Hyrax Expander Research Articles

Maxillary expansion, constriction, and protraction through facial mask to correct anterior crossbite: case report

Introduction: Maxillary protraction with or without rapid maxillary expansion (RME) is the therapy of choice for early skeletal Class III malocclusion caused by maxillary deficiency. Objective: To report a clinical case of rapid maxillary expansion and constriction with maxillary protraction in boy with skeletal Class III at mixed dentition. Report: A boy aged 9 years and 3 months, with skeletal Class III malocclusion and anterior crossbite of -3mm was treated with a protocol of maxillary expansion and constriction by Hyrax expander associated with maxillary protraction by Petit facial mask. For 4 days, the expander was opened by 2/4 turn in the morning and closed by 2/4 turn in the evening. Elapsed that period, the boy wore the face mask delivering 500N force, for 14 hours per day, for 3 months. After overcorrection, the mask was used during the night delivering a 300N force. Results: The treatment achieved a 2.5mm overjet, with good maxilla-mandible transversal relationship and good facial profile. Conclusion: The protocol of maxillary expansion and constriction followed by maxillary protraction with Petit mask was effective to correct the anterior crossbite and the early skeletal Class III malocclusion caused by anterior-posterior maxillary deficiency.

Use of hyrax distractor in maxillary hypoplasia associated with cleft lip and palate patients

Context: Use of hyrax expander for palatal arch lengthening (anteroposterior) is not new, but large series with long-term follow-up is lacking. Aims: The aim of this study was to evaluate surgically assisted rapid maxillary expansion for hypoplastic maxilla, its efficacy, patient's satisfaction, and relapse rates. Settings and Design: A prospective study was done in PGD of Plastic Surgery, KGMU, Lucknow, between October 2014 and December 2015. Subjects and Methods: Fifteen patients with maxillary hypoplasia associated with cleft lip and palate underwent anterior segmental maxillary osteotomy. Distraction of anterior segment was done with a tooth-anchored hyrax expansion screw oriented in anteroposterior direction. Distraction was started on the 7th day. After desired advancement, the device was left intact for a consolidation period of 3 months and follow-up for any complication was done at the end of 6 months. Statistical Analysis Used: IBM SPSS version 20 software was used. Data expressed as number (percentage) and mean ± standard deviation, Student's t-test and ANOVA were used to compare mean between groups. Results: Bony landmarks sella–nasion–A point angle, maxillary length (ANS-PNS), mean space created on one side (mesial border of first molar to distal border of first premolar), and point A-N perpendicular improved significantly (P

The cost of orthodontic treatment in children during the mixed bite period

In order to analyze the complexity and cost of methods of modern orthodontic treatment for children in the mixed bite period as well as to determine the necessary costs for eliminating dentoalveolar anomalies in primary school children taking into account the prevalence of anomalies we studied the duration and frequency of orthodontist visits during treatment using the 2x4 technique, a removable plate with artificial teeth, a ring with a spacer, a plate with a front bite pad, a plate with a shutter for the tongue, and Twin-block appliance, Dilar mask in combination with an expansion apparatus, plates with a screw, appliance with a hyrax expansion screw. Based on the complexity the salary of the orthodontist and other personnel, the costs of maintaining the doctor’s workplace and the dental technician are calculated. The cost of consumables at the clinical and dental stages was determined considering the purchase prices and the cost of a specific manipulation by weighing or measuring. When calculating the necessary funding for early orthodontic treatment modern data on the prevalence and structure of orthodontic pathology in children during the mixed bite period were used. It was found that the complexity of modern orthodontic treatment during the mixed bite period varies from 5.55 hours (spacer with a ring for premature loss of a temporary tooth) to 10.73 hours in the treatment of a distal bite with a twin-block device. The cost of orthodontic treatment in mixed bite varies from 12.6 thousand rubles (a spacer with a ring for premature loss of a temporary tooth) to 33.4 thousand rubles for the treatment of a mesial bite using a Dilar mask in combination with an expanding device. Given the prevalence of dentoalveolar anomalies in children during mixed bite period, the necessary financial costs for orthodontic treatment per child examined should be at least 30 thousand rubles, and at least 40 thousand rubles for a child with a dentoalveolar anomaly.

