Search

Objectives: This retrospective study compared the outcomes of implants placed in alveolar ridge preservation (ARP) treated sites with those in spontaneously healed (SH) sites. Materials and Methods: The study included patients presenting with one implant placed in an ARP‐treated socket and one in an SH site. The primary outcome was the comparison of Marginal Bone Level Changes (MBLC). Statistical analysis was performed to identify factors influencing MBLC, including age, gender, smoking, parafunctional habits, and prosthetic emergence angle. Results: Of these, 28 patients (23 females, 82.1%) were included in this analysis. Sockets in the SH group were classified as type I, whereas type II sockets were more common in the ARP group. The SH group exhibited significantly higher MBLC than the ARP group (p = 0.032), with values, respectively, of 1.00 [0.25; 1.62] and 0.40 [0.00; 1.00] mm. Among all evaluated parameters, the performance of ARP was the only factor significantly affecting MBLC (β = −0.72, SE: 0.32, p = 0.026). Age, gender, smoking, parafunctional habits, and prosthetic emergence angle did not significantly affect MBLC. Conclusions: The study shows the potential role of ARP in maintaining stable marginal bone levels around implants. In our sample, ARP significantly reduced MBLC compared with spontaneous healing, highlighting its possible impact in clinical practice for better peri‐implant bone stability. [ABSTRACT FROM AUTHOR]

Objectives: Alveolar ridge preservation (ARP) is a procedure with the aim to reduce bone resorption that occurs after tooth extraction, facilitating the following implant placement. The aim of this cross‐sectional study was to evaluate the prevalence of mucositis and peri‐implantitis around implants inserted in sites treated with ARP and to investigate possible risk factors. Materials and methods: Patients who received at least one dental implant inserted in a grafted socket were considered eligible for this study. Patients were recalled for a follow‐up visit; medical history, clinical and demographic data were collected. Univariate logistic regression analyses have been performed for both implant‐level and patient‐level variables. Indeed, moderation analysis was used to investigate the indirect relationship between age and marginal bone level. Results: Fifty‐one patients who received 61 implants were enrolled in this cross‐sectional study. Thirty‐three implants were classified as "healthy" (54.1%), 23 implants showed signs of peri‐implant mucositis (37.7%), and 5 implants were diagnosed with peri‐implantitis (8.2%). Data analyzed at the patient level showed that 49% of the patients were healthy, 45.1% of the patients had mucositis and 5.9% of the patients were affected by peri‐implantitis. Mandibular sites and type III grafted sockets showed a significant association with peri‐implantitis; in addition, a history of periodontitis and an increase in age showed higher risks of developing mucositis or peri‐implantitis. Conclusions: Implants inserted in grafted sockets showed favorable rates of healthy implants in the long term. Clinical relevance: The ridge preservation procedures do not seem to increase the risk of developing mucositis or peri‐implantitis. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the present human observational study is to provide morphologic and morphometric analysis of peri‐implant connective tissue next to abutments with divergent or convergent macro‐geometry and different surface micro‐characteristics. Materials and Methods: Thirty patients were rehabilitated with single implants in the posterior area and one out of three different healing abutments with a one‐stage technique: machined divergent abutment (DIV‐MAC), machined convergent abutment (CONV‐MAC) or convergent abutment with ultrathin threaded surface (CONV‐UTM). At 3 months postimplant insertion, peri‐implant soft tissue was harvested; the following outcomes were investigated: histomorphometry (vertical width of connective and epithelial components) as detected by histology and polarized light; and connective tissue vertical width and 3D organization as detected by synchrotron‐based high‐resolution phase‐contrast‐based tomography (PhC‐μCT). Results: Significant differences in connective tissue vertical dimension (aJE‐AM) were found between DIV‐MAC and both CONV‐MAC and CONV‐UTM, both by histology and PhC‐μCT, with significantly higher values for the last two groups. Moreover, 2D histological analysis did not find significant differences in the junctional epithelium vertical dimension (PM‐aJE). Importantly, PhC‐μCT analysis revealed, at 3D level, significant greater amount and density of collagen bundles for CONV‐UTM compared with the other two groups. Conclusions: Convergent abutment profiles, regardless of their surface micro‐geometry, seem to favor axial development of peri‐implant connective tissue. Moreover, ultrathin threaded surfaces seem associated with denser and greater connective tissue organization, which might improve peri‐implant soft tissue seal. [ABSTRACT FROM AUTHOR]

Objective: To evaluate whether abutment surface and surface bio‐activation have an effect on soft tissue morphogenesis. Materials and Methods: 36 patients (36 implants) were included. Abutments were randomly divided into 4 groups (n = 9): Smooth Surface—MAChined (MAC), Ultrathin Threaded Microsurface (UTM), MAC Plasma of Argon activated (Plasma‐MAC), and UTM Plasma of Argon activated (Plasma‐UTM). After 2 months of healing, soft tissue samples were collected and prepared for histological analysis. The margin of the peri‐implant mucosa (PM), the apical extension of the barrier epithelium (aJE), and the apical location of the abutment (AM) were identified. Significances of differences among groups were tested by means of the Kruskal–Wallis test and between pairs of results by means of the Mann–Whitney test. Results: The mean (SD) vertical dimension of the mucosa was 2.5mm (1.0), including a connective tissue portion (CTP) of 0.8mm (0.8) in the MAC group; 3.6mm (0.2) with a CTP of 1.6mm (0.4) in the Plasma‐MAC group; 3.2mm (1.0), with a CPT of 0.5mm (0.6) in the UTM; and 3.3mm (0.8), with a CPT of 0.9mm (0.7) in the Plasma‐UTM group. Statistically significant differences were observed in the aJE‐AM height and PM‐aJE profile among the four experimental groups (p =.042 and p =.039, respectively). The Mann–Whitney test indicated differences between the Plasma‐abutments and the untreated abutments both for PM‐AM (p =.025) and AjE‐AM (p =.021). The differences appeared more evident when the preoperative soft tissue thickness was ≤2mm. Conclusions: Within its limits, the study demonstrated a favorable effect of the plasma treatment on the connective tissue portion tissues. Plasma‐MAC group highlighted the best performance. This behavior appeared strictly correlated with the soft tissue thickness. [ABSTRACT FROM AUTHOR]

Background: Lateral maxillary sinus augmentation (MSA) is a predictable bone regeneration technique in case of atrophy of the posterior‐upper maxilla. Aimed at obtaining quantity and quality of bone suitable for receiving osseointegrated implants, its success is largely due to the skill of the surgeon, but also to the characteristics of the biomaterial used. Methods: Twenty‐four patients needing MSA were included in the study. The patients were randomly allocated to three different groups: anorganic bovine bone mineral as control, tricalcium phosphate with or without hyaluronic acid (HA) as test groups. Nine months after MSA, bone biopsies were harvested for the histomorphometric analysis. Secondary outcomes were mean bone gain, intraoperative and postoperative complications, implant insertion torque, implant failure, and patient‐reported outcome measures. Results: Although the percentage of new bone was not statistically different between the three groups (P =.191), the percentages of residual biomaterial was significantly higher (P <.000) and nonmineralized tissue significantly lower (P <.000) in the control than in the test groups. Test groups did not differ significantly from each other for all histomorphometric parameters. The implant insertion torque was significantly higher in the control group (P <.0005). The rest of the secondary outcomes were not significantly different between the groups. Conclusion: MSA is a safe and predictable procedure in terms of histological, clinical, and PROAMs, regardless of the biomaterial used. The addition of HA did not influence the outcomes. [ABSTRACT FROM AUTHOR]

