31 a 0,88; 84 participantes), pero mayor riesgo de fracaso del retenedor (RR 3,42; IC del 95%: 1,38 a 8,47; 77 participantes). El estudio no encontró diferencias entre los retenedores en las caries. Diferentes tipos de retenedores fijos De nitinol con diseño asistido por ordenador/fabricación asistida por ordenador (DAO/FAO) versus de múltiples barras convencional/analógico Un estudio informó que los retenedores fijos de nitinol con DAO/FAO fueron mejores para la estabilidad dental, pero la diferencia no fue clínicamente significativa (LII DM ­0,46 mm; IC del 95%: ­0,72 a ­0,21; 66 participantes). No hubo evidencia de una diferencia entre los retenedores en la salud periodontal (GI MD 0,00; IC del 95%: ­0,16 a 0,16; dos estudios, 107 participantes) ni en la supervivencia del retenedor (RR 1,29; IC del 95%: 0,67 a 2,49; un estudio, 41 participantes). Composite reforzado con fibra versus alambre de múltiples barras/en espiral convencional Un estudio informó que los retenedores fijos de composite reforzado con fibra proporcionaron una mayor estabilidad que los retenedores de múltiples barras, pero no fue clínicamente significativa (LII DM ­0,70 mm; IC del 95%: ­1,17 a ­0,23; 52 participantes). Los retenedores reforzados con fibra tuvieron una mejor satisfacción del paciente con respecto a la estética (DM 1,49 cm en una escala visual analógica; IC del 95%: 0,76 a 2,22; un estudio, 32 participantes) y tasas similares de supervivencia del retenedor (RR 1,01, IC del 95%: 0,84 a 1,21; siete estudios; 1337 participantes) a los 12 meses. Sin embargo, los fracasos se produjeron antes (DM ­1,48 meses; IC del 95%: ­1,88 a ­1,08; dos estudios, 103 participantes; seguimiento de 24 meses) y más inflamación gingival a los seis meses, aunque el sangrado al sondaje (SS) fue similar (GI DM 0,59; IC del 95%: 0,13 a 1,05; SS DM 0,33; IC del 95%: ­0,13 a 0,79; un estudio, 40 participantes). Diferentes tipos de retenedores removibles Plástico transparente versus Hawley Cuando se llevó en la arcada inferior durante seis meses a tiempo completo y seis meses a tiempo parcial, el plástico transparente proporcionó una estabilidad similar a los retenedores Hawley (LII DM 0,01 mm; IC del 95%: ­0,65 a 0,67; un estudio, 30 participantes). Los retenedores Hawley tuvieron un menor riesgo de fracaso (RR 0,60; IC del 95%: 0,43 a 0,83; un estudio, 111 participantes), pero resultaron menos cómodos a los seis meses (EVA DM ­1,86 cm; IC del 95%: ­2,19 a ­1,53; un estudio, 86 participantes). Hawley a tiempo parcial versus a tiempo completo No hubo evidencia de una diferencia en la estabilidad entre el uso a tiempo parcial y a tiempo completo de los retenedores Hawley (DM 0,20 mm; IC del 95%: ­0,28 a 0,68; un estudio, 52 participantes). CONCLUSIONES DE LOS AUTORES: La evidencia es de certeza baja a muy baja, por lo que no fue posible establecer conclusiones firmes sobre un método de retención en detrimento de otro. Se necesitan más estudios de alta calidad que midan la estabilidad de los dientes durante al menos dos años, así como la duración de los retenedores, la satisfacción de los pacientes y los efectos secundarios negativos del uso de retenedores, como caries y enfermedades de las encías.

Temporary anchorage devices and the forces and effects on the dentition and surrounding structures during orthodontic treatment: a scoping review.

