Dental and Skeletal Effects of Palatal Expansion Techniques (PDF)

Journal of Oral Rehabilitation Journal of Oral Rehabilitation 2016 43; 543–564 Review Dental and skeletal effects of palatal expansion techniques: a systematic review of the current evidence from systematic reviews and meta-analyses
†a, R. RONGO*...

Journal of Oral Rehabilitation Journal of Oral Rehabilitation 2016 43; 543–564 Review Dental and skeletal effects of palatal expansion techniques: a systematic review of the current evidence from systematic reviews and meta-analyses
†a, R. RONGO*, R. VALLETTA*, R. MARTINA* & R. B U C C I * a , V. D ’ A N T O* A. M I C H E L O T T I * *Department of Neurosciences, Reproductive Sciences and Oral Sciences, School of Orthodontics and Temporomandibular disorders, University of Naples Federico II, Naples, and †Dentist Unit, Department of Pediatric Surgery, “Bambino Ges u” Children Hospital, Rome, Italy SUMMARY The aim was to assess the quality and to reported with moderate evidence after Slow summarise the findings of the Systematic Reviews Maxillary Expansion (SME). However, there is (SRs) and Meta-Analyses (MAs) on the dental and moderate evidence of a non-significant difference skeletal effects of maxillary expansion. Electronic between the two expansion modalities concerning and manual searches have been independently the short-term dentoalveolar effects. With both conducted by two investigators, up to February RME and SME, significant increase of skeletal 2015. SRs and MAs on the dentoalveolar and transversal dimension in the short-term is skeletal effects of fixed expanders were included. reported, and the skeletal expansion is always The methodological quality was assessed using the smaller than the dentoalveolar. Even though AMSTAR (A Measurement Tool to Assess dental relapse to some extent is present, long-term Systematic Reviews). The design of the primary results of the dentoalveolar effects show an studies included in each SR/MA was assessed with increase of the transversal dimension, supported the LRD (Level of Research Design scoring). The by moderate evidence for RME and low evidence evidence for each outcome was rated applying a for SME. Skeletal long-term effects are reported pre-determined scale. Twelve SRs/MAs were only with RME, supported by very low evidence. included. The AMSTAR scores ranged from 4 to 10. KEYWORDS: palatal expansion technique, mal- Two SRs/MAs included only RCTs. The current occlusion, review literature as topic, evidence- findings from SRs/MAs support with high evidence based dentistry, adolescent, growth and a significant increase in the short-term of maxillary development dentoalveolar transversal dimensions after Rapid Maxillary Expansion (RME). The same effect is Accepted for publication 7 February 2016 to the corresponding mandibular teeth (1). The preva- Background lence of this malocclusion ranges between 8 and 22% Posterior Crossbite (PXB) is a reverse position, on the in children in primary/mixed dentition (2, 3). Ana- transversal plane, of one or more maxillary teeth of tomical and myofunctional alterations as asymmetric the canine, premolar and molar region, with respect condylar positioning, asymmetric mandibular growth, dental discrepancies and dental asymmetries with Class II tendency on the crossbite side, have been a These two authors contributed equally to this work related to untreated PXB; (4–7) however, restoration © 2016 John Wiley & Sons Ltd doi: 10.1111/joor.12393 544 R. B U C C I et al. of normal growth and function have been reported Such approach has been previously adopted in the after the resolution of the crossbite (8, 9). orthodontic field to synthesise the evidence on Class Maxillary expansion (ME) is one of the treatment II orthopaedic functional treatment (15), but to the options for the correction of skeletal constriction of the best of our knowledge this is the first SR of SRs on upper jaw, with the intent to increase the transverse the effects of palatal expansion. widths of the maxilla through the opening of the mid- The aims of the present