Rapid Palatal Expansion Appliance Research Articles

Skeletal and dentoalveolar changes in the transverse dimension using microimplant-assisted rapid palatal expansion (MARPE) appliances

Conventional rapid palatal expansion (RPE) has been proven to be a reliable treatment for correcting transverse maxillary deficiency in young patients. However, side effects including dental tipping and risk of periodontal problem limited its application to young patients after the pubertal growth spurt. Surgically assisted rapid palatal expansion (SARPE), a supplement to RPE, could be applied in skeletally mature patients. However, SARPE was an invasive method, and the morbidity, risks and cost related to surgical treatment might discourage many adult patients. The use of Microimplant-Assisted Rapid Palatal Expansion (MARPE) appliance, which can potentially avoid surgical intervention, is gaining popularity in treatment of maxillary transverse deficiency (MTD) in young adolescent patients. However, the literature on the skeletal and dentoalveolar changes with this appliance is scarce. To evaluate the immediate skeletal and dentoalveolar changes in the transverse dimension with the maxillary skeletal expander (MSE), a MARPE appliance with hybrid anchorage, using cone-beam computed tomography (CBCT). Twenty-two patients (11 males and 11 females, mean age 14.97 ± 6.16 years) with transverse maxillary deficiency were treated using the MSE (Biomaterials Korea, Inc., Seoul, Korea). The appliance consisted of a central expansion screw that were welded to four tubes that served as guides for microimplant placement. The microimplants were 1.8 mm in diameter and 11 mm in length. The longer length of microimplants permitted bicortical engagement of the palatal and nasal floor, reducing the force transmitted to the anchored teeth during expansion. The appliance activation varied with age and skeletal maturity of the patient. The expansion was terminated when 2–3 mm of overexpansion was achieved. CBCT scans were taken before treatment (T1) and immediately after expansion (T2). Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and angular dental tipping at the first molar region. A total expansion of 5.41 ± 2.18 mm was achieved, 59.23 ± 17.75% of which was attributed to skeletal expansion (3.15 ± 1.64 mm) with the first molars exhibiting buccal tipping of 2.56 ± 2.64°. The use of MARPE appliances such as MSE can be used to correct transverse maxillary deficiency in adolescent patients with minimal dentoalveolar side effects.

Skeletal, Dentoalveolar, and Periodontal Changes of Skeletally Matured Patients with Maxillary Deficiency Treated with Microimplant-assisted Rapid Palatal Expansion Appliances: A Pilot Study

Introduction Microimplant-assisted rapid palatal expansion (MARPE) has recently been offered to adult patients for correcting maxillary transverse deficiency. However, there is limited information in the literature on the success of this appliance and its skeletal and dental effects on skeletally matured patients. The purpose of this study was to investigate the immediate skeletal, dentoalveolar, and periodontal response to MARPE appliance using cone-beam computed tomography in a skeletally matured patient as assessed by the cervical vertebral maturation method. Materials and Methods Eight consecutively treated patients (2 females, 6 males; mean age of 21.9 ± 1.5 years) treated with a maxillary skeletal expander were included in the study. Measurements were taken before and after expansion to determine the amount of midpalatal suture opening, upper facial bony expansion, alveolar bone bending, dental tipping, and buccal bone thickness (BBT). Data were analyzed using a one-way ANOVA and matched-pair t-test (α = 0.05). Results Midpalatal suture separation was found in 100% of the patients with no dislodged microimplants. Total maxillary expansion was attributed to 41% skeletal, 12% alveolar bone bending, and 48% dental tipping. Pattern of midpalatal suture opening was found to be parallel in both the coronal and axial planes. On average, the absolute dental tipping ranged from 4.17° to 4.96° and the BBT was reduced by an average of 39% measured at the premolars and molars. Conclusions The MARPE appliance can be a clinically acceptable, nonsurgical treatment option for correcting mild to moderate maxillary transverse discrepancies for skeletally matured adult patients with a healthy periodontium.

Insertion torque values and success rates for paramedian insertion of orthodontic mini-implants : Aretrospective study.

