A randomized controlled trial to assess the pain associated with the debond of orthodontic fixed appliances.

0.75 MB·English

by  Mangnall, Louise A R

OPENACCESS JournalofOrthodontics,Vol.40,2013,188–196
A randomized controlled trial to assess
SCIENTIFIC
SECTION
the pain associated with the debond of
orthodontic fixed appliances
Louise A. R. Mangnall1, Thomas Dietrich2 and John M. Scholey3
1DepartmentofOrthodontics,Mid-StaffordshireNHSFoundationTrust,Stafford,UK;2DepartmentofOral
Surgery,SchoolofDentistry,UniversityofBirmingham,Birmingham,UK;3DepartmentofOrthodontics,
UniversityHospitalofNorthStaffordshire,Stoke-on-Trent,UK
Objective: Todeterminepatientexperienceofpainduringtreatmentwithfixedorthodonticappliances,expectationsofpain
duringdebond andwhether biting ona softacrylic waferduring debonddecreases painexperience.
Design:Multicentre randomizedcontrolledtrial.
Setting:ThreeUKhospitalbasedorthodonticdepartments:Mid-StaffordshireNHSFoundationTrust,BirminghamDental
Hospital andUniversity Hospitalof NorthStaffordshire.
Materialsandmethods:Ninetypatientswererandomlyallocatedtoeitherthecontrol(n545)orwafergroup(n545).Avisual
analogue scale-based questionnaire was completed pre-debond to determine pain experience during treatment and
expectations of pain during debond. The appliances were debonded and those in the wafer group bit on a soft acrylic
wafer. A secondquestionnaire was completedpost-debond to assessthe painexperienced.
Results:Bitingonanacrylicwafersignificantly reducedthe painexperiencedwhendebondingthe posteriorteeth (P#0.05).
Thirty-nine per cent found the lower anterior teeth the most painful. The expected pain was significantly greater than that
actuallyexperienced(P#0.0001).Greaterpainduringtreatmentcorrelatedwithincreasedexpectationsandincreasedactually
experiencedpain(P#0.0001).
Conclusions: Biting on a soft acrylic wafer during debond of the posterior teeth reduces the pain experienced. The lower
anterior teeth are the most painful. The pain expected is significantly greater than actually experienced. Patients who had
greater painduringtreatment expected andexperiencedgreater painat debond.
Keywords: Pain, debond,fixed appliances
Received 1October2012;accepted 13January2013
Introduction depolarisation of local pain nerve fibres. Orthodontic
forcescreate zones of pressureand tension in the period-
Pain is defined by the International Association for the ontalligamentspace,resultinginaninflammatoryreaction
Study of Pain (1994) as an ‘unpleasant sensory and withintheperiodontiumandpulpalongwiththereleaseof
emotionalexperienceassociatedwithactualorpotential inflammatorymediators.Itisthoughtthattheperception
tissue damage’. It is a subjective experience, with great of pain is influenced by changes in blood flow and is
individual variation and is dependent upon various correlated with the release of mediators such as prosta-
factorssuchasage,gender,emotionalstate,cultureand glandins,leukotrienes,histamine,serotoninandsubstance
previous pain experience. Pain or discomfort is experi- P, which elicit a hyperalgesic response. The increase of
enced by up to 95% of patients during orthodontic these mediators following the application of force is well
treatmentandhasbeencitedasareasonfordiscontinu- documented in the dental and orthodontic literature.3,4
ing treatment.1,2 Burstone5 described an immediate and a delayed pain
Pain is caused by tissue damage that results in cell response to orthodontic forces. The immediate response
death and subsequent release of intracellular factors was due to compression of the periodontal ligament and
suchashistamine,substanceP,bradykinin,prostaglandins the delayed response due to hyperalgesia of the period-
and serotonin that stimulate nociceptors and cause ontalligament.
