Grafting of large defects of the jaws with a particulate dentin-plaster of paris combination

Calcium Sulfate Disks for Sustained-Release of Amoxicillin and Moxifloxacin for the Treatment of Osteomyelitis

The purpose of this in vitro study was to develop calcium sulfate (CS)-based disks infused with an antimicrobial drug, which can be used as a post-surgical treatment modality for osteomyelitis. CS powder was embedded with 10% antibiotic, amoxicillin (AMX) or moxifloxacin (MFX), to form composite disks 11 mm in diameter that were tested for their degradation and antibiotic release profiles. For the disk degradation study portion, the single drug-loaded disks were placed in individual meshes, subsequently submerged in phosphate-buffered saline (PBS), and incubated at 37 °C. The disks were weighed once every seven days and analyzed via Fourier-transform infrared spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, and scanning electron microscopy. During the antibiotic release analysis, composite disks were placed in PBS solution, which was changed every 3 days, and analyzed for antibiotic activity and efficacy. The antibacterial effects of these sustained-release composites were tested by agar diffusion assay using Streptococcus mutans (S. mutans) UA 159 as an indicator strain. The degradation data showed significant increases in the degradation of all disks with the addition of antibiotics. Following PBS incubation, there were significant increases in the amount of phosphate and decreases in the amount of sulfate. The agar diffusion assay demonstrated that the released concentrations of the respective antibiotics from the disks were significantly higher than the minimum inhibitory concentration exhibited against S. mutans over a 2-3-week period. In conclusion, CS-antibiotic composite disks can potentially serve as a resorbable, osteoconductive, and antibacterial therapy in the treatment of bone defects and osteomyelitis.

Nano apatite growth on demineralized bone matrix capped with curcumin and silver nanoparticles: Dental implant mechanical stability and optimal cell growth analysis

OBJECTIVES

The prevention of implant-associated infections is becoming increasingly clinically important in the field of dentistry. Extensive investigations into the development of innovative antibacterial materials that interact effectively to reinforce their functionality are currently being conducted in the biomedical sector. In the present study, a novel dental nano putty (D-nP) has been developed using demineralized bone matrix (DBM), calcium sulfate hemihydrate (CSH), curcumin nanoparticles (CU-NPs), and silver nanoparticles (AgNPs).

METHODS

The produced D-nP was evaluated using physicochemical, mechanical, and in vitro analyses. Surface characterization, particularly the analysis of calcium and phosphorus content, was performed before and after immersion in the simulated body fluid (SBF). In addition, the impact of surface treatment on biological activity was studied.

RESULTS

The results showed that the mechanical properties of the D-nP were outstanding and its performance is promising. D-nP exhibited excellent antibacterial activity against Actinomyces naeslundii (5.22 ± 0.07 mm) and Streptococcus oralis (5.41 ± 0.1 mm). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay was conducted using MG-63 osteoblast cells, which exhibited 95 % viability in D-nP.

CONCLUSIONS

Based on these characterization results, the D-nP developed in this study exhibited excellent performance for tooth tissue in bone repair.

Autologous Tooth Granulometry and Specific Surface Area with Three Grinding Methods: An In Vitro Study

A postextraction socket becomes a clinical challenge due to the fact that a series of changes associated with bone remodelling and resorption of the socket that occur after extraction, which limits the aesthetic and functional prognosis of implant-supported rehabilitations. It has been studied that the use of the autologous tooth-derived graft (ATDG) has regenerative properties and could therefore be useful for solving this type of problem. There is no consensus in the scientific literature on a standardized protocol for the use of the autologous tooth. Therefore, the aim of the present study was to evaluate the most relevant parameters to achieve the best properties of ground ATDG using three methods, namely Gouge forceps, electric grinder, and manual, that made up the study group (SG) and compared with the control group (CG) consisting of Bio-Oss®. The sample obtained by the electric grinder had the highest value of specific surface area (2.4025 ± 0.0218 m2/g), while the particle size as average diameter (751.9 µm) was the lowest and most homogeneous of the three groups. Therefore, the electric grinder allowed for obtaining ATDG with more regenerative properties due to its specific surface-area value and particle size in accordance with the xenograft with the greatest bibliographical support (Bio-Oss®). The higher specific surface increases the reaction with the physiological media, producing faster biological mechanisms.