Bone-borne accelerated sutural expansion: A microcomputed tomography study in rabbits.

In this study, we evaluated the effect of bone-borne accelerated expansion protocols on sutural separation and sutural bone modeling using a microcomputed tomography system. We also determined the optimum instant sutural expansion possible without disruption of bone modeling. Sixteen New Zealand white rabbits, 20 to 24weeks old, were randomly divided into 4 experimental groups. Modified hyrax expanders were placed across their interfrontal sutures and secured with miniscrew implants located bilaterally in the frontal bone. The hyrax appliances were activated as follows: group 1 (control), 0.5-mm per day expansion for 12days; group 2, 1-mm instant expansion followed by 0.5mm per day for 10days; group 3, 2.5-mm instant expansion followed by 0.5mm per day for 7days, and group 4, 4-mm instant expansion followed by 0.5mm per day for 4days. After 6weeks of retention, sutural separation and sutural bone modeling were assessed by microcomputed tomography and quantified. Statistical analysis was performed using Kruskal Wallis and Mann-Whitney U tests and the Spearman rho correlation (P<0.05). Median amounts of sutural separation ranged from 2.84 to 4.41mm for groups 1 and 4, respectively. Median bone volume fraction ranged from 59.96% to 69.15% for groups 4 and 3, respectively. A significant correlation (r=0.970; P<0.01) was observed between the amounts of instant expansion and sutural separation. Pending histologic verifications, our findings suggest that the protocol involving 2.5mm of instant expansion followed by 0.5mm per day for 7days is optimal for accelerated sutural expansion. When 4mm of instant expansion was used, the sutural bone volume fraction was decreased.

Is there an optimal initial amount of activation for midpalatal suture expansion?

Accelerated bone-borne expansion protocols on sutural separation and sutural bone formation were evaluated via histomorphometry and immunohistochemistry to determine the optimal initial activation without disruption of bone formation. Sixteen New Zealand white rabbits were randomly divided into fourgroups. Modified Hyrax expanders were placed across the midsagittal sutures and secured with miniscrew implants with the following activations: group1 (control), 0.5 mm expansion/day for 12days; group2, 1 mm instant expansion followed by 0.5 mm expansion/day for 10days; group3, 2.5 mm instant expansion followed by 0.5 mm expansion/day for 7days; and group4, 4 mm instant expansion followed by 0.5 mm expansion/day for 4days. After 6weeks, sutural expansion and new bone formation were evaluated histomorphometrically. Statistical analysis was performed using Kruskal-Wallis/Mann-WhitneyU tests and Spearman's rho correlation (p < 0.05). The smallest median sutural separation was observed in group1 (3.05 mm) and the greatest in group4 (4.57 mm). The lowest and highest amount of bone formation were observed in group4 (55.82%) and in group3 (66.93%), respectively. Immunohistochemical analysis revealed significant differences in median levels of alkaline phosphatase and osteopontin expression between all experimental groups. The highest level of these proteins was attained in group3, followed by groups2, 1, and 4, respectively. Sutural appositional bone formation corresponded with the amount of initial expansion to apoint. When initial expansion was increased to 4 mm, sutural bone remodeling was disturbed and new bone formation was decreased. The most effective sutural expansion was achieved with 2.5 mm initial activation followed by 0.5 mm expansion/day for 7days.

Rapid arch expansion in cleft lip and palate children: comparison between fan-shaped expander and hyrax-type expander by using cone beam computed tomography

Purpose: The aim of the current study was to evaluate the skeletal and dentoalveolar effects of rapid palatal expansion (RPE) in children with cleft lip and palate (CLP) treated with 2 expanders. Methods: Twenty Egyptian children with complete unilateral or bilateral CLP exhibiting maxillary transverse deficiency were divided randomly into 2 groups according to the appliance used for expansion: (A) fan expander group and (B) hyrax expander group. Cone-beam computed tomography (CBCT) images were taken before and immediately after expansion procedure. Results: There was non-significant vertical movement of the maxilla for the 2 groups. On the transverse plane, there was more anterior expansion and posterior restriction for the fan group. However, the hyrax group showed significant posterior as well as anterior expansion. Both groups showed significant tipping between both sides posteriorly and anteriorly. Mandibular expansion was non-significant. Conclusion: Fan expander showed better results for children with cleft palate requiring anterior expansion only. Hyrax expander is better used for cases seeking for posterior and anterior expansion.

