Bone replacement following dental trauma prior to implant surgery--status

New Oral Surgery Materials for Bone Reconstruction-A Comparison of Five Bone Substitute Materials for Dentoalveolar Augmentation

This article presents a comparison of bone replacement materials in terms of their ability to produce living bone image at the place of their implantation. Five bone replacement materials are compared (Osteovit-porous collagen, Cerasorb Foam-collagen scaffolding of synthetic β tricalcium phosphate, Osbone-synthetic hydroxyapatite, Endobone-deproteinized bovine-derived cancellous bone hydroxyapatite, and Cerasorb-synthetic β tricalcium phosphate). Intraoral radiographs are taken immediately after implantation and 12 months later. The texture analysis was performed to assess (texture index, TI) the level of structure chaos (entropy) in relation to the presence of longitudinal elements visible in radiographs (run length emphasis moment). The reference ratio of the chaotic trabecular pattern (Entropy) to the number of longitudinal structures, i.e., trabeculae (LngREmph), is 176:100 (i.e., 1.76 ± 0.28). Radiological homogeneity immediately after the implantation procedure is a result of the similar shape of its particles (Osbone, Endobone and Cerasorb) or radiolucency (Osteovit, Cerasorb Foam). The particles visible in radiographs were similar in the LngREmph parameters applied to the reference bone, but not in the co-occurrence matrix features. The TI for Osteovit during a 12-month follow-up period changed from 1.55 ± 0.26 to 1.48 ± 0.26 (p > 0.05), for Cerasorb Foam from 1.82 ± 0.27 to 1.63 ± 0.24 (p < 0.05), for Osbone from 1.97 ± 0.31 to 1.74 ± 0.30 (p < 0.01), and for Endobone from 1.86 ± 0.25 to 1.84 ± 0.25 (p > 0.05), The observed structure in the radiological image of bone substitute materials containing calcium phosphates obtains the characteristics of a living bone image after twelve months.

Prosthetic, orthodontic and implant-supported rehabilitation of five maxillary anterior teeth with alveolar bone loss

INTRODUCTION

Treatment of maxillofacial injuries is complex and requires the establishment of a comprehensive and accurate diagnosis and correct treatment planning.

OBJECTIVE

The objective of this case report was to describe the re-treatment of a 27-year-old woman who was involved in a severe car accident that resulted in the loss of five anterior teeth and alveolar bone, and whose previous orthodontic and surgical treatments had been unsuccessful.

CASE REPORT

In this case, the space for the missing mandibular molar was reopened to allow for rehabilitation. The positions of the mandibular incisors were improved. The right mandibular canine was moved to the mesial, allowing for correction of the Class II canine relationship on that side, and implants were placed to replace the maxillary anterior teeth.

CONCLUSION

Anterior aesthetic and functional rehabilitation using a multidisciplinary approach was essential to improve the patient's facial aesthetics, to obtain great improvement in function and to achieve occlusal stability after 2 years of follow-up.

Cytocompatibility and biocompatibility of nanostructured carbonated hydroxyapatite spheres for bone repair

Objective

The aim of this study was to investigate the in vitro and in vivo biological responses to nanostructured carbonated hydroxyapatite/calcium alginate (CHA) microspheres used for alveolar bone repair, compared to sintered hydroxyapatite (HA).

Material and Methods

The maxillary central incisors of 45 Wistar rats were extracted, and the dental sockets were filled with HA, CHA, and blood clot (control group) (n=5/period/group). After 7, 21 and 42 days, the samples of bone with the biomaterials were obtained for histological and histomorphometric analysis, and the plasma levels of RANKL and OPG were determined via immunoassay. Statistical analysis was performed by Two-Way ANOVA with post-hoc Tukey test at 95% level of significance.

Results

The CHA and HA microspheres were cytocompatible with both human and murine cells on an in vitro assay. Histological analysis showed the time-dependent increase of newly formed bone in control group characterized by an intense osteoblast activity. In HA and CHA groups, the presence of a slight granulation reaction around the spheres was observed after seven days, which was reduced by the 42^nd day. A considerable amount of newly formed bone was observed surrounding the CHA spheres and the biomaterials particles at 42-day time point compared with HA. Histomorphometric analysis showed a significant increase of newly formed bone in CHA group compared with HA after 21 and 42 days from surgery, moreover, CHA showed almost 2-fold greater biosorption than HA at 42 days (two-way ANOVA, p<0.05) indicating greater biosorption. An increase in the RANKL/OPG ratio was observed in the CHA group on the 7^th day.

Conclusion

CHA spheres were osteoconductive and presented earlier biosorption, inducing early increases in the levels of proteins involved in resorption.

A histomorphometric assessment of collagen-stabilized anorganic bovine bone mineral in maxillary sinus augmentation - a prospective clinical trial

OBJECTIVE

To histomorphometrically compare the use of collagen-stabilized anorganic bovine bone (ABBM-C) (test) to anorganic bovine bone + autogenous bone (ABBM + AB) (control) in maxillary sinus augmentation.

MATERIALS AND METHODS

Forty (n = 40 sinuses) patients underwent sinus augmentation and received either control (20 sinuses) or test bone graft (20 sinuses). Bone samples were harvested from the augmented sinuses 5 months postgrafting. The samples were processed for histomorphometry, which assessed within the primary region of interest (ROI-1), the area fraction of new bone (%NB), graft particle osseointegration (% OI), residual graft (%RG), and soft tissue components (% STM). The same analysis was also carried out in a second region of interest (ROI-2) located in a zone 1 mm proximal to the previous maxillary sinus floor.

