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ORIGINAL ARTICLE

The prevalence of bruxism has been reported as being between 8% and 25% in the general adult population in different countries worldwide and as even higher among patients with certain clinical di-agnoses, e.g. temporomandibular disorders (Kato et al, 2003; Lavigne et al, 2003; Nekora-Azak et al, 2010). The clinical consequences of bruxism can be quite severe and were already well described in

Occlusal Splints and Quality of Life Does the Patient-Provider Relationship Matter?

Marita R. Ingleharta/Sven-Erik Widmalmb/Paul J. Syriacc

Purpose: Occlusal splints are often prescribed when treating patients with bruxism. The objectives were to determine (a) whether using occlusal splints improves patients oral health-related quality of life (ohrqol) and (b) whether the qual-ity of the patient-provider relationship affects these patients splint-related responses and their ohrqol.

Materials and Methods: Survey data were collected from 233 patients who had received bite splints during the 5 years prior to data collection.

Results: The data showed that 5% of these patients had never used their splint, 20% had used it in the past, and 75% still used it at the time of data collection. Patients using the splint agreed more strongly that their current oral health status had improved, had more positive splint-related responses and more positive pain-related ohrqol scores than patients who were no longer using the splint. The more patients agreed that they were satisfied with their provider, the more positively they evaluated their bite splints and the more positive was their ohrqol.

Conclusions: Bite splint users have more positive splint-related responses and a better pain-related ohrqol than pa-tients who received a bite splint but do not use it any longer. The quality of the patient-provider relationship plays an important role in the patients splint-related responses as well as in the degree to which patients ohrqol improves.

Key words: bruxism, communication, compliance, cooperation, occlusal splint, quality of life

Oral Health Prev Dent 2014;12:249-258 Submitted for publication: 02.09.12; accepted for publication: 02.03.13

doi: 10.3290/j.ohpd.a32131

a Professor, Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan; Adjunct Professor, Depart-ment of Psychology, College of Literature, Science and Arts, Uni-versity of Michigan, Ann Arbor, MI, USA.

b Associate Professor, Department of Biologic and Materials Sci-ences, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.

c Research Assistant, Department of Periodontics and Oral Medi-cine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA.

Correspondence: Dr. Marita R. Inglehart, Department of Periodon-tics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI 48109-1078, USA. Tel: +1-734-763-8073, Fax: +1-734-763-5503. Email: mri@umich.edu

1966 by Ramfjord and Ash (Ramfjord and Ash, 1966). These authors discussed nonfunctional grinding and gnashing vs clenching in centric occlu-sion as two main categories of oral dysfunctional habits, using the labels eccentric and centric brux-ism. They pointed out that most severe bruxism usually occurs at night (Ramfjord and Ash, 1966) and pointed to the possible influence of local fac-tors, such as occlusal interferences and occlusal habits, while later research has emphasised the role of central regulation.

The consequences of bruxism were recently cat-egorized in a review by Klasser et al (2010) as (a) dental consequences such as severe occlusal and incisal wear, tooth fractures, tooth mobility and hy-persensitivity of teeth, (b) temporomandibular prob-lems as well as (c) other consequences, such as reduction of salivary flow or lip/cheek/tongue bit-ing. The causes, consequences and treatment op-tions for bruxism have been widely discussed in the literature since this term was first introduced to the scientific community in 1907 (Pietkiewicz, 1907).

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The American Academy of Sleep Medicine defines bruxism as stereotyped oral motor disorder charac-terized by sleep-related grinding and/or clenching of the teeth (Manfredini et al, 2011), and the Ameri-can Academy of Orofacial Pain provides a definition that describes these behaviours when also dis-played during wakefulness (De Leeuw, 2008).

