Vascular endothelial growth factor behavior in different stages of tooth germ development

BACKGROUND

Scientific studies show a possible influence of intercellular and intracellular proteins (VEGF) on the development of physiological and pathological tissue. VEGF, a key regulator of angiogenesis, it would seem essential to take action during the embryonic development of the dental germ. The purpose of the study is to investigate the importance of the enzymatic activity of VEGF through protein quantification at different stages of tooth germ development.

METHODS

The quantification of VEGF protein was performed by 3 different laboratory tests: Western-blot analysis, semi-quantitative reverse transcriptase-polymerase chain reaction analysis (RT-PCR) and finally immunohistochemical analysis. Cell cultures of tooth tissue examined are: endothelial cells, stellate reticulum cells, odontoblasts and ameoblast.

RESULTS

The VEGF peptide seems to induce an intense cell proliferation, not concomitant with differentiation towards the endothelial line. The expression of VEGF in the inner enamel epithelium (ameloblasts) would seem to depend on the stage of differentiation, leading us to deduce that VEGF and its respective receptor are expressed in dental germ and that induce alterations not only on the vascularization, but also on the inner epithelium activation and then on dental enamel development, respectively on cap and bell stages of embryogenesis.

CONCLUSIONS

In our survey, the positive expression of VEGF in all the samples examined, might suggest a fundamental role of angiogenic gene proteins during all stages of embryonic tooth development. It is also characteristic the behavior of stellate reticulum cells, with a significant reduction in VEGF action between early and late stage, which could suggest a possible role of stellate reticulum cells, which would be able to promote and maintain an adequate energy supply to the tissues during early and late stages of differentiation and proliferation.

Vascular endothelial growth factor and nitric oxide synthase expression in human tooth germ development

Vascular Endothelia Growth Factor (VEGF) and Nitric Oxide Synthase (NOS) expression, were evaluated in human tooth germs at two different stages of embryogenesis, to clarify the role of angiogenesis during tooth tissue differentiation and growth. Seventy-two third molar germ specimens were selected during oral surgery. Thirty-six were in the early stage and 36 in the later stage of tooth development. The samples were evaluated with Semi-quantitative Reverse Transcription-Polymerase chain Reaction analyses (RT-PcR), Western blot analysis (WB) and immunohistochemical analysis. Western blot and immunohistochemical analysis showed a VEGF and NOS 1-2-3 positive reaction in all samples analysed. VEGF high positive decrease reaction was observed in stellate reticulum cells, ameloblast and odontoblast clusters in early stage compared to later stage of tooth germ development. Comparable VEGF expression was observed in endothelial cells of early and advanced stage growth. NOS1 and NOS3 expressions showed a high increased value in stellate reticulum cells, and ameloblast and odontoblast clusters in advanced stage compared to early stage of development. The absence or only moderate positive reaction of NOS2 was detected in all the different tissues. Positive NOS2 expression showed in advanced stage of tissue development compared to early stage. The action of VEGF and NOS molecules are important mediators of angiogenesis during dental tissue development. VEGF high positive expression in stellate reticulum cells in the early stage of tooth development compared to the later stage and the other cell types, suggests a critical role of the stellate reticulum during dental embryo-morphogenesis.

The immediate functional loading of seven and mistral implants with new multi unit titanium abutments. 24 months follow up report

Immediate loading of dental implants has been defined as a situation where the superstructure is attached to the implants at time of the surgery or however no later than 72 hours after surgery. Micromovements have been deeply studied in dental implants loading but the question of reduction of micromovements has not been addressed in controlled studies dealing with immediate loading of oral implants. Passive fit of provisional prostheses has been mentioned as an important factor in the osseointegration of immediately loaded implants. The ultimate goal of an immediate loading protocol is to reduce the number of surgical interventions and shorten the time frame between surgery and prosthetic delivery, all without sacrificing implant success rates. Aim of this study was to evaluate the use of a new titanium abutments for screw retained prosthesis in edentulous patients in an immediate loading procedure in order to reduct the number of surgical steps.

