https://orcid.org/0000-0002-2072-460X
Summary
Skeletally anchored facemask has been proposed to maximize skeletal effects and minimize dental effects in the treatment of Class III malocclusion in growing patients.
To compare the dento-skeletal effects produced by the facemask with or without skeletal anchorage for the treatment of Class III malocclusion in growing patients.
PubMed, Cochrane Library, Scopus, Embase, Web of Science, and OpenGrey were used for the electronic search without language, publication status, and year restrictions. Only RCTs were included. Inclusion criteria were: growing patients (age under 18 years) with Class III malocclusion, with indications for treatment with the facemask. Data were extracted by two independent reviewers. GRADE statement was executed. The mean of differences (MD) and the risk ratio (RR) were used.
Three articles with a total of 123 patients were included. One article was at low risk of bias while two were at high risk of bias. There were no significant differences between the two groups in ANB angle, Wits appraisal, SNB angle, and SN-MP angle. SNA angle was significantly increased in the skeletally anchored facemask (pooled MD = 0.80 favouring skeletal anchorage, 95% CI from 0.29 to 1.31, P = 0.002, I2 = 12 per cent, three studies, GRADE moderate). The U1-SN angle was significantly reduced in the skeletally anchored facemask (pooled MD = −5.91 favouring skeletal anchorage, 95% CI from −7.64 to −4.27, P < 0.00001, I2 = 0 per cent, two studies, GRADE moderate). There were significantly less complications in tooth-anchored facemask (pooled RR = 7.98 favouring dental anchorage, 95 per cent CI from 1.04 to 61.27, P = 0.05, I2 = 0 per cent, two studies, GRADE low).
Few RCTs (three) were included, and two studies were at high risk of bias. There were no long-term RCTs comparing skeletally anchored facemask with dental-anchored facemask. Only Asiatic patients were included in this systematic review.
Skeletally anchored facemask was associated to a greater increase of SNA angle at the end of treatment though clinically not significant. Facemask with skeletal anchorage determined a reduced inclination of maxillary incisors compared to dental-anchored facemask with greater risks of complications.
PROSPERO register (CRD42020221982).
Introduction
Treatment of a Class III malocclusion is one of the most challenging in orthodontic practice. There is large agreement in the literature on the efficacy of orthopaedic treatment of Class III growing patients with a facemask (1–6). The facemask is an extra-oral appliance that has been used for a long time, together with a rigid upper arch appliance, generally a rapid maxillary expander or a double arch in the treatment of a skeletal Class III malocclusion in growing patients (1–3).
The tooth-anchored facemask determines an improvement in the Wits appraisal, an anterior displacement of the A point, a counterclockwise rotation of the maxillary plane and a downward and backward rotation of the mandible which determines the sagittal improvement of Class III skeletal relationships (6–8).
In the short-term the facemask with dental anchorage causes, in addition to skeletal effects, also dental side effects, including the mesialization of the upper molars and incisors, the extrusion of the upper molars with a consequent increase in the lower anterior face height (9–11). However, some mid-term studies have shown that treatment with a rapid maxillary expander and facemask does not determine a significant change in lower face height (8,12).
Recently, the use of skeletally anchored facemask has been introduced to maximize skeletal effects and minimize dental effects, and in clinical circumstances where dental anchorage was difficult (e.g. in multiple congenitally missing teeth or the absence of posterior deciduous teeth) (13–15).
There are two principal locations of skeletal anchorage in the maxilla for facemask protraction: a bilateral insertion of miniplates on the lateral nasal walls (12–19) or at the zygomatic buttresses of the maxilla (9,17,20,21). Other approaches rely on a hybrid expander anchored on two palatal miniscrews to reduce the difficulties in applying miniscrews or miniplates (22,23), or a palatal plate (24).
A systematic review and meta-analysis (25) comparing maxillary protraction with a skeletal anchorage (with a facemask or with intermaxillary elastics) to controls (dental-anchored protraction or untreated controls) revealed that sagittal improvement of skeletal anchored protraction was small and maybe irrelevant.
Recently a systematic review and meta-analysis has been published comparing the skeletal effects of skeletally anchored maxillary protraction versus a dental-anchored maxillary protraction (26). Although this systematic review (26) follows the PRISMA statement and CONSORT checklist for assessing the quality of studies, the inclusion criteria included both prospective and retrospective studies.
A recent network meta-analysis was performed to assess the dento-skeletal effects in skeletal anchored facemask versus a dental-anchored facemask (27). The authors included both RCTs and CCTs, different types of expansion protocols, and both studies which used a facemask and studies which used intermaxillary elastics, leading to a high heterogeneity of results (27).
Systematic reviews of RCTs are considered as the highest quality in the pyramid of evidence (28,29). Systematic reviews and meta-analysis that are present in the literature so far are extremely wide and heterogeneous and include many types of articles, appliances, and types of anchorage, leading to a low reliability of final results. Therefore, the aim of this systematic review and meta-analysis of RCTs was to evaluate the differences between facemask treatment with or without skeletal anchorage in intermaxillary sagittal skeletal effects (difference in ANB or Wits appraisal) and other vertical skeletal effects, patient-reported outcome measures, and complications.
Materials and methods
Eligibility criteria
PICOS process was used to establish the criteria to select studies (Table 1). These criteria are listed in Table 1. Eligible study designs were only RCTs. The included studies should have at least two groups:
Inclusion and exclusion criteria used for study selection (PICOS).
| Element | Contents |
|---|---|
| Participants | Growing patients (age under 18 years) with Class III malocclusion, with indications for treatment with the facemask. The exclusion criteria were: adult, syndromic patients, patients with cleft lip and/or palate, and patients treated with orthognathic surgery. |
| Intervention | Maxillary protraction treatment with a facemask used in conjunction with skeletal anchorage in the maxilla (e.g. miniscrews or miniplates applied in the maxilla). Skeletal anchorage points in the maxilla could be the palate, zygomatic buttresses of the maxilla, lateral nasal walls. Skeletal anchorage could be also composed by one or more miniscrews tied or connected to a dental-anchored appliance (e.g. expanders, a double arch). |
| Comparison | Standard treatment with the facemask used in conjunction with a dental anchorage in the upper arch (e.g. expanders, double arch). |
| Outcome | Primary outcomes: intermaxillary sagittal skeletal effects (difference in ANB or Wits appraisal). Additional outcomes: dentoalveolar effects, sagittal and vertical skeletal effects, patient-reported outcome measures, complications. |
| Study design | Only RCTs (randomized controlled trials). |
| Element | Contents |
|---|---|
| Participants | Growing patients (age under 18 years) with Class III malocclusion, with indications for treatment with the facemask. The exclusion criteria were: adult, syndromic patients, patients with cleft lip and/or palate, and patients treated with orthognathic surgery. |
| Intervention | Maxillary protraction treatment with a facemask used in conjunction with skeletal anchorage in the maxilla (e.g. miniscrews or miniplates applied in the maxilla). Skeletal anchorage points in the maxilla could be the palate, zygomatic buttresses of the maxilla, lateral nasal walls. Skeletal anchorage could be also composed by one or more miniscrews tied or connected to a dental-anchored appliance (e.g. expanders, a double arch). |
| Comparison | Standard treatment with the facemask used in conjunction with a dental anchorage in the upper arch (e.g. expanders, double arch). |
| Outcome | Primary outcomes: intermaxillary sagittal skeletal effects (difference in ANB or Wits appraisal). Additional outcomes: dentoalveolar effects, sagittal and vertical skeletal effects, patient-reported outcome measures, complications. |
| Study design | Only RCTs (randomized controlled trials). |
Inclusion and exclusion criteria used for study selection (PICOS).
| Element | Contents |
|---|---|
| Participants | Growing patients (age under 18 years) with Class III malocclusion, with indications for treatment with the facemask. The exclusion criteria were: adult, syndromic patients, patients with cleft lip and/or palate, and patients treated with orthognathic surgery. |
| Intervention | Maxillary protraction treatment with a facemask used in conjunction with skeletal anchorage in the maxilla (e.g. miniscrews or miniplates applied in the maxilla). Skeletal anchorage points in the maxilla could be the palate, zygomatic buttresses of the maxilla, lateral nasal walls. Skeletal anchorage could be also composed by one or more miniscrews tied or connected to a dental-anchored appliance (e.g. expanders, a double arch). |
| Comparison | Standard treatment with the facemask used in conjunction with a dental anchorage in the upper arch (e.g. expanders, double arch). |
| Outcome | Primary outcomes: intermaxillary sagittal skeletal effects (difference in ANB or Wits appraisal). Additional outcomes: dentoalveolar effects, sagittal and vertical skeletal effects, patient-reported outcome measures, complications. |
| Study design | Only RCTs (randomized controlled trials). |
| Element | Contents |
|---|---|
| Participants | Growing patients (age under 18 years) with Class III malocclusion, with indications for treatment with the facemask. The exclusion criteria were: adult, syndromic patients, patients with cleft lip and/or palate, and patients treated with orthognathic surgery. |
| Intervention | Maxillary protraction treatment with a facemask used in conjunction with skeletal anchorage in the maxilla (e.g. miniscrews or miniplates applied in the maxilla). Skeletal anchorage points in the maxilla could be the palate, zygomatic buttresses of the maxilla, lateral nasal walls. Skeletal anchorage could be also composed by one or more miniscrews tied or connected to a dental-anchored appliance (e.g. expanders, a double arch). |
| Comparison | Standard treatment with the facemask used in conjunction with a dental anchorage in the upper arch (e.g. expanders, double arch). |
| Outcome | Primary outcomes: intermaxillary sagittal skeletal effects (difference in ANB or Wits appraisal). Additional outcomes: dentoalveolar effects, sagittal and vertical skeletal effects, patient-reported outcome measures, complications. |
| Study design | Only RCTs (randomized controlled trials). |
a group consisted of patients with a skeletally anchored device for maxillary protraction (i.e. a facemask with a skeletal anchorage in the maxilla). Skeletal anchorage could be characterized by the application of miniplates or miniscrews in the palate, in zygomatic buttresses of the maxilla, or in lateral nasal walls. Skeletal anchorage could be also composed by one or more miniscrews tied or connected to a tooth-anchored appliance (e.g. maxillary expanders, or a double arch).
