ABSTRACT
INTRODUCTION: The primary aim of this study was to better understand how bone adapts to forces applied to miniscrew implants. A secondary aim was to determine whether the direction of force applied to miniscrew implants has an effect on bone surrounding the miniscrew implants. METHODS: A randomized split-mouth design, applied to 6 skeletally mature male foxhound dogs, was used to compare miniscrew implants loaded for 9 weeks with 200 or 600 g to unloaded control miniscrew implants. By using microcomputed tomography, with an isotropic resolution of 6 µm, bone volume fractions (bone volume/total volume) were calculated for bone around the entire miniscrew implant surface. Bone volume fractions were calculated for bone 6 to 24, 24 to 42, and 42 to 60 µm from the miniscrew implant surface. For each loaded miniscrew implant, the bone volume fraction was also calculated for 2 compression and 2 noncompression zones. RESULTS: The 6 to 24-µm layer showed a significantly lower (P <0.05) bone volume fraction than did the 24 to 42-µm and the 42 to 60-µm layers, which were not significantly different. The bone volume fractions of cortical bone surrounding the apical aspects of the unloaded miniscrew implants were significantly greater (P <0.05) than the bone volume fractions of cortical bone surrounding the loaded miniscrew implants. In contrast, the bone volume fractions of noncortical bone surrounding loaded miniscrew implants were significantly greater (P <0.05) than the bone volume fractions of bone surrounding the unloaded miniscrew implants. Miniscrew implants loaded with 200 g showed significantly greater (P <0.05) amounts of noncortical bone volume fractions than did miniscrew implants loaded with 600 g. With both 200 and 600 g, zones under compression had significantly greater bone volume fractions than did the noncompression zones. CONCLUSIONS: The application of force, the amount of force applied, and the direction of force all have significant effects on the amounts of bone produced around miniscrew implants.
Subject(s)
Alveolar Process/pathology , Bone Screws , Dental Implants , Imaging, Three-Dimensional/methods , Mandible/pathology , Orthodontic Anchorage Procedures/instrumentation , X-Ray Microtomography/methods , Alveolar Process/diagnostic imaging , Animals , Bone Density/physiology , Dental Alloys/chemistry , Dogs , Image Processing, Computer-Assisted/methods , Male , Mandible/diagnostic imaging , Nickel/chemistry , Orthodontic Appliance Design , Orthodontic Wires , Random Allocation , Stainless Steel/chemistry , Stress, Mechanical , Surface Properties , Time Factors , Titanium/chemistryABSTRACT
PURPOSE: The purpose of this study was to analyze American Association of Poison Control Centers (AAPCC) reports of suspected overingestion of mouthwash by children under age 6 and examine the effect of a 1995 Consumer Product Safety Commission (CPSC) rule requiring child-resistant packaging for mouthwashes containing at least 3 g (0.11 oz) of ethanol per package. METHODS: The volume of ethanol ingested per kg of body weight was computed for children at the 5th, 50th, and 95th percentiles. The potentially toxic and potentially lethal volumes of 100% ethanol at each weight were also determined. The authors used segmented regression to test the difference in slopes between 1989 to 1996 (preintervention) and 1996 to 2003 (postintervention). RESULTS: Incidence of overingestion rose from a low of 12.7 per 100,000 (1991) to 20.7 (1996). The increase ended with the adoption of the CPSC rule, declining to 16.8 per 100,000 in 2001 and rising to 17.9 in 2003. CONCLUSIONS: This study's analysis suggests that the CPSC rule requiring child-resistant packaging on containers of mouthwash containing 3 g or more of ethanol has been successful in reducing AAPCC's reports of mouthwash overingestion. Health care providers should take a more active role by informing parents of the dangers associated with accidental ingestion of ethanol-containing mouthwash. Manufacturers should print warnings about the potential hazard of high ethanol concentrations on labels more prominent and they should stop producing mouthwashes with such high concentrations of ethanol. Moreover, they should also consider discontinuing packaging mouthwash in large containers.
