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Over the years, several bone regeneration procedures have been proposed using natural (autografts, allografts, and xenografts) and synthetic (i.e., metals, ceramics, and polymers) bone grafts. In particular, numerous in vitro and human and animal in vivo studies have been focused on the discovery of innovative and suitable biomaterials for oral and maxillofacial applications in the treatment of severely atrophied jaws. On this basis, the main objective of the present narrative review was to investigate the efficacy of innovative collagenated porcine bone grafts (OsteoBiol®, Tecnoss®, Giaveno, Italy), designed to be as similar as possible to the autologous bone, in several bone regeneration procedures. The scientific publications were screened by means of electronic databases, such as PubMed, Scopus, and Embase, finally selecting only papers that dealt with bone substitutes and scaffolds for bone and soft tissue regeneration. A total of 201 papers have been detected, including in vitro, in vivo, and clinical studies. The effectiveness of over 20 years of translational research demonstrated that these specific porcine bone substitutes are safe and able to improve the biological response and the predictability of the regenerative protocols for the treatment of alveolar and maxillofacial defects. [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]

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]

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]

Background: Little is known about the healing pattern and the osseointegration processes at the interface of implants placed into different grafting materials in man. Anorganic bovine bone (ABB) is a xenogenic material with a high biocompatibility and osteoconductivity. Methods: A 47-year-old patient underwent a monolateral sinus-augmentation procedure using 100% ABB. Two titanium dental implants were inserted at the same time as the grafting procedure. After 6 months, a fixed prosthetic restoration was placed. After a 5-year loading period, the distal implant fractured, and the implant was removed with a 5-mm trephine bur. Results: At low magnification, in the peri-implant bone in the grafted area, many particles of ABB were still present. Bone was always interposed between the ABB particles and the metal surface, and in no case were the graft particles in contact with the implant. No acute or chronic inflammatory cell infiltrate or foreign body reactions were present around the particles or at the bone-implant interface. The tissues around the implant were composed of 40% ± 2.4% bone, 12% ± 2.9% ABB particles, and 50% ± 62% marrow spaces. The percentage of bone-to-implant contact was 48.6% ± 3.7%. Conclusions: A high percentage (~50%) of direct contact between bone and implant, without the interposition of graft material particles, was present ABB had enabled implant integration to take place, which had remained stable for 5 years. [ABSTRACT FROM AUTHOR]

Background: In more than three decades of work of the Retrieval Bank of the Laboratory for Undemineralized Hard Tissue Histology of the University of Chieti-Pescara in Italy, many types of biomaterials were received and evaluated. The present retrospective review aimed to evaluate the histological and biological aspects of the evaluated bone substitute biomaterials., Methods: In the present study, the authors prepared a retrospective analysis after the screening of some databases (PubMed, Scopus, and EMBASE) to find papers published from the Retrieval Bank of the Laboratory for Undermineralized Hard Tissue Histology of the University of Chieti-Pescara analyzing only the papers dealing with bone substitute biomaterials and scaffolds, in the form of granules and block grafts, for bone regeneration procedures., Results: Fifty-two articles were found, including in vitro, in vivo, and clinical studies of different biomaterials. These articles were evaluated and organized in tables for a better understanding., Conclusions: Over three decades of studies have made it possible to assess the quality of many bone substitute biomaterials, helping to improve the physicochemical and biological properties of the biomaterials used in daily clinical practice.

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.

Background : The aim of the present review was to assess the histological and histomorphometrical data from the paper published by our Laboratory on peri-implant bone in dental implants in different loading conditions. Methods : The papers published in different implant loading conditions, in dental implants retrieved from humans, and in the Hard Tissues Research Center of the University of Chieti-Pescara, Italy, were screened on MEDLINE/PubMed, Embase, Scopus, and other electronic databases until 31 December 2018. Only articles that reported the histological and histomorphometrical values of the Bone-Implant Contact (BIC) were selected. Results : The system selection provided a total of 155 papers. The manuscripts included for the narrative review were 57. These papers provided histological and histomorphometrical data. Conclusions : The bone remodeling around dental implants was found to be a dynamic process; loading changed the microstructure of the peri-implant bone; and implants were found to provide a successful function, over several decades, with different range of degrees of BIC in vivo (varying from a little more than 30% to a little more than 90%). Loaded implants presented a 10%-12% higher BIC values when compared to submerged, unloaded implants, and rougher surfaces had, on average, about a 10% higher BIC than machined surfaces.

Purpose: Ultrasonic surgery is a recently developed system for cutting bone with microvibrations. The aim of the current study was a histologic comparison between conventional drills versus ultrasonic surgery devices in implant bed preparation., Methods: Ten bovine ribs were used, and a total of 100 perforations were randomly performed: half (n = 50) (group A) of the perforations were done through conventional drills using a single cylindrical bur (Bone System, Milan, Italy), 13 mm in height and 2 mm in width at a speed of 400 rpm, and the other half (n = 50) (group B) using an ultrasonic device (Surgysonic; Esacrom, Imola Italy), mounted with a diamond-coated cylindrical tip. After implant sites' preparation, the ribs were immediately stored in 10% buffered formalin and processed to obtain thin ground sections., Results: At higher magnification, microcracks at the interface were detected. In group A, they were numerous and showed a thickness and depth ranging from 20 to 120 μm and from 500 to 1000 μm, respectively. In group B, very few or no microcracks were present. Statistically significant differences were found in the microcracks density in the cortical bone but not in the cancellous bone., Conclusions: The findings from this study suggest that ultrasonic implant site preparation showed a higher performance in terms of accuracy and uniformity of the osteotomy cut, compared with conventional rotary instruments. Further studies should be conducted to understand whether a smooth, congruent implant bed able to retain fine bone structures may affect the early phases of bone healing and therefore improve osseointegration.