Orthodontic mini-implants (OMIs) are areliable method to provide temporary orthodontic anchorage. We hypothesized that there is an optimal insertion torque (<10 Ncm) that can be used to ensure the success of self-drilling OMIs in the paramedian region. Included were 40 (26 females, 14 males) consecutive patients requiring palatal skeletal anchorage. Mean age was 17.3years (range 11.0-44.6 years) for female patients and 15.7 years (range 10.6-36.9 years) for male patients. A total of 22 patients received aBeneslider according to Wilmes for the distalization of maxillary first molars, 10patients received aMesialslider for the mesialization of maxillary first molars, and 8patients received abone-borne rapid palatal expansion (RPE) appliance. Torque values of 10-15 Ncm were recorded in 46.3% of the OMIs and 15-20 Ncm in 35% of OMIs. OMIs that endured the orthodontic force applied for ≥6months were considered assuccess. The overall success rate was 98.8%. No significant differences were found between insertion torque values with respect to the right and left sides, Jarabak's ratio, facial axis, and Frankfort to mandibular plane angle. There were no significant differences in the OMIs insertion torques with regard to the different appliances. No association was found between insertion torque and vertical skeletal morphology. With an overall success rate of 98.8%, the study hypothesis that greater insertion torque (>10 Ncm) will decrease the success rate and increase palatal OMI failure was rejected.

Changes in the midpalatal and pterygopalatine sutures induced by micro-implant-supported skeletal expander, analyzed with a novel 3D method based on CBCT imaging

BackgroundMini-implant-assisted rapid palatal expansion (MARPE) appliances have been developed with the aim to enhance the orthopedic effect induced by rapid maxillary expansion (RME). Maxillary Skeletal Expander (MSE) is a particular type of MARPE appliance characterized by the presence of four mini-implants positioned in the posterior part of the palate with bi-cortical engagement. The aim of the present study is to evaluate the MSE effects on the midpalatal and pterygopalatine sutures in late adolescents, using high-resolution CBCT. Specific aims are to define the magnitude and sagittal parallelism of midpalatal suture opening, to measure the extent of transverse asymmetry of split, and to illustrate the possibility of splitting the pterygopalatine suture.MethodsFifteen subjects (mean age of 17.2 years; range, 13.9–26.2 years) were treated with MSE. Pre- and post-treatment CBCT exams were taken and superimposed. A novel methodology based on three new reference planes was utilized to analyze the sutural changes. Parameters were compared from pre- to post-treatment and between genders non-parametrically using the Wilcoxon sign rank test. For the frequency of openings in the lower part of the pterygopalatine suture, the Fisher’s exact test was used.ResultsRegarding the magnitude of midpalatal suture opening, the split at anterior nasal spine (ANS) and at posterior nasal spine (PNS) was 4.8 and 4.3 mm, respectively. The amount of split at PNS was 90% of that at ANS, showing that the opening of the midpalatal suture was almost perfectly parallel antero-posteriorly. On average, one half of the anterior nasal spine (ANS) moved more than the contralateral one by 1.1 mm. Openings between the lateral and medial plates of the pterygoid process were detectable in 53% of the sutures (P < 0.05). No significant differences were found in the magnitude and frequency of suture opening between males and females. Correlation between age and suture opening was negligible (R2 range, 0.3–4.2%).ConclusionsMidpalatal suture was successfully split by MSE in late adolescents, and the opening was almost perfectly parallel in a sagittal direction. Regarding the extent of transverse asymmetry of the split, on average one half of ANS moved more than the contralateral one by 1.1 mm. Pterygopalatine suture was split in its lower region by MSE, as the pyramidal process was pulled out from the pterygoid process. Patient gender and age had a negligible influence on suture opening for the age group considered in the study.

Following Surgically Assisted Rapid Palatal Expansion, Do Tooth-Borne or Bone-Borne Appliances Provide More Skeletal Expansion and Dental Expansion?

The aim of this study was to compare outcome measurements of skeletal and dental expansion with bone-borne (BB) versus tooth-borne (TB) appliances after surgically assisted rapid palatal expansion (SARPE). This study was performed to provide quantitative measurements that will help the oral surgeon and orthodontist in selecting the appliance with, on average, the greatest amount of skeletal expansion and the least amount of dental expansion. A computerized database search was performed using PubMed, EBSCO, Cochrane, Scopus, Web of Science, and Google Scholar on publications in reputable oral surgery and orthodontic journals. A systematic review and meta-analysis was completed with the predictor variable of expansion appliance (TB vs BB) and outcome measurement of expansion (in millimeters). Of 487 articles retrieved from the 6 databases, 5 articles were included, 4 with cone-beam computed tomographic (CBCT) data and 1 with non-CBCT 3-dimensional cast data. There was a significant difference in skeletal expansion (standardized mean difference [SMD], 0.92; 95% confidence interval [CI], 0.54-1.30; P<.001) in favor of BB rather than TB appliances. However, there was no significant difference in dental expansion (SMD, 0.05; 95% CI, -0.24 to 0.34; P=.03). According to the literature, to achieve more effective skeletal expansion and minimize dental expansion after SARPE, a BB appliance should be favored.

