Oral health‐related quality of life and perceptions of patients following primary root canal treatment or non‐surgical retreatment

Abstract

This retrospective cohort study compared the effect of primary root canal treatment (RCT) with root canal retreatment (Re‐RCT) on patient‐reported outcomes in Kuala Lumpur, Malaysia. Forty randomly selected adults participated (RCT n = 20; Re‐RCT n = 20). The impact their dentition had on the Oral Health Impact Profile‐14 (OHIP‐14) was assessed by calculating the prevalence of oral health impact, and the severity score. Focus group discussions using a semi‐structured guide were arranged through an online meeting platform. Qualitative content analysis identified common themes, and relevant quotes gathered. The impact on OHIP‐14 was limited for both RCT and Re‐RCT groups with no significant differences in the prevalence of oral health impact. Significant differences were found for functional limitation (RCT higher) and psychological discomfort (Re‐RCT higher). Common themes from the discussions include the importance of retaining teeth, the significance of effective communication between clinicians and patients and that the respondents were satisfied with the treatment.

INTRODUCTION

Outcome studies in the field of endodontics focus primarily on clinician‐centred outcomes, such as clinical and radiographic findings, while studies assessing patient‐centred outcomes are relatively sparse [1]. The use of patient‐reported outcomes measures (PROMs) and patient‐reported experience measures (PREMs) to evaluate health services is crucial, as these capture health, well‐being and experiential dimensions directly from the patient's perspective [2]. PROMs capture outcomes such as physical and psychological function, well‐being, severity of symptoms, disability, and impairment [2]. Conversely, PREMs encompass the experience of receiving care, including how and what happened during the encounter [2].

Oral Health‐related Quality of Life (OHRQoL) is a PROM defined as ‘people's perspective on their oral health status including eating, sleeping and engaging in social interaction; their self‐esteem; and their satisfaction with respect to their oral health’ [3]. Previous studies have assessed OHRQoL in endodontics, with various tooth‐level and patient‐level factors influencing this outcome [4]. Among the various instruments available, the Oral Health Impact Profile‐14 (OHIP‐14) is often used to assess the association between endodontics and OHRQoL [4, 5]. OHIP‐14 incorporates the seven conceptual dimensions based on Locker's theoretical model of oral health. These are functional limitations, physical pain, psychological discomfort, physical disability, psychological disability, social disability and handicap [6]. Conversely, PREMs enable investigators to gain insight into the perception of patients towards treatment from a multidimensional view in qualitative studies. These can be explored by conducting focus group discussions to capture in depth a wide range of issues, including patient satisfaction, preferences and adherence to treatment, personal costs and loss of earnings, time required commitments, fulfilment of expectations and decision regrets [4]. Focus group discussion is more cost‐effective in terms of time and resources compared to other qualitative data collection methods. A similar study from the United States used focus group discussion as an adjunct measure, in addition to the OHIP‐14 questionnaire [7]. The qualitative content analysis of extracts from focus group discussions allows the construction of themes that reoccur among the participants to explore their lived experiences [8].

Root canal treatment can be either primary (RCT) or non‐surgical retreatment of an earlier procedure (Re‐RCT). While there are similarities in several steps of these procedures, Re‐RCT requires the additional step of removing various obstructions to the apical terminus, including previous root canal filling materials, and chemical solvents may be required for the latter [9]. Teeth requiring Re‐RCT are categorised as high difficulty technically, and the presence of a previous endodontic treatment may adversely affect treatment outcomes (https://www.aae.org/specialty/wp‐content/uploads/sites/2/2022/01/CaseDifficultyAssessmentFormFINAL2022.pdf).

Previous studies have shown similar tooth survival and periapical health for RCT and Re‐RCT [10, 11, 12, 13]. However, there is a lack of comparison between RCT and Re‐RCT in OHRQoL and PREMs in the currently available studies. Therefore, the aim of the present study was to compare the effect RCT and Re‐RCT have on OHRQoL and PREMs, using OHIP‐14 to calculate the prevalence of oral health impact, and the severity score and patient perception using focus group interviews with qualitative contents analysis, respectively.

MATERIALS AND METHODS

Ethical approval

The study was approved by the International Medical University (IMU) Research & Ethics Committee and designed, conducted, recorded and reported in compliance with the International Conference of Harmonisation/Good Clinical Practice Guidelines (ICH‐GCP). No clinical or radiographic investigation was carried out in this study.

Subject recruitment and inclusion criteria

This retrospective study was carried out in the Oral Health Centre (OHC) of the IMU, Kuala Lumpur, Malaysia. OHC typically serves a diverse range of individuals seeking oral healthcare services, as the centre is accessible to the public with any socio‐economic background. The OHC accepts patients referred by other healthcare professionals, as well as walk‐in patients who request dental care. Charges are applied to patients for the clinical services provided.

