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In a prospective plaque regrowth study focusing on oral hygiene during fixed appliance therapy 12 adolescent patients (mean age 14.1 +/- 1.5 years) were evaluated twice over 2-day test periods. In the randomized, double-blind study the influence of a 0.2% chlorhexidine (CHX) mouthrinse (Corsodyl) and a commercially available dentifrice supplementing fluoride (Odol-med-3) were compared intra- and interindividually in a crossover design with regard to plaque and gingivitis. Before starting the first test phase there was a 14-day preliminary phase for upgrading the oral hygiene. Between the 2 test phases was a 5-day "washout". On the last day of the second test phase the patients were asked to fill in a questionnaire concerning their experiences during the study. The 0.2% Corsodyl reduced the plaque index scores significantly (p < 0.001). The gingival index revealed a similar reduction (2nd day of test: p = 0.03). Until the 5th day of washout a clear-cut carryover effect of the chlorhexidine rinse on the gingival index was observed. Both the lower mean values of the 2 clinical parameters at the beginning of the test phases as compared with those at the beginning of the preliminary phase and the evaluation of the questionnaires indicated a possible Hawthorne effect. 0.2% Corsodyl may be employed as an adjunct to other preventive measures such as professional care and patient-oriented instruction on an intermittent basis in order to reduce the plaque-induced iatrogenic side effects and to enhance the efficacy of oral hygiene measures in connection with orthodontic therapy with fixed appliances.

Aim: To elucidate factors that influence choice of appliance type in General Dental Service (GDS) orthodontics in England and Wales., Method: Records were obtained for 1527 cases, representing a systematic 2 per cent sample of GDS cases completed during 1990-91. Evaluation involved Discriminant Analysis to find the most influential factors in appliance choice. Factors considered included patient and practitioner characteristics, and features of the malocclusion as assessed by Occlusal Indices., Results: Full data were available for 1217 cases. 24 per cent of treatments included use of dual- and 26 per cent single-arch fixed appliances. Appliance choice was predictable in 55 per cent of cases. Older patients, orthodontically qualified practitioners, high Peer Assessment Rating score at start, permanent dentition, lower grades of the Dental Health Component of the Index of Orthodontic Treatment Need at start, and practitioners with high gross earnings from orthodontics, all tended to be associated with more frequent use of fixed appliances., Conclusions: Possession of a diploma or membership in orthodontics was associated with more frequent use of both dual- and single-arch fixed appliances. Better appliance selection, and thus more effective treatments in the GDS, may result from a greater availability of practitioners with formal postgraduate training in orthodontics.

The aim of this study was to quantify the stress induced in the periodontal ligaments by the orthodontic appliances. A finite element model of an orthodontic system, applied on a lower premolar, was developed in different loading conditions. The maximum stress values depend on the location, direction and the magnitude of force application.

The present study is divided into 2 parts: The first explains the concept of stimulating plate therapy at the Muenster Clinic and the second presents a longitudinal study of mouth and tongue posture in trisomy 21 children treated with this concept. 47 children underwent a pre-treatment examination (Rec1), and 38 attended a first follow-up examination (Rec2) after an average of 4 months of stimulating plate treatment. The second follow-up examination (Rec3) was on average 53 months after the end of treatment and covered 18 patients. Data acquisition was based on standardized parent questionnaires and standardized clinical examination records. Rec2 showed in part a highly significant improvement in orofacial appearance. These results were confirmed by the parent interview, according to which the mouth and tongue posture improved in 76.3% of the children during the time they were wearing the plate. Even when the plate was not in place, the result remained stable in 65.8% of the patients. Up to Rec3, further improvement was recorded in some results. The symptoms: "mouth mostly wide open" and "tongue mostly protruding way over lips" were reduced. The number of children whose tongue was "mostly in the oral cavity" increased correspondingly. At Rec3, the parents also rated the mouth posture in 88.9% and the tongue posture in 77.7% of the children as stable or further improved.