A retrospective cephalometric study on pharyngeal airway space changes after rapid palatal expansion and Herbst appliance with or without skeletal anchorage.

BackgroundThe aim of this study is to investigate the pharyngeal airway space changes in patients treated with rapid palatal expansion (RPE) and Herbst appliance with or without skeletal anchorage.MethodsA 40-patient study group treated with the Herbst RME combination was included; moreover, a comparison between two subgroups based on whether miniscrews were used was evaluated. A subgroup 1 included 20 patients who were treated with RPE and an acrylic splint Herbst with miniscrews, and subgroup 2 included 20 patients who were treated with RPE and an acrylic splint Herbst. A cephalometric analysis was performed before (T1) and after (T2) treatment. The skeletal parameters of the sagittal occlusion analysis of Pancherz were utilized together with some extra measurements to evaluate the airways.ResultsAn increased nasopharyngeal airway space was observed in group 1 (p < 0.05) from T1 to T2. Furthermore, the increase in nasopharyngeal airway space was significantly higher in subgroup 1 (p < 0.05) in comparison to the subgroup 2. Oropharyngeal (OA) and laryngopharyngeal (LA) dimensions were significantly increased in the subgroup 1 at the end of the treatment. In the subgroup 1, a significant decrease in SNA, a significant increase in SNB, and a significant decrease in ANB were observed from T1 to T2. In the subgroup 2, the treatment resulted in a significant decrease in ANB. In both groups, Pogonion increased significantly from T1 to T2.ConclusionsThe results suggest that the RPE and the Herbst appliance allow a slight improvement of the sagittal dimensions of the airways. The oropharyngeal dimension increased significantly more in the skeletal anchorage group.

Microimplant-assisted rapid palatal expansion appliance to orthopedically correct transverse maxillary deficiency in an adult

This case report describes the use of a microimplant-assisted rapid palatal expansion (MARPE) appliance to orthopedically correct a transverse maxillary deficiency in an adult patient. Expansion forces transmitted through the teeth in traditional rapid palatal expansion appliances create unwanted dental effects rather than true skeletal expansion, particularly in older patients with more rigid interdigitation of the midpalatal suture. This 19-year-old patient had maxillary constriction with a unilateral posterior crossbite. A MARPE appliance secured to the palatal bones with 4 microimplants was expanded by 10mm. Pre-MARPE and post-MARPE cone-beam computed tomography cross sections demonstrated 4 to 6mm of expansion of the maxillofacial structures, including the zygoma and nasal bone area, and widening of the circummaxillary sutures. Minor buccal tipping of the dentition was observed, but the integrity of the alveolar bone was preserved. This report demonstrates that careful design and application of the MARPE appliance can achieve successful transverse expansion of the maxilla and the surrounding structures in a patient beyond the age typically considered acceptable for traditional rapid palatal expansion.

Survival of palatal miniscrews used for orthodontic appliance anchorage: A retrospective cohort study

The purpose of this study was to examine the overall success of miniscrews inserted in the paramedian palatal region for support of various appliances during orthodontic treatment. The patients received 1 or 2 miniscrews in the paramedian anterior palate of 8.0-mm length and 1.6-mm diameter placed during orthodontic treatment by the same experienced orthodontist. In total, 196 patients (121 girls, 75 boys; median age, 11.7; interquartile range, 3.7) who received 384 miniscrews were evaluated. Two hundred four miniscrews were used with rapid palatal expansion appliances, 136 with appliances for distalization of posterior teeth, and 44 with other appliances, such as transpalatal arches for tooth stabilization. The overall survival of the miniscrews was excellent (97.9%) in the cases examined. Cox regression analysis showed no difference in the overall survival rates of miniscrews loaded with different appliances for sex (hazard ratio, 0.95; 95% confidence interval, 0.71-1.27; P = 0.73) after adjusting for appliance and age. This study shows that miniscrews placed in the paramedian anterior palate for supporting various orthodontic appliances have excellent survival.

