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This study compared higher education dental undergraduate student performance in online assessments with performance in traditional paper-based tests and investigated students' perceptions of the fairness and acceptability of online tests, and showed performance to be comparable. The project design involved two parallel cross-over trials, one in Year 3 ( n = 132) of the dental curriculum, one in Year 5 ( n = 134). A total of 266 students undertook related tests of the same knowledge base in both online and traditional paper formats. Order of presentation of the test form was randomized. One hundred and thirty-two students in Year 3 additionally completed questions concerning their perceptions of the acceptability and fairness of the online examination process. Focus group discussions were held with groups of students ( n = 30) from both Year 3 and 5 to explore their perceptions of the online format. The online tests were created using the commercial software package MaxExam (Bristol, UK). The results were analysed using repeated measures analysis of variance (ANOVA) with the order of presentation being entered as a variable in the analysis. The results of the study showed that for both Years 3 and 5 students there was a high degree of consistency in performance between the two versions of the tests, although a minority of students performed better in the online version of the test. Over 70% of students rated the online test as acceptable, and 90% felt that the online format did not disadvantage them even in a 'high-stakes' situation. From these results, we conclude that online assessment does not confer any disadvantage to students. Students perceive such assessment to be both fair and acceptable, and to have some advantages over the traditional paper-based methods of assessment. [ABSTRACT FROM AUTHOR]

The origin of the stromal, stellate and multinucleate cells in oral giant cell fibroma is unclear. Sixteen giant cell fibromas were stained immunocytochemically for keratin (MNF 116), vimentin, S-100 protein, neurofilaments, glial fibrillary acidic protein, alpha-smooth muscle actin, desmin, CD31 (PECAM-1), CD68, Factor XIIIa and prolyl 4-hydroxylase (5B5). In all cases positive staining was found with vimentin and prolyl 4-hydroxylase, indicating a functional fibroblast phenotype. Reactivity for Factor XIIIa was seen in two cases and in only one was a small number of giant cells stained, suggesting that the majority of oral giant cell fibromas are unrelated to the histologically similar fibrous papule of the nose or facial angiofibroma. [ABSTRACT FROM AUTHOR]

Objectives This study evaluated buccal bone crest remodeling, socket composition after healing, and dimensional ridge preservation after flapless tooth extraction procedures with or without a xenograft comparing histomorphometric and microcomputed tomographic (micro- CT) data. Material and Methods The mandibular premolars of eight dogs were extracted without flaps. One socket on each side received a grafting material (test group), and the other remained only with a blood clot (control group). Twelve weeks after treatment, buccal bone crest, alveolar ridge dimensions, and composition were analyzed by histomorphometry and micro- CT. Results Two- and three-dimensional evaluations showed better results for the grafted group when compared to the non-grafted group. Conclusion The flapless alveolar ridge preservation procedure with deproteinized bovine bone material enhanced buccal bone crest, alveolar ridge dimensions and bone formation when compared to sockets with the blood clot only, as observed by histomorphometric and micro- CT analysis. [ABSTRACT FROM AUTHOR]

Objectives The aims of this randomized clinical trial were to compare the dimensional changes and the histological composition after using deproteinized bovine bone mineral ( DBBM) or deproteinized bovine bone mineral with 10% collagen ( DBBM-C) and a collagen membrane in ridge preservation procedures. Material and methods Patients who required an extraction and a subsequent implant-supported rehabilitation at a non-molar site were recruited. After extraction, a cone beam computed tomography ( CBCT) was performed and sites were randomly treated either with DBBM or DBBM-C plus a collagen membrane. At 5 months, before implant placement, a second CBCT was performed and a biopsy of the area was obtained. A blinded investigator superimposed the CBCTs and performed measurements to determine bone volume changes between the two time points. Additionally, a histomorphometric analysis of the biopsies was performed in a blinded manner. Results Eleven sites belonged to the DBBM group and eleven to the DBBM-C group. All together, a significant reduction in height and width was observed at 5 months of healing, but no statistically significant differences were observed between the DBBM and the DBBM-C group. The histomorphometric analysis revealed a similar composition in terms of newly formed bone, connective tissue and residual graft particles in both groups. Conclusions Deproteinized bovine bone mineral with 10% collagen showed a similar behaviour as DBBM not only in its capacity to minimize ridge contraction but also from a histological point of view. Thus, both graft materials seem to be suitable for ridge preservation procedures. [ABSTRACT FROM AUTHOR]

