Occlusion development after premature loss of deciduous anterior teeth: preliminary results of a 24-month prospective cohort study.

OBJECTIVE: This study aimed to evaluate occlusion development after premature loss or extraction of deciduous anterior teeth, by means of a prospective cohort study. METHODS: Fifteen infants and children aged 1 to 5 years old were longitudinally assessed (with loss or extraction of deciduous anterior teeth [n = 9], and without tooth losses [n = 6]). Photographs and dental casts at the baseline and after 24 months of follow-up were performed. Dental casts were scanned, and linear measurements were made on the digitalized models (missing tooth space, arch perimeter, arch length, arch width, intercanine length and intercanine width). The t-test was used for groups comparisons (α = 0.05). RESULTS: Individuals' mean age at baseline was 2.93 (± 1.18) years. No statistically significant differences were observed in the missing tooth space in the group with tooth loss during the 24 months of follow-up (p > 0.05). Arch perimeter, arch length, arch width, intercanine length and intercanine width did not show differences between the groups (p > 0.05). Qualitative photographic evaluation revealed other changes in the dental arches and occlusion, such as exfoliation and eruption of deciduous teeth, eruption of permanent teeth, self-correction or establishment of malocclusion, among others. CONCLUSION: The results suggest that the premature loss of deciduous anterior teeth does not affect the perimeter, length and width of the dental arches; however, other alterations that lead to malocclusion could be established.

Occlusion development after premature loss of deciduous anterior teeth: preliminary results of a 24-month prospective cohort study

ABSTRACT Objective: This study aimed to evaluate occlusion development after premature loss or extraction of deciduous anterior teeth, by means of a prospective cohort study. Methods: Fifteen infants and children aged 1 to 5 years old were longitudinally assessed (with loss or extraction of deciduous anterior teeth [n = 9], and without tooth losses [n = 6]). Photographs and dental casts at the baseline and after 24 months of follow-up were performed. Dental casts were scanned, and linear measurements were made on the digitalized models (missing tooth space, arch perimeter, arch length, arch width, intercanine length and intercanine width). The t-test was used for groups comparisons (α = 0.05). Results: Individuals' mean age at baseline was 2.93 (± 1.18) years. No statistically significant differences were observed in the missing tooth space in the group with tooth loss during the 24 months of follow-up (p > 0.05). Arch perimeter, arch length, arch width, intercanine length and intercanine width did not show differences between the groups (p > 0.05). Qualitative photographic evaluation revealed other changes in the dental arches and occlusion, such as exfoliation and eruption of deciduous teeth, eruption of permanent teeth, self-correction or establishment of malocclusion, among others. Conclusion: The results suggest that the premature loss of deciduous anterior teeth does not affect the perimeter, length and width of the dental arches; however, other alterations that lead to malocclusion could be established.

RESUMO Objetivo: Este estudo teve como objetivo avaliar o desenvolvimento da oclusão após perda prematura ou extração de dentes decíduos anteriores, por meio de um estudo de coorte prospectivo. Métodos: Quinze bebês e crianças de 1 a 5 anos foram avaliados longitudinalmente (com perda ou extração de dentes anteriores decíduos [n = 9] e sem perdas dentárias [n = 6]). Foram realizadas fotografias e modelos dentais no início e após 24 meses de acompanhamento. Os modelos dentários foram escaneados e medidas lineares foram feitas nos modelos digitalizados (espaço dentário perdido, perímetro da arcada, comprimento da arcada, largura da arcada, comprimento intercaninos e largura intercaninos). O teste t foi utilizado para comparações entre grupos (α = 0,05). Resultados: A média de idade dos indivíduos no início do estudo foi de 2,93 (± 1,18) anos. Não foram observadas diferenças estatisticamente significativas no espaço dentário perdido no grupo com perda dentária durante os 24 meses de acompanhamento (p > 0,05). O perímetro da arcada, comprimento da arcada, largura da arcada, comprimento intercaninos e largura intercaninos não apresentaram diferenças entre os grupos (p> 0,05). A avaliação fotográfica qualitativa revelou alterações nas arcadas dentárias e na oclusão, como: esfoliação e erupção de dentes decíduos, erupção de dentes permanentes, autocorreção ou estabelecimento de má oclusão, entre outras. Conclusão: Os resultados sugerem que a perda prematura de dentes anteriores decíduos não afeta o perímetro, comprimento e largura das arcadas dentárias; entretanto, outras alterações que levam à má oclusão poderiam ser estabelecidas.