To beam or not to beam: that is the question: Author response

In response to the letter by Aps1 concerning our papers published in DMFR2 and the September 2012 issue of the European Journal of Paediatric Dentistry (EJPD),3 we would like to provide clarification and evidence of the careful approach taken to the orthodontic and radiological procedures employed in these studies. Importantly, we would like to clarify that the authors do not use ionizing radiation as a daily orthodontic diagnostic tool. Careful dosage and ionizing radiation should be used only in specific clinical conditions such as impacted canines, supernumerary teeth and temporomandibular joint arthritis, and in planning orthognathic surgery.4 As was reported clearly in the article and could be seen easily in the figures, all patients in the study sample presented with severely displaced maxillary canines. Canine impaction is one of the clinical conditions in orthodontics for which evidence-based research for the clinical application of three-dimensional (3D) imaging exists. Thus, the primary indication for the low-dose CT was to evaluate the position of displaced intraosseus canines in the maxilla. These data cannot be detected using dental casts. While it is true that the position of the crown determines the surgical approach and direction of traction, the direction of eruption and location of the root apex play important roles in the orthodontic mechanics, avoiding damage to adjacent teeth and improving the effectiveness of canine traction.5 Hofmann et al6 developed a system on 3D imaging that allows for accurate evaluation of the position of the displaced canines relative to three spatial planes. The Department of Orthodontics at the University of Rome “Tor Vergata” is specialized in the treatment of impacted canines often associated with other dental anomalies such as supernumerary teeth and missing or peg-shaped lateral incisors.7,8 Consequently, we applied the protocol reported in several papers9–12 demonstrating that rapid maxillary expansion (RME) is an orthopaedic procedure that improves the initial intraosseus position of the canines and increases the rate of eruption of palatally displaced maxillary canines compared with an untreated control group. The present study sample is a very unique sample in the literature, and it allowed for scientific investigation of the skeletal, dental and periodontal effects of RME, one of the procedures most commonly applied and most debated in orthodontics. All of these effects (which cannot be derived using dental casts only) were analysed using the same sample in different publications by our research group.2,13–16 The imaging protocol in the present study was carefully planned with our radiologist to minimize patient dosage in low-resolution and small field of view (FOV) image acquisitions. The trained radiology technician reduced the voltage to the lowest possible level (80 kV) and restricted the area investigated strictly to the maxilla, adapting the FOV from a minimum of 6 cm to a maximum of 13 cm. Despite this, the accuracy of the measurements performed was not compromized. With this careful imaging protocol, the radiation dosage of three low-dose CT scans, considering their stochastic effect, is much smaller and not comparable to one multislice skull CT. The two images published in the EJPD demonstrate, contrary to what is claimed by Professor Aps, the high level of standardization involved where imaging acquisition was carried out by a single radiographer at the same scanner console, and the careful positioning of the patients' heads. Head position was standardized using perpendicular light beams, and the axial CT images were reconstructed always as parallel to the palatal plane and passing through the trifurcation of the right upper first molar, with the same method reported in numerous previous articles.17–28 For this reason, it was not necessary to add a figure; in addition, with the device in situ, it was possible to draw clearly the circle area because the expander was located in a more occlusal position at crown level, while the axial images were at the root level of anchored tooth. We thank Professor Aps for sharing the link to Image Gently, which is an initiative we certainly applaud. We absolutely agree that imaging as gently as possible, keeping the patient benefits and risks in mind, is our most sincere goal. In summary, as paediatric dentists, we are guarding over the health of our young patients, and as orthodontists, it is our duty to plan a treatment as conservative as possible, especially in clinical cases that need a combined surgical–orthodontic approach. Thus, all subjects of the study sample benefited from this research protocol and achieved successful treatment outcomes thanks to adequate treatment planning based on careful use of the right diagnostic tools.

