Peri-implant Bone Defects Research Articles

Bone tissue engineering in oral peri-implant defects in preclinical in vivo research: A systematic review and meta-analysis.

The regeneration and establishment of osseointegration within oral peri-implant bone defects remains a clinical challenge. Bone tissue engineering (BTE) is emerging as a promising alternative to autogenous and/or biomaterial-based bone grafting. The objective of this systematic review was to answer the focused question: in animal models, do cell-based BTE strategies enhance bone regeneration and/or implant osseointegration in experimental peri-implant defects, compared with grafting with autogenous bone or only biomaterial scaffolds? Electronic databases were searched for controlled animal studies reporting on peri-implant defects and implantation of mesenchymal stem cells (MSC) or other cells seeded on biomaterial scaffolds, following Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Random effects meta-analyses were performed for the outcomes histomorphometric bone area fraction (BA) and bone-to-implant contact (BIC). Nineteen studies reporting on large animal models (dogs and sheep) were included. Experimental defects were created surgically (16 studies) or via ligature-induced peri-implantitis (LIPI, three studies). In general, studies presented with an unclear to high risk of bias. In most studies, MSC were used in combination with alloplastic mineral phase or polymer scaffolds; no study directly compared cell-loaded scaffolds vs. autogenous bone. In three studies, cells were also modified by ex vivo gene transfer of osteoinductive factors. The meta-analyses indicated statistically significant benefits in favour of: (a) cell-loaded vs. cell-free scaffolds [weighted mean differences (WMD) of 10.73-12.30% BA and 11.77-15.15% BIC] in canine surgical defect and LIPI models; and (b) gene-modified vs. unmodified cells (WMD of 29.44% BA and 16.50% BIC) in canine LIPI models. Overall, heterogeneity in the meta-analyses was high (I2 70-88%); considerable variation was observed among studies regarding the nature of cells and scaffolds used. In summary, bone regeneration and osseointegration in peri-implant defects are enhanced by the addition of osteogenic cells to biomaterial scaffolds. Although the direction of treatment outcome is clearly in favour of BTE strategies, due to the limited magnitude of treatment effect observed, no conclusive statements regarding the clinical benefit of such procedures for oral indications can yet be made. Copyright © 2017 John Wiley & Sons, Ltd.

Repairing of peri-implant bone defects with dental pulp stem cells

Objective To establish an animal experimental model of immediately peri-implant bone defects in rabbit mandibular anterior teeth, and to investigate the osteogenetic capability of dental pulp stem cells (DPSCs) on bone defects around implant. Methods Eight rabbits were involved, whose bilateral mandibular anterior teeth were removed to form the bone defects with 2 mm × 3 mm area on the buccal side of tooth extraction sockets, and then the implants were implanted immediately. The rabbits were divided into two groups. The implants were Bio-oss with DPSCs and Bio-oss with phosphate buffer saline respectively for the experimental group and the control group. The bone regeneration in the defect region was evaluated by general observation, hematoxylin-eosin (HE) staining and Goldner trichrome staining and scanning electron microscope (SEM) at 4 weeks after implantation. Results The implantations were successfully conducted, and the implants were stable. There was no significant difference between the implants. The results of the HE staining and the trichrome staining showed that in the experimental group, new bone tissue and partial woven bone formed, and the properties of the newly formed bone cells were large, abundant, well differentiation, and arranging in woven pattern. While in the control group, the new bone-like tissue formation was less, and the mature cell differentiation was ordinary. The SEM results showed that there was a higher osteointegration between the new bone and the implant in the experimental group comparing with the control group. Conclusions The capability of Bio-oss with DPSCs is relatively superior to single Bio-oss in osteogenesis and osseointegration. Key words: Key words: Dental pulp stem cells; Bone defect; Immediately implant; Repair

The Mechanical Properties and Biometrical Effect of 3D Preformed Titanium Membrane for Guided Bone Regeneration on Alveolar Bone Defect.

