Two common vehicles used with calcium hydroxide Ca(OH)₂ are normal saline and camphorated parachlorophenol (CMCP). The use of propylene glycol as a vehicles was reported by Laws in 1962, but has not gained favour among endodontists. This in-vitro study was undertaken to evaluate the effect of mixing vehicles on the pH of calcium hydroxide pastes prepared in propylene glycol, camphorated parachlorophenol and normal saline. It was found that a paste of Ca(OH)₂ and propylene glycol produced a consistently higher pH over a period of 2 weeks than a paste of Ca(OH)₂ and normal saline solution. A Ca(OH)₂- propylene glycol paste produced a mean pH of 10.92 at 24 hours which is higher than the pH produced by the other two pastes at any time. 10.2 is the optimal pH for the activity of alkaline phosphatase responsible for reparative activity at the apex. Hence this paste may be a better vehicle for clacium hydroxide.

Two hundred extracted, human, permanent, mandibular second molars were studies by utilizing the ratio-opaque dye ‘Conray-280’, as a contrast media for the radiographic analysis. Maximum variations were seen in the mesial root canals. The lateral canals were found in the mesial of the distal root and they were llocated at the middle third of the roo in about 5.5.% of the cases. 78.5% of the teeth showed completely seperated mesial and distal roots and about 21.5% showed fused or cone shaped roots. 61 teeth (30.5%) showed single canal (Type-I) Of the remaining, 136 teeth exhibited two mesial canals - Type-II in 84% and TypeIII in 16%. Two teeth has a single middle canal and one had a ‘C’ shaped canal.

Morphologically the mandibular molars present three root canals. One distal and two mesial having either Type-I or Type-II canal configuration (78 %). An interesting case of bilateral mandibular second molars having three seperate roots and four canals is illustrated along with its successful management in this report.