Oral implants placed in bone defects treated with Bio-Oss, Ostim-Paste or PerioGlas: an experimental study in the rabbit tibiae

OBJECTIVES: To compare the histological features of bone filled with Bio-Oss, Ostim-Paste or PerioGlas placed in defects in the rabbit tibiae by evaluating bone tissue composition and the integration of titanium implants placed in the grafted bone. MATERIAL AND METHODS: Two cylindrical bone defects, about 4 mm in diameter and 6 mm in depth, were created in the tibiae of 10 rabbits. The defects were filled with either Bio-Oss, PerioGlas, Ostim-Paste or left untreated, and covered with a collagen membrane. Six weeks later, one titanium sandblasted and acid-etched (SLA) implant was inserted at the centre of each previously created defect. The animals were sacrificed after 6 weeks of healing. RESULTS: Implants placed in bone previously grafted with Bio-Oss, PerioGlas or Ostim-Paste obtained a larger extent of osseointegration, although not statistically significant, than implants placed in non-grafted bone. The three grafting materials seemed to perform in a similar way concerning their contribution towards implant osseointegration. All grafting materials appeared to be osteoconductive, thus leading to the formation of bridges of mineralized bone extending from the cortical plate towards the implants surface through the graft scaffold. CONCLUSIONS: Grafting with the above-mentioned biomaterials did not add any advantage to the osseointegration of titanium SLA implants in a self-contained defect.

Histological evaluation of human intrabony periodontal defects treated with an unsintered nanocrystalline hydroxyapatite paste

OBJECTIVES The aim of the study was to clinically and histologically evaluate the healing of human intrabony defects treated with open flap surgery (OFD) and application of a new, resorbable, fully synthetic, unsintered, nanocrystalline, phase-pure hydroxyapatite (nano-HA). MATERIALS AND METHODS Six patients, each of them displaying very advanced intrabony defects around teeth scheduled for extraction due to advanced chronic periodontitis and further prosthodontic considerations, were included in the study. Following local anaesthesia, mucoperiosteal flaps were reflected; the granulation tissue was removed, and the roots were meticulously debrided by hand and ultrasonic instruments. A notch was placed at the most apical extent of the calculus present on the root surface or at the most apical part of the defect (if no calculus was present) in order to serve as a reference for the histological evaluation. Following defect fill with nano-HA, the flaps were sutured by means of mattress sutures to allow primary intention healing. At 7 months after regenerative surgery, the teeth were extracted together with some of their surrounding soft and hard tissues and processed for histological analysis. RESULTS The postoperative healing was uneventful in all cases. At 7 months following surgery, mean PPD reduction and mean CAL gain measured 4.0 ± 0.8 and 2.5 ± 0.8 mm, respectively. The histological analysis revealed a healing predominantly characterized by epithelial downgrowth. Limited formation of new cementum with inserting connective tissue fibers and bone regeneration occurred in three out of the six biopsies (i.e. 0-0.86 and 0-1.33 mm, respectively). Complete resorption of the nano-HA was found in four out of the six biopsies. A few remnants of the graft particles (either surrounded by newly formed mineralized tissue or encapsulated in connective tissue) were found in two out of the six biopsies. CONCLUSION Within their limits, the present results indicate that nano-HA has limited potential to promote periodontal regeneration in human intrabony defects. CLINICAL RELEVANCE The clinical outcomes obtained following surgery with OFD + nano-HA may not reflect true periodontal regeneration.

Effectiveness of a calcium sodium phosphosilicate-containing prophylaxis paste in reducing dentine hypersensitivity immediately and 4 weeks after a single application: a double-blind randomized controlled trial

