0 pontifÍcia universidade catÓlica de minas gerais ... · em especial ao prof. dr. bernardo...
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DE MINAS GERAIS
Programa de Pós-graduação em Odontologia
EFEITOS DENTOESQUELÉTICOS DE 3 DISJUNTORES DIFERENTES EM PACIENTES FISSURADOS: UM ESTUDO CLÍNICO RANDOMIZADO
DANIEL SANTOS FONSECA FIGUEIREDO
Belo Horizonte
2011
Daniel Santos Fonseca Figueiredo
EFEITOS DENTOESQUELÉTICOS DE 3 DISJUNTORES DIFERENTES EM
PACIENTES FISSURADOS: UM ESTUDO CLÍNICO RANDOMIZADO
Dissertação apresentada ao Programa de Pós-graduação em Odontologia-Mestrado, da Pontifícia Universidade Católica de Minas Gerais, como parte dos requisitos para a obtenção do título de Mestre em Odontologia, Área de Concentração: Ortodontia.
Orientador: Prof. Dr. Ildeu Andrade Júnior Co-orientador: Prof. Dr. Dauro Douglas Oliveira
Belo Horizonte
2011
FICHA CATALOGRÁFICA Elaborada pela Biblioteca da Pontifícia Universidade Católica de Minas Gerais
Figueiredo, Daniel Santos Fonseca V164u Efeitos dentoesqueléticos de 3 disjuntores diferentes em pacientes fissurados:
um estudo clínico randomizado / Daniel Santos Fonseca Figueiredo. Belo Horizonte, 2011.
40f. : il. Orientador: Ildeu Andrade Júnior Coorientador: Dauro Douglas Oliveira Dissertação (Mestrado) – Pontifícia Universidade Católica de Minas Gerais.
Programa de Pós-Graduação em Odontologia. 1. Técnicas de expansão palatina. 2. Fenda palatina. 3. Tomografia
computadorizada de feixe cônico. I. Andrade Júnior, Ildeu. II. Oliveira, Dauro Douglas. III. Pontifícia Universidade Católica de Minas Gerais. Programa de Pós-Graduação em Odontologia. IV. Título.
CDU: 616.314-089.23
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FOLHA DE APROVAÇÃO
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Aos meus queridos pais, por sutilmente me mostrarem qual caminho seguir
Com amor,
Dedico este trabalho
1 -
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AGRADECIMENTOS
Ao Prof. Dr. Ildeu Andrade Jr, pela orientação neste projeto. Estou muito grato
pela grande contribuição não somente em relação a este trabalho, mas também na
minha formação como ortodontista.
Ao Prof. Dr. Dauro Douglas Oliveira, pela grande confiança em mim
depositada desde o início do curso. Esteja certo que estarei eternamente grato pelas
oportunidades concedidas. Agradeço-te por ser meu exemplo de profissional a
seguir.
Ao Prof. Juan Martin Palomo, por abrir as portas da Case Western Reserve
University e me orientar na análise das imagens. A experiência vivida na CWRU foi
enriquecedora não somente para esta pesquisa, mas também para minha formação
pessoal. Apesar do trabalho incessante, já me lembro com saudades dos dias
vividos em Cleveland.
Agradeço aos meus queridos professores: Armando Lima, José Eymard,
Bernardo Souki, Flávio Almeida, Ênio Mazzieiro, Tarcísio Junqueira, Júlio Brant,
Hélio Brito, Heloísio Leite, Dauro Oliveira, Ildeu Andrade e José Maurício pelos
valiosos ensinamentos. Vosso exemplo de dedicação me fez descobrir o amor pela
profissão.
Em especial ao Prof. Dr. Bernardo Souki, pela confiança depositada na
realização de atividades extracurriculares. Esteja certo que é um grande exemplo de
professor e de profissional.
Agradeço aos meus professores na Universidade Federal de Minas Gerais:
Alexandre Drummond, Elizabeth Lages, Henrique Pretti, Leonardo Foresti, José
Ferreira Rocha, que mesmo sem saber, foram minha inspiração inicial para o
ingresso na Ortodontia.
Ao Dr. Camilo Aquino Melgaço pelos ensinamentos e confiança. Seu exemplo
de vida e determinação é um grande estímulo para os meus ideais.
Ao Prof Dr. Martinho Campolina Horta, por sua dedicação na coordenação do
mestrado e pela valiosa ajuda na parte estatística deste trabalho.
Aos professores e alunos da Case Western Reserve University, bem como
aos Prof. Lincoln Nojima e Matilde Nojima, pela hospitalidade e troca de
experiências.
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Às Profas. Luciana Fonseca e Fernanda Fonseca pela ajuda na aquisição das
tomografias.
Aos pacientes e funcionários, especialmente ao Diego, Alcides e Lorraine. O
comprometimento de vocês foi fundamental para o sucesso de minha formação.
À colega Flávia Bartolomeo, pela ajuda na montagem da amostra e por
sempre se mostrar tão solicita.
Ao colega Alcides Santos Souza, pela disponibilidade e confecção dos
aparelhos utilizados nesta pesquisa
À FAPEMIG, pela bolsa concedida, por meio da qual foi possível minha
permanência e conclusão deste tão almejado curso.
Aos meus queridos amigos de turma Petrus Lopes, Alessandra Trindade,
Fernanda Aroeira e Raquel Castro. Tenho certeza que estes foram apenas os
primeiros anos de uma grande amizade. Obrigado pelo companheirismo e pelos
momentos de descontração.
Em especial ao Petrus Lopes, pela parceria e pelas valiosas caronas. E a seu
tio Adauto Lopes, por abrir as portas de seu consultório e passar um pouco de sua
grande experiência profissional.
Aos colegas das turmas X e XII, em especial a Larissa Salgado, Cybelle
Pereira e Lucas Cardinal pela ótima convivência fazendo com que o nosso dia-a-dia
fosse bem mais agradável.
À Izabella, meu amor, por se tornar esta pessoa tão especial em minha vida.
Obrigado por ser sempre tão carinhosa e paciente.
Aos meus amados pais, por abrirem mão dos seus próprios sonhos e anseios
para que esta etapa fosse cumprida. Sou eternamente grato a vocês.
Às minhas irmãs, Renata e Flávia, pelo apoio e cumplicidade.
Aos meus amigos do colégio e da faculdade, por me fazer lembrar cada dia o
valor de uma verdadeira amizade.
A Deus, por permitir que tudo isso seja possível.
