Transparency and sustainability in global commodity supply chains.

Over the last few decades rapid advances in processes to collect, monitor, disclose, and disseminate information have contributed towards the development of entirely new modes of sustainability governance for global commodity supply chains. However, there has been very little critical appraisal of the contribution made by different transparency initiatives to sustainability and the ways in which they can (and cannot) influence new governance arrangements. Here we seek to strengthen the theoretical underpinning of research and action on supply chain transparency by addressing four questions: (1) What is meant by supply chain transparency? (2) What is the relevance of supply chain transparency to supply chain sustainability governance? (3) What is the current status of supply chain transparency, and what are the strengths and weaknesses of existing initiatives? and (4) What propositions can be advanced for how transparency can have a positive transformative effect on the governance interventions that seek to strengthen sustainability outcomes? We use examples from agricultural supply chains and the zero-deforestation agenda as a focus of our analysis but draw insights that are relevant to the transparency and sustainability of supply chains in general. We propose a typology to distinguish among types of supply chain information that are needed to support improvements in sustainability governance, and illustrate a number of major shortfalls and systematic biases in existing information systems. We also propose a set of ten propositions that, taken together, serve to expose some of the potential pitfalls and undesirable outcomes that may result from (inevitably) limited or poorly designed transparency systems, whilst offering guidance on some of the ways in which greater transparency can make a more effective, lasting and positive contribution to sustainability.

Osseointegration in osteoporotic-like condition: A systematic review of preclinical studies.

Osteoporosis is one of the most common skeletal disorders affecting a significant percentage of people worldwide. Research data suggested that systemic diseases such as osteoporosis could act as risk factors for osseointegration, jeopardizing the healing process and thus the predictability of dental implant success on compromised patients. It is well accepted that preclinical studies in animal models reproducing the osteoporotic condition are one of the most important stages in the research of new biomaterials and therapeutic modalities. The aim of this systematic review was to investigate whether osteoporosis compromises dental implant osseointegration in experimental osteoporotic-like conditions. A 3-stage systematic literature research was conducted in MEDLINE via OVID and EMBASE up to and including March 2017. Experimental studies reporting on dental implant osseointegration on different osteoporotic animal models were assessed. The studies had to report on the percentage of bone-to-implant contact (%BIC) as the primary outcome. ARRIVE guidelines for reporting on animal research were applied to evaluate the methodological quality and risk of bias of the studies. Fifty-seven studies met the inclusion criteria and were assessed qualitatively. The most adopted animal model was the rat. A variability of %BIC values was observed, ranging from 30% to 99% and from 26% to 94% for the healthy and osteoporotic group, respectively. The great majority (47) of the included studies concluded that estrogen deficiency significantly affects BIC values, 9 studies stated that it was not possible to observe statistical differences in BIC between ovariectomized and healthy groups and 1 study did not provide a comparison between the healthy and osteoporotic group. Owing to the great heterogeneity in implant surface, study design, observation time-points, site of implant placement and reported outcomes, a meta-analysis could not be performed. An overall high risk of bias was observed, owing to the limited information on animal housing and husbandry, baseline characteristics and health status, ethical statement and allocation to the experimental groups provided. Although the available studies seem to suggest a lower osseointegration in osteoporotic-like conditions, no robust conclusions can be drawn due to the great heterogeneity and overall low quality of the available studies. Future studies with emphasis on minimizing the possible sources of bias and evaluating osseointegration of dental implants placed into jawbones instead of long bones are warranted.

Degradation pattern of a porcine collagen membrane in an in vivo model of guided bone regeneration.

BACKGROUND AND OBJECTIVE: Although collagen membranes have been clinically applied for guided tissue/bone regeneration for more than 30 years, their in vivo degradation pattern has never been fully clarified. A better understanding of the different stages of in vivo degradation of collagen membranes is extremely important, considering that the biology of bone regeneration requires the presence of a stable and cell/tissue-occlusive barrier during the healing stages in order to ensure a predictable result. Therefore, the aim of this study was to investigate the degradation pattern of a porcine non-cross-linked collagen membrane in an in vivo model of guided bone regeneration (GBR). MATERIAL AND METHODS: Decalcified and paraffin-embedded specimens from calvarial defects of 18, 10-month-old Wistar rats were used. The defects were treated with a double layer of collagen membrane and a deproteinized bovine bone mineral particulate graft. At 7, 14 and 30 days of healing, qualitative evaluation with scanning electron microscopy and atomic force microscopy, and histomorphometric measurements were performed. Markers of collagenase activity and bone formation were investigated using an immunofluorescence technique. RESULTS: A significant reduction of membrane thickness was observed from 7 to 30 days of healing, which was associated with progressive loss of collagen alignment, increased collagen remodeling and progressive invasion of woven bone inside the membranes. A limited inflammatory infiltrate was observed at all time points of healing. CONCLUSION: The collagen membrane investigated was biocompatible and able to promote bone regeneration. However, pronounced signs of degradation were observed starting from day 30. Since successful regeneration is obtained only when cell occlusion and space maintenance exist for the healing time needed by the bone progenitor cells to repopulate the defect, the suitability of collagen membranes in cases where long-lasting barriers are needed needs to be further reviewed.

