ObjectiveTo compare the periodontal bone height (PBH) of exclusive narghile smokers (ENS) with that of exclusive cigarette smokers (ECS).MethodsTunisian males aged 20–35 years who have been ENS for more than five narghile-years or ECS for more than five pack-years were recruited to participate in this comparative cross-sectional study. Information about oral health habits and tobacco consumption were gathered using a predetermined questionnaire. Plaque levels were recorded in four sites using the plaque index of Loe and Silness. The PBH was measured mesially and distally from digital panoramic radiographs of each tooth and expressed as a percentage of the root length. A PBH level ≤0.70 was applied as a cutoff reference value signifying bone loss. Student t-test and Chi2 test were used to compare quantitative and qualitative data of both groups.ResultsThere were no significant differences between the ENS (n=60) and ECS (n=60) groups regarding age and the consumed quantities of tobacco (28±4 vs. 27±5 years, 7±3 narghile-years vs. 8±3 pack-years, respectively). Compared with the ECS group, the ENS group had a significantly higher plaque index (mean±SD values were 1.54±0.70 vs. 1.84±0.73, respectively). However, the two groups had similar means of PBH (0.85±0.03 vs. 0.86±0.04) and tooth brushing frequencies (1.1±0.8 vs. 0.9±0.6 a day, respectively) and had similar bone loss frequencies (15% vs. 12%, respectively).ConclusionsBoth ENS and ECS exhibited the same PBH reduction, which means that both types of tobacco smoking are associated with periodontal bone loss.

The aim of the present comparative study was to compare some salivary characteristics between exclusive waterpipe smokers (EWPS) and non-smokers. 72 males (36 EWPS) were recruited. The volume of stimulated saliva was determined and divided by the duration of saliva collection. The pH was measured directly using a pH meter. The buffering capacity was determined using a quantitative method which involved the addition of 10 µl HCl. Up to a total of 160 µL was titrated up to obtain a pH titration curve. At 50 µL of titrated HCl, buffering capacity was ranked into three categories: high, medium and low. EWPS and non-smoker groups had similar flow rates (1.81 ± 0.79 and 1.78 ± 1.14 mL min-1) and similar baseline pH (6.60 ± 0.37 and 6.76 ± 0.39). Statistically significant differences in the two groups’ pH were observed from 30 to 160 µL of titrated up HCl. At 50 µL of titrated up HCl, the EWPS group compared to the non-smoker group had a significantly higher pH (4.79 ± 0.72 vs. 5.32 ± 0.79). To conclude, waterpipe tobacco smoking alters the buffering capacity but does not alter either salivary flow rates or the baseline pH and consistency.

Studies evaluating the effects of narghile use on the periodontium present conflicting conclusions. This study aimed to compare the periodontal status of exclusive narghile smokers (ENSs, n = 74) to that of exclusive cigarette smokers (ECSs, n = 74). Males aged 20–40 years were recruited to participate in this comparative study. Information concerning oral health habits (number of yearly visits to the dentist, daily toothbrushing frequency) and tobacco exposure were obtained. Clinical measurements were performed on all the existing teeth, except the third molars. The number of remaining teeth and decayed/missing/filled teeth (DMFT) were noted. The plaque levels were recorded using the plaque index of Löe and Silness. The gingival index modified by Löe was used to evaluate gingival inflammation. Teeth mobility was measured using bidigital mobility. The probing pocket depth was measured using a periodontal probe. Periodontal disease was defined as the presence of at least 10 sites with a probing depth ≥5 mm. Student’s t and chi-square tests were used to compare, respectively, the two groups’ quantitative and qualitative data. The two groups were matched for quantities of used tobacco, age, daily toothbrushing frequency, teeth mobility, number of remaining teeth, plaque index, and DMFT. Compared to the ECS group, the ENS group had a significantly lower number of yearly visits to the dentist (mean ± SD : 0.2 ± 0.5 vs. 0.1 ± 0.2), lower probing pocket depth (mean ± SD : 2.33 ± 0.63 vs. 2.02 ± 0.80 mm), and gingival index (median [interquartile]: 0.46 [0.10–0.89] vs. 0.00 [0.00–0.50]), and it included significantly lower percentages of smokers with periodontal disease (24.3% vs. 9.5%). In conclusion, chronic exclusive narghile smoking has fewer adverse effects on the periodontium than chronic exclusive cigarette smoking.

This paper describes a novel method for a non-linear camera calibration. This method is based on genetic algorithms. Our motivation is to improve the accuracy of the calibration process. In our approach, the camera calibration is considered as an optimisation problem that can he solved by the genetic algorithms. We show that the proposed technique can correctly find the near-optimal solution without the need of initial guesses. Results from our study are compared with another method based on the non-linear minimization with the Newton-Raphson algorithm.