Oral implants placed in bone defects treated with Bio‐Oss®, Ostim®‐Paste or PerioGlas: an experimental study in the rabbit tibiae

Objectives: To compare the histological features of bone filled with Bio‐Oss^®, Ostim‐Paste^® or PerioGlas placed in defects in the rabbit tibiae by evaluating bone tissue composition and the integration of titanium implants placed in the grafted bone. Material and methods: Two cylindrical bone defects, about 4 mm in diameter and 6 mm in depth, were created in the tibiae of 10 rabbits. The defects were filled with either Bio‐Oss^®, PerioGlas, Ostim^®‐Paste or left untreated, and covered with a collagen membrane. Six weeks later, one titanium sandblasted and acid‐etched (SLA) implant was inserted at the centre of each previously created defect. The animals were sacrificed after 6 weeks of healing. Results: Implants placed in bone previously grafted with Bio‐Oss^®, PerioGlas or Ostim^®‐Paste obtained a larger extent of osseointegration, although not statistically significant, than implants placed in non‐grafted bone. The three grafting materials seemed to perform in a similar way concerning their contribution towards implant osseointegration. All grafting materials appeared to be osteoconductive, thus leading to the formation of bridges of mineralized bone extending from the cortical plate towards the implants surface through the graft scaffold. Conclusions: Grafting with the above‐mentioned biomaterials did not add any advantage to the osseointegration of titanium SLA implants in a self‐contained defect.     

Influence of low-level laser treatment on bone regeneration and osseointegration of dental implants following sinus augmentation. An experimental study on sheep

Objectives: The aim of this experimental study was to evaluate if low‐level laser treatment (LLLT) enhances bone regeneration and osseointegration of dental implants in a sinus graft model. Material and methods: Twelve sheep underwent a bilateral sinus floor elevation procedure with cancellous bone from the iliac crest. Implant insertion followed 4 weeks (six sheep) and 12 weeks (six sheep) later. Sixteen weeks after second‐stage surgery, animals were sacrificed. Unilaterally, the grafted sinus and during the second‐stage surgery the implant sites were irradiated intraoperatively and three times during the first postoperative week with a diode laser (75 mW, 680 nm). The overall energy density per irradiation was 3–4 J/cm². Biopsies of the augmented area were obtained during implant insertion and after scarification. Results: Bone regeneration within the grafted sinus histomorphometric analysis hardly differed between control and test side both 4 and 12 weeks after sinus grafting. Osseointegration measurements resulted in a significantly higher bone/implant contact (BIC) on the test side (P=0.045). Further evaluation of peri‐implant bone tends to amount in significant higher percentage on the laser side (P=0.053). Conclusion: The presented experimental study on sheep did not confirm a positive LLLT effect on bone regeneration within a cancellous sinus graft. Nevertheless, LLLT possibly has a positive effect on osseointegration of dental implants inserted after sinus augmentation.     

Implant Osseointegration in Circumferential Bone Defects Treated with Latex‐Derived Proteins or Autogenous Bone in Dog's Mandible

Background: In sites with diminished bone volume, the osseointegration of dental implants can be compromised. Innovative biomaterials have been developed to aid successful osseointegration outcomes. Purpose: The aim of this study was to evaluate the osteogenic potential of angiogenic latex proteins for improved bone formation and osseointegration of dental implants. Materials and Methods: Ten dogs were submitted to bilateral circumferential defects (5.0 × 6.3 mm) in the mandible. Dental implant (3.3 × 10.0 mm, TiUnite MK3?, Nobel Biocare AB, Göteborg, Sweden) was installed in the center of the defects. The gap was filled either with coagulum (Cg), autogenous bone graft (BG), or latex angiogenic proteins pool (LPP). Five animals were sacrificed after 4 weeks and 12 weeks, respectively. Implant stability was evaluated using resonance frequency analysis (Osstell Mentor?, Osstell AB, Göteborg, Sweden), and bone formation was analyzed by histological and histometric analysis. Results: LPP showed bone regeneration similar to BG and Cg at 4 weeks and 12 weeks, respectively (p ≥ .05). Bone formation, osseointegration, and implant stability improved significantly from 4 to 12 weeks (p ≤ .05). Conclusion: Based on methodological limitations of this study, Cg alone delivers higher bone formation in the defect as compared with BG at 12 weeks; compared with Cg and BG, the treatment with LPP exhibits no advantage in terms of osteogenic potential in this experimental model, although overall osseointegration was not affected by the treatments employed in this study.     