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Eu tenho uma espécie de dever, de dever de sonhar de sonhar sempre, pois sendo mais do que um espectador de mim mesmo, eu tenho que ter o melhor espetáculo que posso. E assim construo a ouro e sedas, em salas supostas, invento palcos, cenário para viver o meu sonho entre luzes brandas e músicas invisíveis. (Fernando Pessoa)
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RESUMO
Objetivo: Avaliar e comparar, em pacientes com fissura labiopalatina (FLP), as
mudanças dentárias e esqueléticas da maxila, nos planos transversal, vertical e
sagital com 3 disjuntores diferentes. Metodologia: Trinta pacientes portadores de
FLP unilateral com deficiência maxilar transversa foram aleatoriamente divididos em
3 grupos: (I) “Haas Borboleta”; (II) Mini-Hyrax invertido e (III) Hyrax. Tomografias
computadorizadas de feixe cônico (TCFC) foram obtidas em dois tempos, antes do
tratamento e após 3 meses de contenção, a fim de avaliar as mudanças dentárias e
esqueléticas. O teste t pareado foi utilizado para avaliar as mudanças em cada
grupo. O teste one-way ANOVA, seguido pelo Bonferroni’s post hoc, foi utilizado
para identificar diferenças significativas entre os grupos. Resultados: Houve um
deslocamento anterior significativo da maxila nos pacientes com Haas Borboleta
(p<0,05), enquanto nos pacientes com Hyrax a maxila se deslocou mais no sentido
inferior (p<0,05). Observou-se uma maior expansão transversal das coroas em
relação à expansão nos ápices, bem como em relação à expansão esquelética nos 3
grupos. Os resultados mostraram que os 3 aparelhos estudados apresentaram
expansão similar na região anterior da maxila, enquanto o Haas Borboleta
demonstrou menor expansão na região posterior. Os segmentos maxilares
expandiram de maneira simétrica (p>0,05) e não houve diferença na inclinação
dentária entre lado fissurado e não fissurado (p>0.05). Conclusões: As maiores
mudanças foram observadas no plano transversal. Houve maior expansão ao nível
das coroas em relação às regiões basais e uma expansão simétrica entre os lados
fissurado e não fissurado. Os 3 aparelhos estudados podem ser usados de forma
eficaz em pacientes portadores de FLP. Entretanto, o expansor “Haas Borboleta” foi
o que apresentou menor expansão na região posterior, o que sugere que o Haas
Borboleta deva ser o mais indicado para os casos em que a atresia se restringe à
região anterior e a expansão posterior não é desejável.
Palavras-chave : Técnica de expansão palatina. Fissura palatina. Tomografia
computadorizada de feixe cônico.
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ABSTRACT
Objective: Evaluate and compare, by using cone-beam computed tomography
(CBCT), the transverse, vertical, and anteroposterior skeletal and dental changes of
the maxilla with three different expanders used in cleft patients. Methods: Thirty
unilateral CLP patients with transverse maxillary deficiency were randomly divided
into 3 groups: (I) FT expander; (II) iMini and (III) Hyrax-type expander. The CBCT
images were taken before treatment and after 3 months of retention. Paired t test
was used to evaluate the changes in each group. The one-way ANOVA followed by
Bonferroni’s post hoc test was used to identify significant differences between
groups. Results: The subjects in the FT group had a significantly forward
displacement of the maxilla (p <0.05), while the Hyrax group showed a downward
displacement (p <0.05). All transverse linear measurements had a significant
increase in the 3 groups (p <0.05). Dental crown expansion was greater than apical
and skeletal expansion with all appliances. There was a similar anterior expansion
among the three groups, while the FT group showed less expansion in the posterior
region. The cleft side and the noncleft side expanded symmetrically (p> 0.05) and
there was no difference in dental tipping between these sides (p>0.05).
Conclusions: The greatest changes were observed in the transverse plane of space
in all groups. There was greater expansion at crowns level in relation to the basal
ones and a simmetrical expansion between cleft and noncleft sides. All expanders
were effective to correct the transverse maxillary deficiency. However, the FT
appliance showed the lesser expansion in the posterior region, which suggests that
the FT expander might be the best choice in cleft patients with transverse maxillary
deficiency only at the anterior region.
Key-words: Palatal expansion technique. Cleft palate. Cone-beam computed
tomography.
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SUMÁRIO
1 INTRODUÇÃO ...................................................................................................10
2 OBJETIVOS ........................................ ...............................................................12
2.1 Objetivos específicos .......................... ...........................................................12
ARTIGO ....................................................................................................................13
CONSIDERAÇÕES FINAIS ............................... .......................................................36
REFERÊNCIAS.........................................................................................................38
ANEXO A............................................ ......................................................................40
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1 INTRODUÇÃO
A expansão rápida da maxila (ERM) é um procedimento amplamente
empregado na Ortodontia. Em pacientes fissurados esta terapia é rotineiramente
utilizada no reposicionamento dos segmentos maxilares (TOWNEND, 1980;
CAPELOZZA et al. 1994), que muitas vezes encontram-se transversalmente
constritos devido às sequelas das cirurgias reparadoras primárias. Estas cirurgias
geram um tecido cicatricial que inibe o crescimento e desenvolvimento maxilar no
sentido transversal e sagital (SUBTELNY, 1957; SHETYE, EVANS, 2006).
Entretanto, a diminuição da dimensão transversa é mais expressiva na região
anterior do arco (TOWNEND, 1980; CAPELOZZA et al. 1994), o que freqüentemente
cria um desafio clínico ao ortodontista.
Diversos aparelhos disjuntores foram preconizados na literatura com o
objetivo de corrigir a atresia maxilar em pacientes fissurados, como por exemplo o
do tipo Hyrax (SILVA FILHO et al. 2009) e o expansor “em leque” (TOWNEND,
1980). Os disjuntores convencionais, como os do tipo Hyrax ou Haas, promovem
expansão tanto na região posterior quanto na anterior do arco dentário (GARIB et
al., 2005; WEISSHEIMER et al.,2011). Este padrão de abertura muitas vezes é
indesejável no tratamento de pacientes com fissura labiopalatina (FLP), pois o limite
da disjunção posterior pode ser alcançado antes que a expansão anterior almejada
seja obtida.
Dessa forma, com o intuito de gerar maior expansão na região intercaninos,
foi desenvolvido o expansor “em leque” (TOWNEND, 1980; LEVRINI, FILLIPPI,
1999; COZZA et al., 2003; DORUK et al., 2004) que no Brasil é conhecido como
“Haas Borboleta” (SILVA FILHO et al., 2002; DRUMMOND et al., 2008). Uma
dobradiça foi adicionada na porção posterior do aparelho com a finalidade de
restringir a expansão excessiva na região intermolares. Outra opção de disjuntor é o
Mini-Hyrax invertido, que consiste em um parafuso de tamanho reduzido localizado
na região de caninos. Devido a sua localização, esperar-se-ia maior expansão na
área de pré-maxila em relação à região de molares, quando comparado aos
disjuntores convencionais. Além disso, por apresentar menores dimensões e
dispensar a parte acrílica, este aparelho parece ser uma alternativa mais confortável
e higiênica para o paciente.
