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Non‐pharmacological interventions for alleviating pain during orthodontic treatment

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Abstract

This is a protocol for a Cochrane Review (Intervention). The objectives are as follows:

The aim of this review is to assess the effects of non‐pharmacological interventions to alleviate pain associated with orthodontic treatment.

Background

Description of the condition

Orthodontics is a specialty within dentistry concerned with the treatment of improper bites, which can be a result of crooked teeth, disproportionate jaws or a combination of the two. The ultimate goal of orthodontics is to create balanced faces with aligned teeth and a good bite that will result in better aesthetics and function. Tooth movement is possible through the application of light forces in patients of all ages. A wide variety of orthodontic appliances, fixed or removable, can be used for this purpose. Removable appliances are loose appliances that can be removed if desired, while fixed appliances are attached to teeth with special glue and cannot be removed by the patient for the duration of the treatment. Furthermore, adjunct appliances such as orthodontic implants have been recently popularised to facilitate therapy.

Imbalances in facial proportions may result from one or both jaws being too small or too large. Growth of such a jaw can be guided with a treatment known as growth modification during which specific types of appliances, known as functional appliances or headgear, are used. Growth modification is only possible in growing patients and is most effective during periods of accelerated growth, commonly known as growth spurts.   

Pain, per definition, is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage (Bonica 1979). The forces needed for tooth movement and growth modification are often associated with discomfort or pain. This can be explained by the fact that tooth movement is only possible through a process of inflammation. During inflammation various biochemical mediators are released and these mediators are responsible for the sensation of pain. Pain during orthodontic treatment is dependent on age (Bergius 2000; Brown 1991; Jones 1985), gender (Bergius 2000; Ngan 1989), psychological well‐being (Bergius 2000; Sergl 1998), culture (Bergius 2000), and previous pain experiences (Bergius 2000; Firestone 1999; Ngan 1989). This makes pain subjective and explains why different patients experience pain differently.

Pain as a result of tooth movement is a common clinical symptom for orthodontic patients. It has been reported that between 70% and 94% of orthodontic patients experience pain during treatment (Firestone 1999; Kvam 1987; Oliver 1985; Schreurer 1996) and that fixed appliances cause more pain than removable appliances (Sergl 1998; Stewart 1997). With fixed appliances, orthodontic pain gradually increases from 2 hours after the placement of the first arch wire (Jones 1984; Schreurer 1996; Soltis 1971), peaks at 24 hours and then decreases gradually, but may last from 2 days to a week (Burstone 1962; Ngan 1989). Orthodontic pain may range from slight discomfort during chewing to a constant, throbbing pain. Unfortunately, no particular arch wire or arch wire sequence was found to cause less pain (Wang 2010).

Description of the intervention

Management of orthodontic pain includes pharmacological and non‐pharmacological interventions. Various drugs are effective for the management of pain during orthodontic treatment (Ngan 1994; Paganelli 1993; Simmons 1992) with non‐steroidal anti‐inflammatory drugs (NSAIDs) being the most commonly used. However, pharmacological or drug interventions may have some negative side effects and some patients may even be allergic to them. For these reasons the non‐pharmacological interventions have also been investigated in the past. Such interventions include the use of bite wafers and chewing gum, low level laser therapy (LLLT), vibratory stimulation, transcutaneous electrical nerve stimulation (TENS), application of ice/cryotherapy, acupuncture/acupressure, and psychological intervention in the form of a structured telephone call to the patients during treatment.

How the intervention might work

LLLT is defined as laser treatment in which the energy produced by the laser is low enough not to cause an increase in temperature and actually stimulates the biological processes within the tissue being treated. It produces a pure light with a single wavelength. It has anti‐inflammatory effects and can repair nerves, which can result in pain relief (Artés‐Ribas 2012; Hashmi 2010).

TENS is a form of stimulation‐produced analgesia. Here two electrical conductors (electrodes) are placed in direct contact with the painful teeth. An electrical current is produced between the two electrodes, which causes the release of natural products and disturbs the nerve responsible for the sensation of pain (Atamaz 2012).

The roots of teeth are surrounded by small fibres called the periodontal ligament (PDL) fibres. These fibres connect teeth to jaws. The theory behind the use of bite wafers (Murdock 2010) and chewing gum (Benson 2012) is that chewing on a bite wafer (or chewing gum) results in loosening of the PDL fibres, and an increase in blood flow to the areas surrounding the roots. This increase in blood flow will prevent or relieve inflammation, which in turn will relieve pain (Furstman 1972).

Cryotherapy is the use of low temperatures for medical treatment, which also modulates pain transmission from tissues. It enhances capillary contraction and reduces the temperature of damaged areas in patients following trauma and/or surgery. Thus, it controls oedema by reducing permeability, haemorrhage and metabolism (Movahedi 2006; Shin 2009).

