Impact of mandibular implant prostheses on the oral health-related quality of life in partially and completely edentulous patients

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1 Norsiah Yunus Mohd Masood Roslan Saub Ashwaq Ali Tara Bai Taiyeb Ali John Mark Thomason Impact of mandibular implant prostheses on the oral health-related quality of life in partially and completely edentulous patients Authors affiliations: Norsiah Yunus, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia Mohd Masood, Centre of Population Oral Health & Clinical Prevention Studies, Faculty of Dentistry, Universiti Teknologi MARA, Shah Alam, Selangor, Malaysia Division of Population & Patient Health, Dental Institute, King s College London, London, UK Roslan Saub, Department of Community Oral Health and Clinical Prevention, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia Ashwaq Ali, Tara Bai Taiyeb Ali, Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia John Mark Thomason, School of Dental Sciences, Newcastle University, Newcastle upon Tyne, UK Corresponding author: Norsiah Yunus Department of Restorative Dentistry, Faculty of Dentistry University of Malaya Kuala Lumpur, Malaysia Tel.: Fax: norsiah@um.edu.my Key words: fixed partial prostheses, implant overdenture, mandibular implants, Oral Health Impact profile, posterior edentulism Abstract Objective: To assess the oral health-related quality of life (OHRQoL) of patients provided with mandibular implant fixed partial prostheses () for rehabilitation of two adjacent missing posterior teeth and complete denture patients provided with mandibular implant-supported overdenture (). The response to change in OHRQoL with implant prostheses was additionally compared. Material and methods: In this prospective study, 20 (mean age 47.0; SD 12.9 years) and 28 (mean age 61.5; SD 9.1 years) patients received 2 mandibular implants. Metal ceramic nonsplinted fixed prostheses were provided in group, while in group, the mandibular overdentures were retained by nonsplinted attachments. Patients rated their oral health-related quality of life using OHIP-14 Malaysian version at baseline (T0), 2 3 months (T1) and 1 year (T2) postimplant treatment. Mean OHIP-14 for total and domain scores between groups and intervals was analysed using repeated-measures ANOVA and t-test. Mann Whitney and Wilcoxon signed rank tests were used for the comparison of mean score change and effect size, while the association between pre- and post-treatment scores was determined using multivariate linear regression modelling. Results: The total OHIP and domain scores before implant treatment were significantly higher (lower OHRQoL) in than in groups, except for physical pain where this domain showed similar impact in both groups. Postimplant scores between groups at T1 and T2 showed no significant difference. The mean score changes at T0 T1 and T0 T2 for total OHIP-14 and domains were significantly greater in except in the domains of physical pain and disability which showed no difference. Large effect size (ES) was observed for total OHIP-14 in while moderate in. Improved OHRQoL was dependent on the treatment group and pretreatment score. Conclusion: Improvement in OHRQoL occurred following both mandibular implant-supported overdentures and implant fixed partial prostheses. Date: Accepted 13 June 2015 To cite this article: Yunus N, Masood M, Saub R, Ali A, Taiyeb Ali TB, Thomason JM. Impact of mandibular implant prostheses on the oral health-related quality of life in partially and completely edentulous patients. Clin. Oral Impl. Res. 00, 2015, 1 6 doi: /clr Dental rehabilitation of partially and completely edentulous patients with oral implants is a valid method for restoring function for its predictable survival rate and favourable prosthetic outcomes (Lindquist et al. 1997; Lekholm et al.1999; Buser et al. 2002). These clinical parameters alone, however, do not provide complete information on the success of the treatment. Patient-reported outcome measures should complement these other measures and, in addition, be used to detect changes in patient s health status in response to any intervention (Naito et al. 2006; Kimura et al. 2012). OHRQoL is an effective and widely used instrument to measure the impact of treatment from the patients point of view. It is a subjective perception of an individual about oral health, and the assessment provides better and deeper insight into the patients perspective (Locker 1988; Sischo & Broder 2011). Among many instruments, the Oral Health Impact profiles (Slade & Spencer 1994) have been used to assess the effect of implant treatment among different edentulism status (Awad et al. 2000, 2014; Allen et al. 2006; OZhayat 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd 1