a group (Comparison group) consisted of patients with a conventional appliance for maxillary protraction (e.g. a tooth-anchored appliance in the upper arch plus a facemask). Dental anchorage appliance in this group could comprise a maxillary expander or a double arch.
No publication status, language, and year restrictions were applied.
Information sources
An electronic search was performed in six databases, including PubMed (MEDLINE), the Cochrane Library, Scopus, Embase, Web of Science, and OpenGrey. The last access to the databases was performed on January 28 2022. A manual search was also completed in the references of eligibility studies to find further relevant articles. Regarding registers screening, the International Clinical Trials Registry Platform, ClinicalTrials.gov, and the European Clinical Trials Register were included in the Cochrane Library database.
Search strategy
Two query strings using predefined fields and including, if available, a controlled vocabulary (MeSH terms), and DeCS words (child, adolescent, malocclusion, Angle Class III, facemask, face mask, and facial mask) were applied to identify articles within all databases. The references list cited in the selected articles were also checked for any references that could have been missed in the electronic database searches. The search strategy is described in Supplementary Table 1. Two search strings were used with the purpose of providing as many results as possible on the same topic. The two search strings used different specific terms and the results of both strings were then merged into a reference management software (EndNote® X9 Thomson Reuters, Philadelphia, PA) to give rise to a single set of articles. Endnote® software was applied to automatically eliminate duplicate references. After the automatic duplicate’s deletion, a manual screening was completed, to ensure there were no further duplicates.
Selection process
All studies were then independently screened by two authors (SDM and VR) based on title and abstract utilizing the inclusion and exclusion criteria. A first screening was completed to exclude all articles that did not meet the eligibility criteria.
Then, the full-text versions of those studies that fulfilled the inclusion criteria, and of those whose content was not clear based on the data of the title and/or abstract, were obtained.
The same reviewers separately and in double read the full-text of the remaining articles utilizing the eligibility criteria. Any conflict was resolved through discussion and consensus between the two reviewers. A third review author was involved when needed.
Data collection process
Data from the included articles were extracted by two authors (LF and MN) in double and independently and the relevant criteria for the collection of data were determined a priori. Conflicts between the authors were resolved by discussion.
Information of the included articles contained the following: study characteristics (authors, year of publication, and study design), population characteristics (sample size, sex, and age), clinical evaluation characteristics (type of measured outcomes), characteristics of the results (results presented in relation to the study). The authors of the articles were contacted by e-mail if there were absent information and/or missing elements.
Data items
These items were collected from the included articles: study design, sample size, mean age of the patients, sex of the patients, CS, inclusion criteria, exclusion criteria, type of appliance used for anchorage for the facemask, type of anchorage (skeletal/dental), force used for the facemask and inclination of elastics, type of outcome evaluated, duration of treatment, and follow-up.
Study risk of bias assessment
The risk of bias was assessed by two authors (LF and MN) in double and independently. The version 2 of the Cochrane risk-of-bias tool for randomized trials (RoB 2.0) (30) was used to assess the risk of bias of the selected randomized clinical trials. Conflicts between the review authors over the risk of bias were resolved by discussion.
The following biases were examined for each included study: bias arising from the randomization process, bias due to deviations from intended intervention, bias due to missing outcome data, bias in measurement of the outcome, and bias in selection of the reported result.
Each included study was assigned a global ‘low’, ‘high’, or ‘with some concerns’ risk of bias.
Effect measures and synthesis methods
A narrative synthesis of the findings from the included studies was provided. Clinical, methodological, and statistical heterogeneity was evaluated. A quantitative synthesis (meta-analysis) using the Review Manager (RevMan) 5.4.1 software was conducted if the included studies were sufficiently homogeneous. A random effect model was applied. For the aggregation of continuous data, the mean of the differences (MD) between groups was applied. The outcome effect measure for binary outcomes was expressed as risk ratio (RR). Inverse of variance method and a 95 per cent confidence interval (95 per cent CI) were calculated. Heterogeneity was assessed through Chi2 test (in which a P value < 0.1 indicated a statistically significant heterogeneity) and through the inconsistency index (I2). Values above 50 per cent represented substantial heterogeneity. The results of the meta-analysis were reported with a forest plot. If possible, a subgroup analysis by age (children versus adolescents) was planned to carry out. Another subgroup analysis was planned to include only studies with low risk of bias.
Reporting bias assessment
Risk of bias of included studies were described graphically with the risk of bias traffic light plot of RoB2 assessments created using robvis (31). Funnel plot and Egger’s test were planned to investigate the presence of publication bias if at least 10 studies were included in the meta-analysis.
Certainty assessment
The certainty of evidence was assessed by the Grading of Recommendations Assessment, Development and Evaluation (GRADE) (32,33). The following factors were evaluated by two reviewers (LF and MN): RoB (34), inconsistency (heterogeneity) (35), indirectness (36), imprecision (37), and publication bias (38). The quality of evidence was classified into four levels: high, moderate, low, and very low. A ‘Summary of findings’ (SoF) Table was created regarding all outcomes included to give information concerning the quality of evidence from the selected studies.
Results
Study selection
The full PRISMA 2020 statement flowchart is displayed in Supplementary Figure 1.
One thousand eight hundred sixty-eight total articles were recovered on the six electronic databases. After removing duplicates, 766 records remained. Out of 766 articles, 26 were included to be assessed for eligibility after reading the titles and abstracts. After the analysis of the full text, 23 records were excluded. Three more articles retrieved from a search of the citation references (7,39,40) were excluded after reading the full-text. The motivation of their exclusion is reported in Supplementary Table 2.
Many excluded articles were not RCTs. Some articles considered two groups with a skeletally anchored facemask, in others there was no group with a skeletal anchorage.
Corresponding author of one study (41) was contacted by email to confirm that a facemask was used in all patients included in the study.
Three articles were finally included in this systematic review and meta-analysis (41–43).
Study characteristics
Type of study and location
Characteristics of included articles are presented in Table 2. The three included studies [Ge et al. (42); Seiryu et al. (43); Liang et al. (41)] were single-centre RCTs and were performed within a University Department of Orthodontics. They were conducted in China (ShenZhen) (42), (Beijng) (41), and in Japan (Sendai) (43) and published in 2012, 2020, and 2021. These three articles analyzed growing patients who required maxillary protraction.
Characteristics of included studies.
