Relação da espessura do osso cortical da crista infrazigomática e buccal shelf em diferentes tipos de padrões faciais / Relationship of the cortical bone thickness of the infrazigomatic and buccal shelf crest in different types of facial patterns

Resumo A crista infrazigomática e buccal shelf possuem maior quantidade de osso corticalizado, que favorece a instalação de mini-implantes pela diminuição dos riscos de acidentes como também pelas maiores chances de estabilidade primária. Este trabalho tem como finalidade analisar a espessura óssea na região da crista infrazigomática e buccal shelf em diferentes tipos de padrões faciais por meio de tomografia computadorizada de feixe cônico, a fim de constatar a presença suficiente de osso corticalizado nessas regiões para inserção de mini- -implantes. A amostra de conveniência foi composta por 24 tomografias, divididas em três grupos: dolicofacial (G1), mesofacial (G2) e braquifacial (G3), as quais foram mensuradas no solfware ImplantViewer 3. O estudo envolveu duas variantes: padrão de crescimento vertical e espessura da cortical óssea na área da crista infrazigomática e da buccal shelf. 30% da amostra foi utilizada para realização do cálculo de reprodutibilidade e posteriormente a amostra completa foi submetida à análise de variância, seguido do teste de post-hoc Tukey HSD. Não houve interferência do padrão facial para a crista infrazigomática, entretanto, houve diferença estatística entre os grupos braquifaciais e dolicofaciais, como também entre os braquifaciais e mesofaciais no que diz respeito ao buccal shelf, nos quais os indivíduos braquifaciais mostraram maior espessura, seguido dos mesofaciais e dolicofaciais. Concluiu-se que os indivíduos pertencentes ao grupo braquifacial apresentaram maior espessura na região da buccal shelf quando comparados aos demais, e todos os grupos apresentaram espessura suficiente para segura instalação dos mini-implantes. (AU)

Abstract The infrazygomatic crest and buccal shelf have a greater amount of cortical bone, which favors the installation of mini-implants, reducing the risk of accidents as well as the greater chances of primary stability. This study aims to analyze bone thickness in the region of the infrazygomatic crest and buccal shelf in different types of facial patterns by means of conical beam computed tomography, in order to verify the presence of corticalized bone in these regions for insertion of mini-implants. The convenience sample consisted of 24 CT scans, divided into three groups: dolichofacial (G1), mesofacial (G2), and brachyfacial (G3), which were measured in the ImplantViewer 3 solfware. The study involved two variants: vertical growth and thickness of the cortical bone in the infrazygomatic ridge and buccal shelf area. 30% of the sample were used to perform the reproducibility calculation and afterwards the entire sample was submitted to analysis of variance, following Tukey HSD post-hoc test. There was no interference of the facial pattern for the infrazygomatic ridge, however, there was a statistical difference between the brachyphacal and dolicofacial groups, as well as between the brachyfacial and mesofacial groups with respect to buccal shelf, in which brachyfacial individuals showed greater thickness, followed by mesofacial ones and dolichofacials. It was concluded that individuals belonging to the brachyfacial group presented greater thickness in the buccal shelf region when compared to the others, and all groups presented sufficient thickness for the safe installation of the mini-implants. (AU)

Mini-implant assisted rapid palatal expansion (MARPE) effects on adult obstructive sleep apnea (OSA) and quality of life: a multi-center prospective controlled trial.

INTRODUCTION: Transverse maxillary deficiency is a high prevalent growth disorder within the adult population that may lead to serious health issues, such as detrimental malocclusions and higher risk of developing obstructive sleep apnea (OSA). Mini-implant assisted rapid palatal expansion (MARPE), as it expands the mid-face and augment the nasal and oral cavities dimensions, may reduce the airflow resistance and thus play an important role on OSA therapy in some patients. The main objective of the present trial is to assess MARPE effects on the sleep and quality of life of non-obese adult OSA patients with transverse maxillary deficiency. METHODS: A total of 32 participants were divided into intervention and control groups. They underwent physical evaluation, Epworth Sleepiness Scale (EES) and Quebec Sleep Questionnaire (QSQ), cone-beam computed tomography (CBCT) and home sleep testing (HST) for OSA before MARPE (T1) and 6 months after the intervention (T2). RESULTS: Questionnaires EES (daytime sleepiness) and QSQ (OSA-related quality of life) presented significant statistical differences between the groups. We also found clinical and statistical (p < 0.01) differences between the groups regarding the apnea/hypopnea index (AHI), as well as others HST parameters (mean oxygen saturation and snoring duration). CONCLUSION: In our sample, MARPE (without any auxiliary osteotomy) showed a good success rate (85%) and promoted important occlusal and respiratory benefits. We observed important daytime sleepiness and OSA-related quality of life improvement, as well as the AHI (65.3%), oxygen saturation and snoring duration.

