Alveolar socket preservation with demineralised bovine bone mineral and a collagen matrix

Carlo Maiorana,Pier Paolo Poli,Matteo Deflorian,Tiziano Testori,Federico Mandelli,Heiner Nagursky,Raffaele Vinci 대한치주과학회 2017 Journal of Periodontal & Implant Science Vol.47 No.4

Purpose: The aim of the present study was to evaluate the healing of post-extraction sockets following alveolar ridge preservation clinically, radiologically, and histologically. Methods: Overall, 7 extraction sockets in 7 patients were grafted with demineralised bovine bone mineral and covered with a porcine-derived non-crosslinked collagen matrix (CM). Soft tissue healing was clinically evaluated on the basis of a specific healing index. Horizontal and vertical ridge dimensional changes were assessed clinically and radiographically at baseline and 6 months after implant placement. For histological and histomorphometric analysis, bone biopsies were harvested from the augmented sites during implant surgery 6 months after the socket preservation procedure. Results: Clinically, healing proceeded uneventfully in all the sockets. A trend towards reduced horizontal and vertical socket dimensions was observed from baseline to the final examination. The mean width and height of resorption were 1.21 mm (P=0.005) and 0.46 mm (P=0.004), respectively. Histologically, residual xenograft particles (31.97%±3.52%) were surrounded by either newly formed bone (16.02%±7.06%) or connective tissue (50.67%±8.42%) without fibrous encapsulation. The CM underwent a physiological substitution process in favour of well-vascularised collagen-rich connective tissue. Conclusions: Socket preservation using demineralised bovine bone mineral in combination with CM provided stable dimensional changes of the alveolar ridge associated with good re-epithelialisation of the soft tissues during a 6-month healing period.

Alveolar socket preservation with demineralised bovine bone mineral and a collagen matrix

Maiorana, Carlo,Poli, Pier Paolo,Deflorian, Matteo,Testori, Tiziano,Mandelli, Federico,Nagursky, Heiner,Vinci, Raffaele Korean Academy of Periodontology 2017 Journal of Periodontal & Implant Science Vol.47 No.4

Purpose: The aim of the present study was to evaluate the healing of post-extraction sockets following alveolar ridge preservation clinically, radiologically, and histologically. Methods: Overall, 7 extraction sockets in 7 patients were grafted with demineralised bovine bone mineral and covered with a porcine-derived non-crosslinked collagen matrix (CM). Soft tissue healing was clinically evaluated on the basis of a specific healing index. Horizontal and vertical ridge dimensional changes were assessed clinically and radiographically at baseline and 6 months after implant placement. For histological and histomorphometric analysis, bone biopsies were harvested from the augmented sites during implant surgery 6 months after the socket preservation procedure. Results: Clinically, healing proceeded uneventfully in all the sockets. A trend towards reduced horizontal and vertical socket dimensions was observed from baseline to the final examination. The mean width and height of resorption were 1.21 mm (P=0.005) and 0.46 mm (P=0.004), respectively. Histologically, residual xenograft particles ($31.97%{\pm}3.52%$) were surrounded by either newly formed bone ($16.02%{\pm}7.06%$) or connective tissue ($50.67%{\pm}8.42%$) without fibrous encapsulation. The CM underwent a physiological substitution process in favour of well-vascularised collagen-rich connective tissue. Conclusions: Socket preservation using demineralised bovine bone mineral in combination with CM provided stable dimensional changes of the alveolar ridge associated with good reepithelialisation of the soft tissues during a 6-month healing period.

Linear buckling analysis of welded girder webs with variable thickness

Emanuele Maiorana,Carlo Pellegrino 국제구조공학회 2011 Steel and Composite Structures, An International J Vol.11 No.6

Steel girder web panels have been subjected in recent decades, to a number of experimental and numerical studies but the mechanisms that regulate the behaviour of the panels composed by two subpanels with different thickness were not deeply studied. Furthermore specific design rules regarding the estimation of the buckling coefficient for panels with variable thickness are not included in the codes even if this is a common situation particularly for steel bridge girders with beams having significant height. In this framework,this work aims to investigate buckling behaviour of steel beams with webs composed of panels with different thicknesses subjected to both in-plane axial compression and bending moment and gives some simplified equations for the estimation of the buckling coefficient.

