Treatment Of Unilateral Posterior Crossbite Research Articles

Treatment of unilateral posterior crossbite with Maurício Vaz de Lima appliance – case report

Posterior crossbite (PCB) is a common malocclusion and its diagnosis must be careful, because only knowing its etiology can determine the treatment plan. The PCB can be dental, skeletal or functional. For each subtype, there is a specific treatment. The aim of this study was to report the treatment of two patients with Skeletal Unilateral Posterior Crossbite. The patients were treated with the same device, a Maurício expander with a Hawley arch. The technique employed, following the Knowledge of Jaw Functional Orthopedics (JFO), proved to be extremely efficient, allowing correction of crossbite malocclusion, mandible centralization, correct dental positioning, restoring conditions so that the growth and development of the patients occurred in a correct and balanced way.

Evaluation of effects of a modified asymmetric rapid maxillary expansion appliance on the upper airway volume by cone beam computed tomography

Background/purposeThe rapid maxillary expansion is accepted as the gold standard for the treatment of unilateral posterior crossbite in growing children. This study used cone beam computed tomography (CBCT) to evaluate the effects of a modified asymmetric rapid maxillary expansion (ARME) appliance on the upper airway volumes. Materials and methodsA modified ARME appliance was used on 12 adolescent male patients (mean age: 13.92 ± 0.82 years) with a class I skeletal relationship and posterior unilateral crossbite. Lateral cephalometric measurements and upper airway volume were evaluated using CBCT images. The posterior airway volumes of the oropharyngeal and nasopharyngeal airways were measured. ResultsCephalometric measurements showed significant (P < 0.05) posterior rotation of the mandible. There was no significant movement of the maxilla according to the cranial base on the sagittal plane. Nasopharyngeal and oropharyngeal airway volumes increased significantly (P < 0.05). ConclusionThe results of this study demonstrate that treatment with the modified ARME has no significant effect on the maxilla but may increase the upper airway volume.

A systematic review concerning early orthodontic treatment of unilateral posterior crossbite.

The aim of this study was to assess the orthodontic treatment effects on unilateral posterior crossbite in the primary and early mixed dentition by systematically reviewing the literature. A literature search was performed by applying the Medline database (Entrez PubMed) and covering the period from January 1966 to October 2002. The inclusion criteria were primary and early mixed dentition with unilateral posterior crossbite, randomized controlled trials (RCT), prospective and retrospective studies with concurrent untreated as well as normal controls, and clinical trials comparing at least two treatment strategies without any untreated or normal group involved. Two reviewers extracted the data independently and also assessed the quality of the studies. The search strategy resulted in 1001 articles, and 12 met the inclusion criteria. Two RCTs of early treatment of crossbite have been performed, and these two studies support grinding as treatment in the primary dentition. There is no scientific evidence available to show which of the treatment modalities, grinding, Quad-helix, expansion plates, or rapid maxillary expansion, is the most effective. Most of the studies have serious problems of lack of power because of small sample size, bias and confounding variables, lack of method error analysis, blinding in measurements, and deficient or lack of statistical methods. To obtain reliable scientific evidence, better-controlled RCTs with sufficient sample sizes are needed to determine which treatment is the most effective for early correction of unilateral posterior crossbite. Future studies should also include assessments of long-term stability as well as analysis of costs and side effects of the interventions.

Maxillary Orthodontic Expansion Assisted by Unilateral Alveolar Corticotomy and Low-Level Laser Therapy: A Novel Approach for Correction of a Posterior Unilateral Cross-Bite in Adults.

Introduction: The treatment of a true unilateral posterior crossbite often requires asymmetric maxillary expansion; however, this is challenging to achieve with conventional expansion methods because of several biomechanical limitations. In this paper, we introduce a new protocol for the treatment of a unilateral posterior crossbite in adults based on maxillary orthodontic expansion assisted by corticotomy and low-level laser therapy (LLLT) performed on the crossbite side. Methods: The study sample included 15 adults (8 females, 7 males) affected by a true unilateral posterior crossbite, with a mean age of 21.6 ± 3.1 years at the at the beginning of treatment. After the application of orthodontic appliances (palatal expander and self-ligating brackets), corticomy was performed at the buccal aspect of the crossbite side while LLLT was monthly administered up to the correction of the crossbite. The efficacy of the technique was evaluated through measurements performed on maxillary digital models. Results: All subjects reported successful correction of the posterior unilateral crossbite, and functional occlusion was achieved as well. The average expansion was greater at the crossbite side compared to the unaffected side and such difference was significant at the levels of first premolars (P < 0.05), second premolars (P < 0.05) and first molars (P < 0.05). Conclusion: Orthodontic maxillary expansion assisted by unilateral corticotomy and LLLT was effective in the treatment of the true unilateral crossbite.

