Human saliva-derived exosomes: comparing methods of isolation

ExoQuick-TC(TM) (EQ), a chemical-based agent designed to precipitate exosomes, was calibrated for use on saliva collected from healthy individuals. The morphological and molecular features of the precipitations were compared with those obtained using the classical, physical-based method of ultracentrifugation (UC). Electron microscopy and immunoelectron microscopy with anti-CD63 showed vesicular nanoparticles surrounded by bi-layered membrane, compatible with exosomes in EQ, similar to that observed with UC. Atomic force microscopy highlighted larger, irregularly shaped/aggregated EQ nanoparticles that contrasted with the single, round-shaped UC nanoparticles. ELISA (performed on 0.5 ml of saliva) revealed a tendency for a higher expression of the specific exosomal markers (CD63, CD9, CD81) in EQ than in UC (p>0.05). ELISA for epithelial growth factor receptor, a non-exosomal-related marker, showed a significantly higher concentration in EQ than in UC (p=0.04). Western blotting of equal total-protein concentrations revealed bands of CD63, CD9 and CD81 in both types of preparations, although they were less pronounced in EQ compared with UC. This may be related to a higher fraction of non-exosomal proteins in EQ. In conclusion, EQ is suitable and efficient for precipitation of salivary exosomes from small volumes of saliva; however, EQ tends to be associated with considerably more biological impurities (non-exosomal-related proteins/microvesicles) as compared with UC.

Fresh-frozen allografts combined with bovine bone mineral enhance bone formation in sinus augmentation

We evaluated histologically, histomorphometrically, and tomographically the effects of the association of fresh-frozen bone allograft (FFB) with bovine bone mineral (BBM) in maxillary sinus floor augmentation. In total, 34 maxillary sinuses from 29 patients, with a mean age of 51.32 (±6.44) years, underwent sinus augmentation. Patients were divided into control and test groups (17 sinuses each). The controls were grafted with allograft bone, and the test group received a combination of FFB and BBM at a 2:1 ratio. After 6 months, bone samples were collected for histological and histomorphometric examinations. The implant survival rates were 93.02% (control group) and 100% (test group) at 6 months after functional loading. Median volumetric reductions of 28.32% (17.05-44.05) and 12.62% (5.65-16.87) were observed for the control and test groups, respectively. Statistically significant histomorphometric differences were found between the control and test groups regarding newly formed bone 12.54% (10.50-13.33) vs. 24.42% (17.62-35.92), p < 0.001, total bone 48.34% (39.03-54.42) vs. 61.32% (50.61-64.96), p = 0.007, and connective tissue 51.66% (45.57-60.97) vs. 39.30% (35.03-49.37), p = 0.007. The addition of BBM to allograft bone in maxillary sinus augmentation resulted in higher percentages of new bone formation and total bone, and permitted implant placement with a low rate of osseointegration failure at the 6-month follow-up.

The clinical characteristics of benign oral mucosal tumors

Objectives: To investigate the clinical characteristics and pre-biopsy provisional diagnoses of benign oral mucosal tumors. Material and Methods: A 10- year retrospective analysis of all benign tumors of the oral mucosa, from a university- affiliated oral and maxillofacial surgery department. Results: 146 benign tumors were included. The mean age was 49.6 years, with an approximately equal gender distribution. The most prevalent tumor types were lipomatous tumors (27.4%), vascular (23.3%), and salivary gland tumors (16.5%). Tongue, labial and buccal mucosa were the most frequently involved sites. The vast majority (98.6%) presented as non-ulcerated masses. Only 2 (1.4%) presented as ulcerated masses. The clinical provisional diagnosis correctly classified lesions as non-malignant in 93.3%. In only 9 (6.7%) suspicion of malignancy was included in the provisional diagnosis. However, benign neoplasia was unsuspected in 42.1% of tumors. These cases were clinically classified as reactive. Conclusions: Benign tumors were most likely to be clinically correctly classified as non-malignant, but even in the setting of experienced oral surgeons, neoplasia was unsuspected in more than 40% of cases. This data strongly supports the need to biopsy every oral mucosal mass, since inaccurate clinical evaluation of the lesion’s biological nature was a frequent event.