Resolution of surgically created three‐wall intrabony defects in implants using three different biomaterials: an in vivo study

Objectives: To histomorphometrically analyze bone formation on amorphous calcium phosphate (ACP), micro‐macroporous biphasic calcium phosphate (MBCP), and freeze‐dried bone allograft (FDBA) in three‐wall defects adjacent to structured surface with calcium phosphate nanocoating implants in dogs. Materials and methods: Five male mixed‐breed dogs were used in this study. The premolars and molars were extracted on both sides of the mandible. Eight weeks after extraction, four implants were submerged on each side of the mandible. Three‐wall intrabony defects (5 × 3 × 3 mm) were surgically created adjacent to the implants before installation. No grafts were placed in the control group. At the experimental sites, each intrabony defect was grafted with either ACP, MBCP, or FDBA. The dogs were sacrificed after 12 weeks, and histological and histomorphometrical analyses of the implant sites were performed. Results: All of the three experimental groups exhibited defect resolution and osseointegration that showed a statistically significant difference compared with the control group in terms of remaining defect depth and bone‐to‐implant contact (BIC). However, there were no statistical significances among the three experimental groups. MBCP had the highest BIC (63.57 ± 21.57%), followed by ACP and FDBA. The control group showed the least bone area and the greatest remaining defect depth. Conclusion: Grafts with the synthetic biomaterials ACP and MBCP showed bone regeneration that was similar to FDBA in surgically created three‐wall intrabony defects adjacent to implants. Within the limitations of this study, it can be concluded that ACP and MBCP synthetic biomaterials are as effective as FDBA at osteoconduction. To cite this article:
Choi J‐Y, Jung U‐W, Lee I‐S, Kim C‐S, Lee Y‐K, Choi S‐H. Resolution of surgically created three‐wall intrabony defects in implants using three different biomaterials: an in vivo study.
Clin. Oral Impl. Res 22 , 2011; 343–348.
doi: 10.1111/j.1600‐0501.2010.01978.x     

Effect of local zoledronate delivery on osseointegration: a systematic review of preclinical studies

Purpose: The aim of the present systematic review was to assess the effect of local zoledronate (ZOL) delivery (topical or as implant surface coatings) on osseointegration.

Materials and methods: In this systematic review, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed. To address the focused question, ‘Does local zoledronate delivery enhance osseointegration?’ indexed databases were searched without time or language restrictions up to and including April 2017 using various combination of the following keywords: ‘zoledronate’, ‘bisphosphonates’, ‘osseointegration’ and ‘topical administration’. Letters to the Editor, historic reviews, commentaries, case-series and case-reports were excluded.

Results: Initially, 383 articles were identified out of which, 23 experimental studies fulfilled the inclusion criteria. In 18 studies, ZOL was incorporated into implants surfaces as a coating and in five studies ZOL was applied topically (bone graft or irrigation) into the bone cavities. Results from 87% studies reported that local delivery of ZOL (coating or topical) is effective in enhancing osseointegration or new bone formation around implants.

Conclusions: Local ZOL delivery (coating or topical) seems to enhance osseointegration in animals; however, from a clinical perspective, further randomized control trials with long-term follow-up are needed in this regard.     

Microcomputed tomographic analysis of bone microarchitecture after sinus augmentation with hyaluronic matrix: a case–control study

Background

The aim of this study was to analyze trabecular microarchitecture of augmented sinuses with hyaluronic matrix and xenograft by microcomputed tomography, and to investigate whether hyaluronic matrix has an effect on the newly formed bone quality.

Materials and methods

Thirteen patients undergoing maxillary sinus augmentation were included in this split-mouth study. Right and left sinus sites were randomly assigned to test and control group. In test group, the sinus was grafted with hyaluronic matrix and xenograft; in control group, only with xenograft. Four months after augmentation, bone samples were harvested during implant placement and analyzed for the following trabecular microarchitecture parameters using microcomputed tomography: bone volume (BV), total volume (TV), bone volume fraction (BV/TV), bone surface (BS), specific bone surface (BS/BV), bone surface density (BS/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), trabecular pattern factor (Tb.Pf), and fractal dimension (FD).