A wide range of management strategies have been suggested for the treatment of bruxism. They include behavioural interventions such as psycho-logical counseling, hypnosis or biofeedback (Om-merborn et al, 2007), as well as dental and phar-macological interventions such as the use of muscle relaxants or dopamine-related medications (Saletu et al, 2010). One common strategy is the use of oral appliances (Ash and Ramfjord, 1966, 1995; Klasser et al, 2010). Lobbezoo et al (2010) argued that a lack of well-designed scientific stud-ies does not allow making final conclusions con-cerning the effectiveness of behavioural ap-proaches, and Klasser et al (2010) concluded that no definitive pharmacological treatment can be rec-ommended for a long-term treatment. Oral appli-ances thus remain an important treatment option in the management of patients with bruxism. While a recent Cochrane review article could not find suf-ficient evidence that the use of oral appliances re-sulted in improved sleep, the evidence suggested that they may be of benefit for preventing tooth wear (Macedo et al, 2007).

While research has shown that many patients with bruxism experience signs and symptoms of temporomandibular dysfunction, such as pain and restriction in movement, and as a consequence have a significantly impaired quality of life (List et al, 2006), no research so far has explored whether the use of occlusal splints results in an improve-ment of the patients oral health-related quality of life (ohrqol) (Inglehart and Bagramian, 2002; Ingle-hart et al, 2013). Therefore, the first objective is to analyse whether patients using a bite splint have more positive bite splint-related responses and a better ohrqol than patients who received a bite splint but are not using it anymore.

In addition, it is interesting to reflect on which factors might affect whether patients actually use their bite splint and whether these factors might moderate how positively bite-splint use affects pa-tients splint-related responses and their ohrqol. Specifically, it is of interest whether the patients relationships with their providers affect their bite-splint use and the psychosocial outcomes of this treatment. Research provides quite convincing evi-

dence for the fact that the quality of patient-provid-er communication is crucial for treatment coopera-tion and treatment outcomes. For example, when Patel et al (2006) explored which patients would follow their periodontists recommendation to have periodontal surgery, they found that patients who decided to have the surgery did not differ from the patients who decided against surgery in their per-ceptions concerning how well their dentists had in-formed them about the procedure. However, these two groups of patients differed significantly in their perceptions of the emotional quality of their interac-tions with their dentists. Other studies have pro-vided additional support for the importance of good patient-provider communication for patients satis-faction with their provider (Sondell et al, 2002; Shouten et al, 2003; Okullo et al, 2004; Kim et al, 2012), for reducing patients dental fear and anxi-ety (Corah et al, 1985; Hottel and Hardigan, 2005), for increasing their confidence in their dentist (Co-rah et al, 1988; van der Molden et al, 2004) and for achieving more positive treatment outcomes (Carey et al, 2010). Hence, the second objective was to explore whether the quality of the patient-provider relationship affects bite-splint-related responses. Specifically, it was investigated whether the infor-mational (Did the provider explain the use of the bite splint well?) vs the emotional aspects (How satisfied are you with your provider?) of patient-provider relationships play a role in this context.

MATERIALS AND METHODS

This study was approved by the Institutional Review Board for the Behavioral and Health Sciences at the University of Michigan, in Ann Arbor, MI.

Respondents

An a priori power analysis with the program package G*Power 3.1.2 (http://www.psycho.uni-duessel-dorf.de/abteilungen/aap/gpower3) was conducted to compute the needed sample size given al-pha = 0.05, power = 0.80 and a medium effect size of 0.5 for testing with a t-test whether the means of two independent samples (subjects who used vs did not use a provided bite splint) were significantly different in such a way that the users would have more positive responses than the non-users. It was assumed that the proportion of users vs non-users would differ in a relationship of 3:1. This analysis

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showed that a minimum of 51 subjects in each of the two groups would be required in order to attain the power to test the hypothesis that the two inde-pendent groups differed as predicted.

