Palatal Osseous Choristoma.

Osseous choristoma of soft tissue in the oral cavity is rare. The choristoma is a tumor-like mass of normal cells in an abnormal location. In this report, a case of osseous choristoma of the palate in a 37-year-old male patient was reported. Approximately 6 × 5 mm pedunculated healthy colored and hard mass was observed in the median palate. The mass was surgically removed. Microscopic examination of the hematoxylin and eosin-stained sections of the mass revealed that a dense lamellar bone nodule was surrounded by fibrous connective tissue under the squamous epithelium. Immunohistochemical analysis revealed that the mass was negative for S-100 protein, cytokeratin, and epithelial membrane antigens. According to these findings, the final pathologic diagnosis confirmed that the mass was an osseous choristoma.

Non-osteoporotic women with low-trauma fracture present altered birefringence in cortical bone.

Areal bone mineral density (BMD) by DXA, although an important index, does not accurately assess risk of fragility fracture. Another bone structural parameter, the orientation of type I collagen, is known to add to risk determination, independently of BMD. Accordingly, we investigated the Haversian systems of transiliac crest biopsies from non-osteoporotic women with low-trauma fractures, matched to healthy women without fracture by age and BMD. We employed circularly polarized light (CPL) microscopy because 1) each of the extinct and bright birefringent signals of CPL corresponds to a specific collagen arrangement; and 2) CPL can employ magnification suitable to provide data, of manageable size, from the whole cortical component of a section of biopsy. Under CPL, the coaxial layers of osteons, called lamellae, appear either birefringent extinct or bright. On a section transverse to the Haversian system, the extinct lamella comprises mainly collagen forming small angles, and the bright lamella comprises mainly collagen forming large angles, relative to the general orientation of the Haversian system. We performed semi-automatic morphometry for birefringent and structural parameters for which we computed intra- and inter-observer errors. The statistical analysis used a linear mixed model to compare fracturing and non-fracturing groups while addressing pairing of fracturing and non-fracturing subjects, and linear regression to assess differences between matched subjects. We found significant reduction in 1) lamellar width and area for extinct lamella and bright lamella; 2) percentage of extinct birefringence in osteons, and 3) single osteon area; in the fracturing group; and in lamellar width in the fracturing subject of all pairs. Our results evidence the need to investigate, in a larger sample of subjects, the distribution of collagen orientation as a parameter diagnostic of increased fracture risk.

Leukocyte-platelet-rich plasma diminishes bone matrix deposition in rat calvaria treated with autograft due to simultaneous increase in immunohistochemical expression of Indian Hedgehog, transforming growth factor-ß, and parathyroid-1 receptor.

PURPOSE: This study evaluated the immunohistochemical presence of Indian Hedgehog (IHH), transforming growth factor-ß (TGF-ß), and parathyroid-1 receptor (PTH1R) in calvaria bone repair, and compared these results with the histological bone matrix features in defects treated with autograft in the presence or absence of L-PRP. MATERIAL AND METHODS: An artificial bone defect measuring 5 × 1 mm was produced in the calvaria of 28 Wistar rats. Randomly the defects were treated with autograft and autograft mixed with L-PRP. The animals were euthanized at 15 and 40 days post-surgery. Data were analyzed by Student-Newman-Keuls test (p ≤ .05) for immunohistochemical interpretation. RESULTS: The results revealed that the histological characteristic of bone matrix deposited in the defect was different in the defects treated with L-PRP. The group that received only the autograft demonstrated larger haversian bone matrix deposited, whereas the group that received autograft mixed with L-PRP revealed trabecular bone deposition. These results coincided with significantly higher immunopositivity for IHH, TGF-ß1, and PTH1R in the L-PRP group. CONCLUSION: These results suggest that L-PRP altered the biological characteristic of the autograft, increasing the bone cells IHH+ but inducing a trabecular bone associated with intense quantities of TGF-ß and PTH1R.

Twelve months of voluntary heavy alcohol consumption in male rhesus macaques suppresses intracortical bone remodeling.