Results

There was statistically significant difference only for BS/TV parameter between two groups. BS/TV was higher in hyaluronic matrix group compared with control group.

Conclusions

Addition of hyaluronic matrix to xenograft may enhance bone quality in terms of bone surface density. However, more research investigating the microstructural variation of augmented sinuses is needed with a greater sample.

     

Bone replacement grafts with guided tissue regeneration in treatment of grade II furcation defects: a systematic review and meta-analysis

Aim

The present systematic review appended with meta-analysis aimed to evaluate the efficacy of bone replacement graft (BRG) with guided tissue regeneration (GTR) over BRG or open flap debridement (OFD) alone in the treatment of grade II furcation defects.

Materials and methods

An electronic literature search of PubMed, Cochrane Library and Google Scholar databases accompanied with manual searching was done. Randomized controlled trials (RCTs) up to October 2019, comparing BRG+GTR with BRG or OFD in grade II furcation defects, were identified. Clinical attachment level (CAL) gain, changes in gingival marginal level (GML), vertical defect fill (VDF), horizontal defect fill (HDF) and reduction in defect volume were the outcome parameters.

Results

Of a total of 12, 9 studies compared BRG+GTR vs BRG while 3 compared BRG+GTR vs OFD. Meta-analysis was carried out for CAL gain, VDF, HDF and GML changes. In the BRG+GTR vs BRG comparison group, out of 9 studies, 6 RCTs showed standardized mean difference (SMD) of 0.513 for VDF, 9 RCTs showed SMD of 0.83 for HDF and 2 RCTs showed SMD of 0.651 for CAL gain, whereas only 2 studies in the same group reported reduction in defect volume. Three studies of the BRG+GTR vs OFD group exhibited significant VDF and CAL gain with SMD of 2.002 and 1.161 respectively. However, no significant change was recorded for GML in both groups.

Conclusion

The present systematic review indicates supplemental benefits of combination therapy of BRG+GTR over monotherapy in resolving grade II furcation defects.

Clinical relevance

In our quest to achieve maximum regeneration in grade II furcation defects, combination therapies such as BRG+GTR have been accepted as treatment choices over other modalities. Clinical situations warranting near-complete regeneration of the tissues in such defects are better suited for combination therapies.

     

Sinus graft with biogran, autogenous bone, and PRP: a report of three cases with histology and micro-CT

Three sinuses were grafted with a bioactive glass bone substitute (Biogran) mixed with autogenous bone retrieved from intraoral donor sites. In two of the three sinuses a platelet-rich plasma (PRP) gel was added to the graft. Bone biopsies retrieved after 5, 6, and 15 months were analyzed. Micro-computerized tomography (micro-CT) values of total bone volume/total volume (TBV/TV) were very reliable compared to histomorphometry. Biogran mixed with autogenous bone and PRP seems to have a positive effect in sinus grafting, with TBV/TV values ranging between 40% and 68%. Micro-CT results have never been compared with histomorphometry for the evaluation of grafted biomaterials. Micro-CT evaluation of some morphometric parameters was difficult, because the radiodensities of Biogran and a certain grade of bone mineralization were similar.     

Surface Roughness of Dental Implant and Osseointegration

IntroductionDental implants are a usual treatment for the loss of teeth. The success of this therapy is due to the predictability, safety and longevity of the bone–implant interface. Dental implant surface characteristics like roughness, chemical constitution, and mechanical factors can contribute to the early osseointegration. The aim of the present article is to perform a review of the literature on surface roughness of dental implant and osseointegration.MethodologyThis work is a narrative review of some aspects of surface roughness of dental implant and osseointegration.ConclusionDespite technological advancement in the biomaterials field, the ideal surface roughness for osseointegration still remains unclear. In this study about surface nanoroughness of dental implant and osseointegration, the clinical relevance is yet unknown. Innovative findings on nanoroughness are valuable in the fields of dental implantology, maxillofacial or orthopedic implant surfaces and also on cardiovascular implants in permanent contact with patient’s blood.     