The aim of this in vitro study was to investigate different light-cured and chemically cured resin-modified glass ionomer cements used for the cementation of orthodontic bands and to analyze various factors influencing the adhesive strength between enamel, cement and stainless steel. Four resin-modified glass ionomers (Fuji Ortho LC/GC, Fuji Duet/GC, Unitek Multi-Cure Glass Ionomer Orthodontic Band Cement/3M Unitek, Vitremer/3M) and 1 compomer (Band-Lok/Reliance) were examined. Flattened and polished bovine teeth embedded in polyurethane resin were used as enamel specimens. Before cementation, 50% of the specimens were moistened with the aerosol of an inhalation device, while the rest were dried with compressed air. Stainless steel cylinders (CrNi 18 10) were perpendicularly bonded onto the polished enamel using a custom-made cementation device and immediately topped with a pressure of 0.25 MPa. The cement was isolated with either Ketac Glaze/ESPE, Fuji Coat/GC, Cacao Butter/GC, Dryfoil/Jalenko or Final Varnish/VOCO, or was left uncoated. Eight minutes after the beginning of mixing, either the surplus cement was removed with a scalpel or surplus removal was simulated with ultrasound. After 24 hours storage in a water bath at 37 degrees C and 1,000 thermocycles the shear bond strength was determined. Significant differences with respect to the shear bond strength were found among the following cements, ranking from highest to lowest: Fuji Duet, Unitek cement > Fuji Ortho LC > Vitremer > Band-Lok. The application of a barrier coating significantly increased the shear bond strength of all cements except Fuji Ortho LC. The light-cured resin Ketac Glaze proved to be the most effective barrier coating. A dry enamel surface increased the bond strength of all investigated cements except Unitek cement. The use of ultrasound led to no significant reduction in shear bond strength in comparison with surplus removal with a scalpel.

One important aspect in evaluating the outcome and quality of orthodontic treatment is the patient's own assessment. The objective of this study was to evaluate the course and outcome of orthodontic treatment in adults from the patient's vs the operator's point of view. In a previous study, the orthodontic treatment of 88 adults was evaluated using the IOTN and PAR Index before and after treatment. Fifty-nine patients answered treatment questionnaires on 1. the reason for seeking treatment, 2. dentofacial aesthetics, 3. treatment outcome, 4. course of treatment, 5. attitude, 6. social well-being. Depending on the original treatment goal, the patient population was divided into an Ideal Group and a Compromise Group. In 75% of the patients, dissatisfaction with dental aesthetics was the prime motive for seeking treatment; correlations with PAR parameters (overjet and maxillary anterior teeth) were weak. In general, a high degree of patient satisfaction with orthodontic treatment was registered. As regards satisfaction with post-treatment dental aesthetics there were no significant differences between the groups. Comparison of professional assessment with the subjective rating by patients revealed discrepancies in that the patients' rating of outcome tended to be more positive. The differentiation between ideal and compromise treatment goals proved useful. In the Compromise Group, a high level of patient satisfaction was attained with a shorter treatment duration and lower appliance involvement. 92% considered their major pre-treatment need to have been met, and 95% would have had the treatment performed again.

The purpose of this study was to examine diagnosis and treatment planning categorizations used by experienced orthodontists. Thirty-nine clinicians were asked to evaluate six test cases and formulate a diagnosis and treatment plan for each. The information provided was categorized using a problem-oriented classification. The results indicate little agreement exists in diagnostic subcategories, such as molar relationship, degree of crowding, or the nature of skeletal discrepancies. There was also little agreement regarding some treatment strategies, such as extraction of teeth, the use of orthopedic appliances, or the use of surgery. A need exists for better definitions of diagnostic criteria and appropriate treatment options.

The aim of this study was to measure in vivo the forces and moments acting therapeutically on the individual tooth in connection with the multiband technique. Securing and evaluating the planned in vivo measurements involves analysing the measuring accuracy of the system as a whole by means of corresponding in vitro investigations. Errors in determining the therapeutically effective force system may result from the electrical measurement of the mechanical quantities by the sensor system and from the fixing of the archwire in therapeutic position. The precision of this fixing is influenced by displacements induced by elasticities and mechanical tensions in the measuring system. Calibration test series have shown the sensor system to have a margin of error of less than 2%. The displacements influencing precision fixing of the archwire were determined by means of a laser position measuring system. For a maximum orthodontic force of 1.5 N, they are 0.06 mm in the least favourable case. The resulting measuring accuracy was determined analytically or graphically, depending on the key parameters. Successful in vivo studies of the therapeutically applied force systems are to be expected on the basis of these results.

