Experimental Study In Beagle Dog Research Articles

Retraction Note: Narrow- versus mini-implants at crestal and subcrestal bone levels. Experimental study in beagle dogs at three months.

Retraction Note: Narrow- versus mini-implants at crestal and subcrestal bone levels. Experimental study in beagle dogs at three months.

Morphological and histological changes in the urethra after intraurethral nonablative erbium YAG laser therapy: an experimental study in beagle dogs

The purpose of this study was to investigate the morphological and histological changes in the urethra in beagle dogs after intraurethral Er:YAG laser irradiation in nonablative mode to confirm the safety of this therapy. Six 2-year-old healthy female virgin beagle dogs (13 ± 1.51 kg) were used in this study. The animals were divided into 2 groups: the sham group, which received sham treatment (n = 3) involving insertion of an intraurethral cannula and laser delivery handpiece into the urethra without laser irradiation, and the experimental group (n = 3), which received intraurethral Er:YAG laser irradiation. The laser irradiation parameters were set according to clinical criteria (4 mm spot size, 1.5 J/cm2, 1.4 Hz, and 4 pulses) in nonablative mode. All animals received three sequential sessions at 4-week intervals. Urethrography and urethroscopy were performed in the 12th week and 13th week, respectively, after the first treatment. After urethroscopy, the animals were sacrificed, and urethral tissue was harvested for histological investigations. All procedures were performed under general anesthesia (40 mg/kg 3% sodium pentobarbital, i.v.). Transforming growth factor β1 (TGF-β1) and α-smooth muscle actin (α-SMA) expression levels were measured to evaluate the biochemical characteristics of the scar. Urethral stricture was not found by urethrography or urethroscopy in either group. Urethral epithelium thickness and collagen expression under the urethral mucosa were significantly increased in the experimental group compared with the sham group. However, there were no significant differences in TGF-β1 and α-SMA expression between the experimental group and sham group (p > 0.05). Urethral stricture is not found in beagle dogs after clinically relevant intraurethral nonablative mode Er:YAG laser irradiation. Proliferation of urethral collagen and the urethral mucosa may be one of the mechanisms by which urine leakage symptoms can be improved.

Improvement in Osseointegration of Titanium Dental Implants After Exposure to Ultraviolet-C Light for Varied Durations: An Experimental Study in Beagle Dogs

Ultraviolet-mediated photofunctionalization is a valid technology for enhancing the osseointegration of titanium implants. However, there is no consensus on the effective exposure time to ultraviolet light. The objective of this study was to evaluate the effect of different exposure times of ultraviolet-C (UVC) light on aged titanium implants and explore the optimal treatment duration of UVC photofunctionalization for osseointegration in an animal model. Eight male beagle dogs (n=48) were divided into a control group (n=12) and 3 experimental groups (n=12/12/12) which received 4-week-old implants without UVC treatment (C) or treated with UVC for 1/6hour, 1/2hour, and 1hour (UVC-1/6hour, UVC-1/2hour, UVC-1hour) immediately before placement. All the implants were placed 12weeks after mandibular premolars extraction. Four dogs were euthanized after 4 and 12weeks of healing, respectively. The marginal bone level and implant stability quotient were measured at implant placement and after sacrifice. Subsequently, micro-CT and histomorphometric analyses were performed following block harvesting. No significant difference in marginal bone loss between the UVC-untreated and UVC-treated groups was found at 4 or 12weeks. At 4weeks, significantly higher BV/TV and bone-implant contact were observed in the UVC groups than in the C group, irrespective of the UVC-photofunctionalization duration (BV/TV: UVC-1/6hour 0.48±0.11, UVC-1/2hour 0.50±0.06, and UVC-1hour 0.47±0.08, C 0.34±0.04; bone-implant contact : UVC-1/6hour 84.30±5.02%, UVC-1/2hour 85.82±5.05%, and UVC-1hour 84.98±3.86%, C 71.69±3.52%. P<.05), whereas, no significant difference was observed among the UVC groups. At 12weeks, there were no significant differences between the C group and UVC groups. After 4 and 12weeks of healing, no significant difference in implant stability quotient values was observed between the C group and UVC groups. UVC photofunctionalization improved the early osseointegration of aged titanium implants. However, the effect was not dependent on the UVC-light duration within the range from 1/6hour to 1hour.

