Investigating the dynamic relationship of sleep-disordered breathing, orthodontic treatment needs, and dental esthetics in the general population

Abstract

BACKGROUND:

Sleep-disordered breathing (SDB) is characterized by upper airway dysfunction and is linked to severe health issues. Individuals with SDB have distinct craniofacial morphology for which orthodontists are most suitable for the management due to their dental expertise.

AIM:

This study aims to discern key differences in dental parameters between individuals with and without SDB.

METHODS:

The present study is a cross-sectional observational study conducted for 12 months. Out of 70 participants, 35 were placed in the SDB group as per the Berlin questionnaire (BQ) and 35 in the control aged 18–22 years. Criteria excluded individuals with preexisting illnesses, missing teeth, tonsillectomy, orthodontic or jaw surgeries, cleft lip/palate, or craniofacial anomalies. Dental assessments included interdental width, palatal vault depth and shape, molar relation, overjet, and overbite. In addition, self-perceived orthodontic treatment needs were evaluated as a secondary measure.

RESULTS:

In the SDB group, interdental distances were significantly reduced in the canine, first premolars, second premolars, and molar regions by 2, 3, 4, and 1.8 mm, respectively. A noticeable V-shaped arch was observed. Overjet and overbite increased by 42.85% and 31.42%, respectively, with Class 1 malocclusion more prevalent than Class 2. The Berlin questionnaire identified 54.3% as high-risk SDB. The Index of Orthodontic Treatment Need-Esthetic Component (IOTN-AC) revealed that 68.6% of snoring participants required orthodontic treatment.

CONCLUSION:

Individuals with SDB exhibit a constricted maxilla and reduced interdental measurements, indicating a moderate risk. The Berlin questionnaire proves valuable in assessing SDB severity. Moreover, individuals displaying signs of SDB often present a high prevalence of orthodontic treatment needs, as indicated by the IOTN-AC.

Sleep-disordered breathing (SDB), characterized by upper airway dysfunction, is classified under the second category of the International Classification of Sleep Disorders (ICSD-3, 2015), encompassing conditions such as obstructive sleep apnea syndrome.[1] The rising attention to SDB stems from its potential impact on both systemic health and craniofacial structures, with orofacial anatomy playing a pivotal role in diagnosis. Mouth breathing, linked to increased nasal respiratory resistance, alters muscular balance, impacting craniofacial development and elevating the risk of malocclusion.[2,3] Recognizing the dynamic relationship between SDB, orthodontic treatment needs, and dental esthetics is essential for comprehensive health care. Orthodontists, possessing expertise in the evolution of dental components, are well-suited for managing SDB individuals.[4] Screening techniques, as routine clinical procedures, prove cost-effective in identifying undiagnosed patients.[5]

The BQ, a self-administered survey, aids in identifying snoring, falling asleep while driving, and sleep apnea.[6] In addition, individuals were provided with a self-perceived esthetic component (AC) questionnaire to gain insights into their dental perspectives. Numerous occlusal indices have been created to evaluate the extent of malocclusion and assist in establishing normative standards for orthodontic treatment. The Index of Orthodontic Treatment Need (IOTN) is particularly valuable for categorizing the severity or extent of occlusal features and has proven instrumental as an epidemiological tool for assessing treatment requirements among individuals. The IOTN integrates both a dental health component and an AC as outlined by Brook and Shaw.[7] Despite the potential impact of dental characteristics on SDB etiology, this aspect remains underexplored in the literature, necessitating attention. Therefore, the present research aimed to identify the intricate connections between SDB, as assessed by the Berlin questionnaire, orthodontic treatment needs, and dental esthetics within the general population. This comprehensive research initiative was undertaken to identify and shed light on valuable insights into both the fields of sleep medicine and orthodontics through a multidisciplinary approach by various specialists.

Methods

The present study design is a cross-sectional observational study. Ethical approval was obtained from the Institutional Ethics Committee Board with JSSIEC/58/2020 on January 1, 2021. Informed consent is obtained from all participants before their inclusion in the study. Following the acquisition of informed consent, participants underwent study cast analysis, completed a sleep behavior questionnaire (Berlin questionnaire), and responded to an AC questionnaire based on orthodontic treatment needs (IOTN-AC), as shown in Figure 1.