The purpose of this paper was to compare radiographically the prevalence and degree of apical root resorption after treatment with a fully programmed edgewise appliance (FPA) and a partly programmed edgewise appliance (PPA) in a randomized multipractice clinical trial. Two groups of patients with Class II malocclusions were treated orthodontically. The type of treatment was randomly assigned by a computer program. During fixed appliance therapy, one group was treated according to the precepts of the straight wire concept (FPA; n = 32) while the other was treated with conventional full edgewise mechanics (PPA; n = 29). Treatment times were recorded. Radiographs of the maxillary incisors were made before and after active treatment with fixed appliances using the bisecting angle technique. To correct for different projecting angles the pairs of radiographs were digitally reconstructed. The prevalence and degree of root resorption were assessed. The mean treatment time was 1.8 years and 1.6 years for treatment with FPA and PPA, respectively. The mean amount of loss of tooth length was 8.2% for the patients treated with FPA and 7.5% for the patients treated with PPA. No statistically significant differences could be assessed between both groups at the end of active treatment. The mean prevalence of apical root resorption was 75% for the patients treated with FPA and 55% for the patients treated with PPA. Statistical evaluation showed no significant differences. We concluded that the prevalence and degree of root resorption is independent of the appliances as used in this study.

In the correction of Class II malocclusions, derotation of the maxillary first molars is required to obtain an idealized Class I relation. Because of its trapezoidal shape, the maxillary first molar is believed to provide an arch length gain attendant to its derotation, which may subsequently be used to resolve deficiencies mesial to it. Two commonly used mechanisms for maxillary first molar derotation and its associated centers of rotation were studied. A transpalatal arch, when accompanied by distal force equivalent at the level of the maxillary first molar center of resistance, can provide a center of rotation approximating the lingual attachment. This produces an arch length gain of 2.1 mm anterior to the molar, while simultaneously impinging on the maxillary second molar space 1.2 mm (per side). In reality, this may be a transference of a problem in one area of the dental arch to another. The 2 x 4 and 2 x 6 arch wires provide for various centers of rotation along an axis from the molar center of resistance--as projected to the occlusal surface--to the region of the maxillary first molar distal marginal ridge. These centers of rotation do not provide any meaningful alteration in arch length. These arch wires are useful, however, for maxillary first molar derotation necessary to achieve an idealized Class I molar occlusion. It is evident that the arch length gain related to derotation of the maxillary first molars, irrespective of the center of rotation, is insufficient to achieve Class I premolar intercuspation. Additional factors as growth, surgical intervention, or extractions are needed to achieve Class I premolar articulation.

The finite element method of analysis (FEM) was used to analyze theoretically the effects of a transpalatal arch (TPA) on periodontal stresses of molars that were subjected to typical retraction forces. The purposes of this investigation were (1) to construct an appropriate finite element model, (2) to subject the model to orthodontic forces and determine resultant stress patterns and displacements with and without the presence of a TPA, and (3) to note any differences in stress patterns and displacements between models with and without a TPA. Because anchorage is stress-dependent, a TPA must be able to modify periodontal stresses as a prerequisite for increasing orthodontic anchorage. A finite element model, consisting of two maxillary first molars, their associated periodontal ligaments and alveolar bone segments, and a TPA, was constructed. The model was subjected to simulated orthodontic forces (2 N per molar) with and without the presence of the TPA. Resultant stress patterns at the root surface, periodontal ligament, and alveolar bone, as well as displacements with and without a TPA, were calculated. Analysis of the results revealed minute differences of less than 1% of the stress range in stress values with respect to the presence of a TPA. Modification of bone properties to allow for increased displacement levels confirmed the ability of the TPA to control molar rotations; however, no effect on tipping was noted. Results suggested that the presence of a TPA has no effect on molar tipping, decreases molar rotations, and affects periodontal stress magnitudes by less than 1%. The final results suggest an inability of the TPA to modify orthodontic anchorage through modification of periodontal stresses.