Purpose: To compare clinical and radiographic outcomes of <7 mm short (SH) implants inserted in native bone vs longer (ST) implants placed in vertically augmented partially edentulous posterior jaws. A further aim was to evaluate if the residual bone dimension plays a role in the outcomes of SH and extra‐SH implants. Materials and Methods: This review was registered with PROSPERO. An electronic literature search was performed on PubMed, Scopus and Web of Science. Randomized controlled trials (RCTs) with at least 1‐year follow‐up, comparing fixed prostheses supported by SH vs ST implants in augmented sites were included. Marginal bone level (MBL) changes, implant survival rate, and complications were evaluated through a meta‐analysis. Subgroup analysis was performed dividing the SH implants according to length at each follow‐up (1‐, 3‐, 5‐year of function). Results: Twenty‐five articles fulfilled the inclusion criteria, featuring a total of 650 SH implants placed in 415 patients and 685 ST implants placed in 403 patients. There was a trend for a significantly lower MBL associated with SH implants respect to ST implants at each follow‐up, whilst there was no evidence of a difference in failure rates between SH and ST implants, for any SH length considered and at any follow‐up. There was evidence for a lower incidence of complications in favor of SH implants at both 1‐year (P <.0001) and 3‐year follow‐up (P =.01), while at 5‐year follow‐up there was no evidence of a difference between SH and ST groups (P =.30). Conclusion: SH implants supporting partial fixed rehabilitations represent a valuable alternative to augmentation procedures in the medium term. While the performance of implants at least 5‐mm long is well documented, more studies with at least 5‐year follow‐up are needed to confirm the promising outcomes observed with <5 mm‐long fixtures. [ABSTRACT FROM AUTHOR]

Purpose: To compare the difference in alveolar bone resorption around implants after immediate placement in a bacterial induced experimental periimplantitis murine model. The various conditions that were examined were: Effect of implant surface characteristics and the onset of the induced infection. Materials and Methods: Screw‐shaped titanium implants, smooth‐surface or sand‐blasted large‐grit acid‐etched (SLA) coated, were inserted immediately after extraction of the first upper left molar, in 90 5‐6‐week‐old BALB/c mice. The mice were infected with Porphyromonas gingivalis and Fusobacterium nucleatum 21 (early infection) or 42 days (delayed infection) after implantation. Six weeks post infection, bone volume around inserted implants was measured using micro‐CT, and was compared to alveolar bone level around teeth. Histological analysis was also performed. Results: The level of bone loss was significantly higher around the implants compared to the teeth, for smooth surface implants the bone loss was higher than of the SLA surface in both control and infected groups with no statistical significance. The survival rate of the implants in immediate infection was 75% compared of the 100% survival of the delayed infection and control mice. There is no significant difference between the early and the delayed infection in alveolar bone loss level around the implants. Conclusions: This model can assist in studying the differences in alveolar bone resorption in different implants and their effect on the development of the disease. [ABSTRACT FROM AUTHOR]

Objectives. To evaluate the performances of six different bone substitute materials used as graft in maxillary sinus augmentation by means of histological and histomorphometric analysis of bone biopsies retrieved from human subjects after a 6-month healing period. Materials and Methods. Six consecutive patients (3 males, 3 females, aged 50-72 years), healthy, nonsmokers, and with good oral hygiene, presenting edentulous posterior maxilla with a residual bone crest measuring ≤ 4 mm in vertical height and 3 to 5 mm in horizontal thickness at radiographic examination, were selected to receive sinus augmentation and delayed implant placement. Under randomized conditions, sinus augmentation procedures were carried out using mineralized solvent-dehydrated bone allograft (MCBA), freeze-dried mineralized bone allograft (FDBA), anorganic bovine bone (ABB), equine-derived bone (EB), synthetic micro-macroporous biphasic calcium-phosphate block consisting of 70% beta-tricalcium phosphate and 30% hydroxyapatite (HA-β-TCP 30/70), or bioapatite-collagen (BC). After 6 months, bone core biopsies were retrieved and 13 implants were placed. Bone samples were processed for histological and histomorphometric analysis. CT scans were taken before and after surgery. After 4 months of healing, patients were restored with a provisional fixed acrylic resin prosthesis, as well as after further 2-4 months with a definitive cemented zirconia or porcelain-fused-to-metal crowns. Results. There were no postoperative complications or implant failures. The histological examination showed that all biomaterials were in close contact with newly formed bone, surrounding the graft granules with a bridge-like network. No signs of acute inflammation were observed. The histomorphometry revealed 20.1% newly formed bone for MCBA, 32.1% for FDBA, 16.1% for ABB, 22.8% for EB, 20.3% for HA-β-TCP 30/70, and 21.4% for BC. Conclusions. Within the limitations of the present investigation, all the six tested biomaterials showed good biocompatibility and osteoconductive properties when used in sinus augmentation procedures, although the FDBA seemed to have a better histomorphometric result in terms of newly formed bone and residual graft material. This trial is registered with ClinicalTrials.gov Identifier (Registration Number): NCT03496688. [ABSTRACT FROM AUTHOR]

Abstract: Background: Recently, a torque‐measuring micromotor has been shown to provide a reliable, quantitative intraoperative evaluation of bone density and implant primary stability. This may be particularly useful for determining bone quality of residual bone and consequently the most appropriate site preparation in the posterior maxilla, where bone often is of low density and quality. Purpose: This work aimed to assess the medium‐term success of implants placed during 1‐stage sinus augmentations using an undersized drilling protocol. In case of low bone density, the relationship between residual bone height (RBH) and primary stability was also investigated. Materials and Methods: Clinical records of patients who underwent sinus augmentation and concomitant implant placement following a 12.5% undersized drilling protocol were retrospectively analyzed. In all patients, bone density measured intraoperatively was ≤ 0.45 g/cm3. A minimum of 60 months of follow‐up was required for inclusion. Results: Records of 106 patients who received 253 implants were reviewed. No significant difference in the implant success rate was found for patients who had less than 4 mm of RBH and those who had more. Conclusions: Underpreparation of the implant‐placement sites enabled achievement of successful implant‐supported rehabilitation of the posterior maxilla even when both RBH and bone density were low. [ABSTRACT FROM AUTHOR]

Background. The “root membrane” (RM) is a technique that has become popular among implantologists for placement of immediate implants in the anterior maxilla. Purpose. To present histologic evidence of an immediate implant placed in the human anterior maxilla, according to the RM technique, and retrieved after five years. Methods. A fixture, along with the surrounding tissues, was retrieved from the anterior maxilla of a 68-year-old patient, who had been treated five years earlier with immediate implant placement and RM technique. The specimen was processed for histologic/histomorphometric evaluation. Results. The buccal bone plate was maintained without any resorption; a healthy periodontal ligament was evidenced. The implant showed osseointegration, with a high percentage of bone-to-implant contact (BIC = 76.2%). With regard to the space between the RM and the implant, the apical and medial thirds were filled with compact, mature bone; the coronal third was colonized by noninfiltrated connective tissue. Conclusions. The RM technique appears to be effective in preventing bone resorption of the buccal bone plate of the human anterior maxilla, five years after the placement of an immediate implant. [ABSTRACT FROM AUTHOR]

Background. Direct metal laser sintering (DMLS) is an additive manufacturing technique that allows the fabrication of dental implants layer by layer through the laser fusion of titanium microparticles. The surface of DMLS implants is characterized by a high open porosity with interconnected pores of different sizes; therefore, it has the potential to enhance and accelerate bone healing. To date, however, there are no histologic/histomorphometric studies in the literature evaluating the interface between bone and DMLS implants in the long-term. Purpose. To evaluate the interface between bone and DMLS implants retrieved after 5 years of functional loading. Methods. Two fractured DMLS implants were retrieved from the human jaws, using a 5 mm trephine bur. Both the implants were clinically stable and functioned regularly before fracture. The specimens were processed for histologic/histomorphometric evaluation; the bone-to-implant contact (BIC%) was calculated. Results. Compact, mature lamellar bone was found over most of the DMLS implants in close contact with the implant surface; the histomorphometric evaluation showed a mean BIC% of 66.1% (±4.5%). Conclusions. The present histologic/histomorphometric study showed that DMLS implants were well integrated in bone, after 5 years of loading, with the peri-implant bone undergoing continuous remodeling at the interface. [ABSTRACT FROM AUTHOR]

