The primary aim of this study was to investigate and compare perceived pain intensity and oral health–related quality of life (OHRQOL) results during the activation phase of rapid maxillary expansion (RME), with tooth-borne and bone-borne devices. In addition, a secondary aim of this study was to evaluate the correlation between pain scales and the shortened Oral Health Impact Profile (OHIP-14) questionnaire.
Thirty-six subjects (16 girls and 20 boys) with a mean age of 12.3 years (standard deviation, 0.82 years) were randomized into 2 groups. Group A received treatment with hyrax appliance, and group B received a computer-guided skeletal RME appliance. The same type of expansion screw and screw activation or expansion protocol were used. Two rating scales were used to assess the subject’s pain during the activation phase of RME: a Graphic Rating Scale for Pain (GRS) and the Wong-Baker Faces Pain Scale (FPS). The OHIP-14 was used to evaluate the impact of RME on OHRQOL before the beginning of the treatment at day 3 and day 7 follow-ups. Painkillers were forbidden during the active phase of RME. Descriptive statistics, Student t test, and Pearson correlation were used. Significance was set at P ≤0.05.
A total of 36 subjects, divided into 2 groups, were treated in the study. Regarding the level of pain, the Student t test showed statistically significant higher pain in group B—although only on the first day of screw activation (GRS, P = 0.01; FPS, P <0.01). For the following days, there were no significant differences in pain levels between groups. The OHIP-14 showed no statistically significant difference at baseline ( P = 0.32) and day 3 ( P = 0.88) and day 7 ( P = 0.85) follow-ups between the 2 groups. The Pearson correlation coefficient showed a statistically significant association between the 2 different scales of pain (GRS and FPS) but not a statistically significant correlation between GRS and FPS scales and OHIP-14.
A higher perceived pain intensity in the patients treated using a bone-borne computer-guided skeletal RME appliance was limited to the first day of screw activation. There were no statistically significant differences between the 2 types of treatment in terms of their impact on OHRQOL and no statistically significant correlation between pain scales and the OHIP-14 questionnaire.
Pain levels are comparable using tooth-borne or bone-borne computer-guided appliances.
After the first day of expansion, no difference in OHRQOL was found for 2 types of treatment.
Both types of appliances are well tolerated by the subjects during rapid maxillary expansion.
There is no significant correlation between pain scales and the OHIP-14 questionnaire.
Rapid maxillary expansion (RME) is an ordinary orthodontic treatment used to correct a maxillary arch constriction and/or a transverse discrepancy between the maxillary and mandibular jaws (posterior crossbite) by opening the midpalatal suture. This procedure is widely used in primary, mixed, or permanent dentition. The hyrax appliance is the most common type of RME device. It is a fixed metal appliance with an expansion screw that is attached to either 2 or 4 teeth. The expansion screw is turned with a key and is usually activated from 1 to 3 times daily, depending on the activation protocol for about 2-4 weeks. Single activation of screw generates approximately 3-10 pounds of force. RME should produce dentofacial orthopedics forces and minimize orthodontic movement; however, a systematic review showed that the dentoalveolar effects in terms of molar tipping and alveolar bending account for over 50% of the total effects. To minimize these dental side effects, which likely increase the risk of relapse, , skeletally-anchored RME appliances (ie, bone-borne appliances) have been introduced, and because of computer-aided design and computer-aided manufacturing technological innovations, it is possible to guide miniscrew insertion and to apply the skeletal appliance concurrently. , Although earlier studies showed that young patients have a good tolerance of the insertion of miniscrews, since the introduction of skeletally-anchored RME appliances, few studies have explored the pain intensity and discomfort with tooth-borne as compared with bone-borne RME appliances. Clinicians using RME procedures have indicated that children frequently report pain during the expansion phase. Pain is dependent upon such factors as age, sex, individual pain threshold, and the magnitude of force applied. , , Although pain and discomfort are well-known side effects of orthodontic treatment with fixed appliances, few studies have investigated the association between pain and RME procedures. Furthermore, no study has investigated the association between the impact of oral health–related quality of life (OHRQOL) and the RME method. Pain scales are typically visual methods that allow a systematic record of the pain, its intensity, and other symptoms. They are often based on cartoons or numbers. These scales can be self-reported verbal rating scales and can help to obtain a better diagnosis and treatment for pain. “Oral Health,” instead, is not only influenced by the absence or presence of pain, but it is the functional, social, and psychological well-being of people. Therefore, it would be useful to evaluate both the pain and the self-perception effect on OHRQOL. Measuring OHRQOL requires the use of psychometric scales that favor the evaluation of plausibility of explanatory theoretical models. One of the most commonly used instruments for studying the effect of oral health with this approach is the Oral Health Impact Profile (OHIP)—designed to assess disabilities, dysfunctions, and discomfort attributed to oral conditions. OHIP-14 is the short-form of the instrument and is considered a good indicator to capture the perceptions and feelings of patients about their oral health and expectations regarding treatment and dental services. ,
The primary aim of this study was to investigate and compare the perceived pain intensity and the OHRQOL during the activation phase of RME, with tooth-borne (hyrax appliance) and bone-borne (computer-guided skeletal RME appliance). The secondary aim was to evaluate the correlation between pain scales and the OHIP-14 questionnaire.
