INTRODUCTION

Patient-centered care is a concept that has emerged in recent years and is becoming an important goal in systems providing healthcare. In addition to empowering patients to be active participants in their care and involving them in decision-making, the main elements of this concept are to understand patients' specific needs, expectations, experiences, emotional well-being, and satisfaction with overall quality of care given.¹ In turn, this should positively reflect on patient compliance and lead to a more successful treatment outcome.

Posterior crossbite is one of the most frequently observed malocclusions, particularly during the primary and mixed dentition stages.² Maxillary expansion is usually the treatment of choice that can be accomplished either by rapid maxillary expansion (RME) or slow maxillary expansion (SME). The use of either method depends on individual clinician preferences and experiences, malocclusion type, and patient age. RME produces orthopedic effects in a short time by generating forces greater than those required for orthodontic tooth movement, leading to changes in the circumaxillary suture system, especially the midpalatal suture.³ However, RME is not without complications, which may include bite opening, microtrauma of the midpalatal suture, root resorption, excessive tipping of teeth, and relapse.⁴ As a result, some clinicians prefer SME as it produces small forces over a longer period, which allows better adaptability of supporting tissues, minimizing future relapse.⁵

Many studies have previously reported on patients' negative experiences with various types of orthodontic appliances.^6,7 However, few studies evaluated subjective symptoms of patients undergoing expansion with either method, rapid or slow.^8–10 In addition to pain, some degree of jaw function impairment, such as difficulty in mastication, swallowing, and speaking during the first few days were reported as main side effects.^9,11

Although several studies compared between the methods of SME and RME in relation to dental and skeletal effects,¹² no prospective study compared between methods with respect to patients' negative experiences. Such information would provide greater insight for clinicians on what to expect when choosing either alternative and also aid them in informing patients about what to expect during treatment.

Therefore, the present study aimed to compare perceived pain/discomfort and jaw function impairment during the first 4 weeks with either SME using quadhelix or RME using conventional hyrax. The null hypothesis was that there would be no differences between the two methods.

MATERIALS AND METHODS

This study is presented in accordance with the Transparent Reporting of Evaluations with Nonrandomized Designs statement (TREND).¹³

Participants

Patients were consecutively recruited and alternately allocated. The first patient was allocated to the quadhelix group (QG) for SME (Figure 1) and the next patient was assigned to the hyrax group (HG) for RME (Figure 2). This allocation sequence was repeated until reaching the required number of patients. Patient allocation was done by a single investigator (FA) who was also involved in treatment of the patients at the Orthodontics and Paediatric Dentistry Sections, Hamad Dental Center, Hamad Medical Corporation, Doha, Qatar.

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All patients met the following inclusion criteria: uni- or bilateral crossbite with constricted maxilla in which at least 5 mm of expansion was required (intermolar width ≤ 31 mm measured from the gingival margin),¹⁴ no or mild/moderate crowding, mixed or permanent dentition stages (≤ 15 years old) with upper permanent first premolar fully erupted. Patients with craniofacial deformations, unfit and/or taking medications, periodontal diseases, and history of orthodontic treatment or in active orthodontic treatment were excluded.

Interventions

Two experienced orthodontists (FA and NA) treated all patients in both groups according to a preset standardized protocol, following that which was given in the written informed consent. In the QG group, a fixed quadhelix was used which, before cementation, was activated 1 molar width posteriorly and 1 premolar width anteriorly as described by Donohue et al.⁸ At the first follow-up visit (after 6 weeks), the same activation protocol was accomplished and this cycle was repeated until overexpansion was achieved (when the mesiopalatal cusps of the maxillary first molars were in contact with the buccal cusps of the mandibular first molars). In the HG group, a four-band hyrax was cemented (Dentaurum, Ispringen, Germany). For activation, parents were instructed to turn the screw twice/d (0.25 mm/turn, 0.5 mm/d) for 10 to 14 days until overexpansion was achieved as described for the QG. The hyrax was kept in place for a minimum of 5 months to allow for expansion stabilization.

