Effects of rapid maxillary expansion on Holdaway soft tissue measurements

The objective of the present study was to evaluate short-term soft tissue changes caused by rapid maxillary expansion (RME) in 18 subjects (15 females and 3 males) (mean age 13 years 6 months) with a bilateral posterior crossbite. Lateral cephalograms of the patients were obtained at three different time points: before RME (T1), after maxillary expansion (mean = 0.82 month) (T2), and after retention (mean = 5.95 months) (T3). Holdaway soft tissue measurements were used for the evaluation of soft tissue changes. Data were analysed statistically by means of paired t-tests. The facial soft tissue angle decreased (P < 0.05), and H angle and skeletal profile convexity increased significantly (P < 0.001) at T2. During T3, the increase in the facial soft tissue angle and the decrease in H angle were minimal and not significant, while skeletal profile convexity significantly decreased (P < 0.001). The results of this study indicate that RME may affect Holdaway soft tissue measurements.     

Effects of different rapid maxillary expansion appliances on facial soft tissues using three-dimensional imaging

Objective:To determine three-dimensional (3D) effects of three different rapid maxillary expansion (RME) appliances on facial soft tissues.Materials and Methods:Forty-two children (18 boys, 24 girls) who required RME treatment were included in this study. Patients were randomly divided into three equal groups: banded RME, acrylic splint RME, and modified acrylic splint RME. For each patient, 3D images were obtained before treatment (T1) and at the end of the 3-month retention (T2) with the 3dMD system.Results:When three RME appliances were compared in terms of the effects on the facial soft tissues, there were no significant differences among them. The mouth and nasal width showed a significant increase in all groups. Although the effect of the acrylic splint RME appliances on total face height was less than that of the banded RME, there was no significant difference between the appliances. The effect of the modified acrylic splint appliance on the upper lip was significant according to the volumetric measurements (P < .01).Conclusions:There were no significant differences among three RME appliances on the facial soft tissues. The modified acrylic splint RME produced a more protrusive effect on the upper lip.     

A photogrammetric technique for the analysis of palatal three-dimensional changes during rapid maxillary expansion

The aim of this study was to assess, by a digital photogrammetric technique, the relative dimensional changes before and after rapid maxillary expansion (RME). The transverse diameters and volumetric variations of the palate were measured by photogrammetry on study casts taken at three different phases of therapy: at the beginning of treatment (T1), on removal of the rapid expander, after expansion and retention for three months (T2), and six months after appliance removal (T3). The sample consisted of 30 children, (age range 7-8 years), all with a crossbite; 15 were angle Class I, six Class II and nine Class III. They were treated with an acrylic splint expander with two turns per day until the maxillary molar palatal cusps were in contact with the mandibular molar buccal cusps. The RME device was used as a passive retainer for three months, after which it was removed. During the following six months, no retention was used and no orthodontic treatment was undertaken. The findings demonstrated a significant relapse (P < 0.001) in the dental transverse diameter in all patients six months after appliance removal, although the palatal volume remained stable.     

改良固定斜面导板矫治第二磨牙正锁

目的 观察应用改良固定斜面导板矫治第二磨牙正锁 后牙结构的变化。方法 应用改良固定斜面导板矫治24例上颌第二磨牙正锁伴安氏Ⅱ类错畸形。男9例,女15例,年龄12～15岁,平均13.5岁,并进行术前、术后X线头影测量分析。结果 经过3～4个月的矫治,上颌第二磨牙正锁解除,下颌前移,尖牙及磨牙关系由Ⅱ类变为Ⅰ类,软组织侧貌改善明显更趋协调,下颌磨牙牙冠高度明显增加,上颌磨牙萌长不明显。结论 改良固定斜面导板矫治上颌第二磨牙正锁合并安氏Ⅱ类错畸形,快速有效,不引起上颌磨牙的伸长,获得满意的软硬组织变化,尤其适用于低角患者。     

