The influence of maxillary expansion on nasal septum development: a narrative review

Introduction

Nasal septum deviation (NSD) refers to the deviation of the nasal septum from the midline that causes nasal dysfunction. The nasal septum deviates in a variety of locations and shapes, with various types (1). It can be congenital or acquired, and the incidence is about 63–65% (2,3). When there is a serious NSD, it will impact the structure and function of the nose and jaw (4). It will block air circulation, causing nasal respiratory disturbance (5). Meanwhile, it will lead to the growth of the patient’s nasal concha and mucosal adhesion, resulting in hypertrophy of the nasal concha (6), increased nasal respiratory resistance, and an imbalance of airflow resistance on both sides of the nasal cavity (7,8). The mouth will compensate for the poor nasal breathing, resulting in mouth breathing habits, nasal dysplasia (9), and maxillofacial malformations in teenagers with NSD (10). There are two key growth peaks of nasal septum in the first two years after birth and adolescence (11), because nasal septal cartilage and nose continue to grow until the age of 16–17 (12). Surgery is the traditional treatment for NSD that causes a severe grade of obstruction (≥16°) (13). However, adult and adolescent patients with NSD who underwent surgery may suffer from deviation again, with a higher incidence in adolescents. The unmatched growth rate between nasal septal cartilage and the midfacial skeleton easily leads to re-deviation, limiting the application of the surgery in adolescents (14). Therefore, nasal septum surgery is normally recommended to be postponed to adulthood, before which only conservative treatment is performed, and no effective intervention is available.

Maxillary transverse deficiency (MTD) is a common craniofacial skeletal malformation. It is often manifested as the disharmony between the width of upper dental arch and jaw, posterior region unilateral or bilateral crossbite, and often accompanied by anterior teeth crowding, wide buccal corridor gap when smiling, and high vault (15,16). Characterized by posterior crossbite, its multiple symptoms often occur simultaneously, also known as maxillary deficiency syndrome (17). Patients with MTD can have a high-arched hard palate, crowded dentition, and narrow arch (18). As the adjacent structure of nasal septum, if maxilla is abnormal, it will also affect the normal development of nasal septum, resulting in NSD (19,20). On the one hand, the high-arched hard palate invades the nasal cavity’s development space, limiting the growth of nasal septum, and eventually leading to NSD. The nasal airflow resistance increases as the distance between the nasal septum and the lateral wall of the nasal cavity reduces, limiting nasal respiration (21). On the other hand, mouth breathing caused by nasal obstruction leads to abnormal lip and tongue position, downward and backward rotation of mandible, and turbinate enlargement, all of which contribute to the reduction of nasal airway volume (22).

In view of the significance of the interplay between MTD and NSD, the effect of orthodontic methods such as rapid maxillary expansion (RME) on NSD has begun to attract people’s attention in recent years. However, there is no clear conclusion about the effect of expansion on NSD. Therefore, this paper reviews the relevant literature. We present this article in accordance with the Narrative Review reporting checklist (available at https://fomm.amegroups.com/article/view/10.21037/fomm-24-2/rc).

Methods

In this narrative review, the relevant English literature was searched via Google Scholar, PubMed and Embase databases using the following keywords: nasal septum deviation and rapid maxillary expansion. The following terms were explored to aid in the literature search as well: surgically assisted rapid maxillary expansion (SARME), slow maxillary expansion (SME) and micro-implant assisted rapid maxillary expansion (MARME). To allow for a thorough review, there was no limitation on the year of publication. The published articles with full text from 1975 to 2022 were included (Table 1).

Discussion

Maxillary expansion techniques

Overview of maxillary expansion

Maxillary expansion is commonly used in orthodontic treatment for MTD. RME, SME, SARME and MARME are the four most common methods of maxillary expansion.

Mechanisms of maxillary expansion

RME is an effective method to increase the maxillary transverse width (23). The patient employs an expansion screw, opening the expander spiral twice a day, a quarter circle each time, with the arch expansion amount of 0.5 mm/day. The duration of arch expansion is 2–3 weeks. By using the growth potential of adolescence, it can stably and effectively open the palatal suture, correct the maxillary and dental arch stenosis, and thus reduce the high arch of the hard palate (24,25). Therefore, RME should be performed before the end of growth (before the age of 18 for males and 16 for females) (26). During RME treatment, the continuous and powerful expansion force is quickly transmitted to the maxilla, expanding the transverse width of the dental arch and the maxilla, and improving the smile aesthetics (25). Simultaneously, the impact of RME is not only limited to the maxilla and dental arch, but also extends to the surrounding parts of the maxilla.

SME and RME share strong connections and similarities. The main difference between SME and RME is the frequency of expansion (the rotation of the daily screw). SME is to open the spiral once every two days, one quarter turn each time, with a pantograph expansion efficiency of 0.25 mm/day. When the patient lacks growth potential and does not meet the conditions for RME, SME is performed with intermittent and small force to slowly expand the arch, which can still provide good treatment effects for older patients with poor growth potential, but it takes longer than RME (27). Bucci (28) discovered that SME, as RME, has the same effect in increasing maxillary width by reviewing. According to Lo Giudice (29), although SME produces less numerical change than RME (due to the small sample size, significance cannot be tested at the level of 0.05), SME also has the effect of increasing nasal bone width (increased on average 2.67 mm for SME and 3.13 mm for RME) and total nasal cavity volume (increased on average 1.68 cm³ for RME and 1.25 cm³ for SME). It is also worth noting that SME has a lower incidence of root resorption (30). Therefore, given the lack of palatal suture growth potential and other comprehensive factors in late adolescent patients with bone maturity, SME is more conducive to achieving a stable and safe therapeutic effect and seems to be a painless alternative to RME (25).