Surveys were mailed to 496 patients who had received a Michigan occlusal splint (Ash and Ramf-jord, 1995) for the maxilla during the past five years prior to the study at the University of Michigans School of Dentistry clinic in Ann Arbor, MI, USA. It should be noted that occlusal splint was the term preferred by Ash and Ramfjord in their later publica-tions (Ramfjord and Ash, 1995). However, the term bite-splint seems to still be more commonly known and will therefore be used here as a synonym. All splints were made by dental students who were su-pervised by licensed clinical faculty members. Six-ty-seven of the surveys (11.9%) were undeliverable and were returned to the research team. Respons-es were received from 233 former patients (re-sponse rate: 54.3%). Fifty-seven patients did not use the bite splint (25%) at the time of the survey and 172 (75%) still used the bite splint.

Procedure

The investigators were not allowed to have direct access to the patient records because of privacy concerns. However, they were able to prepare the mailing by providing envelopes with a cover letter that explained the study, the survey and a stamped self-addressed return envelope. The Office of Pa-tient Affairs at the dental school searched for all patients who had received bite splints during the 5 years prior to the study and affixed their addresses to the envelopes and then mailed the envelopes to these patients. The recipients returned the surveys anonymously.

Materials

The survey asked the patients questions about their age and gender, explored their bite splint use history and their responses to the bite splint and assessed the patients oral health-related quality of life (ohrqol) and their relationship with their providers.

The patients ohrqol was assessed with a stand-ardised scale, the Michigan Oral Health-related Quality of Life Scale Adult Version (MOHRQoL-A; Inglehart et al, 2013, submitted). The 14 MOHRQoL items are Likert-type items with a 5-point answer scale from 1 = disagree strongly to 5 = agree

strongly. A factor analysis (extraction method: prin-cipal component analysis; rotation method: Vari-max with Kaiser normalisation) of the 14 MOHRQoL items showed that responses loaded on two fac-tors, namely one factor assessing the patients pain experiences (Cronbach alpha = 0.88) and a second factor assessing their psychological well-being (Cronbach alpha = 0.83).

Statistical analysis

The data were analysed with SPSS (Version 19). Descriptive statistics (e.g. means, ranges) were used to provide an overview of the responses. Group comparisons of the average responses of persons who used vs did not use the bite splint and of patients with different levels of satisfaction with their providers were analysed with multivariate analyses of variance (MANOVAs). A value of p 0.05 was assumed as the significance level.

RESULTS

The MOHRQoL Adult Version was found to have ex-cellent reliability (Cronbach alpha = 0.96) and valid-ity (Inglehart et al, 2013, submitted). The internal validity was assessed by correlating the responses to the MOHRQoL with the responses to the OHIP-14 (r = 0.77; p < 0.001). The external validity was determined by correlating the total MOHRQoL scores of 705 adult patients with their objectively assessed oral health indicators such as the num-ber of missing teeth (r = 0.43; p < 0.001) and the number of surfaces with untreated caries (r = 0.26; p < 0.001) (Inglehart et al, 2013, submitted).

An analysis of the patients background charac-teristics showed that two-thirds of the respondents were female. The average age was 42.89 years (range: 2087 years; standard deviation = 15.604). Concerning bite-splint use, Table 1 shows that nearly half of the respondents had received their splints between 1 and 2 years ago (45%), 30% had received it between 2 and 3 years ago, and only 18% between 3 and 5 years ago. Reasons for re-ceiving the bite splint were teeth grinding (78%), teeth clenching (51%), as well as pain in the jaw (34%) and headaches (20%). When asked if they had used their bite splint, 11 respondents (5%) in-dicated that they had never used it. The reasons for not using the splint were technical (N = 10; examples: was not made properly; never fit) or

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related to pain/discomfort (N = 4; examples of an-swers: was painful; caused gagging, uncomforta-ble) or appointment issues (N = 2). Forty-six respond-ents (20%) had used the splint in the past, but were not using it anymore, while 75% of the respondents (N = 172) still used the bite splint. When asked how helpful the splint had been, 25 subjects reported that it had not been helpful at all, 9 that it was a little helpful, 37 were neutral, 49 respondents indi-cated that it had been helpful, and 95 that it had been extremely helpful.