Figure 1.

Study cast analysis. SDB: Sleep-disordered breathing, IOTN-AC: Index of Orthodontic Treatment Need-Esthetic Component

Sample size

As per medical literature, establishing an optimal sample size for evaluating orthodontic treatment needs in individuals with SDB, aiming for a relative precision of 15% and a 95% confidence interval, necessitates a minimum of 32 subjects identified as positive for SDB. The study involved 70 individuals, with the case group comprising 35 individuals identified with positive indicators of sleep apnea from the department of otolaryngology, and the control group consisting of 35 healthy individuals recruited from the orthodontics department’s outpatient department from the period of April 2021 to March 2022. The control group comprised 18 males and 17 females, while the case group included 16 males and 19 females, with an age range of 18–22 years. The inclusion criteria for the selection of individuals with SDB included the absence of any preexisting illnesses or congenital defects. Individuals with partially or completely missing teeth in an arch, a history of tonsillectomy, orthodontic treatment, or jaw surgeries, as well as those with cleft lip and/or palate or any other craniofacial anomalies are considered exclusion criteria.

Study model analysis

Alginate impressions were taken of both the upper and lower teeth from all participants. Subsequently, dental casts were prepared by pouring dental stones into these impressions. A digital caliper was employed for measuring various parameters, including intercanine distance, interpremolar distance, and intermolar distance. In addition, observations were made for overjet, overbite, palatal depth, malocclusion type, and the shape of the maxillary arch. The recording of malocclusion types adhered to Angle’s classification [Figure 2].

Figure 2.

Classification of participants’ malocclusion

The presence of certain characteristics indicated a maxillary constriction, including a palate that is narrow, deep, and elevated. The posterior teeth may or may not exhibit a crossbite or an edge-to-edge relationship with the lower teeth.

Berlin questionnaire (BQ)

Individuals who reported to the hospital with difficulty breathing were asked to fill in the questionnaire as a basic screening process. Based on their answers, the individuals were grouped into high and low risk. At least two clinical signs from each category had to be present for a patient to be classified as high risk, which was scored 1. A lower-risk group was assigned to those who denied ongoing symptoms or who only had one symptom per category, which was scored 0.[8]

Index of Orthodontic Treatment Need-Esthetic Component

The evaluation of dental esthetics utilized the IOTN-AC as proposed by Brook and Shaw. Participants were presented with 10 photographs of anterior teeth depicting varying degrees of malocclusion. They were asked to identify the photograph that closely resembled their dentition [Figure 3]. Based on the selected images, the scores were categorized as follows: 0 – no need for treatment (images 1–4), 1 – moderate/borderline need for treatment (images 5–7), and 2 – need for treatment (images 8–10).[7]

Figure 3.

Participants showing the esthetic component of the Index of Orthodontic Treatment Need (Brook and Shaw)

Statistical analysis

The statistical package was analyzed using MS Excel, followed by analysis using SPSS Version. 23 (license to the institute, SPSS: IBM Corporation, Armonk, New York). Mann–Whitney U test was used to compare the parameters between the groups. Data were expressed as median and interquartile range. P < 0.05 was considered statistically significant.

Results

Study model analysis

The dental measurements for the case group were as follows: the intercanine distance was 31.54 ± 4.4 mm, the first premolar was 33.29 ± 3.2 mm, the second premolar was 36.4 ± 4.3 mm, and the molar region was 43.4 ± 4 mm. These values proved to be statistically significant [Table 1]. Out of 70 participants, 20 (57.1%) participants had Class 1 malocclusions and 15 (42.9%) had Class 2 malocclusions among SDB participants whereas 22 (62.9%) had Class 1 malocclusion and had Class 2 malocclusion among the control group. No participants in the case or control groups had Class 3 type of malocclusion. The V-shaped arch palate in the maxilla was proved to be more prevalent, i.e., 24 (68.6%) in SDB individuals, but the U-shaped arch palate was more appreciated, i.e., 22 (62.9%) in the control group. There was an increase of 15.35% and 31.58% recorded in the overjet and overbite, respectively, in the SDB group. The crowding of teeth was seen in 23 (65.6%) out of the 35 participants of SDB [Table 2].