Aim: The aim of this article was to systematically review histological and histomorphometrical data from literature that provide information regarding the effect of alveolar ridge preservation procedures on healing after tooth extraction in humans. Materials and methods: The MEDLINE-PubMed and the Cochrane CENTRAL databases were searched up to September 2012; 38 papers were selected from 646 founded. A meta-analysis was performed regarding the variations in the mean percentage of Bone, Connective Tissue and Residual Graft Material between three different types of Procedures. Results: The highest value regarding bone percentages is produced at 3 months by Procedures with Allografts (54.4%), while the lowest is obtained, at 5 months, by those using Xenografts (23.6%). Referring to connective tissue, the highest and lowest values are shown at 7 months, with Allografts (67%) and Alloplasts (27.1%), respectively. Regarding residual graft material, the lowest rates are displayed by Procedures with Allografts (12.4-21.11%), while those using Xenografts and Alloplasts showed the best results at 7 months (37.14 and 37.23%). No statistical difference was found. Conclusions: With the limitations due to the features of the selected papers, no major histological and histomorphometrical differences arose among different procedures or when compared to spontaneous healing. Thus, it might be argued that in preserved sites it is unnecessary to wait over 3 to 4 months prior to implant insertion. [ABSTRACT FROM AUTHOR]

Objective The aim was to examine the tissue composition of extraction sockets that had been grafted with deproteinized bovine bone mineral and allowed to heal for 6 months. Material and methods Twenty-five subjects with one tooth each scheduled for extraction and replacement with dental implants were recruited. The assigned teeth were carefully removed. The site/patient was thereafter allocated to a test or a control group. In the test group patients, Bio-Oss® Collagen was placed to fill the fresh extraction socket while in the controls no grafting was performed. After about 6 months of healing, a biopsy was sampled from the center of the extraction site. The specimens were decalcified, embedded in paraffin, sectioned, and stained in HTX. The proportions occupied by mineralized bone, osteoid, bone marrow, fibrous tissue, and Bio-Oss® particles were determined by morphometric point counting. Results Mineralized bone made up 57.4 ± 12.4% of the control sites (C) and 48.9 ± 8.5% of the T1 sites (graft material not included). The amount of bone marrow (C: 7.1 ± 6.1%, T1: 2.1 ± 3.1%) and osteoid (C: 7.3 ± 4.9%, T1: 1.9 ± 2.1%) was about five times greater in the control than in the test sites. Fibrous tissue comprised 23.1 ± 16.3% (C) and 40.0 ± 11.9% (T1). I n the T2 sites (graft material included), the percentage mineralized bone was 39.9 ± 8.6 while the proportions of bone marrow and osteoid were 1.8 ± 2.5% and 1.6 ± 1.8%. Fibrous tissue occupied 32.4 ± 9.2% and Bio-Oss® particles 19.0 ± 6.5% of the T2 sites. Conclusion Placement of the biomaterial in the fresh extraction socket retarded healing. The Bio-Oss® particles were not resorbed but became surrounded by new bone. This may explain why grafted extraction sites may fail to undergo dimensional change. [ABSTRACT FROM AUTHOR]

Background Advanced laryngeal and hypopharyngeal squamous cell carcinomas carry an inherent risk of invading thyroid parenchyma leading to the incorporation of a hemithyroidectomy or total thyroidectomy as part of a total laryngectomy. In some centres, thyroid gland removal occurs routinely during surgery for T3 and T4 laryngopharyngeal carcinoma. However, the incidence of invasion is low, and therefore, thyroid-sparing surgery must be considered for select cases. Objective of review The primary goal of the review is to assess the true incidence of thyroid gland invasion in laryngopharyngeal carcinoma. Utilising this data we aim to identify risk factors and clinical predictors of thyroid gland invasion to facilitate in a more targeted approach in the surgical management of advanced laryngopharyngeal carcinoma. Type of review A systematic review and meta-analysis of all published data and review of case series at Newcastle upon Tyne Hospitals (NuTH). Search strategy MEDLINE (1946-2012) and EMBASE (1980-2012) were searched. Evaluation method A single reviewer conducted the systematic review with a follow-up ancestry search. Studies publishing case series of T3 and T4 laryngeal and hypopharyngeal carcinoma treated by total laryngectomy or laryngopharyngectomy and partial or total thyroidectomy, with pathological assessment for thyroid gland invasion rates were selected. Articles published prior to 1977 were excluded due to the advent of whole organ sectioning. Results The literature search identified 16 studies suitable for inclusion, with 1180 cases. The NuTH case series identified 107 patients. The overall pooled incidence of thyroid gland invasion in 1287 patients is 10.7% (95% CI 7.6-14.2). Patients with primary subglottic tumours (relative risk 7.5; 95% CI 4.3-13.0) and disease extension into the subglottis (relative risk 4.3; 95% CI 2.5-7.2) have a significantly higher relative risk of thyroid gland invasion. Radiorecurrent tumours and hypopharyngeal tumours did not have an increased risk of thyroid gland invasion. Conclusion Advanced laryngeal and hypopharyngeal carcinomas involving the subglottis carry a significantly elevated risk of thyroid gland invasion compared with those that spare this subsite. The overall incidence of thyroid gland invasion is low, and therefore, thyroidectomy should be reserved for cases considered to be at risk as opposed to a being a routine measure for all total laryngectomies. [ABSTRACT FROM AUTHOR]

