Re-entry Procedure Research Articles

Histologic evaluation of edentulous alveolar ridge horizontal bone augmentations using a xenogeneic bone substitute and autologous platelet concentrates: a case series.

This case series aimed to assess the efficacy of a novel horizontal ridge augmentation modality using histology. Combinations of "sticky bone" and tenting screws without autologous bone were used as augmentative materials. Five individuals presenting healed, atrophic, partially edentulous sites that required horizontal bone augmentation before implant placement were enrolled. Patients underwent the same augmentation type and 5 months of postoperative reentry procedures. The first surgery served as implant site development, whereas the biopsy and corresponding implant placement were performed during reentry. The bone was qualitatively analyzed using histology and histomorphometry and quantitatively evaluated using CBCT. Four individuals healed uneventfully. Early wound dehiscence occurred in one case. Histology showed favorable bone substitute incorporation into the newly formed bone and intimate contact between de novo bone and graft material in most cases. Histomorphometry revealed an average of 48 ± 28% newly formed bone, 19 ± 13% graft material, and 33 ± 26% soft tissue components. The CBCT-based mean alveolar ridge horizontal increase was 3.9 ± 0.6 mm at 5 months postoperatively. The described augmentation method appears suitable for implant site development resulting in favorable bone quality according to histology. However, clinicians must accommodate 1 to 2 mm of resorption in augmentative material width at the buccal aspect.

Inflatable aerodynamic decelerator for CubeSat reentry and recovery: Altitude effects on the flowfield structure

In the present investigation, numerical simulations are conducted in order to characterize the flowfield structure of Inflatable Aerodynamic Decelerators (IAD) for CubeSat reentry and recovery. IAD may inflate to its full size before the reentry procedure, and it can be used to reduce the velocity and protect the CubeSat against the harsh reentry environment. In addition, by protecting the CubeSat during the reentry, it will be possible to recover and reuse part of it in several missions. In the present investigation, a CubeSat coupled with an IAD system is investigated for altitudes ranging from 115 to 95 km. Due to the considerable degree of rarefaction at these altitudes, the Direct Simulation Monte Carlo Method was employed to compute the macroscopic properties around the nanosatellite. According to the computational results, it was observed the formation of a highly diffuse shock wave upstream of the IAD at 115 km. As the CubeSat moves through an ever-thickening atmosphere, a significant increase in the shock wave temperature, pressure, and density measured along the stagnation streamline was noticed. As the flow expands over the IAD shoulder, the wake region is characterized by a significant decrease in the macroscopic properties, and no recirculation region was formed for the altitudes considered in the present investigation.

Comparison of Injectable Biphasic Calcium Phosphate and a Bovine Xenograft in Socket Preservation: Qualitative and Quantitative Histologic Study in Humans.

This study is the first histologic evaluation of an injectable biphasic calcium phosphate (IBCP) in humans six months after socket preservation according to the principles of guided bone regeneration. After tooth extraction, the alveolar ridge of 21 patients was augmented with IBCP (maxresorb® inject) in the test group, while 20 patients in the control group received a bovine xenograft (BX) (cerabone®). Six months after augmentation, a reentry procedure was performed to collect biopsies of regenerated bone for qualitative and quantitative histologic analysis. A total of 20 biopsies were taken for analysis. Qualitative histologic analysis showed complete integration of the biomaterial and no inflammatory tissue reaction, indicating the biocompatibility of the bone grafts and the surrounding tissue in both groups. Histomorphometric analysis showed comparable results in terms of newly formed bone (IBCP: 26.47 ± 14.71%, BX: 30.47 ± 16.39%) and residual biomaterial (IBCP: 13.1 ± 14.07%, BX: 17.89 ± 11.81%), with no significant difference found across groups (p > 0.05, Mann—Whitney U test). Statistical significance between groups was found in the result of soft tissue percentage (IBCP: 60.43 ± 12.73%, BX: 51.64 ± 14.63%, p = 0.046, Mann—Whitney U test). To conclude, IBCP and BX showed good osteoconductivity and biocompatibility with comparable new bone formation six months after alveolar ridge preservation.