This study was conducted from April to December 2020. Subjects who had received RCT and Re‐RCT were randomly selected from the database record. Forty subjects were selected based on calculations using OpenEpi software [14]. The a priori sample size calculation indicated that a sample of 40 was sufficient based on key parameters including study design, desired confidence level (95%) and desired power (80%). The chosen sample size was considered practical given the availability of study participants, as the inclusion criteria specified patients who had received root canal treatment from the same endodontist within a restricted period. The eligibility of the participants was screened based on the predetermined inclusion criteria (received RCT or Re‐RCT having a coronal restoration with at least 6 months in occlusal function; single operator being an endodontist; no other prosthesis (either fixed or removable); age >18 years; American Association of Anesthesiologists physical status classification I or II). Informed consent was obtained from all study subjects prior to their participation. In the RCT group, subjects should have not received root canal treatment in other teeth previously.

Eligible subjects who had completed treatment from 2018 to 2020 were contacted and invited to take part in the study. Out of those invited to participate, five individuals that underwent RCT cited being too busy as their reason for declining. One participant who received Re‐RCT opted not to participate, citing language proficiency concerns, as English was not his/her primary language. Twenty subjects from each treatment group who consented to participate were grouped into three different focus group discussions with different interview dates based on their availability. Interviews were conducted in English through an online meeting via the ZOOM platform. No payment was offered for participation in the study.

Oral health impact profile (quality of life assessment)

The participants completed the English version of the OHIP‐14 questionnaire [5] before the focus group discussion. Participants were asked to rate the impact their root‐treated tooth had on each of the items after treatment based on their experience over the past 6 months. A Likert‐type scale was used; coding 4 as ‘very often’, 3 as ‘fairly often’, 2 as ‘occasionally’, 1 as ‘hardly ever’ and 0 as ‘never’ [15]. Higher OHIP‐14 scores indicate worse and lower scores indicate better OHRQoL [5, 15].

Focus group discussion

All 40 subjects participated in the discussions. A semi‐structured discussion guide (Table 1) was constructed based on a previous similar study [7], and used by the moderator during the discussions. The same moderator conducted all the discussion groups. The discussions were recorded and lasted for 1 h per session and the recordings were used for data collection.

TABLE 1.

The semi‐structured discussion guide constructed for focus group discussions in the present study.

Discussion guide questions
1.	Before you received your root canal treatment (or retreatment), how did you feel about the importance of keeping your teeth?
2.	After you received your root canal treatment (or retreatment), how did you feel about the importance of keeping your teeth?
3.	Why do you consider root canal retreatment instead of extraction?
4.	Before your root canal treatment (or retreatment), how often did you visit the dentist? What was your main reason for visiting the dentist?
5.	After your root canal treatment (or retreatment), how often have you visited the dentist? What has been your main reason for visiting?
6.	What made you go for the root canal treatment (or retreatment)?
7.	How was your experience during the root canal treatment (or retreatment) procedure? Was there any pain? If yes, what was your pain score?
8.	What was your pain score after the procedure? And currently?
9.	Describe your daily life experience since having your root canal treatment (or retreatment)
10.	How does your root canal‐treated (or retreated) tooth feel compared with your other teeth?
11.	How does your root canal‐treated (or retreated) tooth affect your eating or drinking? Does it feel different to eat or drink now?
12.	Does your root canal‐treated (or retreated) tooth affect your appearance and smile? If yes, how has it affected them?
13.	Can you describe any issues or concerns with maintaining root canal‐treated (or retreated) teeth?
14.	If you had to go back for maintenance, how many times and what type of procedures were done?
15.	Are you satisfied with the result of your root canal‐treated (or retreated) tooth? Do you have any issues with your root canal treated (or retreated) tooth currently?
16.	Do you feel that root canal treatment (or retreatment) has improved your quality of life?

Data management and analysis

The OHIP‐14 data were entered into SPSS (IBM SPSS Statistics for Windows, Version 28.0. Armonk, NY, USA) for analysis. Two variables were determined: prevalence of oral health impact, which was calculated by the percentage of participants who answered ‘occasionally’ to ‘very often’ for any of the items, and severity score, which was calculated based on the 14 items' total ordinal value [7]. Shapiro–Wilk normality test was carried out for the mean severity score. Statistical significance of the prevalence scores and the mean levels of the severity scores between groups (RCT vs. Re‐RCT) were calculated using the unpaired t‐test. Descriptive statistics (mean and standard deviation) and frequency counts were calculated for the items and dimensions. The level of significance was set at p = 0.05.

