Complications associated with surgically assisted rapid palatal expansion without pterygomaxillary separation.

INTRODUCTION: The purpose of this retrospective clinical study was to evaluate the surgical complications associated with the surgically assisted rapid palatal expansion (SARPE) which does not involve pterygomaxillary separation (PMS). PATIENTS AND METHODS: A total of 40 (25 females, 15 males) skeletally mature patients, who had the diagnosis of maxillary transverse maxillary deficiency (TMD), were treated surgically under local or general anesthesia. The mean follow-up time was 6 months. RESULTS: Recorded perioperative and postoperative complications were discussed within the current literature. No serious complications were observed intraoperatively. Eight patients (20%) showed postoperative complications including neurosensory deficits, maxillary sinus infection, epistaxis, fistula formation and incisional dehiscence. DISCUSSION: Neurosensory deficits were the most common findings. The present findings suggest that minor complications were observed associated with SARPE without PMS. The technique may be performed safely also under local anesthesia.

Relationship between Orthodontic Treatment Plan and Goslon Yardstick Assessment in Japanese Patients with Unilateral Cleft Lip and Palate: One-stage vs. Two-stage Palatoplasty.

The present study targeted patients with unilateral cleft lip and palate (UCLP) undergoing either one - (Wardill technique) or two-stage palatoplasty (Perko technique). Correlations between Goslon Yardstick scores and orthodontic appliances used and whether an osteotomy was performed were investigated. No differences were observed between the two types of palatoplasty in terms of Goslon Yardstick scores. A palatal expander and protraction facemask were used in Phase I of orthodontic treatment. The palatal expander was selected for most patients with UCLP in Phase I, regardless of the surgical technique used. A protraction facemask was used in patients undergoing the Wardill procedure who had a Goslon Yardstick score placing them in Group 3 or 4. In contrast, a protraction facemask was used in patients undergoing the Perko procedure who had a Goslon Yardstick score placing them in Group 4. No significant differences were observed in the Goslon Yardstick scores yielded by either type of procedure. The Goslon Yardstick score in relation to whether an osteotomy was performed in Phase II as part of orthodontic treatment was determined, focusing on the relationship between that score and the palatoplasty method used. A protraction facemask was used in patients undergoing the Perko procedure, which eliminated the need for an osteotomy at a future date. However, a protraction facemask was also used in patients undergoing the Wardill option, and those patients were likely to require an osteotomy. In other words, the results suggest that the type of palatoplasty selected will determine the effectiveness of any orthodontic appliances used.

Effects of rapid maxillary expansion with six months of retention and no further orthodontic treatment / Efeitos da expansão rápida da maxila com 6 meses de contenção e sem posterior tratamento ortodôntico

Previous investigations addressing the long-term effects of rapid or slow expansion on the face and teeth involved the use of a orthodontic fixed appliance following expansion therapy. The present study evaluated changes in dentoskeletal aspects following rapid maxillary expansion (RME) and determine the stability of these changes over three years of follow up. Ten children with bilateral posterior crossbite were evaluated (experimental group). Dental casts and lateral cephalograms were evaluated prior to RME (T0) as well as three months (T1), one year (T2) and three years (T3) after RME. The measures were compared to a control group composed of 21 individuals using ANOVA and the Student's t-test (p > 0.05). Changes on the transverse plane revealed significant expansion of the upper dental arch three months after RME, stable after three years. Expansion at the cusp level was similar to that at the gingival level. No significant changes were found in the angular and linear cephalometric measures among T0, T1, T2 and T3, and in comparison to the control group (p > 0.05). We concluded that early RME produces stable transverse increases in the upper arch after three years without significantly altering sagittal and vertical dentoskeletal relationships, and neither inclined teeth.

A expansão rápida ou lenta da maxila seguida do uso de aparelhos ortodônticos fixos altera a face e os dentes. Este estudo avaliou as mudanças dentoesqueléticas após a expansão rápida da maxila (ERM) e determinou a estabilidade dessas mudanças em três anos de acompanhamento. Dez crianças com mordida cruzada posterior bilateral foram avaliadas (grupo experimental). Modelos de estudo e telerradiografias laterais foram avaliadas antes da ERM (T0), assim como três meses (T1), um ano (T2) e três anos (T3) após a ERM. As medidas foram comparadas às de um grupo controle composto de 21 pacientes por meio do teste ANOVA e teste t Student (p > 0,05). As mudanças no plano transversal revelaram uma expansão significante no arco superior três meses após a ERM, que se manteve estável após três anos. A expansão ao nível das cúspides foi similar à do nível gengival. Mas nenhuma diferença significante foi encontrada estre as medidas cefalométricas angulares e lineares ao longo dos períodos T0, T1, T2, e T3 e nem quando se comparou essas medidas às do grupo controle (p > 0,05). Conclui-se que A ERM precoce produz aumentos transversais estáveis no arco superior sem alterar significantemente as relações sagitais e verticais dentoesqueléticas e nem inclinar dentes.