Aim. To evaluate the effects of fixture design and surface on the early bone formation around immediately loaded implants inserted in the human posterior maxilla. Materials and Methods. Ten totally edentulous subjects received two transitional implants: one tapered implant with knife-edge threads/nanostructured calcium-incorporated surface (test: Anyridge®, Megagen, Gyeongbuk, South Korea) and one cylindrical implant with self-tapping threads/sandblasted surface (control: EZPlus®, Megagen). The implants were placed according to a split-mouth design and immediately loaded to support an interim complete denture; after 8 weeks, they were removed for histologic/histomorphometric analysis. The bone-to-implant contact (BIC%) and the bone density (BD%) were calculated. The Wilcoxon test was used to evaluate the differences. Results. With test implants, a mean BIC% and BD% of 35.9 (±9.1) and 31.8 (±7.5) were found. With control implants, a mean BIC% and BD% of 29.9 (±7.6) and 32.5 (±3.9) were found. The mean BIC% was higher with test implants, but this difference was not significant (p=0.16). Similar BD% were found in the two groups (p=0.9). Conclusions. In the posterior maxilla, under immediate loading conditions, implants with a knife-edge thread design/nanostructured calcium-incorporated surface seem to increase the peri-implant endosseous healing properties, when compared to implants with self-tapping thread design/sandblasted surface. [ABSTRACT FROM AUTHOR]

Objective This study evaluated the effect of cigarette smoking on the percentage of early bone-to-implant contact ( BIC%), the bone density in the threaded area ( BA%) as well as the bone density outside the threaded area ( BD%) around micro-implants with sandblasted acid-etched surface retrieved from human jaws. Material and methods Twenty-two subjects (mean age 55.4 ± 4.5 years) were divided in two groups: smokers ( n = 11 subjects) and never-smokers ( n = 11 subjects). Each subject received one micro-implant during conventional mandible or maxilla implant surgery. After 8 weeks, the micro-implants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results Two micro-implants placed in smokers showed no osseointegration. Early stages of maturation of the newly formed bone were present, mainly in the never-smokers. Marginal bone loss, gap, and fibrous tissue were present around some implants retrieved from smokers. Histometric evaluation indicated that the mean BIC% ranged between 25.9 ± 9.1 and 39.8 ± 14.2 for smokers and non-smokers, respectively ( P = 0.02). Smokers presented 28.6 ± 10.1 of BA% while never-smokers showed 46.4 ± 18.8 ( P = 0.04). The mean of BD% ranged between 19.1 ± 7.6 and 28.5 ± 18.8 for smokers and never-smokers, respectively ( P = 0.21). Conclusion Cigarette smoking has a detrimental effect on early bone tissue response around sandblasted acid-etched implant surface topographies. [ABSTRACT FROM AUTHOR]

Objective In the present study, a new healing cap that could generate a pulsed electromagnetic field (PEMF) around titanium implants to stimulate peri-implant osteogenesis was tested in the rabbit model. Materials and methods A total of 22 implants were inserted in the proximal tibial metaphysis of 22 rabbits. A healing cap containing the active device was inserted in half of the implants (11 test implants); an 'empty' healing cap was inserted in the other ones (11 control implants). The animals were euthanized after 2 and 4 weeks, and the samples were processed for micro-computed tomography and histology. The peri-implant volume was divided into coronal (where the PEMF was the strongest) and apical regions. Results Most of the effects of the tested device were confined to the coronal region. Two weeks post-implantation, test implants showed a significant 56% higher trabecular bone fraction (BV/TV), associated with enhanced trabecular number (Tb.N, +37%) and connectivity density (Conn.D, +73%) as compared to the control group; at 4 weeks, the PEMF induced a 69% increase in BV/TV and 34% increase of Tb.N. There was no difference in the trabecular thickness (Tb.Th) at either time point. Furthermore, we observed a 48% higher bone-to-implant contact (BIC) in the test implants vs. controls after 2 weeks; this increase tended to remain stable until the fourth week. Mature trabecular and woven bone were observed in direct contact with the implant surface with no gaps or connective tissue at the bone-implant interface. Conclusions These results indicate that the PEMF device stimulated early bone formation around dental implants resulting in higher peri-implant BIC and bone mass already after 2 weeks which suggests an acceleration of the osseointegration process by more than three times. [ABSTRACT FROM AUTHOR]

Objectives Osteocytes have emerged as key regulators of skeletal and mineral homeostasis. The number of these cells could be influenced by the presence of osteoporosis and osteopenia. Hence, the aim this study was to evaluate the osteocyte density in patients with osteopenia, and in patients with osteoporosis treated with bisphosphonates. Materials and methods Thirty-nine patients were selected for this study and divided into three groups: (A) nine healthy patients (control), (B) 15 patients with osteopenia, and (C) 15 patients with osteoporosis. During the surgical insertion of dental implants in the lower jaw, bone samples were retrieved and processed for histological analysis of osteocyte density, measured as number of osteocytes/bone tissue area (μm2). Results Patients with osteopenia showed statistically higher values of osteocyte density than patients with osteoporosis ( P < 0.05) No significant differences were detected between osteopenia and osteoporosis subjects vs. healthy patients ( P > 0.05). Conclusions Bone metabolism diseases (osteoporosis and osteopenia) do not seem to influence the osteocyte density; this could be due to the administration of bisphosphonates in patients with osteoporosis. This information could play a fundamental role in the diagnosis and treatment of patients in a postmenopausal stage. [ABSTRACT FROM AUTHOR]

Objective To study osseointegration of implants with surface modifications by the use of fluoroboric acid and/or H2O2 installed in conventional sites or sites with circumferential marginal defects. Material and methods Four implants with different surfaces were used. One basic surface (ZirTi®) was sandblasted with zirconium microspheres and acid etched additionally with hydrofluoric acid. A second surface was treated with fluoroboric acid instead of hydrofluoric acid. The remainder of the other two surfaces was additionally treated with H2O2. The edentulous mandibles of 6 foxhound dogs were used to randomly install 8.5-mm-long implants with the different surfaces and to study the histological healing after 1 and 3 months. To study osteoconductivity, additional four recipient sites were prepared with the coronal region being widened so that a 4 mm deep and 0.85 mm wide marginal defect resulted after the placement of the four implants with different surfaces. No filler material or membranes were used, and a fully submerged healing was allowed for 3 months. Results At the conventional sites, new bone formation ranged between 68.5% and 74.9% after 1 month. After 3 months, bone-to-implant contact ranged from 72.6% at the ZirTi® surface to 84.1% at the fluoroboric acid-treated implants, the difference being statistically significant. At the sites with marginal defects, bone formation ranged from 0.77 mm at the surface treated with fluoroboric acid and H2O2, to 1.93 mm at the surface treated with fluoroboric acid alone. Conclusions Fluoroboric acid treatment alone of titanium implant surfaces resulted in improved osseointegration and osteoconductivity after 3 months. [ABSTRACT FROM AUTHOR]

The aim of this case report was to describe the surgical sequence of crown lengthening to apically reposition the dentogingival complex, in addition to an esthetic restorative procedure. Many different causes can be responsible for short clinical crown. In these cases, the correct execution of a restorative or prosthetic rehabilitation requires an increasing of the crown length. According to the 2003 American Academy of Periodontology (Practice Profile Survey), crown lengthening is the most habitual surgical periodontal treatment. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to perform a 2 months clinical and histological comparison of autologous bone, porcine bone, and a 50 : 50 mixture in maxillary sinus augmentation procedures. Materials and methods A total of 10 consecutive patients, undergoing two-stage sinus augmentation procedures using 100% autologous bone (Group A), 100% porcine bone (Group B), and a 50 : 50 mixture of autologous and porcine bone (Group C) were included in this study. After a 2-month healing period, at the time of implant insertion, clinical evaluation was performed and bone core biopsies were harvested and processed for histological analysis. Results The postoperative healing was uneventful regardless of the materials used for the sinus augmentation procedures. The histomorphometrical analysis revealed comparable percentages of newly formed bone, marrow spaces, and residual grafted material in the three groups. Conclusion The clinical and histological results of this study indicated that porcine bone alone or in combination with autologous bone are biocompatible and osteoconductive materials and can be successfully used in sinus augmentation procedures. [ABSTRACT FROM AUTHOR]