Chronic heavy alcohol consumption is a risk factor for cortical bone fractures in males. The increase in fracture risk may be due, in part, to reduced bone quality. Intracortical (osteonal) bone remodeling is the principle mechanism for maintaining cortical bone quality. However, it is not clear how alcohol abuse impacts intracortical bone remodeling. This study investigated the effects of long-duration heavy alcohol consumption on intracortical bone remodeling in a non-human primate model. Following a 4-month induction period, male rhesus macaques (Macaca mulatta, n=21) were allowed to voluntarily self-administer water or alcohol (4% ethanol w/v) for 22h/d, 7 d/wk for 12months. Control monkeys (n=13) received water and an isocaloric maltose-dextrin solution. Tetracycline hydrochloride was administered orally 17 and 3days prior to sacrifice for determination of active mineralization sites. Animals in the alcohol group consumed 2.7±0.2g alcohol/kg/d (mean±SE) during the 12months of self-administration, resulting in a mean daily blood alcohol concentration of 77±9mg/dl from samples taken at 7h after the start of a daily session. However, blood alcohol concentration varied widely from day to day, with peak levels exceeding 250mg/dl, modeling a binge-drinking pattern of alcohol consumption. The skeletal response to alcohol was determined by densitometry, microcomputed tomography and histomorphometry. Significant differences in tibial bone mineral content, bone mineral density, and cortical bone architecture (cross-sectional volume, cortical volume, marrow volume, cortical thickness, and polar moment of inertia) in the tibial diaphysis were not detected with treatment. However, cortical porosity was lower (1.8±0.5 % versus 0.6±0.1 %, p=0.021) and labeled osteon density was lower (0.41±0.2/mm(2)versus 0.04±0.01/mm(2), p<0.003) in alcohol-consuming monkeys compared to controls, indicating a reduced rate of intracortical bone remodeling. In concordance, plasma CTx was lower (2.5±0.3ng/ml versus 1.7±0.1ng/ml, p=0.028) in the alcohol group. These results suggest that chronic heavy alcohol consumption may negatively impact bone health, in part, by suppressing intracortical bone remodeling.

Bio-Oss(®) for delayed osseointegration of implants in dogs: a histological study.

We evaluated the effects of Bio-Oss® (a natural bone substitute derived from the mineral portion of bovine bone) on delayed osseointegration of implants. The bilateral third and fourth mandibular premolars of 4 adult, healthy, male and female dogs were extracted. We randomly selected 2 extraction sockets in each dog to be filled with Bio-Oss® (the experimental group); the other 2 extraction sockets, which were not treated, served as controls. Dental implants were inserted into the alveolar bone of the experimental group and the control group 3 months after insertion of the Bio-Oss®. The osteogenic activity in the bone around the implants was assessed by evaluating the histological morphology and estimating histomorphometric variables at 3 and 6 months after delayed implantation. After 3 months, Goldner's trichrome staining analysis showed that the rate of content between the bone and the implant and the mineralised area of bone around the implant were significantly higher in the experimental group (76%(9%) and 69.5% (9.6%), respectively) than those in the control group (56.1% (8.2%) and 52.8% (7.3%), respectively, p=0.003 and 0.000). However, the 2 groups did not differ significantly at 6 months. Fluorescence microscopy showed that the mean rates of mineralisation of the bony tissue around the implant in the experimental group at months 3 and 6 were 6.8 (0.4) µm and 8.4 (0.8) µm, respectively, which were significantly higher than those in the control group (p=0.000 and 0.03). These data indicate that putting Bio-Oss® into the extraction sockets can promote osseointegration after delayed implantation, and may be a promising option for clinical use.

Osteo-radio-necrosis (ORN) and bisphosphonate-related osteonecrosis of the jaws (BRONJ): the histopathological differences under the clinical similarities.