The need for orthodontic treatment in Kenya was previously not been investigated. This study was undertaken to assess the need for orthodontic treatment in 13- to 15-year-old children in Nairobi. The objective need was assessed in 919 children by using the Norwegian treatment need index, and the subjective need was assessed in 739 children by using a structured questionnaire. Objective treatment need was recorded in 29% and subjective need in 33% of the children. Less than 1% were allocated the 'very great need' category. Relatively more girls than boys were dissatisfied with the appearance of their teeth, and a significantly higher number of girls (P < 0.001) said they would like to have their teeth straightened. The children's perceived need for treatment correlated significantly with the treatment need index. Fixed appliances were found necessary for correcting malocclusion in 23% of the children and removable appliances in 6%. Future studies in Kenya should be directed at determining the societal perception of malocclusion, upon which treatment standards may be based.

A survey of 468 Grade Seven students and 437 parents in the North Brisbane region was undertaken to determine perceptions of orthodontic appliances. Based on responses to statements on the survey, a Perception Score was created for both students and parents in relation to both fixed and removable appliances. Both students and parents had more negative perceptions of fixed appliances than of removable appliances. Fixed appliances were perceived to attract more teasing, to cause more problems in the maintenance of oral hygiene and to be more painful than a removable plate. Respondents also felt that children would have to be more careful about what they eat when wearing fixed appliances. Approximately forty per cent of students and parents did not know whether teeth could be damaged by orthodontic appliances nor whether the appliances would cause discomfort. Parents had significantly more negative perceptions of both types of orthodontic appliances than did the students. The Perceptions scores were not significantly influenced by whether the students attended a private or public sector dentist, the frequency of dental visits, any history of orthodontic treatment, nor by the parents' level of education and their occupations. A forewarning about experiences of orthodontic appliances would better prepare patients and assist operators in providing the community with a more comprehensive orthodontic service.

The aim of the present study was to assess the efficiency of a 1% chlorhexidine-containing varnish (Cervitec, Vivadent, Liechtenstein) on the levels of Streptococcus mutans in saliva of patients with fixed orthodontic appliances using the Dentocult-SM (Vivadent, Liechtenstein) technique for the microbiological investigation. Eighty subjects participated in the study and, divided randomly into two equal groups in which one group was treated with the placebo varnish (Vivadent, Liechtenstein) for negative controls. Streptococcus mutans in saliva of the subject was sampled and enumerated by using the Dentocult-SM dip-slide technique for periods of one, two four and twelve weeks after a single varnish application. The results were evaluated statistically. After the chlorhexidine containing varnish treatment the levels of Streptococcus mutans in saliva were significantly reduced after one week (p < 0.01) and continued reduction for one month (p < 0.05). After twelve weeks Streptococcus mutans levels in saliva were given a relative increase. No significant suppression was found in the placebo group (p > 0.05). The results suggested that Cervitec varnish reduces salivary Streptococcus mutans levels and that the application should be repeated every 3 months to get antibacterial effect.

Levels of mutans streptococci in plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) (Ketac-Cem) and a resin-based composite (CR) (Concise) were investigated, using the split mouth technique in 11 patients who, before treatment, had more than 10(5) CFU of these microorganisms. After full-term orthodontic treatment (mean 9.5 months), the percentage of mutans streptococci of total CFU count in plaque was lower adjacent to GIC-retained brackets (mean 3.9) than adjacent to CR-retained brackets (6.7), but the difference was not statistically significant. Two subjects harbored S. sobrinus. These subjects were the only ones who developed incipient caries during the orthodontic treatment. Incipient lesion formation occurred only adjacent to CR-retained brackets. This suggests that in patients who have relatively high salivary levels of mutans streptococci before treatment and especially in those who harbor S. sobrinus, the use of GIC for bonding may prevent incipient caries formation during orthodontic treatment.

This study investigated the effect of the palatal crib appliance used in the correction of open bite malocclusions secondary to fingersucking. Twelve experimental and 12 control subjects were studied for an average of 3.9 months. The sample consisted of patients who were both growing and not growing. Study models taken before and after the study period were analyzed for changes in the following dimensions: overbite, overjet, arch perimeter, arch length, and incisor angulation. Data were analyzed with student t-tests to determine statistical significance. Partial or complete closure of the open bite was achieved averaging 3.7 mm +/- 1.9 mm during the observation period in the experimental group treated with palatal crib therapy. In contrast, the control group displayed a mean bite opening of 0.4 mm +/- 0.8. These values were statistically significant at the P < 0.001 level. Open bite decreased as incisor angulation (P < 0.02), arch length (P < 0.05), and arch perimeter (P < 0.01) decreased. Overjet changes were minimal and statistically insignificant.

