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Tooth extractions can result in alveolar bone dimensional changes, necessitating additional bone grafting for implant placement. Alveolar ridge preservation (ARP) aims to counteract postextraction changes. This case series evaluates the bone regenerative properties of a freeze-dried bone allograft (FDBA) and the clinical outcomes of implants in grafted extraction sites. A total of 33 patients were enrolled, undergoing single/multiple tooth extractions followed by ARP. Biopsy samples were harvested during implant placement for histologic and histomorphometric analysis. Clinical outcomes included marginal bone loss and pink esthetic score (PES). Twenty-five patients completed the study. FDBA-augmented sockets exhibited new bone formation adjacent to graft particles. Implants (n = 25) showed 100% survival and success rates at 1 and 2 years. PES improved significantly over time (P < .001), while marginal bone loss did not significantly differ at 1 and 2 years (P = .096). Specimens showed trabecular bone, residual FDBA particles, and marrow spaces. High magnification revealed immature bone and woven bone bridges around graft particles. No inflammatory cells were observed. This case series provides valuable insights into ARP performed with FDBA (as implants were placed after 3 months of healing without any additional bone augmentation), the histologic outcomes were favorable, and implants were successful after a 2-year follow-up period. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the influence of immediate loading on the osseointegration and bone density of implants placed in a healed alveolar bone crest and supporting single crowns. Materials and Methods: Two solid titanium transmucosal mini-implants were placed in the distal regions of the mandible in 14 patients. One mini-implant was immediately functionally loaded, whereas the other was left unloaded. After 2 months of healing, biopsy samples were retrieved and the levels of new bone, old bone, and total bone (new + old) were assessed. Results: Histologic examination was performed on biopsies from 12 patients (n = 12). The new bone-to-implant contact percentage (BIC%) was 40.3% ± 16.8% and 55.1% ± 19.1% (P = .043) at the unloaded and loaded sites, respectively; in addition, the total BIC% was 44.9% ± 17.0% and 59.5% ± 18.8%, respectively (P = .034). The new bone density was 45.9% ± 11.6% for the unloaded implants and 45.9% ± 16.7% for the loaded implants (P = .622). Conclusions: Immediate loading had a positive effect on bone apposition at the implant surface, but no effect on bone density was observed after 2 months of healing. [ABSTRACT FROM AUTHOR]

The primary aim of this study was to assess the histomorphometric outcomes of extraction sockets grafted with freeze-dried bone allograft (FDBA) and sealed with a collagen membrane after 3 months of healing in specific region of interest (ROI) areas. The secondary aims were to analyze the biomaterial resorption rate, the bone-to-biomaterial contact (BBC), and the area and perimeter of grafted particles compared with commercially available FDBA particles. Fifteen patients underwent tooth extractions and ridge preservation procedures performed with FDBA and a collagen membrane. Bone biopsy samples were harvested after 3 months at the time of implant placement for histologic and histomorphometric analysis. Two areas of concern (ROI1 and ROI2) with different histologic features were identified within the biopsy samples; ROI1, ROI2, and commercially available particles were analyzed and compared. The following parameters were analyzed: newly formed bone, marrow space, residual graft particles, perimeter and area of FDBA particles, and BBC. The histomorphometric analysis showed 35.22% ± 10.79% newly formed bone, 52.55% ± 16.06% marrow spaces, and 12.41% ± 7.87% residual graft particles. Moreover, the histologic data from ROI1 and ROI2 showed that (1) the mean percentage of BBC was 64.61% ± 27.14%; (2) the newly formed bone was significantly higher in ROI1 than in ROI2; (3) the marrow space was significantly lower in ROI1 than in ROI2; and (4) the FDBA particles in ROI1 sites showed significantly lower area and perimeter when compared to commercially available FDBA particles. This latter data led to the hypothesis that FDBA particles embedded in newly formed bone undergo a resorption/remodeling process. [ABSTRACT FROM AUTHOR]

Bone blocks are proposed in oral bone regeneration for their biocompatibility and osteoconductivity. Human dental pulp stem cells (hDPSCs) have been used with bone substitutes as a biocomplex. Melatonin, produced by the pineal gland, has specific functions in the oral cavity in bone remodeling and enhancing the dual actions on osteoblasts and osteoclasts, the genic expression of bone markers. This study evaluated the osteogenic differentiation of hDPSCs, stimulated by melatonin on equine bone blocks. hDPSCs were cultured in growth medium (GM) or differentiation medium (DM) with or without the presence of equine bone blocks and 100 µm melatonin. After 7, 14, and 21 days of culture, expression of miRNAs (miR-133a, miR-133b, miR-135a, miR-29b, miR-206, and miR- let-7b) and genes (RUNX2, SMAD5, HDAC4, COL4a2, and COL5a3), osteocalcin levels and histolgic analyses were evaluated. Melatonin and equine blocks increased the osteogenic potential of hDPSCs even in GM, regulated miRNA and gene expression related to osteogenesis, and increased osteocalcin. hDPSCs cultured in DM showed a significantly higher osteogenic potential compared to GM. This study suggests that equine bone blocks and melatonin enhanced osteogenesis, stimulating early stages of cell differentiation. hDPSCs/equine bone block and melatonin represent a promising, useful biocomplex in bone regeneration with a potential for a possible clinical application. Int [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare the Streptococcus oralis biofilm formation on titanium machined turned surfaces and sandblasted surfaces that were previously characterized for their superficial topographies. Materials and Methods: Two commercially pure titanium surfaces were analyzed and compared: machined (turned surfaces subjected to a process of decontamination that also included a double acid attack) and sandblasted (sandblasted surfaces, cleaned with purified water, enzymatic detergent, acetone, and alcohol). The characterization of the samples at the nanolevel was performed using atomic force microscopy, which permitted calculation of the superficial nanoroughness (Ra). The sessile drop method was used to measure the water contact angle in both groups and allowed information to be gained about their wetting properties. Scanning electron microscope and energy-dispersive x-ray spectroscopy analysis allowed comparison of the microtopographic geometry and the chemical composition of the samples. Then, the disks were preincubated with saliva in order to form an acquired pellicle. Streptococcus oralis was put on the disks, and both groups were tested at 24 and 48 hours for biofilm biomass evaluation, colony-forming units (CFUs), and live/dead staining for cell viability. Results: The sandblasted samples were characterized by a significantly higher level of superficial oxides, superficial roughness, and hydrophilicity, compared with the machined turned samples. Although there were topographic differences, the Streptococcus oralis biofilm formation, quantified in CFUs, and biomass formation at 24 and 48 hours were similar in both groups. With the live/dead staining, the sandblasted disks were characterized by an increased percentage of dead cells compared with the machined disks. Conclusion: Although significant topographic differences were present between machined and sandblasted disks, the Streptococcus oralis biofilm formation seems to not be significantly affected. [ABSTRACT FROM AUTHOR]