Effect of three types of rapid maxillary expansion: a three-dimensional finite element study

Objective: To evaluate the transverse displacement, stress distribution and tendency of change in tooth, alveolar bone and mid-palatal suture using three kinds of rapid maxillary expansion methods. Methods: Cone-beam CT image data was obtained by scanning skulls of a volunteer. Three-dimensional models of maxillary complex were re-established using Mimics and Geomagic Studio and models of Hyrax expander, Haas expander and miniscrew-assisted rapid palatal expander (MARPE) were established using ANSYS Workbench. Stress distribution, displacement and tendency of change in tooth, alveolar bone and mid-palatal suture were evaluated. Results: Hyrax expander brought 0.105 mm lateral displacement of crown, 0.022 mm mid-palatal suture width increase, wedge opening and clockwise rotation tendency of maxilla. Haas expander created uniform stress distribution, 0.216 mm lateral displacement of crown, and 0.031 mm mid-palatal suture width increase. In MARPE model, the lateral displacement of crown was 0.267 mm, and mid-palatal suture width increased 0.315 mm. The maximum of mid-palatal suture expansion and stress distribution appeared in the middle region, and maxilla had tendency of counterclockwise rotation. Conclusions: The lateral changes of teeth and bones brought by MARPE were the most significant. Haas expander had some advantages in comparison with Hyrax.

Effect of Piezoelectric Sutural Ostectomies on Accelerated Bone-Borne Sutural Expansion

The present study investigated the effect of piezoelectric sutural ostectomies on accelerated bone-borne sutural expansion. Sixteen male New Zealand white rabbits (20 to 24weeks old) were randomly divided into 4 experimental groups (n=4): group 1, conventional rapid sutural expansion; group 2, accelerated sutural expansion; group 3, accelerated sutural expansion with continuous ostectomy; and group 4, accelerated sutural expansion with discontinuous ostectomy. All sutural ostectomies were performed using a piezoelectric instrument (Woodpecker DTE, DS-II, Guangxi, China) before expander application with the rabbits under anesthesia. Modified hyrax expanders were placed across the midsagittal sutures of the rabbits and secured with miniscrew implants located bilaterally in the frontal bone. The hyrax expanders were activated 0.5mm/day for 12days (group 1) or with a 2.5-mm initial expansion, followed by 0.5mm/day for 7days (groups 2 to 4). After 6weeks of retention, the bone volume fraction, sutural separation, and new bone formation were evaluated using micro-computed tomography and histomorphometry. Statistical analysis was performed using Kruskal-Wallis and Mann-Whitney U tests and Spearman's rho correlation (P<.05). Ranking of the median sutural separation was as follows: group 1, 3.05mm; group 2, 3.97mm; group 4, 4.78mm; and group 3, 5.66mm. The least and most bone formation were observed in groups 1 (63.63%) and 3 (75.93%), respectively. Spearman's correlation showed a strong, positive, and significant correlation (r=0.932; P<.01) between the new sutural bone formation and amount of sutural separation. Piezoelectric sutural ostectomies increased the rate of sutural separation and promoted new sutural bone formation/osteogenesis. Continuous ostectomy gave better results than discontinuous ostectomy.

Effects on Alkaline Phosphatase Level in Crevicular Fluid Produced by Rapid Palatal Expansion with Hyrax Expander

Effects on Alkaline Phosphatase Level in Crevicular Fluid Produced by Rapid Palatal Expansion with Hyrax Expander

Impact of rapid maxillary expansion on nasomaxillary complex volume in mouth-breathers.

