Complications, impacts, and success rates of different approaches to treatment of Class II malocclusion in adolescents: A systematic review and meta-analysis


We aimed to explore the prevalence and nature of complications associated with Class II correctors in adolescents and their impact on the quality of life (QOL), completion of treatment, and success rate.


The review was registered in PROSPERO, and a comprehensive electronic search was performed without language or date restrictions. Randomized and nonrandomized trials, prospective cohort and cross-sectional studies, case series, and qualitative research were included. The Cochrane Collaboration’s risk of bias tool and the Newcastle-Ottawa scale were used to assess the quality of included studies. Data were grouped according to appliances design: removable functional, fixed functional, hybrid functional, headgear, and fixed maxillary molar distalization appliances.


Data from 27 studies were included, of which 11 were deemed eligible for meta-analysis. Overall, 1676 adolescents were included related to fixed functional (n = 682), removable functional (n = 682), hybrid functional (n = 84), headgear (n = 186), and Carriere (n = 42) appliances. The mean number of emergencies was 0.8 (95% confidence interval [CI], 1.1-2.1) and 2 (95% CI, 0.9-3.0) for removable and fixed designs, respectively. However, the rate of discontinuation was 35% (95% CI, 0.28-0.42) and just 1% (95% CI, 0.01-0.1) for removable and fixed designs, respectively. Other QOL dimensions such as eating, sleep, speech, and emotional domains were significantly impaired during treatment with removable functional appliances.


Removable Class II correctors were associated with a high rate of treatment discontinuation, most likely because of the negative impact on QOL and lack of compliance. More complications were observed with fixed designs, although this did not impact the overall success rates. Further prospective studies are needed to explore patient perceptions and cost-effectiveness to inform treatment decisions better.


  • Class II malocclusion can be treated using a wide variety of appliances and techniques.

  • Assessing complications and patient experiences associated with appliance wear is essential.

  • Evaluating success rate can help in choosing the appropriate type and obtaining informed consent.

  • Complications were more prevalent with fixed designs but success rate was significantly higher.

  • Patient experiences while wearing Class II correctors are not fully understood.

Class II malocclusion has a prevalence of approximately 25% among 12-year-olds in the United Kingdom. Affected children are more likely to experience teasing, with resultant psychological harms and distress and negative connotations for self-esteem and the quality of life (QOL) for both child and family. ,

Currently, Class II malocclusion in growing adolescents can be treated using a wide variety of appliances and techniques, including Class II correction appliances and/or fixed multibracket appliance with a combination of selective extraction and/or the use of interarch elastics. Removable, fixed, intramaxillary, and intermaxillary Class II correctors exist. Intramaxillary appliances are routinely fitted to the maxillary first molars aiming to either restrain the forward growth of the maxilla (eg, removable headgear) or to distalize the maxillary molars using fixed devices (eg, pendulum, Carriere, and distal jet). Functional appliances have an intermaxillary design and can be grouped into (1) removable (eg, Twin-block [TB], activator, and prefabricated appliance), (2) hybrid (eg, Dynamax), and (3) fixed. However, the fixed design can be further subclassified into (1) fixed rigid (eg, Herbst, fixed TB, and mandibular protraction appliance), and (2) fixed flexible designs (eg, Forsus fatigue resistance device). The primary difference between fixed and removable Class II correctors is the premium on compliance with removable variants, whereas full-time wear is guaranteed with the fixed design.

There is widespread consensus that these appliances and techniques can successfully correct Class II characteristics, including the reduction of the overjet to within normal limits by producing a combination of dental and skeletal effects. Moreover, there is also evidence of an association with complications and negative impact on oral health–related quality of life (OHRQOL), with successful treatment dependent on patient acceptance and their ability to adapt to the appliance.

It is increasingly accepted that orthodontic research tends to be overly focused on clinician-centered outcomes (eg, cephalometric changes rather than those that matter more to patients). Furthermore, a recent systematic review comparing the effectiveness of fixed and removable functional appliances concluded that there was a lack of data relating to patient experiences and potential complications during Class II treatment and hence emphasized the need for further prospective studies focusing on these outcomes to inform the consent process and treatment decisions better.

Whereas several studies have been carried out to assess the impact of Class II malocclusion on the OHRQOL, , others evaluated the potential role of overjet correction in improving the QOL of affected children. However, there is a little consensus concerning key patient-reported outcomes during Class II treatment. Therefore, this systematic review aimed to assess complications and patient experiences during the wear of Class II correctors and to evaluate their impact on OHRQOL and success rate, in order to evaluate the efficacy and safety of appliances when considering Class II correction.