An RCT on clinical effectiveness and cost analysis of correction of unilateral posterior crossbite with functional shift in specialist and general dentistry.

To evaluate the costs of quad-helix (QH) and removable expansion plate (EP) treatments performed either in specialist or general dentistry for the correction of unilateral posterior crossbite with functional shift in the mixed dentition. Four-arm parallel group multicentre randomized controlled trial. One hundred and ten patients with unilateral posterior crossbite with functional shift were recruited. The patients were randomized by an independent person not involved in the trial. The randomization used blocks of 20 and into the following four groups: QH treatments in specialist orthodontic clinics (QHS), QH treatments in general dentistry (QHG), EP treatments in specialist orthodontic clinics (EPS), and EP treatments in general dentistry (EPG). Blinding was accomplished of the outcome assessor and data analyst. A cost analysis was performed with reference to intention-to-treat (ITT), regarding direct costs, indirect costs, and societal costs (the sum of direct and indirect costs) for calculations of successful treatments alone and for retreatments when required. To determine which alternative has the lower cost, a cost-minimization analysis was undertaken, based on that the outcome of the treatment alternatives were broadly equivalent, so the difference between them reduces to a comparison of costs. In the QHS group, 28 of 28 patients were successfully corrected compared to 23 of 27 in the QHG group. Treatment with expansion plate was less successful: 18 of 27 patients in the EPS group and 18 of 28 in the EPG group. QH treatment performed in specialist orthodontic clinics had significantly lower costs than QH or EP treatment accomplished in general dentistry as well as EP treatments in specialist orthodontic clinics. Costs depend on local factors and should not be directly extrapolated to other locations. Treatment of unilateral posterior crossbite in the mixed dentition is recommended to be performed by a specialist orthodontist using the QH appliance. The trial was not registered.

A new method for the treatment of unilateral posterior cross-bite: a three-dimensional finite element stress analysis study

BackgroundStress relieving corticoto mies during the treatment of maxillary expansion are needed in adult patients.MethodsThree-dimensional (3D) finite element model was prepared, and finite element analysis was processed to evaluate the stress distributions within the skull and maxillary teeth during surgically assisted rapid maxillary expansion (SARME) treatment.ResultsExpansion forces generated more stress on the corticotomy-applied part of the maxilla. The stress levels decreased dramatically above the corticotomy line.ConclusionAsymmetric transveral maxillary expansion might be achieved from a symmetric force generating screw during SARME treatment. SARME osteotomies may concentrate the stress in the expanding maxilla and reduce the pain in other parts of the cranium.

Evaluation of masticatory muscle activity in patients with unilateral posterior crossbite before and after rapid maxillary expansion.

The relationship between unilateral posterior crossbite (UPCB) and the possible asymmetric activation of the jaw muscles in children is still under debate. This study aimed at evaluating the jaw muscle activity of children with UPCB before and after rapid maxillary expansion (RME) by means of surface electromyography and a standardized sampling protocol. Twenty-nine children with UPCB (UPCB-group, mean age 9.6 ± 1.6 years) and 40 UPCB-free controls (Control-group, 10.5 ± 1.1) were recruited. The activity of the left and right anterior temporalis (AT) and superficial masseter muscles (MM) was recorded during maximum voluntary clenching and a chewing task (T0). In the UPCB-group, data were collected, also, after the correction of the UPCB with RME (T1) and 6 months later (T2), without any further treatment. Electromyographic indices comparing the activity of paired muscle were computed via software to estimate the extent of asymmetric AT and MM activity. Paired and unpaired t-test or Wilcoxon-signed rank and Mann-Whitney U test, ANOVA or Friedman test and chi-squared test were used in the statistical analysis. Both groups presented with asymmetric activity of the muscles, which did not differ between groups (T0, all P > 0.05). The treatment determined a decrease in muscular activity (T1, P = 0.040), and a more asymmetric pattern of muscle activation during chewing (T1, P = 0.040), which returned similar to baseline values at T2 (all P > 0.05). UPCB does not contribute to an asymmetric activation of AT and MM during functional tasks. The treatment of UPCB by RME did not determine a more symmetric activity of the assessed muscles.