ABSTRACTObjective: To assess the volumetric changes that occur in the nasomaxillary complex of mouth-breathing patients with transverse maxillary deficiency subjected to rapid maxillary expansion (RME). Methods: This was a controlled, prospective intervention study involving 38 mouth-breathing patients presenting with transverse maxillary deficiency, regardless of malocclusion type or race. Twenty-three of them comprised the experimental group, which was composed of 11 (47.8%) boys, and 12 (52.2%) girls, with a mean age of 9.6 years, ranging from 6.4 to 14.2 years and standard deviation of 2.3 years; and 15 of them comprised the control group, composed of 9 (60%) boys and 6 (40%) girls with an mean age of 10.5 years, ranging from 8.0 to 13.6 years, and standard deviation of 1.9 years. All patients were scanned (CT) according to a standard protocol: Initial CT (T1), and CT three months thereafter (T2), and the patients in the experimental group were treated with RME using a Hyrax expander for the correction of maxillary deficiency during the T1-T2 interval. The CT scans were manipulated using Dolphin® Imaging version 11.7 software for total and partial volumetric assessment of the nasomaxillary complex. Results: The results revealed that in the experimental group there was a significant increase in the size of the structures of interest compared to the control group, both in general aspect and in specific regions. Conclusions: Rapid maxillary expansion (RME) provided a significant expansion in all the structures of the nasomaxillary complex (nasal cavity, oropharynx, right and left maxillary sinuses).

One-Step Surgical Correction of Transverse and Anteroposterior Maxillary Deficiencies Using Wire Fixation. A New Approach and Long-Term Stability

To describe a retrospective assessment of the long-term stability of a new approach using wire fixation for 1-step surgical correction of transverse and anteroposterior maxillary deficiencies. The authors implemented a case series of 5 adult patients (3 men and 2 women; mean age, 31.4yr) needing maxillary advancement less than 5mm and had transverse maxillary deficiency greater than 7mm who underwent total Le Fort I and median palatal suture osteotomies and had their maxilla advanced and stabilized bilaterally with stainless steel wire. Transverse expansion was performed using a Hyrax expander, which also was used for retention for 4months after completion of the planned expansion. Follow-up included clinical examination and studies of lateral radiographs and plaster models preoperatively (T0), soon after completion of maxillary expansion (T1), 4months after T1 (T2), 12months after T1 (T3), and an average of 4.8years (minimum, 4yr 1month; maximum, 5yr; standard deviation, 0.3yr) after T1 (T4). Maxillary expansions measured at the most cervical points on the palatal face of the upper first premolars and of the upper first molars at T2 were 7.8 and 7.4mm on average, respectively. In all cases, surgery promoted maxillary anteroposterior advancement. Anteroposterior maxillary skeletal measurements of the angle formed by the sella, nasion, and A point; the distance from the vertical reference line to the A point (A-VRL); the distance of the VRL to the cementoenamel junction (CEJ); and the distance from the perpendicular line of the nasion (Nperp) to the CEJ showed a substantially increase at T1 (P<.05) and stability at T2, T3, and T4; however, A-VRL presented a significant relapse at T4 compared with T1 (P=.037) and T2 (P=.027). The soft tissues expanded at the same rate as the skeletal tissues. The anteroposterior soft tissue measurements Nperp to superior lip and Nperp to the A' point showed a substantial increase at T2 (P<.05) and stability at T3 and T4. The measurements associated with anteroposterior correction were stable at T4. The proposed technique provides long-term stability of maxillary expansion and anteroposterior repositioning with only 1 surgical intervention. However, considering the small number of patients, a multicenter study is needed before a definitive conclusion can be reached.

Assessment of the efficiency of Erbium-YAG laser as an assistant method to rapid maxillary expansion: An in vivo study.