Objective Tooth extraction is considered as the starting point of jaw atrophy via osteoclast activity stimulation. The maintenance of dental alveolar bone depends on surgery procedure and use of materials to maintain prior space favoring bone regeneration. Among substitutes used in dentistry to fill bone defects, Ostim-Pastes ( Ostim®) is a nanocrystalline paste tested for treatment of severe clinical conditions. This research first investigated the effect of Ostim on alveolar healing, comparing in the same healthy subjects, an Ostim®-filled socket with a not-filled one. Moreover, it also proposed a new surgical protocol for the post-extractive socket treatment using the graft materials without elevation of full-thickness flaps. Material and methods Fourteen patients were enrolled to bilateral maxillary or mandibular extraction that was performed without elevation of full-thickness flaps. In each patient, one socket was filled using Ostim®, and the other one was allowed to undergo natural healing. No suture was carried out. Clinical and biologic parameters were screened at 1, 7, and 14 days. Results Obtained results evidenced that nanocrystalline hydroxyapatite supports bone regeneration, increasing the synthesis of pro-osteogenic factors as bone morphogenetics protein ( BMP)-4, BMP-7, alkaline phosphatase, and osteocalcin. Moreover, filling post-extractive socket with nanocrystalline hydroxyapatite paste leads to a complete epithelialization already at 7 days after extraction, despite the fact that the teeth were extracted without elevation of full-thickness flaps . The improved epithelialization is mediated by increased vascular endothelial growth factor ( VEGF) expression. No significant change was observed in inflammatory parameters, with exception of an early and transient IL-1β induction, that could trigger and improve alveolar healing. Conclusions Clinical and biomolecular observations of this explorative study evidenced that nanocrystalline hydroxyapatite improves alveolar socket healing, increasing angiogenesis, epithelialization, and osteogenesis, also in absence of elevation of full-thickness flaps. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to perform an ultrastructural study of the bone-to-biomaterial interface and biomaterial mineral degradation in retrieved bone biopsies following maxillary sinus augmentation using bovine xenografts (Endobon®) in 15 clinical cases. Materials and methods Nine months after sinus lifting, bone cores were harvested from the maxillary sinus. The specimens were processed for observation under a scanning electron microscope with backscattered electron imaging ( SEM- BSE). In addition, chemical analysis and elemental mapping of the mineral composition were generated using a microanalytical system based on energy-dispersive X-ray spectrometry ( EDX). Results No clinical complications occurred during surgery. Scanning electron microscopy revealed that newly formed bone was closely attached to the xenograft. Elemental analysis showed a significantly high Ca/ P ratio in the residual biomaterials (3.031 ± 0.104) compared with the interface (2.908 ± 0.115) and new bone (2.889 ± 0.113), which suggests that there may be a gradual diffusion of Ca ions from the biomaterial into the newly forming bone at the interface as part of the biomaterial's resorption process. EDX analysis of the residual bovine biomaterial showed particle categories with different mean Ca/ P ratios according to size, pointing to different stages of the resorption process. Conclusions The biomaterial proved to be biocompatible and osteoconductive when used as a bone substitute for maxillary sinus elevation. The grafting material used is not a completely resorbable material over the time period covered by this study. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to compare a nanocrystalline hydroxyapatite ( NCHA), NanoBone® and a deproteinized bovine bone mineral ( DBBM), Bio-Oss® with a collagen membrane on the horizontal ridge width alterations following tooth extraction, in addition to histologic aspects of the grafted extraction sockets. Material and methods In this randomized clinical trial, 28 symmetrical, non-molar, extraction sockets using a split-mouth design in 12 patients (eight women and four men; aged 21-60; mean 44.6 ± 11.4 years), were randomly selected in the first group to be grafted with DBBM granules covered with a collagen membrane and in the other group grafted with NCHA covered with a collagen membrane. Following extraction horizontal ridge width was measured using caliper and was blindly compared to the dimensions measured prior to implant placement, at the 6- to 8-month follow-up. Subsequently, a 2 × 6 mm trephine core was obtained with aid of acrylic stent and routine histologic preparation was performed on the specimens. Results The width of the DBBM group decreased from 7.75 ± 1.55 to 6.68 ± 1.85 mm ( P < 0.05), whereas the width of the NCHA group decreased from 7.36 ± 1.94 to 6.43 ± 2.08 mm ( P < 0.05). The mean between-group difference did not reach statistical significance ( P = 0.62). Furthermore, histologic and histomorphometric analyses revealed 28.63 ± 12.53% vital bone in NCHA group vs. 27.35 ± 12.39% in DBBM group, and no statistically significant difference between the groups ( P = 0.68). Conclusion Socket preservation using either NCHA or DBBM in combination with collagen membrane, results in similar, limited horizontal ridge width alterations following tooth extraction. [ABSTRACT FROM AUTHOR]