After insertion and activation of the appliances, patients in both groups were given a questionnaire and were asked to complete it at home after 4 hours, every day for the following 6 days, at 2 weeks, and after 4 weeks. The questionnaire included 11 items that were inspired from previous studies with changes in wording and ratings for a few items to improve completion rates (Table 1).^8,15 Pretesting of the questionnaire was conducted before commencing the study in a group of five children who needed maxillary expansion with either appliance. No difficulties or issues were reported. Questions 1 to 4 concerned pain from teeth, tongue, and palate. The first three questions were graded using a visual analogue scale (VAS) with the end phrases “no pain” and “worst pain imaginable.” Question 4 had a binary response (Yes/No). Questions 5 to 9 evaluated jaw function impairment (mastication, swallowing, speaking, yawning, and laughing). All were graded with VAS except questions 8 and 9, which had binary responses (Yes/No). Questions 10 and 11, which had binary responses (Yes/No), asked about analgesic consumption and headache experience, respectively. Instructions on how to complete the questionnaire were given. Patients were reminded daily via calls to complete the questionnaire. For the VAS, patients were asked to mark a vertical line along the line corresponding to their perceived experience. The VAS was measured by an independent investigator not involved in the study to the nearest 0.5 mm using a standard 100-mm metric ruler from the left end to the mark placed by the patient, Intraclass correlation (ICC) was conducted to assess reliability of measurements by remeasuring VAS scores after 2 weeks for 10 randomly selected patients (ICC = 0.98).

Table 1. Questionnaire Used in the Study

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RESULTS

Participant Flow

The flow of participants is shown in Figure 3.

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Baseline Data

No significant differences were found between the groups with respect to baseline characteristics. The mean ages (SD) for the QG and the HG were 12.89 (1.5) and 12.75 (1.4) years, respectively. The majority of patients were females in both groups (Table 2).

Table 2. Baseline Characteristics of Patients in Both Groups

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Outcomes

Pain intensity.

Pain intensity from teeth in the QG and HG peaked at day 2 and at 4 hours, respectively. In both groups, pain intensity started to decrease significantly following day 3 (Figure 4). Except at 4 hours, there were no significant differences in pain between the groups at other time points (Table 3). Regarding pain from tongue and palate, patients' assessments were generally low (median < 30). HG reported significantly higher pressure from the palate at 4 hours. However, there were no significant differences between the groups at other time points (Table 3).

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Table 3. Median and Interquartile Range of VAS Scores for Pain and Functional Jaw Impairment Items in Both Groups at Each Time Point

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More patients in the HG reported having ulcerations on their tongues than the QG (53% and 30%, respectively); however, this difference was not statistically significant (P = .06).

There were no effects of age, gender, and malocclusion class on any outcomes investigated.

Jaw function impairment.

Generally, patients in the HG reported severe difficulty in mastication that peaked at 4 hours, while patients in the QG reported moderate to severe difficulty that peaked at day 2. The difference between the groups was significant only at 4 hours (Table 3). In both groups, difficulty in mastication decreased significantly at day 5 (Figure 5).

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Patients in the HG reported significantly greater difficulty in swallowing (moderate to severe) than the QG at 4 hours and for the following 6 days (Table 3). In the QG, difficulty in swallowing decreased significantly after day 4, while in the HG, it decreased significantly at day 7 (Figure 5).

Speech difficulty scores were low in both groups and almost disappeared after day 4 (Figure 5). Except for two patients in the HG and one patient in the QG, no patient reported difficulty in yawning (question 8). No patient in either group reported difficulty laughing (question 9).

Analgesic Consumption

Eight patients (29.6%) in the QG and 6 patients (21.4%) in the HG consumed analgesics during the study period (P = .349) (Table 4). All except one patient in the QG and two patients in the HG consumed analgesics one time only on day 2. There was no effect of this variable on the investigated outcomes.

Table 4. Analgesic Consumption in Both Groups

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DISCUSSION

This was the first prospective study to compare perceived pain and jaw function impairment between SME using quadhelix and RME using conventional hyrax. In addition to having successful biological effects, it is also necessary to evaluate patient experiences and any side effects due to treatment. This in turn can aid in shaping the process of informed consent and prepare patients to cope with any negative experiences.