BACKGROUND: Temporary anchorage devices (TADs) offer the clinician an immediate temporary source of skeletal anchorage for a range of orthodontic interventions. It is important to understand forces involved in using TADs and the effects on the dentition and surrounding structures, to improve clinical outcomes. OBJECTIVE: To examine and qualitatively synthesize literature on the forces involved with the use of TADs and the effects on the dentition and surrounding structures in orthodontic tooth movement, to provide better understanding of the complex interactions and the clinical implications. SEARCH METHODS: Electronic databases searched included: Cochrane Library [including Central Register of Controlled Trials (CENTRAL)], Embase via OVID, Pubmed, and Scopus. Study screening and selection were conducted in duplicate. SELECTION CRITERIA: Studies selected were clinical studies, simulation studies (computer or laboratory-based), or animal studies with no restriction over gender, age, study type (excluding case reports), or setting. Studies focusing on the forces involved with the use of TADs in orthodontic treatment and their effects on the dentition and surrounding structures were included. DATA COLLECTION AND ANALYSIS: A data charting form was piloted and refined. Data charting was performed independently and in duplicate. This consisted of key fields with predetermined options and free text. The extracted data were collated, and a narrative synthesis conducted. RESULTS: The results from 203 included studies were grouped into seven TAD based interventions combining the clinical, simulation, and animal studies. They were: En masse retraction of anterior teeth, intrusion, movement of a single tooth, orthopaedic interventions, distalisation, maxillary expansion and other types. The forces involved with the use of TADs, and their effects on the dentition and surrounding structures, were presented in descriptive and tabular formats. LIMITATIONS: This review restricted study language to English. Formal appraisal of the quality of evidence is not a required feature of scoping reviews, as per the PRISMA-ScR guidelines, however it was evident that a proportion of clinical studies were of high risk of bias and low quality and therefore any proposed changes the reader may consider to their clinical practice should be contextualized in light of this. CONCLUSIONS: Across the seven types of TAD based interventions the effects on the dentition and surrounding structures are described providing a better understanding of the complex interactions. A guide to the level and direction of forces in each type of intervention is provided to aid clinicians in achieving high quality outcomes. IMPLICATIONS: There is a need to validate future FEA simulation studies by comparing to clinical data. It is also recommended that future scoping reviews incorporate a formal critical appraisal of studies to facilitate the translation of the results into clinical practice. Development of a standard set of terms for TADs is recommended to facilitate future research. REGISTRATION: Registration of a scoping review is not possible with PROSPERO. FUNDING: None to declare.

Which anchorage device is the best during retraction of anterior teeth? An overview of systematic reviews.

Objective: To evaluate the available evidence regarding the clinical effectiveness of different types of anchorage devices. Methods: A comprehensive literature search of different electronic databases was conducted for systematic reviews investigating different anchorage methods published up to April 15, 2021. Any ongoing systematic reviews were searched using PROSPERO, and a grey literature search was undertaken using Google Scholar and OpenGrey. No language restriction was applied. Screening, quality assessment, and data extraction were performed independently by two authors. Information was categorized and narratively synthesized for the key findings from moderate- and high-quality reviews. Results: Fourteen systematic reviews were included (11 were of moderate/high quality). Skeletal anchorage with miniscrews was associated with less anchorage loss (and sometimes with anchorage gain). Similarly, skeletal anchorage was more effective in retracting anterior teeth and intruding incisors and molars, resulting in minor vertical skeletal changes and improvements in the soft tissue profile. However, insufficient evidence was obtained for the preference of any anchorage method in terms of the duration of treatment, number of appointments, quality of treatment, patient perception, or adverse effects. The effectiveness of skeletal anchorage can be enhanced when: directly loaded, used in the mandible rather than the maxilla, used buccally rather than palatally, using dual rather than single miniscrews, used for en-masse retraction, and in adults. Conclusions: The level of evidence regarding anchorage effectiveness is moderate. Nevertheless, compared to conventional anchorage, skeletal anchorage can be used with more anchorage preservation. Further high-quality randomized clinical trials are required to confirm these findings.

Clinical effectiveness of clear aligner treatment compared to fixed appliance treatment: an overview of systematic reviews.