Objective This systematic review aims to evaluate the scientific evidence on the efficacy in the surgical protocols designed for preserving the alveolar ridge after tooth extraction and to evaluate how these techniques affect the placement of dental implants and the final implant supported restoration. Material and methods A thorough search in MEDLINE- PubMed, Embase and the Cochrane Central Register of controlled trials ( CENTRAL) was conducted up to February 2011. Randomized clinical trials and prospective cohort studies with a follow-up of at least 3 months reporting changes on both the hard and soft tissues (height and/or width) of the alveolar process (mm or %) after tooth extraction were considered for inclusion. Results The screening of titles and abstracts resulted in 14 publications meeting the eligibility criteria. Data from nine of these 14 studies could be grouped in the meta-analyses. Results from the meta-analyses showed a statistically significant greater ridge reduction in bone height for control groups as compared to test groups (weighted mean differences, WMD = −1.47 mm; 95% CI [−1.982, −0.953]; P < 0.001; heterogeneity: I2 = 13.1%; χ2 P-value = 0.314) and a significant greater reduction in bone width for control groups compared to the test groups ( WMD = −1.830 mm; 95% CI [−2.947, −0.732]; P = 0.001; heterogeneity: I2 = 0%; χ2 P-value = 0.837). Subgroup analysis was based on the surgical protocol used for the socket preservation (flapless/flapped, barrier membrane/no membrane, primary intention healing/no primary healing) and on the measurement method utilized to evaluate morphological changes. Meta-regression analyses demonstrated a statistically significant difference favoring the flapped subgroup in terms of bone width (meta-regression; slope = 2.26; 95% IC [1.01; 3.51]; P = 0.003). Conclusions The potential benefit of socket preservation therapies was demonstrated resulting in significantly less vertical and horizontal contraction of the alveolar bone crest. The scientific evidence does not provide clear guidelines in regards to the type of biomaterial, or surgical procedure, although a significant positive effect of the flapped surgery was observed. There are no data available to draw conclusions on the consequences of such benefits on the long-term outcomes of implant therapy. [ABSTRACT FROM AUTHOR]

Introduction: After a tooth extraction, the height of the buccal wall tends to decrease. The literature indicates that regenerative techniques (guided bone regenerative [GBR] techniques) have succeeded in improving the bone levels. Therefore, this experiment set out to compare the physiological bone remodelling in Beagle dog models after implant placement in a fresh extraction socket, with and without the application of regenerative procedure. Materials and methods: Five dogs were used in this study. Test and control sites were randomly selected. The experimental teeth (fourth pre-molar and first molar) were hemi-sected removing the distal roots and placing implants. Porcine bone was placed to fill the gap around the implant on the test sites and a reabsorbable membrane was used to cover the area. The dogs were put down at different times (2 weeks, 1 month and 3 months). The measurements were taken immediately and at 2, 4, 12 weeks after implant placement. Student's test for paired data was used to compare the means of the clinical measurements. Results: At 2 weeks: On the control sites, few signs of resorption were detected at the first molar only, while at the test sites bone levels were placed at the implant shoulder or above. At 4 weeks: On the control site, slight bone remodelling was observed, while on the test site minor signs of resorption or an increase of bone levels were detected. At 12 weeks: The alveolar crest on the control sites showed various degrees of remodelling. On the test sites stable bone levels or an increase of bone crest was observed. Conclusion: With the limits of this study, the findings showed that GBR techniques were able to limit resorption of the alveolar crest after tooth extraction. A pattern of bone remodelling after tooth extraction and implant placement was observed in the control sites (no GBR) as well as in test sites (GBR), and although the exact cause of this is unclear, surgical trauma could play a role. Further studies are necessary to confirm these results and to clarify the precise causes of bone remodelling in fresh extraction sockets. To cite this article: Barone A, Ricci M, Calvo-Guirado JL, Covani U. Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in the Beagle dogs. Clin. Oral Impl. Res. 22, 2011; 1131-1137 doi: 10.1111/j.1600-0501.2010.02084.x [ABSTRACT FROM AUTHOR]

To carry out a radiological and histomorphometric evaluation of bone response to bovine bone implants inserted in rabbits' tibiae. Twenty New Zealand rabbits weighing 3900-4500 g were used. Twenty bovine bone implants (Endobon) in granulated form of 500-1000 μm granulometry were inserted in the proximal metaphyseal area of the animals' right tibia and 20 control areas were located in the proximal metaphyseal area. Following implantation, the animals were sacrificed in four groups of five, after 1 month, 2 months, 3 months and 4 months, respectively. Anteroposterior and lateral radiographs were taken. Samples were sectioned at 5 μm and stained using Hematoxylin-Eosin and Masson's trichromic. After 4 months, radiological images showed complete repair of the bone defects. No healed or residual bone alterations attributable to the presence of the implant were observed. Histomorphometric analysis at 4 months showed the presence of a higher density of newly formed bone with mean values for new bone, residual graft material and non-mineralized connective tissue of 22.8 ± 1.5%, 39.4 ± 2.3% and 37.7 ± 2.5%. There were no statistically significant differences in the length of cortical formation with bovine bone, 98.8 ± 1.1%, compared with the control group, 99.1 ± 0.7%, at the end of the study period. The biomaterial used in the study was shown to be biocompatible, osteoconductive and non-resorbable and as such a possible bone substitute that does not interfere with normal reparative bone processes. Ramírez-Fernández MP, Calvo-Guirado JL, Delgado-Ruiz RA, Maté-Sánchez del Val JE, Gómez-Moreno G, Guardia J. Experimental model of bone response to xenografts of bovine origin (Endobon): a radiological and histomorphometric study. Clin. Oral Impl. Res. , 2011; 727-734 doi: 10.1111/j.1600-0501.2010.02052.x [ABSTRACT FROM AUTHOR]