Addressforcorrespondence:L.Mangnall,Departmentof
Orthodontics,Mid-StaffordshireNHSFoundationTrust,Stafford,UK
Email:[email protected]
#2013BritishOrthodonticSociety
MOREOpenChoicearticlesareopenaccessanddistributedunderthe
termsoftheCreativeCommonsAttributionNon-CommercialLicense3.0 DOI10.1179/1465313313Y.0000000045
JOSeptember2013 ScientificSection Painassociatedwithdebondingfixedappliances 189
As part of the informed consent process, patients scale(VAS)(100 mmlong)withastandarddeviationof
should be advised of all of the risks and benefits of 20 mm, a significance level of 0.05 and a power of 80%.
treatment including the potential for pain at all stages. Thisgavearequiredsamplesizeof39subjectspergroup
Previous research has investigated levels of pain with a total of 78 subjects. A 13 mm reduction in pain
experienced during and after various procedures, such scorewasdeemedtobeclinicallysignificantbyresearch
as the placement of separators,6,7 activation of arch- previously carried out in accident and emergency
wires8–10 and the use of different bracket systems,11–14 departments on children aged 5–16 years in acute
along with methods of pain reduction. However, pain pain.16 To date, there have been no studies determining
experienced during the debond of fixed appliances is clinically significant reduction in pain scores for
currently poorly quantified in the published literature. orthodontic patients.
Further investigation is therefore required, not only for All eligible patients were given verbal and written
consent, but to enable review of potential methods for information describing the trial and the opportunity to
minimizing discomfort. ask further questions. Inclusion criteria for the study
Williams and Bishara15 conducted a pilot study of 15 were:
subjects to investigate the level and direction of force N
informed consent gained from patients and parents;
thatcouldbetoleratedatdebond.Torsionalforceswere N
patients aged 12–18 years;
very poorly tolerated and less than 100 g of force could N
patientswithfullorthodonticfixedappliancesinboth
be applied before discomfort was experienced, while
arches with either Victory or SmartClip brackets
intrusional forces were relatively well tolerated, with a
(both 3M Unitek) precoated with APC adhesive.
discomfort threshold of 934 g. Mobility of the teeth
reduced the discomfort threshold. The periodontal Exclusion criteria included:
structures are designed to withstand intrusive forces N
patients who had completed a previous course of
during mastication and it is logical that intrusive forces
orthodontic treatment;
would be best tolerated. They suggested that stabilizing N
patientswhowereunabletocomprehendorcomplete
the teeth by asking the patient to bite on a cotton
the questionnaire;
wool roll during debond may reduce the discomfort N patients with craniofacial syndromes.
experienced.
RandomizationwascarriedoutusingMinitabcomputer
This study aims to determine: (1) pain experience
software.Sealedopaqueenvelopes wereusedtoconceal
during orthodontic fixed appliance treatment; (2)
theallocationandtheywereopenedindependentlyupon
expectationsofpainduringthedebondingoforthodon-
patientrecruitment.Informedconsentwasobtainedand
tic fixed appliances; and (3) whether biting on a soft
the patients were randomly allocated to one of two
acrylic wafer reduces pain experience during the
groups, the control group (group 1) or the wafer group
debonding of orthodontic fixed appliances.
(group 2). Both groups completed the first VAS-based
The primary null hypothesis was that biting on a soft
questionnaire investigating their overall pain experience
acrylic wafer during debonding of fixed appliances does
during fixed appliance treatment, their anxiety levels
not reduce pain experienced and the secondary null
beforethedebondandtheirexpectationsofpainduring
hypothesis was that there is no difference between
theremovaloftheirappliances.TheVASconsistedofa
expected and perceived levels of pain during the
100 mm line labelled at the extremes with ‘no pain’ and
debonding of fixed appliances.
ahappyfaceand‘worstpainimaginable’andasadface.
The investigator was present while the questionnaires
Materialsandmethods were answered to supervise and provide further infor-
mation, if required.
