A comparison of the reliability and validity of 3 occlusal indexes of orthodontic treatment need.

Several occlusal indexes are currently used to ascertain eligibility for orthodontic treatment. A comparison of 3 indexes of orthodontic treatment need was made with the consensus opinion of a panel of 15 experienced orthodontists. Sets of study casts (170) representing the full spectrum of malocclusions were selected. An examiner, calibrated in the Dental Aesthetic Index, the Handicapping Labiolingual Deviation with the California Modification, and the Index of Orthodontic Treatment Need, scored the casts. The panel of orthodontists individually rated the same casts for their degree of orthodontic treatment need. The mean rating of the panel on the need for treatment was used as the gold standard for evaluating the validity of the indexes. Intrarater and interrater reliability was high (kappa > 0.8). Overall accuracy of the indexes, as reflected in area under receiver-operating characteristic curves, was also high: Dental Aesthetic Index, 95%; Handicapping Labiolingual Deviation with the California Modification, 94%; and Index of Orthodontic Treatment Need, 98%. Cutoff points for the indexes that resulted in the closest agreement with the gold standard differed from the published cutoff points for the indexes. The indexes appear to be valid measures of treatment need as perceived by orthodontists. The published cutoff points for the indexes were more conservative in assigning patients for treatment than a panel of orthodontists. However, adjusting the cutoff points moved all 3 indexes into close agreement with the experts.     

An insight into four orthodontic treatment need indices

Occlusal indices have been introduced and used to rank or categorize the occlusion. According to Dr. William Shaw and colleagues (1995), there are five types of occlusal indices, diagnostic, epidemiologic, orthodontic treatment need, orthodontic treatment outcome, and treatment complexity indices. Orthodontic treatment need indices are used to rank the malocclusion. They were devised to minimize the subjectivity associated with the diagnosis, referral and complexity assessment of malocclusion. Some are also multifunctional and used to assess the outcome of orthodontic treatment. The overall aim of the present article is to provide an overview on four commonly used American and European orthodontic treatment need indices, review their modifications, advantages, and limitations. These indices are the Index of Orthodontic Treatment Need (IOTN), the Dental Aesthetic Index (DAI), the Handicapping Labio-Lingual Deviation index (HLD), and the Index of Complexity, Outcome and Need (ICON).     

A useful insight into 2 occlusal indexes: HLD(Md) and HLD(CalMod).

Maryland and California are among the states that have adopted the Handicapping Labiolingual Deviation (HLD) Index to determine eligibility for public funding of orthodontic treatment. As a result of several lawsuits against the state, California has developed and employed a modification of that index, called the HLD(CalMod) index. This study compared and contrasted the effects of analyzing prospective patients with the HLD(Md)-the HLD index as used in Maryland-and the HLD(CalMod) indexes. The specific aims of this study were to observe (1) the correlation between the 2 occlusal indexes in determining patients' eligibility for treatment with public funding, (2) the characteristics of patients eligible according to each index, and (3) the major contributing factors in assigning patients as eligible under each index. Initial study models of 313 patients from the orthodontic clinic at the University of Maryland were scored by both HLD(Md) and HLD(CalMod) indexes. According to the scores, the patients were divided into 2 groups-those with handicapping malocclusions and those without handicapping malocclusions. Scores from each index were analyzed by the Pearson product moment correlation. The Angle classification for each patient was also recorded with the HLD variables. The mean and the percentage of the total score for each variable were calculated. The following conclusions were obtained: (1) Of the 313 patients, 127 (41%) were approved for treatment by the HLD(Md) index, and 110 (35%) were approved for treatment by the HLD (CalMod) index.(2) The correlation between the 2 indexes (R = 0.78) was not very strong, indicating the power of the additional variables introduced in the HLD(CalMod) index. (3) The use of the HLD(CalMod) index directs more public funding toward patients with severe Class II malocclusions than does the HLD(Md) index.     

Assessment of the validity of HLD (CalMod) in identifying orthodontic treatment need

