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A method of planning orthodontic treatment in the transverse plane has been presented. The occlusogram procedure outlined augments other orthodontic records in order to define more specifically the requirements of successful orthodontic treatment. Anchorage requirements, extractions, if any, and arch widths plus the final occlusal relationships can be determined at the outset of orthodontic treatment.
In establishing the validity of an index for identifying individuals needing orthodontic treatment, we must concern ourselves with the construct validity of the measure. Since it is clear that the relevant theory concerning need for treatment must include esthetics and the accompanying social and psychological characteristics, the construct validation of an index to measure need for treatment must include tests of hypotheses with these dimensions. If we consider a child's self-perception of occlusion as a psychological variable and another person's perception of a child's occlusion as a social variable, theory relevant to an index of need for treatment would hypothesize that each should correlate positively with need for treatment. Subjects were eighth and ninth grade students from a metropolitan area in western New York State. Fifty-two of the children were planning to obtain orthodontic treatment, and 102 were not. Data were also obtained, whenever possible, from both parents and from a sibling (if any) nearest in age to the child. Data were collected in one session by a trained interviewer who used a structured interview and also photographed the child's teeth and jaws. In addition, the child was given an orthodontic Treatment Priority Index (TPI) examination by a dentist enrolled in a graduate program in orthodontics, who had previously been trained and standardized in the use of the TPI. In addition, to the TPI, scores obtained included three psychological measures and eight social measures. Each of the psychological and social variables correlated significantly with TPI at the 0.05 level, with values ranging from 0.21 to 0.54 and a median value of 0.42. On the basis of these correlations, evidence is presented for the construct validity of the TPI when measuring need for treatment.
The mechanical strength of the periodontium was examined by extracting the rat mandibular first molar from its socket in the dissected jaw following application of orthodontic forces. Rubber elastic bands of increasing sizes were inserted between the first and the second molars and following injections of anti-inflammatory drugs, hydrocortisone and indomethacin for 7 days. Marked decreases of the mean ultimate loads to extract the teeth were found following application of the orthodontic forces. Increases of the ultimate loads were found following injections of hydrocortisone and indomethacin. The distances pulled to reach the ultimate loads which seem to represent the extensibility and elasticity of the periodontium correlated closely with the ultimate loads. The orthodontic forces applied were estimated to be about 0.7 kilograms at the end of the experimental period. It was suggested that the mechanical strength of the periodontium is maintained by the organization and constitution of the periodontal collagen fibers, and by the attachment of fibers to the bone, which could be affected by orthodontic forces and by anti-inflammatory drugs.
Bimaxillary protrusion can be treated effectively in growing patients and in adults with conventional orthodontic therapy. In the adult patient, however, combined surgical and orthodontic treatment modalities may offer distinct advantages over such conventional therapy. Treatment time and possible adverse effects of lengthy and extensive orthodontic therapy may be reduced and optimum esthetic improvement may be facilitated. Those cases that exhibit severe skeletal discrepancies in the vertical, transverse, or sagittal dimensions in addition to dentoalveolar protrusion may be best treated in this manner to simultaneously correct all existing problems and obtain optimal esthetic and functional results. This article delineates the rationale for such therapy and tridimensional diagnostic and treatment-planning considerations from both the orthodontic and surgical standpoints. Case reports illustrate clinically the results obtainable with such treatment.
Utilization of orthodontic services may be influenced as much by the social and cultural setting as by objective criteria. The public's assessment of dental irregularity and its perceptions of the psychosocial implications of malocclusion may be critical factors in the utilization of available services. To test these assumptions, two communities with historic differences in the availability and utilization of orthodontic services were selected as survey sites (Lexington, Kentucky, and Cardiff, Wales). Three-hundred eighty-five sixth grade children (11 to 12 years of age) and 123 of their parents were interviewed concerning dental esthetics, treatment need, and knowledge about, attitudes toward, and value placed on orthodontic treatment. Although the Lexington respondents had greater personal and indirect knowledge about such services, they did not have more positive perceptions about treatment; nor did they value straight teeth more highly. There were no significant differences between the groups' judgement of dental esthetics or assessment of treatment need. The differences in utilization of services in the two communities could not be explained in terms of differences in attitude toward malocclusion and orthodontic treatment.
