Bilateral Posterior Crossbite Research Articles

Muscular and condylar response to rapid maxillary expansion. Part 1: Electromyographic study of anterior temporal and superficial masseter muscles

In this prospective clinical study, we investigated the effects of rapid maxillary expansion (RME) on the electromyographic (EMG) activities of the anterior temporal and superficial masseter muscles. The sample included 18 subjects (11 girls, 7 boys; mean age, 12.54 years) with unilateral or bilateral posterior crossbites involving 3 or more posterior teeth. There was no control group in this study because of the short observation period. The EMG activity was recorded simultaneously from both muscles during swallowing a sip of water and unilateral gum chewing. The mean EMG (mEMG) activities of the right and left anterior temporal muscles showed no statistically significant difference during swallowing and unilateral chewing. The mEMG activities of the right and left masseter muscles showed a statistically significant difference at unilateral chewing (P <0.01). There were a decrease of the mEMG activities for both muscles after RME and an increase during the observation period for unilateral chewing (P <0.05). Swallow-related mEMG activities of both muscles showed increases after RME and during the observation period (P <0.05). RME affected the EMG activities of the anterior temporal and superficial masseter muscles during swallowing and unilateral chewing. These findings suggest that the alterations in the EMG activities of these muscles should be considered in both the treatment and the the stability of maxillary transverse deficiencies.

Treatment of mutilated malocclusion – A case report

A case report of 19-year old man who had an skeletal Class III mutilated malocclusion characterized by bilateral posterior cross bite & open blte, crowding, nail-biting, mouth breathing habit etc. A non-surgical approach was used to obtain significant improvement in occlusion & facial esthetics.

Dental arch symmetry in unilateral and bilateral posterior crossbite in Egyptian children

Dental arch symmetry in unilateral and bilateral posterior crossbite in Egyptian children

Epidemiology of Posterior Crossbite in the Primary Dentition

This epidemiological survey was conducted on 2,016 children from 8 private and 12 public preschools at the city of Bauru, São Paulo, Brazil. The sample was composed of 1,032 males and 984 females in the primary dentition stage, aged 3 to 6 years. Normal occlusion was observed in 26.74% of the sample; thus, 73.26% of children presented some type of malocclusion. Among the malocclusions, the following transverse problems were diagnosed: unilateral posterior crossbite (11.65%), anterior open bite associated with posterior crossbite (6.99%), bilateral posterior crossbite (1.19%), unilateral posterior crossbite associate with anterior crossbite (0.79%) and full crossbite (0.19%) totalizing 20.81% of the transverse problems. Mandibular functional deviation was observed in 91.91% of children with unilateral posterior crossbite, characterizing the functional unilateral posterior crossbite. The results demonstrated that the prevalence of posterior crossbite was compatible with previous data in the literature, with predominance of functional unilateral posterior crossbite.

Condylar Asymmetry in Bilateral Posterior Crossbite Patients

To investigate whether patients with bilateral posterior crossbite have asymmetrically developed condyles. The study group consisted of 75 patients with bilateral posterior crossbite, and a control group of 75 subjects with normal occlusion. Condylar, ramal, and condylar plus ramal asymmetry values were computed for all of the subjects on orthopantomograms. Data were analyzed statistically by means of paired t-test and Student's t-test. The patients with bilateral posterior crossbite had more asymmetrical condyles relative to the controls. However, there were no statistically significant differences in condylar, ramal, or condylar plus ramal heights between left and right sides in both the control and crossbite groups. Patients with bilateral posterior crossbite can have asymmetrical condyles and might be at risk for the development of future skeletal mandibular asymmetries.

Nonsurgical rapid maxillary expansion effects on craniofacial structures in young adult females. A bone scintigraphy study.