RETRACTED: Experimental Study on the Influence of Apigenin K and Melatonin in Socket Preservation as Bone Stimulators: An Experimental Study in Beagle Dogs

The aim is to evaluate whether apigenin K and melatonin M5250 were able to stimulate bone formation after tooth extraction at one, two, and three months follow-up. Six male beagle dogs were used. Apigenin K and melatonin M5250 immersed in hemostatic collagen sponges were placed in the third and fourth premolar and the first molar extracted sockets; the second premolar was used as control. At one, two, and three months, bone core biopsies were performed, and picrosirius–hematoxylin was used for the staining process. In the first month, a higher amount of calcified bone tissue was observed in the melatonin (77.87% ± 1.2%) and apigenin K (69.81% ± 1.8%) groups than the control group (57.27% ± 0.54%), with apparent discrepancies in values between the three groups (p &lt; 0.04). In the second month, there was a considerable improvement in the results in the areas with melatonin (79.81% ± 0.11%) than in those of apigenin K (71.65% ± 0.52%) and control (64.77% ± 0.44%) (p &lt; 0.04). In the third month, the number of mature bone was similar to all the groups. The creation of new bone was significant in the melatonin group (82.78% ± 0.87%), followed by the apigenin K group (78.76% ± 0.43%) and the control group (57.27% ± 0.11%). From this experimental study in dogs, it can be concluded that melatonin and apigenin K can accelerate the process of mineralization of the bone matrix, and thus the creation of laminae in the early stages of healing (1 month). Less reabsorption of the post-extraction sockets can be expected with the topical application of melatonin and apigenin K. It seems that the stimulatory effects of bone healing induced by the topical application of melatonin and apigenin K are defect-size-dependent, being more evident in small defects compared to larger defects.

Effect of natural bovine bone with and without EMD liquid (Osteogain) on implants with buccal bone defects‐ an experimental study in beagle dogs

Effect of natural bovine bone with and without EMD liquid (Osteogain) on implants with buccal bone defects‐ an experimental study in beagle dogs

Enamel matrix derivative in liquid form as adjunct to natural bovine bone grafting at buccal bone dehiscence defects at implant sites: An experimental study in beagle dogs.

To evaluate the effect of enamel matrix derivative in liquid form (EMD-liquid) as adjunct to grafting with natural bovine bone (NBB), on new bone formation and osseointegration in buccal dehiscence defects at dental implants. In six beagles, 3months after extraction of the mandibular premolars and first molars. Three titanium implants (3.3Ø×8.0mm) were inserted, and dehiscence-type defects (mesiodistal width 3mm×5mm depth) were created on their buccal aspect. The defects were randomly assigned to one of the following three treatment groups: Group 1: NBB, Group 2: NBB/EMD-L, Group 3: Control. All sites were covered with a collagen membrane. Histomorphometric measurements were performed after 3months of healing. New bone area, bone-to-implant contact (BIC), and first BIC (fBIC) in the NBB and NBB/EMD-L groups were significantly greater than in the control group (p<.05). Further, f-BIC was at a significantly more coronal position in the NBB+EMD-liquid group (0.4±0.1mm) compared with the NBB group (1.2±0.2mm). Natural bovine bone grafting enhances bone regeneration and osseointegration at implants with buccal bone dehiscences compared with no grafting, and adjunct use of EMD-liquid appears to further enhance bone formation and osseointegration.

Changes of Microbial Community in Treated Peri-implantitis Sites: An Experimental Study in Beagle Dogs.

