Trehalose biosynthetic gene otsB of Corynebacterium glutamicum is regulated by whcE in response to oxidative stress.

The gene whcE of Corynebacterium glutamicum plays a positive role in oxidative stress responses and the WhcE protein interacts with SpiE. By utilizing 2D-PAGE analysis, we identified the otsB gene to be under the control of whcE. The transcription of otsB, encoding trehalose 6-phosphatase, was stimulated by oxidative stress, and whcE and spiE were involved in diamide-mediated transcriptional stimulation. The ΔotsB strain was created and found to be sensitive to the thiol-specific oxidant diamide, suggesting a role of the gene in stress responses. Genes located upstream of otsB, such as NCgl2534 and otsA, formed an operon and purified WhcE was able to bind to the promoter region of the operon (PNCgl2534), but the binding was only possible in the presence of the oxidant diamide. In addition, the transcriptional activation of PNCgl2534 by WhcE was demonstrated in in vivo assays and the transcription was stimulated in cells exposed to the oxidant diamide. These findings indicate that WhcE is a transcriptional activator, and otsB, which is involved in trehalose biosynthesis, has a role in oxidative stress responses in C. glutamicum.

Late implant placement following ridge preservation versus early implant placement: A pilot randomized clinical trial for periodontally compromised non-molar extraction sites.

AIM: To compare late implant placement following alveolar ridge preservation (LP/ARP) and early implantation (EP) in periodontally compromised non-molar extraction sites with respect to soft tissue levels, aesthetics, and patient-reported outcomes. MATERIALS AND METHODS: Sixteen patients were randomly allocated to groups LP/ARP (n = 9) or EP (n = 7). Group LP/ARP received ARP using deproteinized bovine bone mineral containing 10% collagen and a native bilayer collagen membrane, and group EP received only extraction. Implant placement was performed 4-8 weeks post-extraction in group EP and 4 months post-alveolar ridge preservation in group LP/ARP. The soft tissue levels, pink/white esthetic scores, and periodontal parameters were evaluated at 1 year post-loading. Patient's discomfort level was evaluated in terms of extraction/ARP and implant placement. RESULTS: No implant failure or biologic complications occurred. There was no statistically significant difference in the median change of the midfacial mucosal margin (0.03 for group LP/ARP, -0.19 mm for group EP) and the mesial/distal papilla (0.62/0.25 mm for group LP/ARP, 0.29/-0.5 mm for group EP), pink/white esthetic scores, periodontal parameters, and patient's discomfort between the two groups. CONCLUSION: Both implant placement protocols led to comparable outcomes in soft tissue levels, periodontal parameters, and patient's discomfort level.

Self-emitting blue and red EuOX (X = F, Cl, Br, I) materials: band structure, charge transfer energy, and emission energy.

Self-emitting blue and red EuOX (X = F, Cl, Br, and I) were successfully synthesized and characterized. Far-infrared and Raman measurements revealed that the vibration modes prominently reflected the Eu-O and Eu-X bond characters of these materials. X-ray photoelectron spectroscopy (XPS) of the red-emitting EuOX compounds showed that Eu exclusively existed as Eu3+, while in the blue-emitting EuOX, a mixed Eu3+/Eu2+ state was observed. For the red-emitting EuOX (X = F, Cl, and Br), the maximum wavelengths of the charge-transfer (CT) bands were red-shifted: F → Cl → Br (282, 320, and 330 nm for F, Cl, and Br, respectively). Using one-electron spin-polarized band structure calculations, it was verified that the red-shift of the CT energy from F to Br in EuOX was mainly due to the relative positions of the halogen orbital energies being gradually increased, following the trend in their electronegativity. For the blue-emitting EuOX (X = Cl, Br, and I), the emission band maxima were red-shifted from Cl to I (409, 414, and 432 nm for Cl, Br, and I, respectively), which was quite opposite to the trend predicted based on the spectrochemical series in crystal field theory, which was in good agreement with the previous results of the calculated 5d → 4f transition energies of the Eu2+ activator based on the crystal field theory. Through photoluminescence, UV-visible absorbance, and XPS, it was elucidated that the red emission due to Eu3+ was strongly masked by the intensified blue emission associated with the small amount of Eu2+ in the blue-emitting EuOX (X = Cl, Br, and I). These materials may provide a platform for modeling new phosphors for application in solid-state lighting.

