Bone microbial contamination influences autogenous grafting in sinus augmentation

Mucosal Fenestration After 2% Chlorhexidine Extrusion Used in Substitution of Sodium Hypochlorite: A Case Report

This report describes a case of sodium hypochlorite (NaOCl) and chlorhexidine (CHX) extrusion through the apical foramen, causing acute pain, swelling and mucosal fenestration. A 62-year-old woman was referred for endodontic treatment in the first left maxillary premolar with a diagnosis of necrotic pulp. After the root canal irrigation with 2.5% NaOCl, the patient felt a burning sensation and pain. Discrete swelling and redness were noted in the patient’s face at the end of the session. Antibiotic and corticosteroids were prescribed. In the next appointment, 2% CHX was used, but another episode of extrusion occurred, with a sudden acute pain and intense swelling within a few minutes after the injection. After 2 weeks, the patient exhibited a left-side facial swelling extending anterior and inferior to the left zygomatic arch and superior to the body of the mandible. Oral antibiotic and anti-inflammatory drugs were administered. After 10 days, the swelling had completely diminished, but a mucosal fenestration and tooth mobility were verified. A cone beam CT was requested and showed a periapical lesion involving both buccal and palatal roots. After a prosthetic evaluation, the tooth extraction was indicated. One week after tooth removal, the mucosa was completely healed.

Structural and functional changes of gut microbiota in ovariectomized rats and their correlations with altered bone mass

As a critical factor involved in the maintenance of physiological homeostasis, the gut microbiota (GM) reportedly plays a key role in bone development. To date, the association between the GM and steroid deficiency-induced osteoporosis remains poorly understood. Forty female Sprague Dawley rats were divided into an ovariectomy (OVX) or control group. We performed 16S rRNA and metagenome sequencing, to compare diversity, taxonomic differences, and functional genes. The GM composition did not change in the control group and the number of operational taxonomic units increased significantly following ovariectomy. Alpha diversity, determined by ACE estimator, CHAO estimator, the Shannon index, and the Simpson index showed an increasing trend after ovariectomy. Samples in the OVX group were well clustered both pre- and post-ovariectomy, as demonstrated by principal coordinate 1 (PC1) and PC2. Functional genes of GM, including those involved in synthesis and metabolism of carbohydrates and nucleotides, microbial structure, and heme, as well as hemin uptake and utilization, increased at the early stage of osteoporosis. We observed that Ruminococcus flavefaciens exhibited the greatest variation in abundance among the GM and this was also associated with osteoclastic indicators and the estrobolome. Specific changes in fecal microbiota are associated with the pathogenesis of steroid deficiency-induced osteoporosis.

Demineralized dentin and enamel matrices as suitable substrates for bone regeneration

Background

In recent decades, tooth derivatives such as dentin (D) and enamel (E) have been considered as potential graft biomaterials to treat bone defects. This study aimed to investigate the effects of demineralization on the physical-chemical and biological behavior of D and E.

Methods

Human D and E were minced into particles (Ø<1 mm), demineralized and sterilized. Thorough physical-chemical and biochemical characterizations of native and demineralized materials were performed by SEM and EDS analysis and ELISA kits to determine mineral, collagen type I and BMP-2 contents. In addition, MG63 and SAOS-2 cells were seeded on tooth-derived materials and Bio-Oss®, and a comparison of cell responses in terms of adhesion and proliferation was carried out.

Results

The sterilization process, as a combination of chemical and thermal treatments, was found to be effective for all materials. On the other hand, D demineralization allowed preserving the collagen content, while increasing BMP-2 bioavailability. D and demineralized D (dD) displayed excellent biocompatibility, even greater than Bio-Oss®. Conversely, the high mineral content displayed by E, as confirmed by EDS analysis, inhibited cell proliferation. Of note, even though the demineralization process was somehow less effective in E than in D, demineralized E (dE) displayed increased BMP-2 bioavailability and improved performance in vitro compared with native E.

Conclusions

Our results substantiate the idea that the demineralization process lead to an increase of BMP-2 bioavailability, thus paving the way toward development of more effective, osteoinductive tooth-derived materials for bone regeneration and replacement.