It was hypothesized that there were no differences between these 2 RME treatment modalities regarding the pain and OHRQOL. Moreover, it was hypothesized that there is no correlation between pain scales and OHIP-14.
Material and methods
This parallel cohort study was conducted at the Department of Orthodontics of Sapienza University of Rome between January 2019 and January 2020. The clinical investigation was conducted in accordance with the ethical principles of the World Medical Association Declaration of Helsinki. The parents or guardians were informed of the content, risks, and benefits of the study, and written consent was obtained. The investigation was independently reviewed and approved by the local ethics committee (# 5951).
Eligibility criteria were as follows: (1) white children in late mixed dentition or permanent dentition, (2) unilateral or bilateral transverse maxillary deficiency of at least 8 mm, (3) no previous orthodontic treatment, (4) good oral hygiene, and (5) no systemic syndrome involved.
This study included 2 groups of subjects according to the type of expander used: the tooth-borne hyrax appliance group (group A) and the bone-borne computer-guided expander appliance group (group B). A randomization sequence was created using Clinstat statistical software (Martin Bland, York, United Kingdom) for the treatment allocation of the 2 groups. To date, there are no similar studies in the literature; therefore, it was not possible to perform a sample size calculation. In group A, the tooth-borne expander (hyrax appliance) was designed with the band on the maxillary first molars; in group B, the bone-borne expander was a miniscrew-supported RME appliance with 4 miniscrews inserted both in paramedian and parapalatal position of palatal vault. To ensure a minimally-invasive miniscrew insertion, we created a surgical guide (Easy Driver; Uniontech Orthodontic Lab, Parma, Italy) using a 3-dimensional printer (Stratasys OrhoDesktop; Stratasys, Rehovot, Israel). The appropriate miniscrews insertion sites were based on 3-dimensional images created by the fusion of cone-beam computed tomography and dental digital model images. The length and diameter of the self-drilling titanium miniscrews used were predetermined in the planning phase. Both the miniscrews and the RME device were inserted at the same time. No unexpected events and/or complications were recorded during miniscrews insertion. In both groups, the expansion screw was activated at the same time of device insertion; the same type of expansion screw (10 mm; hyrax click; Dentaurum, Bologna, Italy) and expansion protocol were used. The expansion screw was activated by 4 quarter-turns on the first day and by 3 quarter-turns per day in the active phase of treatment (0.20 mm per turn, 0.6 mm daily) until an 8 mm of screw opening was achieved. All patients in both groups were treated by the same clinical research (F.A.).
All patients received 3 different forms: (1) Graphic Rating Scale for Pain (GRS), (2) the Wong-Baker Faces Pain Scale (FPS), and (3) OHIP-14 questionnaire.
The first 2 rating scales were used to assess the patient’s pain, whereas the Italian version of the OHIP-14 was used to evaluate the impact of RME on OHRQOL. The GRS is a visual analog scale in which a numerical scale (from 0 to 10) is added; the GRS consists of a straight line with the endpoints defining extreme limits such as “no pain at all” and “pain as bad as it could be” ( Fig 1 , A ). The patient is asked to mark his pain level on the line between the 2 endpoints. The distance between “no pain at all” and the mark then defines the subject’s pain. The FPS consists of a series of faces with expressions of increasing distress. The FPS was developed to assist children in rating pain. This scale shows 6 faces in different degrees of distress. This scale starts at 0 with the statement “No Hurt” under a face with a broad smile and continues to 5 with the statement “Hurts worst” and a face with a frown and tears ( Fig 1 , B ).