When a patient’s bone is mature, the bone suture calcification has a strong resistance to bone movement and reconstruction expected by simple correction (31). Therefore, a modified Le Fort I maxillary osteotomy is performed, not including the separation of the pterygomaxillary suture when the maxilla is severely transversely underdeveloped (greater than 5 mm). In conjunction, a sagittal palatal osteotomy is carried out, running from the midline of the alveolar bone, between the central incisors, to the posterior nasal spine (32). After the osteotomies, the expander is activated to reduce the expansion resistance of the palatal suture and achieve the purpose of broadening the width of the maxilla (33). For bone-mature patients who do not respond to RME treatment, SARME has a significant maxillary (31,34), nasal bone and soft tissue (35) expansion effect, as well as the function of expanding the volume of upper airways (36). However, due to the auxiliary intervention of surgery, there will inevitably be corresponding surgical risks.

MARME is a new technology with less invasive injuries and is more appropriate for young adults (37,38). It uses four additional micro-implants as the anchorage with the assistance of palatal bone tissue, reducing the excessive load of the conventional rapid expansion device on the anchorage teeth, having a greater bone effect, and providing a more safe and stable effect (39). Furthermore, the strengthening effect of micro-implants on RME makes it easier to keep the anchorage teeth in place. Thus, it can reduce the pressure on alveolar bone, thereby reducing the related periodontal side effects (40).

Indications and contraindications for maxillary expansion

The choice of expansion method and the effect of expansion are limited by the patient’s bone density (41). After expansion treatment, the mid-palatal suture was separated and reintegrated to achieve the expansion effect. However, the palatal suture stopped fusing at about the age of 19 (42). Angelieri developed a classification according to the overall mid-palatal suture morphology using CBCT. The maturity of the mid-palatal suture is divided into five categories from A to E. It can help evaluate the growth potential of patients to avoid the failure of RME in adolescents and adults or the unnecessary application of SARME (43) (Table 2).

Effects of maxillary expansion on nasal septum development

Impact of maxillary expansion on nasal septum morphology

At present, NSD with clinical symptoms is treated surgically. However, due to the unmatched growth rate of nasal septum cartilage and midfacial bone, adolescent patients can only receive conservative treatment, such as medicine. In terms of the original expansion effect of using expansion to correct MTD, scholars observed changes in nasal cavity structure, including nasal septum (44). As early as 1975, Gray (45) extended the indications of RME to include diseases other than dental indications, such as nasal airway dysfunction, nasal septum malformations, recurrent ear or nasal infections, a combination of allergic rhinitis and asthma, and before septoplasty. Since then, many scholars have studied and reported on the effects of various maxillary expansion methods on the nasal septum and other nasal structures and functions.

Impact of RME on nasal septum morphology

Scholars have conducted numerous studies and discussions on the impact of RME on the nasal septum based on the cross-formation mechanism of NSD and MTD, as well as the influence of maxillary expansion on the entire facial middle.

Some scholars have observed that RME facilitates the growth of the nasal septum and increases its length. Maspero (46) performed RME for 39 growing patients with NSD more than 1 mm from 6.2 to 12.3 years (mean 8.6±1.5 years) until the expected expansion was obtained. The expander was left in place for passive expansion. CBCT projection measurements before RME and after expander removal (12 months interval) revealed that, after RME, the length of nasal septum increased, statistically significant in the lower tract, and the deviation of nasal septum also decreased both in its middle and lower tracts. In the study of Farronato (22), 140 patients aged 7.62±0.7 years with MTD and NSD greater than 1 mm were included. One hundred of them were treated with Hyrax arch expander for RME, while the remaining 40 were given medication for neurovascular headache without intervention. Cephalometric measurements were taken before treatment (T0), at the removal of the appliance (T1) and after 6 months of maintenance (T2). It was found that the length of nasal septum increased 1.36 mm in its upper tract and 2.34 mm in the lower tract. This trend is similar to that reported in Maspero’s study (46), which showed that the nasal septum increased 0.47 mm in its upper tract and 0.53 mm in the lower tract, but more significant. It was also observed that RME can increase nasal cavity volume, reduce air resistance, and improve breathing pattern by making the nasal-maxillary complex move downward and forward, which has a favorable effect in promoting the growth of maxillary complex (22).

Meanwhile, certain studies have demonstrated that RME can also correct the deviation of the nasal septum. In the study of Ronsivalle (47), cone-beam computed tomography (CBCT) scan of 40 children with TMD in pre-pubertal stage according to the CVMS method (from stage CS1 to stage CS3), who received tooth-borne (TB) RME or bone-borne (BB) RME, were included. The analysis was performed by dividing the actual length of the septum by the desired length in the mid-sagittal plane to measure NSD based on the tortuosity ratio (TR). It was observed, through CBCT scans, it was observed that subjects exhibited a statistically significant reduction of the TR value from before appliance installation (T0) to after a 6-month retention period (T1) whether TB or BB was used. Gokce (48) applied Hyrax expander to 15 patients with a mean age of 12±1.6 years with NSD until 20% overcorrection of posterior crossbite was achieved, and then the expander was locked and maintained for 3 months after expansion. CBCT was used to reconstruct patients’ anatomical structure at three time points: before RME treatment (T0), after screw fixation (T1), and after orthodontic removal (T2) (interval 12 months). Used TR to quantify the deflection rate and observe the scanning results of three-time nodes, it was found that the deviation decreased significantly between T0–T1 and T0–T2, but the difference between T1–T2 was not found to be significant. Bruno (49) accidentally found NSD in 20 pre-pubertal patients with an average age of 10±2 years during RME treatment. By comparing the cross-sectional and coronal data of two CBCT records before and at least 12 months after treatment, it was found that the NSD curvature index, which is the ratio of length of the curve to the length of an imaginary line in the midsagittal plane, and area changed, calculated as the integral from the curve to an imaginary line in the midsagittal plane, suggesting the potential positive effect of RME on early adolescent patients with NSD.