To evaluate the skeletal effects of nonsurgical rapid maxillary expansion (RME) on craniofacial structures with bone scintigraphy in young adult female subjects. The material of the present study consists of scintigraphic records taken from 17 early adult females treated with RME. All patients had a bilateral posterior crossbite, transverse maxillary deficiency, deep palatal vault, and dental crowding at the beginning of the treatment. The age range of the patients was 16.1 to 18.8 years, and the mean age was 17.3 +/- 0.86 years. Bone scintigraphy records were obtained before RME (T1), during the splitting of the midpalatal suture (T2), and after the end of active widening period (T3). Repeated measure analysis of variance was used to assess the differences between the periods. In addition, Bonferroni multiple comparison tests were applied to the measurements at which F values were found to be statistically significant. According to the statistical analysis, significant activity changes were found in all regions studied and in all slices. The metabolic activity in all regions showed significant increases up to the separation of the midpalatal suture (T1-T2), whereas the metabolic activity exhibited a remarkable decrease (T2-T3) after the opening of the midpalatal suture. Scintigraphic records revealed an increase in the regions of interest scores during RME in all regions and all slices. Therefore, it can be speculated that RME has had not only dental effects but also skeletal effects on young adult patients.

Periodontal effects of rapid maxillary expansion with tooth-tissue-borne and tooth-borne expanders: A computed tomography evaluation

The force delivered during rapid maxillary expansion (RME) produces areas of compression on the periodontal ligament of the supporting teeth. The resulting alveolar bone resorption can lead to unwanted tooth movement in the same direction. The purpose of this study was to evaluate periodontal changes by means of computed tomography after RME with tooth-tissue-borne and tooth-borne expanders. The sample comprised 8 girls, 11 to 14 years old, with Class I or II malocclusions with unilateral or bilateral posterior crossbites Four girls were treated with tooth-tissue-borne Haas-type expanders, and 4 were treated with tooth-borne Hyrax expanders. The appliances were activated up to the full 7-mm capacity of the expansion screw. Spiral CT scans were taken before expansion and after the 3-month retention period when the expander was removed. One-millimeter thick axial sections were exposed parallel to the palatal plane, comprising the dentoalveolar area and the base of the maxilla up to the inferior third of the nasal cavity. Multiplanar reconstruction was used to measure buccal and lingual bone plate thickness and buccal alveolar bone crest level by means of the computerized method. RME reduced the buccal bone plate thickness of supporting teeth 0.6 to 0.9 mm and increased the lingual bone plate thickness 0.8 to 1.3 mm. The increase in lingual bone plate thickness of the maxillary posterior teeth was greater in the tooth-borne expansion group than in the tooth-tissue-borne group. RME induced bone dehiscences on the anchorage teeth's buccal aspect (7.1 +/- 4.6 mm at the first premolars and 3.8 +/- 4.4 mm at the mesiobuccal area of the first molars), especially in subjects with thinner buccal bone plates. The tooth-borne expander produced greater reduction of first premolar buccal alveolar bone crest level than did the tooth-tissue-borne expander.

Evaluation of condylar position from transcranial projections in primary dentition

To evaluate the condylar position through transcranial radiographs in children between 3 years and 6 years old and to associate it with morphological characteristics of primary dentition. The extraoral transcranial radiographs were taken with plain films using the Accurad-200 head holder (Denar Company, Anaheim, CA), and then they were digitized using a Hewlett Packard 6390 Scanner. The condylar position was determined according to Gelb's template, in postural rest position (RP) and maximum intercuspal position (MI), and it was associated with the characteristics: normal occlusion (n=36), open bite with or without overjet greater than 3 mm (n=27), unilateral or bilateral posterior cross bite (n=14), overbite greater than 3 mm (n=15). The chi-square and the Fisher Exact Test were used to analyse the data. It was verified that when using Gelb's template, there was not a significant association between the occlusion type found and the position of the condyle in the glenoid fossa when considering the entire patient sample (P>0.05). There was a great variability in positions, and most of the children had asymmetric condyles (55.43% in MI and 51.09% in RP). Children with normal occlusion and malocclusion presented the same proportions of condylar position in both mandibular positions. In conclusion, the results of this study showed that the condylar position in small children with different morphological occlusions presented great variability.

