Made available in DSpace on 2016-08-03T16:31:10Z (GMT). No. of bitstreams: 1 Marines Vieira Sousa.pdf: 3305948 bytes, checksum: c21aab0050594481ff5a895b6e9e86a0 (MD5) Previous issue date: 2008-02-20 / This study investigated the effects of low-intensity laser on the rate of orthodontic movement of canines submitted to initial retraction. The sample was composed of 26 maxillary and mandibular canines, submitted to initial retraction with Niti coils with an force of 150g. One canine was irradiated with diode laser according to the following protocol: 780nm/20mW/5Jcm2/0.2J per point/Et=2J, at 0, 3 and 7 days after activation; the contralateral tooth was used as placebo. Retraction was performed for 4 months in the average, adding up to 9 laser applications. Dental casts obtained at each month were digitized on a 3D Scanner (3Shape) and the three-dimensional images were analyzed on the software Geomagic Studio 5 to measure the quantity of movement of retracted canines. Statistical analysis was performed by three-way Analysis of Variance, followed by the Tukey test (p<0.05). For evaluation of tissue integrity, initial and final periapical radiographs of retracted canines and molars were obtained, to evaluate a possible alveolar crest resorption by assessment of the distance from the alveolar bone crest to the cementoenamel junction, as well as the level of root resorption by the Levander and Malmgreen index, which was evaluated only on retracted canines. The non-parametric Wilcoxon test was applied for that purpose (p<0.05). The results indicated a statistically significant increase in the rate of movement of irradiated canines compared to the contralateral teeth, at all periods, as well as maintenance of tissue integrity. Thus, it was concluded that the diode laser may accelerate the orthodontic movement, contributing to reduce the treatment time.(AU) / Este estudo investigou os efeitos do laser de baixa intensidade na velocidade da movimentação ortodôntica de caninos submetidos à retração inicial. A amostra constou de 26 caninos superiores e inferiores, submetidos à retração inicial realizada com mola Niti, com força de 150g. Um dos caninos foi irradiado com laser de diodo, seguindo o protocolo de aplicação: 780nm/20mW/5Jcm2/0,2J por ponto/Et=2J, nos dias 0, 3 e 7 pós-ativação, sendo que o contralateral foi considerado placebo. A retração durou em média 4 meses, num total de 9 aplicações de laser. Os modelos de cada mês foram escaneados com scanner 3D (3Shape) e as imagens tridimensionais foram analisadas por meio do Software Geomagic Studio 5, para a mensuração da quantidade de movimentação dos caninos retraídos. Foi empregada a Análise de Variância a três critérios, seguida pelo teste de Tukey (p<0,05). Para verificação da integridade tecidual, foram efetuadas radiografias periapicais iniciais e finais dos caninos retraídos e dos molares, nas quais foram avaliados uma possível reabsorção na crista alveolar, por meio da distância da crista óssea alveolar até a junção cemento-esmalte e os níveis de reabsorção radicular, por meio do índice de Levander e Malmgreen, sendo este último avaliado somente nos caninos retraídos. Para isto, foi empregado o teste não paramétrico de Wilcoxon (p<0,05). Os resultados indicaram que houve um aumento estatisticamente significante na velocidade da movimentação dos caninos irradiados comparados ao seu contralateral, em todos os tempos avaliados, como também a preservação da integridade tecidual. Com isso, concluiu-se que o laser de diodo pode acelerar a movimentação ortodôntica, podendo contribuir para a diminuição do tempo de tratamento.(AU)

The forces applied during orthodontic treatment will cause effects on the teeth and adjacent tissues, depending on the intensity and time of application. Changes caused in the pulp tissues are not fully clarified in the literature by the scarcity of studies, the variety of methodologies, conflicting results and difficulty in conducting research that simulate clinical situations. Given this fact, the present study aimed to evaluate the human dental pulp after application of orthodontic intrusion force through histological examination. The selected sample consisted of 34 first human premolars, with orthodontic indication of extraction, from 17 young individuals (12-19 years old, both genders). On each patient, was applied intrusion force of 60g, randomly in only one of the dental elements, forming Group-Experimental (GE). The counterpart did not receive force, constituting the Control Group (CG), characterizing a split-mouth study. After 21 days, the premolars were extracted, stored in 10% formaldehyde, submitted to histotechnical preparation and stained with hematoxylineosin. The analysis of the histological slides was carried out in optical microscopy by a single experienced calibrated