Combined orthodontic and surgical open bite correction: Principles for success. Part 2.

OBJECTIVES: To present a clinical description of the team's treatment techniques. MATERIALS AND METHODS: In Part 1, 30 patients underwent segmental maxillary orthodontics, multisegment Le Fort I, and bilateral sagittal osteotomies of the mandible. Part 1 reported excellent occlusal stability at a mean follow-up of 49.43 months (range, 36-92 months). Cases presented in Part 2 were selected based on availability of excellent technique photographs. The same techniques described in Part 2 cases were used on all Part 1 patients. RESULTS: The coordination of arch widths and forms, overbite, overjet, and maxillary curve of Spee corrections were stable using the team protocols for orthodontic and surgical treatment. CONCLUSIONS: In the study group, long-term three-dimensionally stable occlusal results were achieved. To duplicate these results, specific orthodontic preparation, intraoperative surgical steps, and postsurgical steps must be carefully planned and executed. These steps are described in this article, Part 2.

Combined orthodontic and surgical open bite correction.

OBJECTIVES: To examine the stability of combined surgical and orthodontic bite correction with emphasis on open-bite closure. All study patients were treated with strict and consistent orthodontic and surgical protocols. MATERIALS AND METHODS: Study inclusion required all patients to have anterior open bites, maxillary accentuated curve of Spee, 36-month minimum follow-up, and no temporomandibular joint pathology. Thirty patients met the inclusion/exclusion criteria. Importantly, segmental upper arch orthodontic preparation (performed by EG) was used. Surgery consisted of a multisegment Le Fort I (MSLFI) combined with a bilateral sagittal osteotomies (BSSO). Surgery was performed (by ADA and LT) at the Department of Dentistry and Maxillofacial Surgery of the University of Verona, Italy. RESULTS: The long-term open bite and overjet relapse were not statistically significant. The mean transverse relapse of the upper and lower molars was statistically significant. Of great importance, the upper and lower arch widths narrowed together, maintaining intercuspation of the posterior dentition which prevented anterior open bites from developing. CONCLUSIONS: This study revealed stability of three-dimensional occlusal correction including anterior open bite. Stable open bite closure was achieved by using rigid protocols for orthodontic preparation, surgical techniques, surgical follow-up, and orthodontic finishing.

Evolution of treatment mechanics and contemporary appliance design in orthodontics: A 40-year perspective.

Until the early 1970s, successful treatment with the Begg technique and the Tweed edgewise technique required tedious wire bending. The introduction of Andrews' straight wire appliance changed that, and it was one of the most significant contributions in the history of orthodontics. The straight wire appliance significantly reduced the amount of wire bending and also brought along other options in treatment mechanics. Retraction of the canines with elastic chains and ligature wires became more common. Sliding mechanics in place of closing loops became the method of space closure for a significant number of clinicians. Edgewise force levels were initially used to close spaces; however, it was soon observed that lighter forces were more effective with sliding mechanics. Along with these changes, it became apparent that compensation in the appliance was needed, depending on the type of malocclusion and particularly with varying extraction sequences. Various appliance designs were developed to accommodate changes in mechanics and force levels. These modifications improved tooth positions at the end of treatment as long as the brackets were properly placed. These major changes in appliances, force levels, and treatment mechanics can be traced back to the work of Dr Lawrence Andrews and the straight wire appliances.

Comparison of arch forms between Israeli and North American white populations.

INTRODUCTION: Identification of the dental arch form of the orthodontic patient is a key aspect for achieving a stable, functional, and esthetic dentition. Failure to customize preformed archwires with the patient's arch form might increase the probability of relapse and lead to an unnatural smile. The primary objective of this study was to identify the arch forms of Israeli subjects with dental normocclusion and malocclusions. The secondary objective was to clarify the morphologic differences between Israeli and North American white subjects with various malocclusions. METHODS: The sample included 134 Israeli (40 Class I, 61 Class II, and 33 Class III) and 160 North American (60 Class I, 50 Class II, and 50 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth based on mandibular tooth thickness data. Four linear and 2 proportional measurements were made. The dental arches were classified as square, ovoid, and tapered forms to determine and compare the frequency distributions between the 2 ethnic groups. RESULTS: The most frequent mandibular arch form of the Israeli group was found to be ovoid as opposed to tapered in the North American white group. The white population had statistically significant decreased arch widths and increased arch depths compared with the Israeli population. The analysis of the Israeli sample indicated that, as the malocclusion shifts from Class III through Class I to Class II, the weight of the arch form tends to shift from square and ovoid to ovoid and tapered. CONCLUSIONS: Our results suggest that, when treating Israeli patients, one should expect to use the preformed ovoid arch form orthodontic wires in a significant percentage of patients.

Redefining orthodontic space closure: sequential repetitive loading of the periodontal ligament--a clinical study.

AIMS: To assess the rate of tooth movement, anchorage loss, root resorption, and alkaline phosphatase (ALP) activity in the gingival crevicular fluid (GCF) as a marker for bone remodeling during orthodontic space closure using two different mechanisms. METHODS: Space closure was completed in 20 patients with extraction of all 4 premolars. Lateral cephalograms and radio-visiographs taken before (T1) and after (T2) space closure were assessed for anchorage loss and root resorption. Alkaline phosphatase levels were measured in 10 patients, which were divided into two groups of five each. Spaces were closed with a screw device in the first group and with active tie-backs in the second. Gingival crevicular fluid samples, collected at intervals, were assayed for alkaline phosphatase spectrophotometrically in each patient. RESULTS: The mean rate of tooth movement was 1.32 ± 0.22 mm/month. The mean amount of anchorage loss in the maxilla and mandible was 1.23 ± 0.60 mm and 1.08 ± 0.65 mm, respectively. Sixty (25%) roots showed no root resorption, while 180 (75%) roots displayed mild to moderate blunting of their apices. Gingival crevicular fluid-alkaline phosphatase level increased significantly from day 7 to day 28 in both groups, but significantly more in the screw retraction group (P<.05). CONCLUSION: It is possible to infer that space closure occurs more rapidly with sequential repetitive loading of the periodontal ligament than with conventional active tie-backs. This observation is in concurrence with a significant increase in the gingival crevicular fluid-alkaline phosphatase level.

Comparison of arch forms between Korean and North American white populations.

The purpose of this study was to evaluate morphologic differences in the mandibular arches of Korean and North American white subjects. The subjects were grouped according to arch form (tapered, ovoid, and square) to compare the frequency distribution of the 3 arch forms between the ethnic groups in each Angle classification. The sample included 160 white (60 Class I, 50 Class II, and 50 Class III) and 368 Korean (114 Class I, 119 Class II, and 135 Class III) subjects. The most facial portion of 13 proximal contact areas was digitized from photocopied images of the mandibular dental arches. Clinical bracket points were calculated for each tooth according to mandibular tooth thickness data, and then 4 linear and 2 proportional measurements were taken. Arch width was statistically significantly smaller in the white group than in the Korean group, but arch depth did not differ. In the Korean group, the most frequent arch form was square, whereas in the white group the tapered arch form predominated. When the subjects were regrouped by arch form, the Korean arches had a tendency to be larger and deeper than the white arches within each of the 3 arch form types.