| Authors of the study | Ge et al. (42) | Seiryu et al. (43) | Liang et al. (41) |
|---|---|---|---|
| Study design | RCT | RCT | RCT |
| Sample size | 43 subjects 20 in miniscrew group (MG) 23 in group without miniscrew (NMG) | 39 subjects 19 in miniscrew group (MG) 20 in group without miniscrew (NMG) | 41 subjects 20 in miniscrew group (MG) 21 in group without miniscrew (NMG) |
| Mean age of the subjects | MG: 10 years and 4 months NMG: 10 years and 6 months | MG: 11 years and 1 months ± 1 years and 3 months NMG: 10 years and 5 months ± 1 years and 8 months | MG: 10.75 ± 1.3 years NMG: 10.5 ± 1.1 years |
| Sex of the subjects | MG: 11 F; 9 M NMG: 12 F; 11 M | MG: 7 F; 12 M NMG: 8 F; 12 M | MG: 12 F; 8 M NMG: 10 F; 11 M |
| Cervical Stage | CS 1–CS 3 | 28 subjects at CS 3 8 subjects at CS 4 3 subjects at CS 5 | Not available |
| Inclusion criteria | Skeletal and dental Class III malocclusion with maxillary deficiency (ANB < 0°; Wits appraisal < −2 mm) -Reverse incisor relationship and positive overbite | Skeletal Class III (ANB ≤ 2.5°), measured by inspection of initial lateral cephalograms. Overjet ≥0, measured during initial cast analysis Undergoing circumpubertal phase of skeletal development (CS 3–CS 5) | Maxillary deficiency (distance from point A to nasion perpendicular <0 mm) Skeletal Class III malocclusion -An Angle Class III occlusal relationship with an anterior crossbite a Concave lateral profile with midface deficiency Prepubescent stage of skeletal age, as verified by the hand-wrist radiographs |
| Exclusion criteria | No significant skeletal asymmetry No systemic diseases or congenital deformities | -No congenital or systemic disease -No skeletal asymmetry -No missing teeth -No temporomandibular joint disorder | -Prior orthodontic or orthopaedic treatment Craniofacial anomalies or syndromes -Poor compliance of patient |
| Type of appliance used for anchorage for the facemask | MG: 2 miniscrews NMG: bonded Hyrax expander | MG: lingual arch with soldered hooks and connected to a palatal miniscrew NMG: Lingual arch with soldered hooks | MG: two customized miniplates NMG: banded rapid maxillary expander |
| Anchorage points (skeletal/dental) | MG: the zygomatic buttress of the maxilla NMG: the specific teeth to which the expander is anchored are not reported | MG: first permanent molars plus one miniscrew in the anterior region of the palate NMG: first permanent molars | MG: the anterior segment on both sides of the maxilla NMG: maxillary first molars and first premolars or deciduous first molars |
| Force used for the facemask and inclination of elastics | MG: forces of 200–250 gr per side. Elastics inclined at a 30° angle downward to the occlusal plane NMG: forces of 400–500 gr per side. Elastics inclined with a downward and forward vector | MG: forces of 250 g per side. Elastics inclined 0–3° from the occlusal plane NMG: forces of 250 g per side. Elastics inclined 0–3° downward to the occlusal plane | MG: 400–500 gr per side Elastics inclined 30° below the occlusal plane NMG: 400–500 gr per side Elastics inclined 30° below the occlusal plane |
| Measurement technique | Cephalograms | Cephalograms | CBCT |
| Type of outcomes evaluated | ANB Wits SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP |
| Duration of treatment | MG group: mean treatment duration: 11 months NMG group: mean treatment duration: 1 year and 1 month | MG group: 1 year, 9 months ± 9.9 months NMG: 1 year, 9 months ± 10.2 months | MG group: 10.6 months NMG: 12.1 months |
| Authors of the study | Ge et al. (42) | Seiryu et al. (43) | Liang et al. (41) |
|---|---|---|---|
| Study design | RCT | RCT | RCT |
| Sample size | 43 subjects 20 in miniscrew group (MG) 23 in group without miniscrew (NMG) | 39 subjects 19 in miniscrew group (MG) 20 in group without miniscrew (NMG) | 41 subjects 20 in miniscrew group (MG) 21 in group without miniscrew (NMG) |
| Mean age of the subjects | MG: 10 years and 4 months NMG: 10 years and 6 months | MG: 11 years and 1 months ± 1 years and 3 months NMG: 10 years and 5 months ± 1 years and 8 months | MG: 10.75 ± 1.3 years NMG: 10.5 ± 1.1 years |
| Sex of the subjects | MG: 11 F; 9 M NMG: 12 F; 11 M | MG: 7 F; 12 M NMG: 8 F; 12 M | MG: 12 F; 8 M NMG: 10 F; 11 M |
| Cervical Stage | CS 1–CS 3 | 28 subjects at CS 3 8 subjects at CS 4 3 subjects at CS 5 | Not available |
| Inclusion criteria | Skeletal and dental Class III malocclusion with maxillary deficiency (ANB < 0°; Wits appraisal < −2 mm) -Reverse incisor relationship and positive overbite | Skeletal Class III (ANB ≤ 2.5°), measured by inspection of initial lateral cephalograms. Overjet ≥0, measured during initial cast analysis Undergoing circumpubertal phase of skeletal development (CS 3–CS 5) | Maxillary deficiency (distance from point A to nasion perpendicular <0 mm) Skeletal Class III malocclusion -An Angle Class III occlusal relationship with an anterior crossbite a Concave lateral profile with midface deficiency Prepubescent stage of skeletal age, as verified by the hand-wrist radiographs |
| Exclusion criteria | No significant skeletal asymmetry No systemic diseases or congenital deformities | -No congenital or systemic disease -No skeletal asymmetry -No missing teeth -No temporomandibular joint disorder | -Prior orthodontic or orthopaedic treatment Craniofacial anomalies or syndromes -Poor compliance of patient |
| Type of appliance used for anchorage for the facemask | MG: 2 miniscrews NMG: bonded Hyrax expander | MG: lingual arch with soldered hooks and connected to a palatal miniscrew NMG: Lingual arch with soldered hooks | MG: two customized miniplates NMG: banded rapid maxillary expander |
| Anchorage points (skeletal/dental) | MG: the zygomatic buttress of the maxilla NMG: the specific teeth to which the expander is anchored are not reported | MG: first permanent molars plus one miniscrew in the anterior region of the palate NMG: first permanent molars | MG: the anterior segment on both sides of the maxilla NMG: maxillary first molars and first premolars or deciduous first molars |
| Force used for the facemask and inclination of elastics | MG: forces of 200–250 gr per side. Elastics inclined at a 30° angle downward to the occlusal plane NMG: forces of 400–500 gr per side. Elastics inclined with a downward and forward vector | MG: forces of 250 g per side. Elastics inclined 0–3° from the occlusal plane NMG: forces of 250 g per side. Elastics inclined 0–3° downward to the occlusal plane | MG: 400–500 gr per side Elastics inclined 30° below the occlusal plane NMG: 400–500 gr per side Elastics inclined 30° below the occlusal plane |
| Measurement technique | Cephalograms | Cephalograms | CBCT |
| Type of outcomes evaluated | ANB Wits SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP |
| Duration of treatment | MG group: mean treatment duration: 11 months NMG group: mean treatment duration: 1 year and 1 month | MG group: 1 year, 9 months ± 9.9 months NMG: 1 year, 9 months ± 10.2 months | MG group: 10.6 months NMG: 12.1 months |
MG: miniscrew group.
NMG: no miniscrew group.
Characteristics of included studies.
| Authors of the study | Ge et al. (42) | Seiryu et al. (43) | Liang et al. (41) |
|---|---|---|---|
| Study design | RCT | RCT | RCT |
| Sample size | 43 subjects 20 in miniscrew group (MG) 23 in group without miniscrew (NMG) | 39 subjects 19 in miniscrew group (MG) 20 in group without miniscrew (NMG) | 41 subjects 20 in miniscrew group (MG) 21 in group without miniscrew (NMG) |
| Mean age of the subjects | MG: 10 years and 4 months NMG: 10 years and 6 months | MG: 11 years and 1 months ± 1 years and 3 months NMG: 10 years and 5 months ± 1 years and 8 months | MG: 10.75 ± 1.3 years NMG: 10.5 ± 1.1 years |
| Sex of the subjects | MG: 11 F; 9 M NMG: 12 F; 11 M | MG: 7 F; 12 M NMG: 8 F; 12 M | MG: 12 F; 8 M NMG: 10 F; 11 M |
| Cervical Stage | CS 1–CS 3 | 28 subjects at CS 3 8 subjects at CS 4 3 subjects at CS 5 | Not available |
| Inclusion criteria | Skeletal and dental Class III malocclusion with maxillary deficiency (ANB < 0°; Wits appraisal < −2 mm) -Reverse incisor relationship and positive overbite | Skeletal Class III (ANB ≤ 2.5°), measured by inspection of initial lateral cephalograms. Overjet ≥0, measured during initial cast analysis Undergoing circumpubertal phase of skeletal development (CS 3–CS 5) | Maxillary deficiency (distance from point A to nasion perpendicular <0 mm) Skeletal Class III malocclusion -An Angle Class III occlusal relationship with an anterior crossbite a Concave lateral profile with midface deficiency Prepubescent stage of skeletal age, as verified by the hand-wrist radiographs |
| Exclusion criteria | No significant skeletal asymmetry No systemic diseases or congenital deformities | -No congenital or systemic disease -No skeletal asymmetry -No missing teeth -No temporomandibular joint disorder | -Prior orthodontic or orthopaedic treatment Craniofacial anomalies or syndromes -Poor compliance of patient |
| Type of appliance used for anchorage for the facemask | MG: 2 miniscrews NMG: bonded Hyrax expander | MG: lingual arch with soldered hooks and connected to a palatal miniscrew NMG: Lingual arch with soldered hooks | MG: two customized miniplates NMG: banded rapid maxillary expander |
| Anchorage points (skeletal/dental) | MG: the zygomatic buttress of the maxilla NMG: the specific teeth to which the expander is anchored are not reported | MG: first permanent molars plus one miniscrew in the anterior region of the palate NMG: first permanent molars | MG: the anterior segment on both sides of the maxilla NMG: maxillary first molars and first premolars or deciduous first molars |