Orthodontic services for Finnish children and adolescents up to the age of 18 in 1992 were monitored by a questionnaire sent to all municipal health centres responsible for children's dental care in Finland, and 96% responded. All health centres provided some orthodontic treatment, but the percentage of 0 18-year-old children receiving treatment ranged from 1% to 19%. One-quarter of all dental visits of the 0 18-year-olds were in connection with orthodontics. The timing of treatment was early, the average age for starting was 9.5 years. In statistical analyses, the number of children receiving treatment was associated with the timing of treatment. At the age of 7, the most frequently used appliances were quad helix, removable appliance and orthopaedic headgear and, at the age of 13, fixed appliance and activator. Most treatments were provided by nonspecialists. The specialist expertise needed was usually purchased from an outside orthodontist by means of consultation contracts. Every fifth health centre, usually the largest, had employed one or more specialist orthodontists. The regional distribution of orthodontists was uneven, emphasizing regional variation in the delivery of orthodontic services.

A sample of 172 orthodontic patients treated by 10 general dental practitioners in their practices was assessed in terms of treatment need and standard of treatment provided. The practitioners had been clinical assistants, for a minimum of 2 years, at a District General Hospital before starting any of the cases. Prior to treatment 70% of the cases had a 'clear need' for treatment on dental health grounds and 73% of the cases had a 'moderate' or 'great need' for treatment on aesthetic grounds. Using the Peer Assessment Rating nomogram to assess the treatment standard, 83% of patients could be classed as 'improved' or 'greatly improved' with treatment but 17% were 'worse or no different'. The standard of treatment produced by fixed appliances was found to be superior to that produced by removable appliances alone. When removable appliances were used the best results were obtained when consultant advice was given. The results for the clinical assistant sample are compared with the results for the GDS sample published in 1993. Ways of further improving the treatment standards produced by the general dental practitioners are considered.

An understanding of the determinants of the provision of fixed orthodontic treatment would be beneficial in the planning of any system aimed at rationalising supply. The aim of this longitudinal study was to determine those factors which were predictive of the provision of fixed orthodontic treatment in adolescents. Baseline data, at age 13 years, on oral health, the history of orthodontic consultation and interceptive orthodontic care, a dental appearance score (DAI), socio-demographic characteristics and self and parental perceptions of both dental appearance and need for fixed orthodontic treatment were obtained from 2793 adolescents under the care of the South Australian School Dental Service who had not undergone fixed orthodontic treatment. Data on the orthodontic care provided to these adolescents in the ensuing 2 years were collected. At the end of the 24-month period 433 adolescents (15.5%) had undergone fixed orthodontic treatment. Significant bivariate associations were found between the provision of fixed orthodontic treatment and the DAI score, sex of the adolescent, familial history of fixed orthodontic treatment, income, private insurance, orthodontic consultation and interceptive orthodontic care before the age of 13 years and self and parental perceptions of both dental appearance and the need for fixed orthodontic treatment. Logistic regression was used to produce a predictive model of fixed orthodontic treatment. The model explained 30.2% of the variance, with a specificity of 0.94, a sensitivity of 0.49 and a hit rate of 0.84%. Odds ratios greater than one were found for the DAI score, private insurance, females, self and parental perception of need, higher incomes and orthodontic consultation and interceptive orthodontic care before the age of 13 years.

Although various methods have been used to evaluate orthodontic treatment outcome, the PAR index (Peer Assessment Rating) was recently developed for the purpose of assessing treatment standards. The purpose of this investigation was to evaluate the treatment standard of 52 consecutively treated cases during orthodontic postgraduate training (1991-1993). The pre- and post-treatment study models were collected and analysed using the PAR index. The mean age at start of treatment and the mean treatment duration was 13.6 (+/- 3.6) years and 15.9 (+/- 4.5) months respectively. Dual-arch fixed appliance was the predominant form of treatment employed. A high treatment standard was achieved as indicated by the mean PAR score reduction of 82.6 per cent. Most of the cases (92.3%) showed varying degree of improvement. Of the 4 (7.7%) cases classified as "worse or no difference", three were treated with removable appliances. With the exception of buccal occlusions, treatment showed strong improvement on individual PAR components. The shortcomings of the method of assessment are also discussed.

