Nada Naaman

Picrosirius Red Staining A Useful Tool to Appraise Collagen Networks in Normal and Pathological Tissues

Specific staining of the extracellular matrix components is especially helpful in studying tissue remodeling, particularly in the case of connective tissue pathologies. As developed by Junqueira and colleagues in 1979, specific staining by Picrosirius red is one of the most important stains to study collagen networks in different tissues. Under polarized light, collagen bundles appear green, red or yellow, and are easily differentiated from the black background, thus allowing for quantitative morphometric analysis. As Junqueira and colleagues point out, many studies use color staining to differentiate collagen bundles and to specify collagen types, yet other studies report that polarized colors only reflect fiber thickness and packing. Using a simple histological example, our study illustrates the inability of Picrosirius red staining to differentiate collagen types, since the absorbed amount of polarized light by this dye strictly depends on the orientation of the collagen bundles.

Comparison of the OHIP-14 and GOHAI as measures of oral health among elderly in Lebanon

BackgroundThe respective abilities of the GOHAI and OHIP-14 to discriminate between aged patients with different levels of oral diseases have rarely been studied in developing countries. The aim of this study was to compare the discriminative abilities of the OHIP-14 and the GOHAI in an elderly Lebanese population, and particularly to identify persons with different masticatory function.MethodsA sample of elderly, aged 65 years or more, living independently was recruited in two primary care offices in Beirut, Lebanon. Data were collected by means of personal interview and clinical examination. The Arabic OHIP-14 and GOHAI questionnaires were used after cultural adaptation for use in Lebanon. The internal consistency, reproducibility and concurrent validity were verified. To test their discriminative abilities, the ADD (GOHAI and OHIP) and SC (GOHAI and OHIP) scores were dichotomized according to the 25th and 75th percentile respectively and logistic regressions were conducted using socio-demographic, clinical and subjective explanatory variables.ResultsTwo hundred and six participants were included; mean age was 72 years and 60% were women. Good psychometric properties were observed for both questionnaires for internal consistency (Cronbach’s alpha>0.88), reproducibility (ICC>0.86) and concurrent validity. Strong correlations were found between GOHAI and OHIP-14 scores but a high prevalence of subjects with no impact was observed using the OHIP-14. Both questionnaires were able to discriminate between participants according to age, perception of temporomandibular joint (TMJ) pain or functional status as represented by the number of dental Functional Units (FU). GOHAI was more discriminant since it identified participants with high dental care needs: high numbers of decayed teeth, low numbers of teeth and socially deprived status.ConclusionsLebanese elderly with high dental care needs and impaired oral health were identified more easily with the GOHAI. These results may guide the choice of dental indicators to use in a national geriatric survey.

The pertinence of oral health indicators in nutritional studies in the elderly

BACKGROUND AND AIM Studies concerning the more appropriate criteria for evaluating oral health in relation to nutrition in the elderly vary greatly. There is a need to identify the most relevant criteria for classifying dental indicators of mastication in nutritional studies, so these indicators may be considered for epidemiological and clinical purposes. The aim of this study was to explore the associations between nutritional deficit and measures of oral health in a group of elderly. METHODS A convenience sample of independent elderly aged 65 years or more attending two primary care clinics in Beirut, Lebanon was selected. Data were collected from a questionnaire including the Mini-Nutritional Assessment (MNA), Geriatric Oral Health Assessment Index (GOHAI) and questions about perception of xerostomia and chewing problems. The oral examinations recorded decayed, missing and filled teeth (DMFT), the prosthetic status and the number of functional units (FU). RESULTS The sample was composed of 121 women (mean age: 71.59 ± 5.97 years) and 80 men (mean age: 72.74 ± 6.98 years). They were allocated to two groups: 85 participants suffering from malnutrition (MNA score < 17, n = 17) or at risk of malnutrition (17 < MNA score < 24, n = 68) and 116 participants with a normal nutritional status (MNA score ≥ 24). Parameters that explain MNA variations were perception of xerostomia (OR = 3.49, 95% CI [1.66-7.34]), number of FU (OR = 2.79, 95% CI [1.49; 5.22]), and GOHAI score (OR = 2.905, 95% CI [1.40; 6.00]). CONCLUSION Further studies exploring factors affecting nutrition in the elderly should take into consideration perception of xerostomia, number of FUs and GOHAI score.

Clinical, histological, and histomorphometrical analysis of maxillary sinus augmentation using inorganic bovine in humans: preliminary results.