OBJECTIVE: To evaluate the available evidence regarding clinical effectiveness of clear aligner treatment (CAT). MATERIALS AND METHODS: A comprehensive literature search was conducted for systematic reviews investigating effectiveness of CAT published up to July 15, 2021. This was accomplished using different electronic databases. No language restriction was applied. Screening, quality assessment, and data extraction were performed by two authors independently. Information was categorized and narratively synthesized for the key findings from moderate and high-quality reviews. RESULTS: A total of 361 potentially eligible reviews were identified. After excluding the non-relevant/low-quality reviews, 18 systematic reviews were included. CAT was found to be effective for mild to moderate malocclusions, and was associated with inferior outcomes when treating severe cases or with achieving specific tooth movements. There were conflicting results regarding treatment duration; however, CAT may be associated with shorter treatment in mild to moderate cases. Relapse was greater with CAT, while periodontal health was better. The risk of root resorption tended to be lower with CAT. Regarding pain, the results were unclear, although CAT was found to be more comfortable and associated with a reduced impact on eating and chewing. CONCLUSIONS: The level of evidence regarding CAT is moderate; hence, further high-quality randomized clinical trials are required. Evidence supports use of aligners as an alternate to fixed appliances in patients with mild-to-moderate malocclusion but not in severe cases. Advancement in technology could enhance the accuracy of CAT in delivering planned outcomes. CLINICAL RELEVANCE: CAT can be used effectively for selected cases with mild to moderate malocclusion. REGISTRATION: PROSPERO registration number: CRD42021246855.

Development of patient information leaflets for fixed, removable, and functional appliances for Arabic-speaking orthodontic patients.

OBJECTIVE: To develop Orthodontic Patient Information Leaflets (PILs) in Arabic. MATERIAL & METHOD: This study included five phases starting with Arabic translation of existing British Orthodontic Society leaflets; initial face validation with three orthodontists; content validation with ten orthodontists; final face validation with ten orthodontists, five postgraduate students, and ten patients; and re-translation to English prior to comparing the new documents with the original PILs to verify that all the necessary information were included. The content validity index (CVI) assessed item level (I-CVI) and scale level (S-CVI). RESULTS: The three Arabic PILs were face validated with inclusion of mini-screws, rapid maxillary expansion, and interproximal reduction. Content validity was perfect with no item I-CVI < 0.80. The S-CVI/Ave for PIL Fixed Appliances = 0.98, PIL Removable Appliances = 0.98 and PIL Functional Appliances = 0.97. In the final face validation, the three leaflets received 100% agreement from all observers for consistency of leaflet format and style, clarity, readability and use of adequate phrases. Finally, the leaflets were re-translated and the information was checked by native English speakers to ensure the completeness of information. There were no discrepancies and face validity was excellent. CONCLUSION: Valid PILs for Arabic-speaking patients undergoing orthodontic treatment with fixed, removable, and functional appliances have been developed.

Orthodontic treatment and root resorption: an overview of systematic reviews.

BACKGROUND: Root resorption can be considered the most unfortunate complication of orthodontic treatment. OBJECTIVE: To evaluate the available evidence regarding orthodontically induced inflammatory root resorption (OIIRR). SEARCH METHODS: A comprehensive literature search was conducted for the systematic reviews investigating OIIRR published up to 24 May 2020. This was accomplished using electronic databases: MEDLINE via OVID, EMBASE, AMED (Allied and Complementary Medicine Database), PubMed, and Web of Science. Any ongoing systematic reviews were searched using Prospero and a grey literature search was undertaken using Google Scholar and OpenGrey (www.opengrey.eu/). No language restriction was applied. SELECTION CRITERIA: Only studies investigating OIIRR were included. DATA COLLECTION AND ANALYSIS: Screening, quality assessment [using the AMSTAR 2 tool (A Measurement Tool to Assess Systematic Reviews)], and data extraction were performed by two authors independently. Information was categorized and narratively synthesized for the key findings from moderate and high-quality reviews. RESULTS: A total of 2033 potentially eligible studies were identified. After excluding the non-relevant studies, 28 systematic reviews were included. Of which, 20 systematic reviews (71.5%) were of moderate and high-quality level of evidence. The incidence and severity of OIIRR increase with the fixed appliance, especially with heavy force, intrusion, torqueing movements, increased treatment duration, and treatment with extractions or with long apical displacement (particularly for maxillary incisors). There was insufficient evidence regarding most other treatment- and patient-related factors on OIIRR. Following all precautionary measures, pausing treatment and regular monitoring benefits patients with OIIRR. CONCLUSIONS AND IMPLICATIONS: There is a limited number of high-quality studies in terms of OIIRR. The influence of fixed appliance on root resorption was noted; however, the cause and effect relationship between OIIRR and orthodontic biomechanics has not been confirmed. Avoiding heavy, continuous forces and a greater amount of apical displacement over a long duration of treatment is recommended. Precautionary measures should be carefully considered when treating patients with a high risk of OIIRR. REGISTRATION: CRD42020166629.

