Dentistry and Medical Research

: 2019  |  Volume : 7  |  Issue : 1  |  Page : 3--11

Patient-reported outcome measures in orthodontics

Elbe Peter1, RM Baiju2, Jolly Mary Varughese3, NO Varghese3,  
1 Department of Orthodontics, Government Dental College, Kottayam, Kerala, India
2 Department of Periodontics, Government Dental College, Kottayam, Kerala, India
3 Joint Director of Medical Education, Government of Kerala, Thiruvananthapuram, Kerala, India

Correspondence Address:
Elbe Peter
Department of Orthodontics, Government Dental College, Kottayam, Kerala


Psychological perspective of orthodontic patients due to malocclusion and treatment is less explored in orthodontics until recently. Use of psychometric tools is the method to measure this intangible dimension of malocclusion and treatment. However, many generic and condition-specific tools are available now for this purpose. Patient-reported outcome measures (PROMs) will supplement normative outcome measures in the future and will remain an important aspect in patient-centered orthodontic care. In general, with the use of these tools, there has been a conflicting report regarding the effect of malocclusion on a person's Oral Health-Related Quality of Life (OHRQoL). However, orthodontic treatment has shown consistently to improve OHRQoL though there is a transient worsening in the initial phases of treatment. The effect of self-esteem and psychosocial well-being as mediators influencing OHRQoL and contextual factors such as socioeconomic status and family support mechanism on QoL need further evidence from long-term studies.

How to cite this article:
Peter E, Baiju R M, Varughese JM, Varghese N O. Patient-reported outcome measures in orthodontics.Dent Med Res 2019;7:3-11

How to cite this URL:
Peter E, Baiju R M, Varughese JM, Varghese N O. Patient-reported outcome measures in orthodontics. Dent Med Res [serial online] 2019 [cited 2020 Oct 30 ];7:3-11
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The main benefit of orthodontic treatment is improvement in oral function and appearance leading to improvement in psychological and social well-being.[1] Traditionally, malocclusion and treatment need is assessed using normative criteria like classification systems or indices.[2],[3] Both these qualitative and quantitative means ignore patient's psychological status. This dimension to health was added by the World Health Organization (WHO) in 1948 after it broadened the definition of “health.” Dentistry and specifically orthodontics was quite late to adopt this in the specialty. In the early 2000s onward, there appeared articles in orthodontic literature related to Oral Health-Related Quality of Life (OHRQoL) and malocclusion. According to WHO, if an anomaly is to be regarded as one requiring treatment, it should be causing a disfigurement or functional defect or is likely to affect patient's physical or emotional well-being.[4] From this standpoint, there is clear justification for orthodontic treatment. The objectives of orthodontic treatment according to Jackson's triad are structural balance, functional efficiency, and esthetic harmony. With the new concept of QoL paradigm, it is obvious that these objectives should work on an OHRQoL platform and assessed accordingly [Figure 1]. The impact of malocclusion on OHRQoL has been debated; however, a recent systematic review showed that malocclusion has a definite impact on an individual's QoL, and orthodontic treatment improves it.[5]{Figure 1}

Patient is the center of any health-care system, and recently, there has been a realization of this patient-centered health-care model. According to US Food and Drug Administration, a patient-reported outcome measure (PROM) is “any report of the status of a patient's health condition that comes directly from the patient, without interpretation of the patient's response by a clinician or anyone else”. In future, PROMs will be the mainstay of outcome assessment compared to clinical and peer assessment or caregiver assessment. Patient-reported experience measures are also used as quality indicators of patient care and safety. In clinical orthodontics, outcome can be assessed by clinician (on patient directly and on study models, X-rays or on photographs), caretaker (e.g. for children), or patient themselves (self-reported).

Even though this article is titled as PROMs, it includes all forms of patient-reported measures for assessing malocclusion and treatment because any such report is obtained through validated tools or questionnaires. It is interchangeably used in this manuscript as QoL measures or scales even though QoL is much broader multidimensional construct than PROM.