The effect of autogenous tooth bone graft material without organic matter and type I collagen treatment on bone regeneration

Objectives

The aim of this study is to examine the effect of particulate autogenous tooth graft removed with organic matter and type I collagen addition on bone regeneration and to validate the possibility of useful allograft material for jaw defects.

Material and methods

Autogenous tooth bone maker (Korean Dental Solution® KOREA) made particulate autogenous tooth not including organic matter. We used to the developed tooth grafts for experiment. Cell adhesion test with hemacytometer and energy dispersive X-ray spectroscopy (Supra40 VP®, Carl Zeiss, Germany) analysis about the particulate autogenous tooth and type I collagen were performed. Rabbits were divided into three groups: bone graft with organic matter (OM) removing particulate autogenous tooth group, bone graft with OM removing particulate autogenous tooth and type I collagen group, and a control group. Bone grafting was performed in rabbit’s calvaria. The rabbits were sacrificed at different interval at 1, 2, 4, and 6 weeks after bone grafting for the histopathologic observation and observed the effect of bone regeneration by SEM, H-E & Masson stains, osteocalcin IHC staining.

Result

In vitro cytopathological study showed affinity for cells, cell attachment pattern, and cell proliferation in the order of control group, OM-removed and collagen-treated group, OM-removed particulate autogenous tooth group. The results of the degree of mineralization were opposite to those of the previous cell experimental results, and the OM-removed group, OM-removed group and collagen-treated group were relatively higher than the control group. Histopathologic analysis showed that vascularization and neonatal bone formation were higher in particulate autogenous tooth group with removing OM and with addition of collagen than control group and group of OM removed only. Immunohistochemical analysis showed that osteocalcin (OSC) expression was not observed in the control group, but at 4 weeks groups, OSC expression was observed the OM removed and OM-removed-collagen-treated particulate autogenous tooth, and the degree of expression was somewhat stronger in group of the OM removed and collagen additionally treated particulate autogenous tooth.

Conclusion

Particles that do not contain organic matter, the saint tooth, was responsible for sufficient bone graft material through the role of space maintenance and bone conduction, and further improved bone formation ability through additional collagen treatment. Therefore, research on various extracellular substrates and autologous bone grafting materials is necessary, and through this, it is possible to lay the foundation for a new type of autologous bone grafting material with excellent academic and technical utility.

Effect of Autogenous Dentin Graft on New Bone Formation

ABSTRACT

The aim of this study is to analyze the effects of autogenous dentin graft and mixture of autogenous dentin graft and platelet-rich fibrin (PRF) applied to the tooth extraction sockets on bone healing process. A total of 57 extraction sockets in 9 patients who were planned to be treated with dental implant after tooth extraction were evaluated in this study. Extraction sockets were divided randomly into 3 groups for each patient. In the first group, sockets were filled with autogenous dentin graft (Group D). In the second group, sockets were filled with the mixture of PRF and autogenous dentin graft (Group DP). In the third group, sockets were left empty as the control group (Group C). After 3 months, histological and immunohistochemical evaluations were performed on the samples taken during the implant surgery. Additionally, samples obtained from each group were examined by scanning electron microscopy. According to the histopathological findings, when the groups were compared in terms of new bone formation there was a significant difference between Group DP, both Group C, and Group D (P = 0.00), (P = 0.001). These findings supported by immunohistochemical results that showing increased bone morphogenetic protein-2 and Runt-related transcription factor-2 expression in Group DP. It has been concluded that undemineralized autogenous dentin graft has bone formation capacity on early period of bone healing. It can be used as bone graft material in augmentation procedures and its combined use with PRF accelerates new bone formation.

Dentin-Derived Inorganic Minerals Promote the Osteogenesis of Bone Marrow-Derived Mesenchymal Stem Cells: Potential Applications for Bone Regeneration

Background

Oral and maxillofacial bone loss is highly prevalent among populations, and nowadays, increased attention has been focused on dentin derivatives serving as desirable graft materials for bone regeneration. In this study, dentin-derived inorganic mineral (DIM) was fabricated with a high-temperature calcination technique and the effects of DIM on the osteogenic differentiation of bone marrow-derived mesenchymal stem cells (BMMSCs) and the bone formation were elucidated.

