Editor's Summary, Q &amp; A, Reviewer's Critique

OBJECTIVE: The aim of this randomized clinical trial was to evaluate the dental, dentoalveolar, and skeletal changes occurring right after the rapid maxillary expansion (RME) and slow maxillary expansion (SME) treatment using Haas-type expander. METHODS: All subjects performed cone-beam computed tomography (CBCT) before installation of expanders (T1) and right after screw stabilization (T2). Patients who did not follow the research parameters were excluded. The final sample resulted in 21 patients in RME group (mean age of 8.43 years) and 16 patients in SME group (mean age of 8.70 years). Based on the skewness and kurtosis statistics, the variables were judged to be normally distributed and paired t-test and student t-test were performed at significance level of 5%.RESULTS: Intermolar angle changed significantly due to treatment and RME showed greater buccal tipping than SME. RME showed significant changes in other four measurements due to treatment: maxilla moved forward and mandible showed backward rotation and, at transversal level both skeletal and dentoalveolar showed significant changes due to maxillary expansion. SME showed significant dentoalveolar changes due to maxillary expansion.CONCLUSIONS: Only intermolar angle showed significant difference between the two modalities of maxillary expansion with greater buccal tipping for RME. Also, RME produced skeletal maxillary expansion and SME did not. Both maxillary expansion modalities were efficient to promote transversal gain at dentoalveolar level. Sagittal and vertical measurements did not show differences between groups, but RME promoted a forward movement of the maxilla and backward rotation of the mandible.

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“…The greater expansion at dental level compared with the skeletal level has been previously reported 3 4 , 6 , 23 , 30 …”

Section: Discussionmentioning

confidence: 51%

Evaluation of the rapid and slow maxillary expansion using cone-beam computed tomography: a randomized clinical trial

Pereira¹,

Jacob

Locks

et al. 2017

Dental Press J. Orthod.

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“…54,55 The monocortical model, similar to previous bone-borne expansion models, produced significantly more parallel expansion than traditional tooth-borne expanders. 11,45,57,59 More parallel expansion is favorable for patients because it improves stability and increases the amount of expansion in the posterior region of the maxilla where expansion is often necessary and difficult to achieve. 11,56,58 However, while the monocortical model and previous bone-borne expansion models were better than tooth-borne expanders, they still produced a partial V-shaped expansion indicating that further parallel expansion was needed.…”

Section: Discussionmentioning

confidence: 99%

Effects of monocortical and bicortical mini-implant anchorage on bone-borne palatal expansion using finite element analysis

Lee

Moon

Hong

2017

American Journal of Orthodontics and Dentofacial Orthopedics

118

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Introduction Bone-borne palatal expansion relies on mini-implant stability for successful orthopedic expansion. The large magnitude of applied force experienced by mini-implants during bone-borne expansion may lead to high failure rates. Use of bicortical mini-implant anchorage rather than monocortical anchorage may improve mini-implant stability. The aim of this study was to analyze and compare the effects of bicortical and monocortical anchorage on stress distribution and displacement during bone-borne palatal expansion using finite element analysis (FEA). Methods Two skull models were constructed to represent expansion prior to and after midpalatal suture opening. Three clinical situations with varying mini-implant insertion depths were studied in each skull model: monocortical, 1mm bicortical, and 2.5mm bicortical. FEA simulations were performed for each clinical situation in both skull models. Von Mises stress distribution and transverse displacement was evaluated for all models. Results Peri-implant stress was greater in the monocortical anchorage model compared to both bicortical anchorage models. In addition, transverse displacement was greater and more parallel in the coronal plane for both bicortical models compared to the monocortical model. Minimal differences were observed between the 1mm bicortical and 2.5mm bicortical models for both peri-implant stress and transverse displacement. Conclusions Bicortical mini-implant anchorage results in improved mini-implant stability, decreased mini-implant deformation and fracture, more parallel expansion in the coronal plane, and increased expansion during bone-borne palatal expansion. However, the depth of bicortical mini-implant anchorage was not significant.

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“…A recent study has shown the overall results of RPE treatment produce 49% dental tipping, 38% skeletal expansion, and 13% alveolar tipping 9. Anatomical factors such as the large surface area of sutures surrounding the maxillary complex limit the sutural opening by creating more resistance to expansion superior and posteriorly 10.…”

Section: Introductionmentioning

confidence: 99%

“…It was reported that RPE therapy produces a significant increase in nasal width of 37.2% and a decrease in maxillary sinus width 9. Garib et al12 specified the increase in nasal floor width as equal to one-third of the expander's jack screw opening.…”

Section: Introductionmentioning

confidence: 99%

Does hyrax expansion therapy affect maxillary sinus volume? A cone-beam computed tomography report

et al. 2012

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PurposeThe aim of this study was to investigate the initial effects of maxillary expansion therapy with Hyrax appliance and to evaluate the related changes in maxillary sinus volume.Materials and MethodsThirty patients (20 females, 10 males; 13.8 years) requiring maxillary expansion therapy, as part of their comprehensive orthodontic treatment, were examined. Each patient had cone-beam computed tomography (CBCT) images taken before (T1) and after (T2) maxillary expansion therapy with a banded Hyrax appliance. Multiplanar slices were used to measure linear dimensions and palatal vault angle. Volumetric analysis was used to measure maxillary sinus volumes. Student t tests were used to compare the pre- and post-treatment measurements. Additionally, differences between two age groups were compared with Mann-Whitney U test. The level of significance was set at p=0.05.ResultsComparison of pre-treatment to post-treatment variables revealed significant changes in the transverse dimension related to both maxillary skeletal and dental structures and palatal vault angle, resulting in a widened palatal vault (p<0.05). Hard palate showed no significant movement in the vertical and anteroposterior planes. Nasal cavity width increased on a mean value of 0.93mm(SD=0.23, p<0.05). Maxillary sinus volume remained virtually stable. No significant age differences were observed in the sample.ConclusionHyrax expansion therapy did not have a significant impact on maxillary sinus volume.

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Editor's Summary, Q & A, Reviewer's Critique

Cited by 193 publications

References 18 publications

Evaluation of the rapid and slow maxillary expansion using cone-beam computed tomography: a randomized clinical trial

Evaluation of the rapid and slow maxillary expansion using cone-beam computed tomography: a randomized clinical trial

Effects of monocortical and bicortical mini-implant anchorage on bone-borne palatal expansion using finite element analysis

Does hyrax expansion therapy affect maxillary sinus volume? A cone-beam computed tomography report

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