Material and methods

Protocol and registration

The protocol for this systematic review was registered with PROSPERO ( , CRD42019121628).

Eligibility criteria

The following inclusion and exclusion criteria were applied:

  • 1.

    Population: adolescents (aged <18 years) with a Class II malocclusion.

  • 2.

    Intervention: orthodontic treatment with a Class II correction appliance, including any type of functional appliances (fixed or removable), headgear, maxillary molar distalizing device, or other Class II correctors.

  • 3.

    Comparison: a comparison and/or control group was not essential.

  • 4.

    Outcomes: (1) nature, severity (minor, moderate, severe, or treatment failure) and prevalence of emergencies and/or complications (eg, pain, harms, breakages, and other complications associated with the treatment); (2) patient experiences and impact of appliance wear on OHRQOL; and (3) impact of associated complications and/or OHRQOL domains on patient compliance and discontinuation of treatment (success rate).

  • 5.

    Study design: The following study designs were considered eligible if they incorporated subjective data on complications associated with the Class II treatment and impact on OHRQOL: randomized controlled trials, nonrandomized controlled clinical trials, observational cohort and cross-sectional studies, and prospective case series (minimum sample size of 10 patients). Qualitative studies exploring patients’ views and experiences during Class II treatment were also included. Only data relating to patients’ experiences during Class II correction and treatment discontinuation were extracted, with clinician-centered outcomes omitted from the review.

Studies were excluded if compliance only was measured if treatment was confined to fixed multiple-bracket appliance alone (eg, with Class II elastics) and/or a simple removable appliance, explored the effects of treated and/or untreated malocclusion on OHRQOL, involved the effects on the temporomandibular joint, or involved participants with craniofacial growth syndromes.

Information sources, search strategy, and study selection

The search strategy included terms related to orthodontic complications, experiences, and QOL during Class II correction involving any type of removable or fixed functional appliance, headgear, and other Class II corrector ( Appendix I ). Comprehensive searches, without date restrictions, were conducted using the following electronic databases: MEDLINE (via PubMed and Ovid), Web of Science, Cochrane, and Embase. A gray literature search was also undertaken using Google Scholar and OpenGrey. Hand searching was performed from the reference lists of the full-text articles considered eligible for inclusion and other relevant systematic reviews. Assessments of studies for inclusion in the review were performed independently and in duplicate by 2 authors (M.M.P. and A.J.), and any disagreements were resolved by discussion with a third author (P.S.F.) who was not involved in the original screening. If further information regarding patient experiences or OHRQOL were required, authors were contacted for clarification.

Risk of bias and quality assessment in individual studies

Two authors independently assessed the risk of bias of the included studies (M.M.P. and A.J.), and any disagreements were resolved by further discussion and consensus. Because of diversity in the design of included studies, 2 different tools were used to assess their quality. Randomized controlled trials were assessed using the Cochrane Collaboration’s risk of bias tool. The following 7 domains were considered: sequence generation, allocation concealment, blinding participants, blinding of outcome assessors, incomplete outcome data, selective reporting, and other biases.

An appropriately modified version of the Newcastle-Ottawa scale was used to assess the quality of nonrandomized studies, including the adapted version of the scale suitable for the assessment of cross-sectional studies. This tool comprised 9 domains, which are divided into 3 broad criteria: patient selection, comparability of study groups, and outcome assessment. Studies were awarded stars according to their methodologic quality, with a high-quality study achieving the maximum score of 9 stars. Studies achieving between 6 and 8 stars were considered of moderate quality, whereas a rating of 5 stars or less indicated low quality. Studies at low or unclear risk of bias or medium to high quality were planned for inclusion in any subsequent meta-analysis.

Data items and collection

The following characteristics were recorded: study design, sample size, setting, treatment duration, participant details, and type of treatment and outcomes relevant to experiences during treatment (eg, complications and impact of treatment on OHRQOL). Data were extracted and grouped according to their design as removable functional, fixed functional, hybrid functional, headgear, and fixed maxillary molar distalization appliance. Measurements or outcomes related to morphologic changes during treatment were omitted. Complications and emergencies during treatment were categorized according to their severity as follows: (1) minor: the function of the appliance was not impaired, and repair could be undertaken during the same appointment; (2) moderate: the function was impaired, but emergencies could be resolved at the same appointment at chairside; (3) severe: the function was impaired, and repair require any laboratory input; and (4) treatment failure: complication leading to termination of treatment ( Table I ).

