Comparison of the Perception of Pain during Fixed Orthodontic Treatment with Metal and Ceramic Brackets.

INTRODUCTION: Pain is experienced by patients during various fixed orthodontic procedures such as placement of separators, insertion of arch wire and its activations, orthopedic appliances such as headgear, and debonding of the appliance. This study was formulated with the background that the level of pain sensation differs between conventional metal and ceramic brackets, arch wire being the same.
MATERIALS AND METHODS: The sample comprised 40 patients. The patients were separated into two groups: Group A (metal brackets) and Group B (ceramic brackets). In Group A, the brackets were bonded with 0.022" conventional stainless steel brackets (Unitek Gemini, 3M, Monrovia, California). In Group B, the brackets were bonded with ceramic brackets (Unitek Gemini Clear Brackets, 3M, Monrovia, California). The bonding of the brackets was carried out according to the conventional etching, priming, and curing technique. A 0.016" NiTi (nickel titanium) arch wire was used as the first arch wire. The intensity of pain was documented in a figure containing two 100-mm visual analog scales (VASs).
RESULTS: The level of pain reduced in intensity in due course. During 1 month, VAS scores increased at the end of day 1 (24 h) for the metal and ceramic group. The pain then decreased for up to 5 days. The average pain intensity reached 4.44 in the ceramic group, whereas it was 2.7 in the metal group for the upper anterior region. It decreased up to 1 in the ceramic and 0.22 in the metal group.
CONCLUSION: Patients bonded with ceramic brackets experienced a higher and more severe pain of longer duration than individuals treated with conventional brackets.

INTRODUCTION

During fixed orthodontic treatment, the patients complain of pain, which is a concern for the patients as well as the orthodontists.[12] The pain during orthodontic treatment is related to age, sex, pain threshold, the level of force application, emotional status, and past pain experiences.[34567] However, this important clinical area of pain in dentistry is not researched much as is evident from the lack of publications.

The fixed orthodontic procedures, which produce pain, are placement of separators, arch wires, orthopedic appliances, and various debonding procedures. The level of pain, which is produced by fixed orthodontic appliances, is more compared to other orthodontic appliances, and there exists a slight association between the level of force and the experience of pain.

After bonding of fixed orthodontic appliances, the patients are anxious and usually describe and feel pain, tension, pressure, and soreness of the teeth. We as orthodontists tend to explain the patient that there might be a little uneasiness related to treatment methods. However, orthodontists must use their best professional judgment to assess each case individually and select an appropriate treatment modality (pharmacological and non-pharmacological) based on pain threshold level of an individual.[8]

Following banding/bonding of fixed orthodontic appliances, there is a feeling of pain experienced by patients, and this has been associated with the release of various inflammatory cytokines.[91011121314] Review of literature suggests that various orthodontic methods will diminish the proprioceptive and perceptive abilities of the patients for up to 4 days. Several other studies stated that pain was significant during the first 2 days after bonding[251516] although it reverted to baseline after 7 days.[25161718]

The aim of this study was to compare any differences in the level of pain experienced in patients bonded with metal and ceramic brackets.

MATERIALS AND METHODS

The sample comprised 40 patients who were about to start fixed orthodontic treatment in the Department of Orthodontics, Kalinga Institute of Dental Sciences, Bhubaneswar, Odisha, India. Ethical clearance was obtained from the institutional ethics committee with IEC approval no. of KIMS/KIIT/IEC/112/2017. Informed consent was obtained from each patient before starting the study.

The patients who were included in the study had crowding in upper and lower arches and with all permanent teeth erupted, except for the third molars.

The patients were grouped into two groups:

Group A (metal brackets)

Group B (ceramic brackets)

In Group A, the brackets were bonded with 0.022” conventional stainless steel brackets (Unitek Gemini 3M, Monrovia, California).

In Group B, the brackets were bonded with ceramic brackets (Unitek Gemini Clear Brackets, 3M, Monrovia, California).

The treatment was carried out by a single orthodontist. The brackets were bonded according to the conventional etching, priming, and curing technique. A 0.016” NiTi arch wire was used as the initial arch wire, which was ligated in all bracket slots. Elastic modules (Ligature ringlet, RMO, Denver, Colorado) were used for ligation in both the metal and ceramic brackets. During the entire study, the patients were advised not to make use of any analgesics or anti-inflammatory drugs.

The severity of pain was recorded in a form containing two 100-mm visual analog scales (VASs).[181920] Forms were filled up by the patient at 4th h, 24th h, 2nd, 3rd, 4th, and 5th day in the morning, immediately after they got up. The VAS ranged from “no pain” to the “worst possible pain.”

