Occlusal reconstruction of a patient with ameloblastoma ablation using alveolar distraction osteogenesis: a case report

Background Ameloblastoma is one of the most common benign odontogenic neoplasms. Its surgical excision has the potential to lead to postoperative malocclusion. In this case report, we describe the successful interdisciplinary orthodontic treatment of a patient with ameloblastoma who underwent marginal mandibulectomy. Case presentation A woman of 20-year-old was diagnosed with ameloblastoma, and underwent marginal mandibulectomy when she was 8 years of age. She had an excessive overjet (11.5 mm) and a mild open bite (- 1.5 mm) with a severely resorbed atrophic edentulous ridge in the area around the mandibular left lateral incisor, canine and first premolar. An alveolar bone defect associated with tumor resection was regenerated by vertical distraction osteogenesis (DO). Subsequently, 3 dental implants were placed into the reconstructed mandible. Orthodontic treatment using implant-anchored mechanics provided a proper facial profile with significantly improved occlusal function. The occlusion appeared stable for a 7-year retention period. Conclusions These results suggest that surgically assisted and implant anchored-orthodontic approaches might be effective for the correction of such malocclusions

Newly developed data-matching methodology for oral implant surgery allowing the automatic deletion of metal artifacts in 3D-CT images using new reference markers: A case report

Patients: The patient was a 55-year-old woman with left upper molar free-end edentulism and 9 full cast metal crowns in her mouth. Three three-dimensional (3D) images were superimposed: a computed tomography (CT) image with the patient wearing the CT-matching template (CTMT) with six glass ceramic markers, which hardly generate any artifacts, on the template surface, and oral plaster model surfaces with and without CTMTs. Metal artifacts were automatically removed by a Boolean operation identifying unrealistic images outside the oral plaster model surface. After the preoperative simulation, fully guided oral implant surgery was performed. Two implant bodies were placed in the left upper edentulism. The placement errors calculated by comparing the preoperative simulation and actual implant placement were then assessed by a software program using the 3D-CT bone morphology as a reference. The 3D deviations between the preoperative simulation and actual placement at the entry of the implant body were a maximum 0.48 mm and minimum 0.26 mm. Those at the tip of the implant body were a maximum 0.56 mm and a minimum 0.25 mm. Discussion: In this case, the maximum 3D deviations at the entry and tip section were less than in previous studies using double CT. Conclusions: Accurate image fusion utilizing CTMT with new reference markers was possible for a patient with many metal restorations. Using a surgical guide manufactured by the new matching methodology (modified single CT scan method), implant placement deviation can be minimized in patients with many metal restorations

A dehydrated space-weathered skin cloaking the hydrated interior of Ryugu

Without a protective atmosphere, space-exposed surfaces of airless Solar System bodies gradually experience an alteration in composition, structure and optical properties through a collective process called space weathering. The return of samples from near-Earth asteroid (162173) Ryugu by Hayabusa2 provides the first opportunity for laboratory study of space-weathering signatures on the most abundant type of inner solar system body: a C-type asteroid, composed of materials largely unchanged since the formation of the Solar System. Weathered Ryugu grains show areas of surface amorphization and partial melting of phyllosilicates, in which reduction from Fe3+ to Fe2+ and dehydration developed. Space weathering probably contributed to dehydration by dehydroxylation of Ryugu surface phyllosilicates that had already lost interlayer water molecules and to weakening of the 2.7 µm hydroxyl (–OH) band in reflectance spectra. For C-type asteroids in general, this indicates that a weak 2.7 µm band can signify space-weathering-induced surface dehydration, rather than bulk volatile loss

The effect of growth factors for bone augmentation to enable dental implant placement: A systematic review

This systematic review assessed the potential benefits of growth factors for bone augmentation prior to the placement of dental implants in human. A systematic online review of the Medline database, using the PubMed search machine was performed between 1966 and November 2008 by entering the MeSH terms. The primary outcome of the included studies was bone regeneration of localized alveolar ridge defects. The initial search identified 119 papers from the electronic database. This review produced seven eligible papers that reported on bone augmentation with recombinant human Bone Morphogenetic Protein-2 (rhBMP-2), recombinant human Platelet-Derived Growth Factor (rhPDGF) and Plasma-Rich Growth Factor (PRGF). The rhBMP-2 affected local bone augmentation with increasing volume for higher doses. Both rhPDGF and PRGF showed a positive effect in favor of the growth factor. Differing levels and quantity of evidence were noted to be available for the growth factors evaluated, revealing that rhBMP-2, rhPDGF, and PRGF may stimulate local bone augmentation to various conditions. Especially the potential of rhBMP-2 is supportive. However, the confined number of investigators using these techniques and the low number of patient treatments reported in the literature, the generalizability of this approach is limited at this time

A Methyl Viologen-Resistant Mutant of Arabidopsis, Which Is Allelic to Ozone-Sensitive rcd1, Is Tolerant to Supplemental Ultraviolet-B Irradiation

To better understand the role of active oxygen species (AOS) in acquired resistance to increased levels of ultraviolet (UV)-B irradiation in plants, we isolated an Arabidopsis mutant that is resistant to methyl viologen, and its sensitivity to UV-B was investigated. A complementation test revealed that the obtained mutant was allelic to the ozone-sensitive radical-induced cell death1-1 (rcd1-1). Therefore, this mutant was named rcd1-2. rcd1-2 was recessive and nearly 4-fold more resistant to methyl viologen than wild type. It exhibited a higher tolerance to short-term UV-B supplementation treatments than the wild type: UV-B-induced formation of cyclobutane pyrimidine dimers was reduced by one-half after 24 h of exposure; the decrease in quantum yield of photosystem II was also diminished by 40% after 12 h of treatment. Furthermore, rcd1-2 was tolerant to freezing. Steady-state mRNA levels of plastidic Cu/Zn superoxide dismutase and stromal ascorbate peroxidase were higher in rcd1-2 than in wild type, and the mRNA level of the latter enzyme was enhanced by UV-B exposure more effectively in rcd1-2. UV-B-absorbing compounds were more accumulated in rcd1-2 than in wild type after UV-B exposure for 24 h. These findings suggest that rcd1-2 methyl viologen resistance is due to the enhanced activities of the AOS-scavenging enzymes in chloroplasts and that the acquired tolerance to the short-term UV-B exposure results from a higher accumulation of sunscreen pigments. rcd1 appears to be a mutant that constitutively shows stress responses, leading to accumulation of more pigments and AOS-scavenging enzymes without any stresses

Puffer smells tetrodotoxin

Behavioral observation was conducted to test whether olfaction is functional to detect tetrodotoxin (TTX) in tiger puffer Takifugu rubripes using Y-maze. We placed either agarose carrier or one agarose and one agarose containing TTX (200 MU) at each head of the channel of Y-maze. Then three non-toxic hatchery-reared juveniles (body length, 5.6 ± 0.4 cm; n = 18) were released into the Y-maze and pecking behavior to carrier was observed for 3 h. The same procedure was tested for olfactory-ablated juveniles and for juveniles taht received sham operation. Juveniles showed significant selectivity to TTX, except for olfactory-ablated juveniles. These results indicate that pufferfish detects TTX by olfactory organ