Table I
Classification of potential complications and adverse events associated with Class II correction using fixed or removable appliances
Severity of incidence Removable appliance Fixed appliance
  • Loosening or crib fracture, where retention and stability of the appliance was still acceptable

  • Soft tissue irritation owing to rubbing or sharp edges

  • Band and/or crown decementation

  • Soft tissue irritation owing to rubbing or sharp edges

  • Loss of appliance retention and stability, compromising the use of the appliance

  • Detachment, distortion, or loss of the appliance which can be repaired or replaced at the same appointment

  • Fracture of acrylic component that requires laboratory repair

  • Loss of the appliance

  • Component impinging and/or embedded on the mucosal tissue to the degree that removal followed by replacement after healing or refabrication is required

  • Fracture of key components

  • Severe damage and/or harm to the teeth or the mucosal tissue

  • Very poor oral hygiene to the degree that treatment becomes harmful

  • Severe damage and/or harm to the teeth or the mucosal tissue

  • Very poor oral hygiene to the degree that treatment becomes harmful

Summary measures and approach to statistical analysis

Data concerning patient experiences of treatment (eg, number, type, and severity of emergency visits) were expressed as a number or percentage (prevalence) of all treated patients). OHRQOL scores reporting on the same domain were combined to obtain pooled mean proportion values, with standard deviation and/or 95% confidence interval (CI) if applicable. Data from qualitative studies were planned for synthesis if the same outcome was reported in more than 2 studies, followed by the integration of quantitative and qualitative results.

Risk of bias across studies

To identify publication bias, we drew standard and contoured enhanced funnel plots if sufficient numbers of studies were identified (>10 studies).

Additional analysis

A meta-analysis was planned for studies with low and/or unclear risk of bias and moderate- to high-quality studies, using similar design and reporting the same outcome, after grouping data according to Class II corrector classification, to estimate the overall impact on the rate and/or the number of emergencies, treatment discontinuation, and OHRQOL (patient experiences). However, owing to the proportional nature of these outcomes and the use of single-arm data, a random-effects specific meta-analysis was undertaken using bespoke open-source software (OpenMeta[Analyst], Brown University of Public Health, RI). Results were to be presented as forest plots with weighted values and 95% CIs, with a P value of <0.05 considered statistically significant. The I 2 statistic was applied to quantify heterogeneity among studies, with an I 2 statistic value of up to 35% indicating low, 35%-70% moderate, and 70%-100% high heterogeneity. However, it should be noted that this test reflected the variation in the sample size and the proportional nature of the outcome (eg, frequency of reported complications) rather than the variability of the comparable outcomes in which there was a control group.


Study selection and characteristics of included studies

A total number of 461 studies were initially identified, with a further 19 articles obtained through other sources, of which 51 full-text articles were evaluated for inclusion ( Fig 1 ). After evaluation, 22 full-text articles were excluded ( Appendix II ), whereas 29 articles met the selection criteria; however, 2 articles reported on data from the same study, , with an additional 2 articles related to the same cohort study. , Thus, 27 unique datasets were eventually included in the qualitative and quantitative synthesis. , , , Of these datasets, 9 were randomized controlled trials, , , , , , , , , 6 were controlled clinical trials, , , , 1 was a case series, 8 were prospective observational studies, , , , , , , , and 3 were qualitative studies. The vast majority of included studies were carried out in a university or hospital setting apart from 4 studies, which were undertaken in private practices. , , , The appliances used varied significantly, with some studies evaluating a single treatment and others comparing 2 or 3 different types of Class II correction appliances ( Appendix III ; Table II ).

Fig 1
Preferred Reporting Items for Systematic Reviews and Meta-Analyses flow chart of article identification and selection. RCT , randomized controlled trial; CCT , controlled clinical trial.