The purpose of this study is to evaluate the effect of three-dimensional preformed titanium membrane (3D-PFTM) to enhance mechanical properties and ability of bone regeneration on the peri-implant bone defect. 3D-PFTMs by new mechanically compressive molding technology and manually shaped- (MS-) PFTMs by hand manipulation were applied in artificial peri-implant bone defect model for static compressive load test and cyclic fatigue load test. In 12 implants installed in the mandibular of three beagle dogs, six 3D-PFTMs, and six collagen membranes (CM) randomly were applied to 2.5 mm peri-implant buccal bone defect with particulate bone graft materials for guided bone regeneration (GBR). The 3D-PFTM group showed about 7.4 times higher mechanical stiffness and 5 times higher fatigue resistance than the MS-PFTM group. The levels of the new bone area (NBA, %), the bone-to-implant contact (BIC, %), distance from the new bone to the old bone (NB-OB, %), and distance from the osseointegration to the old bone (OI-OB, %) were significantly higher in the 3D-PFTM group than the CM group (p < .001). It was verified that the 3D-PFTM increased mechanical properties which were effective in supporting the space maintenance ability and stabilizing the particulate bone grafts, which led to highly efficient bone regeneration.

Peri-implant assessment via cone beam computed tomography and digital periapical radiography: an ex vivo study

OBJECTIVES:This research evaluated detail registration in peri-implant bone using two different cone beam computer tomography systems and a digital periapical radiograph.METHODS:Three different image acquisition protocols were established for each cone beam computer tomography apparatus, and three clinical situations were simulated in an ex vivo fresh pig mandible: buccal bone defect, peri-implant bone defect, and bone contact. Data were subjected to two analyses: quantitative and qualitative. The quantitative analyses involved a comparison of real specimen measures using a digital caliper in three regions of the preserved buccal bone – A, B and E (control group) – to cone beam computer tomography images obtained with different protocols (kp1, kp2, kp3, ip1, ip2, and ip3). In the qualitative analyses, the ability to register peri-implant details via tomography and digital periapical radiography was verified, as indicated by twelve evaluators. Data were analyzed with ANOVA and Tukey’s test (α=0.05).RESULTS:The quantitative assessment showed means statistically equal to those of the control group under the following conditions: buccal bone defect B and E with kp1 and ip1, peri-implant bone defect E with kp2 and kp3, and bone contact A with kp1, kp2, kp3, and ip2. Qualitatively, only bone contacts were significantly different among the assessments, and the p3 results differed from the p1 and p2 results. The other results were statistically equivalent.CONCLUSIONS:The registration of peri-implant details was influenced by the image acquisition protocol, although metal artifacts were produced in all situations. The evaluators preferred the Kodak 9000 3D cone beam computer tomography in most cases. The evaluators identified buccal bone defects better with cone beam computer tomography and identified peri-implant bone defects better with digital periapical radiography.

Effect of implant placement depth on the peri-implant bone defect configurations in ligature-induced peri-implantitis: An experimental study in dogs.

BackgroundThe subcrestal placement of implant platform has been considered a key factor in the preservation of crestal bone, but the influence of implant placement depth on bone remodeling combined with peri-implantitis is not fully understood. The aim of this study was to assess the effect of the crestal or subcrestal placement of implants on peri-implant bone defects of ligature-induced peri-implantitis in dogs.Material and MethodsEight weeks after tooth extraction in six beagle dogs, two different types of implants (A: OsseoSpeed™, Astra, Mölndal, Sweden; B: Integra-CP™, Bicon, Boston, USA) were placed at either crestal or subcrestal (-1.5 mm) positions on one side of the mandible. Ligature-induced peri-implantitis was initiated four weeks after the installation of the healing abutment connections. After 12 weeks, tissue biopsies were processed for histological analyses.ResultsSupra-alveolar bone loss combined with a shallow infrabony defect was observed in crestal level implants while deep and wide infrabony defects were present in subcrestal level groups. Subcrestal groups showed significantly greater ridge loss, depths and widths of infrabony defects when compared to crestal groups (P<0.001).ConclusionsWithin the limitations of the animal study, it can be stated that the implants at subcrestal position displayed greater infra-osseous defect than implants at crestal position under an experimental ligature-induced peri-implantitis. Key words:Subcrestal, peri-implantitis, histology.

Histological Evaluation of the Effect of Concentrated Growth Factor on Bone Healing.

