Rapid Maxillary Expansion Research Articles

Effect of rapid maxillary expansion on nasomaxillary structure and sleep disordered breathing in children with obstructive sleep apnoea.

The aim of this study was to assess the effect of RME on upper airway structure and its relationship to improvements in sleep disordered breathing. The study was carried out in 23 children with malocclusion and OSA. Clinical assessment visits, daytime sleepiness questionnaire, polysomnography and orthognatodontic examination were performed before (T0) and 4 (T1) and 12 (T2) months after RME. CB CT scans with 2D and 3D reconstructions were performed before (T0) and 12 after months (T2) RME. The relationship between airway changes and improvements in sleep disordered breathing were evaluated. In all cases, opening of the mid-palatal suture was successfully achieved. Volume of the total upper airways, nasal cavity, nasopharynx and oropharynx increased significantly as well as the nasal osseous width. The increase in posterior suture, pterygoid process, maxillary, nasal cross-sectional width were significantly correlated with total upper airway volume, nasal cavity volume, nasopharyngeal airway volume, and oropharyngeal airway volume. The improvement in AHI was correlated with the increase in total upper airway volume at 12 months. The study provides important details about the effect of RME on upper airway structure, including an enlarged posterior suture, pterygoid process, maxillary width and nasal cross-sectional width and enlarged airway volume.

Anchorage In Primary Vs. Permanent Teeth For Rapid Maxillary Expansion In Children: Systematic Review And Meta-Analysis

Background: Rapid maxillary expansion (RME) is a widely used orthodontic technique to correct transverse maxillary deficiencies. Both primary and permanent teeth are commonly used as anchorage for this procedure. However, there is limited evidence regarding differences in skeletal and dental effects or buccal alveolar bone preservation between these anchorage types. Materials and Methods: A systematic review was conducted to compare the skeletal and dental effects of RME using primary or permanent teeth as anchorage. Searches were performed in the following databases: PubMed, Web of Science, Scopus, LILACS, and OpenGrey. The risk of bias was assessed using the Rob 2.0 and Robins I tools. The certainty of evidence was evaluated according to the GRADE system, and meta-analysis was performed with R software. Results: Eight studies were included in the qualitative analysis and five in the quantitative analysis. The risk of bias was low in two studies, moderate in five studies, and high in one study. The certainty of evidence was very low. It was not possible to perform a meta-analysis for the outcome "buccal alveolar bone thickness" due to the lack of available studies, which was limited to only one study. The intermolar width was greater when the anchorage used permanent teeth SMD= -1.24; 95% CI (-2.14; -0.33); p<0.01]. However, this difference may not be clinically relevant. Conclusion: The evidence does not support a clear recommendation for the use of primary or permanent teeth as anchorage in RME, as no clinically relevant differences were observed in skeletal or dental effects. Primary teeth may be preferred when buccal alveolar bone preservation is a priority. Further studies are required to enhance evidence and support clinical decisions.

Comparison of the effectiveness of skeletal and tooth-borne protraction methods with or without alternate rapid maxillary expansion and constriction protocol in patients with Class III malocclusion

Comparison of the effectiveness of skeletal and tooth-borne protraction methods with or without alternate rapid maxillary expansion and constriction protocol in patients with Class III malocclusion

Investigation of changes caused by Rapid Maxillary Expansion in mandibular bone and temporomandibular joint trabecular structure using fractal analysis

BackgroundThe aim of this study is to evaluate the changes in the trabecular structure of the mandibular bone and temporomandibular joint following Rapid Maxillary Expansion.MethodsThirty-nine patients who received Rapid Maxillary Expansion treatment in the Department of Orthodontics of the Faculty of Dentistry were selected from the archieve for the study. Trabecular structure changes of the angulus mandible, corpus mandible, and condyle regions were examined using fractal analysis on the dental panoramic radiographs. Radiographs taken before the treatment (T0) and at the end of the 3-month retention period (T1) of the patients.ResultsThere was no statistically significant difference between T0 and T1 in the condyle, ramus mandible, and corpus mandible regions depending on time and sex. (p < 0.05)ConclusionThe results of this study showed that Rapid Maxillary Expansion treatment does not have a significant impact on the trabecular structure of the mandible and temporomandibular joint depending on time and gender.

Evaluation of condylar dimension and position following rapid maxillary expansion with tooth- or tooth-bone-borne appliances.