The role of Vitamin D as an adjunct for bone regeneration: A systematic review of literature

Background and objectivesIn spite of bone’s healing capacity, critical-size bone defect regeneration and peri-implant osseointegration are challenging. Tissue engineering provides better outcomes, but requires expensive adjuncts like stem cells, growth factors and bone morphogenic proteins. Vitamin D (Vit.D) regulates calcium and phosphorus metabolism, and helps maintain bone health. Vit.D supplements in deficient patients, accentuates bone healing and regeneration. Therefore the aim of this systematic review was to evaluate the role of adjunctive Vit.D on bone defect regeneration.MethodsComprehensive database search of indexed literature, published between January 1990 and June 2022, was carried out. English language articles fulfilling inclusion criteria (clinical/in vivo studies evaluating bone regeneration including osseointegration and in vitro studies assessing osteogenic differentiation, with adjunct Vit.D) were identified and screened.ResultsDatabase search identified 384 titles. After sequential title, abstract and full-text screening, 23 studies (in vitro – 9/in vivo – 14) were selected for review. Vit.D as an adjunct with stem cells and osteoblasts resulted in enhanced osteogenic differentiation and upregulation of genes coding for bone matrix proteins and alkaline phosphatase. When used in vivo, Vit.D resulted in early and increased new bone formation and mineralization within osseous defects, and better bone implant contact and osseointegration, around implants. Adjunct Vit.D in animals with induced systemic illnesses resulted in bone defect regeneration and osseointegration comparable to healthy animals. While systemic and local administration of Vit.D resulted in enhanced bone defect healing, outcomes were superior with systemic route.ConclusionsBased on this review, adjunct Vit.D enhances bone defect regeneration and osseointegration. In vitro application of Vit.D to stem cells and osteoblasts enhances osteogenic differentiation. Vit.D is a potentially non-invasive and inexpensive adjunct for clinical bone regeneration and osseointegration. Long term clinical trials are recommended to establish protocols relating to type, dosage, frequency, duration and route of administration.     

Ozone Therapy Enhances Osseous Healing in Rats With Diabetes With Calvarial Defects: A Morphometric and Immunohistochemical Study

Background: Bone healing is impaired in diabetes mellitus (DM) cases. The aim of this study is to investigate, both morphometrically and immunohistochemically, the effect of gaseous ozone on bone healing in diabetic rat calvarial defects treated with xenografts. Methods: DM was induced with 50 mg/kg intraperitoneal streptozotocin in 56 male Wistar rats. Study groups were as follows: 1) empty defect (control, n = 14); 2) xenograft (XG, n = 14); 3) empty defect treated with ozone therapy (control + ozone, n = 14); and 4) xenograft and ozone application (XG + ozone, n = 14). Critical‐size defects were created in all rats. Bovine‐derived xenograft was applied to XG groups. Gaseous ozone was applied on the operation day and daily for 2 weeks (140 ppm at 2 L/d, 2.24 mg). Rats were sacrificed at 4 or 8 weeks post‐surgery. Total bone area, newly formed bone, and residual graft material were measured histomorphometrically. Osteocalcin and bone morphogenic protein (BMP)‐2 expression was evaluated immunohistochemically. Results: Osteoclast numbers in the XG + ozone group were higher than the other groups at week 4 (P <0.05). XG + ozone group revealed more total bone area and new bone area than the XG group at weeks 4 (P <0.05) and 8 (P >0.05). Residual graft materials were decreased in the XG + ozone group and the same group revealed more BMP‐2 positivity compared with other groups. Osteocalcin positivity in XG groups was higher than in control groups. Conclusion: Within the limitations of this DM animal study, gaseous ozone application accelerates xenograft resorption and enhances bone regeneration, especially in the early stages of bone healing.     

Comparison of platelet pellet and bioactive glass in periodontal regenerative therapy

Objective. In recent years, platelet-rich plasma combined with graft materials has been used for periodontal regeneration. The individual role of blood products with guided tissue regeneration in periodontal regenerative therapy is unclear and needs to be elucidated. The purpose of this study was to compare the clinical and radiological effectiveness of platelet pellet/guided tissue regeneration (PP/GTR) and bioactive glass/GTR (BG/GTR) treatments in patients with periodontal disease.

Material and methods. Using a split mouth design, 15 chronic periodontitis patients with pocket depths?≥?6 mm following periodontal initial therapy were randomly assigned to treatment with a combination of PP/GTR or BG/GTR in contralateral dentition areas. An absorbable membrane of polylactic acid was used GTR. The criteria for the comparative study were preoperative and postoperative 6 months pocket depth, clinical attachment level, and radiological alveolar bone level.