study were to: (i) evaluate palatal suture (10, 11). ME can be achieved by means the methodological quality of SRs and MAs on dental of different expansion rates and forces (Rapid Maxillary and skeletal effects of palatal expansion, and (ii) sum- Expansion–RME or Slow Maxillary Expansion–SME), marise the reported effects of treatment by appraising and with different appliances, and the choice among the evidence on which the results are based. these options can influence the resulting effects of the treatment, and the relative relapse. Methods With the rapid spread of the systematic approach to the primary literature, highly debated topics, such as Study selection and data collection the effect of ME, have been extensively studied in Sys- tematic Reviews (SRs) and Meta-Analyses (MAs), vari- Six electronic databases were investigated for the sys- able in quality and scope (12). Furthermore, MAs in tematic literature search. The survey covered the per- orthodontics are often affected by methodological flaws iod from the starting of the databases up to June (13), that in turn can affect the results provided (17). 2014. The search was later updated up to February Hence, when a number of SRs and MAs exist in 2015. Furthermore, hand-search of orthodontic jour- priority scientific areas, an Overview of reviews is the nals (European Journal of Orthodontics, American Journal type of research suggested to summarise and appraise of Orthodontics and Dentofacial Orthopedics and The Angle multiple results (12, 14). This work benefits to clini- Orthodontist) was performed, starting from the first cians who look for evidence on treatments of PXB volume available on the digital archives. An effort of and highlights potential ‘evidence gap’, informing exploration of the grey literature was performed reviewers about topic to be prioritised. among the abstracts collected on Web of Knowledge and Scopus databases and on the databases of scien- Table 1. Search strategy for each database and relative results Database Search strategy Results PubMed www.ncbi.nlm.nih.gov ((((((((‘Palatal Expansion Technique’[Mesh]) OR (maxillary expansion 119 OR palatal expansion))) AND ((‘Meta-Analysis’ [Publication Type]) OR ‘Review’ [Publication Type]))) NOT ‘Craniofacial Abnormalities’[Mesh]) NOT ‘Malocclusion, Angle Class III/therapy’[Mesh]) NOT ‘Orthognathic Surgery’[Mesh]) NOT ‘Cleft Palate’[Mesh] Web of Knowledge (WOK) TOPIC: (palatal expansion OR maxillary expansion) AND TOPIC: (review 105 https://webofknowledge.com/ OR meta-analysis) NOT TOPIC: (craniofacial syndrom*) NOT TOPIC: (surg*) NOT TOPIC: (angle class III) NOT TOPIC:(cleft palate) Scopus http://www.scopus.com/ (TITLE-ABS-KEY (palatal expansion OR maxillary expansion) AND TITLE- 69 ABS-KEY (review OR meta-analysis) AND NOT TITLE-ABS-KEY (craniofacial syndrom*) AND NOT TITLE-ABS-KEY (surg*) AND NOT TITLE-ABS-KEY (cleft palate) AND NOT TITLE-ABS-KEY (angle class iii)) Scientific Electronic Library Online (SciELO) (palatal expansion OR maxillary expansion) AND (review OR meta- 2 http://www.scielo.org analysis) Latin American and Caribbean Health Sciences (palatal expansion OR maxillary expansion) AND (review OR meta- 18 (LILACS) http://lilacs.bvsalud.org analysis) Cochrane Library www.cochranelibrary.com MeSH descriptor: [Palatal Expansion Technique] explode all trees 1 © 2016 John Wiley & Sons Ltd  EVIDENCE FROM SRS ON PALATAL EXPANSION 545 tific congresses (European Orthodontic Society and Inter- were scored 0 point. According to the number of cri- national Association of Dental Research). The search teria met, the methodological quality was rated as strategies applied for each database are shown in ‘Low’ (total AMSTAR ≤ 3), ‘Moderate’ (total AMSTAR Table 1 (see also: Table S1, PubMed search). 