Enamel demineralization occurring adjacent to directly bonded orthodontic attachments is of great concern to orthodontists. The topical application of fluorides to enamel surfaces before acid etching and the bonding of the attachments is not recommended by many investigators. The objective of this study was to determine the enamel fluoride acquired from various topical fluoride agents and to determine the effect of the acquired fluoride on the tensile bond strength of an orthodontic bonding system. Fifty extracted maxillary central incisors were mounted in cups and the facial surfaces of the crowns were polished on 600-grit silicon carbide paper. Enamel microbiopsies were performed just off the midpoint of each tooth. Ten teeth served as controls and received no topical fluoride treatment, while a similar number were treated with either APF, SnF2, Duraphat, or Fluor Protector. The teeth were suspended in synthetic saliva 4 minutes after fluoride application. The topical fluoride agents were removed after 24 hours and the teeth were again suspended in synthetic saliva at 37 degrees C for 7 days. Enamel biopsies were again performed just off the midpoint of each tooth on the side not previously biopsied. The enamel surfaces were etched for 1 minute and the tensile bond strength of Concise orthodontic bonding system to the etched enamel surfaces was determined. The enamel surfaces acquired significantly different amounts of fluoride from the topical fluoride agents, but the bond strengths to these surfaces were not significantly different. The results of this in vitro study suggest that the application of topical fluoride agents to enamel surfaces 7 days before the bonding of orthodontic attachments will not have an adverse effect on bond strength.
A survey concerning the orthodontic management of patients with a history of rheumatic fever or congenital heart disease was mailed to a random sample of 500 orthodontists throughout the United States. Two hundred thirty-two surveys were completed and returned. Analysis revealed that 88% of the respondents were aware that they should screen for patients with a history of rheumatic fever or congenital heart disease, only 11% used the antibiotic regimen recommended in 1977 by the American Heart Association (see Fig. 2), one half of the respondents thought it was necessary to provide antibiotic coverage during banding, and 38% deemed it necessary for debanding procedures which were likely to cause some degree of bleeding from the gingival sulcus. Only one half of the respondents would discontinue treatment if a condition of gingivitis developed which did not show signs of improvement, and only 70% provided medication for orthodontic procedures that could result in bacteremia. Furthermore, the results of this survey indicated that there was a great variation in the antibiotic regimen of orthodontic treatment for patients at risk of developing endocarditis and that there was a need to make the orthodontist more aware of the 1977 recommendations of the American Heart Association. Finally, a comparison between the year of graduation from an orthodontic program and the number of respondents who did not screen for or did not premedicate at-risk patients revealed a direct relationship. The earlier the education, the smaller the number of respondents who screened or premedicated.(ABSTRACT TRUNCATED AT 250 WORDS)
The prevalence of enamel decalcification beneath orthodontic bands has indicated the need for a fluoride-releasing, enamel-adhesive orthodontic luting cement. The purpose of this study was to compare the retentive bond strengths of orthodontic bands cemented with two new fluoride-releasing cements, a zinc polycarboxylate and a glass ionomer, with the retentive bond strength of bands cemented with the standard orthodontic cement zinc phosphate. The site of cement failure was also evaluated. One hundred eighty extracted human molar teeth were embedded in resin blocks and randomly assigned to three cement groups. Adapted bands were cemented by a clinically acceptable technique. The cemented teeth were then assigned to one of three time intervals--24 hours, 7 days, and 60 days--and thermocycled in synthetic saliva. The force required to initially fracture the cement bond was used as a measure of cement