Libros

Background: Oral implants require adequate bone support, which is often facilitated by bone augmentation when bone volume is insufficient. Autogenous bone (AB) has been considered the 'gold standard' for such procedures due to its osteogenic properties, but it necessitates a second surgical site, which increases patient morbidity. Trial Design and Methods: This study was a randomized, double-blind, split-mouth clinical trial comparing L PRF (leukocyte-platelet rich fibrin) bone-block grafts against a composite graft mixture of 50% AB with 50% deproteinized bovine bone mineral (DBBM) for vertical guided bone regeneration (GBR). The trial included 6 patients needing bilateral vertical GBR before implant placement. A dense polytetrafluoroethylene (d-PTFE) membrane was used for both test and control sites. The primary outcome measure was vertical bone height (VBH) gain, assessed via cone beam computed tomography (CBCT) at 9 and 25 months post-operation. Results: There was no significant difference in VBH gain between the test and control sites at any time points, with a mean VBH gain at implant placement of 4.6 ± 3.0 mm for test sites and 5.2 ± 2.7 mm for control sites. At 1 year after loading of the implants the VBH gain was 3.0 ± 2.8 mm for test sites and 3.8 ± 2.6 mm for control sites (P value 0.96). Complications were minimal and included one implant loss due to infection in a test site. Conclusions: The L-PRF bone block could be a viable alternative to the composite graft, potentially reducing the need for harvesting bone from a second surgical site. Future studies with larger sample sizes are needed to confirm these findings and to explore the biological benefits of integrating the L-PRF bone-block into bone graft materials for oral implantology. Palabras clave: autogenous bone, guided bone regeneration, L-PRF bone-block, vertical bone augmentation, randomized clinical trial, guided bone regeneration

Objective: This study aims to collect data on implant survival, bone volume maintenance, and complications associated with the socket shield technique. Background data: The socket shield technique was introduced in 2010. Since then, several systematic reviews have been published, showing good clinical outcomes. The behaviour of the buccal bone plate is so far not completely understood. Methods: The study involved the placement of 23 implants using the socket shield technique in 20 patients. AstraTech EV implants were used, and no bone substitutes or connective tissue grafts were applied. Patients were monitored for 18 months, recording implant survival, volumetric bone analysis on CBCT scans, interproximal bone levels, bone sounding, pink esthetic scores, and complications. Prosthetic procedures were also described, including temporary and final restorations. Results: A 95.7% cumulative 18-month implant survival rate was obtained using the socket shield technique, with a significant but limited reduction in buccal bone thickness (BBT) after implant placement. One implant did not integrate and two shields were partially exposed. The mean pink esthetic score, 1 year after loading was 12.93 ± 1.22. Conclusion: The study suggests that the socket shield technique can result in limited reduction of the buccal bone volume, with a high implant survival rate. Re-entry studies are recommended to investigate the causes of bone resorption. Palabras clave: bone preservation, immediate implant, implant survival, oral implant, partial extraction, socket shield

Purpose: This study aims to assess the differences between a leukocyte- and platelet-rich fibrin (L-PRF) and deproteinized bovine bone mineral block and a combination of 50% autogenous bone (AB) and 50% deproteinized bovine bone mineral (DBBM) as grafting material for horizontal guided bone regeneration (GBR). Materials and Methods: This randomized double-blind split-mouth clinical trial included 13 subjects requiring bilateral horizontal bone augmentation. Each patient received both treatment modalities: one side of the jaw was treated by GBR with the L-PRF and deproteinized bovine bone mineral block, and the other side with a 50/50 mixture of AB and DBBM. Cone beam computed tomography (CBCT) scans were used to evaluate horizontal bone width (HBW) and buccal bone thickness (BBT) at various time points: baseline (T0), immediately post-augmentation (T1), at implant placement (T2), and one year after abutment connection (T4). Bone sounding (BS) was also used to verify CBCT measurements. Results: No statistically significant differences were found in HBW gain between test (L-PRF) and control (AB/DBBM) sites at any timepoint. Both sites showed significant HBW loss post-implant placement, with more bone volume lost at higher crestal levels (Sh0 > Sh2 > Sh4). At the Sh2 level, 48.8% of the HBW gain at T1 was lost by T4 in test sites, and 46.2% in control sites. Similarly, BBT at Sh2 reduced from 4.7 ± 1.0 mm to 1.3 ± 1.5 mm in test sites and from 2.1 ± 1.0 mm to 0.9 ± 0.8 mm in control sites. Both groups of sites had one complication, resulting in a 91.6% success rate for both treatments. The cumulative survival rate of implants was 100% at 16 months, with a mean interproximal bone level (IBL) loss of 0.2 ± 0.9 mm and 0.1 ± 0.6 mm for test and control sites, respectively. Conclusions: No statistically significant differences were found between the AB/DBBM composite graft and the L-PRF and bovine bone mineral block for horizontal GBR. Significant resorption of grafted volume occurs within 25 months, continuing post-implant placement. Further research with larger sample sizes is needed to confirm these findings and optimize GBR techniques. Palabras clave: autogenous bone, guided bone regeneration, L-PRF bone-block, horizontal bone augmentation