Autogenous bone grafts in oral implantology-is it still a "gold standard"? A consecutive review of 279 patients with 456 clinical procedures

Background

This study assessed the clinical outcomes of graft success rate and early implant survival rate after preprosthetic alveolar ridge reconstruction with autologous bone grafts.

Methods

A consecutive retrospective study was conducted on all patients who were treated at the military outpatient clinic of the Department of Oral and Plastic Maxillofacial Surgery at the military hospital in Ulm (Germany) in the years of 2009 until 2011 with autologous bone transplantation prior to secondary implant insertion. Intraoral donor sites (crista zygomatico-alveolaris, ramus mandible, symphysis mandible, and anterior sinus wall) and extraoral donor site (iliac crest) were used. A total of 279 patients underwent after a healing period of 3–5 months routinely computer tomography scans followed by virtual implant planning. The implants were inserted using guided oral implantation as described by Naziri et al. All records of all the consecutive patients were reviewed according to patient age, history of periodontitis, smoking status, jaw area and dental situation, augmentation method, intra- and postoperative surgical complications, and surgeon’s qualifications. Evaluated was the augmentation surgical outcome regarding bone graft loss and early implant loss postoperatively at the time of prosthodontic restauration as well a follow-up period of 2 years after loading.

Results

A total of 279 patients underwent 456 autologous augmentation procedures in 546 edentulous areas. One hundred thirteen crista zygomatico-alveolaris grafts, 104 ramus mandible grafts, 11 symphysis grafts, 116 grafts from the anterior superior iliac crest, and 112 sinus lift augmentations with bone scrapes from the anterior facial wall had been performed. There was no drop out or loss of follow-up of any case that had been treated in our clinical center in this 3-year period. Four hundred thirty-six (95.6%) of the bone grafts healed successfully, and 20 grafts (4.4%) in 20 patients had been lost. Fourteen out of 20 patients with total graft failure were secondarily re-augmented, and six patients wished no further harvesting procedure. In the six patients, a partial graft resorption was detected at the time of implantation and additional simultaneous augmentation during implant insertion was necessary. No long-term nerve injury occurred. Five hundred twenty-five out of 546 initially planned implants in 259 patients could be inserted into successfully augmented areas, whereas 21 implants in 20 patients due to graft loss could not be inserted. A final rehabilitation as preplanned with dental implants was possible in 273 of the 279 patients. The early implant failure rate was 0.38% concerning two out of the 525 inserted implants which had to be removed before the prosthodontic restoration. Two implants after iliac crest augmentation were lost within a period of 2 years after loading, concerning a total implant survival rate after 2 years of occlusal loading rate of 99.6% after autologous bone augmentation prior to implant insertion.

Conclusions

This review demonstrates the predictability of autologous bone material in alveolar ridge reconstructions prior to implant insertion, independent from donor and recipient site including even autologous bone chips for sinus elevation. Due to the low harvesting morbidity of autologous bone grafts, the clinical results of our study indicate that autologous bone grafts still remain the “gold standard” in alveolar ridge augmentation prior to oral implantation.

Plant-derived pectin nanocoatings to prevent inflammatory cellular response of osteoblasts following Porphyromonas gingivalis infection

Background

Bioengineered plant-derived Rhamnogalacturonan-Is (RG-Is) from pectins are potential candidates for surface nanocoating of medical devices. It has recently been reported that RG-I nanocoatings may prevent bacterial infection and improve the biocompatibility of implants. The aim of the study was to evaluate in vitro impact of bioengineered RG-I nanocoatings on osteogenic capacity and proinflammatory cytokine response of murine osteoblasts following Porphyromonas gingivalis infection.

Methods

Murine MC3T3-E1 osteoblasts and isolated primary calvarial osteoblasts from C57BL/6J (B6J osteoblasts) mice were infected with P. gingivalis and incubated on tissue culture polystyrene plates with or without nanocoatings of unmodified RG-Is isolated from potato pulps (PU) or dearabinanated RG-Is (PA). To investigate a behavior of infected osteoblasts cultured on RG-Is cell morphology, proliferation, metabolic activity, mineralization and osteogenic and pro-inflammatory gene expression were examined.