An optimal heat-flux targeting procedure for LEO re-entry of reusable vehicles

This paper addresses the feasibility analysis of a re-entry flight strategy from low Earth orbit, developed for an innovative re-usable wing-body concept, having a rather high surface-to-mass ratio. The re-entry procedure envisages a longer and gradual dissipation of vehicle's total energy, carried out at a flight path angle lower than typical Shuttle-like values. Hence, the heat flux is kept constant at a predicted threshold, thus allowing the radiative cooling of the spacecraft heatshield at a suitable temperature. The selected flight approach relies on a prescribed guidance law which modulates the glider angle of attack as function of Mach number, to assure the desired convective heat flux level for a certain time. Based on a low-flight path assumption, analytical considerations are derived to evaluate geometric, aerodynamic, and flight parameters that influence the convective heat flux. Furthermore, candidate guidance laws are determined formulating an optimization-based heat flux targeting procedure. The relevance of aerodynamic performances is also underlined, provided that, by results high lift configurations dictate lower angles of attack and vice versa. Analytical and numerical results evidence existing relation between surface-to-mass ratio, lift-to-drag ratio and flight duration time, that can be used “on design” to modulate the aerothermal loading. The current approach is suitable to explore less challenging aerothermal environments in order to improve reliability and affordability of space operations in the near Earth space.

Clinical and radiographic outcomes of reentry lateral sinus floor elevation after a complete membrane perforation.

Although small perforation of the maxillary sinus schneiderian membrane is a well-documented complication during lateral sinus floor elevation (LSFE), complete perforations larger than 10 mm often result in discontinuation of surgery. Reports on reentry LSFE and its long-term outcomes are sparse. To evaluate the long-term outcomes of reentry LSFE following complete membrane perforation to elucidate the technical details of the reentry procedure. We assessed the medical records of all patients receiving LSFE from 2008 to 2017 in the Department of Oral Implantology, Peking University Hospital of Stomatology. Twenty-two patients receiving reentry LSFE after complete membrane perforation were enrolled. Data were recorded using cone beam computer tomography: including the residual bone height, membrane thickness of the sinus prior to surgery (MT1 ), and before reentry (MT2 ), and height of the bone graft during the reentry procedure (HBG). Cumulative survival rate of implants (CSR), marginal bone loss (MBL), and subsequent complications were also recorded. From 2008 to 2017, 2023 consecutive patients (2262 sinuses) who underwent LSFE were screened. Complete membrane perforation occurred in 28 patients and resulted in discontinuation of surgery (1.2%). Twenty two patients were enrolled and received reentry LSFE within 3-6 months. Two patients undergoing the reentry procedure were suspended due to excessive membrane perforation, while the other 20 finished reentry sinus bone graft. In the reentry procedure, the HBG was 9.73 ± 2.67 mm with 34 implant placements. The MT1 and MT2 were 1.03 ± 0.43 and 1.91 ± 1.45 mm, respectively, showing a statistically significant difference (P < .05). After a follow-up of 2-10 years, CSR was 97.1%, and MBL was 0.64 ± 0.50 mm. The long-term outcome of reentry LSFE is predictable and reentry LSFE offers a reliable alternative following complete membrane perforation. However, the procedure is relatively sensitive and should be performed by experienced surgeons.

Efficacy of lateral bone augmentation performed simultaneously with dental implant placement: A systematic review and meta-analysis.