To assess and compare changes in the dimension and position of the mandibular condyle after tooth-borne (Hyrax) and tooth-bone-borne (Hybrid Hyrax) expansion. Twenty-five patients who underwent expansion with either tooth-borne appliances (8 girls, 5 boys; mean age 14.3 ± 2.3 years) or tooth-bone-borne appliances (6 girls, 6 boys; mean age 13.8 ± 2.2 years) were examined. Condylar and glenoid fossa morphology before (T0) and 3 months after (T1) expansion were evaluated using cone-beam computed tomography. Condylar measurements (anterior, posterior, and superior joint spaces; condylar height, length, and width), along with sagittal and vertical skeletal and maxillary transversal measurements, were analyzed using Dolphin Imaging software. Wilcoxon and Paired t tests were used for T0 and T1 evaluations, and the Mann-Whitney U test for intergroup comparisons. At both T0 and T1, no statistically significant differences were observed between the groups in terms of condylar dimensions or the position of the condyle within the glenoid fossa. Maxillary transversal measurements increased after expansion in both groups (P < 0.01), with a significantly greater increase in first premolar width in the Hyrax group (P < 0.05). The vertical position of the posterior teeth showed no noteworthy changes (P > 0.05), except for the right second premolar. Temporomandibular joint measurements did not significantly change in either group after treatment (P > 0.05). Neither tooth-borne nor tooth-bone-borne expansion caused significant changes in the condylar dimensions and position at the end of treatment.

Surgical Assisted Rapid Maxillary Expansion in Hemifacial Syndrome Patient Post Primary Cleft Treatment: A Case Report

Introduction: Cleft lip and palate is a congenital malformation resulting from an incomplete or incorrect fusion during embryonic development. Hemifacial syndrome is one of rare orofacial anomalies with midface hypoplasia. Maxillomandibular deformity repair for maxillary hypoplasia can be achieved by repositioning the maxilla and mandible to correct occlusion, mastication, functional issues, cosmetic concerns, and facial symmetry. The main concerns in the case of maxillary hypoplasia are the repair of transverse (narrowing of the maxilla), sagittal (anterior posterior), and vertical (facial proportion) aspects. This study aimed to elucidate the treatment for patients with maxillary hypoplasia by utilizing the surgical assessment of rapid maxillary expansion (SARME) following cleft lip and palate surgery. Case Report: A 21-year-old female patient had symptoms of a truncated maxilla, compromised speech, and challenges with mastication and ingestion. The patient’s surgical history includes having undergone labioplasty, palatoplasty in 2002, and gnatoplasty in 2023. The recommended treatment for this situation involves SARME. The patient’s speaking and feeding difficulties were caused by both transversal and vertical problems in the patient with maxillary hypoplasia. This is why the therapy was necessary. Case Management: Implementation of surgical assessment rapid maxillary expansion (SARME). Conclusions: This case report concludes a notable improvement in the upper and lower jaw’s functional, masticatory, and aesthetic aspects in a patient with maxillary hypoplasia. This improvement was achieved with surgical assisted of rapid maxillary expansion (SARME) following primary cleft lip and palate surgery. Keywords: Cleft lip and palate, Hemifacial syndrome, SARME

3D printed customized facemask for early treatment of Class III malocclusion: a two-center case series feasibility study.

This prospective two-center case series feasibility study aimed to investigate the potential of a novel maxillary protraction facemask customized to the patients' anatomy recorded with 3D face scanning and then produced by digital design and additive manufacturing. Ten subjects (5 females and 5 males, average age 7.7±1.0 years) with Class III malocclusion were treated with a rapid maxillary expander (RME) and a Petit-type facemask (FM), whose components were digitally designed on a 3D scan of the patient's face. Subjects' face scans were obtained either with a tablet or with face scanner. FM components were modelled with a 3D software. The pads were 3D printed in biocompatible resin, and the bar was printed in stainless steel. A questionnaire investigating the patients' experience was filled in after the first week of treatment and after 3, 6, and 9 months. The customized FM showed an excellent adaptation to the anatomy of the face. No severe complications were reported during the 9 months of appliance wearing. Some reversible episodes of skin irritation were reported below the pads, mainly in the chin area. The reported time wearing ranged between 8.2±2.3 and 9.5±1.2 hours per day, mainly at night. Reported pain was overall low (maximum after 1 week with an average value of 1.9±1.7 on a visual analog scale [VAS] 0-10) and patients' satisfaction was adequate at the end of the facemask wear after 9 months (8.7±1.4 on a VAS 0-10). The customized FM was overall well accepted by the patients and represents a valid alternative to conventional ones.

