An Objective and Subjective Evaluation of Masticatory Efficiency in Periodontal Patients Before and After Basic Periodontal Therapy: A Case Series Study

Abstract

Background: Periodontal disease is a multifactorial infectious pathology that affects dental supporting tissues, impacting the health and quality of life of patients. Assessing chewing efficiency before and after periodontal therapy is crucial to better understand its impact on the quality of life of periodontal patients. Thus, the aim of this case series study was to determine whether basic periodontal therapy improves masticatory ability and efficiency in patients with mild to moderate periodontitis. Methods: A prospective, longitudinal, case series study was carried out in 42 periodontal patients treated at the University Odontology Clinic. Masticatory efficiency before and after basic periodontal treatment was assessed using both objective (HueCheck Gum test) and subjective (Quality of Masticatory Function Questionnaire: QMFQ) methods. Results: Significant improvements (p = 0.0001) were observed in periodontal variables such as hygiene index (HI), probing depth (PD), and clinical attachment level (CAL), as well as in the initial and final QMFQ total score (p = 0.045). In addition, significant differences were found in post-treatment QMFQ scores related to parafunctional habits (p = 0.046) and facial patterns, especially in meat consumption (p = 0.042) fruit and vegetable consumption (p = 0.007, p = 0.044). The initial mean HueCheck Gum test values were 0.59 ± 0.09 and the final values were 0.61 ± 0.11. These differences were not statistically significant. Conclusions: Basic periodontal treatment does not objectively improve the masticatory efficiency of patients with mild–moderate periodontitis, evaluated by means of the test of mixing two chewing gums, but it does offer subjective improvements.

1. Introduction

Periodontitis is an irreversible chronic inflammation characterized by the destruction of dental support tissues (periodontal ligament and alveolar bone), the presence of periodontal pockets, and gingival bleeding [1]. It can affect up to 50% of the adult population, of which 10–15% suffer the most severe variants [2]. The disease can go through several stages of insertion loss [1] which will affect the aesthetics and masticatory function of the patient and, ultimately, their quality of life.

The periodontal ligament is made up of collagen fibres that connect the root of the tooth to the alveolar bone and have mechanoreceptors, which are responsible for sending signals to the brain about the forces exerted by the teeth when holding, biting, or chewing food [3]. The loss of periodontal support as a consequence of periodontitis will alter the sensory function of the mechanoreceptors, generating specific dysfunctions in mastication, which can affect the final product of mastication [4]. In addition, there are studies that indicate that both masticatory muscles [5] as well as the bite force of the molars [6] in periodontal patients have less activity than in patients without periodontitis. All of this may result in patients avoiding tough, fibrous, and hard-to-chew foods, potentially leading to malnutrition and systemic issues [7,8].

Evaluating the impact of periodontal disease on masticatory function and the patient’s quality of life is crucial when diagnosing and treating periodontal patients. For this purpose, there are two types of methods: objective and subjective methods [9]. Objective methods assess the mixing capacity of the food bolus and provide quantitative numerical data, using techniques such as fractional sieving, spectrophotometry, glucose mediators, or digital image analysis of the chewed food during a certain number of masticatory cycles [9]. In contrast, subjective methods allow patients to express their perception of their chewing ability and quality of life, using self-assessment questionnaires, visual analogue scales, or indices based on the perceived difficulty in chewing different types of food [10]. Although some studies have found a significant correlation between both methods [11,12,13], others determine a weak or non-existent correlation [14,15].

On the other hand, basic periodontal therapy has proven to be effective in treating periodontitis at mild to moderate stages, particularly from a clinical perspective [16], as well as the patient’s quality of life [17]. However, there are very few studies that objectively assess the masticatory function of patients with mild to moderate periodontitis and whether it improves after basic periodontal treatment.

The main objective of this case series study is to determine whether basic periodontal treatment improves masticatory capacity and efficiency in patients with mild–moderate periodontitis, from an objective and/or subjective point of view, and whether there is any type of correlation between both methods. As a secondary objective, we intend to analyse whether variables such as gender, facial patterns, or parafunctional habits influence the results obtained in terms of masticatory efficiency.

2. Material and Methods

2.1. Clinical Sample

The sample for this case series study consisted of 42 patients (14 men and 28 women), all diagnosed with stage II or III periodontitis, grade B [18]. The selection method followed a non-probabilistic sequential model. The sample comprised patients seeking treatment at the University Dental Clinic of Morales Meseguer Hospital in Murcia, Spain. The study lasted 8 months, from September 2023 to May 2024.