Maxillary transverse deficiency (MTD) is one of the most pervasive and common skeletal problems in the craniofacial complex. This study aimed to evaluate the effect of associating the application of Erbium-YAG laser with rapid maxillary expansion (RME) for treating MTD in young adult patients with permanent dentition in regard to skeletal and dental effects. Twenty-four subjects, aged from 15.5 to 19 years and needing RME as a therapeutic procedure, were randomly assigned to either the laser group (n=12) or the control group (n=12). The RME was realized by a two bands hyrax expander cemented on upper first molars. Patients in the laser group were undergone mucosal-bony perforations along the midpalatal suture every month, for three consecutive months, using Erbium-YAG laser. Postero-anterior cephalograms were taken for all patients. Skeletal and dental changes before and after RPE as well as at the end of the retention phase were collected and compared for both groups. Total time needed for expansion and retention were recorded and compared. The findings showed more significant changes in most maxillofacial components in the laser group after the expansion phase. However, there was no significant differences with respect to retention or total treatment duration. Laser assisted rapid maxillary expansion (LARME) can be a good approach to use for improving skeletal effects in young adult patients suffering from MTD.

Mini-Implant Screws for Bone-Borne Anchorage: A Biomechanical In Vitro Study Comparing Three Diameters.

To evaluate the maximum strength and the maximum aperture supported by mini-implant screws of three different diameters in an in vitro rapid maxillary expander model. Fifteen appliances were mounted in artificial bone polyurethane blocks. In each appliance, a Hyrax expander anchored by four mini-implant screw sets of three different diameters were divided into: group 1 (n = 5), 1.8-mm-diameter screws; group 2 (n = 5), 2.0-mm-diameter screws; and group 3 (n = 5), 2.2-mm-diameter screws. All sets (bone blocks + expander + four mini-implants) were inserted into a customized and standardized device that simulated a mid-palate disjunction. The expanders were activated to mechanically test the insertion of the mini-implant into the devices until breakage or deflection of screws occurred. The number of activations, the maximum supported strength, and the maximum expander aperture values until failure were recorded for each group. Data were subjected to a Student t test at a significance level of 5%. There were no significant differences between the groups regarding the number of activations up to the maximum supported strength. The expander achieved aperture values where differences were slightly significant just between groups 1 and 2 (P = .048). There was a significant difference between groups 1 and 3 regarding the maximum supported load (P = .039). Regardless of the mini-implant screw diameters, the expander device used in this anchorage system model withstood strengths and aperture rates beyond those that may be required during clinical rapid maxillary expansion.

A comparison of the sagittal and vertical dentofacial effects of maxillary expansion produced by a memory screw and a hyrax screw

Abstract Aim The aim of the present study was to investigate and compare the cephalometric effects of a conventional Hyrax expansion screw and a memory screw on the skeletal and dentoalveolar structures and soft tissues of the face. Methods Thirty-two patients with a maxillary transverse deficiency were divided into two groups. A memory-screw group included 17 patients (nine females and eight males), while a Hyrax-screw group was comprised of 15 patients (eight females and seven males). The mean ages of the subjects in the memory-screw and Hyrax-screw groups were 13.00 ± 1.29 and 12.58 ± 1.50 years, respectively. Lateral cephalograms were taken of the patients at the beginning of the treatment (T1), at the end of expansion (T2) and retention periods (T3). The mean expansion period was 7.76 ± 1.04 days in the memory-screw group and 35.46 ± 9.39 days in the Hyrax-screw group. The Shapiro-Wilk Normality test was used to determine whether the investigated parameters were homogeneous. To determine the treatment changes within the groups, a paired t-test and Wilcoxon Signed Rank test were applied to the homogeneous and non-homogeneous parameters, respectively. A comparison between the groups was carried out using the Student’s t-test for homogeneous parameters and the Mann-Whitney U test for all others. Results A results summary indicates that mid-palatal sutural opening and subsequent important skeletal and dental expansions were obtained in all patients. The maxilla moved anteriorly and inferiorly in both groups while the mandible rotated inferiorly and posteriorly but to a greater extent in the memory-screw group. Conclusion The newly-developed memory expansion screw takes advantage of rapid and slow maxillary expansion protocols. The suture is opened and the maxilla expanded with relatively lighter forces over a shorter time. The RME using the memory screw resulted in similar sagittal and vertical changes to those produced by the Hyrax screw.