To analyse the evidence regarding the efficacy of lateral bone augmentation procedures in terms of defect resolution in cases of horizontal ridge deficiencies after implant placement. Included studies met the following inclusion criteria: randomized controlled trials (RCTs) or controlled clinical trials (CCTs), re-entry procedure to assess defect resolution, minimum of 10 patients (5 per group). Meta-analyses were performed whenever possible, including subgroup analysis based on membranes and grafting materials. Twenty-eight publications (20 short-term, 8 follow-up studies) were included. The most often used type of intervention was a xenogeneic particulated grafting material (XE) and a resorbable collagen membrane (CM). The mean defect height at baseline amounted to 5.1mm (range 2.4-7.8) and decreased to a mean of 0.9mm (range 0.2-2.2) at re-entry, and the mean defect resolution was 81.3% (range 56.4%-97.1%). Defect height reduction was not significantly different using CM+XE as control treatment compared to the combined data of the respective test groups [n=11; weighted mean difference (WMD)=-0.006mm; 95% CI, -0.61, 0.60; p=0.985]. The absence of any lateral bone augmentation was less favourable than the conjunction of a membrane and a bone grafting material (n=1; MD=-1.96mm; 95% CI, -3.48, -0.44; p=0.011). The lack of a grafting material was less favourable than the conjunction of grafting material and membrane (n=1; MD=-2.44mm; 95% CI, -4.53, -0.35; p=0.022), and the addition of a membrane compared to a grafting material alone was more favourable (n=3; WMD=0.97mm; 95% CI, 0.31, 1.64; p=0.004). Lateral bone augmentation is a successful treatment modality. For optimal defect height reduction, a barrier membrane and a grafting material should be combined.

Preservation of Dental Sockets Filled with Composite Bovine Bone. A Single-Blind Randomized Clinical Trial.

The purpose of this study was to evaluate the preservation of alveolar dimensions in human fresh extraction sockets filled with a composite bovine bone graft by means of design of single-blind randomized clinical trial. Forty participants had monoradicular teeth extracted (one teeth in each participant), and after were randomly divided into 2 groups: individuals whose fresh sockets were filled with the composite heterologous bone graft (Biomaterial Group), or with blood clot (Control Group). After extraction, the fresh sockets were measured at their greatest mesiodistal (MD) and bucco-lingual/palatal (BL/P) distance. Primary closure of the soft tissue was performed with a fibro-mucosal plug. After 120 post-operative days, the re-entry procedure was performed and the largest MD and BL/P measurements were again obtained to calculate the remodeling of the alveolar bone measured in percentage. In the biomaterial group, a percentage reduction of 1.62% and 3.29% in the MD and BL/P dimensions was observed 120 days after the extractions, whereas a reduction of 4.97% and 7.18% in the MD and BL/P dimensions occurred in the control group. There was a statistically significant difference (p<0.05) between the two groups for the bucco-palatal and mesiodistal measurements in the maxilla. In view of the results obtained, it can be concluded that composite bovine bone graft limited but did not impede alveolar bone remodeling.

A simplified soft tissue management for peri-implant bone augmentation.

This case series illustrates a simplified soft tissue management, namely, the subperiosteal peri-implant augmented layer (SPAL), to increase hard and soft tissue dimensions at the most coronal portion of an implant. Twenty-seven implants in 16 patients presenting either a buccal bone dehiscence or a thin (< 1 mm) buccal cortical bone plate (BCBP) were consecutively treated. Briefly, a split-thickness flap (namely, the mucosal layer) was raised on the buccal aspect. Then, the periosteal layer was elevated from the bone crest. A full-thickness flap was elevated on the oral aspect. After implant site preparation, a xenograft was used to fill the space between the periosteal layer and the BCBP and/or exposed implant surface and, if present, to completely correct the bone dehiscence. The periosteal layer was sutured to the oral flap. The mucosal layer was coronally advanced and sutured to submerge both the graft and the implants. At 3 to 6 months, a re-entry procedure for implant exposure was performed. Healing was uneventful, with no signs of infection in all cases. A wound dehiscence was observed in three implants in two patients at 2 weeks postsurgery. Out of 15 implants showing an initial bone dehiscence, 12 implants (80%) showed a complete resolution, with a subperiosteal tissue thickness (SPTT) at the time of re-entry of 3.1 ± 1.0 mm. Three implants presented a residual dehiscence of 1 mm (two implants) or 2 mm (one implant), with a SPTT of at least 2 mm. Out of 12 implants showing a thin BCBP at implant placement, 10 implants (90%) revealed a SPTT ≥ 2 at the time of re-entry. Two implants revealed a SPTT of 1 mm. The SPAL technique represents a valuable simplified surgical approach associated with a low rate of complications in the treatment of peri-implant bone dehiscence and in the horizontal augmentation of peri-implant tissue thickness.