Avaliação da relação da espessura da sínfise mandibular em diferentes padrões de crescimentos faciais ­ estudo com tomografia computadorizada de cone-beam / Evaluation of the relationship of mandibular symphysis thickness in different facial growth patterns ­ study with cone-beam computed tomography

Resumo Muitas são as estruturas anatômicas importantes que permeiam o tratamento ortodôntico, sendo uma delas a sínfise mandibular, estrutura na qual os incisivos inferiores estão posicionados. Tal estrutura se torna ainda mais importante pois é responsável pela estética do terço inferior da face e está diretamente relacionada com o crescimento vertical facial. Sabe- -se que para o sucesso da Ortodontia é necessário um planejamento prévio minucioso que deve ser traçado a partir de exames radiográficos detalhados, pois é diante deles que surgirão as possibilidades de tratamento. A presente pesquisa buscou mensurar a espessura da sínfise mandibular de 30 tomografias computadorizadas de pacientes dos três diferentes tipos faciais (hipodivergente, normodivergente e hiperdivergente) a fim de relacionar essa medida com o biótipo facial. Para a mensuração, foi utilizado o software ImplantViewer 3 e as tomografias foram avaliadas nos três terços do elemento dentário (apical, médio e cervical). Ao final, os dados foram comparados a partir de análise estatística. Observou-se com o estudo que não houve diferença significativa da espessura da sínfise mandibular entre os biótipos faciais, no entanto, quando se comparou os terços de um mesmo biótipo facial, percebeu-se que no biótipo hipodivergente há diferença significativa entre os terços, no biótipo normodivergente houve significância entre os terços apical e médio e apical e cervical, e no biótipo hiperdivergente, apenas os terços apical e médio apresentaram significância estatística (AU)

Abstract There are many important anatomical structures that permeate orthodontic treatment, one of which is the mandibular symphysis, a structure in which the lower incisors are positioned. This structure becomes even more important because it is responsible for the aesthetics of the lower third of the face and is directly related to vertical facial growth. It is known that for the success of Orthodontics it is necessary to have a thorough prior planning that must be drawn from detailed radiographic exams, because it is before them that the possibilities of treatment will arise. This research attempted to measure the thickness of the mandibular symphysis of 30 CT scans of patients with three different facial types (hypodivergent, normodivergent, and hyperdivergent) in order to relate this measurement to the facial biotype. ImplantViewer3 software was used for the measurement and the CT scans were evaluated in the three thirds of the dental element (apical, middle, and cervical). At the end, the data were compared based on statistical analysis. It was observed with the study that there was no significant difference in the thickness of the mandibular symphysis between the facial biotypes, however, when comparing the thirds of the same facial biotype, it was noticed that in the hypodivergent there is a significant difference, in the normodivergent biotype there was significance between the apical and middle and apical and cervical thirds, and in the hyperdivergent biotype, only the apical and medium presented statistical significance.(AU)

Miniscrew-assisted rapid palatal expansion (MARPE): how to achieve greater stability. In vitro study.

OBJECTIVE: Assess the influence of mono- and bicortical anchorage and diameter of mini-implants (MIs) on the primary stability of these devices. METHODS: 60 self-drilling MIs were distributed in six groups according to diameter (1.5mm, 1.8mm or 2.0mm) and type of anchorage (monocortical and bicortical) in bovine rib. The primary stability was evaluated by insertion torque, micromobility and pull-out strength tests. ANOVA and/or Tukey analysis were used to conduct intergroup comparisons (p< 0.05). Non-parametric statistics (Kruskal-Wallis and Mann-Whitney) were performed when normality was not found (p< 0.05). RESULTS: MIs with larger diameters and bicortical anchorage showed greater primary stability regarding insertion torque (p< 0.05) and micromobility (p< 0.05). Only MI diameter had an effect on the pull-out strength test. Larger diameter MIs presented better retention in pull-out strength tests (p< 0.001), regardless of mono- or bicortical anchorage. CONCLUSIONS: MI primary stability is dependent on its diameter and type of anchorage. Bicortical anchorage showed greater stability when compared with monocortical anchorage, independently of other variables.