Nonsurgical orthodontic treatment for an adult with skeletal open bite, class III malocclusion and posterior crossbite: A case report

Class III malocclusion associated with skeletal anterior open bite pattern in adults can be a challenging orthodontic problem, especially for the nonsurgical treatment. Conventionally, several treatment alternatives are available such as tooth extraction, molar intrusion, and absolute anchorage system or orthognathic surgical correction. Although correction with surgery may be the most effective and stable way, many patients refused surgical treatment plan because of the costs and traumas it may bring. We reported a nonsurgical orthopedic treatment of 22-year-old male with severe skeletal anterior open bite, dental Class III malocclusion, posterior crossbite and a high mandibular plane angle. The patient refused surgery and extraction. So we formulated a treatment plan consisting of using rapid palatal expansion appliance to expand the maxilla, standard edgewise brackets to align the teeth, Class III elastics to correct the canines, premolars, and molars relationship, reverse curve of the nickel-titanium wire combined with anterior vertical elastics to intrude molars and correct open bite. In this case, without suffering of surgery, the posterior crossbite was ideally corrected, and ideal overjet and overbite relationships and functional occlusion were all achieved. The patient obtained satisfactory occlusal as well as functional and stable results.

Measurement of somatosensory-evoked potential to evaluate function of the trigeminal nerve after rapid palatal expansion treatment in a rabbit model

The aim of this study was to evaluate whether high force or stress response occurs in rapid palatal expansion (RPE) on the skull base would affect the function of trigeminal nerve and its branches by measuring trigeminal somatosensory-evoked potential (TSEP). Twenty-four male New Zealand white rabbits were selected when they were 12-13 weeks old with mean weight around 3.05 ± 0.33 kg. A modified acrylic-bonded RPE appliance was used as an expansion tool. Through a series of TSEP measurements performed before the expansion treatment (T0), on the third day of the expansion (T1), at the end of the expansion process (T2), and after 10 days of retention (T3), function of the trigeminal nerve was analyzed with statistical models, including the Kruskal-Wallis test and paired t tests. A stable short-latency response represented by a "W" waveform was consistently identified on the TSEP spectram analysis. Within-subject comparisons between the experimental group and control group did not show significant differences on TSEP of maxillary nerve and of mandibular nerve. TSEP is a valuable technique for a comprehensive evaluation of the trigeminal system. Our study demonstrates that rapid palatal expansion is a safe orthopedic method regarding function of the trigeminal nerve during expansion and short-term retention period in young rabbits.

Long-term maxillary changes in patients with skeletal Class II malocclusion treated with slow and rapid palatal expansion

In this study, we evaluated the long-term maxillary changes in skeletal Class II patients who had slow and rapid palatal expansion. The sample consisted of 70 patients divided in 2 groups: 1 group was treated with cervical headgear with expanded inner bow (CHG) and the other with a Haas-type rapid palatal expansion appliance with cervical headgear (RPE-CHG). Data were collected in the molar and canine regions for basal width, alveolar width, and palatal depth at pretreatment (T1), posttreatment (T2), and postretention (T3). The Student paired t test was used to compare data and independent averages between phases. In both groups, from T1 to T2, there were significant increases in basal width, alveolar width, and palatal depth for the molar region; in the canine region, there was a significant increase only in the alveolar width. From T2 to T3, no significant changes were found for basal and alveolar widths in both groups and regions, but a significant increase was seen in palatal depth in the molar region in the RPE-CHG group. Slow and rapid palatal expansion can expand the maxillae and the maxillary teeth in skeletal Class II patients. Rapid palatal expansion was efficient in the treatment of skeletal Class II patients with severe transverse maxillary discrepancy. Skeletal Class II correction with slow and rapid palatal expansion produced long-term stability (10 years after orthodontic treatment).

Nonsurgical orthodontic treatment of an adolescent girl with Class III malocclusion and asymmetric maxillary narrowing

Class III malocclusion is a difficult anomaly to understand. Because not all Class III patients are candidates for surgical correction, patient assessment and selection are especially important in diagnosis and treatment planning. In this article, we report the orthopedic treatment of a teenage girl with a severe skeletal Class III malocclusion. Her ANB angle was -4.5 degrees, and she had a 2-mm anterior crossbite, a 1-mm overbite, and a posterior asymmetric crossbite (greater on the left side). The patient refused surgery. We used a rapid palatal expansion appliance to expand the maxilla, standard edgewise brackets to align the teeth, and reverse headgear to bring the maxilla forward. We performed symmetric expansion, but, because of the asymmetric crossbite in the maxilla, we designed a modified apparatus that permitted greater relapse on 1 side. In this way, the posterior crossbite was ideally corrected by the end of treatment, and ideal overjet and overbite relationships, functional occlusion, and an esthetic facial appearance were all achieved.