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Apesar da diversidade de disjuntores descritos para portadores de FLP, existe
uma carência de trabalhos científicos que comprovem efeitos dentoesqueléticos da
ERM nestes pacientes em 3 dimensões. Sabe-se, no entanto, que os efeitos
biomecânicos da disjunção em pacientes portadores de FLP parecem ser diferentes
daqueles que não possuem esta deformidade craniofacial (PAN et al., 2007). Este
fenômeno ocorre principalmente devido à ruptura da integridade dos tecidos que
compõe o palato e o osso alveolar, o que gera uma estrutura anatômica
diferenciada. Especula-se, inclusive, que devido a esta peculiaridade anatômica, há
expansão assimétrica entre o lado fissurado e o lado não fissurado (SUBTELNY;
BRODIE, 1954; ISAACSON, 1964; PAN et al., 2007). Entretanto, não há um
consenso na literatura e novos estudos se fazem necessários para a confirmação
desta hipótese.
A literatura também carece de estudos clínicos randomizados para avaliar os
efeitos dentoesqueléticos dos expansores nos pacientes fissurados, sejam eles “em
leque” ou convencionais. Essa carência é ainda maior se considerarmos avaliações
tridimensionais utilizando tomografia computadorizada de feixe cônico (TCFC).
Conhecendo melhor os efeitos de cada expansor nos pacientes fissurados, o
ortodontista poderia indicar com mais segurança qual seria o aparelho mais
adequado para cada caso. Dessa forma, o objetivo deste trabalho foi avaliar e
comparar, por meio de TCFC, os efeitos dentoesqueléticos da ERM em pacientes
com FLP unilateral realizada com os disjuntores “Haas Borboleta”, Mini-Hyrax
invertido e Hyrax. Além disso, avaliar-se-á a simetria da expansão obtida com esses
aparelhos.
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2 OBJETIVOS
Avaliar e comparar, por meio de TCFC, as mudanças dentoesqueléticas
transversais, verticais e sagitais da maxila em pacientes com FLP utilizando os
disjuntores: “Haas Borboleta”, Mini-Hyrax Invertido e Hyrax convencional.
2.1 Objetivos específicos
a) Avaliar e comparar as mudanças criadas pelos 3 expansores nas seguintes
medidas dentoesqueléticas:
− SNA (posicionamento ântero-posterior da maxila)
− HL-ANS (posicionamento vertical da maxila)
− Distância Intercoroa, Distância Interalveolar, Distância Interápice e Largura da
Cavidade Nasal, tanto na região anterior quanto na posterior.
b) Avaliar e comparar a simetria da expansão entre lado fissurado e não
fissurado, bem como a inclinação dentária em cada um dos segmentos
maxilares.
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ARTIGO
Formatado para envio ao American Journal of Orthodontics and Dentofacial Orthopedics
Dentoskeletal effects of 3 different maxillary expa nders in cleft
patients: A randomized clinical trial
a Daniel Santos Fonseca Figueiredo b Flávia Uchôa Costa Bartolomeu b Lucas Cardinal da Silva c Juan Martin Palomo d Martinho Campolina Rebello Horta e Ildeu Andrade Jr f Dauro Douglas Oliveira
a Orthodontic resident, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Brazil. b Former Orthodontic residents, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Brazil. c Associate professor and program director, Department of Orthodontics, and Director of the Craniofacial Imaging Center, School of Dental Medicine, Case Western Reserve University, Cleveland, Ohio. d Associate professor and Dean of graduate studies, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Brazil. e Associate professor of Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Brazil. f Associate professor and program director of Orthodontics, Pontifical Catholic University of Minas Gerais, Belo Horizonte, Brazil. Corresponding author: Daniel Santos Fonseca Figueiredo Av. Dom José Gaspar, 500, Belo Horizonte-MG, Brazil. CEP: 30535-610 Phone: 55-31-8791-9080 E-mail: [email protected]
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ABSTRACT
Introduction: The purposes of this study were to evaluate and compare, by using
cone-beam computed tomography (CBCT), the transverse, vertical, and
anteroposterior skeletal and dental changes of the maxilla with three different
expanders used in cleft patients: the “Fan-type” expander (FT), the inverted Mini
Hyrax (iMini) and the conventional Hyrax-type. Methods: Thirty unilateral cleft lip and
palate patients with transverse maxillary deficiency were randomly divided into 3
groups: (I) FT expander; (II) iMini; and (III) Hyrax-type expander. The CBCT images
were taken before treatment and after 3 months of retention. Paired t test was used
to evaluate the changes in each group. The one-way ANOVA followed by
Bonferroni’s post hoc test was used to identify significant differences between
groups. Results: The subjects in the FT group had significantly forward displacement
of the maxilla (p <0.05), while the Hyrax group showed a downward displacement (p
<0.05). All transverse linear measurements had a significant increase in the 3 groups
(p <0.05). Dental crown expansion was greater than apical expansion and skeletal
expansion with all appliances. There was a similar anterior expansion among the
three groups, while the FT group showed less expansion in the posterior region. The
cleft side and the noncleft side expanded symmetrically (p> 0.05) and there was no
difference in dental tipping between these sides (p>0.05). Conclusions: The
greatest changes were observed in the transverse plane of space in all groups.
There was greater expansion at crowns level in relation to the basal ones and a
simmetrical expansion between cleft and noncleft sides. All expanders were effective
to correct the transverse maxillary deficiency. However, the FT appliance showed the
lesser expansion in the posterior region, which suggests that the FT expander might
be the best choice in cleft patients with transverse maxillary deficiency only at the
anterior region.
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INTRODUCTION
Cleft lip and palate (CLP) is one of the most common birth defects that affect
the craniofacial complex. After the primary repair surgeries, the maxillary segments
are brought together by the restored lip function and scar tissue, thus exacerbating
the maxillary constriction, particularly in the anterior region.1,2 Rapid maxillary
expansion (RME) is a commonly used therapy to correct this transverse deficiency.
Different RME appliances such as the Hyrax3 and the “Fan-type” expander (FT)4,5
have been used to correct the transverse deficiency in cleft patients. Often, the goal
has been to increase the anterior maxillary expansion, and at the same time, to
restraint the posterior one, since in most CLP patients there is a greater anterior than
posterior maxillary constriction.
However, the biomechanical effects of RME in CLP patients seem to be
different from those register for patients without this craniofacial deformity.6 There is
a rupture in the integrity of the alveolar bone and palatal tissues that leads to a
different anatomical structure in these patients. Moreover, it has been speculated that
this disharmony generates an asymmetrical expansion between the cleft and the
noncleft maxillary segments.6-8 Nevertheless, there is no consensus in the literature
and further studies are necessary to confirm this hypothesis.