Protein expression during early stages of bone regeneration under hydrophobic and hydrophilic titanium domes. A pilot study.

BACKGROUND AND OBJECTIVES: There is significant evidence that, during the early stages of osseointegration, moderately rough hydrophilic (SLActive) surfaces can accelerate osteogenesis and increase bone-to-implant contact in comparison to hydrophobic (SLA) surfaces. However, very little is known regarding the molecular mechanisms behind the influence that surface chemistry modifications to increase hydrophilicity determine on bone healing. The aim of this study was to describe for the first time the proteins and related signalling pathways expressed during early osseous healing stages under SLA and SLActive titanium domes for guided bone regeneration. MATERIAL AND METHODS: One SLA and 1 SLActive dome with an internal diameter of 5.0 mm and a height of 3.0 mm were secured to the parietal bones of nine 6-month-old male New Zealand rabbits. Three animals were randomly euthanized at 4, 7 and 14 days and the newly formed tissues retrieved under the domes were analysed with liquid chromatography-mass spectrometry/mass spectrometry. STRING and KEGG databases were applied for Gene Ontology and pathway analyses. RESULTS: A different modulation of several pathways was detected between the 2 groups at all healing times. The main differences in the osseous healing response associated to the 2 surfaces were related to pathways involved in regulating the inflammatory response, differentiation of osteoblast precursors and skeletogenesis. At day 7, the highest number of proteins and the highest cellular activity were observed in both groups, although a more complex and articulated proteome in terms of cellular metabolism and signal transduction was observed in SLActive samples. CONCLUSION: This is the first study describing the proteome expressed during early healing stages of guided bone regeneration and osseointegration. A combination of enhanced early osteogenic response and reduced inflammatory response were suggested for the hydrophilic group. Future studies are needed to corroborate these findings and explore the molecular effects of different titanium surfaces on the cascade of events taking place during bone formation.

The effect of experimental osteoporosis on bone regeneration: part 2, proteomics results.

OBJECTIVES: To identify and describe protein expression in a Wistar rat calvarial critical size defect (CSD) model following treatment with guided bone regeneration in healthy and osteoporotic conditions. MATERIAL AND METHODS: Thirty-six 10-month-old female Wistar rats were used. Half of them were ovariectomized (OVX) and fed with a low-calcium diet to induce an osteoporotic-like status. In each animal of both groups, two 5-mm calvarial CSDs were treated with deproteinized bovine bone mineral graft particles and a bilayer collagen membrane. Six OVX and six control rats were randomly euthanized at 7, 14, and 30 days. One defect/animal was randomly chosen for proteomic analysis. Differently expressed proteins between the two groups were identified with matrix-assisted laser desorption time-of-flight mass spectrometry and liquid chromatography-mass spectrometry/mass spectrometry. RESULTS: At 7 days, 29 and 27 proteins were, respectively, identified in the healthy and OVX animals. At 14 days, 103 proteins were detected in the healthy controls and 20 proteins in the OVX rats, while at 30 days, 31 and 75 proteins were identified, respectively. Only limited proteins known to play a role in the later stages of bone formation and maturation were identified within the animals 'proteomes. DISCUSSION: The osseous formation process was quite immature even at 30 days of healing. An overexpression of inflammatory and stress response pathways was detected in the OVX animals, as well as a tendency toward a delayed maturation of the osseous wound and a reduced/delayed differentiation of osteoblast cell precursors.

Panoramic measures for oral bone mass in detecting osteoporosis: a systematic review and meta-analysis.

