Tanta Dental Journal

ORIGINAL ARTICLE
Year
: 2017  |  Volume : 14  |  Issue : 4  |  Page : 173--180

Bite force and oral health impact profile in completely edentulous patients rehabilitated with two different types of denture bases


Hassan M Sakr1, Mostafa Fayad2,  
1 Department of Removable Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt
2 Department of Removable Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt; Department of Removable Prosthodontics, College of Dentistry, Taibah University, Medina, Saudi Arabia

Correspondence Address:
Mostafa Fayad
Department of Removable Prosthodontics, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt

Abstract

Purpose The aim of this study was to evaluate bite force and oral health impact profile (OHIP) in completely edentulous patients rehabilitated with two different types of denture bases. Patients and methods A total of 26 patients were selected from outpatient clinic, Removable Prosthodontic Department, Al-Azhar University. For each patient two types of complete dentures were made: (a) a heat-polymerizing hard Polymethyle-methacrylate (PMMA) and (b) thermoplastic PMMA. Bite force were evaluated 1 month and 6 months after denture insertion. Oral health-related quality of life was measured after 6 months of denture use using modified OHIP scale for edentulous patients. The data were statistically analyzed using statistical package for the social sciences V21 software. Results After 6 months of denture insertion, the bite force with a thermoplastic PMMA was better than that of heat-polymerizing hard PMMA with statistically significance difference. After 6 months, the OHIP for thermoplastic PMMA recorded better values more than a heat-polymerizing hard PMMA. Conclusion A thermoplastic PMMA denture was found to significantly has better maximum bite force values and OHIP after 6 months of denture use as compared to heat-polymerizing hard PMMA complete dentures.



How to cite this article:
Sakr HM, Fayad M. Bite force and oral health impact profile in completely edentulous patients rehabilitated with two different types of denture bases.Tanta Dent J 2017;14:173-180


How to cite this URL:
Sakr HM, Fayad M. Bite force and oral health impact profile in completely edentulous patients rehabilitated with two different types of denture bases. Tanta Dent J [serial online] 2017 [cited 2018 May 25 ];14:173-180
Available from: http://www.tmj.eg.net/text.asp?2017/14/4/173/221383


Full Text

 Introduction



Modern dentistry offers many options for the restoration of completely edentulous mouth, like complete dentures and implant retained over denture. Complete dentures became very popular many decades ago with the introduction of acrylic polymers in dentistry. Many patients choose complete dentures due to factors as relatively high cost of dental implant [1].

Studies have shown that when compared with natural dentition participants, denture wearers suffer from a decline in bite force and masticatory efficiency [2],[3],[4]. When people age, their muscles undergo functional changes, mainly through atrophy and tooth loss [5].

Considering the constant increase in elderly people all over the world, it has become essential to evaluate bite force and muscle changes associated with age [6],[7]. Bite force is an important variable to investigate oral function [8]. Maximum bite force (MBF) also directly influences diet choice, which has an important role in the maintenance of masticatory function [9]. The old people with fewer or no teeth avoid fibrous foods resulting in reduced food intake and leaving out various sources of proteins, fibers, minerals, and vitamins [10],[11].

Selecting less nutritious food leading to high risk of malnutrition and consequently the potential for cardiovascular disease and cancer [12],[13]. In fact, the masticatory force of completely edentulous patients is 20–40% of that of healthy dentate persons. Therefore, complete denture wearers need up to seven times more chewing strokes to reduce food particle than do dentulous participants [14],[15].

The chewing forces used by denture wearers may be limited by the discomfort and the pain that happens when one or both of the dentures lose their retention, or even by the fear of such pain. The MBF that can be exerted by denture wearers on objects placed between their dentures has also been shown to be considerably lower than that observed in dentate persons [5].

Three principal factors; retention, stability, and support should be considered for successful dentures. Treatment alternatives that aid in increasing retention and stability for improving denture function should be considered when conventional denture therapy is inadequate. One of these alternatives is using thermoplastic denture base material [4].

Thermoplastic dentures are introduced as alternative to traditional hard-fitted dentures [16]. Thermoplastic resins can be broadly classified as thermoplastic acetal, thermoplastic polycarbonates, thermoplastic acrylic, and thermoplastic nylon [17],[18]. The mechanical properties of thermoplastic denture base in comparison with the conventional heat-cured PMMA and fiber reinforced PMMA denture base materials were studied. The thermoplastic denture base material had the highest transverse strength and no fracture was observed [19].

Polyamide resin is produced from the polymerization of diamine and dibasic acid with properties suitable for high-quality elastic denture materials, such as low solubility, high thermal resistance and flexibility, high strength, and superior moldability. Despite these advantages, unlike common PMMA acrylic resins, polyamide resins have difficulties in reline and repair when relining becomes necessary because of resorption of the alveolar bone under the denture base [19].

