Comparison between two screws for maxillary expansion: a multicenter randomized controlled trial on patient's reported outcome measures

Three-dimensional assessment on digital cast of spontaneous upper first molar distorotation after Ni-ti leaf springs expander and rapid maxillary expander: A two-centre randomized controlled trial

OBJECTIVE

The aim of this randomized controlled trial (RCT) was to evaluate the spontaneous distorotation of upper first permanent molars and the transverse dentoalveolar changes on digital casts in growing patients following maxillary expansion treatment using either the Leaf Expander® or the rapid maxillary expander (RME), both anchored to the deciduous second molar.

TRIAL DESIGN AND SETTING

This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy.

PARTICIPANTS

Inclusion criteria included maxillary transverse deficiency, prepubertal development stage (cervical vertebra maturation stage [CVMS] 1-2) and early mixed dentition with fully erupted upper first permanent molars. Exclusion criteria were systemic diseases or syndromes, CVMS 3-6, agenesis of upper second premolars, unavailability of the second deciduous molar for anchorage and Class III malocclusion.

RANDOMIZATION

Patients were randomly assigned to the Leaf Expander® or RME group using a computer-generated randomization list created by a central randomization centre. Randomization was conducted immediately before the start of treatment.

INTERVENTION

The intervention involved treatment with either the Leaf Expander® or the RME. Both devices were anchored to the second deciduous molars. Following randomization, patients were further categorized based on the presence of no crossbite, unilateral crossbite or bilateral crossbite.

MAIN OUTCOME MEASURE

The primary outcome measure was the distorotation of the upper first molar (U6). Secondary outcomes included measurements of interdental linear dimensions, specifically upper inter-canine width (53-63), upper inter-molar width (MV16-MV26) and upper inter-deciduous second molar width (55-65).

BLINDING

The examiner analysing the digital casts was blinded to the treatment groups to prevent detection bias and ensure objective assessment. However, due to the nature of the intervention, blinding was not feasible for the patients and clinicians involved in administering the treatment.

RESULTS

A total of 150 patients were enrolled and randomly assigned to two groups: 75 to the Leaf Expander® group and 75 to the RME group. Recruitment started in November 2021 and was completed in November 2022. At the time of analysis, the trial was complete with no ongoing follow-ups. ANOVA tests revealed no significant differences between the three subgroups (no-cross, unilateral-cross and bilateral-cross) within both the Leaf Expander® and RME groups at T0. The Leaf Expander® demonstrated significantly greater distorotation in the unilateral crossbite subgroup compared to the RME (p = .014). In terms of total molar distorotation, the Leaf Expander® appliance showed a significantly greater effect (12.66°) compared with conventional RME (7.83°). Linear regression analysis demonstrated a significant correlation between the extent of expansion and the degree of molar rotation.

CONCLUSIONS

Maxillary expansion resulted in significant spontaneous molar distorotation when the appliance was bonded to the second deciduous molars. The Leaf Expander® exhibited significantly greater molar distorotation compared with conventional RME. The degree of molar distorotation was correlated with the extent of expansion obtained on the second deciduous molar.

TRIAL REGISTRATION

The trial was registered at ClinicalTrials.gov (ID: NCT05135962).

Spontaneous Mandibular Dentoalveolar Changes after Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander-A Systematic Review

BACKGROUND

This systematic review aims to analyze the spontaneous dentoalveolar changes in the mandibular arch after maxillary expansion in growing patients obtained with different expansion protocols: Rapid Maxillary Expansion (RME), Slow Maxillary Expansion (SME), and Leaf Expander.

METHODS

The study adhered to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. Eligibility criteria were established in the PICO format, involving patients who underwent slow, rapid, or leaf maxillary expansion during the mixed or early permanent dentitions. A comprehensive search of electronic databases and manual searches was conducted up to December 2023. The outcome measures included inter-mandibular first permanent molar width, inter-deciduous molar and canine width, arch perimeter, and arch length; both short- and long-term results were considered. The articles that met the inclusion criteria were included in this systematic review and were qualitatively evaluated using a methodological quality scoring system with a 13-point scale. To assess the inter-examiner agreement concerning the article selection and the qualitative assessment of the included studies, Kappa statistics were computed.