 Historical Background

After the WHO[6] defined health as “not only the absence of infirmity and disease but also a state of complete physical, mental, and social well-being,” health-care professionals were reminded that a patient's health was more than just a corporeal state and may be affected by environmental, social, and emotional factors. Until then, researchers were interested in the biological or the medical model of health which is empirically testable by means of controlled experiments. The additions of mental and social element of health lead to the introduction of biopsychosocial model of health. This social science paradigm or QoL aspect of health and disease focuses on dimensions of functioning, well-being, and ability of the individual to perform social roles. It cannot be tested by means of clinical experiments since these models of health are founded in psychology, sociology, and economics, the methodologies of which are alien to physicians and medical researchers.[7]

For better understanding of the phenomenon behind a proposed theory, it can be schematically represented by depicting interrelationships among various concepts. Conceptual model is a schematic representation of proposed etiological linkages believed to be related to a particular problem or disease.[8] It helps to refine the research question and operationalize the idea.

One of the earliest conceptual models of health is proposed by the WHO – the International Classification of Impairments, Disabilities, and Handicaps in the year 1980. In 1988, Locker[9] adapted the WHO model into the oral health scenario and proposed the first conceptual model for OHRQoL. This resulted in a fundamental shift in dentistry from a paradigm emphasizing disease and a medical model of care to one that incorporated a patient-centered perspective. Locker in his conceptual model for oral disease has given five sequentially related abstract concepts, namely impairment, functional limitation, pain/discomfort, disability, and handicap. However, this model did not consider individual and environmental factors which are likely to play an integral role in oral health. In 1995, another model was introduced by Wilson and Cleary[10] which was simple and comprehensive. It is a merger between the prevailing biomedical concept and the emerging social concept. This model is based on five abstract concepts, namely biological/physiological, symptom status, functional status, general health, and QoL plus mentioning of individual and environmental factors. Wilson and Cleary's model is the most widely tested and applied conceptual model in HRQoL. The other commonly discussed HRQoL models are one by Ferrans et al.[11] which is a modification of Wilson and Cleary's model and WHO's International Classification of Functioning, Disability, and Health (WHO-ICF) and another one by WHO's International Classification of Functioning, Disability, and Health: Children and Youth version (WHO-ICF-CY).[12] The latest addition to WHO-ICF-CY was put forth in the year 2007, which covers infants, children, and adolescents also.

Most of the QoL tools developed and tested in dentistry are based on Locker's conceptual model. Masood et al.[13] in 2016 reported that Locker's model is not ideal for orthodontic problems when they found certain altered pathways using structural equation modeling method. Bakas et al.[14] in a systematic review of conceptual models applicable in medical field recommended the use of Ferran's model which is a modification of Wilson and Cleary's model due to the addition of individual and environmental characteristics. However, application of these models as such in orthodontics is questionable due to the peculiar nature of orthodontic problems. Benson et al.[15] in a cohort study to evaluate the relationship between dental appearance, self-esteem, socioeconomic status, and OHRQoL among UK children have used a simplified Wilson and Cleary's model [Figure 2].{Figure 2}


Health has been defined by WHO[6] in 1948 as “not only the absence of infirmity and disease but also a state of complete physical, mental, and social wellbeing.” This has been revised in 1984 as “the extent to which an individual or group is able to realize aspirations and satisfy needs, and to change or cope with the environment.” Dolan[16] defined oral health as “a comfortable and functional dentition which allows individuals to continue in their desired social role.”

In 2016, FDI as part of vision 2020 developed a new definition for oral health with a framework and efforts are underway to measure this new definition.[17] The new definition is, “Oral health is multi-faceted and includes the ability to speak, smile, smell, taste, touch, chew, swallow and convey a range of emotions through facial expressions with confidence and without pain, discomfort and disease of the craniofacial complex.”

The term “QoL” was first used by the British economist Pigou[18] in 1920. Later, after World War II, this term was adapted into other areas such as sociology, politics, and health. The concept of QoL applied in medical field termed as HRQoL[19] has been defined as “people's perception of their position in life in the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns”. In simple terms, it can be defined as “a sense of well-being that stems from satisfaction or dissatisfaction with areas of life that are important” to the individual.[20]

The more specific concept[21] of “OHRQoL” has been defined as “a standard of health of oral and related tissues which enables an individual to eat, speak, and socialize without active disease, discomfort, or embarrassment.” Inglehart andBagramian[22] defined it as “the absence of negative impacts of oral conditions on social life and a positive sense of dentofacial self-confidence.”

