Gökhan Açikgöz

Healing of periodontal defects treated with enamel matrix proteins and root surface conditioning: an experimental study in dogs

Application of enamel matrix proteins has been introduced as an alternative method for periodontal regenerative therapy. It is claimed that this approach provides periodontal regeneration by a biological approach, i.e. creating a matrix on the root surfaces that promotes cementum, periodontal ligament (PDL) and alveolar bone regeneration, thus mimicking the events occurring during tooth development. Although there have been numerous in vitro and in vivo studies demonstrating periodontal regeneration, acellular cementum formation and clinical outcomes via enamel matrix proteins usage, their effects on the healing pattern of soft and hard periodontal tissues are not well-established and compared with root conditioning alone. In the present study, the effects of Emdogain (Biora, Malmö, Sweden), an enamel matrix derivative mainly composed of enamel matrix proteins (test), on periodontal wound healing were evaluated and compared with root surface conditioning (performed with 36% orthophosphoric acid) alone (control) histopathologically and histomorphometrically by means of the soft and hard tissue profile of periodontium. An experimental periodontitis model performed at premolar teeth of four dogs were used in the study and the healing pattern of periodontal tissues was evaluated at days 7, 14, 21, 28 (one dog at each day), respectively. At day 7, soft tissue attachment evaluated by means of connective tissue and/or epithelial attachment to the root surfaces revealed higher connective tissue attachment rate in the test group and the amount of new connective tissue proliferation in the test group was significantly greater than the control group (p<0.01). New bone formation by osteoconduction initiated at day 14 in the test and control group. At day 21, the orientation of supra-alveolar and PDL fibers established, and new cementum formation observed in both groups. At day 28, although regenerated cementum was cellular in all of the roots in the control samples, an acellular type of cementum (1.32+/-0.83 mm in length and 3.16+/-0.23 microm in width) was also noted in six roots of test samples with an inconsistent distribution on the root surfaces. The amount of new cementum was significantly higher in the test group than the control group samples (p<0.01). The width of the cellular cementum in the control group was more than the cellular cementum in the test group, but the difference was not statistically significant (p>0.05). A firm attachment of acellular cementum to the root dentin with functional organization of its collagen fibers was noted, and, the accumulation and organization of cellular cementum in the control group was more irregular than the cellular cementum formed in the test group. The amount of new bone was 2.41+/-0.75 mm in the test and 1.09+/-0.46 mm in the control group at day 28. The rate of bone maturation (the number of osteons) was found higher in the test group (10.75+/-0.85) than the control group (5.50+/-0.86). Under the limitations of the study, our results reveal that when compared with root surface conditioning, enamel matrix proteins have more capacity for stimulating periodontal regeneration via their positive effects on root surfaces, i.e. inhibition of gingival epithelium down growth and stimulation of connective tissue proliferation and attachment to the root surfaces during wound healing. An acellular type of cementum regeneration and new alveolar bone formation by an accelerated osteoconductive mechanism are also achieved with application of enamel matrix proteins.

Long-term evaluation of sandblasted and acid-etched implants used as orthodontic anchors in dogs

The aim of this study was the clinical, radiographic, and histologic evaluation of the tissue surrounding SLA (sandblasted and acid-etched) implants loaded with a continuous and constant force for 52 weeks, after a healing period of 6 weeks, after implant insertion. SLA implants were placed in the maxilla of 3 dogs and the mandible of 5 dogs after a 12-week healing period after extraction. Abutments were attached to the 6 test implants (2 in the maxilla, 4 in the mandible). Superelastic nickel-titanium coil springs were activated between the SLA implants and the canines, producing a force of 200 g (2 N). Two unloaded implants (1 in the maxilla, 1 in the mandible) served as controls. Histologic analysis showed a corticalization of bone trabeculae, thicker at the loaded than at the unloaded implants. New bone formation at the level of the crest was slightly superior in the test implants. A difference between the tension and compression areas could not be observed in the test implants. The mean bone-implant contact values of the test implants for the maxilla and mandible were 40.23% and 49.33%, respectively. In the control implants, the bone-implant contact value was 67.91% for the maxilla and 49.23% for the mandible. SLA implants can be used as an anchorage unit with confidence, in spite of a short healing period and a prolonged force application. Further studies with different force magnitudes and healing periods are required to clarify the effects of healing period and force magnitude on bone quality and quantity.