RESULTS

A total of 1184 articles were identified through electronic and manual searches. After the removal of duplicates and the initial examination of the titles and abstracts, 57 articles were considered for the full text analysis, and according to the eligibility and exclusion criteria, 22 studies were finally selected, composed of 8 randomized controlled trials (RCTs) and 14 retrospective/case-control studies. The qualitative assessment of the included studies showed the following scores: 6 papers have high research quality, 5 have moderate quality, and 11 have low quality. SME demonstrated negligible mandibular changes, with less than 1 mm variation on average (range 0.46-2.00 mm) in the selected parameters and relapses observed in the long term. RME induced more significant increases, particularly in intermolar width greater than 1 mm, which ranged between 0.93 and 3.3 mm, and good stability over the long term. Leaf Expander exhibited promising short-term lower intermolar width increases greater than 1 mm and ranged from 0.5 to 1.69 mm, but long-term stability was not thoroughly evaluated.

CONCLUSIONS

SME results in negligible short- and long-term effects, while RME, especially with Haas-type appliances, exhibits significant intermolar width increases that remain stable over the years. Leaf Expander shows short-term lower intermolar width increases, requiring further investigation into long-term stability.

Comparison of the skeletal, dentoalveolar, and periodontal changes after Ni-Ti leaf spring expander and rapid maxillary expansion: a three-dimensional CBCT based evaluation

BACKGROUND

The aim of the present study was twofold:(1) three-dimensionally evaluate the quantitative skeletal and dentoalveolar changes after Ni-Ti leaf spring expander (leaf expander) and rapid maxillary expansion (RME) in mixed dentition patients;(2) analyze the modifications of the buccal alveolar bone plate of the maxillary first permanent molars.

METHODS

Patients who underwent CBCT scans before and after maxillary expansion were randomly selected from the records archived at the Department of Biomedical Surgical and Dental Sciences, University of Milan, Italy. Inclusion criteria were the following: no systemic disease or syndromes; maxillary transverse deficiencies (difference between the upper intermolar width and the lower intermolar width of at least 3 mm and/or clinical need based on radiographic evaluation), early mixed dentition with ages between 7 to 10 years old; cervical vertebra maturation stage (CVMS) 1 or 2; no pathologic periodontal status; skeletal class I or II; maxillary expander cemented on the upper second deciduous molars. Exclusion criteria were the following: patients with pubertal or post-pubertal stage of development (CVMS 3-6); late deciduous or late mixed dentition, impossibility to use the second primary molar as anchorage; skeletal class III malocclusion; craniofacial syndromes; patients unable to be followed during the treatment period. Twenty-three patients treated with Leaf Expander, 11 males (mean age 7.8 ± 0.6 years) and 12 females (mean age 8.1 ± 0.8 years), met the inclusion criteria and constituted the case group. Twenty-four (control group) treated with conventional RME, 12 males (mean age 8.4 ± 0.9 years) and 12 females (mean age 8.1 ± 0.7 years). The paired-sample T test was used for intra-group comparison to evaluate the difference between before (T1) and after (T2) maxillary expansion. Independent sample t-test was computed to perform between groups comparison of the skeletal, dentoalveolar, and periodontal changes.

RESULTS

The Leaf Expander and RME group showed a significant increase between T1 and T2 for most of the skeletal and dentoalveolar variables. Concerning the skeletal variables only the RME demonstrated a significant increase at the level of the posterior nasal (PNW) and apical base width (PABW) and maxillary mid-alveolar width (MMW). Despite this, when compare with the Leaf Expander, the RME group exhibited a statistically larger width increase for only two skeletal parameters: PNW (p = 0.03) and MMW (p = 0.02). No significant changes at the periodontal level were found in either group.

CONCLUSIONS

According to the current research, the authors confirm the effectiveness of the Leaf Expander and RME to produce similar skeletal and dentoalveolar effects in mixed dentition subjects. Moreover, the devices anchored to deciduous teeth did not reduce the thickness and height of the buccal bone at the level of the maxillary permanent first molars in either of the two groups.