Miniscrew-assisted rapid palatal expansion (MARPE): how to achieve greater stability. In vitro study

ABSTRACT Objective: Assess the influence of mono- and bicortical anchorage and diameter of mini-implants (MIs) on the primary stability of these devices. Methods: 60 self-drilling MIs were distributed in six groups according to diameter (1.5mm, 1.8mm or 2.0mm) and type of anchorage (monocortical and bicortical) in bovine rib. The primary stability was evaluated by insertion torque, micromobility and pull-out strength tests. ANOVA and/or Tukey analysis were used to conduct intergroup comparisons (p< 0.05). Non-parametric statistics (Kruskal-Wallis and Mann-Whitney) were performed when normality was not found (p< 0.05). Results: MIs with larger diameters and bicortical anchorage showed greater primary stability regarding insertion torque (p< 0.05) and micromobility (p< 0.05). Only MI diameter had an effect on the pull-out strength test. Larger diameter MIs presented better retention in pull-out strength tests (p< 0.001), regardless of mono- or bicortical anchorage. Conclusions: MI primary stability is dependent on its diameter and type of anchorage. Bicortical anchorage showed greater stability when compared with monocortical anchorage, independently of other variables.

RESUMO Objetivo: Avaliar a influência da ancoragem mono e bicortical e do diâmetro dos mini-implantes (MIs) na estabilidade primária desses dispositivos. Métodos: 60 MIs autoperfurantes foram distribuídos em seis grupos, de acordo com o diâmetro (1,5 mm, 1,8 mm ou 2,0 mm) e tipo de ancoragem (monocortical e bicortical), e inseridos em costela bovina. A estabilidade primária foi avaliada pelos testes de torque de inserção, micromobilidade e resistência à tração. ANOVA e/ou análise de Tukey foram usadas para realizar comparações intergrupos (p< 0,05). Estatística não paramétrica (Kruskal-Wallis e Mann-Whitney) foi realizada quando a normalidade não foi encontrada (p< 0,05). Resultados: MIs com diâmetros maiores e ancorados bicorticalmente apresentaram maior estabilidade primária em relação ao torque de inserção (p< 0,05) e micromobilidade (p< 0,05). Apenas o diâmetro do MI influenciou os resultados do teste de resistência à tração. MIs de maior diâmetro apresentaram melhor retenção nos testes de resistência à tração (p< 0,001), independentemente da ancoragem mono ou bicortical. Conclusões: a estabilidade primária do MI é dependente de seu diâmetro e tipo de ancoragem. A ancoragem bicortical apresentou maior estabilidade quando comparada à ancoragem monocortical, independentemente das demais variáveis.

Is the buccal alveolar bone less affected by mini-implant assisted rapid palatal expansion than by conventional rapid palatal expansion?-A systematic review and meta-analysis.

OBJECTIVE: To systematically review the existing literature comparing mini-implant assisted rapid palatal expansion (MARPE) and conventional rapid palatal expansion (RPE) regarding the effect on the buccal alveolar bone thickness (BT) and marginal bone level (BL). METHODS: PubMed/MEDLINE, Scopus, Web of Science, The Cochrane Library, Virtual Health Library, Embase, Ovid, LIVIVO, CINAHL, the Portal de Periódicos da CAPES, Google Scholar and SIGLE were searched up to January 2020. Risk of bias (RoB) assessments were performed using the Cochrane Collaboration and ROBINS-I tools. Fixed-effects meta-analysis of standardized mean differences (SMD) was implemented to assess the pooled estimates for the BT outcome. The analyses were performed adopting a significance level of 5%. A narrative synthesis was performed to summarize the results on the BL. The GRADE tool was used to assess the quality of the evidence. RESULTS: Three randomized clinical trials and one retrospective study were included. Only one study was rated as with low RoB, while the others were scored as with moderate to serious RoB. Limited evidence indicated that patients using conventional RPE had a greater loss of the BT compared to patients using MARPE (SMD = 0.55; 95% CI: 0.29-0.80; P < .0001). Subgroup analyses showed that differences were significant in both premolars' regions, right (SMD = 0.75; 95% CI: 0.24-1.25; P = .004) and left (SMD = 1.05; 95% CI: 0.52-1.57; P < .0001), and these were not significant for the molars' regions (P > .05) (Low quality of evidence). LIMITATIONS: Limited amount of selected papers, methodological issues that could lead to bias and high clinical heterogeneity among the studies. Due to the statistical model applied for the quantitative synthesis of the results, no generalization to any other population is recommended. CONCLUSIONS: Limited evidence suggests that MARPE could decrease the loss of the buccal alveolar bone when compared to conventional RPE.