Cephalometric evaluation of rapid and slow maxillary expansion in patients with BCLP: Secondary data analysis from a randomized clinical trial

Objective:To compare the dentoskeletal effects of rapid (RME) and slow (SME) maxillary expansion in patients with bilateral complete cleft lip and palate (BCLP).Materials and Methods:This was a secondary analysis of a previous randomized controlled trial (RCT). Forty-six patients (34 male, 12 female) with BCLP and posterior crossbite (mean age of 9.2 years) were randomly assigned to two study groups. Group RME comprised subjects treated with Haas/Hyrax expander. Group SME included patients treated with quad-helix appliance. Cone-beam computed tomography (CBCT) was performed before expansion (T1) and after appliance removal at the end of a 6-month retention period (T2) for a previous RCT that compared the transverse skeletal effects of RME and SME. CBCT-derived cephalometric images were generated and cephalometric analysis was performed using Dolphin Imaging Software (Chatsworth, Calif). Intergroup comparisons were performed using t tests (P < .05).Results:Baseline forms were similar between groups. No significant differences between RME and SME groups were found.Conclusions:Rapid and slow maxillary expansion produced similar sagittal and vertical changes in patients with BCLP. Both Haas/Hyrax and quad-helix appliances can be used in patients with vertical facial pattern. Clinical relevance: RME and SME can be equally indicated in the treatment of maxillary arch constriction in patients with BCLP.     

上颌前牵引联合快速扩弓矫治儿童骨性Ⅲ类错前后软硬组织变化

目的:探讨上颌前牵引联合快速扩弓对儿童骨性Ⅲ类错的矫治效果。方法:对28例儿童骨性Ⅲ类错病人(7～10岁)进行上颌前牵引治疗,在前牵引前快速扩弓1周。分别在治疗开始(T0)和结束(T1)时拍摄头颅定位侧位片,进行定点测量分析。结果:①硬组织变化:ANB角增加5.37°(P<0.05),Wit’s值增加5.74 mm(P<0.05),Ptm-A增加2.49 mm(P<0.05),Yaxis增加1.82°(P<0.05);SNB角减小0.75°(P>0.05),Go-Me、Co-Gn分别增加0.64 mm、2.21 mm,但P>0.05,SN-PP减小0.61°(P>0.05),PP-MP增加5.54°(P<0.05),下面高、下面高/全面高分别增加3.98(P<0.05)、1.61(P>0.05);U1-NA角增加3.10°(P<0.05),L1-NB角减小1.23°(P<0.05),Ms6-PP距增加1.13 mm(P<0.05);②软组织测量项目变化:面型角增大5.98°,颏唇角减小2.45°、H角增大5.2°,上唇-E线距增大1.42 mm,下唇-E线距减小1.18 mm(P<0.05)。结论:前牵引联合快速扩弓矫治儿童骨性Ⅲ类错,可产生显著治疗效果,能促进上颌骨的生长,使面型改善,但下颌出现顺时针旋转,高角病人慎用。     

Skeletal alterations associated with the use of bonded rapid maxillary expansion appliance

Bonded maxillary expansion appliances have been suggested to control increases in the vertical dimension of the face after rapid maxillary expansion (RME). However, there is still no consensus in the literature about its real skeletal effects. The purpose of this prospective study was to evaluate, longitudinally, the vertical and sagittal cephalometric alterations after RME performed with bonded maxillary expansion appliance. The sample consisted of 26 children, with a mean age of 8.7 years (range: 6.9-10.9 years), with posterior skeletal crossbite and indication for RME. After maxillary expansion, the bonded appliance was used as a fixed retention for 3.4 months, being replaced by a removable retention subsequently. The cephalometric study was performed onto lateral radiographs, taken before treatment was started, and again 6.3 months after removing the bonded appliance. Intra-group comparison was made using paired t test. The results showed that there were no significant sagittal skeletal changes at the end of treatment. There was a small vertical skeletal increase in five of the eleven evaluated cephalometric measures. The maxilla displaced downward, but it did not modify the facial growth patterns or the direction of the mandible growth. Under the specific conditions of this research, it may be concluded that RME with acrylic bonded maxillary expansion appliance did promote signifciant vertical or sagittal cephalometric alterations. The vertical changes found with the use of the bonded appliance were small and probably transitory, similar to those occurred with the use of banded expansion appliances.     

