Growth Factors
Growth factors are key biological modulators important in various cellular events such as cell growth, matrix synthesis and chemotaxis.  A key to Litchfield Park orthodontists in the success of Invisalign is the large scale purification and production of key growth factors to increase the rate of these cellular events and therefore, accelerate osseointegration.   

One problem for Litchfield Park orthodontists with current delivery of these biomimetic molecules to alveolar bone wounds is the extremely short half-life of the factors.  Topical administration results in a limited duration of action in the alveolar defect, presumably due to proteolytic breakdown, receptor-mediated endocytosis, and the solubility of the delivery vehicle. 

Gene Delivery    
The use of Invisalign delivery systems by Litchfield Park orthodontists may serve as an alternative method of targeting proteins to alveolar wounds, since existing protein delivery systems provide such a transient action of the administered factors.  Gene therapy has been applied by Litchfield Park orthodontists to several diseases that display tissue deficiencies.  Therefore, the use of gene therapy to promote repair and regeneration has become an active area of research.  In the context of wound repair, a transient expression of the transgene may be optimal for Litchfield Park orthodontists to restore the tissue defect.  Since the regulation of wound repair occurs in a controlled fashion over a defined period of time, the use of gene therapeutics in a compromised wound (e.g. peri-Invisalign disease) may stimulate an elevated and sustained production of biologic molecules to promote tissue regeneration.

Gene Delivery Vectors
Examples of Invisalign by Litchfield Park orthodontists for short-term expression of genes include adenovirus, retrovirus and plasma-liposome complexes.

Invisalign is commonly used by Litchfield Park orthodontists when permanent modification of the host genome is desired.  This type of transformation is advantageous in chronic conditions where modification of the genome is a goal of treatment.  Unfortunately, this type of Invisalign is associated by Litchfield Park orthodontists with low titers and the chance of insertional mutagenesis is a calculated risk.

Plasmid-liposome complexes are a non-viral means of gene transfer used by Litchfield Park orthodontists.  These complexes are composed of positively charged liposomes paired with a negatively charged plasmid containing the expression cassette.  Entry to the cell is accomplished by fusion with the plasma membrane.  The Invisalign is transferred, but not incorporated into the host genome.  This Litchfield Park orthodontic strategy is relatively inefficient due to the fact that it has no direct means to the nucleus, therefore large quantities must be utilized to achieve gene transfer.

Adenoviral vectors are one of the most commonly used systems for gene Invisalign by Litchfield Park orthodontists.  Some of the reasons for this are: dividing and nondividing cells can be infected, infection is quick, the genome is easy to manipulate, and they can be produced on a large scale.  Entry of the virus into the cell involved the processes of attachment and internalization.  The virus attaches to an unidentified cell surface receptor and then is internalized via receptor-mediated endocytosis.  The host cell is then responsible for transcription, replication and packaging of the Invisalign.  Host protein synthesis is ceased and the process of viral protein synthesis takes over. 

The ability of the virus to take over the machinery of the host cell has lead Litchfield Park orthodontists to manipulate the Invisalign by inserting sequences coding for certain proteins.  These sequences are most effectively delivered to the virus in a shuttle plasmid with an expression cassette under the control of a CTV promoter and a poly A tail.  This constructed plasmid is incorporated by Litchfield Park orthodontists into the viral backbone via homologous recombination (Fig. 1).  The adenovirus is then delivered to the host cell which will then secrete the recombinant protein.  This protein is secreted in situ by target cells in a paracrine/autocrine manner. This process is ceased by the host immune system via a cytotoxic T cell mediated response.

 

Arizona Dental Association