Comparison of Different Types of Palatal Expanders: Scoping Review

Maxillary bone contraction is caused by genetics or ambiental factors and is often accompanied by dental crowding, with the possibility of canine inclusion, crossbite, class II and III malocclusion, temporomandibular joint disorder, and obstructive sleep apnea (OSAS). Transverse maxillary deficits, in which the maxillary growth is unusually modest, are frequently treated with maxillary expansion. The purpose of this study is to compare the dental and skeletal effects of different types of expanders, particularly the Leaf Expander, rapid and slow dental-anchored or skeletal-anchored maxillary expanders.

METHODS

We chose studies that compared effects determined by palatal expansion using a rapid palatal expander, expander on palatal screws, and leaf expander.

RESULTS

Reports assessed for eligibility are 26 and the reports excluded were 11. A final number of 15 studies were included in the review for qualitative analysis.

CONCLUSIONS

Clinically and radiographically, the outcomes are similar to those obtained with RME and SME appliances; Therefore, it might be a useful treatment choice as an alternative to RME/SME equipment in cases of poor patient compliance or specific situations. Finally, all of the devices studied produce meaningful skeletal growth of the palate. The use of skeletally anchored devices does, without a doubt, promote larger and more successful growth in adolescent patients.

Self-perceived pain in Hyrax versus other maxillary expansion orthodontic appliances: a systematic review of clinical studies

PURPOSE

To evaluate self-perceived pain levels in the Hyrax compared to other types of maxillary expansion (ME) appliances in growing patients.

METHODS

An unrestricted search of indexed databases and manual searching were performed up to October 2022. Randomized controlled trials (RCTs) comparing the Hyrax appliance with other ME appliances were included. Data screening, extraction, and Risk of Bias (RoB) assessment with the Cochrane tool were performed by two authors.

RESULTS

Six RCTs were included. The number of participants in the included RCTs ranged between 34 to 114 and included both male and female growing patients. Various tools were used to measure self-perceived pain including the Graphic Rating Scale for Pain, the Wong-Baker Faces Pain Scale, the Numerical Rating Scale, the visual analogue scale, and a questionnaire. One RCT reported that pain intensity in patients treated with the Hyrax was higher than in the Haas appliance, with a statistically significant difference limited to the first day. Two RCTs reported that pain intensity in patients treated with the Leaf expander was lower than in the Hyrax during the first 7 days of treatment. Two RCTs reported no significant differences in pain intensity between the Hyrax and other ME appliances. One RCT reported that pain intensity in patients using the computer-guided skeletal ME appliance was higher than in the Hyrax appliance at the first day after expansion. Four RCTs had a high RoB, and two RCTs had a moderate RoB.

CONCLUSIONS

Within the limitations of the present systematic review and based on the currently available evidence, it is challenging and inconclusive to identify the best maxillary expansion appliances, regarding pain levels for growing patients.

Pain during Rapid Maxillary Expansion: A Systematic Review

Aim: The aim of the present systematic review is to evaluate the pain perceived by patients during rapid maxillary expansion (RME) in relation to factors such as demographic characteristics, appliance type, activation protocol, and the eventual use of medication or pain management strategies. Materials and methods: An electronic search of available articles on the subject was conducted on three electronic databases, using predefined keywords. Sequential screenings based on pre-established eligibility criteria were performed. Results: Ten studies were ultimately included in this systematic review. The main data of the reviewed studies were extracted according to the PICOS approach. Conclusions: Pain is a common effect of RME treatment that tends to decrease over time. Gender and age differences in pain perception are not clear. Perceived pain is influenced by the expander design and expansion protocol used. Some pain management strategies can be useful for reducing RME-associated pain.

Comparison of rapid versus slow maxillary expansion on patient-reported outcome measures in growing patients: a systematic review and meta-analysis

BACKGROUND

No systematic review and meta-analysis are present in the literature comparing patient-reported outcome measures (PROMs) in rapid maxillary expansion (RME) versus slow maxillary expansion (SME) in growing patients.