Evaluation of facial soft tissue thickness in symmetric and asymmetric subjects with the use of cone-beam computed tomography.

INTRODUCTION: The aims of this study were to evaluate facial bilateral soft tissue thickness in symmetric and asymmetric subjects and to investigate whether soft tissue compensates for skeletal asymmetry. METHODS: Cone-beam computed tomography (CBCT) scans of 97 subjects were divided into a symmetry group (GSm) and an asymmetry group (GASm). Seven bilateral points were established. Each point involved 3 variables: hard tissue distance (Hard-D), soft tissue distance (Soft-D), and soft tissue thickness (Soft-Th). Measurements were taken from software-generated multiplanar reconstructions. A paired t test was used to assess intragroup differences and an independent t test for intergroup analysis. Pearson coefficient tested correlations between variables. RESULTS: In GASm, significant differences were found in all Hard-D and Soft-D measurements, with higher values observed on the deviated side (P <0.01). As for Soft-Th evaluation, results of only 1 reference point presented statistical significance. Intergroup comparison detected significant differences in all Hard-D and Soft-D variables (P <0.01), but no significant differences in Soft-Th. CONCLUSIONS: Asymmetric subjects presented differences in hard and soft tissue distances between deviated and nondeviated sides, although without affecting soft tissue thickness. It can be concluded that soft tissue does not compensate or disguise an underlying skeletal asymmetry.

Three-dimensional study of the upper airway in different skeletal Class II malocclusion patterns.

OBJECTIVES: To characterize upper airway volume and morphology in patients with different skeletal patterns of Class II malocclusion compared to Class I. MATERIALS AND METHODS: A total of 197 individuals who had cone-beam computed tomography were allocated into groups according to ANB, SNA, and SNB angles (Class I, Class II maxillary protrusion, Class II mandibular retrusion), each subdivided into hypodivergent, normal, and hyperdivergent. Nasopharynx (NP), oropharynx (OP), and hypopharynx (HP) were assessed with three-dimensional image reconstruction software. RESULTS: Intergroup comparison did not detect significant differences in volume and morphology of NP, OP, and HP. The males displayed larger OP and HP volume than the females. Positive correlations between age and NP, OP, HP volume and between craniocervical angle and OP and HP volume were observed. Linear regression analysis detected a tendency for OP and HP volume to increase as maxillary and mandibular length increased. CONCLUSIONS: Upper airway volume and morphology were similar in different skeletal patterns of Class II malocclusion. Actual upper and lower jaw lengths were more closely related to upper airway volume and morphology than the angles that reflected their position relative to the cranial base.

The effect of hard tissue surgical changes on soft tissue displacement: a pilot CBCT study.

INTRODUCTION: This pilot study had as main objective to test the reliability of a new method to evaluate orthognathic surgery outcomes and also, to understand the effect of hard tissue changes on soft tissue displacement. METHODS: The sample consisted of eight patients that underwent bimaxillary advancement and had CBCT at two time points (before surgery and 6-8 months follow-up). Voxel-based cranial base superimposition was used to register the scans. A different technique of iterative closest point (ICP) was used to measure and correlate the changes. The average displacement of 15 areas (4 hard tissue and 11 soft tissue) were measured twice. RESULTS: ICC was > 0.99 for all areas. Changes in the tip of the nose did not correlate with changes in any maxillary area, whereas soft tissue A point, A point and upper lips had correlation with several areas. The highest correlation for the maxilla was between the upper lip and the left/right supra cheilion (p< 0.001, r= 0.91 and p< 0.001, r= 0.93, respectively). In the mandible, the majority of the correlations involved soft tissue pogonion, pogonion and lower incisors, with the strongest one between pogonion and lower incisors (p< 0.001, r= 0.98). CONCLUSION: With the proper case selection, ICP is a reliable method that can be used to assess three-dimensional changes.

