Part II Practical Test - phantom-head technique and material handling
Part II is the bench test: you perform pre-clinical procedures on mounted typodont teeth - and sometimes extracted teeth - under observation and against a time limit. It exists because a written paper cannot show whether your hands can produce a preparation a laboratory or a patient can actually live with. It is the middle hurdle, taken after Part I.
Typical scope
- Operative preparations: Class II (amalgam or composite), Class III/IV and occlusal cavities, judged on outline form, resistance and retention form, smoothness of walls and floor, and preservation of remaining tooth structure.
- Crown preparations: full-coverage metal and/or ceramic, judged on axial and occlusal reduction, taper, finish-line design and absence of undercuts.
- Endodontic access and canal preparation, and, depending on the current syllabus, tooth morphology wax-ups or appliance wire bending.
Technique rules
- Plan before you cut: probe the tooth, note the bur's diameter, and cut a reference groove to the target depth before extending laterally.
- Reduce with a water-cooled high-speed handpiece; finish with fine grits under magnification and good light.
- Standard targets: axial reduction about 1.0–1.5 mm; occlusal reduction about 1.5 mm for metal and up to 2 mm for ceramic; total taper of roughly 6–10°; chamfer for metal, rounded shoulder for ceramic.
- Protect adjacent teeth and the typodont soft tissue - iatrogenic damage is highly visible and heavily penalised.
Worked example
A mesio-occlusal composite cavity in a mandibular first molar. Reasoning: confirm the contact with the second molar on the model; enter occlusally with a small fissure bur; extend to the mesial marginal ridge; drop the proximal box with the bur held parallel to the long axis so the gingival seat clears the contact point; break the contact from inside so the adjacent tooth is not nicked; keep the isthmus near one-third of the intercuspal distance; smooth the walls, then inspect with a probe and mirror before calling the examiner. Each step is checked against a measurable target rather than by eye.
Traps that cost marks
- Judging depth by eye instead of using a measured reference groove.
- Under-reducing (bulky crown, poor retention) or over-reducing (pulpal exposure).
- Nicks on adjacent teeth.
- Chasing a perfect finish line and running out of time - an unfinished cavity scores nothing.
- Poor instrument organisation or lapses in bench asepsis.