To carry out a radiological and histomorphometric evaluation of bone response to two xenografts of animal origin, one porcine, and the other bovine, inserted in rabbits' tibiae. Twenty New Zealand rabbits weighing 3900-4500 g were used. Twenty bovine bone grafts (Endobon) in granulated form of 500-1000 μm granulometry were inserted in the proximal metaphyseal area of the animals' right tibia, and 20 porcine bone grafts (OsteoBiolmp3) in granulated form of 600-1000 μm granulometry were inserted in the proximal metaphyseal area of the animals' left tibia. Following graft insertion, the animals were sacrificed in four groups of five, after 1, 2, 3 and 4 months, respectively. Anteroposterior and lateral radiographs were taken. Samples were processed for observation under light microscopy. Histomorphometric measurements were presented as mean values ± standard deviations. At 4 months after treatment, the bone defects displayed radiological images that showed complete repair of osseous defects. Histomorphometric evaluation showed that for the porcine xenograft, the study averages for newly formed bone represented 22.8 ± 1.8%, for residual graft material 23.6 ± 3% and for connective tissue 53.5 ± 2.5%, while for the bovine xenograft newly formed bone represented 23.1 ± 1.8%, residual graft material 39.4 ± 3% and non-mineralized connective tissue 37.5 ± 2.5%. The biomaterials assessed in the study were shown to be biocompatible and osteoconductive. Collagenized porcine xenografts proved more resorbable than bovine xenografts. Both can be used as possible bone substitutes without interfering with normal reparative bone processes. Ramírez-Fernández MP, Calvo-Guirado JL, Delgado-Ruiz RA, Maté-Sánchez del Val JE, Vicente-Ortega V, Meseguer-Olmos L. Bone response to hydroxyapatites with open porosity of animal origin (porcine [OsteoBiolmp3] and bovine [Endobon]): a radiological and histomorphometric study. Clin. Oral Impl. Res. , 2011; 767-773. doi: 10.1111/j.1600-0501.2010.02058.x [ABSTRACT FROM AUTHOR]

The first objective of the present study was to compare the short- and long-term 3D volume stability of sub-sinusal bone regeneration in rabbits using different space fillers. The second objective was to assess qualitatively and quantitatively the early bone formation process and long-term behavior of the regenerated bone. Fifteen rabbits underwent a double sinus lift procedure using: blood clot (Clot), autogenous bone chips (Auto) and bovine hydroxyapatite (BHA). Animals were euthanized at 1 week, 5 weeks and 6 months. Samples were subjected to X-ray microtomography and histology. Variations in the volume of bone augmentations were calculated at different time points. Qualitative analysis was performed using 7 μm sections and quantitative histomorphometric analyses were carried out using scanning electron microscopy. From baseline (100%) to 5 weeks, the augmented volumes declined to 17.3% (Clot), 57.6% (Auto) and 90.6% (BHA). After 6 months, only 19.4% (Clot) and 31.4% (Auto) of initial volumes were found, while it remained more stable in the BHA group (84%). At 1 week, an initial osteogenesis process could be observed in the three groups along the bone walls. At 5 weeks, despite a significant decline in the volume, newly formed bone density was higher with Clot and Auto than with BHA. At 6 months, bone densities were statistically similar in the three groups. However, after 6 months, the surface invaded by newly formed bone (regenerated area) was significantly higher when BHA was used as space filler. In the BHA group, the biomaterial area slightly decreased from 42.7% (1 week) to 40% (5 weeks) and 34.9% (6 months) and the density of the composite regenerated tissue (bone+BHA) reached >50% at 6 months. The three space fillers allowed bone formation to occur. Nevertheless, augmented volumes declined in the Clot and Auto groups, while they remained stable with BHA. A slowly resorbable biomaterial might be suitable in sub-sinusal bone augmentation for preventing the re-expansion process and for augmenting the density of the regenerated tissues. Lambert F, Léonard A, Drion P, Sourice S, Layrolle P, Rompen E. Influence of space-filling materials in subantral bone augmentation: blood clot vs. autogenous bone chips vs. bovine hydroxyapatite. Clin. Oral Impl. Res. , 2011; 538-545 doi: 10.1111/j.1600-0501.2010.02069.x [ABSTRACT FROM AUTHOR]