Transcript‐based analysis of the focus group discussion was carried out. The moderators together with an individual unaffiliated with the study transcribed the discussion by listening back to the recorded interviews, and converting the recorded speech into written text. Qualitative content analysis of the transcripts was carried out, and the accuracy of the transcripts was reviewed. Emerging themes and concepts from discussion groups were identified and, when different, compared between the treatment groups. Relevant themes were featured with participants' responses and quotes gathered as examples. Subjects of the selected quotations in the results section were not referenced to protect their anonymity and for confidentiality.

RESULTS

Population characteristics

Forty individuals participated in this study. The RCT group (n = 20) included 17 females and 3 males. On the other hand, the Re‐RCT group (n = 20) included 11 females and 9 males. Their mean age was 47.3 years of age, sub‐divided into decades as follows (n): 18–28 years: RCT:1, Re‐RCT:4; 29–39 years: RCT:7, Re‐RCT:3; 40–50 years: RCT:2, Re‐RCT:3; 51–61 years: RCT:4, Re‐RCT:6; 62–72 years. RCT:5, Re‐RCT:4. There were six anterior teeth and 14 posterior teeth in the RCT group. For the Re‐RCT, there was 1 anterior tooth and 19 posterior teeth.

Oral health impact profile analysis

Distribution of responses to individual items listed in the OHIP‐14 checklist is presented in Tables 2 and 3. Almost all the individuals responded ‘never’ to the items (range across items, 37.5%–87.5%), and only very few individuals responded ‘fairly often’ or ‘very often’. Low OHIP‐14 scores suggested that the treatment addressed the issues previously affecting the participants. The most reported OHRQoL impact experienced was in the psychological discomfort dimension (self‐conscious, 12.5%; felt tense, 10%).

TABLE 2.

Distribution of responses to individual items listed in the OHIP‐14 checklist for the RCT group.

Dimension	Distribution of responses (%)
	Never	Hardly ever	Occasionally	Fairly often	Very often
	(code 0)	(code 1)	(code 2)	(code 3)	(code 4)
Functional limitation
Have you had trouble pronouncing any words?	16 (80%)	3 (15%)	1 (5%)	0	0
Have you felt that your sense of taste has worsened?	14 (70%)	4 (20%)	2 (10%)	0	0
Physical pain
Have you had painful aching in your mouth?	9 (45%)	9 (45%)	2 (10%)	0	0
Have you found it uncomfortable to eat any foods?	8 (40%)	7 (35%)	5 (25%)	0	0
Psychological discomfort
Have you been self‐conscious? Have you felt tense?	8 (40%)	6 (30%)	5 (25%)	1 (5%)	0
	9 (45%)	8 (40%)	3 (15%)	0	0
Physical disability
Has your diet been unsatisfactory?	9 (45%)	8 (40%)	2 (10%)	1 (5%)	0
Have you had to interrupt meals?	11 (55%)	8 (40%)	1 (5%)	0	0
Psychological disability
Have you found it difficult to relax?	10 (50%)	8 (40%)	2 (10%)	0	0
Have you been a bit embarrassed?	11 (55%)	6 (30%)	2 (10%)	1 (5%)	0
Social disability
Have you been a bit irritable with other people?	12 (60%)	8 (40%)	0	0	0
Have you had difficulty doing your usual jobs?	12 (60%)	8 (40%)	0	0	0
Handicap
Have you felt that life in general was less satisfying?	10 (50%)	8 (40%)	2 (10%)	0	0
Have you been totally unable to function?	16 (80%)	4 (20%)	0	0	0

TABLE 3.

Distribution of responses to individual items listed in the OHIP‐14 checklist for the Re‐RCT group.

Dimension	Distribution of responses (%)
	Never	Hardly ever	Occasionally	Fairly often	Very often
	(code 0)	(code 1)	(code 2)	(code 3)	(code 4)
Functional limitation
Have you had trouble pronouncing any words?	19 (95%)	1 (5%)	0	0	0
Have you felt that your sense of taste has worsened?	19 (95%)	1 (5%)	0	0	0
Physical pain
Have you had painful aching in your mouth?	10 (50%)	7 (35%)	3 (15%)	0	0
Have you found it uncomfortable to eat any foods?	10 (50%)	4 (20%)	4 (20%)	2 (10%)	0
Psychological discomfort
Have you been self‐conscious? Have you felt tense?	7 (35%)	4 (20%)	3 (15%)	1 (5%)	5 (25%)
	7 (35%)	4 (20%)	4 (20%)	1 (5%)	4 (20%)
Physical disability
Has your diet been unsatisfactory?	14 (70%)	3 (15%)	3 (15%)	0	0
Have you had to interrupt meals?	12 (60%)	6 (30%)	2 (10%)	0	0
Psychological disability
Have you found it difficult to relax?	9 (45%)	8 (40%)	3 (15%)	0	0
Have you been a bit embarrassed?	10 (50%)	2 (10%)	5 (25%)	2 (10%)	1 (5%)
Social disability
Have you been a bit irritable with other people?	10 (50%)	6 (30%)	2 (10%)	2 (10%)	0
Have you had difficulty doing your usual jobs?	12 (60%)	5 (25%)	2 (10%)	1 (5%)	0
Handicap
Have you felt that life in general was less satisfying?	11 (55%)	5 (25%)	1 (5%)	3 (15%)	0
Have you been totally unable to function?	18 (90%)	2 (10%)	0	0	0