| Force used for the facemask and inclination of elastics | MG: forces of 200–250 gr per side. Elastics inclined at a 30° angle downward to the occlusal plane NMG: forces of 400–500 gr per side. Elastics inclined with a downward and forward vector | MG: forces of 250 g per side. Elastics inclined 0–3° from the occlusal plane NMG: forces of 250 g per side. Elastics inclined 0–3° downward to the occlusal plane | MG: 400–500 gr per side Elastics inclined 30° below the occlusal plane NMG: 400–500 gr per side Elastics inclined 30° below the occlusal plane |
| Measurement technique | Cephalograms | Cephalograms | CBCT |
| Type of outcomes evaluated | ANB Wits SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP |
| Duration of treatment | MG group: mean treatment duration: 11 months NMG group: mean treatment duration: 1 year and 1 month | MG group: 1 year, 9 months ± 9.9 months NMG: 1 year, 9 months ± 10.2 months | MG group: 10.6 months NMG: 12.1 months |
| Authors of the study | Ge et al. (42) | Seiryu et al. (43) | Liang et al. (41) |
|---|---|---|---|
| Study design | RCT | RCT | RCT |
| Sample size | 43 subjects 20 in miniscrew group (MG) 23 in group without miniscrew (NMG) | 39 subjects 19 in miniscrew group (MG) 20 in group without miniscrew (NMG) | 41 subjects 20 in miniscrew group (MG) 21 in group without miniscrew (NMG) |
| Mean age of the subjects | MG: 10 years and 4 months NMG: 10 years and 6 months | MG: 11 years and 1 months ± 1 years and 3 months NMG: 10 years and 5 months ± 1 years and 8 months | MG: 10.75 ± 1.3 years NMG: 10.5 ± 1.1 years |
| Sex of the subjects | MG: 11 F; 9 M NMG: 12 F; 11 M | MG: 7 F; 12 M NMG: 8 F; 12 M | MG: 12 F; 8 M NMG: 10 F; 11 M |
| Cervical Stage | CS 1–CS 3 | 28 subjects at CS 3 8 subjects at CS 4 3 subjects at CS 5 | Not available |
| Inclusion criteria | Skeletal and dental Class III malocclusion with maxillary deficiency (ANB < 0°; Wits appraisal < −2 mm) -Reverse incisor relationship and positive overbite | Skeletal Class III (ANB ≤ 2.5°), measured by inspection of initial lateral cephalograms. Overjet ≥0, measured during initial cast analysis Undergoing circumpubertal phase of skeletal development (CS 3–CS 5) | Maxillary deficiency (distance from point A to nasion perpendicular <0 mm) Skeletal Class III malocclusion -An Angle Class III occlusal relationship with an anterior crossbite a Concave lateral profile with midface deficiency Prepubescent stage of skeletal age, as verified by the hand-wrist radiographs |
| Exclusion criteria | No significant skeletal asymmetry No systemic diseases or congenital deformities | -No congenital or systemic disease -No skeletal asymmetry -No missing teeth -No temporomandibular joint disorder | -Prior orthodontic or orthopaedic treatment Craniofacial anomalies or syndromes -Poor compliance of patient |
| Type of appliance used for anchorage for the facemask | MG: 2 miniscrews NMG: bonded Hyrax expander | MG: lingual arch with soldered hooks and connected to a palatal miniscrew NMG: Lingual arch with soldered hooks | MG: two customized miniplates NMG: banded rapid maxillary expander |
| Anchorage points (skeletal/dental) | MG: the zygomatic buttress of the maxilla NMG: the specific teeth to which the expander is anchored are not reported | MG: first permanent molars plus one miniscrew in the anterior region of the palate NMG: first permanent molars | MG: the anterior segment on both sides of the maxilla NMG: maxillary first molars and first premolars or deciduous first molars |
| Force used for the facemask and inclination of elastics | MG: forces of 200–250 gr per side. Elastics inclined at a 30° angle downward to the occlusal plane NMG: forces of 400–500 gr per side. Elastics inclined with a downward and forward vector | MG: forces of 250 g per side. Elastics inclined 0–3° from the occlusal plane NMG: forces of 250 g per side. Elastics inclined 0–3° downward to the occlusal plane | MG: 400–500 gr per side Elastics inclined 30° below the occlusal plane NMG: 400–500 gr per side Elastics inclined 30° below the occlusal plane |
| Measurement technique | Cephalograms | Cephalograms | CBCT |
| Type of outcomes evaluated | ANB Wits SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP U1-SN Complications | ANB SNA SNB SN-MP |
| Duration of treatment | MG group: mean treatment duration: 11 months NMG group: mean treatment duration: 1 year and 1 month | MG group: 1 year, 9 months ± 9.9 months NMG: 1 year, 9 months ± 10.2 months | MG group: 10.6 months NMG: 12.1 months |
MG: miniscrew group.
NMG: no miniscrew group.
Characteristics of the participants
In the study by Ge et al. (42), the inclusion criteria were the presence of a skeletal and dental Class III malocclusion with maxillary deficiency (ANB < 0 degrees; Wits appraisal < −2 mm) and a reverse incisor relationship and positive overbite. In the study by Seiryu et al. (43) the overjet had to be ≥ 0 with a skeletal Class III (ANB ≤ 2.5 degrees), measured by inspection of initial lateral cephalograms. In the study by Liang et al. (41) patients had to have a maxillary deficiency, a skeletal and dental Class III malocclusion with an anterior crossbite and a concave profile with midface deficiency.
In two studies the Cervical Stage (CS) in cervical vertebral maturation (44) was considered. In the third study (41) CSs were not considered, but an assessment of skeletal age of patients was based on hand-twist radiographs. In one article (42) patients were in a pre-pubertal and pubertal stage (CS 1–CS 3) while in the other article (43) both pubertal and post-pubertal patients (CS 3–CS 5) were comprised. In the study by Liang et al. (41) all patients had to be prepubertals. Moreover, in one study (43) two patients refused to participate but no patients dropped out or were excluded during treatment. In the other study (42) two patients (one per group) were excluded for poor cooperation, and four patients in the skeletally anchored group were excluded for mobility of the miniscrews. In the third study (41) no dropouts were reported. The age of patients was 10 years and 5 months (mean) at the start of treatment (42); between 7 years, 5 months and 13 years, 8 months in another study (43) and 10 years and 6 months in the other study (41).
Characteristics of the intervention and comparisons
To assemble the results from the different included studies, the group with skeletally anchored facemask was designated Miniscrew Group (MG) and the group with dental-anchored facemask was denominated No Miniscrew Group (NMG).
The included studies compared the dento-skeletal effects after a treatment with a skeletally anchored facemask in comparison with a facemask with a tooth-borne anchorage in Class III patients. Anchorage points in the maxilla of the three included studies are summarized in Supplementary Figure 2. In one study (42) the skeletally anchored facemask (Miniscrew Group) was connected by elastics to two miniscrews of 2 mm in diameter and 14 mm in length inserted at the zygomatic buttress of the maxilla. Elastics pulled 200 g to 250 g of force to the miniscrews on each side at a 30 degrees angle downward to the occlusal plane. The control group (No Miniscrew Group) was treated with a bonded rapid maxillary expander (Hyrax type) with hooks for a Petit facemask. Elastics produced forces of 400 g–500 g per side in a downward and forward vector.
In another study (43) a lingual arch with soldered hooks was fixed to the maxillary arch in both groups. In the skeletally anchored facemask group (Miniscrew Group), one miniscrew with a 1.4 mm diameter and length from 8 to 10 mm was inserted in the anterior region of the palate and the lingual arch was attached to the miniscrew by tying with a ligature wire and fixing with resin. In both groups a protractive force of 250 g per side was applied and the direction of the traction force was <3 degrees from the occlusal plane.
In the third study (41), skeletally anchored facemask (Miniscrew Group) was attached to two customised miniplates located at the anterior segment on both sides of the maxilla. The precise location of placing the miniplates was decided based on the cortical bone thickness, bone density, and positions of roots and permanent tooth germs from CBCT images. After decided the position of miniscrews, a miniplate (2–3 miniscrews per miniplate) was designed according to the position of the miniscrew. Miniscrews were 1.2–2.0 mm in diameter, 4–6 mm in length. Four weeks after insertion, traction forces were applied to the miniplates. In the tooth-anchored facemask (No Miniscrew Group), a rapid maxillary expander with anterior hooks was bonded on the maxillary first molars and first premolars or deciduous first molars. Forces were 400–500 g on each side, elastics were pulled at 30 degrees below the occlusal plane.
Characteristics of the outcomes
The outcomes of included studies were the dento-skeletal and soft tissue measurements. In the study by Ge et al. (42) 24 variables were undertaken, including maxillary, mandibular, maxillo-mandibular, dental, vertical, and soft tissue measurements. In the study by Seiryu et al. (43) 12 variables were measured and reported for all patients included. In Liang et al. (41) 30 variables were analyzed in the two groups at the beginning and at the end of treatment. Six variables (five angular and one linear) were considered from the three studies to be included in the systematic review and meta-analysis (ANB angle, Wits appraisal, SNA angle, SNB angle, SN-MP angle, and U1-MP angle). In one study (41) U1-MP angle was not included in the meta-analysis because its definition was not comparable to that of the other two studies included. Primary outcomes were the intermaxillary sagittal skeletal effects (ANB and Wits appraisal). Wits appraisal was not calculated in two studies (41,43). The number of treatment complications and the possible exclusion of participants were also reported in two studies (42,43) and analyzed in the meta-analysis.