2 & Gotfredsen 2012; Petricevic et al. 2012; Preciado et al. 2012; Emami & Thomason 2013; Emami et al. 2015), with high sensitivity to detect dissatisfaction with prosthetic rehabilitation (Preciado et al. 2012; Montero et al. 2013). The original OHIP-49 developed by Slade & Spencer (1994) covered seven domains and was based on theoretical concept that oral condition can produce physical, social and psychological effects that can affect an individual s normal functioning. The shortened version of OHIP-14 was developed to address the same concept and to reduce response time (Slade 1997; Locker & Allen 2002; John et al. 2006). Currently, most of the research assessing the impact of implant therapy has focussed on comparing the OHRQoL provided by implant retained overdenture vs. conventional complete dentures with high level of evidences demonstrating better quality of life with implant overdentures (Awad et al. 2000, 2003; Melas et al. 2001; Harris et al. 2013; Zembic & Wismeijer 2013). Reviews on treatment protocol and clinical concerns related to overdenture application are available (Walton et al. 2002; Andreiotelli et al. 2010; Stoumpis & Kohal 2011). On the other hand, there has been less focus on patient-based outcome measure in implant therapy among partially dentate subjects, with a recent systematic review revealing lack of standardized reliable and validated assessment instruments employed in these studies (de Souza et al. 2014). Despite the limited evidence, available studies in partially dentate patients comparing implant and conventional fixed and removable prostheses were mainly conclusive in favour of implant therapy (Furuyama et al. 2012; Petricevic et al. 2012). Patients reported improved satisfaction and well-being (Abu Hantash et al. 2006), with some even regarded implant prostheses as their own natural teeth (De Bruyn et al. 1997). While completely edentulous condition negatively impacts OHRQoL through the inability to chew, poor speech and pain (Walton et al. 2002), the psychological dissatisfaction was an important factor in partially dentate patients (Nickenig et al. 2008). There were limited studies comparing the impact of implant treatment on these different oral conditions, hence substantiating the need for additional studies related to OHRQoL. Therefore, the aim of this prospective study was to assess and compare the effect of and on the patients OHRQoL and the response to change after 2 3 months and 1 year postimplant insertion. Material and methods Patients were consecutively selected from the waiting list at the Faculty of Dentistry, University of Malaya, for rehabilitation of missing teeth. Inclusion criteria for partially dentate patients include those with two adjacent missing posterior mandibular teeth on one side of the arch. The contralateral posterior and opposing maxillary arch were completely dentate or had been restored with tooth and/or implants fixed prostheses. As these patients were unwilling to accept removable prostheses, they allowed a perfect opportunity to compare the most meaningful treatment alternatives than those of implant intervention or no prosthesis. This avoided complications of comparison with the additional variable of a removable partial denture. Nonsurgical periodontal treatment, restoration of carious teeth or replacement of defective restoration were provided when indicated. Patients with insufficient bone height that restricted the insertion of two 6- to 8-mm length short implants were excluded. Selection criteria for completely edentulous included patients with at least 6 months experience wearing complete dentures and have sufficient anterior alveolar ridge height for implant placement of at least 9.5 mm length. Patients were provided with instructions about the study and written consent obtained. Implant treatment was offered at very minimal or no cost at all. The Ethical Committee, Faculty of Dentistry, University of Malaya, approved the study. Implants were placed following a two-stage surgery. For group, nonsplinted metal ceramic prostheses were cemented 2 3 weeks after abutment connection. In group, two implants were placed in the parasymphyseal region and 1 2 weeks after abutment connection, the mandibular complete dentures were converted into following the intra-oral pick-up procedure (Yunus et al. 2014). Seventeen patients received telescopic attachment, while 