AIMS The aim of this single-site, randomized, controlled, double-blind, 3-arm parallel study was to determine the effectiveness of a prophylaxis paste containing 15% calcium sodium phosphosilicate (CSPS; NovaMin(®) ) with and without fluoride in reducing dentine hypersensitivity immediately after a single application and 28 days following dental scaling and root planing. MATERIALS & METHODS Overall, 151 subjects were enrolled in this study. All subjects received a scaling and root planing procedure followed by a final prophylaxis step using one of three different prophylaxis pastes: Test-A (15% NovaMin(®) and NaF), Test-B (15% NovaMin(®) ) and a control. Dentine hypersensitivity was assessed by tactile stimulus (Yeaple Probe(®) ) and by air blast (Schiff scale) at baseline, immediately after and 28 days after a prophylaxis procedure. One hundred and forty-nine subjects completed the study. RESULTS Subjects having received the test prophylaxis pastes showed statistically lower (anova, p < 0.05) dentine hypersensitivity compared with the control group immediately after the prophylaxis procedure (Yeaple Probe(®) : Test-A = 20.9 ± 12.6, Test-B = 22.7 ± 12.9, Control=11.2 ± 3.1; Schiff score: Test-A = 1.1 ± 0.6, Test-B = 1.1 ± 0.6, Control = 2.0 ± 0.7) and after 28 days (Yeaple probe: Test-A = 21.5 ± 11.9, Test-B = 20.6 ± 11.3, Control = 11.8 ± 6.0; Schiff score: Test-A = 1.0 ± 0.6, Test-B = 1.0 ± 0.6, Control = 2.0 ± 0.7). CONCLUSIONS In conclusion, the single application of both fluoridated and non-fluoridated prophylaxis pastes containing 15% CSPS (NovaMin(®) ) provided a significant reduction of dentine hypersensitivity up to at least 28 days.

Influence of different professional prophylactic methods on fluorescence measurements for detection of occlusal caries

This study aimed to evaluate the influence of professional prophylactic methods on the DIAGNOdent 2095, DIAGNOdent 2190 and VistaProof performance in detecting occlusal caries. Assessments were performed in 110 permanent teeth at baseline and after bicarbonate jet or prophylactic paste and rinsing. Performance in terms of sensitivity improved after rinsing of the occlusal surfaces when the prophylactic paste was used. However, the sodium bicarbonate jet did not significantly influence the performance of the fluorescence-based methods. It can be concluded that different professional prophylactic methods can significantly influence the performance of fluorescence-based methods for occlusal caries detection.

Preventing erosion with novel agents

Objectives: This in vitro study aimed to investigate the protective effect of four commercial novel agents against erosion. Methods: Ninety human molars were distributed into 9 groups, and after incubation in human saliva for 2 h, a pellicle was formed. Subsequently, the specimens were submitted to demineralization (orange juice, pH 3.6, 3 min) and remineralization (paste slurry containing one of the tested novel agents, 3 min) cycles, two times per day, for 4 days. The tested agents were: (1) DenShield Tooth; active ingredient: 7.5% W/W NovaMin® (calcium sodium phosphosilicate); (2) Nanosensitive hca; active ingredient: 7.5% W/W NovaMin®; (3) GC Tooth Mousse; active ingredient: 10% Recaldent™ (CPP-ACP); (4) GC MI Paste Plus; active ingredients: 10% Recaldent™, 900 ppm fluoride. Two experimental procedures were performed: in procedure 1, the tested agents were applied prior to the erosive attack, and in procedure 2 after the erosive attack. A control group receiving no prophylactic treatment was included. Surface nanohardness (SNH) of enamel specimens was measured after pellicle formation and after completion of daily cyclic treatment. Results: SNH significantly decreased at the end of the experiment for all groups (p < 0.05). In both procedures, there was no statistically significant difference between the control group and those treated with paste slurries (p > 0.05). In addition, the changes in SNH (ΔSNH = SNHbaseline − SNHfinal) did not show statistically significant difference between both procedures (p > 0.05). Conclusion: Tooth erosion cannot be prevented or repaired by these novel agents, regardless of fluoride content.

Intra-articular calcium phosphate cement: Its fate and impact on joint tissues in a rabbit model

Clinical application of injectable ceramic cement in comminuted fractures revealed penetration of the viscous paste into the joint space. Not much is known on the fate of this cement and its influence on articular tissues. The purpose of this experimental study was to assess these unknown alterations of joint tissues after intra-articular injection of cement in a rabbit knee. Observation periods were from 1 week up to 24 months, with three rabbits per group. Norian SRS cement was injected into one knee joint, the contralateral side receiving the same volume of Ringers' solution. Light microscopic evaluation of histologic sections was performed, investigating the appearance of the cement, inflammatory reactions, and degenerative changes of the articular surface. No signs of pronounced acute or chronic inflammation were visible. The injected cement was mainly found as a single particle, anterior to the cruciate ligaments. It became surrounded by synovial tissues within 4 weeks and showed signs of superficial resorption. In some specimens, bone formation was seen around the cement. Degeneration of the articular surface showed no differences between experimental and control side, and no changes over time became apparent. No major degenerative changes were induced by the injected cement. The prolonged presence of cement still seems to make it advisable to remove radiologically visible amounts from the joint space.

