Orthodontic treatment with fixed appliances in the General Dental Service in Scotland

Orthodontic treatment quality evaluated by partially automated digital IOTN and PAR index determination: a retrospective multicentre study

Background

Orthodontic therapy aims to treat misaligned teeth and jaws to improve dental occlusion as well as the function and aesthetics of the masticatory system. Continuous data collection to check treatment quality is of great importance for the constant optimization of orthodontic care.

Objective

The aim of this retrospective multicentre cohort study was to systematically determine the outcome and quality of orthodontic treatment by applying the internationally established Index of Orthodontic Treatment Need (IOTN) and Peer Assessment Rating (PAR) index in multiple clinical settings for a representative number of patient cases.

Materials and methods

A total of 1509 consecutive orthodontic patient cases (treatment completion between January 2018 and December 2020) from three representative orthodontic centres (University clinic, city office, small town office) were analysed in a multicentre study. The pre- and post-treatment casts were scanned, digitally measured, and partially automatically evaluated using the IOTN and PAR indices.

Results

A statistically significant improvement in occlusion was observed for medically necessary treatment of IOTN grades 4 and 5 in 97.30 per cent of the analysed cases and for treatment-requiring grades 2 and 3 in 94.08 per cent of the analysed cases. The average percentage PAR improvement was 76.51 per cent. 72.50 per cent of cases showed improvement of more than 70 per cent. The mean PAR index score was reduced from 28.19 ± 9.49 to 6.22 ± 5.41 points.

Conclusion

The present data demonstrate that orthodontic treatment is efficient in inducing significant improvement of malocclusions in general and has a high success rate with severe dysgnathia.

[Health relevance of malocclusions and their treatment]

Zahn- und Kieferfehlstellungen gehören zu den häufigsten Mundgesundheitsbeeinträchtigungen beim Menschen. Der vorliegende Beitrag gibt eine Übersicht zu deren Ursachen, Häufigkeit und Folgen. Er zeigt die präventiven und kurativen Möglichkeiten kieferorthopädischer Behandlungen auf und gibt Informationen zu deren rechtlichen Rahmenbedingungen in Deutschland. Inanspruchnahme und Qualität der kieferorthopädischen Versorgung werden im internationalen Vergleich dargestellt.

Bei den Ursachen für Zahn- und Kieferfehlstellungen spielen genetische, epigenetische, funktionelle und umweltbedingte Faktoren eine Rolle, die individuell meist nicht eindeutig feststellbar sind. Bisher zeigen nur kleinere Querschnittsstudien, dass bis zu 80 % der Kinder in Deutschland betroffen sind. Essen, Trinken, Kauen, Sprechen und Atmen können beeinträchtigt sein, die Neigung zu Parodontalerkrankungen sowie Überlastungsschäden von Kiefergelenk und Kaumuskulatur sind erhöht. Bei einer Proklination der oberen Schneidezähne steigt die Gefahr von Frontzahntraumata. Fehlstellungen können zudem negative psychosoziale Folgen oder Einschränkungen der Lebensqualität zur Folge haben. Kieferorthopädische Behandlungen leisten in Kooperation mit anderen (zahn-)medizinischen Fachdisziplinen einen wichtigen präventiven bzw. kurativen Beitrag zur Verbesserung der Mundgesundheit, der Allgemeingesundheit und der Lebensqualität.

Die Kieferorthopädie bietet ein erhebliches Potenzial für die Stärkung der zahnärztlichen Prävention im Gesundheitswesen, zumal die gesetzliche Krankenversicherung (GKV) eine breitflächige Versorgung der Bevölkerung mit kieferorthopädischen Leistungen auf international anerkanntem, hohem Niveau ermöglicht. Um die Prävention weiter zu verbessern, wird die Einführung eines kieferorthopädischen Screenings im 7.–8. Lebensjahr als systematische Vorsorge empfohlen.

Quality of orthodontic care-A multicenter cohort study in Germany : Part 1: Evaluation of effectiveness of orthodontic treatments and predictive factors

Aims

Orthodontic care and its effectiveness have increasingly become the focus of political and public attention in the recent past. Therefore, this multicenter cohort study aimed to report about the effectiveness of orthodontic treatments in Germany and to identify potential influencing factors.

