Bacterial adhesion and colonization differences between zirconium oxide and titanium alloys: an in vivo human study.

PURPOSE: The purpose of this study was to compare zirconium oxide and titanium alloys with respect to their tendency to adhesion and colonization of two periodontal pathogens on both hard surfaces and on soft tissues in vivo. MATERIALS AND METHODS: The present study was designed as a prospective stratified randomized controlled clinical trial. Patients were scheduled to receive two implants with different types of abutments in the posterior mandible. Three months after implant placement, titanium and zirconium abutments were connected. Five weeks after abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsy samples were obtained. Abutments and biopsy specimens were analyzed by reverse-transcriptase polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated by sesile water drop before replacement. RESULTS: No statistically significant differences were found between probing depths or DNA copy numbers of A actinomycetemcomitans, P gingivalis, and total bacteria both for both titanium alloys and zirconium oxide surfaces and the biops specimens obtained from their buccal gingival. With respect to the surface free energy of zirconium and titanium abutments, zirconium abutments showed lower surface free energy than titanium abutments. CONCLUSION: The results of this study showed that zirconium oxide surfaces have comparable properties to titanium alloy surfaces in their tendency to adhesion and colonization of two periodontal pathogens on both hard surfaces and in soft tissues.

Encapsulation and osteoinduction of human periodontal ligament fibroblasts in chitosan-hydroxyapatite microspheres.

Periodontal ligament cells play a crucial role in the regeneration of periodontal tissues and an undifferentiated mesenchymal cell subset is thought to exist within this population. The aim of this study was to assess the osteogenic differentiation potential of human periodontal ligament fibroblasts (hPDLFs) in three dimensional (3D)-osteogenic culture environment following encapsulation in chitosan-hydroxyapatite (C/HA) microspheres with the size range of 350-450 microm. Human PDLF cultures were established and three experimental groups were formed: (i) two-dimensional (2D)-culture as single cell monolayer, (ii) 3D-static culture of C/HA encapsulated hPDLFs, and (iii) 3D-dynamic culture of C/HA encapsulated hPDLFs in a rotating wall vessel bioreactor. The cells were cultured in standard culture medium supplemented with beta-glycerophosphate, dexamethasone, and ascorbic acid. After 21 days, immunohistochemistry was performed using antibodies against osteonectin, osteopontin, bone-sialoprotein, and osteocalcin as osteogenic differentiation markers. Phase-contrast and scanning electron microscopy observations were used for histological and morphological evaluation. The combined effects of osteoinductive medium and HA-containing composite microsphere material on encapsulated hPDLFs resulted in the transformation of a considerable portion of the cells into osteoblastic lineage at the end of the experiments. Results demonstrate the ability of hPDLFs to undergo osteogenic differentiation upon induction in vitro, both under 2D and 3D culture conditions. C/HA microspheres in microgravity bioreactor may serve as a suitable 3D environment to support the osteogenic differentiation of human PDLFs, in vitro.

Comparison of different methods to detect Helicobacter pylori in the dental plaque of dyspeptic patients.

The aim of this study was to compare different methods of detection of Helicobacter pylori (H. pylori) in the dental plaque of dyspeptic patients. After recording the clinical indices, culture and polymerase chain reaction (PCR) methods were performed on plaque samples, while rapid urease test in addition to these tests was carried on gastric samples from 67 dyspeptic patients who attended for an upper gastrointestinal endoscopy. Forty-seven of 67 patients were H. pylori-positive in gastric biopsy material whereas the microbial dental plaque from 19 patients demonstrated H. pylori positivity detected by PCR. Among the patients, 25.4% harbored H. pylori both in the stomach and in microbial dental plaque. No significant correlations were found among the presence of H. pylori in the stomach, in plaque, and clinical variables (P > 0.05). Although oral hygiene was observed optimal and the mean of pocket depth was not found to be higher, the prevalence of H. pylori was observed to be higher in dental plaque. According to our results, PCR technique gave the highest detection rate both in gastric biopsy and in dental plaque compared to the other methods used.

Gingival crevicular fluid alkaline phosphatase levels in postmenopausal women: effects of phase I periodontal treatment.

BACKGROUND: The aim of this study was to determine how estrogen status may possibly influence gingival crevicular fluid (GCF) alkaline phosphatase (ALP) levels in estrogen-deficient (ED) and -sufficient (ES) postmenopausal women at baseline (BL) and 1 year after periodontal phase I treatment (AT). METHODS: Thirty-six postmenopausal women on estrogen supplements (mean serum estradiol levels >30 pg/ml; estrogen sufficient) and 37 postmenopausal women not on estrogen supplements (mean serum estradiol levels <30 pg/ml; ED) were divided into two subgroups as chronic periodontitis and clinically healthy controls after clinical and radiographic examination. The ES group consisted of 19 control (ES/C) and 17 chronic periodontitis (ES/P) patients, and the ED group consisted of 20 control (ED/C) and 17 chronic periodontitis (ED/P) patients. Plaque (PI) and gingival (GI) indices, bleeding on probing (BOP), probing depths (PD), clinical attachment loss (CAL) scores, and GCF samples were recorded at BL and AT. The levels of ALP in the GCF were measured photometrically. The paired samples Student t and Wilcoxon tests were used to compare the ALP levels and clinical parameters between BL and AT. The correlation among the ALP and clinical parameters was analyzed using the Pearson correlation. RESULTS: The mean of all clinical parameters (PI, GI, BOP, PD, and CAL) was significantly (P <0.05) higher in periodontitis groups (ES/P and ED/P) than controls (ES/C and ED/C). Periodontitis groups (ES/P and ED/P) demonstrated significantly increased GCF volumes and GCF ALP levels (P <0.05) compared to controls (ES/C and ED/C). There were no significant differences in the concentrations of ALP between periodontitis and control groups (P >0.05). The BL GCF ALP total levels of the ED/P group were significantly higher than the ES/P group (P <0.05). The BL and AT serum ALP levels of the ED/P group were not significantly but were numerically higher than the ES/P group. One year after periodontal treatment, the GCF volume, GCF ALP total, and concentrations decreased significantly in both periodontitis groups (P <0.05). However, the GCF ALP levels were still numerically higher in the ED/P group. A positive statistical correlation was found between total ALP levels and PD (r = 0.621; P <0.05). CONCLUSION: These data suggest that the presence of ALP in GCF is not simply a reflection of the local inflammation state and that a patient's estrogen status may possibly influence local ALP levels in GCF.