Effect of rapid maxillary expansion on the dimension of the nasal cavity and on nasal air resistance

Atresia of the maxilla is a transverse skeletal dysplasia, possibly associated with respiratory problems. For its correction, rapid maxillary expansion is a feasible orthodontic process. To evaluate the effect of rapid maxillary expansion on the nasal cavity by acoustic rhinometry and computed rhinomanometry. Twenty-nine children of both sexes with oral and/or mixed breathing, ranging in age from 7 to 10 years and with mixed dentition were selected. The children had uni- or bilateral posterior crossbite involving deciduous canines and the first permanent molars and were not being submitted to any otorhinolaryngologic or orthodontic treatment. All subjects were submitted to rhinologic exams and orthodontic documentation at three different times, i.e., before expansion and immediately and 90 days after expansion. There was no difference in the minimal cross-sectional area at the level of the valve and inferior nasal turbinate between the periods analyzed, but there was a statistically significant reduction in nasal resistance after expansion. On the basis of the present results, we may conclude that rapid maxillary expansion may lessen the nasal resistance. Although there was no difference in nasal geometry. Thus, this procedure may improve nasal respiration, but cannot be indicated for this purpose by itself.

Extreme dentoalveolar compensation in the treatment of Class III malocclusion

The orthodontic treatment of an adult patient with a skeletal Class III malocclusion, increased anterior facial height, negative overjet, and bilateral posterior crossbite is presented. Treatment options included mandibular first premolar or third molar extractions with dentoalveolar compensation or combined surgical-orthodontic treatment. Mandibular third molar extraction with dentoalveolar compensation was the treatment choice. Biofunctional brackets, with accentuated lingual crown torque on the maxillary incisors and accentuated buccal crown torque on the mandibular incisors, were used. The anterior crossbite was corrected with intermaxillary elastics from the palatal aspect of the maxillary incisors to the labial aspect of the mandibular incisors. Class III elastics moved the maxillary teeth mesially and assisted in retruding the mandibular teeth. Patient compliance with the elastics was excellent, and satisfactory dentofacial esthetics were achieved. This treatment protocol has rigorous indications, and it is not a routine plan. The mechanotherapy and the pros and cons of this approach are discussed.

Orthodontic treatment of dental arch transverse disharmony in complete unilateral cleft lip and palate patients

To investigate the dental arch discrepancy in UCLP patients and the characteristics of orthodontic treatment of this kind of patients. 48 Unilateral cleft lip and palate patients were examined clinically and dental arch transverse discrepancy were recorded. Treatment plan was made according to the maloccusion of each patient. (1). Dental arch transverse discrepancy was seen in 60.4%, bilateral posterior crossbite in 33.3%, and unilateral posterior crossbite in 16.7% of patients with UCLP, respectively. (2). Serious crossbite was often seen in bicuspid region, so expansion in this area is the main task of orthodontic treatment. (3). Dental arch transverse discrepancy was usually mild in molar region. The upper molars were moved palatally in 10.4% of patients with UCLP. Upper arch expansion is often needed in patients with UCLP, and the potential of dental arch expansion was large. The decision of upper tooth extraction in patients with moderate crowding should be made after dental arch expansion. Dental arch expansion should be done before alveolar bone grafting. Prolonged usage of the retainer is often needed.

The effects of nitanium maxillary expander appliances on dentofacial structures.