However, some studies also have obtained different results. Veloso (50) treated 40 patients with an average age of 11.1±2.2 years with RME using a Hyrax expander. The patients were followed up monthly during the 3-month retention period. It was found that there was no notable change in NSD before and after RME treatment. This may be because the patients’ NSD is caused by cleft lip/palate, and the two are related in development (51,52). The maxillary effect of RME in patients with cleft lip/palate is only limited to the alveolar area. Aziz (53) grouped patients as Bone Anchored Maxillary Expansion sample with 14 patients averaging 14.2±1.3 years, Tooth Anchored Maxillary Expansion sample with 12 patients averaging 14.1±1.4 years and control sample with 7 patients averaging 12.9±1.2 years. CBCT scans before and after appliance removal showed no significant changes in NSD, as calculated by the ratio of length of the curve to the length of an imaginary line in the mid sagittal plane, regardless of whether RME was applied or not and the degree of NSD. However, this study may suffer from obvious limitations and be strongly influenced by small sample size, higher average age, and short follow-up periods. In the study of Kamińska (54), there is also the limitation of the sample having higher age. It included 30 patients with severe MTD aged from 10 years, 6 months to 30 years, 1 month, no vertical improvement of NSD was observed before and after RME treatment. In Chen’s study (44), a total of 15 adolescents with a median age of 9.57±1.51 years, who had MTD accompanied by NSD, were treated with RME. No significant change in the deviation of the nasal septum was found, but there was no follow-up conducted in this study.

Impact of other maxillary expansion method on nasal septum morphology

SARME is mostly used for adult patients without growth potential, so the nasal septum is mostly unchanged after treatment. Dias (55) detected adults before, immediately after, and 6 months after SARME, and found no significant difference in the lower third, front, back, height, and symmetry of the nasal septum. Barrabé (56) found that only one of the 23 patients had NSD after SARME during a longer follow-up (at least 1 year). Seeberger (57) did not find that SARME caused obvious deviation of nasal septum by comparing the first month before SARME with the sixth month after SARME. Landim (58) also found that there was no significant change in the position of nasal septum and turbinate after SARME at the same observation time. Altug-Atac (59) compared the changes of the nasal septum before and after RME or SARME, and there was no change in the position of the nasal septum.

There is no research on the effect of SME or MARME on NSD.

Comparison of different literature results on NSD

The therapeutic mechanism and basic principle of RME can be used to clarify the theoretical basis of NSD and maxillary formation. The effect of RME on nasal septum varies with age, with better long-term outcomes observed in younger patients (45). We can find that in the studies (22,46-49) where RME improves NSD significantly, the patients receiving treatment are relatively young and has growth potential; however, in the studies (50,53,54) where the improvement of NSD was not significant, the patients were older. The growth of the nasal septum gradually stops at 16–18 years old. When the patient is in early adolescence, RME utilizes the patient’s growth potential, improves the breathing mode, removes obstacles, and creates a favorable growth environment and sufficient space for nasal septum growth by opening the maxilla and nasal bones thus correcting the degree of NSD (22,46). When the patient is older, even if RME provides conditions for growth, the improvement effect is extremely limited because the growth has been completed. Thus, for adult patients with mature bone, the nasal septum will not change significantly after expansion treatment (Table 3).

Changes in factors related to the development of the nasal septum following maxillary expansion

Although different studies differ in the significance of the results, the positive effect of RME on nose and nasal septum is undeniable (44,46). NSD and midfacial hypoplasia are both thought to cause upper airway obstruction (7,19). Therefore, based on correcting the original structural abnormalities, maxillary expansion also has a significant improvement effect on respiratory-related functions (46). Therefore, when discussing the curative effect of expansion treatment, its improvement effect on respiratory related structure and function should also be paid attention to.

Changes in nasal structure and airway volume following maxillary expansion

A meta-analysis by Buck (61) reported that, after RME, the lateral wall of the nasal cavity shifts during bone expansion, which is associated with the direct site of the expander (62). Studies (63,64) have shown that the average increase in the width of the nasal base is often greater than the average increase in the width between the nasal walls, supporting the craniofacial complex to form an inverted ‘V’ shaped opening on the coronal plane. Garib (65) found that RME increases the area of the nasal cavity at the transverse nasal floor level by one-third of the device expansion. However, one study (29) has obtained different results from “V” expansion. They believe that RME expands the nasal cavity by promoting maxillary separation in a “pyramid” shape, with the largest expansion located at the level of the incisor (below the nasal flap) and the rotation center of the frontonasal suture (29). The increase of the width between the nasal floor and the nasal wall of the above two types of openings is the same and has an obvious correlation with the change of the palatine suture.

Through nasal bone changes, RME can also increase the total volume of the upper airway and balance the volume of the left and right nasal cavities (reduce the volume difference between the left and right nasal cavities) and has a stable long-term effect (61,66). The total upper airway volume was defined as the sum of the nasal cavity, nasopharynx (NP), palatopharynx (PP), glossopharynx (GP), and the hypopharynx (HP), namely from the top of the pharynx to the plane passing from the epiglottis base. PP and GP together comprise the oropharynx (OP) (67). Accurate quantification of airway changes is particularly important to accurately determine the effect of RME on the upper airway. The commonly used three-dimensional (3D) imaging, computed tomography (CT) and CBCT, have verified to be tools for accurate estimation of airway volume (68,69). Studies have firmed that nasal airway increased after RME (59,61). For NP, Görgülü found that the increase in the nasopharyngeal airway was significant, by about 12.1%. Almuzian (70) reported that the expansion of the NP airway is mushroom-like (upper expansion, significant reduction in the middle, and slight reduction in the lower), including 15.2% expansion in men and 12% expansion in women, which is like the conclusion of Görgülü (71). Lanteri (72) conducted a control study of RME and SME in patients with mixed dentition and found that SME could increase the pharyngeal airway of patients with MTD, and there was no statistically significant difference with RME. But the long-term stability of SME in nasal changes remains to be further discussed (28). In DiCosimo (66), the increase in NP volume was significant. It also observed that the increase in oropharyngeal volume was comparable. In the study of Chen (44), nasal cavity, NP, OP, pharyngeal cavity volume also increased, but no statistical difference. However, in the study of Zeng (63), there was no significant change in the throat airway. The reason for these differences may be due to differences in patients’ age and growth potential. The increase of nasal cavity volume can effectively reduce air resistance and improve the life quality of patients with oral breathing (70,73). As for the different change effects of each part of the upper airways, it is due to the adaptation of the soft tissue, which leads to a decrease farther down the airway (74). In addition, according to the research of Pangrazio-Kulbersh (62), there is no significant change in the rear airway volume after RME treatment.