Vasoactive-Ventilation-Renal Score Predicts Cardiac Care Unit Length of Stay in Patients Undergoing Re-Entry Sternotomy: A Derivation Study

Background: The vasoactive-ventilation-renal (VVR) score includes pulmonary and renal dysfunctions not previously addressed by the vasoactive inotrope score (VIS) and may be a better predictor of cardiac care unit (CCU) length of stay (LOS) in patients undergoing re-entry sternotomy (defined as no earlier than 30 days after previous sternotomy) for congenital heart disease (CHD). Methods: Patients undergoing re-entry sternotomy for CHD from August 1, 2009 to June 30, 2016 were studied retrospectively. A total of 96 patients undergoing 133 re-entry procedures were identified. VVR scores were calculated on CCU admission post-procedure (at 0 hour), 24-hour, and 48-hour after admission to the CCU. The response variable was CCU LOS. Recursive partition analysis identified variables predicting LOS. Results: 133 re-entry sternotomies in 96 patients made up the samples of the database; 11 samples were removed due to incomplete data or placement on ECMO. Of the initial 25 features, 5 were removed for near zero variance and 3 categorical features were removed for non-information. Covariance analysis did not demonstrate any significant correlation amongst the remaining features. Initial recursive tree regression using ANOVA, cross validation and conditional predictive p-value (cp) = 0.01 produced 3 trees. The tree with lowest cross validation error was selected. The resulting 2 split trees with ventilator days less than 20 days and VVR score at 48 hours greater than 23 identified three CCU LOS groups with mean CCU LOS of 77.6, 55.1, and 9.5 days. Conclusions: Recursive partition analysis identified ventilator days greater than 20 days and the sub-population VVR at 48 hours as predictive of CCU LOS in patients undergoing re-entry sternotomy for CHD.

Safety and performance of a novel collagenated xenogeneic bone block for lateral alveolar crest augmentation for staged implant placement

To evaluate the performance and safety of placing a collagenated xenogeneic bone block (CXBB) graft for the lateral bone augmentation of the alveolar crest prior to implant placement. In patients with single or multiple tooth gaps and a severe horizontal collapse of the alveolar ridge, a ridge augmentation procedure was performed using CXBB fixated with osteosynthesis screws to the atrophic bone crest and complemented with deproteinized bovine bone mineral particles (DBBM) and a native bilayer collagen membrane (NBCM). Patients were examined with CBCT prior to and 24weeks after the augmentation. Twenty-six weeks postoperatively, a re-entry procedure was performed to evaluate the bone width and availability for adequate implant placement. Fifteen patients received 28 CXBB, and in 13 patients, a re-entry procedure was performed. Eleven patients (84.6%) gained enough bone volume for implant insertion without additional contouring or secondary bone augmentation. The mean crest width at baseline was 2.83mm (SD 0.57), and the mean crest width at re-entry was 6.90mm (SD 1.22), with a mean ridge width increase of 4.12mm (SD 1.32). Soft tissue dehiscence occurred during the follow-up in 5 of 14 patients (35.7%) at various time points. In addition, there was a high incidence of early implant loss (30.8% [patient-based]). CXBB achieved significant horizontal crestal width gains allowing a secondary implant placement in the majority of the patients. However, the occurrence of soft tissue dehiscence may notably affect the outcome of the subsequent implant therapy.

