Muscular and condylar response to rapid maxillary expansion. Part 2: magnetic resonance imaging study of the temporomandibular joint

Three-dimensional assessment of the maxilla after modified surgically assisted rapid expansion: a retrospective study

OBJECTIVE

This retrospective study aims to assess the three-dimensional dentoskeletal effects and median palatal suture opening pattern in patients undergoing modified surgically assisted maxillary rapid expansion (SARME) without pterygoid plate detachment.

METHODS

Twenty-eight patients submitted to modified SARME between 2009 and 2016 were retrospectively evaluated through cone-beam computed tomography (CBCT). Dental and skeletal measurements were taken at three different operative periods (before the expansion - T0; at the end of the activation of the Hyrax device - T1; and six months after the immobilization of the device - T2). Statistical analyses, including ANOVA and Pearson's correlation coefficient, were performed using SPSS software.

RESULTS

SARME demonstrated significant transverse maxillary expansion (with an average of 6.05 mm) with a greater impact in the anterior region. Dental measurements, including canine and molar distances, exhibited significant changes over the operative periods. Bone measurements (ANS and PNS) presented small but significant alterations, including a slight inferior displacement of ANS during device activation. The nasal floor width increased, followed by a width reduction after immobilization. The median palatal suture predominantly exhibited a Type II (V-shaped) opening.

CONCLUSION

The modified SARME presented a transversal direction increase and a super-lower skeletal displacement, with the anterior region being more affected than the posterior region. There was no change in the anteroposterior direction of the maxilla. Additionally, there was an increase in the linear dental measurements and a decrease in the angular measurement, with a positive correlation between the amount of posterior bone expansion and molar expansion as a result of the treatment in the analyzed period.

TMJ anterior disc displacement anchorage surgery: a retrospective study based on a suture-free titanium screw strategy

OBJECTIVE

To evaluate the feasibility and effectiveness of using a suture-free titanium screw in repositioning anterior disc displacement without reduction (ADDwoR) of the temporomandibular joint (TMJ).

METHODS

A consecutive sample of twelve patients (fifteen joints) was included in this study. All patients were diagnosed with ADDwoR and showed limited mouth opening or temporomandibular joint pain symptoms. Suture-free titanium screw was placed in the condyle directly following the disc repositioning. Pre- and postoperative evaluation parameters include operation time, the visual analogue scale for pain (VAS), lateral excursion movements (LEM), maximum interincisal opening (MIO), and disc length and position on MRI. In addition, the mandibular condyle height was also measured. Statistical significance was considered when p < 0.05.

RESULTS

The unilateral operation time was 58.54 ± 5.43 min; during the 6-month period after the operation, the VAS values decreased from 87 ± 6.34 to 14.08 ± 6.65. The MIO increased from 30.07 ± 4.73 to 39.89 ± 1.69 mm (p = 0.01). The TMJ disc length was prolonged from 8.23 ± 1.12 to 11.51 ± 1.29 mm. The condyles showed significant remodeling, and the height of the condyle increased from 18.24 ± 4.12 increase to 19.6 ± 4.31 mm. The LEM was increased from 5.27 ± 0.51 to 6.36 ± 0.62 mm. The MRI images showed the stability of the disc in position during the opening and closing of the mouth. The TMJ disc position was stable during the follow-up period.

CONCLUSION

Anteriorly displaced articular disc can be repositioned by a suture-free titanium screw strategy. This technique is an alternative method to address ADDwoR.

Effect of Molar Distalization on Condyle-Glenoid Fossa Relationship

Objective

It is essential to be aware of the potential effects of orthodontic treatment on tissues and anatomical structures associated with the masticatory system, especially the temporomandibular joint (TMJ). Little information is available about the consequences of molar distalization on the TMJ. Therefore, this study is aimed at investigating the changes of the condyle-fossa relationship after molar distalization using the distal jet appliance.

Materials and Methods

The sample consisted of twenty-five patients (mean age 20.4 ± 2.6) who underwent molar distalization by the distal jet appliance. CBCT scans were taken before (T0) and after (T1) the completion of the molar distalization. Joint spaces (anterior, superior, and posterior) and cephalometric vertical angles (SN.GOME and Björk sum) were measured and compared at T0 and T1.

Results

Superior and posterior joint spaces increased significantly after molar distalization (PS 0.29 mm, P < 0.001, SS 0.06 mm, P < 0.5). Vertical cephalometric angles also increased after molar distalization by the distal jet appliance (SN.GOME 0.92°, Björk 1.11°).