11 had Locator attachments for denture retention. The OHRQoL was evaluated using a shortened Malaysian version of Oral Health Impact Profile-14 where the validity and reliability of this instrument have been tested (Saub et al. 2007). The questionnaire consisted of 14 items covering seven domains: functional limitation, physical pain, psychological discomfort, physical disability, social disability and handicap. The total score ranges between 0 and 56 with a lower score indicating a better OHRQoL. A guided selfadministered questionnaire was used to acquire information at the following intervals: before implant (T0), 2 3 months (T1) and 1 year (T2) postimplant prostheses insertion. To reduce bias, questionnaires were collected independently from the treating operators involved in providing surgical and prosthodontic treatments. Statistical analyses The one-year numeric data of patient-generated responses from the OHIP-14 of prospective longitudinal studies were compiled. Data were analysed using R-Project statistical software, Version (Alcatel-Lucent Technologies, Murray Hill, NJ, USA) (Team 2012), and the significant level was set at P < Data analyses included descriptive statistics for total patient sample and according to the two treatments groups. Mean OHIP-14 scores over time was analysed using parametric repeated-measures ANOVA, between-group comparison at each interval made using independent t-test. The Mann Whitney U-test was employed to compare the mean change in OHIP-14 score between two different intervals. Within-group comparison over time was analysed using Friedman test with post hoc Wilcoxon signed rank test and Bonferroni correction. The calculation of effect size (Cohen 1988) was performed to determine the strength of change between any two intervals and for meaningful comparison of the magnitude of changes between the two groups, using a procedure recommended by Cohen s criteria. According to Sullivan & Feinn (2012), both the P-value (statistical significance) and the effect size (substantiative significance) are essential information when interpreting the results. The difference in OHIP-14 scores between any two intervals was calculated and divided by the standard deviation of the first/ initial score to give ES. The ES of <0.5 is considered to be small, is moderate and >0.8 is large. Multivariate linear regression modelling was used to determine the association between pretreatment total OHIP-14 and post-treatment scores after controlling for baseline OHIP-14 scores. Results A total of 48 patients were enrolled and depending on the edentulous status, each received 2 mandibular implants, with 20 patients provided with and 28 with. The mean age of ( years) was significantly higher 2 Clin. Oral Impl. Res. 0, 2015 / John Wiley & Sons A/S. Published by John Wiley & Sons Ltd

3 Table 1. Descriptive analysis of total patient sample and according to treatment groups Total (n=48) than the ( years) with no significance difference in gender between the two groups (Table 1). The mean OHIP-14 scores in the two treatment groups at pretreatment baseline (T0), 2 3 months (T1) and 1 year (T2) post-treatment is shown in Table 2. Repeated-measures ANOVA showed OHIP-14 and its domains scores to be significantly different within group with time; however, no significant difference between groups was observed for most domains. Significant interaction between treatment groups and time (P < 0.001) for total OHIP-14 and domain scores except the physical pain domain indicated a marked difference in response of the (n=20) (n=28) P-value Gender Male n (%) 13 (27.1) 6 (30) 7 (25) a Female n (%) 35 (72.9) 14 (70) 21 (75) Age (mean SD) years years b Tooth loss pattern Unilateral distal extension 15 (75%) Unilateral bounded space 5 (25%) Completely edentulous 28 (100%) a Chi-square test; b t-test (P < 0.05). two groups at different intervals with intervention. Between-group comparison for each interval showed significant difference only at baseline (T0) for total OHIP-14 score, with significantly higher score (lower OHRQoL) in group. For domain scores, significantly higher values were also observed in group at baseline except for physical pain where this domain showed similar impact in both groups. The change in total OHIP-14 scores from T0 T1 and T0 T2 (Table 3) showed significantly greater change in than that in groups, indicating greater improvement in oral health-related quality after implant treatment in partially dentate patients. Significantly greater score change was also observed in individual domains in this group except