2.2. Ethical Considerations

This study followed the Code of Ethics of the World Medical Association (Declaration of Helsinki, 1964) for experiments involving humans and was approved by the Research Ethics Committee of the University of Murcia (M10/2023/117, ACTA3/CEI). Once patients met the inclusion criteria, they were informed about the study and signed an informed consent form.

The inclusion criteria were as follows:

(a)

Patients over 18 years old.

(b)

Diagnosed with periodontitis stage II or III, grade B [18].

(c)

Signed informed consent.

(d)

At least 20 teeth with antagonists.

(e)

Completion of basic periodontal treatment, attending a follow-up visit one month after the last scaling and root planing.

(f)

Patients had to understand and properly complete the Quality of Masticatory Function Questionnaire (QMFQ).

The exclusion criteria were as follows:

(a)

Pregnancy or lactation.

(b)

Systemic diseases affecting immune response.

(c)

Periodontal treatment in the last 12 months.

(d)

History of neoplasm or maxillofacial radiotherapy in the past 5 years.

(e)

Patients without periodontitis or with periodontitis stage I or IV, or grade A or C.

(f)

Smoking.

(g)

Use of removable prostheses.

2.3. Clinical Method

Once patients were diagnosed with stage II or III periodontitis, grade B, they were informed about the necessary treatment and the study procedures. If they agreed to undergo treatment (steps 1 and 2 of the EFP S3 guideline) [19] and participate in the study, they received information sheets and signed the informed consent form. Next, they completed the QMFQ (pre-treatment) and performed the HueCheck Gum test.

Steps 1 and 2 of the EFP S3 guideline included oral hygiene instructions, recommendations for healthy habits (e.g., smoking cessation), and supragingival cleaning using an ultrasonic device. Subgingival instrumentation was performed only when probing depth was ≥4 mm. The instruments used were a reduced set of Gracey Mini Five™ Curettes (Hu-Friedy, Chicago, IL, USA). A different quadrant was treated each week, completing the entire treatment in 4 weeks. The second QMFQ and HueCheck Gum test (post-treatment) were performed during periodontal re-evaluation one month after the last treated quadrant (Figure 1).

The QMFQ [20] consists of 26 questions on the frequency of disfunction for two prior weeks and is grouped into 5 domains: foods–mastication, habits, steak, fruits, and vegetables. The answers are recorded on a Likert scale, with values ranging from 0 to 4 coded as follows: 0 ‘never’ or ‘N/A’ (not apply) if the patient had not eaten these foods, 1 ‘hardly ever’, 2 ‘occasionally’, 3 ‘fairly often’, or 4 ‘very often’ (

Table 1. Quality of Masticatory Function Questionnaire (QMFQ).

FEEDING–CHEWING	Never	Hardy Ever	Occasionally	Fairly Often	Very Often	N/A
Do you have difficulty chewing beef cut into small pieces?
2. Do you have difficulty chewing chicken meat cut into small pieces?
3. Do you have difficulty chewing ground meat?
4. Do you have difficulty biting into hard, raw, whole vegetables?
5. Do you have difficulty biting into hard, raw, whole fruits?
6. Do you have difficulty biting into hard, raw, quartered fruit?
7. Do you have difficulty eating the peel of hard raw fruits?
8. Do you have difficulty chewing bread with a hard crust?
9. Do you have difficulty chewing nuts and seeds?
HABITS
10. Did you have to drink while eating to make swallowing easier?
11. Have you added sauce to your food to make it easier to swallow?
12. Have you dipped food in liquids to make it easier to chew and swallow?
13. In general, is the food you swallow well chewed?
MEATS
14. Have you ever had to cut beef into small pieces?
15. Have you ever had to shred beef before eating it?
16. Have you had to cut the chicken into small pieces?
17. Have you ever had to shred chicken before eating it?
18. Have you ever had to cook meat until it fell apart before eating it?
FRUIT
19. Have you ever eaten whole, raw apples?
20. Have you ever had to peel apples before eating them?
21. Have you had to cut them into four to chew them?
22. Have you had to cut apples into small pieces to chew them?
23. Have you ever had to crush or grate hard raw fruits to eat them?
VEGETABLES
24. Have you ever eaten whole, raw carrots?
25. Have you had to cut raw carrots into small pieces to chew them?
26. Have you had to puree hard vegetables to eat them?

). The responses of the QMFQ are added to give the total QMFQ score and can range from 0 to 104, with a high score indicating a worse mastication quality.