Results. Both treatment modalities resulted in significant pocket depth reduction and gain in clinical attachment and alveolar bone level compared to the preoperative values (p<0.01). Reduction in pocket depth, gain in clinical attachment and alveolar bone level were 4(3–6), 4.1±0.7, 4.9±1.4 mm in the PP/GTR group and 4(3–7), 4.1±1.2, 5.9±1.7 mm in the BG/GTR group, respectively. The differences between the two groups were not statistically significant (p>0.05).

Conclusions. Within the limits of this study, it was concluded that PP may be effective as a bioactive glass graft material and used as a graft material for treating intrabony defects. PP thus appears to be a suitable alternative in the regenerative treatment of intrabony periodontal defects.     

Nanocrystalline hydroxyapatite in periodontal bone regeneration: A systematic review

BackgroundPeriodontal diseases when persistent, results in periodontal pockets, attachment loss and progressive destruction of the alveolar bone. Grafting periodontal bone defects with bone substitute biomaterials has proven clinical success for accomplishing reconstruction of lost attachment apparatus, especially in deep intra-bony defects. Nanoparticles (NPs) have been considered indispensable in the future of health sciences and NP based alloplastic graft materials such as nanocrystalline hydroxyapatite (NCHA) hold great promise for regeneration of periodontal defects. Therefore the aim of this review is to evaluate the role of NCHA as an effective substitute for periodontal bone regeneration.Material & methodsPopular scientific databases such as PubMed (Medline), Cochrane database of clinical trials, Scopus (Elsevier), Web of science (Clarivate Analytics) and Google Scholar, were searched. The literature search was restricted to published reports in English, between January 2000 and December 2021. Database search returned 1227 results which were screened based on title, author names and publication dates.ResultsData from the 14 included studies were reviewed and tabulated. In the present review, all the studies reported using commercially available NCHA for periodontal bone regeneration.ConclusionNCHA is a suitable bone substitute material for periodontal bone regeneration, with outcomes comparable to that of conventionally used graft materials such as bovine xenograft and other synthetic alloplastic materials. While grafting with NCHA in intrabony periodontal defects, after any form of periodontal flap surgery or debridement, significantly improves bone regeneration by 6 months, addition of adjuncts like EMD and PRF further enhance the outcomes.     

Histomorphometric assessment of implant coated with mixture of nano-alumina and fluorapatite in rabbits

BackgroundThe application of nanoscale surface modification was found to be useful in the improvement of osseointegration of endosseous dental implants. The fluorapatite (FA)/alumina (Al₂O₃) mixture is recognized for its outstanding bioinertia and can significantly increase the biocompatibility and bioactivity of biomaterials.ObjectiveThe aim of the present work was to evaluate the bone response to nano-alumina- and fluorapatite-coated dental implants using rabbit tibiae.Material and MethodsThe coating was performed using the dip-coating method. Commercially pure titanium screw-type implants were used as a control group. The coated implants were the experimental group. Each group consisted of 12 screws that were surgically implanted in 6 healthy New Zealand rabbits. Histological and histomorphometric evaluations were performed at the bone to implant contact (BIC) interface, bone fraction area occupancy (BAFO) and fibrous tissue at 2 and 6 weeks of healing.ResultsThis analysis showed that the coated implants had more rapid osseointegration than the control group, with a significant difference after 2 and 6 weeks of healing for both groups. The histomorphometric evaluation demonstrated higher values for BIC% and BAFO% and lower values of fibrous tissue in the mixture-coated Ti implants than in the control group.ConclusionThe current study suggested that the nano-alumina and fluorapatite mixture coating is a favourable candidate for rapid osseointegration over uncoated implants.     

Autogenous Bone Marrow Aspirate Coated Synthetic Hydroxyapatite for Reconstruction of Maxillo-Mandibular Osseous Defects: A Prospective Study

Purpose

This prospective study was conducted to evaluate the bone regeneration capacity of synthetic hydroxyapatite mixed with autogenous bone marrow aspirate when used as a bone graft substitute in maxillo-mandibular osseous defects.

