[Indirect usage of miniscrew anchorage to intrude overerupted mandibular incisors in a Class II patient with a deep overbite]. / Intérêts de l'utilisation des mini-vis orthodontiques en tant qu'ancrage indirect dans la correction de l'égression d'incisives mandibulaires pour un patient présentant une classe II hypodivergente∗.

Vertical dentoalveolar discrepancies are a common problem in orthodontic patients but are often difficult to treat with traditional mechanics. This case report illustrates the successful treatment of overerupted mandibular incisors via the indirect use of miniscrew anchorage. A woman (age, 22 years 9 months) had chief complaints of maxillary incisor protrusion and crooked teeth. An excessive curve of Spee caused by elongation of the mandibular incisors was also found. The patient was diagnosed with a severe Class II Division 1 malocclusion and a deep overbite. After extraction of the mandibular first premolars and the subsequent leveling phase, the elongated incisors were intruded with a novel method, which involved the combined use of sectional archwires and miniscrews placed in the premolar areas. After the procedure, the mandibular incisors had been intruded by 6.5 mm with no undesirable side effects. The total active treatment period was 42 months. The resultant occlusion and satisfactory facial profile were maintained after 30 months of retention. Our novel intrusion approach shows potential for correcting a deep overbite.

Indirect usage of miniscrew anchorage to intrude overerupted mandibular incisors in a Class II patient with a deep overbite.

Vertical dentoalveolar discrepancies are a common problem in orthodontic patients but are often difficult to treat with traditional mechanics. This case report illustrates the successful treatment of overerupted mandibular incisors via the indirect use of miniscrew anchorage. A woman (age, 22 years 9 months) had chief complaints of maxillary incisor protrusion and crooked teeth. An excessive curve of Spee caused by elongation of the mandibular incisors was also found. The patient was diagnosed with a severe Class II Division 1 malocclusion and a deep overbite. After extraction of the mandibular first premolars and the subsequent leveling phase, the elongated incisors were intruded with a novel method, which involved the combined use of sectional archwires and miniscrews placed in the premolar areas. After the procedure, the mandibular incisors had been intruded by 6.5 mm with no undesirable side effects. The total active treatment period was 42 months. The resultant occlusion and satisfactory facial profile were maintained after 30 months of retention. Our novel intrusion approach shows potential for correcting a deep overbite.

Ex vivo real-time observation of Ca(2+) signaling in living bone in response to shear stress applied on the bone surface.

Bone cells respond to mechanical stimuli by producing a variety of biological signals, and one of the earliest events is intracellular calcium ([Ca(2+)](i)) mobilization. Our recently developed ex vivo live [Ca(2+)](i) imaging system revealed that bone cells in intact bone explants showed autonomous [Ca(2+)](i) oscillations, and osteocytes specifically modulated these oscillations through gap junctions. However, the behavior and connectivity of the [Ca(2+)](i) signaling networks in mechanotransduction have not been investigated in intact bone. We herein introduce a novel fluid-flow platform for probing cellular signaling networks in live intact bone, which allows the application of capillary-driven flow just on the bone explant surface while performing real-time fluorogenic monitoring of the [Ca(2+)](i) changes. In response to the flow, the percentage of responsive cells was increased in both osteoblasts and osteocytes, together with upregulation of c-fos expression in the explants. However, enhancement of the peak relative fluorescence intensity was not evident. Treatment with 18 α-GA, a reversible inhibitor of gap junction, significantly blocked the [Ca(2+)](i) responsiveness in osteocytes without exerting any major effect in osteoblasts. On the contrary, such treatment significantly decreased the flow-activated oscillatory response frequency in both osteoblasts and osteocytes. The stretch-activated membrane channel, when blocked by Gd(3+), is less affected in the flow-induced [Ca(2+)](i) response. These findings indicated that flow-induced mechanical stimuli accompanied the activation of the autonomous [Ca(2+)](i) oscillations in both osteoblasts and osteocytes via gap junction-mediated cell-cell communication and hemichannel. Although how the bone sense the mechanical stimuli in vivo still needs to be elucidated, the present study suggests that cell-cell signaling via augmented gap junction and hemichannel-mediated [Ca(2+)](i) mobilization could be involved as an early signaling event in mechanotransduction.

Bone morphogenetic protein 3 expression pattern in rat condylar cartilage, femoral cartilage and mandibular fracture callus.

Mandibular condylar cartilage differs from primary cartilage in morphological organization of the chondrocytes and in responses to biomechanical stress and humoral factors. For the first time, we describe the expression of Bmp3 mRNA in relation to types I, II and X collagen mRNA (as determined by in situ hybridization) in chondrocytes of the rat mandibular condylar cartilage, femoral articular cartilage, femoral growth plate cartilage, and temporal cartilage, which transiently appeared in the reparative response stage of mandibular ramus fracture healing. In all cartilages evaluated, Bmp3 was expressed in proliferating chondrocytes that expressed type I collagen in condylar cartilage, articular cartilage, and temporal cartilage appearing during fracture healing. Bmp3 was also found in hypertrophic chondrocytes that expressed type X collagen mRNA in all cartilages evaluated. Furthermore, in remodeling bone, Bmp3 mRNA was strongly expressed in active osteoblast cells in periosteal reaction layers formed after fracture. These findings suggest that Bmp3 expression in a special layer of typical articular cartilage may be regulated by mechanical stress stimulation. We also found that Bmp3 was expressed in the periosteal layers of the bone segments near the fracture site during fracture healing.

Experimental tooth movement upregulates preproenkephalin mRNA in the rat trigeminal nucleus caudalis and oralis.

Levels of preproenkephalin mRNA expression in trigeminal subnucleus complex by noxious tooth movement stimuli were examined using in situ hybridization. At 24 h, preproenkephalin mRNA expression was significantly upregulated in the ipsilateral trigeminal subnucleus caudalis (P<0.05), and in the subnucleus oralis (P<0.05). These findings suggested that enkephalinergic inhibitory systems could be activated during tooth movement, and that subnucleus oralis may be involved in modulation of the nociception, as well as the subnucleus caudalis.