No studies have been conducted on the changes in airways following SME, except for pharyngeal airways (72).

For bone-mature adults who have lost their growth potential, after SARME treatment, the nasal structure and airway volume will also change like RME. Kayalar (35) found that nasal hard tissue (pyriform aperture) and nasal soft tissue [alar base width (ABW) and alar width (AW)] significantly widened after SARME treatment in patients with mature bone, with a significant positive correlation between the two. For airway volume, through control study, Altug-Atac (59) found that SARME, like RME, could increase the size of the nasal cavity and reduce the airway resistance in the nasal cavity. Except for the significant increase of nasal width in RME group, the increase of nasal parameters in SARME group and RME group was similar, which was statistically significant. This result is the same as that of Bicakci (75). Magnusson (76) observed that the minimal cross-sectional area of the nasal cavity increased after SARME. However, 18 months after surgery, the treatment indicators of SARME were not significant, suggesting that the long-term treatment effect of SARME may not be stable.

Chun (40) found that MARME significantly increased the nasal width relative to the first molar area. Maxillary was triangular expansion in general (the increase of the width of anchor teeth, maxillary width and nasal width decreased in turn). At the same time, it has a significant effect compared with the RME group and has fewer recurrences during the three-month consolidation period. In addition, studies have confirmed that MARME can effectively expand the volume of the nasal airway and increase the volume of NP, suggesting that it has a positive effect on reducing nasal resistance and improving nasal ventilation (77).

Changes in nasal airflow patterns and nasal function following maxillary expansion

Current evidence suggests that RME reduces nasal resistance and increases nasal flow (78). In terms of nasal airflow, Chen (44) analyzed the children with MTD and NSD treated by RME through computational fluid dynamics (CFD) to simulate the dynamics of airflow and found that RME can make the airflow in both nasal cavities become relatively symmetrical and reduce the maximum airflow velocity. The reduction of the maximum airflow velocity in a certain extent is beneficial to the nasal cavity because it will prolong the residence time of the gas in the nasal cavity, which is conducive to the realization of the airflow heating function of the nasal cavity (79). The results of Chen also showed that the nasal resistance was reduced, and it changed from the original sharp change to stable hypotension, which was conducive to the development of nose. Iwasaki (80) found that after RME the nasal pressure and nasal ventilation flow rate of patients in the growth period decreased, and the nasal congestion symptoms were improved. In addition, due to the improvement of respiratory function, olfactory function will be improved after RME (81). In the study of Gray (45), about 80 % of patients had changes from mouth breathing to nasal breathing after treatment. As for the reasons for improved nasal ventilation, Almuzian (70) suggested that it is due to the reduction of nasal resistance secondary to immediate expansion of NP. However, McNamara (74) suggested that the reduction of nasal resistance was secondary to the change of respiratory mode. It is worth noting that the improvement of nasal respiratory function is closely related to the severity of nasal stenosis before treatment, that is, the narrower the nasal cavity is, the more obvious the improvement of nasal respiration after expansion (44).

There is no report on respiratory changes after SME.

By using Acoustic rhinometry (Rhino Scan) to measure the structural valve (from the nostril rim to the anterior border of the inferior turbinate) and the functional valve (from the anterior border of the inferior turbinate to the isthmus nasi), Magnusson (76) reported that two minimum cross-sectional areas of nasal cavity increased, and the nasal airflow resistance decreased in patients after SARME. The study showed that the subjective nasal congestion symptoms of the patients who had nasal congestion symptoms before the operation were significantly improved after the start of treatment, and the increase in the minimum cross-sectional area of the nose was significantly related to the improvement of nasal congestion.

Studies have confirmed that MARME can effectively expand the area and volume of the nasal airway and increase the volume of the NP, suggesting that it has a positive effect on reducing nasal resistance and improving nasal airway ventilation (77,82) (Table 4).

Implications for clinical practice and research

Clinical considerations on aesthetics

With the deepening of research, the effect of expansion therapy has experienced a “development trilogy” of structure, function, and aesthetics. Recently, with the improvement of people’s awareness and attention to beauty, the effect of maxillary expansion therapy on facial soft tissues has also been concerned and studied.

In terms of the appearance change of the middle face and its long-term stability of RME, Venezia (87) reported that nasal AW and nasal ABW increased after RME, but almost changed to the level before treatment one year later. The nasal length (NL), nasal filter length (NFL) and nasolabial angle (NLA) also increased slightly and then returned to the original level. Truong (88) also obtained research results that although the nasal soft tissue immediately increased after RME, it returned to normal development over time. This long-term change after treatment is worthy of attention because it has a potential link with efficacy and is closely related to facial aesthetics. Aras (89) found that the changes of facial soft tissue contour angle and H angle of RME patients were only related to the reduction of SNB and the more prominent soft tissue contour. Moreover, Badreddine (90) found that RME changed the shape and function of the nose and promoted the structural changes of bones and soft tissues.

Kayalar (35) found a significant positive correlation between changes in nasal hard tissue and soft tissue, suggesting that the changes in soft tissue after SARME treatment affect facial aesthetics. At the same time, due to various facial structures, different aesthetic effects will be observed due to other facial factors. However, in Nada’s research (86), the increase of nasal AW is only 1.2 and 1.4 mm and is like other research results (91,92). The authors believe that it is difficult to judge the impact of SARME on facial aesthetics from an aesthetic perspective. In another report (93), Nada concluded that the change of facial soft tissue at the outlet corresponds to the expansion effect obtained by SARME, which is consistent with the research conclusion of Kayalar (35). The authors found that after treatment with SARME, the convexity from the outside of the bilateral cheek areas to the mouth angle increased, and the middle of the upper lip moved slightly backward, while the outside was unchanged.

