Measurement of Mandibular Growth Using Cone-Beam Computed Tomography: A Miniature Pig Model Study

Abstract

The purpose of this study was to measure the long-term growth of the mandible in miniature pigs using 3D Cone-Beam Computerized Tomography (CBCT). The mandibles of the pigs were scanned monthly over 12 months using CBCT and the 3D mandibular models were reconstructed from the data. Seventeen anatomical landmarks were identified and classified into four groups of line segments, namely anteroposterior, superoinferior, mediolateral and anteroinferior. The inter-marker distances, inter-segmental angles, volume, monthly distance changes and percentage of changes were calculated to describe mandibular growth. The total changes of inter-marker distances were normalized to the initial values. All inter-marker distances increased over time, with the greatest mean normalized total changes in the superoinferior and anteroposterior groups (p<0.05). Monthly distance changes were greatest during the first four months and then reduced over time. Percentages of inter-marker distance changes were similar among the groups, reaching half of the overall growth around the 4th month. The mandibular volume growth increased non-linearly with time, accelerating during the first five months and slowing during the remaining months. The growth of the mandible was found to be anisotropic and non-homogeneous within the bone and non-linear over time, with faster growth in the ramus than in the body. These growth patterns appeared to be related to the development of the dentition, providing necessary space for the teeth to grow upward for occlusion and for the posterior teeth to erupt.

Comparison of measurements of mandible growth using cone beam computed tomography and its synthesized cephalograms

“…[30]. Selected anatomical landmarks on the mandible were marked on the model to describe the key morphological features of the mandible (Figure 3 and Table 1).…”

ATR-FTIR Assessment of the Biochemical Composition and Micro Hardness of the Hard Tissues of Oral Cavity Submitted to Gamma Irradiation

“…Considering important to find preventive strategies in order to ensure and improve survival characteristics in the irradiated tissues and that these studies are impracticable to perform in vivo, because the ethical point of view, it must develop an in vitro protocol [14,15,[23][24][25][26][27].…”

“…The determination of effects caused by ionizing radiation, using dose for patients with head and neck cancer, in terms of variations in biochemical composition and surface microhardness [22][23][24][25][26][27][28][29][30][31], as a first step as pathophysiology comprehension, will be helpful for reduced or to eliminate inherent radiotherapy complications. Moreover, it could focus on more details from specific issues as dose reduced fractionation protocols and modalities, as long as data obtained from in vitro studies [31][32][33][34][35][36][37][38][39][40].…”

Avaliação <i>in vitro</i> da composição e microdureza dos tecidos duros da cavidade bucal submetidos à irradiação gama

“…No homem, áreas de osso haversiano são reabsorvidas mais intensamente do que osso lamelar intersticial, [16], situação que poderia acontecer no porco. Os processos metabólicos e as propriedades funcionais, assim como as densidades e características histológicas ósseas nos suínos apresentam similaridade evidenciada com respeito aos humanos, [20], [21], [22], [23] e [24].…”

“…O porco apresenta densidade óssea mineral e concentração de minerais espalhados na redes ósseas semelhantes ao osso humano, [21], [22], [23], [24] , [25].…”