There were no significant differences (p = 0.09) in the prevalence of oral health impact scores between the two groups. However, the prevalence of choosing ‘occasionally (code 2)’ to ‘very often (code 4)’ was higher for Re‐RCT in the majority of the questions. Table 4 illustrates the prevalence of respondents who chose codes 2, 3 or 4 for both groups. Mean severity score was normally distributed (p = 0.07; p > 0.05). There were no significant differences in the mean severity scores between the groups (p = 0.35). Further in‐depth analysis investigating the mean severity score within each of the seven dimensions found significant differences in 2 of the 7 dimensions: functional limitation (p = 0.03; p < 0.05) and psychological discomfort (p = 0.03; p < 0.05) with the RCT group reporting higher score in functional limitation, and Re‐RCT group reporting higher score in psychological discomfort (Table 5). Furthermore, there were significant differences in OHIP question 2 (‘Have you felt that your sense of taste has worsened because of problems with your teeth?’—component of functional limitation) (p = 0.04; p < 0.05) in favour of RCT, and OHIP question 6 (‘Have you felt tense because of problems with your teeth?’—component of psychological discomfort) (p = 0.03; p < 0.05) in favour of Re‐RCT (Table 6). No further significant differences were found.

TABLE 4.

Prevalence of respondents that chose ‘very often’, ‘fairly often’ or ‘occasionally’ for the OHIP‐14 questions for both groups.

Item	RCT (n = 20)	Re‐RCT (n = 20)
Have you had trouble pronouncing any words because of problems with your teeth?	1	0
Have you felt that your sense of taste has worsened because of problems with your teeth?	2	0
Have you had a painful aching in your mouth?	2	3
Have you found it uncomfortable to eat any foods because of problems with your teeth?	5	6
Have you been self‐conscious because of your teeth?	6	9
Have you felt tense because of problems with your teeth?	3	9
Has your diet been unsatisfactory because of problems with your teeth?	3	3
Have you had to interrupt meals because of problems with your teeth?	1	2
Have you found it difficult to relax because of problems with your teeth?	2	3
Have you been a bit irritable with other people because of problems with your teeth?	3	8
Have you been irritable with other people because of problems with your teeth?	0	4
Have you had difficulty doing your usual jobs because of problems with your teeth?	0	3
Have you felt that life in general was less satisfying because of problems with your teeth?	2	4
Have you been totally unable to function because of problems with your teeth?	0	0

TABLE 5.

Mean severity score and comparison between groups across the seven conceptual dimensions based on Locker's theoretical model of oral health.

Conceptual dimension	Severity score
	RCT	Re‐RCT	p‐value
Functional limitation	0.32	0.05	0.02*
Physical pain	0.75	0.77	0.91
Psychological discomfort	0.85	1.6	0.02*
Physical disability	0.62	0.47	0.46
Psychological disability	0.67	0.9	0.31
Social disability	0.4	0.7	0.15
Handicap	0.4	0.45	0.77

^*Significant differences (unpaired t‐test; p < 0.05).

TABLE 6.

Mean severity scores and comparison between groups across the items of the OHIP‐14 questionnaire.

Item	RCT (n = 20)	Re‐RCT (n = 20)	p value
Have you had trouble pronouncing any words because of problems with your teeth?	0.25	0.05	0.14
Have you felt that your sense of taste has worsened because of problems with your teeth?	0.4	0.05	0.03*
Have you had a painful aching in your mouth?	0.65	0.65	>0.99
Have you found it uncomfortable to eat any foods because of problems with your teeth?	0.85	0.90	0.86
Have you been self‐conscious because of your teeth?	1.00	1.65	0.12
Have you felt tense because of problems with your teeth?	0.70	1.55	0.03*
Has your diet been unsatisfactory because of problems with your teeth?	0.75	0.45	0.24
Have you had to interrupt meals because of problems with your teeth?	0.50	0.50	>0.99
Have you found it difficult to relax because of problems with your teeth?	0.60	0.70	0.65
Have you been a bit irritable with other people because of problems with your teeth?	0.65	1.10	0.20
Have you been irritable with other people because of problems with your teeth?	0.40	0.80	0.11
Have you had difficulty doing your usual jobs because of problems with your teeth?	0.40	0.60	0.38
Have you felt that life in general was less satisfying because of problems with your teeth?	0.60	0.80	0.49
Have you been totally unable to function because of problems with your teeth?	0.20	0.10	0.38

Themes from focus discussion groups

Retaining teeth in general

Dental health as part of general health

Thirty‐seven participants did not actively relate dental health as part of general health during the discussion. However, three participants acknowledged the connection between their dental health and their general well‐being. One participant stated that ‘neglecting oral health can affect the general body health too, but unfortunately, not many people are aware of this’. However, all the participants agreed that dental health serves as an indicator of general health after the concept was introduced by the moderator.