Cooke M, Gerbert B, Gansky S, Miller A, Nelson G, Orellana M. Assessment of the validity of HLD (CalMod) in identifying orthodontic treatment need. Community Dent Oral Epidemiol 2010; 38: 50–57. © 2009 John Wiley & Sons A/S   Abstract – 
Objective:  The purpose of this study was to assess the validity of the Handicapped Labio-Lingual Deviation index with California modifications, HLD (CalMod), in identifying handicapping malocclusions.
Methods:  A set of 153 study casts representing all types of malocclusion was utilized in this study. Models were randomly chosen the UCSF Division of Orthodontics clinic. Treatment need was determined by the HLD (CalMod) index and by a panel of 13 orthodontists, conventionally established as the 'gold standard'. Spearman Rank correlation analysis was used to evaluate the correlation between HLD (CalMod) and the gold standard. The Classification and Regression Tree (CART) modeling was used to determine the HLD (CalMod) cut-off point of orthodontic treatment need according to the gold standard.
Results:  A Spearman Rank correlation Coefficient of 0.71 demonstrated a moderately high correlation between HLD (CalMod) and the gold standard. The CART modeling determined a value of 18.5 as the cut-off point of HLD (CalMod) for orthodontic treatment need, considerably lower than the cut-off point of 26 currently used by Medi-Cal. At a value of 26 points as the cut-off HLD (CalMod) displayed a low sensitivity (25.9%) and high specificity (96.8%).With a cut-off point of 18.5, specificity decreased to 55.6% while sensitivity increased dramatically to 92.9%.
Conclusion:  Our results show that the HLD (CalMod) with a cut-off point of 26 fails to indentify a considerable percentage of handicapping malocclusions. More studies should be done assessing the efficacy of the HLD (CalMod) in identifying handicapping malocclusion.     

Effectiveness of training dental students in two occlusal indices

The purpose of this study was to evaluate the ability of students in a U.S. dental school to learn and apply two indices of orthodontic need: the Index of Orthodontic Treatment Need (IOTN) and the Index of Complexity, Outcome, and Need (ICON). Dental students were randomly selected and separated into three groups: control, IOTN, and ICON. Each evaluated thirty casts that had previously been evaluated by a panel of thirteen orthodontists to develop a gold standard of orthodontic treatment need for these casts. Students re-evaluated the same thirty casts after IOTN and ICON training for their own group, while the control group did not receive any training. Logistic regression of pre- and post-training agreement with the gold standard was calculated for each group to create a clear quadratic relationship. Significant differences were not found between pre- and post-training evaluation for either the IOTN or the ICON groups as compared to the control. However, the IOTN group did show more improvement when compared with the ICON group. This study demonstrates that the use of the IOTN index improved assessment in predoctoral dental students to determine orthodontic treatment need.     

Eligibility for publicly funded orthodontic treatment determined by the handicapping labiolingual deviation index

INTRODUCTION: Access to orthodontic care for Medicaid patients has been limited, in part because of orthodontists' reluctance to treat severe malocclusions for low reimbursements. Limited orthodontic treatment in the mixed dentition (phase 1 treatment) has been proposed to address this issue, because the intent of phase 1 treatment is to improve or prevent severe malocclusions. Orthodontists might be more willing to provide shorter, simpler treatment. The purpose of this study was to determine whether phase 1 treatment would reduce malocclusion severity to the extent that eligibility for subsequent Medicaid-funded treatment was significantly reduced. METHODS: Eligibility was determined by the handicapping labiolingual deviation (HLD) index, which is used by several states for this purpose. Eligibility was also determined with the index of complexity, outcome, and need (ICON). This allowed us to compare these 2 indexes. Pre-phase 1 and post-phase 1 index scores were calculated by using study casts from 193 patients treated at the University of Washington orthodontic clinic and the Odessa Brown Children's Dental Clinic, both in Seattle. RESULTS: Using the HLD index, we found that eligibility for orthodontic treatment decreased by 62% after phase 1 treatment. This change was statistically significant at P < .0001. The ICON found significantly more treatment need before phase 1 (90%) than did the HLD index (35%) (P < .0001). CONCLUSIONS: Early interceptive treatment significantly reduces eligibility for comprehensive Medicaid-funded orthodontic treatment. The HLD index is a useful tool for determining Medicaid eligibility.     

Measuring failure of orthodontic treatment: a comparison of outcome indicators

OBJECTIVE: To compare treatment failure rates on a sample of completed and discontinued orthodontic treatment cases as measured by PAR, IOTN and ICON to determine whether the use of a sole index would suffice. SUBJECTS AND METHOD: All patients completing or discontinuing orthodontic treatment in the hospital orthodontic departments in the Northern Region during two calendar months were identified and pre and post-treatment models were analysed. PAR scores, IOTN (DHC and AC) and ICON were recorded. RESULTS: One-hundred-and-forty-five cases were identified and 15 had incomplete records on the day of analysis. The final sample was therefore 130. The overall treatment discontinuation rate of these 130 patients was 24.6%. The treatment failure rate with respect to occlusal improvement varied from 3.1% when measured by PAR and 10.0% using ICON. With respect to residual need it varied from 0.77 to 20.1% with respect to IOTN depending on the criteria examined. The residual treatment need with respect to ICON was 17.2%. CONCLUSIONS: Different occlusal indices give differing failure rates when used on the same patients with ICON being the most critical index. We felt that ICON was the most valid with respect to identifying treatment failure. Its use would enable international comparison of results.     