The first objective of this study was to determine whether patients who use the occlusal splints would have more positive splint-related responses and a better oral health-related quality of life (ohrqol) compared to patients who did not use their splints. Table 2 provides an overview of the splint-related and the quality of life responses of these

two groups of patients. A factor analysis of the 14 MOHRQoL items showed that these responses loaded on two factors, namely a pain-related factor and a factor that can be described as a psycho-logical ohrqol factor. Separate MANOVAs were therefore computed for these two sets of ohrqol items. Table 2 shows that the main effect of the MANOVA with the 5 splint-related items was signifi-cant (F[10/318] = 2.991; p < 0.001) and that all five univariate analyses were significant as well. The patients who did not use the bite splint agreed less that their general status had improved since they got their splint, that the bite splint had a posi-tive effect and did not cause them discomfort, that they felt comfortable with their splint and liked us-ing the splint more than the subjects who used their splints.

The results of the MANOVA with the 8 pain-related items showed that the two groups differed significantly (main effect: F[16/180] = 2.175; p = 0.007). The uni-variate analyses showed that compared to the pa-tients who used their splint, the patients who did not use it at the time of the survey agreed more strongly with the items that their jaw joint caused them dis-comfort, that their facial pain kept them from enjoying life and interfered with their daily activities. The re-sults of the MANOVA for the six items concerning the psychological impact of having a splint showed a ten-dency for differences between the two groups. How-ever, the two groups did not differ significantly (main effect: F[12/320] = 1.654; p = 0.076).

The second objective was to explore whether the quality of the patient-provider relationship affects bite splint-related and ohrqol responses. Specifi-cally, it is of interest whether the informational quality of a patients relationship with their provider and/or the emotional quality of this relationship moderates these outcomes. Two questions were used to assess these two aspects of the patient-provider relationship. The first question referred to the emotional relationship by asking the patients to indicate their agreement with the statement I was satisfied with the way my dental provider treated me. The second item referred to the information flow between the provider and the patient. This item read My dental care provider who gave me the splint explained its use very well. Table 3 shows that a total of 21% of the respondents disa-greed strongly, disagreed or were neutral in their responses to both items, while 22% agreed and 58% agreed strongly with the first item, and 29% agreed and 51% agreed strongly with the second item. These responses were used to categorise the

Table 1 Overview of the respondents bite splint history

Bite splint related responsesFrequencies

N = 233 Percentages

When did you receive the bite splint?During the past year1 to 2 years ago2 to 3 years ago3 to 4 years ago4 to 5 years ago

16926130

6

8%1

45%30%15%3%

Why did you receive a bite splint?GrindingClenchingJaw painHeadaches

183120

8046

78%2

51%34%20%

Did you ever use your bite splint?I never used it.I used it in the past, but not now.I use it now.

1146

172

5%20%75%

Reasons for not using splint:Fitting issues Pain/uncomfortableWaste of moneyAppointment related issues

10422

If you used/use the bite splint, how helpful was/is it?Not at allA littleNeutralHelpfulExtremely helpful

259

374995

12%4%17%23%44%

1Percentages might not add up to 100% due to rounding. 2Percent-

ages add up to over 100% because the respondents could provide

more than one reason.