Methods

This study included nine patients with histopathalogically proven benign osteolytic lesions in maxilla and mandible that were treated with enucleation or marginal resection followed by bone marrow aspirate coated synthetic biphasic hydroxyapatite (hydroxyapatite and beta tricalcium phosphate) graft placement. Incorporation of graft was assessed based on Irwin’s radiologic staging. The efficacy of graft to form new bone was radiologically evaluated by observing the sequential changes of density at grafted site using gray scale level histogram which was processed in adobe photoshop 7.0 elements. Clinical assessment of recipient and donor sites was done.

Results

Based on Irwin’s radiologic staging, at 6 month follow up period, obvious incorporation of graft with new bone was observed. Sequential changes in bone density measured by gray scale histogram revealed initial resorption followed by replacement of BMA coated hydroxyapatite with new bone formation. None of the patients eventually had complications like infection, wound dehiscence, graft loss at recipient sites at 6 months follow up period.

Conclusion

Autogenous bone marrow aspirate in combination with synthetic hydroxyapatite is an effective option for accelerating bone regeneration in small to moderate sized jaw bone defects. This mixture provides all the three critical elements needed for bone regeneration (osteogenesis, osteoinduction and osteoconduction) with an added advantage of obviating donor site morbidity.

     

Volume changes of autogenous bone after sinus lifting and grafting procedures: A 6-year computerized tomographic follow-up

ObjectivesTo evaluate long-term bone remodelling of autografts over time (annually, for 6 years), comparing the block and particulate bone procedures for sinus floor elevation, as well as to evaluate the survival of positioned dental implants.Patients and methodsTwenty-three sinus lift procedures with autogenous bone were performed: seven sinus lift procedures using particulate graft and 10 with block autogenous bone were performed in 17 patients. Employing a software program, pre- and post-surgical computerized tomography (CT) scans were used to compare the volume (V) and density (D) of inlay grafts over time (up to 6 years), and to determine the percentage of remaining bone (%R). All variable (V, D and %R) measurements were then compared statistically.ResultsAt the 6-year survey for block form, a resorption of 21.5% was seen, whereas for particulate grafts there was a resorption of 39.2%. Both groups exhibited bone remodelling between the first and second follow-up which was significant regarding volume for the block form and regarding density for the particulate group.ConclusionsDuring the initial period of healing, the cortico-cancellous block bone grafted into the maxillary sinus underwent a negative remodelling of the volume, which is most probably due to graft cortex resorption, coupled with, primarily, an increase in density in the spongious area; for the particulate grafts, significant augmentations in density were obtained. The lack of significant differences among volumes was due to the wide degree of dispersion of the data. The rough data presented in this paper seem to support the use of a bone-block grafting procedure in maxillary sinus augmentation.     

Osseous ingrowth in allogeneic bone blocks applied for vertical bone augmentation: a preclinical randomised controlled study

Objectives

The aim of the present study was the qualitative and quantitative evaluation of osseous graft consolidation using allogeneic bone blocks for vertical bone augmentation in an animal model.

Material and methods

Standardised allogeneic and autologous bone blocks were fixed on the frontal skull of 20 adult female pigs and covered with a resorbable collagen membrane. Animals were sacrificed after 2 and 6 months. Specimens were histologically and histomorphometrically analysed focusing on the amount of vital bone, residual bone substitute material and connective tissue. Furthermore, the amount of expression of bone matrix proteins (collagen type I and osteocalcin) and de novo vessel formation (von Willebrand factor) were quantified by immunohistochemistry.

Results

Significantly more allogeneic bone blocks failed for both evaluation time points (p < 0.05). Allogeneic blocks showed significantly less vital bone with more connective tissue formation compared to autologous bone blocks. Increased vessel formation could be detected for both evaluation time points in the contact area of autologous bone with local bone. The expression of collagen type I and osteocalcin was significantly lower in the allogeneic bone graft.

Conclusions

Allogeneic cancellous bone blocks showed a significantly higher failure rate compared to autologous bone blocks. Allogeneic bone blocks seemed to negatively affect bone formation or negatively influence the host in the long term, and increased connective tissue formation and block loss should be anticipated.

Clinical relevance

In order to maintain patient safety and treatment success clinicians should be persuaded to make a conscious choice of the applied biomaterials with regard to their components and structure.