retention. By means of the Instron, a tensile load was applied to each cemented band. The maximum retentive strength (cement failure) was interpreted from the stress-strain curve at the point where linearity deviated. The failure site was judged subjectively: between cement and enamel, within the cement, or between cement and the band. Using stress at failure, an analysis of variance showed no significant differences among the retentive strengths of the three cements. The chi-square test revealed a significant difference (P less than 0.01) between failure sites of the zinc phosphate and glass ionomer cements. Significantly more bands cemented with the glass ionomer failed at the cement/band interface, leaving the cement adhered to the tooth.(ABSTRACT TRUNCATED AT 250 WORDS)
In orthognathic surgery cases the treatment objectives, extraction patterns, and types of mechanics used are frequently the reverse of those used in conventional orthodontics. Thus, starting cases orthodontically and then, if unsuccessful, referring them for surgery often produces compromised results. Presurgical intra-arch objectives include positioning of the incisors in "ideal" positions, establishment of correct torque, and elimination of tooth-size discrepancies so as to permit the establishment of Class I canine and molar relationships after surgery. Presurgical objectives in the sagittal plane focus on removal of dental compensations. This may require the use of Class III elastics in Class II cases (and vice versa), thus allowing for maximal surgical correction of the underlying skeletal deformity. In the transverse plane, differentiation of skeletal from dental problems as well as identification of relative and absolute discrepancies should be carried out presurgically. Lateral corticotomies or segmental maxillary procedures should be used, depending on individual circumstances. Presurgical objectives in the vertical plane include maximizing the amount of presurgical orthodontic treatment carried out in open bites and minimizing the presurgical mechanics in deep bites. Encouragement of opening mandibular rotation at surgery while avoiding an increase in posterior face height contributes to stability. Orthodontic mechanics should not always include presurgical leveling of the curve of Spee and should actively avoid movements that may cause relapse tendencies. Careful attention to the use of surgical arch wires and splints during surgery and fixation, along with controlled elastic therapy and exercise programs after fixation, can greatly facilitate treatment.
Persons with mandibular deficiency and Class II malocclusions have a spectrum of esthetic, skeletal, and occlusal characteristics. In many of these patients optimal overall results are best obtained via a combined orthodontic-surgical approach. In such cases a critical patient evaluation is essential to decide (1) the optimal operation and (2) the appropriate orthodontic-surgical sequencing. In Part I of this article our method of making these two basic decisions is presented, the decisions being predicated upon achieving optimal esthetic, functional, and stable results. In addition, two of the possible orthodontic-surgical approaches--the augmentation genioplasty and the anterior maxillary ostectomy are discussed in detail. These approaches are illustrated with representative cases. In Part II of the article additional options for combined orthodontic surgical-management of this patient population will be discussed.
This paper describes a new simulation method to analyze the initial behavior of the total system comprising orthodontic appliance, teeth, and their supporting structures. It is based on a finite element method which additionally takes account of a rotational degree of freedom. Beam and rod elements are used for finite element idealization of orthodontic appliance. Through spring elements it is connected with the teeth supported by the alveolar structures. The technique of 'initial strain' is introduced so as to analyze the effects of a gable bend and activation on the force system which is delivered by the orthodontic appliance. As compared with the photoelastic technique hitherto used, this method serves to investigate systematically and quantitatively the initial aspect of orthodontic tooth movement.