Conclusion

There was a statistically significant increase in the superior and posterior joint spaces after molar distalization. However, this increase may not be of clinical importance. The vertical dimension has also increased.

Condylar morphology and position changes after miniscrew-assisted rapid palatal expansion in skeletal Class III malocclusion adult patients with mandibular deviation and unilateral posterior crossbite

BACKGROUND

To evaluate the morphological and positional changes of mandibular condyle after miniscrew-assisted rapid palatal expansion (MARPE) in skeletal Class III malocclusion adult patients with horizontal mandibular deviation (MD).

METHODS

The sample consisted of 15 patients with MD (6 males and 9 females, mean age 21.58 ± 3.12 years). The CBCT scans were taken before and after MARPE immediately. The pre- and post-registered images of the cranial base and mandible were measured, respectively, by Mimics.

RESULTS

After expansion, the distance between superior condylar point and the Frankfort horizontal plane on the deviated side and the non-deviated side increased by 0.96 ± 0.60 mm (P = 0.011) and 0.70 ± 0.65 mm (P = 0.046); coronal condylar angle of the deviated side increased by 0.39° ± 0.34 (P = 0.028) and 0.06° ± 0.49 (P = 0.917) on the non-deviated side. No statistically significant differences were found when comparing the condylar position on both sides before and after treatment. The degree of mandibular deviation decreased 0.43 mm (P = 0.270).

CONCLUSIONS

This study suggested that for skeletal Class III malocclusion adult patients with horizontal MD, the condyle on the deviated side rotated toward the non-deviated side in the coronal direction; the condylar remodeling occurred mainly on the deviated side after MARPE in the vertical direction.

Cone beam computed tomographic evaluation of the changes in condylar position in growing patients with unilateral posterior crossbite undergoing rapid maxillary expansion followed by fixed orthodontic therapy

PURPOSE

This study aimed at assessing changes in condylar position (CP) in growing patients with unilateral posterior crossbite (UPC) undergoing rapid maxillary expansion (RME) followed by fixed orthodontic treatment (FOT) (experimental-group); and growing patients without posterior crossbite (PC) treated with FOT alone (control-group).

METHODS

Cone beam computed tomography (CBCT) images were obtained before treatment (T0), 6 months after RME (T1) and after FOT (T2) for the experimental-group (n = 19); and at T0 and T2 for the control-group (n = 22). Condylar position-related measurements including the anterior joint space (AJS), superior joint space (SJS), posterior joint space (PJS), lateral position of condyle (LC) and condylar angle (CA) were measured. Non-parametric tests were used.

RESULTS

On the crossbite side, significant increases were found in LC (P = 0.039) and CA (P = 0.007), and on the non-crossbite side significant increases were observed in SJS (P = 0.027) and LC (P = 0.001) between T0, T1 and T2 in patients with UPC. On the right and left sides in the control-group, significant increases were identified in LC (P < 0.001 and P = 0.012, respectively) between T0 and T2.

CONCLUSIONS

In growing patients with UPC, RME followed by FOT is associated with significant changes in CP-related measurements.

Condylar Changes in Children with Posterior Crossbite after Maxillary Expansion: Tridimensional Evaluation

(1) Background: To investigate condylar position in subjects with functional posterior crossbite comparing findings before and after rapid maxillary expansion (RME) treatment through 3D analysis; (2) Methods: Thirty-two Caucasian patients (14 males, mean age 8 y 8 m ± 1 y 2 m; 18 females mean age 8 y 2 m ± 1 y 4 m) with functional posterior crossbite (FPXB) diagnosis underwent rapid palatal expansion with a Haas appliance banded on second deciduous upper molars. Patients’ underwent CBCT scans before rapid palatal expansion (T0) and after 12 months (T1). The images were processed through 3D slicer software; (3) Results: The condylar position changes between T1 and T0 among the crossbite and non-crossbite sides were not statistically significant, except for the transversal axis. At T1, the condyles moved forward (y axis) and laterally (x axis), they also moved downward (z axis) but not significantly; (4) Conclusions: Condilar position in growing patients with functional posterior crossbite did not change significantly after rapid maxillary expansion.

Comparison of the effects of rapid maxillary expansion versus Twin Block appliance on mandibular growth in skeletal Class II patients

Background

This is a retrospective study that compares mandibular growth changes in skeletal Class II patients treated by rapid maxillary expansion (RME) and following fixed appliance with those patients treated by Twin-Block (TB) and following fixed appliance.