Histomorphometric and immunohistochemical evaluation of collagen containing xenogeneic bone blocks used for lateral bone augmentation in staged implant placement

BackgroundThe osteoconductive properties of collagen containing xenogeneic bone blocks (CCXBB) remain unclear. The aim of this prospective single-arm clinical study was to assess the histological outcomes of CCXBB blocks used as bone replacement grafts for lateral bone augmentation procedures.MethodsIn 15 patients with severe horizontal alveolar ridge resorption, lateral augmentation procedures were performed using CCXBB as bone replacement grafts. Twenty-six weeks postoperatively, a re-entry procedure was performed to evaluate the bone width for adequate implant placement and two histological specimens were retrieved from each patient, one being processed for ground sectioning and the other for decalcified paraffin-included sections. In non-decalcified sections, the relative proportions occupied by bone, biomaterials, and connective tissue present in the biopsies were identified. In de-calcified sections, structures and cells positive for osteopontin (OPN), tartrate-resistant acid phosphatase activity (TRAP), osteocalcin (OSC), and alkaline phosphatase (ALP) were assessed.ResultsSoft tissue dehiscence occurred during the follow-up in 5 out of 15 patients (33.3%). The mean crest width at baseline was 2.78 mm (SD 0.57) and the mean crest width at re-entry was 6.90 mm (SD 1.22), with a mean ridge width increase of 4.12 mm (SD 1.32). Twenty-six bone biopsies were obtained from 13 patients. Histomorphometric analysis showed a mean of 26.90% (SD 12.21) of mineralized vital bone (MVB), 21.37% (SD 7.36) of residual CCXBB, 47.13% (SD 19.15) of non-mineralized tissue, and 0.92% of DBBM. The immunohistochemical analysis revealed a large number of OPN-positive cells 8.12% (SD 4.73), a lower proportion of TRAP positive multinuclear cells 5.09% (SD 4.91), OSC-positive cells 4.09% (SD 4.34), and a limited amount of ALP positive cells 1.63% (SD 2).ConclusionsCCXBB achieved significant horizontal crestal width allowing for staged implant placement in most of the patients. In light of the histological outcomes and implant failures, special attention must be placed to prevent soft tissue dehiscence when CCXBB is used in severe atrophic alveolar crests.

Case report on managing incomplete bone formation after bilateral sinus augmentation using a palatal approach and a dilating balloon technique

BackgroundPatients with resorbed edentulous alveolar ridges in the posterior maxilla often require lateral window sinus augmentation procedures prior to implant placement. Lateral window sinus augmentation procedures can produce incomplete bone augmentation as consequence of surgical and healing complications producing unusual and complex sinus anatomy. Although incomplete bone formation after sinus augmentation has been described in a previous case reports, this is the first case report that describes grafting these compromised sites prior to implant placement.Case presentationA 65-year-old male patient with no known medical conditions presented with severe chronic localized periodontitis and a combined periodontal-endodontic lesion affecting three first molars. Initial ridge preservation and lateral window sinus augmentation resulted in incomplete bone formation and complex sinus floor anatomy on both right and left sides. A dilating balloon technique on one side and a palatal approach on the other side were utilized for additional sinus augmentation using particulate allograft and resorbable collagen membranes. Healing was uneventful, and implants could be placed and restored at all sites. Periodontal maintenance was conducted every 3 months, and the implants have been in function and periodontally healthy for 2 years.ConclusionDespite initial failure of sinus augmentation to produce suitable implant sites, it is possible to rescue these sites with re-entry grafting procedures and allow successful implant placement and restoration.

The efficacy of transgingival probing in class II buccal furcation defects treated by guided tissue regeneration.

