Introduction

Unlike the posterior teeth, anterior teeth play a primary important role in the maintenance of an intact arch.1 Although rarely life threatening, anterior teeth loss affects the quality of life in aspects of speech, chewing, aesthetics, self-esteem, psychological and social impacts for individuals.2,3 It was noted that many patients who would accept edentulous spaces in posterior regions, found the anterior teeth indispensable. The leading cause of anterior teeth loss is trauma and upper incisors are the most frequently lost teeth involved in such cases because of their prominent anatomical location in the maxillary bone.4 Apart from injury, anterior teeth loss is also associated with chronic periodontitis5 and its sequelae, as well as caries and congenital absence, making it a nidus for common disease in dental clinics.

The demand for anterior aesthetic restoration is increasing and presents clinical challenges.6,7 Dental implant therapy is currently one of the most commonly used methods of replacing missing dentition. In comparison to conventional prostheses, implant-supported prostheses have a more natural feeling, stability, optimal aesthetics, phonetics and hygiene access with a minimally absorbed residual ridge.8,9 Moreover, they can achieve a positive effect on social rehabilitation of an affected patient.10,11 A previous study revealed that demand for dentures will most likely be requested if the upper or anterior tooth is missing.12 Peck et al. reported that aesthetic, rather than functional factors, may determine a patient's subjective need to replace the missing teeth.13 Anterior aesthetic appeal can help the whole body establish attractiveness and build self-esteem and happiness.14,15,16 On the contrary, decayed anterior teeth were shown to have negative impact on perceptions of facial attractiveness.17

Although it is assumed that there are negative consequences for individuals with missing anterior teeth, little attention has been paid to the psychosocial impact of such treatment. This impact may have varying effects on peoples's daily life; for example, some patients are content with their unfavorable dentition because of their high level of psychosocial tolerance, while others may experience significant barriers to personal and social success.18,19,20 The psychosocial impact of dental aesthetics questionnaire (PIDAQ) is an instrument that assesses the psychosocial impact of dental aesthetics and quality of life (QoL). Previously, this questionnaire has not been used in the study of implantation of anterior teeth.21 PIDAQ contains 23 items, which are established based on the study of dental aesthetic and oral-health-related quality of life.22,23,24 The reliability, validity and applicability of the PIDAQ for young adults in Brazil has been assessed.25 Prior work has also shown that the translated Chinese version of PIDAQ demonstrates good reliability, validity and responsiveness.26 The use of PIDAQ to assess the implant effects of missing anterior teeth may provide a tool to promote exchange between patients and dentists, and may help dentists to better meet patients' requirements.

Thus, the present study was performed to address the psychosocial impact of placing impact-supported prostheses in anterior teeth loss patients using valid and reliable sociodental and psychological measurement. The association between implant and psychosocial traits of dental aesthetics was compared before implant therapy and six months after implant-supported prosthodontic rehabilitation.

Material and methods

Patients

Patients seeking anterior teeth implant therapy to replace their missing teeth were recruited for this study. All clinical procedures were approved by the Ethics Committee of the Jinan Military General Hospital of PLA. An invitation to participate in the study was extended to eligible patients. Each participant was given a detailed explanation of the study, and informed consent was obtained from each participant before inclusion. Patients with cleft lip, cleft palate, cognitive impairment and other serious congenital malformations were excluded from this study, as they may have scoring bias in the PIQAD. Also, participants were excluded if they had had previous implant therapy history or any local or systemic contra-indications to dental implant therapy. Inclusion criteria specified that the overall implant therapy of participants must be successful throughout the entire study period. Patients were excluded if any signs of failure occurred during any stage of the treatment.

Assessment

The assessment of the psychosocial impact of dental aesthetics was surveyed using the Chinese version of PIDAQ. One investigator, trained in PIDAQ, conducted all clinical and radiographic examinations and thoroughly assessed each patient before and after implant therapy. Questionnaires were completed between May 2011 and January 2012, before implant placement, and six months after the completion of implant crown restoration treatment. Age, gender and education level of the patients were recorded before implantation surgery. Patients were requested to fill out questionnaires in the department of stomatology.