Methods

Fourteen patients treated by RME and following fixed appliance were included into the RME group. Fifteen patients treated by Twin-Block and following fixed appliance were included into the TB group. Lateral cephalometric radiographs taken before treatment and immediately after fixed appliance treatment were used to evaluate mandibular growth effects.

Results

The starting forms of the patients in the two groups were examined to be of good comparability. The mandibular length increased significantly in both groups as measured by Co-Gn, Go-Gn and Ar-Gn, but the TB group didn’t show more mandibular growth than the RME group (P > 0.05). Skeletal changes of the mandible in vertical dimension were different in the two groups. The change in FMA was 0.35° in the RME group, while the change was 2.65° in the TB group (P < 0.001). The change in LAFH was 5.14 mm in the RME group, significantly smaller than the change of 10.19 mm in the TB group (P < 0.001).

Conclusion

The investigated Phase I treatment with RME followed by Phase II treatment of fixed appliance achieved the same increases in sagittal mandibular growth and facial profile improvements as the Twin-Block therapy. The treatment with RME followed by fixed appliance was better for vertical control, while the treatment with Twin-Block followed by fixed appliance significantly increased the mandibular plane angle.

Effects of rapid maxillary expansion on temporomandibular joints

OBJECTIVE

To evaluate the impact of rapid maxillary expansion (RME) on the condylar position, disc joint, joint space, and interarticular relationship in growing patients.

MATERIALS AND METHODS

A systematic search was performed in nine databases. The clinical studies selected included those with pre- and post-magnetic resonance, conventional computed tomography or cone beam tomography in growing patients. Risk of bias assessment was performed using the Cochrane Collaboration tool for controlled clinical studies and National Heart, Lung, and Blood Institute (NHLBI) Quality Assessment for Before-After Studies With No Control Group.

RESULTS

Initially, 4303 records were identified. Only eight studies fulfilled the criteria and were included in the qualitative analysis. Of those, two were controlled clinical studies with a risk of uncertain to high bias. The remaining papers had a low to moderate risk of bias. Results showed that RME in children and adolescents promoted the following: remodeling in the head and or condylar branch, changes in condylar position and joint space, maintenance of improved symmetry between the condyles, and no ability to modify the position or shape of the articular disc.

CONCLUSIONS

RME in growing patients is able, in the short term, to modify the condyle-fossa relationship but does not change the position or shape of the articular disc. The intercondylar symmetric relationship is maintained or improved. Although the NHLBI score shows low to moderate risk of bias, the clinical relevance of these review findings is limited by Cochrane and Grades of Recommendation, Assessment, Development and Evaluation scores.

Transverse Skeletal Effects of Rapid Maxillary Expansion in Pre and Post Pubertal Subjects: A Systematic Review

OBJECTIVE

The aim of this systematic review was to assess the transverse skeletal effects of rapid maxillary expansion (RME) in pre and post-pubertal subjects.

MATERIAL AND METHODS

Five databases were searched till May 2018; Pubmed, Cochrane, Scopus, Lilacs and Web of science in addition to the manual search of other sources. There were no language restrictions. Methodological Index for Non-Randomized Studies MINORS was used to assess the quality and risk of bias of the trials included.

RESULTS

Six studies were finally included in the qualitative analysis. A meta-analysis wasn't performed due to the heterogeneity of methodologies and outcomes. All of the included studies showed drawbacks in their structure yielding weak evidence. On the short term, RME caused an increase in the maxillary and lateral-nasal widths in pre-pubertal subjects by 3.4 mm and 3.3 mm, and by 2.8 and 2.2 mm respectively in post-pubertal subjects. Although statistically insignificant, the maxillary width increase was more than that of the post-pubertal subjects by 0.6 mm. Over the long term, expansion produced permanent increases in the transverse dimensions of both the dento-alveolar and skeletal components of the maxilla and circum-maxillary structures in pre-pubertal subjects. The post-pubertal subjects presented with a statistically significant increase only in the later-nasal width by 1.3 mm than the untreated controls with no permanent increase in the skeletal maxillary width.

CONCLUSION

The literature is very deficient regarding the use of skeletal age as a reference in the treatment of skeletal crossbites using RME. Only weak evidence exists supporting the increased maxillary and lateral-nasal widths after tooth-tissue borne RME in pre-pubertal subjects, with these effects being less in the post-pubertal ones.