Table II
Baseline characteristics and outcome measurements of the included studies
Study and/or design Appliance and/or participants and/or duration and/or setting Outcomes and/or measurement method Prevalence and/or number and/or severity of complications OHRQOL and/or patient experiences Rate of discontinuation
Alzoubi et al
TB (n = 49): 20 M, 29 F
Age range: 10-16 y
Location: University of Malta, Malta
OHRQOL and patients experience
OHIP-14 questionnaire (at baseline, 6-wk, 12-wk, 6-mo)
(n = 29)
Speech problems: −1.3 ± 1.3
Pain: −0.8 ± 0.9
Eating problems: −1.1 ± 1.1
Embarrassment: −1 ± 1.1
Works and jobs: −0.6 ± 0.9
Baysal and Uysal
Herbst (n = 23): 9 M, 11 F
Duration: 15.8 ± 6 mo
TB (n = 24): 9 M, 11 F
Duration: 16.2 ± 7.5 mo
Mean age: 12.9 ± 1.1 y
Location: Erciyes University, Turkey
Number of complications
Clinical notes
TB (n = 20): 0.4 ± 0.6
Herbst (n = 20): 0.95 ± 1.1
TB (n = 24): 4 (16.7%)
Herbst (n = 23): 3 (13%)
Bowman et al
FFRD (n = 70): 40 F, 30 M
Duration: ≥2 mo
Mean age: 14.5 ± 1.5 y
Location: University of Buffalo and private clinic, United States
OHRQOL, patients experiences, and prevalence and/or number of complications
Modified Smiles Better questionnaire and clinical notes
(n = 67)
25 (37.3%)
(n = 67)
Look scary: 5 (7.1%)
Speech problems: 2 (3%)
Eating problems: 5 (7.5%)
Sleep problems: 8 (12%)
Teasing: 0 (0%)
Pain: 5 (7.5%)
Schoolwork: 0 (0%)
Carter et al
Removable functional (n = 6): 5 F, 1 M
Age range: 11-14 y
Location: Newcastle Dental Hospital, United Kingdom
Impacts on eating
Semistructured interviews
(n = 6)
Eating problems: limitation of food choices, distress eating with the appliance, longer time to eat, being messy, embarrassment, difficulties of chewing, alteration of taste, and lack of adaptation
Čirgić et al
Myobrace (n = 9): 5 F, 4 M
Duration: 6 mo
Activator (n = 12): 6 F, 6 M
Duration: 6 mo
Mean age: 13.2 ± 1.25 y
Location: University of Gothenburg, Sweden
OHRQOL and patients experience
Semistructured interviews
(n = 21)
Pain and discomfort: painful at the start, difficulty keeping the appliance in the mouth
Teasing and being bullied and embarrassment
Čirgić et al ,
Activator (n = 40): 16 F, 24 M
Myobrace (n = 57): 28 F, 29 M
Mean age: 10.3 ± 1.6 y
Location: 12 dental practices, Sweden
Treatment discontinuation and patients experiences
Clinical notes and customized questionnaire (13-item)
Activator (n = 20); Myobrace (n = 24)
Falling out during sleep: Activator: 6 (30%), Myobrace: 17 (70%)
Sleep problems: Activator: 3 (17%), Myobrace: 11 (45%)
Pain: Activator: 7 (33%), Myobrace: 14 (60%)
Forget to wear: Activator: 6 (28%), Myobrace: 12 (50%)
Social discomfort: Activator: 4 (18%), Myobrace: 3 (12%)
Activator (n = 40): 21 (53%)
Myobrace (n = 57): 40 (70%)
El-Huni et al
TB (n = 22): 7 F, 15 M
Duration: ≥3 mo
Mean age: 12.5 y
Location: Royal London Hospital, United Kingdom
OHRQOL and patients experiences
Semistructured interview
Physical impairment: discomfort and difficulty to speak and eat
Psychologic impairment: a history of teasing or receiving negative comments while wearing the appliance
Recall issues: forgetfulness to wear the appliance and follow instructions
Daily activities: interference with social and educational activities
Adaptability: initial negative impact followed by adaptation