Ridge preservation in molar extraction sites with an open-healing approach: A randomized controlled clinical trial.

AIM: To determine the effect of alveolar ridge preservation (ARP) in molar sites without primary flap closure. MATERIALS AND METHODS: Three groups were established: extraction sockets grafted with deproteinized bovine bone mineral containing 10% collagen (DBBM-C) and covered by a native bilayer collagen membrane (NBCM) (test group 1), sockets grafted with DBBM-C only (test group 2), and sockets that healed naturally (control group). Primary flap closure was not attempted. Conebeam computed tomography scans were obtained immediately and then 4 months after ARP. A biopsy was performed. The change of the marginal bone level was measured. RESULTS: There was significantly less horizontal resorption in test group 1 than in the control group at levels 1 mm (-1.02 ± 0.88 [mean ± SD] vs. -4.44 ± 3.71 mm) and 3 mm (-0.31 ± 1.51 vs. -2.27 ± 1.15 mm) below the crest, and significantly less vertical reduction in the midcrestal area in test group 1 than in test group 2 (-0.25 ± 0.95 vs. -1.15 ± 1.63 mm) (p < .05). There were no significant differences between test groups in clinical and histomorphometric measurements. All groups exhibited stable marginal bone levels after 1 year of loading. CONCLUSION: Alveolar ridge preservation without primary flap closure in molar areas was effective in minimizing ridge resorption and facilitated implant treatment.

A randomized, double-blind, placebo-controlled multicenter study for evaluating the effects of fixed-dose combinations of vitamin C, vitamin E, lysozyme, and carbazochrome on gingival inflammation in chronic periodontitis patients.

BACKGROUND: To evaluate gingival inflammation from fixed-dose combinations of vitamin C, vitamin E, lysozyme and carbazochrome (CELC) in the treatment of chronic periodontitis following scaling and root planing. METHODS: One hundred patients were randomly assigned to receive CELC (test) or placebo (control) for the first 4 weeks at a 1:1 ratio, and both groups received CELC for the remaining 4 weeks. Primary outcome was the mean change in the gingival index (GI) after 4 weeks. Secondary outcomes included mean change in GI after 8 weeks and plaque index, probing depth, clinical attachment level, and VAS at 4 weeks and 8 weeks. RESULTS: Ninety-three patients completed the study. The GI in the test group significantly decreased after 4 weeks (p < 0.001) and 8 weeks (p < 0.001). The mean change from baseline in GI significantly decreased in the test group compared to the control group after 4 weeks (p = 0.015). In the GEE model adjusting for age, gender and visits, the test group showed 2.5 times GI improvement compared to the control group (p = 0.022). CONCLUSIONS: Within the study, CELC showed a significant reduction in gingival inflammation compared with a placebo. Other parameters, however, were similar between groups. TRIAL REGISTRATION: KCT0001366 (Clinical Research Information Service, Republic of Korea) and 29 Jan 2015, retrospectively registered.

Description of the periodontal pocket in preclinical models: limitations and considerations.

Establishment of periodontal health and regeneration of the lost periodontal tissues are always the ultimate goal of periodontal treatment. The development of new therapeutic approaches raises the necessity for appropriate experimental models that present periodontal structures and healing capability comparable to humans. Preclinical research and extrapolation of the data to human conditions remains a stage of great importance before the clinical application of the new biomaterials and techniques. Periodontal pockets/defects in preclinical models can be induced experimentally through acute or chronic or a combination of both (induced) modalities. The features of the created defects and those of humans vary greatly mostly due to the nature of the periodontal disease. This is an important point to take into account, since it is well recognized that the potential of periodontal therapy may be dependent on both the biological background and the defect morphology. This review provides insight into the commonly used preclinical models for the reproduction of the periodontal pocket and discusses the advantages and disadvantages of each model in terms of similarity to human conditions, standardization and reproducibility.

Highly Luminous and Thermally Stable Mg-Substituted Ca2-xMgxSiO4:Ce (0 ≤ x ≤ 1) Phosphor for NUV-LEDs.