Different quantitative and qualitative indices calculated on oral panoramic radiographs have been proposed as useful tools to screen for reduced skeletal bone mineral density (BMD). Our aim was to systematically review the literature on linear and qualitative panoramic measures and to assess the accuracy of these indices by performing a meta-analysis of their sensitivity and specificity. The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement was followed. Fifty studies were included in the qualitative appraisal and 19 were considered for meta-analysis. The methodological quality of the retrieved studies, assessed with the QUADAS-2 tool, was on average low. Three indices were reported by most of the studies: mandibular cortical width, panoramic mandibular index, and the Klemetti index. Mandibular cortical width presented with a better accuracy in excluding osteopenia/osteoporosis (specificity), since patients with a cortical width more than 4 mm had a normal BMD in 90% of the cases. Almost all studies used a cutoff of 0.3 for the panoramic mandibular index, resulting in an estimated sensitivity and specificity in detecting reduced BMD, respectively, of 0.723 (SE 0.160; 95% confidence interval [CI], 0.352-0.926) and 0.733 (SE 0.066; 95% CI, 0.587-0.841). The presence of any kind of mandibular cortical erosion gave an estimated sensitivity and specificity in detecting reduced BMD, respectively, of 0.789 (SE 0.031; 95% CI, 0.721-0.843) and 0.562 (SE 0.047; 95% CI, 0.47-0.651) and a sensitivity and specificity in detecting osteoporosis, respectively, of 0.806 (SE 0.105; 95% CI, 0.528-0.9200) and 0.643 (SE 0.109; 95% CI, 0.417-0.820). The mandibular cortical width, panoramic mandibular index, and Klemetti index are overall useful tools that potentially could be used by dentists to screen for low BMD. Their limitations are mainly related to the experience/agreement between different operators and the different image quality and magnification of the panoramic radiographs.

Radiographic and clinical outcomes of implants placed in ridge preserved sites: a 12-month post-loading follow-up.

OBJECTIVE: The aim of this clinical study was to evaluate the interproximal radiographic bone levels and the survival/success rate of dental implants placed in alveolar ridges previously preserved with a synthetic bone substitute or a bovine xenograft. MATERIAL AND METHODS: Alveolar ridge preservation was performed in 27 patients who were randomly assigned in two groups. In the test group (n = 14), the extraction socket was treated with a synthetic bone graft Straumann Bone Ceramic; SBC and a collagen barrier, whereas in the control group (n = 13) a deproteinized bovine bone mineral (DBBM) and the same collagen barrier were used. After 8 months of healing, titanium dental implants with a hydrophilic surface were placed in the preserved ridges. During surgery, 9/13 implants in the SBC group and 8/12 implants in the DBBM group presented with either dehiscence or fenestration defects and required additional bone augmentation. The implants were loaded at 4 months following placement and were followed up for 1 year post-loading. Interproximal radiographic bone levels were evaluated in standardized periapical radiographs at loading and 1 year post-loading. Probing pocket depth, gingival recession and bleeding upon probing were recorded at implants and neighbouring teeth. The success rate of the implants was evaluated according to criteria set by Albrektsson et al. (1986). RESULTS: The survival rate of the implants in both groups was 100% at 1-year post-loading. No statistically significant differences in any of the clinical and radiographic measurements were detected between the two groups (P < 0.05). The success rate of the implants was 84.6% (11/13) in the SBC group and 83.3% (10/12) in the DBBM group. CONCLUSION: Equivalent success and survival rates (as well as similar radiographic changes) of dental implants placed in alveolar ridges previously preserved with SBC or DBBM should be anticipated.

Effect of immediate or delayed loading following immediate placement of implants with a modified surface.

OBJECTIVE: to evaluate the effect of the timing of loading on bone-to-implant contact (BIC) following immediate placement of implants with a hydrophilic sandblasted, large-grit and acid-etched surface (modSLA) into fresh extraction sockets in a minipig model. MATERIAL AND METHODS: six minipigs were used in this study. In each hemi-mandible, two conical shape implants (TE, Straumann implants) with a hydrophilic surface (modSLA) were placed in fresh extraction sockets. In one side of the mandible (control), two implants were immediately placed in fresh extraction sockets. The implants were loaded after 4 weeks of healing. At the contralateral side (test), two implants were immediately placed and loaded. After 8 weeks of healing, the animals were sacrificed and histologically analysed. RESULTS: during the experimental period, no implants were lost and all of them presented to be osseointegrated. The percentage of BIC was similar in both groups: 66.1% and 65.1% for the control and test group, respectively. Furthermore, the distance from the shoulder of the implant to bone crest and the distance from the shoulder to the first BIC were similar in both groups. CONCLUSION: immediate implant placement and loading showed similar BIC with immediate placement and delayed loading when implants with a modSLA surface were used. Both procedures showed similar buccal bone crest levels, which presented some resorption irrespective of the treatment modality.