There is also a lack of randomized clinical studies using cone beam computed
tomography (CBCT) to evaluate both skeletal and dental changes caused by different
RME appliances in cleft patients. Several investigations have analyzed the effects of
RME through 2-dimensional cephalometric radiographs and dental casts.7-9 However,
these diagnostic tools provide limited information, since only 2-dimensional data can
be processed from a 3-dimensional (3D) subject. Three-dimensional volumetric
imaging, such as CBCT, allows the investigator to 3-dimensionally measure
treatment-related structural changes with minimal image distortion and relatively low
radiation dosages compared with conventional computed tomography.10,11
The purpose of this study was to evaluate and compare by CBTC the
dentoskeletal changes of the maxilla after RME performed with 3 different expanders.
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MATERIAL AND METHODS
This study was approved by the Ethical Committee of the Pontifical Catholic
University of Minas Gerais (PUC Minas) in Brazil, and an informed consent was
obtained from all parents. The study sample comprised 30 unilateral cleft lip and
palate (UCLP) children (20 boys, 10 girls) who sought orthodontic treatment at the
Center of Craniofacial Anomalies (Centrare), Department of Orthodontics. The
selection criteria were: presence of UCLP, need for maxillary expansion treatment
and age between 8 and 15 years. The exclusion criteria included: absence of
maxillary first molars, periodontal disease, previous orthodontic treatment and
presence of any syndrome. The cervical vertebra maturation was assessed and
showed all patients before or during the pubertal growth spurt (stages of cervical
maturation varies between CS1 to CS4).12
The sample was randomly allocated into 3 groups with 10 patients each: (1)
fan-type maxillary expander (FT); (2) inverted Mini-Hyrax (iMini); and (3) Hyrax
expander. Sex and age distributions are shown in Table I for all groups. The FT
expander is a tooth tissue-borne appliance with a jackscrew and a posterior hinge
(Morelli, Sorocaba, São Paulo, Brazil) located at the molar region (Fig 1A). The iMini
is a tooth-borne appliance (Dynaflex, Sait Ann, Missouri) designed with a mini screw
positioned at the anterior region (Fig 1B). The Hyrax is a tooth-borne appliance with a
jackscrew (Leone, Florence, Italy) located in the deciduous molars or bicuspids
region (Fig 1C). All expanders were made by the same technician, and the bands
were placed only on the maxillary first molars with wire extensions bonded to the
adjacent teeth.
A pretreatment CBCT image (T1) was taken as part of the initial orthodontic
records of all patients. The expansion regimen was 2 turns per day until the required
expansion was achieved or until posterior dental crossbite overcorrection was
achieved. The appliance was kept in place as a passive retainer for an average of 3
months (Table I). After the retention period, the expander was removed and a
postexpansion CBCT image (T2) was immediately taken. On the same day, a
transpalatal bar with anterior extensions was inserted as a retainer. The T2 CBCT
was justified because of its valuable importance in bone graft planning. None of the
patients received any brackets or wires in the maxillary arch until the second CBCT
image was taken.
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All scans were obtained by the same technician with an I-CAT machine
(Imaging Sciences International, Hatfield, Pa). All CBTC images were oriented and
standardized by using Dolphin Imaging (version 11.5, Dolphin Imaging &
Management Solutions, Chatsworth, Calif). Each patient head was oriented in 3
planes of space for frontal, right lateral and top (facing down) views. The head was
positioned, in frontal view, with the right and left frontozygomatic sutures parallel to
the floor. In the right lateral view, the Frankfort horizontal line was placed parallel to
the floor. In the top view (facing down), the line connecting cristi galli to the landmark
Basion was aligned positioning the mid-sagittal plane.
To examine the effects of RME, the measurements were evaluated at T1 and
T2 in three planes of space: anteroposterior (AP), vertical and transversal. The AP
plane was assessed in lateral cephalograms obtained through CBCT by the SNA
measurement (Fig 2, A and B). The vertical plane was verified using CBCT sagittal
slices, measuring the lesser distance between the Frankfort Horizontal Line and ANS
(HL-ANS) - (Fig 3). The transverse dimension of the maxilla was measured with axial
and coronal scans. The transverse posterior maxillary measurements were taken at
the level of the first permanent molars. The transverse anterior measurements were
taken at the level of the most anterior appliance-supporting teeth. First premolars
were the most anterior teeth when the appliance extension could not achieve to
canines due to the narrowness of the anterior part of the maxilla. When roots were
used as reference, the palatal ones were chosen in molars and premolars. The
following parameters were used to quantify the amount of transversal expansion.
1. Dental crown width (DCW): transverse 3D width at coronal slices between the
most prominent lingual area of right and left posterior (Pt-DCW) and anterior (At-
DCW) teeth (Fig 4 A).
2. Maxillary basal width (MBW): the first maxillary right molar was found at the axial
slice. A landmark was placed in the center of the palatal root canal, at the level of
root separation. In the same slice, another landmark was placed in the root canal
of the most anterior appliance-supporting teeth. The same procedure was done in
the left side. A 3D line between the two landmarks in the posterior teeth
determined the posterior MBW (Pt-MBW). A second 3D line connecting the
landmarks in anterior teeth determined the anterior MBW (At-MBW) - (Fig 4 B).
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3. Dental apexes width (DAW): transverse 3D width at coronal section between
posterior teeth apexes (Pt-DAW) and between anterior teeth apexes (At-DAW) -
(Fig 4 A).
4. Nasal cavity width (NCW): To measure the posterior NCW (Pt-NCW), the palatal
root apex of the first maxillary right molar was localized at the coronal section. At
the same slice a landmark was placed on the right lateral wall at the widest portion
of the nasal cavity. Using a line parallel to the floor passing through the first
landmark, a second landmark was placed on the left lateral wall of the nasal
cavity. The Pt-NCW was the distance between these two points. The same was
done for the nasal width at the anterior region (At-NCW), using the right anterior
tooth root apex as reference (Fig 4 A).
5. Dental tipping (Tip): At coronal section, two lines were utilized to calculate the
tipping angle. The first one was perpendicular to the floor passing through the root
apex. The second one was designed passing through the palatal cusp tip and the
root apex. Dental tipping was obtained at the right and left sides of the posterior
(Pt-Tip) and anterior (At-Tip) teeth (Fig 4 C).
To evaluate what maxillary segment expanded more, the same landmarks
described for the MBW measurement were used. A mid-sagittal line connecting cristi
galli to the landmark Basion was defined as a reference line. At the axial slice, the
lesser distance from this mid-sagittal line to the each one of the four landmarks MBW
was measured (Fig 4 D). For this parameter, the patients were grouped according to
the cleft side.