Blue-emitting Ca2-xMgxSiO4:Ce (0.0 ≤ x ≤ 1.0) phosphors were successfully synthesized and characterized. Rietveld refinement revealed that four main phases exist within the solid-solution range of CaO-MgO-SiO2, namely, ß-Ca2SiO4 (Mg (x) = 0.0), Ca14Mg2(SiO4)8 (Mg (x) = 0.25), Ca3Mg(SiO4)2 (Mg (x) = 0.5), and CaMgSiO4 (Mg (x) = 1.0). The variation of the IR modes was more prominent with increasing Mg2+ content in the Ca2-xMgxSiO4 materials. The sharing of O atoms of the SiO4-tetrahedra by the MgO6-octahedra induced weakening of the Si-O bonds, which resulted in the red shift of the [SiO4] internal modes and appearance of a Mg-O stretching vibration at ∼418 cm-1. Raman measurement revealed that the change of the Ca-O bond lengths because of the Mg2+-substitution directly reflected the frequency shift of the Si-O stretching-Raman modes. Notably, the thermal stability of Ca2-xMgxSiO4:Ce (Mg (x) > 0.0) phosphors was superior to that of ß-Ca2SiO4:Ce (Mg (x) = 0.0) as confirmed by temperature-dependent photoluminescence (PL) measurements. This indicated that Mg2+ ions play an important role in enhancement of the thermal stability. In combination with the results from PL and electroluminescence (EL), it was elucidated that the luminous efficiency of Ca2-xMgxSiO4:Ce (Mg (x) = 0.1) was approximately twice as much as ß-Ca2SiO4:Ce (Mg (x) = 0.00), directly indicating a "Mg2+-substitution effect". The large enhancements of PL, EL, and thermal stability because of Mg2+-substitution may provide a platform in the discovery of more efficient phosphors for NUV-LEDs.

Long-term outcomes of dental implants placed in elderly patients: a retrospective clinical and radiographic analysis.

OBJECTIVES: The aim of this retrospective study was to determine the clinical and the radiographic outcomes of dental implants placed in elderly people older than 65 years. MATERIALS AND METHODS: In total, 902 implants in 346 patients (age: 65-89 years) were followed up for 2-17 years following the implant surgery. The survival rate of these implants was recorded and analyzed. Changes in marginal bone levels were also analyzed in serial radiographs, and Cox regression analysis for implant loss was performed. RESULTS: The survival rates were 95.39% and 99.98% in the implant- and patient-based analyses, respectively (involving a total of 29 implant failures), and the marginal bone loss at the implants was 0.17 ± 0.71 mm (mean ± SD). The number of failures was greatest in patients aged 65-69 years. The Cox regression with shared frailty analysis showed that implant loss was significantly greater in those aged 65-69 years than in those aged 70-74 years (P < 0.05), and it varied between specific implant systems. CONCLUSIONS: Within the limitations of this retrospective study, it was concluded that implant therapy can be successfully provided to elderly patients and that age alone does not seem to affect the implant survival rate.

Eu(2+)-Activated Alkaline-Earth Halophosphates, M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) for NUV-LEDs: Site-Selective Crystal Field Effect.

Eu(2+)-activated M5(PO4)3X (M = Ca, Sr, Ba; X = F, Cl, Br) compounds providing different alkaline-earth metal and halide ions were successfully synthesized and characterized. The emission peak maxima of the M5(PO4)3Cl:Eu(2+) (M = Ca, Sr, Ba) compounds were blue-shifted from Ca to Ba (454 nm for Ca, 444 nm for Sr, and 434 nm for Ba), and those of the Sr5(PO4)3X:Eu(2+) (X = F, Cl, Br) compounds were red-shifted along the series of halides, F → Cl → Br (437 nm for F, 444 nm for Cl, and 448 nm for Br). The site selectivity and occupancy of the activator ions (Eu(2+)) in the M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) crystal lattices were estimated based on theoretical calculation of the 5d → 4f transition energies of Eu(2+) using LCAO. In combination with the photoluminescence measurements and theoretical calculation, it was elucidated that the Eu(2+) ions preferably enter the fully oxygen-coordinated sites in the M5(PO4)3X:Eu(2+) (M = Ca, Sr, Ba; X = F, Cl, Br) compounds. This trend can be well explained by "Pauling's rules". These compounds may provide a platform for modeling a new phosphor and application in the solid-state lighting field.

SpiE interacts with Corynebacterium glutamicum WhcE and is involved in heat and oxidative stress responses.