 Need for Patient-Reported Outcome Assessment in Orthodontics

Any objective measure of malocclusion or treatment outcome need to be supplemented with patient-reported measures due to the following reasons:

There is a disparity observed between patient-reported measures and objective measuresPatient's rating of their problems or outcome need not necessarily correlate with those of clinician's rating.

Burdenet al.[23] claimed that orthodontic treatment provides benefit in four main areas resulting in a reduced susceptibility to dental caries, periodontal disease, temporomandibular joint problems, and traumatic dental injury. However, these benefits are objective and are easily measurable. The psychological gain following orthodontic treatment can be measured only using psychometric tools.

O'Brien et al.[24] reported that most QoL assessment tools developed and validated in dentistry are not applicable for orthodontics because of the nature of the orthodontic problem. Malocclusion is mere anatomic variation, and pain or discomfort is not usually associated with it.

 Essential Features and Types of Patient-Reported Outcome Measures

Scales, psychometric tools, validated questionnaires, etc., are often interchangeably used as measures to record this psychological dimension of health. They are developed and validated based on strict psychometric principles and theory. Any psychometric instrument should be valid, reliable, and should demonstrate responsiveness, i.e. ability to detect change over time.[25] A brief description of each feature is presented in [Table 1]. Any HRQoL tool should include domains such as physical status, psychological status and wellbeing, social interactions, economic or vocational status, and religious or spiritual status. Cunningham and Hunt[26] identified some problems in HRQoL research; they are lack of proper definition for QoL, lack of gold standard tool for comparison, lack of proper research question before studying HRQoL, and cumbersomeness of the tool. Currently, there are two criteria available to evaluate HRQoL measures. One by Gill and Feinstein[27] and another by Guyatt and Cook.[28] Brown[29] proposed certain guidelines for researchers studying HRQoL; they are correct choice of instrument, timing of measurement, and frequency of measurement.{Table 1}

The tools used to assess patient-reported measures in orthodontics can be divided into generic and condition specific (CS). The generic tools used extensively in orthodontics include Oral Health Impact Profile[30] (OHIP-49 and OHIP-14), Oral Impacts on Daily Performance (OIDP),[31] and Child Oral Health QoL Questionnaires (COHQoL).[32] The frequently used CS measures include Orthognathic QoL Questionnaire (OQLQ),[33],[34] Psychosocial Impact on Dental Aesthetic Questionnaire (PIDAQ),[35] and Malocclusion Impact Questionnaire (MIQ).[36],[37]

 Commonly Used Generic Tools in Orthodontics

Oral Health Impact Profile

Slade and Spencer[30] in the year 1994 developed OHIP based on Locker's Conceptual model[9] which is in turn an adaptation of the WHO's Classification Of Impairments, Disabilities, and Handicaps. The original instrument consisted of 49 items in 7 domains. The domains were functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. OHIP has been translated and validated and cross-culturally adapted to various languages. Though it is a generic questionnaire, it had been used extensively in orthodontics also. A short form of OHIP with 14 items in 7 domains has been developed in 1997 by Slade.[38] In spite of being short, it is found to be reliable and valid, sensitive to change, and demonstrated adequate cross-cultural consistency.

Oral Impact on Daily Performance

The OIDP index was developed byAdulyanon and Sheiham[31] in1997 based on Locker's Conceptual model which has three levels: oral status and impairments, intermediate impacts (pain, discomfort, functional limitations, and dissatisfaction with appearance), and ultimate impacts (psychosocial and physical disability and handicap). While the majority of OHRQoL instruments focus on measuring the second level, the OIDP puts emphasis on the third level to determine oral impacts on the ability to perform everyday activities. It measures oral impacts on eight performances, i.e. eating, speaking, cleaning teeth/denture, sleeping and relaxing, emotional stability, smiling, carrying out main role/everyday activities, and social contacts. This tool can be modified as a CS OIDP by selectively using those attributes related to malocclusion alone.[39] Gherunpong et al.[40] in 2004 developed a child version of OIDP which can be used both as generic and CS measure.