MARME can cause changes in soft tissues, including the increase of H angle, the increase of soft tissues from the lower nose to the H line (94).

Future directions and research needs

The above existing studies on the effects of maxillary expansion on the NSD are all retrospective exploratory studies or case series analysis, and lack of prospective studies, which has limitations on the confidence of the results. We found that the maintenance time of expansion was different in these studies. The longest maintenance time was the study of Maspero (46), with a 12-month follow-up, demonstrating the long-term stability of RME to NSD. In addition, only one study (49) followed up the nasal septum of patients after the end of maintenance, and the interval of CBCT scan was the same as that of Maspero (46), which was 12 months. The difference in maintenance time and follow-up time may be one of the reasons why different studies have shown that RME has different effects on NSD improvement. In Aziz’s study (53), the number of people was not matched due to the limitation of sample size. At the same time, no study has classified the severity of NSD to explore the therapeutic effect of RME on NSD with different severity. Further research with a larger sample size is expected in the future.

Given the role of maxillary expansion in improving the structure of the nasal septum and respiratory function, further prospective studies with large sample sizes and long-term follow-up, grouping by the degree of septal deviation and age, will further elucidate the relationship between maxillary expansion and NSD. This will provide stronger evidence support and more precise clinical application guidance for the treatment and prevention of NSD through maxillary expansion.

Conclusions

As a common anatomical variation, severe NSD has no effective treatment in adolescents. Recently, it has been found that early expansion treatment for children and adolescents is an effective method to treat nasal septum. Even if it cannot correct the deviation of the nasal septum, it can also change the nasal and airway structure and improve respiratory-related functions. Therefore, it can prevent and intervene in mouth breathing and help the normal development of nasal septum and jaw (Table 5).

Acknowledgments

Funding: This work was supported by Clinical Research Program of 9th People’s Hospital, Shanghai Jiao Tong University School of Medicine (No. JYLJ202114) and the Project of Biobank from Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine (No. YBKA202202).

Footnote

Reporting Checklist: The authors have completed the Narrative Review reporting checklist. Available at https://fomm.amegroups.com/article/view/10.21037/fomm-24-2/rc

Peer Review File: Available at https://fomm.amegroups.com/article/view/10.21037/fomm-24-2/prf

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://fomm.amegroups.com/article/view/10.21037/fomm-24-2/coif). The authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.