Bone density and implant primary stability parameters have been introduced that are based on calculating (1) the average of the instantaneous torque needed to keep the rotation speed of a bone density probe constant while it descends into bone or (2) the integral of the instantaneous torque-depth curve at implant insertion (I), a quantity that is equal to the insertion energy multiplied by a constant. This study aimed to determine how these two quantities are affected by the presence and thickness of a cortical bone layer. Materials and Methods: An instantaneous torquemeasuring micromotor was used to measure the density of six double-layer polyurethane foam blocks mimicking different cortical/cancellous bone combinations. Twenty measurements per block were collected, averaged, and compared. The insertion torque and the integral (I) of the instantaneous torque-depth curve at implant insertion were recorded when 20 3.75 × 12-mm cylindrical implants were inserted in each of nine blocks, including three single-layer blocks simulating the absence of a cortical layer, under three final cortical (countersink) preparations: 4.0, 3.7, and 3.5 mm. The relationship between the insertion torque, the integral of the instantaneous torque-depth curve at implant insertion (I), cortical thickness, and the final diameter preparation were investigated with regression and best-fit slope analyses. Results: Bone density measurements showed that the average of the instantaneous torque at probing allowed differentiation of five of six different bone classes (hard-hard, hard-normal, hard-soft, normal-normal, normal-soft, soft-soft); the post hoc analysis of variance (ANOVA) comparisons were all statistically significant except for the hard-soft–normal-soft pair. The insertion torque and the integral (I) of the instantaneous torque-depth curve at implant insertion increased proportionally with cortical bone thickness (Pearson’s r > 0.96 in all cases). Conclusion: When the final preparation varied from 3.7 mm to 3.5 mm, the insertion torque–thickness plot slope did not change significantly, while that of the instantaneous torquedepth curve integral (I)–thickness plot did change, suggesting that the torque-depth curve at implant insertion integral (I) may detect the increase in implant stability consequent to slight anatomical changes or changes in the site preparation protocol better than the insertion torque when measuring the cortical bone layer stress while undergoing insertion. These findings concerning bone density and primary stability should be investigated further using different experimental settings. If confirmed, they might generate improvements in the predictability of implant and prosthetic rehabilitation outcomes. [ABSTRACT FROM AUTHOR]

For decades, the histologic evidence about osseointegration and the bone-implant interface has been discussed in the literature. In this review, the effectiveness of dental implants retrieved for different causes was evaluated. A literature search was performed in databases for papers about implants retrieved from humans published by the Implant Retrieval Center of the University of Chieti-Pescara, Italy. Sixty-eight articles were selected into categories based on topics. The data indicated high level of bone-to- implant contact, lamellar bone close to the surface, roughness related to an increased bone response, organized and remodeled bone after loading, and peri-implant interfaces subjected to a continuous dynamic function. [ABSTRACT FROM AUTHOR]

This investigation was designed to evaluate the reestablishment of bone-to-implant contact on infected dental implant surfaces following decontamination with an erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser and reconstructive therapy. Three patients presenting with at least one failing implant each were enrolled and consented to treatment with the Er,Cr:YSGG laser surface decontamination and reconstruction with a bone replacement allograft and a collagen membrane. The laser treatment was carried out at a setting of 1.5 W, air/water of 40%/50%, and pulse rate of 30 Hz. At 6 months, all three patients returned for the study. En bloc biopsy samples of four implants were obtained and analyzed. Two patients had excellent clinical outcomes, while one patient with two adjacent failing implants experienced an early implant exposure during the follow-up period. There was histologic evidence of new bone formation with two implant specimens and less bone gain with the others. Despite the small sample size, these were optimistic findings that suggested a positive role of Er,Cr:YSGG laser in debridement of a titanium implant surface to facilitate subsequent regenerative treatment. This investigation provides histologic evidence as well as encouraging clinical results that use of the Er,Cr:YSGG laser can be beneficial for treatment of peri-implantitis, but further long-term clinical studies are needed to investigate the treatment outcome obtained. [ABSTRACT FROM AUTHOR]

Purpose: A barrier membrane consisting of an equine-derived, demineralized cortical bone sheet has been made available, yet evidence of its effectiveness is currently only anecdotal. This study aimed to obtain preliminary evidence concerning the medium-term prosthetic and implant success rates that may be achieved when such a membrane is used in combination with an equine, enzyme-treated bone graft, concomitantly to implant placement in the esthetic zone. Materials and Methods: Records of patients who had one or two implants placed in the anterior sectors of the two arches and had peri-implant bone regeneration carried out using the equine-derived membrane and equine-derived collagen-preserving bone granules were retrospectively collected. Peri-implant marginal bone loss (MBL) was used to assess implant survival. When available, histologic data concerning the equine membrane and cone beam computed tomography (CBCT) scans were analyzed as well. Results: Records of 32 patients (ages 36 to 73 years), corresponding to 44 implants placed, were retrieved and analyzed. The mean follow-up was 113.9 ± 10.2 months. Two implants failed. The implant success rate was 90.9%. Twelve membrane samples could be retrieved and analyzed, showing the membrane was still occlusive at 4.2 ± 1.1 months and only beginning to undergo remodeling. Twelve CBCT scans showed that 65.1 ± 9.8 months after surgery, a newly formed cortical layer could be observed in the zone that had undergone grafting. Conclusion: The equine cortical bone membrane and the enzyme-treated bone graft used in this case series achieved a medium-term implant and prosthetic success rate that was not dissimilar to that of other resorbable membranes and grafts for peri-implant guided bone regeneration augmentation. Preliminary medium-term histologic and CBCT data suggest that the membrane may be occlusive for a period of at least 4 months and may contribute to preserve the ridge thickness over time. [ABSTRACT FROM AUTHOR]

To evaluate the osseointegration of mini-implants placed in grafted sinuses with lateral windows of two different dimensions. Materials and Methods: Sinus floor augmentation was performed in volunteers using a lateral window. The antrostomy was systematically prepared with a height of either 8 mm (large group) or 4 mm (small group). After 6 months of healing, mini-implants were placed in the grafted region. Biopsy specimens including the mini-implants were harvested 3 months after placement. Results: Twenty biopsy specimens, 10 from each group, were suitable for the histologic analysis. Similar amounts of new bone-to-implant contact were obtained in both the large (41.1% ± 19.5%) and the small (42.8% ± 13.2%) groups (P = .940). Small percentages of residues of xenograft were found in contact with the implant surface, with 0.6% ± 1.1% in the large group and 5.9% ± 9.5% in the small group (P = .098). The new bone density around the implants was 31.7% ± 8.2% and 34.0% ± 7.9% in the large and small groups, respectively (P = .623).Conclusion: The dimensions of the antrostomy did not influence the histologic healing of implants placed 6 months after sinus floor augmentation. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate histomorphometrically early healing at implants placed in sites prepared with either a sonic device or conventional drills. Materials and Methods: Sixteen volunteer patients were recruited. Two titanium mini-implants were placed in the distal segments of the maxilla in recipient sites prepared with either a sonic device or conventional drills. Biopsy specimens containing the mini-implants were retrieved after 2 weeks in eight patients, and after 6 weeks in the other eight patients. Histomorphometric analyses were performed. Results: Histologic slides were available from seven patients for both 2-week and 6-week periods. After 2 weeks of healing, small amounts of new bone were found in contact with the implant surface, with 5.5% ± 7.3% and 3.8% ± 10.0% at the sonic and drill groups, respectively. After 6 weeks of healing, new bone was 46.9% ± 15.5% at the sonic group, and 46.4% ± 14.9% at the drill group. None of the differences was statistically significant. Conclusion: The percentage of new bone in contact with the implant surface was similar in the sonic and drill groups. [ABSTRACT FROM AUTHOR]