OBJECTIVES: Both osteoradionecrosis (ORN) and bisphosphonate associated osteonecrosis of the jaws (BRONJ) present clinically as regions of exposed necrotic bone. The study aimed to demonstrate the histopathological differences behind the observed clinical similarities. STUDY DESIGN: Ten ORN specimens and ten BRONJ specimens were used, as well as ten samples of normal mandibular bone as control. Two bone-specific stainings were used, i.e. Sirius Red for the study of the relative presence of collagen types I and III and toluidine blue for the study the osteon density. RESULTS: The Red Green Blue (RGB)-analysis of the specimens stained with Sirius Red identified significant differences between the chromatic patterns observed in bone preparations of patients suffering from ORN when compared to both BRONJ and control samples. Moreover, the osteon density of the BRONJ samples was significantly lower when compared to ORN and normal bone samples. CONCLUSIONS: The demonstrated differences in the bone architecture and in the bone collagen content between the two pathological conditions most likely reflect underlying pathophysiological differences.

Atypical mature bone in the otosclerotic otic capsule as the differentiated zone of an invasive osseous neoplasm.

CONCLUSION: A large proportion of the mature otic capsule bone in cases of otosclerosis lies in plaques in direct contiguity with active otosclerosis and, because it shows significant structural defects, it should be regarded as part of the otosclerotic process. These appearances support our previously described suggestion that otosclerosis is an invasive osseous neoplasm, the mature atypical bone representing differentiation of earlier-formed invasive neoplastic osseous tissue. OBJECTIVES: We sought structural features in differentiated bone within the otic capsules of cases of otosclerosis that might indicate a relation to the underlying disease process. METHODS: Fifty temporal bones from 42 adult patients with otosclerosis were processed into stained histological sections and the appearance of the otic capsule was compared with that of the same tissue, processed in the same way, in 10 cases that did not show otosclerosis. RESULTS: In the cochlear otic capsules of otosclerotic temporal bones, when traced back along the otosclerotic plaque from the invasive front, atypical shapes and arrangements of osteons were seen, often with otospongiosis (severe dilatation of multiple Volkmann's canals), culminating in larger differentiated osteons with irregularities in structure. In the medial region of the otosclerotic cochlear otic capsule, at a similar position to that where giant normal osteons are present in the normal temporal bone, differentiated, giant abnormal osteons were seen. In the otosclerotic vestibular otic capsule there were changes similar to those of the otosclerotic cochlea (apart from the giant osteons) and many osteons composed of clusters of atypical osteoblast-like cells around highly atypical Volkmann's canals.

Alveolar ridge preservation using resorbable bioactive ceramic composite: a histological study.

PURPOSE: The purpose of this study was to histologically evaluate newly generated vital bone using porous granules of bioactive and resorbable silica-calcium phosphate nanocomposite (SCPC) in extraction sockets. MATERIAL AND METHODS: Six patients with a non-restorable maxillary central incisor requiring extraction followed by implant placement participated in the study. Extraction sockets were grafted with granules of SCPC. After 6 months, a bone core sample was retrieved from the center of the healed socket for histologic analysis, and dental implants were placed. Alveolar bone width was clinically assessed immediately after tooth extraction and 6 months after bone grafting, at the time of implant placement. Alveolar bone height was radiographically assessed immediately after tooth extraction and 6 months after extraction. RESULTS: Histomorphometric analyses of sockets grafted with SCPC for 6 months revealed 46.8% +/- 14% new vital bone and 2.5% +/- 1.5% graft material remnants. In these sockets, the mean bone height resorption over the 6-month period of healing was 1.6 mm +/- 1.5 mm. The mean bone width resorption of 2 mm +/- 0.7 mm was found at the bone crest. CONCLUSION: The results of this study suggest that SCPC graft material reduces the amount of change in alveolar ridge dimensions after tooth extraction and facilitates the regeneration of new vital bone.

A preliminary study on the application of bone marrow stromal cell sheet on the formation of functional tissue-engineered bone in dogs.