Elkordy et al
FFRD (n = 16 F)
Duration: 5 ± 1.5 mo
Age range: 11-14 y
Location: Cairo University, Egypt
OHRQOL and patients experience, prevalence and/or severity of complications
Clinical notes and customized questionnaire
Mild (swelling of cheeks, gum bleeding): 6 (37.5%)
Moderate (separation of parts): 4 (25%)
Severe (breakages): 3 (19%)
Noticeability: 9 (56.5%)
Speech problems: 1 (6.5%)
Eating problems: 7 (44%)
Sleep problems: 4 (25.5%)
OH problems: 0 (0%)
Pain: 7 (43.5%)
0 (0%)
Feldmann et al
HG (n = 30): 15 F, 15 M
Mean age: 14 ± 1.7 y
Location: Private clinic, Sweden
Patient experiences (pain, discomfort, and jaw function)
Three customized questionnaires
At 1-d: median (IQR)
Pain-incisors: 1 (0-3)
Pain-molars: 0.8 (0-3.4)
Jaw function limitation: low to moderate
At 6-wk: median (IQR)
Pain-incisors: 0 (0-2)
Pain-molars: 0 (0-2)
Gandhi et al
FFRD (n = 12)
MPA (n = 12)
Duration: ≥2 mo
Mean age: 14.5 ± 1.5 y
Location: Institute of Dentistry, India
OHRQOL and patients experiences
Modified Smiles Better questionnaire (at 1-d, 7-d, 14-d, and 30-d)
Speech problems: FFRD: 4.5 (37.5%), MPA: 7.5 (62.5%)
Eating problems: FFRD: 6 (50%), MPA: 7.5 (62.5%)
Sleep problems: FFRD: 0 (0%), MPA: 0 (0%)
Teasing: FFRD: 4.5 (37.5%), MPA: 12 (100%)
Pain-teeth: FFRD: 6 (50%), MPA: 1.5 (12.5%)
Pain-jaw: FFRD: 1.5 (12.5%), MPA: 1.5 (12.5)
Hägg et al
Banded-Herbst (n = 14): 6 F, 8 M
Duration: 6.4 ± 0.7 mo
Casted-Herbst (n = 14): 8 F, 6 M, Duration: 7.1 ± 0.8 mo
Mean age 13 ± 1 y
Location: University of Hong Kong
Number and/or severity of complications
Clinical notes
Banded-Herbst and Casted-Herbst-H (n = 24)
Moderate (dislodged): 1.8 ± 2.4
Severe (fractured): 1.7 ± 2.3
0 (0%)
Hamilton et al
Carriere (n = 42): 26 F, 15 M, 1 unknown
Age range: 11-17 y
Mean age: 13.9 ± 1.3 y
Location: University of Buffalo and 2 private clinics, United States
OHRQOL and patient experiences
Modified Smiles Better questionnaire
Speech problems: 1 (2.5%)
Eating problems: 4 (10%)
Sleep problems: 2 (5%)
Appearance: 3 (7.5%)
Teasing: 1 (2.5%)
Teeth pain: 15 (36.5%)
Jaws pain: 9 (22%)
Hedlund and Feldmann
Activator (n = 85): 33 F, 52 M
Duration: 25.8 ± 12.7 mo
Mean age: 10.9 ± 1.4 y
Location: Public Dental Service, Sweden
Treatment discontinuation, prevalence and/or number of complications, OHRQOL and patient experiences
Clinical notes and customized questionnaire
(n = 85)
0.53 ± 0.76
(n = 38) median (IQR)
Pain and/or discomfort: 42 (22-66)
Sleep problems: 46 (10-59)
Soreness: 26 (11-43)
Mood: 6 (20-18)
Teasing: 1 (0-5)
(n = 35)
14 (41.2%)
Heinig and Göz
Case series
FFRD (n = 13): 5 F, 8 M
Duration: 4 mo
Mean age: 14.2 y
Location: University of Tübingen, Germany
OHRQOL and patient experience Eating problems: 1 (8%)
Speech problems: 1 (8%)
Pain-teeth: 0 (0%)
Pain-jaws: 0 (0%)
Mouth opening: 5 (38%)
Teeth cleaning: 6 (46%)
Sleep problems: 0 (0%)
Appearance: 9 (69%)
Idris et al
T4K (n = 26): 12 F, 14 M
Activator (n = 28): 14 F, 14 M
Mean age: 10.5 y
Location: Hama University, Syria
OHRQOL and patient experiences
Sergl et al questionnaire (at 7-d, 14-d, 3-mo, and 6-mo)
(mean value)
Pain: Activator: (1.2), T4K: (1.2)
Pressure: Activator: (1.3), T4K: (1.5)
Teeth sensitivity: Activator: (1.7), T4K: (2.3)
Speech problems: Activator: (1.4), T4K: (3.2)
Lack of confidence: Activator: (1.3), T4K: (1.8)