Statistical Analysis
All measurements were made by the same operator (D.F) blinded to group
status. To test the intraexaminer reproducibility, 18 random images were remeasured
by the same examiner, a minimum of a week later, and compared to the original
measurements. Intraexaminer reliability values were determined with the intraclass
correlation coefficient. Descriptive statistics including means and standard deviations
were calculated for the measurements. The paired t test was used to evaluate
whether the changes from T1 to T2 were significantly different in each group. The
one-way ANOVA followed by Bonferroni’s post hoc test for paired comparisons was
used to evaluate differences in the changes of each measurement between the three
appliances. The data obtained from all measurements were processed with
GraphPad Prism (version 5.01, GraphPad Software, San Diego, Calif). The level of
19
significance for all statistical tests was predetermined at 5%. The intraexaminer
reproducibility test varied between 0.98 and 0.99, indicating high reproducibility
among measurements.
20
RESULTS
The FT group showed the greatest forward movement o f the maxilla
The FT group showed a statistically significant increase in SNA (0.83°), which
was greater than the iMini (-0.32°) and the Hyrax ( 0.12°) changes (Table II, III and IV,
respectively). However, when the results of all appliances were compared, the only
significant difference was found between the FT and the iMini group (Table V).
The Hyrax group presented the greatest downward mov ement of the maxilla
The Hyrax group showed a statistically significant increase in HL-ANS
(0.9mm), which was greater than the iMini (0.53mm) and the FT (0.04mm) changes
(Table IV, III and II, respectively). However, intergroup comparisons did not show
statistical difference in the vertical position of the maxilla (Table V).
There was a significant transverse maxillary expans ion in the 3 groups
All linear parameters observed in the transverse maxillary dimensions
demonstrated significant difference for the 3 appliances as shown in tables II, III and
IV. The 3 expanders showed a greater dental crown than apical expansion.
The FT group showed the lesser posterior expansion
The 3 groups demonstrated a similar anterior expansion (Table V). However,
intergroup comparison showed a lesser posterior maxillary expansion in the FT group
(Table V). When posterior and anterior expansions were compared in each group,
the FT expander revealed a lesser increase in posterior dimensions than anterior
(Table VI). On the other hand, the posterior MBW and DAW expansion was greater
than anterior MBW and DAW in iMini and Hyrax groups (Table VI).
There was no significant difference in dental tippi ng between appliances
All three groups demonstrated a greater anterior than posterior dental tipping.
However, there were no statistically significant differences in anterior or posterior
dental tipping when the 3 appliances were compared (Table V).
There was no significant difference in the nasal ca vity dimensions between
groups
No significant differences were noted comparing the changes in nasal cavity
dimensions between groups (Table V). Comparison between anterior and posterior
nasal cavity expansion in each group also presented no significant difference (Table
VI).
Cleft and noncleft sides were symmetrically expande d and there was no
difference in dental tipping between them
21
There was no significant difference in the amount of expansion when the cleft
and noncleft sides were compared in each group (Table VII). When the 30 patients
were evaluated together, blinded to the group status, still no significant difference
was found between the cleft and noncleft sides (Table VII). There was also no
difference in dental tipping between cleft side and noncleft side (Table VIII).
22
DISCUSSION
Despite the different types of expanders designed for cleft patients, the Hyrax-
type is still one of the most widely used in the world. This fact can be explained by
the lack of randomized clinical trials comparing the effects of conventional and non-
conventional expansors in CLP patients. Knowledge of their dental and skeletal
effects in cleft patients would lead the orthodontist to a expansion therapy that it is
customized to the patient’s individual need. Thus, the aims of this study were to
evaluate and compare, by means of CBCT, the effects of three different RME
expanders in UCLP patients: fan-type, inverted Mini-Hyrax and Hyrax-type. This
study also addressed questions of clinical interest: would be the FT or iMini more
effective to achieve a greater anterior maxillary expansion than the conventional
Hyrax-type? Does the cleft and the noncleft sides expand symmetrically?
With regard to previous reports that used CBCT images of patients who
underwent RME,13-18 the present study had some important features: (1) it was
performed on growing cleft patients; (2) it was a prospective study; (3) the patients
were randomly divided between the groups and (4) the skeletal maturation was
assessed. All sample subjects received RME treatment before or during the pubertal
growth spurt (cervical maturation interval CS1 to CS4). It has been reported that
patients treated before and during pubertal peak exhibit more effective changes at
the skeletal level, than those treated after pubertal growth spurt.19 There was no
control group because of ethical concerns and the short treatment time.
RME treatment-related structural changes in CLP patients have only been
measured with 2-dimensional radiographs and dental casts.7-9 CBCT technology
allows clinicians to measure 3D distances between anatomical landmarks,
eliminating the drawbacks of traditional auxiliary examinations, thus ensuring more
reliable and accurate measurements.10,11
Anteroposterior changes
In the present study, the FT expander showed a statistically significant
increase in the SNA (0.83°), which is in agreement with previous reports using the
same appliance in cleft9 and noncleft patients20. This means that the fan type RME
have a buttressing effect on the skeletal structures behind the maxilla because of the
rotational opening.20,21 However, the change was small and might not be clinically
significant.
23
Vertical changes
It has been reported that the maxilla is often downward displaced by RME in
noncleft20,22-24 and even in cleft patients6,9. Our findings showed that only the Hyrax
group demonstrated statistically significant downward displacement of the maxilla
(HL-ANS increased 0.9mm). However, contrasting results from previous studies
showed that the FT appliance moved the maxilla downward.9,20 The reasons for this
discrepancy are unknown but may be due to a sample difference, since those studies
were performed on noncleft subjects20 or using both unilateral and bilateral CLP
sample9.
Transverse Changes
All linear parameters observed in the transverse dimension presented
significant changes for the 3 appliances (Tables II, III and IV). As in previous RME
studies15,17,18,23,25 our findings indicated that the greatest widening occurred in the
dentoalveolar area, and the widening effect of the device gradually decreased
throughout the upper structures in a triangular pattern, indicating that dental
overexpansion is necessary to gain the appropriate skeletal effect.
Comparing the three groups, there was a similar anterior expansion at all
levels (Table V). However, at the level of maxillary basal width (Pt-MBW), the FT
group revealed 2.3 and 3.8 times less posterior expansion than the iMini and Hyrax
groups, respectively (Table IX). These findings confirms clinical impressions of
previous reports3,4,26 indicating that the incorporation of a posterior hinge can be
useful in cases that posterior expansion is undesirable. Our results corroborates with
a previous study using a FT appliance in noncleft patients, which revealed a greater
expansion in the intercanine comparing to the intermolar width (Table VI).20 Our
study also observed that the restrictive effect of the hinge decreases toward up,
reaching the expansion ratio of nearly 1:1 at the nasal cavity (Table VI).