To overcome this drawback, the thermoplastic PMMA resin, which is produced by using an injection molding method, has recently been introduced. It contains PMMA components that are found in auto-polymerized and heat-polymerized relining resins; this allows it to be applied for relining, thereby overcoming the drawback of existing elastic dentures made of polyamide resins [20].

Quality of health is defined as a subjective, phenomenological, multidimensional construct based on individual's internal frame of reference [21].

Rehabilitation of edentulism tends to improve oral health-related quality of life (OHRQoL) but some individuals may still have some impact on it due to misfits, adaptation phase or because individual lack of acceptance of their dentures [22]. Oral epidemiology has used measures, which assess the extent to which oral conditions disrupt normal social role functioning and lead to major changes in behavior, such measures are known as sociodental indicators or OHRQoL measures [23].

Measuring OHQoL is also essential for epidemiological and clinical studies for health improvement and diseases prevention [24]. Among the most commonly used instruments for assessment of OHQoL are the Geriatric Oral Health Assessment Index (GOHAI) and Oral Health Impact Profile (OHIP). Most of the OHQoL instruments that have been shown to have adequate validity and reliability are based on three main dimensions: physical symptoms, perception of well-being and functional capacity [25],[26].

The GOHAI has 12 questions in three subscales: (a) physical function; (b) psychosocial function, and (c) pain or discomfort [22]. The OHIP was developed in Australia by Gary D. Slade and A. John Spencer in 1994. It is divided into seven constitutive domains: functional limitations (nine questions), physical pain/discomfort (nine questions), psychological discomfort (five questions), physical disability (nine questions), psychological disability (six questions), social disability (five questions), and handicap (six questions) [26].

OHIP is a commonly used questionnaire for assessing OHRQoL [27]. It is an important instrument in defining social impacts of oral disorders and in evaluation of dental treatment [28]. It is also useful in the assessment of physical, mental, and social well-being, and is potentially useful for informing healthcare decision making [29].

The OHIP is a 49-item profile that describes the impacts of oral health conditions on aspects of function. Daily living and social interactions in seven domains. including functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap [26].

The OHIP constituted 49 lengthy questions and partly for this reason there was a need to develop a shorter derivative. In 1997, Slade published the OHIP-14 [26],[30].

The OHIP-14 proved to have good statistical properties and validity. The benefit of using the OHIP-14 is that data can be collected using less fieldwork and respondent burden. However, statements relevant to denture wearing were excluded in the OHIP-14 [31].

Allen and Locker [32] found that improvements following clinical intervention could not be measured and that the shortened version did not include on item related to perceived chewing difficulty – a common problem for patients wearing removable dentures. As a result, another shortened version of the OHIP was developed to be used in the prosthodontic setting, namely the oral health impact profile for edentulous patients (OHIP-EDENT) [33].

The OHIP-EDENT is an OHIP-49's adapted version retaining the most significant questions from each original subscale because this is considered too long for being used in epidemiological studies [34]. It is a questionnaire on OHRQoL comprising only 19 items instead of 49 questions in original OHIP [35]. OHIP-EDENT's subscales are functional limitation, physical pain, psychological discomfort, physical disability, psychological disability, social disability, and handicap. It is indicated to use for OHRQoL evaluation with elderly or after replacing missing teeth [22].

Mesko et al. [22] compared GOHAI and OHIP-EDENT in complete and partial denture wearers and they concluded that OHIP-EDENT was more sensible than GOHAI, except for Kennedy class I and II complete dentures. Sato et al. [35] tested the reliability and validity of a Japanese version of the OHIP for edentulous participants and they found that OHIP-EDENT demonstrated good reliability and validity. Allen and McMillan [36] reported an improved OHRQoL among patients who received conventional complete dentures. Similarly, in a sample of 34 patients, treatment with a conventional complete denture began to improve the OHRQoL within a month of insertion and continued to improve the OHRQoL 6 and 12 months after treatment [37].

The OHIP-EDENT includes seven subscales as shown in [Table 1]. Functional limitation (three items), physical pain (four items), psychological discomfort (two items), physical disability (three items), psychological disability (two items), social disability (three items), and handicap (two items). Participants responded by rating the frequency with which oral health-related problems had impacted their daily activities during the past month (0: never, 1: hardly ever, 2: occasionally, 3: fairly often, and 4: very often). The OHIP-EDENT is scored between 0 and 76, and the lower scores representing a better OHRQoL [35].{Table 1}

The present study compared MPF and OHIP in complete denture wearers with heat-polymerizing hard PMMA and thermoplastic PMMA, after 1 and 6 months of complete denture placement.