Purpose/Aim Evaluate differences in bone remodeling, soft tissue reactions and biological width formation around immediate implants placed at different level in relation to the crestal bone in beagle dogs. Material and methods The mandibular second, third and fourth premolars of six beagle dogs were extracted, and three implants were placed in the right side of each dog. Healing abutments were adjusted ( n = 18). After 4 weeks, the procedure was repeated on the left side of the mandible ( n = 18). Randomly, three implants were placed at crestal level (control group), and three implants were placed 2 mm subcrestally (test group) in relation to the crestal bone in each animal. The dogs were sacrificed after 8 weeks from the first surgical procedure, and biopsies were obtained. Samples were processed for ground sectioning. Histometric analysis was carried out to compare buccal and lingual bone resorption, soft tissue behavior and biological width formation in both groups. Results Crestal bone resorption was higher in the test group when considering the difference of 2 mms ( IS-B = 2.05 ± 0.36 mm, control; 1.75 (+2) ± 0.38 mm, test). However, the dimensions of the biological width were similar for both groups ( PM-C = 3.34 ± 0.53 mm, control; 3.13 ± 0.55 mm, test). Conclusions The alterations that occurred in the peri-implant soft tissues may be related to the hard tissue remodeling, showing similar quantitative findings in the biological width formation in both groups. Even though the subcrestal placement might reduce the distance from the implant shoulder to the first bone-to-implant contact and reestablish the biological width dimension in a most coronal position, it might not have any effect on minimizing the marginal bone loss. [ABSTRACT FROM AUTHOR]

Objective The aim of this study was to evaluate and compare the histological and histomorphometric features of two different procedures carried out in extraction socket grafting; namely, the flapped and flapless technique. Materials and methods Patients considered eligible for the study were randomized to receive tooth extraction and ridge preservation with the porcine bone and collagen membrane, with a full thickness mucoperiosteal flap and primary soft tissue closure (control group), or, with a flapless procedure and a secondary soft tissue closure (test group). After 3 months of healing, the surgical re-entry procedure was performed and implants were inserted in the test as well as in the control sites. Bone core samples were harvested from both groups and processed to be observed under light microscopy. Outcome variables were percentages of newly formed bone, residual graft particles and marrow spaces. Results Thirty-four patients were enrolled in the study. All of the scheduled implants were placed. Histological and histomorphometrical analyses did not report significant differences between the two groups (with P-values ranging from 0.690 to 0.917). The mean percentages of newly formed bone, soft tissues and residual grafted particles were 22.5 and 22.5%, 59.3 and 59.4%, and 18.6 and 18.2% respectively for flap and flapless approach. Conclusion No histological and histomorphometrical differences were observed when comparing the flap and the flapless technique for tooth extraction and socket grafting procedures. [ABSTRACT FROM AUTHOR]

Background By mixing hydroxyapatite ( HA) and tricalcium phosphate ( TCP), biphasic calcium phosphate ceramics can be obtained, and by varying their ratio it is possible to tailor the characteristics of the biomaterial. Purpose The aim of the present human study was to evaluate the histological and radiographical aspects of bone formation in maxillary sinus augmentation using a 30/70 HA-beta- TCP with a reticular structure. Materials and Methods A total of 12 patients, undergoing two-stage sinus augmentation procedure using HA-beta- TCP at a ratio of 30/70, were included in the present study. After a 6-month healing period, during implant insertion, radiographical analysis was performed, and then the bone core biopsies were harvested and processed for histology. Results At radiographic evaluation, the bone gain was on average 6.85 ± 0.60 mm. HA-beta- TCP 30/70 appeared to be lined by newly formed bone, with no gaps at the interface. The histomorphometric analysis revealed 26 ± 2% of residual grafted biomaterial, 29 ± 3% of newly formed bone, and 45 ± 2% of marrow spaces. Conclusions The present results indicate histologically the high biocompatibility and osteoconductivity of HA-beta- TCP 30/70, and clinically its successful use for sinus augmentation procedures. [ABSTRACT FROM AUTHOR]

This report documents the clinical, radiographic, and histologic outcome of a custom-made computer-aided-design/computer-aided-manufactured (CAD/CAM) scaffold used for the alveolar ridge augmentation of a severely atrophic anterior mandible. Computed tomographic (CT) images of an atrophic anterior mandible were acquired and modified into a 3-dimensional (3D) reconstruction model; this was transferred to a CAD program, where a custom-made scaffold was designed. CAM software generated a set of tool-paths for the manufacture of the scaffold on a computer-numerical-control milling machine into the exact shape of the 3D design. A custom-made scaffold was milled from a synthetic micromacroporous biphasic calcium phosphate (BCP) block. The scaffold closely matched the shape of the defect: this helped to reduce the time for the surgery and contributed to good healing. One year later, newly formed and well-integrated bone was clinically available, and two implants (AnyRidge, MegaGen, Gyeongbuk, South Korea) were placed. The histologic samples retrieved from the implant sites revealed compact mature bone undergoing remodelling, marrow spaces, and newly formed trabecular bone surrounded by residual BCP particles. This study demonstrates that custom-made scaffolds can be fabricated by combining CT scans and CAD/CAM techniques. Further studies on a larger sample of patients are needed to confirm these results. [ABSTRACT FROM AUTHOR]

Objectives The aim of this study was to evaluate the effect of lateral static load in immediately restored implants in the canine mandible. Material and methods In 7 mongrel dogs, all premolars and the first molars were extracted bilaterally in the mandible. Two months after the extractions, 6 implants with sandblasted acid-etched surfaces were placed in each animal, 3 on each side. Randomly, two implants per side were immediately restored with an orthodontic expansion device that promoted lateral excessive static load (test group) or load (control) while the third implant of each side, remained submerged (unloaded group). These loaded devices were cleaned daily with chlorhexidine 0.12%, during the 4 months of study, when the animals were sacrificed and biopsies removed for histometric study. Intra-oral periapicals were made using positioners at the beginning and at the end of the study. Results Five implants from test group were lost in 3 dogs. Radiographically, there was a marginal bone loss of 3.68 ± 0.74 mm for the test group, 1.63 ± 0.2 mm for the control group and 0.45 ± 0.5 mm for the unloaded group. Histometrically, the percentage of bone-to-implant contact ( BIC%) was 35.52 ± 7.32%, for the test group, 63.16 ± 5.16% for the control group and 42.33 ± 2.14% for the unloaded group. Conclusion In conclusion, the excessive lateral static load negatively affected the behavior of peri-implant bone around immediate restored implants. [ABSTRACT FROM AUTHOR]

Objective To study the sequential healing at bicortically installed implants with surface modifications by the use of fluoroboric acid and/or H2O2. Material and methods Twenty-eight albino New Zealand rabbits were used. Two recipient sites were prepared in the tibiae bilaterally, one in the metaphysis and the second in the diaphysis regions. Four implants with different surface characteristics were randomly installed with bicortical stabilization: (i) sandblasted and acid-etched; (ii) same surface as i, but with a substitution of the hydrofluoric acid with fluoroboric acid; (iii) same surface as i, additionally treated with H2O2; and (iv) same surface modified as ii, additionally treated with H2O2. The animals were killed after 5, 8, 15, and 30 days. Ground sections were prepared for histological analyses. Results No statistically significant differences in osseointegration were found among various surfaces at any of the healing periods. A higher degree of osseointegration was observed at the implants placed in the metaphysis compared to those placed in the diaphysis, especially during early healing. A higher degree of osseointegration was found at sites with proximity to compact (cortical) bone when compared to the middle portion of the implants, especially in the diaphysis region. Conclusions Surfaces modified with different acids or H2O2 resulted in similar osseointegration compared to a standard sandblasted and acid-etched surface. The portion of the bicortically installed implants in close contact with the cortical compartment presented a higher percentage of osseointegration compared with the region in contact with the bone marrow compartment. [ABSTRACT FROM AUTHOR]