Rapid-maxillary-expansion induced rhinological effects: a retrospective multicenter study.

Conventional dental-borne rapid maxillary expansion (RME) leads to a widening of the airways, followed by improved nasal breathing. Although combined skeletal-dental appliances are nowadays being inserted increasingly often and provide a force at the center of resistance in the nasomaxillary complex, no study exists so far that shows whether this treatment may improve the expansionary effect on the airways. In this study, low-dose computed tomography (CT) images from 31 patients (average age 14.63 ± 0.38 years) were examined retrospectively. Both records (T0 = before expansion and T1 = immediately after maximum expansion) were taken in a time interval of 25 days to avoid growth influence. Five patients were treated with Hyrax RME, 6 patients with Hybrid RME, and 20 patients with acrylic cap RME. The total airway volume increased highly significantly (mean +7272.6 mm(3); P < 0.001, power = 0.998), representing an average airway expansion of +11.54 % (2.35 %/mm activation). While the nasopharynx and oropharynx showed highly significant expansion (P < 0.000, power = 0.999), the airway at the laryngopharynx did not change significantly (P > 0.779, power = 0.05). Although the patients were significantly older in the Hybrid RME group (P = 0.006), the positive rhinological effects were comparable within all groups of different appliances (P > 0.316). Hybrid RME may, therefore, be an advisable procedure in patients with nasomaxillary impairment and pronounced patient's age.

Maxillary expansion therapy with plates featuring a transverse screw: implications of patient compliance with wear-time and screw activation requirements.

OBJECTIVE: The goal of the present work was to determine the influence of screw activation rates and electronically tracked wear times on transverse maxillary expansion with removable orthodontic appliances. METHODS: In all, 28 patients were included in an open prospective observational study covering approximately 6 months of maxillary transverse expansion. In each of these patients, the maxillary plate appliance used for treatment was fitted with a wear-time sensor to document wear time for the duration of the study. Patients were instructed to activate the transverse expansion screw in their plate appliance by 0.2 mm/week. The resultant gap-width increases were monitored with a caliper over three follow-up appointments scheduled at 2-month intervals. RESULTS: Largely linear increases in gap width due to screw activation were only noted within the first 4 months of treatment. The mean increases in gap width fell short of the values that were anticipated after calculations. Longer daily wear times were, on average, associated with larger gap widths. CONCLUSION: Treatment can be objectively monitored by referring to wear-time tracking and by measuring increases in gap width, thus, ensuring that the appliance fits well. In this way, the process can be customized to serve individual needs and to better utilize the full potential of therapy.

Nationwide survey of surgically assisted rapid maxillary expansion.

We aimed to gather data on the current practice of surgically assisted rapid maxillary expansion (SARME) in the UK. Surveys were posted in the mail to all members of the British Association of Oral and Maxillofacial Surgeons (n=379) and 166 (44%) responded. In the previous year 69 responders (42%) had done at least one SARME operation. The technique used by individual surgeons may be more experience-based than evidence-based, which leads to considerable variation.

Predicted versus executed surgical orthognathic treatment.

OBJECTIVES: This study aimed to analyse combined surgical-orthodontic treatment plans, compare them with the actual surgery performed, and define factors resulting in changes of the original plan during orthodontic pre-surgical preparation. STUDY DESIGN: The clinical files of 312 orthognathic surgery patients, operated between January 2008 and December 2010, were retrospectively reviewed. Of these 312 patients, 129 had a bimaxillary operation. One hundred sixty patients had osteotomy of the lower jaw only and 23 had osteotomy of the upper jaw only. Factors analysed in the study include Angle Class malocclusion, patient sex, and age. Lip-to-incisor relationship, overjet, overbite and midline deviations of the upper and lower jaw were recorded. Effects of surgical assisted rapid palatal expansion (SARPE) on the eventual surgery were also investigated. Reasons for changing the original treatment plan at the time of the finished pre-surgical-orthodontic alignment were analysed. RESULTS: The original treatment plan was changed in 42 of the 312 patients (13.5%). Changes occurred generally in case of a larger interval between set-up of the first treatment plan and the eventual operation (average 22.4 versus 16.4 months for patients with changed versus unchanged treatment plan, respectively). All Class I patients had surgery performed as planned. Class III patients had a significantly higher rate of altered treatment plan (27.3%) than Class II patients (7.6%). More men (52.4%) saw their treatment plan changed, although there were more women than men in the study population (59.6 versus 40.4%). CONCLUSION: One in seven patients (13.5%) had a different operation than was planned at the start of treatment. Class III patients with small overjet and overbite commonly have a treatment plan for a monomaxillary operation that, after decompensation, needs to be adapted to a bimaxillary operation.

