Which factors influence willingness-to-pay for orthognathic treatment?

The aims of this interview-based questionnaire study were to establish which factors influence willingness-to-pay (WTP) for orthognathic treatment and to compare WTP values, from both members of the general public and orthognathic patients, with the actual cost of treatment, the hypothesis being that the more highly valued the intervention, the higher the WTP value. Data were collected from 88 orthognathic patients and a convenience sample of 100 adults using the so-called 'payment card' method. Demographic data were recorded, as well as ability to pay, incisor relationship, occupation, and level of education. In addition, the resources used in orthognathic treatment were estimated for five patients who participated in the study. The results showed that there was a significant difference between the mean WTP values for the public and patient groups. Patients were prepared to pay [see symbol in tex]2750 more than members of the general public. In addition, a significant relationship was found between WTP and incisor relationship in the patient group, with Class II division 1 patients prepared to pay [see symbol in text]3130 more than those with Class III malocclusions. Ability to pay did not significantly affect WTP. The mean total costs estimated for orthognathic treatment were lower than the mean patient WTP value and similar to the mean WTP value for the public group. In terms of cost-benefit, it appears that orthognathic treatment provides 'good value for money'. This study also showed that both patients and the general public were prepared to place a monetary value on the correction of dentofacial deformity and that this form of economic evaluation is a useful tool in monitoring health care in the UK.

How to write a thesis

The prospect of writing a thesis can be intimidating. However, there are certain formats that the writer should follow in order to make life much easier. This article covers a logical approach to presenting research findings. Also included are suggestions for a last minute checklist.

How predictable is orthognathic surgery?

There are a number of increasingly sophisticated techniques available for orthognathic treatment planning. All are based on the determination of the skeletal pattern and the position of the dentition. However, they all suffer from difficulties associated with predicting the soft tissue profile. The aim of this retrospective cephalometric investigation was, therefore, to compare the ability to predict accurately the outcome of orthognathic treatment using the 'hand planning' technique and the orthognathic planning and analysis (OPAL) computer program, with an emphasis on the soft tissue profile. Seventy adult subjects were divided into two groups not specific for gender or age: the Class III patients had undergone bimaxillary surgery and the Class II patients sagittal split mandibular advancement. In each group, the pre-treatment and post-debond lateral cephalograms were utilized to calculate the actual orthodontic and surgical movements. These values were then used to produce a prediction using both the hand planning technique and the OPAL program. The resultant predictions were digitized using a customized computer program and compared with the actual outcome. The results show that there was marked individual variation when planning by hand and using the OPAL program. In the mandibular surgery group, hand planning and OPAL were of similar accuracy and few points differed significantly between prediction and outcome. However, for the bimaxillary group, a number of points showed bias and the hand planning technique appeared to be more accurate than the OPAL program, particularly in the region of the lips. Although the usefulness of predictions is acknowledged, these results suggest that they should be used with a certain amount of caution.

How to...write a paper

Writing a paper may seem like a daunting process for the inexperienced researcher (and sometimes for those who are experienced!). However, this does not need to be the case if the approach is logical and systematic. This article covers some of the most important aspects of writing a scientific paper.

A cost-utility analysis of patients undergoing orthognathic treatment for the management of dentofacial disharmony

INTRODUCTION

Management of dentofacial discrepancies using orthognathic treatment is now a common procedure in the United Kingdom. Although the benefits of orthognathic intervention are often considered, the cost implications have not been investigated to our knowledge. This study is a cost-utility analysis of orthognathic treatment.

PATIENTS AND METHODS

Twenty-one patients were interviewed five times during treatment using the time trade-off (TTO) method to establish utility values. Quality adjusted life years (QALYs) gained as a result of treatment were calculated and discounted. The resource use was calculated for each of the 21 patients individually and the costs subjected to both a sensitivity analysis and discounting. The incremental mean cost per additional QALY was calculated (as compared with a 'no treatment' approach).