examiner. The paired Fisher exact test (p ≤ 0.05), showed significant increase of fibrous tissue in the GE. The nonparametric Wilcoxon test (p ≤ 0.05), paired, showed significant increase in the number of pulpal nodules in the elements of GE and showed no difference in the number of blood vessels between the groups. In 8 elements of the GE was observed the presence of congested large caliber vessels. The orthodontic intrusion force in these conditions, caused vascular changes in the pulp tissue, increase of fibrosis and of the number of pulpal calcifications in the experimental elements. / As forças aplicadas durante o tratamento ortodôntico ocasionam efeitos nos dentes e tecidos adjacentes, conforme a intensidade e tempo de aplicação. As alterações causadas nos tecidos pulpares não estão totalmente esclarecidas na literatura pela escassez de estudos, variedade de metodologias empregadas, resultados conflitantes e dificuldade de realização de pesquisas que simulem situações clínicas. Diante desse fato, o presente estudo teve como objetivo avaliar a polpa dental humana, após a aplicação de força ortodôntica de intrusão, por meio de exame histológico. A amostra selecionada foi de 34 primeiros pré-molares humanos, com indicação ortodôntica de exodontia, de 17 indivíduos jovens (12 a 19 anos, ambos os sexos). Em cada paciente, foi aplicada força de intrusão de 60g aleatoriamente em apenas um dos elementos dentais, constituindo o Grupo- Experimental (GE). O homólogo não recebeu força constituindo o Grupo-Controle (GC), caracterizando um estudo de boca dividida. Passados 21 dias, os pré-molares foram extraídos, armazenados em formol a 10%, submetidos ao preparo histotécnico e corados com hematoxilina-eosina. A análise das lâminas histológicas foi feita em microscópio óptico, por um único examinador experiente calibrado. O teste exato de Fischer (p≤ 0,05), pareado, mostrou significativo aumento da presença de tecido fibroso no GE. O teste não-paramétrico de Wilcoxon (p≤ 0,05), pareado, mostrou significativo aumento no número de nódulos pulpares nos elementos do GE e não mostrou diferença no número de vasos sanguíneos entre os grupos. Em 8 elementos do GE foi observada a presença de vasos calibrosos e congestos. A força ortodôntica de intrusão, nessas condições, causou alterações vasculares no tecido pulpar, aumentou a presença de áreas de fibrose e o número de calcificações pulpares nos elementos experimentais.

O objetivo deste trabalho foi estudar os efeitos dos lacebacks ativos e passivos na biomecânica da fase de nivelamento, utilizando-se a técnica MBT. A amostra foi constituída de 29 sujeitos de pesquisa (22 do gênero feminino e 7 do gênero masculino), brasileiros, leucodermas e pardos, portadores de má oclusão de Classe I e com idade média de 15 anos e 5 meses. O tratamento ortodôntico foi planejado com as extrações dos primeiros pré-molares e, durante a fase estudada, foram empregados apenas fios de aço inoxidável (0.014”, 0.016”, 0.018”, 0.020” e 0.019” x 0.025”). Os recursos de ancoragem utilizados para os arcos dentários superior e inferior foram, respectivamente, o aparelho extrabucal tipo IHG e o arco lingual fixo. De acordo com a indicação dos lacebacks, a amostra foi dividida em quatro grupos: grupo I – 14 sujeitos que utilizaram lacebacks ativos no arco dentário superior; grupo II – 9 sujeitos que utilizaram lacebacks passivos no arco dentário superior; grupo III – 19 sujeitos que utilizaram lacebacks ativos no arco dentário inferior e grupo IV – 10 sujeitos que utilizaram lacebacks passivos no arco dentário inferior. Para cada indivíduo da amostra foram tomadas duas telerradiografias laterais, uma ao início e outra ao término da fase de nivelamento, com um intervalo médio de 21 meses. Os dados foram coletados utilizando-se o método cefalométrico computadorizado. Para a análise de erros, o método cefalométrico foi repetido em todos os sujeitos da amostra, pelo mesmo operador, com um intervalo mínimo de 15 dias entre as medidas. Os resultados indicaram que as variações observadas foram compatíveis com as estimativas de erros operacionais em estudos cefalométricos. Após a análise estatística e a interpretação dos resultados, verificou-se que, no grupo I, apenas a coroa do primeiro molar superior sofreu um movimento mesial e que tanto a coroa como a raiz do incisivo central superior apresentaram um movimento em direção lingual. No entanto, as inclinações destes dentes não foram alteradas. No grupo II, o primeiro molar superior se manteve estável e somente a coroa do incisivo central superior se movimentou em direção lingual, produzindo uma rotação horária deste dente. No grupo III, observou-se uma mesialização, tanto da coroa como da raiz, e extrusão do primeiro molar inferior, enquanto a posição do incisivo central inferior permaneceu