The aim of this study was to determine the sagittal, transverse, and vertical effects of a Nitanium maxillary expansion appliance on dentofacial structures in patients with bilateral posterior cross bites in the permanent dentition. For this purpose, and without distinguishing the skeletal classification, a total of 16 patients (4 boys and 12 girls) with a mean age of 13.8 years and a bilateral posterior crossbite in the permanent dentition were chosen. Lateral and frontal cephalometric radiographs, maxillary and mandibular plaster models and periapical radiographs were obtained from each patient at pretreatment (T1), post-treatment (T2), and at the end of the retention period (T3) time points. The measurements that were obtained from the lateral and frontal cephalometric radiographs and maxillary and mandibular plaster models were evaluated by a Wilcoxon paired 2-sample test. This test compares 3 pairs of time points, the pretreatment (T1) and posttreatment (T2), the pretreatment (T1) and post retention (T3), and the post-treatment (T2) and post retention (T3). Periapical radiographs were used to demonstrate changes in the midpalatal suture. Skeletal expansion occurred simultaneously with dentoalveolar expansion in the transverse plane with the Nitanium maxillary expansion appliance. The upper incisors were extruded and retroclined. Also, the extrusion of the upper first molars caused the mandible to rotate backward and downward. This resulted in an increased vertical dimension of the lower face. It was clinically observed that the posterior cross-bite and mesiopalatal rotation of the upper first molars were improved and that the crowns of these teeth were moved slightly to the distal side.

Photographic analysis of facial changes associated with maxillary expansion

Previous studies on the effects of surgical and rapid palatal expansion have been largely based on general skeletal and dental findings ascertained from radiographs and casts. The aim of this study was to measure and compare the soft tissue changes of the face during the expansion process and to determine the stability of any changes 1 year later. The sample consisted of 44 patients with unilateral or bilateral posterior crossbites. Twenty-four of the patients required a surgically assisted expansion procedure, and a second group of 20 patients were treated with orthopedic expansion. Ten measurements were made from standardized frontal facial photographic slides at 5 intervals of treatment: initial, bond appliance, stop expansion, debond appliance, and 1 year retention. Differences over time between the surgical and nonsurgical groups were analyzed by a 2 way multivariate analysis of variance (MANOVA) and post hoc t tests. Differences between initial and 1 year retention were found in the nasal widths ( P < .001) of both surgical and nonsurgical groups. Other significant changes and trends were discussed. (Am J Orthod Dentofacial Orthop 1999;116:563-71)

Oral Health Status of Russian Children with Unilateral Cleft Lip and Palate

Abstract Objective: To evaluate the oral and dental health of Russian children who underwent Frolova primary palatoplasty. Design: Eighty-nine children (62 boys and 27 girls; age range, 5 to 9 years) who had undergone repair of unilateral cleft lip and palate were included in this oral/dental evaluation. Factors such as stage of dentition; oral hygiene; carious, missing and restored teeth; and occlusion were recorded. Results: Twenty-six of the 89 patients presented with a palatal fistula. Oral hygiene of patients without a palatal fistula was significantly better than that of patients with a fistula (p < .01). Forty-five percent of patients had eight or more decayed teeth. Significantly more patients with palatal fistulae had class II soft tissue facial profiles than those without palatal fistulae. Anterior crossbites were found in 48% of patients, unilateral posterior crossbites in 58%, and bilateral posterior crossbites in 12%. Conclusions: The high percentage of poor oral hygiene and dental caries fou...

Oral health status of Russian children with unilateral cleft lip and palate.

To evaluate the oral and dental health of Russian children who underwent Frolova primary palatoplasty. Eighty-nine children (62 boys and 27 girls; age range, 5 to 9 years) who had undergone repair of unilateral cleft lip and palate were included in this oral/dental evaluation. Factors such as stage of dentition; oral hygiene; carious, missing and restored teeth; and occlusion were recorded. Twenty-six of the 89 patients presented with a palatal fistula. Oral hygiene of patients without a palatal fistula was significantly better than that of patients with a fistula (p < .01). Forty-five percent of patients had eight or more decayed teeth. Significantly more patients with palatal fistulae had class II soft tissue facial profiles than those without palatal fistulae. Anterior crossbites were found in 48% of patients, unilateral posterior crossbites in 58%, and bilateral posterior crossbites in 12%. The high percentage of poor oral hygiene and dental caries found in this group of patients is likely due to the general unavailability of dental hygiene products and the high cost of these products when available. In addition, it seems there is limited understanding by parents of the importance of dental hygiene and appropriate diet in preventing dental disease.