RESULTS

The incremental cost for each additional QALY was 561 pounds sterling for the groups combined, based on mean additional costs and QALYs (546 pounds sterling for the bimaxillary group and 617 pounds sterling for the single jaw group).

DISCUSSION

Orthognathic treatment seems to provide good outcomes at relatively low cost. Even allowing for the uncertainty in mean costs and QALYs, there is a high probability of treatment being cost-effective. Cost-utility analysis is still a relatively new technique in dentistry and further studies should be encouraged.

A comparison of parents' and patients' views of orthognathic treatment

The aim of this study was to assess parents' views of orthognathic treatment and compare them with the views of their son or daughter who underwent the treatment. Fifty patients who had undergone orthognathic treatment and one of their parents were recruited over an 8-month period between July 1999 and March 2000. The study was a retrospective, questionnaire-based study. Comparison of parents' and patients' views was undertaken using Cohen's kappa coefficient. This was also used to compare individual parent and patient views pre- and posttreatment. Response rates were 90% (n = 45) for patients and 80% (n = 40) for parents. Parents rated their son or daughter as having a more attractive facial and dental appearance and higher levels of self-confidence both pre- and posttreatment than the patients graded themselves. Parents and patients both felt there was significant improvement in facial and dental appearance and self-confidence following treatment.

Development of a condition-specific quality of life measure for patients with dentofacial deformity: II. Validity and responsiveness testing

The assessment of quality of life is becoming increasingly important in dentistry. This may be measured using two groups of instruments: generic and condition-specific.

OBJECTIVES

This paper describes the processes of validity and responsiveness testing of a condition-specific quality of life measure for patients who present with severe dentofacial deformity requesting orthognathic treatment (the so-called Orthognathic Quality of Life Questionnaire). The development of the instrument is described in a previous paper.

METHOD

The OQLQ was tested for validity using a visual analogue scale and also the Short-Form 36 health survey questionnaire. Responsiveness was tested using longitudinal data obtained before, during and after orthognathic treatment.

RESULTS AND CONCLUSIONS

The OQLQ shows good evidence of validity and responsiveness. This, together with previous evidence of good reliability, suggests that the instrument may prove useful in both clinical trials and in quality assurance.

Advances in orthodontics

There has been tremendous progress in orthodontics since Edward Angle first popularised the fixed orthodontic appliance at the turn of the century. Recent years have seen an increased demand for orthodontic treatment from both adolescents and adults and, in addition, patient and clinician expectations of treatment outcomes continue to rise. A desire for more aesthetic materials has resulted in both smaller and 'tooth-coloured' appliances. Improvements in technology, often outside orthodontics, have also led to the development of new materials. The best example of this was the development of nickel titanium alloy by the NASA space programme, which was subsequently adapted for use in nickel titanium archwires. Other technological advances adopted for use in orthodontics include magnets, computerised imaging systems and distraction osteogenesis. This review paper looks at some of the innovations in the fields of materials as well as in techniques and appliance systems.

Are pre-treatment psychological characteristics influenced by pre-surgical orthodontics?

A number of investigations have looked at psychological changes occurring in association with orthognathic treatment. However, most of these studies have used a pre-surgery questionnaire as the baseline measurement. There is little data relating to the true baseline, i.e. that prior to any active treatment. Until this aspect is investigated, it is not possible to assume that pre-surgery is an acceptable baseline. This questionnaire based study aimed to assess changes in six psychological outcome measures between T1 (prior to any active treatment) and T2 (following pre-surgical orthodontics/prior to surgery). The outcome variables were: state anxiety, trait anxiety, depression, self-esteem, body image, and facial body image. Sixty-two patients (39 females and 23 males) completed both questionnaires. The results showed that intervention, in the form of orthodontic treatment, had a minimal effect on the chosen psychometric outcome variables. There was a significant reduction in satisfaction with body image amongst patients who initially reported mild to moderate dental/facial problems, whilst a moderate increase in satisfaction occurred in those patients reporting severe conditions initially. Also of note were significant increases in state anxiety amongst older patients whilst trait anxiety showed greater increases in females than males.