 Patients and Methods



A total of 26 completely edentulous patients whose average age was 42–56 years (mean: 48 years) were selected from outpatient clinic, Remvable Prosthodontic Department, Al-Azhar University. All the patients studied have no psychiatric disease or movement disorders.

Based on SD from pilot study and previous studies it was found that 26 cases are enough for conducting the research at power 0.80, confidence interval 0.95, and α level 0.05.

Ethical approval was obtained from Research and Ethics Committee, Faculty of Dental Medicine, Al-Azhar University. An informed consent form was obtained from each participant, after clarifying the objective of the study, its methodology, and the participants' rights.

Two types of complete dentures were made for each patient; heat-polymerizing hard PMMA (Dentaplast Opti-Press TM bredent GmbH & Co.KG, Senden, Germany) (group I) and a thermoplastic PMMA (Polyan IC TM bredent GmbH & Co.KG, Germany) (group II). Each patient weared the second denture after 8 months as there was 2 months as a rest period between two denture.

Heat-polymerizing hard PMMA complete denture construction

The patients recived a heat-polymerizing hard PMMA complete denture with even occlusion and free from discomfort (group I).

Bite force recordings

The bite force was recorded with a heat-polymerizing hard PMMA complete denture after 1 month and 6 months with the following method. The MBF was measured bilaterally at the first molars region by an occlusal force meter. The measuring range was 0–1000 N with an accuracy of ± 1 N (GM10; Nagano Keiki, Tokyo, Japan) [Figure 1].{Figure 1}

The instrument was placed at the first molar area. The patients were instructed to bite as powerfully as possible three times per side at maximum intercuspation, with a rest time of 2 min in between. The mean maximum occlusal force for the three readings was recorded in kilo Newtons (kN) and was considered to be the patient's MBF. Measurements were made with the patient in an upright position after 1 month and 6 months of prosthesis placemen [Figure 2].{Figure 2}

Measurement of oral health-related quality of life using oral health impact profile for edentulous patients

The OHIP-EDENT [Table 1] was translated into Arabic by two accredited translators, and then back translated into English by two different accredited translators. Both the English and the Arabic versions were applied alternately to 10 bilingual volunteers. Each volunteer was interviewed by one trained and experienced interviewer, and the interviewer recoded any difficulty that volunteers had encountered. To develop the final version of Arabic OHIP-EDENT, a discussion session with the interviewer was arranged, to clarify the volunteers' comments to make the questionnaire more understandable.

Oral examination was carried out by a single examiner and denture wearing status was recorded after completion of questionnaire. After 6 months of conventional heat-cured PMMA complete denture insertion, patients were asked to complete a modified short version of the OHIP (OHIP-EDENT) for assessing health-related quality of life in edentulous patients.

Thermoplastic PMMA complete denture construction

The patients recived a thermoplastic PMMA complete denture [Figure 3], with even occlusion and free from discomfort (group II). The bite force was recorded again after 1 month and 6 months of denture placement as described previously. After 6 months of thermoplastic PMMA complete denture insertion, patients were asked to complete a modified short version of the OHIP (OHIP-EDENT) for assessing health-related quality of life in edentulous patients. Statistical analysis was completed using SPSS software V. 21 (SPSS Inc., Chicago, Illinois, USA).{Figure 3}

 Results



Bite force measurements

The MBF with different denture base material in completely edentulous patients was recorded. The mean measurements of MBF for patients with heat-polymerizing hard PMMA were 0.1036 and 0.1463 kN at 1 month and 6 months after denture placement, respectively. The mean measurements of MBF for patients with thermoplastic PMMA were 0.1063 and 0.1491 kN at 1 month and 6 months after denture placement, respectively [Table 2] and [Figure 4].{Table 2}{Figure 4}

The paired t-test revealed that there was no statistical difference in MBF values between both types of denture base after 1 month of denture insertion (P = 0.399, >0.05). The bite force increasing considerably after 6 months of denture use in both types of denture base. After 6 months of denture placement, when comparing both groups, there were statistically significant differences in bite force values between both types of denture base (P = 0.007, <0.05) [Table 2] and [Table 3]. Patient recorded higher MPF with a thermoplastic PMMA complete denture values more than heat-polymerizing hard PMMA complete denture.{Table 3}

Oral health-related quality of life measurements

After 6 months of denture use, OHRQoL was compared between heat-polymerizing hard PMMA complete denture and thermoplastic PMMA complete denture using OHIP-EDENT [Table 4] and [Table 5] compared the mean OHIP-EDENT scores for subscales and total scores between both groups. The results of the present study revealed that there was a statistical significant different between both groups in psychological discomfort and handicap subscale (P ≤ 0.05). On other hand there was no statistical significant different between both groups in relation to functional limitation, physical pain, physical disability, psychological disability, and social disability subscales (P > 0.05). The mean total OHIP-EDENT score for group I and group II were 33.10 and 36.57, respectively. There was a a statistical significant different between both groups in relation to The mean total OHIP-EDENT score (P ≤ 0.05).{Table 4}{Table 5}

 Discussion



MBF is an important variable for masticatory function evaluation [38],[39]. Bite force varies in different locations in the oral cavity and is highest in the first molar area because nearly 80% of the total bite force is distributed in that area [40],[41]. So it is more reliable to measure multiple recordings than a single recording [42].

