Tooth Fairy guilty of favouritism!

OBJECTIVES: To determine the proportion of children visited by the Tooth Fairy, the child-related factors that influence the likelihood of her visit, and the parent-related variables that affect the amount of money the Tooth Fairy leaves. DESIGN: Cross-sectional questionnaire study. SETTING: Zürich, Switzerland. PARTICIPANTS: 3617 parents of children (mean age of children, 6.8 years; 51.9% girls) who had lost at least one deciduous tooth received a self-developed questionnaire; 1274 questionnaires were returned (35.2%). MAIN OUTCOME MEASURES: Primary outcome variables were the Tooth Fairy's visit after tooth loss and the amount of money given in case of a visit. Child- and parent-related variables were assessed as predictors of the main outcomes. RESULTS: Most parents (71.0%) reported that the Tooth Fairy visited their child. She usually exchanged the lost tooth for money (55.8% of visits) or placed money next to the tooth (40.7%); rarely did she take the tooth without pecuniary substitution. The Tooth Fairy left an average of 7.20 Swiss francs (approximately AU$9.45). The Tooth Fairy favoured visiting for the teeth of older children (odds ratio [OR], per year, 1.87; 95% CI, 1.09-3.21), of boys (OR, 2.65; 95% CI, 1.09-6.42), and of children who believed in her (OR, 4.12; 95% CI, 1.77-9.64). The amount of money was influenced by maternal, but not paternal socio-demographic factors, including level of education (OR, per level, 0.78; 95% CI, 0.66-0.92) and country of origin (OR, Western countries v non-Western countries, 2.35; 95% CI, 1.20-4.62). CONCLUSIONS: The Tooth Fairy does not visit all children after tooth loss, displaying clear preferences in her choice of business partners. The odds of a visit are dramatically increased if she is believed in, and the value of a deciduous tooth is influenced by socio-demographic factors.

Surface and interfacial analysis of sandblasted and acid-etched enamel for bonding orthodontic adhesives.

INTRODUCTION: The purposes of this study were to characterize enamel surfaces treated with sandblasting, acid etching, or sandblasting followed by acid etching for bonding of orthodontic adhesives and to evaluate the enamel-adhesive interfaces. METHODS: Buccal premolar surfaces were sandblasted, acid etched, sandblasted and subsequently acid etched, or left intact. For 2 treatments (acid etching and sandblasting plus acid etching), orthodontic brackets were bonded for resin infiltration assessment. Surface roughness and enamel loss were evaluated by optical profilometry, and surface morphology and elemental composition were examined by low-vacuum scanning electron microscope/energy dispersive x-ray analysis, whereas interfacial resin infiltration was assessed by high-vacuum scanning electron microscopy. Differences were statistically analyzed by 1-way analysis of variance and Tukey-Kramer multiple comparison tests or t tests (α = 0.05). RESULTS: The sandblasted and sandblasted-plus-acid-etched groups showed higher surface roughness values than the acid-etched group. Sandblasting plus acid etching removed more enamel than did sandblasting or acid etching alone. Sandblasting plus acid etching demonstrated a more uniform type I etching pattern, without alumina particles implanted in the enamel, unlike sandblasting. No difference was found in the extent of resin infiltration between the bonded acid-etched and sandblasted-plus-acid-etched groups, although the latter showed improved infiltration characteristics. CONCLUSIONS: Sandblasting-plus-acid-etching treatment creates a rough enamel surface, typical of type I etching, with the greatest extent of enamel loss, free of alumina interferences, demonstrating the same extent of resin infiltration as acid etching, but exhibiting improved infiltration quality.