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The aim of the present study was to histologically evaluate extraction wound healing after socket preservation using a beta-TCP root taper.Ten dogs were used in the study. Immediately following careful extraction of the first premolar of the lower jaw the extraction sockets were filled using a chair-side thermically formed polylactide-linked root taper (RT). To avoid contamination, a further polylactide barrier covered the crestal surface of the taper. Untreated extraction sites of the opposite side served as control. After three and six months of healing, the animals were sacrified and dissected blocks were prepared for histomorphometrical analysis. Following parameters were evaluated: difference between lingual and buccal bone height, lingual and buccal alveolar wall and total bone width 1, 3 and 5mm underneath the top of the respective crest. During the entire study period healing was uneventful for all animals. Histological analysis of three months specimens revealed a definable area of minor mineralized bone within the former extraction sockets in both RT and control group. In the test group small areas of material organized by connective tissue but no remnants of the bone substitute material could be observed. After six months the borderline between new and pre-existing bone had disappeared. Histomorphometric analysis revealed no statistically significant differences between test and control group after three or six months (p>0.05, paired T-test). Within the limits of the present study it was concluded that the application of polylactide-stabilized RT does not improve the dimensional ridge alterations after tooth extraction.

The aim of the present study was to investigate bone formation to recombinant human bone morphogenetic protein-2 (rhBMP-2)-biocoated and rhBMP-2-nonbiocoated titanium implants after implantation in dogs. Implantation of sand-blasted and acid-etched (C), chromosulfuric acid surface-enhanced (CSA), and rhBMP-2-biocoated CSA [BMP-A: noncovalently immobilized rhBMP-2 (596 ng/cm(2)), BMP-B: covalently immobilized rhBMP-2 (819 ng/cm(2))] implants was performed in both the mandible and tibia of dogs. After 4 weeks of healing, the percentage of direct bone to implant contact (BIC) and the induced bone density (BD) at a distance of less than and greater than 1 mm adjacent to each implant was assessed. Histomorphometric analysis of implants inserted in the mandible and tibia revealed that BIC values appeared to be highest in the BMP-B group, followed by BMP-A, CSA, and C. BD as measured at a distance of <1 mm revealed obvious differences between groups: BMP-B>BMP-A>CSA>C. However, no differences between groups were observed at a distance of >1 mm. Within the limits of the present study, it may be concluded that rhBMP-2 immobilized by covalent and noncovalent methods on CSA-treated implant surfaces seemed to be stable and promoted direct bone apposition in a concentration-dependent manner.

The aim of the present study was to immunohistochemically evaluate angiogenesis pattern of native and cross-linked collagen membranes after subcutaneous implantation in rats. Five commercially available and three experimental membranes (VN) were included: (1) BioGide (BG), (2) BioMend (BM), (3) BioMend Extend (BME), (4) Ossix (OS), (5) TutoDent (TD), and (6-8) VN(1-3). Specimens were randomly allocated in unconnected subcutaneous pouches (n=4) separated surgically on the back of 40 wistar rats, which were divided into five groups (2, 4, 8, 16, and 24 weeks), including eight animals each. Pattern of angiogenesis was labelled using primary mouse monoclonal antibody to transglutaminase II. For each membrane, the period of time, needed for a complete and homogeneous transmembraneous vascularization, was assessed immunohistomorhometrically. Differences between the membranes were found regarding the initial pattern of transmembraneous angiogenesis, as evaluated 2 weeks following implantation. Mean cross- and longitudinal-sectional area of blood vessels (%) was highest for VN(3) (5.27+/-2.73), followed by BG (2.45+/-0.88), VN(1) (2.07+/-0.29), VN(2) (1.91+/-0.55), TD (1.44+/-0.53), BME (0.35+/-0.29) and BM (0.25+/-0.4). In contrast to BG and VN(1-3), BM, BME and TD exhibited a homogeneous transmembraneous formation of blood vessels merely 4-8 weeks following implantation. OS, however, exhibited no signs of angiogenesis throughout the whole study period. Within the limits of the present study, it may be concluded that pattern of transmembraneous angiogenesis markedly differs among the membranes investigated.