The aim of this study was to evaluate the effects of concentrated growth factors (CGF) on the healing of peri-implant bone defects in an animal model. Twenty 4-month-old New Zealand White rabbits, each with an average weight of 3.5 kg, were used in this blinded, prospective, experimental study. Two implants were placed and 2 peri-impant defects were prepared in each rabbit tibia. Bone defects were created monocortically in the tibia of each rabbit using a trephine burr with a diameter of 8 mm. The implants were installed in each hole. The rabbits were divided into 4 groups: in group E, the defect was left empty; in group CGF, the defects were filled only with CGF; in group AB, the defects were filled with autogenous bone; and in group AB+CGF, the defects were filled with autogenous bone and CGF. The animals were euthanized at week 8 postimplantation. All implants from the 20 animals were fixed in 10% formalin and evaluated histomorphometrically. The mean defect area was highest in group E and lowest in group CGF+AB (P <0.05). The area of the defect differed significantly between groups AB and CGF+AB (P <0.05), but not between groups CGF and E. Implant-to-bone contact was lowest in group E. In the defect areas of groups CGF, AB and CGF+AB, a small amount of new bone formed around the implant. In this animal model of a peri-implant bone defect, restoration was achieved using a combination of autogenous bone and CGF. Further studies are needed to determine the behavior of CGF when used in the repair of bone defects in humans.

Effectiveness of enamel matrix derivative on the clinical and microbiological outcomes following surgical regenerative treatment of peri-implantitis. A randomized controlled trial.

This randomized clinical trial aimed at comparing radiological, clinical and microbial effects of surgical treatment of peri-implantitis alone or in combination with enamel matrix derivative (EMD). Twenty-six subjects were treated with open flap debridement and decontamination of the implant surfaces with gauze and saline preceding adjunctive EMD or no EMD. Bone level (BL) change was primary outcome and secondary outcomes were changes in pocket depth (PD), plaque, pus, bleeding and the microbiota of the peri-implant biofilm analyzed by the Human Oral Microbe Identification Microarray over a time period of 12months. In multivariate modelling, increased marginal BL at implant site was significantly associated with EMD, the number of osseous walls in the peri-implant bone defect and a Gram+/aerobic microbial flora, whereas reduced BL was associated with a Gram-/anaerobic microbial flora and presence of bleeding and pus, with a cross-validated predictive capacity (Q(2) ) of 36.4%. Similar, but statistically non-significant, trends were seen for BL, PD, plaque, pus and bleeding in univariate analysis. Adjunctive EMD to surgical treatment of peri-implantitis was associated with prevalence of Gram+/aerobic bacteria during the follow-up period and increased marginal BL 12months after treatment.

Histomorphometric Evaluation of Bone Formation in Peri-Implant Defects Treated With Different Regeneration Techniques: An Experimental Study in a Rabbit Model

The aim of this study was to investigate the healing of artificially created peri-implant circumferential bone defects using three bone-regeneration techniques. Rabbit tibias (24 rabbits), in which bone defects (9-mm diameter, 4-mm depth) were created and implant beds (3-mm diameter, 6-mm depth) were prepared in the middle of the created defects, were used as the experimental model. Dental implants (3.0 × 10mm) were inserted, and the peri-implant bone defects were grafted with demineralized freeze-dried bone allograft (DFDBA) plus saline solution, DFDBA plus platelet-rich fibrin (PRF), or DFDBA plus rifamycin. After 4weeks, the animals were euthanized and the implants with surrounding bone were removed. Undecalcified histomorphometric examinations with toluidine blue staining were performed, and the bone-to-implant contact (BIC) and percentage of new bone formation were evaluated. The BIC was 50.94% ± 24.39% in the DFDBA-plus-saline solution group, 60.07% ± 4.91% in the DFDBA-plus-rifamycin group, and 73.43% ± 3.86% in the DFDBA-plus-PRF group. The percentage of new bone formation at the defect area was 37.61% ± 1.70% in the DFDBA-plus-saline solution group, 48.51% ± 2.80% in the DFDBA-plus-rifamycin group, and 63.09% ± 2.10% in the DFDBA-plus-PRF group. In terms of new bone formation and BIC, the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups were significantly different from the DFDBA-plus-saline solution group. The difference between the DFDBA-plus-PRF and DFDBA-plus-rifamycin groups was also statistically significant. The addition of PRF or rifamycin to DFDBA had a significant positive effect on bone healing in peri-implant bone defects. The DFDBA-plus-PRF group showed the highest percentages of new bone formation and BIC.

Peri-implant defect regeneration in the diabetic pig: Apreclinicalstudy.