Comparison of platelet pellet and bioactive glass in periodontal regenerative therapy

Objective. In recent years, platelet-rich plasma combined with graft materials has been used for periodontal regeneration. The individual role of blood products with guided tissue regeneration in periodontal regenerative therapy is unclear and needs to be elucidated. The purpose of this study was to compare the clinical and radiological effectiveness of platelet pellet/guided tissue regeneration (PP/GTR) and bioactive glass/GTR (BG/GTR) treatments in patients with periodontal disease. Material and methods. Using a split mouth design, 15 chronic periodontitis patients with pocket depths ≥ 6 mm following periodontal initial therapy were randomly assigned to treatment with a combination of PP/GTR or BG/GTR in contralateral dentition areas. An absorbable membrane of polylactic acid was used GTR. The criteria for the comparative study were preoperative and postoperative 6 months pocket depth, clinical attachment level, and radiological alveolar bone level. Results. Both treatment modalities resulted in significant pocket depth reduction and gain in clinical attachment and alveolar bone level compared to the preoperative values (p<0.01). Reduction in pocket depth, gain in clinical attachment and alveolar bone level were 4(3–6), 4.1±0.7, 4.9±1.4 mm in the PP/GTR group and 4(3–7), 4.1±1.2, 5.9±1.7 mm in the BG/GTR group, respectively. The differences between the two groups were not statistically significant (p>0.05). Conclusions. Within the limits of this study, it was concluded that PP may be effective as a bioactive glass graft material and used as a graft material for treating intrabony defects. PP thus appears to be a suitable alternative in the regenerative treatment of intrabony periodontal defects.

Gingival levels of monocyte chemoattractant protein-1 (MCP-1) in diabetes mellitus and periodontitis: an experimental study in rats

The objectives of this study were to investigate and compare the monocyte chemoattractant protein-1 (MCP-1) levels of gingival tissues in diabetes mellitus (DM) and periodontitis and to reveal the effects of MCP-1 on periodontal inflammation and destruction in these diseases. DM was created in 15 rats (group 1) by streptozotocin injection, and periodontitis was obtained by ligature induction in 15 rats (group 2). Fifteen systemically and periodontally healthy rats were used as control (group 3). Gingival MCP-1 levels were measured by enzyme-linked immunosorbent assay (ELISA). Periodontal inflammation was quantified by the inflammatory cell infiltration in the gingival samples, whereas periodontal destruction was assessed by the alveolar bone loss in the experimental regions. MCP-1 concentrations were higher in groups 1 and 2 than in group 3 (p < 0.001). Increased gingival inflammatory cell infiltration and alveolar bone loss were observed in groups 1 and 2 compared to group 3 (p < 0.001). There were positive correlations among the MCP-1 level, gingival inflammatory cell infiltration, and alveolar bone loss in groups 1 and 2 (p < 0.001). Our results suggest that (1) DM may lead to enhanced MCP-1 production in periodontal tissues likewise for periodontitis and (2) there may be a positive correlation between the MCP-1 concentration and diseased nature of periodontium in both diseases.

The Relationship between Proliferating Cell Nuclear Antigen Expression and Histomorphometrical Alterations in Cyclosporin A-Induced Gingival Overgrowth in Rats

The aim of this study was to investigate the relationship between Proliferating Cell Nuclear Antigen (PCNA) expression and histomorphometrical alterations in cyclosporin A (CsA)-induced gingival overgrowth with or without microbial dental plaque accumulation. Forty male Wistar rats were equally divided into 4 groups; Group I (control); Group II (CsA); Group III (ligature); Group IV (ligature and CsA). After 8 weeks of experimental period, rats were subsequently decapitated and mandibular molars were dissected. Gingival overgrowth was determined by measuring depth of the gingival sulcus, then the mandible were decalcified and serial sections were obtained for histomorphometric and immunohistochemical analysis. Histomorphometric analysis included the measurement of epithelial thickness; immunohistochemical analysis included the assessment of PCNA expression in the oral and sulcular epithelium of buccal and lingual gingiva. Epithelial thickness and PCNA expression were significantly increased in buccal oral epithelium of Group II (p < 0.05) and in all regions in Group IV (p < 0.05) compared to control group. Also gingival overgrowth was more prominent in Group IV in comparison to Group II. These results indicate that CsA-induced gingival alterations are closely accociated with increased epithelial proliferative activity, and dental plaque accumulation seems not to be an essential but to be an aggrevating factor for the progression of the lesion.

ORAL AND DENTAL FINDINGS IN FANCONI'S ANEMIA

Fanconis anemia is an autosomal recessive disorder characterized by progressive pancytopenia and congenital malformation of the skeleton. This study investigated the oral health status of 15 children with Fanconis anemia, including oral lesions, gingival and periodontal status, and dental abnormalities. All children in the group were found to have a tendency to develop tooth decay and were in need of dental treatment. Two had aggressive periodontitis. In one patient supernumerary teeth were found, while in another teeth were congenitally missing. The increased tendency toward periodontal disease in patients with Fanconis anemia may be due not only to the anemia, leukopenia, and defective detoxification of oxygen radicals that are characteristic of the disease itself, but also to medications applied during intense immunosuppressive treatment, such as prednisolone.

Correlation of Hepatitis C Antibody Levels in Gingival Crevicular Fluid and Saliva of Hepatitis C Seropositive Hemodialysis Patients

Search for hepatitis C virus (HCV) in body fluids other than blood is important when assessing possible nonparenteral routes of viral transmission. However, the role of oral fluids in HCV transmission remains controversial. Our aim was to compare the prevalence of HCV antibody (HCV Ab) levels in saliva, and gingival crevicular fluid (GCF) of HCV seropositive hemodialysis patients. Serum, saliva and GCF samples were collected from thirty-nine patients. Samples were analyzed for HCV Ab using the Ortho HCV 3.0 SAVe enzyme-linked immunosorbent assay (ELISA). HCH Ab levels in saliva and GCF of all HCV-seropositive patients were statistically compared. Reported here are the results of the study designed to determine the correlation between HCV-RNA positivity in serum and the detection of antibodies in GCF and saliva. One hundred percent (100%) of the 39 patients have antibodies to HCV in their serum, 15.4% have antibodies to HCV in GCF, and saliva found out. HCV Ab seropositivity in GCF and saliva was significantly correlated (kappa = 0.462; P < .001). This study supports the concept that GCF may be a significant source of HCV in saliva.