Risk of bias within studies and quality of evidence
The risk of bias of the included RCTs was assessed through the version 2 of the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2) and it is presented graphically in Figure 1.
Risk of bias in included studies.
Overall risk
Ge et al. (42), was considered at high risk of bias because it showed high risk of bias for the domains D2, D3, and D4.
Seiryu et al. (43), was considered at low risk of bias because it showed low risk of bias for all domains.
Liang et al. (41), was considered at high risk of bias because it showed high risk of bias for the domains D1 and D4.
Risk of bias was considered high for two studies, and this was due to randomization bias (selection bias as the lack of allocation concealment, blinding), missing data, selective reporting, and bias due to outcome measurement.
Results of individual studies and data synthesis
Six continuous outcomes (ANB angle, Wits appraisal, SNA angle, SNB angle, SN-MP angle, and U1-SN angle) and one binary outcome (presence of complications during treatment) were included in the meta-analysis. The two groups were denominated Miniscrew Group and No Miniscrew Group to distinguish the group where the facemask was skeletally anchored (Miniscrew Group, MG) and the group where the facemask was anchored to the teeth (No Miniscrew Group, NMG).
Summary of the data
The summary results of the data are expressed in Table 3.
Comparison between sagittal dento-skeletal outcomes produced by a skeletally anchored facemask with miniscrew versus a traditional tooth-anchored facemask (without miniscrew) in included studies in the systematic review.
| Study | Facemask with miniscrew (T2–T1) | Facemask without miniscrew (T2–T1) | Mean difference (MD)/Risk ratio (RR) between the two groups (Miniscrew- No miniscrew) | Statistically significant differences between the two groups | ||||
|---|---|---|---|---|---|---|---|---|
| Events/Mean | SD | Total subjects | Events/Mean | SD | Total subjects | |||
| Ge et al. (42) Sample size: 43 patients 20 in miniscrew group (plus four subjects excluded for mobility of miniscrews) 23 in group without miniscrew | ||||||||
| 1. ANB | 4.37 (Mean) | 1.73 | 20 | 4.42 (Mean) | 1.73 | 23 | −0.05 (MD) | No |
| 2. Wits | 4.83 (Mean) | 3.01 | 20 | 5.33 (Mean) | 2.90 | 23 | −0.50 (MD) | No |
| 3. SNA | 2.58 (Mean) | 1.59 | 20 | 2.62 (Mean) | 2.66 | 23 | −0.04 (MD) | No |
| 4. SNB | −1.80 (Mean) | 0.80 | 20 | −1.79 (Mean) | 1.25 | 23 | −0.01 (MD) | No |
| 5. SN-MP | 1.84 (Mean) | 1.52 | 20 | 1.98 (Mean) | 1.16 | 23 | −0.14 (MD) | No |
| 6. U1-SN | 1.88 (Mean) | 3.51 | 20 | 8.29 (Mean) | 3.27 | 23 | −6.41 (MD) | Yes (P < 0.01) |
| 7. Complications | 4 (Events) | 24 | 0 (Events) | 23 | 8.64 (RR) | |||
| Seiryu et al. (43) Sample size: 39 patients 19 in miniscrew group 20 in group without miniscrew | ||||||||
| 1. ANB | 2.0 (Mean) | 1.3 | 19 | 1.2 (Mean) | 1.22 | 20 | 0.8 (MD) | Yes (P =0.034) |
| 2. SNA | 2.2 (Mean) | 1.3 | 19 | 1.1 (Mean) | 1 | 20 | 1.1 (MD) | Yes (P = 0.006) |
| 3. SNB | 0.1 (Mean) | 1.3 | 19 | 0 (Mean) | 1 | 20 | 0.1 (MD) | No (P = 0.531) |
| 4. SN-MP | −0.1 (Mean) | 1.3 | 19 | −0.1 (Mean) | 1.2 | 20 | 0 (MD) | No (P = 0.976) |
| 5. U1-SN | −0.4 (Mean) | 4.2 | 19 | 4.6 (Mean) | 4.5 | 20 | −5.0 (MD) | Yes (P = 0.001) |
| Complications | 3 (Events) | 19 | 0 (Events) | 20 | 7.35 (RR) | |||
| Liang et al. (41) Sample size: 41 patients 20 in miniscrew group 21 in group without miniscrew | ||||||||
| 1. ANB | 3.14 (Mean) | 1.64 | 20 | 2.69 (Mean) | 1.42 | 21 | 0.45 (MD) | No (P = 0.359) |
| 2. SNA | 2.65 (Mean) | 1.02 | 20 | 1.85 (Mean) | 1.23 | 21 | 0.8 (MD) | Yes (P = 0.012) |
| 3. SNB | −0.49 (Mean) | 1.70 | 20 | −0.84 (Mean) | 1.15 | 21 | 0.35 (MD) | No (0.459) |
| 4. SN-MP | 0.09 (Mean) | 1.68 | 20 | 1.08 (Mean) | 1.95 | 21 | -0.99 (MD) | No (P = 0.064) |
| Study | Facemask with miniscrew (T2–T1) | Facemask without miniscrew (T2–T1) | Mean difference (MD)/Risk ratio (RR) between the two groups (Miniscrew- No miniscrew) | Statistically significant differences between the two groups | ||||
|---|---|---|---|---|---|---|---|---|
| Events/Mean | SD | Total subjects | Events/Mean | SD | Total subjects | |||
| Ge et al. (42) Sample size: 43 patients 20 in miniscrew group (plus four subjects excluded for mobility of miniscrews) 23 in group without miniscrew | ||||||||
| 1. ANB | 4.37 (Mean) | 1.73 | 20 | 4.42 (Mean) | 1.73 | 23 | −0.05 (MD) | No |
| 2. Wits | 4.83 (Mean) | 3.01 | 20 | 5.33 (Mean) | 2.90 | 23 | −0.50 (MD) | No |
| 3. SNA | 2.58 (Mean) | 1.59 | 20 | 2.62 (Mean) | 2.66 | 23 | −0.04 (MD) | No |
| 4. SNB | −1.80 (Mean) | 0.80 | 20 | −1.79 (Mean) | 1.25 | 23 | −0.01 (MD) | No |
| 5. SN-MP | 1.84 (Mean) | 1.52 | 20 | 1.98 (Mean) | 1.16 | 23 | −0.14 (MD) | No |
| 6. U1-SN | 1.88 (Mean) | 3.51 | 20 | 8.29 (Mean) | 3.27 | 23 | −6.41 (MD) | Yes (P < 0.01) |
| 7. Complications | 4 (Events) | 24 | 0 (Events) | 23 | 8.64 (RR) | |||
| Seiryu et al. (43) Sample size: 39 patients 19 in miniscrew group 20 in group without miniscrew | ||||||||
| 1. ANB | 2.0 (Mean) | 1.3 | 19 | 1.2 (Mean) | 1.22 | 20 | 0.8 (MD) | Yes (P =0.034) |
| 2. SNA | 2.2 (Mean) | 1.3 | 19 | 1.1 (Mean) | 1 | 20 | 1.1 (MD) | Yes (P = 0.006) |
| 3. SNB | 0.1 (Mean) | 1.3 | 19 | 0 (Mean) | 1 | 20 | 0.1 (MD) | No (P = 0.531) |
| 4. SN-MP | −0.1 (Mean) | 1.3 | 19 | −0.1 (Mean) | 1.2 | 20 | 0 (MD) | No (P = 0.976) |
| 5. U1-SN | −0.4 (Mean) | 4.2 | 19 | 4.6 (Mean) | 4.5 | 20 | −5.0 (MD) | Yes (P = 0.001) |
| Complications | 3 (Events) | 19 | 0 (Events) | 20 | 7.35 (RR) | |||
| Liang et al. (41) Sample size: 41 patients 20 in miniscrew group 21 in group without miniscrew | ||||||||
| 1. ANB | 3.14 (Mean) | 1.64 | 20 | 2.69 (Mean) | 1.42 | 21 | 0.45 (MD) | No (P = 0.359) |
| 2. SNA | 2.65 (Mean) | 1.02 | 20 | 1.85 (Mean) | 1.23 | 21 | 0.8 (MD) | Yes (P = 0.012) |
| 3. SNB | −0.49 (Mean) | 1.70 | 20 | −0.84 (Mean) | 1.15 | 21 | 0.35 (MD) | No (0.459) |
| 4. SN-MP | 0.09 (Mean) | 1.68 | 20 | 1.08 (Mean) | 1.95 | 21 | -0.99 (MD) | No (P = 0.064) |
T1: start of treatment.
T2: end of treatment.