Background:The objectives of the present study were to establish transgingival probing as an evaluating method in the clinical studies of periodontal regenerative techniques and to compare the effectiveness of transgingival probing to the surgical entry.Materials and Methods:Ten systemically healthy persons (20–50 years) with moderate to severe chronic periodontitis participated in this study. These cases were recruited into the study only when they fulfilled the eligibility criteria. Vertical probing depth (VPD) and horizontal probing depth (HPD) of furcation defects were measured with and without opening the flap, following local anesthesia during initial surgery and at 6 months after collagen membrane placement. The defect fill (DF) was also noted. The mean measurements of clinical parameters were compared by two-tailed paired t-test at 5% level of significance.Results:The difference between the measurements of VPD and HPD taken during transgingival probing and after opening the flap was lie in the range of 0.10–0.30 mm at the time of initial surgery and 6 months after surgery that was not statistically significant. Persons experienced slight discomfort or pain during opening the flap as compared to transgingival probing, and this method was also appreciated by the patients as it is easy, simple and does not involve the surgical procedure.Conclusion:The results of the study suggest that measurements recorded during transgingival probing and after opening the flap do not influence the required outcome of regenerative therapies, i.e., DF that was not statistically significant difference from surgical reentry. Therefore, it was concluded that transgingival probing could be used as evaluating parameters to see the outcome of regenerative surgeries and the surgical reentry procedure may be avoided because it is a second surgical procedure, time-consuming and interrupts the healing process.

Establishing a reentry procedure for human immunodeficiency virus screening-reactive donors in China.

Screening of blood donors for antibody to human immunodeficiency virus Types 1 and 2 (anti-HIV-1/2) and/or HIV nucleic acid test (NAT) is a well-established venue to prevent HIV transfusion-transmitted disease. However, with the current available technologies, HIV testing may result in donor loss due to false-positive results. This study intended to establish a donor reentry procedure for HIV screening-reactive donors in China. From September 1, 2013, to August 31, 2014, a total of 465 donors from 14 Chinese blood centers were enrolled in this study. Enrollment criteria include all donors who were screened reactive or belonged to the "gray zone" by enzyme-linked immunosorbent assay and/or reactive by NAT when tested at the local blood centers. All donor samples were sent to a central HIV confirmation laboratory where anti-HIV-1/2 and HIV individual-donation NATs were conducted. If the results were reactive for anti-HIV-1/2, then the samples were tested with a recombinant immunoblot assay. Based on the repeat testing at the central HIV confirmation laboratory 8 or 16 weeks after the study, 252 donors of 465 (54.2%) who completed the study could be classified in two categories for HIV status: 45 (18%) true positive and 207 (82%) false positive. A total of 213 of 465 (45.8%) donors were lost on follow-up and, thus, their HIV status cannot be determined with certainty. Based on these data, a donor reentry procedure was proposed. Based on our proposed donor reentry procedure for HIV screening-reactive donors, a majority of screening-positive donors (82%, 207/252) can be reentered safely.

Deproteinized bovine bone remodeling pattern in alveolar socket: a clinical immunohistological evaluation.

Considering the low rate of deproteinized bovine bone (DBB) graft resorption in vivo and vitro, the aim of this study was to investigate, through an immunohistochemical method, DBB remodeling patterns in human. Socket preservation, a highly documented and affirmed technique, was selected as the best in vitro model to analyze DBB effect on bone remodeling. Following premolar extraction (T0), 20 patients were randomized into two treatment groups. In the test group (t), the alveolar sockets were grafted with DBB, while in the control group (c) no bone graft was applied and the alveolar sockets were left to heal spontaneously. After 5 months, a re-entry procedure was performed, and one implant was placed according to manufacturer's protocols (T1). Bone biopsies were harvested for each patient both at T0 and at T1. On the bone samples, immunohistochemical investigations were performed to analyze BMP-2, BMP-7, ALP, IL-6, TNF-α expression. Bone morphogenetic proteins were more expressed in the control group than in the test group (BMP-2: P < 0.001; BMP-7: P = 0.017), while TNF-α value was larger in the test group (P < 0.001); no statistically significant differences were observed for the other markers. When considering time as the main variable, statistically significant differences were found for BMP-2 (P < 0.001), BMP-7 (P < 0.001), IL-6 (P < 0.001), ALP (P < 0.05), and TNF-α (P < 0.001). Significant interaction between groups and time was found for BMP-2 (P < 0.001), BMP-7 (P < 0.001), TNF-α (P < 0.001). Deproteinized bovine bone guarantees the activity of bone remodeling processes in human extraction socket at 5 months of healing, bringing to a higher expression of anabolic and catabolic bone markers.