In this study, the VAS was used in most of the questions to rate patient experiences, which is known to be simple, sensitive, and reliable.¹⁷ Although some modifications were made from the original questionnaires used elsewhere,^8,15 these changes were unlikely to affect the validity of the current results as the outcomes being investigated were not psychosocial constructs that necessitated revalidation. Pain assessment in the orthodontic literature is not standardized, with variations in methods of assessment often used with or without pretesting.¹⁸ Here, pretesting of the questionnaire was conducted with no reported issues or difficulties.

Except at 4 hours at which time patients in the HG reported significantly higher pain intensity from the teeth, there were no significant differences between the groups at other time points. In the QG, pain from the teeth peaked at day 2 before decreasing significantly the following day (day 3). This finding was similar to a previous study that compared the quadhelix with another appliance for SME.⁸ Almost the same pattern was found in the HG; however, pain intensity peaked at 4 hours. Although the levels of pain intensity reported in the HG were similar to another study,¹⁹ other studies found lower levels of pain intensity with RME based on VAS scores.¹⁵ This could be attributed to the relatively higher mean age of both groups in the present study. It was reported that younger children were more likely to cope with pain better.¹⁷ Differences in sampling procedures or pain assessment methods could be another reason.

It is well known that RME produces heavy forces at the midpalatal suture in which an inflammatory-like reaction is created that will lead to pain in the form of pressure.¹⁵ Here, the level of pressure in the palate was relatively low in both groups and patients in the HG reported significantly higher pressure at 4 hours only. After that, pressure started to dissipate on subsequent days. This finding was in agreement with other reports that evaluated pain due to pressure in the palate with RME.^11,15 SME caused less discomfort in the palate, as the mechanism of action is different from RME, with less stress exerted on the midpalatal suture. In both groups, the level of pain from the tongue was low, although a considerable number of patients reported having ulcerations on their tongue. A possible reason was that ulcerations on the tongue could be more tolerable than on other non-keratinized soft tissues in the oral cavity.

Similar to other studies that used expansion appliances,^8,11,15 patients reported extreme difficulty in mastication during the first 2 days. Subsequently, they gradually started to adapt on the following days until there was no impact remaining after 1 week.

One of the most important findings of this study was the extreme difficulty in swallowing that patients experienced in the HG compared to the QG. This started after hyrax cementation and lasted the following 6 days until patients adapted at day 7. This finding could be attributed to the reduction in the intraoral space due to the bulkiness of the hyrax compared to the quadhelix. As a result, tongue movements were restricted that negatively affect food bolus movements during the second stage of swallowing.²⁰ Regarding speech difficulty, patients in the HG group reported significantly more difficulty than the QG. However, difficulty scores were generally low in both groups. Again, the bulkiness of the hyrax could restrict the tongue during creation of speech sounds. It is worth mentioning that swallowing and speech difficulties with both appliances were evaluated in a previous retrospective study.⁹ However, it was not possible to make comparisons with the present study due to unclear reporting and methodological limitations. Additionally, retrospective studies are prone to recall bias.

There was no significant difference in analgesic consumption between the groups. Analgesic consumption was low in both groups compared to other forms of orthodontic treatment.¹⁶ This finding was similar to another study that compared between two different types of RME.¹⁵ Contrary to a few reports,¹⁵ there was no effect of age on pain from the teeth or palate. As explained earlier, this could have been due to the older mean age of the present sample compared to other studies that recruited patients younger than 10 years old who perceived less pain and have less interdigitation of the midpalatal suture, meaning less pain and pressure.^15,17 Not including enough younger patients might have masked the effect of age. The majority of patients in both groups were females, which reflected the actual situation in the clinic. This might explain the absence of gender correlation with the investigated outcomes.

CONCLUSIONS

• Except at 4 hours, pain from teeth and pressure in the palate were comparable in both groups and the intensity started to decrease significantly after 2 to 3 days.

• Compared to QG, patients in the HG experienced extreme and significantly more difficulty in swallowing, which lasted for 6 days.

• Speech was minimally affected in both groups.

• Overall, both appliances were well tolerated after 1 week of treatment and the decision to use either appliance could be based on factors not related to patient experiences.