for physical pain and physical disability. The score change after implant intervention (between T1 and T2) was not significantly different in both groups. The ES for total OHIP-14 and most domains was significantly large between baseline to T1 and baseline to T2 within group. Similarly for group, the ES was significant but moderate for total OHIP- 14 score, while most other domains scores were not significant. The two domains in which had significant and large ES values were physical pain and physical disability, at T1 and T2 relative to baseline (Table 4). The multivariate models Models 1, 2, 3 and 4 explained about 6%, 15%, 4% and 19% of the total variance, respectively (Table 5). All models were adjusted for age and gender with Models 2 and 4 adjusted for baseline OHIP-14 score. The models illustrated that improved OHRQoL at 1 year after implant treatment as measured with the OHIP-14 was dependent on the treatment group and on the pretreatment OHRQoL of the person. However, the improvement in Table 2. Mean OHIP-14 and domain scores (SD) at intervals: baseline (T0), 2 3 months (T1) and 1 year (T2) post-treatment; and comparison within and between groups Repeated-measures ANOVA Within Between (T0) (T1) (T2) (T0) (T1) (T2) group groups Group 9 Time OHIP Domain Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) P-value P-value P-value Functional limitation 3.95 (2.16)* 1.50 (1.50) 0.53 (0.84) 2.41 (1.22)* 1.67 (1.59) 1.56 (1.60) < Physical pain 3.75 (1.59) 2.15 (1.50) 1.53 (1.17) 3.41 (1.62) 1.78 (1.55) 1.63 (1.55) < Psychological discomfort 4.55 (2.06)* 2.35 (1.39) 2.16 (1.26) 2.41 (1.91)* 1.96 (1.70) 1.78 (1.78) < Physical disability 3.80 (2.35)* 1.75 (1.37) 0.95 (1.18) 2.44 (1.53)* 1.44 (2.06) 1.04 (1.60) < Psychological disability 2.75 (1.89)* 0.95 (1.36) 0.32 (0.75) 1.04 (1.87)* 0.78 (1.48) 0.33 (1.00) < Social disability 2.15 (2.46)* 0.65 (1.09) 0.05 (0.23) 0.59 (1.42)* 0.59 (1.53) 0.15 (0.46) < Handicap 3.60 (2.35)* 1.50 (1.28) 0.89 (0.74) 1.07 (1.94)* 0.74 (1.53) 0.81 (1.36) < OHIP total (12.90)* 9.94 (6.40) 6.42 (3.37) (9.04)* 8.96 (9.77) 7.57 (5.50) < *Significance between groups at T0 (baseline) using independent t-test (P < 0.05). Table 3. Between-group comparisons of change in mean OHIP-14 scores (SD) between intervals; baseline (T0), 2 3 months (T1) and 1 year (T2) posttreatment T0 T1 T1 T2 T0 T2 OHIP Domain Mean (SD) Mean (SD) P-value Mean (SD) Mean (SD) P-value Mean (SD) Mean (SD) P-value Functional limitation 2.5 (1.96) 0.7 (1.48) 0.005* 0.8 (1.64) 0.1 (1.49) (2.67) 0.8 (1.55) * Physical pain 1.6 (1.43) 1.6 (1.90) (1.39) 0.1 (1.48) (1.75) 1.7 (1.69) 0.46 Psychological discomfort 2.2 (2.28) 0.4 (2.01) 0.006* 0.1 (1.13) 0.1 (1.56) (2.12) 0.6 (1.9) 0.006* Physical disability 2.1 (2.44) 1.0 (1.59) (1.11) 0.4 (1.81) (2.61) 1.4 (1.94) Psychological disability 1.8 (2.21) 0.3 (1.40) 0.007* 0.5 (0.90) 0.4 (1.03) (2.09) 0.7 (1.71) * Social disability 1.5 (2.69) 0.0 (1.59) 0.023* 0.4 (0.77) 0.5 (1.30) (2.57) 0.5 (1.39) 0.004* Handicap 2.1 (2.79) 0.3 (1.64) 0.011* 0.5 (1.35) 0.2 (1.58) (2.42) 0.3 (1.34) * OHIP total 13.7 (13.60) 4.4 (8.50) 0.006* 3.5 (5.40) 1.4 (7.30) (13.5) 6.0 (7.04) * *Significance using Mann Whitney U-test (P < 0.05) John Wiley & Sons A/S. 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4 Table 4. Effect size (ES) for OHIP-14 score change and within-group comparison of score between intervals; baseline (T0), 2 3 months (T1) and 1 year (T2) post-treatment OHIP Domain (T0 T1) (T1 T2) (T01 T2) (T0 T1) (T1 T2) (T01 T2) Functional limitation Physical pain Psychological discomfort Physical disability Psychological disability Social disability Handicap OHIP total OHRQoL at 2 3 months after implant was only dependent on pretreatment OHRQoL of the individual. Discussion Effect size was calculated using formula: [(m1 m2)/sd1]. Table 5. Multivariate model to determine whether pretreatment OHIP-14 score has an influence on post-treatment score; baseline (T0), 2 3 months (T1), and 1 year (T2) post-treatment OHIP-14 at T1 The advantage of using OHIP to measure the impact of oral health problems and intervention is that it is a disease-specific instrument, and the Short form OHIP-14 questionnaires (Slade 1997) are effective at measuring the oral health impact of edentulous and the prosthesis users (Zucoloto et al. 2014; Kuoppala et al. 2013; de Souza et al. 2012). The items in the questionnaire covered the seven domains related to problems with the teeth, mouth and prostheses (Slade 1997). The results of this study revealed that partially dentate patients with missing mandibular posterior teeth reported more impaired OHRQoL at baseline compared to edentulous complete denture wearers about to be treated with implant to support mandibular overdentures. This was in contrast to the findings by Montero et al. (2013), where they found partial denture candidates to be less affected by their oral health problems. The contrasting results could be due to the fact that their OHIP-14 at T2 Model 1 Model 2 Model 3 Model 4 B SE B SE B SE B SE Intercept Treatment group Reference group * Baseline OHIP-14 Score (T0) * R 2 = 0.06 R 2 = 0.15 R 2 = 0.04 R 2 = 0.19 All the models were adjusted for age and gender. Model 2 and Model 4 were adjusted for Baseline OHIP-14 scores.