This prospective randomized controlled trial recruited Following completion of the first questionnaire the
patients from the orthodontic departments of the Mid- fixed appliances were debonded using a standardized
StaffordshireNHSFoundationTrust,BirminghamDental procedure. Debonding pliers, with right-angled beaks,
HospitalandUniversityHospitalofNorthStaffordshire. wereused,beginningwiththeupperrightquadrantand
Ethical approval was gained from the Northern and workingaroundtotheupperleftquadrant,followedby
Yorkshire Research Ethics Committee, reference num- the lower right quadrant around to the lower left
ber: 09/H0903/6. Local NHS Research and Develop- quadrant. The archwire was left in-situ during the
ment approval was gained for the three sites. debond. Those in the wafer group bit into a soft acrylic
The sample size calculation was based on a clinically wafer as their appliances were debonded (Figure 1)
significant difference of 13 mm on a visual analogue and the control group stayed open with their teeth
190 Mangnalletal. ScientificSection JOSeptember2013
Figure 1 The soft acrylic bite wafer and the wafer in use during the debond
out of occlusion. On completion of the debond, the The intra-examiner reliability for the measurement of
patients completed the second questionnaire to deter- the VAS was performed using intra-class correlation
minetheactualamountofpainexperiencedduringthe following re-measurement of 15 subject questionnaires.
debond. Theintra-classcorrelationcoefficientwas0.984,indicat-
The soft acrylic bite wafers were manufactured by the ing good intra-examiner reliability for the measurement
orthodonticlaboratoryatBirminghamDentalHospital. of the VAS.
Theywereconstructedfrom3 mmtransparentDrufosoft
material(DreveGmbH)(Figure 1).
Results
The questionnaires were analysed by one operator
who was blinded to the group allocation. Digital
Aconsortdiagramshowingtheflowofpatientsthrough
callipers were used to measure the visual analogue scale the study is shown in Figure 2.
scores and intra-examiner reliability for the measure-
ments was tested by re-measuring 15 questionnaires
Baseline data
1 month later.
Ninety patients participated with 45 in each group.
Statistical analysis Therewere 51females and 39 maleswitha meanage of
16 years (SD: 1.5 years). The control group comprised
The Predictive Analytics SoftWare (PASW 18.0) statis- 23 females and 22 males with a mean age of 15.9 years
tical program was used for the statistical analysis of (SD: 1.5 years), while the wafer group had 28 females
data. The results were not normally distributed so a and 17 males with a mean age of 16 years (SD:
logarithmic transformation was applied to all the VAS 1.6 years).
pain scores, before carrying out the analyses to enable Thedurationoffixedappliancetreatmentrangedfrom
the use of parametric statistical tests. 12–48 months withameanof26.9 months.Satisfaction
The effect of the intervention (control or wafer withtheoveralltreatmentresultwasgenerallyhighwith
group) was assessed using multiple linear regression a median VAS score of 98.3 (Table 1).
analysis and the model was adjusted for age, gender,
type of molar attachment and the expected pain at
Expectations of pain during the debond process
debond. To facilitate interpretation of the multiple
linear regression b coefficients, based on a log- The expectations of pain during debond are shown in
transformed outcome, they are reported as the percen- Table 1. Both groups had a similar level of anxiety
tage difference in pain, calculated using the formula: aboutthedebondandsimilarexpectationsofpain,with
[exp (b)21]6100%. a full range of scores given (0–100).
The difference between the expected and actual pain
scores was determined using Wilcoxon signed-rank
Pain experienced during fixed appliance treatment
analysis. Spearman’s Rank correlations were deter-
mined between the overall pain experienced during the Figure 3 shows the pain experienced overall during the
fixed appliance treatment,the level of anxiety about the fixed appliance treatment along with the pain during
debond, the overall pain expected during the debond adjustment of the appliances and the pain 24 h after
and the actual pain experienced at debond. Descriptive adjustment. Patients reported that the pain 24 h after
statistics were used to determine the most painful adjustment of their appliances was greater than that
sextant during the debond. overall or during the actual adjustment.
JOSeptember2013 ScientificSection Painassociatedwithdebondingfixedappliances 191
Figure 2 Consort flow diagram
Table 1 Baselinedata:patientdemographicsandtheVASscoresfortheexpectationsofpainduringthedebond.
