Associations of number and position of tooth loss and quality of life in the Chilean population: a cross-sectional study

Abstract

Background

Multiple studies have demonstrated the association between Quality of Life (QoL) and the prevalence of caries, periodontitis, and tooth loss. However, the role of the position and location of tooth loss in impacting QoL remains unclear.

Aim

To evaluate the association of tooth loss, including anterior losses, with Health-Related Quality of Life (HRQoL) and Oral Health-Related Quality of Life (OHRQoL) in Chileans aged 15 years and older who participated in the ENS 2016–2017.

Methods

In this cross-sectional study we included 5473 individuals enrolled in the last Chilean National Health Survey (ENS 2016–2017). HRQoL was measured using the EQ-5D questionnaire, while OHRQoL was assessed through a general question (GQ/ENS) and five specific questions (SQ/ENS). An analysis of variance test was performed to determine how difference or variation in the number(s) of teeth affected their HRQoL. Odds ratios with corresponding 95% confidence intervals were calculated using multinomial logistic regression to determine how and to what degree anterior tooth loss was associated both with HRQOL and OHRQOL in the study sample.

Results

The number of remaining teeth was significantly higher in the ‘No problems’ group across all EQ-5D dimensions, except Anxiety/Depression. The largest difference was in Self-care, where ‘No problems’ had a mean of 20.18 compared to 6.43 teeth in the ‘Problematic’ group. Anxiety/Depression showed higher odds of ‘Some problems’ with upper anterior tooth loss, while ‘Usual Activities’ showed higher odds of ‘problematic’ with lower anterior tooth loss. Participants with an ‘Excellent’ OHRQoL perception had a mean of 24.32 teeth. Also, upper and lower anterior tooth loss increased the odds of OHRQoL self-perception.

Conclusions

Tooth loss was associated with lower HRQoL and OHRQoL in some groups, with more remaining teeth associated with better outcomes, while anterior tooth loss was- linked to worse self-perceived oral health.

Background

The World Health Organization (WHO) defines quality of life (QoL) as an individual’s perception of their position in life within the context of the culture and value systems in which they live and in relation to their goals, expectations, standards, and concerns [1]. Health-related quality of life (HRQoL) links these subjective assessments with various aspects of health by encompassing physical, psychological, and social dimensions that directly affect overall well‑being [2]. This multidimensional construct is indispensable in both clinical practice and research, as it facilitates the identification of patient needs and improves communication between patients and healthcare professionals [3].

Recent advances in HRQoL research have focused on refining measurement approaches that capture not only classical aspects of health status but also nuanced dimensions—such as functional capacity and social participation—that are particularly relevant in the context of chronic diseases and rehabilitative care [4, 5]. Modern instruments are increasingly evaluated with updated psychometric methodologies that ensure both responsiveness and cross‑cultural validity [6]. In addition, recent systematic reviews emphasize the importance of understanding what these questionnaires measure—specifically the impact on physical functioning, emotional state, and social engagement—rather than simply listing the instruments themselves [7].

Within oral health research, the concept of oral health‑related quality of life (OHRQoL) has emerged as an indicator of how oral conditions affect daily functioning and psychosocial well‑being [8]. Rather than focusing solely on traditional clinical parameters, OHRQoL instruments capture the patient’s subjective experience of oral health, including issues related to pain, aesthetics, and functional limitations. Emerging evidence indicates that missing teeth’ number and intraoral position substantially influence the overall quality of life [9,10,11,12]. For example, several studies have reported that anterior tooth loss may disproportionately affect emotional and social dimensions, thereby intensifying the negative impact on perceived quality of life [13, 14].

Recent World Bank data shows Chile’s socioeconomic indicators reflect significant improvements over the past decades. For example, Chile’s GDP per capita in current US dollars reached approximately US$17,000 in 2023, while the country’s gross enrollment ratio for secondary education is 106%. In addition, the infant mortality rate in Chile has declined substantially, with recent figures showing around five deaths per 1,000 live births. Per capita income has also steadily increased over time, supporting a growing standard of living. These improvements in economic and social indicators provide a context for interpreting health outcomes in quality of life among the Chilean population [15]. In Chile, the last National Health Survey (ENS 2016–2017) is notable for being the first epidemiological instrument to include the measurement of anterior tooth loss. Although this survey provides a rich dataset of 5,473 participants, previous analyses have focused mainly on older adults, leaving a gap in research that encompasses the entire adult population [16].