     

Medication-related osteonecrosis of the jaw in a minipig model: Parameters for developing a macroscopic,radiological, and microscopic grading scheme

ObjectivesTo devise a macroscopic, radiological, and histological scale for assessing pathological changes associated with medication-related osteonecrosis of the jaw in a minipig model.Materials and methodsMedication-related osteonecrosis of the jaw was induced in Göttingen minipigs by weekly intravenous administration of bisphosphonate (zoledronic acid) combined with a tooth extraction procedure. Controls either did not receive zoledronic acid or did not undergo tooth extraction. After 20 weeks, minipigs were euthanized and underwent computed tomography and micro-computed tomography scanning. The mandible underwent additional histological examination.ResultsThe most consistent macroscopic findings in animals that had developed bisphosphonate-related osteonecrosis of the jaw (BRONJ) were necrotic, denuded bone, and formation of fistula and pus. Under radiological examination, impaired extraction socket healing, decrease in attenuation of bone beneath the extraction site, and periosteal reaction were observed. Under histological examination, demineralization of the extracellular bone matrix, denuding of bone, and osteonecrosis were recorded.ConclusionThese parameters were used to develop a scoring system for grading BRONJ.     

Volumetric and linear changes at dental implants following grafting with volume-stable three-dimensional collagen matrices or autogenous connective tissue grafts: 6-month data

Objectives

The objective of this study was to test whether or not soft tissue augmentation with a volume-stable collagen matrix (VCMX) leads to similar volume gain around dental implants compared to autogenous subepithelial connective tissue graft (SCTG).

Materials and methods

In 12 adult beagle dogs, immediate implants were placed with simultaneous guided bone regeneration. After 25–45 weeks, soft tissue augmentation was randomly performed using VCMX, SCTG, or a sham-operated control. Impressions were taken pre-op and post-op (tissue augmentation) and again at sacrifice after healing periods of 4, 8, and 24 weeks. They were then digitized to allow for superimposition. Values of linear and volumetric changes were calculated.

Results

The median increase (pre-op to post-op) in buccal volume measured 0.92 mm for VCMX, 1.47 mm for SCTG, and 0.24 mm for SH. The values (pre-op to sacrifice) were ? 0.25 mm for VCMX, 0.52 mm for SCTG, and ? 0.06 mm for group SH. The median ridge width 2 mm below the crest measured ? 0.26 mm for VCMX, 0.53 mm for SCTG, and ? 0.15 mm for SH (pre-op to sacrifice).

Conclusions

Volume augmentation using VCMX and SCTG resulted in an increase in ridge dimension (pre- to post-op). During the follow-up, the volume decreased in all three groups to a level close to the situation prior to surgery.

Clinical relevance

Soft tissue volume augmentation around dental implants is usually performed using the patient’s own tissue. This therapy is associated with an increased morbidity due to a second surgical site. Soft tissue volume at implant sites can be augmented using VCMX and SCTG. The gain on top of the ridge appears not to be stable during the follow-up in both groups.

     

Are culture‐expanded autogenous bone cells a clinically reliable option for sinus grafting?

Objectives: This prospective clinical study was designed to examine the healing process during the first 12 months after sinus grafting (SG) with autogenous culture-expanded bone cells (ABC) and bovine bone mineral (BBM) histomorphometrically and radiologically.
Material and methods: Twenty-two sinuses of 12 patients (mean age 56.2±9.3 years) were grafted. Four weeks before, SG bone biopsies were obtained with a trephine burr and the bone cells were isolated and expanded. Every sinus was grafted with BBM and ABC. After 6 months, a biopsy was taken from each sinus and implants ( n =82) were placed. These were uncovered after another 6 months and fitted with dentures. The percent newly formed bone (NB) and the NB-to-BBM contact area were determined on undecalcified histologic sections. The sinus graft volume was evaluated by dental CT after SG (CT 1), after implant placement (CT 2) and after implant uncovery (CT 3).
Results: Postoperative healing was uneventful. The NB was 17.9±4.6% and the contact area 26.8±13.1%. The graft volume (in mm³) was 2218.4±660.9 at the time of CT 1, 1694±470.4 at the time of CT 2 and 1347.9±376.3 at the time of CT 3 ( P <.01). Three implants were lost after uncovery. Reimplantation and prosthodontic rehabilitation were successful throughout.
Conclusions: These results suggest that SG with ABC and BBM in a clinical setting provides a bony implant site which permits implant placement and will tolerate functional loading.