4 to 7) or ‘High’ (total AMSTAR ≥ 8) (17, 18). The inclusion criteria were: (i) SR or MA; (ii) Study The design of the primary studies included in each assessing dentoalveolar and/or skeletal effects of pala- SR/MA was reported with the Level of Research tal expansion techniques; (iii) Treatment performed Design scoring (LRD) (19, 20). This score, based on with fixed orthodontic expansion appliances. The the hierarchy of evidence, applies the following rates: exclusion criteria were: (i) Dual publication; (ii) System- i) SR, ii) Randomised clinical trial (RCT); iii) Study atic Reviews of SRs; (iii) Treatment performed with without randomisation (cohort study, case–control surgically assisted rapid maxillary expansion study), iv) Non-controlled study (cross-sectional (SARME); (iv) Cleft lip/palate diagnosis or craniofacial study, case series, case reports), v) Narrative review or syndrome diagnosis; (v) Expansion treatment per- expert opinion. formed in association with protraction headgear/face- The AMSTAR scores were independently rated by mask therapy; (vi) Updated publication; (vii) SR/MA two investigators (R.B. and R.R.), with no blinding focusing on treatments strategies others than fixed for the authors of the review, and disagreements were appliances (e.g. grinding/removable appliances). solved through discussion. The inter-examiner relia- All titles and abstracts were read and in case of bility for the AMSTAR scores was calculated by means uncertainty after the title-abstract reading the refer- of Cohen’s k coefficient. ence was included for full-text reading. The references that seemed to fulfil the inclusion criteria were read Synthesis of the results and quality of the body evidence in full-text, and only those which completely satisfied all the inclusion criteria were included. Whenever a The main outcomes of the included SRs/MAs were SR/MA addressed different interventions (e.g. fixed summarised according to: timing of the effect (short- and removable appliances), it was included, discarding or long-term), structure involved (dentoalveolar or the unnecessary data. To identify any further relevant skeletal effects), direction of the effect (transversal, missing paper, the reference lists of the included SRs/ vertical or sagittal), expansion modality (SME or MAs were analysed. RME) and appliance. Data about Authors, Year of publication, Study For each outcome, the quality of the body evidence design, Total number of subjects, Diagnosis, Interven- was rated according to a pre-determined set of levels tion, Expansion technique, Outcome, Methods, Quality of evidence. The criteria to downgrade the evidence of the primary studies, Results, Author’s conclusions were: the way the data were pooled (MA or narrative and Author’s comments on quality of the studies were synthesis), the number of studies/participants, and the extracted from the included SRs/MAs. When relevant quality of the primary studies assessing the outcome. data were not available in the publication, the authors Full explanation of the method is reported in Table 2. were contacted to obtain further information. The quality of the individual studies was not reas- Study selection and data extraction were indepen- sessed, but reported as assessed by the authors of the dently run by two operators (R.B. and R.R.). Dis- reviews. Similarly, whenever the quality of the body agreements between the two examiners were evidence was already assessed in the SR/MA it was discussed and solved to reach consensual decision. If not re-assessed, but reported as stated by the authors. necessary, a third operator (V.D.) was contacted for According to the number of downgrades, the evi- the final decision. dence was classified as: very low (>5 downgrades), low (4–5 downgrades), moderate (2–3 downgrades) or high (0–1 downgrade). It was assumed that for high evidence Quality assessment of the included SRs and MAs further research was very unlikely to change our confi- The methodological quality was assessed using ‘A dence in the estimate of effect; for moderate evidence Measurement Tool to Assess Systematic Reviews’ further research was likely to have an important impact (AMSTAR) (16). For each AMSTAR item, ‘yes’ on our confidence in the estimate of effect and may answers were scored 1 point, and the other answers change the estimate; for low evidence further research © 2016 John Wiley & Sons Ltd 546 R. B U C C I et al. Table 2. Objective criteria for rating the evidence of the reported outcomes Type of study No. of participants No. of studies Quality of primary studies No downgrade Meta-analysis >200 >10 If low for 75% of the included studies If the ‘Quality of primary’ study was not reported, we were conservative and assumed as 1 downgrade. If the ‘no. of participants’ was not reported, we assumed the same downgrade as for the ‘no. of studies’. was very likely to have an important impact on our The 12 SRs/MAs included and the data extracted confidence in the estimate of effect and was likely to are reported in Table 3 (10, 21–31). Four SRs were change the estimate; for very low evidence any estimate integrated with MA (21, 25, 28, 31). The total num- of effect was very uncertain. ber of subjects ranged from 89 to 997. The initial diagnosis revealed a unilateral or bilat- eral posterior crossbite in two studies (21, 23), general Results posterior crossbite, transverse discrepancy or con- stricted arches in four studies (24, 27, 28, 31), while Studies selection no initial diagnosis was reported in the rest of the Study selection is reported in the PRISMA flow diagram studies. The appliances studied were: Hyrax (bonded in Fig. 1 (see also: Table S2 for the references of the or banded), Haas (bonded or banded), Quad Helix excluded full-text). The most common exclusion crite- (QH), Minne-expander, bone-anchored maxillary rion was the absence of a systematic search strategy. expander, Nitanium maxillary expander and Fig. 1. PRISMA Flow Diagram. © 2016 John Wiley & Sons Ltd  Table 3. Data extracted from the 12 SRs and MAs included Intervention Study design, (I) or Appliance Author’s Conclusion (A) and Author, year, total no of (A) and control Expansion Outcome Methods/ Quality of the Author’s Comments on the © 2016 John Wiley & Sons Ltd reference subjects Diagnosis groups (C) Technique measures Measurement primary studies Results Quality of the Papers (Q) Schiffman & Meta-Analysis Unilateral or I1: Hyrax SME and Long-term NR Self-produced The mean expansion was A: Maxillary expansion stability Tuncay, 2001 of 2 RCTs, bilateral I2: QH RME skeletal meta-analytic 6
00 mm  1
29. While wearing is minimal. Post-retention data (21) 2 P CCTs and posterior C: Absent/AT transversal score: unclear retention in the short-term (1 yr.), the 92% of the Q: NR original expansion was maintained. Post- retention data show a total loss of 35
5% of the original transverse increase. Studies reporting short-term post- expansion data maintained 75% (3
88 mm), while longer term post- expansion data (>50 months) demonstrated a mean loss of 40% of the expansion (residual expansion 2
4 mm). I1 shows the 50% of relapse, while I2 around 64%. Petren Systematic Review Primary and I1: QH Unclear Dental Dental cast, Self-produced 100% or close to 100% of success rate A: QH and RME are effective in et al., 2003* of 2 RCTs, 5 P early mixed I2: RME effects (of posteroanterior checklist: 8 when using I1 or I2. Spontaneous the early mixed dentition at a (22) CCTs, 5 R CCTs† dentition with (Hyrax/Haas) the early radiographs, low quality, correction was found to occur in 16% to high success rate. However, 695 subjects posterior C: UCG/AT treatment) lateral 4 medium 50% of the untreated control groups. there is no scientific evidence crossbite radiographs, quality Highest amount of correction with I1 available that shows which of Clinical (Mmw: from 3
3-to 6
4 mm and Mcw the treatment modalities is the Examination, from 1
3-to 5
2 mm), followed by I2 most effective. There is limited Photos (Mmw 5
5 mm, Mcw 3
2 mm). evidence for stability of Regarding stability after retention, higher crossbite correction at least values with I2 (Mmw: 5
4 mm, Mcw: 3 years post-treatment. 3
3 mm) followed by I1 (Mmw: from Q: Primary studies lack of 3
6-to 5
1 mm Mcw: from 2
2- to power because of small sample 3
