Sixteen-week analysis of unaltered elastomeric chain relating in-vitro force degradation with in-vivo extraction space tooth movement.

INTRODUCTION: The purposes of this study were to evaluate whether unaltered elastomeric chain can continue to move teeth for 16 weeks and to relate it to the amount of force remaining for the same batch of elastomeric chains. METHODS: The in-vivo portion of the study had a sample of 30 paired extraction space sites from 22 subjects who were measured for closure of the space every 28 days. The altered side elastomeric chain served as the control and was replaced at 28-day intervals whereas the experimental side remained unaltered. In the in-vitro portion of the study, 100 each of 2-unit and 3-unit segments of the same batch of elastomeric chains were placed in a water bath, and the force was measured for 20 of each segment length at the 28-day measurement points. RESULTS: Statistically significant amounts of space closure occurred at both the altered and unaltered sites at all measurement time points. The mean space closure at the altered sites was minimally greater than that observed at the paired unaltered sites. The mean differences of space closure between the altered and unaltered sites ranged from a minimum of -0.05 mm at 4 weeks to a maximum of -0.14 mm at 8 weeks. The elastomeric chain force degraded rapidly by 4 weeks but continued a gradual diminution of force to 86 g at 16 weeks. CONCLUSIONS: Unaltered elastomeric chain continued to move teeth into extraction spaces for 16 weeks in this sample from both statistically and clinically significant standpoints. There were minimal and statistically insignificant differences in the mean space closure measurements between the paired altered and unaltered sites. The elastomeric chain force at 16 weeks was less than 100 g, yet at the same time point, teeth continued to move clinically.

Long-term bonded retention after closure of maxillary midline diastema.

INTRODUCTION: The objectives of this study were to evaluate fixed bonded palatal surface retainers between the maxillary central incisors that were placed to maintain midline diastema closure and record their longevity, proclivity for damage, and periodontal health of the central incisors in patients 5 or more years after treatment. METHODS: Twenty-nine subjects were contacted and interviewed by phone concerning the status of their bonded retainer and midline diastema. Eleven subjects with intact retainers came for a periodontal health evaluation of the maxillary central incisors. The measures used were the plaque index, the periodontal screening and recording score, and the gingival index. A split-mouth design was used. Statistical analyses of retainer duration, damage probability, and gingival health were performed. RESULTS: Of the 29 subjects, 52% of the initial retainers were in place for an average of 23 years. For the total of 34 bonded retainers, the mean longevity was 17 years. The risk of breakage for any particular year the retainer was in place was 2%. The mean differences in scores between the maxillary central incisors and the control teeth were -0.06 for the plaque index, -0.14 for the periodontal screening and recording score, and -0.11 for the gingival index. Statistical tests on the differences indicated no evidence that the long-term presence of the bonded palatal surface retainer adversely affected the periodontal health of the maxillary central incisors. CONCLUSIONS: The study's sample demonstrated that a bonded retainer for maintaining closure of a maxillary midline diastema can last an average of 17 years or more, with a yearly 2% chance of breakage and with no expected adverse effects on the periodontal health of the maxillary central incisors.

A report of the ABO Resident Clinical Outcome Study (the pilot study).

INTRODUCTION: A 4-year collaborative project between the American Board of Orthodontics (ABO) and 15 American orthodontic graduate programs concluded at the ABO Clinical Examination in February 2006. METHODS: Fifty recent graduates (the pilot study group) presented cases that were treated in their graduate programs as partial fulfillment of the requirements for ABO certification. The examinees were tested by calibrated ABO examiners and required to satisfy traditional ABO standards. They presented appropriate case reports that contained the ABO's 3 measurement instruments. Thirty-nine practicing orthodontists (the control group) presented cases according to the traditional ABO Clinical Examination process. RESULTS: Ninety percent of the pilot study group and 85% of the control group successfully accomplished ABO certification. There was a difference of 2.38 points between the 2 groups for the mean total scores of the cases that passed. The pilot study group presented cases that met the historic averages for case complexity (discrepancy index). CONCLUSIONS: Residents in orthodontic programs are able to treat cases to ABO standards of quality.

The American Board of Orthodontics: Diplomate recertification.

Although some specialty certifying boards began recommending or requiring recertification of their "boarded" specialists as early as 1986, recertification is a relatively new concept for the specialty of orthodontics. In the mid 1990s, the American Board of Orthodontics (ABO) recognized that many other medical and dental specialty boards had already established voluntary or mandatory recertification policies and decided to establish its own time-limited certifying policy. After a series of field tests involving former directors, council members of the College of Diplomates of the ABO, and volunteer diplomates, the ABO instituted a recertification policy for candidates who applied for initial certification after January 1, 1998. Since then, the total number of diplomates who have been recertified has steadily increased. Surveys of successfully recertified diplomates reflect a positive feeling about the process. When medical and dental specialists are expected to be more accountable, recertification has been shown to be a valid method to help ensure continued competency. The ABO believes that the formulation of educational and certifying processes to document a diplomate's clinical competency throughout his or her career will help to serve the public welfare. The ABO is attempting to make initial certification and periodic recertification attainable for more orthodontists and, in so doing, to provide a standard by which we exist as a specialty.

The ABO discrepancy index: a measure of case complexity.

A criterion for determining the acceptability of a case presented for the American Board of Orthodontics (ABO) Phase III clinical examination is case difficulty. Case difficulty can often be subjective; however, it is related to case complexity, which can be quantifiable. Over the past 5 years, the ABO has developed and field-tested a discrepancy index, made up of various clinical entities that are measurable and have generally accepted norms. These entities summarize the clinical features of a patient's condition with a quantifiable, objective list of target disorders that represent the common elements of an orthodontic diagnosis: overjet, overbite, anterior open bite, lateral open bite, crowding, occlusion, lingual posterior crossbite, buccal posterior crossbite, ANB angle, IMPA, and SN-GoGn angle. The greater the number of these conditions in a patient, the greater the complexity and the greater the challenge to the orthodontist. The ABO is considering several options for applying the discrepancy index to the Phase III clinical examination.