Powered vs manual tooth brushing in patients with fixed orthodontic appliances: A systematic review and meta-analysis.

OBJECTIVE: The objective of this systematic review and meta-analysis was to compare powered and manual toothbrushes for oral hygiene maintenance in orthodontic patients. METHODS: Electronic databases, including MEDLINE, Scopus, Google scholar, PubMed, Web of Science, the Cochrane Oral Health Group's Trials Register, and CENTRAL, were searched without language restrictions. Randomized clinical trials directly comparing manual and powered toothbrushing including patients with fixed orthodontic appliances reporting predefined outcomes with a follow-up period of at least 4 weeks were included. Using predefined data extraction forms, 2 authors independently undertook data extraction with conflict resolution by the third author. Quality assessment was based on the Cochrane Risk of Bias tool, and overall evidence base was assessed using the Grading of Recommendations Assessment, Development and Evaluation system. A random effects meta-analysis combined the treatment effects across studies. RESULTS: Five trials were considered appropriate for inclusion in the meta-analysis with 8 trials excluded. There are slight differences in plaque index reduction of 0.05 (-0.04, 0.13) and 0.11 (-0.10, 0.33) at 4 week and 8 week follow up, respectively, favoring manual toothbrushing, but this was not statistically significant. There are slight differences in gingival index reduction of -0.02 (-0.06, 0.02) and -0.01 (-0.05, 0.02) at 4 week and 8 week follow up, respectively, favoring powered brushing, but again, this was not statistically significant. The overall quality of evidence was very low to moderate for the primary outcomes. CONCLUSIONS: Using manual or powered tooth brushing with fixed orthodontic appliances does not reduce plaque or gingival indexes at 4 weeks and 8 weeks. This conclusion is, however, based on low quality of evidence from few studies. Greater standardization of the methodology used is desirable in future trials to increase our confidence in these findings.

Prevalence and Occlusal Risk Factors for Fractured Incisors among 11-12-Year-Old Children in the Trinidad and Tobago Population.

This cross-sectional survey was carried out to ascertain the prevalence of fractured incisors in 11-12-year-olds. In addition we explored the relationship with overjet, incompetent lips, incisor inclination and to determine if there was any association with ethnicity and gender. All permanent incisors were examined in 672 children comprising 356 females (53.1%) and 315 males (46.9%). The sample comprised 11-12-year-olds in high schools across Trinidad and Tobago. Statistical analysis was undertaken using Chi-square test, independent t-test, and binary logistic regression. The prevalence of fractured incisors was 18.9%. Boys presented with an increased incidence of fractured incisors than girls. 86.3% of dental trauma was untreated. The average overjet of subjects with fractured incisors was 4.2 mm. 18.62% of subjects with fractured incisors had incompetent lips. The most common malocclusion (18.81%) with fractured incisors was class 2 division 1. The Afro-Trinidadian ethnicity had the highest prevalence of fractured incisors (11.0%) when compared to mixed ethnicities, which was statistically significant. Maxillary central incisors were the most commonly injured teeth. Most patients delayed in seeking dental treatment for fractured incisors in our population. Early orthodontic treatment is recommended to help reduce the risk of dental trauma.

The impact of labial fixed appliance orthodontic treatment on patient expectation, experience, and satisfaction: an overview of systematic reviews.