Group1—control Group2—wafer Total
Subjects Number 45 45 90
Males(%) 22(48.9) 17(37.8) 39(43.3)
Females(%) 23(51.1) 28(62.2) 51(56.7)
Age(years) Mean(SD) 15.9(1.5) 16.0(1.6) 16.0(1.5)
Treatmentduration(months) Mean(SD) 26.1(7.3) 27.7(9.8) 26.9(8.6)
Range 12–41 12–48 12–48
Satisfactionwithtreatmentresult Mean(SD) 91.6(14.0) 94.8(8.8) 93.2(11.7)
Median 98.5 98.2 98.3
Range 48.8–100 49.2–100 48.8–100
Expectationsofpain
Anxietyaboutdebond Median 13.2 11.4 11.4
Range 0–89.9 0–100 0–100
Painoverall Median 25.9 33.6 33.1
Range 0–76.0 0–99.4 0–99.4
Upperposteriorteeth Median 29.4 30.4 30.2
Range 0–88.1 0–100 0–100
Upperanteriorteeth Median 33.2 34.8 33.7
Range 0–85.7 0–87.7 0–87.7
Lowerposteriorteeth Median 22.3 23.6 23.0
Range 0–83.8 0–89.6 089.6
Loweranteriorteeth Median 26.0 27.9 27.8
Range 0–75.7 0–95.7 0–95.7
Compositeremoval Median 29.6 21.5 23.8
Range 0–92.4 0–88.4 0–92.4
192 Mangnalletal. ScientificSection JOSeptember2013
Figure 3 Box and whisker plot of the pain experienced during fixed appliance treatment
bybothgroups.Debondofthelowerposteriorteethwas
The actual pain experienced at debond
thesecondmost painful,followed bytheupperanterior
The pain experienced at debond is shown in Figure 4. teeth with the upper posterior teeth being the least
Theoverallpainexperiencedandthatexperiencedforall painful.
quadrants,exceptthe lower anterior teeth, was lower in Themedianpainscoreforcompositeremovalwasless
the wafer group than in the control group. Debond of than that of the overall pain experienced during the
theloweranteriorteethwasreportedasthemostpainful debond.Theloweranteriorteethwerechosenasthemost
Figure 4 Box and whisker plot of the pain experienced during debond for the control and wafer group
JOSeptember2013 ScientificSection Painassociatedwithdebondingfixedappliances 193
Figure 5 The most painful sextant during the debond, as reported by the patients
painful sextant by 39%, followed by the upper right Once the multiple linear regression model had been
sextant(18%)(Figure 5). adjusted the wafer group had significantly less pain
Multiple linear regression analysis was used to during debond of the upper posterior teeth (P50.037)
examine the effect of the intervention and the results and the lower posterior teeth (P50.031).
are shown in Table 2. The wafer group had lower pain The expected pain scores were significantly greater
scores overall, for the posterior teeth and the upper than the experienced scores overall, for all quadrants
anterior teeth with up to a 36% reduction in the pain and for the composite removal (P#0.001) (Table 3).
scores, for the lower posterior teeth; however, this did Table 4 shows the correlations between expected and
not reach statistical significance (P50.107). actuallyexperiencedpainscores.Therewerecorrelations
Table 2 Multiplelinearregressionanalysisfortheeffectoftheintervention,adjustedforage,gender,typeofmolarattachmentandtheexpected
levelofpainatdebond.Percentagesareusedtogivemeaningtothelogarithmicallytransformeddata.
Age,gender,molar
Age/gender Age,gender,molar attachment,expected
Control/wafer adjusted attachmentadjusted painadjusted
Overall B 20.31 20.35 20.33 20.44
%differenceinpain 227% 230% 228% 236%
95%confidenceinterval 256%,22% 259%,22% 255%,22% 259%,11%
P-value 0.236 0.183 0.204 0.079
Upperposteriorteeth B 20.4 20.46 20.45 20.58
%differenceinpain 233% 237% 236% 244%
95%confidenceinterval 263%,22% 263%,11% 263%,11% 267%,0%
P-value 0.161 0.107 0.118 0.037
Upperanteriorteeth B 20.22 20.29 20.28 20.45
%differenceinpain 220% 225% 224% 236%
95%confidenceinterval 255%,35% 255%,35% 255%,35% 263%,11%
P-value 0.427 0.292 0.319 0.078
Lowerposteriorteeth B 20.44 20.49 20.47 20.58
%differenceinpain 236% 239% 237% 244%
95%confidenceinterval 263%,11% 263%,11% 263%,101% 267%,210%
P-value 0.107 0.70 0.086 0.031
Loweranteriorteeth B 0.095 0.03 0.03 20.18
%differenceinpain 10% 3% 3% 216%
95%confidenceinterval 239%,101% 239%,82% 245%,82% 250%,35%
P-value 0.742 0.912 0.933 0.496
194 Mangnalletal. ScientificSection JOSeptember2013
Table 3 TheWilcoxonsigned-ranktesttocomparetheexpectedpainscoreswiththeactuallyexperiencedpainscores.ZistheWilcoxonsigned-
ranktestresult.