Clearly, there are postpubertal patients with Class II malocclusions for whom orthognathic surgery combined with orthodontics is the "best" option, but epidemiologic information suggests they are a relatively small percentage of the potential patient pool. The majority of patients fall into either an orthodontic treatment group or a borderline category. Many of these can be treated successfully with orthodontic camouflage. Research has shown psychosocial factors play a major role in determining the patient's selection of a treatment option. This emphasizes the need for careful attention to global psychologic factors, with special emphasis on patient concerns regarding body image. Morphometric criteria have been offered describing appropriate candidates for orthodontic camouflage. These are supported by a combination of research and clinical experience. Patients who do not fit these criteria should not automatically be considered candidates for surgery. Psychosocial research suggests a percentage of these individuals place less importance on facial change and are content to improve dental esthetics and function to the degree possible. To assist in the decision-making process, patients should be given the best information available regarding potential outcome. Currently this may involve treatment simulation using a combination of computer images and dental models. Caution has been suggested, given the variability associated with predicting soft tissue change. There are additional legal concerns regarding the implied guarantee of treatment outcome. Correspondingly, the influence of this technology must be kept in perspective. Recent research on the decision-making process found computer imaging to be an important factor in only 24% of the patients studied.(ABSTRACT TRUNCATED AT 250 WORDS)
Prior to 1987, dental practitioners in England and Wales intending to carry out all but the simplest orthodontic treatment within the National Health Service, were required to submit pretreatment study models, details of the orthodontic assessment and the proposed treatment plan to the Dental Estimates Board prior to starting treatment. Models taken at the end of treatment were required by the Board to enable payment to be made. In this pilot study, the acceptability of orthodontic treatment plans used by practitioners working in the General Dental Services was assessed by eight hospital consultants, using information about 40 cases submitted to the Dental Estimates Board in 1987/88. All consultants considered a high proportion of plans to be unacceptable, but agreement between the consultants was variable and some agreed with one another on very few plans. A single scorer used the weighted PAR (Peer Assessment Rating) index to assess the degree of departure from normal occlusion of both pre- and post-treatment models. Using accepted standards, only nine cases were greatly improved (PAR reduction > 70%) and the mean percentage reduction in PAR score was low. Consultant opinion on the appropriateness of treatment planning was not related to the outcome of orthodontic treatment.
In orthodontic treatment of certain cases of tooth loss, aplasia, or ectopia, autotransplantation is sometimes a valid treatment alternative and often provides an improved result, compared to conventional orthodontic treatment, if an appropriate donor tooth is available and the anatomic circumstances permit it. However, in some cases autotransplantation is not immediately possible as a one-step procedure. In such cases cryopreservation provides a clinically useful technique when an extraoral storage period of months or years is needed to orthodontically prepare the recipient region. In the present case a mature upper first left premolar was stored for 18 months. During this period sufficient space was achieved in the contralateral recipient region between the upper left first and second premolars. The thawed graft was autotransplanted to this position. Endodontic treatment was initiated 4 weeks after transplantation. Four years after transplantation, the periodontal healing of the grafted tooth appeared clinically and radiographically normal without any signs of root resorption. The presented case demonstrates the capacity of a cryopreserved tooth to regenerate what seems to be a normal periodontium after transplantation. If these findings are confirmed in further clinical trials, the technique could be a valuable tool in future orthodontic treatment planning.
The effect of professional prophylaxis on the periodontium was studied in 14 adolescent orthodontic patients while under active treatment using a split-mouth experimental design. A full-banded appliance was used on all of the patients. The following variables were examined: plaque registration, gingival index, gingival migration, and width of the attached gingiva. Professional rubber-cup prophylaxis was performed on the test side of all patients together with reinforced oral hygiene instruction on a monthly basis. Measurements for the plaque registration, gingival index, gingival migration, and the width of the attached gingiva were recorded at the initial visit (baseline records), the 6-month evaluation, and the 10-month evaluation. Monthly registrations were completed for the plaque deposits and gingival inflammation at each of the 11 visits. All measurements were taken at the midfacial surface of the selected teeth. Four conclusions can be drawn from the findings of this study: the presence of an orthodontic appliance did not result in an increase of plaque accumulation or gingival inflammation for the full-banded orthodontic patient; monthly oral hygiene instruction was effective in significantly reducing the amount of visible plaque and gingival inflammation; monthly rubber-cup prophylaxis had a significant effect in reducing the gingival enlargement routinely associated with a fixed orthodontic appliance; and the width of attached gingiva showed no significant change throughout the course of the study.