Effect of oral exposure on chemical, physical, mechanical, and morphologic properties of clear orthodontic aligners

The dental industry is heavily committed to developing more esthetic solutions for orthodontic treatments. Invisalign is a system of transparent orthodontic aligners introduced as an alternative to conventional orthodontic fittings with brackets and metal wires. This study aimed to assess the chemical, physical, mechanical and morphologic changes in these polymeric aligners after exposure to the oral environment. Twenty-four Invisalign orthodontic aligners were equally divided into 2 groups: an in vivo aged group in which patients used aligners for 14 days and the reference group, unexposed to the oral environment. Different experimental techniques were used to study the chemical structure, the color changes and translucency, the density and subsequent volume of the aligners, mechanical properties, surface roughness, morphology and elemental composition. The data were subjected to several statistical analyses. Clear orthodontic aligners exhibit chemical stability but undergo a statistically significant optical change in color and translucency. There was a gradual increase in the water absorption rate and the dimensional variation of the polymer, indicating a strong correlation among these factors. The mechanical properties of the polymer showed a statistically significant decrease in its elastic modulus and hardness. There was a slight tendency toward increased surface roughness of the material, but no statistical differences were found between reference and aged groups. The surface morphology of the used aligners demonstrates microcracks, distortions and biofilm formation. Intraoral aging adversely affected the physical, mechanical, and morphologic properties of the Invisalign appliance.

Impact of oral-health-related quality of life and self-esteem on patients with missing maxillary lateral incisor after orthodontic space closure: a single-blinded, randomized, controlled trial.

BACKGROUND: The maxillary lateral incisor is one of the teeth most likely to suffer agenesis, resulting in spacing between the central incisor and the canine. OBJECTIVE: To compare maxillary lateral incisor agenesis with space closure treatment versus non-treatment based on measurements of the self-perceived oral-health-related quality of life (OHRQoL) and self-esteem of the participants. SUBJECTS AND METHODS: A total of 44 people, aged 17-49 years, with missing lateral incisors were randomly assigned to two groups (n = 22 in each)-a treated group in which the space was orthodontically closed (TG) and a control group that remained untreated (CG). Randomization was performed by a researcher who was not involved in the clinical part of the study. The outcomes were assessed using the Oral Health Impact Profile and Rosenberg's Self-Esteem Scale, which were applied before (phase 1) and after (phase 2) the orthodontic treatment in the TG, and at baseline (phase 1) and 12 months after (phase 2) in the CG. All the data were blindly evaluated, supporting the single-blinded design of the study. RESULTS: All participants finished the randomized controlled trial, and the demographic characteristics were similar between the groups. In phase 1, the levels of self-esteem and OHRQoL at baseline were similar (P = 0.079, P = 0.693, respectively). In phase 2, the self-esteem scores of the CG decreased and the OHRQoL increased (P = 0.005, P < 0.001, respectively), while self-esteem increased in the TG and the OHRQoL decreased (P < 0.001). The CG had lower scores than the TG for self-esteem, but the opposite was observed for OHRQoL (P < 0.001). LIMITATIONS: Information bias may have occurred. Since the questionnaires could not have been applied at the same time in both groups, the time difference between the two assessments may have led to random and systematic error. CONCLUSIONS: The spacing resulting from missing maxillary lateral incisors had a negative impact on the OHRQoL and self-esteem of the participants, while orthodontically closing those spaces had a positive impact on those aspects. CLINICAL TRIAL REGISTRATION: This study was not registered. PROTOCOL: The protocol was not published before trial commencement.

Mandibular buccal shelf and infrazygomatic crest thicknesses in patients with different vertical facial heights.

INTRODUCTION: The purpose of this study was to use cone-beam computed tomography (CBCT) to determine bone thickness in the mandibular buccal shelf (MBS) and the infrazygomatic crest (IC) in individuals with different vertical facial heights for ultimate placement of miniscrews. METHODS: The sample consisted of 100 individuals aged at least 16 years, of whom 58 were women, and 42 were men. The mean age was 19.18 years (± 5.5 standard deviation). The patients' facial height was determined by the gonial angle. Cross-sectional slices of the MBS and IC were obtained with CBCT to evaluate bone thickness for the insertion of miniscrews in these extra-alveolar sites. Spearman's nonparametric test was used to correlate the gonial angle with MBS and IC thickness. The level of significance was 5%. RESULTS: The gonial angle ranged from 102.4° to 143.2°. Bone thickness in the MBS increased posteriorly, whereas bone thickness in the IC decreased posteriorly. There was an inversely proportional correlation between the gonial angle and the MBS. There was no correlation between the IC and the gonial angle. CONCLUSIONS: Short-faced individuals had higher bone thickness values in the MBS than long-faced ones. There was no correlation between the patients' vertical face height and the bone width in the IC. The best site to install miniscrews in the MBS is buccal to the second molar distal root, whereas in the IC, it is buccal to the first molar mesiobuccal root. CBCT may be necessary to install extra-alveolar miniscrews correctly, especially in the IC.