Analysis of the dentoalveolar effects of slow and rapid maxillary expansion in complete bilateral cleft lip and palate patients: a randomized clinical trial.

The purpose of this study was to compare the dentoalveolar effects of slow (SME) and rapid (RME) maxillary expansions in patients with complete bilateral cleft lip and palate (BCLP). A sample of 50 patients with BCLP and maxillary arch constriction was randomly and equally allocated into two groups. Group SME comprised patients (mean age of 8.8years) treated with quad-helix appliance. Group RME comprised individuals (mean age of 8.9years) treated with Hyrax expander. Digital dental models obtained immediately pre-expansion (T1) and 6months after the active expansion period (T2) were used for measuring maxillary dental arch widths, arch perimeter, arch length, palatal depth, buccolingual inclination of posterior teeth and differential amount of expansion accomplished at the canine and molar regions. Inter-phase and intergroup comparisons were performed using paired t tests and t tests, respectively (p<0.05). SME and RME caused significant increase of arch widths and arch perimeter. Arch length and palatal depth decreased nonsignificantly with SME but significantly with RME. Buccal tooth inclination was significant only for maxillary deciduous canines in both groups. The quad-helix appliance showed a significant differential expansion between anterior and posterior regions. No differences were observed between SME and RME for all variables. Differences were not found between the dentoalveolar effects of SME and RME in patients with BCLP. SME demanded a greater therapy time compared to RME. Both expansion procedures can be similarly indicated to correct maxillary arch constriction in patients with BCLP in the mixed dentition.

Effects of rapid maxillary expansion on nasal cavity dimensions and airway resistance

Background: Rapid maxillary expansion is a common treatment for posterior cross-bites that has also shown to improve nasal breathing.Methods: Thirteen oral breather patients with posterior cross-bite were studied. Treatment consisted in rapid maxillary expansion with a fully bonded appliance including a bite-block and a hyrax expansion screw. Before and after treatment, CT scans and active anterior rhinomanometry were performed to each patient. Data was analyzed with the non-parametric Wilcoxon statistical test and correlation between palatal expansion and increase of airflow in each patient was assessed.Results: The CT scan showed that transversal dimensions were significantly increased (P&lt;0.001) in most areas after treatment, considering the right and left side separately. Rhinomanometry also showed statistical differences (P&lt;0.001) in all parameters studied when compared before and after treatment. Positive correlation was observed between palatal expansion and increase of airflow.Conclusions: All patients improved oral breathing habit clinically and there is also statistical evidence that the nasal cavity increased its transversal dimensions, measured by CT scan and that patients increased their airflow through the nasal cavity, measured by rhinomanometry.

Evaluation and comparison of root resorption between tooth-borne and tooth-tissue borne rapid maxillary expansion appliances: A CBCT study.

To compare volumetric root resorption after rapid maxillary expansion (RME) between tooth-borne and tissue-borne appliances using CBCT. Repair in resorption cavities after 6 months of fixed retention was also compared. A sample of 33 subjects were randomly divided into two groups: Hyrax (n = 16) and Haas (n = 17). CBCT scans were taken 6 months before expansion, immediately after expansion, and 6 months after fixed retention. Mimics Innovation V 16.0 software was used for segmentation and volumetric measurement of 198 teeth. Bland-Altman plots, independent samples t test, repeated measures analysis of variance, and the Friedman test were used for statistical analysis. Differences in root resorption after RME and repair after retention were not significant between the hyrax and Haas appliances or between male and female. Significant differences were found between preexpansion and postexpansion root volumes in the first premolars and molars--even in unattached second premolars. When the percentage of root volume loss is considered, no significant difference was found between the first premolar, second premolar, and first molar. Volumetric changes after 6 months of retention were not statistically significant. More resorption was observed in the Hyrax expander group. But it was not statistically significant. Repair was observed after 6 months of retention. Heavy RME forces affected premolars and molar similarly.