PURPOSE: The aim of this study was to construct functional tissue-engineered bone in dogs using cell sheet engineering, a new technique to gain and transfer seed cells. MATERIALS AND METHODS: Demineralized bone matrixes, prepared from homologous bone, were coated with recombinant human bone morphogenetic protein-2. Bone marrow stromal cells (BMSCs) were isolated and subcultured. Osteogenic-induced BMSCs were incubated in a temperature-responsive culture dish to form the BMSC sheet. The complex of demineralized bone matrix, recombinant human bone morphogenetic protein-2, and BMSCs wrapped with BMSC sheets was implanted around the blood vessels of the latissimus dorsi muscle in the experimental side, and the same complex without BMSC sheets was implanted around the blood vessels of the latissimus dorsi muscle on the other side as a control. At 4, 8, 12, and 16 weeks after implantation, the implants were removed for radiographic evaluation, descriptive histologic observation, and histologic quantitative analysis. RESULTS: Radiographic analysis showed that the optical density of the tissue-engineered bone on the 2 sides increased with time. However, the optical density of the experimental side was significantly greater than that of the control side at the same points. Sixteen weeks after implantation, mature lamellar bone was formed in the experimental side, with red bone marrow in the bone marrow cavity. In contrast, the control side exhibited significantly less lamellar bone. Histologic quantitative analysis showed that the experimental side exhibited significantly more bone per area compared with the control side. CONCLUSION: BMSC sheet engineering may be useful to construct functional tissue-engineered bone.

Effect of xenograft (ABBM) particle size on vital bone formation following maxillary sinus augmentation: a multicenter, randomized, controlled, clinical histomorphometric trial.

The purpose of this study was a histomorphometric comparison of vital bone formation following maxillary sinus augmentation with two different particle sizes of anorganic bovine bone matrix (ABBM). Bilateral sinus floor augmentations were performed in 13 patients. Trephine bone cores were taken from the lateral window areas of 11 patients 6 to 8 months after augmentation for histologic and histomorphometric analysis. Bone samples from both the large and small particle size groups showed evidence of vital bone formation similar to that seen in previous studies, confirming the osteoconductivity of ABBM. Significant bone bridging was seen creating new trabeculae composed of the newly formed bone and residual ABBM particles. Histologic evaluation revealed the newly formed bone to be mostly woven bone with some remodeling to lamellar bone. Osteocytes were seen within the newly formed bone as well as osteoblast seams with recently formed osteoid. Isolated osteoclasts were observed on the ABBM surfaces. Vital bone formation (primary outcome measure) was more extensive in the large particle grafts compared with the small particle grafts (26.77% ± 9.63% vs 18.77% ± 4.74%, respectively). The histologic results reaffirm the osteoconductive ability of ABBM when used as the sole grafting material in maxillary sinus augmentation. The histomorphometric results at 6 to 8 months revealed a statistically significant increase (P = .02) in vital bone formation when the larger particle size was used. Additional studies should be performed to confirm these results.

The bone lamina technique: a novel approach for lateral ridge augmentation--a case series.

The goal of this case series is to present a novel treatment approach for lateral ridge augmentation. Four systemically healthy patients (aged 48 to 59 years) with inadequate dental alveolar ridge widths were selected for inclusion. All ridge defects were augmented using a xenogeneic cortical bone shield in combination with particulated bone substitutes and a thin collagen barrier. At baseline and after 6 months, digital cone beam computed tomography scans were performed. Biopsy specimens were harvested at reentry surgery and processed for histologic analysis. The results revealed a sufficient amount of bone structure for implant placement without additional augmentation procedures. The histologic analysis demonstrated that new bone formation had taken place and the bone shield had resorbed entirely. This case series indicates that the bone lamina technique has the biologic and mechanical properties to successfully achieve hard tissue augmentation of deficient ridges.

Piezoelectric device vs. conventional rotative instruments in impacted third molar surgery: relationships between surgical difficulty and postoperative pain with histological evaluations.

PURPOSE: To investigate and compare the influence of surgical difficulty on postoperative pain after treatment of impacted mandibular third molars by rotatory osteotomy or Piezoelectric surgery. MATERIALS AND METHODS: A prospective, randomized, split-mouth study was performed of 52 patients with bilateral and symmetrically oriented impacted mandibular third molars, who were surgically treated using a burr (Group A) on one random side of the lower jaw and a Piezoelectric device (Group B) on the contralateral side. Surgical difficulty was evaluated using a modified version of the Parant scale to categorize "simple extractions" and "complex extractions". Primary outcome parameters were the comparison of the postoperative pain evaluation rated on the Visual Analogue Scale from day 0 to day 6 postsurgery, and the assessment of differences in surgery time between the groups. Bone biopsies were taken during surgery to assess differences in bone tissue damage levels between the two different techniques. RESULTS: In "complex extractions" lower pain evaluation and significantly shorter surgery times were recorded when rotatory instruments were used. In "simple extractions", similar surgery times were observed for both techniques, but pain was greatest on the day of surgery when the burr was used. Bone heat osteonecrosis was observed only in the rotatory group and a high level of alkaline phosphatase was noted only in the Piezoelectric group. CONCLUSION: Pain after extraction of a mandibular third molar increases with increased surgical difficulty and especially in longer interventions. The integrity of the bony structure observed after the ultrasonic technique may favour the bone healing process.