Methods

The effects of DIM on BMMSC proliferation and apoptosis capacity were evaluated by CCK-8, flow cytometry, and EdU assays. Alkaline phosphatase (ALP) activity detection, ALP staining, alizarin red staining, and osteogenic marker expression analysis were performed to investigate the influence of DIM on the osteogenic differentiation of BMMSCs, as well as the relevant signal mechanisms. The model of critical-sized defects in the calvarium of rats was constructed for exploring the in vivo efficiency of DIM on bone regeneration.

Results

Cell viability assays indicated that DIM had no cytotoxicity. BMMSCs cultured with DIM presented a higher level of osteogenic differentiation ability than those in the control group. The activation in ERK and p38 signals was detected in DIM-treated BMMSCs, and both pathways and osteogenic process were suppressed while using ERK inhibitor U0126 and p38 inhibitor SB203580, respectively. Furthermore, the animal experiments revealed that DIM could dramatically enhance new bone formation compared to the control group.

Conclusion

DIM could promote BMMSC osteogenic differentiation via triggering the ERK and p38 MAPK signaling pathways and might be a novel predictable material for facilitating bone formation.

Guided bone regeneration using autogenous tooth bone graft in implant therapy: case series

Recently, techniques have been reported that involve the preparation of extracted teeth from patients used as particulated bone graft materials for bone graft purposes. For implant placement and bone graft, autogenous teeth bone graft materials were used in 15 patients, and clinically excellent results were obtained. In histological examination, favorable bony healing by osteoconduction was observed.

Histomorphometric Analysis of Contaminated Autogenous Tooth Graft Materials After Various Sterilization

PURPOSE

The purpose of this study was to evaluate histomorphometrically contaminated autogenous tooth graft materials, which were resterilized.

MATERIALS AND METHODS

The intentional defects (diameter: 8 mm, depth: 4 mm) were formed around implant fixture on the iliac crest of 6 mongrel dogs. Autogenous tooth graft materials were made by extracted premolars. After the contamination of the tooth materials, graft procedure was performed; no contaminated group (control group), contaminated groups (nonsterilization group [group 1], ethylene oxide [EO] gas group [group 2], and autoclave group [group 3]). The bone-to-implant contact (BIC) and the new bone formation rate (NBFR) were evaluated after sacrifice.

RESULTS

The BIC and NBFR of groups 1 and 3 were significantly lower than the control group after 4 weeks. The BIC and NBRF of group 3 were significantly lower than the control group after 8 weeks. However, the BIC and NBRF of group 2 was not significantly different comparing with the control group after 4 and 8 weeks.

CONCLUSION

Sterilization using EO gas may be more favorable than high-pressure sterilization in cases the reuse of contaminated autogenous tooth graft materials.

Effect on bone formation of the autogenous tooth graft in the treatment of peri-implant vertical bone defects in the minipigs

Background

The aim of this study was to evaluate the effect of autogenous tooth bone as a graft material for regeneration of bone in vertical bony defects of the minipigs.

Material and Methods

Six minipigs were used in this study. Four molars were extracted in the right mandibular dentition and sent to the Korea Tooth Bank for fabrication of autogenous tooth bone. Ten days later, each extraction site was implanted with MS Implant Narrow Ridge 3.0x10mm fixture (Osstem, Seoul, Korea) after standardized 2mm-sized artificial vertical bony defect formation. Pineappleshaped Root-On type autogenous tooth bones were applied to the vertical defects around the neck area of the posterior three fixtures and the fore-most one was not applied with autogenous bone as a control group. Each minipig was sacrificed at 4, 8, 12 weeks after fixture installation and examined radiologically and histologically. Histological evaluation was done under light microscope with Villanueva osteochrome bone staining with semi-quantitative histomorphometric study. Percentage of new bone over total area (NBF) and bone to implant contact (BIC) ratio were evaluated using digital software for area calculation.

Result

NBF were 48.15 ± 18.02%, 45.50 ± 28.37%, and 77.13 ± 15.30% in 4, 8, and 12 weeks, respectively for experimental groups. The control group showed 37.00 ± 11.53%, 32.25 ± 26.99%, and 1.33 ± 2.31% in 4,8,12 weeks, respectively. BIC ratio were 53.08 ± 19.82%, 45.00 ± 28.37%, and 75.13 ± 16.55% in 4,8,12 weeks, respectively. Those for the control groups were 38.33 ± 6.43%, 33.50 ± 29.51 %, and 1.33 ± 2.31% in 4, 8, 12 weeks, respectively.