The aim of the present study was to evaluate the influence of plaque biofilm removal on the mitochondrial activity of human SaOs-2 osteoblasts grown on titanium surfaces. Volunteers wore acrylic splints with structured titanium discs for 72 h to build up plaque biofilms (n = 30). Specimens were randomly instrumented using either (1) an ultrasonic system at two power settings (EMS1, EMS2) + chlorhexidine (CHX), or (2) plastic curettes + CHX. Untreated (NC, n = 10) and sterile (C, n = 10) titanium discs served as controls. Specimens were incubated with SaOs-2 cells for 6 days. Treatment time (T), residual plaque biofilm (RPB)/clean implant surface areas (%), mitochondrial cell activity (MA) (counts/second), and cell morphology (SEM) were assessed. Statistical analysis revealed the following mean scores (+/-SD): RPB areas: P (58.5 +/- 4.9) > EMS1 (38.4 +/- 4.1) > EMS2 (28.3 +/- 2.0); T: PC (292 +/- 30) = EMS1 (244 +/- 24) > EMS2 (199 +/- 25); MA: C (1.544.661 +/- 203.442) > PC (597.559 +/- 566.984) = EMS2 (389.875 +/- 409.300) = EMS1 (356.653 +/- 293.863; n.s.) > NC (138.676 +/- 86.666). In NC and PC groups, cells were predominantly rounded in shape. However, in the EMS groups, some cells had started to spread, showing complete cytoplasmatic extensions of the cell body on the titanium surface. A monolayer of flattened cells was generally observed in the C group. Within the limits of the present study, it was concluded that MA seemed to be impaired by the presence of RPB areas. However, its removal alone might not be the crucial step in the reestablishment of the biocompatibility of titanium surfaces.

A material which is used as a barrier for GBR/GTR procedures has to satisfy several physicochemical characteristics such as biocompatibility, tissue integration, barrier function, and dimensional stability. Recently, many investigations reported on the use of products derived from type I and type III porcine or bovine collagen. Collagen membranes are predominantly resorbed by enzymatic activity (protease and collagenase). To decrease resorption, various physical and chemical cross-linking techniques have been used. Although nowadays cross-linking of collagen seems to be a commonly used procedure, its impact on physicochemical properties of the membrane is still unknown. The aim of the present literature review is to evaluate the potential use of different collagen membranes for GBR/GTR procedures.

The aim of the present study was to compare the biodegradation of differently cross-linked collagen membranes in rats. Five commercially available and three experimental membranes (VN) were included: (1) BioGide (BG) (non-cross-linked porcine type I and III collagens), (2) BioMend (BM), (3) BioMendExtend (BME) (glutaraldehyde cross-linked bovine type I collagen), (4) Ossix (OS) (enzymatic-cross-linked bovine type I collagen), (5) TutoDent (TD) (non-cross-linked bovine type I collagen, and (6-8) VN(1-3) (chemical cross-linked porcine type I and III collagens). Specimens were randomly allocated in unconnected subcutaneous pouches separated surgically on the back of 40 wistar rats, which were divided into five groups (2, 4, 8, 16, and 24 weeks), including eight animals each. After 2, 4, 8, 16, and 24 weeks of healing, the rats were sacrificed and explanted specimens were prepared for histologic and histometric analysis. The following parameters were evaluated: biodegradation over time, vascularization, tissue integration, and foreign body reaction. Highest vascularization and tissue integration was noted for BG followed by BM, BME, and VN(1); TD, VN(2), and VN(3) showed prolongated, while OS exhibited no vascularization. Subsequently, biodegradation of BG, BM, BME and VN(1) was faster than TD, VN(2), and VN(3). OS showed only a minute amount of superficial biodegradation 24 weeks following implantation. Biodegradation of TD, BM, BME, VN(2), and VN(3) was associated with the presence of inflammatory cells. Within the limits of the present study, it was concluded that cross-linking of bovine and porcine-derived collagen types I and III was associated with (i) prolonged biodegradation, (ii) decreased tissue integration and vascularization, and (iii) in case of TD, BM, BME, VN(2), and VN(3) foreign body reactions.