inalterada. As inclinações destes dentes também não foram alteradas. No grupo IV, verificou-se que nem o primeiro molar inferior nem o incisivo central inferior apresentaram variações no sentido ântero-posterior. Verticalmente, houve extrusão apenas do primeiro molar inferior. / The purpose of this study was to evaluate the effects of active and passive lacebacks in the biomechanics of the leveling phase, using the MBT technique. The sample was composed of 29 Brazilian subjects (22 female and 7 male), Caucasian, with Class I malocclusion and mean age of 15 years and 5 months. The orthodontic treatment was planned with the extraction of the first premolars, and the leveling phase was performed with stainless steel wire only (0.014”, 0.016”, 0.018”, 0.020” e 0.019” x 0.025”). The anchorage control devices used in the upper and lower arches were, respectively, the IHG extraoral appliance and the fixed lingual arch. According to the type of laceback prescription, the sample was divided into four groups: group I – 14 subjects in which active lacebacks were used in the upper arch; group II – 9 subjects in which passive lacebacks were used in the upper arch; group III – 19 subjects in which active lacebacks were used in the lower arch; group IV – 10 subjects in which passive lacebacks were used in the lower arch. For each subject of the sample two lateral cephalometric radiographs were taken: one at the beginning and another at the end of the leveling phase, with a mean interval of 21 months. The data were collected using the resources of computerized cephalometry. To perform the analysis of errors, the cephalometric method was repeated in all subjects of the sample, by the same operator, with a minimum interval of 15 days between the measurements. The results revealed that the observed variations were compatible with the estimates of operational errors in cephalometric studies. After statistical analysis and interpretation of the results, it was observed that in group I, only the crown of the upper first molar presented a mesial movement. As to the upper central incisor, both the crown and the root presented a lingual movement. However, the inclination of these teeth was not affected. In group II, the upper first molar remained stable and only the crown of the upper central incisor moved lingually, leading to a clockwise rotation of this tooth. In group III, a mesial movement of both the crown and the root of the lower first molar was observed, along with its extrusion, whereas the position of the lower central incisor remained unchanged. The inclination of these teeth was not affected either. In group IV, it was observed that neither the lower first molar nor the lower central incisor experienced variations in the anteroposterior sense. Vertically, there only was extrusion of the lower first molar.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-14T19:54:45Z No. of bitstreams: 1 marciojosedasilvacampos.pdf: 1176643 bytes, checksum: 1457c82026f6f668987773e0e28443e4 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-29T12:17:33Z (GMT) No. of bitstreams: 1 marciojosedasilvacampos.pdf: 1176643 bytes, checksum: 1457c82026f6f668987773e0e28443e4 (MD5) / Made available in DSpace on 2017-06-29T12:17:33Z (GMT). No. of bitstreams: 1 marciojosedasilvacampos.pdf: 1176643 bytes, checksum: 1457c82026f6f668987773e0e28443e4 (MD5) Previous issue date: 2012-08-03 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Durante o tratamento ortodôntico, a densidade mineral (DM) óssea aumentada é considerada fator de risco para a reabsorção radicular apical (RRA) enquanto a DM do cemento é associada à proteção da raiz contra essa lesão. Nosso objetivo foi avaliar a DM da estrutura dentária do terço radicular apical e do osso alveolar adjacente de incisivos superiores com e sem RRA associada ao tratamento ortodôntico. Foram selecionados e submetidos ao exame de tomografia computadorizada de feixe cônico (TCFC) 21 pacientes em tratamento que apresentavam um incisivo com RRA e o seu correspondente contralateral sem RRA. A DM foi avaliada nas imagens obtidas em quatro áreas no terço apical radicular e em quatro áreas no osso alveolar adjacente. Os incisivos com RRA apresentaram DM radicular maior do que os incisivos sem RRA, porém essa diferença não foi significante. O osso alveolar supra-apical foi mais denso nos incisivos sem RRA (p<0,05). A DM radicular não foi associada com a proteção da raiz contra a reabsorção. A menor DM do osso supra-apical foi associada à presença da RRA nos incisivos superiores. / During orthodontic treatment, increased bone mineral density (BMD) is considered a risk factor for apical root resorption (ARR), whereas the cementum mineral density has been associated to the protection of the root against this lesion. Our objective was to evaluate the mineral