Three‐Dimensional Micro‐Computed Tomographic Imaging of Alveolar Bone in Experimental Bone Loss or Repair

Park, Chan Ho; Abramson, Zachary; Taba, Mário; Jin, Qiming; Chang, Jichuan; Kreider, Jaclynn M.; Goldstein, Steven A.; Giannobile, William V.

doi:10.1902/jop.2007.060252

Cited by 187 publications

(191 citation statements)

References 26 publications

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“…Micro-computed Tomography-Mouse hemimandibles were imaged using a cone-beam micro-computed tomography (CT) system (eXplore Locus SP, Amersham Biosciences PreClinical Imaging, London, Ontario, Canada) in the Orthopaedic Research Laboratory at the University of Michigan Department of Orthopaedic Surgery, as described previously (74). In brief, hemimandibles were exposed to polychromatic x-rays on a rotating stage.…”

Section: Methodsmentioning

confidence: 99%

Hypomaturation Enamel Defects in Klk4 Knockout/LacZ Knockin Mice

Simmer

Lertlam

et al. 2009

Journal of Biological Chemistry

135

184

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Kallikrein 4 (Klk4) is believed to play an essential role in enamel biomineralization, because defects in KLK4 cause hypomaturation amelogenesis imperfecta. We used gene targeting to generate a knockin mouse that replaces the Klk4 gene sequence, starting at the translation initiation site, with a lacZ reporter gene. Correct targeting of the transgene was confirmed by Southern blot and PCR analyses. Histochemical X-gal (5-bromo-4-chloro-3-indolyl-␤-D-galactopyranoside) staining demonstrated expression of ␤-galactosidase in maturation stage ameloblasts. No X-gal staining was observed in secretory stage ameloblasts or in odontoblasts. Retained enamel proteins were observed in the maturation stage enamel of the Klk4 null mouse, but not in the Klk4 heterozygous or wild-type mice. The enamel layer in the Klk4 null mouse was normal in thickness and contained decussating enamel rods but was rapidly abraded following weaning, despite the mice being maintained on soft chow. In function the enamel readily fractured within the initial rod and interrod enamel above the parallel enamel covering the dentinoenamel junction. Despite the lack of Klk4 and the retention of enamel proteins, significant levels of crystal maturation occurred (although delayed), and the enamel achieved a mineral density in some places greater than that detected in bone and dentin. An important finding was that individual enamel crystallites of erupted teeth failed to grow together, interlock, and function as a unit. Instead, individual crystallites seemed to spill out of the enamel when fractured. These results demonstrate that Klk4 is essential for the removal of enamel proteins and the proper maturation of enamel crystals.Dental enamel is composed of highly ordered, very long crystals of calcium hydroxyapatite (Ca 10 (PO 4 ) 6 (OH) 2 ). Mature enamel crystallites are about 70 nm wide and 30 nm thick, but are of unmeasurable length (1), probably extending all the way from the dentin layer to the surface of the tooth (2). Enamel crystallites are organized into bundles called rods, with about 10,000 parallel crystals in a rod (3). Each enamel rod is the product of a single ameloblast, the cell type that forms a continuous sheet over the developing enamel and orchestrates its formation. Dental enamel of erupted teeth is ϳ95% mineral (by weight) (4), with most of the non-mineral component being water. Protein comprises Ͻ1% of its weight. Forming enamel, however, is over 30% protein (5). Much of the protein is reabsorbed by ameloblasts and degraded in lysosomes (6, 7), but extracellular proteases also play a role in matrix protein removal (8 -10).Dental enamel formation is divided into secretory, transition, and maturation stages (11,12). During the secretory stage, enamel crystals grow primarily in length. As the crystals extend, the enamel layer expands. Enamel crystallites lengthen along a mineralization front at the secretory surface of the ameloblast cell membrane. There, mineral deposits rapidly on the crystallite tips, and very slowly on their sides...

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Section: Methodsmentioning

confidence: 99%

Hypomaturation Enamel Defects in Klk4 Knockout/LacZ Knockin Mice

Simmer

Lertlam

et al. 2009

Journal of Biological Chemistry

135

184

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“…In particular, quantitative computed tomography (CT), and peripheral CT are used in humans for monitoring and treatment of metabolic diseases, skeletal status, and osteoporosis (7,8). Micro-CT yields more information about bone mass and microstructure, and is used for studies of bone metabolism in animal models (9)(10)(11). Bone formation and mineralization will affect bone strength; mechanical stability depends on the amount and density of bone (12).…”

Section: Abstract This Study Was Undertaken To Assess Bone Regeneratmentioning

confidence: 99%

Bone Regeneration of Hydroxyapatite with Granular Form or Porous Scaffold in Canine Alveolar Sockets

Jang

Kim

Han

et al. 2017

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Abstract. This study was undertaken to assess bone regeneration using hydroxyapatite (HA) Hydroxyapatite (HA) is an alloplastic material commonly used as a bone graft substitute due to inherent bioactive properties that support osteo-conduction. However, a weakness of HA-based biomaterials is their slow degradation and absorption in vivo. The granulated form of calcium phosphate ceramics has a regenerative effect within an alveolar bone defect (1). HA is highly crystalline because of the sintering process and has a larger particle size than bone apatite due to grain growth. These large particles are highly resistant to biodegradation in the body, their osteo-conduction is very low, and they cannot be degraded by osteoclasts (2). The porous HA (pHA) scaffold has good bone regeneration in in vivo performance (3-5). This form of material requires proper size and three-dimensional porosity for demonstrating its intrinsic osteo-conductivity and osteogenic potential within limited and exiguous sites such as dental sockets. An HA scaffold with interconnected pore 300 μm in diameter has the most appropriate osteo-conductive capacity (6). Therefore, we hypothesized that HA types and crystallinity influence the rate of bone healing around alveolar sockets.Bone-filling materials undergo radiological evaluation through determination of the bone mineral density (BMD) and information about bone change. Quantitative radiographic evaluation using x-rays is used to assess bone structure and mechanical properties indirectly. In particular, quantitative computed tomography (CT), and peripheral CT are used in humans for monitoring and treatment of metabolic diseases, skeletal status, and osteoporosis (7,8). Micro-CT yields more information about bone mass and microstructure, and is used for studies of bone metabolism in animal models (9-11). Bone formation and mineralization will affect bone strength; mechanical stability depends on the amount and density of bone (12).The bone-regeneration ability of each bone substitute is evaluated compared to bone metabolic disorders model by BMD, percentage bone volume, and other bone structural parameters. Our study evaluated bone substitutes in the alveolar socket of mandibles of beagle dogs to determine BMD levels by CT and bone parameter values by micro-CT at different time points.In this study, osteogenic potential was compared, focusing on alveolar socket healing and restoration using granular HA (gHA) forms and porous HA (pHA) scaffolds. Tissue engineering methods were assessed by manufacturing functional, aesthetic HAs that would not affect adjacent tooth structures. 335

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“…Measurements of the bone volume fraction (BVF) in the first molar furcation area were carried out as previously described [38]. The furcation area and root apex was chosen because they provide reproducible, morphological landmarks.…”

Section: Micro-computed Tomographymentioning

confidence: 99%