The PIDAQ Chinese version consisted of 23 items, grouped into three dimensions: social impact, aesthetic attitude and dental self-confidence. The impact of each item was scored based on the importance of each dimension to the patient. Factor 1 (items 1-8) focused on the social impact of dental aesthetics (social impact). Factor 2 contained items 9-17, which reflected the aesthetic impact of individual attitudes (aesthetic attitude). Factor 3 contained items 18-23 and reflected the individual degree of confidence in dental aesthetics (dental self-confidence). A weight for each dimension was calculated on an individual basis by dividing the summed responses of that dimension by the total possible scale score. To construct an overall score, scores within each dimension were first calculated by multiplying the summed dimension response by the dimension weight. Patients responded to each item by selecting one of three response categories in the form of a Likert response format that included (0, 'never'; 1, 'hardly ever'; 2, 'occasionally'; 3, 'fairly often' and 4, 'very often'). The PIDAQ was used to evaluate how frequently, before and after treatment, each patient had experienced any of the problems mentioned in the three dimensions. All participants completed the questionnaires before implant insertion and again six months after rehabilitation with implant-supported prostheses. The six-month time point following prosthetic rehabilitation has been shown to be an adequate period for the patients to adapt to new prostheses and provide a reliable assessment.27,28 Higher scores of social impact and aesthetic attitude indicate that adverse effects of these two were greater, whereas the dental self-confidence score is proportional to the degree of confidence.

Sample size

In our pilot data of 20 patients, we found a 6.3 point average reduction on the social impact (standard deviation of 5.9) at six months after rehabilitation with implant-supported prostheses. To reach a withdrawal rate of 40%,29 a sample size of 102 patients was required (alpha = 0.05, beta = 0.10), which indicated that our current sample size was appropriate to provide sufficient statistical power.

Statistical analysis

Participants who had two or more missing PIDAQ items or 'don't know' responses were excluded from analysis according to an invalid scale, and for participants with one missing item or 'don't know' response, the value was replaced with the sample mean for the group. All the data were analysed using the statistic software SPSS 15.0 (SPSS Inc. Chicago, IL, United States). All numeric values were presented as median and mean ±SD. We used multivariate analysis to examine the difference of all factor's scores of PIDAQ between before implantation and after implantation. Differences in mean social impact, aesthetic attitude and dental self-confidence scores between the baseline and six-month interval were assessed with the paired t-test or Wilcoxon signed rank test. Comparisons (for example, changes in social impact score from before implantation to after implantation) between males and females, college education and high school education were evaluated using independent sample t-test and Mann-Whitney test. Pearson tests were used to analyse the relation of the scores of PIDAQ and self-assessment of patients. Statistical tests were two-tailed (alpha = 0.05). A p value less than 0.05 was considered as statistically significant.

Results

Of 115 patients, 9 patients were eliminated from follow-up due to changing resident city (five cases) or contact information (four cases). Hence they were excluded from the analysis. One hundred and six patients (64 females and 42 males) completed the scale and clinical examination. The mean participant age was 43.5 ±11.5 years (range from 31-56 years old). The majority of participants (72.6%) held a college degree (or higher) and the remaining 27.4% completed high school education. At six months after implant crown restoration, 24.5% patients thought the aesthetic degree was much better, 70.8% patients felt it was better, 4.7% patients considered it to be similar and no patient chose worse or much worse, compared with before implantation.

Upon clinical examination, the practising dentist did not find any implant or upper structure loose; crown loose, porcelain crack, gingival swelling, food impaction or significant dental calculus and debris.

The PIDAQ score variation between pre- and post-implantation was related to the self-assessment of the aesthetic degree of implant restoration. The correlation coefficients of social impact, aesthetic attitude and dental self-confidence were −0.629, −0.753 and 0.617 respectively. There were significant differences between different self-assessments of the aesthetic degree. The score of dental self-confidence was higher, the score of social impact and aesthetic attitude was lower, and the aesthetic degree of self-assessment was higher (Fig. 1).