Child Oral Health Quality of Life Questionnaire

The COHQoL questionnaire[32],[41] is made up of five instruments: the Parental–Caregiver Perceptions Questionnaire (P-CPQ), which measures parent's or caregiver's perceptions regarding the impact of children's oral health on QoL; the Family Impact Scale, which assesses the impact on the family; and the CPQ, which assesses children's perceptions regarding the impact of oral health on QoL. There are three versions of the CPQ, one for each of three specific age groups: 6–7, 8–10, and 11–14 years. Though it is a generic tool, it has been used extensively among orthodontic patients. CPQ11-14 is a self-administered questionnaire popular for orthodontic use because of the age for which it is used. There are 37 questions that ask about the frequency of events in preceding 3 months arranged in 4 domains; 6 questions regarding oral symptoms, 9 questions about functional limitations, 9 questions related to emotional well-being, and 13 questions related to social well-being. The same authors also developed a short form of CPQ containing 16 items for clinical use and 8 items for epidemiological use. Marshman and Robinson[42] and O'Brien et al.[43] have reported that the CPQ11-14 is valid in the UK. It has been stated that CPQ will be the generic tool of choice for orthodontic patients.

 Condition-Specific Tools Used in Orthodontics

For CS problems like malocclusion, generic tools are of little value because all such measures are based on existing conceptual model for disease. Malocclusion cannot be considered as a disease; hence pain, discomfort, and functional limitation are of little importance to orthodontic patients. Marshman and Robinson[42] and Locker and Allen[44] have questioned the appropriateness of using generic tools for malocclusion [Table 2]. First CS measure for malocclusion was introduced byMandall et al.,[45] in 1999. It was subsequently named as Oral Aesthetic Subjective Impact Scale (OASIS). They showed that children with high OASIS score were the one who had definite need for orthodontic treatment.{Table 2}

Cunningham et al.[33],[34] in 2000 introduced OQLQ which addresses the subjective impact of orthodontic-specific problems in adults. It was developed for individuals with dentofacial problems requiring orthognathic surgery; hence, the questions were regarding facial appearance. OQOLQ was developed based on the criteria by Guyatt et al.[46] and Juniper et al.[47] Cross-sectional and longitudinal studies have established the validity of the tool.[48]

Klages et al.[35] based on their previous research developed PIDAQ containing 23 items in 4 domains. The domains were dental self-confidence (DSC) with 6 items, social impact (SI) with 8 items, esthetics' concern with 3 items, and 6 items in PI scale. The SI scale and esthetic concern scale contained revised items of OQLQ. DSC scale was based on their previous research and PI scale was newly developed. The uniqueness of the scale is incorporation of DSC domain, which measures positive aspects of dental occlusion. It has been suggested that OHRQoL measures should include questions dealing with well-being and not only detrimental effects of oral conditions. PIDAQ is one of the most widely used CS measures which is translated and validated in Brazil, China, India, France, Malaysia, Malaya, Morocco, Spain, Turkey, and Nepal.

Benson et al.[36],[37] in 2016 developed MIQ, which had 17 items and 2 global questions. Based on an initial qualitative inquiry and item development process, a set of questions were developed, and in the second part of the study, they did a cross-sectional evaluation to establish the reliability and validity. A 3-point response format, Don't/Doesn't = 0, A bit = 1, Very/A lot = 2, was used. This CS tool is applicable for children aged between 10–16 years. The questions were arranged in 3 sections: about how the teeth looks, how the teeth affects life, and about the health and functioning of teeth. However, responsiveness testing, further validation, and cross-cultural adaptation are required and are underway.

 Other Generic Tools Used Along With Condition-Specific Tools to Supplement Oral Health-Related Quality of Life

Several generic scales are used in tandem for OHRQoL assessment. The use of multiple scales are recommended for OHRQoL assessment because of the multidimensional nature of the construct.[26] A single scale cannot measure all the required constructs. Commonly used such supplemental generic scales are SF-36, EuroQoL, sickness impact profile, and General Health Questionnaire. Moderating factors influencing OHRQoL such as self-esteem and psychological well-being also have been subjected to study in orthodontics. Rosenberg's self-esteem scale is the commonly used measure for studying SE of adult orthodontic patients. It consists of 10 questions graded in a four-point Likert scale ranging from “strongly agree” to “strongly disagree.” Higher score means better self-esteem and vice versa. State self-esteem scale and collective self-esteem scales have also been used sporadically among adolescents in orthodontics.[49] Agou et al.[50] used SE subdomain of CHQ-CF87 questionnaire in 11–14-year-old children. Psychological well-being,[51] personality types, perfectionism among orthodontic patients,[52] body image, and body satisfaction[53] have also been studied using psychometric tools in orthodontics.