The aim of the present study was a histologic and histomorphometric analysis of the peri-implant tissue reactions and of the bone-titanium interface in successfully osseointegrated, clinically stable, and immobile retrieved titanium dental implants after a long loading period. Four successfully osseointegrated and stable implants with a sandblasted surface were retrieved from a patient due to fracture, two after 14 years of loading and two after 17 years. None of these implants has been previously reported. Mature, compact bone with a few marrow spaces was observed around all four implants. At low magnification, a high percentage of bone-implant contact (BIC) was present at the interface of almost all implants. BIC percentage for the four implants was 83%, 66%, 74%, and 65%. In almost all the implants, the space within the threads was almost completely filled by compact bone. Close, tight contact between bone and implant surface was observed in all specimens, and no gaps or fibrous connective tissue was found at the boneimplant interface. All implants appeared to be well integrated in the surrounding mineralized bone, and all showed adequate BIC percentages after a long loading history. [ABSTRACT FROM AUTHOR]

The aim of this study was to analyze the degree of mineralization around nine clinically stable titanium dental implants retrieved after 2 months to 17 years for mechanical complications from five patients. The micromorphology and microchemistry of the interface bone at the coronal and apical sides of the threads were analyzed by environmental scanning electron microscope and energydispersive X-ray spectroscopy (EDX) on histologic samples. Mineralization was investigated by atomic calcium-to-nitrogen (Ca/N), phosphorous-to-nitrogen (P/N), and calcium-to-phosphorous (Ca/P) ratio evaluation (statistical analysis by two-way analysis of variance with Student-Newman-Keuls; P < .05). EDX showed higher Ca/N, P/N, and Ca/P values for the bone at the coronal side compared to the apical side of the threads in the long-term (≥ 14 years) samples. The two most significant findings were that (1) the interface bone located at the coronal side of the implant threads was generally more mineralized than the interface bone located at the apical side, and (2) the mineralization of the peri-implant bone at the interface increased over time. A higher degree of mineralization was found at 2 months in an immediately loaded implant when compared to the 2-month submerged unloaded control, likely related to the different remodeling events (coronal vs apical side of the implant threads) due to the direction of the loading forces. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate histologically and histomorphometrically the effect of a delayed load on healing at implants with a moderately rough surface. Materials and Methods: Two solid titanium screw-shaped devices, 5 mm long and 3.5 mm in diameter, were inserted in the distal segments of the alveolar ridge of 16 volunteer patients in a nonsubmerged fashion. After 2 months, one implant was loaded, while the other was left unloaded. After 2 months, the two implants were collected from 10 patients using a sonic instrument, and ground sections were prepared from the biopsy specimens. Histomorphometric analyses were performed. Results: After 4 months of healing, biopsy specimens from 10 patients were available for analyses (n = 10). The total bone-to-implant contact percentage was 86.8% ± 6.5% and 84.6% ± 3.7% for loaded and unloaded implants, respectively. New bone was represented by 85.5% ± 6.7% and 83.4% ± 3.9% at the loaded and unloaded sites, respectively. A very small amount of old parent bone was found. The density of the mineralized bone was 76.8% ± 8.3% for the loaded sites and 74.1% ± 10.5% for the unloaded sites. The percentages of new and old bone densities were 69.0% ± 8.3% and 7.8% ± 3.9% at the loaded sites, and 65.9% ± 10.3% and 8.2% ± 4.5% at the unloaded sites, respectively. No statistically significant differences were disclosed. Conclusion: Applying a delayed load to implants supporting single crowns did not yield statistically significant differences, and only a tendency of higher osseointegration and bone density was observed at loaded sites compared with the unloaded sites. [ABSTRACT FROM AUTHOR]

Purpose: The present systematic review and meta-analysis aimed to investigate the available evidence in the literature to answer the following focused question: In partially edentulous arches with reduced bone width, do implants placed after horizontal bone augmentation exhibit differences in survival and success rate compared to narrow-diameter implants placed in native bone? Materials and methods: A population, intervention, comparison and outcome question was defined and an electronic search was conducted using the MEDLINE (via PubMed) and Cochrane Oral Health Group databases to identify all studies analysing the use of standard-diameter implants inserted in regenerated bone or narrow-diameter implants for the rehabilitation of partially or completely edentulous atrophic maxillae and mandibles. Inclusion criteria and quality assessments were established, and studies were selected on this basis. Results: Twenty-four studies met the inclusion criteria and were analysed cumulatively. A comparative meta-analysis was not possible due to the lack of studies directly comparing the two rehabilitation methods in question. A cumulative implant survival rate of 97.80% (1246/1274; pooled proportion 0.984, 95% confidence interval 0.977-0.991) was reported for the narrow implants placed in atrophic ridges, while similar results were obtained for the standard-diameter implants placed in regenerated bone, with a cumulative implant survival rate of 97.94% (1332/1360; pooled proportion 0.983, 95% confidence interval 0.976-0.990). Conclusions: The present systematic review found high and comparable survival rates between narrow- and standard-diameter implants placed in regenerated bone; however, well-designed randomised controlled trials are required to support the hypothesis that both treatment strategies are successful in comparable circumstances. [ABSTRACT FROM AUTHOR]