The OHIP-14 questionnaire contains 14 questions that represent 7 dimensions of OHRQOL: functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. These questions retain the original conceptual dimensions contained in the full OHIP, and thus, this instrument is considered useful for quantifying levels of impact on well-being in settings in which only a limited number of questions can be administered ( Fig 1 , C ).
Verbal instructions were given to the parent or guardian and children about how to assess pain and complete the questionnaire correctly. Painkillers were forbidden during the active phase of RME. In case of severe pain, the patient was instructed to contact the clinician for a painkiller prescription. In no case did this occur.
The corresponding amount of pain (GRS and FPS scales) was filled in by subjects every day, 15 minutes after the screw activation of RME. The OHIP-14 self-administered questionnaire was completed by the subject before the beginning of treatment (baseline) at day 3 and day 7 follow-ups. Responses were indicated on an ordinal 5-point adjectival scale: 0 = never, 1 = hardly ever, 2 = occasionally, 3 = fairly often, and 4 = very often. The summary score of the OHIP-14 items in which a higher score indicating a stronger negative influence characterizes the OHRQOL.
Descriptive statistics, including mean values and standard deviations, were used for the statistical analysis. A database was created using Excel (Microsoft, Redmond, Wash), with appropriate checks to identify errors. The Student t test was used to evaluate statistically significant differences among the levels of pain between the 2 groups in the subsequent days of RME activation and when there were statistically significant differences between the effect of the 2 different RME appliances on OHRQOL at the beginning of treatment (baseline) and day 3 and day 7 follow-up. The Pearson correlation was used to determine the concordance between the pain scales scores (GRS and FPS) and to determine if there was a statistically significant correlation among the pain scales (GRS and FPS) and the OHIP-14. Values of P ≤0.05 were considered significant.
Two hundred subjects were assessed for eligibility. On the basis of the inclusion criteria, 166 subjects were not eligible. From the 38 eligible, 2 subjects did not give their consent to the treatment and were excluded after being informed about the possible complications and the need for periodic clinical checks. A total of 36 subjects were included in the study and treated (16 females [44%] and 20 males [56%]). The age of the study population ranged from 10.1 years to 13.6 years (mean, 12.3 years; standard deviation, 0.82 years). The study population was randomly allocated into 2 groups (group A and group B). Eighteen subjects (mean age, 12.2 years; male-to-female ratio, 10:8) were assigned to receive treatment with hyrax appliance (group A), and 18 subjects (mean age, 12.3 years; male-to-female ratio, 11:7) were treated with computer-guided miniscrew-supported RME appliance (group B). Baseline characteristics, including age and sex, were similar in the 2 groups ( Table I ). No subject dropped out of the study, and all subjects completed the questionnaires. No data were missing for each variable of interest.
With regard to the level of pain, the Student t test showed statistically significantly higher pain in group B on the first day of screw activation only ( Table II ). For the following days, there were no significant differences in pain levels between groups, although subjects with miniscrews appliance generally scored higher mean pain levels. ( Figs 2 , A and B ). Concerning the OHIP-14, the paired comparison between group A and group B showed no statistically significant difference at the baseline ( P = 0.32), day 3 ( P = 0.88), and day 7 ( P = 0.85) follow-ups. A higher deterioration in OHRQOL was observed at the day 3 follow-up, whereas a modest deterioration was recorded at the day 7 follow-up ( Table III ). The Pearson correlation coefficient measured a statistically significant association between the 2 different scales of pain (GRS and FPS during the days of screw activation in both groups [ Tables IV and V ]). The Pearson test showed no statistically significant correlation between GRS and OHIP-14 at the day 3 (correlation coefficient, 0.25; P = 0.39) and at the day 7 (correlation coefficient, 0.30; P = 0.39) follow-ups. There was no statistically significant correlation between FPS and OHIP-14 at the day 3 (correlation coefficient, 0.46; P = 0.17) and day 7 (correlation coefficient, 0.39; P = 0.25) follow-ups.
|Pain scale||Group A (mean)||Group B (mean)||P value|