Management of the transverse dimension (expansion) with microscrews (TADS)

An effective alternative for the correction of the skeletal transverse maxillary deficiency is through expansion with the use of Microscrews or temporary skeletal anchorage devices (TADS). With this technique we can perform separation or disjunction of the midpalatal suture so the maxillary processes may separate to correct the transverse maxillary discrepancy in relation to the lower arch without dentoalveolar compensation. This means that pure bone expansion will be performed avoiding dental and/or alveolar compensations that may be deceiving regarding the amount of expansion required for the correction or alignment of the arches. Two or four microscrews are placed directly bilaterally on the palate so that afterwards an acrylic plate with expansion screw is cemented over the microscrews and this in turn rests or leans on the palatal mucosa avoiding direct contact with the tooth crowns to prevent dentoalveolar inclinations and thus perform a purely bony expansion. Hyrax and Hass-type expansion screws were used and rapid palatal expansion was performed with two activations per day. This type of expansion may be orthopedic or surgically assisted. The technique is simple, inexpensive, accurate and with a high rate of effectiveness, but defi nitely requires knowledge of anatomy, physiology and of course mechanical basis for treatment success. Key words: Skeletal transverse defi ciency, microscrews, Hyrax-type screw and Hass-type screw, disjunction of the suture.

Evaluation of transverse maxillary expansion after a segmental posterior subapical maxillary osteotomy in cleft lip and palate patients with severe collapse of the lateral maxillary segments.

Objective : The purpose of this longitudinal retrospective study was to evaluate transverse maxillary expansion after a Schuchardt or segmental posterior subapical maxillary osteotomy (SPSMO) in patients with cleft lip and palate (CLP). A second aim was to compare these data with data for adult patients without CLP who were receiving a surgical assisted rapid palatal expansion (SARPE). Method : The study group comprised 19 patients with CLP and a severe transversally collapsed maxilla who were treated with SPSMO followed by hyrax expansion at the University Hospitals Leuven. Dental casts of the 19 patients were analyzed before treatment, at maximum expansion, during orthodontic treatment, at the completion of orthodontic treatment. and 2 years after orthodontic treatment and were measured at the canine, premolar, and molar levels. Adult patients without CLP who were enrolled in a prospective study served as the control group. Results : Maxillary expansion within the study group was significantly greater (P < .05) at all measured levels compared with the maxillary arch before treatment. No significant relapse was measured in the study group 2 years after orthodontic treatment. When comparing the study and control groups, the only statistical difference was that canine expansion was significantly greater in the study group. Conclusion : SPSMO followed by maxillary expansion and orthodontic treatment is an appropriate treatment option to correct a severe transversally collapsed maxilla in patients with CLP. The overall treatment effect of SPSMO expansion is comparable with the effects of SARPE, although canine expansion was greater in the SPSMO group.

Dentoskeletal effects of 3 maxillary expanders in patients with clefts: A cone-beam computed tomography study

The purpose of this study was to evaluate the skeletal and dental changes in the maxillae of patients with clefts treated with 3 expanders: hyrax, fan-type, and inverted mini-hyrax supported on the first premolars. Thirty patients with unilateral cleft lip and palate with transverse maxillary deficiency were divided into 3 groups, according to the type of expander that they used. Cone-beam computed tomography images were taken before and 3 months after expansion, and the paired t test was used to evaluate the changes in each group. The subjects in the inverted mini-hyrax group showed significant forward displacement of the maxilla (P <0.05). On the transversal plane, the hyrax group showed greater expansion in the posterior region than in the anterior region (P <0.05). However, the fan-type and the inverted mini-hyrax groups showed significantly greater maxillary expansion anteriorly than posteriorly (P <0.05). There was a greater tendency for buccal inclination of the supporting teeth when the fan-type was used. The cleft and the noncleft sides expanded symmetrically with all appliances, and there was no difference in dental tipping between these sides (P >0.05). The hyrax expander showed better results for cleft patients requiring anterior and posterior maxillary expansion. The inverted mini-hyrax most effectively restricted posterior expansion, optimizing anterior expansion without causing as much buccal tipping of the supporting teeth as did the fan-type.