Oral tuberculosis: a tongue case report

The authors report a case of oral tuberculosis in a 38-year-old heavy cigarette smoker man. He showed a painful, non-healing ulcer with indurated borders of the lateral surface of the tongue. No tonsil or lymph node enlargement was also noted. The medical history was not significant for systemic disease. Histopathological examination showed granulomas exhibiting a central caseinating necrotic focus, surrounded by mononuclear cells, epithelioid histiocytes and multi nucleated Langhans giant cells. A mantle of lympocytes and fibrous tissue surrounded the granulomas. Since the morphologic picture oriented for tubercoloid granulomata, a Ziehl-Neelsen staining of the tissue was performed. Chest radiography did not detect any pulmonary or nodal disease. On the bases of these results a diagnosis of oral tuberculosis was established.

Reconstruction of congenital isolated absent columella: a case report

Congenital isolated absent columella is a rare event in population, with an aetiology that is still unclear. Reconstruction remains a challenging problem. A single case is presented with the description of an original single stage surgical technique to restore it.

Effectiveness of chlorhexidine on dental plaque: a new technique

AIM

Regular home care by the patient in addition to professional removal of subgingival plaque is generally very effective in controlling most inflammatory periodontal diseases. The purpose of this study is to evaluate the effectiveness in removing plaque, a new tool for oral hygiene, suitable for any type of population, associating it to the patient's motivation in the early stages of a session of occupational hygiene.

METHODS

The experiment involved a total of 120 patients. In the initial stages of the professional oral hygiene treatment, there were the values for the percentage of plaque index in all 120 subjects, after application of the agent detector plate, containing erythrosin, in liquid solution. Subsequently, the same operator, used for about two minutes with a woven gauze roller movement toward apico-coronal (Digital Brush, Mycerium, SpA, Avegno, Ge) on all teeth. Soon after it was re-applied the same detector that has enabled us to evaluate the plaque index, after using the digital brush. A statistical analysis has been carried out.

RESULTS

Results show a statistically significant decrease of the averages of plaque index before and after treatment. At the end of the study the 120 patients showed an average index of plaque equal to 74.2, which after the use of the Digital Brush was reduced to 44.3.

CONCLUSION

The research has shown a very simple and effective treatment's procedure, therefore it should be widely employed in oral hygiene practice.

Oral manifestation of cleido cranial displasia

Cleidocranial dysplasia (CCD) is a congenital hereditary condition caused by a dominant autosomal mutation. The orthodontic management of CCD patients is often complicated by the manifestations associated with the condition. The aim of this study was to evaluate the oral manifestations of patients suffering from CCD. The subjects underwent a thorough clinical evaluation that examined both hard and soft tissue. The subjects also underwent an X-ray examination in order to isolate possible anomalies in the stomach region related to the condition. Case 1 presented with a bilateral cross-bite, retention of deciduous teeth, presence of supernumerary teeth and agenesis. Case 2 presented with bilateral cross-bite, retention of deciduous teeth, and the presence of supernumerary teeth. The individuals in this study represent a broad range of typical CCD manifestations and confirm the close correlation between the mutation at CBFA1 level and the presence or oral-dental alterations. An early diagnosis of CCD is essential and based on clinical manifestations, x-ray evidence and genetic tests. Diagnosing the condition can be difficult in cases where there are no evident morphological signs; however, in most cases, an alteration in the rhythm of deciduous tooth loss is immediately apparent, making a closer collaboration between dentists and geneticists fundamental in achieving early diagnosis. As stated above, the timing of the treatment is crucial in establishing a correct course of treatment that involves extractions, orthodontic surgery and the use of prosthetics.