Changes in nasal air flow and school grades after rapid maxillary expansion in oral breathing children

Objective: To analyse the changes in nasal air flow and school grades after rapid maxillary expansion (RME) in oral breathing children with maxillary constriction.Material and Methods: Forty-four oral breathing children (mean age 10.57 y) underwent orthodontic RME with a Hyrax screw. Forty-four age-matched children (mean age 10.64 y) with nasal physiological breathing and adequate transverse maxillary dimensions served as the control group. The maxillary widths, nasal air flow assessed via peak nasal inspiratory flow (PNIF), and school grades were recorded at baseline, and 6 months and one year following RME. Results: After RME, there were significant increases in all the maxillary widths in the study group. PNIF was reduced in the study group (60.91 ± 13.13 l/min) compared to the control group (94.50 ± 9.89 l/min) (P < 0.000) at the beginning of the study. Six months after RME, a significant improvement of PNIF was observed in the study group (36.43 ± 22.61). School grades were lower in the study group (85.52 ± 5.74) than in the control group (89.77 ± 4.44) (P < 0.05) at the baseline, but it increased six months after RME (2.77 ± 3.90) (P < 0.001) and one year later (5.02 ± 15.23) (P < 0.05). Conclusions: Nasal air flow improved in oral breathing children six months and one year after RME. School grades also improved, but not high enough to be academically significant (AU)

Life-threatening haemorrhage after 750 Le Fort I osteotomies and 376 SARPE procedures.

This study assessed the incidence, presenting symptoms, diagnosis, and management of patients with life-threatening postoperative haemorrhage after total Le Fort I osteotomy and surgically assisted rapid palatal expansion (SARPE). The medical records of 750 consecutive Le Fort I osteotomies and 376 consecutive SARPEs, both of which involved pterygomaxillary separation with a curved osteotome and a mallet, were analysed prospectively. Two cases of life-threatening haemorrhage were observed in the Le Fort I osteotomy group, both initiated on postoperative day 7. Anterior and posterior nasal packing were successful in one patient; the other required two embolizations for bleeding control (incidence of life-threatening postoperative haemorrhage: 2/750; confidence interval: 0.03-0.96%). In the SARPE group, one brisk epistaxis on the first postoperative day was controlled with anterior and posterior nasal packing under general anaesthesia. This haemorrhage was not considered life threatening (incidence of life-threatening postoperative haemorrhage: 0/376; confidence interval: 0-0.98%). In no case could the source of bleeding be established during re-explorative surgery or during diagnostic arteriography. The authors conclude that life-threatening haemorrhage is an exceptional finding after Le Fort I osteotomy; the observed incidence was 2/750, and life-threatening haemorrhage was not observed after SARPE in this series, despite the use of identical pterygomaxillary separation.

Complications following surgically assisted rapid palatal expansion: a retrospective cohort study.

PURPOSE: To examine the prevalence of complications and characterize the associated clinical findings in patients undergoing surgically assisted rapid palatal expansion (SARPE). MATERIALS AND METHODS: A retrospective evaluation was conducted of all patients who underwent SARPE from January 2004 through December 2008 at Kaiser Permanente Oakland Medical Center. Medical records were abstracted, and demographic factors and relevant comorbidities were identified. Clinical features of patients with complications (surgical and/or dental) after SARPE were characterized. RESULTS: One hundred thirty-one patients comprised the study sample and 11 patients were excluded. Of the remaining 120 patients (median age, 29.5 yrs; interquartile range, 22.0 to 39.0 yrs), 51.7% were women, 41 developed at least 1 complication, 33 had surgical complications, 18 had dental and/or periodontal problems, and 10 developed both surgical and dental or periodontal problems. Asymmetric and/or inadequate expansion was the most frequent surgical complication, found in 13.3% of the study cohort, and gingival recession (8.3%) was the most common dental complication. Two patients developed catastrophic periodontal bone defects resulting in loss of the central incisors; these patients had eccentric interdental osteotomies that caused separation of the bone from the root surface of the central incisors followed by postoperative osteotomy site infections. CONCLUSIONS: Overall, the present findings suggest that, although major complications after SARPE were rare, asymmetric or inadequate expansion and dental and/or periodontal problems primarily involving the central incisors accounted for most complications. Future prospective and long-term follow-up studies are needed to identify individual risk factors that may predispose patients to adverse outcomes after SARPE.

