Patient Expectations of Aligner Treatments Taking into Account Oral Health-Related Quality of Life – a Prospective Multi-Centre Study

Problem formulation: Increasingly more people are attaching importance to correct tooth alignment and opting for orthodontic treatment. The question often arises as to which treatment should be chosen if a treatment with either fixed appliances or transparent aligners is possible. Questions such as "Are there any restrictions in terms of well-being, eating and drinking habits, and professional activity" arise. What patient concerns and expectations of the therapy itself arise before treatment with Invisalign®? The orthodontic treatment of patients has received increasing attention in recent years. Among other things, this can be explained by the increased interest in an aesthetically pleasing appearance of many patients [1–3]. For this reason in particular, increasingly more patients are choosing the form of orthodontic treatment based on aesthetic parameters [3–5]. This also places new demands on day-to-day practical work in the private practice sector [6]. Understanding the views and wishes of patients is essential for being able to provide the most favourable treatment possible [7]. When it comes to the expectations of a successful and satisfactory orthodontic treatment, there are often considerable differences between patients and practitioners [8-10]. This is because patients also judge the success of an orthodontic treatment based on their personal experience with it [11].  

It therefore makes sense that there is an increased interest in understanding the expectations and experiences of patients during their orthodontic treatment [8–11]. One way of assessing these parameters is by means of the "Oral Health Impact Profile 14" (OHIP-14) questionnaire developed by Slade and Spencer in 1994 [12]. It originally contained 49 questions in seven subcategories but was then condensed to 14 questions [12–15]. The OHIP-14 is now regarded as one of the most established methods for assessing the seven dimensions (functional limitation, physical pain and physical disability, psychological discomfort and psychological disability, and social disability and handicap) [13–15]. The oral health-related quality of life (OHRQoL) measured by OHIP-14 includes the patient’s perspective on their oral health and psychological well-being [16,17]. This OHRQoL is defined by the World Health Organisation as a state of physical, mental, and social well-being, including bio-psychosocial aspects [13]. Two questions are asked for each of the dimensions mentioned. These are rated on a scale from zero to four with zero corresponding to no limitation [18]. 

 Question addressed by the study: Are there any special features when answering aligner-specific questions as well as questions about quality of life? This study provides insights into the extent to which there are patient-specific differences in the expectations of an upcoming aligner treatment. Is there a correlation between the expectation of aligner treatment and oral health-related quality of life? Are there correlations between the answers and patient-related parameters such as age, gender, and severity of malocclusion? 

Methodology: As part of a multi-centre questionnaire study, the expectations of the patients regarding orthodontic aligner therapy and their oral health-related quality of life were surveyed.  

Fifty-five patients were included in the study. The patients had to give their informed consent before taking part in the study. In order to make the results more conclusive, patients from the orthodontic department of the University Clinic of Dentistry Vienna and a private orthodontic practice in Vienna were included.  

The study participants decided in favour of treatment with the Invisalign® aligner system after being informed about the treatment procedure and alternatives. Subjects were asked to complete the questionnaire after consenting to Invisalign® treatment and before starting treatment. They were categorised according to gender, age groups (18-25a; 26-35a; 36-45a; 46a and older), and level of education (basic school-leaving qualifications, higher education entrance qualification, apprenticeship qualification, university degree). 

Each of the questionnaires was also combined with an established dental questionnaire, the "Oral health-related quality of life questionnaire". This is a short version of the Oral Health Impact Profile (OHIP) in German. The OHIP is a validated instrument for assessing the oral health-related quality of life in adults. This means that general questions on oral health can be evaluated in a standardised way. These 14 questions are added to the aligner-specific questionnaire. 

Data collection has already been completed. Statistical analyses are currently being carried out and will be completed in the next few weeks. 

Objective: The aim of this study is to find out how the quality of life of patients prior to aligner therapy influences their expectations of treatment and to what extent the responses in relation to patient expectations differ depending on patient-specific parameters. Although there are many publications on the subject of fixed orthodontic therapy, there are only few on the subject of aligner therapy. This study is intended to contribute to improving this knowledge.