The aim of the present study was to evaluate the association between tooth loss—including anterior losses—with HRQoL and OHRQoL in Chileans aged 15 years and older who participated in ENS 2016–2017. We hypothesized that a reduction in the number of remaining teeth, particularly in the anterior region, is associated with lower HRQoL scores and a more pronounced negative impact on OHRQoL.

Methods

Study design and setting

We conducted a cross‑sectional study using data from the 2016–2017 Chilean National Health Survey (ENS) administered by the Ministry of Health (MINSAL) to assess the health status of the national population. The survey employs a complex multistage probability sampling design and collects data on health status, self‑perceived oral health, demographic characteristics, and clinical oral examinations [16]. The analysis included all individuals with no dropouts. This study was nested in the ENS 2016–2017, with protocols and written informed consent approved by the Scientific Ethics Committee of the Faculty of Medicine of Pontificia Universidad Católica de Chile (CEC-MedUC, Project number 16–019).

Participants and inclusion criteria

Participants were selected in accordance with the ENS 2016–2017 protocol. Inclusion criteria required that individuals be Chilean residents who provided complete data on health, demographic, and oral health components. Exclusion criteria included incomplete responses on key variables and conditions that precluded a proper clinical oral examination (e.g., severe dental pain or trauma).

Oral health assessment

Intra‑oral examinations followed World Health Organization (WHO) diagnostic standards [17]. Examinations were performed by a team of nurses trained and calibrated by nine dentists affiliated with MINSAL. The oral health examination was performed as part of the ENS 2016–2017 at-home visits using a dental mirror, dental explorer, and standard operation lamp. According to the pilot study of the ENS (n = 105 subjects), which evaluated the validity and reliability of the measurements taken by seven nurses against the diagnosis made by the dentist, sensitivity to detect missing teeth and dental fillings was 70%, when compared to the diagnosis by the dentist [16]. The inter-examiner reliability was substantial (kappa value of 0.75, p-value < 0,001) according to the criteria proposed by Landis and Koch [18]. The intra-examiner reliability was not measured at the end of the nurse calibration process. A detailed manual standardized the evaluation, which focused on three aspects per dental arch: (i) the use of removable prostheses, (ii) the total number of remaining teeth (recorded as a continuous variable), and (iii) anterior tooth loss. Anterior tooth loss was defined dichotomously as “yes” if at least one of the six anterior teeth was missing, and “no” otherwise. Although further differentiation (e.g., single versus multiple anterior tooth losses or losses due to other reasons besides dental caries) could have provided additional insight, the available data permitted only a dichotomous classification. Clinical examinations were performed with patients seated under headlamp illumination. Participants were instructed to brush their teeth and remove any removable prostheses before the examination, and data were recorded electronically following ENS 2016–2017 protocols. Patients presenting with severe dental pain, trauma, suppuration, facial swelling, or post‑extraction bleeding were referred to an emergency dental care center.

Quality of life assessment

Quality of life was evaluated using two instruments. Health‑related quality of life (HRQoL) was measured with the EQ‑5D, a generic and validated instrument that assesses five dimensions—mobility, self‑care, usual activities, pain/discomfort, and anxiety/depression—each with three response levels [19]. Data for the EQ‑5D were collected by trained interviewers using standardized procedures. Oral health‑related quality of life (OHRQoL) was assessed via a general question— “How would you describe your oral health?”—with responses ranging from “excellent” to “very poor,” and five specific questions addressing issues such as discomfort during speech or eating, pain, and interference with daily activities and social relationships. These questions were answered on a five‑point Likert scale (never, rarely, sometimes, very often, always). The OHRQoL component of the ENS comprises questions developed through a consensus process by a panel of five experts appointed by the Chilean Ministry of Health for the initial version of the ENS in 2003. These five questions have since been consistently included in the three Chilean National Health Surveys (ENS 2003, ENS 2009–2010, and ENS 2016–2017), thereby ensuring continuity and reinforcing their face and content validity as measures of oral health-related quality of life in the Chilean population [16].

