Histological characterization of the human masticatory oral mucosa. A histochemical and immunohistochemical study.

BACKGROUND: Histology of human oral mucosa is closely related with its function and anatomical location, and a proper characterization of the human masticatory oral mucosa could be very useful in periodontal pathology. OBJECTIVE: In the present work, we have carried out a comprehensive study in order to determine the main histological features of parakeratinized (POM) and orthokeratinized (OOM) masticatory human oral mucosa using light and electron microscopy. METHODS: To perform this, we have used several histological, histochemical and immunohistochemical methods to detect key markets at the epithelial, basement membrane and connective tissue levels. RESULTS: Our results demonstrated that POM and OOM share many histological similarities, as expected. However, important differences were observed at the epithelial layer of POM, that was significantly thicker than the epithelial layer found in OOM, especially due to a higher number of cells at the stratum spinosum. The expression pattern of CK10 and filaggrin revealed intense signal expression in OOM as compared to POM. Collagen and proteoglycans were more abundant in OOM stroma than in POM. No differences were found for blood vessels and basement membrane. CONCLUSION: These results may contribute to a better understanding of the pathological conditions affecting the human masticatory oral mucosa. In addition, these findings could be useful for the generation of different types of oral mucosa by tissue engineering techniques. RESEARCH HIGHLIGHTS: Microscopical features of parakeratinized and orthokeratinized masticatory human oral mucosa showed important differences at both, epithelial and stromal levels. Parakeratinized masticatory human oral mucosa exert thicker epithelial layer, especially, at the stratum spinosum in comparison to orthokeratinized human oral mucosa. Cytokeratin 10 and filaggrin human epithelial markers were intensively expressed in orthokeratinized masticatory human oral mucosa in comparison to parakeratinized masticatory human oral mucosa. At the stromal level, orthokeratinized masticatory human oral mucosa exhibit higher levels of collagen and proteoglycans than parakeratinized masticatory oral mucosa. The deep knowledge of histological features of masticatory oral mucosa could lead to a better understanding of oral mucosa pathology and advanced treatments.

Usefulness of a Nanostructured Fibrin-Agarose Bone Substitute in a Model of Severely Critical Mandible Bone Defect.

Critical defects of the mandibular bone are very difficult to manage with currently available materials and technology. In the present work, we generated acellular and cellular substitutes for human bone by tissue engineering using nanostructured fibrin-agarose biomaterials, with and without adipose-tissue-derived mesenchymal stem cells differentiated to the osteogenic lineage using inductive media. Then, these substitutes were evaluated in an immunodeficient animal model of severely critical mandibular bone damage in order to assess the potential of the bioartificial tissues to enable bone regeneration. The results showed that the use of a cellular bone substitute was associated with a morpho-functional improvement of maxillofacial structures as compared to negative controls. Analysis of the defect site showed that none of the study groups fully succeeded in generating dense bone tissue at the regeneration area. However, the use of a cellular substitute was able to improve the density of the regenerated tissue (as determined via CT radiodensity) and form isolated islands of bone and cartilage. Histologically, the regenerated bone islands were comparable to control bone for alizarin red and versican staining, and superior to control bone for toluidine blue and osteocalcin in animals grafted with the cellular substitute. Although these results are preliminary, cellular fibrin-agarose bone substitutes show preliminary signs of usefulness in this animal model of severely critical mandibular bone defect.

Long-Term Clinical Study of Implants Placed in Maxillary Sinus Floor Augmentation Using Beta-Tricalcium Phosphate.