There was an expectation that the iMini would achieve a greater expansion in
the anterior maxilla because of the anterior location of the screw. The resultant force
would be located more distant from the center of resistance of each maxillary half,27
which would theoretically propitiate more expansion in anterior than posterior region.
However, our results pointed out to a greater posterior than anterior expansion in
furcation and apex levels for iMini and Hyrax groups, These findings can be
explained by less tipping in posterior appliance supporting teeth when compared to
the anterior dental tipping. The data also showed a greater posterior expansion by
24
screw activation in the Hyrax group (93%) when compared to the iMini (57.9%) and
FT group (33.8%). These findings can explain the lesser screw activation for the
Hyrax group. Taken all together, our results suggested that the Hyrax appliance
should be better indicated to cleft cases presenting anterior and also posterior
transverse discrepancy.
Meanwhile, all three groups demonstrated a greater anterior than posterior
dental inclination (Table V). This would be expected since the posterior supporting
teeth were banded and firmly attached to the appliance, whereas the anterior
supporting teeth were just connected by lingual wire extension. As the screw was
activated, the bands provided resistance to inclination, which probably lead to a
greater bodily buccal movement of the banded teeth compared to non banded.13
However, although there was no significant difference in anterior dental tipping
between the 3 appliances (Table V), there was a 1:4 ratio between apex and crown
expansion for the FT group and 1:2 for the iMini and Hyrax groups. This means that
for each 10 mm of expansion in the anterior intercrown width, there was 2.5mm of
expansion in interapex width using the FT expander. In the Hyrax and iMini groups,
for each 10 mm of expansion in intercrown width, there was 5mm of expansion in the
interapex width. Therefore, the FT group seems to show a greater buccal tipping in
the anterior appliance-supporting teeth than others expanders, which might be
clinically relevant.
Previous studies have shown an association between RME and various
degrees of increase in the nasal cavity dimension.17,22,23,25 Our data clearly showed
that all 3 groups demonstrated an increase at the posterior and anterior in nasal
cavity width (Tables II, III, IV). However, there was no significant difference when the
3 groups were compared (Table V), which is in contrast with the results of a previous
study that found a lesser increase in the nasal cavity of the FT group when compared
to the Hyrax group.20 However, in the present study the groups showed no difference
when compared probably due to the lesser opening of the screw in the Hyrax group.
Cleft side x noncleft side expansion
Due to an asymmetrical anatomy of the maxilla, some studies have evaluated
if the cleft and noncleft sides of the maxilla are symmetrically expanded.6-8 By using
frontal cephalometric laminography, a previous study reported a greater expansion
on the cleft side and a greater dental tipping on the noncleft one.7 Moreover, a 2D
implant study suggested that the response of the maxillary segments was
25
unpredictable in nature.8 Recently, a 3D finite element study, reported an
asymmetrical movement of the maxillary segments.6 However those studies have
used small7,8 and not homogeneous8 samples, as well as 2D cephalometric
radiographs7,8. CBTC allowed us to clearly visualize and quantify the lateral changes
of the basal bone of the maxilla in relation with a stable structure in cranial base. Our
results show that in all appliances groups there was a greater expansion on the cleft
side, but the differences were not statistically significant (Table VII). When all 30
patients were evaluated together, still there were no significant differences between
cleft and noncleft sides. Furthermore, there was no significant difference in dental
tipping in the cleft side when compared with the noncleft side (Table VIII).
Other considerations
The use of CBCT to evaluate the RME in cleft patients, as well comparing
different appliances, might be of great value, enhancing our possibilities and
knowledge in the treatment of cleft patients. We assessed the effects of RME after 3
months; therefore, long-term evaluation is necessary for a better understanding of
the differences between the appliances.
26
CONCLUSIONS
Based on this clinical trial that evaluated and compared the dentoskeletal
effects of 3 different expanders on UCLP subjects, the following conclusions can be
drawn:
• The fan-type expander and the Hyrax expander showed the greatest forward and
downward movement of the maxilla, respectively. However, these findings might
not be clinically significant.
• RME produced significant increases in all linear measurements of the maxillary
transverse dimension for the 3 groups, including nasal cavity. The expansion
pattern had a triangular shape, with smaller effects at the basal levels than at the
crown level.
• There was a lesser posterior expansion in the fan-type group at crown and
apexes level, proving the effectiveness of the posterior hinge.
• The cleft side and the noncleft side expanded symmetrically and there was no
difference in dental tipping between these sides.
• Our study suggests that the FT expander might be the best choice in cleft patients
with maxillary constriction restricts into anterior region and the posterior
expansion is undesirable.
Acknowledgement: the first author of this study was a recipient of a postgraduate
studies scholarship sponsored by FAPEMIG – Fundação de Amparo à Pesquisa do
Estado de Minas Gerais.
27
ILLUSTRATIONS
Fig 1. A, Fan-type expander; B, iMini; C, Hyrax.
Fig 2. Anteroposterior measurement; A, angle SNA; B, rendering change to better identification of A point.
28
Fig 3. Vertical measurement. Sagittal slice showing HL-ANS.
Fig 4. Transversal measurements. A, Coronal slice showing DCW, DAW and NCW. The same was done for the anterior appliance support teeth. B, Axial slice showing At-MBW and Pt-MBW. C, Coronal slice showing posterior tipping, the same was done for cleft and noncleft side, in posterior and anterior region. D, Measurements showing the lateral displacement between cleft and noncleft side.
29
TABLES
Table I. Distribution of age (years), gender, cleft-side, retention time (days) and appliance expansion (mm).
Age Gender Cleft-side Retention Time Group
Mean SD M F R L Mean SD
Appliance
Expansion
FT 11.3 2.4 7 3 4 6 90,4 1,7 9,1
iMini 10.5 1.8 6 4 2 8 90,8 1,9 9,7
Hyrax 10.4 2.4 7 3 3 7 92.7 23.7 5,0
Table II. Maxillary dimensions results of the comparison between T1 and T2 of FT appliance group.