A comparison of the effects of rapid maxillary expansion and fan-type rapid maxillary expansion on dentofacial structures

The aim of this study was to evaluate and compare the sagittal, transverse, and vertical effects of rapid maxillary expansion (RME) and fan-type RME on dentofacial structures. The study group consisted of 34 patients, 14 boys and 20 girls (average age 12.5 years), selected without considering their skeletal class and sex. The fan-type RME group comprised 17 subjects, who had an anterior constricted maxilla with a normal intermolar width. The RME group comprised 17 other subjects, who had a maxillary transverse discrepancy with a posterior crossbite. The records obtained for each patient included a lateral and a frontal cephalometric film, upper plaster models, and occlusal radiograph obtained before treatment (T1), after expansion (T2), and immediately after a three-month retention period (T3). The data obtained from the evaluation of the records before and after treatment, after treatment and after retention, and before treatment and after retention were compared using paired t-test. Further comparisons between the groups were made using Student's t-test. There was significantly greater expansion in the intercanine than in the intermolar width in the fan-type RME group as compared with the RME group. Downward and forward movement of the maxilla was observed in both groups. The upper incisors were tipped palatally in the RME group, but they were tipped labially in the fan-type RME group. There was significantly greater expansion in the nasal cavity and maxillary width in the RME group as opposed to the fan-type RME group.     

Effects of a modified acrylic bonded rapid maxillary expansion appliance and vertical chin cap on dentofacial structures

The aim of this study was to determine the sagittal, transverse, and vertical effects of a modified acrylic bonded rapid maxillary expansion (RME) device used with a vertical chin cap on dentofacial structures. The study group consisted of 34 patients (25 girls and 9 boys) who were selected without regard to their skeletal class and gender. All subjects had permanent dentition (mean age, 12.7 years) and needed maxillary expansion. Study Group I (RME only) was composed of 17 subjects, and study Group II (RME with vertical chin cap) was composed of 17 subjects. Twenty-nine measurements were made on the patients' cephalometric films and plaster models. The means and standard deviations for linear and angular cephalometric measurements were analyzed statistically, and intra-group and inter group changes were evaluated by paired and Student's t-tests using SPSS 10.1 for windows. We found that the maxilla moved anteriorly relative to the anterior cranial base. The nasal width, maxillary width, intercanine width, mandibular intermolar width, maxillary intermolar width, and overjet all increased, while the upper molars tipped buccally in both groups. In Group I, the mandible rotated posteriorly, the lower anterior facial height increased, and the overbite decreased. These effects were reduced in Group II. We conclude that the vertical chin cap is an effective appliance for preventing the adverse vertical effects of RME in patients with a crossbite and a vertical growth pattern.     

Longitudinal effects of rapid maxillary expansion

OBJECTIVE: To evaluate the long-term effects of rapid maxillary expansion (RME) via banded expanders in the sagittal and vertical facial planes. MATERIALS AND METHODS: The sample consisted of 25 patients who had undergone RME (with either Haas-type or Hyrax hygienic expanders) followed by standard edgewise orthodontic therapy. This sample was compared with a group of 25 patients who had edgewise treatment only and with a control nontreatment group of 26 subjects, matched by age and gender with the patients of the other two groups. Lateral cephalograms were taken before treatment (T1), at the end of treatment (T2), and at 3 years posttreatment (T3), comprising a 5-year average time of observation. RESULTS: RME treatment, in the long-term, did not influence the sagittal position of the apical jaw bases or the facial vertical dimension. CONCLUSION: Unfavorable cephalometric changes resulting immediately after RME are temporary, and therefore concerns about using RME in patients with vertical growth patterns or an extremely convex facial profile are not substantiated.     

