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. 2024 Mar 4;29(1):e2423195.
doi: 10.1590/2177-6709.29.1.e2423195.oar. eCollection 2024.

Effect of different palatal expanders with miniscrews in surgically assisted rapid palatal expansion: A non-linear finite element analysis

Osman Koç  1 , Nagihan Koç  2 , Helder Baldi Jacob  3
Affiliations

Effect of different palatal expanders with miniscrews in surgically assisted rapid palatal expansion: A non-linear finite element analysis

Osman Koç et al. Dental Press J Orthod. .

Abstract
in English, Portuguese

Introduction: Surgically assisted rapid palatal expansion (SARPE) has been the treatment of choice in subjects presenting skeletally mature sutures.

Objective: The purpose of this study was to analyze stress distribution and displacement of the craniofacial and dentoalveolar structures resulting from three types of palatal expanders with surgical assistance using a non-linear finite element analysis.

Material and methods: Three different palatal expanders were designed: Model-I (tooth-bone-borne type containing four miniscrews), Model-II (tooth-bone-borne type containing two miniscrews), and Model-III (bone-borne type containing four miniscrews). A Le Fort I osteotomy was performed, and a total of 5.0 mm palatal expansion was simulated. Nonlinear analysis (three theory) method (geometric nonlinear theory, nonlinear contact theory, and nonlinear material methods) was used to evaluate stress and displacement of several craniofacial and dentoalveolar structures.

Results: Regardless of the maxillary expander device type, surgically assisted rapid palatal expansion produces greater anterior maxillary expansion than posterior (ANS ranged from 2.675 mm to 3.444 mm, and PNS ranged from 0.522 mm to 1.721 mm); Model-I showed more parallel midpalatal suture opening pattern - PNS/ANS equal to 54%. In regards to ANS, Model-II (1.159 mm) and Model-III (1.000 mm) presented larger downward displacement than Model-I (0.343 mm). PNS displaced anteriorly more than ANS for all devices; Model-III presented the largest amount of forward displacement for PNS (1.147 mm) and ANS (1.064 mm). All three type of expanders showed similar dental displacement, and minimal craniofacial sutures separation. As expected, different maxillary expander designs produce different primary areas and levels of stresses (the bone-borne expander presented minimal stress at the teeth and the tooth-bone-borne expander with two miniscrews presented the highest).

Conclusions: Based on this finite element method/finite element analysis, the results showed that different maxillary expander designs produce different primary areas and levels of stresses, minimal displacement of the craniofacial sutures, and different skeletal V-shape expansion.

Introdução:: A expansão rápida da maxila assistida cirurgicamente (ERMAC) tem sido o tratamento de escolha em indivíduos que apresentam suturas esqueleticamente maduras.

Objetivo:: O objetivo deste estudo foi avaliar, utilizando uma análise não linear com elementos finitos, a distribuição de tensões e os deslocamentos das estruturas craniofaciais e dentoalveolares gerados por três tipos de expansores palatinos usados na ERMAC.

Material e Métodos:: Três tipos de expansores palatinos foram projetados: Modelo I (dento-osseossuportado com quatro mini-implantes), Modelo II (dento-osseossuportado com dois mini-implantes) e Modelo III (osseossuportado com quatro mini-implantes). Uma osteotomia Le Fort I foi realizada e foi simulada uma expansão palatina total de 5,0 mm. Um método de análise não linear (três teorias - teoria da não-linearidade geométrica, teoria do contato não linear e métodos para materiais não lineares) foi utilizado para avaliar a tensão e o deslocamento de diversas estruturas craniofaciais e dentoalveolares.

Resultados:: Independentemente do tipo de aparelho expansor palatino, a ERMAC produziu maior expansão anterior da maxila do que posterior (ENA variou de 2,675 mm a 3,444 mm e ENP variou de 0,522 mm a 1,721 mm); o Modelo I apresentou padrão de abertura mais paralela da sutura palatina mediana, com ENP/ENA igual a 54%. Com relação à ENA, o Modelo II (1,159 mm) e o Modelo III (1,000 mm) apresentaram maior deslocamento para baixo do que o Modelo I (0,343 mm). A ENP deslocou-se mais para anterior do que a ENA com todos os aparelhos; o Modelo III apresentou o maior deslocamento para anterior da ENP (1,147 mm) e da ENA (1,064 mm). Os três tipos de expansores apresentaram deslocamento dentário semelhante e separação mínima das suturas craniofaciais. Como esperado, diferentes designs de expansores palatinos produzem diferentes áreas primárias e níveis de tensões (o expansor osseossuportado apresentou tensão mínima nos dentes, e o expansor dento-osseossuportado com dois mini-implantes apresentou o maior).

Conclusões:: Com base nesse estudo de elementos finitos, os resultados mostraram que diferentes designs de expansores palatinos produzem diferentes áreas primárias e níveis de tensão, com deslocamento mínimo das suturas craniofaciais e diferentes expansões esqueléticas em forma de V.

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Conflict of interest statement

The authors report no commercial, proprietary or financial interest in the products or companies described in this article.

Figures

Figure 1:
Figure 1:. Three different palatal expander appliances design: Model-I is a tooth-bone-borne expander with four miniscrews placed 4 mm lateral to midpalatal suture (A), Model-II is a tooth-bone-borne with two miniscrews placed at the third rugae area (B), and Model-III is a bone-borne with four miniscrews placed 8 and 10 mm from the midpalatal suture (C). Screws were moved 2.5 mm in a transverse ( Z-axis ) direction ( 5 mm in total ).
Figure 2:
Figure 2:. Displacement of the landmarks due to SARPE after 5 mm activation of the expander apparatus. Occlusal view simulation of the Model-I (A), Model-II (B), and Model -III (C), and frontal view simulation of the Model-I (D), Model-II (E), and Model -III (F).
Figure 3:
Figure 3:. Stress distribution values for craniofacial structures including the miniscrew sites for Model-I expander type after 5 mm activation of the expander apparatus. (A) Sagittal view, (B) Coronal slice view showing the pterygomaxillary suture, (C) Axial view, and (D) Axo-posterior view. Highest stress area is presented in red.
Figure 4:
Figure 4:. Stress distribution values for craniofacial structures including the miniscrew sites for Model-II expander type after 5 mm activation of the expander apparatus. (A) Sagittal view, (B) Coronal slice view showing the pterygomaxillary suture, (C) Axial view, and (D) Axo-posterior view. Highest stress area is presented in red.
Figure 5:
Figure 5:. Stress distribution values for craniofacial structures including the miniscrew sites for Model-III expander type after 5 mm activation of the expander apparatus. (A) Sagittal view, (B) Coronal slice view showing the pterygomaxillary suture, (C) Axial view, and (D) Axo-posterior view. Highest stress area is presented in red.
Figure 6:
Figure 6:. Skewness mesh metrics spectrum.
See this image and copyright information in PMC

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