A Comprehensive Literature Review On Alternative Rapid Maxillary Expansion &amp; Constriction Vs Conventional Rapid Maxillary Expansion Protocol In Protraction Facemask Therapy

The aim of this review article is to highlight the increasing popularity of Alt-RAMEC or Alternative Rapid Maxillary Expansion and Constriction procedure. It is a protocol used to correct the transverse maxillary discrepancy. In conjunction with facemask therapy, it can be used to correct the sagittal maxillary discrepancy in Class III malocclusion with a retrusive maxilla. Alt-RAMEC procedure was introduced by Liou in 2005 with the conclusion that the maxilla can be protracted more effectively through a repetitive weekly protocol of alternate expansion and constriction than with a single course of rapid maxillary expansion (RME). The article highlights the comparison of Alt-RAMEC maxillary expansion protocol with conventional RME protocol. This review will discuss the studies which include successful treatments by applying this protocol and differences with other methods.

An overview of treatment strategies for class II and class III malocclusions

Class II and class III malocclusions represent common yet complex dental conditions that affect both aesthetics and function. Managing these malocclusions requires an approach tailored to the patient's growth stage, with early interventions focusing on growth modification and adult cases often necessitating surgical solutions. In class II malocclusions, growth modification with functional appliances such as the Twin Block and Herbst appliance promotes mandibular advancement and improves facial harmony in younger patients. For older individuals or those with more severe malocclusions, orthodontic camouflage or mandibular advancement surgery, including bilateral sagittal split osteotomy, is recommended to achieve a balanced occlusal relationship and improve facial proportions. Class III malocclusions, often involving a prognathic mandible or maxillary deficiency, are particularly challenging. For young patients, facemask therapy and rapid maxillary expansion can encourage maxillary growth, while chin cup therapy can control mandibular projection, aiming to improve skeletal balance. In severe adult cases, combined orthodontic-surgical treatments, such as maxillary advancement through Le Fort I osteotomy or mandibular setback procedures, provide durable, functionally stable outcomes. Surgical-orthodontic approaches, including bimaxillary surgery, are particularly advantageous for severe class III cases by effectively addressing the underlying skeletal imbalances and enhancing facial aesthetics. Growth modification techniques emphasize the importance of early diagnosis and intervention, aiming to harness natural growth potential and reduce the need for more invasive treatments later in life. For adult patients, surgical interventions present a definitive solution, delivering substantial improvements in function and appearance. Ongoing advances in both orthodontic and surgical techniques are refining the precision and stability of treatment outcomes, underscoring the need for individualized, age-appropriate strategies in managing class II and class III malocclusions.

Evaluation of dimensional changes of the nasolacrimal canal after rapid maxillary expansion: A cone-beam computed tomography study

ObjectiveThe aim of this study is to evaluate the nasolacrimal canal dimensionally and volumetrically after treatment in patients who underwent rapid maxillary expansion. Materials and methodsA total of 19 patients (12 females, 7 males) with maxillary transverse deficiency, who underwent rapid maxillary expansion were included in the study. Cone beam computed tomography images were analyzed to measure the volume, anteroposterior diameter, transverse diameter, length, and angle of the nasolacrimal duct before and after treatment. ResultsThe average age of the patients was 13.8 ± 1.69 years. Statistically significant increases in the volume, anteroposterior diameter, transverse diameter, length, and angle of the nasolacrimal canal were observed after treatment for both the right and left sides. No significant difference was found nasolacrimal canal dimensionally and volumetrically except angle on the left and right side of male and female patients. No significant differences were found in the changes between male and female patients. ConclusionRapid maxillary expansion resulted in significant dimensional and volumetric increases in the nasolacrimal canal. Although no prior studies have linked maxillary transverse deficiency to nasolacrimal canal obstruction, the findings suggest that RME may be a viable treatment for nasolacrimal canal obstruction under appropriate conditions.

Effects of Hyrax Maxillary Expander on Nasal Cavity and Upper Airway in Adolescents: A Systematic Review and Meta-Analysis.

Whether Hyrax maxillary expander is an effective treatment for maxillary transverse deficiency as well as expansion of the upper airway is still controversial. The study's purpose was to evaluate 3D changes in upper airway dimensions of adolescent patients measured primarily by cone-beam computed tomography (CBCT) after rapid maxillary expansion (RME) with the Hyrax maxillary expander. Studies up to 1 April 2024 were searched in the following databases: PubMed/MEDICINE, Web of Science, Cochrane Library, and Embase. Inclusion criteria were clinical trials and cohort studies that assessed the effect of RME in adolescent patients with upper airway stenosis using CBCT-based three-dimensional analysis. The risk of bias in the study outcomes was assessed using the Cochrane Collaboration's risk of bias tool, the GRADE method, and a tool for evaluating non-randomized controlled study (non-RCT) literature from a previous systematic review, depending on the types of articles. The study was reported in accordance with PRISMA guidelines. The study conducted a random effects meta-analysis of mean differences and 95% confidence intervals for changes in upper airway volumes, including the nasal cavity (NC), in the outcomes of 16 included studies, followed by subgroup analyses. A significant increase in nasopharynx volume was observed after rapid maxillary expansion (RME) by Hyrax maxillary expander (MD = 0.69, 95% CI (0.09~1.28), p = 0.02).