Figure 1: The relationship of self-assessment of the oral aesthetic degree after implantation compared with pre-implantation, and scores of the differences between after and before implantation.
figure 1

The asterisk represents p <0.05 comparing different self-assessment of oral aesthetic degree. The correlation coefficient of the score differences and social impact, aesthetic attitude and dental self-confidence was −0.629, −0.753 and 0.617 respectively

Full size image

Compared with pre-implantation, at six months after implant crown restoration, the scores of social impact and aesthetic attitude decreased significantly, and the score of dental self-confidence increased significantly. The differences between before implantation and at six months after implant crown restoration were significant (Table 1).

Table 1 The scores of PIDAQ before implantation and after implantation
Full size table

When considering social impact, aesthetic attitude and dental self-confidence from a specific item, when compared with before implantation, the proportion of 'fairly often' and 'very often' in item 4 (inhibited in social contacts), item 13 (feel bad), and item 22 (satisfied with appearance) showed the largest improvement. In short, implantation of missing anterior teeth may decrease the adverse social impact and aesthetic attitude. Additionally, dental self-confidence appeared to be improved (Tables 2,3,4).

Table 2 The proportion of 'often' and 'very often' in social impact in PIDAQ before and after implantation (%)
Full size table
Table 3 The proportion of 'often' and 'very often' in aesthetic attitude in PIDAQ before and after implantation (%)
Full size table
Table 4 The proportion of 'often' and 'very often' in dental self-confidence in PIDAQ before and after implantation (%)
Full size table

Before implantation, the score of aesthetic attitude and dental self-confidence was significantly different between genders. The adverse aesthetic attitude in males was more obvious than in females, but the dental self-confidence in males was not stronger than females. After implantation, the adverse social impact and aesthetic attitude in males was significantly lower than in females, and still there was no significant difference between males and females in dental self-confidence. Compared between pre- and post-implantation, the improvement degree of PIDAQ in males was significantly greater than in females (Fig. 2).

Figure 2: The scores of PIDAQ before and after implantation between males and females.
figure 2

The asterisk represents p <0.05 comparing males and females. a = the scores of social impact with different genders; b = the scores of aesthetic attitude with different genders; c = the scores of dental self-confidence with different genders

Full size image

Before implantation, the patients of a higher education level group obtained higher scores of social impacts and aesthetic attitude than the lower education level group. However, the higher education level group's score of dental self-confidence was lower. After implantation, the score of aesthetic attitude in lower education level was significantly decreased, compared with higher education level. Compared between pre- and post-implantation, the change degree of the score in social impact and aesthetic attitude in lower education level was significantly lower than the higher education level group (Fig. 3).

Figure 3: The scores of PIDAQ before implantation and after crown restoration between different education levels.
figure 3

The asterisk represents p <0.05 comparing the college and high school education levels. a = the scores of social impact with different education levels; b = the scores of aesthetic attitude with different education levels; c = the scores of dental self-confidence with different education levels

Full size image

Discussion

Missing anterior teeth is fairly common30 and the anterior zone is most demanding from an aesthetic, functional, psychosocial and phonetic perspective.31 Oral implantation of missing anterior teeth benefits not only dental health but also the overall and psychological well-being of the patient,32 including confidence and self-esteem.33 Implantation of missing anterior teeth has changed from focusing on a tooth as a unit to a patient as a unit. This paradigm shift is responsible for concern not only about the functional recovery of the tooth, but also the psychological health of the patient.34

Investigations of psychological impact of dental implant therapy are still insufficient. Patel et al. reported that edentulous patients experienced severe psychological complications that can be reduced by implant-supported prostheses.35 Meanwhile, Al-Omiri MK et al. carried out a similar investigation of the psychological influence of dental implant treatment and reported that implant treatments had a favourable effect on pathients.36 In another study, Torres et al. suggested that dental implant therapy has a significant effect on psychological effects when compared with conventional prostheses.37

As a valid and reliable test, the PIDAQ was used to measure the aesthetic profile of subjects before and after implant treatment, as there was no other test regarding oral aesthetic psychology that has been used in oral medicine. This questionnaire was validated for a Chinese population in previous studies and was judged valid and reliable.26 The PIDAQ test measures three dimensions of psychosocial impacts, and is, simply, a reproducible, statistically easy test to use and can be completed in a short time. Studies about PIDAQ should be undertaken in patients undergoing oral restorative treatment in the anterior region38 and implantation of missing anterior teeth is a very important restorative procedure. In this study, each patient was set up as his/her own control. A within-subject control study design promoted the reliability of the current protocol. Our findings demonstrated that implant-supported prostheses improved patients' psychosocial ratings. Additionally, a relationship was established between psychosocial traits and impacts of implant therapy on patient with anterior teeth missing.