The aim of this controlled, parallel design clinical study was to compare the effectiveness of an Er:YAG laser (ERL) to that of mechanical debridement using plastic curettes and antiseptic therapy for nonsurgical treatment of peri-implantitis. Twenty patients with moderate to advanced peri-implantitis lesions were randomly treated with either (1) an ERL using a cone-shaped glass fiber tip at an energy setting of 100 mJ/pulse and 10 pps (ERL), or (2) mechanical debridement using plastic curettes and antiseptic therapy with chlorhexidine digluconate (0.2%) (C). The following clinical parameters were measured at baseline, 3 and 6 months after treatment by one blinded and calibrated examiner: Plaque index (PI), bleeding on probing (BOP), probing depth (PD), gingival recession (GR) and clinical attachment level (CAL). At the baseline examination, there were no statistically significant differences in any of the investigated parameters. Mean value of BOP decreased in the ERL group from 83% at baseline to 31% after 6 months (P < 0.001) and in the C group from 80% at baseline to 58% after 6 months (P < 0.001). The difference between the two groups was statistically significant (P < 0.001, respectively). The sites treated with ERL demonstrated a mean CAL change from 5.8 +/- 1 mm at baseline to 5.1 +/- 1.1 mm (P < 0.01) after 6 months. The C sites demonstrated a mean CAL change from 6.2 +/- 1.5 mm at baseline to 5.6 +/- 1.6 mm (P < 0.001) after 6 months. After 6 months, the difference between the two groups was statistically not significant (P > 0.05). Within the limits of the present study, it was concluded that (i) at 6 months following treatment both therapies led to significant improvements of the investigated clinical parameters, and (ii) ERL resulted in a statistically significant higher reduction of BOP than C.

The purpose of the present study was to investigate the effects of an enamel matrix protein derivative (EMD) on attachment, proliferation, and viability of human SaOs(2) osteoblasts on titanium implants. A total of 220 sand-blasted and acid-etched (SLA) titanium discs were placed into 24-well culture plates. Before cell inoculation, McCoy's 5A medium (MCM) containing EMD at 25 micro g/ml, 50 micro g/ml, 100 micro g/ml, and 200 micro g/ml was added, and the culture plates were incubated for 30 min. As control, MCM alone was used. Human osteoblast-like cells (SaOs(2)) (2 x 10(4) cells, fourth passage) were suspended in MCM containing 1% penicillin/streptomycin and 10% fetal bovine serum and then inoculated into the well chambers. The medium was changed after 3 days without the addition of EMD. At days 1, 3, and 6, DNA content of the cells was assessed using the CyQuant cell proliferation assay kit, and mitochondrial activity of the cells was measured using a CellTiter-Glo luminescent cell viability assay. The presence of EMD on the titanium discs at days 1 and 6 was evaluated using immunofluorescence stain (IFS) by means of polyclonal antibodies against amelogenin. Additionally, cell morphology was investigated using scanning electron microscopy. Enamel matrix derivative at 25 micro g/ml, 50 micro g/ml, 100 micro g/ml, and 200 micro g/ml demonstrated similar increases in cell proliferation as the control medium at days 3 and 6 ( P>0.05 between groups, respectively). Proliferation, however, appeared to be ameliorated with increasing EMD concentrations. At 25 micro g/ml and 50 micro g/ml, EMD also demonstrated an increase in cell viability similar to the control medium at days 3 and 6 ( P>0.05 between groups, respectively), while EMD at 100 micro g/ml and 200 micro g/ml resulted in statistically significant higher increase in cell viability than in the control medium at day 6 ( P<0.001 between groups, respectively). In all test groups, IFS at day 6 was markedly lower than at day 1. Scanning electron microscopy revealed comparable cell morphology in all groups. Within the limits of the present study, it was concluded that EMD enhanced cell proliferation and viability of human SaOs(2) osteoblasts on SLA titanium implants in a concentration-dependent manner.

The aim of the present study was to evaluate the biocompatibility of differently cross-linked collagen membranes in cultures of human PDL fibroblasts and human osteoblast-like cells. Four collagen membranes [BioGide (BG), BioMend (BM), Ossix (OS) and TutoDent (TD)] were tested. Cells plated on culture dishes (CD) served as positive controls. Six specimens of each membrane were incubated with (1) human PDL fibroblasts [2 x 10(4) cells] (n=24), and (2) human osteoblast-like cells (SaOs-2) [2 x 10(4) cells] (n=24) under standardized conditions. After 7 days, adherent cells were stained with hematoxylin and counted using a reflected light microscope and the cell density per square millimeter was calculated. Additionally, cell morphology was investigated using scanning electron microscopy (SEM). Cell counts were presented as means and standard deviations (cells/mm(2)) and analyzed for statistical difference using the Wilcoxon test: (1) CD (434+/-76)>BG (64+/-19)=OS (61+/-8)>TD (44+/-4)>BM (12+/-5); (2) CD (453+/-92)>BG (94+/-46)=TD (84+/-49)>OS (41+/-23)>BM (0). SEM examination revealed that PDL fibroblasts adherent on BG, TD and OS appeared spindle-shaped and flat, like cells on CD. SaOs-2 osteoblasts adherent on CD were star shaped and flat, but mostly round in shape on BG, OS and TD. BM appeared to be incompatible with the attachment and proliferation of SaOs-2 cells; however, a few PDL fibroblasts were found in a round shape. Within the limits of the present study, it was concluded that (i) BG, TD and OS promoted, and (ii) BM inhibited the attachment and proliferation of human PDL fibroblasts and human SaOs-2 osteoblasts.