Johnson et al
Bionator (n = 79): 30 F, 49 M
HG (n = 89): 37 F, 52 M
Duration: ≤24 mo
Mean age: 9.5 y
Location: University of Florida, United States of America
OHRQOL and patient experiences
Customized questionnaire (28-item)
Pain: Bionator: 43 (54%), HG: 62 (70%)
Eating problems: Bionator: 9 (11%), HG: 22 (25%)
Speech problems: Bionator: 65 (82%), HG: 48 (54%)
Chewing problems: Bionator: 25 (31%), HG: 37 (41%)
Embarrassment: Bionator: 29 (37%), HG: 29 (33%)
Bionator: 30 (38%)
HG: 45 (50%)
Kadkhoda et al
TB (n = 67)
HG (n = 67)
Duration: ≥3 mo
Mean age: 12.5 ± 1.3 y
Location: Tehran University, Iran
OHRQOL and patient experiences
CPQ (11-14) at 3-mo
Pain: TB: (0.4 ± 0.8), HG: (0.6 ± 0.9)
Bad breath: TB: (1.3 ± 1.1), HG: (1.2 ± 1)
Speech problems: TB: (1.5 ± 1.3), HG (0.6 ± 1.1)
Sleep problems: TB: (0.8 ± 1.1), HG: (1.1 ± 1.3)
Teasing: TB: (0.6 ± 1.1), HG: (0.4 ± 0.8)
Upset: TB: (1.2 ± 1.2), HG: (1.0 ± 1.2)
Latkauskiene et al
Crowned-Herbst (n = 180)
Duration: 12 mo
Gender: not clear
Location: private clinic, Lithuania
Treatment discontinuation, prevalence and/or number and/or severity of complications, OHRQOL, and patient experiences
Clinical notes and customized questionnaire (at 6-mo of appliance removal)
(n = 175)
Prevalence: 48 (27.4%)
Minor (loosing crown, bending rods): 27 (15.4%)
Moderate (unscrewing screw, damage attachment): 19 (10.9%)
Severe (fractures): 2 (1.5%)
(n = 87)
Function problems: 0 (0%)
Discomfort: 16 (14%)
Noticeability: 17 (19.5%)
(n = 180)
5 (2.8%)
Lee et al
TB (n = 31): 17 F, 14 M
Dynamax (n = 31): 17 F, 14 M
Duration: 9 mo
Age range: 10.6-14.7 y
Location: Royal London Hospital, United Kingdom
Treatment discontinuation, prevalence and/or number and/or severity of complications
Clinical notes
TB (n = 28): minor (Adams clasp breakages), 10 (35%)
Dynamax (n = 28): severe (vertical components breakages), 15.5 (55%)
TB (n = 31): 3 (10%)
Dynamax (n = 31): 3 (10%)
Lena et al
FFRD (n = 43)
MPA (n = 42)
TB (n = 39)
Duration: 6 mo
Mean age: 13.3 y
Location: Ege University, Turkey
OHRQOL and patient experiences, prevalence of complications
Customized questionnaire (31-item at 6-mo)
TB: 27 (69.3%)
FFRD: 35 (81.4%)
MPA: 41 (97.6%)
Appearance: TB: 23 (59%), FFRD: 27 (62.8%), MPA: 41 (97.6%)
Eating problems: TB: 7 (18%), FFRD: 32 (74.4%), MPA: 33 (78.6%)
Speech problems: TB: 31 (79.6%), FFRD: 15 (34.9%), MPA: 23 (54.7%)
Sleep problems: TB: 24 (61.6%), FFRD: 9 (21%), MPA: 27 (64.3%)
Schoolwork: TB: 15 (38.5%), FFRD: 4 (9.3%), MPA: 14 (33.3%)
Pain-teeth: TB: 24 (61.6%), FFRD 29 (67.4%), MPA: 31 (73.9%)
Pain-jaw: TB: 20 (51.3%), FFRD 26 (60.5%), MPA: 29 (63.5%)
Opening limitation: TB: 26 (66.7%), FFRD: 30 (69.7%), MPA: 31 (73.9%)
OH: TB: 18 (46.1%), FFRD: 24 (55.8%), MPA: 29 (69%)
Moro et al
Crowned-Herbst (n = 21): 6 F, 16 M
Acrylic-Herbst (n = 21): 10 F, 11 M
Duration: 12 mo
Mean age: 11.3-12.3 y
Location: Bauru Dental School and private clinic, Brazil
Prevalence and/or number and/or severity of complications
Clinical notes
Prevalence: Crowned-Herbst: 14 (66.7%), Acrylic-Herbst: 18 (85.7%)
Number: Crowned-Herbst: 24 (1.1 ± 1), Acrylic-Herbst: 53 (2.5 ± 1.8)
Minor (eg, lesions in soft tissue and crown debond): Crowned-Herbst: 15 (62.5%), Acrylic-Herbst: 8 (15%)
Moderate (eg, screw loosening and rod distortion): Crowned-Herbst: 10 (41.6%), Acrylic-Herbst: 27 (51%)