Purpose: To clinically evaluate oral implant restorations placed by undergraduate students in the dental clinical curriculum at KU Leuven (Belgium) in terms of function and esthetics. Materials and methods: A retrospective observational cohort study was designed. The esthetic and functional evaluations of implant-supported restorations placed in the framework of the undergraduate implant dentistry clinical training program using White/Pink Esthetic Score (WES/PES) and visual analog scale (VAS) scoring was performed. Furthermore, complications were registered based retrospectively on the patient's medical file. The following research questions were stipulated: (1) How well do implant-supported restorations placed by undergraduate students perform esthetically? and (2) Which complications occurred and how were these managed? Results: Between August 2008 and July 2014 (6 academic terms), 251 implants (Brånemark System Mk III, Nobel Biocare) were placed in 113 patients by 155 students (> 40% of all students enrolled in the training program). Of these implants, 228 were restored in 101 patients by 118 students with varying restoration types. Esthetic scoring of the restorations in 83 of these patients revealed a satisfying mean WES of 8.14 ± 2.09 (out of 10) and PES of 9.56 ± 3.14 (out of 14). Complications were registered in 18.9% of the cases. Discussion: Clinical training in implant dentistry for undergraduates contributes to the development of advanced skills in the dental student's Master education. Overall, patients were satisfied with their implant-supported restorations. Implant and restoration success rates and complication incidence were confirmed by long-term data in the oral implant literature.

Purpose: To propose diffuse osteomyelitis as risk indicator for peri-implantitis following the loss of several dental implants in patients that present with highly sclerotic bone areas. Materials and Methods: A total of six “nightmare cases”—three of which were treated at the Department of Periodontology of the University Hospitals of the Catholic University Leuven and three of which were referred there for a second opinion—were retrospectively analyzed using radiographs obtained via contact with referring clinicians in order to fully reconstruct the treatment pathway and dental history for each of these patients. Results: All patients suffered from early implant failures and/or severe peri-implantitis with bone loss and crater formation up to the apical level, as well as the loss of all or nearly all implants. Re-examination of their preand postoperative CBCTs, in combination with several bone biopsies, confirmed the diagnosis of a diffuse sclerosing osteomyelitis in the treated area. Osteomyelitis could be linked to a longstanding history of chronic and/or therapyresistant periodontal/endodontic pathology. Conclusion: The current retrospective case series seems to suggest that diffuse osteomyelitis should be considered as a risk indicator for severe peri-implantitis. Palabras clave: bone quality, bone density, dental implants, implant failure, peri-implantitis

The aim of the present study was to compare leukocyte- and platelet-rich fibrin (L-PRF) membranes with a connective tissue graft (CTG) in combination with a coronally advanced flap (CAF) in the treatment of Miller Class I or II localized gingival recessions. A randomized controlled clinical trial with 17 recessions in each group was initiated; the control group received treatment with CAF+CTG, and the test group received CAF+L-PRF. The following variables were measured before treatment and after 1, 3, and 6 months: gingival recession depth (RD), gingival recession width (RW), gingival thickness (GT), probing depth (PD), clinical attachment level (CAL), and keratinized tissue height (KTH). Also, the root coverage percentage (RC), the pain score, postoperative complications, and the root coverage esthetic score (RES) were recorded after surgery. Both treatments presented significant improvements in the RD, RW, and CAL at 1, 3, and 6 months. CTG achieved a significantly higher RC at 1, 3, and 6 months and a significantly higher RES score at 6 months. L-PRF presented a significantly lower pain score and less postoperative complications. Both strategies were effective for the treatment of localized gingival recessions. The CTG obtained higher RC and esthetic results, and L-PRF had less pain and postsurgical complications.

Purpose: To clinically evaluate oral implant restorations placed by undergraduate students in the dental clinical curriculum at KU Leuven (Belgium) in terms of function and esthetics. Materials and methods: A retrospective observational cohort study was designed. The esthetic and functional evaluations of implant-supported restorations placed in the framework of the undergraduate implant dentistry clinical training program using White/Pink Esthetic Score (WES/PES) and visual analog scale (VAS) scoring was performed. Furthermore, complications were registered based retrospectively on the patient's medical file. The following research questions were stipulated: (1) How well do implant-supported restorations placed by undergraduate students perform esthetically? and (2) Which complications occurred and how were these managed? Results: Between August 2008 and July 2014 (6 academic terms), 251 implants (Brånemark System Mk III, Nobel Biocare) were placed in 113 patients by 155 students (> 40% of all students enrolled in the training program). Of these implants, 228 were restored in 101 patients by 118 students with varying restoration types. Esthetic scoring of the restorations in 83 of these patients revealed a satisfying mean WES of 8.14 ± 2.09 (out of 10) and PES of 9.56 ± 3.14 (out of 14). Complications were registered in 18.9% of the cases. Discussion: Clinical training in implant dentistry for undergraduates contributes to the development of advanced skills in the dental student's Master education. Overall, patients were satisfied with their implant-supported restorations. Implant and restoration success rates and complication incidence were confirmed by long-term data in the oral implant literature.

