With respect to quality of root canal filling, tobacco use may not be a significant predictor for apical periodontitis.

The aim was to review the current evidence regarding an association between tobacco use, that is, cigarette smoking, and periapical pathosis. A systematic MEDLINE search of articles published prior to October 2011 (4th) was conducted using the keywords 'smoking and endodontics OR smoking and periapical index'. The study selection, data preparation and validity assessment were conducted by two reviewers. Nine studies fulfilled the inclusion criteria and represented data from 3008 individuals. The studies differed with respect to (i) study design, (ii) radiographic techniques, (iii) assessment of periapical pathosis, (iv) classification of smoking characteristics and/or (v) potential confounders accounted for in the analyses. Five of six cross-sectional studies revealed a significant positive association (OR 1.35-16.8) between periapical pathosis and current cigarette smoking. One of three longitudinal studies indicated an increased risk (OR 1.7) of root treated teeth for current smokers. The substantial heterogeneity of the included studies limited their interpretation. Further, well-designed studies are required to investigate the association between tobacco use and periapical pathosis.

Existence of appropriately done root canal fillings in periodontitis patients has no effect on the prognosis of periodontal disease.

Objective: To investigate the effects of size and taper of the apical preparation, root canal curvature and cannula diameter on the insertion depth of irrigation cannulas into root canals. Study Design: One hundred and four root canals were divided into four curvature groups (0-5°; 6°-15°; 16°-25°; >25°). After apical enlargement to size 25.06 a 25G and a 30G irrigation cannula were inserted until binding. The distance between the cannula tip and the working length was related to the root canal length. The insertion procedure was repeated after enlargement to 40.04. Results: In curved canals (>6°), the cannula never reached WL. With an apical preparation of 40.04 the 30G cannula could be introduced nearly to WL even in moderately curved canals (<26°). Conclusion: Only a 30G cannula allows delivery of the irrigant to the apex of a curved root canal. The cannula could be inserted closer to WL when the apical preparation size was wider with a smaller taper compared to a small apical preparation size with a wider taper.