An introduction to economic evaluation of health care

Economic evaluation is an accepted method for the appraisal of health care programmes. Although it is used widely in medicine, its use in the field of dentistry has achieved popularity more recently. Economic evaluation in dentistry is likely to become increasingly important in the future and this paper introduces readers to some of the basic concepts.

Quality of life and its importance in orthodontics

Over the last 10-15 years, the terms quality of life (QOL) and health-related quality of life (HRQL) have been seen increasingly in medical literature. Much of the orthodontic treatment that is undertaken is justified on the basis of improving health-related quality of life. With this in mind, studying HRQL in orthodontic patients has the potential to provide information about treatment needs and outcomes, and may also facilitate improved care. Clinicians should therefore be aware of some of the ways in which health-related quality of life may be assessed. The first part of this review article looks at the general concepts of health-related quality of life, whilst the second section focuses on dentistry and orthodontics.

A comparison of information retention at an initial orthodontic consultation

The exchange of information is an everyday part of orthodontic treatment. However, the amount of information that is understood and retained, by patients and their parents, is not known. There has been very little research in the area of information retention in dentistry. This has implications with the demands for improved provision of information for patients. This questionnaire-based study, compared the effectiveness of written, verbal, and visual methods of providing orthodontic information. It assessed the retention of this information, by patients and parents, in both the short- and long-term. Twenty-eight patients and their parents, were allocated alternately into one of three groups, receiving written, verbal, or visual information. Short-term retention of knowledge was assessed 10-15 minutes after receiving the information and long-term retention rated by a second questionnaire mailed 8 weeks later. Overall, little difference was found between the three methods. The findings suggested that verbal information should not be given to patients unless supplemented by written and/or visual information, and that parents were more attentive to verbal instructions than their children.

The application of multilevel, multivariate modelling to orthodontic research data

OBJECTIVE

To demonstrate the use of multilevel multivariate modelling in the evaluation of multiple outcome dental data.

BASIC RESEARCH DESIGN

Multiple outcome dental research data are used to illustrate the problems of analysing such complex information structures i.e. several outcomes clustered within subjects. Appropriate and statistically efficient methods of data analysis are proposed and illustrated step-by-step. The data structure is analysed using multilevel multivariate regression techniques and this process is discussed in comparison to conventional single-level multiple regression.

PARTICIPANTS

Questionnaire data were obtained from an orthognathic study of 84 subjects seeking treatment and 106 'non-treatment' controls (full details of which are reported elsewhere).

RESULTS

Multivariate multiple regression analysis demonstrated a number of advantages over separate single-level multiple regression approaches, including a gain in statistical efficiency and greater insight into: a) the role of (significant) explanatory variables and b) outcome variable interactions. Multilevel multivariate analysis reduced the risk of both Tipe I and Type II statistical errors.

CONCLUSIONS

The study demonstrates the benefit of multilevel multivariate modelling over conventional single-level techniques for statistical analysis of multiple outcome data. As a result of ongoing technical developments in the power, speed and memory of modern PCs, multilevel multivariate regression can now be undertaken with relative ease. Consequently, researchers are better equipped to analyse such complex data structures, particularly within dentistry where multivariate data are common.

A comparison of the perception of facial profile by the general public and 3 groups of clinicians

Orthodontists and maxillofacial surgeons frequently plan orthognathic treatment to produce an "ideal" Class I occlusion and skeletal relationship. The aim of this study was to investigate whether the preferred facial profile chosen by orthodontists, maxillofacial surgeons, dental students, and members of the general public conformed to a Class I profile. Photographs were taken of 2 male and 2 female adult subjects with Class I profiles, and by means of a computer program the images were manipulated to produce Class II, Class III, and long face profiles. The orthodontists, surgeons, dental students, and members of the general public ranked each group of 4 photos in order of their attractiveness. Orthodontists and maxillofacial surgeons were found to be significantly more likely to choose a Class I skeletal relationship as the most attractive profile. A significant difference was found between orthodontists and dental students (P < 0.01) and between orthodontists and the general public (P < 0.001) with regard to the assessment of the Class I profile as the most attractive, when all 4 subjects were considered. Similar results were noted for maxillofacial surgeons. Whether the assessor was an orthodontist, maxillofacial surgeon, or a member of the general public was found to be significant when examining subjects 1 (female) and 3 (male). The sex of the assessor was also a significant factor for subject 3 (male), where female assessors were more likely to rank the Class I profile as most attractive (P < 0.05).

