One of St. Lawrence Dentistry’s key focus areas is jaw bone preservation and its rebuilding.
Bone can be lost in the mouth for a variety of reasons. The two biggest are bone loss as a consequence of a tooth removal and gum disease (periodontal disease). The most important items in Dr. Hawryluk’s bone building armamentarium are ‘collagen membranes’ and ‘bone grafting materials’. The article focuses on membranes in particular. The membranes that Dr. Hawryluk uses stabilize the position of bone added to the jaw to build it up.
The 3 types of barriers used at St. Lawrence Dentistry to protect newly added bone are ‘dressings’, ‘processed collagen membranes’, and ‘processed tissue membranes’.
Collagen is the main structural protein found in skin and other connective tissue. Collagen fibers support gum tissues, plus collagen is a major component of the matrix that supports cells. Collagen and keratin give the gum its strength, waterproofing, and elasticity.
Collagen Membranes are ‘type 1 collagen’ of bovine (cow) origin which is made into a sheet which can cover over a bone graft and give it a shape and a structure. Type I collagen is the most abundant and is found in scar tissue, skin, tendons, artery walls, and bones. It is a very strong type of collagen, with good tensile strength. Type 1 collagen is really the molecule of choice for most of our membranes. It is the most abundant protein in the body, has a triple helix, and there is excellent biocompatibility between species. This means we can use products which are bovine or pig based and use them for human grafting procedures. Since it is the most abundant protein in the body, out body has good mechanisms for resorbing it.
Tissue membranes are either made of pig, cow, or human tissues which have been processed in a way to take away cells which leaves only a collagen matrix behind. An example of this type is the Bio-Guide membrane which Dr. Hawryluk uses for the Pinhole Gum Rejuvenation procedure.
Dressings are collagen products used to stabilize early wounds. These are used for simple bone grafting when all the size bone of a tooth socket is intact. In this instance the dressing functions as a wound stabilizer rather than a barrier. These are also a type 1 collagen product. Dr. Hawryluk uses BioHorizons products called ‘BioStrip’ and ‘BioPlug’ which are collagen wound dressings designed to absorb blood or fluids and protect the dental site for optimal regeneration.
In instances where the side bone of a tooth socket is missing (fenestration) Dr. Hawryluk uses a collagen membrane as it will reestablish the boarders of where the ‘alveolar’ bone will be regenerated too. They are longer lasting than simple collagen dressings and prevent the gum tissues from migrating inwards to where we want bone to form. Dr. Hawryluk uses a membrane called ‘Mem-Lok’ which is produced by Biohorizons. It is engineered from highly purified type I collagen to provide an increased resorption period and ensure optimal bone regeneration.
In a simple socket preservation procedure, Dr. Hawryluk will take the tooth out as gently as possible and then examine the socket to make sure there are no breaks in the bone plate. He will then place particulate bone into the socket. If there are no breaks he will create a lid with the BioHorizons BioPlug effectively sealing up the socket and bone. The plug is sutured and then will stay there for about 5-10 days and is resorbed over time through the enzymes in the saliva and blood. After 4 months time, we will see a nice healed up socket with new bone which as grown underneath. If implants are planned you will now be able to get them placed in the newly regenerated socket bone graft.
A collagen membrane is used instead of a wound dressing for three main reasons:
- If the bone around a tooth socket is damaged or extremely thin
- When a bone graft is placed outside the socket bone (instead of inside)
- When a long lasting barrier function is needed
Collagen dressings like BioPlug are very useful but do not last long enough to do any of these 3 things.
Choosing the membrane with the right resorption time is critical. Dressings like Bio-Plug last 2 weeks or less. Bio Horizons Mem-Lok will stay for 6-10 weeks. It is very strong and acts as a barrier during the critical bone formation period. Bio-Guide is a tissue processed membrane which lasts around the same time frame. It is also used at St. Lawrence Dentistry and is made from Porcine.
A collagen membrane does 3 things.
- Support the hard (bone) and soft tissue (gum) healing
- Support and stabilizes the bone graft
- Excludes fast growing epithelial cells (outer gum cells) from slow growing bone
For many years we thought point 3 (prevention of epithelial cells from accessing the bone) was the most membrane function. However, it is not quite that way. You can actually poke holes in a membrane and you will still get plenty of bone growth and sometimes even enhanced bone growth. The newer generation of membranes used at St. Lawrence Dentistry actually let nutrients and metabolites pass through the membrane which enhances the bone growth.
Choosing the right membrane with respect to its handling properties is very important. Some membranes are soft and can drape over and area while others are harder and have memory.
A Bio Guide membrane is very soft and will adapt in shape to the area underneath the membrane. Whereas the Mem-Lok membrane is rigid and wants to maintain its shape like an umbrella. If a patient has a bone defect from a traumatic extraction and we need to fill it, Dr. Hawryluk will often use a more rigid membrane which gives a ‘tenting effect’. Hence when he fills the defect with bone it can hold its own shape. After a healing time of several months, an implant can then be placed.
The periosteum (bone tissue lining) acts as a natural barrier but it does not hold the shape for several weeks as a membrane does. The periosteum tends to conform to the shape of the wound underneath and this will undermine the bone growth. There is no epithelium (tissue which migrates inwards disrupting bone) on the inside of the flap where the periosteum is. However, sometimes the periosteum needs to be slit to introduce flexibility in the flap and this can introduce it. Also granulation (healing tissue) tissue can cause epithelium infiltration.
Dr. Hawryluk will do everything possible to get excellent results to your any jaw bone augmentation. This will facilitate possible placement of dental implants and preserve your natural facial features.
If you are looking for a new dentist in Mississauga or would like to discuss this topic please call us to make a time to visit St. Lawrence Dentistry.