Relationship Between Orthodontic Treatment Need, Dental Caries Experience, and Oral Health-Related Quality of Life Among Patients Seeking Dental Care: A Cross-Sectional Analytical Study

Oral health disorders such as malocclusion, dental caries, and oral health-related quality of life (OHRQoL) are among the most common oral health disorders worldwide and a significant public health burden.[1][2] Malocclusion is the third most frequently reported oral disorder following dental caries and periodontal disease, and has been reported to occur in between 39% and 93% of different populations.[3] These conditions have additional implications beyond their functional deficits, such as an impact on appearance, social functioning, and quality of life.

 Patients coming to the dentist may have varying levels of orthodontic treatment need and dental caries experience, which can influence, or both.[4] The Index of ‘Orthodontic Treatment Need’ (IOTN) is a commonly used index to assess orthodontic treatment need, while the ‘‘Decayed, Missing, and Filled Teeth’ ’ (DMFT) index is used to assess dental caries experience.[5, 6]

 OHRQoL is a patient-centred measure of the functional, psychological and social impacts of oral diseases and is typically measured using an established instrument, like the ‘Oral Health Impact Profile’ (OHIP-14).[7] Previous studies have examined the relationship between need for orthodontic treatment and OHRQoL or between dental caries experience and OHRQoL.[8] A knowledge of these interrelationships is necessary to recognize those patients who require a more intensive treatment program and to prioritize the need for comprehensive patient-centred oral care.[9]

 Hence, the objective of this study was to find out the relationship between orthodontic treatment needs, dental caries experience and OHRQoL among individuals attending dental services. The results could serve as evidence for implementing integrated preventive and therapeutic strategies, help identify subjects who are at risk of developing poor oral health outcomes at an early stage, and support clinical decision-making and resource allocation in routine dental practice.

A total of 136 patients participated in the study. Participants' mean age was 28.9 years ± 8.4 years, most of them aged between 18 and 25 (39.7%). 57.4% of the study population were females. The majority of the participants were graduates (41.9%) and employed (43.4%). (Table 1)

 In terms of clinical features, 38.2% of the subjects had definite orthodontic treatment need (IOTN Grade 4-5) and 33.1% of the subjects had borderline orthodontic treatment need. The mean DMFT score was 4.72 ± 2.51, and the mean OHIP-14 score was 18.63 ± 8.92. Both DMFT and OHIP-14 were assessed for normality and it was found that they were not normally distributed. (Table 2)

 There was a significant positive correlation between orthodontic treatment need and OHIP-14 score (ρ = 0.612, p < 0.001). The dental caries experience was also positively associated with the OHIP-14 score (ρ = 0.471, p < 0.001). Besides, there was a moderate positive correlation between orthodontic treatment need and DMFT score (p < 0.001). (Table 3)

 The mean DMFT and OHIP-14 scores were significantly higher for participants with higher orthodontic treatment needs. The mean DMFT score was 3.2 ± 1.8 in the little or no treatment need group and 6.0 ± 2.6 in the definite treatment need group. The mean OHIP-14 score was also found to be significantly higher across IOTN categories (p < 0.001 for both comparisons). No differences between demographic (DMFT) or functional (OHIP-14) scores were seen for males and females. (Tables 4 and 5)

 After controlling for age, gender, and educational level, multiple linear regression analysis revealed that orthodontic treatment need (p < 0.001) and DMFT score (p < 0.001) were the independent predictors of poorer oral health-related quality of life. The regression model explained 54.1% of the variance in OHIP-14 scores (p < 0.001). (Table 6).

Table 1. Sociodemographic Characteristics of the Study Participants (n = 136)

Table 2. Clinical Characteristics and Normality Assessment of the Study Variables (n = 136)

 Table 3. Correlation between Orthodontic Treatment Need, Dental Caries Experience and Oral Health-Related Quality of Life

 Table 4. Comparison of Mean DMFT and OHIP-14 Scores Across Orthodontic Treatment Need Categories

 Table 5. Comparison of DMFT and OHIP-14 Scores According to Gender

 Table 6. Multiple Linear Regression Analysis for Predictors of Oral Health-Related Quality of Life

The results of the present study showed that a higher orthodontic treatment need was significantly related to higher DMFT scores and decreased OHRQoL. Second, a lower OHRQoL was predicted by orthodontic treatment need and dental caries experience, after adjustment for potential confounding variables. The results indicated that both malocclusion and dental disease combined affect the patients' functional, psychological, and social health.