Following tooth extraction and immediate implant installation, the edentulous site of the alveolar process undergoes substantial bone modeling and the ridge dimensions are reduced. The objective of the present experiment was to determine whether the process of bone modeling following tooth extraction and immediate implant placement was influenced by the placement of a xenogenic graft in the void that occurred between the implant and the walls of the fresh extraction socket. Five beagle dogs about 1 year old were used. The 4th premolar in both quadrants of the mandible (P) were selected and used as experimental sites. The premolars were hemi-sected and the distal roots removed and, subsequently, implants were inserted in the distal sockets. In one side of the jaw, the marginal buccal-approximal void that consistently occurred between the implant and the socket walls was grafted with Bio-Oss Collagen while no grafting was performed in the contra-lateral sites. After 6 months of healing, biopsies from each experimental site were obtained and prepared for histological analyses. The outline of the marginal hard tissue of the control sites was markedly different from that of the grafted sites. Thus, while the buccal bone crest in the grafted sites was comparatively thick and located at or close to the SLA border, the corresponding crest at the control sites was thinner and located a varying distance below SLA border. It was demonstrated that the placement of Bio-Oss Collagen in the void between the implant and the buccal-approximal bone walls of fresh extraction sockets modified the process of hard tissue healing, provided additional amounts of hard tissue at the entrance of the previous socket and improved the level of marginal bone-to-implant contact. Araújo MG, Linder E, Lindhe J. Bio-Oss Collagen in the buccal gap at immediate implants: a 6-month study in the dog. Clin. Oral Impl. Res. , 2011; 1-8. doi: 10.1111/j.1600-0501.2010.01920.x [ABSTRACT FROM AUTHOR]

Background: In previous short-term studies, it was observed that while the placement of biomaterial in alveolar sockets may promote bone formation and ridge preservation, the graft may in fact also delay healing. Aim: The objective of the present experiment was to evaluate the more long-term effect on hard tissue formation and the amount of ridge augmentation that can occur by the placement of a xenogeneic graft in extraction sockets of dogs. Material and methods: Five beagle dogs were used. The third mandibular premolars were hemi-sected. The distal roots were carefully removed. A graft consisting of Bio-Oss® collagen was placed in one socket while the contra-lateral site was left without grafting. After 6 months of healing, the dogs were euthanized and biopsies were sampled. From each experimental site, four ground sections – two from the mesial root and two from the healed socket – were prepared, stained and examined under a microscope. Results: The placement of Bio-Oss® collagen in the fresh extraction socket served as a scaffold for tissue modeling but did not enhance new bone formation. In comparison with the non-grafted sites, the dimension of the alveolar process as well as the profile of the ridge was better preserved in Bio-Oss®-grafted sites. Conclusion: The placement of a biomaterial in an extraction socket may modify modeling and counteract marginal ridge contraction that occurs following tooth removal. [ABSTRACT FROM AUTHOR]

Smokers are more susceptible than non-smokers to persistent infection by Porphyromonas gingivalis, a causative agent of periodontitis. Patients who smoke exhibit increased susceptibility to periodontitis and are more likely to display severe disease and be refractory to treatment. Paradoxically, smokers demonstrate reduced clinical inflammation. We show that P. gingivalis cells exposed to cigarette smoke extract (CSE) induce a lower proinflammatory response (tumour necrosis factor-α, interleukin-6, interleukin-12 p40) from monocytes and peripheral blood mononuclear cells than do unexposed bacteria. This effect is reversed when CSE-exposed bacteria are subcultured in fresh medium without CSE. Using microarrays representative of the P. gingivalis genome, CSE-exposure resulted in differential regulation of 6.8% of P. gingivalis genes, including detoxification and oxidative stress-related genes; DNA repair genes; and multiple genes related to P. gingivalis virulence, including genes in the major fimbrial and capsular operons. Exposure to CSE also altered the expression of outer membrane proteins, most notably by inducing the virulence factors RagA and RagB, and a putative lipoprotein cotranscribed with the minor fimbrial antigen. Therefore, CSE represents an environmental stress to which P. gingivalis adapts by altering gene expression and outer membrane proteins. These changes may explain, in part, the altered virulence and host–pathogen interactions that have been documented in vivo in smokers with periodontal disease. [ABSTRACT FROM AUTHOR]

Objective: To histomorphometrically investigate the repair of critical size defects (CSDs) and bone augmentation in cranial walls using block of sintered bovine-derived anorganic bone (sBDAB) graft. Material and methods: Forty guinea-pigs were divided into test ( n=20) and CSD control ( n=20) groups. In each animal, a full-thickness bone defect with 9.5 mm diameter was made in the frontal bone. The defects were filled with an sBDAB block soaked in blood in the test group and with blood clot in the CSD control group. The skulls were collected at 0 h ( n=2) and 30, 90 and 180 days ( n=6/group and period) postoperatively. The volume density and total volume of newly formed bone, sBDAB, blood vessels and connective tissue, vertical thickness of removed bone plug, sBDAB block and graft area were evaluated. Results: The vertical thickness of the adapted sBDAB block was 3.8 times higher than that of the removed bone plug and did not show significant difference between periods, filling in average 29.8% of the total graft region. The sBDAB block exhibited complete osseointegration with the borders of the defect at 90 days. At 90 and 180 days, the vertical thickness of the graft was 279% in the average, and the total volume of bone augmentation was, respectively, 78.8% and 148.5% higher compared with the removed bone plug. The defects of the CDS control group showed limited osteogenesis and filling by connective tissue plus tegument. Conclusion: The sBDAB block can be used to promote repair of CSDs and bone augmentation in the craniomaxillofacial region, due to its good osteoconductive and slow resorptive properties. [ABSTRACT FROM AUTHOR]