Table 1.

Showing the intercanine, interpremolar and intermolar relationship in case and control

	Group
	SDB (mm), mean±SD	Control (mean±SD)
Intercanine	31.54±4.4	35.19±3.5
Interpremolar 1	33.29±3.2	38.5±0.32
Interpremolar 2	36.4±4.3	43.50±1.00
Intermolar	43.4±4	46.36±4.2

SD=Standard deviation, SDB=Sleep-disordered breathing

Table 2.

The Class 1 and Class 2 malocclusion in case and control

	Group
	SDB, n (%)	Control, n (%)
Malocclusion
Class 1	20 (57.1)	22 (62.9)
Class 2	15 (42.9)	13 (37.1)
Shape of the maxillary palate
V palate	24 (68.6)	13 (37.1)
U palate	11 (31.4)	22 (62.9)
Overjet
Present	15 (42.85)	9 (31.42)
Absent	20 (57.14)	26 (74.2)
Overbite
Present	11 (31.42)	8 (22.8)
Absent	24 (68.5)	27 (77.1)
Crowding
Absent	12 (34.3)	10 (28.6)
Present	23 (65.6)	25 (71.4)

SDB=Sleep-disordered breathing

Berlin questionnaire (BQ)

The Berlin questionnaire categorizes individuals into three groups and assigns scores to two domains: high risk and low risk. According to the questionnaire, 68.4% of participants fell into the high-risk category, while 31.3% were classified as low risk. The prevalence of SDB was found to be higher in males compared to females, as indicated in Table 3.

Table 3.

The low and high risk of the Berlin questionnaire in case and control

Group	Risk
	Low risk		High risk
	Male, n (%)	Female, n (%)	Male, n (%)	Female, n (%)
1: SDB	5 (14.2)	6 (17.1)	19 (54.2)	5 (14.2)
2: Control	10 (28.5)	16 (45.7)	9 (25.7)	0
Total	15	22	28	5

SDB=Sleep-disordered breathing

We conducted a statistical analysis to assess the intensity of snoring and the frequency of snoring episodes among participants. Our findings revealed that 19 participants (54.3%) snored as loudly as talking, representing the highest proportion. This was followed by 15 participants (42.9%) who snored slightly louder than talking and 1 participant (2.9%) who snored louder than talking [Table 4].

Table 4.

The loudness of the snores

	How loud individual snores
	0, n (%)	1, n (%)	2, n (%)	3, n (%)
1: SDB	0	15 (42.9)	19 (54.3)	1 (2.9)
2: Control	35 (100)	0	0	0
Total	35 (50.0)	15 (21.4)	19 (27.1)	1 (1.4)

0=No score, 1=Slightly louder than talking, 2=As loud as talking, 3=Louder than talking, SDB=Sleep-disordered breathing

The occurrence of participant snoring episodes was observed in 14 individuals (40.0%), indicating approximately 3–4 times/week [Table 5].

Table 5.

The frequency of the participant snoring

	Frequency of the participant snoring
	0, n (%)	1, n (%)	2, n (%)	3, n (%)	4, n (%)
1: SDB	0	4 (11.4)	14 (40.0)	11 (31.4)	6 (17.1)
2: Control	35 (100.0)	0	0	0	0
Total	35 (50.0)	4 (5.7)	14 (20.0)	11 (15.7)	6 (8.6)

0=No snoring pattern observed, 1=Almost every day, 2=3–4 times per week, 3=1–2 times per week, 4=Rarely or never, SDB=Sleep-disordered breathing

Index of Orthodontic Treatment Need-Esthetic Component

When comparing cases and controls using IOTN-AC, it was found that 24 individuals (68.6%) in the SDB case group believed they needed orthodontic treatment, while 20 individuals (57.1%) in the control group shared this perception [Table 6].

Table 6.