The aim of the present study was to investigate the collateral damage of an Er:YAG laser on bone cells in vitro using a special application tip designed for treatment of periimplantitis. Before laser irradiation, SaOs-2 osteoblasts (2 x 10(4) cells) were inoculated into 96-well tissue culture plates and incubated for 48 h under standardised conditions. A total of 120 cell cultures were irradiated with an Er:YAG laser using a cone-shaped quartz glass fibre tip at energy settings of 40, 60, 80 and 100 mJ at 10 Hz (energy densities of 5.08, 7.62, 10.16 and 12.7 J cm(-2)) for 10 s. Each energy setting was used at a distance of 1, 2 and 3 mm between the application tip and the bottom of the culture plate. Following irradiation, mitochondrial activity of the cells was measured using a luminescent cell viability assay. After laser irradiation, mitochondrial activity of SaOs-2 osteoblasts was significantly reduced when compared with nonirradiated cells (P < 0.001), dependent on the energy setting used and the distance between the application tip and the bottom of the culture plate. Mitochondrial activity increased significantly with decreasing energy settings and increasing distances (P < 0.001). Within the limits of the present study, it was concluded that an Er:YAG laser, used with a cone-shaped glass fibre tip designed for treatment of periimplantitis, has detrimental effects on mitochondrial activity of SaOs-2 osteoblasts in vitro at energy settings of 40, 60, 80 and 100 mJ (10 Hz).

The aim of the present study was to investigate the effects of an Er:YAG laser (ERL) and the Vector ultrasonic system (VS) on the biocompatibility of titanium implants in cultures of human osteoblast-like cells (SAOS-2). One hundred and sixty-eight titanium discs with four different surfaces (sand-blasted and acid-etched, titanium plasma-sprayed, machine-polished, and hydroxyapatite-coated) were used to evaluate cell attachment. The samples were equally and randomly assigned to the following groups: (1) an ERL at an energy level of 100 mJ/pulse and 10 Hz using a special application tip, (2) the VS using carbon fibre tips, or (3) untreated control (C). The discs were placed in culture plates, covered with a solution of SAOS-2 cells, and incubated for 7 days. The specimens were then washed with phosphate buffer to remove cells not attached to the surface, and the adherent cells were stained with hematoxilin-eosin. Cells were counted using a reflected light microscope and the cell density per mm2 was calculated. Additionally, cell morphology and surface alterations of the titanium discs after treatment were investigated using scanning electron microscopy (SEM). All titanium discs treated with ERL demonstrated nearly the same cell density per mm2 as the untreated C surfaces. There was a significant decrease in the number of cells that attached to the implant surfaces treated with VS. The SEM examination showed no visible differences between lased and C titanium surfaces. All surfaces treated with VS showed conspicuous surface damage and debris of the used carbon fibres. The results of the present study indicate that (i) ERL does not damage titanium surfaces and subsequently does not influence the attachment rate of SAOS-2 cells, and (ii) VS, used with this type of carbon fibre tip, does not seem to be suitable for the instrumentation of titanium surfaces.

In addition to conventional treatment modalities (mechanical and chemical), the use of lasers has been proposed for cleaning and detoxification of implant surfaces. The aim of the present clinical investigation was (1) to evaluate the effects of an Er:YAG laser on the surface properties of titanium implants in vivo and (2) to determine the effectiveness of this treatment modality for subgingival calculus removal. This investigation was conducted on eight implants of two patients, considered for explantation due to severe peri-implantitis inflammation. Immediately before explanatation, six implants were instrumented subgingivally with an Er:YAG laser (100 mJ/pulse and 10 Hz). Two implants served as a control. All titanium implants were examined using scanning electron microscopy by one calibrated and blinded examiner. In comparison to the untreated control group, non-surgical instrumentation of titanium implants with an Er:YAG laser resulted in an effective removal of subgingival calculus without leading to any thermal damages. However, all samples of the test group revealed amounts of residual debris which should be taken into account under clinical conditions.