Conclusion

Autogenous tooth bone showed higher score than control group in NBF and BIC in all the data encompassing 4,8,12 weeks specimens, but statistically significant only 12 weeks data in both NBF and BIC.

Osteoconduction capacity of human deciduous and permanent teeth ash in a rat calvarial bone defect model

The aim of this study was to confirm the osteoconduction capacities and determine the potential of permanent teeth ash (PTA), and deciduous teeth ash (DTA) as bone substitutes. Rats (n = 71) were divided randomly into four groups: sham, micro macroporous biphasic calcium phosphate (MBCP), PTA, and DTA. A sample of the each group was transplanted into preformed 8-mm calvarial defects (one per rat). The density of new bone was calculated and the crystallinities of the PTA and DTA were analyzed by X-ray diffraction. The degree of new bone formation was high in the MBCP and DTA groups but low in the PTA groups. The DTA was highly crystalline, whereas the PTA was not. The percentages of β-tricalcium phosphate in the DTA and PTA were 10.7 and 3.7%, respectively. DTA has a high osteoconduction capacity, suggesting that it is a useful bone substitute.

Osteogenic ability according to the decalcified modality of auto-tooth bone grafts in peri-implant defects in dogs

PURPOSE

The purpose of this study was to evaluate the bone generation capacity of the autotransplantation material with clinical and histological analyses after controlled acid treatment conditions.

MATERIAL AND METHODS

Bony defects were formed in the femur. Then, autotransplantation material was grafted after hydroxyapatite-coated implant placement. Experimental groups were classified according to the acid treatment method: 2% H2SO4 (group 1), 2% HCl (group 2), 2% HNO3 (group 3), or 2% ethylenediaminetetraacetic acid (EDTA) (group 4).

RESULTS

The new bone formation area and bone-implant contact (BIC) of the autotransplantation materials were measured after 8 weeks. The new bone formation area in experimental groups 2, 3, and 4 were greater than that in the control group (no graft) and in experimental group 1 at 8 weeks, and the BIC of experimental group 4 was greater than that in the control group and in experimental group 1; these differences showed statistical significance (P < 0.05).

CONCLUSION

Auto-tooth bone treated with EDTA resulted in more effective bone formation in dogs' femurs than bone treated with other solutions.

Using rigidly fixed autogenous tooth graft to repair bone defect: an animal model

OBJECTIVE

This study describes a new approach to regenerate bone defect using autogenous tooth.

MATERIALS AND METHODS

Freshly extracted teeth were used as autogenous grafts. Teeth were sectioned, cut into desired shape, and disinfected. The grafts were rigidly fixed to the mandibular defects in eighteen rabbits using titanium screws to achieve good stability. Every six rabbits were stochastically sacrificed at 1, 3, and 6 months after implantation, respectively. For all specimens, clinical, radiographical, and histological measurements were performed.

RESULTS

The boundaries of the grafts were distinctly visible in the implanted area during the first and third month. However, the teeth grafts were fully covered by new bone by the sixth month. The radiograph demonstrated the progressive change in the bone and grafted tooth interface from radiolucency to radiopacity during different time periods. Histologically, vascularization led to a temporary fibrous integration in the graft-bone interface. The bone contact rate of 1 and 3 months was significantly lower than that of the 6 months. During this period, grafts were gradually resorbed and replaced by new bone.

CONCLUSION

Rigid fixation of autogenous tooth could serve as a novel approach for the repair of bone defect.

Porcine study on the efficacy of autogenous tooth bone in the maxillary sinus

OBJECTIVES

This study sought to elucidate the effect of autogenous tooth bone material by experimenting on minipig's maxillary sinus and performing histological and histomorphometric analyses.

MATERIALS AND METHODS

Five 18-24 month-old male minipigs were selected, and right maxillary sinuses were grafted with bone graft material made of their respective autogenous teeth extracted eight weeks earlier. The left sides were grafted with synthetic hydroxyapatite as control groups. All minipigs were sacrificed at 12 weeks after bone graft, which was known to be 1 sigma (σ) period for pigs. Specimens were evaluated histologically under a light microscope after haematoxylin-eosin staining followed by semi-quantitative study via histomorphometric analysis. The ratio of new bone to total area was evaluated using digital software for calculation of area.