This article reports a 10-year longitudinal investigation of symptoms attributed to temporomandibular joint dysfunction in orthodontically treated subjects. The study was designed to test the prevailing assumption that orthodontic therapy is an etiologic factor in inducing TMJ dysfunction. Although the study was prospective in design, several unexpected methodologic complications limited the data analyses. Presumed joint dysfunction symptoms were assessed in orthodontically treated subjects. The presumed symptoms were subsumed under three categories: subjective symptoms, objective symptoms, and x-ray findings. The prevalence of symptoms was analyzed before treatment, 4 years later subsequent to retention, and 10 years after the initiation of the study. Comparisons of symptom frequencies were made between Begg and activator-treated subjects. The results of this investigation led to the following conclusions. In studying temporomandibular joint dysfunction, subjective symptoms, objective symptoms, and x-ray findings should be analyzed separately. Registration of symptoms during orthodontic treatment should probably be attributed to age changes rather than to treatment procedures. Begg Class I and Class II treatments do not reduce the percentages of symptoms registered. Begg Class I and Class II treatments do not affect the incidence of subjective symptoms. Begg Class I and Class II treatments do not affect the incidence of x-ray findings. Begg Class I and Class II treatments create higher percentages of objective symptoms after retention, but not in the long run (10 years). Ten years after the beginning of treatment, the initial differences in symptomatology between activator and Begg children no longer exist.
Loss of periodontal bone support was examined in 24 patients orthodontically treated for pathologic tooth migration in one jaw. Prior to orthodontic realignment of the front teeth, the patients had received periodontal treatment. Active appliance therapy was not given until inflammation was eliminated and the patients demonstrated a high level of oral hygiene. A 0.020-inch spiral wire was bonded to each adjacent realigned tooth for retention. The levels of marginal bone of the front teeth in the treated and untreated jaws were measured in percentage of "maximum bone height" on periapical radiographs made before and after treatment. Relapse was evaluated from study models. Mean averaged loss of periodontal bone from the period before to after orthodontic treatment was 4.94% (SD 4.03, P less than 0.001) and 2.69% (SD 3.66, P less than 0.001) of the treated and untreated front teeth, respectively. The mean difference in averaged loss between treated and untreated front teeth was 2.24% (SD 3.28, P less than 0.01). The majority of the sites showed little or no loss. Maximum loss (35%) was observed in one site only. No association was found between initial bone loss and bone loss during orthodontic treatment. Spaces from 0.1 to 1.8 mm opened up adjacent to the retainer in seven patients. Relapse within the retained segment was associated with failures of the retainer. Of the 19 patients who had been in retention for more than 4 months (mean 16.0, SD 12.1), ten failures were recorded in nine patients. The failure mode was loosening of one or two teeth between wire and composite.
Clinical experiments were performed to investigate the effect of fluoride on carious lesion development and on lesions established during fixed orthodontic therapy. All presently available fluoride agents are developed from the concept of fluoridating the enamel in the form of fluorhydroxyapatite. Recent research has indicated, however, that calcium fluoride formation may be a major aspect of the mechanism of the cariostatic effect of topical fluoride. Therefore a fluoride solution with very low pH (1.9) that induced large amounts of calcium fluoride also was tested on lesion development underneath orthodontic bands. Daily fluoride mouth rinsing with a 0.2% solution sodium fluoride (NaF) retarded lesion development significantly, whereas the fluoride solution with low pH inhibited lesion formation completely. Fluoride applied as a mouth rinse to plaque-covered lesions underneath orthodontic bands retarded lesion progression. The remineralizing capacity of saliva was found to be rapid in the absence of any fluoride. Although white spot lesions may remineralize and even disappear, most of the emphasis should be directed against prevention of carious lesion development during treatment with fixed orthodontic appliances.