Three-dimensional assessment of palatal change in a controlled study of unilateral posterior crossbite correction in the primary dentition

The aim of this study was to quantify the palatal change in three groups of children: children with a unilateral posterior crossbite (TCB) who were treated, children with untreated unilateral posterior crossbite (UCB), and children without a crossbite (NCB). Study casts of 60 Caucasian children in the primary dentition (20 TCB, 20 UCB, and 20 NCB), aged 5.4 ± 0.7 years, were collected at baseline (T1) and at 1-year follow-up (T2). Both TCB and UCB groups had unilateral posterior crossbite and midline deviation. The TCB group was treated using a cemented acrylic splint expander in the upper arch. The study casts were scanned using a laser scanner and palatal surface area, palatal volume, and symmetry of the palatal vault were evaluated and compared between the three groups. At T1, the palatal volume of TCB (2698 mm(3)) and UCB (2585 mm(3)) was significantly smaller than that of NCB (3006 mm(3); P < 0.05, analysis of variance test). After treatment, the palatal volume of the TCB group (3087 mm(3)) increased and did not differ from the NCB group (3208 mm(3)), whereas the UCB (2644 mm(3)) had a significantly smaller palatal volume than the NCB or TCB groups (P < 0.05). The increase of palatal volume in the TCB group (389 mm(3)) was significantly greater than in the UCB (59 mm(3)) and NCB (202 mm(3)) groups. The symmetry of the palatal vault was greater than 90 per cent in all three groups at T1 and at T2. Treatment of unilateral posterior crossbite in the primary dentition has a significant effect, particularly on the palatal volume increase.

Three-dimensional evaluation of early crossbite correction: a longitudinal study

The aim of this longitudinal study was to assess whether correction of unilateral posterior crossbite in the primary dentition results in improvement of facial symmetry and increase of palatal surface area and palatal volume. A group of 60 Caucasian children in the primary dentition, aged 5.3 ± 0.7 years, were collected at baseline. The group consisted of 30 children with a unilateral posterior crossbite with midline deviation of at least 2 mm (CB) and 30 without malocclusion (NCB). The CB group was treated using an acrylic plate expander. The children's faces and dental casts were scanned using a three-dimensional laser scanning device. Non-parametric tests were used for data analysis to assess differences over the 30 months period of follow-up. The CB children had statistically significantly greater facial asymmetry in the lower part of the face (P < 0.05) and a significantly smaller palatal volume (P < 0.05) than the NCB children at baseline. There were no statistically significant differences between the two groups at 6, 12, 18, and 30 months follow-ups. Treatment of unilateral posterior crossbite in the primary dentition period resulted in an improvement of facial symmetry in the lower part of the face (P < 0.05) and increase of the palatal surface area and palatal volume (P < 0.001). At 30 months, relapse was observed in eight children (26.7 per cent). Treatment of unilateral posterior crossbite in the primary dentition improves facial symmetry and increases the palatal surface area and the palatal volume, though it creates normal conditions for normal occlusal development and skeletal growth.

Slow or rapid palatal expansion for early treatment of unilateral posterior crossbite? Evaluation of the reverse chewing cycles correction

Objectives It is well established that patients with a unilateral posterior crossbite, when chewing on the affected side, show an increased frequency of reverse chewing cycles. It was hypothesized that the correction of reverse cycles may be due to the characteristics of the therapy. The aim was to investigate the prevalence of reverse chewing patterns in children with unilateral posterior crossbite before and after treatment with Function Generating Bite (FGB). Materials and methods Twenty children, (9 boys, 11 girls; age, mean ± SD, 7.5 ± 1.1), 10 with a right and 10 with a left posterior unilateral crossbite were selected. Mandibular movements during chewing soft and hard boluses were measured with a kinesiograph (K7 -I, Myotronics Inc. Tukwila, Washington, USA). Results The results showed a significant difference when comparing the percentage of reverse chewing patterns, before and after therapy with FGB, during chewing on the crossbite side both with soft and hard bolus (p < 0.0001). No significant differences were observed during chewing on the non-crossbite side. Discussion The results of this study confirmed that FGB corrects both the dental and functional asymmetries. Knowing that the rapid palatal expansion does not correct the masticatory function, it is of clinical relevance, for the orthodontists, the knowledge and the understanding of the functional outcomes with different therapies. Conclusions The type of treatment and the biomechanics of the appliance used are of great importance for the correction of the reverse chewing cycles and for rebalancing the functional asymmetry of children with unilateral posterior crossbite.