All participants strongly emphasised the utmost importance of preserving natural dentition, considering dental extraction a measure of last resort. Additionally, a significant majority of participants from both groups expressed a shared consensus that undergoing RCT or Re‐RCT increased their commitment and appreciation towards retaining their natural teeth.

Several participants from the RCT group expressed a view on the matter. One participant stated, ‘Keeping my own tooth is the priority, I feel that a well‐treated root canal treated tooth can function and perform just as well as a natural (non‐root canal treated) tooth’. And ‘Without a doubt, natural teeth feel better. Having a root‐treated and crowned tooth is always better than having a tooth extracted. Root canal treatment has made my life easier’.

Some participants from both groups expressed a preference for avoiding tooth extraction followed by denture replacement whenever possible, considering the inconveniences associated with wearing removable prostheses. Additionally, some participants highlighted that alternative replacement options such as dental implants were costly and required more extensive intervention compared to the preservation of natural teeth through root canal treatment.

Fear towards extraction

Some participants expressed fear and apprehension towards tooth extraction. Consequently, they perceived root canal treatment as an alternative that enables them to avoid tooth extraction. An example was ‘Heard from my parents that extracting a tooth sometimes can even cause nerve damage in the process, so I always felt it is best to preserve the teeth as much as I can’.

Confidence in the specialist's expertise to save the salvageable tooth

Five participants from the RCT group and 15 participants from the Re‐RCT group expressed that their choice for root canal treatment was due to their confidence in the advice provided by the specialists. One participant from the RCT group stated ‘I had many doubts and questions regarding my tooth prior to the root canal treatment, especially on what would happen and how long it can stay after the root canal treatment. But looking at my condition now, I guess I made the right decision to follow the specialist's suggestion’.

One participant from the Re‐RCT group mentioned ‘I was bothered by the unresolved symptoms after my first root canal treatment. I had some doubts if the pain would fully go away after the retreatment but I'm still quite confident towards root canal treatment and decided to give it another try’.

Understanding of the procedure

Participants in the Re‐RCT group appeared to have a greater understanding of root canal treatment, likely due to their prior experience with it. One participant elaborated, stating ‘It was quite scary to know that the nerves will be removed when I did not have much knowledge back then. However, I was confident and comfortable with it after the dentist provided a thorough explanation of the treatment process’.

Perception of treatment

Minimum to absence of physical pain during the procedure

Most of the participants from both groups described their treatment experience as comfortable and free from pain. However, a small number of participants from the RCT group mentioned experiencing slight discomfort and minor pain. One participant stated ‘There was discomfort and little pain when the dentist was trying to remove the nerve from the tooth I guess’, and ‘There was slight sensitivity when the dentist was drilling, but I do not feel much pain’. In the RCT group, one participant described the experience as ‘a very good, calming, painless, and pleasant procedure’. Several participants acknowledged and highlighted the absence of pain throughout the procedure, attributing it to the administration of injections. One participant stated, ‘There was no pain except during the injection, during which there was slight pain. In fact, I was so at ease during the procedure that I even fell asleep’. Similarly, most participants from the Re‐RCT reported experiencing minimal or no pain during the procedure. Some participants found the retreatment to be more comfortable than the primary treatment, attributing this comfort to the specialist's expertise. One participant expressed a sense of fear during the retreatment due to the difficulties in the removal of the previous crown, which required ‘forceful hard knocks’. However, no pain was reported during the endodontic portion of the process. One participant mentioned, ‘I am pretty afraid of pain, but it was a great experience because other than my fear, it was actually pretty pain‐free. I think the first root canal treatment was slightly more painful, where I remember I could feel slightly more pressure and pain even though it was also performed under local anaesthesia’.

Technology

Participants acknowledged the advantages of advanced technology in improving the comfort and efficacy of the treatment. One participant specifically mentioned the use of enhanced tools during retreatment, highlighting the expertise of the specialist who had undergone 3–4 years of extra training in endodontics. However, a few participants from both groups mentioned that radiographic exposure of intraoral films caused some discomfort.