BACKGROUND: Patient perception with fixed appliance orthodontic treatment is important to improve oral health-related quality of life. OBJECTIVE: The main objective of this study was to evaluate the impact of labial fixed appliance orthodontic care on patient perception before, during, and after the treatment. SEARCH METHODS: Relevant systematic reviews investigating patient perception with fixed appliance orthodontic treatment were identified by searching electronic databases: MEDLINE via OVID (1946 to 31 December 2018), EMBASE (1974 to 31 December 2018), AMED (Allied and Complementary Medicine Database; 1985 to November 2018), PubMed (inception to 31 December 2018), Web of Science (1900 to 2018), and PsychINFO (1806 to 31 December 2018). Ongoing systematic reviews were searched using Prospero and a grey literature search was undertaken using Google Scholar and OpenGrey (www.opengrey.eu/). No language restriction was applied. SELECTION CRITERIA: Only studies investigating patient perception of fixed appliance orthodontic treatment were included. DATA COLLECTION AND ANALYSIS: Screening, quality assessment [using the AMSTAR 2 tool (A Measurement Tool to Assess Systematic Reviews)], and data extraction were performed by two authors independently. Information was categorized and narratively synthesized for the key findings. RESULTS: A total of 163 articles investigating patient expectation, experience, and satisfaction with conventional ligation labial fixed orthodontic appliances were obtained. Of these, 152 observational or interventional studies were excluded, resulting in 11 eligible systematic reviews. Two were excluded as earlier reports of a Cochrane review. The quality of the reviews was variable (critically low, low, and moderate). The findings were as follows: aesthetics represents a primary motive for orthodontic treatment; a temporary deterioration in the quality of life occurs during the initial phases of treatment; gender and ethnicity factors do not have an impact on patient perception of treatment; and a positive relationship between orthodontist-patient-parent is important to achieve patient compliance and satisfaction. CONCLUSIONS: There is a lack of high-quality studies in terms of systematic reviews and meta-analyses for assessing patient perception with fixed appliance orthodontic treatment. The aesthetic impact of malocclusion is the main motive for seeking orthodontic treatment. Quality of life reduces during the initial stages of orthodontic treatment but improves in the later stages of treatment. Assessment before, during, and after orthodontic treatment is necessary to comprehensively assess patient perception at all stages of care. TRIAL REGISTRATION: CRD42019122653. CONFLICT OF INTEREST: None to declare.

Effectiveness of miniscrew-supported maxillary incisor intrusion in deep-bite correction: A systematic review and meta-analysis.

OBJECTIVES: To evaluate systematically the effectiveness of miniscrew-supported maxillary incisor intrusion compared with other nonsurgical intrusive mechanics for deep-bite correction. MATERIALS AND METHODS: Unrestricted electronic searches in Embase, Web of Science, MEDLINE, LILACS, and Cochrane's CENTRAL as well as manual searches were conducted up to August 2019. Only randomized clinical trials (RCTs) were included. Study selection, data extraction, and bias assessment were done by two independent reviewers. The Cochrane risk-of-bias tool was used, and the quality of evidence was graded using the GRADE approach. A random-effects meta-analysis of continuous data, with its 95% confidence intervals (CIs), was used. RESULTS: Seven RCTs were included in the quantitative synthesis, and the overall quality of evidence was very low to low. When compared with intrusion arches, miniscrews resulted in a more efficient deep-bite reduction with a standardized mean difference (SMD) of -0.48 (95% CI, -0.89 to -0.07). When miniscrews were used, a statistically significant difference was observed favoring less maxillary molar extrusion (SMD, -0.86; 95% CI, -1.46 to -0.27) and more incisor intrusion as measured from centroid to palatal plane (SMD, -0.95; 95% CI, -1.41 to -0.49). Results also showed a statistically nonsignificant difference regarding the amount of resultant root resorption between miniscrews and intrusion arches. CONCLUSIONS: There is weak evidence indicating efficient deep-bite correction using miniscrews. Root resorption seems to be an associated adverse effect that occurs regardless of the intrusive mechanics used. These conclusions should be viewed with great caution as further well-designed long-term research is recommended.

