The aim of the report was to establish puncture techniques for the temporomandibular joint (TMJ) cavity in rats. The experimental sample comprised 30 male Sprague-Dawley rats. Under general anaesthesia the superior joint cavity of the rat was punctured either laterally (lateral puncture technique (LPT), n 5 11), anteriorly (anterosuperior puncture technique (ASPT), n 5 13) or anteroinferior puncture technique (AIPT), n 5 6) using a 27-gauge needle. After the tip of the needle was confirmed by micro-CT (R-mCT H , Rigaku, Tokyo, Japan) located on the mandibular fossa, 0.05 ml of contrast media was injected under micro-CT fluoroscopic guidance. After confirmation that the joint cavity was filled with contrast media, micro-CT imaging was carried out. The puncture for LPT was accurate in 5 of the 11 animals. The ASPT was accurate in all 13 animals. The AIPT punctured 3 of the 6 animals. Furthermore, the ASPT and AIPT demonstrated improved preservation of the needle; it was harder to detach the needle, which led to greater stability. These results suggest that ASPT assisted by R-mCT H is useful for basic research, including drug discovery and pathogenesis of TMJ diseases.

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Objective. The objective of this study was to compare an image-guided puncture technique (IGPT) with conventional puncture technique (CPT) with respect to accuracy of needle entry, maximal mouth opening, and pain in pumping manipulation treatment of internal derangement of the temporomandibular joint (TMJ). Study design. The subjects comprised 178 patients with internal derangement of the TMJ with closed lock. Treatment was provided using CPT in 102 cases and IGPT in 76 cases. Three variables, number of repunctures, maximal mouth opening distance, and pain threshold according to a visual analogue scale, were measured and compared between IGPT and CPT groups. Results. Access to the superior joint cavity was achieved without correcting the puncture point in 97% of patients who underwent IGPT and 82% of patients in the CPT group. Significant differences were seen in 1-week maximal mouth opening and pain threshold between IGPT and CPT groups (P Ͻ .05 each) and resetting of the puncture point was significantly less frequent using IGPT compared with CPT (P Ͻ .05).

This study aimed to show the effects of metal artifacts on the in vivo micro-CT of miniimplants by measuring bone volume. We drilled a hole in the cortical bone of a rat tibia and embedded a titanium orthodontic mini-implant (diameter, 1.5 mm) in the hole. Twelve individually weighed hydroxyapatite grains (HA grains) were placed around the implant either by one dentist (method 1) or separately by 12 dentists (method 2). In vivo micro-CT was used to scan the model after placement of each grain to measure increases and decreases in bone volume voxel number. The subtracted bone voxel volume increased with HA weight in both methods. Simple linear regression analysis showed a significant correlation between weight and volume in both methods (method 1: regression coefficient: 516.502, P < 0.05; method 2: regression coefficient: 4837.432, P < 0.05). Metal artifacts did not appear to influence measurements of bone volume, although further studies are required to determine the effect of thicker implants. (J Oral Sci 54, 55-59, 2012) Keywords: metal artifact; in vivo micro-CT; orthodontic mini-implant.

Objective of this study is to investigate whether diet or sex influences calcification of the tendon in the Mop-3/Bmal-1 gene knock-out mouse (Bmal-1 knock-out mouse) by comparing "in vivo" micro-computed tomography imaging, soft-tissue X-ray imaging, and histologic evaluation as the 'gold standard'. 23 mice were placed into 8 groups according to genetic background, diet and sex. They underwent micro-CT imaging at magnifications of ×1.5, ×4.0, and ×10.0, and soft-tissue X-ray imaging. We compared 37 tendons in each of the 8 groups that showed calcification on micro-CT ×10.0 and on histologic evaluation. On micro-CT×1.5 images, 8 of the 21 joints of Bmal-1 knock-out mice showed calcification, and calcification was seen on micro-CT×4.0 images in 19 of 21 joints, and on micro-CT ×10.0 and SOFTEX, calcifications were seen in 20 of the 21 joints. For detecting calcifications, the diagnostic accuracy of micro-CT×1.5 was 0.68, that of micro-CT ×4.0 was 0.97, that of micro-CT ×10.0 and SOFTEX was 1.00. Regarding sex and diet, calcification was seen in 5 of 5 joints from males fed a high-fat diet, 4 of 4 joints from females fed a high-fat diet, 5 of 5 joints from males fed a regular-fat diet, and 6 of 7 joints from females fed a regular-fat diet. High-speed micro-CT ×10.0 gave good diagnostic results for calcifications. Neither diet nor sex affected the appearance of the joints, whether calcified or normal. Because high-speed micro-CT is rapid and limits the animal's radiation dose, it may be an effective technique for in vivo research.