Purpose The present study aimed to assess clinical and biological performances of several bone substitute biomaterials ( BSBs). Materials and Methods The evaluation was conducted at 6 months and after several years on 295 patients undergoing sinus augmentation with 13 different BSBs; the data belonging to previously published studies have been analyzed using innovative mathematical models to evaluate the bone regenerative index ( Br) and the structural density index ( Ds). Results After 6 months, compared to the Ds index of native bone, the regenerated bone showed a D3 bone type; while, after several years, the regenerated bone type was D2, with an evident increase in the density of the regenerated bone over time. Moreover, the values of Br were higher for combined biomaterials indicating a fewer amount of residual particles and marrow spaces, while the values of Ds were higher for anorganic bovine bone indicating a greater new bone formation and a lesser amount of marrow spaces. After 20 years, the bone regenerated using hydroxyapatite still had a D4 bone quality. Conclusions After 6 months of healing, the regenerated bone had a composite structure resembling poor D3 bone type, and covered approximately one-third of the space filled by BSBs. None of the evaluated biomaterials seemed to be ideal. [ABSTRACT FROM AUTHOR]

Purpose The purpose of the present preliminary in vitro study on bovine ribs was to validate a new intraoperative site-specific classification of bone Density Index ( IDI), obtained by an innovative computerized implant motor, by correlating these data with the data obtained by the histomorphometrical evaluation of the same samples. Materials and Methods Five segments of bovine ribs were used, and a total of 22 perforations were performed. A computerized implant motor (' Torque Measuring Motor') was used to evaluate the bone density, which was classified into four classes: ID1, ID2, ID3, and ID4. Histomorphometrical analysis of bone density, expressed as percentage of bony trabeculae over the total biopsy area, was also performed. The data of bone density obtained by the implant motor were statistically correlated with the histomorphometrical results. Results A significant positive correlation was found between the bone density measured by the implant motor and the bone density assessed by histomorphometry (r = 0.89, p < .0001). Moreover, a significant positive correlation in D1, D2, and D4, whereas a negative, not significant correlation in D3 was found. Conclusion Within the limitations of this in vitro study, the intraoperative site-specific classification of bone density, obtained with this innovative system, could be helpful for the clinician to tailor the surgical protocol to the different situations in implant dentistry. [ABSTRACT FROM AUTHOR]

Background In recent years, there has been interest on the fabrication of systems using particulates or block-based approach for bone tissue engineering ( TE) scaffolds, possessing porous interconnected structures. In fact, these particular morphologies greatly increase the surface area for more chemical and biological reactions to take place. Purpose This study was designed to demonstrate the unique capability of the synchrotron radiation x-ray microtomography (micro- CT) in offering an advanced characterization of coralline-derived (Biocoral) biomaterials placed in human maxillary defects as it allows, in a nondestructive way, a complete, precise, and high-resolution three-dimensional analysis of their microstructural parameters. Moreover, the comparison between Biocoral and other biomaterials was explored to understand the mechanism of their biological behavior as bone substitute. Materials and Methods Implant survival, bone regeneration, graft resorption, neovascularization, and morphometric parameters (including anisotropy and connectivity index of the structures) were evaluated by micro- CT in Biocoral and the other biomaterials after 6 to 7 months from implantation in human maxillary bone defects. Results After the in vivo tests, a huge amount of bone was detected in the retrieved Biocoral-based samples, coupled with a good rate of biomaterial resorption and the formation of a homogeneous and rich net of new vessels. The morphometric parameters were comparable to those obtained in the biphasic calcium phosphate-based control, with the exception of the connectivity index for which this control exhibited the most well-connected structure. This last result, together with those referred to the poor performances of the β-tricalcium phosphate block-based sample, suggests that the particular scaffold morphology may play a role in the hunt the optimal scaffold structure to be implanted. Conclusion In this limited study, implant success rate seems not strictly dependent on the biomaterial that is used, but on the scaffold morphology. Micro- CT technique was demonstrated to play a fundamental role in advanced characterization of bone TE constructs. [ABSTRACT FROM AUTHOR]

Background Differences in implant microtexture are important in conditioning the bone response around dental implants. Purpose The aim of the present study was an evaluation of the bone response in machined ( M), blasted with apatitic calcium phosphate (tricalcium phosphate/hydrossyapatite [ HA] blend) particles (resorbable blast texturing [ RBT]), and coated with HA implants. Methods A total of 48 (16 M, 16 RBT, and 16 HA) threaded screw-shaped implants were inserted into the tibia of 12 rabbits. The specimens were retrieved after 1, 2, 4, and 8 weeks and processed for histology. Results All experimental groups showed an increase of the bone-implant contact percentages through the study period. Higher and highly statistically significant differences were found in the percentages of bone observed in the concavities rather than in the convexities of the implants retrieved after 1, 2, and 4 weeks, while no significant differences were found after 8 weeks. In the different time periods, higher percentages of bone-implant contact were found in the RBT and HA-coated implants both in the concavities and in the convexities, but these differences were not statistically significant. Conclusions The newly formed bone present in the concavity of the threads was not influenced by the implant surface in the first healing period, while after 4 to 8 weeks, the percentage of bone observed in the concavities and convexities was similar. Additional histological studies are necessary to further evaluate the critical role of the concave geometry in bone differentiation and formation around dental implants. [ABSTRACT FROM AUTHOR]

Aims It has been accepted that bone damage and subsequent resorption occurs in cases of adverse interfacial bone strain. Fractured implants represents an important opportunity for evaluating the bone response to overstrain. The objective of the study was to analyze the bone morphology and morphometry around retrieved fractured implants in humans. Five fractured implants retrieved after 22.4 (± 2.8) years were used in the present study. The investigation was conducted in a transmitted brightfield and circularly polarized light Microscope. The parameters considered were the total bone area, total bone remodeling area, bone-remodeling rate (BRR), and bone transverse collagen fibers orientation (CFO). Findings For grouped samples, the BRR was 51.9% (± 10) while the transverse CFO was 13.0% (± 9.7). The interthread BRR was 58.1% (± 4.0) for level 1 and 40.4% (± 12.8) for level 2 with a significant decrease in BRR ( p = 0.019) as a function of depth along the implant length. Conclusions Both bone level and bone quality attains stability to a certain level with respect to implant neck fracture following physiologic interaction between mechanical and biological inputs. The BRR significantly decrease as function of threads depth. © 2014 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 1342-1352, 2014. [ABSTRACT FROM AUTHOR]

Background Implant stability is one of the key factors for a successful osseointegration. At present, several techniques are available to regenerate bone tissue, but it is not clear whether implants placed in grafted bone are as stable as implants in native bone over time. Purpose The aim of the present study was to compare, by means of resonance frequency analysis ( RFA), the stability of implants placed in sinus-grafted and -nongrafted sites during 12-month follow-up. Methods Twenty-five patients received a total of 38 implants. Nineteen implants were placed in maxillary native bone (group A) and 19 implants following maxillary sinus floor augmentation using anorganic bovine bone and autogenous bone (group B) in a 50:50 ratio. Group B was divided into groups B1 and B2 depending on the timing of implant insertion, that is, B1 simultaneously and B2 6 months after sinus lift. The implants were inserted according to a two-stage procedure. RFA values were collected at baseline, 6 and 12 months after implant placement. Results Between the tested groups, no statistically significant difference was found in RFA values of implants placed in sinus-grafted and -nongrafted sites after the surgery as well as at 6 and 12 months, while a significant difference was recorded in group B1 ( p = .0297) when RFA values were compared over time. Conclusions The results of the present study suggest that regenerated bone can offer good stability for dental implants. [ABSTRACT FROM AUTHOR]