Based on the favorable results achieved by the application of pseudoelastic T loops in the course of canine retraction, this study investigates their application to the retraction of maxillary incisors. A modified Burstone T loop was made of a pseudoelastic orthodontic nickel titanium wire and then subjected to experimental testing. The results obtained were compared with extensive numerical studies. The results of the tests showed that forces and moments generated by the T loop are suitable for the retraction of upper incisors. The clinical application of the pseudoelastic spring was performed using an individualized retraction arch enclosing the whole front segment. Whereas during canine retraction the experimental and clinical results corresponded very well, such was not observed during the retraction of upper incisors. This result implies that the location of the center of resistance of the upper incisors has not been completely clarified. It is thus recommended that this matter should be given further study.

A systematic sample of 1010 cases was collected by the Dental Practice Board. The commonest type of treatment involved extraction of the first premolars followed by removable appliances. Treatment duration was on average 1.9 years, one-arch fixed appliances were started in an older age group and two-arch fixed appliance treatment took longer to complete than other appliance types. The best standard of treatment was achieved using upper and lower fixed appliances.

One hundred and fifty-four adolescents, 76 female and 78 male consented to take part in this survey. The two authors examined and assessed them for dental aesthetics, malocclusion related features and TMJ related signs. The patients were also questioned about their opinion of dental aesthetics, their interest in having orthodontic treatment and their TMJ symptoms. Only 63 per cent of the adolescents who were considered suitable for orthodontic treatment expressed an interest in wanting treatment. Twenty-seven per cent of patients had signs and/or symptoms of TMJ disturbance. No association was found between individual malocclusion problems and TMJ signs and symptoms. The authors considered 56.5 per cent of the total group for orthodontic treatment, the majority for aesthetic reasons, and placed them into high, medium and low priority groups. Fixed appliance therapy for both arches was the recommended type of treatment for most patients.

The aim of the present study is to describe the changes in the Holdaway angle during and after treatment with a fixed appliance and to search for any possible differences between non-extraction treatment and extraction treatment. Thirty-five randomly selected Angle Class II. Division I cases with complete records before treatment, at the end of treatment, and at time at least one year out of retention, were collected. The sample was divided into two groups, one consisting of nineteen non-extraction cases and the other group of sixteen extraction cases. All cephalometric radiographs were traced on to acetate film and a computer program developed for cephalometric analysis according to the Bergen Technique was used to evaluate the radiographs. A computer program was used for the statistical evaluation of the data. In conclusion it can be said that no significant differences with regard to the Holdaway angle were found between fixed appliance therapy with or without extraction. A significant influence on the Holdaway angle itemed from the sagittal base relation (ANB) and chin prominence. It seems reasonable to assume that only orthopaedic appliances that influence sagittal base relationship, and especially the lower jaw, can have a profound influence on Holdaway angle.

Out of a sample of 1210 orthodontic patients treated within the General Dental Services in England and Wales, a high proportion showed no improvement. Upper and lower fixed appliances had the greatest influence on the outcome of treatment in terms of aesthetics, dental health need and standards. When treatment was analysed according to the appliance used, there were no statistically significant differences in the standard of treatment undertaken by specialist orthodontists and general dental practitioners. Methods for improving British orthodontic standards are considered.

This retrospective study was carried out to assess the need for orthodontic treatment and the standard of treatment provided by a sample of 17 hospital-based orthodontic departments. A total of 1630 sets of patients records were collected and analysed for orthodontic treatment need and standard of treatment with the Index of Orthodontic Treatment Need and the PAR index, respectively. The data were analysed with a variant of analysis of covariance using linear modelling techniques. In general terms it appeared that the hospital service provided treatment of a high standard, in terms of dento-occlusal change, to a caseload of patients that were in need of treatment. The effectiveness of treatment provision was influenced by the grade of operator, the choice of treatment methods and by the departmental attitudes and aspirations.