density (MD) of the apical third of the root and adjacent alveolar bone of maxillary incisors with and without ARR associated to orthodontic treatment. Twenty one patients under treatment with one incisor with ARR and its contralateral counterpart without ARR were selected and submitted to cone beam computed tomography (CBCT). Mineral density was assessed in the images obtained from 4 areas of the apical third of the root and 4 areas of adjacent alveolar bone. Incisors with ARR showed greater root mineral density than incisors without ARR, however the difference was not significant. The supra-apical alveolar bone showed high density in the incisors without ARR (p<0.05). Root mineral density was not associated with root protection against resorption. The lower MD of the supra-apical bone was associated with the presence of ARR in the maxillary incisors.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-03-23T12:12:30Z No. of bitstreams: 1 paulamoraeslupatini.pdf: 2954241 bytes, checksum: 79130d300f2b4037e5c633836842bf06 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-03-23T12:20:52Z (GMT) No. of bitstreams: 1 paulamoraeslupatini.pdf: 2954241 bytes, checksum: 79130d300f2b4037e5c633836842bf06 (MD5) / Made available in DSpace on 2018-03-23T12:20:52Z (GMT). No. of bitstreams: 1 paulamoraeslupatini.pdf: 2954241 bytes, checksum: 79130d300f2b4037e5c633836842bf06 (MD5) Previous issue date: 2017-12-13 / Introdução: A reabsorção radicular apical (RRA) é uma conseqüência comum do tratamento ortodôntico. Sua etiologia é multifatorial, mas ainda não foi totalmente esclarecida. A análise da dimensão fractal é um método quantitativo que descreve e caracteriza a complexidade das imagens ou, mais precisamente, sua composição textural. Objetivo: O objetivo deste estudo transversal observacional foi avaliar a qualidade do tecido dentário e do osso adjacente ao terço apical radicular dos incisivos maxilares com RRA em pacientes sob tratamento ortodôntico, determinando a dimensão fractal nas imagens de tomografia computadorizada de feixe cônico e compará-las com as imagens dos dentes contralaterais correspondentes, sem RRA, no mesmo indivíduo. Metodologia: A amostra consistiu em 20 pacientes sob tratamento ortodôntico com aparelho edgewise, que apresentaram RRA em um incisivo maxilar (grupo experimental) e ausência de reabsorção no incisivo contralateral correspondente (grupo controle), identificado através de radiografias periapicais de rotina . A dimensão fractal de duas regiões no terço apical da raiz e de quatro no osso alveolar adjacente aos incisivos com RRA e seus dentes contralaterais sem RRA foi determinada e comparada. Resultados: Em todas as regiões ósseas e dentárias avaliadas, exceto no terço apical da raiz no corte coronal, os incisivos sem RRA apresentaram valores de DF maiores do que os incisivos com RRA, mas não houve diferença significativa. Conclusão: Não foi encontrada diferença estatística entre a qualidade dos tecidos radiculares e ósseos da região apical dos incisivos maxilares com e sem reabsorção apical radicular do mesmo paciente ortodôntico. / Introduction: Apical root resorption (ARR) is a common consequence of the orthodontic treatment. Its etiology is multifactorial but has not yet been entirely clarified. The fractal dimension analysis is a quantitative method that describes and caracterizes the complexity of images or, more precisely, their textural composition. Objective: The aim of this observational cross-sectional study was to assess the quality of the dental tissue and the adjacent bone of the root apical third of maxillary incisors with ARR in patients under orthodontic treatment by determining the fractal dimension in cone beam computed tomography images and compare them with the images of the corresponding contralateral teeth without ARR in the same individual. Methodology: The study sample consisted of 20 patients under orthodontic treatment with edgewise appliance, who presented apical root resorption in a maxillary incisor (experimental group) and absence of root resorption in the corresponding contralateral incisor (control group), identified through routine periapical dental radiographs. The fractal dimension of two regions in the apical third of the root and four in the adjacent alveolar bone of incisors with ARR and their contralateral teeth without ARR was determined and compared. Results: In all bone and dental regions evaluated, except the coronal slice of the apical third of the root, the incisors without ARR had higher FD values than incisors with ARR, but there was no significant difference. Conclusion: No statistical difference was found between the quality of the radicular and bone tissues of the apical region of the maxillary incisors with and without apical root resorption of the same orthodontic patient.