Objectives The aim of the present study was to evaluate bone-to-implant contact ( BIC) and bone remodeling dynamics after immediate implant placement at different levels in relation to the crestal bone. Materials and methods The mandibular second, third, and fourth premolars of six Foxhound dogs were extracted bilaterally. Randomly, three implants were immediately placed in the hemi-arches of each dog, crestally or 2 mm subcrestally. Three dogs were allowed an 8-week submerged healing period, and the other three at 12-week submerged healing period. The animals were sacrificed at 12 weeks and samples were obtained. Biopsies were processed for ground sectioning. Histomorphometric analysis was carried out to compare BIC, bone neoformation, and bone remodeling. Results All implants osseointegrated clinically and histologically. Healing patterns examined microscopically at eight and twelve weeks for both groups (crestal and subcrestal) yielded similar qualitative bone findings. The Total BIC mean value for the crestal group 44.52% at 8 weeks and 39.50% at 12 weeks, and for the subcrestal group was 47.33% at 8 weeks and 53.85% at 12 weeks%. There was less bone resorption in the subcrestal group (test) than in crestal group (control). Conclusions Within the limitations of this study, our findings suggest that apical positioning of the top of the implant does not jeopardize bone crest and peri-implant tissue remodeling. However, less resorption of the lingual crest may be expected when implants are placed 2 mm subcrestally. Moreover, higher BIC values were found in implants placed subcrestally. [ABSTRACT FROM AUTHOR]

Bone tissue is characterized by a constant turnover in response to mechanical stimuli, and osteocytes play an essential role in bone mechanical adaptation. However, little to no information has been published regarding osteocyte density as a function of implantation time in vivo. The aim of this retrospective histological study was to evaluate the osteocyte density of the peri-implant bone in implants retrieved because of different reasons in a time period from 4 weeks to 27 years. A total of 18 samples were included in the present study. Specimens were divided into 3 groups depending on the loading history of the implants: loading between 4 weeks and 7 months (group 1); loading between 1 and 5 years (group 2); loading between 14 and 27 years (group 3). All the samples were histologically evaluated and osteocyte density was obtained using the ratio of the number of osteocytes to the bone-area (mm2). The osteocyte density values significantly increased in the Group 2 (1-5 years) compared with Group 1 (4 weeks-7 months), and significantly decreased in the Group 3 (14-27 years) compared to Group 2. No significant differences were detected between Group 1 and Group 3. The decrease in osteocyte density observed in samples that were in vivo for long periods of time under loading is possibly because of the fact that once the bone structure is well aligned and biomechanically competent, a lower number of osteocytes are necessary to keep the tissue homeostasis under loading. © 2013 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 102B: 239-243, 2014. [ABSTRACT FROM AUTHOR]

The aim of the present study is to compare the histological aspects of bone formation in atrophic posterior mandibles augmented by autologous bone block from chin area with corticocancellous bone block allograft used as inlays with the sandwich technique. Materials and Methods. Sixteen patients with bilateral partial edentulism in the posterior mandible were selected. The residual bone height, preliminarily measured by computed tomography scans, ranged between 5 and 7mm from the inferior alveolar nerve. All patients required regeneration procedure with autologous bone block from chin area (control group) versus bone block allograft Puros (Zimmer Dental, 1900 Aston Avenue, Carlsbad, CA, USA) (test group). Histological and histomorphometric samples were collected at the time of implant positioning in order to analyze the percentage of newly formed bone, the residual graft material, and marrow spaces/soft tissue. Results. No statistically significant differences between the two groups were found regarding the percentage of newly formed bone. The percentage of residual grafted material was significantly higher in the test group, whilst the percentage of marrow spaces was higher in control group. Conclusions. In conclusion, both procedures supported good results, although the use of bone blocks allograft was less invasive and preferable than harvesting bone from the mental symphysis. [ABSTRACT FROM AUTHOR]

Background: The preservation of hard and soft tissue volume, partially lost after tooth removal, can potentially reduce the need for the more demanding augmentation procedures used in implant-supported rehabilitation. The objective of this research study is to investigate the effect of filling with xenogeneic material the postextractive sockets of two surgical procedures (flapless versus flapped). Methods: In this prospective randomized clinical survey, two types of socket preservation were performed on two groups of patients: the control, treated via full-thickness mucoperiosteal flap, and the test, via a flapless procedure. Anatomic measurements and related outcome variables at the third month were analyzed using multiway analysis of variance. Multiple comparison tests, using Tukey honestly significant difference test, and appropriate pairwise comparison tests for independent samples were carried out. Results: Sixty-four patients were treated, 32 for each of the two socket preservation procedures. Statistically significant differences were registered for the output variables -- changes in width of keratinized gingiva, changes in bucco-lingual width, and vertical bone changes at four sites--between the two socket preservation techniques, with P values of <0.001, <0.001, and 0.0105, respectively. Conclusions: A full-thickness mucoperiosteal flap gave significantly more negative results than that of the less-demanding flapless procedure, with an increased width resorption of the postextraction site. Moreover, the increased value of the keratinized gingival width attested to the positive outcome of a flapless procedure in terms of soft tissue preservation and improvement. On the other hand, the flapped technique seemed to show less vertical bone resorption on the buccal aspect than the flapless technique. [ABSTRACT FROM AUTHOR]

The aim of this study was to achieve aesthetically pleasing soft tissue contours in a severely compromised tooth in the anterior region of the maxilla. For a right-maxillary central incisor with localized advanced chronic periodontitis a tooth extraction followed by reconstructive procedures and delayed implant placement was proposed and accepted by the patient. Guided bone regeneration (GBR) technique was employed, with a biphasic calcium-phosphate (BCP) block graft placed in the extraction socket in conjunction with granules of the same material and a resorbable barrier membrane. After 6 months of healing, an implant was installed. The acrylic provisional restoration remained in situ for 3 months and then was substituted with the definitive crown. This ridge reconstruction technique enabled preserving both hard and soft tissues and counteracting vertical and horizontal bone resorption after tooth extraction and allowed for an ideal three-dimensional implant placement. Localized severe alveolar bone resorption of the anterior maxilla associated with chronic periodontal disease can be successfully treated by means of ridge reconstruction with GBR and delayed implant insertion; the placement of an early-loaded, Morse taper connection implant in the grafted site was effective to create an excellent clinical aesthetic result and to maintain it along time. [ABSTRACT FROM AUTHOR]

Several histologic studies regarding peri-implant soft tissues and biological width around dental implants have been done in animals. However, these findings in human peri-implant soft tissues are very scarce. Therefore, the aim of this case series was to compare the biological width around unloaded one- and two-piece implants retrieved fromhuman jaws. Eight partially edentulous patients received 2 test implants in the posterior mandible: one-piece (solid implants that comprise implant and abutment in one piece) and two-piece (external hexagon with a healing abutment) implants. After 4months of healing, the implants and surrounding tissue were removed for histologic analysis. The retrieved implants showed healthy peri-implant bone and exhibited early stages of maturation. Marginal bone loss, gaps, and fibrous tissuewere not present around retrieved specimens. The biologic width dimension ranged between 2.55 ± 0.16 and 3.26 ± 0.15 to one- and two-piece implants, respectively (P < 0.05). This difference was influenced by the connective tissue attachment, while sulcus depth and epithelial junction presented the same dimension for both groups (P > 0.05). Within the limits of this study, it could be shown that two-piece implants resulted in the thickening of the connective tissue attachment, resulting in the increase of the biological width, when compared to one-piece implants. [ABSTRACT FROM AUTHOR]

The present study aims to evaluate the influence of apicocoronal position and immediate and conventional loading in the percentage of bone-implant contact (BIC). Thus, 36 implants were inserted in the edentulous mandible from six dogs. Three implants were installed in each hemimandible, in different positions in relation to the ridge: Bone Level (at crestal bone level), Minus 1 (one millimeter apical to crestal bone), and Minus 2 (two millimeters apical to crestal bone). In addition, each hemimandible was submitted to a loading protocol: immediate (prosthesis installed 24 hours after implantation) or conventional (prosthesis installed 120 days after implantation). Ninety days after, animals were killed, and implant and adjacent tissues were prepared for histometric analysis. BICvalues fromimmediate loaded implantswere 58.7%, 57.7%, and51.1%, respectively, while conventional loaded implants were 61.8%, 53.8%, and 68.4%. Differences statistically significant were not observed among groups (p = 0.10, ANOVA test).These findings suggest that different apicocoronal positioning and loading protocols evaluated did not interfere in the percentage of boneimplant contact, suggesting that these procedures did not jeopardize osseointegration. [ABSTRACT FROM AUTHOR]