Length of treatment

A few participants from the RCT group encountered difficulties related to the prolonged duration of keeping their mouths open and the need for multiple visits. One participant remarked, ‘It was a bit difficult to keep my mouth open for a long time, but apart from that, I did not face any difficulties during the treatment’.

Improvement in functionality

Resolving previous signs and symptoms

All participants from the RCT group stated that they underwent treatment due to pain. This treatment eliminated pain in all of the participants, whereas half of them previously reported severe pain with a pain score ranging from 7 to 10. However, 3 out of 20 participants experienced temporary mild discomfort in the few days postoperatively. ‘To be frank, it's not easy to have a toothache, it is a terribly bad experience for me. After the treatment, I felt very relieved and good’. In the Re‐RCT group, all participants opted for retreatment due to signs of root canal infection. Among the participants, eight out of 20 reported pain prior to root canal retreatment. However, following the treatment, all participants were pain free.

Eating, speaking

All participants expressed that their ability to eat and speak significantly improved after undergoing treatment. They expressed the ability to eat comfortably without experiencing any pain. ‘I feel that without the constant irritants, it affects me in a way that makes me more confident, but not really in an aesthetic way. It makes you speak freely and feel comfortable’.

Aesthetic

Most participants from both groups mentioned there were no significant differences in their appearance after undergoing treatment because the affected teeth were located in the posterior region and not readily visible. Participants who received treatment on their anterior teeth observed a positive change in their appearance following the placement of a crown after the endodontic treatment. Two participants who received Re‐RCT on their anterior teeth reported slight tooth discolouration after the procedure. However, they stated that this had a negligible impact on their overall appearance. One participant from the Re‐RCT group mentioned, ‘I'm confident that after the retreatment, the tooth can be retained in the oral cavity for a longer time and contribute to mastication and appearance’.

Comparison with non‐treated natural dentition

Most participants from both groups reported that the teeth feel normal and natural, similar to their non‐treated natural teeth. One participant from the RCT group commented, ‘I don't feel the previous tooth pain and I can eat comfortably. The root canal‐treated tooth feels like a natural tooth, where I can't distinguish between them unless I look into the mirror and try to recall which one’. Similarly, one participant from the Re‐RCT group mentioned, ‘The retreated tooth feels like a normal and healthy tooth. When compared to the primary root canal treatment, the retreatment feels much better because back then I experienced some tingling sensation or pain after the treatment, whereas now there is no pain at all’.

Physical pain/discomfort after treatment

Most participants reported no pain, sensitivity or discomfort following the procedure. However, one participant reported occasional mild discomfort.

Psychological discomfort

Prognosis and longevity

Some of the participants expressed concerns about the potential risk of fracture of the root‐treated tooth in the future if not properly taken care of. They mentioned being very cautious when biting into hard foods due to the perceived brittleness of the teeth. However, a significant number of participants demonstrated an increased focus on maintaining good oral hygiene and protecting their endodontically treated teeth. Participants from the RCT group expressed primary concerns regarding the potential dislodgement of the crown, while participants from the Re‐RCT group were concerned about the possibility of dental caries or reinfection of the tooth in the future.

Maintenance

All participants from both groups demonstrated no concerns regarding the maintenance of the root canal‐treated tooth. Most of the participants from both groups reported improved oral hygiene habits, including flossing and tooth brushing more often. Additionally, they acknowledged the necessity of refraining from chewing hard foods out of apprehension that the root canal‐treated tooth might fracture.

Six participants from the RCT group have changed their dental visit habits from symptom‐driven to attending regular check‐ups, while 7 out of 20 participants still follow a symptom‐driven visiting pattern, and the remainder did not comment on the issue. Statements like ‘I had quite bad dental health previously and I was afraid of visiting a dentist. However, due to my frequent visits to the dentist, I am no longer afraid of the dentist anymore’. And ‘I hardly visited a dentist unless I have pain. However, after the root canal treatment, I started to visit a dentist once every six months, and I also make sure my children visit the dentist once a year as well’ were made. Most respondents stated that their follow‐up visits primarily involved check‐ups and regular cleanings. Several patients also mentioned that their follow‐up visits were intended for the placement or maintenance of permanent coronal restorations.

Satisfaction

All participants from both groups were satisfied and pleased with the outcome of endodontic treatment with no issues as it eliminated their pain, and they were able to enjoy eating like before. All participants reached a consensus that they would highly recommend root canal treatment and retreatment done by qualified professionals to individuals in need.