Elasto-plastic behaviour of perforated steel plates subjected to compression and bending

Emanuele Maiorana,Carlo Pellegrino,Claudio Modena 국제구조공학회 2011 Steel and Composite Structures, An International J Vol.11 No.2

The aim of this work is to provide some insights into the elasto-plastic behaviour of plate girder web square and rectangular panels with centred and eccentric holes under both compression and in-plane bending moment. The numerical study was validated comparing the numerical results obtained for one simple steel plate configuration with the corresponding experimental results, obtained at the University of Padova, observing the influence of the initial out-of-plane imperfections on the force vs. displacement relationship and ultimate strength. Once validated the numerical approach, the effect of bending moment on the stability of the plate is studied and some differences with respect to the uniform compression load case are shown. The influence of dimension and position of the hole, the plate aspect ratio and the steel grade on elasto-plastic behaviour is observed. Some indications regarding the critical slenderness (at which transition from elastic to plastic collapse occurs) are given for square and rectangular plates with symmetric and eccentric holes having small, medium and large diameter.

Linear Elastic Behavior of Circular Holed Steel Box Sections Under Compression

Emanuele Maiorana,Carlo Pellegrino 한국강구조학회 2018 International Journal of Steel Structures Vol.18 No.3

The aim of this work is to provide insights into the linear elastic behavior of steel box sections with centered and eccentric holes, placed at various points on the sides and at the corners of sections, and subjected to uniform compression. The infl uence of the following parameters was observed on stability, mainly through critical deformed shapes: (a) ratio of section aspects, (b) length-to-width ratio, (c) slenderness of sides, (d) diameter of holes, (e) coordinates x and y of the position of the hole on one side of the box section. Indications regarding important design aspects are given: (a) the best location for a single hole, or several holes, in cross-section; (b) the eff ects of circular holes with small, medium and large diameters on the linear buckling factor; (c) the eff ect of symmetric and eccentric holes for purposes of stability; (d) the best performing transversal section for square to rectangular holed box sections, in terms of stability; (e) critical slenderness values at which transition occurs from ultimate strength collapse of stocky box sections and critical elastic stress of slender ones.

A Review of the Fatigue Strength of Shear Bolted Connections

Paolo Zampieri,Andrea Curtarello,Emanuele Maiorana,Carlo Pellegrino 한국강구조학회 2019 International Journal of Steel Structures Vol.19 No.4

Steel bolted connections are the typical joints used in civil engineering but also in the fi eld of mechanical engineering. In particular, slip-resistant bolted connections are those most used in bridge construction. In these applications, bolted joints are subjected to a cyclic load that arises from traffi c fl ow. It is well known that joints are the critical components of constructions subjected to cyclic loads, due to stress concentration that causes fatigue crack initiation. The purpose of this paper is to provide a summary of considerations, from principal scientifi c studies of fatigue strength and the behaviour of bolted joints, as well as an up-to-date comprehensive assessment for future development. In particular, a discussion is proposed regarding the parameters that infl uence the fatigue of bolted joints. The paper concludes with a summary of the major results reported in terms of S–N curves.

Accuracy of computer-aided template-guided oral implant placement: a prospective clinical study

Beretta, Mario,Poli, Pier Paolo,Maiorana, Carlo Korean Academy of Periodontology 2014 Journal of Periodontal & Implant Science Vol.44 No.4

Purpose: The aim of the present study was to evaluate the in vivo accuracy of flapless, computer-aided implant placement by comparing the three-dimensional (3D) position of planned and placed implants through an analysis of linear and angular deviations. Methods: Implant position was virtually planned using 3D planning software based on the functional and aesthetic requirements of the final restorations. Computer-aided design/computer-assisted manufacture technology was used to transfer the virtual plan to the surgical environment. The 3D position of the planned and placed implants, in terms of the linear deviations of the implant head and apex and the angular deviations of the implant axis, was compared by overlapping the pre- and postoperative computed tomography scans using dedicated software. Results: The comparison of 14 implants showed a mean linear deviation of the implant head of 0.56 mm (standard deviation [SD], 0.23), a mean linear deviation of the implant apex of 0.64 mm (SD, 0.29), and a mean angular deviation of the long axis of $2.42^{\circ}$ (SD, 1.02). Conclusions: In the present study, computer-aided flapless implant surgery seemed to provide several advantages to the clinicians as compared to the standard procedure; however, linear and angular deviations are to be expected. Therefore, accurate presurgical planning taking into account anatomical limitations and prosthetic demands is mandatory to ensure a predictable treatment, without incurring possible intra- and postoperative complications.

