Technique tips

The Manchester bite block is a modified lower occlusal rim that was first described by McCord and Grant in 2000.¹ The Manchester bite block (Figure 1) has two pillars of wax situated bilaterally in the region of the mandibular second premolar-first molar tooth positions. It provides the clinician with a simplified lower rim to record the jaw registration stage of complete denture construction.

The aim of this paper is to revisit the Manchester bite block jaw registration technique and to introduce clinicians to a further modification that can be made to outline the position of the lower anterior teeth to the technician.

A jaw registration record can be made by the mandible closing in its retruded arc of closure with occlusal rims separating the maxilla and mandible at the selected occlusal vertical dimension (OVD).¹

The use of conventional upper and lower wax rims (Figure 2) is one of the most common jaw registration techniques. In this technique, the lower wax rim is placed in the mouth and trimmed until it contacts the upper rim evenly in the retruded contact position (RCP) at the selected OVD. This is done by selectively removing points of first contact bilaterally. It can be difficult to detect these premature contacts and accurately remove them along the entire length of the rims bilaterally.¹ Furthermore, prior to securing a jaw registration, the lower wax rim should be adjusted in bucco-lingual width until within the ‘neutral zone space’.² This is important to provide tongue space, facial tissue support and lower complete denture stability.^3,4 One of the disadvantages of this technique is that it can be difficult to identify this space accurately and adjusting the wax bucco-lingually can be a time consuming process to carry out.