The study aims to establish a peri-implant dehiscence-type bone defect in a diabetic animal model of human bone repair and to quantify the influence of diabetes on peri-implant bone regeneration. Experimental diabetes was induced in three domestic pigs by streptozotocin. Three animals served as healthy controls. After 12 months four standardized peri-implant dehiscence bone defects were surgically created in the ramus mandibulae. The animals were sacrificed after 90 days. Samples were histologically analyzed to quantify new bone height (NBH), bone-to-implant-contact (BIC), area of newly formed bone (NFB), bone-density (BD), and bone mineralization (BM) in the prepared defect (-D) and in a local control region (-L). After 90 days, diabetic animals revealed a significantly lower BIC (p=0.037) and BD (p=0.041) in the defect area (-D). NBH and BM-D differences within the groups were not significant (p>0.05). Significant more NFB was measured in the healthy control group (p=0.046). In the region of local bone BIC-L was significant less in the diabetic group (p=0.028). In the local control region BD-L and BM-L was lower in the diabetic group compared to the healthy control animals (p>0.05). Histological evidence indicates impaired peri-implant defect regeneration in a diabetic animal model.

Influence of wound closure on the volume stability of particulate and non-particulate GBR materials: an invitro cone-beam computed tomographic examination. Part II.

To test whether GBR with an L-shaped soft-block bone substitute and particulate bone substitute differs from GBR with particulate bone substitute as regards the volume stability of the augmented region during flap closure. Twenty peri-implant box-shaped bone defects were created in 10 pig mandibles. Every bone defect was augmented with each of the following two GBR procedures in turn: control group - particulate xenograft applied buccally + collagen membrane + pins; test group - particulate xenograft applied buccally + L-shaped soft-block xenograft applied buccally and occlusally + collagen membrane + pins. Cone-beam computed tomography scans were obtained before and after wound closure. The horizontal thickness (HT) of the augmented region (bone substitute + membrane) was assessed at the implant shoulder (HT0mm ) and at 1mm to 5mm apical to the implant shoulder (HT1mm -HT5mm ). In the test group, the vertical thickness (VT) and 45° thickness (45-T) of the augmented region were measured from the implant shoulder. The changes in HT during flap suturing were calculated as absolute (mm) and relative values (%). Repeated-measures ANOVAs were used for statistical analysis. The reduction in HT0mm was 20.5±23.3% (SD) in the control group and 2.4±9.2% (SD) in the test group (P=0.014). There were no statistically significant differences in changes in HT1-5mm between the groups (P>0.05). In the test group, the reduction in VT amounted to 28.0±11.9% (SD) and the reduction in 45-T amounted to 24.8±10.2% (SD) (P<0.001). The addition of an L-shaped soft-block bone substitute to a particulate xenograft, covered by a collagen membrane and fixed with pins, significantly improved the horizontal volume stability of the augmented region during wound closure.

The healing effect of platelet-rich plasma on xenograft in peri-implant bone defects in rabbits.

BackgroundThe association of biomaterial combined with repair factor-like platelet-rich plasma (PRP) has prospective values. Bovine-derived xenograft has been identified as an osteoconductive and biocompatible grafting material that provides osseointegration ability. PRP has become a valuable adjunctive agent to promote healing in a lot of dental and oral surgery procedures. However, there are controversies with respect to the regenerative capacity of PRP and the real benefits of its use in bone grafts. The purpose of this study was to assess the influence of PRP combined with xenograft for the repair of peri-implant bone defects.MethodsTwelve rabbits were used in this study, and the experimental surgery with implant installation was performed simultaneously. Autologous PRP was prepared before the surgical procedure. An intrabony defect (7.0 mm in diameter and 3.0 mm deep) was created in the tibia of each rabbit; then, 24 titanium dental implants (3.0 mm in diameter and 8.5 mm long) were inserted into these osteotomy sites. Thus, a standardized gap (4.0 mm) was established between the surrounding bony walls and the implant surface. The gaps were treated with either xenograft alone (control group) or xenograft combined with PRP (experimental group). After healing for 1, 2, 3, 4, 5, and 6 weeks, the rabbits were sacrificed with an overdose of KCl solution. Two rabbits were killed at each time, and the samples including dental implants and surrounding bone were collected and processed for histological analysis.ResultsMore newly formed bone and a better bone healing process were observed in control group. The histomorphometric analysis revealed that the mean percentage of bone-to-implant contact in the control group was significantly higher than that of the experimental group (25.23 vs. 8.16 %; P < 0.05, independent-simple t test, analysis of variance [ANOVA]).ConclusionsThe results indicate that in the addition of PRP to bovine-derived xenograft in the repair of bone defects around the implant, PRP may delay peri-implant bone healing.