Variation in bracket slot sizes, ligation methods and prescriptions: UK national survey.

OBJECTIVE: This study designed to investigate the use of fixed bracket slot sizes, ligation method and prescriptions in the UK using an online survey/questionnaire comprised of seven questions. MATERIAL AND METHODS: The questionnaire link along with an explanation of its nature was circulated via the British Orthodontic Society (BOS) to all 978-email addresses of the Consultant Orthodontists Group (COG) and Orthodontic Specialists Group (OSG) (registered on the UK Specialist List for Orthodontics) members inviting them to participate. Two email reminders were sent to increase the response rate. Chi2 analyses determined the statistical differences in the use of bracket slots and prescriptions according to the regions and years of experience. RESULTS: The respondents represented 31.2% of the BOS specialist orthodontic members. Most of the respondents practised in the South of England with experience between 11-30years. The vast majority of the respondents routinely used brackets with the multibracket appliance treatment (MBT) prescription (81.6%) and 0.022-inch slot size (98.7%), which was statistically significantly higher in all geographical regions and experience levels (P<0.001). The majority of the respondents reported either 100% or 90% use of conventional brackets when compared to self-ligating brackets. CONCLUSION: The vast majority of UK specialist orthodontists use conventional ligating MBT prescription brackets with the 0.022-inch slot size. This was mainly because they perceive that this combination provides better treatment outcomes, whilst many respondents also indicated that they were taught and trained using this combination and that there was not enough evidence to support a change in their clinical practice.

Quantification of maxillary dental midline deviation in 2D photographs: Methodology trial.

INTRODUCTION: Discrepancy of the upper dental midline to the facial midline plays an important role in smile aesthetic assessment. This study presents different reference points to quantify the deviation of upper dental midline to the facial midline in 2D frontal photographs. The aim was to find the most accurate, precise, and practical reference points to measure dental midline discrepancy in 2D photographs. METHODOLOGY: A modified headset with a protractor was developed in order to achieve photographs in nine standardised head positions. Six reference points were used to detect the facial midline in the 2D photographs (eyebrows "EB", inner-canthus of the eyes "ICE", alae of the nose "AN", columella "C", nasolabial folds "NLF", and the philtrum "PH"). The deviation of the maxillary dental midline from the facial midline was measured and compared with clinical measurements. STATISTICAL ANALYSIS: Standard deviations (SD), Root Mean Square Error (RMSE), Method of Moments' Estimator (MME), 2-way repeated measures ANOVA, and multi-level linear model were used to estimate the true errors. RESULTS: The different reference points responded significantly differently to changes in head position and all showed measurement errors, which increased with greater head rotation. Alae of the nose showed the least measurement error and the greatest precision in all head positions. CONCLUSION: The alae of the nose are the recommended reference points to identify the facial midline in order to quantify dental midline deviation from frontal photographs.

Does anchorage loss differ with 0.018-inch and 0.022-inch slot bracket systems?

OBJECTIVES: To compare maxillary first molar anchorage loss between 0.018-inch and 0.022-inch slot fixed appliance systems. MATERIALS AND METHODS: Patients requiring bilateral maxillary premolar extractions (n = 74) within a randomized clinical trial comparing the effectiveness of 0.018-inch and 0.022-inch slot MBT bracket systems (3M-Unitek, Monrovia, Calif) were included. Three-dimensional pre- and posttreatment digital models were landmarked and measured (R700 scanner and OrthoAnalyzer software, 3Shape, Copenhagen, Denmark). Anteroposterior position of the first molars was measured using the third medial rugae point as a reference. Anchorage loss (AL) represented the subtraction of the posttreatment distance from the pretreatment distance for both anchorage loss right (ALR) and left (ALL) sides. The values were then compared using a two-way analysis of variance. RESULTS: There were 41 and 33 cases for the 0.018-inch and 0.022-inch bracket slot systems, respectively. The baseline characteristics were similar between groups, except for the presence or absence of anchorage devices (P = .050). For the total sample: 0.018-inch ALR = 3.86 mm, ALL = 3.30 mm and 0.022-inch ALR = 3.73 mm, ALL = 3.47 mm (P = .970). There was also no significant difference between the 0.018-inch and 0.022-inch groups when subjects with anchorage devices were excluded (P = .383). CONCLUSIONS: Bracket slot size does not influence maxillary molar anchorage loss during orthodontic treatment.