To investigate the changes of the bacterial community in the oral environment of beagle dogs to gain insights on the possible causes of failed therapy in peri-implantitis. Beagles were used as models for experimental peri-implantitis. Samples from peri-implant soft tissue (supramargin and submargin), ligature and contaminated surface of peri-implantitis sites were collected and analysed by sequencing the bacterial 16S rRNA gene. The residual microbial community from the curettes-treated implant surface contained a variety of microorganisms, including periodontal pathogens, which showed no changes in their composition and structure. It is possible that the residual bacterial community remained unchanged and this was the cause of recurrent episodes of inflammation.

Soft tissue healing of immediate and delayed implants. An experimental study in beagle dogs.

Soft tissue healing of immediate and delayed implants. An experimental study in beagle dogs.

Retraction.

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 Beagle dogs. Clin Oral Impl Res. 2011;22: 1131-1137. The above article, published online on 20 January 2011 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 22, pp. 1131-1137, has been retracted by agreement between the journal Editor in Chief, L Heitz-Mayfield, and John Wiley & Sons Ltd. The retraction has been agreed due to image discrepancies, resulting in unreliable data. Images in Figures 2, 3, 4, 7, 8 and 11 have been used in publications representing different time points and experimental conditions. Reference 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 Beagle dogs. Clin Oral Impl Res. 2011;22: 1131-1137. https://doi.org/10.1111/j.1600-0501.2010.02084.x.

Narrow- versus mini-implants at crestal and subcrestal bone levels. Experimental study in beagle dogs at three months.

The objective of this study was to evaluate the osseointegration and crestal bone loss (CBL) in two implant designs with different diameters (Mini Sky® and Narrow Sky®) implants, placed at different vertical levels at healed canine ridges. The second, third, and fourth mandibular premolars of six Beagle dogs were extracted bilaterally. After 2 months healing, four implants divided into two groups according to their diameters (i.e., Narrow Sky® and Mini Sky®) were placed in each hemi-mandible at the level of the bone crest or 2 mm subcrestally. The animals were euthanized at 12 weeks and undecalcified samples were processed for histology. Histomorphometric analysis was carried out to compare bone-to-implant contacts (BIC) and crestal bone loss (CBL). There were not significant differences in CBL between groups when the implants were placed at subcrestal bone level (p > 0.05), meanwhile the CBL was significantly higher for both groups when the implants were inserted at crestal level (p < 0.05). All implants were osseointegrated presenting a minimum BIC percentage of 56%. The major percentages of BIC were found for both groups at subcrestal level (p < 0.05). Within the limitations of this experimental study may be concluded that the implant diameter does not affect the CBL. BIC values are affected by implant diameter and design been higher for narrow implants compared to mini-implants. Subcrestal insertion of both implants favors crestal bone preservation but crestal insertion of both designs is associated with crestal bone loss The study shows that narrow implants protect peri-implant crestal bone.

Surface Morphology of Superficial Cells in Irradiated Oral Mucosa: An Experimental Study in Beagle Dog

Objectives: The aim of the present study is to investigate if radiation induces changes in the superficial cells of the oral mucosa and secondly to describe morphological characteristics of the cell surface structure by scanning electron microscopy (SEM).Materials and methods: Ten beagle dogs aged 1–2 years were used in this study. One side of each mandible was irradiated in two sessions, each lasting 1 week. The total dosage was 40 Gy (Group A; 5 dogs) and 50 Gy (Group B; 5 dogs), in five fractions of 4 Gy. The other side of mandible (non-irradiated) served as a control. The specimen was harvested with a scalpel from the alveolar mucosa of the irradiated area 1 year after irradiation and studied with SEM.Results: In the control side, the surface structure of the cell contains straight parallel or branched microplicae (MPL), which were equally spaced over the cell surfaces. Discontinuous and short MPL were typical cell structure of irradiated mucosa. In 50 Gy group, the surface structure of epithelial cell was pitted and the cell boundaries were thick.Conclusions: The novelty of the present study is that radiation disrupts superficial cells of the oral mucosa. The role of the MPL structure of the superficial cells in mucositis development is discussed.