Acupuncture is a form of alternative medicine methodology. It is believed that the manipulation of thin, solid needles inserted into so called 'acupuncture points' in the skin can relieve certain types of pain. Acupressure is an alternative medicine technique derived from acupuncture. Physical pressure, by hand, elbow, or with the aid of various devices is applied to 'acupuncture points' on the surface of the body. Although they are both used throughout the world to manage acute and chronic pain, their 'modi operandi' and efficacy remain unclear (Cruccu 2007; Paley 2011; Vachiramon 2005).

Another non‐pharmacological intervention mentioned in the literature is the use of a structured telephone call. Some theories imply that psychological factors contribute to the perception of pain (Melzack 1965) and the literature show a relationship between anxiety and pain (Litt 1996; Schupp 2005; Sergl 1998; Theunissen 2012). A structured telephone call can be used to reassure and encourage patients in order to reduce anxiety and ultimately lead to pain relief.

Why it is important to do this review

Pain, in general, motivates us to withdraw from potentially damaging situations or to protect a damaged body part while it heals, and to avoid those situations in the future. This explains why pain during orthodontic treatment has been shown to be the most common reason for patients to discontinue treatment (Kluemper 2002; Oliver 1985; Patel 1989), and why pain is a significant factor affecting patient compliance during treatment (Brown 1991; Patel 1989; Sergl 1998). Orthodontic pain is even a reason for reduced levels of oral hygiene in some patients (Soltis 1971; White 1984). To ensure patient comfort and compliance during treatment, the prevention and management of pain should be of major importance.  

We will investigate the non‐pharmacological interventions for alleviating pain during orthodontic treatment. Pain relief following tooth extraction or surgical procedures associated with orthodontic treatment will not be included. The efficacy of drugs for pain relief during orthodontic treatment is currently being assessed by another Cochrane review (Cooper 2003).

Objectives

The aim of this review is to assess the effects of non‐pharmacological interventions to alleviate pain associated with orthodontic treatment.

Methods

Criteria for considering studies for this review

Types of studies

All randomised controlled trials (RCTs) in which a non‐pharmacological pain intervention is compared concurrently to a placebo/no intervention or another non‐pharmacological pain intervention will be included. If an RCT compares pharmacological and non‐pharmacological interventions to a placebo/no intervention, the study will be included but only the data for a non‐pharmacological intervention will be used.

Types of participants

The criteria for recruiting participants are as follows.

  • Patients with any type of orthodontic treatment.

  • All age groups will be considered.

  • Trials assessing pain relief following orthognathic surgery and/or dental extractions in combination with orthodontic treatment will be excluded.

Types of interventions

The following active interventions to alleviate pain will be assessed.

  • Low level laser therapy (LLLT).

  • Transcutaneous electric nerve stimulation (TENS).

  • Vibrating systems.

  • The use of bite wafers.

  • The use of chewing gum.

  • The application of ice/cryotherapy.

  • Acupuncture/acupressure.

  • Psychological intervention, which includes verbal follow‐up and re‐assurance in the form of a structured telephone call.

Any combination of these interventions at any time during treatment will be evaluated.

Only studies in which interventions were given once moderate or severe pain developed will be included. Studies with patients receiving pre‐emptive intervention(s) will be excluded.

Control

Interventions may be compared to each other, to a placebo, or to the same intervention but at a different dose/intensity or different time interval.

Types of outcome measures

Primary outcomes

  • Patient‐reported pain intensity or pain relief measured on a visual analogue scale (VAS), numerical rating scale (NRS) or any categorical scale.

Secondary outcomes

  • Dose/intensity and frequency of pain relief needed.

  • Any rescue (alternative pain relief taken/prescribed, including dose and time, following the last treatment).

  • Adverse effects of pain treatment.

  • Quality of life and/or patient satisfaction.

  • Time off school/work.

  • Response to treatment (defined as reduction in pain by at least 50%).

Search methods for identification of studies

Electronic searches

For the identification of studies included or considered for this review, a detailed search strategy will be developed for each database searched.

For the MEDLINE search, the subject search will be run with the Cochrane Highly Sensitive Search Strategy (CHSSS) for identifying randomised trials in MEDLINE: sensitivity‐maximizing version (2008 revision) as referenced in Chapter 6.4.11.1 and detailed in box 6.4.a. of the Cochrane Handbook for Systematic Reviews of Interventions version 5.1.0 (updated March 2011) (Higgins 2011).

The following databases will be searched:

  • Cochrane Oral Health Group's Trials Register

  • Cochrane Pain, Palliative and Supportive Care Group's Trials Register

  • Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library current issue)

  • MEDLINE (from 1966 to present) (Appendix 1)

  • EMBASE (from 1980 to present).