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Table 2 Quality of life responses (MOHRQoL) of patients who used vs did not use the bite splint

Splint related items1 No splint Splint p

My general status has improved since I got my splint. 2.72 3.80 < 0.001

My splint has a positive effect. 20.55 4.08 < 0.001

I feel comfortable with my splint. 2.11 4.08 < 0.001

I like using my splint. 2.19 3.24 < 0.001

My splint does not cause me discomfort. 1.35 3.12 < 0.001

Main effect: F(10/318) = 2.991 < 0.001

QoL: Pain / discomfort Cronbach alpha = 0.884)

OHRQOL scale items

My facial pain limits the kinds or amounts of food I eat. 2.29 1.98 0.247

My clenching habit causes discomfort. 3.12 3.45 0.209

My jaw joint causes me discomfort. 3.00 2.49 0.042

My facial pain causes me discomfort. 2.66 20.51 0.569

My facial pain makes me nervous. 2.09 1.84 0.263

My facial pain keeps me from enjoying life. 2.33 1.74 0.029

My facial pain interferes with my daily activities. 2.28 1.78 0.024

My facial pain affects my life in all of its aspects. 2.06 1.69 0.097

Main effect: F(16/180) = 2.175 0.007

QoL: Psychological impact (Cronbach alpha = 0.826)

It makes me nervous that I need a splint. 1.85 1.81 0.850

Having a splint keeps me from enjoying life. 1.68 1.48 0.246

Having a splint interferes with my intimate life. 2.13 1.85 0.223

Having a splint reduces my general happiness with life. 1.74 10.55 0.279

Having a splint affects all aspects of my life. 10.57 10.55 0.895

I would feel terrible about having to spend the rest of my life having a splint. 2.43 1.65 0.001

Main effect: F(12/320) = 1.654 0.076

1Answers ranged from 1 = disagree strongly to 5 = agree strongly.

Table 3 Responses concerning the relationship with the provider

Relationship with providerDisagree

and neutral AgreeStrongly

agreeMean

I was satisfied with the way my dental provider treated me. N=4621%

N=4822%

N=12958%

4.17

My dental care provider who gave me the splint explained its use very well.

N=4421%

N=6229%

N=10951%

4.12

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patients into three groups for each of the two items. In order to assess different degrees of emo-tional rapport between the patients and the provid-ers, the respondents who had disagreed or were neutral concerning the first statement were de-scribed as Not satisfied; patients who agreed with this first item were categorised as Satisfied and the subjects who had strongly agreed were de-scribed as Very satisfied. The responses of these three groups of patients are provided in Table 4.

Table 4 shows that the three groups differed sig-nificantly in their splint-related responses as pre-dicted. The group with the lowest level of satisfac-tion with their provider had the most negative splint-related responses and the most satisfied group had the most positive splint-related respons-es for each of the five items (main effect: F[10/318] = 2.991; p = 0.001). Concerning the quality of life related to pain and discomfort that the occlusal splint had caused, the MANOVA main

Table 4 Quality of life responses of patients who were not satised vs satised vs very satised with their provider

Splint related items1

Relationship with provider

pNot satised Satised Very satised

My general status has improved since I got my splint. 2.83 30.58 3.84 < 0.001

My splint has a positive effect. 2.97 3.75 4.05 < 0.001

I feel comfortable with my splint. 3.00 30.50 4.03 < 0.001

I like using my splint. 20.59 2.61 3.30 0.001

My splint does not cause me discomfort. 3.31 3.42 4.08 0.006

Main effect: F(10/318) = 2.991 0.001

QoL: Pain / discomfort

My facial pain limits the kinds or amounts of food I eat. 2.64 2.04 1.85 0.061

My clenching habit causes discomfort. 3.80 3.15 3.47 0.297

My jaw joint causes me discomfort. 30.52 3.04 2.69 0.068

My facial pain causes me discomfort. 3.20 2.82 2.30 0.030

My facial pain makes me nervous. 2.32 1.78 1.75 0.096

My facial pain keeps me from enjoying life. 2.49 2.04 10.51 0.002

My facial pain interferes with my daily activities. 2.32 2.19 10.51 0.003

My facial pain affects my life in all of its aspects. 2.44 1.82 1.40 0.001

Main effect: F(16/180) = 2.175; 0.007

QoL: Psychological impact

It makes me nervous that I need a splint. 1.84 2.05 1.62 0.117

Having a splint keeps me from enjoying life. 1.71 1.84 1.37 0.031

Having a splint interferes with my intimate life. 1.92 2.43 1.65 0.005

Having a splint reduces my general happiness with life. 1.66 1.76 10.50 0.389

Having a splint affects all aspects of my life. 1.61 1.43 10.54 0.738

I would feel terrible about having to spend the rest of my life having a splint.