Purpose: Ridge expansion is used to widen narrow ridges with adequate height for implant placement. This human case series presents the clinical and histologic results of delayed expansion of mandibles by ultrasonic surgery. Materials and Methods: Patients with residual alveolar ridge width between 2.3 and 4.1 mm in the coronal area of the posterior mandible were included in the study. First, four linear corticotomies were carried out by ultrasonic surgical device. Four weeks later, adequate bone expansion with a combination of scalpels, thin chisels, and threaded osteotomes that did not compromise cortical vascularization was performed, and two implants per ridge were inserted. Any gaps were filled with corticospongious porcine biomaterial. Three months after implant placement, healing caps were inserted, and bone cores were harvested from the regenerated areas for histologic analysis. Crestal width was recorded at each surgery. Results: The postoperative course was uneventful in all 32 patients (64 implants) who took part in the study, and the implant success rate was 96.88% at 3 months. The mean increase in ridge width was 5.17 ± 0.86 mm. The histologic specimens showed a mixture of new bone and particles of biomaterial, as well as newly formed bone. Histomorphometry demonstrated that 64% ± 3.1% of the specimen was composed of newly formed bone, 8% ± 0.8% was made up of marrow spaces, and 27% ± 2.6% comprised the residual grafted biomaterial. Conclusion: This study showed that mandibular ridge expansion using a delayed split-crest technique by means of ultrasonic surgery and association with biomaterial led to good horizontal bone gain, with no fractures of the buccal plate, and a high implant success rate. The histologic specimens showed newly formed bone and good integration of the biomaterial. [ABSTRACT FROM AUTHOR]

The aim of this case series was a clinical, histologic, and histomorphometric evaluation of calcium carbonate in sinus elevation procedures. Sinus augmentation was performed in the atrophic maxillae of 24 subjects using calcium carbonate. Six months after the regeneration procedures, 68 implants were placed and clinically followed for 1 to 5 years, depending on the placement timing. At the last implant placement procedure, 8 bone cores were harvested and processed for histology. After a 6-month healing period, sinuses grafted with calcium carbonate showed a mean vertical bone gain of 6.93 ± 0.23 mm. The histomorphometric analysis revealed 15% ± 3% residual grafted biomaterial, 28% ± 2% newly formed bone, and 57% ± 2% marrow spaces. The implant survival rate was 98.5%. It can be concluded that calcium carbonate was shown to be clinically suitable for sinus elevation procedures after 1 to 5 years of follow-up and histologically biocompatible and osteoconductive. [ABSTRACT FROM AUTHOR]

Direct laser metal forming (DLMF) is a procedure in which a high-power laser beam is directed on a metal powder bed and programmed to fuse particles according to a computer-aided design file, thus generating a thin metal layer. With DLMF, it is now possible to fabricate dental implants with a superficial porous surface. The aim of the present study was to evaluate the peri-implant soft tissues around human-retrieved DLMF dental implants. Collagen fibers, in the form of bundles, were oriented perpendicularly to a distance of 100 μm from the surface, where they became parallel, running in several directions. In some portions, only a few collagen fiber bundles appeared to be oriented perpendicularly or obliquely to the plane of the section. Collagen fibers appeared to form a dense chaotic three-dimensional network running in different, more or less parallel directions to the surface. Under scanning electron microscopy, an intimate contact of the fibrous matrix with the implant surface was evident, and some collagen bundles could be seen to bind directly to the metal surface. By changing the surface microtexture, it was possible to change the response of the peri-implant soft tissues. [ABSTRACT FROM AUTHOR]

This investigation was designed to evaluate the histologic healing pattern of two Miller Class III recession defects associated with noncarious cervical lesions (NCCLs) treated with a connective tissue graft (CTG) and coronally advance flap (CAF). One patient presenting with two teeth predetermined to be surgically extracted was enrolled and consented to treatment. One month after phase I treatment, a full-thickness flap was reflected and the NCCLs treated with a compomer restoration; at the same time, a CTG was harvested from the palate and positioned over the compomer restoration. The flap was then coronally repositioned. After 4 months of healing, an en bloc biopsy extraction of the two teeth was executed. The teeth were analyzed histologically to assess the periodontal wound healing. A long junctional epithelial attachment was noted throughout the major portion of the restored surface. Only minimal signs of connective adhesion and new bone formation could be seen in the apical portion of the restored area, without signs of root resorption or ankylosis. This report provides evidence that the presence of a compomer restoration allowed the formation of a long juctional epithelium after CTG and CAF treatment. [ABSTRACT FROM AUTHOR]

Purpose: This human study sought to compare, from an immunohistochemical point of view, matrix metalloproteinases (MMPs) 2, 3, 8, 9, and 13 in the soft tissues around titanium and zirconium oxide healing caps. Materials and Methods: Five patients participated in this study. All patients received 3.8 × 11-mm dental implants, which were left to heal in a nonsubmerged (single-stage) mode. Healing caps (3.8 mm in diameter and 3.0 mm in height) were inserted in all implants. Half of the implants were randomly supplied with standard, prefabricated caps of commercially pure titanium (control), while the other half were randomly provided with zirconium oxide caps (test). After a 6-month healing period, gingival biopsy specimens were obtained with a circular scalpel around the healing caps of both groups, without unscrewing or removing the healing caps, and the samples underwent immunohistochemical processing for MMPs 2, 3, 8, 9, and 13. Results: Statistically significant differences were found in the values of MMP-8 in the cells of the inflammatory infiltrate, with higher values for the titanium samples. Statistically significantly higher values were found, also in the titanium samples, for MMP-9 in the endothelial cells of the blood vessels. No statistically significant differences were found for any other MMPs. Conclusions: The present results showed that the soft tissues around titanium healing caps underwent a higher rate of restorative processes, most probably correlated to the MMP levels observed in the tissues. [ABSTRACT FROM AUTHOR]

The aim of this study was to histologically and histomorphometrically analyze the peri-implant tissue reactions and the bone-titanium interface in loaded Ankylos implants retrieved after loading periods of longer than 1 year. The archives of the Implant Retrieval Center of the Dental School of the University of Chieti- Pescara were searched for Ankylos implants retrieved from humans after a loading period of longer than 1 year. A total of four implants were found: one had been retrieved after 3 years (Friadent plus surface), two after 3.5 years (Friadent plus surface), and one after 10 years (Deep Profile surface). All implants had been loaded; two had been loaded immediately. One implant was retrieved after fracture, one was retrieved after fracture of the superstructure, and the other two were retrieved because of bone resorption with or without infection. Compact bone with few small marrow spaces was present around the three implants retrieved after 3 and 3.5 years; trabecular bone was present around the implant retrieved after 10 years. The bone-implant contact of the three best threads was 35% for the implant retrieved after 10 years, 99% for the implant retrieved after 3 years, and 100% for the implants retrieved after 3.5 years. No untoward effects were present at the interface, and a high bone-implant contact was present around the implants with the microstructured surface. The data show that these implants had the potential to maintain osseointegration under long-term function with continuous and ongoing bone remodeling. [ABSTRACT FROM AUTHOR]

This case report presents a histologic and histomorphometric evaluation of the peri-implant tissues of a HA-coated implant retrieved due to peri-implantitis after a 10-year loading period. The implant was retrieved with a trephine and treated to obtain thin ground sections. At low-power magnification, mostly compact, mature bone with small marrow spaces could be observed at the interface with the implant. The coating was always present in the areas where bone was detected, the bone was always in close contact with the coating, and there was no detachment between the metal and coating or between the coating and bone. Areas of bone remodeling were demonstrated by the presence of many secondary osteons and reversal lines close to the implant surface. The bone-implant contact percentage was 36.3% ± 1.2%. The percentage of the implant surface covered by the HA coating without bone, where bone may have detached during retrieval, was 32.6% ± 2.8%. This HA-coated implant continued to demonstrate more than adequate BIC after many years of function and the potential to maintain osseointegration in the long term. [ABSTRACT FROM AUTHOR]