The aim of the present study was to evaluate bone formation after maxillary sinus augmentation using bovine bone substitute material Bio-Oss alone by means of clinical, histological, and histomorphometrical examination of human biopsies. Deproteinized bovine bone (DPBB, Bio-Oss) was used to fill cavities after elevation of the sinus mucosa following major sinus pneumatization. Twenty patients with edentulous posterior maxillae were treated with 20 sinus augmentation procedures using a 2-stage technique. Residual lateral maxillary bone height was less than 3 mm. Forty-nine Straumann endosseous implants were used to complete the implant-prosthetic rehabilitation. Forty cylinder-shaped bone biopsies were taken from the augmented maxillary region 8 months after grafting during the second-stage surgery before implant placement. All implants were loaded 3 months after insertion, and no failures were recorded. Histomorphometrical analysis showed an average percentage of newly formed bone of 17.6% (± 2.8%) and a proportion of residual bone substitute material of 29.9% (± 4.9%) of the total biopsy area. Intimate contact between newly formed bone and Bio-Oss was detected along 28.2% (± 6.8%) of the particle surfaces. The results also showed that in all cases, the DPBB granules had been interconnected by bridges of vital newly formed bone. Inorganic bovine bone appears to be biocompatible and osteoconductive, and it can be used with success as a bone substitute in maxillary sinus augmentation procedures.

Pertinent cell population to characterize periodontal disease

The purpose of this in situ study is to quantify the inflammatory cell subsets and the area fraction (AA%) occupied by collagen fibers in human healthy and diseased (four different stages) gingival connective tissue in order to establish a possible correlation between periodontal disease resulting in collagen breakdown and specific inflammatory cell subsets. Paraffin gingival tissue sections from eight healthy controls (group 0), 10 patients with gingivitis (group 1), 10 patients with moderate periodontitis (group 2) and 10 patients with severe periodontitis (group 3) were immunohistochemically investigated using antibodies against CD-45+, CD-3+, CD-8+, CD-20+, CD-68+, and EMA+ (plasma cells). The AA% occupied by gingival collagen fibers significantly decreased from 54.12% in group (0) to 38.58% in group (1), to 31.87% in group (2), and to 25.46% in group (3). In progressive lesions of periodontal disease, CD-3(+) and CD-8+ cell numbers were increased in early stages within the connective tissue, while CD-20+ cell numbers were increased only in late stages. On the other hand, EMA+, CD-68+ and CD-45+ cell numbers were progressively increased from group (0) to group (3). We demonstrated that CD-68+ monocyte/macrophages, CD-45+ leukocyte common antigen and notably EMA+ plasma cells are pertinently correlated with the severity of periodontal disease and related collagen breakdown.

Biotribocorrosion (tribo-electrochemical) characterization of anodized titanium biomaterial containing calcium and phosphorus before and after osteoblastic cell culture

The purpose of this study was to investigate the relationship between the osteoblastic cells behavior and biotribocorrosion phenomena on bioactive titanium (Ti). Ti substrates submitted to bioactive anodic oxidation and etching treatments were cultured up to 28 days with MG63 osteoblast-like cells. Important parameters of in vitro bone-like tissue formation were assessed. Although no major differences were observed between the surfaces topography (both rough) and wettability (both hydrophobic), a significant increase in cell attachment and differentiation was detected on the anodized substrates as product of favorable surface morphology and chemical composition. Alkaline phosphatase production has increased (≈20 nmol/min/mg of protein) on the anodized materials, while phosphate concentration has reached the double of the etched material and calcium production increased (over 20 µg/mL). The mechanical and biological stability of the anodic surfaces were also put to test through biotribocorrosion sliding solicitations, putting in evidence the resistance of the anodic layer and the cells capacity of regeneration after implant degradation. The Ti osteointegration abilities were also confirmed by the development of strong cell-biomaterial bonds at the interface, on both substrates. By combining the biological and mechanical results, the anodized Ti can be considered a viable option for dentistry.

Expression of MMP-2, 9 and 13 in newly formed bone after sinus augmentation using inorganic bovine bone in human

BACKGROUND AND OBJECTIVE The aim of the present study was to analyse the expression of MMP-2, MMP-9 and MMP-13 in newly formed bone following maxillary sinus augmentation using inorganic bovine bone substitute, because these MMPs play a major role in bone remodeling and bone resorption. MATERIAL AND METHODS Deproteinized bovine bone (Bio-Oss(®)) was used to fill cavities after elevating the sinus mucosa. Twenty patients with edentulous posterior maxilla were treated with 20 sinus-augmentation procedures using a two-stage technique. Forty-nine Straumann(®) endosseous implants were used to complete the implant-prosthetic rehabilitation. One cylinder-shaped bone biopsy from each patient was taken from the augmented maxillary region using trephine burs at the second stage of surgery, 8 months after grafting. A biopsy was also taken as a control from the upper molar region from six different patients who did not undergo the sinus procedure. All biopsies were subjected to biochemical analysis and staining for TRAP. RESULTS No implant losses or failures occurred. The large number of TRAP-positive multinucleated osteoclasts in resorption lacunae indicated that the resorption was very active in all grafts, in contrast with the control group. Zymography and western blot analysis demonstrated a significantly increased expression of MMP-2, MMP-9 and MMP-13 in the newly formed bone compared with controls (p < 0.05). CONCLUSION The quantity of osteoclastic cells and the increased expression of proteolytic enzymes suggest that 8 months after grafting, inorganic bovine bone is slowly resorbing and is the site of important remodeling of the newly formed bone by means of resorption and synthesis.