Methods

A total of 586 patients from seven German study centers were screened for this cohort study, of which 361 patients were recruited at the end of their orthodontic treatment. Of these, 26 patients had missing study models and/or missing treatment information. Thus, 335 participants were included. The severity of malocclusion was rated using the Peer Assessment Rating (PAR) Index at baseline (T0) retrospectively and—prospectively—after the retention period (T1). Practitioner-, treatment- and patient-related information were analyzed in order to detect potential predictive factors for treatment effectiveness.

Results

Study participants (202 female and 133 male) were on average 14.8 (standard deviation [SD] ± 6.1) years old at start of active treatment. Average PAR score at T0 was 25.96 (SD ± 10.75) and mean posttreatment PAR score was 3.67 (SD ± 2.98) at T1. An average decrease of total PAR score by 22.30 points (SD ± 10.73) or 83.54% (SD ± 14.58; p < 0.001) was detected. Furthermore, 164 treatments (49.1%) were categorized as ‘greatly improved’ but only 3 treatments (0.9%) as ‘worse or no different’; 81.5% of all cases finished with a high-quality treatment outcome (≤5 PAR points at T1). Logistic regression analyses detected staff experience as a significant predictive factor for high-quality results (odds ratio 1.27, p = 0.001, 95% confidence interval 1.11–1.46).

Conclusion

The improvement rate among this selected German cohort indicated an overall very good standard of orthodontic treatment. Staff experience proved to be a predictive factor for high-quality results.

Factors influencing orthodontic treatment outcome in South East Wales and implications for service commissioning

AIM

To determine factors that may influence the outcome of orthodontic treatment undertaken in General Dental Services/Personal Dental Services in South East Wales.

DESIGN AND SETTING

A retrospective study of a requested 20 consecutively treated cases (for the year 2014-2015) provided by 26 performers in South East Wales.

METHOD

Performer and patient information was obtained by use of a questionnaire and FP17OW forms, respectively. A calibrated investigator recorded the Index of Orthodontic Treatment Need (IOTN), Peer Assessment Rating (PAR) and the Index of Complexity, Outcome and Need (ICON) on start- and end-study models for each case. Descriptive and regression analyses were undertaken to identify any predictive factors of a good treatment outcome.

RESULTS

Two respondents completed < 20 cases, so all of their cases were assessed. A total of 495 cases were assessed. The overall achieved mean end-PAR score of 5 is collectively a good occlusal outcome. Predictive factors of a good quality of occlusal outcome (end-PAR score being ⩽ 5) were: dual arch treatment; use of functional with fixed appliances; treatment undertaken in non-corporate practices; and treatment undertaken by registered specialists (P < 0.001). Predictive factors for occlusal improvement (change in PAR score) were: IOTN aesthetic component (AC); IOTN dental health component (DHC) (1-3 or 4-5); and number of arches treated and malocclusion type (P < 0.001).

CONCLUSIONS

Dual arch fixed appliances undertaken by orthodontic specialists in non-corporate environments produced the highest quality orthodontic outcomes. Those who have the highest need for treatment according to IOTN DHC and AC benefit most in terms of improvement achieved in PAR score.

A randomized clinical trial of the effectiveness of 0.018-inch and 0.022-inch slot orthodontic bracket systems: part 2-quality of treatment

OBJECTIVE

To compare the quality of orthodontic treatment between 0.018-inch and 0.022-inch slot bracket systems.

SUBJECTS AND METHODS

Eligible participants aged 12 years or over were allocated to the 0.018-inch or 0.022-inch slot MBT appliance (3M-Unitek, Monrovia, California, USA) using block randomization in groups of 10. Outcome measures included: 1. ABO cast-radiograph evaluation (CR-EVAL), 2. peer assessment rating (PAR) scores, 3. incisor inclination, and 4. patient perception using the Index of Orthodontic Treatment Need aesthetic component (IOTN AC) and three validated questionnaires before, during and after treatment. Parametric tests [independent samples t-test and two-way analysis of variance (ANOVA)] and non-parametric tests (chi-square with Fisher's exact tests and Mann-Whitney U-test) assessed differences between groups (P < 0.05).