Purpose: In this prospective study, solid monocortical iliac onlay grafts of the maxilla were randomly covered with a bioresorbable membrane and periosteum within the maxilla. Histologic specimens were analyzed by light microscopy after a healing period of three months and the rate of resorption of the grafts were measured. Materials and methods: Fourteen patients (9 females and 5 males), with a mean age of 56 years (range 25–72) underwent augmentation with avascular iliac onlay bone grafts. The grafts were randomly covered either with a bioresorbable membrane (MC) or periosteum (PC). Resorption was measured with a digital caliper at the microscrews (∅1.5 mm) used to fixate the graft. Histologic evaluation of the specimens derived from the graft with a trephine bur (∅2 mm) from the implant site at implant placement after a 3-month healing period. Statistical evaluation of the data was performed using Analysis of variance and the Wilcoxon signed rank test. Results: Clinical appearance of the augmented bone after 3 months showed a dense cortical layer with good vascular perfusion. Thirty-three sites in 13 patients (one dropped put) were analyzed histomorphometrically and showed an average of 46% newly formed bone with no significant difference between the groups ( P=0.46). The mean resorption rate at 56 measured sites was 1.2 mm (range 0.3–3.4 mm) after 3 months, with no significant difference between the MC sites and the PC sites ( P=0.38). Discussion: Histomorphometry of new bone formation after 3 months demonstrates no significant difference between the PC and MC groups. Initialization of graft resorption can be seen after 3 months with no significant difference as to whether the graft was covered with a membrane or the periosteum. Conclusion: This study provides evidence that after avascular iliac bone grafting, the revascularization of the graft was sufficient after 3 months regardless of the graft coverage with no effect on the amount of initial resorption of the graft. [ABSTRACT FROM AUTHOR]

The article presents a prospective study which focuses on the histomorphometric analysis of human extraction socket that has been augmented with Bio-Oss Collagen after a healing period of six weeks. Results of the study show equivalent time points for the formation of bone in unfilled extraction sockets in humans.

Objective: The aim of this retrospective investigation was to assess the dimensional stability of different grafting materials after maxillary sinus floor augmentation with computed tomography (CT) scans. Materials and methods: Two postoperative CT scans were available from 16 patients who had undergone maxillary sinus lift procedures. The first scan was made within a few days after the surgical intervention and the second one >6 months later. A total of 25 maxillary sinuses were augmented with different materials before implant insertion by lateral antrostomy in a staged approach. The volume of bone formation was calculated using the Somaris® Sienet Magic View software. Results: Based on volumetric measurements of the augmented domes derived from the image sections, shrinkage was about 26%. The mean of the augmented bone volume was 3.02 cm3 (1.4–5.56 cm3; SD±1.18 cm3) as determined in the first CT scan. The respective mean volume in the second CT scan amounted to 2.28 cm3 (0.92–4.46 cm3; SD±1.07 cm3). Conclusion: Within the limits of our descriptive and analytic study, the results indicate a significant reduction of the graft volume after maxillary sinus augmentation. Further prospective studies will have to evaluate the quantitative changes of different bone graft materials for maxillary sinus augmentation procedures in order to improve long-term implant stability. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this study was to evaluate (i) the degree of bone mineralization in the alveolar sockets 3 months following the use of a bio-absorbable graft material and (ii) the degree of resorption of the grafted material. Materials: Twenty patients, undergoing periodontal therapy, participated in this study. All patients were scheduled for extraction of one or more compromised monoradicular teeth and scheduled for replacement of the extracted teeth with dental implants. Methods: Following elevation of full-thickness flaps and extraction of teeth, the alveolar sockets were filled with a bioabsorbable polylactide–polyglycolide acid sponge (Fisiograft®) (Test group – T) or natural healing by clot formation was allowed (Control group – C). The flaps were sutured with no attempt to achieve primary closure of the surgical wound. Re-entry for implant surgery was performed 3 months following the extractions. Results: Fifteen biopsies (seven T and nine C) were harvested from the sites where the implants were placed. The biopsies harvested from the T sites revealed that the alveolar sockets healed with newly trabecular bone, highly mineralized and well structured. Particles of the grafted material could not be identified in any of the T biopsies. The bone formed in the C sites was also well structured, with a slightly minor percentage of mineralized bone. In both T and C biopsies, the apical portion presented a higher degree of mineralization compared with the coronal portion. Conclusions: The results of this study indicated that the use of a bio-absorbable synthetic sponge of polylactide–polyglycolide acid did not interfere with the formation of new bone in the alveolar sockets and that the characteristics of the 3-month newly formed bone seemed to be optimal for dental implants' insertion. The biocompatibility, safety and characteristics of Fisiograft® suggest that the material is suitable for filling alveolar sockets following extractions, to prevent volume reduction and collapse of the overlying soft tissue flaps. [ABSTRACT FROM AUTHOR]