Preadolescents’ Smile Outcomes after Two Different Orthodontic Treatments: Traditional Interceptive Therapy with Rapid Maxillary Expansion (RME)/Schwarz Plate and Clear Aligners

Preadolescents’ Smile Outcomes after Two Different Orthodontic Treatments: Traditional Interceptive Therapy with Rapid Maxillary Expansion (RME)/Schwarz Plate and Clear Aligners

Practices and Perception of Paediatric Obstructive Sleep Apnea Among Orthodontists and Paediatric Dentists in Brazil: A Mixed-Methods Study.

To explore orthodontists' (OTs) and paediatric dentists' (PDs) practices and perceptions regarding the screening and management of paediatric obstructive sleep apnea (OSA). This explanatory sequential mixed methods design included OTs and PDs with active clinical practice in Brazil and encompassed a quantitative phase followed by a qualitative phase. In the quantitative phase, a survey assessing OSA screening and management practices was administered to OTs and PDs practicing in Brazil. Information-rich OTs and PDs were interviewed in the qualitative phase. Descriptive statistics and the chi-square test were used to analyse the survey data, while inductive content analysis was applied to the interview data. The results from both phases were integrated and reported narratively. Three hundred eighty-one OTs and PDs completed the survey, and ten of them were interviewed. Nearly half of OTs and PDs administered sleep questionnaires and demonstrated some knowledge about paediatric OSA signs and symptoms. PDs and OTs primarily offered rapid maxillary expansion and functional mandibular advancement for managing selected children with OSA, with OTs being more frequently involved in this task than PDs. OTs and PDs identified several barriers and expressed the need for support regarding access to reliable screening tools and interprofessional care. Brazilian OTs and PDs were aware of the main signs and symptoms of paediatric OSA and were somewhat involved in offering oral appliance management options. To further define the role of these professionals, increasing support for dental professionals in OSA management and updating existing clinical guidelines is warranted.

Piezo1 Promotes Osteogenesis Through CaMKII Signalling in a Rat Maxillary Expansion Model.

Rapid maxillary expansion (RME) is a widely used technique to treat maxillary transverse deficiency. Piezo1 is a cation channel that is activated by mechanical force and regulates bone formation. This study aims to elucidate the role of Piezo1 in bone remodelling during the RME process. In this study, the periosteal-derived stem cells (PDSCs) were cultured and stretched by the Flexcell system. The effects of Piezo1 on osteogenesis were assessed via RNA sequencing, real-time quantitative PCR, and western blot analyses. Moreover, for invivo analyses, the rat RME model was established. The function of Piezo1 in mid-palatal suture bone remodelling was evaluated using micro-CT, haematoxylin-eosin (HE) staining, and immunohistochemistry analyses. It was revealed that under tension force, the osteogenic factors (Runt-related transcription factor 2, Osterix, and Alkaline Phosphatase) and Ca2+/calmodulin -dependent protein kinase (CaMKII) were significantly enhanced in PDSCs over time. Furthermore, these were also upregulated in the RME model with the expansion of the mid-palatal suture. However, Piezo1 inhibition by Grammostola spatulata mechanotoxin 4 downregulated the levels of these factors in the RME model. This study indicated that Piezo1 is associated with the osteogenesis of PDSCs and bone remodelling in the RME process. CaMKII might also participate in this process.

Nasal bone modification compared to normal growth after rapid maxillary expansion anchored onto deciduous teeth: a CBCT retrospective study.

The present study was designed to evaluate the enlargement of the nasal bone as side effect when a treatment with a Haas rapid maxillary expander is performed in early mixed dentition. The CBCT imaging of 36 children (mean age 8,4; SD,1,5) were retrospectively selected and then traced in order to evaluate the change in the nasal bone (primary outcome) and in the maxilla (secondary outcome). Five distances and one angle were measured: upper and lower nasal bone width (UNBw and LNBw) as well as its inclination (NBi), and the maxillary bone at the level of infraorbital foramen (IOFw), the nasolacrimal duct (NLDd), and greater palatine foramina (PFd). The sample was divided in a treatment group (26 subjects; 14 males; 12 females; mean age 8,0; SD 0,9), comprising children who underwent to a rapid maxillary expansion, and a control group (10 subjects; 7 males; 3 females; mean age 9,3; SD 2,3) including untreated children homogeneous for dental age to the treated subjects. Measurements were performed at baseline or before the treatment (T0), and after 2 years (T1). The transversal modification induced with a rapid maxillary expansion was limited to the maxilla without involving the nasal bones when the treatment was performed in early mixed dentition. The changes recorded in the nasal bones seem to be the same of what happens during normal growth.