How Developers Copy

Copy-paste programming is dangerous as it may lead to hidden dependencies between different parts of the system. Modifying clones is not always straight forward, because we might not know all the places that need modification. This is even more of a problem when several developers need to know about how to change the clones. In this paper, we correlate the code clones with the time of the modification and with the developer that performed the modification to detect patterns of how developers copy from one another. We develop a visualization, named Clone Evolution View, to represent the evolution of the duplicated code. We show the relevance of our approach on several large case studies and we distill our experience in forms of interesting copy patterns.

Influence of hemostatic agents upon the outcome of periapical surgery: dressings with anesthetic and vasoconstrictor or aluminum chloride

OBJECTIVE To evaluate the effects of different hemostatic agents upon the outcome of periapical surgery. DESIGN A retrospective study was made of patients subjected to periapical surgery between 2006-2009 with the ultrasound technique and using MTA as retrograde filler material. We included patients with a minimum follow-up of 12 months, divided into two groups according to the hemostatic agent used: A) dressings impregnated in anesthetic solution with adrenalin; or B) aluminum chloride paste (Expasyl). Radiological controls were made after 6 and 12 months, and on the last visit. The global evolution scale proposed by von Arx and Kurt (1999) was used to establish the outcome of periapical surgery. RESULTS A total of 96 patients (42 males and 54 females) with a mean age of 40.7 years were included. There were 50 patients in the aluminum chloride group and 46 patients in the anesthetic solution with vasoconstrictor group. No significant differences were observed between the two groups in terms of outcome after 12 months - the success rate being 58.6% and 61.7% in the anesthetic solution with vasoconstrictor and aluminum chloride groups, respectively (p > 0.05). CONCLUSION The outcome after 12 months of follow-up was better in the aluminum chloride group than in the anesthetic solution with vasoconstrictor group, though the difference was not significant.

Osteocyte lacunar density and area in newly formed bone of the augmented sinus

OBJECTIVES Osteocytes, the most common cells of the bone, are buried in lacunae. Density and area of the osteocyte lacunae change with increasing maturation of the newly formed bone. Evaluation of osteocyte lacunae can therefore provide insights into the process of graft consolidation. MATERIALS AND METHODS Here, we determined the osteocyte lacunar density (number of osteocyte lacunae per bone area; N.Ot/BAr) and the osteocyte lacunar area in μm(2) (Lac.Ar) in histological specimens 6 and 12 weeks after the sinuses of 10 minipigs were augmented with Bio-Oss(®) , a deproteinized bovine bone mineral, and Ostim(®) , an aqueous paste of synthetic nanoparticular hydroxyapatite. The region of interest was defined by the following criteria: (i) >1 mm from the host bone, (ii) >0.5 mm from the sinus mucosa, (iii) minimum area of 0.2 mm(2) , and (iv) bone tissue spanning at least two bone substitute particles. RESULTS The overall osteocyte lacunar density was significantly higher in the Bio-Oss(®) group than in the Ostim(®) group and decreased during the observation period at a similar range in both groups. The osteocyte lacunar area was smaller in the Bio-Oss(®) group than the Ostim(®) group but there was no significant change within the groups over time. CONCLUSIONS These results suggest that bone substitutes affect the osteocyte lacunar density and the osteocyte lacunar area in the newly formed bone within the augmented sinus in this particular model situation. These measures can provide insights into the maturation of newly formed bone in the augmented sinus.

Effect of pulverized natural bone mineral on regeneration of three-wall intrabony defects. A preclinical study.