Alterations in the osteocyte lacunar-canalicular microenvironment due to estrogen deficiency.

While reduced estrogen levels have been shown to increase bone turnover and induce bone loss, there has been little analysis of the effects of diminished estrogen levels on the lacunar-canalicular porosity that houses the osteocytes. Alterations in the osteocyte lacunar-canalicular microenvironment may affect the osteocyte's ability to sense and translate mechanical signals, possibly contributing to bone degradation during osteoporosis. To investigate whether reduced estrogen levels affect the osteocyte microenvironment, this study used high-resolution microscopy techniques to assess the lacunar-canalicular microstructure in the rat ovariectomy (OVX) model of postmenopausal osteoporosis. Confocal microscopy analyses indicated that OVX rats had a larger effective lacunar-canalicular porosity surrounding osteocytes in both cortical and cancellous bone from the proximal tibial metaphysis, with little change in cortical bone from the diaphysis or cancellous bone from the epiphysis. The increase in the effective lacunar-canalicular porosity in the tibial metaphysis was not due to changes in osteocyte lacunar density, lacunar size, or the number of canaliculi per lacuna. Instead, the effective canalicular size measured using a small molecular weight tracer was larger in OVX rats compared to controls. Further analysis using scanning and transmission electron microscopy demonstrated that the larger effective canalicular size in the estrogen-deficient state was due to nanostructural matrix-mineral level differences like loose collagen surrounding osteocyte canaliculi. These matrix-mineral differences were also found in osteocyte lacunae in OVX, but the small surface changes did not significantly increase the effective lacunar size. The alterations in the lacunar-canalicular surface mineral or matrix environment appear to make OVX bone tissue more permeable to small molecules, potentially altering interstitial fluid flow around osteocytes during mechanical loading.

Suppurative osteomyelitis, bisphosphonate induced osteonecrosis, osteoradionecrosis: a blinded histopathologic comparison and its implications for the mechanism of each disease.

Statistically, significant numbers of central bone specimens of suppurative osteomyelitis of the jaws (SOJ), bisphosphonate induced osteonecrosis of the jaws (BIONJ), and osteoradionecrosis of the jaws (ORNJ) were compared. All three evidenced the common finding of necrotic bone with empty osteocytic lacunae, Haversian and Volkmann canals, but each showed a distinctive histopathologic pattern indicating a different disease mechanism and treatment options. Suppurative osteomyelitis was characterized by intense marrow inflammation and marrow vessel thrombosis with retention of viable osteoclasts and periosteum. Bisphosphonate induced osteonecrosis was characterized by an empty marrow space with empty Howship's lacunae and an absence of osteoclasts but viable periosteum. Osteoradionecrosis was characterized by a collagenous hypocellular, hypovascular marrow space and nonviable periosteum. Histologic evidence in SOJ indicates a microorganism provoked intense inflammation and marrow vascular thrombosis creating an environment conducive to continual bacterial proliferation. BIONJ is seen as a non-inflammatory drug toxicity to bone by osteoclastic death leading to over suppression of bone renewal, and ORN as another non-inflammatory condition caused by a high linear energy transfer that impairs or kills numerous cell types in the field of radiation including periosteum, bone, and all soft tissue.

Lateral ridge augmentation using an equine flex bone block infused with recombinant human platelet-derived growth factor BB: a clinical and histologic study.