Microarray evaluation of gene expression profiles in inflamed and healthy human dental pulp: the role of IL1beta and CD40 in pulp inflammation

Dental pulp undergoes a number of changes passing from healthy status to inflammation due to deep decay. These changes are regulated by several genes resulting differently expressed in inflamed and healthy dental pulp, and the knowledge of the processes underlying this differential expression is of great relevance in the identification of the pathogenesis of the disease. In this study, the gene expression profile of inflamed and healthy dental pulps were compared by microarray analysis, and data obtained were analyzed by Ingenuity Pathway Analysis (IPA) software. This analysis allows to focus on a variety of genes, typically expressed in inflamed tissues. The comparison analysis showed an increased expression of several genes in inflamed pulp, among which IL1β and CD40 resulted of particular interest. These results indicate that gene expression profile of human dental pulp in different physiological and pathological conditions may become an useful tool for improving our knowledge about processes regulating pulp inflammation.

Dentin sialophosphoprotein expression during human matrix development

Dentin sialophosphoprotein (DSPP) is a phosphorylated parent protein that is cleaved post-translationally into three dentin components: dentin sialoprotein, dentin glycoprotein, and dentin phosphoprotein. In this study we evaluated the dentin sialophosphoprotein expression in human tooth germs to determine its role in tooth development and matrix deposition. DSPP gene expression was investigated performing reverse-transcription polymerase chain-reaction (RT-PCR) and a microarray analysis carried out using high density array containing 21.329 transcripts in replicates. To test for the expression of the DSPP protein, were performed western immunoblot and immunohistochemical analysis during different phases of tissues and matrix formation. All the analysis performed showed high expression level of DSPP in human tooth germs indicating that it may play an essential role for physiological and pathological events in tooth development.

Factors affecting bone response around loaded titanium dental implants: A literature review

This paper was designed as a review of the knowledge concerning bone adaptation around dental implants. Current literature concerning the biomechanics of bone and titanium dental implants as a main focus and pertinent to key aspects of the review was taken into consideration. Implant stiffness, design and surface were considered as factors affecting bone response to loaded dental implants. The emerging data allows the conclusion that implant design influences force transmission to periimplant bone, but seems to have poor power in preventing time-related marginal bone crest resorption. Mechanical stimulation such as prosthetic stress-dependent strains, affects bone tissue adaptation. Therefore, it is crucial to have high biomechanical control on implants to preserve implant ankilosis and to promote periimplant bone deposition.

In vitro and in vivo follow-up of titanium transmucosal implants with a zirconia collar

The advantages of transmucosal healing implants with a bioactive zirconia collar as a support for partially fixed prosthodontic restorations are optimal peri-implant marginal tissue sealing, reduction in plaque accumulation and satisfactory aesthetic results. The zirconia used in this study evidenced not only optimal clinical performances, but also good biocompatibility. The results from this study demonstrated that zirconia coating enhances fibroblasts and osteoblast-like cell adhesion, spreading and proliferation, favoring microscopic tissue/cell in-growth and clinical implant fixation improvement. From clinical analysis, it emerged that the treatment group obtained better scores in every peri-implant parameter. This evidence attests faster stabilization of soft and hard tissues around both the transmucosal zirconia collar and at the crestal level of the implant. A reduced plaque accumulation around the implant with zirconia collar could provide a better peri-implant microbiological en-vironment by allowing the soft tissues expression of optimal sealing and good bone adaptation to loading. From these clinical and radiographic comparative analyzes, it emerged that in the treatment group the mean values were always similarly low. A rapid stabilization of both hard and soft peri-implant tissues was documented in the 1st yr. In the treatment group, there was the formation of stable tissue sealing the zirconia collar, which could preserve mucosal and bone levels. In conclusion, 2-yr clin-ical results demonstrated that implants supporting fixed restorations using transmucosal healing implants with a zirconia collar appeared a valid method, reporting 100% implant survival rates. Moreover, in vivo results obtained using strict parame-ters to assess the peri-implant status affirmed that a zirconia collar offers excellent biological acceptance. Our preliminary in vitro results statistically evidenced increased fibroblast and osteoblast adhesion and proliferation to zirconia compared to tita-nium, and an index of enhanced material integration with bone and soft tissue cells. (Journal of Applied Biomaterials & Biomechanics 2004; 2: 143-50).