The patients were instructed to document the existence of pain (yes/no), its intensity as recorded on a VAS (“no pain” to the “highest possible pain”), the uniqueness of the pain, and the use of pain killers. The nature of pain was indicated with yes/no reactions for four descriptions according to the McGill Pain Questionnaire.[21]

During the period of the study, treatment was limited to rebonding any debonded brackets, replacing modules or ligatures if lost, and repositioning of the arch wire to the slots and midline if there was any slippage.

RESULTS

The amount of pain reduced in intensity eventually. During 1 month of treatment, VAS scores peaked at the end of day 1 (24 h) for the metal and ceramic group. The pain then decreased for up to 5 days. The average pain intensity reached 4.44 in the ceramic group, whereas it was 2.7 in the metal group for the upper anterior (UA) region as shown in Table 1. It decreased up to 1 in the ceramic and 0.22 in the metal group. The pain intensity started from 2.11 in both the metal and ceramic groups in the lower anterior (LA) region and decreased the same way as in the UA region as shown in Tables 2 and 3 and Figures 1 and 2. The VAS scores were lesser in the LA and upper posterior (UP) as compared with the UA region. The metal group of patients did not report any pain in the lower posterior (LP) region, whereas the VAS scores for the ceramic group ranged from 1.5 in the 4th h to almost 0 in the 5th day as shown in Tables 4 and 5 and Figures 3 and 4. A statistical significant difference was observed on the 3rd day for the UA region.

Table 1

Initial pain between metal and ceramic brackets

Initial pain
	1st h	2nd h	3rd h	4th h	5th h	6th h
Metal	1 (11.1%)	2 (22.2%)	0	2 (22.2%)	0	1 (11.1%)
Ceramic	2 (22.2%)	1 (11.1%)	0	3 (33.3%)	0	1 (11.1%)
P value (chi-square)	0.52	0.52	0	0.59	0	0.5

Table 2

Visual analog scale pain scores in upper anterior region

VAS pain persists in upper anterior region
	4th h	24th h	2nd day	3rd day	4th day	5th day
Metal	2.14 ± 2.11	2.7 ± 2.2	2.61 ± 2.31	1.95 ± 1.67	0.89 ± 1.67	0.22 ± 0.67
Ceramic	2.98 ± 2.94	4.44 ± 2.78	4.11 ± 2.61	3.33 ± 1.33	2.11 ± 0.89	1.00 ± 1.57
P value (ANOVA test)	0.59	0.15	0.105	0.04	0.12	0.93

ANOVA = analysis of variance, VAS = visual analog scale. P<0.05 statistical significance

Table 3

Visual analog scale pain scores in lower anterior region

Lower anterior
	4th h	24th h	2nd day	3rd day	4th day	5th day
Metal	2.11 ± 2.41	2.62 ± 2.32	2.11 ± 2.33	1.33 ± 1.73	0.89 ± 1.33	0.22 ± 0.67
Ceramic	2.00 ± 2.58	3.67 ± 2.65	3.44 ± 2.11	2.78 ± 1.13	2.11 ± 1.96	1.00 ± 1.58
P value (ANOVA test)	0.922	0.43	0.29	0.15	0.12	0.19

ANOVA = analysis of variance

Figure 1

Graph for visual analog scale pain scores of upper anterior region (blue: ceramic, red: metal)

Figure 2

Graph for visual analog scale pain scores of lower anterior region (blue: ceramic, red: metal)

Table 4

Visual analog scale pain scores in upper posterior region

Upper posterior
	4th h	24th h	2nd day	3rd day	4th day	5th day
Metal	0.89 ± 1.74	1.00 ± 2.00	1.00 ± 2.00	0.78 ± 1.56	0.56 ± 1.23	0
Ceramic	0.56 ± 1.66	1.67 ± 2.55	1.56 ± 2.45	1.11 ± 1.76	0.67 ± 1.18	0.22 ± 0.67
P value (ANOVA test)	0.68	0.57	0.6	0.67	0.83	0.36

ANOVA = analysis of variance

Table 5

Visual analog scale pain scores of lower posterior region

Lower posterior
	4th h	24th h	2nd day	3rd day	4th day	5th day
Metal	0	0	0	0	0	0
Ceramic	1.4 ± 2.87	0.78 ± 2.33	0.67 ± 2.00	0.56 ± 1.00	0.44 ± 1.33	0.34 ± 1.24
P value (ANOVA test)	0.01	0.03	0.03	0.04	0.03	0.03

ANOVA = analysis of variance. P<0.05 statistical significance

Figure 3

Graph for visual analog scale pain scores of upper posterior region (red: ceramic, blue: metal)

Figure 4

Graph for visual analog scale pain scores of lower posterior region (blue: ceramic, red: metal)

DISCUSSION

All the patients included in this study were having Angle’s Class I malocclusion with crowding to ensure that the nature of fixed orthodontic treatment was similar for all the patients in both the groups.