Confounding variables and data collection

Demographic and socioeconomic variables—including age, sex, geographical area (urban/rural), and educational level (low, medium, or high)—were collected using standardized self‑report questionnaires [16]. These confounders were incorporated into the statistical analyses to adjust for potential biases.

Statistical analysis

Analyses were conducted using the complex sampling module in SPSS version 24.0 (Mac OS X; SPSS Inc., Chicago, IL, USA). Means and proportions, along with their standard errors (SE) and 95% confidence intervals (CI), were estimated using the Taylor linearization method. The dependent variables were HRQoL (measured by the EQ‑5D) and OHRQoL (measured by the general and specific ENS questions). Independent variables included the total number of remaining teeth (continuous) and anterior tooth loss (yes/no). We used the number of remaining teeth as a proxy for tooth loss, thereby capturing both quantitative and qualitative aspects of dental status. An analysis of variance (ANOVA) was performed to assess associations between the number of remaining teeth and QoL scores, and multinomial logistic regression with stepwise selection was used to determine odds ratios (OR) for QoL outcomes based on anterior tooth loss, adjusting for age, sex, geographical area, and educational level.

Results

The study included 5,473 individuals aged 15 to 98, representing the whole country. The mean age of the study population was 43.2 years (SE = 0.4), with females representing 63.4% of the sample and exhibiting a mean age of 43.9 years (SE = 0.5). The overall mean number of remaining teeth was 20.2 (SE = 0.2) for women and 21.5 (SE = 0.3) for men. Anterior tooth loss was more prevalent in the maxilla (40.7%, 95% CI: 39.4–42.0%) than in the mandible (27.5%, 95% CI: 26.3–28.7%), with higher rates observed among females in both arches (Table 1).

Table 1 Study population characteristics (n = 5473), all participants of the third Chilean National health survey (ENS 2016–2017)

Analysis of HRQoL, as measured by the EQ‑5D, revealed that the number of remaining teeth was significantly higher among participants classified in the “No problems” group (G1) than among those in the “Some problems” (G2) and “Problematic” (G3) groups across all dimensions except anxiety/depression (D5). The higher difference was observed in the Self‑care dimension, where the mean number of remaining teeth was 20.18 in G1 compared with 6.43 in G3. In the Anxiety/Depression dimension, upper anterior tooth loss was associated with increased odds of being classified in G2 (OR = 1.48, 95% CI: 1.10–1.97), whereas for the Usual Activities dimension, lower anterior tooth loss was associated with higher odds of classification in G3 (OR = 2.35, 95% CI: 1.11–4.94) (Table 2).

Table 2 Association between the number of remaining teeth, including anterior tooth loss, and HRQoL, according to the EQ-5D questionnaire

For OHRQoL, there was a clear association between the number of remaining teeth and self‑perceived oral health. Participants reporting “Excellent” oral health had an average of 24.32 remaining teeth (SD = 0.62), while those reporting “Very poor” oral health had an average of 12.88 remaining teeth (SD = 0.97). Furthermore, the absence of teeth in the maxilla was associated with higher odds of a negative oral health perception compared with tooth loss in the mandible (Table 3).

Table 3 Association between the number of remaining teeth, including anterior tooth loss, and OHRQoL, according to GQ/ENS

Analysis based on the five specific OHRQoL questions (SQ/ENS) demonstrated that, for all items except Q2, the number of remaining teeth was significantly higher in the “Never” group (better OHRQoL) compared to the other response categories, with a continuous decline observed as the frequency of problems increased. For Q1, both upper and lower anterior tooth loss were significantly associated with increased odds of reporting “Sometimes” or worse outcomes (poor OHRQoL). For Q2, only upper anterior tooth loss was related to higher odds of responding “Often.” For Q3, the presence of both upper and lower anterior tooth loss was significantly associated with increased odds of answering “Always” (poor OHRQoL). Similar associations were observed for Q4 and Q5, with anterior tooth loss associated with increased odds of responses indicative of poorer oral health (Table 4).