Searching other resources

Handsearching

A check will be made to see which journals have already been handsearched as part of the Cochrane Journal Handsearching Programme. The handsearching of the following journals will then be updated to the most current issue as appropriate:

  • American Journal of Orthodontics and Dentofacial Orthopedics;

  • The Angle Orthodontist;

  • European Journal of Orthodontics;

  • Journal of Orthodontics;

  • Australian Orthodontic Journal;

  • Seminars in Orthodontics;

  • Orthodontics and Craniofacial Research;

  • Journal of Orofacial Orthopedics.

If it appears, from searching the Cochrane Pain, Palliative and Supportive Care Group Trials Register, that relevant studies are being found in non‐orthodontic journals, these will also be handsearched. The bibliographies of the clinical trials identified will be checked for references to trials published outside the handsearched journals. Personal references will be checked. Also, other resources such as The British Library EThOS service (http://ethos.bl.uk) will be searched for relevant theses and ClinicalTrials.gov will be searched for otherwise unpublished and ongoing studies.

Language

Databases will be searched to include papers and abstracts published in all languages and every effort will be made to translate non‐English papers.

Unpublished studies

The first named authors of all trial reports will be contacted in an attempt to identify unpublished studies and to obtain any further information about the trials.

Data collection and analysis

Management of records produced by the searches

All references will be downloaded into the EndNote reference management software and merged to produce a single database to facilitate retrieval of relevant articles. Non‐electronic references, that cannot be downloaded, will be entered into the database manually after which duplicates will be removed.

Selection of studies

Two review authors (Hardus Strydom (HS) and Piotr Fudalej (PF)) will independently assess the titles and abstracts (when available) of all potential relevant studies identified by the search strategy. For studies with insufficient information in the title and abstract to make a clear decision to exclude, or studies where there is disagreement between the review authors about eligibility, a full report will be obtained. These full reports will then be assessed independently by the two review authors (HS and PF) to establish whether or not the studies meet the inclusion criteria. Disagreements will be resolved by discussion between HS and PF or the involvement of a third review author (Christos Katsaros (CK)). A record of all decisions made about the potentially eligible studies will be kept. Full reports will also be obtained for those studies that will definitely be included in this review. The review authors will not be blinded to trial author(s), institution or site of publication.

Data extraction and management

Data will be extracted independently by the two review authors (HS and PF), using a pre‐designed data collection form, and saved electronically. The data collection form will be pilot tested for clarity, relevance and completeness. The instruction for coding and meanings will be placed adjacent or near to the data field that is to be coded. The coding of the form with a revision date or version number will be applied to ensure ease of update. Any unpublished information, if used, will be written and coded with a specified remark. The comparison of extracted data will be done by each author independently. Any disagreement will be discussed with a third review author (CK), and the final decisions documented.

The following data will be extracted.

i. Trial methods/characteristics.

  • Study design (RCT).

  • Published/unpublished.

  • Conducted in (country).

  • Number of centres involved.

  • Recruitment period.

  • Duration of the trial (including duration of follow‐up).

  • Funding source.

  • Inclusion criteria.

  • Exclusion criteria.

  • Sample size.

    • Was the sample size calculation described.

    • Number of patients randomised.

    • Number of patients at the start of the trial.

    • Number of patients evaluated.

ii. Intervention.

  • Type of intervention (active and control).

  • Mode of intervention administration (active and control).

  • Duration of intervention (active and control).

  • Dose/intensity of intervention (active and control).

  • Frequency of intervention (active or control).

iii. Primary outcome(s) measured.

  • Outcome(s) measured.

  • Method used to measure the outcome.

  • Mean scores (active and control).

  • Standard deviation (active and control).

  • Time(s) these were measured.

iv. Secondary outcome(s) measured.

  • Secondary outcome(s) measured.

  • Method used to measure the outcome.

  • Mean scores (active and control).

  • Standard deviation (active and control).

  • Time(s) these were measured.

v. Participant characteristics.

  • Age at the start of the trial (mean and range).

  • Culture/ethnicity.

  • Gender.

  • Psychosocial well‐being.

  • Previous pain experience.

Assessment of risk of bias in included studies

The two review authors (HS and PF) will independently evaluate the risk of bias for the included studies, using the following domains (as described in the Cochrane Handbook for Systematic Reviews of Interventions version 5.1.0 (Higgins 2011)): random sequence generation (selection bias); allocation concealment (selection bias); blinding of participants and personnel (performance bias), and outcome assessors (detection bias); incomplete outcome data (attrition bias); selective outcome reporting (reporting bias) and other potential sources of bias. The review authors will follow the Cochrane Collaboration's tool for assessing risk of bias in each included study. The first part of the tool involves describing what was reported to have happened in the study and the second part involves assigning a judgment relating to the risk of bias for each entry. The judgment for each entry is categorized as low risk of bias, high risk of bias, or unclear risk of bias.