RESULTS

Of the 187 participants randomized (1:1 ratio), 34 withdrew or were excluded (protocol deviations or poor cooperation). There were 77 patients in the 0.018-inch slot group and 76 patients in the 0.022-inch slot group (overall mean age: 19.1 years). Baseline characteristics were similar between groups (P > 0.05). The mean total ABO CR-EVAL scores were 34.7 and 34.5; mean percentage PAR score reduction 74.1 per cent and 77.1 per cent; mean change for maxillary incisor inclination 2.9 degrees and 1.6 degrees and for mandibular incisor inclination 2.7 degrees and 1.4 degrees for the 0.018-inch and 0.022-inch groups, respectively. Improvement in patient perception of aesthetics after treatment was statistically significant for both groups (P < 0.05). However, there were no statistically significant differences between the two treatment groups for ABO CR-EVAL, percentage PAR score reduction, incisor inclination, and patient perception of treatment (P > 0.05). No adverse events were observed during treatment.

LIMITATIONS

It was impossible to blind clinicians or patients to allocation and oral hygiene and periodontal outcomes were not assessed.

CONCLUSIONS

There were no statistically or clinically significant differences in the quality of occlusal outcomes, incisor inclination and patient perception of treatment between 0.018-inch and 0.022-inch slot bracket systems.

REGISTRATION

The trial was registered with ClinicalTrials.gov on 5 March 2014, registration number: NCT02080338.

PROTOCOL

The protocol was published at DOI: 10.1186/1745-6215-15-389.

The Scottish Orthodontic Peer Review project: the outcome of treatment and standard of record keeping by orthodontic specialist practitioners in Scotland

OBJECTIVES

Assess occlusal outcomes of treatment and clinical record keeping in specialist practice in Scotland.

DESIGN

A retrospective cohort study.

SETTING

Specialist practices in Scotland.

PARTICIPANTS

Specialist orthodontists in Scotland.

METHODS

Every specialist practitioner in Scotland (51) was invited to take part in the peer review project with 38 (76%) enrolled. Scotland was split into four geographical areas, and each practitioner matched with a colleague from the same area. Practitioners took one day to visit their colleague and score 30 consecutively treated NHS cases using the Peer Assessment Rating (PAR) index. They also assessed the quality of the records taken. Practitioners then swapped roles and assessed their partner's occlusal outcomes and records.

RESULTS

The mean pretreatment PAR score was 28.6 (SD 3.5). Mean posttreatment PAR score was 3.5 (SD 1.2). Mean reduction in PAR score was 25.1 (SD 3.8). Mean percentage PAR score reduction was 87.7% (SD 3.7%). Overall record keeping scores were written records 100%, study models 99.5%, Orthopantomogram radiograph 99.2%, photographs 86.3%, medical history 75% and consent 40.8%.

CONCLUSIONS

Occlusal outcomes achieved by specialist practitioners in Scotland were of a high standard. They maintained a good standard of clinical record collection in most areas examined.

An exploratory study of the cost-effectiveness of orthodontic care in seven European countries

This study investigated the orthodontic treatment of 429 consecutive patients [172 male (40.1 per cent) and 257 female (59.9 per cent)] carried out by 10 orthodontic specialist practitioners in seven European countries [two in the Czech Republic (A and B), two in Germany (A and B), Italy, Latvia, Lithuania, and Netherlands, and two in Slovenia (A and B)]. The median age of the patients at the start of treatment was 13.0 years (minimum 7.3 years maximum 50.3 years). The patients had a range of malocclusions and the majority (97 per cent) were treated with upper and lower fixed appliances. Real exchange rates were calculated using purchasing power parity (PPP) indicators to allow cross-border comparisons of costs. The Index of Complexity, Outcome and Need (ICON) was used to measure the effectiveness of treatment and cost per ICON point reduction to compare cost-effectiveness of orthodontic treatment between practitioners in different European countries. The median cost per ICON point reduction for all the cases treated was 57.69 euro. The median cost per ICON point reduction varied greatly between practitioners from 21.70 euro (Lithuania) to 116.62 euro (Slovenia A). Analysis of variance and Tukey post hoc tests showed the differences in cost-effectiveness between the practitioners to be statistically significant (P<0.001). The cost per ICON point reduction is a simple and effective method of comparing cost-effectiveness between orthodontic practitioners in different countries.