An outline of competencies and the appropriate postgraduate educational pathways in implant dentistry.

The use of dental implants has become a widely accepted and well-documented treatment option offering to both patients and dentists an alternative to traditional treatment modalities and at the same time opening a brand new area in dental postgraduate education. As such, it is necessary to define the competencies that the graduate student/dentist will need at the different levels of clinical practice in Implant Dentistry and the educational pathways that are required to convey those competencies in a structured manner. The present position paper provides an initial suggestion for the knowledge, skills and behaviour necessary for a graduate student to practice implant dentistry at the different levels of clinical complexity. An outline of the necessary competencies and structure of various levels of postgraduate university courses is provided together with different educational approaches to support them. The present paper should be evaluated as a platform for discussion for future development of postgraduate curricula in implant dentistry rather than a manual on how to design and operate such curricula.

Gentamicin used as an adjunct to GTR.

OBJECTIVES: To evaluate in a discriminating "capsule" model whether local application of gentamicin may have an added effect on bone formation produced by Bio-Oss and guide tissue regeneration (GTR). MATERIAL AND METHODS: Thirty male 3-month-old Wistar rats were used. After elevation of muscle-periosteal flaps, a rigid hemispherical Teflon capsule, loosely packed with 0.025 g of Bio-Oss impregnated with 2 mg/ml gentamicin sulfate (Garamycin), was placed with its open part facing the lateral bone surface of the mandibular ramus (test) in one side of the jaw. A capsule filled only with Bio-Oss (control) was placed on the contralateral side of the jaw. After healing periods of 1, 2 and 4 months, groups of 10 animals were sacrificed and the specimens were processed for histological examination. The volumes of (1) the space created by the capsule, (2) newly formed bone, (3) Bio-Oss particles, (4) loose connective tissue, and (5) acellular space in the capsule were estimated by a point-counting technique in three to four histological sections of each specimen, taken by uniformly random sampling. RESULTS: The histological evaluation showed limited but increasing bone fill in the capsules from 1 to 4 months in both the test and control sides. After 4 months, the newly formed bone occupied 11.9% (CV: 0.39) of the space created by the capsules at the test sides versus 13.2% (CV: 0.41) at the control sides. There was no statistical significant difference between test and control specimens at any observation time (p>0.05). CONCLUSION: It is concluded that local application of gentamicin has no added effect on bone formation when combined with Bio-Oss and GTR.

Osteogenesis by guided tissue regeneration and demineralized bone matrix.

AIM: To evaluate in a discriminating capsule model whether bone formation by guided tissue regeneration (GTR) may be influenced by concomitant implantation of demineralized bone matrix (DBM). MATERIALS AND METHODS: Thirty 4-month-old male albino rats of the Wistar strain were used in the study. Following surgical exposure of the mandibular ramus, a hemispherical, Teflon capsule (5.0 mm in diameter), loosely packed with a standardized amount of DBM, was placed with its open part facing the lateral bone surface of the ramus. At the contralateral side, an empty capsule was placed, serving as control. After healing periods of 15, 30, and 120 days, groups of 10 animals were sacrificed and 40-70 microm thick undecalcified sections of the capsules were produced. In the sections, the cross-sectional areas of (1) the space created by the capsule, (2) newly formed bone, (3) DBM particles, (4) loose connective tissue as well as the (5) height of the capsules, and (6) that of the newly formed bone were measured. RESULTS: Increasing bone fill was observed in both test and control sites from 30 to 120 days. After 30 days of healing, the mean amount of bone was approx. 3% of the cross-sectional area of the capsules at the test sites while it was 8% in the control sites (p<0.05). However, no statistically significant differences were observed between the test (46%) and control (64%) sites after 120 days regarding any of the measured parameters (p>0.05). The newly formed bone in the DBM group at 120 days, on the other hand, appeared more dense than that in the control capsules. CONCLUSION: DBM used as an adjunct to GTR did not provide any added effect on bone formation but increased the density of the newly formed bone.

Denaturation of demineralized bone matrix significantly reduces bone formation by guided tissue regeneration.