Three-dimensional finite element analysis of stress distribution and displacement of the maxilla following surgically assisted rapid maxillary expansion.

PURPOSE: The aim of this study was to investigate the displacement and stress distributions during surgically assisted rapid maxillary expansion under different surgical conditions. MATERIALS AND METHODS: 3-dimensional finite element model of a maxilla with a Hyrax appliance was constructed and an expansion force of 6000 grams was applied using the expansion screw. According to the surgical procedures, 5 groups including a control group without surgery (Group I) were simulated. The experimental groups were as follows; Group II (Le Fort I osteotomy), Group III (Le Fort I osteotomy and paramedian osteotomy), Group IV (Le Fort I osteotomy and pterygomaxillary separation), and Group V (Le Fort I osteotomy, paramedian osteotomy, and pterygomaxillary separation). RESULTS: Displacement of the maxilla gradually increased from Group 1 to Group 5 in all three planes of space, indicating that combination of the Le Fort I osteotomy with paramedian osteotomy and pterygomaxillary separation produce greatest displacement of the maxilla. By surgical relief, the stress exerted on anchor teeth was significantly reduced. CONCLUSION: The results suggested that the combination of Le Fort I and paramedian osteotomy with pterygomaxillary separation is an effective procedure for increasing the expansion of the maxilla with lower side effects caused by excessive stresses around the anchor teeth.

Closer look at the stability of surgically assisted rapid palatal expansion.

PURPOSE: To assess the amount of dental and skeletal expansion and stability after surgically assisted rapid maxillary expansion (SARPE). PATIENTS AND METHODS: Data from 20 patients enrolled in this prospective study were collected before treatment, at maximum expansion, at the removal of the expander 6 months later, before any second surgical phase, and at the end of orthodontic treatment, using posteroanterior cephalograms and dental casts. RESULTS: With SARPE, the mean maximum expansion at the first molar was 7.48 +/- 1.39 mm, and the mean relapse during postsurgical orthodontics was 2.22 +/- 1.39 mm (30%). At maximum, a 3.49 +/- 1.37 mm skeletal expansion was obtained, and this expansion was stable, such that the average net expansion was 67% skeletal. CONCLUSION: Clinicians should anticipate a loss of about one third of the transverse dental expansion obtained with SARPE, although the skeletal expansion is quite stable. The amount of postsurgical relapse with SARPE appears quite similar to the changes in dental-arch dimensions after nonsurgical rapid palatal expansion, and also quite similar to dental-arch changes after segmental maxillary osteotomy for expansion.

A comparison of dental arch forms between Class II Division 1 and normal occlusion assessed by euclidean distance matrix analysis.

INTRODUCTION: The purpose of the study was to use euclidean distance matrix analysis to compare dental arch forms between subjects with Class II Division 1 malocclusions and normal occlusions. METHODS: The sample consisted of 60 subjects with Class II Division 1 malocclusions and 60 subjects with normal occlusions, all between 13 and 17 years of age. Fourteen landmarks, corresponding to cusp tips and incisor edges, were identified on the dental casts with a 3-dimensional measuring machine. All possible linear distances between pairs of landmarks in an arch were computed, and arch-form differences between Class II Division 1 and normal-occlusion subjects were tested by euclidean distance matrix analysis. RESULTS: In both sexes, the maxillary arches of the Class II Division 1 subjects were larger than the arches of the normal-occlusion subjects (1.8% and 2.7% larger for girls and boys, respectively), and arch shape was also significantly different (P < .001). The posterior teeth contributed to the shape difference between 2 groups more than the anterior teeth, moreover the main factor was narrow maxillary posterior arch width in the Class II Division 1 subjects. The mandibular arches of the Class II Division 1 subjects were also slightly larger, and arch shape was not significantly different regardless of sex. CONCLUSIONS: Expanding the maxillary posterior arch width in Class II Division 1 subjects might be an important method to harmonize maxillary and mandibular arch forms.