*indicates significant at P < assessment was for conventional prosthodontic therapy without implant intervention and different clinical indications could have been used for toothborne fixed partial denture patients which usually involved shortbounded edentulous span. In this study, about three-quarter of partially dentate patients had unilateral distal extension edentulous space, with majority had missing first and second molars. While the edentulous group enrolled in the present was already wearing technically adequate set of complete dentures, partially dentate patients had no recourse to removable partial dentures at the time they completed baseline questionnaires. Previous study has shown that patients without recourse to removable prostheses had poorer QOL compared to those provided with the prostheses (McGrath & Bedi 2001). Nevertheless, both treatment groups recorded significant improvement in OHR- QoL scores at 1 year. There was greater score change observed with as move from no prosthesis, but less change with as a move to a more retentive and stabilized prosthesis. Interpreting this finding is open to some conjecture as although the 2 scenarios reflect the common finding viz partially edentulous patients often electing not to wear a removable prosthesis unless they replaced anterior teeth (Jepson et al. 1995) but the edentulous patient wearing the complete prosthesis (often for social rather than functional reasons) prior to conversion to. Locker et al. (2004) suggested an estimated minimally important difference (MID) for OHIP-14 of 5 point, which is the smallest difference in score which is being perceived as being clinically significance. At 1 year, the magnitude of improvement in group was 6 points compared to 18 points in. Considering this, it can be implied that implant intervention was perceived by patients as beneficial in both treatment groups in the present study. However, it needs to be mentioned that the MID values for the OHIP-14 Malaysian version has yet to be determined. This observation was supported by observations of effect size where ES values that are large or very large (Cohen 1988) when considering changes between T0 T1 and T0 T2 in the group. By contrast, in the group, large effects were confined to the domains of Physical Pain and Physical Disability and small or moderate effects in the other domains. The effect of implants fixed prostheses in partially dentate patients was quite overwhelming where improvement was already evident with 13 points, immediately after implant therapy with further significant improvement at 1 year compared to baseline. Aarabi et al. (2014) did not observe improvement of OHRQoL immediately but only after a year in their patients treated with conventional fixed prosthesis therapy. It could be that patients adapted faster to implant compared to conventional fixed prostheses. The improvement shown in group was in agreement with earlier finding (Petricevic et al. 2012) that enrolled patients of similar inclusion criteria, which was missing posterior teeth and fully dentate in the opposing jaw. Regarding, the results of this study are similar to the existing evidence where OHRQoL improved following delivery of implant support overdentures (Awad et al. 2000; Thomason et al. 2003; : Harris et al. 2013; Awad et al. 2014). In relation to the estimates of ES, which is one of the distribution-based approach towards identifying differences likely to be clinically meaningful, Emami et al. (2015) observed large magnitude of treatment effect with implant overdenture, while in this study, the effect was moderate. Improvement in the domains of physical pain and physical disability was large and concurred with previous study where these two domains showed most changes after implant 4 Clin. Oral Impl. Res. 0, 2015 / John Wiley & Sons A/S. 