The gene whcE in Corynebacterium glutamicum positively responds to oxidative and heat stress. To search for proteins that interact with WhcE, we employed a two-hybrid system with WhcE as the bait. Sequencing analysis of the isolated clones revealed peptide sequences, one of which showed high sequence identity to a hydrophobe/amphiphile efflux-1 family transporter encoded by NCgl1497. The interaction of the NCgl1497-encoded protein with WhcE in vivo was verified using reporter gene expression by real-time quantitative PCR (RT-qPCR). The WhcE protein strongly interacted with the NCgl1497-encoded protein in the presence of oxidative and heat stress. Furthermore, purified WhcE and NCgl1497-encoded proteins interacted in vitro, especially in the presence of the oxidant diamide, and the protein-protein interaction was disrupted in the presence of the reductant dithiothreitol. In addition, the transcription of NCgl1497 was activated approximately twofold in diamide- or heat-treated cells. To elucidate the function of the NCgl497 gene, an NCgl1497-deleted mutant strain was constructed. The mutant showed decreased viability in the presence of diamide and heat stress. The mutant strain also exhibited reduced transcription of the thioredoxin reductase gene, which is known to be regulated by whcE. Based on the results, NCgl1497 was named spiE (stress protein interacting with WhcE). Collectively, our data suggest that spiE is involved in the whcE-mediated oxidative stress response pathway of C. glutamicum.

A systematic review on the correlation between skeletal and jawbone mineral density in osteoporotic subjects.

OBJECTIVES: The aim of this systematic review was to assess whether the systemic skeletal reduction of bone mineral density (BMD) that characterizes osteoporotic subjects is also associated with a reduction of BMD in the jawbones. MATERIAL AND METHODS: Two reviewers searched independently and in duplicate three databases up to May 2014 and assessed the risk of bias using a tailored version of the Newcastle-Ottawa scale (NOS). Only papers reporting either Pearson's correlation coefficient or Spearman's rank correlation coefficient between skeletal and jawbone mineral density in more than five osteoporotic subjects were selected. RESULTS: From 1763 citations, 64 full-text papers were screened and five papers that met the inclusion criteria were included in the final analysis. None of the included studies complied with all NOS criteria, and as only two studies were eligible for meta-analysis, this was not performed. CONCLUSIONS: Only limited conclusions can be drawn from this systematic review, due to the small number of studies included, their heterogeneity, and their high risk of bias. Future studies that take into consideration both upper and lower jaws, that use the same technique to measure skeletal and jaw BMD (ideally dual-energy X-ray absorptiometry, DXA), and that account for confounding variables (such as medications/diseases affecting bone metabolism and demographics) are needed to provide more robust conclusions.

Luminescent properties of rare earth fully activated apatites, LiRE9(SiO4)6O2 (RE = Ce, Eu, and Tb): site selective crystal field effect.

Novel LiCe9(SiO4)6O2 and LiTb9(SiO4)6O2 compounds have been successfully synthesized, and the site selectivity and occupancy of activator ions have been estimated including LiEu9(SiO4)6O2 compound. The rare earth (RE) fully occupied compounds, as well as the RE partially occupied congeners are required for the assessment of site selectivity of RE (activator) ions in apatite-type compounds. The splitting energies of the 6H and 4F Wycoff positions of LiRE9(SiO4)6O2 (RE = Ce, Eu, and Tb) compounds are calculated based on crystal field theory: ΔECe(6H) = 3849.3 cm(-1), ΔECe(4F) = 4228.1 cm(-1), ΔEEu(6H) = 3870.0 cm(-1), ΔEEu(4F) = 4092.8 cm(-1), ΔETb(6H) = 3637.6 cm(-1), ΔETb(4F) = 4396.1 cm(-1), indicating that the splitting energy for the 4F site is larger than that for the 6H site in all compounds; thus the absorption energy is higher for the 6H site. In apatite-type LiRE9(SiO4)6O2 (RE = Ce, Eu, and Tb) compounds, the Ce(3+) ions predominantly occupy the 4F site associated with the absorption band around 300 nm at lower Ce(3+) concentration, and then enter the 6H site associated the absorption band around 245 nm. For the Eu(3+)-doped compounds, the 4F site and 6H site are mixed within the charge transfer band (CTB) between 220 and 350 nm. Eu(3+) ions initially preferentially occupy the 6H site (around 290 nm) at lower Eu(3+) concentration and subsequently enter the 4F site (around 320 nm) with increasing Eu(3+) concentration. For the Tb(3+)-doped compounds, the absorption due to the two different sites is mixed within f-d absorption band between 200 and 300 nm. At lower Tb(3+) concentration, the Tb(3+) ions enter favorably 6H site around 240 nm and then enter 4F site around 270 nm. These compounds may provide a platform for modeling a new phosphor and application in the solid-state lighting field.