The aim of the present study was a light and scanning electron microscopy (SEM) evaluation of the peri-implant tissues around sandblasted, acid-etched implants, retrieved from man, after a loading period of 5 and 10 years, respectively. Two implants (Leone Implant System) had been retrieved for a fracture of the prosthetic superstructure respectively after 5 and 10 years of loading. Both implants were stable before retrieval and had been retrieved using a 5-mm trephine bur. One implant was treated to obtain thin ground sections, while the other underwent evaluation under SEM. Compact, mature lamellar bone was present over most of the implant perimeter in close contact with the implant surface and with many remodeling areas. Under SEM, small concavities, completely filled by mineralized bone, were present on the implant surface. The present histologic results showed that these implants were well integrated over the long term, and the peri-implant bone was undergoing continuous remodeling at the interface. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the clinical and histologic aspects of bone formation in maxillary sinus augmentation using macroporous biphasic calcium phosphate (MBCP) comprising hydroxyapatite/tricalcium phosphate (HA/TCP) 60/40 as bone-grafting material. Materials and Methods: A total of 10 patients and 12 sinuses grafted with MBCP in two-stage sinus augmentation were included in the present study. After a healing period of 6 months, bone core biopsies were harvested during implant insertion and evaluated under light microscopy. Results: The histologic examination showed that the MBCP particles were in close contact with new bone in all biopsies. Histomorphometric evaluation demonstrated that newly formed bone constituted 28.3% ± 2.7%, residual grafted material 27.3% ± 1.2%, and marrow spaces 45.9% ± 1.9%. Conclusions: Histologic investigation showed that the MBCP grafted particles were embedded and integrated in the newly formed bone; this bone was in close and tight contact with the biomaterial particles. Data from the preliminary results demonstrated that MBCP is a biocompatible and osteoconductive material that can be successfully used as a grafting material for sinus floor augmentation. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate the performance of piezoelectric devices during sinus elevation to determine the percentage of sinus membrane perforation and the time required to perform the antrostomy and elevation of the membrane. A total of 35 patients and 40 grafted sinuses were included. The parameters recorded were bony window length and height, bone thickness, osteotomy area, operative time, and number of perforations. Seven (17.5%) membrane perforations were observed, which were repaired with resorbable membranes. The mean length, height, and thickness of the osteotomy were 13.8 ± 2.9 mm, 6.9 ± 1.4 mm, and 1.4 ± 0.4 mm, respectively. The mean osteotomy area was 96.8 ± 32.2 mm2, and the mean operative time was 10.3 ± 2.1 minutes. This study demonstrated that a piezoelectric device could be an attractive alternative for successful sinus augmentation. [ABSTRACT FROM AUTHOR]

The aim of this study was to measure implant stability quotient (ISQ) values in grafted sites during 5 years of follow-up. Sixteen patients received a total of 36 implants inserted in sites treated with autologous bone (group A) or porcine bone in addition to autologous bone (group B). In both groups, resonance frequency analysis (RFA) values increased during the observation period. At 2 months, statistical analysis showed significantly lower ISQ values for group B than for group A (P = .0134) and significantly higher ISQ values in the mandible than in the maxilla (P = .0251). RFA measurements suggested stable long-term results for implants inserted in both groups. [ABSTRACT FROM AUTHOR]

Few histologic and histomorphometric reports are present in the literature regarding the peri-implant bone response around implants inserted in sinuses grafted with different biomaterials. Anorganic bovine bone (ABB) and anorganic bovine matrix with the addition of an active cell-binding peptide (PepGen P-15) are xenogenic materials that have been reported to present biocompatibility and osteoconductivity. A monolateral sinus augmentation procedure with ABB (50%) and PepGen P-15 (50%) was performed in a 54-year-old man. Two titanium implants with a sandblasted and acid-etched surface were inserted after 6 months. After an additional 6 months, a fixed prosthetic restoration was fabricated. One implant fractured in the coronal portion after an 8-year loading period and was removed using a 5-mm trephine bur. Few particles of both grafting materials were present in the peri-implant bone. No graft material particles were found in contact with the implant surface, and bone was always interposed between the graft materials and surface. No inflammatory cell infiltrate, multinucleated giant cells, or foreign body reaction cells were found. The tissues around the implant were composed of 51.4% ± 4.8% bone, 6.2% ± 0.7% ABB particles, 2.4% ± 0.5% PepGen P-15, and 40.0% ± 7.1% marrow spaces. The bone-implant contact percentage was 78.4% ± 4.1%. A sinus augmentation procedure using ABB and PepGen P-15 produced bone formation with subsequent implant osseointegration, which was still present after 8 years of implant loading. [ABSTRACT FROM AUTHOR]

Among the graft materials that can be used clinically, xenografts are the most common. Xenografts are of bovine, porcine, or equine origin and require the complete removal of proteins to avoid immunologic problems and the risk of transmission of prions, viruses, etc. Protein destruction can be achieved by a chemical procedure using organic solvents and heat treatment. After this process, a carbonated hydroxyapatite similar to human bone remains. The aim of this case report is to investigate the bone formation in a sinus augmentation procedure using a high temperature-treated bovine porous hydroxyapatite. A 58-year-old woman underwent bilateral sinus augmentation using this biomaterial. After 9 months, during stage-two surgery, two core biopsy specimens were retrieved and treated to obtain thin ground undecalcified sections. Microscopically, newly formed bone was present at the interface with most particles. The major portion of the particles appeared to be completely lined and surrounded by bone. No obvious signs of resorption were present on the biomaterial surface. No gaps or connective tissue were present at the bone-biomaterial interface. No inflammatory infiltrate or fibrous encapsulation of the particles was present. Histomorphometry showed that the percentages of newly formed bone, residual grafted particles, and marrow spaces were 25.1% ± 2.3%, 37.3% ± 1.1%, and 38.5% ± 3.1%, respectively. The excellent properties demonstrated by Endobon are probably a result of its particular hydroxyapatite porous microstructure with a high percentage of interconnected micropores that promote the ingrowth of osteogenic cells and vessels, making graft integration easier and faster. [ABSTRACT FROM AUTHOR]