Adhesive precoated bracket systems and operator coated bracket systems: Is there any difference? A systematic review and meta-analysis.

OBJECTIVES: To investigate whether adhesive precoated brackets (APC) are more efficient than operator-coated brackets (OPC) regarding failure rate, bonding time, patient experience, gingival health, plaque accumulation, and white spot lesion formation. MATERIALS AND METHODS: Five online databases: Cochrane Central Register of Controlled Trials (CENTRAL), Scopus, PubMed, MEDLINE, and Web of Science were searched for potential eligible randomized controlled trials (RCTs). A Google Scholar and gray literature search was undertaken. References of included studies were screened for potential eligible studies. Results were collated from each database and modified Cochrane data extraction forms were completed. Quality assessment was performed using Cochrane RoB 2.0 tool for RCTs. RESULTS: Five studies met the inclusion criteria. All reported failure rates using metal brackets for both APC and OPC systems except one that compared clear APC to clear OPC. Three studies reported bonding time differences between the bracket systems. A quantitative synthesis of four studies reporting failure and three reporting bonding time was undertaken. Random effect meta-analysis determined there were no statistically significant differences in bond failures between bracket systems with an odds ratio of 0.890 (P = .808). Bonding time showed a statistically significant (P = .01) but not clinically significant shorter bonding time with OPC. There was insufficient evidence to assess plaque accumulation, gingival health, and either patient or operator experience. CONCLUSIONS: There is no superiority of either bracket system regarding failure rate. OPC are statistically significantly superior over APC in bonding time although this is most likely not clinically significant.

A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 1-duration of treatment.

OBJECTIVE: To compare treatment duration between 0.018-inch and 0.022-inch slot systems and determine factors influencing treatment duration. SUBJECTS AND METHODS: Eligible participants aged 12 years or over were allocated to the 0.018-inch or 0.022-inch slot MBT appliance (3M-Unitek, Monrovia, California, USA) using block randomization in groups of 10. Outcome measures included duration of: 1. overall treatment, 2. levelling and alignment, 3. working and finishing, and 4. appointment numbers and other treatment-related factors. Parametric tests (independent samples t-test) and non-parametric tests (chi-square with Fisher's exact tests and Mann-Whitney U-test) assessed differences between groups. A multiple linear regression analysis identified factors influencing treatment duration (P < 0.05). RESULTS: Of the 187 participants randomized (1:1 ratio), 34 withdrew or were excluded (protocol deviations or poor cooperation). There were 77 patients in the 0.018-inch slot group and 76 patients in the 0.022-inch slot group (overall mean age: 19.1 years). Baseline characteristics were similar between groups (P > 0.05). The mean duration of treatment for the 0.018-inch and 0.022-inch slot groups was 29.3 and 31.2 months, respectively. There were no statistically significant differences between the two treatment groups in terms of treatment duration, duration of the key stages of treatment, and number of appointments (P > 0.05). The regression analysis revealed 33.0 per cent of variance in treatment duration was explained by age at bonding, Class II division 2 malocclusion, number of failed appointments, number of emergency appointments, and transfer to another clinician. There were no adverse events. LIMITATIONS: It was impossible to blind clinicians or patients to allocation and oral hygiene and periodontal outcomes were not assessed. CONCLUSIONS: There was no statistically or clinically significant difference in treatment duration between 0.018-inch and 0.022-inch slot bracket systems. Increasing patient age, Class II division 2 malocclusion, number of failed and emergency appointments, and multi-operator treatment all increase orthodontic treatment duration. REGISTRATION: The trial was registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338. PROTOCOL: The protocol was published at DOI: 10.1186/1745-6215-15-389.

A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 3-biological side-effects of treatment.

