What is a Maryland Bridge?
A Maryland bridge consists of a porcelain tooth, known as a Pontic and a metal wing which is used to replace spacing at the anterior of the mouth. The Pontic is made of porcelain bonded onto a metal backing for strength and will have one or two wings which will be cemented onto the enamel of the next natural tooth.
Maryland bridges are a good replacement for a tooth that has maybe been knocked out in an accident. They are also used to close any noticeable gaps which for some people can cause a crisis in confidence. The can also replace a space due to a tooth having to be extracted for any reason. With an extraction the dentist frequently makes an immediate partial denture to cover the space for the patient which is fitted on the day of extraction so the patient does not have to have a gap while the gum is healing before the dentist can begin the preparation. This can be around 12 weeks.
The advantages of a Maryland Bridge is that there is not very much disturbance to the tooth in which the wing will be attached to as only a small adjustment may be needed to be carried out. This will help conserve the natural tooth enamel and the dentine will not be exposed. They are good for smaller spaces in the mouth and will take less time in the chair to prep than a cantilever bridge which generally means they are quick to fit as well, which is good for nervous patients. Also you generally don’t need an anaesthetic as it is such a small adjustment although those with sensitive teeth may prefer an anaesthetic.
The disadvantages of this type of bridge are that it is only suitable for certain sizes of spacing – small spaces at the front of the mouth. Also, if the bridge did come loose, the bridge needs to be sent back to the technician to be reconditioned so it is not as straight forward as cementing it back in again and may leave the patient with a gap for a couple of days while the technician has it.
The Procedure
Generally, the patient won’t need an anaesthetic, unless they are sensitive, or some people just prefer having it done as to not feel anything. The dentist will begin by taking an alginate impression of the opposite teeth – if the Maryland is going on the lower jaw, the alginate will be taken of the upper jaw or vice versa. This will be taken in the appropriate sized impression tray and will have adhesive spread onto it to hold the alginate in place. The nurse will measure out the correct amount of alginate to correlate with the size of tray. The nurse will then mix the correct measure of water to the alginate powder to form a thick paste. The dentist will then load this into the tray and place into the patients’ mouth for approximately 2 minutes. They will then take a bite registration. This is done by spreading a bite registration mix across the patients’ Occlusal biting surface and the patient will be asked to bite down with their normal bite. This sets in approximately 1 minute. The dentist does theses two impressions to help the dental technicians cast up the upper and lower jaws and record the bite to match the restoration to the mouth.
The dentist will then begin to prepare the tooth for the wing of the Maryland. Some Maryland’s have one wing, others have two, and the dentist will decide how many due to the amount of retention they evaluate is needed. The dentist will make a small indentation into either the Palatal or Lingual surface of the tooth, again depending on upper or lower using a fast hand piece and appropriate bur. You will be required to aspirate during this. Once happy with the preparation, the dentist will then ask for a putty impression. The putty is usually a base and catalyst mix of material (Aquasil, for example). This is to be mixed by hand until it has become fully blended together. (A few dentists out there have a machine that mixes it for you, you literally just hold the tray below it to load it up, but you will more than likely mix by hand) This will be loaded into another impression tray. The dentist will then place this into the patients’ mouth in an impression tray and leave to set for approximately 3 minutes. The dentist will then remove this impression and will then place a light body mixture over the impression, and on the site of the prepared tooth and places back into the mouth again for a few minutes again. This light body material gives a more accurate reading of the prepared tooth. Once these impressions have been taken, sometimes the dentist will place a small temporary filling material such as Coltosol onto the small preparation space to reduce sensitivity and protect the area.
Most times with Maryland’s, the patient has had an anterior tooth removed a few weeks beforehand and therefore generally has had a small partial denture to cover the space. The patient will wear this denture for another 2 weeks while the bridge is being constructed by the technicians. Some people who have had a gap for a significant amount of time are usually happy to continue with this gap until the fit appointment as temporary bridges of this nature are quite awkward to make and are not the most retentive. All impressions will be set into a disinfection bath such as Gigasept for 10 minutes to kill all germs and infection. The alginate impressions will need to be wet wrapped – this is best done by wetting the tissue first then wrapping the impression. The putty impression and bite does not need to be wet wrapped as it is unlike alginate which can warp if not kept damp. Alginate can also warp the other way; by being submerged in water for too long so don’t keep it in the bath for longer than 10 minutes. The Lab docket will contain information such as Dentists name, patients name, type of work, shade and whether it is NHS or Private.
The Laboratory will have the impressions for 2 weeks to prepare the bridge. On the day of the fit the dentist will remove the temporary filling with a fast hand piece and will place the bridge in place to check shade, fit and bite. Once the patient and dentist are both happy with the bridge, the nurse will mix a luting cement such as Fuji Plus. This is generally in a translucent shade. The mix must be luting – powder and liquid fully mixed together and once scooped up onto the spatula should have almost like a very slow dripping consistency to it. The dentist will dry the tooth and then place the cement onto the wing and will set in place until set all the while removing any access cement that may be over pouring from the area. Once set, the dentist will check the bite again with articulating paper and if an adjustment is needed the dentist will alter the Maryland slightly with a fast hand piece and appropriate bur.
Once happy with the fit and bite, the dentist will give Oral Hygiene Instruction (OHI) to the patient about the care of their Maryland. Many patients don’t realise that you need to take as good care of bridges and crowns as they do their natural teeth. The dentist will explain about flossing around the area and using Super Floss around the bridge itself. The need to keep the area healthy will be reiterated due to the tooth being the supporting tooth of the bridge and any damage, neglect or decay to the supporting tooth will compromise the Maryland.
What do I need?
In surgery you will need the following:
- Mirror
- Probe
- Tweezers
- Spoon Excavator
- Ball Ended Burnisher
- Flat Plastic
- Wards Carver
- Hand Pieces – Slow and Fast
- Appropriate burs
- Saliva ejector
- Aspiration tip
For the preparation you will need:
- Appropriately sized impression trays – upper and lower
- Tray adhesive
- Alginate – Bowls and spatula
- Bite registration
- Putty – base and catalyst
- Mixing tips
- Articulating paper
- Temporary filling material
- Floss
- Microbrushes
- Wet tissue
- Bags
- Lab docket