Most of the histologic studies found in the literature on the peri-implant soft tissues have been done in animals and usually have been confined to mandibular implants fitted with healing or standard abutments. Few studies have investigated human peri-implant soft tissues. Moreover, the structure and dimensions of the peri-implant soft tissues in immediately loaded implants have not been investigated in depth. Human histologic data are valuable to validate animal models. This histologic and histomorphometric study evaluated the peri-implant soft tissues around three immediately loaded implants in humans. The implants were retrieved using a trephine and treated to obtain thin, ground sections. The sulcular epithelium was composed of approximately four to five layers of parakeratinized epithelial cells and had a length of approximately 1.2 to 1.3 mm. The junctional epithelium was composed of approximately three to four layers of epithelial cells and had a length of approximately 1.0 to 1.5 mm. Connective tissue attachment had a width of between 400 and 800 µm. Peri-implant collagen fibers, in the form of bundles (1- to 5-µm thick), began at the crestal bone and were oriented perpendicular to the abutment surface until 200 µm from the surface, where they became parallel running in several directions. Collagen fibers appeared to form a three-dimensional network around the abutment. No acute or chronic inflammatory cell infiltrate was present. Collagen fibers oriented in a perpendicular manner and in direct contact with the abutment surface were not observed in any of the specimens. This differentiated network of fibers may have clinical relevance as a mechanical protection of the underlying bone. These human histologic data are extremely valuable to validate and confirm those obtained from studies performed on animal models. Moreover, immediate loading of the implants did not compromise soft tissue integration. [ABSTRACT FROM AUTHOR]

Purpose: Algipore is a biologic hydroxyapatite derived from calcifying maritime algae. The present study evaluated this material histologically and histomorphometrically after implantation in rabbit tibia defects for 4 weeks. Materials and Methods: Six New Zealand rabbits were used in this study. In each rabbit tibia, two 7-mm defects were prepared. Control defects were left empty, and test defects were filled with Algipore. Twenty-four specimens (12 test and 12 control) were retrieved and processed for histology. Results: In control sites, newly formed trabecular bone with large marrow spaces was plentiful in the most peripheral areas of the defects but sparse elsewhere. In contrast, in test sites, a large quantity of newly formed bone around the biomaterial particles was detected in the central medullary portion of the defect. In addition, in several areas, the biomaterial particles were bridged by newly formed bone. The percentage of contact between newly formed bone and biomaterial particles was 71.2% ± 9.8%. Inside the central portion of the biomaterial particles, it was possible to see newly formed bone (about 35.3% ± 4.8% in each particle). In test sites, newly formed bone represented 31.1% ± 1.9% of the material, with residual biomaterial particles occupying 33.4% ± 2.8% and marrow spaces another 34.7% ± 4.3%. In the control sites, the values were 30.2% ± 2.2% for newly formed bone and 68.7% ± 4.1% for marrow spaces. A statistically significant difference was found in the percentage of marrow space between the two groups, but no significant difference was observed in the percentage of newly formed bone. Conclusions: The present rabbit study confirmed the high osteoconductivity and resorbability of this biomaterial. [ABSTRACT FROM AUTHOR]

Surface roughness is important for implant osseointegration. It has mostly been assessed by amplitude and height descriptors. Fractal analysis is derived from fractal geometry and is used to describe the organization of objects found in nature, quantifying their shape complexity with a value. Fractal dimension (Df ) is an index of the space-filling properties of an object and can be used as a parameter that describes the organization of surface roughness. The greater the Df value, the more chaotic the surface topography. The aim of this study was to assess the Df of implants with three different surface topographies to evaluate whether a novel method to measure roughness of implant surface topography could be developed. Forty-five disk-shaped samples (10 × 2 mm) with three different surface topographies were analyzed by scanning electron microscopy: group A, machined surface; group B, sandblasted and acid-etched surface; and group C, sandblasted, acid-etched, and neutralized surface. Images at 20,000× and 50,000× magnification were processed for quantitative analysis of Df using the box-counting method. Df values were correlated to the image magnification. At 20,000× magnification, Df for groups A, B, and C was 1.81, 1.67, and 1.59, respectively. At 50,000× magnification, Df was lower for all examined groups; more specifically, Df was 1.77, 1.59, and 1.42 for groups A, B, and C, respectively. Statistically significant differences were found between groups A and C at both magnifications. Df is used widely and successfully as a measurement to characterize anatomical structures and physiologic and pathologic processes.Df not only provides an index of roughness size values, but also a measure of roughness spatial organization; therefore, it could be a promising method to differentiate between rough surfaces capable of supporting osseointegration. [ABSTRACT FROM AUTHOR]

Objective: Immediate loading of dental implants in the edentulous mandible has proven to be an effective, reliable, and predictable procedure. There is little long-term data available on similar treatments in the edentulous maxilla. The aim of the present study was to clinically evaluate edentulous maxilla rehabilitation with removable prostheses supported by the Ankylos SynCone (Dentsply-Friadent) system. Method and Materials: The treatment method was based on immediate loading of four implants in the completely edentulous maxilla. A total of 180 implants were inserted in 45 patients. Dentures were placed on and retained by prefabricated conical crowns that were inserted into the existing denture base by direct intraoral polymerization immediately after surgery and supported by corresponding conical primary implant abutments. Results: During the observation period, two implants (1.11%) were removed due to the lack of osseointegration. One implant was removed due to peri-implantitis, and one other (0.55%) implant was removed because of a fracture after 6 months of function. The overall implant survival rate was 97.77%, while the prosthesis survival rate was 100%. Swelling or suppuration was not observed. After a total observation period of 26.7 months (range 12 to 54 months), all implants had healthy peri-implant soft tissue that showed low values of clinical parameters. Only seven implants (3.97%) presented a sulcus bleeding index of 3. Conclusion: This method facilitates edentulous maxilla rehabilitation with removable prostheses. The conical crown concept presented resulted in stable complete-denture retention, reduced denture base, and improved oral hygiene. [ABSTRACT FROM AUTHOR]

A 53-year-old woman underwent bilateral reconstruction of her severely atrophic posterior mandible using inlay inorganic bovine bone block grafting. Four months later, a bone specimen was taken for histologic evaluation and eight dental implants were placed. These implants were loaded with a provisional prosthesis after another 4 months. When the definitive prosthesis was inserted 8 months postsurgery, all implants were osseointegrated. Histologic analysis showed that the grafted bone was lined with newly formed bone. The results indicate that inorganic bovine bone blocks might serve as an alternative to autogenous grafting for posterior mandibular augmentation using the inlay technique. (Int J Periodontics Restorative Dent 2010;30:583-591.). [ABSTRACT FROM AUTHOR]

A 53-year-old woman underwent bilateral reconstruction of her severely atrophic posterior mandible using inlay inorganic bovine bone block grafting. Four months later, a bone specimen was taken for histologic evaluation and eight dental implants were placed. These implants were loaded with a provisional prosthesis after another 4 months. When the definitive prosthesis was inserted 8 month spostsurgery, all implants were osseointegrated. Histologic analysis showed that the grafted bone was lined with newly formed bone. The results indicate that inorganic bovine bone blocks might serve as an alternative to autogenous grafting for posterior mandibular augmentation using the inlay technique. [ABSTRACT FROM AUTHOR]