The seven-year outcome of an early orthodontic treatment strategy

The benefits of early orthodontic treatment are continuously discussed, but studies are few. We examined whether definite need for orthodontic treatment could be eliminated in public health care by systematically focusing on early intervention. One age cohort living in a rural Finnish municipality (N = 85) was regularly followed from ages 8 to 15 years, and persons with malocclusions were treated according to a pre-planned protocol. Treatment need was assessed according to the Dental Health Component (DHC) of the Index of Orthodontic Treatment Need, and treatment outcome by the Peer Assessment Rating Index (PAR). Fifty-two percent of the cohort received treatment, and definite treatment need decreased from 33% to 9%. In the treated group, the mean PAR score reduction was 63%, and 51% showed more than 70% improvement. The results suggest that an early treatment strategy may considerably reduce the need for orthodontic treatment in public health care with limited specialist resources.

Misuses of correlation and regression analyses in orthodontic research: The problem of mathematical coupling

INTRODUCTION

The aim of this article was to encourage good practice in the statistical analyses of orthodontic research data. Our objective was to highlight the statistical problems caused by mathematical coupling (MC) in correlation and regression analyses. These statistical problems are among the most common pitfalls in orthodontic research when exploring associations among clinical variables. This article will show why these problems arise and how they can be avoided and overcome.

METHODS

Four orthodontic journals were electronically and manually searched for articles that used correlation and regression analyses. Studies that seemed to suffer from MC in their statistical analyses were identified and carefully examined.

RESULTS

Several examples from our search illustrate that MC in correlation and regression analyses can potentially cause misleading results. More appropriate statistical methods are available and should be used to eliminate confusing results and improve any subsequent interpretations. Because many clinical and radiographic variables used in orthodontic research are correlated due to direct or indirect MC, interpretation of studies in the literature needs to be cautious.

CONCLUSIONS

Correlation and regression analyses are useful tools in orthodontic research when their assumptions and limitations are recognized. However, greater care is required in formulating research questions and experimental designs. It is prudent to seek statistical advice when orthodontic research involves complex data analyses.

The problem of analysing the relationship between change and initial value in oral health research

The relationship between initial disease status and subsequent change following treatment has attracted great interest in dental research. However, medical statisticians have repeatedly warned against correlating/regressing change with baseline because of two methodological concerns known as mathematical coupling and regression to the mean. In general, mathematical coupling occurs when one variable directly or indirectly contains the whole or part of another, and the two variables are then analyzed by using correlation or regression. Consequently, the statistical procedure of testing the null hypothesis - that the coefficient of correlation or the slope of regression is zero - may become inappropriate. Regression to the mean occurs with any variable that fluctuates within an individual or a population, either owing to measurement error and/or to physiological variation. The aim of this article was to clarify the conceptual confusion around mathematical coupling and regression to the mean within the statistical literature, and to correct a popular misconception about the correct analysis of the relationship between change and initial value. As examples that use inappropriate methods to analyze the relationship between change and baseline are still found in leading dental journals, this article seeks to help oral health researchers understand these problems and explain how to overcome them.

The relationship between baseline value and its change: problems in categorization and the proposal of a new method

Oral health researchers have shown great interest in the relationship between the initial status of diseases and subsequent changes following treatment. Two main approaches have been adopted to provide evidence of a positive association between baseline values and their changes following treatment. One approach is to use correlation or regression to test the relationship between baseline measurements and subsequent change (correlation/regression approach). The second approach is to categorize the lesions into subgroups, according to threshold values, and subsequently compare the treatment effects across the two (or more) subgroups (categorization approach). However, the correlation/regression approach suffers a methodological weakness known as mathematical coupling. Consequently, the statistical procedure of testing the null hypothesis becomes inappropriate. Categorization seems to avoid the problem of mathematical coupling, although it still suffers regression to the mean. We show, first, how the appropriate null hypothesis may be established to analyze the relationship between baseline values and change in the correlation approach and, second, we use computer simulations to investigate the impact of regression to the mean on the significance testing of the differences in the average treatment effects (or average baseline values) in the categorization approach. Data available from previous literature are reanalyzed by testing the appropriate null hypotheses and the results are compared to those from testing the usual (incorrect) null hypothesis. The results indicate that both the correlation and categorization approaches can give rise to misleading conclusions and that more appropriate methods, such as Oldham's method and our new approach of deriving the correct null hypothesis, should be adopted.