Orthodontic treatment need of 9, 12 and 15 year-old children according to the Index of Orthodontic Treatment Need and the Dental Aesthetic Index

Objective: To assess the differences in occlusal features in three cohorts at 9, 12 and 15 years of age, and compare orthodontic treatment need measured by the Dental Aesthetic Index (DAI) and Index of Orthodontic Treatment Need (IOTN). Design: Cross-sectional study. Setting: School of Dentistry, University of Valencia. Subjects: A total of 1086 children: 321 aged 9, 397 aged 12 and 368 aged 15. Methods: Children were examined to measure their orthodontic treatment need according to IOTN and DAI. The main outcome measure was orthodontic treatment need according to the DAI and IOTN indices. Results: Overbite and inter-incisal diastema were the occlusal features that presented significant differences between the three groups, diminishing with age. Treatment need according to the IOTN was 15.4% at 9 years, 20.9% at 12 years and 12.8% at 15 years. Treatment need according to DAI was 44.8% at 9 years, 21.7% at 12 years and 14.1% at 15 years. The diagnostic agreement between the two indices on the treatment need by age group was very low at 9 years (Kappa 0.18) and moderate at 12 and 15 years (Kappa 0.451 and 0.405, respectively). Conclusions: Orthodontic treatment need is greater in the mixed dentition and falls slightly as the child grows. The greatest variation in results between 9 and 15 years were found in relation to the DAI, which is consequently not recommended for use in the mixed dentition.     

Validity of the Index of Complexity, Outcome, and Need (ICON) in determining orthodontic treatment need

Occlusal indices are used to determine eligibility for orthodontic treatment in several publicly funded programs. The Index of Complexity, Outcome, and Need (ICON), based on the perception of 97 orthodontists from 9 countries, has been proposed as a multipurpose occlusal index. The aim of this study was to investigate the validity of the ICON as an index of orthodontic treatment need compared with the perception of need as determined by a panel of US orthodontists. One hundred seventy study casts, representing a full spectrum of malocclusion types and severity, were scored for orthodontic treatment need by an examiner calibrated in the ICON. The results were compared with the decisions of an expert panel of 15 orthodontic specialists from the central Ohio area. The simple kappa statistic (0.81) indicated very high agreement of the index with the decisions of the expert panel. The sensitivity (94%), specificity (85%), positive predictive value (92%), negative predictive value (90%), and overall accuracy of the ICON (91%) also confirmed good agreement with the orthodontic specialists. The panel found that 64% of the casts required orthodontic treatment; the ICON scores indicated that 65% of the cases needed treatment. There was agreement between the expert panel and the index in 155 of the 170 cases. These results support the use of the ICON as a validated index of orthodontic treatment need.     

Evaluation of the peer assessment rating (PAR) index as an index of orthodontic treatment need.

The need for orthodontic treatment has an objective component based on occlusal traits and a subjective component based on the esthetic impact of the occlusion. An occlusal index that measures the objective deviation from normal or ideal occlusion might be sufficient to mirror the subjective opinion of orthodontists about treatment need. The objective of this study was to determine whether the American (US) and United Kingdom (UK) weightings of the peer assessment rating (PAR) index are valid instruments with which to determine treatment need. Fifteen orthodontists rated the need for orthodontic treatment of 170 casts. Their collective decision was compared with the PAR value for the cast determined by a calibrated examiner. A range of suggested treatment cutoff points from the literature was used to generate receiver operating characteristic (ROC) curves and optimized cutoff points. The cutoff points were 17 for both the US PAR and the UK PAR, and sensitivity, specificity, and kappa were 92%, 86%, and 0.77 for the US PAR and 92%, 89%, and 0.80 for the UK PAR. The area under the ROC curve was 97% for the US PAR and the UK PAR. Both the US PAR and the UK PAR scores were excellent predictors of orthodontic treatment need as determined by a panel of orthodontists. An occlusal index used to measure deviation from normal or ideal occlusion might perform as well as indexes of treatment need in predicting orthodontists' evaluations of treatment need.     