Involvement of the NADH oxidase-encoding noxA gene in oxidative stress responses in Corynebacterium glutamicum.

Corynebacterium glutamicum ORF NCgl0328, designated noxA, encodes an NADH oxidase enzyme. The noxA gene, which was preferentially expressed in the log growth phase, was found to be under the control of the whcA, whcB, and whcE genes, which play regulatory roles in cells under oxidative stress. While noxA transcription was minimal in whcE-deleted mutant cells (ΔwhcE) during growth, its transcription was maximal even in the stationary phase in ΔwhcA cells. The transcription levels of noxA in ΔwhcB and whcB-overexpressing cells were comparable to the levels only in the log growth phase in ΔwhcA and whcA-overexpressing cells, respectively. Direct binding of purified WhcA to the promoter region of noxA was observed in vitro. The DNA-protein interaction was only possible in the presence of the reducing agent dithiothreitol. A noxA-deleted mutant strain and a strain overexpressing the noxA gene (P180-noxA) were established, and these strains were found to exhibit defective cell growth. The ΔnoxA and P180-noxA strains were sensitive to the redox-cycling oxidant menadione, suggesting a role of noxA in redox balancing. Accordingly, the purified NoxA enzyme exhibited NADH-oxidizing activity. Taken together, these data show that noxA plays a role in oxidative stress responses and also that the gene is under direct control of the WhcA protein, which was shown to be a regulatory DNA-binding protein. Furthermore, the involvement and roles of the whcA, whcB, and whcE genes in regulating the expression of noxA were demonstrated.

Blue-emitting Eu2+-activated LaOX (X = Cl, Br, and I) materials: crystal field effect.

Novel blue-emitting LaOBr:Eu(2+) and LaOI:Eu(2+) phosphors have been successfully synthesized and compared to LaOCl:Eu(2+). The emission spectra of LaOX:Eu(2+) (X = Cl, Br, and I) show that the peak maxima change somewhat to the red-shift region; 425 nm for LaOCl:Eu(2+), 427 nm for LaOBr:Eu(2+), and 431 nm for LaOI:Eu(2+), which is quite opposite to one based on spectrochemical series (I(-) < Br(-) < Cl(-)). From diffuse reflectance spectra, the band gap energies for LaOCl, LaOBr, and LaOI host lattice are estimated as 5.53 eV (44,594 cm(-1)), 5.35 eV (43,142 cm(-1)), and 4.82 eV (38,868 cm(-1)), respectively, using the Kubelka-Munk function. For LaOX host lattices, the band gap energies are gradually decreased going from Cl to I as the order of energy levels of np orbitals is Cl 3p < Br 4p < I 5p. A quantum wave function calculation from crystal field theory (CFT) indicates the same tendency with experimental data in the LaOX:Eu(2+) (X = Cl, Br, and I) phosphor materials. With considerations of the radial wave function shape, crystral structure differences and electronegativities among phosphor materials, the splitting energies of 5d orbitals are calculaed; ΔECl = 14,597 cm(-1), ΔEBr = 14,864 cm(-1), ΔEI = 15,001 cm(-1) for LaOX:Eu(2+) (X = Cl, Br, and I). It is noteworthy that the crystal field strength decreases when the interatomic distance decreases, which is probably dependent on the ionic radius of halide ions in the series of LaOX:Eu(2+) phosphor materials.

Ridge preservation using demineralized bone matrix gel with recombinant human bone morphogenetic protein-2 after tooth extraction: a randomized controlled clinical trial.