This study involved the development of a questionnaire to elicit information about current trends in orthodontic practice compared with trends of 5 years ago. The subjects addressed included the use of fixed appliances, functional appliances, extraction therapy, orthodontics and the temporomandibular joint, current diagnostic aids, and medicolegal implications of orthodontic treatment. The questionnaire was mailed to 1400 orthodontic specialists who were randomly selected from across the United States. There were 814 questionnaires returned, representing a 58.14% response rate. The major results of this survey are as follows: (1) The reported extraction rate has declined from a mean of 37.74% 5 years ago to 29.28% today. (2) TMJ concerns (or medicolegal implications thereof) have had a considerable impact in this decline, with 26.4% of orthodontists being influenced, to some extent, to extract fewer teeth because of this factor. (3) The use of functional appliances has remained somewhat static over the last 5 years, after a period of rapid growth in the 5 years previous to that. (4) The preadjusted edgewise appliance is by far the most popular fixed appliance in use today, being chosen by 72.6% of respondents. Analysis of the overall results lead to the following conclusions: (1) Fixed appliance therapy is the therapy of choice of the overwhelming majority of orthodontists. The use, benefits, and role in orthodontics of functional appliance therapy is considerably less defined. (2) Treatment modalities, notably on the use of extraction and its relationship to the health of the temporomandibular joint, should be determined by research, not by legal fears or unsubstantiated allegation.

This longitudinal study compared the periodontal status of bonded and banded molars in 20 adult and 40 adolescent patients before, during and after treatment with fixed orthodontic appliances. Plaque accumulation (measured by the Plaque Index), gingival inflammation (measured by the Gingival Index and the bleeding tendency), and pocket depth were assessed by one examiner at sites along the mesio-buccal line angle of the maxillary right first molar and the mandibular left first molar. Assessments were made immediately prior to the placement of fixed appliances (pretreatment), at 1, 3, 6, 9, 12 and 18 months after appliances were placed; and 3 months after appliances were removed (posttreatment). Loss of attachment between the pretreatment and posttreatment visits also was determined. At pretreatment, no significant differences were found in gingival inflammation between maxillary and mandibular banded and bonded molars. During treatment, both maxillary and mandibular banded molars showed significantly (p less than 0.05) greater gingival inflammation and plaque accumulation than did bonded molars. Three months after appliance removal, the maxillary molars that had been banded continued to show significantly more gingival inflammation and loss of attachment than did the maxillary molars that had been bonded. When all banded and bonded teeth were grouped by patient age, mean values for plaque accumulation and gingival inflammation in the maxillary molar regions were significantly greater for adolescents than for adults.

An epidemiological investigation involving 765 Glasgow schoolchildren aged nine, twelve, and fifteen years was undertaken to assess the severity of malocclusion, the need for orthodontic treatment, and the proportion of children in each age group who had previously received treatment. An index termed the Malocclusion Severity Index (MSI) was developed to establish objectively the severity of malocclusion in each individual. Fifty sets of orthodontic study models and six orthodontists assessed the reproducibility and validity of the index. Although there was a significant reduction in the proportion of children in need of orthodontic treatment between 9 and 15 years of age, a considerable number were still in need of treatment; crowding of their dentitions being responsible for the majority of the treatment requirement. The MSI was found to be as precise and valid as previously developed occlusal indices, for estimating the treatment needs of sample populations.

A survey has been undertaken on a representative sample of 1210 patients collected from a 5% sampling procedure employed by the Dental Practice Board. Discontinued cases were excluded from the study. It was revealed that the majority of orthodontic treatment was undertaken by practitioners who had in general been qualified for at least 10 years and, in the main, did not possess an orthodontic qualification. The greater proportion of treatment was undertaken using removable appliances, although fixed appliances were used in 43% of prior approval cases and treatments attracted an average fee of 171 pounds (1988 prices). There was a marked variation in the proportion and type of treatment carried out in the various regions within the General Dental Services.