Efficacy of stem cells on the healing of peri-implant defects: systematic review of preclinical studies.

This systematic review considers the evidence from animal studies evaluating the effectiveness of mesenchymal stem cells (MSC) in the treatment of intraoral peri‐implant defects. MEDLINE, EMBASE, and LILACS databases were searched for quantitative preclinical controlled animal model studies that evaluated the effect of MSC on bone healing at intraoral peri‐implant bone defects. The primary outcome was the amount of (re‐)osseointegration reported as bone‐to‐implant contact in the defect area. The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses statement guidelines. Ten studies met the inclusion criteria. Only one study induced peri‐implant inflammation to produce peri‐implant bone defects. In all others, defects were surgically created at implant installation. Differences in defect morphology were identified among the studies. Both xenogenous and autogenous MSC were used to treat peri‐implant defects. These included bone marrow‐derived MSC, periodontal ligament‐derived MSC, umbilical cord MSC, bone marrow‐derived mononuclear cells, and peripheral blood mononuclear cells. Meta‐analysis was not possible because of heterogeneities in study designs. Nonetheless, in most studies, local MSC implantation was not associated with adverse effects and had a positive effect on bone healing around peri‐implant defects. Combination of MSC with membranes and bioactive factors appears to provide improved treatment outcomes. In large animal models, intraoral use of MSC may provide beneficial effects on bone healing within peri‐implant defects. The various degrees of success of MSC in peri‐implant bone healing are likely to be related to the use of cells from various populations, tissues, and donor species. However, human safety and efficacy must be demonstrated before its clinical use can be considered.

Peri-implant bone loss clinical and radiographic evaluation around rough neck and microthread implants: a 5-year study.

To evaluate marginal bone loss over 5years around microthreaded implants placed in the maxillary anterior/esthetic zone and immediate restored with non-occlusal loading. Seventy-one implants (with microthreads up to the platform-rough surface body and neck, internal connection and platform switching) were placed in healed bone in the maxillary arches of 30 men and 23 women (mean age 37.85±7.09years, range 27-60). All subjects had at least 3mm of soft tissue to allow the establishment of adequate biologic width and to reduce bone resorption. Each patient received a provisional restoration immediately after implant placement with slight occlusal contact. Mesial and distal bone height was evaluated using digital radiography on the day following implant placement (baseline) and after 1, 2, 3, 4 and 5years. Primary stability was measured with resonance frequency analysis. No implants failed, resulting in a cumulative survival rate of 100% after 3years. Marginal bone loss from implant collar to bone crest measured at baseline (peri-implant bone defect at the fresh extraction socket) and after 5years was 0.90mm±0.26mm. Mesial and distal site crestal bone loss ranged from 3.42±1.2mm at baseline to 3.51±1.5mm after 5years and from 3.38±0.9mm at baseline to 3.49±0.9mm after 5years, respectively (P=0.086). The results of this study showed limited implant crestal bone loss 0.90mm±0.26mm and 100% of implant survival rate at 5-year follow-up of immediate restored implants with rough surface neck and microthreads.

Periimplant bone regeneration in hydroxyapatite block grafts with mesenchymal stem cells and bone morphogenetic protein-2.

Hydroxyapatite (HA) blocks as an alternative material for autogenous onlay bone grafts are regarded as an insufficient substitute for osseointegration of dental implant. In this study, we evaluated the effects of dog mesenchymal stromal cells (dMSCs) with or without bone morphogenetic protein-2 (BMP) on new peri-implant bone formation after HA block graft. In four mandibular bone defects (8×8×6 mm each) in five beagle dogs, dental implants were placed with HA block loaded with autogenous dMSCs with or without BMP-2. Animals were sacrificed at eight weeks, and bone healing was evaluated among four groups consisting of 1) HA alone as a control, 2) HA+dMSCs, 3) HA+BMP-2, and 4) HA+dMSCs+BMP-2. According to histomorphometric evaluation, the MSC+BMP-2 group and the BMP-2 group showed significantly higher bone-implant-contact (BIC) length than the MSC group, while there was no significant difference in new bone formation among the groups. According to micro-CT analysis, bone volume and bone mineral density were significantly higher in the MSC+BMP-2 group compared with the control group (p<0.01 and p<0.05, respectively). BIC was significantly higher in the MSC+BMP-2 group than both the control and MSC groups (p<0.01 and p<0.05, respectively). In conclusion, our results showed that bone regeneration at peri-implant bone defects grafted with HA blocks was significantly increased by dual delivery of MSCs and BMP-2. Conversely, HA blocks with MSC or BMP-2 alone did not allow for efficient peri-implant bone regeneration.