The effect of hard tissue surgical changes on soft tissue displacement: a pilot CBCT study

ABSTRACT Introduction: This pilot study had as main objective to test the reliability of a new method to evaluate orthognathic surgery outcomes and also, to understand the effect of hard tissue changes on soft tissue displacement. Methods: The sample consisted of eight patients that underwent bimaxillary advancement and had CBCT at two time points (before surgery and 6-8 months follow-up). Voxel-based cranial base superimposition was used to register the scans. A different technique of iterative closest point (ICP) was used to measure and correlate the changes. The average displacement of 15 areas (4 hard tissue and 11 soft tissue) were measured twice. Results: ICC was > 0.99 for all areas. Changes in the tip of the nose did not correlate with changes in any maxillary area, whereas soft tissue A point, A point and upper lips had correlation with several areas. The highest correlation for the maxilla was between the upper lip and the left/right supra cheilion (p< 0.001, r= 0.91 and p< 0.001, r= 0.93, respectively). In the mandible, the majority of the correlations involved soft tissue pogonion, pogonion and lower incisors, with the strongest one between pogonion and lower incisors (p< 0.001, r= 0.98). Conclusion: With the proper case selection, ICP is a reliable method that can be used to assess three-dimensional changes.

RESUMO Objetivo: o objetivo deste estudo piloto foi testar a confiabilidade de um novo método para avaliar os resultados da cirurgia ortognática e entender o efeito das alterações dos tecidos duros no deslocamento dos tecidos moles. Métodos: a amostra selecionada consistiu de oito pacientes submetidos a avanço bimaxilar que possuíam TCFC em dois períodos de tempo (antes da cirurgia e de 6 a 8 meses após a cirurgia). A sobreposição da base do crânio pelo método voxel-based foi utilizada para registrar as varreduras, enquanto uma técnica diferente, de ponto iterativo mais próximo (ICP), foi usada para medir e correlacionar as mudanças. O deslocamento médio de 15 áreas (4 em tecidos duros e 11 em tecidos moles) foi mensurado duas vezes. Resultados: o ICC foi > 0,99 para todas as áreas. As alterações da ponta do nariz não se correlacionaram com alterações em qualquer área da maxila, enquanto o ponto A em tecido mole, o ponto A e os lábios superiores apresentaram correlação com várias áreas. A maior correlação para a maxila foi entre o lábio superior e a supracomissura esquerda/direita (p< 0,001, r = 0,91 e p< 0,001, r = 0,93, respectivamente). Na mandíbula, a maioria das correlações envolveu o pogônio em tecido mole, pogônio e incisivos inferiores, sendo a maior entre pogônio e incisivos inferiores (p< 0,001, r= 0,98). Conclusão: com a seleção adequada do caso, o ICP é um método confiável que pode ser utilizado para avaliar mudanças tridimensionais.

Non-surgical treatment of transverse deficiency in adults using Microimplant-assisted Rapid Palatal Expansion (MARPE).

INTRODUCTION: Maxillary transverse deficiency is a highly prevalent malocclusion present in all age groups, from primary to permanent dentition. If not treated on time, it can aggravate and evolve to a more complex malocclusion, hindering facial growth and development. Aside from the occlusal consequences, the deficiency can bring about serious respiratory problems as well, due to the consequent nasal constriction usually associated. In growing patients, this condition can be easily handled with a conventional rapid palatal expansion. However, mature patients are frequently subjected to a more invasive procedure, the surgically-assisted rapid palatal expansion (SARPE). More recently, researches have demonstrated that it is possible to expand the maxilla in grown patients without performing osteotomies, but using microimplants anchorage instead. This novel technique is called microimplant-assisted rapid palatal expansion (MARPE). OBJECTIVE: The aim of the present article was to demonstrate and discuss a MARPE technique developed by Dr. Won Moon and colleagues at University of California - Los Angeles (UCLA). METHODS: All laboratory and clinical steps needed for its correct execution are thoroughly described. For better comprehension, a mature patient case is reported, detailing all the treatment progress and results obtained. CONCLUSION: It was concluded that the demonstrated technique could be an interesting alternative to SARPE in the majority of non-growing patients with maxillary transverse deficiency. The present patient showed important occlusal and respiratory benefits following the procedure, without requiring any surgical intervention.

Camouflage of a high-angle skeletal Class II open-bite malocclusion in an adult after mini-implant failure during treatment.

