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Effects of Decreased Occlusal Loading during Growth on the Mandibular Bone Characteristics.

Hichijo N, Tanaka E, Kawai N, van Ruijven LJ, Langenbach GE - PLoS ONE (2015)

Bottom Line: Mandibular mineralization patterns were very consistent, showing a lower degree of mineralization in the ramus than in the corpus.However, these changes are very region-specific, probably depending on the alterations in the local loading regime.The results suggest that muscle activity during growth is very important for bone quality and morphology.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences, Tokushima, Japan.

ABSTRACT

Background: Bone mass and mineralization are largely influenced by loading. The purpose of this study was to evaluate the reaction of the entire mandibular bone in response to decreased load during growth. It is hypothesized that decreased muscular loading will lead to bone changes as seen during disuse, i.e. loss of bone mass.

Methods and findings: Ten 21-day-old Wistar strain male rats were divided into two groups (each n=5) and fed on either a hard- or soft-diet for 11 weeks. Micro-computed tomography was used for the investigation of bone mineralization, bone volume, bone volume fraction (BV/TV) and morphological analysis. Mandibular mineralization patterns were very consistent, showing a lower degree of mineralization in the ramus than in the corpus. In the soft-diet group, mineralization below the molars was significantly increased (p<0.05) compared to the hard diet group. Also, bone volume and BV/TV of the condyle and the masseter attachment were decreased in the soft-diet group (p<0.05). Morphological analysis showed inhibited growth of the ramus in the soft-diet group (p<0.05).

Conclusion: Decreased loading by a soft diet causes significant changes in the mandible. However, these changes are very region-specific, probably depending on the alterations in the local loading regime. The results suggest that muscle activity during growth is very important for bone quality and morphology.

No MeSH data available.


Related in: MedlinePlus

Graphs depicting the material mineralization of the cortex at the (A) Condyle, (B) Attachment of the masseter, (C) The part below the second tooth.**Significant difference between both groups (p<0.05).
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pone.0129290.g004: Graphs depicting the material mineralization of the cortex at the (A) Condyle, (B) Attachment of the masseter, (C) The part below the second tooth.**Significant difference between both groups (p<0.05).

Mentions: Mineralization maps of the mandibles (Fig 3A and 3B) showed a remarkably similar distribution pattern of mineralization. Also, both groups showed very similar values and patterns in the regions of the condyle and the muscle attachments (Fig 4). However, below the dentition a significantly higher (p = 0.003) regional mineralization (material density) was found in the soft-diet group (1300 mg HA) compared to the hard-diet group (1200 mg HA) (Fig 4C).


Effects of Decreased Occlusal Loading during Growth on the Mandibular Bone Characteristics.

Hichijo N, Tanaka E, Kawai N, van Ruijven LJ, Langenbach GE - PLoS ONE (2015)

Graphs depicting the material mineralization of the cortex at the (A) Condyle, (B) Attachment of the masseter, (C) The part below the second tooth.**Significant difference between both groups (p<0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4465670&req=5

pone.0129290.g004: Graphs depicting the material mineralization of the cortex at the (A) Condyle, (B) Attachment of the masseter, (C) The part below the second tooth.**Significant difference between both groups (p<0.05).
Mentions: Mineralization maps of the mandibles (Fig 3A and 3B) showed a remarkably similar distribution pattern of mineralization. Also, both groups showed very similar values and patterns in the regions of the condyle and the muscle attachments (Fig 4). However, below the dentition a significantly higher (p = 0.003) regional mineralization (material density) was found in the soft-diet group (1300 mg HA) compared to the hard-diet group (1200 mg HA) (Fig 4C).

Bottom Line: Mandibular mineralization patterns were very consistent, showing a lower degree of mineralization in the ramus than in the corpus.However, these changes are very region-specific, probably depending on the alterations in the local loading regime.The results suggest that muscle activity during growth is very important for bone quality and morphology.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthodontics and Dentofacial Orthopedics, Tokushima University Graduate School of Oral Sciences, Tokushima, Japan.

ABSTRACT

Background: Bone mass and mineralization are largely influenced by loading. The purpose of this study was to evaluate the reaction of the entire mandibular bone in response to decreased load during growth. It is hypothesized that decreased muscular loading will lead to bone changes as seen during disuse, i.e. loss of bone mass.

Methods and findings: Ten 21-day-old Wistar strain male rats were divided into two groups (each n=5) and fed on either a hard- or soft-diet for 11 weeks. Micro-computed tomography was used for the investigation of bone mineralization, bone volume, bone volume fraction (BV/TV) and morphological analysis. Mandibular mineralization patterns were very consistent, showing a lower degree of mineralization in the ramus than in the corpus. In the soft-diet group, mineralization below the molars was significantly increased (p<0.05) compared to the hard diet group. Also, bone volume and BV/TV of the condyle and the masseter attachment were decreased in the soft-diet group (p<0.05). Morphological analysis showed inhibited growth of the ramus in the soft-diet group (p<0.05).

Conclusion: Decreased loading by a soft diet causes significant changes in the mandible. However, these changes are very region-specific, probably depending on the alterations in the local loading regime. The results suggest that muscle activity during growth is very important for bone quality and morphology.

No MeSH data available.


Related in: MedlinePlus