The Effect of Cyclosporin A on Alveolar Bone in Rats Subjected to Experimental Periodontal Disease

Cyclosporine A (CsA), broadly used in organ transplantation, may contribute to pathogenesis of osteoporosis. The aim of this study was to investigate the effects of CsA on alveolar bone in rats subjected or not to experimental periodontal disease using biochemical, radiographic, and histometric analysis. Forty Wistar rats were divided into 4 equal groups: Group I (Control), Group II (CsA was injected subcutaneously in a daily dose of 10 mg/kg), Group III (Ligature was placed around the mandibular molars), Group IV (Ligature+CsA). After 60 days, rats were decapitated, serum alkaline phosphatase and calcium levels were measured. Radiographic-alveolar bone loss (ABL), histometric-ABL, and percentage of new alveolar bone formation (NABF%) were determined on mandibular molars. Significant increase in serum alkaline phosphatase levels (p < 0.001), no significant difference in calcium levels were observed (p > 0.05) in Group IV compared to Group III. Radiographic and histometric-ABL were significantly less (p < 0.001), NABF% was significantly greater (p < 0.05) in Group IV than in Group III. No significant difference in any of the parameters between Group II and Group I was found. It can be concluded that in the presence of periodontal disease, CsA treatment may bring out an imbalance in the alveolar bone homeostasis by decreasing resorption and stimulating formation of alveolar bone in rats.

Platelet-rich plasma and autogenous bone graft combined with guided tissue regeneration in periodontal fenestration defects in dogs.

The aim of this study was to evaluate the effects of platelet-rich plasma (PRP), autogenous bone (AB), and guided tissue regeneration (GTR) combination therapy compared to GTR therapy alone on healing of bone and cementum in fenestration-type periodontal defects in dogs. Six dogs were included in this study. Fenestration-type defects were created, and the following treatment groups were established: a control group treated with GTR alone and experimental groups treated with a combination of GTR + PRP, GTR + AB, and GTR + AB + PRP. The defects were evaluated by stereologic method and histomorphometric analysis, which were performed 4, 8, and 12 weeks postoperatively. The results showed a significant increase in trabecular bone area in the GTR + PRP group as compared with the control at 4 and 8 weeks (P < .05). The GTR + AB + PRP group showed significantly more trabecular bone area than both GTR and GTR + PRP groups at all time intervals (P < .05). The 8- and 12-week results in terms of cementum area revealed a significant difference between the GTR + AB + PRP group and the control in favor of the former (P < .05). Cementum area in the GTR + AB group was significantly greater than that in the GTR group at all time intervals (P < .05). Within the limitations of this study, PRP and AB, when used under barrier membrane, resulted in significant improvement in bone and cementum formation compared to GTR alone in periodontal fenestration defects; AB, rather than PRP, was responsible for this outcome.

Effect of defective collagen synthesis on epithelial implant interface: lathyritic model in dogs. An experimental preliminary study.

Peri-implant mucosa is composed of 2 compartments: a marginal junctional epithelium and a zone of connective tissue attachment. Both structures consist mainly of collagen. Lathyrism is characterized by defective collagen synthesis due to inhibition of lysyl oxidase, an enzyme that is essential for interfibrillar collagen cross-linking. The lathyritic agent beta-aminoproprionitrile (β-APN) is considered a suitable agent to disrupt the connective tissue metabolism. Therefore, the purpose of this study was to assess the effect of defective connective tissue metabolism on epithelial implant interface by using β-APN created chronic lathyrism in the canine model. Two 1-year-old male dogs were included in this study. A β-APN dosage of 5 mg/0.4 mL/volume 100 g/body weight was given to the test dog for 10 months, until lathyritic symptoms developed. After this, the mandibular premolar teeth (p2, p3, p4) of both dogs were atraumatically extracted, and the investigators waited 3 months before implants were placed. In the test dog, 3 implants were placed in the left mandible, and 2 implants were placed in the right mandible. In the control dog, 2 implants were placed in the left mandibular premolar site. The dogs were sacrificed 10 months after healing. Peri-implant tissues obtained from the dogs were examined histomorphologically and histopathologically. Bone to implant contact (BIC) values and bone volumes (BV) were lower in the lathyritic group compared to the control group; however, no statistical significance was found. Significant histologic and histomorphometric changes were observed in peri-implant bone, connective tissue, and peri-implant mucosal width between test and control implants. Defective collagen metabolism such as lathyrism may negatively influence the interface between implant and surrounding soft tissue attachment.