An assessment of the overall risk of bias will be summarized after considering the relative importance of the different domains.

  • Low risk of bias ‐ low risk of bias for all domains.

  • Unclear risk of bias ‐ unclear risk of bias for one or more domains.

  • High risk of bias ‐ high risk of bias for one or more domains.

Disagreements will be resolved through consensus, or referred to arbitration by the Cochrane Oral Health Group if needed.

Measures of treatment effect

Because patients generally either respond to an analgesic intervention or they do not, and because pain trials generally do not produce results with Gaussian distributions for pain relief measurements, dichotomous outcomes will be preferred. If the dichotomous outcomes are not directly reported in the studies, we will contact the authors and request the data needed to calculate the proportion of patients with at least 50% reduction in pain from baseline. This will be a predefined clinically useful dichotomous outcome.

We will calculate the following.

  • Risk ratios (RR) and the number needed to treat (NNT) with 95% confidence intervals (CI) for dichotomous outcomes.

  • Mean differences (MD) with 95% CI for continuous data if it is impossible to dichotomize outcomes.

  • Standardized mean differences (SMD) with 95% CI for studies that use different numerical scales to measure the same outcome if it is impossible to dichotomize outcomes.

Outcomes in the treatment and control groups will be assessed as follows.

  • Pain intensity will be assessed as RR (or MD, if dichotomization of the outcome is impossible).

  • Dose/intensity and frequency of pain relief needed will be assessed as RR (or MD, if dichotomization of the outcome is impossible).

  • Any rescue (alternative pain relief taken/prescribed, including dose and time, following the last treatment) will be assessed as MD).

  • Adverse effects of the intervention will be assessed as RR.

  • Quality of life and/or patient satisfaction will be assessed as RR (or MD, if dichotomization of the outcome is impossible).

Dealing with missing data

We will contact trial authors for clarifications or missing information. Where data are unavailable, this will be resolved by estimation on data using the methods described in the section for calculating missing standard deviations of the Cochrane Handbook for Systematic Reviews of Interventions, version 5.1.0 (Higgins 2011). Imputations will be restricted to standard deviations. We will state the assumptions of any methods used to cope with missing data and discuss the potential impact it might have on the findings of the review. An intention‐to‐treat analysis will be conducted wherever it is possible.

In case of the use of 'rescue medication', we will use two imputation methods to calculate estimate of pain relief.

  • Baseline observation carried forward (BOCF) ‐ the pain relief score is set to zero for all remaining time points from rescue medication until the end of the observation period.

  • Last observation carried forward (LOCF) ‐ the last pain relief measurement, at the observation immediately preceding re‐medication, is used for all remaining assessments.

The most appropriate estimate of pain relief would be between BOCF and LOCF.

Assessment of heterogeneity

We will assess heterogeneity using the I2 statistic, where I2 values will be interpreted as follows (Higgins 2011):

  • 0% to 40%: might not be important;

  • 30% to 60%: may represent moderate heterogeneity;

  • 50% to 90%: may represent substantial heterogeneity;

  • 75% to 100%: considerable heterogeneity.

Assessment of reporting biases

We will address publication bias calculating how much data (trials, participants) would be required both to be unpublished and to have zero treatment effect (relative risk/benefit of 1) to make any result clinically irrelevant. In performing this assessment we will follow the guidelines of the Cochrane Pain, Palliative and Supportive Care Review Group (Cochrane PaPaS 2011).

Data synthesis

Meta‐analysis will only be conducted if there are studies of similar comparisons reporting the same outcome measures. Risk ratios will be combined for dichotomous data, and mean differences for continuous data, using the random‐effects model provided there are more than three studies in the meta‐analysis.

The characteristics and results from all included studies will be summarized qualitatively in tabular form.

Subgroup analysis and investigation of heterogeneity

In case of significant heterogeneity, the following subgroup analyses will be conducted to explore its source.

  • Type of interventions.

  • Dose/intensity of interventions.

  • Characteristics of participants: age, gender, ethnicity, psychological well‐being and previous pain experienced.

  • Type of orthodontic appliance used.

Sensitivity analysis

Providing there are sufficient included trials, sensitivity analysis based on risk of bias (low risk of bias versus high or unclear risk of bias) will be done to investigate the robustness of conclusions to decisions made during the review process.

Presentation of main results

A summary of findings (SoF) table will be developed for the primary outcomes of this review using GRADEpro software. 

The quality of the body of evidence will be assessed with reference to.

  • The overall risk of bias of the included studies.

  • The directness of the evidence.

  • The inconsistency of the results.

  • The precision of the estimates.

  • The risk of publication bias.

  • The magnitude of the effect.

  • Whether or not there is evidence of a dose response. 

The quality of the body of evidence for each of the primary outcomes will be categorized as:

  • High

  • Moderate

  • Low

  • Very low.