Effect of orthodontic force on expression of Asporin after tooth auto-transplantation: an experimental study in Beagle dogs

To evaluate the effect of orthodontic light force on the expression of Asporin, bone morphogenetic proteins-2 (BMP-2) and alkaline phosphatase (ALP) after auto-transplantation. Thirty-two maxillary and mandibular incisors in four 13 month-old male Beagle dogs were auto-transplanted to the other side of the same jaw. The teeth were all endodontically treated and divided into four groups, control (group 1) and three experimental groups (groups 2, 3 and 4).In control group, the teeth were unloaded. In the other three experimental groups, continuous force was applied in the 1st week (group 2), 2nd week (group 3) and 4th week (group 4) after auto-transplantation, respectively. The dogs were sacrificed in the 8th week. The mRNA expressions of Asporin,BMP-2 and ALP were examined by real time PCR. The expression of periodontal ligament associated protein-1 (PLAP-1) was examined by Western blotting. The data were statistically analyzed using SPSS 17.0 and one-way analysis of variance (ANOVA). In group 3, the expression of Asporin mRNA (2.047 ± 0.281) was higher than that in the other three groups, while the expression of BMP-2 (1.358 ± 0.095) was lower than that in group 2 and control group (P < 0.05). The expression of PLAP-1 (1.054 ± 0.113) in group 3 was higher than other groups, while significant difference was found between any two groups. Orthodontic force could stimulate the expression of Asporin and PLAP-1. The orthodontic force applied in the 2nd week after the tooth auto-transplantation, the expression of Asporin and PLAP-1 reached the highest level.

Biomechanical Testing of Microblasted, Acid-Etched/Microblasted, Anodized, and Discrete Crystalline Deposition Surfaces: An Experimental Study in Beagle Dogs

Modifications in implant surface topography and chemistry may alter the early bone response at different levels. This study characterized four implant surfaces and evaluated the biomechanical fixation and histologic response at early implantation times in a canine radius model. External-hexagon Branemark-type implants were used with four experimental surfaces: microblasted (MI), acid-etched and microblasted (AAM), anodized (A), and discrete crystalline deposition (DCD). Surface topography was assessed by scanning electron microscopy, interferometry, and x-ray photoelectron spectroscopy. The implants were placed in the central region of the radii of eight beagle dogs and remained in vivo for 10 or 30 days. The implants were torqued to interface failure, and a general linear statistical model with torque as the dependent variable and implant surface and time in vivo as independent variables was used. All surfaces presented were textured, and different surface chemistries were observed. No significant differences between implant surfaces were observed for torque at 10 days. However, at 30 days, the AAM surface presented significantly higher torque values compared to the DCD and A surfaces. Significantly higher torque values were observed at 30 days compared to 10 days (P < .001). Significantly different biomechanical fixation dependent on surface preparation was observed after 30 days, and all surfaces were biocompatible and osteoconductive.

Retracted:Bone remodelling after regenerative procedures around implants placed in fresh extraction sockets: an experimental study in Beagle dogs

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. 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. 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. 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.

Rate of orthodontic tooth movement after changing the force magnitude: an experimental study in beagle dogs

To study a possible dose-response relation between force magnitude and rate of orthodontic tooth movement by altering forces during bodily orthodontic tooth movement. Eight young adult beagle dogs were used. The experiments were carried out in the Central Animal Facility, and all analyses were conducted in the Department of Orthodontics and Oral Biology, Radboud University Nijmegen Medical Centre. Orthodontic appliances were placed exerting a reciprocal force on the mandibular second premolars and first molars. A force of 10 or 300 cN was randomly assigned to each side of the dogs. After 22 weeks, all forces were changed to 600 cN. Based on intra-oral measurements, tooth movement rates were calculated. The premolars showed no difference in the rates of tooth movement with 10 or 300 cN. Replacing 10 for 600 cN increased the rate, but replacing 300 for 600 cN did not. Molars moved faster with 300 than with 10 cN, and changing both forces to 600 cN increased the rate of tooth movement. Data from all teeth were pooled considering their relative root surfaces, and a logarithmic relation was found between force and rate of tooth movement. Only in the very low force range, a positive dose-response relation exists, while in higher force ranges, no such relation could be established.