INTRODUCTION: The aim of this study was to show the long-term clinical outcomes of implants placed in maxillary sinus floor augmentation (MFSA) using beta-tricalcium phosphate (ß-TCP). PATIENTS AND METHODS: Maxillary patients were diagnosed for MFSA and used beta- ß-TCP. After the lateral sinus surgery, implants were loaded at 6 months with restorations. The clinical follow-up was at 10 years. RESULTS: One hundred and one patients (58 females and 43 males) were treated with MFSA. Twenty-nine patients (28.7%) had a history of periodontitis. Thirty-three patients (32.7%) were smokers. One hundred and twenty-one MFSA, 81 unilateral and 20 bilateral sites, with 234 implants were performed. The average vertical bone height available was 4.92 ± 1.83 mm. The average vertical bone gain obtained was 6.95 ± 2.19 mm following MFSA. The implant cumulative survival rate was 97.2%. Three implants (1.3%) were lost during the healing period. Six implants (2.6%) were lost by peri-implantitis. One hundred and fifteen restorations were placed in the patients. Mean marginal bone loss was 1.93 mm ± 1.03 mm. Six patients (27.3%) showed technical complications. Thirty-six implants (15.3%) in 14 patients (13.9%) were associated with peri-implantitis. CONCLUSIONS: This study indicates that treatment with implant-supported restoration by MFSA using ß-TCP constitutes a successful implant approach.

Generation of a novel model of bioengineered human oral mucosa with increased vascularization potential.

OBJECTIVE: The aim of this study was to generate novel models of bioartificial human oral mucosa with increased vascularization potential for future use as an advanced therapies medicinal product, by using different vascular and mesenchymal stem cell sources. BACKGROUND: Oral mucosa substitutes could contribute to the clinical treatment of complex diseases affecting the oral cavity. Although several models of artificial oral mucosa have been described, biointegration is a major issue that could be favored by the generation of novel substitutes with increased vascularization potential once grafted in vivo. METHODS: Three types of mesenchymal stem cells (MSCs) were obtained from adipose tissue, bone marrow, and dental pulp, and their in vitro potential was evaluated by inducing differentiation to the endothelial lineage using conditioning media. Then, 3D models of human artificial oral mucosa were generated using biocompatible fibrin-agarose biomaterials combined with human oral mucosa fibroblasts and each type of MSC before and after induction to the endothelial lineage, using human umbilical vein endothelial cells (HUVEC) as controls. The vascularization potential of each oral mucosa substitute was assessed in vitro and in vivo in nude mice. RESULTS: In vitro induction of MSCs kept in culture was able to increase the expression of VEGF, CD31, and vWF endothelial markers, especially in bone marrow and dental pulp-MSCs, and numerous proteins with a role in vasculogenesis become overexpressed. Then, in vivo grafting resulted in a significant increase in blood vessels formation at the interface area between the graft and the host tissues, with significantly positive expression of VEGF, CD31, vWF, and CD34 as compared to negative controls, especially when pre-differentiated MSCs derived from bone marrow and dental pulp were used. In addition, a significantly higher number of cells committed to the endothelial lineage expressing the same endothelial markers were found within the bioartificial tissue. CONCLUSION: Our results suggest that the use of pre-differentiated MSCs could contribute to a rapid generation of a vascular network that may favor in vivo biointegration of bioengineered human oral mucosa substitutes.

Transversal Maxillary Distraction in Patients with Cleft Lip and Palate.

OBJECTIVE: The aim of this study is to describe the importance of osteodistraction with transpalatal distractors for treating transversal maxillary hypoplasia in patients with cleft and lip palate. METHODS: The participants were 17 patients (9 females and 8 males) with cleft lip and palate. Among these, 10 presented unilateral cleft lip and palate, 4 bilateral cleft lip and palate, and 3 cleft palate only. RESULTS: All patients experienced a satisfactory palatal expansion and crossbite correction. The mean lengthening was 12.7 mm. The average increase of intercanine distance, intermolar distance, maxillary transverse dimension (MTD), facial transverse dimension (FTD) was 12.16, 8.45, 1.77, and 1.67 mm, respectively. The clinical follow-up was 29.7 months (range: 6-61 months). CONCLUSION: Palatal distraction is a safe and successful alternative for treating maxillary transversal alterations in patients with cleft lip and palate. This technique facilitates the establishment of an adequate transverse dimension of maxillary, and consequently a proper dental occlusion.

Generation of a bioengineered autologous bone substitute for palate repair: an in vivo study in laboratory animals.