For the HueCheck Gum test [21], two pieces of gum, blue and pink, measuring 8 mm × 20 mm × 12 mm, were used. These chewing gums were developed and produced by Orophys GmbH (Muri b. Bern, Switzerland). They are sugar-free, uncoated, mint-flavoured gums. Their texture is similar to that of commercial chewing gum. The gum was prepared according to the original protocol [22]. Both gums were chewed at once by the patients for 20 chewing cycles. After that, the sample was collected and evaluated by means of optoelectronic analysis performed with Viewgum^® software 1.0 (Figure 2) https://www.dhal.com/viewgum.htm (accessed on 4 May 2024) (dHAL Software 4.1.4.1, Kifissia, Greece).

Images from the HueCheck Gum test were imported into Viewgum^® software, which analysed the colours of the gum and calculated the variation in hue (VOH). The software transformed the images into the HSI colour space and calculated the hue value for each pixel. The VOH is the measure that we used to evaluate the masticatory efficiency, and it varied in the interval [0, 1]. Values near to 1 meant 100% heterogeneity, corresponding to poor mastication, and values closer to 0 implied 100% homogeneity, indicating adequate mastication (Figure 2).

After periodontal re-evaluation, patients who continued with pockets of 4 or 5 mm, with bleeding on probing, were re-treated with subgingival instrumentation, while those with pockets ≥6 mm with bleeding on probing underwent periodontal surgery.

2.4. Statistical Analysis

The sample size calculation was performed using the Excel calculator available on the Fisterra website (https://www.fisterra.com/formacion/metodologia-investigacion/determinacion-tamano-muestral/#sec4 (accessed on 3 September 2023).

The parameters were as follows:

• “N” (Initial Sample Size): Based on the sample size from the Halazonetis study [23].
• Measured Variable: The hue value obtained from the HueCheck Gum test.
• Precision (d): A margin of 0.15 points for accuracy.
• Significance Level (α): 0.05 (95% confidence level).
• Power (1 − β): 90% (10% probability of type II error).

Based on these parameters, the minimum required sample size was 19 patients. To account for dropouts or missing data, a 15% increase was applied, resulting in a final sample size of 22 individuals. This approach ensured adequate statistical power for robust and reliable conclusions.

Data were analysed using SPSS version 23.0 (SPSS, Chicago, IL, USA). Normality was assessed with the Shapiro–Wilk test. Descriptive and inferential statistics were analysed using Tukey’s exploratory data analysis and Student’s t-test for the five questionnaire domains, foods–mastication, habits, steak, fruits, and vegetables, as well as for total QMFQ scores (pre- and post-treatment) and the hue value from ViewGum^® software.

In order to assess the influence of gender, facial pattern, and parafunctional habits on QMFQ and HueCheck Gum test scores, a one-way ANOVA was performed. Additionally, the Pearson correlation test was used to quantify the linear relationship between QMFQ and HueCheck Gum test scores. The significance level was set at p < 0.05.

3. Results

Of the 42 patients initially enrolled in the study, 10 did not complete it due to non-compliance with follow-up appointments. The patient sample that completed the study consisted of 32 patients, with a mean age of 53 ± 10 (34–71). Fourteen were men and eighteen were women. Regarding facial patterns, 15 were mesofacials, 4 were dolichofacials, and 13 were brachyfacials. Six of these patients performed parafunction, and twenty-six did not.

3.1. Comparison of the Sample Before and After Periodontal Treatment

Statistically significant differences were found between the periodontal variables hygiene index (HI), probing depth (PD), and clinical attachment level (CAL) before and after periodontal treatment, as well as between the total score of the initial and final QMFQ. However, these differences were not found between the score obtained in the HueCheck Gum test before and after periodontal treatment (

Table 2. Comparison between periodontal variables and questionnaire as well as HueCheck Gum test before and after periodontal treatment.

Variable	Initial (Mean ± SD)	Final (Mean ± SD)	Significance (p-Value)
HI	30.15 ± 32.71	13.10 ± 17.27	0.0001
PD	2.46 ± 0.67	1.88 ± 0.53	0.0001
CAL	3.26 ± 1.19	2.50 ± 0.74	0.0001
Total score QMFQ	25.06 ± 18.43	22.62 ± 14.26	0.045
HueCheck Gum Test	0.59 ± 0.09	0.61 ± 0.11	0.667

HI: hygiene index; PD: probing depth; CAL: clinical attachment level; QMFQ: Quality of Masticatory Function Questionnaire.

).

3.2. The Behaviour of the Variables “Gender”, “Facial Pattern”, and “Parafunction” in the Scores of the QMFQ and the HueCheck Gum Test

(a)

Gender:

No significant differences were found in the QMFQ or HueCheck Gum test scores pre- or post-treatment according to the “gender” variable (

Table 3. The degree of significance of the differences between the groups separated by “gender”.