Long-term effects of rapid maxillary expansion: a posteroanterior cephalometric evaluation.

The aim of this study was to investigate long-term effects induced by rapid maxillary expansion (RME), followed by comprehensive orthodontic treatment, in a sample of 42 patients compared with normal growth changes in a sample of 20 subjects. Treated subjects underwent Haas-type RME with 2 turns a day (0.25 mm per turn) until the expansion screw reached 10.5 mm (about 21 days). The Haas expander was kept on the teeth as a passive retainer for an average of about 2 months. Immediately after the Haas expander was removed, fixed standard edgewise appliances were placed. Posteroanterior cephalograms were analyzed for each subject in both groups at T1 (pretreatment) and at T2 (long-term observation). The mean age at T1 was 11 years 10 months for both the treated and the control groups. The mean ages at T2 also were comparable (20 years 6 months for the treated group, and 17 years 8 months for the control group). The study included transverse measurements on dentoalveolar structures, maxillary and mandibular bony bases, and other craniofacial regions (nasal, zygomatic, orbital, and cranial). RME followed by edgewise appliance therapy appears to be an effective procedure to increase transverse facial dimensions in the long term, at both the skeletal and the dentoalveolar levels. Significant pretreatment deficiencies in maxillary width, maxillary incisor apex width, and maxillary first molar width remained corrected at a mean age of about 20 years. The initial deficiency in lateroorbital width was also eliminated.     

Does rapid maxillary expansion affect the eruption of upper third molars?

OBJECTIVE: To test the hypothesis that there is no difference in the movement of the upper third molars between rapid maxillary expansion (RME) and non-RME patients. MATERIALS AND METHODS: This study was performed on 30 patients divided into two groups. The study group included 20 patients who had maxillary narrowness and bilateral maxillary third molars and who had undergone RME application. The control group of 10 patients had a bilateral crossbite, had bilateral maxillary third molars, and did not receive orthodontic treatment. The records included lateral and frontal cephalometric films and maxillary plaster models. In the study group, records were taken before expansion (T1), after expansion (T2), and at the retention period (T3). T2 records were not taken in the control group because this period was too short to observe any changes. Friedman tests were used to observe within groups, and the Mann-Whitney U-test was used to see the differences between groups on films and casts. RESULTS: Frontal films showed that vertical eruption occurred after the retention period in the RME cases. Cephalometric films revealed that the angular eruption occurred immediately after expansion. However, the results were not significant with respect to the control group. CONCLUSION: The hypothesis was rejected. Rapid maxillary expansion affects maxillary third molar movement during and after the RME procedure. RME may indicate upper third molar eruption, but the final position of third molar was not different compared to the normal growth pattern.     

Dentofacial effects of two facemask therapies for maxillary protraction: Miniscrew implants versus rapid maxillary expanders

Objective:To compare the dentofacial effects of maxillary protraction with two facemask therapies in growing Class III patients: facemask in association with miniscrew implants (MSI/FM) and facemask with rapid maxillary expanders (RME/FM).Materials and Methods:Forty-three Chinese patients with Class III malocclusion and maxillary deficiency were randomly assigned to a MSI/FM sample of 20 patients and a RME/FM sample of 23 subjects. The changes in dentofacial cephalometric variables from the beginning (T1) to the end of treatment (T2) were compared with t-test for paired samples in both groups and for independent samples between the two groups.Results:No significant cephalometric differences were observed between the two groups in active treatment effects except for maxillary dental variables. However, significant favorable changes in both maxillary and mandibular skeletal components were noted in two groups after treatment. Sagittal measurements showed the maxilla was advanced, mandibular projection was reduced, and the relative sagittal intermaxillary discrepancy improved. Patients experienced additional unfavorable outcomes of clockwise rotation of the mandible as well as retroclination of the lower incisors. The soft tissue profile was improved remarkably in both groups. Proclination of the maxillary incisors and mesialization of the maxillary dentition were significantly different between the two groups. The increases in U1-SN, U1-VR, and U6-VR were 6.41°, 2.78 mm, and 1.24 mm less in the MSI/FM group than in the RME/FM group, respectively.Conclusions:Compared with the RME/FM therapy, the MSI/FM protocol using a smaller magnitude of protraction force improves skeletal relationships and soft tissue profile and reduces the undesired dentoalveolar effects.     