We carried out an in vivo study to evaluate the potential usefulness of a novel bioengineered bone substitute for the repair of palate defects in laboratory rabbits, using tissue-engineering methods. Our results showed that the use of a bioengineered bone substitute was associated with more symmetrical palate growth as compared to the controls, and the length and height of the palate were very similar on both sides of the palate, with differences from negative controls 4 months after artificial bone grafting for bone length. The histological analysis revealed that the regenerated bone was well organized and expressed osteocalcin. In contrast, bone corresponding to control animals without tissue grafting was immature, with areas of osteoid tissue and remodelling, as determined by MMP-14 expression. These results suggest that bone substitutes may be a useful strategy to induce the formation of a well-structured palate bone, which could prevent the growth alterations found in cleft palate patients. This opens a door to a future clinical application of these bone substitutes. Copyright © 2015 John Wiley & Sons, Ltd.

Nasoalveolar Molding Therapy for the Treatment of Unilateral Cleft Lip and Palate Improves Nasal Symmetry and Maxillary Alveolar Dimensions.

OBJECTIVE: The aim of this study is to assess the esthetic and morphologic outcomes before surgery using nasoalveolar molding (NAM) therapy in children with unilateral cleft lip and palate. DESIGN: A prospective analysis was performed. SETTING: The study was carried out in the Congenital Malformations Craniofacial and Cleft Lip and Palate Unit, Hospital Virgen de las Nieves, Andalusian Health Service, Granada (Spain). PATIENTS: Twenty consecutively enrolled infants ranging in age from 7 to 30 days with nonsyndromic unilateral cleft lip and palate treated from 2008 to 2012. INTERVENTIONS: All patients were treated with NAM appliances to align the alveolar segments and reduce severity of the nasal deformity. MAIN OUTCOME MEASURE: The extraoral nasal measurements were performed on casts and nasal photographs. The measurements consisted of bialar width (BAW), columellar deviation (CD), cleft nostril height (CNH), cleft nostril width (CNW), non-CNH, non-CNW, and the deviation of the columella to the horizontal line represented by bilateral pupil line (BIA). The authors have made the measurements following Barilla method. Also 2 intraoral measurements were taken. RESULTS: Following NAM the extraoral records showed a statistically significant decrease in CD (P < 0.0001), CNW (P < 0.0001), and BAW (P < 0.001). Furthermore, statistically significant increases in CNH (P < 0.05) and BIA (P < 0.0001) were observed.Following Barilla measurements, the authors have found a high percentage of symmetry in all the nasal measurements after the NAM therapy.Intraoral results showed a statistically significant decrease in the gap between the greater and lesser alveolar segments and a statistically significant increase in maxillary arch width. CONCLUSIONS: Nasoalveolar molding improves nasal symmetry and achieves an improvement of all maxillary alveolar dimensions, increasing alveolar rim width, reducing the size of alveolar cleft gap, and improving shape of the maxillary dental arch. As a consequence of reducing the alveolar and nasal deformities before surgery, it is expected that the primary repair will be easier for the surgeon and more successful.

Usefulness of a bioengineered oral mucosa model for preventing palate bone alterations in rabbits with a mucoperiostial defect.

The use of mucoperiostial flaps during cleft palate surgery is associated with altered palatal bone growth and development. We analyzed the potential usefulness of a bioengineered oral mucosa in an in vivo model of cleft palate. First, a 4 mm palate defect was created in one side of the palate oral mucosa of 3 week-old New Zealand rabbits, and a complete autologous bioengineered oral mucosa (BOM) or acellular fibrin-agarose scaffold (AS) was implanted. No material was implanted in the negative controls (NC), and positive controls were not subjected to palatal defect (PC). Animals were allowed to grow for 6 months and the results were analyzed morphologically (palate mucosa and bone size) and histologically. Results show that palatal mucosa and bone growth and development were significantly altered in NC and AS animals, whereas BOM animals had similar results to PC and the bioengineered oral mucosa was properly integrated in the host palate. The amount and compaction of collagen fibers was similar between BOM and PC, and both groups of animals had comparable contents of proteoglycans and glycoproteins at the palate bone. No differences were found for decorin, osteocalcin and BMP2. The use of bioengineered oral mucosa substitutes is able to improve palate growth and maturation by preventing the alterations found in animals with denuded palate bone. These results support the potential clinical usefulness of BOM substitutes for the treatment of patients with cleft palate and other conditions in which palate mucosa grafts are necessary with consequent bone denudation.