Implant overdenture maxillo-mandibular relations
- Accurate recording of patient’s maxillo-mandibular relationships provide essential clinical documentation to establish correct occlusion, function and esthetics
- Occlusion rims are contoured to determine the height of the occlusal plane, vertical dimension of occlusion (VDO), lip and smile lines and circum-oral support
- Articulated casts offer an easy and reliable analogue for laboratory simulation of jaw movements
Maxillo-mandibular relations – interocclusal records
Accurate and repeatable recording of patient’s maxillo-mandibular relationships are essential for all types of oral rehabilitation. They provide essential clinical documentation that enables dentists and technicians to create the occlusal relationships necessary to meet the patient's functional and esthetic needs. When masticatory health and natural or correctly restored dentitions are present, inter-occlusal records are routine clinical steps. Many different materials are available to make such records and transfer them to an articulator.
Use of implants to stabilize record bases
Management of edentulous patients often requires additional clinical skill and patience to accurately obtain this record, since the inherent instability of occlusion rims - analogues for the missing dentition - may preclude its accuracy. This challenge is virtually negated when implants are present, irrespective of whether the treatment objective is a fixed prosthesis or an overdenture one.
Consequently, presence of 2 or more implants provides stability for the overlying record bases that support the wax occlusion rims. The bases may also include specifically designed mechanical components - female housings that fit over male ball anchors placed on the implants – with a cross-arch location, that ensures the rims’ accurate location and stability.
Fabrication of wax occlusion rim(s) and articulated casts
The technique with wax rims fabricated on the master casts is still considered the gold standard to determine maxillo-mandibular relations and interocclusal registration in edentulous patients. The wax rims establish the vertical dimension and delineate the occlusal plane, the lip line, smile line and midline.
Numerous techniques (from a simple ‘check bite’ record to more elaborate Gothic arch tracings) have been proposed to complete the centric relation record prior to its transfer to an articulator. Careful guidance of the patient's mandible during jaw closure facilitates the interocclusal registration process to record centric relation. The clinician must be careful to ensure that the record bases are positioned properly and fully seated and they do not move while the interocclusal registration material is setting. The ideal registration material is quick-setting, is free-flowing to offer little resistance during closure, and sets rigidly. Recording of maxillo-mandibular relations may be done with or without the use of a facebow. Articulated casts offer an easy and reliable analogue for laboratory simulation of jaw movements.