RESULTS

All specimens were available, except one on the right side (experimental group), which was missing during specimen preparation. This study demonstrated new bone at the periphery of the existing bone in both groups, showing evidence of bone remodeling, however, encroachment of new bone on the central part of the graft at the 1 σ period was observed only in the autogenous tooth bone group (experimental group). Histomorphometric analysis showed more new bone formation in the experimental group compared to the control group. Although the difference was not statistically significant (P>0.05), the mean percentage area for new bone for the experimental and control groups were 57.19%±11.16% and 34.07%±13.09%, respectively.

CONCLUSION

The novel bone graft material using autogenous tooth is a good alternative to autogenous bone, comparable to autogenous bone, and outperforming synthetic hydroxyapatite bone graft materials in terms of bone regeneration capacity. Augmentation with autogenous tooth bone materials will reduce donor site morbidity without hampering the safety of the autogenous bone graft.

Histomorphometric analysis of bone formation in bony defects around implants in adult dogs: a comparison of grafts of low and high heat-treated autogenous tooth ash

PURPOSE

The purpose of this study was to compare the bone formation of autogenous tooth ash treated with different temperatures.

MATERIALS AND METHODS

Heat treatment was rendered by powder after extraction of teeth from dogs. The bony defects were made at iliac and resorbable blast medium surfaced implant placement and bone graft was performed; no bone graft group (control group), low heat-treated tooth ash group (group 1), high heat-treated tooth ash group (group 2). Right side had healing periods of 12 weeks, and the left side had 6 weeks. Histomorphometrical analysis was performed at 12 weeks.

RESULTS

The control group had poor bone formation and showed large loose connective tissue. Group 1 displayed good healing and bone formation. Group 2 showed higher rate of bone formation than group 1 and the control group. The high heat-treated tooth ash group showed a statistically significant increase in the rate of bone formation in the early stage.

CONCLUSION

The heat-treated autogenous tooth ash powder showed excellent new bone formation. The temperature of heat treatment is an important factor in new bone formation. The high heat treatment was the optimal treatment method for making tooth ash than the low heat treatment.

Tooth-derived bone graft material

With successful extraction of growth factors and bone morphogenic proteins (BMPs) from mammalian teeth, many researchers have supported development of a bone substitute using tooth-derived substances. Some studies have also expanded the potential use of teeth as a carrier for growth factors and stem cells. A broad overview of the published findings with regard to tooth-derived regenerative tissue engineering technique is outlined. Considering more than 100 published papers, our team has developed the protocols and techniques for processing of bone graft material using extracted teeth. Based on current studies and studies that will be needed in the future, we can anticipate development of scaffolds, homogenous and xenogenous tooth bone grafts, and dental restorative materials using extracted teeth.

Clinical study of graft materials using autogenous teeth in maxillary sinus augmentation

PURPOSE

The purpose of this study was to evaluate the effectiveness of autogenous tooth bone graft materials.

MATERIALS AND METHODS

Hundred implants in 51 patients were selected, and the patients received maxillary sinus augmentation and implant placement using autogenous tooth graft materials at the Chosun University Dental Hospital and Seoul National University Bundang Hospital between July 2009 and November 2010.

RESULTS

In cases using autogenous tooth bone graft alone, or together with other graft material, the implant survival rate was 96.15%. On histomorphologic examination, autogenous tooth bone graft materials showed gradual resorption and new bone formation through osteoconduction and osteoinduction.

CONCLUSIONS

The results indicated that autogenous tooth bone graft materials are appropriate for use in maxillary sinus augmentation.

A comparison of bone generation capability in rabbits using tooth ash and plaster of Paris with platelet-rich plasma or fibrin sealant

OBJECTIVES

Increased attention has been focused on determining the most efficacious materials for generalized bone grafts. This article presents the results of a histomorphometric analysis of bone healing in the calvaria of rabbits. The study compared the use of a tooth ash and plaster of Paris mixture alone, in association with platelet-rich plasma (PRP), and in association with fibrin sealant.

STUDY DESIGN

Twelve rabbits were divided into control (group 1) and experimental groups (groups 2, 3, and 4). Group 1 was maintained as an unfilled control, and tooth ash and plaster of Paris were used in group 2, tooth ash and plaster of Paris with PRP were used in group 3, and tooth ash and plaster of Paris with fibrin sealant (Tissucol Duo Quick) were used in group 4. One-half of the animals were killed after 4 weeks, and the rest were killed after 8 weeks. Bone samples were taken from the defect areas, and newly formed bone was analyzed histomorphometrically.