Key words:Malignant, benign, reactive, ulcerated mass, non-ulcerated mass, clinical diagnosis.

Maxillary sinus grafting with autograft vs. fresh frozen allograft: a split-mouth histomorphometric study

BACKGROUND

Surgical techniques as sinus floor augmentation have made it possible to increase the bone volume of the posterior maxilla so that implant placement may be feasible. A large variety of bone grafting materials have been utilized for sinus floor augmentation. A good alternative is allograft. Fresh frozen bone is harvested from live or cadaveric donors and then immediately frozen and stored at -80 °C. To date, studies about the effect of fresh frozen bone are scarce.

OBJECTIVE

Evaluation of new bone formation, following maxillary sinus grafting with autograft vs. fresh frozen allograft.

MATERIALS AND METHODS

A split-mouth edentulous design including 15 patients was used. Sinus floor augmentation was carried out using either autogenous bone harvested from the ramus area or fresh frozen bone from allogeneic femoral heads. The choice was determined randomly, using a randomized table. The grafted sinus was left to heal for 6 months. Biopsies were harvested from the lateral wall. The biopsies were used for bone histology and histomorphometric analysis. After collection of the biopsy, dental implants were placed. After a healing period of 6 months, the implants were loaded.

RESULTS

Implant survival, histology, and histomorphometry of sinuses grafted with autogenous or fresh frozen bone were similar. The new bone formation took place predominantly around and in-between particles.

CONCLUSIONS

The findings of the present study support the use of fresh frozen bone allografts for sinus floor augmentation.

[Nutraceuticals in the combat against oral cancer]

Head and neck squamous cell carcinoma (HNSCC), the eighth most common cancer worldwide, accounts for approximately 600,000 new cases per year. The mobile tongue is the most common site for oral cancer and is associated with a poorer survival than other HNSCC sites. Standard therapeutic strategies have failed to significantly improve survival rates that have remained around 50% over the past four decades. In the last decade intense investigations on oral cancer highlighted the mandatory role of the tumor microenvironment (TME), in addition to the genetic aberrations and molecular biology changes within the cancer cells. Furthermore, the molecular crosstalk between cancer cells and TME components (i.e., cancer-associated fibroblasts, inflammatory pro-tumorigenic cells, etc.) has a crucial role in growth, invasion, spread and metastases of the cancer cells and consequently leads to poor prognosis. Recent studies suggest that plant-derived dietary agents nutraceuticals, especially curcumin and green tea, have the advantage to combat both malignant cells and TME components, unlike standard anti-cancer protocols that target only cancer cells. However, due to a very low bioavailability, nutraceuticals do not currently constitute an integral part of these protocols. Ongoing developments in nanotechnology for improved delivery are expected to overcome their challenging pharmacokinetics.

Re-evaluation of common paradigms regarding the clinical appearance of oral mucosal malignancies

PURPOSE

To evaluate the clinical appearance and rate of ulceration of oral mucosal malignancies, and to investigate the accuracy of clinical provisional diagnoses.

METHODS

A 10-year retrospective analysis, which included diagnostic biopsies of malignant tumors of the oral mucosa. The clinical provisional diagnoses were compared with final diagnoses.

RESULTS

Two hundred and twenty-seven oral mucosal malignant tumors were included. Squamous cell carcinoma and its variants accounted for the majority (78%) of all malignant tumors. The most common clinical presentations were non-ulcerated (59.7%) and ulcerated masses (20.4%). Only 11.9% presented as indurate ulcers. The highest ulceration rate of all malignancies was recorded for SCC, with only about half of SCC and its variants ulcerated at the time of biopsy. 31.1% of all malignancies were not clinically suspected to be malignant and did not even include a request to rule out malignancy. There was a better agreement between the clinical provisional diagnoses and microscopic diagnoses in the SCC group than in other types of malignancy (P < 0.001).

CONCLUSION

Within this study sample, non-ulcerated masses rather than indurate ulcers are the most common clinical appearance of oral mucosal malignancies, and even for SCC, that showed the highest ulceration rate at presentation, half were non-ulcerated. Approximately, one-third of oral mucosal malignancies were not suspected to be malignant prior to biopsy. Thus, the level of suspicion currently reserved for mucosal ulcers and ulcerated masses should also be applied to non-ulcerated oral mucosal masses.