AIMS The objective of this study is to evaluate the effects of a paste-like bone substitute material with easy handling properties and improved mechanical stability on periodontal regeneration of intrabony defects in dogs. MATERIALS AND METHODS Mandibular and maxillary first and third premolars were extracted, and three-wall intrabony defects were created on second and fourth premolars. After a healing period of 3 months, acute type defects were filled with a paste-like formulation of deproteinized bovine bone mineral (DBBM) (particle size, 0.125-0.25 mm) in a collagenous carrier matrix (T1), pulverized DBBM (particle size, 0.125-0.25 mm) without the carrier (T2), or Bio-Oss® granules (particle size, 0.25-1.00 mm) as control (C). All defects were covered with a Bio-Gide® membrane. The dogs were sacrificed after 12 weeks, and the specimens were analyzed histologically and histometrically. RESULTS Postoperative healing of all defects was uneventful, and no histological signs of inflammation were observed in the augmented and gingival regions. New cementum, new periodontal ligament, and new bone were observed in all three groups. The mean vertical bone gain was 3.26 mm (T1), 3.60 mm (T2), and 3.81 mm (C). That of new cementum was 2.25 mm (T1), 3.88 mm (T2), and 3.53 mm (C). The differences did not reach statistical significance. The DBBM particles were both incorporated in new bone and embedded in immature bone marrow. CONCLUSIONS The results of this preclinical study showed that the 0.125-0.25-mm DBBM particles in a powder or paste formulation resulted in periodontal regeneration comparable to the commercially available DBBM. Osteoconductivity, in particular, was not affected by DBBM size or paste formulation. CLINICAL RELEVANCE The improved handling properties of the paste-like bone substitute consisting of small DBBM particles embedded in a collagen-based carrier hold promise for clinical applications.

Ruler Based Automatic C-Arm Image Stitching Without Overlapping Constraint

In this paper, we propose a new method for stitching multiple fluoroscopic images taken by a C-arm instrument. We employ an X-ray radiolucent ruler with numbered graduations while acquiring the images, and the image stitching is based on detecting and matching ruler parts in the images to the corresponding parts of a virtual ruler. To achieve this goal, we first detect the regular spaced graduations on the ruler and the numbers. After graduation labeling, for each image, we have the location and the associated number for every graduation on the ruler. Then, we initialize the panoramic X-ray image with the virtual ruler, and we “paste” each image by aligning the detected ruler part on the original image, to the corresponding part of the virtual ruler on the panoramic image. Our method is based on ruler matching but without the requirement of matching similar feature points in pairwise images, and thus, we do not necessarily require overlap between the images. We tested our method on eight different datasets of X-ray images, including long bones and a complete spine. Qualitative and quantitative experiments show that our method achieves good results.

Influence of root canal disinfectants on growth factor release from dentin

INTRODUCTION During dentinogenesis, growth factors become entrapped in the dentin matrix that can later be released by demineralization. Their effect on pulpal stem cell migration, proliferation, and differentiation could be beneficial for regenerative endodontic therapies. However, precondition for success, as for conventional root canal treatment, will be sufficient disinfection of the root canal system. Various irrigation solutions and intracanal dressings are available for clinical use. The aim of this study was 2-fold: to identify a demineralizing solution suitable for growth factor release directly from dentin and to evaluate whether commonly used disinfectants for endodontic treatment will compromise this effect. METHODS Dentin disks were prepared from extracted human teeth and treated with EDTA or citric acid at different concentrations or pH for different exposure periods. The amount of transforming growth factor-β1 (TGF-β1), fibroblast growth factor 2, and vascular endothelial growth factor were quantified via enzyme-linked immunosorbent assay and visualized by gold labeling. Subsequently, different irrigation solutions (5.25% sodium hypochloride, 0.12% chlorhexidine digluconate) and intracanal dressings (corticoid-antibiotic paste, calcium hydroxide: water-based and oil-based, triple antibiotic paste, chlorhexidine gel) were tested, and the release of TGF-β1 was measured after a subsequent conditioning step with EDTA. RESULTS Conditioning with 10% EDTA at pH 7 rendered the highest amounts of TGF-β1 among all test solutions. Fibroblast growth factor 2 and vascular endothelial growth factor were detected after EDTA conditioning at minute concentrations. Irrigation with chlorhexidine before EDTA conditioning increased TGF-β1 release; sodium hypochloride had the opposite effect. All tested intracanal dressings interfered with TGF-β1 release except water-based calcium hydroxide. CONCLUSIONS Growth factors can be released directly from dentin via EDTA conditioning. The use of disinfecting solutions or medicaments can amplify or attenuate this effect.