DISCUSSION

This study compared the OHRQoL and experiences of subjects who received RCT and Re‐RCT, and highlight the role of patient perceptions in the decision‐making process based on a combined quantitative‐qualitative methodology (OHIP‐14 questionnaire and focus group discussion) to gain a deeper understanding of the phenomena under study. The groups had similar overall OHIP scores with limited impact on OHRQoL. The RCT group reported a higher severity score in functional limitation, while the Re‐RCT group reported a higher severity score in psychological discomfort. Several main themes from the qualitative analysis were in common in both groups, including the importance of retaining their teeth in association with symptom resolution, and the role of communication in patient satisfaction. Different responses in the theme of psychological discomfort were likely related to the fact that the Re‐RCT had past experience of failed RCT.

RCT patients who experienced for the first time the treatment and the placement of a coronal restoration, such as a crown, related to a feeling of unfamiliarity and the feeling of a different sensation. For instance, some patients expressed sensations of having an artificial foreign body present in their mouth, or they had a constant concern about potential crown dislodgement, leading them to avoid biting on hard substances. Conversely, the Re‐RCT group experienced primary treatment failure. As a result, some expressed concerns and fears regarding the potential for further failure and possible tooth loss. In addition, Re‐RCT cases are commonly more complex, thus requiring additional time and cost. Negative views were typically temporary, with most patients reporting a gradual return to normality over time. Overall, respondents expressed satisfaction with treatment outcomes, including pain resolution and improvement in various aspects of their lifestyle in terms of function, speech, eating and aesthetics. Both groups agreed that root canal treatment should be the option of choice aiming to save the tooth instead of tooth extraction and implant placement provided treatment is a viable option.

The distinction between items component of the OHIP is considered subtle, including functional limitation and psychological discomfort [5, 6]. The OHIP‐14 questionnaire was selected to investigate social impact due to its global nature, succinctness, reliability and validity, plus previous application in endodontology [5, 7, 15]. Nonetheless, a limitation of OHIP‐14 is that it comprises closed‐ended questions which restrict respondents from freely expressing their thoughts and experiences. Therefore, focus group discussions enhanced the study by providing qualitative insights that complement the quantitative data obtained from the questionnaire. Qualitative content analysis has been used in endodontology to explore the perception of qualitative data in further detail [7, 16, 17, 18, 19]. The qualitative result from the focus group discussion using semi‐structured interviews is a strength of this study because it enables practitioners to gain an insight into the respondents' perception towards treatment leading to better care, as practitioners can explore the subject area from a multidimensional standpoint, considering that the patient's views are decisive during the shared decision‐making process [20]. Semi‐structured interviews are commonly used in healthcare and provide both guidance on the dialogue and flexibility to discuss issues not considered a priori by the researchers but that are important for the group [20]. Focus group discussions were held via Zoom due to its convenience and the restrictions related to the COVID‐19 pandemic that limited face‐to‐face interactions.

The study presented some limitations. The retrospective design is associated with recall bias, as respondents had to rely on their memory to recollect past experiences when responding to questions in the focus group discussion. Nevertheless, the use of previously validated tools and a structured interview limit this issue [21], although the OHIP‐14 tool was originally designed to assess broad oral diseases [5]. In the absence of ‘before and after’ treatment interviews, the impact on the outcomes (OHRQoL and PREMs) and interventions (RCT vs. Re‐RCT) may not be assessable [22]. In addition, the findings are representative of the setting and may have limited external validity, as factors such as socio‐economic status may affect PROMs and PREMs [23, 24], and also may have been affected by the COVID‐19 pandemic. However, they improve the understanding of the overall association between patient‐centred outcomes and endodontics locally and globally, the latter when taken into account with other comparable studies, also considering the paucity of evidence regarding PROMs and PREMs in endodontics originating from the Asia‐Pacific region. Confounding factors have an impact on OHRQoL, including further oral dental health issues and their management (e.g. provision of restorations) [25], and subject‐level factors, though previous studies reported inconsistent findings for age groups and gender, among others [24, 26, 27]. The exclusion criteria applied during the selection process (only one tooth has received root canal treatment, restored and functional for <6 months, and no other prostheses present) aimed to diminish these intra‐oral confounding factors or operator‐related factors (one endodontist treated all the participants). Regarding tooth‐level factors, the RCT included more anterior teeth than the Re‐RCT group in the present study. Root canal treatment on anterior teeth has a more profound (positive) impact on OHRQoL [24], and teeth with more complex morphology (e.g., molars) require Re‐RCT more commonly [28], which can help to explain the composition of this study group. Patient's perceptions may vary depending on the tooth group undergoing treatment. All tooth groups were included in the study as from a clinical perspective, endodontic intervention may be necessary for any tooth and patient experiences may vary widely based on individual factors irrespective of the tooth type. Therefore, including all tooth groups ensures a broader understanding of treatment outcomes and patient experiences across scenarios. For instance, anterior teeth being more visible and aesthetically significant may raise concerns about appearance for patients. Conversely, posterior teeth are often associated with functional considerations such as chewing ability. Therefore, by including all tooth groups, researchers can explore potential variations in patient perceptions and priorities when addressing treatment outcomes. Regarding focus group discussion, what is important is the interaction, rather than the number of participants or its composition [20]. Notably, participants were selected as previously described.