Flap versus flapless procedure for ridge preservation in alveolar extraction sockets: a histological evaluation in a randomized clinical trial

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. 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. 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. No histological and histomorphometrical differences were observed when comparing the flap and the flapless technique for tooth extraction and socket grafting procedures.

EComment. Efforts to further enhance the safety of sternal re-opening in the paediatric age group

We thank Gandolfo et al. for their effective and easy reproducible technique for managing major vessel injuries during chest re-entry in children [1]. As diagnostic and therapeutic interventions in congenital heart diseases advance progressively, cardiac surgeons have begun to deal with chest re-opening more frequently. Although major venous damages like innominate vein can be managed by a Fogarty catheter, cardiac surgeons are still facing challenging problems, such as damage of cardiac chambers, retrosternal right ventricle to pulmonary artery conduits and ascending aortic aneurysms during the re-sternotomy procedures performed in children. In such cases, we believe that the inflation of Fogarty catheters may even enlarge the defect and make it more uncontrollable in an incomplete sternotomy. In our practice, patients with a sternotomy history are carefully evaluated before the operation. Although the best option in imaging work-up is computed tomography, its routine usage is avoided so as not to increase the exposure of ionizing radiation in the paediatric age group. In most of the patients with redo cardiac surgery, magnetic resonance angiography or lateral projection of cardiac cine-angiography studies demonstrate the potential adhesions of the anatomic structures to the posterior part of the sternum. At the operation, we regularly mark the femoral vessels with Doppler ultrasonography and prepare a cardiopulmonary bypass (CPB) set-up before initiating the incision. The skin incision is performed subsequently, the sternal wires are untwisted and an oscillating saw is used to open the anterior table of the sternum until contact with the sternal wires at the posterior side is felt. The untwisted wires are held with clamps and the sides of the sternum are pulled upwards in which a lateral retraction force is strictly avoided. Afterwards, the posterior table of the sternum is carefully opened starting with xiphoid process towards the jugular fossa with the aid of Mayo scissors. We believe hyperinflation of the lungs, which decompresses the right atrium and ventricle, is a safe and easy measure during this part of the re-entry process [2]. We neither use electrocautery nor blunt digital manipulation for the dissection of the mediastinum. As described by Holst et al. we can clinically group cardiac injuries during sternal re-entry procedures into two categories [3]. A cardiac injury in re-sternotomy is an anticipated (i.e. expected) injury when there is a conduit, an aortic aneurysm, an enlarged right atrium or ventricle which is adherent to the posterior surface of the sternum. In such cases, we prefer to initiate CPB with femoral arterial and venous cannulation before sternal re-entry. This provides us with a safer re-entry process in the mediastinum with decompressed cardiac chambers. The main disadvantage of initiating CPB at the early stage of surgery is the prolonged duration of CPB and uneasiness of controlling the haemostasis in a heparinized patient. CPB may be discontinued after the safe entry to the mediastinum and dissection may be completed off-pump in order to shorten the CPB time. In unanticipated injuries, when a massive bleeding occurs, we discontinue the re-sternotomy and join the two sides of the sternum with two towel clamps. The femoral artery and vein are then promptly cannulated before further dissection at the mediastinum after which CPB is initiated. As a result, besides meticulous surgical technique and judicious usage of CPB, we believe that simple and easily applicable precautions can decrease the incidence of cardiac injuries being encountered during sternal re-opening procedures. These precautions will obviously stipulate a prudent, safe and bloodless operative field for the surgical team. Conflict of interest: none declared.