Purpose: The aims of the study are to introduce a new parameter to measure primary stability and to evaluate the possible correlations between this parameter and bone density, initial bone-to-implant contact (IBIC), Resonance Frequency Analysis (RFA), and peak insertion torque (IT). Material and Methods: The study was performed on three different types of fresh humid bovine bone: type I, type II, and type III. A total of 90 XiVE implants (30 per bone type) were used; implant insertion was performed with a calibrated maximum torque of 70 Ncm at predetermined 30 rpm. The IT data were recorded and exported as a curve; using a trapezoidal integration technique, the area underlying the curve was calculated: this area represents the variable torque work (VTW). Furthermore, peak IT and RFA were recorded; finally IBIC was calculated from histological specimens. Results: Spearman correlation analysis of the entire sample reveals that VTW presents a significant ( p < .01) positive correlation with bone density; a significant ( p < .05) positive correlation with IBIC, and a significant ( p < .01) positive correlation with all the other primary stability parameters. Spearman correlation analysis of the three different groups show that VTW presents a significant positive correlation with IT in all three types of bone; on the other hand, VTW shows a negative not significant correlation with RFA in bone I, a positive significant correlation in bone II, and a positive not significant correlation in bone III. Furthermore, VTW shows a negative significant correlation with IBIC in bone I and a positive significant correlation in bone II and III. Conclusions: Within the limitations of an in vitro study, the VTW seems to be a promising parameter to measure implant primary stability. [ABSTRACT FROM AUTHOR]

Background: The aim of the present study is to perform a systematic review of the literature on the use of titanium grids for implant surgery before and simultaneously with implant placement and to assess the success rate of the procedure, as well as survival and success rates of implants placed in the regenerated areas. Methods: Medline was used to identify studies in English published from 1996 to 2011. An additional hand search was performed of the relevant journals and of the bibliographies of the papers identified. Articles retrieved by two independent authors were screened using specific inclusion criteria: randomized controlled trials (RCTs), controlled clinical trials, and prospective clinical studies regarding vertical and/or horizontal regeneration of the alveolar ridge using titanium grids, in association or not with biomaterials, before and simultaneously with implant placement. Results: Six articles were selected, including a total of 79 patients, 87 titanium grids, and 141 implants. Twenty-four implants were placed simultaneously with titanium grids, and 117 implants were inserted after a period of 4 to 9 months. Titanium grids in combination with autogenous bone were used in 43 cases, 25 in combination with a mixture of autogenous bone and bone substitutes, 14 in association with bone substitutes, five using only titanium grids. The overall success rate of the regenerative procedures was 98.86%; the overall survival and success rates of implants were 100% and 93.2%, respectively. Conclusions: The main limit of the present systematic review is the scarcity of papers with an adequate and consistent methodology regarding the data collection and analysis and the lack of RCTs and large well-designed long-term trials. Survival and success rates of implants placed in the areas treated with titanium grids were comparable to those of implants placed in native, non-regenerated bone and of implants placed in bone regenerated with resorbable and non-resorbable membranes. [ABSTRACT FROM AUTHOR]

Background: Gingival recession (GR) defects can be treated by various methods, including aceilular dermal matrix (ADM) or coronally advanced flaps (CAFs). The aim of this histomorphometric experiment is to compare the efficacy of ADM and CAF for treating GR defects in dogs. Methods: In eight beagle dogs, a critical-size labial GR defect was surgically induced on bilateral maxillary cuspids under general anesthesia. Test sites received ADM and CAF, and control sites underwent CAF treatment alone. Plaque index (PI), bleeding index (BI), and gingival index (GI) were measured at 4 weeks (baseline), 8 weeks, and 16 weeks. Width of keratinized gingiva (KG) was determined at baseline and at 16 weeks. Depth of recession and width of GR below the cemento-enamel junction (CEJ) was also determined. After 4 months, animals were sacrificed, and jaw blocks were histomorphometrically assessed for tissue thickness and distance from the stent to the gingival margin (GM) and to the CEJ. Results: At 4-, 8-, and 16-week intervals, there was no significant difference in the BI, GI, and PI at the test and control sites. At 16 weeks, thickness of KG was significantly higher at the control sites than test sites (P <0.01). There was no difference in the midfacial recession depth and recession width at the test and control sites at baseline and before euthanasia (16 weeks). Histomorphometrically, there was no significant difference in tissue thicknesses and distances from the stent to the GM and CEJ in the test and control sites. Conclusion: ADM might yield similar results to a CAF alone and could decrease the amount of KG. [ABSTRACT FROM AUTHOR]

Objective: Direct laser metal forming (DLMF) is a procedure in which a high-power laser beam is directed onto a metal powder bed and programmed to fuse particles according to a computer-aided design file, generating a thin metal layer. This histologic study evaluated the bone-to-implant contact (BIC%) around immediately loaded DLMF transitional implants retrieved after 2 months from posterior human maxillae. Methods: Twelve totally edentulous individuals (mean age, 66.14 ± 2.11 years) received DLMF transitional implants divided in twelve immediately loaded (IL) and twelve unloaded (UI) implants. These transitional implants were placed between conventional implants to support the interim complete maxillary denture during the healing period. After 8 weeks, the transitional implants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results: Mature woven preexisting bone lined by newly formed bone in early stages of maturation were found around all retrieved implants. Histometric evaluation indicated that the mean BIC% was 45.20 ± 7.68% and 34.10 ± 7.85% for IL and UI, respectively (P <0.05). Conclusion: The present data obtained in humans showed that, although both IL and UI presented good BIC%, IL DLMF implants had a higher BIC% in the posterior maxilla. [ABSTRACT FROM AUTHOR]

ABSTRACT Purpose: In vivo bone response was assessed by removal torque, hystological and histometrical analysis on a recently developed biomedical Ti-15Mo alloy, after surface modification by laser beam irradiation, installed in the tibia of rabbits. Materials and Methods: A total of 32 wide cylindrical Ti-15Mo dental implants were obtained (10 mm × 3.75 mm). The implants were divided into two groups: 1) control samples (Machined surface - MS) and 2) implants with their surface modified by Laser beam-irradiation (Test samples - LS). Six implants of each surface were used for removal torque test and 10 of each surface for histological and histometrical analysis. The implants were placed in the tibial metaphyses of rabbits. Results: Average removal torque was 51.5 Ncm to MS and >90 Ncm to LS. Bone-to-implant-contact percentage was significantly higher for LS implants both in the cortical and marrow regions. Conclusions: The present study demonstrated that laser treated Ti-15Mo alloys are promising materials for biomedical application. [ABSTRACT FROM AUTHOR]

Objectives Various grafts or combination of graft materials have been used in sinus floor augmentations, and human histological reports on their performance are available, although limited in number. Histological analysis of the regenerated tissues will provide useful information regarding the nature and amount of newly formed bone. Aim of the present study was a histological and histomorphometric evaluation, in humans, of specimens retrieved from sinuses augmented with phycogene hydroxyapatite, biphasic calcium phosphate ceramics, calcium carbonate, porcine bone and anorganic bovine bone, after a healing period of 6 months. Materials and methods A total of 15 patients, undergoing 30 sinus augmentation procedures with five different biomaterials, participated in this study. A total of 82 titanium dental implants were inserted in the augmented sinuses after a healing period of 6 months. A total of 60 bone cores, 2 for each augmented sinus, 12 for every biomaterial, were retrieved and all were stored immediately in 10% buffered formalin and processed to obtain thin ground sections. Results In all biomaterials, many grafted particles were lined and, sometimes, bridged by newly formed bone. Some biomaterials particles appeared to be partially resorbed and substituted by newly formed bone. Histomorphometry showed that, in all biomaterials, newly formed bone and residual grafted material particles represented about 30%. Conclusions Longer term histological and histomorphometric studies will be necessary to understand better the resorption times of all these biomaterials. The high interconnecting microporosity allowed, in all the present biomaterials, the ingrowth of newly formed bone and vessels in the pores of the partially resorbed particles. In conclusion, within the limitations of the present study, the data provided support the fact that all these biomaterials can be used, successfully, in sinus augmentation procedures. [ABSTRACT FROM AUTHOR]