Indiana University-Purdue University Indianapolis (IUPUI) / The first part of the study describes the development of a microCT based engineering model to study orthodontic responses. The second part investigated the relationship between orthodontic stimulus, root resorption and bone modeling. It was hypothesized that stress magnitudes are insufficient to portray the mechanical environment and explain the clinical response; directions also play a role. An idealized tooth model was constructed for finite element analysis. The principal stress magnitudes and directions were calculated in tipping and translation. It was concluded that within the same region of root, PDL and bone, there can be compression in one structure, tension in another. At a given point in a structure, compression and tension can coexist in different directions. Magnitudes of compression or tension are typically different in different directions. Previously published data presenting only stress magnitude plots can be confusing, perhaps impossible to understand and/or correlate with biological responses. To avoid ambiguities, a reference to a principal stress should include its predominant direction. Combined stress magnitude/direction results suggest that the PDL is the initiator of mechanotransduction. The third part of this project tested the role of the P2X7 receptor in the dentoalveolar morphology of C57B/6 mice. P2X7R KO (knockout) mice were compared to C57B/6 WT to identify differences in a maxillary molar and bone. Tooth dimensions were measured and 3D bone morphometry was conducted. No statistically significant differences were found between the two mouse types. P2X7R does not have a major effect on alveolar bone or tooth morphology. The final part examines the role of the P2X7 receptor in a controlled biomechanical model. Orthodontic mechanotransduction was compared in wild-type (WT) and P2X7R knock-out (KO) mice. Using Finite Element Analysis, mouse mechanics were scaled to produce typical human stress levels. Relationships between the biological responses and the calculated stresses were statistically tested and compared. There were direct relationships between certain stress magnitudes and root resorption and bone formation. Hyalinization and root and bone resorption were different in WT and KO. Orthodontic responses are related to the principal stress patterns in the PDL and the P2X7 receptor plays a significant role in their mechanotransduction.

Indiana University-Purdue University Indianapolis (IUPUI) / Quantification of treatment outcomes (tooth displacement and bony changes) is the key to advance orthodontic research and improve clinical practices. Traditionally, treatment outcome were quantified by using two-dimensional (2D) cephalometric analysis. However, there are problems inherent in 2D analysis, such as tracing errors and inability to detect side-effects. Thus, a reliable three-dimensional (3D) image analysis method for treatment outcome quantification is of high interest. Systematic 3D image analysis methods were developed for digital dental cast models and Cone-Beam Computed Tomography (CBCT) models. A typical analysis procedure includes image reconstruction, landmarks identification, coordinate system setup, superimposition, and displacement or change calculation. The specified procedures for maxillary teeth displacements and anatomical landmarks movements were presented and validated. The validation results showed that these procedures were accurate and reliable enough for clinical applications. The 3D methods were first applied to a human canine retraction clinical study. The purposes of this study were to quantify canines and anchorage tooth movements, and to compare two commonly used canine retraction strategies, controlled tipping and translation. The canine results showed that (1) canine movements were linear with time; (2) the initial load system was not the only factor that controlled the canine movement pattern; and (3) control tipping was significantly faster than translation. The anchorage tooth results showed that (1) anchorage losses occurred even with transpalatal arch (TPA); (2) there was no significant difference in anchorage loss between the two treatment strategies; and (3) compared with removable TPA, fixed TPA appliance can significantly reduce the amount of anchorage loss in the mesial-distal direction. The second clinical application for the 3D methods was a mandibular growth clinical trial. The purposes of this study were to quantify skeletal landmark movements, and compare two widely used appliances, Herbst and MARA. The results showed that (1) the Herbst appliance caused mandibular forward movement with backward rotation; and (2) the treatment effects had no significant differences by using either Herbst or MARA appliances. The two clinical applications validated the methods developed in this study to quantify orthodontic treatment outcomes. They also demonstrated the benefits of using the 3D methods to quantify orthodontic treatment outcomes and to test fundamental hypotheses. These 3D methods can easily be extended to other clinical cases. This study will benefit orthodontic patients, clinicians and researchers.