Objectives: This study evaluated key parameters of the in vitro osteogenesis induced by osteoblastic cells obtained from sites submitted to sinus grafting with anorganic bovine bone (ABB) in comparison with cells derived from bone sites of the same patients. Materials and methods: In three patients, the augmentation of maxillary sinus was carried out using ABB (Bio-Oss®). After at least 6 months, during the surgical intervention for titanium implants placement, biopsies were taken from these areas using trephine burs (grafted group). Bone fragments, of the same patients, from sites that had not received graft were also obtained with trephine burs and used as a control group. Osteoblastic cells were obtained from grafted and control groups by enzymatic digestion and cultured under standard osteogenic condition until subconfluence. First passaged cells were cultured in 24-well culture plates. Cell adhesion was evaluated at 24 h. For proliferation and viability assay, cells were cultured for 1, 3, 7, and 10 days. Total protein content and alkaline phosphatase (ALP) activity were measured at 3, 7, 10, 14, 17, and 21 days. Cultures were stained with Alizarin red S at 21 days, for detection of mineralized matrix. Data were compared by Student's t-test. Results: Cell adhesion and viability were not affected by cell source ( P>0.05). Total protein content was greater ( P<0.05) for grafted group. Cell proliferation, ALP activity, and bone-like nodule formation were all greater ( P<0.05) for the control group. Conclusion: Taken together, these results indicate that the in vivo long-term contact of cells with ABB downregulates the expression of osteoblast phenotype and consequently the in vitro osteogenesis. [ABSTRACT FROM AUTHOR]

Objective: To analyze the clinical outcome of horizontal ridge augmentation using autogenous block grafts covered with anorganic bovine bone mineral (ABBM) and a bioabsorbable collagen membrane. Material and methods: In 42 patients with severe horizontal bone atrophy, a staged approach was chosen for implant placement following horizontal ridge augmentation. A block graft was harvested from the symphysis or retromolar area, and secured to the recipient site with fixation screws. The width of the ridge was measured before and after horizontal ridge augmentation. The block graft was subsequently covered with ABBM and a collagen membrane. Following a tension-free primary wound closure and a mean healing period of 5.8 months, the sites were re-entered, and the crest width was re-assessed prior to implant placement. Results: Fifty-eight sites were augmented, including 41 sites located in the anterior maxilla. The mean initial crest width measured 3.06 mm. At re-entry, the mean width of the ridge was 7.66 mm, with a calculated mean gain of horizontal bone thickness of 4.6 mm (range 2–7 mm). Only minor surface resorption of 0.36 mm was observed from augmentation to re-entry. Conclusions: The presented technique of ridge augmentation using autogenous block grafts with ABBM filler and collagen membrane coverage demonstrated successful horizontal ridge augmentation with high predictability. The surgical method has been further simplified by using a resorbable membrane. The hydrophilic membrane was easy to apply, and did not cause wound infection in the rare instance of membrane exposure. [ABSTRACT FROM AUTHOR]

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The aim of this study was to determine interleukin-1β (IL-1β), tumor necrosis factor-α (TNF-α) levels and neutrophil elastase (NE) activity in peri-implant crevicular fluid (PICF) of smoker and nonsmoker patients, and to investigate their relationships with clinical parameters. A total of 42 endosseous root-form dental implants of 14 patients were clinically examined by modified Plaque index (PI), modified Gingival index (GI) and probing depth (PD). Smoking habits of the patients were recorded. PICF of implants were collected by Periopaper strips and IL-1β, TNF-α levels were determined by enzyme-linked immunosorbent assay (ELISA). NE was analyzed with a neutrophil specific chromogenic substrate, N -methoxysuccinyl-Ala-Ala-Pro-Val-p-nitroanilide. The cytokine and enzyme levels in PICF were expressed as total amount/activity and as concentrations. NE activity in PICF significantly correlated with GI and PD, and IL-1β levels with GI and PICF volume (P < 0.05). The correlations were stronger when the PICF levels were expressed as total IL-1β amount and as total NE activity. The implants with inflamed gingiva (GI > 1) had higher levels of IL-1β and NE activity than implants with noninflamed or slightly inflamed gingiva (GI ≤ 1) (P < 0.05). Total NE activity in implants with deep pockets (PD > 3 mm) was greater than the implants with shallow pockets (PD ≤ 3 mm) (P < 0.05). The implants of smoker patients had significantly lower PICF NE activity and IL-1β levels, and significantly higher TNF-α levels than the implants of nonsmokers (P < 0.05). The findings of the present study indicate that NE activity and IL-1β levels in PICF may be used to measure implant health status of patients who do not smoke. [ABSTRACT FROM AUTHOR]

Presents an index of authors of articles published in the August 1998 issue of the "Journal of Oral Pathology and Medicine."