Development of a condition-specific quality of life measure for patients with dentofacial deformity: I. Reliability of the instrument

The assessment of quality of life is becoming increasingly important in clinical research. Its importance in dentistry has been realised only relatively recently. Health-related quality of life is concerned with the aspects of quality of life that relate specifically to an individual's health. This may be measured using two groups of instruments: (i) generic measures, which provide a summary of health-related quality of life and sometimes generate a single index measure of health or (ii) condition-specific measures, which focus on a particular condition, disease, population or problem and are potentially more responsive to small, but clinically important, changes in health.

OBJECTIVES

The aim of this study was to develop a condition-specific quality of life measure for those patients with severe dentofacial deformity who were requesting orthognathic treatment and to assess the reliability of this instrument.

METHOD

Instrument content was derived through a literature review and interviews with clinicians and patients. The resulting instrument was tested for internal consistency and test-retest reliability.

RESULTS AND CONCLUSION

The instrument was found to divide into four clinically meaningful domains. Internal consistency and test-retest reliability were good. Patient acceptance of the questionnaire was also encouraging.

A comparison of health state utilities for dentofacial deformity as derived from patients and members of the general public

The cost-utility approach is a method of economic evaluation, which assigns a ratio of cost to benefit, based on utility values of the health state in question. It allows efficient use of health care resources and is a useful method in that it permits comparison of a wide range of medical interventions, including those which are life saving and those that improve quality of life. This study obtained utility values for dentofacial deformity from orthognathic patients and members of the general public using three recognized methods--rating scale (RS), standard gamble (SG), and time trade-off (TTO). There were no significant differences between the utility values for the two groups of respondents. Method agreement between the TTO and the SG (the 'gold standard') was better than that between the RS and SG. In addition, the SG and TTO were found to have greater repeatability than the RS.

Relationship between utility values and willingness to pay in patients undergoing orthognathic treatment

OBJECTIVE

To determine utility and willingness to pay (WTP) values for patients undergoing orthognathic treatment in a National Health Service hospital in the United Kingdom and to establish whether WTP values can be used as a measure of strength of preference.

PARTICIPANTS

Forty patients who were about to start orthognathic treatment were recruited over a 10-month period between January and October 1998.

OUTCOME MEASURES

Utility values were obtained using the standard gamble method and WTP values were determined using a payment card method. The relationship between the two was assessed.

RESULTS

The mean utility value was 0.73 and the mean WTP was 6,833 pounds. The correlation between these two measures was -0.46 (P<0.01).

CONCLUSIONS

The correlation between the utility and WTP values was in the expected direction thus suggesting that WTP may be used as a measure of strength of preference. Therefore, willingness to pay may be a useful technique to combine with cost utility analysis.

Are orthognathic patients different?

This questionnaire-based study investigated the psychological profile of orthognathic patients prior to starting treatment and compared the findings with a control group of non-patients. Comparison of the data used multivariate multiple regression analysis where outcome variables and independent variables were studied simultaneously. Some differences were found in the psychological profile of the orthognathic patient. They displayed higher levels of state anxiety (P < 0.001), higher numbers of individuals in their social support network (P < 0.05), and lower body image and facial body image (P < 0.001). Self-esteem was also found to be lower, but only at borderline levels of significance (P = 0.052).

Economic evaluation of healthcare--is it important to us?

Economic evaluation is now an accepted method for the appraisal of healthcare programmes. Although it is used widely in medicine, its use in the field of dentistry is only just beginning to achieve popularity. Economic evaluation in dentistry is likely to become increasingly important in the future and this paper aims to introduce the basics of the technique as well as describing some of the dental settings in which it is currently being used.