RELATIONSHIP OF TWO FACTORS AFFECTING OSSEOINTEGRATION OF IMMEDIATE IMPLANT

Background: Implant stability plays important role in the success of implant which is affected by peri-implant bone defect .Also the bone formation around the implant indicates the implant os- seointegration condition. Aim of the study: was aimed to evaluate the relation between horizontal gap ,implant stability and osseointegration of immediate implant. Patient & Methods: This study included 14 patients (8males and 6 females) average age was 32 years. 20 implants were inserted into 20 fresh extracted of maxillary non restorable single rooted teeth. Horizontal gap was measured immediately after implant insertion, stability and bone density of each implant were measured immediately, 3 and 6months postoperatively. All data were ana- lyzed statistically. Results: The mean of horizontal gap was 1.84±0.38, implant stability measures were 58.35±4.53, 64.9±2.63 and 74.45±4.78 while bone density were 1303.2±140.68, 1609.15±122.84 and 1963.25±127.13 immediately,3 & 6 months postoperatively respectively. Horizontal gap re- sults statistically showed reverse relation with implant stability & bone density results. While im- plant stability results showed direct relation with bone density results. Conclusion: Horizontal gap has reverse relation with implant stability & osseointegration. While implant stability has direct relation with osseointegration.

Evaluation of bone substitutes for treatment of peri-implant bone defects: biomechanical, histological, and immunohistochemical analyses in the rabbit tibia.

PurposeWe sought to evaluate the effectiveness of bone substitutes in circumferential peri-implant defects created in the rabbit tibia.MethodsThirty rabbits received 45 implants in their left and right tibia. A circumferential bone defect (6.1 mm in diameter/4 mm depth) was created in each rabbit tibia using a trephine bur. A dental implant (4.1 mm × 8.5 mm) was installed after the creation of the defect, providing a 2-mm gap. The bone defect gaps between the implant and the bone were randomly filled according to the following groups: blood clot (CO), particulate Bio-Oss® (BI), and Bio-Oss® Collagen (BC). Ten animals were euthanized after periods of 15, 30, and 60 days. Biomechanical analysis by means of the removal torque of the implants, as well as histologic and immunohistochemical analyses for protein expression of osteocalcin (OC), Runx2, OPG, RANKL, and TRAP were evaluated.ResultsFor biomechanics, BC showed a better biological response (61.00±15.28 Ncm) than CO (31.60±14.38 Ncm) at 30 days. Immunohistochemical analysis showed significantly different OC expression in CO and BC at 15 days, and also between the CO and BI groups, and between the CO and BC groups at 60 days. After 15 days, Runx2 expression was significantly different in the BI group compared to the CO and BC groups. RANKL expression was significantly different in the BI and CO groups and between the BI and BC groups at 15 days, and also between the BI and CO groups at 60 days. OPG expression was significantly higher at 60 days postoperatively in the BI group than the CO group.ConclusionsCollectively, our data indicate that, compared to CO and BI, BC offered better bone healing, which was characterized by greater RUNX2, OC, and OPG immunolabeling, and required greater reversal torque for implant removal. Indeed, along with BI, BC presents promising biomechanical and biological properties supporting its possible use in osteoconductive grafts for filling peri-implant gaps.

Treatment of Peri-Implant Defects in the Rabbit's Tibia with Adipose or Bone Marrow-Derived Mesenchymal Stems Cells.

Mesenchymal stem cell (MSC) treatment in conjunction with bone graft materials or space filler can be an alternative to autogenous bone grafts in the treatment of peri-implant bone defects. To evaluate the success of bone regeneration capacity of adipose-derived and bone marrow-derived MSCs for the treatment of peri-implant bone defects when applied with a beta-tricalcium phosphate/collagen-based scaffold. Forty implants were placed into the tibiae of 10 rabbits bilaterally. Surgical defects created around the implants were treated with one the following treatment modalities: 1) adipose-derived MSC transplanted scaffold + collagen membrane; 2) bone marrow-derived MSC transplanted scaffold + collagen membrane; 3) autogenous bone + collagen membrane; and 4) collagen membrane only. The bone regeneration capacity of each technique was determined by histomorphometry, micro-CT, and measuring the implant stability by resonance frequency analysis. One limb of one rabbit was excluded because of fracture, and another limb was excluded because of infection. All parameters on 36 implants revealed that both sources of MSC can form equivalently new bone that is comparable with autogenous bone. The defects treated with membrane only had significantly less bone formation compared with other groups. Both adipose-derived and bone marrow-derived MSC treatments are feasible alternatives to autogenous bone grafts in the treatment of peri-implant osseos defects.