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5 (Awad et al. 2000, 2003). Physical pain related to sore spots and discomfort related to dentures or teeth while physical disability related to unsatisfactory diet and interrupted meals. Other domains such as psychological, social and handicap were not significantly impacted. It could be either that edentulous patients did not perceive as being disadvantaged in this respect (Harris et al. 2013) or patients had already reported the lowest possible value with their recently constructed complete dentures, and hence, there was no room for further improvement. On the other hand, large treatment effect (ES) was seen across all domains in group and as observed by Montero et al. (2013), those with higher perceived impairment would show greater increase in OHRQOL after rehabilitation. The multivariate regression analysis in this study similarly showed that post-treatment improvement with implants intervention could be predicted based on their baseline perceptions. While OZhayat & Gotfredsen (2012) found younger age to be associated with larger change in OHRQoL, age was not a factor in this study. The different findings could be due to the fact that their study ( OZhayat & Gotfredsen 2012) compared treatment effect between conventional fixed and removable prostheses while the present study involved rehabilitation using implant therapy. It is acknowledged that the mean age of the two groups was dissimilar, as edentulous patients were expected to be from an older age group. However, this factor had been adjusted in the multivariate regression analysis when determining the effect of treatment type on OHIP-14 score. And in relation to the treatment type, the intervention was also not an alternative option for the patients, as no patient from the group would qualify for the treatment and vice versa. It was also important to realize that implant treatment to the different groups was of different modalities; however, the results of this study provide a unique data on the changes in patients perception of their oral conditions with implant prostheses. The results should provide the clinician with some evidence regarding relative benefits of implant rehabilitation when planning the treatment with patient, and in relation to public health care, implant interventions could be prioritized to the group which benefits more. However, further studies should also include comparison of outcomes with conventional tooth-supported prostheses or removable partial prostheses with longer follow-up periods and larger sample size. Future studies might also include implant rehabilitation in the aesthetic zone, considering that the location of missing teeth have significant predictor variables (Kimura et al. 2012). Some of the limitations of this study include that patients were recruited from only a University teaching clinic, implant treatments were provided with minimal costs and the relatively small sample size especially in the group. The group was not homogenous in relation to missing tooth pattern but was homogeneous in that they were partially dentate. Sampling of only distal extension edentulous spaces would have reduced the sample size and decreased power; hence, patients with bounded edentulous space with two adjacent missing teeth were also enrolled into the study. However, these cases were much smaller in number relative to those with unilateral distal extension edentulous spaces. Blinding was not possible in the clinical procedures, while data on other sociodemographic factors such as education level and income were not collected in this study. Inclusion of these factors may modify the perception on their quality of life. Therefore, the results of this study should be interpreted in the light of these limitations. Conclusion Improvement in oral health-related quality occurred following both mandibular implantsupported overdentures and implant fixed partial prostheses. The magnitude of statistical change and the effect size was larger among those who received mandibular implant fixed partial prosthesis in more attributes of oral health-related quality of life. Acknowledgements: This study was supported by the UMRG (RG059-09HTM) and HIR Grant (UM.C/625/1/HIR/MOE/ DENT/12), University of Malaya, Kuala Lumpur. The authors reported no conflict of interests related to the study. References Aarabi, G., John, M.T., Schierz, O., Heydecke, G. & Reissmann, D.R. (2014) The course of prosthodontic patients oral health-related quality of life over a period of 2 years. Journal of Dentistry 43: Abu Hantash, R.O., Al-Omiri, M.K. & Al- Wahadni, A.M. 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