Use of conventional tomography to evaluate changes in the nasal cavity with rapid palatal expansion

The relationship between nasal airway resistance and the use of rapid palatal expansion appliances remains controversial. The purpose of this study was to use conventional tomography to determine the anatomical changes in the nasal cavity after maxillary expansion. Nineteen patients (aged 8-15 years) were included in the study. Tomograms were taken before expansion (T1), immediately after expansion (T2), and 3 months after expansion (T3). Areas for the left and right anterior, middle, and posterior nasal cavity and total volume were calculated by using the computer software, AutoCAD LT 2005. Data were analyzed with paired t tests. Significant increases in area were found in the anterior nasal cavity from T1 to T2 (0.85 +/- 1.19 cm2, 11.7% increase), T2 to T3 (1.18 +/- 1.2 cm2, 22.2% increase), and T1 to T3 (2.6 +/- 1.7 cm2, 35.7% increase) (P <.05). Similar increases were found in the middle and posterior nasal cavity. Significant increases in volume were found from T1 to T2 (2.1 +/- 2.7 cm3, 10.7% increase), T2 to T3 (4.9 +/- 2.3 cm3, 22.6% increase), and T1 to T3 (6.99 +/- 2.45 cm3, 27.8% increase). No significant differences were found in the area or the volume of the left and right sides of the nasal cavity. Individual variations in response to maxillary expansion were large for most of the parameters tested. These data suggest that rapid palatal expansion is usually accompanied by increases in area and volume of the nasal cavity, and these changes remain stable 3 months after maxillary expansion.

Comparison of Protraction Facemask Response Using Banded and Bonded Expansion Appliances as Anchorage

Protraction headgear has been used in combination with various fixed appliances as anchorage to correct Class III malocclusions with maxillary deficiency. The objective of this study was to compare the treatment response of maxillary protraction in combination with either the banded or the bonded rapid palatal expansion appliance. The sample consisted of pre- and posttreatment cephalometric radiographs of 20 patients treated with the banded expansion appliance, 20 patients treated with the bonded expansion appliance, and 20 control patients with no treatment who were matched in sex, age, and skeletal morphology. The average treatment time for the bonded group was 10 ± 2.1 months and the banded group was 9.5 ± 1.9 months. Traditional cephalometric measurements as well as the Pancherz analysis were used to describe the dental and skeletal changes in response to treatment. Data were analyzed using the analysis of variance (ANOVA) and paired <i>t</i> test. There were no significant differences in the forward movement of the maxilla between the banded and bonded expansion groups. The forward movement of the maxilla was 1.0 mm and 1.7 mm greater than in the control group, respectively. The full coverage of the occlusal surface by acrylic did not increase the efficiency of forward maxillary movement. Loss of anchorage was found in both treatment groups. The skeletal and dental contributions to the correction of overjet and overbite were quite similar in the two treatment groups. Maxillary expansion and protraction was accompanied by vertical displacement of the maxilla, increase in lower face height, and vertical eruption of posterior molars, irrespective of the type of anchorage appliance.

Multitomographic evaluation of the dental effects of two different rapid palatal expansion appliances

Rapid palatal expansion (RPE) is widely used in the treatment of transverse maxillary deficiencies. Generally, there are two types of RPE appliances: banded and bonded expanders. The purpose of this prospective study was to compare the dental effects of banded and bonded appliances. The study consisted of 23 patients (13 females and 10 males) with a bilateral maxillary deficiency. Twelve patients (seven females and five males) with a mean age of 14.8 +/- 0.3 years were treated with banded RPE and 11 patients (six females and five males) with a mean age of 15.1 +/- 0.7 years with bonded RPE. Multitomographic radiographs were taken before (T0) and at the end (T1) of expansion while the patients were wearing an acrylic mandibular appliance in which ball bearings and bars were embedded. Statistical analyses of the measurements at T0 and T1 were undertaken with a paired t-test, and the difference between the groups assesed with a Student's t-test. In both groups, the angle between the radiographic image of the bar and the axial inclination of the upper first premolar and molar teeth was (5.34 and 2.73 degrees for the right premolars, 5.17 and 2.28 degrees for the left premolars, 11.83 and 3.73 degrees for the right molars, and 9.75 and 5.64 degrees for the left molars in the banded and bonded groups, respectively. The distance from the vestibular cortical plate to the palatal root of these teeth (1.17 and 1.23 mm for the right premolars, 2.46 and 1.09 mm for the left premolars, 2.75 and 0.64 mm for the right molars, 2.23 and 0.96 mm for the left molars in the banded and bonded groups, respectively) increased (both P < 0.01). These increases indicated buccal tipping of the teeth. Comparison of the two groups showed that tipping of the first molar and premolar teeth in the banded group was significantly more than in the bonded group (P < 0.01 and P < 0.001, respectively).