The treatment of skeletal anterior open-bite malocclusion requires complex orthodontic planning that considers its multifactorial etiology, treatment limitations, and high relapse rates. This case report illustrates a successful treatment approach for a skeletal high-angle Class II malocclusion in an adult with a severe open bite. The treatment consisted of a high-pull headgear therapy after mini-implants failure during fixed orthodontic therapy. Adequate esthetics and function were achieved. Despite its low probability, the unexpected event of mini-implant loosening during complex treatments should be considered. Therefore, classic orthodontic mechanics should be established, especially when treating patients for whom invasive procedures such as miniplates or orthognathic surgery are not available options.

Non-surgical treatment of transverse deficiency in adults using Microimplant-assisted Rapid Palatal Expansion (MARPE)

ABSTRACT Introduction: Maxillary transverse deficiency is a highly prevalent malocclusion present in all age groups, from primary to permanent dentition. If not treated on time, it can aggravate and evolve to a more complex malocclusion, hindering facial growth and development. Aside from the occlusal consequences, the deficiency can bring about serious respiratory problems as well, due to the consequent nasal constriction usually associated. In growing patients, this condition can be easily handled with a conventional rapid palatal expansion. However, mature patients are frequently subjected to a more invasive procedure, the surgically-assisted rapid palatal expansion (SARPE). More recently, researches have demonstrated that it is possible to expand the maxilla in grown patients without performing osteotomies, but using microimplants anchorage instead. This novel technique is called microimplant-assisted rapid palatal expansion (MARPE). Objective: The aim of the present article was to demonstrate and discuss a MARPE technique developed by Dr. Won Moon and colleagues at University of California - Los Angeles (UCLA). Methods: All laboratory and clinical steps needed for its correct execution are thoroughly described. For better comprehension, a mature patient case is reported, detailing all the treatment progress and results obtained. Conclusion: It was concluded that the demonstrated technique could be an interesting alternative to SARPE in the majority of non-growing patients with maxillary transverse deficiency. The present patient showed important occlusal and respiratory benefits following the procedure, without requiring any surgical intervention.

RESUMO Introdução: a deficiência transversa da maxila é uma má oclusão com alta prevalência em todas as faixas etárias, da dentição decídua à permanente. Se não for corrigida, pode agravar-se com o passar do tempo, prejudicando o crescimento e desenvolvimento facial. Além dos prejuízos oclusais, essa deficiência pode trazer problemas respiratórios também severos, devido à consequente constrição da cavidade nasal. Em pacientes em crescimento, a sua resolução é relativamente simples, por meio da expansão rápida convencional da maxila. Porém, os pacientes já maduros geralmente são encaminhados para um procedimento mais invasivo, a expansão rápida de maxila assistida cirurgicamente (SARPE). Mais recentemente, pesquisadores têm demonstrado que é possível executar a expansão palatal esquelética em pacientes adultos sem auxílio de osteotomias, mas sim com auxílio de mini-implantes. Essa técnica é denominada Microimplant-Assisted Rapid Palatal Expansion, ou MARPE. Objetivo: o objetivo do presente artigo é demonstrar e discutir uma das técnicas disponíveis de MARPE, desenvolvida por Won Moon e colaboradores, na University of California, Los Angeles (UCLA). Métodos: a técnica encontra-se detalhadamente descrita, com as etapas laboratoriais e clínicas que devem ser seguidas para sua correta execução. Para descrevê-la, é apresentado o caso clínico de uma paciente adulta, detalhando toda a sequência do tratamento e os resultados obtidos. Conclusão: a técnica apresentada pode ser uma alternativa não invasiva à SARPE na resolução da deficiência transversa de maxila, podendo ser empregada na maioria dos pacientes com crescimento facial finalizado. A paciente apresentada demonstrou benefícios significativos nos aspectos oclusal e respiratório, sem a necessidade de intervenção cirúrgica.

Prediction of 3-dimensional pharyngeal airway changes after orthognathic surgery: a preliminary study.