Severe (eg, fracture of appliance parts): Crowned-Herbst: 1 (4.2%), Acrylic-Herbst: 18 (34%)
0 (0%)
O’Brien et al
Casted-Herbst (n = 105): 55 F, 50 M
Duration: 5.8 mo
TB (n = 110): 62 F, 48 M
Duration: 11.2 mo
Mean age: 12.5 y
Location: 13 NHS Hospital, United Kingdom
Treatment discontinuation, number of emergencies, OHRQOL and patients experiences
Clinical notes and Smile Better questionnaire at 4-mo
TB (n = 36): 1.6 ± 1.6
Casted-Herbst (n = 60): 4.3 ± 2.9
TB (n = 110): 37 (33.6%)
Casted-Herbst (n = 105): 18 (17%)
Read et al
F-TB (n = 32)
Duration: 5.1 ± 2 mo
Age range: <15 y
Location: University of Manchester, United Kingdom
Treatment discontinuation, number and/or severity of complications
Clinical notes
Severe (replacement of loose blocks and repair fractured bands): 1.7 ± 1.6 2 (6.3%)
Schiöth et al
Casted-Herbst (n = 50)
Duration: 8 mo
Mean age: 14.5-15.5 y
Location: University of GieBen, Germany, and Bern, Switzerland
Treatment discontinuation, prevalence and/or severity of complications
Clinical notes
Prevalence: 29 (58%)
Moderate (loosening splint): 26 (89%)
Severe (telescope and splint breakages): 3 (11%)
0 (0%)
Sergl and Zentner
-Removable functional (n = 14)
-Duration: 6 mo
-Mean age: 12.8 ± 4 y
-Location: University of Mainz, Germany
OHRQOL and patient experience
Customized questionnaire (at 14-d, 3-mo, 6-mo)
(Mean value)
Pain: (1.5)
Teeth sensitivity: (1.5)
Speech problems: (2)
Swallowing problems: (1.7)
Lack of confidence: (1.7)
Thiruvenkatachari et al
TB (n = 32): 16 F, 16 M
Dynamax (n = 32): 16 F, 16 M
Duration: 9 mo
Age range: 10-14 y
Location: University of Manchester, United Kingdom
Treatment discontinuation, prevalence and/or a number and/or severity of complications
Clinical notes
Breakages: TB: 11 (34.4%), Dynamax: 18 (56.3%)
Adverse events: TB: 5 (17%),
Dynamax: 26 (81%)
Complications: TB: 8 (25.7%), Dynamax: 22 (68.7%)
Nature of Dynamax complications (vertical spur escaping, vertical spur embedded in soft tissue LA buried in the mucosa, fractures of vertical spurs, fracture LA, and fracture of the maxillary plate)
TB: 8 (25%)
Dynamax: 21 (65.6%)
Wiechmann et al
WIN-Herbst (n = 35): 23 F, 12 M
Duration: 10.5 mo
Mean age: 16.9 y
Location: private clinic, Germany
Prevalence and/or number and/or severity of complications
Clinical notes
Number of complications: 13
Prevalence: 10 (28.6%)
Mild: 0 (0%)
Moderate (loosening attachments): 7 (20%)
Severe (fracture of l-pin): 5 (14.3%)
(n = 35): 0 (0%)

RCT , randomized controlled trial; M , male; F , female; OHIP , oral health impact profile; FFRD , Forsus Fatigue Resistance Device; OH , oral hygiene; HG , headgear; IQR , interquartile range; CCT , controlled clinical trial; MPA , mandibular protraction appliance; T4K , Trainer 4 Kids appliance; CPQ , child perception questionnaire; F-TB , Fixed Twin-block; LA , lingual arch.

Values are either n (%) or mean ± standard deviation unless specified otherwise.

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Jan 9, 2021 | Posted by in Orthodontics | Comments Off on Complications, impacts, and success rates of different approaches to treatment of Class II malocclusion in adolescents: A systematic review and meta-analysis
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