Results

Following P. gingivalis infection, PA, but not PU, significantly promoted MC3T3-E1 and BJ6 osteoblasts proliferation, metabolic activity, and calcium deposition. Moreover, Il-1b, Il-6, TNF-α, and Rankl gene expressions were downregulated in cells cultured on PU and to a higher extent on PA as compared to the corresponding control, whereas Runx, Alpl, Col1a1, and Bglap gene expressions were upregulated vice versa.

Conclusion

Our data clearly showed that pectin RG-Is nanocoating with high content of galactan (PA) reduces the osteoblastic response to P. gingivalis infection in vitro and may, therefore, reduce a risk of inflammation especially in immunocompromised patients with rheumatoid or periodontal disorders.

Clinical results of autologous bone augmentation harvested from the mandibular ramus prior to implant placement. An analysis of 104 cases

Background: The aim of this study was the evaluation of the clinical success and complication rates associated with autologous bone grafts harvested from the mandibular ramus for alveolar ridge augmentation and the identification of possible risk factors for graft failure.

Methods: In a consecutive retrospective study 86 patients could be included. In these patients a total of 104 bone grafts from the mandibular ramus were harvested for alveolar ridge augmentation. Medical history, age of patient, smoking status, periodontal status and complications were recorded. The need for bone grafting was defined by the impossibility of installing dental implants of adequate length or diameter to fulfill prosthetic requirements, or for aesthetic reasons. The surgical outcome was evaluated concerning complications at the donor or at the recipient site, risk factors associated with the complications and graft survival. All patients were treated using a two-stage technique. In the first operation bone blocks harvested from the retromolar region were placed as lateral or vertical onlay grafts using augmentation templates and were fixed with titanium osteosynthesis screws after exposure of the deficient alveolar ridge. After a healing period of 3–5 months computed tomography scans were performed followed by virtual implant planning and the implants were inserted using guided dental implantation.

Results: 97 of the 104 onlay bone grafts were successful. In only 7 patients a graft failure occurred after a postsurgical complication. No long-term nerve damage occurred. Postoperative nerve disturbances were reported by 11 patients and had temporary character only. After the healing period between 4 to 5 months, 155 implants were placed (39 in the maxilla, 116 in the mandible). A final rehabilitation with dental implants was possible in 82 of the 86 patients. Except the 7 graft failures, all recorded complications were minor complications which could be easily treated successfully without any long-term problems. Complications at the donor site were recorded in 3 patients and 17 patients experienced complications at the recipient site. Three of 7 patients with graft failure, were secondarily augmented with a new retromolar graft, harvested from the contra-lateral site and dental implants could be successfully inserted later. No association between complications and smoking habit, age of patient, jaw area, and dental situation (tooth gap or free dental arch) could be detected.

Conclusions: Retromolar bone grafts are an effective and safe method for the reconstruction of small- to medium-sized alveolar defects of the maxilla and mandible prior to dental implantation and show a low graft failure rate.

Bacterial influence on consolidation of bone grafts in maxillary sinus elevation

OBJECTIVES

The aim of this study was to identify microorganisms present on the maxillary sinus floor at the moment of sinus elevation surgery and, using tomography, to investigate the repercussions these might have for regenerated bone 9 months after the procedure.

MATERIALS AND METHODS

174 patients (90 women and 84 men) with a mean age of 55.92 years underwent 227 sinus elevations (120 left sinus, 107 right sinus). As the membrane was lifted, a sample of the maxillary sinus floor was collected with a cotton swab, and placed on a blood agar and chocolate agar culture to incubate for 48 h at 37°C; the samples then underwent microbiological analysis. Orthopantomographs and computerized tomographs were made immediately after the sinus grafting and after 9 months to measure the amount of remaining and regenerated bone in vertical and transversal direction.

RESULTS

18.1% of 227 cultures were bacteria-positive. 45% of the germs were of the Streptococcus genus, most of which belonged to the S. viridans group (61.1%). Patients presenting negative cultures had 5% more regenerated bone than patients with bacteria-positive cultures, which represents an additional 2.28 mmof vertical bone (with a confidence interval between 0.83 mm and 3.73 mm).

CONCLUSIONS

Patients with bacteria-positive cultures obtained previously to the sinus grafting procedure have greater risk of bone height loss after 9 months, which indicates that bacterial contamination may influence bone graft regeneration.