OBJECTIVE

The objective of this systematic review was to compare PROMs in RME versus SME in growing patients.

MATERIALS AND METHODS

Electronic search in PubMed (MEDLINE), Cochrane Library, Scopus, Embase, Web of Science, and OpenGrey was conducted. Only RCTs were included. Inclusion criteria were: growing patients in the mixed dentition or early permanent dentition, mild-to-moderate maxillary transverse deficiency, dental crowding, treatment with fixed expanders for rapid and slow maxillary expansion. Risk of bias was assessed using RoB 2. GRADE statement was performed. The mean of the differences (MD) and the risk ratio (RR) were used for the aggregation of data. A random effect model was applied.

RESULTS

Two articles with a total of 157 patients were finally included in the systematic review and meta-analysis. One article was at low risk of bias, while one was at risk of bias with some concerns. Pain presence was less, though not statistically significant, in SME patients (RR = 2.02, 95%CI from 0.55 to 7.49, P = 0.29, I² = 95%, 2 studies, GRADE very low). Pain intensity was significantly lower in SME appliance in the first week of treatment (pooled MD = 0.86 favoring SME, 95%CI from 0.47 to 1.26, P < 0.0001, I² = 6%, 2 studies, GRADE moderate). There were no significant differences between the two groups in difficulty in speaking, difficulty in swallowing, hypersalivation, difficulty in hygiene, and patient and parent satisfaction.

CONCLUSIONS

Pain intensity was significantly lower in SME compared to RME during the first week of treatment. For the following weeks, there were no differences in pain between the two protocols.

Hyrax versus Leaf expander in growing patients, what about adverse dental effects? A retrospective study

OBJECTIVES

Transverse discrepancy is a Common problem in young patients. Many devices are employed to expand the palatal dimension, with different characteristics and biomechanical aspects. The Leaf expander, a new-born appliance containing nickel-titanium springs, free from activation by parents. We compared the maxillary and mandibular dental effects of Leaf expander to conventional Hyrax in growing patients.

METHODS

All patients who met the eligibility criteria between the period from January 2017 to December 2019 were included. The patients had transverse inter-arch discrepancy of at least 5mm and were treated with Hyrax expander (HEX) or Leaf expander (LEX). All patients had complete follow-up of expansion by remote monitoring. An algorithm established distances between the teeth. It was also used to measure the change in dental axes.

RESULTS

In the maxilla, LEX caused more tipping on the canines and premolars but significantly less on the molars compared to HEX: -0.154̊ vs. 3.05̊ (P<0.001). In the mandible, LEX caused a greater increase in arch widths and tipping (P<0.02) in the molars and second premolars, but not in the other teeth. No correlation was demonstrated between mandibular dental movements and increased maxillary arch widths. Alternatively, for the two devices, expansion and tipping were correlated within each dental arch (r>0.4).

CONCLUSIONS

The LEX produced more tooth movement on average than the HEX, except for the maxillary first molars. Several correlations exist between the movements within each arch for the two devices, most often between tipping and expansion.

Orthodontic treatment for posterior crossbites

BACKGROUND

A posterior crossbite occurs when the top back teeth bite inside the bottom back teeth. The prevalence of posterior crossbite is around 4% and 17% of children and adolescents in Europe and America, respectively. Several treatments have been recommended to correct this problem, which is related to such dental issues as tooth attrition, abnormal development of the jaws, joint problems, and imbalanced facial appearance. Treatments involve expanding the upper jaw with an orthodontic appliance, which can be fixed (e.g. quad-helix) or removable (e.g. expansion plate). This is the third update of a Cochrane review first published in 2001.

OBJECTIVES

To assess the effects of different orthodontic treatments for posterior crossbites.

SEARCH METHODS

Cochrane Oral Health's Information Specialist searched four bibliographic databases up to 8 April 2021 and used additional search methods to identify published, unpublished and ongoing studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of orthodontic treatment for posterior crossbites in children and adults.