Upperposterior Upperanterior Lowerposterior Loweranterior
Overallpain teeth teeth teeth teeth Compositeremoval
Z 24.194 24.053 25.349 23.569 24.159 23.274
Significance ,0.0001 ,0.0001 ,0.0001 ,0.0001 ,0.0001 0.001
P-value
between the level of pain experienced during the course experienced more pain. The emotional state of the
of fixed appliance treatment and the anxiety about the patient can modulate pain experience and increased
debond (correlation coefficient r50.215, P50.041), the anxietycanacttolower thepainthreshold.Conversely,
expected level of pain at debond (r50.373, P#0.0001) themotivationtowearappliancesmayservetoincrease
and the pain experienced during the debond (r50.408, the pain threshold or filter out painful stimuli.20,21
P#0.0001). The level of anxiety about the debond Similarly, excitement about the often long-awaited
correlated with the expected pain (r50.617, P#0.0001) debond, may reduce the pain experienced by raising
and with the actually experienced pain (r50.249, the pain threshold or filtering painful stimuli.
P50.018). The expected pain scores correlated with WilliamsandBishara15intheirpilotstudyoftheforce
the actually experienced pain scores (r50.340, that could be tolerated at debond, found the lower
P50.001). incisors had the lowest threshold and that mobility of
the teeth reduced the threshold further. The type of
forceappliedaffectedthethresholdfordiscomfort,with
Discussion
intrusive forces tolerated best and torsional forces very
This study showed that biting on a soft acrylic wafer poorly tolerated. They concluded that providing an
during debond of the posterior teeth significantly intrusive force on the teeth during debond may reduce
reduced the pain experienced (P#0.05). However, there the discomfort experienced. Our study showed that an
was no statistically significant reduction in pain for the intrusive bite force significantly reduced the pain
anteriorteeth.Theloweranteriorteethwerereportedby experienced for the posterior teeth, but was not
39% of subjects to be the most painful sextant during significant for the anterior teeth. This difference may
debond, while the upper right posterior teeth were be due to the ability of the posterior teeth to provide a
reported to be the most painful by 18%. greaterbitingforce,whichisdistributedalongthelong-
Painisverysubjective,withgreatindividualvariation. axis of the tooth. The wafer was repositioned when
In this study, the large ranges of pain scores given both debonding the upper anterior teeth to ensure all teeth
duringtreatmentandduringthedebondmirrorprevious were in contact, but due to the small differences in the
descriptions in the literature.7–10,12,14,17–19 Subjects who level of the incisal edges, the intrusive force may have
experienced more pain during treatment were more been reduced and because of their inclination the
anxious about the debond and both expected and force was not distributed along the long-axis. When
Table 4 Spearman’srankcorrelationsbetweentheoverallpainexperiencedduringthefixedappliancetreatment,thelevelofanxietyaboutthe
debond,theoverallpainexpectedduringthedebondandtheactualpainexperiencedatdebond.
Overallpainduring Anxietyabout Overallpain Overallpain
fixedappliances thedebond expected experienced
Overallpainduring Correlationcoefficientr 1.000
fixedappliances P-value .
Anxietyaboutthedebond Correlationcoefficientr 0.215 1.000
P-value 0.041 .
Overallpainexpected Correlationcoefficientr 0.373 0.617 1.000
P-value ,0.0001 ,.0001 .
Overallpainexperienced Correlationcoefficientr 0.408 0.249 0.340 1.000
P-value ,0.0001 0.018 0.001 .