References

1. Mladina R. The role of maxillar morphology in the development of pathological septal deformities. Rhinology 1987;25:199-205. [PubMed]
2. Sazgar AA, Massah J, Sadeghi M, et al. The incidence of concha bullosa and the correlation with nasal septal deviation. B-ENT 2008;4:87-91. [PubMed]
3. Stallman JS, Lobo JN, Som PM. The incidence of concha bullosa and its relationship to nasal septal deviation and paranasal sinus disease. AJNR Am J Neuroradiol 2004;25:1613-8. [PubMed]
4. Atsal G, Demir E, Yildirim O, et al. The Relationship Between Degree of Nasal Septum Deviation With Sinonasal Structures and Variations. J Craniofac Surg 2022;33:e447-9. [Crossref] [PubMed]
5. Magliulo G, Iannella G, Ciofalo A, et al. Nasal pathologies in patients with obstructive sleep apnoea. Acta Otorhinolaryngol Ital 2019;39:250-6. [Crossref] [PubMed]
6. Akoğlu E, Karazincir S, Balci A, et al. Evaluation of the turbinate hypertrophy by computed tomography in patients with deviated nasal septum. Otolaryngol Head Neck Surg 2007;136:380-4. [Crossref] [PubMed]
7. Chen XB, Lee HP, Chong VF, et al. Assessment of septal deviation effects on nasal air flow: a computational fluid dynamics model. Laryngoscope 2009;119:1730-6. [Crossref] [PubMed]
8. Kim SK, Heo GE, Seo A, et al. Correlation between nasal airflow characteristics and clinical relevance of nasal septal deviation to nasal airway obstruction. Respir Physiol Neurobiol 2014;192:95-101. [Crossref] [PubMed]
9. Kawalski H, Spiewak P. How septum deformations in newborns occur. Int J Pediatr Otorhinolaryngol 1998;44:23-30. [Crossref] [PubMed]
10. Saniasiaya J, Abdullah B. Quality of life in children following nasal septal surgery: A review of its outcome. Pediatr Investig 2019;3:180-4. [Crossref] [PubMed]
11. Cashman EC, Farrell T, Shandilya M. Nasal birth trauma: a review of appropriate treatment. Int J Otolaryngol 2010;2010:752974. [Crossref] [PubMed]
12. van der Heijden P, Korsten-Meijer AG, van der Laan BF, et al. Nasal growth and maturation age in adolescents: a systematic review. Arch Otolaryngol Head Neck Surg 2008;134:1288-93. [Crossref] [PubMed]
13. Most SP, Rudy SF. Septoplasty: Basic and Advanced Techniques. Facial Plast Surg Clin North Am 2017;25:161-9. [Crossref] [PubMed]
14. Lee E, Lee SJ, Kim HJ, et al. Incidence of re-deviated nasal septum after septoplasty in adolescent and adult patients. Acta Otolaryngol 2018;138:909-12. [Crossref] [PubMed]
15. Bin Dakhil N, Bin Salamah F. The Diagnosis Methods and Management Modalities of Maxillary Transverse Discrepancy. Cureus 2021;13:e20482. [Crossref] [PubMed]
16. Baccetti T, Franchi L, Cameron CG, et al. Treatment timing for rapid maxillary expansion. Angle Orthod 2001;71:343-50. [PubMed]
17. McNamara JA. Maxillary transverse deficiency. Am J Orthod Dentofacial Orthop 2000;117:567-70. [Crossref] [PubMed]
18. Neyt NM, Mommaerts MY, Abeloos JV, et al. Problems, obstacles and complications with transpalatal distraction in non-congenital deformities. J Craniomaxillofac Surg 2002;30:139-43. [Crossref] [PubMed]
19. Gray LP. Deviated nasal septum. Incidence and etiology. Ann Otol Rhinol Laryngol Suppl 1978;87:3-20. [Crossref] [PubMed]
20. Abou Sleiman R, Saadé A. Effect of septal deviation on nasomaxillary shape: A geometric morphometric study. J Anat 2021;239:788-800. [Crossref] [PubMed]
21. Ramires T, Maia RA, Barone JR. Nasal cavity changes and the respiratory standard after maxillary expansion. Braz J Otorhinolaryngol 2008;74:763-9. [Crossref] [PubMed]
22. Farronato G, Giannini L, Galbiati G, et al. RME: influences on the nasal septum. Minerva Stomatol 2012;61:125-34. [PubMed]
23. Haas AJ. The treatment of maxillary deficiency by opening the midpalatal suture. Angle Orthod 1965;35:200-17. [PubMed]
24. Liu S, Xu T, Zou W. Effects of rapid maxillary expansion on the midpalatal suture: a systematic review. Eur J Orthod 2015;37:651-5. [Crossref] [PubMed]
25. Andrucioli MCD, Matsumoto MAN. Transverse maxillary deficiency: treatment alternatives in face of early skeletal maturation. Dental Press J Orthod 2020;25:70-9. [Crossref] [PubMed]
26. Lima AL, Lima Filho RM, Bolognese AM. Long-term clinical outcome of rapid maxillary expansion as the only treatment performed in Class I malocclusion. Angle Orthod 2005;75:416-20. [PubMed]
27. Martina R, Cioffi I, Farella M, et al. Transverse changes determined by rapid and slow maxillary expansion--a low-dose CT-based randomized controlled trial. Orthod Craniofac Res 2012;15:159-68. [Crossref] [PubMed]
28. Bucci R, D'Antò V, Rongo R, et al. Dental and skeletal effects of palatal expansion techniques: a systematic review of the current evidence from systematic reviews and meta-analyses. J Oral Rehabil 2016;43:543-64. [Crossref] [PubMed]
29. Lo Giudice A, Fastuca R, Portelli M, et al. Effects of rapid vs slow maxillary expansion on nasal cavity dimensions in growing subjects: a methodological and reproducibility study. Eur J Paediatr Dent 2017;18:299-304. [PubMed]
30. Colak C, Aras B, Cheng LL, et al. Effects of rapid and slow maxillary expansion on root resorption: a micro-computed tomography study. Eur J Orthod 2021;43:682-9. [Crossref] [PubMed]
31. Lehman JA Jr, Haas AJ. Surgical-orthodontic correction of transverse maxillary deficiency. Dent Clin North Am 1990;34:385-95. [Crossref] [PubMed]
32. Goldenberg DC, Alonso N, Goldenberg FC, et al. Using computed tomography to evaluate maxillary changes after surgically assisted rapid palatal expansion. J Craniofac Surg 2007;18:302-11. [Crossref] [PubMed]
33. Siqueira DF, Cardoso Mde A, Capelozza Filho L, et al. Periodontal and dental effects of surgically assisted rapid maxillary expansion, assessed by using digital study models. Dental Press J Orthod 2015;20:58-63. [Crossref] [PubMed]
34. Bell WH, Epker BN. Surgical-orthodontic expansion of the maxilla. Am J Orthod 1976;70:517-28. [Crossref] [PubMed]
35. Kayalar E, Schauseil M, Hellak A, et al. Nasal soft- and hard-tissue changes following tooth-borne and hybrid surgically assisted rapid maxillary expansion: A randomized clinical cone-beam computed tomography study. J Craniomaxillofac Surg 2019;47:1190-7. [Crossref] [PubMed]
