Maxillary Protraction Appliance Research Articles

Finite element and clinical analyses of effects of a new intraoral device (VomPress) combined with extraoral RAMPA on improving the overjet of craniofacial complex

This research intends to investigate the effects of a new intraoral device, VomPress, combined with a Right Angle Maxillary Protraction Appliance (RAMPA) extraoral device on the treatment of maxillary hypoplasia. To this end, finite element (FE) method has been employed and a skull model, including all sutures, has been investigated. In addition, the effects of VomPress combined with RAMPA on a seven-year-old girl with the malocclusion and other side problems were monitored. The results of both FE simulations and the clinical data revealed that VomPress combined with RAMPA effectively improved the malocclusion and straight neck problem by creating more space in the patient’s mouth and anterosuperior protraction effects.

Early treatment of Class III malocclusion by maxillary protraction facial mask: effects on craniofacial structures and upper airway dimensions

The aim of our study was to evaluate the effect of treatment with a maxillary protraction appliance on the development of the craniofacial structures and to describe the correlation between the skeletal changes and the sagittal airway dimension associated with tongue, soft palate, and hyoid bone position in skeletal Class III children. A total of 40patients with Class III malocclusions were evaluated by the use of lateral cephalograms. Pretreatment and posttreatment cephalometric radiographs were analyzed; linear and angular measurements were performed by the same orthodontist. The effect of treatment with a maxillary protraction appliance on the development of the craniofacial structures were evaluated by Student's T test and the correlation between treatment changes in craniofacial morphology and those in upper airway, tongue, soft palate, and hyoid position was evaluated by Pearson's correlation test. A significant increase in maxillary forward growth, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. The statistical analysis revealed that maxillary growth had a significant positive effect on the superior upper airway sagittal dimension. The nasopharyngeal airway dimensions can be improved in the short term with maxillary protraction in skeletal Class III children.

Anterosuperior protraction of maxillae using the extraoral device, RAMPA; finite element method

This paper presents a boosting effect against gravity by analyzing the displacement and stress distribution of craniofacial structures due to the protraction of the extraoral device, the Right Angle Maxillary Protraction Appliance(RAMPA) system, including semi-rapid maxillary expansion (sRME) using the finite element method. In addition, a patient case was illustrated and compared with the results calculated from a simulation. The results from the finite element method were obtained for 0.5 mm activation using the screw of the intraoral device, gHu-1. This study reveals that RAMPA rotates the patient’s maxilla and mandible in the forward direction and forces them to move forward and upward.

Assessment of the effect of maxillary protraction appliance on pharyngeal airway dimensions in relation to changes in tongue posture

Literature is controversial in regard with alterations in pharyngeal airway dimensions subsequent to maxillary protraction. The correlation between maxillary protraction and sagittal airway dimension was investigated in association with tongue and soft palate position in skeletal Class III children. The results were compared with those of an untreated Class III and a Class I malocclusion control group. In this cross-sectional study pre- and post-treatment cephalometric radiographs of 19 Class III patients (6 males, 13 females; mean age, 7.93 ± 0.96 years) treated with facemask were analyzed. The correlation between treatment changes in craniofacial morphology and those in the upper airway, tongue, and soft palate was evaluated. These results were compared with those of a group of 16 Class I malocclusion patients (1 male, 15 females; mean age, 7.31 ± 0.7 years) and a group of 15 untreated Class III patients (4 males and 11 females; mean age, 7.46 ± 0.1 years). A paired t-test, the Shapiro-Wilk test and Mann-Whitney U-test was used. The level of significance was established as P < 0.05. Nasopharyngeal airway measurements PNS-ad1 and PNS-ad2 significantly increased by 2 mm and 2.1 mm, respectively. Statistical analysis revealed that maxillary protraction had a positive relationship with PNS-ad1 and PNS-ad2. Nasopharyngeal airway dimensions can be improved in the short term with maxillary protraction in skeletal Class III children.

Evaluation of maxillary central incisors on the noncleft and cleft sides in patients with unilateral cleft lip and palate-Part 1: Relationship between root length and orthodontic tooth movement.