Detection of peri‐implant bone defects with different radiographic techniques – a human cadaver study

Two- and three-dimensional radiographic techniques are available to determine peri-implantitis-related bone loss around dental implants. To compare the performance of detecting different peri-implant bone defects in intraoral radiography (IR), panoramic radiography (PR), Cone Beam Computer Tomography (CBCT) and Computer Tomography (CT). Six implants were inserted under ideal conditions into the lower jaw of an edentulous human cadaver. IR, PR, CBCT and CT were performed. Two-wall, three-wall and four-wall defects with 1 mm depth were artificially created around two of the implants (one anterior and one posterior), and radiographies were repeated. The identical set-up was used for 3-mm-deep bone defects. All images were presented to seven observers. Sensitivity (SN) and specificity (SP) were determined for each modality, defect type and depths, and likelihood ratios were calculated. The highest sensitivity was found with IR and CBCT for 1 mm (0.67; 0.68) and 3-mm defects (0.81; 0.79). The highest specificity was found with IR for both defect depths (0.51). The best classification of defect type revealed PR for both 1-mm and 3-mm-deep defects. Both likelihood ratios (LR+ and LR-) were best for IR with 1-mm (1.37 and 0.65) and with 3-mm defects (1.65 and 0.37). IR should still be recommended as favourable method evaluating bone loss around dental implants, while CT demonstrated the lowest performance in detecting peri-implant bone defects.

Treatment of Peri-implant Bone Defects with Platelet-Rich Fibrin.

The objective of this study was to investigate and compare the clinical effectiveness of the application of platelet-rich fibrin (PRF) and conventional flap surgery for the treatment of peri-implant bone loss. Nineteen patients (8 women, 11 men) with peri-implant bone loss were randomly allocated to two groups, with the PRF group comprising patients who received fibrin scaffold and the control group made up of those who received only the access flap. At 3 and 6 months after surgery, respectively, the PRF group demonstrated higher mean probing depth reductions (2.41 ± 1.06 and 2.82 ± 1.03 mm versus 1.65 ± 1.02 and 2.05 ± 0.77 mm) and more gains in clinical attachment level (2.89 ± 1.01 and 3.31 ± 1.08 mm versus 1.43 ± 1.08 and 1.84 ± 0.81 mm) compared with the control group. In addition, the increase in the amount of keratinized mucosa from baseline to 6 months postoperatively was statistically significant for the PRF group (P < .001). Hence, the data from the current study led to the conclusion that PRF application in periimplant bone loss provided better clinical results than conventional flap surgery.

Effect of field of view in the detection of chemically created peri-implant bone defects in bovine ribs using cone beam computed tomography: an in vitro study

To assess the accuracy of cone beam computed tomography (CBCT) using two fields of view (FOVs) in the diagnosis of peri-implant defects. Eighty implants were placed in bovine ribs, in which peri-implant bone defects of two sizes (T1 and T2) were simulated using 70% perchloric acid. CBCT images were acquired with the use of two FOV size settings of the i-CAT NG unit: 6 × 16 cm and 8 × 8 cm. One oral and maxillofacial surgeon (OMS) and two oral and maxillofacial radiologists (OMRs) evaluated the presence of defects, and their findings were compared with direct visual evaluation. The kappa (κ)-statistic, area under the curve (AUC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the examinations were calculated. AUC values were compared with the Student t test. The obtained κ-values indicated good intra- and interobserver agreement. A significant difference was found between T1 and T2 (P = .01) with regard to AUC values, and no significant difference was found between the different FOVs in both test groups (T1, P = .06; T2, P = .33). The sensitivity, specificity, PPV, and NPV of the examinations were higher for the OMRs than for the OMS involved in the study. The ability of CBCT to detect chemically created peri-implant bone defects was good, especially for larger defects (Group T2) but only for the observations of the OMRs. The observations of the OMS were less accurate. The two FOVs tested were appropriate to detect peri-implant bone defects.