Conventional Bite Rims or a Manchester rim ?
Although Manchester rims and conventional bite rims look similar and may give you the same result, it actually simplifies the process of taking a bite registration effortlessly due to its design.
Manchester rims have a few advantages over CBRs:
- After a certain amount of time wax can change dimensionally and make the bite rim loose and may not allow you to asses retention, extension, stability and support.
- A solid base plate allows you to asses the retention and stability of the base plate and establishes a relationship between the base and the underlying tissues. You can easily take an imp wash inside the base plate if it is not sufficient.
- It allows you to check the extensions around the peripheral area and trim that area if there is interference or cheek dislodgement. (see our Taking denture impression like a pro guide to see how this is important).
- Being stable & retentive allows you to seat the MRs without having to worry about it dropping whilst preforming a bite registration. This also makes life easier when assessing the frontal and occlusal plane with a fox gauge.
- It allows you easily capture the patients facial features with the rims being retentive and stable, e.g the centre line will not move as the base plate will keep the rim stationary.
- The lower rim is made with blocks between the premolar to the molar region and is only used to obtain and lock the OVD which provides accurate control over the OVD. When the contacts, bilaterally, are even at the selected OVD it can be locked together via a PVS or putty material, which allows you to simply place it back into the mouth to verify its accuracy.
- Its patient friendly, if made correctly, it does not feel like a mouthful of wax.
- The drawback is the uncertainty of achieving the most retruded mandibular position and the lack of information on eccentric mandibular movement (if this is what you need, you may prefer to use Gothic arch tracing method instead).