Histomorphometric analysis following augmentation of the anterior atrophic maxilla with cancellous bone block allograft

PURPOSE

Grafting with bone blocks may be required to restore the alveolar process in extremely atrophic maxillae prior to implant placement to ensure both function and esthetics. The present study was conducted to histologically and histomorphometrically evaluate the application of allograft cancellous bone blocks for the augmentation of the anterior atrophic maxilla.

MATERIALS AND METHODS

Consecutive patients with severe atrophy in the anterior maxilla underwent augmentation with cancellous bone block allografts. Bony deficiencies of at least 3 mm horizontally and up to 3 mm vertically according to computed tomographic para-axial reconstructions served as inclusion criteria. After 6 months, implants were placed and a cylindric sample core from the graft area was collected. All specimens were prepared for histologic and histomorphometric examination.

RESULTS

Forty patients were included in the study. Eighty-three implants were placed in bone that was augmented with 60 cancellous freeze-dried bone block allografts. The implant survival rate was 98.8%. Mean follow-up was 48 ± 22 months (range, 14 to 82 months). The mean percentage of newly formed bone was 33% ± 18%, that of the residual cancellous block allograft was 26% ± 17%, and marrow and connective tissue comprised 41% ± 2%. Statistically significant histomorphometric differences regarding newly formed bone and residual cancellous block allograft were found between younger (< 40 years) and older (≥ 40 years) patients, respectively. Age did not appear to influence the percentage of marrow and connective tissue.

CONCLUSIONS

Cancellous bone block allograft is biocompatible and osteoconductive, permitting new bone formation following augmentation of extremely atrophic anterior maxillae in a two-stage implant placement procedure. New bone formation was age-dependent.

Post-traumatic implant-supported restoration of the anterior maxillary teeth using cancellous bone block allografts

PURPOSE

To prospectively evaluate the outcome of dental implants placed in the post-traumatic anterior maxilla after ridge augmentation with cancellous freeze-dried block bone allografts.

MATERIALS AND METHODS

Patients presenting with a history of anterior dentoalveolar trauma with bony deficiencies in the sagittal (≥3 mm) and vertical (<3 mm) planes according to computed tomography were included. The recipient sites were reconstructed with cancellous bone block allografts. After 6 months of healing, implants were placed. The primary outcomes of interest were 1) bone measurements taken before grafting, at the time of implant placement, and at stage 2 operations; 2) implant survival; and 3) complications.

RESULTS

The sample was composed of 20 consecutive patients with a mean age of 25 ± 7 years. We used 28 cancellous allogeneic bone blocks, and 31 implants were inserted. Of the 31 implants, 12 were immediately restored. The mean follow-up was 42 ± 15 months. Graft and implant survival rates were 92.8% and 96.8%, respectively. Mean bone gain in the sagittal and vertical planes was 5 ± 0.5 mm horizontally and 2 ± 0.5 mm (P < .001). Successful restoration was achieved in all patients with fixed implant-supported prostheses. Soft tissue complications occurred in 7 patients (35%). Complications after cementation of the crowns were seen in 3 implants (9.6%). All implants remained clinically osseointegrated at the end of the follow-up examination. There was no crestal bone loss around the implants beyond the first implant thread.

CONCLUSION

Cancellous block allograft can be used successfully for post-traumatic implant-supported restoration in the anterior maxilla.

Long-term outcome of cemented versus screw-retained implant-supported partial restorations

PURPOSE

The present study was designed to compare the long-term outcome and complications of cemented versus screw-retained implant restorations in partially edentulous patients.

MATERIALS AND METHODS

Consecutive patients with bilateral partial posterior edentulism comprised the study group. Implants were placed, and cemented or screw-retained restorations were randomly assigned to the patients in a split-mouth design. Follow-up (up to 15 years) examinations were performed every 6 months in the first year and every 12 months in subsequent years. The following parameters were evaluated and recorded at each recall appointment: ceramic fracture, abutment screw loosening, metal frame fracture, Gingival Index, and marginal bone loss.