RESULTS

The rate of new bone formation in groups 2, 3, and 4 was significantly higher than the rate in the control group. The rate of new bone formation in groups 3 and 4 was higher than the rate in group 2, but the difference was not statistically significant.

CONCLUSION

The concomitant use of PRP or fibrin sealant with tooth ash and plaster of Paris graft materials may have a positive effect on bone healing.

Development of a novel bone grafting material using autogenous teeth

We developed a novel bone grafting material that incorporates autogenous teeth (AutoBT), and provided the basis for its clinical application. AutoBT contains organic and inorganic mineral components and is prepared from autogenous grafting material, thus eliminating the risk of an immune reaction that may lead to rejection. AutoBT was used at the time of implant placement, simultaneously with osteoinduction surgery, and excellent bony healing by osteoinduction and osteoconduction was confirmed.

Effect of Tisseel on bone healing with particulate dentin and plaster of Paris mixture

OBJECTIVES

The purpose of this study was to evaluate the effect of Tisseel on the early healing of bone defects in the skulls of rats.

STUDY DESIGN

Forty-eight rats were randomly assigned to 4 groups, and each group was further divided into 3 subgroups which were examined at 4 and 8 weeks after the defects were filled. The 4 different groups were animals containing: no graft (group 1); particulate dentin and plaster of Paris mixture graft (group 2); Tisseel and particulate dentin and plaster of Paris mixture graft (group 3); and Tisseel graft (group 4). After killing the animals at 4 and 8 weeks after surgery, all implant blocks were prepared for histologic sections and histomorphometric analysis.

RESULTS

The overall new bone formation was significantly different between the 4-week samples and the 8-week samples. Significant differences between groups 1 and 2, groups 1 and 3, groups 1 and 4, groups 2 and 4, and groups 3 and 4 were observed at 4 weeks after surgery. At 8 weeks after surgery, significant differences between groups 1 and 2, groups 1 and 3, groups 1 and 4, and groups 2 and 4 were observed. As expected, effective bone formation was observed when the defects were filled with either particulate dentin, Tisseel, or particulate dentin-Tisseel combination. It was also observed from this study that particulate dentin is especially effective, followed by the particulate dentin-Tisseel combination and Tisseel.

CONCLUSION

It was concluded that the use of Tisseel may be an alternative therapy for regenerating bone in defects when used in combination with particulate dentin.

Effects of decortication in the treatment of bone defect around particulate dentin-coated implants: an experimental pilot study

OBJECTIVES

The purpose of this study was to evaluate the effects of decortication during bone grafting in defect areas surrounding particulate dentin-coated implants.

STUDY DESIGN

Six dogs were randomly assigned to 3 groups, and each group was further divided into 2 subgroups. The subgroups consisted of dogs that received particulate dentin-coated implants after 4 or 8 weeks. The defects were treated as follows: control group, unfilled defect; experimental group 1, defect filled with Tutoplast without decortication; experimental group 2, defect filled with Tutoplast with decortication. Histologic sections and histomorphometric analysis were obtained 4 and 8 weeks after surgery.

RESULTS

Compared to the 4-week subgroup, statistically significant new bone formation was observed in the 8-week subgroup. In the 4-week subgroup, the area of new bone formation was larger in the group that underwent cortical bone perforation with bone grafting; however, no significant difference was detected within the 8-week subgroup.

CONCLUSION

According to these results, decortication increases early bone formation after implant placement.

Studies on dentin grafts to bone defects in rabbit tibia and mandible; development of an experimental model

BACKGROUND AND AIM

Dentin contains bone morphogenic protein which is important in bone induction and dentin can act as a slow releasing carrier. This property may possibly be used as an alternative or supplement to bone grafting to defective areas after trauma prior to treatment with osseointegrated implants. Hence, the objective of this study was to investigate if dentin can be used as a graft in bone defects in an experimental rabbit model.