36. Buck LM, Dalci O, Darendeliler MA, et al. Effect of Surgically Assisted Rapid Maxillary Expansion on Upper Airway Volume: A Systematic Review. J Oral Maxillofac Surg 2016;74:1025-43. [Crossref] [PubMed]
37. Hur JS, Kim HH, Choi JY, et al. Investigation of the effects of miniscrew-assisted rapid palatal expansion on airflow in the upper airway of an adult patient with obstructive sleep apnea syndrome using computational fluid-structure interaction analysis. Korean J Orthod 2017;47:353-64. [Crossref] [PubMed]
38. Lin L, Ahn HW, Kim SJ, et al. Tooth-borne vs bone-borne rapid maxillary expanders in late adolescence. Angle Orthod 2015;85:253-62. [Crossref] [PubMed]
39. Lee KJ, Choi SH, Choi TH, et al. Maxillary transverse expansion in adults: Rationale, appliance design, and treatment outcomes. Seminars in Orthodontics 2018;24. [Crossref]
40. Chun JH, de Castro ACR, Oh S, et al. Skeletal and alveolar changes in conventional rapid palatal expansion (RPE) and miniscrew-assisted RPE (MARPE): a prospective randomized clinical trial using low-dose CBCT. BMC Oral Health 2022;22:114. [Crossref] [PubMed]
41. Korbmacher H, Schilling A, Püschel K, et al. Age-dependent three-dimensional microcomputed tomography analysis of the human midpalatal suture. J Orofac Orthop 2007;68:364-76. [Crossref] [PubMed]
42. Persson M, Thilander B. Palatal suture closure in man from 15 to 35 years of age. Am J Orthod 1977;72:42-52. [Crossref] [PubMed]
43. Angelieri F, Cevidanes LH, Franchi L, et al. Midpalatal suture maturation: classification method for individual assessment before rapid maxillary expansion. Am J Orthod Dentofacial Orthop 2013;144:759-69. [Crossref] [PubMed]
44. Chen S, Wang J, Xi X, et al. Rapid Maxillary Expansion Has a Beneficial Effect on the Ventilation in Children With Nasal Septal Deviation: A Computational Fluid Dynamics Study. Front Pediatr 2021;9:718735. [Crossref] [PubMed]
45. Gray LP. Results of 310 cases of rapid maxillary expansion selected for medical reasons. J Laryngol Otol 1975;89:601-14. [Crossref] [PubMed]
46. Maspero C, Galbiati G, Del Rosso E, et al. RME: effects on the nasal septum. A CBCT evaluation. Eur J Paediatr Dent 2019;20:123-6. [PubMed]
47. Ronsivalle V, Carli E, Lo Giudice A, et al. Nasal Septum Changes in Adolescents Treated with Tooth-Borne and Bone-Borne Rapid Maxillary Expansion: A CBCT Retrospective Study Using Skeletal Tortuosity Ratio and Deviation Analysis. Children (Basel) 2022;9:1853. [Crossref] [PubMed]
48. Gokce G, Veli I, Yuce YK, et al. Efficiency evaluation of rapid maxillary expansion treatment on nasal septal deviation using tortuosity ratio from cone-beam computer tomography images. Comput Methods Programs Biomed 2020;188:105260. [Crossref] [PubMed]
49. Bruno G, Stefani A, Benetazzo C, et al. Changes in nasal septum morphology after rapid maxillary expansion: a Cone-Beam Computed Tomography study in pre-pubertal patient. Dental Press J Orthod 2020;25:51-6. [Crossref] [PubMed]
50. Veloso NC, Mordente CM, de Sousa AA, et al. Three-dimensional nasal septum and maxillary changes following rapid maxillary expansion in patients with cleft lip and palate. Angle Orthod 2020;90:672-9. [Crossref] [PubMed]
51. Jiang M, You M, Wang S, et al. Analysis of Nasal Septal Deviation in Cleft Palate and/or Alveolus Patients Using Cone-Beam Computed Tomography. Otolaryngol Head Neck Surg 2014;151:226-31. [Crossref] [PubMed]
52. Akay G, Eren İ, Karadag Ö, et al. Nasal septal deviation in the unilateral cleft lip and palate deformities: a three-dimensional analysis. Oral Radiol 2021;37:567-72. [Crossref] [PubMed]
53. Aziz T, Wheatley FC, Ansari K, et al. Nasal septum changes in adolescent patients treated with rapid maxillary expansion. Dental Press J Orthod 2016;21:47-53. [Crossref] [PubMed]
54. Kamińska I. Laryngological effects of palatal suture expansion. Ann Acad Med Stetin 2008;54:24-30. [PubMed]
55. Dias RR, Takeshita WM, Sverzut AT, et al. Linear analysis of the nasal septum in patients treated with surgically assisted rapid maxillary expansion. Am J Orthod Dentofacial Orthop 2021;159:71-80. [Crossref] [PubMed]
56. Barrabé A, Meyer C, Bonomi H, et al. Surgically assisted rapid palatal expansion in class III malocclusion: Our experience. J Stomatol Oral Maxillofac Surg 2018;119:384-8. [Crossref] [PubMed]
57. Seeberger R, Kater W, Schulte-Geers M, et al. Surgically assisted rapid maxillary expansion. Effects on the nasal airways and nasal septum. HNO 2010;58:806-11. [Crossref] [PubMed]
58. Landim FS, Freitas GB, Malouf AB, et al. Repercussions of surgically assisted maxillary expansion on nose width and position of septum and inferior nasal conchae. Int J Med Sci 2011;8:659-66. [Crossref] [PubMed]
59. Altug-Atac AT, Atac MS, Kurt G, et al. Changes in nasal structures following orthopaedic and surgically assisted rapid maxillary expansion. Int J Oral Maxillofac Surg 2010;39:129-35. [Crossref] [PubMed]
60. Schwarz GM, Thrash WJ, Byrd DL, et al. Tomographic assessment of nasal septal changes following surgical-orthodontic rapid maxillary expansion. Am J Orthod 1985;87:39-45. [Crossref] [PubMed]
61. Buck LM, Dalci O, Darendeliler MA, et al. Volumetric upper airway changes after rapid maxillary expansion: a systematic review and meta-analysis. Eur J Orthod 2017;39:463-73. [PubMed]
62. Pangrazio-Kulbersh V, Wine P, Haughey M, et al. Cone beam computed tomography evaluation of changes in the naso-maxillary complex associated with two types of maxillary expanders. Angle Orthod 2012;82:448-57. [Crossref] [PubMed]
63. Zeng J, Gao X. A prospective CBCT study of upper airway changes after rapid maxillary expansion. Int J Pediatr Otorhinolaryngol 2013;77:1805-10. [Crossref] [PubMed]
64. Fastuca R, Lorusso P, Lagravère MO, et al. Digital evaluation of nasal changes induced by rapid maxillary expansion with different anchorage and appliance design. BMC Oral Health 2017;17:113. [Crossref] [PubMed]
65. Garib DG, Henriques JF, Janson G, et al. Rapid maxillary expansion--tooth tissue-borne versus tooth-borne expanders: a computed tomography evaluation of dentoskeletal effects. Angle Orthod 2005;75:548-57. [PubMed]