INTRODUCTION: Recent studies have shown some contradictory results when evaluating the consequences of orthodontic-surgical treatments on the pharyngeal airway. Therefore, the purpose of this study was to correlate the amount of jaw displacement with the volume variation and the minimal cross-sectional area of the pharyngeal airway. A comparison was made between the correlations with the percentage and the absolute values of the measurement variations. METHODS: Forty-two patients were divided into 2 groups according to the kind of orthognathic surgery that they had undergone. Group 1 had 22 subjects who had undergone maxillary advancement associated with mandibular setback, and group 2 had 20 patients who had undergone maxillomandibular advancement. The pharyngeal airway was divided into the upper segment and the lower segment, and the sum of these volumetric measures resulted in the total volume. The maxillary and mandibular displacements were assessed using closest point iteration after a voxel-wise cone-beam computed tomography superimposition. Hence, jaw displacements were correlated, using Pearson's correlation and linear regression analysis, to the volume variations of the pharyngeal airway (first time separately and then both groups together) and to the minimal cross-sectional area variation. RESULTS: The strongest correlation found was between maxillary displacement and the upper segment in group 2 (r = 0.898, R(2) = 0.888; P ≤0.001). With the groups' data combined, the variables mandibular displacement and the lower segment showed a linear correlation (r = 0.921, R(2) = 0.914; P ≤0.001). Maxillary displacement showed a strong positive correlation with the minimal cross-sectional area variation in group 2 (r = 0.710, R(2) = 0.604; P ≤0.01). CONCLUSIONS: Correlations with the percentage values were substantially stronger than the correlations with the absolute values. Stronger positive correlations were found between the jaw's displacement and the volume variation of the volume segment that was closer to it in both kinds of surgeries. Only the maxillary displacement is a reliable predictor of the minimal cross-sectional area variation after maxillomandibular advancement.

Reliability of CBCT in the diagnosis of dental asymmetry.

OBJECTIVE: The aim of this study was to validate a method used to assess dental asymmetry, in relation to the skeletal midline, by means of CBCT. METHODS: Ten patients who had CBCT scans taken were randomly selected for this study. Five different observers repeated 10 landmarks (x, y and z variables for each) and 12 linear measurements within 10 days. Measurements were taken in both arches to evaluate symmetry of first molars, canines and dental midline in relation to the skeletal midline. Intraclass correlation coefficient (ICC) was carried out to assess intra- and interobserver reliability for landmarks and distances. Average mean difference was also assessed to check measurement errors between observers. RESULTS: ICC for the landmarks was, respectively, ≥ 0.9 for 27 (90%) and 25 (83%) variables for intra- and interobserver; ICC for distances was ≥ 0.9 for 7 (58%) and 5 (42%), respectively. All ICC landmarks for distances were >0.75 for both intra- and interobserver. The mean difference between observers was ≤ 0.6 mm for all the distances. CONCLUSION: The method used to assess dental asymmetry by means of CBCT is valid. Measurements of molars, canines and dental midline symmetry with the skeletal midline are reproducible and reliable when taken by means of CBCT and by different operators.

Reliability of CBCT in the diagnosis of dental asymmetry

Objective: The aim of this study was to validate a method used to assess dental asymmetry, in relation to the skeletal midline, by means of CBCT. Methods: Ten patients who had CBCT scans taken were randomly selected for this study. Five different observers repeated 10 landmarks (x, y and z variables for each) and 12 linear measurements within 10 days. Measurements were taken in both arches to evaluate symmetry of first molars, canines and dental midline in relation to the skeletal midline. Intraclass correlation coefficient (ICC) was carried out to assess intra- and interobserver reliability for landmarks and distances. Average mean difference was also assessed to check measurement errors between observers. Results: ICC landmarks was ≥ 0.9 for 27 (90%) and 25 (83%) variables for intra- and interobserver, respectively. ICC for distances was ≥ 0.9 for 7 (58%) and 5 (42%), respectively. All ICC landmarks for distances were >0.75 for both intra- and interobserver. The mean difference between observers was ≤ 0.6 mm for all the distances. Conclusion: The method used to assess dental asymmetry by means of CBCT is valid. Measurements of molars, canines and dental midline symmetry with the skeletal midline are reproducible and reliable when taken by means of CBCT and by different operators. .

Objetivo: validar um método para avaliar assimetria dentária, em relação à linha média esquelética, usando TCFC. Métodos: dez pacientes que realizaram TCFC foram selecionados aleatoriamente para esse estudo. Cinco diferentes observadores repetiram 10 pontos de referência (com variáveis x, y e z, para cada ponto) e 12 medidas lineares em um intervalo de 10 dias. As medições foram realizadas em ambas as arcadas, para avaliar a simetria de primeiros molares, caninos e linha média dentária, em relação à linha média esquelética. Índice de correlação intraclasse (ICC) foi realizado para verificar a confiabilidade intraobservador e interobservadores para os pontos de referência e distâncias. A diferença média também foi avaliada, para checar os erros de mensuração entre os observadores. Resultados: ICC para os pontos de referência foram ≥ 0,9 para 27 (90%) e 25 (83%) das variáveis para intra- e interobservadores respectivamente. ICC para distâncias foi ≥ 0,9 para 7 (58%) e 5 (42%), respectivamente. Todas as medidas de ICC para distâncias foram > 0,75 para intraobservador e interobservadores. A diferença média entre observadores foi ≤ 0,6mm para todas as distâncias. Conclusão: o método de verificação de assimetria dentária utilizando TCFC é válido. Medições de molares, caninos e linha média dentária com a linha média esquelética são reproduzíveis e confiáveis quando feitas utilizando TCFC, mesmo que por diferentes operadores. .