The results showed that in both Group A and Group B, the level of pain was higher during the first 2–3 days following appliance activation. Our findings were similar to several other studies, which evaluated pain experienced because of fixed orthodontic treatment.[3571517]

Moreover, the results suggest important information regarding the occurrence of pain with metal or ceramic fixed orthodontic appliances. Patients undergoing treatment with ceramic brackets recorded appreciable greater VAS scores compared to patients with metal brackets. These results indicate that higher friction might affect tooth movement and produce more pain.

Pain is experienced by 77% of patients during their dental appointments.[1622]

The decrease in intensity of the level of pain was noted by Jones and Chan.[18] The initial experience of pain by the patients occurs as a result of ulceration and inflammation happening during early phase of fixed orthodontic treatment and progressive adjustment of the patients to the orthodontic appliances.

Studies on orthodontic patients[161723] reveal that the level of pain intensity significantly and gradually decreases after 72 h of orthodontic force application. Sergl et al.[25] concluded that the reduction in pain level was noted soon after the peak, which was similar to the findings of our study. This decrease continued until the last day of evaluation in both the groups. The above results might be a diminution of perception concerning the proprioceptive stimulus[2425] or because of the reality that the patient no longer alerted their attention on pain.[17]

The pain, which occurs during fixed orthodontic treatment, is mainly associated with the compression of the periodontal ligament (PDL). The study design comprised two groups having metal and ceramic brackets. The research was focused mainly on the bracket–arch wire interface. Lower frictional forces produce a reduced amount of compression of the PDL and blood vessels, leading to variation in the experience of pain between both the groups.

Several studies have reported that ceramic brackets generate greater friction compared to stainless steel brackets.[2627] As discussed earlier, increased friction in ceramic brackets, with the initial arch wire being same in both the groups, would have generated increased pain in Group B because of greater compression of the PDL and blood vessels.[28]

A study conducted by Burstone[29] classified the pain response into an instant and late response after application of an orthodontic force. He explained the instant reaction because of compression and late reaction because of hyperalgesia of the PDL. The hyperalgesia is linked to the release of prostaglandins.

In a study conducted exclusively on orthodontic wires, Jones[24] concluded that majority of the patients felt pain 4 h after arch wire engagement, which would rise at 24 h and then decrease. The results of this study are similar to our results where there was a peak in pain intensity after 1 day and then declined up to 5 days.

The cold pressor test can be useful in predicting the risk of developing unbearable pain in patients after arch wire placement.[30] As literature review suggests, the main methods of orthodontic pain management are drug administration and the application of low-level laser therapy.[313233343536] A study conducted by Boleta-Ceranto et al.[37] stated that acupuncture is a safe and effective method in reducing orthodontic post-adjustment pain.

Several authors have studied different arch wires to establish differences in pain perception. The intensity, frequency, or extent of pain was same between different arch wires.[162429] This leads us to the conclusion that as the arch wire was also standardized in both the groups, the variation in pain might be due to the brackets only. Previous literature suggests that ceramic brackets generate greater friction as compared because of friction as compared to metal brackets.

A study by Almasoud[38] reported that during the 1st week of orthodontic treatment, patients treated with Invisalign aligners reported lower pain than those treated with passive self-ligating fixed appliances. No difference in the pain perception was observed between the extraction and non-extraction patients during the 7 days after arch wire placement as concluded by Sayar.[39] Meloxicam can be used as an effective analgesic in orthodontic pain control as it has less gastric side effects compared to the conventional nonsteroidal anti-inflammatory drugs.[40]

The strength of our study is that though literature review suggests many studies carried out to evaluate pain perception between various arch wire combinations, bracket combinations, and debonding pain, no study till date has compared the most commonly used brackets in clinical practice, that is, metal and ceramic for their difference in pain perceptions.[4142]

Future research can be carried in more number of samples for a longer duration. Second, future scope is available for evaluating pain perception between labial and lingual brackets and aligners and fixed orthodontic appliance.

The controversial finding in this study is that though the demand of the ceramic brackets is more as they are tooth colored, the pain involved when they are bonded is higher than the conventional metal brackets, which are inferior in aesthetics.

The study definitely provides valuable information when patient care is concerned as in this study, we conclude that though aesthetically superior, ceramic brackets generate higher pain because of higher frictional forces being involved.

CONCLUSION

Patients treated with ceramic brackets experienced elevated and more severe pain and for increased time compared with conventional metal brackets.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.