Purpose: To prospectively assess marginal bone loss and implant survival with Astra Tech (Dentsply Sirona, Charlotte, NC, USA) (group A) and Brånemark (Nobel Biocare, Zurich, Switzerland) (group B) implants in a split-mouth study conducted over a 20-year follow-up period. Materials and methods: A total of 95 implants (n = 50, group A and n = 45, group B) were randomly placed in the left or right side of the maxilla or mandible in 18 patients. Clinical and radiographic examinations were performed, and results were reported at 5, 10, 15 and 20 years after insertion of the prosthesis. Results: Ten patients were followed up for 20 years (n = 26 implants, group A and n = 25 implants, group B). No implant loss or prosthetic failures were observed. After 20 years of follow-up, no significant differences in marginal bone loss were found between both implant groups (P = 0.25). The proportion of marginal bone loss ≥ 0.5 mm was not significantly different between implant types (P > 0.05), and no statistically significant relationships were found between marginal bone loss and time (P ≥ 0.05). More specifically, there was no significant difference in marginal bone level between year 20 and baseline in group A (P = 0.70), whereas a difference of 0.5 to 1.0 mm was found in group B (P = 0.15). Conclusions: After 20 years of follow-up, marginal bone loss around screw-shaped titanium implants was clinically insignificant. Furthermore, no significant differences in survival and marginal bone loss were found between group A and B implants over the follow-up period. Palabras clave: bone remodelling, implant system, marginal bone level, osseointegration, split-mouth design Conflict-of-interest statement: The authors declare there are no conflicts of interest relating to this study.

Purpose: Sinus floor elevation (SFE) and simultaneous implant placement is predictable and reproducible. However, the graft material for the antral cavity remains a topic of debate. Considering the high osteogenic potential of the sinus membrane, most graft materials are generally accepted. This study aimed to assess the outcome of simultaneous SFE and implant placement, using leukocyte- and platelet-rich fibrin (L-PRF) as a sole graft material. Materials and Methods: This study was designed as a single cohort prospective study. Clinical and radiographic measurements (cone beam computed tomography [CBCT]) were performed immediately after implant placement and at abutment connection (6 months later). The amount of newly formed bone was linearly recorded on cross-sectional images. Four measurements (mesial, distal, buccal, palatal) were registered with the axis of the implant as reference. Results: Six lateral and 22 transalveolar SFEs were performed in 26 patients with simultaneous implant placement. Six months after surgery, 27/29 implants were clinically integrated. The mean vertical bone gain was 3.4 ± 1.2 mm and 5.4 ± 1.5 mm for transalveolar SFE and lateral SFE, respectively. The level of the new sinus floor was in all cases in continuation with the apex of the implant, and the peri-implant crestal bone height was stable. Conclusion: L-PRF as a sole graft material during simultaneous SFE and implant placement proved to be a practical, safe, and economical subsinus graft material, resulting in natural bone formation.

Purpose: The leukocyte- and platelet-rich fibrin block (L-PRF block) is a composite graft that combines a xenograft that is acting as a scaffold with L-PRF membranes that serve as a bioactive nodule with osteoinductive capacity. This study evaluated the properties of the L-PRF block and its components in terms of release of growth factors, cellular content, and structure. Materials and Methods: The concentration of transforming growth factor-β1 (TGF-β1), vascular endothelial growth factor (VEGF), platelet-derived growth factor-AB (PDGF-AB), and bone morphogenetic protein-1 (BMP-1) released by an L-PRF membrane and an L-PRF block were examined with ELISA for five time intervals (0 to 4 hours, 4 hours to 1 day, 1 to 3 days, 3 to 7 days, 7 to 14 days). Those levels in L-PRF exudate and liquid fibrinogen were also evaluated. The cellular content of the liquid fibrinogen, L-PRF membrane, and exudate was calculated. The L-PRF block was also analyzed by means of a microcomputed tomography (micro-CT) scan and scanning electron microscopy (SEM). Results: TGF-β1 was the most released growth factor after 14 days, followed by PDGF-AB, VEGF, and BMP-1. All L-PRF blocks constantly released the four growth factors up to 14 days. L-PRF membrane and liquid fibrinogen presented high concentrations of leukocytes and platelets. The micro-CT and SEM images revealed the bone substitute particles surrounded by platelets and leukocytes, embedded in a dense fibrin network. Conclusion: The L-PRF block consists of deproteinized bovine bone mineral particles surrounded by platelets and leukocytes, embedded in a fibrin network that releases growth factors up to 14 days. Palabras clave: blood platelets, cell count, fibrinogen, growth factors, scanning electron microscopy, tissue engineering