 In the current investigation, there were 38.2% with definite orthodontic treatment need. The prevalence rate did not differ significantly between our results and those reported by Pereira et al. (2021), who found a high percentage of patients that needed orthodontic intervention among those seeking orthodontic treatment.[15] Further, Bekes et al. (2023) concluded that clinically significant orthodontic treatment need was prevalent in the study population, which has led to increased need for orthodontic services.[4]

 In our study, the mean DMFT score was found to be 4.72 ± 2.51, which was a moderate burden of dental caries among the subjects. This result is compatible with several recent studies that found that those who sought orthodontic consultation had a greater caries experience, and that those who did not go to the dentist regularly or had poor oral hygiene had higher DMFT scores. Similarly, research across various populations has shown that untreated dental caries is a significant problem in young adults receiving comprehensive dental care and can impact treatment outcomes and patient satisfaction.[15]

 In our study, participants with a higher IOTN had significantly worse OHQOL as evidenced by the OHIP-14 scores, which were progressively higher in the IOTN categories. The results are consistent with Pereira et al. (2021), who found a higher prevalence of poor OHRQoL in patients needing orthodontic treatment, but a greater impact on OHRQoL for tooth loss was found in their regression model.[11] Similarly, Bekes et al. (2023) showed that there was increased impairment in OHRQoL among children when the need for orthodontic treatment increased.[4]

 In the present study, the orthodontic treatment need was significantly associated with the OHIP-14 score, as a strong positive correlation was noted (ρ = 0.612). This is also what was found in the recent multicenter cohort study by Keß et al. (2026), which reported that higher orthodontic treatment need and certain anterior malocclusions significantly negatively affected multiple domains of OHRQoL. Similarly, a cross-sectional study of adults with less severe malocclusion in 2024 assessed OHRQoL and noted that patients with higher levels of subjective OOTN had significantly poorer OHRQoL, even with relatively mild clinical malocclusion, emphasising the need to consider patient perception as well as clinical assessment.[16]

 The current study also revealed a strong positive correlation between the dental caries experience and the OHRQoL. Patients with higher DMFT had significantly poorer OHIP-14 scores, indicating that untreated caries significantly affects functional impairments, pain, and psychological discomfort. The findings are also in line with recent studies that found that higher caries experience was associated with poorer eating ability, social function, and oral health perception, leading to poorer quality of life.[17, 18]

 Another interesting result of our study was the moderate positive correlation between the need for orthodontic treatment and the DMFT score. The presence of greater malocclusion was associated with greater caries experience, perhaps because of the buildup of plaque as a result of dental crowding and oral hygiene problems. These associations have also been reported in recent studies, indicating that extreme malocclusion may be associated with increased caries risk and underscoring the importance of providing comprehensive preventive and orthodontic services.[19, 20] .

 In our study, there were no statistically significant differences in OHIP-14 or DMFT scores between males and females. Similar results have been noted in other recent studies in which gender was not found to be a separate factor influencing the development of OHRQoL. when calculated independently of clinical factors. Conversely, Pereira et al. (2021) found better OHRQoL for men than for females, showing that there are population, psychosocial, and cultural differences that could explain the varied results across studies.

 Multiple linear regression analysis showed that the need for orthodontic treatment and DMFT score were independent factors that affected poorer OHRQoL, while age, gender, and educational status did not significantly influence the oral health-related quality of life. These results corroborate the study of Pereira et al. (2021), who used multivariable regression and had similar findings that objective oral health conditions accounted for much of the variance in OHRQoL.[15] In a similar way, Keß et al. (2026) found that the orthodontic treatment need was an independent factor for several QOL domains after adjusting for confounding factors.[21]

 In general, the results of the present study are consistent with the increasing evidence that shows orthodontic treatment need and dental caries are associated, and they can have a substantial impact on the oral health-related quality of life. In our study, we add additional evidence by simultaneously assessing these variables in the same analytical model in dental care seekers. The results reinforce the need for a holistic oral evaluation, timely orthodontic referral, and preventative caries management to optimize outcomes for patients and enhance their quality of life.

 The following are some limitations of this study. First, the cross-sectional design did not allow for establishing a causal relationship between orthodontic treatment need, dental caries experience, and oral health-related quality of life. Second, the study was a non-probability consecutive sampling of a single tertiary care center, and this might restrict the generalizability of the results to the broader population. Thirdly, the measure of oral health-related quality of life was measured by a self-reported instrument, which could have introduced a recall and/or social desirability bias. Lastly, other variables that could affect the oral health-related quality of life, including socioeconomic status, periodontal health, oral hygiene practices, and dietary habits, were not assessed.

Among dental care seekers, there was a significant relationship between oral health-related quality of life and orthodontic treatment need or dental caries experience. People who required more orthodontic treatment tended to have higher DMFT scores and more significant OHRQoL impairment. Orthodontic treatment need and dental caries experience were both associated with a reduction in quality of life, independent of each other. The study highlights the need for a thorough oral assessment, early orthodontic assessment, and preventive dental care to ensure better patient-centered results and overall oral health.