PURPOSE: The aim of the present randomized controlled trial was to determine the safety and efficacy of injectable demineralized bone matrix (DBM) gel combined with recombinant human bone morphogenetic protein-2 (rhBMP-2) on alveolar ridge preservation after tooth extraction. MATERIALS AND METHODS: A total of 69 patients were randomly assigned to either a test group (n = 35) or a control group (n = 34). In the test group, DBM, together with rhBMP-2 (0.05 mg/mL; rhBMP-2/DBM) was transplanted into the extraction sockets. The control group received DBM alone. The safety of rhBMP-2/DBM was evaluated by oral examination, serum chemistry, and hematologic examination. The radiographic changes in alveolar bone height and width were measured using computed tomography scans performed immediately after transplant and again 3 months thereafter. RESULTS: Healing was uneventful in all subjects, with no anticipated adverse events and no clinically significant changes in the serum chemistry and hematologic findings. No meaningful immune response was found among the study groups. No significant difference was found in the radiographic changes of alveolar bone height and width (P > .05). CONCLUSIONS: This new injectable biomaterial can be used easily and safely in clinical applications.

Endoscopic submucosal dissection for early gastric cancer with undifferentiated histology: could we extend the criteria beyond?

BACKGROUND: Endoscopic submucosal desection (ESD) is an effective treatment for selected patients with early gastric cancer (EGC). The purpose of this study was to examine the short-term and long-term outcomes of ESD of undifferentiated early gastric cancer. METHODS: Data for 1,241 patients who underwent ESD for treatment of EGC between February 2003 and May 2010 were collected. We performed a retrospective analysis of the medical records of 74 patients diagnosed with undifferentiated EGC. We divided the enrolled cases into two groups: the expanded-criteria group (EC group) versus the non-EC group, according to lesion size, presence of ulceration, and pathologic review. RESULTS: Of a total of 74 lesions with undifferentiated EGC, as a result of pathologic examination the EC group included 29 cases and the non-EC group included 45 cases. The mean diameter of lesions was 19.86 ± 12.5 mm. The overall rates of en bloc resection and complete resection were 90.5% (67/74) and 73% (54/74), respectively. The curative resection rate was low at 31.1%. If limited to the pathologically diagnosed EC group, the curative resection rate was 79.3% (23/29). During median follow-up periods of 34 months (range 7-81), local recurrences were observed in 5.5% (4/74) of patients. All of these were in the non-EC group and all underwent noncurative resection. There was no mortality related to ESD for treatment of EGC during follow-up. CONCLUSIONS: ESD may be a feasible treatment for selected patients with undifferentiated EGC; this should be validated by development of new criteria for ESD for treatment of EGC.

Maturation of periodontal tissues following implantation of rhGDF-5/ß-TCP in one-wall intra-bony defects in dogs: 24-week histological observations.

OBJECTIVE: Although a previous study reported that recombinant human growth/differentiation factor-5 (rhGDF-5) coated onto a ß-tricalciumphosphate (ß-TCP) significantly enhanced periodontal regeneration, the long-term stability/maturation of the regenerated tissues has not been demonstrated. The objective of this study was to evaluate periodontal regeneration/maturation following application of rhGDF-5/ß-TCP using an established periodontal defect model and a 24-week healing interval. MATERIAL & METHODS: Unilateral, surgically created, 4 × 4 × 5 mm (length × width × height), one-wall, critical-size, intra-bony periodontal defects at the mandibular second and fourth premolar teeth in five young adult Beagle dogs received rhGDF-5/ß-TCP. Bilateral sites at the fourth premolar in the other four dogs served as pristine controls receiving mucogingival flap surgery without defect induction. The animals were euthanized at 24 weeks for histological analysis. Unpublished data from the previous 8-week study were used to compare tissue maturation between 8 and 24 weeks. RESULTS: Linear histometric observations of cementum and alveolar regeneration showed no significant differences between the 8- and 24-week observation intervals. However, parameters of periodontal tissue maturation showed significant differences between the observation intervals including increased fraction mineralized tissue and lamellar bone (p < 0.05) and decreased osteocyte counts (p < 0.05) at 24 weeks compared with 8 weeks. Although the count inserting Sharpey's fibre did not significantly change, regenerated cementum remote from the intact periodontal ligament appeared more highly mineralized and thicker at 24 weeks compared with 8 weeks, and compared with the pristine cementum. Minimal ß-TCP remained. CONCLUSIONS: These 24-week observations suggest that regenerated periodontal tissues in sites receiving rhGDF-5/ß-TCP undergo progressive maturation without debilitating aberrant tissue reactions.