Objectives: Retention of mandibular complete dentures on two or four interforaminal implants is considered the most reliable procedure in implant therapy. There are different retention elements available for all implant systems. The aim of the present study was to clinically evaluate patients with a mandibular overdenture supported by the Ankylos SynCone system (Dentsply). Method and Materials: Thirty-nine patients were treated with 156 implants. The treatment method was based on immediate loading of four interforaminal implants without the use of a bar retainer. The denture was placed on and retained by prefabricated conical crowns that were inserted into the existing denture base by direct intraoral polymerization immediately after surgery and supported by the corresponding conical primary implant abutments. Results: The cumulative implant survival rate was 98.7% (two failures), while the prosthesis survival rate was 100%. After a total observation of 30.3 months (range 12 to 60 months), all other implants presented healthy peri-implant soft tissue conditions showing low value of clinical parameters. Conclusion: This method facilitates secondary splinting of the inserted complete denture. The conical crowns concept presented here resulted in stable complete denture retention, reduced the denture base, and improved oral hygiene. [ABSTRACT FROM AUTHOR]

Purpose: This prospective clinical study evaluated the incidence of abutment loosening of Morse taper—connection implants used for single-tooth replacement. In addition, the cumulative survival rate and the implant/crown success were evaluated. Materials and Methods: Implants were evaluated 12, 24, 36, and 48 months after insertion. The incidence of abutment loosening, modified Plaque Index, modified Sulcus Bleeding Index, probing depth, distance from the implant-crown margin to the coronal border of the peri-implant mucosa, width of keratinized mucosa, and the distance between implant shoulder and first bone-implant contact (DIB) were assessed. The cumulative survival rates were calculated with Kaplan-Meier estimates. Implant/crown success criteria included absence of abutment loosening, absence of suppuration and mobility, probing depth < 5.0 mm, and DIB < 1.5 mm after 12 months and not exceeding 0.2 mm for each following year. Results: Over a 4-year period (2003-2007; mean follow-up per implant: 30.79 months), 307 implants (162 maxillary, 145 mandibular) were inserted in 295 patients (125 men and 170 women aged between 24 and 79 years) at six different clinical centers. The sites included anterior (n = 115) and posterior (n = 192) teeth. At the end of the study, a very low percentage of implant-abutment loosening (0.66%) was found, with only two loosened abutments. The cumulative implant survival rate was 98.4%. Mean DIB was 1.14 mm (48 months). Only four surviving implants did not meet the criteria for success, and the implant/crown success rate was 97.07%. Conclusion: Based upon this study of 307 implants observed during a 4-year period, Morse taper—connection implants represent a good solution for single-tooth restorations, with a very low incidence of abutment loosening (0.66%). [ABSTRACT FROM AUTHOR]

Purpose: Resonance frequency analysis (RFA) is a quantitative method for the measurement of implant stability. Information about the significance of RFA measurements and the relationship between RFA values and implant osseointegration, success, or failure is important from a clinical point of view. In a previous study the authors observed a strong correlation between RFA values and mineralized boneimplant contact percentage in implants retrieved after 6 months. The aim of the present histologic and histomorphometric study was to determine whether the same correlation existed at earlier time points, specifically in implants retrieved after 4 or 8 weeks. Materials and Methods: Sixteen implants, all with a sandblasted and acid-etched surface, were evaluated in the present study. The implants were retrieved for different reasons after 4 or 8 weeks of healing with a 5-mm trephine bur and immersed in 10% buffered formalin to be processed for histology. Results: A statistically insignificant correlation was detected between RFA values and mineralized bone-implant contact percentage (P ≤ .5502) using the Friedman and Spearman tests. Conclusion: RFA should reflect the bone anchorage of the implant; however, the relationship between bone structure and RFA is not fully understood. [ABSTRACT FROM AUTHOR]

The aim of this histologic and histomorphometric study was to evaluate the periimplant bone formation around one-stage surface-modified implants that were retrieved after a healing period of 4 weeks in humans. Three patients with mandibular partial edentulism participated in the study. An implant was inserted in the posterior mandible of each patient. All implants were retrieved after a 4-week healing period. Before retrieval, all the implants were clinically osseointegrated and immobile. Around all implants, mature compact preexisting bone, lined by newly formed strongly stained bone, was found. The bone-implant contact percentages were 52.0% ± 2.5%, 61.0% ± 2.9%, and 42.0% ± 6.9%, respectively, in the three included patients. These high bone-implant contact percentages observed in an early phase of healing are probably related to the microporous structure of both surfaces and their high hydrophilicity. [ABSTRACT FROM AUTHOR]

Purpose: A high clinical and radiographic level of osseointegration has been reported for early and immediately loaded (IL) implants. The aim of this study was to analyze, histologically and histomorphometrically, the bone-titanium interface of IL and submerged titanium implants that were retrieved at 4 and 8 weeks after placement. Materials and Methods: Four patients underwent rehabilitation of the posterior mandible with fixed prostheses, and an additional implant was inserted distally in the mandible. In two patients, the additional implants were put into nonfunctional immediate loading with a fixed provisional prosthesis on the same day of the implant surgery, whereas in the other two patients, the implants were left submerged. The implant stability quotients at implant insertion were 70 and 67 for the submerged implants and 69 and 77 for the IL implants. Before retrieval, the IL implants were clinically osseointegrated and were not mobile. After 4 and 8 weeks, the four implants (two IL and two submerged) were retrieved with a 5-mm trephine and processed for histologic examination. Results: After 4 weeks, the IL implant showed a bone-implant contact percentage (BIC) of 65.6%, while the BIC for the submerged implant was 54.7%. After 8 weeks, the BIC was 76.2% for the IL implant, while for the submerged implant it was 62.3%. Conclusions: Very high BICs were present after 4 and 8 weeks around both submerged and IL implants, with the latter showing a higher quantity of bone. IL did not impede bone formation in the early healing periods. [ABSTRACT FROM AUTHOR]

Human biopsy of immediately loaded implants is the most definitive means to determine the occurrence of osseointegration. This case report discusses the histologic and histomorphometric analysis of the bone-titanium interface in immediately restored implants with and without occlusal contact, retrieved after a healing period of 5 weeks. The two implants had been inserted in the posterior mandible; both were freestanding. One implant had been put into functional loading (in occlusal contact) with a fixed provisional prosthesis on the day of implant surgery (implant A), whereas the other implant was restored without occlusal contact (implant B). Both implants were retrieved with a 5-mm trephine after 5 weeks. Before retrieval, both implants appeared to be clinically osseointegrated, and no mobility was present. Both implants were surrounded by newly formed bone lamellae. In both implants about 0.5 to 1 mm of pre-existing and newly formed bone was found coronal to the implant shoulder, with no resorption of the pre-existing coronal bone. The bone-implant contact percentage in implant A was 51.2% ± 4.5%, whereas in implant B it was 55.1% ± 2.3%. Within the limitations of this study, the histologic findings indicated that no differences were found in the histologic response around immediately restored implants with and without occlusal contact. [ABSTRACT FROM AUTHOR]