T1 T2 Variables Mean SD Mean SD
Mean of differences (T2-T1) P- value
Anteroposterior SNA (°) 79.30 4.98 80.13 4.76 0.83 <0.05 Vertical HL-ANS (mm) 17.58 2.54 17.62 2.48 0.04 n.s. Transversal Maxillary posterior DCW (mm) 31.31 3.27 34.41 2.56 3.10 <0.05 MBW (mm) 37.32 2.51 39.33 1.91 2.01 <0.05 DAW (mm) 31.14 2.14 32.31 1.60 1.17 <0.05 NCW (mm) 29.50
2.74 30.92 3.05 1.42 <0.05
Dental Tip CS (°)
15.20 5.15 17.58 4.85 2.38 n.s. Dental Tip NS (°) 13.14 3.54 16.30 4.48 3.16 <0.05 Maxillary anterior DCW (mm) 19.79 2.39 26.19 4.31 6.40 <0.05 MBW (mm) 26.37 2.89 29.41 3.78 3.04 <0.05 DAW (mm) 26.56 3.39 28.19 3.63 1.63 <0.05 NCW (mm) 26.30 3.11 27.39 3.44 1.09 <0.05 Dental Tip CS (°)
-4.03 5.25 7.37 7.70 11.40 <0.05 Dental Tip NS (°) 0.88 7.65 11.17 8.20 10.29 <0.05 p-values were obtained by paired t test. n.s.= not significant. CS= cleft side. NS=noncleft side
30
Table III. Maxillary dimensions results of the comparison between T1 and T2 of iMini appliance group.
T1 T2
Variables Mean SD Mean SD Mean of Differences
(T2-T1) P- value
Anteroposterior SNA (°) 80.36 5.18 80.04 4.89 -0.32 n.s. Vertical HL-ANS (mm) 16.92 2.39 17.45 2.49 0.53 n.s. Transversal Maxillary posterior DCW (mm) 31.29 2.63 36.91 2.83 5.62 <0.05 MBW (mm) 36.92 2.56 41.81 3.27 4.89 <0.05 DAW (mm) 32.25 3.14 36.29 3.74 4.04 <0.05 NCW (mm) 29.03
3.64 3.64 31.00 3.91 1.97 <0.05
Dental Tip CS (°)
13.89 7.85 16.31 6.76 2.42 <0.05 Dental Tip NS (°) 9.92 5.86 13.80 7.16 3.88 <0.05 Maxillary anterior DCW (mm) 19.25 2.54 23.84 2.65 4.59 <0.05 MBW (mm) 26.13 2.87 28.98 3.15 2.85 <0.05 DAW (mm) 26.94 3.38 29.26 3.82 2.32 <0.05 NCW (mm) 26.41 4.49 28.01 4.40 1.60 <0.05 Dental Tip CS (°)
-8.30 10.28 -0.54 13.96 7.76 <0.05 Dental Tip NS (°) -0.75 7.12 5.81 10.30 6.56 <0.05 p-values were obtained by paired t test. n.s.= not significant. CS= cleft side. NS=noncleft side
Table IV. Maxillary dimensions results of the comparison between T1 and T2 of Hyrax appliance group
T1 T2
Variables Mean SD Mean SD Mean of differences
(T2-T1) P- value
Anteroposterior SNA (°) 82.25 4.88 82.37 4.72 0.12 n.s. Vertical HL-ANS (mm) 17.00 1.51 17.90 2.13 0.90 <0.05 Transversal Maxillary posterior DCW (mm) 29.91 2.32 34.58 2.53 4.67 <0.05 MBW (mm) 35.78 2.64 39.80 2.54 4.02 <0.05 DAW (mm) 29.96 3.55 33.42 2.90 3.46 <0.05 NCW (mm) 28.36
3.64 2.52 30.15 3.00 1.79 <0.05
Dental Tip CS (°)
13.36 4.36 14.57 4.57 1.21 n.s. Dental Tip NS (°) 11.91 4.08 14.26 4.64 2.35 n.s. Maxillary anterior DCW (mm) 19.29 3.44 24.09 4.45 4.80 <0.05 MBW (mm) 26.53 2,90 29.33 3.03 2.80 <0.05 DAW (mm) 26.88 3.09 29.46 3.63 2.58 <0.05 NCW (mm) 24.52 3.88 26.29 3.85 1.77 <0.05 Dental Tip CS (°)
-8.8 7.07 -1.38 11.10 7.42 <0.05 Dental Tip NS (°) 0.89 6.25 6.97 6.88 6.08 <0.05 p-values were obtained by paired t test. n.s.= not significant. CS= cleft side. NS=noncleft side
31
Table V. Comparisons between the changes of the three groups.
FT iMini Hyrax
T2-T1 T2-T1 T2-T1
Variables Mean SD
Mean SD
Mean SD P- Value
Anteroposterior SNA (°) 0.83 0.72 -0.32 1.08 0.12 1.13 <0.05 a / n.s.b,c
Vertical HL-ANS (mm) 0.04 0.56 0.53 0.83 0.90 0.95 n.s.a,b,c
Transversal Maxillary posterior DCW (mm) 3.10 1.52 5.62 1.95 4.67 1.27 <0.05 a / n.s.b,c
MBW (mm) 2.01 1.42 4.89 1.65 4.02 1.36 n.s.a,b,c
DAW (mm) 1.17 1.60 4.04 1.51 3.46 1.59 <0.05 a,b / n.s.c
NCW (mm) 1.42 0.93 1.97 0.79 1.79 0.83 n.s.a,b,c
Dental Tip CS (°)
2.38 4.43 2.42 3.26 1.21 1.81 n.s.a,b,c
Dental Tip NS (°) 3.16 3.39 3.88 3.76 2.35 3.50 n.s .a,b,c
Maxillary anterior DCW (mm) 6.40 3.36 4.59 1.59 4.80 1.66 n.s.a,b,c
MBW (mm) 3.04 2.26 2.85 1.27 2.80 1.55 n.s.a,b,c
DAW (mm) 1.63 0.77 2.32 0.79 2.58 1.60 n.s.a,b,c
NCW (mm) 1.09 0.78 1.60 1.56 1.77 0.72 n.s.a,b,c
Dental Tip CS (°)
11.40 6.99 7.76 6.99 7.42 5.82 n.s.a,b,c
Dental Tip NS (°) 10.29 4.63 6.56 5.78 6.08 3.95 n. s.a,b,c
p-values were obtained by one-way ANOVA (Bonferroni’s post hoc test). a FT versus iMini. b FT versus Hyrax. c iMini versus Hyrax. n.s.= not significant. CS= cleft side.
NS=noncleft side
Table VI. Comparison of the transversal changes (mm) between the anterior and posterior region for each appliance.
Region
Groups Variables Anterior Posterior P- Value
DCW 6.40 3.10 <0.05 FT MBW 3.04 2.01 n.s. DAW 1.63 1.17 n.s. NCW 1.09 1.42 n.s. iMini DCW 4.59 5.62 n.s. MBW 2.85 4.89 <0.05 DAW 2.32 4.04 <0.05 NCW 1.6 1.97 n.s. Hyrax DCW 4.80 4.67 n.s. MBW 2.80 4.02 <0.05 DAW 2.58 3.46 n.s. NCW 1.77 1.79 n.s. p-values were obtained by paired t test. n.s.= not significant
32
Table VII. Cleft side and relative alveolar expansion (mm).