Orthodontic-Surgically Assisted Rapid Maxillary Expansion In Skeletal Class-II Patient

Orthodontic-Surgically Assisted Rapid Maxillary Expansion In Skeletal Class-II Patient

Three dimensional radiological assessment of the mediopalatine suture ossification and its correlation with biological age and orthodontic anomaly

Introduction. Evaluating the ossification of the mediopalatine suture is crucial when considering Rapid Maxillary Expansion (RME) as a treatment option. Three-dimensional imaging, such as CBCT, enhances clinical practice in orthodontics by enabling personalized treatment based on individual patient characteristics. Objective. This study aimed to assess the morphology and degree of ossification/skeletal maturation of the mediopalatine suture using 3D imaging (CBCT). The secondary aim was to correlate the stages of suture maturation with patient age and skeletal anomalies. Material and method. CBCT images from 56 patients (aged 11 to 65 years) were analyzed. The mediopalatine suture maturation stages were determined according to Angelieri’s classification. Dental anomalies were diagnosed using comprehensive documentation. Statistical analysis was performed to correlate maturation stages with patient age and dental anomalies. Results. There was a weak and statistically non-significant negative correlation between patient age and suture maturation stage. Gender did not significantly influence the ossification of the mediopalatine suture. Conclusions. These findings suggest that the degree of ossification of the mediopalatine suture is independent of both the age of the patients and the presence of orthodontic anomalies.

Assessment of the Trabecular Bone Microstructure Surrounding Impacted Maxillary Canines Using Fractal Analysis on Cone-Beam Computed Tomography Images.

To assess the impact of the presence or position (buccal/palatal) of impacted canines on trabecular bone density using fractal analysis (FA) on cone-beam computed tomography (CBCT) images, and to compare the results with a control group without impacted canines. This retrospective study included 41 patients with unilateral impacted canines (30 palatal, 11 buccal) and a control group of 39 patients who underwent surgically assisted rapid maxillary expansion. All patients had CBCT images recorded for diagnostic and treatment purposes. Cross-sectional CBCT images were obtained between the first and second premolars on both sides of the patients' maxilla. From these images, fractal dimension (FD) was measured in a 20 × 20 pixel region of interest in the trabecular bone using the ImageJ software. The FD values were significantly higher on the impacted side in the impacted canine group (p = 0.02). Within the impacted canine group, a significant increase in FD was observed on the impacted side in the buccal-impacted subgroup (p = 0.02), while no significant difference was observed in the palatal-impacted subgroup (p > 0.05). According to the results of our study, there is an association between the position of the impacted canine and trabecular bone density. An increased trabecular bone density may play a role in the etiology of buccally impacted canines. Clinicians should consider anchorage planning, and appropriate force level, during the forced eruption of buccally impacted canines with high surrounding bone density, to minimize undesirable movements and achieve optimal treatment outcomes.

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.

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. This study was a two-arm, parallel-assignment, RCT with a dual-centre design conducted at two teaching hospitals in Italy. 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. 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. 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. 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). 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. 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. 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. The trial was registered at ClinicalTrials.gov (ID: NCT05135962).

Primary Headache Relief in Paediatric Patients Following Rapid Maxillary Expansion: a Prospective Study and Cephalometric Changes Analysis.

Primary headaches (PH) are a group of disorders greatly impairing quality of life, highly prevalent in growing population. Previous studies suggested a rhinogenic involvement in PH episodes. Modifications of nasal cavities and septum take place during rapid maxillary expansion (RME). This study aims to investigate the role of skeletal modifications due to RME on PH episodes. Sixty-eight growing patients (30/38 MF 7-12 y.o 9.2 ± 1.3 SD) were enrolled. All the selected sample patients reported at least 12 PH episodes in the previous year and were diagnosed with maxillary constriction to be treated with RME. Changes in PH episodes before and after this orthodontic procedure were analysed using paired t-tests. Correlations between age and PH episodes were assessed using Spearman correlation coefficients. Correlations between cephalometric changes and PH episodes were investigated using paired t-tests. RME produces significant modifications in maxillary and nasal width and lower nasal length and decreased monthly episodes of PH significantly. It can be supposed and inferred that RME has beneficial effects on PH in growing patients.