Introduction : La vitamine D (VitD) maintient la santé osseuse et influence le mouvement dentaire orthodontique (MDO). L’objectif était d’évaluer l’effet de la VitD sur la morphométrie osseuse, puis sur la vitesse et la stabilité du MDO. Méthode : 32 rats Sprague Dawley mâles ont été assignés à deux groupes expérimentaux, traités avec la VitD par gavage (systémique) ou par injection (locale), et deux groupes contrôles respectifs traités avec un tampon phosphate salin (PBS) pour 47 jours. Le MDO était effectué pendant 7 jours avec un ressort NiTi attaché entre la première molaire supérieure et les incisives. Un scan Micro-CT était réalisé à 5 temps : T0 (avant l’administration de VitD), T1 (début du MDO), T2 (fin du MDO), T3 (7 jours post-MDO), T4 (30 jours post-MDO). La vitesse et la stabilité du MDO étaient évaluées. La morphométrie osseuse a été analysée via la densité minérale osseuse (BMD), le pourcentage de volume d’os (BV/TV), la porosité totale (Po(tot)), le facteur du patron trabéculaire (Tb.Pf), l’index de structure du modèle (SMI) et la densité de connectivité (Conn.Dn). Résultats : Le groupe VitD systémique a montré une vitesse diminuée du MDO, mais une récidive inférieure au contrôle ainsi qu’une augmentation de la BMD et du BV/TV, et une diminution de la Po(tot) (p<0.05). La structure osseuse apparaissait plus fragmentée et présentait une Conn.Dn plus basse (p<0.05). Aucune différence n’a été trouvée entre le groupe administration locale de VitD et les autres groupes. Conclusion : L’administration systémique de VitD a engendré une diminution de vitesse du MDO en induisant plus de résistance, mais a aussi contribué à une meilleure stabilité grâce à une densité osseuse plus élevée. / Introduction: Vitamin D (VitD) maintains bone health and may influence the orthodontic tooth movement (OTM). The objective was to evaluate VitD effect on bone morphometry, and on the rate and stability of OTM. Methods: 32 male Sprague Dawley rats were assigned into two experimental groups, treated with VitD by gavage (systemic) or by injection (local), and two respective control groups treated with phosphate-buffered saline (PBS) for 47 days. OTM was performed for 7 days with a NiTi coil bonded between the upper first molar and incisors. Micro-CT scanning was performed at 5 time-points: T0 (before administration of VitD), T1 (start of OTM), T2 (end of OTM), T3 (7 days post-OTM) and T4 (30 days postOTM). Rate and stability of OTM were assessed. Bone morphometry was analyzed by bone mineral density (BMD), percent bone/volume (BV/TV), total porosity (Po(tot)), trabecular pattern factor (Tb.Pf), structure model index (SMI) and connectivity density (Conn.Dn). Results: The systemic VitD group showed a lower OTM rate, but also a lower relapse than control (p<0.05). It also demonstrated an increase of BMD and BV/TV, and a decrease of Po(tot) (p<0.05). The bone structure appeared more fragmented and presented lower Conn.Dn than the control (p<0.05). No statistical difference was found between VitD local administration and the other groups for the rate and stability of OTM, or for the bone morphometry. Conclusion: The systemic administration of VitD caused a decrease of OTM rate by generating more bone resistance, but also contributed to a greater stability due to a higher bone mineral density.