Clinical profile of rapid maxillary expansion--outcome of a national inquiry.

BACKGROUND: Rapid maxillary expansion (RME) is a therapeutic orthodontic option with a long history, and there are many reports in the literature reporting widely divergent results concerning the appliance efficacy and many different treatment protocols. We aimed to evaluate the treatment protocols and clinical experiences with RME via a national inquiry of orthodontists to identify the status quo of RME in clinical daily routine. METHOD: Within the framework of an anonymous questionnaire, 2003 orthodontists and members of the German Orthodontic Society (DGKFO) were asked to report on their clinical experiences with RME. The standardized questionnaire covered clinical indications, dentition period at the time of insertion, mode of activation, retention time, observed side effects, and the reasons for requiring surgical assistance. RESULTS: The data from 487 questionnaires could be evaluated. The only indication for RME named by a large majority of responders was transversal maxillary deficiency. The average extent of the transversal deficiency amounted to 5.29 +/- 2.25 mm (median 5 mm). Most orthodontists (87.7%) employed RME in the permanent dentition of adolescents; it was significantly less frequently applied in the primary dentition or adults. Answers regarding the mode of activation varied greatly. The most frequent mode of activation was "1-2 activations a day" independent of the dentition period. 64.5% of the orthodontists reported buccal tipping of the anchorage teeth. No correlation was detected between mode of activation, time of insertion and observed side effects. 60% of the orthodontists reported a retention period of between 3 and 6 months (median 4.5 months). With an average age of 19.28 years, 79.3% assessed chronological age as a limiting factor for conventional RME. It was not possible to identify a homogeneous diagnostic procedure for the indication of surgical assistance. CONCLUSIONS: Although RME has a long clinical history, no standardized treatment protocols exist. Randomized clinical trials are necessary to make clear-cut clinical recommendations on the use of RME, as required by the tenets of evidence-based medicine and quality assurance.

Frequency of and complications in the use of RPE appliances--results of a survey in the Federal State of Hesse, Germany.

AIM: A questionnaire was sent to orthodontists with private practices in the German State of Hesse to obtain information about the frequency of rapid palatal expansion and complications during treatment with rapid palatal expansion appliances (RPE-A). MATERIAL AND METHOD: A series of questions therein inquired as to the types of RPE-As used, their activation rhythm, the extent and the duration of the active expansion and retention; what their age limit was, starting from when surgical assistance was deemed necessary. Another series of queries concerned any technical and medical complications observed. RESULTS: The most frequently used type was the Hyrax screw (75%) soldered to bands. Technical problems arose with all applied indicated types. Although the answers to the first series of questions showed great variance, the majority of the orthodontists activated the screw twice a day (range 1-6 times a day) by a quarter turn for 2-3 (range 1-12) weeks. The retention phase amounted to 12 (range 4-26) weeks and the age limit for the indication of a surgical intervention was on average 17 years, with a range of 10-35 years. Medical complications such as pain and decubitae were reported by a third of the inquired offices, a non-opening suture was observed in one of every five practices. This meant that 1.7% of the sutures failed to open, and tooth tilting and rarely, extreme root resorptions and/or bone dehiscences were observed. Solid carious lesions were observed in one case after removal of an adhesive RPE. Extraoral changes such as those in the nose were reported by one in every ten practices. CONCLUSIONS: The RPE represents a common treatment means during which side effects are often temporary and permanent damages rather rare. It is important to inform the patient about both positive effects and possible complications, in particular pain and extraoral changes.

Three-dimensional assessment of morphologic changes of the maxilla: a comparison of 2 kinds of palatal expanders.

Previous studies of the morphologic changes of the maxilla after palatal expansion have used 2-dimensional methodologies. In the present study, we used a 3-dimensional surface laser scanning technique and computerized cast analysis, in addition to analysis of anteroposterior cephalograms, to assess the morphologic changes of the palate by 2 kinds of expanders: tissue borne (Haas; n = 9) and tooth borne (Hyrax; n = 10). Cast analysis demonstrated that, although all patients started treatment with similar malocclusion, treatment outcomes were different depending on the appliance used. Both appliances generated maxillary expansion (ie, improved mean surface area, mean intermolar linear distance, and mean perimeter) (P <.05). However, the appliances performed differently to achieve the final expansion. Haas appliances demonstrated a greater orthopedic movement (ie, improvement of the mean interpalatal distance) (P <.05), and Hyrax appliances demonstrated dentoalveolar expansion by increasing the mean palatal angulation of the alveolus (P <.05). Anteroposterior cephalometric analysis showed that both appliances increased mean maxillary width and mean intermolar distance significantly (P <.05). On the other hand, differences in nasal cavity width and upper incisal apex distance were not statistically significant (P >.05). This new 3-dimensional methodology proved useful for comparing treatment outcomes by evaluating the morphologic changes induced by palatal expansion and generated a better visualization of these outcomes.