Orthodontic treatment need in French schoolchildren: an epidemiological study using the Index of Orthodontic Treatment Need

This survey was undertaken to assess the orthodontic treatment need in a sample of 9- to 12-year-old French children (mean age: 9.77 years; standard deviation: 0.84) attending 12 different schools in the same geographic area of Ile de France. Two examiners used the Index of Orthodontic Treatment Need (IOTN) in order to estimate treatment need. Five hundred and eleven children (268 males, 243 females) who had not previously received orthodontic treatment were examined. Two examiners, who had been previously trained in the use of occlusal indices, screened all the schoolchildren. No radiographs, study casts, or previously written records of the children were used; the IOTN was calculated from direct examination. Qualitative data were analysed using the chi-square test to determine differences in treatment need between subgroups of subjects, and kappa("kappa") statistics to analyse the findings. A correlation coefficient was used to compare professional assessments. Twenty-one per cent of the children presented an objective need for orthodontic treatment, 28 per cent had crowding, 28 per cent an increased overjet, and 15 per cent an increased overbite. The dental health component (DHC) of the IOTN was found to be reliable and simple to use. The malocclusion status of French schoolchildren was lower than that recorded in epidemiological studies of European children.     

正畸治疗指数间的一致性研究

目的:观察不同的正畸治疗指数评价正畸治疗需要的一致性。方法:随机选取220副正畸记存模型,采用常用的4种指数评估这些模型是否需要正畸治疗,并对结果的一致性进行分析。结果:不同的指数鉴定出有不同数量的模型需要正畸治疗(31.6%~85.9%),各指数间的判断结果有显著但弱的相关性,各指数间的一致性较低。结论:采用不同的指数会有不完全相同的结果。     

Associations between orthodontic treatment need and oral health‐related quality of life among young adults: does it depend on how you assess them?

Liu Z, McGrath C, Hägg U. Associations between orthodontic treatment need and oral health‐related quality of life among young adults: does it depend on how you assess them? Community Dent Oral Epidemiol 2011; 39: 137–144. © 2011 John Wiley & Sons A/S Abstract – Objective: To determine the association between orthodontic treatment need (OTN) and oral health‐related quality of life (OHRQoL). Methods: A cross‐sectional study involving 273 young adults seeking orthodontic care. OHRQoL was assessed by the short‐form Oral Health Impact Profile (OHIP‐14) and United Kingdom oral health‐related quality of life measure (OHQoL‐UK). Study casts were assessed for OTN by: Dental Aesthetic Index (DAI), Index of Orthodontic Treatment Need (IOTN)‐Aesthetic Component (IOTN‐AC) and Dental Health Component (IOTN‐DHC) and Index of Complexity, Outcome and Need (ICON). Variations in OHIP‐14 and OHQoL‐UK were determined with respect to OTN, and the magnitude of differences was calculated (effect size: ES). Results: There were significant but weak correlations between occlusal indices scores and OHIP‐14 scores (P < 0.05, r < 0.3) and between occlusal indices scores and OHQoL‐UK scores (P < 0.05, r < 0.4). The magnitude of the statistical difference in OHQoL‐UK scores was moderate to large with respect to OTN (ES: 0.36–0.87) and largest when DHC (ES = 0.87) and ICON (ES = 0.74) were used. The magnitude of the statistical difference in OHIP‐14 scores was relatively lower (ES: 0.21–0.69), but also greatest when DHC and ICON were used to determine OTN (ES 0.69 and 0.50, respectively). Conclusion: Orthodontic treatment need was associated with OHRQoL. The magnitude of the statistical difference between those with and without an orthodontic treatment need was larger when OHRQoL was assessed using OHQoL‐UK compared to OHIP‐14. DHC and ICON were more useful indices in identifying greater differences in OHRQoL with respect to orthodontic treatment need.     

Orthodontic treatment need in Nigerian children

OBJECTIVE: The purpose of this study was to assess the need for orthodontic treatment among Nigerian children aged 12-14 years old in Benin City, south-southern region of Nigeria. RESEARCH DESIGN: The sample consisted of 261 randomly selected school children, 122 boys (47%) and 139 girls (53%) with mean age of 12.9 +/- 0.1. The survey was conducted by clinical examination and both components of the Index of Orthodontic Treatment Need (IOTN) were used to determine the need for orthodontic treatment. RESULTS: The results revealed that 50 (19.2%) of the children had a definite need for orthodontic treatment according to dental health component while aesthetic component of IOTN indicated definite need in 12 (4.6%). Increased overjet, severe contact displacements and impeded eruption of teeth were the common occlusal features in the definite treatment need group. CONCLUSION: This study provided data on the need for orthodontic treatment among Nigerian school children which is useful to plan and prioritise orthodontic care and services.     