RESULTS

Thirty-eight patients were treated with 221 implants to support partial prostheses. No implants during the follow-up period (mean follow-up, 66 ± 47 months for screw-retained restorations [range, 18 to 180 months] and 61 ± 40 months for cemented restorations [range, 18 to 159 months]). Ceramic fracture occurred significantly more frequently (P < .001) in screw-retained (38% ± 0.3%) than in cemented (4% ± 0.1%) restorations. Abutment screw loosening occurred statistically significantly more often (P = .001) in screw-retained (32% ± 0.3%) than in cement-retained (9% ± 0.2%) restorations. There were no metal frame fractures in either type of restoration. The mean Gingival Index scores were statistically significantly higher (P < .001) for screw-retained (0.48 ± 0.5) than for cemented (0.09 ± 0.3) restorations. The mean marginal bone loss was statistically significantly higher (P < .001) for screw-retained (1.4 ± 0.6 mm) than for cemented (0.69 ± 0.5 mm) restorations.

CONCLUSION

The long-term outcome of cemented implant-supported restorations was superior to that of screw-retained restorations, both clinically and biologically.

Factors affecting changes in sinus graft height between and above the placed implants

OBJECTIVE

The aim of this study was to compare the radiographic dimensional changes of sinus graft height above and between placed implants, and evaluate the factors effecting these changes with 2 different grafting materials and both combination.

STUDY DESIGN

The study group comprised 42 patients (50 sinus augmentation procedures). Four consecutive panoramic radiographs were evaluated for changes in sinus graft height between and above the placed implants. Factors that may influence graft height reduction were evaluated.

RESULTS

The mean percentage of autogenous bone height reduction was 23% between implants and 13% above the implants. Bovine xenograft showed a mean of 6.5% graft height reduction between implants and 0% above implants. The only 2 parameters that correlated with reduction of graft height above and between the implants were time elapsed from surgery and the type of bone graft. Autogenous bone graft presented significantly more reduction (P = .022), whereas anorganic bovine bone graft had only minor or no changes in height.

CONCLUSION

The most important factor influencing reduction in vertical bone height on the time axis, following sinus augmentation is the grafting material, followed by the presence of a functional implant. Anorganic bovine bone was found superior in graft height maintenance in an up to 10 years of follow-up.

Histomorphometric analysis after maxillary sinus floor augmentation using cancellous bone-block allograft

BACKGROUND

Cancellous bone-block allografts may contribute to improved initial implant stability during sinus augmentation in cases with posterior atrophic maxillary ridge height < or =4 mm. The present study histologically and histomorphometrically evaluates the application of cancellous bone-block allografts for maxillary sinus-floor augmentation.

METHODS

Thirty-one consecutive patients, 16 females and 15 males (age range, 25 to 65 years; mean age: 54 +/- 9 years) underwent sinus augmentation with simultaneous implant placement with cancellous bone-block allografts. After 9 months, a second-stage surgery was performed. The previous window location was determined. A cylindrical sample core was collected. All specimens were prepared for histologic and histomorphometric examinations.

RESULTS

Seventy-two of 76 implants were clinically osseointegrated (94.7%). All patients received a fixed implant-supported prosthesis. The mean t values of newly formed bone, residual cancellous bone-block allograft, marrow and connective tissue were 26.1% +/- 15% (range: 10% to 58%); 24.7% +/- 19.4% (range: 0.6% to 71%), and 49.2% +/- 20.4% (range: 14.9% to 78.9%), respectively. No statistically significant histomorphometric differences regarding newly formed bone were found between genders (27.02% in males versus 25.68% in females; P = 0.446), ages (29.82% in subjects < or =40 years old versus 24.43% in subjects >40 years old; P = 0.293), presence of membrane perforations (25.5% in non-perforated sinuses versus 27.3% in perforated sinuses; P = 0.427), and residual alveolar bone height (25.85% for residual alveolar bone height <2 mm versus 26.48% for residual alveolar bone height of 2 to 4 mm; P = 0.473).

CONCLUSION

The cancellous bone-block allograft is biocompatible and osteoconductive and permits new bone formation in sinus augmentations with simultaneous implant-placement procedures in extremely atrophic posterior maxillae.