MATERIALS AND METHODS

Eight New Zealand White Rabbits were used to prepare bone cavities either in the angle of the mandible or tibia. Six of the eight tibial and six of the eight mandibular bone defects were filled with dentin blocks from human premolars which were extracted for orthodontic treatment. Two mandibular and two tibial bone cavities were used as controls and all the rabbits were sacrificed after 3 months. Radiographic and histological examinations were performed.

RESULTS

There was a difference in healing pattern between the mandibular and tibial defects. In the mandible, the dentin blocks were resorbed to a larger extent and more often surrounded by fibrous tissue, probably due to the fact that the dentin blocks were mobile because of the thin mandibles and muscular activity in that area. Only some dentin blocks were ankylosed with the mandibular bone. In the tibia however, all dentin blocks were fused to bone over a large area. Osseous replacement resorption was seen. In control cavities, bone formation was seen but was never complete. No signs of inflammatory changes were seen in any fused grafts.

CONCLUSIONS

Dentin grafts have a potential to be incorporated in bone without inflammation and can be used as bone inducer and later replaced by bone. Thus, rabbit tibia served as a better model for further studies of this phenomenon when compared to the mandible.

Bone Regeneration Using B-Tricalcium Phosphate in a Calcium Sulfate Matrix

The aim of the study was the histomorphometric comparison of the osteogenic potential of β-tricalcium phosphate (β-TCP) alone or in a calcium sulfate matrix. Three round defects, 10 mm (diameter) × 5 mm (depth), were created on each iliac crest of 4 dogs. The defects were divided into 3 groups. Ten defects were filled with β-TCP in a calcium sulfate (CS) matrix (Fortoss Vital; group A), 10 defects were filled with β-TCP alone (Fortoss Resorb; group B), and 4 defects were left ungrafted to heal spontaneously (group C). All defects were left to heal for 4 months without the use of a barrier membrane. Histologic evaluation and morphometric analysis of undecalcified slides was performed using the areas of regenerated bone and graft remnants. All sites exhibited uneventful healing. In group A sites (β-TCP/CS), complete bone formation was observed in all specimens, graft granules dominated the area, and a thin bridge of cortical bone was covering the defect. Group B (β-TCP) defects were partially filled with new bone, the graft particles still dominated the area, while the outer cortex was not restored. In the ungrafted sites (group C), incomplete new bone formation was observed. The outer dense cortical layer was restored in a lower level, near the base of the defect. The statistical analysis revealed that the mean percentage of new bone regeneration in group A was higher than in group B (49.38% and 40.31%, respectively). A statistically significant difference existed between the 2 groups. The beta-TCP/CS group exhibited significantly higher new bone regeneration according to a marginal probability value (P = .004 &lt; .05). The use of β-TCP in a CS matrix produced significantly more vital new bone fill and preserved bone dimensions compared with the use of β-TCP alone.

Finite element analysis of different bone substitutes in the bone defects around dental implants

PURPOSE

To evaluate the distribution of stress and strain for the evaluation of implant and graft stability at each stage before stabilization of the graft is achieved after implantation was performed.

MATERIALS AND METHODS

Dembone (Pacific Coast Tissue Bank, Los Angeles, CA), Bio-Oss (Geistlich Pharma, Wolhusen, Switzerland), particulate dentin, and plaster of Paris were used to fill bone defects. The distribution of stress was compared in the mandible and maxilla, between vertical load and load applied at 30 degrees angle, and according to time, with 3 different graft materials.

RESULTS

Stress occurred more when it was applied at an angle, rather than applied vertically. Stress was relatively high immediately after implantation, and particulate dentin-plaster of Paris showed larger mechanical properties and lower stress distribution overall. The largest stress distribution was shown when stress was applied at an angle when demineralized freeze-dried bone was used. The pattern of stress distribution was different according to differences in the mechanical properties of implants.

CONCLUSION

Caution is needed not to apply stress at an angle immediately after implantation. Differences of stress were reduced with time as the implant became stabilized.