66. DiCosimo C, Alsulaiman AA, Shah C, et al. Analysis of nasal airway symmetry and upper airway changes after rapid maxillary expansion. Am J Orthod Dentofacial Orthop 2021;160:695-704. [Crossref] [PubMed]
67. Altheer C, Papageorgiou SN, Antonarakis GS, et al. Do patients with different craniofacial patterns have differences in upper airway volume? A systematic review with network meta-analysis. Eur J Orthod 2024;46:cjae010. [Crossref] [PubMed]
68. Weissheimer A, Menezes LM, Sameshima GT, et al. Imaging software accuracy for 3-dimensional analysis of the upper airway. Am J Orthod Dentofacial Orthop 2012;142:801-13. [Crossref] [PubMed]
69. Guijarro-Martínez R, Swennen GR. Cone-beam computerized tomography imaging and analysis of the upper airway: a systematic review of the literature. Int J Oral Maxillofac Surg 2011;40:1227-37. [Crossref] [PubMed]
70. Almuzian M, Ju X, Almukhtar A, et al. Does rapid maxillary expansion affect nasopharyngeal airway? A prospective Cone Beam Computerised Tomography (CBCT) based study. Surgeon 2018;16:1-11. [Crossref] [PubMed]
71. Görgülü S, Gokce SM, Olmez H, et al. Nasal cavity volume changes after rapid maxillary expansion in adolescents evaluated with 3-dimensional simulation and modeling programs. Am J Orthod Dentofacial Orthop 2011;140:633-40. [Crossref] [PubMed]
72. Lanteri V, Farronato M, Ugolini A, et al. Volumetric Changes in the Upper Airways after Rapid and Slow Maxillary Expansion in Growing Patients: A Case-Control Study. Materials (Basel) 2020;13:2239. [Crossref] [PubMed]
73. Izuka EN, Feres MF, Pignatari SS. Immediate impact of rapid maxillary expansion on upper airway dimensions and on the quality of life of mouth breathers. Dental Press J Orthod 2015;20:43-9. [Crossref] [PubMed]
74. McNamara JA Jr, Lione R, Franchi L, et al. The role of rapid maxillary expansion in the promotion of oral and general health. Prog Orthod 2015;16:33. [Crossref] [PubMed]
75. Bicakci AA, Agar U, Sökücü O, et al. Nasal airway changes due to rapid maxillary expansion timing. Angle Orthod 2005;75:1-6. [PubMed]
76. Magnusson A, Bjerklin K, Nilsson P, et al. Nasal cavity size, airway resistance, and subjective sensation after surgically assisted rapid maxillary expansion: a prospective longitudinal study. Am J Orthod Dentofacial Orthop 2011;140:641-51. [Crossref] [PubMed]
77. Li Q, Tang H, Liu X, et al. Comparison of dimensions and volume of upper airway before and after mini-implant assisted rapid maxillary expansion. Angle Orthod 2020;90:432-41. [Crossref] [PubMed]
78. Calvo-Henriquez C, Capasso R, Chiesa-Estomba C, et al. The role of pediatric maxillary expansion on nasal breathing. A systematic review and metanalysis. Int J Pediatr Otorhinolaryngol 2020;135:110139. [Crossref] [PubMed]
79. Lindemann J, Keck T, Wiesmiller K, et al. Nasal air temperature and airflow during respiration in numerical simulation based on multislice computed tomography scan. Am J Rhinol 2006;20:219-23. [Crossref] [PubMed]
80. Iwasaki T, Papageorgiou SN, Yamasaki Y, et al. Nasal ventilation and rapid maxillary expansion (RME): a randomized trial. Eur J Orthod 2021;43:283-92. [Crossref] [PubMed]
81. Ottaviano G, Maculan P, Borghetto G, et al. Nasal function before and after rapid maxillary expansion in children: A randomized, prospective, controlled study. Int J Pediatr Otorhinolaryngol 2018;115:133-8. [Crossref] [PubMed]
82. Xiao W, Liu S, Lu Y, et al. Computational Fluid Dynamics Analysis of Nasal Airway Changes after Treatment with C-Expander. Appl Bionics Biomech 2021;2021:8874833. [Crossref] [PubMed]
83. Fastuca R, Perinetti G, Zecca PA, et al. Airway compartments volume and oxygen saturation changes after rapid maxillary expansion: a longitudinal correlation study. Angle Orthod 2015;85:955-61. [Crossref] [PubMed]
84. Cappellette M Jr, Nagai LHY, Gonçalves RM, et al. Skeletal effects of RME in the transverse and vertical dimensions of the nasal cavity in mouth-breathing growing children. Dental Press J Orthod 2017;22:61-9. [Crossref] [PubMed]
85. Gürler G, Akar NK, Delilbaşı Ç, et al. Skeletal changes following surgically assisted rapid maxillary expansion (SARME). Eur Oral Res 2018;52:94-8. [PubMed]
86. Nada RM, van Loon B, Schols JG, et al. Volumetric changes of the nose and nasal airway 2 years after tooth-borne and bone-borne surgically assisted rapid maxillary expansion. Eur J Oral Sci 2013;121:450-6. [Crossref] [PubMed]
87. Venezia P, Nucci L, Moschitto S, et al. Short-Term and Long-Term Changes of Nasal Soft Tissue after Rapid Maxillary Expansion (RME) with Tooth-Borne and Bone-Borne Devices. A CBCT Retrospective Study. Diagnostics (Basel) 2022;12:875. [Crossref] [PubMed]
88. Truong CT, Jeon HH, Sripinun P, et al. Short-term and long-term effects of rapid maxillary expansion on the nasal soft and hard tissue. Angle Orthod 2021;91:46-53. [Crossref] [PubMed]
89. Aras I, Olmez S, Akay MC, et al. The effects of maxillary expansion on the soft tissue facial profile. J Istanb Univ Fac Dent 2017;51:1-10. [Crossref] [PubMed]
90. Badreddine FR, Fujita RR, Alves FEMM, et al. Rapid maxillary expansion in mouth breathers: a short-term skeletal and soft-tissue effect on the nose. Braz J Otorhinolaryngol 2018;84:196-205. [Crossref] [PubMed]
91. Berger JL, Pangrazio-Kulbersh V, Thomas BW, et al. Photographic analysis of facial changes associated with maxillary expansion. Am J Orthod Dentofacial Orthop 1999;116:563-71. [Crossref] [PubMed]
92. Ramieri GA, Nasi A, Dell'acqua A, et al. Facial soft tissue changes after transverse palatal distraction in adult patients. Int J Oral Maxillofac Surg 2008;37:810-8. [Crossref] [PubMed]
93. Nada RM, van Loon B, Maal TJ, et al. Three-dimensional evaluation of soft tissue changes in the orofacial region after tooth-borne and bone-borne surgically assisted rapid maxillary expansion. Clin Oral Investig 2013;17:2017-24. [Crossref] [PubMed]
94. Shetty A, Ratti S, Nakra P, et al. Evaluation of Soft Tissue and Airway Changes in Individuals Treated with Mini-Implant Assisted Rapid Palatal Expansion (MARPE). J Long Term Eff Med Implants 2022;32:7-18. [Crossref] [PubMed]