A histologic and histomorphometric evaluation of pulpal reactions following rapid palatal expansion.

The aim of this study was to investigate the effects of the heavy forces exerted by the rapid palatal expansion (RPE) appliance on the pulpal tissue of anchor premolar teeth and to evaluate these effects by histologic and histomorphometric methods. Materials consisted of 34 sound upper premolars, extractions of which were required as part of orthodontic treatment. Twenty-three teeth were extracted after RPE; the remaining 11 teeth, which had not undergone any orthodontic force, were taken as controls. After extraction, the teeth were prepared for histologic examination under light microscopy. Histomorphometric measurements were performed by using image analysis. The data gained were statistically evaluated by nonparametric tests. The null hypothesis was that there was no difference between pulpal tissues of control and test teeth with respect to different durations of RPE. Our results reveal that the null hypothesis was rejected. Of the parameters evaluated, vessel area and minimum and maximum vessel diameters showed significant differences among the groups. Especially the difference between the control and 3-month groups had marked statistical significance. In conclusion, forces applied by RPE appliances caused an adaptive vascular tissue response, as well as fibrotic changes, in the "affected" upper premolars.

Follow-up control of patients with unilateral posterior cross-bite treated with expansion plates or the quad-helix appliance.

The aim of this study was to evaluate the long-term stability of the occlusion after correction of posterior cross-bite with either a removable expansion plate or a quad-helix appliance and to compare the transversal development of the jaws in the plate group, the quad-helix group and a control group. At the start of treatment there were 22 children in each of the treated groups. Two children in the plate group and 1 child in the quad-helix group discontinued the treatment. Two children treated with the quad-helix appliance and 1 child in the plate group could not be reached for the follow-up registration, so the collective finally consisted of 30 boys and 27 girls: 19 subjects in the plate group, 19 in the quad-helix group and 19 controls. The treatment groups were studied with the help of plaster models before treatment, immediately after treatment and at the last registration about 5.5 years after treatment. The control group was studied with the help of plaster models on 2 occasions, at the mean age of 8.8 years and 15.9 years respectively. This was about the same age as the first and the last registrations in the treatment groups. In all children, the posterior cross-bite was corrected by the end of the treatment. At the last registration, the corrected posterior cross-bite had relapsed in 1 child in the plate group and in 3 children in the quad-helix group. The degree of expansion was similar for both groups. The mean treatment time was longer in the plate group than in the quad-helix group: 12.5 months and 7.7 months respectively. Despite a transversal expansion in the treatment groups, the width of the maxillary dental arch did not reach the mean width in the control group, and even at the last registration the width of the maxillary dental arch was significantly greater in the control group than in the treated groups. The conclusions of this study are: 1. The long-term treatment effect in children with posterior cross-bite was somewhat better when they were treated with the removable expansion plate in comparison with treatment with the quad-helix appliance. 2. Both immediately after treatment and at the last registration 5.5 years later, the width of the maxillary dental arch was significantly greater in the control group than in the plate group or the quad-helix group while the width of the mandibular dental arch was equal in all 3 groups.

Maxillary protraction and chincap appliance treatment effects and long-term changes in skeletal class III patients.

The purpose of this study was to investigate the orthopedic effects of combined maxillary protraction appliance (MPA) and chincap therapy on growing Japanese girls and the posttreatment changes after growth is complete. To estimate the actual effects of treatment and posttreatment changes, we used a series of templates that had been constructed from semilongitudinal data of Japanese girls with normal occlusion. During treatment, forward movement of the maxilla with counterclockwise rotation, and backward and downward movement of the mandible with clockwise rotation and growth retardation were observed. The forward movement of the maxilla persisted until growth was complete. During the posttreatment period, the mandible maintained its improved position but showed excessive growth, which could be a rebound change. These results indicate that combined MPA and chincap treatment is effective for correcting skeletal Class III malocclusion.