1.61 1.92 1.74 0.474

Main effect: F(12/320) = 1.654; 0.076

1Answers ranged from 1 = disagree strongly to 5 = agree strongly.

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effect was significant as well. However, the univari-ate analyses showed that this significant main ef-fect was mostly due to the responses to four of the eight single items. These four items addressed the degree to which the facial pain caused patients dis-comfort, kept them from enjoying life, interfered with their daily activities and affected their life in all of its aspects. As predicted, the group that was very satisfied with their emotional relationship with their provider had the most positive responses to each of these items.

Concerning the patients quality of life related to the psychological impact of the bite splint, the MANOVA showed that there was only a tendency for the three groups to differ (F[12/320] = 1.654; p = 0.076). The significant univariate analyses showed that the answers to the statements Hav-ing a splint keeps me from enjoying life and Hav-ing a splint interferes with my intimate life differed as predicted, with the patients who were very satis-fied with their providers having the most positive ohrqol responses.

While Table 4 provides an overview of the effect of the emotional quality of the patient-provider in-teraction, Table 5 focuses on whether the quality of the information given by the provider to the patient about the splint affected the bite splint-related and ohrqol responses. The results of the MANOVA showed that there was a tendency that the bite splint-related responses of the three groups dif-fered as predicted (F[10/312] = 1.807; p = 0.059): the subjects whose provider had not explained the bite splint well showed the least positive respons-es and the subjects whose provider had explained it very well showed the most positive responses. However, the main effects of the MANOVAs with the pain-related QHRQoL scores and the psycho-logical impact related OHRQoL scores were not sig-nificant. This finding indicates that the quality of the providers explanations about the bite-splint did not affect the patient-related outcomes.

One additional set of analyses was conducted to explore whether the patients demographic background characteristics, specifically their gen-der and age, would affect their bite splint-related and ohrqol responses. Three linear multiple re-gression analyses were computed with the aver-age bite splint-related response scores and the average pain-related and psychological impact-re-lated ohrqol scores as the three dependent varia-bles. Neither the patients gender nor their age was a significant predictor of any of these three variables.

DISCUSSION

While bite splints are not necessarily a treatment for the actual causes of patients bruxing habits, they can definitely have a positive effect on pa-tients dental health (Macedo et al, 2007). One question that had not been explored so far is wheth-er using a splint will also improve patients oral health-related quality of life. This study therefore explored how patients who still use their bite splint differed in their bite splint-related responses and ohrqol from patients who had discontinued the use of their occlusal splint. One might argue that the respondents who were no longer using the splint were those patients who had no symptoms and thus discontinued the bite splint use because they did not think they needed it any more. However, the data showed that the opposite effect was found: Patients who used the bite splint were significantly more likely to report that their status had improved since receiving their bite splint compared to pa-tients who had discontinued its use. In addition, the users also had a significantly more positive pain-related ohrqol and a tendency to have a more posi-tive psychological impact-related ohrqol compared to the non-users. This finding is important because it should draw dentists attention to the fact that when patients with bruxism use a bite splint, it will not only improve their dental health (Macedo et al, 2007), but it will also have a positive effect on their ohrqol. The finding that the main effect of the MANOVA with the dependent variable psychological impact-related ohrqol was not significant might be due to the fact that most patients use their splint at night and thus do not see their daily lives as affect-ed by its use. Using an ohrqol instrument that ena-bles differentiation of aspects of patients ohrqol such as the MOHRQoL allowed a more differentiated understanding of the ohrqol outcomes of using an occlusal splint for patients with bruxism.