AIM: To examine in a discriminating capsule model whether denaturation of demineralized bone matrix (DBM) by heating may influence bone formation. MATERIALS AND METHODS: DBM was produced from the long bones of rats. Half the portion of DBM was denatured by heating in distilled water for 20 min at temperatures between 70 degrees C and 90 degrees C. Prior to the study, the destruction of the osteoinductive properties of the DBM was confirmed in three rats following intramuscular implantation. Thirty, 4-month-old, male albino rats of the Wistar strain were used in the study. Following surgical exposure of the mandibular ramus, a hemispherical Teflon capsule (internal diameter = 5.0 mm) was placed, with its open part facing the lateral aspect of the ramus. On one side (test side), the capsule was loosely packed with denatured DBM, while on the contralateral side, serving as control, the capsule was loosely packed with the same amount of non-denatured DBM. After healing periods of 30, 60, and 120 days, groups of 10 animals were killed and 40-70 microm thick undecalcified sections of the capsules were produced. Three sections from each specimen, representing the mid-portion of the capsule, were subjected to histological analysis and computer-assisted planimetric measurements. RESULTS: Increasing amounts of newly formed bone were observed in both test and control capsules during the experimental period. At 4 months, the new bone formed in the control capsules occupied 46.7% of the cross-sectional area of the capsules, while it was only 19.1% in the test capsules (P<0.05). CONCLUSION: Denaturation of DBM by heating significantly reduces bone formation by guided tissue regeneration.

Evaluation of a cell-permeable barrier for guided tissue regeneration combined with demineralized bone matrix.

AIM: To evaluate whether bone formation by guided tissue regeneration (GTR) and demineralized bone matrix (DBM) can be enhanced by the use of a cell-permeable Teflon barrier allowing the penetration of undifferentiated mesenchymal cells from the surrounding soft tissues. MATERIAL AND METHODS: DBM was produced from the long bones of rats, and its bone-inductive properties were tested in three rats prior to the study by intramuscular implantation. Thirty, 4-month-old, male albino rats of the Wistar strain were used. Following surgical exposure of the mandibular ramus, a cell-permeable Teflon capsule, loosely packed with DBM, was placed with its opening facing the lateral surface of the ramus (test side). At the contralateral side, serving as control, a non-perforated (cell-occlusive) Teflon capsule, loosely packed with the same amount of DBM, was placed. After healing periods of 30, 60, and 120 days, groups of 10 animals were killed, and 40-70 microm thick undecalcified sections of the capsules were produced. RESULTS: Computer-assisted planimetric measurements on the histological sections disclosed similar amounts of newly formed bone in both test and control capsules. After 4 months, the new bone in the control capsules occupied 45.0% of the cross-sectional area of the capsule, while it was 50.5% in the test capsules. This difference was not statistically significant (P<0.05). CONCLUSION: Similar amounts of bone formed in cell-permeable and cell-occlusive capsules grafted with DBM, suggesting that invasion of undifferentiated mesenchymal cells from the surrounding soft tissues into the barrier-protected area is unnecessary for bone formation with GTR.

Deproteinized bovine bone used as an adjunct to guided bone augmentation: an experimental study in the rat.

BACKGROUND: Promising results have been reported following treatment of periodontal and peri-implant bone defects with deproteinized bovine bone grafts, but their influence on bone formation has not been clarified. PURPOSE: The goal of this study was to examine whether implantation of deproteinized bovine bone (Bio-Oss, Geistlich AG, Wolhusen, Switzerland) influences bone formation when used as an adjunct to guided bone augmentation (GBA). MATERIALS AND METHODS: A rigid, hemispherical, Teflon capsule was loosely packed with a standardized quantity of Bio-Oss and placed with its open part facing the lateral surface of the mandibular ramus (test) in 30 rats. At the contralateral side of the jaw, an empty capsule was placed (control). Groups of 10 animals were sacrificed after 1, 2, and 4 months. The volumes of the space created by the capsule and of the (1) newly formed bone, (2) remaining Bio-Oss particles, (3) soft connective tissue, and (4) acellular space in the capsule were estimated by a point-counting technique in three or four histologic sections, taken by uniformly random sampling. RESULTS: Bone formation at 1 month was limited in both tests and controls. After 2 months, the mean volume of the newly formed bone occupied 9.0% of the space created by the capsule in the test specimens compared with 23.8% in the control specimens (p < .01). After 4 months, the respective figures were 11.6% (tests) versus 38.7% (controls) (p < .01). CONCLUSION: It can be concluded that Bio-Oss, used as an adjunct to GBA, interferes with bone formation.