Implants placed in fresh extraction sockets in the maxilla: clinical and radiographic outcomes from a 3‐year follow‐up examination

The aim of this prospective, randomized, controlled multicenter study was to determine the 3-year efficacy and stability of the soft and hard tissues at implants with a different geometry that were placed in fresh extraction sockets. Implants with two different configurations, cylindrical (Group A) or conical/cylindrical (Group B) were installed, and healing abutments were attached. Sixteen weeks after implant placement, subjects returned for a re-entry procedure. Prosthetic restorations were delivered 22weeks after implant placement. Each subject was placed in a 3-year follow-up program, including examinations at yearly visits including various soft tissue and bone level parameters. The percentage of sites that were considered inflamed during the follow-up period was stable and varied between 8.8% and 10.2%. The radiographic examinations documented improved bone levels at the final examination and the mean improvement from baseline (placement of permanent restoration; PR) amounted to 0.17±0.67mm. More than 70% (54 of 76) of the implants monitored in this study suffered no bone loss during the maintenance period. Moreover, there was an obvious "gain" of interproximal soft tissue volume and at the 3-year examination around 25% of all embrasure gaps were completely filled with "papillae". Both conical/cylindrical and cylindrical implants placed in fresh extraction sockets allowed proper soft and hard tissue healing to occur. At both types of implants, mucosal inflammation was infrequent, marginal bone levels were maintained, and soft tissue volume increased gradually after the placement of the permanent restoration.

Soft and hard tissue alterations around implants placed in an alveolar ridge with a sloped configuration

The aim of this study was to evaluate soft and hard tissue alterations around implants placed in healed, sloped ridge sites. In this prospective multi-center study, 65 patients between 20 and 74years of age and with a need for a single tooth replacement were included. All patients presented with a recipient implant site demonstrating a lingual-buccal bone height discrepancy of 2.0-5.0mm and with a neighboring tooth on its mesial aspect. Implant placement (OsseoSpeed™ Profile implants; Astra Tech AB, Mölndal, Sweden) was performed using a non-submerged installation procedure. The implants were placed in such a way that the sloped part of the device was located at the buccal and most apical position of the osteotomy preparation. As the buccal rim of the implant was positioned at the crestal bone level, the lingual rim became situated either below or at the level of the lingual bone crest. Clinical assessments of bone levels at the buccal and lingual aspects of the implant were carried out immediately after implant installation and at a surgical re-entry procedure performed 16weeks later. Crowns were placed at 21weeks after implant placement. Radiographs were obtained immediately after implant placement, at 16 and 21weeks and at the 1-year re-examination. Clinical assessment of probing pocket depth and clinical attachment levels were carried out at 21weeks and at 1year of follow-up. The alterations of the bone levels that occurred between implant placement and the 16-week surgical re-entry were -0.02mm (lingual) and -0.30mm (buccal). The average change in interproximal bone levels between implant placement and the 1-year re-examination was 0.54mm. Clinical attachment level changes between the 21week and the 1-year examinations varied between 0.1mm gain and 0.1mm loss. Implant placement in an alveolar ridge with a sloped marginal configuration resulted in minor remodeling with preserved discrepancies between buccal and lingual bone levels.

Efficacy of palatal connective tissue graft as a membrane in the treatment of intrabony defects

Background and aims. The aim of this study was to compare clinical effects of two different membranes (palatal connective tissue and collagen) in combination with Bio-Oss in the treatment of intrabony defects. Materials and methods. Fifteen patients who had at least a pair of intrabony defects with an attachment loss of ≥5 mm and an initial osseous defect depth of ≥3 mm participated in this study. Probing pocket depth, clinical attachment level, position of gingival margin, bony defect depth and position of alveolar crest were measured before surgery and in re-entry procedure 9 months after treatment. Results. The results of this study showed that both techniques were effective in the treatment of intra-bony defects and both treatment modalities resulted in significant differences in all the parameters before and after surgery (P<0.05). Conclusion. It was shown that, after treatment, considering all the variables in each group, there were significant improvements, but there were not any statistical differences in any of the variables between the two groups.