A clinical study of the outcomes and complications associated with zygomatic buttress block bone graft for limited preimplant augmentation procedures

PURPOSE

The aim of this study was to evaluate the possibility of using the zygomatic buttress as an intraoral bone harvesting donor site and determine the safety of this harvesting procedure for later optimal positioning of dental implants in accordance with prosthodontic and functional principles.

MATERIAL AND METHODS

A consecutive retrospective study was conducted on patients who had been treated at the Department of Oral and Maxillofacial Surgery of Ulm military and academic hospital, over a 3-year period (January 2008 to December 2010). Medical history, smoking status, area of surgery, and complications were recorded. The need for bone grafting was defined by the impossibility of installing implants of adequate length or diameter to fulfill prosthetic requirements, or for esthetic reasons. The patients were treated using a 2-stage technique. During the first operation, bone blocks harvested from the zygomatic buttress region were placed as lateral onlay grafts and fixed with titanium osteosynthesis screws after exposure of the deficient alveolar ridge. After 3-6 months of healing, the flap was reopened, the screws removed and the implants placed.

RESULTS

A total of 113 zygomatic buttress bone block grafts in 112 patients were performed. Graft loss and graft removal were defined as failure; swelling, wound dehiscence, infection with pus, temporary paresthesia, and perforations of the maxillary sinus membrane were defined as complications. According to our criteria, 4 (3.5%) of the patients presented postoperative complications of the donor site and 20 (17.8%) of the recipient site. Throughout, 93 (82.3%) of the bone grafts were successful and 20 (17.6%) had complications, regardless of the final success of the implant procedure. Smoking was associated with a high rate of complications and graft failure. Early graft exposure appeared to compromise the results, whereas pain and swelling were comparable to usual dentoalveolar procedures. However, in 1.7% of all cases, concerning 2 patients, the final rehabilitation with dental implants was not possible.

CONCLUSIONS

The zygomatic buttress block bone graft is a safe intraoral donor site for the reconstruction of small- to medium-sized alveolar defects, providing the greatest surgical access with minimal postoperative complications.

The Volume Behavior of Autogenous Iliac Bone Grafts After Sinus Floor Elevation: A Clinical Pilot Study

Iliac crest is still regarded as one of the most viable source of autogenous graft materials for extensive sinus floor elevation. Three-dimensional resorption behavior has to be taken into account in anticipation of the subsequent insertion of dental implants. We performed 3-dimensional volume measurements of the inserted bone transplants in 11 patients (6 women and 5 men; mean age = 2.3 years) who underwent bilateral sinus floor elevation with autogenous iliac crest grafts. In order to determine the respective bone graft volumes, cone-beam computerized tomography studies of the maxillary sinuses were carried out directly after the operation (T0), as well as 3 months (T1) and 6 months (T2) postoperatively. The acquired DICOM (Digital Imaging and Communications in Medicine) data sets were evaluated using suitable analysis software. We evaluated statistical significance of graft volumes changes using a linear mixed model with the grouping factors for time, age, side, and sex with a significance level of P = .05. 38.9% of the initial bone graft volume, which amounted to 4.2 cm(3), was resorbed until T1. At T2, the average volume again decreased significantly by 18.9 % to finally reach 1.8 cm(3). The results show neither age nor side dependency and apply equally to both sexes. Without functional load, iliac bone grafts feature low-volume stability in sinus-augmentation surgery. Further clinical and animal studies should be done to detect the optimal timing for implant placement.

Effect of human beta-defensin-3 on the proliferation of fibroblasts on periodontally involved root surfaces

Human beta-defensin-3 (HBD-3) has versatile antibacterial activity against oral bacteria and can promote the proliferation of fibroblasts. The goal of the present study was to investigate the effect of HBD-3 on attachment and proliferation of periodontal ligament cells (PDL) onto the periodontitis affected root surfaces. PDL cells were seeded onto healthy and diseased root specimens with scaling and root planing (SRP), SRP & HBD-3 (100 ng/ml), or SRP & HBD-3 (200 ng/ml) treatment for 1, 3, and 7 days incubation. The results showed that HBD-3, especially in the 200 ng/ml group, significantly promoted fibroblast attachment and proliferation onto the diseased root surfaces. The cell number in the HBD-3 group was much greater than in the group treated with SRP alone. On day 7, the cells in the HBD-3 were well-spread and formed a network similar to those on the surfaces of the healthy root specimens. These results suggest that HBD-3 could play an important role in antibacterial activity and fibroblast proliferation, thus promoting periodontal regeneration. Meanwhile, HBD-3 might act as a potent regeneration-promoter in infectious diseases.