The 14-item MOHRQoL instrument was devel-oped as an alternative to the Oral Health Impact Profile (OHIP) by Slade and Spencer (1994) and its short version, the OHIP-14 (Slade, 1997), which are the instruments most widely used for assessing ohrqol in adults. The MOHRQoL-A scale is an alter-native measure of ohrqol in adults that was devel-oped based on three considerations. First, this in-strument was constructed in response to the theoretical considerations concerning the underly-ing four components of ohrqol (Inglehart and Bagra-mian, 2002b). The MOHRQoL-A therefore includes questions concerning how oral health affects pa-

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tients functioning (such as their chewing), their psy-chological as well as their social well-being and the degree to which it causes pain and discomfort. Be-ing able to compute subscores of patients ohrqol is possible because of the way this scale was con-structed. The second consideration was that it should be possible to use the scale in a disease/treatment specific manner. For example, Henson et al (2001) replaced the general words at the begin-ning of the 14 statements My teeth and gums with

the term My dry mouth when they assessed the ohrqol related to having xerostomia. Gray et al (2002) replaced these words with My dentures in their study of the ohrqol of denture patients. In this study, the terms My facial pain and Having a splint were used to make it a treatment-specific scale. The third consideration was that using the answer for-mat should be easy for patients who could not see the answer scale either because they responded to the survey in a telephone interview or because they

Table 5 Quality of life responses of patients whose provider did not explain the bite splint well vs explained it well vs explained it very well

Splint related items

Provider explained

pNot well Well Very well

My general status has improved since I got my splint. 3.00 3.64 3.79 0.004

My splint has a positive effect. 3.10 3.89 3.99 0.002

I feel comfortable with my splint. 2.97 3.82 3.95 < 0.001

I like using my splint. 20.57 2.93 3.24 0.027

My splint does not cause me discomfort. 3.30 3.84 3.97 0.078

Main effect: F(10/312) = 1.807 0.059

QoL: Pain / discomfort

My facial pain limits the kinds or amounts of food I eat. 2.24 2.06 2.05 0.844

My clenching habit causes discomfort. 30.52 3.65 3.28 0.560

My jaw joint causes me discomfort. 3.12 3.06 2.85 0.734

My facial pain causes me discomfort. 2.80 2.85 2.43 0.383

My facial pain makes me nervous. 2.12 1.65 1.98 0.245

My facial pain keeps me from enjoying life. 2.24 1.85 1.73 0.210

My facial pain interferes with my daily activities. 2.16 1.88 1.75 0.352

My facial pain affects my life in all of its aspects. 2.24 1.77 10.50 0.037

Main effect: F(16/180) = 1.099 0.359

QoL: Psychological impact

It makes me nervous that I need a splint. 1.81 1.84 1.73 0.855

Having a splint keeps me from enjoying life. 1.64 10.54 10.51 0.827

Having a splint interferes with my intimate life. 1.81 2.16 1.77 0.199

Having a splint reduces my general happiness with life. 10.53 10.54 1.62 0.872

Having a splint affects all aspects of my life. 10.50 1.34 1.63 0.241

I would feel terrible about having to spend the rest of my life having a splint. 1.67 1.62 1.89 0.371

Main effect: F(12/314) = 1/107 0.353

1Answers ranged from 1 = disagree strongly to 5 = agree strongly.

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have health literacy issues. The MOHRQoL items were thus scored as a 5-point Likert scale from 1 = disagree strongly to 5 = agree strongly.