This paper reports on a patient who underwent horizontal ridge augmentation using recombinant human platelet-derived growth factor BB (rhPDGF-BB) in combination with a collagenate equine block. Ninety days after the first surgery, 8 mm of new bone was noted on a computed tomography scan, and three 5-mm implants were placed. Histology, performed using confocal laser scanning microscopy, showed a large amount of newly formed bone well characterized with osteon and resorption lacunae, which demonstrated the intense bone remodeling. This study supports the use of rhPDGF-BB in combination with allograft blocks.

Histological evaluation of the effect of using growth hormone around immediate dental implants in fresh extraction sockets: an experimental study.

PURPOSE: The aim of this study was to histologically evaluate the effect of using growth hormone (GH) around immediate dental implants in fresh extraction sockets. MATERIALS AND METHODS: Six mongrel dogs had had their lower right and left first premolars extracted. For the right side, the control side, implants were placed immediately. For the left sides, the study side, GH powder was placed in the socket and then immediate implant placement was done. Animals were killed at 2, 6, and 12 weeks after surgery, and histological sections were stained with hematoxylin and eosin, and trichrome stains, and observed under light microscopy for the newly formed bone. RESULTS: Bone formation was obvious in both groups. But in study group, bone density had denser and well-oriented collagen fibers. An increase in bone response was observed with high local administration of GH. In the first phases of bone repair, the osteons were more organized; they were more organized by the 12th week. CONCLUSION: The use of GH powder around dental implants placed immediately in fresh extraction sockets enhanced periimplant bone response.

Radiological and histologic studies of the mandibular cortex of ovariectomized monkeys.

OBJECTIVE: The objective was to study the radiological and histologic changes in the mandibular cortices of ovariectomized monkeys. STUDY DESIGN: Twelve female, adult, Cynomolgus monkeys (Macaca fascicularis) were used. Under anesthesia, 1 group was bilaterally ovariectomized (OVX), and the other (control group) underwent sham surgery. Seventy-six weeks after surgery, the monkeys were humanely killed, their mandibles were excised, and their mandibular inferior cortices (MIC) and adjacent cortices were examined histologically and with panoramic radiographs and micro computed tomography. RESULTS: Striped shadows were seen on the endosteal side of the OVX cortices on panoramic radiographs. Histologic observation revealed many enlarged pores with eroded surfaces and calcein labeling (indicating osteon remodeling) in the OVX cortices. CONCLUSIONS: In the MIC and adjacent cortices of OVX monkeys, enlarged Haversian canals were seen and there were indications of a high rate of bone turnover. The enlarged Haversian canals resulted in striped shadows and unclear endosteal margins on radiographic images.

Ovariectomy stimulates and bisphosphonates inhibit intracortical remodeling in the mouse mandible.

OBJECTIVE: The pathophysiology of osteonecrosis of the jaw (ONJ) is thought to be linked to suppression of intracortical remodeling. The aim of this study was to determine whether mice, which normally do not undergo appreciable amounts of intracortical remodeling, could be stimulated by ovariectomy to remodel within the cortex of the mandible and if bisphosphonates (BPs) would suppress this intracortical remodeling. MATERIAL AND METHODS: Skeletally mature female C3H mice were either ovariectomized (OVX) or SHAM operated and treated with two intravenous doses of zoledronic acid (ZOL, 0.06 mg/kg body weight) or vehicle (VEH). This ZOL dose corresponds to the dose given to patients with cancer on a mg/kg basis, adjusted for body weight. Calcein was administered prior to sacrifice to label active formation sites. Dynamic histomorphometry of the mandible and femur was performed. RESULTS: Vehicle-treated OVX animals had significantly higher (eightfold) intracortical remodeling of the alveolar portion of the mandible compared to sham--this was significantly suppressed by ZOL treatment. At all skeletal sites, overall bone formation rate was lower with ZOL treatment compared to the corresponding VEH group. CONCLUSIONS: Under normal conditions, the level of intracortical remodeling in the mouse mandible is minimal but in C3H mice it can be stimulated to appreciable levels with ovariectomy. Based on this, if the suppression of intracortical remodeling is found to be part of the pathophysiology of ONJ, the ovariectomized C3H mouse could serve as a useful tool for studying this condition.