Effectiveness of two regeneration materials in autogenous tooth transplantation in larger sockets:an experimental study in beagle dogs

Objective To evaluate the effectiveness of regenerous tissue and bone substitute in autogenous tooth transplantation in the larger recipient socket. Methods In 3 Beagle dogs, 18 incisors were transplanted to the recipient sockets, 2 mm wider mesio-distally. The regenerous tissue group, the bone substitute group and the control group contained 7, 7 and 4 teeth respectively. No additional material was used in control group. Clinical and radiographic examinations were done every month and were sacrificed 3 months later. Subsequently, decalcified sections were prepared for routine histological evaluation. Ordinal scores for root surface resorption were analyzed using the Kruskal-Wallis test. Results All donor teeth survived. A statistically significant difference was found among all three treatment groups ( P = 0.0001). The proliferating tissue in space positively affected the periodontal healing without any resorption. Inflammatory resorption of the root surface and formation of new bone were observed in the bone substitute group. Surface resorptions of the roots were found in the control group. Conclusion Proliferating tissues enhance the regeneration of periodontal tissues in larger recipient sockets and prevent root resorption. Sinbone HT is beneficial for the stabilization of the transplanted teeth in larger sockets.

Histomorphometric evaluation of guided bone regeneration around implants with SLA surface: an experimental study in beagle dogs

The aim of this study was to evaluate the efficacy of collagen membranes, either alone or combined with a human demineralized freeze-dried bone allograft (DFDBA) or natural bovine bone graft, in bone defects around dental implants with an SLA (sand-blasted, large grit, acid-etched) surface. The experiments were carried out in three beagle dogs using a split-mouth design. On one side of the jaw, three implants were placed and intra-bony defects were created and covered with a collagen membrane, randomly combined in two of the defects with human DFDBA or inorganic bovine bone graft. A control implant, without membrane covering or defect filling, was also placed. On the other side of the jaw, three implants were placed and the bone defects were treated in a similar fashion, but without membrane covering. The studied variables were the percentage of bone-to-implant contact within the limits of the initial bony defect and percentage of the original bony defect occupied by bone tissue. Although no statistically significant differences were found in this study between the membrane and nonmembrane groups, bone defects augmented with anorganic bovine bone and membranes showed the most promising results from a histological and histomorphometric perspective.

The effect of retention on orthodontic relapse after the use of small continuous or discontinuous forces. An experimental study in beagle dogs.

Relapse is a major concern in orthodontics for which avoidance retention is the general procedure. However, the effect of retention on relapse after active tooth movement with different force regimes has never been studied in a standardized experimental setting. Mandibular third premolars were extracted in 19 young adult beagle dogs. Three months later, the second premolars were bodily moved distally with forces of 10 cN or 25 cN. The forces were applied for 24 h d-1 or for 16 h d-1. After 4 months, relapse was allowed in half of the animals, while in the others relapse was preceded by retention for 90 d. Statistical analyses were performed on the relation between force regime, active tooth movement, retention, and relapse. Force magnitude had no effect on relapse, while continuous forces resulted in a longer-lasting and more pronounced relapse than did discontinuous forces. A significant positive correlation was found between the amount of active tooth movement and both the rate and the total amount of relapse, but not between the amount of active tooth movement and the duration of the relapse. Retention had no effect on the duration of the relapse, but it strongly decreased its total amount. Finally, the effect of retention on the amount of relapse was strongly correlated with the amount of active tooth movement.

Point of View: Intervertebral Disc Reconstitution After Chemonocleolysis With Chymopapain is Dependent on Dosage: An Experimental Study in Beagle Dogs

Point of View: Intervertebral Disc Reconstitution After Chemonocleolysis With Chymopapain is Dependent on Dosage: An Experimental Study in Beagle Dogs