Healing patterns of critical size bony defects in rats after grafting with bone substitutes soaked in recombinant human bone morphogenetic protein-2: histological and histometric evaluation

The aim of the study was to evaluate the effect of different bone substitutes soaked in recombinant human bone morphogenetic protein-2 (rhBMP-2) on the healing of critical size defects in calvarial bone. Defects were created in 24 Sprague Dawley rats. The rhBMP-2 was diluted to obtain a final concentration of 0.2mg/ml. Rats were divided into four groups and treated as follows: in the first group the defect was filled with anorganic bovine bone mineral (ABBM) and rhBMP-2, the second group was treated with freeze-dried bone allograft (FDBA) and rhBMP-2, and the third group was treated with autogenous bone (AUTO). In the control group the defects were left untreated. Animals were killed after 8weeks and calcified histological sections prepared. Histometric measurements showed that mean (SD) bone formation was 4.00 (1.69)mm(2) in the ABBM group, 2.56 (1.06)mm(2) in the FDBA group, and 2.30 (0.34)mm(2) in the AUTO group. The difference between the ABBM group and the other 3 groups was significant (p<0.0001) with a mean bone formation of 0.82 (0.25)mm(2) in the control group. There was no significant difference between the FDBA and the AUTO groups (p=0.96). Within the limits of this study we concluded that the addition of rhBMP-2 to bone substitutes was efficacious in regenerating bone in critical size bone defects in calveria in rats.

Buccal Bone Thickness Overlying Maxillary Anterior Teeth: A Clinical and Radiographic Prospective Human Study.

Objectives:The aim of this work was to measure the facial bone thickness overlying maxillary anterior teeth according to the periodontal biotype, the tooth position, and the bucco-palatal inclination of the tooth. Materials and Methods:CBCTs of 47 patients were included. The periodontal biotype and the bucco-palatal inclination were examined for all maxillary anterior teeth as well as the sagittal tooth position according to the classification of Kan et al. Buccal bone thickness was measured at 4, 6, 8, and 10 mm apical to the cement–enamel junction (CEJ). Results:At 4 mm from the CEJ, mean buccal bone thickness was 1.0 mm for all teeth and it decreased gradually and significantly in apical direction (6, 8, and 10 mm). A thin biotype was associated with a labial plate thickness half that of a thick biotype at all 4 distances from the CEJ. Class IV of Kan et al classification presented the thinnest facial bone (0.32–0.54 mm), whereas Class III demonstrated the thickest one (1.26–2.09 mm) at all distances from the CEJ. At 10 mm from the CEJ, the facial bone thickness increased with the vestibulo-palatal inclination of the tooth. Conclusion:A thin facial bone wall overlies almost all maxillary anterior teeth.

Bone Formation with Deproteinized Bovine Bone Mineral or Biphasic Calcium Phosphate in the Presence of Autologous Platelet Lysate: Comparative Investigation in Rabbit

Bone substitutes alone or supplemented with platelet-derived concentrates are widely used to promote bone regeneration but their potency remains controversial. The aim of this study was, therefore, to compare the regenerative potential of preparations containing autologous platelet lysate (APL) and particles of either deproteinized bovine bone mineral (DBBM) or biphasic calcium phosphate (BCP), two bone substitutes with different resorption patterns. Rabbit APL was prepared by freeze-thawing a platelet suspension. Critical-size defects in rabbit femoral condyle were filled with DBBM or DBBM+APL and BCP or BCP+APL. Rabbits were sacrificed after six weeks and newly formed bone and residual implanted material were evaluated using nondemineralized histology and histomorphometry. New bone was observed around particles of all fillers tested. In the defects filled with BCP, the newly formed bone area was greater (70%; P < 0.001) while the residual material area was lower (60%; P < 0.001) than that observed in those filled with DBBM. New bone and residual material area of defects filled with either APL+DBBM or APL+BCP were similar to those observed in those filled with the material alone. In summary, osteoconductivity and resorption of BCP were greater than those of DBBM, while APL associated with either DBBM or BCP did not have an additional benefit.