Comparison between sagittal dento-skeletal outcomes produced by a skeletally anchored facemask with miniscrew versus a traditional tooth-anchored facemask (without miniscrew) in included studies in the systematic review.
| Study | Facemask with miniscrew (T2–T1) | Facemask without miniscrew (T2–T1) | Mean difference (MD)/Risk ratio (RR) between the two groups (Miniscrew- No miniscrew) | Statistically significant differences between the two groups | ||||
|---|---|---|---|---|---|---|---|---|
| Events/Mean | SD | Total subjects | Events/Mean | SD | Total subjects | |||
| Ge et al. (42) Sample size: 43 patients 20 in miniscrew group (plus four subjects excluded for mobility of miniscrews) 23 in group without miniscrew | ||||||||
| 1. ANB | 4.37 (Mean) | 1.73 | 20 | 4.42 (Mean) | 1.73 | 23 | −0.05 (MD) | No |
| 2. Wits | 4.83 (Mean) | 3.01 | 20 | 5.33 (Mean) | 2.90 | 23 | −0.50 (MD) | No |
| 3. SNA | 2.58 (Mean) | 1.59 | 20 | 2.62 (Mean) | 2.66 | 23 | −0.04 (MD) | No |
| 4. SNB | −1.80 (Mean) | 0.80 | 20 | −1.79 (Mean) | 1.25 | 23 | −0.01 (MD) | No |
| 5. SN-MP | 1.84 (Mean) | 1.52 | 20 | 1.98 (Mean) | 1.16 | 23 | −0.14 (MD) | No |
| 6. U1-SN | 1.88 (Mean) | 3.51 | 20 | 8.29 (Mean) | 3.27 | 23 | −6.41 (MD) | Yes (P < 0.01) |
| 7. Complications | 4 (Events) | 24 | 0 (Events) | 23 | 8.64 (RR) | |||
| Seiryu et al. (43) Sample size: 39 patients 19 in miniscrew group 20 in group without miniscrew | ||||||||
| 1. ANB | 2.0 (Mean) | 1.3 | 19 | 1.2 (Mean) | 1.22 | 20 | 0.8 (MD) | Yes (P =0.034) |
| 2. SNA | 2.2 (Mean) | 1.3 | 19 | 1.1 (Mean) | 1 | 20 | 1.1 (MD) | Yes (P = 0.006) |
| 3. SNB | 0.1 (Mean) | 1.3 | 19 | 0 (Mean) | 1 | 20 | 0.1 (MD) | No (P = 0.531) |
| 4. SN-MP | −0.1 (Mean) | 1.3 | 19 | −0.1 (Mean) | 1.2 | 20 | 0 (MD) | No (P = 0.976) |
| 5. U1-SN | −0.4 (Mean) | 4.2 | 19 | 4.6 (Mean) | 4.5 | 20 | −5.0 (MD) | Yes (P = 0.001) |
| Complications | 3 (Events) | 19 | 0 (Events) | 20 | 7.35 (RR) | |||
| Liang et al. (41) Sample size: 41 patients 20 in miniscrew group 21 in group without miniscrew | ||||||||
| 1. ANB | 3.14 (Mean) | 1.64 | 20 | 2.69 (Mean) | 1.42 | 21 | 0.45 (MD) | No (P = 0.359) |
| 2. SNA | 2.65 (Mean) | 1.02 | 20 | 1.85 (Mean) | 1.23 | 21 | 0.8 (MD) | Yes (P = 0.012) |
| 3. SNB | −0.49 (Mean) | 1.70 | 20 | −0.84 (Mean) | 1.15 | 21 | 0.35 (MD) | No (0.459) |
| 4. SN-MP | 0.09 (Mean) | 1.68 | 20 | 1.08 (Mean) | 1.95 | 21 | -0.99 (MD) | No (P = 0.064) |
| Study | Facemask with miniscrew (T2–T1) | Facemask without miniscrew (T2–T1) | Mean difference (MD)/Risk ratio (RR) between the two groups (Miniscrew- No miniscrew) | Statistically significant differences between the two groups | ||||
|---|---|---|---|---|---|---|---|---|
| Events/Mean | SD | Total subjects | Events/Mean | SD | Total subjects | |||
| Ge et al. (42) Sample size: 43 patients 20 in miniscrew group (plus four subjects excluded for mobility of miniscrews) 23 in group without miniscrew | ||||||||
| 1. ANB | 4.37 (Mean) | 1.73 | 20 | 4.42 (Mean) | 1.73 | 23 | −0.05 (MD) | No |
| 2. Wits | 4.83 (Mean) | 3.01 | 20 | 5.33 (Mean) | 2.90 | 23 | −0.50 (MD) | No |
| 3. SNA | 2.58 (Mean) | 1.59 | 20 | 2.62 (Mean) | 2.66 | 23 | −0.04 (MD) | No |
| 4. SNB | −1.80 (Mean) | 0.80 | 20 | −1.79 (Mean) | 1.25 | 23 | −0.01 (MD) | No |
| 5. SN-MP | 1.84 (Mean) | 1.52 | 20 | 1.98 (Mean) | 1.16 | 23 | −0.14 (MD) | No |
| 6. U1-SN | 1.88 (Mean) | 3.51 | 20 | 8.29 (Mean) | 3.27 | 23 | −6.41 (MD) | Yes (P < 0.01) |
| 7. Complications | 4 (Events) | 24 | 0 (Events) | 23 | 8.64 (RR) | |||
| Seiryu et al. (43) Sample size: 39 patients 19 in miniscrew group 20 in group without miniscrew | ||||||||
| 1. ANB | 2.0 (Mean) | 1.3 | 19 | 1.2 (Mean) | 1.22 | 20 | 0.8 (MD) | Yes (P =0.034) |
| 2. SNA | 2.2 (Mean) | 1.3 | 19 | 1.1 (Mean) | 1 | 20 | 1.1 (MD) | Yes (P = 0.006) |
| 3. SNB | 0.1 (Mean) | 1.3 | 19 | 0 (Mean) | 1 | 20 | 0.1 (MD) | No (P = 0.531) |
| 4. SN-MP | −0.1 (Mean) | 1.3 | 19 | −0.1 (Mean) | 1.2 | 20 | 0 (MD) | No (P = 0.976) |
| 5. U1-SN | −0.4 (Mean) | 4.2 | 19 | 4.6 (Mean) | 4.5 | 20 | −5.0 (MD) | Yes (P = 0.001) |
| Complications | 3 (Events) | 19 | 0 (Events) | 20 | 7.35 (RR) | |||
| Liang et al. (41) Sample size: 41 patients 20 in miniscrew group 21 in group without miniscrew | ||||||||
| 1. ANB | 3.14 (Mean) | 1.64 | 20 | 2.69 (Mean) | 1.42 | 21 | 0.45 (MD) | No (P = 0.359) |
| 2. SNA | 2.65 (Mean) | 1.02 | 20 | 1.85 (Mean) | 1.23 | 21 | 0.8 (MD) | Yes (P = 0.012) |
| 3. SNB | −0.49 (Mean) | 1.70 | 20 | −0.84 (Mean) | 1.15 | 21 | 0.35 (MD) | No (0.459) |
| 4. SN-MP | 0.09 (Mean) | 1.68 | 20 | 1.08 (Mean) | 1.95 | 21 | -0.99 (MD) | No (P = 0.064) |
T1: start of treatment.
T2: end of treatment.
ANB angle was evaluated in the three studies considered. The meta-analysis revealed that there were no statistically significant differences between the two types of treatment (pooled MD = 0.48 favouring Miniscrew, 95 per cent CI from −0.05 to 1.00, P = 0.07, I2 = 0 per cent, three studies, GRADE moderate) (Figure 2a).
Forest plots of the outcomes included in the meta-analysis (ANB; Wits appraisal; SNA; SNB; SN-MP; U1-SN; Complications).
Wits appraisal was measured only in one study (42). It increased in both groups with no significant differences between the two groups (pooled MD = −0.50 favouring No Miniscrew, 95 per cent CI from −2.27 to 1.27, P = 0.58, 1 study, GRADE low) (Figure 2b).
SNA angle was considered in all studies included. There was a significant difference between the two groups (pooled MD = 0.80 favouring Miniscrew, 95 per cent CI from 0.29 to 1.31, P = 0.002, I2 = 12 per cent, three studies, GRADE moderate) (Figure 2c).
SNB angle was investigated in all studies. There were no statistically significant differences between the two groups (pooled MD = 0.10 favouring No Miniscrew, 95 per cent CI from −0.31 to 0.52, P = 0.62, I2 = 0 per cent, three studies, GRADE moderate) (Figure 2d).
For the vertical measurements, the facial divergence angle (SN-MP angle) was evaluated. For the quantitative analysis there were no significant differences between the two groups (pooled MD = −0.26 favouring Miniscrew, 95 per cent CI from −0.79 to 0.26, P = 0.33, I2 = 7 per cent, three studies, GRADE moderate) (Figure 2e).
The inclination of the upper incisors relative to the cranial base (U1-SN angle) was significantly lesser at the end of treatment in MG relative to the NMG (pooled MD = −5.91 favouring Miniscrew, 95 per cent CI from −7.54 to −4.27, P < 0.00001, I2 = 0 per cent, two studies, GRADE moderate) (Figure 2f).