前方牵引治疗单侧完全性唇腭裂患者术后前牙反[牙合]畸形的研究

目的探讨前方牵引治疗单侧完全性唇腭裂（UCLP）患者术后前牙反[牙合]畸形的效果。方法进行前瞻性临床研究设计,UCLP术后骨性前牙反[牙合]患者治疗组18例,年龄9．63±1．24岁,观察对照组14例,平均8．71±1．92岁,均处于生长发育高峰前期。使用前方牵引进行治疗,治疗或观察前后拍摄头颅侧位片并测量,进行成组设计和配对设计t检验。结果UCLP治疗组前方牵引后,上颌骨前移;下颌后移合并后下旋转;上下颌间关系和面型改善明显,上颌与下颌改变的比值为1：1．7。对照组上下颌不调、前牙反覆盖、凹面型加重。结论UCLP术后轻中度骨性前牙反[牙合]畸形,前方牵引能够促进上颌骨向前,改善上下颌骨关系和软组织面型,应该早期矫形治疗。     

Correcting vertically altered faces: orthodontics and orthognathic surgery

Traditional methods of model and cephalometric examination are often unreliable for diagnosis and treatment planning. This article presents soft tissue cephalometric analysis that measures the face, analyzes important dentoskeletal structures that determine facial appearance, and reveals the etiology of malocclusions. A technique for cephalometric treatment planning for guiding esthetic facial changes and the method of occlusal correction are also described. Vertical maxillary excess and vertical maxillary deficiency malocclusions are used to illustrate these techniques.     

Rapid maxillary expansion in growing patients. Hyrax versus transverse sagittal maxillary expander: a cephalometric investigation

The aim of this retrospective study was to cephalometrically evaluate and compare the skeletal and dental effects of a transverse sagittal maxillary expander (TSME) and a Hyrax-type expander (RME) in children with maxillary hypoplasia. Fifty subjects (26 males and 24 females), aged from 6 to 15 years, with a maxillary crossbite caused by basal apical narrowness, were divided into two equal groups. Twenty-five were treated with a TSME and the other 25 with a RME. For each patient, a lateral cephalogram was obtained before treatment (T0) and at the end of the retention period (T1). Changes in the two groups during the observation period were calculated, compared, and statistically analysed with a paired samples t?-test. In the TSME group, SNP-A, I?SN, and I?FH and in the RME group SN-SNP.SNA, N-Me, and U6.PP displayed a statistically significant increase (P < 0.05). The increase in SNP-A, I?SN, and I?FH in the TSME group was significantly greater following treatment than in the RME group. The results support the use of the TSME to produce skeletal changes and dentoalveolar modification and to correct maxillary hypoplasia. It was also demonstrated that in patients with an anterior open bite, the use of the TSME is not contraindicated as the anterior vertical dimension did not increase significantly.     