Table 4 Association between the number of remaining teeth, including anterior tooth loss, and OHRQoL according to SQ/ENS

Discussion

The present study evaluated the impact of both the number and the intraoral position of tooth loss on health‑related quality of life (HRQoL) and oral health‑related quality of life (OHRQoL) using data from the 2016–2017 Chilean National Health Survey. A clear association was observed between a lower number of remaining teeth and poor HRQoL across the five dimensions of the EQ‑5D, with the Self‑care dimension exhibiting the higher difference. Similarly, tooth loss was consistently associated with poorer self‑perceived OHRQoL. Both upper and lower tooth loss were associated with a decline in OHRQoL scores, although the relationship with HRQoL was less consistent.

Our findings regarding HRQoL are consistent with previous reports that show a significant association between a lower number of remaining teeth and poor HRQoL [20, 21]. However, contrasting evidence exists; some studies have failed to detect a positive association in certain dimensions—such as pain/discomfort and anxiety/depression [22]—highlighting the complexity of measuring subjective health outcomes. In the current study, a substantial decrease in the number of teeth was observed when moving from the “no problems” to the “problematic” level of HRQoL in the EQ‑5D dimensions. These results suggest that tooth loss may impair various aspects of daily functioning, particularly self‑care [11].

OHRQoL was found to be strongly influenced by the quantitative loss of teeth. A lower number of remaining teeth was associated with poorer self‑perceived oral health, which can be explained by the detrimental effects of tooth loss on masticatory function, phonetics, and aesthetics [13]. The role of functional capacity in determining OHRQoL has been supported by previous studies reporting that diminished chewing and speech capabilities adversely affect overall satisfaction with oral health [23,24,25]. Moreover, this study is the first in Chile to demonstrate that the loss of anterior teeth—especially in the maxilla—negatively impacts oral health perception more than tooth loss in the mandible. Such findings underscore the need to assess the quantity and position of missing teeth when evaluating their effect on quality of life.

The use of generic instruments, such as the EQ‑5D, offers the advantage of enabling comparisons across different systemic conditions and evaluating the impact of comorbidity on HRQoL [26]. Nevertheless, generic measures may lack the sensitivity required to detect subtle differences between specific oral health conditions [27, 28]. Studies comparing generic and condition‑specific instruments, such as those employing the OHIP‑14, have demonstrated that only the condition‑specific tools are sensitive enough to detect nuanced impacts on quality of life, particularly in cases of facial deformities or aesthetic concerns [29]. In the context of a national health survey, however, the incorporation of a generic instrument is justified, given the need for broad population‑level assessments [30].

This study’s inclusion of participants aged 15 years and older extends the focus beyond older adults, who have been the primary subjects in many previous investigations [31, 32]. While older individuals may sometimes report paradoxically better subjective oral health due to adaptive perceptions [33], the proportion (24.3%) of participants aged 65 or older in the present sample likely minimizes this bias.

Several limitations merit consideration. The cross‑sectional design precludes causal inferences, and using a dichotomous measure for anterior tooth loss restricts the ability to differentiate between single and multiple tooth losses. In addition, tooth loss was measured solely by the number of remaining teeth without accounting for the underlying aetiology, and the OHRQoL questionnaire combined the assessment of teeth and prostheses, potentially confounding responses. Finally, although a calibrated nursing team performed the oral examinations, examinations conducted by dentists represent the gold standard. Finally, the presence of residual confounding due to unmeasured or unidentified confounding variables could be affecting the present study.

Despite these limitations, the study contributes novel evidence from a large, nationally representative dataset regarding the dual impact of tooth loss on both HRQoL and OHRQoL. The results highlight the importance of considering both the quantitative (number of remaining teeth) and qualitative (position of missing teeth) aspects in evaluating the influence of oral health on quality of life. These findings have implications for designing targeted dental health interventions and public health strategies aimed at improving overall well‑being.

Conclusion

Our study suggests that a lower number of remaining teeth is significantly associated with decreased HRQoL and OHRQoL in Chilean individuals aged 15 years and older. Anterior tooth loss—especially in the maxilla—exerts a disproportionately negative effect on self‑perceived oral health. These findings underscore the necessity of incorporating both the quantitative and positional aspects of tooth loss into future research and public health initiatives. Further longitudinal studies employing refined, validated instruments are warranted to elucidate the causal pathways between oral health and quality of life and to inform effective dental health interventions.