Regarding complications in one study (42) four patients were excluded for mobility of the miniscrews. In the other study (43) for three of the screws (three patients) the insertion direction was immediately changed because of root proximity of the miniscrews after CBCT imaging. There were significantly less complications in No Miniscrew Group (pooled RR = 7.98 favouring No Miniscrew, 95 per cent CI from 1.04 to 61.27, P = 0.05, I2 = 0 per cent, two studies, GRADE low) (Figure 2g).
A subgroup analysis by age (children versus adolescents) was not performed due to the similar age of patients of the three studies. Only one study (43) was at low risk of bias and therefore a subgroup analysis based on risk of bias was not performed.
Certainty of evidence and risk of reporting biases in syntheses
The quality of evidence of included studies was assessed with GRADE statement (Grading of Recommendations Assessment, Development, and Evaluation). The level of certainty of evidence was moderate for most variables. Summary of Findings Table (SoF) for GRADE statement is presented in Table 4. The quality of evidence was moderate for most of the variables due to the high risk of bias found in two out of three studies. The level of evidence was downgraded to low for Wits appraisal and complications due to high risk of bias and due to imprecision of studies included. Fewer than 10 studies were included in the quantitative synthesis, so it was not possible to measure publication bias. The broad search strategy, including the grey literature, reduced the probability of publication bias. Indirectness did not affect the level of certainty of evidence because both studies used outcomes that agreed with the PICOS questions of the systematic review.
Summary of Findings Table (SoF) for GRADE statement of included studies.
| Outcome | Mean difference (MD) or Risk ratio (RR) (95% CI) | Number of participants (studies) | Certainty of evidence (GRADE) | Key messages in simple terms |
|---|---|---|---|---|
| ANB | 0.48 [−0.05 to 1.00] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in ANB angle change between the two groups. |
| Wits | −0.50 [−2.27 to 1.27] (MD) | 43 subjects (1 RCTs) | ⊕⊕○○a,b Low | There is low evidence of the absence of difference in Wits appraisal change between the two groups. |
| SNA | 0.80 [0.29 to 1.31] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probablygreater maxillary protraction inthe skeletally anchored facemask. |
| SNB | 0.10 [−0.31 to 0.52] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in the change in mandibular sagittal position between the two groups. |
| SN-MP | −0.26 [−0.79 to 0.26] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | Skeletally anchored facemask and dental-anchored facemask probably do not differ in the change in facial divergence. |
| U1-SN | −5.91 [−7.54 to −4.27] (MD) | 82 subjects (2 RCTs) | ⊕⊕⊕○a Moderate | The use of a skeletally anchored facemask probably is associated with smaller change in proclination of the upper incisors compared to dental-anchored facemask. |
| Complications | 7.98 [1.04 to 61.27] (RR) | 86 subjects (2 RCTs) | ⊕⊕○○a,b Low | There is low evidence that there are more complications inskeletally anchored facemask compared to dental-anchored facemask. |
| Outcome | Mean difference (MD) or Risk ratio (RR) (95% CI) | Number of participants (studies) | Certainty of evidence (GRADE) | Key messages in simple terms |
|---|---|---|---|---|
| ANB | 0.48 [−0.05 to 1.00] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in ANB angle change between the two groups. |
| Wits | −0.50 [−2.27 to 1.27] (MD) | 43 subjects (1 RCTs) | ⊕⊕○○a,b Low | There is low evidence of the absence of difference in Wits appraisal change between the two groups. |
| SNA | 0.80 [0.29 to 1.31] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probablygreater maxillary protraction inthe skeletally anchored facemask. |
| SNB | 0.10 [−0.31 to 0.52] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in the change in mandibular sagittal position between the two groups. |
| SN-MP | −0.26 [−0.79 to 0.26] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | Skeletally anchored facemask and dental-anchored facemask probably do not differ in the change in facial divergence. |
| U1-SN | −5.91 [−7.54 to −4.27] (MD) | 82 subjects (2 RCTs) | ⊕⊕⊕○a Moderate | The use of a skeletally anchored facemask probably is associated with smaller change in proclination of the upper incisors compared to dental-anchored facemask. |
| Complications | 7.98 [1.04 to 61.27] (RR) | 86 subjects (2 RCTs) | ⊕⊕○○a,b Low | There is low evidence that there are more complications inskeletally anchored facemask compared to dental-anchored facemask. |
Participants: growing patients with Class III malocclusion, with indications for treatment with the facemask.
Intervention: treatment with facemask used in conjunction with skeletal anchorage in the maxilla.
Comparison: treatment with the facemask used in conjunction with dental anchorage in the upper arch.
Outcome: intermaxillary sagittal skeletal effects, additional outcomes as dentoalveolar effects, sagittal and vertical skeletal effects, patient-reported outcome measures, complications.
Study: RCTs.
95% CI: 95% confidence interval.
GRADE: Evidence grades. Grading of Recommendations Assessment, Development, and Evaluation.
Domains that lower the level of evidence:
aRoB (result from studies with high risk of bias).
bImprecision: wide confidence interval or only one study.
Summary of Findings Table (SoF) for GRADE statement of included studies.
| Outcome | Mean difference (MD) or Risk ratio (RR) (95% CI) | Number of participants (studies) | Certainty of evidence (GRADE) | Key messages in simple terms |
|---|---|---|---|---|
| ANB | 0.48 [−0.05 to 1.00] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in ANB angle change between the two groups. |
| Wits | −0.50 [−2.27 to 1.27] (MD) | 43 subjects (1 RCTs) | ⊕⊕○○a,b Low | There is low evidence of the absence of difference in Wits appraisal change between the two groups. |
| SNA | 0.80 [0.29 to 1.31] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probablygreater maxillary protraction inthe skeletally anchored facemask. |
| SNB | 0.10 [−0.31 to 0.52] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in the change in mandibular sagittal position between the two groups. |
| SN-MP | −0.26 [−0.79 to 0.26] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | Skeletally anchored facemask and dental-anchored facemask probably do not differ in the change in facial divergence. |
| U1-SN | −5.91 [−7.54 to −4.27] (MD) | 82 subjects (2 RCTs) | ⊕⊕⊕○a Moderate | The use of a skeletally anchored facemask probably is associated with smaller change in proclination of the upper incisors compared to dental-anchored facemask. |
| Complications | 7.98 [1.04 to 61.27] (RR) | 86 subjects (2 RCTs) | ⊕⊕○○a,b Low | There is low evidence that there are more complications inskeletally anchored facemask compared to dental-anchored facemask. |
| Outcome | Mean difference (MD) or Risk ratio (RR) (95% CI) | Number of participants (studies) | Certainty of evidence (GRADE) | Key messages in simple terms |
|---|---|---|---|---|
| ANB | 0.48 [−0.05 to 1.00] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in ANB angle change between the two groups. |
| Wits | −0.50 [−2.27 to 1.27] (MD) | 43 subjects (1 RCTs) | ⊕⊕○○a,b Low | There is low evidence of the absence of difference in Wits appraisal change between the two groups. |
| SNA | 0.80 [0.29 to 1.31] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probablygreater maxillary protraction inthe skeletally anchored facemask. |
| SNB | 0.10 [−0.31 to 0.52] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | There is probably no difference in the change in mandibular sagittal position between the two groups. |
| SN-MP | −0.26 [−0.79 to 0.26] (MD) | 123 subjects (3 RCTs) | ⊕⊕⊕○a Moderate | Skeletally anchored facemask and dental-anchored facemask probably do not differ in the change in facial divergence. |
| U1-SN | −5.91 [−7.54 to −4.27] (MD) | 82 subjects (2 RCTs) | ⊕⊕⊕○a Moderate | The use of a skeletally anchored facemask probably is associated with smaller change in proclination of the upper incisors compared to dental-anchored facemask. |
| Complications | 7.98 [1.04 to 61.27] (RR) | 86 subjects (2 RCTs) | ⊕⊕○○a,b Low | There is low evidence that there are more complications inskeletally anchored facemask compared to dental-anchored facemask. |
Participants: growing patients with Class III malocclusion, with indications for treatment with the facemask.
Intervention: treatment with facemask used in conjunction with skeletal anchorage in the maxilla.
Comparison: treatment with the facemask used in conjunction with dental anchorage in the upper arch.
Outcome: intermaxillary sagittal skeletal effects, additional outcomes as dentoalveolar effects, sagittal and vertical skeletal effects, patient-reported outcome measures, complications.
Study: RCTs.
95% CI: 95% confidence interval.
GRADE: Evidence grades. Grading of Recommendations Assessment, Development, and Evaluation.
Domains that lower the level of evidence:
aRoB (result from studies with high risk of bias).
bImprecision: wide confidence interval or only one study.
Discussion
Summary of evidence
This systematic review and meta-analysis aimed to gather scientific evidence related to sagittal dento-skeletal differences and other additional outcomes (dentoalveolar effects, sagittal and vertical effects, patient-outcome measures, and complications) between treatment of Class III patients with a dental-anchored facemask versus a skeletally anchored facemask. Only RCTs were included.