Treatment of a unilateral Class II crossbite malocclusion with traumatic loss of a maxillary central incisor and a lateral incisor

This case report describes the multidisciplinary management of an adolescent girl with traumatic loss of the maxillary right central lateral incisors, and a unilateral Class II crossbite malocclusion. A rapid palatal expansion appliance was used initially to correct the transverse deficiency and secondarily as an anchorage unit for unilateral molar distalization to correct the Class II molar relationship. Temporary incisors were extended from a Nance stabilizing appliance during premolar and canine retraction. A staged approach was used with bone grafting before the placement of 2 single-tooth implants. A favorable outcome was achieved through proper coordination among the orthodontist, the surgeon, and the restorative dentist.

Skeletal and dental response to rapid maxillary expansion with 2- versus 4-band appliances

Banding a rapid palatal expansion (RPE) appliance to the 2 first molars has been proposed as an equivalent to the conventional 4-band RPE appliance. However, the dentoskeletal response to this treatment has not been evaluated. Twenty-eight subjects (aged 8-20 years) who required maxillary expansion were matched by age and randomly assigned to either a 2-band or a 4-band RPE group. Skeletal and dental responses were measured from standardized anteroposterior cephalometric and occlusal radiographs and dental casts before treatment (T1), at the end of expansion (T2), and at 1 year postexpansion (T3). At T2, suture expansion was 2.5 times greater and arch perimeter was 6-fold larger in the 4-band than in the 2-band group. Both appliances displayed the typical "V" expansion of the suture and "reverse V" expansion of the dental arch. At T3, remineralization reduced the suture opening by 75%, but 95% to 99% of the dental reaction was maintained. The 2-band group demonstrated a significant inverse age-dependent correlation ( r = -0.795), with treatment failure beyond 12 years of age, whereas the 4-band group was age-independent. The greater the skeletal resistance, the smaller the sutural response but the greater the dental response to RPE therapy. Four-band RPE is indicated when severe anterior crowding is accompanied by a tapered arch form, and 2-band RPE is recommended in the mixed dentition when mild crowding occurs with posterior constriction.

Frequency of and Complications in the Use of RPE Appliances?Results of a Survey in the Federal State of Hesse, Germany

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). 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. 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. 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.

Nickel Allergy Associated with a Transpalatal Arch Appliance

The purpose of this article was to present a case in which nickel sensitivity of the oral mucosa was demonstrated during the use of a transpalatal arch appliance (TPA). An 11-year 8-month old post-menarchal female presented for orthodontic treatment with Class III buccal segments and bilateral open bite. The treatment plan consisted of placing a rapid palatal expansion appliance (RPE) and a TPA with soldered lateral tongue cribs, in order to eliminate her tongue thrusting habit. 8 months into treatment, the gingiva of the right posterior segment began to hypertrophy, particularly around the bands of the right first molar and premolar. A patch test of 5% nickel sulfate indicated a positive reaction to nickel. The treatment was finished without the use of nickel titanium wires and the mucosa reaction resolved. The patient had had her ear pierced at age 2 days old, which was 11 years before orthodontic treatment was initiated. The literature shows that this exposure may have been the sensitizing event. While the nickel sensitive patient may not present an extreme medical risk, the orthodontist must be aware of the problem and the likelihood of treating patients with this condition. It appears that the reaction may vary from patient to patient. The practitioner should possess a basic understanding of the occurrence rate, sex predilection, and signs and symptoms of allergy to nickel, and should be familiar with the best possible alternative modes of treatment, to provide the safest, most effective care possible in these cases. Practitioners should be aware that symptoms of nickel allergy may closely mimic those of typical gingival changes during orthodontic treatment of circumpubertal children.