Background: Two-piece implants present gaps and cavities between the implant and the abutment, and these hollow spaces can act as a trap for bacteria. The aim of the present in vitro study was to evaluate the migration of two different microbial species from the inside to the outside of the implant-abutment assembly in three different connection types. Methods: A total of 30 implants (10 implants per group) were used. The implants presented a screwed trilobed connection (group 1), a cemented connection (group 2), and an internal conical connection (group 3). The inner parts of five implants, per group, were inoculated with Pseudomonas aeruginosa suspension and the remaining five implants, per group, with Aggregatibacter actinomycetemcomitans. The penetration of bacteria into the surrounding solution was determined by the observation of turbidity of the broth. Results: In group 1, bacterial contamination was found in six of 10 implants. In group 2, no contaminated samples were found. In group 3, bacterial contamination was found in one implant of 10. Statistically significant differences were detected between group ] versus group 3 (P <0.05) and between group 1 versus group 2 (P<0.01), whereas no significant differences were found when comparing group 2 versus group 3 (P>0.05). Conclusion: The present study confirms previous results about the hermeticity of the cement-retained implant-abutment assembly, the very low permeability to bacteria of the conical implant-abutment connection, and the high prevalence of bacterial penetration of screw-retained implant-abutment assemblies. [ABSTRACT FROM AUTHOR]

Background: Stability of peri-implant crestal bone plays a relevant role relative to the presence or absence of interdental papilla. Several factors can contribute to the crestal bone resorption observed around two-piece implants, such as the presence of a microgap at the level of the implant-abutment junction, the type of connection between implant and prosthetic components, the implant positioning relative to the alveolar crest, and the interimplant distance. Subcrestal positioning of dental implants has been proposed to decrease the risk of exposure of the metal of the top of the implant or of the abutment margin, and to get enough space in a vertical dimension to create a harmoniously esthetic emergence profile. Methods: The present retrospective histologic study was performed to evaluate dental implants retrieved from human jaws that had been inserted in an equicrestal or subcrestal position. A total of nine implants were evaluated: five of these had been inserted in an equicrestal position, whereas the other four had been positioned subcrestally (1 to 3 mm). Results: In all subcrestally placed implants, preexisting and newly formed bone was found over the implant shoulder. In the equicrestal implants, crestal bone resorption (0.5 to 1.5 mm) was present around all implants. Conclusion: The subcrestal position of the implants resulted in bone located above the implant shoulder. [ABSTRACT FROM AUTHOR]

In the past few years, the occurrence of an oral lesion, called osteonecrosis of the jaw (ONJ), has been increasingly reported in patients undergoing treatment with bisphosphonates (BPs); however, few published histological studies of ONJ can be found in the literature. The aim of the present case was to report an occurrence of ONJ after implant insertion. Multiple myeloma was diagnosed to a 65-year-old female. After 5 years of treatment with intravenous clodronate, two dental implants were inserted in the mandibular molar region. No preexisting bone lesions were present at a preoperative panoramic radiography. Before implant insertion, the patient had suspended the treatment with clodronate for 3 months. Four months after the implant insertion, a breakdown of the oral mucosa covering the implants occurred with a purulent discharge; periapical radiolucency was present around both implants. An en-block resection on the alveolar bone including the two implants was performed. No signs of recurrence of the lesion were observed after a follow-up of 20 months. At the interface of one of the implants, a gap was observed between bone and implant. This bone was nonvital, and many osteocyte lacunae were empty. Moreover, this bone appeared to be partially demineralised. No newly formed bone or osteoblasts were present. Bone trabeculae were observed, on the other hand, within the apical implant threads of the other implant. A close connection was observed between this bone and the implant surface. The histological findings showed some areas with osseointegration in patients undergoing BP treatment for malignant disease; however, any invasive procedure can determine the onset of osteonecrosis. In conclusion, there is certainly a temporal association between BP use and development of ONJ, but a correlation does not necessarily mean causation. Moreover, generalizations about this complex relationship cannot be made on the basis of a single case report. In patients undergoing intravenous treatment, clinicians must be aware of the increased risk of implant failure and, probably, implant insertion should be avoided at all until more conclusive data are available. [ABSTRACT FROM AUTHOR]

Bone substitutes, such as allografts, xenografts, and alloplasts, have been proposed in several augmentation procedures. The aim of the present study was a histologic and histomorphometric evaluation of specimens retrieved 4 or 6 months after sinus augmentation using cortical porcine bone augmentation material. A total of 77 specimens, retrieved after 4 and 6 months from augmented sinuses, were used in this study. The specimens were processed to be observed under light microscopy. Histomorphometric measurements were presented as means ± standard deviations. Most of the particles were surrounded by newly formed bone with large osteocyte lacunae. Histomorphometry showed that, after 4 months, the newly formed bone represented 28%, marrow spaces 36%, the residual graft material 37%, while, after 6 months, the newly formed bone represented 31%, marrow spaces 34%, while the residual graft material was 37%. The present results show that cortical porcine bone is a biocompatible, osteoconductive biomaterial that can be used for maxillary sinus augmentation procedures without interfering with the normal reparative bone processes. [ABSTRACT FROM AUTHOR]

Physical and bioceramic incorporation surface treatments at the nanometer scale showed higher means of bone-to-implant contact (BIC) and torque values compared with surface topography at the micrometer scale; however, the literature concerning the effect of nanometer scale parameters is sparse. The aim of this study was to evaluate the influence of two different implant surfaces on the percentage bone-to-implant contact (BIC%) and bone osteocyte density in the human posterior maxilla after 2 months of unloaded healing. The implants utilized presented dual acid-etched (DAE) surface and a bioceramic molecular impregnated treatment (Ossean®, Intra-Lock International, Boca Raton, FL, USA) serving as control and test, respectively. Ten subjects (59 ± 9 years of age) received two implants (one of each surface) during conventional implant surgery in the posterior maxilla. After the non-loaded period of 2 months, the implants and the surrounding tissue were removed by means of a trephine and were non-decalcified processed for ground sectioning and analysis of BIC%, bone density in threaded area (BA%), and osteocyte index (Oi). Two DAE implants were found to be clinically unstable at time of retrieval. Histometric evaluation showed significantly higher BIC% and Oi for the test compared to the control surface ( p < .05), and that BA% was not significantly different between groups. Wilcoxon matched pairs test was used to compare the differences of histomorphometric variables between implant surfaces. The significance test was conducted at a 5% level of significance. The histological data suggest that the bioceramic molecular impregnated surface-treated implants positively modulated bone healing at early implantation times compared to the DAE surface. [ABSTRACT FROM AUTHOR]

Background: This prospective and controlled histologic study evaluates the impact of smoking on bone-to-implant contact, the bone density in the threaded area, and the bone density outside the threaded area around microimplants with anodized surface retrieved from human jaws. Methods: A total of 24 subjects (mean age 51.32 ± 7.5 years) were divided in two groups: smokers (n = 13 subjects) and non-smokers (n = 11 subjects). Each subject received one microimplant with oxidized surface during conventional mandible or maxilla implant surgery. After 8 weeks, the microimplants and the surrounding tissue were removed and prepared for histomorphometric analysis. Results: Three. microimplants placed in smokers showed no osseointegration. The newly formed bone showed early stages of maturation, mainly in the non-smokers. Marginal bone loss, gap, and fibrous tissue were present around implants retrieved from smokers. Histometric evaluation indicated that the mean bone-to-implant contact ranged between 25.97% ± 9.02% and 40.01% ± 12.98% for smokers and non-smokers, respectively (P <0.001). Smokers presented 28.17% ± 10.32% of bone density in the threaded area, whereas non-smokers showed 46.34% ± 19.12%. The mean of bone density outside the threaded area ranged between 18.76% and 25.11% for smokers and non-smokers, respectively (P>0.05). Conclusion: The present data obtained in human subjects confirm that smoking has a detrimental effect on early bone tissue response around oxidized implant surfaces. [ABSTRACT FROM AUTHOR]