Discrepancia dentaria de Bolton y finalización de ortodoncia: consideraciones clínicas / Bolton tooth size discrepancy and orthodontics finalization: clinical considerations

Las discrepancias entre el tamaño mesiodistal de los dientes superiores e inferiores, así como sus efectos sobre la oclusión han sido reportadas desde mediados del siglo XX. El objetivo de este estudio fue determinar la importancia de la aplicación del análisis de discrepancias dentaria de Bolton con finalidad ortodontica. Fueron seleccionados casos de pacientes de raza blanca de ambos sexos, con edades comprendidas entre 12 y 25 años. El análisis de las discrepancias dentarias fue realizado en la fase previa al tratamiento y posterior a la contención. Como criterio básico para la inclusión en la muestra de pacientes en el pre-tratamiento deberían presentar todos los dientes permanentes (de primeros molares a primeros molares del lado opuesto, en ambos arcos). Fueron eliminados los casos que presentaron dientes con grandes destrucciones, restauraciones inadecuadas y dientes mal posicionados donde no fue posible la medición adecuada entre los puntos de contacto. La medición del tamaño mesiodistal de los dientes se realizó con un caliper (Odin, Alemania), precisión de 0,01 mm, por un solo examinador, previamente calibrado para realizar este procedimiento. Se midió el diámetro mesiodistal mayor de todos los dientes. Las relaciones totales y anteriores fueron calculadas por las fórmulas respectivas, según lo propuesto por Bolton (1958). Al finalizar, los casos mostraron que una discrepancia dentaria de Bolton maxilar o mandibular por exceso o falta dentaria, puede ser compensada por la alteración en la forma del arco, dimensión vestibulolingual y por la inclinación axial de los dientes anteriores, utilizadas en conjunto o aisladamente en la arcada, sin perjuicio estético y funcional.

Discrepancies of the mesiodistal dimensions between upper and lower teeth as well as their effects on occlusion have been reported since the middle of the twentieth century. The aim of this study was to elucidate the importance of the applicability of the analysis of the Bolton tooth size discrepancy in the orthodontic finalizing. Cases involving Caucasian male and female patients aged between 12 and 25 years were selected for study. Analyses of the dental discrepancies were carried out before orthodontic treatment and after contention. Basically, only patients having all permanent teeth before treatment (with first molars in both arches) were included. Those cases of severely mutilated teeth, inadequate restorations, and tooth malalignment were ruled out because accurate measurement of the contacting points could not be performed. Measurement of the mesiodistal tooth dimension was performed by only one operator using a digital calliper of a resolution of 0.001 mm (Odin, Germany) which had been previously calibrated for such procedures. It was measured the largest mesiodistal diameter. Both previous and total relationships were calculated through their respective formulas according to Bolton (1958). The orthodontic finalisation showed that Bolton tooth size discrepancies involving either crowded dentition or lack of teeth can be compensated by mandibular or maxillary arch shape, buccal-lingual dimension, and axial inclination of the anterior teeth with no aesthetic or functional impairment.

Avaliação do apinhamento ântero-inferior por meio da análise de Bolton / Evaluation of lower incisal crowding by Bolton's analysis

Sabendo-se que a proporção entre o tamanho dos dentes superiores e inferiores é de fundamental importância para a finalização dos casos ortodônticos e que o apinhamento constitui uma das maiores causas de procura pelo tratamento ortodôntico, objetivou-se no presente estudo, avaliar com que frequência os pacientes com apinhamento na região ântero-inferior apresentam discrepância de tamanho dentário, bem como mensurar a quantidade do apinhamento que poderia estar relacionado com o excesso de estrutura dentária. A amostra foi constituída por 40 pares de modelos de gesso da documentação inicial de pacientes com apinhamento ântero-inferior, brasileiros, leucodermas, tanto do gênero masculino quanto do feminino. Foram utilizados os índices da Análise de Bolton para a avaliação da proporção entre os tamanhos dentários, e os resultados permitiram concluirque: l. Da amostra estudada, 57,5% tinham algum tipo de discrepância de tamanho dentário; 2. Em 52,5% da amostra, os pacientes apresentavam excesso de tamanho dentário na região anterior do arco inferior; 3. Os valores mínimo, máximo e a médiada discrepância de modelo, na amostra estudada, foram de 2 mm, 6 mm e 4,17 mm, respectivamente; e 4. Os valores mínimo, máximo e a média da discrepância de Bolton, para a amostra estudada, na região ântero-inferior foram de 1,22 mm, 3,74 mme 2, 13mm, respectivamente.

Knowing that the proportion between the size of maxillary and mandibular teeth is of fitndamental importance for finalizingorthodontic cases and that crowding is one ofthe major causes for seeking orthodontic treatment, the aim ofthis study was to assess the frequency with which patients with crowding in the antero-mandibular region present tooth size discrepancy, as well as to measurelheamount of crowding that may be related to excessive tooth structure. The sample comprised 40 pairs of plaster models from the original documentation of Brazilian, leucoderm patients of both genders, with antero-mandibular crowding. The Bolton analysisindexes were used to assess the proportion between the tooth sizes and the results allowed one to conclude that: 1. Ofthe studied sample, 57.5% had some type oftooth size discrepancy; 2. In 52.5% ofthe sample, the patients presented with excessive tooth sizein lhe anlerior region ofthe mandibular arch; 3. The minimum, maximum and mean model discrepancy values in the studied sample the were as follows: 2 mm, 6 mm and 4.17 mm, respectively; and 4. The minimum, maximum and mean Bolton discrepancy values forlhe studied sample, in the antero-mandibular region were as follows: 1.22 mm, 3.74 mm and 2.13 mm, respectively.