JOSeptember2013 ScientificSection Painassociatedwithdebondingfixedappliances 195
debonding the lower anterior teeth, the patient bit into the potential discomfort of the actual adjustment
the wafer in an edge-to-edge incisor position. This process.
ensured that there was sufficient space to accommodate
the beaks of the debond pliers between the incisal edge Expectations of the debond process
of the bracket and the upper incisors. It is conceivable
that this forward positioning of the mandible would The median anxiety score of 11.4 suggests a relatively
reduce the biting force. Using a graduated wafer which low level of anxiety overall, but a full range of scores
is thicker anteriorly and made of a slightly softer were given. Forty-six subjects listed specific concerns.
material, may allow an even biting force to be applied The commonest was, ‘having white marks’ or, ‘dis-
to all teeth. Alternatively, biting on a firm cotton wool coloured teeth’ (47.8%), followed by pain (41.3%).
roll,whichissmaller,easiertopositionandmorereadily Decalcification is a risk of orthodontic treatment and
available in most clinical settings, could provide a patients should be informed of this at the start of
similar effective, intrusive, stabilizing force. treatment.The extent ofdecalcification isoften obvious
beforedebondandreassurancecanbegivenpre-debond
which may help to alleviate some of this anxiety.
Strengths and weaknesses of the study
In this study, the use of a bite wafer ensured a
Debonding-fixed appliances
standardized thickness and consistency, instead of
cotton wool rolls which can vary significantly. Theoretically biting on a soft acrylic wafer or a cotton
The use of multiple linear regression analysis enabled wool roll equivalent reduces pain by applying an
various confounding factors to be accounted for intrusive force to the teeth. The intrusion helps to
including gender, type of molar attachment (bonded stabilize the teeth and counteract the sheer/peel and
tubes or bands) and the expectations of pain during the torsional forces applied to the periodontal ligament
debond. Half of the subjects (51.1%) had bonded tubes during the debond. The additional pressure on the
onallfourfirstmolars,16.7%hadbandsonallfourfirst periodontal ligament may also provide a proprioceptive
molars and 32.2% had a combination of bands and stimulus,helpingtoreducethepainexperienced,akinto
tubes. Those with bands on their molars could not the gate theory of pain control whereby rubbing an
occludeasthebandsweredebonded.Thedistributionof injured limb helps to take away pain. Occluding during
males to females was equal in the control group, but debond also helps protect the airway by forcing a loose
there were a greater proportion of females in the wafer bracket towards the buccal sulcus, rather than poten-
group. As females are potentially more likely to report tially down the airway.
pain than males,7,10,20–22 the uneven gender distribution The lower anterior teeth were said to be the most
may have underestimated the effect of biting on the painful by 39% and can be explained by the greater
wafersandstratifyingthegroupsforgenderwouldhave debond force per unit surface area of the root.
avoided this. The upper anterior teeth were expected to Explanation of why the upper right posteriors were
be the most painful during the debond. Potentially, this reportedasthemost painful by18%ismore difficult. It
is because the upper anterior teeth had been felt to be could be because this was the first sextant to be
the most painful during the course of treatment. This debonded and as such, was the most memorable.
might be expected if the upper anterior teeth had been Additionally, the clinicians carrying out the debonds
bodily retracted during treatment. However, neither the were right-handed and using a pair of right-angled
typeofpresentingmalocclusion,extractiondecisionnor debonding pliers. Operating on the right side requires a
the most painful sextant during the fixed appliance more rotated hand position causing a grip which has a
treatment was recorded during the data collection to greaterchanceofapplyingmorepainfultorsionalforces
confirm this. when debonding.
The results of this study suggest that biting on a safe,
Implications for clinical practice: pain during fixed partially compressible material during debond, may
make the process more comfortable and that spending
appliance treatment
time to alleviate anxiety about the expectations of pain
Pain experience during and after the adjustment of during debond is likely to be worthwhile. The null
appliances was variable with a wide range of scores hypothesis that biting on a soft acrylic wafer during
given. It is usual to warn patients about pain following debonddoesnotreducethepainexperiencedistherefore
adjustment; however, we should also be mindful about rejected for posterior teeth and accepted for anteriors.
196 Mangnalletal. ScientificSection JOSeptember2013
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