The purpose of this investigation was to assess the number of, and the interrelation between, skeletal and dental components that contribute to Class II relapse after Herbst treatment. A comparison was made between 15 relapse and 14 stable cases at least 5 years after treatment. Lateral cephalograms taken before and immediately after Herbst treatment, as well as 6 months and 5 to 10 years after treatment, were analyzed. The results revealed that relapse in the overjet and sagittal molar relationship resulted mainly from posttreatment maxillary and mandibular dental changes. In particular, the maxillary incisors and molars moved significantly (p less than 0.05) to a more anterior position in the relapse group than in the stable group. The interrelation between maxillary and mandibular posttreatment growth was favorable and did not contribute to the occlusal relapse. It is hypothesized that the main causes of the Class II relapse in patients treated with the Herbst appliance were a persisting lip-tongue dysfunction habit and an unstable cuspal interdigitation after treatment.

The recent introduction of ceramic orthodontic brackets has generated interest among orthodontists. The aim of this investigation was to evaluate the in vitro shear bond strengths to enamel of four ceramic orthodontic brackets and one stainless steel bracket in trials with two separate acid-etching times for enamel. Eighty extracted human central incisors were prepared for bonding to Starfire, Allure, Transcend, Quasar, and stainless steel (in the control group) orthodontic bracket systems. Enamel etching times of 15 seconds and 60 seconds were used. There was a total of 10 groups. After acid etching, one coat of low-viscosity bonding agent was applied and the brackets were bonded to etched enamel with Concise orthodontic bonding resin. The bonded test specimens were stored in distilled water at 37 degrees C for 14 days, after which they were thermocycled for 500 cycles (5 degrees C to 60 degrees C). The bonds were stressed to failure in an Instron machine at a crosshead speed of 0.02 inch per minute. The shear bond strengths were calculated and Weibull analysis was used to obtain a shape factor (the slope of the straight line and a measure of predictability) and the characteristic level (the 63.2% bond strength value of median rank on the strength line) for each group. Predictability and high bond strength, along with other factors, are important in the clinical selection of a bracket system. When either predictability or bond strength was considered independently, several bracket systems, coupled with a particular etch time, had either high predictability or high bond strength. The highest predictability and the highest bond strength were both found with the Allure bracket system.

The distribution of both community orthodontic and dental officer manpower has been reviewed, and both exhibit an unequal regional variation. The amount of orthodontic treatment provided was calculated, and expressed as a treatment rate and percentage of fixed: removable appliances fitted. There was a marked regional variation in the form of appliance utilized, and there was a significant relationship between community orthodontic manpower and the relative use of fixed appliances. However, the treatment rate was not related to the manpower distribution. The data collected, by the Department of Health, on the provision of orthodontic treatment was found to have some limitations in its usefulness for epidemiological purposes.

It has been fifteen years since the Department of Orthodontics started in 1973, and this report concerns mainly the results of clinical observations during these period. The results were as follows: 1) Three thousand four hundred and three patients visited during a fifteen years period and 2,065 (61%) of them received orthodontic treatment. This statistical investigation was performed on 2,065 patients. 2) The numbers of treated patients increased from 1973 to 1983 without 1980 but have almost unchanged with about 180 patients from 1984 to 1987. 3) The male patients were less than the female by the ratio of 1:1.67. As to age, the patients from 6 to 12 years old accounted for 72% of all the treated. 4) Analyzed by dental age categories, patients at the stage of III A and III B comprised 54% of all the treated. 5) Analyzed by month, the patients visited on March, July and August in spring and summer vacations. 6) Most of the patients (92%) lived in Fukuoka Prefecture and 38% of them lived in Sawara-ku, where lay in the south-western part of Fukuoka city. 7) Fifty six per cent of all patients were introduced by doctors and dentists. 8) As to malocclutions, the number of mandibular protrusion was the largest, crowding case was next, and maxillary protrusion was third. The total sum of these three cases accounted for 78% of all the treated. 9) In the initial orthodontic appliances, the use of the multi-brackets appliances was first, the chin cap appliances was second and plate appliances was third. The total sum of these three appliances accounted for about 73%. 10) Analyzing to age and initial orthodontic appliances, plate, chin cap, F. K. O. and I. M. A. appliances were used at the age from 7 to 8. Lingual arch appliances were also used at the age of 8. The multi-brackets appliances increased remarkably during the recent five year period and were used at the age of 10 to 11 and over 20 years.