The preoperative status of a tooth before root canal treatment may affect OHRQoL, in particular, the presence of pain [4, 28]. In the present study subjects with non‐previously treated teeth were compared to those receiving retreatment, and significant differences were found in two OHIP‐14 dimensions related to impairment of the individual, namely functional limitation (RCT lower OHRQoL) and psychological discomfort (Re‐RCT lower OHRQoL). While most of the respondents of the RCT group reported pain during the group discussion, endodontic retreatment is commonly prompted by symptoms (i.e., tenderness, pain or swelling) [26]. This is consistent with the Re‐RCT group in the present study, and a previous study from the United States [18], as signs of root canal infection prompted the treatment, although exceptions occur [18]. Overall, it is difficult to reach a definitive conclusion on the role of a specific intraoperative step (including the removal of previous root canal filling in the present study) on OHRQoL [4].

The qualitative findings of the present study are in agreement with similar studies from other geographic areas and settings [7, 16, 17, 18, 19, 29], though there is a paucity of qualitative studies on patients' perceptions in endodontology. Several collective views from the focus group discussion in the present study generated topics that are in common with previous qualitative studies in the field [e.g. ‘perception of the treatment and its outcome’ [29], ‘follow‐up dental visits’ [7, 17], ‘pain associated with treatment’ [17], ‘treatment failure concerns’ [17], ‘treatment weakened teeth’ [18]. Conversely, the theme ‘cost/financial implication’ did not emerge as a main theme in the present study, but it was considered relevant in studies based in a University clinic from the United States [7], or in specialist private practices in Western Australia [17]. The latter supports the role of the setting regarding PREMs.

Effective communication and patient‐centred care have a crucial impact on patient satisfaction, as their perception of treatment is enhanced [16, 30]. By providing comprehensive information and educating patients about the procedure, operators can effectively alleviate patients' anxiety, enhance their understanding and improve their perception of endodontic treatment. For example, some patients in the Re‐RCT group expressed fear regarding the removal of the crown during the procedure, despite the absence of pain. Factors such as patient rapport and attentiveness can hold greater value in the eyes of patients than the clinician's technical proficiency [30]. Confidence in receiving advice and treatment from a specialist has been reported previously [17].

Future studies in endodontology should consider PREMs and PROMS in conjunction with clinical data, since the assessment of oral health should embrace both categories in unison [5, 6]. Multicentre studies with before and after evaluations are required to understand the impact of the possible patient‐related, tooth‐related and setting‐related factors on PREMS and PROMs. In addition, it would be desirable to explore participants' perspectives regarding their willingness to undergo retreatment again as well as any other further treatment (e.g., replacement of extra‐coronal restorations) and in the event of a subsequent failure of Re‐RCT. Finally, the development of an OHRQoL measurement instrument for endodontology should also be considered [23].

CONCLUSIONS

RCT and Re‐RCT presented with limited impact and overall similar OHRQoL, except in two dimensions; the RCT group presented a higher severity score in functional limitation, while the Re‐RCT group reported a higher severity score in psychological discomfort. Several themes from the qualitative analysis were in common, including the importance of retaining their teeth, symptom resolution and the role of communication in patient satisfaction. Minor differences in psychological discomfort were likely associated with the fact that the RCT group had not experienced root canal treatment previously.

AUTHOR CONTRIBUTIONS

Eileen Yi Ning Lee: Conception and design, acquisition of data, analysis and interpretation of data and manuscript writing (first draft). Shekhar Bhatia: Conception and design, acquisition of data, analysis and interpretation of data, manuscript writing (first draft) and final approval of the version to be published. Shivani Kohli: Conception and design, acquisition of data, analysis and interpretation of data and manuscript writing (first draft). Giampiero Rossi‐Fedele: Analysis and interpretation of data, manuscript writing and final approval of the version to be published. Esma J. Doğramacı: Analysis and interpretation of data, manuscript writing and final approval of the version to be published. Venkateshbabu Nagendrababu: Conception and design, analysis and interpretation of data, manuscript writing and final approval of the version to be published.

FUNDING INFORMATION

This study was supported by an Institution Grant from the International Medical University (BDS 1‐01/2020).

CONFLICT OF INTEREST STATEMENT

The authors deny any conflict of interest.

Lee EYN, Sua ZY, Bhatia S, Kohli S, Rossi‐Fedele G, Doğramacı EJ, et al. Oral health‐related quality of life and perceptions of patients following primary root canal treatment or non‐surgical retreatment. Aust Endod J. 2024;50:559–570. 10.1111/aej.12868