Incomplete bone formation after sinus augmentation: A case report on radiological findings by computerized tomography at follow-up

Purpose

The aim of this case report is to present a case of incomplete bone formation after sinus augmentation.

Methods

A patient having alveolar bone resorption of the maxillary posterior edentulous region and advanced pneumatization of the maxillary sinus was treated with sinus elevation using deproteinized bovine bone in the Department of Periodontology, Kyung Hee University School of Dentistry and re-evaluated with computed tomography (CT) follow-up.

Results

Even though there were no significant findings or abnormal radiolucency on the panoramic radiograph, incomplete bone formation in the central portion of the augmented sinus was found fortuitously in the CT scan. The CT scan revealed peri-implant radiolucency in the apical portion of the implant placed in the augmented maxillary sinus. Nevertheless, the dental implants placed in the grafted sinus still functioned well at over 15 months follow-up.

Conclusions

The result of this case suggests that patients who received maxillary sinus augmentation may experience incomplete bone formation. It is possible that 1) osteoconductive graft material with poor osteogenic potential, 2) overpacking of graft material that restricts the blood supply, and 3) bone microbial contamination may cause the appearance of incomplete bone formation after sinus augmentation. Further studies are needed to elucidate the mechanism of this unexpected result and care must be taken to prevent it.

Bone microbial decontamination agents in osseous grafting: an in vitro study with fresh human explants

BACKGROUND

Establishing a safe prophylactic antimicrobial protocol in bone grafting may enhance osseous volume outcomes. The purpose of this in vitro study is to assess human osteoblast response and safety after explant antimicrobial exposure.

METHODS

Fresh human bone explants were exposed to three antimicrobials: povidone-iodine (PovI; 0.05%, 1%, and 5%), chlorhexidine (CHX; 0.2% and 1%), and sodium hypochlorite (NaOCl; 2.5%, 4.5%, and 5.25%) at different times (15, 30, 45, and 60 seconds) and concentrations to assess cellular toxicity. Explants were washed three times with saline after exposure. Controls, explants cultured in the absence of antimicrobials, were performed for all experimental situations tested. Trials were conducted in triplicate. Particle size influence on osteoblast growth was determined between bone fragments with a diameter <2 and ≥2 to 5 mm. Test and control groups were monitored by light microscopy to evaluate cellular growth. Osteoblast differentiation and morphology was assessed by alkaline phosphatase activity and scanning electron microscopy (SEM).

RESULTS

Osteoblast growth was similar for particles <2 and ≥2 to 5 mm. Alkaline phosphatase control reference values were not significantly different from test groups (0.35 mU/mL ± 0.004 versus 0.34 mU/mL ± 0.009; P >0.05). Light microscopy showed on average 97% osteoblastic growth for bone particles exposed to PovI 5% and CHX 0.2% for all times and CHX 1% up to 30 seconds. The odds ratio of positive osteoblastic growth after a 30-second 2.5% NaOCl exposure was 2.4 times higher than after 5.25%. On average, one of two replicas yielded positive growth with 2.5% NaOCl and one of three with 5.25%. After 60-second explant exposure, positive osteoblastic growth was 7.7 times more likely to occur with 5% PovI or 0.2% CHX than with 5.25% NaOCl (P <0.05). SEM analysis confirmed light microscopy similar cellular adhesion and osteoblast phenotypic features between test and control groups.

CONCLUSIONS

Best osteoblastic growth occurred after bone PovI exposure and CHX 0.2%. Cellular toxicity seems to be influenced by the type of antimicrobial, concentration, and exposure time. SEM analysis confirmed absence of osteoblast phenotypic alterations after exposure. Decontamination agents can safely be used in bone transplantation using up to 5% PovI and 0.2% CHX for 1 minute and CHX 1% for 30 seconds.