Dental and skeletal effects of palatal expansion techniques: a systematic review of the current evidence from systematic reviews and meta‐analyses

Abstract

The aim was to assess the quality and to summarise the findings of the Systematic Reviews (SRs) and Meta-Analyses (MAs) on the dental and skeletal effects of maxillary expansion. Electronic and manual searches have been independently conducted by two investigators, up to February 2015. SRs and MAs on the dentoalveolar and skeletal effects of fixed expanders were included. The methodological quality was assessed using the AMSTAR (A Measurement Tool to Assess Systematic Reviews). The design of the primary studies included in each SR/MA was assessed with the LRD (Level of Research Design scoring). The evidence for each outcome was rated applying a pre-determined scale. Twelve SRs/MAs were included. The AMSTAR scores ranged from 4 to 10. Two SRs/MAs included only RCTs. The current findings from SRs/MAs support with high evidence a significant increase in the short-term of maxillary dentoalveolar transversal dimensions after Rapid Maxillary Expansion (RME). The same effect is reported with moderate evidence after Slow Maxillary Expansion (SME). However, there is moderate evidence of a non-significant difference between the two expansion modalities concerning the short-term dentoalveolar effects. With both RME and SME, significant increase of skeletal transversal dimension in the short-term is reported, and the skeletal expansion is always smaller than the dentoalveolar. Even though dental relapse to some extent is present, long-term results of the dentoalveolar effects show an increase of the transversal dimension, supported by moderate evidence for RME and low evidence for SME. Skeletal long-term effects are reported only with RME, supported by very low evidence.

Skeletal and dental effects of Class III orthopaedic treatment: a systematic review and meta‐analysis

“…Even though the SMD decreases the possible discrepancies in terms of magnification, variables assessed and study method error, interpretation by clinicians is difficult. Moreover, the inclusion of non‐randomised studies could be considered a limit , but it was supported to provide a wider overview on this topic.…”

Effects of maxillary expansion on the upper airways: Evidence from systematic reviews and meta‐analyses

“…Maxillary expansion (ME) is an effective routine clinical orthodontic treatment for skeletal transversal maxillary constriction in young patients, aiming to open the mid‐palatal suture and to lateral displace the maxillary bones . Although this therapy is commonly carried out to correct dental and skeletal maxillary transverse discrepancies, some investigators have shown that treatment outcomes could also include favourable effects on the nasopharyngeal airways …”

Digital evaluation of nasal changes induced by rapid maxillary expansion with different anchorage and appliance design

“…The effects of RME on craniofacial structures have been extensively studied in the literature [1, 2] and are referred not only to anatomical structures close to the maxillary bone, but also to cranial base and temporomandibular joint [3]. Several authors suggested that RME affected the whole naso-maxillary complex, increasing nasal width and volume, also reducing the resistance of nasal airflow [4–6].…”

“…Several authors suggested that RME affected the whole naso-maxillary complex, increasing nasal width and volume, also reducing the resistance of nasal airflow [4–6]. However, scientific evidence does not seem to recommend RME for the sole purpose of restoring the respiratory function [1]. RME is achievable by means of various appliances and treatment protocols, including the most recently developed bone-anchored expansion [7, 8].…”