Maternal Smoking during Pregnancy Is Associated with Offspring Hypodontia

Little is known about environmental risk factors for hypodontia. The objective of this study was to investigate the association between hypodontia and common environmental risk factors, such as maternal smoking and alcohol and caffeine consumption during pregnancy. Eighty-nine hypodontia cases with 1 or more missing permanent lateral incisors and/or 1 or more missing premolars were enrolled in this clinic-based case-control study. Some 253 controls with no missing teeth were frequency matched to cases by age and sex. Hypodontia was diagnosed using panoramic radiographs. Sociodemographic data were collected from both the participants and their mothers, with maternal self-reported active and passive smoking, as well as alcohol and caffeine consumption during pregnancy, assessed by a questionnaire. Odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated with logistic regression to assess the strength of association between risk factors and hypodontia. OR estimates were then adjusted for possible confounders, such as maternal age at delivery, sex and gestational age of the child, and household socioeconomic background. Significant associations were found between hypodontia and maternal cigarette use during pregnancy, as well as the number of cigarettes smoked per day. The consumption of 10 or more cigarettes per day during pregnancy was associated with greater odds of having a child with hypodontia (adjusted OR, 4.18; 95% CI, 1.48-11.80; P = 0.007). Observed associations between hypodontia, second-hand smoke, and alcohol and caffeine consumption were not statistically significant. Maternal smoking during pregnancy is associated with hypodontia. Larger samples and prospective observational study designs, however, are needed to investigate this association further.

Hypodontia: An Update on Its Etiology, Classification, and Clinical Management

Hypodontia, or tooth agenesis, is the most prevalent craniofacial malformation in humans. It may occur as part of a recognised genetic syndrome or as a nonsyndromic isolated trait. Excluding third molars, the reported prevalence of hypodontia ranges from 1.6 to 6.9%, depending on the population studied. Most affected individuals lack only one or two teeth, with permanent second premolars and upper lateral incisors the most likely to be missing. Both environmental and genetic factors are involved in the aetiology of hypodontia, with the latter playing a more significant role. Hypodontia individuals often present a significant clinical challenge for orthodontists because, in a number of cases, the treatment time is prolonged and the treatment outcome may be compromised. Hence, the identification of genetic and environmental factors may be particularly useful in the early prediction of this condition and the development of prevention strategies and novel treatments in the future.

Noise levels in dental school clinics

Prolonged exposure to noise is a little-investigated occupational hazard in dentistry. There is anecdotal evidence suggesting that noise levels in four student clinics at the School of Dentistry are higher than the current occupational noise level guidelines in New Zealand, Australia and the United Kingdom, which suggest that levels should not exceed 85 dB (A) over a duration of 8 hours. The objectives of this study were to (1) measure the noise levels in the student clinics, and (2) determine whether they exceed current guidelines for occupational noise levels.

METHOD

A noise level meter was used to measure the decibel recordings in dB (A), before and during clinical sessions. The types of procedures being carried out by the students were recorded.

RESULTS

127 background recordings and 126 activity recordings were made, with measured noise levels ranging from 50.2 to 77.6 dB (A) for background levels, and 51.4 to 98.0 dB (A) during activity, with means of 60.8 and 70.5 dB (A) respectively. Measurements made in one clinic (the 4SW clinic) were significantly higher than those made in the other clinics (P < 0.001), and one (clinic 2N) gave the lowest readings.

CONCLUSION

Noise levels recorded from the clinics at the Otago School of Dentistry exceed those specified in the current New Zealand Occupational Health and Safety guidelines, but they are intermittent rather than continuous.