OBJECTIVE: To compare orthodontically induced inflammatory root resorption (OIIRR) and patient perception of pain during orthodontic treatment between 0.018-inch and 0.022-inch slot bracket systems. SUBJECTS AND METHODS: Eligible participants aged 12 years or above were allocated to treatment with the 0.018-inch or 0.022-inch slot MBT appliance (3M Unitek, Monrovia, California, USA) using block randomization in groups of 10. OIIRR was assessed radiographically using standardized periapical radiographs before and after 9 months from the start of treatment. Patient perception of pain was assessed using a validated patient questionnaire at 6 months from the start of treatment. Parametric tests (t-test) and non-parametric tests (chi-square with Fisher's exact tests and Kruskal-Wallis test) assessed differences between the groups (P < 0.05). The correlation between severity of OIIRR and abnormal root morphology, history of dental trauma, and pain during treatment was assessed. RESULTS: Of the 187 participants randomized (1:1 ratio), 34 withdrew or were excluded (protocol deviations or poor cooperation). There were 77 patients in the 0.018-inch slot group and 76 patients in the 0.022-inch slot group (overall mean age: 19.1 years). Baseline characteristics were similar between groups (P > 0.05). There was no significant difference in the severity of the OIIRR nor patient perception of pain between the two study groups (P = 0.115 and P = 0.08 respectively). The correlation between the severity of OIIRR and abnormal root morphology or history of dental trauma was not statistically significant (P = 0.086 and P = 0.313). Moreover, there was no significant correlation between the severity of OIIRR and pain during treatment (R = 0.045, P = 0.617). LIMITATIONS: It was impossible to blind clinicians or patients to allocation, and oral hygiene and periodontal outcomes were not assessed. CONCLUSIONS: The effect of bracket slot size on the severity of OIIRR and patient perception of pain are not significant. TRIAL REGISTRATION: The trial was registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338.

A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 2-quality of treatment.

OBJECTIVE: To compare the quality of orthodontic treatment between 0.018-inch and 0.022-inch slot bracket systems. SUBJECTS AND METHODS: Eligible participants aged 12 years or over were allocated to the 0.018-inch or 0.022-inch slot MBT appliance (3M-Unitek, Monrovia, California, USA) using block randomization in groups of 10. Outcome measures included: 1. ABO cast-radiograph evaluation (CR-EVAL), 2. peer assessment rating (PAR) scores, 3. incisor inclination, and 4. patient perception using the Index of Orthodontic Treatment Need aesthetic component (IOTN AC) and three validated questionnaires before, during and after treatment. Parametric tests [independent samples t-test and two-way analysis of variance (ANOVA)] and non-parametric tests (chi-square with Fisher's exact tests and Mann-Whitney U-test) assessed differences between groups (P < 0.05). RESULTS: Of the 187 participants randomized (1:1 ratio), 34 withdrew or were excluded (protocol deviations or poor cooperation). There were 77 patients in the 0.018-inch slot group and 76 patients in the 0.022-inch slot group (overall mean age: 19.1 years). Baseline characteristics were similar between groups (P > 0.05). The mean total ABO CR-EVAL scores were 34.7 and 34.5; mean percentage PAR score reduction 74.1 per cent and 77.1 per cent; mean change for maxillary incisor inclination 2.9 degrees and 1.6 degrees and for mandibular incisor inclination 2.7 degrees and 1.4 degrees for the 0.018-inch and 0.022-inch groups, respectively. Improvement in patient perception of aesthetics after treatment was statistically significant for both groups (P < 0.05). However, there were no statistically significant differences between the two treatment groups for ABO CR-EVAL, percentage PAR score reduction, incisor inclination, and patient perception of treatment (P > 0.05). No adverse events were observed during treatment. LIMITATIONS: It was impossible to blind clinicians or patients to allocation and oral hygiene and periodontal outcomes were not assessed. CONCLUSIONS: There were no statistically or clinically significant differences in the quality of occlusal outcomes, incisor inclination and patient perception of treatment between 0.018-inch and 0.022-inch slot bracket systems. REGISTRATION: The trial was registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338. PROTOCOL: The protocol was published at DOI: 10.1186/1745-6215-15-389.