The development of the index of complexity, outcome and need (ICON)

This paper is based on the winning submission for the 1998 Chapman prize awarded by the British Orthodontic Society for an essay on a subject promoting the interests of orthodontics. The aim of the investigation is to develop a single index for assessing treatment inputs and outcomes. An international panel of 97 orthodontists gave subjective judgements on the need for treatment, treatment complexity, treatment improvement, and acceptability on a diverse sample of 240 initial and 98 treated study models. The occlusal traits in the study models were scored according to a defined numerical protocol. Five highly predictive occlusal traits were identified (IOTN Aesthetic Component, crossbite, upper arch crowding/ spacing, buccal segment antero-posterior relationships, and anterior vertical relationship) and then used to 'predict' the panelist's decisions using regression analysis. Cut-off values were determined for the dichotomous judgements by plotting specificity sensitivity and overall accuracy. Twenty percentile ranges were used to determine 5 grades of complexity and improvement. The index prediction of decisions for treatment need, had specificity 84.4 per cent, sensitivity 85.2 per cent, and overall accuracy 85 per cent. When used to predict treatment outcomes, the new index had specificity 64.8 per cent, sensitivity 70.1 per cent, and overall accuracy 68.1 per cent. The index could explain 75.6 per cent of the variance in the mean casewise complexity score and 63.5 per cent of the mean casewise improvement score. A new orthodontic index is proposed to assess treatment need, complexity, and outcome. It is based on international orthodontic opinion.     

Variability in recording and grading the need for orthodontic treatment using the handicapping malocclusion assessment record, occlusal index and dental aesthetic index

Abstract This investigation evaluates three malocclusion treatment need indices, the Handicapping Malocclusion Assessment Record (HMAR), the Occlusal Index (OI) and the Dental Aesthetic Index (DAI), for reliability and inter-index correlation. Pretreatment study models of 30 cases (mean age 12.9 years, SD 1.2) were assessed using each index. All the indices demonstrated a high level of reliability and non could be selected over the other with regards intra-examiner differences. The DAI, however, was more time-saving (2.68 mins, SD 0.41) and simple lo use. The highest correlation was between HMAR and OI (r=0.87, P<0.001) which is a reflection of the similarity in their design. This study also discusses the limitations of the three indices.     

Index of orthodontic treatment need as a predictor of orthodontic treatment uptake

INTRODUCTION: The aim of this study was to evaluate whether the index of orthodontic treatment need (IOTN) could be weighted by using consumer-based sociodental measures to predict the uptake of orthodontic services. METHODS: The sample consisted of 525 schoolchildren, 11 to 12 years old, from Greater Manchester, United Kingdom. Child-perceived IOTN aesthetic component (AC), examiner IOTN AC and dental health component, and child socioeconomic status (Townsend score) were recorded. Two consumer sociodental measures (utility and oral aesthetic subjective impact scale values) were recorded. Three years later, the proportion of the subjects who had received orthodontic treatment or were on a waiting list for orthodontic treatment was recorded, and the rate of service uptake was determined. RESULTS: Sociodental indicators did not predict uptake of orthodontic services. A child with higher normative clinical treatment need was 3 times more likely to receive orthodontic treatment than a child with low clinical need (P < .05). CONCLUSIONS: Consumer-based sociodental information does not predict future use of orthodontic services. Factors such as clinical IOTN and child-perceived IOTN AC will adequately predict use of orthodontic services.     

Quality control in orthodontics: indices of treatment need and treatment standards

Two reliable and valid occlusal indices have been developed to assess treatment need (Index of Treatment Need, IOTN) and the standard of treatment (The PAR Index, Peer Assessment Rating). The IOTN assesses both dental aesthetics and dental health need. The PAR index provides a single summary score for the overall alignment and occlusion. The difference between the pre- and post-treatment scores reflects the degree of improvement and the success of orthodontic intervention and active treatment. Several practical uses of the indices are described: the estimation of treatment need in an unselected and a referred population and the assessment of the standard of treatment in the Hospital and General Dental Services. It has been suggested that the use of the occlusal indices would offer several advantages: (1) uniformity in prescribing patterns, (2) safeguards for the patient, (3) patient counselling and (4) monitoring and promoting standards.     

Conference Report

Abstract

The criteria that dentists use to judge the need for orthodontic treatment are not clear. This study investigates variation in dentists' perception of orthodontic treatment need. Seventy-four dentists were asked to assess 320 dental casts in relation to aesthetic and dental health need. The results of this investigation revealed that the panel was divided as what constituted a need for orthodontic treatment on dental health grounds. It is suggested that one method of achieving a more uniform evaluation of orthodontic treatment need is the use of an occlusal index. Until an occlusal index is accepted and used by the profession, the distortion of need and demand for orthodontic treatment by dentists' unequal perceptions will continue.