To measure the root lengths of maxillary central incisors (U1) and evaluate the relationship among U1 root length, tooth movement, and type of treatment appliance in patients with unilateral cleft lip and palate over a long-term follow-up period. Occlusal radiographs of 30 patients with unilateral cleft lip and palate, acquired less than 6 months before secondary alveolar bone grafting (SBG, T1) and after edgewise treatment (T2), were measured for U1 root length (R1 and R2, root lengths at T1 and T2, respectively). Frontal and lateral cephalometric radiographs acquired at eruption of U1 (T0), T1, and T2 were evaluated to determine the inclination and position of U1. The average values of R1 and R2 on the cleft side were significantly lower than those on the noncleft side. Frontal cephalometric analysis revealed that the horizontal distance of the root apex from the median vertical line at T0 on the cleft side was significantly smaller than that on the noncleft side and was correlated with short U1 root length on the cleft side. On the other hand, R1 in patients treated with maxillary protraction appliances between T0 and T1 was significantly shorter than that in patients without maxillary protraction appliances. However, none of the changes in cephalometric measurements were correlated with root length. In patients with unilateral cleft lip and palate, the short root length of cleft-adjacent central incisors might be associated with the horizontal position of the root apex. In addition, orthodontic treatment with a maxillary protraction appliance before secondary alveolar bone grafting might be associated with short U1 root length.

Maxillary growth after maxillary protraction: Appliance in conjunction with presurgical orthopedics, gingivoperiosteoplasty, and Furlow palatoplasty for complete bilateral cleft lip and palate patients with protruded premaxilla

In bilateral cleft lip and palate (BCLP) with premaxillary protrusion, a good outcome with adequate maxillary development is difficult to achieve. The purpose of this article is to evaluate the maxillary growth after using presurgical orthopedics (PSO), gingivoperiosteoplasty (GPP), Furlow palatoplasty, and maxillary protraction appliance (MPA) for BCLP with premaxillary protrusion. Seven patients with complete BCLP with premaxillary protrusion were treated by PSO, cheiloplasty, GPP, and Furlow palatoplasty. MPA was used as part of the protocol for 6 months to 1 year for postoperative retardation of maxillary growth cases. Maxillary growth was evaluated by cephalometric analysis at 4 and 10 years of age, and bone formation at the alveolar cleft was evaluated by computed tomography (CT) imaging at 5 years of age. At 4 years of age, three of seven patients had apparent retardation of maxillary growth. The maxillary growth at 10 years of age was equivalent to the average value of normal Japanese after using MPA in three cases. At 5 years of age, only two of seven patients showed sufficient bone formation at the alveolar cleft to avoid alveolar bone grafting (ABG). Subsequently, ABG was performed in five patients. Although three of seven patients had apparent crossbite at 4 years of age, the maxillary growth of all patients at 10 years of age was approximately equivalent to the average value of normal Japanese after using MPA. A treatment protocol based on PSO, GPP, Furlow palatoplasty, and MPA may be an option, but long-term growth is unknown.

A study on the relationship between maxillary protraction treatment and changes of nasomaxillary complex facial soft tissue of children with skeletal Class m malocclusion

Objective To investigate nasomaxlllary complex facial soft tissue changes after the treatment with maxillary protraction appliance with skeletal Class Ⅲ malocclusion with a retruded maxilla.Methods Thirty growing subjects with skeletal Class Ⅲ malocclusions with maxillary retrognathism were selected and treated by facial mask(male 15,female 15,with an average age of 10.5).They were given a maxillary protraction treatment with face mask for 6-8 months.Cephalometric measurements about nasomaxillary complex soft tissue changes were analyzed to draw the statistic conclusion.Results After maxillary protraction treatment,PraY,nasofrontal angle,As-Y,UL-Y,UL-E,S-Ns-Sn increased (P ＜ 0.01) ; M-Y increased (P ＜ 0.05) ; LL-E,PosY,nasolabial angle decreased (P ＜ 0.05).There were no significant differences in the Ns-Y and columella-tip angle.Conclusion After maxillary protraction treatment,nasomaxillary complex area becomes more marked.Both the nasomaxillary complex soft tissue and lower facial profile are dramatically improved.The combining effect of these two changes results in a more harmony profile. Key words: Maxillary protraction; Maxillary retrognathism; Skeletal Class Ⅲ malocclusion; Nasomaxillary complex; Facial soft tissue

Correlation between skeletal changes by maxillary protraction and upper airway dimensions

To describe the correlation between the skeletal changes induced by maxillary protraction treatment and the sagittal airway dimension associated with tongue, soft palate, and hyoid bone position in skeletal Class III children. Twenty Class III patients (5 boys, 15 girls; mean age, 9.4 ± 1.8 years) treated with a maxillary protraction appliance were included in this study. Pretreatment and posttreatment cephalometric radiographs were analyzed; linear and angular measurements were performed by an expert orthodontist. The correlation between treatment changes in craniofacial morphology and those in upper airway, tongue, soft palate, and hyoid position was evaluated by Pearson's correlation analysis. A significant increase in maxillary forward displacement, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. Simultaneously, nasopharyngeal airway measurements PNS-ad1 and PNS-ad2 significantly increased by 1.4 mm and 1.9 mm, respectively. A correlation analysis revealed that maxillary protraction had a positive relationship with PNS-ad1 and PNS-ad2. The nasopharyngeal airway dimensions can be improved in the short term with maxillary protraction in skeletal Class III children.