The difference of stress distribution of maxillary expansion using rapid maxillary expander (RME) and maxillary skeletal expander (MSE)-a finite element analysis

Background

Maxillary skeletal expander (MSE) in combination with miniscrews was developed to overcome the drawbacks that may have resulted from the application of conventional rapid maxillary expander (RME). This research was conducted to analyze the difference of stress distribution of maxillary expansion using RME and MSE in the region of interests (ROIs): first molars (M1), palatal alveolar bones of M1, palatine sutures, zygomatic sutures, miniscrews, and their surrounding bones.

Methods

A dry skull was scanned using CBCT and rendered into a three-dimensional (3D) model of craniomaxillary structures. The data analysis was done both visually and numerically.

Result

The stress distributions in RME group were located at the palatal side of M1, mesial side of palatal alveolar of M1, pulp chamber of M1, and inferior cortex of palatine sutures. The stress distributions in the MSE group were located at the distopalatal cusp of M1, palatal side of palatal alveolar of M1, and inferior and superior cortex of palatine sutures. The stress distributions in zygomatic sutures on both groups were located at the zygomaticotemporal sutures, whereas in the miniscrews, the stress were located at the anterior miniscrews and palatal side of surrounding bones.

Conclusions

There were significant differences of stress distribution of maxillary expansion measured in the ROIs in the craniomaxillary 3D model using RME and MSE.

Longitudinal effects of rapid maxillary expansion on masticatory muscles activity

BACKGROUND

To investigate the modifications induced by rapid maxillary expansion (RME) on the electromyographic (EMG) activities of the anterior temporal and superficial masseter muscles, in patients without pre-treatment EMG alterations.

MATERIAL AND METHODS

Twenty-one patients with unilateral posterior cross-bite selected from the orthodontic department of the University of L'Aquila (Italy), were enrolled. There was no control group in this study since each subject acted as a control of her/himself. Two surface EMG recordings were taken: T0 (before RME) and at T1 (3 month after the end of expansion). To verify the neuromuscular equilibrium, the EMG activities of both right and left masseter and anterior temporal muscles were recorded during a test of maximum clench. EMG indexes were compared by paired Student's t-test.

RESULTS

In both occasions, all indices showed a good symmetry between the right and left side masticatory muscles. No statistically significant differences were found between the two recordings.

CONCLUSIONS

In children without pre-treatment EMG alterations, no variations in standardized muscular activity after RME were found. The treatment did not alter the equilibrium of the masseter and temporal muscles. Key words:Rapid maxillary expansion, electromyography, masticatory muscles.

Condylar positional changes in rapid maxillary expansion assessed with cone-beam computer tomography

OBJECTIVES

The aim of this study was to determine the presence of condylar spatial changes in patients having rapid maxillary expansion treatments compared to a control group.

METHODS

Thirty-seven patients with maxillary transverse deficiency (11-17 years old) were randomly allocated into two groups (one treatment group - tooth borne expander [hyrax] - and one control group). Cone-beam computer tomographies (CBCT) were obtained from each patient at two time points (initial T1 and at removal of appliance at 6 months T2). CBCTs were analyzed using AVIZO software and landmarks were placed on the upper first molars and premolars, cranial base, condyles and glenoid fossa. Descriptive statistics, intraclass correlation coefficients and one-way Anova analysis were used to determine if there was a change in condyle position with respect to the glenoid fossa and cranial base and if there was a statistically significant difference between groups.

RESULTS

Descriptive statistics show that changes in the condyle position with respect to the glenoid fossa were minor in both groups (<1.9mm average for both groups). The largest difference in both groups was found when measuring the distance between the left and right condyle heads. When comparing changes between both groups, no statistically significant difference was found between changes in the condyles (P<0.05).

CONCLUSION

Rapid maxillary expansion treatments present mild effects/changes on the condylar position. Nevertheless, these changes do not present a significant difference with controls, thus not constituting a limitation for applying this treatment.

Impact of midface and upper face fracture on bite force, mandibular mobility, and electromyographic activity

This study evaluated the bite force, electromyographic activity, and mandibular mobility in patients undergoing surgery for facial fracture treatment that required a coronal approach. Ten men were divided into two groups: group I, coronal approach with pre-auricular extension (n=4, average age 34.5 years); group II, coronal approach (n=6, average age 24.8 years). The maximum bite force was measured using a dynamometer and mandibular mobility using a calliper. The electromyographic activity of the right masseter (RM), left masseter (LM), right temporal (RT), and left temporal (LT) muscles was evaluated using a Myosystem-Br1 apparatus. Patients were evaluated at 1, 2, 3, and 6 months after surgery. Data were analysed using the repeated measures test (SPSS 21.0; P≤0.05). Statistically significant differences were found for electromyographic activity at rest (group II: LM P=0.00), left laterality (group I: RT P=0.02; group II: RT P=0.04), and maximum voluntary contraction (group I: RM P=0.04 and RT P=0.04; group II: RM P=0.05, LM P=0.00, and LT P=0.01 and for maximum molar bite force in the right (group I, P=0.00; group II, P=0.01) and left (group II, P=0.01) molar regions. The subjects regained electromyographic activity, maximum bite force, and mandibular mobility throughout the period evaluated.