Variable	Men (Mean ± SD)	Women (Mean ± SD)	Significance (p-Value)
Total score QMFQ pre-treatment	27 ± 20.7	23.55 ± 16.92	0.46
Total score QMFQ post-treatment	24.92 ± 16.39	20.83 ± 12.54	0.42
HueCheck Gum test pre-treatment	0.63 ± 0.42	0.55 ± 0.16	0.64
HueCheck Gum test post-treatment	0.59 ± 0.16	0.61 ± 0.02	0.72

).

(b)

Facial pattern:

In the pre-treatment QMFQ, statistically significant differences were found in the food group “fruit” between dolichofacial and brachyfacial patients (

Table 4. The degree of significance of the differences between the groups separated by “facial pattern” with respect to the total pre-treatment sample.

Dependent Variable	(I) Facial Pattern	(J) Facial Pattern	Mean Difference (I-J)	Standard Error	Sig.	95% Confidence Interval
						Lower Bound	Upper Bound
FRUIT	Dolichofacial	Mesofacial	4	1.91	0.129	−0.781	8.781
		Brachyfacial	4.92	1.94	0.047	0.053	9.782

).

In the post-treatment QMFQ, statistically significant differences were found in the items “meat consumption” and “fruit” between dolichofacial, mesofacial, and brachyfacial patients (

Table 5. The degree of significance of the differences between the groups separated by “facial pattern” with respect to the total post-treatment sample.

Dependent Variable	(I) Facial Pattern	(J) Facial Pattern	Mean Difference (I-J)	Standard Error	Sig.	95% Confidence Interval
						Lower Bound	Upper Bound
MEATS	Dolichofacial	Mesofacial	6.66	2.63	0.051	−0.015	13.349
		Brachyfacial	7.00	2.67	0.042	0.211	13.789
FRUITS	Dolichofacial	Mesofacial	6.48	1.94	0.007	1.539	11.428
		Brachyfacial	5.13	1.98	0.044	0.111	10.158

).

(c)

Parafunction:

Significant differences were found in the post-treatment QMFQ scores in the “vegetable consumption” section in relation to the “parafunction” variable (

Table 6. The degree of significance of the differences between the groups separated by “parafunction” with respect to the total sample in relation to the scores of the post-treatment QMFQ.

ANOVA
		Sum of Squares	df	Mean Square	F	Sig.
Vegetables	Between Groups	12.72	1	12.72	4.32	0.046

).

3.3. The Correlation Between the QMFQ and the HueCheck Gum Test

No statistically significant correlation was found between the QMFQ scores and the HueCheck Gum test.

4. Discussion

The main findings of this study indicate that patients with mild to moderate periodontitis subjectively perceived an improvement in their masticatory efficiency after basic periodontal treatment; however, objective measures did not reflect this improvement. Objectively, patients exhibited similar chewing performance before and after periodontal therapy, with the values obtained using the HueCheck Gum test indicating a masticatory efficiency closer to poor rather than adequate.

4.1. Assessment Methods of Masticatory Function

Various methods exist to evaluate masticatory function in periodontal patients. This study employed Hue-Check Gum^® as an objective method and the QMFQ as a subjective assessment tool. Chewing gum offers advantages such as consistent texture over time and ease of sample retrieval for analysis. Similar methodologies have been utilized by Kosaka et al. [24] and Van Der Bilt et al. [25]. However, one drawback is that the chewing experience with gum differs from that with natural foods [9] and may also require specialized software, such as Viewgum^®, for analysis [23].

The chewing gum mixing test used in this study was originally developed and refined by Schimmel et al. [22] and Halazonetis [23], later validated by Buser et al. [21] and Schimmel [26]. This gum maintains its consistency and durability over time [27], ensuring constant testing conditions and increased reliability. It has been widely recognized for its ease of measurement and analysis [26,27,28].

Conversely, other studies by Kapur et al. [29], Mowlana et al. [30], and Abe R et al. [31] have assessed masticatory function using natural foods such as nuts, raw carrots, or rice with the sieving method. While this approach allows for a more realistic evaluation, the physical variability of natural foods makes standardization challenging [9].

4.2. Subjective Assessment with the QMFQ

The QMFQ was originally developed in French for denture-wearing patients in Montreal, Quebec, under the name “Questionnaire D’Alimentation” [32,33]. Initially comprising 38 questions, it was later reduced to 26 by Hilasaca-Mamani [20]. Barbe et al. [27] and Muller et al. [33] confirmed its reliability in evaluating masticatory function. Alternative questionnaires, such as the OHIP-14 and OIDP, have been used to assess the impact of oral health on daily life [17,34] but are less specific to masticatory function. The Visual Analogue Scale (VAS) has also been utilized [35,36], yet it lacks specificity regarding food types.