Guided Tissue Regeneration of the Mixture of Human Tooth-Ash and Plaster of Paris in Dogs

This study evaluated the efficacy of periodontal tissue regeneration using guided tissue regeneration (GTR) with a mixture of tooth ash and plaster as a bone substitute material in the treatment of class II furcation defects in dogs. GTR was performed at the site of a surgically formed mandibular premolar bifurcation area in dogs. Four adult dogs were used in the animal study. The animals were in a good periodontal state without any systemic disease. A resorbable membrane (Bio-Gide®, Swiss) and bone graft material using a mixture of tooth ash and plaster were used to examine the biological activity. The defect in the control group was filled a Bio-Gide® only. For the experimental group, the defects were filled with a mixture of tooth ash and plaster and covered by a Bio-Gide®. Oral rinsing with 0.12% chlorhexidine was performed twice a day for 2 weeks. In control group, new bone formation was observed adjacent to the preexisting bone. Soft tissue ingrowth was also noted. In experimental group, new lamellar type trabecular bone formation as well as centum and PDL regeneration was observed in the base of the infrabony pocket. More bone regeneration would be expected when GTR is performed using a mixture of human tooth-ash and plaster of Paris as a bone graft material.

No local recurrence of enchondroma after curettage and plaster filling

INTRODUCTION

The most common treatment of enchondromas is curettage (with or without adjuvant therapy) followed by cancellous bone grafting. To avoid donor-site morbidity of the iliac crest, we applied plaster of Paris as a bone defect filler after curettage of enchondromas.

MATERIALS AND METHODS

We treated 19 enchondromas of the hand and foot in 19 patients (mean age 40 years, range 21-79 years) with curettage and filling of the cavity with sterile plaster of Paris (calcium sulphate/phosphate) tablets.

RESULTS

The diagnosis was histologically confirmed in all cases. After a mean follow-up of 53 months (range 15-139 months), the mean functional Muskuloskeletal Tumor Society Score was 29.1 points (97%; range 28-30). There were no local recurrences although adjuvant therapy was not utilized.

CONCLUSION

Plaster of Paris appears safe and effective as a bone-filling substance after curettage of enchondroma.

Effects on bone formation in ovariectomized rats after implantation of tooth ash and plaster of Paris mixture

PURPOSE

Our goal was to report on tooth ash and plaster of Paris mixture in bone defects in an ovariectomized rat osteoporosis model.

MATERIALS AND METHODS

Sixty rats were randomly assigned to 4 groups and each group was further divided into 3 subgroups: 4, 8, and 16 weeks after implantation. The defect was filled with different grafting conditions as follows: group 1, ovariectomy and nongraft group; group 2, ovariectomy and tooth ash-plaster graft group; group 3, nonovariectomy and nongraft group; and group 4, nonovariectomy and tooth ash-plaster graft group. Histologic sections and histomorphometric analysis of defects were obtained 4, 8, and 16 weeks after surgery.

RESULTS

For the 4-week ovariectomy group, there was significantly greater bone formation in tooth ash-plaster group compared with the nongraft group. In the nonovariectomy group, the tooth ash-plaster group also showed better bone formation than the nongraft group. However, there was no statistical significance. In both the ovariectomy and nonovariectomy groups, a significant increase in bone formation was observed according to the elapse of time. The nonovariectomy group showed increased new bone formation compared with the ovariectomy group, with the tooth ash-plaster group showing statistical significance in each subgroup (P =.048).

CONCLUSIONS

Ovariectomy acts as a negative factor in new bone formation. For a critical size bony defect, the tooth ash-plaster treatment of the osseous defect produces more stable, effective, and rapid new bone formation.

Combined implantation of particulate dentine, plaster of Paris, and a bone xenograft (Bio-Oss) for bone regeneration in rats

The purpose of this study is to assess the combination of particulate dentine and plaster as bone substitute material in calvarial bone defects in rats, and to compare it with a bone xenograft (Bio-Oss).

MATERIAL AND METHODS

Forty rats were assigned randomly to five groups and each group was further divided into two subgroups, 8 and 16 weeks after implantation. The defect was filled with different graft materials in each group: Group 1, defects were filled with particulate dentine and plaster using a 2:1 ratio; Group 2, defects were filled with particulate dentine; plaster, and Bio-Oss using a 2:1:1 ratio; Group 3, defects were filled with plaster and Bio-Oss using a 1:1 ratio; Group 4, defects were filled with Bio-Oss only; and Group 5, untreated control defects. Histological sections and histomorphometric analysis of defects were obtained at 8 and 16 weeks postoperatively.

RESULTS

New bone formation was highest in Group 4, followed by Group 3, than Group 2, Group 1, and finally the control group.

CONCLUSION

The combination of particulate dentine and plaster is an alternative bone substitute, although it is less effective than Bio-Oss.