COMPARISON of DENTOFACIAL CHANGES with RIGID ACRYLIC BONDED and HAAS TYPE BANDED RAPID MAXILLARY EXPANSION DEVICES

SUMMARY: The aim of this study was to describe and compare the dentofacial changes obtained with the Haas type banded and rigid acrylic bonded RME therapies. Lateral and posteroanterior radiographs, and dental casts of 30 growing children who had unilateral or bilateral posterior crossbite were analysed. The study groups consisted of 21 cases treated with acrylic bonded and 9 cases treated with Haas type banded RME appliances. Results revealed that lower nasal width, basal maxillary width and intermolar width were increased in both groups. Increase in the inclination of the upper molars in the transversal direction was more in the banded group compared to the bonded group (p < 0.05) Overbite was markedly reduced in the banded group (-2.51 mm), while slightly decreased in the bonded group (-0.61 mm), and the difference between the two groups was statistically significant (p < 0.01). The findings of this study suggest that the rigid acrylic bonded RME appliance may be an acceptable alternative compared to t...

Skeletal and dental changes after maxillary expansion in the mixed dentition

The purpose of this study was to compare skeletal and dental aspects of three different expansion methods in the mixed dentition period in sagittal, vertical, and transversal planes, treatment periods, complications, and relapse tendencies in early periods. Patients with unilateral or bilateral posterior crossbites in the mixed dentition were studied. They were divided into three groups of 10 patients in each group. The first group received treatment with removable plates for semirapid maxillary expansion; the second group with quad-helix appliances for slow maxillary expansion; and the third group with conventional fixed hyrax appliances for rapid maxillary expansion (RME). Lateral and posteroanterior cephalometric films, occlusal films, and dental casts were taken before and after expansion, and after retention with the same appliances. Cephalometric and dental cast analyses were made. Both skeletal and dental changes were observed after all three expansion methods.

An American Board of Orthodontics case report

A case report of a malocclusion with bilateral congenital absence of the maxillary lateral incisors; unilateral absence of a mandibular lateral incisor; and a bilateral posterior cross-bite with a functional shift on closure, treated to the standards of the American Board of Orthodontics.

Occlusal disharmonies in mongolism (Down's syndrome)

Class I. Twenty-three (46 per cent) Class I relationships with the following irregularities: Right lingual unilateral posterior cross-bites; bilateral lingual posterior cross-bites; anterior open-bites; anterior cross-bites of lateral incisors and end-to-end occlusion; anterior cross-bite; overjet; anterior flaring; maxillary anterior crowding; bimaxillary protrusion. Class ZZ. Sixteen (32 per cent) Class II relationships, twelve Class II, Division 1, and four Class II, Division 2. CZass ZZZ. Eleven (22 per cent) Class III relationships. The most striking feature in evaluating the occlusal relationships in this group was the high incidence of Class III relationships and the prevalence of lingual unilateral and bilateral posterior cross-bites. In a high percentage of the cases studied, a contributing factor to the Class III relationships and the posterior cross-bites was a generalized reduction in palatal width and length. The tongue played a minor role in the Class III relationships, since there were only a small number of cases (two) that manifested a true macroglossia. Occlusal disharmonies are pathognomonic of Down’s syndrome in the present study, since in no single instance was there a harmonious occlusal relationship.

A Modern Concept of Orthodontic Diagnosis

This case report describes the treatment of a 33-year-old white man who had a skeletal Class III and dental Class II subdivision malocclusion caused by a retrognathic maxilla, with severe maxillary crowding, a highly placed maxillary left canine, mild mandibular crowding, and a bilateral posterior crossbite. Treatment was performed with a modified surgery-first approach, which included a short presurgical alignment phase for the correction of the significant maxillary crowding while controlling the incisal angulation, followed by LeFort I maxillary advancement surgery. The short presurgical orthodontic phase aimed at eliminating the anterior dental interferences before the maxillary advancement, and the use of the inherent increased bone turnover in the postsurgical phase helped to reduce the total orthodontic treatment time to 12 months. Pleasing esthetic results and a good functional occlusion were achieved.