4.3. Clinical Findings and Periodontal Outcomes

Basic periodontal treatment significantly improved periodontal parameters (p = 0.0001), except for BoP:

• HI decreased from 30.14% ± 32.71% to 13.10% ± 17.28%.
• Mean PD decreased from 2.46 ± 0.67 mm to 1.88 ± 0.53 mm.
• CAL improved from 3.26 ± 1.19 mm to 2.51 ± 0.74 mm.

These results align with clinical practice guidelines for stage I-III periodontitis treatment [16]. The lack of BoP improvement may be due to patients brushing more thoroughly only on the day of re-evaluation, masking true gingival inflammation [37]. Additionally, a one-month re-evaluation period may be insufficient for complete periodontal tissue repair, which can take up to eight weeks [38].

Masticatory function showed significant subjective improvements (p = 0.045), with total QMFQ scores decreasing from 25.06 ± 18.44 to 22.63 ± 14.26. These results align with findings by Pereira et al. [39], who attributed subjective improvements to reduced inflammation, pain relief, and potential mechanoreceptor regeneration. However, HueCheck Gum test values remained unchanged before (0.59 ± 0.09) and after treatment (0.61 ± 0.11), indicating no objective improvement in masticatory efficiency. Similar to our findings, Müller et al. [33] noted that subjective chewing perception can be influenced by psychological adaptability. In contrast, Barbe et al. [27] found a significant correlation between objective masticatory efficiency and QMFQ scores (p = 0.037), particularly in stage IV periodontitis patients.

A possible “placebo effect” may have contributed to the perceived improvement, as patients undergoing treatment might expect positive changes in their condition. Although no prior studies have objectively evaluated masticatory efficacy post-periodontal treatment, Barbe et al. [27] and Kosaka et al. [24] established associations between periodontal status and masticatory performance.

4.4. Influence of Gender, Facial Pattern, and Parafunctional Habits

Statistically significant differences were observed in facial pattern and parafunctional habits from a subjective perspective. In the initial QMFQ, dolichofacial patients had significantly higher scores (p = 0.047) than brachyfacial patients when consuming fruits. Post-treatment, dolichofacial patients still reported worse chewing for fruits (p = 0.007) and meats (p = 0.042) compared to other facial patterns. These findings confirm previous studies indicating that dolichofacial patients tend to have weaker masticatory muscles [40,41].

Regarding parafunctional habits, patients with such habits reported significantly worse chewing of vegetables (p = 0.046) after treatment compared to those without parafunctions. This could be attributed to bruxism or clenching, which may cause occlusal wear, abfractions, and joint or muscle dysfunction [42]. However, Sterenborg et al. [43] suggested that while individual cases may show a link between dental wear and mastication, no significant relationship was observed at the group level. Other factors, such as bite force and functional occlusal units, could play a role.

4.5. Limitations and Clinical Relevance

This study’s main limitations include a small initial sample size (N = 42), which was further reduced due to ten patients missing their re-evaluation appointments. Additionally, the one-month follow-up period may have been insufficient to detect substantial changes in masticatory function. Some patients did not perceive masticatory issues before treatment or only became aware of them through the questionnaire. Furthermore, as the QMFQ is not validated in Spanish, language differences may have impacted response accuracy.

Clinically, this study underscores that basic periodontal treatment not only improves periodontal parameters but also enhances patients’ subjective perception of chewing ability. This may encourage adherence to oral hygiene and maintenance appointments. Moreover, this study suggests that the QMFQ could be particularly useful for assessing masticatory difficulties in dolichofacial or parafunctional patients, as these individuals struggle with chewing certain foods, which could lead to nutritional deficiencies. However, the HueCheck Gum test results indicate that masticatory function in mild to moderate periodontitis patients remains closer to poor than adequate, despite their subjective improvement.

4.6. Future Research and Conclusions

Future studies should include larger sample sizes, compare healthy patients with different stages of periodontitis, and determine HueCheck Gum test values for each group. Additionally, further research should investigate whether comprehensive treatments, including prosthetics or dental implants, significantly improve masticatory function.

In conclusion, patients with mild to moderate periodontitis exhibited masticatory function closer to poor than adequate, both before and after basic periodontal treatment. While this treatment did not objectively improve masticatory efficiency, it did enhance subjective perception. Facial patterns and parafunctional habits influenced patients’ subjective masticatory function, and no correlation was found between the objective and subjective assessment methods used in this study.