Acquisition of human alveolar bone-derived stromal cells using minimally irrigated implant osteotomy: in vitro and in vivo evaluations.

OBJECTIVES: Implant osteotomy yields a substantial amount of bone in the form of bone chips entrapped within drill flutes, and can provide a promising cell source for tissue engineering. The aims of this study were to isolate human alveolar bone-derived stromal cells (hABCs) obtained during implant osteotomy, and to evaluate osteogenic differentiation capacity of hABCs. MATERIAL AND METHODS: Bone chips were obtained by minimally irrigated implant drilling technique from 10 human donors. Isolated cells were studied with respect to their colony-forming efficiency, surface marker expression by immunofluorescence staining, fluorescence-activated cell sorting analysis and self-renewal potency. To verify the differentiation activity, in vitro osteogenic and adipogenic gene expressions were evaluated by reverse transcription-polymerase chain reaction, and in vitro formation of mineralized nodule and adipocytes was also evaluated. In vivo bone-forming activity was assessed by ectopic transplantation in immunocompromised mice (n = 5). RESULTS: Human alveolar bone-derived stromal cells population with characteristics of mesenchymal stem cells was present in the isolated cells. Upon hABC transplantation, significant ectopic bone formation was induced with the characteristics of fully matured bone tissue. CONCLUSION: The data support the feasibility of using hABCs as a source of stem cells for dentoalveolar bone tissue reconstruction. The cell source has an advantage that the hABCs can be easily acquired during implant surgery.

The clinical effect of locally delivered minocycline in association with flap surgery for the treatment of chronic severe periodontitis: a split-mouth design.

OBJECTIVE: The purpose of this study was to determine the effectiveness of adjunctive application of locally delivered minocycline ointment associated with flap surgery for the treatment of patients with chronic severe periodontitis. MATERIAL AND METHODS: Twenty patients with chronic severe periodontitis were treated in a split-mouth study to either adjunctive application of locally delivered minocycline ointment in association with flap surgery (FM) or flap surgery only (FO); additional minocycline application was performed at 3 months post operation. Clinical evaluation of the plaque index, probing depth (PD), bleeding on probing (BOP), gingival recession, and clinical attachment level (CAL) was conducted at baseline and at 3 and 6 months after treatment. RESULTS: Clinical evaluations revealed that although both sites exhibited clinical improvement, there was a statistically significant reduction in PD (3.34 ± 0.03 mm) and BOP (78.01 ± 11.42%), and a significant gain of CAL (1.88 ± 0.21 mm) at the FM site compared with the FO site (reduction of PD and BOP: 2.62 ± 0.06 mm, 50.33 ± 15.01%, and gain of CAL: 1.55 ± 0.13 mm) at 6 months post operation (p < 0.05). CONCLUSION: Adjunctive application of locally delivered minocycline may be beneficial to the surgical treatment protocol of chronic severe periodontitis.

Maturation of alveolar bone following implantation of an rhGDF-5/PLGA composite into 1-wall intra-bony defects in dogs: 24-week histometric observations.

OBJECTIVE: The aim of this study was to evaluate long-term (24 weeks) alveolar bone maturation following surgical application of recombinant human growth/differentiation factor-5 (rhGDF-5) in an injectable poly-lactide-co-glycolide-acid (PLGA) composite carrier using an established periodontal defect model. METHODS: Routine, bilateral, 4 × 5 mm (width × depth), 1-wall, critical-size, intra-bony periodontal defects were surgically created at the 2nd and 4th mandibular premolar teeth in 10 Beagle dogs. The animals were randomized to receive (split-mouth design; defect sites in the same jaw quadrant getting the same treatment) rhGDF-5/PLGA high dose (188 µg/defect) versus sham-surgery control (5 animals), and rhGDF-5/PLGA low dose (37 µg/defect) versus carrier control (5 animals). The animals were euthanized for histometric analysis following a 24-week healing interval. RESULTS: Clinical healing was uneventful. The rhGDF-5 high dose significantly increased bone formation compared with controls in terms of bone area (p < 0.05), and a high degree of bone maturation was observed in the rhGDF-5/PLGA high dose group. Root resorption/ankylosis or other aberrant healing events were not observed. CONCLUSION: The rhGDF-5/PLGA appears to support alveolar bone healing/regeneration and the rhGDF-5/PLGA high dose uniquely increased maturation of the regenerated bone.