The treatment requirement based on the Index of Orthodontic Treatment Need-Esthetic Component in case and control

Group	IOTN-AC
	0, n (%)	1, n (%)
1: SDB	11 (31.4)	24 (68.6)
2: Control	15 (42.9)	20 (57.1)
Total	26 (37.1)	44 (62.82)

0=No need for treatment and 1=Need for treatment, IOTN-AC=Index of Orthodontic Treatment Need-Esthetic Component, SDB=Sleep-disordered breathing

On comparing the various parameters of the study model, BR questionnaire, and IOTN-AC between the SDB group and the control group, statistically significant differences were observed where the significance level was set at P < 0.05. These variances encompass various aspects such as dental measurements, arch shape, overjet, overbite, snoring intensity, frequency of snoring episodes, fatigue prevalence, BQ risk, and IOTN-AC [Table 7].

Table 7.

Comparison of parameters of study model, Berlin questionnaire, and Index of Orthodontic Treatment Need-Esthetic Component among case and control

	Group				P
	Cases		Control
	Median	IQR	Median	IQR
Molar	44.00	40.00–47.00	47.00	44.00–48.00	0.002*
Second premolar	37.00	34.00–40.00	39.00	37.00–42.00	0.006*
First premolar	33.00	31.00–35.00	35.00	33.00–40.00	0.007*
Canine	32.00	30.00–34.00	34.00	33.00–36.00	0.008*
Depth	24.00	22.00–25.00	22.00	20.00–23.00	0.001*
Overjet	7.00	4.00–9.00	5.00	3.00–8.00	0.275
Overbite	5.00	3.00–6.00	4.00	2.00–6.00	0.021*
Shape	1.00	1.00–2.00	2.00	1.00–2.00	0.009*
Malocclusion	1.00	1.00–2.00	1.00	1.00–2.00	0.628
Crowding	1.00	0.00–1.00	1.00	0.00–1.00	0.609
Constricted maxilla	1.00	1.00–1.00	1.00	0.00–1.00	0.075
Snore	1.00	1.00–1.00	0.00	0.00–0.00	<0.001*
Loud	2.00	1.00–2.00	0.00	0.00–0.00	<0.001*
Often	2.00	2.00–3.00	0.00	0.00–0.00	<0.001*
Fatigue	2.00	2.00–3.00	0.00	0.00–0.00	<0.001*
BP	0.00	0.00–0.00	0.00	0.00–0.00	1.000
Berlin’ risk	1.00	0.00–1.00	0.00	0.00–0.00	<0.001*
IOTN-AC	1.00	0.00–1.00	1.00	0.00–1.00	0.198

*P < 0.05. IOTN-AC=Index of Orthodontic Treatment Need-Esthetic Component, IQR=Interquartile range, BP=Blood pressure

Discussion

In recent times, the acknowledged health repercussions of undiagnosed SDB highlight the need for orthodontic intervention. Orthodontists, equipped with expertise in orofacial development and orthodontic correction, are well-positioned to treat SDB patients. However, comprehensive knowledge of the interplay between SDB and orthodontic treatment, including the awareness of malocclusion, is essential.[9,10] This study aims to evaluate dental characteristics and orthodontic treatment needs in individuals with SDB, revealing that a simple questionnaire (BQ),[8] dental analysis, and IOTN-AC can effectively screen and assess these patients.[7]

Examining dental models aids in the investigation of malocclusion forms. According to Johal et al. and Seto et al., study model diagnosis plays a crucial role in identifying SDB.[11,12] Hence, our analysis of the study models revealed a significant difference observed in SDB patients. To achieve a deeper understanding, we committed to examining maxillary morphology diligently.