Our study showed that the self-assessment of the aesthetic degree after anterior teeth implantation had a relationship with the PIDAQ scores, judged by correlation coefficients of the three factors. The scores from pre- and post-implantation, showed that implantation impacted the adverse effects caused by missing anterior teeth by leading to significant improvements in social impact, aesthetic attitude and dental self-confidence. Changes in the proportion of 'fairly often' and 'very often' after implantation also suggested that restoration of missing anterior teeth can improve the patients' quality of life.

In considering social impact, the treatment of implantation had the best improvement in 'inhibited in social contacts', which can increase the patients' self-esteem and social interaction capabilities. Before implantation, most people in the aesthetic attitude 'wished teeth looked better', which was a direct response of the impact from missing anterior teeth. And the biggest improvement of 'satisfied with appearance' in dental self-confidence showed that implantation in anterior teeth had a close relation with the improvement of patients' appearance.

The patient sample contained a higher percentage of females than males. A common preconception is that females have more critical oral demands and are more concerned about their dental status.39,40 Meanwhile, males are less demanding with regard to appearance and performance because of the nature of their social life.41 In contrast, a prior study found that men regarded dental appearance as more important than women42 and other studies found that the differences were not significant.43,44 In the current study, the adverse aesthetic attitude and dental self-confidence of males was more obvious than females when anterior teeth were missing before implantation. This can be explained by the opinion that females are typically more stable psychologically and lead a less stressful social life than males.45 After implantation, the results showed the same tendency: that social impact, aesthetic attitude and dental self-confidence were more improved in males than females, which suggested that males expressed greater satisfaction with implantation treatment in anterior teeth. Females were more critical regarding their dental appearance and function.46,47,48,49

There was a relationship between education level and dental aesthetic satisfaction. With an increase in education level, the dissatisfaction with dental aesthetics decreased.50 In this study, the higher education level population chose implantation when anterior teeth were missing more than the lower education level. These results suggested that a higher education level population had knowledge that there is some link between dental appearance and social status expressed by better jobs and social acceptability.51

After implant treatment, the social impact and aesthetic attitude of patients with higher education had improved more than patients with lower education, but there were no significant differences in dental self-confidence. This suggested that the higher education level population paid more attention to adverse social impact and aesthetic attitude resulting from missing anterior teeth than the lower education level population. However, the change in the degree of dental self-confidence had no relation to education level.

Our current study has some limitations. Firstly, the current sample size is relatively small, although it can provide sufficient power. Once stratified, the sample size is even smaller, which further reduces the statistical efficacy. Secondly, the current study lacks long-term follow-ups, such as one year or longer after implantation. What's more, our study analysed only limited social factors such as gender and education level. Other factors, such as skill of the operating dentist, degree of missing teeth (single loss, multiple loss, partial loss etc), implanting materials, health condition, income, etc, are also very important to the psychological impact. Hence, additional studies with larger sample sizes, longer follow-up time, diverse impact factors, and comparison of implantation to traditional restorative treatment protocols are needed to further investigate the potential psychological effects of implantation on dental aesthetics.

Conclusion

PIDAQ is an instrument that assesses the psychosocial impact of dental aesthetics and quality of life. The aesthetic degree following implantation correlated negatively with the scores of social impact and aesthetic attitude, but positively with the scores of dental self-confidence. Implantation of anterior teeth significantly improved adverse psychological and quality-of-life effects precipitated by missing anterior teeth. Gender and education level both significantly affected PIDAQ before implantation and after crown restoration. This study showed that PIDAQ could be used as an important tool for assessing the treatment effects of implantation in patients with missing anterior teeth.