CS expansion NS expansion Groups Region Mean SD Mean SD
Mean of differences (CS-NS) P
Maxillary posterior 1.25 1.23 0.76 0.70 0.49 n.s. FT (n=10)
Maxillary anterior 1.89 1.21 1.13 1.38 0.76 n.s. iMini(n=10) Maxillary posterior 2.69 0.95 2.23 1.13 0.46 n.s. Maxillary anterior 1.53 0.75 1.18 1.19 0.35 n.s. Hyrax (n=10) Maxillary posterior 2.24 1.83 1.81 1.09 0.43 n.s. Maxillary anterior 1.58 2.41 1.23 1.91 0.35 n.s. All goups (n=30) Maxillary posterior 2.06 1.47 1.60 1.14 0.46 n.s. Maxillary anterior 1.66 1.57 1.18 1.47 0.48 n.s. p-values were obtained by paired t test. n.s.= not significant. CS= cleft side. NS=noncleft side
Table VIII. Cleft side and relative dental tipping.
Dental Tip - CS Dental Tip - NS Groups Region Mean Mean P- Value
Maxillary posterior 2.38° 3.16° n.s. FT (n=10)
Maxillary anterior 11.40° 10.29° n.s. iMini (n=10) Maxillary posterior 2.42° 3.88° n.s. Maxillary anterior 7.76° 6.56° n.s. Hyrax (n=10) Maxillary posterior 1.21° 2.35° n.s. Maxillary anterior 7.42° 6.08° n.s. All goups (n=30) Maxillary posterior 2.00° 3.13° n. s. Maxillary anterior 8.86° 7.64° n.s. p-values were obtained by paired t test. n.s.= not significant. CS= cleft side. NS=noncleft side
Table IX. Transversal changes (T2-T1) by mean screw expansion for each appliance.
Change/mean screw expansion (%) Variables FT iMini Hyrax Maxillary posterior
DCW 33.8 57.9 93.0 MBW 21.9 50.4 80.1 DAW 12.8 41.6 68.9 NCW 15.5 20.3 35.7 Maxillary anterior DCW 69.9 47.3 95.6 MBW 33.2 29.4 55.8 DAW 17.8 23.9 51.4 NCW 11.9 16.5 35.3
33
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36
CONSIDERAÇÕES FINAIS
Esse trabalho é parte de uma linha de pesquisa iniciada em 2009 pelos
professores Dauro Oliveira e Ildeu Andrade Jr.
Desde a criação do Centro de Tratamento e Reabilitação de Anomalias e
Deformidades Craniofaciais (CENTRARE), o volume de atendimento de pacientes
fissurados no Mestrado em Ortodontia da PUC Minas aumentou significativamente.
Boa parte desses indivíduos necessitava de expansão rápida da maxila. Duas
dificuldades clínicas chamavam a atenção do Prof. Dauro Oliveira: (1) o disjuntor do
tipo Hyrax não atendia a demanda de se obter maior expansão na região anterior da
maxila; (2) o disjuntor do tipo borboleta era muito volumoso, o que dificultava
sobremaneira a higienização e comprometia ainda mais funções essenciais que já
são dificultadas nos pacientes fissurados, como por exemplo fala e deglutição.
Diante dessas dificuldades, o prof. Dauro buscou alternativas clínicas aos
disjuntores mencionados acima. Foi tentada a utilização do disjuntor Mini-Hyrax
devido ao seu tamanho reduzido. Esse aparelho foi utilizado no posicionamento
convencional e também de forma invertida. Diante da avaliação clínica subjetiva de
que os resultados estavam sendo bastante satisfatórios, o Prof. Dauro se reuniu com
o Prof. Ildeu para discutir tais resultados. Durante essa reunião, esses professores
decidiram avaliar os resultados dos diferentes tipos de disjuntores em pacientes
fissurados sob um olhar objetivo e científico. Assim, uma série de estudos, da qual o
presente trabalho faz parte, foi iniciada para melhor compreender os efeitos das
diversas opções de aparelhos para se realizar a disjunção palatina.
Este estudo foi realizado em parceria com o Departamento de Ortodontia da
Faculdade de Odontologia da Case Western Reserve University (CWRU), localizada
em Cleveland (Ohio, EUA). A análise das imagens tomográficas foi realizada pelo
autor do presente trabalho sob orientação do Professor Juan Martin Palomo, Diretor
do Departamento de Ortodontia e do Centro de Imagem da Universidade.
De acordo com as normas vigentes na PUC Minas esta dissertação gerou o
artigo “Dentoskeletal effects of 3 different maxillary expanders in cleft patients: A
randomized clinical trial”, que foi formatado para submissão à revista American
Journal of Orthodontics and Dentofacial Orthopedics.
37
A elaboração deste estudo partiu de um planejamento ideal, mas durante a
sua execução algumas limitações metodológicas se apresentaram aos
pesquisadores.
Considerando os estudos prévios que utilizaram TCFC para avaliar os efeitos
da ERM, este estudo utilizou uma amostra maior ou equivalente (GARIB et al., 2005;
GARRET et al., 2008; LIONE et al., 2008; BALLANTI et al., 2009; WEISSHEIMER et
al., 2011). Entretanto, pode-se considerar que uma amostra com número maior de
pacientes seria mais adequada. A dificuldade encontrada é conseguir um grande
número de pacientes, já que se trata de uma amostra rara e que ainda tem que
passar por critérios de seleção, como idade, tipo de fissura, dentre outros já citados
no artigo.
Uma comparação mais adequada entre os disjuntores poderia ser feita caso a
quantidade de ativações fosse a mesma em todos os grupos. Entretanto, esta
padronização é difícil de ser alcançada, uma vez que os próprios efeitos dos
disjuntores influenciaram o número final de ativações. Foi observado clinicamente
que o expansor Hyrax alcançava o limite posterior da expansão com um número
reduzido de ativações. Como se preocupou em não criar uma mordida cruzada por
vestibular, considerada de difícil correção, a expansão foi finalizada no limite da
sobrecorreção transversal posterior. Esta impressão clínica foi comprovada nas
mensurações tomográficas.
Idealmente seria necessário um grupo controle para comparação. Porém,
devido a limitações no aspecto ético, tal feito não foi possível.
Concluímos que apesar dessas limitações o trabalho foi capaz de responder
aos objetivos propostos. Esta reflexão final tem o objetivo de contribuir para estudos
futuros, uma vez que esta é uma linha de pesquisa em andamento.
38
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ANEXO A – CARTA DE APROVAÇÃO DO COMITÊ DE ÉTICA DA PUC MINAS