Angular immediate loading: three-dimensional finite element analysis.

OBJECTIVE: The aim of the study was to analyze the stress distribution in the bone around implants under 0, 5, 10, and 20 degrees of loading. DESIGN: Four mandible models, embedded with cylindrical implants with immediate-load angle of 0, 5, 10, and 20 degrees, were analyzed using the software ANSYS 10.0. The von Mises stress of the implant-bone interface mainly including the implant neck as well as the middle and apex areas was calculated when the implants were loaded with 200-N forces. RESULTS: Stress is mainly concentrated in the bone interface of the implant neck. With the loading implant inclining by 20 degrees, the stress concentrated in the neck of the distal side bone interface is of statistical significance (P < 0.05) when compared with the other groups; when inclined by 0 and 5 degrees, there is no statistical significance; when inclined by 10 degrees, there is statistical significance. The stress in the mesial side of the implant-bone interface is relatively small, and it has no statistical significance in each corresponding site (P > 0.05). CONCLUSIONS: The immediate load of the implant mainly increases the stress in the cortical bone around the neck of the implant. It is necessary to pay attention to the impact of the stress at the angle greater than 20 degrees or above on the implant neck; the stress in change is not obvious in the middle and apex areas of the implant as well as in the middle and apex areas of the implant under a lateral force within 20 degrees.

Association of transforming growth factor-alpha gene polymorphism and environment factors with nonsyndromic cleft lip with or without cleft palate in Han nationality / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the association of transforming growth factor-alpha (TGF-alpha gene polymorphism and environment factors with nonsyndromic cleft lip with or without cleft palate (NSCLP) in Han nationality.</p><p><b>METHODS</b>Data related to infection, drug intake and folic acid supplement during pregnancy were gained through investigation of mothers. Polymerase chain reaction combined with restrict enzyme digestion was used to detect the target gene variation in 199 patients with NSCL/P and 203 healthy controls. Analysis was carried on the genotype and infection,drug intake and folic acid supplement.</p><p><b>RESULTS</b>The C2 allele frequency in patients with NSCL/P was significantly higher than that in healthy controls. There was a significant increase of patients with NSCL/P in pregnant women exposed to infection, drug intake and folic acid deficiency. There was an interaction between C1C2 genetype and infection, drug intake and folic acid supplement.</p><p><b>CONCLUSION</b>TGF-alpha gene polymorphism is associated with NSCL/P. Infection, drug intake and folic acid supplement during pregnancy were associated with the occurrence of NSCL/P. Individuals containing C2 allele were more sensitive to infection, drug intake and folic acid deficiency.</p>

Relationship between transforming growth factor-alpha gene polymorphism and non-syndromic cleft lip with cleft palate / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the association of TGF-alpha gene polymorphism and non-syndromic cleft lip with cleft palate in Shandong province.</p><p><b>METHODS</b>Polymerase chain reaction combined with restrict enzyme digestion was used to detect the target gene variation in 98 patients with non-syndromic cleft lip with cleft palate and 101 healthy controls.</p><p><b>RESULTS</b>The C2 allele frequency in patients with non-syndromic cleft lip with cleft palate was significantly higher than that in healthy controls. The genotype frequency in patients with positive family history was significantly higher than that without positive family history.</p><p><b>CONCLUSION</b>TGF-alpha gene polymorphism is closely associated with non-syndromic cleft lip with cleft palate in Shandong, especially in patients with positive family history.</p>

Changes of mitochondrial calcium, adenosine triphosphate and adenosine diphosphate contents induced by occlusal trauma in rabbit's masseter muscles / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To study the role of Ca2+ overload and energy metabolism in mitochondria in masticatory muscle dysfunctional induced by occlusal trauma.</p><p><b>METHODS</b>Mitochondrial Ca2+ contents were measured with atomic emission spectrophotometer. Mitochondrial ATP and ADP contents were measured with high performance liquid chromatography.</p><p><b>RESULTS</b>(1) Mitochondrial Ca2+ contents of masseter muscle ipsilateral to metal splint in ten and twenty days' experimental groups and that contralateral to metal splint in twenty days' experimental group increased significantly (P < 0.05). (2) Mitochondrial ATP contents of masseter muscle ipsilateral to metal splint in experimental groups were higher than that in control groups and contralateral to metal splint after twenty days. (3) Mitochondrial Ca2+ contents of masseter muscle ipsilateral to metal splint were significantly negatively correlated to the mitochondrial ATP contents (r = -0.780, P < 0.05).</p><p><b>CONCLUSION</b>Ca2+ overload in mitochondria depresses ATP production, which results in energy metabolism disorder in masticatory muscle cells. It may play an important role in the mechanism that occlusal trauma results in masticatory muscle dysfunction.</p>