RESULTS

In both ROI-1 and ROI-2, the mean % NB, %RG, and %STM in the control group were similar to mean values in the test group. The % OI was significantly greater in the control group (42.0 +/- 26.8) when compared to the test group (19.6 +/- 27.3) in ROI-2 (P < 0.05). No statistically significant differences were seen when ROI-1 and ROI-2 were compared except for improved %OI in ROI-2 in the control group. The mean proportion of lamellar bone to woven bone in the control group (1.22 ± 1.48) was significantly greater than the test group (0.38 ± 0.29) (P < 0.05).

CONCLUSION

ABBM-C exhibited very similar histomorphometric parameters to the composite graft of ABBM + AB. The ABBM + AB group was more mature as indicated by the significantly greater proportion of lamellar bone when compared to the ABBM-C. Improved % OI was seen in the zone proximal to the resident bony floor in the ABBM + AB group. Based on histological assessment, ABBM-C is a suitable bone substitute for the purposes of maxillary sinus augmentation. Its clinical utility may be indicated in cases of sinus membrane perforation and insufficient autogenous bone in the local area.

Chlorhexidine-loaded hydroxyapatite microspheres as an antimicrobial delivery system and its effect on in vivo osteo-conductive properties

Hydroxyapatite (HA) has been investigated as a delivery system for antimicrobial and antibacterial agents to simultaneously stimulate bone regeneration and prevent infection. Despite evidence supporting the bactericidal efficiency of these HA carriers, few studies have focused on the effect of this association on bone regeneration. In this work, we evaluated the physico-chemical properties of hydroxyapatite microspheres loaded with chlorhexidine (CHX) at two different concentrations, 0.9 and 9.1 μgCHX/cm2 HA, and characterized their effects on in vitro osteoblast viability and bone regeneration. Ultraviolet-visible spectroscopy, scanning and transmission electron microscopy associated with energy-dispersive X-ray spectroscopy and electron energy loss spectroscopy were used to characterize the association of CHX and HA nanoparticles. The high CHX loading dose induced formation of organic CHX plate-like aggregates on the HA surface, whereas a Langmuir film was formed at the low CHX surface concentration. Quantitative evaluation of murine osteoblast viability parameters, including adhesion, mitochondrial activity and membrane integrity of cells exposed to HA/CHX extracts, revealed a cytotoxic effect for both loading concentrations. Histomorphological analysis upon implantation into the dorsal connective tissues and calvaria of rats for 7 and 42 days showed that the high CHX concentration induced the infiltration of inflammatory cells, resulting in retarded bone growth. Despite a strong decrease in in vitro cell viability, the low CHX loading dose did not impair the biocompatibility and osteoconductivity of HA during bone repair. These results indicate that high antimicrobial doses may activate a strong local inflammatory response and disrupt the long-term osteoconductive properties of CHX-HA delivery systems.

Use of titanium mesh in lieu of a fixation screw to stabilize an autogenous block graft: a case report

Localized alveolar augmentation is carried out either before, during, or sometimes after implant placement. The placement of autogenous graft as a block or a particulate alone or in combination with an organic bone mineral has been practiced with a great deal of success. The block graft is secured in place with a screw and protected by a membrane. This case report describes the treatment of a female patient with a bucco-lingual bone deficiency grafted with autogenous block and a titanium mesh. Five months later, implant was placed in the grafted area. The definitive prosthesis was cemented 6 months later and followed up for 2 years.

Dentin xenografts to experimental bone defects in rabbit tibia are ankylosed and undergo osseous replacement

PURPOSE

After trauma and losses of teeth, bone augmentation with bone grafts or bone replacement material is sometimes required before implant treatment. The ideal bone replacement material has not yet been characterized. Dentin is known to undergo ankylosis and replacement resorption after replantation of teeth. Dentin has also been shown to contain bone morphogenic protein. These properties may possibly be used making dentin an alternative or supplement to bone grafting to defect areas prior to treatment with osseointegrated implants. The aim of this study was to investigate if dentin is ankylosed and replaced by newly formed bone when transplanted to bone defects.

MATERIALS AND METHODS

Ten New Zealand rabbits were used for the experiment. The rabbits were subjected to surgical exposure and preparation of bone cavities in the tibia bilaterally. Dentin blocks from human premolars extracted for orthodontic reasons were used as grafts. Dentin blocks were inserted in the cavities penetrating into the marrow space in 16 tibias. Four tibias were prepared with the same cavities, but without being subjected to dentin grafting and served as controls. Five rabbits were sacrificed after 3 months and five rabbits after 6 months. Histological processing and evaluation were performed and tissue conditions evaluated. The area of ankylosis was estimated.

RESULTS

All dentin blocks healed with ankylosis in contact with bone without inflammatory reactions. In the cortical regions of the tibia, fusion of bone with dentin was seen in 86% of the dentin surface after 3 months and 98% after 6 months. On the dentin blocks inserted into the marrow space, bone was formed on the dentin block on average covering 51% of the dentin after 3 months and covering 77% after 6 months. Resorption of the dentin was seen to a larger extent after 6 months with osseous replacement in the resorption cavities.

CONCLUSION

Dentin xenografts have a potential to be incorporated in bone without inflammation and gradually resorbed and replaced by new bone.

One-stage surgical approach to rehabilitate severely injured anterior teeth in a young woman

Trauma of the maxillofacial district may cause severe injuries to patients, such as tooth loss or tooth fractures, which can irreversibly compromise aesthetics and function.The aim of this clinical report was to illustrate the possibility of achieving positive aesthetic and functional outcomes in a young patient through a 1-stage surgical approach. In a single stage, the patient underwent extraction of a compromised tooth, insertion of 5 implants, bone and connective grafts, and management of a fresh scar. A satisfied and appeased result from the patient's and clinician's points of view was obtained by means of some clinical tricks, avoiding the patient's stress because of a multiple-stage surgery.