Concerns have been raised about the degradation of hydroxyapatite (HA) coatings on dental implants over time. It has been speculated that the resorption of HA could produce a space between implant and bone, resulting in mechanical instability and implant failure. A screw-shaped HA-coated implant was retrieved after the abutment had fractured after a loading period of 15 years, and was evaluated histologically. At the interface with the implant, compact mature bone, with small marrow spaces, was present. Higher magnification showed that only a few osteoblasts were present. No multinucleated giant cells were present. Bone remodeling was evidenced by the presence of many secondary osteons close to the implant surface and many reversal lines. No fibrous or granulation tissues were present at the interface. The HA coating had been completely resorbed, and just 5.1% ± 2.3% of the implant surface was covered by the HA coating. The boneimplant contact percentage was 77.6% ± 5.1%. The almost complete resorption of the HA coating did not appear to have interfered with osseointegration. The implant was osseointegrated and was still providing adequate function; thus the HA coating resorption probably had little clinical significance. [ABSTRACT FROM AUTHOR]

Purpose: This prospective clinical study evaluated the survival rate and the implant-crown success of 314 Morse taper connection implants, used for single-tooth replacement, after 1 year of functional loading. Materials and methods: Over a 4-year period (January 2003 to January 2007), 314 implants (168 maxilla, 146 mandible) were inserted in 302 patients (128 males, 174 females, aged between 23 to 79 years) in six different clinical centres. The sites included anterior (n = 118) and posterior (n = 196) teeth. To evaluate implant-crown success, the following clinical, prosthetic and radiographic parameters were assessed: modified plaque index (mPI), modified sulcus bleeding index (mBI), probing depth (PD), distance from the implant crown margin to the coronal border of the peri-implant mucosa (DIM), width of keratinised mucosa (KM), prosthesis function, and the distance between the implant shoulder and first crestal bone-implant contact (DIB). Success criteria included: absence of suppuration and mobility, PD<5.0mm, absence of prosthetic complications, absence of continuous peri-implant radiolucency, and DIB<1.5mm after 1-year of functional loading. Prosthetic restorations were all-ceramic (n = 116) and metal-ceramic (n = 198) crowns. Results: The implant survival rate was 98.4% (5 implant losses, 1 drop-out). A few prosthetic complications(0.6% implant-abutment loosening) were reported. The mean DIB was 0.887±0.308mm. Among the survived implants (308), four did not fulfil the success criteria, giving an implant-crown success of 98.7%. Conclusion: The use of Morse taper connection implants represents a successful procedure for singletooth replacement, in the anterior and posterior areas of both arches. The high mechanical stability may reduce prosthetic complications. [ABSTRACT FROM AUTHOR]

Purpose: To compare clinically and histologically an allogeneic bone matrix to autogenous bone chips in the vertical ridge augmentation technique using titanium-reinforced e-PTFE membranes. Materials and Methods: The study protocol was designed to include patients with bilateral posterior mandibular partial edentulism. Patients were treated with a split-mouth design approach: each side was randomly assigned to the test group (titanium-reinforced e-PTFE membrane and allogeneic bone matrix) or to the control group (titanium-reinforced e-PTFE membrane and autogenous bone chips). Different clinical parameters including the amount of vertically regenerated bone (DSB) and biologic complications were recorded. Histomorphometric analysis and the bone-implant contact percentage were performed. Results: Five female patients were enrolled in the study. Ten edentulous sites were vertically augmented and 25 implants were inserted (13 test group, 12 control group) with a staged approach. In the test group no membrane was exposed. The mean bone regeneration was 4.70 mm (SD 0.48 mm). All 13 implants appeared clinically stable. In the control group, 1 membrane was exposed after 2 months. The mean crestal bone regeneration was 4.10 mm (SD 0.88 mm). All 12 implants were stable at the abutment connection. Nine biopsy specimens from the regenerated areas were evaluated. Vertical bone regeneration was evident in both groups since all the samples demonstrated trabecular bone with different degrees of maturation and mineralization in the regenerated area. Conclusion: Within the limits of this study based on 5 patients, it appears that the behavior of the allogeneic bone matrix is similar to that of autogenous bone chips when used for vertical ridge augmentation by means of guided bone regeneration techniques. Both grafts demonstrated analogous histologic characteristics. Nevertheless, long-term clinical studies are needed to confirm these preliminary results. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to determine the clinical and histologic results of a porous synthetic hydroxyapatite (HA) compared with bovine-derived HA used in maxillary sinus augmentation. Materials and Methods: A total of 100 titanium implants were placed in 40 patients. Patients in need of maxillary sinus augmentation were divided into 2 groups. Group 1 received bovine-derived HA (20 patients with 50 implants), while group 2 received a porous synthetic HA (20 patients with 50 implants). After a healing period of 6 months, second-stage surgery was carried out. In 50 cases (25 from group 1 and 25 from group 2), bone cores were harvested from grafted areas and processed for histologic examination. Results: Four implants that failed to osseointegrate were removed at the second-stage surgery (2 from a patient from group 1, and 2 from a patient from group 2). All patients were followed for at least 1 year after loading. Histologically, most of the HA particles from both groups were surrounded by newly formed bone. No statistically significant differences were found with respect to percentage of newly formed bone between the 2 groups (P = .031); however, the groups did differ significantly with respect to the percentage of residual graft material observed (P = .001). Conclusion: This study demonstrates that both bovine-derived and porous synthetic HA can be used successfully as graft materials for maxillary sinus augmentation. The clinical performance of the 2 materials was similar. [ABSTRACT FROM AUTHOR]

Direct laser metal forming (DLMF) is a procedure in which a high-power laser beam is directed on a metal powder bed and programmed to fuse particles according to a computer-aided design file, thus generating a thin metal layer. With DLMF, it is now possible to fabricate dental implants with a superficial porous surface. The aim of the present study was to evaluate the peri-implant soft tissues around human-retrieved DLMF dental implants. Collagen fibers, in the form of bundles, were oriented perpendicularly to a distance of 100 μm from the surface, where they became parallel, running in several directions. In some portions, only a few collagen fiber bundles appeared to be oriented perpendicularly or obliquely to the plane of the section. Collagen fibers appeared to form a dense chaotic three-dimensional network running in different, more or less parallel directions to the surface. Under scanning electron microscopy, an intimate contact of the fibrous matrix with the implant surface was evident, and some collagen bundles could be seen to bind directly to the metal surface. By changing the surface microtexture, it was possible to change the response of the peri-implant soft tissues. [ABSTRACT FROM AUTHOR]