Comparison of treatment effects with labial and lingual fixed appliances.

Pretreatment and posttreatment lateral cephalometric radiographs were evaluated for 120 patients--40 from each of three private practices. Twenty patients from each office had been treated with labial fixed appliances and 20 with lingual fixed appliances. There were no significant differences between labial and lingual appliances with respect to the change of any cephalometric measurement during treatment (posttreatment value minus pretreatment value). Differences among patients from the three offices were found only for upper incisor vertical position, and these appeared to reflect differences in treatment objectives rather than in appliances. However, several significant differences were found when changes during treatment were evaluated according to extraction pattern, without reference to the type of appliance used. There was no evidence that the mechanics required with lingual appliances necessarily led to any changes in treatment results, as determined by the cephalometric measurements used in this study.

Treatment of adults with lingual orthodontic appliances.

With the advent of lingual orthodontic treatment, an alternative became available to the adult patient who preferred to avoid the unesthetic appearance of conventional orthodontic appliances. The newer brackets and archwires described in this article, in combination with the proven technique developed by the author and others, has made lingual orthodontic treatment a practical reality. The appliance has been shown to be as effective as labial counterparts in correcting all types of malocclusions. New laboratory and indirect bonding techniques have eliminated the need for intricate wire bending and have reduced patient chair time and overall treatment time. Because of the premature introduction of early lingual appliances, many dental practitioners mistakenly believe that lingual treatment is less effective than labial treatment. As more examples of successful treatment are seen, dental practitioners will be more apt to refer patients to orthodontists proficient in this technique. Many graduate orthodontic programs now are teaching this technique to their residents. About 3000 patients currently are starting treatment with lingual appliances each year. This represents only about 1 per cent of adult patients. It is projected that this slowly will climb to about 10 per cent of adult orthodontic treatment over the next 5 years. The increased cost of this treatment, coupled with the resistance on the part of many orthodontists to learn the new technique, seem to be the limiting factors.

Hemolytic and antigenic measurements of complement. A comparison of serum and plasma samples in normal individuals and patients.

Over a 2-year period we evaluated 10 patients with a discrepancy between functional and antigenic assays in the routinely employed clinical assays for measuring serum complement concentrations. These differences were shown to be secondary to cold-dependent activation of the classical complement pathway in vitro, in some cases by cryoglobulins and in others by unknown means. Plasma samples were procured with commonly used anticoagulants (EDTA, citrate, or heparin) that prevent in vitro complement activation. To assess whether plasma samples were suitable for complement determination, a comparison of serum vs. plasma samples for THC, C4, C2, C3, factor B, and C6 levels in normals and patient populations was undertaken. Only modest differences were found between serum and plasma samples for these functional and antigenic assays except for heparinized samples in which determinations by rate nephelometry produced falsely elevated C4, C3, and factor B antigenic levels. Thus plasma samples, especially EDTA or citrate, are suitable for complement determinations and could be used either routinely or, more selectively, in patients in whom there is a discrepancy between functional and antigenic determinations.

Cold dependent activation of complement in systemic lupus erythematosus. A unique cause for a discrepancy between clinical and laboratory parameters.

A 31-year-old woman with systemic lupus erythematosus (SLE) was studied because she developed markedly reduced total hemolytic complement activity at a time when her disease was clinically inactive. Functional assays demonstrated reduced activities of C1, C4, and C2, but normal concentrations of C3 and the terminal (C5-9) components were present. Antigenic concentrations of C1, C4, and C2 were normal. Plasma or serum obtained from blood allowed to clot at 37 degrees C had normal complement activity. Complement activity was depleted when the patient's serum was incubated in the cold. At reduced temperatures, the patient's serum (or purified IgG) depleted complement activity of normal human sera. A second patient with SLE was also demonstrated to have this same phenomenon. Cryoglobulins were not detectable in these patients. These data indicate that in vivo the patients' complement was normal and that the observed in vitro reduction was caused by cold dependent activation of the classical pathway.