3 mm) size, bias, and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods EVIDENCE FROM SRS ON PALATAL EXPANSION 547  548 Table 3. (continued) Intervention Study design, (I) or Appliance Author’s Conclusion (A) and Author, year, total no of (A) and control Expansion Outcome Methods/ Quality of the Author’s Comments on the R. B U C C I et al. reference subjects Diagnosis groups (C) Technique measures Measurement primary studies Results Quality of the Papers (Q) Lagravere Systematic Review NR I1: Type of RME Long-term Posteroanterior Self-produced Transverse changes: Statistical increase of A: Long-term stability of et al., 2005 of 3 R CCTs; appliance NR skeletal radiographs, checklist:2 latero-nasal width. Statistically significant transverse skeletal maxillary (10) 113 subjects C: UCG/fixed transversal, lateral low (50% of checks) difference term transverse skeletal Vertical changes: A statistically significant maxillary increase is long-term difference was present in the approximately 25% of the total SN-PP (0
88°) and SN-Gn (0
88°) angles appliance adjustment (dental when comparing RME vs. C. Mandibular expansion) in pre-pubertal plane reduction ( 0
85°) was lower than adolescents but not significant that reported in C. for post-pubertal adolescents. RME did not produce significant anteroposterior or vertical changes. Q: Lack of description of a statistical estimation process for the sample size, dropouts, and intra- and inter-examiner reliability. Long-term RCTs are required. Lagravere Systematic Review Unilateral I1: Haas RME Long-term dental Dental cast, NR I1 increases Mmw (between 4
8-and A: Clinically significant long-term et al., 2005 of 3 R CCTs and bilateral (+fixed effects (Mmw; posteroanterior 2
7-mm), Mpw (between 4
7-and maxillary molar width increase (23) and 1 P CCT; posterior treatment) Mpw; Mcw; radiographs, 3
7-mm) and Mcw (between 2
5- and can be achieved with I1. 412 subjects crossbite C: UCG mmw; mcw; lateral 2
2-mm) and mmw (between 5
4- and Because of crown tipping, the OVJ; molar radiographs 0
7-mm) and mcw (between 1
8- and amount of reported long-term extrusion; 0
8-mm) width increase varied with the incisor I1 decreases OVJ (0
6 mm), while no reference point used for inclination statistically significant difference was measurements. More transverse and OVB). found for molar extrusion, incisor dental arch changes were found inclination and OVB when compared after puberty compared with with C. before puberty. The difference may not be clinical significant (0
8 mm). No anteroposterior or vertical dental changes were associated with RME with Haas expander. Q: Lack of clear statement regarding the retention protocol and different landmarks for measurements. © 2016 John Wiley & Sons Ltd  Table 3. (continued) Intervention Study design, (I) or Appliance Author’s Conclusion (A) and Author, year, total no of (A) and control Expansion Outcome Methods/ Quality of the Author’s Comments on the reference subjects Diagnosis groups (C) Technique measures Measurement primary studies Results Quality of the Papers (Q) Lagravere Systematic Constricted I1: Minne- SME Skeletal and Dental cast, NR I1 increase the transversal width, with a A: No strong conclusion can be et al., Review of 1 RCT, arches expander dental effects posteroanterior skeletal response from the 28 to the made on dental or skeletal 2005 (24) 4 P CTs and (banded or radiographs, 50% of the total expansion. No changes after SME. 4 non-controlled bonded) lateral difference between bonded and Q: Absence of untreated control CTs; I2: QH radiographs banded I1. group for all of the included © 2016 John Wiley & Sons Ltd 89 subjects I3: Nitanium I2 can determine a small percentage of studies maxillary skeletal expansion, but the major effect expander is dentoalveolar. More skeletal effects are C: absent/AT obtained in younger patients. I3 effects similar to those of I1. Lagravere et al., Meta-Analysis of NR I1: Hyrax RME Immediate Dental cast, Self-produced Transverse dental changes. Increase of A: The greatest changes were in 2006 (25) 2 RCTs; 9 P CCTs (with or transversal posteroanterior checklist: 14 Mmw (from 6
04- to 6
74-mm), the maxillary transverse plane and 3 without anteroposterior radiographs, low (