The aim of this article is to sensitize the QoL paradigm[54] which is in vogue for orthodontic readers. Outcome measure is not restricted to treatment outcome alone; it includes disease outcome also in this context. This is because the measures used to estimate both are same. Many more CS measures befitting for independent treatments such as lingual appliance, functional appliance, or clear aligners can be expected in future. However, any such measure should be based on sound psychometric theory, following strict principles enabling comparison between populations.

Malocclusion and Oral Health-Related Quality of Life

Malocclusion being a developmental problem causing impact in psychological, social, functional, and emotional domain is found to affect an individual's OHRQoL. Esthetic component of IOTN was the first attempt to record patient perception for assessing treatment need. Nonvalidated questionnaires used in research to record this dimension of malocclusion are of little value. Validated CS psychometric tools are the key to record this intangible aspect of malocclusion that enables international comparison. The impact of malocclusion resulting in poor QoL is not consistent in orthodontic literature. O' Brien et al.[43] reported that the most important domain affected due to malocclusion is the psychological and not the functional one. Furthermore, girls showed more impact than boys probably due to the sex effect on perception of health care and orthodontic treatment. Questions related to emotional and social well-being, shyness, embarrassment, being upset, avoidance of smiling, and public interactions are more relevant to an orthodontic patient. Dimberg et al.[5] in a systematic review reported that malocclusions have negative effect on OHRQoL. The four out of six cross-sectional studies considered were of high quality, and the remaining two were of moderate quality, and the domains affected most were emotional and social well-being.

Patients with cleft lip and palate or other dentofacial deformities are thought to have much worse QoL compared to those with minor malocclusions. However, it has been shown that the QoL status of such patients is not worse than those with dental caries.[44] This is because individuals with severe dentofacial problems are mentally prepared to psychological insults quite often than individuals with minor malocclusions. This discordance between patient's perception of health and well-being on one side and normative health status on the other side is known as disability paradox.

Gherunpong et al.[55] evaluated a sociodental approach in assessing orthodontic treatment need in children. They conceptualized assessment of treatment need at 3 different levels. Normative need based on the assessment of treatment need using indices, classification systems, or cephalometric criteria. Impact-related need by using an OHRQoL measure that records the impact in various domains and propensity-related treatment need is based on oral hygiene status and patient compliance in addition to above two. This classification allows prioritizing children for orthodontic treatment, especially when treatment is provided by governmental agencies at a low cost. It also helps to differentiate those candidates who will really benefit with orthodontic treatment. Those with high or high to medium propensity-related need will benefit better because of compliance, especially for complex treatments. The level of need is reduced by 70% when compared to normative assessment using intensity-related need; this is reduced further by 80% when assessed using propensity-related need. Those with low propensity require broader behavioral approach of dental care than those detected using normative need.

Orthodontic treatment and Oral Health-Related Quality of Life

Orthodontic treatment has shown consistently to improve OHRQoL.[56],[57],[58] Palomares et al.[59] in a cross-sectional study demonstrated that individuals who had a history of orthodontic treatment had a better OHRQoL compared to those without treatment. Javidi et al.[60] in a recent systematic review identified modest improvement in QoL among those who had undergone orthodontic treatment before 18 years. However, the studies included were of low to moderate quality.

Fixed appliance and Oral Health-Related Quality of Life

Fixed appliance is the means by which complex malocclusions are treated. However, orthodontic treatment is not without pain and discomfort. Wearing fixed appliance has been shown to worsen OHRQoL. This worsening is maximum during the initial months of treatment. When patients get used to the appliance, OHRQoL score improves and negative impact is not marked after 6 months into treatment. Zhang et al.[61] in 2008 showed that there is worsening of the QoL during the first 6 months into orthodontic treatment using fixed appliance, especially oral symptoms and functional limitations. However, emotional well-being was found to improve during this stage. The period of greatest change was reported in the initial month of placing the appliance. Liu et al.[62] also observed similar initial worsening and later improvement after 6 months suggesting the need for reducing the appliance burden during the initial phases of treatment. A recent study which evaluated the perfectionist nature among orthodontic patients seeking labial or lingual appliance revealed that patients opting for lingual appliance are more perfectionists.[52]