Periodontal regenerative potential of autogenous periodontal ligament grafts in Class II furcation defects.

BACKGROUND: The aim of the present study was to evaluate the regenerative potential of autogenous periodontal ligament (PDL) grafts in the treatment of Class II furcation defects. METHODS: Twenty mandibular Class II furcation defects from 10 systemically healthy patients with chronic periodontitis were selected. In experimental defects, flaps were coronally positioned following placing autogenous PDL grafts that were obtained from third molars; in controls, coronally advanced flap procedure without graft was applied. Clinical measurements including plaque index, gingival index, probing depth (PD), vertical and horizontal clinical attachment level (CAL), and gingival recession (GR) were obtained at baseline and after 3 and 6 months postoperatively. Vertical and horizontal defect fill was evaluated with open clinical measurements at initial surgery and reentry after 6 months. Gingival biopsies from the experimental and control defects were obtained at reentry and evaluated histopathologically in order to examine the soft tissue response towards PDL grafts. RESULTS: Sites treated with PDL grafts demonstrated significant improvement in vertical and horizontal defect fill, PD, and CAL at 3 and 6 months compared to presurgical values. The difference determined for the PD values of both groups at a statistically significant degree in favor of grafted sites was maintained at all observation periods. No foreign body reaction was observed in PDL grafts. CONCLUSIONS: These short-term results point to the potential of PDL grafts in promoting healing of furcation lesions. This preliminary study suggests that the use of PDL grafts may have beneficial effects in the treatment of furcation defects.

Comparative clinical study of connective tissue graft and two types of bioabsorbable barriers in the treatment of localized gingival recessions.

BACKGROUND: Localized buccal recessions occur in more than 60% of individuals; therefore, there is a need for predictable root coverage techniques. The objective of the present study was to evaluate the clinical effectiveness of the guided tissue regeneration (GTR) procedure versus connective tissue graft (CTG) in the treatment of localized gingival recessions over a 12-month postoperative period. METHODS: Thirty bilateral matched pairs of localized buccal recessions in 22 patients were treated with CTG and GTR in this study. For the GTR procedure, two types of bioabsorbable barriers, polylactide/polyglycolide acid (PLGA) and solvent dehydrated duramater allograft (SDDA) membranes, were used and CTG was obtained from the palatal mucosa. The selected pairs of teeth were randomly assigned to one of three groups (10 pairs per group): group 1, PLGA (10 recessions) or CTG (10 recessions); group 2, SDDA (10 recessions) or CTG (10 recessions); or group 3, PLGA (10 recessions) or SDDA (10 recessions). Statistical analysis evaluated both intra- and intergroup measurements. The height of gingival recession (GR), width of keratinized tissue (KT), clinical attachment level (CAL), and probing depth (PD) were assessed at baseline and at 6, 9, and 12 months following surgery. RESULTS: The amount of root coverage was 74.3%, 69.6%, and 86.3% with PLGA, SDDA, and CTG, respectively. The gain in KT was significant in the CTG group (P<0.05). No significant differences were observed among the three groups with respect to PD and CAL. CONCLUSIONS: Results of this study indicate that all techniques led to an improvement of all clinical parameters except PD from baseline. However, CTG increased KT considerably compared to GTR. The final esthetic results were similar for the two membranes and connective tissue graft.

Evaluation of cellular response to collagen membranes enriched with fibronectin light and transmission electron microscope study.

This study was undertaken to evaluate the biocompatibility, cellular reaction and resorption characteristics of a type I bovine collagen membrane material either enriched with or without fibronectin solution in vivo using light (LM) and transmission electron microscopy (TEM). Experimental osseous dehiscence defects were surgically produced bilaterally on the labial aspect of the mandibular 2nd, 3rd, and 4th premolar teeth in four mongrel dogs. Collagen membranes rehydrated with fibronectin solution (group FM) and membranes rehydrated with saline (group M) were placed over the bony defects. The third premolar teeth on which the flap operation was performed served as control (group C), with no membrane placed. Flaps were positioned slightly coronally and sutured. Gingival tissue samples and block biopsies were obtained from all experimental and control sites for LM and TEM evaluation at 7 days. For each group, morphometric analysis was performed and the numbers of macrophages in the most coronal area of the free gingiva were counted. Postoperative healing was uneventful during the experimental period, and all membranes remained covered. Light microscopic evaluation revealed similar resorption patterns in the most coronal area of the membranes both enriched with and without fibronectin solution within the first 7 days. The mean numbers of macrophages were higher in experimental groups than in the control group. In TEM evaluation, more excessive intracellular macrophage activity was observed in group M than group FM. As a result of these observations it may be concluded that similar resorption characteristics existed in the most coronal area in both experimental groups with LM evaluation, but with TEM it was observed that the membranes enriched with fibronectin solution were resorbed more slowly at the ultrastructural level.