Soft tissue changes associated with incisor decompensation prior to orthognathic surgery

A retrospective cephalometric study employing angular and linear measurements was undertaken to examine soft tissue changes associated with incisor decompensation prior to orthognathic surgery. Subjects were divided into 3 groups based on the presenting malocclusion, and radiographs for each subject were traced and subsequently digitized. The results showed that incisor decompensation was achieved more markedly in Class II division 2 and Class III patients. In Class II division 1 subjects, changes in the mandibular incisor inclination were contrary to what was anticipated. The soft tissue change/dental change ratio following incisor decompensation showed that the soft tissues were least affected in the Class II division 2 group. This may be due to the increased tone of the soft tissues in this group, which resisted the effects of the incisor change. Alternatively, it may indicate that the soft tissue "drape" is not in close approximation to the dentition and therefore dental changes are not transmitted to the soft tissues.

The psychology of facial appearance

Facial attractiveness is now recognized as being important in situations as diverse as education, relationships and employment. An individual's facial appearance is one of their most obvious characteristics and facial disfigurements are judged to be among the least desirable 'handicaps'. A face which deviates from the norm becomes a stigma. This paper looks at the complex area of facial appearance and its importance in the field of dentistry. The relationship between facial attractiveness and varying forms of dental and surgical intervention are discussed, as well as some of the problems which may be encountered during treatment.

An investigation into the effects of polishing on surface hardness and corrosion of orthodontic archwires

The purpose of this study was to investigate the effect of surface roughness on the relative corrosion rates of wires of four alloys-stainless steel, nickel titanium, cobalt chromium, and beta titanium. Batches of wire were divided into two groups. Wires in one group were industrially polished to provide a uniform surface finish; wires in the other group were left for comparison "as received." Wire diameter, hardness, and relative corrosion rates were compared within groups before and after polishing. Comparisons were also made across the four groups of alloys. The samples of as-received wires showed variations in surface finish, with beta titanium having the roughest appearance and cobalt chromium the smoothest. Nickel titanium and stainless steel surfaces were similar. Polishing provided a more uniform finish, but significantly reduced the diameter of the wires. Microhardness testing of wire surfaces of each alloy indicated that no significant work-hardening occurred as a result of polishing. The relative corrosion rates (expressed in terms of corrosion current density) in a 0.9% sodium chloride solution were estimated using the electrochemical technique of polarization resistance. Nickel titanium wires exhibited the greatest corrosion current density in the as-received state. Polishing significantly reduced the corrosion rate of nickel titanium, such that comparison between the four alloys in the polished state revealed no significant difference in their relative corrosion rate/corrosion current density.

Providing immunizations in a pediatric emergency department: underimmunization rates and parental acceptance

OBJECTIVES

To assess the vaccination status and vaccinate eligible children with age-appropriate antigens.

DESIGN

Intervention.

SETTING

Pediatric emergency department in an urban, public hospital.

PATIENTS

Convenience sample of children, aged birth through 72 months.

INTERVENTIONS

Immunization of eligible children.

MAIN OUTCOME MEASURES

1) Immunization coverage rates in the sample population, 2) Acceptance rates of immunization.

RESULTS

A total of 9321 children were enrolled over a 2-year period. Fifty-nine percent were documented to be underimmunized. Overall, 2514 children received a total of 6482 immunizations. Parents who carried portable immunization cards documenting that their child was underimmunized were almost five times more likely to accept immunization for their child than parents who lacked documentation (71% vs 15%, P < 0.0001). The estimated cost of providing immunizations in the emergency department was $47.15 per child immunized, or $18.56 per immunization given.

CONCLUSIONS

The majority of children with documentation of immunization status were underimmunized. When documentation of underimmunization was available, parents were significantly more likely to accept vaccination. These data suggest that vaccinating children in nontraditional settings is feasible and support the creation of an accessible vaccine registry.