Molar furcation entrance and its relation to the width of curette blades used in periodontal mechanical therapy

Abstract: Aim:  The purpose of this research was to evaluate molar furcation entrances and the width of periodontal curette blades used in periodontal instrumentation.
Materials and methods:  One hundred extracted molars (50 upper and 50 lower) were analysed. The furcation entrances were measured using orthodontic wires of different predetermined diameters: 0.4, 0.5, 0.6, 0.7, 0.8 and 0.9 mm. McCall 17–18, Gracey 5–6 and Gracey 5–6 mini-five curette blades were measured at their anterior (AT), middle (MT) and posterior (PT) thirds by a single trained investigator, through the use of a digital caliper.
Results:  The results showed significant differences ( P  < 0.0001) in relation to furcation entrances. The buccal upper molar furcations showed the narrowest dimensions. In relation to the blade diameter, significant differences among the instruments were found for their MT and PT ( P  < 0.0001), but not for the AT ( P  = 0.183). Significant differences were found among curette manufacturers. Nineteen per cent of evaluated furcations presented entrances <0.60 mm and 75% of the blades at their AT presented width >0.60 mm.
Conclusions:  These findings demonstrated that some molar furcation entrances could not be adequately instrumented with the tested curettes. The use of other hand instruments, such as periodontal files, rotating instruments and ultrasonic devices should be taken into consideration during periodontal therapy.