In addition to showing for the first time that pa-tients who use an occlusal splint perceive their splint as rather positive and have a more positive pain-related quality of life than non-users, the sec-ond contribution of this study is that it draws atten-tion to the fact that building rapport and establish-ing a positive relationship with patients clearly contributes to the success of their treatment. Con-sistent with previous research that analysed the impact of positive patient-provider communication on patients satisfaction with their provider (Son-dell et al, 2002; Shouten et al, 2003; Okullo et al, 2004; Kim et al, 2012), reducing patients dental fear and anxiety (Corah et al, 1985; Hottell and Hardigan, 2005), increasing patients confidence in their dentist (Corah et al, 1988; van der Molen et al, 2004), and on achieving more positive treat-ment outcomes (Carey et al, 2010), the findings of this study also showed that the more satisfied the patients were with their provider, the more positive-ly they related to bite splints and the more their splints had positively affected their quality of life in terms of experiencing pain and discomfort. Howev-er, consistent with the findings by Patel et al (2006), the emotional aspect of the relationship was again more important in shaping patient responses than the purely informational aspect. While the patients who were strongly satisfied with their providers dif-fered as predicted in their bite splint-related as well as pain-related ohrqol responses from those pa-tients who were less satisfied with their providers, the differences in the degree to which patients per-ceived to be informed by their providers did not af-fect the outcomes to the same degree. This finding is important because it shows that merely provid-ing all information about a dental treatment might not have as much an effect on patients treatment cooperation and thus on their oral health and qual-ity of life over time as having a positive relation-ship. One might argue that providing all information is necessary but not sufficient for an optimal pa-tient-provider relationship and patients treatment cooperation. Having a positive rapport is ultimately most influential concerning the outcomes of this type of treatment. Future research should there-fore explore whether the quality of the patient-pro-vider relationship is also a crucial factor in motivat-ing patients for other behavioural changes related to increasing patients oral health and preventing dental disease.

This study had several limitations. First, the data were collected from patients who had received their bite-splint treatment from a student in a dental school clinic. While these students were closely su-pervised by licensed faculty members, one could po-tentially argue that receiving a bite splint from a den-tist in a private practice setting might be a different situation. Dentists obviously are more experienced with providing this type of treatment which might have resulted in more positive splint-related respons-es. However, the fact that Lindfors et al (2011) found that the percentage of patients in their study who still used their interocclusal appliances was similar to the percentage in this study provides some support for the assumption that comparability is given.

A second limitation is that no control group of patients without bruxing habits and bite-splint use were included as a control group in this study. The ohrqol responses can therefore only be interpreted by relying on the comparisons between the differ-ent clinical groups in this study. It is not possible to draw any conclusions concerning how good or bad the quality of life of these patients was in compari-son to patients in general.

The final and most important limitation, however, was that this retrospective study did not allow using any data from the patients clinical charts or directly from clinical exams due to privacy concerns. Future research should therefore be prospective and ana-lyse the responses of patients who consent to have their clinical records reviewed as well.

CONCLUSION

The findings of this study showed that a majority of patients who received an occlusal splint continued to use it. More importantly, these findings showed that patients who used their splint had significantly more positive splint-related responses and a more positive pain-related quality of life. This finding should alert clinicians to the importance of considering occlusal splints in the treatment of patients with bruxism.

In addition, the present data clearly point to the importance of understanding the role of patient-provider communication on patients willingness to cooperate with treatment recommendations con-cerning the use of an occlusal splint. It is important that clinicians be aware of the fact that merely pro-viding information about a treatment might not af-fect their patients treatment cooperation as much as the emotional quality of the patient-provider re-lationship. Taking the time to listen to patients, af-

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258 Oral Health & Preventive Dentistry

firming any treatment-related cooperation efforts and reflecting on the positive consequences of treatment cooperation can contribute to building a satisfying relationship with patients that will have a positive effect on the patients treatment decision making and treatment outcomes.

ACKNOWLEDGEMENTS

We want to thank the staff at the University of Michigan, Ofce of Patient Services and especially Ms. Georgia Kasko for their clerical support with mailing the surveys, and Maria Maddalena Barczynski for her help with preparing the data for analyses and her support with preparing the tables.

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