Patients over 60 years were excluded, as they are more vulnerable to the trauma of oral mucosa, stomatitis due to atrophy with a slow turnover of tissues, an overall increase in the number of elastic fibers. Moreover, an old age people show a decrease in the muscles activity. Consequently, older people tend to have weak neuromuscular control [43].

The question raised in this study, is what denture base material (heat-polymerizing hard PMMA or a thermoplastic PMMA) provides better bite force and OHRQoL in completely edentulous patients.

After 1 month of denture insertion, there was no significance difference between patients with heat-polymerizing hard PMMA complete denture and patients with a thermoplastic PMMA complete denture.

After 1 month of denture insertion, bite force measurements were 0.1036 and 0.1063 kN for the group I and group II, respectively. Bite force is increasing considerably after 6 months of denture use in both groups. It measures 0.1463 and 0.1491 kN for the group I and group II, respectively. These results match the findings of Roldan et al. [44], It is important to mention that although there were only 6 months between measurements, improvement in bite force were observed and may be explained by the adaptation period to the new prosthesis [45],[46]. This result is in agreement with the finding of Borie et al. [9] who found that MBF was found to increase significantly after 1 month of use.

The MBF values were considerably higher in patients with a thermoplastic PMMA complete denture than patients received heat-polymerizing hard PMMA complete denture after 6 months of denture use. It measures 0.1491 kN for patients received thermoplastic PMMA complete denture while in patients received heat-polymerizing hard PMMA complete denture it measures 0.1063 kN. The higher values observed in patients received thermoplastic PMMA denture may be directly related to better stability and adaptation obtained with a thermoplastic PMMA denture base.

An assessment of OHRQoL in completely edentulous patients was done using OHIP-EDENT. The OHIP-EDENT was selected to measure the OHRQoL in edentulous patients as it showed satisfactory reliability, validity, and agreement with reported complaints in many languages [35],[47],[48],[49]. It appears to be a reliable and valid instrument to measure OHRQoL. This makes the instrument a good tool for comparison of this important variable between different countries and cultures [47],[48].

The results of the current study showed that, the mean OHIP-EDENT subscales scores for functional limitation were 6.63 and 6.80 for group I and group II, respectively. The mean OHIP-EDENT subscales scores for physical pain were 5.81 for group I and 6.18 for group II. There was no statistical significant different between both groups in relation to functional limitation, physical pain, and physical disability, this can be explained by an adequate adaptation of the prostheses for both groups. Thus, it can be stated that oral rehabilitation with conventional and flexible denture provided satisfactory function, at least from the subjective perception.

Adam et al. [33], evaluated the impact of new complete dentures on OHRQoL and they found that there was a significant improvements in more than half of the domains of the OHIP-EDENT 2–3 months postinsertion. Therefore, they concluded that new complete dentures can improve the OHRQoL of patients.

Viola et al. [50] measured OHRQoL and satisfaction before and after treatment with complete dentures. They found that all domains of OHIP-EDENT showed significant improvements.

Regarding psychological discomfort and handicap subscale, the results of the present study revealed that there was a statistical significant different between both groups. This is an important finding as a certain level of discomfort or handicap may be acceptable to one patient and intolerable to another.

Hadzipasic-Nazdrajic [27] evaluate the OHRQoL and concluded that patients with new dentures had significantly better QoL compared with the QoL in participants with worn dentures.

The mean total OHIP-EDENT scores were 33.10 for group I and 36.57 for group II. These results may be explained as the main complaints of edentulous patients for replacement of their old dentures were denture instability and soreness, probably due to alveolar bone resorption and reduced tissue fit, so the treatment with thermoplastic complete dentures resulted in a positive impact on quality of life.

The findings from this study support the idea that patients wearing thermoplastic complete dentures are more likely to feel positive impacts on their quality of life after treatment with new dentures.

 Conclusion



Completely edentulous patients received a thermoplastic PMMA denture was found to significantly have better MBF values after 6 months of denture use as compared to patients received heat-polymerizing hard PMMA complete dentures. OHIP for thermoplastic PMMA record better values more than a heat-polymerizing hard PMMA complete dentures after 6 months of denture use.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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