In this systematic review, selection bias was reduced including all languages, year, and type of publication. All types of published and unpublished articles were also included with an extended search into six databases including grey literature. Reviewer search and selection bias were reduced by including two independent authors in the selection of studies and extraction of relevant data and including two independent authors in the risk of bias and quality of evidence assessment. Data availability bias was reduced by contacting corresponding authors of those studies where missing information was present.
There are generally three types of anchorage on the maxilla for a facemask that are considered: a tooth-anchorage, a tooth-bone anchorage, and a bone-anchorage. Regarding bone-anchorage systems, there are essentially three anchorage zones for miniscrews or miniplates in maxillary protraction with a facemask: the lateral nasal wall, the zygomatic buttress of the maxilla, and the palate (24). In this systematic review, one study (42) used the zygomatic buttress of the maxilla as anchorage zone for the bone anchored group, in one study (41) miniplates were inserted in the lateral nasal wall, in another study (43) one miniscrew was inserted in the palate and connected with a ligature to a lingual arch.
Regarding the primary outcomes of this systematic review, ANB angle and Wits appraisal, in this systematic review and meta-analysis there were no statistical differences between the two groups of treatment (Figure 2). Wits appraisal was examined only in the study by Ge et al. (40). It improved in both groups by almost 5 mm (Figure 2b).
Differences in SNA angle between the two groups were statistically significant but clinically negligible (mean difference of 0.80 degrees, 95 per cent CI from 0.29 to 1.31) (Figure 2c). For this reason, it is not justifiable to use a skeletally anchored facemask to increase the protraction effect of the maxilla as this has not proved to have a clinically significant impact. The absence of differences in one study (40) could be related to greater elastic forces in the dental-anchored facemask with respect to bone-anchored facemask (400–450 gr per side versus 200–250 gr per side, respectively). It has been proposed that a greater maxillary protraction may be due to the magnitude of force given to the protraction Class III elastics (42). However, previous articles have reported no difference using 380–400 grams per side of elastic force in both groups (11,40).
In this systematic review and meta-analysis, vertical changes were investigated through SN-MP angle showing a lack of differences between the two groups (Figure 2e).
Proclination of the upper incisors relative to the cranial base (U1-SN) was much greater in the dental-anchored facemask group respect to the skeletally anchored facemask group, with a difference of almost 6 degrees between the groups (Figure 2f). Dental-anchored facemask is typically characterised by a loss of anchorage with a reduction of dental arch, a mesialization of upper molars and a proclination of upper incisors. In one study included in this systematic review (43) a lingual arch was used in both groups. In bone-anchored facemask group, one miniscrew linked to the lingual arch seemed to be sufficient to eliminate the proclination of maxillary incisors. Clinical implication of this outcome is important for those patients who present with a proclination of the upper incisors at the beginning of treatment. This circumstance can be a frequent condition of dental compensation in patients with a skeletal III Class malocclusion. For these patients, there is moderate evidence that a skeletally anchored facemask is probably more appropriate than a dental-anchored facemask. However, the clinician should also consider the surgical invasiveness of positioning of miniplates in the maxilla of growing patients, which implies the intervention of an experienced surgeon. Furthermore, the placement of palatal miniscrews in growing patients with erupting teeth, do not allow an easy and safe positioning of the miniscrews. In these cases a guided placement involves the execution of a CBCT with additional X-ray exposure.
Regarding other outcomes, complications of the procedure or treatment were investigated (Figure 2g). Loss of miniscrews, increased mobility or instability or miniscrews are considered as complications of patients with facemask with a skeletal anchorage. The included studies considered different locations of the miniscrew. In one study (42) miniscrews were placed in the zygomatic buttress of the maxilla, in the other (43) one miniscrew was placed in the palate, and it was connected to an intraoral appliance with a ligature. In the latter study (41) a customised miniplate was placed in the anterior region of both sides of the maxilla, and every miniplate was fixed by 2–3 miniscrews. In this study, two miniplates showed mobility but could still bear the force until the treatment was completed, therefore it was not considered a complication as this problem did not interrupt the treatment. Individual bone density was one of the main factors for a loss of a miniscrew (45,46). The loss of a miniscrew seems to be more frequent in older children than in children of 9 or 10 years and this could be due to a greater attention of parents to the oral hygiene of their younger child (45). The success rate of miniscrews in this systematic review was about 84 per cent, except one study in which the success rate was 100 per cent (41). This data agrees with that of the literature exploring the success rate of miniscrew into the zygomatic buttress of the maxilla (47,48) that reached 93 per cent only in one study (14). Mobility of a miniscrew does not appears a failure factor if the miniscrew is unstable but strong enough to withstand the protracting force of elastics (14). Inflammation of miniscrews (14), encapsulation of the miniscrew into the oral mucosa (45) and root proximity (49,50) are other possible complications that can reduce the effectiveness of the treatment.
GRADE assessment was used to define the level of evidence of the outcomes. GRADE evaluation was introduced to synthesize scientific evidence according to its certainty through a transparent and standardized process and the strength of the recommendations they perform (32). In this systematic review GRADE assessment was considered moderate for most of the outcomes due to a high risk of bias in two out of three studies. The high risk of bias was mostly due to selection bias (bias in the randomization process), performance bias (lack of blinding), and attrition bias. Low certainty of evidence was judged for Wits appraisal and for complications assessment due to high risk of bias of some studies included in the meta-analysis and due to imprecision. Imprecision was mainly due to the wide confidence interval around the effect, which does not allow a clear estimate of its magnitude. An assessment of 95 per cent confidence interval was considered the optimal primary approach to decisions regarding imprecision (37). The level of evidence demonstrated that for most of the outcomes probably there were no differences between the two groups. For complications (Figure 2g), statistically significant differences were proved favouring the dental-anchored facemask. Anyhow the overall certainty of the evidence for this outcome was low, therefore caution must be taken to interpret the certainty of evidence of this data.
Limitations
This systematic review and meta-analysis convey the scientific evidence of three studies with some differences. In two studies (41,42) a rapid maxillary expander was used to gain the anchorage in the dental-anchored facemask group. In another study (43) a maxillary lingual arch was used to anchor the facemask, with and without a miniscrew. Lingual arch is quite different from a rapid maxillary expander. In the rapid maxillary expander, the wire connects more teeth and the structure is more rigid (51,52). In the lingual arch the wire is anchored only at the level of the first upper molars. If no rigid structure connects the front teeth, when a force is applied by the hooks the wire could flex downwards and a distoinclination of the first permanent molars can occur. Furthermore, the three included studies did not use the same protraction force and the same inclination of the elastics. In two studies (41,42) elastics were inclined at a 30 degrees angle downward to the occlusal plane, in the other study (43) elastics were inclined 0–3 degrees from the occlusal plane. Elastics should be inclined by almost 30 degrees downwards to the occlusal plane to limit the counterclockwise and upward rotation of the occlusal plane (53). These differences could explain the different skeletal results obtained in the three studies.
One limitation of this systematic review and meta-analysis is that there are still no long-term RCTs evaluating the differences between skeletally anchored facemask therapy compared to standard RME/FM therapy.
Another limitation is that few RCTs (three) comparing facemask treatment with or without skeletal anchorage were included and two studies were at high risk of bias. More RCTs are needed to increase the evidence on this topic. The overall sample size was low with only 123 patients treated with skeletally anchored facemask or tooth-anchored facemask. There was no information regarding patient-reported outcomes and regarding their compliance for both procedures in all included studies.
The three included studies comprised only Asiatic patients. Typical craniofacial characteristics are present in Asiatic patients with Class III malocclusion, such as a significantly shorter anterior cranial base and a higher prevalence of maxillary deficiency compared to Caucasian subjects (54–56). RCTs with different racial groups could be carried out to define any different treatment results which may be related to their craniofacial features.
Conclusions
Skeletally anchored facemask is equally effective as the dental-anchored facemask in the short-term correction of Class III malocclusion in growing patients. Skeletally anchored facemask was associated to a greater increase of SNA angle at the end of treatment, although the difference (0.8 degrees) between the two treatment protocols was clinically negligible. The tooth-anchored facemask determined a greater proclination of the upper incisors at the end of the treatment. The skeletally anchored facemask was associated with more complications such as loss of miniscrews, reduced stability, or mobility of miniscrews.
Other information
Registration and protocol
The PRISMA statement 2020 was used to develop the protocol of this systematic review, to compose the article and for the compilation of the flowchart (PRISMA flow diagram) (57).
This systematic review and meta-analysis was registered on PROSPERO (PROSPERO 2020 CRD42020221982).
Acknowledgements
We thank Dr. Sara Del Ministro for her contribution in selection process of this review.
Funding
No funding was received for this research.
Conflicts of interest
None to declare.
Ethics approval
Not applicable (it is a systematic review)
Data availability
The data that are part of this article will be shared by the corresponding author after an appropriate request.
Supplementary material
Supplementary material is available at European Journal of Orthodontics online.
Supplementary Table 1 – Search strategy for electronic databases.
Supplementary Table 2 – Excluded articles and motivation for exclusion.
Supplementary Figure 1 – PRISMA 2020 statement flowchart.
Supplementary Figure 2 – Schematic illustration of the type of anchorage in the maxilla used in the included studies.