Late Growth Period Orthopedic Therapy Versus Bimaxillary Surgery for Correction of Skeletal Class III

To compare the effects of late orthopedic therapy with orthognathic surgery in skeletal class III cases. The subjects of the study were divided into 2 groups. Group 1 comprised 15 patients (8 females and 7 males) with a mean age of 14 years 6 months (range, 12 y 10 mo to 15 y 6 mo) and treated with maxillary expansion and a modified maxillary protraction appliance (MMPA). Group 2 comprised 11 patients (6 females and 5 males) treated with bimaxillary surgery (BMS) with a mean age of 23 years (range, 18 y 2 mo to 28 y 4 mo). Lateral cephalometric films were taken before (T1) and after orthopedic therapy (T2) in the MMPA group and before surgery (T1) and after fixed orthodontic therapy (T2) in the BMS group. Study groups were compared by analysis of variance and Tukey tests at the beginning and at the end of the treatment. Maxillary forward displacement (P < 0.01) and the increase in ANS-Me distance (P < 0.05) were higher in the BMS group than in the MMPA group. The mandible exhibited significant posterior rotation in MMPA group (P < 0.01). Mandibular effective length decreased in the BMS group and increased in the MMPA group. Soft tissue profile (G-Sn-Pg) improved in both groups (P < 0.05) and labiomental angle reduced in the BMS group, whereas an increase was observed in the MMPA group. Orthognatic surgery can be more effective in patients with increased mandibular length, more anteriorly positioned mandibles, and increased vertical dimensions.

Treatment of a young adult with Class III malocclusion using a modified mini maxillary protractor: a case report

We describe the treatment of a young adult male (aged 14 years 9 months) with Class III malocclusion using a mini maxillary protraction appliance, and discuss the results. The patient was treated with an acrylic cap splint-type expander and a modified maxillary protractor until a positive overjet was achieved. Edgewise fixed appliances were used to align the teeth. The treatment resulted in Class I molar occlusion, an ideal overjet, overbite and incisor angulation. A Class I molar relationship was achieved after 6 months of treatment, and the total treatment time was 1 year 6 months. Modified maxillary protractor treatment is effective for correcting skeletal Class III malocclusion.

Maxillary Protraction Appliance Effect on the Size of the Upper Airway Passage

To test the hypothesis that maxillary protraction appliances (MPA) have no effect on the size of the upper airway passage and craniofacial structures in adolescent patients. Twenty patients (5 male and 15 female; mean age 11.5 years) with skeletal Class III malocclusion were included in this study. The records of all patients who had maxillary protraction treatment and had lateral head radiographs taken before and after their protraction treatments were obtained from the files of treated cases. Treatment changes were determined by means of linear, angular, and area measurements. Data were analyzed statistically by means of paired t-test and correlation analysis. Significant increases were observed in the width and area of the pharyngeal airway. Significant increases also occurred in the sagittal growth of the maxilla, while a clockwise rotation and inhibition of sagittal growth were observed in the mandible. The hypothesis was rejected. The size of the upper airway can be increased by means of MPA application.

Effects of treatment with a combined maxillary protraction and chincap appliance in skeletal Class III patients with different vertical skeletal morphologies

Several cephalometric studies and case reports have described the effects of treatment with a maxillary protraction appliance (MPA) and chincap appliance. The purpose of this investigation was to identify differences in the response to treatment with a combined MPA and chincap in skeletal Class III patients with different vertical skeletal morphologies: short- (low mandibular plane angle) and long- (high mandibular plane angle) face types. The cephalograms used in this study were of 42 Japanese girls at the beginning of treatment (T0, mean age 10.1 years) and at removal of the appliance (T1, mean age 11.5 years). The subjects were divided into two groups (short and long face) according to the inclination of the mandibular plane at T0. Total anterior face height, upper and lower face height, occlusal plane, and gonial angle were significantly larger in the long-face group at T0. In both groups, significant increases in SNA, maxillary size (A'-Ptm'), and ANB were noted during treatment. Compared with the long-face group, the short-face group showed greater forward displacement and size increment of the maxillary body, while there were no significant differences in changes in mandibular size or position between the two groups. These results indicate that the vertical dimensions of the craniofacial skeleton are important factors in the orthopaedic effects of a MPA and chincap and the prognosis for skeletal Class III patients.