The present study revealed a notable 2-mm disparity in the intercanine distance between the case and control groups. Nainan et al. suggested that the constriction in the anterior region of the maxillary arch could be attributed to individuals’ habit of breathing through the mouth.[13] In addition, our study demonstrated a 3-mm variance in the first interpremolar distance, a 4-mm difference in the second interpremolar distance, and a 1.8-mm reduction in the molar region between the case and control individuals. These findings align with the results of studies conducted by Seto et al. and Nainan et al. indicating a noticeable maxillary constriction in the molar, premolar, and canine regions compared to the control group.[12,13]

The present study showed that crowding was observed in 65.7% of individuals within the case group, exhibiting a positive correlation with SDB. A similar pattern is evident in a study conducted by Huynh et al.[14] Our study revealed an augmentation in the V-shaped palatal vault among individuals with SDB. These findings align with the results of studies conducted by Banabilh.[9]

Our study indicates a 15.35% increase in overjet and a 31.58% increase in overbite among SDB patients. This observation finds support in the research of Miyao et al.,[15] Cazzolla et al.,[16] and Galeotti et al.,[17] all of which suggest a close relationship between overjet, overbite, and symptoms of sleep apnea.

The present study recruited 35 SDB participants of which 20 exhibited a Class 1 molar relation, while 15 showed a Class II molar relation. These findings are consistent with the findings of Patil and Joshi,[18] who highlighted the prevalence of Angle’s Class I malocclusion over Class II malocclusion. While it is commonly believed that Class II malocclusion is more prevalent due to a retruded mandible, a clinical sign observed in individuals with SDB, recent studies caution against this assumption. Research by Galeotti et al.[17] and Al-Madani et al.[19] supports the notion that Class 1 malocclusion can also significantly contribute to SDB, aligning with our study’s findings. This observation, rarely noted in existing literature, is a unique aspect of our study.

Several sleep questionnaires have been developed to aid clinicians in identifying individuals from the general population who may be prone to developing SDB. In a study conducted by Sharma SK et al., which examined various questionnaire types, the Berlin questionnaire (BQ) demonstrated the highest sensitivity in identifying mild-to-moderate sleep apnea. As per the BQ criteria, individuals scoring two or more positive responses in two categories are categorized as “high risk,” whereas those with fewer than two positive scores are considered “low risk.”[8] In our study, 45.7% fell into the low-risk category, while 54.3% were classified as high risk. The results were inconsistent with Saleh et al. who showed reliability and validity of the Berlin questionnaire BQ in the detection of SDB at-risk patients.[20] The present study also showed statistical significance in the intensity of snoring, the frequency of snoring episodes, and the prevalence of fatigue among SDB patients. This result is in accordance with Saleh et al., Alotaibi et al., and Al-Dekhel and Banabilh.[20,21,22]

The present study revealed indications of orthodontic treatment necessity in both the groups. Among participants with SDB, 68.6% were found to require orthodontic treatment, unbeknownst to them. These results were supported by Al-Dekhel and Banabilh et al. who demonstrated the correlation between esthetic needs and individuals with SDB in their study.[22]

Limitation of the study

The study’s limitations encompass a cross-sectional design limit of hospital-based screening potentially small and nonrepresentative sample size with selection bias, hindering broad generalizability. Self-reporting bias in tools such as the Berlin questionnaire introduces inaccuracies. The study lacks an exploration of interdisciplinary challenges and external factors influencing SDB and orthodontic concerns. Acknowledging these limitations, including sample size constraints, biases, and tool-specific drawbacks, ensures a nuanced interpretation of findings and highlights areas for further research or consideration in practical applications at the community level.

The current study has shown that individuals with SDB can be identified by orthodontists at chairside evaluation and screening procedure using a simple questionnaire such as BQ, dental analysis, and IOTN-AC was used to prove additional confirmation and to better understand the perception regarding orthodontic treatment needs.

Conclusion

This study reveals that individuals with SDB commonly demonstrate a constricted maxilla, along with characteristics such as overjet, overbite, palatal vault shape and depth, and reduced inter-dental measurements, suggesting a moderate risk. Furthermore, those exhibiting signs of SDB often manifest a higher prevalence of orthodontic treatment needs, as indicated by the IOTN-AC.

The Berlin questionnaire and IOTN-AC emerge as effective, rapid, and cost-efficient diagnostic tools that should be routinely integrated into chairside diagnoses. Consequently, individuals with SDB can undergo timely diagnosis and comprehensive treatment through a collaborative effort involving a multidisciplinary team, which may include an orthodontist, an ear, nose, and throat specialist, and various medical or dental experts.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.