Assessment of the relationship between the upper and lower arch changes with the opening of the expanding screw after the rapid maxillary expansion

Objective: The purpose of this study is to assess the relationship of the upper and lower arch dimension changes after the rapid maxillary expansion (RME) with the screw opening of the modified Hyrax type appliance. Materials and methods: Initial (T1) and final (T2) models of study of 63 children between 7 years and 6 months and 16 years and 5 months were performed. From these, 21 showed maxillary atresia and/ or posterior crossbite and were submitted to expansion and 42 children formed the control group .The appliance used in this work was the modified Hyrax appliance using the 7mm expanding screws "Dentarum". The measures of the upper intercanine and the upper and lower intermolar distances were performed in plaster models with the help of a "Digital Paquimeter". The opening of the appliance's screw was also assessed. Results: the RME provoked a statistically significant increase in the upper interdental distances and no statistic significance in the lower interdental distances, i.e. the change in the 16 - 26, 13 - 23 e 36 - 46 distance was of 5,85 mm, 5,31 and 0,34 mm respectively. The average opening of the expander screw, which was of 6,27 mm. Conclusion: the appliance's opening is related to the interdental distance changes, i.e. for each appliance's opening mm, a 0,94 variation in the upper intermolar distance, a 0,87 in the upper intercanine distance and 0,054 in the lower intermolar distance are provoked. KEY WORDS: Rapid maxillary expansion, posterior crossbite, transverse maxillary deficiency, dental arch.     

前方牵引联合快速扩弓矫治不同年龄骨性Ⅲ类错的硬组织变化

目的研究年龄对于前方牵引联合快速扩弓矫治效果的影响。方法将75例3~15岁的骨性Ⅲ类错患儿分成3组,在矫治前、矫治后分别摄X线头颅侧位片,对3组X线片进行头影测量分析,并进行统计学处理。结果3个年龄组矫治后均发生了显著的硬组织变化,且这些硬组织指标在不同年龄组差异有显著性。结论年龄对于前方牵引联合快速扩弓矫治效果有较为明显的影响,矫治后上颌骨以及下颌骨的位置均与年龄有关。     

Le Fort Ⅲ型截骨中位牵引成骨治疗成人面中份发育不全

目的:评价中位牵引成骨治疗成人面中份发育不全的疗效。方法:使用自行设计制作的颌骨牵引装置,在全麻手术下LeFortⅢ型截骨,后将牵引钩置入鼻底或梨状孔侧缘,从鼻孔引出,外部装置采用面弓或坚固外固定支架,对8例面中部凹陷畸形成年患者行前牵引,治疗前后拍摄定位头颅侧位片测量分析。结果:上颌中位前牵引治疗后,患者咬合关系和软组织侧貌改变明显,A点水平前移在9～14.5mm之间,面部上中下各部的前后关系协调,鼻梁及鼻下部挺拔,眼球突出度改进明显。结论:经梨状孔中位牵引成骨可有效矫治面中部发育不全,该牵引技术牵引力点适中,能够使面中份骨骼平衡前移;避免对牙齿牵引造成的不利改变。长期效果有待于进一步观察。     

Rapid maxillary expansion. Is it better in the mixed or in the permanent dentition?

The aim of this study was to compare the dentoskeletal effects of a modified acrylic-bonded rapid maxillary expansion (RME) device when it is used in the mixed and permanent dentitions. The study group consisted of 51 patients in the mixed and permanent dentition (26 girls and 25 boys) who underwent RME treatment. Group 1 was composed of 34 subjects in the mixed dentition (19 girls and 15 boys; mean age, 9.2 +/- 1.3 years). Group 2 consisted of 17 subjects in the permanent dentition (seven girls and 10 boys; mean age 12.7 +/- 1.2 years). Lateral and frontal cephalograms and upper dental casts were collected before treatment (T1), after treatment (T2), and after retention (T3). Intragroup and intergroup changes were evaluated by paired t-test and Student's t-test, respectively. In both groups after RME, the maxilla moved forward; mandible rotated posteriorly; facial height increased; nasal, maxillary, and maxillary intercanine and first molar widths increased; and the upper molars tipped buccally. Almost all these significant changes were stable at follow-up (T3). When overall (T1 - T3) differences were considered, upper molars tipped more, and the ANB angle increased less in the mixed dentition group compared with the permanent dentition group (P < .01). Within the limits of this study, the results suggest that the orthopedic effects of RME are not as great as expected at early ages, and it might be a better alternative to delay RME to early permanent dentition.