Prediction of post-treatment outcome after combined treatment with maxillary protraction and chincap appliances

The aims of this study were to identify differences in the initial skeletal morphology between successful and unsuccessful groups and to establish a novel method for predicting the final outcome of treatment with a maxillary protraction appliance (MPA) and chincap. The cephalograms used in this study were taken from 32 Japanese girls (mean age 10.2 years) with a Class III malocclusion at the beginning of treatment with an MPA and chincap (T1), at removal of the appliance (T2), and during the final post-treatment period (T3). The subjects were divided into two groups according to the treatment outcome at T3. Lower face height (ANS-Me), total face height (N-Me), ratio of face height (ANS-Me/N-ANS), maxillary position, mandibular plane and gonial angle at T1 were all significantly larger in the unsuccessful group, compared with the successful group. Discriminant analysis indicated that lower face height and gonial angle were significant determinants for distinguishing between the two groups at T1. From T1 to T2, while the anterior displacement of the maxilla was almost the same in the two groups, SNB decreased by 1.6 degrees in the successful group and 0.4 degrees in the unsuccessful group. After orthopaedic treatment, a second phase of treatment with a multibracket system was performed (T2 to T3). From T2 to T3, SNA increased by 0.4 degrees in the successful group and decreased by 0.7 degrees in the unsuccessful group. These results indicate that the vertical dimensions of the craniofacial skeleton are important for predicting the prognosis of skeletal Class III patients treated with a MPA and chincap and that the discriminant formula established in this study is effective in predicting the final treatment outcome.

Effects of maxillary protraction on craniofacial structures and upper-airway dimension.

This study was conducted to examine the effect of treatment with a maxillary protraction appliance on the development of the craniofacial structures and upper-airway dimensions. A total of 25 patients (mean age: 9.8 years) with Class III malocclusions were evaluated by the use of lateral cephalograms. A significant increase in maxillary forward growth, inhibition of mandibular forward growth, and clockwise rotation of the mandible were observed. The maxillary incisors were significantly proclined and the mandibular incisors significantly retroclined. A multiple-regression analysis revealed that maxillary growth had a significant positive effect on the superior upper-airway dimension. These findings indicate that the superior upper-airway dimension can be altered during maxillary protraction.

Treatment effects of maxillary protraction appliance : Effects on Wits appraisal and its related structures

Treatment effects of maxillary protraction appliance : Effects on Wits appraisal and its related structures

Post-treatment changes after maxillary protraction appliance and their factors

Post-treatment changes after maxillary protraction appliance and their factors

Clinical Considerations in the Use of Maxillary Protraction Appliance in Cleft Lip and/or Palate Patients with Particular Emphasis on the Timing and Type of Protraction

Clinical Considerations in the Use of Maxillary Protraction Appliance in Cleft Lip and/or Palate Patients with Particular Emphasis on the Timing and Type of Protraction

Morphological changes on growing patients after removal of maxillary protraction appliance

Morphological changes on growing patients after removal of maxillary protraction appliance

Treatment effect of maxillary protraction appliance on unilateral cleft lip and palate patients

Treatment effect of maxillary protraction appliance on unilateral cleft lip and palate patients

Biomechanical effects of maxillary protraction on the craniofacial complex

The deformational effects on the human skull resulting from maxillary protraction were examined by means of strain gauges and displacement transducers. A maxillary protraction appliance was used that included a reverse headgear attached to the maxillary first molars. The protraction forces that were applied to this appliance were parallel to the occlusal plane at the following locations: (1) the height of the maxillary arch, (2) 5 mm above the palatal plane, and (3) 10 mm above the Frankfort horizontal plane. The results indicated that (1) protraction forces at the level of the maxillary arch produced an anterior rotation and forward movement of the maxilla, (2) protraction forces 10 mm above the Frankfort horizontal plane produced a posterior rotation of the maxilla with a forward movement of nasion, and (3) protraction forces 5 mm above the palatal plane produced a combination of parallel forward movement and a very slight anterior rotation of the maxilla. Moreover, constriction on the anterior part of the palate occurred in all cases.