DATA COLLECTION AND ANALYSIS

Two review authors, independently and in duplicate, screened the results of the electronic searches, extracted data, and assessed the risk of bias of the included studies. A third review author participated to resolve disagreements. We used risk ratios (RR) and 95% confidence intervals (CIs) to summarise dichotomous data (event), unless there were zero values in trial arms, in which case we used odds ratios (ORs). We used mean differences (MD) with 95% CIs to summarise continuous data. We performed meta-analyses using fixed-effect models. We used the GRADE approach to assess the certainty of the evidence for the main outcomes.

MAIN RESULTS

We included 31 studies that randomised approximately 1410 participants. Eight studies were at low risk of bias, 15 were at high risk of bias, and eight were unclear. Intervention versus observation For children (age 7 to 11 years), quad-helix was beneficial for posterior crossbite correction compared to observation (OR 50.59, 95% CI 26.77 to 95.60; 3 studies, 149 participants; high-certainty evidence) and resulted in higher final inter-molar distances (MD 4.71 mm, 95% CI 4.31 to 5.10; 3 studies, 146 participants; moderate-certainty evidence). For children, expansion plates were also beneficial for posterior crossbite correction compared to observation (OR 25.26, 95% CI 13.08 to 48.77; 3 studies, 148 participants; high-certainty evidence) and resulted in higher final inter-molar distances (MD 3.30 mm, 95% CI 2.88 to 3.73; 3 studies, 145 participants, 3 studies; moderate-certainty evidence). In addition, expansion plates resulted in higher inter-canine distances (MD 2.59 mm, 95% CI 2.18 to 3.01; 3 studies, 145 participants; moderate-certainty evidence). The use of Hyrax is probably effective for correcting posterior crossbite compared to observation (OR 48.02, 95% CI 21.58 to 106.87; 93 participants, 3 studies; moderate-certainty evidence). Two of the studies focused on adolescents (age 12 to 16 years) and found that Hyrax increased the inter-molar distance compared with observation (MD 5.80, 95% CI 5.15 to 6.45; 2 studies, 72 participants; moderate-certainty evidence). Intervention A versus intervention B When comparing quad-helix with expansion plates in children, quad-helix was more effective for posterior crossbite correction (RR 1.29, 95% CI 1.13 to 1.46; 3 studies, 151 participants; moderate-certainty evidence), final inter-molar distance (MD 1.48 mm, 95% CI 0.91 mm to 2.04 mm; 3 studies, 151 participants; high-certainty evidence), inter-canine distance (0.59 mm higher (95% CI 0.09 mm  to 1.08 mm; 3 studies, 151 participants; low-certainty evidence) and length of treatment (MD -3.15 months, 95% CI -4.04 to -2.25; 3 studies, 148 participants; moderate-certainty evidence). There was no evidence of a difference between Hyrax and Haas for posterior crossbite correction (RR 1.05, 95% CI 0.94 to 1.18; 3 studies, 83 participants; moderate-certainty evidence) or inter-molar distance (MD -0.15 mm, 95% CI -0.86 mm to 0.56 mm; 2 studies of adolescents, 46 participants; moderate-certainty evidence). There was no evidence of a difference between Hyrax and tooth-bone-borne expansion for crossbite correction (RR 1.02, 95% CI 0.92 to 1.12; I² = 0%; 3 studies, 120 participants; low-certainty evidence) or inter-molar distance (MD -0.66 mm, 95% CI -1.36 mm to 0.04 mm; I² = 0%; 2 studies, 65 participants; low-certainty evidence).  There was no evidence of a difference between Hyrax with bone-borne expansion for posterior crossbite correction (RR 1.00, 95% CI 0.94 to 1.07; I² = 0%; 2 studies of adolescents, 81 participants; low-certainty evidence) or inter-molar distance (MD -0.14 mm, 95% CI -0.85 mm to 0.57 mm; I² = 0%; 2 studies, 81 participants; low-certainty evidence).  AUTHORS' CONCLUSIONS: For children in the early mixed dentition stage (age 7 to 11 years old), quad-helix and expansion plates are more beneficial than no treatment for correcting posterior crossbites. Expansion plates also increase the inter-canine distance. Quad-helix is more effective than expansion plates for correcting posterior crossbite and increasing inter-molar distance. Treatment duration is shorter with quad-helix than expansion plates. For adolescents in permanent dentition (age 12 to 16 years old), Hyrax and Haas are similar for posterior crossbite correction and increasing the inter-molar distance. The remaining evidence was insufficient to draw any robust conclusions for the efficacy of posterior crossbite correction.