Treatment of unilateral posterior crossbite with mandibular shift: a case report

A 17-year-old boy had a skeletal Class III malocclusion with facial asymmetry, a unilateral posterior crossbite and functional shift of the mandible to the left on closure. There was bilateral constriction of the maxilla and crowding in both of the arches. The patient was treated orthodontically with an edgewise appliance and a bonded Hyrax for maxillary expansion. The result of the orthodontic treatment was facial symmetry and optimal occlusion. At the one year follow-up, the condition had been maintained.

Grinding is effective in early orthodontic treatment of unilateral posterior crossbite

PubMed and the Cochrane Controlled Clinical Trials Register were searched. Reference lists from retrieved articles were also searched by hand for additional studies. For inclusion, an article had to satisfy the following criteria: cases in primary and early mixed dentition with unilateral posterior crossbite; be a randomised controlled trials (RCT) or prospective and retrospective studies with concurrent untreated as well as normal controls; clinical trials must have compared at least two treatment strategies without any untreated or normal control group involved; and be written in English, German, French or a Scandinavian language. Data extraction was carried out independently and in duplicate. Quality of the studies was assessed and categorised as low, medium and high. Interexaminer conflicts were resolved by discussion to reach a consensus. The search identified 1001 articles, of which 12 met the inclusion criteria. Only two RCT of early treatment of crossbite have been performed, and these two studies support grinding as treatment in the primary dentition. As treatment strategies, quad-helix (QH), expansion plates and rapid maxillary expansion (RME) are effective in the early mixed dentition with high success rates. There is, however, no scientific evidence available that shows which of the treatment modalities, that is, grinding, QH, expansion plates or RME, is the most effective. Most of the studies have the serious drawback of lack of power because of small sample size, bias and confounding variables, lack of method error analysis and blinding in measurements, and deficient or lack of statistical methods. Thus, the studies were not of high enough quality level to draw any evidence-based conclusions. Better-controlled RCT with sufficient sample sizes are needed to obtain reliable scientific evidence identifying which treatment is the most effective for early correction of unilateral posterior crossbite. Future studies should also include assessments of long-term stability as well as analysis of costs and side-effects of the interventions.

Bite force in pre-orthodontic children with unilateral crossbite.

In the present study bite force was examined in pre-orthodontic children with unilateral posterior crossbite and compared with an age- and sex-matched control group. The sample comprised 52 children aged 7-13 years, 26 pre-orthodontic children with unilateral posterior crossbite (crossbite group), and 26 children with neutral occlusion (control group). Unilateral bite force was measured at the first molar by means of a pressure transducer. Furthermore, symptoms and signs of temporomandibular disorders (TMD) and number of teeth in contact in the intercuspal position (ICP) were recorded. In both groups, the maximum bite force increased significantly with age and with increasing stages of dental eruption, but the bite force in both sexes did not differ significantly. There were no significant differences in bite force between sides, but this was significantly smaller in the crossbite group than in the controls (P < 0.001). Regression analysis showed that stage of dental eruption (P < 0.001), number of teeth in occlusal contact (P < 0.01), and unilateral crossbite (P < 0.001) were the only variables significantly correlated with bite force. The number of teeth in contact was significantly smaller in the crossbite group than in the controls (P < 0.05) and the frequency of muscle tenderness was significantly higher in the crossbite group than in the controls (P < 0.05). These results suggest that differences in the muscle function associated with unilateral crossbite lead to a significantly smaller bite force in the crossbite group compared with controls and this difference did not diminish with age and development. These findings indicate that early treatment of unilateral posterior crossbite is advisable to optimize conditions for function.

Treatment of unilateral posterior crossbite with quad-helix and removable plates: A retrospective study: Harry Hermanson, Juri Kurol, and Assar RönnermanEur. J. Orthod. 1985;7:87–102

Treatment of unilateral posterior crossbite with quad-helix and removable plates: A retrospective study: Harry Hermanson, Juri Kurol, and Assar RönnermanEur. J. Orthod. 1985;7:87–102