Accuracy of computer-aided template-guided oral implant placement: a prospective clinical study

Mario Beretta,Pier Paolo Poli,Carlo Maiorana 대한치주과학회 2014 Journal of Periodontal & Implant Science Vol.44 No.4

Purpose: The aim of the present study was to evaluate the in vivo accuracy of flapless, computer-aided implant placement by comparing the three-dimensional (3D) position of planned and placed implants through an analysis of linear and angular deviations. Methods: Implant position was virtually planned using 3D planning software based on the functional and aesthetic requirements of the final restorations. Computer-aided design/computer-assisted manufacture technology was used to transfer the virtual plan to the surgical environment. The 3D position of the planned and placed implants, in terms of the linear deviations of the implant head and apex and the angular deviations of the implant axis, was compared by overlapping the pre- and postoperative computed tomography scans using dedicated software. Results: The comparison of 14 implants showed a mean linear deviation of the implant head of 0.56 mm (standard deviation [SD], 0.23), a mean linear deviation of the implant apex of 0.64 mm (SD, 0.29), and a mean angular deviation of the long axis of 2.42° (SD, 1.02). Conclusions: In the present study, computer-aided flapless implant surgery seemed to provide several advantages to the clinicians as compared to the standard procedure; however, linear and angular deviations are to be expected. Therefore, accurate presurgical planning taking into account anatomical limitations and prosthetic demands is mandatory to ensure a predictable treatment, without incurring possible intra- and postoperative complications.

Risk indicators related to periimplant disease: an observational retrospective cohort study

Pier Paolo Poli,Mario Beretta,Giovanni Battista Grossi,Carlo Maiorana 대한치주과학회 2016 Journal of Periodontal & Implant Science Vol.46 No.4

Purpose: The aim of the present study was to retrospectively investigate the influence of potential risk indicators on the development of peri-implant disease. Methods: Overall, 103 patients referred for implant treatment from 2000 to 2012 were randomly enrolled. The study sample consisted of 421 conventional-length (>6 mm) nonturned titanium implants that were evaluated clinically and radiographically according to preestablished clinical and patient-related parameters by a single investigator. A non-parametric Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model were used for the statistical analysis of the recorded data at the implant level. Results: The diagnosis of peri-implant mucositis and peri-implantitis was made for 173 (41.1%) and 19 (4.5%) implants, respectively. Age (≥65 years), patient adherence (professional hygiene recalls <2/year) and the presence of plaque were associated with higher peri-implant probing-depth values and bleeding-on-probing scores. The logistic regression analysis indicated that age (P=0.001), patient adherence (P=0.03), the absence of keratinized tissue (P=0.03), implants placed in pristine bone (P=0.04), and the presence of peri-implant soft-tissue recession (P=0.000) were strongly associated with the event of peri-implantitis. Conclusions: Within the limitations of this study, patients aged ≥65 years and non-adherent subjects were more prone to develop peri-implant disease. Therefore, early diagnosis and a systematic maintenance-care program are essential for maintaining peri-implant tissue health, especially in older patients.

Risk indicators related to periimplant disease: an observational retrospective cohort study

Poli, Pier Paolo,Beretta, Mario,Grossi, Giovanni Battista,Maiorana, Carlo Korean Academy of Periodontology 2016 Journal of Periodontal & Implant Science Vol.46 No.4

Purpose: The aim of the present study was to retrospectively investigate the influence of potential risk indicators on the development of peri-implant disease. Methods: Overall, 103 patients referred for implant treatment from 2000 to 2012 were randomly enrolled. The study sample consisted of 421 conventional-length (>6 mm) non-turned titanium implants that were evaluated clinically and radiographically according to preestablished clinical and patient-related parameters by a single investigator. A non-parametric Mann-Whitney U test or Kruskal-Wallis rank test and a logistic regression model were used for the statistical analysis of the recorded data at the implant level. Results: The diagnosis of peri-implant mucositis and peri-implantitis was made for 173 (41.1%) and 19 (4.5%) implants, respectively. Age (${\geq}65$ years), patient adherence (professional hygiene recalls <2/year) and the presence of plaque were associated with higher peri-implant probing-depth values and bleeding-on-probing scores. The logistic regression analysis indicated that age (P=0.001), patient adherence (P=0.03), the absence of keratinized tissue (P=0.03), implants placed in pristine bone (P=0.04), and the presence of peri-implant soft-tissue recession (P=0.000) were strongly associated with the event of peri-implantitis. Conclusions: Within the limitations of this study, patients aged ${\geq}65$ years and non-adherent subjects were more prone to develop peri-implant disease. Therefore, early diagnosis and a systematic maintenance-care program are essential for maintaining peri-implant tissue health, especially in older patients.