Evaluation of the effects of modified bonded rapid maxillary expansion on occlusal force distribution: A pilot study

Objective:

To evaluate the effects of modified bonded rapid maxillary expansion (RME) on occlusal force distribution.

Materials and Methods:

The sample included 12 patients (7 girls and 5 boys; mean age: 13.1 years) at the permanent dentition stage with bilateral posterior cross-bite. The patients were treated with a modified bonded RME appliance, activated twice a day. The study was terminated when the palatal cusps of the maxillary posterior teeth were occluding with the buccal cusps of the mandibular posterior teeth. The postretention period was 3 months. The T-Scan III device was used to analyze the percentages of occlusal force distribution, and records were taken at the pretreatment (T1), the postreatment (T2), and the postretention (T3) periods. Wilcoxon signed rank test was used for statistical analyses.

Results:

Incisors were most frequently without contact, followed by canines. The highest forces were seen in the second and first molar regions. A significant decrease was seen in total occlusal force during treatment (T1–T2); however, during retention, the force returned to its initial value, and no significant differences were found (T1–T3). No differences were found between right and left sides and in occlusal forces of the teeth in all time periods.

Conclusion:

The use of modified bonded RME decreases the total occlusal forces during the treatment period, but it does returns to its initial value after the postretention period.

Imaginologia da articulação temporomandibular durante o tratamento ortodôntico: uma revisão sistemática

INTRODUÇÃO: a evolução da Imaginologia na Odontologia propiciou uma série de vantagens para o diagnóstico e elaboração de planos de tratamento em diversas especialidades. Exames como ressonância magnética nuclear, tomografia computadorizada e tomografia volumétrica Cone Beam, bem como métodos de reconstrução em 3D, permitiram analisar de forma precisa estruturas orofaciais.Aliado a esse fato,com a realização de estudos clínicos com metodologias e desenhos adequados, pode-se avaliar os efeitos do tratamento ortodôntico sobre a articulação temporomandibular (ATM). OBJETIVO: esse trabalho, através de uma revisão sistemática de literatura, teve como objetivo analisar a inter-relação entre o tratamento ortodôntico e a ATM, verificando se a Ortodontia acarreta alguma alteração das estruturas internas da ATM. MÉTODOS: levantamento em bases de pesquisa (MEDLINE, Cochrane, EMBASE, Pubmed, Lilacs e BBO), entre os anos de 1966 e 2009, com enfoque em estudos clínicos randomizados, estudos longitudinais prospectivos não randomizados, revisões sistemáticas e meta-análises. RESULTADOS: após a aplicação dos critérios de inclusão, chegou-se a 14 artigos, sendo que 2 eram estudos clínicos randomizados e 12 eram estudos longitudinais sem critérios de randomização. CONCLUSÕES: pela análise da literatura, conclui-se que a realização do tratamento ortodôntico não ocorre à custa de posicionamentos não fisiológicos do côndilo e disco articular. Algumas mecânicas podem acarretar remodelações dos componentes ósseos articulares.

Prevalence of temporomandibular dysfunction in orthodontic treatment

The aim of our study was to investigate the prevalence of temporomandibular dysfunction (TMD) during orthodontic treatment.

MATERIAL AND METHOD

the study investigated all the patients receiving orthodontic treatment in the dentofacial orthopedic department in Casablanca in the course of the different stages of treatment over a 4-month period. We looked for a possible association between the presence of at least one sign of TMD, the Helkimo anamnesis index, the clinical Helkimo index and the following factors: age, gender, extractions, or not, of premolars, duration, type and stage of orthodontic treatment, molar and canine class, crowding, overjet, overbite and unilateral crossbite. Data were analysed using Epi-info 6.0.fr software. The analysis of the results was done using the Chi(2) test (P<0.05).

RESULTS AND CONCLUSION

no statistically significant association could be established between TMD and the various factors under investigation with the exception of the association between gender and the Helkimo anamnesis index, stage of treatment and the Helkimo anamnesis index and the Angle molar class and the Helkimo clinical index.