Influência do padrão vertical em sítios extra alveolares / Influence of vertical pattern on extra-alveolar sites

O objetivo deste estudo foi determinar a espessura óssea no shelf mandibular e na crista infrazigomática em indivíduos com diferentes alturas faciais verticais por meio de tomografia computadorizada de feixe cônico. Para isso, a amostra foi constituída por 100 indivíduos com pelo menos 16 anos de idade, sendo 58 mulheres e 42 homens. A média de idade foi de 19,18 anos de idade (+ - 5,5 DP). A determinação dos pacientes com diferentes alturas faciais foi realizada utilizando o ângulo goníaco, que foi utilizado como medida de referência. Cortes transversais do shelf mandibular e da crista infrazigomática foram realizados nas tomografias para avaliar a espessura óssea nesses sítios extra-alveolares. O teste não paramétrico de Spearman foi utilizado para correlacionar o ângulo goníaco com as espessuras ósseas nas regiões extraalveolares. O nível de significância foi de 5%. Como resultados, observou-se que o ângulo goníaco variou de 102,4º a 143,2º. A espessura transversal e vertical do shelf mandibular aumentou posteriormente, independentemente do ângulo goníaco. Na crista infrazigomática, a espessura do osso diminuiu posteriormente. Houve uma correlação inversamente proporcional entre o ângulo goníaco e o shelf mandibular. Não houve correlação entre a espessura da crista infrazigomática e o ângulo goníaco. Concluiu-se que os pacientes com face curta apresentaram valores mais elevados de espessura óssea no shelf mandibular quando comparados aos de face longa. Não há correlação entre a altura vertical do rosto do paciente e a espessura óssea na crista infrazigomática. O melhor local para a instalação de mini-implantes no shelf mandibular é vestibular à raiz distal do segundo molar, enquanto na crista infrazigomática, vestibular à raiz mésio-vestibular do primeiro molar. (AU)

The purpose of this study was to use CBCT to determine bone thickness in the mandibular buccal shelf (MBS) and the infrazygomatic crest (IC) in individuals with different vertical facial heights for ultimate placement of miniscrews. The sample consisted of 100 individuals aged at least 16 years, of whom 58 were women and 42 were men. The mean age was 19.18 years of age (± 5.5 SD). The patients' facial height was determined by the gonial angle. Cross-sectional slices of the MBS and IC were obtained with CBCT to evaluate bone thickness for insertion of miniscrews in these extra-alveolar sites. Spearman's nonparametric test was used to correlate the gonial angle with MBS and IC thickness. The level of significance was 5%. The gonial angle ranged from 102.4º to 143.2º. Bone thickness in the MBS increased posteriorly, whereas bone thickness in the IC decreased posteriorly. There was an inversely proportional correlation between the gonial angle and the MBS. There was no correlation between the IC and the gonial angle. Short-faced individuals had higher bone thickness values in the MBS than long-faced ones. There was no correlation between the patients' vertical face height and the bone width in the IC. The best site to install miniscrews in the MBS is buccal to the second molar distal root, whereas in the IC it is buccal to the first molar mesiobuccal root. CBCT may be necessary to correctly install extra-alveolar miniscrews, especially in the IC. (AU)

Influence of Primekote® polymer in orthodontic bonding / Influência do polímero Primekote® na colagem ortodôntica

Objective: The Primekote® (TP) polymer was incorporated to the of Orthodontic Bracket mesh base to improve bond strength and make it more efficient. The purpose of this study was to assess the shear bond strength and adhesive remnant index (ARI) of these brackets. Material and method: The test sample consisted of thirty bovine incisors divided into 2 groups: with a group with TP® brackets (n=15), and a control group with Morelli® brackets (n=15) without Primekote® technology. The TransbondTM XT was used as adhesive system in both groups, following the same protocol and manufacturer’s instructions. Specimens were stored in distilled water for 24 hours and then submitted to shear bond strength test in a universal testing machine (EMIC DL2000). The assessment of ARI was performed under stereomicroscope by two calibrated examiners. Result: No significant differences (p>0.05) in shear bond strength were found between the two groups according to the independent t-test. The Wilcoxon test was used to assess ARI data and statistical difference was found between Morelli® and TP® Nu-Edge brackets; the last one left less remaining adhesive on tooth surface. Conclusion: TP® brackets had higher adherence to the adhesive system as shown by lower ARI scores, but this does not improve its clinical performance.

Objetivo: Avaliar a resistência ao cisalhamento e o índice de remanescente adesivo (IRA) dos bráquetes que tiveram o polímero Primekote® incorporado a suas bases. Material e método: Foram confeccionados trinta corpos de prova com incisivos bovinos, divididos em dois grupos: o colado com bráquete TP® Nu-Edge(n=15) e grupo controle com bráquetes Morelli® (n=15) sem tratamento na base. O sistema adesivo TransbondTM XT foi utilizado nos dois grupos seguindo o mesmo protocolo de colagem e respeitando as instruções do fabricante. Os corpos de prova foram armazenados em água destilada por 24 horas, e posteriormente submetidos ao teste de cisalhamento na máquina de ensaios universais (EMIC-DL2000). O IRA foi avaliado por dois examinadores calibrados utilizando lupa estereoscópica com aumento de 20 vezes. Resultado: Na resistência ao cisalhamento o teste T-independente mostrou não haver diferença estatisticamente significante entre os grupos (p>0,05), ambos tiveram desempenho semelhante. O teste Wilcoxon foi utilizado nos valores obtidos no IRA revelando diferença estatística, sendo que os bráquetes TP® deixaram menos remanescente adesivo na superfície dental que os bráquetes Morelli®. Conclusão: Bráquetes TP® apresentaram maior adesão ao sistema adesivo pois foi encontrado menor IRA nos mesmos, porém esta característica não reflete em melhora no desempenho clínico.