Dental compensation for moderate Class?III with vertical growth pattern by extraction of the lower second molars

Objectives

Analysis of the effects and side effects of treatment of patients with moderate skeletal Class?III and vertical growth pattern by means of extraction of the second molars in the lower jaw.

Patients and methods

A total of 20 patients with a mean age of 12.9 years were examined retrospectively. Inclusion criteria consisted of a Wits value of 0 to ?5, a posterior growth pattern of the mandible (Hasund analysis), an overjet of ?2 to 1?mm, and an overbite of 0 to ?3?mm. Treatment was performed using a straight-wire appliance. As part of the treatment, the lower second molars were extracted and Class?III elastics attached. Cephalograms and orthopantomograms taken before and after treatment were used for evaluation.

Results

Treatment resulted in a significant change in the mean overjet from 0.5?mm to 2.1?mm and the attainment of a positive mean overbite of ?1.0?mm to 0.9?mm. The occlusal plane rotated anteriorly from 18.8° to 13.7°. The skeletal parameters showed a change in the Wits value from ?3.3?mm to ?1.4?mm and an anterior mandibular rotation (ML-NSL 35.5° vs. 32.0°). The soft tissues revealed an increase in the distance between the lower lip and the ??esthetic line?? to the posterior (?2.0?mm vs. ?3.9?mm).

Conclusion

Dental compensation of moderate skeletal Class?III with a tendency to an anterior open bite with vertical growth pattern by extracting the lower second molars, combined with Class III elastics, resulted in an anterior rotation of the occlusal plane and mandible. Eighteen of 20 patients achieved a physiological overjet and positive overbite. A prerequisite for this therapy is the presence of lower wisdom teeth; a potential side effect is elongation of the upper second molars.     

Orthodontic treatment of patients medicated with bisphosphonates—a clinical case report

Introduction

Bisphosphonates (BP) are an established medication, e.g., for the prevention/therapy of osteoporosis. The effects of the changed bone metabolism for orthodontic treatments are unknown.

Case report

A 66-year-old woman underwent a total oral rehabilitation. The therapy included (1) tooth extractions, (2) periodontal treatment, (3) insertion of dental implants, (4) provisional implant restorations, (5) orthodontic treatment, and (6) definite implant restorations. The orthodontic tooth movements were in- and retrusion of the upper frontal teeth, intrusion of the lower front teeth, using the dental implants as skeletal anchorage. After implant insertion and one month before beginning the orthodontic treatment, osteoporosis was diagnosed in this patient and, without notification to our facility, BP treatment was initiated by her general practitioner (alendronate oral, 70 mg/week), with an overall duration of intake of 7 months. After 13 months, the orthodontic treatment was successfully accomplished; however enlarged periodontal gaps, sclerotic bone areas, and mild apical root resorptions of the upper frontal teeth were found in this patient.

Conclusion

Currently, there are no recommendations for orthodontic patients undergoing BP therapy. Orthodontic tooth movement in this low-risk patient with a short duration of intake and a low-dose BP medication was possible. Because of the reduced bone metabolism and the higher amount of side effects, the treatment should be performed with extremely light forces and frequent monitoring.     

Lumbar motion-sparing surgery

Surgical treatment of the painful lumbar spine segment is a challenging endeavor. The ideal surgical intervention has a predictably good clinical effect, a low incidence of complications, and long-term durability. The gold standard for surgical intervention is a lumbar spine fusion, but the long-term durability of lumbar fusions is compromised with the development of adjacent level degeneration. Due to these concerns, motion-sparing surgical implants, including artificial discs, dynamic stabilization techniques, and nucleus pulposus replacements, have been developed to simultaneously treat the painful motion segment while at the same time preserving sufficient motion to decrease the chances of adjacent level degeneration.     

Validity of geographically modeled environmental exposure estimates

Geographic modeling is increasingly being used to estimate long-term environmental exposures in epidemiologic studies of chronic disease outcomes. However, without validation against measured environmental concentrations, personal exposure levels, or biologic doses, these models cannot be assumed a priori to be accurate. This article discusses three examples of epidemiologic associations involving exposures estimated using geographic modeling, and identifies important issues that affect geographically modeled exposure assessment in these areas. In air pollution epidemiology, geographic models of fine particulate matter levels have frequently been validated against measured environmental levels, but comparisons between ambient and personal exposure levels have shown only moderate correlations. Estimating exposure to magnetic fields by using geographically modeled distances is problematic because the error is larger at short distances, where field levels can vary substantially. Geographic models of environmental exposure to pesticides, including paraquat, have seldom been validated against environmental or personal levels, and validation studies have yielded inconsistent and typically modest results. In general, the exposure misclassification resulting from geographic models of environmental exposures can be differential and can result in bias away from the null even if non-differential. Therefore, geographic exposure models must be rigorously constructed and validated if they are to be relied upon to produce credible scientific results to inform epidemiologic research. To our knowledge, such models have not yet successfully predicted an association between an environmental exposure and a chronic disease outcome that has eventually been established as causal, and may not be capable of doing so in the absence of thorough validation.