ABSTRACT
INTRODUCTION: The purpose of this study was to analyze displacement and stress distribution in the maxilla during maxillary expansion followed by protraction using bone-borne and conventional tooth-borne palatal expanders and a facemask via 3-dimensional finite element analysis. METHODS: A finite element model of an adolescent skull was created, and 4 different types of appliances were integrated into it: facemask (type A); facemask with paramedian bone-borne expander (type B), facemask with palatal-slope bone-borne expander (type C), and facemask with conventional expander (type D). Expansion of 0.25 mm followed by 500 g of force per side was applied. RESULTS: Type A showed anterior displacement of the dentition combined with downward displacement of posterior teeth and upward displacement of anterior teeth. The combination of protraction and expansion in type D showed the greatest anterior displacement. In types B and C, the expansion forces resulted in posterior displacement decreasing the net displacement of the combination. Stresses concentrated around the miniscrews in types B and C. In types A and D, stresses concentrated at the first premolar and first molar. Type B had the highest stresses followed by type C and then D. CONCLUSIONS: The conventional tooth-borne expander (type D) enhanced the effect of maxillary protraction. Facemask alone (type A) resulted in more anterior displacement of the maxilla than the combination of facemask and bone-borne expanders (types B and C). The clinician should be aware of the initial stresses and movements from different expanders with facemask found in this study and confirm the movements in future clinical Class III studies.
Subject(s)
Orthodontic Anchorage Procedures/instrumentation , Palatal Expansion Technique/instrumentation , Adolescent , Dental Stress Analysis , Extraoral Traction Appliances , Finite Element Analysis , Humans , Maxilla/anatomy & histology , Orthodontic Anchorage Procedures/methods , Orthodontic Appliance Design , Orthodontic AppliancesABSTRACT
Bisphosphonates have unique pharmacological characteristics unlike those of any other drug group. Millions of adults take oral bisphosphonates for long-term treatment of osteoporosis and osteopenia; some of these people will most likely also seek orthodontic treatment. Adverse dental effects from bisphosphonates have been reported, including decreased tooth movement, impaired bone healing, and osteonecrosis in the mandible and the maxilla. Osteonecrosis has been rarely observed after bisphosphonate use for osteoporosis. However, adverse drug effects might occur more frequently in orthodontic patients, and they would probably be noted before the end-stage pathology of osteonecrosis. Adverse effects during orthodontic treatment, including decreased tooth movement, could last for years after the drug therapy is stopped. Successful orthodontic treatment requires optimal bone healing to prevent excessive tooth mobility. Bisphosphonates appear to have two bone elimination rates - a fast elimination of weeks from the bone surface and a slow elimination of years after incorporation into the bone structure. This article presents methods to clinically and radiographically monitor orthodontic patients who are taking oral bisphosphonates. Efforts to minimize adverse effects and optimize orthodontic procedures with physician-approved drug holidays are discussed. The orthodontic treatment results of three patients who received bisphosphonate therapy are reported.
Subject(s)
Bisphosphonate-Associated Osteonecrosis of the Jaw/prevention & control , Bone Density Conservation Agents/pharmacokinetics , Bone and Bones/metabolism , Diphosphonates/pharmacokinetics , Orthodontics, Corrective/adverse effects , Administration, Oral , Aged , Bisphosphonate-Associated Osteonecrosis of the Jaw/diagnostic imaging , Bone Density Conservation Agents/administration & dosage , Bone Density Conservation Agents/adverse effects , Bone Density Conservation Agents/chemistry , Diphosphonates/administration & dosage , Diphosphonates/adverse effects , Diphosphonates/chemistry , Drug Administration Schedule , Female , Half-Life , Humans , Injections, Intravenous , Malocclusion, Angle Class II/therapy , Middle Aged , Osteoporosis, Postmenopausal/drug therapy , Osteosclerosis/chemically induced , Osteosclerosis/diagnostic imaging , Radiography , Tooth Extraction/adverse effects , Tooth Mobility/chemically inducedABSTRACT
Bisphosphonates have unique pharmacological characteristics unlike those of any other drug group. Millions of adults take oral bisphosphonates for long-term treatment of osteoporosis and osteopenia; some of these people will most likely also seek orthodontic treatment. Adverse dental effects from bisphosphonates have been reported, including decreased tooth movement, impaired bone healing, and osteonecrosis in the mandible and the maxilla. Osteonecrosis has been rarely observed after bisphosphonate use for osteoporosis. However, adverse drug effects might occur more frequently in orthodontic patients, and they would probably be noted before the end-stage pathology of osteonecrosis. Adverse effects during orthodontic treatment, including decreased tooth movement, could last for years after the drug therapy is stopped. Successful orthodontic treatment requires optimal bone healing to prevent excessive tooth mobility. Bisphosphonates appear to have 2 bone elimination rates--a fast elimination of weeks from the bone surface and a slow elimination of years after incorporation into the bone structure. This article presents methods to clinically and radiographically monitor orthodontic patients who are taking oral bisphosphonates. Efforts to minimize adverse effects and optimize orthodontic procedures with physician-approved drug holidays are discussed. The orthodontic treatment results of 3 patients who received bisphosphonate therapy are reported.
Subject(s)
Bone Density Conservation Agents/therapeutic use , Diphosphonates/therapeutic use , Osteoporosis/drug therapy , Tooth Movement Techniques , Adult , Aged , Bone Density Conservation Agents/adverse effects , Bone Density Conservation Agents/metabolism , Bone Diseases, Metabolic/drug therapy , Diphosphonates/adverse effects , Diphosphonates/metabolism , Female , Half-Life , Humans , Jaw Diseases/chemically induced , Jaw Diseases/prevention & control , Middle Aged , Osteonecrosis/chemically induced , Osteonecrosis/prevention & control , Osteosclerosis/chemically induced , Radiography, Panoramic , Risk Factors , Structure-Activity Relationship , Tooth Mobility/chemically induced , Treatment OutcomeSubject(s)
Bone Density Conservation Agents/adverse effects , Diphosphonates/adverse effects , Jaw Diseases/chemically induced , Osteonecrosis/chemically induced , Societies, Dental , Administration, Oral , Alveolar Process/metabolism , Bone Density Conservation Agents/administration & dosage , Bone Density Conservation Agents/pharmacokinetics , Diphosphonates/administration & dosage , Diphosphonates/pharmacokinetics , Dose-Response Relationship, Drug , Humans , Injections, Intravenous , Metabolic Clearance RateABSTRACT
The purpose of this article is to raise awareness among orthodontists of the effects of bisphosphonates, a commonly prescribed type of drug that can inhibit tooth movement and increase serious osteonecrosis risks in the alveolar bones of the maxilla and the mandible. Common medical uses of bisphosphonates, applicable pharmacology, pharmacokinetics, reports of impaired bone healing and induced osteonecrosis, and a drug effect accumulation theory are reviewed. Potential orthodontic issues and proposed orthodontic recommendations for intravenous and oral bisphosphonate treatments are discussed. Bisphosphonate medication screening, patient counseling, informed consent, and, perhaps, changes in treatment planning might be considered.