Comparison of shear bond strength of orthodontics brackets on composite resin restorations with different surface treatments.

INTRODUCTION: Orthodontic patients frequently present composite resin restorations, however there are few studies that evaluate the best way for orthodontic bonding in this situation. OBJECTIVE: The objective of this work was to evaluate the bond strength of orthodontic brackets in resin restorations with surface treatment. METHODS: Fifty one bovine lower incisors were randomly divided into three groups. On the control group (CG) the brackets were bonded to dental enamel; on experimental groups, brackets were bonded to resin restoration with diamond drill treatment (EGT) and with no treatment (EGN). The teeth were placed in PVC tubes with self-etching acrylic resin. The shear test was performed in EMIC universal testing machine. The groups were submitted to ANOVA analysis of variance with Tukey post test to verify the statistical difference between groups (α = 0.05). RESULTS: CG (6.62 MPa) and EGT (6.82 MPa) groups presented similar results, while EGN (5.07 MPa) obtained statistically lower results (p < 0.05). CONCLUSIONS: Therefore, it is concluded that the best technique for bonding orthodontic brackets on composite resin restorations is the performance of surface detritions.

Comparison of shear bond strength of orthodontics brackets on composite resin restorations with different surface treatments

INTRODUCTION: Orthodontic patients frequently present composite resin restorations, however there are few studies that evaluate the best way for orthodontic bonding in this situation. OBJECTIVE: The objective of this work was to evaluate the bond strength of orthodontic brackets in resin restorations with surface treatment. METHODS: Fifty one bovine lower incisors were randomly divided into three groups. On the control group (CG) the brackets were bonded to dental enamel; on experimental groups, brackets were bonded to resin restoration with diamond drill treatment (EGT) and with no treatment (EGN). The teeth were placed in PVC tubes with autopolymerized acrylic resin. The shear test was performed in EMIC universal testing machine. The groups were submitted to ANOVA analysis of variance with Tukey post test to verify the statistical difference between groups (α = 0.05). RESULTS: CG (6.62 MPa) and EGT (6.82 MPa) groups presented similar results, while EGN (5.07 MPa) obtained statistically lower results (p < 0.05). CONCLUSION: Therefore, it is concluded that the best technique for bonding of orthodontic brackets on composite resin restorations is the performance of surface detritions.

INTRODUÇÃO: frequentemente, os pacientes ortodônticos apresentam restaurações de resina composta; no entanto, existem poucos estudos que avaliam a melhor forma de colagem ortodôntica nessa situação. OBJETIVO: o objetivo do presente trabalho foi avaliar a força adesiva de braquetes ortodônticos em restaurações resinosas com tratamento de superfície. MÉTODOS: foram utilizados 51 incisivos inferiores bovinos divididos aleatoriamente em três grupos. No grupo controle (GC), os braquetes foram colados em esmalte dentário; nos grupos experimentais com tratamento (GCT) e sem tratamento (GST), os braquetes foram colados em restauração de resina previamente realizada, diferenciando-se pelo tratamento de superfície com broca diamantada. Os dentes foram incluídos em tubos de PVC com resina acrílica autopolimerizável. O ensaio de cisalhamento foi executado em máquina universal de ensaios Emic. Os grupos foram submetidos à ANOVA com pós-teste de Tukey para verificação da diferença estatística entre os grupos (α = 0,05). RESULTADOS: GC (6,62MPa) e GCT (6,82MPa) apresentaram resultados semelhantes, enquanto o GST (5,07MPa) obteve resultados estatisticamente menores (p < 0,05). CONCLUSÃO: conclui-se que a melhor técnica de colagem de braquetes ortodônticos em restaurações de resina composta é a de realização de desgaste sobre a superfície.