Orthognathic surgery and Oral Health-Related Quality of Life

Orthognathic surgery aims to correct severe dentofacial deformities and normalize facial appearance. Hence, the OHRQoL improvement is expected to be maximum in these patients. However, the pain and discomfort associated with surgical procedure temporarily result in worsening of negative impacts during orthognathic surgery. This initial worsening is followed by improvement in QoL. Kiyak[63] in longitudinal study demonstrated an improvement in QoL following orthognathic surgery. She demonstrated the importance of completing postsurgical orthodontic treatment within 6 months after surgery. There is a confusion regarding the most appropriate OHRQoL tool for orthognathic surgery patients.[64] It has been suggested to use a combination of generic and CS tool in these patients. The improvement in OHRQoL following orthognathic surgery has found to be stable at 2 years,[63] 5 years,[48] and even after 16 years.[23]

Bullying and Oral Health-Related Quality of Life

Bullying is endemic among school children. It is as a situation in which an individual is exposed repeatedly and over time to negative actions by at least one other person. Most commonly targeted dentofacial features for bullying are spacing between teeth or missing teeth, shape or color of teeth, and prominent maxillary anterior teeth.[66] Seehra et al.[67] have shown that children who are bullied due to dentofacial trails were at high risk of having a poor OHRQoL. Al-Omari et al.[68] using CPQ11–14 showed a definite link between poor OHRQoL and bullying due to dentofacial traits and stressed the importance of antibullying programs in school. Hence, it can be presumed that bullying affects emotional and psychological well-being of individuals making OHRQoL worse.

Self-esteem, psychological well-being, and Oral Health-Related Quality of Life

It has been stated that adolescence is the period of self-esteem formation, while Robin et al. in a study consisting of sample aged from 9 to 90 have reported that “self-esteem levels are high in childhood, dropped during adolescence, rose gradually throughout adulthood and declined sharply in old age.” Self-esteem, malocclusion, and orthodontic treatment had been viewed differently by researchers.

Some children are at remarkable level of concern for minor problems than others who are tolerant to complex occlusal problems. This may be due to the presence of moderators influencing QoL. Agou et al.[51] reported that self-esteem of individuals has such mediator role. Those with high levels of self-esteem (SE) demonstrated lesser negative impact on QoL. In another Brazilian study, it was shown that those with low SE were more sensitive to esthetic effects of malocclusion. Onyeaso and Sanu[69] demonstrated those with high SE did not bother for orthodontic treatment even in the presence of malocclusion. In contrast, Clijmans et al.[70] reported that there is no evidence that SE and personality trait have a moderating role in OHRQoL. However, their study was cross-sectional, and sample size was small. Johal et al.[71] in a prospective study showed an improvement in SE following fixed orthodontic treatment though it is considered a stable trait immune to external influences.

Psychological well-being (PWB) is another moderating factor influencing OHRQoL. It refers to general happiness and overall satisfaction with life. Twin studies have shown that PWB is considerably stable over time and is influenced by genetics and inherent personality characteristics. Agouet al.[51] demonstrated that children with high levels of PWB at baseline had better OHRQoL regardless of their orthodontic treatment status and those with low PWB who did not receive orthodontic treatment experienced worse QoL, compared to those who received treatment. Hence, the moderating role of SE and PWB should be considered while studying OHRQoL. Studies have also shown that contextual factors such as socioeconomic status, family type, and access to orthodontic care can also influence OHRQoL.


Patient-centered health care is gaining popularity, and orthodontics is no exception. Validated psychometric tools are employed to record this dimension of orthodontic care. An entire issue of orthodontic journal “Seminars in orthodontics” (2007) has been devoted to this topic about 12 years back. When malocclusion is a condition that requires treatment mostly for esthetic reasons, its reflection perceived in the mind of a customer is of utmost importance. Moreover, the changes brought about by treatment should be measured both objectively using normative criteria and subjectively using patient-reported measures. Treatment is successful only if there is improvement based on both criteria. The legal value of PROM in a consumerist society seeking redressal for any deficiency in service is yet to be tested in a court of law.

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Conflicts of interest

There are no conflicts of interest.


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