Dento-skeletal effects produced by rapid versus slow maxillary expansion using fixed jackscrew expanders: a systematic review and meta-analysis

BACKGROUND

No systematic review and meta-analysis of dento-skeletal effects following rapid maxillary expansion (RME) and slow maxillary expansion (SME) using the same jackscrew expander with different activation protocols is available.

OBJECTIVE

To compare dento-skeletal effects produced by RME with those induced by SME using the same fixed jackscrew expanders in growing patients.

SEARCH METHODS

PubMed (MEDLINE), Cochrane Library, Scopus, Embase, and OpenGrey were searched with no language or publication date restrictions.

SELECTION CRITERIA

Only randomized controlled trials (RCTs) were selected and the following inclusion criteria were used: growing patients in mixed or permanent dentition, with maxillary transverse discrepancy, dental crowding, and treated with fixed jackscrew maxillary expander (e.g. Hyrax, Haas) activated to achieve either RME or SME.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers. The quality of the included RCTs was assessed according to the Cochrane risk-of-bias tool for randomized trials (RoB 2.0). For the aggregation of continuous data, the mean of the differences (MD) between treatments was used. A random effect model was applied.

RESULTS

From 4855 retrieved articles, 3 studies were selected, 1 at unclear risk and 2 at high risk of bias. Maxillary intermolar distance showed no significant differences between the two modalities of expansion [pooled MD = 0.99 mm favouring RME, with 95% confidence interval (CI) = -2.09 to 4.06, P = 0.53, I2 = 90%]. As for maxillary molar inclination measured as the angle formed by the axes passing through the disto-buccal cusps and the apexes of the palatine root of the first upper molars, it was significantly smaller in the SME group (MD = -11.51°, with 95% CI = -15.23 to -7.79, P < 0.0001). Posterior maxillary expansion was significantly greater in RME than SME (pooled MD = 0.75 mm, with 95% CI = 0.27-1.23, P = 0.002, I2 = 0%).

CONCLUSIONS

Both RME and SME produce an effective dento-skeletal expansion of the maxilla. RME is slightly more effective in increasing the posterior transverse skeletal width of the maxilla while SME induces smaller molar inclination.

REGISTRATION

PROSPERO CDR42018105530.

Evaluation of self-perceived pain and jaw function impairment in children undergoing slow and rapid maxillary expansion: A prospective clinical trial

OBJECTIVES

To evaluate and compare perceived pain and jaw function impairment during the first 4 weeks with slow maxillary expansion (SME) using quadhelix and rapid maxillary expansion (RME) using conventional banded hyrax.

MATERIALS AND METHODS

Sixty patients aged 10.2 to 15 years were enrolled and consecutively recruited to either the quadhelix group (QG) or hyrax group (HG). A questionnaire was used to evaluate pain, jaw function impairment, and analgesic consumption in the first 7 days, at 2 weeks, and at 4 weeks.

RESULTS

Fifty-five patients (43 girls and 12 boys) completed the questionnaire at all time points (27 in the QG and 28 in the HG). Except at 4 hours, there were no significant differences between the groups regarding pain from teeth, tongue, and palate. Patients started to adapt after day 3. Patients in the HG group reported significantly higher scores for difficulty in swallowing (moderate to severe) during the first 6 days. In both groups, minimal effects were found on speech and the majority of patients did not experience difficulty in yawning or laughing. There was no significant difference in analgesic consumption between the groups. No correlations were found between age, gender, or malocclusion type and any of the investigated outcomes.

CONCLUSIONS

Quadhelix for SME and conventional banded hyrax for RME were well tolerated by patients after 1 week. The decision to use either appliance could be based on factors not related to patient experiences.